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_elf_hints_default = _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));
326 #ifdef RTLD_VARIANT_ENV_NAMES
328 * construct the env variable based on the type of binary that's
331 static inline const char *
334 static char buffer[128];
336 strlcpy(buffer, ld_env_prefix, sizeof(buffer));
337 strlcat(buffer, var, sizeof(buffer));
345 * Main entry point for dynamic linking. The first argument is the
346 * stack pointer. The stack is expected to be laid out as described
347 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
348 * Specifically, the stack pointer points to a word containing
349 * ARGC. Following that in the stack is a null-terminated sequence
350 * of pointers to argument strings. Then comes a null-terminated
351 * sequence of pointers to environment strings. Finally, there is a
352 * sequence of "auxiliary vector" entries.
354 * The second argument points to a place to store the dynamic linker's
355 * exit procedure pointer and the third to a place to store the main
358 * The return value is the main program's entry point.
361 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
363 Elf_Auxinfo *aux_info[AT_COUNT];
371 Objlist_Entry *entry;
373 Obj_Entry **preload_tail;
374 Obj_Entry *last_interposer;
376 RtldLockState lockstate;
377 char *library_path_rpath;
382 * On entry, the dynamic linker itself has not been relocated yet.
383 * Be very careful not to reference any global data until after
384 * init_rtld has returned. It is OK to reference file-scope statics
385 * and string constants, and to call static and global functions.
388 /* Find the auxiliary vector on the stack. */
391 sp += argc + 1; /* Skip over arguments and NULL terminator */
393 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
395 aux = (Elf_Auxinfo *) sp;
397 /* Digest the auxiliary vector. */
398 for (i = 0; i < AT_COUNT; i++)
400 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
401 if (auxp->a_type < AT_COUNT)
402 aux_info[auxp->a_type] = auxp;
405 /* Initialize and relocate ourselves. */
406 assert(aux_info[AT_BASE] != NULL);
407 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
409 __progname = obj_rtld.path;
410 argv0 = argv[0] != NULL ? argv[0] : "(null)";
415 if (aux_info[AT_CANARY] != NULL &&
416 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
417 i = aux_info[AT_CANARYLEN]->a_un.a_val;
418 if (i > sizeof(__stack_chk_guard))
419 i = sizeof(__stack_chk_guard);
420 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
425 len = sizeof(__stack_chk_guard);
426 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
427 len != sizeof(__stack_chk_guard)) {
428 /* If sysctl was unsuccessful, use the "terminator canary". */
429 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
430 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
431 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
432 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
436 trust = !issetugid();
438 /* md_abi_variant_hook(aux_info); */
440 ld_bind_now = getenv(_LD("BIND_NOW"));
442 * If the process is tainted, then we un-set the dangerous environment
443 * variables. The process will be marked as tainted until setuid(2)
444 * is called. If any child process calls setuid(2) we do not want any
445 * future processes to honor the potentially un-safe variables.
448 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) ||
449 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) ||
450 unsetenv(_LD("LIBMAP_DISABLE")) ||
451 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) ||
452 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) {
453 _rtld_error("environment corrupt; aborting");
457 ld_debug = getenv(_LD("DEBUG"));
458 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL;
459 libmap_override = getenv(_LD("LIBMAP"));
460 ld_library_path = getenv(_LD("LIBRARY_PATH"));
461 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS"));
462 ld_preload = getenv(_LD("PRELOAD"));
463 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH"));
464 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL;
465 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH"));
466 if (library_path_rpath != NULL) {
467 if (library_path_rpath[0] == 'y' ||
468 library_path_rpath[0] == 'Y' ||
469 library_path_rpath[0] == '1')
470 ld_library_path_rpath = true;
472 ld_library_path_rpath = false;
474 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
475 (ld_library_path != NULL) || (ld_preload != NULL) ||
476 (ld_elf_hints_path != NULL) || ld_loadfltr;
477 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS"));
478 ld_utrace = getenv(_LD("UTRACE"));
480 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
481 ld_elf_hints_path = ld_elf_hints_default;
483 if (ld_debug != NULL && *ld_debug != '\0')
485 dbg("%s is initialized, base address = %p", __progname,
486 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
487 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
488 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
490 dbg("initializing thread locks");
494 * Load the main program, or process its program header if it is
497 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
498 int fd = aux_info[AT_EXECFD]->a_un.a_val;
499 dbg("loading main program");
500 obj_main = map_object(fd, argv0, NULL);
502 if (obj_main == NULL)
504 max_stack_flags = obj->stack_flags;
505 } else { /* Main program already loaded. */
506 const Elf_Phdr *phdr;
510 dbg("processing main program's program header");
511 assert(aux_info[AT_PHDR] != NULL);
512 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
513 assert(aux_info[AT_PHNUM] != NULL);
514 phnum = aux_info[AT_PHNUM]->a_un.a_val;
515 assert(aux_info[AT_PHENT] != NULL);
516 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
517 assert(aux_info[AT_ENTRY] != NULL);
518 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
519 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
523 if (aux_info[AT_EXECPATH] != 0) {
525 char buf[MAXPATHLEN];
527 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
528 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
529 if (kexecpath[0] == '/')
530 obj_main->path = kexecpath;
531 else if (getcwd(buf, sizeof(buf)) == NULL ||
532 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
533 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
534 obj_main->path = xstrdup(argv0);
536 obj_main->path = xstrdup(buf);
538 dbg("No AT_EXECPATH");
539 obj_main->path = xstrdup(argv0);
541 dbg("obj_main path %s", obj_main->path);
542 obj_main->mainprog = true;
544 if (aux_info[AT_STACKPROT] != NULL &&
545 aux_info[AT_STACKPROT]->a_un.a_val != 0)
546 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
550 * Get the actual dynamic linker pathname from the executable if
551 * possible. (It should always be possible.) That ensures that
552 * gdb will find the right dynamic linker even if a non-standard
555 if (obj_main->interp != NULL &&
556 strcmp(obj_main->interp, obj_rtld.path) != 0) {
558 obj_rtld.path = xstrdup(obj_main->interp);
559 __progname = obj_rtld.path;
563 digest_dynamic(obj_main, 0);
564 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
565 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
566 obj_main->dynsymcount);
568 linkmap_add(obj_main);
569 linkmap_add(&obj_rtld);
571 /* Link the main program into the list of objects. */
572 *obj_tail = obj_main;
573 obj_tail = &obj_main->next;
577 /* Initialize a fake symbol for resolving undefined weak references. */
578 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
579 sym_zero.st_shndx = SHN_UNDEF;
580 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
583 libmap_disable = (bool)lm_init(libmap_override);
585 dbg("loading LD_PRELOAD libraries");
586 if (load_preload_objects() == -1)
588 preload_tail = obj_tail;
590 dbg("loading needed objects");
591 if (load_needed_objects(obj_main, 0) == -1)
594 /* Make a list of all objects loaded at startup. */
595 last_interposer = obj_main;
596 for (obj = obj_list; obj != NULL; obj = obj->next) {
597 if (obj->z_interpose && obj != obj_main) {
598 objlist_put_after(&list_main, last_interposer, obj);
599 last_interposer = obj;
601 objlist_push_tail(&list_main, obj);
606 dbg("checking for required versions");
607 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
610 if (ld_tracing) { /* We're done */
611 trace_loaded_objects(obj_main);
615 if (getenv(_LD("DUMP_REL_PRE")) != NULL) {
616 dump_relocations(obj_main);
621 * Processing tls relocations requires having the tls offsets
622 * initialized. Prepare offsets before starting initial
623 * relocation processing.
625 dbg("initializing initial thread local storage offsets");
626 STAILQ_FOREACH(entry, &list_main, link) {
628 * Allocate all the initial objects out of the static TLS
629 * block even if they didn't ask for it.
631 allocate_tls_offset(entry->obj);
634 if (relocate_objects(obj_main,
635 ld_bind_now != NULL && *ld_bind_now != '\0',
636 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
639 dbg("doing copy relocations");
640 if (do_copy_relocations(obj_main) == -1)
643 if (getenv(_LD("DUMP_REL_POST")) != NULL) {
644 dump_relocations(obj_main);
649 * Setup TLS for main thread. This must be done after the
650 * relocations are processed, since tls initialization section
651 * might be the subject for relocations.
653 dbg("initializing initial thread local storage");
654 allocate_initial_tls(obj_list);
656 dbg("initializing key program variables");
657 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
658 set_program_var("environ", env);
659 set_program_var("__elf_aux_vector", aux);
661 /* Make a list of init functions to call. */
662 objlist_init(&initlist);
663 initlist_add_objects(obj_list, preload_tail, &initlist);
665 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
667 map_stacks_exec(NULL);
669 dbg("resolving ifuncs");
670 if (resolve_objects_ifunc(obj_main,
671 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
675 if (!obj_main->crt_no_init) {
677 * Make sure we don't call the main program's init and fini
678 * functions for binaries linked with old crt1 which calls
681 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
682 obj_main->preinit_array = obj_main->init_array =
683 obj_main->fini_array = (Elf_Addr)NULL;
686 wlock_acquire(rtld_bind_lock, &lockstate);
687 if (obj_main->crt_no_init)
689 objlist_call_init(&initlist, &lockstate);
690 _r_debug_postinit(&obj_main->linkmap);
691 objlist_clear(&initlist);
692 dbg("loading filtees");
693 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
694 if (ld_loadfltr || obj->z_loadfltr)
695 load_filtees(obj, 0, &lockstate);
697 lock_release(rtld_bind_lock, &lockstate);
699 dbg("transferring control to program entry point = %p", obj_main->entry);
701 /* Return the exit procedure and the program entry point. */
702 *exit_proc = rtld_exit;
704 return (func_ptr_type) obj_main->entry;
708 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
713 ptr = (void *)make_function_pointer(def, obj);
714 target = ((Elf_Addr (*)(void))ptr)();
715 return ((void *)target);
719 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
723 const Obj_Entry *defobj;
726 RtldLockState lockstate;
728 rlock_acquire(rtld_bind_lock, &lockstate);
729 if (sigsetjmp(lockstate.env, 0) != 0)
730 lock_upgrade(rtld_bind_lock, &lockstate);
732 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
734 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
736 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
737 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
741 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
742 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
744 target = (Elf_Addr)(defobj->relocbase + def->st_value);
746 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
747 defobj->strtab + def->st_name, basename(obj->path),
748 (void *)target, basename(defobj->path));
751 * Write the new contents for the jmpslot. Note that depending on
752 * architecture, the value which we need to return back to the
753 * lazy binding trampoline may or may not be the target
754 * address. The value returned from reloc_jmpslot() is the value
755 * that the trampoline needs.
757 target = reloc_jmpslot(where, target, defobj, obj, rel);
758 lock_release(rtld_bind_lock, &lockstate);
763 * Error reporting function. Use it like printf. If formats the message
764 * into a buffer, and sets things up so that the next call to dlerror()
765 * will return the message.
768 _rtld_error(const char *fmt, ...)
770 static char buf[512];
774 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
780 * Return a dynamically-allocated copy of the current error message, if any.
785 return error_message == NULL ? NULL : xstrdup(error_message);
789 * Restore the current error message from a copy which was previously saved
790 * by errmsg_save(). The copy is freed.
793 errmsg_restore(char *saved_msg)
795 if (saved_msg == NULL)
796 error_message = NULL;
798 _rtld_error("%s", saved_msg);
804 basename(const char *name)
806 const char *p = strrchr(name, '/');
807 return p != NULL ? p + 1 : name;
810 static struct utsname uts;
813 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
814 const char *subst, bool may_free)
816 char *p, *p1, *res, *resp;
817 int subst_len, kw_len, subst_count, old_len, new_len;
822 * First, count the number of the keyword occurences, to
823 * preallocate the final string.
825 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
832 * If the keyword is not found, just return.
834 * Return non-substituted string if resolution failed. We
835 * cannot do anything more reasonable, the failure mode of the
836 * caller is unresolved library anyway.
838 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
839 return (may_free ? real : xstrdup(real));
841 subst = obj->origin_path;
844 * There is indeed something to substitute. Calculate the
845 * length of the resulting string, and allocate it.
847 subst_len = strlen(subst);
848 old_len = strlen(real);
849 new_len = old_len + (subst_len - kw_len) * subst_count;
850 res = xmalloc(new_len + 1);
853 * Now, execute the substitution loop.
855 for (p = real, resp = res, *resp = '\0';;) {
858 /* Copy the prefix before keyword. */
859 memcpy(resp, p, p1 - p);
861 /* Keyword replacement. */
862 memcpy(resp, subst, subst_len);
870 /* Copy to the end of string and finish. */
878 origin_subst(Obj_Entry *obj, char *real)
880 char *res1, *res2, *res3, *res4;
882 if (obj == NULL || !trust)
883 return (xstrdup(real));
884 if (uts.sysname[0] == '\0') {
885 if (uname(&uts) != 0) {
886 _rtld_error("utsname failed: %d", errno);
890 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false);
891 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
892 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
893 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
900 const char *msg = dlerror();
904 rtld_fdputstr(STDERR_FILENO, msg);
905 rtld_fdputchar(STDERR_FILENO, '\n');
910 * Process a shared object's DYNAMIC section, and save the important
911 * information in its Obj_Entry structure.
914 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
915 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
918 Needed_Entry **needed_tail = &obj->needed;
919 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
920 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
921 const Elf_Hashelt *hashtab;
922 const Elf32_Word *hashval;
923 Elf32_Word bkt, nmaskwords;
925 int plttype = DT_REL;
931 obj->bind_now = false;
932 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
933 switch (dynp->d_tag) {
936 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
940 obj->relsize = dynp->d_un.d_val;
944 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
948 obj->pltrel = (const Elf_Rel *)
949 (obj->relocbase + dynp->d_un.d_ptr);
953 obj->pltrelsize = dynp->d_un.d_val;
957 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
961 obj->relasize = dynp->d_un.d_val;
965 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
969 plttype = dynp->d_un.d_val;
970 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
974 obj->symtab = (const Elf_Sym *)
975 (obj->relocbase + dynp->d_un.d_ptr);
979 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
983 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
987 obj->strsize = dynp->d_un.d_val;
991 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
996 obj->verneednum = dynp->d_un.d_val;
1000 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
1005 obj->verdefnum = dynp->d_un.d_val;
1009 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1015 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1017 obj->nbuckets = hashtab[0];
1018 obj->nchains = hashtab[1];
1019 obj->buckets = hashtab + 2;
1020 obj->chains = obj->buckets + obj->nbuckets;
1021 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1022 obj->buckets != NULL;
1028 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1030 obj->nbuckets_gnu = hashtab[0];
1031 obj->symndx_gnu = hashtab[1];
1032 nmaskwords = hashtab[2];
1033 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1034 obj->maskwords_bm_gnu = nmaskwords - 1;
1035 obj->shift2_gnu = hashtab[3];
1036 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
1037 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1038 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1040 /* Number of bitmask words is required to be power of 2 */
1041 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1042 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1048 Needed_Entry *nep = NEW(Needed_Entry);
1049 nep->name = dynp->d_un.d_val;
1054 needed_tail = &nep->next;
1060 Needed_Entry *nep = NEW(Needed_Entry);
1061 nep->name = dynp->d_un.d_val;
1065 *needed_filtees_tail = nep;
1066 needed_filtees_tail = &nep->next;
1072 Needed_Entry *nep = NEW(Needed_Entry);
1073 nep->name = dynp->d_un.d_val;
1077 *needed_aux_filtees_tail = nep;
1078 needed_aux_filtees_tail = &nep->next;
1083 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1087 obj->textrel = true;
1091 obj->symbolic = true;
1096 * We have to wait until later to process this, because we
1097 * might not have gotten the address of the string table yet.
1107 *dyn_runpath = dynp;
1111 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1114 case DT_PREINIT_ARRAY:
1115 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1118 case DT_PREINIT_ARRAYSZ:
1119 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1123 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1126 case DT_INIT_ARRAYSZ:
1127 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1131 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1135 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1138 case DT_FINI_ARRAYSZ:
1139 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1143 * Don't process DT_DEBUG on MIPS as the dynamic section
1144 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1148 if (!obj->writable_dynamic)
1151 dbg("Filling in DT_DEBUG entry");
1152 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1156 if (dynp->d_un.d_val & DF_ORIGIN)
1157 obj->z_origin = true;
1158 if (dynp->d_un.d_val & DF_SYMBOLIC)
1159 obj->symbolic = true;
1160 if (dynp->d_un.d_val & DF_TEXTREL)
1161 obj->textrel = true;
1162 if (dynp->d_un.d_val & DF_BIND_NOW)
1163 obj->bind_now = true;
1164 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1168 case DT_MIPS_LOCAL_GOTNO:
1169 obj->local_gotno = dynp->d_un.d_val;
1172 case DT_MIPS_SYMTABNO:
1173 obj->symtabno = dynp->d_un.d_val;
1176 case DT_MIPS_GOTSYM:
1177 obj->gotsym = dynp->d_un.d_val;
1180 case DT_MIPS_RLD_MAP:
1181 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1185 #ifdef __powerpc64__
1186 case DT_PPC64_GLINK:
1187 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1192 if (dynp->d_un.d_val & DF_1_NOOPEN)
1193 obj->z_noopen = true;
1194 if (dynp->d_un.d_val & DF_1_ORIGIN)
1195 obj->z_origin = true;
1196 if (dynp->d_un.d_val & DF_1_GLOBAL)
1197 obj->z_global = true;
1198 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1199 obj->bind_now = true;
1200 if (dynp->d_un.d_val & DF_1_NODELETE)
1201 obj->z_nodelete = true;
1202 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1203 obj->z_loadfltr = true;
1204 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1205 obj->z_interpose = true;
1206 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1207 obj->z_nodeflib = true;
1212 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1219 obj->traced = false;
1221 if (plttype == DT_RELA) {
1222 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1224 obj->pltrelasize = obj->pltrelsize;
1225 obj->pltrelsize = 0;
1228 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1229 if (obj->valid_hash_sysv)
1230 obj->dynsymcount = obj->nchains;
1231 else if (obj->valid_hash_gnu) {
1232 obj->dynsymcount = 0;
1233 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1234 if (obj->buckets_gnu[bkt] == 0)
1236 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1239 while ((*hashval++ & 1u) == 0);
1241 obj->dynsymcount += obj->symndx_gnu;
1246 obj_resolve_origin(Obj_Entry *obj)
1249 if (obj->origin_path != NULL)
1251 obj->origin_path = xmalloc(PATH_MAX);
1252 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1256 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1257 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1260 if (obj->z_origin && !obj_resolve_origin(obj))
1263 if (dyn_runpath != NULL) {
1264 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1265 obj->runpath = origin_subst(obj, obj->runpath);
1266 } else if (dyn_rpath != NULL) {
1267 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1268 obj->rpath = origin_subst(obj, obj->rpath);
1270 if (dyn_soname != NULL)
1271 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1275 digest_dynamic(Obj_Entry *obj, int early)
1277 const Elf_Dyn *dyn_rpath;
1278 const Elf_Dyn *dyn_soname;
1279 const Elf_Dyn *dyn_runpath;
1281 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1282 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1286 * Process a shared object's program header. This is used only for the
1287 * main program, when the kernel has already loaded the main program
1288 * into memory before calling the dynamic linker. It creates and
1289 * returns an Obj_Entry structure.
1292 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1295 const Elf_Phdr *phlimit = phdr + phnum;
1297 Elf_Addr note_start, note_end;
1301 for (ph = phdr; ph < phlimit; ph++) {
1302 if (ph->p_type != PT_PHDR)
1306 obj->phsize = ph->p_memsz;
1307 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1311 obj->stack_flags = PF_X | PF_R | PF_W;
1313 for (ph = phdr; ph < phlimit; ph++) {
1314 switch (ph->p_type) {
1317 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1321 if (nsegs == 0) { /* First load segment */
1322 obj->vaddrbase = trunc_page(ph->p_vaddr);
1323 obj->mapbase = obj->vaddrbase + obj->relocbase;
1324 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1326 } else { /* Last load segment */
1327 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1334 if (ph->p_flags & PROT_WRITE)
1335 obj->writable_dynamic = true;
1336 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1341 obj->tlssize = ph->p_memsz;
1342 obj->tlsalign = ph->p_align;
1343 obj->tlsinitsize = ph->p_filesz;
1344 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1348 obj->stack_flags = ph->p_flags;
1352 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1353 obj->relro_size = round_page(ph->p_memsz);
1357 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1358 note_end = note_start + ph->p_filesz;
1359 digest_notes(obj, note_start, note_end);
1364 _rtld_error("%s: too few PT_LOAD segments", path);
1373 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1375 const Elf_Note *note;
1376 const char *note_name;
1379 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1380 note = (const Elf_Note *)((const char *)(note + 1) +
1381 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1382 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1383 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1384 note->n_descsz != sizeof(int32_t))
1386 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1387 note->n_type != NT_FREEBSD_NOINIT_TAG)
1389 note_name = (const char *)(note + 1);
1390 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1391 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1393 switch (note->n_type) {
1394 case NT_FREEBSD_ABI_TAG:
1395 /* FreeBSD osrel note */
1396 p = (uintptr_t)(note + 1);
1397 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1398 obj->osrel = *(const int32_t *)(p);
1399 dbg("note osrel %d", obj->osrel);
1401 case NT_FREEBSD_NOINIT_TAG:
1402 /* FreeBSD 'crt does not call init' note */
1403 obj->crt_no_init = true;
1404 dbg("note crt_no_init");
1411 dlcheck(void *handle)
1415 for (obj = obj_list; obj != NULL; obj = obj->next)
1416 if (obj == (Obj_Entry *) handle)
1419 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1420 _rtld_error("Invalid shared object handle %p", handle);
1427 * If the given object is already in the donelist, return true. Otherwise
1428 * add the object to the list and return false.
1431 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1435 for (i = 0; i < dlp->num_used; i++)
1436 if (dlp->objs[i] == obj)
1439 * Our donelist allocation should always be sufficient. But if
1440 * our threads locking isn't working properly, more shared objects
1441 * could have been loaded since we allocated the list. That should
1442 * never happen, but we'll handle it properly just in case it does.
1444 if (dlp->num_used < dlp->num_alloc)
1445 dlp->objs[dlp->num_used++] = obj;
1450 * Hash function for symbol table lookup. Don't even think about changing
1451 * this. It is specified by the System V ABI.
1454 elf_hash(const char *name)
1456 const unsigned char *p = (const unsigned char *) name;
1457 unsigned long h = 0;
1460 while (*p != '\0') {
1461 h = (h << 4) + *p++;
1462 if ((g = h & 0xf0000000) != 0)
1470 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1471 * unsigned in case it's implemented with a wider type.
1474 gnu_hash(const char *s)
1480 for (c = *s; c != '\0'; c = *++s)
1482 return (h & 0xffffffff);
1487 * Find the library with the given name, and return its full pathname.
1488 * The returned string is dynamically allocated. Generates an error
1489 * message and returns NULL if the library cannot be found.
1491 * If the second argument is non-NULL, then it refers to an already-
1492 * loaded shared object, whose library search path will be searched.
1494 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1495 * descriptor (which is close-on-exec) will be passed out via the third
1498 * The search order is:
1499 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1500 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1502 * DT_RUNPATH in the referencing file
1503 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1505 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1507 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1510 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1514 bool nodeflib, objgiven;
1516 objgiven = refobj != NULL;
1517 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1518 if (xname[0] != '/' && !trust) {
1519 _rtld_error("Absolute pathname required for shared object \"%s\"",
1523 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1524 __DECONST(char *, xname)));
1527 if (libmap_disable || !objgiven ||
1528 (name = lm_find(refobj->path, xname)) == NULL)
1529 name = (char *)xname;
1531 dbg(" Searching for \"%s\"", name);
1534 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1535 * back to pre-conforming behaviour if user requested so with
1536 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1539 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1540 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1542 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1543 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL ||
1544 (pathname = search_library_path(name, gethints(false))) != NULL ||
1545 (pathname = search_library_path(name, ld_standard_library_path)) != NULL)
1548 nodeflib = objgiven ? refobj->z_nodeflib : false;
1550 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1551 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1552 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1553 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1555 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1556 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL ||
1557 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1558 (objgiven && !nodeflib &&
1559 (pathname = search_library_path(name, ld_standard_library_path)) != NULL))
1563 if (objgiven && refobj->path != NULL) {
1564 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1565 name, basename(refobj->path));
1567 _rtld_error("Shared object \"%s\" not found", name);
1573 * Given a symbol number in a referencing object, find the corresponding
1574 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1575 * no definition was found. Returns a pointer to the Obj_Entry of the
1576 * defining object via the reference parameter DEFOBJ_OUT.
1579 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1580 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1581 RtldLockState *lockstate)
1585 const Obj_Entry *defobj;
1591 * If we have already found this symbol, get the information from
1594 if (symnum >= refobj->dynsymcount)
1595 return NULL; /* Bad object */
1596 if (cache != NULL && cache[symnum].sym != NULL) {
1597 *defobj_out = cache[symnum].obj;
1598 return cache[symnum].sym;
1601 ref = refobj->symtab + symnum;
1602 name = refobj->strtab + ref->st_name;
1607 * We don't have to do a full scale lookup if the symbol is local.
1608 * We know it will bind to the instance in this load module; to
1609 * which we already have a pointer (ie ref). By not doing a lookup,
1610 * we not only improve performance, but it also avoids unresolvable
1611 * symbols when local symbols are not in the hash table. This has
1612 * been seen with the ia64 toolchain.
1614 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1615 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1616 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1619 symlook_init(&req, name);
1621 req.ventry = fetch_ventry(refobj, symnum);
1622 req.lockstate = lockstate;
1623 res = symlook_default(&req, refobj);
1626 defobj = req.defobj_out;
1634 * If we found no definition and the reference is weak, treat the
1635 * symbol as having the value zero.
1637 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1643 *defobj_out = defobj;
1644 /* Record the information in the cache to avoid subsequent lookups. */
1645 if (cache != NULL) {
1646 cache[symnum].sym = def;
1647 cache[symnum].obj = defobj;
1650 if (refobj != &obj_rtld)
1651 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1657 * Return the search path from the ldconfig hints file, reading it if
1658 * necessary. If nostdlib is true, then the default search paths are
1659 * not added to result.
1661 * Returns NULL if there are problems with the hints file,
1662 * or if the search path there is empty.
1665 gethints(bool nostdlib)
1667 static char *hints, *filtered_path;
1668 struct elfhints_hdr hdr;
1669 struct fill_search_info_args sargs, hargs;
1670 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1671 struct dl_serpath *SLPpath, *hintpath;
1673 unsigned int SLPndx, hintndx, fndx, fcount;
1678 /* First call, read the hints file */
1679 if (hints == NULL) {
1680 /* Keep from trying again in case the hints file is bad. */
1683 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1685 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1686 hdr.magic != ELFHINTS_MAGIC ||
1691 p = xmalloc(hdr.dirlistlen + 1);
1692 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1693 read(fd, p, hdr.dirlistlen + 1) !=
1694 (ssize_t)hdr.dirlistlen + 1) {
1704 * If caller agreed to receive list which includes the default
1705 * paths, we are done. Otherwise, if we still did not
1706 * calculated filtered result, do it now.
1709 return (hints[0] != '\0' ? hints : NULL);
1710 if (filtered_path != NULL)
1714 * Obtain the list of all configured search paths, and the
1715 * list of the default paths.
1717 * First estimate the size of the results.
1719 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1721 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1724 sargs.request = RTLD_DI_SERINFOSIZE;
1725 sargs.serinfo = &smeta;
1726 hargs.request = RTLD_DI_SERINFOSIZE;
1727 hargs.serinfo = &hmeta;
1729 path_enumerate(ld_standard_library_path, fill_search_info, &sargs);
1730 path_enumerate(p, fill_search_info, &hargs);
1732 SLPinfo = xmalloc(smeta.dls_size);
1733 hintinfo = xmalloc(hmeta.dls_size);
1736 * Next fetch both sets of paths.
1738 sargs.request = RTLD_DI_SERINFO;
1739 sargs.serinfo = SLPinfo;
1740 sargs.serpath = &SLPinfo->dls_serpath[0];
1741 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1743 hargs.request = RTLD_DI_SERINFO;
1744 hargs.serinfo = hintinfo;
1745 hargs.serpath = &hintinfo->dls_serpath[0];
1746 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1748 path_enumerate(ld_standard_library_path, fill_search_info, &sargs);
1749 path_enumerate(p, fill_search_info, &hargs);
1752 * Now calculate the difference between two sets, by excluding
1753 * standard paths from the full set.
1757 filtered_path = xmalloc(hdr.dirlistlen + 1);
1758 hintpath = &hintinfo->dls_serpath[0];
1759 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1761 SLPpath = &SLPinfo->dls_serpath[0];
1763 * Check each standard path against current.
1765 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1766 /* matched, skip the path */
1767 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1775 * Not matched against any standard path, add the path
1776 * to result. Separate consequtive paths with ':'.
1779 filtered_path[fndx] = ':';
1783 flen = strlen(hintpath->dls_name);
1784 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1787 filtered_path[fndx] = '\0';
1793 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1797 init_dag(Obj_Entry *root)
1799 const Needed_Entry *needed;
1800 const Objlist_Entry *elm;
1803 if (root->dag_inited)
1805 donelist_init(&donelist);
1807 /* Root object belongs to own DAG. */
1808 objlist_push_tail(&root->dldags, root);
1809 objlist_push_tail(&root->dagmembers, root);
1810 donelist_check(&donelist, root);
1813 * Add dependencies of root object to DAG in breadth order
1814 * by exploiting the fact that each new object get added
1815 * to the tail of the dagmembers list.
1817 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1818 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1819 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1821 objlist_push_tail(&needed->obj->dldags, root);
1822 objlist_push_tail(&root->dagmembers, needed->obj);
1825 root->dag_inited = true;
1829 process_z(Obj_Entry *root)
1831 const Objlist_Entry *elm;
1835 * Walk over object DAG and process every dependent object
1836 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
1837 * to grow their own DAG.
1839 * For DF_1_GLOBAL, DAG is required for symbol lookups in
1840 * symlook_global() to work.
1842 * For DF_1_NODELETE, the DAG should have its reference upped.
1844 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1848 if (obj->z_nodelete && !obj->ref_nodel) {
1849 dbg("obj %s -z nodelete", obj->path);
1852 obj->ref_nodel = true;
1854 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
1855 dbg("obj %s -z global", obj->path);
1856 objlist_push_tail(&list_global, obj);
1862 * Initialize the dynamic linker. The argument is the address at which
1863 * the dynamic linker has been mapped into memory. The primary task of
1864 * this function is to relocate the dynamic linker.
1867 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1869 Obj_Entry objtmp; /* Temporary rtld object */
1870 const Elf_Dyn *dyn_rpath;
1871 const Elf_Dyn *dyn_soname;
1872 const Elf_Dyn *dyn_runpath;
1874 #ifdef RTLD_INIT_PAGESIZES_EARLY
1875 /* The page size is required by the dynamic memory allocator. */
1876 init_pagesizes(aux_info);
1880 * Conjure up an Obj_Entry structure for the dynamic linker.
1882 * The "path" member can't be initialized yet because string constants
1883 * cannot yet be accessed. Below we will set it correctly.
1885 memset(&objtmp, 0, sizeof(objtmp));
1888 objtmp.mapbase = mapbase;
1890 objtmp.relocbase = mapbase;
1892 if (RTLD_IS_DYNAMIC()) {
1893 objtmp.dynamic = rtld_dynamic(&objtmp);
1894 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1895 assert(objtmp.needed == NULL);
1896 #if !defined(__mips__)
1897 /* MIPS has a bogus DT_TEXTREL. */
1898 assert(!objtmp.textrel);
1902 * Temporarily put the dynamic linker entry into the object list, so
1903 * that symbols can be found.
1906 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1909 /* Initialize the object list. */
1910 obj_tail = &obj_list;
1912 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1913 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1915 #ifndef RTLD_INIT_PAGESIZES_EARLY
1916 /* The page size is required by the dynamic memory allocator. */
1917 init_pagesizes(aux_info);
1920 if (aux_info[AT_OSRELDATE] != NULL)
1921 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1923 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1925 /* Replace the path with a dynamically allocated copy. */
1926 obj_rtld.path = xstrdup(ld_path_rtld);
1928 r_debug.r_brk = r_debug_state;
1929 r_debug.r_state = RT_CONSISTENT;
1933 * Retrieve the array of supported page sizes. The kernel provides the page
1934 * sizes in increasing order.
1937 init_pagesizes(Elf_Auxinfo **aux_info)
1939 static size_t psa[MAXPAGESIZES];
1943 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
1945 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
1946 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
1949 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
1952 /* As a fallback, retrieve the base page size. */
1953 size = sizeof(psa[0]);
1954 if (aux_info[AT_PAGESZ] != NULL) {
1955 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
1959 mib[1] = HW_PAGESIZE;
1963 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
1964 _rtld_error("sysctl for hw.pagesize(s) failed");
1970 npagesizes = size / sizeof(pagesizes[0]);
1971 /* Discard any invalid entries at the end of the array. */
1972 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
1977 * Add the init functions from a needed object list (and its recursive
1978 * needed objects) to "list". This is not used directly; it is a helper
1979 * function for initlist_add_objects(). The write lock must be held
1980 * when this function is called.
1983 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1985 /* Recursively process the successor needed objects. */
1986 if (needed->next != NULL)
1987 initlist_add_neededs(needed->next, list);
1989 /* Process the current needed object. */
1990 if (needed->obj != NULL)
1991 initlist_add_objects(needed->obj, &needed->obj->next, list);
1995 * Scan all of the DAGs rooted in the range of objects from "obj" to
1996 * "tail" and add their init functions to "list". This recurses over
1997 * the DAGs and ensure the proper init ordering such that each object's
1998 * needed libraries are initialized before the object itself. At the
1999 * same time, this function adds the objects to the global finalization
2000 * list "list_fini" in the opposite order. The write lock must be
2001 * held when this function is called.
2004 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
2007 if (obj->init_scanned || obj->init_done)
2009 obj->init_scanned = true;
2011 /* Recursively process the successor objects. */
2012 if (&obj->next != tail)
2013 initlist_add_objects(obj->next, tail, list);
2015 /* Recursively process the needed objects. */
2016 if (obj->needed != NULL)
2017 initlist_add_neededs(obj->needed, list);
2018 if (obj->needed_filtees != NULL)
2019 initlist_add_neededs(obj->needed_filtees, list);
2020 if (obj->needed_aux_filtees != NULL)
2021 initlist_add_neededs(obj->needed_aux_filtees, list);
2023 /* Add the object to the init list. */
2024 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
2025 obj->init_array != (Elf_Addr)NULL)
2026 objlist_push_tail(list, obj);
2028 /* Add the object to the global fini list in the reverse order. */
2029 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2030 && !obj->on_fini_list) {
2031 objlist_push_head(&list_fini, obj);
2032 obj->on_fini_list = true;
2037 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2041 free_needed_filtees(Needed_Entry *n)
2043 Needed_Entry *needed, *needed1;
2045 for (needed = n; needed != NULL; needed = needed->next) {
2046 if (needed->obj != NULL) {
2047 dlclose(needed->obj);
2051 for (needed = n; needed != NULL; needed = needed1) {
2052 needed1 = needed->next;
2058 unload_filtees(Obj_Entry *obj)
2061 free_needed_filtees(obj->needed_filtees);
2062 obj->needed_filtees = NULL;
2063 free_needed_filtees(obj->needed_aux_filtees);
2064 obj->needed_aux_filtees = NULL;
2065 obj->filtees_loaded = false;
2069 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2070 RtldLockState *lockstate)
2073 for (; needed != NULL; needed = needed->next) {
2074 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2075 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2076 RTLD_LOCAL, lockstate);
2081 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2084 lock_restart_for_upgrade(lockstate);
2085 if (!obj->filtees_loaded) {
2086 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2087 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2088 obj->filtees_loaded = true;
2093 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2097 for (; needed != NULL; needed = needed->next) {
2098 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2099 flags & ~RTLD_LO_NOLOAD);
2100 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2107 * Given a shared object, traverse its list of needed objects, and load
2108 * each of them. Returns 0 on success. Generates an error message and
2109 * returns -1 on failure.
2112 load_needed_objects(Obj_Entry *first, int flags)
2116 for (obj = first; obj != NULL; obj = obj->next) {
2117 if (process_needed(obj, obj->needed, flags) == -1)
2124 load_preload_objects(void)
2126 char *p = ld_preload;
2128 static const char delim[] = " \t:;";
2133 p += strspn(p, delim);
2134 while (*p != '\0') {
2135 size_t len = strcspn(p, delim);
2140 obj = load_object(p, -1, NULL, 0);
2142 return -1; /* XXX - cleanup */
2143 obj->z_interpose = true;
2146 p += strspn(p, delim);
2148 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2153 printable_path(const char *path)
2156 return (path == NULL ? "<unknown>" : path);
2160 * Load a shared object into memory, if it is not already loaded. The
2161 * object may be specified by name or by user-supplied file descriptor
2162 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2165 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2169 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2178 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2179 if (object_match_name(obj, name))
2183 path = find_library(name, refobj, &fd);
2191 * search_library_pathfds() opens a fresh file descriptor for the
2192 * library, so there is no need to dup().
2194 } else if (fd_u == -1) {
2196 * If we didn't find a match by pathname, or the name is not
2197 * supplied, open the file and check again by device and inode.
2198 * This avoids false mismatches caused by multiple links or ".."
2201 * To avoid a race, we open the file and use fstat() rather than
2204 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2205 _rtld_error("Cannot open \"%s\"", path);
2210 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2212 _rtld_error("Cannot dup fd");
2217 if (fstat(fd, &sb) == -1) {
2218 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2223 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2224 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2226 if (obj != NULL && name != NULL) {
2227 object_add_name(obj, name);
2232 if (flags & RTLD_LO_NOLOAD) {
2238 /* First use of this object, so we must map it in */
2239 obj = do_load_object(fd, name, path, &sb, flags);
2248 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2255 * but first, make sure that environment variables haven't been
2256 * used to circumvent the noexec flag on a filesystem.
2258 if (dangerous_ld_env) {
2259 if (fstatfs(fd, &fs) != 0) {
2260 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2263 if (fs.f_flags & MNT_NOEXEC) {
2264 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2268 dbg("loading \"%s\"", printable_path(path));
2269 obj = map_object(fd, printable_path(path), sbp);
2274 * If DT_SONAME is present in the object, digest_dynamic2 already
2275 * added it to the object names.
2278 object_add_name(obj, name);
2280 digest_dynamic(obj, 0);
2281 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2282 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2283 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2285 dbg("refusing to load non-loadable \"%s\"", obj->path);
2286 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2287 munmap(obj->mapbase, obj->mapsize);
2292 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2294 obj_tail = &obj->next;
2297 linkmap_add(obj); /* for GDB & dlinfo() */
2298 max_stack_flags |= obj->stack_flags;
2300 dbg(" %p .. %p: %s", obj->mapbase,
2301 obj->mapbase + obj->mapsize - 1, obj->path);
2303 dbg(" WARNING: %s has impure text", obj->path);
2304 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2311 obj_from_addr(const void *addr)
2315 for (obj = obj_list; obj != NULL; obj = obj->next) {
2316 if (addr < (void *) obj->mapbase)
2318 if (addr < (void *) (obj->mapbase + obj->mapsize))
2327 Elf_Addr *preinit_addr;
2330 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2331 if (preinit_addr == NULL)
2334 for (index = 0; index < obj_main->preinit_array_num; index++) {
2335 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2336 dbg("calling preinit function for %s at %p", obj_main->path,
2337 (void *)preinit_addr[index]);
2338 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2339 0, 0, obj_main->path);
2340 call_init_pointer(obj_main, preinit_addr[index]);
2346 * Call the finalization functions for each of the objects in "list"
2347 * belonging to the DAG of "root" and referenced once. If NULL "root"
2348 * is specified, every finalization function will be called regardless
2349 * of the reference count and the list elements won't be freed. All of
2350 * the objects are expected to have non-NULL fini functions.
2353 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2357 Elf_Addr *fini_addr;
2360 assert(root == NULL || root->refcount == 1);
2363 * Preserve the current error message since a fini function might
2364 * call into the dynamic linker and overwrite it.
2366 saved_msg = errmsg_save();
2368 STAILQ_FOREACH(elm, list, link) {
2369 if (root != NULL && (elm->obj->refcount != 1 ||
2370 objlist_find(&root->dagmembers, elm->obj) == NULL))
2372 /* Remove object from fini list to prevent recursive invocation. */
2373 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2375 * XXX: If a dlopen() call references an object while the
2376 * fini function is in progress, we might end up trying to
2377 * unload the referenced object in dlclose() or the object
2378 * won't be unloaded although its fini function has been
2381 lock_release(rtld_bind_lock, lockstate);
2384 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2385 * When this happens, DT_FINI_ARRAY is processed first.
2387 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2388 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2389 for (index = elm->obj->fini_array_num - 1; index >= 0;
2391 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2392 dbg("calling fini function for %s at %p",
2393 elm->obj->path, (void *)fini_addr[index]);
2394 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2395 (void *)fini_addr[index], 0, 0, elm->obj->path);
2396 call_initfini_pointer(elm->obj, fini_addr[index]);
2400 if (elm->obj->fini != (Elf_Addr)NULL) {
2401 dbg("calling fini function for %s at %p", elm->obj->path,
2402 (void *)elm->obj->fini);
2403 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2404 0, 0, elm->obj->path);
2405 call_initfini_pointer(elm->obj, elm->obj->fini);
2407 wlock_acquire(rtld_bind_lock, lockstate);
2408 /* No need to free anything if process is going down. */
2412 * We must restart the list traversal after every fini call
2413 * because a dlclose() call from the fini function or from
2414 * another thread might have modified the reference counts.
2418 } while (elm != NULL);
2419 errmsg_restore(saved_msg);
2423 * Call the initialization functions for each of the objects in
2424 * "list". All of the objects are expected to have non-NULL init
2428 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2433 Elf_Addr *init_addr;
2437 * Clean init_scanned flag so that objects can be rechecked and
2438 * possibly initialized earlier if any of vectors called below
2439 * cause the change by using dlopen.
2441 for (obj = obj_list; obj != NULL; obj = obj->next)
2442 obj->init_scanned = false;
2445 * Preserve the current error message since an init function might
2446 * call into the dynamic linker and overwrite it.
2448 saved_msg = errmsg_save();
2449 STAILQ_FOREACH(elm, list, link) {
2450 if (elm->obj->init_done) /* Initialized early. */
2453 * Race: other thread might try to use this object before current
2454 * one completes the initilization. Not much can be done here
2455 * without better locking.
2457 elm->obj->init_done = true;
2458 lock_release(rtld_bind_lock, lockstate);
2461 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2462 * When this happens, DT_INIT is processed first.
2464 if (elm->obj->init != (Elf_Addr)NULL) {
2465 dbg("calling init function for %s at %p", elm->obj->path,
2466 (void *)elm->obj->init);
2467 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2468 0, 0, elm->obj->path);
2469 call_initfini_pointer(elm->obj, elm->obj->init);
2471 init_addr = (Elf_Addr *)elm->obj->init_array;
2472 if (init_addr != NULL) {
2473 for (index = 0; index < elm->obj->init_array_num; index++) {
2474 if (init_addr[index] != 0 && init_addr[index] != 1) {
2475 dbg("calling init function for %s at %p", elm->obj->path,
2476 (void *)init_addr[index]);
2477 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2478 (void *)init_addr[index], 0, 0, elm->obj->path);
2479 call_init_pointer(elm->obj, init_addr[index]);
2483 wlock_acquire(rtld_bind_lock, lockstate);
2485 errmsg_restore(saved_msg);
2489 objlist_clear(Objlist *list)
2493 while (!STAILQ_EMPTY(list)) {
2494 elm = STAILQ_FIRST(list);
2495 STAILQ_REMOVE_HEAD(list, link);
2500 static Objlist_Entry *
2501 objlist_find(Objlist *list, const Obj_Entry *obj)
2505 STAILQ_FOREACH(elm, list, link)
2506 if (elm->obj == obj)
2512 objlist_init(Objlist *list)
2518 objlist_push_head(Objlist *list, Obj_Entry *obj)
2522 elm = NEW(Objlist_Entry);
2524 STAILQ_INSERT_HEAD(list, elm, link);
2528 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2532 elm = NEW(Objlist_Entry);
2534 STAILQ_INSERT_TAIL(list, elm, link);
2538 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2540 Objlist_Entry *elm, *listelm;
2542 STAILQ_FOREACH(listelm, list, link) {
2543 if (listelm->obj == listobj)
2546 elm = NEW(Objlist_Entry);
2548 if (listelm != NULL)
2549 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2551 STAILQ_INSERT_TAIL(list, elm, link);
2555 objlist_remove(Objlist *list, Obj_Entry *obj)
2559 if ((elm = objlist_find(list, obj)) != NULL) {
2560 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2566 * Relocate dag rooted in the specified object.
2567 * Returns 0 on success, or -1 on failure.
2571 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2572 int flags, RtldLockState *lockstate)
2578 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2579 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2588 * Relocate single object.
2589 * Returns 0 on success, or -1 on failure.
2592 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2593 int flags, RtldLockState *lockstate)
2598 obj->relocated = true;
2600 dbg("relocating \"%s\"", obj->path);
2602 if (obj->symtab == NULL || obj->strtab == NULL ||
2603 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2604 _rtld_error("%s: Shared object has no run-time symbol table",
2610 /* There are relocations to the write-protected text segment. */
2611 if (mprotect(obj->mapbase, obj->textsize,
2612 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2613 _rtld_error("%s: Cannot write-enable text segment: %s",
2614 obj->path, rtld_strerror(errno));
2619 /* Process the non-PLT non-IFUNC relocations. */
2620 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2623 if (obj->textrel) { /* Re-protected the text segment. */
2624 if (mprotect(obj->mapbase, obj->textsize,
2625 PROT_READ|PROT_EXEC) == -1) {
2626 _rtld_error("%s: Cannot write-protect text segment: %s",
2627 obj->path, rtld_strerror(errno));
2632 /* Set the special PLT or GOT entries. */
2635 /* Process the PLT relocations. */
2636 if (reloc_plt(obj) == -1)
2638 /* Relocate the jump slots if we are doing immediate binding. */
2639 if (obj->bind_now || bind_now)
2640 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2644 * Process the non-PLT IFUNC relocations. The relocations are
2645 * processed in two phases, because IFUNC resolvers may
2646 * reference other symbols, which must be readily processed
2647 * before resolvers are called.
2649 if (obj->non_plt_gnu_ifunc &&
2650 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
2653 if (obj->relro_size > 0) {
2654 if (mprotect(obj->relro_page, obj->relro_size,
2656 _rtld_error("%s: Cannot enforce relro protection: %s",
2657 obj->path, rtld_strerror(errno));
2663 * Set up the magic number and version in the Obj_Entry. These
2664 * were checked in the crt1.o from the original ElfKit, so we
2665 * set them for backward compatibility.
2667 obj->magic = RTLD_MAGIC;
2668 obj->version = RTLD_VERSION;
2674 * Relocate newly-loaded shared objects. The argument is a pointer to
2675 * the Obj_Entry for the first such object. All objects from the first
2676 * to the end of the list of objects are relocated. Returns 0 on success,
2680 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2681 int flags, RtldLockState *lockstate)
2686 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2687 error = relocate_object(obj, bind_now, rtldobj, flags,
2696 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2697 * referencing STT_GNU_IFUNC symbols is postponed till the other
2698 * relocations are done. The indirect functions specified as
2699 * ifunc are allowed to call other symbols, so we need to have
2700 * objects relocated before asking for resolution from indirects.
2702 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2703 * instead of the usual lazy handling of PLT slots. It is
2704 * consistent with how GNU does it.
2707 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2708 RtldLockState *lockstate)
2710 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2712 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2713 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2719 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2720 RtldLockState *lockstate)
2724 for (obj = first; obj != NULL; obj = obj->next) {
2725 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2732 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2733 RtldLockState *lockstate)
2737 STAILQ_FOREACH(elm, list, link) {
2738 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2746 * Cleanup procedure. It will be called (by the atexit mechanism) just
2747 * before the process exits.
2752 RtldLockState lockstate;
2754 wlock_acquire(rtld_bind_lock, &lockstate);
2756 objlist_call_fini(&list_fini, NULL, &lockstate);
2757 /* No need to remove the items from the list, since we are exiting. */
2758 if (!libmap_disable)
2760 lock_release(rtld_bind_lock, &lockstate);
2764 * Iterate over a search path, translate each element, and invoke the
2765 * callback on the result.
2768 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2774 path += strspn(path, ":;");
2775 while (*path != '\0') {
2779 len = strcspn(path, ":;");
2780 trans = lm_findn(NULL, path, len);
2782 res = callback(trans, strlen(trans), arg);
2784 res = callback(path, len, arg);
2790 path += strspn(path, ":;");
2796 struct try_library_args {
2804 try_library_path(const char *dir, size_t dirlen, void *param)
2806 struct try_library_args *arg;
2809 if (*dir == '/' || trust) {
2812 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2815 pathname = arg->buffer;
2816 strncpy(pathname, dir, dirlen);
2817 pathname[dirlen] = '/';
2818 strcpy(pathname + dirlen + 1, arg->name);
2820 dbg(" Trying \"%s\"", pathname);
2821 if (access(pathname, F_OK) == 0) { /* We found it */
2822 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2823 strcpy(pathname, arg->buffer);
2831 search_library_path(const char *name, const char *path)
2834 struct try_library_args arg;
2840 arg.namelen = strlen(name);
2841 arg.buffer = xmalloc(PATH_MAX);
2842 arg.buflen = PATH_MAX;
2844 p = path_enumerate(path, try_library_path, &arg);
2853 * Finds the library with the given name using the directory descriptors
2854 * listed in the LD_LIBRARY_PATH_FDS environment variable.
2856 * Returns a freshly-opened close-on-exec file descriptor for the library,
2857 * or -1 if the library cannot be found.
2860 search_library_pathfds(const char *name, const char *path, int *fdp)
2862 char *envcopy, *fdstr, *found, *last_token;
2866 dbg("%s('%s', '%s', fdp)", __func__, name, path);
2868 /* Don't load from user-specified libdirs into setuid binaries. */
2872 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
2876 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
2877 if (name[0] == '/') {
2878 dbg("Absolute path (%s) passed to %s", name, __func__);
2883 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
2884 * copy of the path, as strtok_r rewrites separator tokens
2888 envcopy = xstrdup(path);
2889 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
2890 fdstr = strtok_r(NULL, ":", &last_token)) {
2891 dirfd = parse_libdir(fdstr);
2894 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
2897 len = strlen(fdstr) + strlen(name) + 3;
2898 found = xmalloc(len);
2899 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
2900 _rtld_error("error generating '%d/%s'",
2904 dbg("open('%s') => %d", found, fd);
2915 dlclose(void *handle)
2918 RtldLockState lockstate;
2920 wlock_acquire(rtld_bind_lock, &lockstate);
2921 root = dlcheck(handle);
2923 lock_release(rtld_bind_lock, &lockstate);
2926 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2929 /* Unreference the object and its dependencies. */
2930 root->dl_refcount--;
2932 if (root->refcount == 1) {
2934 * The object will be no longer referenced, so we must unload it.
2935 * First, call the fini functions.
2937 objlist_call_fini(&list_fini, root, &lockstate);
2941 /* Finish cleaning up the newly-unreferenced objects. */
2942 GDB_STATE(RT_DELETE,&root->linkmap);
2943 unload_object(root);
2944 GDB_STATE(RT_CONSISTENT,NULL);
2948 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2949 lock_release(rtld_bind_lock, &lockstate);
2956 char *msg = error_message;
2957 error_message = NULL;
2962 * This function is deprecated and has no effect.
2965 dllockinit(void *context,
2966 void *(*lock_create)(void *context),
2967 void (*rlock_acquire)(void *lock),
2968 void (*wlock_acquire)(void *lock),
2969 void (*lock_release)(void *lock),
2970 void (*lock_destroy)(void *lock),
2971 void (*context_destroy)(void *context))
2973 static void *cur_context;
2974 static void (*cur_context_destroy)(void *);
2976 /* Just destroy the context from the previous call, if necessary. */
2977 if (cur_context_destroy != NULL)
2978 cur_context_destroy(cur_context);
2979 cur_context = context;
2980 cur_context_destroy = context_destroy;
2984 dlopen(const char *name, int mode)
2987 return (rtld_dlopen(name, -1, mode));
2991 fdlopen(int fd, int mode)
2994 return (rtld_dlopen(NULL, fd, mode));
2998 rtld_dlopen(const char *name, int fd, int mode)
3000 RtldLockState lockstate;
3003 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3004 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3005 if (ld_tracing != NULL) {
3006 rlock_acquire(rtld_bind_lock, &lockstate);
3007 if (sigsetjmp(lockstate.env, 0) != 0)
3008 lock_upgrade(rtld_bind_lock, &lockstate);
3009 environ = (char **)*get_program_var_addr("environ", &lockstate);
3010 lock_release(rtld_bind_lock, &lockstate);
3012 lo_flags = RTLD_LO_DLOPEN;
3013 if (mode & RTLD_NODELETE)
3014 lo_flags |= RTLD_LO_NODELETE;
3015 if (mode & RTLD_NOLOAD)
3016 lo_flags |= RTLD_LO_NOLOAD;
3017 if (ld_tracing != NULL)
3018 lo_flags |= RTLD_LO_TRACE;
3020 return (dlopen_object(name, fd, obj_main, lo_flags,
3021 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3025 dlopen_cleanup(Obj_Entry *obj)
3030 if (obj->refcount == 0)
3035 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3036 int mode, RtldLockState *lockstate)
3038 Obj_Entry **old_obj_tail;
3041 RtldLockState mlockstate;
3044 objlist_init(&initlist);
3046 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3047 wlock_acquire(rtld_bind_lock, &mlockstate);
3048 lockstate = &mlockstate;
3050 GDB_STATE(RT_ADD,NULL);
3052 old_obj_tail = obj_tail;
3054 if (name == NULL && fd == -1) {
3058 obj = load_object(name, fd, refobj, lo_flags);
3063 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3064 objlist_push_tail(&list_global, obj);
3065 if (*old_obj_tail != NULL) { /* We loaded something new. */
3066 assert(*old_obj_tail == obj);
3067 result = load_needed_objects(obj,
3068 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
3072 result = rtld_verify_versions(&obj->dagmembers);
3073 if (result != -1 && ld_tracing)
3075 if (result == -1 || relocate_object_dag(obj,
3076 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3077 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3079 dlopen_cleanup(obj);
3081 } else if (lo_flags & RTLD_LO_EARLY) {
3083 * Do not call the init functions for early loaded
3084 * filtees. The image is still not initialized enough
3087 * Our object is found by the global object list and
3088 * will be ordered among all init calls done right
3089 * before transferring control to main.
3092 /* Make list of init functions to call. */
3093 initlist_add_objects(obj, &obj->next, &initlist);
3096 * Process all no_delete or global objects here, given
3097 * them own DAGs to prevent their dependencies from being
3098 * unloaded. This has to be done after we have loaded all
3099 * of the dependencies, so that we do not miss any.
3105 * Bump the reference counts for objects on this DAG. If
3106 * this is the first dlopen() call for the object that was
3107 * already loaded as a dependency, initialize the dag
3113 if ((lo_flags & RTLD_LO_TRACE) != 0)
3116 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3117 obj->z_nodelete) && !obj->ref_nodel) {
3118 dbg("obj %s nodelete", obj->path);
3120 obj->z_nodelete = obj->ref_nodel = true;
3124 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3126 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3128 if (!(lo_flags & RTLD_LO_EARLY)) {
3129 map_stacks_exec(lockstate);
3132 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3133 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3135 objlist_clear(&initlist);
3136 dlopen_cleanup(obj);
3137 if (lockstate == &mlockstate)
3138 lock_release(rtld_bind_lock, lockstate);
3142 if (!(lo_flags & RTLD_LO_EARLY)) {
3143 /* Call the init functions. */
3144 objlist_call_init(&initlist, lockstate);
3146 objlist_clear(&initlist);
3147 if (lockstate == &mlockstate)
3148 lock_release(rtld_bind_lock, lockstate);
3151 trace_loaded_objects(obj);
3152 if (lockstate == &mlockstate)
3153 lock_release(rtld_bind_lock, lockstate);
3158 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3162 const Obj_Entry *obj, *defobj;
3165 RtldLockState lockstate;
3172 symlook_init(&req, name);
3174 req.flags = flags | SYMLOOK_IN_PLT;
3175 req.lockstate = &lockstate;
3177 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3178 rlock_acquire(rtld_bind_lock, &lockstate);
3179 if (sigsetjmp(lockstate.env, 0) != 0)
3180 lock_upgrade(rtld_bind_lock, &lockstate);
3181 if (handle == NULL || handle == RTLD_NEXT ||
3182 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3184 if ((obj = obj_from_addr(retaddr)) == NULL) {
3185 _rtld_error("Cannot determine caller's shared object");
3186 lock_release(rtld_bind_lock, &lockstate);
3187 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3190 if (handle == NULL) { /* Just the caller's shared object. */
3191 res = symlook_obj(&req, obj);
3194 defobj = req.defobj_out;
3196 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3197 handle == RTLD_SELF) { /* ... caller included */
3198 if (handle == RTLD_NEXT)
3200 for (; obj != NULL; obj = obj->next) {
3201 res = symlook_obj(&req, obj);
3204 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3206 defobj = req.defobj_out;
3207 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3213 * Search the dynamic linker itself, and possibly resolve the
3214 * symbol from there. This is how the application links to
3215 * dynamic linker services such as dlopen.
3217 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3218 res = symlook_obj(&req, &obj_rtld);
3221 defobj = req.defobj_out;
3225 assert(handle == RTLD_DEFAULT);
3226 res = symlook_default(&req, obj);
3228 defobj = req.defobj_out;
3233 if ((obj = dlcheck(handle)) == NULL) {
3234 lock_release(rtld_bind_lock, &lockstate);
3235 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3239 donelist_init(&donelist);
3240 if (obj->mainprog) {
3241 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3242 res = symlook_global(&req, &donelist);
3245 defobj = req.defobj_out;
3248 * Search the dynamic linker itself, and possibly resolve the
3249 * symbol from there. This is how the application links to
3250 * dynamic linker services such as dlopen.
3252 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3253 res = symlook_obj(&req, &obj_rtld);
3256 defobj = req.defobj_out;
3261 /* Search the whole DAG rooted at the given object. */
3262 res = symlook_list(&req, &obj->dagmembers, &donelist);
3265 defobj = req.defobj_out;
3271 lock_release(rtld_bind_lock, &lockstate);
3274 * The value required by the caller is derived from the value
3275 * of the symbol. this is simply the relocated value of the
3278 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3279 sym = make_function_pointer(def, defobj);
3280 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3281 sym = rtld_resolve_ifunc(defobj, def);
3282 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3283 ti.ti_module = defobj->tlsindex;
3284 ti.ti_offset = def->st_value;
3285 sym = __tls_get_addr(&ti);
3287 sym = defobj->relocbase + def->st_value;
3288 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3292 _rtld_error("Undefined symbol \"%s\"", name);
3293 lock_release(rtld_bind_lock, &lockstate);
3294 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3299 dlsym(void *handle, const char *name)
3301 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3306 dlfunc(void *handle, const char *name)
3313 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3319 dlvsym(void *handle, const char *name, const char *version)
3323 ventry.name = version;
3325 ventry.hash = elf_hash(version);
3327 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3332 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3334 const Obj_Entry *obj;
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 rtld_fill_dl_phdr_info(obj, phdr_info);
3345 lock_release(rtld_bind_lock, &lockstate);
3350 dladdr(const void *addr, Dl_info *info)
3352 const Obj_Entry *obj;
3355 unsigned long symoffset;
3356 RtldLockState lockstate;
3358 rlock_acquire(rtld_bind_lock, &lockstate);
3359 obj = obj_from_addr(addr);
3361 _rtld_error("No shared object contains address");
3362 lock_release(rtld_bind_lock, &lockstate);
3365 info->dli_fname = obj->path;
3366 info->dli_fbase = obj->mapbase;
3367 info->dli_saddr = (void *)0;
3368 info->dli_sname = NULL;
3371 * Walk the symbol list looking for the symbol whose address is
3372 * closest to the address sent in.
3374 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3375 def = obj->symtab + symoffset;
3378 * For skip the symbol if st_shndx is either SHN_UNDEF or
3381 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3385 * If the symbol is greater than the specified address, or if it
3386 * is further away from addr than the current nearest symbol,
3389 symbol_addr = obj->relocbase + def->st_value;
3390 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3393 /* Update our idea of the nearest symbol. */
3394 info->dli_sname = obj->strtab + def->st_name;
3395 info->dli_saddr = symbol_addr;
3398 if (info->dli_saddr == addr)
3401 lock_release(rtld_bind_lock, &lockstate);
3406 dlinfo(void *handle, int request, void *p)
3408 const Obj_Entry *obj;
3409 RtldLockState lockstate;
3412 rlock_acquire(rtld_bind_lock, &lockstate);
3414 if (handle == NULL || handle == RTLD_SELF) {
3417 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3418 if ((obj = obj_from_addr(retaddr)) == NULL)
3419 _rtld_error("Cannot determine caller's shared object");
3421 obj = dlcheck(handle);
3424 lock_release(rtld_bind_lock, &lockstate);
3430 case RTLD_DI_LINKMAP:
3431 *((struct link_map const **)p) = &obj->linkmap;
3433 case RTLD_DI_ORIGIN:
3434 error = rtld_dirname(obj->path, p);
3437 case RTLD_DI_SERINFOSIZE:
3438 case RTLD_DI_SERINFO:
3439 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3443 _rtld_error("Invalid request %d passed to dlinfo()", request);
3447 lock_release(rtld_bind_lock, &lockstate);
3453 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3456 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3457 phdr_info->dlpi_name = obj->path;
3458 phdr_info->dlpi_phdr = obj->phdr;
3459 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3460 phdr_info->dlpi_tls_modid = obj->tlsindex;
3461 phdr_info->dlpi_tls_data = obj->tlsinit;
3462 phdr_info->dlpi_adds = obj_loads;
3463 phdr_info->dlpi_subs = obj_loads - obj_count;
3467 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3469 struct dl_phdr_info phdr_info;
3470 const Obj_Entry *obj;
3471 RtldLockState bind_lockstate, phdr_lockstate;
3474 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3475 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3479 for (obj = obj_list; obj != NULL; obj = obj->next) {
3480 rtld_fill_dl_phdr_info(obj, &phdr_info);
3481 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3486 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3487 error = callback(&phdr_info, sizeof(phdr_info), param);
3490 lock_release(rtld_bind_lock, &bind_lockstate);
3491 lock_release(rtld_phdr_lock, &phdr_lockstate);
3497 fill_search_info(const char *dir, size_t dirlen, void *param)
3499 struct fill_search_info_args *arg;
3503 if (arg->request == RTLD_DI_SERINFOSIZE) {
3504 arg->serinfo->dls_cnt ++;
3505 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3507 struct dl_serpath *s_entry;
3509 s_entry = arg->serpath;
3510 s_entry->dls_name = arg->strspace;
3511 s_entry->dls_flags = arg->flags;
3513 strncpy(arg->strspace, dir, dirlen);
3514 arg->strspace[dirlen] = '\0';
3516 arg->strspace += dirlen + 1;
3524 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3526 struct dl_serinfo _info;
3527 struct fill_search_info_args args;
3529 args.request = RTLD_DI_SERINFOSIZE;
3530 args.serinfo = &_info;
3532 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3535 path_enumerate(obj->rpath, fill_search_info, &args);
3536 path_enumerate(ld_library_path, fill_search_info, &args);
3537 path_enumerate(obj->runpath, fill_search_info, &args);
3538 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3539 if (!obj->z_nodeflib)
3540 path_enumerate(ld_standard_library_path, fill_search_info, &args);
3543 if (request == RTLD_DI_SERINFOSIZE) {
3544 info->dls_size = _info.dls_size;
3545 info->dls_cnt = _info.dls_cnt;
3549 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3550 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3554 args.request = RTLD_DI_SERINFO;
3555 args.serinfo = info;
3556 args.serpath = &info->dls_serpath[0];
3557 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3559 args.flags = LA_SER_RUNPATH;
3560 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3563 args.flags = LA_SER_LIBPATH;
3564 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3567 args.flags = LA_SER_RUNPATH;
3568 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3571 args.flags = LA_SER_CONFIG;
3572 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3576 args.flags = LA_SER_DEFAULT;
3577 if (!obj->z_nodeflib &&
3578 path_enumerate(ld_standard_library_path, fill_search_info, &args) != NULL)
3584 rtld_dirname(const char *path, char *bname)
3588 /* Empty or NULL string gets treated as "." */
3589 if (path == NULL || *path == '\0') {
3595 /* Strip trailing slashes */
3596 endp = path + strlen(path) - 1;
3597 while (endp > path && *endp == '/')
3600 /* Find the start of the dir */
3601 while (endp > path && *endp != '/')
3604 /* Either the dir is "/" or there are no slashes */
3606 bname[0] = *endp == '/' ? '/' : '.';
3612 } while (endp > path && *endp == '/');
3615 if (endp - path + 2 > PATH_MAX)
3617 _rtld_error("Filename is too long: %s", path);
3621 strncpy(bname, path, endp - path + 1);
3622 bname[endp - path + 1] = '\0';
3627 rtld_dirname_abs(const char *path, char *base)
3631 if (realpath(path, base) == NULL)
3633 dbg("%s -> %s", path, base);
3634 last = strrchr(base, '/');
3643 linkmap_add(Obj_Entry *obj)
3645 struct link_map *l = &obj->linkmap;
3646 struct link_map *prev;
3648 obj->linkmap.l_name = obj->path;
3649 obj->linkmap.l_addr = obj->mapbase;
3650 obj->linkmap.l_ld = obj->dynamic;
3652 /* GDB needs load offset on MIPS to use the symbols */
3653 obj->linkmap.l_offs = obj->relocbase;
3656 if (r_debug.r_map == NULL) {
3662 * Scan to the end of the list, but not past the entry for the
3663 * dynamic linker, which we want to keep at the very end.
3665 for (prev = r_debug.r_map;
3666 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3667 prev = prev->l_next)
3670 /* Link in the new entry. */
3672 l->l_next = prev->l_next;
3673 if (l->l_next != NULL)
3674 l->l_next->l_prev = l;
3679 linkmap_delete(Obj_Entry *obj)
3681 struct link_map *l = &obj->linkmap;
3683 if (l->l_prev == NULL) {
3684 if ((r_debug.r_map = l->l_next) != NULL)
3685 l->l_next->l_prev = NULL;
3689 if ((l->l_prev->l_next = l->l_next) != NULL)
3690 l->l_next->l_prev = l->l_prev;
3694 * Function for the debugger to set a breakpoint on to gain control.
3696 * The two parameters allow the debugger to easily find and determine
3697 * what the runtime loader is doing and to whom it is doing it.
3699 * When the loadhook trap is hit (r_debug_state, set at program
3700 * initialization), the arguments can be found on the stack:
3702 * +8 struct link_map *m
3703 * +4 struct r_debug *rd
3707 r_debug_state(struct r_debug* rd, struct link_map *m)
3710 * The following is a hack to force the compiler to emit calls to
3711 * this function, even when optimizing. If the function is empty,
3712 * the compiler is not obliged to emit any code for calls to it,
3713 * even when marked __noinline. However, gdb depends on those
3716 __compiler_membar();
3720 * A function called after init routines have completed. This can be used to
3721 * break before a program's entry routine is called, and can be used when
3722 * main is not available in the symbol table.
3725 _r_debug_postinit(struct link_map *m)
3728 /* See r_debug_state(). */
3729 __compiler_membar();
3733 * Get address of the pointer variable in the main program.
3734 * Prefer non-weak symbol over the weak one.
3736 static const void **
3737 get_program_var_addr(const char *name, RtldLockState *lockstate)
3742 symlook_init(&req, name);
3743 req.lockstate = lockstate;
3744 donelist_init(&donelist);
3745 if (symlook_global(&req, &donelist) != 0)
3747 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3748 return ((const void **)make_function_pointer(req.sym_out,
3750 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3751 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3753 return ((const void **)(req.defobj_out->relocbase +
3754 req.sym_out->st_value));
3758 * Set a pointer variable in the main program to the given value. This
3759 * is used to set key variables such as "environ" before any of the
3760 * init functions are called.
3763 set_program_var(const char *name, const void *value)
3767 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3768 dbg("\"%s\": *%p <-- %p", name, addr, value);
3774 * Search the global objects, including dependencies and main object,
3775 * for the given symbol.
3778 symlook_global(SymLook *req, DoneList *donelist)
3781 const Objlist_Entry *elm;
3784 symlook_init_from_req(&req1, req);
3786 /* Search all objects loaded at program start up. */
3787 if (req->defobj_out == NULL ||
3788 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3789 res = symlook_list(&req1, &list_main, donelist);
3790 if (res == 0 && (req->defobj_out == NULL ||
3791 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3792 req->sym_out = req1.sym_out;
3793 req->defobj_out = req1.defobj_out;
3794 assert(req->defobj_out != NULL);
3798 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3799 STAILQ_FOREACH(elm, &list_global, link) {
3800 if (req->defobj_out != NULL &&
3801 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3803 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3804 if (res == 0 && (req->defobj_out == NULL ||
3805 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3806 req->sym_out = req1.sym_out;
3807 req->defobj_out = req1.defobj_out;
3808 assert(req->defobj_out != NULL);
3812 return (req->sym_out != NULL ? 0 : ESRCH);
3816 * Given a symbol name in a referencing object, find the corresponding
3817 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3818 * no definition was found. Returns a pointer to the Obj_Entry of the
3819 * defining object via the reference parameter DEFOBJ_OUT.
3822 symlook_default(SymLook *req, const Obj_Entry *refobj)
3825 const Objlist_Entry *elm;
3829 donelist_init(&donelist);
3830 symlook_init_from_req(&req1, req);
3832 /* Look first in the referencing object if linked symbolically. */
3833 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3834 res = symlook_obj(&req1, refobj);
3836 req->sym_out = req1.sym_out;
3837 req->defobj_out = req1.defobj_out;
3838 assert(req->defobj_out != NULL);
3842 symlook_global(req, &donelist);
3844 /* Search all dlopened DAGs containing the referencing object. */
3845 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3846 if (req->sym_out != NULL &&
3847 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3849 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3850 if (res == 0 && (req->sym_out == NULL ||
3851 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3852 req->sym_out = req1.sym_out;
3853 req->defobj_out = req1.defobj_out;
3854 assert(req->defobj_out != NULL);
3859 * Search the dynamic linker itself, and possibly resolve the
3860 * symbol from there. This is how the application links to
3861 * dynamic linker services such as dlopen.
3863 if (req->sym_out == NULL ||
3864 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3865 res = symlook_obj(&req1, &obj_rtld);
3867 req->sym_out = req1.sym_out;
3868 req->defobj_out = req1.defobj_out;
3869 assert(req->defobj_out != NULL);
3873 return (req->sym_out != NULL ? 0 : ESRCH);
3877 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3880 const Obj_Entry *defobj;
3881 const Objlist_Entry *elm;
3887 STAILQ_FOREACH(elm, objlist, link) {
3888 if (donelist_check(dlp, elm->obj))
3890 symlook_init_from_req(&req1, req);
3891 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3892 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3894 defobj = req1.defobj_out;
3895 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3902 req->defobj_out = defobj;
3909 * Search the chain of DAGS cointed to by the given Needed_Entry
3910 * for a symbol of the given name. Each DAG is scanned completely
3911 * before advancing to the next one. Returns a pointer to the symbol,
3912 * or NULL if no definition was found.
3915 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3918 const Needed_Entry *n;
3919 const Obj_Entry *defobj;
3925 symlook_init_from_req(&req1, req);
3926 for (n = needed; n != NULL; n = n->next) {
3927 if (n->obj == NULL ||
3928 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3930 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3932 defobj = req1.defobj_out;
3933 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3939 req->defobj_out = defobj;
3946 * Search the symbol table of a single shared object for a symbol of
3947 * the given name and version, if requested. Returns a pointer to the
3948 * symbol, or NULL if no definition was found. If the object is
3949 * filter, return filtered symbol from filtee.
3951 * The symbol's hash value is passed in for efficiency reasons; that
3952 * eliminates many recomputations of the hash value.
3955 symlook_obj(SymLook *req, const Obj_Entry *obj)
3959 int flags, res, mres;
3962 * If there is at least one valid hash at this point, we prefer to
3963 * use the faster GNU version if available.
3965 if (obj->valid_hash_gnu)
3966 mres = symlook_obj1_gnu(req, obj);
3967 else if (obj->valid_hash_sysv)
3968 mres = symlook_obj1_sysv(req, obj);
3973 if (obj->needed_filtees != NULL) {
3974 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3975 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3976 donelist_init(&donelist);
3977 symlook_init_from_req(&req1, req);
3978 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3980 req->sym_out = req1.sym_out;
3981 req->defobj_out = req1.defobj_out;
3985 if (obj->needed_aux_filtees != NULL) {
3986 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3987 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3988 donelist_init(&donelist);
3989 symlook_init_from_req(&req1, req);
3990 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3992 req->sym_out = req1.sym_out;
3993 req->defobj_out = req1.defobj_out;
4001 /* Symbol match routine common to both hash functions */
4003 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4004 const unsigned long symnum)
4007 const Elf_Sym *symp;
4010 symp = obj->symtab + symnum;
4011 strp = obj->strtab + symp->st_name;
4013 switch (ELF_ST_TYPE(symp->st_info)) {
4019 if (symp->st_value == 0)
4023 if (symp->st_shndx != SHN_UNDEF)
4026 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4027 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4034 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4037 if (req->ventry == NULL) {
4038 if (obj->versyms != NULL) {
4039 verndx = VER_NDX(obj->versyms[symnum]);
4040 if (verndx > obj->vernum) {
4042 "%s: symbol %s references wrong version %d",
4043 obj->path, obj->strtab + symnum, verndx);
4047 * If we are not called from dlsym (i.e. this
4048 * is a normal relocation from unversioned
4049 * binary), accept the symbol immediately if
4050 * it happens to have first version after this
4051 * shared object became versioned. Otherwise,
4052 * if symbol is versioned and not hidden,
4053 * remember it. If it is the only symbol with
4054 * this name exported by the shared object, it
4055 * will be returned as a match by the calling
4056 * function. If symbol is global (verndx < 2)
4057 * accept it unconditionally.
4059 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4060 verndx == VER_NDX_GIVEN) {
4061 result->sym_out = symp;
4064 else if (verndx >= VER_NDX_GIVEN) {
4065 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4067 if (result->vsymp == NULL)
4068 result->vsymp = symp;
4074 result->sym_out = symp;
4077 if (obj->versyms == NULL) {
4078 if (object_match_name(obj, req->ventry->name)) {
4079 _rtld_error("%s: object %s should provide version %s "
4080 "for symbol %s", obj_rtld.path, obj->path,
4081 req->ventry->name, obj->strtab + symnum);
4085 verndx = VER_NDX(obj->versyms[symnum]);
4086 if (verndx > obj->vernum) {
4087 _rtld_error("%s: symbol %s references wrong version %d",
4088 obj->path, obj->strtab + symnum, verndx);
4091 if (obj->vertab[verndx].hash != req->ventry->hash ||
4092 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4094 * Version does not match. Look if this is a
4095 * global symbol and if it is not hidden. If
4096 * global symbol (verndx < 2) is available,
4097 * use it. Do not return symbol if we are
4098 * called by dlvsym, because dlvsym looks for
4099 * a specific version and default one is not
4100 * what dlvsym wants.
4102 if ((req->flags & SYMLOOK_DLSYM) ||
4103 (verndx >= VER_NDX_GIVEN) ||
4104 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4108 result->sym_out = symp;
4113 * Search for symbol using SysV hash function.
4114 * obj->buckets is known not to be NULL at this point; the test for this was
4115 * performed with the obj->valid_hash_sysv assignment.
4118 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4120 unsigned long symnum;
4121 Sym_Match_Result matchres;
4123 matchres.sym_out = NULL;
4124 matchres.vsymp = NULL;
4125 matchres.vcount = 0;
4127 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4128 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4129 if (symnum >= obj->nchains)
4130 return (ESRCH); /* Bad object */
4132 if (matched_symbol(req, obj, &matchres, symnum)) {
4133 req->sym_out = matchres.sym_out;
4134 req->defobj_out = obj;
4138 if (matchres.vcount == 1) {
4139 req->sym_out = matchres.vsymp;
4140 req->defobj_out = obj;
4146 /* Search for symbol using GNU hash function */
4148 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4150 Elf_Addr bloom_word;
4151 const Elf32_Word *hashval;
4153 Sym_Match_Result matchres;
4154 unsigned int h1, h2;
4155 unsigned long symnum;
4157 matchres.sym_out = NULL;
4158 matchres.vsymp = NULL;
4159 matchres.vcount = 0;
4161 /* Pick right bitmask word from Bloom filter array */
4162 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4163 obj->maskwords_bm_gnu];
4165 /* Calculate modulus word size of gnu hash and its derivative */
4166 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4167 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4169 /* Filter out the "definitely not in set" queries */
4170 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4173 /* Locate hash chain and corresponding value element*/
4174 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4177 hashval = &obj->chain_zero_gnu[bucket];
4179 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4180 symnum = hashval - obj->chain_zero_gnu;
4181 if (matched_symbol(req, obj, &matchres, symnum)) {
4182 req->sym_out = matchres.sym_out;
4183 req->defobj_out = obj;
4187 } while ((*hashval++ & 1) == 0);
4188 if (matchres.vcount == 1) {
4189 req->sym_out = matchres.vsymp;
4190 req->defobj_out = obj;
4197 trace_loaded_objects(Obj_Entry *obj)
4199 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4202 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL)
4205 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL)
4206 fmt1 = "\t%o => %p (%x)\n";
4208 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL)
4209 fmt2 = "\t%o (%x)\n";
4211 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL"));
4213 for (; obj; obj = obj->next) {
4214 Needed_Entry *needed;
4218 if (list_containers && obj->needed != NULL)
4219 rtld_printf("%s:\n", obj->path);
4220 for (needed = obj->needed; needed; needed = needed->next) {
4221 if (needed->obj != NULL) {
4222 if (needed->obj->traced && !list_containers)
4224 needed->obj->traced = true;
4225 path = needed->obj->path;
4229 name = (char *)obj->strtab + needed->name;
4230 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4232 fmt = is_lib ? fmt1 : fmt2;
4233 while ((c = *fmt++) != '\0') {
4259 rtld_putstr(main_local);
4262 rtld_putstr(obj_main->path);
4269 rtld_printf("%d", sodp->sod_major);
4272 rtld_printf("%d", sodp->sod_minor);
4279 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4292 * Unload a dlopened object and its dependencies from memory and from
4293 * our data structures. It is assumed that the DAG rooted in the
4294 * object has already been unreferenced, and that the object has a
4295 * reference count of 0.
4298 unload_object(Obj_Entry *root)
4303 assert(root->refcount == 0);
4306 * Pass over the DAG removing unreferenced objects from
4307 * appropriate lists.
4309 unlink_object(root);
4311 /* Unmap all objects that are no longer referenced. */
4312 linkp = &obj_list->next;
4313 while ((obj = *linkp) != NULL) {
4314 if (obj->refcount == 0) {
4315 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4317 dbg("unloading \"%s\"", obj->path);
4318 unload_filtees(root);
4319 munmap(obj->mapbase, obj->mapsize);
4320 linkmap_delete(obj);
4331 unlink_object(Obj_Entry *root)
4335 if (root->refcount == 0) {
4336 /* Remove the object from the RTLD_GLOBAL list. */
4337 objlist_remove(&list_global, root);
4339 /* Remove the object from all objects' DAG lists. */
4340 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4341 objlist_remove(&elm->obj->dldags, root);
4342 if (elm->obj != root)
4343 unlink_object(elm->obj);
4349 ref_dag(Obj_Entry *root)
4353 assert(root->dag_inited);
4354 STAILQ_FOREACH(elm, &root->dagmembers, link)
4355 elm->obj->refcount++;
4359 unref_dag(Obj_Entry *root)
4363 assert(root->dag_inited);
4364 STAILQ_FOREACH(elm, &root->dagmembers, link)
4365 elm->obj->refcount--;
4369 * Common code for MD __tls_get_addr().
4371 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4373 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4375 Elf_Addr *newdtv, *dtv;
4376 RtldLockState lockstate;
4380 /* Check dtv generation in case new modules have arrived */
4381 if (dtv[0] != tls_dtv_generation) {
4382 wlock_acquire(rtld_bind_lock, &lockstate);
4383 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4385 if (to_copy > tls_max_index)
4386 to_copy = tls_max_index;
4387 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4388 newdtv[0] = tls_dtv_generation;
4389 newdtv[1] = tls_max_index;
4391 lock_release(rtld_bind_lock, &lockstate);
4392 dtv = *dtvp = newdtv;
4395 /* Dynamically allocate module TLS if necessary */
4396 if (dtv[index + 1] == 0) {
4397 /* Signal safe, wlock will block out signals. */
4398 wlock_acquire(rtld_bind_lock, &lockstate);
4399 if (!dtv[index + 1])
4400 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4401 lock_release(rtld_bind_lock, &lockstate);
4403 return ((void *)(dtv[index + 1] + offset));
4407 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4412 /* Check dtv generation in case new modules have arrived */
4413 if (__predict_true(dtv[0] == tls_dtv_generation &&
4414 dtv[index + 1] != 0))
4415 return ((void *)(dtv[index + 1] + offset));
4416 return (tls_get_addr_slow(dtvp, index, offset));
4419 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
4420 defined(__powerpc__) || defined(__riscv__)
4423 * Allocate Static TLS using the Variant I method.
4426 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4435 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4438 assert(tcbsize >= TLS_TCB_SIZE);
4439 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4440 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4442 if (oldtcb != NULL) {
4443 memcpy(tls, oldtcb, tls_static_space);
4446 /* Adjust the DTV. */
4448 for (i = 0; i < dtv[1]; i++) {
4449 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4450 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4451 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4455 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4457 dtv[0] = tls_dtv_generation;
4458 dtv[1] = tls_max_index;
4460 for (obj = objs; obj; obj = obj->next) {
4461 if (obj->tlsoffset > 0) {
4462 addr = (Elf_Addr)tls + obj->tlsoffset;
4463 if (obj->tlsinitsize > 0)
4464 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4465 if (obj->tlssize > obj->tlsinitsize)
4466 memset((void*) (addr + obj->tlsinitsize), 0,
4467 obj->tlssize - obj->tlsinitsize);
4468 dtv[obj->tlsindex + 1] = addr;
4477 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4480 Elf_Addr tlsstart, tlsend;
4483 assert(tcbsize >= TLS_TCB_SIZE);
4485 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4486 tlsend = tlsstart + tls_static_space;
4488 dtv = *(Elf_Addr **)tlsstart;
4490 for (i = 0; i < dtvsize; i++) {
4491 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4492 free((void*)dtv[i+2]);
4501 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4504 * Allocate Static TLS using the Variant II method.
4507 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4510 size_t size, ralign;
4512 Elf_Addr *dtv, *olddtv;
4513 Elf_Addr segbase, oldsegbase, addr;
4517 if (tls_static_max_align > ralign)
4518 ralign = tls_static_max_align;
4519 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4521 assert(tcbsize >= 2*sizeof(Elf_Addr));
4522 tls = malloc_aligned(size, ralign);
4523 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4525 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4526 ((Elf_Addr*)segbase)[0] = segbase;
4527 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4529 dtv[0] = tls_dtv_generation;
4530 dtv[1] = tls_max_index;
4534 * Copy the static TLS block over whole.
4536 oldsegbase = (Elf_Addr) oldtls;
4537 memcpy((void *)(segbase - tls_static_space),
4538 (const void *)(oldsegbase - tls_static_space),
4542 * If any dynamic TLS blocks have been created tls_get_addr(),
4545 olddtv = ((Elf_Addr**)oldsegbase)[1];
4546 for (i = 0; i < olddtv[1]; i++) {
4547 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4548 dtv[i+2] = olddtv[i+2];
4554 * We assume that this block was the one we created with
4555 * allocate_initial_tls().
4557 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4559 for (obj = objs; obj; obj = obj->next) {
4560 if (obj->tlsoffset) {
4561 addr = segbase - obj->tlsoffset;
4562 memset((void*) (addr + obj->tlsinitsize),
4563 0, obj->tlssize - obj->tlsinitsize);
4565 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4566 dtv[obj->tlsindex + 1] = addr;
4571 return (void*) segbase;
4575 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4578 size_t size, ralign;
4580 Elf_Addr tlsstart, tlsend;
4583 * Figure out the size of the initial TLS block so that we can
4584 * find stuff which ___tls_get_addr() allocated dynamically.
4587 if (tls_static_max_align > ralign)
4588 ralign = tls_static_max_align;
4589 size = round(tls_static_space, ralign);
4591 dtv = ((Elf_Addr**)tls)[1];
4593 tlsend = (Elf_Addr) tls;
4594 tlsstart = tlsend - size;
4595 for (i = 0; i < dtvsize; i++) {
4596 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4597 free_aligned((void *)dtv[i + 2]);
4601 free_aligned((void *)tlsstart);
4608 * Allocate TLS block for module with given index.
4611 allocate_module_tls(int index)
4616 for (obj = obj_list; obj; obj = obj->next) {
4617 if (obj->tlsindex == index)
4621 _rtld_error("Can't find module with TLS index %d", index);
4625 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4626 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4627 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4633 allocate_tls_offset(Obj_Entry *obj)
4640 if (obj->tlssize == 0) {
4641 obj->tls_done = true;
4645 if (tls_last_offset == 0)
4646 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4648 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4649 obj->tlssize, obj->tlsalign);
4652 * If we have already fixed the size of the static TLS block, we
4653 * must stay within that size. When allocating the static TLS, we
4654 * leave a small amount of space spare to be used for dynamically
4655 * loading modules which use static TLS.
4657 if (tls_static_space != 0) {
4658 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4660 } else if (obj->tlsalign > tls_static_max_align) {
4661 tls_static_max_align = obj->tlsalign;
4664 tls_last_offset = obj->tlsoffset = off;
4665 tls_last_size = obj->tlssize;
4666 obj->tls_done = true;
4672 free_tls_offset(Obj_Entry *obj)
4676 * If we were the last thing to allocate out of the static TLS
4677 * block, we give our space back to the 'allocator'. This is a
4678 * simplistic workaround to allow libGL.so.1 to be loaded and
4679 * unloaded multiple times.
4681 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4682 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4683 tls_last_offset -= obj->tlssize;
4689 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4692 RtldLockState lockstate;
4694 wlock_acquire(rtld_bind_lock, &lockstate);
4695 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4696 lock_release(rtld_bind_lock, &lockstate);
4701 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4703 RtldLockState lockstate;
4705 wlock_acquire(rtld_bind_lock, &lockstate);
4706 free_tls(tcb, tcbsize, tcbalign);
4707 lock_release(rtld_bind_lock, &lockstate);
4711 object_add_name(Obj_Entry *obj, const char *name)
4717 entry = malloc(sizeof(Name_Entry) + len);
4719 if (entry != NULL) {
4720 strcpy(entry->name, name);
4721 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4726 object_match_name(const Obj_Entry *obj, const char *name)
4730 STAILQ_FOREACH(entry, &obj->names, link) {
4731 if (strcmp(name, entry->name) == 0)
4738 locate_dependency(const Obj_Entry *obj, const char *name)
4740 const Objlist_Entry *entry;
4741 const Needed_Entry *needed;
4743 STAILQ_FOREACH(entry, &list_main, link) {
4744 if (object_match_name(entry->obj, name))
4748 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4749 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4750 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4752 * If there is DT_NEEDED for the name we are looking for,
4753 * we are all set. Note that object might not be found if
4754 * dependency was not loaded yet, so the function can
4755 * return NULL here. This is expected and handled
4756 * properly by the caller.
4758 return (needed->obj);
4761 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4767 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4768 const Elf_Vernaux *vna)
4770 const Elf_Verdef *vd;
4771 const char *vername;
4773 vername = refobj->strtab + vna->vna_name;
4774 vd = depobj->verdef;
4776 _rtld_error("%s: version %s required by %s not defined",
4777 depobj->path, vername, refobj->path);
4781 if (vd->vd_version != VER_DEF_CURRENT) {
4782 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4783 depobj->path, vd->vd_version);
4786 if (vna->vna_hash == vd->vd_hash) {
4787 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4788 ((char *)vd + vd->vd_aux);
4789 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4792 if (vd->vd_next == 0)
4794 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4796 if (vna->vna_flags & VER_FLG_WEAK)
4798 _rtld_error("%s: version %s required by %s not found",
4799 depobj->path, vername, refobj->path);
4804 rtld_verify_object_versions(Obj_Entry *obj)
4806 const Elf_Verneed *vn;
4807 const Elf_Verdef *vd;
4808 const Elf_Verdaux *vda;
4809 const Elf_Vernaux *vna;
4810 const Obj_Entry *depobj;
4811 int maxvernum, vernum;
4813 if (obj->ver_checked)
4815 obj->ver_checked = true;
4819 * Walk over defined and required version records and figure out
4820 * max index used by any of them. Do very basic sanity checking
4824 while (vn != NULL) {
4825 if (vn->vn_version != VER_NEED_CURRENT) {
4826 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4827 obj->path, vn->vn_version);
4830 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4832 vernum = VER_NEED_IDX(vna->vna_other);
4833 if (vernum > maxvernum)
4835 if (vna->vna_next == 0)
4837 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4839 if (vn->vn_next == 0)
4841 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4845 while (vd != NULL) {
4846 if (vd->vd_version != VER_DEF_CURRENT) {
4847 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4848 obj->path, vd->vd_version);
4851 vernum = VER_DEF_IDX(vd->vd_ndx);
4852 if (vernum > maxvernum)
4854 if (vd->vd_next == 0)
4856 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4863 * Store version information in array indexable by version index.
4864 * Verify that object version requirements are satisfied along the
4867 obj->vernum = maxvernum + 1;
4868 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4871 while (vd != NULL) {
4872 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4873 vernum = VER_DEF_IDX(vd->vd_ndx);
4874 assert(vernum <= maxvernum);
4875 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4876 obj->vertab[vernum].hash = vd->vd_hash;
4877 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4878 obj->vertab[vernum].file = NULL;
4879 obj->vertab[vernum].flags = 0;
4881 if (vd->vd_next == 0)
4883 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4887 while (vn != NULL) {
4888 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4891 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4893 if (check_object_provided_version(obj, depobj, vna))
4895 vernum = VER_NEED_IDX(vna->vna_other);
4896 assert(vernum <= maxvernum);
4897 obj->vertab[vernum].hash = vna->vna_hash;
4898 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4899 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4900 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4901 VER_INFO_HIDDEN : 0;
4902 if (vna->vna_next == 0)
4904 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4906 if (vn->vn_next == 0)
4908 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4914 rtld_verify_versions(const Objlist *objlist)
4916 Objlist_Entry *entry;
4920 STAILQ_FOREACH(entry, objlist, link) {
4922 * Skip dummy objects or objects that have their version requirements
4925 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4927 if (rtld_verify_object_versions(entry->obj) == -1) {
4929 if (ld_tracing == NULL)
4933 if (rc == 0 || ld_tracing != NULL)
4934 rc = rtld_verify_object_versions(&obj_rtld);
4939 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4944 vernum = VER_NDX(obj->versyms[symnum]);
4945 if (vernum >= obj->vernum) {
4946 _rtld_error("%s: symbol %s has wrong verneed value %d",
4947 obj->path, obj->strtab + symnum, vernum);
4948 } else if (obj->vertab[vernum].hash != 0) {
4949 return &obj->vertab[vernum];
4956 _rtld_get_stack_prot(void)
4959 return (stack_prot);
4963 _rtld_is_dlopened(void *arg)
4966 RtldLockState lockstate;
4969 rlock_acquire(rtld_bind_lock, &lockstate);
4972 obj = obj_from_addr(arg);
4974 _rtld_error("No shared object contains address");
4975 lock_release(rtld_bind_lock, &lockstate);
4978 res = obj->dlopened ? 1 : 0;
4979 lock_release(rtld_bind_lock, &lockstate);
4984 map_stacks_exec(RtldLockState *lockstate)
4986 void (*thr_map_stacks_exec)(void);
4988 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4990 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4991 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4992 if (thr_map_stacks_exec != NULL) {
4993 stack_prot |= PROT_EXEC;
4994 thr_map_stacks_exec();
4999 symlook_init(SymLook *dst, const char *name)
5002 bzero(dst, sizeof(*dst));
5004 dst->hash = elf_hash(name);
5005 dst->hash_gnu = gnu_hash(name);
5009 symlook_init_from_req(SymLook *dst, const SymLook *src)
5012 dst->name = src->name;
5013 dst->hash = src->hash;
5014 dst->hash_gnu = src->hash_gnu;
5015 dst->ventry = src->ventry;
5016 dst->flags = src->flags;
5017 dst->defobj_out = NULL;
5018 dst->sym_out = NULL;
5019 dst->lockstate = src->lockstate;
5024 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
5027 parse_libdir(const char *str)
5029 static const int RADIX = 10; /* XXXJA: possibly support hex? */
5036 for (c = *str; c != '\0'; c = *++str) {
5037 if (c < '0' || c > '9')
5044 /* Make sure we actually parsed something. */
5046 _rtld_error("failed to parse directory FD from '%s'", str);
5053 * Overrides for libc_pic-provided functions.
5057 __getosreldate(void)
5067 oid[1] = KERN_OSRELDATE;
5069 len = sizeof(osrel);
5070 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5071 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5083 void (*__cleanup)(void);
5084 int __isthreaded = 0;
5085 int _thread_autoinit_dummy_decl = 1;
5088 * No unresolved symbols for rtld.
5091 __pthread_cxa_finalize(struct dl_phdr_info *a)
5096 __stack_chk_fail(void)
5099 _rtld_error("stack overflow detected; terminated");
5102 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
5108 _rtld_error("buffer overflow detected; terminated");
5113 rtld_strerror(int errnum)
5116 if (errnum < 0 || errnum >= sys_nerr)
5117 return ("Unknown error");
5118 return (sys_errlist[errnum]);