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>
63 #include "rtld_printf.h"
67 #define PATH_RTLD "/libexec/ld-elf.so.1"
69 #define PATH_RTLD "/libexec/ld-elf32.so.1"
73 typedef void (*func_ptr_type)();
74 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
77 * Function declarations.
79 static const char *basename(const char *);
80 static void die(void) __dead2;
81 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
83 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *);
84 static void digest_dynamic(Obj_Entry *, int);
85 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
86 static Obj_Entry *dlcheck(void *);
87 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
88 int lo_flags, int mode);
89 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
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_rtld(caddr_t, Elf_Auxinfo **);
99 static void initlist_add_neededs(Needed_Entry *, Objlist *);
100 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
101 static void linkmap_add(Obj_Entry *);
102 static void linkmap_delete(Obj_Entry *);
103 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
104 static void unload_filtees(Obj_Entry *);
105 static int load_needed_objects(Obj_Entry *, int);
106 static int load_preload_objects(void);
107 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
108 static void map_stacks_exec(RtldLockState *);
109 static Obj_Entry *obj_from_addr(const void *);
110 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
111 static void objlist_call_init(Objlist *, RtldLockState *);
112 static void objlist_clear(Objlist *);
113 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
114 static void objlist_init(Objlist *);
115 static void objlist_push_head(Objlist *, Obj_Entry *);
116 static void objlist_push_tail(Objlist *, Obj_Entry *);
117 static void objlist_remove(Objlist *, Obj_Entry *);
118 static void *path_enumerate(const char *, path_enum_proc, void *);
119 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
121 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
122 int flags, RtldLockState *lockstate);
123 static int rtld_dirname(const char *, char *);
124 static int rtld_dirname_abs(const char *, char *);
125 static void *rtld_dlopen(const char *name, int fd, int mode);
126 static void rtld_exit(void);
127 static char *search_library_path(const char *, const char *);
128 static const void **get_program_var_addr(const char *, RtldLockState *);
129 static void set_program_var(const char *, const void *);
130 static int symlook_default(SymLook *, const Obj_Entry *refobj);
131 static int symlook_global(SymLook *, DoneList *);
132 static void symlook_init_from_req(SymLook *, const SymLook *);
133 static int symlook_list(SymLook *, const Objlist *, DoneList *);
134 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
135 static int symlook_obj1(SymLook *, const Obj_Entry *);
136 static void trace_loaded_objects(Obj_Entry *);
137 static void unlink_object(Obj_Entry *);
138 static void unload_object(Obj_Entry *);
139 static void unref_dag(Obj_Entry *);
140 static void ref_dag(Obj_Entry *);
141 static int origin_subst_one(char **, const char *, const char *,
142 const char *, char *);
143 static char *origin_subst(const char *, const char *);
144 static void preinit_main(void);
145 static int rtld_verify_versions(const Objlist *);
146 static int rtld_verify_object_versions(Obj_Entry *);
147 static void object_add_name(Obj_Entry *, const char *);
148 static int object_match_name(const Obj_Entry *, const char *);
149 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
150 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
151 struct dl_phdr_info *phdr_info);
153 void r_debug_state(struct r_debug *, struct link_map *) __noinline;
158 static char *error_message; /* Message for dlerror(), or NULL */
159 struct r_debug r_debug; /* for GDB; */
160 static bool libmap_disable; /* Disable libmap */
161 static bool ld_loadfltr; /* Immediate filters processing */
162 static char *libmap_override; /* Maps to use in addition to libmap.conf */
163 static bool trust; /* False for setuid and setgid programs */
164 static bool dangerous_ld_env; /* True if environment variables have been
165 used to affect the libraries loaded */
166 static char *ld_bind_now; /* Environment variable for immediate binding */
167 static char *ld_debug; /* Environment variable for debugging */
168 static char *ld_library_path; /* Environment variable for search path */
169 static char *ld_preload; /* Environment variable for libraries to
171 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
172 static char *ld_tracing; /* Called from ldd to print libs */
173 static char *ld_utrace; /* Use utrace() to log events. */
174 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
175 static Obj_Entry **obj_tail; /* Link field of last object in list */
176 static Obj_Entry *obj_main; /* The main program shared object */
177 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
178 static unsigned int obj_count; /* Number of objects in obj_list */
179 static unsigned int obj_loads; /* Number of objects in obj_list */
181 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
182 STAILQ_HEAD_INITIALIZER(list_global);
183 static Objlist list_main = /* Objects loaded at program startup */
184 STAILQ_HEAD_INITIALIZER(list_main);
185 static Objlist list_fini = /* Objects needing fini() calls */
186 STAILQ_HEAD_INITIALIZER(list_fini);
188 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
190 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
192 extern Elf_Dyn _DYNAMIC;
193 #pragma weak _DYNAMIC
194 #ifndef RTLD_IS_DYNAMIC
195 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
198 int osreldate, pagesize;
200 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
202 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
203 static int max_stack_flags;
206 * Global declarations normally provided by crt1. The dynamic linker is
207 * not built with crt1, so we have to provide them ourselves.
213 * Used to pass argc, argv to init functions.
219 * Globals to control TLS allocation.
221 size_t tls_last_offset; /* Static TLS offset of last module */
222 size_t tls_last_size; /* Static TLS size of last module */
223 size_t tls_static_space; /* Static TLS space allocated */
224 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
225 int tls_max_index = 1; /* Largest module index allocated */
228 * Fill in a DoneList with an allocation large enough to hold all of
229 * the currently-loaded objects. Keep this as a macro since it calls
230 * alloca and we want that to occur within the scope of the caller.
232 #define donelist_init(dlp) \
233 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
234 assert((dlp)->objs != NULL), \
235 (dlp)->num_alloc = obj_count, \
238 #define UTRACE_DLOPEN_START 1
239 #define UTRACE_DLOPEN_STOP 2
240 #define UTRACE_DLCLOSE_START 3
241 #define UTRACE_DLCLOSE_STOP 4
242 #define UTRACE_LOAD_OBJECT 5
243 #define UTRACE_UNLOAD_OBJECT 6
244 #define UTRACE_ADD_RUNDEP 7
245 #define UTRACE_PRELOAD_FINISHED 8
246 #define UTRACE_INIT_CALL 9
247 #define UTRACE_FINI_CALL 10
250 char sig[4]; /* 'RTLD' */
253 void *mapbase; /* Used for 'parent' and 'init/fini' */
255 int refcnt; /* Used for 'mode' */
256 char name[MAXPATHLEN];
259 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
260 if (ld_utrace != NULL) \
261 ld_utrace_log(e, h, mb, ms, r, n); \
265 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
266 int refcnt, const char *name)
268 struct utrace_rtld ut;
276 ut.mapbase = mapbase;
277 ut.mapsize = mapsize;
279 bzero(ut.name, sizeof(ut.name));
281 strlcpy(ut.name, name, sizeof(ut.name));
282 utrace(&ut, sizeof(ut));
286 * Main entry point for dynamic linking. The first argument is the
287 * stack pointer. The stack is expected to be laid out as described
288 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
289 * Specifically, the stack pointer points to a word containing
290 * ARGC. Following that in the stack is a null-terminated sequence
291 * of pointers to argument strings. Then comes a null-terminated
292 * sequence of pointers to environment strings. Finally, there is a
293 * sequence of "auxiliary vector" entries.
295 * The second argument points to a place to store the dynamic linker's
296 * exit procedure pointer and the third to a place to store the main
299 * The return value is the main program's entry point.
302 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
304 Elf_Auxinfo *aux_info[AT_COUNT];
312 Objlist_Entry *entry;
314 Obj_Entry **preload_tail;
316 RtldLockState lockstate;
321 * On entry, the dynamic linker itself has not been relocated yet.
322 * Be very careful not to reference any global data until after
323 * init_rtld has returned. It is OK to reference file-scope statics
324 * and string constants, and to call static and global functions.
327 /* Find the auxiliary vector on the stack. */
330 sp += argc + 1; /* Skip over arguments and NULL terminator */
332 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
334 aux = (Elf_Auxinfo *) sp;
336 /* Digest the auxiliary vector. */
337 for (i = 0; i < AT_COUNT; i++)
339 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
340 if (auxp->a_type < AT_COUNT)
341 aux_info[auxp->a_type] = auxp;
344 /* Initialize and relocate ourselves. */
345 assert(aux_info[AT_BASE] != NULL);
346 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
348 __progname = obj_rtld.path;
349 argv0 = argv[0] != NULL ? argv[0] : "(null)";
354 if (aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
355 i = aux_info[AT_CANARYLEN]->a_un.a_val;
356 if (i > sizeof(__stack_chk_guard))
357 i = sizeof(__stack_chk_guard);
358 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
363 len = sizeof(__stack_chk_guard);
364 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
365 len != sizeof(__stack_chk_guard)) {
366 /* If sysctl was unsuccessful, use the "terminator canary". */
367 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
368 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
369 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
370 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
374 trust = !issetugid();
376 ld_bind_now = getenv(LD_ "BIND_NOW");
378 * If the process is tainted, then we un-set the dangerous environment
379 * variables. The process will be marked as tainted until setuid(2)
380 * is called. If any child process calls setuid(2) we do not want any
381 * future processes to honor the potentially un-safe variables.
384 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
385 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") ||
386 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
387 unsetenv(LD_ "LOADFLTR")) {
388 _rtld_error("environment corrupt; aborting");
392 ld_debug = getenv(LD_ "DEBUG");
393 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
394 libmap_override = getenv(LD_ "LIBMAP");
395 ld_library_path = getenv(LD_ "LIBRARY_PATH");
396 ld_preload = getenv(LD_ "PRELOAD");
397 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
398 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
399 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
400 (ld_library_path != NULL) || (ld_preload != NULL) ||
401 (ld_elf_hints_path != NULL) || ld_loadfltr;
402 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
403 ld_utrace = getenv(LD_ "UTRACE");
405 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
406 ld_elf_hints_path = _PATH_ELF_HINTS;
408 if (ld_debug != NULL && *ld_debug != '\0')
410 dbg("%s is initialized, base address = %p", __progname,
411 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
412 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
413 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
415 dbg("initializing thread locks");
419 * Load the main program, or process its program header if it is
422 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
423 int fd = aux_info[AT_EXECFD]->a_un.a_val;
424 dbg("loading main program");
425 obj_main = map_object(fd, argv0, NULL);
427 if (obj_main == NULL)
429 max_stack_flags = obj->stack_flags;
430 } else { /* Main program already loaded. */
431 const Elf_Phdr *phdr;
435 dbg("processing main program's program header");
436 assert(aux_info[AT_PHDR] != NULL);
437 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
438 assert(aux_info[AT_PHNUM] != NULL);
439 phnum = aux_info[AT_PHNUM]->a_un.a_val;
440 assert(aux_info[AT_PHENT] != NULL);
441 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
442 assert(aux_info[AT_ENTRY] != NULL);
443 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
444 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
448 if (aux_info[AT_EXECPATH] != 0) {
450 char buf[MAXPATHLEN];
452 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
453 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
454 if (kexecpath[0] == '/')
455 obj_main->path = kexecpath;
456 else if (getcwd(buf, sizeof(buf)) == NULL ||
457 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
458 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
459 obj_main->path = xstrdup(argv0);
461 obj_main->path = xstrdup(buf);
463 dbg("No AT_EXECPATH");
464 obj_main->path = xstrdup(argv0);
466 dbg("obj_main path %s", obj_main->path);
467 obj_main->mainprog = true;
469 if (aux_info[AT_STACKPROT] != NULL &&
470 aux_info[AT_STACKPROT]->a_un.a_val != 0)
471 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
474 * Get the actual dynamic linker pathname from the executable if
475 * possible. (It should always be possible.) That ensures that
476 * gdb will find the right dynamic linker even if a non-standard
479 if (obj_main->interp != NULL &&
480 strcmp(obj_main->interp, obj_rtld.path) != 0) {
482 obj_rtld.path = xstrdup(obj_main->interp);
483 __progname = obj_rtld.path;
486 digest_dynamic(obj_main, 0);
488 linkmap_add(obj_main);
489 linkmap_add(&obj_rtld);
491 /* Link the main program into the list of objects. */
492 *obj_tail = obj_main;
493 obj_tail = &obj_main->next;
497 /* Initialize a fake symbol for resolving undefined weak references. */
498 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
499 sym_zero.st_shndx = SHN_UNDEF;
500 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
503 libmap_disable = (bool)lm_init(libmap_override);
505 dbg("loading LD_PRELOAD libraries");
506 if (load_preload_objects() == -1)
508 preload_tail = obj_tail;
510 dbg("loading needed objects");
511 if (load_needed_objects(obj_main, 0) == -1)
514 /* Make a list of all objects loaded at startup. */
515 for (obj = obj_list; obj != NULL; obj = obj->next) {
516 objlist_push_tail(&list_main, obj);
520 dbg("checking for required versions");
521 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
524 if (ld_tracing) { /* We're done */
525 trace_loaded_objects(obj_main);
529 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
530 dump_relocations(obj_main);
535 * Processing tls relocations requires having the tls offsets
536 * initialized. Prepare offsets before starting initial
537 * relocation processing.
539 dbg("initializing initial thread local storage offsets");
540 STAILQ_FOREACH(entry, &list_main, link) {
542 * Allocate all the initial objects out of the static TLS
543 * block even if they didn't ask for it.
545 allocate_tls_offset(entry->obj);
548 if (relocate_objects(obj_main,
549 ld_bind_now != NULL && *ld_bind_now != '\0',
550 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
553 dbg("doing copy relocations");
554 if (do_copy_relocations(obj_main) == -1)
557 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
558 dump_relocations(obj_main);
563 * Setup TLS for main thread. This must be done after the
564 * relocations are processed, since tls initialization section
565 * might be the subject for relocations.
567 dbg("initializing initial thread local storage");
568 allocate_initial_tls(obj_list);
570 dbg("initializing key program variables");
571 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
572 set_program_var("environ", env);
573 set_program_var("__elf_aux_vector", aux);
575 /* Make a list of init functions to call. */
576 objlist_init(&initlist);
577 initlist_add_objects(obj_list, preload_tail, &initlist);
579 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
581 map_stacks_exec(NULL);
583 dbg("resolving ifuncs");
584 if (resolve_objects_ifunc(obj_main,
585 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
589 if (!obj_main->crt_no_init) {
591 * Make sure we don't call the main program's init and fini
592 * functions for binaries linked with old crt1 which calls
595 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
596 obj_main->preinit_array = obj_main->init_array =
597 obj_main->fini_array = (Elf_Addr)NULL;
600 wlock_acquire(rtld_bind_lock, &lockstate);
601 if (obj_main->crt_no_init)
603 objlist_call_init(&initlist, &lockstate);
604 objlist_clear(&initlist);
605 dbg("loading filtees");
606 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
607 if (ld_loadfltr || obj->z_loadfltr)
608 load_filtees(obj, 0, &lockstate);
610 lock_release(rtld_bind_lock, &lockstate);
612 dbg("transferring control to program entry point = %p", obj_main->entry);
614 /* Return the exit procedure and the program entry point. */
615 *exit_proc = rtld_exit;
617 return (func_ptr_type) obj_main->entry;
621 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
626 ptr = (void *)make_function_pointer(def, obj);
627 target = ((Elf_Addr (*)(void))ptr)();
628 return ((void *)target);
632 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
636 const Obj_Entry *defobj;
639 RtldLockState lockstate;
641 rlock_acquire(rtld_bind_lock, &lockstate);
642 if (sigsetjmp(lockstate.env, 0) != 0)
643 lock_upgrade(rtld_bind_lock, &lockstate);
645 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
647 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
649 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
650 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
654 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
655 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
657 target = (Elf_Addr)(defobj->relocbase + def->st_value);
659 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
660 defobj->strtab + def->st_name, basename(obj->path),
661 (void *)target, basename(defobj->path));
664 * Write the new contents for the jmpslot. Note that depending on
665 * architecture, the value which we need to return back to the
666 * lazy binding trampoline may or may not be the target
667 * address. The value returned from reloc_jmpslot() is the value
668 * that the trampoline needs.
670 target = reloc_jmpslot(where, target, defobj, obj, rel);
671 lock_release(rtld_bind_lock, &lockstate);
676 * Error reporting function. Use it like printf. If formats the message
677 * into a buffer, and sets things up so that the next call to dlerror()
678 * will return the message.
681 _rtld_error(const char *fmt, ...)
683 static char buf[512];
687 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
693 * Return a dynamically-allocated copy of the current error message, if any.
698 return error_message == NULL ? NULL : xstrdup(error_message);
702 * Restore the current error message from a copy which was previously saved
703 * by errmsg_save(). The copy is freed.
706 errmsg_restore(char *saved_msg)
708 if (saved_msg == NULL)
709 error_message = NULL;
711 _rtld_error("%s", saved_msg);
717 basename(const char *name)
719 const char *p = strrchr(name, '/');
720 return p != NULL ? p + 1 : name;
723 static struct utsname uts;
726 origin_subst_one(char **res, const char *real, const char *kw, const char *subst,
736 subst_len = kw_len = 0;
740 if (subst_len == 0) {
741 subst_len = strlen(subst);
745 *res = xmalloc(PATH_MAX);
748 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) {
749 _rtld_error("Substitution of %s in %s cannot be performed",
751 if (may_free != NULL)
756 memcpy(res1, p, p1 - p);
758 memcpy(res1, subst, subst_len);
763 if (may_free != NULL)
766 *res = xstrdup(real);
770 if (may_free != NULL)
772 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) {
782 origin_subst(const char *real, const char *origin_path)
784 char *res1, *res2, *res3, *res4;
786 if (uts.sysname[0] == '\0') {
787 if (uname(&uts) != 0) {
788 _rtld_error("utsname failed: %d", errno);
792 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) ||
793 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) ||
794 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) ||
795 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3))
803 const char *msg = dlerror();
807 rtld_fdputstr(STDERR_FILENO, msg);
808 rtld_fdputchar(STDERR_FILENO, '\n');
813 * Process a shared object's DYNAMIC section, and save the important
814 * information in its Obj_Entry structure.
817 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
818 const Elf_Dyn **dyn_soname)
821 Needed_Entry **needed_tail = &obj->needed;
822 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
823 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
824 int plttype = DT_REL;
829 obj->bind_now = false;
830 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
831 switch (dynp->d_tag) {
834 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
838 obj->relsize = dynp->d_un.d_val;
842 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
846 obj->pltrel = (const Elf_Rel *)
847 (obj->relocbase + dynp->d_un.d_ptr);
851 obj->pltrelsize = dynp->d_un.d_val;
855 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
859 obj->relasize = dynp->d_un.d_val;
863 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
867 plttype = dynp->d_un.d_val;
868 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
872 obj->symtab = (const Elf_Sym *)
873 (obj->relocbase + dynp->d_un.d_ptr);
877 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
881 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
885 obj->strsize = dynp->d_un.d_val;
889 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
894 obj->verneednum = dynp->d_un.d_val;
898 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
903 obj->verdefnum = dynp->d_un.d_val;
907 obj->versyms = (const Elf_Versym *)(obj->relocbase +
913 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
914 (obj->relocbase + dynp->d_un.d_ptr);
915 obj->nbuckets = hashtab[0];
916 obj->nchains = hashtab[1];
917 obj->buckets = hashtab + 2;
918 obj->chains = obj->buckets + obj->nbuckets;
924 Needed_Entry *nep = NEW(Needed_Entry);
925 nep->name = dynp->d_un.d_val;
930 needed_tail = &nep->next;
936 Needed_Entry *nep = NEW(Needed_Entry);
937 nep->name = dynp->d_un.d_val;
941 *needed_filtees_tail = nep;
942 needed_filtees_tail = &nep->next;
948 Needed_Entry *nep = NEW(Needed_Entry);
949 nep->name = dynp->d_un.d_val;
953 *needed_aux_filtees_tail = nep;
954 needed_aux_filtees_tail = &nep->next;
959 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
967 obj->symbolic = true;
971 case DT_RUNPATH: /* XXX: process separately */
973 * We have to wait until later to process this, because we
974 * might not have gotten the address of the string table yet.
984 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
987 case DT_PREINIT_ARRAY:
988 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
991 case DT_PREINIT_ARRAYSZ:
992 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
996 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
999 case DT_INIT_ARRAYSZ:
1000 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1004 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1008 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1011 case DT_FINI_ARRAYSZ:
1012 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1016 * Don't process DT_DEBUG on MIPS as the dynamic section
1017 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1022 /* XXX - not implemented yet */
1024 dbg("Filling in DT_DEBUG entry");
1025 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1030 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1031 obj->z_origin = true;
1032 if (dynp->d_un.d_val & DF_SYMBOLIC)
1033 obj->symbolic = true;
1034 if (dynp->d_un.d_val & DF_TEXTREL)
1035 obj->textrel = true;
1036 if (dynp->d_un.d_val & DF_BIND_NOW)
1037 obj->bind_now = true;
1038 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1042 case DT_MIPS_LOCAL_GOTNO:
1043 obj->local_gotno = dynp->d_un.d_val;
1046 case DT_MIPS_SYMTABNO:
1047 obj->symtabno = dynp->d_un.d_val;
1050 case DT_MIPS_GOTSYM:
1051 obj->gotsym = dynp->d_un.d_val;
1054 case DT_MIPS_RLD_MAP:
1057 dbg("Filling in DT_DEBUG entry");
1058 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1064 if (dynp->d_un.d_val & DF_1_NOOPEN)
1065 obj->z_noopen = true;
1066 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1067 obj->z_origin = true;
1068 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1070 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1071 obj->bind_now = true;
1072 if (dynp->d_un.d_val & DF_1_NODELETE)
1073 obj->z_nodelete = true;
1074 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1075 obj->z_loadfltr = true;
1080 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1087 obj->traced = false;
1089 if (plttype == DT_RELA) {
1090 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1092 obj->pltrelasize = obj->pltrelsize;
1093 obj->pltrelsize = 0;
1098 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1099 const Elf_Dyn *dyn_soname)
1102 if (obj->z_origin && obj->origin_path == NULL) {
1103 obj->origin_path = xmalloc(PATH_MAX);
1104 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1108 if (dyn_rpath != NULL) {
1109 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1111 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1114 if (dyn_soname != NULL)
1115 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1119 digest_dynamic(Obj_Entry *obj, int early)
1121 const Elf_Dyn *dyn_rpath;
1122 const Elf_Dyn *dyn_soname;
1124 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname);
1125 digest_dynamic2(obj, dyn_rpath, dyn_soname);
1129 * Process a shared object's program header. This is used only for the
1130 * main program, when the kernel has already loaded the main program
1131 * into memory before calling the dynamic linker. It creates and
1132 * returns an Obj_Entry structure.
1135 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1138 const Elf_Phdr *phlimit = phdr + phnum;
1140 Elf_Addr note_start, note_end;
1144 for (ph = phdr; ph < phlimit; ph++) {
1145 if (ph->p_type != PT_PHDR)
1149 obj->phsize = ph->p_memsz;
1150 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1154 obj->stack_flags = PF_X | PF_R | PF_W;
1156 for (ph = phdr; ph < phlimit; ph++) {
1157 switch (ph->p_type) {
1160 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1164 if (nsegs == 0) { /* First load segment */
1165 obj->vaddrbase = trunc_page(ph->p_vaddr);
1166 obj->mapbase = obj->vaddrbase + obj->relocbase;
1167 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1169 } else { /* Last load segment */
1170 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1177 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1182 obj->tlssize = ph->p_memsz;
1183 obj->tlsalign = ph->p_align;
1184 obj->tlsinitsize = ph->p_filesz;
1185 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1189 obj->stack_flags = ph->p_flags;
1193 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1194 obj->relro_size = round_page(ph->p_memsz);
1198 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1199 note_end = note_start + ph->p_filesz;
1200 digest_notes(obj, note_start, note_end);
1205 _rtld_error("%s: too few PT_LOAD segments", path);
1214 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1216 const Elf_Note *note;
1217 const char *note_name;
1220 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1221 note = (const Elf_Note *)((const char *)(note + 1) +
1222 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1223 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1224 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1225 note->n_descsz != sizeof(int32_t))
1227 if (note->n_type != ABI_NOTETYPE &&
1228 note->n_type != CRT_NOINIT_NOTETYPE)
1230 note_name = (const char *)(note + 1);
1231 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1232 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1234 switch (note->n_type) {
1236 /* FreeBSD osrel note */
1237 p = (uintptr_t)(note + 1);
1238 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1239 obj->osrel = *(const int32_t *)(p);
1240 dbg("note osrel %d", obj->osrel);
1242 case CRT_NOINIT_NOTETYPE:
1243 /* FreeBSD 'crt does not call init' note */
1244 obj->crt_no_init = true;
1245 dbg("note crt_no_init");
1252 dlcheck(void *handle)
1256 for (obj = obj_list; obj != NULL; obj = obj->next)
1257 if (obj == (Obj_Entry *) handle)
1260 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1261 _rtld_error("Invalid shared object handle %p", handle);
1268 * If the given object is already in the donelist, return true. Otherwise
1269 * add the object to the list and return false.
1272 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1276 for (i = 0; i < dlp->num_used; i++)
1277 if (dlp->objs[i] == obj)
1280 * Our donelist allocation should always be sufficient. But if
1281 * our threads locking isn't working properly, more shared objects
1282 * could have been loaded since we allocated the list. That should
1283 * never happen, but we'll handle it properly just in case it does.
1285 if (dlp->num_used < dlp->num_alloc)
1286 dlp->objs[dlp->num_used++] = obj;
1291 * Hash function for symbol table lookup. Don't even think about changing
1292 * this. It is specified by the System V ABI.
1295 elf_hash(const char *name)
1297 const unsigned char *p = (const unsigned char *) name;
1298 unsigned long h = 0;
1301 while (*p != '\0') {
1302 h = (h << 4) + *p++;
1303 if ((g = h & 0xf0000000) != 0)
1311 * Find the library with the given name, and return its full pathname.
1312 * The returned string is dynamically allocated. Generates an error
1313 * message and returns NULL if the library cannot be found.
1315 * If the second argument is non-NULL, then it refers to an already-
1316 * loaded shared object, whose library search path will be searched.
1318 * The search order is:
1320 * rpath in the referencing file
1325 find_library(const char *xname, const Obj_Entry *refobj)
1330 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1331 if (xname[0] != '/' && !trust) {
1332 _rtld_error("Absolute pathname required for shared object \"%s\"",
1336 if (refobj != NULL && refobj->z_origin)
1337 return origin_subst(xname, refobj->origin_path);
1339 return xstrdup(xname);
1342 if (libmap_disable || (refobj == NULL) ||
1343 (name = lm_find(refobj->path, xname)) == NULL)
1344 name = (char *)xname;
1346 dbg(" Searching for \"%s\"", name);
1348 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1350 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1351 (pathname = search_library_path(name, gethints())) != NULL ||
1352 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1355 if(refobj != NULL && refobj->path != NULL) {
1356 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1357 name, basename(refobj->path));
1359 _rtld_error("Shared object \"%s\" not found", name);
1365 * Given a symbol number in a referencing object, find the corresponding
1366 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1367 * no definition was found. Returns a pointer to the Obj_Entry of the
1368 * defining object via the reference parameter DEFOBJ_OUT.
1371 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1372 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1373 RtldLockState *lockstate)
1377 const Obj_Entry *defobj;
1383 * If we have already found this symbol, get the information from
1386 if (symnum >= refobj->nchains)
1387 return NULL; /* Bad object */
1388 if (cache != NULL && cache[symnum].sym != NULL) {
1389 *defobj_out = cache[symnum].obj;
1390 return cache[symnum].sym;
1393 ref = refobj->symtab + symnum;
1394 name = refobj->strtab + ref->st_name;
1399 * We don't have to do a full scale lookup if the symbol is local.
1400 * We know it will bind to the instance in this load module; to
1401 * which we already have a pointer (ie ref). By not doing a lookup,
1402 * we not only improve performance, but it also avoids unresolvable
1403 * symbols when local symbols are not in the hash table. This has
1404 * been seen with the ia64 toolchain.
1406 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1407 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1408 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1411 symlook_init(&req, name);
1413 req.ventry = fetch_ventry(refobj, symnum);
1414 req.lockstate = lockstate;
1415 res = symlook_default(&req, refobj);
1418 defobj = req.defobj_out;
1426 * If we found no definition and the reference is weak, treat the
1427 * symbol as having the value zero.
1429 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1435 *defobj_out = defobj;
1436 /* Record the information in the cache to avoid subsequent lookups. */
1437 if (cache != NULL) {
1438 cache[symnum].sym = def;
1439 cache[symnum].obj = defobj;
1442 if (refobj != &obj_rtld)
1443 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1449 * Return the search path from the ldconfig hints file, reading it if
1450 * necessary. Returns NULL if there are problems with the hints file,
1451 * or if the search path there is empty.
1458 if (hints == NULL) {
1460 struct elfhints_hdr hdr;
1463 /* Keep from trying again in case the hints file is bad. */
1466 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1)
1468 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1469 hdr.magic != ELFHINTS_MAGIC ||
1474 p = xmalloc(hdr.dirlistlen + 1);
1475 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1476 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) {
1484 return hints[0] != '\0' ? hints : NULL;
1488 init_dag(Obj_Entry *root)
1490 const Needed_Entry *needed;
1491 const Objlist_Entry *elm;
1494 if (root->dag_inited)
1496 donelist_init(&donelist);
1498 /* Root object belongs to own DAG. */
1499 objlist_push_tail(&root->dldags, root);
1500 objlist_push_tail(&root->dagmembers, root);
1501 donelist_check(&donelist, root);
1504 * Add dependencies of root object to DAG in breadth order
1505 * by exploiting the fact that each new object get added
1506 * to the tail of the dagmembers list.
1508 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1509 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1510 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1512 objlist_push_tail(&needed->obj->dldags, root);
1513 objlist_push_tail(&root->dagmembers, needed->obj);
1516 root->dag_inited = true;
1520 * Initialize the dynamic linker. The argument is the address at which
1521 * the dynamic linker has been mapped into memory. The primary task of
1522 * this function is to relocate the dynamic linker.
1525 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1527 Obj_Entry objtmp; /* Temporary rtld object */
1528 const Elf_Dyn *dyn_rpath;
1529 const Elf_Dyn *dyn_soname;
1532 * Conjure up an Obj_Entry structure for the dynamic linker.
1534 * The "path" member can't be initialized yet because string constants
1535 * cannot yet be accessed. Below we will set it correctly.
1537 memset(&objtmp, 0, sizeof(objtmp));
1540 objtmp.mapbase = mapbase;
1542 objtmp.relocbase = mapbase;
1544 if (RTLD_IS_DYNAMIC()) {
1545 objtmp.dynamic = rtld_dynamic(&objtmp);
1546 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname);
1547 assert(objtmp.needed == NULL);
1548 #if !defined(__mips__)
1549 /* MIPS has a bogus DT_TEXTREL. */
1550 assert(!objtmp.textrel);
1554 * Temporarily put the dynamic linker entry into the object list, so
1555 * that symbols can be found.
1558 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1561 /* Initialize the object list. */
1562 obj_tail = &obj_list;
1564 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1565 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1567 if (aux_info[AT_PAGESZ] != NULL)
1568 pagesize = aux_info[AT_PAGESZ]->a_un.a_val;
1569 if (aux_info[AT_OSRELDATE] != NULL)
1570 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1572 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname);
1574 /* Replace the path with a dynamically allocated copy. */
1575 obj_rtld.path = xstrdup(PATH_RTLD);
1577 r_debug.r_brk = r_debug_state;
1578 r_debug.r_state = RT_CONSISTENT;
1582 * Add the init functions from a needed object list (and its recursive
1583 * needed objects) to "list". This is not used directly; it is a helper
1584 * function for initlist_add_objects(). The write lock must be held
1585 * when this function is called.
1588 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1590 /* Recursively process the successor needed objects. */
1591 if (needed->next != NULL)
1592 initlist_add_neededs(needed->next, list);
1594 /* Process the current needed object. */
1595 if (needed->obj != NULL)
1596 initlist_add_objects(needed->obj, &needed->obj->next, list);
1600 * Scan all of the DAGs rooted in the range of objects from "obj" to
1601 * "tail" and add their init functions to "list". This recurses over
1602 * the DAGs and ensure the proper init ordering such that each object's
1603 * needed libraries are initialized before the object itself. At the
1604 * same time, this function adds the objects to the global finalization
1605 * list "list_fini" in the opposite order. The write lock must be
1606 * held when this function is called.
1609 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1612 if (obj->init_scanned || obj->init_done)
1614 obj->init_scanned = true;
1616 /* Recursively process the successor objects. */
1617 if (&obj->next != tail)
1618 initlist_add_objects(obj->next, tail, list);
1620 /* Recursively process the needed objects. */
1621 if (obj->needed != NULL)
1622 initlist_add_neededs(obj->needed, list);
1623 if (obj->needed_filtees != NULL)
1624 initlist_add_neededs(obj->needed_filtees, list);
1625 if (obj->needed_aux_filtees != NULL)
1626 initlist_add_neededs(obj->needed_aux_filtees, list);
1628 /* Add the object to the init list. */
1629 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1630 obj->init_array != (Elf_Addr)NULL)
1631 objlist_push_tail(list, obj);
1633 /* Add the object to the global fini list in the reverse order. */
1634 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1635 && !obj->on_fini_list) {
1636 objlist_push_head(&list_fini, obj);
1637 obj->on_fini_list = true;
1642 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1646 free_needed_filtees(Needed_Entry *n)
1648 Needed_Entry *needed, *needed1;
1650 for (needed = n; needed != NULL; needed = needed->next) {
1651 if (needed->obj != NULL) {
1652 dlclose(needed->obj);
1656 for (needed = n; needed != NULL; needed = needed1) {
1657 needed1 = needed->next;
1663 unload_filtees(Obj_Entry *obj)
1666 free_needed_filtees(obj->needed_filtees);
1667 obj->needed_filtees = NULL;
1668 free_needed_filtees(obj->needed_aux_filtees);
1669 obj->needed_aux_filtees = NULL;
1670 obj->filtees_loaded = false;
1674 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags)
1677 for (; needed != NULL; needed = needed->next) {
1678 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
1679 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
1685 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
1688 lock_restart_for_upgrade(lockstate);
1689 if (!obj->filtees_loaded) {
1690 load_filtee1(obj, obj->needed_filtees, flags);
1691 load_filtee1(obj, obj->needed_aux_filtees, flags);
1692 obj->filtees_loaded = true;
1697 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
1701 for (; needed != NULL; needed = needed->next) {
1702 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
1703 flags & ~RTLD_LO_NOLOAD);
1704 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
1706 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) {
1707 dbg("obj %s nodelete", obj1->path);
1710 obj1->ref_nodel = true;
1717 * Given a shared object, traverse its list of needed objects, and load
1718 * each of them. Returns 0 on success. Generates an error message and
1719 * returns -1 on failure.
1722 load_needed_objects(Obj_Entry *first, int flags)
1726 for (obj = first; obj != NULL; obj = obj->next) {
1727 if (process_needed(obj, obj->needed, flags) == -1)
1734 load_preload_objects(void)
1736 char *p = ld_preload;
1737 static const char delim[] = " \t:;";
1742 p += strspn(p, delim);
1743 while (*p != '\0') {
1744 size_t len = strcspn(p, delim);
1749 if (load_object(p, -1, NULL, 0) == NULL)
1750 return -1; /* XXX - cleanup */
1753 p += strspn(p, delim);
1755 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
1760 printable_path(const char *path)
1763 return (path == NULL ? "<unknown>" : path);
1767 * Load a shared object into memory, if it is not already loaded. The
1768 * object may be specified by name or by user-supplied file descriptor
1769 * fd_u. In the later case, the fd_u descriptor is not closed, but its
1772 * Returns a pointer to the Obj_Entry for the object. Returns NULL
1776 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
1784 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
1785 if (object_match_name(obj, name))
1789 path = find_library(name, refobj);
1796 * If we didn't find a match by pathname, or the name is not
1797 * supplied, open the file and check again by device and inode.
1798 * This avoids false mismatches caused by multiple links or ".."
1801 * To avoid a race, we open the file and use fstat() rather than
1806 if ((fd = open(path, O_RDONLY)) == -1) {
1807 _rtld_error("Cannot open \"%s\"", path);
1814 _rtld_error("Cannot dup fd");
1819 if (fstat(fd, &sb) == -1) {
1820 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
1825 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1826 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
1828 if (obj != NULL && name != NULL) {
1829 object_add_name(obj, name);
1834 if (flags & RTLD_LO_NOLOAD) {
1840 /* First use of this object, so we must map it in */
1841 obj = do_load_object(fd, name, path, &sb, flags);
1850 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
1857 * but first, make sure that environment variables haven't been
1858 * used to circumvent the noexec flag on a filesystem.
1860 if (dangerous_ld_env) {
1861 if (fstatfs(fd, &fs) != 0) {
1862 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
1865 if (fs.f_flags & MNT_NOEXEC) {
1866 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
1870 dbg("loading \"%s\"", printable_path(path));
1871 obj = map_object(fd, printable_path(path), sbp);
1876 * If DT_SONAME is present in the object, digest_dynamic2 already
1877 * added it to the object names.
1880 object_add_name(obj, name);
1882 digest_dynamic(obj, 0);
1883 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
1885 dbg("refusing to load non-loadable \"%s\"", obj->path);
1886 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
1887 munmap(obj->mapbase, obj->mapsize);
1893 obj_tail = &obj->next;
1896 linkmap_add(obj); /* for GDB & dlinfo() */
1897 max_stack_flags |= obj->stack_flags;
1899 dbg(" %p .. %p: %s", obj->mapbase,
1900 obj->mapbase + obj->mapsize - 1, obj->path);
1902 dbg(" WARNING: %s has impure text", obj->path);
1903 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
1910 obj_from_addr(const void *addr)
1914 for (obj = obj_list; obj != NULL; obj = obj->next) {
1915 if (addr < (void *) obj->mapbase)
1917 if (addr < (void *) (obj->mapbase + obj->mapsize))
1926 Elf_Addr *preinit_addr;
1929 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
1930 if (preinit_addr == NULL)
1933 for (index = 0; index < obj_main->preinit_array_num; index++) {
1934 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
1935 dbg("calling preinit function for %s at %p", obj_main->path,
1936 (void *)preinit_addr[index]);
1937 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
1938 0, 0, obj_main->path);
1939 call_init_pointer(obj_main, preinit_addr[index]);
1945 * Call the finalization functions for each of the objects in "list"
1946 * belonging to the DAG of "root" and referenced once. If NULL "root"
1947 * is specified, every finalization function will be called regardless
1948 * of the reference count and the list elements won't be freed. All of
1949 * the objects are expected to have non-NULL fini functions.
1952 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
1956 Elf_Addr *fini_addr;
1959 assert(root == NULL || root->refcount == 1);
1962 * Preserve the current error message since a fini function might
1963 * call into the dynamic linker and overwrite it.
1965 saved_msg = errmsg_save();
1967 STAILQ_FOREACH(elm, list, link) {
1968 if (root != NULL && (elm->obj->refcount != 1 ||
1969 objlist_find(&root->dagmembers, elm->obj) == NULL))
1971 /* Remove object from fini list to prevent recursive invocation. */
1972 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
1974 * XXX: If a dlopen() call references an object while the
1975 * fini function is in progress, we might end up trying to
1976 * unload the referenced object in dlclose() or the object
1977 * won't be unloaded although its fini function has been
1980 lock_release(rtld_bind_lock, lockstate);
1983 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
1984 * When this happens, DT_FINI_ARRAY is processed first.
1986 fini_addr = (Elf_Addr *)elm->obj->fini_array;
1987 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
1988 for (index = elm->obj->fini_array_num - 1; index >= 0;
1990 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
1991 dbg("calling fini function for %s at %p",
1992 elm->obj->path, (void *)fini_addr[index]);
1993 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
1994 (void *)fini_addr[index], 0, 0, elm->obj->path);
1995 call_initfini_pointer(elm->obj, fini_addr[index]);
1999 if (elm->obj->fini != (Elf_Addr)NULL) {
2000 dbg("calling fini function for %s at %p", elm->obj->path,
2001 (void *)elm->obj->fini);
2002 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2003 0, 0, elm->obj->path);
2004 call_initfini_pointer(elm->obj, elm->obj->fini);
2006 wlock_acquire(rtld_bind_lock, lockstate);
2007 /* No need to free anything if process is going down. */
2011 * We must restart the list traversal after every fini call
2012 * because a dlclose() call from the fini function or from
2013 * another thread might have modified the reference counts.
2017 } while (elm != NULL);
2018 errmsg_restore(saved_msg);
2022 * Call the initialization functions for each of the objects in
2023 * "list". All of the objects are expected to have non-NULL init
2027 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2032 Elf_Addr *init_addr;
2036 * Clean init_scanned flag so that objects can be rechecked and
2037 * possibly initialized earlier if any of vectors called below
2038 * cause the change by using dlopen.
2040 for (obj = obj_list; obj != NULL; obj = obj->next)
2041 obj->init_scanned = false;
2044 * Preserve the current error message since an init function might
2045 * call into the dynamic linker and overwrite it.
2047 saved_msg = errmsg_save();
2048 STAILQ_FOREACH(elm, list, link) {
2049 if (elm->obj->init_done) /* Initialized early. */
2052 * Race: other thread might try to use this object before current
2053 * one completes the initilization. Not much can be done here
2054 * without better locking.
2056 elm->obj->init_done = true;
2057 lock_release(rtld_bind_lock, lockstate);
2060 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2061 * When this happens, DT_INIT is processed first.
2063 if (elm->obj->init != (Elf_Addr)NULL) {
2064 dbg("calling init function for %s at %p", elm->obj->path,
2065 (void *)elm->obj->init);
2066 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2067 0, 0, elm->obj->path);
2068 call_initfini_pointer(elm->obj, elm->obj->init);
2070 init_addr = (Elf_Addr *)elm->obj->init_array;
2071 if (init_addr != NULL) {
2072 for (index = 0; index < elm->obj->init_array_num; index++) {
2073 if (init_addr[index] != 0 && init_addr[index] != 1) {
2074 dbg("calling init function for %s at %p", elm->obj->path,
2075 (void *)init_addr[index]);
2076 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2077 (void *)init_addr[index], 0, 0, elm->obj->path);
2078 call_init_pointer(elm->obj, init_addr[index]);
2082 wlock_acquire(rtld_bind_lock, lockstate);
2084 errmsg_restore(saved_msg);
2088 objlist_clear(Objlist *list)
2092 while (!STAILQ_EMPTY(list)) {
2093 elm = STAILQ_FIRST(list);
2094 STAILQ_REMOVE_HEAD(list, link);
2099 static Objlist_Entry *
2100 objlist_find(Objlist *list, const Obj_Entry *obj)
2104 STAILQ_FOREACH(elm, list, link)
2105 if (elm->obj == obj)
2111 objlist_init(Objlist *list)
2117 objlist_push_head(Objlist *list, Obj_Entry *obj)
2121 elm = NEW(Objlist_Entry);
2123 STAILQ_INSERT_HEAD(list, elm, link);
2127 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2131 elm = NEW(Objlist_Entry);
2133 STAILQ_INSERT_TAIL(list, elm, link);
2137 objlist_remove(Objlist *list, Obj_Entry *obj)
2141 if ((elm = objlist_find(list, obj)) != NULL) {
2142 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2148 * Relocate newly-loaded shared objects. The argument is a pointer to
2149 * the Obj_Entry for the first such object. All objects from the first
2150 * to the end of the list of objects are relocated. Returns 0 on success,
2154 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2155 int flags, RtldLockState *lockstate)
2159 for (obj = first; obj != NULL; obj = obj->next) {
2162 obj->relocated = true;
2164 dbg("relocating \"%s\"", obj->path);
2166 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL ||
2167 obj->symtab == NULL || obj->strtab == NULL) {
2168 _rtld_error("%s: Shared object has no run-time symbol table",
2174 /* There are relocations to the write-protected text segment. */
2175 if (mprotect(obj->mapbase, obj->textsize,
2176 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2177 _rtld_error("%s: Cannot write-enable text segment: %s",
2178 obj->path, rtld_strerror(errno));
2183 /* Process the non-PLT relocations. */
2184 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2187 if (obj->textrel) { /* Re-protected the text segment. */
2188 if (mprotect(obj->mapbase, obj->textsize,
2189 PROT_READ|PROT_EXEC) == -1) {
2190 _rtld_error("%s: Cannot write-protect text segment: %s",
2191 obj->path, rtld_strerror(errno));
2197 /* Set the special PLT or GOT entries. */
2200 /* Process the PLT relocations. */
2201 if (reloc_plt(obj) == -1)
2203 /* Relocate the jump slots if we are doing immediate binding. */
2204 if (obj->bind_now || bind_now)
2205 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2208 if (obj->relro_size > 0) {
2209 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) {
2210 _rtld_error("%s: Cannot enforce relro protection: %s",
2211 obj->path, rtld_strerror(errno));
2217 * Set up the magic number and version in the Obj_Entry. These
2218 * were checked in the crt1.o from the original ElfKit, so we
2219 * set them for backward compatibility.
2221 obj->magic = RTLD_MAGIC;
2222 obj->version = RTLD_VERSION;
2229 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2230 * referencing STT_GNU_IFUNC symbols is postponed till the other
2231 * relocations are done. The indirect functions specified as
2232 * ifunc are allowed to call other symbols, so we need to have
2233 * objects relocated before asking for resolution from indirects.
2235 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2236 * instead of the usual lazy handling of PLT slots. It is
2237 * consistent with how GNU does it.
2240 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2241 RtldLockState *lockstate)
2243 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2245 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2246 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2252 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2253 RtldLockState *lockstate)
2257 for (obj = first; obj != NULL; obj = obj->next) {
2258 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2265 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2266 RtldLockState *lockstate)
2270 STAILQ_FOREACH(elm, list, link) {
2271 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2279 * Cleanup procedure. It will be called (by the atexit mechanism) just
2280 * before the process exits.
2285 RtldLockState lockstate;
2287 wlock_acquire(rtld_bind_lock, &lockstate);
2289 objlist_call_fini(&list_fini, NULL, &lockstate);
2290 /* No need to remove the items from the list, since we are exiting. */
2291 if (!libmap_disable)
2293 lock_release(rtld_bind_lock, &lockstate);
2297 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2305 path += strspn(path, ":;");
2306 while (*path != '\0') {
2310 len = strcspn(path, ":;");
2312 trans = lm_findn(NULL, path, len);
2314 res = callback(trans, strlen(trans), arg);
2317 res = callback(path, len, arg);
2323 path += strspn(path, ":;");
2329 struct try_library_args {
2337 try_library_path(const char *dir, size_t dirlen, void *param)
2339 struct try_library_args *arg;
2342 if (*dir == '/' || trust) {
2345 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2348 pathname = arg->buffer;
2349 strncpy(pathname, dir, dirlen);
2350 pathname[dirlen] = '/';
2351 strcpy(pathname + dirlen + 1, arg->name);
2353 dbg(" Trying \"%s\"", pathname);
2354 if (access(pathname, F_OK) == 0) { /* We found it */
2355 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2356 strcpy(pathname, arg->buffer);
2364 search_library_path(const char *name, const char *path)
2367 struct try_library_args arg;
2373 arg.namelen = strlen(name);
2374 arg.buffer = xmalloc(PATH_MAX);
2375 arg.buflen = PATH_MAX;
2377 p = path_enumerate(path, try_library_path, &arg);
2385 dlclose(void *handle)
2388 RtldLockState lockstate;
2390 wlock_acquire(rtld_bind_lock, &lockstate);
2391 root = dlcheck(handle);
2393 lock_release(rtld_bind_lock, &lockstate);
2396 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2399 /* Unreference the object and its dependencies. */
2400 root->dl_refcount--;
2402 if (root->refcount == 1) {
2404 * The object will be no longer referenced, so we must unload it.
2405 * First, call the fini functions.
2407 objlist_call_fini(&list_fini, root, &lockstate);
2411 /* Finish cleaning up the newly-unreferenced objects. */
2412 GDB_STATE(RT_DELETE,&root->linkmap);
2413 unload_object(root);
2414 GDB_STATE(RT_CONSISTENT,NULL);
2418 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2419 lock_release(rtld_bind_lock, &lockstate);
2426 char *msg = error_message;
2427 error_message = NULL;
2432 * This function is deprecated and has no effect.
2435 dllockinit(void *context,
2436 void *(*lock_create)(void *context),
2437 void (*rlock_acquire)(void *lock),
2438 void (*wlock_acquire)(void *lock),
2439 void (*lock_release)(void *lock),
2440 void (*lock_destroy)(void *lock),
2441 void (*context_destroy)(void *context))
2443 static void *cur_context;
2444 static void (*cur_context_destroy)(void *);
2446 /* Just destroy the context from the previous call, if necessary. */
2447 if (cur_context_destroy != NULL)
2448 cur_context_destroy(cur_context);
2449 cur_context = context;
2450 cur_context_destroy = context_destroy;
2454 dlopen(const char *name, int mode)
2457 return (rtld_dlopen(name, -1, mode));
2461 fdlopen(int fd, int mode)
2464 return (rtld_dlopen(NULL, fd, mode));
2468 rtld_dlopen(const char *name, int fd, int mode)
2470 RtldLockState lockstate;
2473 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2474 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2475 if (ld_tracing != NULL) {
2476 rlock_acquire(rtld_bind_lock, &lockstate);
2477 if (sigsetjmp(lockstate.env, 0) != 0)
2478 lock_upgrade(rtld_bind_lock, &lockstate);
2479 environ = (char **)*get_program_var_addr("environ", &lockstate);
2480 lock_release(rtld_bind_lock, &lockstate);
2482 lo_flags = RTLD_LO_DLOPEN;
2483 if (mode & RTLD_NODELETE)
2484 lo_flags |= RTLD_LO_NODELETE;
2485 if (mode & RTLD_NOLOAD)
2486 lo_flags |= RTLD_LO_NOLOAD;
2487 if (ld_tracing != NULL)
2488 lo_flags |= RTLD_LO_TRACE;
2490 return (dlopen_object(name, fd, obj_main, lo_flags,
2491 mode & (RTLD_MODEMASK | RTLD_GLOBAL)));
2495 dlopen_cleanup(Obj_Entry *obj)
2500 if (obj->refcount == 0)
2505 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2508 Obj_Entry **old_obj_tail;
2511 RtldLockState lockstate;
2514 objlist_init(&initlist);
2516 wlock_acquire(rtld_bind_lock, &lockstate);
2517 GDB_STATE(RT_ADD,NULL);
2519 old_obj_tail = obj_tail;
2521 if (name == NULL && fd == -1) {
2525 obj = load_object(name, fd, refobj, lo_flags);
2530 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2531 objlist_push_tail(&list_global, obj);
2532 if (*old_obj_tail != NULL) { /* We loaded something new. */
2533 assert(*old_obj_tail == obj);
2534 result = load_needed_objects(obj,
2535 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
2539 result = rtld_verify_versions(&obj->dagmembers);
2540 if (result != -1 && ld_tracing)
2542 if (result == -1 || (relocate_objects(obj,
2543 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
2544 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2545 &lockstate)) == -1) {
2546 dlopen_cleanup(obj);
2548 } else if (lo_flags & RTLD_LO_EARLY) {
2550 * Do not call the init functions for early loaded
2551 * filtees. The image is still not initialized enough
2554 * Our object is found by the global object list and
2555 * will be ordered among all init calls done right
2556 * before transferring control to main.
2559 /* Make list of init functions to call. */
2560 initlist_add_objects(obj, &obj->next, &initlist);
2565 * Bump the reference counts for objects on this DAG. If
2566 * this is the first dlopen() call for the object that was
2567 * already loaded as a dependency, initialize the dag
2573 if ((lo_flags & RTLD_LO_TRACE) != 0)
2576 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2577 obj->z_nodelete) && !obj->ref_nodel) {
2578 dbg("obj %s nodelete", obj->path);
2580 obj->z_nodelete = obj->ref_nodel = true;
2584 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2586 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2588 if (!(lo_flags & RTLD_LO_EARLY)) {
2589 map_stacks_exec(&lockstate);
2592 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
2593 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2594 &lockstate) == -1) {
2595 objlist_clear(&initlist);
2596 dlopen_cleanup(obj);
2597 lock_release(rtld_bind_lock, &lockstate);
2601 if (!(lo_flags & RTLD_LO_EARLY)) {
2602 /* Call the init functions. */
2603 objlist_call_init(&initlist, &lockstate);
2605 objlist_clear(&initlist);
2606 lock_release(rtld_bind_lock, &lockstate);
2609 trace_loaded_objects(obj);
2610 lock_release(rtld_bind_lock, &lockstate);
2615 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
2619 const Obj_Entry *obj, *defobj;
2622 RtldLockState lockstate;
2627 symlook_init(&req, name);
2629 req.flags = flags | SYMLOOK_IN_PLT;
2630 req.lockstate = &lockstate;
2632 rlock_acquire(rtld_bind_lock, &lockstate);
2633 if (sigsetjmp(lockstate.env, 0) != 0)
2634 lock_upgrade(rtld_bind_lock, &lockstate);
2635 if (handle == NULL || handle == RTLD_NEXT ||
2636 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
2638 if ((obj = obj_from_addr(retaddr)) == NULL) {
2639 _rtld_error("Cannot determine caller's shared object");
2640 lock_release(rtld_bind_lock, &lockstate);
2643 if (handle == NULL) { /* Just the caller's shared object. */
2644 res = symlook_obj(&req, obj);
2647 defobj = req.defobj_out;
2649 } else if (handle == RTLD_NEXT || /* Objects after caller's */
2650 handle == RTLD_SELF) { /* ... caller included */
2651 if (handle == RTLD_NEXT)
2653 for (; obj != NULL; obj = obj->next) {
2654 res = symlook_obj(&req, obj);
2657 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
2659 defobj = req.defobj_out;
2660 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
2666 * Search the dynamic linker itself, and possibly resolve the
2667 * symbol from there. This is how the application links to
2668 * dynamic linker services such as dlopen.
2670 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2671 res = symlook_obj(&req, &obj_rtld);
2674 defobj = req.defobj_out;
2678 assert(handle == RTLD_DEFAULT);
2679 res = symlook_default(&req, obj);
2681 defobj = req.defobj_out;
2686 if ((obj = dlcheck(handle)) == NULL) {
2687 lock_release(rtld_bind_lock, &lockstate);
2691 donelist_init(&donelist);
2692 if (obj->mainprog) {
2693 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
2694 res = symlook_global(&req, &donelist);
2697 defobj = req.defobj_out;
2700 * Search the dynamic linker itself, and possibly resolve the
2701 * symbol from there. This is how the application links to
2702 * dynamic linker services such as dlopen.
2704 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2705 res = symlook_obj(&req, &obj_rtld);
2708 defobj = req.defobj_out;
2713 /* Search the whole DAG rooted at the given object. */
2714 res = symlook_list(&req, &obj->dagmembers, &donelist);
2717 defobj = req.defobj_out;
2723 lock_release(rtld_bind_lock, &lockstate);
2726 * The value required by the caller is derived from the value
2727 * of the symbol. For the ia64 architecture, we need to
2728 * construct a function descriptor which the caller can use to
2729 * call the function with the right 'gp' value. For other
2730 * architectures and for non-functions, the value is simply
2731 * the relocated value of the symbol.
2733 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
2734 return (make_function_pointer(def, defobj));
2735 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
2736 return (rtld_resolve_ifunc(defobj, def));
2738 return (defobj->relocbase + def->st_value);
2741 _rtld_error("Undefined symbol \"%s\"", name);
2742 lock_release(rtld_bind_lock, &lockstate);
2747 dlsym(void *handle, const char *name)
2749 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
2754 dlfunc(void *handle, const char *name)
2761 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
2767 dlvsym(void *handle, const char *name, const char *version)
2771 ventry.name = version;
2773 ventry.hash = elf_hash(version);
2775 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
2780 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
2782 const Obj_Entry *obj;
2783 RtldLockState lockstate;
2785 rlock_acquire(rtld_bind_lock, &lockstate);
2786 obj = obj_from_addr(addr);
2788 _rtld_error("No shared object contains address");
2789 lock_release(rtld_bind_lock, &lockstate);
2792 rtld_fill_dl_phdr_info(obj, phdr_info);
2793 lock_release(rtld_bind_lock, &lockstate);
2798 dladdr(const void *addr, Dl_info *info)
2800 const Obj_Entry *obj;
2803 unsigned long symoffset;
2804 RtldLockState lockstate;
2806 rlock_acquire(rtld_bind_lock, &lockstate);
2807 obj = obj_from_addr(addr);
2809 _rtld_error("No shared object contains address");
2810 lock_release(rtld_bind_lock, &lockstate);
2813 info->dli_fname = obj->path;
2814 info->dli_fbase = obj->mapbase;
2815 info->dli_saddr = (void *)0;
2816 info->dli_sname = NULL;
2819 * Walk the symbol list looking for the symbol whose address is
2820 * closest to the address sent in.
2822 for (symoffset = 0; symoffset < obj->nchains; symoffset++) {
2823 def = obj->symtab + symoffset;
2826 * For skip the symbol if st_shndx is either SHN_UNDEF or
2829 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
2833 * If the symbol is greater than the specified address, or if it
2834 * is further away from addr than the current nearest symbol,
2837 symbol_addr = obj->relocbase + def->st_value;
2838 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
2841 /* Update our idea of the nearest symbol. */
2842 info->dli_sname = obj->strtab + def->st_name;
2843 info->dli_saddr = symbol_addr;
2846 if (info->dli_saddr == addr)
2849 lock_release(rtld_bind_lock, &lockstate);
2854 dlinfo(void *handle, int request, void *p)
2856 const Obj_Entry *obj;
2857 RtldLockState lockstate;
2860 rlock_acquire(rtld_bind_lock, &lockstate);
2862 if (handle == NULL || handle == RTLD_SELF) {
2865 retaddr = __builtin_return_address(0); /* __GNUC__ only */
2866 if ((obj = obj_from_addr(retaddr)) == NULL)
2867 _rtld_error("Cannot determine caller's shared object");
2869 obj = dlcheck(handle);
2872 lock_release(rtld_bind_lock, &lockstate);
2878 case RTLD_DI_LINKMAP:
2879 *((struct link_map const **)p) = &obj->linkmap;
2881 case RTLD_DI_ORIGIN:
2882 error = rtld_dirname(obj->path, p);
2885 case RTLD_DI_SERINFOSIZE:
2886 case RTLD_DI_SERINFO:
2887 error = do_search_info(obj, request, (struct dl_serinfo *)p);
2891 _rtld_error("Invalid request %d passed to dlinfo()", request);
2895 lock_release(rtld_bind_lock, &lockstate);
2901 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
2904 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
2905 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
2906 STAILQ_FIRST(&obj->names)->name : obj->path;
2907 phdr_info->dlpi_phdr = obj->phdr;
2908 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
2909 phdr_info->dlpi_tls_modid = obj->tlsindex;
2910 phdr_info->dlpi_tls_data = obj->tlsinit;
2911 phdr_info->dlpi_adds = obj_loads;
2912 phdr_info->dlpi_subs = obj_loads - obj_count;
2916 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
2918 struct dl_phdr_info phdr_info;
2919 const Obj_Entry *obj;
2920 RtldLockState bind_lockstate, phdr_lockstate;
2923 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
2924 rlock_acquire(rtld_bind_lock, &bind_lockstate);
2928 for (obj = obj_list; obj != NULL; obj = obj->next) {
2929 rtld_fill_dl_phdr_info(obj, &phdr_info);
2930 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
2934 lock_release(rtld_bind_lock, &bind_lockstate);
2935 lock_release(rtld_phdr_lock, &phdr_lockstate);
2940 struct fill_search_info_args {
2943 Dl_serinfo *serinfo;
2944 Dl_serpath *serpath;
2949 fill_search_info(const char *dir, size_t dirlen, void *param)
2951 struct fill_search_info_args *arg;
2955 if (arg->request == RTLD_DI_SERINFOSIZE) {
2956 arg->serinfo->dls_cnt ++;
2957 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1;
2959 struct dl_serpath *s_entry;
2961 s_entry = arg->serpath;
2962 s_entry->dls_name = arg->strspace;
2963 s_entry->dls_flags = arg->flags;
2965 strncpy(arg->strspace, dir, dirlen);
2966 arg->strspace[dirlen] = '\0';
2968 arg->strspace += dirlen + 1;
2976 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
2978 struct dl_serinfo _info;
2979 struct fill_search_info_args args;
2981 args.request = RTLD_DI_SERINFOSIZE;
2982 args.serinfo = &_info;
2984 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2987 path_enumerate(ld_library_path, fill_search_info, &args);
2988 path_enumerate(obj->rpath, fill_search_info, &args);
2989 path_enumerate(gethints(), fill_search_info, &args);
2990 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
2993 if (request == RTLD_DI_SERINFOSIZE) {
2994 info->dls_size = _info.dls_size;
2995 info->dls_cnt = _info.dls_cnt;
2999 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3000 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3004 args.request = RTLD_DI_SERINFO;
3005 args.serinfo = info;
3006 args.serpath = &info->dls_serpath[0];
3007 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3009 args.flags = LA_SER_LIBPATH;
3010 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3013 args.flags = LA_SER_RUNPATH;
3014 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3017 args.flags = LA_SER_CONFIG;
3018 if (path_enumerate(gethints(), fill_search_info, &args) != NULL)
3021 args.flags = LA_SER_DEFAULT;
3022 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3028 rtld_dirname(const char *path, char *bname)
3032 /* Empty or NULL string gets treated as "." */
3033 if (path == NULL || *path == '\0') {
3039 /* Strip trailing slashes */
3040 endp = path + strlen(path) - 1;
3041 while (endp > path && *endp == '/')
3044 /* Find the start of the dir */
3045 while (endp > path && *endp != '/')
3048 /* Either the dir is "/" or there are no slashes */
3050 bname[0] = *endp == '/' ? '/' : '.';
3056 } while (endp > path && *endp == '/');
3059 if (endp - path + 2 > PATH_MAX)
3061 _rtld_error("Filename is too long: %s", path);
3065 strncpy(bname, path, endp - path + 1);
3066 bname[endp - path + 1] = '\0';
3071 rtld_dirname_abs(const char *path, char *base)
3073 char base_rel[PATH_MAX];
3075 if (rtld_dirname(path, base) == -1)
3079 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
3080 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
3081 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
3083 strcpy(base, base_rel);
3088 linkmap_add(Obj_Entry *obj)
3090 struct link_map *l = &obj->linkmap;
3091 struct link_map *prev;
3093 obj->linkmap.l_name = obj->path;
3094 obj->linkmap.l_addr = obj->mapbase;
3095 obj->linkmap.l_ld = obj->dynamic;
3097 /* GDB needs load offset on MIPS to use the symbols */
3098 obj->linkmap.l_offs = obj->relocbase;
3101 if (r_debug.r_map == NULL) {
3107 * Scan to the end of the list, but not past the entry for the
3108 * dynamic linker, which we want to keep at the very end.
3110 for (prev = r_debug.r_map;
3111 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3112 prev = prev->l_next)
3115 /* Link in the new entry. */
3117 l->l_next = prev->l_next;
3118 if (l->l_next != NULL)
3119 l->l_next->l_prev = l;
3124 linkmap_delete(Obj_Entry *obj)
3126 struct link_map *l = &obj->linkmap;
3128 if (l->l_prev == NULL) {
3129 if ((r_debug.r_map = l->l_next) != NULL)
3130 l->l_next->l_prev = NULL;
3134 if ((l->l_prev->l_next = l->l_next) != NULL)
3135 l->l_next->l_prev = l->l_prev;
3139 * Function for the debugger to set a breakpoint on to gain control.
3141 * The two parameters allow the debugger to easily find and determine
3142 * what the runtime loader is doing and to whom it is doing it.
3144 * When the loadhook trap is hit (r_debug_state, set at program
3145 * initialization), the arguments can be found on the stack:
3147 * +8 struct link_map *m
3148 * +4 struct r_debug *rd
3152 r_debug_state(struct r_debug* rd, struct link_map *m)
3155 * The following is a hack to force the compiler to emit calls to
3156 * this function, even when optimizing. If the function is empty,
3157 * the compiler is not obliged to emit any code for calls to it,
3158 * even when marked __noinline. However, gdb depends on those
3161 __asm __volatile("" : : : "memory");
3165 * Get address of the pointer variable in the main program.
3166 * Prefer non-weak symbol over the weak one.
3168 static const void **
3169 get_program_var_addr(const char *name, RtldLockState *lockstate)
3174 symlook_init(&req, name);
3175 req.lockstate = lockstate;
3176 donelist_init(&donelist);
3177 if (symlook_global(&req, &donelist) != 0)
3179 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3180 return ((const void **)make_function_pointer(req.sym_out,
3182 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3183 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3185 return ((const void **)(req.defobj_out->relocbase +
3186 req.sym_out->st_value));
3190 * Set a pointer variable in the main program to the given value. This
3191 * is used to set key variables such as "environ" before any of the
3192 * init functions are called.
3195 set_program_var(const char *name, const void *value)
3199 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3200 dbg("\"%s\": *%p <-- %p", name, addr, value);
3206 * Search the global objects, including dependencies and main object,
3207 * for the given symbol.
3210 symlook_global(SymLook *req, DoneList *donelist)
3213 const Objlist_Entry *elm;
3216 symlook_init_from_req(&req1, req);
3218 /* Search all objects loaded at program start up. */
3219 if (req->defobj_out == NULL ||
3220 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3221 res = symlook_list(&req1, &list_main, donelist);
3222 if (res == 0 && (req->defobj_out == NULL ||
3223 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3224 req->sym_out = req1.sym_out;
3225 req->defobj_out = req1.defobj_out;
3226 assert(req->defobj_out != NULL);
3230 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3231 STAILQ_FOREACH(elm, &list_global, link) {
3232 if (req->defobj_out != NULL &&
3233 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3235 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3236 if (res == 0 && (req->defobj_out == NULL ||
3237 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3238 req->sym_out = req1.sym_out;
3239 req->defobj_out = req1.defobj_out;
3240 assert(req->defobj_out != NULL);
3244 return (req->sym_out != NULL ? 0 : ESRCH);
3248 * Given a symbol name in a referencing object, find the corresponding
3249 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3250 * no definition was found. Returns a pointer to the Obj_Entry of the
3251 * defining object via the reference parameter DEFOBJ_OUT.
3254 symlook_default(SymLook *req, const Obj_Entry *refobj)
3257 const Objlist_Entry *elm;
3261 donelist_init(&donelist);
3262 symlook_init_from_req(&req1, req);
3264 /* Look first in the referencing object if linked symbolically. */
3265 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3266 res = symlook_obj(&req1, refobj);
3268 req->sym_out = req1.sym_out;
3269 req->defobj_out = req1.defobj_out;
3270 assert(req->defobj_out != NULL);
3274 symlook_global(req, &donelist);
3276 /* Search all dlopened DAGs containing the referencing object. */
3277 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3278 if (req->sym_out != NULL &&
3279 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3281 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3282 if (res == 0 && (req->sym_out == NULL ||
3283 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3284 req->sym_out = req1.sym_out;
3285 req->defobj_out = req1.defobj_out;
3286 assert(req->defobj_out != NULL);
3291 * Search the dynamic linker itself, and possibly resolve the
3292 * symbol from there. This is how the application links to
3293 * dynamic linker services such as dlopen.
3295 if (req->sym_out == NULL ||
3296 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3297 res = symlook_obj(&req1, &obj_rtld);
3299 req->sym_out = req1.sym_out;
3300 req->defobj_out = req1.defobj_out;
3301 assert(req->defobj_out != NULL);
3305 return (req->sym_out != NULL ? 0 : ESRCH);
3309 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3312 const Obj_Entry *defobj;
3313 const Objlist_Entry *elm;
3319 STAILQ_FOREACH(elm, objlist, link) {
3320 if (donelist_check(dlp, elm->obj))
3322 symlook_init_from_req(&req1, req);
3323 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3324 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3326 defobj = req1.defobj_out;
3327 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3334 req->defobj_out = defobj;
3341 * Search the chain of DAGS cointed to by the given Needed_Entry
3342 * for a symbol of the given name. Each DAG is scanned completely
3343 * before advancing to the next one. Returns a pointer to the symbol,
3344 * or NULL if no definition was found.
3347 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3350 const Needed_Entry *n;
3351 const Obj_Entry *defobj;
3357 symlook_init_from_req(&req1, req);
3358 for (n = needed; n != NULL; n = n->next) {
3359 if (n->obj == NULL ||
3360 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3362 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3364 defobj = req1.defobj_out;
3365 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3371 req->defobj_out = defobj;
3378 * Search the symbol table of a single shared object for a symbol of
3379 * the given name and version, if requested. Returns a pointer to the
3380 * symbol, or NULL if no definition was found. If the object is
3381 * filter, return filtered symbol from filtee.
3383 * The symbol's hash value is passed in for efficiency reasons; that
3384 * eliminates many recomputations of the hash value.
3387 symlook_obj(SymLook *req, const Obj_Entry *obj)
3391 int flags, res, mres;
3393 mres = symlook_obj1(req, obj);
3395 if (obj->needed_filtees != NULL) {
3396 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3397 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3398 donelist_init(&donelist);
3399 symlook_init_from_req(&req1, req);
3400 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3402 req->sym_out = req1.sym_out;
3403 req->defobj_out = req1.defobj_out;
3407 if (obj->needed_aux_filtees != NULL) {
3408 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3409 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3410 donelist_init(&donelist);
3411 symlook_init_from_req(&req1, req);
3412 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3414 req->sym_out = req1.sym_out;
3415 req->defobj_out = req1.defobj_out;
3424 symlook_obj1(SymLook *req, const Obj_Entry *obj)
3426 unsigned long symnum;
3427 const Elf_Sym *vsymp;
3431 if (obj->buckets == NULL)
3436 symnum = obj->buckets[req->hash % obj->nbuckets];
3438 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
3439 const Elf_Sym *symp;
3442 if (symnum >= obj->nchains)
3443 return (ESRCH); /* Bad object */
3445 symp = obj->symtab + symnum;
3446 strp = obj->strtab + symp->st_name;
3448 switch (ELF_ST_TYPE(symp->st_info)) {
3453 if (symp->st_value == 0)
3457 if (symp->st_shndx != SHN_UNDEF)
3460 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3461 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3468 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3471 if (req->ventry == NULL) {
3472 if (obj->versyms != NULL) {
3473 verndx = VER_NDX(obj->versyms[symnum]);
3474 if (verndx > obj->vernum) {
3475 _rtld_error("%s: symbol %s references wrong version %d",
3476 obj->path, obj->strtab + symnum, verndx);
3480 * If we are not called from dlsym (i.e. this is a normal
3481 * relocation from unversioned binary), accept the symbol
3482 * immediately if it happens to have first version after
3483 * this shared object became versioned. Otherwise, if
3484 * symbol is versioned and not hidden, remember it. If it
3485 * is the only symbol with this name exported by the
3486 * shared object, it will be returned as a match at the
3487 * end of the function. If symbol is global (verndx < 2)
3488 * accept it unconditionally.
3490 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3491 verndx == VER_NDX_GIVEN) {
3492 req->sym_out = symp;
3493 req->defobj_out = obj;
3496 else if (verndx >= VER_NDX_GIVEN) {
3497 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) {
3505 req->sym_out = symp;
3506 req->defobj_out = obj;
3509 if (obj->versyms == NULL) {
3510 if (object_match_name(obj, req->ventry->name)) {
3511 _rtld_error("%s: object %s should provide version %s for "
3512 "symbol %s", obj_rtld.path, obj->path,
3513 req->ventry->name, obj->strtab + symnum);
3517 verndx = VER_NDX(obj->versyms[symnum]);
3518 if (verndx > obj->vernum) {
3519 _rtld_error("%s: symbol %s references wrong version %d",
3520 obj->path, obj->strtab + symnum, verndx);
3523 if (obj->vertab[verndx].hash != req->ventry->hash ||
3524 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3526 * Version does not match. Look if this is a global symbol
3527 * and if it is not hidden. If global symbol (verndx < 2)
3528 * is available, use it. Do not return symbol if we are
3529 * called by dlvsym, because dlvsym looks for a specific
3530 * version and default one is not what dlvsym wants.
3532 if ((req->flags & SYMLOOK_DLSYM) ||
3533 (obj->versyms[symnum] & VER_NDX_HIDDEN) ||
3534 (verndx >= VER_NDX_GIVEN))
3538 req->sym_out = symp;
3539 req->defobj_out = obj;
3544 req->sym_out = vsymp;
3545 req->defobj_out = obj;
3552 trace_loaded_objects(Obj_Entry *obj)
3554 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
3557 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
3560 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
3561 fmt1 = "\t%o => %p (%x)\n";
3563 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
3564 fmt2 = "\t%o (%x)\n";
3566 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
3568 for (; obj; obj = obj->next) {
3569 Needed_Entry *needed;
3573 if (list_containers && obj->needed != NULL)
3574 rtld_printf("%s:\n", obj->path);
3575 for (needed = obj->needed; needed; needed = needed->next) {
3576 if (needed->obj != NULL) {
3577 if (needed->obj->traced && !list_containers)
3579 needed->obj->traced = true;
3580 path = needed->obj->path;
3584 name = (char *)obj->strtab + needed->name;
3585 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
3587 fmt = is_lib ? fmt1 : fmt2;
3588 while ((c = *fmt++) != '\0') {
3614 rtld_putstr(main_local);
3617 rtld_putstr(obj_main->path);
3624 rtld_printf("%d", sodp->sod_major);
3627 rtld_printf("%d", sodp->sod_minor);
3634 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
3647 * Unload a dlopened object and its dependencies from memory and from
3648 * our data structures. It is assumed that the DAG rooted in the
3649 * object has already been unreferenced, and that the object has a
3650 * reference count of 0.
3653 unload_object(Obj_Entry *root)
3658 assert(root->refcount == 0);
3661 * Pass over the DAG removing unreferenced objects from
3662 * appropriate lists.
3664 unlink_object(root);
3666 /* Unmap all objects that are no longer referenced. */
3667 linkp = &obj_list->next;
3668 while ((obj = *linkp) != NULL) {
3669 if (obj->refcount == 0) {
3670 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
3672 dbg("unloading \"%s\"", obj->path);
3673 unload_filtees(root);
3674 munmap(obj->mapbase, obj->mapsize);
3675 linkmap_delete(obj);
3686 unlink_object(Obj_Entry *root)
3690 if (root->refcount == 0) {
3691 /* Remove the object from the RTLD_GLOBAL list. */
3692 objlist_remove(&list_global, root);
3694 /* Remove the object from all objects' DAG lists. */
3695 STAILQ_FOREACH(elm, &root->dagmembers, link) {
3696 objlist_remove(&elm->obj->dldags, root);
3697 if (elm->obj != root)
3698 unlink_object(elm->obj);
3704 ref_dag(Obj_Entry *root)
3708 assert(root->dag_inited);
3709 STAILQ_FOREACH(elm, &root->dagmembers, link)
3710 elm->obj->refcount++;
3714 unref_dag(Obj_Entry *root)
3718 assert(root->dag_inited);
3719 STAILQ_FOREACH(elm, &root->dagmembers, link)
3720 elm->obj->refcount--;
3724 * Common code for MD __tls_get_addr().
3726 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
3728 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
3730 Elf_Addr *newdtv, *dtv;
3731 RtldLockState lockstate;
3735 /* Check dtv generation in case new modules have arrived */
3736 if (dtv[0] != tls_dtv_generation) {
3737 wlock_acquire(rtld_bind_lock, &lockstate);
3738 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
3740 if (to_copy > tls_max_index)
3741 to_copy = tls_max_index;
3742 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
3743 newdtv[0] = tls_dtv_generation;
3744 newdtv[1] = tls_max_index;
3746 lock_release(rtld_bind_lock, &lockstate);
3747 dtv = *dtvp = newdtv;
3750 /* Dynamically allocate module TLS if necessary */
3751 if (dtv[index + 1] == 0) {
3752 /* Signal safe, wlock will block out signals. */
3753 wlock_acquire(rtld_bind_lock, &lockstate);
3754 if (!dtv[index + 1])
3755 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
3756 lock_release(rtld_bind_lock, &lockstate);
3758 return ((void *)(dtv[index + 1] + offset));
3762 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
3767 /* Check dtv generation in case new modules have arrived */
3768 if (__predict_true(dtv[0] == tls_dtv_generation &&
3769 dtv[index + 1] != 0))
3770 return ((void *)(dtv[index + 1] + offset));
3771 return (tls_get_addr_slow(dtvp, index, offset));
3774 /* XXX not sure what variants to use for arm. */
3776 #if defined(__ia64__) || defined(__powerpc__)
3779 * Allocate Static TLS using the Variant I method.
3782 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
3791 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
3794 assert(tcbsize >= TLS_TCB_SIZE);
3795 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
3796 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
3798 if (oldtcb != NULL) {
3799 memcpy(tls, oldtcb, tls_static_space);
3802 /* Adjust the DTV. */
3804 for (i = 0; i < dtv[1]; i++) {
3805 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
3806 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
3807 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
3811 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr));
3813 dtv[0] = tls_dtv_generation;
3814 dtv[1] = tls_max_index;
3816 for (obj = objs; obj; obj = obj->next) {
3817 if (obj->tlsoffset > 0) {
3818 addr = (Elf_Addr)tls + obj->tlsoffset;
3819 if (obj->tlsinitsize > 0)
3820 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
3821 if (obj->tlssize > obj->tlsinitsize)
3822 memset((void*) (addr + obj->tlsinitsize), 0,
3823 obj->tlssize - obj->tlsinitsize);
3824 dtv[obj->tlsindex + 1] = addr;
3833 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
3836 Elf_Addr tlsstart, tlsend;
3839 assert(tcbsize >= TLS_TCB_SIZE);
3841 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
3842 tlsend = tlsstart + tls_static_space;
3844 dtv = *(Elf_Addr **)tlsstart;
3846 for (i = 0; i < dtvsize; i++) {
3847 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
3848 free((void*)dtv[i+2]);
3857 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \
3858 defined(__arm__) || defined(__mips__)
3861 * Allocate Static TLS using the Variant II method.
3864 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
3869 Elf_Addr *dtv, *olddtv;
3870 Elf_Addr segbase, oldsegbase, addr;
3873 size = round(tls_static_space, tcbalign);
3875 assert(tcbsize >= 2*sizeof(Elf_Addr));
3876 tls = calloc(1, size + tcbsize);
3877 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
3879 segbase = (Elf_Addr)(tls + size);
3880 ((Elf_Addr*)segbase)[0] = segbase;
3881 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
3883 dtv[0] = tls_dtv_generation;
3884 dtv[1] = tls_max_index;
3888 * Copy the static TLS block over whole.
3890 oldsegbase = (Elf_Addr) oldtls;
3891 memcpy((void *)(segbase - tls_static_space),
3892 (const void *)(oldsegbase - tls_static_space),
3896 * If any dynamic TLS blocks have been created tls_get_addr(),
3899 olddtv = ((Elf_Addr**)oldsegbase)[1];
3900 for (i = 0; i < olddtv[1]; i++) {
3901 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
3902 dtv[i+2] = olddtv[i+2];
3908 * We assume that this block was the one we created with
3909 * allocate_initial_tls().
3911 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
3913 for (obj = objs; obj; obj = obj->next) {
3914 if (obj->tlsoffset) {
3915 addr = segbase - obj->tlsoffset;
3916 memset((void*) (addr + obj->tlsinitsize),
3917 0, obj->tlssize - obj->tlsinitsize);
3919 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
3920 dtv[obj->tlsindex + 1] = addr;
3925 return (void*) segbase;
3929 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
3934 Elf_Addr tlsstart, tlsend;
3937 * Figure out the size of the initial TLS block so that we can
3938 * find stuff which ___tls_get_addr() allocated dynamically.
3940 size = round(tls_static_space, tcbalign);
3942 dtv = ((Elf_Addr**)tls)[1];
3944 tlsend = (Elf_Addr) tls;
3945 tlsstart = tlsend - size;
3946 for (i = 0; i < dtvsize; i++) {
3947 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) {
3948 free((void*) dtv[i+2]);
3952 free((void*) tlsstart);
3959 * Allocate TLS block for module with given index.
3962 allocate_module_tls(int index)
3967 for (obj = obj_list; obj; obj = obj->next) {
3968 if (obj->tlsindex == index)
3972 _rtld_error("Can't find module with TLS index %d", index);
3976 p = malloc(obj->tlssize);
3978 _rtld_error("Cannot allocate TLS block for index %d", index);
3981 memcpy(p, obj->tlsinit, obj->tlsinitsize);
3982 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
3988 allocate_tls_offset(Obj_Entry *obj)
3995 if (obj->tlssize == 0) {
3996 obj->tls_done = true;
4000 if (obj->tlsindex == 1)
4001 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4003 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4004 obj->tlssize, obj->tlsalign);
4007 * If we have already fixed the size of the static TLS block, we
4008 * must stay within that size. When allocating the static TLS, we
4009 * leave a small amount of space spare to be used for dynamically
4010 * loading modules which use static TLS.
4012 if (tls_static_space) {
4013 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4017 tls_last_offset = obj->tlsoffset = off;
4018 tls_last_size = obj->tlssize;
4019 obj->tls_done = true;
4025 free_tls_offset(Obj_Entry *obj)
4029 * If we were the last thing to allocate out of the static TLS
4030 * block, we give our space back to the 'allocator'. This is a
4031 * simplistic workaround to allow libGL.so.1 to be loaded and
4032 * unloaded multiple times.
4034 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4035 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4036 tls_last_offset -= obj->tlssize;
4042 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4045 RtldLockState lockstate;
4047 wlock_acquire(rtld_bind_lock, &lockstate);
4048 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4049 lock_release(rtld_bind_lock, &lockstate);
4054 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4056 RtldLockState lockstate;
4058 wlock_acquire(rtld_bind_lock, &lockstate);
4059 free_tls(tcb, tcbsize, tcbalign);
4060 lock_release(rtld_bind_lock, &lockstate);
4064 object_add_name(Obj_Entry *obj, const char *name)
4070 entry = malloc(sizeof(Name_Entry) + len);
4072 if (entry != NULL) {
4073 strcpy(entry->name, name);
4074 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4079 object_match_name(const Obj_Entry *obj, const char *name)
4083 STAILQ_FOREACH(entry, &obj->names, link) {
4084 if (strcmp(name, entry->name) == 0)
4091 locate_dependency(const Obj_Entry *obj, const char *name)
4093 const Objlist_Entry *entry;
4094 const Needed_Entry *needed;
4096 STAILQ_FOREACH(entry, &list_main, link) {
4097 if (object_match_name(entry->obj, name))
4101 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4102 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4103 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4105 * If there is DT_NEEDED for the name we are looking for,
4106 * we are all set. Note that object might not be found if
4107 * dependency was not loaded yet, so the function can
4108 * return NULL here. This is expected and handled
4109 * properly by the caller.
4111 return (needed->obj);
4114 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4120 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4121 const Elf_Vernaux *vna)
4123 const Elf_Verdef *vd;
4124 const char *vername;
4126 vername = refobj->strtab + vna->vna_name;
4127 vd = depobj->verdef;
4129 _rtld_error("%s: version %s required by %s not defined",
4130 depobj->path, vername, refobj->path);
4134 if (vd->vd_version != VER_DEF_CURRENT) {
4135 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4136 depobj->path, vd->vd_version);
4139 if (vna->vna_hash == vd->vd_hash) {
4140 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4141 ((char *)vd + vd->vd_aux);
4142 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4145 if (vd->vd_next == 0)
4147 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4149 if (vna->vna_flags & VER_FLG_WEAK)
4151 _rtld_error("%s: version %s required by %s not found",
4152 depobj->path, vername, refobj->path);
4157 rtld_verify_object_versions(Obj_Entry *obj)
4159 const Elf_Verneed *vn;
4160 const Elf_Verdef *vd;
4161 const Elf_Verdaux *vda;
4162 const Elf_Vernaux *vna;
4163 const Obj_Entry *depobj;
4164 int maxvernum, vernum;
4166 if (obj->ver_checked)
4168 obj->ver_checked = true;
4172 * Walk over defined and required version records and figure out
4173 * max index used by any of them. Do very basic sanity checking
4177 while (vn != NULL) {
4178 if (vn->vn_version != VER_NEED_CURRENT) {
4179 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4180 obj->path, vn->vn_version);
4183 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4185 vernum = VER_NEED_IDX(vna->vna_other);
4186 if (vernum > maxvernum)
4188 if (vna->vna_next == 0)
4190 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4192 if (vn->vn_next == 0)
4194 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4198 while (vd != NULL) {
4199 if (vd->vd_version != VER_DEF_CURRENT) {
4200 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4201 obj->path, vd->vd_version);
4204 vernum = VER_DEF_IDX(vd->vd_ndx);
4205 if (vernum > maxvernum)
4207 if (vd->vd_next == 0)
4209 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4216 * Store version information in array indexable by version index.
4217 * Verify that object version requirements are satisfied along the
4220 obj->vernum = maxvernum + 1;
4221 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry));
4224 while (vd != NULL) {
4225 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4226 vernum = VER_DEF_IDX(vd->vd_ndx);
4227 assert(vernum <= maxvernum);
4228 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4229 obj->vertab[vernum].hash = vd->vd_hash;
4230 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4231 obj->vertab[vernum].file = NULL;
4232 obj->vertab[vernum].flags = 0;
4234 if (vd->vd_next == 0)
4236 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4240 while (vn != NULL) {
4241 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4244 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4246 if (check_object_provided_version(obj, depobj, vna))
4248 vernum = VER_NEED_IDX(vna->vna_other);
4249 assert(vernum <= maxvernum);
4250 obj->vertab[vernum].hash = vna->vna_hash;
4251 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4252 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4253 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4254 VER_INFO_HIDDEN : 0;
4255 if (vna->vna_next == 0)
4257 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4259 if (vn->vn_next == 0)
4261 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4267 rtld_verify_versions(const Objlist *objlist)
4269 Objlist_Entry *entry;
4273 STAILQ_FOREACH(entry, objlist, link) {
4275 * Skip dummy objects or objects that have their version requirements
4278 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4280 if (rtld_verify_object_versions(entry->obj) == -1) {
4282 if (ld_tracing == NULL)
4286 if (rc == 0 || ld_tracing != NULL)
4287 rc = rtld_verify_object_versions(&obj_rtld);
4292 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4297 vernum = VER_NDX(obj->versyms[symnum]);
4298 if (vernum >= obj->vernum) {
4299 _rtld_error("%s: symbol %s has wrong verneed value %d",
4300 obj->path, obj->strtab + symnum, vernum);
4301 } else if (obj->vertab[vernum].hash != 0) {
4302 return &obj->vertab[vernum];
4309 _rtld_get_stack_prot(void)
4312 return (stack_prot);
4316 map_stacks_exec(RtldLockState *lockstate)
4318 void (*thr_map_stacks_exec)(void);
4320 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4322 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4323 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4324 if (thr_map_stacks_exec != NULL) {
4325 stack_prot |= PROT_EXEC;
4326 thr_map_stacks_exec();
4331 symlook_init(SymLook *dst, const char *name)
4334 bzero(dst, sizeof(*dst));
4336 dst->hash = elf_hash(name);
4340 symlook_init_from_req(SymLook *dst, const SymLook *src)
4343 dst->name = src->name;
4344 dst->hash = src->hash;
4345 dst->ventry = src->ventry;
4346 dst->flags = src->flags;
4347 dst->defobj_out = NULL;
4348 dst->sym_out = NULL;
4349 dst->lockstate = src->lockstate;
4353 * Overrides for libc_pic-provided functions.
4357 __getosreldate(void)
4367 oid[1] = KERN_OSRELDATE;
4369 len = sizeof(osrel);
4370 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4371 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4377 * No unresolved symbols for rtld.
4380 __pthread_cxa_finalize(struct dl_phdr_info *a)
4385 __stack_chk_fail(void)
4388 _rtld_error("stack overflow detected; terminated");
4396 _rtld_error("buffer overflow detected; terminated");
4401 rtld_strerror(int errnum)
4404 if (errnum < 0 || errnum >= sys_nerr)
4405 return ("Unknown error");
4406 return (sys_errlist[errnum]);