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>.
37 #include <sys/param.h>
38 #include <sys/mount.h>
41 #include <sys/sysctl.h>
43 #include <sys/utsname.h>
44 #include <sys/ktrace.h>
61 #include "rtld_printf.h"
65 typedef void (*func_ptr_type)();
66 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
69 * Function declarations.
71 static const char *basename(const char *);
72 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
73 const Elf_Dyn **, const Elf_Dyn **);
74 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
76 static void digest_dynamic(Obj_Entry *, int);
77 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
78 static Obj_Entry *dlcheck(void *);
79 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
80 int lo_flags, int mode, RtldLockState *lockstate);
81 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
82 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
83 static bool donelist_check(DoneList *, const Obj_Entry *);
84 static void errmsg_restore(char *);
85 static char *errmsg_save(void);
86 static void *fill_search_info(const char *, size_t, void *);
87 static char *find_library(const char *, const Obj_Entry *, int *);
88 static const char *gethints(bool);
89 static void init_dag(Obj_Entry *);
90 static void init_pagesizes(Elf_Auxinfo **aux_info);
91 static void init_rtld(caddr_t, Elf_Auxinfo **);
92 static void initlist_add_neededs(Needed_Entry *, Objlist *);
93 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
94 static void linkmap_add(Obj_Entry *);
95 static void linkmap_delete(Obj_Entry *);
96 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
97 static void unload_filtees(Obj_Entry *);
98 static int load_needed_objects(Obj_Entry *, int);
99 static int load_preload_objects(void);
100 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
101 static void map_stacks_exec(RtldLockState *);
102 static Obj_Entry *obj_from_addr(const void *);
103 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
104 static void objlist_call_init(Objlist *, RtldLockState *);
105 static void objlist_clear(Objlist *);
106 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
107 static void objlist_init(Objlist *);
108 static void objlist_push_head(Objlist *, Obj_Entry *);
109 static void objlist_push_tail(Objlist *, Obj_Entry *);
110 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
111 static void objlist_remove(Objlist *, Obj_Entry *);
112 static int parse_libdir(const char *);
113 static void *path_enumerate(const char *, path_enum_proc, void *);
114 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
115 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
116 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
117 int flags, RtldLockState *lockstate);
118 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
120 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
121 int flags, RtldLockState *lockstate);
122 static int rtld_dirname(const char *, char *);
123 static int rtld_dirname_abs(const char *, char *);
124 static void *rtld_dlopen(const char *name, int fd, int mode);
125 static void rtld_exit(void);
126 static char *search_library_path(const char *, const char *);
127 static char *search_library_pathfds(const char *, const char *, int *);
128 static const void **get_program_var_addr(const char *, RtldLockState *);
129 static void set_program_var(const char *, const void *);
130 static int symlook_default(SymLook *, const Obj_Entry *refobj);
131 static int symlook_global(SymLook *, DoneList *);
132 static void symlook_init_from_req(SymLook *, const SymLook *);
133 static int symlook_list(SymLook *, const Objlist *, DoneList *);
134 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
135 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
136 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
137 static void trace_loaded_objects(Obj_Entry *);
138 static void unlink_object(Obj_Entry *);
139 static void unload_object(Obj_Entry *);
140 static void unref_dag(Obj_Entry *);
141 static void ref_dag(Obj_Entry *);
142 static char *origin_subst_one(Obj_Entry *, char *, const char *,
144 static char *origin_subst(Obj_Entry *, char *);
145 static bool obj_resolve_origin(Obj_Entry *obj);
146 static void preinit_main(void);
147 static int rtld_verify_versions(const Objlist *);
148 static int rtld_verify_object_versions(Obj_Entry *);
149 static void object_add_name(Obj_Entry *, const char *);
150 static int object_match_name(const Obj_Entry *, const char *);
151 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
152 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
153 struct dl_phdr_info *phdr_info);
154 static uint32_t gnu_hash(const char *);
155 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
156 const unsigned long);
158 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
159 void _r_debug_postinit(struct link_map *) __noinline __exported;
161 int __sys_openat(int, const char *, int, ...);
166 static char *error_message; /* Message for dlerror(), or NULL */
167 struct r_debug r_debug __exported; /* for GDB; */
168 static bool libmap_disable; /* Disable libmap */
169 static bool ld_loadfltr; /* Immediate filters processing */
170 static char *libmap_override; /* Maps to use in addition to libmap.conf */
171 static bool trust; /* False for setuid and setgid programs */
172 static bool dangerous_ld_env; /* True if environment variables have been
173 used to affect the libraries loaded */
174 static char *ld_bind_now; /* Environment variable for immediate binding */
175 static char *ld_debug; /* Environment variable for debugging */
176 static char *ld_library_path; /* Environment variable for search path */
177 static char *ld_library_dirs; /* Environment variable for library descriptors */
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 dlclose(void *) __exported;
208 char *dlerror(void) __exported;
209 void *dlopen(const char *, int) __exported;
210 void *fdlopen(int, int) __exported;
211 void *dlsym(void *, const char *) __exported;
212 dlfunc_t dlfunc(void *, const char *) __exported;
213 void *dlvsym(void *, const char *, const char *) __exported;
214 int dladdr(const void *, Dl_info *) __exported;
215 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
216 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
217 int dlinfo(void *, int , void *) __exported;
218 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
219 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
220 int _rtld_get_stack_prot(void) __exported;
221 int _rtld_is_dlopened(void *) __exported;
222 void _rtld_error(const char *, ...) __exported;
224 int npagesizes, osreldate;
227 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
229 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
230 static int max_stack_flags;
233 * Global declarations normally provided by crt1. The dynamic linker is
234 * not built with crt1, so we have to provide them ourselves.
240 * Used to pass argc, argv to init functions.
246 * Globals to control TLS allocation.
248 size_t tls_last_offset; /* Static TLS offset of last module */
249 size_t tls_last_size; /* Static TLS size of last module */
250 size_t tls_static_space; /* Static TLS space allocated */
251 size_t tls_static_max_align;
252 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
253 int tls_max_index = 1; /* Largest module index allocated */
255 bool ld_library_path_rpath = false;
258 * Globals for path names, and such
260 char *ld_path_elf_hints = _PATH_ELF_HINTS;
261 char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
262 char *ld_path_rtld = _PATH_RTLD;
263 char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
264 char *ld_env_prefix = LD_;
267 * Fill in a DoneList with an allocation large enough to hold all of
268 * the currently-loaded objects. Keep this as a macro since it calls
269 * alloca and we want that to occur within the scope of the caller.
271 #define donelist_init(dlp) \
272 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
273 assert((dlp)->objs != NULL), \
274 (dlp)->num_alloc = obj_count, \
277 #define UTRACE_DLOPEN_START 1
278 #define UTRACE_DLOPEN_STOP 2
279 #define UTRACE_DLCLOSE_START 3
280 #define UTRACE_DLCLOSE_STOP 4
281 #define UTRACE_LOAD_OBJECT 5
282 #define UTRACE_UNLOAD_OBJECT 6
283 #define UTRACE_ADD_RUNDEP 7
284 #define UTRACE_PRELOAD_FINISHED 8
285 #define UTRACE_INIT_CALL 9
286 #define UTRACE_FINI_CALL 10
287 #define UTRACE_DLSYM_START 11
288 #define UTRACE_DLSYM_STOP 12
291 char sig[4]; /* 'RTLD' */
294 void *mapbase; /* Used for 'parent' and 'init/fini' */
296 int refcnt; /* Used for 'mode' */
297 char name[MAXPATHLEN];
300 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
301 if (ld_utrace != NULL) \
302 ld_utrace_log(e, h, mb, ms, r, n); \
306 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
307 int refcnt, const char *name)
309 struct utrace_rtld ut;
317 ut.mapbase = mapbase;
318 ut.mapsize = mapsize;
320 bzero(ut.name, sizeof(ut.name));
322 strlcpy(ut.name, name, sizeof(ut.name));
323 utrace(&ut, sizeof(ut));
327 * Main entry point for dynamic linking. The first argument is the
328 * stack pointer. The stack is expected to be laid out as described
329 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
330 * Specifically, the stack pointer points to a word containing
331 * ARGC. Following that in the stack is a null-terminated sequence
332 * of pointers to argument strings. Then comes a null-terminated
333 * sequence of pointers to environment strings. Finally, there is a
334 * sequence of "auxiliary vector" entries.
336 * The second argument points to a place to store the dynamic linker's
337 * exit procedure pointer and the third to a place to store the main
340 * The return value is the main program's entry point.
343 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
345 Elf_Auxinfo *aux_info[AT_COUNT];
353 Objlist_Entry *entry;
355 Obj_Entry **preload_tail;
356 Obj_Entry *last_interposer;
358 RtldLockState lockstate;
359 char *library_path_rpath;
364 * On entry, the dynamic linker itself has not been relocated yet.
365 * Be very careful not to reference any global data until after
366 * init_rtld has returned. It is OK to reference file-scope statics
367 * and string constants, and to call static and global functions.
370 /* Find the auxiliary vector on the stack. */
373 sp += argc + 1; /* Skip over arguments and NULL terminator */
375 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
377 aux = (Elf_Auxinfo *) sp;
379 /* Digest the auxiliary vector. */
380 for (i = 0; i < AT_COUNT; i++)
382 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
383 if (auxp->a_type < AT_COUNT)
384 aux_info[auxp->a_type] = auxp;
387 /* Initialize and relocate ourselves. */
388 assert(aux_info[AT_BASE] != NULL);
389 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
391 __progname = obj_rtld.path;
392 argv0 = argv[0] != NULL ? argv[0] : "(null)";
397 if (aux_info[AT_CANARY] != NULL &&
398 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
399 i = aux_info[AT_CANARYLEN]->a_un.a_val;
400 if (i > sizeof(__stack_chk_guard))
401 i = sizeof(__stack_chk_guard);
402 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
407 len = sizeof(__stack_chk_guard);
408 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
409 len != sizeof(__stack_chk_guard)) {
410 /* If sysctl was unsuccessful, use the "terminator canary". */
411 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
412 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
413 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
414 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
418 trust = !issetugid();
420 ld_bind_now = getenv(LD_ "BIND_NOW");
422 * If the process is tainted, then we un-set the dangerous environment
423 * variables. The process will be marked as tainted until setuid(2)
424 * is called. If any child process calls setuid(2) we do not want any
425 * future processes to honor the potentially un-safe variables.
428 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
429 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBRARY_PATH_FDS") ||
430 unsetenv(LD_ "LIBMAP_DISABLE") ||
431 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
432 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) {
433 _rtld_error("environment corrupt; aborting");
437 ld_debug = getenv(LD_ "DEBUG");
438 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
439 libmap_override = getenv(LD_ "LIBMAP");
440 ld_library_path = getenv(LD_ "LIBRARY_PATH");
441 ld_library_dirs = getenv(LD_ "LIBRARY_PATH_FDS");
442 ld_preload = getenv(LD_ "PRELOAD");
443 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
444 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
445 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH");
446 if (library_path_rpath != NULL) {
447 if (library_path_rpath[0] == 'y' ||
448 library_path_rpath[0] == 'Y' ||
449 library_path_rpath[0] == '1')
450 ld_library_path_rpath = true;
452 ld_library_path_rpath = false;
454 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
455 (ld_library_path != NULL) || (ld_preload != NULL) ||
456 (ld_elf_hints_path != NULL) || ld_loadfltr;
457 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
458 ld_utrace = getenv(LD_ "UTRACE");
460 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
461 ld_elf_hints_path = ld_path_elf_hints;
463 if (ld_debug != NULL && *ld_debug != '\0')
465 dbg("%s is initialized, base address = %p", __progname,
466 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
467 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
468 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
470 dbg("initializing thread locks");
474 * Load the main program, or process its program header if it is
477 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
478 int fd = aux_info[AT_EXECFD]->a_un.a_val;
479 dbg("loading main program");
480 obj_main = map_object(fd, argv0, NULL);
482 if (obj_main == NULL)
484 max_stack_flags = obj->stack_flags;
485 } else { /* Main program already loaded. */
486 const Elf_Phdr *phdr;
490 dbg("processing main program's program header");
491 assert(aux_info[AT_PHDR] != NULL);
492 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
493 assert(aux_info[AT_PHNUM] != NULL);
494 phnum = aux_info[AT_PHNUM]->a_un.a_val;
495 assert(aux_info[AT_PHENT] != NULL);
496 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
497 assert(aux_info[AT_ENTRY] != NULL);
498 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
499 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
503 if (aux_info[AT_EXECPATH] != 0) {
505 char buf[MAXPATHLEN];
507 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
508 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
509 if (kexecpath[0] == '/')
510 obj_main->path = kexecpath;
511 else if (getcwd(buf, sizeof(buf)) == NULL ||
512 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
513 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
514 obj_main->path = xstrdup(argv0);
516 obj_main->path = xstrdup(buf);
518 dbg("No AT_EXECPATH");
519 obj_main->path = xstrdup(argv0);
521 dbg("obj_main path %s", obj_main->path);
522 obj_main->mainprog = true;
524 if (aux_info[AT_STACKPROT] != NULL &&
525 aux_info[AT_STACKPROT]->a_un.a_val != 0)
526 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
530 * Get the actual dynamic linker pathname from the executable if
531 * possible. (It should always be possible.) That ensures that
532 * gdb will find the right dynamic linker even if a non-standard
535 if (obj_main->interp != NULL &&
536 strcmp(obj_main->interp, obj_rtld.path) != 0) {
538 obj_rtld.path = xstrdup(obj_main->interp);
539 __progname = obj_rtld.path;
543 digest_dynamic(obj_main, 0);
544 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
545 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
546 obj_main->dynsymcount);
548 linkmap_add(obj_main);
549 linkmap_add(&obj_rtld);
551 /* Link the main program into the list of objects. */
552 *obj_tail = obj_main;
553 obj_tail = &obj_main->next;
557 /* Initialize a fake symbol for resolving undefined weak references. */
558 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
559 sym_zero.st_shndx = SHN_UNDEF;
560 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
563 libmap_disable = (bool)lm_init(libmap_override);
565 dbg("loading LD_PRELOAD libraries");
566 if (load_preload_objects() == -1)
568 preload_tail = obj_tail;
570 dbg("loading needed objects");
571 if (load_needed_objects(obj_main, 0) == -1)
574 /* Make a list of all objects loaded at startup. */
575 last_interposer = obj_main;
576 for (obj = obj_list; obj != NULL; obj = obj->next) {
577 if (obj->z_interpose && obj != obj_main) {
578 objlist_put_after(&list_main, last_interposer, obj);
579 last_interposer = obj;
581 objlist_push_tail(&list_main, obj);
586 dbg("checking for required versions");
587 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
590 if (ld_tracing) { /* We're done */
591 trace_loaded_objects(obj_main);
595 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
596 dump_relocations(obj_main);
601 * Processing tls relocations requires having the tls offsets
602 * initialized. Prepare offsets before starting initial
603 * relocation processing.
605 dbg("initializing initial thread local storage offsets");
606 STAILQ_FOREACH(entry, &list_main, link) {
608 * Allocate all the initial objects out of the static TLS
609 * block even if they didn't ask for it.
611 allocate_tls_offset(entry->obj);
614 if (relocate_objects(obj_main,
615 ld_bind_now != NULL && *ld_bind_now != '\0',
616 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
619 dbg("doing copy relocations");
620 if (do_copy_relocations(obj_main) == -1)
623 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
624 dump_relocations(obj_main);
629 * Setup TLS for main thread. This must be done after the
630 * relocations are processed, since tls initialization section
631 * might be the subject for relocations.
633 dbg("initializing initial thread local storage");
634 allocate_initial_tls(obj_list);
636 dbg("initializing key program variables");
637 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
638 set_program_var("environ", env);
639 set_program_var("__elf_aux_vector", aux);
641 /* Make a list of init functions to call. */
642 objlist_init(&initlist);
643 initlist_add_objects(obj_list, preload_tail, &initlist);
645 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
647 map_stacks_exec(NULL);
649 dbg("resolving ifuncs");
650 if (resolve_objects_ifunc(obj_main,
651 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
655 if (!obj_main->crt_no_init) {
657 * Make sure we don't call the main program's init and fini
658 * functions for binaries linked with old crt1 which calls
661 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
662 obj_main->preinit_array = obj_main->init_array =
663 obj_main->fini_array = (Elf_Addr)NULL;
666 wlock_acquire(rtld_bind_lock, &lockstate);
667 if (obj_main->crt_no_init)
669 objlist_call_init(&initlist, &lockstate);
670 _r_debug_postinit(&obj_main->linkmap);
671 objlist_clear(&initlist);
672 dbg("loading filtees");
673 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
674 if (ld_loadfltr || obj->z_loadfltr)
675 load_filtees(obj, 0, &lockstate);
677 lock_release(rtld_bind_lock, &lockstate);
679 dbg("transferring control to program entry point = %p", obj_main->entry);
681 /* Return the exit procedure and the program entry point. */
682 *exit_proc = rtld_exit;
684 return (func_ptr_type) obj_main->entry;
688 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
693 ptr = (void *)make_function_pointer(def, obj);
694 target = ((Elf_Addr (*)(void))ptr)();
695 return ((void *)target);
699 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
703 const Obj_Entry *defobj;
706 RtldLockState lockstate;
708 rlock_acquire(rtld_bind_lock, &lockstate);
709 if (sigsetjmp(lockstate.env, 0) != 0)
710 lock_upgrade(rtld_bind_lock, &lockstate);
712 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
714 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
716 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
717 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
721 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
722 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
724 target = (Elf_Addr)(defobj->relocbase + def->st_value);
726 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
727 defobj->strtab + def->st_name, basename(obj->path),
728 (void *)target, basename(defobj->path));
731 * Write the new contents for the jmpslot. Note that depending on
732 * architecture, the value which we need to return back to the
733 * lazy binding trampoline may or may not be the target
734 * address. The value returned from reloc_jmpslot() is the value
735 * that the trampoline needs.
737 target = reloc_jmpslot(where, target, defobj, obj, rel);
738 lock_release(rtld_bind_lock, &lockstate);
743 * Error reporting function. Use it like printf. If formats the message
744 * into a buffer, and sets things up so that the next call to dlerror()
745 * will return the message.
748 _rtld_error(const char *fmt, ...)
750 static char buf[512];
754 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
760 * Return a dynamically-allocated copy of the current error message, if any.
765 return error_message == NULL ? NULL : xstrdup(error_message);
769 * Restore the current error message from a copy which was previously saved
770 * by errmsg_save(). The copy is freed.
773 errmsg_restore(char *saved_msg)
775 if (saved_msg == NULL)
776 error_message = NULL;
778 _rtld_error("%s", saved_msg);
784 basename(const char *name)
786 const char *p = strrchr(name, '/');
787 return p != NULL ? p + 1 : name;
790 static struct utsname uts;
793 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
794 const char *subst, bool may_free)
796 char *p, *p1, *res, *resp;
797 int subst_len, kw_len, subst_count, old_len, new_len;
802 * First, count the number of the keyword occurences, to
803 * preallocate the final string.
805 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
812 * If the keyword is not found, just return.
814 * Return non-substituted string if resolution failed. We
815 * cannot do anything more reasonable, the failure mode of the
816 * caller is unresolved library anyway.
818 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
819 return (may_free ? real : xstrdup(real));
821 subst = obj->origin_path;
824 * There is indeed something to substitute. Calculate the
825 * length of the resulting string, and allocate it.
827 subst_len = strlen(subst);
828 old_len = strlen(real);
829 new_len = old_len + (subst_len - kw_len) * subst_count;
830 res = xmalloc(new_len + 1);
833 * Now, execute the substitution loop.
835 for (p = real, resp = res, *resp = '\0';;) {
838 /* Copy the prefix before keyword. */
839 memcpy(resp, p, p1 - p);
841 /* Keyword replacement. */
842 memcpy(resp, subst, subst_len);
850 /* Copy to the end of string and finish. */
858 origin_subst(Obj_Entry *obj, char *real)
860 char *res1, *res2, *res3, *res4;
862 if (obj == NULL || !trust)
863 return (xstrdup(real));
864 if (uts.sysname[0] == '\0') {
865 if (uname(&uts) != 0) {
866 _rtld_error("utsname failed: %d", errno);
870 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false);
871 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
872 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
873 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
880 const char *msg = dlerror();
884 rtld_fdputstr(STDERR_FILENO, msg);
885 rtld_fdputchar(STDERR_FILENO, '\n');
890 * Process a shared object's DYNAMIC section, and save the important
891 * information in its Obj_Entry structure.
894 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
895 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
898 Needed_Entry **needed_tail = &obj->needed;
899 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
900 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
901 const Elf_Hashelt *hashtab;
902 const Elf32_Word *hashval;
903 Elf32_Word bkt, nmaskwords;
905 int plttype = DT_REL;
911 obj->bind_now = false;
912 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
913 switch (dynp->d_tag) {
916 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
920 obj->relsize = dynp->d_un.d_val;
924 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
928 obj->pltrel = (const Elf_Rel *)
929 (obj->relocbase + dynp->d_un.d_ptr);
933 obj->pltrelsize = dynp->d_un.d_val;
937 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
941 obj->relasize = dynp->d_un.d_val;
945 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
949 plttype = dynp->d_un.d_val;
950 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
954 obj->symtab = (const Elf_Sym *)
955 (obj->relocbase + dynp->d_un.d_ptr);
959 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
963 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
967 obj->strsize = dynp->d_un.d_val;
971 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
976 obj->verneednum = dynp->d_un.d_val;
980 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
985 obj->verdefnum = dynp->d_un.d_val;
989 obj->versyms = (const Elf_Versym *)(obj->relocbase +
995 hashtab = (const Elf_Hashelt *)(obj->relocbase +
997 obj->nbuckets = hashtab[0];
998 obj->nchains = hashtab[1];
999 obj->buckets = hashtab + 2;
1000 obj->chains = obj->buckets + obj->nbuckets;
1001 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1002 obj->buckets != NULL;
1008 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1010 obj->nbuckets_gnu = hashtab[0];
1011 obj->symndx_gnu = hashtab[1];
1012 nmaskwords = hashtab[2];
1013 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1014 obj->maskwords_bm_gnu = nmaskwords - 1;
1015 obj->shift2_gnu = hashtab[3];
1016 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
1017 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1018 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1020 /* Number of bitmask words is required to be power of 2 */
1021 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1022 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1028 Needed_Entry *nep = NEW(Needed_Entry);
1029 nep->name = dynp->d_un.d_val;
1034 needed_tail = &nep->next;
1040 Needed_Entry *nep = NEW(Needed_Entry);
1041 nep->name = dynp->d_un.d_val;
1045 *needed_filtees_tail = nep;
1046 needed_filtees_tail = &nep->next;
1052 Needed_Entry *nep = NEW(Needed_Entry);
1053 nep->name = dynp->d_un.d_val;
1057 *needed_aux_filtees_tail = nep;
1058 needed_aux_filtees_tail = &nep->next;
1063 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1067 obj->textrel = true;
1071 obj->symbolic = true;
1076 * We have to wait until later to process this, because we
1077 * might not have gotten the address of the string table yet.
1087 *dyn_runpath = dynp;
1091 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1094 case DT_PREINIT_ARRAY:
1095 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1098 case DT_PREINIT_ARRAYSZ:
1099 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1103 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1106 case DT_INIT_ARRAYSZ:
1107 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1111 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1115 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1118 case DT_FINI_ARRAYSZ:
1119 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1123 * Don't process DT_DEBUG on MIPS as the dynamic section
1124 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1129 /* XXX - not implemented yet */
1131 dbg("Filling in DT_DEBUG entry");
1132 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1137 if (dynp->d_un.d_val & DF_ORIGIN)
1138 obj->z_origin = true;
1139 if (dynp->d_un.d_val & DF_SYMBOLIC)
1140 obj->symbolic = true;
1141 if (dynp->d_un.d_val & DF_TEXTREL)
1142 obj->textrel = true;
1143 if (dynp->d_un.d_val & DF_BIND_NOW)
1144 obj->bind_now = true;
1145 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1149 case DT_MIPS_LOCAL_GOTNO:
1150 obj->local_gotno = dynp->d_un.d_val;
1153 case DT_MIPS_SYMTABNO:
1154 obj->symtabno = dynp->d_un.d_val;
1157 case DT_MIPS_GOTSYM:
1158 obj->gotsym = dynp->d_un.d_val;
1161 case DT_MIPS_RLD_MAP:
1162 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1166 #ifdef __powerpc64__
1167 case DT_PPC64_GLINK:
1168 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1173 if (dynp->d_un.d_val & DF_1_NOOPEN)
1174 obj->z_noopen = true;
1175 if (dynp->d_un.d_val & DF_1_ORIGIN)
1176 obj->z_origin = true;
1177 if (dynp->d_un.d_val & DF_1_GLOBAL)
1178 obj->z_global = true;
1179 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1180 obj->bind_now = true;
1181 if (dynp->d_un.d_val & DF_1_NODELETE)
1182 obj->z_nodelete = true;
1183 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1184 obj->z_loadfltr = true;
1185 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1186 obj->z_interpose = true;
1187 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1188 obj->z_nodeflib = true;
1193 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1200 obj->traced = false;
1202 if (plttype == DT_RELA) {
1203 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1205 obj->pltrelasize = obj->pltrelsize;
1206 obj->pltrelsize = 0;
1209 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1210 if (obj->valid_hash_sysv)
1211 obj->dynsymcount = obj->nchains;
1212 else if (obj->valid_hash_gnu) {
1213 obj->dynsymcount = 0;
1214 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1215 if (obj->buckets_gnu[bkt] == 0)
1217 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1220 while ((*hashval++ & 1u) == 0);
1222 obj->dynsymcount += obj->symndx_gnu;
1227 obj_resolve_origin(Obj_Entry *obj)
1230 if (obj->origin_path != NULL)
1232 obj->origin_path = xmalloc(PATH_MAX);
1233 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1237 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1238 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1241 if (obj->z_origin && !obj_resolve_origin(obj))
1244 if (dyn_runpath != NULL) {
1245 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1246 obj->runpath = origin_subst(obj, obj->runpath);
1247 } else if (dyn_rpath != NULL) {
1248 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1249 obj->rpath = origin_subst(obj, obj->rpath);
1251 if (dyn_soname != NULL)
1252 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1256 digest_dynamic(Obj_Entry *obj, int early)
1258 const Elf_Dyn *dyn_rpath;
1259 const Elf_Dyn *dyn_soname;
1260 const Elf_Dyn *dyn_runpath;
1262 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1263 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1267 * Process a shared object's program header. This is used only for the
1268 * main program, when the kernel has already loaded the main program
1269 * into memory before calling the dynamic linker. It creates and
1270 * returns an Obj_Entry structure.
1273 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1276 const Elf_Phdr *phlimit = phdr + phnum;
1278 Elf_Addr note_start, note_end;
1282 for (ph = phdr; ph < phlimit; ph++) {
1283 if (ph->p_type != PT_PHDR)
1287 obj->phsize = ph->p_memsz;
1288 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1292 obj->stack_flags = PF_X | PF_R | PF_W;
1294 for (ph = phdr; ph < phlimit; ph++) {
1295 switch (ph->p_type) {
1298 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1302 if (nsegs == 0) { /* First load segment */
1303 obj->vaddrbase = trunc_page(ph->p_vaddr);
1304 obj->mapbase = obj->vaddrbase + obj->relocbase;
1305 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1307 } else { /* Last load segment */
1308 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1315 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1320 obj->tlssize = ph->p_memsz;
1321 obj->tlsalign = ph->p_align;
1322 obj->tlsinitsize = ph->p_filesz;
1323 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1327 obj->stack_flags = ph->p_flags;
1331 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1332 obj->relro_size = round_page(ph->p_memsz);
1336 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1337 note_end = note_start + ph->p_filesz;
1338 digest_notes(obj, note_start, note_end);
1343 _rtld_error("%s: too few PT_LOAD segments", path);
1352 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1354 const Elf_Note *note;
1355 const char *note_name;
1358 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1359 note = (const Elf_Note *)((const char *)(note + 1) +
1360 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1361 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1362 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1363 note->n_descsz != sizeof(int32_t))
1365 if (note->n_type != ABI_NOTETYPE &&
1366 note->n_type != CRT_NOINIT_NOTETYPE)
1368 note_name = (const char *)(note + 1);
1369 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1370 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1372 switch (note->n_type) {
1374 /* FreeBSD osrel note */
1375 p = (uintptr_t)(note + 1);
1376 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1377 obj->osrel = *(const int32_t *)(p);
1378 dbg("note osrel %d", obj->osrel);
1380 case CRT_NOINIT_NOTETYPE:
1381 /* FreeBSD 'crt does not call init' note */
1382 obj->crt_no_init = true;
1383 dbg("note crt_no_init");
1390 dlcheck(void *handle)
1394 for (obj = obj_list; obj != NULL; obj = obj->next)
1395 if (obj == (Obj_Entry *) handle)
1398 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1399 _rtld_error("Invalid shared object handle %p", handle);
1406 * If the given object is already in the donelist, return true. Otherwise
1407 * add the object to the list and return false.
1410 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1414 for (i = 0; i < dlp->num_used; i++)
1415 if (dlp->objs[i] == obj)
1418 * Our donelist allocation should always be sufficient. But if
1419 * our threads locking isn't working properly, more shared objects
1420 * could have been loaded since we allocated the list. That should
1421 * never happen, but we'll handle it properly just in case it does.
1423 if (dlp->num_used < dlp->num_alloc)
1424 dlp->objs[dlp->num_used++] = obj;
1429 * Hash function for symbol table lookup. Don't even think about changing
1430 * this. It is specified by the System V ABI.
1433 elf_hash(const char *name)
1435 const unsigned char *p = (const unsigned char *) name;
1436 unsigned long h = 0;
1439 while (*p != '\0') {
1440 h = (h << 4) + *p++;
1441 if ((g = h & 0xf0000000) != 0)
1449 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1450 * unsigned in case it's implemented with a wider type.
1453 gnu_hash(const char *s)
1459 for (c = *s; c != '\0'; c = *++s)
1461 return (h & 0xffffffff);
1466 * Find the library with the given name, and return its full pathname.
1467 * The returned string is dynamically allocated. Generates an error
1468 * message and returns NULL if the library cannot be found.
1470 * If the second argument is non-NULL, then it refers to an already-
1471 * loaded shared object, whose library search path will be searched.
1473 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1474 * descriptor (which is close-on-exec) will be passed out via the third
1477 * The search order is:
1478 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1479 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1481 * DT_RUNPATH in the referencing file
1482 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1484 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1486 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1489 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1493 bool nodeflib, objgiven;
1495 objgiven = refobj != NULL;
1496 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1497 if (xname[0] != '/' && !trust) {
1498 _rtld_error("Absolute pathname required for shared object \"%s\"",
1502 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1503 __DECONST(char *, xname)));
1506 if (libmap_disable || !objgiven ||
1507 (name = lm_find(refobj->path, xname)) == NULL)
1508 name = (char *)xname;
1510 dbg(" Searching for \"%s\"", name);
1513 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1514 * back to pre-conforming behaviour if user requested so with
1515 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1518 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1519 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1521 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1522 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL ||
1523 (pathname = search_library_path(name, gethints(false))) != NULL ||
1524 (pathname = search_library_path(name, ld_standard_library_path)) != NULL)
1527 nodeflib = objgiven ? refobj->z_nodeflib : false;
1529 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1530 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1531 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1532 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1534 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1535 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL ||
1536 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1537 (objgiven && !nodeflib &&
1538 (pathname = search_library_path(name, ld_standard_library_path)) != NULL))
1542 if (objgiven && refobj->path != NULL) {
1543 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1544 name, basename(refobj->path));
1546 _rtld_error("Shared object \"%s\" not found", name);
1552 * Given a symbol number in a referencing object, find the corresponding
1553 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1554 * no definition was found. Returns a pointer to the Obj_Entry of the
1555 * defining object via the reference parameter DEFOBJ_OUT.
1558 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1559 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1560 RtldLockState *lockstate)
1564 const Obj_Entry *defobj;
1570 * If we have already found this symbol, get the information from
1573 if (symnum >= refobj->dynsymcount)
1574 return NULL; /* Bad object */
1575 if (cache != NULL && cache[symnum].sym != NULL) {
1576 *defobj_out = cache[symnum].obj;
1577 return cache[symnum].sym;
1580 ref = refobj->symtab + symnum;
1581 name = refobj->strtab + ref->st_name;
1586 * We don't have to do a full scale lookup if the symbol is local.
1587 * We know it will bind to the instance in this load module; to
1588 * which we already have a pointer (ie ref). By not doing a lookup,
1589 * we not only improve performance, but it also avoids unresolvable
1590 * symbols when local symbols are not in the hash table. This has
1591 * been seen with the ia64 toolchain.
1593 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1594 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1595 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1598 symlook_init(&req, name);
1600 req.ventry = fetch_ventry(refobj, symnum);
1601 req.lockstate = lockstate;
1602 res = symlook_default(&req, refobj);
1605 defobj = req.defobj_out;
1613 * If we found no definition and the reference is weak, treat the
1614 * symbol as having the value zero.
1616 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1622 *defobj_out = defobj;
1623 /* Record the information in the cache to avoid subsequent lookups. */
1624 if (cache != NULL) {
1625 cache[symnum].sym = def;
1626 cache[symnum].obj = defobj;
1629 if (refobj != &obj_rtld)
1630 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1636 * Return the search path from the ldconfig hints file, reading it if
1637 * necessary. If nostdlib is true, then the default search paths are
1638 * not added to result.
1640 * Returns NULL if there are problems with the hints file,
1641 * or if the search path there is empty.
1644 gethints(bool nostdlib)
1646 static char *hints, *filtered_path;
1647 struct elfhints_hdr hdr;
1648 struct fill_search_info_args sargs, hargs;
1649 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1650 struct dl_serpath *SLPpath, *hintpath;
1652 unsigned int SLPndx, hintndx, fndx, fcount;
1657 /* First call, read the hints file */
1658 if (hints == NULL) {
1659 /* Keep from trying again in case the hints file is bad. */
1662 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1664 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1665 hdr.magic != ELFHINTS_MAGIC ||
1670 p = xmalloc(hdr.dirlistlen + 1);
1671 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1672 read(fd, p, hdr.dirlistlen + 1) !=
1673 (ssize_t)hdr.dirlistlen + 1) {
1683 * If caller agreed to receive list which includes the default
1684 * paths, we are done. Otherwise, if we still did not
1685 * calculated filtered result, do it now.
1688 return (hints[0] != '\0' ? hints : NULL);
1689 if (filtered_path != NULL)
1693 * Obtain the list of all configured search paths, and the
1694 * list of the default paths.
1696 * First estimate the size of the results.
1698 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1700 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1703 sargs.request = RTLD_DI_SERINFOSIZE;
1704 sargs.serinfo = &smeta;
1705 hargs.request = RTLD_DI_SERINFOSIZE;
1706 hargs.serinfo = &hmeta;
1708 path_enumerate(ld_standard_library_path, fill_search_info, &sargs);
1709 path_enumerate(p, fill_search_info, &hargs);
1711 SLPinfo = xmalloc(smeta.dls_size);
1712 hintinfo = xmalloc(hmeta.dls_size);
1715 * Next fetch both sets of paths.
1717 sargs.request = RTLD_DI_SERINFO;
1718 sargs.serinfo = SLPinfo;
1719 sargs.serpath = &SLPinfo->dls_serpath[0];
1720 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1722 hargs.request = RTLD_DI_SERINFO;
1723 hargs.serinfo = hintinfo;
1724 hargs.serpath = &hintinfo->dls_serpath[0];
1725 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1727 path_enumerate(ld_standard_library_path, fill_search_info, &sargs);
1728 path_enumerate(p, fill_search_info, &hargs);
1731 * Now calculate the difference between two sets, by excluding
1732 * standard paths from the full set.
1736 filtered_path = xmalloc(hdr.dirlistlen + 1);
1737 hintpath = &hintinfo->dls_serpath[0];
1738 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1740 SLPpath = &SLPinfo->dls_serpath[0];
1742 * Check each standard path against current.
1744 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1745 /* matched, skip the path */
1746 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1754 * Not matched against any standard path, add the path
1755 * to result. Separate consequtive paths with ':'.
1758 filtered_path[fndx] = ':';
1762 flen = strlen(hintpath->dls_name);
1763 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1766 filtered_path[fndx] = '\0';
1772 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1776 init_dag(Obj_Entry *root)
1778 const Needed_Entry *needed;
1779 const Objlist_Entry *elm;
1782 if (root->dag_inited)
1784 donelist_init(&donelist);
1786 /* Root object belongs to own DAG. */
1787 objlist_push_tail(&root->dldags, root);
1788 objlist_push_tail(&root->dagmembers, root);
1789 donelist_check(&donelist, root);
1792 * Add dependencies of root object to DAG in breadth order
1793 * by exploiting the fact that each new object get added
1794 * to the tail of the dagmembers list.
1796 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1797 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1798 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1800 objlist_push_tail(&needed->obj->dldags, root);
1801 objlist_push_tail(&root->dagmembers, needed->obj);
1804 root->dag_inited = true;
1808 process_z(Obj_Entry *root)
1810 const Objlist_Entry *elm;
1814 * Walk over object DAG and process every dependent object
1815 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
1816 * to grow their own DAG.
1818 * For DF_1_GLOBAL, DAG is required for symbol lookups in
1819 * symlook_global() to work.
1821 * For DF_1_NODELETE, the DAG should have its reference upped.
1823 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1827 if (obj->z_nodelete && !obj->ref_nodel) {
1828 dbg("obj %s -z nodelete", obj->path);
1831 obj->ref_nodel = true;
1833 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
1834 dbg("obj %s -z global", obj->path);
1835 objlist_push_tail(&list_global, obj);
1841 * Initialize the dynamic linker. The argument is the address at which
1842 * the dynamic linker has been mapped into memory. The primary task of
1843 * this function is to relocate the dynamic linker.
1846 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1848 Obj_Entry objtmp; /* Temporary rtld object */
1849 const Elf_Dyn *dyn_rpath;
1850 const Elf_Dyn *dyn_soname;
1851 const Elf_Dyn *dyn_runpath;
1853 #ifdef RTLD_INIT_PAGESIZES_EARLY
1854 /* The page size is required by the dynamic memory allocator. */
1855 init_pagesizes(aux_info);
1859 * Conjure up an Obj_Entry structure for the dynamic linker.
1861 * The "path" member can't be initialized yet because string constants
1862 * cannot yet be accessed. Below we will set it correctly.
1864 memset(&objtmp, 0, sizeof(objtmp));
1867 objtmp.mapbase = mapbase;
1869 objtmp.relocbase = mapbase;
1871 if (RTLD_IS_DYNAMIC()) {
1872 objtmp.dynamic = rtld_dynamic(&objtmp);
1873 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1874 assert(objtmp.needed == NULL);
1875 #if !defined(__mips__)
1876 /* MIPS has a bogus DT_TEXTREL. */
1877 assert(!objtmp.textrel);
1881 * Temporarily put the dynamic linker entry into the object list, so
1882 * that symbols can be found.
1885 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1888 /* Initialize the object list. */
1889 obj_tail = &obj_list;
1891 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1892 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1894 #ifndef RTLD_INIT_PAGESIZES_EARLY
1895 /* The page size is required by the dynamic memory allocator. */
1896 init_pagesizes(aux_info);
1899 if (aux_info[AT_OSRELDATE] != NULL)
1900 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1902 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1904 /* Replace the path with a dynamically allocated copy. */
1905 obj_rtld.path = xstrdup(ld_path_rtld);
1907 r_debug.r_brk = r_debug_state;
1908 r_debug.r_state = RT_CONSISTENT;
1912 * Retrieve the array of supported page sizes. The kernel provides the page
1913 * sizes in increasing order.
1916 init_pagesizes(Elf_Auxinfo **aux_info)
1918 static size_t psa[MAXPAGESIZES];
1922 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
1924 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
1925 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
1928 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
1931 /* As a fallback, retrieve the base page size. */
1932 size = sizeof(psa[0]);
1933 if (aux_info[AT_PAGESZ] != NULL) {
1934 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
1938 mib[1] = HW_PAGESIZE;
1942 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
1943 _rtld_error("sysctl for hw.pagesize(s) failed");
1949 npagesizes = size / sizeof(pagesizes[0]);
1950 /* Discard any invalid entries at the end of the array. */
1951 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
1956 * Add the init functions from a needed object list (and its recursive
1957 * needed objects) to "list". This is not used directly; it is a helper
1958 * function for initlist_add_objects(). The write lock must be held
1959 * when this function is called.
1962 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1964 /* Recursively process the successor needed objects. */
1965 if (needed->next != NULL)
1966 initlist_add_neededs(needed->next, list);
1968 /* Process the current needed object. */
1969 if (needed->obj != NULL)
1970 initlist_add_objects(needed->obj, &needed->obj->next, list);
1974 * Scan all of the DAGs rooted in the range of objects from "obj" to
1975 * "tail" and add their init functions to "list". This recurses over
1976 * the DAGs and ensure the proper init ordering such that each object's
1977 * needed libraries are initialized before the object itself. At the
1978 * same time, this function adds the objects to the global finalization
1979 * list "list_fini" in the opposite order. The write lock must be
1980 * held when this function is called.
1983 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1986 if (obj->init_scanned || obj->init_done)
1988 obj->init_scanned = true;
1990 /* Recursively process the successor objects. */
1991 if (&obj->next != tail)
1992 initlist_add_objects(obj->next, tail, list);
1994 /* Recursively process the needed objects. */
1995 if (obj->needed != NULL)
1996 initlist_add_neededs(obj->needed, list);
1997 if (obj->needed_filtees != NULL)
1998 initlist_add_neededs(obj->needed_filtees, list);
1999 if (obj->needed_aux_filtees != NULL)
2000 initlist_add_neededs(obj->needed_aux_filtees, list);
2002 /* Add the object to the init list. */
2003 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
2004 obj->init_array != (Elf_Addr)NULL)
2005 objlist_push_tail(list, obj);
2007 /* Add the object to the global fini list in the reverse order. */
2008 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2009 && !obj->on_fini_list) {
2010 objlist_push_head(&list_fini, obj);
2011 obj->on_fini_list = true;
2016 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2020 free_needed_filtees(Needed_Entry *n)
2022 Needed_Entry *needed, *needed1;
2024 for (needed = n; needed != NULL; needed = needed->next) {
2025 if (needed->obj != NULL) {
2026 dlclose(needed->obj);
2030 for (needed = n; needed != NULL; needed = needed1) {
2031 needed1 = needed->next;
2037 unload_filtees(Obj_Entry *obj)
2040 free_needed_filtees(obj->needed_filtees);
2041 obj->needed_filtees = NULL;
2042 free_needed_filtees(obj->needed_aux_filtees);
2043 obj->needed_aux_filtees = NULL;
2044 obj->filtees_loaded = false;
2048 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2049 RtldLockState *lockstate)
2052 for (; needed != NULL; needed = needed->next) {
2053 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2054 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2055 RTLD_LOCAL, lockstate);
2060 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2063 lock_restart_for_upgrade(lockstate);
2064 if (!obj->filtees_loaded) {
2065 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2066 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2067 obj->filtees_loaded = true;
2072 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2076 for (; needed != NULL; needed = needed->next) {
2077 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2078 flags & ~RTLD_LO_NOLOAD);
2079 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2086 * Given a shared object, traverse its list of needed objects, and load
2087 * each of them. Returns 0 on success. Generates an error message and
2088 * returns -1 on failure.
2091 load_needed_objects(Obj_Entry *first, int flags)
2095 for (obj = first; obj != NULL; obj = obj->next) {
2096 if (process_needed(obj, obj->needed, flags) == -1)
2103 load_preload_objects(void)
2105 char *p = ld_preload;
2107 static const char delim[] = " \t:;";
2112 p += strspn(p, delim);
2113 while (*p != '\0') {
2114 size_t len = strcspn(p, delim);
2119 obj = load_object(p, -1, NULL, 0);
2121 return -1; /* XXX - cleanup */
2122 obj->z_interpose = true;
2125 p += strspn(p, delim);
2127 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2132 printable_path(const char *path)
2135 return (path == NULL ? "<unknown>" : path);
2139 * Load a shared object into memory, if it is not already loaded. The
2140 * object may be specified by name or by user-supplied file descriptor
2141 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2144 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2148 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2157 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2158 if (object_match_name(obj, name))
2162 path = find_library(name, refobj, &fd);
2170 * search_library_pathfds() opens a fresh file descriptor for the
2171 * library, so there is no need to dup().
2173 } else if (fd_u == -1) {
2175 * If we didn't find a match by pathname, or the name is not
2176 * supplied, open the file and check again by device and inode.
2177 * This avoids false mismatches caused by multiple links or ".."
2180 * To avoid a race, we open the file and use fstat() rather than
2183 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2184 _rtld_error("Cannot open \"%s\"", path);
2189 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2191 _rtld_error("Cannot dup fd");
2196 if (fstat(fd, &sb) == -1) {
2197 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2202 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2203 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2205 if (obj != NULL && name != NULL) {
2206 object_add_name(obj, name);
2211 if (flags & RTLD_LO_NOLOAD) {
2217 /* First use of this object, so we must map it in */
2218 obj = do_load_object(fd, name, path, &sb, flags);
2227 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2234 * but first, make sure that environment variables haven't been
2235 * used to circumvent the noexec flag on a filesystem.
2237 if (dangerous_ld_env) {
2238 if (fstatfs(fd, &fs) != 0) {
2239 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2242 if (fs.f_flags & MNT_NOEXEC) {
2243 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2247 dbg("loading \"%s\"", printable_path(path));
2248 obj = map_object(fd, printable_path(path), sbp);
2253 * If DT_SONAME is present in the object, digest_dynamic2 already
2254 * added it to the object names.
2257 object_add_name(obj, name);
2259 digest_dynamic(obj, 0);
2260 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2261 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2262 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2264 dbg("refusing to load non-loadable \"%s\"", obj->path);
2265 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2266 munmap(obj->mapbase, obj->mapsize);
2271 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2273 obj_tail = &obj->next;
2276 linkmap_add(obj); /* for GDB & dlinfo() */
2277 max_stack_flags |= obj->stack_flags;
2279 dbg(" %p .. %p: %s", obj->mapbase,
2280 obj->mapbase + obj->mapsize - 1, obj->path);
2282 dbg(" WARNING: %s has impure text", obj->path);
2283 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2290 obj_from_addr(const void *addr)
2294 for (obj = obj_list; obj != NULL; obj = obj->next) {
2295 if (addr < (void *) obj->mapbase)
2297 if (addr < (void *) (obj->mapbase + obj->mapsize))
2306 Elf_Addr *preinit_addr;
2309 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2310 if (preinit_addr == NULL)
2313 for (index = 0; index < obj_main->preinit_array_num; index++) {
2314 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2315 dbg("calling preinit function for %s at %p", obj_main->path,
2316 (void *)preinit_addr[index]);
2317 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2318 0, 0, obj_main->path);
2319 call_init_pointer(obj_main, preinit_addr[index]);
2325 * Call the finalization functions for each of the objects in "list"
2326 * belonging to the DAG of "root" and referenced once. If NULL "root"
2327 * is specified, every finalization function will be called regardless
2328 * of the reference count and the list elements won't be freed. All of
2329 * the objects are expected to have non-NULL fini functions.
2332 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2336 Elf_Addr *fini_addr;
2339 assert(root == NULL || root->refcount == 1);
2342 * Preserve the current error message since a fini function might
2343 * call into the dynamic linker and overwrite it.
2345 saved_msg = errmsg_save();
2347 STAILQ_FOREACH(elm, list, link) {
2348 if (root != NULL && (elm->obj->refcount != 1 ||
2349 objlist_find(&root->dagmembers, elm->obj) == NULL))
2351 /* Remove object from fini list to prevent recursive invocation. */
2352 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2354 * XXX: If a dlopen() call references an object while the
2355 * fini function is in progress, we might end up trying to
2356 * unload the referenced object in dlclose() or the object
2357 * won't be unloaded although its fini function has been
2360 lock_release(rtld_bind_lock, lockstate);
2363 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2364 * When this happens, DT_FINI_ARRAY is processed first.
2366 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2367 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2368 for (index = elm->obj->fini_array_num - 1; index >= 0;
2370 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2371 dbg("calling fini function for %s at %p",
2372 elm->obj->path, (void *)fini_addr[index]);
2373 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2374 (void *)fini_addr[index], 0, 0, elm->obj->path);
2375 call_initfini_pointer(elm->obj, fini_addr[index]);
2379 if (elm->obj->fini != (Elf_Addr)NULL) {
2380 dbg("calling fini function for %s at %p", elm->obj->path,
2381 (void *)elm->obj->fini);
2382 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2383 0, 0, elm->obj->path);
2384 call_initfini_pointer(elm->obj, elm->obj->fini);
2386 wlock_acquire(rtld_bind_lock, lockstate);
2387 /* No need to free anything if process is going down. */
2391 * We must restart the list traversal after every fini call
2392 * because a dlclose() call from the fini function or from
2393 * another thread might have modified the reference counts.
2397 } while (elm != NULL);
2398 errmsg_restore(saved_msg);
2402 * Call the initialization functions for each of the objects in
2403 * "list". All of the objects are expected to have non-NULL init
2407 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2412 Elf_Addr *init_addr;
2416 * Clean init_scanned flag so that objects can be rechecked and
2417 * possibly initialized earlier if any of vectors called below
2418 * cause the change by using dlopen.
2420 for (obj = obj_list; obj != NULL; obj = obj->next)
2421 obj->init_scanned = false;
2424 * Preserve the current error message since an init function might
2425 * call into the dynamic linker and overwrite it.
2427 saved_msg = errmsg_save();
2428 STAILQ_FOREACH(elm, list, link) {
2429 if (elm->obj->init_done) /* Initialized early. */
2432 * Race: other thread might try to use this object before current
2433 * one completes the initilization. Not much can be done here
2434 * without better locking.
2436 elm->obj->init_done = true;
2437 lock_release(rtld_bind_lock, lockstate);
2440 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2441 * When this happens, DT_INIT is processed first.
2443 if (elm->obj->init != (Elf_Addr)NULL) {
2444 dbg("calling init function for %s at %p", elm->obj->path,
2445 (void *)elm->obj->init);
2446 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2447 0, 0, elm->obj->path);
2448 call_initfini_pointer(elm->obj, elm->obj->init);
2450 init_addr = (Elf_Addr *)elm->obj->init_array;
2451 if (init_addr != NULL) {
2452 for (index = 0; index < elm->obj->init_array_num; index++) {
2453 if (init_addr[index] != 0 && init_addr[index] != 1) {
2454 dbg("calling init function for %s at %p", elm->obj->path,
2455 (void *)init_addr[index]);
2456 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2457 (void *)init_addr[index], 0, 0, elm->obj->path);
2458 call_init_pointer(elm->obj, init_addr[index]);
2462 wlock_acquire(rtld_bind_lock, lockstate);
2464 errmsg_restore(saved_msg);
2468 objlist_clear(Objlist *list)
2472 while (!STAILQ_EMPTY(list)) {
2473 elm = STAILQ_FIRST(list);
2474 STAILQ_REMOVE_HEAD(list, link);
2479 static Objlist_Entry *
2480 objlist_find(Objlist *list, const Obj_Entry *obj)
2484 STAILQ_FOREACH(elm, list, link)
2485 if (elm->obj == obj)
2491 objlist_init(Objlist *list)
2497 objlist_push_head(Objlist *list, Obj_Entry *obj)
2501 elm = NEW(Objlist_Entry);
2503 STAILQ_INSERT_HEAD(list, elm, link);
2507 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2511 elm = NEW(Objlist_Entry);
2513 STAILQ_INSERT_TAIL(list, elm, link);
2517 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2519 Objlist_Entry *elm, *listelm;
2521 STAILQ_FOREACH(listelm, list, link) {
2522 if (listelm->obj == listobj)
2525 elm = NEW(Objlist_Entry);
2527 if (listelm != NULL)
2528 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2530 STAILQ_INSERT_TAIL(list, elm, link);
2534 objlist_remove(Objlist *list, Obj_Entry *obj)
2538 if ((elm = objlist_find(list, obj)) != NULL) {
2539 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2545 * Relocate dag rooted in the specified object.
2546 * Returns 0 on success, or -1 on failure.
2550 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2551 int flags, RtldLockState *lockstate)
2557 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2558 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2567 * Relocate single object.
2568 * Returns 0 on success, or -1 on failure.
2571 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2572 int flags, RtldLockState *lockstate)
2577 obj->relocated = true;
2579 dbg("relocating \"%s\"", obj->path);
2581 if (obj->symtab == NULL || obj->strtab == NULL ||
2582 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2583 _rtld_error("%s: Shared object has no run-time symbol table",
2589 /* There are relocations to the write-protected text segment. */
2590 if (mprotect(obj->mapbase, obj->textsize,
2591 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2592 _rtld_error("%s: Cannot write-enable text segment: %s",
2593 obj->path, rtld_strerror(errno));
2598 /* Process the non-PLT non-IFUNC relocations. */
2599 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2602 if (obj->textrel) { /* Re-protected the text segment. */
2603 if (mprotect(obj->mapbase, obj->textsize,
2604 PROT_READ|PROT_EXEC) == -1) {
2605 _rtld_error("%s: Cannot write-protect text segment: %s",
2606 obj->path, rtld_strerror(errno));
2611 /* Set the special PLT or GOT entries. */
2614 /* Process the PLT relocations. */
2615 if (reloc_plt(obj) == -1)
2617 /* Relocate the jump slots if we are doing immediate binding. */
2618 if (obj->bind_now || bind_now)
2619 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2623 * Process the non-PLT IFUNC relocations. The relocations are
2624 * processed in two phases, because IFUNC resolvers may
2625 * reference other symbols, which must be readily processed
2626 * before resolvers are called.
2628 if (obj->non_plt_gnu_ifunc &&
2629 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
2632 if (obj->relro_size > 0) {
2633 if (mprotect(obj->relro_page, obj->relro_size,
2635 _rtld_error("%s: Cannot enforce relro protection: %s",
2636 obj->path, rtld_strerror(errno));
2642 * Set up the magic number and version in the Obj_Entry. These
2643 * were checked in the crt1.o from the original ElfKit, so we
2644 * set them for backward compatibility.
2646 obj->magic = RTLD_MAGIC;
2647 obj->version = RTLD_VERSION;
2653 * Relocate newly-loaded shared objects. The argument is a pointer to
2654 * the Obj_Entry for the first such object. All objects from the first
2655 * to the end of the list of objects are relocated. Returns 0 on success,
2659 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2660 int flags, RtldLockState *lockstate)
2665 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2666 error = relocate_object(obj, bind_now, rtldobj, flags,
2675 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2676 * referencing STT_GNU_IFUNC symbols is postponed till the other
2677 * relocations are done. The indirect functions specified as
2678 * ifunc are allowed to call other symbols, so we need to have
2679 * objects relocated before asking for resolution from indirects.
2681 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2682 * instead of the usual lazy handling of PLT slots. It is
2683 * consistent with how GNU does it.
2686 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2687 RtldLockState *lockstate)
2689 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2691 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2692 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2698 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2699 RtldLockState *lockstate)
2703 for (obj = first; obj != NULL; obj = obj->next) {
2704 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2711 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2712 RtldLockState *lockstate)
2716 STAILQ_FOREACH(elm, list, link) {
2717 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2725 * Cleanup procedure. It will be called (by the atexit mechanism) just
2726 * before the process exits.
2731 RtldLockState lockstate;
2733 wlock_acquire(rtld_bind_lock, &lockstate);
2735 objlist_call_fini(&list_fini, NULL, &lockstate);
2736 /* No need to remove the items from the list, since we are exiting. */
2737 if (!libmap_disable)
2739 lock_release(rtld_bind_lock, &lockstate);
2743 * Iterate over a search path, translate each element, and invoke the
2744 * callback on the result.
2747 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2753 path += strspn(path, ":;");
2754 while (*path != '\0') {
2758 len = strcspn(path, ":;");
2759 trans = lm_findn(NULL, path, len);
2761 res = callback(trans, strlen(trans), arg);
2763 res = callback(path, len, arg);
2769 path += strspn(path, ":;");
2775 struct try_library_args {
2783 try_library_path(const char *dir, size_t dirlen, void *param)
2785 struct try_library_args *arg;
2788 if (*dir == '/' || trust) {
2791 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2794 pathname = arg->buffer;
2795 strncpy(pathname, dir, dirlen);
2796 pathname[dirlen] = '/';
2797 strcpy(pathname + dirlen + 1, arg->name);
2799 dbg(" Trying \"%s\"", pathname);
2800 if (access(pathname, F_OK) == 0) { /* We found it */
2801 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2802 strcpy(pathname, arg->buffer);
2810 search_library_path(const char *name, const char *path)
2813 struct try_library_args arg;
2819 arg.namelen = strlen(name);
2820 arg.buffer = xmalloc(PATH_MAX);
2821 arg.buflen = PATH_MAX;
2823 p = path_enumerate(path, try_library_path, &arg);
2832 * Finds the library with the given name using the directory descriptors
2833 * listed in the LD_LIBRARY_PATH_FDS environment variable.
2835 * Returns a freshly-opened close-on-exec file descriptor for the library,
2836 * or -1 if the library cannot be found.
2839 search_library_pathfds(const char *name, const char *path, int *fdp)
2841 char *envcopy, *fdstr, *found, *last_token;
2845 dbg("%s('%s', '%s', fdp)", __func__, name, path);
2847 /* Don't load from user-specified libdirs into setuid binaries. */
2851 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
2855 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
2856 if (name[0] == '/') {
2857 dbg("Absolute path (%s) passed to %s", name, __func__);
2862 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
2863 * copy of the path, as strtok_r rewrites separator tokens
2867 envcopy = xstrdup(path);
2868 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
2869 fdstr = strtok_r(NULL, ":", &last_token)) {
2870 dirfd = parse_libdir(fdstr);
2873 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
2876 len = strlen(fdstr) + strlen(name) + 3;
2877 found = xmalloc(len);
2878 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
2879 _rtld_error("error generating '%d/%s'",
2883 dbg("open('%s') => %d", found, fd);
2894 dlclose(void *handle)
2897 RtldLockState lockstate;
2899 wlock_acquire(rtld_bind_lock, &lockstate);
2900 root = dlcheck(handle);
2902 lock_release(rtld_bind_lock, &lockstate);
2905 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2908 /* Unreference the object and its dependencies. */
2909 root->dl_refcount--;
2911 if (root->refcount == 1) {
2913 * The object will be no longer referenced, so we must unload it.
2914 * First, call the fini functions.
2916 objlist_call_fini(&list_fini, root, &lockstate);
2920 /* Finish cleaning up the newly-unreferenced objects. */
2921 GDB_STATE(RT_DELETE,&root->linkmap);
2922 unload_object(root);
2923 GDB_STATE(RT_CONSISTENT,NULL);
2927 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2928 lock_release(rtld_bind_lock, &lockstate);
2935 char *msg = error_message;
2936 error_message = NULL;
2941 * This function is deprecated and has no effect.
2944 dllockinit(void *context,
2945 void *(*lock_create)(void *context),
2946 void (*rlock_acquire)(void *lock),
2947 void (*wlock_acquire)(void *lock),
2948 void (*lock_release)(void *lock),
2949 void (*lock_destroy)(void *lock),
2950 void (*context_destroy)(void *context))
2952 static void *cur_context;
2953 static void (*cur_context_destroy)(void *);
2955 /* Just destroy the context from the previous call, if necessary. */
2956 if (cur_context_destroy != NULL)
2957 cur_context_destroy(cur_context);
2958 cur_context = context;
2959 cur_context_destroy = context_destroy;
2963 dlopen(const char *name, int mode)
2966 return (rtld_dlopen(name, -1, mode));
2970 fdlopen(int fd, int mode)
2973 return (rtld_dlopen(NULL, fd, mode));
2977 rtld_dlopen(const char *name, int fd, int mode)
2979 RtldLockState lockstate;
2982 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2983 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2984 if (ld_tracing != NULL) {
2985 rlock_acquire(rtld_bind_lock, &lockstate);
2986 if (sigsetjmp(lockstate.env, 0) != 0)
2987 lock_upgrade(rtld_bind_lock, &lockstate);
2988 environ = (char **)*get_program_var_addr("environ", &lockstate);
2989 lock_release(rtld_bind_lock, &lockstate);
2991 lo_flags = RTLD_LO_DLOPEN;
2992 if (mode & RTLD_NODELETE)
2993 lo_flags |= RTLD_LO_NODELETE;
2994 if (mode & RTLD_NOLOAD)
2995 lo_flags |= RTLD_LO_NOLOAD;
2996 if (ld_tracing != NULL)
2997 lo_flags |= RTLD_LO_TRACE;
2999 return (dlopen_object(name, fd, obj_main, lo_flags,
3000 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3004 dlopen_cleanup(Obj_Entry *obj)
3009 if (obj->refcount == 0)
3014 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3015 int mode, RtldLockState *lockstate)
3017 Obj_Entry **old_obj_tail;
3020 RtldLockState mlockstate;
3023 objlist_init(&initlist);
3025 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3026 wlock_acquire(rtld_bind_lock, &mlockstate);
3027 lockstate = &mlockstate;
3029 GDB_STATE(RT_ADD,NULL);
3031 old_obj_tail = obj_tail;
3033 if (name == NULL && fd == -1) {
3037 obj = load_object(name, fd, refobj, lo_flags);
3042 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3043 objlist_push_tail(&list_global, obj);
3044 if (*old_obj_tail != NULL) { /* We loaded something new. */
3045 assert(*old_obj_tail == obj);
3046 result = load_needed_objects(obj,
3047 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
3051 result = rtld_verify_versions(&obj->dagmembers);
3052 if (result != -1 && ld_tracing)
3054 if (result == -1 || relocate_object_dag(obj,
3055 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3056 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3058 dlopen_cleanup(obj);
3060 } else if (lo_flags & RTLD_LO_EARLY) {
3062 * Do not call the init functions for early loaded
3063 * filtees. The image is still not initialized enough
3066 * Our object is found by the global object list and
3067 * will be ordered among all init calls done right
3068 * before transferring control to main.
3071 /* Make list of init functions to call. */
3072 initlist_add_objects(obj, &obj->next, &initlist);
3075 * Process all no_delete or global objects here, given
3076 * them own DAGs to prevent their dependencies from being
3077 * unloaded. This has to be done after we have loaded all
3078 * of the dependencies, so that we do not miss any.
3084 * Bump the reference counts for objects on this DAG. If
3085 * this is the first dlopen() call for the object that was
3086 * already loaded as a dependency, initialize the dag
3092 if ((lo_flags & RTLD_LO_TRACE) != 0)
3095 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3096 obj->z_nodelete) && !obj->ref_nodel) {
3097 dbg("obj %s nodelete", obj->path);
3099 obj->z_nodelete = obj->ref_nodel = true;
3103 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3105 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3107 if (!(lo_flags & RTLD_LO_EARLY)) {
3108 map_stacks_exec(lockstate);
3111 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3112 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3114 objlist_clear(&initlist);
3115 dlopen_cleanup(obj);
3116 if (lockstate == &mlockstate)
3117 lock_release(rtld_bind_lock, lockstate);
3121 if (!(lo_flags & RTLD_LO_EARLY)) {
3122 /* Call the init functions. */
3123 objlist_call_init(&initlist, lockstate);
3125 objlist_clear(&initlist);
3126 if (lockstate == &mlockstate)
3127 lock_release(rtld_bind_lock, lockstate);
3130 trace_loaded_objects(obj);
3131 if (lockstate == &mlockstate)
3132 lock_release(rtld_bind_lock, lockstate);
3137 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3141 const Obj_Entry *obj, *defobj;
3144 RtldLockState lockstate;
3151 symlook_init(&req, name);
3153 req.flags = flags | SYMLOOK_IN_PLT;
3154 req.lockstate = &lockstate;
3156 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3157 rlock_acquire(rtld_bind_lock, &lockstate);
3158 if (sigsetjmp(lockstate.env, 0) != 0)
3159 lock_upgrade(rtld_bind_lock, &lockstate);
3160 if (handle == NULL || handle == RTLD_NEXT ||
3161 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3163 if ((obj = obj_from_addr(retaddr)) == NULL) {
3164 _rtld_error("Cannot determine caller's shared object");
3165 lock_release(rtld_bind_lock, &lockstate);
3166 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3169 if (handle == NULL) { /* Just the caller's shared object. */
3170 res = symlook_obj(&req, obj);
3173 defobj = req.defobj_out;
3175 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3176 handle == RTLD_SELF) { /* ... caller included */
3177 if (handle == RTLD_NEXT)
3179 for (; obj != NULL; obj = obj->next) {
3180 res = symlook_obj(&req, obj);
3183 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3185 defobj = req.defobj_out;
3186 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3192 * Search the dynamic linker itself, and possibly resolve the
3193 * symbol from there. This is how the application links to
3194 * dynamic linker services such as dlopen.
3196 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3197 res = symlook_obj(&req, &obj_rtld);
3200 defobj = req.defobj_out;
3204 assert(handle == RTLD_DEFAULT);
3205 res = symlook_default(&req, obj);
3207 defobj = req.defobj_out;
3212 if ((obj = dlcheck(handle)) == NULL) {
3213 lock_release(rtld_bind_lock, &lockstate);
3214 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3218 donelist_init(&donelist);
3219 if (obj->mainprog) {
3220 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3221 res = symlook_global(&req, &donelist);
3224 defobj = req.defobj_out;
3227 * Search the dynamic linker itself, and possibly resolve the
3228 * symbol from there. This is how the application links to
3229 * dynamic linker services such as dlopen.
3231 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3232 res = symlook_obj(&req, &obj_rtld);
3235 defobj = req.defobj_out;
3240 /* Search the whole DAG rooted at the given object. */
3241 res = symlook_list(&req, &obj->dagmembers, &donelist);
3244 defobj = req.defobj_out;
3250 lock_release(rtld_bind_lock, &lockstate);
3253 * The value required by the caller is derived from the value
3254 * of the symbol. this is simply the relocated value of the
3257 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3258 sym = make_function_pointer(def, defobj);
3259 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3260 sym = rtld_resolve_ifunc(defobj, def);
3261 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3262 ti.ti_module = defobj->tlsindex;
3263 ti.ti_offset = def->st_value;
3264 sym = __tls_get_addr(&ti);
3266 sym = defobj->relocbase + def->st_value;
3267 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3271 _rtld_error("Undefined symbol \"%s\"", name);
3272 lock_release(rtld_bind_lock, &lockstate);
3273 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3278 dlsym(void *handle, const char *name)
3280 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3285 dlfunc(void *handle, const char *name)
3292 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3298 dlvsym(void *handle, const char *name, const char *version)
3302 ventry.name = version;
3304 ventry.hash = elf_hash(version);
3306 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3311 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3313 const Obj_Entry *obj;
3314 RtldLockState lockstate;
3316 rlock_acquire(rtld_bind_lock, &lockstate);
3317 obj = obj_from_addr(addr);
3319 _rtld_error("No shared object contains address");
3320 lock_release(rtld_bind_lock, &lockstate);
3323 rtld_fill_dl_phdr_info(obj, phdr_info);
3324 lock_release(rtld_bind_lock, &lockstate);
3329 dladdr(const void *addr, Dl_info *info)
3331 const Obj_Entry *obj;
3334 unsigned long symoffset;
3335 RtldLockState lockstate;
3337 rlock_acquire(rtld_bind_lock, &lockstate);
3338 obj = obj_from_addr(addr);
3340 _rtld_error("No shared object contains address");
3341 lock_release(rtld_bind_lock, &lockstate);
3344 info->dli_fname = obj->path;
3345 info->dli_fbase = obj->mapbase;
3346 info->dli_saddr = (void *)0;
3347 info->dli_sname = NULL;
3350 * Walk the symbol list looking for the symbol whose address is
3351 * closest to the address sent in.
3353 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3354 def = obj->symtab + symoffset;
3357 * For skip the symbol if st_shndx is either SHN_UNDEF or
3360 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3364 * If the symbol is greater than the specified address, or if it
3365 * is further away from addr than the current nearest symbol,
3368 symbol_addr = obj->relocbase + def->st_value;
3369 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3372 /* Update our idea of the nearest symbol. */
3373 info->dli_sname = obj->strtab + def->st_name;
3374 info->dli_saddr = symbol_addr;
3377 if (info->dli_saddr == addr)
3380 lock_release(rtld_bind_lock, &lockstate);
3385 dlinfo(void *handle, int request, void *p)
3387 const Obj_Entry *obj;
3388 RtldLockState lockstate;
3391 rlock_acquire(rtld_bind_lock, &lockstate);
3393 if (handle == NULL || handle == RTLD_SELF) {
3396 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3397 if ((obj = obj_from_addr(retaddr)) == NULL)
3398 _rtld_error("Cannot determine caller's shared object");
3400 obj = dlcheck(handle);
3403 lock_release(rtld_bind_lock, &lockstate);
3409 case RTLD_DI_LINKMAP:
3410 *((struct link_map const **)p) = &obj->linkmap;
3412 case RTLD_DI_ORIGIN:
3413 error = rtld_dirname(obj->path, p);
3416 case RTLD_DI_SERINFOSIZE:
3417 case RTLD_DI_SERINFO:
3418 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3422 _rtld_error("Invalid request %d passed to dlinfo()", request);
3426 lock_release(rtld_bind_lock, &lockstate);
3432 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3435 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3436 phdr_info->dlpi_name = obj->path;
3437 phdr_info->dlpi_phdr = obj->phdr;
3438 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3439 phdr_info->dlpi_tls_modid = obj->tlsindex;
3440 phdr_info->dlpi_tls_data = obj->tlsinit;
3441 phdr_info->dlpi_adds = obj_loads;
3442 phdr_info->dlpi_subs = obj_loads - obj_count;
3446 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3448 struct dl_phdr_info phdr_info;
3449 const Obj_Entry *obj;
3450 RtldLockState bind_lockstate, phdr_lockstate;
3453 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3454 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3458 for (obj = obj_list; obj != NULL; obj = obj->next) {
3459 rtld_fill_dl_phdr_info(obj, &phdr_info);
3460 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3465 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3466 error = callback(&phdr_info, sizeof(phdr_info), param);
3469 lock_release(rtld_bind_lock, &bind_lockstate);
3470 lock_release(rtld_phdr_lock, &phdr_lockstate);
3476 fill_search_info(const char *dir, size_t dirlen, void *param)
3478 struct fill_search_info_args *arg;
3482 if (arg->request == RTLD_DI_SERINFOSIZE) {
3483 arg->serinfo->dls_cnt ++;
3484 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3486 struct dl_serpath *s_entry;
3488 s_entry = arg->serpath;
3489 s_entry->dls_name = arg->strspace;
3490 s_entry->dls_flags = arg->flags;
3492 strncpy(arg->strspace, dir, dirlen);
3493 arg->strspace[dirlen] = '\0';
3495 arg->strspace += dirlen + 1;
3503 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3505 struct dl_serinfo _info;
3506 struct fill_search_info_args args;
3508 args.request = RTLD_DI_SERINFOSIZE;
3509 args.serinfo = &_info;
3511 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3514 path_enumerate(obj->rpath, fill_search_info, &args);
3515 path_enumerate(ld_library_path, fill_search_info, &args);
3516 path_enumerate(obj->runpath, fill_search_info, &args);
3517 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3518 if (!obj->z_nodeflib)
3519 path_enumerate(ld_standard_library_path, fill_search_info, &args);
3522 if (request == RTLD_DI_SERINFOSIZE) {
3523 info->dls_size = _info.dls_size;
3524 info->dls_cnt = _info.dls_cnt;
3528 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3529 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3533 args.request = RTLD_DI_SERINFO;
3534 args.serinfo = info;
3535 args.serpath = &info->dls_serpath[0];
3536 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3538 args.flags = LA_SER_RUNPATH;
3539 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3542 args.flags = LA_SER_LIBPATH;
3543 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3546 args.flags = LA_SER_RUNPATH;
3547 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3550 args.flags = LA_SER_CONFIG;
3551 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3555 args.flags = LA_SER_DEFAULT;
3556 if (!obj->z_nodeflib &&
3557 path_enumerate(ld_standard_library_path, fill_search_info, &args) != NULL)
3563 rtld_dirname(const char *path, char *bname)
3567 /* Empty or NULL string gets treated as "." */
3568 if (path == NULL || *path == '\0') {
3574 /* Strip trailing slashes */
3575 endp = path + strlen(path) - 1;
3576 while (endp > path && *endp == '/')
3579 /* Find the start of the dir */
3580 while (endp > path && *endp != '/')
3583 /* Either the dir is "/" or there are no slashes */
3585 bname[0] = *endp == '/' ? '/' : '.';
3591 } while (endp > path && *endp == '/');
3594 if (endp - path + 2 > PATH_MAX)
3596 _rtld_error("Filename is too long: %s", path);
3600 strncpy(bname, path, endp - path + 1);
3601 bname[endp - path + 1] = '\0';
3606 rtld_dirname_abs(const char *path, char *base)
3610 if (realpath(path, base) == NULL)
3612 dbg("%s -> %s", path, base);
3613 last = strrchr(base, '/');
3622 linkmap_add(Obj_Entry *obj)
3624 struct link_map *l = &obj->linkmap;
3625 struct link_map *prev;
3627 obj->linkmap.l_name = obj->path;
3628 obj->linkmap.l_addr = obj->mapbase;
3629 obj->linkmap.l_ld = obj->dynamic;
3631 /* GDB needs load offset on MIPS to use the symbols */
3632 obj->linkmap.l_offs = obj->relocbase;
3635 if (r_debug.r_map == NULL) {
3641 * Scan to the end of the list, but not past the entry for the
3642 * dynamic linker, which we want to keep at the very end.
3644 for (prev = r_debug.r_map;
3645 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3646 prev = prev->l_next)
3649 /* Link in the new entry. */
3651 l->l_next = prev->l_next;
3652 if (l->l_next != NULL)
3653 l->l_next->l_prev = l;
3658 linkmap_delete(Obj_Entry *obj)
3660 struct link_map *l = &obj->linkmap;
3662 if (l->l_prev == NULL) {
3663 if ((r_debug.r_map = l->l_next) != NULL)
3664 l->l_next->l_prev = NULL;
3668 if ((l->l_prev->l_next = l->l_next) != NULL)
3669 l->l_next->l_prev = l->l_prev;
3673 * Function for the debugger to set a breakpoint on to gain control.
3675 * The two parameters allow the debugger to easily find and determine
3676 * what the runtime loader is doing and to whom it is doing it.
3678 * When the loadhook trap is hit (r_debug_state, set at program
3679 * initialization), the arguments can be found on the stack:
3681 * +8 struct link_map *m
3682 * +4 struct r_debug *rd
3686 r_debug_state(struct r_debug* rd, struct link_map *m)
3689 * The following is a hack to force the compiler to emit calls to
3690 * this function, even when optimizing. If the function is empty,
3691 * the compiler is not obliged to emit any code for calls to it,
3692 * even when marked __noinline. However, gdb depends on those
3695 __compiler_membar();
3699 * A function called after init routines have completed. This can be used to
3700 * break before a program's entry routine is called, and can be used when
3701 * main is not available in the symbol table.
3704 _r_debug_postinit(struct link_map *m)
3707 /* See r_debug_state(). */
3708 __compiler_membar();
3712 * Get address of the pointer variable in the main program.
3713 * Prefer non-weak symbol over the weak one.
3715 static const void **
3716 get_program_var_addr(const char *name, RtldLockState *lockstate)
3721 symlook_init(&req, name);
3722 req.lockstate = lockstate;
3723 donelist_init(&donelist);
3724 if (symlook_global(&req, &donelist) != 0)
3726 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3727 return ((const void **)make_function_pointer(req.sym_out,
3729 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3730 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3732 return ((const void **)(req.defobj_out->relocbase +
3733 req.sym_out->st_value));
3737 * Set a pointer variable in the main program to the given value. This
3738 * is used to set key variables such as "environ" before any of the
3739 * init functions are called.
3742 set_program_var(const char *name, const void *value)
3746 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3747 dbg("\"%s\": *%p <-- %p", name, addr, value);
3753 * Search the global objects, including dependencies and main object,
3754 * for the given symbol.
3757 symlook_global(SymLook *req, DoneList *donelist)
3760 const Objlist_Entry *elm;
3763 symlook_init_from_req(&req1, req);
3765 /* Search all objects loaded at program start up. */
3766 if (req->defobj_out == NULL ||
3767 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3768 res = symlook_list(&req1, &list_main, donelist);
3769 if (res == 0 && (req->defobj_out == NULL ||
3770 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3771 req->sym_out = req1.sym_out;
3772 req->defobj_out = req1.defobj_out;
3773 assert(req->defobj_out != NULL);
3777 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3778 STAILQ_FOREACH(elm, &list_global, link) {
3779 if (req->defobj_out != NULL &&
3780 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3782 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3783 if (res == 0 && (req->defobj_out == NULL ||
3784 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3785 req->sym_out = req1.sym_out;
3786 req->defobj_out = req1.defobj_out;
3787 assert(req->defobj_out != NULL);
3791 return (req->sym_out != NULL ? 0 : ESRCH);
3795 * Given a symbol name in a referencing object, find the corresponding
3796 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3797 * no definition was found. Returns a pointer to the Obj_Entry of the
3798 * defining object via the reference parameter DEFOBJ_OUT.
3801 symlook_default(SymLook *req, const Obj_Entry *refobj)
3804 const Objlist_Entry *elm;
3808 donelist_init(&donelist);
3809 symlook_init_from_req(&req1, req);
3811 /* Look first in the referencing object if linked symbolically. */
3812 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3813 res = symlook_obj(&req1, refobj);
3815 req->sym_out = req1.sym_out;
3816 req->defobj_out = req1.defobj_out;
3817 assert(req->defobj_out != NULL);
3821 symlook_global(req, &donelist);
3823 /* Search all dlopened DAGs containing the referencing object. */
3824 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3825 if (req->sym_out != NULL &&
3826 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3828 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3829 if (res == 0 && (req->sym_out == NULL ||
3830 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3831 req->sym_out = req1.sym_out;
3832 req->defobj_out = req1.defobj_out;
3833 assert(req->defobj_out != NULL);
3838 * Search the dynamic linker itself, and possibly resolve the
3839 * symbol from there. This is how the application links to
3840 * dynamic linker services such as dlopen.
3842 if (req->sym_out == NULL ||
3843 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3844 res = symlook_obj(&req1, &obj_rtld);
3846 req->sym_out = req1.sym_out;
3847 req->defobj_out = req1.defobj_out;
3848 assert(req->defobj_out != NULL);
3852 return (req->sym_out != NULL ? 0 : ESRCH);
3856 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3859 const Obj_Entry *defobj;
3860 const Objlist_Entry *elm;
3866 STAILQ_FOREACH(elm, objlist, link) {
3867 if (donelist_check(dlp, elm->obj))
3869 symlook_init_from_req(&req1, req);
3870 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3871 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3873 defobj = req1.defobj_out;
3874 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3881 req->defobj_out = defobj;
3888 * Search the chain of DAGS cointed to by the given Needed_Entry
3889 * for a symbol of the given name. Each DAG is scanned completely
3890 * before advancing to the next one. Returns a pointer to the symbol,
3891 * or NULL if no definition was found.
3894 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3897 const Needed_Entry *n;
3898 const Obj_Entry *defobj;
3904 symlook_init_from_req(&req1, req);
3905 for (n = needed; n != NULL; n = n->next) {
3906 if (n->obj == NULL ||
3907 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3909 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3911 defobj = req1.defobj_out;
3912 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3918 req->defobj_out = defobj;
3925 * Search the symbol table of a single shared object for a symbol of
3926 * the given name and version, if requested. Returns a pointer to the
3927 * symbol, or NULL if no definition was found. If the object is
3928 * filter, return filtered symbol from filtee.
3930 * The symbol's hash value is passed in for efficiency reasons; that
3931 * eliminates many recomputations of the hash value.
3934 symlook_obj(SymLook *req, const Obj_Entry *obj)
3938 int flags, res, mres;
3941 * If there is at least one valid hash at this point, we prefer to
3942 * use the faster GNU version if available.
3944 if (obj->valid_hash_gnu)
3945 mres = symlook_obj1_gnu(req, obj);
3946 else if (obj->valid_hash_sysv)
3947 mres = symlook_obj1_sysv(req, obj);
3952 if (obj->needed_filtees != NULL) {
3953 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3954 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3955 donelist_init(&donelist);
3956 symlook_init_from_req(&req1, req);
3957 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3959 req->sym_out = req1.sym_out;
3960 req->defobj_out = req1.defobj_out;
3964 if (obj->needed_aux_filtees != NULL) {
3965 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3966 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3967 donelist_init(&donelist);
3968 symlook_init_from_req(&req1, req);
3969 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3971 req->sym_out = req1.sym_out;
3972 req->defobj_out = req1.defobj_out;
3980 /* Symbol match routine common to both hash functions */
3982 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3983 const unsigned long symnum)
3986 const Elf_Sym *symp;
3989 symp = obj->symtab + symnum;
3990 strp = obj->strtab + symp->st_name;
3992 switch (ELF_ST_TYPE(symp->st_info)) {
3998 if (symp->st_value == 0)
4002 if (symp->st_shndx != SHN_UNDEF)
4005 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4006 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4013 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4016 if (req->ventry == NULL) {
4017 if (obj->versyms != NULL) {
4018 verndx = VER_NDX(obj->versyms[symnum]);
4019 if (verndx > obj->vernum) {
4021 "%s: symbol %s references wrong version %d",
4022 obj->path, obj->strtab + symnum, verndx);
4026 * If we are not called from dlsym (i.e. this
4027 * is a normal relocation from unversioned
4028 * binary), accept the symbol immediately if
4029 * it happens to have first version after this
4030 * shared object became versioned. Otherwise,
4031 * if symbol is versioned and not hidden,
4032 * remember it. If it is the only symbol with
4033 * this name exported by the shared object, it
4034 * will be returned as a match by the calling
4035 * function. If symbol is global (verndx < 2)
4036 * accept it unconditionally.
4038 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4039 verndx == VER_NDX_GIVEN) {
4040 result->sym_out = symp;
4043 else if (verndx >= VER_NDX_GIVEN) {
4044 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4046 if (result->vsymp == NULL)
4047 result->vsymp = symp;
4053 result->sym_out = symp;
4056 if (obj->versyms == NULL) {
4057 if (object_match_name(obj, req->ventry->name)) {
4058 _rtld_error("%s: object %s should provide version %s "
4059 "for symbol %s", obj_rtld.path, obj->path,
4060 req->ventry->name, obj->strtab + symnum);
4064 verndx = VER_NDX(obj->versyms[symnum]);
4065 if (verndx > obj->vernum) {
4066 _rtld_error("%s: symbol %s references wrong version %d",
4067 obj->path, obj->strtab + symnum, verndx);
4070 if (obj->vertab[verndx].hash != req->ventry->hash ||
4071 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4073 * Version does not match. Look if this is a
4074 * global symbol and if it is not hidden. If
4075 * global symbol (verndx < 2) is available,
4076 * use it. Do not return symbol if we are
4077 * called by dlvsym, because dlvsym looks for
4078 * a specific version and default one is not
4079 * what dlvsym wants.
4081 if ((req->flags & SYMLOOK_DLSYM) ||
4082 (verndx >= VER_NDX_GIVEN) ||
4083 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4087 result->sym_out = symp;
4092 * Search for symbol using SysV hash function.
4093 * obj->buckets is known not to be NULL at this point; the test for this was
4094 * performed with the obj->valid_hash_sysv assignment.
4097 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4099 unsigned long symnum;
4100 Sym_Match_Result matchres;
4102 matchres.sym_out = NULL;
4103 matchres.vsymp = NULL;
4104 matchres.vcount = 0;
4106 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4107 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4108 if (symnum >= obj->nchains)
4109 return (ESRCH); /* Bad object */
4111 if (matched_symbol(req, obj, &matchres, symnum)) {
4112 req->sym_out = matchres.sym_out;
4113 req->defobj_out = obj;
4117 if (matchres.vcount == 1) {
4118 req->sym_out = matchres.vsymp;
4119 req->defobj_out = obj;
4125 /* Search for symbol using GNU hash function */
4127 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4129 Elf_Addr bloom_word;
4130 const Elf32_Word *hashval;
4132 Sym_Match_Result matchres;
4133 unsigned int h1, h2;
4134 unsigned long symnum;
4136 matchres.sym_out = NULL;
4137 matchres.vsymp = NULL;
4138 matchres.vcount = 0;
4140 /* Pick right bitmask word from Bloom filter array */
4141 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4142 obj->maskwords_bm_gnu];
4144 /* Calculate modulus word size of gnu hash and its derivative */
4145 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4146 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4148 /* Filter out the "definitely not in set" queries */
4149 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4152 /* Locate hash chain and corresponding value element*/
4153 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4156 hashval = &obj->chain_zero_gnu[bucket];
4158 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4159 symnum = hashval - obj->chain_zero_gnu;
4160 if (matched_symbol(req, obj, &matchres, symnum)) {
4161 req->sym_out = matchres.sym_out;
4162 req->defobj_out = obj;
4166 } while ((*hashval++ & 1) == 0);
4167 if (matchres.vcount == 1) {
4168 req->sym_out = matchres.vsymp;
4169 req->defobj_out = obj;
4176 trace_loaded_objects(Obj_Entry *obj)
4178 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4181 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
4184 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
4185 fmt1 = "\t%o => %p (%x)\n";
4187 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
4188 fmt2 = "\t%o (%x)\n";
4190 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
4192 for (; obj; obj = obj->next) {
4193 Needed_Entry *needed;
4197 if (list_containers && obj->needed != NULL)
4198 rtld_printf("%s:\n", obj->path);
4199 for (needed = obj->needed; needed; needed = needed->next) {
4200 if (needed->obj != NULL) {
4201 if (needed->obj->traced && !list_containers)
4203 needed->obj->traced = true;
4204 path = needed->obj->path;
4208 name = (char *)obj->strtab + needed->name;
4209 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4211 fmt = is_lib ? fmt1 : fmt2;
4212 while ((c = *fmt++) != '\0') {
4238 rtld_putstr(main_local);
4241 rtld_putstr(obj_main->path);
4248 rtld_printf("%d", sodp->sod_major);
4251 rtld_printf("%d", sodp->sod_minor);
4258 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4271 * Unload a dlopened object and its dependencies from memory and from
4272 * our data structures. It is assumed that the DAG rooted in the
4273 * object has already been unreferenced, and that the object has a
4274 * reference count of 0.
4277 unload_object(Obj_Entry *root)
4282 assert(root->refcount == 0);
4285 * Pass over the DAG removing unreferenced objects from
4286 * appropriate lists.
4288 unlink_object(root);
4290 /* Unmap all objects that are no longer referenced. */
4291 linkp = &obj_list->next;
4292 while ((obj = *linkp) != NULL) {
4293 if (obj->refcount == 0) {
4294 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4296 dbg("unloading \"%s\"", obj->path);
4297 unload_filtees(root);
4298 munmap(obj->mapbase, obj->mapsize);
4299 linkmap_delete(obj);
4310 unlink_object(Obj_Entry *root)
4314 if (root->refcount == 0) {
4315 /* Remove the object from the RTLD_GLOBAL list. */
4316 objlist_remove(&list_global, root);
4318 /* Remove the object from all objects' DAG lists. */
4319 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4320 objlist_remove(&elm->obj->dldags, root);
4321 if (elm->obj != root)
4322 unlink_object(elm->obj);
4328 ref_dag(Obj_Entry *root)
4332 assert(root->dag_inited);
4333 STAILQ_FOREACH(elm, &root->dagmembers, link)
4334 elm->obj->refcount++;
4338 unref_dag(Obj_Entry *root)
4342 assert(root->dag_inited);
4343 STAILQ_FOREACH(elm, &root->dagmembers, link)
4344 elm->obj->refcount--;
4348 * Common code for MD __tls_get_addr().
4350 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4352 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4354 Elf_Addr *newdtv, *dtv;
4355 RtldLockState lockstate;
4359 /* Check dtv generation in case new modules have arrived */
4360 if (dtv[0] != tls_dtv_generation) {
4361 wlock_acquire(rtld_bind_lock, &lockstate);
4362 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4364 if (to_copy > tls_max_index)
4365 to_copy = tls_max_index;
4366 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4367 newdtv[0] = tls_dtv_generation;
4368 newdtv[1] = tls_max_index;
4370 lock_release(rtld_bind_lock, &lockstate);
4371 dtv = *dtvp = newdtv;
4374 /* Dynamically allocate module TLS if necessary */
4375 if (dtv[index + 1] == 0) {
4376 /* Signal safe, wlock will block out signals. */
4377 wlock_acquire(rtld_bind_lock, &lockstate);
4378 if (!dtv[index + 1])
4379 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4380 lock_release(rtld_bind_lock, &lockstate);
4382 return ((void *)(dtv[index + 1] + offset));
4386 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4391 /* Check dtv generation in case new modules have arrived */
4392 if (__predict_true(dtv[0] == tls_dtv_generation &&
4393 dtv[index + 1] != 0))
4394 return ((void *)(dtv[index + 1] + offset));
4395 return (tls_get_addr_slow(dtvp, index, offset));
4398 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
4399 defined(__powerpc__)
4402 * Allocate Static TLS using the Variant I method.
4405 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4414 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4417 assert(tcbsize >= TLS_TCB_SIZE);
4418 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4419 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4421 if (oldtcb != NULL) {
4422 memcpy(tls, oldtcb, tls_static_space);
4425 /* Adjust the DTV. */
4427 for (i = 0; i < dtv[1]; i++) {
4428 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4429 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4430 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4434 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4436 dtv[0] = tls_dtv_generation;
4437 dtv[1] = tls_max_index;
4439 for (obj = objs; obj; obj = obj->next) {
4440 if (obj->tlsoffset > 0) {
4441 addr = (Elf_Addr)tls + obj->tlsoffset;
4442 if (obj->tlsinitsize > 0)
4443 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4444 if (obj->tlssize > obj->tlsinitsize)
4445 memset((void*) (addr + obj->tlsinitsize), 0,
4446 obj->tlssize - obj->tlsinitsize);
4447 dtv[obj->tlsindex + 1] = addr;
4456 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4459 Elf_Addr tlsstart, tlsend;
4462 assert(tcbsize >= TLS_TCB_SIZE);
4464 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4465 tlsend = tlsstart + tls_static_space;
4467 dtv = *(Elf_Addr **)tlsstart;
4469 for (i = 0; i < dtvsize; i++) {
4470 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4471 free((void*)dtv[i+2]);
4480 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4483 * Allocate Static TLS using the Variant II method.
4486 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4489 size_t size, ralign;
4491 Elf_Addr *dtv, *olddtv;
4492 Elf_Addr segbase, oldsegbase, addr;
4496 if (tls_static_max_align > ralign)
4497 ralign = tls_static_max_align;
4498 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4500 assert(tcbsize >= 2*sizeof(Elf_Addr));
4501 tls = malloc_aligned(size, ralign);
4502 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4504 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4505 ((Elf_Addr*)segbase)[0] = segbase;
4506 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4508 dtv[0] = tls_dtv_generation;
4509 dtv[1] = tls_max_index;
4513 * Copy the static TLS block over whole.
4515 oldsegbase = (Elf_Addr) oldtls;
4516 memcpy((void *)(segbase - tls_static_space),
4517 (const void *)(oldsegbase - tls_static_space),
4521 * If any dynamic TLS blocks have been created tls_get_addr(),
4524 olddtv = ((Elf_Addr**)oldsegbase)[1];
4525 for (i = 0; i < olddtv[1]; i++) {
4526 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4527 dtv[i+2] = olddtv[i+2];
4533 * We assume that this block was the one we created with
4534 * allocate_initial_tls().
4536 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4538 for (obj = objs; obj; obj = obj->next) {
4539 if (obj->tlsoffset) {
4540 addr = segbase - obj->tlsoffset;
4541 memset((void*) (addr + obj->tlsinitsize),
4542 0, obj->tlssize - obj->tlsinitsize);
4544 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4545 dtv[obj->tlsindex + 1] = addr;
4550 return (void*) segbase;
4554 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4557 size_t size, ralign;
4559 Elf_Addr tlsstart, tlsend;
4562 * Figure out the size of the initial TLS block so that we can
4563 * find stuff which ___tls_get_addr() allocated dynamically.
4566 if (tls_static_max_align > ralign)
4567 ralign = tls_static_max_align;
4568 size = round(tls_static_space, ralign);
4570 dtv = ((Elf_Addr**)tls)[1];
4572 tlsend = (Elf_Addr) tls;
4573 tlsstart = tlsend - size;
4574 for (i = 0; i < dtvsize; i++) {
4575 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4576 free_aligned((void *)dtv[i + 2]);
4580 free_aligned((void *)tlsstart);
4587 * Allocate TLS block for module with given index.
4590 allocate_module_tls(int index)
4595 for (obj = obj_list; obj; obj = obj->next) {
4596 if (obj->tlsindex == index)
4600 _rtld_error("Can't find module with TLS index %d", index);
4604 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4605 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4606 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4612 allocate_tls_offset(Obj_Entry *obj)
4619 if (obj->tlssize == 0) {
4620 obj->tls_done = true;
4624 if (tls_last_offset == 0)
4625 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4627 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4628 obj->tlssize, obj->tlsalign);
4631 * If we have already fixed the size of the static TLS block, we
4632 * must stay within that size. When allocating the static TLS, we
4633 * leave a small amount of space spare to be used for dynamically
4634 * loading modules which use static TLS.
4636 if (tls_static_space != 0) {
4637 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4639 } else if (obj->tlsalign > tls_static_max_align) {
4640 tls_static_max_align = obj->tlsalign;
4643 tls_last_offset = obj->tlsoffset = off;
4644 tls_last_size = obj->tlssize;
4645 obj->tls_done = true;
4651 free_tls_offset(Obj_Entry *obj)
4655 * If we were the last thing to allocate out of the static TLS
4656 * block, we give our space back to the 'allocator'. This is a
4657 * simplistic workaround to allow libGL.so.1 to be loaded and
4658 * unloaded multiple times.
4660 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4661 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4662 tls_last_offset -= obj->tlssize;
4668 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4671 RtldLockState lockstate;
4673 wlock_acquire(rtld_bind_lock, &lockstate);
4674 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4675 lock_release(rtld_bind_lock, &lockstate);
4680 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4682 RtldLockState lockstate;
4684 wlock_acquire(rtld_bind_lock, &lockstate);
4685 free_tls(tcb, tcbsize, tcbalign);
4686 lock_release(rtld_bind_lock, &lockstate);
4690 object_add_name(Obj_Entry *obj, const char *name)
4696 entry = malloc(sizeof(Name_Entry) + len);
4698 if (entry != NULL) {
4699 strcpy(entry->name, name);
4700 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4705 object_match_name(const Obj_Entry *obj, const char *name)
4709 STAILQ_FOREACH(entry, &obj->names, link) {
4710 if (strcmp(name, entry->name) == 0)
4717 locate_dependency(const Obj_Entry *obj, const char *name)
4719 const Objlist_Entry *entry;
4720 const Needed_Entry *needed;
4722 STAILQ_FOREACH(entry, &list_main, link) {
4723 if (object_match_name(entry->obj, name))
4727 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4728 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4729 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4731 * If there is DT_NEEDED for the name we are looking for,
4732 * we are all set. Note that object might not be found if
4733 * dependency was not loaded yet, so the function can
4734 * return NULL here. This is expected and handled
4735 * properly by the caller.
4737 return (needed->obj);
4740 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4746 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4747 const Elf_Vernaux *vna)
4749 const Elf_Verdef *vd;
4750 const char *vername;
4752 vername = refobj->strtab + vna->vna_name;
4753 vd = depobj->verdef;
4755 _rtld_error("%s: version %s required by %s not defined",
4756 depobj->path, vername, refobj->path);
4760 if (vd->vd_version != VER_DEF_CURRENT) {
4761 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4762 depobj->path, vd->vd_version);
4765 if (vna->vna_hash == vd->vd_hash) {
4766 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4767 ((char *)vd + vd->vd_aux);
4768 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4771 if (vd->vd_next == 0)
4773 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4775 if (vna->vna_flags & VER_FLG_WEAK)
4777 _rtld_error("%s: version %s required by %s not found",
4778 depobj->path, vername, refobj->path);
4783 rtld_verify_object_versions(Obj_Entry *obj)
4785 const Elf_Verneed *vn;
4786 const Elf_Verdef *vd;
4787 const Elf_Verdaux *vda;
4788 const Elf_Vernaux *vna;
4789 const Obj_Entry *depobj;
4790 int maxvernum, vernum;
4792 if (obj->ver_checked)
4794 obj->ver_checked = true;
4798 * Walk over defined and required version records and figure out
4799 * max index used by any of them. Do very basic sanity checking
4803 while (vn != NULL) {
4804 if (vn->vn_version != VER_NEED_CURRENT) {
4805 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4806 obj->path, vn->vn_version);
4809 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4811 vernum = VER_NEED_IDX(vna->vna_other);
4812 if (vernum > maxvernum)
4814 if (vna->vna_next == 0)
4816 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4818 if (vn->vn_next == 0)
4820 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4824 while (vd != NULL) {
4825 if (vd->vd_version != VER_DEF_CURRENT) {
4826 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4827 obj->path, vd->vd_version);
4830 vernum = VER_DEF_IDX(vd->vd_ndx);
4831 if (vernum > maxvernum)
4833 if (vd->vd_next == 0)
4835 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4842 * Store version information in array indexable by version index.
4843 * Verify that object version requirements are satisfied along the
4846 obj->vernum = maxvernum + 1;
4847 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4850 while (vd != NULL) {
4851 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4852 vernum = VER_DEF_IDX(vd->vd_ndx);
4853 assert(vernum <= maxvernum);
4854 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4855 obj->vertab[vernum].hash = vd->vd_hash;
4856 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4857 obj->vertab[vernum].file = NULL;
4858 obj->vertab[vernum].flags = 0;
4860 if (vd->vd_next == 0)
4862 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4866 while (vn != NULL) {
4867 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4870 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4872 if (check_object_provided_version(obj, depobj, vna))
4874 vernum = VER_NEED_IDX(vna->vna_other);
4875 assert(vernum <= maxvernum);
4876 obj->vertab[vernum].hash = vna->vna_hash;
4877 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4878 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4879 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4880 VER_INFO_HIDDEN : 0;
4881 if (vna->vna_next == 0)
4883 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4885 if (vn->vn_next == 0)
4887 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4893 rtld_verify_versions(const Objlist *objlist)
4895 Objlist_Entry *entry;
4899 STAILQ_FOREACH(entry, objlist, link) {
4901 * Skip dummy objects or objects that have their version requirements
4904 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4906 if (rtld_verify_object_versions(entry->obj) == -1) {
4908 if (ld_tracing == NULL)
4912 if (rc == 0 || ld_tracing != NULL)
4913 rc = rtld_verify_object_versions(&obj_rtld);
4918 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4923 vernum = VER_NDX(obj->versyms[symnum]);
4924 if (vernum >= obj->vernum) {
4925 _rtld_error("%s: symbol %s has wrong verneed value %d",
4926 obj->path, obj->strtab + symnum, vernum);
4927 } else if (obj->vertab[vernum].hash != 0) {
4928 return &obj->vertab[vernum];
4935 _rtld_get_stack_prot(void)
4938 return (stack_prot);
4942 _rtld_is_dlopened(void *arg)
4945 RtldLockState lockstate;
4948 rlock_acquire(rtld_bind_lock, &lockstate);
4951 obj = obj_from_addr(arg);
4953 _rtld_error("No shared object contains address");
4954 lock_release(rtld_bind_lock, &lockstate);
4957 res = obj->dlopened ? 1 : 0;
4958 lock_release(rtld_bind_lock, &lockstate);
4963 map_stacks_exec(RtldLockState *lockstate)
4965 void (*thr_map_stacks_exec)(void);
4967 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4969 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4970 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4971 if (thr_map_stacks_exec != NULL) {
4972 stack_prot |= PROT_EXEC;
4973 thr_map_stacks_exec();
4978 symlook_init(SymLook *dst, const char *name)
4981 bzero(dst, sizeof(*dst));
4983 dst->hash = elf_hash(name);
4984 dst->hash_gnu = gnu_hash(name);
4988 symlook_init_from_req(SymLook *dst, const SymLook *src)
4991 dst->name = src->name;
4992 dst->hash = src->hash;
4993 dst->hash_gnu = src->hash_gnu;
4994 dst->ventry = src->ventry;
4995 dst->flags = src->flags;
4996 dst->defobj_out = NULL;
4997 dst->sym_out = NULL;
4998 dst->lockstate = src->lockstate;
5003 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
5006 parse_libdir(const char *str)
5008 static const int RADIX = 10; /* XXXJA: possibly support hex? */
5015 for (c = *str; c != '\0'; c = *++str) {
5016 if (c < '0' || c > '9')
5023 /* Make sure we actually parsed something. */
5025 _rtld_error("failed to parse directory FD from '%s'", str);
5032 * Overrides for libc_pic-provided functions.
5036 __getosreldate(void)
5046 oid[1] = KERN_OSRELDATE;
5048 len = sizeof(osrel);
5049 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5050 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5062 void (*__cleanup)(void);
5063 int __isthreaded = 0;
5064 int _thread_autoinit_dummy_decl = 1;
5067 * No unresolved symbols for rtld.
5070 __pthread_cxa_finalize(struct dl_phdr_info *a)
5075 __stack_chk_fail(void)
5078 _rtld_error("stack overflow detected; terminated");
5081 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
5087 _rtld_error("buffer overflow detected; terminated");
5092 rtld_strerror(int errnum)
5095 if (errnum < 0 || errnum >= sys_nerr)
5096 return ("Unknown error");
5097 return (sys_errlist[errnum]);