2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * Copyright 2009-2012 Konstantin Belousov <kib@FreeBSD.ORG>.
5 * Copyright 2012 John Marino <draco@marino.st>.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 * Dynamic linker for ELF.
34 * John Polstra <jdp@polstra.com>.
38 #error "GCC is needed to compile this file"
41 #include <sys/param.h>
42 #include <sys/mount.h>
45 #include <sys/sysctl.h>
47 #include <sys/utsname.h>
48 #include <sys/ktrace.h>
64 #include "rtld_printf.h"
68 #define PATH_RTLD "/libexec/ld-elf.so.1"
70 #define PATH_RTLD "/libexec/ld-elf32.so.1"
74 typedef void (*func_ptr_type)();
75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
78 * Function declarations.
80 static const char *basename(const char *);
81 static void die(void) __dead2;
82 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
83 const Elf_Dyn **, const Elf_Dyn **);
84 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
86 static void digest_dynamic(Obj_Entry *, int);
87 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
88 static Obj_Entry *dlcheck(void *);
89 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
90 int lo_flags, int mode, RtldLockState *lockstate);
91 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
92 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
93 static bool donelist_check(DoneList *, const Obj_Entry *);
94 static void errmsg_restore(char *);
95 static char *errmsg_save(void);
96 static void *fill_search_info(const char *, size_t, void *);
97 static char *find_library(const char *, const Obj_Entry *);
98 static const char *gethints(bool);
99 static void init_dag(Obj_Entry *);
100 static void init_rtld(caddr_t, Elf_Auxinfo **);
101 static void initlist_add_neededs(Needed_Entry *, Objlist *);
102 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
103 static void linkmap_add(Obj_Entry *);
104 static void linkmap_delete(Obj_Entry *);
105 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
106 static void unload_filtees(Obj_Entry *);
107 static int load_needed_objects(Obj_Entry *, int);
108 static int load_preload_objects(void);
109 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
110 static void map_stacks_exec(RtldLockState *);
111 static Obj_Entry *obj_from_addr(const void *);
112 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
113 static void objlist_call_init(Objlist *, RtldLockState *);
114 static void objlist_clear(Objlist *);
115 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
116 static void objlist_init(Objlist *);
117 static void objlist_push_head(Objlist *, Obj_Entry *);
118 static void objlist_push_tail(Objlist *, Obj_Entry *);
119 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
120 static void objlist_remove(Objlist *, Obj_Entry *);
121 static void *path_enumerate(const char *, path_enum_proc, void *);
122 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
123 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
124 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
125 int flags, RtldLockState *lockstate);
126 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
128 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
129 int flags, RtldLockState *lockstate);
130 static int rtld_dirname(const char *, char *);
131 static int rtld_dirname_abs(const char *, char *);
132 static void *rtld_dlopen(const char *name, int fd, int mode);
133 static void rtld_exit(void);
134 static char *search_library_path(const char *, const char *);
135 static const void **get_program_var_addr(const char *, RtldLockState *);
136 static void set_program_var(const char *, const void *);
137 static int symlook_default(SymLook *, const Obj_Entry *refobj);
138 static int symlook_global(SymLook *, DoneList *);
139 static void symlook_init_from_req(SymLook *, const SymLook *);
140 static int symlook_list(SymLook *, const Objlist *, DoneList *);
141 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
142 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
143 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
144 static void trace_loaded_objects(Obj_Entry *);
145 static void unlink_object(Obj_Entry *);
146 static void unload_object(Obj_Entry *);
147 static void unref_dag(Obj_Entry *);
148 static void ref_dag(Obj_Entry *);
149 static char *origin_subst_one(char *, const char *, const char *, bool);
150 static char *origin_subst(char *, const char *);
151 static void preinit_main(void);
152 static int rtld_verify_versions(const Objlist *);
153 static int rtld_verify_object_versions(Obj_Entry *);
154 static void object_add_name(Obj_Entry *, const char *);
155 static int object_match_name(const Obj_Entry *, const char *);
156 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
157 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
158 struct dl_phdr_info *phdr_info);
159 static uint32_t gnu_hash(const char *);
160 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
161 const unsigned long);
163 void r_debug_state(struct r_debug *, struct link_map *) __noinline;
168 static char *error_message; /* Message for dlerror(), or NULL */
169 struct r_debug r_debug; /* for GDB; */
170 static bool libmap_disable; /* Disable libmap */
171 static bool ld_loadfltr; /* Immediate filters processing */
172 static char *libmap_override; /* Maps to use in addition to libmap.conf */
173 static bool trust; /* False for setuid and setgid programs */
174 static bool dangerous_ld_env; /* True if environment variables have been
175 used to affect the libraries loaded */
176 static char *ld_bind_now; /* Environment variable for immediate binding */
177 static char *ld_debug; /* Environment variable for debugging */
178 static char *ld_library_path; /* Environment variable for search path */
179 static char *ld_preload; /* Environment variable for libraries to
181 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
182 static char *ld_tracing; /* Called from ldd to print libs */
183 static char *ld_utrace; /* Use utrace() to log events. */
184 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
185 static Obj_Entry **obj_tail; /* Link field of last object in list */
186 static Obj_Entry *obj_main; /* The main program shared object */
187 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
188 static unsigned int obj_count; /* Number of objects in obj_list */
189 static unsigned int obj_loads; /* Number of objects in obj_list */
191 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
192 STAILQ_HEAD_INITIALIZER(list_global);
193 static Objlist list_main = /* Objects loaded at program startup */
194 STAILQ_HEAD_INITIALIZER(list_main);
195 static Objlist list_fini = /* Objects needing fini() calls */
196 STAILQ_HEAD_INITIALIZER(list_fini);
198 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
200 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
202 extern Elf_Dyn _DYNAMIC;
203 #pragma weak _DYNAMIC
204 #ifndef RTLD_IS_DYNAMIC
205 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
208 int osreldate, pagesize;
210 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
212 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
213 static int max_stack_flags;
216 * Global declarations normally provided by crt1. The dynamic linker is
217 * not built with crt1, so we have to provide them ourselves.
223 * Used to pass argc, argv to init functions.
229 * Globals to control TLS allocation.
231 size_t tls_last_offset; /* Static TLS offset of last module */
232 size_t tls_last_size; /* Static TLS size of last module */
233 size_t tls_static_space; /* Static TLS space allocated */
234 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
235 int tls_max_index = 1; /* Largest module index allocated */
237 bool ld_library_path_rpath = true;
240 * Fill in a DoneList with an allocation large enough to hold all of
241 * the currently-loaded objects. Keep this as a macro since it calls
242 * alloca and we want that to occur within the scope of the caller.
244 #define donelist_init(dlp) \
245 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
246 assert((dlp)->objs != NULL), \
247 (dlp)->num_alloc = obj_count, \
250 #define UTRACE_DLOPEN_START 1
251 #define UTRACE_DLOPEN_STOP 2
252 #define UTRACE_DLCLOSE_START 3
253 #define UTRACE_DLCLOSE_STOP 4
254 #define UTRACE_LOAD_OBJECT 5
255 #define UTRACE_UNLOAD_OBJECT 6
256 #define UTRACE_ADD_RUNDEP 7
257 #define UTRACE_PRELOAD_FINISHED 8
258 #define UTRACE_INIT_CALL 9
259 #define UTRACE_FINI_CALL 10
262 char sig[4]; /* 'RTLD' */
265 void *mapbase; /* Used for 'parent' and 'init/fini' */
267 int refcnt; /* Used for 'mode' */
268 char name[MAXPATHLEN];
271 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
272 if (ld_utrace != NULL) \
273 ld_utrace_log(e, h, mb, ms, r, n); \
277 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
278 int refcnt, const char *name)
280 struct utrace_rtld ut;
288 ut.mapbase = mapbase;
289 ut.mapsize = mapsize;
291 bzero(ut.name, sizeof(ut.name));
293 strlcpy(ut.name, name, sizeof(ut.name));
294 utrace(&ut, sizeof(ut));
298 * Main entry point for dynamic linking. The first argument is the
299 * stack pointer. The stack is expected to be laid out as described
300 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
301 * Specifically, the stack pointer points to a word containing
302 * ARGC. Following that in the stack is a null-terminated sequence
303 * of pointers to argument strings. Then comes a null-terminated
304 * sequence of pointers to environment strings. Finally, there is a
305 * sequence of "auxiliary vector" entries.
307 * The second argument points to a place to store the dynamic linker's
308 * exit procedure pointer and the third to a place to store the main
311 * The return value is the main program's entry point.
314 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
316 Elf_Auxinfo *aux_info[AT_COUNT];
324 Objlist_Entry *entry;
326 Obj_Entry **preload_tail;
327 Obj_Entry *last_interposer;
329 RtldLockState lockstate;
330 char *library_path_rpath;
335 * On entry, the dynamic linker itself has not been relocated yet.
336 * Be very careful not to reference any global data until after
337 * init_rtld has returned. It is OK to reference file-scope statics
338 * and string constants, and to call static and global functions.
341 /* Find the auxiliary vector on the stack. */
344 sp += argc + 1; /* Skip over arguments and NULL terminator */
346 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
348 aux = (Elf_Auxinfo *) sp;
350 /* Digest the auxiliary vector. */
351 for (i = 0; i < AT_COUNT; i++)
353 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
354 if (auxp->a_type < AT_COUNT)
355 aux_info[auxp->a_type] = auxp;
358 /* Initialize and relocate ourselves. */
359 assert(aux_info[AT_BASE] != NULL);
360 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
362 __progname = obj_rtld.path;
363 argv0 = argv[0] != NULL ? argv[0] : "(null)";
368 if (aux_info[AT_CANARY] != NULL &&
369 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
370 i = aux_info[AT_CANARYLEN]->a_un.a_val;
371 if (i > sizeof(__stack_chk_guard))
372 i = sizeof(__stack_chk_guard);
373 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
378 len = sizeof(__stack_chk_guard);
379 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
380 len != sizeof(__stack_chk_guard)) {
381 /* If sysctl was unsuccessful, use the "terminator canary". */
382 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
383 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
384 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
385 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
389 trust = !issetugid();
391 ld_bind_now = getenv(LD_ "BIND_NOW");
393 * If the process is tainted, then we un-set the dangerous environment
394 * variables. The process will be marked as tainted until setuid(2)
395 * is called. If any child process calls setuid(2) we do not want any
396 * future processes to honor the potentially un-safe variables.
399 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
400 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") ||
401 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
402 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) {
403 _rtld_error("environment corrupt; aborting");
407 ld_debug = getenv(LD_ "DEBUG");
408 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
409 libmap_override = getenv(LD_ "LIBMAP");
410 ld_library_path = getenv(LD_ "LIBRARY_PATH");
411 ld_preload = getenv(LD_ "PRELOAD");
412 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
413 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
414 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH");
415 if (library_path_rpath != NULL) {
416 if (library_path_rpath[0] == 'y' ||
417 library_path_rpath[0] == 'Y' ||
418 library_path_rpath[0] == '1')
419 ld_library_path_rpath = true;
421 ld_library_path_rpath = false;
423 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
424 (ld_library_path != NULL) || (ld_preload != NULL) ||
425 (ld_elf_hints_path != NULL) || ld_loadfltr;
426 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
427 ld_utrace = getenv(LD_ "UTRACE");
429 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
430 ld_elf_hints_path = _PATH_ELF_HINTS;
432 if (ld_debug != NULL && *ld_debug != '\0')
434 dbg("%s is initialized, base address = %p", __progname,
435 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
436 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
437 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
439 dbg("initializing thread locks");
443 * Load the main program, or process its program header if it is
446 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
447 int fd = aux_info[AT_EXECFD]->a_un.a_val;
448 dbg("loading main program");
449 obj_main = map_object(fd, argv0, NULL);
451 if (obj_main == NULL)
453 max_stack_flags = obj->stack_flags;
454 } else { /* Main program already loaded. */
455 const Elf_Phdr *phdr;
459 dbg("processing main program's program header");
460 assert(aux_info[AT_PHDR] != NULL);
461 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
462 assert(aux_info[AT_PHNUM] != NULL);
463 phnum = aux_info[AT_PHNUM]->a_un.a_val;
464 assert(aux_info[AT_PHENT] != NULL);
465 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
466 assert(aux_info[AT_ENTRY] != NULL);
467 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
468 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
472 if (aux_info[AT_EXECPATH] != 0) {
474 char buf[MAXPATHLEN];
476 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
477 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
478 if (kexecpath[0] == '/')
479 obj_main->path = kexecpath;
480 else if (getcwd(buf, sizeof(buf)) == NULL ||
481 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
482 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
483 obj_main->path = xstrdup(argv0);
485 obj_main->path = xstrdup(buf);
487 dbg("No AT_EXECPATH");
488 obj_main->path = xstrdup(argv0);
490 dbg("obj_main path %s", obj_main->path);
491 obj_main->mainprog = true;
493 if (aux_info[AT_STACKPROT] != NULL &&
494 aux_info[AT_STACKPROT]->a_un.a_val != 0)
495 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
498 * Get the actual dynamic linker pathname from the executable if
499 * possible. (It should always be possible.) That ensures that
500 * gdb will find the right dynamic linker even if a non-standard
503 if (obj_main->interp != NULL &&
504 strcmp(obj_main->interp, obj_rtld.path) != 0) {
506 obj_rtld.path = xstrdup(obj_main->interp);
507 __progname = obj_rtld.path;
510 digest_dynamic(obj_main, 0);
511 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
512 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
513 obj_main->dynsymcount);
515 linkmap_add(obj_main);
516 linkmap_add(&obj_rtld);
518 /* Link the main program into the list of objects. */
519 *obj_tail = obj_main;
520 obj_tail = &obj_main->next;
524 /* Initialize a fake symbol for resolving undefined weak references. */
525 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
526 sym_zero.st_shndx = SHN_UNDEF;
527 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
530 libmap_disable = (bool)lm_init(libmap_override);
532 dbg("loading LD_PRELOAD libraries");
533 if (load_preload_objects() == -1)
535 preload_tail = obj_tail;
537 dbg("loading needed objects");
538 if (load_needed_objects(obj_main, 0) == -1)
541 /* Make a list of all objects loaded at startup. */
542 last_interposer = obj_main;
543 for (obj = obj_list; obj != NULL; obj = obj->next) {
544 if (obj->z_interpose && obj != obj_main) {
545 objlist_put_after(&list_main, last_interposer, obj);
546 last_interposer = obj;
548 objlist_push_tail(&list_main, obj);
553 dbg("checking for required versions");
554 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
557 if (ld_tracing) { /* We're done */
558 trace_loaded_objects(obj_main);
562 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
563 dump_relocations(obj_main);
568 * Processing tls relocations requires having the tls offsets
569 * initialized. Prepare offsets before starting initial
570 * relocation processing.
572 dbg("initializing initial thread local storage offsets");
573 STAILQ_FOREACH(entry, &list_main, link) {
575 * Allocate all the initial objects out of the static TLS
576 * block even if they didn't ask for it.
578 allocate_tls_offset(entry->obj);
581 if (relocate_objects(obj_main,
582 ld_bind_now != NULL && *ld_bind_now != '\0',
583 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
586 dbg("doing copy relocations");
587 if (do_copy_relocations(obj_main) == -1)
590 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
591 dump_relocations(obj_main);
596 * Setup TLS for main thread. This must be done after the
597 * relocations are processed, since tls initialization section
598 * might be the subject for relocations.
600 dbg("initializing initial thread local storage");
601 allocate_initial_tls(obj_list);
603 dbg("initializing key program variables");
604 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
605 set_program_var("environ", env);
606 set_program_var("__elf_aux_vector", aux);
608 /* Make a list of init functions to call. */
609 objlist_init(&initlist);
610 initlist_add_objects(obj_list, preload_tail, &initlist);
612 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
614 map_stacks_exec(NULL);
616 dbg("resolving ifuncs");
617 if (resolve_objects_ifunc(obj_main,
618 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
622 if (!obj_main->crt_no_init) {
624 * Make sure we don't call the main program's init and fini
625 * functions for binaries linked with old crt1 which calls
628 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
629 obj_main->preinit_array = obj_main->init_array =
630 obj_main->fini_array = (Elf_Addr)NULL;
633 wlock_acquire(rtld_bind_lock, &lockstate);
634 if (obj_main->crt_no_init)
636 objlist_call_init(&initlist, &lockstate);
637 objlist_clear(&initlist);
638 dbg("loading filtees");
639 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
640 if (ld_loadfltr || obj->z_loadfltr)
641 load_filtees(obj, 0, &lockstate);
643 lock_release(rtld_bind_lock, &lockstate);
645 dbg("transferring control to program entry point = %p", obj_main->entry);
647 /* Return the exit procedure and the program entry point. */
648 *exit_proc = rtld_exit;
650 return (func_ptr_type) obj_main->entry;
654 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
659 ptr = (void *)make_function_pointer(def, obj);
660 target = ((Elf_Addr (*)(void))ptr)();
661 return ((void *)target);
665 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
669 const Obj_Entry *defobj;
672 RtldLockState lockstate;
674 rlock_acquire(rtld_bind_lock, &lockstate);
675 if (sigsetjmp(lockstate.env, 0) != 0)
676 lock_upgrade(rtld_bind_lock, &lockstate);
678 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
680 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
682 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
683 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
687 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
688 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
690 target = (Elf_Addr)(defobj->relocbase + def->st_value);
692 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
693 defobj->strtab + def->st_name, basename(obj->path),
694 (void *)target, basename(defobj->path));
697 * Write the new contents for the jmpslot. Note that depending on
698 * architecture, the value which we need to return back to the
699 * lazy binding trampoline may or may not be the target
700 * address. The value returned from reloc_jmpslot() is the value
701 * that the trampoline needs.
703 target = reloc_jmpslot(where, target, defobj, obj, rel);
704 lock_release(rtld_bind_lock, &lockstate);
709 * Error reporting function. Use it like printf. If formats the message
710 * into a buffer, and sets things up so that the next call to dlerror()
711 * will return the message.
714 _rtld_error(const char *fmt, ...)
716 static char buf[512];
720 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
726 * Return a dynamically-allocated copy of the current error message, if any.
731 return error_message == NULL ? NULL : xstrdup(error_message);
735 * Restore the current error message from a copy which was previously saved
736 * by errmsg_save(). The copy is freed.
739 errmsg_restore(char *saved_msg)
741 if (saved_msg == NULL)
742 error_message = NULL;
744 _rtld_error("%s", saved_msg);
750 basename(const char *name)
752 const char *p = strrchr(name, '/');
753 return p != NULL ? p + 1 : name;
756 static struct utsname uts;
759 origin_subst_one(char *real, const char *kw, const char *subst,
762 char *p, *p1, *res, *resp;
763 int subst_len, kw_len, subst_count, old_len, new_len;
768 * First, count the number of the keyword occurences, to
769 * preallocate the final string.
771 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
778 * If the keyword is not found, just return.
780 if (subst_count == 0)
781 return (may_free ? real : xstrdup(real));
784 * There is indeed something to substitute. Calculate the
785 * length of the resulting string, and allocate it.
787 subst_len = strlen(subst);
788 old_len = strlen(real);
789 new_len = old_len + (subst_len - kw_len) * subst_count;
790 res = xmalloc(new_len + 1);
793 * Now, execute the substitution loop.
795 for (p = real, resp = res, *resp = '\0';;) {
798 /* Copy the prefix before keyword. */
799 memcpy(resp, p, p1 - p);
801 /* Keyword replacement. */
802 memcpy(resp, subst, subst_len);
810 /* Copy to the end of string and finish. */
818 origin_subst(char *real, const char *origin_path)
820 char *res1, *res2, *res3, *res4;
822 if (uts.sysname[0] == '\0') {
823 if (uname(&uts) != 0) {
824 _rtld_error("utsname failed: %d", errno);
828 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false);
829 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true);
830 res3 = origin_subst_one(res2, "$OSREL", uts.release, true);
831 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true);
838 const char *msg = dlerror();
842 rtld_fdputstr(STDERR_FILENO, msg);
843 rtld_fdputchar(STDERR_FILENO, '\n');
848 * Process a shared object's DYNAMIC section, and save the important
849 * information in its Obj_Entry structure.
852 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
853 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
856 Needed_Entry **needed_tail = &obj->needed;
857 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
858 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
859 const Elf_Hashelt *hashtab;
860 const Elf32_Word *hashval;
861 Elf32_Word bkt, nmaskwords;
864 int plttype = DT_REL;
870 obj->bind_now = false;
871 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
872 switch (dynp->d_tag) {
875 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
879 obj->relsize = dynp->d_un.d_val;
883 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
887 obj->pltrel = (const Elf_Rel *)
888 (obj->relocbase + dynp->d_un.d_ptr);
892 obj->pltrelsize = dynp->d_un.d_val;
896 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
900 obj->relasize = dynp->d_un.d_val;
904 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
908 plttype = dynp->d_un.d_val;
909 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
913 obj->symtab = (const Elf_Sym *)
914 (obj->relocbase + dynp->d_un.d_ptr);
918 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
922 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
926 obj->strsize = dynp->d_un.d_val;
930 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
935 obj->verneednum = dynp->d_un.d_val;
939 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
944 obj->verdefnum = dynp->d_un.d_val;
948 obj->versyms = (const Elf_Versym *)(obj->relocbase +
954 hashtab = (const Elf_Hashelt *)(obj->relocbase +
956 obj->nbuckets = hashtab[0];
957 obj->nchains = hashtab[1];
958 obj->buckets = hashtab + 2;
959 obj->chains = obj->buckets + obj->nbuckets;
960 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
961 obj->buckets != NULL;
967 hashtab = (const Elf_Hashelt *)(obj->relocbase +
969 obj->nbuckets_gnu = hashtab[0];
970 obj->symndx_gnu = hashtab[1];
971 nmaskwords = hashtab[2];
972 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
973 /* Number of bitmask words is required to be power of 2 */
974 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0);
975 obj->maskwords_bm_gnu = nmaskwords - 1;
976 obj->shift2_gnu = hashtab[3];
977 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
978 obj->buckets_gnu = hashtab + 4 + bloom_size32;
979 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
981 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 &&
982 obj->buckets_gnu != NULL;
988 Needed_Entry *nep = NEW(Needed_Entry);
989 nep->name = dynp->d_un.d_val;
994 needed_tail = &nep->next;
1000 Needed_Entry *nep = NEW(Needed_Entry);
1001 nep->name = dynp->d_un.d_val;
1005 *needed_filtees_tail = nep;
1006 needed_filtees_tail = &nep->next;
1012 Needed_Entry *nep = NEW(Needed_Entry);
1013 nep->name = dynp->d_un.d_val;
1017 *needed_aux_filtees_tail = nep;
1018 needed_aux_filtees_tail = &nep->next;
1023 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1027 obj->textrel = true;
1031 obj->symbolic = true;
1036 * We have to wait until later to process this, because we
1037 * might not have gotten the address of the string table yet.
1047 *dyn_runpath = dynp;
1051 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1054 case DT_PREINIT_ARRAY:
1055 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1058 case DT_PREINIT_ARRAYSZ:
1059 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1063 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1066 case DT_INIT_ARRAYSZ:
1067 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1071 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1075 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1078 case DT_FINI_ARRAYSZ:
1079 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1083 * Don't process DT_DEBUG on MIPS as the dynamic section
1084 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1089 /* XXX - not implemented yet */
1091 dbg("Filling in DT_DEBUG entry");
1092 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1097 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1098 obj->z_origin = true;
1099 if (dynp->d_un.d_val & DF_SYMBOLIC)
1100 obj->symbolic = true;
1101 if (dynp->d_un.d_val & DF_TEXTREL)
1102 obj->textrel = true;
1103 if (dynp->d_un.d_val & DF_BIND_NOW)
1104 obj->bind_now = true;
1105 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1109 case DT_MIPS_LOCAL_GOTNO:
1110 obj->local_gotno = dynp->d_un.d_val;
1113 case DT_MIPS_SYMTABNO:
1114 obj->symtabno = dynp->d_un.d_val;
1117 case DT_MIPS_GOTSYM:
1118 obj->gotsym = dynp->d_un.d_val;
1121 case DT_MIPS_RLD_MAP:
1124 dbg("Filling in DT_DEBUG entry");
1125 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1131 if (dynp->d_un.d_val & DF_1_NOOPEN)
1132 obj->z_noopen = true;
1133 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1134 obj->z_origin = true;
1135 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1137 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1138 obj->bind_now = true;
1139 if (dynp->d_un.d_val & DF_1_NODELETE)
1140 obj->z_nodelete = true;
1141 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1142 obj->z_loadfltr = true;
1143 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1144 obj->z_interpose = true;
1145 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1146 obj->z_nodeflib = true;
1151 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1158 obj->traced = false;
1160 if (plttype == DT_RELA) {
1161 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1163 obj->pltrelasize = obj->pltrelsize;
1164 obj->pltrelsize = 0;
1167 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1168 if (obj->valid_hash_sysv)
1169 obj->dynsymcount = obj->nchains;
1170 else if (obj->valid_hash_gnu) {
1171 obj->dynsymcount = 0;
1172 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1173 if (obj->buckets_gnu[bkt] == 0)
1175 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1178 while ((*hashval++ & 1u) == 0);
1180 obj->dynsymcount += obj->symndx_gnu;
1185 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1186 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1189 if (obj->z_origin && obj->origin_path == NULL) {
1190 obj->origin_path = xmalloc(PATH_MAX);
1191 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1195 if (dyn_runpath != NULL) {
1196 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1198 obj->runpath = origin_subst(obj->runpath, obj->origin_path);
1200 else if (dyn_rpath != NULL) {
1201 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1203 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1206 if (dyn_soname != NULL)
1207 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1211 digest_dynamic(Obj_Entry *obj, int early)
1213 const Elf_Dyn *dyn_rpath;
1214 const Elf_Dyn *dyn_soname;
1215 const Elf_Dyn *dyn_runpath;
1217 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1218 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1222 * Process a shared object's program header. This is used only for the
1223 * main program, when the kernel has already loaded the main program
1224 * into memory before calling the dynamic linker. It creates and
1225 * returns an Obj_Entry structure.
1228 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1231 const Elf_Phdr *phlimit = phdr + phnum;
1233 Elf_Addr note_start, note_end;
1237 for (ph = phdr; ph < phlimit; ph++) {
1238 if (ph->p_type != PT_PHDR)
1242 obj->phsize = ph->p_memsz;
1243 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1247 obj->stack_flags = PF_X | PF_R | PF_W;
1249 for (ph = phdr; ph < phlimit; ph++) {
1250 switch (ph->p_type) {
1253 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1257 if (nsegs == 0) { /* First load segment */
1258 obj->vaddrbase = trunc_page(ph->p_vaddr);
1259 obj->mapbase = obj->vaddrbase + obj->relocbase;
1260 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1262 } else { /* Last load segment */
1263 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1270 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1275 obj->tlssize = ph->p_memsz;
1276 obj->tlsalign = ph->p_align;
1277 obj->tlsinitsize = ph->p_filesz;
1278 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1282 obj->stack_flags = ph->p_flags;
1286 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1287 obj->relro_size = round_page(ph->p_memsz);
1291 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1292 note_end = note_start + ph->p_filesz;
1293 digest_notes(obj, note_start, note_end);
1298 _rtld_error("%s: too few PT_LOAD segments", path);
1307 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1309 const Elf_Note *note;
1310 const char *note_name;
1313 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1314 note = (const Elf_Note *)((const char *)(note + 1) +
1315 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1316 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1317 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1318 note->n_descsz != sizeof(int32_t))
1320 if (note->n_type != ABI_NOTETYPE &&
1321 note->n_type != CRT_NOINIT_NOTETYPE)
1323 note_name = (const char *)(note + 1);
1324 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1325 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1327 switch (note->n_type) {
1329 /* FreeBSD osrel note */
1330 p = (uintptr_t)(note + 1);
1331 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1332 obj->osrel = *(const int32_t *)(p);
1333 dbg("note osrel %d", obj->osrel);
1335 case CRT_NOINIT_NOTETYPE:
1336 /* FreeBSD 'crt does not call init' note */
1337 obj->crt_no_init = true;
1338 dbg("note crt_no_init");
1345 dlcheck(void *handle)
1349 for (obj = obj_list; obj != NULL; obj = obj->next)
1350 if (obj == (Obj_Entry *) handle)
1353 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1354 _rtld_error("Invalid shared object handle %p", handle);
1361 * If the given object is already in the donelist, return true. Otherwise
1362 * add the object to the list and return false.
1365 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1369 for (i = 0; i < dlp->num_used; i++)
1370 if (dlp->objs[i] == obj)
1373 * Our donelist allocation should always be sufficient. But if
1374 * our threads locking isn't working properly, more shared objects
1375 * could have been loaded since we allocated the list. That should
1376 * never happen, but we'll handle it properly just in case it does.
1378 if (dlp->num_used < dlp->num_alloc)
1379 dlp->objs[dlp->num_used++] = obj;
1384 * Hash function for symbol table lookup. Don't even think about changing
1385 * this. It is specified by the System V ABI.
1388 elf_hash(const char *name)
1390 const unsigned char *p = (const unsigned char *) name;
1391 unsigned long h = 0;
1394 while (*p != '\0') {
1395 h = (h << 4) + *p++;
1396 if ((g = h & 0xf0000000) != 0)
1404 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1405 * unsigned in case it's implemented with a wider type.
1408 gnu_hash(const char *s)
1414 for (c = *s; c != '\0'; c = *++s)
1416 return (h & 0xffffffff);
1420 * Find the library with the given name, and return its full pathname.
1421 * The returned string is dynamically allocated. Generates an error
1422 * message and returns NULL if the library cannot be found.
1424 * If the second argument is non-NULL, then it refers to an already-
1425 * loaded shared object, whose library search path will be searched.
1427 * The search order is:
1428 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1429 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1431 * DT_RUNPATH in the referencing file
1432 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1434 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1436 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1439 find_library(const char *xname, const Obj_Entry *refobj)
1443 bool nodeflib, objgiven;
1445 objgiven = refobj != NULL;
1446 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1447 if (xname[0] != '/' && !trust) {
1448 _rtld_error("Absolute pathname required for shared object \"%s\"",
1452 if (objgiven && refobj->z_origin) {
1453 return (origin_subst(__DECONST(char *, xname),
1454 refobj->origin_path));
1456 return (xstrdup(xname));
1460 if (libmap_disable || !objgiven ||
1461 (name = lm_find(refobj->path, xname)) == NULL)
1462 name = (char *)xname;
1464 dbg(" Searching for \"%s\"", name);
1467 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1468 * back to pre-conforming behaviour if user requested so with
1469 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1472 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1473 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1475 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1476 (pathname = search_library_path(name, gethints(false))) != NULL ||
1477 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1480 nodeflib = objgiven ? refobj->z_nodeflib : false;
1482 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1483 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1484 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1485 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1487 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1488 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1489 (objgiven && !nodeflib &&
1490 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1494 if (objgiven && refobj->path != NULL) {
1495 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1496 name, basename(refobj->path));
1498 _rtld_error("Shared object \"%s\" not found", name);
1504 * Given a symbol number in a referencing object, find the corresponding
1505 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1506 * no definition was found. Returns a pointer to the Obj_Entry of the
1507 * defining object via the reference parameter DEFOBJ_OUT.
1510 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1511 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1512 RtldLockState *lockstate)
1516 const Obj_Entry *defobj;
1522 * If we have already found this symbol, get the information from
1525 if (symnum >= refobj->dynsymcount)
1526 return NULL; /* Bad object */
1527 if (cache != NULL && cache[symnum].sym != NULL) {
1528 *defobj_out = cache[symnum].obj;
1529 return cache[symnum].sym;
1532 ref = refobj->symtab + symnum;
1533 name = refobj->strtab + ref->st_name;
1538 * We don't have to do a full scale lookup if the symbol is local.
1539 * We know it will bind to the instance in this load module; to
1540 * which we already have a pointer (ie ref). By not doing a lookup,
1541 * we not only improve performance, but it also avoids unresolvable
1542 * symbols when local symbols are not in the hash table. This has
1543 * been seen with the ia64 toolchain.
1545 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1546 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1547 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1550 symlook_init(&req, name);
1552 req.ventry = fetch_ventry(refobj, symnum);
1553 req.lockstate = lockstate;
1554 res = symlook_default(&req, refobj);
1557 defobj = req.defobj_out;
1565 * If we found no definition and the reference is weak, treat the
1566 * symbol as having the value zero.
1568 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1574 *defobj_out = defobj;
1575 /* Record the information in the cache to avoid subsequent lookups. */
1576 if (cache != NULL) {
1577 cache[symnum].sym = def;
1578 cache[symnum].obj = defobj;
1581 if (refobj != &obj_rtld)
1582 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1588 * Return the search path from the ldconfig hints file, reading it if
1589 * necessary. If nostdlib is true, then the default search paths are
1590 * not added to result.
1592 * Returns NULL if there are problems with the hints file,
1593 * or if the search path there is empty.
1596 gethints(bool nostdlib)
1598 static char *hints, *filtered_path;
1599 struct elfhints_hdr hdr;
1600 struct fill_search_info_args sargs, hargs;
1601 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1602 struct dl_serpath *SLPpath, *hintpath;
1604 unsigned int SLPndx, hintndx, fndx, fcount;
1609 /* First call, read the hints file */
1610 if (hints == NULL) {
1611 /* Keep from trying again in case the hints file is bad. */
1614 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1)
1616 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1617 hdr.magic != ELFHINTS_MAGIC ||
1622 p = xmalloc(hdr.dirlistlen + 1);
1623 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1624 read(fd, p, hdr.dirlistlen + 1) !=
1625 (ssize_t)hdr.dirlistlen + 1) {
1635 * If caller agreed to receive list which includes the default
1636 * paths, we are done. Otherwise, if we still did not
1637 * calculated filtered result, do it now.
1640 return (hints[0] != '\0' ? hints : NULL);
1641 if (filtered_path != NULL)
1645 * Obtain the list of all configured search paths, and the
1646 * list of the default paths.
1648 * First estimate the size of the results.
1650 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1652 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1655 sargs.request = RTLD_DI_SERINFOSIZE;
1656 sargs.serinfo = &smeta;
1657 hargs.request = RTLD_DI_SERINFOSIZE;
1658 hargs.serinfo = &hmeta;
1660 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1661 path_enumerate(p, fill_search_info, &hargs);
1663 SLPinfo = xmalloc(smeta.dls_size);
1664 hintinfo = xmalloc(hmeta.dls_size);
1667 * Next fetch both sets of paths.
1669 sargs.request = RTLD_DI_SERINFO;
1670 sargs.serinfo = SLPinfo;
1671 sargs.serpath = &SLPinfo->dls_serpath[0];
1672 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1674 hargs.request = RTLD_DI_SERINFO;
1675 hargs.serinfo = hintinfo;
1676 hargs.serpath = &hintinfo->dls_serpath[0];
1677 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1679 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1680 path_enumerate(p, fill_search_info, &hargs);
1683 * Now calculate the difference between two sets, by excluding
1684 * standard paths from the full set.
1688 filtered_path = xmalloc(hdr.dirlistlen + 1);
1689 hintpath = &hintinfo->dls_serpath[0];
1690 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1692 SLPpath = &SLPinfo->dls_serpath[0];
1694 * Check each standard path against current.
1696 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1697 /* matched, skip the path */
1698 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1706 * Not matched against any standard path, add the path
1707 * to result. Separate consequtive paths with ':'.
1710 filtered_path[fndx] = ':';
1714 flen = strlen(hintpath->dls_name);
1715 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1718 filtered_path[fndx] = '\0';
1724 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1728 init_dag(Obj_Entry *root)
1730 const Needed_Entry *needed;
1731 const Objlist_Entry *elm;
1734 if (root->dag_inited)
1736 donelist_init(&donelist);
1738 /* Root object belongs to own DAG. */
1739 objlist_push_tail(&root->dldags, root);
1740 objlist_push_tail(&root->dagmembers, root);
1741 donelist_check(&donelist, root);
1744 * Add dependencies of root object to DAG in breadth order
1745 * by exploiting the fact that each new object get added
1746 * to the tail of the dagmembers list.
1748 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1749 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1750 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1752 objlist_push_tail(&needed->obj->dldags, root);
1753 objlist_push_tail(&root->dagmembers, needed->obj);
1756 root->dag_inited = true;
1760 process_nodelete(Obj_Entry *root)
1762 const Objlist_Entry *elm;
1765 * Walk over object DAG and process every dependent object that
1766 * is marked as DF_1_NODELETE. They need to grow their own DAG,
1767 * which then should have its reference upped separately.
1769 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1770 if (elm->obj != NULL && elm->obj->z_nodelete &&
1771 !elm->obj->ref_nodel) {
1772 dbg("obj %s nodelete", elm->obj->path);
1775 elm->obj->ref_nodel = true;
1780 * Initialize the dynamic linker. The argument is the address at which
1781 * the dynamic linker has been mapped into memory. The primary task of
1782 * this function is to relocate the dynamic linker.
1785 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1787 Obj_Entry objtmp; /* Temporary rtld object */
1788 const Elf_Dyn *dyn_rpath;
1789 const Elf_Dyn *dyn_soname;
1790 const Elf_Dyn *dyn_runpath;
1793 * Conjure up an Obj_Entry structure for the dynamic linker.
1795 * The "path" member can't be initialized yet because string constants
1796 * cannot yet be accessed. Below we will set it correctly.
1798 memset(&objtmp, 0, sizeof(objtmp));
1801 objtmp.mapbase = mapbase;
1803 objtmp.relocbase = mapbase;
1805 if (RTLD_IS_DYNAMIC()) {
1806 objtmp.dynamic = rtld_dynamic(&objtmp);
1807 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1808 assert(objtmp.needed == NULL);
1809 #if !defined(__mips__)
1810 /* MIPS has a bogus DT_TEXTREL. */
1811 assert(!objtmp.textrel);
1815 * Temporarily put the dynamic linker entry into the object list, so
1816 * that symbols can be found.
1819 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1822 /* Initialize the object list. */
1823 obj_tail = &obj_list;
1825 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1826 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1828 if (aux_info[AT_PAGESZ] != NULL)
1829 pagesize = aux_info[AT_PAGESZ]->a_un.a_val;
1830 if (aux_info[AT_OSRELDATE] != NULL)
1831 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1833 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1835 /* Replace the path with a dynamically allocated copy. */
1836 obj_rtld.path = xstrdup(PATH_RTLD);
1838 r_debug.r_brk = r_debug_state;
1839 r_debug.r_state = RT_CONSISTENT;
1843 * Add the init functions from a needed object list (and its recursive
1844 * needed objects) to "list". This is not used directly; it is a helper
1845 * function for initlist_add_objects(). The write lock must be held
1846 * when this function is called.
1849 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1851 /* Recursively process the successor needed objects. */
1852 if (needed->next != NULL)
1853 initlist_add_neededs(needed->next, list);
1855 /* Process the current needed object. */
1856 if (needed->obj != NULL)
1857 initlist_add_objects(needed->obj, &needed->obj->next, list);
1861 * Scan all of the DAGs rooted in the range of objects from "obj" to
1862 * "tail" and add their init functions to "list". This recurses over
1863 * the DAGs and ensure the proper init ordering such that each object's
1864 * needed libraries are initialized before the object itself. At the
1865 * same time, this function adds the objects to the global finalization
1866 * list "list_fini" in the opposite order. The write lock must be
1867 * held when this function is called.
1870 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1873 if (obj->init_scanned || obj->init_done)
1875 obj->init_scanned = true;
1877 /* Recursively process the successor objects. */
1878 if (&obj->next != tail)
1879 initlist_add_objects(obj->next, tail, list);
1881 /* Recursively process the needed objects. */
1882 if (obj->needed != NULL)
1883 initlist_add_neededs(obj->needed, list);
1884 if (obj->needed_filtees != NULL)
1885 initlist_add_neededs(obj->needed_filtees, list);
1886 if (obj->needed_aux_filtees != NULL)
1887 initlist_add_neededs(obj->needed_aux_filtees, list);
1889 /* Add the object to the init list. */
1890 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1891 obj->init_array != (Elf_Addr)NULL)
1892 objlist_push_tail(list, obj);
1894 /* Add the object to the global fini list in the reverse order. */
1895 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1896 && !obj->on_fini_list) {
1897 objlist_push_head(&list_fini, obj);
1898 obj->on_fini_list = true;
1903 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1907 free_needed_filtees(Needed_Entry *n)
1909 Needed_Entry *needed, *needed1;
1911 for (needed = n; needed != NULL; needed = needed->next) {
1912 if (needed->obj != NULL) {
1913 dlclose(needed->obj);
1917 for (needed = n; needed != NULL; needed = needed1) {
1918 needed1 = needed->next;
1924 unload_filtees(Obj_Entry *obj)
1927 free_needed_filtees(obj->needed_filtees);
1928 obj->needed_filtees = NULL;
1929 free_needed_filtees(obj->needed_aux_filtees);
1930 obj->needed_aux_filtees = NULL;
1931 obj->filtees_loaded = false;
1935 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
1936 RtldLockState *lockstate)
1939 for (; needed != NULL; needed = needed->next) {
1940 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
1941 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
1942 RTLD_LOCAL, lockstate);
1947 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
1950 lock_restart_for_upgrade(lockstate);
1951 if (!obj->filtees_loaded) {
1952 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
1953 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
1954 obj->filtees_loaded = true;
1959 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
1963 for (; needed != NULL; needed = needed->next) {
1964 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
1965 flags & ~RTLD_LO_NOLOAD);
1966 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
1973 * Given a shared object, traverse its list of needed objects, and load
1974 * each of them. Returns 0 on success. Generates an error message and
1975 * returns -1 on failure.
1978 load_needed_objects(Obj_Entry *first, int flags)
1982 for (obj = first; obj != NULL; obj = obj->next) {
1983 if (process_needed(obj, obj->needed, flags) == -1)
1990 load_preload_objects(void)
1992 char *p = ld_preload;
1994 static const char delim[] = " \t:;";
1999 p += strspn(p, delim);
2000 while (*p != '\0') {
2001 size_t len = strcspn(p, delim);
2006 obj = load_object(p, -1, NULL, 0);
2008 return -1; /* XXX - cleanup */
2009 obj->z_interpose = true;
2012 p += strspn(p, delim);
2014 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2019 printable_path(const char *path)
2022 return (path == NULL ? "<unknown>" : path);
2026 * Load a shared object into memory, if it is not already loaded. The
2027 * object may be specified by name or by user-supplied file descriptor
2028 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2031 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2035 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2043 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2044 if (object_match_name(obj, name))
2048 path = find_library(name, refobj);
2055 * If we didn't find a match by pathname, or the name is not
2056 * supplied, open the file and check again by device and inode.
2057 * This avoids false mismatches caused by multiple links or ".."
2060 * To avoid a race, we open the file and use fstat() rather than
2065 if ((fd = open(path, O_RDONLY)) == -1) {
2066 _rtld_error("Cannot open \"%s\"", path);
2073 _rtld_error("Cannot dup fd");
2078 if (fstat(fd, &sb) == -1) {
2079 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2084 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2085 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2087 if (obj != NULL && name != NULL) {
2088 object_add_name(obj, name);
2093 if (flags & RTLD_LO_NOLOAD) {
2099 /* First use of this object, so we must map it in */
2100 obj = do_load_object(fd, name, path, &sb, flags);
2109 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2116 * but first, make sure that environment variables haven't been
2117 * used to circumvent the noexec flag on a filesystem.
2119 if (dangerous_ld_env) {
2120 if (fstatfs(fd, &fs) != 0) {
2121 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2124 if (fs.f_flags & MNT_NOEXEC) {
2125 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2129 dbg("loading \"%s\"", printable_path(path));
2130 obj = map_object(fd, printable_path(path), sbp);
2135 * If DT_SONAME is present in the object, digest_dynamic2 already
2136 * added it to the object names.
2139 object_add_name(obj, name);
2141 digest_dynamic(obj, 0);
2142 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2143 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2144 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2146 dbg("refusing to load non-loadable \"%s\"", obj->path);
2147 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2148 munmap(obj->mapbase, obj->mapsize);
2154 obj_tail = &obj->next;
2157 linkmap_add(obj); /* for GDB & dlinfo() */
2158 max_stack_flags |= obj->stack_flags;
2160 dbg(" %p .. %p: %s", obj->mapbase,
2161 obj->mapbase + obj->mapsize - 1, obj->path);
2163 dbg(" WARNING: %s has impure text", obj->path);
2164 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2171 obj_from_addr(const void *addr)
2175 for (obj = obj_list; obj != NULL; obj = obj->next) {
2176 if (addr < (void *) obj->mapbase)
2178 if (addr < (void *) (obj->mapbase + obj->mapsize))
2187 Elf_Addr *preinit_addr;
2190 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2191 if (preinit_addr == NULL)
2194 for (index = 0; index < obj_main->preinit_array_num; index++) {
2195 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2196 dbg("calling preinit function for %s at %p", obj_main->path,
2197 (void *)preinit_addr[index]);
2198 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2199 0, 0, obj_main->path);
2200 call_init_pointer(obj_main, preinit_addr[index]);
2206 * Call the finalization functions for each of the objects in "list"
2207 * belonging to the DAG of "root" and referenced once. If NULL "root"
2208 * is specified, every finalization function will be called regardless
2209 * of the reference count and the list elements won't be freed. All of
2210 * the objects are expected to have non-NULL fini functions.
2213 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2217 Elf_Addr *fini_addr;
2220 assert(root == NULL || root->refcount == 1);
2223 * Preserve the current error message since a fini function might
2224 * call into the dynamic linker and overwrite it.
2226 saved_msg = errmsg_save();
2228 STAILQ_FOREACH(elm, list, link) {
2229 if (root != NULL && (elm->obj->refcount != 1 ||
2230 objlist_find(&root->dagmembers, elm->obj) == NULL))
2232 /* Remove object from fini list to prevent recursive invocation. */
2233 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2235 * XXX: If a dlopen() call references an object while the
2236 * fini function is in progress, we might end up trying to
2237 * unload the referenced object in dlclose() or the object
2238 * won't be unloaded although its fini function has been
2241 lock_release(rtld_bind_lock, lockstate);
2244 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2245 * When this happens, DT_FINI_ARRAY is processed first.
2247 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2248 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2249 for (index = elm->obj->fini_array_num - 1; index >= 0;
2251 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2252 dbg("calling fini function for %s at %p",
2253 elm->obj->path, (void *)fini_addr[index]);
2254 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2255 (void *)fini_addr[index], 0, 0, elm->obj->path);
2256 call_initfini_pointer(elm->obj, fini_addr[index]);
2260 if (elm->obj->fini != (Elf_Addr)NULL) {
2261 dbg("calling fini function for %s at %p", elm->obj->path,
2262 (void *)elm->obj->fini);
2263 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2264 0, 0, elm->obj->path);
2265 call_initfini_pointer(elm->obj, elm->obj->fini);
2267 wlock_acquire(rtld_bind_lock, lockstate);
2268 /* No need to free anything if process is going down. */
2272 * We must restart the list traversal after every fini call
2273 * because a dlclose() call from the fini function or from
2274 * another thread might have modified the reference counts.
2278 } while (elm != NULL);
2279 errmsg_restore(saved_msg);
2283 * Call the initialization functions for each of the objects in
2284 * "list". All of the objects are expected to have non-NULL init
2288 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2293 Elf_Addr *init_addr;
2297 * Clean init_scanned flag so that objects can be rechecked and
2298 * possibly initialized earlier if any of vectors called below
2299 * cause the change by using dlopen.
2301 for (obj = obj_list; obj != NULL; obj = obj->next)
2302 obj->init_scanned = false;
2305 * Preserve the current error message since an init function might
2306 * call into the dynamic linker and overwrite it.
2308 saved_msg = errmsg_save();
2309 STAILQ_FOREACH(elm, list, link) {
2310 if (elm->obj->init_done) /* Initialized early. */
2313 * Race: other thread might try to use this object before current
2314 * one completes the initilization. Not much can be done here
2315 * without better locking.
2317 elm->obj->init_done = true;
2318 lock_release(rtld_bind_lock, lockstate);
2321 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2322 * When this happens, DT_INIT is processed first.
2324 if (elm->obj->init != (Elf_Addr)NULL) {
2325 dbg("calling init function for %s at %p", elm->obj->path,
2326 (void *)elm->obj->init);
2327 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2328 0, 0, elm->obj->path);
2329 call_initfini_pointer(elm->obj, elm->obj->init);
2331 init_addr = (Elf_Addr *)elm->obj->init_array;
2332 if (init_addr != NULL) {
2333 for (index = 0; index < elm->obj->init_array_num; index++) {
2334 if (init_addr[index] != 0 && init_addr[index] != 1) {
2335 dbg("calling init function for %s at %p", elm->obj->path,
2336 (void *)init_addr[index]);
2337 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2338 (void *)init_addr[index], 0, 0, elm->obj->path);
2339 call_init_pointer(elm->obj, init_addr[index]);
2343 wlock_acquire(rtld_bind_lock, lockstate);
2345 errmsg_restore(saved_msg);
2349 objlist_clear(Objlist *list)
2353 while (!STAILQ_EMPTY(list)) {
2354 elm = STAILQ_FIRST(list);
2355 STAILQ_REMOVE_HEAD(list, link);
2360 static Objlist_Entry *
2361 objlist_find(Objlist *list, const Obj_Entry *obj)
2365 STAILQ_FOREACH(elm, list, link)
2366 if (elm->obj == obj)
2372 objlist_init(Objlist *list)
2378 objlist_push_head(Objlist *list, Obj_Entry *obj)
2382 elm = NEW(Objlist_Entry);
2384 STAILQ_INSERT_HEAD(list, elm, link);
2388 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2392 elm = NEW(Objlist_Entry);
2394 STAILQ_INSERT_TAIL(list, elm, link);
2398 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2400 Objlist_Entry *elm, *listelm;
2402 STAILQ_FOREACH(listelm, list, link) {
2403 if (listelm->obj == listobj)
2406 elm = NEW(Objlist_Entry);
2408 if (listelm != NULL)
2409 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2411 STAILQ_INSERT_TAIL(list, elm, link);
2415 objlist_remove(Objlist *list, Obj_Entry *obj)
2419 if ((elm = objlist_find(list, obj)) != NULL) {
2420 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2426 * Relocate dag rooted in the specified object.
2427 * Returns 0 on success, or -1 on failure.
2431 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2432 int flags, RtldLockState *lockstate)
2438 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2439 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2448 * Relocate single object.
2449 * Returns 0 on success, or -1 on failure.
2452 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2453 int flags, RtldLockState *lockstate)
2458 obj->relocated = true;
2460 dbg("relocating \"%s\"", obj->path);
2462 if (obj->symtab == NULL || obj->strtab == NULL ||
2463 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2464 _rtld_error("%s: Shared object has no run-time symbol table",
2470 /* There are relocations to the write-protected text segment. */
2471 if (mprotect(obj->mapbase, obj->textsize,
2472 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2473 _rtld_error("%s: Cannot write-enable text segment: %s",
2474 obj->path, rtld_strerror(errno));
2479 /* Process the non-PLT relocations. */
2480 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2483 if (obj->textrel) { /* Re-protected the text segment. */
2484 if (mprotect(obj->mapbase, obj->textsize,
2485 PROT_READ|PROT_EXEC) == -1) {
2486 _rtld_error("%s: Cannot write-protect text segment: %s",
2487 obj->path, rtld_strerror(errno));
2493 /* Set the special PLT or GOT entries. */
2496 /* Process the PLT relocations. */
2497 if (reloc_plt(obj) == -1)
2499 /* Relocate the jump slots if we are doing immediate binding. */
2500 if (obj->bind_now || bind_now)
2501 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2504 if (obj->relro_size > 0) {
2505 if (mprotect(obj->relro_page, obj->relro_size,
2507 _rtld_error("%s: Cannot enforce relro protection: %s",
2508 obj->path, rtld_strerror(errno));
2514 * Set up the magic number and version in the Obj_Entry. These
2515 * were checked in the crt1.o from the original ElfKit, so we
2516 * set them for backward compatibility.
2518 obj->magic = RTLD_MAGIC;
2519 obj->version = RTLD_VERSION;
2525 * Relocate newly-loaded shared objects. The argument is a pointer to
2526 * the Obj_Entry for the first such object. All objects from the first
2527 * to the end of the list of objects are relocated. Returns 0 on success,
2531 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2532 int flags, RtldLockState *lockstate)
2537 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2538 error = relocate_object(obj, bind_now, rtldobj, flags,
2547 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2548 * referencing STT_GNU_IFUNC symbols is postponed till the other
2549 * relocations are done. The indirect functions specified as
2550 * ifunc are allowed to call other symbols, so we need to have
2551 * objects relocated before asking for resolution from indirects.
2553 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2554 * instead of the usual lazy handling of PLT slots. It is
2555 * consistent with how GNU does it.
2558 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2559 RtldLockState *lockstate)
2561 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2563 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2564 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2570 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2571 RtldLockState *lockstate)
2575 for (obj = first; obj != NULL; obj = obj->next) {
2576 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2583 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2584 RtldLockState *lockstate)
2588 STAILQ_FOREACH(elm, list, link) {
2589 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2597 * Cleanup procedure. It will be called (by the atexit mechanism) just
2598 * before the process exits.
2603 RtldLockState lockstate;
2605 wlock_acquire(rtld_bind_lock, &lockstate);
2607 objlist_call_fini(&list_fini, NULL, &lockstate);
2608 /* No need to remove the items from the list, since we are exiting. */
2609 if (!libmap_disable)
2611 lock_release(rtld_bind_lock, &lockstate);
2615 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2623 path += strspn(path, ":;");
2624 while (*path != '\0') {
2628 len = strcspn(path, ":;");
2630 trans = lm_findn(NULL, path, len);
2632 res = callback(trans, strlen(trans), arg);
2635 res = callback(path, len, arg);
2641 path += strspn(path, ":;");
2647 struct try_library_args {
2655 try_library_path(const char *dir, size_t dirlen, void *param)
2657 struct try_library_args *arg;
2660 if (*dir == '/' || trust) {
2663 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2666 pathname = arg->buffer;
2667 strncpy(pathname, dir, dirlen);
2668 pathname[dirlen] = '/';
2669 strcpy(pathname + dirlen + 1, arg->name);
2671 dbg(" Trying \"%s\"", pathname);
2672 if (access(pathname, F_OK) == 0) { /* We found it */
2673 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2674 strcpy(pathname, arg->buffer);
2682 search_library_path(const char *name, const char *path)
2685 struct try_library_args arg;
2691 arg.namelen = strlen(name);
2692 arg.buffer = xmalloc(PATH_MAX);
2693 arg.buflen = PATH_MAX;
2695 p = path_enumerate(path, try_library_path, &arg);
2703 dlclose(void *handle)
2706 RtldLockState lockstate;
2708 wlock_acquire(rtld_bind_lock, &lockstate);
2709 root = dlcheck(handle);
2711 lock_release(rtld_bind_lock, &lockstate);
2714 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2717 /* Unreference the object and its dependencies. */
2718 root->dl_refcount--;
2720 if (root->refcount == 1) {
2722 * The object will be no longer referenced, so we must unload it.
2723 * First, call the fini functions.
2725 objlist_call_fini(&list_fini, root, &lockstate);
2729 /* Finish cleaning up the newly-unreferenced objects. */
2730 GDB_STATE(RT_DELETE,&root->linkmap);
2731 unload_object(root);
2732 GDB_STATE(RT_CONSISTENT,NULL);
2736 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2737 lock_release(rtld_bind_lock, &lockstate);
2744 char *msg = error_message;
2745 error_message = NULL;
2750 * This function is deprecated and has no effect.
2753 dllockinit(void *context,
2754 void *(*lock_create)(void *context),
2755 void (*rlock_acquire)(void *lock),
2756 void (*wlock_acquire)(void *lock),
2757 void (*lock_release)(void *lock),
2758 void (*lock_destroy)(void *lock),
2759 void (*context_destroy)(void *context))
2761 static void *cur_context;
2762 static void (*cur_context_destroy)(void *);
2764 /* Just destroy the context from the previous call, if necessary. */
2765 if (cur_context_destroy != NULL)
2766 cur_context_destroy(cur_context);
2767 cur_context = context;
2768 cur_context_destroy = context_destroy;
2772 dlopen(const char *name, int mode)
2775 return (rtld_dlopen(name, -1, mode));
2779 fdlopen(int fd, int mode)
2782 return (rtld_dlopen(NULL, fd, mode));
2786 rtld_dlopen(const char *name, int fd, int mode)
2788 RtldLockState lockstate;
2791 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2792 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2793 if (ld_tracing != NULL) {
2794 rlock_acquire(rtld_bind_lock, &lockstate);
2795 if (sigsetjmp(lockstate.env, 0) != 0)
2796 lock_upgrade(rtld_bind_lock, &lockstate);
2797 environ = (char **)*get_program_var_addr("environ", &lockstate);
2798 lock_release(rtld_bind_lock, &lockstate);
2800 lo_flags = RTLD_LO_DLOPEN;
2801 if (mode & RTLD_NODELETE)
2802 lo_flags |= RTLD_LO_NODELETE;
2803 if (mode & RTLD_NOLOAD)
2804 lo_flags |= RTLD_LO_NOLOAD;
2805 if (ld_tracing != NULL)
2806 lo_flags |= RTLD_LO_TRACE;
2808 return (dlopen_object(name, fd, obj_main, lo_flags,
2809 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
2813 dlopen_cleanup(Obj_Entry *obj)
2818 if (obj->refcount == 0)
2823 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2824 int mode, RtldLockState *lockstate)
2826 Obj_Entry **old_obj_tail;
2829 RtldLockState mlockstate;
2832 objlist_init(&initlist);
2834 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
2835 wlock_acquire(rtld_bind_lock, &mlockstate);
2836 lockstate = &mlockstate;
2838 GDB_STATE(RT_ADD,NULL);
2840 old_obj_tail = obj_tail;
2842 if (name == NULL && fd == -1) {
2846 obj = load_object(name, fd, refobj, lo_flags);
2851 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2852 objlist_push_tail(&list_global, obj);
2853 if (*old_obj_tail != NULL) { /* We loaded something new. */
2854 assert(*old_obj_tail == obj);
2855 result = load_needed_objects(obj,
2856 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
2860 result = rtld_verify_versions(&obj->dagmembers);
2861 if (result != -1 && ld_tracing)
2863 if (result == -1 || relocate_object_dag(obj,
2864 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
2865 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2867 dlopen_cleanup(obj);
2869 } else if (lo_flags & RTLD_LO_EARLY) {
2871 * Do not call the init functions for early loaded
2872 * filtees. The image is still not initialized enough
2875 * Our object is found by the global object list and
2876 * will be ordered among all init calls done right
2877 * before transferring control to main.
2880 /* Make list of init functions to call. */
2881 initlist_add_objects(obj, &obj->next, &initlist);
2884 * Process all no_delete objects here, given them own
2885 * DAGs to prevent their dependencies from being unloaded.
2886 * This has to be done after we have loaded all of the
2887 * dependencies, so that we do not miss any.
2890 process_nodelete(obj);
2893 * Bump the reference counts for objects on this DAG. If
2894 * this is the first dlopen() call for the object that was
2895 * already loaded as a dependency, initialize the dag
2901 if ((lo_flags & RTLD_LO_TRACE) != 0)
2904 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2905 obj->z_nodelete) && !obj->ref_nodel) {
2906 dbg("obj %s nodelete", obj->path);
2908 obj->z_nodelete = obj->ref_nodel = true;
2912 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2914 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2916 if (!(lo_flags & RTLD_LO_EARLY)) {
2917 map_stacks_exec(lockstate);
2920 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
2921 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2923 objlist_clear(&initlist);
2924 dlopen_cleanup(obj);
2925 if (lockstate == &mlockstate)
2926 lock_release(rtld_bind_lock, lockstate);
2930 if (!(lo_flags & RTLD_LO_EARLY)) {
2931 /* Call the init functions. */
2932 objlist_call_init(&initlist, lockstate);
2934 objlist_clear(&initlist);
2935 if (lockstate == &mlockstate)
2936 lock_release(rtld_bind_lock, lockstate);
2939 trace_loaded_objects(obj);
2940 if (lockstate == &mlockstate)
2941 lock_release(rtld_bind_lock, lockstate);
2946 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
2950 const Obj_Entry *obj, *defobj;
2953 RtldLockState lockstate;
2961 symlook_init(&req, name);
2963 req.flags = flags | SYMLOOK_IN_PLT;
2964 req.lockstate = &lockstate;
2966 rlock_acquire(rtld_bind_lock, &lockstate);
2967 if (sigsetjmp(lockstate.env, 0) != 0)
2968 lock_upgrade(rtld_bind_lock, &lockstate);
2969 if (handle == NULL || handle == RTLD_NEXT ||
2970 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
2972 if ((obj = obj_from_addr(retaddr)) == NULL) {
2973 _rtld_error("Cannot determine caller's shared object");
2974 lock_release(rtld_bind_lock, &lockstate);
2977 if (handle == NULL) { /* Just the caller's shared object. */
2978 res = symlook_obj(&req, obj);
2981 defobj = req.defobj_out;
2983 } else if (handle == RTLD_NEXT || /* Objects after caller's */
2984 handle == RTLD_SELF) { /* ... caller included */
2985 if (handle == RTLD_NEXT)
2987 for (; obj != NULL; obj = obj->next) {
2988 res = symlook_obj(&req, obj);
2991 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
2993 defobj = req.defobj_out;
2994 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3000 * Search the dynamic linker itself, and possibly resolve the
3001 * symbol from there. This is how the application links to
3002 * dynamic linker services such as dlopen.
3004 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3005 res = symlook_obj(&req, &obj_rtld);
3008 defobj = req.defobj_out;
3012 assert(handle == RTLD_DEFAULT);
3013 res = symlook_default(&req, obj);
3015 defobj = req.defobj_out;
3020 if ((obj = dlcheck(handle)) == NULL) {
3021 lock_release(rtld_bind_lock, &lockstate);
3025 donelist_init(&donelist);
3026 if (obj->mainprog) {
3027 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3028 res = symlook_global(&req, &donelist);
3031 defobj = req.defobj_out;
3034 * Search the dynamic linker itself, and possibly resolve the
3035 * symbol from there. This is how the application links to
3036 * dynamic linker services such as dlopen.
3038 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3039 res = symlook_obj(&req, &obj_rtld);
3042 defobj = req.defobj_out;
3047 /* Search the whole DAG rooted at the given object. */
3048 res = symlook_list(&req, &obj->dagmembers, &donelist);
3051 defobj = req.defobj_out;
3057 lock_release(rtld_bind_lock, &lockstate);
3060 * The value required by the caller is derived from the value
3061 * of the symbol. For the ia64 architecture, we need to
3062 * construct a function descriptor which the caller can use to
3063 * call the function with the right 'gp' value. For other
3064 * architectures and for non-functions, the value is simply
3065 * the relocated value of the symbol.
3067 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3068 return (make_function_pointer(def, defobj));
3069 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3070 return (rtld_resolve_ifunc(defobj, def));
3071 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3073 return (__tls_get_addr(defobj->tlsindex, def->st_value));
3075 ti.ti_module = defobj->tlsindex;
3076 ti.ti_offset = def->st_value;
3077 return (__tls_get_addr(&ti));
3080 return (defobj->relocbase + def->st_value);
3083 _rtld_error("Undefined symbol \"%s\"", name);
3084 lock_release(rtld_bind_lock, &lockstate);
3089 dlsym(void *handle, const char *name)
3091 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3096 dlfunc(void *handle, const char *name)
3103 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3109 dlvsym(void *handle, const char *name, const char *version)
3113 ventry.name = version;
3115 ventry.hash = elf_hash(version);
3117 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3122 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3124 const Obj_Entry *obj;
3125 RtldLockState lockstate;
3127 rlock_acquire(rtld_bind_lock, &lockstate);
3128 obj = obj_from_addr(addr);
3130 _rtld_error("No shared object contains address");
3131 lock_release(rtld_bind_lock, &lockstate);
3134 rtld_fill_dl_phdr_info(obj, phdr_info);
3135 lock_release(rtld_bind_lock, &lockstate);
3140 dladdr(const void *addr, Dl_info *info)
3142 const Obj_Entry *obj;
3145 unsigned long symoffset;
3146 RtldLockState lockstate;
3148 rlock_acquire(rtld_bind_lock, &lockstate);
3149 obj = obj_from_addr(addr);
3151 _rtld_error("No shared object contains address");
3152 lock_release(rtld_bind_lock, &lockstate);
3155 info->dli_fname = obj->path;
3156 info->dli_fbase = obj->mapbase;
3157 info->dli_saddr = (void *)0;
3158 info->dli_sname = NULL;
3161 * Walk the symbol list looking for the symbol whose address is
3162 * closest to the address sent in.
3164 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3165 def = obj->symtab + symoffset;
3168 * For skip the symbol if st_shndx is either SHN_UNDEF or
3171 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3175 * If the symbol is greater than the specified address, or if it
3176 * is further away from addr than the current nearest symbol,
3179 symbol_addr = obj->relocbase + def->st_value;
3180 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3183 /* Update our idea of the nearest symbol. */
3184 info->dli_sname = obj->strtab + def->st_name;
3185 info->dli_saddr = symbol_addr;
3188 if (info->dli_saddr == addr)
3191 lock_release(rtld_bind_lock, &lockstate);
3196 dlinfo(void *handle, int request, void *p)
3198 const Obj_Entry *obj;
3199 RtldLockState lockstate;
3202 rlock_acquire(rtld_bind_lock, &lockstate);
3204 if (handle == NULL || handle == RTLD_SELF) {
3207 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3208 if ((obj = obj_from_addr(retaddr)) == NULL)
3209 _rtld_error("Cannot determine caller's shared object");
3211 obj = dlcheck(handle);
3214 lock_release(rtld_bind_lock, &lockstate);
3220 case RTLD_DI_LINKMAP:
3221 *((struct link_map const **)p) = &obj->linkmap;
3223 case RTLD_DI_ORIGIN:
3224 error = rtld_dirname(obj->path, p);
3227 case RTLD_DI_SERINFOSIZE:
3228 case RTLD_DI_SERINFO:
3229 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3233 _rtld_error("Invalid request %d passed to dlinfo()", request);
3237 lock_release(rtld_bind_lock, &lockstate);
3243 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3246 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3247 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
3248 STAILQ_FIRST(&obj->names)->name : obj->path;
3249 phdr_info->dlpi_phdr = obj->phdr;
3250 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3251 phdr_info->dlpi_tls_modid = obj->tlsindex;
3252 phdr_info->dlpi_tls_data = obj->tlsinit;
3253 phdr_info->dlpi_adds = obj_loads;
3254 phdr_info->dlpi_subs = obj_loads - obj_count;
3258 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3260 struct dl_phdr_info phdr_info;
3261 const Obj_Entry *obj;
3262 RtldLockState bind_lockstate, phdr_lockstate;
3265 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3266 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3270 for (obj = obj_list; obj != NULL; obj = obj->next) {
3271 rtld_fill_dl_phdr_info(obj, &phdr_info);
3272 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3276 lock_release(rtld_bind_lock, &bind_lockstate);
3277 lock_release(rtld_phdr_lock, &phdr_lockstate);
3283 fill_search_info(const char *dir, size_t dirlen, void *param)
3285 struct fill_search_info_args *arg;
3289 if (arg->request == RTLD_DI_SERINFOSIZE) {
3290 arg->serinfo->dls_cnt ++;
3291 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3293 struct dl_serpath *s_entry;
3295 s_entry = arg->serpath;
3296 s_entry->dls_name = arg->strspace;
3297 s_entry->dls_flags = arg->flags;
3299 strncpy(arg->strspace, dir, dirlen);
3300 arg->strspace[dirlen] = '\0';
3302 arg->strspace += dirlen + 1;
3310 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3312 struct dl_serinfo _info;
3313 struct fill_search_info_args args;
3315 args.request = RTLD_DI_SERINFOSIZE;
3316 args.serinfo = &_info;
3318 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3321 path_enumerate(obj->rpath, fill_search_info, &args);
3322 path_enumerate(ld_library_path, fill_search_info, &args);
3323 path_enumerate(obj->runpath, fill_search_info, &args);
3324 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3325 if (!obj->z_nodeflib)
3326 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3329 if (request == RTLD_DI_SERINFOSIZE) {
3330 info->dls_size = _info.dls_size;
3331 info->dls_cnt = _info.dls_cnt;
3335 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3336 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3340 args.request = RTLD_DI_SERINFO;
3341 args.serinfo = info;
3342 args.serpath = &info->dls_serpath[0];
3343 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3345 args.flags = LA_SER_RUNPATH;
3346 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3349 args.flags = LA_SER_LIBPATH;
3350 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3353 args.flags = LA_SER_RUNPATH;
3354 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3357 args.flags = LA_SER_CONFIG;
3358 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3362 args.flags = LA_SER_DEFAULT;
3363 if (!obj->z_nodeflib &&
3364 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3370 rtld_dirname(const char *path, char *bname)
3374 /* Empty or NULL string gets treated as "." */
3375 if (path == NULL || *path == '\0') {
3381 /* Strip trailing slashes */
3382 endp = path + strlen(path) - 1;
3383 while (endp > path && *endp == '/')
3386 /* Find the start of the dir */
3387 while (endp > path && *endp != '/')
3390 /* Either the dir is "/" or there are no slashes */
3392 bname[0] = *endp == '/' ? '/' : '.';
3398 } while (endp > path && *endp == '/');
3401 if (endp - path + 2 > PATH_MAX)
3403 _rtld_error("Filename is too long: %s", path);
3407 strncpy(bname, path, endp - path + 1);
3408 bname[endp - path + 1] = '\0';
3413 rtld_dirname_abs(const char *path, char *base)
3415 char base_rel[PATH_MAX];
3417 if (rtld_dirname(path, base) == -1)
3421 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
3422 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
3423 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
3425 strcpy(base, base_rel);
3430 linkmap_add(Obj_Entry *obj)
3432 struct link_map *l = &obj->linkmap;
3433 struct link_map *prev;
3435 obj->linkmap.l_name = obj->path;
3436 obj->linkmap.l_addr = obj->mapbase;
3437 obj->linkmap.l_ld = obj->dynamic;
3439 /* GDB needs load offset on MIPS to use the symbols */
3440 obj->linkmap.l_offs = obj->relocbase;
3443 if (r_debug.r_map == NULL) {
3449 * Scan to the end of the list, but not past the entry for the
3450 * dynamic linker, which we want to keep at the very end.
3452 for (prev = r_debug.r_map;
3453 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3454 prev = prev->l_next)
3457 /* Link in the new entry. */
3459 l->l_next = prev->l_next;
3460 if (l->l_next != NULL)
3461 l->l_next->l_prev = l;
3466 linkmap_delete(Obj_Entry *obj)
3468 struct link_map *l = &obj->linkmap;
3470 if (l->l_prev == NULL) {
3471 if ((r_debug.r_map = l->l_next) != NULL)
3472 l->l_next->l_prev = NULL;
3476 if ((l->l_prev->l_next = l->l_next) != NULL)
3477 l->l_next->l_prev = l->l_prev;
3481 * Function for the debugger to set a breakpoint on to gain control.
3483 * The two parameters allow the debugger to easily find and determine
3484 * what the runtime loader is doing and to whom it is doing it.
3486 * When the loadhook trap is hit (r_debug_state, set at program
3487 * initialization), the arguments can be found on the stack:
3489 * +8 struct link_map *m
3490 * +4 struct r_debug *rd
3494 r_debug_state(struct r_debug* rd, struct link_map *m)
3497 * The following is a hack to force the compiler to emit calls to
3498 * this function, even when optimizing. If the function is empty,
3499 * the compiler is not obliged to emit any code for calls to it,
3500 * even when marked __noinline. However, gdb depends on those
3503 __asm __volatile("" : : : "memory");
3507 * Get address of the pointer variable in the main program.
3508 * Prefer non-weak symbol over the weak one.
3510 static const void **
3511 get_program_var_addr(const char *name, RtldLockState *lockstate)
3516 symlook_init(&req, name);
3517 req.lockstate = lockstate;
3518 donelist_init(&donelist);
3519 if (symlook_global(&req, &donelist) != 0)
3521 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3522 return ((const void **)make_function_pointer(req.sym_out,
3524 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3525 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3527 return ((const void **)(req.defobj_out->relocbase +
3528 req.sym_out->st_value));
3532 * Set a pointer variable in the main program to the given value. This
3533 * is used to set key variables such as "environ" before any of the
3534 * init functions are called.
3537 set_program_var(const char *name, const void *value)
3541 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3542 dbg("\"%s\": *%p <-- %p", name, addr, value);
3548 * Search the global objects, including dependencies and main object,
3549 * for the given symbol.
3552 symlook_global(SymLook *req, DoneList *donelist)
3555 const Objlist_Entry *elm;
3558 symlook_init_from_req(&req1, req);
3560 /* Search all objects loaded at program start up. */
3561 if (req->defobj_out == NULL ||
3562 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3563 res = symlook_list(&req1, &list_main, donelist);
3564 if (res == 0 && (req->defobj_out == NULL ||
3565 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3566 req->sym_out = req1.sym_out;
3567 req->defobj_out = req1.defobj_out;
3568 assert(req->defobj_out != NULL);
3572 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3573 STAILQ_FOREACH(elm, &list_global, link) {
3574 if (req->defobj_out != NULL &&
3575 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3577 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3578 if (res == 0 && (req->defobj_out == NULL ||
3579 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3580 req->sym_out = req1.sym_out;
3581 req->defobj_out = req1.defobj_out;
3582 assert(req->defobj_out != NULL);
3586 return (req->sym_out != NULL ? 0 : ESRCH);
3590 * Given a symbol name in a referencing object, find the corresponding
3591 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3592 * no definition was found. Returns a pointer to the Obj_Entry of the
3593 * defining object via the reference parameter DEFOBJ_OUT.
3596 symlook_default(SymLook *req, const Obj_Entry *refobj)
3599 const Objlist_Entry *elm;
3603 donelist_init(&donelist);
3604 symlook_init_from_req(&req1, req);
3606 /* Look first in the referencing object if linked symbolically. */
3607 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3608 res = symlook_obj(&req1, refobj);
3610 req->sym_out = req1.sym_out;
3611 req->defobj_out = req1.defobj_out;
3612 assert(req->defobj_out != NULL);
3616 symlook_global(req, &donelist);
3618 /* Search all dlopened DAGs containing the referencing object. */
3619 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3620 if (req->sym_out != NULL &&
3621 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3623 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3624 if (res == 0 && (req->sym_out == NULL ||
3625 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3626 req->sym_out = req1.sym_out;
3627 req->defobj_out = req1.defobj_out;
3628 assert(req->defobj_out != NULL);
3633 * Search the dynamic linker itself, and possibly resolve the
3634 * symbol from there. This is how the application links to
3635 * dynamic linker services such as dlopen.
3637 if (req->sym_out == NULL ||
3638 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3639 res = symlook_obj(&req1, &obj_rtld);
3641 req->sym_out = req1.sym_out;
3642 req->defobj_out = req1.defobj_out;
3643 assert(req->defobj_out != NULL);
3647 return (req->sym_out != NULL ? 0 : ESRCH);
3651 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3654 const Obj_Entry *defobj;
3655 const Objlist_Entry *elm;
3661 STAILQ_FOREACH(elm, objlist, link) {
3662 if (donelist_check(dlp, elm->obj))
3664 symlook_init_from_req(&req1, req);
3665 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3666 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3668 defobj = req1.defobj_out;
3669 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3676 req->defobj_out = defobj;
3683 * Search the chain of DAGS cointed to by the given Needed_Entry
3684 * for a symbol of the given name. Each DAG is scanned completely
3685 * before advancing to the next one. Returns a pointer to the symbol,
3686 * or NULL if no definition was found.
3689 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3692 const Needed_Entry *n;
3693 const Obj_Entry *defobj;
3699 symlook_init_from_req(&req1, req);
3700 for (n = needed; n != NULL; n = n->next) {
3701 if (n->obj == NULL ||
3702 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3704 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3706 defobj = req1.defobj_out;
3707 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3713 req->defobj_out = defobj;
3720 * Search the symbol table of a single shared object for a symbol of
3721 * the given name and version, if requested. Returns a pointer to the
3722 * symbol, or NULL if no definition was found. If the object is
3723 * filter, return filtered symbol from filtee.
3725 * The symbol's hash value is passed in for efficiency reasons; that
3726 * eliminates many recomputations of the hash value.
3729 symlook_obj(SymLook *req, const Obj_Entry *obj)
3733 int flags, res, mres;
3736 * If there is at least one valid hash at this point, we prefer to
3737 * use the faster GNU version if available.
3739 if (obj->valid_hash_gnu)
3740 mres = symlook_obj1_gnu(req, obj);
3741 else if (obj->valid_hash_sysv)
3742 mres = symlook_obj1_sysv(req, obj);
3747 if (obj->needed_filtees != NULL) {
3748 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3749 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3750 donelist_init(&donelist);
3751 symlook_init_from_req(&req1, req);
3752 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3754 req->sym_out = req1.sym_out;
3755 req->defobj_out = req1.defobj_out;
3759 if (obj->needed_aux_filtees != NULL) {
3760 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3761 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3762 donelist_init(&donelist);
3763 symlook_init_from_req(&req1, req);
3764 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3766 req->sym_out = req1.sym_out;
3767 req->defobj_out = req1.defobj_out;
3775 /* Symbol match routine common to both hash functions */
3777 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3778 const unsigned long symnum)
3781 const Elf_Sym *symp;
3784 symp = obj->symtab + symnum;
3785 strp = obj->strtab + symp->st_name;
3787 switch (ELF_ST_TYPE(symp->st_info)) {
3793 if (symp->st_value == 0)
3797 if (symp->st_shndx != SHN_UNDEF)
3800 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3801 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3808 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3811 if (req->ventry == NULL) {
3812 if (obj->versyms != NULL) {
3813 verndx = VER_NDX(obj->versyms[symnum]);
3814 if (verndx > obj->vernum) {
3816 "%s: symbol %s references wrong version %d",
3817 obj->path, obj->strtab + symnum, verndx);
3821 * If we are not called from dlsym (i.e. this
3822 * is a normal relocation from unversioned
3823 * binary), accept the symbol immediately if
3824 * it happens to have first version after this
3825 * shared object became versioned. Otherwise,
3826 * if symbol is versioned and not hidden,
3827 * remember it. If it is the only symbol with
3828 * this name exported by the shared object, it
3829 * will be returned as a match by the calling
3830 * function. If symbol is global (verndx < 2)
3831 * accept it unconditionally.
3833 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3834 verndx == VER_NDX_GIVEN) {
3835 result->sym_out = symp;
3838 else if (verndx >= VER_NDX_GIVEN) {
3839 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
3841 if (result->vsymp == NULL)
3842 result->vsymp = symp;
3848 result->sym_out = symp;
3851 if (obj->versyms == NULL) {
3852 if (object_match_name(obj, req->ventry->name)) {
3853 _rtld_error("%s: object %s should provide version %s "
3854 "for symbol %s", obj_rtld.path, obj->path,
3855 req->ventry->name, obj->strtab + symnum);
3859 verndx = VER_NDX(obj->versyms[symnum]);
3860 if (verndx > obj->vernum) {
3861 _rtld_error("%s: symbol %s references wrong version %d",
3862 obj->path, obj->strtab + symnum, verndx);
3865 if (obj->vertab[verndx].hash != req->ventry->hash ||
3866 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3868 * Version does not match. Look if this is a
3869 * global symbol and if it is not hidden. If
3870 * global symbol (verndx < 2) is available,
3871 * use it. Do not return symbol if we are
3872 * called by dlvsym, because dlvsym looks for
3873 * a specific version and default one is not
3874 * what dlvsym wants.
3876 if ((req->flags & SYMLOOK_DLSYM) ||
3877 (verndx >= VER_NDX_GIVEN) ||
3878 (obj->versyms[symnum] & VER_NDX_HIDDEN))
3882 result->sym_out = symp;
3887 * Search for symbol using SysV hash function.
3888 * obj->buckets is known not to be NULL at this point; the test for this was
3889 * performed with the obj->valid_hash_sysv assignment.
3892 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
3894 unsigned long symnum;
3895 Sym_Match_Result matchres;
3897 matchres.sym_out = NULL;
3898 matchres.vsymp = NULL;
3899 matchres.vcount = 0;
3901 for (symnum = obj->buckets[req->hash % obj->nbuckets];
3902 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
3903 if (symnum >= obj->nchains)
3904 return (ESRCH); /* Bad object */
3906 if (matched_symbol(req, obj, &matchres, symnum)) {
3907 req->sym_out = matchres.sym_out;
3908 req->defobj_out = obj;
3912 if (matchres.vcount == 1) {
3913 req->sym_out = matchres.vsymp;
3914 req->defobj_out = obj;
3920 /* Search for symbol using GNU hash function */
3922 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
3924 Elf_Addr bloom_word;
3925 const Elf32_Word *hashval;
3927 Sym_Match_Result matchres;
3928 unsigned int h1, h2;
3929 unsigned long symnum;
3931 matchres.sym_out = NULL;
3932 matchres.vsymp = NULL;
3933 matchres.vcount = 0;
3935 /* Pick right bitmask word from Bloom filter array */
3936 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
3937 obj->maskwords_bm_gnu];
3939 /* Calculate modulus word size of gnu hash and its derivative */
3940 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
3941 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
3943 /* Filter out the "definitely not in set" queries */
3944 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
3947 /* Locate hash chain and corresponding value element*/
3948 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
3951 hashval = &obj->chain_zero_gnu[bucket];
3953 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
3954 symnum = hashval - obj->chain_zero_gnu;
3955 if (matched_symbol(req, obj, &matchres, symnum)) {
3956 req->sym_out = matchres.sym_out;
3957 req->defobj_out = obj;
3961 } while ((*hashval++ & 1) == 0);
3962 if (matchres.vcount == 1) {
3963 req->sym_out = matchres.vsymp;
3964 req->defobj_out = obj;
3971 trace_loaded_objects(Obj_Entry *obj)
3973 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
3976 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
3979 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
3980 fmt1 = "\t%o => %p (%x)\n";
3982 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
3983 fmt2 = "\t%o (%x)\n";
3985 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
3987 for (; obj; obj = obj->next) {
3988 Needed_Entry *needed;
3992 if (list_containers && obj->needed != NULL)
3993 rtld_printf("%s:\n", obj->path);
3994 for (needed = obj->needed; needed; needed = needed->next) {
3995 if (needed->obj != NULL) {
3996 if (needed->obj->traced && !list_containers)
3998 needed->obj->traced = true;
3999 path = needed->obj->path;
4003 name = (char *)obj->strtab + needed->name;
4004 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4006 fmt = is_lib ? fmt1 : fmt2;
4007 while ((c = *fmt++) != '\0') {
4033 rtld_putstr(main_local);
4036 rtld_putstr(obj_main->path);
4043 rtld_printf("%d", sodp->sod_major);
4046 rtld_printf("%d", sodp->sod_minor);
4053 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4066 * Unload a dlopened object and its dependencies from memory and from
4067 * our data structures. It is assumed that the DAG rooted in the
4068 * object has already been unreferenced, and that the object has a
4069 * reference count of 0.
4072 unload_object(Obj_Entry *root)
4077 assert(root->refcount == 0);
4080 * Pass over the DAG removing unreferenced objects from
4081 * appropriate lists.
4083 unlink_object(root);
4085 /* Unmap all objects that are no longer referenced. */
4086 linkp = &obj_list->next;
4087 while ((obj = *linkp) != NULL) {
4088 if (obj->refcount == 0) {
4089 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4091 dbg("unloading \"%s\"", obj->path);
4092 unload_filtees(root);
4093 munmap(obj->mapbase, obj->mapsize);
4094 linkmap_delete(obj);
4105 unlink_object(Obj_Entry *root)
4109 if (root->refcount == 0) {
4110 /* Remove the object from the RTLD_GLOBAL list. */
4111 objlist_remove(&list_global, root);
4113 /* Remove the object from all objects' DAG lists. */
4114 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4115 objlist_remove(&elm->obj->dldags, root);
4116 if (elm->obj != root)
4117 unlink_object(elm->obj);
4123 ref_dag(Obj_Entry *root)
4127 assert(root->dag_inited);
4128 STAILQ_FOREACH(elm, &root->dagmembers, link)
4129 elm->obj->refcount++;
4133 unref_dag(Obj_Entry *root)
4137 assert(root->dag_inited);
4138 STAILQ_FOREACH(elm, &root->dagmembers, link)
4139 elm->obj->refcount--;
4143 * Common code for MD __tls_get_addr().
4145 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4147 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4149 Elf_Addr *newdtv, *dtv;
4150 RtldLockState lockstate;
4154 /* Check dtv generation in case new modules have arrived */
4155 if (dtv[0] != tls_dtv_generation) {
4156 wlock_acquire(rtld_bind_lock, &lockstate);
4157 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4159 if (to_copy > tls_max_index)
4160 to_copy = tls_max_index;
4161 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4162 newdtv[0] = tls_dtv_generation;
4163 newdtv[1] = tls_max_index;
4165 lock_release(rtld_bind_lock, &lockstate);
4166 dtv = *dtvp = newdtv;
4169 /* Dynamically allocate module TLS if necessary */
4170 if (dtv[index + 1] == 0) {
4171 /* Signal safe, wlock will block out signals. */
4172 wlock_acquire(rtld_bind_lock, &lockstate);
4173 if (!dtv[index + 1])
4174 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4175 lock_release(rtld_bind_lock, &lockstate);
4177 return ((void *)(dtv[index + 1] + offset));
4181 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4186 /* Check dtv generation in case new modules have arrived */
4187 if (__predict_true(dtv[0] == tls_dtv_generation &&
4188 dtv[index + 1] != 0))
4189 return ((void *)(dtv[index + 1] + offset));
4190 return (tls_get_addr_slow(dtvp, index, offset));
4193 #if defined(__arm__) || defined(__ia64__) || defined(__powerpc__)
4196 * Allocate Static TLS using the Variant I method.
4199 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4208 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4211 assert(tcbsize >= TLS_TCB_SIZE);
4212 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4213 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4215 if (oldtcb != NULL) {
4216 memcpy(tls, oldtcb, tls_static_space);
4219 /* Adjust the DTV. */
4221 for (i = 0; i < dtv[1]; i++) {
4222 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4223 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4224 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4228 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4230 dtv[0] = tls_dtv_generation;
4231 dtv[1] = tls_max_index;
4233 for (obj = objs; obj; obj = obj->next) {
4234 if (obj->tlsoffset > 0) {
4235 addr = (Elf_Addr)tls + obj->tlsoffset;
4236 if (obj->tlsinitsize > 0)
4237 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4238 if (obj->tlssize > obj->tlsinitsize)
4239 memset((void*) (addr + obj->tlsinitsize), 0,
4240 obj->tlssize - obj->tlsinitsize);
4241 dtv[obj->tlsindex + 1] = addr;
4250 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4253 Elf_Addr tlsstart, tlsend;
4256 assert(tcbsize >= TLS_TCB_SIZE);
4258 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4259 tlsend = tlsstart + tls_static_space;
4261 dtv = *(Elf_Addr **)tlsstart;
4263 for (i = 0; i < dtvsize; i++) {
4264 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4265 free((void*)dtv[i+2]);
4274 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \
4278 * Allocate Static TLS using the Variant II method.
4281 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4286 Elf_Addr *dtv, *olddtv;
4287 Elf_Addr segbase, oldsegbase, addr;
4290 size = round(tls_static_space, tcbalign);
4292 assert(tcbsize >= 2*sizeof(Elf_Addr));
4293 tls = xcalloc(1, size + tcbsize);
4294 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4296 segbase = (Elf_Addr)(tls + size);
4297 ((Elf_Addr*)segbase)[0] = segbase;
4298 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4300 dtv[0] = tls_dtv_generation;
4301 dtv[1] = tls_max_index;
4305 * Copy the static TLS block over whole.
4307 oldsegbase = (Elf_Addr) oldtls;
4308 memcpy((void *)(segbase - tls_static_space),
4309 (const void *)(oldsegbase - tls_static_space),
4313 * If any dynamic TLS blocks have been created tls_get_addr(),
4316 olddtv = ((Elf_Addr**)oldsegbase)[1];
4317 for (i = 0; i < olddtv[1]; i++) {
4318 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4319 dtv[i+2] = olddtv[i+2];
4325 * We assume that this block was the one we created with
4326 * allocate_initial_tls().
4328 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4330 for (obj = objs; obj; obj = obj->next) {
4331 if (obj->tlsoffset) {
4332 addr = segbase - obj->tlsoffset;
4333 memset((void*) (addr + obj->tlsinitsize),
4334 0, obj->tlssize - obj->tlsinitsize);
4336 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4337 dtv[obj->tlsindex + 1] = addr;
4342 return (void*) segbase;
4346 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4351 Elf_Addr tlsstart, tlsend;
4354 * Figure out the size of the initial TLS block so that we can
4355 * find stuff which ___tls_get_addr() allocated dynamically.
4357 size = round(tls_static_space, tcbalign);
4359 dtv = ((Elf_Addr**)tls)[1];
4361 tlsend = (Elf_Addr) tls;
4362 tlsstart = tlsend - size;
4363 for (i = 0; i < dtvsize; i++) {
4364 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) {
4365 free((void*) dtv[i+2]);
4369 free((void*) tlsstart);
4376 * Allocate TLS block for module with given index.
4379 allocate_module_tls(int index)
4384 for (obj = obj_list; obj; obj = obj->next) {
4385 if (obj->tlsindex == index)
4389 _rtld_error("Can't find module with TLS index %d", index);
4393 p = malloc(obj->tlssize);
4395 _rtld_error("Cannot allocate TLS block for index %d", index);
4398 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4399 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4405 allocate_tls_offset(Obj_Entry *obj)
4412 if (obj->tlssize == 0) {
4413 obj->tls_done = true;
4417 if (obj->tlsindex == 1)
4418 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4420 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4421 obj->tlssize, obj->tlsalign);
4424 * If we have already fixed the size of the static TLS block, we
4425 * must stay within that size. When allocating the static TLS, we
4426 * leave a small amount of space spare to be used for dynamically
4427 * loading modules which use static TLS.
4429 if (tls_static_space) {
4430 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4434 tls_last_offset = obj->tlsoffset = off;
4435 tls_last_size = obj->tlssize;
4436 obj->tls_done = true;
4442 free_tls_offset(Obj_Entry *obj)
4446 * If we were the last thing to allocate out of the static TLS
4447 * block, we give our space back to the 'allocator'. This is a
4448 * simplistic workaround to allow libGL.so.1 to be loaded and
4449 * unloaded multiple times.
4451 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4452 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4453 tls_last_offset -= obj->tlssize;
4459 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4462 RtldLockState lockstate;
4464 wlock_acquire(rtld_bind_lock, &lockstate);
4465 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4466 lock_release(rtld_bind_lock, &lockstate);
4471 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4473 RtldLockState lockstate;
4475 wlock_acquire(rtld_bind_lock, &lockstate);
4476 free_tls(tcb, tcbsize, tcbalign);
4477 lock_release(rtld_bind_lock, &lockstate);
4481 object_add_name(Obj_Entry *obj, const char *name)
4487 entry = malloc(sizeof(Name_Entry) + len);
4489 if (entry != NULL) {
4490 strcpy(entry->name, name);
4491 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4496 object_match_name(const Obj_Entry *obj, const char *name)
4500 STAILQ_FOREACH(entry, &obj->names, link) {
4501 if (strcmp(name, entry->name) == 0)
4508 locate_dependency(const Obj_Entry *obj, const char *name)
4510 const Objlist_Entry *entry;
4511 const Needed_Entry *needed;
4513 STAILQ_FOREACH(entry, &list_main, link) {
4514 if (object_match_name(entry->obj, name))
4518 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4519 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4520 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4522 * If there is DT_NEEDED for the name we are looking for,
4523 * we are all set. Note that object might not be found if
4524 * dependency was not loaded yet, so the function can
4525 * return NULL here. This is expected and handled
4526 * properly by the caller.
4528 return (needed->obj);
4531 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4537 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4538 const Elf_Vernaux *vna)
4540 const Elf_Verdef *vd;
4541 const char *vername;
4543 vername = refobj->strtab + vna->vna_name;
4544 vd = depobj->verdef;
4546 _rtld_error("%s: version %s required by %s not defined",
4547 depobj->path, vername, refobj->path);
4551 if (vd->vd_version != VER_DEF_CURRENT) {
4552 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4553 depobj->path, vd->vd_version);
4556 if (vna->vna_hash == vd->vd_hash) {
4557 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4558 ((char *)vd + vd->vd_aux);
4559 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4562 if (vd->vd_next == 0)
4564 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4566 if (vna->vna_flags & VER_FLG_WEAK)
4568 _rtld_error("%s: version %s required by %s not found",
4569 depobj->path, vername, refobj->path);
4574 rtld_verify_object_versions(Obj_Entry *obj)
4576 const Elf_Verneed *vn;
4577 const Elf_Verdef *vd;
4578 const Elf_Verdaux *vda;
4579 const Elf_Vernaux *vna;
4580 const Obj_Entry *depobj;
4581 int maxvernum, vernum;
4583 if (obj->ver_checked)
4585 obj->ver_checked = true;
4589 * Walk over defined and required version records and figure out
4590 * max index used by any of them. Do very basic sanity checking
4594 while (vn != NULL) {
4595 if (vn->vn_version != VER_NEED_CURRENT) {
4596 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4597 obj->path, vn->vn_version);
4600 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4602 vernum = VER_NEED_IDX(vna->vna_other);
4603 if (vernum > maxvernum)
4605 if (vna->vna_next == 0)
4607 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4609 if (vn->vn_next == 0)
4611 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4615 while (vd != NULL) {
4616 if (vd->vd_version != VER_DEF_CURRENT) {
4617 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4618 obj->path, vd->vd_version);
4621 vernum = VER_DEF_IDX(vd->vd_ndx);
4622 if (vernum > maxvernum)
4624 if (vd->vd_next == 0)
4626 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4633 * Store version information in array indexable by version index.
4634 * Verify that object version requirements are satisfied along the
4637 obj->vernum = maxvernum + 1;
4638 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4641 while (vd != NULL) {
4642 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4643 vernum = VER_DEF_IDX(vd->vd_ndx);
4644 assert(vernum <= maxvernum);
4645 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4646 obj->vertab[vernum].hash = vd->vd_hash;
4647 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4648 obj->vertab[vernum].file = NULL;
4649 obj->vertab[vernum].flags = 0;
4651 if (vd->vd_next == 0)
4653 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4657 while (vn != NULL) {
4658 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4661 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4663 if (check_object_provided_version(obj, depobj, vna))
4665 vernum = VER_NEED_IDX(vna->vna_other);
4666 assert(vernum <= maxvernum);
4667 obj->vertab[vernum].hash = vna->vna_hash;
4668 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4669 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4670 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4671 VER_INFO_HIDDEN : 0;
4672 if (vna->vna_next == 0)
4674 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4676 if (vn->vn_next == 0)
4678 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4684 rtld_verify_versions(const Objlist *objlist)
4686 Objlist_Entry *entry;
4690 STAILQ_FOREACH(entry, objlist, link) {
4692 * Skip dummy objects or objects that have their version requirements
4695 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4697 if (rtld_verify_object_versions(entry->obj) == -1) {
4699 if (ld_tracing == NULL)
4703 if (rc == 0 || ld_tracing != NULL)
4704 rc = rtld_verify_object_versions(&obj_rtld);
4709 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4714 vernum = VER_NDX(obj->versyms[symnum]);
4715 if (vernum >= obj->vernum) {
4716 _rtld_error("%s: symbol %s has wrong verneed value %d",
4717 obj->path, obj->strtab + symnum, vernum);
4718 } else if (obj->vertab[vernum].hash != 0) {
4719 return &obj->vertab[vernum];
4726 _rtld_get_stack_prot(void)
4729 return (stack_prot);
4733 map_stacks_exec(RtldLockState *lockstate)
4735 void (*thr_map_stacks_exec)(void);
4737 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4739 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4740 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4741 if (thr_map_stacks_exec != NULL) {
4742 stack_prot |= PROT_EXEC;
4743 thr_map_stacks_exec();
4748 symlook_init(SymLook *dst, const char *name)
4751 bzero(dst, sizeof(*dst));
4753 dst->hash = elf_hash(name);
4754 dst->hash_gnu = gnu_hash(name);
4758 symlook_init_from_req(SymLook *dst, const SymLook *src)
4761 dst->name = src->name;
4762 dst->hash = src->hash;
4763 dst->hash_gnu = src->hash_gnu;
4764 dst->ventry = src->ventry;
4765 dst->flags = src->flags;
4766 dst->defobj_out = NULL;
4767 dst->sym_out = NULL;
4768 dst->lockstate = src->lockstate;
4772 * Overrides for libc_pic-provided functions.
4776 __getosreldate(void)
4786 oid[1] = KERN_OSRELDATE;
4788 len = sizeof(osrel);
4789 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4790 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4802 void (*__cleanup)(void);
4803 int __isthreaded = 0;
4804 int _thread_autoinit_dummy_decl = 1;
4807 * No unresolved symbols for rtld.
4810 __pthread_cxa_finalize(struct dl_phdr_info *a)
4815 __stack_chk_fail(void)
4818 _rtld_error("stack overflow detected; terminated");
4821 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
4827 _rtld_error("buffer overflow detected; terminated");
4832 rtld_strerror(int errnum)
4835 if (errnum < 0 || errnum >= sys_nerr)
4836 return ("Unknown error");
4837 return (sys_errlist[errnum]);