1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2010 The FreeBSD Foundation
5 * All rights reserved.
6 *
7 * This software was developed by Rui Paulo under sponsorship from the
8 * FreeBSD Foundation.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include <sys/param.h>
33 #include <sys/sysctl.h>
34 #include <sys/user.h>
35
36 #include <assert.h>
37 #include <err.h>
38 #include <fcntl.h>
39 #include <limits.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <string.h>
43 #include <unistd.h>
44
45 #include <machine/elf.h>
46
47 #include <libelf.h>
48 #include <libproc.h>
49 #include <libprocstat.h>
50 #include <libutil.h>
51
52 #include "rtld_db.h"
53
54 static int _librtld_db_debug = 0;
55 #define DPRINTF(...) do { \
56 if (_librtld_db_debug) { \
57 fprintf(stderr, "librtld_db: DEBUG: "); \
58 fprintf(stderr, __VA_ARGS__); \
59 } \
60 } while (0)
61
62 void
rd_delete(rd_agent_t * rdap)63 rd_delete(rd_agent_t *rdap)
64 {
65
66 if (rdap->rda_procstat != NULL)
67 procstat_close(rdap->rda_procstat);
68 free(rdap);
69 }
70
71 const char *
rd_errstr(rd_err_e rderr)72 rd_errstr(rd_err_e rderr)
73 {
74
75 switch (rderr) {
76 case RD_ERR:
77 return "generic error";
78 case RD_OK:
79 return "no error";
80 case RD_NOCAPAB:
81 return "capability not supported";
82 case RD_DBERR:
83 return "database error";
84 case RD_NOBASE:
85 return "NOBASE";
86 case RD_NOMAPS:
87 return "NOMAPS";
88 default:
89 return "unknown error";
90 }
91 }
92
93 rd_err_e
rd_event_addr(rd_agent_t * rdap,rd_event_e event,rd_notify_t * notify)94 rd_event_addr(rd_agent_t *rdap, rd_event_e event, rd_notify_t *notify)
95 {
96 rd_err_e ret;
97
98 DPRINTF("%s rdap %p event %d notify %p\n", __func__, rdap, event,
99 notify);
100
101 ret = RD_OK;
102 switch (event) {
103 case RD_NONE:
104 break;
105 case RD_PREINIT:
106 notify->type = RD_NOTIFY_BPT;
107 notify->u.bptaddr = rdap->rda_preinit_addr;
108 break;
109 case RD_POSTINIT:
110 notify->type = RD_NOTIFY_BPT;
111 notify->u.bptaddr = rdap->rda_postinit_addr;
112 break;
113 case RD_DLACTIVITY:
114 notify->type = RD_NOTIFY_BPT;
115 notify->u.bptaddr = rdap->rda_dlactivity_addr;
116 break;
117 default:
118 ret = RD_ERR;
119 break;
120 }
121 return (ret);
122 }
123
124 rd_err_e
rd_event_enable(rd_agent_t * rdap __unused,int onoff)125 rd_event_enable(rd_agent_t *rdap __unused, int onoff)
126 {
127 DPRINTF("%s onoff %d\n", __func__, onoff);
128
129 return (RD_OK);
130 }
131
132 rd_err_e
rd_event_getmsg(rd_agent_t * rdap __unused,rd_event_msg_t * msg)133 rd_event_getmsg(rd_agent_t *rdap __unused, rd_event_msg_t *msg)
134 {
135 DPRINTF("%s\n", __func__);
136
137 msg->type = RD_POSTINIT;
138 msg->u.state = RD_CONSISTENT;
139
140 return (RD_OK);
141 }
142
143 rd_err_e
rd_init(int version)144 rd_init(int version)
145 {
146 char *debug = NULL;
147
148 if (version == RD_VERSION) {
149 debug = getenv("LIBRTLD_DB_DEBUG");
150 _librtld_db_debug = debug ? atoi(debug) : 0;
151 return (RD_OK);
152 } else
153 return (RD_NOCAPAB);
154 }
155
156 rd_err_e
rd_loadobj_iter(rd_agent_t * rdap,rl_iter_f * cb,void * clnt_data)157 rd_loadobj_iter(rd_agent_t *rdap, rl_iter_f *cb, void *clnt_data)
158 {
159 struct kinfo_vmentry *kves, *kve;
160 const char *path;
161 uint64_t fileid;
162 rd_loadobj_t rdl;
163 rd_err_e ret;
164 uintptr_t base;
165 uint32_t offset;
166 int cnt, i;
167
168 DPRINTF("%s\n", __func__);
169
170 if ((kves = kinfo_getvmmap(proc_getpid(rdap->rda_php), &cnt)) == NULL) {
171 warn("ERROR: kinfo_getvmmap() failed");
172 return (RD_ERR);
173 }
174
175 base = 0;
176 fileid = 0;
177 path = NULL;
178 ret = RD_OK;
179 for (i = 0; i < cnt; i++) {
180 kve = &kves[i];
181 /*
182 * Cache the base offset of the file mapping. The kve_offset
183 * field gives the file offset of a particular mapping into the
184 * file, but we want the mapping offset relative to the base
185 * mapping.
186 */
187 if (kve->kve_type == KVME_TYPE_VNODE) {
188 if (kve->kve_vn_fileid != fileid) {
189 base = kve->kve_start;
190 fileid = kve->kve_vn_fileid;
191 }
192 path = kve->kve_path;
193 offset = kve->kve_start - base;
194 } else {
195 path = NULL;
196 offset = 0;
197 }
198 memset(&rdl, 0, sizeof(rdl));
199 /*
200 * Map the kinfo_vmentry struct to the rd_loadobj structure.
201 */
202 rdl.rdl_saddr = kve->kve_start;
203 rdl.rdl_eaddr = kve->kve_end;
204 rdl.rdl_offset = offset;
205 if (kve->kve_protection & KVME_PROT_READ)
206 rdl.rdl_prot |= RD_RDL_R;
207 if (kve->kve_protection & KVME_PROT_WRITE)
208 rdl.rdl_prot |= RD_RDL_W;
209 if (kve->kve_protection & KVME_PROT_EXEC)
210 rdl.rdl_prot |= RD_RDL_X;
211 if (path != NULL)
212 strlcpy(rdl.rdl_path, path, sizeof(rdl.rdl_path));
213 if ((*cb)(&rdl, clnt_data) != 0) {
214 ret = RD_ERR;
215 break;
216 }
217 }
218 free(kves);
219 return (ret);
220 }
221
222 void
rd_log(const int onoff)223 rd_log(const int onoff)
224 {
225 DPRINTF("%s\n", __func__);
226
227 (void)onoff;
228 }
229
230 rd_agent_t *
rd_new(struct proc_handle * php)231 rd_new(struct proc_handle *php)
232 {
233 rd_agent_t *rdap;
234
235 rdap = malloc(sizeof(*rdap));
236 if (rdap == NULL)
237 return (NULL);
238
239 memset(rdap, 0, sizeof(rd_agent_t));
240 rdap->rda_php = php;
241 rdap->rda_procstat = procstat_open_sysctl();
242
243 if (rd_reset(rdap) != RD_OK) {
244 rd_delete(rdap);
245 rdap = NULL;
246 }
247 return (rdap);
248 }
249
250 rd_err_e
rd_objpad_enable(rd_agent_t * rdap,size_t padsize)251 rd_objpad_enable(rd_agent_t *rdap, size_t padsize)
252 {
253 DPRINTF("%s\n", __func__);
254
255 (void)rdap;
256 (void)padsize;
257
258 return (RD_ERR);
259 }
260
261 rd_err_e
rd_plt_resolution(rd_agent_t * rdap,uintptr_t pc,struct proc * proc,uintptr_t plt_base,rd_plt_info_t * rpi)262 rd_plt_resolution(rd_agent_t *rdap, uintptr_t pc, struct proc *proc,
263 uintptr_t plt_base, rd_plt_info_t *rpi)
264 {
265 DPRINTF("%s\n", __func__);
266
267 (void)rdap;
268 (void)pc;
269 (void)proc;
270 (void)plt_base;
271 (void)rpi;
272
273 return (RD_ERR);
274 }
275
276 static int
rtld_syms(rd_agent_t * rdap,const char * rtldpath,u_long base)277 rtld_syms(rd_agent_t *rdap, const char *rtldpath, u_long base)
278 {
279 GElf_Shdr shdr;
280 GElf_Sym sym;
281 Elf *e;
282 Elf_Data *data;
283 Elf_Scn *scn;
284 const char *symname;
285 Elf64_Word strscnidx;
286 int fd, i, ret;
287
288 ret = 1;
289 e = NULL;
290
291 fd = open(rtldpath, O_RDONLY);
292 if (fd < 0)
293 goto err;
294
295 if (elf_version(EV_CURRENT) == EV_NONE)
296 goto err;
297 e = elf_begin(fd, ELF_C_READ, NULL);
298 if (e == NULL)
299 goto err;
300
301 scn = NULL;
302 while ((scn = elf_nextscn(e, scn)) != NULL) {
303 gelf_getshdr(scn, &shdr);
304 if (shdr.sh_type == SHT_DYNSYM)
305 break;
306 }
307 if (scn == NULL)
308 goto err;
309
310 strscnidx = shdr.sh_link;
311 data = elf_getdata(scn, NULL);
312 if (data == NULL)
313 goto err;
314
315 for (i = 0; gelf_getsym(data, i, &sym) != NULL; i++) {
316 if (GELF_ST_TYPE(sym.st_info) != STT_FUNC ||
317 GELF_ST_BIND(sym.st_info) != STB_GLOBAL)
318 continue;
319 symname = elf_strptr(e, strscnidx, sym.st_name);
320 if (symname == NULL)
321 continue;
322
323 if (strcmp(symname, "r_debug_state") == 0) {
324 rdap->rda_preinit_addr = sym.st_value + base;
325 rdap->rda_dlactivity_addr = sym.st_value + base;
326 } else if (strcmp(symname, "_r_debug_postinit") == 0) {
327 rdap->rda_postinit_addr = sym.st_value + base;
328 }
329 }
330
331 if (rdap->rda_preinit_addr != 0 &&
332 rdap->rda_postinit_addr != 0 &&
333 rdap->rda_dlactivity_addr != 0)
334 ret = 0;
335
336 err:
337 if (e != NULL)
338 (void)elf_end(e);
339 if (fd >= 0)
340 (void)close(fd);
341 return (ret);
342 }
343
344 rd_err_e
rd_reset(rd_agent_t * rdap)345 rd_reset(rd_agent_t *rdap)
346 {
347 struct kinfo_proc *kp;
348 struct kinfo_vmentry *kve;
349 Elf_Auxinfo *auxv;
350 const char *rtldpath;
351 u_long base;
352 rd_err_e rderr;
353 int count, i;
354
355 kp = NULL;
356 auxv = NULL;
357 kve = NULL;
358 rderr = RD_ERR;
359
360 kp = procstat_getprocs(rdap->rda_procstat, KERN_PROC_PID,
361 proc_getpid(rdap->rda_php), &count);
362 if (kp == NULL)
363 return (RD_ERR);
364 assert(count == 1);
365
366 auxv = procstat_getauxv(rdap->rda_procstat, kp, &count);
367 if (auxv == NULL)
368 goto err;
369
370 base = 0;
371 for (i = 0; i < count; i++) {
372 if (auxv[i].a_type == AT_BASE) {
373 base = auxv[i].a_un.a_val;
374 break;
375 }
376 }
377 if (i == count)
378 goto err;
379
380 rtldpath = NULL;
381 kve = procstat_getvmmap(rdap->rda_procstat, kp, &count);
382 if (kve == NULL)
383 goto err;
384 for (i = 0; i < count; i++) {
385 if (kve[i].kve_start == base) {
386 rtldpath = kve[i].kve_path;
387 break;
388 }
389 }
390 if (i == count)
391 goto err;
392
393 if (rtld_syms(rdap, rtldpath, base) != 0)
394 goto err;
395
396 rderr = RD_OK;
397
398 err:
399 if (kve != NULL)
400 procstat_freevmmap(rdap->rda_procstat, kve);
401 if (auxv != NULL)
402 procstat_freeauxv(rdap->rda_procstat, auxv);
403 if (kp != NULL)
404 procstat_freeprocs(rdap->rda_procstat, kp);
405 return (rderr);
406 }
407