2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * Copyright 2009-2012 Konstantin Belousov <kib@FreeBSD.ORG>.
5 * Copyright 2012 John Marino <draco@marino.st>.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 * Dynamic linker for ELF.
34 * John Polstra <jdp@polstra.com>.
38 #error "GCC is needed to compile this file"
41 #include <sys/param.h>
42 #include <sys/mount.h>
45 #include <sys/sysctl.h>
47 #include <sys/utsname.h>
48 #include <sys/ktrace.h>
64 #include "rtld_printf.h"
68 #define PATH_RTLD "/libexec/ld-elf.so.1"
70 #define PATH_RTLD "/libexec/ld-elf32.so.1"
74 typedef void (*func_ptr_type)();
75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
78 * Function declarations.
80 static const char *basename(const char *);
81 static void die(void) __dead2;
82 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
83 const Elf_Dyn **, const Elf_Dyn **);
84 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
86 static void digest_dynamic(Obj_Entry *, int);
87 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
88 static Obj_Entry *dlcheck(void *);
89 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
90 int lo_flags, int mode, RtldLockState *lockstate);
91 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
92 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
93 static bool donelist_check(DoneList *, const Obj_Entry *);
94 static void errmsg_restore(char *);
95 static char *errmsg_save(void);
96 static void *fill_search_info(const char *, size_t, void *);
97 static char *find_library(const char *, const Obj_Entry *);
98 static const char *gethints(bool);
99 static void init_dag(Obj_Entry *);
100 static void init_rtld(caddr_t, Elf_Auxinfo **);
101 static void initlist_add_neededs(Needed_Entry *, Objlist *);
102 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
103 static void linkmap_add(Obj_Entry *);
104 static void linkmap_delete(Obj_Entry *);
105 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
106 static void unload_filtees(Obj_Entry *);
107 static int load_needed_objects(Obj_Entry *, int);
108 static int load_preload_objects(void);
109 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
110 static void map_stacks_exec(RtldLockState *);
111 static Obj_Entry *obj_from_addr(const void *);
112 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
113 static void objlist_call_init(Objlist *, RtldLockState *);
114 static void objlist_clear(Objlist *);
115 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
116 static void objlist_init(Objlist *);
117 static void objlist_push_head(Objlist *, Obj_Entry *);
118 static void objlist_push_tail(Objlist *, Obj_Entry *);
119 static void objlist_remove(Objlist *, Obj_Entry *);
120 static void *path_enumerate(const char *, path_enum_proc, void *);
121 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
122 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
123 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
124 int flags, RtldLockState *lockstate);
125 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
127 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
128 int flags, RtldLockState *lockstate);
129 static int rtld_dirname(const char *, char *);
130 static int rtld_dirname_abs(const char *, char *);
131 static void *rtld_dlopen(const char *name, int fd, int mode);
132 static void rtld_exit(void);
133 static char *search_library_path(const char *, const char *);
134 static const void **get_program_var_addr(const char *, RtldLockState *);
135 static void set_program_var(const char *, const void *);
136 static int symlook_default(SymLook *, const Obj_Entry *refobj);
137 static int symlook_global(SymLook *, DoneList *);
138 static void symlook_init_from_req(SymLook *, const SymLook *);
139 static int symlook_list(SymLook *, const Objlist *, DoneList *);
140 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
141 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
142 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
143 static void trace_loaded_objects(Obj_Entry *);
144 static void unlink_object(Obj_Entry *);
145 static void unload_object(Obj_Entry *);
146 static void unref_dag(Obj_Entry *);
147 static void ref_dag(Obj_Entry *);
148 static char *origin_subst_one(char *, const char *, const char *, bool);
149 static char *origin_subst(char *, const char *);
150 static void preinit_main(void);
151 static int rtld_verify_versions(const Objlist *);
152 static int rtld_verify_object_versions(Obj_Entry *);
153 static void object_add_name(Obj_Entry *, const char *);
154 static int object_match_name(const Obj_Entry *, const char *);
155 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
156 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
157 struct dl_phdr_info *phdr_info);
158 static uint32_t gnu_hash(const char *);
159 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
160 const unsigned long);
162 void r_debug_state(struct r_debug *, struct link_map *) __noinline;
167 static char *error_message; /* Message for dlerror(), or NULL */
168 struct r_debug r_debug; /* for GDB; */
169 static bool libmap_disable; /* Disable libmap */
170 static bool ld_loadfltr; /* Immediate filters processing */
171 static char *libmap_override; /* Maps to use in addition to libmap.conf */
172 static bool trust; /* False for setuid and setgid programs */
173 static bool dangerous_ld_env; /* True if environment variables have been
174 used to affect the libraries loaded */
175 static char *ld_bind_now; /* Environment variable for immediate binding */
176 static char *ld_debug; /* Environment variable for debugging */
177 static char *ld_library_path; /* Environment variable for search path */
178 static char *ld_preload; /* Environment variable for libraries to
180 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
181 static char *ld_tracing; /* Called from ldd to print libs */
182 static char *ld_utrace; /* Use utrace() to log events. */
183 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
184 static Obj_Entry **obj_tail; /* Link field of last object in list */
185 static Obj_Entry *obj_main; /* The main program shared object */
186 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
187 static unsigned int obj_count; /* Number of objects in obj_list */
188 static unsigned int obj_loads; /* Number of objects in obj_list */
190 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
191 STAILQ_HEAD_INITIALIZER(list_global);
192 static Objlist list_main = /* Objects loaded at program startup */
193 STAILQ_HEAD_INITIALIZER(list_main);
194 static Objlist list_fini = /* Objects needing fini() calls */
195 STAILQ_HEAD_INITIALIZER(list_fini);
197 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
199 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
201 extern Elf_Dyn _DYNAMIC;
202 #pragma weak _DYNAMIC
203 #ifndef RTLD_IS_DYNAMIC
204 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
207 int osreldate, pagesize;
209 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
211 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
212 static int max_stack_flags;
215 * Global declarations normally provided by crt1. The dynamic linker is
216 * not built with crt1, so we have to provide them ourselves.
222 * Used to pass argc, argv to init functions.
228 * Globals to control TLS allocation.
230 size_t tls_last_offset; /* Static TLS offset of last module */
231 size_t tls_last_size; /* Static TLS size of last module */
232 size_t tls_static_space; /* Static TLS space allocated */
233 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
234 int tls_max_index = 1; /* Largest module index allocated */
236 bool ld_library_path_rpath = true;
239 * Fill in a DoneList with an allocation large enough to hold all of
240 * the currently-loaded objects. Keep this as a macro since it calls
241 * alloca and we want that to occur within the scope of the caller.
243 #define donelist_init(dlp) \
244 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
245 assert((dlp)->objs != NULL), \
246 (dlp)->num_alloc = obj_count, \
249 #define UTRACE_DLOPEN_START 1
250 #define UTRACE_DLOPEN_STOP 2
251 #define UTRACE_DLCLOSE_START 3
252 #define UTRACE_DLCLOSE_STOP 4
253 #define UTRACE_LOAD_OBJECT 5
254 #define UTRACE_UNLOAD_OBJECT 6
255 #define UTRACE_ADD_RUNDEP 7
256 #define UTRACE_PRELOAD_FINISHED 8
257 #define UTRACE_INIT_CALL 9
258 #define UTRACE_FINI_CALL 10
261 char sig[4]; /* 'RTLD' */
264 void *mapbase; /* Used for 'parent' and 'init/fini' */
266 int refcnt; /* Used for 'mode' */
267 char name[MAXPATHLEN];
270 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
271 if (ld_utrace != NULL) \
272 ld_utrace_log(e, h, mb, ms, r, n); \
276 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
277 int refcnt, const char *name)
279 struct utrace_rtld ut;
287 ut.mapbase = mapbase;
288 ut.mapsize = mapsize;
290 bzero(ut.name, sizeof(ut.name));
292 strlcpy(ut.name, name, sizeof(ut.name));
293 utrace(&ut, sizeof(ut));
297 * Main entry point for dynamic linking. The first argument is the
298 * stack pointer. The stack is expected to be laid out as described
299 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
300 * Specifically, the stack pointer points to a word containing
301 * ARGC. Following that in the stack is a null-terminated sequence
302 * of pointers to argument strings. Then comes a null-terminated
303 * sequence of pointers to environment strings. Finally, there is a
304 * sequence of "auxiliary vector" entries.
306 * The second argument points to a place to store the dynamic linker's
307 * exit procedure pointer and the third to a place to store the main
310 * The return value is the main program's entry point.
313 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
315 Elf_Auxinfo *aux_info[AT_COUNT];
323 Objlist_Entry *entry;
325 Obj_Entry **preload_tail;
327 RtldLockState lockstate;
328 char *library_path_rpath;
333 * On entry, the dynamic linker itself has not been relocated yet.
334 * Be very careful not to reference any global data until after
335 * init_rtld has returned. It is OK to reference file-scope statics
336 * and string constants, and to call static and global functions.
339 /* Find the auxiliary vector on the stack. */
342 sp += argc + 1; /* Skip over arguments and NULL terminator */
344 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
346 aux = (Elf_Auxinfo *) sp;
348 /* Digest the auxiliary vector. */
349 for (i = 0; i < AT_COUNT; i++)
351 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
352 if (auxp->a_type < AT_COUNT)
353 aux_info[auxp->a_type] = auxp;
356 /* Initialize and relocate ourselves. */
357 assert(aux_info[AT_BASE] != NULL);
358 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
360 __progname = obj_rtld.path;
361 argv0 = argv[0] != NULL ? argv[0] : "(null)";
366 if (aux_info[AT_CANARY] != NULL &&
367 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
368 i = aux_info[AT_CANARYLEN]->a_un.a_val;
369 if (i > sizeof(__stack_chk_guard))
370 i = sizeof(__stack_chk_guard);
371 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
376 len = sizeof(__stack_chk_guard);
377 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
378 len != sizeof(__stack_chk_guard)) {
379 /* If sysctl was unsuccessful, use the "terminator canary". */
380 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
381 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
382 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
383 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
387 trust = !issetugid();
389 ld_bind_now = getenv(LD_ "BIND_NOW");
391 * If the process is tainted, then we un-set the dangerous environment
392 * variables. The process will be marked as tainted until setuid(2)
393 * is called. If any child process calls setuid(2) we do not want any
394 * future processes to honor the potentially un-safe variables.
397 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
398 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") ||
399 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
400 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) {
401 _rtld_error("environment corrupt; aborting");
405 ld_debug = getenv(LD_ "DEBUG");
406 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
407 libmap_override = getenv(LD_ "LIBMAP");
408 ld_library_path = getenv(LD_ "LIBRARY_PATH");
409 ld_preload = getenv(LD_ "PRELOAD");
410 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
411 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
412 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH");
413 if (library_path_rpath != NULL) {
414 if (library_path_rpath[0] == 'y' ||
415 library_path_rpath[0] == 'Y' ||
416 library_path_rpath[0] == '1')
417 ld_library_path_rpath = true;
419 ld_library_path_rpath = false;
421 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
422 (ld_library_path != NULL) || (ld_preload != NULL) ||
423 (ld_elf_hints_path != NULL) || ld_loadfltr;
424 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
425 ld_utrace = getenv(LD_ "UTRACE");
427 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
428 ld_elf_hints_path = _PATH_ELF_HINTS;
430 if (ld_debug != NULL && *ld_debug != '\0')
432 dbg("%s is initialized, base address = %p", __progname,
433 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
434 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
435 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
437 dbg("initializing thread locks");
441 * Load the main program, or process its program header if it is
444 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
445 int fd = aux_info[AT_EXECFD]->a_un.a_val;
446 dbg("loading main program");
447 obj_main = map_object(fd, argv0, NULL);
449 if (obj_main == NULL)
451 max_stack_flags = obj->stack_flags;
452 } else { /* Main program already loaded. */
453 const Elf_Phdr *phdr;
457 dbg("processing main program's program header");
458 assert(aux_info[AT_PHDR] != NULL);
459 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
460 assert(aux_info[AT_PHNUM] != NULL);
461 phnum = aux_info[AT_PHNUM]->a_un.a_val;
462 assert(aux_info[AT_PHENT] != NULL);
463 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
464 assert(aux_info[AT_ENTRY] != NULL);
465 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
466 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
470 if (aux_info[AT_EXECPATH] != 0) {
472 char buf[MAXPATHLEN];
474 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
475 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
476 if (kexecpath[0] == '/')
477 obj_main->path = kexecpath;
478 else if (getcwd(buf, sizeof(buf)) == NULL ||
479 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
480 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
481 obj_main->path = xstrdup(argv0);
483 obj_main->path = xstrdup(buf);
485 dbg("No AT_EXECPATH");
486 obj_main->path = xstrdup(argv0);
488 dbg("obj_main path %s", obj_main->path);
489 obj_main->mainprog = true;
491 if (aux_info[AT_STACKPROT] != NULL &&
492 aux_info[AT_STACKPROT]->a_un.a_val != 0)
493 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
496 * Get the actual dynamic linker pathname from the executable if
497 * possible. (It should always be possible.) That ensures that
498 * gdb will find the right dynamic linker even if a non-standard
501 if (obj_main->interp != NULL &&
502 strcmp(obj_main->interp, obj_rtld.path) != 0) {
504 obj_rtld.path = xstrdup(obj_main->interp);
505 __progname = obj_rtld.path;
508 digest_dynamic(obj_main, 0);
509 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
510 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
511 obj_main->dynsymcount);
513 linkmap_add(obj_main);
514 linkmap_add(&obj_rtld);
516 /* Link the main program into the list of objects. */
517 *obj_tail = obj_main;
518 obj_tail = &obj_main->next;
522 /* Initialize a fake symbol for resolving undefined weak references. */
523 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
524 sym_zero.st_shndx = SHN_UNDEF;
525 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
528 libmap_disable = (bool)lm_init(libmap_override);
530 dbg("loading LD_PRELOAD libraries");
531 if (load_preload_objects() == -1)
533 preload_tail = obj_tail;
535 dbg("loading needed objects");
536 if (load_needed_objects(obj_main, 0) == -1)
539 /* Make a list of all objects loaded at startup. */
540 for (obj = obj_list; obj != NULL; obj = obj->next) {
541 objlist_push_tail(&list_main, obj);
545 dbg("checking for required versions");
546 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
549 if (ld_tracing) { /* We're done */
550 trace_loaded_objects(obj_main);
554 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
555 dump_relocations(obj_main);
560 * Processing tls relocations requires having the tls offsets
561 * initialized. Prepare offsets before starting initial
562 * relocation processing.
564 dbg("initializing initial thread local storage offsets");
565 STAILQ_FOREACH(entry, &list_main, link) {
567 * Allocate all the initial objects out of the static TLS
568 * block even if they didn't ask for it.
570 allocate_tls_offset(entry->obj);
573 if (relocate_objects(obj_main,
574 ld_bind_now != NULL && *ld_bind_now != '\0',
575 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
578 dbg("doing copy relocations");
579 if (do_copy_relocations(obj_main) == -1)
582 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
583 dump_relocations(obj_main);
588 * Setup TLS for main thread. This must be done after the
589 * relocations are processed, since tls initialization section
590 * might be the subject for relocations.
592 dbg("initializing initial thread local storage");
593 allocate_initial_tls(obj_list);
595 dbg("initializing key program variables");
596 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
597 set_program_var("environ", env);
598 set_program_var("__elf_aux_vector", aux);
600 /* Make a list of init functions to call. */
601 objlist_init(&initlist);
602 initlist_add_objects(obj_list, preload_tail, &initlist);
604 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
606 map_stacks_exec(NULL);
608 dbg("resolving ifuncs");
609 if (resolve_objects_ifunc(obj_main,
610 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
614 if (!obj_main->crt_no_init) {
616 * Make sure we don't call the main program's init and fini
617 * functions for binaries linked with old crt1 which calls
620 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
621 obj_main->preinit_array = obj_main->init_array =
622 obj_main->fini_array = (Elf_Addr)NULL;
625 wlock_acquire(rtld_bind_lock, &lockstate);
626 if (obj_main->crt_no_init)
628 objlist_call_init(&initlist, &lockstate);
629 objlist_clear(&initlist);
630 dbg("loading filtees");
631 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
632 if (ld_loadfltr || obj->z_loadfltr)
633 load_filtees(obj, 0, &lockstate);
635 lock_release(rtld_bind_lock, &lockstate);
637 dbg("transferring control to program entry point = %p", obj_main->entry);
639 /* Return the exit procedure and the program entry point. */
640 *exit_proc = rtld_exit;
642 return (func_ptr_type) obj_main->entry;
646 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
651 ptr = (void *)make_function_pointer(def, obj);
652 target = ((Elf_Addr (*)(void))ptr)();
653 return ((void *)target);
657 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
661 const Obj_Entry *defobj;
664 RtldLockState lockstate;
666 rlock_acquire(rtld_bind_lock, &lockstate);
667 if (sigsetjmp(lockstate.env, 0) != 0)
668 lock_upgrade(rtld_bind_lock, &lockstate);
670 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
672 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
674 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
675 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
679 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
680 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
682 target = (Elf_Addr)(defobj->relocbase + def->st_value);
684 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
685 defobj->strtab + def->st_name, basename(obj->path),
686 (void *)target, basename(defobj->path));
689 * Write the new contents for the jmpslot. Note that depending on
690 * architecture, the value which we need to return back to the
691 * lazy binding trampoline may or may not be the target
692 * address. The value returned from reloc_jmpslot() is the value
693 * that the trampoline needs.
695 target = reloc_jmpslot(where, target, defobj, obj, rel);
696 lock_release(rtld_bind_lock, &lockstate);
701 * Error reporting function. Use it like printf. If formats the message
702 * into a buffer, and sets things up so that the next call to dlerror()
703 * will return the message.
706 _rtld_error(const char *fmt, ...)
708 static char buf[512];
712 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
718 * Return a dynamically-allocated copy of the current error message, if any.
723 return error_message == NULL ? NULL : xstrdup(error_message);
727 * Restore the current error message from a copy which was previously saved
728 * by errmsg_save(). The copy is freed.
731 errmsg_restore(char *saved_msg)
733 if (saved_msg == NULL)
734 error_message = NULL;
736 _rtld_error("%s", saved_msg);
742 basename(const char *name)
744 const char *p = strrchr(name, '/');
745 return p != NULL ? p + 1 : name;
748 static struct utsname uts;
751 origin_subst_one(char *real, const char *kw, const char *subst,
754 char *p, *p1, *res, *resp;
755 int subst_len, kw_len, subst_count, old_len, new_len;
760 * First, count the number of the keyword occurences, to
761 * preallocate the final string.
763 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
770 * If the keyword is not found, just return.
772 if (subst_count == 0)
773 return (may_free ? real : xstrdup(real));
776 * There is indeed something to substitute. Calculate the
777 * length of the resulting string, and allocate it.
779 subst_len = strlen(subst);
780 old_len = strlen(real);
781 new_len = old_len + (subst_len - kw_len) * subst_count;
782 res = xmalloc(new_len + 1);
785 * Now, execute the substitution loop.
787 for (p = real, resp = res, *resp = '\0';;) {
790 /* Copy the prefix before keyword. */
791 memcpy(resp, p, p1 - p);
793 /* Keyword replacement. */
794 memcpy(resp, subst, subst_len);
802 /* Copy to the end of string and finish. */
810 origin_subst(char *real, const char *origin_path)
812 char *res1, *res2, *res3, *res4;
814 if (uts.sysname[0] == '\0') {
815 if (uname(&uts) != 0) {
816 _rtld_error("utsname failed: %d", errno);
820 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false);
821 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true);
822 res3 = origin_subst_one(res2, "$OSREL", uts.release, true);
823 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true);
830 const char *msg = dlerror();
834 rtld_fdputstr(STDERR_FILENO, msg);
835 rtld_fdputchar(STDERR_FILENO, '\n');
840 * Process a shared object's DYNAMIC section, and save the important
841 * information in its Obj_Entry structure.
844 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
845 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
848 Needed_Entry **needed_tail = &obj->needed;
849 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
850 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
851 const Elf_Hashelt *hashtab;
852 const Elf32_Word *hashval;
853 Elf32_Word bkt, nmaskwords;
856 int plttype = DT_REL;
862 obj->bind_now = false;
863 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
864 switch (dynp->d_tag) {
867 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
871 obj->relsize = dynp->d_un.d_val;
875 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
879 obj->pltrel = (const Elf_Rel *)
880 (obj->relocbase + dynp->d_un.d_ptr);
884 obj->pltrelsize = dynp->d_un.d_val;
888 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
892 obj->relasize = dynp->d_un.d_val;
896 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
900 plttype = dynp->d_un.d_val;
901 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
905 obj->symtab = (const Elf_Sym *)
906 (obj->relocbase + dynp->d_un.d_ptr);
910 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
914 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
918 obj->strsize = dynp->d_un.d_val;
922 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
927 obj->verneednum = dynp->d_un.d_val;
931 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
936 obj->verdefnum = dynp->d_un.d_val;
940 obj->versyms = (const Elf_Versym *)(obj->relocbase +
946 hashtab = (const Elf_Hashelt *)(obj->relocbase +
948 obj->nbuckets = hashtab[0];
949 obj->nchains = hashtab[1];
950 obj->buckets = hashtab + 2;
951 obj->chains = obj->buckets + obj->nbuckets;
952 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
953 obj->buckets != NULL;
959 hashtab = (const Elf_Hashelt *)(obj->relocbase +
961 obj->nbuckets_gnu = hashtab[0];
962 obj->symndx_gnu = hashtab[1];
963 nmaskwords = hashtab[2];
964 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
965 /* Number of bitmask words is required to be power of 2 */
966 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0);
967 obj->maskwords_bm_gnu = nmaskwords - 1;
968 obj->shift2_gnu = hashtab[3];
969 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
970 obj->buckets_gnu = hashtab + 4 + bloom_size32;
971 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
973 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 &&
974 obj->buckets_gnu != NULL;
980 Needed_Entry *nep = NEW(Needed_Entry);
981 nep->name = dynp->d_un.d_val;
986 needed_tail = &nep->next;
992 Needed_Entry *nep = NEW(Needed_Entry);
993 nep->name = dynp->d_un.d_val;
997 *needed_filtees_tail = nep;
998 needed_filtees_tail = &nep->next;
1004 Needed_Entry *nep = NEW(Needed_Entry);
1005 nep->name = dynp->d_un.d_val;
1009 *needed_aux_filtees_tail = nep;
1010 needed_aux_filtees_tail = &nep->next;
1015 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1019 obj->textrel = true;
1023 obj->symbolic = true;
1028 * We have to wait until later to process this, because we
1029 * might not have gotten the address of the string table yet.
1039 *dyn_runpath = dynp;
1043 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1046 case DT_PREINIT_ARRAY:
1047 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1050 case DT_PREINIT_ARRAYSZ:
1051 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1055 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1058 case DT_INIT_ARRAYSZ:
1059 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1063 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1067 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1070 case DT_FINI_ARRAYSZ:
1071 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1075 * Don't process DT_DEBUG on MIPS as the dynamic section
1076 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1081 /* XXX - not implemented yet */
1083 dbg("Filling in DT_DEBUG entry");
1084 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1089 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1090 obj->z_origin = true;
1091 if (dynp->d_un.d_val & DF_SYMBOLIC)
1092 obj->symbolic = true;
1093 if (dynp->d_un.d_val & DF_TEXTREL)
1094 obj->textrel = true;
1095 if (dynp->d_un.d_val & DF_BIND_NOW)
1096 obj->bind_now = true;
1097 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1101 case DT_MIPS_LOCAL_GOTNO:
1102 obj->local_gotno = dynp->d_un.d_val;
1105 case DT_MIPS_SYMTABNO:
1106 obj->symtabno = dynp->d_un.d_val;
1109 case DT_MIPS_GOTSYM:
1110 obj->gotsym = dynp->d_un.d_val;
1113 case DT_MIPS_RLD_MAP:
1116 dbg("Filling in DT_DEBUG entry");
1117 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1123 if (dynp->d_un.d_val & DF_1_NOOPEN)
1124 obj->z_noopen = true;
1125 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1126 obj->z_origin = true;
1127 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1129 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1130 obj->bind_now = true;
1131 if (dynp->d_un.d_val & DF_1_NODELETE)
1132 obj->z_nodelete = true;
1133 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1134 obj->z_loadfltr = true;
1135 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1136 obj->z_nodeflib = true;
1141 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1148 obj->traced = false;
1150 if (plttype == DT_RELA) {
1151 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1153 obj->pltrelasize = obj->pltrelsize;
1154 obj->pltrelsize = 0;
1157 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1158 if (obj->valid_hash_sysv)
1159 obj->dynsymcount = obj->nchains;
1160 else if (obj->valid_hash_gnu) {
1161 obj->dynsymcount = 0;
1162 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1163 if (obj->buckets_gnu[bkt] == 0)
1165 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1168 while ((*hashval++ & 1u) == 0);
1170 obj->dynsymcount += obj->symndx_gnu;
1175 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1176 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1179 if (obj->z_origin && obj->origin_path == NULL) {
1180 obj->origin_path = xmalloc(PATH_MAX);
1181 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1185 if (dyn_runpath != NULL) {
1186 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1188 obj->runpath = origin_subst(obj->runpath, obj->origin_path);
1190 else if (dyn_rpath != NULL) {
1191 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1193 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1196 if (dyn_soname != NULL)
1197 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1201 digest_dynamic(Obj_Entry *obj, int early)
1203 const Elf_Dyn *dyn_rpath;
1204 const Elf_Dyn *dyn_soname;
1205 const Elf_Dyn *dyn_runpath;
1207 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1208 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1212 * Process a shared object's program header. This is used only for the
1213 * main program, when the kernel has already loaded the main program
1214 * into memory before calling the dynamic linker. It creates and
1215 * returns an Obj_Entry structure.
1218 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1221 const Elf_Phdr *phlimit = phdr + phnum;
1223 Elf_Addr note_start, note_end;
1227 for (ph = phdr; ph < phlimit; ph++) {
1228 if (ph->p_type != PT_PHDR)
1232 obj->phsize = ph->p_memsz;
1233 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1237 obj->stack_flags = PF_X | PF_R | PF_W;
1239 for (ph = phdr; ph < phlimit; ph++) {
1240 switch (ph->p_type) {
1243 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1247 if (nsegs == 0) { /* First load segment */
1248 obj->vaddrbase = trunc_page(ph->p_vaddr);
1249 obj->mapbase = obj->vaddrbase + obj->relocbase;
1250 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1252 } else { /* Last load segment */
1253 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1260 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1265 obj->tlssize = ph->p_memsz;
1266 obj->tlsalign = ph->p_align;
1267 obj->tlsinitsize = ph->p_filesz;
1268 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1272 obj->stack_flags = ph->p_flags;
1276 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1277 obj->relro_size = round_page(ph->p_memsz);
1281 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1282 note_end = note_start + ph->p_filesz;
1283 digest_notes(obj, note_start, note_end);
1288 _rtld_error("%s: too few PT_LOAD segments", path);
1297 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1299 const Elf_Note *note;
1300 const char *note_name;
1303 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1304 note = (const Elf_Note *)((const char *)(note + 1) +
1305 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1306 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1307 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1308 note->n_descsz != sizeof(int32_t))
1310 if (note->n_type != ABI_NOTETYPE &&
1311 note->n_type != CRT_NOINIT_NOTETYPE)
1313 note_name = (const char *)(note + 1);
1314 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1315 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1317 switch (note->n_type) {
1319 /* FreeBSD osrel note */
1320 p = (uintptr_t)(note + 1);
1321 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1322 obj->osrel = *(const int32_t *)(p);
1323 dbg("note osrel %d", obj->osrel);
1325 case CRT_NOINIT_NOTETYPE:
1326 /* FreeBSD 'crt does not call init' note */
1327 obj->crt_no_init = true;
1328 dbg("note crt_no_init");
1335 dlcheck(void *handle)
1339 for (obj = obj_list; obj != NULL; obj = obj->next)
1340 if (obj == (Obj_Entry *) handle)
1343 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1344 _rtld_error("Invalid shared object handle %p", handle);
1351 * If the given object is already in the donelist, return true. Otherwise
1352 * add the object to the list and return false.
1355 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1359 for (i = 0; i < dlp->num_used; i++)
1360 if (dlp->objs[i] == obj)
1363 * Our donelist allocation should always be sufficient. But if
1364 * our threads locking isn't working properly, more shared objects
1365 * could have been loaded since we allocated the list. That should
1366 * never happen, but we'll handle it properly just in case it does.
1368 if (dlp->num_used < dlp->num_alloc)
1369 dlp->objs[dlp->num_used++] = obj;
1374 * Hash function for symbol table lookup. Don't even think about changing
1375 * this. It is specified by the System V ABI.
1378 elf_hash(const char *name)
1380 const unsigned char *p = (const unsigned char *) name;
1381 unsigned long h = 0;
1384 while (*p != '\0') {
1385 h = (h << 4) + *p++;
1386 if ((g = h & 0xf0000000) != 0)
1394 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1395 * unsigned in case it's implemented with a wider type.
1398 gnu_hash(const char *s)
1404 for (c = *s; c != '\0'; c = *++s)
1406 return (h & 0xffffffff);
1410 * Find the library with the given name, and return its full pathname.
1411 * The returned string is dynamically allocated. Generates an error
1412 * message and returns NULL if the library cannot be found.
1414 * If the second argument is non-NULL, then it refers to an already-
1415 * loaded shared object, whose library search path will be searched.
1417 * The search order is:
1418 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1419 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1421 * DT_RUNPATH in the referencing file
1422 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1424 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1426 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1429 find_library(const char *xname, const Obj_Entry *refobj)
1433 bool nodeflib, objgiven;
1435 objgiven = refobj != NULL;
1436 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1437 if (xname[0] != '/' && !trust) {
1438 _rtld_error("Absolute pathname required for shared object \"%s\"",
1442 if (objgiven && refobj->z_origin) {
1443 return (origin_subst(__DECONST(char *, xname),
1444 refobj->origin_path));
1446 return (xstrdup(xname));
1450 if (libmap_disable || !objgiven ||
1451 (name = lm_find(refobj->path, xname)) == NULL)
1452 name = (char *)xname;
1454 dbg(" Searching for \"%s\"", name);
1457 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1458 * back to pre-conforming behaviour if user requested so with
1459 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1462 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1463 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1465 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1466 (pathname = search_library_path(name, gethints(false))) != NULL ||
1467 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1470 nodeflib = objgiven ? refobj->z_nodeflib : false;
1472 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1473 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1474 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1475 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1477 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1478 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1479 (objgiven && !nodeflib &&
1480 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1484 if (objgiven && refobj->path != NULL) {
1485 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1486 name, basename(refobj->path));
1488 _rtld_error("Shared object \"%s\" not found", name);
1494 * Given a symbol number in a referencing object, find the corresponding
1495 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1496 * no definition was found. Returns a pointer to the Obj_Entry of the
1497 * defining object via the reference parameter DEFOBJ_OUT.
1500 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1501 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1502 RtldLockState *lockstate)
1506 const Obj_Entry *defobj;
1512 * If we have already found this symbol, get the information from
1515 if (symnum >= refobj->dynsymcount)
1516 return NULL; /* Bad object */
1517 if (cache != NULL && cache[symnum].sym != NULL) {
1518 *defobj_out = cache[symnum].obj;
1519 return cache[symnum].sym;
1522 ref = refobj->symtab + symnum;
1523 name = refobj->strtab + ref->st_name;
1528 * We don't have to do a full scale lookup if the symbol is local.
1529 * We know it will bind to the instance in this load module; to
1530 * which we already have a pointer (ie ref). By not doing a lookup,
1531 * we not only improve performance, but it also avoids unresolvable
1532 * symbols when local symbols are not in the hash table. This has
1533 * been seen with the ia64 toolchain.
1535 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1536 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1537 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1540 symlook_init(&req, name);
1542 req.ventry = fetch_ventry(refobj, symnum);
1543 req.lockstate = lockstate;
1544 res = symlook_default(&req, refobj);
1547 defobj = req.defobj_out;
1555 * If we found no definition and the reference is weak, treat the
1556 * symbol as having the value zero.
1558 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1564 *defobj_out = defobj;
1565 /* Record the information in the cache to avoid subsequent lookups. */
1566 if (cache != NULL) {
1567 cache[symnum].sym = def;
1568 cache[symnum].obj = defobj;
1571 if (refobj != &obj_rtld)
1572 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1578 * Return the search path from the ldconfig hints file, reading it if
1579 * necessary. If nostdlib is true, then the default search paths are
1580 * not added to result.
1582 * Returns NULL if there are problems with the hints file,
1583 * or if the search path there is empty.
1586 gethints(bool nostdlib)
1588 static char *hints, *filtered_path;
1589 struct elfhints_hdr hdr;
1590 struct fill_search_info_args sargs, hargs;
1591 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1592 struct dl_serpath *SLPpath, *hintpath;
1594 unsigned int SLPndx, hintndx, fndx, fcount;
1599 /* First call, read the hints file */
1600 if (hints == NULL) {
1601 /* Keep from trying again in case the hints file is bad. */
1604 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1)
1606 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1607 hdr.magic != ELFHINTS_MAGIC ||
1612 p = xmalloc(hdr.dirlistlen + 1);
1613 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1614 read(fd, p, hdr.dirlistlen + 1) !=
1615 (ssize_t)hdr.dirlistlen + 1) {
1625 * If caller agreed to receive list which includes the default
1626 * paths, we are done. Otherwise, if we still did not
1627 * calculated filtered result, do it now.
1630 return (hints[0] != '\0' ? hints : NULL);
1631 if (filtered_path != NULL)
1635 * Obtain the list of all configured search paths, and the
1636 * list of the default paths.
1638 * First estimate the size of the results.
1640 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1642 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1645 sargs.request = RTLD_DI_SERINFOSIZE;
1646 sargs.serinfo = &smeta;
1647 hargs.request = RTLD_DI_SERINFOSIZE;
1648 hargs.serinfo = &hmeta;
1650 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1651 path_enumerate(p, fill_search_info, &hargs);
1653 SLPinfo = xmalloc(smeta.dls_size);
1654 hintinfo = xmalloc(hmeta.dls_size);
1657 * Next fetch both sets of paths.
1659 sargs.request = RTLD_DI_SERINFO;
1660 sargs.serinfo = SLPinfo;
1661 sargs.serpath = &SLPinfo->dls_serpath[0];
1662 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1664 hargs.request = RTLD_DI_SERINFO;
1665 hargs.serinfo = hintinfo;
1666 hargs.serpath = &hintinfo->dls_serpath[0];
1667 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1669 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1670 path_enumerate(p, fill_search_info, &hargs);
1673 * Now calculate the difference between two sets, by excluding
1674 * standard paths from the full set.
1678 filtered_path = xmalloc(hdr.dirlistlen + 1);
1679 hintpath = &hintinfo->dls_serpath[0];
1680 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1682 SLPpath = &SLPinfo->dls_serpath[0];
1684 * Check each standard path against current.
1686 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1687 /* matched, skip the path */
1688 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1696 * Not matched against any standard path, add the path
1697 * to result. Separate consequtive paths with ':'.
1700 filtered_path[fndx] = ':';
1704 flen = strlen(hintpath->dls_name);
1705 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1708 filtered_path[fndx] = '\0';
1714 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1718 init_dag(Obj_Entry *root)
1720 const Needed_Entry *needed;
1721 const Objlist_Entry *elm;
1724 if (root->dag_inited)
1726 donelist_init(&donelist);
1728 /* Root object belongs to own DAG. */
1729 objlist_push_tail(&root->dldags, root);
1730 objlist_push_tail(&root->dagmembers, root);
1731 donelist_check(&donelist, root);
1734 * Add dependencies of root object to DAG in breadth order
1735 * by exploiting the fact that each new object get added
1736 * to the tail of the dagmembers list.
1738 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1739 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1740 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1742 objlist_push_tail(&needed->obj->dldags, root);
1743 objlist_push_tail(&root->dagmembers, needed->obj);
1746 root->dag_inited = true;
1750 process_nodelete(Obj_Entry *root)
1752 const Objlist_Entry *elm;
1755 * Walk over object DAG and process every dependent object that
1756 * is marked as DF_1_NODELETE. They need to grow their own DAG,
1757 * which then should have its reference upped separately.
1759 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1760 if (elm->obj != NULL && elm->obj->z_nodelete &&
1761 !elm->obj->ref_nodel) {
1762 dbg("obj %s nodelete", elm->obj->path);
1765 elm->obj->ref_nodel = true;
1770 * Initialize the dynamic linker. The argument is the address at which
1771 * the dynamic linker has been mapped into memory. The primary task of
1772 * this function is to relocate the dynamic linker.
1775 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1777 Obj_Entry objtmp; /* Temporary rtld object */
1778 const Elf_Dyn *dyn_rpath;
1779 const Elf_Dyn *dyn_soname;
1780 const Elf_Dyn *dyn_runpath;
1783 * Conjure up an Obj_Entry structure for the dynamic linker.
1785 * The "path" member can't be initialized yet because string constants
1786 * cannot yet be accessed. Below we will set it correctly.
1788 memset(&objtmp, 0, sizeof(objtmp));
1791 objtmp.mapbase = mapbase;
1793 objtmp.relocbase = mapbase;
1795 if (RTLD_IS_DYNAMIC()) {
1796 objtmp.dynamic = rtld_dynamic(&objtmp);
1797 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1798 assert(objtmp.needed == NULL);
1799 #if !defined(__mips__)
1800 /* MIPS has a bogus DT_TEXTREL. */
1801 assert(!objtmp.textrel);
1805 * Temporarily put the dynamic linker entry into the object list, so
1806 * that symbols can be found.
1809 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1812 /* Initialize the object list. */
1813 obj_tail = &obj_list;
1815 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1816 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1818 if (aux_info[AT_PAGESZ] != NULL)
1819 pagesize = aux_info[AT_PAGESZ]->a_un.a_val;
1820 if (aux_info[AT_OSRELDATE] != NULL)
1821 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1823 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1825 /* Replace the path with a dynamically allocated copy. */
1826 obj_rtld.path = xstrdup(PATH_RTLD);
1828 r_debug.r_brk = r_debug_state;
1829 r_debug.r_state = RT_CONSISTENT;
1833 * Add the init functions from a needed object list (and its recursive
1834 * needed objects) to "list". This is not used directly; it is a helper
1835 * function for initlist_add_objects(). The write lock must be held
1836 * when this function is called.
1839 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1841 /* Recursively process the successor needed objects. */
1842 if (needed->next != NULL)
1843 initlist_add_neededs(needed->next, list);
1845 /* Process the current needed object. */
1846 if (needed->obj != NULL)
1847 initlist_add_objects(needed->obj, &needed->obj->next, list);
1851 * Scan all of the DAGs rooted in the range of objects from "obj" to
1852 * "tail" and add their init functions to "list". This recurses over
1853 * the DAGs and ensure the proper init ordering such that each object's
1854 * needed libraries are initialized before the object itself. At the
1855 * same time, this function adds the objects to the global finalization
1856 * list "list_fini" in the opposite order. The write lock must be
1857 * held when this function is called.
1860 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1863 if (obj->init_scanned || obj->init_done)
1865 obj->init_scanned = true;
1867 /* Recursively process the successor objects. */
1868 if (&obj->next != tail)
1869 initlist_add_objects(obj->next, tail, list);
1871 /* Recursively process the needed objects. */
1872 if (obj->needed != NULL)
1873 initlist_add_neededs(obj->needed, list);
1874 if (obj->needed_filtees != NULL)
1875 initlist_add_neededs(obj->needed_filtees, list);
1876 if (obj->needed_aux_filtees != NULL)
1877 initlist_add_neededs(obj->needed_aux_filtees, list);
1879 /* Add the object to the init list. */
1880 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1881 obj->init_array != (Elf_Addr)NULL)
1882 objlist_push_tail(list, obj);
1884 /* Add the object to the global fini list in the reverse order. */
1885 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1886 && !obj->on_fini_list) {
1887 objlist_push_head(&list_fini, obj);
1888 obj->on_fini_list = true;
1893 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1897 free_needed_filtees(Needed_Entry *n)
1899 Needed_Entry *needed, *needed1;
1901 for (needed = n; needed != NULL; needed = needed->next) {
1902 if (needed->obj != NULL) {
1903 dlclose(needed->obj);
1907 for (needed = n; needed != NULL; needed = needed1) {
1908 needed1 = needed->next;
1914 unload_filtees(Obj_Entry *obj)
1917 free_needed_filtees(obj->needed_filtees);
1918 obj->needed_filtees = NULL;
1919 free_needed_filtees(obj->needed_aux_filtees);
1920 obj->needed_aux_filtees = NULL;
1921 obj->filtees_loaded = false;
1925 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
1926 RtldLockState *lockstate)
1929 for (; needed != NULL; needed = needed->next) {
1930 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
1931 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
1932 RTLD_LOCAL, lockstate);
1937 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
1940 lock_restart_for_upgrade(lockstate);
1941 if (!obj->filtees_loaded) {
1942 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
1943 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
1944 obj->filtees_loaded = true;
1949 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
1953 for (; needed != NULL; needed = needed->next) {
1954 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
1955 flags & ~RTLD_LO_NOLOAD);
1956 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
1963 * Given a shared object, traverse its list of needed objects, and load
1964 * each of them. Returns 0 on success. Generates an error message and
1965 * returns -1 on failure.
1968 load_needed_objects(Obj_Entry *first, int flags)
1972 for (obj = first; obj != NULL; obj = obj->next) {
1973 if (process_needed(obj, obj->needed, flags) == -1)
1980 load_preload_objects(void)
1982 char *p = ld_preload;
1983 static const char delim[] = " \t:;";
1988 p += strspn(p, delim);
1989 while (*p != '\0') {
1990 size_t len = strcspn(p, delim);
1995 if (load_object(p, -1, NULL, 0) == NULL)
1996 return -1; /* XXX - cleanup */
1999 p += strspn(p, delim);
2001 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2006 printable_path(const char *path)
2009 return (path == NULL ? "<unknown>" : path);
2013 * Load a shared object into memory, if it is not already loaded. The
2014 * object may be specified by name or by user-supplied file descriptor
2015 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2018 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2022 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2030 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2031 if (object_match_name(obj, name))
2035 path = find_library(name, refobj);
2042 * If we didn't find a match by pathname, or the name is not
2043 * supplied, open the file and check again by device and inode.
2044 * This avoids false mismatches caused by multiple links or ".."
2047 * To avoid a race, we open the file and use fstat() rather than
2052 if ((fd = open(path, O_RDONLY)) == -1) {
2053 _rtld_error("Cannot open \"%s\"", path);
2060 _rtld_error("Cannot dup fd");
2065 if (fstat(fd, &sb) == -1) {
2066 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2071 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2072 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2074 if (obj != NULL && name != NULL) {
2075 object_add_name(obj, name);
2080 if (flags & RTLD_LO_NOLOAD) {
2086 /* First use of this object, so we must map it in */
2087 obj = do_load_object(fd, name, path, &sb, flags);
2096 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2103 * but first, make sure that environment variables haven't been
2104 * used to circumvent the noexec flag on a filesystem.
2106 if (dangerous_ld_env) {
2107 if (fstatfs(fd, &fs) != 0) {
2108 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2111 if (fs.f_flags & MNT_NOEXEC) {
2112 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2116 dbg("loading \"%s\"", printable_path(path));
2117 obj = map_object(fd, printable_path(path), sbp);
2122 * If DT_SONAME is present in the object, digest_dynamic2 already
2123 * added it to the object names.
2126 object_add_name(obj, name);
2128 digest_dynamic(obj, 0);
2129 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2130 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2131 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2133 dbg("refusing to load non-loadable \"%s\"", obj->path);
2134 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2135 munmap(obj->mapbase, obj->mapsize);
2141 obj_tail = &obj->next;
2144 linkmap_add(obj); /* for GDB & dlinfo() */
2145 max_stack_flags |= obj->stack_flags;
2147 dbg(" %p .. %p: %s", obj->mapbase,
2148 obj->mapbase + obj->mapsize - 1, obj->path);
2150 dbg(" WARNING: %s has impure text", obj->path);
2151 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2158 obj_from_addr(const void *addr)
2162 for (obj = obj_list; obj != NULL; obj = obj->next) {
2163 if (addr < (void *) obj->mapbase)
2165 if (addr < (void *) (obj->mapbase + obj->mapsize))
2174 Elf_Addr *preinit_addr;
2177 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2178 if (preinit_addr == NULL)
2181 for (index = 0; index < obj_main->preinit_array_num; index++) {
2182 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2183 dbg("calling preinit function for %s at %p", obj_main->path,
2184 (void *)preinit_addr[index]);
2185 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2186 0, 0, obj_main->path);
2187 call_init_pointer(obj_main, preinit_addr[index]);
2193 * Call the finalization functions for each of the objects in "list"
2194 * belonging to the DAG of "root" and referenced once. If NULL "root"
2195 * is specified, every finalization function will be called regardless
2196 * of the reference count and the list elements won't be freed. All of
2197 * the objects are expected to have non-NULL fini functions.
2200 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2204 Elf_Addr *fini_addr;
2207 assert(root == NULL || root->refcount == 1);
2210 * Preserve the current error message since a fini function might
2211 * call into the dynamic linker and overwrite it.
2213 saved_msg = errmsg_save();
2215 STAILQ_FOREACH(elm, list, link) {
2216 if (root != NULL && (elm->obj->refcount != 1 ||
2217 objlist_find(&root->dagmembers, elm->obj) == NULL))
2219 /* Remove object from fini list to prevent recursive invocation. */
2220 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2222 * XXX: If a dlopen() call references an object while the
2223 * fini function is in progress, we might end up trying to
2224 * unload the referenced object in dlclose() or the object
2225 * won't be unloaded although its fini function has been
2228 lock_release(rtld_bind_lock, lockstate);
2231 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2232 * When this happens, DT_FINI_ARRAY is processed first.
2234 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2235 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2236 for (index = elm->obj->fini_array_num - 1; index >= 0;
2238 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2239 dbg("calling fini function for %s at %p",
2240 elm->obj->path, (void *)fini_addr[index]);
2241 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2242 (void *)fini_addr[index], 0, 0, elm->obj->path);
2243 call_initfini_pointer(elm->obj, fini_addr[index]);
2247 if (elm->obj->fini != (Elf_Addr)NULL) {
2248 dbg("calling fini function for %s at %p", elm->obj->path,
2249 (void *)elm->obj->fini);
2250 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2251 0, 0, elm->obj->path);
2252 call_initfini_pointer(elm->obj, elm->obj->fini);
2254 wlock_acquire(rtld_bind_lock, lockstate);
2255 /* No need to free anything if process is going down. */
2259 * We must restart the list traversal after every fini call
2260 * because a dlclose() call from the fini function or from
2261 * another thread might have modified the reference counts.
2265 } while (elm != NULL);
2266 errmsg_restore(saved_msg);
2270 * Call the initialization functions for each of the objects in
2271 * "list". All of the objects are expected to have non-NULL init
2275 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2280 Elf_Addr *init_addr;
2284 * Clean init_scanned flag so that objects can be rechecked and
2285 * possibly initialized earlier if any of vectors called below
2286 * cause the change by using dlopen.
2288 for (obj = obj_list; obj != NULL; obj = obj->next)
2289 obj->init_scanned = false;
2292 * Preserve the current error message since an init function might
2293 * call into the dynamic linker and overwrite it.
2295 saved_msg = errmsg_save();
2296 STAILQ_FOREACH(elm, list, link) {
2297 if (elm->obj->init_done) /* Initialized early. */
2300 * Race: other thread might try to use this object before current
2301 * one completes the initilization. Not much can be done here
2302 * without better locking.
2304 elm->obj->init_done = true;
2305 lock_release(rtld_bind_lock, lockstate);
2308 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2309 * When this happens, DT_INIT is processed first.
2311 if (elm->obj->init != (Elf_Addr)NULL) {
2312 dbg("calling init function for %s at %p", elm->obj->path,
2313 (void *)elm->obj->init);
2314 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2315 0, 0, elm->obj->path);
2316 call_initfini_pointer(elm->obj, elm->obj->init);
2318 init_addr = (Elf_Addr *)elm->obj->init_array;
2319 if (init_addr != NULL) {
2320 for (index = 0; index < elm->obj->init_array_num; index++) {
2321 if (init_addr[index] != 0 && init_addr[index] != 1) {
2322 dbg("calling init function for %s at %p", elm->obj->path,
2323 (void *)init_addr[index]);
2324 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2325 (void *)init_addr[index], 0, 0, elm->obj->path);
2326 call_init_pointer(elm->obj, init_addr[index]);
2330 wlock_acquire(rtld_bind_lock, lockstate);
2332 errmsg_restore(saved_msg);
2336 objlist_clear(Objlist *list)
2340 while (!STAILQ_EMPTY(list)) {
2341 elm = STAILQ_FIRST(list);
2342 STAILQ_REMOVE_HEAD(list, link);
2347 static Objlist_Entry *
2348 objlist_find(Objlist *list, const Obj_Entry *obj)
2352 STAILQ_FOREACH(elm, list, link)
2353 if (elm->obj == obj)
2359 objlist_init(Objlist *list)
2365 objlist_push_head(Objlist *list, Obj_Entry *obj)
2369 elm = NEW(Objlist_Entry);
2371 STAILQ_INSERT_HEAD(list, elm, link);
2375 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2379 elm = NEW(Objlist_Entry);
2381 STAILQ_INSERT_TAIL(list, elm, link);
2385 objlist_remove(Objlist *list, Obj_Entry *obj)
2389 if ((elm = objlist_find(list, obj)) != NULL) {
2390 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2396 * Relocate dag rooted in the specified object.
2397 * Returns 0 on success, or -1 on failure.
2401 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2402 int flags, RtldLockState *lockstate)
2408 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2409 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2418 * Relocate single object.
2419 * Returns 0 on success, or -1 on failure.
2422 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2423 int flags, RtldLockState *lockstate)
2428 obj->relocated = true;
2430 dbg("relocating \"%s\"", obj->path);
2432 if (obj->symtab == NULL || obj->strtab == NULL ||
2433 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2434 _rtld_error("%s: Shared object has no run-time symbol table",
2440 /* There are relocations to the write-protected text segment. */
2441 if (mprotect(obj->mapbase, obj->textsize,
2442 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2443 _rtld_error("%s: Cannot write-enable text segment: %s",
2444 obj->path, rtld_strerror(errno));
2449 /* Process the non-PLT relocations. */
2450 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2453 if (obj->textrel) { /* Re-protected the text segment. */
2454 if (mprotect(obj->mapbase, obj->textsize,
2455 PROT_READ|PROT_EXEC) == -1) {
2456 _rtld_error("%s: Cannot write-protect text segment: %s",
2457 obj->path, rtld_strerror(errno));
2463 /* Set the special PLT or GOT entries. */
2466 /* Process the PLT relocations. */
2467 if (reloc_plt(obj) == -1)
2469 /* Relocate the jump slots if we are doing immediate binding. */
2470 if (obj->bind_now || bind_now)
2471 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2474 if (obj->relro_size > 0) {
2475 if (mprotect(obj->relro_page, obj->relro_size,
2477 _rtld_error("%s: Cannot enforce relro protection: %s",
2478 obj->path, rtld_strerror(errno));
2484 * Set up the magic number and version in the Obj_Entry. These
2485 * were checked in the crt1.o from the original ElfKit, so we
2486 * set them for backward compatibility.
2488 obj->magic = RTLD_MAGIC;
2489 obj->version = RTLD_VERSION;
2495 * Relocate newly-loaded shared objects. The argument is a pointer to
2496 * the Obj_Entry for the first such object. All objects from the first
2497 * to the end of the list of objects are relocated. Returns 0 on success,
2501 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2502 int flags, RtldLockState *lockstate)
2507 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2508 error = relocate_object(obj, bind_now, rtldobj, flags,
2517 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2518 * referencing STT_GNU_IFUNC symbols is postponed till the other
2519 * relocations are done. The indirect functions specified as
2520 * ifunc are allowed to call other symbols, so we need to have
2521 * objects relocated before asking for resolution from indirects.
2523 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2524 * instead of the usual lazy handling of PLT slots. It is
2525 * consistent with how GNU does it.
2528 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2529 RtldLockState *lockstate)
2531 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2533 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2534 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2540 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2541 RtldLockState *lockstate)
2545 for (obj = first; obj != NULL; obj = obj->next) {
2546 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2553 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2554 RtldLockState *lockstate)
2558 STAILQ_FOREACH(elm, list, link) {
2559 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2567 * Cleanup procedure. It will be called (by the atexit mechanism) just
2568 * before the process exits.
2573 RtldLockState lockstate;
2575 wlock_acquire(rtld_bind_lock, &lockstate);
2577 objlist_call_fini(&list_fini, NULL, &lockstate);
2578 /* No need to remove the items from the list, since we are exiting. */
2579 if (!libmap_disable)
2581 lock_release(rtld_bind_lock, &lockstate);
2585 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2593 path += strspn(path, ":;");
2594 while (*path != '\0') {
2598 len = strcspn(path, ":;");
2600 trans = lm_findn(NULL, path, len);
2602 res = callback(trans, strlen(trans), arg);
2605 res = callback(path, len, arg);
2611 path += strspn(path, ":;");
2617 struct try_library_args {
2625 try_library_path(const char *dir, size_t dirlen, void *param)
2627 struct try_library_args *arg;
2630 if (*dir == '/' || trust) {
2633 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2636 pathname = arg->buffer;
2637 strncpy(pathname, dir, dirlen);
2638 pathname[dirlen] = '/';
2639 strcpy(pathname + dirlen + 1, arg->name);
2641 dbg(" Trying \"%s\"", pathname);
2642 if (access(pathname, F_OK) == 0) { /* We found it */
2643 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2644 strcpy(pathname, arg->buffer);
2652 search_library_path(const char *name, const char *path)
2655 struct try_library_args arg;
2661 arg.namelen = strlen(name);
2662 arg.buffer = xmalloc(PATH_MAX);
2663 arg.buflen = PATH_MAX;
2665 p = path_enumerate(path, try_library_path, &arg);
2673 dlclose(void *handle)
2676 RtldLockState lockstate;
2678 wlock_acquire(rtld_bind_lock, &lockstate);
2679 root = dlcheck(handle);
2681 lock_release(rtld_bind_lock, &lockstate);
2684 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2687 /* Unreference the object and its dependencies. */
2688 root->dl_refcount--;
2690 if (root->refcount == 1) {
2692 * The object will be no longer referenced, so we must unload it.
2693 * First, call the fini functions.
2695 objlist_call_fini(&list_fini, root, &lockstate);
2699 /* Finish cleaning up the newly-unreferenced objects. */
2700 GDB_STATE(RT_DELETE,&root->linkmap);
2701 unload_object(root);
2702 GDB_STATE(RT_CONSISTENT,NULL);
2706 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2707 lock_release(rtld_bind_lock, &lockstate);
2714 char *msg = error_message;
2715 error_message = NULL;
2720 * This function is deprecated and has no effect.
2723 dllockinit(void *context,
2724 void *(*lock_create)(void *context),
2725 void (*rlock_acquire)(void *lock),
2726 void (*wlock_acquire)(void *lock),
2727 void (*lock_release)(void *lock),
2728 void (*lock_destroy)(void *lock),
2729 void (*context_destroy)(void *context))
2731 static void *cur_context;
2732 static void (*cur_context_destroy)(void *);
2734 /* Just destroy the context from the previous call, if necessary. */
2735 if (cur_context_destroy != NULL)
2736 cur_context_destroy(cur_context);
2737 cur_context = context;
2738 cur_context_destroy = context_destroy;
2742 dlopen(const char *name, int mode)
2745 return (rtld_dlopen(name, -1, mode));
2749 fdlopen(int fd, int mode)
2752 return (rtld_dlopen(NULL, fd, mode));
2756 rtld_dlopen(const char *name, int fd, int mode)
2758 RtldLockState lockstate;
2761 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2762 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2763 if (ld_tracing != NULL) {
2764 rlock_acquire(rtld_bind_lock, &lockstate);
2765 if (sigsetjmp(lockstate.env, 0) != 0)
2766 lock_upgrade(rtld_bind_lock, &lockstate);
2767 environ = (char **)*get_program_var_addr("environ", &lockstate);
2768 lock_release(rtld_bind_lock, &lockstate);
2770 lo_flags = RTLD_LO_DLOPEN;
2771 if (mode & RTLD_NODELETE)
2772 lo_flags |= RTLD_LO_NODELETE;
2773 if (mode & RTLD_NOLOAD)
2774 lo_flags |= RTLD_LO_NOLOAD;
2775 if (ld_tracing != NULL)
2776 lo_flags |= RTLD_LO_TRACE;
2778 return (dlopen_object(name, fd, obj_main, lo_flags,
2779 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
2783 dlopen_cleanup(Obj_Entry *obj)
2788 if (obj->refcount == 0)
2793 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2794 int mode, RtldLockState *lockstate)
2796 Obj_Entry **old_obj_tail;
2799 RtldLockState mlockstate;
2802 objlist_init(&initlist);
2804 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
2805 wlock_acquire(rtld_bind_lock, &mlockstate);
2806 lockstate = &mlockstate;
2808 GDB_STATE(RT_ADD,NULL);
2810 old_obj_tail = obj_tail;
2812 if (name == NULL && fd == -1) {
2816 obj = load_object(name, fd, refobj, lo_flags);
2821 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2822 objlist_push_tail(&list_global, obj);
2823 if (*old_obj_tail != NULL) { /* We loaded something new. */
2824 assert(*old_obj_tail == obj);
2825 result = load_needed_objects(obj,
2826 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
2830 result = rtld_verify_versions(&obj->dagmembers);
2831 if (result != -1 && ld_tracing)
2833 if (result == -1 || relocate_object_dag(obj,
2834 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
2835 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2837 dlopen_cleanup(obj);
2839 } else if (lo_flags & RTLD_LO_EARLY) {
2841 * Do not call the init functions for early loaded
2842 * filtees. The image is still not initialized enough
2845 * Our object is found by the global object list and
2846 * will be ordered among all init calls done right
2847 * before transferring control to main.
2850 /* Make list of init functions to call. */
2851 initlist_add_objects(obj, &obj->next, &initlist);
2854 * Process all no_delete objects here, given them own
2855 * DAGs to prevent their dependencies from being unloaded.
2856 * This has to be done after we have loaded all of the
2857 * dependencies, so that we do not miss any.
2860 process_nodelete(obj);
2863 * Bump the reference counts for objects on this DAG. If
2864 * this is the first dlopen() call for the object that was
2865 * already loaded as a dependency, initialize the dag
2871 if ((lo_flags & RTLD_LO_TRACE) != 0)
2874 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2875 obj->z_nodelete) && !obj->ref_nodel) {
2876 dbg("obj %s nodelete", obj->path);
2878 obj->z_nodelete = obj->ref_nodel = true;
2882 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2884 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2886 if (!(lo_flags & RTLD_LO_EARLY)) {
2887 map_stacks_exec(lockstate);
2890 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
2891 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2893 objlist_clear(&initlist);
2894 dlopen_cleanup(obj);
2895 if (lockstate == &mlockstate)
2896 lock_release(rtld_bind_lock, lockstate);
2900 if (!(lo_flags & RTLD_LO_EARLY)) {
2901 /* Call the init functions. */
2902 objlist_call_init(&initlist, lockstate);
2904 objlist_clear(&initlist);
2905 if (lockstate == &mlockstate)
2906 lock_release(rtld_bind_lock, lockstate);
2909 trace_loaded_objects(obj);
2910 if (lockstate == &mlockstate)
2911 lock_release(rtld_bind_lock, lockstate);
2916 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
2920 const Obj_Entry *obj, *defobj;
2923 RtldLockState lockstate;
2931 symlook_init(&req, name);
2933 req.flags = flags | SYMLOOK_IN_PLT;
2934 req.lockstate = &lockstate;
2936 rlock_acquire(rtld_bind_lock, &lockstate);
2937 if (sigsetjmp(lockstate.env, 0) != 0)
2938 lock_upgrade(rtld_bind_lock, &lockstate);
2939 if (handle == NULL || handle == RTLD_NEXT ||
2940 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
2942 if ((obj = obj_from_addr(retaddr)) == NULL) {
2943 _rtld_error("Cannot determine caller's shared object");
2944 lock_release(rtld_bind_lock, &lockstate);
2947 if (handle == NULL) { /* Just the caller's shared object. */
2948 res = symlook_obj(&req, obj);
2951 defobj = req.defobj_out;
2953 } else if (handle == RTLD_NEXT || /* Objects after caller's */
2954 handle == RTLD_SELF) { /* ... caller included */
2955 if (handle == RTLD_NEXT)
2957 for (; obj != NULL; obj = obj->next) {
2958 res = symlook_obj(&req, obj);
2961 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
2963 defobj = req.defobj_out;
2964 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
2970 * Search the dynamic linker itself, and possibly resolve the
2971 * symbol from there. This is how the application links to
2972 * dynamic linker services such as dlopen.
2974 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2975 res = symlook_obj(&req, &obj_rtld);
2978 defobj = req.defobj_out;
2982 assert(handle == RTLD_DEFAULT);
2983 res = symlook_default(&req, obj);
2985 defobj = req.defobj_out;
2990 if ((obj = dlcheck(handle)) == NULL) {
2991 lock_release(rtld_bind_lock, &lockstate);
2995 donelist_init(&donelist);
2996 if (obj->mainprog) {
2997 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
2998 res = symlook_global(&req, &donelist);
3001 defobj = req.defobj_out;
3004 * Search the dynamic linker itself, and possibly resolve the
3005 * symbol from there. This is how the application links to
3006 * dynamic linker services such as dlopen.
3008 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3009 res = symlook_obj(&req, &obj_rtld);
3012 defobj = req.defobj_out;
3017 /* Search the whole DAG rooted at the given object. */
3018 res = symlook_list(&req, &obj->dagmembers, &donelist);
3021 defobj = req.defobj_out;
3027 lock_release(rtld_bind_lock, &lockstate);
3030 * The value required by the caller is derived from the value
3031 * of the symbol. For the ia64 architecture, we need to
3032 * construct a function descriptor which the caller can use to
3033 * call the function with the right 'gp' value. For other
3034 * architectures and for non-functions, the value is simply
3035 * the relocated value of the symbol.
3037 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3038 return (make_function_pointer(def, defobj));
3039 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3040 return (rtld_resolve_ifunc(defobj, def));
3041 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3043 return (__tls_get_addr(defobj->tlsindex, def->st_value));
3045 ti.ti_module = defobj->tlsindex;
3046 ti.ti_offset = def->st_value;
3047 return (__tls_get_addr(&ti));
3050 return (defobj->relocbase + def->st_value);
3053 _rtld_error("Undefined symbol \"%s\"", name);
3054 lock_release(rtld_bind_lock, &lockstate);
3059 dlsym(void *handle, const char *name)
3061 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3066 dlfunc(void *handle, const char *name)
3073 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3079 dlvsym(void *handle, const char *name, const char *version)
3083 ventry.name = version;
3085 ventry.hash = elf_hash(version);
3087 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3092 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3094 const Obj_Entry *obj;
3095 RtldLockState lockstate;
3097 rlock_acquire(rtld_bind_lock, &lockstate);
3098 obj = obj_from_addr(addr);
3100 _rtld_error("No shared object contains address");
3101 lock_release(rtld_bind_lock, &lockstate);
3104 rtld_fill_dl_phdr_info(obj, phdr_info);
3105 lock_release(rtld_bind_lock, &lockstate);
3110 dladdr(const void *addr, Dl_info *info)
3112 const Obj_Entry *obj;
3115 unsigned long symoffset;
3116 RtldLockState lockstate;
3118 rlock_acquire(rtld_bind_lock, &lockstate);
3119 obj = obj_from_addr(addr);
3121 _rtld_error("No shared object contains address");
3122 lock_release(rtld_bind_lock, &lockstate);
3125 info->dli_fname = obj->path;
3126 info->dli_fbase = obj->mapbase;
3127 info->dli_saddr = (void *)0;
3128 info->dli_sname = NULL;
3131 * Walk the symbol list looking for the symbol whose address is
3132 * closest to the address sent in.
3134 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3135 def = obj->symtab + symoffset;
3138 * For skip the symbol if st_shndx is either SHN_UNDEF or
3141 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3145 * If the symbol is greater than the specified address, or if it
3146 * is further away from addr than the current nearest symbol,
3149 symbol_addr = obj->relocbase + def->st_value;
3150 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3153 /* Update our idea of the nearest symbol. */
3154 info->dli_sname = obj->strtab + def->st_name;
3155 info->dli_saddr = symbol_addr;
3158 if (info->dli_saddr == addr)
3161 lock_release(rtld_bind_lock, &lockstate);
3166 dlinfo(void *handle, int request, void *p)
3168 const Obj_Entry *obj;
3169 RtldLockState lockstate;
3172 rlock_acquire(rtld_bind_lock, &lockstate);
3174 if (handle == NULL || handle == RTLD_SELF) {
3177 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3178 if ((obj = obj_from_addr(retaddr)) == NULL)
3179 _rtld_error("Cannot determine caller's shared object");
3181 obj = dlcheck(handle);
3184 lock_release(rtld_bind_lock, &lockstate);
3190 case RTLD_DI_LINKMAP:
3191 *((struct link_map const **)p) = &obj->linkmap;
3193 case RTLD_DI_ORIGIN:
3194 error = rtld_dirname(obj->path, p);
3197 case RTLD_DI_SERINFOSIZE:
3198 case RTLD_DI_SERINFO:
3199 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3203 _rtld_error("Invalid request %d passed to dlinfo()", request);
3207 lock_release(rtld_bind_lock, &lockstate);
3213 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3216 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3217 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
3218 STAILQ_FIRST(&obj->names)->name : obj->path;
3219 phdr_info->dlpi_phdr = obj->phdr;
3220 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3221 phdr_info->dlpi_tls_modid = obj->tlsindex;
3222 phdr_info->dlpi_tls_data = obj->tlsinit;
3223 phdr_info->dlpi_adds = obj_loads;
3224 phdr_info->dlpi_subs = obj_loads - obj_count;
3228 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3230 struct dl_phdr_info phdr_info;
3231 const Obj_Entry *obj;
3232 RtldLockState bind_lockstate, phdr_lockstate;
3235 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3236 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3240 for (obj = obj_list; obj != NULL; obj = obj->next) {
3241 rtld_fill_dl_phdr_info(obj, &phdr_info);
3242 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3246 lock_release(rtld_bind_lock, &bind_lockstate);
3247 lock_release(rtld_phdr_lock, &phdr_lockstate);
3253 fill_search_info(const char *dir, size_t dirlen, void *param)
3255 struct fill_search_info_args *arg;
3259 if (arg->request == RTLD_DI_SERINFOSIZE) {
3260 arg->serinfo->dls_cnt ++;
3261 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3263 struct dl_serpath *s_entry;
3265 s_entry = arg->serpath;
3266 s_entry->dls_name = arg->strspace;
3267 s_entry->dls_flags = arg->flags;
3269 strncpy(arg->strspace, dir, dirlen);
3270 arg->strspace[dirlen] = '\0';
3272 arg->strspace += dirlen + 1;
3280 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3282 struct dl_serinfo _info;
3283 struct fill_search_info_args args;
3285 args.request = RTLD_DI_SERINFOSIZE;
3286 args.serinfo = &_info;
3288 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3291 path_enumerate(obj->rpath, fill_search_info, &args);
3292 path_enumerate(ld_library_path, fill_search_info, &args);
3293 path_enumerate(obj->runpath, fill_search_info, &args);
3294 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3295 if (!obj->z_nodeflib)
3296 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3299 if (request == RTLD_DI_SERINFOSIZE) {
3300 info->dls_size = _info.dls_size;
3301 info->dls_cnt = _info.dls_cnt;
3305 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3306 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3310 args.request = RTLD_DI_SERINFO;
3311 args.serinfo = info;
3312 args.serpath = &info->dls_serpath[0];
3313 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3315 args.flags = LA_SER_RUNPATH;
3316 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3319 args.flags = LA_SER_LIBPATH;
3320 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3323 args.flags = LA_SER_RUNPATH;
3324 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3327 args.flags = LA_SER_CONFIG;
3328 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3332 args.flags = LA_SER_DEFAULT;
3333 if (!obj->z_nodeflib &&
3334 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3340 rtld_dirname(const char *path, char *bname)
3344 /* Empty or NULL string gets treated as "." */
3345 if (path == NULL || *path == '\0') {
3351 /* Strip trailing slashes */
3352 endp = path + strlen(path) - 1;
3353 while (endp > path && *endp == '/')
3356 /* Find the start of the dir */
3357 while (endp > path && *endp != '/')
3360 /* Either the dir is "/" or there are no slashes */
3362 bname[0] = *endp == '/' ? '/' : '.';
3368 } while (endp > path && *endp == '/');
3371 if (endp - path + 2 > PATH_MAX)
3373 _rtld_error("Filename is too long: %s", path);
3377 strncpy(bname, path, endp - path + 1);
3378 bname[endp - path + 1] = '\0';
3383 rtld_dirname_abs(const char *path, char *base)
3385 char base_rel[PATH_MAX];
3387 if (rtld_dirname(path, base) == -1)
3391 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
3392 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
3393 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
3395 strcpy(base, base_rel);
3400 linkmap_add(Obj_Entry *obj)
3402 struct link_map *l = &obj->linkmap;
3403 struct link_map *prev;
3405 obj->linkmap.l_name = obj->path;
3406 obj->linkmap.l_addr = obj->mapbase;
3407 obj->linkmap.l_ld = obj->dynamic;
3409 /* GDB needs load offset on MIPS to use the symbols */
3410 obj->linkmap.l_offs = obj->relocbase;
3413 if (r_debug.r_map == NULL) {
3419 * Scan to the end of the list, but not past the entry for the
3420 * dynamic linker, which we want to keep at the very end.
3422 for (prev = r_debug.r_map;
3423 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3424 prev = prev->l_next)
3427 /* Link in the new entry. */
3429 l->l_next = prev->l_next;
3430 if (l->l_next != NULL)
3431 l->l_next->l_prev = l;
3436 linkmap_delete(Obj_Entry *obj)
3438 struct link_map *l = &obj->linkmap;
3440 if (l->l_prev == NULL) {
3441 if ((r_debug.r_map = l->l_next) != NULL)
3442 l->l_next->l_prev = NULL;
3446 if ((l->l_prev->l_next = l->l_next) != NULL)
3447 l->l_next->l_prev = l->l_prev;
3451 * Function for the debugger to set a breakpoint on to gain control.
3453 * The two parameters allow the debugger to easily find and determine
3454 * what the runtime loader is doing and to whom it is doing it.
3456 * When the loadhook trap is hit (r_debug_state, set at program
3457 * initialization), the arguments can be found on the stack:
3459 * +8 struct link_map *m
3460 * +4 struct r_debug *rd
3464 r_debug_state(struct r_debug* rd, struct link_map *m)
3467 * The following is a hack to force the compiler to emit calls to
3468 * this function, even when optimizing. If the function is empty,
3469 * the compiler is not obliged to emit any code for calls to it,
3470 * even when marked __noinline. However, gdb depends on those
3473 __asm __volatile("" : : : "memory");
3477 * Get address of the pointer variable in the main program.
3478 * Prefer non-weak symbol over the weak one.
3480 static const void **
3481 get_program_var_addr(const char *name, RtldLockState *lockstate)
3486 symlook_init(&req, name);
3487 req.lockstate = lockstate;
3488 donelist_init(&donelist);
3489 if (symlook_global(&req, &donelist) != 0)
3491 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3492 return ((const void **)make_function_pointer(req.sym_out,
3494 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3495 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3497 return ((const void **)(req.defobj_out->relocbase +
3498 req.sym_out->st_value));
3502 * Set a pointer variable in the main program to the given value. This
3503 * is used to set key variables such as "environ" before any of the
3504 * init functions are called.
3507 set_program_var(const char *name, const void *value)
3511 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3512 dbg("\"%s\": *%p <-- %p", name, addr, value);
3518 * Search the global objects, including dependencies and main object,
3519 * for the given symbol.
3522 symlook_global(SymLook *req, DoneList *donelist)
3525 const Objlist_Entry *elm;
3528 symlook_init_from_req(&req1, req);
3530 /* Search all objects loaded at program start up. */
3531 if (req->defobj_out == NULL ||
3532 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3533 res = symlook_list(&req1, &list_main, donelist);
3534 if (res == 0 && (req->defobj_out == NULL ||
3535 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3536 req->sym_out = req1.sym_out;
3537 req->defobj_out = req1.defobj_out;
3538 assert(req->defobj_out != NULL);
3542 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3543 STAILQ_FOREACH(elm, &list_global, link) {
3544 if (req->defobj_out != NULL &&
3545 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3547 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3548 if (res == 0 && (req->defobj_out == NULL ||
3549 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3550 req->sym_out = req1.sym_out;
3551 req->defobj_out = req1.defobj_out;
3552 assert(req->defobj_out != NULL);
3556 return (req->sym_out != NULL ? 0 : ESRCH);
3560 * Given a symbol name in a referencing object, find the corresponding
3561 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3562 * no definition was found. Returns a pointer to the Obj_Entry of the
3563 * defining object via the reference parameter DEFOBJ_OUT.
3566 symlook_default(SymLook *req, const Obj_Entry *refobj)
3569 const Objlist_Entry *elm;
3573 donelist_init(&donelist);
3574 symlook_init_from_req(&req1, req);
3576 /* Look first in the referencing object if linked symbolically. */
3577 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3578 res = symlook_obj(&req1, refobj);
3580 req->sym_out = req1.sym_out;
3581 req->defobj_out = req1.defobj_out;
3582 assert(req->defobj_out != NULL);
3586 symlook_global(req, &donelist);
3588 /* Search all dlopened DAGs containing the referencing object. */
3589 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3590 if (req->sym_out != NULL &&
3591 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3593 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3594 if (res == 0 && (req->sym_out == NULL ||
3595 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3596 req->sym_out = req1.sym_out;
3597 req->defobj_out = req1.defobj_out;
3598 assert(req->defobj_out != NULL);
3603 * Search the dynamic linker itself, and possibly resolve the
3604 * symbol from there. This is how the application links to
3605 * dynamic linker services such as dlopen.
3607 if (req->sym_out == NULL ||
3608 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3609 res = symlook_obj(&req1, &obj_rtld);
3611 req->sym_out = req1.sym_out;
3612 req->defobj_out = req1.defobj_out;
3613 assert(req->defobj_out != NULL);
3617 return (req->sym_out != NULL ? 0 : ESRCH);
3621 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3624 const Obj_Entry *defobj;
3625 const Objlist_Entry *elm;
3631 STAILQ_FOREACH(elm, objlist, link) {
3632 if (donelist_check(dlp, elm->obj))
3634 symlook_init_from_req(&req1, req);
3635 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3636 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3638 defobj = req1.defobj_out;
3639 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3646 req->defobj_out = defobj;
3653 * Search the chain of DAGS cointed to by the given Needed_Entry
3654 * for a symbol of the given name. Each DAG is scanned completely
3655 * before advancing to the next one. Returns a pointer to the symbol,
3656 * or NULL if no definition was found.
3659 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3662 const Needed_Entry *n;
3663 const Obj_Entry *defobj;
3669 symlook_init_from_req(&req1, req);
3670 for (n = needed; n != NULL; n = n->next) {
3671 if (n->obj == NULL ||
3672 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3674 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3676 defobj = req1.defobj_out;
3677 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3683 req->defobj_out = defobj;
3690 * Search the symbol table of a single shared object for a symbol of
3691 * the given name and version, if requested. Returns a pointer to the
3692 * symbol, or NULL if no definition was found. If the object is
3693 * filter, return filtered symbol from filtee.
3695 * The symbol's hash value is passed in for efficiency reasons; that
3696 * eliminates many recomputations of the hash value.
3699 symlook_obj(SymLook *req, const Obj_Entry *obj)
3703 int flags, res, mres;
3706 * If there is at least one valid hash at this point, we prefer to
3707 * use the faster GNU version if available.
3709 if (obj->valid_hash_gnu)
3710 mres = symlook_obj1_gnu(req, obj);
3711 else if (obj->valid_hash_sysv)
3712 mres = symlook_obj1_sysv(req, obj);
3717 if (obj->needed_filtees != NULL) {
3718 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3719 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3720 donelist_init(&donelist);
3721 symlook_init_from_req(&req1, req);
3722 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3724 req->sym_out = req1.sym_out;
3725 req->defobj_out = req1.defobj_out;
3729 if (obj->needed_aux_filtees != NULL) {
3730 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3731 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3732 donelist_init(&donelist);
3733 symlook_init_from_req(&req1, req);
3734 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3736 req->sym_out = req1.sym_out;
3737 req->defobj_out = req1.defobj_out;
3745 /* Symbol match routine common to both hash functions */
3747 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3748 const unsigned long symnum)
3751 const Elf_Sym *symp;
3754 symp = obj->symtab + symnum;
3755 strp = obj->strtab + symp->st_name;
3757 switch (ELF_ST_TYPE(symp->st_info)) {
3763 if (symp->st_value == 0)
3767 if (symp->st_shndx != SHN_UNDEF)
3770 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3771 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3778 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3781 if (req->ventry == NULL) {
3782 if (obj->versyms != NULL) {
3783 verndx = VER_NDX(obj->versyms[symnum]);
3784 if (verndx > obj->vernum) {
3786 "%s: symbol %s references wrong version %d",
3787 obj->path, obj->strtab + symnum, verndx);
3791 * If we are not called from dlsym (i.e. this
3792 * is a normal relocation from unversioned
3793 * binary), accept the symbol immediately if
3794 * it happens to have first version after this
3795 * shared object became versioned. Otherwise,
3796 * if symbol is versioned and not hidden,
3797 * remember it. If it is the only symbol with
3798 * this name exported by the shared object, it
3799 * will be returned as a match by the calling
3800 * function. If symbol is global (verndx < 2)
3801 * accept it unconditionally.
3803 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3804 verndx == VER_NDX_GIVEN) {
3805 result->sym_out = symp;
3808 else if (verndx >= VER_NDX_GIVEN) {
3809 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
3811 if (result->vsymp == NULL)
3812 result->vsymp = symp;
3818 result->sym_out = symp;
3821 if (obj->versyms == NULL) {
3822 if (object_match_name(obj, req->ventry->name)) {
3823 _rtld_error("%s: object %s should provide version %s "
3824 "for symbol %s", obj_rtld.path, obj->path,
3825 req->ventry->name, obj->strtab + symnum);
3829 verndx = VER_NDX(obj->versyms[symnum]);
3830 if (verndx > obj->vernum) {
3831 _rtld_error("%s: symbol %s references wrong version %d",
3832 obj->path, obj->strtab + symnum, verndx);
3835 if (obj->vertab[verndx].hash != req->ventry->hash ||
3836 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3838 * Version does not match. Look if this is a
3839 * global symbol and if it is not hidden. If
3840 * global symbol (verndx < 2) is available,
3841 * use it. Do not return symbol if we are
3842 * called by dlvsym, because dlvsym looks for
3843 * a specific version and default one is not
3844 * what dlvsym wants.
3846 if ((req->flags & SYMLOOK_DLSYM) ||
3847 (verndx >= VER_NDX_GIVEN) ||
3848 (obj->versyms[symnum] & VER_NDX_HIDDEN))
3852 result->sym_out = symp;
3857 * Search for symbol using SysV hash function.
3858 * obj->buckets is known not to be NULL at this point; the test for this was
3859 * performed with the obj->valid_hash_sysv assignment.
3862 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
3864 unsigned long symnum;
3865 Sym_Match_Result matchres;
3867 matchres.sym_out = NULL;
3868 matchres.vsymp = NULL;
3869 matchres.vcount = 0;
3871 for (symnum = obj->buckets[req->hash % obj->nbuckets];
3872 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
3873 if (symnum >= obj->nchains)
3874 return (ESRCH); /* Bad object */
3876 if (matched_symbol(req, obj, &matchres, symnum)) {
3877 req->sym_out = matchres.sym_out;
3878 req->defobj_out = obj;
3882 if (matchres.vcount == 1) {
3883 req->sym_out = matchres.vsymp;
3884 req->defobj_out = obj;
3890 /* Search for symbol using GNU hash function */
3892 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
3894 Elf_Addr bloom_word;
3895 const Elf32_Word *hashval;
3897 Sym_Match_Result matchres;
3898 unsigned int h1, h2;
3899 unsigned long symnum;
3901 matchres.sym_out = NULL;
3902 matchres.vsymp = NULL;
3903 matchres.vcount = 0;
3905 /* Pick right bitmask word from Bloom filter array */
3906 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
3907 obj->maskwords_bm_gnu];
3909 /* Calculate modulus word size of gnu hash and its derivative */
3910 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
3911 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
3913 /* Filter out the "definitely not in set" queries */
3914 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
3917 /* Locate hash chain and corresponding value element*/
3918 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
3921 hashval = &obj->chain_zero_gnu[bucket];
3923 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
3924 symnum = hashval - obj->chain_zero_gnu;
3925 if (matched_symbol(req, obj, &matchres, symnum)) {
3926 req->sym_out = matchres.sym_out;
3927 req->defobj_out = obj;
3931 } while ((*hashval++ & 1) == 0);
3932 if (matchres.vcount == 1) {
3933 req->sym_out = matchres.vsymp;
3934 req->defobj_out = obj;
3941 trace_loaded_objects(Obj_Entry *obj)
3943 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
3946 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
3949 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
3950 fmt1 = "\t%o => %p (%x)\n";
3952 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
3953 fmt2 = "\t%o (%x)\n";
3955 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
3957 for (; obj; obj = obj->next) {
3958 Needed_Entry *needed;
3962 if (list_containers && obj->needed != NULL)
3963 rtld_printf("%s:\n", obj->path);
3964 for (needed = obj->needed; needed; needed = needed->next) {
3965 if (needed->obj != NULL) {
3966 if (needed->obj->traced && !list_containers)
3968 needed->obj->traced = true;
3969 path = needed->obj->path;
3973 name = (char *)obj->strtab + needed->name;
3974 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
3976 fmt = is_lib ? fmt1 : fmt2;
3977 while ((c = *fmt++) != '\0') {
4003 rtld_putstr(main_local);
4006 rtld_putstr(obj_main->path);
4013 rtld_printf("%d", sodp->sod_major);
4016 rtld_printf("%d", sodp->sod_minor);
4023 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4036 * Unload a dlopened object and its dependencies from memory and from
4037 * our data structures. It is assumed that the DAG rooted in the
4038 * object has already been unreferenced, and that the object has a
4039 * reference count of 0.
4042 unload_object(Obj_Entry *root)
4047 assert(root->refcount == 0);
4050 * Pass over the DAG removing unreferenced objects from
4051 * appropriate lists.
4053 unlink_object(root);
4055 /* Unmap all objects that are no longer referenced. */
4056 linkp = &obj_list->next;
4057 while ((obj = *linkp) != NULL) {
4058 if (obj->refcount == 0) {
4059 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4061 dbg("unloading \"%s\"", obj->path);
4062 unload_filtees(root);
4063 munmap(obj->mapbase, obj->mapsize);
4064 linkmap_delete(obj);
4075 unlink_object(Obj_Entry *root)
4079 if (root->refcount == 0) {
4080 /* Remove the object from the RTLD_GLOBAL list. */
4081 objlist_remove(&list_global, root);
4083 /* Remove the object from all objects' DAG lists. */
4084 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4085 objlist_remove(&elm->obj->dldags, root);
4086 if (elm->obj != root)
4087 unlink_object(elm->obj);
4093 ref_dag(Obj_Entry *root)
4097 assert(root->dag_inited);
4098 STAILQ_FOREACH(elm, &root->dagmembers, link)
4099 elm->obj->refcount++;
4103 unref_dag(Obj_Entry *root)
4107 assert(root->dag_inited);
4108 STAILQ_FOREACH(elm, &root->dagmembers, link)
4109 elm->obj->refcount--;
4113 * Common code for MD __tls_get_addr().
4115 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4117 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4119 Elf_Addr *newdtv, *dtv;
4120 RtldLockState lockstate;
4124 /* Check dtv generation in case new modules have arrived */
4125 if (dtv[0] != tls_dtv_generation) {
4126 wlock_acquire(rtld_bind_lock, &lockstate);
4127 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4129 if (to_copy > tls_max_index)
4130 to_copy = tls_max_index;
4131 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4132 newdtv[0] = tls_dtv_generation;
4133 newdtv[1] = tls_max_index;
4135 lock_release(rtld_bind_lock, &lockstate);
4136 dtv = *dtvp = newdtv;
4139 /* Dynamically allocate module TLS if necessary */
4140 if (dtv[index + 1] == 0) {
4141 /* Signal safe, wlock will block out signals. */
4142 wlock_acquire(rtld_bind_lock, &lockstate);
4143 if (!dtv[index + 1])
4144 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4145 lock_release(rtld_bind_lock, &lockstate);
4147 return ((void *)(dtv[index + 1] + offset));
4151 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4156 /* Check dtv generation in case new modules have arrived */
4157 if (__predict_true(dtv[0] == tls_dtv_generation &&
4158 dtv[index + 1] != 0))
4159 return ((void *)(dtv[index + 1] + offset));
4160 return (tls_get_addr_slow(dtvp, index, offset));
4163 #if defined(__arm__) || defined(__ia64__) || defined(__powerpc__)
4166 * Allocate Static TLS using the Variant I method.
4169 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4178 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4181 assert(tcbsize >= TLS_TCB_SIZE);
4182 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4183 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4185 if (oldtcb != NULL) {
4186 memcpy(tls, oldtcb, tls_static_space);
4189 /* Adjust the DTV. */
4191 for (i = 0; i < dtv[1]; i++) {
4192 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4193 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4194 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4198 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4200 dtv[0] = tls_dtv_generation;
4201 dtv[1] = tls_max_index;
4203 for (obj = objs; obj; obj = obj->next) {
4204 if (obj->tlsoffset > 0) {
4205 addr = (Elf_Addr)tls + obj->tlsoffset;
4206 if (obj->tlsinitsize > 0)
4207 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4208 if (obj->tlssize > obj->tlsinitsize)
4209 memset((void*) (addr + obj->tlsinitsize), 0,
4210 obj->tlssize - obj->tlsinitsize);
4211 dtv[obj->tlsindex + 1] = addr;
4220 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4223 Elf_Addr tlsstart, tlsend;
4226 assert(tcbsize >= TLS_TCB_SIZE);
4228 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4229 tlsend = tlsstart + tls_static_space;
4231 dtv = *(Elf_Addr **)tlsstart;
4233 for (i = 0; i < dtvsize; i++) {
4234 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4235 free((void*)dtv[i+2]);
4244 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \
4248 * Allocate Static TLS using the Variant II method.
4251 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4256 Elf_Addr *dtv, *olddtv;
4257 Elf_Addr segbase, oldsegbase, addr;
4260 size = round(tls_static_space, tcbalign);
4262 assert(tcbsize >= 2*sizeof(Elf_Addr));
4263 tls = xcalloc(1, size + tcbsize);
4264 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4266 segbase = (Elf_Addr)(tls + size);
4267 ((Elf_Addr*)segbase)[0] = segbase;
4268 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4270 dtv[0] = tls_dtv_generation;
4271 dtv[1] = tls_max_index;
4275 * Copy the static TLS block over whole.
4277 oldsegbase = (Elf_Addr) oldtls;
4278 memcpy((void *)(segbase - tls_static_space),
4279 (const void *)(oldsegbase - tls_static_space),
4283 * If any dynamic TLS blocks have been created tls_get_addr(),
4286 olddtv = ((Elf_Addr**)oldsegbase)[1];
4287 for (i = 0; i < olddtv[1]; i++) {
4288 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4289 dtv[i+2] = olddtv[i+2];
4295 * We assume that this block was the one we created with
4296 * allocate_initial_tls().
4298 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4300 for (obj = objs; obj; obj = obj->next) {
4301 if (obj->tlsoffset) {
4302 addr = segbase - obj->tlsoffset;
4303 memset((void*) (addr + obj->tlsinitsize),
4304 0, obj->tlssize - obj->tlsinitsize);
4306 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4307 dtv[obj->tlsindex + 1] = addr;
4312 return (void*) segbase;
4316 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4321 Elf_Addr tlsstart, tlsend;
4324 * Figure out the size of the initial TLS block so that we can
4325 * find stuff which ___tls_get_addr() allocated dynamically.
4327 size = round(tls_static_space, tcbalign);
4329 dtv = ((Elf_Addr**)tls)[1];
4331 tlsend = (Elf_Addr) tls;
4332 tlsstart = tlsend - size;
4333 for (i = 0; i < dtvsize; i++) {
4334 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) {
4335 free((void*) dtv[i+2]);
4339 free((void*) tlsstart);
4346 * Allocate TLS block for module with given index.
4349 allocate_module_tls(int index)
4354 for (obj = obj_list; obj; obj = obj->next) {
4355 if (obj->tlsindex == index)
4359 _rtld_error("Can't find module with TLS index %d", index);
4363 p = malloc(obj->tlssize);
4365 _rtld_error("Cannot allocate TLS block for index %d", index);
4368 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4369 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4375 allocate_tls_offset(Obj_Entry *obj)
4382 if (obj->tlssize == 0) {
4383 obj->tls_done = true;
4387 if (obj->tlsindex == 1)
4388 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4390 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4391 obj->tlssize, obj->tlsalign);
4394 * If we have already fixed the size of the static TLS block, we
4395 * must stay within that size. When allocating the static TLS, we
4396 * leave a small amount of space spare to be used for dynamically
4397 * loading modules which use static TLS.
4399 if (tls_static_space) {
4400 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4404 tls_last_offset = obj->tlsoffset = off;
4405 tls_last_size = obj->tlssize;
4406 obj->tls_done = true;
4412 free_tls_offset(Obj_Entry *obj)
4416 * If we were the last thing to allocate out of the static TLS
4417 * block, we give our space back to the 'allocator'. This is a
4418 * simplistic workaround to allow libGL.so.1 to be loaded and
4419 * unloaded multiple times.
4421 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4422 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4423 tls_last_offset -= obj->tlssize;
4429 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4432 RtldLockState lockstate;
4434 wlock_acquire(rtld_bind_lock, &lockstate);
4435 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4436 lock_release(rtld_bind_lock, &lockstate);
4441 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4443 RtldLockState lockstate;
4445 wlock_acquire(rtld_bind_lock, &lockstate);
4446 free_tls(tcb, tcbsize, tcbalign);
4447 lock_release(rtld_bind_lock, &lockstate);
4451 object_add_name(Obj_Entry *obj, const char *name)
4457 entry = malloc(sizeof(Name_Entry) + len);
4459 if (entry != NULL) {
4460 strcpy(entry->name, name);
4461 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4466 object_match_name(const Obj_Entry *obj, const char *name)
4470 STAILQ_FOREACH(entry, &obj->names, link) {
4471 if (strcmp(name, entry->name) == 0)
4478 locate_dependency(const Obj_Entry *obj, const char *name)
4480 const Objlist_Entry *entry;
4481 const Needed_Entry *needed;
4483 STAILQ_FOREACH(entry, &list_main, link) {
4484 if (object_match_name(entry->obj, name))
4488 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4489 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4490 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4492 * If there is DT_NEEDED for the name we are looking for,
4493 * we are all set. Note that object might not be found if
4494 * dependency was not loaded yet, so the function can
4495 * return NULL here. This is expected and handled
4496 * properly by the caller.
4498 return (needed->obj);
4501 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4507 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4508 const Elf_Vernaux *vna)
4510 const Elf_Verdef *vd;
4511 const char *vername;
4513 vername = refobj->strtab + vna->vna_name;
4514 vd = depobj->verdef;
4516 _rtld_error("%s: version %s required by %s not defined",
4517 depobj->path, vername, refobj->path);
4521 if (vd->vd_version != VER_DEF_CURRENT) {
4522 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4523 depobj->path, vd->vd_version);
4526 if (vna->vna_hash == vd->vd_hash) {
4527 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4528 ((char *)vd + vd->vd_aux);
4529 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4532 if (vd->vd_next == 0)
4534 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4536 if (vna->vna_flags & VER_FLG_WEAK)
4538 _rtld_error("%s: version %s required by %s not found",
4539 depobj->path, vername, refobj->path);
4544 rtld_verify_object_versions(Obj_Entry *obj)
4546 const Elf_Verneed *vn;
4547 const Elf_Verdef *vd;
4548 const Elf_Verdaux *vda;
4549 const Elf_Vernaux *vna;
4550 const Obj_Entry *depobj;
4551 int maxvernum, vernum;
4553 if (obj->ver_checked)
4555 obj->ver_checked = true;
4559 * Walk over defined and required version records and figure out
4560 * max index used by any of them. Do very basic sanity checking
4564 while (vn != NULL) {
4565 if (vn->vn_version != VER_NEED_CURRENT) {
4566 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4567 obj->path, vn->vn_version);
4570 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4572 vernum = VER_NEED_IDX(vna->vna_other);
4573 if (vernum > maxvernum)
4575 if (vna->vna_next == 0)
4577 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4579 if (vn->vn_next == 0)
4581 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4585 while (vd != NULL) {
4586 if (vd->vd_version != VER_DEF_CURRENT) {
4587 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4588 obj->path, vd->vd_version);
4591 vernum = VER_DEF_IDX(vd->vd_ndx);
4592 if (vernum > maxvernum)
4594 if (vd->vd_next == 0)
4596 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4603 * Store version information in array indexable by version index.
4604 * Verify that object version requirements are satisfied along the
4607 obj->vernum = maxvernum + 1;
4608 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4611 while (vd != NULL) {
4612 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4613 vernum = VER_DEF_IDX(vd->vd_ndx);
4614 assert(vernum <= maxvernum);
4615 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4616 obj->vertab[vernum].hash = vd->vd_hash;
4617 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4618 obj->vertab[vernum].file = NULL;
4619 obj->vertab[vernum].flags = 0;
4621 if (vd->vd_next == 0)
4623 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4627 while (vn != NULL) {
4628 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4631 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4633 if (check_object_provided_version(obj, depobj, vna))
4635 vernum = VER_NEED_IDX(vna->vna_other);
4636 assert(vernum <= maxvernum);
4637 obj->vertab[vernum].hash = vna->vna_hash;
4638 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4639 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4640 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4641 VER_INFO_HIDDEN : 0;
4642 if (vna->vna_next == 0)
4644 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4646 if (vn->vn_next == 0)
4648 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4654 rtld_verify_versions(const Objlist *objlist)
4656 Objlist_Entry *entry;
4660 STAILQ_FOREACH(entry, objlist, link) {
4662 * Skip dummy objects or objects that have their version requirements
4665 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4667 if (rtld_verify_object_versions(entry->obj) == -1) {
4669 if (ld_tracing == NULL)
4673 if (rc == 0 || ld_tracing != NULL)
4674 rc = rtld_verify_object_versions(&obj_rtld);
4679 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4684 vernum = VER_NDX(obj->versyms[symnum]);
4685 if (vernum >= obj->vernum) {
4686 _rtld_error("%s: symbol %s has wrong verneed value %d",
4687 obj->path, obj->strtab + symnum, vernum);
4688 } else if (obj->vertab[vernum].hash != 0) {
4689 return &obj->vertab[vernum];
4696 _rtld_get_stack_prot(void)
4699 return (stack_prot);
4703 map_stacks_exec(RtldLockState *lockstate)
4705 void (*thr_map_stacks_exec)(void);
4707 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4709 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4710 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4711 if (thr_map_stacks_exec != NULL) {
4712 stack_prot |= PROT_EXEC;
4713 thr_map_stacks_exec();
4718 symlook_init(SymLook *dst, const char *name)
4721 bzero(dst, sizeof(*dst));
4723 dst->hash = elf_hash(name);
4724 dst->hash_gnu = gnu_hash(name);
4728 symlook_init_from_req(SymLook *dst, const SymLook *src)
4731 dst->name = src->name;
4732 dst->hash = src->hash;
4733 dst->hash_gnu = src->hash_gnu;
4734 dst->ventry = src->ventry;
4735 dst->flags = src->flags;
4736 dst->defobj_out = NULL;
4737 dst->sym_out = NULL;
4738 dst->lockstate = src->lockstate;
4742 * Overrides for libc_pic-provided functions.
4746 __getosreldate(void)
4756 oid[1] = KERN_OSRELDATE;
4758 len = sizeof(osrel);
4759 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4760 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4772 void (*__cleanup)(void);
4773 int __isthreaded = 0;
4774 int _thread_autoinit_dummy_decl = 1;
4777 * No unresolved symbols for rtld.
4780 __pthread_cxa_finalize(struct dl_phdr_info *a)
4785 __stack_chk_fail(void)
4788 _rtld_error("stack overflow detected; terminated");
4791 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
4797 _rtld_error("buffer overflow detected; terminated");
4802 rtld_strerror(int errnum)
4805 if (errnum < 0 || errnum >= sys_nerr)
4806 return ("Unknown error");
4807 return (sys_errlist[errnum]);