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 *, int *);
98 static const char *gethints(bool);
99 static void init_dag(Obj_Entry *);
100 static void init_pagesizes(Elf_Auxinfo **aux_info);
101 static void init_rtld(caddr_t, Elf_Auxinfo **);
102 static void initlist_add_neededs(Needed_Entry *, Objlist *);
103 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
104 static void linkmap_add(Obj_Entry *);
105 static void linkmap_delete(Obj_Entry *);
106 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
107 static void unload_filtees(Obj_Entry *);
108 static int load_needed_objects(Obj_Entry *, int);
109 static int load_preload_objects(void);
110 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
111 static void map_stacks_exec(RtldLockState *);
112 static Obj_Entry *obj_from_addr(const void *);
113 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
114 static void objlist_call_init(Objlist *, RtldLockState *);
115 static void objlist_clear(Objlist *);
116 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
117 static void objlist_init(Objlist *);
118 static void objlist_push_head(Objlist *, Obj_Entry *);
119 static void objlist_push_tail(Objlist *, Obj_Entry *);
120 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
121 static void objlist_remove(Objlist *, Obj_Entry *);
122 static int parse_libdir(const char *);
123 static void *path_enumerate(const char *, path_enum_proc, void *);
124 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
125 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
126 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
127 int flags, RtldLockState *lockstate);
128 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
130 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
131 int flags, RtldLockState *lockstate);
132 static int rtld_dirname(const char *, char *);
133 static int rtld_dirname_abs(const char *, char *);
134 static void *rtld_dlopen(const char *name, int fd, int mode);
135 static void rtld_exit(void);
136 static char *search_library_path(const char *, const char *);
137 static char *search_library_pathfds(const char *, const char *, int *);
138 static const void **get_program_var_addr(const char *, RtldLockState *);
139 static void set_program_var(const char *, const void *);
140 static int symlook_default(SymLook *, const Obj_Entry *refobj);
141 static int symlook_global(SymLook *, DoneList *);
142 static void symlook_init_from_req(SymLook *, const SymLook *);
143 static int symlook_list(SymLook *, const Objlist *, DoneList *);
144 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
145 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
146 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
147 static void trace_loaded_objects(Obj_Entry *);
148 static void unlink_object(Obj_Entry *);
149 static void unload_object(Obj_Entry *);
150 static void unref_dag(Obj_Entry *);
151 static void ref_dag(Obj_Entry *);
152 static char *origin_subst_one(char *, const char *, const char *, bool);
153 static char *origin_subst(char *, const char *);
154 static void preinit_main(void);
155 static int rtld_verify_versions(const Objlist *);
156 static int rtld_verify_object_versions(Obj_Entry *);
157 static void object_add_name(Obj_Entry *, const char *);
158 static int object_match_name(const Obj_Entry *, const char *);
159 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
160 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
161 struct dl_phdr_info *phdr_info);
162 static uint32_t gnu_hash(const char *);
163 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
164 const unsigned long);
166 void r_debug_state(struct r_debug *, struct link_map *) __noinline;
167 void _r_debug_postinit(struct link_map *) __noinline;
172 static char *error_message; /* Message for dlerror(), or NULL */
173 struct r_debug r_debug; /* for GDB; */
174 static bool libmap_disable; /* Disable libmap */
175 static bool ld_loadfltr; /* Immediate filters processing */
176 static char *libmap_override; /* Maps to use in addition to libmap.conf */
177 static bool trust; /* False for setuid and setgid programs */
178 static bool dangerous_ld_env; /* True if environment variables have been
179 used to affect the libraries loaded */
180 static char *ld_bind_now; /* Environment variable for immediate binding */
181 static char *ld_debug; /* Environment variable for debugging */
182 static char *ld_library_path; /* Environment variable for search path */
183 static char *ld_library_dirs; /* Environment variable for library descriptors */
184 static char *ld_preload; /* Environment variable for libraries to
186 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
187 static char *ld_tracing; /* Called from ldd to print libs */
188 static char *ld_utrace; /* Use utrace() to log events. */
189 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
190 static Obj_Entry **obj_tail; /* Link field of last object in list */
191 static Obj_Entry *obj_main; /* The main program shared object */
192 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
193 static unsigned int obj_count; /* Number of objects in obj_list */
194 static unsigned int obj_loads; /* Number of objects in obj_list */
196 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
197 STAILQ_HEAD_INITIALIZER(list_global);
198 static Objlist list_main = /* Objects loaded at program startup */
199 STAILQ_HEAD_INITIALIZER(list_main);
200 static Objlist list_fini = /* Objects needing fini() calls */
201 STAILQ_HEAD_INITIALIZER(list_fini);
203 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
205 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
207 extern Elf_Dyn _DYNAMIC;
208 #pragma weak _DYNAMIC
209 #ifndef RTLD_IS_DYNAMIC
210 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
213 int npagesizes, osreldate;
216 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
218 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
219 static int max_stack_flags;
222 * Global declarations normally provided by crt1. The dynamic linker is
223 * not built with crt1, so we have to provide them ourselves.
229 * Used to pass argc, argv to init functions.
235 * Globals to control TLS allocation.
237 size_t tls_last_offset; /* Static TLS offset of last module */
238 size_t tls_last_size; /* Static TLS size of last module */
239 size_t tls_static_space; /* Static TLS space allocated */
240 size_t tls_static_max_align;
241 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
242 int tls_max_index = 1; /* Largest module index allocated */
244 bool ld_library_path_rpath = false;
247 * Fill in a DoneList with an allocation large enough to hold all of
248 * the currently-loaded objects. Keep this as a macro since it calls
249 * alloca and we want that to occur within the scope of the caller.
251 #define donelist_init(dlp) \
252 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
253 assert((dlp)->objs != NULL), \
254 (dlp)->num_alloc = obj_count, \
257 #define UTRACE_DLOPEN_START 1
258 #define UTRACE_DLOPEN_STOP 2
259 #define UTRACE_DLCLOSE_START 3
260 #define UTRACE_DLCLOSE_STOP 4
261 #define UTRACE_LOAD_OBJECT 5
262 #define UTRACE_UNLOAD_OBJECT 6
263 #define UTRACE_ADD_RUNDEP 7
264 #define UTRACE_PRELOAD_FINISHED 8
265 #define UTRACE_INIT_CALL 9
266 #define UTRACE_FINI_CALL 10
269 char sig[4]; /* 'RTLD' */
272 void *mapbase; /* Used for 'parent' and 'init/fini' */
274 int refcnt; /* Used for 'mode' */
275 char name[MAXPATHLEN];
278 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
279 if (ld_utrace != NULL) \
280 ld_utrace_log(e, h, mb, ms, r, n); \
284 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
285 int refcnt, const char *name)
287 struct utrace_rtld ut;
295 ut.mapbase = mapbase;
296 ut.mapsize = mapsize;
298 bzero(ut.name, sizeof(ut.name));
300 strlcpy(ut.name, name, sizeof(ut.name));
301 utrace(&ut, sizeof(ut));
305 * Main entry point for dynamic linking. The first argument is the
306 * stack pointer. The stack is expected to be laid out as described
307 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
308 * Specifically, the stack pointer points to a word containing
309 * ARGC. Following that in the stack is a null-terminated sequence
310 * of pointers to argument strings. Then comes a null-terminated
311 * sequence of pointers to environment strings. Finally, there is a
312 * sequence of "auxiliary vector" entries.
314 * The second argument points to a place to store the dynamic linker's
315 * exit procedure pointer and the third to a place to store the main
318 * The return value is the main program's entry point.
321 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
323 Elf_Auxinfo *aux_info[AT_COUNT];
331 Objlist_Entry *entry;
333 Obj_Entry **preload_tail;
334 Obj_Entry *last_interposer;
336 RtldLockState lockstate;
337 char *library_path_rpath;
342 * On entry, the dynamic linker itself has not been relocated yet.
343 * Be very careful not to reference any global data until after
344 * init_rtld has returned. It is OK to reference file-scope statics
345 * and string constants, and to call static and global functions.
348 /* Find the auxiliary vector on the stack. */
351 sp += argc + 1; /* Skip over arguments and NULL terminator */
353 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
355 aux = (Elf_Auxinfo *) sp;
357 /* Digest the auxiliary vector. */
358 for (i = 0; i < AT_COUNT; i++)
360 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
361 if (auxp->a_type < AT_COUNT)
362 aux_info[auxp->a_type] = auxp;
365 /* Initialize and relocate ourselves. */
366 assert(aux_info[AT_BASE] != NULL);
367 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
369 __progname = obj_rtld.path;
370 argv0 = argv[0] != NULL ? argv[0] : "(null)";
375 if (aux_info[AT_CANARY] != NULL &&
376 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
377 i = aux_info[AT_CANARYLEN]->a_un.a_val;
378 if (i > sizeof(__stack_chk_guard))
379 i = sizeof(__stack_chk_guard);
380 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
385 len = sizeof(__stack_chk_guard);
386 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
387 len != sizeof(__stack_chk_guard)) {
388 /* If sysctl was unsuccessful, use the "terminator canary". */
389 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
390 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
391 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
392 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
396 trust = !issetugid();
398 ld_bind_now = getenv(LD_ "BIND_NOW");
400 * If the process is tainted, then we un-set the dangerous environment
401 * variables. The process will be marked as tainted until setuid(2)
402 * is called. If any child process calls setuid(2) we do not want any
403 * future processes to honor the potentially un-safe variables.
406 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
407 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBRARY_PATH_FDS") ||
408 unsetenv(LD_ "LIBMAP_DISABLE") ||
409 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
410 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) {
411 _rtld_error("environment corrupt; aborting");
415 ld_debug = getenv(LD_ "DEBUG");
416 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
417 libmap_override = getenv(LD_ "LIBMAP");
418 ld_library_path = getenv(LD_ "LIBRARY_PATH");
419 ld_library_dirs = getenv(LD_ "LIBRARY_PATH_FDS");
420 ld_preload = getenv(LD_ "PRELOAD");
421 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
422 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
423 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH");
424 if (library_path_rpath != NULL) {
425 if (library_path_rpath[0] == 'y' ||
426 library_path_rpath[0] == 'Y' ||
427 library_path_rpath[0] == '1')
428 ld_library_path_rpath = true;
430 ld_library_path_rpath = false;
432 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
433 (ld_library_path != NULL) || (ld_preload != NULL) ||
434 (ld_elf_hints_path != NULL) || ld_loadfltr;
435 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
436 ld_utrace = getenv(LD_ "UTRACE");
438 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
439 ld_elf_hints_path = _PATH_ELF_HINTS;
441 if (ld_debug != NULL && *ld_debug != '\0')
443 dbg("%s is initialized, base address = %p", __progname,
444 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
445 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
446 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
448 dbg("initializing thread locks");
452 * Load the main program, or process its program header if it is
455 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
456 int fd = aux_info[AT_EXECFD]->a_un.a_val;
457 dbg("loading main program");
458 obj_main = map_object(fd, argv0, NULL);
460 if (obj_main == NULL)
462 max_stack_flags = obj->stack_flags;
463 } else { /* Main program already loaded. */
464 const Elf_Phdr *phdr;
468 dbg("processing main program's program header");
469 assert(aux_info[AT_PHDR] != NULL);
470 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
471 assert(aux_info[AT_PHNUM] != NULL);
472 phnum = aux_info[AT_PHNUM]->a_un.a_val;
473 assert(aux_info[AT_PHENT] != NULL);
474 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
475 assert(aux_info[AT_ENTRY] != NULL);
476 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
477 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
481 if (aux_info[AT_EXECPATH] != 0) {
483 char buf[MAXPATHLEN];
485 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
486 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
487 if (kexecpath[0] == '/')
488 obj_main->path = kexecpath;
489 else if (getcwd(buf, sizeof(buf)) == NULL ||
490 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
491 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
492 obj_main->path = xstrdup(argv0);
494 obj_main->path = xstrdup(buf);
496 dbg("No AT_EXECPATH");
497 obj_main->path = xstrdup(argv0);
499 dbg("obj_main path %s", obj_main->path);
500 obj_main->mainprog = true;
502 if (aux_info[AT_STACKPROT] != NULL &&
503 aux_info[AT_STACKPROT]->a_un.a_val != 0)
504 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
507 * Get the actual dynamic linker pathname from the executable if
508 * possible. (It should always be possible.) That ensures that
509 * gdb will find the right dynamic linker even if a non-standard
512 if (obj_main->interp != NULL &&
513 strcmp(obj_main->interp, obj_rtld.path) != 0) {
515 obj_rtld.path = xstrdup(obj_main->interp);
516 __progname = obj_rtld.path;
519 digest_dynamic(obj_main, 0);
520 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
521 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
522 obj_main->dynsymcount);
524 linkmap_add(obj_main);
525 linkmap_add(&obj_rtld);
527 /* Link the main program into the list of objects. */
528 *obj_tail = obj_main;
529 obj_tail = &obj_main->next;
533 /* Initialize a fake symbol for resolving undefined weak references. */
534 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
535 sym_zero.st_shndx = SHN_UNDEF;
536 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
539 libmap_disable = (bool)lm_init(libmap_override);
541 dbg("loading LD_PRELOAD libraries");
542 if (load_preload_objects() == -1)
544 preload_tail = obj_tail;
546 dbg("loading needed objects");
547 if (load_needed_objects(obj_main, 0) == -1)
550 /* Make a list of all objects loaded at startup. */
551 last_interposer = obj_main;
552 for (obj = obj_list; obj != NULL; obj = obj->next) {
553 if (obj->z_interpose && obj != obj_main) {
554 objlist_put_after(&list_main, last_interposer, obj);
555 last_interposer = obj;
557 objlist_push_tail(&list_main, obj);
562 dbg("checking for required versions");
563 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
566 if (ld_tracing) { /* We're done */
567 trace_loaded_objects(obj_main);
571 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
572 dump_relocations(obj_main);
577 * Processing tls relocations requires having the tls offsets
578 * initialized. Prepare offsets before starting initial
579 * relocation processing.
581 dbg("initializing initial thread local storage offsets");
582 STAILQ_FOREACH(entry, &list_main, link) {
584 * Allocate all the initial objects out of the static TLS
585 * block even if they didn't ask for it.
587 allocate_tls_offset(entry->obj);
590 if (relocate_objects(obj_main,
591 ld_bind_now != NULL && *ld_bind_now != '\0',
592 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
595 dbg("doing copy relocations");
596 if (do_copy_relocations(obj_main) == -1)
599 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
600 dump_relocations(obj_main);
605 * Setup TLS for main thread. This must be done after the
606 * relocations are processed, since tls initialization section
607 * might be the subject for relocations.
609 dbg("initializing initial thread local storage");
610 allocate_initial_tls(obj_list);
612 dbg("initializing key program variables");
613 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
614 set_program_var("environ", env);
615 set_program_var("__elf_aux_vector", aux);
617 /* Make a list of init functions to call. */
618 objlist_init(&initlist);
619 initlist_add_objects(obj_list, preload_tail, &initlist);
621 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
623 map_stacks_exec(NULL);
625 dbg("resolving ifuncs");
626 if (resolve_objects_ifunc(obj_main,
627 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
631 if (!obj_main->crt_no_init) {
633 * Make sure we don't call the main program's init and fini
634 * functions for binaries linked with old crt1 which calls
637 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
638 obj_main->preinit_array = obj_main->init_array =
639 obj_main->fini_array = (Elf_Addr)NULL;
642 wlock_acquire(rtld_bind_lock, &lockstate);
643 if (obj_main->crt_no_init)
645 objlist_call_init(&initlist, &lockstate);
646 _r_debug_postinit(&obj_main->linkmap);
647 objlist_clear(&initlist);
648 dbg("loading filtees");
649 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
650 if (ld_loadfltr || obj->z_loadfltr)
651 load_filtees(obj, 0, &lockstate);
653 lock_release(rtld_bind_lock, &lockstate);
655 dbg("transferring control to program entry point = %p", obj_main->entry);
657 /* Return the exit procedure and the program entry point. */
658 *exit_proc = rtld_exit;
660 return (func_ptr_type) obj_main->entry;
664 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
669 ptr = (void *)make_function_pointer(def, obj);
670 target = ((Elf_Addr (*)(void))ptr)();
671 return ((void *)target);
675 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
679 const Obj_Entry *defobj;
682 RtldLockState lockstate;
684 rlock_acquire(rtld_bind_lock, &lockstate);
685 if (sigsetjmp(lockstate.env, 0) != 0)
686 lock_upgrade(rtld_bind_lock, &lockstate);
688 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
690 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
692 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
693 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
697 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
698 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
700 target = (Elf_Addr)(defobj->relocbase + def->st_value);
702 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
703 defobj->strtab + def->st_name, basename(obj->path),
704 (void *)target, basename(defobj->path));
707 * Write the new contents for the jmpslot. Note that depending on
708 * architecture, the value which we need to return back to the
709 * lazy binding trampoline may or may not be the target
710 * address. The value returned from reloc_jmpslot() is the value
711 * that the trampoline needs.
713 target = reloc_jmpslot(where, target, defobj, obj, rel);
714 lock_release(rtld_bind_lock, &lockstate);
719 * Error reporting function. Use it like printf. If formats the message
720 * into a buffer, and sets things up so that the next call to dlerror()
721 * will return the message.
724 _rtld_error(const char *fmt, ...)
726 static char buf[512];
730 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
736 * Return a dynamically-allocated copy of the current error message, if any.
741 return error_message == NULL ? NULL : xstrdup(error_message);
745 * Restore the current error message from a copy which was previously saved
746 * by errmsg_save(). The copy is freed.
749 errmsg_restore(char *saved_msg)
751 if (saved_msg == NULL)
752 error_message = NULL;
754 _rtld_error("%s", saved_msg);
760 basename(const char *name)
762 const char *p = strrchr(name, '/');
763 return p != NULL ? p + 1 : name;
766 static struct utsname uts;
769 origin_subst_one(char *real, const char *kw, const char *subst,
772 char *p, *p1, *res, *resp;
773 int subst_len, kw_len, subst_count, old_len, new_len;
778 * First, count the number of the keyword occurences, to
779 * preallocate the final string.
781 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
788 * If the keyword is not found, just return.
790 if (subst_count == 0)
791 return (may_free ? real : xstrdup(real));
794 * There is indeed something to substitute. Calculate the
795 * length of the resulting string, and allocate it.
797 subst_len = strlen(subst);
798 old_len = strlen(real);
799 new_len = old_len + (subst_len - kw_len) * subst_count;
800 res = xmalloc(new_len + 1);
803 * Now, execute the substitution loop.
805 for (p = real, resp = res, *resp = '\0';;) {
808 /* Copy the prefix before keyword. */
809 memcpy(resp, p, p1 - p);
811 /* Keyword replacement. */
812 memcpy(resp, subst, subst_len);
820 /* Copy to the end of string and finish. */
828 origin_subst(char *real, const char *origin_path)
830 char *res1, *res2, *res3, *res4;
832 if (uts.sysname[0] == '\0') {
833 if (uname(&uts) != 0) {
834 _rtld_error("utsname failed: %d", errno);
838 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false);
839 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true);
840 res3 = origin_subst_one(res2, "$OSREL", uts.release, true);
841 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true);
848 const char *msg = dlerror();
852 rtld_fdputstr(STDERR_FILENO, msg);
853 rtld_fdputchar(STDERR_FILENO, '\n');
858 * Process a shared object's DYNAMIC section, and save the important
859 * information in its Obj_Entry structure.
862 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
863 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
866 Needed_Entry **needed_tail = &obj->needed;
867 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
868 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
869 const Elf_Hashelt *hashtab;
870 const Elf32_Word *hashval;
871 Elf32_Word bkt, nmaskwords;
874 int plttype = DT_REL;
880 obj->bind_now = false;
881 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
882 switch (dynp->d_tag) {
885 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
889 obj->relsize = dynp->d_un.d_val;
893 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
897 obj->pltrel = (const Elf_Rel *)
898 (obj->relocbase + dynp->d_un.d_ptr);
902 obj->pltrelsize = dynp->d_un.d_val;
906 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
910 obj->relasize = dynp->d_un.d_val;
914 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
918 plttype = dynp->d_un.d_val;
919 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
923 obj->symtab = (const Elf_Sym *)
924 (obj->relocbase + dynp->d_un.d_ptr);
928 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
932 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
936 obj->strsize = dynp->d_un.d_val;
940 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
945 obj->verneednum = dynp->d_un.d_val;
949 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
954 obj->verdefnum = dynp->d_un.d_val;
958 obj->versyms = (const Elf_Versym *)(obj->relocbase +
964 hashtab = (const Elf_Hashelt *)(obj->relocbase +
966 obj->nbuckets = hashtab[0];
967 obj->nchains = hashtab[1];
968 obj->buckets = hashtab + 2;
969 obj->chains = obj->buckets + obj->nbuckets;
970 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
971 obj->buckets != NULL;
977 hashtab = (const Elf_Hashelt *)(obj->relocbase +
979 obj->nbuckets_gnu = hashtab[0];
980 obj->symndx_gnu = hashtab[1];
981 nmaskwords = hashtab[2];
982 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
983 /* Number of bitmask words is required to be power of 2 */
984 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0);
985 obj->maskwords_bm_gnu = nmaskwords - 1;
986 obj->shift2_gnu = hashtab[3];
987 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
988 obj->buckets_gnu = hashtab + 4 + bloom_size32;
989 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
991 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 &&
992 obj->buckets_gnu != NULL;
998 Needed_Entry *nep = NEW(Needed_Entry);
999 nep->name = dynp->d_un.d_val;
1004 needed_tail = &nep->next;
1010 Needed_Entry *nep = NEW(Needed_Entry);
1011 nep->name = dynp->d_un.d_val;
1015 *needed_filtees_tail = nep;
1016 needed_filtees_tail = &nep->next;
1022 Needed_Entry *nep = NEW(Needed_Entry);
1023 nep->name = dynp->d_un.d_val;
1027 *needed_aux_filtees_tail = nep;
1028 needed_aux_filtees_tail = &nep->next;
1033 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1037 obj->textrel = true;
1041 obj->symbolic = true;
1046 * We have to wait until later to process this, because we
1047 * might not have gotten the address of the string table yet.
1057 *dyn_runpath = dynp;
1061 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1064 case DT_PREINIT_ARRAY:
1065 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1068 case DT_PREINIT_ARRAYSZ:
1069 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1073 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1076 case DT_INIT_ARRAYSZ:
1077 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1081 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1085 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1088 case DT_FINI_ARRAYSZ:
1089 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1093 * Don't process DT_DEBUG on MIPS as the dynamic section
1094 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1099 /* XXX - not implemented yet */
1101 dbg("Filling in DT_DEBUG entry");
1102 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1107 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1108 obj->z_origin = true;
1109 if (dynp->d_un.d_val & DF_SYMBOLIC)
1110 obj->symbolic = true;
1111 if (dynp->d_un.d_val & DF_TEXTREL)
1112 obj->textrel = true;
1113 if (dynp->d_un.d_val & DF_BIND_NOW)
1114 obj->bind_now = true;
1115 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1119 case DT_MIPS_LOCAL_GOTNO:
1120 obj->local_gotno = dynp->d_un.d_val;
1123 case DT_MIPS_SYMTABNO:
1124 obj->symtabno = dynp->d_un.d_val;
1127 case DT_MIPS_GOTSYM:
1128 obj->gotsym = dynp->d_un.d_val;
1131 case DT_MIPS_RLD_MAP:
1132 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1137 if (dynp->d_un.d_val & DF_1_NOOPEN)
1138 obj->z_noopen = true;
1139 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1140 obj->z_origin = true;
1141 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1143 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1144 obj->bind_now = true;
1145 if (dynp->d_un.d_val & DF_1_NODELETE)
1146 obj->z_nodelete = true;
1147 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1148 obj->z_loadfltr = true;
1149 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1150 obj->z_interpose = true;
1151 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1152 obj->z_nodeflib = true;
1157 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1164 obj->traced = false;
1166 if (plttype == DT_RELA) {
1167 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1169 obj->pltrelasize = obj->pltrelsize;
1170 obj->pltrelsize = 0;
1173 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1174 if (obj->valid_hash_sysv)
1175 obj->dynsymcount = obj->nchains;
1176 else if (obj->valid_hash_gnu) {
1177 obj->dynsymcount = 0;
1178 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1179 if (obj->buckets_gnu[bkt] == 0)
1181 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1184 while ((*hashval++ & 1u) == 0);
1186 obj->dynsymcount += obj->symndx_gnu;
1191 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1192 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1195 if (obj->z_origin && obj->origin_path == NULL) {
1196 obj->origin_path = xmalloc(PATH_MAX);
1197 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1201 if (dyn_runpath != NULL) {
1202 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1204 obj->runpath = origin_subst(obj->runpath, obj->origin_path);
1206 else if (dyn_rpath != NULL) {
1207 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1209 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1212 if (dyn_soname != NULL)
1213 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1217 digest_dynamic(Obj_Entry *obj, int early)
1219 const Elf_Dyn *dyn_rpath;
1220 const Elf_Dyn *dyn_soname;
1221 const Elf_Dyn *dyn_runpath;
1223 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1224 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1228 * Process a shared object's program header. This is used only for the
1229 * main program, when the kernel has already loaded the main program
1230 * into memory before calling the dynamic linker. It creates and
1231 * returns an Obj_Entry structure.
1234 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1237 const Elf_Phdr *phlimit = phdr + phnum;
1239 Elf_Addr note_start, note_end;
1243 for (ph = phdr; ph < phlimit; ph++) {
1244 if (ph->p_type != PT_PHDR)
1248 obj->phsize = ph->p_memsz;
1249 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1253 obj->stack_flags = PF_X | PF_R | PF_W;
1255 for (ph = phdr; ph < phlimit; ph++) {
1256 switch (ph->p_type) {
1259 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1263 if (nsegs == 0) { /* First load segment */
1264 obj->vaddrbase = trunc_page(ph->p_vaddr);
1265 obj->mapbase = obj->vaddrbase + obj->relocbase;
1266 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1268 } else { /* Last load segment */
1269 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1276 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1281 obj->tlssize = ph->p_memsz;
1282 obj->tlsalign = ph->p_align;
1283 obj->tlsinitsize = ph->p_filesz;
1284 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1288 obj->stack_flags = ph->p_flags;
1292 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1293 obj->relro_size = round_page(ph->p_memsz);
1297 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1298 note_end = note_start + ph->p_filesz;
1299 digest_notes(obj, note_start, note_end);
1304 _rtld_error("%s: too few PT_LOAD segments", path);
1313 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1315 const Elf_Note *note;
1316 const char *note_name;
1319 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1320 note = (const Elf_Note *)((const char *)(note + 1) +
1321 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1322 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1323 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1324 note->n_descsz != sizeof(int32_t))
1326 if (note->n_type != ABI_NOTETYPE &&
1327 note->n_type != CRT_NOINIT_NOTETYPE)
1329 note_name = (const char *)(note + 1);
1330 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1331 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1333 switch (note->n_type) {
1335 /* FreeBSD osrel note */
1336 p = (uintptr_t)(note + 1);
1337 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1338 obj->osrel = *(const int32_t *)(p);
1339 dbg("note osrel %d", obj->osrel);
1341 case CRT_NOINIT_NOTETYPE:
1342 /* FreeBSD 'crt does not call init' note */
1343 obj->crt_no_init = true;
1344 dbg("note crt_no_init");
1351 dlcheck(void *handle)
1355 for (obj = obj_list; obj != NULL; obj = obj->next)
1356 if (obj == (Obj_Entry *) handle)
1359 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1360 _rtld_error("Invalid shared object handle %p", handle);
1367 * If the given object is already in the donelist, return true. Otherwise
1368 * add the object to the list and return false.
1371 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1375 for (i = 0; i < dlp->num_used; i++)
1376 if (dlp->objs[i] == obj)
1379 * Our donelist allocation should always be sufficient. But if
1380 * our threads locking isn't working properly, more shared objects
1381 * could have been loaded since we allocated the list. That should
1382 * never happen, but we'll handle it properly just in case it does.
1384 if (dlp->num_used < dlp->num_alloc)
1385 dlp->objs[dlp->num_used++] = obj;
1390 * Hash function for symbol table lookup. Don't even think about changing
1391 * this. It is specified by the System V ABI.
1394 elf_hash(const char *name)
1396 const unsigned char *p = (const unsigned char *) name;
1397 unsigned long h = 0;
1400 while (*p != '\0') {
1401 h = (h << 4) + *p++;
1402 if ((g = h & 0xf0000000) != 0)
1410 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1411 * unsigned in case it's implemented with a wider type.
1414 gnu_hash(const char *s)
1420 for (c = *s; c != '\0'; c = *++s)
1422 return (h & 0xffffffff);
1427 * Find the library with the given name, and return its full pathname.
1428 * The returned string is dynamically allocated. Generates an error
1429 * message and returns NULL if the library cannot be found.
1431 * If the second argument is non-NULL, then it refers to an already-
1432 * loaded shared object, whose library search path will be searched.
1434 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1435 * descriptor (which is close-on-exec) will be passed out via the third
1438 * The search order is:
1439 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1440 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1442 * DT_RUNPATH in the referencing file
1443 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1445 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1447 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1450 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1454 bool nodeflib, objgiven;
1456 objgiven = refobj != NULL;
1457 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1458 if (xname[0] != '/' && !trust) {
1459 _rtld_error("Absolute pathname required for shared object \"%s\"",
1463 if (objgiven && refobj->z_origin) {
1464 return (origin_subst(__DECONST(char *, xname),
1465 refobj->origin_path));
1467 return (xstrdup(xname));
1471 if (libmap_disable || !objgiven ||
1472 (name = lm_find(refobj->path, xname)) == NULL)
1473 name = (char *)xname;
1475 dbg(" Searching for \"%s\"", name);
1478 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1479 * back to pre-conforming behaviour if user requested so with
1480 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1483 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1484 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1486 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1487 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL ||
1488 (pathname = search_library_path(name, gethints(false))) != NULL ||
1489 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1492 nodeflib = objgiven ? refobj->z_nodeflib : false;
1494 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1495 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1496 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1497 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1499 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1500 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL ||
1501 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1502 (objgiven && !nodeflib &&
1503 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1507 if (objgiven && refobj->path != NULL) {
1508 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1509 name, basename(refobj->path));
1511 _rtld_error("Shared object \"%s\" not found", name);
1517 * Given a symbol number in a referencing object, find the corresponding
1518 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1519 * no definition was found. Returns a pointer to the Obj_Entry of the
1520 * defining object via the reference parameter DEFOBJ_OUT.
1523 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1524 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1525 RtldLockState *lockstate)
1529 const Obj_Entry *defobj;
1535 * If we have already found this symbol, get the information from
1538 if (symnum >= refobj->dynsymcount)
1539 return NULL; /* Bad object */
1540 if (cache != NULL && cache[symnum].sym != NULL) {
1541 *defobj_out = cache[symnum].obj;
1542 return cache[symnum].sym;
1545 ref = refobj->symtab + symnum;
1546 name = refobj->strtab + ref->st_name;
1551 * We don't have to do a full scale lookup if the symbol is local.
1552 * We know it will bind to the instance in this load module; to
1553 * which we already have a pointer (ie ref). By not doing a lookup,
1554 * we not only improve performance, but it also avoids unresolvable
1555 * symbols when local symbols are not in the hash table. This has
1556 * been seen with the ia64 toolchain.
1558 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1559 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1560 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1563 symlook_init(&req, name);
1565 req.ventry = fetch_ventry(refobj, symnum);
1566 req.lockstate = lockstate;
1567 res = symlook_default(&req, refobj);
1570 defobj = req.defobj_out;
1578 * If we found no definition and the reference is weak, treat the
1579 * symbol as having the value zero.
1581 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1587 *defobj_out = defobj;
1588 /* Record the information in the cache to avoid subsequent lookups. */
1589 if (cache != NULL) {
1590 cache[symnum].sym = def;
1591 cache[symnum].obj = defobj;
1594 if (refobj != &obj_rtld)
1595 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1601 * Return the search path from the ldconfig hints file, reading it if
1602 * necessary. If nostdlib is true, then the default search paths are
1603 * not added to result.
1605 * Returns NULL if there are problems with the hints file,
1606 * or if the search path there is empty.
1609 gethints(bool nostdlib)
1611 static char *hints, *filtered_path;
1612 struct elfhints_hdr hdr;
1613 struct fill_search_info_args sargs, hargs;
1614 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1615 struct dl_serpath *SLPpath, *hintpath;
1617 unsigned int SLPndx, hintndx, fndx, fcount;
1622 /* First call, read the hints file */
1623 if (hints == NULL) {
1624 /* Keep from trying again in case the hints file is bad. */
1627 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1629 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1630 hdr.magic != ELFHINTS_MAGIC ||
1635 p = xmalloc(hdr.dirlistlen + 1);
1636 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1637 read(fd, p, hdr.dirlistlen + 1) !=
1638 (ssize_t)hdr.dirlistlen + 1) {
1648 * If caller agreed to receive list which includes the default
1649 * paths, we are done. Otherwise, if we still did not
1650 * calculated filtered result, do it now.
1653 return (hints[0] != '\0' ? hints : NULL);
1654 if (filtered_path != NULL)
1658 * Obtain the list of all configured search paths, and the
1659 * list of the default paths.
1661 * First estimate the size of the results.
1663 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1665 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1668 sargs.request = RTLD_DI_SERINFOSIZE;
1669 sargs.serinfo = &smeta;
1670 hargs.request = RTLD_DI_SERINFOSIZE;
1671 hargs.serinfo = &hmeta;
1673 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1674 path_enumerate(p, fill_search_info, &hargs);
1676 SLPinfo = xmalloc(smeta.dls_size);
1677 hintinfo = xmalloc(hmeta.dls_size);
1680 * Next fetch both sets of paths.
1682 sargs.request = RTLD_DI_SERINFO;
1683 sargs.serinfo = SLPinfo;
1684 sargs.serpath = &SLPinfo->dls_serpath[0];
1685 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1687 hargs.request = RTLD_DI_SERINFO;
1688 hargs.serinfo = hintinfo;
1689 hargs.serpath = &hintinfo->dls_serpath[0];
1690 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1692 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1693 path_enumerate(p, fill_search_info, &hargs);
1696 * Now calculate the difference between two sets, by excluding
1697 * standard paths from the full set.
1701 filtered_path = xmalloc(hdr.dirlistlen + 1);
1702 hintpath = &hintinfo->dls_serpath[0];
1703 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1705 SLPpath = &SLPinfo->dls_serpath[0];
1707 * Check each standard path against current.
1709 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1710 /* matched, skip the path */
1711 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1719 * Not matched against any standard path, add the path
1720 * to result. Separate consequtive paths with ':'.
1723 filtered_path[fndx] = ':';
1727 flen = strlen(hintpath->dls_name);
1728 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1731 filtered_path[fndx] = '\0';
1737 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1741 init_dag(Obj_Entry *root)
1743 const Needed_Entry *needed;
1744 const Objlist_Entry *elm;
1747 if (root->dag_inited)
1749 donelist_init(&donelist);
1751 /* Root object belongs to own DAG. */
1752 objlist_push_tail(&root->dldags, root);
1753 objlist_push_tail(&root->dagmembers, root);
1754 donelist_check(&donelist, root);
1757 * Add dependencies of root object to DAG in breadth order
1758 * by exploiting the fact that each new object get added
1759 * to the tail of the dagmembers list.
1761 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1762 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1763 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1765 objlist_push_tail(&needed->obj->dldags, root);
1766 objlist_push_tail(&root->dagmembers, needed->obj);
1769 root->dag_inited = true;
1773 process_nodelete(Obj_Entry *root)
1775 const Objlist_Entry *elm;
1778 * Walk over object DAG and process every dependent object that
1779 * is marked as DF_1_NODELETE. They need to grow their own DAG,
1780 * which then should have its reference upped separately.
1782 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1783 if (elm->obj != NULL && elm->obj->z_nodelete &&
1784 !elm->obj->ref_nodel) {
1785 dbg("obj %s nodelete", elm->obj->path);
1788 elm->obj->ref_nodel = true;
1793 * Initialize the dynamic linker. The argument is the address at which
1794 * the dynamic linker has been mapped into memory. The primary task of
1795 * this function is to relocate the dynamic linker.
1798 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1800 Obj_Entry objtmp; /* Temporary rtld object */
1801 const Elf_Dyn *dyn_rpath;
1802 const Elf_Dyn *dyn_soname;
1803 const Elf_Dyn *dyn_runpath;
1805 #ifdef RTLD_INIT_PAGESIZES_EARLY
1806 /* The page size is required by the dynamic memory allocator. */
1807 init_pagesizes(aux_info);
1811 * Conjure up an Obj_Entry structure for the dynamic linker.
1813 * The "path" member can't be initialized yet because string constants
1814 * cannot yet be accessed. Below we will set it correctly.
1816 memset(&objtmp, 0, sizeof(objtmp));
1819 objtmp.mapbase = mapbase;
1821 objtmp.relocbase = mapbase;
1823 if (RTLD_IS_DYNAMIC()) {
1824 objtmp.dynamic = rtld_dynamic(&objtmp);
1825 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1826 assert(objtmp.needed == NULL);
1827 #if !defined(__mips__)
1828 /* MIPS has a bogus DT_TEXTREL. */
1829 assert(!objtmp.textrel);
1833 * Temporarily put the dynamic linker entry into the object list, so
1834 * that symbols can be found.
1837 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1840 /* Initialize the object list. */
1841 obj_tail = &obj_list;
1843 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1844 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1846 #ifndef RTLD_INIT_PAGESIZES_EARLY
1847 /* The page size is required by the dynamic memory allocator. */
1848 init_pagesizes(aux_info);
1851 if (aux_info[AT_OSRELDATE] != NULL)
1852 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1854 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1856 /* Replace the path with a dynamically allocated copy. */
1857 obj_rtld.path = xstrdup(PATH_RTLD);
1859 r_debug.r_brk = r_debug_state;
1860 r_debug.r_state = RT_CONSISTENT;
1864 * Retrieve the array of supported page sizes. The kernel provides the page
1865 * sizes in increasing order.
1868 init_pagesizes(Elf_Auxinfo **aux_info)
1870 static size_t psa[MAXPAGESIZES];
1874 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
1876 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
1877 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
1880 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
1883 /* As a fallback, retrieve the base page size. */
1884 size = sizeof(psa[0]);
1885 if (aux_info[AT_PAGESZ] != NULL) {
1886 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
1890 mib[1] = HW_PAGESIZE;
1894 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
1895 _rtld_error("sysctl for hw.pagesize(s) failed");
1901 npagesizes = size / sizeof(pagesizes[0]);
1902 /* Discard any invalid entries at the end of the array. */
1903 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
1908 * Add the init functions from a needed object list (and its recursive
1909 * needed objects) to "list". This is not used directly; it is a helper
1910 * function for initlist_add_objects(). The write lock must be held
1911 * when this function is called.
1914 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1916 /* Recursively process the successor needed objects. */
1917 if (needed->next != NULL)
1918 initlist_add_neededs(needed->next, list);
1920 /* Process the current needed object. */
1921 if (needed->obj != NULL)
1922 initlist_add_objects(needed->obj, &needed->obj->next, list);
1926 * Scan all of the DAGs rooted in the range of objects from "obj" to
1927 * "tail" and add their init functions to "list". This recurses over
1928 * the DAGs and ensure the proper init ordering such that each object's
1929 * needed libraries are initialized before the object itself. At the
1930 * same time, this function adds the objects to the global finalization
1931 * list "list_fini" in the opposite order. The write lock must be
1932 * held when this function is called.
1935 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1938 if (obj->init_scanned || obj->init_done)
1940 obj->init_scanned = true;
1942 /* Recursively process the successor objects. */
1943 if (&obj->next != tail)
1944 initlist_add_objects(obj->next, tail, list);
1946 /* Recursively process the needed objects. */
1947 if (obj->needed != NULL)
1948 initlist_add_neededs(obj->needed, list);
1949 if (obj->needed_filtees != NULL)
1950 initlist_add_neededs(obj->needed_filtees, list);
1951 if (obj->needed_aux_filtees != NULL)
1952 initlist_add_neededs(obj->needed_aux_filtees, list);
1954 /* Add the object to the init list. */
1955 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1956 obj->init_array != (Elf_Addr)NULL)
1957 objlist_push_tail(list, obj);
1959 /* Add the object to the global fini list in the reverse order. */
1960 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1961 && !obj->on_fini_list) {
1962 objlist_push_head(&list_fini, obj);
1963 obj->on_fini_list = true;
1968 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1972 free_needed_filtees(Needed_Entry *n)
1974 Needed_Entry *needed, *needed1;
1976 for (needed = n; needed != NULL; needed = needed->next) {
1977 if (needed->obj != NULL) {
1978 dlclose(needed->obj);
1982 for (needed = n; needed != NULL; needed = needed1) {
1983 needed1 = needed->next;
1989 unload_filtees(Obj_Entry *obj)
1992 free_needed_filtees(obj->needed_filtees);
1993 obj->needed_filtees = NULL;
1994 free_needed_filtees(obj->needed_aux_filtees);
1995 obj->needed_aux_filtees = NULL;
1996 obj->filtees_loaded = false;
2000 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2001 RtldLockState *lockstate)
2004 for (; needed != NULL; needed = needed->next) {
2005 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2006 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2007 RTLD_LOCAL, lockstate);
2012 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2015 lock_restart_for_upgrade(lockstate);
2016 if (!obj->filtees_loaded) {
2017 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2018 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2019 obj->filtees_loaded = true;
2024 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2028 for (; needed != NULL; needed = needed->next) {
2029 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2030 flags & ~RTLD_LO_NOLOAD);
2031 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2038 * Given a shared object, traverse its list of needed objects, and load
2039 * each of them. Returns 0 on success. Generates an error message and
2040 * returns -1 on failure.
2043 load_needed_objects(Obj_Entry *first, int flags)
2047 for (obj = first; obj != NULL; obj = obj->next) {
2048 if (process_needed(obj, obj->needed, flags) == -1)
2055 load_preload_objects(void)
2057 char *p = ld_preload;
2059 static const char delim[] = " \t:;";
2064 p += strspn(p, delim);
2065 while (*p != '\0') {
2066 size_t len = strcspn(p, delim);
2071 obj = load_object(p, -1, NULL, 0);
2073 return -1; /* XXX - cleanup */
2074 obj->z_interpose = true;
2077 p += strspn(p, delim);
2079 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2084 printable_path(const char *path)
2087 return (path == NULL ? "<unknown>" : path);
2091 * Load a shared object into memory, if it is not already loaded. The
2092 * object may be specified by name or by user-supplied file descriptor
2093 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2096 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2100 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2109 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2110 if (object_match_name(obj, name))
2114 path = find_library(name, refobj, &fd);
2122 * search_library_pathfds() opens a fresh file descriptor for the
2123 * library, so there is no need to dup().
2125 } else if (fd_u == -1) {
2127 * If we didn't find a match by pathname, or the name is not
2128 * supplied, open the file and check again by device and inode.
2129 * This avoids false mismatches caused by multiple links or ".."
2132 * To avoid a race, we open the file and use fstat() rather than
2135 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) {
2136 _rtld_error("Cannot open \"%s\"", path);
2141 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2143 _rtld_error("Cannot dup fd");
2148 if (fstat(fd, &sb) == -1) {
2149 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2154 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2155 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2157 if (obj != NULL && name != NULL) {
2158 object_add_name(obj, name);
2163 if (flags & RTLD_LO_NOLOAD) {
2169 /* First use of this object, so we must map it in */
2170 obj = do_load_object(fd, name, path, &sb, flags);
2179 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2186 * but first, make sure that environment variables haven't been
2187 * used to circumvent the noexec flag on a filesystem.
2189 if (dangerous_ld_env) {
2190 if (fstatfs(fd, &fs) != 0) {
2191 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2194 if (fs.f_flags & MNT_NOEXEC) {
2195 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2199 dbg("loading \"%s\"", printable_path(path));
2200 obj = map_object(fd, printable_path(path), sbp);
2205 * If DT_SONAME is present in the object, digest_dynamic2 already
2206 * added it to the object names.
2209 object_add_name(obj, name);
2211 digest_dynamic(obj, 0);
2212 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2213 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2214 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2216 dbg("refusing to load non-loadable \"%s\"", obj->path);
2217 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2218 munmap(obj->mapbase, obj->mapsize);
2224 obj_tail = &obj->next;
2227 linkmap_add(obj); /* for GDB & dlinfo() */
2228 max_stack_flags |= obj->stack_flags;
2230 dbg(" %p .. %p: %s", obj->mapbase,
2231 obj->mapbase + obj->mapsize - 1, obj->path);
2233 dbg(" WARNING: %s has impure text", obj->path);
2234 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2241 obj_from_addr(const void *addr)
2245 for (obj = obj_list; obj != NULL; obj = obj->next) {
2246 if (addr < (void *) obj->mapbase)
2248 if (addr < (void *) (obj->mapbase + obj->mapsize))
2257 Elf_Addr *preinit_addr;
2260 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2261 if (preinit_addr == NULL)
2264 for (index = 0; index < obj_main->preinit_array_num; index++) {
2265 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2266 dbg("calling preinit function for %s at %p", obj_main->path,
2267 (void *)preinit_addr[index]);
2268 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2269 0, 0, obj_main->path);
2270 call_init_pointer(obj_main, preinit_addr[index]);
2276 * Call the finalization functions for each of the objects in "list"
2277 * belonging to the DAG of "root" and referenced once. If NULL "root"
2278 * is specified, every finalization function will be called regardless
2279 * of the reference count and the list elements won't be freed. All of
2280 * the objects are expected to have non-NULL fini functions.
2283 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2287 Elf_Addr *fini_addr;
2290 assert(root == NULL || root->refcount == 1);
2293 * Preserve the current error message since a fini function might
2294 * call into the dynamic linker and overwrite it.
2296 saved_msg = errmsg_save();
2298 STAILQ_FOREACH(elm, list, link) {
2299 if (root != NULL && (elm->obj->refcount != 1 ||
2300 objlist_find(&root->dagmembers, elm->obj) == NULL))
2302 /* Remove object from fini list to prevent recursive invocation. */
2303 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2305 * XXX: If a dlopen() call references an object while the
2306 * fini function is in progress, we might end up trying to
2307 * unload the referenced object in dlclose() or the object
2308 * won't be unloaded although its fini function has been
2311 lock_release(rtld_bind_lock, lockstate);
2314 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2315 * When this happens, DT_FINI_ARRAY is processed first.
2317 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2318 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2319 for (index = elm->obj->fini_array_num - 1; index >= 0;
2321 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2322 dbg("calling fini function for %s at %p",
2323 elm->obj->path, (void *)fini_addr[index]);
2324 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2325 (void *)fini_addr[index], 0, 0, elm->obj->path);
2326 call_initfini_pointer(elm->obj, fini_addr[index]);
2330 if (elm->obj->fini != (Elf_Addr)NULL) {
2331 dbg("calling fini function for %s at %p", elm->obj->path,
2332 (void *)elm->obj->fini);
2333 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2334 0, 0, elm->obj->path);
2335 call_initfini_pointer(elm->obj, elm->obj->fini);
2337 wlock_acquire(rtld_bind_lock, lockstate);
2338 /* No need to free anything if process is going down. */
2342 * We must restart the list traversal after every fini call
2343 * because a dlclose() call from the fini function or from
2344 * another thread might have modified the reference counts.
2348 } while (elm != NULL);
2349 errmsg_restore(saved_msg);
2353 * Call the initialization functions for each of the objects in
2354 * "list". All of the objects are expected to have non-NULL init
2358 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2363 Elf_Addr *init_addr;
2367 * Clean init_scanned flag so that objects can be rechecked and
2368 * possibly initialized earlier if any of vectors called below
2369 * cause the change by using dlopen.
2371 for (obj = obj_list; obj != NULL; obj = obj->next)
2372 obj->init_scanned = false;
2375 * Preserve the current error message since an init function might
2376 * call into the dynamic linker and overwrite it.
2378 saved_msg = errmsg_save();
2379 STAILQ_FOREACH(elm, list, link) {
2380 if (elm->obj->init_done) /* Initialized early. */
2383 * Race: other thread might try to use this object before current
2384 * one completes the initilization. Not much can be done here
2385 * without better locking.
2387 elm->obj->init_done = true;
2388 lock_release(rtld_bind_lock, lockstate);
2391 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2392 * When this happens, DT_INIT is processed first.
2394 if (elm->obj->init != (Elf_Addr)NULL) {
2395 dbg("calling init function for %s at %p", elm->obj->path,
2396 (void *)elm->obj->init);
2397 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2398 0, 0, elm->obj->path);
2399 call_initfini_pointer(elm->obj, elm->obj->init);
2401 init_addr = (Elf_Addr *)elm->obj->init_array;
2402 if (init_addr != NULL) {
2403 for (index = 0; index < elm->obj->init_array_num; index++) {
2404 if (init_addr[index] != 0 && init_addr[index] != 1) {
2405 dbg("calling init function for %s at %p", elm->obj->path,
2406 (void *)init_addr[index]);
2407 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2408 (void *)init_addr[index], 0, 0, elm->obj->path);
2409 call_init_pointer(elm->obj, init_addr[index]);
2413 wlock_acquire(rtld_bind_lock, lockstate);
2415 errmsg_restore(saved_msg);
2419 objlist_clear(Objlist *list)
2423 while (!STAILQ_EMPTY(list)) {
2424 elm = STAILQ_FIRST(list);
2425 STAILQ_REMOVE_HEAD(list, link);
2430 static Objlist_Entry *
2431 objlist_find(Objlist *list, const Obj_Entry *obj)
2435 STAILQ_FOREACH(elm, list, link)
2436 if (elm->obj == obj)
2442 objlist_init(Objlist *list)
2448 objlist_push_head(Objlist *list, Obj_Entry *obj)
2452 elm = NEW(Objlist_Entry);
2454 STAILQ_INSERT_HEAD(list, elm, link);
2458 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2462 elm = NEW(Objlist_Entry);
2464 STAILQ_INSERT_TAIL(list, elm, link);
2468 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2470 Objlist_Entry *elm, *listelm;
2472 STAILQ_FOREACH(listelm, list, link) {
2473 if (listelm->obj == listobj)
2476 elm = NEW(Objlist_Entry);
2478 if (listelm != NULL)
2479 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2481 STAILQ_INSERT_TAIL(list, elm, link);
2485 objlist_remove(Objlist *list, Obj_Entry *obj)
2489 if ((elm = objlist_find(list, obj)) != NULL) {
2490 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2496 * Relocate dag rooted in the specified object.
2497 * Returns 0 on success, or -1 on failure.
2501 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2502 int flags, RtldLockState *lockstate)
2508 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2509 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2518 * Relocate single object.
2519 * Returns 0 on success, or -1 on failure.
2522 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2523 int flags, RtldLockState *lockstate)
2528 obj->relocated = true;
2530 dbg("relocating \"%s\"", obj->path);
2532 if (obj->symtab == NULL || obj->strtab == NULL ||
2533 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2534 _rtld_error("%s: Shared object has no run-time symbol table",
2540 /* There are relocations to the write-protected text segment. */
2541 if (mprotect(obj->mapbase, obj->textsize,
2542 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2543 _rtld_error("%s: Cannot write-enable text segment: %s",
2544 obj->path, rtld_strerror(errno));
2549 /* Process the non-PLT relocations. */
2550 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2553 if (obj->textrel) { /* Re-protected the text segment. */
2554 if (mprotect(obj->mapbase, obj->textsize,
2555 PROT_READ|PROT_EXEC) == -1) {
2556 _rtld_error("%s: Cannot write-protect text segment: %s",
2557 obj->path, rtld_strerror(errno));
2563 /* Set the special PLT or GOT entries. */
2566 /* Process the PLT relocations. */
2567 if (reloc_plt(obj) == -1)
2569 /* Relocate the jump slots if we are doing immediate binding. */
2570 if (obj->bind_now || bind_now)
2571 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2574 if (obj->relro_size > 0) {
2575 if (mprotect(obj->relro_page, obj->relro_size,
2577 _rtld_error("%s: Cannot enforce relro protection: %s",
2578 obj->path, rtld_strerror(errno));
2584 * Set up the magic number and version in the Obj_Entry. These
2585 * were checked in the crt1.o from the original ElfKit, so we
2586 * set them for backward compatibility.
2588 obj->magic = RTLD_MAGIC;
2589 obj->version = RTLD_VERSION;
2595 * Relocate newly-loaded shared objects. The argument is a pointer to
2596 * the Obj_Entry for the first such object. All objects from the first
2597 * to the end of the list of objects are relocated. Returns 0 on success,
2601 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2602 int flags, RtldLockState *lockstate)
2607 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2608 error = relocate_object(obj, bind_now, rtldobj, flags,
2617 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2618 * referencing STT_GNU_IFUNC symbols is postponed till the other
2619 * relocations are done. The indirect functions specified as
2620 * ifunc are allowed to call other symbols, so we need to have
2621 * objects relocated before asking for resolution from indirects.
2623 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2624 * instead of the usual lazy handling of PLT slots. It is
2625 * consistent with how GNU does it.
2628 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2629 RtldLockState *lockstate)
2631 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2633 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2634 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2640 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2641 RtldLockState *lockstate)
2645 for (obj = first; obj != NULL; obj = obj->next) {
2646 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2653 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2654 RtldLockState *lockstate)
2658 STAILQ_FOREACH(elm, list, link) {
2659 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2667 * Cleanup procedure. It will be called (by the atexit mechanism) just
2668 * before the process exits.
2673 RtldLockState lockstate;
2675 wlock_acquire(rtld_bind_lock, &lockstate);
2677 objlist_call_fini(&list_fini, NULL, &lockstate);
2678 /* No need to remove the items from the list, since we are exiting. */
2679 if (!libmap_disable)
2681 lock_release(rtld_bind_lock, &lockstate);
2685 * Iterate over a search path, translate each element, and invoke the
2686 * callback on the result.
2689 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2695 path += strspn(path, ":;");
2696 while (*path != '\0') {
2700 len = strcspn(path, ":;");
2701 trans = lm_findn(NULL, path, len);
2703 res = callback(trans, strlen(trans), arg);
2705 res = callback(path, len, arg);
2711 path += strspn(path, ":;");
2717 struct try_library_args {
2725 try_library_path(const char *dir, size_t dirlen, void *param)
2727 struct try_library_args *arg;
2730 if (*dir == '/' || trust) {
2733 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2736 pathname = arg->buffer;
2737 strncpy(pathname, dir, dirlen);
2738 pathname[dirlen] = '/';
2739 strcpy(pathname + dirlen + 1, arg->name);
2741 dbg(" Trying \"%s\"", pathname);
2742 if (access(pathname, F_OK) == 0) { /* We found it */
2743 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2744 strcpy(pathname, arg->buffer);
2752 search_library_path(const char *name, const char *path)
2755 struct try_library_args arg;
2761 arg.namelen = strlen(name);
2762 arg.buffer = xmalloc(PATH_MAX);
2763 arg.buflen = PATH_MAX;
2765 p = path_enumerate(path, try_library_path, &arg);
2774 * Finds the library with the given name using the directory descriptors
2775 * listed in the LD_LIBRARY_PATH_FDS environment variable.
2777 * Returns a freshly-opened close-on-exec file descriptor for the library,
2778 * or -1 if the library cannot be found.
2781 search_library_pathfds(const char *name, const char *path, int *fdp)
2783 char *envcopy, *fdstr, *found, *last_token;
2787 dbg("%s('%s', '%s', fdp)\n", __func__, name, path);
2789 /* Don't load from user-specified libdirs into setuid binaries. */
2793 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
2797 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
2798 if (name[0] == '/') {
2799 dbg("Absolute path (%s) passed to %s", name, __func__);
2804 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
2805 * copy of the path, as strtok_r rewrites separator tokens
2809 envcopy = xstrdup(path);
2810 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
2811 fdstr = strtok_r(NULL, ":", &last_token)) {
2812 dirfd = parse_libdir(fdstr);
2815 fd = openat(dirfd, name, O_RDONLY | O_CLOEXEC);
2818 len = strlen(fdstr) + strlen(name) + 3;
2819 found = xmalloc(len);
2820 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
2821 _rtld_error("error generating '%d/%s'",
2825 dbg("open('%s') => %d", found, fd);
2836 dlclose(void *handle)
2839 RtldLockState lockstate;
2841 wlock_acquire(rtld_bind_lock, &lockstate);
2842 root = dlcheck(handle);
2844 lock_release(rtld_bind_lock, &lockstate);
2847 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2850 /* Unreference the object and its dependencies. */
2851 root->dl_refcount--;
2853 if (root->refcount == 1) {
2855 * The object will be no longer referenced, so we must unload it.
2856 * First, call the fini functions.
2858 objlist_call_fini(&list_fini, root, &lockstate);
2862 /* Finish cleaning up the newly-unreferenced objects. */
2863 GDB_STATE(RT_DELETE,&root->linkmap);
2864 unload_object(root);
2865 GDB_STATE(RT_CONSISTENT,NULL);
2869 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2870 lock_release(rtld_bind_lock, &lockstate);
2877 char *msg = error_message;
2878 error_message = NULL;
2883 * This function is deprecated and has no effect.
2886 dllockinit(void *context,
2887 void *(*lock_create)(void *context),
2888 void (*rlock_acquire)(void *lock),
2889 void (*wlock_acquire)(void *lock),
2890 void (*lock_release)(void *lock),
2891 void (*lock_destroy)(void *lock),
2892 void (*context_destroy)(void *context))
2894 static void *cur_context;
2895 static void (*cur_context_destroy)(void *);
2897 /* Just destroy the context from the previous call, if necessary. */
2898 if (cur_context_destroy != NULL)
2899 cur_context_destroy(cur_context);
2900 cur_context = context;
2901 cur_context_destroy = context_destroy;
2905 dlopen(const char *name, int mode)
2908 return (rtld_dlopen(name, -1, mode));
2912 fdlopen(int fd, int mode)
2915 return (rtld_dlopen(NULL, fd, mode));
2919 rtld_dlopen(const char *name, int fd, int mode)
2921 RtldLockState lockstate;
2924 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2925 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2926 if (ld_tracing != NULL) {
2927 rlock_acquire(rtld_bind_lock, &lockstate);
2928 if (sigsetjmp(lockstate.env, 0) != 0)
2929 lock_upgrade(rtld_bind_lock, &lockstate);
2930 environ = (char **)*get_program_var_addr("environ", &lockstate);
2931 lock_release(rtld_bind_lock, &lockstate);
2933 lo_flags = RTLD_LO_DLOPEN;
2934 if (mode & RTLD_NODELETE)
2935 lo_flags |= RTLD_LO_NODELETE;
2936 if (mode & RTLD_NOLOAD)
2937 lo_flags |= RTLD_LO_NOLOAD;
2938 if (ld_tracing != NULL)
2939 lo_flags |= RTLD_LO_TRACE;
2941 return (dlopen_object(name, fd, obj_main, lo_flags,
2942 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
2946 dlopen_cleanup(Obj_Entry *obj)
2951 if (obj->refcount == 0)
2956 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2957 int mode, RtldLockState *lockstate)
2959 Obj_Entry **old_obj_tail;
2962 RtldLockState mlockstate;
2965 objlist_init(&initlist);
2967 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
2968 wlock_acquire(rtld_bind_lock, &mlockstate);
2969 lockstate = &mlockstate;
2971 GDB_STATE(RT_ADD,NULL);
2973 old_obj_tail = obj_tail;
2975 if (name == NULL && fd == -1) {
2979 obj = load_object(name, fd, refobj, lo_flags);
2984 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2985 objlist_push_tail(&list_global, obj);
2986 if (*old_obj_tail != NULL) { /* We loaded something new. */
2987 assert(*old_obj_tail == obj);
2988 result = load_needed_objects(obj,
2989 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
2993 result = rtld_verify_versions(&obj->dagmembers);
2994 if (result != -1 && ld_tracing)
2996 if (result == -1 || relocate_object_dag(obj,
2997 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
2998 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3000 dlopen_cleanup(obj);
3002 } else if (lo_flags & RTLD_LO_EARLY) {
3004 * Do not call the init functions for early loaded
3005 * filtees. The image is still not initialized enough
3008 * Our object is found by the global object list and
3009 * will be ordered among all init calls done right
3010 * before transferring control to main.
3013 /* Make list of init functions to call. */
3014 initlist_add_objects(obj, &obj->next, &initlist);
3017 * Process all no_delete objects here, given them own
3018 * DAGs to prevent their dependencies from being unloaded.
3019 * This has to be done after we have loaded all of the
3020 * dependencies, so that we do not miss any.
3023 process_nodelete(obj);
3026 * Bump the reference counts for objects on this DAG. If
3027 * this is the first dlopen() call for the object that was
3028 * already loaded as a dependency, initialize the dag
3034 if ((lo_flags & RTLD_LO_TRACE) != 0)
3037 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3038 obj->z_nodelete) && !obj->ref_nodel) {
3039 dbg("obj %s nodelete", obj->path);
3041 obj->z_nodelete = obj->ref_nodel = true;
3045 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3047 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3049 if (!(lo_flags & RTLD_LO_EARLY)) {
3050 map_stacks_exec(lockstate);
3053 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3054 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3056 objlist_clear(&initlist);
3057 dlopen_cleanup(obj);
3058 if (lockstate == &mlockstate)
3059 lock_release(rtld_bind_lock, lockstate);
3063 if (!(lo_flags & RTLD_LO_EARLY)) {
3064 /* Call the init functions. */
3065 objlist_call_init(&initlist, lockstate);
3067 objlist_clear(&initlist);
3068 if (lockstate == &mlockstate)
3069 lock_release(rtld_bind_lock, lockstate);
3072 trace_loaded_objects(obj);
3073 if (lockstate == &mlockstate)
3074 lock_release(rtld_bind_lock, lockstate);
3079 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3083 const Obj_Entry *obj, *defobj;
3086 RtldLockState lockstate;
3092 symlook_init(&req, name);
3094 req.flags = flags | SYMLOOK_IN_PLT;
3095 req.lockstate = &lockstate;
3097 rlock_acquire(rtld_bind_lock, &lockstate);
3098 if (sigsetjmp(lockstate.env, 0) != 0)
3099 lock_upgrade(rtld_bind_lock, &lockstate);
3100 if (handle == NULL || handle == RTLD_NEXT ||
3101 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3103 if ((obj = obj_from_addr(retaddr)) == NULL) {
3104 _rtld_error("Cannot determine caller's shared object");
3105 lock_release(rtld_bind_lock, &lockstate);
3108 if (handle == NULL) { /* Just the caller's shared object. */
3109 res = symlook_obj(&req, obj);
3112 defobj = req.defobj_out;
3114 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3115 handle == RTLD_SELF) { /* ... caller included */
3116 if (handle == RTLD_NEXT)
3118 for (; obj != NULL; obj = obj->next) {
3119 res = symlook_obj(&req, obj);
3122 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3124 defobj = req.defobj_out;
3125 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3131 * Search the dynamic linker itself, and possibly resolve the
3132 * symbol from there. This is how the application links to
3133 * dynamic linker services such as dlopen.
3135 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3136 res = symlook_obj(&req, &obj_rtld);
3139 defobj = req.defobj_out;
3143 assert(handle == RTLD_DEFAULT);
3144 res = symlook_default(&req, obj);
3146 defobj = req.defobj_out;
3151 if ((obj = dlcheck(handle)) == NULL) {
3152 lock_release(rtld_bind_lock, &lockstate);
3156 donelist_init(&donelist);
3157 if (obj->mainprog) {
3158 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3159 res = symlook_global(&req, &donelist);
3162 defobj = req.defobj_out;
3165 * Search the dynamic linker itself, and possibly resolve the
3166 * symbol from there. This is how the application links to
3167 * dynamic linker services such as dlopen.
3169 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3170 res = symlook_obj(&req, &obj_rtld);
3173 defobj = req.defobj_out;
3178 /* Search the whole DAG rooted at the given object. */
3179 res = symlook_list(&req, &obj->dagmembers, &donelist);
3182 defobj = req.defobj_out;
3188 lock_release(rtld_bind_lock, &lockstate);
3191 * The value required by the caller is derived from the value
3192 * of the symbol. this is simply the relocated value of the
3195 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3196 return (make_function_pointer(def, defobj));
3197 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3198 return (rtld_resolve_ifunc(defobj, def));
3199 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3200 ti.ti_module = defobj->tlsindex;
3201 ti.ti_offset = def->st_value;
3202 return (__tls_get_addr(&ti));
3204 return (defobj->relocbase + def->st_value);
3207 _rtld_error("Undefined symbol \"%s\"", name);
3208 lock_release(rtld_bind_lock, &lockstate);
3213 dlsym(void *handle, const char *name)
3215 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3220 dlfunc(void *handle, const char *name)
3227 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3233 dlvsym(void *handle, const char *name, const char *version)
3237 ventry.name = version;
3239 ventry.hash = elf_hash(version);
3241 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3246 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3248 const Obj_Entry *obj;
3249 RtldLockState lockstate;
3251 rlock_acquire(rtld_bind_lock, &lockstate);
3252 obj = obj_from_addr(addr);
3254 _rtld_error("No shared object contains address");
3255 lock_release(rtld_bind_lock, &lockstate);
3258 rtld_fill_dl_phdr_info(obj, phdr_info);
3259 lock_release(rtld_bind_lock, &lockstate);
3264 dladdr(const void *addr, Dl_info *info)
3266 const Obj_Entry *obj;
3269 unsigned long symoffset;
3270 RtldLockState lockstate;
3272 rlock_acquire(rtld_bind_lock, &lockstate);
3273 obj = obj_from_addr(addr);
3275 _rtld_error("No shared object contains address");
3276 lock_release(rtld_bind_lock, &lockstate);
3279 info->dli_fname = obj->path;
3280 info->dli_fbase = obj->mapbase;
3281 info->dli_saddr = (void *)0;
3282 info->dli_sname = NULL;
3285 * Walk the symbol list looking for the symbol whose address is
3286 * closest to the address sent in.
3288 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3289 def = obj->symtab + symoffset;
3292 * For skip the symbol if st_shndx is either SHN_UNDEF or
3295 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3299 * If the symbol is greater than the specified address, or if it
3300 * is further away from addr than the current nearest symbol,
3303 symbol_addr = obj->relocbase + def->st_value;
3304 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3307 /* Update our idea of the nearest symbol. */
3308 info->dli_sname = obj->strtab + def->st_name;
3309 info->dli_saddr = symbol_addr;
3312 if (info->dli_saddr == addr)
3315 lock_release(rtld_bind_lock, &lockstate);
3320 dlinfo(void *handle, int request, void *p)
3322 const Obj_Entry *obj;
3323 RtldLockState lockstate;
3326 rlock_acquire(rtld_bind_lock, &lockstate);
3328 if (handle == NULL || handle == RTLD_SELF) {
3331 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3332 if ((obj = obj_from_addr(retaddr)) == NULL)
3333 _rtld_error("Cannot determine caller's shared object");
3335 obj = dlcheck(handle);
3338 lock_release(rtld_bind_lock, &lockstate);
3344 case RTLD_DI_LINKMAP:
3345 *((struct link_map const **)p) = &obj->linkmap;
3347 case RTLD_DI_ORIGIN:
3348 error = rtld_dirname(obj->path, p);
3351 case RTLD_DI_SERINFOSIZE:
3352 case RTLD_DI_SERINFO:
3353 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3357 _rtld_error("Invalid request %d passed to dlinfo()", request);
3361 lock_release(rtld_bind_lock, &lockstate);
3367 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3370 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3371 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
3372 STAILQ_FIRST(&obj->names)->name : obj->path;
3373 phdr_info->dlpi_phdr = obj->phdr;
3374 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3375 phdr_info->dlpi_tls_modid = obj->tlsindex;
3376 phdr_info->dlpi_tls_data = obj->tlsinit;
3377 phdr_info->dlpi_adds = obj_loads;
3378 phdr_info->dlpi_subs = obj_loads - obj_count;
3382 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3384 struct dl_phdr_info phdr_info;
3385 const Obj_Entry *obj;
3386 RtldLockState bind_lockstate, phdr_lockstate;
3389 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3390 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3394 for (obj = obj_list; obj != NULL; obj = obj->next) {
3395 rtld_fill_dl_phdr_info(obj, &phdr_info);
3396 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3401 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3402 error = callback(&phdr_info, sizeof(phdr_info), param);
3405 lock_release(rtld_bind_lock, &bind_lockstate);
3406 lock_release(rtld_phdr_lock, &phdr_lockstate);
3412 fill_search_info(const char *dir, size_t dirlen, void *param)
3414 struct fill_search_info_args *arg;
3418 if (arg->request == RTLD_DI_SERINFOSIZE) {
3419 arg->serinfo->dls_cnt ++;
3420 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3422 struct dl_serpath *s_entry;
3424 s_entry = arg->serpath;
3425 s_entry->dls_name = arg->strspace;
3426 s_entry->dls_flags = arg->flags;
3428 strncpy(arg->strspace, dir, dirlen);
3429 arg->strspace[dirlen] = '\0';
3431 arg->strspace += dirlen + 1;
3439 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3441 struct dl_serinfo _info;
3442 struct fill_search_info_args args;
3444 args.request = RTLD_DI_SERINFOSIZE;
3445 args.serinfo = &_info;
3447 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3450 path_enumerate(obj->rpath, fill_search_info, &args);
3451 path_enumerate(ld_library_path, fill_search_info, &args);
3452 path_enumerate(obj->runpath, fill_search_info, &args);
3453 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3454 if (!obj->z_nodeflib)
3455 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3458 if (request == RTLD_DI_SERINFOSIZE) {
3459 info->dls_size = _info.dls_size;
3460 info->dls_cnt = _info.dls_cnt;
3464 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3465 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3469 args.request = RTLD_DI_SERINFO;
3470 args.serinfo = info;
3471 args.serpath = &info->dls_serpath[0];
3472 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3474 args.flags = LA_SER_RUNPATH;
3475 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3478 args.flags = LA_SER_LIBPATH;
3479 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3482 args.flags = LA_SER_RUNPATH;
3483 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3486 args.flags = LA_SER_CONFIG;
3487 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3491 args.flags = LA_SER_DEFAULT;
3492 if (!obj->z_nodeflib &&
3493 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3499 rtld_dirname(const char *path, char *bname)
3503 /* Empty or NULL string gets treated as "." */
3504 if (path == NULL || *path == '\0') {
3510 /* Strip trailing slashes */
3511 endp = path + strlen(path) - 1;
3512 while (endp > path && *endp == '/')
3515 /* Find the start of the dir */
3516 while (endp > path && *endp != '/')
3519 /* Either the dir is "/" or there are no slashes */
3521 bname[0] = *endp == '/' ? '/' : '.';
3527 } while (endp > path && *endp == '/');
3530 if (endp - path + 2 > PATH_MAX)
3532 _rtld_error("Filename is too long: %s", path);
3536 strncpy(bname, path, endp - path + 1);
3537 bname[endp - path + 1] = '\0';
3542 rtld_dirname_abs(const char *path, char *base)
3544 char base_rel[PATH_MAX];
3546 if (rtld_dirname(path, base) == -1)
3550 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
3551 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
3552 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
3554 strcpy(base, base_rel);
3559 linkmap_add(Obj_Entry *obj)
3561 struct link_map *l = &obj->linkmap;
3562 struct link_map *prev;
3564 obj->linkmap.l_name = obj->path;
3565 obj->linkmap.l_addr = obj->mapbase;
3566 obj->linkmap.l_ld = obj->dynamic;
3568 /* GDB needs load offset on MIPS to use the symbols */
3569 obj->linkmap.l_offs = obj->relocbase;
3572 if (r_debug.r_map == NULL) {
3578 * Scan to the end of the list, but not past the entry for the
3579 * dynamic linker, which we want to keep at the very end.
3581 for (prev = r_debug.r_map;
3582 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3583 prev = prev->l_next)
3586 /* Link in the new entry. */
3588 l->l_next = prev->l_next;
3589 if (l->l_next != NULL)
3590 l->l_next->l_prev = l;
3595 linkmap_delete(Obj_Entry *obj)
3597 struct link_map *l = &obj->linkmap;
3599 if (l->l_prev == NULL) {
3600 if ((r_debug.r_map = l->l_next) != NULL)
3601 l->l_next->l_prev = NULL;
3605 if ((l->l_prev->l_next = l->l_next) != NULL)
3606 l->l_next->l_prev = l->l_prev;
3610 * Function for the debugger to set a breakpoint on to gain control.
3612 * The two parameters allow the debugger to easily find and determine
3613 * what the runtime loader is doing and to whom it is doing it.
3615 * When the loadhook trap is hit (r_debug_state, set at program
3616 * initialization), the arguments can be found on the stack:
3618 * +8 struct link_map *m
3619 * +4 struct r_debug *rd
3623 r_debug_state(struct r_debug* rd, struct link_map *m)
3626 * The following is a hack to force the compiler to emit calls to
3627 * this function, even when optimizing. If the function is empty,
3628 * the compiler is not obliged to emit any code for calls to it,
3629 * even when marked __noinline. However, gdb depends on those
3632 __compiler_membar();
3636 * A function called after init routines have completed. This can be used to
3637 * break before a program's entry routine is called, and can be used when
3638 * main is not available in the symbol table.
3641 _r_debug_postinit(struct link_map *m)
3644 /* See r_debug_state(). */
3645 __compiler_membar();
3649 * Get address of the pointer variable in the main program.
3650 * Prefer non-weak symbol over the weak one.
3652 static const void **
3653 get_program_var_addr(const char *name, RtldLockState *lockstate)
3658 symlook_init(&req, name);
3659 req.lockstate = lockstate;
3660 donelist_init(&donelist);
3661 if (symlook_global(&req, &donelist) != 0)
3663 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3664 return ((const void **)make_function_pointer(req.sym_out,
3666 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3667 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3669 return ((const void **)(req.defobj_out->relocbase +
3670 req.sym_out->st_value));
3674 * Set a pointer variable in the main program to the given value. This
3675 * is used to set key variables such as "environ" before any of the
3676 * init functions are called.
3679 set_program_var(const char *name, const void *value)
3683 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3684 dbg("\"%s\": *%p <-- %p", name, addr, value);
3690 * Search the global objects, including dependencies and main object,
3691 * for the given symbol.
3694 symlook_global(SymLook *req, DoneList *donelist)
3697 const Objlist_Entry *elm;
3700 symlook_init_from_req(&req1, req);
3702 /* Search all objects loaded at program start up. */
3703 if (req->defobj_out == NULL ||
3704 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3705 res = symlook_list(&req1, &list_main, donelist);
3706 if (res == 0 && (req->defobj_out == NULL ||
3707 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3708 req->sym_out = req1.sym_out;
3709 req->defobj_out = req1.defobj_out;
3710 assert(req->defobj_out != NULL);
3714 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3715 STAILQ_FOREACH(elm, &list_global, link) {
3716 if (req->defobj_out != NULL &&
3717 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3719 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3720 if (res == 0 && (req->defobj_out == NULL ||
3721 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3722 req->sym_out = req1.sym_out;
3723 req->defobj_out = req1.defobj_out;
3724 assert(req->defobj_out != NULL);
3728 return (req->sym_out != NULL ? 0 : ESRCH);
3732 * Given a symbol name in a referencing object, find the corresponding
3733 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3734 * no definition was found. Returns a pointer to the Obj_Entry of the
3735 * defining object via the reference parameter DEFOBJ_OUT.
3738 symlook_default(SymLook *req, const Obj_Entry *refobj)
3741 const Objlist_Entry *elm;
3745 donelist_init(&donelist);
3746 symlook_init_from_req(&req1, req);
3748 /* Look first in the referencing object if linked symbolically. */
3749 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3750 res = symlook_obj(&req1, refobj);
3752 req->sym_out = req1.sym_out;
3753 req->defobj_out = req1.defobj_out;
3754 assert(req->defobj_out != NULL);
3758 symlook_global(req, &donelist);
3760 /* Search all dlopened DAGs containing the referencing object. */
3761 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3762 if (req->sym_out != NULL &&
3763 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3765 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3766 if (res == 0 && (req->sym_out == NULL ||
3767 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3768 req->sym_out = req1.sym_out;
3769 req->defobj_out = req1.defobj_out;
3770 assert(req->defobj_out != NULL);
3775 * Search the dynamic linker itself, and possibly resolve the
3776 * symbol from there. This is how the application links to
3777 * dynamic linker services such as dlopen.
3779 if (req->sym_out == NULL ||
3780 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3781 res = symlook_obj(&req1, &obj_rtld);
3783 req->sym_out = req1.sym_out;
3784 req->defobj_out = req1.defobj_out;
3785 assert(req->defobj_out != NULL);
3789 return (req->sym_out != NULL ? 0 : ESRCH);
3793 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3796 const Obj_Entry *defobj;
3797 const Objlist_Entry *elm;
3803 STAILQ_FOREACH(elm, objlist, link) {
3804 if (donelist_check(dlp, elm->obj))
3806 symlook_init_from_req(&req1, req);
3807 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3808 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3810 defobj = req1.defobj_out;
3811 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3818 req->defobj_out = defobj;
3825 * Search the chain of DAGS cointed to by the given Needed_Entry
3826 * for a symbol of the given name. Each DAG is scanned completely
3827 * before advancing to the next one. Returns a pointer to the symbol,
3828 * or NULL if no definition was found.
3831 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3834 const Needed_Entry *n;
3835 const Obj_Entry *defobj;
3841 symlook_init_from_req(&req1, req);
3842 for (n = needed; n != NULL; n = n->next) {
3843 if (n->obj == NULL ||
3844 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3846 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3848 defobj = req1.defobj_out;
3849 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3855 req->defobj_out = defobj;
3862 * Search the symbol table of a single shared object for a symbol of
3863 * the given name and version, if requested. Returns a pointer to the
3864 * symbol, or NULL if no definition was found. If the object is
3865 * filter, return filtered symbol from filtee.
3867 * The symbol's hash value is passed in for efficiency reasons; that
3868 * eliminates many recomputations of the hash value.
3871 symlook_obj(SymLook *req, const Obj_Entry *obj)
3875 int flags, res, mres;
3878 * If there is at least one valid hash at this point, we prefer to
3879 * use the faster GNU version if available.
3881 if (obj->valid_hash_gnu)
3882 mres = symlook_obj1_gnu(req, obj);
3883 else if (obj->valid_hash_sysv)
3884 mres = symlook_obj1_sysv(req, obj);
3889 if (obj->needed_filtees != NULL) {
3890 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3891 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3892 donelist_init(&donelist);
3893 symlook_init_from_req(&req1, req);
3894 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3896 req->sym_out = req1.sym_out;
3897 req->defobj_out = req1.defobj_out;
3901 if (obj->needed_aux_filtees != NULL) {
3902 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3903 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3904 donelist_init(&donelist);
3905 symlook_init_from_req(&req1, req);
3906 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3908 req->sym_out = req1.sym_out;
3909 req->defobj_out = req1.defobj_out;
3917 /* Symbol match routine common to both hash functions */
3919 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3920 const unsigned long symnum)
3923 const Elf_Sym *symp;
3926 symp = obj->symtab + symnum;
3927 strp = obj->strtab + symp->st_name;
3929 switch (ELF_ST_TYPE(symp->st_info)) {
3935 if (symp->st_value == 0)
3939 if (symp->st_shndx != SHN_UNDEF)
3942 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3943 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3950 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3953 if (req->ventry == NULL) {
3954 if (obj->versyms != NULL) {
3955 verndx = VER_NDX(obj->versyms[symnum]);
3956 if (verndx > obj->vernum) {
3958 "%s: symbol %s references wrong version %d",
3959 obj->path, obj->strtab + symnum, verndx);
3963 * If we are not called from dlsym (i.e. this
3964 * is a normal relocation from unversioned
3965 * binary), accept the symbol immediately if
3966 * it happens to have first version after this
3967 * shared object became versioned. Otherwise,
3968 * if symbol is versioned and not hidden,
3969 * remember it. If it is the only symbol with
3970 * this name exported by the shared object, it
3971 * will be returned as a match by the calling
3972 * function. If symbol is global (verndx < 2)
3973 * accept it unconditionally.
3975 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3976 verndx == VER_NDX_GIVEN) {
3977 result->sym_out = symp;
3980 else if (verndx >= VER_NDX_GIVEN) {
3981 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
3983 if (result->vsymp == NULL)
3984 result->vsymp = symp;
3990 result->sym_out = symp;
3993 if (obj->versyms == NULL) {
3994 if (object_match_name(obj, req->ventry->name)) {
3995 _rtld_error("%s: object %s should provide version %s "
3996 "for symbol %s", obj_rtld.path, obj->path,
3997 req->ventry->name, obj->strtab + symnum);
4001 verndx = VER_NDX(obj->versyms[symnum]);
4002 if (verndx > obj->vernum) {
4003 _rtld_error("%s: symbol %s references wrong version %d",
4004 obj->path, obj->strtab + symnum, verndx);
4007 if (obj->vertab[verndx].hash != req->ventry->hash ||
4008 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4010 * Version does not match. Look if this is a
4011 * global symbol and if it is not hidden. If
4012 * global symbol (verndx < 2) is available,
4013 * use it. Do not return symbol if we are
4014 * called by dlvsym, because dlvsym looks for
4015 * a specific version and default one is not
4016 * what dlvsym wants.
4018 if ((req->flags & SYMLOOK_DLSYM) ||
4019 (verndx >= VER_NDX_GIVEN) ||
4020 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4024 result->sym_out = symp;
4029 * Search for symbol using SysV hash function.
4030 * obj->buckets is known not to be NULL at this point; the test for this was
4031 * performed with the obj->valid_hash_sysv assignment.
4034 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4036 unsigned long symnum;
4037 Sym_Match_Result matchres;
4039 matchres.sym_out = NULL;
4040 matchres.vsymp = NULL;
4041 matchres.vcount = 0;
4043 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4044 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4045 if (symnum >= obj->nchains)
4046 return (ESRCH); /* Bad object */
4048 if (matched_symbol(req, obj, &matchres, symnum)) {
4049 req->sym_out = matchres.sym_out;
4050 req->defobj_out = obj;
4054 if (matchres.vcount == 1) {
4055 req->sym_out = matchres.vsymp;
4056 req->defobj_out = obj;
4062 /* Search for symbol using GNU hash function */
4064 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4066 Elf_Addr bloom_word;
4067 const Elf32_Word *hashval;
4069 Sym_Match_Result matchres;
4070 unsigned int h1, h2;
4071 unsigned long symnum;
4073 matchres.sym_out = NULL;
4074 matchres.vsymp = NULL;
4075 matchres.vcount = 0;
4077 /* Pick right bitmask word from Bloom filter array */
4078 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4079 obj->maskwords_bm_gnu];
4081 /* Calculate modulus word size of gnu hash and its derivative */
4082 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4083 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4085 /* Filter out the "definitely not in set" queries */
4086 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4089 /* Locate hash chain and corresponding value element*/
4090 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4093 hashval = &obj->chain_zero_gnu[bucket];
4095 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4096 symnum = hashval - obj->chain_zero_gnu;
4097 if (matched_symbol(req, obj, &matchres, symnum)) {
4098 req->sym_out = matchres.sym_out;
4099 req->defobj_out = obj;
4103 } while ((*hashval++ & 1) == 0);
4104 if (matchres.vcount == 1) {
4105 req->sym_out = matchres.vsymp;
4106 req->defobj_out = obj;
4113 trace_loaded_objects(Obj_Entry *obj)
4115 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4118 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
4121 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
4122 fmt1 = "\t%o => %p (%x)\n";
4124 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
4125 fmt2 = "\t%o (%x)\n";
4127 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
4129 for (; obj; obj = obj->next) {
4130 Needed_Entry *needed;
4134 if (list_containers && obj->needed != NULL)
4135 rtld_printf("%s:\n", obj->path);
4136 for (needed = obj->needed; needed; needed = needed->next) {
4137 if (needed->obj != NULL) {
4138 if (needed->obj->traced && !list_containers)
4140 needed->obj->traced = true;
4141 path = needed->obj->path;
4145 name = (char *)obj->strtab + needed->name;
4146 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4148 fmt = is_lib ? fmt1 : fmt2;
4149 while ((c = *fmt++) != '\0') {
4175 rtld_putstr(main_local);
4178 rtld_putstr(obj_main->path);
4185 rtld_printf("%d", sodp->sod_major);
4188 rtld_printf("%d", sodp->sod_minor);
4195 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4208 * Unload a dlopened object and its dependencies from memory and from
4209 * our data structures. It is assumed that the DAG rooted in the
4210 * object has already been unreferenced, and that the object has a
4211 * reference count of 0.
4214 unload_object(Obj_Entry *root)
4219 assert(root->refcount == 0);
4222 * Pass over the DAG removing unreferenced objects from
4223 * appropriate lists.
4225 unlink_object(root);
4227 /* Unmap all objects that are no longer referenced. */
4228 linkp = &obj_list->next;
4229 while ((obj = *linkp) != NULL) {
4230 if (obj->refcount == 0) {
4231 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4233 dbg("unloading \"%s\"", obj->path);
4234 unload_filtees(root);
4235 munmap(obj->mapbase, obj->mapsize);
4236 linkmap_delete(obj);
4247 unlink_object(Obj_Entry *root)
4251 if (root->refcount == 0) {
4252 /* Remove the object from the RTLD_GLOBAL list. */
4253 objlist_remove(&list_global, root);
4255 /* Remove the object from all objects' DAG lists. */
4256 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4257 objlist_remove(&elm->obj->dldags, root);
4258 if (elm->obj != root)
4259 unlink_object(elm->obj);
4265 ref_dag(Obj_Entry *root)
4269 assert(root->dag_inited);
4270 STAILQ_FOREACH(elm, &root->dagmembers, link)
4271 elm->obj->refcount++;
4275 unref_dag(Obj_Entry *root)
4279 assert(root->dag_inited);
4280 STAILQ_FOREACH(elm, &root->dagmembers, link)
4281 elm->obj->refcount--;
4285 * Common code for MD __tls_get_addr().
4287 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4289 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4291 Elf_Addr *newdtv, *dtv;
4292 RtldLockState lockstate;
4296 /* Check dtv generation in case new modules have arrived */
4297 if (dtv[0] != tls_dtv_generation) {
4298 wlock_acquire(rtld_bind_lock, &lockstate);
4299 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4301 if (to_copy > tls_max_index)
4302 to_copy = tls_max_index;
4303 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4304 newdtv[0] = tls_dtv_generation;
4305 newdtv[1] = tls_max_index;
4307 lock_release(rtld_bind_lock, &lockstate);
4308 dtv = *dtvp = newdtv;
4311 /* Dynamically allocate module TLS if necessary */
4312 if (dtv[index + 1] == 0) {
4313 /* Signal safe, wlock will block out signals. */
4314 wlock_acquire(rtld_bind_lock, &lockstate);
4315 if (!dtv[index + 1])
4316 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4317 lock_release(rtld_bind_lock, &lockstate);
4319 return ((void *)(dtv[index + 1] + offset));
4323 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4328 /* Check dtv generation in case new modules have arrived */
4329 if (__predict_true(dtv[0] == tls_dtv_generation &&
4330 dtv[index + 1] != 0))
4331 return ((void *)(dtv[index + 1] + offset));
4332 return (tls_get_addr_slow(dtvp, index, offset));
4335 #if defined(__arm__) || defined(__mips__) || defined(__powerpc__)
4338 * Allocate Static TLS using the Variant I method.
4341 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4350 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4353 assert(tcbsize >= TLS_TCB_SIZE);
4354 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4355 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4357 if (oldtcb != NULL) {
4358 memcpy(tls, oldtcb, tls_static_space);
4361 /* Adjust the DTV. */
4363 for (i = 0; i < dtv[1]; i++) {
4364 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4365 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4366 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4370 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4372 dtv[0] = tls_dtv_generation;
4373 dtv[1] = tls_max_index;
4375 for (obj = objs; obj; obj = obj->next) {
4376 if (obj->tlsoffset > 0) {
4377 addr = (Elf_Addr)tls + obj->tlsoffset;
4378 if (obj->tlsinitsize > 0)
4379 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4380 if (obj->tlssize > obj->tlsinitsize)
4381 memset((void*) (addr + obj->tlsinitsize), 0,
4382 obj->tlssize - obj->tlsinitsize);
4383 dtv[obj->tlsindex + 1] = addr;
4392 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4395 Elf_Addr tlsstart, tlsend;
4398 assert(tcbsize >= TLS_TCB_SIZE);
4400 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4401 tlsend = tlsstart + tls_static_space;
4403 dtv = *(Elf_Addr **)tlsstart;
4405 for (i = 0; i < dtvsize; i++) {
4406 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4407 free((void*)dtv[i+2]);
4416 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4419 * Allocate Static TLS using the Variant II method.
4422 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4425 size_t size, ralign;
4427 Elf_Addr *dtv, *olddtv;
4428 Elf_Addr segbase, oldsegbase, addr;
4432 if (tls_static_max_align > ralign)
4433 ralign = tls_static_max_align;
4434 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4436 assert(tcbsize >= 2*sizeof(Elf_Addr));
4437 tls = malloc_aligned(size, ralign);
4438 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4440 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4441 ((Elf_Addr*)segbase)[0] = segbase;
4442 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4444 dtv[0] = tls_dtv_generation;
4445 dtv[1] = tls_max_index;
4449 * Copy the static TLS block over whole.
4451 oldsegbase = (Elf_Addr) oldtls;
4452 memcpy((void *)(segbase - tls_static_space),
4453 (const void *)(oldsegbase - tls_static_space),
4457 * If any dynamic TLS blocks have been created tls_get_addr(),
4460 olddtv = ((Elf_Addr**)oldsegbase)[1];
4461 for (i = 0; i < olddtv[1]; i++) {
4462 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4463 dtv[i+2] = olddtv[i+2];
4469 * We assume that this block was the one we created with
4470 * allocate_initial_tls().
4472 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4474 for (obj = objs; obj; obj = obj->next) {
4475 if (obj->tlsoffset) {
4476 addr = segbase - obj->tlsoffset;
4477 memset((void*) (addr + obj->tlsinitsize),
4478 0, obj->tlssize - obj->tlsinitsize);
4480 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4481 dtv[obj->tlsindex + 1] = addr;
4486 return (void*) segbase;
4490 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4493 size_t size, ralign;
4495 Elf_Addr tlsstart, tlsend;
4498 * Figure out the size of the initial TLS block so that we can
4499 * find stuff which ___tls_get_addr() allocated dynamically.
4502 if (tls_static_max_align > ralign)
4503 ralign = tls_static_max_align;
4504 size = round(tls_static_space, ralign);
4506 dtv = ((Elf_Addr**)tls)[1];
4508 tlsend = (Elf_Addr) tls;
4509 tlsstart = tlsend - size;
4510 for (i = 0; i < dtvsize; i++) {
4511 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4512 free_aligned((void *)dtv[i + 2]);
4516 free_aligned((void *)tlsstart);
4523 * Allocate TLS block for module with given index.
4526 allocate_module_tls(int index)
4531 for (obj = obj_list; obj; obj = obj->next) {
4532 if (obj->tlsindex == index)
4536 _rtld_error("Can't find module with TLS index %d", index);
4540 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4541 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4542 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4548 allocate_tls_offset(Obj_Entry *obj)
4555 if (obj->tlssize == 0) {
4556 obj->tls_done = true;
4560 if (obj->tlsindex == 1)
4561 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4563 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4564 obj->tlssize, obj->tlsalign);
4567 * If we have already fixed the size of the static TLS block, we
4568 * must stay within that size. When allocating the static TLS, we
4569 * leave a small amount of space spare to be used for dynamically
4570 * loading modules which use static TLS.
4572 if (tls_static_space != 0) {
4573 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4575 } else if (obj->tlsalign > tls_static_max_align) {
4576 tls_static_max_align = obj->tlsalign;
4579 tls_last_offset = obj->tlsoffset = off;
4580 tls_last_size = obj->tlssize;
4581 obj->tls_done = true;
4587 free_tls_offset(Obj_Entry *obj)
4591 * If we were the last thing to allocate out of the static TLS
4592 * block, we give our space back to the 'allocator'. This is a
4593 * simplistic workaround to allow libGL.so.1 to be loaded and
4594 * unloaded multiple times.
4596 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4597 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4598 tls_last_offset -= obj->tlssize;
4604 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4607 RtldLockState lockstate;
4609 wlock_acquire(rtld_bind_lock, &lockstate);
4610 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4611 lock_release(rtld_bind_lock, &lockstate);
4616 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4618 RtldLockState lockstate;
4620 wlock_acquire(rtld_bind_lock, &lockstate);
4621 free_tls(tcb, tcbsize, tcbalign);
4622 lock_release(rtld_bind_lock, &lockstate);
4626 object_add_name(Obj_Entry *obj, const char *name)
4632 entry = malloc(sizeof(Name_Entry) + len);
4634 if (entry != NULL) {
4635 strcpy(entry->name, name);
4636 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4641 object_match_name(const Obj_Entry *obj, const char *name)
4645 STAILQ_FOREACH(entry, &obj->names, link) {
4646 if (strcmp(name, entry->name) == 0)
4653 locate_dependency(const Obj_Entry *obj, const char *name)
4655 const Objlist_Entry *entry;
4656 const Needed_Entry *needed;
4658 STAILQ_FOREACH(entry, &list_main, link) {
4659 if (object_match_name(entry->obj, name))
4663 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4664 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4665 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4667 * If there is DT_NEEDED for the name we are looking for,
4668 * we are all set. Note that object might not be found if
4669 * dependency was not loaded yet, so the function can
4670 * return NULL here. This is expected and handled
4671 * properly by the caller.
4673 return (needed->obj);
4676 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4682 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4683 const Elf_Vernaux *vna)
4685 const Elf_Verdef *vd;
4686 const char *vername;
4688 vername = refobj->strtab + vna->vna_name;
4689 vd = depobj->verdef;
4691 _rtld_error("%s: version %s required by %s not defined",
4692 depobj->path, vername, refobj->path);
4696 if (vd->vd_version != VER_DEF_CURRENT) {
4697 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4698 depobj->path, vd->vd_version);
4701 if (vna->vna_hash == vd->vd_hash) {
4702 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4703 ((char *)vd + vd->vd_aux);
4704 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4707 if (vd->vd_next == 0)
4709 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4711 if (vna->vna_flags & VER_FLG_WEAK)
4713 _rtld_error("%s: version %s required by %s not found",
4714 depobj->path, vername, refobj->path);
4719 rtld_verify_object_versions(Obj_Entry *obj)
4721 const Elf_Verneed *vn;
4722 const Elf_Verdef *vd;
4723 const Elf_Verdaux *vda;
4724 const Elf_Vernaux *vna;
4725 const Obj_Entry *depobj;
4726 int maxvernum, vernum;
4728 if (obj->ver_checked)
4730 obj->ver_checked = true;
4734 * Walk over defined and required version records and figure out
4735 * max index used by any of them. Do very basic sanity checking
4739 while (vn != NULL) {
4740 if (vn->vn_version != VER_NEED_CURRENT) {
4741 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4742 obj->path, vn->vn_version);
4745 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4747 vernum = VER_NEED_IDX(vna->vna_other);
4748 if (vernum > maxvernum)
4750 if (vna->vna_next == 0)
4752 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4754 if (vn->vn_next == 0)
4756 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4760 while (vd != NULL) {
4761 if (vd->vd_version != VER_DEF_CURRENT) {
4762 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4763 obj->path, vd->vd_version);
4766 vernum = VER_DEF_IDX(vd->vd_ndx);
4767 if (vernum > maxvernum)
4769 if (vd->vd_next == 0)
4771 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4778 * Store version information in array indexable by version index.
4779 * Verify that object version requirements are satisfied along the
4782 obj->vernum = maxvernum + 1;
4783 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4786 while (vd != NULL) {
4787 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4788 vernum = VER_DEF_IDX(vd->vd_ndx);
4789 assert(vernum <= maxvernum);
4790 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4791 obj->vertab[vernum].hash = vd->vd_hash;
4792 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4793 obj->vertab[vernum].file = NULL;
4794 obj->vertab[vernum].flags = 0;
4796 if (vd->vd_next == 0)
4798 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4802 while (vn != NULL) {
4803 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4806 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4808 if (check_object_provided_version(obj, depobj, vna))
4810 vernum = VER_NEED_IDX(vna->vna_other);
4811 assert(vernum <= maxvernum);
4812 obj->vertab[vernum].hash = vna->vna_hash;
4813 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4814 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4815 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4816 VER_INFO_HIDDEN : 0;
4817 if (vna->vna_next == 0)
4819 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4821 if (vn->vn_next == 0)
4823 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4829 rtld_verify_versions(const Objlist *objlist)
4831 Objlist_Entry *entry;
4835 STAILQ_FOREACH(entry, objlist, link) {
4837 * Skip dummy objects or objects that have their version requirements
4840 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4842 if (rtld_verify_object_versions(entry->obj) == -1) {
4844 if (ld_tracing == NULL)
4848 if (rc == 0 || ld_tracing != NULL)
4849 rc = rtld_verify_object_versions(&obj_rtld);
4854 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4859 vernum = VER_NDX(obj->versyms[symnum]);
4860 if (vernum >= obj->vernum) {
4861 _rtld_error("%s: symbol %s has wrong verneed value %d",
4862 obj->path, obj->strtab + symnum, vernum);
4863 } else if (obj->vertab[vernum].hash != 0) {
4864 return &obj->vertab[vernum];
4871 _rtld_get_stack_prot(void)
4874 return (stack_prot);
4878 map_stacks_exec(RtldLockState *lockstate)
4880 void (*thr_map_stacks_exec)(void);
4882 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4884 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4885 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4886 if (thr_map_stacks_exec != NULL) {
4887 stack_prot |= PROT_EXEC;
4888 thr_map_stacks_exec();
4893 symlook_init(SymLook *dst, const char *name)
4896 bzero(dst, sizeof(*dst));
4898 dst->hash = elf_hash(name);
4899 dst->hash_gnu = gnu_hash(name);
4903 symlook_init_from_req(SymLook *dst, const SymLook *src)
4906 dst->name = src->name;
4907 dst->hash = src->hash;
4908 dst->hash_gnu = src->hash_gnu;
4909 dst->ventry = src->ventry;
4910 dst->flags = src->flags;
4911 dst->defobj_out = NULL;
4912 dst->sym_out = NULL;
4913 dst->lockstate = src->lockstate;
4918 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
4921 parse_libdir(const char *str)
4923 static const int RADIX = 10; /* XXXJA: possibly support hex? */
4930 for (c = *str; c != '\0'; c = *++str) {
4931 if (c < '0' || c > '9')
4938 /* Make sure we actually parsed something. */
4940 _rtld_error("failed to parse directory FD from '%s'", str);
4947 * Overrides for libc_pic-provided functions.
4951 __getosreldate(void)
4961 oid[1] = KERN_OSRELDATE;
4963 len = sizeof(osrel);
4964 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4965 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4977 void (*__cleanup)(void);
4978 int __isthreaded = 0;
4979 int _thread_autoinit_dummy_decl = 1;
4982 * No unresolved symbols for rtld.
4985 __pthread_cxa_finalize(struct dl_phdr_info *a)
4990 __stack_chk_fail(void)
4993 _rtld_error("stack overflow detected; terminated");
4996 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
5002 _rtld_error("buffer overflow detected; terminated");
5007 rtld_strerror(int errnum)
5010 if (errnum < 0 || errnum >= sys_nerr)
5011 return ("Unknown error");
5012 return (sys_errlist[errnum]);