2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 * Dynamic linker for ELF.
32 * John Polstra <jdp@polstra.com>.
36 #error "GCC is needed to compile this file"
39 #include <sys/param.h>
40 #include <sys/mount.h>
44 #include <sys/ktrace.h>
62 #define PATH_RTLD "/libexec/ld-elf.so.1"
64 #define PATH_RTLD "/libexec/ld-elf32.so.1"
68 typedef void (*func_ptr_type)();
69 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
72 * This structure provides a reentrant way to keep a list of objects and
73 * check which ones have already been processed in some way.
75 typedef struct Struct_DoneList {
76 const Obj_Entry **objs; /* Array of object pointers */
77 unsigned int num_alloc; /* Allocated size of the array */
78 unsigned int num_used; /* Number of array slots used */
82 * Function declarations.
84 static const char *basename(const char *);
85 static void die(void) __dead2;
86 static void digest_dynamic(Obj_Entry *, int);
87 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
88 static Obj_Entry *dlcheck(void *);
89 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *);
90 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
91 static bool donelist_check(DoneList *, const Obj_Entry *);
92 static void errmsg_restore(char *);
93 static char *errmsg_save(void);
94 static void *fill_search_info(const char *, size_t, void *);
95 static char *find_library(const char *, const Obj_Entry *);
96 static const char *gethints(void);
97 static void init_dag(Obj_Entry *);
98 static void init_dag1(Obj_Entry *, Obj_Entry *, DoneList *);
99 static void init_rtld(caddr_t);
100 static void initlist_add_neededs(Needed_Entry *, Objlist *);
101 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
102 static bool is_exported(const Elf_Sym *);
103 static void linkmap_add(Obj_Entry *);
104 static void linkmap_delete(Obj_Entry *);
105 static int load_needed_objects(Obj_Entry *);
106 static int load_preload_objects(void);
107 static Obj_Entry *load_object(const char *, const Obj_Entry *);
108 static Obj_Entry *obj_from_addr(const void *);
109 static void objlist_call_fini(Objlist *, int *lockstate);
110 static void objlist_call_init(Objlist *, int *lockstate);
111 static void objlist_clear(Objlist *);
112 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
113 static void objlist_init(Objlist *);
114 static void objlist_push_head(Objlist *, Obj_Entry *);
115 static void objlist_push_tail(Objlist *, Obj_Entry *);
116 static void objlist_remove(Objlist *, Obj_Entry *);
117 static void objlist_remove_unref(Objlist *);
118 static void *path_enumerate(const char *, path_enum_proc, void *);
119 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *);
120 static int rtld_dirname(const char *, char *);
121 static void rtld_exit(void);
122 static char *search_library_path(const char *, const char *);
123 static const void **get_program_var_addr(const char *);
124 static void set_program_var(const char *, const void *);
125 static const Elf_Sym *symlook_default(const char *, unsigned long,
126 const Obj_Entry *, const Obj_Entry **, const Ver_Entry *, int);
127 static const Elf_Sym *symlook_list(const char *, unsigned long, const Objlist *,
128 const Obj_Entry **, const Ver_Entry *, int, DoneList *);
129 static const Elf_Sym *symlook_needed(const char *, unsigned long,
130 const Needed_Entry *, const Obj_Entry **, const Ver_Entry *,
132 static void trace_loaded_objects(Obj_Entry *);
133 static void unlink_object(Obj_Entry *);
134 static void unload_object(Obj_Entry *);
135 static void unref_dag(Obj_Entry *);
136 static void ref_dag(Obj_Entry *);
137 static int rtld_verify_versions(const Objlist *);
138 static int rtld_verify_object_versions(Obj_Entry *);
139 static void object_add_name(Obj_Entry *, const char *);
140 static int object_match_name(const Obj_Entry *, const char *);
141 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
143 void r_debug_state(struct r_debug *, struct link_map *);
148 static char *error_message; /* Message for dlerror(), or NULL */
149 struct r_debug r_debug; /* for GDB; */
150 static bool libmap_disable; /* Disable libmap */
151 static char *libmap_override; /* Maps to use in addition to libmap.conf */
152 static bool trust; /* False for setuid and setgid programs */
153 static bool dangerous_ld_env; /* True if environment variables have been
154 used to affect the libraries loaded */
155 static char *ld_bind_now; /* Environment variable for immediate binding */
156 static char *ld_debug; /* Environment variable for debugging */
157 static char *ld_library_path; /* Environment variable for search path */
158 static char *ld_preload; /* Environment variable for libraries to
160 static char *ld_tracing; /* Called from ldd to print libs */
161 static char *ld_utrace; /* Use utrace() to log events. */
162 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
163 static Obj_Entry **obj_tail; /* Link field of last object in list */
164 static Obj_Entry *obj_main; /* The main program shared object */
165 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
166 static unsigned int obj_count; /* Number of objects in obj_list */
167 static unsigned int obj_loads; /* Number of objects in obj_list */
169 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
170 STAILQ_HEAD_INITIALIZER(list_global);
171 static Objlist list_main = /* Objects loaded at program startup */
172 STAILQ_HEAD_INITIALIZER(list_main);
173 static Objlist list_fini = /* Objects needing fini() calls */
174 STAILQ_HEAD_INITIALIZER(list_fini);
176 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */
178 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
180 extern Elf_Dyn _DYNAMIC;
181 #pragma weak _DYNAMIC
182 #ifndef RTLD_IS_DYNAMIC
183 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
187 * These are the functions the dynamic linker exports to application
188 * programs. They are the only symbols the dynamic linker is willing
189 * to export from itself.
191 static func_ptr_type exports[] = {
192 (func_ptr_type) &_rtld_error,
193 (func_ptr_type) &dlclose,
194 (func_ptr_type) &dlerror,
195 (func_ptr_type) &dlopen,
196 (func_ptr_type) &dlsym,
197 (func_ptr_type) &dlvsym,
198 (func_ptr_type) &dladdr,
199 (func_ptr_type) &dllockinit,
200 (func_ptr_type) &dlinfo,
201 (func_ptr_type) &_rtld_thread_init,
203 (func_ptr_type) &___tls_get_addr,
205 (func_ptr_type) &__tls_get_addr,
206 (func_ptr_type) &_rtld_allocate_tls,
207 (func_ptr_type) &_rtld_free_tls,
208 (func_ptr_type) &dl_iterate_phdr,
209 (func_ptr_type) &_rtld_atfork_pre,
210 (func_ptr_type) &_rtld_atfork_post,
215 * Global declarations normally provided by crt1. The dynamic linker is
216 * not built with crt1, so we have to provide them ourselves.
222 * Globals to control TLS allocation.
224 size_t tls_last_offset; /* Static TLS offset of last module */
225 size_t tls_last_size; /* Static TLS size of last module */
226 size_t tls_static_space; /* Static TLS space allocated */
227 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
228 int tls_max_index = 1; /* Largest module index allocated */
231 * Fill in a DoneList with an allocation large enough to hold all of
232 * the currently-loaded objects. Keep this as a macro since it calls
233 * alloca and we want that to occur within the scope of the caller.
235 #define donelist_init(dlp) \
236 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
237 assert((dlp)->objs != NULL), \
238 (dlp)->num_alloc = obj_count, \
241 #define UTRACE_DLOPEN_START 1
242 #define UTRACE_DLOPEN_STOP 2
243 #define UTRACE_DLCLOSE_START 3
244 #define UTRACE_DLCLOSE_STOP 4
245 #define UTRACE_LOAD_OBJECT 5
246 #define UTRACE_UNLOAD_OBJECT 6
247 #define UTRACE_ADD_RUNDEP 7
248 #define UTRACE_PRELOAD_FINISHED 8
249 #define UTRACE_INIT_CALL 9
250 #define UTRACE_FINI_CALL 10
253 char sig[4]; /* 'RTLD' */
256 void *mapbase; /* Used for 'parent' and 'init/fini' */
258 int refcnt; /* Used for 'mode' */
259 char name[MAXPATHLEN];
262 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
263 if (ld_utrace != NULL) \
264 ld_utrace_log(e, h, mb, ms, r, n); \
268 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
269 int refcnt, const char *name)
271 struct utrace_rtld ut;
279 ut.mapbase = mapbase;
280 ut.mapsize = mapsize;
282 bzero(ut.name, sizeof(ut.name));
284 strlcpy(ut.name, name, sizeof(ut.name));
285 utrace(&ut, sizeof(ut));
289 * Main entry point for dynamic linking. The first argument is the
290 * stack pointer. The stack is expected to be laid out as described
291 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
292 * Specifically, the stack pointer points to a word containing
293 * ARGC. Following that in the stack is a null-terminated sequence
294 * of pointers to argument strings. Then comes a null-terminated
295 * sequence of pointers to environment strings. Finally, there is a
296 * sequence of "auxiliary vector" entries.
298 * The second argument points to a place to store the dynamic linker's
299 * exit procedure pointer and the third to a place to store the main
302 * The return value is the main program's entry point.
305 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
307 Elf_Auxinfo *aux_info[AT_COUNT];
315 Objlist_Entry *entry;
317 Obj_Entry **preload_tail;
322 * On entry, the dynamic linker itself has not been relocated yet.
323 * Be very careful not to reference any global data until after
324 * init_rtld has returned. It is OK to reference file-scope statics
325 * and string constants, and to call static and global functions.
328 /* Find the auxiliary vector on the stack. */
331 sp += argc + 1; /* Skip over arguments and NULL terminator */
333 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
335 aux = (Elf_Auxinfo *) sp;
337 /* Digest the auxiliary vector. */
338 for (i = 0; i < AT_COUNT; i++)
340 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
341 if (auxp->a_type < AT_COUNT)
342 aux_info[auxp->a_type] = auxp;
345 /* Initialize and relocate ourselves. */
346 assert(aux_info[AT_BASE] != NULL);
347 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
349 __progname = obj_rtld.path;
350 argv0 = argv[0] != NULL ? argv[0] : "(null)";
353 trust = !issetugid();
355 ld_bind_now = getenv(LD_ "BIND_NOW");
357 * If the process is tainted, then we un-set the dangerous environment
358 * variables. The process will be marked as tainted until setuid(2)
359 * is called. If any child process calls setuid(2) we do not want any
360 * future processes to honor the potentially un-safe variables.
363 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
364 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") ||
365 unsetenv(LD_ "DEBUG")) {
366 _rtld_error("environment corrupt; aborting");
370 ld_debug = getenv(LD_ "DEBUG");
371 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
372 libmap_override = getenv(LD_ "LIBMAP");
373 ld_library_path = getenv(LD_ "LIBRARY_PATH");
374 ld_preload = getenv(LD_ "PRELOAD");
375 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
376 (ld_library_path != NULL) || (ld_preload != NULL);
377 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
378 ld_utrace = getenv(LD_ "UTRACE");
380 if (ld_debug != NULL && *ld_debug != '\0')
382 dbg("%s is initialized, base address = %p", __progname,
383 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
384 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
385 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
388 * Load the main program, or process its program header if it is
391 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
392 int fd = aux_info[AT_EXECFD]->a_un.a_val;
393 dbg("loading main program");
394 obj_main = map_object(fd, argv0, NULL);
396 if (obj_main == NULL)
398 } else { /* Main program already loaded. */
399 const Elf_Phdr *phdr;
403 dbg("processing main program's program header");
404 assert(aux_info[AT_PHDR] != NULL);
405 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
406 assert(aux_info[AT_PHNUM] != NULL);
407 phnum = aux_info[AT_PHNUM]->a_un.a_val;
408 assert(aux_info[AT_PHENT] != NULL);
409 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
410 assert(aux_info[AT_ENTRY] != NULL);
411 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
412 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
416 obj_main->path = xstrdup(argv0);
417 obj_main->mainprog = true;
420 * Get the actual dynamic linker pathname from the executable if
421 * possible. (It should always be possible.) That ensures that
422 * gdb will find the right dynamic linker even if a non-standard
425 if (obj_main->interp != NULL &&
426 strcmp(obj_main->interp, obj_rtld.path) != 0) {
428 obj_rtld.path = xstrdup(obj_main->interp);
429 __progname = obj_rtld.path;
432 digest_dynamic(obj_main, 0);
434 linkmap_add(obj_main);
435 linkmap_add(&obj_rtld);
437 /* Link the main program into the list of objects. */
438 *obj_tail = obj_main;
439 obj_tail = &obj_main->next;
442 /* Make sure we don't call the main program's init and fini functions. */
443 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
445 /* Initialize a fake symbol for resolving undefined weak references. */
446 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
447 sym_zero.st_shndx = SHN_UNDEF;
450 libmap_disable = (bool)lm_init(libmap_override);
452 dbg("loading LD_PRELOAD libraries");
453 if (load_preload_objects() == -1)
455 preload_tail = obj_tail;
457 dbg("loading needed objects");
458 if (load_needed_objects(obj_main) == -1)
461 /* Make a list of all objects loaded at startup. */
462 for (obj = obj_list; obj != NULL; obj = obj->next) {
463 objlist_push_tail(&list_main, obj);
467 dbg("checking for required versions");
468 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
471 if (ld_tracing) { /* We're done */
472 trace_loaded_objects(obj_main);
476 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
477 dump_relocations(obj_main);
481 /* setup TLS for main thread */
482 dbg("initializing initial thread local storage");
483 STAILQ_FOREACH(entry, &list_main, link) {
485 * Allocate all the initial objects out of the static TLS
486 * block even if they didn't ask for it.
488 allocate_tls_offset(entry->obj);
490 allocate_initial_tls(obj_list);
492 if (relocate_objects(obj_main,
493 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld) == -1)
496 dbg("doing copy relocations");
497 if (do_copy_relocations(obj_main) == -1)
500 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
501 dump_relocations(obj_main);
505 dbg("initializing key program variables");
506 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
507 set_program_var("environ", env);
509 dbg("initializing thread locks");
512 /* Make a list of init functions to call. */
513 objlist_init(&initlist);
514 initlist_add_objects(obj_list, preload_tail, &initlist);
516 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
518 lockstate = wlock_acquire(rtld_bind_lock);
519 objlist_call_init(&initlist, &lockstate);
520 objlist_clear(&initlist);
521 wlock_release(rtld_bind_lock, lockstate);
523 dbg("transferring control to program entry point = %p", obj_main->entry);
525 /* Return the exit procedure and the program entry point. */
526 *exit_proc = rtld_exit;
528 return (func_ptr_type) obj_main->entry;
532 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
536 const Obj_Entry *defobj;
541 lockstate = rlock_acquire(rtld_bind_lock);
543 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
545 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
547 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
548 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL);
552 target = (Elf_Addr)(defobj->relocbase + def->st_value);
554 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
555 defobj->strtab + def->st_name, basename(obj->path),
556 (void *)target, basename(defobj->path));
559 * Write the new contents for the jmpslot. Note that depending on
560 * architecture, the value which we need to return back to the
561 * lazy binding trampoline may or may not be the target
562 * address. The value returned from reloc_jmpslot() is the value
563 * that the trampoline needs.
565 target = reloc_jmpslot(where, target, defobj, obj, rel);
566 rlock_release(rtld_bind_lock, lockstate);
571 * Error reporting function. Use it like printf. If formats the message
572 * into a buffer, and sets things up so that the next call to dlerror()
573 * will return the message.
576 _rtld_error(const char *fmt, ...)
578 static char buf[512];
582 vsnprintf(buf, sizeof buf, fmt, ap);
588 * Return a dynamically-allocated copy of the current error message, if any.
593 return error_message == NULL ? NULL : xstrdup(error_message);
597 * Restore the current error message from a copy which was previously saved
598 * by errmsg_save(). The copy is freed.
601 errmsg_restore(char *saved_msg)
603 if (saved_msg == NULL)
604 error_message = NULL;
606 _rtld_error("%s", saved_msg);
612 basename(const char *name)
614 const char *p = strrchr(name, '/');
615 return p != NULL ? p + 1 : name;
621 const char *msg = dlerror();
629 * Process a shared object's DYNAMIC section, and save the important
630 * information in its Obj_Entry structure.
633 digest_dynamic(Obj_Entry *obj, int early)
636 Needed_Entry **needed_tail = &obj->needed;
637 const Elf_Dyn *dyn_rpath = NULL;
638 const Elf_Dyn *dyn_soname = NULL;
639 int plttype = DT_REL;
641 obj->bind_now = false;
642 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
643 switch (dynp->d_tag) {
646 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
650 obj->relsize = dynp->d_un.d_val;
654 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
658 obj->pltrel = (const Elf_Rel *)
659 (obj->relocbase + dynp->d_un.d_ptr);
663 obj->pltrelsize = dynp->d_un.d_val;
667 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
671 obj->relasize = dynp->d_un.d_val;
675 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
679 plttype = dynp->d_un.d_val;
680 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
684 obj->symtab = (const Elf_Sym *)
685 (obj->relocbase + dynp->d_un.d_ptr);
689 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
693 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
697 obj->strsize = dynp->d_un.d_val;
701 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
706 obj->verneednum = dynp->d_un.d_val;
710 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
715 obj->verdefnum = dynp->d_un.d_val;
719 obj->versyms = (const Elf_Versym *)(obj->relocbase +
725 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
726 (obj->relocbase + dynp->d_un.d_ptr);
727 obj->nbuckets = hashtab[0];
728 obj->nchains = hashtab[1];
729 obj->buckets = hashtab + 2;
730 obj->chains = obj->buckets + obj->nbuckets;
736 Needed_Entry *nep = NEW(Needed_Entry);
737 nep->name = dynp->d_un.d_val;
742 needed_tail = &nep->next;
747 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
755 obj->symbolic = true;
759 case DT_RUNPATH: /* XXX: process separately */
761 * We have to wait until later to process this, because we
762 * might not have gotten the address of the string table yet.
772 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
776 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
780 /* XXX - not implemented yet */
782 dbg("Filling in DT_DEBUG entry");
783 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
787 if (dynp->d_un.d_val & DF_ORIGIN) {
788 obj->origin_path = xmalloc(PATH_MAX);
789 if (rtld_dirname(obj->path, obj->origin_path) == -1)
792 if (dynp->d_un.d_val & DF_SYMBOLIC)
793 obj->symbolic = true;
794 if (dynp->d_un.d_val & DF_TEXTREL)
796 if (dynp->d_un.d_val & DF_BIND_NOW)
797 obj->bind_now = true;
798 if (dynp->d_un.d_val & DF_STATIC_TLS)
804 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
813 if (plttype == DT_RELA) {
814 obj->pltrela = (const Elf_Rela *) obj->pltrel;
816 obj->pltrelasize = obj->pltrelsize;
820 if (dyn_rpath != NULL)
821 obj->rpath = obj->strtab + dyn_rpath->d_un.d_val;
823 if (dyn_soname != NULL)
824 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
828 * Process a shared object's program header. This is used only for the
829 * main program, when the kernel has already loaded the main program
830 * into memory before calling the dynamic linker. It creates and
831 * returns an Obj_Entry structure.
834 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
837 const Elf_Phdr *phlimit = phdr + phnum;
842 for (ph = phdr; ph < phlimit; ph++) {
843 switch (ph->p_type) {
846 if ((const Elf_Phdr *)ph->p_vaddr != phdr) {
847 _rtld_error("%s: invalid PT_PHDR", path);
850 obj->phdr = (const Elf_Phdr *) ph->p_vaddr;
851 obj->phsize = ph->p_memsz;
855 obj->interp = (const char *) ph->p_vaddr;
859 if (nsegs == 0) { /* First load segment */
860 obj->vaddrbase = trunc_page(ph->p_vaddr);
861 obj->mapbase = (caddr_t) obj->vaddrbase;
862 obj->relocbase = obj->mapbase - obj->vaddrbase;
863 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
865 } else { /* Last load segment */
866 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
873 obj->dynamic = (const Elf_Dyn *) ph->p_vaddr;
878 obj->tlssize = ph->p_memsz;
879 obj->tlsalign = ph->p_align;
880 obj->tlsinitsize = ph->p_filesz;
881 obj->tlsinit = (void*) ph->p_vaddr;
886 _rtld_error("%s: too few PT_LOAD segments", path);
895 dlcheck(void *handle)
899 for (obj = obj_list; obj != NULL; obj = obj->next)
900 if (obj == (Obj_Entry *) handle)
903 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
904 _rtld_error("Invalid shared object handle %p", handle);
911 * If the given object is already in the donelist, return true. Otherwise
912 * add the object to the list and return false.
915 donelist_check(DoneList *dlp, const Obj_Entry *obj)
919 for (i = 0; i < dlp->num_used; i++)
920 if (dlp->objs[i] == obj)
923 * Our donelist allocation should always be sufficient. But if
924 * our threads locking isn't working properly, more shared objects
925 * could have been loaded since we allocated the list. That should
926 * never happen, but we'll handle it properly just in case it does.
928 if (dlp->num_used < dlp->num_alloc)
929 dlp->objs[dlp->num_used++] = obj;
934 * Hash function for symbol table lookup. Don't even think about changing
935 * this. It is specified by the System V ABI.
938 elf_hash(const char *name)
940 const unsigned char *p = (const unsigned char *) name;
946 if ((g = h & 0xf0000000) != 0)
954 * Find the library with the given name, and return its full pathname.
955 * The returned string is dynamically allocated. Generates an error
956 * message and returns NULL if the library cannot be found.
958 * If the second argument is non-NULL, then it refers to an already-
959 * loaded shared object, whose library search path will be searched.
961 * The search order is:
963 * rpath in the referencing file
968 find_library(const char *xname, const Obj_Entry *refobj)
973 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
974 if (xname[0] != '/' && !trust) {
975 _rtld_error("Absolute pathname required for shared object \"%s\"",
979 return xstrdup(xname);
982 if (libmap_disable || (refobj == NULL) ||
983 (name = lm_find(refobj->path, xname)) == NULL)
984 name = (char *)xname;
986 dbg(" Searching for \"%s\"", name);
988 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
990 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
991 (pathname = search_library_path(name, gethints())) != NULL ||
992 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
995 if(refobj != NULL && refobj->path != NULL) {
996 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
997 name, basename(refobj->path));
999 _rtld_error("Shared object \"%s\" not found", name);
1005 * Given a symbol number in a referencing object, find the corresponding
1006 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1007 * no definition was found. Returns a pointer to the Obj_Entry of the
1008 * defining object via the reference parameter DEFOBJ_OUT.
1011 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1012 const Obj_Entry **defobj_out, int flags, SymCache *cache)
1016 const Obj_Entry *defobj;
1017 const Ver_Entry *ventry;
1022 * If we have already found this symbol, get the information from
1025 if (symnum >= refobj->nchains)
1026 return NULL; /* Bad object */
1027 if (cache != NULL && cache[symnum].sym != NULL) {
1028 *defobj_out = cache[symnum].obj;
1029 return cache[symnum].sym;
1032 ref = refobj->symtab + symnum;
1033 name = refobj->strtab + ref->st_name;
1037 * We don't have to do a full scale lookup if the symbol is local.
1038 * We know it will bind to the instance in this load module; to
1039 * which we already have a pointer (ie ref). By not doing a lookup,
1040 * we not only improve performance, but it also avoids unresolvable
1041 * symbols when local symbols are not in the hash table. This has
1042 * been seen with the ia64 toolchain.
1044 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1045 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1046 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1049 ventry = fetch_ventry(refobj, symnum);
1050 hash = elf_hash(name);
1051 def = symlook_default(name, hash, refobj, &defobj, ventry, flags);
1058 * If we found no definition and the reference is weak, treat the
1059 * symbol as having the value zero.
1061 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1067 *defobj_out = defobj;
1068 /* Record the information in the cache to avoid subsequent lookups. */
1069 if (cache != NULL) {
1070 cache[symnum].sym = def;
1071 cache[symnum].obj = defobj;
1074 if (refobj != &obj_rtld)
1075 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1081 * Return the search path from the ldconfig hints file, reading it if
1082 * necessary. Returns NULL if there are problems with the hints file,
1083 * or if the search path there is empty.
1090 if (hints == NULL) {
1092 struct elfhints_hdr hdr;
1095 /* Keep from trying again in case the hints file is bad. */
1098 if ((fd = open(_PATH_ELF_HINTS, O_RDONLY)) == -1)
1100 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1101 hdr.magic != ELFHINTS_MAGIC ||
1106 p = xmalloc(hdr.dirlistlen + 1);
1107 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1108 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) {
1116 return hints[0] != '\0' ? hints : NULL;
1120 init_dag(Obj_Entry *root)
1124 donelist_init(&donelist);
1125 init_dag1(root, root, &donelist);
1129 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp)
1131 const Needed_Entry *needed;
1133 if (donelist_check(dlp, obj))
1137 objlist_push_tail(&obj->dldags, root);
1138 objlist_push_tail(&root->dagmembers, obj);
1139 for (needed = obj->needed; needed != NULL; needed = needed->next)
1140 if (needed->obj != NULL)
1141 init_dag1(root, needed->obj, dlp);
1145 * Initialize the dynamic linker. The argument is the address at which
1146 * the dynamic linker has been mapped into memory. The primary task of
1147 * this function is to relocate the dynamic linker.
1150 init_rtld(caddr_t mapbase)
1152 Obj_Entry objtmp; /* Temporary rtld object */
1155 * Conjure up an Obj_Entry structure for the dynamic linker.
1157 * The "path" member can't be initialized yet because string constatns
1158 * cannot yet be acessed. Below we will set it correctly.
1160 memset(&objtmp, 0, sizeof(objtmp));
1163 objtmp.mapbase = mapbase;
1165 objtmp.relocbase = mapbase;
1167 if (RTLD_IS_DYNAMIC()) {
1168 objtmp.dynamic = rtld_dynamic(&objtmp);
1169 digest_dynamic(&objtmp, 1);
1170 assert(objtmp.needed == NULL);
1171 assert(!objtmp.textrel);
1174 * Temporarily put the dynamic linker entry into the object list, so
1175 * that symbols can be found.
1178 relocate_objects(&objtmp, true, &objtmp);
1181 /* Initialize the object list. */
1182 obj_tail = &obj_list;
1184 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1185 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1187 /* Replace the path with a dynamically allocated copy. */
1188 obj_rtld.path = xstrdup(PATH_RTLD);
1190 r_debug.r_brk = r_debug_state;
1191 r_debug.r_state = RT_CONSISTENT;
1195 * Add the init functions from a needed object list (and its recursive
1196 * needed objects) to "list". This is not used directly; it is a helper
1197 * function for initlist_add_objects(). The write lock must be held
1198 * when this function is called.
1201 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1203 /* Recursively process the successor needed objects. */
1204 if (needed->next != NULL)
1205 initlist_add_neededs(needed->next, list);
1207 /* Process the current needed object. */
1208 if (needed->obj != NULL)
1209 initlist_add_objects(needed->obj, &needed->obj->next, list);
1213 * Scan all of the DAGs rooted in the range of objects from "obj" to
1214 * "tail" and add their init functions to "list". This recurses over
1215 * the DAGs and ensure the proper init ordering such that each object's
1216 * needed libraries are initialized before the object itself. At the
1217 * same time, this function adds the objects to the global finalization
1218 * list "list_fini" in the opposite order. The write lock must be
1219 * held when this function is called.
1222 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1226 obj->init_done = true;
1228 /* Recursively process the successor objects. */
1229 if (&obj->next != tail)
1230 initlist_add_objects(obj->next, tail, list);
1232 /* Recursively process the needed objects. */
1233 if (obj->needed != NULL)
1234 initlist_add_neededs(obj->needed, list);
1236 /* Add the object to the init list. */
1237 if (obj->init != (Elf_Addr)NULL)
1238 objlist_push_tail(list, obj);
1240 /* Add the object to the global fini list in the reverse order. */
1241 if (obj->fini != (Elf_Addr)NULL)
1242 objlist_push_head(&list_fini, obj);
1246 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1250 is_exported(const Elf_Sym *def)
1253 const func_ptr_type *p;
1255 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value);
1256 for (p = exports; *p != NULL; p++)
1257 if (FPTR_TARGET(*p) == value)
1263 * Given a shared object, traverse its list of needed objects, and load
1264 * each of them. Returns 0 on success. Generates an error message and
1265 * returns -1 on failure.
1268 load_needed_objects(Obj_Entry *first)
1272 for (obj = first; obj != NULL; obj = obj->next) {
1273 Needed_Entry *needed;
1275 for (needed = obj->needed; needed != NULL; needed = needed->next) {
1276 needed->obj = load_object(obj->strtab + needed->name, obj);
1277 if (needed->obj == NULL && !ld_tracing)
1286 load_preload_objects(void)
1288 char *p = ld_preload;
1289 static const char delim[] = " \t:;";
1294 p += strspn(p, delim);
1295 while (*p != '\0') {
1296 size_t len = strcspn(p, delim);
1301 if (load_object(p, NULL) == NULL)
1302 return -1; /* XXX - cleanup */
1305 p += strspn(p, delim);
1307 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
1312 * Load a shared object into memory, if it is not already loaded.
1314 * Returns a pointer to the Obj_Entry for the object. Returns NULL
1318 load_object(const char *name, const Obj_Entry *refobj)
1325 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1326 if (object_match_name(obj, name))
1329 path = find_library(name, refobj);
1334 * If we didn't find a match by pathname, open the file and check
1335 * again by device and inode. This avoids false mismatches caused
1336 * by multiple links or ".." in pathnames.
1338 * To avoid a race, we open the file and use fstat() rather than
1341 if ((fd = open(path, O_RDONLY)) == -1) {
1342 _rtld_error("Cannot open \"%s\"", path);
1346 if (fstat(fd, &sb) == -1) {
1347 _rtld_error("Cannot fstat \"%s\"", path);
1352 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
1353 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) {
1359 object_add_name(obj, name);
1365 /* First use of this object, so we must map it in */
1366 obj = do_load_object(fd, name, path, &sb);
1375 do_load_object(int fd, const char *name, char *path, struct stat *sbp)
1381 * but first, make sure that environment variables haven't been
1382 * used to circumvent the noexec flag on a filesystem.
1384 if (dangerous_ld_env) {
1385 if (fstatfs(fd, &fs) != 0) {
1386 _rtld_error("Cannot fstatfs \"%s\"", path);
1389 if (fs.f_flags & MNT_NOEXEC) {
1390 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
1394 dbg("loading \"%s\"", path);
1395 obj = map_object(fd, path, sbp);
1399 object_add_name(obj, name);
1401 digest_dynamic(obj, 0);
1404 obj_tail = &obj->next;
1407 linkmap_add(obj); /* for GDB & dlinfo() */
1409 dbg(" %p .. %p: %s", obj->mapbase,
1410 obj->mapbase + obj->mapsize - 1, obj->path);
1412 dbg(" WARNING: %s has impure text", obj->path);
1413 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
1420 obj_from_addr(const void *addr)
1424 for (obj = obj_list; obj != NULL; obj = obj->next) {
1425 if (addr < (void *) obj->mapbase)
1427 if (addr < (void *) (obj->mapbase + obj->mapsize))
1434 * Call the finalization functions for each of the objects in "list"
1435 * which are unreferenced. All of the objects are expected to have
1436 * non-NULL fini functions.
1439 objlist_call_fini(Objlist *list, int *lockstate)
1445 * Preserve the current error message since a fini function might
1446 * call into the dynamic linker and overwrite it.
1448 saved_msg = errmsg_save();
1449 wlock_release(rtld_bind_lock, *lockstate);
1450 STAILQ_FOREACH(elm, list, link) {
1451 if (elm->obj->refcount == 0) {
1452 dbg("calling fini function for %s at %p", elm->obj->path,
1453 (void *)elm->obj->fini);
1454 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0,
1456 call_initfini_pointer(elm->obj, elm->obj->fini);
1459 *lockstate = wlock_acquire(rtld_bind_lock);
1460 errmsg_restore(saved_msg);
1464 * Call the initialization functions for each of the objects in
1465 * "list". All of the objects are expected to have non-NULL init
1469 objlist_call_init(Objlist *list, int *lockstate)
1475 * Preserve the current error message since an init function might
1476 * call into the dynamic linker and overwrite it.
1478 saved_msg = errmsg_save();
1479 wlock_release(rtld_bind_lock, *lockstate);
1480 STAILQ_FOREACH(elm, list, link) {
1481 dbg("calling init function for %s at %p", elm->obj->path,
1482 (void *)elm->obj->init);
1483 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0,
1485 call_initfini_pointer(elm->obj, elm->obj->init);
1487 *lockstate = wlock_acquire(rtld_bind_lock);
1488 errmsg_restore(saved_msg);
1492 objlist_clear(Objlist *list)
1496 while (!STAILQ_EMPTY(list)) {
1497 elm = STAILQ_FIRST(list);
1498 STAILQ_REMOVE_HEAD(list, link);
1503 static Objlist_Entry *
1504 objlist_find(Objlist *list, const Obj_Entry *obj)
1508 STAILQ_FOREACH(elm, list, link)
1509 if (elm->obj == obj)
1515 objlist_init(Objlist *list)
1521 objlist_push_head(Objlist *list, Obj_Entry *obj)
1525 elm = NEW(Objlist_Entry);
1527 STAILQ_INSERT_HEAD(list, elm, link);
1531 objlist_push_tail(Objlist *list, Obj_Entry *obj)
1535 elm = NEW(Objlist_Entry);
1537 STAILQ_INSERT_TAIL(list, elm, link);
1541 objlist_remove(Objlist *list, Obj_Entry *obj)
1545 if ((elm = objlist_find(list, obj)) != NULL) {
1546 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
1552 * Remove all of the unreferenced objects from "list".
1555 objlist_remove_unref(Objlist *list)
1560 STAILQ_INIT(&newlist);
1561 while (!STAILQ_EMPTY(list)) {
1562 elm = STAILQ_FIRST(list);
1563 STAILQ_REMOVE_HEAD(list, link);
1564 if (elm->obj->refcount == 0)
1567 STAILQ_INSERT_TAIL(&newlist, elm, link);
1573 * Relocate newly-loaded shared objects. The argument is a pointer to
1574 * the Obj_Entry for the first such object. All objects from the first
1575 * to the end of the list of objects are relocated. Returns 0 on success,
1579 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj)
1583 for (obj = first; obj != NULL; obj = obj->next) {
1585 dbg("relocating \"%s\"", obj->path);
1586 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL ||
1587 obj->symtab == NULL || obj->strtab == NULL) {
1588 _rtld_error("%s: Shared object has no run-time symbol table",
1594 /* There are relocations to the write-protected text segment. */
1595 if (mprotect(obj->mapbase, obj->textsize,
1596 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
1597 _rtld_error("%s: Cannot write-enable text segment: %s",
1598 obj->path, strerror(errno));
1603 /* Process the non-PLT relocations. */
1604 if (reloc_non_plt(obj, rtldobj))
1607 if (obj->textrel) { /* Re-protected the text segment. */
1608 if (mprotect(obj->mapbase, obj->textsize,
1609 PROT_READ|PROT_EXEC) == -1) {
1610 _rtld_error("%s: Cannot write-protect text segment: %s",
1611 obj->path, strerror(errno));
1616 /* Process the PLT relocations. */
1617 if (reloc_plt(obj) == -1)
1619 /* Relocate the jump slots if we are doing immediate binding. */
1620 if (obj->bind_now || bind_now)
1621 if (reloc_jmpslots(obj) == -1)
1626 * Set up the magic number and version in the Obj_Entry. These
1627 * were checked in the crt1.o from the original ElfKit, so we
1628 * set them for backward compatibility.
1630 obj->magic = RTLD_MAGIC;
1631 obj->version = RTLD_VERSION;
1633 /* Set the special PLT or GOT entries. */
1641 * Cleanup procedure. It will be called (by the atexit mechanism) just
1642 * before the process exits.
1650 lockstate = wlock_acquire(rtld_bind_lock);
1652 /* Clear all the reference counts so the fini functions will be called. */
1653 for (obj = obj_list; obj != NULL; obj = obj->next)
1655 objlist_call_fini(&list_fini, &lockstate);
1656 /* No need to remove the items from the list, since we are exiting. */
1657 if (!libmap_disable)
1659 wlock_release(rtld_bind_lock, lockstate);
1663 path_enumerate(const char *path, path_enum_proc callback, void *arg)
1671 path += strspn(path, ":;");
1672 while (*path != '\0') {
1676 len = strcspn(path, ":;");
1678 trans = lm_findn(NULL, path, len);
1680 res = callback(trans, strlen(trans), arg);
1683 res = callback(path, len, arg);
1689 path += strspn(path, ":;");
1695 struct try_library_args {
1703 try_library_path(const char *dir, size_t dirlen, void *param)
1705 struct try_library_args *arg;
1708 if (*dir == '/' || trust) {
1711 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
1714 pathname = arg->buffer;
1715 strncpy(pathname, dir, dirlen);
1716 pathname[dirlen] = '/';
1717 strcpy(pathname + dirlen + 1, arg->name);
1719 dbg(" Trying \"%s\"", pathname);
1720 if (access(pathname, F_OK) == 0) { /* We found it */
1721 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
1722 strcpy(pathname, arg->buffer);
1730 search_library_path(const char *name, const char *path)
1733 struct try_library_args arg;
1739 arg.namelen = strlen(name);
1740 arg.buffer = xmalloc(PATH_MAX);
1741 arg.buflen = PATH_MAX;
1743 p = path_enumerate(path, try_library_path, &arg);
1751 dlclose(void *handle)
1756 lockstate = wlock_acquire(rtld_bind_lock);
1757 root = dlcheck(handle);
1759 wlock_release(rtld_bind_lock, lockstate);
1762 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
1765 /* Unreference the object and its dependencies. */
1766 root->dl_refcount--;
1770 if (root->refcount == 0) {
1772 * The object is no longer referenced, so we must unload it.
1773 * First, call the fini functions.
1775 objlist_call_fini(&list_fini, &lockstate);
1776 objlist_remove_unref(&list_fini);
1778 /* Finish cleaning up the newly-unreferenced objects. */
1779 GDB_STATE(RT_DELETE,&root->linkmap);
1780 unload_object(root);
1781 GDB_STATE(RT_CONSISTENT,NULL);
1783 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
1784 wlock_release(rtld_bind_lock, lockstate);
1791 char *msg = error_message;
1792 error_message = NULL;
1797 * This function is deprecated and has no effect.
1800 dllockinit(void *context,
1801 void *(*lock_create)(void *context),
1802 void (*rlock_acquire)(void *lock),
1803 void (*wlock_acquire)(void *lock),
1804 void (*lock_release)(void *lock),
1805 void (*lock_destroy)(void *lock),
1806 void (*context_destroy)(void *context))
1808 static void *cur_context;
1809 static void (*cur_context_destroy)(void *);
1811 /* Just destroy the context from the previous call, if necessary. */
1812 if (cur_context_destroy != NULL)
1813 cur_context_destroy(cur_context);
1814 cur_context = context;
1815 cur_context_destroy = context_destroy;
1819 dlopen(const char *name, int mode)
1821 Obj_Entry **old_obj_tail;
1824 int result, lockstate;
1826 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
1827 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
1828 if (ld_tracing != NULL)
1829 environ = (char **)*get_program_var_addr("environ");
1831 objlist_init(&initlist);
1833 lockstate = wlock_acquire(rtld_bind_lock);
1834 GDB_STATE(RT_ADD,NULL);
1836 old_obj_tail = obj_tail;
1842 obj = load_object(name, obj_main);
1847 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
1848 objlist_push_tail(&list_global, obj);
1849 mode &= RTLD_MODEMASK;
1850 if (*old_obj_tail != NULL) { /* We loaded something new. */
1851 assert(*old_obj_tail == obj);
1852 result = load_needed_objects(obj);
1855 result = rtld_verify_versions(&obj->dagmembers);
1856 if (result != -1 && ld_tracing)
1859 (relocate_objects(obj, mode == RTLD_NOW, &obj_rtld)) == -1) {
1862 if (obj->refcount == 0)
1866 /* Make list of init functions to call. */
1867 initlist_add_objects(obj, &obj->next, &initlist);
1871 /* Bump the reference counts for objects on this DAG. */
1879 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
1881 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
1883 /* Call the init functions. */
1884 objlist_call_init(&initlist, &lockstate);
1885 objlist_clear(&initlist);
1886 wlock_release(rtld_bind_lock, lockstate);
1889 trace_loaded_objects(obj);
1890 wlock_release(rtld_bind_lock, lockstate);
1895 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
1899 const Obj_Entry *obj, *defobj;
1900 const Elf_Sym *def, *symp;
1904 hash = elf_hash(name);
1907 flags |= SYMLOOK_IN_PLT;
1909 lockstate = rlock_acquire(rtld_bind_lock);
1910 if (handle == NULL || handle == RTLD_NEXT ||
1911 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
1913 if ((obj = obj_from_addr(retaddr)) == NULL) {
1914 _rtld_error("Cannot determine caller's shared object");
1915 rlock_release(rtld_bind_lock, lockstate);
1918 if (handle == NULL) { /* Just the caller's shared object. */
1919 def = symlook_obj(name, hash, obj, ve, flags);
1921 } else if (handle == RTLD_NEXT || /* Objects after caller's */
1922 handle == RTLD_SELF) { /* ... caller included */
1923 if (handle == RTLD_NEXT)
1925 for (; obj != NULL; obj = obj->next) {
1926 if ((symp = symlook_obj(name, hash, obj, ve, flags)) != NULL) {
1927 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) {
1930 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
1936 * Search the dynamic linker itself, and possibly resolve the
1937 * symbol from there. This is how the application links to
1938 * dynamic linker services such as dlopen. Only the values listed
1939 * in the "exports" array can be resolved from the dynamic linker.
1941 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
1942 symp = symlook_obj(name, hash, &obj_rtld, ve, flags);
1943 if (symp != NULL && is_exported(symp)) {
1949 assert(handle == RTLD_DEFAULT);
1950 def = symlook_default(name, hash, obj, &defobj, ve, flags);
1953 if ((obj = dlcheck(handle)) == NULL) {
1954 rlock_release(rtld_bind_lock, lockstate);
1958 donelist_init(&donelist);
1959 if (obj->mainprog) {
1960 /* Search main program and all libraries loaded by it. */
1961 def = symlook_list(name, hash, &list_main, &defobj, ve, flags,
1966 /* Search the whole DAG rooted at the given object. */
1968 fake.obj = (Obj_Entry *)obj;
1970 def = symlook_needed(name, hash, &fake, &defobj, ve, flags,
1976 rlock_release(rtld_bind_lock, lockstate);
1979 * The value required by the caller is derived from the value
1980 * of the symbol. For the ia64 architecture, we need to
1981 * construct a function descriptor which the caller can use to
1982 * call the function with the right 'gp' value. For other
1983 * architectures and for non-functions, the value is simply
1984 * the relocated value of the symbol.
1986 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
1987 return make_function_pointer(def, defobj);
1989 return defobj->relocbase + def->st_value;
1992 _rtld_error("Undefined symbol \"%s\"", name);
1993 rlock_release(rtld_bind_lock, lockstate);
1998 dlsym(void *handle, const char *name)
2000 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
2005 dlvsym(void *handle, const char *name, const char *version)
2009 ventry.name = version;
2011 ventry.hash = elf_hash(version);
2013 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
2018 dladdr(const void *addr, Dl_info *info)
2020 const Obj_Entry *obj;
2023 unsigned long symoffset;
2026 lockstate = rlock_acquire(rtld_bind_lock);
2027 obj = obj_from_addr(addr);
2029 _rtld_error("No shared object contains address");
2030 rlock_release(rtld_bind_lock, lockstate);
2033 info->dli_fname = obj->path;
2034 info->dli_fbase = obj->mapbase;
2035 info->dli_saddr = (void *)0;
2036 info->dli_sname = NULL;
2039 * Walk the symbol list looking for the symbol whose address is
2040 * closest to the address sent in.
2042 for (symoffset = 0; symoffset < obj->nchains; symoffset++) {
2043 def = obj->symtab + symoffset;
2046 * For skip the symbol if st_shndx is either SHN_UNDEF or
2049 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
2053 * If the symbol is greater than the specified address, or if it
2054 * is further away from addr than the current nearest symbol,
2057 symbol_addr = obj->relocbase + def->st_value;
2058 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
2061 /* Update our idea of the nearest symbol. */
2062 info->dli_sname = obj->strtab + def->st_name;
2063 info->dli_saddr = symbol_addr;
2066 if (info->dli_saddr == addr)
2069 rlock_release(rtld_bind_lock, lockstate);
2074 dlinfo(void *handle, int request, void *p)
2076 const Obj_Entry *obj;
2077 int error, lockstate;
2079 lockstate = rlock_acquire(rtld_bind_lock);
2081 if (handle == NULL || handle == RTLD_SELF) {
2084 retaddr = __builtin_return_address(0); /* __GNUC__ only */
2085 if ((obj = obj_from_addr(retaddr)) == NULL)
2086 _rtld_error("Cannot determine caller's shared object");
2088 obj = dlcheck(handle);
2091 rlock_release(rtld_bind_lock, lockstate);
2097 case RTLD_DI_LINKMAP:
2098 *((struct link_map const **)p) = &obj->linkmap;
2100 case RTLD_DI_ORIGIN:
2101 error = rtld_dirname(obj->path, p);
2104 case RTLD_DI_SERINFOSIZE:
2105 case RTLD_DI_SERINFO:
2106 error = do_search_info(obj, request, (struct dl_serinfo *)p);
2110 _rtld_error("Invalid request %d passed to dlinfo()", request);
2114 rlock_release(rtld_bind_lock, lockstate);
2120 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
2122 struct dl_phdr_info phdr_info;
2123 const Obj_Entry *obj;
2124 int error, bind_lockstate, phdr_lockstate;
2126 phdr_lockstate = wlock_acquire(rtld_phdr_lock);
2127 bind_lockstate = rlock_acquire(rtld_bind_lock);
2131 for (obj = obj_list; obj != NULL; obj = obj->next) {
2132 phdr_info.dlpi_addr = (Elf_Addr)obj->relocbase;
2133 phdr_info.dlpi_name = STAILQ_FIRST(&obj->names) ?
2134 STAILQ_FIRST(&obj->names)->name : obj->path;
2135 phdr_info.dlpi_phdr = obj->phdr;
2136 phdr_info.dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
2137 phdr_info.dlpi_tls_modid = obj->tlsindex;
2138 phdr_info.dlpi_tls_data = obj->tlsinit;
2139 phdr_info.dlpi_adds = obj_loads;
2140 phdr_info.dlpi_subs = obj_loads - obj_count;
2142 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
2146 rlock_release(rtld_bind_lock, bind_lockstate);
2147 wlock_release(rtld_phdr_lock, phdr_lockstate);
2152 struct fill_search_info_args {
2155 Dl_serinfo *serinfo;
2156 Dl_serpath *serpath;
2161 fill_search_info(const char *dir, size_t dirlen, void *param)
2163 struct fill_search_info_args *arg;
2167 if (arg->request == RTLD_DI_SERINFOSIZE) {
2168 arg->serinfo->dls_cnt ++;
2169 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1;
2171 struct dl_serpath *s_entry;
2173 s_entry = arg->serpath;
2174 s_entry->dls_name = arg->strspace;
2175 s_entry->dls_flags = arg->flags;
2177 strncpy(arg->strspace, dir, dirlen);
2178 arg->strspace[dirlen] = '\0';
2180 arg->strspace += dirlen + 1;
2188 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
2190 struct dl_serinfo _info;
2191 struct fill_search_info_args args;
2193 args.request = RTLD_DI_SERINFOSIZE;
2194 args.serinfo = &_info;
2196 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2199 path_enumerate(ld_library_path, fill_search_info, &args);
2200 path_enumerate(obj->rpath, fill_search_info, &args);
2201 path_enumerate(gethints(), fill_search_info, &args);
2202 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
2205 if (request == RTLD_DI_SERINFOSIZE) {
2206 info->dls_size = _info.dls_size;
2207 info->dls_cnt = _info.dls_cnt;
2211 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
2212 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
2216 args.request = RTLD_DI_SERINFO;
2217 args.serinfo = info;
2218 args.serpath = &info->dls_serpath[0];
2219 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
2221 args.flags = LA_SER_LIBPATH;
2222 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
2225 args.flags = LA_SER_RUNPATH;
2226 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
2229 args.flags = LA_SER_CONFIG;
2230 if (path_enumerate(gethints(), fill_search_info, &args) != NULL)
2233 args.flags = LA_SER_DEFAULT;
2234 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
2240 rtld_dirname(const char *path, char *bname)
2244 /* Empty or NULL string gets treated as "." */
2245 if (path == NULL || *path == '\0') {
2251 /* Strip trailing slashes */
2252 endp = path + strlen(path) - 1;
2253 while (endp > path && *endp == '/')
2256 /* Find the start of the dir */
2257 while (endp > path && *endp != '/')
2260 /* Either the dir is "/" or there are no slashes */
2262 bname[0] = *endp == '/' ? '/' : '.';
2268 } while (endp > path && *endp == '/');
2271 if (endp - path + 2 > PATH_MAX)
2273 _rtld_error("Filename is too long: %s", path);
2277 strncpy(bname, path, endp - path + 1);
2278 bname[endp - path + 1] = '\0';
2283 linkmap_add(Obj_Entry *obj)
2285 struct link_map *l = &obj->linkmap;
2286 struct link_map *prev;
2288 obj->linkmap.l_name = obj->path;
2289 obj->linkmap.l_addr = obj->mapbase;
2290 obj->linkmap.l_ld = obj->dynamic;
2292 /* GDB needs load offset on MIPS to use the symbols */
2293 obj->linkmap.l_offs = obj->relocbase;
2296 if (r_debug.r_map == NULL) {
2302 * Scan to the end of the list, but not past the entry for the
2303 * dynamic linker, which we want to keep at the very end.
2305 for (prev = r_debug.r_map;
2306 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
2307 prev = prev->l_next)
2310 /* Link in the new entry. */
2312 l->l_next = prev->l_next;
2313 if (l->l_next != NULL)
2314 l->l_next->l_prev = l;
2319 linkmap_delete(Obj_Entry *obj)
2321 struct link_map *l = &obj->linkmap;
2323 if (l->l_prev == NULL) {
2324 if ((r_debug.r_map = l->l_next) != NULL)
2325 l->l_next->l_prev = NULL;
2329 if ((l->l_prev->l_next = l->l_next) != NULL)
2330 l->l_next->l_prev = l->l_prev;
2334 * Function for the debugger to set a breakpoint on to gain control.
2336 * The two parameters allow the debugger to easily find and determine
2337 * what the runtime loader is doing and to whom it is doing it.
2339 * When the loadhook trap is hit (r_debug_state, set at program
2340 * initialization), the arguments can be found on the stack:
2342 * +8 struct link_map *m
2343 * +4 struct r_debug *rd
2347 r_debug_state(struct r_debug* rd, struct link_map *m)
2352 * Get address of the pointer variable in the main program.
2354 static const void **
2355 get_program_var_addr(const char *name)
2357 const Obj_Entry *obj;
2360 hash = elf_hash(name);
2361 for (obj = obj_main; obj != NULL; obj = obj->next) {
2364 if ((def = symlook_obj(name, hash, obj, NULL, 0)) != NULL) {
2367 addr = (const void **)(obj->relocbase + def->st_value);
2375 * Set a pointer variable in the main program to the given value. This
2376 * is used to set key variables such as "environ" before any of the
2377 * init functions are called.
2380 set_program_var(const char *name, const void *value)
2384 if ((addr = get_program_var_addr(name)) != NULL) {
2385 dbg("\"%s\": *%p <-- %p", name, addr, value);
2391 * Given a symbol name in a referencing object, find the corresponding
2392 * definition of the symbol. Returns a pointer to the symbol, or NULL if
2393 * no definition was found. Returns a pointer to the Obj_Entry of the
2394 * defining object via the reference parameter DEFOBJ_OUT.
2396 static const Elf_Sym *
2397 symlook_default(const char *name, unsigned long hash, const Obj_Entry *refobj,
2398 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags)
2402 const Elf_Sym *symp;
2403 const Obj_Entry *obj;
2404 const Obj_Entry *defobj;
2405 const Objlist_Entry *elm;
2408 donelist_init(&donelist);
2410 /* Look first in the referencing object if linked symbolically. */
2411 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
2412 symp = symlook_obj(name, hash, refobj, ventry, flags);
2419 /* Search all objects loaded at program start up. */
2420 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2421 symp = symlook_list(name, hash, &list_main, &obj, ventry, flags,
2424 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
2430 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
2431 STAILQ_FOREACH(elm, &list_global, link) {
2432 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK)
2434 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry,
2437 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
2443 /* Search all dlopened DAGs containing the referencing object. */
2444 STAILQ_FOREACH(elm, &refobj->dldags, link) {
2445 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK)
2447 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry,
2450 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
2457 * Search the dynamic linker itself, and possibly resolve the
2458 * symbol from there. This is how the application links to
2459 * dynamic linker services such as dlopen. Only the values listed
2460 * in the "exports" array can be resolved from the dynamic linker.
2462 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2463 symp = symlook_obj(name, hash, &obj_rtld, ventry, flags);
2464 if (symp != NULL && is_exported(symp)) {
2471 *defobj_out = defobj;
2475 static const Elf_Sym *
2476 symlook_list(const char *name, unsigned long hash, const Objlist *objlist,
2477 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags,
2480 const Elf_Sym *symp;
2482 const Obj_Entry *defobj;
2483 const Objlist_Entry *elm;
2487 STAILQ_FOREACH(elm, objlist, link) {
2488 if (donelist_check(dlp, elm->obj))
2490 if ((symp = symlook_obj(name, hash, elm->obj, ventry, flags)) != NULL) {
2491 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) {
2494 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
2500 *defobj_out = defobj;
2505 * Search the symbol table of a shared object and all objects needed
2506 * by it for a symbol of the given name. Search order is
2507 * breadth-first. Returns a pointer to the symbol, or NULL if no
2508 * definition was found.
2510 static const Elf_Sym *
2511 symlook_needed(const char *name, unsigned long hash, const Needed_Entry *needed,
2512 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags,
2515 const Elf_Sym *def, *def_w;
2516 const Needed_Entry *n;
2517 const Obj_Entry *obj, *defobj, *defobj1;
2521 for (n = needed; n != NULL; n = n->next) {
2522 if ((obj = n->obj) == NULL ||
2523 donelist_check(dlp, obj) ||
2524 (def = symlook_obj(name, hash, obj, ventry, flags)) == NULL)
2527 if (ELF_ST_BIND(def->st_info) != STB_WEAK) {
2528 *defobj_out = defobj;
2533 * There we come when either symbol definition is not found in
2534 * directly needed objects, or found symbol is weak.
2536 for (n = needed; n != NULL; n = n->next) {
2537 if ((obj = n->obj) == NULL)
2539 def_w = symlook_needed(name, hash, obj->needed, &defobj1,
2540 ventry, flags, dlp);
2543 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) {
2547 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK)
2551 *defobj_out = defobj;
2556 * Search the symbol table of a single shared object for a symbol of
2557 * the given name and version, if requested. Returns a pointer to the
2558 * symbol, or NULL if no definition was found.
2560 * The symbol's hash value is passed in for efficiency reasons; that
2561 * eliminates many recomputations of the hash value.
2564 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj,
2565 const Ver_Entry *ventry, int flags)
2567 unsigned long symnum;
2568 const Elf_Sym *vsymp;
2572 if (obj->buckets == NULL)
2577 symnum = obj->buckets[hash % obj->nbuckets];
2579 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
2580 const Elf_Sym *symp;
2583 if (symnum >= obj->nchains)
2584 return NULL; /* Bad object */
2586 symp = obj->symtab + symnum;
2587 strp = obj->strtab + symp->st_name;
2589 switch (ELF_ST_TYPE(symp->st_info)) {
2593 if (symp->st_value == 0)
2597 if (symp->st_shndx != SHN_UNDEF ||
2598 ((flags & SYMLOOK_IN_PLT) == 0 &&
2599 ELF_ST_TYPE(symp->st_info) == STT_FUNC))
2605 if (name[0] != strp[0] || strcmp(name, strp) != 0)
2608 if (ventry == NULL) {
2609 if (obj->versyms != NULL) {
2610 verndx = VER_NDX(obj->versyms[symnum]);
2611 if (verndx > obj->vernum) {
2612 _rtld_error("%s: symbol %s references wrong version %d",
2613 obj->path, obj->strtab + symnum, verndx);
2617 * If we are not called from dlsym (i.e. this is a normal
2618 * relocation from unversioned binary, accept the symbol
2619 * immediately if it happens to have first version after
2620 * this shared object became versioned. Otherwise, if
2621 * symbol is versioned and not hidden, remember it. If it
2622 * is the only symbol with this name exported by the
2623 * shared object, it will be returned as a match at the
2624 * end of the function. If symbol is global (verndx < 2)
2625 * accept it unconditionally.
2627 if ((flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN)
2629 else if (verndx >= VER_NDX_GIVEN) {
2630 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) {
2640 if (obj->versyms == NULL) {
2641 if (object_match_name(obj, ventry->name)) {
2642 _rtld_error("%s: object %s should provide version %s for "
2643 "symbol %s", obj_rtld.path, obj->path, ventry->name,
2644 obj->strtab + symnum);
2648 verndx = VER_NDX(obj->versyms[symnum]);
2649 if (verndx > obj->vernum) {
2650 _rtld_error("%s: symbol %s references wrong version %d",
2651 obj->path, obj->strtab + symnum, verndx);
2654 if (obj->vertab[verndx].hash != ventry->hash ||
2655 strcmp(obj->vertab[verndx].name, ventry->name)) {
2657 * Version does not match. Look if this is a global symbol
2658 * and if it is not hidden. If global symbol (verndx < 2)
2659 * is available, use it. Do not return symbol if we are
2660 * called by dlvsym, because dlvsym looks for a specific
2661 * version and default one is not what dlvsym wants.
2663 if ((flags & SYMLOOK_DLSYM) ||
2664 (obj->versyms[symnum] & VER_NDX_HIDDEN) ||
2665 (verndx >= VER_NDX_GIVEN))
2672 return (vcount == 1) ? vsymp : NULL;
2676 trace_loaded_objects(Obj_Entry *obj)
2678 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
2681 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
2684 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
2685 fmt1 = "\t%o => %p (%x)\n";
2687 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
2688 fmt2 = "\t%o (%x)\n";
2690 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
2692 for (; obj; obj = obj->next) {
2693 Needed_Entry *needed;
2697 if (list_containers && obj->needed != NULL)
2698 printf("%s:\n", obj->path);
2699 for (needed = obj->needed; needed; needed = needed->next) {
2700 if (needed->obj != NULL) {
2701 if (needed->obj->traced && !list_containers)
2703 needed->obj->traced = true;
2704 path = needed->obj->path;
2708 name = (char *)obj->strtab + needed->name;
2709 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
2711 fmt = is_lib ? fmt1 : fmt2;
2712 while ((c = *fmt++) != '\0') {
2738 printf("%s", main_local);
2741 printf("%s", obj_main->path);
2748 printf("%d", sodp->sod_major);
2751 printf("%d", sodp->sod_minor);
2758 printf("%p", needed->obj ? needed->obj->mapbase : 0);
2770 * Unload a dlopened object and its dependencies from memory and from
2771 * our data structures. It is assumed that the DAG rooted in the
2772 * object has already been unreferenced, and that the object has a
2773 * reference count of 0.
2776 unload_object(Obj_Entry *root)
2781 assert(root->refcount == 0);
2784 * Pass over the DAG removing unreferenced objects from
2785 * appropriate lists.
2787 unlink_object(root);
2789 /* Unmap all objects that are no longer referenced. */
2790 linkp = &obj_list->next;
2791 while ((obj = *linkp) != NULL) {
2792 if (obj->refcount == 0) {
2793 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2795 dbg("unloading \"%s\"", obj->path);
2796 munmap(obj->mapbase, obj->mapsize);
2797 linkmap_delete(obj);
2808 unlink_object(Obj_Entry *root)
2812 if (root->refcount == 0) {
2813 /* Remove the object from the RTLD_GLOBAL list. */
2814 objlist_remove(&list_global, root);
2816 /* Remove the object from all objects' DAG lists. */
2817 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2818 objlist_remove(&elm->obj->dldags, root);
2819 if (elm->obj != root)
2820 unlink_object(elm->obj);
2826 ref_dag(Obj_Entry *root)
2830 STAILQ_FOREACH(elm, &root->dagmembers, link)
2831 elm->obj->refcount++;
2835 unref_dag(Obj_Entry *root)
2839 STAILQ_FOREACH(elm, &root->dagmembers, link)
2840 elm->obj->refcount--;
2844 * Common code for MD __tls_get_addr().
2847 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset)
2849 Elf_Addr* dtv = *dtvp;
2852 /* Check dtv generation in case new modules have arrived */
2853 if (dtv[0] != tls_dtv_generation) {
2857 lockstate = wlock_acquire(rtld_bind_lock);
2858 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
2860 if (to_copy > tls_max_index)
2861 to_copy = tls_max_index;
2862 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
2863 newdtv[0] = tls_dtv_generation;
2864 newdtv[1] = tls_max_index;
2866 wlock_release(rtld_bind_lock, lockstate);
2870 /* Dynamically allocate module TLS if necessary */
2871 if (!dtv[index + 1]) {
2872 /* Signal safe, wlock will block out signals. */
2873 lockstate = wlock_acquire(rtld_bind_lock);
2874 if (!dtv[index + 1])
2875 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
2876 wlock_release(rtld_bind_lock, lockstate);
2878 return (void*) (dtv[index + 1] + offset);
2881 /* XXX not sure what variants to use for arm. */
2883 #if defined(__ia64__) || defined(__powerpc__)
2886 * Allocate Static TLS using the Variant I method.
2889 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
2898 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
2901 assert(tcbsize >= TLS_TCB_SIZE);
2902 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
2903 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
2905 if (oldtcb != NULL) {
2906 memcpy(tls, oldtcb, tls_static_space);
2909 /* Adjust the DTV. */
2911 for (i = 0; i < dtv[1]; i++) {
2912 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
2913 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
2914 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
2918 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr));
2920 dtv[0] = tls_dtv_generation;
2921 dtv[1] = tls_max_index;
2923 for (obj = objs; obj; obj = obj->next) {
2924 if (obj->tlsoffset) {
2925 addr = (Elf_Addr)tls + obj->tlsoffset;
2926 memset((void*) (addr + obj->tlsinitsize),
2927 0, obj->tlssize - obj->tlsinitsize);
2929 memcpy((void*) addr, obj->tlsinit,
2931 dtv[obj->tlsindex + 1] = addr;
2940 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
2943 Elf_Addr tlsstart, tlsend;
2946 assert(tcbsize >= TLS_TCB_SIZE);
2948 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
2949 tlsend = tlsstart + tls_static_space;
2951 dtv = *(Elf_Addr **)tlsstart;
2953 for (i = 0; i < dtvsize; i++) {
2954 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
2955 free((void*)dtv[i+2]);
2964 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \
2968 * Allocate Static TLS using the Variant II method.
2971 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
2976 Elf_Addr *dtv, *olddtv;
2977 Elf_Addr segbase, oldsegbase, addr;
2980 size = round(tls_static_space, tcbalign);
2982 assert(tcbsize >= 2*sizeof(Elf_Addr));
2983 tls = calloc(1, size + tcbsize);
2984 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
2986 segbase = (Elf_Addr)(tls + size);
2987 ((Elf_Addr*)segbase)[0] = segbase;
2988 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
2990 dtv[0] = tls_dtv_generation;
2991 dtv[1] = tls_max_index;
2995 * Copy the static TLS block over whole.
2997 oldsegbase = (Elf_Addr) oldtls;
2998 memcpy((void *)(segbase - tls_static_space),
2999 (const void *)(oldsegbase - tls_static_space),
3003 * If any dynamic TLS blocks have been created tls_get_addr(),
3006 olddtv = ((Elf_Addr**)oldsegbase)[1];
3007 for (i = 0; i < olddtv[1]; i++) {
3008 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
3009 dtv[i+2] = olddtv[i+2];
3015 * We assume that this block was the one we created with
3016 * allocate_initial_tls().
3018 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
3020 for (obj = objs; obj; obj = obj->next) {
3021 if (obj->tlsoffset) {
3022 addr = segbase - obj->tlsoffset;
3023 memset((void*) (addr + obj->tlsinitsize),
3024 0, obj->tlssize - obj->tlsinitsize);
3026 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
3027 dtv[obj->tlsindex + 1] = addr;
3032 return (void*) segbase;
3036 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
3041 Elf_Addr tlsstart, tlsend;
3044 * Figure out the size of the initial TLS block so that we can
3045 * find stuff which ___tls_get_addr() allocated dynamically.
3047 size = round(tls_static_space, tcbalign);
3049 dtv = ((Elf_Addr**)tls)[1];
3051 tlsend = (Elf_Addr) tls;
3052 tlsstart = tlsend - size;
3053 for (i = 0; i < dtvsize; i++) {
3054 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) {
3055 free((void*) dtv[i+2]);
3059 free((void*) tlsstart);
3066 * Allocate TLS block for module with given index.
3069 allocate_module_tls(int index)
3074 for (obj = obj_list; obj; obj = obj->next) {
3075 if (obj->tlsindex == index)
3079 _rtld_error("Can't find module with TLS index %d", index);
3083 p = malloc(obj->tlssize);
3084 memcpy(p, obj->tlsinit, obj->tlsinitsize);
3085 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
3091 allocate_tls_offset(Obj_Entry *obj)
3098 if (obj->tlssize == 0) {
3099 obj->tls_done = true;
3103 if (obj->tlsindex == 1)
3104 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
3106 off = calculate_tls_offset(tls_last_offset, tls_last_size,
3107 obj->tlssize, obj->tlsalign);
3110 * If we have already fixed the size of the static TLS block, we
3111 * must stay within that size. When allocating the static TLS, we
3112 * leave a small amount of space spare to be used for dynamically
3113 * loading modules which use static TLS.
3115 if (tls_static_space) {
3116 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
3120 tls_last_offset = obj->tlsoffset = off;
3121 tls_last_size = obj->tlssize;
3122 obj->tls_done = true;
3128 free_tls_offset(Obj_Entry *obj)
3130 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \
3133 * If we were the last thing to allocate out of the static TLS
3134 * block, we give our space back to the 'allocator'. This is a
3135 * simplistic workaround to allow libGL.so.1 to be loaded and
3136 * unloaded multiple times. We only handle the Variant II
3137 * mechanism for now - this really needs a proper allocator.
3139 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
3140 == calculate_tls_end(tls_last_offset, tls_last_size)) {
3141 tls_last_offset -= obj->tlssize;
3148 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
3153 lockstate = wlock_acquire(rtld_bind_lock);
3154 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
3155 wlock_release(rtld_bind_lock, lockstate);
3160 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
3164 lockstate = wlock_acquire(rtld_bind_lock);
3165 free_tls(tcb, tcbsize, tcbalign);
3166 wlock_release(rtld_bind_lock, lockstate);
3170 object_add_name(Obj_Entry *obj, const char *name)
3176 entry = malloc(sizeof(Name_Entry) + len);
3178 if (entry != NULL) {
3179 strcpy(entry->name, name);
3180 STAILQ_INSERT_TAIL(&obj->names, entry, link);
3185 object_match_name(const Obj_Entry *obj, const char *name)
3189 STAILQ_FOREACH(entry, &obj->names, link) {
3190 if (strcmp(name, entry->name) == 0)
3197 locate_dependency(const Obj_Entry *obj, const char *name)
3199 const Objlist_Entry *entry;
3200 const Needed_Entry *needed;
3202 STAILQ_FOREACH(entry, &list_main, link) {
3203 if (object_match_name(entry->obj, name))
3207 for (needed = obj->needed; needed != NULL; needed = needed->next) {
3208 if (needed->obj == NULL)
3210 if (object_match_name(needed->obj, name))
3213 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
3219 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
3220 const Elf_Vernaux *vna)
3222 const Elf_Verdef *vd;
3223 const char *vername;
3225 vername = refobj->strtab + vna->vna_name;
3226 vd = depobj->verdef;
3228 _rtld_error("%s: version %s required by %s not defined",
3229 depobj->path, vername, refobj->path);
3233 if (vd->vd_version != VER_DEF_CURRENT) {
3234 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
3235 depobj->path, vd->vd_version);
3238 if (vna->vna_hash == vd->vd_hash) {
3239 const Elf_Verdaux *aux = (const Elf_Verdaux *)
3240 ((char *)vd + vd->vd_aux);
3241 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
3244 if (vd->vd_next == 0)
3246 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3248 if (vna->vna_flags & VER_FLG_WEAK)
3250 _rtld_error("%s: version %s required by %s not found",
3251 depobj->path, vername, refobj->path);
3256 rtld_verify_object_versions(Obj_Entry *obj)
3258 const Elf_Verneed *vn;
3259 const Elf_Verdef *vd;
3260 const Elf_Verdaux *vda;
3261 const Elf_Vernaux *vna;
3262 const Obj_Entry *depobj;
3263 int maxvernum, vernum;
3267 * Walk over defined and required version records and figure out
3268 * max index used by any of them. Do very basic sanity checking
3272 while (vn != NULL) {
3273 if (vn->vn_version != VER_NEED_CURRENT) {
3274 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
3275 obj->path, vn->vn_version);
3278 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
3280 vernum = VER_NEED_IDX(vna->vna_other);
3281 if (vernum > maxvernum)
3283 if (vna->vna_next == 0)
3285 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
3287 if (vn->vn_next == 0)
3289 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
3293 while (vd != NULL) {
3294 if (vd->vd_version != VER_DEF_CURRENT) {
3295 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
3296 obj->path, vd->vd_version);
3299 vernum = VER_DEF_IDX(vd->vd_ndx);
3300 if (vernum > maxvernum)
3302 if (vd->vd_next == 0)
3304 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3311 * Store version information in array indexable by version index.
3312 * Verify that object version requirements are satisfied along the
3315 obj->vernum = maxvernum + 1;
3316 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry));
3319 while (vd != NULL) {
3320 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
3321 vernum = VER_DEF_IDX(vd->vd_ndx);
3322 assert(vernum <= maxvernum);
3323 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
3324 obj->vertab[vernum].hash = vd->vd_hash;
3325 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
3326 obj->vertab[vernum].file = NULL;
3327 obj->vertab[vernum].flags = 0;
3329 if (vd->vd_next == 0)
3331 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3335 while (vn != NULL) {
3336 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
3337 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
3339 if (check_object_provided_version(obj, depobj, vna))
3341 vernum = VER_NEED_IDX(vna->vna_other);
3342 assert(vernum <= maxvernum);
3343 obj->vertab[vernum].hash = vna->vna_hash;
3344 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
3345 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
3346 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
3347 VER_INFO_HIDDEN : 0;
3348 if (vna->vna_next == 0)
3350 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
3352 if (vn->vn_next == 0)
3354 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
3360 rtld_verify_versions(const Objlist *objlist)
3362 Objlist_Entry *entry;
3366 STAILQ_FOREACH(entry, objlist, link) {
3368 * Skip dummy objects or objects that have their version requirements
3371 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
3373 if (rtld_verify_object_versions(entry->obj) == -1) {
3375 if (ld_tracing == NULL)
3379 if (rc == 0 || ld_tracing != NULL)
3380 rc = rtld_verify_object_versions(&obj_rtld);
3385 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
3390 vernum = VER_NDX(obj->versyms[symnum]);
3391 if (vernum >= obj->vernum) {
3392 _rtld_error("%s: symbol %s has wrong verneed value %d",
3393 obj->path, obj->strtab + symnum, vernum);
3394 } else if (obj->vertab[vernum].hash != 0) {
3395 return &obj->vertab[vernum];