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>
49 #include <sys/resident.h>
52 #include <machine/tls.h>
67 #include "rtld_printf.h"
70 #define PATH_RTLD "/usr/libexec/ld-elf.so.2"
71 #define LD_ARY_CACHE 16
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 *_getenv_ld(const char *id);
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 void distribute_static_tls(Objlist *, RtldLockState *);
89 static Obj_Entry *dlcheck(void *);
90 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
91 int lo_flags, int mode, RtldLockState *lockstate);
92 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
93 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
94 static bool donelist_check(DoneList *, const Obj_Entry *);
95 static void errmsg_restore(char *);
96 static char *errmsg_save(void);
97 static void *fill_search_info(const char *, size_t, void *);
98 static char *find_library(const char *, const Obj_Entry *, int *);
99 static const char *gethints(bool);
100 static void init_dag(Obj_Entry *);
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 uint_fast32_t gnu_hash (const char *);
163 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
164 const unsigned long);
166 void r_debug_state(struct r_debug *, struct link_map *) __noinline;
167 void _r_debug_postinit(struct link_map *) __noinline;
172 static char *error_message; /* Message for dlerror(), or NULL */
173 struct r_debug r_debug; /* for GDB; */
174 static bool libmap_disable; /* Disable libmap */
175 static bool ld_loadfltr; /* Immediate filters processing */
176 static char *libmap_override; /* Maps to use in addition to libmap.conf */
177 static bool trust; /* False for setuid and setgid programs */
178 static bool dangerous_ld_env; /* True if environment variables have been
179 used to affect the libraries loaded */
180 static const char *ld_bind_now; /* Environment variable for immediate binding */
181 static const char *ld_debug; /* Environment variable for debugging */
182 static const char *ld_library_path; /* Environment variable for search path */
183 static const char *ld_library_dirs; /* Env variable for library descriptors */
184 static char *ld_preload; /* Environment variable for libraries to
186 static const char *ld_elf_hints_path; /* Env var. for alternative hints path */
187 static const char *ld_tracing; /* Called from ldd to print libs */
188 static const char *ld_utrace; /* Use utrace() to log events. */
189 static int (*rtld_functrace)( /* Optional function call tracing hook */
190 const char *caller_obj,
191 const char *callee_obj,
192 const char *callee_func,
194 static const Obj_Entry *rtld_functrace_obj; /* Object thereof */
195 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
196 static Obj_Entry **obj_tail; /* Link field of last object in list */
197 static Obj_Entry **preload_tail;
198 static Obj_Entry *obj_main; /* The main program shared object */
199 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
200 static unsigned int obj_count; /* Number of objects in obj_list */
201 static unsigned int obj_loads; /* Number of objects in obj_list */
203 static int ld_resident; /* Non-zero if resident */
204 static const char *ld_ary[LD_ARY_CACHE];
206 static Objlist initlist;
208 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
209 STAILQ_HEAD_INITIALIZER(list_global);
210 static Objlist list_main = /* Objects loaded at program startup */
211 STAILQ_HEAD_INITIALIZER(list_main);
212 static Objlist list_fini = /* Objects needing fini() calls */
213 STAILQ_HEAD_INITIALIZER(list_fini);
215 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */
216 const char *__ld_sharedlib_base;
218 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
220 extern Elf_Dyn _DYNAMIC;
221 #pragma weak _DYNAMIC
222 #ifndef RTLD_IS_DYNAMIC
223 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
226 #ifdef ENABLE_OSRELDATE
230 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
232 static int max_stack_flags;
236 * Global declarations normally provided by crt1. The dynamic linker is
237 * not built with crt1, so we have to provide them ourselves.
243 * Used to pass argc, argv to init functions.
249 * Globals to control TLS allocation.
251 size_t tls_last_offset; /* Static TLS offset of last module */
252 size_t tls_last_size; /* Static TLS size of last module */
253 size_t tls_static_space; /* Static TLS space allocated */
254 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
255 int tls_max_index = 1; /* Largest module index allocated */
258 * Fill in a DoneList with an allocation large enough to hold all of
259 * the currently-loaded objects. Keep this as a macro since it calls
260 * alloca and we want that to occur within the scope of the caller.
262 #define donelist_init(dlp) \
263 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
264 assert((dlp)->objs != NULL), \
265 (dlp)->num_alloc = obj_count, \
268 #define UTRACE_DLOPEN_START 1
269 #define UTRACE_DLOPEN_STOP 2
270 #define UTRACE_DLCLOSE_START 3
271 #define UTRACE_DLCLOSE_STOP 4
272 #define UTRACE_LOAD_OBJECT 5
273 #define UTRACE_UNLOAD_OBJECT 6
274 #define UTRACE_ADD_RUNDEP 7
275 #define UTRACE_PRELOAD_FINISHED 8
276 #define UTRACE_INIT_CALL 9
277 #define UTRACE_FINI_CALL 10
280 char sig[4]; /* 'RTLD' */
283 void *mapbase; /* Used for 'parent' and 'init/fini' */
285 int refcnt; /* Used for 'mode' */
286 char name[MAXPATHLEN];
289 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
290 if (ld_utrace != NULL) \
291 ld_utrace_log(e, h, mb, ms, r, n); \
295 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
296 int refcnt, const char *name)
298 struct utrace_rtld ut;
306 ut.mapbase = mapbase;
307 ut.mapsize = mapsize;
309 bzero(ut.name, sizeof(ut.name));
311 strlcpy(ut.name, name, sizeof(ut.name));
312 utrace(&ut, sizeof(ut));
316 * Main entry point for dynamic linking. The first argument is the
317 * stack pointer. The stack is expected to be laid out as described
318 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
319 * Specifically, the stack pointer points to a word containing
320 * ARGC. Following that in the stack is a null-terminated sequence
321 * of pointers to argument strings. Then comes a null-terminated
322 * sequence of pointers to environment strings. Finally, there is a
323 * sequence of "auxiliary vector" entries.
325 * The second argument points to a place to store the dynamic linker's
326 * exit procedure pointer and the third to a place to store the main
329 * The return value is the main program's entry point.
332 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
334 Elf_Auxinfo *aux_info[AT_COUNT];
342 Objlist_Entry *entry;
344 Obj_Entry *last_interposer;
346 /* marino: DO NOT MOVE THESE VARIABLES TO _rtld
347 Obj_Entry **preload_tail;
349 from global to here. It will break the DWARF2 unwind scheme.
353 * On entry, the dynamic linker itself has not been relocated yet.
354 * Be very careful not to reference any global data until after
355 * init_rtld has returned. It is OK to reference file-scope statics
356 * and string constants, and to call static and global functions.
359 /* Find the auxiliary vector on the stack. */
362 sp += argc + 1; /* Skip over arguments and NULL terminator */
366 * If we aren't already resident we have to dig out some more info.
367 * Note that auxinfo does not exist when we are resident.
369 * I'm not sure about the ld_resident check. It seems to read zero
370 * prior to relocation, which is what we want. When running from a
371 * resident copy everything will be relocated so we are definitely
374 if (ld_resident == 0) {
375 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
377 aux = (Elf_Auxinfo *) sp;
379 /* Digest the auxiliary vector. */
380 for (i = 0; i < AT_COUNT; i++)
382 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
383 if (auxp->a_type < AT_COUNT)
384 aux_info[auxp->a_type] = auxp;
387 /* Initialize and relocate ourselves. */
388 assert(aux_info[AT_BASE] != NULL);
389 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
392 ld_index = 0; /* don't use old env cache in case we are resident */
393 __progname = obj_rtld.path;
394 argv0 = argv[0] != NULL ? argv[0] : "(null)";
399 trust = !issetugid();
401 ld_bind_now = _getenv_ld("LD_BIND_NOW");
403 * If the process is tainted, then we un-set the dangerous environment
404 * variables. The process will be marked as tainted until setuid(2)
405 * is called. If any child process calls setuid(2) we do not want any
406 * future processes to honor the potentially un-safe variables.
409 if ( unsetenv("LD_DEBUG")
410 || unsetenv("LD_PRELOAD")
411 || unsetenv("LD_LIBRARY_PATH")
412 || unsetenv("LD_LIBRARY_PATH_FDS")
413 || unsetenv("LD_ELF_HINTS_PATH")
414 || unsetenv("LD_LIBMAP")
415 || unsetenv("LD_LIBMAP_DISABLE")
416 || unsetenv("LD_LOADFLTR")
417 || unsetenv("LD_SHAREDLIB_BASE")
419 _rtld_error("environment corrupt; aborting");
423 __ld_sharedlib_base = _getenv_ld("LD_SHAREDLIB_BASE");
424 ld_debug = _getenv_ld("LD_DEBUG");
425 libmap_disable = _getenv_ld("LD_LIBMAP_DISABLE") != NULL;
426 libmap_override = (char *)_getenv_ld("LD_LIBMAP");
427 ld_library_path = _getenv_ld("LD_LIBRARY_PATH");
428 ld_library_dirs = _getenv_ld("LD_LIBRARY_PATH_FDS");
429 ld_preload = (char *)_getenv_ld("LD_PRELOAD");
430 ld_elf_hints_path = _getenv_ld("LD_ELF_HINTS_PATH");
431 ld_loadfltr = _getenv_ld("LD_LOADFLTR") != NULL;
432 dangerous_ld_env = (ld_library_path != NULL)
433 || (ld_preload != NULL)
434 || (ld_elf_hints_path != NULL)
436 || (libmap_override != NULL)
439 ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS");
440 ld_utrace = _getenv_ld("LD_UTRACE");
442 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
443 ld_elf_hints_path = _PATH_ELF_HINTS;
445 if (ld_debug != NULL && *ld_debug != '\0')
447 dbg("%s is initialized, base address = %p", __progname,
448 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
449 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
450 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
452 dbg("initializing thread locks");
456 * If we are resident we can skip work that we have already done.
457 * Note that the stack is reset and there is no Elf_Auxinfo
458 * when running from a resident image, and the static globals setup
459 * between here and resident_skip will have already been setup.
465 * Load the main program, or process its program header if it is
468 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
469 int fd = aux_info[AT_EXECFD]->a_un.a_val;
470 dbg("loading main program");
471 obj_main = map_object(fd, argv0, NULL);
473 if (obj_main == NULL)
476 max_stack_flags = obj_main->stack_flags;
478 } else { /* Main program already loaded. */
479 const Elf_Phdr *phdr;
483 dbg("processing main program's program header");
484 assert(aux_info[AT_PHDR] != NULL);
485 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
486 assert(aux_info[AT_PHNUM] != NULL);
487 phnum = aux_info[AT_PHNUM]->a_un.a_val;
488 assert(aux_info[AT_PHENT] != NULL);
489 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
490 assert(aux_info[AT_ENTRY] != NULL);
491 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
492 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
496 char buf[MAXPATHLEN];
497 if (aux_info[AT_EXECPATH] != NULL) {
500 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
501 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
502 if (kexecpath[0] == '/')
503 obj_main->path = kexecpath;
504 else if (getcwd(buf, sizeof(buf)) == NULL ||
505 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
506 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
507 obj_main->path = xstrdup(argv0);
509 obj_main->path = xstrdup(buf);
511 char resolved[MAXPATHLEN];
512 dbg("No AT_EXECPATH");
513 if (argv0[0] == '/') {
514 if (realpath(argv0, resolved) != NULL)
515 obj_main->path = xstrdup(resolved);
517 obj_main->path = xstrdup(argv0);
519 if (getcwd(buf, sizeof(buf)) != NULL
520 && strlcat(buf, "/", sizeof(buf)) < sizeof(buf)
521 && strlcat(buf, argv0, sizeof (buf)) < sizeof(buf)
522 && access(buf, R_OK) == 0
523 && realpath(buf, resolved) != NULL)
524 obj_main->path = xstrdup(resolved);
526 obj_main->path = xstrdup(argv0);
529 dbg("obj_main path %s", obj_main->path);
530 obj_main->mainprog = true;
532 if (aux_info[AT_STACKPROT] != NULL &&
533 aux_info[AT_STACKPROT]->a_un.a_val != 0)
534 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
537 * Get the actual dynamic linker pathname from the executable if
538 * possible. (It should always be possible.) That ensures that
539 * gdb will find the right dynamic linker even if a non-standard
542 if (obj_main->interp != NULL &&
543 strcmp(obj_main->interp, obj_rtld.path) != 0) {
545 obj_rtld.path = xstrdup(obj_main->interp);
546 __progname = obj_rtld.path;
549 digest_dynamic(obj_main, 0);
550 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
551 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
552 obj_main->dynsymcount);
554 linkmap_add(obj_main);
555 linkmap_add(&obj_rtld);
557 /* Link the main program into the list of objects. */
558 *obj_tail = obj_main;
559 obj_tail = &obj_main->next;
563 /* Initialize a fake symbol for resolving undefined weak references. */
564 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
565 sym_zero.st_shndx = SHN_UNDEF;
566 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
569 libmap_disable = (bool)lm_init(libmap_override);
571 dbg("loading LD_PRELOAD libraries");
572 if (load_preload_objects() == -1)
574 preload_tail = obj_tail;
576 dbg("loading needed objects");
577 if (load_needed_objects(obj_main, 0) == -1)
580 /* Make a list of all objects loaded at startup. */
581 last_interposer = obj_main;
582 for (obj = obj_list; obj != NULL; obj = obj->next) {
583 if (obj->z_interpose && obj != obj_main) {
584 objlist_put_after(&list_main, last_interposer, obj);
585 last_interposer = obj;
587 objlist_push_tail(&list_main, obj);
592 dbg("checking for required versions");
593 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
598 if (ld_tracing) { /* We're done */
599 trace_loaded_objects(obj_main);
603 if (ld_resident) /* XXX clean this up! */
606 if (_getenv_ld("LD_DUMP_REL_PRE") != NULL) {
607 dump_relocations(obj_main);
611 /* setup TLS for main thread */
612 dbg("initializing initial thread local storage");
613 STAILQ_FOREACH(entry, &list_main, link) {
615 * Allocate all the initial objects out of the static TLS
616 * block even if they didn't ask for it.
618 allocate_tls_offset(entry->obj);
621 tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA;
624 * Do not try to allocate the TLS here, let libc do it itself.
625 * (crt1 for the program will call _init_tls())
628 if (relocate_objects(obj_main,
629 ld_bind_now != NULL && *ld_bind_now != '\0',
630 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
633 dbg("doing copy relocations");
634 if (do_copy_relocations(obj_main) == -1)
639 if (_getenv_ld("LD_RESIDENT_UNREGISTER_NOW")) {
640 if (exec_sys_unregister(-1) < 0) {
641 dbg("exec_sys_unregister failed %d\n", errno);
644 dbg("exec_sys_unregister success\n");
648 if (_getenv_ld("LD_DUMP_REL_POST") != NULL) {
649 dump_relocations(obj_main);
653 dbg("initializing key program variables");
654 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
655 set_program_var("environ", env);
656 set_program_var("__elf_aux_vector", aux);
658 if (_getenv_ld("LD_RESIDENT_REGISTER_NOW")) {
659 extern void resident_start(void);
661 if (exec_sys_register(resident_start) < 0) {
662 dbg("exec_sys_register failed %d\n", errno);
665 dbg("exec_sys_register success\n");
669 /* Make a list of init functions to call. */
670 objlist_init(&initlist);
671 initlist_add_objects(obj_list, preload_tail, &initlist);
673 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
675 map_stacks_exec(NULL);
677 dbg("resolving ifuncs");
679 RtldLockState lockstate;
681 wlock_acquire(rtld_bind_lock, &lockstate);
682 if (resolve_objects_ifunc(
684 (ld_bind_now != NULL && *ld_bind_now != '\0'),
689 lock_release(rtld_bind_lock, &lockstate);
693 * Do NOT call the initlist here, give libc a chance to set up
694 * the initial TLS segment. crt1 will then call _rtld_call_init().
697 dbg("transferring control to program entry point = %p", obj_main->entry);
699 /* Return the exit procedure and the program entry point. */
700 *exit_proc = rtld_exit;
702 return (func_ptr_type) obj_main->entry;
706 * Call the initialization list for dynamically loaded libraries.
707 * (called from crt1.c).
710 _rtld_call_init(void)
712 RtldLockState lockstate;
715 if (!obj_main->note_present && obj_main->valid_hash_gnu) {
717 * The use of a linker script with a PHDRS directive that does not include
718 * PT_NOTE will block the crt_no_init note. In this case we'll look for the
719 * recently added GNU hash dynamic tag which gets built by default. It is
720 * extremely unlikely to find a pre-3.1 binary without a PT_NOTE header and
721 * a gnu hash tag. If gnu hash found, consider binary to use new crt code.
723 obj_main->crt_no_init = true;
724 dbg("Setting crt_no_init without presence of PT_NOTE header");
727 wlock_acquire(rtld_bind_lock, &lockstate);
728 if (obj_main->crt_no_init)
732 * Make sure we don't call the main program's init and fini functions
733 * for binaries linked with old crt1 which calls _init itself.
735 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
736 obj_main->init_array = obj_main->fini_array = (Elf_Addr)NULL;
738 objlist_call_init(&initlist, &lockstate);
739 _r_debug_postinit(&obj_main->linkmap);
740 objlist_clear(&initlist);
741 dbg("loading filtees");
742 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
743 if (ld_loadfltr || obj->z_loadfltr)
744 load_filtees(obj, 0, &lockstate);
746 lock_release(rtld_bind_lock, &lockstate);
750 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
755 ptr = (void *)make_function_pointer(def, obj);
756 target = ((Elf_Addr (*)(void))ptr)();
757 return ((void *)target);
761 _rtld_bind(Obj_Entry *obj, Elf_Size reloff, void *stack)
765 const Obj_Entry *defobj;
768 RtldLockState lockstate;
770 rlock_acquire(rtld_bind_lock, &lockstate);
771 if (sigsetjmp(lockstate.env, 0) != 0)
772 lock_upgrade(rtld_bind_lock, &lockstate);
774 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
776 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
778 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
779 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
783 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
784 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
786 target = (Elf_Addr)(defobj->relocbase + def->st_value);
788 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
789 defobj->strtab + def->st_name, basename(obj->path),
790 (void *)target, basename(defobj->path));
793 * If we have a function call tracing hook, and the
794 * hook would like to keep tracing this one function,
795 * prevent the relocation so we will wind up here
796 * the next time again.
798 * We don't want to functrace calls from the functracer
799 * to avoid recursive loops.
801 if (rtld_functrace != NULL && obj != rtld_functrace_obj) {
802 if (rtld_functrace(obj->path,
804 defobj->strtab + def->st_name,
806 lock_release(rtld_bind_lock, &lockstate);
812 * Write the new contents for the jmpslot. Note that depending on
813 * architecture, the value which we need to return back to the
814 * lazy binding trampoline may or may not be the target
815 * address. The value returned from reloc_jmpslot() is the value
816 * that the trampoline needs.
818 target = reloc_jmpslot(where, target, defobj, obj, rel);
819 lock_release(rtld_bind_lock, &lockstate);
824 * Error reporting function. Use it like printf. If formats the message
825 * into a buffer, and sets things up so that the next call to dlerror()
826 * will return the message.
829 _rtld_error(const char *fmt, ...)
831 static char buf[512];
835 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
841 * Return a dynamically-allocated copy of the current error message, if any.
846 return error_message == NULL ? NULL : xstrdup(error_message);
850 * Restore the current error message from a copy which was previously saved
851 * by errmsg_save(). The copy is freed.
854 errmsg_restore(char *saved_msg)
856 if (saved_msg == NULL)
857 error_message = NULL;
859 _rtld_error("%s", saved_msg);
865 basename(const char *name)
867 const char *p = strrchr(name, '/');
868 return p != NULL ? p + 1 : name;
871 static struct utsname uts;
874 origin_subst_one(char *real, const char *kw, const char *subst,
877 char *p, *p1, *res, *resp;
878 int subst_len, kw_len, subst_count, old_len, new_len;
883 * First, count the number of the keyword occurrences, to
884 * preallocate the final string.
886 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
893 * If the keyword is not found, just return.
895 if (subst_count == 0)
896 return (may_free ? real : xstrdup(real));
899 * There is indeed something to substitute. Calculate the
900 * length of the resulting string, and allocate it.
902 subst_len = strlen(subst);
903 old_len = strlen(real);
904 new_len = old_len + (subst_len - kw_len) * subst_count;
905 res = xmalloc(new_len + 1);
908 * Now, execute the substitution loop.
910 for (p = real, resp = res, *resp = '\0';;) {
913 /* Copy the prefix before keyword. */
914 memcpy(resp, p, p1 - p);
916 /* Keyword replacement. */
917 memcpy(resp, subst, subst_len);
925 /* Copy to the end of string and finish. */
933 origin_subst(char *real, const char *origin_path)
935 char *res1, *res2, *res3, *res4;
937 if (uts.sysname[0] == '\0') {
938 if (uname(&uts) != 0) {
939 _rtld_error("utsname failed: %d", errno);
943 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false);
944 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true);
945 res3 = origin_subst_one(res2, "$OSREL", uts.release, true);
946 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true);
953 const char *msg = dlerror();
957 rtld_fdputstr(STDERR_FILENO, msg);
958 rtld_fdputchar(STDERR_FILENO, '\n');
963 * Process a shared object's DYNAMIC section, and save the important
964 * information in its Obj_Entry structure.
967 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
968 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
971 Needed_Entry **needed_tail = &obj->needed;
972 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
973 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
974 const Elf_Hashelt *hashtab;
975 const Elf32_Word *hashval;
976 Elf32_Word bkt, nmaskwords;
979 int plttype = DT_REL;
985 obj->bind_now = false;
986 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
987 switch (dynp->d_tag) {
990 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
994 obj->relsize = dynp->d_un.d_val;
998 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1002 obj->pltrel = (const Elf_Rel *)
1003 (obj->relocbase + dynp->d_un.d_ptr);
1007 obj->pltrelsize = dynp->d_un.d_val;
1011 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
1015 obj->relasize = dynp->d_un.d_val;
1019 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1023 plttype = dynp->d_un.d_val;
1024 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1028 obj->symtab = (const Elf_Sym *)
1029 (obj->relocbase + dynp->d_un.d_ptr);
1033 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1037 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
1041 obj->strsize = dynp->d_un.d_val;
1045 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
1050 obj->verneednum = dynp->d_un.d_val;
1054 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
1059 obj->verdefnum = dynp->d_un.d_val;
1063 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1069 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1071 obj->nbuckets = hashtab[0];
1072 obj->nchains = hashtab[1];
1073 obj->buckets = hashtab + 2;
1074 obj->chains = obj->buckets + obj->nbuckets;
1075 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1076 obj->buckets != NULL;
1082 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1084 obj->nbuckets_gnu = hashtab[0];
1085 obj->symndx_gnu = hashtab[1];
1086 nmaskwords = hashtab[2];
1087 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1088 /* Number of bitmask words is required to be power of 2 */
1089 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0);
1090 obj->maskwords_bm_gnu = nmaskwords - 1;
1091 obj->shift2_gnu = hashtab[3];
1092 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
1093 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1094 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1096 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 &&
1097 obj->buckets_gnu != NULL;
1103 Needed_Entry *nep = NEW(Needed_Entry);
1104 nep->name = dynp->d_un.d_val;
1109 needed_tail = &nep->next;
1115 Needed_Entry *nep = NEW(Needed_Entry);
1116 nep->name = dynp->d_un.d_val;
1120 *needed_filtees_tail = nep;
1121 needed_filtees_tail = &nep->next;
1127 Needed_Entry *nep = NEW(Needed_Entry);
1128 nep->name = dynp->d_un.d_val;
1132 *needed_aux_filtees_tail = nep;
1133 needed_aux_filtees_tail = &nep->next;
1138 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1142 obj->textrel = true;
1146 obj->symbolic = true;
1151 * We have to wait until later to process this, because we
1152 * might not have gotten the address of the string table yet.
1162 *dyn_runpath = dynp;
1166 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1169 case DT_PREINIT_ARRAY:
1170 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1173 case DT_PREINIT_ARRAYSZ:
1174 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1178 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1181 case DT_INIT_ARRAYSZ:
1182 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1186 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1190 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1193 case DT_FINI_ARRAYSZ:
1194 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1198 /* XXX - not implemented yet */
1200 dbg("Filling in DT_DEBUG entry");
1201 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1205 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1206 obj->z_origin = true;
1207 if (dynp->d_un.d_val & DF_SYMBOLIC)
1208 obj->symbolic = true;
1209 if (dynp->d_un.d_val & DF_TEXTREL)
1210 obj->textrel = true;
1211 if (dynp->d_un.d_val & DF_BIND_NOW)
1212 obj->bind_now = true;
1213 if (dynp->d_un.d_val & DF_STATIC_TLS)
1214 obj->static_tls = true;
1218 if (dynp->d_un.d_val & DF_1_NOOPEN)
1219 obj->z_noopen = true;
1220 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1221 obj->z_origin = true;
1222 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1224 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1225 obj->bind_now = true;
1226 if (dynp->d_un.d_val & DF_1_NODELETE)
1227 obj->z_nodelete = true;
1228 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1229 obj->z_loadfltr = true;
1230 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1231 obj->z_interpose = true;
1232 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1233 obj->z_nodeflib = true;
1238 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1245 obj->traced = false;
1247 if (plttype == DT_RELA) {
1248 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1250 obj->pltrelasize = obj->pltrelsize;
1251 obj->pltrelsize = 0;
1254 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1255 if (obj->valid_hash_sysv)
1256 obj->dynsymcount = obj->nchains;
1257 else if (obj->valid_hash_gnu) {
1258 obj->dynsymcount = 0;
1259 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1260 if (obj->buckets_gnu[bkt] == 0)
1262 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1265 while ((*hashval++ & 1u) == 0);
1267 obj->dynsymcount += obj->symndx_gnu;
1272 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1273 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1276 if (obj->z_origin && obj->origin_path == NULL) {
1277 obj->origin_path = xmalloc(PATH_MAX);
1278 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1282 if (dyn_runpath != NULL) {
1283 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1285 obj->runpath = origin_subst(obj->runpath, obj->origin_path);
1287 else if (dyn_rpath != NULL) {
1288 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1290 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1293 if (dyn_soname != NULL)
1294 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1298 digest_dynamic(Obj_Entry *obj, int early)
1300 const Elf_Dyn *dyn_rpath;
1301 const Elf_Dyn *dyn_soname;
1302 const Elf_Dyn *dyn_runpath;
1304 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1305 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1309 * Process a shared object's program header. This is used only for the
1310 * main program, when the kernel has already loaded the main program
1311 * into memory before calling the dynamic linker. It creates and
1312 * returns an Obj_Entry structure.
1315 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1318 const Elf_Phdr *phlimit = phdr + phnum;
1320 Elf_Addr note_start, note_end;
1324 for (ph = phdr; ph < phlimit; ph++) {
1325 if (ph->p_type != PT_PHDR)
1329 obj->phsize = ph->p_memsz;
1330 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1334 obj->stack_flags = PF_X | PF_R | PF_W;
1336 for (ph = phdr; ph < phlimit; ph++) {
1337 switch (ph->p_type) {
1340 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1344 if (nsegs == 0) { /* First load segment */
1345 obj->vaddrbase = trunc_page(ph->p_vaddr);
1346 obj->mapbase = obj->vaddrbase + obj->relocbase;
1347 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1349 } else { /* Last load segment */
1350 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1357 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1362 obj->tlssize = ph->p_memsz;
1363 obj->tlsalign = ph->p_align;
1364 obj->tlsinitsize = ph->p_filesz;
1365 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1369 obj->stack_flags = ph->p_flags;
1373 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1374 obj->relro_size = round_page(ph->p_memsz);
1378 obj->note_present = true;
1379 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1380 note_end = note_start + ph->p_filesz;
1381 digest_notes(obj, note_start, note_end);
1386 _rtld_error("%s: too few PT_LOAD segments", path);
1395 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1397 const Elf_Note *note;
1398 const char *note_name;
1401 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1402 note = (const Elf_Note *)((const char *)(note + 1) +
1403 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1404 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1405 if (note->n_namesz != sizeof(NOTE_VENDOR) ||
1406 note->n_descsz != sizeof(int32_t))
1408 if (note->n_type != ABI_NOTETYPE &&
1409 note->n_type != CRT_NOINIT_NOTETYPE)
1411 note_name = (const char *)(note + 1);
1412 if (strncmp(NOTE_VENDOR, note_name, sizeof(NOTE_VENDOR)) != 0)
1414 switch (note->n_type) {
1416 /* DragonFly osrel note */
1417 p = (uintptr_t)(note + 1);
1418 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1419 obj->osrel = *(const int32_t *)(p);
1420 dbg("note osrel %d", obj->osrel);
1422 case CRT_NOINIT_NOTETYPE:
1423 /* DragonFly 'crt does not call init' note */
1424 obj->crt_no_init = true;
1425 dbg("note crt_no_init");
1432 dlcheck(void *handle)
1436 for (obj = obj_list; obj != NULL; obj = obj->next)
1437 if (obj == (Obj_Entry *) handle)
1440 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1441 _rtld_error("Invalid shared object handle %p", handle);
1448 * If the given object is already in the donelist, return true. Otherwise
1449 * add the object to the list and return false.
1452 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1456 for (i = 0; i < dlp->num_used; i++)
1457 if (dlp->objs[i] == obj)
1460 * Our donelist allocation should always be sufficient. But if
1461 * our threads locking isn't working properly, more shared objects
1462 * could have been loaded since we allocated the list. That should
1463 * never happen, but we'll handle it properly just in case it does.
1465 if (dlp->num_used < dlp->num_alloc)
1466 dlp->objs[dlp->num_used++] = obj;
1471 * Hash function for symbol table lookup. Don't even think about changing
1472 * this. It is specified by the System V ABI.
1475 elf_hash(const char *name)
1477 const unsigned char *p = (const unsigned char *) name;
1478 unsigned long h = 0;
1481 while (*p != '\0') {
1482 h = (h << 4) + *p++;
1483 if ((g = h & 0xf0000000) != 0)
1491 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1492 * unsigned in case it's implemented with a wider type.
1494 static uint_fast32_t
1495 gnu_hash(const char *s)
1501 for (c = *s; c != '\0'; c = *++s)
1503 return (h & 0xffffffff);
1508 * Find the library with the given name, and return its full pathname.
1509 * The returned string is dynamically allocated. Generates an error
1510 * message and returns NULL if the library cannot be found.
1512 * If the second argument is non-NULL, then it refers to an already-
1513 * loaded shared object, whose library search path will be searched.
1515 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1516 * descriptor (which is close-on-exec) will be passed out via the third
1519 * The search order is:
1520 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1521 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1523 * DT_RUNPATH in the referencing file
1524 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1526 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1528 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1531 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1535 bool nodeflib, objgiven;
1537 objgiven = refobj != NULL;
1538 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1539 if (xname[0] != '/' && !trust) {
1540 _rtld_error("Absolute pathname required for shared object \"%s\"",
1544 if (objgiven && refobj->z_origin) {
1545 return (origin_subst(__DECONST(char *, xname),
1546 refobj->origin_path));
1548 return (xstrdup(xname));
1552 if (libmap_disable || !objgiven ||
1553 (name = lm_find(refobj->path, xname)) == NULL)
1554 name = (char *)xname;
1556 dbg(" Searching for \"%s\"", name);
1558 nodeflib = objgiven ? refobj->z_nodeflib : false;
1560 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1561 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1562 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1563 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1565 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1566 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL ||
1567 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1568 (objgiven && !nodeflib &&
1569 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1572 if (objgiven && refobj->path != NULL) {
1573 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1574 name, basename(refobj->path));
1576 _rtld_error("Shared object \"%s\" not found", name);
1582 * Given a symbol number in a referencing object, find the corresponding
1583 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1584 * no definition was found. Returns a pointer to the Obj_Entry of the
1585 * defining object via the reference parameter DEFOBJ_OUT.
1588 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1589 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1590 RtldLockState *lockstate)
1594 const Obj_Entry *defobj;
1600 * If we have already found this symbol, get the information from
1603 if (symnum >= refobj->dynsymcount)
1604 return NULL; /* Bad object */
1605 if (cache != NULL && cache[symnum].sym != NULL) {
1606 *defobj_out = cache[symnum].obj;
1607 return cache[symnum].sym;
1610 ref = refobj->symtab + symnum;
1611 name = refobj->strtab + ref->st_name;
1616 * We don't have to do a full scale lookup if the symbol is local.
1617 * We know it will bind to the instance in this load module; to
1618 * which we already have a pointer (ie ref). By not doing a lookup,
1619 * we not only improve performance, but it also avoids unresolvable
1620 * symbols when local symbols are not in the hash table.
1622 * This might occur for TLS module relocations, which simply use
1625 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1626 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1627 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1630 symlook_init(&req, name);
1632 req.ventry = fetch_ventry(refobj, symnum);
1633 req.lockstate = lockstate;
1634 res = symlook_default(&req, refobj);
1637 defobj = req.defobj_out;
1645 * If we found no definition and the reference is weak, treat the
1646 * symbol as having the value zero.
1648 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1654 *defobj_out = defobj;
1655 /* Record the information in the cache to avoid subsequent lookups. */
1656 if (cache != NULL) {
1657 cache[symnum].sym = def;
1658 cache[symnum].obj = defobj;
1661 if (refobj != &obj_rtld)
1662 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1668 * Return the search path from the ldconfig hints file, reading it if
1669 * necessary. If nostdlib is true, then the default search paths are
1670 * not added to result.
1672 * Returns NULL if there are problems with the hints file,
1673 * or if the search path there is empty.
1676 gethints(bool nostdlib)
1678 static char *hints, *filtered_path;
1679 struct elfhints_hdr hdr;
1680 struct fill_search_info_args sargs, hargs;
1681 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1682 struct dl_serpath *SLPpath, *hintpath;
1684 unsigned int SLPndx, hintndx, fndx, fcount;
1689 /* First call, read the hints file */
1690 if (hints == NULL) {
1691 /* Keep from trying again in case the hints file is bad. */
1694 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1696 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1697 hdr.magic != ELFHINTS_MAGIC ||
1702 p = xmalloc(hdr.dirlistlen + 1);
1703 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1704 read(fd, p, hdr.dirlistlen + 1) !=
1705 (ssize_t)hdr.dirlistlen + 1) {
1715 * If caller agreed to receive list which includes the default
1716 * paths, we are done. Otherwise, if we still have not
1717 * calculated filtered result, do it now.
1720 return (hints[0] != '\0' ? hints : NULL);
1721 if (filtered_path != NULL)
1725 * Obtain the list of all configured search paths, and the
1726 * list of the default paths.
1728 * First estimate the size of the results.
1730 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1732 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1735 sargs.request = RTLD_DI_SERINFOSIZE;
1736 sargs.serinfo = &smeta;
1737 hargs.request = RTLD_DI_SERINFOSIZE;
1738 hargs.serinfo = &hmeta;
1740 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1741 path_enumerate(p, fill_search_info, &hargs);
1743 SLPinfo = xmalloc(smeta.dls_size);
1744 hintinfo = xmalloc(hmeta.dls_size);
1747 * Next fetch both sets of paths.
1749 sargs.request = RTLD_DI_SERINFO;
1750 sargs.serinfo = SLPinfo;
1751 sargs.serpath = &SLPinfo->dls_serpath[0];
1752 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1754 hargs.request = RTLD_DI_SERINFO;
1755 hargs.serinfo = hintinfo;
1756 hargs.serpath = &hintinfo->dls_serpath[0];
1757 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1759 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1760 path_enumerate(p, fill_search_info, &hargs);
1763 * Now calculate the difference between two sets, by excluding
1764 * standard paths from the full set.
1768 filtered_path = xmalloc(hdr.dirlistlen + 1);
1769 hintpath = &hintinfo->dls_serpath[0];
1770 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1772 SLPpath = &SLPinfo->dls_serpath[0];
1774 * Check each standard path against current.
1776 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1777 /* matched, skip the path */
1778 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1786 * Not matched against any standard path, add the path
1787 * to result. Separate consecutive paths with ':'.
1790 filtered_path[fndx] = ':';
1794 flen = strlen(hintpath->dls_name);
1795 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1798 filtered_path[fndx] = '\0';
1804 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1808 init_dag(Obj_Entry *root)
1810 const Needed_Entry *needed;
1811 const Objlist_Entry *elm;
1814 if (root->dag_inited)
1816 donelist_init(&donelist);
1818 /* Root object belongs to own DAG. */
1819 objlist_push_tail(&root->dldags, root);
1820 objlist_push_tail(&root->dagmembers, root);
1821 donelist_check(&donelist, root);
1824 * Add dependencies of root object to DAG in breadth order
1825 * by exploiting the fact that each new object get added
1826 * to the tail of the dagmembers list.
1828 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1829 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1830 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1832 objlist_push_tail(&needed->obj->dldags, root);
1833 objlist_push_tail(&root->dagmembers, needed->obj);
1836 root->dag_inited = true;
1840 process_nodelete(Obj_Entry *root)
1842 const Objlist_Entry *elm;
1845 * Walk over object DAG and process every dependent object that
1846 * is marked as DF_1_NODELETE. They need to grow their own DAG,
1847 * which then should have its reference upped separately.
1849 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1850 if (elm->obj != NULL && elm->obj->z_nodelete &&
1851 !elm->obj->ref_nodel) {
1852 dbg("obj %s nodelete", elm->obj->path);
1855 elm->obj->ref_nodel = true;
1861 * Initialize the dynamic linker. The argument is the address at which
1862 * the dynamic linker has been mapped into memory. The primary task of
1863 * this function is to relocate the dynamic linker.
1866 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1868 Obj_Entry objtmp; /* Temporary rtld object */
1869 const Elf_Ehdr *ehdr;
1870 const Elf_Dyn *dyn_rpath;
1871 const Elf_Dyn *dyn_soname;
1872 const Elf_Dyn *dyn_runpath;
1875 * Conjure up an Obj_Entry structure for the dynamic linker.
1877 * The "path" member can't be initialized yet because string constants
1878 * cannot yet be accessed. Below we will set it correctly.
1880 memset(&objtmp, 0, sizeof(objtmp));
1883 objtmp.mapbase = mapbase;
1885 objtmp.relocbase = mapbase;
1887 if (RTLD_IS_DYNAMIC()) {
1888 objtmp.dynamic = rtld_dynamic(&objtmp);
1889 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1890 assert(objtmp.needed == NULL);
1891 assert(!objtmp.textrel);
1894 * Temporarily put the dynamic linker entry into the object list, so
1895 * that symbols can be found.
1898 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1900 ehdr = (Elf_Ehdr *)mapbase;
1901 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
1902 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]);
1904 /* Initialize the object list. */
1905 obj_tail = &obj_list;
1907 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1908 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1910 #ifdef ENABLE_OSRELDATE
1911 if (aux_info[AT_OSRELDATE] != NULL)
1912 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1915 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1917 /* Replace the path with a dynamically allocated copy. */
1918 obj_rtld.path = xstrdup(PATH_RTLD);
1920 r_debug.r_brk = r_debug_state;
1921 r_debug.r_state = RT_CONSISTENT;
1925 * Add the init functions from a needed object list (and its recursive
1926 * needed objects) to "list". This is not used directly; it is a helper
1927 * function for initlist_add_objects(). The write lock must be held
1928 * when this function is called.
1931 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1933 /* Recursively process the successor needed objects. */
1934 if (needed->next != NULL)
1935 initlist_add_neededs(needed->next, list);
1937 /* Process the current needed object. */
1938 if (needed->obj != NULL)
1939 initlist_add_objects(needed->obj, &needed->obj->next, list);
1943 * Scan all of the DAGs rooted in the range of objects from "obj" to
1944 * "tail" and add their init functions to "list". This recurses over
1945 * the DAGs and ensure the proper init ordering such that each object's
1946 * needed libraries are initialized before the object itself. At the
1947 * same time, this function adds the objects to the global finalization
1948 * list "list_fini" in the opposite order. The write lock must be
1949 * held when this function is called.
1952 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1955 if (obj->init_scanned || obj->init_done)
1957 obj->init_scanned = true;
1959 /* Recursively process the successor objects. */
1960 if (&obj->next != tail)
1961 initlist_add_objects(obj->next, tail, list);
1963 /* Recursively process the needed objects. */
1964 if (obj->needed != NULL)
1965 initlist_add_neededs(obj->needed, list);
1966 if (obj->needed_filtees != NULL)
1967 initlist_add_neededs(obj->needed_filtees, list);
1968 if (obj->needed_aux_filtees != NULL)
1969 initlist_add_neededs(obj->needed_aux_filtees, list);
1971 /* Add the object to the init list. */
1972 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1973 obj->init_array != (Elf_Addr)NULL)
1974 objlist_push_tail(list, obj);
1976 /* Add the object to the global fini list in the reverse order. */
1977 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1978 && !obj->on_fini_list) {
1979 objlist_push_head(&list_fini, obj);
1980 obj->on_fini_list = true;
1985 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1989 free_needed_filtees(Needed_Entry *n)
1991 Needed_Entry *needed, *needed1;
1993 for (needed = n; needed != NULL; needed = needed->next) {
1994 if (needed->obj != NULL) {
1995 dlclose(needed->obj);
1999 for (needed = n; needed != NULL; needed = needed1) {
2000 needed1 = needed->next;
2006 unload_filtees(Obj_Entry *obj)
2009 free_needed_filtees(obj->needed_filtees);
2010 obj->needed_filtees = NULL;
2011 free_needed_filtees(obj->needed_aux_filtees);
2012 obj->needed_aux_filtees = NULL;
2013 obj->filtees_loaded = false;
2017 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2018 RtldLockState *lockstate)
2021 for (; needed != NULL; needed = needed->next) {
2022 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2023 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2024 RTLD_LOCAL, lockstate);
2029 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2032 lock_restart_for_upgrade(lockstate);
2033 if (!obj->filtees_loaded) {
2034 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2035 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2036 obj->filtees_loaded = true;
2041 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2045 for (; needed != NULL; needed = needed->next) {
2046 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2047 flags & ~RTLD_LO_NOLOAD);
2048 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2055 * Given a shared object, traverse its list of needed objects, and load
2056 * each of them. Returns 0 on success. Generates an error message and
2057 * returns -1 on failure.
2060 load_needed_objects(Obj_Entry *first, int flags)
2064 for (obj = first; obj != NULL; obj = obj->next) {
2065 if (process_needed(obj, obj->needed, flags) == -1)
2072 load_preload_objects(void)
2074 char *p = ld_preload;
2076 static const char delim[] = " \t:;";
2081 p += strspn(p, delim);
2082 while (*p != '\0') {
2083 size_t len = strcspn(p, delim);
2090 obj = load_object(p, -1, NULL, 0);
2092 return -1; /* XXX - cleanup */
2093 obj->z_interpose = true;
2096 p += strspn(p, delim);
2098 /* Check for the magic tracing function */
2099 symlook_init(&req, RTLD_FUNCTRACE);
2100 res = symlook_obj(&req, obj);
2102 rtld_functrace = (void *)(req.defobj_out->relocbase +
2103 req.sym_out->st_value);
2104 rtld_functrace_obj = req.defobj_out;
2107 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2112 printable_path(const char *path)
2115 return (path == NULL ? "<unknown>" : path);
2119 * Load a shared object into memory, if it is not already loaded. The
2120 * object may be specified by name or by user-supplied file descriptor
2121 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2124 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2128 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2137 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2138 if (object_match_name(obj, name))
2142 path = find_library(name, refobj, &fd);
2150 * search_library_pathfds() opens a fresh file descriptor for the
2151 * library, so there is no need to dup().
2153 } else if (fd_u == -1) {
2155 * If we didn't find a match by pathname, or the name is not
2156 * supplied, open the file and check again by device and inode.
2157 * This avoids false mismatches caused by multiple links or ".."
2160 * To avoid a race, we open the file and use fstat() rather than
2163 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) {
2164 _rtld_error("Cannot open \"%s\"", path);
2169 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2171 _rtld_error("Cannot dup fd");
2176 if (fstat(fd, &sb) == -1) {
2177 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2182 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2183 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2185 if (obj != NULL && name != NULL) {
2186 object_add_name(obj, name);
2191 if (flags & RTLD_LO_NOLOAD) {
2197 /* First use of this object, so we must map it in */
2198 obj = do_load_object(fd, name, path, &sb, flags);
2207 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2214 * but first, make sure that environment variables haven't been
2215 * used to circumvent the noexec flag on a filesystem.
2217 if (dangerous_ld_env) {
2218 if (fstatfs(fd, &fs) != 0) {
2219 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2222 if (fs.f_flags & MNT_NOEXEC) {
2223 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2227 dbg("loading \"%s\"", printable_path(path));
2228 obj = map_object(fd, printable_path(path), sbp);
2233 * If DT_SONAME is present in the object, digest_dynamic2 already
2234 * added it to the object names.
2237 object_add_name(obj, name);
2239 digest_dynamic(obj, 0);
2240 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2241 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2242 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2244 dbg("refusing to load non-loadable \"%s\"", obj->path);
2245 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2246 munmap(obj->mapbase, obj->mapsize);
2252 obj_tail = &obj->next;
2255 linkmap_add(obj); /* for GDB & dlinfo() */
2257 max_stack_flags |= obj->stack_flags;
2260 dbg(" %p .. %p: %s", obj->mapbase,
2261 obj->mapbase + obj->mapsize - 1, obj->path);
2263 dbg(" WARNING: %s has impure text", obj->path);
2264 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2271 obj_from_addr(const void *addr)
2275 for (obj = obj_list; obj != NULL; obj = obj->next) {
2276 if (addr < (void *) obj->mapbase)
2278 if (addr < (void *) (obj->mapbase + obj->mapsize))
2285 * If the main program is defined with a .preinit_array section, call
2286 * each function in order. This must occur before the initialization
2287 * of any shared object or the main program.
2292 Elf_Addr *preinit_addr;
2295 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2296 if (preinit_addr == NULL)
2299 for (index = 0; index < obj_main->preinit_array_num; index++) {
2300 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2301 dbg("calling preinit function for %s at %p", obj_main->path,
2302 (void *)preinit_addr[index]);
2303 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2304 0, 0, obj_main->path);
2305 call_init_pointer(obj_main, preinit_addr[index]);
2311 * Call the finalization functions for each of the objects in "list"
2312 * belonging to the DAG of "root" and referenced once. If NULL "root"
2313 * is specified, every finalization function will be called regardless
2314 * of the reference count and the list elements won't be freed. All of
2315 * the objects are expected to have non-NULL fini functions.
2318 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2322 Elf_Addr *fini_addr;
2325 assert(root == NULL || root->refcount == 1);
2328 * Preserve the current error message since a fini function might
2329 * call into the dynamic linker and overwrite it.
2331 saved_msg = errmsg_save();
2333 STAILQ_FOREACH(elm, list, link) {
2334 if (root != NULL && (elm->obj->refcount != 1 ||
2335 objlist_find(&root->dagmembers, elm->obj) == NULL))
2338 /* Remove object from fini list to prevent recursive invocation. */
2339 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2341 * XXX: If a dlopen() call references an object while the
2342 * fini function is in progress, we might end up trying to
2343 * unload the referenced object in dlclose() or the object
2344 * won't be unloaded although its fini function has been
2347 lock_release(rtld_bind_lock, lockstate);
2350 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2351 * When this happens, DT_FINI_ARRAY is processed first.
2352 * It is also processed backwards. It is possible to encounter
2353 * DT_FINI_ARRAY elements with values of 0 or 1, but they need
2356 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2357 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2358 for (index = elm->obj->fini_array_num - 1; index >= 0; index--) {
2359 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2360 dbg("calling fini array function for %s at %p",
2361 elm->obj->path, (void *)fini_addr[index]);
2362 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2363 (void *)fini_addr[index], 0, 0, elm->obj->path);
2364 call_initfini_pointer(elm->obj, fini_addr[index]);
2368 if (elm->obj->fini != (Elf_Addr)NULL) {
2369 dbg("calling fini function for %s at %p", elm->obj->path,
2370 (void *)elm->obj->fini);
2371 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2372 0, 0, elm->obj->path);
2373 call_initfini_pointer(elm->obj, elm->obj->fini);
2375 wlock_acquire(rtld_bind_lock, lockstate);
2376 /* No need to free anything if process is going down. */
2380 * We must restart the list traversal after every fini call
2381 * because a dlclose() call from the fini function or from
2382 * another thread might have modified the reference counts.
2386 } while (elm != NULL);
2387 errmsg_restore(saved_msg);
2391 * Call the initialization functions for each of the objects in
2392 * "list". All of the objects are expected to have non-NULL init
2396 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2401 Elf_Addr *init_addr;
2405 * Clean init_scanned flag so that objects can be rechecked and
2406 * possibly initialized earlier if any of vectors called below
2407 * cause the change by using dlopen.
2409 for (obj = obj_list; obj != NULL; obj = obj->next)
2410 obj->init_scanned = false;
2413 * Preserve the current error message since an init function might
2414 * call into the dynamic linker and overwrite it.
2416 saved_msg = errmsg_save();
2417 STAILQ_FOREACH(elm, list, link) {
2418 if (elm->obj->init_done) /* Initialized early. */
2422 * Race: other thread might try to use this object before current
2423 * one completes the initilization. Not much can be done here
2424 * without better locking.
2426 elm->obj->init_done = true;
2427 lock_release(rtld_bind_lock, lockstate);
2430 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2431 * When this happens, DT_INIT is processed first.
2432 * It is possible to encounter DT_INIT_ARRAY elements with values
2433 * of 0 or 1, but they need to be ignored.
2435 if (elm->obj->init != (Elf_Addr)NULL) {
2436 dbg("calling init function for %s at %p", elm->obj->path,
2437 (void *)elm->obj->init);
2438 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2439 0, 0, elm->obj->path);
2440 call_initfini_pointer(elm->obj, elm->obj->init);
2442 init_addr = (Elf_Addr *)elm->obj->init_array;
2443 if (init_addr != NULL) {
2444 for (index = 0; index < elm->obj->init_array_num; index++) {
2445 if (init_addr[index] != 0 && init_addr[index] != 1) {
2446 dbg("calling init array function for %s at %p", elm->obj->path,
2447 (void *)init_addr[index]);
2448 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2449 (void *)init_addr[index], 0, 0, elm->obj->path);
2450 call_init_pointer(elm->obj, init_addr[index]);
2454 wlock_acquire(rtld_bind_lock, lockstate);
2456 errmsg_restore(saved_msg);
2460 objlist_clear(Objlist *list)
2464 while (!STAILQ_EMPTY(list)) {
2465 elm = STAILQ_FIRST(list);
2466 STAILQ_REMOVE_HEAD(list, link);
2471 static Objlist_Entry *
2472 objlist_find(Objlist *list, const Obj_Entry *obj)
2476 STAILQ_FOREACH(elm, list, link)
2477 if (elm->obj == obj)
2483 objlist_init(Objlist *list)
2489 objlist_push_head(Objlist *list, Obj_Entry *obj)
2493 elm = NEW(Objlist_Entry);
2495 STAILQ_INSERT_HEAD(list, elm, link);
2499 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2503 elm = NEW(Objlist_Entry);
2505 STAILQ_INSERT_TAIL(list, elm, link);
2509 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2511 Objlist_Entry *elm, *listelm;
2513 STAILQ_FOREACH(listelm, list, link) {
2514 if (listelm->obj == listobj)
2517 elm = NEW(Objlist_Entry);
2519 if (listelm != NULL)
2520 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2522 STAILQ_INSERT_TAIL(list, elm, link);
2526 objlist_remove(Objlist *list, Obj_Entry *obj)
2530 if ((elm = objlist_find(list, obj)) != NULL) {
2531 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2537 * Relocate dag rooted in the specified object.
2538 * Returns 0 on success, or -1 on failure.
2542 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2543 int flags, RtldLockState *lockstate)
2549 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2550 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2559 * Prepare for, or clean after, relocating an object marked with
2560 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
2561 * segments are remapped read-write. After relocations are done, the
2562 * segment's permissions are returned back to the modes specified in
2563 * the phdrs. If any relocation happened, or always for wired
2564 * program, COW is triggered.
2567 reloc_textrel_prot(Obj_Entry *obj, bool before)
2574 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
2576 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
2578 base = obj->relocbase + trunc_page(ph->p_vaddr);
2579 sz = round_page(ph->p_vaddr + ph->p_filesz) -
2580 trunc_page(ph->p_vaddr);
2581 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0);
2583 * Make sure modified text segments are included in the
2584 * core dump since we modified it. This unfortunately causes the
2585 * entire text segment to core-out but we don't have much of a
2586 * choice. We could try to only reenable core dumps on pages
2587 * in which relocations occured but that is likely most of the text
2588 * pages anyway, and even that would not work because the rest of
2589 * the text pages would wind up as a read-only OBJT_DEFAULT object
2590 * (created due to our modifications) backed by the original OBJT_VNODE
2591 * object, and the ELF coredump code is currently only able to dump
2592 * vnode records for pure vnode-backed mappings, not vnode backings
2593 * to memory objects.
2595 if (before == false)
2596 madvise(base, sz, MADV_CORE);
2597 if (mprotect(base, sz, prot) == -1) {
2598 _rtld_error("%s: Cannot write-%sable text segment: %s",
2599 obj->path, before ? "en" : "dis",
2600 rtld_strerror(errno));
2608 * Relocate single object.
2609 * Returns 0 on success, or -1 on failure.
2612 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2613 int flags, RtldLockState *lockstate)
2618 obj->relocated = true;
2620 dbg("relocating \"%s\"", obj->path);
2622 if (obj->symtab == NULL || obj->strtab == NULL ||
2623 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2624 _rtld_error("%s: Shared object has no run-time symbol table",
2629 /* There are relocations to the write-protected text segment. */
2630 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
2633 /* Process the non-PLT non-IFUNC relocations. */
2634 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2637 /* Re-protected the text segment. */
2638 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
2641 /* Set the special PLT or GOT entries. */
2644 /* Process the PLT relocations. */
2645 if (reloc_plt(obj) == -1)
2647 /* Relocate the jump slots if we are doing immediate binding. */
2648 if (obj->bind_now || bind_now)
2649 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2653 * Process the non-PLT IFUNC relocations. The relocations are
2654 * processed in two phases, because IFUNC resolvers may
2655 * reference other symbols, which must be readily processed
2656 * before resolvers are called.
2658 if (obj->non_plt_gnu_ifunc &&
2659 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
2663 * Set up the magic number and version in the Obj_Entry. These
2664 * were checked in the crt1.o from the original ElfKit, so we
2665 * set them for backward compatibility.
2667 obj->magic = RTLD_MAGIC;
2668 obj->version = RTLD_VERSION;
2671 * Set relocated data to read-only status if protection specified
2674 if (obj->relro_size) {
2675 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) {
2676 _rtld_error("%s: Cannot enforce relro relocation: %s",
2677 obj->path, rtld_strerror(errno));
2680 obj->relro_protected = true;
2686 * Relocate newly-loaded shared objects. The argument is a pointer to
2687 * the Obj_Entry for the first such object. All objects from the first
2688 * to the end of the list of objects are relocated. Returns 0 on success,
2692 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2693 int flags, RtldLockState *lockstate)
2698 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2699 error = relocate_object(obj, bind_now, rtldobj, flags,
2708 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2709 * referencing STT_GNU_IFUNC symbols is postponed till the other
2710 * relocations are done. The indirect functions specified as
2711 * ifunc are allowed to call other symbols, so we need to have
2712 * objects relocated before asking for resolution from indirects.
2714 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2715 * instead of the usual lazy handling of PLT slots. It is
2716 * consistent with how GNU does it.
2719 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2720 RtldLockState *lockstate)
2722 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2724 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2725 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2731 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2732 RtldLockState *lockstate)
2736 for (obj = first; obj != NULL; obj = obj->next) {
2737 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2744 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2745 RtldLockState *lockstate)
2749 STAILQ_FOREACH(elm, list, link) {
2750 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2758 * Cleanup procedure. It will be called (by the atexit mechanism) just
2759 * before the process exits.
2764 RtldLockState lockstate;
2766 wlock_acquire(rtld_bind_lock, &lockstate);
2768 objlist_call_fini(&list_fini, NULL, &lockstate);
2769 /* No need to remove the items from the list, since we are exiting. */
2770 if (!libmap_disable)
2772 lock_release(rtld_bind_lock, &lockstate);
2776 * Iterate over a search path, translate each element, and invoke the
2777 * callback on the result.
2780 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2786 path += strspn(path, ":;");
2787 while (*path != '\0') {
2791 len = strcspn(path, ":;");
2792 trans = lm_findn(NULL, path, len);
2794 res = callback(trans, strlen(trans), arg);
2796 res = callback(path, len, arg);
2802 path += strspn(path, ":;");
2808 struct try_library_args {
2816 try_library_path(const char *dir, size_t dirlen, void *param)
2818 struct try_library_args *arg;
2821 if (*dir == '/' || trust) {
2824 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2827 pathname = arg->buffer;
2828 strncpy(pathname, dir, dirlen);
2829 pathname[dirlen] = '/';
2830 strcpy(pathname + dirlen + 1, arg->name);
2832 dbg(" Trying \"%s\"", pathname);
2833 if (access(pathname, F_OK) == 0) { /* We found it */
2834 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2835 strcpy(pathname, arg->buffer);
2843 search_library_path(const char *name, const char *path)
2846 struct try_library_args arg;
2852 arg.namelen = strlen(name);
2853 arg.buffer = xmalloc(PATH_MAX);
2854 arg.buflen = PATH_MAX;
2856 p = path_enumerate(path, try_library_path, &arg);
2865 * Finds the library with the given name using the directory descriptors
2866 * listed in the LD_LIBRARY_PATH_FDS environment variable.
2868 * Returns a freshly-opened close-on-exec file descriptor for the library,
2869 * or -1 if the library cannot be found.
2872 search_library_pathfds(const char *name, const char *path, int *fdp)
2874 char *envcopy, *fdstr, *found, *last_token;
2878 dbg("%s('%s', '%s', fdp)", __func__, name, path);
2880 /* Don't load from user-specified libdirs into setuid binaries. */
2884 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
2888 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
2889 if (name[0] == '/') {
2890 dbg("Absolute path (%s) passed to %s", name, __func__);
2895 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
2896 * copy of the path, as strtok_r rewrites separator tokens
2900 envcopy = xstrdup(path);
2901 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
2902 fdstr = strtok_r(NULL, ":", &last_token)) {
2903 dirfd = parse_libdir(fdstr);
2906 fd = openat(dirfd, name, O_RDONLY | O_CLOEXEC);
2909 len = strlen(fdstr) + strlen(name) + 3;
2910 found = xmalloc(len);
2911 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
2912 _rtld_error("error generating '%d/%s'",
2916 dbg("open('%s') => %d", found, fd);
2927 dlclose(void *handle)
2930 RtldLockState lockstate;
2932 wlock_acquire(rtld_bind_lock, &lockstate);
2933 root = dlcheck(handle);
2935 lock_release(rtld_bind_lock, &lockstate);
2938 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2941 /* Unreference the object and its dependencies. */
2942 root->dl_refcount--;
2944 if (root->refcount == 1) {
2946 * The object will be no longer referenced, so we must unload it.
2947 * First, call the fini functions.
2949 objlist_call_fini(&list_fini, root, &lockstate);
2953 /* Finish cleaning up the newly-unreferenced objects. */
2954 GDB_STATE(RT_DELETE,&root->linkmap);
2955 unload_object(root);
2956 GDB_STATE(RT_CONSISTENT,NULL);
2960 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2961 lock_release(rtld_bind_lock, &lockstate);
2968 char *msg = error_message;
2969 error_message = NULL;
2974 dlopen(const char *name, int mode)
2977 return (rtld_dlopen(name, -1, mode));
2981 fdlopen(int fd, int mode)
2984 return (rtld_dlopen(NULL, fd, mode));
2988 rtld_dlopen(const char *name, int fd, int mode)
2990 RtldLockState lockstate;
2993 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2994 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2995 if (ld_tracing != NULL) {
2996 rlock_acquire(rtld_bind_lock, &lockstate);
2997 if (sigsetjmp(lockstate.env, 0) != 0)
2998 lock_upgrade(rtld_bind_lock, &lockstate);
2999 environ = (char **)*get_program_var_addr("environ", &lockstate);
3000 lock_release(rtld_bind_lock, &lockstate);
3002 lo_flags = RTLD_LO_DLOPEN;
3003 if (mode & RTLD_NODELETE)
3004 lo_flags |= RTLD_LO_NODELETE;
3005 if (mode & RTLD_NOLOAD)
3006 lo_flags |= RTLD_LO_NOLOAD;
3007 if (ld_tracing != NULL)
3008 lo_flags |= RTLD_LO_TRACE;
3010 return (dlopen_object(name, fd, obj_main, lo_flags,
3011 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3015 dlopen_cleanup(Obj_Entry *obj)
3020 if (obj->refcount == 0)
3025 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3026 int mode, RtldLockState *lockstate)
3028 Obj_Entry **old_obj_tail;
3031 RtldLockState mlockstate;
3034 objlist_init(&initlist);
3036 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3037 wlock_acquire(rtld_bind_lock, &mlockstate);
3038 lockstate = &mlockstate;
3040 GDB_STATE(RT_ADD,NULL);
3042 old_obj_tail = obj_tail;
3044 if (name == NULL && fd == -1) {
3048 obj = load_object(name, fd, refobj, lo_flags);
3053 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3054 objlist_push_tail(&list_global, obj);
3055 if (*old_obj_tail != NULL) { /* We loaded something new. */
3056 assert(*old_obj_tail == obj);
3057 if ((lo_flags & RTLD_LO_EARLY) == 0 && obj->static_tls &&
3058 !allocate_tls_offset(obj)) {
3059 _rtld_error("%s: No space available "
3067 result = load_needed_objects(
3069 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
3074 result = rtld_verify_versions(&obj->dagmembers);
3075 if (result != -1 && ld_tracing)
3077 if (result == -1 || relocate_object_dag(obj,
3078 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3079 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3081 dlopen_cleanup(obj);
3083 } else if (lo_flags & RTLD_LO_EARLY) {
3085 * Do not call the init functions for early loaded
3086 * filtees. The image is still not initialized enough
3089 * Our object is found by the global object list and
3090 * will be ordered among all init calls done right
3091 * before transferring control to main.
3094 /* Make list of init functions to call. */
3095 initlist_add_objects(obj, &obj->next, &initlist);
3098 * Process all no_delete objects here, given them own
3099 * DAGs to prevent their dependencies from being unloaded.
3100 * This has to be done after we have loaded all of the
3101 * dependencies, so that we do not miss any.
3104 process_nodelete(obj);
3107 * Bump the reference counts for objects on this DAG. If
3108 * this is the first dlopen() call for the object that was
3109 * already loaded as a dependency, initialize the dag
3115 if ((lo_flags & RTLD_LO_TRACE) != 0)
3118 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3119 obj->z_nodelete) && !obj->ref_nodel) {
3120 dbg("obj %s nodelete", obj->path);
3122 obj->z_nodelete = obj->ref_nodel = true;
3126 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3128 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3130 if ((lo_flags & RTLD_LO_EARLY) == 0) {
3131 map_stacks_exec(lockstate);
3133 distribute_static_tls(&initlist, lockstate);
3136 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3137 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3139 objlist_clear(&initlist);
3140 dlopen_cleanup(obj);
3141 if (lockstate == &mlockstate)
3142 lock_release(rtld_bind_lock, lockstate);
3146 if (!(lo_flags & RTLD_LO_EARLY)) {
3147 /* Call the init functions. */
3148 objlist_call_init(&initlist, lockstate);
3150 objlist_clear(&initlist);
3151 if (lockstate == &mlockstate)
3152 lock_release(rtld_bind_lock, lockstate);
3155 trace_loaded_objects(obj);
3156 if (lockstate == &mlockstate)
3157 lock_release(rtld_bind_lock, lockstate);
3162 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3166 const Obj_Entry *obj, *defobj;
3169 RtldLockState lockstate;
3175 symlook_init(&req, name);
3177 req.flags = flags | SYMLOOK_IN_PLT;
3178 req.lockstate = &lockstate;
3180 rlock_acquire(rtld_bind_lock, &lockstate);
3181 if (sigsetjmp(lockstate.env, 0) != 0)
3182 lock_upgrade(rtld_bind_lock, &lockstate);
3183 if (handle == NULL || handle == RTLD_NEXT ||
3184 handle == RTLD_DEFAULT || handle == RTLD_SELF ||
3185 handle == RTLD_ALL) {
3187 if (handle != RTLD_ALL) {
3188 if ((obj = obj_from_addr(retaddr)) == NULL) {
3189 _rtld_error("Cannot determine caller's shared object");
3190 lock_release(rtld_bind_lock, &lockstate);
3196 if (handle == NULL) { /* Just the caller's shared object. */
3197 res = symlook_obj(&req, obj);
3200 defobj = req.defobj_out;
3202 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3203 handle == RTLD_SELF || /* ... caller included */
3204 handle == RTLD_ALL) { /* All Objects */
3205 if (handle == RTLD_NEXT)
3207 for (; obj != NULL; obj = obj->next) {
3208 res = symlook_obj(&req, obj);
3211 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3213 defobj = req.defobj_out;
3214 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3220 * Search the dynamic linker itself, and possibly resolve the
3221 * symbol from there. This is how the application links to
3222 * dynamic linker services such as dlopen.
3224 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3225 res = symlook_obj(&req, &obj_rtld);
3228 defobj = req.defobj_out;
3232 assert(handle == RTLD_DEFAULT);
3233 res = symlook_default(&req, obj);
3235 defobj = req.defobj_out;
3240 if ((obj = dlcheck(handle)) == NULL) {
3241 lock_release(rtld_bind_lock, &lockstate);
3245 donelist_init(&donelist);
3246 if (obj->mainprog) {
3247 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3248 res = symlook_global(&req, &donelist);
3251 defobj = req.defobj_out;
3254 * Search the dynamic linker itself, and possibly resolve the
3255 * symbol from there. This is how the application links to
3256 * dynamic linker services such as dlopen.
3258 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3259 res = symlook_obj(&req, &obj_rtld);
3262 defobj = req.defobj_out;
3267 /* Search the whole DAG rooted at the given object. */
3268 res = symlook_list(&req, &obj->dagmembers, &donelist);
3271 defobj = req.defobj_out;
3277 lock_release(rtld_bind_lock, &lockstate);
3280 * The value required by the caller is derived from the value
3281 * of the symbol. this is simply the relocated value of the
3284 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3285 return (make_function_pointer(def, defobj));
3286 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3287 return (rtld_resolve_ifunc(defobj, def));
3288 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3289 ti.ti_module = defobj->tlsindex;
3290 ti.ti_offset = def->st_value;
3291 return (__tls_get_addr(&ti));
3293 return (defobj->relocbase + def->st_value);
3296 _rtld_error("Undefined symbol \"%s\"", name);
3297 lock_release(rtld_bind_lock, &lockstate);
3302 dlsym(void *handle, const char *name)
3304 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3309 dlfunc(void *handle, const char *name)
3316 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3322 dlvsym(void *handle, const char *name, const char *version)
3326 ventry.name = version;
3328 ventry.hash = elf_hash(version);
3330 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3335 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3337 const Obj_Entry *obj;
3338 RtldLockState lockstate;
3340 rlock_acquire(rtld_bind_lock, &lockstate);
3341 obj = obj_from_addr(addr);
3343 _rtld_error("No shared object contains address");
3344 lock_release(rtld_bind_lock, &lockstate);
3347 rtld_fill_dl_phdr_info(obj, phdr_info);
3348 lock_release(rtld_bind_lock, &lockstate);
3353 dladdr(const void *addr, Dl_info *info)
3355 const Obj_Entry *obj;
3358 unsigned long symoffset;
3359 RtldLockState lockstate;
3361 rlock_acquire(rtld_bind_lock, &lockstate);
3362 obj = obj_from_addr(addr);
3364 _rtld_error("No shared object contains address");
3365 lock_release(rtld_bind_lock, &lockstate);
3368 info->dli_fname = obj->path;
3369 info->dli_fbase = obj->mapbase;
3370 info->dli_saddr = NULL;
3371 info->dli_sname = NULL;
3374 * Walk the symbol list looking for the symbol whose address is
3375 * closest to the address sent in.
3377 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3378 def = obj->symtab + symoffset;
3381 * For skip the symbol if st_shndx is either SHN_UNDEF or
3384 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3388 * If the symbol is greater than the specified address, or if it
3389 * is further away from addr than the current nearest symbol,
3392 symbol_addr = obj->relocbase + def->st_value;
3393 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3396 /* Update our idea of the nearest symbol. */
3397 info->dli_sname = obj->strtab + def->st_name;
3398 info->dli_saddr = symbol_addr;
3401 if (info->dli_saddr == addr)
3404 lock_release(rtld_bind_lock, &lockstate);
3409 dlinfo(void *handle, int request, void *p)
3411 const Obj_Entry *obj;
3412 RtldLockState lockstate;
3415 rlock_acquire(rtld_bind_lock, &lockstate);
3417 if (handle == NULL || handle == RTLD_SELF) {
3420 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3421 if ((obj = obj_from_addr(retaddr)) == NULL)
3422 _rtld_error("Cannot determine caller's shared object");
3424 obj = dlcheck(handle);
3427 lock_release(rtld_bind_lock, &lockstate);
3433 case RTLD_DI_LINKMAP:
3434 *((struct link_map const **)p) = &obj->linkmap;
3436 case RTLD_DI_ORIGIN:
3437 error = rtld_dirname(obj->path, p);
3440 case RTLD_DI_SERINFOSIZE:
3441 case RTLD_DI_SERINFO:
3442 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3446 _rtld_error("Invalid request %d passed to dlinfo()", request);
3450 lock_release(rtld_bind_lock, &lockstate);
3456 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3459 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3460 phdr_info->dlpi_name = obj->path;
3461 phdr_info->dlpi_phdr = obj->phdr;
3462 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3463 phdr_info->dlpi_tls_modid = obj->tlsindex;
3464 phdr_info->dlpi_tls_data = obj->tlsinit;
3465 phdr_info->dlpi_adds = obj_loads;
3466 phdr_info->dlpi_subs = obj_loads - obj_count;
3470 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3472 struct dl_phdr_info phdr_info;
3473 const Obj_Entry *obj;
3474 RtldLockState bind_lockstate, phdr_lockstate;
3477 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3478 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3482 for (obj = obj_list; obj != NULL; obj = obj->next) {
3483 rtld_fill_dl_phdr_info(obj, &phdr_info);
3484 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3489 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3490 error = callback(&phdr_info, sizeof(phdr_info), param);
3493 lock_release(rtld_bind_lock, &bind_lockstate);
3494 lock_release(rtld_phdr_lock, &phdr_lockstate);
3500 fill_search_info(const char *dir, size_t dirlen, void *param)
3502 struct fill_search_info_args *arg;
3506 if (arg->request == RTLD_DI_SERINFOSIZE) {
3507 arg->serinfo->dls_cnt ++;
3508 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3510 struct dl_serpath *s_entry;
3512 s_entry = arg->serpath;
3513 s_entry->dls_name = arg->strspace;
3514 s_entry->dls_flags = arg->flags;
3516 strncpy(arg->strspace, dir, dirlen);
3517 arg->strspace[dirlen] = '\0';
3519 arg->strspace += dirlen + 1;
3527 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3529 struct dl_serinfo _info;
3530 struct fill_search_info_args args;
3532 args.request = RTLD_DI_SERINFOSIZE;
3533 args.serinfo = &_info;
3535 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3538 path_enumerate(obj->rpath, fill_search_info, &args);
3539 path_enumerate(ld_library_path, fill_search_info, &args);
3540 path_enumerate(obj->runpath, fill_search_info, &args);
3541 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3542 if (!obj->z_nodeflib)
3543 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3546 if (request == RTLD_DI_SERINFOSIZE) {
3547 info->dls_size = _info.dls_size;
3548 info->dls_cnt = _info.dls_cnt;
3552 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3553 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3557 args.request = RTLD_DI_SERINFO;
3558 args.serinfo = info;
3559 args.serpath = &info->dls_serpath[0];
3560 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3562 args.flags = LA_SER_RUNPATH;
3563 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3566 args.flags = LA_SER_LIBPATH;
3567 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3570 args.flags = LA_SER_RUNPATH;
3571 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3574 args.flags = LA_SER_CONFIG;
3575 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3579 args.flags = LA_SER_DEFAULT;
3580 if (!obj->z_nodeflib &&
3581 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3587 rtld_dirname(const char *path, char *bname)
3591 /* Empty or NULL string gets treated as "." */
3592 if (path == NULL || *path == '\0') {
3598 /* Strip trailing slashes */
3599 endp = path + strlen(path) - 1;
3600 while (endp > path && *endp == '/')
3603 /* Find the start of the dir */
3604 while (endp > path && *endp != '/')
3607 /* Either the dir is "/" or there are no slashes */
3609 bname[0] = *endp == '/' ? '/' : '.';
3615 } while (endp > path && *endp == '/');
3618 if (endp - path + 2 > PATH_MAX)
3620 _rtld_error("Filename is too long: %s", path);
3624 strncpy(bname, path, endp - path + 1);
3625 bname[endp - path + 1] = '\0';
3630 rtld_dirname_abs(const char *path, char *base)
3632 char base_rel[PATH_MAX];
3634 if (rtld_dirname(path, base) == -1)
3638 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
3639 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
3640 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
3642 strcpy(base, base_rel);
3647 linkmap_add(Obj_Entry *obj)
3649 struct link_map *l = &obj->linkmap;
3650 struct link_map *prev;
3652 obj->linkmap.l_name = obj->path;
3653 obj->linkmap.l_addr = obj->mapbase;
3654 obj->linkmap.l_ld = obj->dynamic;
3656 if (r_debug.r_map == NULL) {
3662 * Scan to the end of the list, but not past the entry for the
3663 * dynamic linker, which we want to keep at the very end.
3665 for (prev = r_debug.r_map;
3666 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3667 prev = prev->l_next)
3670 /* Link in the new entry. */
3672 l->l_next = prev->l_next;
3673 if (l->l_next != NULL)
3674 l->l_next->l_prev = l;
3679 linkmap_delete(Obj_Entry *obj)
3681 struct link_map *l = &obj->linkmap;
3683 if (l->l_prev == NULL) {
3684 if ((r_debug.r_map = l->l_next) != NULL)
3685 l->l_next->l_prev = NULL;
3689 if ((l->l_prev->l_next = l->l_next) != NULL)
3690 l->l_next->l_prev = l->l_prev;
3694 * Function for the debugger to set a breakpoint on to gain control.
3696 * The two parameters allow the debugger to easily find and determine
3697 * what the runtime loader is doing and to whom it is doing it.
3699 * When the loadhook trap is hit (r_debug_state, set at program
3700 * initialization), the arguments can be found on the stack:
3702 * +8 struct link_map *m
3703 * +4 struct r_debug *rd
3707 r_debug_state(struct r_debug* rd, struct link_map *m)
3710 * The following is a hack to force the compiler to emit calls to
3711 * this function, even when optimizing. If the function is empty,
3712 * the compiler is not obliged to emit any code for calls to it,
3713 * even when marked __noinline. However, gdb depends on those
3716 __asm __volatile("" : : : "memory");
3720 * A function called after init routines have completed. This can be used to
3721 * break before a program's entry routine is called, and can be used when
3722 * main is not available in the symbol table.
3725 _r_debug_postinit(struct link_map *m)
3728 /* See r_debug_state(). */
3729 __asm __volatile("" : : : "memory");
3733 * Get address of the pointer variable in the main program.
3734 * Prefer non-weak symbol over the weak one.
3736 static const void **
3737 get_program_var_addr(const char *name, RtldLockState *lockstate)
3742 symlook_init(&req, name);
3743 req.lockstate = lockstate;
3744 donelist_init(&donelist);
3745 if (symlook_global(&req, &donelist) != 0)
3747 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3748 return ((const void **)make_function_pointer(req.sym_out,
3750 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3751 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3753 return ((const void **)(req.defobj_out->relocbase +
3754 req.sym_out->st_value));
3758 * Set a pointer variable in the main program to the given value. This
3759 * is used to set key variables such as "environ" before any of the
3760 * init functions are called.
3763 set_program_var(const char *name, const void *value)
3767 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3768 dbg("\"%s\": *%p <-- %p", name, addr, value);
3774 * Search the global objects, including dependencies and main object,
3775 * for the given symbol.
3778 symlook_global(SymLook *req, DoneList *donelist)
3781 const Objlist_Entry *elm;
3784 symlook_init_from_req(&req1, req);
3786 /* Search all objects loaded at program start up. */
3787 if (req->defobj_out == NULL ||
3788 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3789 res = symlook_list(&req1, &list_main, donelist);
3790 if (res == 0 && (req->defobj_out == NULL ||
3791 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3792 req->sym_out = req1.sym_out;
3793 req->defobj_out = req1.defobj_out;
3794 assert(req->defobj_out != NULL);
3798 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3799 STAILQ_FOREACH(elm, &list_global, link) {
3800 if (req->defobj_out != NULL &&
3801 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3803 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3804 if (res == 0 && (req->defobj_out == NULL ||
3805 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3806 req->sym_out = req1.sym_out;
3807 req->defobj_out = req1.defobj_out;
3808 assert(req->defobj_out != NULL);
3812 return (req->sym_out != NULL ? 0 : ESRCH);
3816 * This is a special version of getenv which is far more efficient
3817 * at finding LD_ environment vars.
3821 _getenv_ld(const char *id)
3825 int idlen = strlen(id);
3827 if (ld_index == LD_ARY_CACHE)
3829 if (ld_index == 0) {
3830 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) {
3831 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_')
3838 for (i = ld_index - 1; i >= 0; --i) {
3839 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=')
3840 return(ld_ary[i] + idlen + 1);
3846 * Given a symbol name in a referencing object, find the corresponding
3847 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3848 * no definition was found. Returns a pointer to the Obj_Entry of the
3849 * defining object via the reference parameter DEFOBJ_OUT.
3852 symlook_default(SymLook *req, const Obj_Entry *refobj)
3855 const Objlist_Entry *elm;
3859 donelist_init(&donelist);
3860 symlook_init_from_req(&req1, req);
3862 /* Look first in the referencing object if linked symbolically. */
3863 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3864 res = symlook_obj(&req1, refobj);
3866 req->sym_out = req1.sym_out;
3867 req->defobj_out = req1.defobj_out;
3868 assert(req->defobj_out != NULL);
3872 symlook_global(req, &donelist);
3874 /* Search all dlopened DAGs containing the referencing object. */
3875 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3876 if (req->sym_out != NULL &&
3877 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3879 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3880 if (res == 0 && (req->sym_out == NULL ||
3881 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3882 req->sym_out = req1.sym_out;
3883 req->defobj_out = req1.defobj_out;
3884 assert(req->defobj_out != NULL);
3889 * Search the dynamic linker itself, and possibly resolve the
3890 * symbol from there. This is how the application links to
3891 * dynamic linker services such as dlopen.
3893 if (req->sym_out == NULL ||
3894 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3895 res = symlook_obj(&req1, &obj_rtld);
3897 req->sym_out = req1.sym_out;
3898 req->defobj_out = req1.defobj_out;
3899 assert(req->defobj_out != NULL);
3903 return (req->sym_out != NULL ? 0 : ESRCH);
3907 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3910 const Obj_Entry *defobj;
3911 const Objlist_Entry *elm;
3917 STAILQ_FOREACH(elm, objlist, link) {
3918 if (donelist_check(dlp, elm->obj))
3920 symlook_init_from_req(&req1, req);
3921 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3922 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3924 defobj = req1.defobj_out;
3925 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3932 req->defobj_out = defobj;
3939 * Search the chain of DAGS cointed to by the given Needed_Entry
3940 * for a symbol of the given name. Each DAG is scanned completely
3941 * before advancing to the next one. Returns a pointer to the symbol,
3942 * or NULL if no definition was found.
3945 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3948 const Needed_Entry *n;
3949 const Obj_Entry *defobj;
3955 symlook_init_from_req(&req1, req);
3956 for (n = needed; n != NULL; n = n->next) {
3957 if (n->obj == NULL ||
3958 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3960 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3962 defobj = req1.defobj_out;
3963 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3969 req->defobj_out = defobj;
3976 * Search the symbol table of a single shared object for a symbol of
3977 * the given name and version, if requested. Returns a pointer to the
3978 * symbol, or NULL if no definition was found. If the object is
3979 * filter, return filtered symbol from filtee.
3981 * The symbol's hash value is passed in for efficiency reasons; that
3982 * eliminates many recomputations of the hash value.
3985 symlook_obj(SymLook *req, const Obj_Entry *obj)
3989 int flags, res, mres;
3992 * If there is at least one valid hash at this point, we prefer to
3993 * use the faster GNU version if available.
3995 if (obj->valid_hash_gnu)
3996 mres = symlook_obj1_gnu(req, obj);
3997 else if (obj->valid_hash_sysv)
3998 mres = symlook_obj1_sysv(req, obj);
4003 if (obj->needed_filtees != NULL) {
4004 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4005 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4006 donelist_init(&donelist);
4007 symlook_init_from_req(&req1, req);
4008 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
4010 req->sym_out = req1.sym_out;
4011 req->defobj_out = req1.defobj_out;
4015 if (obj->needed_aux_filtees != NULL) {
4016 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4017 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4018 donelist_init(&donelist);
4019 symlook_init_from_req(&req1, req);
4020 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
4022 req->sym_out = req1.sym_out;
4023 req->defobj_out = req1.defobj_out;
4031 /* Symbol match routine common to both hash functions */
4033 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4034 const unsigned long symnum)
4037 const Elf_Sym *symp;
4040 symp = obj->symtab + symnum;
4041 strp = obj->strtab + symp->st_name;
4043 switch (ELF_ST_TYPE(symp->st_info)) {
4049 if (symp->st_value == 0)
4053 if (symp->st_shndx != SHN_UNDEF)
4055 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4056 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4062 if (strcmp(req->name, strp) != 0)
4065 if (req->ventry == NULL) {
4066 if (obj->versyms != NULL) {
4067 verndx = VER_NDX(obj->versyms[symnum]);
4068 if (verndx > obj->vernum) {
4070 "%s: symbol %s references wrong version %d",
4071 obj->path, obj->strtab + symnum, verndx);
4075 * If we are not called from dlsym (i.e. this
4076 * is a normal relocation from unversioned
4077 * binary), accept the symbol immediately if
4078 * it happens to have first version after this
4079 * shared object became versioned. Otherwise,
4080 * if symbol is versioned and not hidden,
4081 * remember it. If it is the only symbol with
4082 * this name exported by the shared object, it
4083 * will be returned as a match by the calling
4084 * function. If symbol is global (verndx < 2)
4085 * accept it unconditionally.
4087 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4088 verndx == VER_NDX_GIVEN) {
4089 result->sym_out = symp;
4092 else if (verndx >= VER_NDX_GIVEN) {
4093 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4095 if (result->vsymp == NULL)
4096 result->vsymp = symp;
4102 result->sym_out = symp;
4105 if (obj->versyms == NULL) {
4106 if (object_match_name(obj, req->ventry->name)) {
4107 _rtld_error("%s: object %s should provide version %s "
4108 "for symbol %s", obj_rtld.path, obj->path,
4109 req->ventry->name, obj->strtab + symnum);
4113 verndx = VER_NDX(obj->versyms[symnum]);
4114 if (verndx > obj->vernum) {
4115 _rtld_error("%s: symbol %s references wrong version %d",
4116 obj->path, obj->strtab + symnum, verndx);
4119 if (obj->vertab[verndx].hash != req->ventry->hash ||
4120 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4122 * Version does not match. Look if this is a
4123 * global symbol and if it is not hidden. If
4124 * global symbol (verndx < 2) is available,
4125 * use it. Do not return symbol if we are
4126 * called by dlvsym, because dlvsym looks for
4127 * a specific version and default one is not
4128 * what dlvsym wants.
4130 if ((req->flags & SYMLOOK_DLSYM) ||
4131 (verndx >= VER_NDX_GIVEN) ||
4132 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4136 result->sym_out = symp;
4141 * Search for symbol using SysV hash function.
4142 * obj->buckets is known not to be NULL at this point; the test for this was
4143 * performed with the obj->valid_hash_sysv assignment.
4146 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4148 unsigned long symnum;
4149 Sym_Match_Result matchres;
4151 matchres.sym_out = NULL;
4152 matchres.vsymp = NULL;
4153 matchres.vcount = 0;
4155 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4156 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4157 if (symnum >= obj->nchains)
4158 return (ESRCH); /* Bad object */
4160 if (matched_symbol(req, obj, &matchres, symnum)) {
4161 req->sym_out = matchres.sym_out;
4162 req->defobj_out = obj;
4166 if (matchres.vcount == 1) {
4167 req->sym_out = matchres.vsymp;
4168 req->defobj_out = obj;
4174 /* Search for symbol using GNU hash function */
4176 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4178 Elf_Addr bloom_word;
4179 const Elf32_Word *hashval;
4181 Sym_Match_Result matchres;
4182 unsigned int h1, h2;
4183 unsigned long symnum;
4185 matchres.sym_out = NULL;
4186 matchres.vsymp = NULL;
4187 matchres.vcount = 0;
4189 /* Pick right bitmask word from Bloom filter array */
4190 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4191 obj->maskwords_bm_gnu];
4193 /* Calculate modulus word size of gnu hash and its derivative */
4194 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4195 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4197 /* Filter out the "definitely not in set" queries */
4198 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4201 /* Locate hash chain and corresponding value element*/
4202 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4205 hashval = &obj->chain_zero_gnu[bucket];
4207 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4208 symnum = hashval - obj->chain_zero_gnu;
4209 if (matched_symbol(req, obj, &matchres, symnum)) {
4210 req->sym_out = matchres.sym_out;
4211 req->defobj_out = obj;
4215 } while ((*hashval++ & 1) == 0);
4216 if (matchres.vcount == 1) {
4217 req->sym_out = matchres.vsymp;
4218 req->defobj_out = obj;
4225 trace_loaded_objects(Obj_Entry *obj)
4227 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4230 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
4233 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL)
4234 fmt1 = "\t%o => %p (%x)\n";
4236 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL)
4237 fmt2 = "\t%o (%x)\n";
4239 list_containers = _getenv_ld("LD_TRACE_LOADED_OBJECTS_ALL");
4241 for (; obj; obj = obj->next) {
4242 Needed_Entry *needed;
4246 if (list_containers && obj->needed != NULL)
4247 rtld_printf("%s:\n", obj->path);
4248 for (needed = obj->needed; needed; needed = needed->next) {
4249 if (needed->obj != NULL) {
4250 if (needed->obj->traced && !list_containers)
4252 needed->obj->traced = true;
4253 path = needed->obj->path;
4257 name = (char *)obj->strtab + needed->name;
4258 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4260 fmt = is_lib ? fmt1 : fmt2;
4261 while ((c = *fmt++) != '\0') {
4287 rtld_putstr(main_local);
4290 rtld_putstr(obj_main->path);
4299 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4312 * Unload a dlopened object and its dependencies from memory and from
4313 * our data structures. It is assumed that the DAG rooted in the
4314 * object has already been unreferenced, and that the object has a
4315 * reference count of 0.
4318 unload_object(Obj_Entry *root)
4323 assert(root->refcount == 0);
4326 * Pass over the DAG removing unreferenced objects from
4327 * appropriate lists.
4329 unlink_object(root);
4331 /* Unmap all objects that are no longer referenced. */
4332 linkp = &obj_list->next;
4333 while ((obj = *linkp) != NULL) {
4334 if (obj->refcount == 0) {
4335 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4337 dbg("unloading \"%s\"", obj->path);
4338 unload_filtees(root);
4339 munmap(obj->mapbase, obj->mapsize);
4340 linkmap_delete(obj);
4351 unlink_object(Obj_Entry *root)
4355 if (root->refcount == 0) {
4356 /* Remove the object from the RTLD_GLOBAL list. */
4357 objlist_remove(&list_global, root);
4359 /* Remove the object from all objects' DAG lists. */
4360 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4361 objlist_remove(&elm->obj->dldags, root);
4362 if (elm->obj != root)
4363 unlink_object(elm->obj);
4369 ref_dag(Obj_Entry *root)
4373 assert(root->dag_inited);
4374 STAILQ_FOREACH(elm, &root->dagmembers, link)
4375 elm->obj->refcount++;
4379 unref_dag(Obj_Entry *root)
4383 assert(root->dag_inited);
4384 STAILQ_FOREACH(elm, &root->dagmembers, link)
4385 elm->obj->refcount--;
4389 * Common code for MD __tls_get_addr().
4392 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset)
4394 Elf_Addr* dtv = *dtvp;
4395 RtldLockState lockstate;
4397 /* Check dtv generation in case new modules have arrived */
4398 if (dtv[0] != tls_dtv_generation) {
4402 wlock_acquire(rtld_bind_lock, &lockstate);
4403 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4405 if (to_copy > tls_max_index)
4406 to_copy = tls_max_index;
4407 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4408 newdtv[0] = tls_dtv_generation;
4409 newdtv[1] = tls_max_index;
4411 lock_release(rtld_bind_lock, &lockstate);
4412 dtv = *dtvp = newdtv;
4415 /* Dynamically allocate module TLS if necessary */
4416 if (!dtv[index + 1]) {
4417 /* Signal safe, wlock will block out signals. */
4418 wlock_acquire(rtld_bind_lock, &lockstate);
4419 if (!dtv[index + 1])
4420 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4421 lock_release(rtld_bind_lock, &lockstate);
4423 return ((void *)(dtv[index + 1] + offset));
4426 #if defined(RTLD_STATIC_TLS_VARIANT_II)
4429 * Allocate the static TLS area. Return a pointer to the TCB. The
4430 * static area is based on negative offsets relative to the tcb.
4432 * The TCB contains an errno pointer for the system call layer, but because
4433 * we are the RTLD we really have no idea how the caller was compiled so
4434 * the information has to be passed in. errno can either be:
4436 * type 0 errno is a simple non-TLS global pointer.
4437 * (special case for e.g. libc_rtld)
4438 * type 1 errno accessed by GOT entry (dynamically linked programs)
4439 * type 2 errno accessed by %gs:OFFSET (statically linked programs)
4442 allocate_tls(Obj_Entry *objs)
4447 struct tls_tcb *tcb;
4452 * Allocate the new TCB. static TLS storage is placed just before the
4453 * TCB to support the %gs:OFFSET (negative offset) model.
4455 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
4456 ~RTLD_STATIC_TLS_ALIGN_MASK;
4457 tcb = malloc(data_size + sizeof(*tcb));
4458 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */
4460 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr);
4461 dtv = malloc(dtv_size);
4462 bzero(dtv, dtv_size);
4464 #ifdef RTLD_TCB_HAS_SELF_POINTER
4465 tcb->tcb_self = tcb;
4468 tcb->tcb_pthread = NULL;
4470 dtv[0] = tls_dtv_generation;
4471 dtv[1] = tls_max_index;
4473 for (obj = objs; obj; obj = obj->next) {
4474 if (obj->tlsoffset) {
4475 addr = (Elf_Addr)tcb - obj->tlsoffset;
4476 memset((void *)(addr + obj->tlsinitsize),
4477 0, obj->tlssize - obj->tlsinitsize);
4479 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4480 obj->static_tls_copied = true;
4482 dtv[obj->tlsindex + 1] = addr;
4489 free_tls(struct tls_tcb *tcb)
4493 Elf_Addr tls_start, tls_end;
4496 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
4497 ~RTLD_STATIC_TLS_ALIGN_MASK;
4501 tls_end = (Elf_Addr)tcb;
4502 tls_start = (Elf_Addr)tcb - data_size;
4503 for (i = 0; i < dtv_size; i++) {
4504 if (dtv[i+2] != 0 && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) {
4505 free((void *)dtv[i+2]);
4510 free((void*) tls_start);
4514 #error "Unsupported TLS layout"
4518 * Allocate TLS block for module with given index.
4521 allocate_module_tls(int index)
4526 for (obj = obj_list; obj; obj = obj->next) {
4527 if (obj->tlsindex == index)
4531 _rtld_error("Can't find module with TLS index %d", index);
4535 p = malloc(obj->tlssize);
4537 _rtld_error("Cannot allocate TLS block for index %d", index);
4540 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4541 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4547 allocate_tls_offset(Obj_Entry *obj)
4554 if (obj->tlssize == 0) {
4555 obj->tls_done = true;
4559 if (obj->tlsindex == 1)
4560 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4562 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4563 obj->tlssize, obj->tlsalign);
4566 * If we have already fixed the size of the static TLS block, we
4567 * must stay within that size. When allocating the static TLS, we
4568 * leave a small amount of space spare to be used for dynamically
4569 * loading modules which use static TLS.
4571 if (tls_static_space) {
4572 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4576 tls_last_offset = obj->tlsoffset = off;
4577 tls_last_size = obj->tlssize;
4578 obj->tls_done = true;
4584 free_tls_offset(Obj_Entry *obj)
4586 #ifdef RTLD_STATIC_TLS_VARIANT_II
4588 * If we were the last thing to allocate out of the static TLS
4589 * block, we give our space back to the 'allocator'. This is a
4590 * simplistic workaround to allow libGL.so.1 to be loaded and
4591 * unloaded multiple times. We only handle the Variant II
4592 * mechanism for now - this really needs a proper allocator.
4594 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4595 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4596 tls_last_offset -= obj->tlssize;
4603 _rtld_allocate_tls(void)
4605 struct tls_tcb *new_tcb;
4606 RtldLockState lockstate;
4608 wlock_acquire(rtld_bind_lock, &lockstate);
4609 new_tcb = allocate_tls(obj_list);
4610 lock_release(rtld_bind_lock, &lockstate);
4616 _rtld_free_tls(struct tls_tcb *tcb)
4618 RtldLockState lockstate;
4620 wlock_acquire(rtld_bind_lock, &lockstate);
4622 lock_release(rtld_bind_lock, &lockstate);
4626 object_add_name(Obj_Entry *obj, const char *name)
4632 entry = malloc(sizeof(Name_Entry) + len);
4634 if (entry != NULL) {
4635 strcpy(entry->name, name);
4636 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4641 object_match_name(const Obj_Entry *obj, const char *name)
4645 STAILQ_FOREACH(entry, &obj->names, link) {
4646 if (strcmp(name, entry->name) == 0)
4653 locate_dependency(const Obj_Entry *obj, const char *name)
4655 const Objlist_Entry *entry;
4656 const Needed_Entry *needed;
4658 STAILQ_FOREACH(entry, &list_main, link) {
4659 if (object_match_name(entry->obj, name))
4663 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4664 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4665 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4667 * If there is DT_NEEDED for the name we are looking for,
4668 * we are all set. Note that object might not be found if
4669 * dependency was not loaded yet, so the function can
4670 * return NULL here. This is expected and handled
4671 * properly by the caller.
4673 return (needed->obj);
4676 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4682 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4683 const Elf_Vernaux *vna)
4685 const Elf_Verdef *vd;
4686 const char *vername;
4688 vername = refobj->strtab + vna->vna_name;
4689 vd = depobj->verdef;
4691 _rtld_error("%s: version %s required by %s not defined",
4692 depobj->path, vername, refobj->path);
4696 if (vd->vd_version != VER_DEF_CURRENT) {
4697 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4698 depobj->path, vd->vd_version);
4701 if (vna->vna_hash == vd->vd_hash) {
4702 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4703 ((char *)vd + vd->vd_aux);
4704 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4707 if (vd->vd_next == 0)
4709 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4711 if (vna->vna_flags & VER_FLG_WEAK)
4713 _rtld_error("%s: version %s required by %s not found",
4714 depobj->path, vername, refobj->path);
4719 rtld_verify_object_versions(Obj_Entry *obj)
4721 const Elf_Verneed *vn;
4722 const Elf_Verdef *vd;
4723 const Elf_Verdaux *vda;
4724 const Elf_Vernaux *vna;
4725 const Obj_Entry *depobj;
4726 int maxvernum, vernum;
4728 if (obj->ver_checked)
4730 obj->ver_checked = true;
4734 * Walk over defined and required version records and figure out
4735 * max index used by any of them. Do very basic sanity checking
4739 while (vn != NULL) {
4740 if (vn->vn_version != VER_NEED_CURRENT) {
4741 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4742 obj->path, vn->vn_version);
4745 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4747 vernum = VER_NEED_IDX(vna->vna_other);
4748 if (vernum > maxvernum)
4750 if (vna->vna_next == 0)
4752 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4754 if (vn->vn_next == 0)
4756 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4760 while (vd != NULL) {
4761 if (vd->vd_version != VER_DEF_CURRENT) {
4762 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4763 obj->path, vd->vd_version);
4766 vernum = VER_DEF_IDX(vd->vd_ndx);
4767 if (vernum > maxvernum)
4769 if (vd->vd_next == 0)
4771 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4778 * Store version information in array indexable by version index.
4779 * Verify that object version requirements are satisfied along the
4782 obj->vernum = maxvernum + 1;
4783 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4786 while (vd != NULL) {
4787 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4788 vernum = VER_DEF_IDX(vd->vd_ndx);
4789 assert(vernum <= maxvernum);
4790 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4791 obj->vertab[vernum].hash = vd->vd_hash;
4792 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4793 obj->vertab[vernum].file = NULL;
4794 obj->vertab[vernum].flags = 0;
4796 if (vd->vd_next == 0)
4798 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4802 while (vn != NULL) {
4803 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4806 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4808 if (check_object_provided_version(obj, depobj, vna))
4810 vernum = VER_NEED_IDX(vna->vna_other);
4811 assert(vernum <= maxvernum);
4812 obj->vertab[vernum].hash = vna->vna_hash;
4813 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4814 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4815 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4816 VER_INFO_HIDDEN : 0;
4817 if (vna->vna_next == 0)
4819 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4821 if (vn->vn_next == 0)
4823 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4829 rtld_verify_versions(const Objlist *objlist)
4831 Objlist_Entry *entry;
4835 STAILQ_FOREACH(entry, objlist, link) {
4837 * Skip dummy objects or objects that have their version requirements
4840 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4842 if (rtld_verify_object_versions(entry->obj) == -1) {
4844 if (ld_tracing == NULL)
4848 if (rc == 0 || ld_tracing != NULL)
4849 rc = rtld_verify_object_versions(&obj_rtld);
4854 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4859 vernum = VER_NDX(obj->versyms[symnum]);
4860 if (vernum >= obj->vernum) {
4861 _rtld_error("%s: symbol %s has wrong verneed value %d",
4862 obj->path, obj->strtab + symnum, vernum);
4863 } else if (obj->vertab[vernum].hash != 0) {
4864 return &obj->vertab[vernum];
4871 _rtld_get_stack_prot(void)
4874 return (stack_prot);
4878 map_stacks_exec(RtldLockState *lockstate)
4882 * Stack protection must be implemented in the kernel before the dynamic
4883 * linker can handle PT_GNU_STACK sections.
4884 * The following is the FreeBSD implementation of map_stacks_exec()
4885 * void (*thr_map_stacks_exec)(void);
4887 * if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4889 * thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4890 * get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4891 * if (thr_map_stacks_exec != NULL) {
4892 * stack_prot |= PROT_EXEC;
4893 * thr_map_stacks_exec();
4899 * Only called after all primary shared libraries are loaded (EARLY is
4900 * not set). Resolves the static TLS distribution function at first-call.
4901 * This is typically a weak libc symbol that is overrideen by the threading
4905 distribute_static_tls(Objlist *list, RtldLockState *lockstate)
4909 static void (*dtlsfunc)(size_t, void *, size_t, size_t);
4912 * First time, resolve "_pthread_distribute_static_tls".
4914 if (dtlsfunc == NULL) {
4915 dtlsfunc = (void *)dlfunc(RTLD_ALL,
4916 "_pthread_distribute_static_tls");
4917 if (dtlsfunc == NULL)
4922 * Initialize static TLS data for the object list using the callback
4923 * function (to either libc or pthreads).
4925 STAILQ_FOREACH(elm, list, link) {
4927 if (/*obj->marker ||*/ !obj->tls_done || obj->static_tls_copied)
4929 dtlsfunc(obj->tlsoffset, obj->tlsinit,
4930 obj->tlsinitsize, obj->tlssize);
4931 obj->static_tls_copied = true;
4936 symlook_init(SymLook *dst, const char *name)
4939 bzero(dst, sizeof(*dst));
4941 dst->hash = elf_hash(name);
4942 dst->hash_gnu = gnu_hash(name);
4946 symlook_init_from_req(SymLook *dst, const SymLook *src)
4949 dst->name = src->name;
4950 dst->hash = src->hash;
4951 dst->hash_gnu = src->hash_gnu;
4952 dst->ventry = src->ventry;
4953 dst->flags = src->flags;
4954 dst->defobj_out = NULL;
4955 dst->sym_out = NULL;
4956 dst->lockstate = src->lockstate;
4961 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
4964 parse_libdir(const char *str)
4966 static const int RADIX = 10; /* XXXJA: possibly support hex? */
4973 for (c = *str; c != '\0'; c = *++str) {
4974 if (c < '0' || c > '9')
4981 /* Make sure we actually parsed something. */
4983 _rtld_error("failed to parse directory FD from '%s'", str);
4989 #ifdef ENABLE_OSRELDATE
4991 * Overrides for libc_pic-provided functions.
4995 __getosreldate(void)
5005 oid[1] = KERN_OSRELDATE;
5007 len = sizeof(osrel);
5008 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5009 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5016 * No unresolved symbols for rtld.
5019 __pthread_cxa_finalize(struct dl_phdr_info *a)
5024 rtld_strerror(int errnum)
5027 if (errnum < 0 || errnum >= sys_nerr)
5028 return ("Unknown error");
5029 return (sys_errlist[errnum]);