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;
164 void _r_debug_postinit(struct link_map *) __noinline;
169 static char *error_message; /* Message for dlerror(), or NULL */
170 struct r_debug r_debug; /* for GDB; */
171 static bool libmap_disable; /* Disable libmap */
172 static bool ld_loadfltr; /* Immediate filters processing */
173 static char *libmap_override; /* Maps to use in addition to libmap.conf */
174 static bool trust; /* False for setuid and setgid programs */
175 static bool dangerous_ld_env; /* True if environment variables have been
176 used to affect the libraries loaded */
177 static char *ld_bind_now; /* Environment variable for immediate binding */
178 static char *ld_debug; /* Environment variable for debugging */
179 static char *ld_library_path; /* Environment variable for search path */
180 static char *ld_preload; /* Environment variable for libraries to
182 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
183 static char *ld_tracing; /* Called from ldd to print libs */
184 static char *ld_utrace; /* Use utrace() to log events. */
185 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
186 static Obj_Entry **obj_tail; /* Link field of last object in list */
187 static Obj_Entry *obj_main; /* The main program shared object */
188 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
189 static unsigned int obj_count; /* Number of objects in obj_list */
190 static unsigned int obj_loads; /* Number of objects in obj_list */
192 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
193 STAILQ_HEAD_INITIALIZER(list_global);
194 static Objlist list_main = /* Objects loaded at program startup */
195 STAILQ_HEAD_INITIALIZER(list_main);
196 static Objlist list_fini = /* Objects needing fini() calls */
197 STAILQ_HEAD_INITIALIZER(list_fini);
199 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
201 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
203 extern Elf_Dyn _DYNAMIC;
204 #pragma weak _DYNAMIC
205 #ifndef RTLD_IS_DYNAMIC
206 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
209 int osreldate, pagesize;
211 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
213 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
214 static int max_stack_flags;
217 * Global declarations normally provided by crt1. The dynamic linker is
218 * not built with crt1, so we have to provide them ourselves.
224 * Used to pass argc, argv to init functions.
230 * Globals to control TLS allocation.
232 size_t tls_last_offset; /* Static TLS offset of last module */
233 size_t tls_last_size; /* Static TLS size of last module */
234 size_t tls_static_space; /* Static TLS space allocated */
235 size_t tls_static_max_align;
236 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
237 int tls_max_index = 1; /* Largest module index allocated */
239 bool ld_library_path_rpath = true;
242 * Fill in a DoneList with an allocation large enough to hold all of
243 * the currently-loaded objects. Keep this as a macro since it calls
244 * alloca and we want that to occur within the scope of the caller.
246 #define donelist_init(dlp) \
247 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
248 assert((dlp)->objs != NULL), \
249 (dlp)->num_alloc = obj_count, \
252 #define UTRACE_DLOPEN_START 1
253 #define UTRACE_DLOPEN_STOP 2
254 #define UTRACE_DLCLOSE_START 3
255 #define UTRACE_DLCLOSE_STOP 4
256 #define UTRACE_LOAD_OBJECT 5
257 #define UTRACE_UNLOAD_OBJECT 6
258 #define UTRACE_ADD_RUNDEP 7
259 #define UTRACE_PRELOAD_FINISHED 8
260 #define UTRACE_INIT_CALL 9
261 #define UTRACE_FINI_CALL 10
262 #define UTRACE_DLSYM_START 11
263 #define UTRACE_DLSYM_STOP 12
266 char sig[4]; /* 'RTLD' */
269 void *mapbase; /* Used for 'parent' and 'init/fini' */
271 int refcnt; /* Used for 'mode' */
272 char name[MAXPATHLEN];
275 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
276 if (ld_utrace != NULL) \
277 ld_utrace_log(e, h, mb, ms, r, n); \
281 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
282 int refcnt, const char *name)
284 struct utrace_rtld ut;
292 ut.mapbase = mapbase;
293 ut.mapsize = mapsize;
295 bzero(ut.name, sizeof(ut.name));
297 strlcpy(ut.name, name, sizeof(ut.name));
298 utrace(&ut, sizeof(ut));
302 * Main entry point for dynamic linking. The first argument is the
303 * stack pointer. The stack is expected to be laid out as described
304 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
305 * Specifically, the stack pointer points to a word containing
306 * ARGC. Following that in the stack is a null-terminated sequence
307 * of pointers to argument strings. Then comes a null-terminated
308 * sequence of pointers to environment strings. Finally, there is a
309 * sequence of "auxiliary vector" entries.
311 * The second argument points to a place to store the dynamic linker's
312 * exit procedure pointer and the third to a place to store the main
315 * The return value is the main program's entry point.
318 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
320 Elf_Auxinfo *aux_info[AT_COUNT];
328 Objlist_Entry *entry;
330 Obj_Entry **preload_tail;
331 Obj_Entry *last_interposer;
333 RtldLockState lockstate;
334 char *library_path_rpath;
339 * On entry, the dynamic linker itself has not been relocated yet.
340 * Be very careful not to reference any global data until after
341 * init_rtld has returned. It is OK to reference file-scope statics
342 * and string constants, and to call static and global functions.
345 /* Find the auxiliary vector on the stack. */
348 sp += argc + 1; /* Skip over arguments and NULL terminator */
350 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
352 aux = (Elf_Auxinfo *) sp;
354 /* Digest the auxiliary vector. */
355 for (i = 0; i < AT_COUNT; i++)
357 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
358 if (auxp->a_type < AT_COUNT)
359 aux_info[auxp->a_type] = auxp;
362 /* Initialize and relocate ourselves. */
363 assert(aux_info[AT_BASE] != NULL);
364 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
366 __progname = obj_rtld.path;
367 argv0 = argv[0] != NULL ? argv[0] : "(null)";
372 if (aux_info[AT_CANARY] != NULL &&
373 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
374 i = aux_info[AT_CANARYLEN]->a_un.a_val;
375 if (i > sizeof(__stack_chk_guard))
376 i = sizeof(__stack_chk_guard);
377 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
382 len = sizeof(__stack_chk_guard);
383 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
384 len != sizeof(__stack_chk_guard)) {
385 /* If sysctl was unsuccessful, use the "terminator canary". */
386 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
387 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
388 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
389 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
393 trust = !issetugid();
395 ld_bind_now = getenv(LD_ "BIND_NOW");
397 * If the process is tainted, then we un-set the dangerous environment
398 * variables. The process will be marked as tainted until setuid(2)
399 * is called. If any child process calls setuid(2) we do not want any
400 * future processes to honor the potentially un-safe variables.
403 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
404 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") ||
405 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
406 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) {
407 _rtld_error("environment corrupt; aborting");
411 ld_debug = getenv(LD_ "DEBUG");
412 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
413 libmap_override = getenv(LD_ "LIBMAP");
414 ld_library_path = getenv(LD_ "LIBRARY_PATH");
415 ld_preload = getenv(LD_ "PRELOAD");
416 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
417 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
418 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH");
419 if (library_path_rpath != NULL) {
420 if (library_path_rpath[0] == 'y' ||
421 library_path_rpath[0] == 'Y' ||
422 library_path_rpath[0] == '1')
423 ld_library_path_rpath = true;
425 ld_library_path_rpath = false;
427 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
428 (ld_library_path != NULL) || (ld_preload != NULL) ||
429 (ld_elf_hints_path != NULL) || ld_loadfltr;
430 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
431 ld_utrace = getenv(LD_ "UTRACE");
433 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
434 ld_elf_hints_path = _PATH_ELF_HINTS;
436 if (ld_debug != NULL && *ld_debug != '\0')
438 dbg("%s is initialized, base address = %p", __progname,
439 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
440 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
441 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
443 dbg("initializing thread locks");
447 * Load the main program, or process its program header if it is
450 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
451 int fd = aux_info[AT_EXECFD]->a_un.a_val;
452 dbg("loading main program");
453 obj_main = map_object(fd, argv0, NULL);
455 if (obj_main == NULL)
457 max_stack_flags = obj->stack_flags;
458 } else { /* Main program already loaded. */
459 const Elf_Phdr *phdr;
463 dbg("processing main program's program header");
464 assert(aux_info[AT_PHDR] != NULL);
465 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
466 assert(aux_info[AT_PHNUM] != NULL);
467 phnum = aux_info[AT_PHNUM]->a_un.a_val;
468 assert(aux_info[AT_PHENT] != NULL);
469 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
470 assert(aux_info[AT_ENTRY] != NULL);
471 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
472 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
476 if (aux_info[AT_EXECPATH] != 0) {
478 char buf[MAXPATHLEN];
480 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
481 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
482 if (kexecpath[0] == '/')
483 obj_main->path = kexecpath;
484 else if (getcwd(buf, sizeof(buf)) == NULL ||
485 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
486 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
487 obj_main->path = xstrdup(argv0);
489 obj_main->path = xstrdup(buf);
491 dbg("No AT_EXECPATH");
492 obj_main->path = xstrdup(argv0);
494 dbg("obj_main path %s", obj_main->path);
495 obj_main->mainprog = true;
497 if (aux_info[AT_STACKPROT] != NULL &&
498 aux_info[AT_STACKPROT]->a_un.a_val != 0)
499 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
502 * Get the actual dynamic linker pathname from the executable if
503 * possible. (It should always be possible.) That ensures that
504 * gdb will find the right dynamic linker even if a non-standard
507 if (obj_main->interp != NULL &&
508 strcmp(obj_main->interp, obj_rtld.path) != 0) {
510 obj_rtld.path = xstrdup(obj_main->interp);
511 __progname = obj_rtld.path;
514 digest_dynamic(obj_main, 0);
515 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
516 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
517 obj_main->dynsymcount);
519 linkmap_add(obj_main);
520 linkmap_add(&obj_rtld);
522 /* Link the main program into the list of objects. */
523 *obj_tail = obj_main;
524 obj_tail = &obj_main->next;
528 /* Initialize a fake symbol for resolving undefined weak references. */
529 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
530 sym_zero.st_shndx = SHN_UNDEF;
531 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
534 libmap_disable = (bool)lm_init(libmap_override);
536 dbg("loading LD_PRELOAD libraries");
537 if (load_preload_objects() == -1)
539 preload_tail = obj_tail;
541 dbg("loading needed objects");
542 if (load_needed_objects(obj_main, 0) == -1)
545 /* Make a list of all objects loaded at startup. */
546 last_interposer = obj_main;
547 for (obj = obj_list; obj != NULL; obj = obj->next) {
548 if (obj->z_interpose && obj != obj_main) {
549 objlist_put_after(&list_main, last_interposer, obj);
550 last_interposer = obj;
552 objlist_push_tail(&list_main, obj);
557 dbg("checking for required versions");
558 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
561 if (ld_tracing) { /* We're done */
562 trace_loaded_objects(obj_main);
566 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
567 dump_relocations(obj_main);
572 * Processing tls relocations requires having the tls offsets
573 * initialized. Prepare offsets before starting initial
574 * relocation processing.
576 dbg("initializing initial thread local storage offsets");
577 STAILQ_FOREACH(entry, &list_main, link) {
579 * Allocate all the initial objects out of the static TLS
580 * block even if they didn't ask for it.
582 allocate_tls_offset(entry->obj);
585 if (relocate_objects(obj_main,
586 ld_bind_now != NULL && *ld_bind_now != '\0',
587 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
590 dbg("doing copy relocations");
591 if (do_copy_relocations(obj_main) == -1)
594 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
595 dump_relocations(obj_main);
600 * Setup TLS for main thread. This must be done after the
601 * relocations are processed, since tls initialization section
602 * might be the subject for relocations.
604 dbg("initializing initial thread local storage");
605 allocate_initial_tls(obj_list);
607 dbg("initializing key program variables");
608 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
609 set_program_var("environ", env);
610 set_program_var("__elf_aux_vector", aux);
612 /* Make a list of init functions to call. */
613 objlist_init(&initlist);
614 initlist_add_objects(obj_list, preload_tail, &initlist);
616 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
618 map_stacks_exec(NULL);
620 dbg("resolving ifuncs");
621 if (resolve_objects_ifunc(obj_main,
622 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
626 if (!obj_main->crt_no_init) {
628 * Make sure we don't call the main program's init and fini
629 * functions for binaries linked with old crt1 which calls
632 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
633 obj_main->preinit_array = obj_main->init_array =
634 obj_main->fini_array = (Elf_Addr)NULL;
637 wlock_acquire(rtld_bind_lock, &lockstate);
638 if (obj_main->crt_no_init)
640 objlist_call_init(&initlist, &lockstate);
641 _r_debug_postinit(&obj_main->linkmap);
642 objlist_clear(&initlist);
643 dbg("loading filtees");
644 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
645 if (ld_loadfltr || obj->z_loadfltr)
646 load_filtees(obj, 0, &lockstate);
648 lock_release(rtld_bind_lock, &lockstate);
650 dbg("transferring control to program entry point = %p", obj_main->entry);
652 /* Return the exit procedure and the program entry point. */
653 *exit_proc = rtld_exit;
655 return (func_ptr_type) obj_main->entry;
659 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
664 ptr = (void *)make_function_pointer(def, obj);
665 target = ((Elf_Addr (*)(void))ptr)();
666 return ((void *)target);
670 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
674 const Obj_Entry *defobj;
677 RtldLockState lockstate;
679 rlock_acquire(rtld_bind_lock, &lockstate);
680 if (sigsetjmp(lockstate.env, 0) != 0)
681 lock_upgrade(rtld_bind_lock, &lockstate);
683 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
685 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
687 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
688 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
692 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
693 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
695 target = (Elf_Addr)(defobj->relocbase + def->st_value);
697 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
698 defobj->strtab + def->st_name, basename(obj->path),
699 (void *)target, basename(defobj->path));
702 * Write the new contents for the jmpslot. Note that depending on
703 * architecture, the value which we need to return back to the
704 * lazy binding trampoline may or may not be the target
705 * address. The value returned from reloc_jmpslot() is the value
706 * that the trampoline needs.
708 target = reloc_jmpslot(where, target, defobj, obj, rel);
709 lock_release(rtld_bind_lock, &lockstate);
714 * Error reporting function. Use it like printf. If formats the message
715 * into a buffer, and sets things up so that the next call to dlerror()
716 * will return the message.
719 _rtld_error(const char *fmt, ...)
721 static char buf[512];
725 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
731 * Return a dynamically-allocated copy of the current error message, if any.
736 return error_message == NULL ? NULL : xstrdup(error_message);
740 * Restore the current error message from a copy which was previously saved
741 * by errmsg_save(). The copy is freed.
744 errmsg_restore(char *saved_msg)
746 if (saved_msg == NULL)
747 error_message = NULL;
749 _rtld_error("%s", saved_msg);
755 basename(const char *name)
757 const char *p = strrchr(name, '/');
758 return p != NULL ? p + 1 : name;
761 static struct utsname uts;
764 origin_subst_one(char *real, const char *kw, const char *subst,
767 char *p, *p1, *res, *resp;
768 int subst_len, kw_len, subst_count, old_len, new_len;
773 * First, count the number of the keyword occurences, to
774 * preallocate the final string.
776 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
783 * If the keyword is not found, just return.
785 if (subst_count == 0)
786 return (may_free ? real : xstrdup(real));
789 * There is indeed something to substitute. Calculate the
790 * length of the resulting string, and allocate it.
792 subst_len = strlen(subst);
793 old_len = strlen(real);
794 new_len = old_len + (subst_len - kw_len) * subst_count;
795 res = xmalloc(new_len + 1);
798 * Now, execute the substitution loop.
800 for (p = real, resp = res, *resp = '\0';;) {
803 /* Copy the prefix before keyword. */
804 memcpy(resp, p, p1 - p);
806 /* Keyword replacement. */
807 memcpy(resp, subst, subst_len);
815 /* Copy to the end of string and finish. */
823 origin_subst(char *real, const char *origin_path)
825 char *res1, *res2, *res3, *res4;
827 if (uts.sysname[0] == '\0') {
828 if (uname(&uts) != 0) {
829 _rtld_error("utsname failed: %d", errno);
833 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false);
834 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true);
835 res3 = origin_subst_one(res2, "$OSREL", uts.release, true);
836 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true);
843 const char *msg = dlerror();
847 rtld_fdputstr(STDERR_FILENO, msg);
848 rtld_fdputchar(STDERR_FILENO, '\n');
853 * Process a shared object's DYNAMIC section, and save the important
854 * information in its Obj_Entry structure.
857 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
858 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
861 Needed_Entry **needed_tail = &obj->needed;
862 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
863 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
864 const Elf_Hashelt *hashtab;
865 const Elf32_Word *hashval;
866 Elf32_Word bkt, nmaskwords;
869 int plttype = DT_REL;
875 obj->bind_now = false;
876 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
877 switch (dynp->d_tag) {
880 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
884 obj->relsize = dynp->d_un.d_val;
888 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
892 obj->pltrel = (const Elf_Rel *)
893 (obj->relocbase + dynp->d_un.d_ptr);
897 obj->pltrelsize = dynp->d_un.d_val;
901 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
905 obj->relasize = dynp->d_un.d_val;
909 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
913 plttype = dynp->d_un.d_val;
914 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
918 obj->symtab = (const Elf_Sym *)
919 (obj->relocbase + dynp->d_un.d_ptr);
923 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
927 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
931 obj->strsize = dynp->d_un.d_val;
935 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
940 obj->verneednum = dynp->d_un.d_val;
944 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
949 obj->verdefnum = dynp->d_un.d_val;
953 obj->versyms = (const Elf_Versym *)(obj->relocbase +
959 hashtab = (const Elf_Hashelt *)(obj->relocbase +
961 obj->nbuckets = hashtab[0];
962 obj->nchains = hashtab[1];
963 obj->buckets = hashtab + 2;
964 obj->chains = obj->buckets + obj->nbuckets;
965 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
966 obj->buckets != NULL;
972 hashtab = (const Elf_Hashelt *)(obj->relocbase +
974 obj->nbuckets_gnu = hashtab[0];
975 obj->symndx_gnu = hashtab[1];
976 nmaskwords = hashtab[2];
977 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
978 /* Number of bitmask words is required to be power of 2 */
979 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0);
980 obj->maskwords_bm_gnu = nmaskwords - 1;
981 obj->shift2_gnu = hashtab[3];
982 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
983 obj->buckets_gnu = hashtab + 4 + bloom_size32;
984 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
986 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 &&
987 obj->buckets_gnu != NULL;
993 Needed_Entry *nep = NEW(Needed_Entry);
994 nep->name = dynp->d_un.d_val;
999 needed_tail = &nep->next;
1005 Needed_Entry *nep = NEW(Needed_Entry);
1006 nep->name = dynp->d_un.d_val;
1010 *needed_filtees_tail = nep;
1011 needed_filtees_tail = &nep->next;
1017 Needed_Entry *nep = NEW(Needed_Entry);
1018 nep->name = dynp->d_un.d_val;
1022 *needed_aux_filtees_tail = nep;
1023 needed_aux_filtees_tail = &nep->next;
1028 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1032 obj->textrel = true;
1036 obj->symbolic = true;
1041 * We have to wait until later to process this, because we
1042 * might not have gotten the address of the string table yet.
1052 *dyn_runpath = dynp;
1056 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1059 case DT_PREINIT_ARRAY:
1060 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1063 case DT_PREINIT_ARRAYSZ:
1064 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1068 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1071 case DT_INIT_ARRAYSZ:
1072 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1076 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1080 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1083 case DT_FINI_ARRAYSZ:
1084 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1088 * Don't process DT_DEBUG on MIPS as the dynamic section
1089 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1094 /* XXX - not implemented yet */
1096 dbg("Filling in DT_DEBUG entry");
1097 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1102 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1103 obj->z_origin = true;
1104 if (dynp->d_un.d_val & DF_SYMBOLIC)
1105 obj->symbolic = true;
1106 if (dynp->d_un.d_val & DF_TEXTREL)
1107 obj->textrel = true;
1108 if (dynp->d_un.d_val & DF_BIND_NOW)
1109 obj->bind_now = true;
1110 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1114 case DT_MIPS_LOCAL_GOTNO:
1115 obj->local_gotno = dynp->d_un.d_val;
1118 case DT_MIPS_SYMTABNO:
1119 obj->symtabno = dynp->d_un.d_val;
1122 case DT_MIPS_GOTSYM:
1123 obj->gotsym = dynp->d_un.d_val;
1126 case DT_MIPS_RLD_MAP:
1129 dbg("Filling in DT_DEBUG entry");
1130 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1136 if (dynp->d_un.d_val & DF_1_NOOPEN)
1137 obj->z_noopen = true;
1138 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1139 obj->z_origin = true;
1140 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1142 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1143 obj->bind_now = true;
1144 if (dynp->d_un.d_val & DF_1_NODELETE)
1145 obj->z_nodelete = true;
1146 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1147 obj->z_loadfltr = true;
1148 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1149 obj->z_interpose = true;
1150 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1151 obj->z_nodeflib = true;
1156 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1163 obj->traced = false;
1165 if (plttype == DT_RELA) {
1166 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1168 obj->pltrelasize = obj->pltrelsize;
1169 obj->pltrelsize = 0;
1172 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1173 if (obj->valid_hash_sysv)
1174 obj->dynsymcount = obj->nchains;
1175 else if (obj->valid_hash_gnu) {
1176 obj->dynsymcount = 0;
1177 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1178 if (obj->buckets_gnu[bkt] == 0)
1180 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1183 while ((*hashval++ & 1u) == 0);
1185 obj->dynsymcount += obj->symndx_gnu;
1190 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1191 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1194 if (obj->z_origin && obj->origin_path == NULL) {
1195 obj->origin_path = xmalloc(PATH_MAX);
1196 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1200 if (dyn_runpath != NULL) {
1201 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1203 obj->runpath = origin_subst(obj->runpath, obj->origin_path);
1205 else if (dyn_rpath != NULL) {
1206 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1208 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1211 if (dyn_soname != NULL)
1212 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1216 digest_dynamic(Obj_Entry *obj, int early)
1218 const Elf_Dyn *dyn_rpath;
1219 const Elf_Dyn *dyn_soname;
1220 const Elf_Dyn *dyn_runpath;
1222 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1223 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1227 * Process a shared object's program header. This is used only for the
1228 * main program, when the kernel has already loaded the main program
1229 * into memory before calling the dynamic linker. It creates and
1230 * returns an Obj_Entry structure.
1233 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1236 const Elf_Phdr *phlimit = phdr + phnum;
1238 Elf_Addr note_start, note_end;
1242 for (ph = phdr; ph < phlimit; ph++) {
1243 if (ph->p_type != PT_PHDR)
1247 obj->phsize = ph->p_memsz;
1248 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1252 obj->stack_flags = PF_X | PF_R | PF_W;
1254 for (ph = phdr; ph < phlimit; ph++) {
1255 switch (ph->p_type) {
1258 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1262 if (nsegs == 0) { /* First load segment */
1263 obj->vaddrbase = trunc_page(ph->p_vaddr);
1264 obj->mapbase = obj->vaddrbase + obj->relocbase;
1265 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1267 } else { /* Last load segment */
1268 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1275 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1280 obj->tlssize = ph->p_memsz;
1281 obj->tlsalign = ph->p_align;
1282 obj->tlsinitsize = ph->p_filesz;
1283 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1287 obj->stack_flags = ph->p_flags;
1291 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1292 obj->relro_size = round_page(ph->p_memsz);
1296 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1297 note_end = note_start + ph->p_filesz;
1298 digest_notes(obj, note_start, note_end);
1303 _rtld_error("%s: too few PT_LOAD segments", path);
1312 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1314 const Elf_Note *note;
1315 const char *note_name;
1318 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1319 note = (const Elf_Note *)((const char *)(note + 1) +
1320 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1321 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1322 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1323 note->n_descsz != sizeof(int32_t))
1325 if (note->n_type != ABI_NOTETYPE &&
1326 note->n_type != CRT_NOINIT_NOTETYPE)
1328 note_name = (const char *)(note + 1);
1329 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1330 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1332 switch (note->n_type) {
1334 /* FreeBSD osrel note */
1335 p = (uintptr_t)(note + 1);
1336 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1337 obj->osrel = *(const int32_t *)(p);
1338 dbg("note osrel %d", obj->osrel);
1340 case CRT_NOINIT_NOTETYPE:
1341 /* FreeBSD 'crt does not call init' note */
1342 obj->crt_no_init = true;
1343 dbg("note crt_no_init");
1350 dlcheck(void *handle)
1354 for (obj = obj_list; obj != NULL; obj = obj->next)
1355 if (obj == (Obj_Entry *) handle)
1358 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1359 _rtld_error("Invalid shared object handle %p", handle);
1366 * If the given object is already in the donelist, return true. Otherwise
1367 * add the object to the list and return false.
1370 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1374 for (i = 0; i < dlp->num_used; i++)
1375 if (dlp->objs[i] == obj)
1378 * Our donelist allocation should always be sufficient. But if
1379 * our threads locking isn't working properly, more shared objects
1380 * could have been loaded since we allocated the list. That should
1381 * never happen, but we'll handle it properly just in case it does.
1383 if (dlp->num_used < dlp->num_alloc)
1384 dlp->objs[dlp->num_used++] = obj;
1389 * Hash function for symbol table lookup. Don't even think about changing
1390 * this. It is specified by the System V ABI.
1393 elf_hash(const char *name)
1395 const unsigned char *p = (const unsigned char *) name;
1396 unsigned long h = 0;
1399 while (*p != '\0') {
1400 h = (h << 4) + *p++;
1401 if ((g = h & 0xf0000000) != 0)
1409 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1410 * unsigned in case it's implemented with a wider type.
1413 gnu_hash(const char *s)
1419 for (c = *s; c != '\0'; c = *++s)
1421 return (h & 0xffffffff);
1425 * Find the library with the given name, and return its full pathname.
1426 * The returned string is dynamically allocated. Generates an error
1427 * message and returns NULL if the library cannot be found.
1429 * If the second argument is non-NULL, then it refers to an already-
1430 * loaded shared object, whose library search path will be searched.
1432 * The search order is:
1433 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1434 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1436 * DT_RUNPATH in the referencing file
1437 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1439 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1441 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1444 find_library(const char *xname, const Obj_Entry *refobj)
1448 bool nodeflib, objgiven;
1450 objgiven = refobj != NULL;
1451 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1452 if (xname[0] != '/' && !trust) {
1453 _rtld_error("Absolute pathname required for shared object \"%s\"",
1457 if (objgiven && refobj->z_origin) {
1458 return (origin_subst(__DECONST(char *, xname),
1459 refobj->origin_path));
1461 return (xstrdup(xname));
1465 if (libmap_disable || !objgiven ||
1466 (name = lm_find(refobj->path, xname)) == NULL)
1467 name = (char *)xname;
1469 dbg(" Searching for \"%s\"", name);
1472 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1473 * back to pre-conforming behaviour if user requested so with
1474 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1477 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1478 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1480 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1481 (pathname = search_library_path(name, gethints(false))) != NULL ||
1482 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1485 nodeflib = objgiven ? refobj->z_nodeflib : false;
1487 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1488 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1489 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1490 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1492 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1493 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1494 (objgiven && !nodeflib &&
1495 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1499 if (objgiven && refobj->path != NULL) {
1500 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1501 name, basename(refobj->path));
1503 _rtld_error("Shared object \"%s\" not found", name);
1509 * Given a symbol number in a referencing object, find the corresponding
1510 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1511 * no definition was found. Returns a pointer to the Obj_Entry of the
1512 * defining object via the reference parameter DEFOBJ_OUT.
1515 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1516 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1517 RtldLockState *lockstate)
1521 const Obj_Entry *defobj;
1527 * If we have already found this symbol, get the information from
1530 if (symnum >= refobj->dynsymcount)
1531 return NULL; /* Bad object */
1532 if (cache != NULL && cache[symnum].sym != NULL) {
1533 *defobj_out = cache[symnum].obj;
1534 return cache[symnum].sym;
1537 ref = refobj->symtab + symnum;
1538 name = refobj->strtab + ref->st_name;
1543 * We don't have to do a full scale lookup if the symbol is local.
1544 * We know it will bind to the instance in this load module; to
1545 * which we already have a pointer (ie ref). By not doing a lookup,
1546 * we not only improve performance, but it also avoids unresolvable
1547 * symbols when local symbols are not in the hash table. This has
1548 * been seen with the ia64 toolchain.
1550 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1551 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1552 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1555 symlook_init(&req, name);
1557 req.ventry = fetch_ventry(refobj, symnum);
1558 req.lockstate = lockstate;
1559 res = symlook_default(&req, refobj);
1562 defobj = req.defobj_out;
1570 * If we found no definition and the reference is weak, treat the
1571 * symbol as having the value zero.
1573 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1579 *defobj_out = defobj;
1580 /* Record the information in the cache to avoid subsequent lookups. */
1581 if (cache != NULL) {
1582 cache[symnum].sym = def;
1583 cache[symnum].obj = defobj;
1586 if (refobj != &obj_rtld)
1587 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1593 * Return the search path from the ldconfig hints file, reading it if
1594 * necessary. If nostdlib is true, then the default search paths are
1595 * not added to result.
1597 * Returns NULL if there are problems with the hints file,
1598 * or if the search path there is empty.
1601 gethints(bool nostdlib)
1603 static char *hints, *filtered_path;
1604 struct elfhints_hdr hdr;
1605 struct fill_search_info_args sargs, hargs;
1606 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1607 struct dl_serpath *SLPpath, *hintpath;
1609 unsigned int SLPndx, hintndx, fndx, fcount;
1614 /* First call, read the hints file */
1615 if (hints == NULL) {
1616 /* Keep from trying again in case the hints file is bad. */
1619 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1)
1621 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1622 hdr.magic != ELFHINTS_MAGIC ||
1627 p = xmalloc(hdr.dirlistlen + 1);
1628 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1629 read(fd, p, hdr.dirlistlen + 1) !=
1630 (ssize_t)hdr.dirlistlen + 1) {
1640 * If caller agreed to receive list which includes the default
1641 * paths, we are done. Otherwise, if we still did not
1642 * calculated filtered result, do it now.
1645 return (hints[0] != '\0' ? hints : NULL);
1646 if (filtered_path != NULL)
1650 * Obtain the list of all configured search paths, and the
1651 * list of the default paths.
1653 * First estimate the size of the results.
1655 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1657 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1660 sargs.request = RTLD_DI_SERINFOSIZE;
1661 sargs.serinfo = &smeta;
1662 hargs.request = RTLD_DI_SERINFOSIZE;
1663 hargs.serinfo = &hmeta;
1665 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1666 path_enumerate(p, fill_search_info, &hargs);
1668 SLPinfo = xmalloc(smeta.dls_size);
1669 hintinfo = xmalloc(hmeta.dls_size);
1672 * Next fetch both sets of paths.
1674 sargs.request = RTLD_DI_SERINFO;
1675 sargs.serinfo = SLPinfo;
1676 sargs.serpath = &SLPinfo->dls_serpath[0];
1677 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1679 hargs.request = RTLD_DI_SERINFO;
1680 hargs.serinfo = hintinfo;
1681 hargs.serpath = &hintinfo->dls_serpath[0];
1682 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1684 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1685 path_enumerate(p, fill_search_info, &hargs);
1688 * Now calculate the difference between two sets, by excluding
1689 * standard paths from the full set.
1693 filtered_path = xmalloc(hdr.dirlistlen + 1);
1694 hintpath = &hintinfo->dls_serpath[0];
1695 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1697 SLPpath = &SLPinfo->dls_serpath[0];
1699 * Check each standard path against current.
1701 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1702 /* matched, skip the path */
1703 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1711 * Not matched against any standard path, add the path
1712 * to result. Separate consequtive paths with ':'.
1715 filtered_path[fndx] = ':';
1719 flen = strlen(hintpath->dls_name);
1720 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1723 filtered_path[fndx] = '\0';
1729 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1733 init_dag(Obj_Entry *root)
1735 const Needed_Entry *needed;
1736 const Objlist_Entry *elm;
1739 if (root->dag_inited)
1741 donelist_init(&donelist);
1743 /* Root object belongs to own DAG. */
1744 objlist_push_tail(&root->dldags, root);
1745 objlist_push_tail(&root->dagmembers, root);
1746 donelist_check(&donelist, root);
1749 * Add dependencies of root object to DAG in breadth order
1750 * by exploiting the fact that each new object get added
1751 * to the tail of the dagmembers list.
1753 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1754 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1755 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1757 objlist_push_tail(&needed->obj->dldags, root);
1758 objlist_push_tail(&root->dagmembers, needed->obj);
1761 root->dag_inited = true;
1765 process_nodelete(Obj_Entry *root)
1767 const Objlist_Entry *elm;
1770 * Walk over object DAG and process every dependent object that
1771 * is marked as DF_1_NODELETE. They need to grow their own DAG,
1772 * which then should have its reference upped separately.
1774 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1775 if (elm->obj != NULL && elm->obj->z_nodelete &&
1776 !elm->obj->ref_nodel) {
1777 dbg("obj %s nodelete", elm->obj->path);
1780 elm->obj->ref_nodel = true;
1785 * Initialize the dynamic linker. The argument is the address at which
1786 * the dynamic linker has been mapped into memory. The primary task of
1787 * this function is to relocate the dynamic linker.
1790 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1792 Obj_Entry objtmp; /* Temporary rtld object */
1793 const Elf_Dyn *dyn_rpath;
1794 const Elf_Dyn *dyn_soname;
1795 const Elf_Dyn *dyn_runpath;
1798 * Conjure up an Obj_Entry structure for the dynamic linker.
1800 * The "path" member can't be initialized yet because string constants
1801 * cannot yet be accessed. Below we will set it correctly.
1803 memset(&objtmp, 0, sizeof(objtmp));
1806 objtmp.mapbase = mapbase;
1808 objtmp.relocbase = mapbase;
1810 if (RTLD_IS_DYNAMIC()) {
1811 objtmp.dynamic = rtld_dynamic(&objtmp);
1812 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1813 assert(objtmp.needed == NULL);
1814 #if !defined(__mips__)
1815 /* MIPS has a bogus DT_TEXTREL. */
1816 assert(!objtmp.textrel);
1820 * Temporarily put the dynamic linker entry into the object list, so
1821 * that symbols can be found.
1824 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1827 /* Initialize the object list. */
1828 obj_tail = &obj_list;
1830 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1831 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1833 if (aux_info[AT_PAGESZ] != NULL)
1834 pagesize = aux_info[AT_PAGESZ]->a_un.a_val;
1835 if (aux_info[AT_OSRELDATE] != NULL)
1836 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1838 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1840 /* Replace the path with a dynamically allocated copy. */
1841 obj_rtld.path = xstrdup(PATH_RTLD);
1843 r_debug.r_brk = r_debug_state;
1844 r_debug.r_state = RT_CONSISTENT;
1848 * Add the init functions from a needed object list (and its recursive
1849 * needed objects) to "list". This is not used directly; it is a helper
1850 * function for initlist_add_objects(). The write lock must be held
1851 * when this function is called.
1854 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1856 /* Recursively process the successor needed objects. */
1857 if (needed->next != NULL)
1858 initlist_add_neededs(needed->next, list);
1860 /* Process the current needed object. */
1861 if (needed->obj != NULL)
1862 initlist_add_objects(needed->obj, &needed->obj->next, list);
1866 * Scan all of the DAGs rooted in the range of objects from "obj" to
1867 * "tail" and add their init functions to "list". This recurses over
1868 * the DAGs and ensure the proper init ordering such that each object's
1869 * needed libraries are initialized before the object itself. At the
1870 * same time, this function adds the objects to the global finalization
1871 * list "list_fini" in the opposite order. The write lock must be
1872 * held when this function is called.
1875 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1878 if (obj->init_scanned || obj->init_done)
1880 obj->init_scanned = true;
1882 /* Recursively process the successor objects. */
1883 if (&obj->next != tail)
1884 initlist_add_objects(obj->next, tail, list);
1886 /* Recursively process the needed objects. */
1887 if (obj->needed != NULL)
1888 initlist_add_neededs(obj->needed, list);
1889 if (obj->needed_filtees != NULL)
1890 initlist_add_neededs(obj->needed_filtees, list);
1891 if (obj->needed_aux_filtees != NULL)
1892 initlist_add_neededs(obj->needed_aux_filtees, list);
1894 /* Add the object to the init list. */
1895 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1896 obj->init_array != (Elf_Addr)NULL)
1897 objlist_push_tail(list, obj);
1899 /* Add the object to the global fini list in the reverse order. */
1900 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1901 && !obj->on_fini_list) {
1902 objlist_push_head(&list_fini, obj);
1903 obj->on_fini_list = true;
1908 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1912 free_needed_filtees(Needed_Entry *n)
1914 Needed_Entry *needed, *needed1;
1916 for (needed = n; needed != NULL; needed = needed->next) {
1917 if (needed->obj != NULL) {
1918 dlclose(needed->obj);
1922 for (needed = n; needed != NULL; needed = needed1) {
1923 needed1 = needed->next;
1929 unload_filtees(Obj_Entry *obj)
1932 free_needed_filtees(obj->needed_filtees);
1933 obj->needed_filtees = NULL;
1934 free_needed_filtees(obj->needed_aux_filtees);
1935 obj->needed_aux_filtees = NULL;
1936 obj->filtees_loaded = false;
1940 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
1941 RtldLockState *lockstate)
1944 for (; needed != NULL; needed = needed->next) {
1945 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
1946 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
1947 RTLD_LOCAL, lockstate);
1952 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
1955 lock_restart_for_upgrade(lockstate);
1956 if (!obj->filtees_loaded) {
1957 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
1958 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
1959 obj->filtees_loaded = true;
1964 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
1968 for (; needed != NULL; needed = needed->next) {
1969 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
1970 flags & ~RTLD_LO_NOLOAD);
1971 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
1978 * Given a shared object, traverse its list of needed objects, and load
1979 * each of them. Returns 0 on success. Generates an error message and
1980 * returns -1 on failure.
1983 load_needed_objects(Obj_Entry *first, int flags)
1987 for (obj = first; obj != NULL; obj = obj->next) {
1988 if (process_needed(obj, obj->needed, flags) == -1)
1995 load_preload_objects(void)
1997 char *p = ld_preload;
1999 static const char delim[] = " \t:;";
2004 p += strspn(p, delim);
2005 while (*p != '\0') {
2006 size_t len = strcspn(p, delim);
2011 obj = load_object(p, -1, NULL, 0);
2013 return -1; /* XXX - cleanup */
2014 obj->z_interpose = true;
2017 p += strspn(p, delim);
2019 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2024 printable_path(const char *path)
2027 return (path == NULL ? "<unknown>" : path);
2031 * Load a shared object into memory, if it is not already loaded. The
2032 * object may be specified by name or by user-supplied file descriptor
2033 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2036 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2040 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2048 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2049 if (object_match_name(obj, name))
2053 path = find_library(name, refobj);
2060 * If we didn't find a match by pathname, or the name is not
2061 * supplied, open the file and check again by device and inode.
2062 * This avoids false mismatches caused by multiple links or ".."
2065 * To avoid a race, we open the file and use fstat() rather than
2070 if ((fd = open(path, O_RDONLY)) == -1) {
2071 _rtld_error("Cannot open \"%s\"", path);
2078 _rtld_error("Cannot dup fd");
2083 if (fstat(fd, &sb) == -1) {
2084 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2089 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2090 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2092 if (obj != NULL && name != NULL) {
2093 object_add_name(obj, name);
2098 if (flags & RTLD_LO_NOLOAD) {
2104 /* First use of this object, so we must map it in */
2105 obj = do_load_object(fd, name, path, &sb, flags);
2114 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2121 * but first, make sure that environment variables haven't been
2122 * used to circumvent the noexec flag on a filesystem.
2124 if (dangerous_ld_env) {
2125 if (fstatfs(fd, &fs) != 0) {
2126 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2129 if (fs.f_flags & MNT_NOEXEC) {
2130 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2134 dbg("loading \"%s\"", printable_path(path));
2135 obj = map_object(fd, printable_path(path), sbp);
2140 * If DT_SONAME is present in the object, digest_dynamic2 already
2141 * added it to the object names.
2144 object_add_name(obj, name);
2146 digest_dynamic(obj, 0);
2147 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2148 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2149 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2151 dbg("refusing to load non-loadable \"%s\"", obj->path);
2152 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2153 munmap(obj->mapbase, obj->mapsize);
2159 obj_tail = &obj->next;
2162 linkmap_add(obj); /* for GDB & dlinfo() */
2163 max_stack_flags |= obj->stack_flags;
2165 dbg(" %p .. %p: %s", obj->mapbase,
2166 obj->mapbase + obj->mapsize - 1, obj->path);
2168 dbg(" WARNING: %s has impure text", obj->path);
2169 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2176 obj_from_addr(const void *addr)
2180 for (obj = obj_list; obj != NULL; obj = obj->next) {
2181 if (addr < (void *) obj->mapbase)
2183 if (addr < (void *) (obj->mapbase + obj->mapsize))
2192 Elf_Addr *preinit_addr;
2195 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2196 if (preinit_addr == NULL)
2199 for (index = 0; index < obj_main->preinit_array_num; index++) {
2200 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2201 dbg("calling preinit function for %s at %p", obj_main->path,
2202 (void *)preinit_addr[index]);
2203 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2204 0, 0, obj_main->path);
2205 call_init_pointer(obj_main, preinit_addr[index]);
2211 * Call the finalization functions for each of the objects in "list"
2212 * belonging to the DAG of "root" and referenced once. If NULL "root"
2213 * is specified, every finalization function will be called regardless
2214 * of the reference count and the list elements won't be freed. All of
2215 * the objects are expected to have non-NULL fini functions.
2218 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2222 Elf_Addr *fini_addr;
2225 assert(root == NULL || root->refcount == 1);
2228 * Preserve the current error message since a fini function might
2229 * call into the dynamic linker and overwrite it.
2231 saved_msg = errmsg_save();
2233 STAILQ_FOREACH(elm, list, link) {
2234 if (root != NULL && (elm->obj->refcount != 1 ||
2235 objlist_find(&root->dagmembers, elm->obj) == NULL))
2237 /* Remove object from fini list to prevent recursive invocation. */
2238 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2240 * XXX: If a dlopen() call references an object while the
2241 * fini function is in progress, we might end up trying to
2242 * unload the referenced object in dlclose() or the object
2243 * won't be unloaded although its fini function has been
2246 lock_release(rtld_bind_lock, lockstate);
2249 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2250 * When this happens, DT_FINI_ARRAY is processed first.
2252 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2253 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2254 for (index = elm->obj->fini_array_num - 1; index >= 0;
2256 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2257 dbg("calling fini function for %s at %p",
2258 elm->obj->path, (void *)fini_addr[index]);
2259 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2260 (void *)fini_addr[index], 0, 0, elm->obj->path);
2261 call_initfini_pointer(elm->obj, fini_addr[index]);
2265 if (elm->obj->fini != (Elf_Addr)NULL) {
2266 dbg("calling fini function for %s at %p", elm->obj->path,
2267 (void *)elm->obj->fini);
2268 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2269 0, 0, elm->obj->path);
2270 call_initfini_pointer(elm->obj, elm->obj->fini);
2272 wlock_acquire(rtld_bind_lock, lockstate);
2273 /* No need to free anything if process is going down. */
2277 * We must restart the list traversal after every fini call
2278 * because a dlclose() call from the fini function or from
2279 * another thread might have modified the reference counts.
2283 } while (elm != NULL);
2284 errmsg_restore(saved_msg);
2288 * Call the initialization functions for each of the objects in
2289 * "list". All of the objects are expected to have non-NULL init
2293 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2298 Elf_Addr *init_addr;
2302 * Clean init_scanned flag so that objects can be rechecked and
2303 * possibly initialized earlier if any of vectors called below
2304 * cause the change by using dlopen.
2306 for (obj = obj_list; obj != NULL; obj = obj->next)
2307 obj->init_scanned = false;
2310 * Preserve the current error message since an init function might
2311 * call into the dynamic linker and overwrite it.
2313 saved_msg = errmsg_save();
2314 STAILQ_FOREACH(elm, list, link) {
2315 if (elm->obj->init_done) /* Initialized early. */
2318 * Race: other thread might try to use this object before current
2319 * one completes the initilization. Not much can be done here
2320 * without better locking.
2322 elm->obj->init_done = true;
2323 lock_release(rtld_bind_lock, lockstate);
2326 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2327 * When this happens, DT_INIT is processed first.
2329 if (elm->obj->init != (Elf_Addr)NULL) {
2330 dbg("calling init function for %s at %p", elm->obj->path,
2331 (void *)elm->obj->init);
2332 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2333 0, 0, elm->obj->path);
2334 call_initfini_pointer(elm->obj, elm->obj->init);
2336 init_addr = (Elf_Addr *)elm->obj->init_array;
2337 if (init_addr != NULL) {
2338 for (index = 0; index < elm->obj->init_array_num; index++) {
2339 if (init_addr[index] != 0 && init_addr[index] != 1) {
2340 dbg("calling init function for %s at %p", elm->obj->path,
2341 (void *)init_addr[index]);
2342 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2343 (void *)init_addr[index], 0, 0, elm->obj->path);
2344 call_init_pointer(elm->obj, init_addr[index]);
2348 wlock_acquire(rtld_bind_lock, lockstate);
2350 errmsg_restore(saved_msg);
2354 objlist_clear(Objlist *list)
2358 while (!STAILQ_EMPTY(list)) {
2359 elm = STAILQ_FIRST(list);
2360 STAILQ_REMOVE_HEAD(list, link);
2365 static Objlist_Entry *
2366 objlist_find(Objlist *list, const Obj_Entry *obj)
2370 STAILQ_FOREACH(elm, list, link)
2371 if (elm->obj == obj)
2377 objlist_init(Objlist *list)
2383 objlist_push_head(Objlist *list, Obj_Entry *obj)
2387 elm = NEW(Objlist_Entry);
2389 STAILQ_INSERT_HEAD(list, elm, link);
2393 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2397 elm = NEW(Objlist_Entry);
2399 STAILQ_INSERT_TAIL(list, elm, link);
2403 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2405 Objlist_Entry *elm, *listelm;
2407 STAILQ_FOREACH(listelm, list, link) {
2408 if (listelm->obj == listobj)
2411 elm = NEW(Objlist_Entry);
2413 if (listelm != NULL)
2414 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2416 STAILQ_INSERT_TAIL(list, elm, link);
2420 objlist_remove(Objlist *list, Obj_Entry *obj)
2424 if ((elm = objlist_find(list, obj)) != NULL) {
2425 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2431 * Relocate dag rooted in the specified object.
2432 * Returns 0 on success, or -1 on failure.
2436 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2437 int flags, RtldLockState *lockstate)
2443 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2444 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2453 * Relocate single object.
2454 * Returns 0 on success, or -1 on failure.
2457 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2458 int flags, RtldLockState *lockstate)
2463 obj->relocated = true;
2465 dbg("relocating \"%s\"", obj->path);
2467 if (obj->symtab == NULL || obj->strtab == NULL ||
2468 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2469 _rtld_error("%s: Shared object has no run-time symbol table",
2475 /* There are relocations to the write-protected text segment. */
2476 if (mprotect(obj->mapbase, obj->textsize,
2477 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2478 _rtld_error("%s: Cannot write-enable text segment: %s",
2479 obj->path, rtld_strerror(errno));
2484 /* Process the non-PLT relocations. */
2485 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2488 if (obj->textrel) { /* Re-protected the text segment. */
2489 if (mprotect(obj->mapbase, obj->textsize,
2490 PROT_READ|PROT_EXEC) == -1) {
2491 _rtld_error("%s: Cannot write-protect text segment: %s",
2492 obj->path, rtld_strerror(errno));
2498 /* Set the special PLT or GOT entries. */
2501 /* Process the PLT relocations. */
2502 if (reloc_plt(obj) == -1)
2504 /* Relocate the jump slots if we are doing immediate binding. */
2505 if (obj->bind_now || bind_now)
2506 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2509 if (obj->relro_size > 0) {
2510 if (mprotect(obj->relro_page, obj->relro_size,
2512 _rtld_error("%s: Cannot enforce relro protection: %s",
2513 obj->path, rtld_strerror(errno));
2519 * Set up the magic number and version in the Obj_Entry. These
2520 * were checked in the crt1.o from the original ElfKit, so we
2521 * set them for backward compatibility.
2523 obj->magic = RTLD_MAGIC;
2524 obj->version = RTLD_VERSION;
2530 * Relocate newly-loaded shared objects. The argument is a pointer to
2531 * the Obj_Entry for the first such object. All objects from the first
2532 * to the end of the list of objects are relocated. Returns 0 on success,
2536 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2537 int flags, RtldLockState *lockstate)
2542 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2543 error = relocate_object(obj, bind_now, rtldobj, flags,
2552 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2553 * referencing STT_GNU_IFUNC symbols is postponed till the other
2554 * relocations are done. The indirect functions specified as
2555 * ifunc are allowed to call other symbols, so we need to have
2556 * objects relocated before asking for resolution from indirects.
2558 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2559 * instead of the usual lazy handling of PLT slots. It is
2560 * consistent with how GNU does it.
2563 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2564 RtldLockState *lockstate)
2566 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2568 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2569 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2575 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2576 RtldLockState *lockstate)
2580 for (obj = first; obj != NULL; obj = obj->next) {
2581 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2588 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2589 RtldLockState *lockstate)
2593 STAILQ_FOREACH(elm, list, link) {
2594 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2602 * Cleanup procedure. It will be called (by the atexit mechanism) just
2603 * before the process exits.
2608 RtldLockState lockstate;
2610 wlock_acquire(rtld_bind_lock, &lockstate);
2612 objlist_call_fini(&list_fini, NULL, &lockstate);
2613 /* No need to remove the items from the list, since we are exiting. */
2614 if (!libmap_disable)
2616 lock_release(rtld_bind_lock, &lockstate);
2620 * Iterate over a search path, translate each element, and invoke the
2621 * callback on the result.
2624 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2630 path += strspn(path, ":;");
2631 while (*path != '\0') {
2635 len = strcspn(path, ":;");
2636 trans = lm_findn(NULL, path, len);
2638 res = callback(trans, strlen(trans), arg);
2640 res = callback(path, len, arg);
2646 path += strspn(path, ":;");
2652 struct try_library_args {
2660 try_library_path(const char *dir, size_t dirlen, void *param)
2662 struct try_library_args *arg;
2665 if (*dir == '/' || trust) {
2668 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2671 pathname = arg->buffer;
2672 strncpy(pathname, dir, dirlen);
2673 pathname[dirlen] = '/';
2674 strcpy(pathname + dirlen + 1, arg->name);
2676 dbg(" Trying \"%s\"", pathname);
2677 if (access(pathname, F_OK) == 0) { /* We found it */
2678 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2679 strcpy(pathname, arg->buffer);
2687 search_library_path(const char *name, const char *path)
2690 struct try_library_args arg;
2696 arg.namelen = strlen(name);
2697 arg.buffer = xmalloc(PATH_MAX);
2698 arg.buflen = PATH_MAX;
2700 p = path_enumerate(path, try_library_path, &arg);
2708 dlclose(void *handle)
2711 RtldLockState lockstate;
2713 wlock_acquire(rtld_bind_lock, &lockstate);
2714 root = dlcheck(handle);
2716 lock_release(rtld_bind_lock, &lockstate);
2719 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2722 /* Unreference the object and its dependencies. */
2723 root->dl_refcount--;
2725 if (root->refcount == 1) {
2727 * The object will be no longer referenced, so we must unload it.
2728 * First, call the fini functions.
2730 objlist_call_fini(&list_fini, root, &lockstate);
2734 /* Finish cleaning up the newly-unreferenced objects. */
2735 GDB_STATE(RT_DELETE,&root->linkmap);
2736 unload_object(root);
2737 GDB_STATE(RT_CONSISTENT,NULL);
2741 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2742 lock_release(rtld_bind_lock, &lockstate);
2749 char *msg = error_message;
2750 error_message = NULL;
2755 * This function is deprecated and has no effect.
2758 dllockinit(void *context,
2759 void *(*lock_create)(void *context),
2760 void (*rlock_acquire)(void *lock),
2761 void (*wlock_acquire)(void *lock),
2762 void (*lock_release)(void *lock),
2763 void (*lock_destroy)(void *lock),
2764 void (*context_destroy)(void *context))
2766 static void *cur_context;
2767 static void (*cur_context_destroy)(void *);
2769 /* Just destroy the context from the previous call, if necessary. */
2770 if (cur_context_destroy != NULL)
2771 cur_context_destroy(cur_context);
2772 cur_context = context;
2773 cur_context_destroy = context_destroy;
2777 dlopen(const char *name, int mode)
2780 return (rtld_dlopen(name, -1, mode));
2784 fdlopen(int fd, int mode)
2787 return (rtld_dlopen(NULL, fd, mode));
2791 rtld_dlopen(const char *name, int fd, int mode)
2793 RtldLockState lockstate;
2796 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2797 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2798 if (ld_tracing != NULL) {
2799 rlock_acquire(rtld_bind_lock, &lockstate);
2800 if (sigsetjmp(lockstate.env, 0) != 0)
2801 lock_upgrade(rtld_bind_lock, &lockstate);
2802 environ = (char **)*get_program_var_addr("environ", &lockstate);
2803 lock_release(rtld_bind_lock, &lockstate);
2805 lo_flags = RTLD_LO_DLOPEN;
2806 if (mode & RTLD_NODELETE)
2807 lo_flags |= RTLD_LO_NODELETE;
2808 if (mode & RTLD_NOLOAD)
2809 lo_flags |= RTLD_LO_NOLOAD;
2810 if (ld_tracing != NULL)
2811 lo_flags |= RTLD_LO_TRACE;
2813 return (dlopen_object(name, fd, obj_main, lo_flags,
2814 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
2818 dlopen_cleanup(Obj_Entry *obj)
2823 if (obj->refcount == 0)
2828 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2829 int mode, RtldLockState *lockstate)
2831 Obj_Entry **old_obj_tail;
2834 RtldLockState mlockstate;
2837 objlist_init(&initlist);
2839 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
2840 wlock_acquire(rtld_bind_lock, &mlockstate);
2841 lockstate = &mlockstate;
2843 GDB_STATE(RT_ADD,NULL);
2845 old_obj_tail = obj_tail;
2847 if (name == NULL && fd == -1) {
2851 obj = load_object(name, fd, refobj, lo_flags);
2856 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2857 objlist_push_tail(&list_global, obj);
2858 if (*old_obj_tail != NULL) { /* We loaded something new. */
2859 assert(*old_obj_tail == obj);
2860 result = load_needed_objects(obj,
2861 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
2865 result = rtld_verify_versions(&obj->dagmembers);
2866 if (result != -1 && ld_tracing)
2868 if (result == -1 || relocate_object_dag(obj,
2869 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
2870 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2872 dlopen_cleanup(obj);
2874 } else if (lo_flags & RTLD_LO_EARLY) {
2876 * Do not call the init functions for early loaded
2877 * filtees. The image is still not initialized enough
2880 * Our object is found by the global object list and
2881 * will be ordered among all init calls done right
2882 * before transferring control to main.
2885 /* Make list of init functions to call. */
2886 initlist_add_objects(obj, &obj->next, &initlist);
2889 * Process all no_delete objects here, given them own
2890 * DAGs to prevent their dependencies from being unloaded.
2891 * This has to be done after we have loaded all of the
2892 * dependencies, so that we do not miss any.
2895 process_nodelete(obj);
2898 * Bump the reference counts for objects on this DAG. If
2899 * this is the first dlopen() call for the object that was
2900 * already loaded as a dependency, initialize the dag
2906 if ((lo_flags & RTLD_LO_TRACE) != 0)
2909 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2910 obj->z_nodelete) && !obj->ref_nodel) {
2911 dbg("obj %s nodelete", obj->path);
2913 obj->z_nodelete = obj->ref_nodel = true;
2917 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2919 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2921 if (!(lo_flags & RTLD_LO_EARLY)) {
2922 map_stacks_exec(lockstate);
2925 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
2926 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2928 objlist_clear(&initlist);
2929 dlopen_cleanup(obj);
2930 if (lockstate == &mlockstate)
2931 lock_release(rtld_bind_lock, lockstate);
2935 if (!(lo_flags & RTLD_LO_EARLY)) {
2936 /* Call the init functions. */
2937 objlist_call_init(&initlist, lockstate);
2939 objlist_clear(&initlist);
2940 if (lockstate == &mlockstate)
2941 lock_release(rtld_bind_lock, lockstate);
2944 trace_loaded_objects(obj);
2945 if (lockstate == &mlockstate)
2946 lock_release(rtld_bind_lock, lockstate);
2951 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
2955 const Obj_Entry *obj, *defobj;
2958 RtldLockState lockstate;
2967 symlook_init(&req, name);
2969 req.flags = flags | SYMLOOK_IN_PLT;
2970 req.lockstate = &lockstate;
2972 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
2973 rlock_acquire(rtld_bind_lock, &lockstate);
2974 if (sigsetjmp(lockstate.env, 0) != 0)
2975 lock_upgrade(rtld_bind_lock, &lockstate);
2976 if (handle == NULL || handle == RTLD_NEXT ||
2977 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
2979 if ((obj = obj_from_addr(retaddr)) == NULL) {
2980 _rtld_error("Cannot determine caller's shared object");
2981 lock_release(rtld_bind_lock, &lockstate);
2982 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
2985 if (handle == NULL) { /* Just the caller's shared object. */
2986 res = symlook_obj(&req, obj);
2989 defobj = req.defobj_out;
2991 } else if (handle == RTLD_NEXT || /* Objects after caller's */
2992 handle == RTLD_SELF) { /* ... caller included */
2993 if (handle == RTLD_NEXT)
2995 for (; obj != NULL; obj = obj->next) {
2996 res = symlook_obj(&req, obj);
2999 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3001 defobj = req.defobj_out;
3002 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3008 * Search the dynamic linker itself, and possibly resolve the
3009 * symbol from there. This is how the application links to
3010 * dynamic linker services such as dlopen.
3012 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3013 res = symlook_obj(&req, &obj_rtld);
3016 defobj = req.defobj_out;
3020 assert(handle == RTLD_DEFAULT);
3021 res = symlook_default(&req, obj);
3023 defobj = req.defobj_out;
3028 if ((obj = dlcheck(handle)) == NULL) {
3029 lock_release(rtld_bind_lock, &lockstate);
3030 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3034 donelist_init(&donelist);
3035 if (obj->mainprog) {
3036 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3037 res = symlook_global(&req, &donelist);
3040 defobj = req.defobj_out;
3043 * Search the dynamic linker itself, and possibly resolve the
3044 * symbol from there. This is how the application links to
3045 * dynamic linker services such as dlopen.
3047 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3048 res = symlook_obj(&req, &obj_rtld);
3051 defobj = req.defobj_out;
3056 /* Search the whole DAG rooted at the given object. */
3057 res = symlook_list(&req, &obj->dagmembers, &donelist);
3060 defobj = req.defobj_out;
3066 lock_release(rtld_bind_lock, &lockstate);
3069 * The value required by the caller is derived from the value
3070 * of the symbol. For the ia64 architecture, we need to
3071 * construct a function descriptor which the caller can use to
3072 * call the function with the right 'gp' value. For other
3073 * architectures and for non-functions, the value is simply
3074 * the relocated value of the symbol.
3076 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3077 sym = make_function_pointer(def, defobj);
3078 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3079 sym = rtld_resolve_ifunc(defobj, def);
3080 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3082 return (__tls_get_addr(defobj->tlsindex, def->st_value));
3084 ti.ti_module = defobj->tlsindex;
3085 ti.ti_offset = def->st_value;
3086 sym = __tls_get_addr(&ti);
3089 sym = defobj->relocbase + def->st_value;
3090 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3094 _rtld_error("Undefined symbol \"%s\"", name);
3095 lock_release(rtld_bind_lock, &lockstate);
3096 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3101 dlsym(void *handle, const char *name)
3103 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3108 dlfunc(void *handle, const char *name)
3115 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3121 dlvsym(void *handle, const char *name, const char *version)
3125 ventry.name = version;
3127 ventry.hash = elf_hash(version);
3129 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3134 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3136 const Obj_Entry *obj;
3137 RtldLockState lockstate;
3139 rlock_acquire(rtld_bind_lock, &lockstate);
3140 obj = obj_from_addr(addr);
3142 _rtld_error("No shared object contains address");
3143 lock_release(rtld_bind_lock, &lockstate);
3146 rtld_fill_dl_phdr_info(obj, phdr_info);
3147 lock_release(rtld_bind_lock, &lockstate);
3152 dladdr(const void *addr, Dl_info *info)
3154 const Obj_Entry *obj;
3157 unsigned long symoffset;
3158 RtldLockState lockstate;
3160 rlock_acquire(rtld_bind_lock, &lockstate);
3161 obj = obj_from_addr(addr);
3163 _rtld_error("No shared object contains address");
3164 lock_release(rtld_bind_lock, &lockstate);
3167 info->dli_fname = obj->path;
3168 info->dli_fbase = obj->mapbase;
3169 info->dli_saddr = (void *)0;
3170 info->dli_sname = NULL;
3173 * Walk the symbol list looking for the symbol whose address is
3174 * closest to the address sent in.
3176 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3177 def = obj->symtab + symoffset;
3180 * For skip the symbol if st_shndx is either SHN_UNDEF or
3183 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3187 * If the symbol is greater than the specified address, or if it
3188 * is further away from addr than the current nearest symbol,
3191 symbol_addr = obj->relocbase + def->st_value;
3192 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3195 /* Update our idea of the nearest symbol. */
3196 info->dli_sname = obj->strtab + def->st_name;
3197 info->dli_saddr = symbol_addr;
3200 if (info->dli_saddr == addr)
3203 lock_release(rtld_bind_lock, &lockstate);
3208 dlinfo(void *handle, int request, void *p)
3210 const Obj_Entry *obj;
3211 RtldLockState lockstate;
3214 rlock_acquire(rtld_bind_lock, &lockstate);
3216 if (handle == NULL || handle == RTLD_SELF) {
3219 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3220 if ((obj = obj_from_addr(retaddr)) == NULL)
3221 _rtld_error("Cannot determine caller's shared object");
3223 obj = dlcheck(handle);
3226 lock_release(rtld_bind_lock, &lockstate);
3232 case RTLD_DI_LINKMAP:
3233 *((struct link_map const **)p) = &obj->linkmap;
3235 case RTLD_DI_ORIGIN:
3236 error = rtld_dirname(obj->path, p);
3239 case RTLD_DI_SERINFOSIZE:
3240 case RTLD_DI_SERINFO:
3241 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3245 _rtld_error("Invalid request %d passed to dlinfo()", request);
3249 lock_release(rtld_bind_lock, &lockstate);
3255 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3258 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3259 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
3260 STAILQ_FIRST(&obj->names)->name : obj->path;
3261 phdr_info->dlpi_phdr = obj->phdr;
3262 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3263 phdr_info->dlpi_tls_modid = obj->tlsindex;
3264 phdr_info->dlpi_tls_data = obj->tlsinit;
3265 phdr_info->dlpi_adds = obj_loads;
3266 phdr_info->dlpi_subs = obj_loads - obj_count;
3270 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3272 struct dl_phdr_info phdr_info;
3273 const Obj_Entry *obj;
3274 RtldLockState bind_lockstate, phdr_lockstate;
3277 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3278 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3282 for (obj = obj_list; obj != NULL; obj = obj->next) {
3283 rtld_fill_dl_phdr_info(obj, &phdr_info);
3284 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3288 lock_release(rtld_bind_lock, &bind_lockstate);
3289 lock_release(rtld_phdr_lock, &phdr_lockstate);
3295 fill_search_info(const char *dir, size_t dirlen, void *param)
3297 struct fill_search_info_args *arg;
3301 if (arg->request == RTLD_DI_SERINFOSIZE) {
3302 arg->serinfo->dls_cnt ++;
3303 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3305 struct dl_serpath *s_entry;
3307 s_entry = arg->serpath;
3308 s_entry->dls_name = arg->strspace;
3309 s_entry->dls_flags = arg->flags;
3311 strncpy(arg->strspace, dir, dirlen);
3312 arg->strspace[dirlen] = '\0';
3314 arg->strspace += dirlen + 1;
3322 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3324 struct dl_serinfo _info;
3325 struct fill_search_info_args args;
3327 args.request = RTLD_DI_SERINFOSIZE;
3328 args.serinfo = &_info;
3330 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3333 path_enumerate(obj->rpath, fill_search_info, &args);
3334 path_enumerate(ld_library_path, fill_search_info, &args);
3335 path_enumerate(obj->runpath, fill_search_info, &args);
3336 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3337 if (!obj->z_nodeflib)
3338 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3341 if (request == RTLD_DI_SERINFOSIZE) {
3342 info->dls_size = _info.dls_size;
3343 info->dls_cnt = _info.dls_cnt;
3347 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3348 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3352 args.request = RTLD_DI_SERINFO;
3353 args.serinfo = info;
3354 args.serpath = &info->dls_serpath[0];
3355 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3357 args.flags = LA_SER_RUNPATH;
3358 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3361 args.flags = LA_SER_LIBPATH;
3362 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3365 args.flags = LA_SER_RUNPATH;
3366 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3369 args.flags = LA_SER_CONFIG;
3370 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3374 args.flags = LA_SER_DEFAULT;
3375 if (!obj->z_nodeflib &&
3376 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3382 rtld_dirname(const char *path, char *bname)
3386 /* Empty or NULL string gets treated as "." */
3387 if (path == NULL || *path == '\0') {
3393 /* Strip trailing slashes */
3394 endp = path + strlen(path) - 1;
3395 while (endp > path && *endp == '/')
3398 /* Find the start of the dir */
3399 while (endp > path && *endp != '/')
3402 /* Either the dir is "/" or there are no slashes */
3404 bname[0] = *endp == '/' ? '/' : '.';
3410 } while (endp > path && *endp == '/');
3413 if (endp - path + 2 > PATH_MAX)
3415 _rtld_error("Filename is too long: %s", path);
3419 strncpy(bname, path, endp - path + 1);
3420 bname[endp - path + 1] = '\0';
3425 rtld_dirname_abs(const char *path, char *base)
3429 if (realpath(path, base) == NULL)
3431 dbg("%s -> %s", path, base);
3432 last = strrchr(base, '/');
3441 linkmap_add(Obj_Entry *obj)
3443 struct link_map *l = &obj->linkmap;
3444 struct link_map *prev;
3446 obj->linkmap.l_name = obj->path;
3447 obj->linkmap.l_addr = obj->mapbase;
3448 obj->linkmap.l_ld = obj->dynamic;
3450 /* GDB needs load offset on MIPS to use the symbols */
3451 obj->linkmap.l_offs = obj->relocbase;
3454 if (r_debug.r_map == NULL) {
3460 * Scan to the end of the list, but not past the entry for the
3461 * dynamic linker, which we want to keep at the very end.
3463 for (prev = r_debug.r_map;
3464 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3465 prev = prev->l_next)
3468 /* Link in the new entry. */
3470 l->l_next = prev->l_next;
3471 if (l->l_next != NULL)
3472 l->l_next->l_prev = l;
3477 linkmap_delete(Obj_Entry *obj)
3479 struct link_map *l = &obj->linkmap;
3481 if (l->l_prev == NULL) {
3482 if ((r_debug.r_map = l->l_next) != NULL)
3483 l->l_next->l_prev = NULL;
3487 if ((l->l_prev->l_next = l->l_next) != NULL)
3488 l->l_next->l_prev = l->l_prev;
3492 * Function for the debugger to set a breakpoint on to gain control.
3494 * The two parameters allow the debugger to easily find and determine
3495 * what the runtime loader is doing and to whom it is doing it.
3497 * When the loadhook trap is hit (r_debug_state, set at program
3498 * initialization), the arguments can be found on the stack:
3500 * +8 struct link_map *m
3501 * +4 struct r_debug *rd
3505 r_debug_state(struct r_debug* rd, struct link_map *m)
3508 * The following is a hack to force the compiler to emit calls to
3509 * this function, even when optimizing. If the function is empty,
3510 * the compiler is not obliged to emit any code for calls to it,
3511 * even when marked __noinline. However, gdb depends on those
3514 __compiler_membar();
3518 * A function called after init routines have completed. This can be used to
3519 * break before a program's entry routine is called, and can be used when
3520 * main is not available in the symbol table.
3523 _r_debug_postinit(struct link_map *m)
3526 /* See r_debug_state(). */
3527 __compiler_membar();
3531 * Get address of the pointer variable in the main program.
3532 * Prefer non-weak symbol over the weak one.
3534 static const void **
3535 get_program_var_addr(const char *name, RtldLockState *lockstate)
3540 symlook_init(&req, name);
3541 req.lockstate = lockstate;
3542 donelist_init(&donelist);
3543 if (symlook_global(&req, &donelist) != 0)
3545 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3546 return ((const void **)make_function_pointer(req.sym_out,
3548 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3549 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3551 return ((const void **)(req.defobj_out->relocbase +
3552 req.sym_out->st_value));
3556 * Set a pointer variable in the main program to the given value. This
3557 * is used to set key variables such as "environ" before any of the
3558 * init functions are called.
3561 set_program_var(const char *name, const void *value)
3565 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3566 dbg("\"%s\": *%p <-- %p", name, addr, value);
3572 * Search the global objects, including dependencies and main object,
3573 * for the given symbol.
3576 symlook_global(SymLook *req, DoneList *donelist)
3579 const Objlist_Entry *elm;
3582 symlook_init_from_req(&req1, req);
3584 /* Search all objects loaded at program start up. */
3585 if (req->defobj_out == NULL ||
3586 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3587 res = symlook_list(&req1, &list_main, donelist);
3588 if (res == 0 && (req->defobj_out == NULL ||
3589 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3590 req->sym_out = req1.sym_out;
3591 req->defobj_out = req1.defobj_out;
3592 assert(req->defobj_out != NULL);
3596 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3597 STAILQ_FOREACH(elm, &list_global, link) {
3598 if (req->defobj_out != NULL &&
3599 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3601 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3602 if (res == 0 && (req->defobj_out == NULL ||
3603 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3604 req->sym_out = req1.sym_out;
3605 req->defobj_out = req1.defobj_out;
3606 assert(req->defobj_out != NULL);
3610 return (req->sym_out != NULL ? 0 : ESRCH);
3614 * Given a symbol name in a referencing object, find the corresponding
3615 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3616 * no definition was found. Returns a pointer to the Obj_Entry of the
3617 * defining object via the reference parameter DEFOBJ_OUT.
3620 symlook_default(SymLook *req, const Obj_Entry *refobj)
3623 const Objlist_Entry *elm;
3627 donelist_init(&donelist);
3628 symlook_init_from_req(&req1, req);
3630 /* Look first in the referencing object if linked symbolically. */
3631 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3632 res = symlook_obj(&req1, refobj);
3634 req->sym_out = req1.sym_out;
3635 req->defobj_out = req1.defobj_out;
3636 assert(req->defobj_out != NULL);
3640 symlook_global(req, &donelist);
3642 /* Search all dlopened DAGs containing the referencing object. */
3643 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3644 if (req->sym_out != NULL &&
3645 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3647 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3648 if (res == 0 && (req->sym_out == NULL ||
3649 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3650 req->sym_out = req1.sym_out;
3651 req->defobj_out = req1.defobj_out;
3652 assert(req->defobj_out != NULL);
3657 * Search the dynamic linker itself, and possibly resolve the
3658 * symbol from there. This is how the application links to
3659 * dynamic linker services such as dlopen.
3661 if (req->sym_out == NULL ||
3662 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3663 res = symlook_obj(&req1, &obj_rtld);
3665 req->sym_out = req1.sym_out;
3666 req->defobj_out = req1.defobj_out;
3667 assert(req->defobj_out != NULL);
3671 return (req->sym_out != NULL ? 0 : ESRCH);
3675 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3678 const Obj_Entry *defobj;
3679 const Objlist_Entry *elm;
3685 STAILQ_FOREACH(elm, objlist, link) {
3686 if (donelist_check(dlp, elm->obj))
3688 symlook_init_from_req(&req1, req);
3689 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3690 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3692 defobj = req1.defobj_out;
3693 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3700 req->defobj_out = defobj;
3707 * Search the chain of DAGS cointed to by the given Needed_Entry
3708 * for a symbol of the given name. Each DAG is scanned completely
3709 * before advancing to the next one. Returns a pointer to the symbol,
3710 * or NULL if no definition was found.
3713 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3716 const Needed_Entry *n;
3717 const Obj_Entry *defobj;
3723 symlook_init_from_req(&req1, req);
3724 for (n = needed; n != NULL; n = n->next) {
3725 if (n->obj == NULL ||
3726 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3728 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3730 defobj = req1.defobj_out;
3731 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3737 req->defobj_out = defobj;
3744 * Search the symbol table of a single shared object for a symbol of
3745 * the given name and version, if requested. Returns a pointer to the
3746 * symbol, or NULL if no definition was found. If the object is
3747 * filter, return filtered symbol from filtee.
3749 * The symbol's hash value is passed in for efficiency reasons; that
3750 * eliminates many recomputations of the hash value.
3753 symlook_obj(SymLook *req, const Obj_Entry *obj)
3757 int flags, res, mres;
3760 * If there is at least one valid hash at this point, we prefer to
3761 * use the faster GNU version if available.
3763 if (obj->valid_hash_gnu)
3764 mres = symlook_obj1_gnu(req, obj);
3765 else if (obj->valid_hash_sysv)
3766 mres = symlook_obj1_sysv(req, obj);
3771 if (obj->needed_filtees != NULL) {
3772 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3773 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3774 donelist_init(&donelist);
3775 symlook_init_from_req(&req1, req);
3776 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3778 req->sym_out = req1.sym_out;
3779 req->defobj_out = req1.defobj_out;
3783 if (obj->needed_aux_filtees != NULL) {
3784 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3785 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3786 donelist_init(&donelist);
3787 symlook_init_from_req(&req1, req);
3788 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3790 req->sym_out = req1.sym_out;
3791 req->defobj_out = req1.defobj_out;
3799 /* Symbol match routine common to both hash functions */
3801 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3802 const unsigned long symnum)
3805 const Elf_Sym *symp;
3808 symp = obj->symtab + symnum;
3809 strp = obj->strtab + symp->st_name;
3811 switch (ELF_ST_TYPE(symp->st_info)) {
3817 if (symp->st_value == 0)
3821 if (symp->st_shndx != SHN_UNDEF)
3824 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3825 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3832 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3835 if (req->ventry == NULL) {
3836 if (obj->versyms != NULL) {
3837 verndx = VER_NDX(obj->versyms[symnum]);
3838 if (verndx > obj->vernum) {
3840 "%s: symbol %s references wrong version %d",
3841 obj->path, obj->strtab + symnum, verndx);
3845 * If we are not called from dlsym (i.e. this
3846 * is a normal relocation from unversioned
3847 * binary), accept the symbol immediately if
3848 * it happens to have first version after this
3849 * shared object became versioned. Otherwise,
3850 * if symbol is versioned and not hidden,
3851 * remember it. If it is the only symbol with
3852 * this name exported by the shared object, it
3853 * will be returned as a match by the calling
3854 * function. If symbol is global (verndx < 2)
3855 * accept it unconditionally.
3857 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3858 verndx == VER_NDX_GIVEN) {
3859 result->sym_out = symp;
3862 else if (verndx >= VER_NDX_GIVEN) {
3863 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
3865 if (result->vsymp == NULL)
3866 result->vsymp = symp;
3872 result->sym_out = symp;
3875 if (obj->versyms == NULL) {
3876 if (object_match_name(obj, req->ventry->name)) {
3877 _rtld_error("%s: object %s should provide version %s "
3878 "for symbol %s", obj_rtld.path, obj->path,
3879 req->ventry->name, obj->strtab + symnum);
3883 verndx = VER_NDX(obj->versyms[symnum]);
3884 if (verndx > obj->vernum) {
3885 _rtld_error("%s: symbol %s references wrong version %d",
3886 obj->path, obj->strtab + symnum, verndx);
3889 if (obj->vertab[verndx].hash != req->ventry->hash ||
3890 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3892 * Version does not match. Look if this is a
3893 * global symbol and if it is not hidden. If
3894 * global symbol (verndx < 2) is available,
3895 * use it. Do not return symbol if we are
3896 * called by dlvsym, because dlvsym looks for
3897 * a specific version and default one is not
3898 * what dlvsym wants.
3900 if ((req->flags & SYMLOOK_DLSYM) ||
3901 (verndx >= VER_NDX_GIVEN) ||
3902 (obj->versyms[symnum] & VER_NDX_HIDDEN))
3906 result->sym_out = symp;
3911 * Search for symbol using SysV hash function.
3912 * obj->buckets is known not to be NULL at this point; the test for this was
3913 * performed with the obj->valid_hash_sysv assignment.
3916 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
3918 unsigned long symnum;
3919 Sym_Match_Result matchres;
3921 matchres.sym_out = NULL;
3922 matchres.vsymp = NULL;
3923 matchres.vcount = 0;
3925 for (symnum = obj->buckets[req->hash % obj->nbuckets];
3926 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
3927 if (symnum >= obj->nchains)
3928 return (ESRCH); /* Bad object */
3930 if (matched_symbol(req, obj, &matchres, symnum)) {
3931 req->sym_out = matchres.sym_out;
3932 req->defobj_out = obj;
3936 if (matchres.vcount == 1) {
3937 req->sym_out = matchres.vsymp;
3938 req->defobj_out = obj;
3944 /* Search for symbol using GNU hash function */
3946 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
3948 Elf_Addr bloom_word;
3949 const Elf32_Word *hashval;
3951 Sym_Match_Result matchres;
3952 unsigned int h1, h2;
3953 unsigned long symnum;
3955 matchres.sym_out = NULL;
3956 matchres.vsymp = NULL;
3957 matchres.vcount = 0;
3959 /* Pick right bitmask word from Bloom filter array */
3960 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
3961 obj->maskwords_bm_gnu];
3963 /* Calculate modulus word size of gnu hash and its derivative */
3964 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
3965 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
3967 /* Filter out the "definitely not in set" queries */
3968 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
3971 /* Locate hash chain and corresponding value element*/
3972 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
3975 hashval = &obj->chain_zero_gnu[bucket];
3977 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
3978 symnum = hashval - obj->chain_zero_gnu;
3979 if (matched_symbol(req, obj, &matchres, symnum)) {
3980 req->sym_out = matchres.sym_out;
3981 req->defobj_out = obj;
3985 } while ((*hashval++ & 1) == 0);
3986 if (matchres.vcount == 1) {
3987 req->sym_out = matchres.vsymp;
3988 req->defobj_out = obj;
3995 trace_loaded_objects(Obj_Entry *obj)
3997 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4000 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
4003 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
4004 fmt1 = "\t%o => %p (%x)\n";
4006 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
4007 fmt2 = "\t%o (%x)\n";
4009 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
4011 for (; obj; obj = obj->next) {
4012 Needed_Entry *needed;
4016 if (list_containers && obj->needed != NULL)
4017 rtld_printf("%s:\n", obj->path);
4018 for (needed = obj->needed; needed; needed = needed->next) {
4019 if (needed->obj != NULL) {
4020 if (needed->obj->traced && !list_containers)
4022 needed->obj->traced = true;
4023 path = needed->obj->path;
4027 name = (char *)obj->strtab + needed->name;
4028 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4030 fmt = is_lib ? fmt1 : fmt2;
4031 while ((c = *fmt++) != '\0') {
4057 rtld_putstr(main_local);
4060 rtld_putstr(obj_main->path);
4067 rtld_printf("%d", sodp->sod_major);
4070 rtld_printf("%d", sodp->sod_minor);
4077 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4090 * Unload a dlopened object and its dependencies from memory and from
4091 * our data structures. It is assumed that the DAG rooted in the
4092 * object has already been unreferenced, and that the object has a
4093 * reference count of 0.
4096 unload_object(Obj_Entry *root)
4101 assert(root->refcount == 0);
4104 * Pass over the DAG removing unreferenced objects from
4105 * appropriate lists.
4107 unlink_object(root);
4109 /* Unmap all objects that are no longer referenced. */
4110 linkp = &obj_list->next;
4111 while ((obj = *linkp) != NULL) {
4112 if (obj->refcount == 0) {
4113 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4115 dbg("unloading \"%s\"", obj->path);
4116 unload_filtees(root);
4117 munmap(obj->mapbase, obj->mapsize);
4118 linkmap_delete(obj);
4129 unlink_object(Obj_Entry *root)
4133 if (root->refcount == 0) {
4134 /* Remove the object from the RTLD_GLOBAL list. */
4135 objlist_remove(&list_global, root);
4137 /* Remove the object from all objects' DAG lists. */
4138 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4139 objlist_remove(&elm->obj->dldags, root);
4140 if (elm->obj != root)
4141 unlink_object(elm->obj);
4147 ref_dag(Obj_Entry *root)
4151 assert(root->dag_inited);
4152 STAILQ_FOREACH(elm, &root->dagmembers, link)
4153 elm->obj->refcount++;
4157 unref_dag(Obj_Entry *root)
4161 assert(root->dag_inited);
4162 STAILQ_FOREACH(elm, &root->dagmembers, link)
4163 elm->obj->refcount--;
4167 * Common code for MD __tls_get_addr().
4169 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4171 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4173 Elf_Addr *newdtv, *dtv;
4174 RtldLockState lockstate;
4178 /* Check dtv generation in case new modules have arrived */
4179 if (dtv[0] != tls_dtv_generation) {
4180 wlock_acquire(rtld_bind_lock, &lockstate);
4181 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4183 if (to_copy > tls_max_index)
4184 to_copy = tls_max_index;
4185 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4186 newdtv[0] = tls_dtv_generation;
4187 newdtv[1] = tls_max_index;
4189 lock_release(rtld_bind_lock, &lockstate);
4190 dtv = *dtvp = newdtv;
4193 /* Dynamically allocate module TLS if necessary */
4194 if (dtv[index + 1] == 0) {
4195 /* Signal safe, wlock will block out signals. */
4196 wlock_acquire(rtld_bind_lock, &lockstate);
4197 if (!dtv[index + 1])
4198 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4199 lock_release(rtld_bind_lock, &lockstate);
4201 return ((void *)(dtv[index + 1] + offset));
4205 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4210 /* Check dtv generation in case new modules have arrived */
4211 if (__predict_true(dtv[0] == tls_dtv_generation &&
4212 dtv[index + 1] != 0))
4213 return ((void *)(dtv[index + 1] + offset));
4214 return (tls_get_addr_slow(dtvp, index, offset));
4217 #if defined(__arm__) || defined(__ia64__) || defined(__powerpc__)
4220 * Allocate Static TLS using the Variant I method.
4223 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4232 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4235 assert(tcbsize >= TLS_TCB_SIZE);
4236 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4237 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4239 if (oldtcb != NULL) {
4240 memcpy(tls, oldtcb, tls_static_space);
4243 /* Adjust the DTV. */
4245 for (i = 0; i < dtv[1]; i++) {
4246 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4247 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4248 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4252 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4254 dtv[0] = tls_dtv_generation;
4255 dtv[1] = tls_max_index;
4257 for (obj = objs; obj; obj = obj->next) {
4258 if (obj->tlsoffset > 0) {
4259 addr = (Elf_Addr)tls + obj->tlsoffset;
4260 if (obj->tlsinitsize > 0)
4261 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4262 if (obj->tlssize > obj->tlsinitsize)
4263 memset((void*) (addr + obj->tlsinitsize), 0,
4264 obj->tlssize - obj->tlsinitsize);
4265 dtv[obj->tlsindex + 1] = addr;
4274 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4277 Elf_Addr tlsstart, tlsend;
4280 assert(tcbsize >= TLS_TCB_SIZE);
4282 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4283 tlsend = tlsstart + tls_static_space;
4285 dtv = *(Elf_Addr **)tlsstart;
4287 for (i = 0; i < dtvsize; i++) {
4288 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4289 free((void*)dtv[i+2]);
4298 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \
4302 * Allocate Static TLS using the Variant II method.
4305 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4308 size_t size, ralign;
4310 Elf_Addr *dtv, *olddtv;
4311 Elf_Addr segbase, oldsegbase, addr;
4315 if (tls_static_max_align > ralign)
4316 ralign = tls_static_max_align;
4317 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4319 assert(tcbsize >= 2*sizeof(Elf_Addr));
4320 tls = malloc_aligned(size, ralign);
4321 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4323 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4324 ((Elf_Addr*)segbase)[0] = segbase;
4325 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4327 dtv[0] = tls_dtv_generation;
4328 dtv[1] = tls_max_index;
4332 * Copy the static TLS block over whole.
4334 oldsegbase = (Elf_Addr) oldtls;
4335 memcpy((void *)(segbase - tls_static_space),
4336 (const void *)(oldsegbase - tls_static_space),
4340 * If any dynamic TLS blocks have been created tls_get_addr(),
4343 olddtv = ((Elf_Addr**)oldsegbase)[1];
4344 for (i = 0; i < olddtv[1]; i++) {
4345 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4346 dtv[i+2] = olddtv[i+2];
4352 * We assume that this block was the one we created with
4353 * allocate_initial_tls().
4355 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4357 for (obj = objs; obj; obj = obj->next) {
4358 if (obj->tlsoffset) {
4359 addr = segbase - obj->tlsoffset;
4360 memset((void*) (addr + obj->tlsinitsize),
4361 0, obj->tlssize - obj->tlsinitsize);
4363 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4364 dtv[obj->tlsindex + 1] = addr;
4369 return (void*) segbase;
4373 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4376 size_t size, ralign;
4378 Elf_Addr tlsstart, tlsend;
4381 * Figure out the size of the initial TLS block so that we can
4382 * find stuff which ___tls_get_addr() allocated dynamically.
4385 if (tls_static_max_align > ralign)
4386 ralign = tls_static_max_align;
4387 size = round(tls_static_space, ralign);
4389 dtv = ((Elf_Addr**)tls)[1];
4391 tlsend = (Elf_Addr) tls;
4392 tlsstart = tlsend - size;
4393 for (i = 0; i < dtvsize; i++) {
4394 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4395 free_aligned((void *)dtv[i + 2]);
4399 free_aligned((void *)tlsstart);
4406 * Allocate TLS block for module with given index.
4409 allocate_module_tls(int index)
4414 for (obj = obj_list; obj; obj = obj->next) {
4415 if (obj->tlsindex == index)
4419 _rtld_error("Can't find module with TLS index %d", index);
4423 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4424 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4425 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4431 allocate_tls_offset(Obj_Entry *obj)
4438 if (obj->tlssize == 0) {
4439 obj->tls_done = true;
4443 if (obj->tlsindex == 1)
4444 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4446 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4447 obj->tlssize, obj->tlsalign);
4450 * If we have already fixed the size of the static TLS block, we
4451 * must stay within that size. When allocating the static TLS, we
4452 * leave a small amount of space spare to be used for dynamically
4453 * loading modules which use static TLS.
4455 if (tls_static_space != 0) {
4456 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4458 } else if (obj->tlsalign > tls_static_max_align) {
4459 tls_static_max_align = obj->tlsalign;
4462 tls_last_offset = obj->tlsoffset = off;
4463 tls_last_size = obj->tlssize;
4464 obj->tls_done = true;
4470 free_tls_offset(Obj_Entry *obj)
4474 * If we were the last thing to allocate out of the static TLS
4475 * block, we give our space back to the 'allocator'. This is a
4476 * simplistic workaround to allow libGL.so.1 to be loaded and
4477 * unloaded multiple times.
4479 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4480 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4481 tls_last_offset -= obj->tlssize;
4487 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4490 RtldLockState lockstate;
4492 wlock_acquire(rtld_bind_lock, &lockstate);
4493 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4494 lock_release(rtld_bind_lock, &lockstate);
4499 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4501 RtldLockState lockstate;
4503 wlock_acquire(rtld_bind_lock, &lockstate);
4504 free_tls(tcb, tcbsize, tcbalign);
4505 lock_release(rtld_bind_lock, &lockstate);
4509 object_add_name(Obj_Entry *obj, const char *name)
4515 entry = malloc(sizeof(Name_Entry) + len);
4517 if (entry != NULL) {
4518 strcpy(entry->name, name);
4519 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4524 object_match_name(const Obj_Entry *obj, const char *name)
4528 STAILQ_FOREACH(entry, &obj->names, link) {
4529 if (strcmp(name, entry->name) == 0)
4536 locate_dependency(const Obj_Entry *obj, const char *name)
4538 const Objlist_Entry *entry;
4539 const Needed_Entry *needed;
4541 STAILQ_FOREACH(entry, &list_main, link) {
4542 if (object_match_name(entry->obj, name))
4546 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4547 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4548 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4550 * If there is DT_NEEDED for the name we are looking for,
4551 * we are all set. Note that object might not be found if
4552 * dependency was not loaded yet, so the function can
4553 * return NULL here. This is expected and handled
4554 * properly by the caller.
4556 return (needed->obj);
4559 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4565 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4566 const Elf_Vernaux *vna)
4568 const Elf_Verdef *vd;
4569 const char *vername;
4571 vername = refobj->strtab + vna->vna_name;
4572 vd = depobj->verdef;
4574 _rtld_error("%s: version %s required by %s not defined",
4575 depobj->path, vername, refobj->path);
4579 if (vd->vd_version != VER_DEF_CURRENT) {
4580 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4581 depobj->path, vd->vd_version);
4584 if (vna->vna_hash == vd->vd_hash) {
4585 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4586 ((char *)vd + vd->vd_aux);
4587 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4590 if (vd->vd_next == 0)
4592 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4594 if (vna->vna_flags & VER_FLG_WEAK)
4596 _rtld_error("%s: version %s required by %s not found",
4597 depobj->path, vername, refobj->path);
4602 rtld_verify_object_versions(Obj_Entry *obj)
4604 const Elf_Verneed *vn;
4605 const Elf_Verdef *vd;
4606 const Elf_Verdaux *vda;
4607 const Elf_Vernaux *vna;
4608 const Obj_Entry *depobj;
4609 int maxvernum, vernum;
4611 if (obj->ver_checked)
4613 obj->ver_checked = true;
4617 * Walk over defined and required version records and figure out
4618 * max index used by any of them. Do very basic sanity checking
4622 while (vn != NULL) {
4623 if (vn->vn_version != VER_NEED_CURRENT) {
4624 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4625 obj->path, vn->vn_version);
4628 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4630 vernum = VER_NEED_IDX(vna->vna_other);
4631 if (vernum > maxvernum)
4633 if (vna->vna_next == 0)
4635 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4637 if (vn->vn_next == 0)
4639 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4643 while (vd != NULL) {
4644 if (vd->vd_version != VER_DEF_CURRENT) {
4645 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4646 obj->path, vd->vd_version);
4649 vernum = VER_DEF_IDX(vd->vd_ndx);
4650 if (vernum > maxvernum)
4652 if (vd->vd_next == 0)
4654 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4661 * Store version information in array indexable by version index.
4662 * Verify that object version requirements are satisfied along the
4665 obj->vernum = maxvernum + 1;
4666 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4669 while (vd != NULL) {
4670 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4671 vernum = VER_DEF_IDX(vd->vd_ndx);
4672 assert(vernum <= maxvernum);
4673 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4674 obj->vertab[vernum].hash = vd->vd_hash;
4675 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4676 obj->vertab[vernum].file = NULL;
4677 obj->vertab[vernum].flags = 0;
4679 if (vd->vd_next == 0)
4681 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4685 while (vn != NULL) {
4686 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4689 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4691 if (check_object_provided_version(obj, depobj, vna))
4693 vernum = VER_NEED_IDX(vna->vna_other);
4694 assert(vernum <= maxvernum);
4695 obj->vertab[vernum].hash = vna->vna_hash;
4696 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4697 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4698 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4699 VER_INFO_HIDDEN : 0;
4700 if (vna->vna_next == 0)
4702 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4704 if (vn->vn_next == 0)
4706 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4712 rtld_verify_versions(const Objlist *objlist)
4714 Objlist_Entry *entry;
4718 STAILQ_FOREACH(entry, objlist, link) {
4720 * Skip dummy objects or objects that have their version requirements
4723 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4725 if (rtld_verify_object_versions(entry->obj) == -1) {
4727 if (ld_tracing == NULL)
4731 if (rc == 0 || ld_tracing != NULL)
4732 rc = rtld_verify_object_versions(&obj_rtld);
4737 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4742 vernum = VER_NDX(obj->versyms[symnum]);
4743 if (vernum >= obj->vernum) {
4744 _rtld_error("%s: symbol %s has wrong verneed value %d",
4745 obj->path, obj->strtab + symnum, vernum);
4746 } else if (obj->vertab[vernum].hash != 0) {
4747 return &obj->vertab[vernum];
4754 _rtld_get_stack_prot(void)
4757 return (stack_prot);
4761 map_stacks_exec(RtldLockState *lockstate)
4763 void (*thr_map_stacks_exec)(void);
4765 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4767 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4768 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4769 if (thr_map_stacks_exec != NULL) {
4770 stack_prot |= PROT_EXEC;
4771 thr_map_stacks_exec();
4776 symlook_init(SymLook *dst, const char *name)
4779 bzero(dst, sizeof(*dst));
4781 dst->hash = elf_hash(name);
4782 dst->hash_gnu = gnu_hash(name);
4786 symlook_init_from_req(SymLook *dst, const SymLook *src)
4789 dst->name = src->name;
4790 dst->hash = src->hash;
4791 dst->hash_gnu = src->hash_gnu;
4792 dst->ventry = src->ventry;
4793 dst->flags = src->flags;
4794 dst->defobj_out = NULL;
4795 dst->sym_out = NULL;
4796 dst->lockstate = src->lockstate;
4800 * Overrides for libc_pic-provided functions.
4804 __getosreldate(void)
4814 oid[1] = KERN_OSRELDATE;
4816 len = sizeof(osrel);
4817 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4818 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4830 void (*__cleanup)(void);
4831 int __isthreaded = 0;
4832 int _thread_autoinit_dummy_decl = 1;
4835 * No unresolved symbols for rtld.
4838 __pthread_cxa_finalize(struct dl_phdr_info *a)
4843 __stack_chk_fail(void)
4846 _rtld_error("stack overflow detected; terminated");
4849 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
4855 _rtld_error("buffer overflow detected; terminated");
4860 rtld_strerror(int errnum)
4863 if (errnum < 0 || errnum >= sys_nerr)
4864 return ("Unknown error");
4865 return (sys_errlist[errnum]);