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;
508 * Get the actual dynamic linker pathname from the executable if
509 * possible. (It should always be possible.) That ensures that
510 * gdb will find the right dynamic linker even if a non-standard
513 if (obj_main->interp != NULL &&
514 strcmp(obj_main->interp, obj_rtld.path) != 0) {
516 obj_rtld.path = xstrdup(obj_main->interp);
517 __progname = obj_rtld.path;
521 digest_dynamic(obj_main, 0);
522 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
523 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
524 obj_main->dynsymcount);
526 linkmap_add(obj_main);
527 linkmap_add(&obj_rtld);
529 /* Link the main program into the list of objects. */
530 *obj_tail = obj_main;
531 obj_tail = &obj_main->next;
535 /* Initialize a fake symbol for resolving undefined weak references. */
536 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
537 sym_zero.st_shndx = SHN_UNDEF;
538 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
541 libmap_disable = (bool)lm_init(libmap_override);
543 dbg("loading LD_PRELOAD libraries");
544 if (load_preload_objects() == -1)
546 preload_tail = obj_tail;
548 dbg("loading needed objects");
549 if (load_needed_objects(obj_main, 0) == -1)
552 /* Make a list of all objects loaded at startup. */
553 last_interposer = obj_main;
554 for (obj = obj_list; obj != NULL; obj = obj->next) {
555 if (obj->z_interpose && obj != obj_main) {
556 objlist_put_after(&list_main, last_interposer, obj);
557 last_interposer = obj;
559 objlist_push_tail(&list_main, obj);
564 dbg("checking for required versions");
565 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
568 if (ld_tracing) { /* We're done */
569 trace_loaded_objects(obj_main);
573 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
574 dump_relocations(obj_main);
579 * Processing tls relocations requires having the tls offsets
580 * initialized. Prepare offsets before starting initial
581 * relocation processing.
583 dbg("initializing initial thread local storage offsets");
584 STAILQ_FOREACH(entry, &list_main, link) {
586 * Allocate all the initial objects out of the static TLS
587 * block even if they didn't ask for it.
589 allocate_tls_offset(entry->obj);
592 if (relocate_objects(obj_main,
593 ld_bind_now != NULL && *ld_bind_now != '\0',
594 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
597 dbg("doing copy relocations");
598 if (do_copy_relocations(obj_main) == -1)
601 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
602 dump_relocations(obj_main);
607 * Setup TLS for main thread. This must be done after the
608 * relocations are processed, since tls initialization section
609 * might be the subject for relocations.
611 dbg("initializing initial thread local storage");
612 allocate_initial_tls(obj_list);
614 dbg("initializing key program variables");
615 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
616 set_program_var("environ", env);
617 set_program_var("__elf_aux_vector", aux);
619 /* Make a list of init functions to call. */
620 objlist_init(&initlist);
621 initlist_add_objects(obj_list, preload_tail, &initlist);
623 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
625 map_stacks_exec(NULL);
627 dbg("resolving ifuncs");
628 if (resolve_objects_ifunc(obj_main,
629 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
633 if (!obj_main->crt_no_init) {
635 * Make sure we don't call the main program's init and fini
636 * functions for binaries linked with old crt1 which calls
639 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
640 obj_main->preinit_array = obj_main->init_array =
641 obj_main->fini_array = (Elf_Addr)NULL;
644 wlock_acquire(rtld_bind_lock, &lockstate);
645 if (obj_main->crt_no_init)
647 objlist_call_init(&initlist, &lockstate);
648 _r_debug_postinit(&obj_main->linkmap);
649 objlist_clear(&initlist);
650 dbg("loading filtees");
651 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
652 if (ld_loadfltr || obj->z_loadfltr)
653 load_filtees(obj, 0, &lockstate);
655 lock_release(rtld_bind_lock, &lockstate);
657 dbg("transferring control to program entry point = %p", obj_main->entry);
659 /* Return the exit procedure and the program entry point. */
660 *exit_proc = rtld_exit;
662 return (func_ptr_type) obj_main->entry;
666 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
671 ptr = (void *)make_function_pointer(def, obj);
672 target = ((Elf_Addr (*)(void))ptr)();
673 return ((void *)target);
677 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
681 const Obj_Entry *defobj;
684 RtldLockState lockstate;
686 rlock_acquire(rtld_bind_lock, &lockstate);
687 if (sigsetjmp(lockstate.env, 0) != 0)
688 lock_upgrade(rtld_bind_lock, &lockstate);
690 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
692 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
694 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
695 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
699 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
700 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
702 target = (Elf_Addr)(defobj->relocbase + def->st_value);
704 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
705 defobj->strtab + def->st_name, basename(obj->path),
706 (void *)target, basename(defobj->path));
709 * Write the new contents for the jmpslot. Note that depending on
710 * architecture, the value which we need to return back to the
711 * lazy binding trampoline may or may not be the target
712 * address. The value returned from reloc_jmpslot() is the value
713 * that the trampoline needs.
715 target = reloc_jmpslot(where, target, defobj, obj, rel);
716 lock_release(rtld_bind_lock, &lockstate);
721 * Error reporting function. Use it like printf. If formats the message
722 * into a buffer, and sets things up so that the next call to dlerror()
723 * will return the message.
726 _rtld_error(const char *fmt, ...)
728 static char buf[512];
732 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
738 * Return a dynamically-allocated copy of the current error message, if any.
743 return error_message == NULL ? NULL : xstrdup(error_message);
747 * Restore the current error message from a copy which was previously saved
748 * by errmsg_save(). The copy is freed.
751 errmsg_restore(char *saved_msg)
753 if (saved_msg == NULL)
754 error_message = NULL;
756 _rtld_error("%s", saved_msg);
762 basename(const char *name)
764 const char *p = strrchr(name, '/');
765 return p != NULL ? p + 1 : name;
768 static struct utsname uts;
771 origin_subst_one(char *real, const char *kw, const char *subst,
774 char *p, *p1, *res, *resp;
775 int subst_len, kw_len, subst_count, old_len, new_len;
780 * First, count the number of the keyword occurences, to
781 * preallocate the final string.
783 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
790 * If the keyword is not found, just return.
792 if (subst_count == 0)
793 return (may_free ? real : xstrdup(real));
796 * There is indeed something to substitute. Calculate the
797 * length of the resulting string, and allocate it.
799 subst_len = strlen(subst);
800 old_len = strlen(real);
801 new_len = old_len + (subst_len - kw_len) * subst_count;
802 res = xmalloc(new_len + 1);
805 * Now, execute the substitution loop.
807 for (p = real, resp = res, *resp = '\0';;) {
810 /* Copy the prefix before keyword. */
811 memcpy(resp, p, p1 - p);
813 /* Keyword replacement. */
814 memcpy(resp, subst, subst_len);
822 /* Copy to the end of string and finish. */
830 origin_subst(char *real, const char *origin_path)
832 char *res1, *res2, *res3, *res4;
834 if (uts.sysname[0] == '\0') {
835 if (uname(&uts) != 0) {
836 _rtld_error("utsname failed: %d", errno);
840 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false);
841 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true);
842 res3 = origin_subst_one(res2, "$OSREL", uts.release, true);
843 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true);
850 const char *msg = dlerror();
854 rtld_fdputstr(STDERR_FILENO, msg);
855 rtld_fdputchar(STDERR_FILENO, '\n');
860 * Process a shared object's DYNAMIC section, and save the important
861 * information in its Obj_Entry structure.
864 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
865 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
868 Needed_Entry **needed_tail = &obj->needed;
869 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
870 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
871 const Elf_Hashelt *hashtab;
872 const Elf32_Word *hashval;
873 Elf32_Word bkt, nmaskwords;
876 int plttype = DT_REL;
882 obj->bind_now = false;
883 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
884 switch (dynp->d_tag) {
887 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
891 obj->relsize = dynp->d_un.d_val;
895 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
899 obj->pltrel = (const Elf_Rel *)
900 (obj->relocbase + dynp->d_un.d_ptr);
904 obj->pltrelsize = dynp->d_un.d_val;
908 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
912 obj->relasize = dynp->d_un.d_val;
916 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
920 plttype = dynp->d_un.d_val;
921 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
925 obj->symtab = (const Elf_Sym *)
926 (obj->relocbase + dynp->d_un.d_ptr);
930 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
934 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
938 obj->strsize = dynp->d_un.d_val;
942 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
947 obj->verneednum = dynp->d_un.d_val;
951 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
956 obj->verdefnum = dynp->d_un.d_val;
960 obj->versyms = (const Elf_Versym *)(obj->relocbase +
966 hashtab = (const Elf_Hashelt *)(obj->relocbase +
968 obj->nbuckets = hashtab[0];
969 obj->nchains = hashtab[1];
970 obj->buckets = hashtab + 2;
971 obj->chains = obj->buckets + obj->nbuckets;
972 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
973 obj->buckets != NULL;
979 hashtab = (const Elf_Hashelt *)(obj->relocbase +
981 obj->nbuckets_gnu = hashtab[0];
982 obj->symndx_gnu = hashtab[1];
983 nmaskwords = hashtab[2];
984 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
985 /* Number of bitmask words is required to be power of 2 */
986 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0);
987 obj->maskwords_bm_gnu = nmaskwords - 1;
988 obj->shift2_gnu = hashtab[3];
989 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
990 obj->buckets_gnu = hashtab + 4 + bloom_size32;
991 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
993 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 &&
994 obj->buckets_gnu != NULL;
1000 Needed_Entry *nep = NEW(Needed_Entry);
1001 nep->name = dynp->d_un.d_val;
1006 needed_tail = &nep->next;
1012 Needed_Entry *nep = NEW(Needed_Entry);
1013 nep->name = dynp->d_un.d_val;
1017 *needed_filtees_tail = nep;
1018 needed_filtees_tail = &nep->next;
1024 Needed_Entry *nep = NEW(Needed_Entry);
1025 nep->name = dynp->d_un.d_val;
1029 *needed_aux_filtees_tail = nep;
1030 needed_aux_filtees_tail = &nep->next;
1035 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1039 obj->textrel = true;
1043 obj->symbolic = true;
1048 * We have to wait until later to process this, because we
1049 * might not have gotten the address of the string table yet.
1059 *dyn_runpath = dynp;
1063 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1066 case DT_PREINIT_ARRAY:
1067 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1070 case DT_PREINIT_ARRAYSZ:
1071 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1075 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1078 case DT_INIT_ARRAYSZ:
1079 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1083 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1087 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1090 case DT_FINI_ARRAYSZ:
1091 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1095 * Don't process DT_DEBUG on MIPS as the dynamic section
1096 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1101 /* XXX - not implemented yet */
1103 dbg("Filling in DT_DEBUG entry");
1104 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1109 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1110 obj->z_origin = true;
1111 if (dynp->d_un.d_val & DF_SYMBOLIC)
1112 obj->symbolic = true;
1113 if (dynp->d_un.d_val & DF_TEXTREL)
1114 obj->textrel = true;
1115 if (dynp->d_un.d_val & DF_BIND_NOW)
1116 obj->bind_now = true;
1117 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1121 case DT_MIPS_LOCAL_GOTNO:
1122 obj->local_gotno = dynp->d_un.d_val;
1125 case DT_MIPS_SYMTABNO:
1126 obj->symtabno = dynp->d_un.d_val;
1129 case DT_MIPS_GOTSYM:
1130 obj->gotsym = dynp->d_un.d_val;
1133 case DT_MIPS_RLD_MAP:
1134 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1139 if (dynp->d_un.d_val & DF_1_NOOPEN)
1140 obj->z_noopen = true;
1141 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1142 obj->z_origin = true;
1143 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1145 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1146 obj->bind_now = true;
1147 if (dynp->d_un.d_val & DF_1_NODELETE)
1148 obj->z_nodelete = true;
1149 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1150 obj->z_loadfltr = true;
1151 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1152 obj->z_interpose = true;
1153 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1154 obj->z_nodeflib = true;
1159 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1166 obj->traced = false;
1168 if (plttype == DT_RELA) {
1169 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1171 obj->pltrelasize = obj->pltrelsize;
1172 obj->pltrelsize = 0;
1175 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1176 if (obj->valid_hash_sysv)
1177 obj->dynsymcount = obj->nchains;
1178 else if (obj->valid_hash_gnu) {
1179 obj->dynsymcount = 0;
1180 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1181 if (obj->buckets_gnu[bkt] == 0)
1183 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1186 while ((*hashval++ & 1u) == 0);
1188 obj->dynsymcount += obj->symndx_gnu;
1193 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1194 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1197 if (obj->z_origin && obj->origin_path == NULL) {
1198 obj->origin_path = xmalloc(PATH_MAX);
1199 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1203 if (dyn_runpath != NULL) {
1204 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1206 obj->runpath = origin_subst(obj->runpath, obj->origin_path);
1208 else if (dyn_rpath != NULL) {
1209 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1211 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1214 if (dyn_soname != NULL)
1215 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1219 digest_dynamic(Obj_Entry *obj, int early)
1221 const Elf_Dyn *dyn_rpath;
1222 const Elf_Dyn *dyn_soname;
1223 const Elf_Dyn *dyn_runpath;
1225 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1226 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1230 * Process a shared object's program header. This is used only for the
1231 * main program, when the kernel has already loaded the main program
1232 * into memory before calling the dynamic linker. It creates and
1233 * returns an Obj_Entry structure.
1236 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1239 const Elf_Phdr *phlimit = phdr + phnum;
1241 Elf_Addr note_start, note_end;
1245 for (ph = phdr; ph < phlimit; ph++) {
1246 if (ph->p_type != PT_PHDR)
1250 obj->phsize = ph->p_memsz;
1251 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1255 obj->stack_flags = PF_X | PF_R | PF_W;
1257 for (ph = phdr; ph < phlimit; ph++) {
1258 switch (ph->p_type) {
1261 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1265 if (nsegs == 0) { /* First load segment */
1266 obj->vaddrbase = trunc_page(ph->p_vaddr);
1267 obj->mapbase = obj->vaddrbase + obj->relocbase;
1268 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1270 } else { /* Last load segment */
1271 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1278 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1283 obj->tlssize = ph->p_memsz;
1284 obj->tlsalign = ph->p_align;
1285 obj->tlsinitsize = ph->p_filesz;
1286 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1290 obj->stack_flags = ph->p_flags;
1294 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1295 obj->relro_size = round_page(ph->p_memsz);
1299 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1300 note_end = note_start + ph->p_filesz;
1301 digest_notes(obj, note_start, note_end);
1306 _rtld_error("%s: too few PT_LOAD segments", path);
1315 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1317 const Elf_Note *note;
1318 const char *note_name;
1321 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1322 note = (const Elf_Note *)((const char *)(note + 1) +
1323 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1324 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1325 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1326 note->n_descsz != sizeof(int32_t))
1328 if (note->n_type != ABI_NOTETYPE &&
1329 note->n_type != CRT_NOINIT_NOTETYPE)
1331 note_name = (const char *)(note + 1);
1332 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1333 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1335 switch (note->n_type) {
1337 /* FreeBSD osrel note */
1338 p = (uintptr_t)(note + 1);
1339 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1340 obj->osrel = *(const int32_t *)(p);
1341 dbg("note osrel %d", obj->osrel);
1343 case CRT_NOINIT_NOTETYPE:
1344 /* FreeBSD 'crt does not call init' note */
1345 obj->crt_no_init = true;
1346 dbg("note crt_no_init");
1353 dlcheck(void *handle)
1357 for (obj = obj_list; obj != NULL; obj = obj->next)
1358 if (obj == (Obj_Entry *) handle)
1361 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1362 _rtld_error("Invalid shared object handle %p", handle);
1369 * If the given object is already in the donelist, return true. Otherwise
1370 * add the object to the list and return false.
1373 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1377 for (i = 0; i < dlp->num_used; i++)
1378 if (dlp->objs[i] == obj)
1381 * Our donelist allocation should always be sufficient. But if
1382 * our threads locking isn't working properly, more shared objects
1383 * could have been loaded since we allocated the list. That should
1384 * never happen, but we'll handle it properly just in case it does.
1386 if (dlp->num_used < dlp->num_alloc)
1387 dlp->objs[dlp->num_used++] = obj;
1392 * Hash function for symbol table lookup. Don't even think about changing
1393 * this. It is specified by the System V ABI.
1396 elf_hash(const char *name)
1398 const unsigned char *p = (const unsigned char *) name;
1399 unsigned long h = 0;
1402 while (*p != '\0') {
1403 h = (h << 4) + *p++;
1404 if ((g = h & 0xf0000000) != 0)
1412 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1413 * unsigned in case it's implemented with a wider type.
1416 gnu_hash(const char *s)
1422 for (c = *s; c != '\0'; c = *++s)
1424 return (h & 0xffffffff);
1429 * Find the library with the given name, and return its full pathname.
1430 * The returned string is dynamically allocated. Generates an error
1431 * message and returns NULL if the library cannot be found.
1433 * If the second argument is non-NULL, then it refers to an already-
1434 * loaded shared object, whose library search path will be searched.
1436 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1437 * descriptor (which is close-on-exec) will be passed out via the third
1440 * The search order is:
1441 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1442 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1444 * DT_RUNPATH in the referencing file
1445 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1447 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1449 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1452 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1456 bool nodeflib, objgiven;
1458 objgiven = refobj != NULL;
1459 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1460 if (xname[0] != '/' && !trust) {
1461 _rtld_error("Absolute pathname required for shared object \"%s\"",
1465 if (objgiven && refobj->z_origin) {
1466 return (origin_subst(__DECONST(char *, xname),
1467 refobj->origin_path));
1469 return (xstrdup(xname));
1473 if (libmap_disable || !objgiven ||
1474 (name = lm_find(refobj->path, xname)) == NULL)
1475 name = (char *)xname;
1477 dbg(" Searching for \"%s\"", name);
1480 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1481 * back to pre-conforming behaviour if user requested so with
1482 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1485 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1486 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1488 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1489 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL ||
1490 (pathname = search_library_path(name, gethints(false))) != NULL ||
1491 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1494 nodeflib = objgiven ? refobj->z_nodeflib : false;
1496 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1497 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1498 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1499 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1501 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1502 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL ||
1503 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1504 (objgiven && !nodeflib &&
1505 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1509 if (objgiven && refobj->path != NULL) {
1510 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1511 name, basename(refobj->path));
1513 _rtld_error("Shared object \"%s\" not found", name);
1519 * Given a symbol number in a referencing object, find the corresponding
1520 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1521 * no definition was found. Returns a pointer to the Obj_Entry of the
1522 * defining object via the reference parameter DEFOBJ_OUT.
1525 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1526 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1527 RtldLockState *lockstate)
1531 const Obj_Entry *defobj;
1537 * If we have already found this symbol, get the information from
1540 if (symnum >= refobj->dynsymcount)
1541 return NULL; /* Bad object */
1542 if (cache != NULL && cache[symnum].sym != NULL) {
1543 *defobj_out = cache[symnum].obj;
1544 return cache[symnum].sym;
1547 ref = refobj->symtab + symnum;
1548 name = refobj->strtab + ref->st_name;
1553 * We don't have to do a full scale lookup if the symbol is local.
1554 * We know it will bind to the instance in this load module; to
1555 * which we already have a pointer (ie ref). By not doing a lookup,
1556 * we not only improve performance, but it also avoids unresolvable
1557 * symbols when local symbols are not in the hash table. This has
1558 * been seen with the ia64 toolchain.
1560 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1561 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1562 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1565 symlook_init(&req, name);
1567 req.ventry = fetch_ventry(refobj, symnum);
1568 req.lockstate = lockstate;
1569 res = symlook_default(&req, refobj);
1572 defobj = req.defobj_out;
1580 * If we found no definition and the reference is weak, treat the
1581 * symbol as having the value zero.
1583 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1589 *defobj_out = defobj;
1590 /* Record the information in the cache to avoid subsequent lookups. */
1591 if (cache != NULL) {
1592 cache[symnum].sym = def;
1593 cache[symnum].obj = defobj;
1596 if (refobj != &obj_rtld)
1597 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1603 * Return the search path from the ldconfig hints file, reading it if
1604 * necessary. If nostdlib is true, then the default search paths are
1605 * not added to result.
1607 * Returns NULL if there are problems with the hints file,
1608 * or if the search path there is empty.
1611 gethints(bool nostdlib)
1613 static char *hints, *filtered_path;
1614 struct elfhints_hdr hdr;
1615 struct fill_search_info_args sargs, hargs;
1616 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1617 struct dl_serpath *SLPpath, *hintpath;
1619 unsigned int SLPndx, hintndx, fndx, fcount;
1624 /* First call, read the hints file */
1625 if (hints == NULL) {
1626 /* Keep from trying again in case the hints file is bad. */
1629 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1631 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1632 hdr.magic != ELFHINTS_MAGIC ||
1637 p = xmalloc(hdr.dirlistlen + 1);
1638 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1639 read(fd, p, hdr.dirlistlen + 1) !=
1640 (ssize_t)hdr.dirlistlen + 1) {
1650 * If caller agreed to receive list which includes the default
1651 * paths, we are done. Otherwise, if we still did not
1652 * calculated filtered result, do it now.
1655 return (hints[0] != '\0' ? hints : NULL);
1656 if (filtered_path != NULL)
1660 * Obtain the list of all configured search paths, and the
1661 * list of the default paths.
1663 * First estimate the size of the results.
1665 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1667 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1670 sargs.request = RTLD_DI_SERINFOSIZE;
1671 sargs.serinfo = &smeta;
1672 hargs.request = RTLD_DI_SERINFOSIZE;
1673 hargs.serinfo = &hmeta;
1675 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1676 path_enumerate(p, fill_search_info, &hargs);
1678 SLPinfo = xmalloc(smeta.dls_size);
1679 hintinfo = xmalloc(hmeta.dls_size);
1682 * Next fetch both sets of paths.
1684 sargs.request = RTLD_DI_SERINFO;
1685 sargs.serinfo = SLPinfo;
1686 sargs.serpath = &SLPinfo->dls_serpath[0];
1687 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1689 hargs.request = RTLD_DI_SERINFO;
1690 hargs.serinfo = hintinfo;
1691 hargs.serpath = &hintinfo->dls_serpath[0];
1692 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1694 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1695 path_enumerate(p, fill_search_info, &hargs);
1698 * Now calculate the difference between two sets, by excluding
1699 * standard paths from the full set.
1703 filtered_path = xmalloc(hdr.dirlistlen + 1);
1704 hintpath = &hintinfo->dls_serpath[0];
1705 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1707 SLPpath = &SLPinfo->dls_serpath[0];
1709 * Check each standard path against current.
1711 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1712 /* matched, skip the path */
1713 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1721 * Not matched against any standard path, add the path
1722 * to result. Separate consequtive paths with ':'.
1725 filtered_path[fndx] = ':';
1729 flen = strlen(hintpath->dls_name);
1730 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1733 filtered_path[fndx] = '\0';
1739 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1743 init_dag(Obj_Entry *root)
1745 const Needed_Entry *needed;
1746 const Objlist_Entry *elm;
1749 if (root->dag_inited)
1751 donelist_init(&donelist);
1753 /* Root object belongs to own DAG. */
1754 objlist_push_tail(&root->dldags, root);
1755 objlist_push_tail(&root->dagmembers, root);
1756 donelist_check(&donelist, root);
1759 * Add dependencies of root object to DAG in breadth order
1760 * by exploiting the fact that each new object get added
1761 * to the tail of the dagmembers list.
1763 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1764 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1765 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1767 objlist_push_tail(&needed->obj->dldags, root);
1768 objlist_push_tail(&root->dagmembers, needed->obj);
1771 root->dag_inited = true;
1775 process_nodelete(Obj_Entry *root)
1777 const Objlist_Entry *elm;
1780 * Walk over object DAG and process every dependent object that
1781 * is marked as DF_1_NODELETE. They need to grow their own DAG,
1782 * which then should have its reference upped separately.
1784 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1785 if (elm->obj != NULL && elm->obj->z_nodelete &&
1786 !elm->obj->ref_nodel) {
1787 dbg("obj %s nodelete", elm->obj->path);
1790 elm->obj->ref_nodel = true;
1795 * Initialize the dynamic linker. The argument is the address at which
1796 * the dynamic linker has been mapped into memory. The primary task of
1797 * this function is to relocate the dynamic linker.
1800 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1802 Obj_Entry objtmp; /* Temporary rtld object */
1803 const Elf_Dyn *dyn_rpath;
1804 const Elf_Dyn *dyn_soname;
1805 const Elf_Dyn *dyn_runpath;
1807 #ifdef RTLD_INIT_PAGESIZES_EARLY
1808 /* The page size is required by the dynamic memory allocator. */
1809 init_pagesizes(aux_info);
1813 * Conjure up an Obj_Entry structure for the dynamic linker.
1815 * The "path" member can't be initialized yet because string constants
1816 * cannot yet be accessed. Below we will set it correctly.
1818 memset(&objtmp, 0, sizeof(objtmp));
1821 objtmp.mapbase = mapbase;
1823 objtmp.relocbase = mapbase;
1825 if (RTLD_IS_DYNAMIC()) {
1826 objtmp.dynamic = rtld_dynamic(&objtmp);
1827 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1828 assert(objtmp.needed == NULL);
1829 #if !defined(__mips__)
1830 /* MIPS has a bogus DT_TEXTREL. */
1831 assert(!objtmp.textrel);
1835 * Temporarily put the dynamic linker entry into the object list, so
1836 * that symbols can be found.
1839 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1842 /* Initialize the object list. */
1843 obj_tail = &obj_list;
1845 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1846 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1848 #ifndef RTLD_INIT_PAGESIZES_EARLY
1849 /* The page size is required by the dynamic memory allocator. */
1850 init_pagesizes(aux_info);
1853 if (aux_info[AT_OSRELDATE] != NULL)
1854 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1856 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1858 /* Replace the path with a dynamically allocated copy. */
1859 obj_rtld.path = xstrdup(PATH_RTLD);
1861 r_debug.r_brk = r_debug_state;
1862 r_debug.r_state = RT_CONSISTENT;
1866 * Retrieve the array of supported page sizes. The kernel provides the page
1867 * sizes in increasing order.
1870 init_pagesizes(Elf_Auxinfo **aux_info)
1872 static size_t psa[MAXPAGESIZES];
1876 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
1878 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
1879 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
1882 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
1885 /* As a fallback, retrieve the base page size. */
1886 size = sizeof(psa[0]);
1887 if (aux_info[AT_PAGESZ] != NULL) {
1888 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
1892 mib[1] = HW_PAGESIZE;
1896 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
1897 _rtld_error("sysctl for hw.pagesize(s) failed");
1903 npagesizes = size / sizeof(pagesizes[0]);
1904 /* Discard any invalid entries at the end of the array. */
1905 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
1910 * Add the init functions from a needed object list (and its recursive
1911 * needed objects) to "list". This is not used directly; it is a helper
1912 * function for initlist_add_objects(). The write lock must be held
1913 * when this function is called.
1916 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1918 /* Recursively process the successor needed objects. */
1919 if (needed->next != NULL)
1920 initlist_add_neededs(needed->next, list);
1922 /* Process the current needed object. */
1923 if (needed->obj != NULL)
1924 initlist_add_objects(needed->obj, &needed->obj->next, list);
1928 * Scan all of the DAGs rooted in the range of objects from "obj" to
1929 * "tail" and add their init functions to "list". This recurses over
1930 * the DAGs and ensure the proper init ordering such that each object's
1931 * needed libraries are initialized before the object itself. At the
1932 * same time, this function adds the objects to the global finalization
1933 * list "list_fini" in the opposite order. The write lock must be
1934 * held when this function is called.
1937 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1940 if (obj->init_scanned || obj->init_done)
1942 obj->init_scanned = true;
1944 /* Recursively process the successor objects. */
1945 if (&obj->next != tail)
1946 initlist_add_objects(obj->next, tail, list);
1948 /* Recursively process the needed objects. */
1949 if (obj->needed != NULL)
1950 initlist_add_neededs(obj->needed, list);
1951 if (obj->needed_filtees != NULL)
1952 initlist_add_neededs(obj->needed_filtees, list);
1953 if (obj->needed_aux_filtees != NULL)
1954 initlist_add_neededs(obj->needed_aux_filtees, list);
1956 /* Add the object to the init list. */
1957 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1958 obj->init_array != (Elf_Addr)NULL)
1959 objlist_push_tail(list, obj);
1961 /* Add the object to the global fini list in the reverse order. */
1962 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1963 && !obj->on_fini_list) {
1964 objlist_push_head(&list_fini, obj);
1965 obj->on_fini_list = true;
1970 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1974 free_needed_filtees(Needed_Entry *n)
1976 Needed_Entry *needed, *needed1;
1978 for (needed = n; needed != NULL; needed = needed->next) {
1979 if (needed->obj != NULL) {
1980 dlclose(needed->obj);
1984 for (needed = n; needed != NULL; needed = needed1) {
1985 needed1 = needed->next;
1991 unload_filtees(Obj_Entry *obj)
1994 free_needed_filtees(obj->needed_filtees);
1995 obj->needed_filtees = NULL;
1996 free_needed_filtees(obj->needed_aux_filtees);
1997 obj->needed_aux_filtees = NULL;
1998 obj->filtees_loaded = false;
2002 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2003 RtldLockState *lockstate)
2006 for (; needed != NULL; needed = needed->next) {
2007 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2008 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2009 RTLD_LOCAL, lockstate);
2014 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2017 lock_restart_for_upgrade(lockstate);
2018 if (!obj->filtees_loaded) {
2019 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2020 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2021 obj->filtees_loaded = true;
2026 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2030 for (; needed != NULL; needed = needed->next) {
2031 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2032 flags & ~RTLD_LO_NOLOAD);
2033 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2040 * Given a shared object, traverse its list of needed objects, and load
2041 * each of them. Returns 0 on success. Generates an error message and
2042 * returns -1 on failure.
2045 load_needed_objects(Obj_Entry *first, int flags)
2049 for (obj = first; obj != NULL; obj = obj->next) {
2050 if (process_needed(obj, obj->needed, flags) == -1)
2057 load_preload_objects(void)
2059 char *p = ld_preload;
2061 static const char delim[] = " \t:;";
2066 p += strspn(p, delim);
2067 while (*p != '\0') {
2068 size_t len = strcspn(p, delim);
2073 obj = load_object(p, -1, NULL, 0);
2075 return -1; /* XXX - cleanup */
2076 obj->z_interpose = true;
2079 p += strspn(p, delim);
2081 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2086 printable_path(const char *path)
2089 return (path == NULL ? "<unknown>" : path);
2093 * Load a shared object into memory, if it is not already loaded. The
2094 * object may be specified by name or by user-supplied file descriptor
2095 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2098 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2102 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2111 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2112 if (object_match_name(obj, name))
2116 path = find_library(name, refobj, &fd);
2124 * search_library_pathfds() opens a fresh file descriptor for the
2125 * library, so there is no need to dup().
2127 } else if (fd_u == -1) {
2129 * If we didn't find a match by pathname, or the name is not
2130 * supplied, open the file and check again by device and inode.
2131 * This avoids false mismatches caused by multiple links or ".."
2134 * To avoid a race, we open the file and use fstat() rather than
2137 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) {
2138 _rtld_error("Cannot open \"%s\"", path);
2143 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2145 _rtld_error("Cannot dup fd");
2150 if (fstat(fd, &sb) == -1) {
2151 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2156 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2157 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2159 if (obj != NULL && name != NULL) {
2160 object_add_name(obj, name);
2165 if (flags & RTLD_LO_NOLOAD) {
2171 /* First use of this object, so we must map it in */
2172 obj = do_load_object(fd, name, path, &sb, flags);
2181 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2188 * but first, make sure that environment variables haven't been
2189 * used to circumvent the noexec flag on a filesystem.
2191 if (dangerous_ld_env) {
2192 if (fstatfs(fd, &fs) != 0) {
2193 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2196 if (fs.f_flags & MNT_NOEXEC) {
2197 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2201 dbg("loading \"%s\"", printable_path(path));
2202 obj = map_object(fd, printable_path(path), sbp);
2207 * If DT_SONAME is present in the object, digest_dynamic2 already
2208 * added it to the object names.
2211 object_add_name(obj, name);
2213 digest_dynamic(obj, 0);
2214 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2215 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2216 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2218 dbg("refusing to load non-loadable \"%s\"", obj->path);
2219 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2220 munmap(obj->mapbase, obj->mapsize);
2226 obj_tail = &obj->next;
2229 linkmap_add(obj); /* for GDB & dlinfo() */
2230 max_stack_flags |= obj->stack_flags;
2232 dbg(" %p .. %p: %s", obj->mapbase,
2233 obj->mapbase + obj->mapsize - 1, obj->path);
2235 dbg(" WARNING: %s has impure text", obj->path);
2236 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2243 obj_from_addr(const void *addr)
2247 for (obj = obj_list; obj != NULL; obj = obj->next) {
2248 if (addr < (void *) obj->mapbase)
2250 if (addr < (void *) (obj->mapbase + obj->mapsize))
2259 Elf_Addr *preinit_addr;
2262 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2263 if (preinit_addr == NULL)
2266 for (index = 0; index < obj_main->preinit_array_num; index++) {
2267 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2268 dbg("calling preinit function for %s at %p", obj_main->path,
2269 (void *)preinit_addr[index]);
2270 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2271 0, 0, obj_main->path);
2272 call_init_pointer(obj_main, preinit_addr[index]);
2278 * Call the finalization functions for each of the objects in "list"
2279 * belonging to the DAG of "root" and referenced once. If NULL "root"
2280 * is specified, every finalization function will be called regardless
2281 * of the reference count and the list elements won't be freed. All of
2282 * the objects are expected to have non-NULL fini functions.
2285 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2289 Elf_Addr *fini_addr;
2292 assert(root == NULL || root->refcount == 1);
2295 * Preserve the current error message since a fini function might
2296 * call into the dynamic linker and overwrite it.
2298 saved_msg = errmsg_save();
2300 STAILQ_FOREACH(elm, list, link) {
2301 if (root != NULL && (elm->obj->refcount != 1 ||
2302 objlist_find(&root->dagmembers, elm->obj) == NULL))
2304 /* Remove object from fini list to prevent recursive invocation. */
2305 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2307 * XXX: If a dlopen() call references an object while the
2308 * fini function is in progress, we might end up trying to
2309 * unload the referenced object in dlclose() or the object
2310 * won't be unloaded although its fini function has been
2313 lock_release(rtld_bind_lock, lockstate);
2316 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2317 * When this happens, DT_FINI_ARRAY is processed first.
2319 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2320 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2321 for (index = elm->obj->fini_array_num - 1; index >= 0;
2323 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2324 dbg("calling fini function for %s at %p",
2325 elm->obj->path, (void *)fini_addr[index]);
2326 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2327 (void *)fini_addr[index], 0, 0, elm->obj->path);
2328 call_initfini_pointer(elm->obj, fini_addr[index]);
2332 if (elm->obj->fini != (Elf_Addr)NULL) {
2333 dbg("calling fini function for %s at %p", elm->obj->path,
2334 (void *)elm->obj->fini);
2335 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2336 0, 0, elm->obj->path);
2337 call_initfini_pointer(elm->obj, elm->obj->fini);
2339 wlock_acquire(rtld_bind_lock, lockstate);
2340 /* No need to free anything if process is going down. */
2344 * We must restart the list traversal after every fini call
2345 * because a dlclose() call from the fini function or from
2346 * another thread might have modified the reference counts.
2350 } while (elm != NULL);
2351 errmsg_restore(saved_msg);
2355 * Call the initialization functions for each of the objects in
2356 * "list". All of the objects are expected to have non-NULL init
2360 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2365 Elf_Addr *init_addr;
2369 * Clean init_scanned flag so that objects can be rechecked and
2370 * possibly initialized earlier if any of vectors called below
2371 * cause the change by using dlopen.
2373 for (obj = obj_list; obj != NULL; obj = obj->next)
2374 obj->init_scanned = false;
2377 * Preserve the current error message since an init function might
2378 * call into the dynamic linker and overwrite it.
2380 saved_msg = errmsg_save();
2381 STAILQ_FOREACH(elm, list, link) {
2382 if (elm->obj->init_done) /* Initialized early. */
2385 * Race: other thread might try to use this object before current
2386 * one completes the initilization. Not much can be done here
2387 * without better locking.
2389 elm->obj->init_done = true;
2390 lock_release(rtld_bind_lock, lockstate);
2393 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2394 * When this happens, DT_INIT is processed first.
2396 if (elm->obj->init != (Elf_Addr)NULL) {
2397 dbg("calling init function for %s at %p", elm->obj->path,
2398 (void *)elm->obj->init);
2399 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2400 0, 0, elm->obj->path);
2401 call_initfini_pointer(elm->obj, elm->obj->init);
2403 init_addr = (Elf_Addr *)elm->obj->init_array;
2404 if (init_addr != NULL) {
2405 for (index = 0; index < elm->obj->init_array_num; index++) {
2406 if (init_addr[index] != 0 && init_addr[index] != 1) {
2407 dbg("calling init function for %s at %p", elm->obj->path,
2408 (void *)init_addr[index]);
2409 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2410 (void *)init_addr[index], 0, 0, elm->obj->path);
2411 call_init_pointer(elm->obj, init_addr[index]);
2415 wlock_acquire(rtld_bind_lock, lockstate);
2417 errmsg_restore(saved_msg);
2421 objlist_clear(Objlist *list)
2425 while (!STAILQ_EMPTY(list)) {
2426 elm = STAILQ_FIRST(list);
2427 STAILQ_REMOVE_HEAD(list, link);
2432 static Objlist_Entry *
2433 objlist_find(Objlist *list, const Obj_Entry *obj)
2437 STAILQ_FOREACH(elm, list, link)
2438 if (elm->obj == obj)
2444 objlist_init(Objlist *list)
2450 objlist_push_head(Objlist *list, Obj_Entry *obj)
2454 elm = NEW(Objlist_Entry);
2456 STAILQ_INSERT_HEAD(list, elm, link);
2460 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2464 elm = NEW(Objlist_Entry);
2466 STAILQ_INSERT_TAIL(list, elm, link);
2470 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2472 Objlist_Entry *elm, *listelm;
2474 STAILQ_FOREACH(listelm, list, link) {
2475 if (listelm->obj == listobj)
2478 elm = NEW(Objlist_Entry);
2480 if (listelm != NULL)
2481 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2483 STAILQ_INSERT_TAIL(list, elm, link);
2487 objlist_remove(Objlist *list, Obj_Entry *obj)
2491 if ((elm = objlist_find(list, obj)) != NULL) {
2492 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2498 * Relocate dag rooted in the specified object.
2499 * Returns 0 on success, or -1 on failure.
2503 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2504 int flags, RtldLockState *lockstate)
2510 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2511 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2520 * Relocate single object.
2521 * Returns 0 on success, or -1 on failure.
2524 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2525 int flags, RtldLockState *lockstate)
2530 obj->relocated = true;
2532 dbg("relocating \"%s\"", obj->path);
2534 if (obj->symtab == NULL || obj->strtab == NULL ||
2535 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2536 _rtld_error("%s: Shared object has no run-time symbol table",
2542 /* There are relocations to the write-protected text segment. */
2543 if (mprotect(obj->mapbase, obj->textsize,
2544 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2545 _rtld_error("%s: Cannot write-enable text segment: %s",
2546 obj->path, rtld_strerror(errno));
2551 /* Process the non-PLT non-IFUNC relocations. */
2552 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2555 if (obj->textrel) { /* Re-protected the text segment. */
2556 if (mprotect(obj->mapbase, obj->textsize,
2557 PROT_READ|PROT_EXEC) == -1) {
2558 _rtld_error("%s: Cannot write-protect text segment: %s",
2559 obj->path, rtld_strerror(errno));
2564 /* Set the special PLT or GOT entries. */
2567 /* Process the PLT relocations. */
2568 if (reloc_plt(obj) == -1)
2570 /* Relocate the jump slots if we are doing immediate binding. */
2571 if (obj->bind_now || bind_now)
2572 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2576 * Process the non-PLT IFUNC relocations. The relocations are
2577 * processed in two phases, because IFUNC resolvers may
2578 * reference other symbols, which must be readily processed
2579 * before resolvers are called.
2581 if (obj->non_plt_gnu_ifunc &&
2582 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
2585 if (obj->relro_size > 0) {
2586 if (mprotect(obj->relro_page, obj->relro_size,
2588 _rtld_error("%s: Cannot enforce relro protection: %s",
2589 obj->path, rtld_strerror(errno));
2595 * Set up the magic number and version in the Obj_Entry. These
2596 * were checked in the crt1.o from the original ElfKit, so we
2597 * set them for backward compatibility.
2599 obj->magic = RTLD_MAGIC;
2600 obj->version = RTLD_VERSION;
2606 * Relocate newly-loaded shared objects. The argument is a pointer to
2607 * the Obj_Entry for the first such object. All objects from the first
2608 * to the end of the list of objects are relocated. Returns 0 on success,
2612 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2613 int flags, RtldLockState *lockstate)
2618 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2619 error = relocate_object(obj, bind_now, rtldobj, flags,
2628 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2629 * referencing STT_GNU_IFUNC symbols is postponed till the other
2630 * relocations are done. The indirect functions specified as
2631 * ifunc are allowed to call other symbols, so we need to have
2632 * objects relocated before asking for resolution from indirects.
2634 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2635 * instead of the usual lazy handling of PLT slots. It is
2636 * consistent with how GNU does it.
2639 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2640 RtldLockState *lockstate)
2642 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2644 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2645 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2651 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2652 RtldLockState *lockstate)
2656 for (obj = first; obj != NULL; obj = obj->next) {
2657 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2664 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2665 RtldLockState *lockstate)
2669 STAILQ_FOREACH(elm, list, link) {
2670 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2678 * Cleanup procedure. It will be called (by the atexit mechanism) just
2679 * before the process exits.
2684 RtldLockState lockstate;
2686 wlock_acquire(rtld_bind_lock, &lockstate);
2688 objlist_call_fini(&list_fini, NULL, &lockstate);
2689 /* No need to remove the items from the list, since we are exiting. */
2690 if (!libmap_disable)
2692 lock_release(rtld_bind_lock, &lockstate);
2696 * Iterate over a search path, translate each element, and invoke the
2697 * callback on the result.
2700 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2706 path += strspn(path, ":;");
2707 while (*path != '\0') {
2711 len = strcspn(path, ":;");
2712 trans = lm_findn(NULL, path, len);
2714 res = callback(trans, strlen(trans), arg);
2716 res = callback(path, len, arg);
2722 path += strspn(path, ":;");
2728 struct try_library_args {
2736 try_library_path(const char *dir, size_t dirlen, void *param)
2738 struct try_library_args *arg;
2741 if (*dir == '/' || trust) {
2744 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2747 pathname = arg->buffer;
2748 strncpy(pathname, dir, dirlen);
2749 pathname[dirlen] = '/';
2750 strcpy(pathname + dirlen + 1, arg->name);
2752 dbg(" Trying \"%s\"", pathname);
2753 if (access(pathname, F_OK) == 0) { /* We found it */
2754 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2755 strcpy(pathname, arg->buffer);
2763 search_library_path(const char *name, const char *path)
2766 struct try_library_args arg;
2772 arg.namelen = strlen(name);
2773 arg.buffer = xmalloc(PATH_MAX);
2774 arg.buflen = PATH_MAX;
2776 p = path_enumerate(path, try_library_path, &arg);
2785 * Finds the library with the given name using the directory descriptors
2786 * listed in the LD_LIBRARY_PATH_FDS environment variable.
2788 * Returns a freshly-opened close-on-exec file descriptor for the library,
2789 * or -1 if the library cannot be found.
2792 search_library_pathfds(const char *name, const char *path, int *fdp)
2794 char *envcopy, *fdstr, *found, *last_token;
2798 dbg("%s('%s', '%s', fdp)", __func__, name, path);
2800 /* Don't load from user-specified libdirs into setuid binaries. */
2804 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
2808 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
2809 if (name[0] == '/') {
2810 dbg("Absolute path (%s) passed to %s", name, __func__);
2815 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
2816 * copy of the path, as strtok_r rewrites separator tokens
2820 envcopy = xstrdup(path);
2821 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
2822 fdstr = strtok_r(NULL, ":", &last_token)) {
2823 dirfd = parse_libdir(fdstr);
2826 fd = openat(dirfd, name, O_RDONLY | O_CLOEXEC);
2829 len = strlen(fdstr) + strlen(name) + 3;
2830 found = xmalloc(len);
2831 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
2832 _rtld_error("error generating '%d/%s'",
2836 dbg("open('%s') => %d", found, fd);
2847 dlclose(void *handle)
2850 RtldLockState lockstate;
2852 wlock_acquire(rtld_bind_lock, &lockstate);
2853 root = dlcheck(handle);
2855 lock_release(rtld_bind_lock, &lockstate);
2858 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2861 /* Unreference the object and its dependencies. */
2862 root->dl_refcount--;
2864 if (root->refcount == 1) {
2866 * The object will be no longer referenced, so we must unload it.
2867 * First, call the fini functions.
2869 objlist_call_fini(&list_fini, root, &lockstate);
2873 /* Finish cleaning up the newly-unreferenced objects. */
2874 GDB_STATE(RT_DELETE,&root->linkmap);
2875 unload_object(root);
2876 GDB_STATE(RT_CONSISTENT,NULL);
2880 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2881 lock_release(rtld_bind_lock, &lockstate);
2888 char *msg = error_message;
2889 error_message = NULL;
2894 * This function is deprecated and has no effect.
2897 dllockinit(void *context,
2898 void *(*lock_create)(void *context),
2899 void (*rlock_acquire)(void *lock),
2900 void (*wlock_acquire)(void *lock),
2901 void (*lock_release)(void *lock),
2902 void (*lock_destroy)(void *lock),
2903 void (*context_destroy)(void *context))
2905 static void *cur_context;
2906 static void (*cur_context_destroy)(void *);
2908 /* Just destroy the context from the previous call, if necessary. */
2909 if (cur_context_destroy != NULL)
2910 cur_context_destroy(cur_context);
2911 cur_context = context;
2912 cur_context_destroy = context_destroy;
2916 dlopen(const char *name, int mode)
2919 return (rtld_dlopen(name, -1, mode));
2923 fdlopen(int fd, int mode)
2926 return (rtld_dlopen(NULL, fd, mode));
2930 rtld_dlopen(const char *name, int fd, int mode)
2932 RtldLockState lockstate;
2935 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2936 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2937 if (ld_tracing != NULL) {
2938 rlock_acquire(rtld_bind_lock, &lockstate);
2939 if (sigsetjmp(lockstate.env, 0) != 0)
2940 lock_upgrade(rtld_bind_lock, &lockstate);
2941 environ = (char **)*get_program_var_addr("environ", &lockstate);
2942 lock_release(rtld_bind_lock, &lockstate);
2944 lo_flags = RTLD_LO_DLOPEN;
2945 if (mode & RTLD_NODELETE)
2946 lo_flags |= RTLD_LO_NODELETE;
2947 if (mode & RTLD_NOLOAD)
2948 lo_flags |= RTLD_LO_NOLOAD;
2949 if (ld_tracing != NULL)
2950 lo_flags |= RTLD_LO_TRACE;
2952 return (dlopen_object(name, fd, obj_main, lo_flags,
2953 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
2957 dlopen_cleanup(Obj_Entry *obj)
2962 if (obj->refcount == 0)
2967 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2968 int mode, RtldLockState *lockstate)
2970 Obj_Entry **old_obj_tail;
2973 RtldLockState mlockstate;
2976 objlist_init(&initlist);
2978 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
2979 wlock_acquire(rtld_bind_lock, &mlockstate);
2980 lockstate = &mlockstate;
2982 GDB_STATE(RT_ADD,NULL);
2984 old_obj_tail = obj_tail;
2986 if (name == NULL && fd == -1) {
2990 obj = load_object(name, fd, refobj, lo_flags);
2995 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2996 objlist_push_tail(&list_global, obj);
2997 if (*old_obj_tail != NULL) { /* We loaded something new. */
2998 assert(*old_obj_tail == obj);
2999 result = load_needed_objects(obj,
3000 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
3004 result = rtld_verify_versions(&obj->dagmembers);
3005 if (result != -1 && ld_tracing)
3007 if (result == -1 || relocate_object_dag(obj,
3008 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3009 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3011 dlopen_cleanup(obj);
3013 } else if (lo_flags & RTLD_LO_EARLY) {
3015 * Do not call the init functions for early loaded
3016 * filtees. The image is still not initialized enough
3019 * Our object is found by the global object list and
3020 * will be ordered among all init calls done right
3021 * before transferring control to main.
3024 /* Make list of init functions to call. */
3025 initlist_add_objects(obj, &obj->next, &initlist);
3028 * Process all no_delete objects here, given them own
3029 * DAGs to prevent their dependencies from being unloaded.
3030 * This has to be done after we have loaded all of the
3031 * dependencies, so that we do not miss any.
3034 process_nodelete(obj);
3037 * Bump the reference counts for objects on this DAG. If
3038 * this is the first dlopen() call for the object that was
3039 * already loaded as a dependency, initialize the dag
3045 if ((lo_flags & RTLD_LO_TRACE) != 0)
3048 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3049 obj->z_nodelete) && !obj->ref_nodel) {
3050 dbg("obj %s nodelete", obj->path);
3052 obj->z_nodelete = obj->ref_nodel = true;
3056 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3058 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3060 if (!(lo_flags & RTLD_LO_EARLY)) {
3061 map_stacks_exec(lockstate);
3064 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3065 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3067 objlist_clear(&initlist);
3068 dlopen_cleanup(obj);
3069 if (lockstate == &mlockstate)
3070 lock_release(rtld_bind_lock, lockstate);
3074 if (!(lo_flags & RTLD_LO_EARLY)) {
3075 /* Call the init functions. */
3076 objlist_call_init(&initlist, lockstate);
3078 objlist_clear(&initlist);
3079 if (lockstate == &mlockstate)
3080 lock_release(rtld_bind_lock, lockstate);
3083 trace_loaded_objects(obj);
3084 if (lockstate == &mlockstate)
3085 lock_release(rtld_bind_lock, lockstate);
3090 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3094 const Obj_Entry *obj, *defobj;
3097 RtldLockState lockstate;
3103 symlook_init(&req, name);
3105 req.flags = flags | SYMLOOK_IN_PLT;
3106 req.lockstate = &lockstate;
3108 rlock_acquire(rtld_bind_lock, &lockstate);
3109 if (sigsetjmp(lockstate.env, 0) != 0)
3110 lock_upgrade(rtld_bind_lock, &lockstate);
3111 if (handle == NULL || handle == RTLD_NEXT ||
3112 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3114 if ((obj = obj_from_addr(retaddr)) == NULL) {
3115 _rtld_error("Cannot determine caller's shared object");
3116 lock_release(rtld_bind_lock, &lockstate);
3119 if (handle == NULL) { /* Just the caller's shared object. */
3120 res = symlook_obj(&req, obj);
3123 defobj = req.defobj_out;
3125 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3126 handle == RTLD_SELF) { /* ... caller included */
3127 if (handle == RTLD_NEXT)
3129 for (; obj != NULL; obj = obj->next) {
3130 res = symlook_obj(&req, obj);
3133 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3135 defobj = req.defobj_out;
3136 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3142 * Search the dynamic linker itself, and possibly resolve the
3143 * symbol from there. This is how the application links to
3144 * dynamic linker services such as dlopen.
3146 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3147 res = symlook_obj(&req, &obj_rtld);
3150 defobj = req.defobj_out;
3154 assert(handle == RTLD_DEFAULT);
3155 res = symlook_default(&req, obj);
3157 defobj = req.defobj_out;
3162 if ((obj = dlcheck(handle)) == NULL) {
3163 lock_release(rtld_bind_lock, &lockstate);
3167 donelist_init(&donelist);
3168 if (obj->mainprog) {
3169 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3170 res = symlook_global(&req, &donelist);
3173 defobj = req.defobj_out;
3176 * Search the dynamic linker itself, and possibly resolve the
3177 * symbol from there. This is how the application links to
3178 * dynamic linker services such as dlopen.
3180 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3181 res = symlook_obj(&req, &obj_rtld);
3184 defobj = req.defobj_out;
3189 /* Search the whole DAG rooted at the given object. */
3190 res = symlook_list(&req, &obj->dagmembers, &donelist);
3193 defobj = req.defobj_out;
3199 lock_release(rtld_bind_lock, &lockstate);
3202 * The value required by the caller is derived from the value
3203 * of the symbol. this is simply the relocated value of the
3206 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3207 return (make_function_pointer(def, defobj));
3208 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3209 return (rtld_resolve_ifunc(defobj, def));
3210 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3211 ti.ti_module = defobj->tlsindex;
3212 ti.ti_offset = def->st_value;
3213 return (__tls_get_addr(&ti));
3215 return (defobj->relocbase + def->st_value);
3218 _rtld_error("Undefined symbol \"%s\"", name);
3219 lock_release(rtld_bind_lock, &lockstate);
3224 dlsym(void *handle, const char *name)
3226 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3231 dlfunc(void *handle, const char *name)
3238 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3244 dlvsym(void *handle, const char *name, const char *version)
3248 ventry.name = version;
3250 ventry.hash = elf_hash(version);
3252 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3257 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3259 const Obj_Entry *obj;
3260 RtldLockState lockstate;
3262 rlock_acquire(rtld_bind_lock, &lockstate);
3263 obj = obj_from_addr(addr);
3265 _rtld_error("No shared object contains address");
3266 lock_release(rtld_bind_lock, &lockstate);
3269 rtld_fill_dl_phdr_info(obj, phdr_info);
3270 lock_release(rtld_bind_lock, &lockstate);
3275 dladdr(const void *addr, Dl_info *info)
3277 const Obj_Entry *obj;
3280 unsigned long symoffset;
3281 RtldLockState lockstate;
3283 rlock_acquire(rtld_bind_lock, &lockstate);
3284 obj = obj_from_addr(addr);
3286 _rtld_error("No shared object contains address");
3287 lock_release(rtld_bind_lock, &lockstate);
3290 info->dli_fname = obj->path;
3291 info->dli_fbase = obj->mapbase;
3292 info->dli_saddr = (void *)0;
3293 info->dli_sname = NULL;
3296 * Walk the symbol list looking for the symbol whose address is
3297 * closest to the address sent in.
3299 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3300 def = obj->symtab + symoffset;
3303 * For skip the symbol if st_shndx is either SHN_UNDEF or
3306 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3310 * If the symbol is greater than the specified address, or if it
3311 * is further away from addr than the current nearest symbol,
3314 symbol_addr = obj->relocbase + def->st_value;
3315 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3318 /* Update our idea of the nearest symbol. */
3319 info->dli_sname = obj->strtab + def->st_name;
3320 info->dli_saddr = symbol_addr;
3323 if (info->dli_saddr == addr)
3326 lock_release(rtld_bind_lock, &lockstate);
3331 dlinfo(void *handle, int request, void *p)
3333 const Obj_Entry *obj;
3334 RtldLockState lockstate;
3337 rlock_acquire(rtld_bind_lock, &lockstate);
3339 if (handle == NULL || handle == RTLD_SELF) {
3342 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3343 if ((obj = obj_from_addr(retaddr)) == NULL)
3344 _rtld_error("Cannot determine caller's shared object");
3346 obj = dlcheck(handle);
3349 lock_release(rtld_bind_lock, &lockstate);
3355 case RTLD_DI_LINKMAP:
3356 *((struct link_map const **)p) = &obj->linkmap;
3358 case RTLD_DI_ORIGIN:
3359 error = rtld_dirname(obj->path, p);
3362 case RTLD_DI_SERINFOSIZE:
3363 case RTLD_DI_SERINFO:
3364 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3368 _rtld_error("Invalid request %d passed to dlinfo()", request);
3372 lock_release(rtld_bind_lock, &lockstate);
3378 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3381 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3382 phdr_info->dlpi_name = obj->path;
3383 phdr_info->dlpi_phdr = obj->phdr;
3384 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3385 phdr_info->dlpi_tls_modid = obj->tlsindex;
3386 phdr_info->dlpi_tls_data = obj->tlsinit;
3387 phdr_info->dlpi_adds = obj_loads;
3388 phdr_info->dlpi_subs = obj_loads - obj_count;
3392 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3394 struct dl_phdr_info phdr_info;
3395 const Obj_Entry *obj;
3396 RtldLockState bind_lockstate, phdr_lockstate;
3399 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3400 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3404 for (obj = obj_list; obj != NULL; obj = obj->next) {
3405 rtld_fill_dl_phdr_info(obj, &phdr_info);
3406 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3411 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3412 error = callback(&phdr_info, sizeof(phdr_info), param);
3415 lock_release(rtld_bind_lock, &bind_lockstate);
3416 lock_release(rtld_phdr_lock, &phdr_lockstate);
3422 fill_search_info(const char *dir, size_t dirlen, void *param)
3424 struct fill_search_info_args *arg;
3428 if (arg->request == RTLD_DI_SERINFOSIZE) {
3429 arg->serinfo->dls_cnt ++;
3430 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3432 struct dl_serpath *s_entry;
3434 s_entry = arg->serpath;
3435 s_entry->dls_name = arg->strspace;
3436 s_entry->dls_flags = arg->flags;
3438 strncpy(arg->strspace, dir, dirlen);
3439 arg->strspace[dirlen] = '\0';
3441 arg->strspace += dirlen + 1;
3449 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3451 struct dl_serinfo _info;
3452 struct fill_search_info_args args;
3454 args.request = RTLD_DI_SERINFOSIZE;
3455 args.serinfo = &_info;
3457 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3460 path_enumerate(obj->rpath, fill_search_info, &args);
3461 path_enumerate(ld_library_path, fill_search_info, &args);
3462 path_enumerate(obj->runpath, fill_search_info, &args);
3463 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3464 if (!obj->z_nodeflib)
3465 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3468 if (request == RTLD_DI_SERINFOSIZE) {
3469 info->dls_size = _info.dls_size;
3470 info->dls_cnt = _info.dls_cnt;
3474 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3475 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3479 args.request = RTLD_DI_SERINFO;
3480 args.serinfo = info;
3481 args.serpath = &info->dls_serpath[0];
3482 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3484 args.flags = LA_SER_RUNPATH;
3485 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3488 args.flags = LA_SER_LIBPATH;
3489 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3492 args.flags = LA_SER_RUNPATH;
3493 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3496 args.flags = LA_SER_CONFIG;
3497 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3501 args.flags = LA_SER_DEFAULT;
3502 if (!obj->z_nodeflib &&
3503 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3509 rtld_dirname(const char *path, char *bname)
3513 /* Empty or NULL string gets treated as "." */
3514 if (path == NULL || *path == '\0') {
3520 /* Strip trailing slashes */
3521 endp = path + strlen(path) - 1;
3522 while (endp > path && *endp == '/')
3525 /* Find the start of the dir */
3526 while (endp > path && *endp != '/')
3529 /* Either the dir is "/" or there are no slashes */
3531 bname[0] = *endp == '/' ? '/' : '.';
3537 } while (endp > path && *endp == '/');
3540 if (endp - path + 2 > PATH_MAX)
3542 _rtld_error("Filename is too long: %s", path);
3546 strncpy(bname, path, endp - path + 1);
3547 bname[endp - path + 1] = '\0';
3552 rtld_dirname_abs(const char *path, char *base)
3554 char base_rel[PATH_MAX];
3556 if (rtld_dirname(path, base) == -1)
3560 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
3561 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
3562 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
3564 strcpy(base, base_rel);
3569 linkmap_add(Obj_Entry *obj)
3571 struct link_map *l = &obj->linkmap;
3572 struct link_map *prev;
3574 obj->linkmap.l_name = obj->path;
3575 obj->linkmap.l_addr = obj->mapbase;
3576 obj->linkmap.l_ld = obj->dynamic;
3578 /* GDB needs load offset on MIPS to use the symbols */
3579 obj->linkmap.l_offs = obj->relocbase;
3582 if (r_debug.r_map == NULL) {
3588 * Scan to the end of the list, but not past the entry for the
3589 * dynamic linker, which we want to keep at the very end.
3591 for (prev = r_debug.r_map;
3592 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3593 prev = prev->l_next)
3596 /* Link in the new entry. */
3598 l->l_next = prev->l_next;
3599 if (l->l_next != NULL)
3600 l->l_next->l_prev = l;
3605 linkmap_delete(Obj_Entry *obj)
3607 struct link_map *l = &obj->linkmap;
3609 if (l->l_prev == NULL) {
3610 if ((r_debug.r_map = l->l_next) != NULL)
3611 l->l_next->l_prev = NULL;
3615 if ((l->l_prev->l_next = l->l_next) != NULL)
3616 l->l_next->l_prev = l->l_prev;
3620 * Function for the debugger to set a breakpoint on to gain control.
3622 * The two parameters allow the debugger to easily find and determine
3623 * what the runtime loader is doing and to whom it is doing it.
3625 * When the loadhook trap is hit (r_debug_state, set at program
3626 * initialization), the arguments can be found on the stack:
3628 * +8 struct link_map *m
3629 * +4 struct r_debug *rd
3633 r_debug_state(struct r_debug* rd, struct link_map *m)
3636 * The following is a hack to force the compiler to emit calls to
3637 * this function, even when optimizing. If the function is empty,
3638 * the compiler is not obliged to emit any code for calls to it,
3639 * even when marked __noinline. However, gdb depends on those
3642 __compiler_membar();
3646 * A function called after init routines have completed. This can be used to
3647 * break before a program's entry routine is called, and can be used when
3648 * main is not available in the symbol table.
3651 _r_debug_postinit(struct link_map *m)
3654 /* See r_debug_state(). */
3655 __compiler_membar();
3659 * Get address of the pointer variable in the main program.
3660 * Prefer non-weak symbol over the weak one.
3662 static const void **
3663 get_program_var_addr(const char *name, RtldLockState *lockstate)
3668 symlook_init(&req, name);
3669 req.lockstate = lockstate;
3670 donelist_init(&donelist);
3671 if (symlook_global(&req, &donelist) != 0)
3673 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3674 return ((const void **)make_function_pointer(req.sym_out,
3676 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3677 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3679 return ((const void **)(req.defobj_out->relocbase +
3680 req.sym_out->st_value));
3684 * Set a pointer variable in the main program to the given value. This
3685 * is used to set key variables such as "environ" before any of the
3686 * init functions are called.
3689 set_program_var(const char *name, const void *value)
3693 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3694 dbg("\"%s\": *%p <-- %p", name, addr, value);
3700 * Search the global objects, including dependencies and main object,
3701 * for the given symbol.
3704 symlook_global(SymLook *req, DoneList *donelist)
3707 const Objlist_Entry *elm;
3710 symlook_init_from_req(&req1, req);
3712 /* Search all objects loaded at program start up. */
3713 if (req->defobj_out == NULL ||
3714 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3715 res = symlook_list(&req1, &list_main, donelist);
3716 if (res == 0 && (req->defobj_out == NULL ||
3717 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3718 req->sym_out = req1.sym_out;
3719 req->defobj_out = req1.defobj_out;
3720 assert(req->defobj_out != NULL);
3724 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3725 STAILQ_FOREACH(elm, &list_global, link) {
3726 if (req->defobj_out != NULL &&
3727 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3729 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3730 if (res == 0 && (req->defobj_out == NULL ||
3731 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3732 req->sym_out = req1.sym_out;
3733 req->defobj_out = req1.defobj_out;
3734 assert(req->defobj_out != NULL);
3738 return (req->sym_out != NULL ? 0 : ESRCH);
3742 * Given a symbol name in a referencing object, find the corresponding
3743 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3744 * no definition was found. Returns a pointer to the Obj_Entry of the
3745 * defining object via the reference parameter DEFOBJ_OUT.
3748 symlook_default(SymLook *req, const Obj_Entry *refobj)
3751 const Objlist_Entry *elm;
3755 donelist_init(&donelist);
3756 symlook_init_from_req(&req1, req);
3758 /* Look first in the referencing object if linked symbolically. */
3759 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3760 res = symlook_obj(&req1, refobj);
3762 req->sym_out = req1.sym_out;
3763 req->defobj_out = req1.defobj_out;
3764 assert(req->defobj_out != NULL);
3768 symlook_global(req, &donelist);
3770 /* Search all dlopened DAGs containing the referencing object. */
3771 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3772 if (req->sym_out != NULL &&
3773 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3775 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3776 if (res == 0 && (req->sym_out == NULL ||
3777 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3778 req->sym_out = req1.sym_out;
3779 req->defobj_out = req1.defobj_out;
3780 assert(req->defobj_out != NULL);
3785 * Search the dynamic linker itself, and possibly resolve the
3786 * symbol from there. This is how the application links to
3787 * dynamic linker services such as dlopen.
3789 if (req->sym_out == NULL ||
3790 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3791 res = symlook_obj(&req1, &obj_rtld);
3793 req->sym_out = req1.sym_out;
3794 req->defobj_out = req1.defobj_out;
3795 assert(req->defobj_out != NULL);
3799 return (req->sym_out != NULL ? 0 : ESRCH);
3803 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3806 const Obj_Entry *defobj;
3807 const Objlist_Entry *elm;
3813 STAILQ_FOREACH(elm, objlist, link) {
3814 if (donelist_check(dlp, elm->obj))
3816 symlook_init_from_req(&req1, req);
3817 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3818 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3820 defobj = req1.defobj_out;
3821 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3828 req->defobj_out = defobj;
3835 * Search the chain of DAGS cointed to by the given Needed_Entry
3836 * for a symbol of the given name. Each DAG is scanned completely
3837 * before advancing to the next one. Returns a pointer to the symbol,
3838 * or NULL if no definition was found.
3841 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3844 const Needed_Entry *n;
3845 const Obj_Entry *defobj;
3851 symlook_init_from_req(&req1, req);
3852 for (n = needed; n != NULL; n = n->next) {
3853 if (n->obj == NULL ||
3854 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3856 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3858 defobj = req1.defobj_out;
3859 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3865 req->defobj_out = defobj;
3872 * Search the symbol table of a single shared object for a symbol of
3873 * the given name and version, if requested. Returns a pointer to the
3874 * symbol, or NULL if no definition was found. If the object is
3875 * filter, return filtered symbol from filtee.
3877 * The symbol's hash value is passed in for efficiency reasons; that
3878 * eliminates many recomputations of the hash value.
3881 symlook_obj(SymLook *req, const Obj_Entry *obj)
3885 int flags, res, mres;
3888 * If there is at least one valid hash at this point, we prefer to
3889 * use the faster GNU version if available.
3891 if (obj->valid_hash_gnu)
3892 mres = symlook_obj1_gnu(req, obj);
3893 else if (obj->valid_hash_sysv)
3894 mres = symlook_obj1_sysv(req, obj);
3899 if (obj->needed_filtees != NULL) {
3900 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3901 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3902 donelist_init(&donelist);
3903 symlook_init_from_req(&req1, req);
3904 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3906 req->sym_out = req1.sym_out;
3907 req->defobj_out = req1.defobj_out;
3911 if (obj->needed_aux_filtees != NULL) {
3912 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3913 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3914 donelist_init(&donelist);
3915 symlook_init_from_req(&req1, req);
3916 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3918 req->sym_out = req1.sym_out;
3919 req->defobj_out = req1.defobj_out;
3927 /* Symbol match routine common to both hash functions */
3929 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3930 const unsigned long symnum)
3933 const Elf_Sym *symp;
3936 symp = obj->symtab + symnum;
3937 strp = obj->strtab + symp->st_name;
3939 switch (ELF_ST_TYPE(symp->st_info)) {
3945 if (symp->st_value == 0)
3949 if (symp->st_shndx != SHN_UNDEF)
3952 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3953 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3960 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3963 if (req->ventry == NULL) {
3964 if (obj->versyms != NULL) {
3965 verndx = VER_NDX(obj->versyms[symnum]);
3966 if (verndx > obj->vernum) {
3968 "%s: symbol %s references wrong version %d",
3969 obj->path, obj->strtab + symnum, verndx);
3973 * If we are not called from dlsym (i.e. this
3974 * is a normal relocation from unversioned
3975 * binary), accept the symbol immediately if
3976 * it happens to have first version after this
3977 * shared object became versioned. Otherwise,
3978 * if symbol is versioned and not hidden,
3979 * remember it. If it is the only symbol with
3980 * this name exported by the shared object, it
3981 * will be returned as a match by the calling
3982 * function. If symbol is global (verndx < 2)
3983 * accept it unconditionally.
3985 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3986 verndx == VER_NDX_GIVEN) {
3987 result->sym_out = symp;
3990 else if (verndx >= VER_NDX_GIVEN) {
3991 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
3993 if (result->vsymp == NULL)
3994 result->vsymp = symp;
4000 result->sym_out = symp;
4003 if (obj->versyms == NULL) {
4004 if (object_match_name(obj, req->ventry->name)) {
4005 _rtld_error("%s: object %s should provide version %s "
4006 "for symbol %s", obj_rtld.path, obj->path,
4007 req->ventry->name, obj->strtab + symnum);
4011 verndx = VER_NDX(obj->versyms[symnum]);
4012 if (verndx > obj->vernum) {
4013 _rtld_error("%s: symbol %s references wrong version %d",
4014 obj->path, obj->strtab + symnum, verndx);
4017 if (obj->vertab[verndx].hash != req->ventry->hash ||
4018 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4020 * Version does not match. Look if this is a
4021 * global symbol and if it is not hidden. If
4022 * global symbol (verndx < 2) is available,
4023 * use it. Do not return symbol if we are
4024 * called by dlvsym, because dlvsym looks for
4025 * a specific version and default one is not
4026 * what dlvsym wants.
4028 if ((req->flags & SYMLOOK_DLSYM) ||
4029 (verndx >= VER_NDX_GIVEN) ||
4030 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4034 result->sym_out = symp;
4039 * Search for symbol using SysV hash function.
4040 * obj->buckets is known not to be NULL at this point; the test for this was
4041 * performed with the obj->valid_hash_sysv assignment.
4044 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4046 unsigned long symnum;
4047 Sym_Match_Result matchres;
4049 matchres.sym_out = NULL;
4050 matchres.vsymp = NULL;
4051 matchres.vcount = 0;
4053 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4054 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4055 if (symnum >= obj->nchains)
4056 return (ESRCH); /* Bad object */
4058 if (matched_symbol(req, obj, &matchres, symnum)) {
4059 req->sym_out = matchres.sym_out;
4060 req->defobj_out = obj;
4064 if (matchres.vcount == 1) {
4065 req->sym_out = matchres.vsymp;
4066 req->defobj_out = obj;
4072 /* Search for symbol using GNU hash function */
4074 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4076 Elf_Addr bloom_word;
4077 const Elf32_Word *hashval;
4079 Sym_Match_Result matchres;
4080 unsigned int h1, h2;
4081 unsigned long symnum;
4083 matchres.sym_out = NULL;
4084 matchres.vsymp = NULL;
4085 matchres.vcount = 0;
4087 /* Pick right bitmask word from Bloom filter array */
4088 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4089 obj->maskwords_bm_gnu];
4091 /* Calculate modulus word size of gnu hash and its derivative */
4092 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4093 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4095 /* Filter out the "definitely not in set" queries */
4096 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4099 /* Locate hash chain and corresponding value element*/
4100 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4103 hashval = &obj->chain_zero_gnu[bucket];
4105 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4106 symnum = hashval - obj->chain_zero_gnu;
4107 if (matched_symbol(req, obj, &matchres, symnum)) {
4108 req->sym_out = matchres.sym_out;
4109 req->defobj_out = obj;
4113 } while ((*hashval++ & 1) == 0);
4114 if (matchres.vcount == 1) {
4115 req->sym_out = matchres.vsymp;
4116 req->defobj_out = obj;
4123 trace_loaded_objects(Obj_Entry *obj)
4125 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4128 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
4131 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
4132 fmt1 = "\t%o => %p (%x)\n";
4134 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
4135 fmt2 = "\t%o (%x)\n";
4137 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
4139 for (; obj; obj = obj->next) {
4140 Needed_Entry *needed;
4144 if (list_containers && obj->needed != NULL)
4145 rtld_printf("%s:\n", obj->path);
4146 for (needed = obj->needed; needed; needed = needed->next) {
4147 if (needed->obj != NULL) {
4148 if (needed->obj->traced && !list_containers)
4150 needed->obj->traced = true;
4151 path = needed->obj->path;
4155 name = (char *)obj->strtab + needed->name;
4156 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4158 fmt = is_lib ? fmt1 : fmt2;
4159 while ((c = *fmt++) != '\0') {
4185 rtld_putstr(main_local);
4188 rtld_putstr(obj_main->path);
4195 rtld_printf("%d", sodp->sod_major);
4198 rtld_printf("%d", sodp->sod_minor);
4205 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4218 * Unload a dlopened object and its dependencies from memory and from
4219 * our data structures. It is assumed that the DAG rooted in the
4220 * object has already been unreferenced, and that the object has a
4221 * reference count of 0.
4224 unload_object(Obj_Entry *root)
4229 assert(root->refcount == 0);
4232 * Pass over the DAG removing unreferenced objects from
4233 * appropriate lists.
4235 unlink_object(root);
4237 /* Unmap all objects that are no longer referenced. */
4238 linkp = &obj_list->next;
4239 while ((obj = *linkp) != NULL) {
4240 if (obj->refcount == 0) {
4241 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4243 dbg("unloading \"%s\"", obj->path);
4244 unload_filtees(root);
4245 munmap(obj->mapbase, obj->mapsize);
4246 linkmap_delete(obj);
4257 unlink_object(Obj_Entry *root)
4261 if (root->refcount == 0) {
4262 /* Remove the object from the RTLD_GLOBAL list. */
4263 objlist_remove(&list_global, root);
4265 /* Remove the object from all objects' DAG lists. */
4266 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4267 objlist_remove(&elm->obj->dldags, root);
4268 if (elm->obj != root)
4269 unlink_object(elm->obj);
4275 ref_dag(Obj_Entry *root)
4279 assert(root->dag_inited);
4280 STAILQ_FOREACH(elm, &root->dagmembers, link)
4281 elm->obj->refcount++;
4285 unref_dag(Obj_Entry *root)
4289 assert(root->dag_inited);
4290 STAILQ_FOREACH(elm, &root->dagmembers, link)
4291 elm->obj->refcount--;
4295 * Common code for MD __tls_get_addr().
4297 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4299 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4301 Elf_Addr *newdtv, *dtv;
4302 RtldLockState lockstate;
4306 /* Check dtv generation in case new modules have arrived */
4307 if (dtv[0] != tls_dtv_generation) {
4308 wlock_acquire(rtld_bind_lock, &lockstate);
4309 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4311 if (to_copy > tls_max_index)
4312 to_copy = tls_max_index;
4313 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4314 newdtv[0] = tls_dtv_generation;
4315 newdtv[1] = tls_max_index;
4317 lock_release(rtld_bind_lock, &lockstate);
4318 dtv = *dtvp = newdtv;
4321 /* Dynamically allocate module TLS if necessary */
4322 if (dtv[index + 1] == 0) {
4323 /* Signal safe, wlock will block out signals. */
4324 wlock_acquire(rtld_bind_lock, &lockstate);
4325 if (!dtv[index + 1])
4326 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4327 lock_release(rtld_bind_lock, &lockstate);
4329 return ((void *)(dtv[index + 1] + offset));
4333 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4338 /* Check dtv generation in case new modules have arrived */
4339 if (__predict_true(dtv[0] == tls_dtv_generation &&
4340 dtv[index + 1] != 0))
4341 return ((void *)(dtv[index + 1] + offset));
4342 return (tls_get_addr_slow(dtvp, index, offset));
4345 #if defined(__arm__) || defined(__mips__) || defined(__powerpc__)
4348 * Allocate Static TLS using the Variant I method.
4351 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4360 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4363 assert(tcbsize >= TLS_TCB_SIZE);
4364 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4365 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4367 if (oldtcb != NULL) {
4368 memcpy(tls, oldtcb, tls_static_space);
4371 /* Adjust the DTV. */
4373 for (i = 0; i < dtv[1]; i++) {
4374 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4375 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4376 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4380 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4382 dtv[0] = tls_dtv_generation;
4383 dtv[1] = tls_max_index;
4385 for (obj = objs; obj; obj = obj->next) {
4386 if (obj->tlsoffset > 0) {
4387 addr = (Elf_Addr)tls + obj->tlsoffset;
4388 if (obj->tlsinitsize > 0)
4389 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4390 if (obj->tlssize > obj->tlsinitsize)
4391 memset((void*) (addr + obj->tlsinitsize), 0,
4392 obj->tlssize - obj->tlsinitsize);
4393 dtv[obj->tlsindex + 1] = addr;
4402 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4405 Elf_Addr tlsstart, tlsend;
4408 assert(tcbsize >= TLS_TCB_SIZE);
4410 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4411 tlsend = tlsstart + tls_static_space;
4413 dtv = *(Elf_Addr **)tlsstart;
4415 for (i = 0; i < dtvsize; i++) {
4416 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4417 free((void*)dtv[i+2]);
4426 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4429 * Allocate Static TLS using the Variant II method.
4432 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4435 size_t size, ralign;
4437 Elf_Addr *dtv, *olddtv;
4438 Elf_Addr segbase, oldsegbase, addr;
4442 if (tls_static_max_align > ralign)
4443 ralign = tls_static_max_align;
4444 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4446 assert(tcbsize >= 2*sizeof(Elf_Addr));
4447 tls = malloc_aligned(size, ralign);
4448 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4450 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4451 ((Elf_Addr*)segbase)[0] = segbase;
4452 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4454 dtv[0] = tls_dtv_generation;
4455 dtv[1] = tls_max_index;
4459 * Copy the static TLS block over whole.
4461 oldsegbase = (Elf_Addr) oldtls;
4462 memcpy((void *)(segbase - tls_static_space),
4463 (const void *)(oldsegbase - tls_static_space),
4467 * If any dynamic TLS blocks have been created tls_get_addr(),
4470 olddtv = ((Elf_Addr**)oldsegbase)[1];
4471 for (i = 0; i < olddtv[1]; i++) {
4472 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4473 dtv[i+2] = olddtv[i+2];
4479 * We assume that this block was the one we created with
4480 * allocate_initial_tls().
4482 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4484 for (obj = objs; obj; obj = obj->next) {
4485 if (obj->tlsoffset) {
4486 addr = segbase - obj->tlsoffset;
4487 memset((void*) (addr + obj->tlsinitsize),
4488 0, obj->tlssize - obj->tlsinitsize);
4490 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4491 dtv[obj->tlsindex + 1] = addr;
4496 return (void*) segbase;
4500 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4503 size_t size, ralign;
4505 Elf_Addr tlsstart, tlsend;
4508 * Figure out the size of the initial TLS block so that we can
4509 * find stuff which ___tls_get_addr() allocated dynamically.
4512 if (tls_static_max_align > ralign)
4513 ralign = tls_static_max_align;
4514 size = round(tls_static_space, ralign);
4516 dtv = ((Elf_Addr**)tls)[1];
4518 tlsend = (Elf_Addr) tls;
4519 tlsstart = tlsend - size;
4520 for (i = 0; i < dtvsize; i++) {
4521 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4522 free_aligned((void *)dtv[i + 2]);
4526 free_aligned((void *)tlsstart);
4533 * Allocate TLS block for module with given index.
4536 allocate_module_tls(int index)
4541 for (obj = obj_list; obj; obj = obj->next) {
4542 if (obj->tlsindex == index)
4546 _rtld_error("Can't find module with TLS index %d", index);
4550 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4551 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4552 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4558 allocate_tls_offset(Obj_Entry *obj)
4565 if (obj->tlssize == 0) {
4566 obj->tls_done = true;
4570 if (obj->tlsindex == 1)
4571 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4573 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4574 obj->tlssize, obj->tlsalign);
4577 * If we have already fixed the size of the static TLS block, we
4578 * must stay within that size. When allocating the static TLS, we
4579 * leave a small amount of space spare to be used for dynamically
4580 * loading modules which use static TLS.
4582 if (tls_static_space != 0) {
4583 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4585 } else if (obj->tlsalign > tls_static_max_align) {
4586 tls_static_max_align = obj->tlsalign;
4589 tls_last_offset = obj->tlsoffset = off;
4590 tls_last_size = obj->tlssize;
4591 obj->tls_done = true;
4597 free_tls_offset(Obj_Entry *obj)
4601 * If we were the last thing to allocate out of the static TLS
4602 * block, we give our space back to the 'allocator'. This is a
4603 * simplistic workaround to allow libGL.so.1 to be loaded and
4604 * unloaded multiple times.
4606 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4607 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4608 tls_last_offset -= obj->tlssize;
4614 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4617 RtldLockState lockstate;
4619 wlock_acquire(rtld_bind_lock, &lockstate);
4620 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4621 lock_release(rtld_bind_lock, &lockstate);
4626 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4628 RtldLockState lockstate;
4630 wlock_acquire(rtld_bind_lock, &lockstate);
4631 free_tls(tcb, tcbsize, tcbalign);
4632 lock_release(rtld_bind_lock, &lockstate);
4636 object_add_name(Obj_Entry *obj, const char *name)
4642 entry = malloc(sizeof(Name_Entry) + len);
4644 if (entry != NULL) {
4645 strcpy(entry->name, name);
4646 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4651 object_match_name(const Obj_Entry *obj, const char *name)
4655 STAILQ_FOREACH(entry, &obj->names, link) {
4656 if (strcmp(name, entry->name) == 0)
4663 locate_dependency(const Obj_Entry *obj, const char *name)
4665 const Objlist_Entry *entry;
4666 const Needed_Entry *needed;
4668 STAILQ_FOREACH(entry, &list_main, link) {
4669 if (object_match_name(entry->obj, name))
4673 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4674 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4675 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4677 * If there is DT_NEEDED for the name we are looking for,
4678 * we are all set. Note that object might not be found if
4679 * dependency was not loaded yet, so the function can
4680 * return NULL here. This is expected and handled
4681 * properly by the caller.
4683 return (needed->obj);
4686 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4692 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4693 const Elf_Vernaux *vna)
4695 const Elf_Verdef *vd;
4696 const char *vername;
4698 vername = refobj->strtab + vna->vna_name;
4699 vd = depobj->verdef;
4701 _rtld_error("%s: version %s required by %s not defined",
4702 depobj->path, vername, refobj->path);
4706 if (vd->vd_version != VER_DEF_CURRENT) {
4707 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4708 depobj->path, vd->vd_version);
4711 if (vna->vna_hash == vd->vd_hash) {
4712 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4713 ((char *)vd + vd->vd_aux);
4714 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4717 if (vd->vd_next == 0)
4719 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4721 if (vna->vna_flags & VER_FLG_WEAK)
4723 _rtld_error("%s: version %s required by %s not found",
4724 depobj->path, vername, refobj->path);
4729 rtld_verify_object_versions(Obj_Entry *obj)
4731 const Elf_Verneed *vn;
4732 const Elf_Verdef *vd;
4733 const Elf_Verdaux *vda;
4734 const Elf_Vernaux *vna;
4735 const Obj_Entry *depobj;
4736 int maxvernum, vernum;
4738 if (obj->ver_checked)
4740 obj->ver_checked = true;
4744 * Walk over defined and required version records and figure out
4745 * max index used by any of them. Do very basic sanity checking
4749 while (vn != NULL) {
4750 if (vn->vn_version != VER_NEED_CURRENT) {
4751 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4752 obj->path, vn->vn_version);
4755 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4757 vernum = VER_NEED_IDX(vna->vna_other);
4758 if (vernum > maxvernum)
4760 if (vna->vna_next == 0)
4762 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4764 if (vn->vn_next == 0)
4766 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4770 while (vd != NULL) {
4771 if (vd->vd_version != VER_DEF_CURRENT) {
4772 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4773 obj->path, vd->vd_version);
4776 vernum = VER_DEF_IDX(vd->vd_ndx);
4777 if (vernum > maxvernum)
4779 if (vd->vd_next == 0)
4781 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4788 * Store version information in array indexable by version index.
4789 * Verify that object version requirements are satisfied along the
4792 obj->vernum = maxvernum + 1;
4793 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4796 while (vd != NULL) {
4797 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4798 vernum = VER_DEF_IDX(vd->vd_ndx);
4799 assert(vernum <= maxvernum);
4800 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4801 obj->vertab[vernum].hash = vd->vd_hash;
4802 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4803 obj->vertab[vernum].file = NULL;
4804 obj->vertab[vernum].flags = 0;
4806 if (vd->vd_next == 0)
4808 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4812 while (vn != NULL) {
4813 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4816 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4818 if (check_object_provided_version(obj, depobj, vna))
4820 vernum = VER_NEED_IDX(vna->vna_other);
4821 assert(vernum <= maxvernum);
4822 obj->vertab[vernum].hash = vna->vna_hash;
4823 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4824 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4825 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4826 VER_INFO_HIDDEN : 0;
4827 if (vna->vna_next == 0)
4829 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4831 if (vn->vn_next == 0)
4833 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4839 rtld_verify_versions(const Objlist *objlist)
4841 Objlist_Entry *entry;
4845 STAILQ_FOREACH(entry, objlist, link) {
4847 * Skip dummy objects or objects that have their version requirements
4850 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4852 if (rtld_verify_object_versions(entry->obj) == -1) {
4854 if (ld_tracing == NULL)
4858 if (rc == 0 || ld_tracing != NULL)
4859 rc = rtld_verify_object_versions(&obj_rtld);
4864 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4869 vernum = VER_NDX(obj->versyms[symnum]);
4870 if (vernum >= obj->vernum) {
4871 _rtld_error("%s: symbol %s has wrong verneed value %d",
4872 obj->path, obj->strtab + symnum, vernum);
4873 } else if (obj->vertab[vernum].hash != 0) {
4874 return &obj->vertab[vernum];
4881 _rtld_get_stack_prot(void)
4884 return (stack_prot);
4888 map_stacks_exec(RtldLockState *lockstate)
4890 void (*thr_map_stacks_exec)(void);
4892 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4894 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4895 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4896 if (thr_map_stacks_exec != NULL) {
4897 stack_prot |= PROT_EXEC;
4898 thr_map_stacks_exec();
4903 symlook_init(SymLook *dst, const char *name)
4906 bzero(dst, sizeof(*dst));
4908 dst->hash = elf_hash(name);
4909 dst->hash_gnu = gnu_hash(name);
4913 symlook_init_from_req(SymLook *dst, const SymLook *src)
4916 dst->name = src->name;
4917 dst->hash = src->hash;
4918 dst->hash_gnu = src->hash_gnu;
4919 dst->ventry = src->ventry;
4920 dst->flags = src->flags;
4921 dst->defobj_out = NULL;
4922 dst->sym_out = NULL;
4923 dst->lockstate = src->lockstate;
4928 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
4931 parse_libdir(const char *str)
4933 static const int RADIX = 10; /* XXXJA: possibly support hex? */
4940 for (c = *str; c != '\0'; c = *++str) {
4941 if (c < '0' || c > '9')
4948 /* Make sure we actually parsed something. */
4950 _rtld_error("failed to parse directory FD from '%s'", str);
4957 * Overrides for libc_pic-provided functions.
4961 __getosreldate(void)
4971 oid[1] = KERN_OSRELDATE;
4973 len = sizeof(osrel);
4974 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4975 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4987 void (*__cleanup)(void);
4988 int __isthreaded = 0;
4989 int _thread_autoinit_dummy_decl = 1;
4992 * No unresolved symbols for rtld.
4995 __pthread_cxa_finalize(struct dl_phdr_info *a)
5000 __stack_chk_fail(void)
5003 _rtld_error("stack overflow detected; terminated");
5006 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
5012 _rtld_error("buffer overflow detected; terminated");
5017 rtld_strerror(int errnum)
5020 if (errnum < 0 || errnum >= sys_nerr)
5021 return ("Unknown error");
5022 return (sys_errlist[errnum]);