2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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.
28 #ifndef RTLD_H /* { */
31 #include <machine/elf.h>
32 #include <sys/types.h>
33 #include <sys/queue.h>
35 #include <elf-hints.h>
41 #include "rtld_lock.h"
42 #include "rtld_machdep.h"
45 #undef STANDARD_LIBRARY_PATH
46 #undef _PATH_ELF_HINTS
47 #define _PATH_ELF_HINTS "/var/run/ld-elf32.so.hints"
48 /* For running 32 bit binaries */
49 #define STANDARD_LIBRARY_PATH "/lib32:/usr/lib32"
53 #ifndef STANDARD_LIBRARY_PATH
54 #define STANDARD_LIBRARY_PATH "/lib:/usr/lib"
60 #define NEW(type) ((type *) xmalloc(sizeof(type)))
61 #define CNEW(type) ((type *) xcalloc(1, sizeof(type)))
63 /* We might as well do booleans like C++. */
64 typedef unsigned char bool;
68 extern size_t tls_last_offset;
69 extern size_t tls_last_size;
70 extern size_t tls_static_space;
71 extern int tls_dtv_generation;
72 extern int tls_max_index;
74 extern int npagesizes;
75 extern size_t *pagesizes;
78 extern char **main_argv;
79 extern char **environ;
82 struct Struct_Obj_Entry;
84 /* Lists of shared objects */
85 typedef struct Struct_Objlist_Entry {
86 STAILQ_ENTRY(Struct_Objlist_Entry) link;
87 struct Struct_Obj_Entry *obj;
90 typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist;
92 /* Types of init and fini functions */
93 typedef void (*InitFunc)(void);
94 typedef void (*InitArrFunc)(int, char **, char **);
96 /* Lists of shared object dependencies */
97 typedef struct Struct_Needed_Entry {
98 struct Struct_Needed_Entry *next;
99 struct Struct_Obj_Entry *obj;
100 unsigned long name; /* Offset of name in string table */
103 typedef struct Struct_Name_Entry {
104 STAILQ_ENTRY(Struct_Name_Entry) link;
109 typedef struct Struct_LockInfo {
110 void *context; /* Client context for creating locks */
111 void *thelock; /* The one big lock */
112 /* Debugging aids. */
113 volatile int rcount; /* Number of readers holding lock */
114 volatile int wcount; /* Number of writers holding lock */
116 void *(*lock_create)(void *context);
117 void (*rlock_acquire)(void *lock);
118 void (*wlock_acquire)(void *lock);
119 void (*rlock_release)(void *lock);
120 void (*wlock_release)(void *lock);
121 void (*lock_destroy)(void *lock);
122 void (*context_destroy)(void *context);
125 typedef struct Struct_Ver_Entry {
132 typedef struct Struct_Sym_Match_Result {
133 const Elf_Sym *sym_out;
134 const Elf_Sym *vsymp;
138 #define VER_INFO_HIDDEN 0x01
141 * Shared object descriptor.
143 * Items marked with "(%)" are dynamically allocated, and must be freed
144 * when the structure is destroyed.
146 * CAUTION: It appears that the JDK port peeks into these structures.
147 * It looks at "next" and "mapbase" at least. Don't add new members
148 * near the front, until this can be straightened out.
150 typedef struct Struct_Obj_Entry {
152 * These two items have to be set right for compatibility with the
153 * original ElfKit crt1.o.
155 Elf_Size magic; /* Magic number (sanity check) */
156 Elf_Size version; /* Version number of struct format */
158 struct Struct_Obj_Entry *next;
159 char *path; /* Pathname of underlying file (%) */
160 char *origin_path; /* Directory path of origin file */
162 int dl_refcount; /* Number of times loaded by dlopen */
164 /* These items are computed by map_object() or by digest_phdr(). */
165 caddr_t mapbase; /* Base address of mapped region */
166 size_t mapsize; /* Size of mapped region in bytes */
167 size_t textsize; /* Size of text segment in bytes */
168 Elf_Addr vaddrbase; /* Base address in shared object file */
169 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */
170 const Elf_Dyn *dynamic; /* Dynamic section */
171 caddr_t entry; /* Entry point */
172 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */
173 size_t phsize; /* Size of program header in bytes */
174 const char *interp; /* Pathname of the interpreter, if any */
175 Elf_Word stack_flags;
177 /* TLS information */
178 int tlsindex; /* Index in DTV for this module */
179 void *tlsinit; /* Base address of TLS init block */
180 size_t tlsinitsize; /* Size of TLS init block for this module */
181 size_t tlssize; /* Size of TLS block for this module */
182 size_t tlsoffset; /* Offset of static TLS block for this module */
183 size_t tlsalign; /* Alignment of static TLS block */
188 /* Items from the dynamic section. */
189 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */
190 const Elf_Rel *rel; /* Relocation entries */
191 unsigned long relsize; /* Size in bytes of relocation info */
192 const Elf_Rela *rela; /* Relocation entries with addend */
193 unsigned long relasize; /* Size in bytes of addend relocation info */
194 const Elf_Rel *pltrel; /* PLT relocation entries */
195 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */
196 const Elf_Rela *pltrela; /* PLT relocation entries with addend */
197 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */
198 const Elf_Sym *symtab; /* Symbol table */
199 const char *strtab; /* String table */
200 unsigned long strsize; /* Size in bytes of string table */
202 Elf_Word local_gotno; /* Number of local GOT entries */
203 Elf_Word symtabno; /* Number of dynamic symbols */
204 Elf_Word gotsym; /* First dynamic symbol in GOT */
207 const Elf_Verneed *verneed; /* Required versions. */
208 Elf_Word verneednum; /* Number of entries in verneed table */
209 const Elf_Verdef *verdef; /* Provided versions. */
210 Elf_Word verdefnum; /* Number of entries in verdef table */
211 const Elf_Versym *versyms; /* Symbol versions table */
213 const Elf_Hashelt *buckets; /* Hash table buckets array */
214 unsigned long nbuckets; /* Number of buckets */
215 const Elf_Hashelt *chains; /* Hash table chain array */
216 unsigned long nchains; /* Number of entries in chain array */
218 Elf32_Word nbuckets_gnu; /* Number of GNU hash buckets*/
219 Elf32_Word symndx_gnu; /* 1st accessible symbol on dynsym table */
220 Elf32_Word maskwords_bm_gnu; /* Bloom filter words - 1 (bitmask) */
221 Elf32_Word shift2_gnu; /* Bloom filter shift count */
222 Elf32_Word dynsymcount; /* Total entries in dynsym table */
223 Elf_Addr *bloom_gnu; /* Bloom filter used by GNU hash func */
224 const Elf_Hashelt *buckets_gnu; /* GNU hash table bucket array */
225 const Elf_Hashelt *chain_zero_gnu; /* GNU hash table value array (Zeroed) */
227 char *rpath; /* Search path specified in object */
228 char *runpath; /* Search path with different priority */
229 Needed_Entry *needed; /* Shared objects needed by this one (%) */
230 Needed_Entry *needed_filtees;
231 Needed_Entry *needed_aux_filtees;
233 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we
235 Ver_Entry *vertab; /* Versions required /defined by this object */
236 int vernum; /* Number of entries in vertab */
238 Elf_Addr init; /* Initialization function to call */
239 Elf_Addr fini; /* Termination function to call */
240 Elf_Addr preinit_array; /* Pre-initialization array of functions */
241 Elf_Addr init_array; /* Initialization array of functions */
242 Elf_Addr fini_array; /* Termination array of functions */
243 int preinit_array_num; /* Number of entries in preinit_array */
244 int init_array_num; /* Number of entries in init_array */
245 int fini_array_num; /* Number of entries in fini_array */
247 int32_t osrel; /* OSREL note value */
249 bool mainprog : 1; /* True if this is the main program */
250 bool rtld : 1; /* True if this is the dynamic linker */
251 bool relocated : 1; /* True if processed by relocate_objects() */
252 bool ver_checked : 1; /* True if processed by rtld_verify_object_versions */
253 bool textrel : 1; /* True if there are relocations to text seg */
254 bool symbolic : 1; /* True if generated with "-Bsymbolic" */
255 bool bind_now : 1; /* True if all relocations should be made first */
256 bool traced : 1; /* Already printed in ldd trace output */
257 bool jmpslots_done : 1; /* Already have relocated the jump slots */
258 bool init_done : 1; /* Already have added object to init list */
259 bool tls_done : 1; /* Already allocated offset for static TLS */
260 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */
261 bool z_origin : 1; /* Process rpath and soname tokens */
262 bool z_nodelete : 1; /* Do not unload the object and dependencies */
263 bool z_noopen : 1; /* Do not load on dlopen */
264 bool z_loadfltr : 1; /* Immediately load filtees */
265 bool z_interpose : 1; /* Interpose all objects but main */
266 bool z_nodeflib : 1; /* Don't search default library path */
267 bool z_global : 1; /* Make the object global */
268 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */
269 bool init_scanned: 1; /* Object is already on init list. */
270 bool on_fini_list: 1; /* Object is already on fini list. */
271 bool dag_inited : 1; /* Object has its DAG initialized. */
272 bool filtees_loaded : 1; /* Filtees loaded */
273 bool irelative : 1; /* Object has R_MACHDEP_IRELATIVE relocs */
274 bool gnu_ifunc : 1; /* Object has references to STT_GNU_IFUNC */
275 bool non_plt_gnu_ifunc : 1; /* Object has non-plt IFUNC references */
276 bool crt_no_init : 1; /* Object' crt does not call _init/_fini */
277 bool valid_hash_sysv : 1; /* A valid System V hash hash tag is available */
278 bool valid_hash_gnu : 1; /* A valid GNU hash tag is available */
279 bool dlopened : 1; /* dlopen()-ed (vs. load statically) */
281 struct link_map linkmap; /* For GDB and dlinfo() */
282 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */
283 Objlist dagmembers; /* DAG has these members (%) */
284 dev_t dev; /* Object's filesystem's device */
285 ino_t ino; /* Object's inode number */
286 void *priv; /* Platform-dependent */
289 #define RTLD_MAGIC 0xd550b87a
290 #define RTLD_VERSION 1
292 #define RTLD_STATIC_TLS_EXTRA 128
294 /* Flags to be passed into symlook_ family of functions. */
295 #define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */
296 #define SYMLOOK_DLSYM 0x02 /* Return newest versioned symbol. Used by
298 #define SYMLOOK_EARLY 0x04 /* Symlook is done during initialization. */
299 #define SYMLOOK_IFUNC 0x08 /* Allow IFUNC processing in
302 /* Flags for load_object(). */
303 #define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */
304 #define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */
305 #define RTLD_LO_TRACE 0x04 /* Only tracing. */
306 #define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */
307 #define RTLD_LO_FILTEES 0x10 /* Loading filtee. */
308 #define RTLD_LO_EARLY 0x20 /* Do not call ctors, postpone it to the
309 initialization during the image start. */
312 * Symbol cache entry used during relocation to avoid multiple lookups
313 * of the same symbol.
315 typedef struct Struct_SymCache {
316 const Elf_Sym *sym; /* Symbol table entry */
317 const Obj_Entry *obj; /* Shared object which defines it */
321 * This structure provides a reentrant way to keep a list of objects and
322 * check which ones have already been processed in some way.
324 typedef struct Struct_DoneList {
325 const Obj_Entry **objs; /* Array of object pointers */
326 unsigned int num_alloc; /* Allocated size of the array */
327 unsigned int num_used; /* Number of array slots used */
330 struct Struct_RtldLockState {
335 struct fill_search_info_args {
338 struct dl_serinfo *serinfo;
339 struct dl_serpath *serpath;
344 * The pack of arguments and results for the symbol lookup functions.
346 typedef struct Struct_SymLook {
350 const Ver_Entry *ventry;
352 const Obj_Entry *defobj_out;
353 const Elf_Sym *sym_out;
354 struct Struct_RtldLockState *lockstate;
357 void _rtld_error(const char *, ...) __printflike(1, 2) __exported;
358 void rtld_die(void) __dead2;
359 const char *rtld_strerror(int);
360 Obj_Entry *map_object(int, const char *, const struct stat *);
361 void *xcalloc(size_t, size_t);
362 void *xmalloc(size_t);
363 char *xstrdup(const char *);
364 void *malloc_aligned(size_t size, size_t align);
365 void free_aligned(void *ptr);
366 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[];
367 extern Elf_Sym sym_zero; /* For resolving undefined weak refs. */
369 void dump_relocations(Obj_Entry *);
370 void dump_obj_relocations(Obj_Entry *);
371 void dump_Elf_Rel(Obj_Entry *, const Elf_Rel *, u_long);
372 void dump_Elf_Rela(Obj_Entry *, const Elf_Rela *, u_long);
375 * Function declarations.
377 unsigned long elf_hash(const char *);
378 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *,
379 const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *);
380 void init_pltgot(Obj_Entry *);
381 void lockdflt_init(void);
382 void digest_notes(Obj_Entry *, Elf_Addr, Elf_Addr);
383 void obj_free(Obj_Entry *);
384 Obj_Entry *obj_new(void);
385 void _rtld_bind_start(void);
386 void *rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def);
387 void symlook_init(SymLook *, const char *);
388 int symlook_obj(SymLook *, const Obj_Entry *);
389 void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset);
390 void *allocate_tls(Obj_Entry *, void *, size_t, size_t);
391 void free_tls(void *, size_t, size_t);
392 void *allocate_module_tls(int index);
393 bool allocate_tls_offset(Obj_Entry *obj);
394 void free_tls_offset(Obj_Entry *obj);
395 const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long);
398 * MD function declarations.
400 int do_copy_relocations(Obj_Entry *);
401 int reloc_non_plt(Obj_Entry *, Obj_Entry *, int flags,
402 struct Struct_RtldLockState *);
403 int reloc_plt(Obj_Entry *);
404 int reloc_jmpslots(Obj_Entry *, int flags, struct Struct_RtldLockState *);
405 int reloc_iresolve(Obj_Entry *, struct Struct_RtldLockState *);
406 int reloc_gnu_ifunc(Obj_Entry *, int flags, struct Struct_RtldLockState *);
407 void allocate_initial_tls(Obj_Entry *);