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 struct obj_entry_q obj_list; /* Queue of all loaded objects */
184 static Obj_Entry *obj_main; /* The main program shared object */
185 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
186 static unsigned int obj_count; /* Number of objects in obj_list */
187 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
189 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
190 STAILQ_HEAD_INITIALIZER(list_global);
191 static Objlist list_main = /* Objects loaded at program startup */
192 STAILQ_HEAD_INITIALIZER(list_main);
193 static Objlist list_fini = /* Objects needing fini() calls */
194 STAILQ_HEAD_INITIALIZER(list_fini);
196 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
198 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
200 extern Elf_Dyn _DYNAMIC;
201 #pragma weak _DYNAMIC
202 #ifndef RTLD_IS_DYNAMIC
203 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
206 int dlclose(void *) __exported;
207 char *dlerror(void) __exported;
208 void *dlopen(const char *, int) __exported;
209 void *fdlopen(int, int) __exported;
210 void *dlsym(void *, const char *) __exported;
211 dlfunc_t dlfunc(void *, const char *) __exported;
212 void *dlvsym(void *, const char *, const char *) __exported;
213 int dladdr(const void *, Dl_info *) __exported;
214 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
215 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
216 int dlinfo(void *, int , void *) __exported;
217 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
218 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
219 int _rtld_get_stack_prot(void) __exported;
220 int _rtld_is_dlopened(void *) __exported;
221 void _rtld_error(const char *, ...) __exported;
223 int npagesizes, osreldate;
226 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
228 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
229 static int max_stack_flags;
232 * Global declarations normally provided by crt1. The dynamic linker is
233 * not built with crt1, so we have to provide them ourselves.
239 * Used to pass argc, argv to init functions.
245 * Globals to control TLS allocation.
247 size_t tls_last_offset; /* Static TLS offset of last module */
248 size_t tls_last_size; /* Static TLS size of last module */
249 size_t tls_static_space; /* Static TLS space allocated */
250 size_t tls_static_max_align;
251 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
252 int tls_max_index = 1; /* Largest module index allocated */
254 bool ld_library_path_rpath = false;
257 * Globals for path names, and such
259 char *ld_elf_hints_default = _PATH_ELF_HINTS;
260 char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
261 char *ld_path_rtld = _PATH_RTLD;
262 char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
263 char *ld_env_prefix = LD_;
266 * Fill in a DoneList with an allocation large enough to hold all of
267 * the currently-loaded objects. Keep this as a macro since it calls
268 * alloca and we want that to occur within the scope of the caller.
270 #define donelist_init(dlp) \
271 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
272 assert((dlp)->objs != NULL), \
273 (dlp)->num_alloc = obj_count, \
276 #define UTRACE_DLOPEN_START 1
277 #define UTRACE_DLOPEN_STOP 2
278 #define UTRACE_DLCLOSE_START 3
279 #define UTRACE_DLCLOSE_STOP 4
280 #define UTRACE_LOAD_OBJECT 5
281 #define UTRACE_UNLOAD_OBJECT 6
282 #define UTRACE_ADD_RUNDEP 7
283 #define UTRACE_PRELOAD_FINISHED 8
284 #define UTRACE_INIT_CALL 9
285 #define UTRACE_FINI_CALL 10
286 #define UTRACE_DLSYM_START 11
287 #define UTRACE_DLSYM_STOP 12
290 char sig[4]; /* 'RTLD' */
293 void *mapbase; /* Used for 'parent' and 'init/fini' */
295 int refcnt; /* Used for 'mode' */
296 char name[MAXPATHLEN];
299 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
300 if (ld_utrace != NULL) \
301 ld_utrace_log(e, h, mb, ms, r, n); \
305 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
306 int refcnt, const char *name)
308 struct utrace_rtld ut;
316 ut.mapbase = mapbase;
317 ut.mapsize = mapsize;
319 bzero(ut.name, sizeof(ut.name));
321 strlcpy(ut.name, name, sizeof(ut.name));
322 utrace(&ut, sizeof(ut));
325 #ifdef RTLD_VARIANT_ENV_NAMES
327 * construct the env variable based on the type of binary that's
330 static inline const char *
333 static char buffer[128];
335 strlcpy(buffer, ld_env_prefix, sizeof(buffer));
336 strlcat(buffer, var, sizeof(buffer));
344 * Main entry point for dynamic linking. The first argument is the
345 * stack pointer. The stack is expected to be laid out as described
346 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
347 * Specifically, the stack pointer points to a word containing
348 * ARGC. Following that in the stack is a null-terminated sequence
349 * of pointers to argument strings. Then comes a null-terminated
350 * sequence of pointers to environment strings. Finally, there is a
351 * sequence of "auxiliary vector" entries.
353 * The second argument points to a place to store the dynamic linker's
354 * exit procedure pointer and the third to a place to store the main
357 * The return value is the main program's entry point.
360 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
362 Elf_Auxinfo *aux_info[AT_COUNT];
370 Objlist_Entry *entry;
372 Obj_Entry *preload_tail;
373 Obj_Entry *last_interposer;
375 RtldLockState lockstate;
376 char *library_path_rpath;
381 * On entry, the dynamic linker itself has not been relocated yet.
382 * Be very careful not to reference any global data until after
383 * init_rtld has returned. It is OK to reference file-scope statics
384 * and string constants, and to call static and global functions.
387 /* Find the auxiliary vector on the stack. */
390 sp += argc + 1; /* Skip over arguments and NULL terminator */
392 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
394 aux = (Elf_Auxinfo *) sp;
396 /* Digest the auxiliary vector. */
397 for (i = 0; i < AT_COUNT; i++)
399 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
400 if (auxp->a_type < AT_COUNT)
401 aux_info[auxp->a_type] = auxp;
404 /* Initialize and relocate ourselves. */
405 assert(aux_info[AT_BASE] != NULL);
406 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
408 __progname = obj_rtld.path;
409 argv0 = argv[0] != NULL ? argv[0] : "(null)";
414 if (aux_info[AT_CANARY] != NULL &&
415 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
416 i = aux_info[AT_CANARYLEN]->a_un.a_val;
417 if (i > sizeof(__stack_chk_guard))
418 i = sizeof(__stack_chk_guard);
419 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
424 len = sizeof(__stack_chk_guard);
425 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
426 len != sizeof(__stack_chk_guard)) {
427 /* If sysctl was unsuccessful, use the "terminator canary". */
428 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
429 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
430 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
431 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
435 trust = !issetugid();
437 md_abi_variant_hook(aux_info);
439 ld_bind_now = getenv(_LD("BIND_NOW"));
441 * If the process is tainted, then we un-set the dangerous environment
442 * variables. The process will be marked as tainted until setuid(2)
443 * is called. If any child process calls setuid(2) we do not want any
444 * future processes to honor the potentially un-safe variables.
447 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) ||
448 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) ||
449 unsetenv(_LD("LIBMAP_DISABLE")) ||
450 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) ||
451 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) {
452 _rtld_error("environment corrupt; aborting");
456 ld_debug = getenv(_LD("DEBUG"));
457 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL;
458 libmap_override = getenv(_LD("LIBMAP"));
459 ld_library_path = getenv(_LD("LIBRARY_PATH"));
460 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS"));
461 ld_preload = getenv(_LD("PRELOAD"));
462 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH"));
463 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL;
464 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH"));
465 if (library_path_rpath != NULL) {
466 if (library_path_rpath[0] == 'y' ||
467 library_path_rpath[0] == 'Y' ||
468 library_path_rpath[0] == '1')
469 ld_library_path_rpath = true;
471 ld_library_path_rpath = false;
473 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
474 (ld_library_path != NULL) || (ld_preload != NULL) ||
475 (ld_elf_hints_path != NULL) || ld_loadfltr;
476 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS"));
477 ld_utrace = getenv(_LD("UTRACE"));
479 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
480 ld_elf_hints_path = ld_elf_hints_default;
482 if (ld_debug != NULL && *ld_debug != '\0')
484 dbg("%s is initialized, base address = %p", __progname,
485 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
486 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
487 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
489 dbg("initializing thread locks");
493 * Load the main program, or process its program header if it is
496 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
497 int fd = aux_info[AT_EXECFD]->a_un.a_val;
498 dbg("loading main program");
499 obj_main = map_object(fd, argv0, NULL);
501 if (obj_main == NULL)
503 max_stack_flags = obj->stack_flags;
504 } else { /* Main program already loaded. */
505 const Elf_Phdr *phdr;
509 dbg("processing main program's program header");
510 assert(aux_info[AT_PHDR] != NULL);
511 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
512 assert(aux_info[AT_PHNUM] != NULL);
513 phnum = aux_info[AT_PHNUM]->a_un.a_val;
514 assert(aux_info[AT_PHENT] != NULL);
515 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
516 assert(aux_info[AT_ENTRY] != NULL);
517 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
518 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
522 if (aux_info[AT_EXECPATH] != 0) {
524 char buf[MAXPATHLEN];
526 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
527 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
528 if (kexecpath[0] == '/')
529 obj_main->path = kexecpath;
530 else if (getcwd(buf, sizeof(buf)) == NULL ||
531 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
532 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
533 obj_main->path = xstrdup(argv0);
535 obj_main->path = xstrdup(buf);
537 dbg("No AT_EXECPATH");
538 obj_main->path = xstrdup(argv0);
540 dbg("obj_main path %s", obj_main->path);
541 obj_main->mainprog = true;
543 if (aux_info[AT_STACKPROT] != NULL &&
544 aux_info[AT_STACKPROT]->a_un.a_val != 0)
545 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
549 * Get the actual dynamic linker pathname from the executable if
550 * possible. (It should always be possible.) That ensures that
551 * gdb will find the right dynamic linker even if a non-standard
554 if (obj_main->interp != NULL &&
555 strcmp(obj_main->interp, obj_rtld.path) != 0) {
557 obj_rtld.path = xstrdup(obj_main->interp);
558 __progname = obj_rtld.path;
562 digest_dynamic(obj_main, 0);
563 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
564 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
565 obj_main->dynsymcount);
567 linkmap_add(obj_main);
568 linkmap_add(&obj_rtld);
570 /* Link the main program into the list of objects. */
571 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
575 /* Initialize a fake symbol for resolving undefined weak references. */
576 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
577 sym_zero.st_shndx = SHN_UNDEF;
578 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
581 libmap_disable = (bool)lm_init(libmap_override);
583 dbg("loading LD_PRELOAD libraries");
584 if (load_preload_objects() == -1)
586 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
588 dbg("loading needed objects");
589 if (load_needed_objects(obj_main, 0) == -1)
592 /* Make a list of all objects loaded at startup. */
593 last_interposer = obj_main;
594 TAILQ_FOREACH(obj, &obj_list, 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(globallist_curr(TAILQ_FIRST(&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(globallist_curr(TAILQ_FIRST(&obj_list)),
664 preload_tail, &initlist);
666 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
668 map_stacks_exec(NULL);
670 dbg("resolving ifuncs");
671 if (resolve_objects_ifunc(obj_main,
672 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
676 if (!obj_main->crt_no_init) {
678 * Make sure we don't call the main program's init and fini
679 * functions for binaries linked with old crt1 which calls
682 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
683 obj_main->preinit_array = obj_main->init_array =
684 obj_main->fini_array = (Elf_Addr)NULL;
687 wlock_acquire(rtld_bind_lock, &lockstate);
688 if (obj_main->crt_no_init)
690 objlist_call_init(&initlist, &lockstate);
691 _r_debug_postinit(&obj_main->linkmap);
692 objlist_clear(&initlist);
693 dbg("loading filtees");
694 TAILQ_FOREACH(obj, &obj_list, next) {
697 if (ld_loadfltr || obj->z_loadfltr)
698 load_filtees(obj, 0, &lockstate);
700 lock_release(rtld_bind_lock, &lockstate);
702 dbg("transferring control to program entry point = %p", obj_main->entry);
704 /* Return the exit procedure and the program entry point. */
705 *exit_proc = rtld_exit;
707 return (func_ptr_type) obj_main->entry;
711 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
716 ptr = (void *)make_function_pointer(def, obj);
717 target = ((Elf_Addr (*)(void))ptr)();
718 return ((void *)target);
722 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
726 const Obj_Entry *defobj;
729 RtldLockState lockstate;
731 rlock_acquire(rtld_bind_lock, &lockstate);
732 if (sigsetjmp(lockstate.env, 0) != 0)
733 lock_upgrade(rtld_bind_lock, &lockstate);
735 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
737 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
739 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
740 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
744 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
745 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
747 target = (Elf_Addr)(defobj->relocbase + def->st_value);
749 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
750 defobj->strtab + def->st_name, basename(obj->path),
751 (void *)target, basename(defobj->path));
754 * Write the new contents for the jmpslot. Note that depending on
755 * architecture, the value which we need to return back to the
756 * lazy binding trampoline may or may not be the target
757 * address. The value returned from reloc_jmpslot() is the value
758 * that the trampoline needs.
760 target = reloc_jmpslot(where, target, defobj, obj, rel);
761 lock_release(rtld_bind_lock, &lockstate);
766 * Error reporting function. Use it like printf. If formats the message
767 * into a buffer, and sets things up so that the next call to dlerror()
768 * will return the message.
771 _rtld_error(const char *fmt, ...)
773 static char buf[512];
777 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
783 * Return a dynamically-allocated copy of the current error message, if any.
788 return error_message == NULL ? NULL : xstrdup(error_message);
792 * Restore the current error message from a copy which was previously saved
793 * by errmsg_save(). The copy is freed.
796 errmsg_restore(char *saved_msg)
798 if (saved_msg == NULL)
799 error_message = NULL;
801 _rtld_error("%s", saved_msg);
807 basename(const char *name)
809 const char *p = strrchr(name, '/');
810 return p != NULL ? p + 1 : name;
813 static struct utsname uts;
816 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
817 const char *subst, bool may_free)
819 char *p, *p1, *res, *resp;
820 int subst_len, kw_len, subst_count, old_len, new_len;
825 * First, count the number of the keyword occurences, to
826 * preallocate the final string.
828 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
835 * If the keyword is not found, just return.
837 * Return non-substituted string if resolution failed. We
838 * cannot do anything more reasonable, the failure mode of the
839 * caller is unresolved library anyway.
841 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
842 return (may_free ? real : xstrdup(real));
844 subst = obj->origin_path;
847 * There is indeed something to substitute. Calculate the
848 * length of the resulting string, and allocate it.
850 subst_len = strlen(subst);
851 old_len = strlen(real);
852 new_len = old_len + (subst_len - kw_len) * subst_count;
853 res = xmalloc(new_len + 1);
856 * Now, execute the substitution loop.
858 for (p = real, resp = res, *resp = '\0';;) {
861 /* Copy the prefix before keyword. */
862 memcpy(resp, p, p1 - p);
864 /* Keyword replacement. */
865 memcpy(resp, subst, subst_len);
873 /* Copy to the end of string and finish. */
881 origin_subst(Obj_Entry *obj, char *real)
883 char *res1, *res2, *res3, *res4;
885 if (obj == NULL || !trust)
886 return (xstrdup(real));
887 if (uts.sysname[0] == '\0') {
888 if (uname(&uts) != 0) {
889 _rtld_error("utsname failed: %d", errno);
893 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false);
894 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
895 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
896 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
903 const char *msg = dlerror();
907 rtld_fdputstr(STDERR_FILENO, msg);
908 rtld_fdputchar(STDERR_FILENO, '\n');
913 * Process a shared object's DYNAMIC section, and save the important
914 * information in its Obj_Entry structure.
917 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
918 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
921 Needed_Entry **needed_tail = &obj->needed;
922 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
923 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
924 const Elf_Hashelt *hashtab;
925 const Elf32_Word *hashval;
926 Elf32_Word bkt, nmaskwords;
928 int plttype = DT_REL;
934 obj->bind_now = false;
935 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
936 switch (dynp->d_tag) {
939 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
943 obj->relsize = dynp->d_un.d_val;
947 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
951 obj->pltrel = (const Elf_Rel *)
952 (obj->relocbase + dynp->d_un.d_ptr);
956 obj->pltrelsize = dynp->d_un.d_val;
960 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
964 obj->relasize = dynp->d_un.d_val;
968 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
972 plttype = dynp->d_un.d_val;
973 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
977 obj->symtab = (const Elf_Sym *)
978 (obj->relocbase + dynp->d_un.d_ptr);
982 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
986 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
990 obj->strsize = dynp->d_un.d_val;
994 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
999 obj->verneednum = dynp->d_un.d_val;
1003 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
1008 obj->verdefnum = dynp->d_un.d_val;
1012 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1018 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1020 obj->nbuckets = hashtab[0];
1021 obj->nchains = hashtab[1];
1022 obj->buckets = hashtab + 2;
1023 obj->chains = obj->buckets + obj->nbuckets;
1024 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1025 obj->buckets != NULL;
1031 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1033 obj->nbuckets_gnu = hashtab[0];
1034 obj->symndx_gnu = hashtab[1];
1035 nmaskwords = hashtab[2];
1036 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1037 obj->maskwords_bm_gnu = nmaskwords - 1;
1038 obj->shift2_gnu = hashtab[3];
1039 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
1040 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1041 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1043 /* Number of bitmask words is required to be power of 2 */
1044 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1045 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1051 Needed_Entry *nep = NEW(Needed_Entry);
1052 nep->name = dynp->d_un.d_val;
1057 needed_tail = &nep->next;
1063 Needed_Entry *nep = NEW(Needed_Entry);
1064 nep->name = dynp->d_un.d_val;
1068 *needed_filtees_tail = nep;
1069 needed_filtees_tail = &nep->next;
1075 Needed_Entry *nep = NEW(Needed_Entry);
1076 nep->name = dynp->d_un.d_val;
1080 *needed_aux_filtees_tail = nep;
1081 needed_aux_filtees_tail = &nep->next;
1086 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1090 obj->textrel = true;
1094 obj->symbolic = true;
1099 * We have to wait until later to process this, because we
1100 * might not have gotten the address of the string table yet.
1110 *dyn_runpath = dynp;
1114 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1117 case DT_PREINIT_ARRAY:
1118 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1121 case DT_PREINIT_ARRAYSZ:
1122 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1126 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1129 case DT_INIT_ARRAYSZ:
1130 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1134 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1138 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1141 case DT_FINI_ARRAYSZ:
1142 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1146 * Don't process DT_DEBUG on MIPS as the dynamic section
1147 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1153 dbg("Filling in DT_DEBUG entry");
1154 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1159 if (dynp->d_un.d_val & DF_ORIGIN)
1160 obj->z_origin = true;
1161 if (dynp->d_un.d_val & DF_SYMBOLIC)
1162 obj->symbolic = true;
1163 if (dynp->d_un.d_val & DF_TEXTREL)
1164 obj->textrel = true;
1165 if (dynp->d_un.d_val & DF_BIND_NOW)
1166 obj->bind_now = true;
1167 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1171 case DT_MIPS_LOCAL_GOTNO:
1172 obj->local_gotno = dynp->d_un.d_val;
1175 case DT_MIPS_SYMTABNO:
1176 obj->symtabno = dynp->d_un.d_val;
1179 case DT_MIPS_GOTSYM:
1180 obj->gotsym = dynp->d_un.d_val;
1183 case DT_MIPS_RLD_MAP:
1184 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1188 #ifdef __powerpc64__
1189 case DT_PPC64_GLINK:
1190 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1195 if (dynp->d_un.d_val & DF_1_NOOPEN)
1196 obj->z_noopen = true;
1197 if (dynp->d_un.d_val & DF_1_ORIGIN)
1198 obj->z_origin = true;
1199 if (dynp->d_un.d_val & DF_1_GLOBAL)
1200 obj->z_global = true;
1201 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1202 obj->bind_now = true;
1203 if (dynp->d_un.d_val & DF_1_NODELETE)
1204 obj->z_nodelete = true;
1205 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1206 obj->z_loadfltr = true;
1207 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1208 obj->z_interpose = true;
1209 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1210 obj->z_nodeflib = true;
1215 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1222 obj->traced = false;
1224 if (plttype == DT_RELA) {
1225 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1227 obj->pltrelasize = obj->pltrelsize;
1228 obj->pltrelsize = 0;
1231 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1232 if (obj->valid_hash_sysv)
1233 obj->dynsymcount = obj->nchains;
1234 else if (obj->valid_hash_gnu) {
1235 obj->dynsymcount = 0;
1236 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1237 if (obj->buckets_gnu[bkt] == 0)
1239 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1242 while ((*hashval++ & 1u) == 0);
1244 obj->dynsymcount += obj->symndx_gnu;
1249 obj_resolve_origin(Obj_Entry *obj)
1252 if (obj->origin_path != NULL)
1254 obj->origin_path = xmalloc(PATH_MAX);
1255 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1259 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1260 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1263 if (obj->z_origin && !obj_resolve_origin(obj))
1266 if (dyn_runpath != NULL) {
1267 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1268 obj->runpath = origin_subst(obj, obj->runpath);
1269 } else if (dyn_rpath != NULL) {
1270 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1271 obj->rpath = origin_subst(obj, obj->rpath);
1273 if (dyn_soname != NULL)
1274 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1278 digest_dynamic(Obj_Entry *obj, int early)
1280 const Elf_Dyn *dyn_rpath;
1281 const Elf_Dyn *dyn_soname;
1282 const Elf_Dyn *dyn_runpath;
1284 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1285 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1289 * Process a shared object's program header. This is used only for the
1290 * main program, when the kernel has already loaded the main program
1291 * into memory before calling the dynamic linker. It creates and
1292 * returns an Obj_Entry structure.
1295 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1298 const Elf_Phdr *phlimit = phdr + phnum;
1300 Elf_Addr note_start, note_end;
1304 for (ph = phdr; ph < phlimit; ph++) {
1305 if (ph->p_type != PT_PHDR)
1309 obj->phsize = ph->p_memsz;
1310 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1314 obj->stack_flags = PF_X | PF_R | PF_W;
1316 for (ph = phdr; ph < phlimit; ph++) {
1317 switch (ph->p_type) {
1320 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1324 if (nsegs == 0) { /* First load segment */
1325 obj->vaddrbase = trunc_page(ph->p_vaddr);
1326 obj->mapbase = obj->vaddrbase + obj->relocbase;
1327 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1329 } else { /* Last load segment */
1330 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1337 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1342 obj->tlssize = ph->p_memsz;
1343 obj->tlsalign = ph->p_align;
1344 obj->tlsinitsize = ph->p_filesz;
1345 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1349 obj->stack_flags = ph->p_flags;
1353 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1354 obj->relro_size = round_page(ph->p_memsz);
1358 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1359 note_end = note_start + ph->p_filesz;
1360 digest_notes(obj, note_start, note_end);
1365 _rtld_error("%s: too few PT_LOAD segments", path);
1374 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1376 const Elf_Note *note;
1377 const char *note_name;
1380 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1381 note = (const Elf_Note *)((const char *)(note + 1) +
1382 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1383 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1384 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1385 note->n_descsz != sizeof(int32_t))
1387 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1388 note->n_type != NT_FREEBSD_NOINIT_TAG)
1390 note_name = (const char *)(note + 1);
1391 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1392 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1394 switch (note->n_type) {
1395 case NT_FREEBSD_ABI_TAG:
1396 /* FreeBSD osrel note */
1397 p = (uintptr_t)(note + 1);
1398 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1399 obj->osrel = *(const int32_t *)(p);
1400 dbg("note osrel %d", obj->osrel);
1402 case NT_FREEBSD_NOINIT_TAG:
1403 /* FreeBSD 'crt does not call init' note */
1404 obj->crt_no_init = true;
1405 dbg("note crt_no_init");
1412 dlcheck(void *handle)
1416 TAILQ_FOREACH(obj, &obj_list, next) {
1417 if (obj == (Obj_Entry *) handle)
1421 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1422 _rtld_error("Invalid shared object handle %p", handle);
1429 * If the given object is already in the donelist, return true. Otherwise
1430 * add the object to the list and return false.
1433 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1437 for (i = 0; i < dlp->num_used; i++)
1438 if (dlp->objs[i] == obj)
1441 * Our donelist allocation should always be sufficient. But if
1442 * our threads locking isn't working properly, more shared objects
1443 * could have been loaded since we allocated the list. That should
1444 * never happen, but we'll handle it properly just in case it does.
1446 if (dlp->num_used < dlp->num_alloc)
1447 dlp->objs[dlp->num_used++] = obj;
1452 * Hash function for symbol table lookup. Don't even think about changing
1453 * this. It is specified by the System V ABI.
1456 elf_hash(const char *name)
1458 const unsigned char *p = (const unsigned char *) name;
1459 unsigned long h = 0;
1462 while (*p != '\0') {
1463 h = (h << 4) + *p++;
1464 if ((g = h & 0xf0000000) != 0)
1472 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1473 * unsigned in case it's implemented with a wider type.
1476 gnu_hash(const char *s)
1482 for (c = *s; c != '\0'; c = *++s)
1484 return (h & 0xffffffff);
1489 * Find the library with the given name, and return its full pathname.
1490 * The returned string is dynamically allocated. Generates an error
1491 * message and returns NULL if the library cannot be found.
1493 * If the second argument is non-NULL, then it refers to an already-
1494 * loaded shared object, whose library search path will be searched.
1496 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1497 * descriptor (which is close-on-exec) will be passed out via the third
1500 * The search order is:
1501 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1502 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1504 * DT_RUNPATH in the referencing file
1505 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1507 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1509 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1512 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1516 bool nodeflib, objgiven;
1518 objgiven = refobj != NULL;
1519 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1520 if (xname[0] != '/' && !trust) {
1521 _rtld_error("Absolute pathname required for shared object \"%s\"",
1525 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1526 __DECONST(char *, xname)));
1529 if (libmap_disable || !objgiven ||
1530 (name = lm_find(refobj->path, xname)) == NULL)
1531 name = (char *)xname;
1533 dbg(" Searching for \"%s\"", name);
1536 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1537 * back to pre-conforming behaviour if user requested so with
1538 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1541 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1542 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1544 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1545 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL ||
1546 (pathname = search_library_path(name, gethints(false))) != NULL ||
1547 (pathname = search_library_path(name, ld_standard_library_path)) != NULL)
1550 nodeflib = objgiven ? refobj->z_nodeflib : false;
1552 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1553 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1554 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1555 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1557 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1558 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL ||
1559 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1560 (objgiven && !nodeflib &&
1561 (pathname = search_library_path(name, ld_standard_library_path)) != NULL))
1565 if (objgiven && refobj->path != NULL) {
1566 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1567 name, basename(refobj->path));
1569 _rtld_error("Shared object \"%s\" not found", name);
1575 * Given a symbol number in a referencing object, find the corresponding
1576 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1577 * no definition was found. Returns a pointer to the Obj_Entry of the
1578 * defining object via the reference parameter DEFOBJ_OUT.
1581 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1582 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1583 RtldLockState *lockstate)
1587 const Obj_Entry *defobj;
1593 * If we have already found this symbol, get the information from
1596 if (symnum >= refobj->dynsymcount)
1597 return NULL; /* Bad object */
1598 if (cache != NULL && cache[symnum].sym != NULL) {
1599 *defobj_out = cache[symnum].obj;
1600 return cache[symnum].sym;
1603 ref = refobj->symtab + symnum;
1604 name = refobj->strtab + ref->st_name;
1609 * We don't have to do a full scale lookup if the symbol is local.
1610 * We know it will bind to the instance in this load module; to
1611 * which we already have a pointer (ie ref). By not doing a lookup,
1612 * we not only improve performance, but it also avoids unresolvable
1613 * symbols when local symbols are not in the hash table. This has
1614 * been seen with the ia64 toolchain.
1616 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1617 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1618 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1621 symlook_init(&req, name);
1623 req.ventry = fetch_ventry(refobj, symnum);
1624 req.lockstate = lockstate;
1625 res = symlook_default(&req, refobj);
1628 defobj = req.defobj_out;
1636 * If we found no definition and the reference is weak, treat the
1637 * symbol as having the value zero.
1639 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1645 *defobj_out = defobj;
1646 /* Record the information in the cache to avoid subsequent lookups. */
1647 if (cache != NULL) {
1648 cache[symnum].sym = def;
1649 cache[symnum].obj = defobj;
1652 if (refobj != &obj_rtld)
1653 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1659 * Return the search path from the ldconfig hints file, reading it if
1660 * necessary. If nostdlib is true, then the default search paths are
1661 * not added to result.
1663 * Returns NULL if there are problems with the hints file,
1664 * or if the search path there is empty.
1667 gethints(bool nostdlib)
1669 static char *hints, *filtered_path;
1670 struct elfhints_hdr hdr;
1671 struct fill_search_info_args sargs, hargs;
1672 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1673 struct dl_serpath *SLPpath, *hintpath;
1675 unsigned int SLPndx, hintndx, fndx, fcount;
1680 /* First call, read the hints file */
1681 if (hints == NULL) {
1682 /* Keep from trying again in case the hints file is bad. */
1685 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1687 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1688 hdr.magic != ELFHINTS_MAGIC ||
1693 p = xmalloc(hdr.dirlistlen + 1);
1694 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1695 read(fd, p, hdr.dirlistlen + 1) !=
1696 (ssize_t)hdr.dirlistlen + 1) {
1706 * If caller agreed to receive list which includes the default
1707 * paths, we are done. Otherwise, if we still did not
1708 * calculated filtered result, do it now.
1711 return (hints[0] != '\0' ? hints : NULL);
1712 if (filtered_path != NULL)
1716 * Obtain the list of all configured search paths, and the
1717 * list of the default paths.
1719 * First estimate the size of the results.
1721 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1723 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1726 sargs.request = RTLD_DI_SERINFOSIZE;
1727 sargs.serinfo = &smeta;
1728 hargs.request = RTLD_DI_SERINFOSIZE;
1729 hargs.serinfo = &hmeta;
1731 path_enumerate(ld_standard_library_path, fill_search_info, &sargs);
1732 path_enumerate(p, fill_search_info, &hargs);
1734 SLPinfo = xmalloc(smeta.dls_size);
1735 hintinfo = xmalloc(hmeta.dls_size);
1738 * Next fetch both sets of paths.
1740 sargs.request = RTLD_DI_SERINFO;
1741 sargs.serinfo = SLPinfo;
1742 sargs.serpath = &SLPinfo->dls_serpath[0];
1743 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1745 hargs.request = RTLD_DI_SERINFO;
1746 hargs.serinfo = hintinfo;
1747 hargs.serpath = &hintinfo->dls_serpath[0];
1748 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1750 path_enumerate(ld_standard_library_path, fill_search_info, &sargs);
1751 path_enumerate(p, fill_search_info, &hargs);
1754 * Now calculate the difference between two sets, by excluding
1755 * standard paths from the full set.
1759 filtered_path = xmalloc(hdr.dirlistlen + 1);
1760 hintpath = &hintinfo->dls_serpath[0];
1761 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1763 SLPpath = &SLPinfo->dls_serpath[0];
1765 * Check each standard path against current.
1767 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1768 /* matched, skip the path */
1769 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1777 * Not matched against any standard path, add the path
1778 * to result. Separate consequtive paths with ':'.
1781 filtered_path[fndx] = ':';
1785 flen = strlen(hintpath->dls_name);
1786 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1789 filtered_path[fndx] = '\0';
1795 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1799 init_dag(Obj_Entry *root)
1801 const Needed_Entry *needed;
1802 const Objlist_Entry *elm;
1805 if (root->dag_inited)
1807 donelist_init(&donelist);
1809 /* Root object belongs to own DAG. */
1810 objlist_push_tail(&root->dldags, root);
1811 objlist_push_tail(&root->dagmembers, root);
1812 donelist_check(&donelist, root);
1815 * Add dependencies of root object to DAG in breadth order
1816 * by exploiting the fact that each new object get added
1817 * to the tail of the dagmembers list.
1819 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1820 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1821 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1823 objlist_push_tail(&needed->obj->dldags, root);
1824 objlist_push_tail(&root->dagmembers, needed->obj);
1827 root->dag_inited = true;
1831 globallist_curr(const Obj_Entry *obj)
1838 return (__DECONST(Obj_Entry *, obj));
1839 obj = TAILQ_PREV(obj, obj_entry_q, next);
1844 globallist_next(const Obj_Entry *obj)
1848 obj = TAILQ_NEXT(obj, next);
1852 return (__DECONST(Obj_Entry *, obj));
1857 process_z(Obj_Entry *root)
1859 const Objlist_Entry *elm;
1863 * Walk over object DAG and process every dependent object
1864 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
1865 * to grow their own DAG.
1867 * For DF_1_GLOBAL, DAG is required for symbol lookups in
1868 * symlook_global() to work.
1870 * For DF_1_NODELETE, the DAG should have its reference upped.
1872 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1876 if (obj->z_nodelete && !obj->ref_nodel) {
1877 dbg("obj %s -z nodelete", obj->path);
1880 obj->ref_nodel = true;
1882 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
1883 dbg("obj %s -z global", obj->path);
1884 objlist_push_tail(&list_global, obj);
1890 * Initialize the dynamic linker. The argument is the address at which
1891 * the dynamic linker has been mapped into memory. The primary task of
1892 * this function is to relocate the dynamic linker.
1895 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1897 Obj_Entry objtmp; /* Temporary rtld object */
1898 const Elf_Dyn *dyn_rpath;
1899 const Elf_Dyn *dyn_soname;
1900 const Elf_Dyn *dyn_runpath;
1902 #ifdef RTLD_INIT_PAGESIZES_EARLY
1903 /* The page size is required by the dynamic memory allocator. */
1904 init_pagesizes(aux_info);
1908 * Conjure up an Obj_Entry structure for the dynamic linker.
1910 * The "path" member can't be initialized yet because string constants
1911 * cannot yet be accessed. Below we will set it correctly.
1913 memset(&objtmp, 0, sizeof(objtmp));
1916 objtmp.mapbase = mapbase;
1918 objtmp.relocbase = mapbase;
1920 if (RTLD_IS_DYNAMIC()) {
1921 objtmp.dynamic = rtld_dynamic(&objtmp);
1922 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1923 assert(objtmp.needed == NULL);
1924 #if !defined(__mips__)
1925 /* MIPS has a bogus DT_TEXTREL. */
1926 assert(!objtmp.textrel);
1930 * Temporarily put the dynamic linker entry into the object list, so
1931 * that symbols can be found.
1934 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1937 /* Initialize the object list. */
1938 TAILQ_INIT(&obj_list);
1940 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1941 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1943 #ifndef RTLD_INIT_PAGESIZES_EARLY
1944 /* The page size is required by the dynamic memory allocator. */
1945 init_pagesizes(aux_info);
1948 if (aux_info[AT_OSRELDATE] != NULL)
1949 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1951 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1953 /* Replace the path with a dynamically allocated copy. */
1954 obj_rtld.path = xstrdup(ld_path_rtld);
1956 r_debug.r_brk = r_debug_state;
1957 r_debug.r_state = RT_CONSISTENT;
1961 * Retrieve the array of supported page sizes. The kernel provides the page
1962 * sizes in increasing order.
1965 init_pagesizes(Elf_Auxinfo **aux_info)
1967 static size_t psa[MAXPAGESIZES];
1971 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
1973 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
1974 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
1977 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
1980 /* As a fallback, retrieve the base page size. */
1981 size = sizeof(psa[0]);
1982 if (aux_info[AT_PAGESZ] != NULL) {
1983 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
1987 mib[1] = HW_PAGESIZE;
1991 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
1992 _rtld_error("sysctl for hw.pagesize(s) failed");
1998 npagesizes = size / sizeof(pagesizes[0]);
1999 /* Discard any invalid entries at the end of the array. */
2000 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2005 * Add the init functions from a needed object list (and its recursive
2006 * needed objects) to "list". This is not used directly; it is a helper
2007 * function for initlist_add_objects(). The write lock must be held
2008 * when this function is called.
2011 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
2013 /* Recursively process the successor needed objects. */
2014 if (needed->next != NULL)
2015 initlist_add_neededs(needed->next, list);
2017 /* Process the current needed object. */
2018 if (needed->obj != NULL)
2019 initlist_add_objects(needed->obj, needed->obj, list);
2023 * Scan all of the DAGs rooted in the range of objects from "obj" to
2024 * "tail" and add their init functions to "list". This recurses over
2025 * the DAGs and ensure the proper init ordering such that each object's
2026 * needed libraries are initialized before the object itself. At the
2027 * same time, this function adds the objects to the global finalization
2028 * list "list_fini" in the opposite order. The write lock must be
2029 * held when this function is called.
2032 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2036 if (obj->init_scanned || obj->init_done)
2038 obj->init_scanned = true;
2040 /* Recursively process the successor objects. */
2041 nobj = globallist_next(obj);
2042 if (nobj != NULL && obj != tail)
2043 initlist_add_objects(nobj, tail, list);
2045 /* Recursively process the needed objects. */
2046 if (obj->needed != NULL)
2047 initlist_add_neededs(obj->needed, list);
2048 if (obj->needed_filtees != NULL)
2049 initlist_add_neededs(obj->needed_filtees, list);
2050 if (obj->needed_aux_filtees != NULL)
2051 initlist_add_neededs(obj->needed_aux_filtees, list);
2053 /* Add the object to the init list. */
2054 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
2055 obj->init_array != (Elf_Addr)NULL)
2056 objlist_push_tail(list, obj);
2058 /* Add the object to the global fini list in the reverse order. */
2059 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2060 && !obj->on_fini_list) {
2061 objlist_push_head(&list_fini, obj);
2062 obj->on_fini_list = true;
2067 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2071 free_needed_filtees(Needed_Entry *n)
2073 Needed_Entry *needed, *needed1;
2075 for (needed = n; needed != NULL; needed = needed->next) {
2076 if (needed->obj != NULL) {
2077 dlclose(needed->obj);
2081 for (needed = n; needed != NULL; needed = needed1) {
2082 needed1 = needed->next;
2088 unload_filtees(Obj_Entry *obj)
2091 free_needed_filtees(obj->needed_filtees);
2092 obj->needed_filtees = NULL;
2093 free_needed_filtees(obj->needed_aux_filtees);
2094 obj->needed_aux_filtees = NULL;
2095 obj->filtees_loaded = false;
2099 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2100 RtldLockState *lockstate)
2103 for (; needed != NULL; needed = needed->next) {
2104 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2105 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2106 RTLD_LOCAL, lockstate);
2111 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2114 lock_restart_for_upgrade(lockstate);
2115 if (!obj->filtees_loaded) {
2116 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2117 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2118 obj->filtees_loaded = true;
2123 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2127 for (; needed != NULL; needed = needed->next) {
2128 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2129 flags & ~RTLD_LO_NOLOAD);
2130 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2137 * Given a shared object, traverse its list of needed objects, and load
2138 * each of them. Returns 0 on success. Generates an error message and
2139 * returns -1 on failure.
2142 load_needed_objects(Obj_Entry *first, int flags)
2147 TAILQ_FOREACH_FROM(obj, &obj_list, next) {
2150 if (process_needed(obj, obj->needed, flags) == -1)
2157 load_preload_objects(void)
2159 char *p = ld_preload;
2161 static const char delim[] = " \t:;";
2166 p += strspn(p, delim);
2167 while (*p != '\0') {
2168 size_t len = strcspn(p, delim);
2173 obj = load_object(p, -1, NULL, 0);
2175 return -1; /* XXX - cleanup */
2176 obj->z_interpose = true;
2179 p += strspn(p, delim);
2181 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2186 printable_path(const char *path)
2189 return (path == NULL ? "<unknown>" : path);
2193 * Load a shared object into memory, if it is not already loaded. The
2194 * object may be specified by name or by user-supplied file descriptor
2195 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2198 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2202 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2211 TAILQ_FOREACH(obj, &obj_list, next) {
2214 if (object_match_name(obj, name))
2218 path = find_library(name, refobj, &fd);
2226 * search_library_pathfds() opens a fresh file descriptor for the
2227 * library, so there is no need to dup().
2229 } else if (fd_u == -1) {
2231 * If we didn't find a match by pathname, or the name is not
2232 * supplied, open the file and check again by device and inode.
2233 * This avoids false mismatches caused by multiple links or ".."
2236 * To avoid a race, we open the file and use fstat() rather than
2239 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2240 _rtld_error("Cannot open \"%s\"", path);
2245 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2247 _rtld_error("Cannot dup fd");
2252 if (fstat(fd, &sb) == -1) {
2253 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2258 TAILQ_FOREACH(obj, &obj_list, next) {
2261 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2264 if (obj != NULL && name != NULL) {
2265 object_add_name(obj, name);
2270 if (flags & RTLD_LO_NOLOAD) {
2276 /* First use of this object, so we must map it in */
2277 obj = do_load_object(fd, name, path, &sb, flags);
2286 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2293 * but first, make sure that environment variables haven't been
2294 * used to circumvent the noexec flag on a filesystem.
2296 if (dangerous_ld_env) {
2297 if (fstatfs(fd, &fs) != 0) {
2298 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2301 if (fs.f_flags & MNT_NOEXEC) {
2302 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2306 dbg("loading \"%s\"", printable_path(path));
2307 obj = map_object(fd, printable_path(path), sbp);
2312 * If DT_SONAME is present in the object, digest_dynamic2 already
2313 * added it to the object names.
2316 object_add_name(obj, name);
2318 digest_dynamic(obj, 0);
2319 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2320 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2321 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2323 dbg("refusing to load non-loadable \"%s\"", obj->path);
2324 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2325 munmap(obj->mapbase, obj->mapsize);
2330 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2331 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2334 linkmap_add(obj); /* for GDB & dlinfo() */
2335 max_stack_flags |= obj->stack_flags;
2337 dbg(" %p .. %p: %s", obj->mapbase,
2338 obj->mapbase + obj->mapsize - 1, obj->path);
2340 dbg(" WARNING: %s has impure text", obj->path);
2341 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2348 obj_from_addr(const void *addr)
2352 TAILQ_FOREACH(obj, &obj_list, next) {
2355 if (addr < (void *) obj->mapbase)
2357 if (addr < (void *) (obj->mapbase + obj->mapsize))
2366 Elf_Addr *preinit_addr;
2369 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2370 if (preinit_addr == NULL)
2373 for (index = 0; index < obj_main->preinit_array_num; index++) {
2374 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2375 dbg("calling preinit function for %s at %p", obj_main->path,
2376 (void *)preinit_addr[index]);
2377 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2378 0, 0, obj_main->path);
2379 call_init_pointer(obj_main, preinit_addr[index]);
2385 * Call the finalization functions for each of the objects in "list"
2386 * belonging to the DAG of "root" and referenced once. If NULL "root"
2387 * is specified, every finalization function will be called regardless
2388 * of the reference count and the list elements won't be freed. All of
2389 * the objects are expected to have non-NULL fini functions.
2392 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2396 Elf_Addr *fini_addr;
2399 assert(root == NULL || root->refcount == 1);
2402 * Preserve the current error message since a fini function might
2403 * call into the dynamic linker and overwrite it.
2405 saved_msg = errmsg_save();
2407 STAILQ_FOREACH(elm, list, link) {
2408 if (root != NULL && (elm->obj->refcount != 1 ||
2409 objlist_find(&root->dagmembers, elm->obj) == NULL))
2411 /* Remove object from fini list to prevent recursive invocation. */
2412 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2414 * XXX: If a dlopen() call references an object while the
2415 * fini function is in progress, we might end up trying to
2416 * unload the referenced object in dlclose() or the object
2417 * won't be unloaded although its fini function has been
2420 lock_release(rtld_bind_lock, lockstate);
2423 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2424 * When this happens, DT_FINI_ARRAY is processed first.
2426 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2427 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2428 for (index = elm->obj->fini_array_num - 1; index >= 0;
2430 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2431 dbg("calling fini function for %s at %p",
2432 elm->obj->path, (void *)fini_addr[index]);
2433 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2434 (void *)fini_addr[index], 0, 0, elm->obj->path);
2435 call_initfini_pointer(elm->obj, fini_addr[index]);
2439 if (elm->obj->fini != (Elf_Addr)NULL) {
2440 dbg("calling fini function for %s at %p", elm->obj->path,
2441 (void *)elm->obj->fini);
2442 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2443 0, 0, elm->obj->path);
2444 call_initfini_pointer(elm->obj, elm->obj->fini);
2446 wlock_acquire(rtld_bind_lock, lockstate);
2447 /* No need to free anything if process is going down. */
2451 * We must restart the list traversal after every fini call
2452 * because a dlclose() call from the fini function or from
2453 * another thread might have modified the reference counts.
2457 } while (elm != NULL);
2458 errmsg_restore(saved_msg);
2462 * Call the initialization functions for each of the objects in
2463 * "list". All of the objects are expected to have non-NULL init
2467 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2472 Elf_Addr *init_addr;
2476 * Clean init_scanned flag so that objects can be rechecked and
2477 * possibly initialized earlier if any of vectors called below
2478 * cause the change by using dlopen.
2480 TAILQ_FOREACH(obj, &obj_list, next) {
2483 obj->init_scanned = false;
2487 * Preserve the current error message since an init function might
2488 * call into the dynamic linker and overwrite it.
2490 saved_msg = errmsg_save();
2491 STAILQ_FOREACH(elm, list, link) {
2492 if (elm->obj->init_done) /* Initialized early. */
2495 * Race: other thread might try to use this object before current
2496 * one completes the initilization. Not much can be done here
2497 * without better locking.
2499 elm->obj->init_done = true;
2500 lock_release(rtld_bind_lock, lockstate);
2503 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2504 * When this happens, DT_INIT is processed first.
2506 if (elm->obj->init != (Elf_Addr)NULL) {
2507 dbg("calling init function for %s at %p", elm->obj->path,
2508 (void *)elm->obj->init);
2509 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2510 0, 0, elm->obj->path);
2511 call_initfini_pointer(elm->obj, elm->obj->init);
2513 init_addr = (Elf_Addr *)elm->obj->init_array;
2514 if (init_addr != NULL) {
2515 for (index = 0; index < elm->obj->init_array_num; index++) {
2516 if (init_addr[index] != 0 && init_addr[index] != 1) {
2517 dbg("calling init function for %s at %p", elm->obj->path,
2518 (void *)init_addr[index]);
2519 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2520 (void *)init_addr[index], 0, 0, elm->obj->path);
2521 call_init_pointer(elm->obj, init_addr[index]);
2525 wlock_acquire(rtld_bind_lock, lockstate);
2527 errmsg_restore(saved_msg);
2531 objlist_clear(Objlist *list)
2535 while (!STAILQ_EMPTY(list)) {
2536 elm = STAILQ_FIRST(list);
2537 STAILQ_REMOVE_HEAD(list, link);
2542 static Objlist_Entry *
2543 objlist_find(Objlist *list, const Obj_Entry *obj)
2547 STAILQ_FOREACH(elm, list, link)
2548 if (elm->obj == obj)
2554 objlist_init(Objlist *list)
2560 objlist_push_head(Objlist *list, Obj_Entry *obj)
2564 elm = NEW(Objlist_Entry);
2566 STAILQ_INSERT_HEAD(list, elm, link);
2570 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2574 elm = NEW(Objlist_Entry);
2576 STAILQ_INSERT_TAIL(list, elm, link);
2580 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2582 Objlist_Entry *elm, *listelm;
2584 STAILQ_FOREACH(listelm, list, link) {
2585 if (listelm->obj == listobj)
2588 elm = NEW(Objlist_Entry);
2590 if (listelm != NULL)
2591 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2593 STAILQ_INSERT_TAIL(list, elm, link);
2597 objlist_remove(Objlist *list, Obj_Entry *obj)
2601 if ((elm = objlist_find(list, obj)) != NULL) {
2602 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2608 * Relocate dag rooted in the specified object.
2609 * Returns 0 on success, or -1 on failure.
2613 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2614 int flags, RtldLockState *lockstate)
2620 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2621 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2630 * Relocate single object.
2631 * Returns 0 on success, or -1 on failure.
2634 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2635 int flags, RtldLockState *lockstate)
2640 obj->relocated = true;
2642 dbg("relocating \"%s\"", obj->path);
2644 if (obj->symtab == NULL || obj->strtab == NULL ||
2645 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2646 _rtld_error("%s: Shared object has no run-time symbol table",
2652 /* There are relocations to the write-protected text segment. */
2653 if (mprotect(obj->mapbase, obj->textsize,
2654 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2655 _rtld_error("%s: Cannot write-enable text segment: %s",
2656 obj->path, rtld_strerror(errno));
2661 /* Process the non-PLT non-IFUNC relocations. */
2662 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2665 if (obj->textrel) { /* Re-protected the text segment. */
2666 if (mprotect(obj->mapbase, obj->textsize,
2667 PROT_READ|PROT_EXEC) == -1) {
2668 _rtld_error("%s: Cannot write-protect text segment: %s",
2669 obj->path, rtld_strerror(errno));
2674 /* Set the special PLT or GOT entries. */
2677 /* Process the PLT relocations. */
2678 if (reloc_plt(obj) == -1)
2680 /* Relocate the jump slots if we are doing immediate binding. */
2681 if (obj->bind_now || bind_now)
2682 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2686 * Process the non-PLT IFUNC relocations. The relocations are
2687 * processed in two phases, because IFUNC resolvers may
2688 * reference other symbols, which must be readily processed
2689 * before resolvers are called.
2691 if (obj->non_plt_gnu_ifunc &&
2692 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
2695 if (obj->relro_size > 0) {
2696 if (mprotect(obj->relro_page, obj->relro_size,
2698 _rtld_error("%s: Cannot enforce relro protection: %s",
2699 obj->path, rtld_strerror(errno));
2705 * Set up the magic number and version in the Obj_Entry. These
2706 * were checked in the crt1.o from the original ElfKit, so we
2707 * set them for backward compatibility.
2709 obj->magic = RTLD_MAGIC;
2710 obj->version = RTLD_VERSION;
2716 * Relocate newly-loaded shared objects. The argument is a pointer to
2717 * the Obj_Entry for the first such object. All objects from the first
2718 * to the end of the list of objects are relocated. Returns 0 on success,
2722 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2723 int flags, RtldLockState *lockstate)
2730 TAILQ_FOREACH_FROM(obj, &obj_list, next) {
2733 error = relocate_object(obj, bind_now, rtldobj, flags,
2742 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2743 * referencing STT_GNU_IFUNC symbols is postponed till the other
2744 * relocations are done. The indirect functions specified as
2745 * ifunc are allowed to call other symbols, so we need to have
2746 * objects relocated before asking for resolution from indirects.
2748 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2749 * instead of the usual lazy handling of PLT slots. It is
2750 * consistent with how GNU does it.
2753 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2754 RtldLockState *lockstate)
2756 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2758 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2759 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2765 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2766 RtldLockState *lockstate)
2771 TAILQ_FOREACH_FROM(obj, &obj_list, next) {
2774 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2781 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2782 RtldLockState *lockstate)
2786 STAILQ_FOREACH(elm, list, link) {
2787 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2795 * Cleanup procedure. It will be called (by the atexit mechanism) just
2796 * before the process exits.
2801 RtldLockState lockstate;
2803 wlock_acquire(rtld_bind_lock, &lockstate);
2805 objlist_call_fini(&list_fini, NULL, &lockstate);
2806 /* No need to remove the items from the list, since we are exiting. */
2807 if (!libmap_disable)
2809 lock_release(rtld_bind_lock, &lockstate);
2813 * Iterate over a search path, translate each element, and invoke the
2814 * callback on the result.
2817 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2823 path += strspn(path, ":;");
2824 while (*path != '\0') {
2828 len = strcspn(path, ":;");
2829 trans = lm_findn(NULL, path, len);
2831 res = callback(trans, strlen(trans), arg);
2833 res = callback(path, len, arg);
2839 path += strspn(path, ":;");
2845 struct try_library_args {
2853 try_library_path(const char *dir, size_t dirlen, void *param)
2855 struct try_library_args *arg;
2858 if (*dir == '/' || trust) {
2861 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2864 pathname = arg->buffer;
2865 strncpy(pathname, dir, dirlen);
2866 pathname[dirlen] = '/';
2867 strcpy(pathname + dirlen + 1, arg->name);
2869 dbg(" Trying \"%s\"", pathname);
2870 if (access(pathname, F_OK) == 0) { /* We found it */
2871 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2872 strcpy(pathname, arg->buffer);
2880 search_library_path(const char *name, const char *path)
2883 struct try_library_args arg;
2889 arg.namelen = strlen(name);
2890 arg.buffer = xmalloc(PATH_MAX);
2891 arg.buflen = PATH_MAX;
2893 p = path_enumerate(path, try_library_path, &arg);
2902 * Finds the library with the given name using the directory descriptors
2903 * listed in the LD_LIBRARY_PATH_FDS environment variable.
2905 * Returns a freshly-opened close-on-exec file descriptor for the library,
2906 * or -1 if the library cannot be found.
2909 search_library_pathfds(const char *name, const char *path, int *fdp)
2911 char *envcopy, *fdstr, *found, *last_token;
2915 dbg("%s('%s', '%s', fdp)", __func__, name, path);
2917 /* Don't load from user-specified libdirs into setuid binaries. */
2921 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
2925 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
2926 if (name[0] == '/') {
2927 dbg("Absolute path (%s) passed to %s", name, __func__);
2932 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
2933 * copy of the path, as strtok_r rewrites separator tokens
2937 envcopy = xstrdup(path);
2938 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
2939 fdstr = strtok_r(NULL, ":", &last_token)) {
2940 dirfd = parse_libdir(fdstr);
2943 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
2946 len = strlen(fdstr) + strlen(name) + 3;
2947 found = xmalloc(len);
2948 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
2949 _rtld_error("error generating '%d/%s'",
2953 dbg("open('%s') => %d", found, fd);
2964 dlclose(void *handle)
2967 RtldLockState lockstate;
2969 wlock_acquire(rtld_bind_lock, &lockstate);
2970 root = dlcheck(handle);
2972 lock_release(rtld_bind_lock, &lockstate);
2975 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2978 /* Unreference the object and its dependencies. */
2979 root->dl_refcount--;
2981 if (root->refcount == 1) {
2983 * The object will be no longer referenced, so we must unload it.
2984 * First, call the fini functions.
2986 objlist_call_fini(&list_fini, root, &lockstate);
2990 /* Finish cleaning up the newly-unreferenced objects. */
2991 GDB_STATE(RT_DELETE,&root->linkmap);
2992 unload_object(root);
2993 GDB_STATE(RT_CONSISTENT,NULL);
2997 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2998 lock_release(rtld_bind_lock, &lockstate);
3005 char *msg = error_message;
3006 error_message = NULL;
3011 * This function is deprecated and has no effect.
3014 dllockinit(void *context,
3015 void *(*lock_create)(void *context),
3016 void (*rlock_acquire)(void *lock),
3017 void (*wlock_acquire)(void *lock),
3018 void (*lock_release)(void *lock),
3019 void (*lock_destroy)(void *lock),
3020 void (*context_destroy)(void *context))
3022 static void *cur_context;
3023 static void (*cur_context_destroy)(void *);
3025 /* Just destroy the context from the previous call, if necessary. */
3026 if (cur_context_destroy != NULL)
3027 cur_context_destroy(cur_context);
3028 cur_context = context;
3029 cur_context_destroy = context_destroy;
3033 dlopen(const char *name, int mode)
3036 return (rtld_dlopen(name, -1, mode));
3040 fdlopen(int fd, int mode)
3043 return (rtld_dlopen(NULL, fd, mode));
3047 rtld_dlopen(const char *name, int fd, int mode)
3049 RtldLockState lockstate;
3052 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3053 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3054 if (ld_tracing != NULL) {
3055 rlock_acquire(rtld_bind_lock, &lockstate);
3056 if (sigsetjmp(lockstate.env, 0) != 0)
3057 lock_upgrade(rtld_bind_lock, &lockstate);
3058 environ = (char **)*get_program_var_addr("environ", &lockstate);
3059 lock_release(rtld_bind_lock, &lockstate);
3061 lo_flags = RTLD_LO_DLOPEN;
3062 if (mode & RTLD_NODELETE)
3063 lo_flags |= RTLD_LO_NODELETE;
3064 if (mode & RTLD_NOLOAD)
3065 lo_flags |= RTLD_LO_NOLOAD;
3066 if (ld_tracing != NULL)
3067 lo_flags |= RTLD_LO_TRACE;
3069 return (dlopen_object(name, fd, obj_main, lo_flags,
3070 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3074 dlopen_cleanup(Obj_Entry *obj)
3079 if (obj->refcount == 0)
3084 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3085 int mode, RtldLockState *lockstate)
3087 Obj_Entry *old_obj_tail;
3090 RtldLockState mlockstate;
3093 objlist_init(&initlist);
3095 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3096 wlock_acquire(rtld_bind_lock, &mlockstate);
3097 lockstate = &mlockstate;
3099 GDB_STATE(RT_ADD,NULL);
3101 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
3103 if (name == NULL && fd == -1) {
3107 obj = load_object(name, fd, refobj, lo_flags);
3112 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3113 objlist_push_tail(&list_global, obj);
3114 if (globallist_next(old_obj_tail) != NULL) {
3115 /* We loaded something new. */
3116 assert(globallist_next(old_obj_tail) == obj);
3117 result = load_needed_objects(obj,
3118 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
3122 result = rtld_verify_versions(&obj->dagmembers);
3123 if (result != -1 && ld_tracing)
3125 if (result == -1 || relocate_object_dag(obj,
3126 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3127 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3129 dlopen_cleanup(obj);
3131 } else if (lo_flags & RTLD_LO_EARLY) {
3133 * Do not call the init functions for early loaded
3134 * filtees. The image is still not initialized enough
3137 * Our object is found by the global object list and
3138 * will be ordered among all init calls done right
3139 * before transferring control to main.
3142 /* Make list of init functions to call. */
3143 initlist_add_objects(obj, obj, &initlist);
3146 * Process all no_delete or global objects here, given
3147 * them own DAGs to prevent their dependencies from being
3148 * unloaded. This has to be done after we have loaded all
3149 * of the dependencies, so that we do not miss any.
3155 * Bump the reference counts for objects on this DAG. If
3156 * this is the first dlopen() call for the object that was
3157 * already loaded as a dependency, initialize the dag
3163 if ((lo_flags & RTLD_LO_TRACE) != 0)
3166 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3167 obj->z_nodelete) && !obj->ref_nodel) {
3168 dbg("obj %s nodelete", obj->path);
3170 obj->z_nodelete = obj->ref_nodel = true;
3174 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3176 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3178 if (!(lo_flags & RTLD_LO_EARLY)) {
3179 map_stacks_exec(lockstate);
3182 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3183 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3185 objlist_clear(&initlist);
3186 dlopen_cleanup(obj);
3187 if (lockstate == &mlockstate)
3188 lock_release(rtld_bind_lock, lockstate);
3192 if (!(lo_flags & RTLD_LO_EARLY)) {
3193 /* Call the init functions. */
3194 objlist_call_init(&initlist, lockstate);
3196 objlist_clear(&initlist);
3197 if (lockstate == &mlockstate)
3198 lock_release(rtld_bind_lock, lockstate);
3201 trace_loaded_objects(obj);
3202 if (lockstate == &mlockstate)
3203 lock_release(rtld_bind_lock, lockstate);
3208 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3212 const Obj_Entry *obj, *defobj;
3215 RtldLockState lockstate;
3222 symlook_init(&req, name);
3224 req.flags = flags | SYMLOOK_IN_PLT;
3225 req.lockstate = &lockstate;
3227 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3228 rlock_acquire(rtld_bind_lock, &lockstate);
3229 if (sigsetjmp(lockstate.env, 0) != 0)
3230 lock_upgrade(rtld_bind_lock, &lockstate);
3231 if (handle == NULL || handle == RTLD_NEXT ||
3232 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3234 if ((obj = obj_from_addr(retaddr)) == NULL) {
3235 _rtld_error("Cannot determine caller's shared object");
3236 lock_release(rtld_bind_lock, &lockstate);
3237 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3240 if (handle == NULL) { /* Just the caller's shared object. */
3241 res = symlook_obj(&req, obj);
3244 defobj = req.defobj_out;
3246 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3247 handle == RTLD_SELF) { /* ... caller included */
3248 if (handle == RTLD_NEXT)
3249 obj = globallist_next(obj);
3250 TAILQ_FOREACH_FROM(obj, &obj_list, next) {
3253 res = symlook_obj(&req, obj);
3256 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3258 defobj = req.defobj_out;
3259 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3265 * Search the dynamic linker itself, and possibly resolve the
3266 * symbol from there. This is how the application links to
3267 * dynamic linker services such as dlopen.
3269 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3270 res = symlook_obj(&req, &obj_rtld);
3273 defobj = req.defobj_out;
3277 assert(handle == RTLD_DEFAULT);
3278 res = symlook_default(&req, obj);
3280 defobj = req.defobj_out;
3285 if ((obj = dlcheck(handle)) == NULL) {
3286 lock_release(rtld_bind_lock, &lockstate);
3287 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3291 donelist_init(&donelist);
3292 if (obj->mainprog) {
3293 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3294 res = symlook_global(&req, &donelist);
3297 defobj = req.defobj_out;
3300 * Search the dynamic linker itself, and possibly resolve the
3301 * symbol from there. This is how the application links to
3302 * dynamic linker services such as dlopen.
3304 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3305 res = symlook_obj(&req, &obj_rtld);
3308 defobj = req.defobj_out;
3313 /* Search the whole DAG rooted at the given object. */
3314 res = symlook_list(&req, &obj->dagmembers, &donelist);
3317 defobj = req.defobj_out;
3323 lock_release(rtld_bind_lock, &lockstate);
3326 * The value required by the caller is derived from the value
3327 * of the symbol. this is simply the relocated value of the
3330 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3331 sym = make_function_pointer(def, defobj);
3332 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3333 sym = rtld_resolve_ifunc(defobj, def);
3334 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3335 ti.ti_module = defobj->tlsindex;
3336 ti.ti_offset = def->st_value;
3337 sym = __tls_get_addr(&ti);
3339 sym = defobj->relocbase + def->st_value;
3340 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3344 _rtld_error("Undefined symbol \"%s\"", name);
3345 lock_release(rtld_bind_lock, &lockstate);
3346 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3351 dlsym(void *handle, const char *name)
3353 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3358 dlfunc(void *handle, const char *name)
3365 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3371 dlvsym(void *handle, const char *name, const char *version)
3375 ventry.name = version;
3377 ventry.hash = elf_hash(version);
3379 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3384 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3386 const Obj_Entry *obj;
3387 RtldLockState lockstate;
3389 rlock_acquire(rtld_bind_lock, &lockstate);
3390 obj = obj_from_addr(addr);
3392 _rtld_error("No shared object contains address");
3393 lock_release(rtld_bind_lock, &lockstate);
3396 rtld_fill_dl_phdr_info(obj, phdr_info);
3397 lock_release(rtld_bind_lock, &lockstate);
3402 dladdr(const void *addr, Dl_info *info)
3404 const Obj_Entry *obj;
3407 unsigned long symoffset;
3408 RtldLockState lockstate;
3410 rlock_acquire(rtld_bind_lock, &lockstate);
3411 obj = obj_from_addr(addr);
3413 _rtld_error("No shared object contains address");
3414 lock_release(rtld_bind_lock, &lockstate);
3417 info->dli_fname = obj->path;
3418 info->dli_fbase = obj->mapbase;
3419 info->dli_saddr = (void *)0;
3420 info->dli_sname = NULL;
3423 * Walk the symbol list looking for the symbol whose address is
3424 * closest to the address sent in.
3426 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3427 def = obj->symtab + symoffset;
3430 * For skip the symbol if st_shndx is either SHN_UNDEF or
3433 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3437 * If the symbol is greater than the specified address, or if it
3438 * is further away from addr than the current nearest symbol,
3441 symbol_addr = obj->relocbase + def->st_value;
3442 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3445 /* Update our idea of the nearest symbol. */
3446 info->dli_sname = obj->strtab + def->st_name;
3447 info->dli_saddr = symbol_addr;
3450 if (info->dli_saddr == addr)
3453 lock_release(rtld_bind_lock, &lockstate);
3458 dlinfo(void *handle, int request, void *p)
3460 const Obj_Entry *obj;
3461 RtldLockState lockstate;
3464 rlock_acquire(rtld_bind_lock, &lockstate);
3466 if (handle == NULL || handle == RTLD_SELF) {
3469 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3470 if ((obj = obj_from_addr(retaddr)) == NULL)
3471 _rtld_error("Cannot determine caller's shared object");
3473 obj = dlcheck(handle);
3476 lock_release(rtld_bind_lock, &lockstate);
3482 case RTLD_DI_LINKMAP:
3483 *((struct link_map const **)p) = &obj->linkmap;
3485 case RTLD_DI_ORIGIN:
3486 error = rtld_dirname(obj->path, p);
3489 case RTLD_DI_SERINFOSIZE:
3490 case RTLD_DI_SERINFO:
3491 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3495 _rtld_error("Invalid request %d passed to dlinfo()", request);
3499 lock_release(rtld_bind_lock, &lockstate);
3505 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3508 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3509 phdr_info->dlpi_name = obj->path;
3510 phdr_info->dlpi_phdr = obj->phdr;
3511 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3512 phdr_info->dlpi_tls_modid = obj->tlsindex;
3513 phdr_info->dlpi_tls_data = obj->tlsinit;
3514 phdr_info->dlpi_adds = obj_loads;
3515 phdr_info->dlpi_subs = obj_loads - obj_count;
3519 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3521 struct dl_phdr_info phdr_info;
3522 Obj_Entry *obj, marker;
3523 RtldLockState bind_lockstate, phdr_lockstate;
3526 bzero(&marker, sizeof(marker));
3527 marker.marker = true;
3530 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3531 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3532 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
3533 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
3534 rtld_fill_dl_phdr_info(obj, &phdr_info);
3535 lock_release(rtld_bind_lock, &bind_lockstate);
3537 error = callback(&phdr_info, sizeof phdr_info, param);
3539 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3540 obj = globallist_next(&marker);
3541 TAILQ_REMOVE(&obj_list, &marker, next);
3543 lock_release(rtld_bind_lock, &bind_lockstate);
3544 lock_release(rtld_phdr_lock, &phdr_lockstate);
3550 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3551 lock_release(rtld_bind_lock, &bind_lockstate);
3552 error = callback(&phdr_info, sizeof(phdr_info), param);
3554 lock_release(rtld_phdr_lock, &phdr_lockstate);
3559 fill_search_info(const char *dir, size_t dirlen, void *param)
3561 struct fill_search_info_args *arg;
3565 if (arg->request == RTLD_DI_SERINFOSIZE) {
3566 arg->serinfo->dls_cnt ++;
3567 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3569 struct dl_serpath *s_entry;
3571 s_entry = arg->serpath;
3572 s_entry->dls_name = arg->strspace;
3573 s_entry->dls_flags = arg->flags;
3575 strncpy(arg->strspace, dir, dirlen);
3576 arg->strspace[dirlen] = '\0';
3578 arg->strspace += dirlen + 1;
3586 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3588 struct dl_serinfo _info;
3589 struct fill_search_info_args args;
3591 args.request = RTLD_DI_SERINFOSIZE;
3592 args.serinfo = &_info;
3594 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3597 path_enumerate(obj->rpath, fill_search_info, &args);
3598 path_enumerate(ld_library_path, fill_search_info, &args);
3599 path_enumerate(obj->runpath, fill_search_info, &args);
3600 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3601 if (!obj->z_nodeflib)
3602 path_enumerate(ld_standard_library_path, fill_search_info, &args);
3605 if (request == RTLD_DI_SERINFOSIZE) {
3606 info->dls_size = _info.dls_size;
3607 info->dls_cnt = _info.dls_cnt;
3611 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3612 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3616 args.request = RTLD_DI_SERINFO;
3617 args.serinfo = info;
3618 args.serpath = &info->dls_serpath[0];
3619 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3621 args.flags = LA_SER_RUNPATH;
3622 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3625 args.flags = LA_SER_LIBPATH;
3626 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3629 args.flags = LA_SER_RUNPATH;
3630 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3633 args.flags = LA_SER_CONFIG;
3634 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3638 args.flags = LA_SER_DEFAULT;
3639 if (!obj->z_nodeflib &&
3640 path_enumerate(ld_standard_library_path, fill_search_info, &args) != NULL)
3646 rtld_dirname(const char *path, char *bname)
3650 /* Empty or NULL string gets treated as "." */
3651 if (path == NULL || *path == '\0') {
3657 /* Strip trailing slashes */
3658 endp = path + strlen(path) - 1;
3659 while (endp > path && *endp == '/')
3662 /* Find the start of the dir */
3663 while (endp > path && *endp != '/')
3666 /* Either the dir is "/" or there are no slashes */
3668 bname[0] = *endp == '/' ? '/' : '.';
3674 } while (endp > path && *endp == '/');
3677 if (endp - path + 2 > PATH_MAX)
3679 _rtld_error("Filename is too long: %s", path);
3683 strncpy(bname, path, endp - path + 1);
3684 bname[endp - path + 1] = '\0';
3689 rtld_dirname_abs(const char *path, char *base)
3693 if (realpath(path, base) == NULL)
3695 dbg("%s -> %s", path, base);
3696 last = strrchr(base, '/');
3705 linkmap_add(Obj_Entry *obj)
3707 struct link_map *l = &obj->linkmap;
3708 struct link_map *prev;
3710 obj->linkmap.l_name = obj->path;
3711 obj->linkmap.l_addr = obj->mapbase;
3712 obj->linkmap.l_ld = obj->dynamic;
3714 /* GDB needs load offset on MIPS to use the symbols */
3715 obj->linkmap.l_offs = obj->relocbase;
3718 if (r_debug.r_map == NULL) {
3724 * Scan to the end of the list, but not past the entry for the
3725 * dynamic linker, which we want to keep at the very end.
3727 for (prev = r_debug.r_map;
3728 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3729 prev = prev->l_next)
3732 /* Link in the new entry. */
3734 l->l_next = prev->l_next;
3735 if (l->l_next != NULL)
3736 l->l_next->l_prev = l;
3741 linkmap_delete(Obj_Entry *obj)
3743 struct link_map *l = &obj->linkmap;
3745 if (l->l_prev == NULL) {
3746 if ((r_debug.r_map = l->l_next) != NULL)
3747 l->l_next->l_prev = NULL;
3751 if ((l->l_prev->l_next = l->l_next) != NULL)
3752 l->l_next->l_prev = l->l_prev;
3756 * Function for the debugger to set a breakpoint on to gain control.
3758 * The two parameters allow the debugger to easily find and determine
3759 * what the runtime loader is doing and to whom it is doing it.
3761 * When the loadhook trap is hit (r_debug_state, set at program
3762 * initialization), the arguments can be found on the stack:
3764 * +8 struct link_map *m
3765 * +4 struct r_debug *rd
3769 r_debug_state(struct r_debug* rd, struct link_map *m)
3772 * The following is a hack to force the compiler to emit calls to
3773 * this function, even when optimizing. If the function is empty,
3774 * the compiler is not obliged to emit any code for calls to it,
3775 * even when marked __noinline. However, gdb depends on those
3778 __compiler_membar();
3782 * A function called after init routines have completed. This can be used to
3783 * break before a program's entry routine is called, and can be used when
3784 * main is not available in the symbol table.
3787 _r_debug_postinit(struct link_map *m)
3790 /* See r_debug_state(). */
3791 __compiler_membar();
3795 * Get address of the pointer variable in the main program.
3796 * Prefer non-weak symbol over the weak one.
3798 static const void **
3799 get_program_var_addr(const char *name, RtldLockState *lockstate)
3804 symlook_init(&req, name);
3805 req.lockstate = lockstate;
3806 donelist_init(&donelist);
3807 if (symlook_global(&req, &donelist) != 0)
3809 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3810 return ((const void **)make_function_pointer(req.sym_out,
3812 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3813 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3815 return ((const void **)(req.defobj_out->relocbase +
3816 req.sym_out->st_value));
3820 * Set a pointer variable in the main program to the given value. This
3821 * is used to set key variables such as "environ" before any of the
3822 * init functions are called.
3825 set_program_var(const char *name, const void *value)
3829 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3830 dbg("\"%s\": *%p <-- %p", name, addr, value);
3836 * Search the global objects, including dependencies and main object,
3837 * for the given symbol.
3840 symlook_global(SymLook *req, DoneList *donelist)
3843 const Objlist_Entry *elm;
3846 symlook_init_from_req(&req1, req);
3848 /* Search all objects loaded at program start up. */
3849 if (req->defobj_out == NULL ||
3850 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3851 res = symlook_list(&req1, &list_main, donelist);
3852 if (res == 0 && (req->defobj_out == NULL ||
3853 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3854 req->sym_out = req1.sym_out;
3855 req->defobj_out = req1.defobj_out;
3856 assert(req->defobj_out != NULL);
3860 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3861 STAILQ_FOREACH(elm, &list_global, link) {
3862 if (req->defobj_out != NULL &&
3863 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3865 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3866 if (res == 0 && (req->defobj_out == NULL ||
3867 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3868 req->sym_out = req1.sym_out;
3869 req->defobj_out = req1.defobj_out;
3870 assert(req->defobj_out != NULL);
3874 return (req->sym_out != NULL ? 0 : ESRCH);
3878 * Given a symbol name in a referencing object, find the corresponding
3879 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3880 * no definition was found. Returns a pointer to the Obj_Entry of the
3881 * defining object via the reference parameter DEFOBJ_OUT.
3884 symlook_default(SymLook *req, const Obj_Entry *refobj)
3887 const Objlist_Entry *elm;
3891 donelist_init(&donelist);
3892 symlook_init_from_req(&req1, req);
3894 /* Look first in the referencing object if linked symbolically. */
3895 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3896 res = symlook_obj(&req1, refobj);
3898 req->sym_out = req1.sym_out;
3899 req->defobj_out = req1.defobj_out;
3900 assert(req->defobj_out != NULL);
3904 symlook_global(req, &donelist);
3906 /* Search all dlopened DAGs containing the referencing object. */
3907 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3908 if (req->sym_out != NULL &&
3909 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3911 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3912 if (res == 0 && (req->sym_out == NULL ||
3913 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3914 req->sym_out = req1.sym_out;
3915 req->defobj_out = req1.defobj_out;
3916 assert(req->defobj_out != NULL);
3921 * Search the dynamic linker itself, and possibly resolve the
3922 * symbol from there. This is how the application links to
3923 * dynamic linker services such as dlopen.
3925 if (req->sym_out == NULL ||
3926 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3927 res = symlook_obj(&req1, &obj_rtld);
3929 req->sym_out = req1.sym_out;
3930 req->defobj_out = req1.defobj_out;
3931 assert(req->defobj_out != NULL);
3935 return (req->sym_out != NULL ? 0 : ESRCH);
3939 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3942 const Obj_Entry *defobj;
3943 const Objlist_Entry *elm;
3949 STAILQ_FOREACH(elm, objlist, link) {
3950 if (donelist_check(dlp, elm->obj))
3952 symlook_init_from_req(&req1, req);
3953 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3954 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3956 defobj = req1.defobj_out;
3957 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3964 req->defobj_out = defobj;
3971 * Search the chain of DAGS cointed to by the given Needed_Entry
3972 * for a symbol of the given name. Each DAG is scanned completely
3973 * before advancing to the next one. Returns a pointer to the symbol,
3974 * or NULL if no definition was found.
3977 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3980 const Needed_Entry *n;
3981 const Obj_Entry *defobj;
3987 symlook_init_from_req(&req1, req);
3988 for (n = needed; n != NULL; n = n->next) {
3989 if (n->obj == NULL ||
3990 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3992 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3994 defobj = req1.defobj_out;
3995 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4001 req->defobj_out = defobj;
4008 * Search the symbol table of a single shared object for a symbol of
4009 * the given name and version, if requested. Returns a pointer to the
4010 * symbol, or NULL if no definition was found. If the object is
4011 * filter, return filtered symbol from filtee.
4013 * The symbol's hash value is passed in for efficiency reasons; that
4014 * eliminates many recomputations of the hash value.
4017 symlook_obj(SymLook *req, const Obj_Entry *obj)
4021 int flags, res, mres;
4024 * If there is at least one valid hash at this point, we prefer to
4025 * use the faster GNU version if available.
4027 if (obj->valid_hash_gnu)
4028 mres = symlook_obj1_gnu(req, obj);
4029 else if (obj->valid_hash_sysv)
4030 mres = symlook_obj1_sysv(req, obj);
4035 if (obj->needed_filtees != NULL) {
4036 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4037 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4038 donelist_init(&donelist);
4039 symlook_init_from_req(&req1, req);
4040 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
4042 req->sym_out = req1.sym_out;
4043 req->defobj_out = req1.defobj_out;
4047 if (obj->needed_aux_filtees != NULL) {
4048 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4049 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4050 donelist_init(&donelist);
4051 symlook_init_from_req(&req1, req);
4052 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
4054 req->sym_out = req1.sym_out;
4055 req->defobj_out = req1.defobj_out;
4063 /* Symbol match routine common to both hash functions */
4065 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4066 const unsigned long symnum)
4069 const Elf_Sym *symp;
4072 symp = obj->symtab + symnum;
4073 strp = obj->strtab + symp->st_name;
4075 switch (ELF_ST_TYPE(symp->st_info)) {
4081 if (symp->st_value == 0)
4085 if (symp->st_shndx != SHN_UNDEF)
4088 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4089 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4096 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4099 if (req->ventry == NULL) {
4100 if (obj->versyms != NULL) {
4101 verndx = VER_NDX(obj->versyms[symnum]);
4102 if (verndx > obj->vernum) {
4104 "%s: symbol %s references wrong version %d",
4105 obj->path, obj->strtab + symnum, verndx);
4109 * If we are not called from dlsym (i.e. this
4110 * is a normal relocation from unversioned
4111 * binary), accept the symbol immediately if
4112 * it happens to have first version after this
4113 * shared object became versioned. Otherwise,
4114 * if symbol is versioned and not hidden,
4115 * remember it. If it is the only symbol with
4116 * this name exported by the shared object, it
4117 * will be returned as a match by the calling
4118 * function. If symbol is global (verndx < 2)
4119 * accept it unconditionally.
4121 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4122 verndx == VER_NDX_GIVEN) {
4123 result->sym_out = symp;
4126 else if (verndx >= VER_NDX_GIVEN) {
4127 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4129 if (result->vsymp == NULL)
4130 result->vsymp = symp;
4136 result->sym_out = symp;
4139 if (obj->versyms == NULL) {
4140 if (object_match_name(obj, req->ventry->name)) {
4141 _rtld_error("%s: object %s should provide version %s "
4142 "for symbol %s", obj_rtld.path, obj->path,
4143 req->ventry->name, obj->strtab + symnum);
4147 verndx = VER_NDX(obj->versyms[symnum]);
4148 if (verndx > obj->vernum) {
4149 _rtld_error("%s: symbol %s references wrong version %d",
4150 obj->path, obj->strtab + symnum, verndx);
4153 if (obj->vertab[verndx].hash != req->ventry->hash ||
4154 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4156 * Version does not match. Look if this is a
4157 * global symbol and if it is not hidden. If
4158 * global symbol (verndx < 2) is available,
4159 * use it. Do not return symbol if we are
4160 * called by dlvsym, because dlvsym looks for
4161 * a specific version and default one is not
4162 * what dlvsym wants.
4164 if ((req->flags & SYMLOOK_DLSYM) ||
4165 (verndx >= VER_NDX_GIVEN) ||
4166 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4170 result->sym_out = symp;
4175 * Search for symbol using SysV hash function.
4176 * obj->buckets is known not to be NULL at this point; the test for this was
4177 * performed with the obj->valid_hash_sysv assignment.
4180 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4182 unsigned long symnum;
4183 Sym_Match_Result matchres;
4185 matchres.sym_out = NULL;
4186 matchres.vsymp = NULL;
4187 matchres.vcount = 0;
4189 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4190 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4191 if (symnum >= obj->nchains)
4192 return (ESRCH); /* Bad object */
4194 if (matched_symbol(req, obj, &matchres, symnum)) {
4195 req->sym_out = matchres.sym_out;
4196 req->defobj_out = obj;
4200 if (matchres.vcount == 1) {
4201 req->sym_out = matchres.vsymp;
4202 req->defobj_out = obj;
4208 /* Search for symbol using GNU hash function */
4210 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4212 Elf_Addr bloom_word;
4213 const Elf32_Word *hashval;
4215 Sym_Match_Result matchres;
4216 unsigned int h1, h2;
4217 unsigned long symnum;
4219 matchres.sym_out = NULL;
4220 matchres.vsymp = NULL;
4221 matchres.vcount = 0;
4223 /* Pick right bitmask word from Bloom filter array */
4224 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4225 obj->maskwords_bm_gnu];
4227 /* Calculate modulus word size of gnu hash and its derivative */
4228 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4229 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4231 /* Filter out the "definitely not in set" queries */
4232 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4235 /* Locate hash chain and corresponding value element*/
4236 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4239 hashval = &obj->chain_zero_gnu[bucket];
4241 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4242 symnum = hashval - obj->chain_zero_gnu;
4243 if (matched_symbol(req, obj, &matchres, symnum)) {
4244 req->sym_out = matchres.sym_out;
4245 req->defobj_out = obj;
4249 } while ((*hashval++ & 1) == 0);
4250 if (matchres.vcount == 1) {
4251 req->sym_out = matchres.vsymp;
4252 req->defobj_out = obj;
4259 trace_loaded_objects(Obj_Entry *obj)
4261 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4264 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL)
4267 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL)
4268 fmt1 = "\t%o => %p (%x)\n";
4270 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL)
4271 fmt2 = "\t%o (%x)\n";
4273 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL"));
4275 TAILQ_FOREACH_FROM(obj, &obj_list, next) {
4276 Needed_Entry *needed;
4282 if (list_containers && obj->needed != NULL)
4283 rtld_printf("%s:\n", obj->path);
4284 for (needed = obj->needed; needed; needed = needed->next) {
4285 if (needed->obj != NULL) {
4286 if (needed->obj->traced && !list_containers)
4288 needed->obj->traced = true;
4289 path = needed->obj->path;
4293 name = (char *)obj->strtab + needed->name;
4294 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4296 fmt = is_lib ? fmt1 : fmt2;
4297 while ((c = *fmt++) != '\0') {
4323 rtld_putstr(main_local);
4326 rtld_putstr(obj_main->path);
4333 rtld_printf("%d", sodp->sod_major);
4336 rtld_printf("%d", sodp->sod_minor);
4343 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4356 * Unload a dlopened object and its dependencies from memory and from
4357 * our data structures. It is assumed that the DAG rooted in the
4358 * object has already been unreferenced, and that the object has a
4359 * reference count of 0.
4362 unload_object(Obj_Entry *root)
4364 Obj_Entry *obj, *obj1;
4366 assert(root->refcount == 0);
4369 * Pass over the DAG removing unreferenced objects from
4370 * appropriate lists.
4372 unlink_object(root);
4374 /* Unmap all objects that are no longer referenced. */
4375 TAILQ_FOREACH_SAFE(obj, &obj_list, next, obj1) {
4376 if (obj->marker || obj->refcount != 0)
4378 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
4379 obj->mapsize, 0, obj->path);
4380 dbg("unloading \"%s\"", obj->path);
4381 unload_filtees(root);
4382 munmap(obj->mapbase, obj->mapsize);
4383 linkmap_delete(obj);
4384 TAILQ_REMOVE(&obj_list, obj, next);
4391 unlink_object(Obj_Entry *root)
4395 if (root->refcount == 0) {
4396 /* Remove the object from the RTLD_GLOBAL list. */
4397 objlist_remove(&list_global, root);
4399 /* Remove the object from all objects' DAG lists. */
4400 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4401 objlist_remove(&elm->obj->dldags, root);
4402 if (elm->obj != root)
4403 unlink_object(elm->obj);
4409 ref_dag(Obj_Entry *root)
4413 assert(root->dag_inited);
4414 STAILQ_FOREACH(elm, &root->dagmembers, link)
4415 elm->obj->refcount++;
4419 unref_dag(Obj_Entry *root)
4423 assert(root->dag_inited);
4424 STAILQ_FOREACH(elm, &root->dagmembers, link)
4425 elm->obj->refcount--;
4429 * Common code for MD __tls_get_addr().
4431 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4433 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4435 Elf_Addr *newdtv, *dtv;
4436 RtldLockState lockstate;
4440 /* Check dtv generation in case new modules have arrived */
4441 if (dtv[0] != tls_dtv_generation) {
4442 wlock_acquire(rtld_bind_lock, &lockstate);
4443 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4445 if (to_copy > tls_max_index)
4446 to_copy = tls_max_index;
4447 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4448 newdtv[0] = tls_dtv_generation;
4449 newdtv[1] = tls_max_index;
4451 lock_release(rtld_bind_lock, &lockstate);
4452 dtv = *dtvp = newdtv;
4455 /* Dynamically allocate module TLS if necessary */
4456 if (dtv[index + 1] == 0) {
4457 /* Signal safe, wlock will block out signals. */
4458 wlock_acquire(rtld_bind_lock, &lockstate);
4459 if (!dtv[index + 1])
4460 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4461 lock_release(rtld_bind_lock, &lockstate);
4463 return ((void *)(dtv[index + 1] + offset));
4467 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4472 /* Check dtv generation in case new modules have arrived */
4473 if (__predict_true(dtv[0] == tls_dtv_generation &&
4474 dtv[index + 1] != 0))
4475 return ((void *)(dtv[index + 1] + offset));
4476 return (tls_get_addr_slow(dtvp, index, offset));
4479 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
4480 defined(__powerpc__) || defined(__riscv__)
4483 * Allocate Static TLS using the Variant I method.
4486 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4495 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4498 assert(tcbsize >= TLS_TCB_SIZE);
4499 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4500 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4502 if (oldtcb != NULL) {
4503 memcpy(tls, oldtcb, tls_static_space);
4506 /* Adjust the DTV. */
4508 for (i = 0; i < dtv[1]; i++) {
4509 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4510 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4511 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4515 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4517 dtv[0] = tls_dtv_generation;
4518 dtv[1] = tls_max_index;
4520 for (obj = globallist_curr(objs); obj != NULL;
4521 obj = globallist_next(obj)) {
4522 if (obj->tlsoffset > 0) {
4523 addr = (Elf_Addr)tls + obj->tlsoffset;
4524 if (obj->tlsinitsize > 0)
4525 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4526 if (obj->tlssize > obj->tlsinitsize)
4527 memset((void*) (addr + obj->tlsinitsize), 0,
4528 obj->tlssize - obj->tlsinitsize);
4529 dtv[obj->tlsindex + 1] = addr;
4538 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4541 Elf_Addr tlsstart, tlsend;
4544 assert(tcbsize >= TLS_TCB_SIZE);
4546 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4547 tlsend = tlsstart + tls_static_space;
4549 dtv = *(Elf_Addr **)tlsstart;
4551 for (i = 0; i < dtvsize; i++) {
4552 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4553 free((void*)dtv[i+2]);
4562 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4565 * Allocate Static TLS using the Variant II method.
4568 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4571 size_t size, ralign;
4573 Elf_Addr *dtv, *olddtv;
4574 Elf_Addr segbase, oldsegbase, addr;
4578 if (tls_static_max_align > ralign)
4579 ralign = tls_static_max_align;
4580 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4582 assert(tcbsize >= 2*sizeof(Elf_Addr));
4583 tls = malloc_aligned(size, ralign);
4584 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4586 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4587 ((Elf_Addr*)segbase)[0] = segbase;
4588 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4590 dtv[0] = tls_dtv_generation;
4591 dtv[1] = tls_max_index;
4595 * Copy the static TLS block over whole.
4597 oldsegbase = (Elf_Addr) oldtls;
4598 memcpy((void *)(segbase - tls_static_space),
4599 (const void *)(oldsegbase - tls_static_space),
4603 * If any dynamic TLS blocks have been created tls_get_addr(),
4606 olddtv = ((Elf_Addr**)oldsegbase)[1];
4607 for (i = 0; i < olddtv[1]; i++) {
4608 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4609 dtv[i+2] = olddtv[i+2];
4615 * We assume that this block was the one we created with
4616 * allocate_initial_tls().
4618 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4621 TAILQ_FOREACH_FROM(obj, &obj_list, next) {
4622 if (obj->marker || obj->tlsoffset == 0)
4624 addr = segbase - obj->tlsoffset;
4625 memset((void*) (addr + obj->tlsinitsize),
4626 0, obj->tlssize - obj->tlsinitsize);
4628 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4629 dtv[obj->tlsindex + 1] = addr;
4633 return (void*) segbase;
4637 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4640 size_t size, ralign;
4642 Elf_Addr tlsstart, tlsend;
4645 * Figure out the size of the initial TLS block so that we can
4646 * find stuff which ___tls_get_addr() allocated dynamically.
4649 if (tls_static_max_align > ralign)
4650 ralign = tls_static_max_align;
4651 size = round(tls_static_space, ralign);
4653 dtv = ((Elf_Addr**)tls)[1];
4655 tlsend = (Elf_Addr) tls;
4656 tlsstart = tlsend - size;
4657 for (i = 0; i < dtvsize; i++) {
4658 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4659 free_aligned((void *)dtv[i + 2]);
4663 free_aligned((void *)tlsstart);
4670 * Allocate TLS block for module with given index.
4673 allocate_module_tls(int index)
4678 TAILQ_FOREACH(obj, &obj_list, next) {
4681 if (obj->tlsindex == index)
4685 _rtld_error("Can't find module with TLS index %d", index);
4689 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4690 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4691 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4697 allocate_tls_offset(Obj_Entry *obj)
4704 if (obj->tlssize == 0) {
4705 obj->tls_done = true;
4709 if (tls_last_offset == 0)
4710 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4712 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4713 obj->tlssize, obj->tlsalign);
4716 * If we have already fixed the size of the static TLS block, we
4717 * must stay within that size. When allocating the static TLS, we
4718 * leave a small amount of space spare to be used for dynamically
4719 * loading modules which use static TLS.
4721 if (tls_static_space != 0) {
4722 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4724 } else if (obj->tlsalign > tls_static_max_align) {
4725 tls_static_max_align = obj->tlsalign;
4728 tls_last_offset = obj->tlsoffset = off;
4729 tls_last_size = obj->tlssize;
4730 obj->tls_done = true;
4736 free_tls_offset(Obj_Entry *obj)
4740 * If we were the last thing to allocate out of the static TLS
4741 * block, we give our space back to the 'allocator'. This is a
4742 * simplistic workaround to allow libGL.so.1 to be loaded and
4743 * unloaded multiple times.
4745 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4746 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4747 tls_last_offset -= obj->tlssize;
4753 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4756 RtldLockState lockstate;
4758 wlock_acquire(rtld_bind_lock, &lockstate);
4759 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
4761 lock_release(rtld_bind_lock, &lockstate);
4766 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4768 RtldLockState lockstate;
4770 wlock_acquire(rtld_bind_lock, &lockstate);
4771 free_tls(tcb, tcbsize, tcbalign);
4772 lock_release(rtld_bind_lock, &lockstate);
4776 object_add_name(Obj_Entry *obj, const char *name)
4782 entry = malloc(sizeof(Name_Entry) + len);
4784 if (entry != NULL) {
4785 strcpy(entry->name, name);
4786 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4791 object_match_name(const Obj_Entry *obj, const char *name)
4795 STAILQ_FOREACH(entry, &obj->names, link) {
4796 if (strcmp(name, entry->name) == 0)
4803 locate_dependency(const Obj_Entry *obj, const char *name)
4805 const Objlist_Entry *entry;
4806 const Needed_Entry *needed;
4808 STAILQ_FOREACH(entry, &list_main, link) {
4809 if (object_match_name(entry->obj, name))
4813 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4814 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4815 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4817 * If there is DT_NEEDED for the name we are looking for,
4818 * we are all set. Note that object might not be found if
4819 * dependency was not loaded yet, so the function can
4820 * return NULL here. This is expected and handled
4821 * properly by the caller.
4823 return (needed->obj);
4826 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4832 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4833 const Elf_Vernaux *vna)
4835 const Elf_Verdef *vd;
4836 const char *vername;
4838 vername = refobj->strtab + vna->vna_name;
4839 vd = depobj->verdef;
4841 _rtld_error("%s: version %s required by %s not defined",
4842 depobj->path, vername, refobj->path);
4846 if (vd->vd_version != VER_DEF_CURRENT) {
4847 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4848 depobj->path, vd->vd_version);
4851 if (vna->vna_hash == vd->vd_hash) {
4852 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4853 ((char *)vd + vd->vd_aux);
4854 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4857 if (vd->vd_next == 0)
4859 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4861 if (vna->vna_flags & VER_FLG_WEAK)
4863 _rtld_error("%s: version %s required by %s not found",
4864 depobj->path, vername, refobj->path);
4869 rtld_verify_object_versions(Obj_Entry *obj)
4871 const Elf_Verneed *vn;
4872 const Elf_Verdef *vd;
4873 const Elf_Verdaux *vda;
4874 const Elf_Vernaux *vna;
4875 const Obj_Entry *depobj;
4876 int maxvernum, vernum;
4878 if (obj->ver_checked)
4880 obj->ver_checked = true;
4884 * Walk over defined and required version records and figure out
4885 * max index used by any of them. Do very basic sanity checking
4889 while (vn != NULL) {
4890 if (vn->vn_version != VER_NEED_CURRENT) {
4891 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4892 obj->path, vn->vn_version);
4895 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4897 vernum = VER_NEED_IDX(vna->vna_other);
4898 if (vernum > maxvernum)
4900 if (vna->vna_next == 0)
4902 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4904 if (vn->vn_next == 0)
4906 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4910 while (vd != NULL) {
4911 if (vd->vd_version != VER_DEF_CURRENT) {
4912 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4913 obj->path, vd->vd_version);
4916 vernum = VER_DEF_IDX(vd->vd_ndx);
4917 if (vernum > maxvernum)
4919 if (vd->vd_next == 0)
4921 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4928 * Store version information in array indexable by version index.
4929 * Verify that object version requirements are satisfied along the
4932 obj->vernum = maxvernum + 1;
4933 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4936 while (vd != NULL) {
4937 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4938 vernum = VER_DEF_IDX(vd->vd_ndx);
4939 assert(vernum <= maxvernum);
4940 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4941 obj->vertab[vernum].hash = vd->vd_hash;
4942 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4943 obj->vertab[vernum].file = NULL;
4944 obj->vertab[vernum].flags = 0;
4946 if (vd->vd_next == 0)
4948 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4952 while (vn != NULL) {
4953 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4956 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4958 if (check_object_provided_version(obj, depobj, vna))
4960 vernum = VER_NEED_IDX(vna->vna_other);
4961 assert(vernum <= maxvernum);
4962 obj->vertab[vernum].hash = vna->vna_hash;
4963 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4964 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4965 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4966 VER_INFO_HIDDEN : 0;
4967 if (vna->vna_next == 0)
4969 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4971 if (vn->vn_next == 0)
4973 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4979 rtld_verify_versions(const Objlist *objlist)
4981 Objlist_Entry *entry;
4985 STAILQ_FOREACH(entry, objlist, link) {
4987 * Skip dummy objects or objects that have their version requirements
4990 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4992 if (rtld_verify_object_versions(entry->obj) == -1) {
4994 if (ld_tracing == NULL)
4998 if (rc == 0 || ld_tracing != NULL)
4999 rc = rtld_verify_object_versions(&obj_rtld);
5004 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
5009 vernum = VER_NDX(obj->versyms[symnum]);
5010 if (vernum >= obj->vernum) {
5011 _rtld_error("%s: symbol %s has wrong verneed value %d",
5012 obj->path, obj->strtab + symnum, vernum);
5013 } else if (obj->vertab[vernum].hash != 0) {
5014 return &obj->vertab[vernum];
5021 _rtld_get_stack_prot(void)
5024 return (stack_prot);
5028 _rtld_is_dlopened(void *arg)
5031 RtldLockState lockstate;
5034 rlock_acquire(rtld_bind_lock, &lockstate);
5037 obj = obj_from_addr(arg);
5039 _rtld_error("No shared object contains address");
5040 lock_release(rtld_bind_lock, &lockstate);
5043 res = obj->dlopened ? 1 : 0;
5044 lock_release(rtld_bind_lock, &lockstate);
5049 map_stacks_exec(RtldLockState *lockstate)
5051 void (*thr_map_stacks_exec)(void);
5053 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
5055 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
5056 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
5057 if (thr_map_stacks_exec != NULL) {
5058 stack_prot |= PROT_EXEC;
5059 thr_map_stacks_exec();
5064 symlook_init(SymLook *dst, const char *name)
5067 bzero(dst, sizeof(*dst));
5069 dst->hash = elf_hash(name);
5070 dst->hash_gnu = gnu_hash(name);
5074 symlook_init_from_req(SymLook *dst, const SymLook *src)
5077 dst->name = src->name;
5078 dst->hash = src->hash;
5079 dst->hash_gnu = src->hash_gnu;
5080 dst->ventry = src->ventry;
5081 dst->flags = src->flags;
5082 dst->defobj_out = NULL;
5083 dst->sym_out = NULL;
5084 dst->lockstate = src->lockstate;
5089 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
5092 parse_libdir(const char *str)
5094 static const int RADIX = 10; /* XXXJA: possibly support hex? */
5101 for (c = *str; c != '\0'; c = *++str) {
5102 if (c < '0' || c > '9')
5109 /* Make sure we actually parsed something. */
5111 _rtld_error("failed to parse directory FD from '%s'", str);
5118 * Overrides for libc_pic-provided functions.
5122 __getosreldate(void)
5132 oid[1] = KERN_OSRELDATE;
5134 len = sizeof(osrel);
5135 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5136 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5148 void (*__cleanup)(void);
5149 int __isthreaded = 0;
5150 int _thread_autoinit_dummy_decl = 1;
5153 * No unresolved symbols for rtld.
5156 __pthread_cxa_finalize(struct dl_phdr_info *a)
5161 __stack_chk_fail(void)
5164 _rtld_error("stack overflow detected; terminated");
5167 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
5173 _rtld_error("buffer overflow detected; terminated");
5178 rtld_strerror(int errnum)
5181 if (errnum < 0 || errnum >= sys_nerr)
5182 return ("Unknown error");
5183 return (sys_errlist[errnum]);