1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 * 25 * $FreeBSD$ 26 */ 27 28 #ifndef RTLD_H /* { */ 29 #define RTLD_H 1 30 31 #include <machine/elf.h> 32 #include <sys/types.h> 33 #include <sys/queue.h> 34 35 #include <elf-hints.h> 36 #include <link.h> 37 #include <stdarg.h> 38 #include <setjmp.h> 39 #include <stddef.h> 40 41 #include "rtld_lock.h" 42 #include "rtld_machdep.h" 43 44 #ifndef STANDARD_LIBRARY_PATH 45 #define STANDARD_LIBRARY_PATH "/usr/lib" 46 #endif 47 48 #define NEW(type) ((type *) xmalloc(sizeof(type))) 49 #define CNEW(type) ((type *) xcalloc(sizeof(type))) 50 51 /* We might as well do booleans like C++. */ 52 typedef unsigned char bool; 53 #define false 0 54 #define true 1 55 56 extern size_t tls_last_offset; 57 extern size_t tls_last_size; 58 extern size_t tls_static_space; 59 extern int tls_dtv_generation; 60 extern int tls_max_index; 61 62 struct stat; 63 struct Struct_Obj_Entry; 64 65 /* Lists of shared objects */ 66 typedef struct Struct_Objlist_Entry { 67 STAILQ_ENTRY(Struct_Objlist_Entry) link; 68 struct Struct_Obj_Entry *obj; 69 } Objlist_Entry; 70 71 typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; 72 73 /* Types of init and fini functions */ 74 typedef void (*InitFunc)(void); 75 76 /* Lists of shared object dependencies */ 77 typedef struct Struct_Needed_Entry { 78 struct Struct_Needed_Entry *next; 79 struct Struct_Obj_Entry *obj; 80 unsigned long name; /* Offset of name in string table */ 81 } Needed_Entry; 82 83 typedef struct Struct_Name_Entry { 84 STAILQ_ENTRY(Struct_Name_Entry) link; 85 char name[1]; 86 } Name_Entry; 87 88 /* Lock object */ 89 typedef struct Struct_LockInfo { 90 void *context; /* Client context for creating locks */ 91 void *thelock; /* The one big lock */ 92 /* Debugging aids. */ 93 volatile int rcount; /* Number of readers holding lock */ 94 volatile int wcount; /* Number of writers holding lock */ 95 /* Methods */ 96 void *(*lock_create)(void *context); 97 void (*rlock_acquire)(void *lock); 98 void (*wlock_acquire)(void *lock); 99 void (*rlock_release)(void *lock); 100 void (*wlock_release)(void *lock); 101 void (*lock_destroy)(void *lock); 102 void (*context_destroy)(void *context); 103 } LockInfo; 104 105 typedef struct Struct_Ver_Entry { 106 Elf_Word hash; 107 unsigned int flags; 108 const char *name; 109 const char *file; 110 } Ver_Entry; 111 112 #define VER_INFO_HIDDEN 0x01 113 114 /* 115 * Shared object descriptor. 116 * 117 * Items marked with "(%)" are dynamically allocated, and must be freed 118 * when the structure is destroyed. 119 * 120 * CAUTION: It appears that the JDK port peeks into these structures. 121 * It looks at "next" and "mapbase" at least. Don't add new members 122 * near the front, until this can be straightened out. 123 */ 124 typedef struct Struct_Obj_Entry { 125 /* 126 * These two items have to be set right for compatibility with the 127 * original ElfKit crt1.o. 128 */ 129 Elf_Size magic; /* Magic number (sanity check) */ 130 Elf_Size version; /* Version number of struct format */ 131 132 struct Struct_Obj_Entry *next; 133 char *path; /* Pathname of underlying file (%) */ 134 char *origin_path; /* Directory path of origin file */ 135 int refcount; 136 int dl_refcount; /* Number of times loaded by dlopen */ 137 138 /* These items are computed by map_object() or by digest_phdr(). */ 139 caddr_t mapbase; /* Base address of mapped region */ 140 size_t mapsize; /* Size of mapped region in bytes */ 141 size_t textsize; /* Size of text segment in bytes */ 142 Elf_Addr vaddrbase; /* Base address in shared object file */ 143 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */ 144 const Elf_Dyn *dynamic; /* Dynamic section */ 145 caddr_t entry; /* Entry point */ 146 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */ 147 size_t phsize; /* Size of program header in bytes */ 148 const char *interp; /* Pathname of the interpreter, if any */ 149 caddr_t relro_page; /* Address of first page of read-only data */ 150 size_t relro_size; /* Size of relro page(s) in bytes */ 151 Elf_Word stack_flags; 152 153 /* TLS information */ 154 int tlsindex; /* Index in DTV for this module */ 155 void *tlsinit; /* Base address of TLS init block */ 156 size_t tlsinitsize; /* Size of TLS init block for this module */ 157 size_t tlssize; /* Size of TLS block for this module */ 158 size_t tlsoffset; /* Offset of static TLS block for this module */ 159 size_t tlsalign; /* Alignment of static TLS block */ 160 161 /* Items from the dynamic section. */ 162 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */ 163 const Elf_Rel *rel; /* Relocation entries */ 164 unsigned long relsize; /* Size in bytes of relocation info */ 165 const Elf_Rela *rela; /* Relocation entries with addend */ 166 unsigned long relasize; /* Size in bytes of addend relocation info */ 167 const Elf_Rel *pltrel; /* PLT relocation entries */ 168 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */ 169 const Elf_Rela *pltrela; /* PLT relocation entries with addend */ 170 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */ 171 const Elf_Sym *symtab; /* Symbol table */ 172 const char *strtab; /* String table */ 173 unsigned long strsize; /* Size in bytes of string table */ 174 175 const Elf_Verneed *verneed; /* Required versions. */ 176 Elf_Word verneednum; /* Number of entries in verneed table */ 177 const Elf_Verdef *verdef; /* Provided versions. */ 178 Elf_Word verdefnum; /* Number of entries in verdef table */ 179 const Elf_Versym *versyms; /* Symbol versions table */ 180 181 const Elf_Hashelt *buckets; /* Hash table buckets array */ 182 unsigned long nbuckets; /* Number of buckets */ 183 const Elf_Hashelt *chains; /* Hash table chain array */ 184 unsigned long nchains; /* Number of chains */ 185 186 char *rpath; /* Search path specified in object */ 187 Needed_Entry *needed; /* Shared objects needed by this one (%) */ 188 Needed_Entry *needed_filtees; 189 Needed_Entry *needed_aux_filtees; 190 191 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we 192 know about. */ 193 Ver_Entry *vertab; /* Versions required /defined by this object */ 194 int vernum; /* Number of entries in vertab */ 195 196 Elf_Addr init; /* Initialization function to call */ 197 Elf_Addr fini; /* Termination function to call */ 198 199 bool mainprog : 1; /* True if this is the main program */ 200 bool rtld : 1; /* True if this is the dynamic linker */ 201 bool textrel : 1; /* True if there are relocations to text seg */ 202 bool symbolic : 1; /* True if generated with "-Bsymbolic" */ 203 bool bind_now : 1; /* True if all relocations should be made first */ 204 bool traced : 1; /* Already printed in ldd trace output */ 205 bool jmpslots_done : 1; /* Already have relocated the jump slots */ 206 bool init_done : 1; /* Already have added object to init list */ 207 bool tls_done : 1; /* Already allocated offset for static TLS */ 208 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */ 209 bool z_origin : 1; /* Process rpath and soname tokens */ 210 bool z_nodelete : 1; /* Do not unload the object and dependencies */ 211 bool z_noopen : 1; /* Do not load on dlopen */ 212 bool z_loadfltr : 1; /* Immediately load filtees */ 213 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */ 214 bool init_scanned: 1; /* Object is already on init list. */ 215 bool on_fini_list: 1; /* Object is already on fini list. */ 216 bool dag_inited : 1; /* Object has its DAG initialized. */ 217 bool filtees_loaded : 1; /* Filtees loaded */ 218 bool irelative : 1; /* Object has R_MACHDEP_IRELATIVE relocs */ 219 bool gnu_ifunc : 1; /* Object has references to STT_GNU_IFUNC */ 220 221 struct link_map linkmap; /* For GDB and dlinfo() */ 222 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 223 Objlist dagmembers; /* DAG has these members (%) */ 224 dev_t dev; /* Object's filesystem's device */ 225 ino_t ino; /* Object's inode number */ 226 void *priv; /* Platform-dependent */ 227 } Obj_Entry; 228 229 #define RTLD_MAGIC 0xd550b87a 230 #define RTLD_VERSION 1 231 232 #define RTLD_FUNCTRACE "_rtld_functrace" 233 234 /* Flags to be passed into symlook_ family of functions. */ 235 #define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */ 236 #define SYMLOOK_DLSYM 0x02 /* Return newest versioned symbol. Used by 237 dlsym. */ 238 239 /* Flags for load_object(). */ 240 #define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */ 241 #define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */ 242 #define RTLD_LO_TRACE 0x04 /* Only tracing. */ 243 #define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */ 244 #define RTLD_LO_FILTEES 0x10 /* Loading filtee. */ 245 246 /* 247 * Symbol cache entry used during relocation to avoid multiple lookups 248 * of the same symbol. 249 */ 250 typedef struct Struct_SymCache { 251 const Elf_Sym *sym; /* Symbol table entry */ 252 const Obj_Entry *obj; /* Shared object which defines it */ 253 } SymCache; 254 255 /* 256 * This structure provides a reentrant way to keep a list of objects and 257 * check which ones have already been processed in some way. 258 */ 259 typedef struct Struct_DoneList { 260 const Obj_Entry **objs; /* Array of object pointers */ 261 unsigned int num_alloc; /* Allocated size of the array */ 262 unsigned int num_used; /* Number of array slots used */ 263 } DoneList; 264 265 struct Struct_RtldLockState { 266 int lockstate; 267 sigjmp_buf env; 268 }; 269 270 /* 271 * The pack of arguments and results for the symbol lookup functions. 272 */ 273 typedef struct Struct_SymLook { 274 const char *name; 275 unsigned long hash; 276 const Ver_Entry *ventry; 277 int flags; 278 const Obj_Entry *defobj_out; 279 const Elf_Sym *sym_out; 280 struct Struct_RtldLockState *lockstate; 281 } SymLook; 282 283 void _rtld_error(const char *, ...) __printflike(1, 2); 284 Obj_Entry *map_object(int, const char *, const struct stat *); 285 void *xcalloc(size_t); 286 void *xmalloc(size_t); 287 char *xstrdup(const char *); 288 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 289 290 void dump_relocations(Obj_Entry *); 291 void dump_obj_relocations(Obj_Entry *); 292 void dump_Elf_Rel(Obj_Entry *, const Elf_Rel *, u_long); 293 void dump_Elf_Rela(Obj_Entry *, const Elf_Rela *, u_long); 294 295 /* 296 * Function declarations. 297 */ 298 const char *basename(const char *); 299 unsigned long elf_hash(const char *); 300 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, 301 const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *); 302 void init_pltgot(Obj_Entry *); 303 void lockdflt_init(void); 304 void obj_free(Obj_Entry *); 305 Obj_Entry *obj_new(void); 306 void _rtld_bind_start(void); 307 void *rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def); 308 void symlook_init(SymLook *, const char *); 309 int symlook_obj(SymLook *, const Obj_Entry *); 310 void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset); 311 struct tls_tcb *allocate_tls(Obj_Entry *); 312 void free_tls(struct tls_tcb *); 313 void *allocate_module_tls(int index); 314 bool allocate_tls_offset(Obj_Entry *obj); 315 void free_tls_offset(Obj_Entry *obj); 316 const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long); 317 318 /* 319 * MD function declarations. 320 */ 321 int do_copy_relocations(Obj_Entry *); 322 int reloc_non_plt(Obj_Entry *, Obj_Entry *, struct Struct_RtldLockState *); 323 int reloc_plt(Obj_Entry *); 324 int reloc_jmpslots(Obj_Entry *, struct Struct_RtldLockState *); 325 int reloc_iresolve(Obj_Entry *, struct Struct_RtldLockState *); 326 int reloc_gnu_ifunc(Obj_Entry *, struct Struct_RtldLockState *); 327 void allocate_initial_tls(Obj_Entry *); 328 329 #endif /* } */ 330