2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * Copyright 2009, 2010, 2011 Konstantin Belousov <kib@FreeBSD.ORG>.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 * Dynamic linker for ELF.
33 * John Polstra <jdp@polstra.com>.
37 #error "GCC is needed to compile this file"
40 #include <sys/param.h>
41 #include <sys/mount.h>
44 #include <sys/sysctl.h>
46 #include <sys/utsname.h>
47 #include <sys/ktrace.h>
65 #define PATH_RTLD "/libexec/ld-elf.so.1"
67 #define PATH_RTLD "/libexec/ld-elf32.so.1"
71 typedef void (*func_ptr_type)();
72 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
75 * Function declarations.
77 static const char *basename(const char *);
78 static void die(void) __dead2;
79 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
81 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *);
82 static void digest_dynamic(Obj_Entry *, int);
83 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
84 static Obj_Entry *dlcheck(void *);
85 static Obj_Entry *dlopen_object(const char *name, Obj_Entry *refobj,
86 int lo_flags, int mode);
87 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
88 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
89 static bool donelist_check(DoneList *, const Obj_Entry *);
90 static void errmsg_restore(char *);
91 static char *errmsg_save(void);
92 static void *fill_search_info(const char *, size_t, void *);
93 static char *find_library(const char *, const Obj_Entry *);
94 static const char *gethints(void);
95 static void init_dag(Obj_Entry *);
96 static void init_rtld(caddr_t, Elf_Auxinfo **);
97 static void initlist_add_neededs(Needed_Entry *, Objlist *);
98 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
99 static void linkmap_add(Obj_Entry *);
100 static void linkmap_delete(Obj_Entry *);
101 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
102 static void unload_filtees(Obj_Entry *);
103 static int load_needed_objects(Obj_Entry *, int);
104 static int load_preload_objects(void);
105 static Obj_Entry *load_object(const char *, const Obj_Entry *, int);
106 static void map_stacks_exec(RtldLockState *);
107 static Obj_Entry *obj_from_addr(const void *);
108 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
109 static void objlist_call_init(Objlist *, RtldLockState *);
110 static void objlist_clear(Objlist *);
111 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
112 static void objlist_init(Objlist *);
113 static void objlist_push_head(Objlist *, Obj_Entry *);
114 static void objlist_push_tail(Objlist *, Obj_Entry *);
115 static void objlist_remove(Objlist *, Obj_Entry *);
116 static void *path_enumerate(const char *, path_enum_proc, void *);
117 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, RtldLockState *);
118 static int rtld_dirname(const char *, char *);
119 static int rtld_dirname_abs(const char *, char *);
120 static void rtld_exit(void);
121 static char *search_library_path(const char *, const char *);
122 static const void **get_program_var_addr(const char *, RtldLockState *);
123 static void set_program_var(const char *, const void *);
124 static int symlook_default(SymLook *, const Obj_Entry *refobj);
125 static int symlook_global(SymLook *, DoneList *);
126 static void symlook_init_from_req(SymLook *, const SymLook *);
127 static int symlook_list(SymLook *, const Objlist *, DoneList *);
128 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
129 static int symlook_obj1(SymLook *, const Obj_Entry *);
130 static void trace_loaded_objects(Obj_Entry *);
131 static void unlink_object(Obj_Entry *);
132 static void unload_object(Obj_Entry *);
133 static void unref_dag(Obj_Entry *);
134 static void ref_dag(Obj_Entry *);
135 static int origin_subst_one(char **, const char *, const char *,
136 const char *, char *);
137 static char *origin_subst(const char *, const char *);
138 static int rtld_verify_versions(const Objlist *);
139 static int rtld_verify_object_versions(Obj_Entry *);
140 static void object_add_name(Obj_Entry *, const char *);
141 static int object_match_name(const Obj_Entry *, const char *);
142 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
143 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
144 struct dl_phdr_info *phdr_info);
146 void r_debug_state(struct r_debug *, struct link_map *);
151 static char *error_message; /* Message for dlerror(), or NULL */
152 struct r_debug r_debug; /* for GDB; */
153 static bool libmap_disable; /* Disable libmap */
154 static bool ld_loadfltr; /* Immediate filters processing */
155 static char *libmap_override; /* Maps to use in addition to libmap.conf */
156 static bool trust; /* False for setuid and setgid programs */
157 static bool dangerous_ld_env; /* True if environment variables have been
158 used to affect the libraries loaded */
159 static char *ld_bind_now; /* Environment variable for immediate binding */
160 static char *ld_debug; /* Environment variable for debugging */
161 static char *ld_library_path; /* Environment variable for search path */
162 static char *ld_preload; /* Environment variable for libraries to
164 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
165 static char *ld_tracing; /* Called from ldd to print libs */
166 static char *ld_utrace; /* Use utrace() to log events. */
167 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
168 static Obj_Entry **obj_tail; /* Link field of last object in list */
169 static Obj_Entry *obj_main; /* The main program shared object */
170 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
171 static unsigned int obj_count; /* Number of objects in obj_list */
172 static unsigned int obj_loads; /* Number of objects in obj_list */
174 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
175 STAILQ_HEAD_INITIALIZER(list_global);
176 static Objlist list_main = /* Objects loaded at program startup */
177 STAILQ_HEAD_INITIALIZER(list_main);
178 static Objlist list_fini = /* Objects needing fini() calls */
179 STAILQ_HEAD_INITIALIZER(list_fini);
181 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
183 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
185 extern Elf_Dyn _DYNAMIC;
186 #pragma weak _DYNAMIC
187 #ifndef RTLD_IS_DYNAMIC
188 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
191 int osreldate, pagesize;
193 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
194 static int max_stack_flags;
197 * Global declarations normally provided by crt1. The dynamic linker is
198 * not built with crt1, so we have to provide them ourselves.
204 * Globals to control TLS allocation.
206 size_t tls_last_offset; /* Static TLS offset of last module */
207 size_t tls_last_size; /* Static TLS size of last module */
208 size_t tls_static_space; /* Static TLS space allocated */
209 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
210 int tls_max_index = 1; /* Largest module index allocated */
213 * Fill in a DoneList with an allocation large enough to hold all of
214 * the currently-loaded objects. Keep this as a macro since it calls
215 * alloca and we want that to occur within the scope of the caller.
217 #define donelist_init(dlp) \
218 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
219 assert((dlp)->objs != NULL), \
220 (dlp)->num_alloc = obj_count, \
223 #define UTRACE_DLOPEN_START 1
224 #define UTRACE_DLOPEN_STOP 2
225 #define UTRACE_DLCLOSE_START 3
226 #define UTRACE_DLCLOSE_STOP 4
227 #define UTRACE_LOAD_OBJECT 5
228 #define UTRACE_UNLOAD_OBJECT 6
229 #define UTRACE_ADD_RUNDEP 7
230 #define UTRACE_PRELOAD_FINISHED 8
231 #define UTRACE_INIT_CALL 9
232 #define UTRACE_FINI_CALL 10
235 char sig[4]; /* 'RTLD' */
238 void *mapbase; /* Used for 'parent' and 'init/fini' */
240 int refcnt; /* Used for 'mode' */
241 char name[MAXPATHLEN];
244 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
245 if (ld_utrace != NULL) \
246 ld_utrace_log(e, h, mb, ms, r, n); \
250 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
251 int refcnt, const char *name)
253 struct utrace_rtld ut;
261 ut.mapbase = mapbase;
262 ut.mapsize = mapsize;
264 bzero(ut.name, sizeof(ut.name));
266 strlcpy(ut.name, name, sizeof(ut.name));
267 utrace(&ut, sizeof(ut));
271 * Main entry point for dynamic linking. The first argument is the
272 * stack pointer. The stack is expected to be laid out as described
273 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
274 * Specifically, the stack pointer points to a word containing
275 * ARGC. Following that in the stack is a null-terminated sequence
276 * of pointers to argument strings. Then comes a null-terminated
277 * sequence of pointers to environment strings. Finally, there is a
278 * sequence of "auxiliary vector" entries.
280 * The second argument points to a place to store the dynamic linker's
281 * exit procedure pointer and the third to a place to store the main
284 * The return value is the main program's entry point.
287 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
289 Elf_Auxinfo *aux_info[AT_COUNT];
297 Objlist_Entry *entry;
299 Obj_Entry **preload_tail;
301 RtldLockState lockstate;
304 * On entry, the dynamic linker itself has not been relocated yet.
305 * Be very careful not to reference any global data until after
306 * init_rtld has returned. It is OK to reference file-scope statics
307 * and string constants, and to call static and global functions.
310 /* Find the auxiliary vector on the stack. */
313 sp += argc + 1; /* Skip over arguments and NULL terminator */
315 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
317 aux = (Elf_Auxinfo *) sp;
319 /* Digest the auxiliary vector. */
320 for (i = 0; i < AT_COUNT; i++)
322 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
323 if (auxp->a_type < AT_COUNT)
324 aux_info[auxp->a_type] = auxp;
327 /* Initialize and relocate ourselves. */
328 assert(aux_info[AT_BASE] != NULL);
329 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
331 __progname = obj_rtld.path;
332 argv0 = argv[0] != NULL ? argv[0] : "(null)";
335 trust = !issetugid();
337 ld_bind_now = getenv(LD_ "BIND_NOW");
339 * If the process is tainted, then we un-set the dangerous environment
340 * variables. The process will be marked as tainted until setuid(2)
341 * is called. If any child process calls setuid(2) we do not want any
342 * future processes to honor the potentially un-safe variables.
345 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
346 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") ||
347 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
348 unsetenv(LD_ "LOADFLTR")) {
349 _rtld_error("environment corrupt; aborting");
353 ld_debug = getenv(LD_ "DEBUG");
354 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
355 libmap_override = getenv(LD_ "LIBMAP");
356 ld_library_path = getenv(LD_ "LIBRARY_PATH");
357 ld_preload = getenv(LD_ "PRELOAD");
358 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
359 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
360 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
361 (ld_library_path != NULL) || (ld_preload != NULL) ||
362 (ld_elf_hints_path != NULL) || ld_loadfltr;
363 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
364 ld_utrace = getenv(LD_ "UTRACE");
366 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
367 ld_elf_hints_path = _PATH_ELF_HINTS;
369 if (ld_debug != NULL && *ld_debug != '\0')
371 dbg("%s is initialized, base address = %p", __progname,
372 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
373 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
374 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
376 dbg("initializing thread locks");
380 * Load the main program, or process its program header if it is
383 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
384 int fd = aux_info[AT_EXECFD]->a_un.a_val;
385 dbg("loading main program");
386 obj_main = map_object(fd, argv0, NULL);
388 if (obj_main == NULL)
390 max_stack_flags = obj->stack_flags;
391 } else { /* Main program already loaded. */
392 const Elf_Phdr *phdr;
396 dbg("processing main program's program header");
397 assert(aux_info[AT_PHDR] != NULL);
398 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
399 assert(aux_info[AT_PHNUM] != NULL);
400 phnum = aux_info[AT_PHNUM]->a_un.a_val;
401 assert(aux_info[AT_PHENT] != NULL);
402 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
403 assert(aux_info[AT_ENTRY] != NULL);
404 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
405 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
409 if (aux_info[AT_EXECPATH] != 0) {
411 char buf[MAXPATHLEN];
413 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
414 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
415 if (kexecpath[0] == '/')
416 obj_main->path = kexecpath;
417 else if (getcwd(buf, sizeof(buf)) == NULL ||
418 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
419 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
420 obj_main->path = xstrdup(argv0);
422 obj_main->path = xstrdup(buf);
424 dbg("No AT_EXECPATH");
425 obj_main->path = xstrdup(argv0);
427 dbg("obj_main path %s", obj_main->path);
428 obj_main->mainprog = true;
430 if (aux_info[AT_STACKPROT] != NULL &&
431 aux_info[AT_STACKPROT]->a_un.a_val != 0)
432 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
435 * Get the actual dynamic linker pathname from the executable if
436 * possible. (It should always be possible.) That ensures that
437 * gdb will find the right dynamic linker even if a non-standard
440 if (obj_main->interp != NULL &&
441 strcmp(obj_main->interp, obj_rtld.path) != 0) {
443 obj_rtld.path = xstrdup(obj_main->interp);
444 __progname = obj_rtld.path;
447 digest_dynamic(obj_main, 0);
449 linkmap_add(obj_main);
450 linkmap_add(&obj_rtld);
452 /* Link the main program into the list of objects. */
453 *obj_tail = obj_main;
454 obj_tail = &obj_main->next;
457 /* Make sure we don't call the main program's init and fini functions. */
458 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
460 /* Initialize a fake symbol for resolving undefined weak references. */
461 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
462 sym_zero.st_shndx = SHN_UNDEF;
463 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
466 libmap_disable = (bool)lm_init(libmap_override);
468 dbg("loading LD_PRELOAD libraries");
469 if (load_preload_objects() == -1)
471 preload_tail = obj_tail;
473 dbg("loading needed objects");
474 if (load_needed_objects(obj_main, 0) == -1)
477 /* Make a list of all objects loaded at startup. */
478 for (obj = obj_list; obj != NULL; obj = obj->next) {
479 objlist_push_tail(&list_main, obj);
483 dbg("checking for required versions");
484 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
487 if (ld_tracing) { /* We're done */
488 trace_loaded_objects(obj_main);
492 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
493 dump_relocations(obj_main);
497 /* setup TLS for main thread */
498 dbg("initializing initial thread local storage");
499 STAILQ_FOREACH(entry, &list_main, link) {
501 * Allocate all the initial objects out of the static TLS
502 * block even if they didn't ask for it.
504 allocate_tls_offset(entry->obj);
506 allocate_initial_tls(obj_list);
508 if (relocate_objects(obj_main,
509 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld, NULL) == -1)
512 dbg("doing copy relocations");
513 if (do_copy_relocations(obj_main) == -1)
516 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
517 dump_relocations(obj_main);
521 dbg("initializing key program variables");
522 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
523 set_program_var("environ", env);
524 set_program_var("__elf_aux_vector", aux);
526 /* Make a list of init functions to call. */
527 objlist_init(&initlist);
528 initlist_add_objects(obj_list, preload_tail, &initlist);
530 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
532 map_stacks_exec(NULL);
534 wlock_acquire(rtld_bind_lock, &lockstate);
535 objlist_call_init(&initlist, &lockstate);
536 objlist_clear(&initlist);
537 dbg("loading filtees");
538 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
539 if (ld_loadfltr || obj->z_loadfltr)
540 load_filtees(obj, 0, &lockstate);
542 lock_release(rtld_bind_lock, &lockstate);
544 dbg("transferring control to program entry point = %p", obj_main->entry);
546 /* Return the exit procedure and the program entry point. */
547 *exit_proc = rtld_exit;
549 return (func_ptr_type) obj_main->entry;
553 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
557 const Obj_Entry *defobj;
560 RtldLockState lockstate;
562 rlock_acquire(rtld_bind_lock, &lockstate);
563 if (sigsetjmp(lockstate.env, 0) != 0)
564 lock_upgrade(rtld_bind_lock, &lockstate);
566 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
568 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
570 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
571 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
576 target = (Elf_Addr)(defobj->relocbase + def->st_value);
578 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
579 defobj->strtab + def->st_name, basename(obj->path),
580 (void *)target, basename(defobj->path));
583 * Write the new contents for the jmpslot. Note that depending on
584 * architecture, the value which we need to return back to the
585 * lazy binding trampoline may or may not be the target
586 * address. The value returned from reloc_jmpslot() is the value
587 * that the trampoline needs.
589 target = reloc_jmpslot(where, target, defobj, obj, rel);
590 lock_release(rtld_bind_lock, &lockstate);
595 * Error reporting function. Use it like printf. If formats the message
596 * into a buffer, and sets things up so that the next call to dlerror()
597 * will return the message.
600 _rtld_error(const char *fmt, ...)
602 static char buf[512];
606 vsnprintf(buf, sizeof buf, fmt, ap);
612 * Return a dynamically-allocated copy of the current error message, if any.
617 return error_message == NULL ? NULL : xstrdup(error_message);
621 * Restore the current error message from a copy which was previously saved
622 * by errmsg_save(). The copy is freed.
625 errmsg_restore(char *saved_msg)
627 if (saved_msg == NULL)
628 error_message = NULL;
630 _rtld_error("%s", saved_msg);
636 basename(const char *name)
638 const char *p = strrchr(name, '/');
639 return p != NULL ? p + 1 : name;
642 static struct utsname uts;
645 origin_subst_one(char **res, const char *real, const char *kw, const char *subst,
655 subst_len = kw_len = 0;
659 if (subst_len == 0) {
660 subst_len = strlen(subst);
664 *res = xmalloc(PATH_MAX);
667 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) {
668 _rtld_error("Substitution of %s in %s cannot be performed",
670 if (may_free != NULL)
675 memcpy(res1, p, p1 - p);
677 memcpy(res1, subst, subst_len);
682 if (may_free != NULL)
685 *res = xstrdup(real);
689 if (may_free != NULL)
691 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) {
701 origin_subst(const char *real, const char *origin_path)
703 char *res1, *res2, *res3, *res4;
705 if (uts.sysname[0] == '\0') {
706 if (uname(&uts) != 0) {
707 _rtld_error("utsname failed: %d", errno);
711 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) ||
712 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) ||
713 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) ||
714 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3))
722 const char *msg = dlerror();
730 * Process a shared object's DYNAMIC section, and save the important
731 * information in its Obj_Entry structure.
734 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
735 const Elf_Dyn **dyn_soname)
738 Needed_Entry **needed_tail = &obj->needed;
739 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
740 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
741 int plttype = DT_REL;
746 obj->bind_now = false;
747 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
748 switch (dynp->d_tag) {
751 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
755 obj->relsize = dynp->d_un.d_val;
759 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
763 obj->pltrel = (const Elf_Rel *)
764 (obj->relocbase + dynp->d_un.d_ptr);
768 obj->pltrelsize = dynp->d_un.d_val;
772 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
776 obj->relasize = dynp->d_un.d_val;
780 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
784 plttype = dynp->d_un.d_val;
785 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
789 obj->symtab = (const Elf_Sym *)
790 (obj->relocbase + dynp->d_un.d_ptr);
794 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
798 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
802 obj->strsize = dynp->d_un.d_val;
806 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
811 obj->verneednum = dynp->d_un.d_val;
815 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
820 obj->verdefnum = dynp->d_un.d_val;
824 obj->versyms = (const Elf_Versym *)(obj->relocbase +
830 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
831 (obj->relocbase + dynp->d_un.d_ptr);
832 obj->nbuckets = hashtab[0];
833 obj->nchains = hashtab[1];
834 obj->buckets = hashtab + 2;
835 obj->chains = obj->buckets + obj->nbuckets;
841 Needed_Entry *nep = NEW(Needed_Entry);
842 nep->name = dynp->d_un.d_val;
847 needed_tail = &nep->next;
853 Needed_Entry *nep = NEW(Needed_Entry);
854 nep->name = dynp->d_un.d_val;
858 *needed_filtees_tail = nep;
859 needed_filtees_tail = &nep->next;
865 Needed_Entry *nep = NEW(Needed_Entry);
866 nep->name = dynp->d_un.d_val;
870 *needed_aux_filtees_tail = nep;
871 needed_aux_filtees_tail = &nep->next;
876 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
884 obj->symbolic = true;
888 case DT_RUNPATH: /* XXX: process separately */
890 * We have to wait until later to process this, because we
891 * might not have gotten the address of the string table yet.
901 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
905 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
909 * Don't process DT_DEBUG on MIPS as the dynamic section
910 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
915 /* XXX - not implemented yet */
917 dbg("Filling in DT_DEBUG entry");
918 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
923 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
924 obj->z_origin = true;
925 if (dynp->d_un.d_val & DF_SYMBOLIC)
926 obj->symbolic = true;
927 if (dynp->d_un.d_val & DF_TEXTREL)
929 if (dynp->d_un.d_val & DF_BIND_NOW)
930 obj->bind_now = true;
931 if (dynp->d_un.d_val & DF_STATIC_TLS)
935 case DT_MIPS_LOCAL_GOTNO:
936 obj->local_gotno = dynp->d_un.d_val;
939 case DT_MIPS_SYMTABNO:
940 obj->symtabno = dynp->d_un.d_val;
944 obj->gotsym = dynp->d_un.d_val;
947 case DT_MIPS_RLD_MAP:
950 dbg("Filling in DT_DEBUG entry");
951 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
957 if (dynp->d_un.d_val & DF_1_NOOPEN)
958 obj->z_noopen = true;
959 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
960 obj->z_origin = true;
961 if (dynp->d_un.d_val & DF_1_GLOBAL)
963 if (dynp->d_un.d_val & DF_1_BIND_NOW)
964 obj->bind_now = true;
965 if (dynp->d_un.d_val & DF_1_NODELETE)
966 obj->z_nodelete = true;
967 if (dynp->d_un.d_val & DF_1_LOADFLTR)
968 obj->z_loadfltr = true;
973 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
982 if (plttype == DT_RELA) {
983 obj->pltrela = (const Elf_Rela *) obj->pltrel;
985 obj->pltrelasize = obj->pltrelsize;
991 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
992 const Elf_Dyn *dyn_soname)
995 if (obj->z_origin && obj->origin_path == NULL) {
996 obj->origin_path = xmalloc(PATH_MAX);
997 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1001 if (dyn_rpath != NULL) {
1002 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1004 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1007 if (dyn_soname != NULL)
1008 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1012 digest_dynamic(Obj_Entry *obj, int early)
1014 const Elf_Dyn *dyn_rpath;
1015 const Elf_Dyn *dyn_soname;
1017 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname);
1018 digest_dynamic2(obj, dyn_rpath, dyn_soname);
1022 * Process a shared object's program header. This is used only for the
1023 * main program, when the kernel has already loaded the main program
1024 * into memory before calling the dynamic linker. It creates and
1025 * returns an Obj_Entry structure.
1028 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1031 const Elf_Phdr *phlimit = phdr + phnum;
1036 for (ph = phdr; ph < phlimit; ph++) {
1037 if (ph->p_type != PT_PHDR)
1041 obj->phsize = ph->p_memsz;
1042 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1046 obj->stack_flags = PF_X | PF_R | PF_W;
1048 for (ph = phdr; ph < phlimit; ph++) {
1049 switch (ph->p_type) {
1052 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1056 if (nsegs == 0) { /* First load segment */
1057 obj->vaddrbase = trunc_page(ph->p_vaddr);
1058 obj->mapbase = obj->vaddrbase + obj->relocbase;
1059 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1061 } else { /* Last load segment */
1062 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1069 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1074 obj->tlssize = ph->p_memsz;
1075 obj->tlsalign = ph->p_align;
1076 obj->tlsinitsize = ph->p_filesz;
1077 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1081 obj->stack_flags = ph->p_flags;
1086 _rtld_error("%s: too few PT_LOAD segments", path);
1095 dlcheck(void *handle)
1099 for (obj = obj_list; obj != NULL; obj = obj->next)
1100 if (obj == (Obj_Entry *) handle)
1103 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1104 _rtld_error("Invalid shared object handle %p", handle);
1111 * If the given object is already in the donelist, return true. Otherwise
1112 * add the object to the list and return false.
1115 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1119 for (i = 0; i < dlp->num_used; i++)
1120 if (dlp->objs[i] == obj)
1123 * Our donelist allocation should always be sufficient. But if
1124 * our threads locking isn't working properly, more shared objects
1125 * could have been loaded since we allocated the list. That should
1126 * never happen, but we'll handle it properly just in case it does.
1128 if (dlp->num_used < dlp->num_alloc)
1129 dlp->objs[dlp->num_used++] = obj;
1134 * Hash function for symbol table lookup. Don't even think about changing
1135 * this. It is specified by the System V ABI.
1138 elf_hash(const char *name)
1140 const unsigned char *p = (const unsigned char *) name;
1141 unsigned long h = 0;
1144 while (*p != '\0') {
1145 h = (h << 4) + *p++;
1146 if ((g = h & 0xf0000000) != 0)
1154 * Find the library with the given name, and return its full pathname.
1155 * The returned string is dynamically allocated. Generates an error
1156 * message and returns NULL if the library cannot be found.
1158 * If the second argument is non-NULL, then it refers to an already-
1159 * loaded shared object, whose library search path will be searched.
1161 * The search order is:
1163 * rpath in the referencing file
1168 find_library(const char *xname, const Obj_Entry *refobj)
1173 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1174 if (xname[0] != '/' && !trust) {
1175 _rtld_error("Absolute pathname required for shared object \"%s\"",
1179 if (refobj != NULL && refobj->z_origin)
1180 return origin_subst(xname, refobj->origin_path);
1182 return xstrdup(xname);
1185 if (libmap_disable || (refobj == NULL) ||
1186 (name = lm_find(refobj->path, xname)) == NULL)
1187 name = (char *)xname;
1189 dbg(" Searching for \"%s\"", name);
1191 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1193 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1194 (pathname = search_library_path(name, gethints())) != NULL ||
1195 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1198 if(refobj != NULL && refobj->path != NULL) {
1199 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1200 name, basename(refobj->path));
1202 _rtld_error("Shared object \"%s\" not found", name);
1208 * Given a symbol number in a referencing object, find the corresponding
1209 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1210 * no definition was found. Returns a pointer to the Obj_Entry of the
1211 * defining object via the reference parameter DEFOBJ_OUT.
1214 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1215 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1216 RtldLockState *lockstate)
1220 const Obj_Entry *defobj;
1226 * If we have already found this symbol, get the information from
1229 if (symnum >= refobj->nchains)
1230 return NULL; /* Bad object */
1231 if (cache != NULL && cache[symnum].sym != NULL) {
1232 *defobj_out = cache[symnum].obj;
1233 return cache[symnum].sym;
1236 ref = refobj->symtab + symnum;
1237 name = refobj->strtab + ref->st_name;
1242 * We don't have to do a full scale lookup if the symbol is local.
1243 * We know it will bind to the instance in this load module; to
1244 * which we already have a pointer (ie ref). By not doing a lookup,
1245 * we not only improve performance, but it also avoids unresolvable
1246 * symbols when local symbols are not in the hash table. This has
1247 * been seen with the ia64 toolchain.
1249 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1250 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1251 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1254 symlook_init(&req, name);
1256 req.ventry = fetch_ventry(refobj, symnum);
1257 req.lockstate = lockstate;
1258 res = symlook_default(&req, refobj);
1261 defobj = req.defobj_out;
1269 * If we found no definition and the reference is weak, treat the
1270 * symbol as having the value zero.
1272 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1278 *defobj_out = defobj;
1279 /* Record the information in the cache to avoid subsequent lookups. */
1280 if (cache != NULL) {
1281 cache[symnum].sym = def;
1282 cache[symnum].obj = defobj;
1285 if (refobj != &obj_rtld)
1286 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1292 * Return the search path from the ldconfig hints file, reading it if
1293 * necessary. Returns NULL if there are problems with the hints file,
1294 * or if the search path there is empty.
1301 if (hints == NULL) {
1303 struct elfhints_hdr hdr;
1306 /* Keep from trying again in case the hints file is bad. */
1309 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1)
1311 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1312 hdr.magic != ELFHINTS_MAGIC ||
1317 p = xmalloc(hdr.dirlistlen + 1);
1318 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1319 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) {
1327 return hints[0] != '\0' ? hints : NULL;
1331 init_dag(Obj_Entry *root)
1333 const Needed_Entry *needed;
1334 const Objlist_Entry *elm;
1337 if (root->dag_inited)
1339 donelist_init(&donelist);
1341 /* Root object belongs to own DAG. */
1342 objlist_push_tail(&root->dldags, root);
1343 objlist_push_tail(&root->dagmembers, root);
1344 donelist_check(&donelist, root);
1347 * Add dependencies of root object to DAG in breadth order
1348 * by exploiting the fact that each new object get added
1349 * to the tail of the dagmembers list.
1351 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1352 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1353 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1355 objlist_push_tail(&needed->obj->dldags, root);
1356 objlist_push_tail(&root->dagmembers, needed->obj);
1359 root->dag_inited = true;
1363 * Initialize the dynamic linker. The argument is the address at which
1364 * the dynamic linker has been mapped into memory. The primary task of
1365 * this function is to relocate the dynamic linker.
1368 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1370 Obj_Entry objtmp; /* Temporary rtld object */
1371 const Elf_Dyn *dyn_rpath;
1372 const Elf_Dyn *dyn_soname;
1375 * Conjure up an Obj_Entry structure for the dynamic linker.
1377 * The "path" member can't be initialized yet because string constants
1378 * cannot yet be accessed. Below we will set it correctly.
1380 memset(&objtmp, 0, sizeof(objtmp));
1383 objtmp.mapbase = mapbase;
1385 objtmp.relocbase = mapbase;
1387 if (RTLD_IS_DYNAMIC()) {
1388 objtmp.dynamic = rtld_dynamic(&objtmp);
1389 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname);
1390 assert(objtmp.needed == NULL);
1391 #if !defined(__mips__)
1392 /* MIPS has a bogus DT_TEXTREL. */
1393 assert(!objtmp.textrel);
1397 * Temporarily put the dynamic linker entry into the object list, so
1398 * that symbols can be found.
1401 relocate_objects(&objtmp, true, &objtmp, NULL);
1404 /* Initialize the object list. */
1405 obj_tail = &obj_list;
1407 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1408 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1410 if (aux_info[AT_PAGESZ] != NULL)
1411 pagesize = aux_info[AT_PAGESZ]->a_un.a_val;
1412 if (aux_info[AT_OSRELDATE] != NULL)
1413 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1415 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname);
1417 /* Replace the path with a dynamically allocated copy. */
1418 obj_rtld.path = xstrdup(PATH_RTLD);
1420 r_debug.r_brk = r_debug_state;
1421 r_debug.r_state = RT_CONSISTENT;
1425 * Add the init functions from a needed object list (and its recursive
1426 * needed objects) to "list". This is not used directly; it is a helper
1427 * function for initlist_add_objects(). The write lock must be held
1428 * when this function is called.
1431 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1433 /* Recursively process the successor needed objects. */
1434 if (needed->next != NULL)
1435 initlist_add_neededs(needed->next, list);
1437 /* Process the current needed object. */
1438 if (needed->obj != NULL)
1439 initlist_add_objects(needed->obj, &needed->obj->next, list);
1443 * Scan all of the DAGs rooted in the range of objects from "obj" to
1444 * "tail" and add their init functions to "list". This recurses over
1445 * the DAGs and ensure the proper init ordering such that each object's
1446 * needed libraries are initialized before the object itself. At the
1447 * same time, this function adds the objects to the global finalization
1448 * list "list_fini" in the opposite order. The write lock must be
1449 * held when this function is called.
1452 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1454 if (obj->init_scanned || obj->init_done)
1456 obj->init_scanned = true;
1458 /* Recursively process the successor objects. */
1459 if (&obj->next != tail)
1460 initlist_add_objects(obj->next, tail, list);
1462 /* Recursively process the needed objects. */
1463 if (obj->needed != NULL)
1464 initlist_add_neededs(obj->needed, list);
1466 /* Add the object to the init list. */
1467 if (obj->init != (Elf_Addr)NULL)
1468 objlist_push_tail(list, obj);
1470 /* Add the object to the global fini list in the reverse order. */
1471 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) {
1472 objlist_push_head(&list_fini, obj);
1473 obj->on_fini_list = true;
1478 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1482 free_needed_filtees(Needed_Entry *n)
1484 Needed_Entry *needed, *needed1;
1486 for (needed = n; needed != NULL; needed = needed->next) {
1487 if (needed->obj != NULL) {
1488 dlclose(needed->obj);
1492 for (needed = n; needed != NULL; needed = needed1) {
1493 needed1 = needed->next;
1499 unload_filtees(Obj_Entry *obj)
1502 free_needed_filtees(obj->needed_filtees);
1503 obj->needed_filtees = NULL;
1504 free_needed_filtees(obj->needed_aux_filtees);
1505 obj->needed_aux_filtees = NULL;
1506 obj->filtees_loaded = false;
1510 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags)
1513 for (; needed != NULL; needed = needed->next) {
1514 needed->obj = dlopen_object(obj->strtab + needed->name, obj,
1515 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
1521 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
1524 lock_restart_for_upgrade(lockstate);
1525 if (!obj->filtees_loaded) {
1526 load_filtee1(obj, obj->needed_filtees, flags);
1527 load_filtee1(obj, obj->needed_aux_filtees, flags);
1528 obj->filtees_loaded = true;
1533 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
1537 for (; needed != NULL; needed = needed->next) {
1538 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj,
1539 flags & ~RTLD_LO_NOLOAD);
1540 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
1542 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) {
1543 dbg("obj %s nodelete", obj1->path);
1546 obj1->ref_nodel = true;
1553 * Given a shared object, traverse its list of needed objects, and load
1554 * each of them. Returns 0 on success. Generates an error message and
1555 * returns -1 on failure.
1558 load_needed_objects(Obj_Entry *first, int flags)
1562 for (obj = first; obj != NULL; obj = obj->next) {
1563 if (process_needed(obj, obj->needed, flags) == -1)
1570 load_preload_objects(void)
1572 char *p = ld_preload;
1573 static const char delim[] = " \t:;";
1578 p += strspn(p, delim);
1579 while (*p != '\0') {
1580 size_t len = strcspn(p, delim);
1585 if (load_object(p, NULL, 0) == NULL)
1586 return -1; /* XXX - cleanup */
1589 p += strspn(p, delim);
1591 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
1596 * Load a shared object into memory, if it is not already loaded.
1598 * Returns a pointer to the Obj_Entry for the object. Returns NULL
1602 load_object(const char *name, const Obj_Entry *refobj, int flags)
1609 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1610 if (object_match_name(obj, name))
1613 path = find_library(name, refobj);
1618 * If we didn't find a match by pathname, open the file and check
1619 * again by device and inode. This avoids false mismatches caused
1620 * by multiple links or ".." in pathnames.
1622 * To avoid a race, we open the file and use fstat() rather than
1625 if ((fd = open(path, O_RDONLY)) == -1) {
1626 _rtld_error("Cannot open \"%s\"", path);
1630 if (fstat(fd, &sb) == -1) {
1631 _rtld_error("Cannot fstat \"%s\"", path);
1636 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1637 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
1640 object_add_name(obj, name);
1645 if (flags & RTLD_LO_NOLOAD) {
1650 /* First use of this object, so we must map it in */
1651 obj = do_load_object(fd, name, path, &sb, flags);
1660 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
1667 * but first, make sure that environment variables haven't been
1668 * used to circumvent the noexec flag on a filesystem.
1670 if (dangerous_ld_env) {
1671 if (fstatfs(fd, &fs) != 0) {
1672 _rtld_error("Cannot fstatfs \"%s\"", path);
1675 if (fs.f_flags & MNT_NOEXEC) {
1676 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
1680 dbg("loading \"%s\"", path);
1681 obj = map_object(fd, path, sbp);
1685 object_add_name(obj, name);
1687 digest_dynamic(obj, 0);
1688 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
1690 dbg("refusing to load non-loadable \"%s\"", obj->path);
1691 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
1692 munmap(obj->mapbase, obj->mapsize);
1698 obj_tail = &obj->next;
1701 linkmap_add(obj); /* for GDB & dlinfo() */
1702 max_stack_flags |= obj->stack_flags;
1704 dbg(" %p .. %p: %s", obj->mapbase,
1705 obj->mapbase + obj->mapsize - 1, obj->path);
1707 dbg(" WARNING: %s has impure text", obj->path);
1708 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
1715 obj_from_addr(const void *addr)
1719 for (obj = obj_list; obj != NULL; obj = obj->next) {
1720 if (addr < (void *) obj->mapbase)
1722 if (addr < (void *) (obj->mapbase + obj->mapsize))
1729 * Call the finalization functions for each of the objects in "list"
1730 * belonging to the DAG of "root" and referenced once. If NULL "root"
1731 * is specified, every finalization function will be called regardless
1732 * of the reference count and the list elements won't be freed. All of
1733 * the objects are expected to have non-NULL fini functions.
1736 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
1741 assert(root == NULL || root->refcount == 1);
1744 * Preserve the current error message since a fini function might
1745 * call into the dynamic linker and overwrite it.
1747 saved_msg = errmsg_save();
1749 STAILQ_FOREACH(elm, list, link) {
1750 if (root != NULL && (elm->obj->refcount != 1 ||
1751 objlist_find(&root->dagmembers, elm->obj) == NULL))
1753 dbg("calling fini function for %s at %p", elm->obj->path,
1754 (void *)elm->obj->fini);
1755 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0,
1757 /* Remove object from fini list to prevent recursive invocation. */
1758 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
1760 * XXX: If a dlopen() call references an object while the
1761 * fini function is in progress, we might end up trying to
1762 * unload the referenced object in dlclose() or the object
1763 * won't be unloaded although its fini function has been
1766 lock_release(rtld_bind_lock, lockstate);
1767 call_initfini_pointer(elm->obj, elm->obj->fini);
1768 wlock_acquire(rtld_bind_lock, lockstate);
1769 /* No need to free anything if process is going down. */
1773 * We must restart the list traversal after every fini call
1774 * because a dlclose() call from the fini function or from
1775 * another thread might have modified the reference counts.
1779 } while (elm != NULL);
1780 errmsg_restore(saved_msg);
1784 * Call the initialization functions for each of the objects in
1785 * "list". All of the objects are expected to have non-NULL init
1789 objlist_call_init(Objlist *list, RtldLockState *lockstate)
1796 * Clean init_scanned flag so that objects can be rechecked and
1797 * possibly initialized earlier if any of vectors called below
1798 * cause the change by using dlopen.
1800 for (obj = obj_list; obj != NULL; obj = obj->next)
1801 obj->init_scanned = false;
1804 * Preserve the current error message since an init function might
1805 * call into the dynamic linker and overwrite it.
1807 saved_msg = errmsg_save();
1808 STAILQ_FOREACH(elm, list, link) {
1809 if (elm->obj->init_done) /* Initialized early. */
1811 dbg("calling init function for %s at %p", elm->obj->path,
1812 (void *)elm->obj->init);
1813 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0,
1816 * Race: other thread might try to use this object before current
1817 * one completes the initilization. Not much can be done here
1818 * without better locking.
1820 elm->obj->init_done = true;
1821 lock_release(rtld_bind_lock, lockstate);
1822 call_initfini_pointer(elm->obj, elm->obj->init);
1823 wlock_acquire(rtld_bind_lock, lockstate);
1825 errmsg_restore(saved_msg);
1829 objlist_clear(Objlist *list)
1833 while (!STAILQ_EMPTY(list)) {
1834 elm = STAILQ_FIRST(list);
1835 STAILQ_REMOVE_HEAD(list, link);
1840 static Objlist_Entry *
1841 objlist_find(Objlist *list, const Obj_Entry *obj)
1845 STAILQ_FOREACH(elm, list, link)
1846 if (elm->obj == obj)
1852 objlist_init(Objlist *list)
1858 objlist_push_head(Objlist *list, Obj_Entry *obj)
1862 elm = NEW(Objlist_Entry);
1864 STAILQ_INSERT_HEAD(list, elm, link);
1868 objlist_push_tail(Objlist *list, Obj_Entry *obj)
1872 elm = NEW(Objlist_Entry);
1874 STAILQ_INSERT_TAIL(list, elm, link);
1878 objlist_remove(Objlist *list, Obj_Entry *obj)
1882 if ((elm = objlist_find(list, obj)) != NULL) {
1883 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
1889 * Relocate newly-loaded shared objects. The argument is a pointer to
1890 * the Obj_Entry for the first such object. All objects from the first
1891 * to the end of the list of objects are relocated. Returns 0 on success,
1895 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
1896 RtldLockState *lockstate)
1900 for (obj = first; obj != NULL; obj = obj->next) {
1902 dbg("relocating \"%s\"", obj->path);
1903 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL ||
1904 obj->symtab == NULL || obj->strtab == NULL) {
1905 _rtld_error("%s: Shared object has no run-time symbol table",
1911 /* There are relocations to the write-protected text segment. */
1912 if (mprotect(obj->mapbase, obj->textsize,
1913 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
1914 _rtld_error("%s: Cannot write-enable text segment: %s",
1915 obj->path, strerror(errno));
1920 /* Process the non-PLT relocations. */
1921 if (reloc_non_plt(obj, rtldobj, lockstate))
1924 if (obj->textrel) { /* Re-protected the text segment. */
1925 if (mprotect(obj->mapbase, obj->textsize,
1926 PROT_READ|PROT_EXEC) == -1) {
1927 _rtld_error("%s: Cannot write-protect text segment: %s",
1928 obj->path, strerror(errno));
1933 /* Process the PLT relocations. */
1934 if (reloc_plt(obj) == -1)
1936 /* Relocate the jump slots if we are doing immediate binding. */
1937 if (obj->bind_now || bind_now)
1938 if (reloc_jmpslots(obj, lockstate) == -1)
1943 * Set up the magic number and version in the Obj_Entry. These
1944 * were checked in the crt1.o from the original ElfKit, so we
1945 * set them for backward compatibility.
1947 obj->magic = RTLD_MAGIC;
1948 obj->version = RTLD_VERSION;
1950 /* Set the special PLT or GOT entries. */
1958 * Cleanup procedure. It will be called (by the atexit mechanism) just
1959 * before the process exits.
1964 RtldLockState lockstate;
1966 wlock_acquire(rtld_bind_lock, &lockstate);
1968 objlist_call_fini(&list_fini, NULL, &lockstate);
1969 /* No need to remove the items from the list, since we are exiting. */
1970 if (!libmap_disable)
1972 lock_release(rtld_bind_lock, &lockstate);
1976 path_enumerate(const char *path, path_enum_proc callback, void *arg)
1984 path += strspn(path, ":;");
1985 while (*path != '\0') {
1989 len = strcspn(path, ":;");
1991 trans = lm_findn(NULL, path, len);
1993 res = callback(trans, strlen(trans), arg);
1996 res = callback(path, len, arg);
2002 path += strspn(path, ":;");
2008 struct try_library_args {
2016 try_library_path(const char *dir, size_t dirlen, void *param)
2018 struct try_library_args *arg;
2021 if (*dir == '/' || trust) {
2024 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2027 pathname = arg->buffer;
2028 strncpy(pathname, dir, dirlen);
2029 pathname[dirlen] = '/';
2030 strcpy(pathname + dirlen + 1, arg->name);
2032 dbg(" Trying \"%s\"", pathname);
2033 if (access(pathname, F_OK) == 0) { /* We found it */
2034 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2035 strcpy(pathname, arg->buffer);
2043 search_library_path(const char *name, const char *path)
2046 struct try_library_args arg;
2052 arg.namelen = strlen(name);
2053 arg.buffer = xmalloc(PATH_MAX);
2054 arg.buflen = PATH_MAX;
2056 p = path_enumerate(path, try_library_path, &arg);
2064 dlclose(void *handle)
2067 RtldLockState lockstate;
2069 wlock_acquire(rtld_bind_lock, &lockstate);
2070 root = dlcheck(handle);
2072 lock_release(rtld_bind_lock, &lockstate);
2075 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2078 /* Unreference the object and its dependencies. */
2079 root->dl_refcount--;
2081 if (root->refcount == 1) {
2083 * The object will be no longer referenced, so we must unload it.
2084 * First, call the fini functions.
2086 objlist_call_fini(&list_fini, root, &lockstate);
2090 /* Finish cleaning up the newly-unreferenced objects. */
2091 GDB_STATE(RT_DELETE,&root->linkmap);
2092 unload_object(root);
2093 GDB_STATE(RT_CONSISTENT,NULL);
2097 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2098 lock_release(rtld_bind_lock, &lockstate);
2105 char *msg = error_message;
2106 error_message = NULL;
2111 * This function is deprecated and has no effect.
2114 dllockinit(void *context,
2115 void *(*lock_create)(void *context),
2116 void (*rlock_acquire)(void *lock),
2117 void (*wlock_acquire)(void *lock),
2118 void (*lock_release)(void *lock),
2119 void (*lock_destroy)(void *lock),
2120 void (*context_destroy)(void *context))
2122 static void *cur_context;
2123 static void (*cur_context_destroy)(void *);
2125 /* Just destroy the context from the previous call, if necessary. */
2126 if (cur_context_destroy != NULL)
2127 cur_context_destroy(cur_context);
2128 cur_context = context;
2129 cur_context_destroy = context_destroy;
2133 dlopen(const char *name, int mode)
2135 RtldLockState lockstate;
2138 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2139 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2140 if (ld_tracing != NULL) {
2141 rlock_acquire(rtld_bind_lock, &lockstate);
2142 if (sigsetjmp(lockstate.env, 0) != 0)
2143 lock_upgrade(rtld_bind_lock, &lockstate);
2144 environ = (char **)*get_program_var_addr("environ", &lockstate);
2145 lock_release(rtld_bind_lock, &lockstate);
2147 lo_flags = RTLD_LO_DLOPEN;
2148 if (mode & RTLD_NODELETE)
2149 lo_flags |= RTLD_LO_NODELETE;
2150 if (mode & RTLD_NOLOAD)
2151 lo_flags |= RTLD_LO_NOLOAD;
2152 if (ld_tracing != NULL)
2153 lo_flags |= RTLD_LO_TRACE;
2155 return (dlopen_object(name, obj_main, lo_flags,
2156 mode & (RTLD_MODEMASK | RTLD_GLOBAL)));
2160 dlopen_object(const char *name, Obj_Entry *refobj, int lo_flags, int mode)
2162 Obj_Entry **old_obj_tail;
2165 RtldLockState lockstate;
2168 objlist_init(&initlist);
2170 wlock_acquire(rtld_bind_lock, &lockstate);
2171 GDB_STATE(RT_ADD,NULL);
2173 old_obj_tail = obj_tail;
2179 obj = load_object(name, refobj, lo_flags);
2184 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2185 objlist_push_tail(&list_global, obj);
2186 if (*old_obj_tail != NULL) { /* We loaded something new. */
2187 assert(*old_obj_tail == obj);
2188 result = load_needed_objects(obj, lo_flags & RTLD_LO_DLOPEN);
2192 result = rtld_verify_versions(&obj->dagmembers);
2193 if (result != -1 && ld_tracing)
2195 if (result == -1 || (relocate_objects(obj, (mode & RTLD_MODEMASK)
2196 == RTLD_NOW, &obj_rtld, &lockstate)) == -1) {
2199 if (obj->refcount == 0)
2203 /* Make list of init functions to call. */
2204 initlist_add_objects(obj, &obj->next, &initlist);
2209 * Bump the reference counts for objects on this DAG. If
2210 * this is the first dlopen() call for the object that was
2211 * already loaded as a dependency, initialize the dag
2217 if ((lo_flags & RTLD_LO_TRACE) != 0)
2220 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2221 obj->z_nodelete) && !obj->ref_nodel) {
2222 dbg("obj %s nodelete", obj->path);
2224 obj->z_nodelete = obj->ref_nodel = true;
2228 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2230 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2232 map_stacks_exec(&lockstate);
2234 /* Call the init functions. */
2235 objlist_call_init(&initlist, &lockstate);
2236 objlist_clear(&initlist);
2237 lock_release(rtld_bind_lock, &lockstate);
2240 trace_loaded_objects(obj);
2241 lock_release(rtld_bind_lock, &lockstate);
2246 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
2250 const Obj_Entry *obj, *defobj;
2253 RtldLockState lockstate;
2258 symlook_init(&req, name);
2260 req.flags = flags | SYMLOOK_IN_PLT;
2261 req.lockstate = &lockstate;
2263 rlock_acquire(rtld_bind_lock, &lockstate);
2264 if (sigsetjmp(lockstate.env, 0) != 0)
2265 lock_upgrade(rtld_bind_lock, &lockstate);
2266 if (handle == NULL || handle == RTLD_NEXT ||
2267 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
2269 if ((obj = obj_from_addr(retaddr)) == NULL) {
2270 _rtld_error("Cannot determine caller's shared object");
2271 lock_release(rtld_bind_lock, &lockstate);
2274 if (handle == NULL) { /* Just the caller's shared object. */
2275 res = symlook_obj(&req, obj);
2278 defobj = req.defobj_out;
2280 } else if (handle == RTLD_NEXT || /* Objects after caller's */
2281 handle == RTLD_SELF) { /* ... caller included */
2282 if (handle == RTLD_NEXT)
2284 for (; obj != NULL; obj = obj->next) {
2285 res = symlook_obj(&req, obj);
2288 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
2290 defobj = req.defobj_out;
2291 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
2297 * Search the dynamic linker itself, and possibly resolve the
2298 * symbol from there. This is how the application links to
2299 * dynamic linker services such as dlopen.
2301 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2302 res = symlook_obj(&req, &obj_rtld);
2305 defobj = req.defobj_out;
2309 assert(handle == RTLD_DEFAULT);
2310 res = symlook_default(&req, obj);
2312 defobj = req.defobj_out;
2317 if ((obj = dlcheck(handle)) == NULL) {
2318 lock_release(rtld_bind_lock, &lockstate);
2322 donelist_init(&donelist);
2323 if (obj->mainprog) {
2324 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
2325 res = symlook_global(&req, &donelist);
2328 defobj = req.defobj_out;
2331 * Search the dynamic linker itself, and possibly resolve the
2332 * symbol from there. This is how the application links to
2333 * dynamic linker services such as dlopen.
2335 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2336 res = symlook_obj(&req, &obj_rtld);
2339 defobj = req.defobj_out;
2344 /* Search the whole DAG rooted at the given object. */
2345 res = symlook_list(&req, &obj->dagmembers, &donelist);
2348 defobj = req.defobj_out;
2354 lock_release(rtld_bind_lock, &lockstate);
2357 * The value required by the caller is derived from the value
2358 * of the symbol. For the ia64 architecture, we need to
2359 * construct a function descriptor which the caller can use to
2360 * call the function with the right 'gp' value. For other
2361 * architectures and for non-functions, the value is simply
2362 * the relocated value of the symbol.
2364 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
2365 return make_function_pointer(def, defobj);
2367 return defobj->relocbase + def->st_value;
2370 _rtld_error("Undefined symbol \"%s\"", name);
2371 lock_release(rtld_bind_lock, &lockstate);
2376 dlsym(void *handle, const char *name)
2378 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
2383 dlfunc(void *handle, const char *name)
2390 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
2396 dlvsym(void *handle, const char *name, const char *version)
2400 ventry.name = version;
2402 ventry.hash = elf_hash(version);
2404 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
2409 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
2411 const Obj_Entry *obj;
2412 RtldLockState lockstate;
2414 rlock_acquire(rtld_bind_lock, &lockstate);
2415 obj = obj_from_addr(addr);
2417 _rtld_error("No shared object contains address");
2418 lock_release(rtld_bind_lock, &lockstate);
2421 rtld_fill_dl_phdr_info(obj, phdr_info);
2422 lock_release(rtld_bind_lock, &lockstate);
2427 dladdr(const void *addr, Dl_info *info)
2429 const Obj_Entry *obj;
2432 unsigned long symoffset;
2433 RtldLockState lockstate;
2435 rlock_acquire(rtld_bind_lock, &lockstate);
2436 obj = obj_from_addr(addr);
2438 _rtld_error("No shared object contains address");
2439 lock_release(rtld_bind_lock, &lockstate);
2442 info->dli_fname = obj->path;
2443 info->dli_fbase = obj->mapbase;
2444 info->dli_saddr = (void *)0;
2445 info->dli_sname = NULL;
2448 * Walk the symbol list looking for the symbol whose address is
2449 * closest to the address sent in.
2451 for (symoffset = 0; symoffset < obj->nchains; symoffset++) {
2452 def = obj->symtab + symoffset;
2455 * For skip the symbol if st_shndx is either SHN_UNDEF or
2458 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
2462 * If the symbol is greater than the specified address, or if it
2463 * is further away from addr than the current nearest symbol,
2466 symbol_addr = obj->relocbase + def->st_value;
2467 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
2470 /* Update our idea of the nearest symbol. */
2471 info->dli_sname = obj->strtab + def->st_name;
2472 info->dli_saddr = symbol_addr;
2475 if (info->dli_saddr == addr)
2478 lock_release(rtld_bind_lock, &lockstate);
2483 dlinfo(void *handle, int request, void *p)
2485 const Obj_Entry *obj;
2486 RtldLockState lockstate;
2489 rlock_acquire(rtld_bind_lock, &lockstate);
2491 if (handle == NULL || handle == RTLD_SELF) {
2494 retaddr = __builtin_return_address(0); /* __GNUC__ only */
2495 if ((obj = obj_from_addr(retaddr)) == NULL)
2496 _rtld_error("Cannot determine caller's shared object");
2498 obj = dlcheck(handle);
2501 lock_release(rtld_bind_lock, &lockstate);
2507 case RTLD_DI_LINKMAP:
2508 *((struct link_map const **)p) = &obj->linkmap;
2510 case RTLD_DI_ORIGIN:
2511 error = rtld_dirname(obj->path, p);
2514 case RTLD_DI_SERINFOSIZE:
2515 case RTLD_DI_SERINFO:
2516 error = do_search_info(obj, request, (struct dl_serinfo *)p);
2520 _rtld_error("Invalid request %d passed to dlinfo()", request);
2524 lock_release(rtld_bind_lock, &lockstate);
2530 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
2533 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
2534 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
2535 STAILQ_FIRST(&obj->names)->name : obj->path;
2536 phdr_info->dlpi_phdr = obj->phdr;
2537 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
2538 phdr_info->dlpi_tls_modid = obj->tlsindex;
2539 phdr_info->dlpi_tls_data = obj->tlsinit;
2540 phdr_info->dlpi_adds = obj_loads;
2541 phdr_info->dlpi_subs = obj_loads - obj_count;
2545 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
2547 struct dl_phdr_info phdr_info;
2548 const Obj_Entry *obj;
2549 RtldLockState bind_lockstate, phdr_lockstate;
2552 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
2553 rlock_acquire(rtld_bind_lock, &bind_lockstate);
2557 for (obj = obj_list; obj != NULL; obj = obj->next) {
2558 rtld_fill_dl_phdr_info(obj, &phdr_info);
2559 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
2563 lock_release(rtld_bind_lock, &bind_lockstate);
2564 lock_release(rtld_phdr_lock, &phdr_lockstate);
2569 struct fill_search_info_args {
2572 Dl_serinfo *serinfo;
2573 Dl_serpath *serpath;
2578 fill_search_info(const char *dir, size_t dirlen, void *param)
2580 struct fill_search_info_args *arg;
2584 if (arg->request == RTLD_DI_SERINFOSIZE) {
2585 arg->serinfo->dls_cnt ++;
2586 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1;
2588 struct dl_serpath *s_entry;
2590 s_entry = arg->serpath;
2591 s_entry->dls_name = arg->strspace;
2592 s_entry->dls_flags = arg->flags;
2594 strncpy(arg->strspace, dir, dirlen);
2595 arg->strspace[dirlen] = '\0';
2597 arg->strspace += dirlen + 1;
2605 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
2607 struct dl_serinfo _info;
2608 struct fill_search_info_args args;
2610 args.request = RTLD_DI_SERINFOSIZE;
2611 args.serinfo = &_info;
2613 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2616 path_enumerate(ld_library_path, fill_search_info, &args);
2617 path_enumerate(obj->rpath, fill_search_info, &args);
2618 path_enumerate(gethints(), fill_search_info, &args);
2619 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
2622 if (request == RTLD_DI_SERINFOSIZE) {
2623 info->dls_size = _info.dls_size;
2624 info->dls_cnt = _info.dls_cnt;
2628 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
2629 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
2633 args.request = RTLD_DI_SERINFO;
2634 args.serinfo = info;
2635 args.serpath = &info->dls_serpath[0];
2636 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
2638 args.flags = LA_SER_LIBPATH;
2639 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
2642 args.flags = LA_SER_RUNPATH;
2643 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
2646 args.flags = LA_SER_CONFIG;
2647 if (path_enumerate(gethints(), fill_search_info, &args) != NULL)
2650 args.flags = LA_SER_DEFAULT;
2651 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
2657 rtld_dirname(const char *path, char *bname)
2661 /* Empty or NULL string gets treated as "." */
2662 if (path == NULL || *path == '\0') {
2668 /* Strip trailing slashes */
2669 endp = path + strlen(path) - 1;
2670 while (endp > path && *endp == '/')
2673 /* Find the start of the dir */
2674 while (endp > path && *endp != '/')
2677 /* Either the dir is "/" or there are no slashes */
2679 bname[0] = *endp == '/' ? '/' : '.';
2685 } while (endp > path && *endp == '/');
2688 if (endp - path + 2 > PATH_MAX)
2690 _rtld_error("Filename is too long: %s", path);
2694 strncpy(bname, path, endp - path + 1);
2695 bname[endp - path + 1] = '\0';
2700 rtld_dirname_abs(const char *path, char *base)
2702 char base_rel[PATH_MAX];
2704 if (rtld_dirname(path, base) == -1)
2708 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
2709 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
2710 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
2712 strcpy(base, base_rel);
2717 linkmap_add(Obj_Entry *obj)
2719 struct link_map *l = &obj->linkmap;
2720 struct link_map *prev;
2722 obj->linkmap.l_name = obj->path;
2723 obj->linkmap.l_addr = obj->mapbase;
2724 obj->linkmap.l_ld = obj->dynamic;
2726 /* GDB needs load offset on MIPS to use the symbols */
2727 obj->linkmap.l_offs = obj->relocbase;
2730 if (r_debug.r_map == NULL) {
2736 * Scan to the end of the list, but not past the entry for the
2737 * dynamic linker, which we want to keep at the very end.
2739 for (prev = r_debug.r_map;
2740 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
2741 prev = prev->l_next)
2744 /* Link in the new entry. */
2746 l->l_next = prev->l_next;
2747 if (l->l_next != NULL)
2748 l->l_next->l_prev = l;
2753 linkmap_delete(Obj_Entry *obj)
2755 struct link_map *l = &obj->linkmap;
2757 if (l->l_prev == NULL) {
2758 if ((r_debug.r_map = l->l_next) != NULL)
2759 l->l_next->l_prev = NULL;
2763 if ((l->l_prev->l_next = l->l_next) != NULL)
2764 l->l_next->l_prev = l->l_prev;
2768 * Function for the debugger to set a breakpoint on to gain control.
2770 * The two parameters allow the debugger to easily find and determine
2771 * what the runtime loader is doing and to whom it is doing it.
2773 * When the loadhook trap is hit (r_debug_state, set at program
2774 * initialization), the arguments can be found on the stack:
2776 * +8 struct link_map *m
2777 * +4 struct r_debug *rd
2781 r_debug_state(struct r_debug* rd, struct link_map *m)
2786 * Get address of the pointer variable in the main program.
2787 * Prefer non-weak symbol over the weak one.
2789 static const void **
2790 get_program_var_addr(const char *name, RtldLockState *lockstate)
2795 symlook_init(&req, name);
2796 req.lockstate = lockstate;
2797 donelist_init(&donelist);
2798 if (symlook_global(&req, &donelist) != 0)
2800 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
2801 return ((const void **)make_function_pointer(req.sym_out,
2804 return ((const void **)(req.defobj_out->relocbase +
2805 req.sym_out->st_value));
2809 * Set a pointer variable in the main program to the given value. This
2810 * is used to set key variables such as "environ" before any of the
2811 * init functions are called.
2814 set_program_var(const char *name, const void *value)
2818 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
2819 dbg("\"%s\": *%p <-- %p", name, addr, value);
2825 * Search the global objects, including dependencies and main object,
2826 * for the given symbol.
2829 symlook_global(SymLook *req, DoneList *donelist)
2832 const Objlist_Entry *elm;
2835 symlook_init_from_req(&req1, req);
2837 /* Search all objects loaded at program start up. */
2838 if (req->defobj_out == NULL ||
2839 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
2840 res = symlook_list(&req1, &list_main, donelist);
2841 if (res == 0 && (req->defobj_out == NULL ||
2842 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
2843 req->sym_out = req1.sym_out;
2844 req->defobj_out = req1.defobj_out;
2845 assert(req->defobj_out != NULL);
2849 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
2850 STAILQ_FOREACH(elm, &list_global, link) {
2851 if (req->defobj_out != NULL &&
2852 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
2854 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
2855 if (res == 0 && (req->defobj_out == NULL ||
2856 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
2857 req->sym_out = req1.sym_out;
2858 req->defobj_out = req1.defobj_out;
2859 assert(req->defobj_out != NULL);
2863 return (req->sym_out != NULL ? 0 : ESRCH);
2867 * Given a symbol name in a referencing object, find the corresponding
2868 * definition of the symbol. Returns a pointer to the symbol, or NULL if
2869 * no definition was found. Returns a pointer to the Obj_Entry of the
2870 * defining object via the reference parameter DEFOBJ_OUT.
2873 symlook_default(SymLook *req, const Obj_Entry *refobj)
2876 const Objlist_Entry *elm;
2880 donelist_init(&donelist);
2881 symlook_init_from_req(&req1, req);
2883 /* Look first in the referencing object if linked symbolically. */
2884 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
2885 res = symlook_obj(&req1, refobj);
2887 req->sym_out = req1.sym_out;
2888 req->defobj_out = req1.defobj_out;
2889 assert(req->defobj_out != NULL);
2893 symlook_global(req, &donelist);
2895 /* Search all dlopened DAGs containing the referencing object. */
2896 STAILQ_FOREACH(elm, &refobj->dldags, link) {
2897 if (req->sym_out != NULL &&
2898 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
2900 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
2901 if (res == 0 && (req->sym_out == NULL ||
2902 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
2903 req->sym_out = req1.sym_out;
2904 req->defobj_out = req1.defobj_out;
2905 assert(req->defobj_out != NULL);
2910 * Search the dynamic linker itself, and possibly resolve the
2911 * symbol from there. This is how the application links to
2912 * dynamic linker services such as dlopen.
2914 if (req->sym_out == NULL ||
2915 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
2916 res = symlook_obj(&req1, &obj_rtld);
2918 req->sym_out = req1.sym_out;
2919 req->defobj_out = req1.defobj_out;
2920 assert(req->defobj_out != NULL);
2924 return (req->sym_out != NULL ? 0 : ESRCH);
2928 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
2931 const Obj_Entry *defobj;
2932 const Objlist_Entry *elm;
2938 STAILQ_FOREACH(elm, objlist, link) {
2939 if (donelist_check(dlp, elm->obj))
2941 symlook_init_from_req(&req1, req);
2942 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
2943 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
2945 defobj = req1.defobj_out;
2946 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
2953 req->defobj_out = defobj;
2960 * Search the chain of DAGS cointed to by the given Needed_Entry
2961 * for a symbol of the given name. Each DAG is scanned completely
2962 * before advancing to the next one. Returns a pointer to the symbol,
2963 * or NULL if no definition was found.
2966 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
2969 const Needed_Entry *n;
2970 const Obj_Entry *defobj;
2976 symlook_init_from_req(&req1, req);
2977 for (n = needed; n != NULL; n = n->next) {
2978 if (n->obj == NULL ||
2979 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
2981 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
2983 defobj = req1.defobj_out;
2984 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
2990 req->defobj_out = defobj;
2997 * Search the symbol table of a single shared object for a symbol of
2998 * the given name and version, if requested. Returns a pointer to the
2999 * symbol, or NULL if no definition was found. If the object is
3000 * filter, return filtered symbol from filtee.
3002 * The symbol's hash value is passed in for efficiency reasons; that
3003 * eliminates many recomputations of the hash value.
3006 symlook_obj(SymLook *req, const Obj_Entry *obj)
3012 mres = symlook_obj1(req, obj);
3014 if (obj->needed_filtees != NULL) {
3015 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate);
3016 donelist_init(&donelist);
3017 symlook_init_from_req(&req1, req);
3018 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3020 req->sym_out = req1.sym_out;
3021 req->defobj_out = req1.defobj_out;
3025 if (obj->needed_aux_filtees != NULL) {
3026 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate);
3027 donelist_init(&donelist);
3028 symlook_init_from_req(&req1, req);
3029 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3031 req->sym_out = req1.sym_out;
3032 req->defobj_out = req1.defobj_out;
3041 symlook_obj1(SymLook *req, const Obj_Entry *obj)
3043 unsigned long symnum;
3044 const Elf_Sym *vsymp;
3048 if (obj->buckets == NULL)
3053 symnum = obj->buckets[req->hash % obj->nbuckets];
3055 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
3056 const Elf_Sym *symp;
3059 if (symnum >= obj->nchains)
3060 return (ESRCH); /* Bad object */
3062 symp = obj->symtab + symnum;
3063 strp = obj->strtab + symp->st_name;
3065 switch (ELF_ST_TYPE(symp->st_info)) {
3069 if (symp->st_value == 0)
3073 if (symp->st_shndx != SHN_UNDEF)
3076 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3077 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3084 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3087 if (req->ventry == NULL) {
3088 if (obj->versyms != NULL) {
3089 verndx = VER_NDX(obj->versyms[symnum]);
3090 if (verndx > obj->vernum) {
3091 _rtld_error("%s: symbol %s references wrong version %d",
3092 obj->path, obj->strtab + symnum, verndx);
3096 * If we are not called from dlsym (i.e. this is a normal
3097 * relocation from unversioned binary), accept the symbol
3098 * immediately if it happens to have first version after
3099 * this shared object became versioned. Otherwise, if
3100 * symbol is versioned and not hidden, remember it. If it
3101 * is the only symbol with this name exported by the
3102 * shared object, it will be returned as a match at the
3103 * end of the function. If symbol is global (verndx < 2)
3104 * accept it unconditionally.
3106 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3107 verndx == VER_NDX_GIVEN) {
3108 req->sym_out = symp;
3109 req->defobj_out = obj;
3112 else if (verndx >= VER_NDX_GIVEN) {
3113 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) {
3121 req->sym_out = symp;
3122 req->defobj_out = obj;
3125 if (obj->versyms == NULL) {
3126 if (object_match_name(obj, req->ventry->name)) {
3127 _rtld_error("%s: object %s should provide version %s for "
3128 "symbol %s", obj_rtld.path, obj->path,
3129 req->ventry->name, obj->strtab + symnum);
3133 verndx = VER_NDX(obj->versyms[symnum]);
3134 if (verndx > obj->vernum) {
3135 _rtld_error("%s: symbol %s references wrong version %d",
3136 obj->path, obj->strtab + symnum, verndx);
3139 if (obj->vertab[verndx].hash != req->ventry->hash ||
3140 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3142 * Version does not match. Look if this is a global symbol
3143 * and if it is not hidden. If global symbol (verndx < 2)
3144 * is available, use it. Do not return symbol if we are
3145 * called by dlvsym, because dlvsym looks for a specific
3146 * version and default one is not what dlvsym wants.
3148 if ((req->flags & SYMLOOK_DLSYM) ||
3149 (obj->versyms[symnum] & VER_NDX_HIDDEN) ||
3150 (verndx >= VER_NDX_GIVEN))
3154 req->sym_out = symp;
3155 req->defobj_out = obj;
3160 req->sym_out = vsymp;
3161 req->defobj_out = obj;
3168 trace_loaded_objects(Obj_Entry *obj)
3170 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
3173 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
3176 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
3177 fmt1 = "\t%o => %p (%x)\n";
3179 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
3180 fmt2 = "\t%o (%x)\n";
3182 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
3184 for (; obj; obj = obj->next) {
3185 Needed_Entry *needed;
3189 if (list_containers && obj->needed != NULL)
3190 printf("%s:\n", obj->path);
3191 for (needed = obj->needed; needed; needed = needed->next) {
3192 if (needed->obj != NULL) {
3193 if (needed->obj->traced && !list_containers)
3195 needed->obj->traced = true;
3196 path = needed->obj->path;
3200 name = (char *)obj->strtab + needed->name;
3201 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
3203 fmt = is_lib ? fmt1 : fmt2;
3204 while ((c = *fmt++) != '\0') {
3230 printf("%s", main_local);
3233 printf("%s", obj_main->path);
3240 printf("%d", sodp->sod_major);
3243 printf("%d", sodp->sod_minor);
3250 printf("%p", needed->obj ? needed->obj->mapbase : 0);
3262 * Unload a dlopened object and its dependencies from memory and from
3263 * our data structures. It is assumed that the DAG rooted in the
3264 * object has already been unreferenced, and that the object has a
3265 * reference count of 0.
3268 unload_object(Obj_Entry *root)
3273 assert(root->refcount == 0);
3276 * Pass over the DAG removing unreferenced objects from
3277 * appropriate lists.
3279 unlink_object(root);
3281 /* Unmap all objects that are no longer referenced. */
3282 linkp = &obj_list->next;
3283 while ((obj = *linkp) != NULL) {
3284 if (obj->refcount == 0) {
3285 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
3287 dbg("unloading \"%s\"", obj->path);
3288 unload_filtees(root);
3289 munmap(obj->mapbase, obj->mapsize);
3290 linkmap_delete(obj);
3301 unlink_object(Obj_Entry *root)
3305 if (root->refcount == 0) {
3306 /* Remove the object from the RTLD_GLOBAL list. */
3307 objlist_remove(&list_global, root);
3309 /* Remove the object from all objects' DAG lists. */
3310 STAILQ_FOREACH(elm, &root->dagmembers, link) {
3311 objlist_remove(&elm->obj->dldags, root);
3312 if (elm->obj != root)
3313 unlink_object(elm->obj);
3319 ref_dag(Obj_Entry *root)
3323 assert(root->dag_inited);
3324 STAILQ_FOREACH(elm, &root->dagmembers, link)
3325 elm->obj->refcount++;
3329 unref_dag(Obj_Entry *root)
3333 assert(root->dag_inited);
3334 STAILQ_FOREACH(elm, &root->dagmembers, link)
3335 elm->obj->refcount--;
3339 * Common code for MD __tls_get_addr().
3342 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset)
3344 Elf_Addr* dtv = *dtvp;
3345 RtldLockState lockstate;
3347 /* Check dtv generation in case new modules have arrived */
3348 if (dtv[0] != tls_dtv_generation) {
3352 wlock_acquire(rtld_bind_lock, &lockstate);
3353 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
3355 if (to_copy > tls_max_index)
3356 to_copy = tls_max_index;
3357 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
3358 newdtv[0] = tls_dtv_generation;
3359 newdtv[1] = tls_max_index;
3361 lock_release(rtld_bind_lock, &lockstate);
3365 /* Dynamically allocate module TLS if necessary */
3366 if (!dtv[index + 1]) {
3367 /* Signal safe, wlock will block out signals. */
3368 wlock_acquire(rtld_bind_lock, &lockstate);
3369 if (!dtv[index + 1])
3370 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
3371 lock_release(rtld_bind_lock, &lockstate);
3373 return (void*) (dtv[index + 1] + offset);
3376 /* XXX not sure what variants to use for arm. */
3378 #if defined(__ia64__) || defined(__powerpc__)
3381 * Allocate Static TLS using the Variant I method.
3384 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
3393 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
3396 assert(tcbsize >= TLS_TCB_SIZE);
3397 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
3398 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
3400 if (oldtcb != NULL) {
3401 memcpy(tls, oldtcb, tls_static_space);
3404 /* Adjust the DTV. */
3406 for (i = 0; i < dtv[1]; i++) {
3407 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
3408 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
3409 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
3413 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr));
3415 dtv[0] = tls_dtv_generation;
3416 dtv[1] = tls_max_index;
3418 for (obj = objs; obj; obj = obj->next) {
3419 if (obj->tlsoffset > 0) {
3420 addr = (Elf_Addr)tls + obj->tlsoffset;
3421 if (obj->tlsinitsize > 0)
3422 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
3423 if (obj->tlssize > obj->tlsinitsize)
3424 memset((void*) (addr + obj->tlsinitsize), 0,
3425 obj->tlssize - obj->tlsinitsize);
3426 dtv[obj->tlsindex + 1] = addr;
3435 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
3438 Elf_Addr tlsstart, tlsend;
3441 assert(tcbsize >= TLS_TCB_SIZE);
3443 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
3444 tlsend = tlsstart + tls_static_space;
3446 dtv = *(Elf_Addr **)tlsstart;
3448 for (i = 0; i < dtvsize; i++) {
3449 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
3450 free((void*)dtv[i+2]);
3459 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \
3460 defined(__arm__) || defined(__mips__)
3463 * Allocate Static TLS using the Variant II method.
3466 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
3471 Elf_Addr *dtv, *olddtv;
3472 Elf_Addr segbase, oldsegbase, addr;
3475 size = round(tls_static_space, tcbalign);
3477 assert(tcbsize >= 2*sizeof(Elf_Addr));
3478 tls = calloc(1, size + tcbsize);
3479 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
3481 segbase = (Elf_Addr)(tls + size);
3482 ((Elf_Addr*)segbase)[0] = segbase;
3483 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
3485 dtv[0] = tls_dtv_generation;
3486 dtv[1] = tls_max_index;
3490 * Copy the static TLS block over whole.
3492 oldsegbase = (Elf_Addr) oldtls;
3493 memcpy((void *)(segbase - tls_static_space),
3494 (const void *)(oldsegbase - tls_static_space),
3498 * If any dynamic TLS blocks have been created tls_get_addr(),
3501 olddtv = ((Elf_Addr**)oldsegbase)[1];
3502 for (i = 0; i < olddtv[1]; i++) {
3503 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
3504 dtv[i+2] = olddtv[i+2];
3510 * We assume that this block was the one we created with
3511 * allocate_initial_tls().
3513 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
3515 for (obj = objs; obj; obj = obj->next) {
3516 if (obj->tlsoffset) {
3517 addr = segbase - obj->tlsoffset;
3518 memset((void*) (addr + obj->tlsinitsize),
3519 0, obj->tlssize - obj->tlsinitsize);
3521 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
3522 dtv[obj->tlsindex + 1] = addr;
3527 return (void*) segbase;
3531 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
3536 Elf_Addr tlsstart, tlsend;
3539 * Figure out the size of the initial TLS block so that we can
3540 * find stuff which ___tls_get_addr() allocated dynamically.
3542 size = round(tls_static_space, tcbalign);
3544 dtv = ((Elf_Addr**)tls)[1];
3546 tlsend = (Elf_Addr) tls;
3547 tlsstart = tlsend - size;
3548 for (i = 0; i < dtvsize; i++) {
3549 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) {
3550 free((void*) dtv[i+2]);
3554 free((void*) tlsstart);
3561 * Allocate TLS block for module with given index.
3564 allocate_module_tls(int index)
3569 for (obj = obj_list; obj; obj = obj->next) {
3570 if (obj->tlsindex == index)
3574 _rtld_error("Can't find module with TLS index %d", index);
3578 p = malloc(obj->tlssize);
3580 _rtld_error("Cannot allocate TLS block for index %d", index);
3583 memcpy(p, obj->tlsinit, obj->tlsinitsize);
3584 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
3590 allocate_tls_offset(Obj_Entry *obj)
3597 if (obj->tlssize == 0) {
3598 obj->tls_done = true;
3602 if (obj->tlsindex == 1)
3603 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
3605 off = calculate_tls_offset(tls_last_offset, tls_last_size,
3606 obj->tlssize, obj->tlsalign);
3609 * If we have already fixed the size of the static TLS block, we
3610 * must stay within that size. When allocating the static TLS, we
3611 * leave a small amount of space spare to be used for dynamically
3612 * loading modules which use static TLS.
3614 if (tls_static_space) {
3615 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
3619 tls_last_offset = obj->tlsoffset = off;
3620 tls_last_size = obj->tlssize;
3621 obj->tls_done = true;
3627 free_tls_offset(Obj_Entry *obj)
3631 * If we were the last thing to allocate out of the static TLS
3632 * block, we give our space back to the 'allocator'. This is a
3633 * simplistic workaround to allow libGL.so.1 to be loaded and
3634 * unloaded multiple times.
3636 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
3637 == calculate_tls_end(tls_last_offset, tls_last_size)) {
3638 tls_last_offset -= obj->tlssize;
3644 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
3647 RtldLockState lockstate;
3649 wlock_acquire(rtld_bind_lock, &lockstate);
3650 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
3651 lock_release(rtld_bind_lock, &lockstate);
3656 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
3658 RtldLockState lockstate;
3660 wlock_acquire(rtld_bind_lock, &lockstate);
3661 free_tls(tcb, tcbsize, tcbalign);
3662 lock_release(rtld_bind_lock, &lockstate);
3666 object_add_name(Obj_Entry *obj, const char *name)
3672 entry = malloc(sizeof(Name_Entry) + len);
3674 if (entry != NULL) {
3675 strcpy(entry->name, name);
3676 STAILQ_INSERT_TAIL(&obj->names, entry, link);
3681 object_match_name(const Obj_Entry *obj, const char *name)
3685 STAILQ_FOREACH(entry, &obj->names, link) {
3686 if (strcmp(name, entry->name) == 0)
3693 locate_dependency(const Obj_Entry *obj, const char *name)
3695 const Objlist_Entry *entry;
3696 const Needed_Entry *needed;
3698 STAILQ_FOREACH(entry, &list_main, link) {
3699 if (object_match_name(entry->obj, name))
3703 for (needed = obj->needed; needed != NULL; needed = needed->next) {
3704 if (strcmp(obj->strtab + needed->name, name) == 0 ||
3705 (needed->obj != NULL && object_match_name(needed->obj, name))) {
3707 * If there is DT_NEEDED for the name we are looking for,
3708 * we are all set. Note that object might not be found if
3709 * dependency was not loaded yet, so the function can
3710 * return NULL here. This is expected and handled
3711 * properly by the caller.
3713 return (needed->obj);
3716 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
3722 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
3723 const Elf_Vernaux *vna)
3725 const Elf_Verdef *vd;
3726 const char *vername;
3728 vername = refobj->strtab + vna->vna_name;
3729 vd = depobj->verdef;
3731 _rtld_error("%s: version %s required by %s not defined",
3732 depobj->path, vername, refobj->path);
3736 if (vd->vd_version != VER_DEF_CURRENT) {
3737 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
3738 depobj->path, vd->vd_version);
3741 if (vna->vna_hash == vd->vd_hash) {
3742 const Elf_Verdaux *aux = (const Elf_Verdaux *)
3743 ((char *)vd + vd->vd_aux);
3744 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
3747 if (vd->vd_next == 0)
3749 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3751 if (vna->vna_flags & VER_FLG_WEAK)
3753 _rtld_error("%s: version %s required by %s not found",
3754 depobj->path, vername, refobj->path);
3759 rtld_verify_object_versions(Obj_Entry *obj)
3761 const Elf_Verneed *vn;
3762 const Elf_Verdef *vd;
3763 const Elf_Verdaux *vda;
3764 const Elf_Vernaux *vna;
3765 const Obj_Entry *depobj;
3766 int maxvernum, vernum;
3770 * Walk over defined and required version records and figure out
3771 * max index used by any of them. Do very basic sanity checking
3775 while (vn != NULL) {
3776 if (vn->vn_version != VER_NEED_CURRENT) {
3777 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
3778 obj->path, vn->vn_version);
3781 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
3783 vernum = VER_NEED_IDX(vna->vna_other);
3784 if (vernum > maxvernum)
3786 if (vna->vna_next == 0)
3788 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
3790 if (vn->vn_next == 0)
3792 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
3796 while (vd != NULL) {
3797 if (vd->vd_version != VER_DEF_CURRENT) {
3798 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
3799 obj->path, vd->vd_version);
3802 vernum = VER_DEF_IDX(vd->vd_ndx);
3803 if (vernum > maxvernum)
3805 if (vd->vd_next == 0)
3807 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3814 * Store version information in array indexable by version index.
3815 * Verify that object version requirements are satisfied along the
3818 obj->vernum = maxvernum + 1;
3819 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry));
3822 while (vd != NULL) {
3823 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
3824 vernum = VER_DEF_IDX(vd->vd_ndx);
3825 assert(vernum <= maxvernum);
3826 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
3827 obj->vertab[vernum].hash = vd->vd_hash;
3828 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
3829 obj->vertab[vernum].file = NULL;
3830 obj->vertab[vernum].flags = 0;
3832 if (vd->vd_next == 0)
3834 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3838 while (vn != NULL) {
3839 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
3842 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
3844 if (check_object_provided_version(obj, depobj, vna))
3846 vernum = VER_NEED_IDX(vna->vna_other);
3847 assert(vernum <= maxvernum);
3848 obj->vertab[vernum].hash = vna->vna_hash;
3849 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
3850 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
3851 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
3852 VER_INFO_HIDDEN : 0;
3853 if (vna->vna_next == 0)
3855 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
3857 if (vn->vn_next == 0)
3859 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
3865 rtld_verify_versions(const Objlist *objlist)
3867 Objlist_Entry *entry;
3871 STAILQ_FOREACH(entry, objlist, link) {
3873 * Skip dummy objects or objects that have their version requirements
3876 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
3878 if (rtld_verify_object_versions(entry->obj) == -1) {
3880 if (ld_tracing == NULL)
3884 if (rc == 0 || ld_tracing != NULL)
3885 rc = rtld_verify_object_versions(&obj_rtld);
3890 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
3895 vernum = VER_NDX(obj->versyms[symnum]);
3896 if (vernum >= obj->vernum) {
3897 _rtld_error("%s: symbol %s has wrong verneed value %d",
3898 obj->path, obj->strtab + symnum, vernum);
3899 } else if (obj->vertab[vernum].hash != 0) {
3900 return &obj->vertab[vernum];
3907 _rtld_get_stack_prot(void)
3910 return (stack_prot);
3914 map_stacks_exec(RtldLockState *lockstate)
3916 void (*thr_map_stacks_exec)(void);
3918 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
3920 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
3921 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
3922 if (thr_map_stacks_exec != NULL) {
3923 stack_prot |= PROT_EXEC;
3924 thr_map_stacks_exec();
3929 symlook_init(SymLook *dst, const char *name)
3932 bzero(dst, sizeof(*dst));
3934 dst->hash = elf_hash(name);
3938 symlook_init_from_req(SymLook *dst, const SymLook *src)
3941 dst->name = src->name;
3942 dst->hash = src->hash;
3943 dst->ventry = src->ventry;
3944 dst->flags = src->flags;
3945 dst->defobj_out = NULL;
3946 dst->sym_out = NULL;
3947 dst->lockstate = src->lockstate;
3951 * Overrides for libc_pic-provided functions.
3955 __getosreldate(void)
3965 oid[1] = KERN_OSRELDATE;
3967 len = sizeof(osrel);
3968 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
3969 if (error == 0 && osrel > 0 && len == sizeof(osrel))
3975 * No unresolved symbols for rtld.
3978 __pthread_cxa_finalize(struct dl_phdr_info *a)