2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * Copyright 2009-2012 Konstantin Belousov <kib@FreeBSD.ORG>.
5 * Copyright 2012 John Marino <draco@marino.st>.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 * Dynamic linker for ELF.
34 * John Polstra <jdp@polstra.com>.
38 #error "GCC is needed to compile this file"
41 #include <sys/param.h>
42 #include <sys/mount.h>
45 #include <sys/sysctl.h>
47 #include <sys/utsname.h>
48 #include <sys/ktrace.h>
64 #include "rtld_printf.h"
68 #define PATH_RTLD "/libexec/ld-elf.so.1"
70 #define PATH_RTLD "/libexec/ld-elf32.so.1"
74 typedef void (*func_ptr_type)();
75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
78 * Function declarations.
80 static const char *basename(const char *);
81 static void die(void) __dead2;
82 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
83 const Elf_Dyn **, const Elf_Dyn **);
84 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
86 static void digest_dynamic(Obj_Entry *, int);
87 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
88 static Obj_Entry *dlcheck(void *);
89 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
90 int lo_flags, int mode, RtldLockState *lockstate);
91 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
92 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
93 static bool donelist_check(DoneList *, const Obj_Entry *);
94 static void errmsg_restore(char *);
95 static char *errmsg_save(void);
96 static void *fill_search_info(const char *, size_t, void *);
97 static char *find_library(const char *, const Obj_Entry *);
98 static const char *gethints(bool);
99 static void init_dag(Obj_Entry *);
100 static void init_pagesizes(Elf_Auxinfo **aux_info);
101 static void init_rtld(caddr_t, Elf_Auxinfo **);
102 static void initlist_add_neededs(Needed_Entry *, Objlist *);
103 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
104 static void linkmap_add(Obj_Entry *);
105 static void linkmap_delete(Obj_Entry *);
106 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
107 static void unload_filtees(Obj_Entry *);
108 static int load_needed_objects(Obj_Entry *, int);
109 static int load_preload_objects(void);
110 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
111 static void map_stacks_exec(RtldLockState *);
112 static Obj_Entry *obj_from_addr(const void *);
113 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
114 static void objlist_call_init(Objlist *, RtldLockState *);
115 static void objlist_clear(Objlist *);
116 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
117 static void objlist_init(Objlist *);
118 static void objlist_push_head(Objlist *, Obj_Entry *);
119 static void objlist_push_tail(Objlist *, Obj_Entry *);
120 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
121 static void objlist_remove(Objlist *, Obj_Entry *);
122 static void *path_enumerate(const char *, path_enum_proc, void *);
123 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
124 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
125 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
126 int flags, RtldLockState *lockstate);
127 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
129 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
130 int flags, RtldLockState *lockstate);
131 static int rtld_dirname(const char *, char *);
132 static int rtld_dirname_abs(const char *, char *);
133 static void *rtld_dlopen(const char *name, int fd, int mode);
134 static void rtld_exit(void);
135 static char *search_library_path(const char *, const char *);
136 static const void **get_program_var_addr(const char *, RtldLockState *);
137 static void set_program_var(const char *, const void *);
138 static int symlook_default(SymLook *, const Obj_Entry *refobj);
139 static int symlook_global(SymLook *, DoneList *);
140 static void symlook_init_from_req(SymLook *, const SymLook *);
141 static int symlook_list(SymLook *, const Objlist *, DoneList *);
142 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
143 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
144 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
145 static void trace_loaded_objects(Obj_Entry *);
146 static void unlink_object(Obj_Entry *);
147 static void unload_object(Obj_Entry *);
148 static void unref_dag(Obj_Entry *);
149 static void ref_dag(Obj_Entry *);
150 static char *origin_subst_one(char *, const char *, const char *, bool);
151 static char *origin_subst(char *, const char *);
152 static void preinit_main(void);
153 static int rtld_verify_versions(const Objlist *);
154 static int rtld_verify_object_versions(Obj_Entry *);
155 static void object_add_name(Obj_Entry *, const char *);
156 static int object_match_name(const Obj_Entry *, const char *);
157 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
158 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
159 struct dl_phdr_info *phdr_info);
160 static uint32_t gnu_hash(const char *);
161 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
162 const unsigned long);
164 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
165 void _r_debug_postinit(struct link_map *) __noinline __exported;
170 static char *error_message; /* Message for dlerror(), or NULL */
171 struct r_debug r_debug __exported; /* for GDB; */
172 static bool libmap_disable; /* Disable libmap */
173 static bool ld_loadfltr; /* Immediate filters processing */
174 static char *libmap_override; /* Maps to use in addition to libmap.conf */
175 static bool trust; /* False for setuid and setgid programs */
176 static bool dangerous_ld_env; /* True if environment variables have been
177 used to affect the libraries loaded */
178 static char *ld_bind_now; /* Environment variable for immediate binding */
179 static char *ld_debug; /* Environment variable for debugging */
180 static char *ld_library_path; /* Environment variable for search path */
181 static char *ld_preload; /* Environment variable for libraries to
183 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
184 static char *ld_tracing; /* Called from ldd to print libs */
185 static char *ld_utrace; /* Use utrace() to log events. */
186 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
187 static Obj_Entry **obj_tail; /* Link field of last object in list */
188 static Obj_Entry *obj_main; /* The main program shared object */
189 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
190 static unsigned int obj_count; /* Number of objects in obj_list */
191 static unsigned int obj_loads; /* Number of objects in obj_list */
193 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
194 STAILQ_HEAD_INITIALIZER(list_global);
195 static Objlist list_main = /* Objects loaded at program startup */
196 STAILQ_HEAD_INITIALIZER(list_main);
197 static Objlist list_fini = /* Objects needing fini() calls */
198 STAILQ_HEAD_INITIALIZER(list_fini);
200 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
202 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
204 extern Elf_Dyn _DYNAMIC;
205 #pragma weak _DYNAMIC
206 #ifndef RTLD_IS_DYNAMIC
207 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
210 int dlclose(void *) __exported;
211 char *dlerror(void) __exported;
212 void *dlopen(const char *, int) __exported;
213 void *fdlopen(int, int) __exported;
214 void *dlsym(void *, const char *) __exported;
215 dlfunc_t dlfunc(void *, const char *) __exported;
216 void *dlvsym(void *, const char *, const char *) __exported;
217 int dladdr(const void *, Dl_info *) __exported;
218 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
219 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
220 int dlinfo(void *, int , void *) __exported;
221 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
222 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
223 int _rtld_get_stack_prot(void) __exported;
224 int _rtld_is_dlopened(void *) __exported;
225 void _rtld_error(const char *, ...) __exported;
227 int npagesizes, osreldate;
230 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
232 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
233 static int max_stack_flags;
236 * Global declarations normally provided by crt1. The dynamic linker is
237 * not built with crt1, so we have to provide them ourselves.
243 * Used to pass argc, argv to init functions.
249 * Globals to control TLS allocation.
251 size_t tls_last_offset; /* Static TLS offset of last module */
252 size_t tls_last_size; /* Static TLS size of last module */
253 size_t tls_static_space; /* Static TLS space allocated */
254 size_t tls_static_max_align;
255 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
256 int tls_max_index = 1; /* Largest module index allocated */
258 bool ld_library_path_rpath = false;
261 * Fill in a DoneList with an allocation large enough to hold all of
262 * the currently-loaded objects. Keep this as a macro since it calls
263 * alloca and we want that to occur within the scope of the caller.
265 #define donelist_init(dlp) \
266 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
267 assert((dlp)->objs != NULL), \
268 (dlp)->num_alloc = obj_count, \
271 #define UTRACE_DLOPEN_START 1
272 #define UTRACE_DLOPEN_STOP 2
273 #define UTRACE_DLCLOSE_START 3
274 #define UTRACE_DLCLOSE_STOP 4
275 #define UTRACE_LOAD_OBJECT 5
276 #define UTRACE_UNLOAD_OBJECT 6
277 #define UTRACE_ADD_RUNDEP 7
278 #define UTRACE_PRELOAD_FINISHED 8
279 #define UTRACE_INIT_CALL 9
280 #define UTRACE_FINI_CALL 10
283 char sig[4]; /* 'RTLD' */
286 void *mapbase; /* Used for 'parent' and 'init/fini' */
288 int refcnt; /* Used for 'mode' */
289 char name[MAXPATHLEN];
292 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
293 if (ld_utrace != NULL) \
294 ld_utrace_log(e, h, mb, ms, r, n); \
298 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
299 int refcnt, const char *name)
301 struct utrace_rtld ut;
309 ut.mapbase = mapbase;
310 ut.mapsize = mapsize;
312 bzero(ut.name, sizeof(ut.name));
314 strlcpy(ut.name, name, sizeof(ut.name));
315 utrace(&ut, sizeof(ut));
319 * Main entry point for dynamic linking. The first argument is the
320 * stack pointer. The stack is expected to be laid out as described
321 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
322 * Specifically, the stack pointer points to a word containing
323 * ARGC. Following that in the stack is a null-terminated sequence
324 * of pointers to argument strings. Then comes a null-terminated
325 * sequence of pointers to environment strings. Finally, there is a
326 * sequence of "auxiliary vector" entries.
328 * The second argument points to a place to store the dynamic linker's
329 * exit procedure pointer and the third to a place to store the main
332 * The return value is the main program's entry point.
335 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
337 Elf_Auxinfo *aux_info[AT_COUNT];
345 Objlist_Entry *entry;
347 Obj_Entry **preload_tail;
348 Obj_Entry *last_interposer;
350 RtldLockState lockstate;
351 char *library_path_rpath;
356 * On entry, the dynamic linker itself has not been relocated yet.
357 * Be very careful not to reference any global data until after
358 * init_rtld has returned. It is OK to reference file-scope statics
359 * and string constants, and to call static and global functions.
362 /* Find the auxiliary vector on the stack. */
365 sp += argc + 1; /* Skip over arguments and NULL terminator */
367 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
369 aux = (Elf_Auxinfo *) sp;
371 /* Digest the auxiliary vector. */
372 for (i = 0; i < AT_COUNT; i++)
374 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
375 if (auxp->a_type < AT_COUNT)
376 aux_info[auxp->a_type] = auxp;
379 /* Initialize and relocate ourselves. */
380 assert(aux_info[AT_BASE] != NULL);
381 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
383 __progname = obj_rtld.path;
384 argv0 = argv[0] != NULL ? argv[0] : "(null)";
389 if (aux_info[AT_CANARY] != NULL &&
390 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
391 i = aux_info[AT_CANARYLEN]->a_un.a_val;
392 if (i > sizeof(__stack_chk_guard))
393 i = sizeof(__stack_chk_guard);
394 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
399 len = sizeof(__stack_chk_guard);
400 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
401 len != sizeof(__stack_chk_guard)) {
402 /* If sysctl was unsuccessful, use the "terminator canary". */
403 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
404 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
405 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
406 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
410 trust = !issetugid();
412 ld_bind_now = getenv(LD_ "BIND_NOW");
414 * If the process is tainted, then we un-set the dangerous environment
415 * variables. The process will be marked as tainted until setuid(2)
416 * is called. If any child process calls setuid(2) we do not want any
417 * future processes to honor the potentially un-safe variables.
420 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
421 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") ||
422 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
423 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) {
424 _rtld_error("environment corrupt; aborting");
428 ld_debug = getenv(LD_ "DEBUG");
429 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
430 libmap_override = getenv(LD_ "LIBMAP");
431 ld_library_path = getenv(LD_ "LIBRARY_PATH");
432 ld_preload = getenv(LD_ "PRELOAD");
433 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
434 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
435 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH");
436 if (library_path_rpath != NULL) {
437 if (library_path_rpath[0] == 'y' ||
438 library_path_rpath[0] == 'Y' ||
439 library_path_rpath[0] == '1')
440 ld_library_path_rpath = true;
442 ld_library_path_rpath = false;
444 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
445 (ld_library_path != NULL) || (ld_preload != NULL) ||
446 (ld_elf_hints_path != NULL) || ld_loadfltr;
447 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
448 ld_utrace = getenv(LD_ "UTRACE");
450 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
451 ld_elf_hints_path = _PATH_ELF_HINTS;
453 if (ld_debug != NULL && *ld_debug != '\0')
455 dbg("%s is initialized, base address = %p", __progname,
456 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
457 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
458 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
460 dbg("initializing thread locks");
464 * Load the main program, or process its program header if it is
467 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
468 int fd = aux_info[AT_EXECFD]->a_un.a_val;
469 dbg("loading main program");
470 obj_main = map_object(fd, argv0, NULL);
472 if (obj_main == NULL)
474 max_stack_flags = obj->stack_flags;
475 } else { /* Main program already loaded. */
476 const Elf_Phdr *phdr;
480 dbg("processing main program's program header");
481 assert(aux_info[AT_PHDR] != NULL);
482 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
483 assert(aux_info[AT_PHNUM] != NULL);
484 phnum = aux_info[AT_PHNUM]->a_un.a_val;
485 assert(aux_info[AT_PHENT] != NULL);
486 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
487 assert(aux_info[AT_ENTRY] != NULL);
488 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
489 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
493 if (aux_info[AT_EXECPATH] != 0) {
495 char buf[MAXPATHLEN];
497 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
498 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
499 if (kexecpath[0] == '/')
500 obj_main->path = kexecpath;
501 else if (getcwd(buf, sizeof(buf)) == NULL ||
502 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
503 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
504 obj_main->path = xstrdup(argv0);
506 obj_main->path = xstrdup(buf);
508 dbg("No AT_EXECPATH");
509 obj_main->path = xstrdup(argv0);
511 dbg("obj_main path %s", obj_main->path);
512 obj_main->mainprog = true;
514 if (aux_info[AT_STACKPROT] != NULL &&
515 aux_info[AT_STACKPROT]->a_un.a_val != 0)
516 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
520 * Get the actual dynamic linker pathname from the executable if
521 * possible. (It should always be possible.) That ensures that
522 * gdb will find the right dynamic linker even if a non-standard
525 if (obj_main->interp != NULL &&
526 strcmp(obj_main->interp, obj_rtld.path) != 0) {
528 obj_rtld.path = xstrdup(obj_main->interp);
529 __progname = obj_rtld.path;
533 digest_dynamic(obj_main, 0);
534 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
535 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
536 obj_main->dynsymcount);
538 linkmap_add(obj_main);
539 linkmap_add(&obj_rtld);
541 /* Link the main program into the list of objects. */
542 *obj_tail = obj_main;
543 obj_tail = &obj_main->next;
547 /* Initialize a fake symbol for resolving undefined weak references. */
548 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
549 sym_zero.st_shndx = SHN_UNDEF;
550 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
553 libmap_disable = (bool)lm_init(libmap_override);
555 dbg("loading LD_PRELOAD libraries");
556 if (load_preload_objects() == -1)
558 preload_tail = obj_tail;
560 dbg("loading needed objects");
561 if (load_needed_objects(obj_main, 0) == -1)
564 /* Make a list of all objects loaded at startup. */
565 last_interposer = obj_main;
566 for (obj = obj_list; obj != NULL; obj = obj->next) {
567 if (obj->z_interpose && obj != obj_main) {
568 objlist_put_after(&list_main, last_interposer, obj);
569 last_interposer = obj;
571 objlist_push_tail(&list_main, obj);
576 dbg("checking for required versions");
577 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
580 if (ld_tracing) { /* We're done */
581 trace_loaded_objects(obj_main);
585 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
586 dump_relocations(obj_main);
591 * Processing tls relocations requires having the tls offsets
592 * initialized. Prepare offsets before starting initial
593 * relocation processing.
595 dbg("initializing initial thread local storage offsets");
596 STAILQ_FOREACH(entry, &list_main, link) {
598 * Allocate all the initial objects out of the static TLS
599 * block even if they didn't ask for it.
601 allocate_tls_offset(entry->obj);
604 if (relocate_objects(obj_main,
605 ld_bind_now != NULL && *ld_bind_now != '\0',
606 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
609 dbg("doing copy relocations");
610 if (do_copy_relocations(obj_main) == -1)
613 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
614 dump_relocations(obj_main);
619 * Setup TLS for main thread. This must be done after the
620 * relocations are processed, since tls initialization section
621 * might be the subject for relocations.
623 dbg("initializing initial thread local storage");
624 allocate_initial_tls(obj_list);
626 dbg("initializing key program variables");
627 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
628 set_program_var("environ", env);
629 set_program_var("__elf_aux_vector", aux);
631 /* Make a list of init functions to call. */
632 objlist_init(&initlist);
633 initlist_add_objects(obj_list, preload_tail, &initlist);
635 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
637 map_stacks_exec(NULL);
639 dbg("resolving ifuncs");
640 if (resolve_objects_ifunc(obj_main,
641 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
645 if (!obj_main->crt_no_init) {
647 * Make sure we don't call the main program's init and fini
648 * functions for binaries linked with old crt1 which calls
651 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
652 obj_main->preinit_array = obj_main->init_array =
653 obj_main->fini_array = (Elf_Addr)NULL;
656 wlock_acquire(rtld_bind_lock, &lockstate);
657 if (obj_main->crt_no_init)
659 objlist_call_init(&initlist, &lockstate);
660 _r_debug_postinit(&obj_main->linkmap);
661 objlist_clear(&initlist);
662 dbg("loading filtees");
663 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
664 if (ld_loadfltr || obj->z_loadfltr)
665 load_filtees(obj, 0, &lockstate);
667 lock_release(rtld_bind_lock, &lockstate);
669 dbg("transferring control to program entry point = %p", obj_main->entry);
671 /* Return the exit procedure and the program entry point. */
672 *exit_proc = rtld_exit;
674 return (func_ptr_type) obj_main->entry;
678 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
683 ptr = (void *)make_function_pointer(def, obj);
684 target = ((Elf_Addr (*)(void))ptr)();
685 return ((void *)target);
689 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
693 const Obj_Entry *defobj;
696 RtldLockState lockstate;
698 rlock_acquire(rtld_bind_lock, &lockstate);
699 if (sigsetjmp(lockstate.env, 0) != 0)
700 lock_upgrade(rtld_bind_lock, &lockstate);
702 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
704 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
706 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
707 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
711 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
712 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
714 target = (Elf_Addr)(defobj->relocbase + def->st_value);
716 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
717 defobj->strtab + def->st_name, basename(obj->path),
718 (void *)target, basename(defobj->path));
721 * Write the new contents for the jmpslot. Note that depending on
722 * architecture, the value which we need to return back to the
723 * lazy binding trampoline may or may not be the target
724 * address. The value returned from reloc_jmpslot() is the value
725 * that the trampoline needs.
727 target = reloc_jmpslot(where, target, defobj, obj, rel);
728 lock_release(rtld_bind_lock, &lockstate);
733 * Error reporting function. Use it like printf. If formats the message
734 * into a buffer, and sets things up so that the next call to dlerror()
735 * will return the message.
738 _rtld_error(const char *fmt, ...)
740 static char buf[512];
744 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
750 * Return a dynamically-allocated copy of the current error message, if any.
755 return error_message == NULL ? NULL : xstrdup(error_message);
759 * Restore the current error message from a copy which was previously saved
760 * by errmsg_save(). The copy is freed.
763 errmsg_restore(char *saved_msg)
765 if (saved_msg == NULL)
766 error_message = NULL;
768 _rtld_error("%s", saved_msg);
774 basename(const char *name)
776 const char *p = strrchr(name, '/');
777 return p != NULL ? p + 1 : name;
780 static struct utsname uts;
783 origin_subst_one(char *real, const char *kw, const char *subst,
786 char *p, *p1, *res, *resp;
787 int subst_len, kw_len, subst_count, old_len, new_len;
792 * First, count the number of the keyword occurences, to
793 * preallocate the final string.
795 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
802 * If the keyword is not found, just return.
804 if (subst_count == 0)
805 return (may_free ? real : xstrdup(real));
808 * There is indeed something to substitute. Calculate the
809 * length of the resulting string, and allocate it.
811 subst_len = strlen(subst);
812 old_len = strlen(real);
813 new_len = old_len + (subst_len - kw_len) * subst_count;
814 res = xmalloc(new_len + 1);
817 * Now, execute the substitution loop.
819 for (p = real, resp = res, *resp = '\0';;) {
822 /* Copy the prefix before keyword. */
823 memcpy(resp, p, p1 - p);
825 /* Keyword replacement. */
826 memcpy(resp, subst, subst_len);
834 /* Copy to the end of string and finish. */
842 origin_subst(char *real, const char *origin_path)
844 char *res1, *res2, *res3, *res4;
846 if (uts.sysname[0] == '\0') {
847 if (uname(&uts) != 0) {
848 _rtld_error("utsname failed: %d", errno);
852 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false);
853 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true);
854 res3 = origin_subst_one(res2, "$OSREL", uts.release, true);
855 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true);
862 const char *msg = dlerror();
866 rtld_fdputstr(STDERR_FILENO, msg);
867 rtld_fdputchar(STDERR_FILENO, '\n');
872 * Process a shared object's DYNAMIC section, and save the important
873 * information in its Obj_Entry structure.
876 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
877 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
880 Needed_Entry **needed_tail = &obj->needed;
881 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
882 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
883 const Elf_Hashelt *hashtab;
884 const Elf32_Word *hashval;
885 Elf32_Word bkt, nmaskwords;
887 int plttype = DT_REL;
893 obj->bind_now = false;
894 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
895 switch (dynp->d_tag) {
898 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
902 obj->relsize = dynp->d_un.d_val;
906 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
910 obj->pltrel = (const Elf_Rel *)
911 (obj->relocbase + dynp->d_un.d_ptr);
915 obj->pltrelsize = dynp->d_un.d_val;
919 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
923 obj->relasize = dynp->d_un.d_val;
927 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
931 plttype = dynp->d_un.d_val;
932 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
936 obj->symtab = (const Elf_Sym *)
937 (obj->relocbase + dynp->d_un.d_ptr);
941 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
945 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
949 obj->strsize = dynp->d_un.d_val;
953 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
958 obj->verneednum = dynp->d_un.d_val;
962 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
967 obj->verdefnum = dynp->d_un.d_val;
971 obj->versyms = (const Elf_Versym *)(obj->relocbase +
977 hashtab = (const Elf_Hashelt *)(obj->relocbase +
979 obj->nbuckets = hashtab[0];
980 obj->nchains = hashtab[1];
981 obj->buckets = hashtab + 2;
982 obj->chains = obj->buckets + obj->nbuckets;
983 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
984 obj->buckets != NULL;
990 hashtab = (const Elf_Hashelt *)(obj->relocbase +
992 obj->nbuckets_gnu = hashtab[0];
993 obj->symndx_gnu = hashtab[1];
994 nmaskwords = hashtab[2];
995 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
996 obj->maskwords_bm_gnu = nmaskwords - 1;
997 obj->shift2_gnu = hashtab[3];
998 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
999 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1000 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1002 /* Number of bitmask words is required to be power of 2 */
1003 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1004 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1010 Needed_Entry *nep = NEW(Needed_Entry);
1011 nep->name = dynp->d_un.d_val;
1016 needed_tail = &nep->next;
1022 Needed_Entry *nep = NEW(Needed_Entry);
1023 nep->name = dynp->d_un.d_val;
1027 *needed_filtees_tail = nep;
1028 needed_filtees_tail = &nep->next;
1034 Needed_Entry *nep = NEW(Needed_Entry);
1035 nep->name = dynp->d_un.d_val;
1039 *needed_aux_filtees_tail = nep;
1040 needed_aux_filtees_tail = &nep->next;
1045 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1049 obj->textrel = true;
1053 obj->symbolic = true;
1058 * We have to wait until later to process this, because we
1059 * might not have gotten the address of the string table yet.
1069 *dyn_runpath = dynp;
1073 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1076 case DT_PREINIT_ARRAY:
1077 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1080 case DT_PREINIT_ARRAYSZ:
1081 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1085 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1088 case DT_INIT_ARRAYSZ:
1089 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1093 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1097 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1100 case DT_FINI_ARRAYSZ:
1101 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1105 * Don't process DT_DEBUG on MIPS as the dynamic section
1106 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1111 /* XXX - not implemented yet */
1113 dbg("Filling in DT_DEBUG entry");
1114 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1119 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1120 obj->z_origin = true;
1121 if (dynp->d_un.d_val & DF_SYMBOLIC)
1122 obj->symbolic = true;
1123 if (dynp->d_un.d_val & DF_TEXTREL)
1124 obj->textrel = true;
1125 if (dynp->d_un.d_val & DF_BIND_NOW)
1126 obj->bind_now = true;
1127 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1131 case DT_MIPS_LOCAL_GOTNO:
1132 obj->local_gotno = dynp->d_un.d_val;
1135 case DT_MIPS_SYMTABNO:
1136 obj->symtabno = dynp->d_un.d_val;
1139 case DT_MIPS_GOTSYM:
1140 obj->gotsym = dynp->d_un.d_val;
1143 case DT_MIPS_RLD_MAP:
1144 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1149 if (dynp->d_un.d_val & DF_1_NOOPEN)
1150 obj->z_noopen = true;
1151 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1152 obj->z_origin = true;
1153 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1155 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1156 obj->bind_now = true;
1157 if (dynp->d_un.d_val & DF_1_NODELETE)
1158 obj->z_nodelete = true;
1159 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1160 obj->z_loadfltr = true;
1161 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1162 obj->z_interpose = true;
1163 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1164 obj->z_nodeflib = true;
1169 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1176 obj->traced = false;
1178 if (plttype == DT_RELA) {
1179 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1181 obj->pltrelasize = obj->pltrelsize;
1182 obj->pltrelsize = 0;
1185 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1186 if (obj->valid_hash_sysv)
1187 obj->dynsymcount = obj->nchains;
1188 else if (obj->valid_hash_gnu) {
1189 obj->dynsymcount = 0;
1190 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1191 if (obj->buckets_gnu[bkt] == 0)
1193 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1196 while ((*hashval++ & 1u) == 0);
1198 obj->dynsymcount += obj->symndx_gnu;
1203 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1204 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1207 if (obj->z_origin && obj->origin_path == NULL) {
1208 obj->origin_path = xmalloc(PATH_MAX);
1209 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1213 if (dyn_runpath != NULL) {
1214 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1216 obj->runpath = origin_subst(obj->runpath, obj->origin_path);
1218 else if (dyn_rpath != NULL) {
1219 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1221 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1224 if (dyn_soname != NULL)
1225 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1229 digest_dynamic(Obj_Entry *obj, int early)
1231 const Elf_Dyn *dyn_rpath;
1232 const Elf_Dyn *dyn_soname;
1233 const Elf_Dyn *dyn_runpath;
1235 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1236 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1240 * Process a shared object's program header. This is used only for the
1241 * main program, when the kernel has already loaded the main program
1242 * into memory before calling the dynamic linker. It creates and
1243 * returns an Obj_Entry structure.
1246 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1249 const Elf_Phdr *phlimit = phdr + phnum;
1251 Elf_Addr note_start, note_end;
1255 for (ph = phdr; ph < phlimit; ph++) {
1256 if (ph->p_type != PT_PHDR)
1260 obj->phsize = ph->p_memsz;
1261 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1265 obj->stack_flags = PF_X | PF_R | PF_W;
1267 for (ph = phdr; ph < phlimit; ph++) {
1268 switch (ph->p_type) {
1271 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1275 if (nsegs == 0) { /* First load segment */
1276 obj->vaddrbase = trunc_page(ph->p_vaddr);
1277 obj->mapbase = obj->vaddrbase + obj->relocbase;
1278 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1280 } else { /* Last load segment */
1281 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1288 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1293 obj->tlssize = ph->p_memsz;
1294 obj->tlsalign = ph->p_align;
1295 obj->tlsinitsize = ph->p_filesz;
1296 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1300 obj->stack_flags = ph->p_flags;
1304 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1305 obj->relro_size = round_page(ph->p_memsz);
1309 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1310 note_end = note_start + ph->p_filesz;
1311 digest_notes(obj, note_start, note_end);
1316 _rtld_error("%s: too few PT_LOAD segments", path);
1325 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1327 const Elf_Note *note;
1328 const char *note_name;
1331 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1332 note = (const Elf_Note *)((const char *)(note + 1) +
1333 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1334 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1335 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1336 note->n_descsz != sizeof(int32_t))
1338 if (note->n_type != ABI_NOTETYPE &&
1339 note->n_type != CRT_NOINIT_NOTETYPE)
1341 note_name = (const char *)(note + 1);
1342 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1343 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1345 switch (note->n_type) {
1347 /* FreeBSD osrel note */
1348 p = (uintptr_t)(note + 1);
1349 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1350 obj->osrel = *(const int32_t *)(p);
1351 dbg("note osrel %d", obj->osrel);
1353 case CRT_NOINIT_NOTETYPE:
1354 /* FreeBSD 'crt does not call init' note */
1355 obj->crt_no_init = true;
1356 dbg("note crt_no_init");
1363 dlcheck(void *handle)
1367 for (obj = obj_list; obj != NULL; obj = obj->next)
1368 if (obj == (Obj_Entry *) handle)
1371 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1372 _rtld_error("Invalid shared object handle %p", handle);
1379 * If the given object is already in the donelist, return true. Otherwise
1380 * add the object to the list and return false.
1383 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1387 for (i = 0; i < dlp->num_used; i++)
1388 if (dlp->objs[i] == obj)
1391 * Our donelist allocation should always be sufficient. But if
1392 * our threads locking isn't working properly, more shared objects
1393 * could have been loaded since we allocated the list. That should
1394 * never happen, but we'll handle it properly just in case it does.
1396 if (dlp->num_used < dlp->num_alloc)
1397 dlp->objs[dlp->num_used++] = obj;
1402 * Hash function for symbol table lookup. Don't even think about changing
1403 * this. It is specified by the System V ABI.
1406 elf_hash(const char *name)
1408 const unsigned char *p = (const unsigned char *) name;
1409 unsigned long h = 0;
1412 while (*p != '\0') {
1413 h = (h << 4) + *p++;
1414 if ((g = h & 0xf0000000) != 0)
1422 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1423 * unsigned in case it's implemented with a wider type.
1426 gnu_hash(const char *s)
1432 for (c = *s; c != '\0'; c = *++s)
1434 return (h & 0xffffffff);
1438 * Find the library with the given name, and return its full pathname.
1439 * The returned string is dynamically allocated. Generates an error
1440 * message and returns NULL if the library cannot be found.
1442 * If the second argument is non-NULL, then it refers to an already-
1443 * loaded shared object, whose library search path will be searched.
1445 * The search order is:
1446 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1447 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1449 * DT_RUNPATH in the referencing file
1450 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1452 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1454 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1457 find_library(const char *xname, const Obj_Entry *refobj)
1461 bool nodeflib, objgiven;
1463 objgiven = refobj != NULL;
1464 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1465 if (xname[0] != '/' && !trust) {
1466 _rtld_error("Absolute pathname required for shared object \"%s\"",
1470 if (objgiven && refobj->z_origin) {
1471 return (origin_subst(__DECONST(char *, xname),
1472 refobj->origin_path));
1474 return (xstrdup(xname));
1478 if (libmap_disable || !objgiven ||
1479 (name = lm_find(refobj->path, xname)) == NULL)
1480 name = (char *)xname;
1482 dbg(" Searching for \"%s\"", name);
1485 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1486 * back to pre-conforming behaviour if user requested so with
1487 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1490 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1491 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1493 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1494 (pathname = search_library_path(name, gethints(false))) != NULL ||
1495 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1498 nodeflib = objgiven ? refobj->z_nodeflib : false;
1500 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1501 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1502 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1503 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1505 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1506 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1507 (objgiven && !nodeflib &&
1508 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1512 if (objgiven && refobj->path != NULL) {
1513 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1514 name, basename(refobj->path));
1516 _rtld_error("Shared object \"%s\" not found", name);
1522 * Given a symbol number in a referencing object, find the corresponding
1523 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1524 * no definition was found. Returns a pointer to the Obj_Entry of the
1525 * defining object via the reference parameter DEFOBJ_OUT.
1528 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1529 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1530 RtldLockState *lockstate)
1534 const Obj_Entry *defobj;
1540 * If we have already found this symbol, get the information from
1543 if (symnum >= refobj->dynsymcount)
1544 return NULL; /* Bad object */
1545 if (cache != NULL && cache[symnum].sym != NULL) {
1546 *defobj_out = cache[symnum].obj;
1547 return cache[symnum].sym;
1550 ref = refobj->symtab + symnum;
1551 name = refobj->strtab + ref->st_name;
1556 * We don't have to do a full scale lookup if the symbol is local.
1557 * We know it will bind to the instance in this load module; to
1558 * which we already have a pointer (ie ref). By not doing a lookup,
1559 * we not only improve performance, but it also avoids unresolvable
1560 * symbols when local symbols are not in the hash table. This has
1561 * been seen with the ia64 toolchain.
1563 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1564 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1565 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1568 symlook_init(&req, name);
1570 req.ventry = fetch_ventry(refobj, symnum);
1571 req.lockstate = lockstate;
1572 res = symlook_default(&req, refobj);
1575 defobj = req.defobj_out;
1583 * If we found no definition and the reference is weak, treat the
1584 * symbol as having the value zero.
1586 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1592 *defobj_out = defobj;
1593 /* Record the information in the cache to avoid subsequent lookups. */
1594 if (cache != NULL) {
1595 cache[symnum].sym = def;
1596 cache[symnum].obj = defobj;
1599 if (refobj != &obj_rtld)
1600 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1606 * Return the search path from the ldconfig hints file, reading it if
1607 * necessary. If nostdlib is true, then the default search paths are
1608 * not added to result.
1610 * Returns NULL if there are problems with the hints file,
1611 * or if the search path there is empty.
1614 gethints(bool nostdlib)
1616 static char *hints, *filtered_path;
1617 struct elfhints_hdr hdr;
1618 struct fill_search_info_args sargs, hargs;
1619 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1620 struct dl_serpath *SLPpath, *hintpath;
1622 unsigned int SLPndx, hintndx, fndx, fcount;
1627 /* First call, read the hints file */
1628 if (hints == NULL) {
1629 /* Keep from trying again in case the hints file is bad. */
1632 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1634 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1635 hdr.magic != ELFHINTS_MAGIC ||
1640 p = xmalloc(hdr.dirlistlen + 1);
1641 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1642 read(fd, p, hdr.dirlistlen + 1) !=
1643 (ssize_t)hdr.dirlistlen + 1) {
1653 * If caller agreed to receive list which includes the default
1654 * paths, we are done. Otherwise, if we still did not
1655 * calculated filtered result, do it now.
1658 return (hints[0] != '\0' ? hints : NULL);
1659 if (filtered_path != NULL)
1663 * Obtain the list of all configured search paths, and the
1664 * list of the default paths.
1666 * First estimate the size of the results.
1668 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1670 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1673 sargs.request = RTLD_DI_SERINFOSIZE;
1674 sargs.serinfo = &smeta;
1675 hargs.request = RTLD_DI_SERINFOSIZE;
1676 hargs.serinfo = &hmeta;
1678 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1679 path_enumerate(p, fill_search_info, &hargs);
1681 SLPinfo = xmalloc(smeta.dls_size);
1682 hintinfo = xmalloc(hmeta.dls_size);
1685 * Next fetch both sets of paths.
1687 sargs.request = RTLD_DI_SERINFO;
1688 sargs.serinfo = SLPinfo;
1689 sargs.serpath = &SLPinfo->dls_serpath[0];
1690 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1692 hargs.request = RTLD_DI_SERINFO;
1693 hargs.serinfo = hintinfo;
1694 hargs.serpath = &hintinfo->dls_serpath[0];
1695 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1697 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1698 path_enumerate(p, fill_search_info, &hargs);
1701 * Now calculate the difference between two sets, by excluding
1702 * standard paths from the full set.
1706 filtered_path = xmalloc(hdr.dirlistlen + 1);
1707 hintpath = &hintinfo->dls_serpath[0];
1708 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1710 SLPpath = &SLPinfo->dls_serpath[0];
1712 * Check each standard path against current.
1714 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1715 /* matched, skip the path */
1716 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1724 * Not matched against any standard path, add the path
1725 * to result. Separate consequtive paths with ':'.
1728 filtered_path[fndx] = ':';
1732 flen = strlen(hintpath->dls_name);
1733 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1736 filtered_path[fndx] = '\0';
1742 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1746 init_dag(Obj_Entry *root)
1748 const Needed_Entry *needed;
1749 const Objlist_Entry *elm;
1752 if (root->dag_inited)
1754 donelist_init(&donelist);
1756 /* Root object belongs to own DAG. */
1757 objlist_push_tail(&root->dldags, root);
1758 objlist_push_tail(&root->dagmembers, root);
1759 donelist_check(&donelist, root);
1762 * Add dependencies of root object to DAG in breadth order
1763 * by exploiting the fact that each new object get added
1764 * to the tail of the dagmembers list.
1766 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1767 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1768 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1770 objlist_push_tail(&needed->obj->dldags, root);
1771 objlist_push_tail(&root->dagmembers, needed->obj);
1774 root->dag_inited = true;
1778 process_nodelete(Obj_Entry *root)
1780 const Objlist_Entry *elm;
1783 * Walk over object DAG and process every dependent object that
1784 * is marked as DF_1_NODELETE. They need to grow their own DAG,
1785 * which then should have its reference upped separately.
1787 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1788 if (elm->obj != NULL && elm->obj->z_nodelete &&
1789 !elm->obj->ref_nodel) {
1790 dbg("obj %s nodelete", elm->obj->path);
1793 elm->obj->ref_nodel = true;
1798 * Initialize the dynamic linker. The argument is the address at which
1799 * the dynamic linker has been mapped into memory. The primary task of
1800 * this function is to relocate the dynamic linker.
1803 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1805 Obj_Entry objtmp; /* Temporary rtld object */
1806 const Elf_Dyn *dyn_rpath;
1807 const Elf_Dyn *dyn_soname;
1808 const Elf_Dyn *dyn_runpath;
1810 #ifdef RTLD_INIT_PAGESIZES_EARLY
1811 /* The page size is required by the dynamic memory allocator. */
1812 init_pagesizes(aux_info);
1816 * Conjure up an Obj_Entry structure for the dynamic linker.
1818 * The "path" member can't be initialized yet because string constants
1819 * cannot yet be accessed. Below we will set it correctly.
1821 memset(&objtmp, 0, sizeof(objtmp));
1824 objtmp.mapbase = mapbase;
1826 objtmp.relocbase = mapbase;
1828 if (RTLD_IS_DYNAMIC()) {
1829 objtmp.dynamic = rtld_dynamic(&objtmp);
1830 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1831 assert(objtmp.needed == NULL);
1832 #if !defined(__mips__)
1833 /* MIPS has a bogus DT_TEXTREL. */
1834 assert(!objtmp.textrel);
1838 * Temporarily put the dynamic linker entry into the object list, so
1839 * that symbols can be found.
1842 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1845 /* Initialize the object list. */
1846 obj_tail = &obj_list;
1848 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1849 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1851 #ifndef RTLD_INIT_PAGESIZES_EARLY
1852 /* The page size is required by the dynamic memory allocator. */
1853 init_pagesizes(aux_info);
1856 if (aux_info[AT_OSRELDATE] != NULL)
1857 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1859 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1861 /* Replace the path with a dynamically allocated copy. */
1862 obj_rtld.path = xstrdup(PATH_RTLD);
1864 r_debug.r_brk = r_debug_state;
1865 r_debug.r_state = RT_CONSISTENT;
1869 * Retrieve the array of supported page sizes. The kernel provides the page
1870 * sizes in increasing order.
1873 init_pagesizes(Elf_Auxinfo **aux_info)
1875 static size_t psa[MAXPAGESIZES];
1879 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
1881 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
1882 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
1885 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
1888 /* As a fallback, retrieve the base page size. */
1889 size = sizeof(psa[0]);
1890 if (aux_info[AT_PAGESZ] != NULL) {
1891 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
1895 mib[1] = HW_PAGESIZE;
1899 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
1900 _rtld_error("sysctl for hw.pagesize(s) failed");
1906 npagesizes = size / sizeof(pagesizes[0]);
1907 /* Discard any invalid entries at the end of the array. */
1908 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
1913 * Add the init functions from a needed object list (and its recursive
1914 * needed objects) to "list". This is not used directly; it is a helper
1915 * function for initlist_add_objects(). The write lock must be held
1916 * when this function is called.
1919 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1921 /* Recursively process the successor needed objects. */
1922 if (needed->next != NULL)
1923 initlist_add_neededs(needed->next, list);
1925 /* Process the current needed object. */
1926 if (needed->obj != NULL)
1927 initlist_add_objects(needed->obj, &needed->obj->next, list);
1931 * Scan all of the DAGs rooted in the range of objects from "obj" to
1932 * "tail" and add their init functions to "list". This recurses over
1933 * the DAGs and ensure the proper init ordering such that each object's
1934 * needed libraries are initialized before the object itself. At the
1935 * same time, this function adds the objects to the global finalization
1936 * list "list_fini" in the opposite order. The write lock must be
1937 * held when this function is called.
1940 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1943 if (obj->init_scanned || obj->init_done)
1945 obj->init_scanned = true;
1947 /* Recursively process the successor objects. */
1948 if (&obj->next != tail)
1949 initlist_add_objects(obj->next, tail, list);
1951 /* Recursively process the needed objects. */
1952 if (obj->needed != NULL)
1953 initlist_add_neededs(obj->needed, list);
1954 if (obj->needed_filtees != NULL)
1955 initlist_add_neededs(obj->needed_filtees, list);
1956 if (obj->needed_aux_filtees != NULL)
1957 initlist_add_neededs(obj->needed_aux_filtees, list);
1959 /* Add the object to the init list. */
1960 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1961 obj->init_array != (Elf_Addr)NULL)
1962 objlist_push_tail(list, obj);
1964 /* Add the object to the global fini list in the reverse order. */
1965 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1966 && !obj->on_fini_list) {
1967 objlist_push_head(&list_fini, obj);
1968 obj->on_fini_list = true;
1973 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1977 free_needed_filtees(Needed_Entry *n)
1979 Needed_Entry *needed, *needed1;
1981 for (needed = n; needed != NULL; needed = needed->next) {
1982 if (needed->obj != NULL) {
1983 dlclose(needed->obj);
1987 for (needed = n; needed != NULL; needed = needed1) {
1988 needed1 = needed->next;
1994 unload_filtees(Obj_Entry *obj)
1997 free_needed_filtees(obj->needed_filtees);
1998 obj->needed_filtees = NULL;
1999 free_needed_filtees(obj->needed_aux_filtees);
2000 obj->needed_aux_filtees = NULL;
2001 obj->filtees_loaded = false;
2005 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2006 RtldLockState *lockstate)
2009 for (; needed != NULL; needed = needed->next) {
2010 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2011 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2012 RTLD_LOCAL, lockstate);
2017 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2020 lock_restart_for_upgrade(lockstate);
2021 if (!obj->filtees_loaded) {
2022 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2023 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2024 obj->filtees_loaded = true;
2029 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2033 for (; needed != NULL; needed = needed->next) {
2034 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2035 flags & ~RTLD_LO_NOLOAD);
2036 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2043 * Given a shared object, traverse its list of needed objects, and load
2044 * each of them. Returns 0 on success. Generates an error message and
2045 * returns -1 on failure.
2048 load_needed_objects(Obj_Entry *first, int flags)
2052 for (obj = first; obj != NULL; obj = obj->next) {
2053 if (process_needed(obj, obj->needed, flags) == -1)
2060 load_preload_objects(void)
2062 char *p = ld_preload;
2064 static const char delim[] = " \t:;";
2069 p += strspn(p, delim);
2070 while (*p != '\0') {
2071 size_t len = strcspn(p, delim);
2076 obj = load_object(p, -1, NULL, 0);
2078 return -1; /* XXX - cleanup */
2079 obj->z_interpose = true;
2082 p += strspn(p, delim);
2084 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2089 printable_path(const char *path)
2092 return (path == NULL ? "<unknown>" : path);
2096 * Load a shared object into memory, if it is not already loaded. The
2097 * object may be specified by name or by user-supplied file descriptor
2098 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2101 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2105 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2113 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2114 if (object_match_name(obj, name))
2118 path = find_library(name, refobj);
2125 * If we didn't find a match by pathname, or the name is not
2126 * supplied, open the file and check again by device and inode.
2127 * This avoids false mismatches caused by multiple links or ".."
2130 * To avoid a race, we open the file and use fstat() rather than
2135 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) {
2136 _rtld_error("Cannot open \"%s\"", path);
2141 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2143 _rtld_error("Cannot dup fd");
2148 if (fstat(fd, &sb) == -1) {
2149 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2154 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2155 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2157 if (obj != NULL && name != NULL) {
2158 object_add_name(obj, name);
2163 if (flags & RTLD_LO_NOLOAD) {
2169 /* First use of this object, so we must map it in */
2170 obj = do_load_object(fd, name, path, &sb, flags);
2179 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2186 * but first, make sure that environment variables haven't been
2187 * used to circumvent the noexec flag on a filesystem.
2189 if (dangerous_ld_env) {
2190 if (fstatfs(fd, &fs) != 0) {
2191 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2194 if (fs.f_flags & MNT_NOEXEC) {
2195 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2199 dbg("loading \"%s\"", printable_path(path));
2200 obj = map_object(fd, printable_path(path), sbp);
2205 * If DT_SONAME is present in the object, digest_dynamic2 already
2206 * added it to the object names.
2209 object_add_name(obj, name);
2211 digest_dynamic(obj, 0);
2212 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2213 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2214 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2216 dbg("refusing to load non-loadable \"%s\"", obj->path);
2217 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2218 munmap(obj->mapbase, obj->mapsize);
2223 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2225 obj_tail = &obj->next;
2228 linkmap_add(obj); /* for GDB & dlinfo() */
2229 max_stack_flags |= obj->stack_flags;
2231 dbg(" %p .. %p: %s", obj->mapbase,
2232 obj->mapbase + obj->mapsize - 1, obj->path);
2234 dbg(" WARNING: %s has impure text", obj->path);
2235 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2242 obj_from_addr(const void *addr)
2246 for (obj = obj_list; obj != NULL; obj = obj->next) {
2247 if (addr < (void *) obj->mapbase)
2249 if (addr < (void *) (obj->mapbase + obj->mapsize))
2258 Elf_Addr *preinit_addr;
2261 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2262 if (preinit_addr == NULL)
2265 for (index = 0; index < obj_main->preinit_array_num; index++) {
2266 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2267 dbg("calling preinit function for %s at %p", obj_main->path,
2268 (void *)preinit_addr[index]);
2269 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2270 0, 0, obj_main->path);
2271 call_init_pointer(obj_main, preinit_addr[index]);
2277 * Call the finalization functions for each of the objects in "list"
2278 * belonging to the DAG of "root" and referenced once. If NULL "root"
2279 * is specified, every finalization function will be called regardless
2280 * of the reference count and the list elements won't be freed. All of
2281 * the objects are expected to have non-NULL fini functions.
2284 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2288 Elf_Addr *fini_addr;
2291 assert(root == NULL || root->refcount == 1);
2294 * Preserve the current error message since a fini function might
2295 * call into the dynamic linker and overwrite it.
2297 saved_msg = errmsg_save();
2299 STAILQ_FOREACH(elm, list, link) {
2300 if (root != NULL && (elm->obj->refcount != 1 ||
2301 objlist_find(&root->dagmembers, elm->obj) == NULL))
2303 /* Remove object from fini list to prevent recursive invocation. */
2304 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2306 * XXX: If a dlopen() call references an object while the
2307 * fini function is in progress, we might end up trying to
2308 * unload the referenced object in dlclose() or the object
2309 * won't be unloaded although its fini function has been
2312 lock_release(rtld_bind_lock, lockstate);
2315 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2316 * When this happens, DT_FINI_ARRAY is processed first.
2318 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2319 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2320 for (index = elm->obj->fini_array_num - 1; index >= 0;
2322 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2323 dbg("calling fini function for %s at %p",
2324 elm->obj->path, (void *)fini_addr[index]);
2325 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2326 (void *)fini_addr[index], 0, 0, elm->obj->path);
2327 call_initfini_pointer(elm->obj, fini_addr[index]);
2331 if (elm->obj->fini != (Elf_Addr)NULL) {
2332 dbg("calling fini function for %s at %p", elm->obj->path,
2333 (void *)elm->obj->fini);
2334 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2335 0, 0, elm->obj->path);
2336 call_initfini_pointer(elm->obj, elm->obj->fini);
2338 wlock_acquire(rtld_bind_lock, lockstate);
2339 /* No need to free anything if process is going down. */
2343 * We must restart the list traversal after every fini call
2344 * because a dlclose() call from the fini function or from
2345 * another thread might have modified the reference counts.
2349 } while (elm != NULL);
2350 errmsg_restore(saved_msg);
2354 * Call the initialization functions for each of the objects in
2355 * "list". All of the objects are expected to have non-NULL init
2359 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2364 Elf_Addr *init_addr;
2368 * Clean init_scanned flag so that objects can be rechecked and
2369 * possibly initialized earlier if any of vectors called below
2370 * cause the change by using dlopen.
2372 for (obj = obj_list; obj != NULL; obj = obj->next)
2373 obj->init_scanned = false;
2376 * Preserve the current error message since an init function might
2377 * call into the dynamic linker and overwrite it.
2379 saved_msg = errmsg_save();
2380 STAILQ_FOREACH(elm, list, link) {
2381 if (elm->obj->init_done) /* Initialized early. */
2384 * Race: other thread might try to use this object before current
2385 * one completes the initilization. Not much can be done here
2386 * without better locking.
2388 elm->obj->init_done = true;
2389 lock_release(rtld_bind_lock, lockstate);
2392 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2393 * When this happens, DT_INIT is processed first.
2395 if (elm->obj->init != (Elf_Addr)NULL) {
2396 dbg("calling init function for %s at %p", elm->obj->path,
2397 (void *)elm->obj->init);
2398 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2399 0, 0, elm->obj->path);
2400 call_initfini_pointer(elm->obj, elm->obj->init);
2402 init_addr = (Elf_Addr *)elm->obj->init_array;
2403 if (init_addr != NULL) {
2404 for (index = 0; index < elm->obj->init_array_num; index++) {
2405 if (init_addr[index] != 0 && init_addr[index] != 1) {
2406 dbg("calling init function for %s at %p", elm->obj->path,
2407 (void *)init_addr[index]);
2408 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2409 (void *)init_addr[index], 0, 0, elm->obj->path);
2410 call_init_pointer(elm->obj, init_addr[index]);
2414 wlock_acquire(rtld_bind_lock, lockstate);
2416 errmsg_restore(saved_msg);
2420 objlist_clear(Objlist *list)
2424 while (!STAILQ_EMPTY(list)) {
2425 elm = STAILQ_FIRST(list);
2426 STAILQ_REMOVE_HEAD(list, link);
2431 static Objlist_Entry *
2432 objlist_find(Objlist *list, const Obj_Entry *obj)
2436 STAILQ_FOREACH(elm, list, link)
2437 if (elm->obj == obj)
2443 objlist_init(Objlist *list)
2449 objlist_push_head(Objlist *list, Obj_Entry *obj)
2453 elm = NEW(Objlist_Entry);
2455 STAILQ_INSERT_HEAD(list, elm, link);
2459 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2463 elm = NEW(Objlist_Entry);
2465 STAILQ_INSERT_TAIL(list, elm, link);
2469 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2471 Objlist_Entry *elm, *listelm;
2473 STAILQ_FOREACH(listelm, list, link) {
2474 if (listelm->obj == listobj)
2477 elm = NEW(Objlist_Entry);
2479 if (listelm != NULL)
2480 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2482 STAILQ_INSERT_TAIL(list, elm, link);
2486 objlist_remove(Objlist *list, Obj_Entry *obj)
2490 if ((elm = objlist_find(list, obj)) != NULL) {
2491 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2497 * Relocate dag rooted in the specified object.
2498 * Returns 0 on success, or -1 on failure.
2502 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2503 int flags, RtldLockState *lockstate)
2509 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2510 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2519 * Relocate single object.
2520 * Returns 0 on success, or -1 on failure.
2523 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2524 int flags, RtldLockState *lockstate)
2529 obj->relocated = true;
2531 dbg("relocating \"%s\"", obj->path);
2533 if (obj->symtab == NULL || obj->strtab == NULL ||
2534 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2535 _rtld_error("%s: Shared object has no run-time symbol table",
2541 /* There are relocations to the write-protected text segment. */
2542 if (mprotect(obj->mapbase, obj->textsize,
2543 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2544 _rtld_error("%s: Cannot write-enable text segment: %s",
2545 obj->path, rtld_strerror(errno));
2550 /* Process the non-PLT non-IFUNC relocations. */
2551 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2554 if (obj->textrel) { /* Re-protected the text segment. */
2555 if (mprotect(obj->mapbase, obj->textsize,
2556 PROT_READ|PROT_EXEC) == -1) {
2557 _rtld_error("%s: Cannot write-protect text segment: %s",
2558 obj->path, rtld_strerror(errno));
2563 /* Set the special PLT or GOT entries. */
2566 /* Process the PLT relocations. */
2567 if (reloc_plt(obj) == -1)
2569 /* Relocate the jump slots if we are doing immediate binding. */
2570 if (obj->bind_now || bind_now)
2571 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2575 * Process the non-PLT IFUNC relocations. The relocations are
2576 * processed in two phases, because IFUNC resolvers may
2577 * reference other symbols, which must be readily processed
2578 * before resolvers are called.
2580 if (obj->non_plt_gnu_ifunc &&
2581 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
2584 if (obj->relro_size > 0) {
2585 if (mprotect(obj->relro_page, obj->relro_size,
2587 _rtld_error("%s: Cannot enforce relro protection: %s",
2588 obj->path, rtld_strerror(errno));
2594 * Set up the magic number and version in the Obj_Entry. These
2595 * were checked in the crt1.o from the original ElfKit, so we
2596 * set them for backward compatibility.
2598 obj->magic = RTLD_MAGIC;
2599 obj->version = RTLD_VERSION;
2605 * Relocate newly-loaded shared objects. The argument is a pointer to
2606 * the Obj_Entry for the first such object. All objects from the first
2607 * to the end of the list of objects are relocated. Returns 0 on success,
2611 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2612 int flags, RtldLockState *lockstate)
2617 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2618 error = relocate_object(obj, bind_now, rtldobj, flags,
2627 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2628 * referencing STT_GNU_IFUNC symbols is postponed till the other
2629 * relocations are done. The indirect functions specified as
2630 * ifunc are allowed to call other symbols, so we need to have
2631 * objects relocated before asking for resolution from indirects.
2633 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2634 * instead of the usual lazy handling of PLT slots. It is
2635 * consistent with how GNU does it.
2638 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2639 RtldLockState *lockstate)
2641 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2643 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2644 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2650 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2651 RtldLockState *lockstate)
2655 for (obj = first; obj != NULL; obj = obj->next) {
2656 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2663 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2664 RtldLockState *lockstate)
2668 STAILQ_FOREACH(elm, list, link) {
2669 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2677 * Cleanup procedure. It will be called (by the atexit mechanism) just
2678 * before the process exits.
2683 RtldLockState lockstate;
2685 wlock_acquire(rtld_bind_lock, &lockstate);
2687 objlist_call_fini(&list_fini, NULL, &lockstate);
2688 /* No need to remove the items from the list, since we are exiting. */
2689 if (!libmap_disable)
2691 lock_release(rtld_bind_lock, &lockstate);
2695 * Iterate over a search path, translate each element, and invoke the
2696 * callback on the result.
2699 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2705 path += strspn(path, ":;");
2706 while (*path != '\0') {
2710 len = strcspn(path, ":;");
2711 trans = lm_findn(NULL, path, len);
2713 res = callback(trans, strlen(trans), arg);
2715 res = callback(path, len, arg);
2721 path += strspn(path, ":;");
2727 struct try_library_args {
2735 try_library_path(const char *dir, size_t dirlen, void *param)
2737 struct try_library_args *arg;
2740 if (*dir == '/' || trust) {
2743 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2746 pathname = arg->buffer;
2747 strncpy(pathname, dir, dirlen);
2748 pathname[dirlen] = '/';
2749 strcpy(pathname + dirlen + 1, arg->name);
2751 dbg(" Trying \"%s\"", pathname);
2752 if (access(pathname, F_OK) == 0) { /* We found it */
2753 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2754 strcpy(pathname, arg->buffer);
2762 search_library_path(const char *name, const char *path)
2765 struct try_library_args arg;
2771 arg.namelen = strlen(name);
2772 arg.buffer = xmalloc(PATH_MAX);
2773 arg.buflen = PATH_MAX;
2775 p = path_enumerate(path, try_library_path, &arg);
2783 dlclose(void *handle)
2786 RtldLockState lockstate;
2788 wlock_acquire(rtld_bind_lock, &lockstate);
2789 root = dlcheck(handle);
2791 lock_release(rtld_bind_lock, &lockstate);
2794 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2797 /* Unreference the object and its dependencies. */
2798 root->dl_refcount--;
2800 if (root->refcount == 1) {
2802 * The object will be no longer referenced, so we must unload it.
2803 * First, call the fini functions.
2805 objlist_call_fini(&list_fini, root, &lockstate);
2809 /* Finish cleaning up the newly-unreferenced objects. */
2810 GDB_STATE(RT_DELETE,&root->linkmap);
2811 unload_object(root);
2812 GDB_STATE(RT_CONSISTENT,NULL);
2816 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2817 lock_release(rtld_bind_lock, &lockstate);
2824 char *msg = error_message;
2825 error_message = NULL;
2830 * This function is deprecated and has no effect.
2833 dllockinit(void *context,
2834 void *(*lock_create)(void *context),
2835 void (*rlock_acquire)(void *lock),
2836 void (*wlock_acquire)(void *lock),
2837 void (*lock_release)(void *lock),
2838 void (*lock_destroy)(void *lock),
2839 void (*context_destroy)(void *context))
2841 static void *cur_context;
2842 static void (*cur_context_destroy)(void *);
2844 /* Just destroy the context from the previous call, if necessary. */
2845 if (cur_context_destroy != NULL)
2846 cur_context_destroy(cur_context);
2847 cur_context = context;
2848 cur_context_destroy = context_destroy;
2852 dlopen(const char *name, int mode)
2855 return (rtld_dlopen(name, -1, mode));
2859 fdlopen(int fd, int mode)
2862 return (rtld_dlopen(NULL, fd, mode));
2866 rtld_dlopen(const char *name, int fd, int mode)
2868 RtldLockState lockstate;
2871 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2872 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2873 if (ld_tracing != NULL) {
2874 rlock_acquire(rtld_bind_lock, &lockstate);
2875 if (sigsetjmp(lockstate.env, 0) != 0)
2876 lock_upgrade(rtld_bind_lock, &lockstate);
2877 environ = (char **)*get_program_var_addr("environ", &lockstate);
2878 lock_release(rtld_bind_lock, &lockstate);
2880 lo_flags = RTLD_LO_DLOPEN;
2881 if (mode & RTLD_NODELETE)
2882 lo_flags |= RTLD_LO_NODELETE;
2883 if (mode & RTLD_NOLOAD)
2884 lo_flags |= RTLD_LO_NOLOAD;
2885 if (ld_tracing != NULL)
2886 lo_flags |= RTLD_LO_TRACE;
2888 return (dlopen_object(name, fd, obj_main, lo_flags,
2889 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
2893 dlopen_cleanup(Obj_Entry *obj)
2898 if (obj->refcount == 0)
2903 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2904 int mode, RtldLockState *lockstate)
2906 Obj_Entry **old_obj_tail;
2909 RtldLockState mlockstate;
2912 objlist_init(&initlist);
2914 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
2915 wlock_acquire(rtld_bind_lock, &mlockstate);
2916 lockstate = &mlockstate;
2918 GDB_STATE(RT_ADD,NULL);
2920 old_obj_tail = obj_tail;
2922 if (name == NULL && fd == -1) {
2926 obj = load_object(name, fd, refobj, lo_flags);
2931 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2932 objlist_push_tail(&list_global, obj);
2933 if (*old_obj_tail != NULL) { /* We loaded something new. */
2934 assert(*old_obj_tail == obj);
2935 result = load_needed_objects(obj,
2936 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
2940 result = rtld_verify_versions(&obj->dagmembers);
2941 if (result != -1 && ld_tracing)
2943 if (result == -1 || relocate_object_dag(obj,
2944 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
2945 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2947 dlopen_cleanup(obj);
2949 } else if (lo_flags & RTLD_LO_EARLY) {
2951 * Do not call the init functions for early loaded
2952 * filtees. The image is still not initialized enough
2955 * Our object is found by the global object list and
2956 * will be ordered among all init calls done right
2957 * before transferring control to main.
2960 /* Make list of init functions to call. */
2961 initlist_add_objects(obj, &obj->next, &initlist);
2964 * Process all no_delete objects here, given them own
2965 * DAGs to prevent their dependencies from being unloaded.
2966 * This has to be done after we have loaded all of the
2967 * dependencies, so that we do not miss any.
2970 process_nodelete(obj);
2973 * Bump the reference counts for objects on this DAG. If
2974 * this is the first dlopen() call for the object that was
2975 * already loaded as a dependency, initialize the dag
2981 if ((lo_flags & RTLD_LO_TRACE) != 0)
2984 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2985 obj->z_nodelete) && !obj->ref_nodel) {
2986 dbg("obj %s nodelete", obj->path);
2988 obj->z_nodelete = obj->ref_nodel = true;
2992 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2994 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2996 if (!(lo_flags & RTLD_LO_EARLY)) {
2997 map_stacks_exec(lockstate);
3000 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3001 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3003 objlist_clear(&initlist);
3004 dlopen_cleanup(obj);
3005 if (lockstate == &mlockstate)
3006 lock_release(rtld_bind_lock, lockstate);
3010 if (!(lo_flags & RTLD_LO_EARLY)) {
3011 /* Call the init functions. */
3012 objlist_call_init(&initlist, lockstate);
3014 objlist_clear(&initlist);
3015 if (lockstate == &mlockstate)
3016 lock_release(rtld_bind_lock, lockstate);
3019 trace_loaded_objects(obj);
3020 if (lockstate == &mlockstate)
3021 lock_release(rtld_bind_lock, lockstate);
3026 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3030 const Obj_Entry *obj, *defobj;
3033 RtldLockState lockstate;
3041 symlook_init(&req, name);
3043 req.flags = flags | SYMLOOK_IN_PLT;
3044 req.lockstate = &lockstate;
3046 rlock_acquire(rtld_bind_lock, &lockstate);
3047 if (sigsetjmp(lockstate.env, 0) != 0)
3048 lock_upgrade(rtld_bind_lock, &lockstate);
3049 if (handle == NULL || handle == RTLD_NEXT ||
3050 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3052 if ((obj = obj_from_addr(retaddr)) == NULL) {
3053 _rtld_error("Cannot determine caller's shared object");
3054 lock_release(rtld_bind_lock, &lockstate);
3057 if (handle == NULL) { /* Just the caller's shared object. */
3058 res = symlook_obj(&req, obj);
3061 defobj = req.defobj_out;
3063 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3064 handle == RTLD_SELF) { /* ... caller included */
3065 if (handle == RTLD_NEXT)
3067 for (; obj != NULL; obj = obj->next) {
3068 res = symlook_obj(&req, obj);
3071 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3073 defobj = req.defobj_out;
3074 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3080 * Search the dynamic linker itself, and possibly resolve the
3081 * symbol from there. This is how the application links to
3082 * dynamic linker services such as dlopen.
3084 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3085 res = symlook_obj(&req, &obj_rtld);
3088 defobj = req.defobj_out;
3092 assert(handle == RTLD_DEFAULT);
3093 res = symlook_default(&req, obj);
3095 defobj = req.defobj_out;
3100 if ((obj = dlcheck(handle)) == NULL) {
3101 lock_release(rtld_bind_lock, &lockstate);
3105 donelist_init(&donelist);
3106 if (obj->mainprog) {
3107 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3108 res = symlook_global(&req, &donelist);
3111 defobj = req.defobj_out;
3114 * Search the dynamic linker itself, and possibly resolve the
3115 * symbol from there. This is how the application links to
3116 * dynamic linker services such as dlopen.
3118 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3119 res = symlook_obj(&req, &obj_rtld);
3122 defobj = req.defobj_out;
3127 /* Search the whole DAG rooted at the given object. */
3128 res = symlook_list(&req, &obj->dagmembers, &donelist);
3131 defobj = req.defobj_out;
3137 lock_release(rtld_bind_lock, &lockstate);
3140 * The value required by the caller is derived from the value
3141 * of the symbol. For the ia64 architecture, we need to
3142 * construct a function descriptor which the caller can use to
3143 * call the function with the right 'gp' value. For other
3144 * architectures and for non-functions, the value is simply
3145 * the relocated value of the symbol.
3147 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3148 return (make_function_pointer(def, defobj));
3149 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3150 return (rtld_resolve_ifunc(defobj, def));
3151 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3153 return (__tls_get_addr(defobj->tlsindex, def->st_value));
3155 ti.ti_module = defobj->tlsindex;
3156 ti.ti_offset = def->st_value;
3157 return (__tls_get_addr(&ti));
3160 return (defobj->relocbase + def->st_value);
3163 _rtld_error("Undefined symbol \"%s\"", name);
3164 lock_release(rtld_bind_lock, &lockstate);
3169 dlsym(void *handle, const char *name)
3171 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3176 dlfunc(void *handle, const char *name)
3183 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3189 dlvsym(void *handle, const char *name, const char *version)
3193 ventry.name = version;
3195 ventry.hash = elf_hash(version);
3197 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3202 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3204 const Obj_Entry *obj;
3205 RtldLockState lockstate;
3207 rlock_acquire(rtld_bind_lock, &lockstate);
3208 obj = obj_from_addr(addr);
3210 _rtld_error("No shared object contains address");
3211 lock_release(rtld_bind_lock, &lockstate);
3214 rtld_fill_dl_phdr_info(obj, phdr_info);
3215 lock_release(rtld_bind_lock, &lockstate);
3220 dladdr(const void *addr, Dl_info *info)
3222 const Obj_Entry *obj;
3225 unsigned long symoffset;
3226 RtldLockState lockstate;
3228 rlock_acquire(rtld_bind_lock, &lockstate);
3229 obj = obj_from_addr(addr);
3231 _rtld_error("No shared object contains address");
3232 lock_release(rtld_bind_lock, &lockstate);
3235 info->dli_fname = obj->path;
3236 info->dli_fbase = obj->mapbase;
3237 info->dli_saddr = (void *)0;
3238 info->dli_sname = NULL;
3241 * Walk the symbol list looking for the symbol whose address is
3242 * closest to the address sent in.
3244 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3245 def = obj->symtab + symoffset;
3248 * For skip the symbol if st_shndx is either SHN_UNDEF or
3251 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3255 * If the symbol is greater than the specified address, or if it
3256 * is further away from addr than the current nearest symbol,
3259 symbol_addr = obj->relocbase + def->st_value;
3260 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3263 /* Update our idea of the nearest symbol. */
3264 info->dli_sname = obj->strtab + def->st_name;
3265 info->dli_saddr = symbol_addr;
3268 if (info->dli_saddr == addr)
3271 lock_release(rtld_bind_lock, &lockstate);
3276 dlinfo(void *handle, int request, void *p)
3278 const Obj_Entry *obj;
3279 RtldLockState lockstate;
3282 rlock_acquire(rtld_bind_lock, &lockstate);
3284 if (handle == NULL || handle == RTLD_SELF) {
3287 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3288 if ((obj = obj_from_addr(retaddr)) == NULL)
3289 _rtld_error("Cannot determine caller's shared object");
3291 obj = dlcheck(handle);
3294 lock_release(rtld_bind_lock, &lockstate);
3300 case RTLD_DI_LINKMAP:
3301 *((struct link_map const **)p) = &obj->linkmap;
3303 case RTLD_DI_ORIGIN:
3304 error = rtld_dirname(obj->path, p);
3307 case RTLD_DI_SERINFOSIZE:
3308 case RTLD_DI_SERINFO:
3309 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3313 _rtld_error("Invalid request %d passed to dlinfo()", request);
3317 lock_release(rtld_bind_lock, &lockstate);
3323 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3326 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3327 phdr_info->dlpi_name = obj->path;
3328 phdr_info->dlpi_phdr = obj->phdr;
3329 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3330 phdr_info->dlpi_tls_modid = obj->tlsindex;
3331 phdr_info->dlpi_tls_data = obj->tlsinit;
3332 phdr_info->dlpi_adds = obj_loads;
3333 phdr_info->dlpi_subs = obj_loads - obj_count;
3337 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3339 struct dl_phdr_info phdr_info;
3340 const Obj_Entry *obj;
3341 RtldLockState bind_lockstate, phdr_lockstate;
3344 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3345 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3349 for (obj = obj_list; obj != NULL; obj = obj->next) {
3350 rtld_fill_dl_phdr_info(obj, &phdr_info);
3351 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3355 lock_release(rtld_bind_lock, &bind_lockstate);
3356 lock_release(rtld_phdr_lock, &phdr_lockstate);
3362 fill_search_info(const char *dir, size_t dirlen, void *param)
3364 struct fill_search_info_args *arg;
3368 if (arg->request == RTLD_DI_SERINFOSIZE) {
3369 arg->serinfo->dls_cnt ++;
3370 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3372 struct dl_serpath *s_entry;
3374 s_entry = arg->serpath;
3375 s_entry->dls_name = arg->strspace;
3376 s_entry->dls_flags = arg->flags;
3378 strncpy(arg->strspace, dir, dirlen);
3379 arg->strspace[dirlen] = '\0';
3381 arg->strspace += dirlen + 1;
3389 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3391 struct dl_serinfo _info;
3392 struct fill_search_info_args args;
3394 args.request = RTLD_DI_SERINFOSIZE;
3395 args.serinfo = &_info;
3397 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3400 path_enumerate(obj->rpath, fill_search_info, &args);
3401 path_enumerate(ld_library_path, fill_search_info, &args);
3402 path_enumerate(obj->runpath, fill_search_info, &args);
3403 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3404 if (!obj->z_nodeflib)
3405 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3408 if (request == RTLD_DI_SERINFOSIZE) {
3409 info->dls_size = _info.dls_size;
3410 info->dls_cnt = _info.dls_cnt;
3414 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3415 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3419 args.request = RTLD_DI_SERINFO;
3420 args.serinfo = info;
3421 args.serpath = &info->dls_serpath[0];
3422 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3424 args.flags = LA_SER_RUNPATH;
3425 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3428 args.flags = LA_SER_LIBPATH;
3429 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3432 args.flags = LA_SER_RUNPATH;
3433 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3436 args.flags = LA_SER_CONFIG;
3437 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3441 args.flags = LA_SER_DEFAULT;
3442 if (!obj->z_nodeflib &&
3443 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3449 rtld_dirname(const char *path, char *bname)
3453 /* Empty or NULL string gets treated as "." */
3454 if (path == NULL || *path == '\0') {
3460 /* Strip trailing slashes */
3461 endp = path + strlen(path) - 1;
3462 while (endp > path && *endp == '/')
3465 /* Find the start of the dir */
3466 while (endp > path && *endp != '/')
3469 /* Either the dir is "/" or there are no slashes */
3471 bname[0] = *endp == '/' ? '/' : '.';
3477 } while (endp > path && *endp == '/');
3480 if (endp - path + 2 > PATH_MAX)
3482 _rtld_error("Filename is too long: %s", path);
3486 strncpy(bname, path, endp - path + 1);
3487 bname[endp - path + 1] = '\0';
3492 rtld_dirname_abs(const char *path, char *base)
3496 if (realpath(path, base) == NULL)
3498 dbg("%s -> %s", path, base);
3499 last = strrchr(base, '/');
3508 linkmap_add(Obj_Entry *obj)
3510 struct link_map *l = &obj->linkmap;
3511 struct link_map *prev;
3513 obj->linkmap.l_name = obj->path;
3514 obj->linkmap.l_addr = obj->mapbase;
3515 obj->linkmap.l_ld = obj->dynamic;
3517 /* GDB needs load offset on MIPS to use the symbols */
3518 obj->linkmap.l_offs = obj->relocbase;
3521 if (r_debug.r_map == NULL) {
3527 * Scan to the end of the list, but not past the entry for the
3528 * dynamic linker, which we want to keep at the very end.
3530 for (prev = r_debug.r_map;
3531 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3532 prev = prev->l_next)
3535 /* Link in the new entry. */
3537 l->l_next = prev->l_next;
3538 if (l->l_next != NULL)
3539 l->l_next->l_prev = l;
3544 linkmap_delete(Obj_Entry *obj)
3546 struct link_map *l = &obj->linkmap;
3548 if (l->l_prev == NULL) {
3549 if ((r_debug.r_map = l->l_next) != NULL)
3550 l->l_next->l_prev = NULL;
3554 if ((l->l_prev->l_next = l->l_next) != NULL)
3555 l->l_next->l_prev = l->l_prev;
3559 * Function for the debugger to set a breakpoint on to gain control.
3561 * The two parameters allow the debugger to easily find and determine
3562 * what the runtime loader is doing and to whom it is doing it.
3564 * When the loadhook trap is hit (r_debug_state, set at program
3565 * initialization), the arguments can be found on the stack:
3567 * +8 struct link_map *m
3568 * +4 struct r_debug *rd
3572 r_debug_state(struct r_debug* rd, struct link_map *m)
3575 * The following is a hack to force the compiler to emit calls to
3576 * this function, even when optimizing. If the function is empty,
3577 * the compiler is not obliged to emit any code for calls to it,
3578 * even when marked __noinline. However, gdb depends on those
3581 __compiler_membar();
3585 * A function called after init routines have completed. This can be used to
3586 * break before a program's entry routine is called, and can be used when
3587 * main is not available in the symbol table.
3590 _r_debug_postinit(struct link_map *m)
3593 /* See r_debug_state(). */
3594 __compiler_membar();
3598 * Get address of the pointer variable in the main program.
3599 * Prefer non-weak symbol over the weak one.
3601 static const void **
3602 get_program_var_addr(const char *name, RtldLockState *lockstate)
3607 symlook_init(&req, name);
3608 req.lockstate = lockstate;
3609 donelist_init(&donelist);
3610 if (symlook_global(&req, &donelist) != 0)
3612 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3613 return ((const void **)make_function_pointer(req.sym_out,
3615 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3616 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3618 return ((const void **)(req.defobj_out->relocbase +
3619 req.sym_out->st_value));
3623 * Set a pointer variable in the main program to the given value. This
3624 * is used to set key variables such as "environ" before any of the
3625 * init functions are called.
3628 set_program_var(const char *name, const void *value)
3632 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3633 dbg("\"%s\": *%p <-- %p", name, addr, value);
3639 * Search the global objects, including dependencies and main object,
3640 * for the given symbol.
3643 symlook_global(SymLook *req, DoneList *donelist)
3646 const Objlist_Entry *elm;
3649 symlook_init_from_req(&req1, req);
3651 /* Search all objects loaded at program start up. */
3652 if (req->defobj_out == NULL ||
3653 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3654 res = symlook_list(&req1, &list_main, donelist);
3655 if (res == 0 && (req->defobj_out == NULL ||
3656 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3657 req->sym_out = req1.sym_out;
3658 req->defobj_out = req1.defobj_out;
3659 assert(req->defobj_out != NULL);
3663 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3664 STAILQ_FOREACH(elm, &list_global, link) {
3665 if (req->defobj_out != NULL &&
3666 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3668 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3669 if (res == 0 && (req->defobj_out == NULL ||
3670 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3671 req->sym_out = req1.sym_out;
3672 req->defobj_out = req1.defobj_out;
3673 assert(req->defobj_out != NULL);
3677 return (req->sym_out != NULL ? 0 : ESRCH);
3681 * Given a symbol name in a referencing object, find the corresponding
3682 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3683 * no definition was found. Returns a pointer to the Obj_Entry of the
3684 * defining object via the reference parameter DEFOBJ_OUT.
3687 symlook_default(SymLook *req, const Obj_Entry *refobj)
3690 const Objlist_Entry *elm;
3694 donelist_init(&donelist);
3695 symlook_init_from_req(&req1, req);
3697 /* Look first in the referencing object if linked symbolically. */
3698 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3699 res = symlook_obj(&req1, refobj);
3701 req->sym_out = req1.sym_out;
3702 req->defobj_out = req1.defobj_out;
3703 assert(req->defobj_out != NULL);
3707 symlook_global(req, &donelist);
3709 /* Search all dlopened DAGs containing the referencing object. */
3710 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3711 if (req->sym_out != NULL &&
3712 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3714 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3715 if (res == 0 && (req->sym_out == NULL ||
3716 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3717 req->sym_out = req1.sym_out;
3718 req->defobj_out = req1.defobj_out;
3719 assert(req->defobj_out != NULL);
3724 * Search the dynamic linker itself, and possibly resolve the
3725 * symbol from there. This is how the application links to
3726 * dynamic linker services such as dlopen.
3728 if (req->sym_out == NULL ||
3729 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3730 res = symlook_obj(&req1, &obj_rtld);
3732 req->sym_out = req1.sym_out;
3733 req->defobj_out = req1.defobj_out;
3734 assert(req->defobj_out != NULL);
3738 return (req->sym_out != NULL ? 0 : ESRCH);
3742 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3745 const Obj_Entry *defobj;
3746 const Objlist_Entry *elm;
3752 STAILQ_FOREACH(elm, objlist, link) {
3753 if (donelist_check(dlp, elm->obj))
3755 symlook_init_from_req(&req1, req);
3756 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3757 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3759 defobj = req1.defobj_out;
3760 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3767 req->defobj_out = defobj;
3774 * Search the chain of DAGS cointed to by the given Needed_Entry
3775 * for a symbol of the given name. Each DAG is scanned completely
3776 * before advancing to the next one. Returns a pointer to the symbol,
3777 * or NULL if no definition was found.
3780 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3783 const Needed_Entry *n;
3784 const Obj_Entry *defobj;
3790 symlook_init_from_req(&req1, req);
3791 for (n = needed; n != NULL; n = n->next) {
3792 if (n->obj == NULL ||
3793 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3795 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3797 defobj = req1.defobj_out;
3798 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3804 req->defobj_out = defobj;
3811 * Search the symbol table of a single shared object for a symbol of
3812 * the given name and version, if requested. Returns a pointer to the
3813 * symbol, or NULL if no definition was found. If the object is
3814 * filter, return filtered symbol from filtee.
3816 * The symbol's hash value is passed in for efficiency reasons; that
3817 * eliminates many recomputations of the hash value.
3820 symlook_obj(SymLook *req, const Obj_Entry *obj)
3824 int flags, res, mres;
3827 * If there is at least one valid hash at this point, we prefer to
3828 * use the faster GNU version if available.
3830 if (obj->valid_hash_gnu)
3831 mres = symlook_obj1_gnu(req, obj);
3832 else if (obj->valid_hash_sysv)
3833 mres = symlook_obj1_sysv(req, obj);
3838 if (obj->needed_filtees != NULL) {
3839 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3840 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3841 donelist_init(&donelist);
3842 symlook_init_from_req(&req1, req);
3843 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3845 req->sym_out = req1.sym_out;
3846 req->defobj_out = req1.defobj_out;
3850 if (obj->needed_aux_filtees != NULL) {
3851 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3852 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3853 donelist_init(&donelist);
3854 symlook_init_from_req(&req1, req);
3855 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3857 req->sym_out = req1.sym_out;
3858 req->defobj_out = req1.defobj_out;
3866 /* Symbol match routine common to both hash functions */
3868 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3869 const unsigned long symnum)
3872 const Elf_Sym *symp;
3875 symp = obj->symtab + symnum;
3876 strp = obj->strtab + symp->st_name;
3878 switch (ELF_ST_TYPE(symp->st_info)) {
3884 if (symp->st_value == 0)
3888 if (symp->st_shndx != SHN_UNDEF)
3891 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3892 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3899 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3902 if (req->ventry == NULL) {
3903 if (obj->versyms != NULL) {
3904 verndx = VER_NDX(obj->versyms[symnum]);
3905 if (verndx > obj->vernum) {
3907 "%s: symbol %s references wrong version %d",
3908 obj->path, obj->strtab + symnum, verndx);
3912 * If we are not called from dlsym (i.e. this
3913 * is a normal relocation from unversioned
3914 * binary), accept the symbol immediately if
3915 * it happens to have first version after this
3916 * shared object became versioned. Otherwise,
3917 * if symbol is versioned and not hidden,
3918 * remember it. If it is the only symbol with
3919 * this name exported by the shared object, it
3920 * will be returned as a match by the calling
3921 * function. If symbol is global (verndx < 2)
3922 * accept it unconditionally.
3924 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3925 verndx == VER_NDX_GIVEN) {
3926 result->sym_out = symp;
3929 else if (verndx >= VER_NDX_GIVEN) {
3930 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
3932 if (result->vsymp == NULL)
3933 result->vsymp = symp;
3939 result->sym_out = symp;
3942 if (obj->versyms == NULL) {
3943 if (object_match_name(obj, req->ventry->name)) {
3944 _rtld_error("%s: object %s should provide version %s "
3945 "for symbol %s", obj_rtld.path, obj->path,
3946 req->ventry->name, obj->strtab + symnum);
3950 verndx = VER_NDX(obj->versyms[symnum]);
3951 if (verndx > obj->vernum) {
3952 _rtld_error("%s: symbol %s references wrong version %d",
3953 obj->path, obj->strtab + symnum, verndx);
3956 if (obj->vertab[verndx].hash != req->ventry->hash ||
3957 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3959 * Version does not match. Look if this is a
3960 * global symbol and if it is not hidden. If
3961 * global symbol (verndx < 2) is available,
3962 * use it. Do not return symbol if we are
3963 * called by dlvsym, because dlvsym looks for
3964 * a specific version and default one is not
3965 * what dlvsym wants.
3967 if ((req->flags & SYMLOOK_DLSYM) ||
3968 (verndx >= VER_NDX_GIVEN) ||
3969 (obj->versyms[symnum] & VER_NDX_HIDDEN))
3973 result->sym_out = symp;
3978 * Search for symbol using SysV hash function.
3979 * obj->buckets is known not to be NULL at this point; the test for this was
3980 * performed with the obj->valid_hash_sysv assignment.
3983 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
3985 unsigned long symnum;
3986 Sym_Match_Result matchres;
3988 matchres.sym_out = NULL;
3989 matchres.vsymp = NULL;
3990 matchres.vcount = 0;
3992 for (symnum = obj->buckets[req->hash % obj->nbuckets];
3993 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
3994 if (symnum >= obj->nchains)
3995 return (ESRCH); /* Bad object */
3997 if (matched_symbol(req, obj, &matchres, symnum)) {
3998 req->sym_out = matchres.sym_out;
3999 req->defobj_out = obj;
4003 if (matchres.vcount == 1) {
4004 req->sym_out = matchres.vsymp;
4005 req->defobj_out = obj;
4011 /* Search for symbol using GNU hash function */
4013 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4015 Elf_Addr bloom_word;
4016 const Elf32_Word *hashval;
4018 Sym_Match_Result matchres;
4019 unsigned int h1, h2;
4020 unsigned long symnum;
4022 matchres.sym_out = NULL;
4023 matchres.vsymp = NULL;
4024 matchres.vcount = 0;
4026 /* Pick right bitmask word from Bloom filter array */
4027 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4028 obj->maskwords_bm_gnu];
4030 /* Calculate modulus word size of gnu hash and its derivative */
4031 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4032 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4034 /* Filter out the "definitely not in set" queries */
4035 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4038 /* Locate hash chain and corresponding value element*/
4039 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4042 hashval = &obj->chain_zero_gnu[bucket];
4044 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4045 symnum = hashval - obj->chain_zero_gnu;
4046 if (matched_symbol(req, obj, &matchres, symnum)) {
4047 req->sym_out = matchres.sym_out;
4048 req->defobj_out = obj;
4052 } while ((*hashval++ & 1) == 0);
4053 if (matchres.vcount == 1) {
4054 req->sym_out = matchres.vsymp;
4055 req->defobj_out = obj;
4062 trace_loaded_objects(Obj_Entry *obj)
4064 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4067 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
4070 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
4071 fmt1 = "\t%o => %p (%x)\n";
4073 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
4074 fmt2 = "\t%o (%x)\n";
4076 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
4078 for (; obj; obj = obj->next) {
4079 Needed_Entry *needed;
4083 if (list_containers && obj->needed != NULL)
4084 rtld_printf("%s:\n", obj->path);
4085 for (needed = obj->needed; needed; needed = needed->next) {
4086 if (needed->obj != NULL) {
4087 if (needed->obj->traced && !list_containers)
4089 needed->obj->traced = true;
4090 path = needed->obj->path;
4094 name = (char *)obj->strtab + needed->name;
4095 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4097 fmt = is_lib ? fmt1 : fmt2;
4098 while ((c = *fmt++) != '\0') {
4124 rtld_putstr(main_local);
4127 rtld_putstr(obj_main->path);
4134 rtld_printf("%d", sodp->sod_major);
4137 rtld_printf("%d", sodp->sod_minor);
4144 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4157 * Unload a dlopened object and its dependencies from memory and from
4158 * our data structures. It is assumed that the DAG rooted in the
4159 * object has already been unreferenced, and that the object has a
4160 * reference count of 0.
4163 unload_object(Obj_Entry *root)
4168 assert(root->refcount == 0);
4171 * Pass over the DAG removing unreferenced objects from
4172 * appropriate lists.
4174 unlink_object(root);
4176 /* Unmap all objects that are no longer referenced. */
4177 linkp = &obj_list->next;
4178 while ((obj = *linkp) != NULL) {
4179 if (obj->refcount == 0) {
4180 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4182 dbg("unloading \"%s\"", obj->path);
4183 unload_filtees(root);
4184 munmap(obj->mapbase, obj->mapsize);
4185 linkmap_delete(obj);
4196 unlink_object(Obj_Entry *root)
4200 if (root->refcount == 0) {
4201 /* Remove the object from the RTLD_GLOBAL list. */
4202 objlist_remove(&list_global, root);
4204 /* Remove the object from all objects' DAG lists. */
4205 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4206 objlist_remove(&elm->obj->dldags, root);
4207 if (elm->obj != root)
4208 unlink_object(elm->obj);
4214 ref_dag(Obj_Entry *root)
4218 assert(root->dag_inited);
4219 STAILQ_FOREACH(elm, &root->dagmembers, link)
4220 elm->obj->refcount++;
4224 unref_dag(Obj_Entry *root)
4228 assert(root->dag_inited);
4229 STAILQ_FOREACH(elm, &root->dagmembers, link)
4230 elm->obj->refcount--;
4234 * Common code for MD __tls_get_addr().
4236 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4238 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4240 Elf_Addr *newdtv, *dtv;
4241 RtldLockState lockstate;
4245 /* Check dtv generation in case new modules have arrived */
4246 if (dtv[0] != tls_dtv_generation) {
4247 wlock_acquire(rtld_bind_lock, &lockstate);
4248 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4250 if (to_copy > tls_max_index)
4251 to_copy = tls_max_index;
4252 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4253 newdtv[0] = tls_dtv_generation;
4254 newdtv[1] = tls_max_index;
4256 lock_release(rtld_bind_lock, &lockstate);
4257 dtv = *dtvp = newdtv;
4260 /* Dynamically allocate module TLS if necessary */
4261 if (dtv[index + 1] == 0) {
4262 /* Signal safe, wlock will block out signals. */
4263 wlock_acquire(rtld_bind_lock, &lockstate);
4264 if (!dtv[index + 1])
4265 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4266 lock_release(rtld_bind_lock, &lockstate);
4268 return ((void *)(dtv[index + 1] + offset));
4272 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4277 /* Check dtv generation in case new modules have arrived */
4278 if (__predict_true(dtv[0] == tls_dtv_generation &&
4279 dtv[index + 1] != 0))
4280 return ((void *)(dtv[index + 1] + offset));
4281 return (tls_get_addr_slow(dtvp, index, offset));
4284 #if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__)
4287 * Allocate Static TLS using the Variant I method.
4290 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4299 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4302 assert(tcbsize >= TLS_TCB_SIZE);
4303 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4304 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4306 if (oldtcb != NULL) {
4307 memcpy(tls, oldtcb, tls_static_space);
4310 /* Adjust the DTV. */
4312 for (i = 0; i < dtv[1]; i++) {
4313 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4314 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4315 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4319 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4321 dtv[0] = tls_dtv_generation;
4322 dtv[1] = tls_max_index;
4324 for (obj = objs; obj; obj = obj->next) {
4325 if (obj->tlsoffset > 0) {
4326 addr = (Elf_Addr)tls + obj->tlsoffset;
4327 if (obj->tlsinitsize > 0)
4328 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4329 if (obj->tlssize > obj->tlsinitsize)
4330 memset((void*) (addr + obj->tlsinitsize), 0,
4331 obj->tlssize - obj->tlsinitsize);
4332 dtv[obj->tlsindex + 1] = addr;
4341 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4344 Elf_Addr tlsstart, tlsend;
4347 assert(tcbsize >= TLS_TCB_SIZE);
4349 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4350 tlsend = tlsstart + tls_static_space;
4352 dtv = *(Elf_Addr **)tlsstart;
4354 for (i = 0; i < dtvsize; i++) {
4355 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4356 free((void*)dtv[i+2]);
4365 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4368 * Allocate Static TLS using the Variant II method.
4371 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4374 size_t size, ralign;
4376 Elf_Addr *dtv, *olddtv;
4377 Elf_Addr segbase, oldsegbase, addr;
4381 if (tls_static_max_align > ralign)
4382 ralign = tls_static_max_align;
4383 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4385 assert(tcbsize >= 2*sizeof(Elf_Addr));
4386 tls = malloc_aligned(size, ralign);
4387 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4389 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4390 ((Elf_Addr*)segbase)[0] = segbase;
4391 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4393 dtv[0] = tls_dtv_generation;
4394 dtv[1] = tls_max_index;
4398 * Copy the static TLS block over whole.
4400 oldsegbase = (Elf_Addr) oldtls;
4401 memcpy((void *)(segbase - tls_static_space),
4402 (const void *)(oldsegbase - tls_static_space),
4406 * If any dynamic TLS blocks have been created tls_get_addr(),
4409 olddtv = ((Elf_Addr**)oldsegbase)[1];
4410 for (i = 0; i < olddtv[1]; i++) {
4411 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4412 dtv[i+2] = olddtv[i+2];
4418 * We assume that this block was the one we created with
4419 * allocate_initial_tls().
4421 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4423 for (obj = objs; obj; obj = obj->next) {
4424 if (obj->tlsoffset) {
4425 addr = segbase - obj->tlsoffset;
4426 memset((void*) (addr + obj->tlsinitsize),
4427 0, obj->tlssize - obj->tlsinitsize);
4429 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4430 dtv[obj->tlsindex + 1] = addr;
4435 return (void*) segbase;
4439 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4442 size_t size, ralign;
4444 Elf_Addr tlsstart, tlsend;
4447 * Figure out the size of the initial TLS block so that we can
4448 * find stuff which ___tls_get_addr() allocated dynamically.
4451 if (tls_static_max_align > ralign)
4452 ralign = tls_static_max_align;
4453 size = round(tls_static_space, ralign);
4455 dtv = ((Elf_Addr**)tls)[1];
4457 tlsend = (Elf_Addr) tls;
4458 tlsstart = tlsend - size;
4459 for (i = 0; i < dtvsize; i++) {
4460 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4461 free_aligned((void *)dtv[i + 2]);
4465 free_aligned((void *)tlsstart);
4472 * Allocate TLS block for module with given index.
4475 allocate_module_tls(int index)
4480 for (obj = obj_list; obj; obj = obj->next) {
4481 if (obj->tlsindex == index)
4485 _rtld_error("Can't find module with TLS index %d", index);
4489 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4490 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4491 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4497 allocate_tls_offset(Obj_Entry *obj)
4504 if (obj->tlssize == 0) {
4505 obj->tls_done = true;
4509 if (obj->tlsindex == 1)
4510 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4512 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4513 obj->tlssize, obj->tlsalign);
4516 * If we have already fixed the size of the static TLS block, we
4517 * must stay within that size. When allocating the static TLS, we
4518 * leave a small amount of space spare to be used for dynamically
4519 * loading modules which use static TLS.
4521 if (tls_static_space != 0) {
4522 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4524 } else if (obj->tlsalign > tls_static_max_align) {
4525 tls_static_max_align = obj->tlsalign;
4528 tls_last_offset = obj->tlsoffset = off;
4529 tls_last_size = obj->tlssize;
4530 obj->tls_done = true;
4536 free_tls_offset(Obj_Entry *obj)
4540 * If we were the last thing to allocate out of the static TLS
4541 * block, we give our space back to the 'allocator'. This is a
4542 * simplistic workaround to allow libGL.so.1 to be loaded and
4543 * unloaded multiple times.
4545 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4546 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4547 tls_last_offset -= obj->tlssize;
4553 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4556 RtldLockState lockstate;
4558 wlock_acquire(rtld_bind_lock, &lockstate);
4559 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4560 lock_release(rtld_bind_lock, &lockstate);
4565 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4567 RtldLockState lockstate;
4569 wlock_acquire(rtld_bind_lock, &lockstate);
4570 free_tls(tcb, tcbsize, tcbalign);
4571 lock_release(rtld_bind_lock, &lockstate);
4575 object_add_name(Obj_Entry *obj, const char *name)
4581 entry = malloc(sizeof(Name_Entry) + len);
4583 if (entry != NULL) {
4584 strcpy(entry->name, name);
4585 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4590 object_match_name(const Obj_Entry *obj, const char *name)
4594 STAILQ_FOREACH(entry, &obj->names, link) {
4595 if (strcmp(name, entry->name) == 0)
4602 locate_dependency(const Obj_Entry *obj, const char *name)
4604 const Objlist_Entry *entry;
4605 const Needed_Entry *needed;
4607 STAILQ_FOREACH(entry, &list_main, link) {
4608 if (object_match_name(entry->obj, name))
4612 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4613 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4614 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4616 * If there is DT_NEEDED for the name we are looking for,
4617 * we are all set. Note that object might not be found if
4618 * dependency was not loaded yet, so the function can
4619 * return NULL here. This is expected and handled
4620 * properly by the caller.
4622 return (needed->obj);
4625 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4631 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4632 const Elf_Vernaux *vna)
4634 const Elf_Verdef *vd;
4635 const char *vername;
4637 vername = refobj->strtab + vna->vna_name;
4638 vd = depobj->verdef;
4640 _rtld_error("%s: version %s required by %s not defined",
4641 depobj->path, vername, refobj->path);
4645 if (vd->vd_version != VER_DEF_CURRENT) {
4646 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4647 depobj->path, vd->vd_version);
4650 if (vna->vna_hash == vd->vd_hash) {
4651 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4652 ((char *)vd + vd->vd_aux);
4653 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4656 if (vd->vd_next == 0)
4658 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4660 if (vna->vna_flags & VER_FLG_WEAK)
4662 _rtld_error("%s: version %s required by %s not found",
4663 depobj->path, vername, refobj->path);
4668 rtld_verify_object_versions(Obj_Entry *obj)
4670 const Elf_Verneed *vn;
4671 const Elf_Verdef *vd;
4672 const Elf_Verdaux *vda;
4673 const Elf_Vernaux *vna;
4674 const Obj_Entry *depobj;
4675 int maxvernum, vernum;
4677 if (obj->ver_checked)
4679 obj->ver_checked = true;
4683 * Walk over defined and required version records and figure out
4684 * max index used by any of them. Do very basic sanity checking
4688 while (vn != NULL) {
4689 if (vn->vn_version != VER_NEED_CURRENT) {
4690 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4691 obj->path, vn->vn_version);
4694 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4696 vernum = VER_NEED_IDX(vna->vna_other);
4697 if (vernum > maxvernum)
4699 if (vna->vna_next == 0)
4701 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4703 if (vn->vn_next == 0)
4705 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4709 while (vd != NULL) {
4710 if (vd->vd_version != VER_DEF_CURRENT) {
4711 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4712 obj->path, vd->vd_version);
4715 vernum = VER_DEF_IDX(vd->vd_ndx);
4716 if (vernum > maxvernum)
4718 if (vd->vd_next == 0)
4720 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4727 * Store version information in array indexable by version index.
4728 * Verify that object version requirements are satisfied along the
4731 obj->vernum = maxvernum + 1;
4732 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4735 while (vd != NULL) {
4736 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4737 vernum = VER_DEF_IDX(vd->vd_ndx);
4738 assert(vernum <= maxvernum);
4739 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4740 obj->vertab[vernum].hash = vd->vd_hash;
4741 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4742 obj->vertab[vernum].file = NULL;
4743 obj->vertab[vernum].flags = 0;
4745 if (vd->vd_next == 0)
4747 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4751 while (vn != NULL) {
4752 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4755 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4757 if (check_object_provided_version(obj, depobj, vna))
4759 vernum = VER_NEED_IDX(vna->vna_other);
4760 assert(vernum <= maxvernum);
4761 obj->vertab[vernum].hash = vna->vna_hash;
4762 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4763 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4764 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4765 VER_INFO_HIDDEN : 0;
4766 if (vna->vna_next == 0)
4768 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4770 if (vn->vn_next == 0)
4772 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4778 rtld_verify_versions(const Objlist *objlist)
4780 Objlist_Entry *entry;
4784 STAILQ_FOREACH(entry, objlist, link) {
4786 * Skip dummy objects or objects that have their version requirements
4789 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4791 if (rtld_verify_object_versions(entry->obj) == -1) {
4793 if (ld_tracing == NULL)
4797 if (rc == 0 || ld_tracing != NULL)
4798 rc = rtld_verify_object_versions(&obj_rtld);
4803 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4808 vernum = VER_NDX(obj->versyms[symnum]);
4809 if (vernum >= obj->vernum) {
4810 _rtld_error("%s: symbol %s has wrong verneed value %d",
4811 obj->path, obj->strtab + symnum, vernum);
4812 } else if (obj->vertab[vernum].hash != 0) {
4813 return &obj->vertab[vernum];
4820 _rtld_get_stack_prot(void)
4823 return (stack_prot);
4827 _rtld_is_dlopened(void *arg)
4830 RtldLockState lockstate;
4833 rlock_acquire(rtld_bind_lock, &lockstate);
4836 obj = obj_from_addr(arg);
4838 _rtld_error("No shared object contains address");
4839 lock_release(rtld_bind_lock, &lockstate);
4842 res = obj->dlopened ? 1 : 0;
4843 lock_release(rtld_bind_lock, &lockstate);
4848 map_stacks_exec(RtldLockState *lockstate)
4850 void (*thr_map_stacks_exec)(void);
4852 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4854 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4855 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4856 if (thr_map_stacks_exec != NULL) {
4857 stack_prot |= PROT_EXEC;
4858 thr_map_stacks_exec();
4863 symlook_init(SymLook *dst, const char *name)
4866 bzero(dst, sizeof(*dst));
4868 dst->hash = elf_hash(name);
4869 dst->hash_gnu = gnu_hash(name);
4873 symlook_init_from_req(SymLook *dst, const SymLook *src)
4876 dst->name = src->name;
4877 dst->hash = src->hash;
4878 dst->hash_gnu = src->hash_gnu;
4879 dst->ventry = src->ventry;
4880 dst->flags = src->flags;
4881 dst->defobj_out = NULL;
4882 dst->sym_out = NULL;
4883 dst->lockstate = src->lockstate;
4887 * Overrides for libc_pic-provided functions.
4891 __getosreldate(void)
4901 oid[1] = KERN_OSRELDATE;
4903 len = sizeof(osrel);
4904 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4905 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4917 void (*__cleanup)(void);
4918 int __isthreaded = 0;
4919 int _thread_autoinit_dummy_decl = 1;
4922 * No unresolved symbols for rtld.
4925 __pthread_cxa_finalize(struct dl_phdr_info *a)
4930 __stack_chk_fail(void)
4933 _rtld_error("stack overflow detected; terminated");
4936 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
4942 _rtld_error("buffer overflow detected; terminated");
4947 rtld_strerror(int errnum)
4950 if (errnum < 0 || errnum >= sys_nerr)
4951 return ("Unknown error");
4952 return (sys_errlist[errnum]);