1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>.
7 * Copyright 2012 John Marino <draco@marino.st>.
8 * Copyright 2014-2017 The FreeBSD Foundation
9 * All rights reserved.
10 *
11 * Portions of this software were developed by Konstantin Belousov
12 * under sponsorship from the FreeBSD Foundation.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 */
34
35 /*
36 * Dynamic linker for ELF.
37 *
38 * John Polstra <jdp@polstra.com>.
39 */
40
41 #include <sys/param.h>
42 #include <sys/mount.h>
43 #include <sys/mman.h>
44 #include <sys/stat.h>
45 #include <sys/sysctl.h>
46 #include <sys/uio.h>
47 #include <sys/utsname.h>
48 #include <sys/ktrace.h>
49
50 #include <dlfcn.h>
51 #include <err.h>
52 #include <errno.h>
53 #include <fcntl.h>
54 #include <stdarg.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <unistd.h>
59
60 #include "debug.h"
61 #include "rtld.h"
62 #include "libmap.h"
63 #include "rtld_paths.h"
64 #include "rtld_tls.h"
65 #include "rtld_printf.h"
66 #include "rtld_malloc.h"
67 #include "rtld_utrace.h"
68 #include "notes.h"
69 #include "rtld_libc.h"
70
71 /* Types. */
72 typedef void (*func_ptr_type)(void);
73 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
74
75
76 /* Variables that cannot be static: */
77 extern struct r_debug r_debug; /* For GDB */
78 extern int _thread_autoinit_dummy_decl;
79 extern void (*__cleanup)(void);
80
81 struct dlerror_save {
82 int seen;
83 char *msg;
84 };
85
86 /*
87 * Function declarations.
88 */
89 static const char *basename(const char *);
90 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
91 const Elf_Dyn **, const Elf_Dyn **);
92 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
93 const Elf_Dyn *);
94 static bool digest_dynamic(Obj_Entry *, int);
95 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
96 static void distribute_static_tls(Objlist *, RtldLockState *);
97 static Obj_Entry *dlcheck(void *);
98 static int dlclose_locked(void *, RtldLockState *);
99 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
100 int lo_flags, int mode, RtldLockState *lockstate);
101 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
102 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
103 static bool donelist_check(DoneList *, const Obj_Entry *);
104 static void dump_auxv(Elf_Auxinfo **aux_info);
105 static void errmsg_restore(struct dlerror_save *);
106 static struct dlerror_save *errmsg_save(void);
107 static void *fill_search_info(const char *, size_t, void *);
108 static char *find_library(const char *, const Obj_Entry *, int *);
109 static const char *gethints(bool);
110 static void hold_object(Obj_Entry *);
111 static void unhold_object(Obj_Entry *);
112 static void init_dag(Obj_Entry *);
113 static void init_marker(Obj_Entry *);
114 static void init_pagesizes(Elf_Auxinfo **aux_info);
115 static void init_rtld(caddr_t, Elf_Auxinfo **);
116 static void initlist_add_neededs(Needed_Entry *, Objlist *);
117 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *);
118 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *);
119 static void linkmap_add(Obj_Entry *);
120 static void linkmap_delete(Obj_Entry *);
121 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
122 static void unload_filtees(Obj_Entry *, RtldLockState *);
123 static int load_needed_objects(Obj_Entry *, int);
124 static int load_preload_objects(const char *, bool);
125 static int load_kpreload(const void *addr);
126 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
127 static void map_stacks_exec(RtldLockState *);
128 static int obj_disable_relro(Obj_Entry *);
129 static int obj_enforce_relro(Obj_Entry *);
130 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
131 static void objlist_call_init(Objlist *, RtldLockState *);
132 static void objlist_clear(Objlist *);
133 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
134 static void objlist_init(Objlist *);
135 static void objlist_push_head(Objlist *, Obj_Entry *);
136 static void objlist_push_tail(Objlist *, Obj_Entry *);
137 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
138 static void objlist_remove(Objlist *, Obj_Entry *);
139 static int open_binary_fd(const char *argv0, bool search_in_path,
140 const char **binpath_res);
141 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp,
142 const char **argv0, bool *dir_ignore);
143 static int parse_integer(const char *);
144 static void *path_enumerate(const char *, path_enum_proc, const char *, void *);
145 static void print_usage(const char *argv0);
146 static void release_object(Obj_Entry *);
147 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
148 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
149 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
150 int flags, RtldLockState *lockstate);
151 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
152 RtldLockState *);
153 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *);
154 static int rtld_dirname(const char *, char *);
155 static int rtld_dirname_abs(const char *, char *);
156 static void *rtld_dlopen(const char *name, int fd, int mode);
157 static void rtld_exit(void);
158 static void rtld_nop_exit(void);
159 static char *search_library_path(const char *, const char *, const char *,
160 int *);
161 static char *search_library_pathfds(const char *, const char *, int *);
162 static const void **get_program_var_addr(const char *, RtldLockState *);
163 static void set_program_var(const char *, const void *);
164 static int symlook_default(SymLook *, const Obj_Entry *refobj);
165 static int symlook_global(SymLook *, DoneList *);
166 static void symlook_init_from_req(SymLook *, const SymLook *);
167 static int symlook_list(SymLook *, const Objlist *, DoneList *);
168 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
169 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
170 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
171 static void *tls_get_addr_slow(Elf_Addr **, int, size_t, bool) __noinline;
172 static void trace_loaded_objects(Obj_Entry *, bool);
173 static void unlink_object(Obj_Entry *);
174 static void unload_object(Obj_Entry *, RtldLockState *lockstate);
175 static void unref_dag(Obj_Entry *);
176 static void ref_dag(Obj_Entry *);
177 static char *origin_subst_one(Obj_Entry *, char *, const char *,
178 const char *, bool);
179 static char *origin_subst(Obj_Entry *, const char *);
180 static bool obj_resolve_origin(Obj_Entry *obj);
181 static void preinit_main(void);
182 static int rtld_verify_versions(const Objlist *);
183 static int rtld_verify_object_versions(Obj_Entry *);
184 static void object_add_name(Obj_Entry *, const char *);
185 static int object_match_name(const Obj_Entry *, const char *);
186 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
187 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
188 struct dl_phdr_info *phdr_info);
189 static uint32_t gnu_hash(const char *);
190 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
191 const unsigned long);
192
193 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
194 void _r_debug_postinit(struct link_map *) __noinline __exported;
195
196 int __sys_openat(int, const char *, int, ...);
197
198 /*
199 * Data declarations.
200 */
201 struct r_debug r_debug __exported; /* for GDB; */
202 static bool libmap_disable; /* Disable libmap */
203 static bool ld_loadfltr; /* Immediate filters processing */
204 static const char *libmap_override;/* Maps to use in addition to libmap.conf */
205 static bool trust; /* False for setuid and setgid programs */
206 static bool dangerous_ld_env; /* True if environment variables have been
207 used to affect the libraries loaded */
208 bool ld_bind_not; /* Disable PLT update */
209 static const char *ld_bind_now; /* Environment variable for immediate binding */
210 static const char *ld_debug; /* Environment variable for debugging */
211 static bool ld_dynamic_weak = true; /* True if non-weak definition overrides
212 weak definition */
213 static const char *ld_library_path;/* Environment variable for search path */
214 static const char *ld_library_dirs;/* Environment variable for library descriptors */
215 static const char *ld_preload; /* Environment variable for libraries to
216 load first */
217 static const char *ld_preload_fds;/* Environment variable for libraries represented by
218 descriptors */
219 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */
220 static const char *ld_tracing; /* Called from ldd to print libs */
221 static const char *ld_utrace; /* Use utrace() to log events. */
222 static struct obj_entry_q obj_list; /* Queue of all loaded objects */
223 static Obj_Entry *obj_main; /* The main program shared object */
224 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
225 static unsigned int obj_count; /* Number of objects in obj_list */
226 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
227 size_t ld_static_tls_extra = /* Static TLS extra space (bytes) */
228 RTLD_STATIC_TLS_EXTRA;
229
230 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
231 STAILQ_HEAD_INITIALIZER(list_global);
232 static Objlist list_main = /* Objects loaded at program startup */
233 STAILQ_HEAD_INITIALIZER(list_main);
234 static Objlist list_fini = /* Objects needing fini() calls */
235 STAILQ_HEAD_INITIALIZER(list_fini);
236
237 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
238
239 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
240
241 extern Elf_Dyn _DYNAMIC;
242 #pragma weak _DYNAMIC
243
244 int dlclose(void *) __exported;
245 char *dlerror(void) __exported;
246 void *dlopen(const char *, int) __exported;
247 void *fdlopen(int, int) __exported;
248 void *dlsym(void *, const char *) __exported;
249 dlfunc_t dlfunc(void *, const char *) __exported;
250 void *dlvsym(void *, const char *, const char *) __exported;
251 int dladdr(const void *, Dl_info *) __exported;
252 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
253 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
254 int dlinfo(void *, int , void *) __exported;
255 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
256 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
257 int _rtld_get_stack_prot(void) __exported;
258 int _rtld_is_dlopened(void *) __exported;
259 void _rtld_error(const char *, ...) __exported;
260
261 /* Only here to fix -Wmissing-prototypes warnings */
262 int __getosreldate(void);
263 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp);
264 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff);
265
266 int npagesizes;
267 static int osreldate;
268 size_t *pagesizes;
269 size_t page_size;
270
271 static int stack_prot = PROT_READ | PROT_WRITE | PROT_EXEC;
272 static int max_stack_flags;
273
274 /*
275 * Global declarations normally provided by crt1. The dynamic linker is
276 * not built with crt1, so we have to provide them ourselves.
277 */
278 char *__progname;
279 char **environ;
280
281 /*
282 * Used to pass argc, argv to init functions.
283 */
284 int main_argc;
285 char **main_argv;
286
287 /*
288 * Globals to control TLS allocation.
289 */
290 size_t tls_last_offset; /* Static TLS offset of last module */
291 size_t tls_last_size; /* Static TLS size of last module */
292 size_t tls_static_space; /* Static TLS space allocated */
293 static size_t tls_static_max_align;
294 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */
295 int tls_max_index = 1; /* Largest module index allocated */
296
297 static bool ld_library_path_rpath = false;
298 bool ld_fast_sigblock = false;
299
300 /*
301 * Globals for path names, and such
302 */
303 const char *ld_elf_hints_default = _PATH_ELF_HINTS;
304 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
305 const char *ld_path_rtld = _PATH_RTLD;
306 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
307 const char *ld_env_prefix = LD_;
308
309 static void (*rtld_exit_ptr)(void);
310
311 /*
312 * Fill in a DoneList with an allocation large enough to hold all of
313 * the currently-loaded objects. Keep this as a macro since it calls
314 * alloca and we want that to occur within the scope of the caller.
315 */
316 #define donelist_init(dlp) \
317 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
318 assert((dlp)->objs != NULL), \
319 (dlp)->num_alloc = obj_count, \
320 (dlp)->num_used = 0)
321
322 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
323 if (ld_utrace != NULL) \
324 ld_utrace_log(e, h, mb, ms, r, n); \
325 } while (0)
326
327 static void
ld_utrace_log(int event,void * handle,void * mapbase,size_t mapsize,int refcnt,const char * name)328 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
329 int refcnt, const char *name)
330 {
331 struct utrace_rtld ut;
332 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG;
333
334 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig));
335 ut.event = event;
336 ut.handle = handle;
337 ut.mapbase = mapbase;
338 ut.mapsize = mapsize;
339 ut.refcnt = refcnt;
340 bzero(ut.name, sizeof(ut.name));
341 if (name)
342 strlcpy(ut.name, name, sizeof(ut.name));
343 utrace(&ut, sizeof(ut));
344 }
345
346 enum {
347 LD_BIND_NOW = 0,
348 LD_PRELOAD,
349 LD_LIBMAP,
350 LD_LIBRARY_PATH,
351 LD_LIBRARY_PATH_FDS,
352 LD_LIBMAP_DISABLE,
353 LD_BIND_NOT,
354 LD_DEBUG,
355 LD_ELF_HINTS_PATH,
356 LD_LOADFLTR,
357 LD_LIBRARY_PATH_RPATH,
358 LD_PRELOAD_FDS,
359 LD_DYNAMIC_WEAK,
360 LD_TRACE_LOADED_OBJECTS,
361 LD_UTRACE,
362 LD_DUMP_REL_PRE,
363 LD_DUMP_REL_POST,
364 LD_TRACE_LOADED_OBJECTS_PROGNAME,
365 LD_TRACE_LOADED_OBJECTS_FMT1,
366 LD_TRACE_LOADED_OBJECTS_FMT2,
367 LD_TRACE_LOADED_OBJECTS_ALL,
368 LD_SHOW_AUXV,
369 LD_STATIC_TLS_EXTRA,
370 };
371
372 struct ld_env_var_desc {
373 const char * const n;
374 const char *val;
375 const bool unsecure;
376 };
377 #define LD_ENV_DESC(var, unsec) \
378 [LD_##var] = { .n = #var, .unsecure = unsec }
379
380 static struct ld_env_var_desc ld_env_vars[] = {
381 LD_ENV_DESC(BIND_NOW, false),
382 LD_ENV_DESC(PRELOAD, true),
383 LD_ENV_DESC(LIBMAP, true),
384 LD_ENV_DESC(LIBRARY_PATH, true),
385 LD_ENV_DESC(LIBRARY_PATH_FDS, true),
386 LD_ENV_DESC(LIBMAP_DISABLE, true),
387 LD_ENV_DESC(BIND_NOT, true),
388 LD_ENV_DESC(DEBUG, true),
389 LD_ENV_DESC(ELF_HINTS_PATH, true),
390 LD_ENV_DESC(LOADFLTR, true),
391 LD_ENV_DESC(LIBRARY_PATH_RPATH, true),
392 LD_ENV_DESC(PRELOAD_FDS, true),
393 LD_ENV_DESC(DYNAMIC_WEAK, true),
394 LD_ENV_DESC(TRACE_LOADED_OBJECTS, false),
395 LD_ENV_DESC(UTRACE, false),
396 LD_ENV_DESC(DUMP_REL_PRE, false),
397 LD_ENV_DESC(DUMP_REL_POST, false),
398 LD_ENV_DESC(TRACE_LOADED_OBJECTS_PROGNAME, false),
399 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT1, false),
400 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT2, false),
401 LD_ENV_DESC(TRACE_LOADED_OBJECTS_ALL, false),
402 LD_ENV_DESC(SHOW_AUXV, false),
403 LD_ENV_DESC(STATIC_TLS_EXTRA, false),
404 };
405
406 static const char *
ld_get_env_var(int idx)407 ld_get_env_var(int idx)
408 {
409 return (ld_env_vars[idx].val);
410 }
411
412 static const char *
rtld_get_env_val(char ** env,const char * name,size_t name_len)413 rtld_get_env_val(char **env, const char *name, size_t name_len)
414 {
415 char **m, *n, *v;
416
417 for (m = env; *m != NULL; m++) {
418 n = *m;
419 v = strchr(n, '=');
420 if (v == NULL) {
421 /* corrupt environment? */
422 continue;
423 }
424 if (v - n == (ptrdiff_t)name_len &&
425 strncmp(name, n, name_len) == 0)
426 return (v + 1);
427 }
428 return (NULL);
429 }
430
431 static void
rtld_init_env_vars_for_prefix(char ** env,const char * env_prefix)432 rtld_init_env_vars_for_prefix(char **env, const char *env_prefix)
433 {
434 struct ld_env_var_desc *lvd;
435 size_t prefix_len, nlen;
436 char **m, *n, *v;
437 int i;
438
439 prefix_len = strlen(env_prefix);
440 for (m = env; *m != NULL; m++) {
441 n = *m;
442 if (strncmp(env_prefix, n, prefix_len) != 0) {
443 /* Not a rtld environment variable. */
444 continue;
445 }
446 n += prefix_len;
447 v = strchr(n, '=');
448 if (v == NULL) {
449 /* corrupt environment? */
450 continue;
451 }
452 for (i = 0; i < (int)nitems(ld_env_vars); i++) {
453 lvd = &ld_env_vars[i];
454 if (lvd->val != NULL) {
455 /* Saw higher-priority variable name already. */
456 continue;
457 }
458 nlen = strlen(lvd->n);
459 if (v - n == (ptrdiff_t)nlen &&
460 strncmp(lvd->n, n, nlen) == 0) {
461 lvd->val = v + 1;
462 break;
463 }
464 }
465 }
466 }
467
468 static void
rtld_init_env_vars(char ** env)469 rtld_init_env_vars(char **env)
470 {
471 rtld_init_env_vars_for_prefix(env, ld_env_prefix);
472 }
473
474 static void
set_ld_elf_hints_path(void)475 set_ld_elf_hints_path(void)
476 {
477 if (ld_elf_hints_path == NULL || strlen(ld_elf_hints_path) == 0)
478 ld_elf_hints_path = ld_elf_hints_default;
479 }
480
481 uintptr_t
rtld_round_page(uintptr_t x)482 rtld_round_page(uintptr_t x)
483 {
484 return (roundup2(x, page_size));
485 }
486
487 uintptr_t
rtld_trunc_page(uintptr_t x)488 rtld_trunc_page(uintptr_t x)
489 {
490 return (rounddown2(x, page_size));
491 }
492
493 /*
494 * Main entry point for dynamic linking. The first argument is the
495 * stack pointer. The stack is expected to be laid out as described
496 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
497 * Specifically, the stack pointer points to a word containing
498 * ARGC. Following that in the stack is a null-terminated sequence
499 * of pointers to argument strings. Then comes a null-terminated
500 * sequence of pointers to environment strings. Finally, there is a
501 * sequence of "auxiliary vector" entries.
502 *
503 * The second argument points to a place to store the dynamic linker's
504 * exit procedure pointer and the third to a place to store the main
505 * program's object.
506 *
507 * The return value is the main program's entry point.
508 */
509 func_ptr_type
_rtld(Elf_Addr * sp,func_ptr_type * exit_proc,Obj_Entry ** objp)510 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
511 {
512 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT];
513 Objlist_Entry *entry;
514 Obj_Entry *last_interposer, *obj, *preload_tail;
515 const Elf_Phdr *phdr;
516 Objlist initlist;
517 RtldLockState lockstate;
518 struct stat st;
519 Elf_Addr *argcp;
520 char **argv, **env, **envp, *kexecpath;
521 const char *argv0, *binpath, *library_path_rpath, *static_tls_extra;
522 struct ld_env_var_desc *lvd;
523 caddr_t imgentry;
524 char buf[MAXPATHLEN];
525 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc;
526 size_t sz;
527 #ifdef __powerpc__
528 int old_auxv_format = 1;
529 #endif
530 bool dir_enable, dir_ignore, direct_exec, explicit_fd, search_in_path;
531
532 /*
533 * On entry, the dynamic linker itself has not been relocated yet.
534 * Be very careful not to reference any global data until after
535 * init_rtld has returned. It is OK to reference file-scope statics
536 * and string constants, and to call static and global functions.
537 */
538
539 /* Find the auxiliary vector on the stack. */
540 argcp = sp;
541 argc = *sp++;
542 argv = (char **) sp;
543 sp += argc + 1; /* Skip over arguments and NULL terminator */
544 env = (char **) sp;
545 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
546 ;
547 aux = (Elf_Auxinfo *) sp;
548
549 /* Digest the auxiliary vector. */
550 for (i = 0; i < AT_COUNT; i++)
551 aux_info[i] = NULL;
552 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
553 if (auxp->a_type < AT_COUNT)
554 aux_info[auxp->a_type] = auxp;
555 #ifdef __powerpc__
556 if (auxp->a_type == 23) /* AT_STACKPROT */
557 old_auxv_format = 0;
558 #endif
559 }
560
561 #ifdef __powerpc__
562 if (old_auxv_format) {
563 /* Remap from old-style auxv numbers. */
564 aux_info[23] = aux_info[21]; /* AT_STACKPROT */
565 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */
566 aux_info[19] = aux_info[17]; /* AT_NCPUS */
567 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */
568 aux_info[15] = aux_info[13]; /* AT_EXECPATH */
569 aux_info[13] = NULL; /* AT_GID */
570
571 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */
572 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */
573 aux_info[16] = aux_info[14]; /* AT_CANARY */
574 aux_info[14] = NULL; /* AT_EGID */
575 }
576 #endif
577
578 /* Initialize and relocate ourselves. */
579 assert(aux_info[AT_BASE] != NULL);
580 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
581
582 dlerror_dflt_init();
583
584 __progname = obj_rtld.path;
585 argv0 = argv[0] != NULL ? argv[0] : "(null)";
586 environ = env;
587 main_argc = argc;
588 main_argv = argv;
589
590 if (aux_info[AT_BSDFLAGS] != NULL &&
591 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0)
592 ld_fast_sigblock = true;
593
594 trust = !issetugid();
595 direct_exec = false;
596
597 md_abi_variant_hook(aux_info);
598 rtld_init_env_vars(env);
599
600 fd = -1;
601 if (aux_info[AT_EXECFD] != NULL) {
602 fd = aux_info[AT_EXECFD]->a_un.a_val;
603 } else {
604 assert(aux_info[AT_PHDR] != NULL);
605 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
606 if (phdr == obj_rtld.phdr) {
607 if (!trust) {
608 _rtld_error("Tainted process refusing to run binary %s",
609 argv0);
610 rtld_die();
611 }
612 direct_exec = true;
613
614 dbg("opening main program in direct exec mode");
615 if (argc >= 2) {
616 rtld_argc = parse_args(argv, argc, &search_in_path, &fd,
617 &argv0, &dir_ignore);
618 explicit_fd = (fd != -1);
619 binpath = NULL;
620 if (!explicit_fd)
621 fd = open_binary_fd(argv0, search_in_path, &binpath);
622 if (fstat(fd, &st) == -1) {
623 _rtld_error("Failed to fstat FD %d (%s): %s", fd,
624 explicit_fd ? "user-provided descriptor" : argv0,
625 rtld_strerror(errno));
626 rtld_die();
627 }
628
629 /*
630 * Rough emulation of the permission checks done by
631 * execve(2), only Unix DACs are checked, ACLs are
632 * ignored. Preserve the semantic of disabling owner
633 * to execute if owner x bit is cleared, even if
634 * others x bit is enabled.
635 * mmap(2) does not allow to mmap with PROT_EXEC if
636 * binary' file comes from noexec mount. We cannot
637 * set a text reference on the binary.
638 */
639 dir_enable = false;
640 if (st.st_uid == geteuid()) {
641 if ((st.st_mode & S_IXUSR) != 0)
642 dir_enable = true;
643 } else if (st.st_gid == getegid()) {
644 if ((st.st_mode & S_IXGRP) != 0)
645 dir_enable = true;
646 } else if ((st.st_mode & S_IXOTH) != 0) {
647 dir_enable = true;
648 }
649 if (!dir_enable && !dir_ignore) {
650 _rtld_error("No execute permission for binary %s",
651 argv0);
652 rtld_die();
653 }
654
655 /*
656 * For direct exec mode, argv[0] is the interpreter
657 * name, we must remove it and shift arguments left
658 * before invoking binary main. Since stack layout
659 * places environment pointers and aux vectors right
660 * after the terminating NULL, we must shift
661 * environment and aux as well.
662 */
663 main_argc = argc - rtld_argc;
664 for (i = 0; i <= main_argc; i++)
665 argv[i] = argv[i + rtld_argc];
666 *argcp -= rtld_argc;
667 environ = env = envp = argv + main_argc + 1;
668 dbg("move env from %p to %p", envp + rtld_argc, envp);
669 do {
670 *envp = *(envp + rtld_argc);
671 } while (*envp++ != NULL);
672 aux = auxp = (Elf_Auxinfo *)envp;
673 auxpf = (Elf_Auxinfo *)(envp + rtld_argc);
674 dbg("move aux from %p to %p", auxpf, aux);
675 /* XXXKIB insert place for AT_EXECPATH if not present */
676 for (;; auxp++, auxpf++) {
677 *auxp = *auxpf;
678 if (auxp->a_type == AT_NULL)
679 break;
680 }
681 /* Since the auxiliary vector has moved, redigest it. */
682 for (i = 0; i < AT_COUNT; i++)
683 aux_info[i] = NULL;
684 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
685 if (auxp->a_type < AT_COUNT)
686 aux_info[auxp->a_type] = auxp;
687 }
688
689 /* Point AT_EXECPATH auxv and aux_info to the binary path. */
690 if (binpath == NULL) {
691 aux_info[AT_EXECPATH] = NULL;
692 } else {
693 if (aux_info[AT_EXECPATH] == NULL) {
694 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo));
695 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH;
696 }
697 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *,
698 binpath);
699 }
700 } else {
701 _rtld_error("No binary");
702 rtld_die();
703 }
704 }
705 }
706
707 ld_bind_now = ld_get_env_var(LD_BIND_NOW);
708
709 /*
710 * If the process is tainted, then we un-set the dangerous environment
711 * variables. The process will be marked as tainted until setuid(2)
712 * is called. If any child process calls setuid(2) we do not want any
713 * future processes to honor the potentially un-safe variables.
714 */
715 if (!trust) {
716 for (i = 0; i < (int)nitems(ld_env_vars); i++) {
717 lvd = &ld_env_vars[i];
718 if (lvd->unsecure)
719 lvd->val = NULL;
720 }
721 }
722
723 ld_debug = ld_get_env_var(LD_DEBUG);
724 if (ld_bind_now == NULL)
725 ld_bind_not = ld_get_env_var(LD_BIND_NOT) != NULL;
726 ld_dynamic_weak = ld_get_env_var(LD_DYNAMIC_WEAK) == NULL;
727 libmap_disable = ld_get_env_var(LD_LIBMAP_DISABLE) != NULL;
728 libmap_override = ld_get_env_var(LD_LIBMAP);
729 ld_library_path = ld_get_env_var(LD_LIBRARY_PATH);
730 ld_library_dirs = ld_get_env_var(LD_LIBRARY_PATH_FDS);
731 ld_preload = ld_get_env_var(LD_PRELOAD);
732 ld_preload_fds = ld_get_env_var(LD_PRELOAD_FDS);
733 ld_elf_hints_path = ld_get_env_var(LD_ELF_HINTS_PATH);
734 ld_loadfltr = ld_get_env_var(LD_LOADFLTR) != NULL;
735 library_path_rpath = ld_get_env_var(LD_LIBRARY_PATH_RPATH);
736 if (library_path_rpath != NULL) {
737 if (library_path_rpath[0] == 'y' ||
738 library_path_rpath[0] == 'Y' ||
739 library_path_rpath[0] == '1')
740 ld_library_path_rpath = true;
741 else
742 ld_library_path_rpath = false;
743 }
744 static_tls_extra = ld_get_env_var(LD_STATIC_TLS_EXTRA);
745 if (static_tls_extra != NULL && static_tls_extra[0] != '\0') {
746 sz = parse_integer(static_tls_extra);
747 if (sz >= RTLD_STATIC_TLS_EXTRA && sz <= SIZE_T_MAX)
748 ld_static_tls_extra = sz;
749 }
750 dangerous_ld_env = libmap_disable || libmap_override != NULL ||
751 ld_library_path != NULL || ld_preload != NULL ||
752 ld_elf_hints_path != NULL || ld_loadfltr || !ld_dynamic_weak ||
753 static_tls_extra != NULL;
754 ld_tracing = ld_get_env_var(LD_TRACE_LOADED_OBJECTS);
755 ld_utrace = ld_get_env_var(LD_UTRACE);
756
757 set_ld_elf_hints_path();
758 if (ld_debug != NULL && *ld_debug != '\0')
759 debug = 1;
760 dbg("%s is initialized, base address = %p", __progname,
761 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
762 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
763 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
764
765 dbg("initializing thread locks");
766 lockdflt_init();
767
768 /*
769 * Load the main program, or process its program header if it is
770 * already loaded.
771 */
772 if (fd != -1) { /* Load the main program. */
773 dbg("loading main program");
774 obj_main = map_object(fd, argv0, NULL);
775 close(fd);
776 if (obj_main == NULL)
777 rtld_die();
778 max_stack_flags = obj_main->stack_flags;
779 } else { /* Main program already loaded. */
780 dbg("processing main program's program header");
781 assert(aux_info[AT_PHDR] != NULL);
782 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
783 assert(aux_info[AT_PHNUM] != NULL);
784 phnum = aux_info[AT_PHNUM]->a_un.a_val;
785 assert(aux_info[AT_PHENT] != NULL);
786 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
787 assert(aux_info[AT_ENTRY] != NULL);
788 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
789 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL)
790 rtld_die();
791 }
792
793 if (aux_info[AT_EXECPATH] != NULL && fd == -1) {
794 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
795 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
796 if (kexecpath[0] == '/')
797 obj_main->path = kexecpath;
798 else if (getcwd(buf, sizeof(buf)) == NULL ||
799 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
800 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
801 obj_main->path = xstrdup(argv0);
802 else
803 obj_main->path = xstrdup(buf);
804 } else {
805 dbg("No AT_EXECPATH or direct exec");
806 obj_main->path = xstrdup(argv0);
807 }
808 dbg("obj_main path %s", obj_main->path);
809 obj_main->mainprog = true;
810
811 if (aux_info[AT_STACKPROT] != NULL &&
812 aux_info[AT_STACKPROT]->a_un.a_val != 0)
813 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
814
815 #ifndef COMPAT_libcompat
816 /*
817 * Get the actual dynamic linker pathname from the executable if
818 * possible. (It should always be possible.) That ensures that
819 * gdb will find the right dynamic linker even if a non-standard
820 * one is being used.
821 */
822 if (obj_main->interp != NULL &&
823 strcmp(obj_main->interp, obj_rtld.path) != 0) {
824 free(obj_rtld.path);
825 obj_rtld.path = xstrdup(obj_main->interp);
826 __progname = obj_rtld.path;
827 }
828 #endif
829
830 if (!digest_dynamic(obj_main, 0))
831 rtld_die();
832 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
833 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
834 obj_main->dynsymcount);
835
836 linkmap_add(obj_main);
837 linkmap_add(&obj_rtld);
838
839 /* Link the main program into the list of objects. */
840 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
841 obj_count++;
842 obj_loads++;
843
844 /* Initialize a fake symbol for resolving undefined weak references. */
845 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
846 sym_zero.st_shndx = SHN_UNDEF;
847 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
848
849 if (!libmap_disable)
850 libmap_disable = (bool)lm_init(libmap_override);
851
852 if (aux_info[AT_KPRELOAD] != NULL &&
853 aux_info[AT_KPRELOAD]->a_un.a_ptr != NULL) {
854 dbg("loading kernel vdso");
855 if (load_kpreload(aux_info[AT_KPRELOAD]->a_un.a_ptr) == -1)
856 rtld_die();
857 }
858
859 dbg("loading LD_PRELOAD_FDS libraries");
860 if (load_preload_objects(ld_preload_fds, true) == -1)
861 rtld_die();
862
863 dbg("loading LD_PRELOAD libraries");
864 if (load_preload_objects(ld_preload, false) == -1)
865 rtld_die();
866 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
867
868 dbg("loading needed objects");
869 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE :
870 0) == -1)
871 rtld_die();
872
873 /* Make a list of all objects loaded at startup. */
874 last_interposer = obj_main;
875 TAILQ_FOREACH(obj, &obj_list, next) {
876 if (obj->marker)
877 continue;
878 if (obj->z_interpose && obj != obj_main) {
879 objlist_put_after(&list_main, last_interposer, obj);
880 last_interposer = obj;
881 } else {
882 objlist_push_tail(&list_main, obj);
883 }
884 obj->refcount++;
885 }
886
887 dbg("checking for required versions");
888 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
889 rtld_die();
890
891 if (ld_get_env_var(LD_SHOW_AUXV) != NULL)
892 dump_auxv(aux_info);
893
894 if (ld_tracing) { /* We're done */
895 trace_loaded_objects(obj_main, true);
896 exit(0);
897 }
898
899 if (ld_get_env_var(LD_DUMP_REL_PRE) != NULL) {
900 dump_relocations(obj_main);
901 exit (0);
902 }
903
904 /*
905 * Processing tls relocations requires having the tls offsets
906 * initialized. Prepare offsets before starting initial
907 * relocation processing.
908 */
909 dbg("initializing initial thread local storage offsets");
910 STAILQ_FOREACH(entry, &list_main, link) {
911 /*
912 * Allocate all the initial objects out of the static TLS
913 * block even if they didn't ask for it.
914 */
915 allocate_tls_offset(entry->obj);
916 }
917
918 if (relocate_objects(obj_main,
919 ld_bind_now != NULL && *ld_bind_now != '\0',
920 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
921 rtld_die();
922
923 dbg("doing copy relocations");
924 if (do_copy_relocations(obj_main) == -1)
925 rtld_die();
926
927 if (ld_get_env_var(LD_DUMP_REL_POST) != NULL) {
928 dump_relocations(obj_main);
929 exit (0);
930 }
931
932 ifunc_init(aux);
933
934 /*
935 * Setup TLS for main thread. This must be done after the
936 * relocations are processed, since tls initialization section
937 * might be the subject for relocations.
938 */
939 dbg("initializing initial thread local storage");
940 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
941
942 dbg("initializing key program variables");
943 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
944 set_program_var("environ", env);
945 set_program_var("__elf_aux_vector", aux);
946
947 /* Make a list of init functions to call. */
948 objlist_init(&initlist);
949 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)),
950 preload_tail, &initlist);
951
952 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
953
954 map_stacks_exec(NULL);
955
956 if (!obj_main->crt_no_init) {
957 /*
958 * Make sure we don't call the main program's init and fini
959 * functions for binaries linked with old crt1 which calls
960 * _init itself.
961 */
962 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
963 obj_main->preinit_array = obj_main->init_array =
964 obj_main->fini_array = (Elf_Addr)NULL;
965 }
966
967 if (direct_exec) {
968 /* Set osrel for direct-execed binary */
969 mib[0] = CTL_KERN;
970 mib[1] = KERN_PROC;
971 mib[2] = KERN_PROC_OSREL;
972 mib[3] = getpid();
973 osrel = obj_main->osrel;
974 sz = sizeof(old_osrel);
975 dbg("setting osrel to %d", osrel);
976 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel));
977 }
978
979 wlock_acquire(rtld_bind_lock, &lockstate);
980
981 dbg("resolving ifuncs");
982 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL &&
983 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1)
984 rtld_die();
985
986 rtld_exit_ptr = rtld_exit;
987 if (obj_main->crt_no_init)
988 preinit_main();
989 objlist_call_init(&initlist, &lockstate);
990 _r_debug_postinit(&obj_main->linkmap);
991 objlist_clear(&initlist);
992 dbg("loading filtees");
993 TAILQ_FOREACH(obj, &obj_list, next) {
994 if (obj->marker)
995 continue;
996 if (ld_loadfltr || obj->z_loadfltr)
997 load_filtees(obj, 0, &lockstate);
998 }
999
1000 dbg("enforcing main obj relro");
1001 if (obj_enforce_relro(obj_main) == -1)
1002 rtld_die();
1003
1004 lock_release(rtld_bind_lock, &lockstate);
1005
1006 dbg("transferring control to program entry point = %p", obj_main->entry);
1007
1008 /* Return the exit procedure and the program entry point. */
1009 *exit_proc = rtld_exit_ptr;
1010 *objp = obj_main;
1011 return ((func_ptr_type)obj_main->entry);
1012 }
1013
1014 void *
rtld_resolve_ifunc(const Obj_Entry * obj,const Elf_Sym * def)1015 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
1016 {
1017 void *ptr;
1018 Elf_Addr target;
1019
1020 ptr = (void *)make_function_pointer(def, obj);
1021 target = call_ifunc_resolver(ptr);
1022 return ((void *)target);
1023 }
1024
1025 Elf_Addr
_rtld_bind(Obj_Entry * obj,Elf_Size reloff)1026 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
1027 {
1028 const Elf_Rel *rel;
1029 const Elf_Sym *def;
1030 const Obj_Entry *defobj;
1031 Elf_Addr *where;
1032 Elf_Addr target;
1033 RtldLockState lockstate;
1034
1035 rlock_acquire(rtld_bind_lock, &lockstate);
1036 if (sigsetjmp(lockstate.env, 0) != 0)
1037 lock_upgrade(rtld_bind_lock, &lockstate);
1038 if (obj->pltrel)
1039 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff);
1040 else
1041 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff);
1042
1043 where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
1044 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
1045 NULL, &lockstate);
1046 if (def == NULL)
1047 rtld_die();
1048 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
1049 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
1050 else
1051 target = (Elf_Addr)(defobj->relocbase + def->st_value);
1052
1053 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
1054 defobj->strtab + def->st_name,
1055 obj->path == NULL ? NULL : basename(obj->path),
1056 (void *)target,
1057 defobj->path == NULL ? NULL : basename(defobj->path));
1058
1059 /*
1060 * Write the new contents for the jmpslot. Note that depending on
1061 * architecture, the value which we need to return back to the
1062 * lazy binding trampoline may or may not be the target
1063 * address. The value returned from reloc_jmpslot() is the value
1064 * that the trampoline needs.
1065 */
1066 target = reloc_jmpslot(where, target, defobj, obj, rel);
1067 lock_release(rtld_bind_lock, &lockstate);
1068 return (target);
1069 }
1070
1071 /*
1072 * Error reporting function. Use it like printf. If formats the message
1073 * into a buffer, and sets things up so that the next call to dlerror()
1074 * will return the message.
1075 */
1076 void
_rtld_error(const char * fmt,...)1077 _rtld_error(const char *fmt, ...)
1078 {
1079 va_list ap;
1080
1081 va_start(ap, fmt);
1082 rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz,
1083 fmt, ap);
1084 va_end(ap);
1085 *lockinfo.dlerror_seen() = 0;
1086 dbg("rtld_error: %s", lockinfo.dlerror_loc());
1087 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc());
1088 }
1089
1090 /*
1091 * Return a dynamically-allocated copy of the current error message, if any.
1092 */
1093 static struct dlerror_save *
errmsg_save(void)1094 errmsg_save(void)
1095 {
1096 struct dlerror_save *res;
1097
1098 res = xmalloc(sizeof(*res));
1099 res->seen = *lockinfo.dlerror_seen();
1100 if (res->seen == 0)
1101 res->msg = xstrdup(lockinfo.dlerror_loc());
1102 return (res);
1103 }
1104
1105 /*
1106 * Restore the current error message from a copy which was previously saved
1107 * by errmsg_save(). The copy is freed.
1108 */
1109 static void
errmsg_restore(struct dlerror_save * saved_msg)1110 errmsg_restore(struct dlerror_save *saved_msg)
1111 {
1112 if (saved_msg == NULL || saved_msg->seen == 1) {
1113 *lockinfo.dlerror_seen() = 1;
1114 } else {
1115 *lockinfo.dlerror_seen() = 0;
1116 strlcpy(lockinfo.dlerror_loc(), saved_msg->msg,
1117 lockinfo.dlerror_loc_sz);
1118 free(saved_msg->msg);
1119 }
1120 free(saved_msg);
1121 }
1122
1123 static const char *
basename(const char * name)1124 basename(const char *name)
1125 {
1126 const char *p;
1127
1128 p = strrchr(name, '/');
1129 return (p != NULL ? p + 1 : name);
1130 }
1131
1132 static struct utsname uts;
1133
1134 static char *
origin_subst_one(Obj_Entry * obj,char * real,const char * kw,const char * subst,bool may_free)1135 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
1136 const char *subst, bool may_free)
1137 {
1138 char *p, *p1, *res, *resp;
1139 int subst_len, kw_len, subst_count, old_len, new_len;
1140
1141 kw_len = strlen(kw);
1142
1143 /*
1144 * First, count the number of the keyword occurrences, to
1145 * preallocate the final string.
1146 */
1147 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
1148 p1 = strstr(p, kw);
1149 if (p1 == NULL)
1150 break;
1151 }
1152
1153 /*
1154 * If the keyword is not found, just return.
1155 *
1156 * Return non-substituted string if resolution failed. We
1157 * cannot do anything more reasonable, the failure mode of the
1158 * caller is unresolved library anyway.
1159 */
1160 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
1161 return (may_free ? real : xstrdup(real));
1162 if (obj != NULL)
1163 subst = obj->origin_path;
1164
1165 /*
1166 * There is indeed something to substitute. Calculate the
1167 * length of the resulting string, and allocate it.
1168 */
1169 subst_len = strlen(subst);
1170 old_len = strlen(real);
1171 new_len = old_len + (subst_len - kw_len) * subst_count;
1172 res = xmalloc(new_len + 1);
1173
1174 /*
1175 * Now, execute the substitution loop.
1176 */
1177 for (p = real, resp = res, *resp = '\0';;) {
1178 p1 = strstr(p, kw);
1179 if (p1 != NULL) {
1180 /* Copy the prefix before keyword. */
1181 memcpy(resp, p, p1 - p);
1182 resp += p1 - p;
1183 /* Keyword replacement. */
1184 memcpy(resp, subst, subst_len);
1185 resp += subst_len;
1186 *resp = '\0';
1187 p = p1 + kw_len;
1188 } else
1189 break;
1190 }
1191
1192 /* Copy to the end of string and finish. */
1193 strcat(resp, p);
1194 if (may_free)
1195 free(real);
1196 return (res);
1197 }
1198
1199 static const struct {
1200 const char *kw;
1201 bool pass_obj;
1202 const char *subst;
1203 } tokens[] = {
1204 { .kw = "$ORIGIN", .pass_obj = true, .subst = NULL },
1205 { .kw = "${ORIGIN}", .pass_obj = true, .subst = NULL },
1206 { .kw = "$OSNAME", .pass_obj = false, .subst = uts.sysname },
1207 { .kw = "${OSNAME}", .pass_obj = false, .subst = uts.sysname },
1208 { .kw = "$OSREL", .pass_obj = false, .subst = uts.release },
1209 { .kw = "${OSREL}", .pass_obj = false, .subst = uts.release },
1210 { .kw = "$PLATFORM", .pass_obj = false, .subst = uts.machine },
1211 { .kw = "${PLATFORM}", .pass_obj = false, .subst = uts.machine },
1212 { .kw = "$LIB", .pass_obj = false, .subst = TOKEN_LIB },
1213 { .kw = "${LIB}", .pass_obj = false, .subst = TOKEN_LIB },
1214 };
1215
1216 static char *
origin_subst(Obj_Entry * obj,const char * real)1217 origin_subst(Obj_Entry *obj, const char *real)
1218 {
1219 char *res;
1220 int i;
1221
1222 if (obj == NULL || !trust)
1223 return (xstrdup(real));
1224 if (uts.sysname[0] == '\0') {
1225 if (uname(&uts) != 0) {
1226 _rtld_error("utsname failed: %d", errno);
1227 return (NULL);
1228 }
1229 }
1230
1231 /* __DECONST is safe here since without may_free real is unchanged */
1232 res = __DECONST(char *, real);
1233 for (i = 0; i < (int)nitems(tokens); i++) {
1234 res = origin_subst_one(tokens[i].pass_obj ? obj : NULL,
1235 res, tokens[i].kw, tokens[i].subst, i != 0);
1236 }
1237 return (res);
1238 }
1239
1240 void
rtld_die(void)1241 rtld_die(void)
1242 {
1243 const char *msg = dlerror();
1244
1245 if (msg == NULL)
1246 msg = "Fatal error";
1247 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": ");
1248 rtld_fdputstr(STDERR_FILENO, msg);
1249 rtld_fdputchar(STDERR_FILENO, '\n');
1250 _exit(1);
1251 }
1252
1253 /*
1254 * Process a shared object's DYNAMIC section, and save the important
1255 * information in its Obj_Entry structure.
1256 */
1257 static void
digest_dynamic1(Obj_Entry * obj,int early,const Elf_Dyn ** dyn_rpath,const Elf_Dyn ** dyn_soname,const Elf_Dyn ** dyn_runpath)1258 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
1259 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
1260 {
1261 const Elf_Dyn *dynp;
1262 Needed_Entry **needed_tail = &obj->needed;
1263 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
1264 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
1265 const Elf_Hashelt *hashtab;
1266 const Elf32_Word *hashval;
1267 Elf32_Word bkt, nmaskwords;
1268 int bloom_size32;
1269 int plttype = DT_REL;
1270
1271 *dyn_rpath = NULL;
1272 *dyn_soname = NULL;
1273 *dyn_runpath = NULL;
1274
1275 obj->bind_now = false;
1276 dynp = obj->dynamic;
1277 if (dynp == NULL)
1278 return;
1279 for (; dynp->d_tag != DT_NULL; dynp++) {
1280 switch (dynp->d_tag) {
1281
1282 case DT_REL:
1283 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr);
1284 break;
1285
1286 case DT_RELSZ:
1287 obj->relsize = dynp->d_un.d_val;
1288 break;
1289
1290 case DT_RELENT:
1291 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1292 break;
1293
1294 case DT_JMPREL:
1295 obj->pltrel = (const Elf_Rel *)
1296 (obj->relocbase + dynp->d_un.d_ptr);
1297 break;
1298
1299 case DT_PLTRELSZ:
1300 obj->pltrelsize = dynp->d_un.d_val;
1301 break;
1302
1303 case DT_RELA:
1304 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr);
1305 break;
1306
1307 case DT_RELASZ:
1308 obj->relasize = dynp->d_un.d_val;
1309 break;
1310
1311 case DT_RELAENT:
1312 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1313 break;
1314
1315 case DT_RELR:
1316 obj->relr = (const Elf_Relr *)(obj->relocbase + dynp->d_un.d_ptr);
1317 break;
1318
1319 case DT_RELRSZ:
1320 obj->relrsize = dynp->d_un.d_val;
1321 break;
1322
1323 case DT_RELRENT:
1324 assert(dynp->d_un.d_val == sizeof(Elf_Relr));
1325 break;
1326
1327 case DT_PLTREL:
1328 plttype = dynp->d_un.d_val;
1329 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1330 break;
1331
1332 case DT_SYMTAB:
1333 obj->symtab = (const Elf_Sym *)
1334 (obj->relocbase + dynp->d_un.d_ptr);
1335 break;
1336
1337 case DT_SYMENT:
1338 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1339 break;
1340
1341 case DT_STRTAB:
1342 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr);
1343 break;
1344
1345 case DT_STRSZ:
1346 obj->strsize = dynp->d_un.d_val;
1347 break;
1348
1349 case DT_VERNEED:
1350 obj->verneed = (const Elf_Verneed *)(obj->relocbase +
1351 dynp->d_un.d_val);
1352 break;
1353
1354 case DT_VERNEEDNUM:
1355 obj->verneednum = dynp->d_un.d_val;
1356 break;
1357
1358 case DT_VERDEF:
1359 obj->verdef = (const Elf_Verdef *)(obj->relocbase +
1360 dynp->d_un.d_val);
1361 break;
1362
1363 case DT_VERDEFNUM:
1364 obj->verdefnum = dynp->d_un.d_val;
1365 break;
1366
1367 case DT_VERSYM:
1368 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1369 dynp->d_un.d_val);
1370 break;
1371
1372 case DT_HASH:
1373 {
1374 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1375 dynp->d_un.d_ptr);
1376 obj->nbuckets = hashtab[0];
1377 obj->nchains = hashtab[1];
1378 obj->buckets = hashtab + 2;
1379 obj->chains = obj->buckets + obj->nbuckets;
1380 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1381 obj->buckets != NULL;
1382 }
1383 break;
1384
1385 case DT_GNU_HASH:
1386 {
1387 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1388 dynp->d_un.d_ptr);
1389 obj->nbuckets_gnu = hashtab[0];
1390 obj->symndx_gnu = hashtab[1];
1391 nmaskwords = hashtab[2];
1392 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1393 obj->maskwords_bm_gnu = nmaskwords - 1;
1394 obj->shift2_gnu = hashtab[3];
1395 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4);
1396 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1397 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1398 obj->symndx_gnu;
1399 /* Number of bitmask words is required to be power of 2 */
1400 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1401 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1402 }
1403 break;
1404
1405 case DT_NEEDED:
1406 if (!obj->rtld) {
1407 Needed_Entry *nep = NEW(Needed_Entry);
1408 nep->name = dynp->d_un.d_val;
1409 nep->obj = NULL;
1410 nep->next = NULL;
1411
1412 *needed_tail = nep;
1413 needed_tail = &nep->next;
1414 }
1415 break;
1416
1417 case DT_FILTER:
1418 if (!obj->rtld) {
1419 Needed_Entry *nep = NEW(Needed_Entry);
1420 nep->name = dynp->d_un.d_val;
1421 nep->obj = NULL;
1422 nep->next = NULL;
1423
1424 *needed_filtees_tail = nep;
1425 needed_filtees_tail = &nep->next;
1426
1427 if (obj->linkmap.l_refname == NULL)
1428 obj->linkmap.l_refname = (char *)dynp->d_un.d_val;
1429 }
1430 break;
1431
1432 case DT_AUXILIARY:
1433 if (!obj->rtld) {
1434 Needed_Entry *nep = NEW(Needed_Entry);
1435 nep->name = dynp->d_un.d_val;
1436 nep->obj = NULL;
1437 nep->next = NULL;
1438
1439 *needed_aux_filtees_tail = nep;
1440 needed_aux_filtees_tail = &nep->next;
1441 }
1442 break;
1443
1444 case DT_PLTGOT:
1445 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr);
1446 break;
1447
1448 case DT_TEXTREL:
1449 obj->textrel = true;
1450 break;
1451
1452 case DT_SYMBOLIC:
1453 obj->symbolic = true;
1454 break;
1455
1456 case DT_RPATH:
1457 /*
1458 * We have to wait until later to process this, because we
1459 * might not have gotten the address of the string table yet.
1460 */
1461 *dyn_rpath = dynp;
1462 break;
1463
1464 case DT_SONAME:
1465 *dyn_soname = dynp;
1466 break;
1467
1468 case DT_RUNPATH:
1469 *dyn_runpath = dynp;
1470 break;
1471
1472 case DT_INIT:
1473 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1474 break;
1475
1476 case DT_PREINIT_ARRAY:
1477 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1478 break;
1479
1480 case DT_PREINIT_ARRAYSZ:
1481 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1482 break;
1483
1484 case DT_INIT_ARRAY:
1485 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1486 break;
1487
1488 case DT_INIT_ARRAYSZ:
1489 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1490 break;
1491
1492 case DT_FINI:
1493 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1494 break;
1495
1496 case DT_FINI_ARRAY:
1497 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1498 break;
1499
1500 case DT_FINI_ARRAYSZ:
1501 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1502 break;
1503
1504 case DT_DEBUG:
1505 if (!early)
1506 dbg("Filling in DT_DEBUG entry");
1507 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug;
1508 break;
1509
1510 case DT_FLAGS:
1511 if (dynp->d_un.d_val & DF_ORIGIN)
1512 obj->z_origin = true;
1513 if (dynp->d_un.d_val & DF_SYMBOLIC)
1514 obj->symbolic = true;
1515 if (dynp->d_un.d_val & DF_TEXTREL)
1516 obj->textrel = true;
1517 if (dynp->d_un.d_val & DF_BIND_NOW)
1518 obj->bind_now = true;
1519 if (dynp->d_un.d_val & DF_STATIC_TLS)
1520 obj->static_tls = true;
1521 break;
1522
1523 case DT_FLAGS_1:
1524 if (dynp->d_un.d_val & DF_1_NOOPEN)
1525 obj->z_noopen = true;
1526 if (dynp->d_un.d_val & DF_1_ORIGIN)
1527 obj->z_origin = true;
1528 if (dynp->d_un.d_val & DF_1_GLOBAL)
1529 obj->z_global = true;
1530 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1531 obj->bind_now = true;
1532 if (dynp->d_un.d_val & DF_1_NODELETE)
1533 obj->z_nodelete = true;
1534 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1535 obj->z_loadfltr = true;
1536 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1537 obj->z_interpose = true;
1538 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1539 obj->z_nodeflib = true;
1540 if (dynp->d_un.d_val & DF_1_PIE)
1541 obj->z_pie = true;
1542 break;
1543
1544 default:
1545 if (arch_digest_dynamic(obj, dynp))
1546 break;
1547
1548 if (!early) {
1549 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1550 (long)dynp->d_tag);
1551 }
1552 break;
1553 }
1554 }
1555
1556 obj->traced = false;
1557
1558 if (plttype == DT_RELA) {
1559 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1560 obj->pltrel = NULL;
1561 obj->pltrelasize = obj->pltrelsize;
1562 obj->pltrelsize = 0;
1563 }
1564
1565 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1566 if (obj->valid_hash_sysv)
1567 obj->dynsymcount = obj->nchains;
1568 else if (obj->valid_hash_gnu) {
1569 obj->dynsymcount = 0;
1570 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1571 if (obj->buckets_gnu[bkt] == 0)
1572 continue;
1573 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1574 do
1575 obj->dynsymcount++;
1576 while ((*hashval++ & 1u) == 0);
1577 }
1578 obj->dynsymcount += obj->symndx_gnu;
1579 }
1580
1581 if (obj->linkmap.l_refname != NULL)
1582 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj->
1583 linkmap.l_refname;
1584 }
1585
1586 static bool
obj_resolve_origin(Obj_Entry * obj)1587 obj_resolve_origin(Obj_Entry *obj)
1588 {
1589
1590 if (obj->origin_path != NULL)
1591 return (true);
1592 obj->origin_path = xmalloc(PATH_MAX);
1593 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1594 }
1595
1596 static bool
digest_dynamic2(Obj_Entry * obj,const Elf_Dyn * dyn_rpath,const Elf_Dyn * dyn_soname,const Elf_Dyn * dyn_runpath)1597 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1598 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1599 {
1600
1601 if (obj->z_origin && !obj_resolve_origin(obj))
1602 return (false);
1603
1604 if (dyn_runpath != NULL) {
1605 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val;
1606 obj->runpath = origin_subst(obj, obj->runpath);
1607 } else if (dyn_rpath != NULL) {
1608 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val;
1609 obj->rpath = origin_subst(obj, obj->rpath);
1610 }
1611 if (dyn_soname != NULL)
1612 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1613 return (true);
1614 }
1615
1616 static bool
digest_dynamic(Obj_Entry * obj,int early)1617 digest_dynamic(Obj_Entry *obj, int early)
1618 {
1619 const Elf_Dyn *dyn_rpath;
1620 const Elf_Dyn *dyn_soname;
1621 const Elf_Dyn *dyn_runpath;
1622
1623 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1624 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath));
1625 }
1626
1627 /*
1628 * Process a shared object's program header. This is used only for the
1629 * main program, when the kernel has already loaded the main program
1630 * into memory before calling the dynamic linker. It creates and
1631 * returns an Obj_Entry structure.
1632 */
1633 static Obj_Entry *
digest_phdr(const Elf_Phdr * phdr,int phnum,caddr_t entry,const char * path)1634 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1635 {
1636 Obj_Entry *obj;
1637 const Elf_Phdr *phlimit = phdr + phnum;
1638 const Elf_Phdr *ph;
1639 Elf_Addr note_start, note_end;
1640 int nsegs = 0;
1641
1642 obj = obj_new();
1643 for (ph = phdr; ph < phlimit; ph++) {
1644 if (ph->p_type != PT_PHDR)
1645 continue;
1646
1647 obj->phdr = phdr;
1648 obj->phsize = ph->p_memsz;
1649 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr;
1650 break;
1651 }
1652
1653 obj->stack_flags = PF_X | PF_R | PF_W;
1654
1655 for (ph = phdr; ph < phlimit; ph++) {
1656 switch (ph->p_type) {
1657
1658 case PT_INTERP:
1659 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1660 break;
1661
1662 case PT_LOAD:
1663 if (nsegs == 0) { /* First load segment */
1664 obj->vaddrbase = rtld_trunc_page(ph->p_vaddr);
1665 obj->mapbase = obj->vaddrbase + obj->relocbase;
1666 } else { /* Last load segment */
1667 obj->mapsize = rtld_round_page(ph->p_vaddr + ph->p_memsz) -
1668 obj->vaddrbase;
1669 }
1670 nsegs++;
1671 break;
1672
1673 case PT_DYNAMIC:
1674 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1675 break;
1676
1677 case PT_TLS:
1678 obj->tlsindex = 1;
1679 obj->tlssize = ph->p_memsz;
1680 obj->tlsalign = ph->p_align;
1681 obj->tlsinitsize = ph->p_filesz;
1682 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1683 obj->tlspoffset = ph->p_offset;
1684 break;
1685
1686 case PT_GNU_STACK:
1687 obj->stack_flags = ph->p_flags;
1688 break;
1689
1690 case PT_GNU_RELRO:
1691 obj->relro_page = obj->relocbase + rtld_trunc_page(ph->p_vaddr);
1692 obj->relro_size = rtld_trunc_page(ph->p_vaddr + ph->p_memsz) -
1693 rtld_trunc_page(ph->p_vaddr);
1694 break;
1695
1696 case PT_NOTE:
1697 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1698 note_end = note_start + ph->p_filesz;
1699 digest_notes(obj, note_start, note_end);
1700 break;
1701 }
1702 }
1703 if (nsegs < 1) {
1704 _rtld_error("%s: too few PT_LOAD segments", path);
1705 return (NULL);
1706 }
1707
1708 obj->entry = entry;
1709 return (obj);
1710 }
1711
1712 void
digest_notes(Obj_Entry * obj,Elf_Addr note_start,Elf_Addr note_end)1713 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1714 {
1715 const Elf_Note *note;
1716 const char *note_name;
1717 uintptr_t p;
1718
1719 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1720 note = (const Elf_Note *)((const char *)(note + 1) +
1721 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1722 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1723 if (arch_digest_note(obj, note))
1724 continue;
1725
1726 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1727 note->n_descsz != sizeof(int32_t))
1728 continue;
1729 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1730 note->n_type != NT_FREEBSD_FEATURE_CTL &&
1731 note->n_type != NT_FREEBSD_NOINIT_TAG)
1732 continue;
1733 note_name = (const char *)(note + 1);
1734 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1735 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1736 continue;
1737 switch (note->n_type) {
1738 case NT_FREEBSD_ABI_TAG:
1739 /* FreeBSD osrel note */
1740 p = (uintptr_t)(note + 1);
1741 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1742 obj->osrel = *(const int32_t *)(p);
1743 dbg("note osrel %d", obj->osrel);
1744 break;
1745 case NT_FREEBSD_FEATURE_CTL:
1746 /* FreeBSD ABI feature control note */
1747 p = (uintptr_t)(note + 1);
1748 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1749 obj->fctl0 = *(const uint32_t *)(p);
1750 dbg("note fctl0 %#x", obj->fctl0);
1751 break;
1752 case NT_FREEBSD_NOINIT_TAG:
1753 /* FreeBSD 'crt does not call init' note */
1754 obj->crt_no_init = true;
1755 dbg("note crt_no_init");
1756 break;
1757 }
1758 }
1759 }
1760
1761 static Obj_Entry *
dlcheck(void * handle)1762 dlcheck(void *handle)
1763 {
1764 Obj_Entry *obj;
1765
1766 TAILQ_FOREACH(obj, &obj_list, next) {
1767 if (obj == (Obj_Entry *) handle)
1768 break;
1769 }
1770
1771 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1772 _rtld_error("Invalid shared object handle %p", handle);
1773 return (NULL);
1774 }
1775 return (obj);
1776 }
1777
1778 /*
1779 * If the given object is already in the donelist, return true. Otherwise
1780 * add the object to the list and return false.
1781 */
1782 static bool
donelist_check(DoneList * dlp,const Obj_Entry * obj)1783 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1784 {
1785 unsigned int i;
1786
1787 for (i = 0; i < dlp->num_used; i++)
1788 if (dlp->objs[i] == obj)
1789 return (true);
1790 /*
1791 * Our donelist allocation should always be sufficient. But if
1792 * our threads locking isn't working properly, more shared objects
1793 * could have been loaded since we allocated the list. That should
1794 * never happen, but we'll handle it properly just in case it does.
1795 */
1796 if (dlp->num_used < dlp->num_alloc)
1797 dlp->objs[dlp->num_used++] = obj;
1798 return (false);
1799 }
1800
1801 /*
1802 * SysV hash function for symbol table lookup. It is a slightly optimized
1803 * version of the hash specified by the System V ABI.
1804 */
1805 Elf32_Word
elf_hash(const char * name)1806 elf_hash(const char *name)
1807 {
1808 const unsigned char *p = (const unsigned char *)name;
1809 Elf32_Word h = 0;
1810
1811 while (*p != '\0') {
1812 h = (h << 4) + *p++;
1813 h ^= (h >> 24) & 0xf0;
1814 }
1815 return (h & 0x0fffffff);
1816 }
1817
1818 /*
1819 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1820 * unsigned in case it's implemented with a wider type.
1821 */
1822 static uint32_t
gnu_hash(const char * s)1823 gnu_hash(const char *s)
1824 {
1825 uint32_t h;
1826 unsigned char c;
1827
1828 h = 5381;
1829 for (c = *s; c != '\0'; c = *++s)
1830 h = h * 33 + c;
1831 return (h & 0xffffffff);
1832 }
1833
1834
1835 /*
1836 * Find the library with the given name, and return its full pathname.
1837 * The returned string is dynamically allocated. Generates an error
1838 * message and returns NULL if the library cannot be found.
1839 *
1840 * If the second argument is non-NULL, then it refers to an already-
1841 * loaded shared object, whose library search path will be searched.
1842 *
1843 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1844 * descriptor (which is close-on-exec) will be passed out via the third
1845 * argument.
1846 *
1847 * The search order is:
1848 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1849 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1850 * LD_LIBRARY_PATH
1851 * DT_RUNPATH in the referencing file
1852 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1853 * from list)
1854 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1855 *
1856 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1857 */
1858 static char *
find_library(const char * xname,const Obj_Entry * refobj,int * fdp)1859 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1860 {
1861 char *pathname, *refobj_path;
1862 const char *name;
1863 bool nodeflib, objgiven;
1864
1865 objgiven = refobj != NULL;
1866
1867 if (libmap_disable || !objgiven ||
1868 (name = lm_find(refobj->path, xname)) == NULL)
1869 name = xname;
1870
1871 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1872 if (name[0] != '/' && !trust) {
1873 _rtld_error("Absolute pathname required "
1874 "for shared object \"%s\"", name);
1875 return (NULL);
1876 }
1877 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1878 __DECONST(char *, name)));
1879 }
1880
1881 dbg(" Searching for \"%s\"", name);
1882 refobj_path = objgiven ? refobj->path : NULL;
1883
1884 /*
1885 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1886 * back to pre-conforming behaviour if user requested so with
1887 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1888 * nodeflib.
1889 */
1890 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1891 pathname = search_library_path(name, ld_library_path,
1892 refobj_path, fdp);
1893 if (pathname != NULL)
1894 return (pathname);
1895 if (refobj != NULL) {
1896 pathname = search_library_path(name, refobj->rpath,
1897 refobj_path, fdp);
1898 if (pathname != NULL)
1899 return (pathname);
1900 }
1901 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1902 if (pathname != NULL)
1903 return (pathname);
1904 pathname = search_library_path(name, gethints(false),
1905 refobj_path, fdp);
1906 if (pathname != NULL)
1907 return (pathname);
1908 pathname = search_library_path(name, ld_standard_library_path,
1909 refobj_path, fdp);
1910 if (pathname != NULL)
1911 return (pathname);
1912 } else {
1913 nodeflib = objgiven ? refobj->z_nodeflib : false;
1914 if (objgiven) {
1915 pathname = search_library_path(name, refobj->rpath,
1916 refobj->path, fdp);
1917 if (pathname != NULL)
1918 return (pathname);
1919 }
1920 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1921 pathname = search_library_path(name, obj_main->rpath,
1922 refobj_path, fdp);
1923 if (pathname != NULL)
1924 return (pathname);
1925 }
1926 pathname = search_library_path(name, ld_library_path,
1927 refobj_path, fdp);
1928 if (pathname != NULL)
1929 return (pathname);
1930 if (objgiven) {
1931 pathname = search_library_path(name, refobj->runpath,
1932 refobj_path, fdp);
1933 if (pathname != NULL)
1934 return (pathname);
1935 }
1936 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1937 if (pathname != NULL)
1938 return (pathname);
1939 pathname = search_library_path(name, gethints(nodeflib),
1940 refobj_path, fdp);
1941 if (pathname != NULL)
1942 return (pathname);
1943 if (objgiven && !nodeflib) {
1944 pathname = search_library_path(name,
1945 ld_standard_library_path, refobj_path, fdp);
1946 if (pathname != NULL)
1947 return (pathname);
1948 }
1949 }
1950
1951 if (objgiven && refobj->path != NULL) {
1952 _rtld_error("Shared object \"%s\" not found, "
1953 "required by \"%s\"", name, basename(refobj->path));
1954 } else {
1955 _rtld_error("Shared object \"%s\" not found", name);
1956 }
1957 return (NULL);
1958 }
1959
1960 /*
1961 * Given a symbol number in a referencing object, find the corresponding
1962 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1963 * no definition was found. Returns a pointer to the Obj_Entry of the
1964 * defining object via the reference parameter DEFOBJ_OUT.
1965 */
1966 const Elf_Sym *
find_symdef(unsigned long symnum,const Obj_Entry * refobj,const Obj_Entry ** defobj_out,int flags,SymCache * cache,RtldLockState * lockstate)1967 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1968 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1969 RtldLockState *lockstate)
1970 {
1971 const Elf_Sym *ref;
1972 const Elf_Sym *def;
1973 const Obj_Entry *defobj;
1974 const Ver_Entry *ve;
1975 SymLook req;
1976 const char *name;
1977 int res;
1978
1979 /*
1980 * If we have already found this symbol, get the information from
1981 * the cache.
1982 */
1983 if (symnum >= refobj->dynsymcount)
1984 return (NULL); /* Bad object */
1985 if (cache != NULL && cache[symnum].sym != NULL) {
1986 *defobj_out = cache[symnum].obj;
1987 return (cache[symnum].sym);
1988 }
1989
1990 ref = refobj->symtab + symnum;
1991 name = refobj->strtab + ref->st_name;
1992 def = NULL;
1993 defobj = NULL;
1994 ve = NULL;
1995
1996 /*
1997 * We don't have to do a full scale lookup if the symbol is local.
1998 * We know it will bind to the instance in this load module; to
1999 * which we already have a pointer (ie ref). By not doing a lookup,
2000 * we not only improve performance, but it also avoids unresolvable
2001 * symbols when local symbols are not in the hash table. This has
2002 * been seen with the ia64 toolchain.
2003 */
2004 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
2005 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
2006 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
2007 symnum);
2008 }
2009 symlook_init(&req, name);
2010 req.flags = flags;
2011 ve = req.ventry = fetch_ventry(refobj, symnum);
2012 req.lockstate = lockstate;
2013 res = symlook_default(&req, refobj);
2014 if (res == 0) {
2015 def = req.sym_out;
2016 defobj = req.defobj_out;
2017 }
2018 } else {
2019 def = ref;
2020 defobj = refobj;
2021 }
2022
2023 /*
2024 * If we found no definition and the reference is weak, treat the
2025 * symbol as having the value zero.
2026 */
2027 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
2028 def = &sym_zero;
2029 defobj = obj_main;
2030 }
2031
2032 if (def != NULL) {
2033 *defobj_out = defobj;
2034 /* Record the information in the cache to avoid subsequent lookups. */
2035 if (cache != NULL) {
2036 cache[symnum].sym = def;
2037 cache[symnum].obj = defobj;
2038 }
2039 } else {
2040 if (refobj != &obj_rtld)
2041 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name,
2042 ve != NULL ? "@" : "", ve != NULL ? ve->name : "");
2043 }
2044 return (def);
2045 }
2046
2047 /* Convert between native byte order and forced little resp. big endian. */
2048 #define COND_SWAP(n) (is_le ? le32toh(n) : be32toh(n))
2049
2050 /*
2051 * Return the search path from the ldconfig hints file, reading it if
2052 * necessary. If nostdlib is true, then the default search paths are
2053 * not added to result.
2054 *
2055 * Returns NULL if there are problems with the hints file,
2056 * or if the search path there is empty.
2057 */
2058 static const char *
gethints(bool nostdlib)2059 gethints(bool nostdlib)
2060 {
2061 static char *filtered_path;
2062 static const char *hints;
2063 static struct elfhints_hdr hdr;
2064 struct fill_search_info_args sargs, hargs;
2065 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
2066 struct dl_serpath *SLPpath, *hintpath;
2067 char *p;
2068 struct stat hint_stat;
2069 unsigned int SLPndx, hintndx, fndx, fcount;
2070 int fd;
2071 size_t flen;
2072 uint32_t dl;
2073 uint32_t magic; /* Magic number */
2074 uint32_t version; /* File version (1) */
2075 uint32_t strtab; /* Offset of string table in file */
2076 uint32_t dirlist; /* Offset of directory list in string table */
2077 uint32_t dirlistlen; /* strlen(dirlist) */
2078 bool is_le; /* Does the hints file use little endian */
2079 bool skip;
2080
2081 /* First call, read the hints file */
2082 if (hints == NULL) {
2083 /* Keep from trying again in case the hints file is bad. */
2084 hints = "";
2085
2086 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) {
2087 dbg("failed to open hints file \"%s\"", ld_elf_hints_path);
2088 return (NULL);
2089 }
2090
2091 /*
2092 * Check of hdr.dirlistlen value against type limit
2093 * intends to pacify static analyzers. Further
2094 * paranoia leads to checks that dirlist is fully
2095 * contained in the file range.
2096 */
2097 if (read(fd, &hdr, sizeof hdr) != sizeof hdr) {
2098 dbg("failed to read %lu bytes from hints file \"%s\"",
2099 (u_long)sizeof hdr, ld_elf_hints_path);
2100 cleanup1:
2101 close(fd);
2102 hdr.dirlistlen = 0;
2103 return (NULL);
2104 }
2105 dbg("host byte-order: %s-endian", le32toh(1) == 1 ? "little" : "big");
2106 dbg("hints file byte-order: %s-endian",
2107 hdr.magic == htole32(ELFHINTS_MAGIC) ? "little" : "big");
2108 is_le = /*htole32(1) == 1 || */ hdr.magic == htole32(ELFHINTS_MAGIC);
2109 magic = COND_SWAP(hdr.magic);
2110 version = COND_SWAP(hdr.version);
2111 strtab = COND_SWAP(hdr.strtab);
2112 dirlist = COND_SWAP(hdr.dirlist);
2113 dirlistlen = COND_SWAP(hdr.dirlistlen);
2114 if (magic != ELFHINTS_MAGIC) {
2115 dbg("invalid magic number %#08x (expected: %#08x)",
2116 magic, ELFHINTS_MAGIC);
2117 goto cleanup1;
2118 }
2119 if (version != 1) {
2120 dbg("hints file version %d (expected: 1)", version);
2121 goto cleanup1;
2122 }
2123 if (dirlistlen > UINT_MAX / 2) {
2124 dbg("directory list is to long: %d > %d",
2125 dirlistlen, UINT_MAX / 2);
2126 goto cleanup1;
2127 }
2128 if (fstat(fd, &hint_stat) == -1) {
2129 dbg("failed to find length of hints file \"%s\"",
2130 ld_elf_hints_path);
2131 goto cleanup1;
2132 }
2133 dl = strtab;
2134 if (dl + dirlist < dl) {
2135 dbg("invalid string table position %d", dl);
2136 goto cleanup1;
2137 }
2138 dl += dirlist;
2139 if (dl + dirlistlen < dl) {
2140 dbg("invalid directory list offset %d", dirlist);
2141 goto cleanup1;
2142 }
2143 dl += dirlistlen;
2144 if (dl > hint_stat.st_size) {
2145 dbg("hints file \"%s\" is truncated (%d vs. %jd bytes)",
2146 ld_elf_hints_path, dl, (uintmax_t)hint_stat.st_size);
2147 goto cleanup1;
2148 }
2149 p = xmalloc(dirlistlen + 1);
2150 if (pread(fd, p, dirlistlen + 1,
2151 strtab + dirlist) != (ssize_t)dirlistlen + 1 ||
2152 p[dirlistlen] != '\0') {
2153 free(p);
2154 dbg("failed to read %d bytes starting at %d from hints file \"%s\"",
2155 dirlistlen + 1, strtab + dirlist, ld_elf_hints_path);
2156 goto cleanup1;
2157 }
2158 hints = p;
2159 close(fd);
2160 }
2161
2162 /*
2163 * If caller agreed to receive list which includes the default
2164 * paths, we are done. Otherwise, if we still did not
2165 * calculated filtered result, do it now.
2166 */
2167 if (!nostdlib)
2168 return (hints[0] != '\0' ? hints : NULL);
2169 if (filtered_path != NULL)
2170 goto filt_ret;
2171
2172 /*
2173 * Obtain the list of all configured search paths, and the
2174 * list of the default paths.
2175 *
2176 * First estimate the size of the results.
2177 */
2178 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2179 smeta.dls_cnt = 0;
2180 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2181 hmeta.dls_cnt = 0;
2182
2183 sargs.request = RTLD_DI_SERINFOSIZE;
2184 sargs.serinfo = &smeta;
2185 hargs.request = RTLD_DI_SERINFOSIZE;
2186 hargs.serinfo = &hmeta;
2187
2188 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
2189 &sargs);
2190 path_enumerate(hints, fill_search_info, NULL, &hargs);
2191
2192 SLPinfo = xmalloc(smeta.dls_size);
2193 hintinfo = xmalloc(hmeta.dls_size);
2194
2195 /*
2196 * Next fetch both sets of paths.
2197 */
2198 sargs.request = RTLD_DI_SERINFO;
2199 sargs.serinfo = SLPinfo;
2200 sargs.serpath = &SLPinfo->dls_serpath[0];
2201 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
2202
2203 hargs.request = RTLD_DI_SERINFO;
2204 hargs.serinfo = hintinfo;
2205 hargs.serpath = &hintinfo->dls_serpath[0];
2206 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
2207
2208 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
2209 &sargs);
2210 path_enumerate(hints, fill_search_info, NULL, &hargs);
2211
2212 /*
2213 * Now calculate the difference between two sets, by excluding
2214 * standard paths from the full set.
2215 */
2216 fndx = 0;
2217 fcount = 0;
2218 filtered_path = xmalloc(dirlistlen + 1);
2219 hintpath = &hintinfo->dls_serpath[0];
2220 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
2221 skip = false;
2222 SLPpath = &SLPinfo->dls_serpath[0];
2223 /*
2224 * Check each standard path against current.
2225 */
2226 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
2227 /* matched, skip the path */
2228 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
2229 skip = true;
2230 break;
2231 }
2232 }
2233 if (skip)
2234 continue;
2235 /*
2236 * Not matched against any standard path, add the path
2237 * to result. Separate consequtive paths with ':'.
2238 */
2239 if (fcount > 0) {
2240 filtered_path[fndx] = ':';
2241 fndx++;
2242 }
2243 fcount++;
2244 flen = strlen(hintpath->dls_name);
2245 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
2246 fndx += flen;
2247 }
2248 filtered_path[fndx] = '\0';
2249
2250 free(SLPinfo);
2251 free(hintinfo);
2252
2253 filt_ret:
2254 return (filtered_path[0] != '\0' ? filtered_path : NULL);
2255 }
2256
2257 static void
init_dag(Obj_Entry * root)2258 init_dag(Obj_Entry *root)
2259 {
2260 const Needed_Entry *needed;
2261 const Objlist_Entry *elm;
2262 DoneList donelist;
2263
2264 if (root->dag_inited)
2265 return;
2266 donelist_init(&donelist);
2267
2268 /* Root object belongs to own DAG. */
2269 objlist_push_tail(&root->dldags, root);
2270 objlist_push_tail(&root->dagmembers, root);
2271 donelist_check(&donelist, root);
2272
2273 /*
2274 * Add dependencies of root object to DAG in breadth order
2275 * by exploiting the fact that each new object get added
2276 * to the tail of the dagmembers list.
2277 */
2278 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2279 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
2280 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
2281 continue;
2282 objlist_push_tail(&needed->obj->dldags, root);
2283 objlist_push_tail(&root->dagmembers, needed->obj);
2284 }
2285 }
2286 root->dag_inited = true;
2287 }
2288
2289 static void
init_marker(Obj_Entry * marker)2290 init_marker(Obj_Entry *marker)
2291 {
2292
2293 bzero(marker, sizeof(*marker));
2294 marker->marker = true;
2295 }
2296
2297 Obj_Entry *
globallist_curr(const Obj_Entry * obj)2298 globallist_curr(const Obj_Entry *obj)
2299 {
2300
2301 for (;;) {
2302 if (obj == NULL)
2303 return (NULL);
2304 if (!obj->marker)
2305 return (__DECONST(Obj_Entry *, obj));
2306 obj = TAILQ_PREV(obj, obj_entry_q, next);
2307 }
2308 }
2309
2310 Obj_Entry *
globallist_next(const Obj_Entry * obj)2311 globallist_next(const Obj_Entry *obj)
2312 {
2313
2314 for (;;) {
2315 obj = TAILQ_NEXT(obj, next);
2316 if (obj == NULL)
2317 return (NULL);
2318 if (!obj->marker)
2319 return (__DECONST(Obj_Entry *, obj));
2320 }
2321 }
2322
2323 /* Prevent the object from being unmapped while the bind lock is dropped. */
2324 static void
hold_object(Obj_Entry * obj)2325 hold_object(Obj_Entry *obj)
2326 {
2327
2328 obj->holdcount++;
2329 }
2330
2331 static void
unhold_object(Obj_Entry * obj)2332 unhold_object(Obj_Entry *obj)
2333 {
2334
2335 assert(obj->holdcount > 0);
2336 if (--obj->holdcount == 0 && obj->unholdfree)
2337 release_object(obj);
2338 }
2339
2340 static void
process_z(Obj_Entry * root)2341 process_z(Obj_Entry *root)
2342 {
2343 const Objlist_Entry *elm;
2344 Obj_Entry *obj;
2345
2346 /*
2347 * Walk over object DAG and process every dependent object
2348 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2349 * to grow their own DAG.
2350 *
2351 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2352 * symlook_global() to work.
2353 *
2354 * For DF_1_NODELETE, the DAG should have its reference upped.
2355 */
2356 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2357 obj = elm->obj;
2358 if (obj == NULL)
2359 continue;
2360 if (obj->z_nodelete && !obj->ref_nodel) {
2361 dbg("obj %s -z nodelete", obj->path);
2362 init_dag(obj);
2363 ref_dag(obj);
2364 obj->ref_nodel = true;
2365 }
2366 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2367 dbg("obj %s -z global", obj->path);
2368 objlist_push_tail(&list_global, obj);
2369 init_dag(obj);
2370 }
2371 }
2372 }
2373
2374 static void
parse_rtld_phdr(Obj_Entry * obj)2375 parse_rtld_phdr(Obj_Entry *obj)
2376 {
2377 const Elf_Phdr *ph;
2378 Elf_Addr note_start, note_end;
2379
2380 obj->stack_flags = PF_X | PF_R | PF_W;
2381 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr +
2382 obj->phsize; ph++) {
2383 switch (ph->p_type) {
2384 case PT_GNU_STACK:
2385 obj->stack_flags = ph->p_flags;
2386 break;
2387 case PT_GNU_RELRO:
2388 obj->relro_page = obj->relocbase +
2389 rtld_trunc_page(ph->p_vaddr);
2390 obj->relro_size = rtld_round_page(ph->p_memsz);
2391 break;
2392 case PT_NOTE:
2393 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
2394 note_end = note_start + ph->p_filesz;
2395 digest_notes(obj, note_start, note_end);
2396 break;
2397 }
2398 }
2399 }
2400
2401 /*
2402 * Initialize the dynamic linker. The argument is the address at which
2403 * the dynamic linker has been mapped into memory. The primary task of
2404 * this function is to relocate the dynamic linker.
2405 */
2406 static void
init_rtld(caddr_t mapbase,Elf_Auxinfo ** aux_info)2407 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2408 {
2409 Obj_Entry objtmp; /* Temporary rtld object */
2410 const Elf_Ehdr *ehdr;
2411 const Elf_Dyn *dyn_rpath;
2412 const Elf_Dyn *dyn_soname;
2413 const Elf_Dyn *dyn_runpath;
2414
2415 #ifdef RTLD_INIT_PAGESIZES_EARLY
2416 /* The page size is required by the dynamic memory allocator. */
2417 init_pagesizes(aux_info);
2418 #endif
2419
2420 /*
2421 * Conjure up an Obj_Entry structure for the dynamic linker.
2422 *
2423 * The "path" member can't be initialized yet because string constants
2424 * cannot yet be accessed. Below we will set it correctly.
2425 */
2426 memset(&objtmp, 0, sizeof(objtmp));
2427 objtmp.path = NULL;
2428 objtmp.rtld = true;
2429 objtmp.mapbase = mapbase;
2430 #ifdef PIC
2431 objtmp.relocbase = mapbase;
2432 #endif
2433
2434 objtmp.dynamic = rtld_dynamic(&objtmp);
2435 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2436 assert(objtmp.needed == NULL);
2437 assert(!objtmp.textrel);
2438 /*
2439 * Temporarily put the dynamic linker entry into the object list, so
2440 * that symbols can be found.
2441 */
2442 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2443
2444 ehdr = (Elf_Ehdr *)mapbase;
2445 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2446 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]);
2447
2448 /* Initialize the object list. */
2449 TAILQ_INIT(&obj_list);
2450
2451 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2452 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2453
2454 #ifndef RTLD_INIT_PAGESIZES_EARLY
2455 /* The page size is required by the dynamic memory allocator. */
2456 init_pagesizes(aux_info);
2457 #endif
2458
2459 if (aux_info[AT_OSRELDATE] != NULL)
2460 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2461
2462 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2463
2464 /* Replace the path with a dynamically allocated copy. */
2465 obj_rtld.path = xstrdup(ld_path_rtld);
2466
2467 parse_rtld_phdr(&obj_rtld);
2468 if (obj_enforce_relro(&obj_rtld) == -1)
2469 rtld_die();
2470
2471 r_debug.r_version = R_DEBUG_VERSION;
2472 r_debug.r_brk = r_debug_state;
2473 r_debug.r_state = RT_CONSISTENT;
2474 r_debug.r_ldbase = obj_rtld.relocbase;
2475 }
2476
2477 /*
2478 * Retrieve the array of supported page sizes. The kernel provides the page
2479 * sizes in increasing order.
2480 */
2481 static void
init_pagesizes(Elf_Auxinfo ** aux_info)2482 init_pagesizes(Elf_Auxinfo **aux_info)
2483 {
2484 static size_t psa[MAXPAGESIZES];
2485 int mib[2];
2486 size_t len, size;
2487
2488 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
2489 NULL) {
2490 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2491 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2492 } else {
2493 len = 2;
2494 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2495 size = sizeof(psa);
2496 else {
2497 /* As a fallback, retrieve the base page size. */
2498 size = sizeof(psa[0]);
2499 if (aux_info[AT_PAGESZ] != NULL) {
2500 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2501 goto psa_filled;
2502 } else {
2503 mib[0] = CTL_HW;
2504 mib[1] = HW_PAGESIZE;
2505 len = 2;
2506 }
2507 }
2508 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2509 _rtld_error("sysctl for hw.pagesize(s) failed");
2510 rtld_die();
2511 }
2512 psa_filled:
2513 pagesizes = psa;
2514 }
2515 npagesizes = size / sizeof(pagesizes[0]);
2516 /* Discard any invalid entries at the end of the array. */
2517 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2518 npagesizes--;
2519
2520 page_size = pagesizes[0];
2521 }
2522
2523 /*
2524 * Add the init functions from a needed object list (and its recursive
2525 * needed objects) to "list". This is not used directly; it is a helper
2526 * function for initlist_add_objects(). The write lock must be held
2527 * when this function is called.
2528 */
2529 static void
initlist_add_neededs(Needed_Entry * needed,Objlist * list)2530 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
2531 {
2532 /* Recursively process the successor needed objects. */
2533 if (needed->next != NULL)
2534 initlist_add_neededs(needed->next, list);
2535
2536 /* Process the current needed object. */
2537 if (needed->obj != NULL)
2538 initlist_add_objects(needed->obj, needed->obj, list);
2539 }
2540
2541 /*
2542 * Scan all of the DAGs rooted in the range of objects from "obj" to
2543 * "tail" and add their init functions to "list". This recurses over
2544 * the DAGs and ensure the proper init ordering such that each object's
2545 * needed libraries are initialized before the object itself. At the
2546 * same time, this function adds the objects to the global finalization
2547 * list "list_fini" in the opposite order. The write lock must be
2548 * held when this function is called.
2549 */
2550 static void
initlist_add_objects(Obj_Entry * obj,Obj_Entry * tail,Objlist * list)2551 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2552 {
2553 Obj_Entry *nobj;
2554
2555 if (obj->init_scanned || obj->init_done)
2556 return;
2557 obj->init_scanned = true;
2558
2559 /* Recursively process the successor objects. */
2560 nobj = globallist_next(obj);
2561 if (nobj != NULL && obj != tail)
2562 initlist_add_objects(nobj, tail, list);
2563
2564 /* Recursively process the needed objects. */
2565 if (obj->needed != NULL)
2566 initlist_add_neededs(obj->needed, list);
2567 if (obj->needed_filtees != NULL)
2568 initlist_add_neededs(obj->needed_filtees, list);
2569 if (obj->needed_aux_filtees != NULL)
2570 initlist_add_neededs(obj->needed_aux_filtees, list);
2571
2572 /* Add the object to the init list. */
2573 objlist_push_tail(list, obj);
2574
2575 /* Add the object to the global fini list in the reverse order. */
2576 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2577 && !obj->on_fini_list) {
2578 objlist_push_head(&list_fini, obj);
2579 obj->on_fini_list = true;
2580 }
2581 }
2582
2583 static void
free_needed_filtees(Needed_Entry * n,RtldLockState * lockstate)2584 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2585 {
2586 Needed_Entry *needed, *needed1;
2587
2588 for (needed = n; needed != NULL; needed = needed->next) {
2589 if (needed->obj != NULL) {
2590 dlclose_locked(needed->obj, lockstate);
2591 needed->obj = NULL;
2592 }
2593 }
2594 for (needed = n; needed != NULL; needed = needed1) {
2595 needed1 = needed->next;
2596 free(needed);
2597 }
2598 }
2599
2600 static void
unload_filtees(Obj_Entry * obj,RtldLockState * lockstate)2601 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2602 {
2603
2604 free_needed_filtees(obj->needed_filtees, lockstate);
2605 obj->needed_filtees = NULL;
2606 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2607 obj->needed_aux_filtees = NULL;
2608 obj->filtees_loaded = false;
2609 }
2610
2611 static void
load_filtee1(Obj_Entry * obj,Needed_Entry * needed,int flags,RtldLockState * lockstate)2612 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2613 RtldLockState *lockstate)
2614 {
2615
2616 for (; needed != NULL; needed = needed->next) {
2617 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2618 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2619 RTLD_LOCAL, lockstate);
2620 }
2621 }
2622
2623 static void
load_filtees(Obj_Entry * obj,int flags,RtldLockState * lockstate)2624 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2625 {
2626 if (obj->filtees_loaded || obj->filtees_loading)
2627 return;
2628 lock_restart_for_upgrade(lockstate);
2629 obj->filtees_loading = true;
2630 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2631 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2632 obj->filtees_loaded = true;
2633 obj->filtees_loading = false;
2634 }
2635
2636 static int
process_needed(Obj_Entry * obj,Needed_Entry * needed,int flags)2637 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2638 {
2639 Obj_Entry *obj1;
2640
2641 for (; needed != NULL; needed = needed->next) {
2642 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2643 flags & ~RTLD_LO_NOLOAD);
2644 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2645 return (-1);
2646 }
2647 return (0);
2648 }
2649
2650 /*
2651 * Given a shared object, traverse its list of needed objects, and load
2652 * each of them. Returns 0 on success. Generates an error message and
2653 * returns -1 on failure.
2654 */
2655 static int
load_needed_objects(Obj_Entry * first,int flags)2656 load_needed_objects(Obj_Entry *first, int flags)
2657 {
2658 Obj_Entry *obj;
2659
2660 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2661 if (obj->marker)
2662 continue;
2663 if (process_needed(obj, obj->needed, flags) == -1)
2664 return (-1);
2665 }
2666 return (0);
2667 }
2668
2669 static int
load_preload_objects(const char * penv,bool isfd)2670 load_preload_objects(const char *penv, bool isfd)
2671 {
2672 Obj_Entry *obj;
2673 const char *name;
2674 size_t len;
2675 char savech, *p, *psave;
2676 int fd;
2677 static const char delim[] = " \t:;";
2678
2679 if (penv == NULL)
2680 return (0);
2681
2682 p = psave = xstrdup(penv);
2683 p += strspn(p, delim);
2684 while (*p != '\0') {
2685 len = strcspn(p, delim);
2686
2687 savech = p[len];
2688 p[len] = '\0';
2689 if (isfd) {
2690 name = NULL;
2691 fd = parse_integer(p);
2692 if (fd == -1) {
2693 free(psave);
2694 return (-1);
2695 }
2696 } else {
2697 name = p;
2698 fd = -1;
2699 }
2700
2701 obj = load_object(name, fd, NULL, 0);
2702 if (obj == NULL) {
2703 free(psave);
2704 return (-1); /* XXX - cleanup */
2705 }
2706 obj->z_interpose = true;
2707 p[len] = savech;
2708 p += len;
2709 p += strspn(p, delim);
2710 }
2711 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2712
2713 free(psave);
2714 return (0);
2715 }
2716
2717 static const char *
printable_path(const char * path)2718 printable_path(const char *path)
2719 {
2720
2721 return (path == NULL ? "<unknown>" : path);
2722 }
2723
2724 /*
2725 * Load a shared object into memory, if it is not already loaded. The
2726 * object may be specified by name or by user-supplied file descriptor
2727 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2728 * duplicate is.
2729 *
2730 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2731 * on failure.
2732 */
2733 static Obj_Entry *
load_object(const char * name,int fd_u,const Obj_Entry * refobj,int flags)2734 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2735 {
2736 Obj_Entry *obj;
2737 int fd;
2738 struct stat sb;
2739 char *path;
2740
2741 fd = -1;
2742 if (name != NULL) {
2743 TAILQ_FOREACH(obj, &obj_list, next) {
2744 if (obj->marker || obj->doomed)
2745 continue;
2746 if (object_match_name(obj, name))
2747 return (obj);
2748 }
2749
2750 path = find_library(name, refobj, &fd);
2751 if (path == NULL)
2752 return (NULL);
2753 } else
2754 path = NULL;
2755
2756 if (fd >= 0) {
2757 /*
2758 * search_library_pathfds() opens a fresh file descriptor for the
2759 * library, so there is no need to dup().
2760 */
2761 } else if (fd_u == -1) {
2762 /*
2763 * If we didn't find a match by pathname, or the name is not
2764 * supplied, open the file and check again by device and inode.
2765 * This avoids false mismatches caused by multiple links or ".."
2766 * in pathnames.
2767 *
2768 * To avoid a race, we open the file and use fstat() rather than
2769 * using stat().
2770 */
2771 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2772 _rtld_error("Cannot open \"%s\"", path);
2773 free(path);
2774 return (NULL);
2775 }
2776 } else {
2777 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2778 if (fd == -1) {
2779 _rtld_error("Cannot dup fd");
2780 free(path);
2781 return (NULL);
2782 }
2783 }
2784 if (fstat(fd, &sb) == -1) {
2785 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2786 close(fd);
2787 free(path);
2788 return (NULL);
2789 }
2790 TAILQ_FOREACH(obj, &obj_list, next) {
2791 if (obj->marker || obj->doomed)
2792 continue;
2793 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2794 break;
2795 }
2796 if (obj != NULL) {
2797 if (name != NULL)
2798 object_add_name(obj, name);
2799 free(path);
2800 close(fd);
2801 return (obj);
2802 }
2803 if (flags & RTLD_LO_NOLOAD) {
2804 free(path);
2805 close(fd);
2806 return (NULL);
2807 }
2808
2809 /* First use of this object, so we must map it in */
2810 obj = do_load_object(fd, name, path, &sb, flags);
2811 if (obj == NULL)
2812 free(path);
2813 close(fd);
2814
2815 return (obj);
2816 }
2817
2818 static Obj_Entry *
do_load_object(int fd,const char * name,char * path,struct stat * sbp,int flags)2819 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2820 int flags)
2821 {
2822 Obj_Entry *obj;
2823 struct statfs fs;
2824
2825 /*
2826 * First, make sure that environment variables haven't been
2827 * used to circumvent the noexec flag on a filesystem.
2828 * We ignore fstatfs(2) failures, since fd might reference
2829 * not a file, e.g. shmfd.
2830 */
2831 if (dangerous_ld_env && fstatfs(fd, &fs) == 0 &&
2832 (fs.f_flags & MNT_NOEXEC) != 0) {
2833 _rtld_error("Cannot execute objects on %s", fs.f_mntonname);
2834 return (NULL);
2835 }
2836
2837 dbg("loading \"%s\"", printable_path(path));
2838 obj = map_object(fd, printable_path(path), sbp);
2839 if (obj == NULL)
2840 return (NULL);
2841
2842 /*
2843 * If DT_SONAME is present in the object, digest_dynamic2 already
2844 * added it to the object names.
2845 */
2846 if (name != NULL)
2847 object_add_name(obj, name);
2848 obj->path = path;
2849 if (!digest_dynamic(obj, 0))
2850 goto errp;
2851 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2852 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2853 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) {
2854 dbg("refusing to load PIE executable \"%s\"", obj->path);
2855 _rtld_error("Cannot load PIE binary %s as DSO", obj->path);
2856 goto errp;
2857 }
2858 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2859 RTLD_LO_DLOPEN) {
2860 dbg("refusing to load non-loadable \"%s\"", obj->path);
2861 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2862 goto errp;
2863 }
2864
2865 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2866 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2867 obj_count++;
2868 obj_loads++;
2869 linkmap_add(obj); /* for GDB & dlinfo() */
2870 max_stack_flags |= obj->stack_flags;
2871
2872 dbg(" %p .. %p: %s", obj->mapbase,
2873 obj->mapbase + obj->mapsize - 1, obj->path);
2874 if (obj->textrel)
2875 dbg(" WARNING: %s has impure text", obj->path);
2876 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2877 obj->path);
2878
2879 return (obj);
2880
2881 errp:
2882 munmap(obj->mapbase, obj->mapsize);
2883 obj_free(obj);
2884 return (NULL);
2885 }
2886
2887 static int
load_kpreload(const void * addr)2888 load_kpreload(const void *addr)
2889 {
2890 Obj_Entry *obj;
2891 const Elf_Ehdr *ehdr;
2892 const Elf_Phdr *phdr, *phlimit, *phdyn, *seg0, *segn;
2893 static const char kname[] = "[vdso]";
2894
2895 ehdr = addr;
2896 if (!check_elf_headers(ehdr, "kpreload"))
2897 return (-1);
2898 obj = obj_new();
2899 phdr = (const Elf_Phdr *)((const char *)addr + ehdr->e_phoff);
2900 obj->phdr = phdr;
2901 obj->phsize = ehdr->e_phnum * sizeof(*phdr);
2902 phlimit = phdr + ehdr->e_phnum;
2903 seg0 = segn = NULL;
2904
2905 for (; phdr < phlimit; phdr++) {
2906 switch (phdr->p_type) {
2907 case PT_DYNAMIC:
2908 phdyn = phdr;
2909 break;
2910 case PT_GNU_STACK:
2911 /* Absense of PT_GNU_STACK implies stack_flags == 0. */
2912 obj->stack_flags = phdr->p_flags;
2913 break;
2914 case PT_LOAD:
2915 if (seg0 == NULL || seg0->p_vaddr > phdr->p_vaddr)
2916 seg0 = phdr;
2917 if (segn == NULL || segn->p_vaddr + segn->p_memsz <
2918 phdr->p_vaddr + phdr->p_memsz)
2919 segn = phdr;
2920 break;
2921 }
2922 }
2923
2924 obj->mapbase = __DECONST(caddr_t, addr);
2925 obj->mapsize = segn->p_vaddr + segn->p_memsz - (Elf_Addr)addr;
2926 obj->vaddrbase = 0;
2927 obj->relocbase = obj->mapbase;
2928
2929 object_add_name(obj, kname);
2930 obj->path = xstrdup(kname);
2931 obj->dynamic = (const Elf_Dyn *)(obj->relocbase + phdyn->p_vaddr);
2932
2933 if (!digest_dynamic(obj, 0)) {
2934 obj_free(obj);
2935 return (-1);
2936 }
2937
2938 /*
2939 * We assume that kernel-preloaded object does not need
2940 * relocation. It is currently written into read-only page,
2941 * handling relocations would mean we need to allocate at
2942 * least one additional page per AS.
2943 */
2944 dbg("%s mapbase %p phdrs %p PT_LOAD phdr %p vaddr %p dynamic %p",
2945 obj->path, obj->mapbase, obj->phdr, seg0,
2946 obj->relocbase + seg0->p_vaddr, obj->dynamic);
2947
2948 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2949 obj_count++;
2950 obj_loads++;
2951 linkmap_add(obj); /* for GDB & dlinfo() */
2952 max_stack_flags |= obj->stack_flags;
2953
2954 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, 0, 0, obj->path);
2955 return (0);
2956 }
2957
2958 Obj_Entry *
obj_from_addr(const void * addr)2959 obj_from_addr(const void *addr)
2960 {
2961 Obj_Entry *obj;
2962
2963 TAILQ_FOREACH(obj, &obj_list, next) {
2964 if (obj->marker)
2965 continue;
2966 if (addr < (void *) obj->mapbase)
2967 continue;
2968 if (addr < (void *)(obj->mapbase + obj->mapsize))
2969 return obj;
2970 }
2971 return (NULL);
2972 }
2973
2974 static void
preinit_main(void)2975 preinit_main(void)
2976 {
2977 Elf_Addr *preinit_addr;
2978 int index;
2979
2980 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2981 if (preinit_addr == NULL)
2982 return;
2983
2984 for (index = 0; index < obj_main->preinit_array_num; index++) {
2985 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2986 dbg("calling preinit function for %s at %p", obj_main->path,
2987 (void *)preinit_addr[index]);
2988 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2989 0, 0, obj_main->path);
2990 call_init_pointer(obj_main, preinit_addr[index]);
2991 }
2992 }
2993 }
2994
2995 /*
2996 * Call the finalization functions for each of the objects in "list"
2997 * belonging to the DAG of "root" and referenced once. If NULL "root"
2998 * is specified, every finalization function will be called regardless
2999 * of the reference count and the list elements won't be freed. All of
3000 * the objects are expected to have non-NULL fini functions.
3001 */
3002 static void
objlist_call_fini(Objlist * list,Obj_Entry * root,RtldLockState * lockstate)3003 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
3004 {
3005 Objlist_Entry *elm;
3006 struct dlerror_save *saved_msg;
3007 Elf_Addr *fini_addr;
3008 int index;
3009
3010 assert(root == NULL || root->refcount == 1);
3011
3012 if (root != NULL)
3013 root->doomed = true;
3014
3015 /*
3016 * Preserve the current error message since a fini function might
3017 * call into the dynamic linker and overwrite it.
3018 */
3019 saved_msg = errmsg_save();
3020 do {
3021 STAILQ_FOREACH(elm, list, link) {
3022 if (root != NULL && (elm->obj->refcount != 1 ||
3023 objlist_find(&root->dagmembers, elm->obj) == NULL))
3024 continue;
3025 /* Remove object from fini list to prevent recursive invocation. */
3026 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
3027 /* Ensure that new references cannot be acquired. */
3028 elm->obj->doomed = true;
3029
3030 hold_object(elm->obj);
3031 lock_release(rtld_bind_lock, lockstate);
3032 /*
3033 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
3034 * When this happens, DT_FINI_ARRAY is processed first.
3035 */
3036 fini_addr = (Elf_Addr *)elm->obj->fini_array;
3037 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
3038 for (index = elm->obj->fini_array_num - 1; index >= 0;
3039 index--) {
3040 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
3041 dbg("calling fini function for %s at %p",
3042 elm->obj->path, (void *)fini_addr[index]);
3043 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
3044 (void *)fini_addr[index], 0, 0, elm->obj->path);
3045 call_initfini_pointer(elm->obj, fini_addr[index]);
3046 }
3047 }
3048 }
3049 if (elm->obj->fini != (Elf_Addr)NULL) {
3050 dbg("calling fini function for %s at %p", elm->obj->path,
3051 (void *)elm->obj->fini);
3052 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
3053 0, 0, elm->obj->path);
3054 call_initfini_pointer(elm->obj, elm->obj->fini);
3055 }
3056 wlock_acquire(rtld_bind_lock, lockstate);
3057 unhold_object(elm->obj);
3058 /* No need to free anything if process is going down. */
3059 if (root != NULL)
3060 free(elm);
3061 /*
3062 * We must restart the list traversal after every fini call
3063 * because a dlclose() call from the fini function or from
3064 * another thread might have modified the reference counts.
3065 */
3066 break;
3067 }
3068 } while (elm != NULL);
3069 errmsg_restore(saved_msg);
3070 }
3071
3072 /*
3073 * Call the initialization functions for each of the objects in
3074 * "list". All of the objects are expected to have non-NULL init
3075 * functions.
3076 */
3077 static void
objlist_call_init(Objlist * list,RtldLockState * lockstate)3078 objlist_call_init(Objlist *list, RtldLockState *lockstate)
3079 {
3080 Objlist_Entry *elm;
3081 Obj_Entry *obj;
3082 struct dlerror_save *saved_msg;
3083 Elf_Addr *init_addr;
3084 void (*reg)(void (*)(void));
3085 int index;
3086
3087 /*
3088 * Clean init_scanned flag so that objects can be rechecked and
3089 * possibly initialized earlier if any of vectors called below
3090 * cause the change by using dlopen.
3091 */
3092 TAILQ_FOREACH(obj, &obj_list, next) {
3093 if (obj->marker)
3094 continue;
3095 obj->init_scanned = false;
3096 }
3097
3098 /*
3099 * Preserve the current error message since an init function might
3100 * call into the dynamic linker and overwrite it.
3101 */
3102 saved_msg = errmsg_save();
3103 STAILQ_FOREACH(elm, list, link) {
3104 if (elm->obj->init_done) /* Initialized early. */
3105 continue;
3106 /*
3107 * Race: other thread might try to use this object before current
3108 * one completes the initialization. Not much can be done here
3109 * without better locking.
3110 */
3111 elm->obj->init_done = true;
3112 hold_object(elm->obj);
3113 reg = NULL;
3114 if (elm->obj == obj_main && obj_main->crt_no_init) {
3115 reg = (void (*)(void (*)(void)))get_program_var_addr(
3116 "__libc_atexit", lockstate);
3117 }
3118 lock_release(rtld_bind_lock, lockstate);
3119 if (reg != NULL) {
3120 reg(rtld_exit);
3121 rtld_exit_ptr = rtld_nop_exit;
3122 }
3123
3124 /*
3125 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
3126 * When this happens, DT_INIT is processed first.
3127 */
3128 if (elm->obj->init != (Elf_Addr)NULL) {
3129 dbg("calling init function for %s at %p", elm->obj->path,
3130 (void *)elm->obj->init);
3131 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
3132 0, 0, elm->obj->path);
3133 call_init_pointer(elm->obj, elm->obj->init);
3134 }
3135 init_addr = (Elf_Addr *)elm->obj->init_array;
3136 if (init_addr != NULL) {
3137 for (index = 0; index < elm->obj->init_array_num; index++) {
3138 if (init_addr[index] != 0 && init_addr[index] != 1) {
3139 dbg("calling init function for %s at %p", elm->obj->path,
3140 (void *)init_addr[index]);
3141 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
3142 (void *)init_addr[index], 0, 0, elm->obj->path);
3143 call_init_pointer(elm->obj, init_addr[index]);
3144 }
3145 }
3146 }
3147 wlock_acquire(rtld_bind_lock, lockstate);
3148 unhold_object(elm->obj);
3149 }
3150 errmsg_restore(saved_msg);
3151 }
3152
3153 static void
objlist_clear(Objlist * list)3154 objlist_clear(Objlist *list)
3155 {
3156 Objlist_Entry *elm;
3157
3158 while (!STAILQ_EMPTY(list)) {
3159 elm = STAILQ_FIRST(list);
3160 STAILQ_REMOVE_HEAD(list, link);
3161 free(elm);
3162 }
3163 }
3164
3165 static Objlist_Entry *
objlist_find(Objlist * list,const Obj_Entry * obj)3166 objlist_find(Objlist *list, const Obj_Entry *obj)
3167 {
3168 Objlist_Entry *elm;
3169
3170 STAILQ_FOREACH(elm, list, link)
3171 if (elm->obj == obj)
3172 return elm;
3173 return (NULL);
3174 }
3175
3176 static void
objlist_init(Objlist * list)3177 objlist_init(Objlist *list)
3178 {
3179 STAILQ_INIT(list);
3180 }
3181
3182 static void
objlist_push_head(Objlist * list,Obj_Entry * obj)3183 objlist_push_head(Objlist *list, Obj_Entry *obj)
3184 {
3185 Objlist_Entry *elm;
3186
3187 elm = NEW(Objlist_Entry);
3188 elm->obj = obj;
3189 STAILQ_INSERT_HEAD(list, elm, link);
3190 }
3191
3192 static void
objlist_push_tail(Objlist * list,Obj_Entry * obj)3193 objlist_push_tail(Objlist *list, Obj_Entry *obj)
3194 {
3195 Objlist_Entry *elm;
3196
3197 elm = NEW(Objlist_Entry);
3198 elm->obj = obj;
3199 STAILQ_INSERT_TAIL(list, elm, link);
3200 }
3201
3202 static void
objlist_put_after(Objlist * list,Obj_Entry * listobj,Obj_Entry * obj)3203 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
3204 {
3205 Objlist_Entry *elm, *listelm;
3206
3207 STAILQ_FOREACH(listelm, list, link) {
3208 if (listelm->obj == listobj)
3209 break;
3210 }
3211 elm = NEW(Objlist_Entry);
3212 elm->obj = obj;
3213 if (listelm != NULL)
3214 STAILQ_INSERT_AFTER(list, listelm, elm, link);
3215 else
3216 STAILQ_INSERT_TAIL(list, elm, link);
3217 }
3218
3219 static void
objlist_remove(Objlist * list,Obj_Entry * obj)3220 objlist_remove(Objlist *list, Obj_Entry *obj)
3221 {
3222 Objlist_Entry *elm;
3223
3224 if ((elm = objlist_find(list, obj)) != NULL) {
3225 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
3226 free(elm);
3227 }
3228 }
3229
3230 /*
3231 * Relocate dag rooted in the specified object.
3232 * Returns 0 on success, or -1 on failure.
3233 */
3234
3235 static int
relocate_object_dag(Obj_Entry * root,bool bind_now,Obj_Entry * rtldobj,int flags,RtldLockState * lockstate)3236 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
3237 int flags, RtldLockState *lockstate)
3238 {
3239 Objlist_Entry *elm;
3240 int error;
3241
3242 error = 0;
3243 STAILQ_FOREACH(elm, &root->dagmembers, link) {
3244 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
3245 lockstate);
3246 if (error == -1)
3247 break;
3248 }
3249 return (error);
3250 }
3251
3252 /*
3253 * Prepare for, or clean after, relocating an object marked with
3254 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
3255 * segments are remapped read-write. After relocations are done, the
3256 * segment's permissions are returned back to the modes specified in
3257 * the phdrs. If any relocation happened, or always for wired
3258 * program, COW is triggered.
3259 */
3260 static int
reloc_textrel_prot(Obj_Entry * obj,bool before)3261 reloc_textrel_prot(Obj_Entry *obj, bool before)
3262 {
3263 const Elf_Phdr *ph;
3264 void *base;
3265 size_t l, sz;
3266 int prot;
3267
3268 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
3269 l--, ph++) {
3270 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
3271 continue;
3272 base = obj->relocbase + rtld_trunc_page(ph->p_vaddr);
3273 sz = rtld_round_page(ph->p_vaddr + ph->p_filesz) -
3274 rtld_trunc_page(ph->p_vaddr);
3275 prot = before ? (PROT_READ | PROT_WRITE) :
3276 convert_prot(ph->p_flags);
3277 if (mprotect(base, sz, prot) == -1) {
3278 _rtld_error("%s: Cannot write-%sable text segment: %s",
3279 obj->path, before ? "en" : "dis",
3280 rtld_strerror(errno));
3281 return (-1);
3282 }
3283 }
3284 return (0);
3285 }
3286
3287 /* Process RELR relative relocations. */
3288 static void
reloc_relr(Obj_Entry * obj)3289 reloc_relr(Obj_Entry *obj)
3290 {
3291 const Elf_Relr *relr, *relrlim;
3292 Elf_Addr *where;
3293
3294 relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize);
3295 for (relr = obj->relr; relr < relrlim; relr++) {
3296 Elf_Relr entry = *relr;
3297
3298 if ((entry & 1) == 0) {
3299 where = (Elf_Addr *)(obj->relocbase + entry);
3300 *where++ += (Elf_Addr)obj->relocbase;
3301 } else {
3302 for (long i = 0; (entry >>= 1) != 0; i++)
3303 if ((entry & 1) != 0)
3304 where[i] += (Elf_Addr)obj->relocbase;
3305 where += CHAR_BIT * sizeof(Elf_Relr) - 1;
3306 }
3307 }
3308 }
3309
3310 /*
3311 * Relocate single object.
3312 * Returns 0 on success, or -1 on failure.
3313 */
3314 static int
relocate_object(Obj_Entry * obj,bool bind_now,Obj_Entry * rtldobj,int flags,RtldLockState * lockstate)3315 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
3316 int flags, RtldLockState *lockstate)
3317 {
3318
3319 if (obj->relocated)
3320 return (0);
3321 obj->relocated = true;
3322 if (obj != rtldobj)
3323 dbg("relocating \"%s\"", obj->path);
3324
3325 if (obj->symtab == NULL || obj->strtab == NULL ||
3326 !(obj->valid_hash_sysv || obj->valid_hash_gnu))
3327 dbg("object %s has no run-time symbol table", obj->path);
3328
3329 /* There are relocations to the write-protected text segment. */
3330 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
3331 return (-1);
3332
3333 /* Process the non-PLT non-IFUNC relocations. */
3334 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
3335 return (-1);
3336 reloc_relr(obj);
3337
3338 /* Re-protected the text segment. */
3339 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
3340 return (-1);
3341
3342 /* Set the special PLT or GOT entries. */
3343 init_pltgot(obj);
3344
3345 /* Process the PLT relocations. */
3346 if (reloc_plt(obj, flags, lockstate) == -1)
3347 return (-1);
3348 /* Relocate the jump slots if we are doing immediate binding. */
3349 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags,
3350 lockstate) == -1)
3351 return (-1);
3352
3353 if (!obj->mainprog && obj_enforce_relro(obj) == -1)
3354 return (-1);
3355
3356 /*
3357 * Set up the magic number and version in the Obj_Entry. These
3358 * were checked in the crt1.o from the original ElfKit, so we
3359 * set them for backward compatibility.
3360 */
3361 obj->magic = RTLD_MAGIC;
3362 obj->version = RTLD_VERSION;
3363
3364 return (0);
3365 }
3366
3367 /*
3368 * Relocate newly-loaded shared objects. The argument is a pointer to
3369 * the Obj_Entry for the first such object. All objects from the first
3370 * to the end of the list of objects are relocated. Returns 0 on success,
3371 * or -1 on failure.
3372 */
3373 static int
relocate_objects(Obj_Entry * first,bool bind_now,Obj_Entry * rtldobj,int flags,RtldLockState * lockstate)3374 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
3375 int flags, RtldLockState *lockstate)
3376 {
3377 Obj_Entry *obj;
3378 int error;
3379
3380 for (error = 0, obj = first; obj != NULL;
3381 obj = TAILQ_NEXT(obj, next)) {
3382 if (obj->marker)
3383 continue;
3384 error = relocate_object(obj, bind_now, rtldobj, flags,
3385 lockstate);
3386 if (error == -1)
3387 break;
3388 }
3389 return (error);
3390 }
3391
3392 /*
3393 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
3394 * referencing STT_GNU_IFUNC symbols is postponed till the other
3395 * relocations are done. The indirect functions specified as
3396 * ifunc are allowed to call other symbols, so we need to have
3397 * objects relocated before asking for resolution from indirects.
3398 *
3399 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
3400 * instead of the usual lazy handling of PLT slots. It is
3401 * consistent with how GNU does it.
3402 */
3403 static int
resolve_object_ifunc(Obj_Entry * obj,bool bind_now,int flags,RtldLockState * lockstate)3404 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
3405 RtldLockState *lockstate)
3406 {
3407
3408 if (obj->ifuncs_resolved)
3409 return (0);
3410 obj->ifuncs_resolved = true;
3411 if (!obj->irelative && !obj->irelative_nonplt &&
3412 !((obj->bind_now || bind_now) && obj->gnu_ifunc) &&
3413 !obj->non_plt_gnu_ifunc)
3414 return (0);
3415 if (obj_disable_relro(obj) == -1 ||
3416 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) ||
3417 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj,
3418 lockstate) == -1) ||
3419 ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
3420 reloc_gnu_ifunc(obj, flags, lockstate) == -1) ||
3421 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld,
3422 flags | SYMLOOK_IFUNC, lockstate) == -1) ||
3423 obj_enforce_relro(obj) == -1)
3424 return (-1);
3425 return (0);
3426 }
3427
3428 static int
initlist_objects_ifunc(Objlist * list,bool bind_now,int flags,RtldLockState * lockstate)3429 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
3430 RtldLockState *lockstate)
3431 {
3432 Objlist_Entry *elm;
3433 Obj_Entry *obj;
3434
3435 STAILQ_FOREACH(elm, list, link) {
3436 obj = elm->obj;
3437 if (obj->marker)
3438 continue;
3439 if (resolve_object_ifunc(obj, bind_now, flags,
3440 lockstate) == -1)
3441 return (-1);
3442 }
3443 return (0);
3444 }
3445
3446 /*
3447 * Cleanup procedure. It will be called (by the atexit mechanism) just
3448 * before the process exits.
3449 */
3450 static void
rtld_exit(void)3451 rtld_exit(void)
3452 {
3453 RtldLockState lockstate;
3454
3455 wlock_acquire(rtld_bind_lock, &lockstate);
3456 dbg("rtld_exit()");
3457 objlist_call_fini(&list_fini, NULL, &lockstate);
3458 /* No need to remove the items from the list, since we are exiting. */
3459 if (!libmap_disable)
3460 lm_fini();
3461 lock_release(rtld_bind_lock, &lockstate);
3462 }
3463
3464 static void
rtld_nop_exit(void)3465 rtld_nop_exit(void)
3466 {
3467 }
3468
3469 /*
3470 * Iterate over a search path, translate each element, and invoke the
3471 * callback on the result.
3472 */
3473 static void *
path_enumerate(const char * path,path_enum_proc callback,const char * refobj_path,void * arg)3474 path_enumerate(const char *path, path_enum_proc callback,
3475 const char *refobj_path, void *arg)
3476 {
3477 const char *trans;
3478 if (path == NULL)
3479 return (NULL);
3480
3481 path += strspn(path, ":;");
3482 while (*path != '\0') {
3483 size_t len;
3484 char *res;
3485
3486 len = strcspn(path, ":;");
3487 trans = lm_findn(refobj_path, path, len);
3488 if (trans)
3489 res = callback(trans, strlen(trans), arg);
3490 else
3491 res = callback(path, len, arg);
3492
3493 if (res != NULL)
3494 return (res);
3495
3496 path += len;
3497 path += strspn(path, ":;");
3498 }
3499
3500 return (NULL);
3501 }
3502
3503 struct try_library_args {
3504 const char *name;
3505 size_t namelen;
3506 char *buffer;
3507 size_t buflen;
3508 int fd;
3509 };
3510
3511 static void *
try_library_path(const char * dir,size_t dirlen,void * param)3512 try_library_path(const char *dir, size_t dirlen, void *param)
3513 {
3514 struct try_library_args *arg;
3515 int fd;
3516
3517 arg = param;
3518 if (*dir == '/' || trust) {
3519 char *pathname;
3520
3521 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3522 return (NULL);
3523
3524 pathname = arg->buffer;
3525 strncpy(pathname, dir, dirlen);
3526 pathname[dirlen] = '/';
3527 strcpy(pathname + dirlen + 1, arg->name);
3528
3529 dbg(" Trying \"%s\"", pathname);
3530 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3531 if (fd >= 0) {
3532 dbg(" Opened \"%s\", fd %d", pathname, fd);
3533 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3534 strcpy(pathname, arg->buffer);
3535 arg->fd = fd;
3536 return (pathname);
3537 } else {
3538 dbg(" Failed to open \"%s\": %s",
3539 pathname, rtld_strerror(errno));
3540 }
3541 }
3542 return (NULL);
3543 }
3544
3545 static char *
search_library_path(const char * name,const char * path,const char * refobj_path,int * fdp)3546 search_library_path(const char *name, const char *path,
3547 const char *refobj_path, int *fdp)
3548 {
3549 char *p;
3550 struct try_library_args arg;
3551
3552 if (path == NULL)
3553 return (NULL);
3554
3555 arg.name = name;
3556 arg.namelen = strlen(name);
3557 arg.buffer = xmalloc(PATH_MAX);
3558 arg.buflen = PATH_MAX;
3559 arg.fd = -1;
3560
3561 p = path_enumerate(path, try_library_path, refobj_path, &arg);
3562 *fdp = arg.fd;
3563
3564 free(arg.buffer);
3565
3566 return (p);
3567 }
3568
3569
3570 /*
3571 * Finds the library with the given name using the directory descriptors
3572 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3573 *
3574 * Returns a freshly-opened close-on-exec file descriptor for the library,
3575 * or -1 if the library cannot be found.
3576 */
3577 static char *
search_library_pathfds(const char * name,const char * path,int * fdp)3578 search_library_pathfds(const char *name, const char *path, int *fdp)
3579 {
3580 char *envcopy, *fdstr, *found, *last_token;
3581 size_t len;
3582 int dirfd, fd;
3583
3584 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3585
3586 /* Don't load from user-specified libdirs into setuid binaries. */
3587 if (!trust)
3588 return (NULL);
3589
3590 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3591 if (path == NULL)
3592 return (NULL);
3593
3594 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3595 if (name[0] == '/') {
3596 dbg("Absolute path (%s) passed to %s", name, __func__);
3597 return (NULL);
3598 }
3599
3600 /*
3601 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3602 * copy of the path, as strtok_r rewrites separator tokens
3603 * with '\0'.
3604 */
3605 found = NULL;
3606 envcopy = xstrdup(path);
3607 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3608 fdstr = strtok_r(NULL, ":", &last_token)) {
3609 dirfd = parse_integer(fdstr);
3610 if (dirfd < 0) {
3611 _rtld_error("failed to parse directory FD: '%s'",
3612 fdstr);
3613 break;
3614 }
3615 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3616 if (fd >= 0) {
3617 *fdp = fd;
3618 len = strlen(fdstr) + strlen(name) + 3;
3619 found = xmalloc(len);
3620 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
3621 _rtld_error("error generating '%d/%s'",
3622 dirfd, name);
3623 rtld_die();
3624 }
3625 dbg("open('%s') => %d", found, fd);
3626 break;
3627 }
3628 }
3629 free(envcopy);
3630
3631 return (found);
3632 }
3633
3634
3635 int
dlclose(void * handle)3636 dlclose(void *handle)
3637 {
3638 RtldLockState lockstate;
3639 int error;
3640
3641 wlock_acquire(rtld_bind_lock, &lockstate);
3642 error = dlclose_locked(handle, &lockstate);
3643 lock_release(rtld_bind_lock, &lockstate);
3644 return (error);
3645 }
3646
3647 static int
dlclose_locked(void * handle,RtldLockState * lockstate)3648 dlclose_locked(void *handle, RtldLockState *lockstate)
3649 {
3650 Obj_Entry *root;
3651
3652 root = dlcheck(handle);
3653 if (root == NULL)
3654 return (-1);
3655 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3656 root->path);
3657
3658 /* Unreference the object and its dependencies. */
3659 root->dl_refcount--;
3660
3661 if (root->refcount == 1) {
3662 /*
3663 * The object will be no longer referenced, so we must unload it.
3664 * First, call the fini functions.
3665 */
3666 objlist_call_fini(&list_fini, root, lockstate);
3667
3668 unref_dag(root);
3669
3670 /* Finish cleaning up the newly-unreferenced objects. */
3671 GDB_STATE(RT_DELETE,&root->linkmap);
3672 unload_object(root, lockstate);
3673 GDB_STATE(RT_CONSISTENT,NULL);
3674 } else
3675 unref_dag(root);
3676
3677 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3678 return (0);
3679 }
3680
3681 char *
dlerror(void)3682 dlerror(void)
3683 {
3684 if (*(lockinfo.dlerror_seen()) != 0)
3685 return (NULL);
3686 *lockinfo.dlerror_seen() = 1;
3687 return (lockinfo.dlerror_loc());
3688 }
3689
3690 /*
3691 * This function is deprecated and has no effect.
3692 */
3693 void
dllockinit(void * context,void * (* _lock_create)(void * context)__unused,void (* _rlock_acquire)(void * lock)__unused,void (* _wlock_acquire)(void * lock)__unused,void (* _lock_release)(void * lock)__unused,void (* _lock_destroy)(void * lock)__unused,void (* context_destroy)(void * context))3694 dllockinit(void *context,
3695 void *(*_lock_create)(void *context) __unused,
3696 void (*_rlock_acquire)(void *lock) __unused,
3697 void (*_wlock_acquire)(void *lock) __unused,
3698 void (*_lock_release)(void *lock) __unused,
3699 void (*_lock_destroy)(void *lock) __unused,
3700 void (*context_destroy)(void *context))
3701 {
3702 static void *cur_context;
3703 static void (*cur_context_destroy)(void *);
3704
3705 /* Just destroy the context from the previous call, if necessary. */
3706 if (cur_context_destroy != NULL)
3707 cur_context_destroy(cur_context);
3708 cur_context = context;
3709 cur_context_destroy = context_destroy;
3710 }
3711
3712 void *
dlopen(const char * name,int mode)3713 dlopen(const char *name, int mode)
3714 {
3715
3716 return (rtld_dlopen(name, -1, mode));
3717 }
3718
3719 void *
fdlopen(int fd,int mode)3720 fdlopen(int fd, int mode)
3721 {
3722
3723 return (rtld_dlopen(NULL, fd, mode));
3724 }
3725
3726 static void *
rtld_dlopen(const char * name,int fd,int mode)3727 rtld_dlopen(const char *name, int fd, int mode)
3728 {
3729 RtldLockState lockstate;
3730 int lo_flags;
3731
3732 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3733 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3734 if (ld_tracing != NULL) {
3735 rlock_acquire(rtld_bind_lock, &lockstate);
3736 if (sigsetjmp(lockstate.env, 0) != 0)
3737 lock_upgrade(rtld_bind_lock, &lockstate);
3738 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate));
3739 lock_release(rtld_bind_lock, &lockstate);
3740 }
3741 lo_flags = RTLD_LO_DLOPEN;
3742 if (mode & RTLD_NODELETE)
3743 lo_flags |= RTLD_LO_NODELETE;
3744 if (mode & RTLD_NOLOAD)
3745 lo_flags |= RTLD_LO_NOLOAD;
3746 if (mode & RTLD_DEEPBIND)
3747 lo_flags |= RTLD_LO_DEEPBIND;
3748 if (ld_tracing != NULL)
3749 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS;
3750
3751 return (dlopen_object(name, fd, obj_main, lo_flags,
3752 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3753 }
3754
3755 static void
dlopen_cleanup(Obj_Entry * obj,RtldLockState * lockstate)3756 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3757 {
3758
3759 obj->dl_refcount--;
3760 unref_dag(obj);
3761 if (obj->refcount == 0)
3762 unload_object(obj, lockstate);
3763 }
3764
3765 static Obj_Entry *
dlopen_object(const char * name,int fd,Obj_Entry * refobj,int lo_flags,int mode,RtldLockState * lockstate)3766 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3767 int mode, RtldLockState *lockstate)
3768 {
3769 Obj_Entry *obj;
3770 Objlist initlist;
3771 RtldLockState mlockstate;
3772 int result;
3773
3774 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x",
3775 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" :
3776 refobj->path, lo_flags, mode);
3777 objlist_init(&initlist);
3778
3779 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3780 wlock_acquire(rtld_bind_lock, &mlockstate);
3781 lockstate = &mlockstate;
3782 }
3783 GDB_STATE(RT_ADD,NULL);
3784
3785 obj = NULL;
3786 if (name == NULL && fd == -1) {
3787 obj = obj_main;
3788 obj->refcount++;
3789 } else {
3790 obj = load_object(name, fd, refobj, lo_flags);
3791 }
3792
3793 if (obj) {
3794 obj->dl_refcount++;
3795 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3796 objlist_push_tail(&list_global, obj);
3797
3798 if (!obj->init_done) {
3799 /* We loaded something new and have to init something. */
3800 if ((lo_flags & RTLD_LO_DEEPBIND) != 0)
3801 obj->deepbind = true;
3802 result = 0;
3803 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 &&
3804 obj->static_tls && !allocate_tls_offset(obj)) {
3805 _rtld_error("%s: No space available "
3806 "for static Thread Local Storage", obj->path);
3807 result = -1;
3808 }
3809 if (result != -1)
3810 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN |
3811 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE));
3812 init_dag(obj);
3813 ref_dag(obj);
3814 if (result != -1)
3815 result = rtld_verify_versions(&obj->dagmembers);
3816 if (result != -1 && ld_tracing)
3817 goto trace;
3818 if (result == -1 || relocate_object_dag(obj,
3819 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3820 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3821 lockstate) == -1) {
3822 dlopen_cleanup(obj, lockstate);
3823 obj = NULL;
3824 } else if (lo_flags & RTLD_LO_EARLY) {
3825 /*
3826 * Do not call the init functions for early loaded
3827 * filtees. The image is still not initialized enough
3828 * for them to work.
3829 *
3830 * Our object is found by the global object list and
3831 * will be ordered among all init calls done right
3832 * before transferring control to main.
3833 */
3834 } else {
3835 /* Make list of init functions to call. */
3836 initlist_add_objects(obj, obj, &initlist);
3837 }
3838 /*
3839 * Process all no_delete or global objects here, given
3840 * them own DAGs to prevent their dependencies from being
3841 * unloaded. This has to be done after we have loaded all
3842 * of the dependencies, so that we do not miss any.
3843 */
3844 if (obj != NULL)
3845 process_z(obj);
3846 } else {
3847 /*
3848 * Bump the reference counts for objects on this DAG. If
3849 * this is the first dlopen() call for the object that was
3850 * already loaded as a dependency, initialize the dag
3851 * starting at it.
3852 */
3853 init_dag(obj);
3854 ref_dag(obj);
3855
3856 if ((lo_flags & RTLD_LO_TRACE) != 0)
3857 goto trace;
3858 }
3859 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3860 obj->z_nodelete) && !obj->ref_nodel) {
3861 dbg("obj %s nodelete", obj->path);
3862 ref_dag(obj);
3863 obj->z_nodelete = obj->ref_nodel = true;
3864 }
3865 }
3866
3867 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3868 name);
3869 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3870
3871 if ((lo_flags & RTLD_LO_EARLY) == 0) {
3872 map_stacks_exec(lockstate);
3873 if (obj != NULL)
3874 distribute_static_tls(&initlist, lockstate);
3875 }
3876
3877 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3878 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3879 lockstate) == -1) {
3880 objlist_clear(&initlist);
3881 dlopen_cleanup(obj, lockstate);
3882 if (lockstate == &mlockstate)
3883 lock_release(rtld_bind_lock, lockstate);
3884 return (NULL);
3885 }
3886
3887 if (!(lo_flags & RTLD_LO_EARLY)) {
3888 /* Call the init functions. */
3889 objlist_call_init(&initlist, lockstate);
3890 }
3891 objlist_clear(&initlist);
3892 if (lockstate == &mlockstate)
3893 lock_release(rtld_bind_lock, lockstate);
3894 return (obj);
3895 trace:
3896 trace_loaded_objects(obj, false);
3897 if (lockstate == &mlockstate)
3898 lock_release(rtld_bind_lock, lockstate);
3899 exit(0);
3900 }
3901
3902 static void *
do_dlsym(void * handle,const char * name,void * retaddr,const Ver_Entry * ve,int flags)3903 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3904 int flags)
3905 {
3906 DoneList donelist;
3907 const Obj_Entry *obj, *defobj;
3908 const Elf_Sym *def;
3909 SymLook req;
3910 RtldLockState lockstate;
3911 tls_index ti;
3912 void *sym;
3913 int res;
3914
3915 def = NULL;
3916 defobj = NULL;
3917 symlook_init(&req, name);
3918 req.ventry = ve;
3919 req.flags = flags | SYMLOOK_IN_PLT;
3920 req.lockstate = &lockstate;
3921
3922 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3923 rlock_acquire(rtld_bind_lock, &lockstate);
3924 if (sigsetjmp(lockstate.env, 0) != 0)
3925 lock_upgrade(rtld_bind_lock, &lockstate);
3926 if (handle == NULL || handle == RTLD_NEXT ||
3927 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3928
3929 if ((obj = obj_from_addr(retaddr)) == NULL) {
3930 _rtld_error("Cannot determine caller's shared object");
3931 lock_release(rtld_bind_lock, &lockstate);
3932 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3933 return (NULL);
3934 }
3935 if (handle == NULL) { /* Just the caller's shared object. */
3936 res = symlook_obj(&req, obj);
3937 if (res == 0) {
3938 def = req.sym_out;
3939 defobj = req.defobj_out;
3940 }
3941 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3942 handle == RTLD_SELF) { /* ... caller included */
3943 if (handle == RTLD_NEXT)
3944 obj = globallist_next(obj);
3945 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3946 if (obj->marker)
3947 continue;
3948 res = symlook_obj(&req, obj);
3949 if (res == 0) {
3950 if (def == NULL || (ld_dynamic_weak &&
3951 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK)) {
3952 def = req.sym_out;
3953 defobj = req.defobj_out;
3954 if (!ld_dynamic_weak ||
3955 ELF_ST_BIND(def->st_info) != STB_WEAK)
3956 break;
3957 }
3958 }
3959 }
3960 /*
3961 * Search the dynamic linker itself, and possibly resolve the
3962 * symbol from there. This is how the application links to
3963 * dynamic linker services such as dlopen.
3964 * Note that we ignore ld_dynamic_weak == false case,
3965 * always overriding weak symbols by rtld definitions.
3966 */
3967 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3968 res = symlook_obj(&req, &obj_rtld);
3969 if (res == 0) {
3970 def = req.sym_out;
3971 defobj = req.defobj_out;
3972 }
3973 }
3974 } else {
3975 assert(handle == RTLD_DEFAULT);
3976 res = symlook_default(&req, obj);
3977 if (res == 0) {
3978 defobj = req.defobj_out;
3979 def = req.sym_out;
3980 }
3981 }
3982 } else {
3983 if ((obj = dlcheck(handle)) == NULL) {
3984 lock_release(rtld_bind_lock, &lockstate);
3985 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3986 return (NULL);
3987 }
3988
3989 donelist_init(&donelist);
3990 if (obj->mainprog) {
3991 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3992 res = symlook_global(&req, &donelist);
3993 if (res == 0) {
3994 def = req.sym_out;
3995 defobj = req.defobj_out;
3996 }
3997 /*
3998 * Search the dynamic linker itself, and possibly resolve the
3999 * symbol from there. This is how the application links to
4000 * dynamic linker services such as dlopen.
4001 */
4002 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
4003 res = symlook_obj(&req, &obj_rtld);
4004 if (res == 0) {
4005 def = req.sym_out;
4006 defobj = req.defobj_out;
4007 }
4008 }
4009 }
4010 else {
4011 /* Search the whole DAG rooted at the given object. */
4012 res = symlook_list(&req, &obj->dagmembers, &donelist);
4013 if (res == 0) {
4014 def = req.sym_out;
4015 defobj = req.defobj_out;
4016 }
4017 }
4018 }
4019
4020 if (def != NULL) {
4021 lock_release(rtld_bind_lock, &lockstate);
4022
4023 /*
4024 * The value required by the caller is derived from the value
4025 * of the symbol. this is simply the relocated value of the
4026 * symbol.
4027 */
4028 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
4029 sym = make_function_pointer(def, defobj);
4030 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
4031 sym = rtld_resolve_ifunc(defobj, def);
4032 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
4033 ti.ti_module = defobj->tlsindex;
4034 ti.ti_offset = def->st_value;
4035 sym = __tls_get_addr(&ti);
4036 } else
4037 sym = defobj->relocbase + def->st_value;
4038 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
4039 return (sym);
4040 }
4041
4042 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
4043 ve != NULL ? ve->name : "");
4044 lock_release(rtld_bind_lock, &lockstate);
4045 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
4046 return (NULL);
4047 }
4048
4049 void *
dlsym(void * handle,const char * name)4050 dlsym(void *handle, const char *name)
4051 {
4052 return (do_dlsym(handle, name, __builtin_return_address(0), NULL,
4053 SYMLOOK_DLSYM));
4054 }
4055
4056 dlfunc_t
dlfunc(void * handle,const char * name)4057 dlfunc(void *handle, const char *name)
4058 {
4059 union {
4060 void *d;
4061 dlfunc_t f;
4062 } rv;
4063
4064 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
4065 SYMLOOK_DLSYM);
4066 return (rv.f);
4067 }
4068
4069 void *
dlvsym(void * handle,const char * name,const char * version)4070 dlvsym(void *handle, const char *name, const char *version)
4071 {
4072 Ver_Entry ventry;
4073
4074 ventry.name = version;
4075 ventry.file = NULL;
4076 ventry.hash = elf_hash(version);
4077 ventry.flags= 0;
4078 return (do_dlsym(handle, name, __builtin_return_address(0), &ventry,
4079 SYMLOOK_DLSYM));
4080 }
4081
4082 int
_rtld_addr_phdr(const void * addr,struct dl_phdr_info * phdr_info)4083 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
4084 {
4085 const Obj_Entry *obj;
4086 RtldLockState lockstate;
4087
4088 rlock_acquire(rtld_bind_lock, &lockstate);
4089 obj = obj_from_addr(addr);
4090 if (obj == NULL) {
4091 _rtld_error("No shared object contains address");
4092 lock_release(rtld_bind_lock, &lockstate);
4093 return (0);
4094 }
4095 rtld_fill_dl_phdr_info(obj, phdr_info);
4096 lock_release(rtld_bind_lock, &lockstate);
4097 return (1);
4098 }
4099
4100 int
dladdr(const void * addr,Dl_info * info)4101 dladdr(const void *addr, Dl_info *info)
4102 {
4103 const Obj_Entry *obj;
4104 const Elf_Sym *def;
4105 void *symbol_addr;
4106 unsigned long symoffset;
4107 RtldLockState lockstate;
4108
4109 rlock_acquire(rtld_bind_lock, &lockstate);
4110 obj = obj_from_addr(addr);
4111 if (obj == NULL) {
4112 _rtld_error("No shared object contains address");
4113 lock_release(rtld_bind_lock, &lockstate);
4114 return (0);
4115 }
4116 info->dli_fname = obj->path;
4117 info->dli_fbase = obj->mapbase;
4118 info->dli_saddr = (void *)0;
4119 info->dli_sname = NULL;
4120
4121 /*
4122 * Walk the symbol list looking for the symbol whose address is
4123 * closest to the address sent in.
4124 */
4125 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
4126 def = obj->symtab + symoffset;
4127
4128 /*
4129 * For skip the symbol if st_shndx is either SHN_UNDEF or
4130 * SHN_COMMON.
4131 */
4132 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
4133 continue;
4134
4135 /*
4136 * If the symbol is greater than the specified address, or if it
4137 * is further away from addr than the current nearest symbol,
4138 * then reject it.
4139 */
4140 symbol_addr = obj->relocbase + def->st_value;
4141 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
4142 continue;
4143
4144 /* Update our idea of the nearest symbol. */
4145 info->dli_sname = obj->strtab + def->st_name;
4146 info->dli_saddr = symbol_addr;
4147
4148 /* Exact match? */
4149 if (info->dli_saddr == addr)
4150 break;
4151 }
4152 lock_release(rtld_bind_lock, &lockstate);
4153 return (1);
4154 }
4155
4156 int
dlinfo(void * handle,int request,void * p)4157 dlinfo(void *handle, int request, void *p)
4158 {
4159 const Obj_Entry *obj;
4160 RtldLockState lockstate;
4161 int error;
4162
4163 rlock_acquire(rtld_bind_lock, &lockstate);
4164
4165 if (handle == NULL || handle == RTLD_SELF) {
4166 void *retaddr;
4167
4168 retaddr = __builtin_return_address(0); /* __GNUC__ only */
4169 if ((obj = obj_from_addr(retaddr)) == NULL)
4170 _rtld_error("Cannot determine caller's shared object");
4171 } else
4172 obj = dlcheck(handle);
4173
4174 if (obj == NULL) {
4175 lock_release(rtld_bind_lock, &lockstate);
4176 return (-1);
4177 }
4178
4179 error = 0;
4180 switch (request) {
4181 case RTLD_DI_LINKMAP:
4182 *((struct link_map const **)p) = &obj->linkmap;
4183 break;
4184 case RTLD_DI_ORIGIN:
4185 error = rtld_dirname(obj->path, p);
4186 break;
4187
4188 case RTLD_DI_SERINFOSIZE:
4189 case RTLD_DI_SERINFO:
4190 error = do_search_info(obj, request, (struct dl_serinfo *)p);
4191 break;
4192
4193 default:
4194 _rtld_error("Invalid request %d passed to dlinfo()", request);
4195 error = -1;
4196 }
4197
4198 lock_release(rtld_bind_lock, &lockstate);
4199
4200 return (error);
4201 }
4202
4203 static void
rtld_fill_dl_phdr_info(const Obj_Entry * obj,struct dl_phdr_info * phdr_info)4204 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
4205 {
4206 uintptr_t **dtvp;
4207
4208 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
4209 phdr_info->dlpi_name = obj->path;
4210 phdr_info->dlpi_phdr = obj->phdr;
4211 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
4212 phdr_info->dlpi_tls_modid = obj->tlsindex;
4213 dtvp = &_tcb_get()->tcb_dtv;
4214 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(dtvp,
4215 obj->tlsindex, 0, true) + TLS_DTV_OFFSET;
4216 phdr_info->dlpi_adds = obj_loads;
4217 phdr_info->dlpi_subs = obj_loads - obj_count;
4218 }
4219
4220 int
dl_iterate_phdr(__dl_iterate_hdr_callback callback,void * param)4221 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
4222 {
4223 struct dl_phdr_info phdr_info;
4224 Obj_Entry *obj, marker;
4225 RtldLockState bind_lockstate, phdr_lockstate;
4226 int error;
4227
4228 init_marker(&marker);
4229 error = 0;
4230
4231 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
4232 wlock_acquire(rtld_bind_lock, &bind_lockstate);
4233 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
4234 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
4235 rtld_fill_dl_phdr_info(obj, &phdr_info);
4236 hold_object(obj);
4237 lock_release(rtld_bind_lock, &bind_lockstate);
4238
4239 error = callback(&phdr_info, sizeof phdr_info, param);
4240
4241 wlock_acquire(rtld_bind_lock, &bind_lockstate);
4242 unhold_object(obj);
4243 obj = globallist_next(&marker);
4244 TAILQ_REMOVE(&obj_list, &marker, next);
4245 if (error != 0) {
4246 lock_release(rtld_bind_lock, &bind_lockstate);
4247 lock_release(rtld_phdr_lock, &phdr_lockstate);
4248 return (error);
4249 }
4250 }
4251
4252 if (error == 0) {
4253 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
4254 lock_release(rtld_bind_lock, &bind_lockstate);
4255 error = callback(&phdr_info, sizeof(phdr_info), param);
4256 }
4257 lock_release(rtld_phdr_lock, &phdr_lockstate);
4258 return (error);
4259 }
4260
4261 static void *
fill_search_info(const char * dir,size_t dirlen,void * param)4262 fill_search_info(const char *dir, size_t dirlen, void *param)
4263 {
4264 struct fill_search_info_args *arg;
4265
4266 arg = param;
4267
4268 if (arg->request == RTLD_DI_SERINFOSIZE) {
4269 arg->serinfo->dls_cnt ++;
4270 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
4271 } else {
4272 struct dl_serpath *s_entry;
4273
4274 s_entry = arg->serpath;
4275 s_entry->dls_name = arg->strspace;
4276 s_entry->dls_flags = arg->flags;
4277
4278 strncpy(arg->strspace, dir, dirlen);
4279 arg->strspace[dirlen] = '\0';
4280
4281 arg->strspace += dirlen + 1;
4282 arg->serpath++;
4283 }
4284
4285 return (NULL);
4286 }
4287
4288 static int
do_search_info(const Obj_Entry * obj,int request,struct dl_serinfo * info)4289 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
4290 {
4291 struct dl_serinfo _info;
4292 struct fill_search_info_args args;
4293
4294 args.request = RTLD_DI_SERINFOSIZE;
4295 args.serinfo = &_info;
4296
4297 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
4298 _info.dls_cnt = 0;
4299
4300 path_enumerate(obj->rpath, fill_search_info, NULL, &args);
4301 path_enumerate(ld_library_path, fill_search_info, NULL, &args);
4302 path_enumerate(obj->runpath, fill_search_info, NULL, &args);
4303 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args);
4304 if (!obj->z_nodeflib)
4305 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args);
4306
4307
4308 if (request == RTLD_DI_SERINFOSIZE) {
4309 info->dls_size = _info.dls_size;
4310 info->dls_cnt = _info.dls_cnt;
4311 return (0);
4312 }
4313
4314 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
4315 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
4316 return (-1);
4317 }
4318
4319 args.request = RTLD_DI_SERINFO;
4320 args.serinfo = info;
4321 args.serpath = &info->dls_serpath[0];
4322 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
4323
4324 args.flags = LA_SER_RUNPATH;
4325 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL)
4326 return (-1);
4327
4328 args.flags = LA_SER_LIBPATH;
4329 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL)
4330 return (-1);
4331
4332 args.flags = LA_SER_RUNPATH;
4333 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL)
4334 return (-1);
4335
4336 args.flags = LA_SER_CONFIG;
4337 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args)
4338 != NULL)
4339 return (-1);
4340
4341 args.flags = LA_SER_DEFAULT;
4342 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path,
4343 fill_search_info, NULL, &args) != NULL)
4344 return (-1);
4345 return (0);
4346 }
4347
4348 static int
rtld_dirname(const char * path,char * bname)4349 rtld_dirname(const char *path, char *bname)
4350 {
4351 const char *endp;
4352
4353 /* Empty or NULL string gets treated as "." */
4354 if (path == NULL || *path == '\0') {
4355 bname[0] = '.';
4356 bname[1] = '\0';
4357 return (0);
4358 }
4359
4360 /* Strip trailing slashes */
4361 endp = path + strlen(path) - 1;
4362 while (endp > path && *endp == '/')
4363 endp--;
4364
4365 /* Find the start of the dir */
4366 while (endp > path && *endp != '/')
4367 endp--;
4368
4369 /* Either the dir is "/" or there are no slashes */
4370 if (endp == path) {
4371 bname[0] = *endp == '/' ? '/' : '.';
4372 bname[1] = '\0';
4373 return (0);
4374 } else {
4375 do {
4376 endp--;
4377 } while (endp > path && *endp == '/');
4378 }
4379
4380 if (endp - path + 2 > PATH_MAX)
4381 {
4382 _rtld_error("Filename is too long: %s", path);
4383 return(-1);
4384 }
4385
4386 strncpy(bname, path, endp - path + 1);
4387 bname[endp - path + 1] = '\0';
4388 return (0);
4389 }
4390
4391 static int
rtld_dirname_abs(const char * path,char * base)4392 rtld_dirname_abs(const char *path, char *base)
4393 {
4394 char *last;
4395
4396 if (realpath(path, base) == NULL) {
4397 _rtld_error("realpath \"%s\" failed (%s)", path,
4398 rtld_strerror(errno));
4399 return (-1);
4400 }
4401 dbg("%s -> %s", path, base);
4402 last = strrchr(base, '/');
4403 if (last == NULL) {
4404 _rtld_error("non-abs result from realpath \"%s\"", path);
4405 return (-1);
4406 }
4407 if (last != base)
4408 *last = '\0';
4409 return (0);
4410 }
4411
4412 static void
linkmap_add(Obj_Entry * obj)4413 linkmap_add(Obj_Entry *obj)
4414 {
4415 struct link_map *l, *prev;
4416
4417 l = &obj->linkmap;
4418 l->l_name = obj->path;
4419 l->l_base = obj->mapbase;
4420 l->l_ld = obj->dynamic;
4421 l->l_addr = obj->relocbase;
4422
4423 if (r_debug.r_map == NULL) {
4424 r_debug.r_map = l;
4425 return;
4426 }
4427
4428 /*
4429 * Scan to the end of the list, but not past the entry for the
4430 * dynamic linker, which we want to keep at the very end.
4431 */
4432 for (prev = r_debug.r_map;
4433 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
4434 prev = prev->l_next)
4435 ;
4436
4437 /* Link in the new entry. */
4438 l->l_prev = prev;
4439 l->l_next = prev->l_next;
4440 if (l->l_next != NULL)
4441 l->l_next->l_prev = l;
4442 prev->l_next = l;
4443 }
4444
4445 static void
linkmap_delete(Obj_Entry * obj)4446 linkmap_delete(Obj_Entry *obj)
4447 {
4448 struct link_map *l;
4449
4450 l = &obj->linkmap;
4451 if (l->l_prev == NULL) {
4452 if ((r_debug.r_map = l->l_next) != NULL)
4453 l->l_next->l_prev = NULL;
4454 return;
4455 }
4456
4457 if ((l->l_prev->l_next = l->l_next) != NULL)
4458 l->l_next->l_prev = l->l_prev;
4459 }
4460
4461 /*
4462 * Function for the debugger to set a breakpoint on to gain control.
4463 *
4464 * The two parameters allow the debugger to easily find and determine
4465 * what the runtime loader is doing and to whom it is doing it.
4466 *
4467 * When the loadhook trap is hit (r_debug_state, set at program
4468 * initialization), the arguments can be found on the stack:
4469 *
4470 * +8 struct link_map *m
4471 * +4 struct r_debug *rd
4472 * +0 RetAddr
4473 */
4474 void
r_debug_state(struct r_debug * rd __unused,struct link_map * m __unused)4475 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused)
4476 {
4477 /*
4478 * The following is a hack to force the compiler to emit calls to
4479 * this function, even when optimizing. If the function is empty,
4480 * the compiler is not obliged to emit any code for calls to it,
4481 * even when marked __noinline. However, gdb depends on those
4482 * calls being made.
4483 */
4484 __compiler_membar();
4485 }
4486
4487 /*
4488 * A function called after init routines have completed. This can be used to
4489 * break before a program's entry routine is called, and can be used when
4490 * main is not available in the symbol table.
4491 */
4492 void
_r_debug_postinit(struct link_map * m __unused)4493 _r_debug_postinit(struct link_map *m __unused)
4494 {
4495
4496 /* See r_debug_state(). */
4497 __compiler_membar();
4498 }
4499
4500 static void
release_object(Obj_Entry * obj)4501 release_object(Obj_Entry *obj)
4502 {
4503
4504 if (obj->holdcount > 0) {
4505 obj->unholdfree = true;
4506 return;
4507 }
4508 munmap(obj->mapbase, obj->mapsize);
4509 linkmap_delete(obj);
4510 obj_free(obj);
4511 }
4512
4513 /*
4514 * Get address of the pointer variable in the main program.
4515 * Prefer non-weak symbol over the weak one.
4516 */
4517 static const void **
get_program_var_addr(const char * name,RtldLockState * lockstate)4518 get_program_var_addr(const char *name, RtldLockState *lockstate)
4519 {
4520 SymLook req;
4521 DoneList donelist;
4522
4523 symlook_init(&req, name);
4524 req.lockstate = lockstate;
4525 donelist_init(&donelist);
4526 if (symlook_global(&req, &donelist) != 0)
4527 return (NULL);
4528 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4529 return ((const void **)make_function_pointer(req.sym_out,
4530 req.defobj_out));
4531 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4532 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
4533 else
4534 return ((const void **)(req.defobj_out->relocbase +
4535 req.sym_out->st_value));
4536 }
4537
4538 /*
4539 * Set a pointer variable in the main program to the given value. This
4540 * is used to set key variables such as "environ" before any of the
4541 * init functions are called.
4542 */
4543 static void
set_program_var(const char * name,const void * value)4544 set_program_var(const char *name, const void *value)
4545 {
4546 const void **addr;
4547
4548 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4549 dbg("\"%s\": *%p <-- %p", name, addr, value);
4550 *addr = value;
4551 }
4552 }
4553
4554 /*
4555 * Search the global objects, including dependencies and main object,
4556 * for the given symbol.
4557 */
4558 static int
symlook_global(SymLook * req,DoneList * donelist)4559 symlook_global(SymLook *req, DoneList *donelist)
4560 {
4561 SymLook req1;
4562 const Objlist_Entry *elm;
4563 int res;
4564
4565 symlook_init_from_req(&req1, req);
4566
4567 /* Search all objects loaded at program start up. */
4568 if (req->defobj_out == NULL || (ld_dynamic_weak &&
4569 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) {
4570 res = symlook_list(&req1, &list_main, donelist);
4571 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL ||
4572 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4573 req->sym_out = req1.sym_out;
4574 req->defobj_out = req1.defobj_out;
4575 assert(req->defobj_out != NULL);
4576 }
4577 }
4578
4579 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4580 STAILQ_FOREACH(elm, &list_global, link) {
4581 if (req->defobj_out != NULL && (!ld_dynamic_weak ||
4582 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK))
4583 break;
4584 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4585 if (res == 0 && (req->defobj_out == NULL ||
4586 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4587 req->sym_out = req1.sym_out;
4588 req->defobj_out = req1.defobj_out;
4589 assert(req->defobj_out != NULL);
4590 }
4591 }
4592
4593 return (req->sym_out != NULL ? 0 : ESRCH);
4594 }
4595
4596 /*
4597 * Given a symbol name in a referencing object, find the corresponding
4598 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4599 * no definition was found. Returns a pointer to the Obj_Entry of the
4600 * defining object via the reference parameter DEFOBJ_OUT.
4601 */
4602 static int
symlook_default(SymLook * req,const Obj_Entry * refobj)4603 symlook_default(SymLook *req, const Obj_Entry *refobj)
4604 {
4605 DoneList donelist;
4606 const Objlist_Entry *elm;
4607 SymLook req1;
4608 int res;
4609
4610 donelist_init(&donelist);
4611 symlook_init_from_req(&req1, req);
4612
4613 /*
4614 * Look first in the referencing object if linked symbolically,
4615 * and similarly handle protected symbols.
4616 */
4617 res = symlook_obj(&req1, refobj);
4618 if (res == 0 && (refobj->symbolic ||
4619 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) {
4620 req->sym_out = req1.sym_out;
4621 req->defobj_out = req1.defobj_out;
4622 assert(req->defobj_out != NULL);
4623 }
4624 if (refobj->symbolic || req->defobj_out != NULL)
4625 donelist_check(&donelist, refobj);
4626
4627 if (!refobj->deepbind)
4628 symlook_global(req, &donelist);
4629
4630 /* Search all dlopened DAGs containing the referencing object. */
4631 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4632 if (req->sym_out != NULL && (!ld_dynamic_weak ||
4633 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK))
4634 break;
4635 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4636 if (res == 0 && (req->sym_out == NULL ||
4637 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4638 req->sym_out = req1.sym_out;
4639 req->defobj_out = req1.defobj_out;
4640 assert(req->defobj_out != NULL);
4641 }
4642 }
4643
4644 if (refobj->deepbind)
4645 symlook_global(req, &donelist);
4646
4647 /*
4648 * Search the dynamic linker itself, and possibly resolve the
4649 * symbol from there. This is how the application links to
4650 * dynamic linker services such as dlopen.
4651 */
4652 if (req->sym_out == NULL ||
4653 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4654 res = symlook_obj(&req1, &obj_rtld);
4655 if (res == 0) {
4656 req->sym_out = req1.sym_out;
4657 req->defobj_out = req1.defobj_out;
4658 assert(req->defobj_out != NULL);
4659 }
4660 }
4661
4662 return (req->sym_out != NULL ? 0 : ESRCH);
4663 }
4664
4665 static int
symlook_list(SymLook * req,const Objlist * objlist,DoneList * dlp)4666 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4667 {
4668 const Elf_Sym *def;
4669 const Obj_Entry *defobj;
4670 const Objlist_Entry *elm;
4671 SymLook req1;
4672 int res;
4673
4674 def = NULL;
4675 defobj = NULL;
4676 STAILQ_FOREACH(elm, objlist, link) {
4677 if (donelist_check(dlp, elm->obj))
4678 continue;
4679 symlook_init_from_req(&req1, req);
4680 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4681 if (def == NULL || (ld_dynamic_weak &&
4682 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4683 def = req1.sym_out;
4684 defobj = req1.defobj_out;
4685 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK)
4686 break;
4687 }
4688 }
4689 }
4690 if (def != NULL) {
4691 req->sym_out = def;
4692 req->defobj_out = defobj;
4693 return (0);
4694 }
4695 return (ESRCH);
4696 }
4697
4698 /*
4699 * Search the chain of DAGS cointed to by the given Needed_Entry
4700 * for a symbol of the given name. Each DAG is scanned completely
4701 * before advancing to the next one. Returns a pointer to the symbol,
4702 * or NULL if no definition was found.
4703 */
4704 static int
symlook_needed(SymLook * req,const Needed_Entry * needed,DoneList * dlp)4705 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4706 {
4707 const Elf_Sym *def;
4708 const Needed_Entry *n;
4709 const Obj_Entry *defobj;
4710 SymLook req1;
4711 int res;
4712
4713 def = NULL;
4714 defobj = NULL;
4715 symlook_init_from_req(&req1, req);
4716 for (n = needed; n != NULL; n = n->next) {
4717 if (n->obj == NULL ||
4718 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
4719 continue;
4720 if (def == NULL || (ld_dynamic_weak &&
4721 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4722 def = req1.sym_out;
4723 defobj = req1.defobj_out;
4724 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK)
4725 break;
4726 }
4727 }
4728 if (def != NULL) {
4729 req->sym_out = def;
4730 req->defobj_out = defobj;
4731 return (0);
4732 }
4733 return (ESRCH);
4734 }
4735
4736 static int
symlook_obj_load_filtees(SymLook * req,SymLook * req1,const Obj_Entry * obj,Needed_Entry * needed)4737 symlook_obj_load_filtees(SymLook *req, SymLook *req1, const Obj_Entry *obj,
4738 Needed_Entry *needed)
4739 {
4740 DoneList donelist;
4741 int flags;
4742
4743 flags = (req->flags & SYMLOOK_EARLY) != 0 ? RTLD_LO_EARLY : 0;
4744 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4745 donelist_init(&donelist);
4746 symlook_init_from_req(req1, req);
4747 return (symlook_needed(req1, needed, &donelist));
4748 }
4749
4750 /*
4751 * Search the symbol table of a single shared object for a symbol of
4752 * the given name and version, if requested. Returns a pointer to the
4753 * symbol, or NULL if no definition was found. If the object is
4754 * filter, return filtered symbol from filtee.
4755 *
4756 * The symbol's hash value is passed in for efficiency reasons; that
4757 * eliminates many recomputations of the hash value.
4758 */
4759 int
symlook_obj(SymLook * req,const Obj_Entry * obj)4760 symlook_obj(SymLook *req, const Obj_Entry *obj)
4761 {
4762 SymLook req1;
4763 int res, mres;
4764
4765 /*
4766 * If there is at least one valid hash at this point, we prefer to
4767 * use the faster GNU version if available.
4768 */
4769 if (obj->valid_hash_gnu)
4770 mres = symlook_obj1_gnu(req, obj);
4771 else if (obj->valid_hash_sysv)
4772 mres = symlook_obj1_sysv(req, obj);
4773 else
4774 return (EINVAL);
4775
4776 if (mres == 0) {
4777 if (obj->needed_filtees != NULL) {
4778 res = symlook_obj_load_filtees(req, &req1, obj,
4779 obj->needed_filtees);
4780 if (res == 0) {
4781 req->sym_out = req1.sym_out;
4782 req->defobj_out = req1.defobj_out;
4783 }
4784 return (res);
4785 }
4786 if (obj->needed_aux_filtees != NULL) {
4787 res = symlook_obj_load_filtees(req, &req1, obj,
4788 obj->needed_aux_filtees);
4789 if (res == 0) {
4790 req->sym_out = req1.sym_out;
4791 req->defobj_out = req1.defobj_out;
4792 return (res);
4793 }
4794 }
4795 }
4796 return (mres);
4797 }
4798
4799 /* Symbol match routine common to both hash functions */
4800 static bool
matched_symbol(SymLook * req,const Obj_Entry * obj,Sym_Match_Result * result,const unsigned long symnum)4801 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4802 const unsigned long symnum)
4803 {
4804 Elf_Versym verndx;
4805 const Elf_Sym *symp;
4806 const char *strp;
4807
4808 symp = obj->symtab + symnum;
4809 strp = obj->strtab + symp->st_name;
4810
4811 switch (ELF_ST_TYPE(symp->st_info)) {
4812 case STT_FUNC:
4813 case STT_NOTYPE:
4814 case STT_OBJECT:
4815 case STT_COMMON:
4816 case STT_GNU_IFUNC:
4817 if (symp->st_value == 0)
4818 return (false);
4819 /* fallthrough */
4820 case STT_TLS:
4821 if (symp->st_shndx != SHN_UNDEF)
4822 break;
4823 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4824 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4825 break;
4826 /* fallthrough */
4827 default:
4828 return (false);
4829 }
4830 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4831 return (false);
4832
4833 if (req->ventry == NULL) {
4834 if (obj->versyms != NULL) {
4835 verndx = VER_NDX(obj->versyms[symnum]);
4836 if (verndx > obj->vernum) {
4837 _rtld_error(
4838 "%s: symbol %s references wrong version %d",
4839 obj->path, obj->strtab + symnum, verndx);
4840 return (false);
4841 }
4842 /*
4843 * If we are not called from dlsym (i.e. this
4844 * is a normal relocation from unversioned
4845 * binary), accept the symbol immediately if
4846 * it happens to have first version after this
4847 * shared object became versioned. Otherwise,
4848 * if symbol is versioned and not hidden,
4849 * remember it. If it is the only symbol with
4850 * this name exported by the shared object, it
4851 * will be returned as a match by the calling
4852 * function. If symbol is global (verndx < 2)
4853 * accept it unconditionally.
4854 */
4855 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4856 verndx == VER_NDX_GIVEN) {
4857 result->sym_out = symp;
4858 return (true);
4859 }
4860 else if (verndx >= VER_NDX_GIVEN) {
4861 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4862 == 0) {
4863 if (result->vsymp == NULL)
4864 result->vsymp = symp;
4865 result->vcount++;
4866 }
4867 return (false);
4868 }
4869 }
4870 result->sym_out = symp;
4871 return (true);
4872 }
4873 if (obj->versyms == NULL) {
4874 if (object_match_name(obj, req->ventry->name)) {
4875 _rtld_error("%s: object %s should provide version %s "
4876 "for symbol %s", obj_rtld.path, obj->path,
4877 req->ventry->name, obj->strtab + symnum);
4878 return (false);
4879 }
4880 } else {
4881 verndx = VER_NDX(obj->versyms[symnum]);
4882 if (verndx > obj->vernum) {
4883 _rtld_error("%s: symbol %s references wrong version %d",
4884 obj->path, obj->strtab + symnum, verndx);
4885 return (false);
4886 }
4887 if (obj->vertab[verndx].hash != req->ventry->hash ||
4888 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4889 /*
4890 * Version does not match. Look if this is a
4891 * global symbol and if it is not hidden. If
4892 * global symbol (verndx < 2) is available,
4893 * use it. Do not return symbol if we are
4894 * called by dlvsym, because dlvsym looks for
4895 * a specific version and default one is not
4896 * what dlvsym wants.
4897 */
4898 if ((req->flags & SYMLOOK_DLSYM) ||
4899 (verndx >= VER_NDX_GIVEN) ||
4900 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4901 return (false);
4902 }
4903 }
4904 result->sym_out = symp;
4905 return (true);
4906 }
4907
4908 /*
4909 * Search for symbol using SysV hash function.
4910 * obj->buckets is known not to be NULL at this point; the test for this was
4911 * performed with the obj->valid_hash_sysv assignment.
4912 */
4913 static int
symlook_obj1_sysv(SymLook * req,const Obj_Entry * obj)4914 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4915 {
4916 unsigned long symnum;
4917 Sym_Match_Result matchres;
4918
4919 matchres.sym_out = NULL;
4920 matchres.vsymp = NULL;
4921 matchres.vcount = 0;
4922
4923 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4924 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4925 if (symnum >= obj->nchains)
4926 return (ESRCH); /* Bad object */
4927
4928 if (matched_symbol(req, obj, &matchres, symnum)) {
4929 req->sym_out = matchres.sym_out;
4930 req->defobj_out = obj;
4931 return (0);
4932 }
4933 }
4934 if (matchres.vcount == 1) {
4935 req->sym_out = matchres.vsymp;
4936 req->defobj_out = obj;
4937 return (0);
4938 }
4939 return (ESRCH);
4940 }
4941
4942 /* Search for symbol using GNU hash function */
4943 static int
symlook_obj1_gnu(SymLook * req,const Obj_Entry * obj)4944 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4945 {
4946 Elf_Addr bloom_word;
4947 const Elf32_Word *hashval;
4948 Elf32_Word bucket;
4949 Sym_Match_Result matchres;
4950 unsigned int h1, h2;
4951 unsigned long symnum;
4952
4953 matchres.sym_out = NULL;
4954 matchres.vsymp = NULL;
4955 matchres.vcount = 0;
4956
4957 /* Pick right bitmask word from Bloom filter array */
4958 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4959 obj->maskwords_bm_gnu];
4960
4961 /* Calculate modulus word size of gnu hash and its derivative */
4962 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4963 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4964
4965 /* Filter out the "definitely not in set" queries */
4966 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4967 return (ESRCH);
4968
4969 /* Locate hash chain and corresponding value element*/
4970 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4971 if (bucket == 0)
4972 return (ESRCH);
4973 hashval = &obj->chain_zero_gnu[bucket];
4974 do {
4975 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4976 symnum = hashval - obj->chain_zero_gnu;
4977 if (matched_symbol(req, obj, &matchres, symnum)) {
4978 req->sym_out = matchres.sym_out;
4979 req->defobj_out = obj;
4980 return (0);
4981 }
4982 }
4983 } while ((*hashval++ & 1) == 0);
4984 if (matchres.vcount == 1) {
4985 req->sym_out = matchres.vsymp;
4986 req->defobj_out = obj;
4987 return (0);
4988 }
4989 return (ESRCH);
4990 }
4991
4992 static void
trace_calc_fmts(const char ** main_local,const char ** fmt1,const char ** fmt2)4993 trace_calc_fmts(const char **main_local, const char **fmt1, const char **fmt2)
4994 {
4995 *main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME);
4996 if (*main_local == NULL)
4997 *main_local = "";
4998
4999 *fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1);
5000 if (*fmt1 == NULL)
5001 *fmt1 = "\t%o => %p (%x)\n";
5002
5003 *fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2);
5004 if (*fmt2 == NULL)
5005 *fmt2 = "\t%o (%x)\n";
5006 }
5007
5008 static void
trace_print_obj(Obj_Entry * obj,const char * name,const char * path,const char * main_local,const char * fmt1,const char * fmt2)5009 trace_print_obj(Obj_Entry *obj, const char *name, const char *path,
5010 const char *main_local, const char *fmt1, const char *fmt2)
5011 {
5012 const char *fmt;
5013 int c;
5014
5015 if (fmt1 == NULL)
5016 fmt = fmt2;
5017 else
5018 /* XXX bogus */
5019 fmt = strncmp(name, "lib", 3) == 0 ? fmt1 : fmt2;
5020
5021 while ((c = *fmt++) != '\0') {
5022 switch (c) {
5023 default:
5024 rtld_putchar(c);
5025 continue;
5026 case '\\':
5027 switch (c = *fmt) {
5028 case '\0':
5029 continue;
5030 case 'n':
5031 rtld_putchar('\n');
5032 break;
5033 case 't':
5034 rtld_putchar('\t');
5035 break;
5036 }
5037 break;
5038 case '%':
5039 switch (c = *fmt) {
5040 case '\0':
5041 continue;
5042 case '%':
5043 default:
5044 rtld_putchar(c);
5045 break;
5046 case 'A':
5047 rtld_putstr(main_local);
5048 break;
5049 case 'a':
5050 rtld_putstr(obj_main->path);
5051 break;
5052 case 'o':
5053 rtld_putstr(name);
5054 break;
5055 case 'p':
5056 rtld_putstr(path);
5057 break;
5058 case 'x':
5059 rtld_printf("%p", obj != NULL ?
5060 obj->mapbase : NULL);
5061 break;
5062 }
5063 break;
5064 }
5065 ++fmt;
5066 }
5067 }
5068
5069 static void
trace_loaded_objects(Obj_Entry * obj,bool show_preload)5070 trace_loaded_objects(Obj_Entry *obj, bool show_preload)
5071 {
5072 const char *fmt1, *fmt2, *main_local;
5073 const char *name, *path;
5074 bool first_spurious, list_containers;
5075
5076 trace_calc_fmts(&main_local, &fmt1, &fmt2);
5077 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL) != NULL;
5078
5079 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
5080 Needed_Entry *needed;
5081
5082 if (obj->marker)
5083 continue;
5084 if (list_containers && obj->needed != NULL)
5085 rtld_printf("%s:\n", obj->path);
5086 for (needed = obj->needed; needed; needed = needed->next) {
5087 if (needed->obj != NULL) {
5088 if (needed->obj->traced && !list_containers)
5089 continue;
5090 needed->obj->traced = true;
5091 path = needed->obj->path;
5092 } else
5093 path = "not found";
5094
5095 name = obj->strtab + needed->name;
5096 trace_print_obj(needed->obj, name, path, main_local,
5097 fmt1, fmt2);
5098 }
5099 }
5100
5101 if (show_preload) {
5102 if (ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2) == NULL)
5103 fmt2 = "\t%p (%x)\n";
5104 first_spurious = true;
5105
5106 TAILQ_FOREACH(obj, &obj_list, next) {
5107 if (obj->marker || obj == obj_main || obj->traced)
5108 continue;
5109
5110 if (list_containers && first_spurious) {
5111 rtld_printf("[preloaded]\n");
5112 first_spurious = false;
5113 }
5114
5115 Name_Entry *fname = STAILQ_FIRST(&obj->names);
5116 name = fname == NULL ? "<unknown>" : fname->name;
5117 trace_print_obj(obj, name, obj->path, main_local,
5118 NULL, fmt2);
5119 }
5120 }
5121 }
5122
5123 /*
5124 * Unload a dlopened object and its dependencies from memory and from
5125 * our data structures. It is assumed that the DAG rooted in the
5126 * object has already been unreferenced, and that the object has a
5127 * reference count of 0.
5128 */
5129 static void
unload_object(Obj_Entry * root,RtldLockState * lockstate)5130 unload_object(Obj_Entry *root, RtldLockState *lockstate)
5131 {
5132 Obj_Entry marker, *obj, *next;
5133
5134 assert(root->refcount == 0);
5135
5136 /*
5137 * Pass over the DAG removing unreferenced objects from
5138 * appropriate lists.
5139 */
5140 unlink_object(root);
5141
5142 /* Unmap all objects that are no longer referenced. */
5143 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
5144 next = TAILQ_NEXT(obj, next);
5145 if (obj->marker || obj->refcount != 0)
5146 continue;
5147 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
5148 obj->mapsize, 0, obj->path);
5149 dbg("unloading \"%s\"", obj->path);
5150 /*
5151 * Unlink the object now to prevent new references from
5152 * being acquired while the bind lock is dropped in
5153 * recursive dlclose() invocations.
5154 */
5155 TAILQ_REMOVE(&obj_list, obj, next);
5156 obj_count--;
5157
5158 if (obj->filtees_loaded) {
5159 if (next != NULL) {
5160 init_marker(&marker);
5161 TAILQ_INSERT_BEFORE(next, &marker, next);
5162 unload_filtees(obj, lockstate);
5163 next = TAILQ_NEXT(&marker, next);
5164 TAILQ_REMOVE(&obj_list, &marker, next);
5165 } else
5166 unload_filtees(obj, lockstate);
5167 }
5168 release_object(obj);
5169 }
5170 }
5171
5172 static void
unlink_object(Obj_Entry * root)5173 unlink_object(Obj_Entry *root)
5174 {
5175 Objlist_Entry *elm;
5176
5177 if (root->refcount == 0) {
5178 /* Remove the object from the RTLD_GLOBAL list. */
5179 objlist_remove(&list_global, root);
5180
5181 /* Remove the object from all objects' DAG lists. */
5182 STAILQ_FOREACH(elm, &root->dagmembers, link) {
5183 objlist_remove(&elm->obj->dldags, root);
5184 if (elm->obj != root)
5185 unlink_object(elm->obj);
5186 }
5187 }
5188 }
5189
5190 static void
ref_dag(Obj_Entry * root)5191 ref_dag(Obj_Entry *root)
5192 {
5193 Objlist_Entry *elm;
5194
5195 assert(root->dag_inited);
5196 STAILQ_FOREACH(elm, &root->dagmembers, link)
5197 elm->obj->refcount++;
5198 }
5199
5200 static void
unref_dag(Obj_Entry * root)5201 unref_dag(Obj_Entry *root)
5202 {
5203 Objlist_Entry *elm;
5204
5205 assert(root->dag_inited);
5206 STAILQ_FOREACH(elm, &root->dagmembers, link)
5207 elm->obj->refcount--;
5208 }
5209
5210 /*
5211 * Common code for MD __tls_get_addr().
5212 */
5213 static void *
tls_get_addr_slow(Elf_Addr ** dtvp,int index,size_t offset,bool locked)5214 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset, bool locked)
5215 {
5216 Elf_Addr *newdtv, *dtv;
5217 RtldLockState lockstate;
5218 int to_copy;
5219
5220 dtv = *dtvp;
5221 /* Check dtv generation in case new modules have arrived */
5222 if (dtv[0] != tls_dtv_generation) {
5223 if (!locked)
5224 wlock_acquire(rtld_bind_lock, &lockstate);
5225 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
5226 to_copy = dtv[1];
5227 if (to_copy > tls_max_index)
5228 to_copy = tls_max_index;
5229 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
5230 newdtv[0] = tls_dtv_generation;
5231 newdtv[1] = tls_max_index;
5232 free(dtv);
5233 if (!locked)
5234 lock_release(rtld_bind_lock, &lockstate);
5235 dtv = *dtvp = newdtv;
5236 }
5237
5238 /* Dynamically allocate module TLS if necessary */
5239 if (dtv[index + 1] == 0) {
5240 /* Signal safe, wlock will block out signals. */
5241 if (!locked)
5242 wlock_acquire(rtld_bind_lock, &lockstate);
5243 if (!dtv[index + 1])
5244 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
5245 if (!locked)
5246 lock_release(rtld_bind_lock, &lockstate);
5247 }
5248 return ((void *)(dtv[index + 1] + offset));
5249 }
5250
5251 void *
tls_get_addr_common(uintptr_t ** dtvp,int index,size_t offset)5252 tls_get_addr_common(uintptr_t **dtvp, int index, size_t offset)
5253 {
5254 uintptr_t *dtv;
5255
5256 dtv = *dtvp;
5257 /* Check dtv generation in case new modules have arrived */
5258 if (__predict_true(dtv[0] == tls_dtv_generation &&
5259 dtv[index + 1] != 0))
5260 return ((void *)(dtv[index + 1] + offset));
5261 return (tls_get_addr_slow(dtvp, index, offset, false));
5262 }
5263
5264 #ifdef TLS_VARIANT_I
5265
5266 /*
5267 * Return pointer to allocated TLS block
5268 */
5269 static void *
get_tls_block_ptr(void * tcb,size_t tcbsize)5270 get_tls_block_ptr(void *tcb, size_t tcbsize)
5271 {
5272 size_t extra_size, post_size, pre_size, tls_block_size;
5273 size_t tls_init_align;
5274
5275 tls_init_align = MAX(obj_main->tlsalign, 1);
5276
5277 /* Compute fragments sizes. */
5278 extra_size = tcbsize - TLS_TCB_SIZE;
5279 post_size = calculate_tls_post_size(tls_init_align);
5280 tls_block_size = tcbsize + post_size;
5281 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
5282
5283 return ((char *)tcb - pre_size - extra_size);
5284 }
5285
5286 /*
5287 * Allocate Static TLS using the Variant I method.
5288 *
5289 * For details on the layout, see lib/libc/gen/tls.c.
5290 *
5291 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as
5292 * it is based on tls_last_offset, and TLS offsets here are really TCB
5293 * offsets, whereas libc's tls_static_space is just the executable's static
5294 * TLS segment.
5295 */
5296 void *
allocate_tls(Obj_Entry * objs,void * oldtcb,size_t tcbsize,size_t tcbalign)5297 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
5298 {
5299 Obj_Entry *obj;
5300 char *tls_block;
5301 Elf_Addr *dtv, **tcb;
5302 Elf_Addr addr;
5303 Elf_Addr i;
5304 size_t extra_size, maxalign, post_size, pre_size, tls_block_size;
5305 size_t tls_init_align, tls_init_offset;
5306
5307 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
5308 return (oldtcb);
5309
5310 assert(tcbsize >= TLS_TCB_SIZE);
5311 maxalign = MAX(tcbalign, tls_static_max_align);
5312 tls_init_align = MAX(obj_main->tlsalign, 1);
5313
5314 /* Compute fragmets sizes. */
5315 extra_size = tcbsize - TLS_TCB_SIZE;
5316 post_size = calculate_tls_post_size(tls_init_align);
5317 tls_block_size = tcbsize + post_size;
5318 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
5319 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size;
5320
5321 /* Allocate whole TLS block */
5322 tls_block = xmalloc_aligned(tls_block_size, maxalign, 0);
5323 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size);
5324
5325 if (oldtcb != NULL) {
5326 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize),
5327 tls_static_space);
5328 free(get_tls_block_ptr(oldtcb, tcbsize));
5329
5330 /* Adjust the DTV. */
5331 dtv = tcb[0];
5332 for (i = 0; i < dtv[1]; i++) {
5333 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
5334 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
5335 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb;
5336 }
5337 }
5338 } else {
5339 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
5340 tcb[0] = dtv;
5341 dtv[0] = tls_dtv_generation;
5342 dtv[1] = tls_max_index;
5343
5344 for (obj = globallist_curr(objs); obj != NULL;
5345 obj = globallist_next(obj)) {
5346 if (obj->tlsoffset == 0)
5347 continue;
5348 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1);
5349 addr = (Elf_Addr)tcb + obj->tlsoffset;
5350 if (tls_init_offset > 0)
5351 memset((void *)addr, 0, tls_init_offset);
5352 if (obj->tlsinitsize > 0) {
5353 memcpy((void *)(addr + tls_init_offset), obj->tlsinit,
5354 obj->tlsinitsize);
5355 }
5356 if (obj->tlssize > obj->tlsinitsize) {
5357 memset((void *)(addr + tls_init_offset + obj->tlsinitsize),
5358 0, obj->tlssize - obj->tlsinitsize - tls_init_offset);
5359 }
5360 dtv[obj->tlsindex + 1] = addr;
5361 }
5362 }
5363
5364 return (tcb);
5365 }
5366
5367 void
free_tls(void * tcb,size_t tcbsize,size_t tcbalign __unused)5368 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
5369 {
5370 Elf_Addr *dtv;
5371 Elf_Addr tlsstart, tlsend;
5372 size_t post_size;
5373 size_t dtvsize, i, tls_init_align __unused;
5374
5375 assert(tcbsize >= TLS_TCB_SIZE);
5376 tls_init_align = MAX(obj_main->tlsalign, 1);
5377
5378 /* Compute fragments sizes. */
5379 post_size = calculate_tls_post_size(tls_init_align);
5380
5381 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size;
5382 tlsend = (Elf_Addr)tcb + tls_static_space;
5383
5384 dtv = *(Elf_Addr **)tcb;
5385 dtvsize = dtv[1];
5386 for (i = 0; i < dtvsize; i++) {
5387 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
5388 free((void*)dtv[i+2]);
5389 }
5390 }
5391 free(dtv);
5392 free(get_tls_block_ptr(tcb, tcbsize));
5393 }
5394
5395 #endif /* TLS_VARIANT_I */
5396
5397 #ifdef TLS_VARIANT_II
5398
5399 /*
5400 * Allocate Static TLS using the Variant II method.
5401 */
5402 void *
allocate_tls(Obj_Entry * objs,void * oldtls,size_t tcbsize,size_t tcbalign)5403 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
5404 {
5405 Obj_Entry *obj;
5406 size_t size, ralign;
5407 char *tls;
5408 Elf_Addr *dtv, *olddtv;
5409 Elf_Addr segbase, oldsegbase, addr;
5410 size_t i;
5411
5412 ralign = tcbalign;
5413 if (tls_static_max_align > ralign)
5414 ralign = tls_static_max_align;
5415 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign);
5416
5417 assert(tcbsize >= 2*sizeof(Elf_Addr));
5418 tls = xmalloc_aligned(size, ralign, 0 /* XXX */);
5419 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
5420
5421 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign));
5422 ((Elf_Addr *)segbase)[0] = segbase;
5423 ((Elf_Addr *)segbase)[1] = (Elf_Addr) dtv;
5424
5425 dtv[0] = tls_dtv_generation;
5426 dtv[1] = tls_max_index;
5427
5428 if (oldtls) {
5429 /*
5430 * Copy the static TLS block over whole.
5431 */
5432 oldsegbase = (Elf_Addr) oldtls;
5433 memcpy((void *)(segbase - tls_static_space),
5434 (const void *)(oldsegbase - tls_static_space),
5435 tls_static_space);
5436
5437 /*
5438 * If any dynamic TLS blocks have been created tls_get_addr(),
5439 * move them over.
5440 */
5441 olddtv = ((Elf_Addr **)oldsegbase)[1];
5442 for (i = 0; i < olddtv[1]; i++) {
5443 if (olddtv[i + 2] < oldsegbase - size ||
5444 olddtv[i + 2] > oldsegbase) {
5445 dtv[i + 2] = olddtv[i + 2];
5446 olddtv[i + 2] = 0;
5447 }
5448 }
5449
5450 /*
5451 * We assume that this block was the one we created with
5452 * allocate_initial_tls().
5453 */
5454 free_tls(oldtls, 2 * sizeof(Elf_Addr), sizeof(Elf_Addr));
5455 } else {
5456 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
5457 if (obj->marker || obj->tlsoffset == 0)
5458 continue;
5459 addr = segbase - obj->tlsoffset;
5460 memset((void *)(addr + obj->tlsinitsize),
5461 0, obj->tlssize - obj->tlsinitsize);
5462 if (obj->tlsinit) {
5463 memcpy((void *)addr, obj->tlsinit, obj->tlsinitsize);
5464 obj->static_tls_copied = true;
5465 }
5466 dtv[obj->tlsindex + 1] = addr;
5467 }
5468 }
5469
5470 return ((void *)segbase);
5471 }
5472
5473 void
free_tls(void * tls,size_t tcbsize __unused,size_t tcbalign)5474 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign)
5475 {
5476 Elf_Addr* dtv;
5477 size_t size, ralign;
5478 int dtvsize, i;
5479 Elf_Addr tlsstart, tlsend;
5480
5481 /*
5482 * Figure out the size of the initial TLS block so that we can
5483 * find stuff which ___tls_get_addr() allocated dynamically.
5484 */
5485 ralign = tcbalign;
5486 if (tls_static_max_align > ralign)
5487 ralign = tls_static_max_align;
5488 size = roundup(tls_static_space, ralign);
5489
5490 dtv = ((Elf_Addr **)tls)[1];
5491 dtvsize = dtv[1];
5492 tlsend = (Elf_Addr)tls;
5493 tlsstart = tlsend - size;
5494 for (i = 0; i < dtvsize; i++) {
5495 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart ||
5496 dtv[i + 2] > tlsend)) {
5497 free((void *)dtv[i + 2]);
5498 }
5499 }
5500
5501 free((void *)tlsstart);
5502 free((void *)dtv);
5503 }
5504
5505 #endif /* TLS_VARIANT_II */
5506
5507 /*
5508 * Allocate TLS block for module with given index.
5509 */
5510 void *
allocate_module_tls(int index)5511 allocate_module_tls(int index)
5512 {
5513 Obj_Entry *obj;
5514 char *p;
5515
5516 TAILQ_FOREACH(obj, &obj_list, next) {
5517 if (obj->marker)
5518 continue;
5519 if (obj->tlsindex == index)
5520 break;
5521 }
5522 if (obj == NULL) {
5523 _rtld_error("Can't find module with TLS index %d", index);
5524 rtld_die();
5525 }
5526
5527 if (obj->tls_static) {
5528 #ifdef TLS_VARIANT_I
5529 p = (char *)_tcb_get() + obj->tlsoffset + TLS_TCB_SIZE;
5530 #else
5531 p = (char *)_tcb_get() - obj->tlsoffset;
5532 #endif
5533 return (p);
5534 }
5535
5536 obj->tls_dynamic = true;
5537
5538 p = xmalloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset);
5539 memcpy(p, obj->tlsinit, obj->tlsinitsize);
5540 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
5541 return (p);
5542 }
5543
5544 bool
allocate_tls_offset(Obj_Entry * obj)5545 allocate_tls_offset(Obj_Entry *obj)
5546 {
5547 size_t off;
5548
5549 if (obj->tls_dynamic)
5550 return (false);
5551
5552 if (obj->tls_static)
5553 return (true);
5554
5555 if (obj->tlssize == 0) {
5556 obj->tls_static = true;
5557 return (true);
5558 }
5559
5560 if (tls_last_offset == 0)
5561 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign,
5562 obj->tlspoffset);
5563 else
5564 off = calculate_tls_offset(tls_last_offset, tls_last_size,
5565 obj->tlssize, obj->tlsalign, obj->tlspoffset);
5566
5567 obj->tlsoffset = off;
5568 #ifdef TLS_VARIANT_I
5569 off += obj->tlssize;
5570 #endif
5571
5572 /*
5573 * If we have already fixed the size of the static TLS block, we
5574 * must stay within that size. When allocating the static TLS, we
5575 * leave a small amount of space spare to be used for dynamically
5576 * loading modules which use static TLS.
5577 */
5578 if (tls_static_space != 0) {
5579 if (off > tls_static_space)
5580 return (false);
5581 } else if (obj->tlsalign > tls_static_max_align) {
5582 tls_static_max_align = obj->tlsalign;
5583 }
5584
5585 tls_last_offset = off;
5586 tls_last_size = obj->tlssize;
5587 obj->tls_static = true;
5588
5589 return (true);
5590 }
5591
5592 void
free_tls_offset(Obj_Entry * obj)5593 free_tls_offset(Obj_Entry *obj)
5594 {
5595
5596 /*
5597 * If we were the last thing to allocate out of the static TLS
5598 * block, we give our space back to the 'allocator'. This is a
5599 * simplistic workaround to allow libGL.so.1 to be loaded and
5600 * unloaded multiple times.
5601 */
5602 size_t off = obj->tlsoffset;
5603 #ifdef TLS_VARIANT_I
5604 off += obj->tlssize;
5605 #endif
5606 if (off == tls_last_offset) {
5607 tls_last_offset -= obj->tlssize;
5608 tls_last_size = 0;
5609 }
5610 }
5611
5612 void *
_rtld_allocate_tls(void * oldtls,size_t tcbsize,size_t tcbalign)5613 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
5614 {
5615 void *ret;
5616 RtldLockState lockstate;
5617
5618 wlock_acquire(rtld_bind_lock, &lockstate);
5619 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
5620 tcbsize, tcbalign);
5621 lock_release(rtld_bind_lock, &lockstate);
5622 return (ret);
5623 }
5624
5625 void
_rtld_free_tls(void * tcb,size_t tcbsize,size_t tcbalign)5626 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
5627 {
5628 RtldLockState lockstate;
5629
5630 wlock_acquire(rtld_bind_lock, &lockstate);
5631 free_tls(tcb, tcbsize, tcbalign);
5632 lock_release(rtld_bind_lock, &lockstate);
5633 }
5634
5635 static void
object_add_name(Obj_Entry * obj,const char * name)5636 object_add_name(Obj_Entry *obj, const char *name)
5637 {
5638 Name_Entry *entry;
5639 size_t len;
5640
5641 len = strlen(name);
5642 entry = malloc(sizeof(Name_Entry) + len);
5643
5644 if (entry != NULL) {
5645 strcpy(entry->name, name);
5646 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5647 }
5648 }
5649
5650 static int
object_match_name(const Obj_Entry * obj,const char * name)5651 object_match_name(const Obj_Entry *obj, const char *name)
5652 {
5653 Name_Entry *entry;
5654
5655 STAILQ_FOREACH(entry, &obj->names, link) {
5656 if (strcmp(name, entry->name) == 0)
5657 return (1);
5658 }
5659 return (0);
5660 }
5661
5662 static Obj_Entry *
locate_dependency(const Obj_Entry * obj,const char * name)5663 locate_dependency(const Obj_Entry *obj, const char *name)
5664 {
5665 const Objlist_Entry *entry;
5666 const Needed_Entry *needed;
5667
5668 STAILQ_FOREACH(entry, &list_main, link) {
5669 if (object_match_name(entry->obj, name))
5670 return (entry->obj);
5671 }
5672
5673 for (needed = obj->needed; needed != NULL; needed = needed->next) {
5674 if (strcmp(obj->strtab + needed->name, name) == 0 ||
5675 (needed->obj != NULL && object_match_name(needed->obj, name))) {
5676 /*
5677 * If there is DT_NEEDED for the name we are looking for,
5678 * we are all set. Note that object might not be found if
5679 * dependency was not loaded yet, so the function can
5680 * return NULL here. This is expected and handled
5681 * properly by the caller.
5682 */
5683 return (needed->obj);
5684 }
5685 }
5686 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
5687 obj->path, name);
5688 rtld_die();
5689 }
5690
5691 static int
check_object_provided_version(Obj_Entry * refobj,const Obj_Entry * depobj,const Elf_Vernaux * vna)5692 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
5693 const Elf_Vernaux *vna)
5694 {
5695 const Elf_Verdef *vd;
5696 const char *vername;
5697
5698 vername = refobj->strtab + vna->vna_name;
5699 vd = depobj->verdef;
5700 if (vd == NULL) {
5701 _rtld_error("%s: version %s required by %s not defined",
5702 depobj->path, vername, refobj->path);
5703 return (-1);
5704 }
5705 for (;;) {
5706 if (vd->vd_version != VER_DEF_CURRENT) {
5707 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5708 depobj->path, vd->vd_version);
5709 return (-1);
5710 }
5711 if (vna->vna_hash == vd->vd_hash) {
5712 const Elf_Verdaux *aux = (const Elf_Verdaux *)
5713 ((const char *)vd + vd->vd_aux);
5714 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
5715 return (0);
5716 }
5717 if (vd->vd_next == 0)
5718 break;
5719 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5720 }
5721 if (vna->vna_flags & VER_FLG_WEAK)
5722 return (0);
5723 _rtld_error("%s: version %s required by %s not found",
5724 depobj->path, vername, refobj->path);
5725 return (-1);
5726 }
5727
5728 static int
rtld_verify_object_versions(Obj_Entry * obj)5729 rtld_verify_object_versions(Obj_Entry *obj)
5730 {
5731 const Elf_Verneed *vn;
5732 const Elf_Verdef *vd;
5733 const Elf_Verdaux *vda;
5734 const Elf_Vernaux *vna;
5735 const Obj_Entry *depobj;
5736 int maxvernum, vernum;
5737
5738 if (obj->ver_checked)
5739 return (0);
5740 obj->ver_checked = true;
5741
5742 maxvernum = 0;
5743 /*
5744 * Walk over defined and required version records and figure out
5745 * max index used by any of them. Do very basic sanity checking
5746 * while there.
5747 */
5748 vn = obj->verneed;
5749 while (vn != NULL) {
5750 if (vn->vn_version != VER_NEED_CURRENT) {
5751 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
5752 obj->path, vn->vn_version);
5753 return (-1);
5754 }
5755 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5756 for (;;) {
5757 vernum = VER_NEED_IDX(vna->vna_other);
5758 if (vernum > maxvernum)
5759 maxvernum = vernum;
5760 if (vna->vna_next == 0)
5761 break;
5762 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5763 }
5764 if (vn->vn_next == 0)
5765 break;
5766 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5767 }
5768
5769 vd = obj->verdef;
5770 while (vd != NULL) {
5771 if (vd->vd_version != VER_DEF_CURRENT) {
5772 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5773 obj->path, vd->vd_version);
5774 return (-1);
5775 }
5776 vernum = VER_DEF_IDX(vd->vd_ndx);
5777 if (vernum > maxvernum)
5778 maxvernum = vernum;
5779 if (vd->vd_next == 0)
5780 break;
5781 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5782 }
5783
5784 if (maxvernum == 0)
5785 return (0);
5786
5787 /*
5788 * Store version information in array indexable by version index.
5789 * Verify that object version requirements are satisfied along the
5790 * way.
5791 */
5792 obj->vernum = maxvernum + 1;
5793 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
5794
5795 vd = obj->verdef;
5796 while (vd != NULL) {
5797 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
5798 vernum = VER_DEF_IDX(vd->vd_ndx);
5799 assert(vernum <= maxvernum);
5800 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux);
5801 obj->vertab[vernum].hash = vd->vd_hash;
5802 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
5803 obj->vertab[vernum].file = NULL;
5804 obj->vertab[vernum].flags = 0;
5805 }
5806 if (vd->vd_next == 0)
5807 break;
5808 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5809 }
5810
5811 vn = obj->verneed;
5812 while (vn != NULL) {
5813 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
5814 if (depobj == NULL)
5815 return (-1);
5816 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5817 for (;;) {
5818 if (check_object_provided_version(obj, depobj, vna))
5819 return (-1);
5820 vernum = VER_NEED_IDX(vna->vna_other);
5821 assert(vernum <= maxvernum);
5822 obj->vertab[vernum].hash = vna->vna_hash;
5823 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
5824 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
5825 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
5826 VER_INFO_HIDDEN : 0;
5827 if (vna->vna_next == 0)
5828 break;
5829 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5830 }
5831 if (vn->vn_next == 0)
5832 break;
5833 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5834 }
5835 return (0);
5836 }
5837
5838 static int
rtld_verify_versions(const Objlist * objlist)5839 rtld_verify_versions(const Objlist *objlist)
5840 {
5841 Objlist_Entry *entry;
5842 int rc;
5843
5844 rc = 0;
5845 STAILQ_FOREACH(entry, objlist, link) {
5846 /*
5847 * Skip dummy objects or objects that have their version requirements
5848 * already checked.
5849 */
5850 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
5851 continue;
5852 if (rtld_verify_object_versions(entry->obj) == -1) {
5853 rc = -1;
5854 if (ld_tracing == NULL)
5855 break;
5856 }
5857 }
5858 if (rc == 0 || ld_tracing != NULL)
5859 rc = rtld_verify_object_versions(&obj_rtld);
5860 return (rc);
5861 }
5862
5863 const Ver_Entry *
fetch_ventry(const Obj_Entry * obj,unsigned long symnum)5864 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
5865 {
5866 Elf_Versym vernum;
5867
5868 if (obj->vertab) {
5869 vernum = VER_NDX(obj->versyms[symnum]);
5870 if (vernum >= obj->vernum) {
5871 _rtld_error("%s: symbol %s has wrong verneed value %d",
5872 obj->path, obj->strtab + symnum, vernum);
5873 } else if (obj->vertab[vernum].hash != 0) {
5874 return (&obj->vertab[vernum]);
5875 }
5876 }
5877 return (NULL);
5878 }
5879
5880 int
_rtld_get_stack_prot(void)5881 _rtld_get_stack_prot(void)
5882 {
5883
5884 return (stack_prot);
5885 }
5886
5887 int
_rtld_is_dlopened(void * arg)5888 _rtld_is_dlopened(void *arg)
5889 {
5890 Obj_Entry *obj;
5891 RtldLockState lockstate;
5892 int res;
5893
5894 rlock_acquire(rtld_bind_lock, &lockstate);
5895 obj = dlcheck(arg);
5896 if (obj == NULL)
5897 obj = obj_from_addr(arg);
5898 if (obj == NULL) {
5899 _rtld_error("No shared object contains address");
5900 lock_release(rtld_bind_lock, &lockstate);
5901 return (-1);
5902 }
5903 res = obj->dlopened ? 1 : 0;
5904 lock_release(rtld_bind_lock, &lockstate);
5905 return (res);
5906 }
5907
5908 static int
obj_remap_relro(Obj_Entry * obj,int prot)5909 obj_remap_relro(Obj_Entry *obj, int prot)
5910 {
5911
5912 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size,
5913 prot) == -1) {
5914 _rtld_error("%s: Cannot set relro protection to %#x: %s",
5915 obj->path, prot, rtld_strerror(errno));
5916 return (-1);
5917 }
5918 return (0);
5919 }
5920
5921 static int
obj_disable_relro(Obj_Entry * obj)5922 obj_disable_relro(Obj_Entry *obj)
5923 {
5924
5925 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE));
5926 }
5927
5928 static int
obj_enforce_relro(Obj_Entry * obj)5929 obj_enforce_relro(Obj_Entry *obj)
5930 {
5931
5932 return (obj_remap_relro(obj, PROT_READ));
5933 }
5934
5935 static void
map_stacks_exec(RtldLockState * lockstate)5936 map_stacks_exec(RtldLockState *lockstate)
5937 {
5938 void (*thr_map_stacks_exec)(void);
5939
5940 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
5941 return;
5942 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
5943 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
5944 if (thr_map_stacks_exec != NULL) {
5945 stack_prot |= PROT_EXEC;
5946 thr_map_stacks_exec();
5947 }
5948 }
5949
5950 static void
distribute_static_tls(Objlist * list,RtldLockState * lockstate)5951 distribute_static_tls(Objlist *list, RtldLockState *lockstate)
5952 {
5953 Objlist_Entry *elm;
5954 Obj_Entry *obj;
5955 void (*distrib)(size_t, void *, size_t, size_t);
5956
5957 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t)
5958 get_program_var_addr("__pthread_distribute_static_tls", lockstate);
5959 if (distrib == NULL)
5960 return;
5961 STAILQ_FOREACH(elm, list, link) {
5962 obj = elm->obj;
5963 if (obj->marker || !obj->tls_static || obj->static_tls_copied)
5964 continue;
5965 lock_release(rtld_bind_lock, lockstate);
5966 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize,
5967 obj->tlssize);
5968 wlock_acquire(rtld_bind_lock, lockstate);
5969 obj->static_tls_copied = true;
5970 }
5971 }
5972
5973 void
symlook_init(SymLook * dst,const char * name)5974 symlook_init(SymLook *dst, const char *name)
5975 {
5976
5977 bzero(dst, sizeof(*dst));
5978 dst->name = name;
5979 dst->hash = elf_hash(name);
5980 dst->hash_gnu = gnu_hash(name);
5981 }
5982
5983 static void
symlook_init_from_req(SymLook * dst,const SymLook * src)5984 symlook_init_from_req(SymLook *dst, const SymLook *src)
5985 {
5986
5987 dst->name = src->name;
5988 dst->hash = src->hash;
5989 dst->hash_gnu = src->hash_gnu;
5990 dst->ventry = src->ventry;
5991 dst->flags = src->flags;
5992 dst->defobj_out = NULL;
5993 dst->sym_out = NULL;
5994 dst->lockstate = src->lockstate;
5995 }
5996
5997 static int
open_binary_fd(const char * argv0,bool search_in_path,const char ** binpath_res)5998 open_binary_fd(const char *argv0, bool search_in_path,
5999 const char **binpath_res)
6000 {
6001 char *binpath, *pathenv, *pe, *res1;
6002 const char *res;
6003 int fd;
6004
6005 binpath = NULL;
6006 res = NULL;
6007 if (search_in_path && strchr(argv0, '/') == NULL) {
6008 binpath = xmalloc(PATH_MAX);
6009 pathenv = getenv("PATH");
6010 if (pathenv == NULL) {
6011 _rtld_error("-p and no PATH environment variable");
6012 rtld_die();
6013 }
6014 pathenv = strdup(pathenv);
6015 if (pathenv == NULL) {
6016 _rtld_error("Cannot allocate memory");
6017 rtld_die();
6018 }
6019 fd = -1;
6020 errno = ENOENT;
6021 while ((pe = strsep(&pathenv, ":")) != NULL) {
6022 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX)
6023 continue;
6024 if (binpath[0] != '\0' &&
6025 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX)
6026 continue;
6027 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX)
6028 continue;
6029 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
6030 if (fd != -1 || errno != ENOENT) {
6031 res = binpath;
6032 break;
6033 }
6034 }
6035 free(pathenv);
6036 } else {
6037 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
6038 res = argv0;
6039 }
6040
6041 if (fd == -1) {
6042 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno));
6043 rtld_die();
6044 }
6045 if (res != NULL && res[0] != '/') {
6046 res1 = xmalloc(PATH_MAX);
6047 if (realpath(res, res1) != NULL) {
6048 if (res != argv0)
6049 free(__DECONST(char *, res));
6050 res = res1;
6051 } else {
6052 free(res1);
6053 }
6054 }
6055 *binpath_res = res;
6056 return (fd);
6057 }
6058
6059 /*
6060 * Parse a set of command-line arguments.
6061 */
6062 static int
parse_args(char * argv[],int argc,bool * use_pathp,int * fdp,const char ** argv0,bool * dir_ignore)6063 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp,
6064 const char **argv0, bool *dir_ignore)
6065 {
6066 const char *arg;
6067 char machine[64];
6068 size_t sz;
6069 int arglen, fd, i, j, mib[2];
6070 char opt;
6071 bool seen_b, seen_f;
6072
6073 dbg("Parsing command-line arguments");
6074 *use_pathp = false;
6075 *fdp = -1;
6076 *dir_ignore = false;
6077 seen_b = seen_f = false;
6078
6079 for (i = 1; i < argc; i++ ) {
6080 arg = argv[i];
6081 dbg("argv[%d]: '%s'", i, arg);
6082
6083 /*
6084 * rtld arguments end with an explicit "--" or with the first
6085 * non-prefixed argument.
6086 */
6087 if (strcmp(arg, "--") == 0) {
6088 i++;
6089 break;
6090 }
6091 if (arg[0] != '-')
6092 break;
6093
6094 /*
6095 * All other arguments are single-character options that can
6096 * be combined, so we need to search through `arg` for them.
6097 */
6098 arglen = strlen(arg);
6099 for (j = 1; j < arglen; j++) {
6100 opt = arg[j];
6101 if (opt == 'h') {
6102 print_usage(argv[0]);
6103 _exit(0);
6104 } else if (opt == 'b') {
6105 if (seen_f) {
6106 _rtld_error("Both -b and -f specified");
6107 rtld_die();
6108 }
6109 if (j != arglen - 1) {
6110 _rtld_error("Invalid options: %s", arg);
6111 rtld_die();
6112 }
6113 i++;
6114 *argv0 = argv[i];
6115 seen_b = true;
6116 break;
6117 } else if (opt == 'd') {
6118 *dir_ignore = true;
6119 } else if (opt == 'f') {
6120 if (seen_b) {
6121 _rtld_error("Both -b and -f specified");
6122 rtld_die();
6123 }
6124
6125 /*
6126 * -f XX can be used to specify a
6127 * descriptor for the binary named at
6128 * the command line (i.e., the later
6129 * argument will specify the process
6130 * name but the descriptor is what
6131 * will actually be executed).
6132 *
6133 * -f must be the last option in the
6134 * group, e.g., -abcf <fd>.
6135 */
6136 if (j != arglen - 1) {
6137 _rtld_error("Invalid options: %s", arg);
6138 rtld_die();
6139 }
6140 i++;
6141 fd = parse_integer(argv[i]);
6142 if (fd == -1) {
6143 _rtld_error(
6144 "Invalid file descriptor: '%s'",
6145 argv[i]);
6146 rtld_die();
6147 }
6148 *fdp = fd;
6149 seen_f = true;
6150 break;
6151 } else if (opt == 'o') {
6152 struct ld_env_var_desc *l;
6153 char *n, *v;
6154 u_int ll;
6155
6156 if (j != arglen - 1) {
6157 _rtld_error("Invalid options: %s", arg);
6158 rtld_die();
6159 }
6160 i++;
6161 n = argv[i];
6162 v = strchr(n, '=');
6163 if (v == NULL) {
6164 _rtld_error("No '=' in -o parameter");
6165 rtld_die();
6166 }
6167 for (ll = 0; ll < nitems(ld_env_vars); ll++) {
6168 l = &ld_env_vars[ll];
6169 if (v - n == (ptrdiff_t)strlen(l->n) &&
6170 strncmp(n, l->n, v - n) == 0) {
6171 l->val = v + 1;
6172 break;
6173 }
6174 }
6175 if (ll == nitems(ld_env_vars)) {
6176 _rtld_error("Unknown LD_ option %s",
6177 n);
6178 rtld_die();
6179 }
6180 } else if (opt == 'p') {
6181 *use_pathp = true;
6182 } else if (opt == 'u') {
6183 u_int ll;
6184
6185 for (ll = 0; ll < nitems(ld_env_vars); ll++)
6186 ld_env_vars[ll].val = NULL;
6187 } else if (opt == 'v') {
6188 machine[0] = '\0';
6189 mib[0] = CTL_HW;
6190 mib[1] = HW_MACHINE;
6191 sz = sizeof(machine);
6192 sysctl(mib, nitems(mib), machine, &sz, NULL, 0);
6193 ld_elf_hints_path = ld_get_env_var(
6194 LD_ELF_HINTS_PATH);
6195 set_ld_elf_hints_path();
6196 rtld_printf(
6197 "FreeBSD ld-elf.so.1 %s\n"
6198 "FreeBSD_version %d\n"
6199 "Default lib path %s\n"
6200 "Hints lib path %s\n"
6201 "Env prefix %s\n"
6202 "Default hint file %s\n"
6203 "Hint file %s\n"
6204 "libmap file %s\n"
6205 "Optional static TLS size %zd bytes\n",
6206 machine,
6207 __FreeBSD_version, ld_standard_library_path,
6208 gethints(false),
6209 ld_env_prefix, ld_elf_hints_default,
6210 ld_elf_hints_path,
6211 ld_path_libmap_conf,
6212 ld_static_tls_extra);
6213 _exit(0);
6214 } else {
6215 _rtld_error("Invalid argument: '%s'", arg);
6216 print_usage(argv[0]);
6217 rtld_die();
6218 }
6219 }
6220 }
6221
6222 if (!seen_b)
6223 *argv0 = argv[i];
6224 return (i);
6225 }
6226
6227 /*
6228 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
6229 */
6230 static int
parse_integer(const char * str)6231 parse_integer(const char *str)
6232 {
6233 static const int RADIX = 10; /* XXXJA: possibly support hex? */
6234 const char *orig;
6235 int n;
6236 char c;
6237
6238 orig = str;
6239 n = 0;
6240 for (c = *str; c != '\0'; c = *++str) {
6241 if (c < '0' || c > '9')
6242 return (-1);
6243
6244 n *= RADIX;
6245 n += c - '0';
6246 }
6247
6248 /* Make sure we actually parsed something. */
6249 if (str == orig)
6250 return (-1);
6251 return (n);
6252 }
6253
6254 static void
print_usage(const char * argv0)6255 print_usage(const char *argv0)
6256 {
6257
6258 rtld_printf(
6259 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n"
6260 "\n"
6261 "Options:\n"
6262 " -h Display this help message\n"
6263 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n"
6264 " -d Ignore lack of exec permissions for the binary\n"
6265 " -f <FD> Execute <FD> instead of searching for <binary>\n"
6266 " -o <OPT>=<VAL> Set LD_<OPT> to <VAL>, without polluting env\n"
6267 " -p Search in PATH for named binary\n"
6268 " -u Ignore LD_ environment variables\n"
6269 " -v Display identification information\n"
6270 " -- End of RTLD options\n"
6271 " <binary> Name of process to execute\n"
6272 " <args> Arguments to the executed process\n", argv0);
6273 }
6274
6275 #define AUXFMT(at, xfmt) [at] = { .name = #at, .fmt = xfmt }
6276 static const struct auxfmt {
6277 const char *name;
6278 const char *fmt;
6279 } auxfmts[] = {
6280 AUXFMT(AT_NULL, NULL),
6281 AUXFMT(AT_IGNORE, NULL),
6282 AUXFMT(AT_EXECFD, "%ld"),
6283 AUXFMT(AT_PHDR, "%p"),
6284 AUXFMT(AT_PHENT, "%lu"),
6285 AUXFMT(AT_PHNUM, "%lu"),
6286 AUXFMT(AT_PAGESZ, "%lu"),
6287 AUXFMT(AT_BASE, "%#lx"),
6288 AUXFMT(AT_FLAGS, "%#lx"),
6289 AUXFMT(AT_ENTRY, "%p"),
6290 AUXFMT(AT_NOTELF, NULL),
6291 AUXFMT(AT_UID, "%ld"),
6292 AUXFMT(AT_EUID, "%ld"),
6293 AUXFMT(AT_GID, "%ld"),
6294 AUXFMT(AT_EGID, "%ld"),
6295 AUXFMT(AT_EXECPATH, "%s"),
6296 AUXFMT(AT_CANARY, "%p"),
6297 AUXFMT(AT_CANARYLEN, "%lu"),
6298 AUXFMT(AT_OSRELDATE, "%lu"),
6299 AUXFMT(AT_NCPUS, "%lu"),
6300 AUXFMT(AT_PAGESIZES, "%p"),
6301 AUXFMT(AT_PAGESIZESLEN, "%lu"),
6302 AUXFMT(AT_TIMEKEEP, "%p"),
6303 AUXFMT(AT_STACKPROT, "%#lx"),
6304 AUXFMT(AT_EHDRFLAGS, "%#lx"),
6305 AUXFMT(AT_HWCAP, "%#lx"),
6306 AUXFMT(AT_HWCAP2, "%#lx"),
6307 AUXFMT(AT_BSDFLAGS, "%#lx"),
6308 AUXFMT(AT_ARGC, "%lu"),
6309 AUXFMT(AT_ARGV, "%p"),
6310 AUXFMT(AT_ENVC, "%p"),
6311 AUXFMT(AT_ENVV, "%p"),
6312 AUXFMT(AT_PS_STRINGS, "%p"),
6313 AUXFMT(AT_FXRNG, "%p"),
6314 AUXFMT(AT_KPRELOAD, "%p"),
6315 AUXFMT(AT_USRSTACKBASE, "%#lx"),
6316 AUXFMT(AT_USRSTACKLIM, "%#lx"),
6317 };
6318
6319 static bool
is_ptr_fmt(const char * fmt)6320 is_ptr_fmt(const char *fmt)
6321 {
6322 char last;
6323
6324 last = fmt[strlen(fmt) - 1];
6325 return (last == 'p' || last == 's');
6326 }
6327
6328 static void
dump_auxv(Elf_Auxinfo ** aux_info)6329 dump_auxv(Elf_Auxinfo **aux_info)
6330 {
6331 Elf_Auxinfo *auxp;
6332 const struct auxfmt *fmt;
6333 int i;
6334
6335 for (i = 0; i < AT_COUNT; i++) {
6336 auxp = aux_info[i];
6337 if (auxp == NULL)
6338 continue;
6339 fmt = &auxfmts[i];
6340 if (fmt->fmt == NULL)
6341 continue;
6342 rtld_fdprintf(STDOUT_FILENO, "%s:\t", fmt->name);
6343 if (is_ptr_fmt(fmt->fmt)) {
6344 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt,
6345 auxp->a_un.a_ptr);
6346 } else {
6347 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt,
6348 auxp->a_un.a_val);
6349 }
6350 rtld_fdprintf(STDOUT_FILENO, "\n");
6351 }
6352 }
6353
6354 /*
6355 * Overrides for libc_pic-provided functions.
6356 */
6357
6358 int
__getosreldate(void)6359 __getosreldate(void)
6360 {
6361 size_t len;
6362 int oid[2];
6363 int error, osrel;
6364
6365 if (osreldate != 0)
6366 return (osreldate);
6367
6368 oid[0] = CTL_KERN;
6369 oid[1] = KERN_OSRELDATE;
6370 osrel = 0;
6371 len = sizeof(osrel);
6372 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
6373 if (error == 0 && osrel > 0 && len == sizeof(osrel))
6374 osreldate = osrel;
6375 return (osreldate);
6376 }
6377 const char *
rtld_strerror(int errnum)6378 rtld_strerror(int errnum)
6379 {
6380
6381 if (errnum < 0 || errnum >= sys_nerr)
6382 return ("Unknown error");
6383 return (sys_errlist[errnum]);
6384 }
6385
6386 char *
getenv(const char * name)6387 getenv(const char *name)
6388 {
6389 return (__DECONST(char *, rtld_get_env_val(environ, name,
6390 strlen(name))));
6391 }
6392
6393 /* malloc */
6394 void *
malloc(size_t nbytes)6395 malloc(size_t nbytes)
6396 {
6397
6398 return (__crt_malloc(nbytes));
6399 }
6400
6401 void *
calloc(size_t num,size_t size)6402 calloc(size_t num, size_t size)
6403 {
6404
6405 return (__crt_calloc(num, size));
6406 }
6407
6408 void
free(void * cp)6409 free(void *cp)
6410 {
6411
6412 __crt_free(cp);
6413 }
6414
6415 void *
realloc(void * cp,size_t nbytes)6416 realloc(void *cp, size_t nbytes)
6417 {
6418
6419 return (__crt_realloc(cp, nbytes));
6420 }
6421
6422 extern int _rtld_version__FreeBSD_version __exported;
6423 int _rtld_version__FreeBSD_version = __FreeBSD_version;
6424
6425 extern char _rtld_version_laddr_offset __exported;
6426 char _rtld_version_laddr_offset;
6427
6428 extern char _rtld_version_dlpi_tls_data __exported;
6429 char _rtld_version_dlpi_tls_data;
6430