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;
169 int __sys_openat(int, const char *, int, ...);
174 static char *error_message; /* Message for dlerror(), or NULL */
175 struct r_debug r_debug; /* for GDB; */
176 static bool libmap_disable; /* Disable libmap */
177 static bool ld_loadfltr; /* Immediate filters processing */
178 static char *libmap_override; /* Maps to use in addition to libmap.conf */
179 static bool trust; /* False for setuid and setgid programs */
180 static bool dangerous_ld_env; /* True if environment variables have been
181 used to affect the libraries loaded */
182 static char *ld_bind_now; /* Environment variable for immediate binding */
183 static char *ld_debug; /* Environment variable for debugging */
184 static char *ld_library_path; /* Environment variable for search path */
185 static char *ld_library_dirs; /* Environment variable for library descriptors */
186 static char *ld_preload; /* Environment variable for libraries to
188 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
189 static char *ld_tracing; /* Called from ldd to print libs */
190 static char *ld_utrace; /* Use utrace() to log events. */
191 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
192 static Obj_Entry **obj_tail; /* Link field of last object in list */
193 static Obj_Entry *obj_main; /* The main program shared object */
194 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
195 static unsigned int obj_count; /* Number of objects in obj_list */
196 static unsigned int obj_loads; /* Number of objects in obj_list */
198 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
199 STAILQ_HEAD_INITIALIZER(list_global);
200 static Objlist list_main = /* Objects loaded at program startup */
201 STAILQ_HEAD_INITIALIZER(list_main);
202 static Objlist list_fini = /* Objects needing fini() calls */
203 STAILQ_HEAD_INITIALIZER(list_fini);
205 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
207 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
209 extern Elf_Dyn _DYNAMIC;
210 #pragma weak _DYNAMIC
211 #ifndef RTLD_IS_DYNAMIC
212 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
215 int npagesizes, osreldate;
218 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
220 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
221 static int max_stack_flags;
224 * Global declarations normally provided by crt1. The dynamic linker is
225 * not built with crt1, so we have to provide them ourselves.
231 * Used to pass argc, argv to init functions.
237 * Globals to control TLS allocation.
239 size_t tls_last_offset; /* Static TLS offset of last module */
240 size_t tls_last_size; /* Static TLS size of last module */
241 size_t tls_static_space; /* Static TLS space allocated */
242 size_t tls_static_max_align;
243 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
244 int tls_max_index = 1; /* Largest module index allocated */
246 bool ld_library_path_rpath = false;
249 * Fill in a DoneList with an allocation large enough to hold all of
250 * the currently-loaded objects. Keep this as a macro since it calls
251 * alloca and we want that to occur within the scope of the caller.
253 #define donelist_init(dlp) \
254 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
255 assert((dlp)->objs != NULL), \
256 (dlp)->num_alloc = obj_count, \
259 #define UTRACE_DLOPEN_START 1
260 #define UTRACE_DLOPEN_STOP 2
261 #define UTRACE_DLCLOSE_START 3
262 #define UTRACE_DLCLOSE_STOP 4
263 #define UTRACE_LOAD_OBJECT 5
264 #define UTRACE_UNLOAD_OBJECT 6
265 #define UTRACE_ADD_RUNDEP 7
266 #define UTRACE_PRELOAD_FINISHED 8
267 #define UTRACE_INIT_CALL 9
268 #define UTRACE_FINI_CALL 10
271 char sig[4]; /* 'RTLD' */
274 void *mapbase; /* Used for 'parent' and 'init/fini' */
276 int refcnt; /* Used for 'mode' */
277 char name[MAXPATHLEN];
280 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
281 if (ld_utrace != NULL) \
282 ld_utrace_log(e, h, mb, ms, r, n); \
286 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
287 int refcnt, const char *name)
289 struct utrace_rtld ut;
297 ut.mapbase = mapbase;
298 ut.mapsize = mapsize;
300 bzero(ut.name, sizeof(ut.name));
302 strlcpy(ut.name, name, sizeof(ut.name));
303 utrace(&ut, sizeof(ut));
307 * Main entry point for dynamic linking. The first argument is the
308 * stack pointer. The stack is expected to be laid out as described
309 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
310 * Specifically, the stack pointer points to a word containing
311 * ARGC. Following that in the stack is a null-terminated sequence
312 * of pointers to argument strings. Then comes a null-terminated
313 * sequence of pointers to environment strings. Finally, there is a
314 * sequence of "auxiliary vector" entries.
316 * The second argument points to a place to store the dynamic linker's
317 * exit procedure pointer and the third to a place to store the main
320 * The return value is the main program's entry point.
323 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
325 Elf_Auxinfo *aux_info[AT_COUNT];
333 Objlist_Entry *entry;
335 Obj_Entry **preload_tail;
336 Obj_Entry *last_interposer;
338 RtldLockState lockstate;
339 char *library_path_rpath;
344 * On entry, the dynamic linker itself has not been relocated yet.
345 * Be very careful not to reference any global data until after
346 * init_rtld has returned. It is OK to reference file-scope statics
347 * and string constants, and to call static and global functions.
350 /* Find the auxiliary vector on the stack. */
353 sp += argc + 1; /* Skip over arguments and NULL terminator */
355 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
357 aux = (Elf_Auxinfo *) sp;
359 /* Digest the auxiliary vector. */
360 for (i = 0; i < AT_COUNT; i++)
362 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
363 if (auxp->a_type < AT_COUNT)
364 aux_info[auxp->a_type] = auxp;
367 /* Initialize and relocate ourselves. */
368 assert(aux_info[AT_BASE] != NULL);
369 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
371 __progname = obj_rtld.path;
372 argv0 = argv[0] != NULL ? argv[0] : "(null)";
377 if (aux_info[AT_CANARY] != NULL &&
378 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
379 i = aux_info[AT_CANARYLEN]->a_un.a_val;
380 if (i > sizeof(__stack_chk_guard))
381 i = sizeof(__stack_chk_guard);
382 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
387 len = sizeof(__stack_chk_guard);
388 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
389 len != sizeof(__stack_chk_guard)) {
390 /* If sysctl was unsuccessful, use the "terminator canary". */
391 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
392 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
393 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
394 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
398 trust = !issetugid();
400 ld_bind_now = getenv(LD_ "BIND_NOW");
402 * If the process is tainted, then we un-set the dangerous environment
403 * variables. The process will be marked as tainted until setuid(2)
404 * is called. If any child process calls setuid(2) we do not want any
405 * future processes to honor the potentially un-safe variables.
408 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
409 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBRARY_PATH_FDS") ||
410 unsetenv(LD_ "LIBMAP_DISABLE") ||
411 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
412 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) {
413 _rtld_error("environment corrupt; aborting");
417 ld_debug = getenv(LD_ "DEBUG");
418 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
419 libmap_override = getenv(LD_ "LIBMAP");
420 ld_library_path = getenv(LD_ "LIBRARY_PATH");
421 ld_library_dirs = getenv(LD_ "LIBRARY_PATH_FDS");
422 ld_preload = getenv(LD_ "PRELOAD");
423 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
424 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
425 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH");
426 if (library_path_rpath != NULL) {
427 if (library_path_rpath[0] == 'y' ||
428 library_path_rpath[0] == 'Y' ||
429 library_path_rpath[0] == '1')
430 ld_library_path_rpath = true;
432 ld_library_path_rpath = false;
434 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
435 (ld_library_path != NULL) || (ld_preload != NULL) ||
436 (ld_elf_hints_path != NULL) || ld_loadfltr;
437 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
438 ld_utrace = getenv(LD_ "UTRACE");
440 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
441 ld_elf_hints_path = _PATH_ELF_HINTS;
443 if (ld_debug != NULL && *ld_debug != '\0')
445 dbg("%s is initialized, base address = %p", __progname,
446 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
447 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
448 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
450 dbg("initializing thread locks");
454 * Load the main program, or process its program header if it is
457 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
458 int fd = aux_info[AT_EXECFD]->a_un.a_val;
459 dbg("loading main program");
460 obj_main = map_object(fd, argv0, NULL);
462 if (obj_main == NULL)
464 max_stack_flags = obj->stack_flags;
465 } else { /* Main program already loaded. */
466 const Elf_Phdr *phdr;
470 dbg("processing main program's program header");
471 assert(aux_info[AT_PHDR] != NULL);
472 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
473 assert(aux_info[AT_PHNUM] != NULL);
474 phnum = aux_info[AT_PHNUM]->a_un.a_val;
475 assert(aux_info[AT_PHENT] != NULL);
476 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
477 assert(aux_info[AT_ENTRY] != NULL);
478 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
479 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
483 if (aux_info[AT_EXECPATH] != 0) {
485 char buf[MAXPATHLEN];
487 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
488 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
489 if (kexecpath[0] == '/')
490 obj_main->path = kexecpath;
491 else if (getcwd(buf, sizeof(buf)) == NULL ||
492 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
493 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
494 obj_main->path = xstrdup(argv0);
496 obj_main->path = xstrdup(buf);
498 dbg("No AT_EXECPATH");
499 obj_main->path = xstrdup(argv0);
501 dbg("obj_main path %s", obj_main->path);
502 obj_main->mainprog = true;
504 if (aux_info[AT_STACKPROT] != NULL &&
505 aux_info[AT_STACKPROT]->a_un.a_val != 0)
506 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
510 * Get the actual dynamic linker pathname from the executable if
511 * possible. (It should always be possible.) That ensures that
512 * gdb will find the right dynamic linker even if a non-standard
515 if (obj_main->interp != NULL &&
516 strcmp(obj_main->interp, obj_rtld.path) != 0) {
518 obj_rtld.path = xstrdup(obj_main->interp);
519 __progname = obj_rtld.path;
523 digest_dynamic(obj_main, 0);
524 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
525 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
526 obj_main->dynsymcount);
528 linkmap_add(obj_main);
529 linkmap_add(&obj_rtld);
531 /* Link the main program into the list of objects. */
532 *obj_tail = obj_main;
533 obj_tail = &obj_main->next;
537 /* Initialize a fake symbol for resolving undefined weak references. */
538 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
539 sym_zero.st_shndx = SHN_UNDEF;
540 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
543 libmap_disable = (bool)lm_init(libmap_override);
545 dbg("loading LD_PRELOAD libraries");
546 if (load_preload_objects() == -1)
548 preload_tail = obj_tail;
550 dbg("loading needed objects");
551 if (load_needed_objects(obj_main, 0) == -1)
554 /* Make a list of all objects loaded at startup. */
555 last_interposer = obj_main;
556 for (obj = obj_list; obj != NULL; obj = obj->next) {
557 if (obj->z_interpose && obj != obj_main) {
558 objlist_put_after(&list_main, last_interposer, obj);
559 last_interposer = obj;
561 objlist_push_tail(&list_main, obj);
566 dbg("checking for required versions");
567 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
570 if (ld_tracing) { /* We're done */
571 trace_loaded_objects(obj_main);
575 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
576 dump_relocations(obj_main);
581 * Processing tls relocations requires having the tls offsets
582 * initialized. Prepare offsets before starting initial
583 * relocation processing.
585 dbg("initializing initial thread local storage offsets");
586 STAILQ_FOREACH(entry, &list_main, link) {
588 * Allocate all the initial objects out of the static TLS
589 * block even if they didn't ask for it.
591 allocate_tls_offset(entry->obj);
594 if (relocate_objects(obj_main,
595 ld_bind_now != NULL && *ld_bind_now != '\0',
596 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
599 dbg("doing copy relocations");
600 if (do_copy_relocations(obj_main) == -1)
603 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
604 dump_relocations(obj_main);
609 * Setup TLS for main thread. This must be done after the
610 * relocations are processed, since tls initialization section
611 * might be the subject for relocations.
613 dbg("initializing initial thread local storage");
614 allocate_initial_tls(obj_list);
616 dbg("initializing key program variables");
617 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
618 set_program_var("environ", env);
619 set_program_var("__elf_aux_vector", aux);
621 /* Make a list of init functions to call. */
622 objlist_init(&initlist);
623 initlist_add_objects(obj_list, preload_tail, &initlist);
625 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
627 map_stacks_exec(NULL);
629 dbg("resolving ifuncs");
630 if (resolve_objects_ifunc(obj_main,
631 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
635 if (!obj_main->crt_no_init) {
637 * Make sure we don't call the main program's init and fini
638 * functions for binaries linked with old crt1 which calls
641 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
642 obj_main->preinit_array = obj_main->init_array =
643 obj_main->fini_array = (Elf_Addr)NULL;
646 wlock_acquire(rtld_bind_lock, &lockstate);
647 if (obj_main->crt_no_init)
649 objlist_call_init(&initlist, &lockstate);
650 _r_debug_postinit(&obj_main->linkmap);
651 objlist_clear(&initlist);
652 dbg("loading filtees");
653 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
654 if (ld_loadfltr || obj->z_loadfltr)
655 load_filtees(obj, 0, &lockstate);
657 lock_release(rtld_bind_lock, &lockstate);
659 dbg("transferring control to program entry point = %p", obj_main->entry);
661 /* Return the exit procedure and the program entry point. */
662 *exit_proc = rtld_exit;
664 return (func_ptr_type) obj_main->entry;
668 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
673 ptr = (void *)make_function_pointer(def, obj);
674 target = ((Elf_Addr (*)(void))ptr)();
675 return ((void *)target);
679 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
683 const Obj_Entry *defobj;
686 RtldLockState lockstate;
688 rlock_acquire(rtld_bind_lock, &lockstate);
689 if (sigsetjmp(lockstate.env, 0) != 0)
690 lock_upgrade(rtld_bind_lock, &lockstate);
692 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
694 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
696 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
697 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
701 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
702 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
704 target = (Elf_Addr)(defobj->relocbase + def->st_value);
706 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
707 defobj->strtab + def->st_name, basename(obj->path),
708 (void *)target, basename(defobj->path));
711 * Write the new contents for the jmpslot. Note that depending on
712 * architecture, the value which we need to return back to the
713 * lazy binding trampoline may or may not be the target
714 * address. The value returned from reloc_jmpslot() is the value
715 * that the trampoline needs.
717 target = reloc_jmpslot(where, target, defobj, obj, rel);
718 lock_release(rtld_bind_lock, &lockstate);
723 * Error reporting function. Use it like printf. If formats the message
724 * into a buffer, and sets things up so that the next call to dlerror()
725 * will return the message.
728 _rtld_error(const char *fmt, ...)
730 static char buf[512];
734 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
740 * Return a dynamically-allocated copy of the current error message, if any.
745 return error_message == NULL ? NULL : xstrdup(error_message);
749 * Restore the current error message from a copy which was previously saved
750 * by errmsg_save(). The copy is freed.
753 errmsg_restore(char *saved_msg)
755 if (saved_msg == NULL)
756 error_message = NULL;
758 _rtld_error("%s", saved_msg);
764 basename(const char *name)
766 const char *p = strrchr(name, '/');
767 return p != NULL ? p + 1 : name;
770 static struct utsname uts;
773 origin_subst_one(char *real, const char *kw, const char *subst,
776 char *p, *p1, *res, *resp;
777 int subst_len, kw_len, subst_count, old_len, new_len;
782 * First, count the number of the keyword occurences, to
783 * preallocate the final string.
785 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
792 * If the keyword is not found, just return.
794 if (subst_count == 0)
795 return (may_free ? real : xstrdup(real));
798 * There is indeed something to substitute. Calculate the
799 * length of the resulting string, and allocate it.
801 subst_len = strlen(subst);
802 old_len = strlen(real);
803 new_len = old_len + (subst_len - kw_len) * subst_count;
804 res = xmalloc(new_len + 1);
807 * Now, execute the substitution loop.
809 for (p = real, resp = res, *resp = '\0';;) {
812 /* Copy the prefix before keyword. */
813 memcpy(resp, p, p1 - p);
815 /* Keyword replacement. */
816 memcpy(resp, subst, subst_len);
824 /* Copy to the end of string and finish. */
832 origin_subst(char *real, const char *origin_path)
834 char *res1, *res2, *res3, *res4;
836 if (uts.sysname[0] == '\0') {
837 if (uname(&uts) != 0) {
838 _rtld_error("utsname failed: %d", errno);
842 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false);
843 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true);
844 res3 = origin_subst_one(res2, "$OSREL", uts.release, true);
845 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true);
852 const char *msg = dlerror();
856 rtld_fdputstr(STDERR_FILENO, msg);
857 rtld_fdputchar(STDERR_FILENO, '\n');
862 * Process a shared object's DYNAMIC section, and save the important
863 * information in its Obj_Entry structure.
866 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
867 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
870 Needed_Entry **needed_tail = &obj->needed;
871 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
872 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
873 const Elf_Hashelt *hashtab;
874 const Elf32_Word *hashval;
875 Elf32_Word bkt, nmaskwords;
878 int plttype = DT_REL;
884 obj->bind_now = false;
885 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
886 switch (dynp->d_tag) {
889 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
893 obj->relsize = dynp->d_un.d_val;
897 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
901 obj->pltrel = (const Elf_Rel *)
902 (obj->relocbase + dynp->d_un.d_ptr);
906 obj->pltrelsize = dynp->d_un.d_val;
910 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
914 obj->relasize = dynp->d_un.d_val;
918 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
922 plttype = dynp->d_un.d_val;
923 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
927 obj->symtab = (const Elf_Sym *)
928 (obj->relocbase + dynp->d_un.d_ptr);
932 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
936 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
940 obj->strsize = dynp->d_un.d_val;
944 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
949 obj->verneednum = dynp->d_un.d_val;
953 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
958 obj->verdefnum = dynp->d_un.d_val;
962 obj->versyms = (const Elf_Versym *)(obj->relocbase +
968 hashtab = (const Elf_Hashelt *)(obj->relocbase +
970 obj->nbuckets = hashtab[0];
971 obj->nchains = hashtab[1];
972 obj->buckets = hashtab + 2;
973 obj->chains = obj->buckets + obj->nbuckets;
974 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
975 obj->buckets != NULL;
981 hashtab = (const Elf_Hashelt *)(obj->relocbase +
983 obj->nbuckets_gnu = hashtab[0];
984 obj->symndx_gnu = hashtab[1];
985 nmaskwords = hashtab[2];
986 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
987 /* Number of bitmask words is required to be power of 2 */
988 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0);
989 obj->maskwords_bm_gnu = nmaskwords - 1;
990 obj->shift2_gnu = hashtab[3];
991 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
992 obj->buckets_gnu = hashtab + 4 + bloom_size32;
993 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
995 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 &&
996 obj->buckets_gnu != NULL;
1002 Needed_Entry *nep = NEW(Needed_Entry);
1003 nep->name = dynp->d_un.d_val;
1008 needed_tail = &nep->next;
1014 Needed_Entry *nep = NEW(Needed_Entry);
1015 nep->name = dynp->d_un.d_val;
1019 *needed_filtees_tail = nep;
1020 needed_filtees_tail = &nep->next;
1026 Needed_Entry *nep = NEW(Needed_Entry);
1027 nep->name = dynp->d_un.d_val;
1031 *needed_aux_filtees_tail = nep;
1032 needed_aux_filtees_tail = &nep->next;
1037 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1041 obj->textrel = true;
1045 obj->symbolic = true;
1050 * We have to wait until later to process this, because we
1051 * might not have gotten the address of the string table yet.
1061 *dyn_runpath = dynp;
1065 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1068 case DT_PREINIT_ARRAY:
1069 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1072 case DT_PREINIT_ARRAYSZ:
1073 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1077 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1080 case DT_INIT_ARRAYSZ:
1081 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1085 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1089 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1092 case DT_FINI_ARRAYSZ:
1093 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1097 * Don't process DT_DEBUG on MIPS as the dynamic section
1098 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1103 /* XXX - not implemented yet */
1105 dbg("Filling in DT_DEBUG entry");
1106 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1111 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1112 obj->z_origin = true;
1113 if (dynp->d_un.d_val & DF_SYMBOLIC)
1114 obj->symbolic = true;
1115 if (dynp->d_un.d_val & DF_TEXTREL)
1116 obj->textrel = true;
1117 if (dynp->d_un.d_val & DF_BIND_NOW)
1118 obj->bind_now = true;
1119 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1123 case DT_MIPS_LOCAL_GOTNO:
1124 obj->local_gotno = dynp->d_un.d_val;
1127 case DT_MIPS_SYMTABNO:
1128 obj->symtabno = dynp->d_un.d_val;
1131 case DT_MIPS_GOTSYM:
1132 obj->gotsym = dynp->d_un.d_val;
1135 case DT_MIPS_RLD_MAP:
1136 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1141 if (dynp->d_un.d_val & DF_1_NOOPEN)
1142 obj->z_noopen = true;
1143 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1144 obj->z_origin = true;
1145 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1147 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1148 obj->bind_now = true;
1149 if (dynp->d_un.d_val & DF_1_NODELETE)
1150 obj->z_nodelete = true;
1151 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1152 obj->z_loadfltr = true;
1153 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1154 obj->z_interpose = true;
1155 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1156 obj->z_nodeflib = true;
1161 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1168 obj->traced = false;
1170 if (plttype == DT_RELA) {
1171 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1173 obj->pltrelasize = obj->pltrelsize;
1174 obj->pltrelsize = 0;
1177 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1178 if (obj->valid_hash_sysv)
1179 obj->dynsymcount = obj->nchains;
1180 else if (obj->valid_hash_gnu) {
1181 obj->dynsymcount = 0;
1182 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1183 if (obj->buckets_gnu[bkt] == 0)
1185 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1188 while ((*hashval++ & 1u) == 0);
1190 obj->dynsymcount += obj->symndx_gnu;
1195 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1196 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1199 if (obj->z_origin && obj->origin_path == NULL) {
1200 obj->origin_path = xmalloc(PATH_MAX);
1201 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1205 if (dyn_runpath != NULL) {
1206 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1208 obj->runpath = origin_subst(obj->runpath, obj->origin_path);
1210 else if (dyn_rpath != NULL) {
1211 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1213 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1216 if (dyn_soname != NULL)
1217 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1221 digest_dynamic(Obj_Entry *obj, int early)
1223 const Elf_Dyn *dyn_rpath;
1224 const Elf_Dyn *dyn_soname;
1225 const Elf_Dyn *dyn_runpath;
1227 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1228 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1232 * Process a shared object's program header. This is used only for the
1233 * main program, when the kernel has already loaded the main program
1234 * into memory before calling the dynamic linker. It creates and
1235 * returns an Obj_Entry structure.
1238 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1241 const Elf_Phdr *phlimit = phdr + phnum;
1243 Elf_Addr note_start, note_end;
1247 for (ph = phdr; ph < phlimit; ph++) {
1248 if (ph->p_type != PT_PHDR)
1252 obj->phsize = ph->p_memsz;
1253 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1257 obj->stack_flags = PF_X | PF_R | PF_W;
1259 for (ph = phdr; ph < phlimit; ph++) {
1260 switch (ph->p_type) {
1263 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1267 if (nsegs == 0) { /* First load segment */
1268 obj->vaddrbase = trunc_page(ph->p_vaddr);
1269 obj->mapbase = obj->vaddrbase + obj->relocbase;
1270 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1272 } else { /* Last load segment */
1273 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1280 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1285 obj->tlssize = ph->p_memsz;
1286 obj->tlsalign = ph->p_align;
1287 obj->tlsinitsize = ph->p_filesz;
1288 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1292 obj->stack_flags = ph->p_flags;
1296 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1297 obj->relro_size = round_page(ph->p_memsz);
1301 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1302 note_end = note_start + ph->p_filesz;
1303 digest_notes(obj, note_start, note_end);
1308 _rtld_error("%s: too few PT_LOAD segments", path);
1317 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1319 const Elf_Note *note;
1320 const char *note_name;
1323 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1324 note = (const Elf_Note *)((const char *)(note + 1) +
1325 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1326 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1327 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1328 note->n_descsz != sizeof(int32_t))
1330 if (note->n_type != ABI_NOTETYPE &&
1331 note->n_type != CRT_NOINIT_NOTETYPE)
1333 note_name = (const char *)(note + 1);
1334 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1335 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1337 switch (note->n_type) {
1339 /* FreeBSD osrel note */
1340 p = (uintptr_t)(note + 1);
1341 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1342 obj->osrel = *(const int32_t *)(p);
1343 dbg("note osrel %d", obj->osrel);
1345 case CRT_NOINIT_NOTETYPE:
1346 /* FreeBSD 'crt does not call init' note */
1347 obj->crt_no_init = true;
1348 dbg("note crt_no_init");
1355 dlcheck(void *handle)
1359 for (obj = obj_list; obj != NULL; obj = obj->next)
1360 if (obj == (Obj_Entry *) handle)
1363 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1364 _rtld_error("Invalid shared object handle %p", handle);
1371 * If the given object is already in the donelist, return true. Otherwise
1372 * add the object to the list and return false.
1375 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1379 for (i = 0; i < dlp->num_used; i++)
1380 if (dlp->objs[i] == obj)
1383 * Our donelist allocation should always be sufficient. But if
1384 * our threads locking isn't working properly, more shared objects
1385 * could have been loaded since we allocated the list. That should
1386 * never happen, but we'll handle it properly just in case it does.
1388 if (dlp->num_used < dlp->num_alloc)
1389 dlp->objs[dlp->num_used++] = obj;
1394 * Hash function for symbol table lookup. Don't even think about changing
1395 * this. It is specified by the System V ABI.
1398 elf_hash(const char *name)
1400 const unsigned char *p = (const unsigned char *) name;
1401 unsigned long h = 0;
1404 while (*p != '\0') {
1405 h = (h << 4) + *p++;
1406 if ((g = h & 0xf0000000) != 0)
1414 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1415 * unsigned in case it's implemented with a wider type.
1418 gnu_hash(const char *s)
1424 for (c = *s; c != '\0'; c = *++s)
1426 return (h & 0xffffffff);
1431 * Find the library with the given name, and return its full pathname.
1432 * The returned string is dynamically allocated. Generates an error
1433 * message and returns NULL if the library cannot be found.
1435 * If the second argument is non-NULL, then it refers to an already-
1436 * loaded shared object, whose library search path will be searched.
1438 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1439 * descriptor (which is close-on-exec) will be passed out via the third
1442 * The search order is:
1443 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1444 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1446 * DT_RUNPATH in the referencing file
1447 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1449 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1451 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1454 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1458 bool nodeflib, objgiven;
1460 objgiven = refobj != NULL;
1461 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1462 if (xname[0] != '/' && !trust) {
1463 _rtld_error("Absolute pathname required for shared object \"%s\"",
1467 if (objgiven && refobj->z_origin) {
1468 return (origin_subst(__DECONST(char *, xname),
1469 refobj->origin_path));
1471 return (xstrdup(xname));
1475 if (libmap_disable || !objgiven ||
1476 (name = lm_find(refobj->path, xname)) == NULL)
1477 name = (char *)xname;
1479 dbg(" Searching for \"%s\"", name);
1482 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1483 * back to pre-conforming behaviour if user requested so with
1484 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1487 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1488 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1490 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1491 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL ||
1492 (pathname = search_library_path(name, gethints(false))) != NULL ||
1493 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1496 nodeflib = objgiven ? refobj->z_nodeflib : false;
1498 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1499 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1500 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1501 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1503 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1504 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL ||
1505 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1506 (objgiven && !nodeflib &&
1507 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1511 if (objgiven && refobj->path != NULL) {
1512 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1513 name, basename(refobj->path));
1515 _rtld_error("Shared object \"%s\" not found", name);
1521 * Given a symbol number in a referencing object, find the corresponding
1522 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1523 * no definition was found. Returns a pointer to the Obj_Entry of the
1524 * defining object via the reference parameter DEFOBJ_OUT.
1527 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1528 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1529 RtldLockState *lockstate)
1533 const Obj_Entry *defobj;
1539 * If we have already found this symbol, get the information from
1542 if (symnum >= refobj->dynsymcount)
1543 return NULL; /* Bad object */
1544 if (cache != NULL && cache[symnum].sym != NULL) {
1545 *defobj_out = cache[symnum].obj;
1546 return cache[symnum].sym;
1549 ref = refobj->symtab + symnum;
1550 name = refobj->strtab + ref->st_name;
1555 * We don't have to do a full scale lookup if the symbol is local.
1556 * We know it will bind to the instance in this load module; to
1557 * which we already have a pointer (ie ref). By not doing a lookup,
1558 * we not only improve performance, but it also avoids unresolvable
1559 * symbols when local symbols are not in the hash table. This has
1560 * been seen with the ia64 toolchain.
1562 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1563 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1564 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1567 symlook_init(&req, name);
1569 req.ventry = fetch_ventry(refobj, symnum);
1570 req.lockstate = lockstate;
1571 res = symlook_default(&req, refobj);
1574 defobj = req.defobj_out;
1582 * If we found no definition and the reference is weak, treat the
1583 * symbol as having the value zero.
1585 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1591 *defobj_out = defobj;
1592 /* Record the information in the cache to avoid subsequent lookups. */
1593 if (cache != NULL) {
1594 cache[symnum].sym = def;
1595 cache[symnum].obj = defobj;
1598 if (refobj != &obj_rtld)
1599 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1605 * Return the search path from the ldconfig hints file, reading it if
1606 * necessary. If nostdlib is true, then the default search paths are
1607 * not added to result.
1609 * Returns NULL if there are problems with the hints file,
1610 * or if the search path there is empty.
1613 gethints(bool nostdlib)
1615 static char *hints, *filtered_path;
1616 struct elfhints_hdr hdr;
1617 struct fill_search_info_args sargs, hargs;
1618 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1619 struct dl_serpath *SLPpath, *hintpath;
1621 unsigned int SLPndx, hintndx, fndx, fcount;
1626 /* First call, read the hints file */
1627 if (hints == NULL) {
1628 /* Keep from trying again in case the hints file is bad. */
1631 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1633 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1634 hdr.magic != ELFHINTS_MAGIC ||
1639 p = xmalloc(hdr.dirlistlen + 1);
1640 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1641 read(fd, p, hdr.dirlistlen + 1) !=
1642 (ssize_t)hdr.dirlistlen + 1) {
1652 * If caller agreed to receive list which includes the default
1653 * paths, we are done. Otherwise, if we still did not
1654 * calculated filtered result, do it now.
1657 return (hints[0] != '\0' ? hints : NULL);
1658 if (filtered_path != NULL)
1662 * Obtain the list of all configured search paths, and the
1663 * list of the default paths.
1665 * First estimate the size of the results.
1667 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1669 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1672 sargs.request = RTLD_DI_SERINFOSIZE;
1673 sargs.serinfo = &smeta;
1674 hargs.request = RTLD_DI_SERINFOSIZE;
1675 hargs.serinfo = &hmeta;
1677 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1678 path_enumerate(p, fill_search_info, &hargs);
1680 SLPinfo = xmalloc(smeta.dls_size);
1681 hintinfo = xmalloc(hmeta.dls_size);
1684 * Next fetch both sets of paths.
1686 sargs.request = RTLD_DI_SERINFO;
1687 sargs.serinfo = SLPinfo;
1688 sargs.serpath = &SLPinfo->dls_serpath[0];
1689 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1691 hargs.request = RTLD_DI_SERINFO;
1692 hargs.serinfo = hintinfo;
1693 hargs.serpath = &hintinfo->dls_serpath[0];
1694 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1696 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1697 path_enumerate(p, fill_search_info, &hargs);
1700 * Now calculate the difference between two sets, by excluding
1701 * standard paths from the full set.
1705 filtered_path = xmalloc(hdr.dirlistlen + 1);
1706 hintpath = &hintinfo->dls_serpath[0];
1707 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1709 SLPpath = &SLPinfo->dls_serpath[0];
1711 * Check each standard path against current.
1713 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1714 /* matched, skip the path */
1715 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1723 * Not matched against any standard path, add the path
1724 * to result. Separate consequtive paths with ':'.
1727 filtered_path[fndx] = ':';
1731 flen = strlen(hintpath->dls_name);
1732 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1735 filtered_path[fndx] = '\0';
1741 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1745 init_dag(Obj_Entry *root)
1747 const Needed_Entry *needed;
1748 const Objlist_Entry *elm;
1751 if (root->dag_inited)
1753 donelist_init(&donelist);
1755 /* Root object belongs to own DAG. */
1756 objlist_push_tail(&root->dldags, root);
1757 objlist_push_tail(&root->dagmembers, root);
1758 donelist_check(&donelist, root);
1761 * Add dependencies of root object to DAG in breadth order
1762 * by exploiting the fact that each new object get added
1763 * to the tail of the dagmembers list.
1765 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1766 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1767 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1769 objlist_push_tail(&needed->obj->dldags, root);
1770 objlist_push_tail(&root->dagmembers, needed->obj);
1773 root->dag_inited = true;
1777 process_nodelete(Obj_Entry *root)
1779 const Objlist_Entry *elm;
1782 * Walk over object DAG and process every dependent object that
1783 * is marked as DF_1_NODELETE. They need to grow their own DAG,
1784 * which then should have its reference upped separately.
1786 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1787 if (elm->obj != NULL && elm->obj->z_nodelete &&
1788 !elm->obj->ref_nodel) {
1789 dbg("obj %s nodelete", elm->obj->path);
1792 elm->obj->ref_nodel = true;
1797 * Initialize the dynamic linker. The argument is the address at which
1798 * the dynamic linker has been mapped into memory. The primary task of
1799 * this function is to relocate the dynamic linker.
1802 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1804 Obj_Entry objtmp; /* Temporary rtld object */
1805 const Elf_Dyn *dyn_rpath;
1806 const Elf_Dyn *dyn_soname;
1807 const Elf_Dyn *dyn_runpath;
1809 #ifdef RTLD_INIT_PAGESIZES_EARLY
1810 /* The page size is required by the dynamic memory allocator. */
1811 init_pagesizes(aux_info);
1815 * Conjure up an Obj_Entry structure for the dynamic linker.
1817 * The "path" member can't be initialized yet because string constants
1818 * cannot yet be accessed. Below we will set it correctly.
1820 memset(&objtmp, 0, sizeof(objtmp));
1823 objtmp.mapbase = mapbase;
1825 objtmp.relocbase = mapbase;
1827 if (RTLD_IS_DYNAMIC()) {
1828 objtmp.dynamic = rtld_dynamic(&objtmp);
1829 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1830 assert(objtmp.needed == NULL);
1831 #if !defined(__mips__)
1832 /* MIPS has a bogus DT_TEXTREL. */
1833 assert(!objtmp.textrel);
1837 * Temporarily put the dynamic linker entry into the object list, so
1838 * that symbols can be found.
1841 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1844 /* Initialize the object list. */
1845 obj_tail = &obj_list;
1847 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1848 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1850 #ifndef RTLD_INIT_PAGESIZES_EARLY
1851 /* The page size is required by the dynamic memory allocator. */
1852 init_pagesizes(aux_info);
1855 if (aux_info[AT_OSRELDATE] != NULL)
1856 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1858 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1860 /* Replace the path with a dynamically allocated copy. */
1861 obj_rtld.path = xstrdup(PATH_RTLD);
1863 r_debug.r_brk = r_debug_state;
1864 r_debug.r_state = RT_CONSISTENT;
1868 * Retrieve the array of supported page sizes. The kernel provides the page
1869 * sizes in increasing order.
1872 init_pagesizes(Elf_Auxinfo **aux_info)
1874 static size_t psa[MAXPAGESIZES];
1878 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
1880 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
1881 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
1884 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
1887 /* As a fallback, retrieve the base page size. */
1888 size = sizeof(psa[0]);
1889 if (aux_info[AT_PAGESZ] != NULL) {
1890 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
1894 mib[1] = HW_PAGESIZE;
1898 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
1899 _rtld_error("sysctl for hw.pagesize(s) failed");
1905 npagesizes = size / sizeof(pagesizes[0]);
1906 /* Discard any invalid entries at the end of the array. */
1907 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
1912 * Add the init functions from a needed object list (and its recursive
1913 * needed objects) to "list". This is not used directly; it is a helper
1914 * function for initlist_add_objects(). The write lock must be held
1915 * when this function is called.
1918 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1920 /* Recursively process the successor needed objects. */
1921 if (needed->next != NULL)
1922 initlist_add_neededs(needed->next, list);
1924 /* Process the current needed object. */
1925 if (needed->obj != NULL)
1926 initlist_add_objects(needed->obj, &needed->obj->next, list);
1930 * Scan all of the DAGs rooted in the range of objects from "obj" to
1931 * "tail" and add their init functions to "list". This recurses over
1932 * the DAGs and ensure the proper init ordering such that each object's
1933 * needed libraries are initialized before the object itself. At the
1934 * same time, this function adds the objects to the global finalization
1935 * list "list_fini" in the opposite order. The write lock must be
1936 * held when this function is called.
1939 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1942 if (obj->init_scanned || obj->init_done)
1944 obj->init_scanned = true;
1946 /* Recursively process the successor objects. */
1947 if (&obj->next != tail)
1948 initlist_add_objects(obj->next, tail, list);
1950 /* Recursively process the needed objects. */
1951 if (obj->needed != NULL)
1952 initlist_add_neededs(obj->needed, list);
1953 if (obj->needed_filtees != NULL)
1954 initlist_add_neededs(obj->needed_filtees, list);
1955 if (obj->needed_aux_filtees != NULL)
1956 initlist_add_neededs(obj->needed_aux_filtees, list);
1958 /* Add the object to the init list. */
1959 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1960 obj->init_array != (Elf_Addr)NULL)
1961 objlist_push_tail(list, obj);
1963 /* Add the object to the global fini list in the reverse order. */
1964 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1965 && !obj->on_fini_list) {
1966 objlist_push_head(&list_fini, obj);
1967 obj->on_fini_list = true;
1972 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1976 free_needed_filtees(Needed_Entry *n)
1978 Needed_Entry *needed, *needed1;
1980 for (needed = n; needed != NULL; needed = needed->next) {
1981 if (needed->obj != NULL) {
1982 dlclose(needed->obj);
1986 for (needed = n; needed != NULL; needed = needed1) {
1987 needed1 = needed->next;
1993 unload_filtees(Obj_Entry *obj)
1996 free_needed_filtees(obj->needed_filtees);
1997 obj->needed_filtees = NULL;
1998 free_needed_filtees(obj->needed_aux_filtees);
1999 obj->needed_aux_filtees = NULL;
2000 obj->filtees_loaded = false;
2004 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2005 RtldLockState *lockstate)
2008 for (; needed != NULL; needed = needed->next) {
2009 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2010 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2011 RTLD_LOCAL, lockstate);
2016 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2019 lock_restart_for_upgrade(lockstate);
2020 if (!obj->filtees_loaded) {
2021 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2022 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2023 obj->filtees_loaded = true;
2028 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2032 for (; needed != NULL; needed = needed->next) {
2033 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2034 flags & ~RTLD_LO_NOLOAD);
2035 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2042 * Given a shared object, traverse its list of needed objects, and load
2043 * each of them. Returns 0 on success. Generates an error message and
2044 * returns -1 on failure.
2047 load_needed_objects(Obj_Entry *first, int flags)
2051 for (obj = first; obj != NULL; obj = obj->next) {
2052 if (process_needed(obj, obj->needed, flags) == -1)
2059 load_preload_objects(void)
2061 char *p = ld_preload;
2063 static const char delim[] = " \t:;";
2068 p += strspn(p, delim);
2069 while (*p != '\0') {
2070 size_t len = strcspn(p, delim);
2075 obj = load_object(p, -1, NULL, 0);
2077 return -1; /* XXX - cleanup */
2078 obj->z_interpose = true;
2081 p += strspn(p, delim);
2083 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2088 printable_path(const char *path)
2091 return (path == NULL ? "<unknown>" : path);
2095 * Load a shared object into memory, if it is not already loaded. The
2096 * object may be specified by name or by user-supplied file descriptor
2097 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2100 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2104 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2113 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2114 if (object_match_name(obj, name))
2118 path = find_library(name, refobj, &fd);
2126 * search_library_pathfds() opens a fresh file descriptor for the
2127 * library, so there is no need to dup().
2129 } else if (fd_u == -1) {
2131 * If we didn't find a match by pathname, or the name is not
2132 * supplied, open the file and check again by device and inode.
2133 * This avoids false mismatches caused by multiple links or ".."
2136 * To avoid a race, we open the file and use fstat() rather than
2139 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) {
2140 _rtld_error("Cannot open \"%s\"", path);
2145 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2147 _rtld_error("Cannot dup fd");
2152 if (fstat(fd, &sb) == -1) {
2153 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2158 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2159 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2161 if (obj != NULL && name != NULL) {
2162 object_add_name(obj, name);
2167 if (flags & RTLD_LO_NOLOAD) {
2173 /* First use of this object, so we must map it in */
2174 obj = do_load_object(fd, name, path, &sb, flags);
2183 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2190 * but first, make sure that environment variables haven't been
2191 * used to circumvent the noexec flag on a filesystem.
2193 if (dangerous_ld_env) {
2194 if (fstatfs(fd, &fs) != 0) {
2195 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2198 if (fs.f_flags & MNT_NOEXEC) {
2199 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2203 dbg("loading \"%s\"", printable_path(path));
2204 obj = map_object(fd, printable_path(path), sbp);
2209 * If DT_SONAME is present in the object, digest_dynamic2 already
2210 * added it to the object names.
2213 object_add_name(obj, name);
2215 digest_dynamic(obj, 0);
2216 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2217 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2218 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2220 dbg("refusing to load non-loadable \"%s\"", obj->path);
2221 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2222 munmap(obj->mapbase, obj->mapsize);
2227 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2229 obj_tail = &obj->next;
2232 linkmap_add(obj); /* for GDB & dlinfo() */
2233 max_stack_flags |= obj->stack_flags;
2235 dbg(" %p .. %p: %s", obj->mapbase,
2236 obj->mapbase + obj->mapsize - 1, obj->path);
2238 dbg(" WARNING: %s has impure text", obj->path);
2239 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2246 obj_from_addr(const void *addr)
2250 for (obj = obj_list; obj != NULL; obj = obj->next) {
2251 if (addr < (void *) obj->mapbase)
2253 if (addr < (void *) (obj->mapbase + obj->mapsize))
2262 Elf_Addr *preinit_addr;
2265 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2266 if (preinit_addr == NULL)
2269 for (index = 0; index < obj_main->preinit_array_num; index++) {
2270 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2271 dbg("calling preinit function for %s at %p", obj_main->path,
2272 (void *)preinit_addr[index]);
2273 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2274 0, 0, obj_main->path);
2275 call_init_pointer(obj_main, preinit_addr[index]);
2281 * Call the finalization functions for each of the objects in "list"
2282 * belonging to the DAG of "root" and referenced once. If NULL "root"
2283 * is specified, every finalization function will be called regardless
2284 * of the reference count and the list elements won't be freed. All of
2285 * the objects are expected to have non-NULL fini functions.
2288 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2292 Elf_Addr *fini_addr;
2295 assert(root == NULL || root->refcount == 1);
2298 * Preserve the current error message since a fini function might
2299 * call into the dynamic linker and overwrite it.
2301 saved_msg = errmsg_save();
2303 STAILQ_FOREACH(elm, list, link) {
2304 if (root != NULL && (elm->obj->refcount != 1 ||
2305 objlist_find(&root->dagmembers, elm->obj) == NULL))
2307 /* Remove object from fini list to prevent recursive invocation. */
2308 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2310 * XXX: If a dlopen() call references an object while the
2311 * fini function is in progress, we might end up trying to
2312 * unload the referenced object in dlclose() or the object
2313 * won't be unloaded although its fini function has been
2316 lock_release(rtld_bind_lock, lockstate);
2319 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2320 * When this happens, DT_FINI_ARRAY is processed first.
2322 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2323 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2324 for (index = elm->obj->fini_array_num - 1; index >= 0;
2326 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2327 dbg("calling fini function for %s at %p",
2328 elm->obj->path, (void *)fini_addr[index]);
2329 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2330 (void *)fini_addr[index], 0, 0, elm->obj->path);
2331 call_initfini_pointer(elm->obj, fini_addr[index]);
2335 if (elm->obj->fini != (Elf_Addr)NULL) {
2336 dbg("calling fini function for %s at %p", elm->obj->path,
2337 (void *)elm->obj->fini);
2338 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2339 0, 0, elm->obj->path);
2340 call_initfini_pointer(elm->obj, elm->obj->fini);
2342 wlock_acquire(rtld_bind_lock, lockstate);
2343 /* No need to free anything if process is going down. */
2347 * We must restart the list traversal after every fini call
2348 * because a dlclose() call from the fini function or from
2349 * another thread might have modified the reference counts.
2353 } while (elm != NULL);
2354 errmsg_restore(saved_msg);
2358 * Call the initialization functions for each of the objects in
2359 * "list". All of the objects are expected to have non-NULL init
2363 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2368 Elf_Addr *init_addr;
2372 * Clean init_scanned flag so that objects can be rechecked and
2373 * possibly initialized earlier if any of vectors called below
2374 * cause the change by using dlopen.
2376 for (obj = obj_list; obj != NULL; obj = obj->next)
2377 obj->init_scanned = false;
2380 * Preserve the current error message since an init function might
2381 * call into the dynamic linker and overwrite it.
2383 saved_msg = errmsg_save();
2384 STAILQ_FOREACH(elm, list, link) {
2385 if (elm->obj->init_done) /* Initialized early. */
2388 * Race: other thread might try to use this object before current
2389 * one completes the initilization. Not much can be done here
2390 * without better locking.
2392 elm->obj->init_done = true;
2393 lock_release(rtld_bind_lock, lockstate);
2396 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2397 * When this happens, DT_INIT is processed first.
2399 if (elm->obj->init != (Elf_Addr)NULL) {
2400 dbg("calling init function for %s at %p", elm->obj->path,
2401 (void *)elm->obj->init);
2402 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2403 0, 0, elm->obj->path);
2404 call_initfini_pointer(elm->obj, elm->obj->init);
2406 init_addr = (Elf_Addr *)elm->obj->init_array;
2407 if (init_addr != NULL) {
2408 for (index = 0; index < elm->obj->init_array_num; index++) {
2409 if (init_addr[index] != 0 && init_addr[index] != 1) {
2410 dbg("calling init function for %s at %p", elm->obj->path,
2411 (void *)init_addr[index]);
2412 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2413 (void *)init_addr[index], 0, 0, elm->obj->path);
2414 call_init_pointer(elm->obj, init_addr[index]);
2418 wlock_acquire(rtld_bind_lock, lockstate);
2420 errmsg_restore(saved_msg);
2424 objlist_clear(Objlist *list)
2428 while (!STAILQ_EMPTY(list)) {
2429 elm = STAILQ_FIRST(list);
2430 STAILQ_REMOVE_HEAD(list, link);
2435 static Objlist_Entry *
2436 objlist_find(Objlist *list, const Obj_Entry *obj)
2440 STAILQ_FOREACH(elm, list, link)
2441 if (elm->obj == obj)
2447 objlist_init(Objlist *list)
2453 objlist_push_head(Objlist *list, Obj_Entry *obj)
2457 elm = NEW(Objlist_Entry);
2459 STAILQ_INSERT_HEAD(list, elm, link);
2463 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2467 elm = NEW(Objlist_Entry);
2469 STAILQ_INSERT_TAIL(list, elm, link);
2473 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2475 Objlist_Entry *elm, *listelm;
2477 STAILQ_FOREACH(listelm, list, link) {
2478 if (listelm->obj == listobj)
2481 elm = NEW(Objlist_Entry);
2483 if (listelm != NULL)
2484 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2486 STAILQ_INSERT_TAIL(list, elm, link);
2490 objlist_remove(Objlist *list, Obj_Entry *obj)
2494 if ((elm = objlist_find(list, obj)) != NULL) {
2495 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2501 * Relocate dag rooted in the specified object.
2502 * Returns 0 on success, or -1 on failure.
2506 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2507 int flags, RtldLockState *lockstate)
2513 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2514 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2523 * Relocate single object.
2524 * Returns 0 on success, or -1 on failure.
2527 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2528 int flags, RtldLockState *lockstate)
2533 obj->relocated = true;
2535 dbg("relocating \"%s\"", obj->path);
2537 if (obj->symtab == NULL || obj->strtab == NULL ||
2538 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2539 _rtld_error("%s: Shared object has no run-time symbol table",
2545 /* There are relocations to the write-protected text segment. */
2546 if (mprotect(obj->mapbase, obj->textsize,
2547 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2548 _rtld_error("%s: Cannot write-enable text segment: %s",
2549 obj->path, rtld_strerror(errno));
2554 /* Process the non-PLT non-IFUNC relocations. */
2555 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2558 if (obj->textrel) { /* Re-protected the text segment. */
2559 if (mprotect(obj->mapbase, obj->textsize,
2560 PROT_READ|PROT_EXEC) == -1) {
2561 _rtld_error("%s: Cannot write-protect text segment: %s",
2562 obj->path, rtld_strerror(errno));
2567 /* Set the special PLT or GOT entries. */
2570 /* Process the PLT relocations. */
2571 if (reloc_plt(obj) == -1)
2573 /* Relocate the jump slots if we are doing immediate binding. */
2574 if (obj->bind_now || bind_now)
2575 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2579 * Process the non-PLT IFUNC relocations. The relocations are
2580 * processed in two phases, because IFUNC resolvers may
2581 * reference other symbols, which must be readily processed
2582 * before resolvers are called.
2584 if (obj->non_plt_gnu_ifunc &&
2585 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
2588 if (obj->relro_size > 0) {
2589 if (mprotect(obj->relro_page, obj->relro_size,
2591 _rtld_error("%s: Cannot enforce relro protection: %s",
2592 obj->path, rtld_strerror(errno));
2598 * Set up the magic number and version in the Obj_Entry. These
2599 * were checked in the crt1.o from the original ElfKit, so we
2600 * set them for backward compatibility.
2602 obj->magic = RTLD_MAGIC;
2603 obj->version = RTLD_VERSION;
2609 * Relocate newly-loaded shared objects. The argument is a pointer to
2610 * the Obj_Entry for the first such object. All objects from the first
2611 * to the end of the list of objects are relocated. Returns 0 on success,
2615 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2616 int flags, RtldLockState *lockstate)
2621 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2622 error = relocate_object(obj, bind_now, rtldobj, flags,
2631 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2632 * referencing STT_GNU_IFUNC symbols is postponed till the other
2633 * relocations are done. The indirect functions specified as
2634 * ifunc are allowed to call other symbols, so we need to have
2635 * objects relocated before asking for resolution from indirects.
2637 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2638 * instead of the usual lazy handling of PLT slots. It is
2639 * consistent with how GNU does it.
2642 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2643 RtldLockState *lockstate)
2645 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2647 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2648 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2654 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2655 RtldLockState *lockstate)
2659 for (obj = first; obj != NULL; obj = obj->next) {
2660 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2667 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2668 RtldLockState *lockstate)
2672 STAILQ_FOREACH(elm, list, link) {
2673 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2681 * Cleanup procedure. It will be called (by the atexit mechanism) just
2682 * before the process exits.
2687 RtldLockState lockstate;
2689 wlock_acquire(rtld_bind_lock, &lockstate);
2691 objlist_call_fini(&list_fini, NULL, &lockstate);
2692 /* No need to remove the items from the list, since we are exiting. */
2693 if (!libmap_disable)
2695 lock_release(rtld_bind_lock, &lockstate);
2699 * Iterate over a search path, translate each element, and invoke the
2700 * callback on the result.
2703 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2709 path += strspn(path, ":;");
2710 while (*path != '\0') {
2714 len = strcspn(path, ":;");
2715 trans = lm_findn(NULL, path, len);
2717 res = callback(trans, strlen(trans), arg);
2719 res = callback(path, len, arg);
2725 path += strspn(path, ":;");
2731 struct try_library_args {
2739 try_library_path(const char *dir, size_t dirlen, void *param)
2741 struct try_library_args *arg;
2744 if (*dir == '/' || trust) {
2747 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2750 pathname = arg->buffer;
2751 strncpy(pathname, dir, dirlen);
2752 pathname[dirlen] = '/';
2753 strcpy(pathname + dirlen + 1, arg->name);
2755 dbg(" Trying \"%s\"", pathname);
2756 if (access(pathname, F_OK) == 0) { /* We found it */
2757 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2758 strcpy(pathname, arg->buffer);
2766 search_library_path(const char *name, const char *path)
2769 struct try_library_args arg;
2775 arg.namelen = strlen(name);
2776 arg.buffer = xmalloc(PATH_MAX);
2777 arg.buflen = PATH_MAX;
2779 p = path_enumerate(path, try_library_path, &arg);
2788 * Finds the library with the given name using the directory descriptors
2789 * listed in the LD_LIBRARY_PATH_FDS environment variable.
2791 * Returns a freshly-opened close-on-exec file descriptor for the library,
2792 * or -1 if the library cannot be found.
2795 search_library_pathfds(const char *name, const char *path, int *fdp)
2797 char *envcopy, *fdstr, *found, *last_token;
2801 dbg("%s('%s', '%s', fdp)", __func__, name, path);
2803 /* Don't load from user-specified libdirs into setuid binaries. */
2807 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
2811 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
2812 if (name[0] == '/') {
2813 dbg("Absolute path (%s) passed to %s", name, __func__);
2818 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
2819 * copy of the path, as strtok_r rewrites separator tokens
2823 envcopy = xstrdup(path);
2824 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
2825 fdstr = strtok_r(NULL, ":", &last_token)) {
2826 dirfd = parse_libdir(fdstr);
2829 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC);
2832 len = strlen(fdstr) + strlen(name) + 3;
2833 found = xmalloc(len);
2834 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
2835 _rtld_error("error generating '%d/%s'",
2839 dbg("open('%s') => %d", found, fd);
2850 dlclose(void *handle)
2853 RtldLockState lockstate;
2855 wlock_acquire(rtld_bind_lock, &lockstate);
2856 root = dlcheck(handle);
2858 lock_release(rtld_bind_lock, &lockstate);
2861 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2864 /* Unreference the object and its dependencies. */
2865 root->dl_refcount--;
2867 if (root->refcount == 1) {
2869 * The object will be no longer referenced, so we must unload it.
2870 * First, call the fini functions.
2872 objlist_call_fini(&list_fini, root, &lockstate);
2876 /* Finish cleaning up the newly-unreferenced objects. */
2877 GDB_STATE(RT_DELETE,&root->linkmap);
2878 unload_object(root);
2879 GDB_STATE(RT_CONSISTENT,NULL);
2883 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2884 lock_release(rtld_bind_lock, &lockstate);
2891 char *msg = error_message;
2892 error_message = NULL;
2897 * This function is deprecated and has no effect.
2900 dllockinit(void *context,
2901 void *(*lock_create)(void *context),
2902 void (*rlock_acquire)(void *lock),
2903 void (*wlock_acquire)(void *lock),
2904 void (*lock_release)(void *lock),
2905 void (*lock_destroy)(void *lock),
2906 void (*context_destroy)(void *context))
2908 static void *cur_context;
2909 static void (*cur_context_destroy)(void *);
2911 /* Just destroy the context from the previous call, if necessary. */
2912 if (cur_context_destroy != NULL)
2913 cur_context_destroy(cur_context);
2914 cur_context = context;
2915 cur_context_destroy = context_destroy;
2919 dlopen(const char *name, int mode)
2922 return (rtld_dlopen(name, -1, mode));
2926 fdlopen(int fd, int mode)
2929 return (rtld_dlopen(NULL, fd, mode));
2933 rtld_dlopen(const char *name, int fd, int mode)
2935 RtldLockState lockstate;
2938 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2939 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2940 if (ld_tracing != NULL) {
2941 rlock_acquire(rtld_bind_lock, &lockstate);
2942 if (sigsetjmp(lockstate.env, 0) != 0)
2943 lock_upgrade(rtld_bind_lock, &lockstate);
2944 environ = (char **)*get_program_var_addr("environ", &lockstate);
2945 lock_release(rtld_bind_lock, &lockstate);
2947 lo_flags = RTLD_LO_DLOPEN;
2948 if (mode & RTLD_NODELETE)
2949 lo_flags |= RTLD_LO_NODELETE;
2950 if (mode & RTLD_NOLOAD)
2951 lo_flags |= RTLD_LO_NOLOAD;
2952 if (ld_tracing != NULL)
2953 lo_flags |= RTLD_LO_TRACE;
2955 return (dlopen_object(name, fd, obj_main, lo_flags,
2956 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
2960 dlopen_cleanup(Obj_Entry *obj)
2965 if (obj->refcount == 0)
2970 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2971 int mode, RtldLockState *lockstate)
2973 Obj_Entry **old_obj_tail;
2976 RtldLockState mlockstate;
2979 objlist_init(&initlist);
2981 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
2982 wlock_acquire(rtld_bind_lock, &mlockstate);
2983 lockstate = &mlockstate;
2985 GDB_STATE(RT_ADD,NULL);
2987 old_obj_tail = obj_tail;
2989 if (name == NULL && fd == -1) {
2993 obj = load_object(name, fd, refobj, lo_flags);
2998 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2999 objlist_push_tail(&list_global, obj);
3000 if (*old_obj_tail != NULL) { /* We loaded something new. */
3001 assert(*old_obj_tail == obj);
3002 result = load_needed_objects(obj,
3003 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
3007 result = rtld_verify_versions(&obj->dagmembers);
3008 if (result != -1 && ld_tracing)
3010 if (result == -1 || relocate_object_dag(obj,
3011 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3012 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3014 dlopen_cleanup(obj);
3016 } else if (lo_flags & RTLD_LO_EARLY) {
3018 * Do not call the init functions for early loaded
3019 * filtees. The image is still not initialized enough
3022 * Our object is found by the global object list and
3023 * will be ordered among all init calls done right
3024 * before transferring control to main.
3027 /* Make list of init functions to call. */
3028 initlist_add_objects(obj, &obj->next, &initlist);
3031 * Process all no_delete objects here, given them own
3032 * DAGs to prevent their dependencies from being unloaded.
3033 * This has to be done after we have loaded all of the
3034 * dependencies, so that we do not miss any.
3037 process_nodelete(obj);
3040 * Bump the reference counts for objects on this DAG. If
3041 * this is the first dlopen() call for the object that was
3042 * already loaded as a dependency, initialize the dag
3048 if ((lo_flags & RTLD_LO_TRACE) != 0)
3051 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3052 obj->z_nodelete) && !obj->ref_nodel) {
3053 dbg("obj %s nodelete", obj->path);
3055 obj->z_nodelete = obj->ref_nodel = true;
3059 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3061 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3063 if (!(lo_flags & RTLD_LO_EARLY)) {
3064 map_stacks_exec(lockstate);
3067 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3068 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3070 objlist_clear(&initlist);
3071 dlopen_cleanup(obj);
3072 if (lockstate == &mlockstate)
3073 lock_release(rtld_bind_lock, lockstate);
3077 if (!(lo_flags & RTLD_LO_EARLY)) {
3078 /* Call the init functions. */
3079 objlist_call_init(&initlist, lockstate);
3081 objlist_clear(&initlist);
3082 if (lockstate == &mlockstate)
3083 lock_release(rtld_bind_lock, lockstate);
3086 trace_loaded_objects(obj);
3087 if (lockstate == &mlockstate)
3088 lock_release(rtld_bind_lock, lockstate);
3093 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3097 const Obj_Entry *obj, *defobj;
3100 RtldLockState lockstate;
3106 symlook_init(&req, name);
3108 req.flags = flags | SYMLOOK_IN_PLT;
3109 req.lockstate = &lockstate;
3111 rlock_acquire(rtld_bind_lock, &lockstate);
3112 if (sigsetjmp(lockstate.env, 0) != 0)
3113 lock_upgrade(rtld_bind_lock, &lockstate);
3114 if (handle == NULL || handle == RTLD_NEXT ||
3115 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3117 if ((obj = obj_from_addr(retaddr)) == NULL) {
3118 _rtld_error("Cannot determine caller's shared object");
3119 lock_release(rtld_bind_lock, &lockstate);
3122 if (handle == NULL) { /* Just the caller's shared object. */
3123 res = symlook_obj(&req, obj);
3126 defobj = req.defobj_out;
3128 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3129 handle == RTLD_SELF) { /* ... caller included */
3130 if (handle == RTLD_NEXT)
3132 for (; obj != NULL; obj = obj->next) {
3133 res = symlook_obj(&req, obj);
3136 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3138 defobj = req.defobj_out;
3139 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3145 * Search the dynamic linker itself, and possibly resolve the
3146 * symbol from there. This is how the application links to
3147 * dynamic linker services such as dlopen.
3149 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3150 res = symlook_obj(&req, &obj_rtld);
3153 defobj = req.defobj_out;
3157 assert(handle == RTLD_DEFAULT);
3158 res = symlook_default(&req, obj);
3160 defobj = req.defobj_out;
3165 if ((obj = dlcheck(handle)) == NULL) {
3166 lock_release(rtld_bind_lock, &lockstate);
3170 donelist_init(&donelist);
3171 if (obj->mainprog) {
3172 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3173 res = symlook_global(&req, &donelist);
3176 defobj = req.defobj_out;
3179 * Search the dynamic linker itself, and possibly resolve the
3180 * symbol from there. This is how the application links to
3181 * dynamic linker services such as dlopen.
3183 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3184 res = symlook_obj(&req, &obj_rtld);
3187 defobj = req.defobj_out;
3192 /* Search the whole DAG rooted at the given object. */
3193 res = symlook_list(&req, &obj->dagmembers, &donelist);
3196 defobj = req.defobj_out;
3202 lock_release(rtld_bind_lock, &lockstate);
3205 * The value required by the caller is derived from the value
3206 * of the symbol. this is simply the relocated value of the
3209 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3210 return (make_function_pointer(def, defobj));
3211 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3212 return (rtld_resolve_ifunc(defobj, def));
3213 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3214 ti.ti_module = defobj->tlsindex;
3215 ti.ti_offset = def->st_value;
3216 return (__tls_get_addr(&ti));
3218 return (defobj->relocbase + def->st_value);
3221 _rtld_error("Undefined symbol \"%s\"", name);
3222 lock_release(rtld_bind_lock, &lockstate);
3227 dlsym(void *handle, const char *name)
3229 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3234 dlfunc(void *handle, const char *name)
3241 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3247 dlvsym(void *handle, const char *name, const char *version)
3251 ventry.name = version;
3253 ventry.hash = elf_hash(version);
3255 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3260 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3262 const Obj_Entry *obj;
3263 RtldLockState lockstate;
3265 rlock_acquire(rtld_bind_lock, &lockstate);
3266 obj = obj_from_addr(addr);
3268 _rtld_error("No shared object contains address");
3269 lock_release(rtld_bind_lock, &lockstate);
3272 rtld_fill_dl_phdr_info(obj, phdr_info);
3273 lock_release(rtld_bind_lock, &lockstate);
3278 dladdr(const void *addr, Dl_info *info)
3280 const Obj_Entry *obj;
3283 unsigned long symoffset;
3284 RtldLockState lockstate;
3286 rlock_acquire(rtld_bind_lock, &lockstate);
3287 obj = obj_from_addr(addr);
3289 _rtld_error("No shared object contains address");
3290 lock_release(rtld_bind_lock, &lockstate);
3293 info->dli_fname = obj->path;
3294 info->dli_fbase = obj->mapbase;
3295 info->dli_saddr = (void *)0;
3296 info->dli_sname = NULL;
3299 * Walk the symbol list looking for the symbol whose address is
3300 * closest to the address sent in.
3302 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3303 def = obj->symtab + symoffset;
3306 * For skip the symbol if st_shndx is either SHN_UNDEF or
3309 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3313 * If the symbol is greater than the specified address, or if it
3314 * is further away from addr than the current nearest symbol,
3317 symbol_addr = obj->relocbase + def->st_value;
3318 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3321 /* Update our idea of the nearest symbol. */
3322 info->dli_sname = obj->strtab + def->st_name;
3323 info->dli_saddr = symbol_addr;
3326 if (info->dli_saddr == addr)
3329 lock_release(rtld_bind_lock, &lockstate);
3334 dlinfo(void *handle, int request, void *p)
3336 const Obj_Entry *obj;
3337 RtldLockState lockstate;
3340 rlock_acquire(rtld_bind_lock, &lockstate);
3342 if (handle == NULL || handle == RTLD_SELF) {
3345 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3346 if ((obj = obj_from_addr(retaddr)) == NULL)
3347 _rtld_error("Cannot determine caller's shared object");
3349 obj = dlcheck(handle);
3352 lock_release(rtld_bind_lock, &lockstate);
3358 case RTLD_DI_LINKMAP:
3359 *((struct link_map const **)p) = &obj->linkmap;
3361 case RTLD_DI_ORIGIN:
3362 error = rtld_dirname(obj->path, p);
3365 case RTLD_DI_SERINFOSIZE:
3366 case RTLD_DI_SERINFO:
3367 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3371 _rtld_error("Invalid request %d passed to dlinfo()", request);
3375 lock_release(rtld_bind_lock, &lockstate);
3381 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3384 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3385 phdr_info->dlpi_name = obj->path;
3386 phdr_info->dlpi_phdr = obj->phdr;
3387 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3388 phdr_info->dlpi_tls_modid = obj->tlsindex;
3389 phdr_info->dlpi_tls_data = obj->tlsinit;
3390 phdr_info->dlpi_adds = obj_loads;
3391 phdr_info->dlpi_subs = obj_loads - obj_count;
3395 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3397 struct dl_phdr_info phdr_info;
3398 const Obj_Entry *obj;
3399 RtldLockState bind_lockstate, phdr_lockstate;
3402 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3403 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3407 for (obj = obj_list; obj != NULL; obj = obj->next) {
3408 rtld_fill_dl_phdr_info(obj, &phdr_info);
3409 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3414 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3415 error = callback(&phdr_info, sizeof(phdr_info), param);
3418 lock_release(rtld_bind_lock, &bind_lockstate);
3419 lock_release(rtld_phdr_lock, &phdr_lockstate);
3425 fill_search_info(const char *dir, size_t dirlen, void *param)
3427 struct fill_search_info_args *arg;
3431 if (arg->request == RTLD_DI_SERINFOSIZE) {
3432 arg->serinfo->dls_cnt ++;
3433 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3435 struct dl_serpath *s_entry;
3437 s_entry = arg->serpath;
3438 s_entry->dls_name = arg->strspace;
3439 s_entry->dls_flags = arg->flags;
3441 strncpy(arg->strspace, dir, dirlen);
3442 arg->strspace[dirlen] = '\0';
3444 arg->strspace += dirlen + 1;
3452 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3454 struct dl_serinfo _info;
3455 struct fill_search_info_args args;
3457 args.request = RTLD_DI_SERINFOSIZE;
3458 args.serinfo = &_info;
3460 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3463 path_enumerate(obj->rpath, fill_search_info, &args);
3464 path_enumerate(ld_library_path, fill_search_info, &args);
3465 path_enumerate(obj->runpath, fill_search_info, &args);
3466 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3467 if (!obj->z_nodeflib)
3468 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3471 if (request == RTLD_DI_SERINFOSIZE) {
3472 info->dls_size = _info.dls_size;
3473 info->dls_cnt = _info.dls_cnt;
3477 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3478 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3482 args.request = RTLD_DI_SERINFO;
3483 args.serinfo = info;
3484 args.serpath = &info->dls_serpath[0];
3485 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3487 args.flags = LA_SER_RUNPATH;
3488 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3491 args.flags = LA_SER_LIBPATH;
3492 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3495 args.flags = LA_SER_RUNPATH;
3496 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3499 args.flags = LA_SER_CONFIG;
3500 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3504 args.flags = LA_SER_DEFAULT;
3505 if (!obj->z_nodeflib &&
3506 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3512 rtld_dirname(const char *path, char *bname)
3516 /* Empty or NULL string gets treated as "." */
3517 if (path == NULL || *path == '\0') {
3523 /* Strip trailing slashes */
3524 endp = path + strlen(path) - 1;
3525 while (endp > path && *endp == '/')
3528 /* Find the start of the dir */
3529 while (endp > path && *endp != '/')
3532 /* Either the dir is "/" or there are no slashes */
3534 bname[0] = *endp == '/' ? '/' : '.';
3540 } while (endp > path && *endp == '/');
3543 if (endp - path + 2 > PATH_MAX)
3545 _rtld_error("Filename is too long: %s", path);
3549 strncpy(bname, path, endp - path + 1);
3550 bname[endp - path + 1] = '\0';
3555 rtld_dirname_abs(const char *path, char *base)
3557 char base_rel[PATH_MAX];
3559 if (rtld_dirname(path, base) == -1)
3563 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
3564 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
3565 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
3567 strcpy(base, base_rel);
3572 linkmap_add(Obj_Entry *obj)
3574 struct link_map *l = &obj->linkmap;
3575 struct link_map *prev;
3577 obj->linkmap.l_name = obj->path;
3578 obj->linkmap.l_addr = obj->mapbase;
3579 obj->linkmap.l_ld = obj->dynamic;
3581 /* GDB needs load offset on MIPS to use the symbols */
3582 obj->linkmap.l_offs = obj->relocbase;
3585 if (r_debug.r_map == NULL) {
3591 * Scan to the end of the list, but not past the entry for the
3592 * dynamic linker, which we want to keep at the very end.
3594 for (prev = r_debug.r_map;
3595 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3596 prev = prev->l_next)
3599 /* Link in the new entry. */
3601 l->l_next = prev->l_next;
3602 if (l->l_next != NULL)
3603 l->l_next->l_prev = l;
3608 linkmap_delete(Obj_Entry *obj)
3610 struct link_map *l = &obj->linkmap;
3612 if (l->l_prev == NULL) {
3613 if ((r_debug.r_map = l->l_next) != NULL)
3614 l->l_next->l_prev = NULL;
3618 if ((l->l_prev->l_next = l->l_next) != NULL)
3619 l->l_next->l_prev = l->l_prev;
3623 * Function for the debugger to set a breakpoint on to gain control.
3625 * The two parameters allow the debugger to easily find and determine
3626 * what the runtime loader is doing and to whom it is doing it.
3628 * When the loadhook trap is hit (r_debug_state, set at program
3629 * initialization), the arguments can be found on the stack:
3631 * +8 struct link_map *m
3632 * +4 struct r_debug *rd
3636 r_debug_state(struct r_debug* rd, struct link_map *m)
3639 * The following is a hack to force the compiler to emit calls to
3640 * this function, even when optimizing. If the function is empty,
3641 * the compiler is not obliged to emit any code for calls to it,
3642 * even when marked __noinline. However, gdb depends on those
3645 __compiler_membar();
3649 * A function called after init routines have completed. This can be used to
3650 * break before a program's entry routine is called, and can be used when
3651 * main is not available in the symbol table.
3654 _r_debug_postinit(struct link_map *m)
3657 /* See r_debug_state(). */
3658 __compiler_membar();
3662 * Get address of the pointer variable in the main program.
3663 * Prefer non-weak symbol over the weak one.
3665 static const void **
3666 get_program_var_addr(const char *name, RtldLockState *lockstate)
3671 symlook_init(&req, name);
3672 req.lockstate = lockstate;
3673 donelist_init(&donelist);
3674 if (symlook_global(&req, &donelist) != 0)
3676 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3677 return ((const void **)make_function_pointer(req.sym_out,
3679 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3680 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3682 return ((const void **)(req.defobj_out->relocbase +
3683 req.sym_out->st_value));
3687 * Set a pointer variable in the main program to the given value. This
3688 * is used to set key variables such as "environ" before any of the
3689 * init functions are called.
3692 set_program_var(const char *name, const void *value)
3696 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3697 dbg("\"%s\": *%p <-- %p", name, addr, value);
3703 * Search the global objects, including dependencies and main object,
3704 * for the given symbol.
3707 symlook_global(SymLook *req, DoneList *donelist)
3710 const Objlist_Entry *elm;
3713 symlook_init_from_req(&req1, req);
3715 /* Search all objects loaded at program start up. */
3716 if (req->defobj_out == NULL ||
3717 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3718 res = symlook_list(&req1, &list_main, donelist);
3719 if (res == 0 && (req->defobj_out == NULL ||
3720 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3721 req->sym_out = req1.sym_out;
3722 req->defobj_out = req1.defobj_out;
3723 assert(req->defobj_out != NULL);
3727 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3728 STAILQ_FOREACH(elm, &list_global, link) {
3729 if (req->defobj_out != NULL &&
3730 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3732 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3733 if (res == 0 && (req->defobj_out == NULL ||
3734 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3735 req->sym_out = req1.sym_out;
3736 req->defobj_out = req1.defobj_out;
3737 assert(req->defobj_out != NULL);
3741 return (req->sym_out != NULL ? 0 : ESRCH);
3745 * Given a symbol name in a referencing object, find the corresponding
3746 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3747 * no definition was found. Returns a pointer to the Obj_Entry of the
3748 * defining object via the reference parameter DEFOBJ_OUT.
3751 symlook_default(SymLook *req, const Obj_Entry *refobj)
3754 const Objlist_Entry *elm;
3758 donelist_init(&donelist);
3759 symlook_init_from_req(&req1, req);
3761 /* Look first in the referencing object if linked symbolically. */
3762 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3763 res = symlook_obj(&req1, refobj);
3765 req->sym_out = req1.sym_out;
3766 req->defobj_out = req1.defobj_out;
3767 assert(req->defobj_out != NULL);
3771 symlook_global(req, &donelist);
3773 /* Search all dlopened DAGs containing the referencing object. */
3774 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3775 if (req->sym_out != NULL &&
3776 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3778 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3779 if (res == 0 && (req->sym_out == NULL ||
3780 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3781 req->sym_out = req1.sym_out;
3782 req->defobj_out = req1.defobj_out;
3783 assert(req->defobj_out != NULL);
3788 * Search the dynamic linker itself, and possibly resolve the
3789 * symbol from there. This is how the application links to
3790 * dynamic linker services such as dlopen.
3792 if (req->sym_out == NULL ||
3793 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3794 res = symlook_obj(&req1, &obj_rtld);
3796 req->sym_out = req1.sym_out;
3797 req->defobj_out = req1.defobj_out;
3798 assert(req->defobj_out != NULL);
3802 return (req->sym_out != NULL ? 0 : ESRCH);
3806 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3809 const Obj_Entry *defobj;
3810 const Objlist_Entry *elm;
3816 STAILQ_FOREACH(elm, objlist, link) {
3817 if (donelist_check(dlp, elm->obj))
3819 symlook_init_from_req(&req1, req);
3820 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3821 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3823 defobj = req1.defobj_out;
3824 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3831 req->defobj_out = defobj;
3838 * Search the chain of DAGS cointed to by the given Needed_Entry
3839 * for a symbol of the given name. Each DAG is scanned completely
3840 * before advancing to the next one. Returns a pointer to the symbol,
3841 * or NULL if no definition was found.
3844 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3847 const Needed_Entry *n;
3848 const Obj_Entry *defobj;
3854 symlook_init_from_req(&req1, req);
3855 for (n = needed; n != NULL; n = n->next) {
3856 if (n->obj == NULL ||
3857 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3859 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3861 defobj = req1.defobj_out;
3862 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3868 req->defobj_out = defobj;
3875 * Search the symbol table of a single shared object for a symbol of
3876 * the given name and version, if requested. Returns a pointer to the
3877 * symbol, or NULL if no definition was found. If the object is
3878 * filter, return filtered symbol from filtee.
3880 * The symbol's hash value is passed in for efficiency reasons; that
3881 * eliminates many recomputations of the hash value.
3884 symlook_obj(SymLook *req, const Obj_Entry *obj)
3888 int flags, res, mres;
3891 * If there is at least one valid hash at this point, we prefer to
3892 * use the faster GNU version if available.
3894 if (obj->valid_hash_gnu)
3895 mres = symlook_obj1_gnu(req, obj);
3896 else if (obj->valid_hash_sysv)
3897 mres = symlook_obj1_sysv(req, obj);
3902 if (obj->needed_filtees != NULL) {
3903 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3904 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3905 donelist_init(&donelist);
3906 symlook_init_from_req(&req1, req);
3907 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3909 req->sym_out = req1.sym_out;
3910 req->defobj_out = req1.defobj_out;
3914 if (obj->needed_aux_filtees != NULL) {
3915 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3916 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3917 donelist_init(&donelist);
3918 symlook_init_from_req(&req1, req);
3919 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3921 req->sym_out = req1.sym_out;
3922 req->defobj_out = req1.defobj_out;
3930 /* Symbol match routine common to both hash functions */
3932 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3933 const unsigned long symnum)
3936 const Elf_Sym *symp;
3939 symp = obj->symtab + symnum;
3940 strp = obj->strtab + symp->st_name;
3942 switch (ELF_ST_TYPE(symp->st_info)) {
3948 if (symp->st_value == 0)
3952 if (symp->st_shndx != SHN_UNDEF)
3955 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3956 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3963 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3966 if (req->ventry == NULL) {
3967 if (obj->versyms != NULL) {
3968 verndx = VER_NDX(obj->versyms[symnum]);
3969 if (verndx > obj->vernum) {
3971 "%s: symbol %s references wrong version %d",
3972 obj->path, obj->strtab + symnum, verndx);
3976 * If we are not called from dlsym (i.e. this
3977 * is a normal relocation from unversioned
3978 * binary), accept the symbol immediately if
3979 * it happens to have first version after this
3980 * shared object became versioned. Otherwise,
3981 * if symbol is versioned and not hidden,
3982 * remember it. If it is the only symbol with
3983 * this name exported by the shared object, it
3984 * will be returned as a match by the calling
3985 * function. If symbol is global (verndx < 2)
3986 * accept it unconditionally.
3988 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3989 verndx == VER_NDX_GIVEN) {
3990 result->sym_out = symp;
3993 else if (verndx >= VER_NDX_GIVEN) {
3994 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
3996 if (result->vsymp == NULL)
3997 result->vsymp = symp;
4003 result->sym_out = symp;
4006 if (obj->versyms == NULL) {
4007 if (object_match_name(obj, req->ventry->name)) {
4008 _rtld_error("%s: object %s should provide version %s "
4009 "for symbol %s", obj_rtld.path, obj->path,
4010 req->ventry->name, obj->strtab + symnum);
4014 verndx = VER_NDX(obj->versyms[symnum]);
4015 if (verndx > obj->vernum) {
4016 _rtld_error("%s: symbol %s references wrong version %d",
4017 obj->path, obj->strtab + symnum, verndx);
4020 if (obj->vertab[verndx].hash != req->ventry->hash ||
4021 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4023 * Version does not match. Look if this is a
4024 * global symbol and if it is not hidden. If
4025 * global symbol (verndx < 2) is available,
4026 * use it. Do not return symbol if we are
4027 * called by dlvsym, because dlvsym looks for
4028 * a specific version and default one is not
4029 * what dlvsym wants.
4031 if ((req->flags & SYMLOOK_DLSYM) ||
4032 (verndx >= VER_NDX_GIVEN) ||
4033 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4037 result->sym_out = symp;
4042 * Search for symbol using SysV hash function.
4043 * obj->buckets is known not to be NULL at this point; the test for this was
4044 * performed with the obj->valid_hash_sysv assignment.
4047 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4049 unsigned long symnum;
4050 Sym_Match_Result matchres;
4052 matchres.sym_out = NULL;
4053 matchres.vsymp = NULL;
4054 matchres.vcount = 0;
4056 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4057 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4058 if (symnum >= obj->nchains)
4059 return (ESRCH); /* Bad object */
4061 if (matched_symbol(req, obj, &matchres, symnum)) {
4062 req->sym_out = matchres.sym_out;
4063 req->defobj_out = obj;
4067 if (matchres.vcount == 1) {
4068 req->sym_out = matchres.vsymp;
4069 req->defobj_out = obj;
4075 /* Search for symbol using GNU hash function */
4077 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4079 Elf_Addr bloom_word;
4080 const Elf32_Word *hashval;
4082 Sym_Match_Result matchres;
4083 unsigned int h1, h2;
4084 unsigned long symnum;
4086 matchres.sym_out = NULL;
4087 matchres.vsymp = NULL;
4088 matchres.vcount = 0;
4090 /* Pick right bitmask word from Bloom filter array */
4091 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4092 obj->maskwords_bm_gnu];
4094 /* Calculate modulus word size of gnu hash and its derivative */
4095 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4096 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4098 /* Filter out the "definitely not in set" queries */
4099 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4102 /* Locate hash chain and corresponding value element*/
4103 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4106 hashval = &obj->chain_zero_gnu[bucket];
4108 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4109 symnum = hashval - obj->chain_zero_gnu;
4110 if (matched_symbol(req, obj, &matchres, symnum)) {
4111 req->sym_out = matchres.sym_out;
4112 req->defobj_out = obj;
4116 } while ((*hashval++ & 1) == 0);
4117 if (matchres.vcount == 1) {
4118 req->sym_out = matchres.vsymp;
4119 req->defobj_out = obj;
4126 trace_loaded_objects(Obj_Entry *obj)
4128 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4131 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
4134 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
4135 fmt1 = "\t%o => %p (%x)\n";
4137 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
4138 fmt2 = "\t%o (%x)\n";
4140 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
4142 for (; obj; obj = obj->next) {
4143 Needed_Entry *needed;
4147 if (list_containers && obj->needed != NULL)
4148 rtld_printf("%s:\n", obj->path);
4149 for (needed = obj->needed; needed; needed = needed->next) {
4150 if (needed->obj != NULL) {
4151 if (needed->obj->traced && !list_containers)
4153 needed->obj->traced = true;
4154 path = needed->obj->path;
4158 name = (char *)obj->strtab + needed->name;
4159 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4161 fmt = is_lib ? fmt1 : fmt2;
4162 while ((c = *fmt++) != '\0') {
4188 rtld_putstr(main_local);
4191 rtld_putstr(obj_main->path);
4198 rtld_printf("%d", sodp->sod_major);
4201 rtld_printf("%d", sodp->sod_minor);
4208 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4221 * Unload a dlopened object and its dependencies from memory and from
4222 * our data structures. It is assumed that the DAG rooted in the
4223 * object has already been unreferenced, and that the object has a
4224 * reference count of 0.
4227 unload_object(Obj_Entry *root)
4232 assert(root->refcount == 0);
4235 * Pass over the DAG removing unreferenced objects from
4236 * appropriate lists.
4238 unlink_object(root);
4240 /* Unmap all objects that are no longer referenced. */
4241 linkp = &obj_list->next;
4242 while ((obj = *linkp) != NULL) {
4243 if (obj->refcount == 0) {
4244 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4246 dbg("unloading \"%s\"", obj->path);
4247 unload_filtees(root);
4248 munmap(obj->mapbase, obj->mapsize);
4249 linkmap_delete(obj);
4260 unlink_object(Obj_Entry *root)
4264 if (root->refcount == 0) {
4265 /* Remove the object from the RTLD_GLOBAL list. */
4266 objlist_remove(&list_global, root);
4268 /* Remove the object from all objects' DAG lists. */
4269 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4270 objlist_remove(&elm->obj->dldags, root);
4271 if (elm->obj != root)
4272 unlink_object(elm->obj);
4278 ref_dag(Obj_Entry *root)
4282 assert(root->dag_inited);
4283 STAILQ_FOREACH(elm, &root->dagmembers, link)
4284 elm->obj->refcount++;
4288 unref_dag(Obj_Entry *root)
4292 assert(root->dag_inited);
4293 STAILQ_FOREACH(elm, &root->dagmembers, link)
4294 elm->obj->refcount--;
4298 * Common code for MD __tls_get_addr().
4300 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4302 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4304 Elf_Addr *newdtv, *dtv;
4305 RtldLockState lockstate;
4309 /* Check dtv generation in case new modules have arrived */
4310 if (dtv[0] != tls_dtv_generation) {
4311 wlock_acquire(rtld_bind_lock, &lockstate);
4312 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4314 if (to_copy > tls_max_index)
4315 to_copy = tls_max_index;
4316 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4317 newdtv[0] = tls_dtv_generation;
4318 newdtv[1] = tls_max_index;
4320 lock_release(rtld_bind_lock, &lockstate);
4321 dtv = *dtvp = newdtv;
4324 /* Dynamically allocate module TLS if necessary */
4325 if (dtv[index + 1] == 0) {
4326 /* Signal safe, wlock will block out signals. */
4327 wlock_acquire(rtld_bind_lock, &lockstate);
4328 if (!dtv[index + 1])
4329 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4330 lock_release(rtld_bind_lock, &lockstate);
4332 return ((void *)(dtv[index + 1] + offset));
4336 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4341 /* Check dtv generation in case new modules have arrived */
4342 if (__predict_true(dtv[0] == tls_dtv_generation &&
4343 dtv[index + 1] != 0))
4344 return ((void *)(dtv[index + 1] + offset));
4345 return (tls_get_addr_slow(dtvp, index, offset));
4348 #if defined(__arm__) || defined(__mips__) || defined(__powerpc__)
4351 * Allocate Static TLS using the Variant I method.
4354 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4363 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4366 assert(tcbsize >= TLS_TCB_SIZE);
4367 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4368 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4370 if (oldtcb != NULL) {
4371 memcpy(tls, oldtcb, tls_static_space);
4374 /* Adjust the DTV. */
4376 for (i = 0; i < dtv[1]; i++) {
4377 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4378 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4379 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4383 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4385 dtv[0] = tls_dtv_generation;
4386 dtv[1] = tls_max_index;
4388 for (obj = objs; obj; obj = obj->next) {
4389 if (obj->tlsoffset > 0) {
4390 addr = (Elf_Addr)tls + obj->tlsoffset;
4391 if (obj->tlsinitsize > 0)
4392 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4393 if (obj->tlssize > obj->tlsinitsize)
4394 memset((void*) (addr + obj->tlsinitsize), 0,
4395 obj->tlssize - obj->tlsinitsize);
4396 dtv[obj->tlsindex + 1] = addr;
4405 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4408 Elf_Addr tlsstart, tlsend;
4411 assert(tcbsize >= TLS_TCB_SIZE);
4413 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4414 tlsend = tlsstart + tls_static_space;
4416 dtv = *(Elf_Addr **)tlsstart;
4418 for (i = 0; i < dtvsize; i++) {
4419 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4420 free((void*)dtv[i+2]);
4429 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4432 * Allocate Static TLS using the Variant II method.
4435 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4438 size_t size, ralign;
4440 Elf_Addr *dtv, *olddtv;
4441 Elf_Addr segbase, oldsegbase, addr;
4445 if (tls_static_max_align > ralign)
4446 ralign = tls_static_max_align;
4447 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4449 assert(tcbsize >= 2*sizeof(Elf_Addr));
4450 tls = malloc_aligned(size, ralign);
4451 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4453 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4454 ((Elf_Addr*)segbase)[0] = segbase;
4455 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4457 dtv[0] = tls_dtv_generation;
4458 dtv[1] = tls_max_index;
4462 * Copy the static TLS block over whole.
4464 oldsegbase = (Elf_Addr) oldtls;
4465 memcpy((void *)(segbase - tls_static_space),
4466 (const void *)(oldsegbase - tls_static_space),
4470 * If any dynamic TLS blocks have been created tls_get_addr(),
4473 olddtv = ((Elf_Addr**)oldsegbase)[1];
4474 for (i = 0; i < olddtv[1]; i++) {
4475 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4476 dtv[i+2] = olddtv[i+2];
4482 * We assume that this block was the one we created with
4483 * allocate_initial_tls().
4485 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4487 for (obj = objs; obj; obj = obj->next) {
4488 if (obj->tlsoffset) {
4489 addr = segbase - obj->tlsoffset;
4490 memset((void*) (addr + obj->tlsinitsize),
4491 0, obj->tlssize - obj->tlsinitsize);
4493 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4494 dtv[obj->tlsindex + 1] = addr;
4499 return (void*) segbase;
4503 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4506 size_t size, ralign;
4508 Elf_Addr tlsstart, tlsend;
4511 * Figure out the size of the initial TLS block so that we can
4512 * find stuff which ___tls_get_addr() allocated dynamically.
4515 if (tls_static_max_align > ralign)
4516 ralign = tls_static_max_align;
4517 size = round(tls_static_space, ralign);
4519 dtv = ((Elf_Addr**)tls)[1];
4521 tlsend = (Elf_Addr) tls;
4522 tlsstart = tlsend - size;
4523 for (i = 0; i < dtvsize; i++) {
4524 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4525 free_aligned((void *)dtv[i + 2]);
4529 free_aligned((void *)tlsstart);
4536 * Allocate TLS block for module with given index.
4539 allocate_module_tls(int index)
4544 for (obj = obj_list; obj; obj = obj->next) {
4545 if (obj->tlsindex == index)
4549 _rtld_error("Can't find module with TLS index %d", index);
4553 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4554 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4555 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4561 allocate_tls_offset(Obj_Entry *obj)
4568 if (obj->tlssize == 0) {
4569 obj->tls_done = true;
4573 if (obj->tlsindex == 1)
4574 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4576 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4577 obj->tlssize, obj->tlsalign);
4580 * If we have already fixed the size of the static TLS block, we
4581 * must stay within that size. When allocating the static TLS, we
4582 * leave a small amount of space spare to be used for dynamically
4583 * loading modules which use static TLS.
4585 if (tls_static_space != 0) {
4586 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4588 } else if (obj->tlsalign > tls_static_max_align) {
4589 tls_static_max_align = obj->tlsalign;
4592 tls_last_offset = obj->tlsoffset = off;
4593 tls_last_size = obj->tlssize;
4594 obj->tls_done = true;
4600 free_tls_offset(Obj_Entry *obj)
4604 * If we were the last thing to allocate out of the static TLS
4605 * block, we give our space back to the 'allocator'. This is a
4606 * simplistic workaround to allow libGL.so.1 to be loaded and
4607 * unloaded multiple times.
4609 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4610 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4611 tls_last_offset -= obj->tlssize;
4617 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4620 RtldLockState lockstate;
4622 wlock_acquire(rtld_bind_lock, &lockstate);
4623 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4624 lock_release(rtld_bind_lock, &lockstate);
4629 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4631 RtldLockState lockstate;
4633 wlock_acquire(rtld_bind_lock, &lockstate);
4634 free_tls(tcb, tcbsize, tcbalign);
4635 lock_release(rtld_bind_lock, &lockstate);
4639 object_add_name(Obj_Entry *obj, const char *name)
4645 entry = malloc(sizeof(Name_Entry) + len);
4647 if (entry != NULL) {
4648 strcpy(entry->name, name);
4649 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4654 object_match_name(const Obj_Entry *obj, const char *name)
4658 STAILQ_FOREACH(entry, &obj->names, link) {
4659 if (strcmp(name, entry->name) == 0)
4666 locate_dependency(const Obj_Entry *obj, const char *name)
4668 const Objlist_Entry *entry;
4669 const Needed_Entry *needed;
4671 STAILQ_FOREACH(entry, &list_main, link) {
4672 if (object_match_name(entry->obj, name))
4676 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4677 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4678 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4680 * If there is DT_NEEDED for the name we are looking for,
4681 * we are all set. Note that object might not be found if
4682 * dependency was not loaded yet, so the function can
4683 * return NULL here. This is expected and handled
4684 * properly by the caller.
4686 return (needed->obj);
4689 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4695 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4696 const Elf_Vernaux *vna)
4698 const Elf_Verdef *vd;
4699 const char *vername;
4701 vername = refobj->strtab + vna->vna_name;
4702 vd = depobj->verdef;
4704 _rtld_error("%s: version %s required by %s not defined",
4705 depobj->path, vername, refobj->path);
4709 if (vd->vd_version != VER_DEF_CURRENT) {
4710 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4711 depobj->path, vd->vd_version);
4714 if (vna->vna_hash == vd->vd_hash) {
4715 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4716 ((char *)vd + vd->vd_aux);
4717 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4720 if (vd->vd_next == 0)
4722 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4724 if (vna->vna_flags & VER_FLG_WEAK)
4726 _rtld_error("%s: version %s required by %s not found",
4727 depobj->path, vername, refobj->path);
4732 rtld_verify_object_versions(Obj_Entry *obj)
4734 const Elf_Verneed *vn;
4735 const Elf_Verdef *vd;
4736 const Elf_Verdaux *vda;
4737 const Elf_Vernaux *vna;
4738 const Obj_Entry *depobj;
4739 int maxvernum, vernum;
4741 if (obj->ver_checked)
4743 obj->ver_checked = true;
4747 * Walk over defined and required version records and figure out
4748 * max index used by any of them. Do very basic sanity checking
4752 while (vn != NULL) {
4753 if (vn->vn_version != VER_NEED_CURRENT) {
4754 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4755 obj->path, vn->vn_version);
4758 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4760 vernum = VER_NEED_IDX(vna->vna_other);
4761 if (vernum > maxvernum)
4763 if (vna->vna_next == 0)
4765 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4767 if (vn->vn_next == 0)
4769 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4773 while (vd != NULL) {
4774 if (vd->vd_version != VER_DEF_CURRENT) {
4775 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4776 obj->path, vd->vd_version);
4779 vernum = VER_DEF_IDX(vd->vd_ndx);
4780 if (vernum > maxvernum)
4782 if (vd->vd_next == 0)
4784 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4791 * Store version information in array indexable by version index.
4792 * Verify that object version requirements are satisfied along the
4795 obj->vernum = maxvernum + 1;
4796 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4799 while (vd != NULL) {
4800 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4801 vernum = VER_DEF_IDX(vd->vd_ndx);
4802 assert(vernum <= maxvernum);
4803 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4804 obj->vertab[vernum].hash = vd->vd_hash;
4805 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4806 obj->vertab[vernum].file = NULL;
4807 obj->vertab[vernum].flags = 0;
4809 if (vd->vd_next == 0)
4811 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4815 while (vn != NULL) {
4816 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4819 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4821 if (check_object_provided_version(obj, depobj, vna))
4823 vernum = VER_NEED_IDX(vna->vna_other);
4824 assert(vernum <= maxvernum);
4825 obj->vertab[vernum].hash = vna->vna_hash;
4826 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4827 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4828 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4829 VER_INFO_HIDDEN : 0;
4830 if (vna->vna_next == 0)
4832 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4834 if (vn->vn_next == 0)
4836 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4842 rtld_verify_versions(const Objlist *objlist)
4844 Objlist_Entry *entry;
4848 STAILQ_FOREACH(entry, objlist, link) {
4850 * Skip dummy objects or objects that have their version requirements
4853 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4855 if (rtld_verify_object_versions(entry->obj) == -1) {
4857 if (ld_tracing == NULL)
4861 if (rc == 0 || ld_tracing != NULL)
4862 rc = rtld_verify_object_versions(&obj_rtld);
4867 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4872 vernum = VER_NDX(obj->versyms[symnum]);
4873 if (vernum >= obj->vernum) {
4874 _rtld_error("%s: symbol %s has wrong verneed value %d",
4875 obj->path, obj->strtab + symnum, vernum);
4876 } else if (obj->vertab[vernum].hash != 0) {
4877 return &obj->vertab[vernum];
4884 _rtld_get_stack_prot(void)
4887 return (stack_prot);
4891 _rtld_is_dlopened(void *arg)
4894 RtldLockState lockstate;
4897 rlock_acquire(rtld_bind_lock, &lockstate);
4900 obj = obj_from_addr(arg);
4902 _rtld_error("No shared object contains address");
4903 lock_release(rtld_bind_lock, &lockstate);
4906 res = obj->dlopened ? 1 : 0;
4907 lock_release(rtld_bind_lock, &lockstate);
4912 map_stacks_exec(RtldLockState *lockstate)
4914 void (*thr_map_stacks_exec)(void);
4916 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4918 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4919 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4920 if (thr_map_stacks_exec != NULL) {
4921 stack_prot |= PROT_EXEC;
4922 thr_map_stacks_exec();
4927 symlook_init(SymLook *dst, const char *name)
4930 bzero(dst, sizeof(*dst));
4932 dst->hash = elf_hash(name);
4933 dst->hash_gnu = gnu_hash(name);
4937 symlook_init_from_req(SymLook *dst, const SymLook *src)
4940 dst->name = src->name;
4941 dst->hash = src->hash;
4942 dst->hash_gnu = src->hash_gnu;
4943 dst->ventry = src->ventry;
4944 dst->flags = src->flags;
4945 dst->defobj_out = NULL;
4946 dst->sym_out = NULL;
4947 dst->lockstate = src->lockstate;
4952 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
4955 parse_libdir(const char *str)
4957 static const int RADIX = 10; /* XXXJA: possibly support hex? */
4964 for (c = *str; c != '\0'; c = *++str) {
4965 if (c < '0' || c > '9')
4972 /* Make sure we actually parsed something. */
4974 _rtld_error("failed to parse directory FD from '%s'", str);
4981 * Overrides for libc_pic-provided functions.
4985 __getosreldate(void)
4995 oid[1] = KERN_OSRELDATE;
4997 len = sizeof(osrel);
4998 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4999 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5011 void (*__cleanup)(void);
5012 int __isthreaded = 0;
5013 int _thread_autoinit_dummy_decl = 1;
5016 * No unresolved symbols for rtld.
5019 __pthread_cxa_finalize(struct dl_phdr_info *a)
5024 __stack_chk_fail(void)
5027 _rtld_error("stack overflow detected; terminated");
5030 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
5036 _rtld_error("buffer overflow detected; terminated");
5041 rtld_strerror(int errnum)
5044 if (errnum < 0 || errnum >= sys_nerr)
5045 return ("Unknown error");
5046 return (sys_errlist[errnum]);