2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * Copyright 2009, 2010, 2011 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 **,
84 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *);
85 static void digest_dynamic(Obj_Entry *, int);
86 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
87 static Obj_Entry *dlcheck(void *);
88 static Obj_Entry *dlopen_object(const char *name, Obj_Entry *refobj,
89 int lo_flags, int mode);
90 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
91 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
92 static bool donelist_check(DoneList *, const Obj_Entry *);
93 static void errmsg_restore(char *);
94 static char *errmsg_save(void);
95 static void *fill_search_info(const char *, size_t, void *);
96 static char *find_library(const char *, const Obj_Entry *);
97 static const char *gethints(void);
98 static void init_dag(Obj_Entry *);
99 static void init_rtld(caddr_t, Elf_Auxinfo **);
100 static void initlist_add_neededs(Needed_Entry *, Objlist *);
101 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
102 static bool is_exported(const Elf_Sym *);
103 static void linkmap_add(Obj_Entry *);
104 static void linkmap_delete(Obj_Entry *);
105 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
106 static void unload_filtees(Obj_Entry *);
107 static int load_needed_objects(Obj_Entry *, int);
108 static int load_preload_objects(void);
109 static Obj_Entry *load_object(const char *, const Obj_Entry *, int);
110 static void map_stacks_exec(RtldLockState *);
111 static Obj_Entry *obj_from_addr(const void *);
112 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
113 static void objlist_call_init(Objlist *, RtldLockState *);
114 static void preinitialize_main_object (void);
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_remove(Objlist *, Obj_Entry *);
121 static void *path_enumerate(const char *, path_enum_proc, void *);
122 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, RtldLockState *);
123 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
124 RtldLockState *lockstate);
125 static int rtld_dirname(const char *, char *);
126 static int rtld_dirname_abs(const char *, char *);
127 static void rtld_exit(void);
128 static char *search_library_path(const char *, const char *);
129 static const void **get_program_var_addr(const char *, RtldLockState *);
130 static void set_program_var(const char *, const void *);
131 static int symlook_default(SymLook *, const Obj_Entry *refobj);
132 static int symlook_global(SymLook *, DoneList *);
133 static void symlook_init_from_req(SymLook *, const SymLook *);
134 static int symlook_list(SymLook *, const Objlist *, DoneList *);
135 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
136 static int symlook_obj1(SymLook *, const Obj_Entry *);
137 static int symlook_obj2(SymLook *, const Obj_Entry *);
138 static void trace_loaded_objects(Obj_Entry *);
139 static void unlink_object(Obj_Entry *);
140 static void unload_object(Obj_Entry *);
141 static void unref_dag(Obj_Entry *);
142 static void ref_dag(Obj_Entry *);
143 static int origin_subst_one(char **, const char *, const char *,
144 const char *, char *);
145 static char *origin_subst(const char *, const char *);
146 static int rtld_verify_versions(const Objlist *);
147 static int rtld_verify_object_versions(Obj_Entry *);
148 static void object_add_name(Obj_Entry *, const char *);
149 static int object_match_name(const Obj_Entry *, const char *);
150 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
151 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
152 struct dl_phdr_info *phdr_info);
153 static uint_fast32_t gnu_hash (const char *);
154 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
155 const unsigned long);
157 void r_debug_state(struct r_debug *, struct link_map *) __noinline;
162 static char *error_message; /* Message for dlerror(), or NULL */
163 struct r_debug r_debug; /* for GDB; */
164 static bool libmap_disable; /* Disable libmap */
165 static bool ld_loadfltr; /* Immediate filters processing */
166 static char *libmap_override; /* Maps to use in addition to libmap.conf */
167 static bool trust; /* False for setuid and setgid programs */
168 static bool dangerous_ld_env; /* True if environment variables have been
169 used to affect the libraries loaded */
170 static const char *ld_bind_now; /* Environment variable for immediate binding */
171 static const char *ld_debug; /* Environment variable for debugging */
172 static const char *ld_library_path; /* Environment variable for search path */
173 static char *ld_preload; /* Environment variable for libraries to
175 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */
176 static const char *ld_tracing; /* Called from ldd to print libs */
177 static const char *ld_utrace; /* Use utrace() to log events. */
178 static int (*rtld_functrace)( /* Optional function call tracing hook */
179 const char *caller_obj,
180 const char *callee_obj,
181 const char *callee_func,
183 static const Obj_Entry *rtld_functrace_obj; /* Object thereof */
184 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
185 static Obj_Entry **obj_tail; /* Link field of last object in list */
186 static Obj_Entry **preload_tail;
187 static Obj_Entry *obj_main; /* The main program shared object */
188 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
189 static unsigned int obj_count; /* Number of objects in obj_list */
190 static unsigned int obj_loads; /* Number of objects in obj_list */
192 static int ld_resident; /* Non-zero if resident */
193 static const char *ld_ary[LD_ARY_CACHE];
195 static Objlist initlist;
197 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
198 STAILQ_HEAD_INITIALIZER(list_global);
199 static Objlist list_main = /* Objects loaded at program startup */
200 STAILQ_HEAD_INITIALIZER(list_main);
201 static Objlist list_fini = /* Objects needing fini() calls */
202 STAILQ_HEAD_INITIALIZER(list_fini);
204 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */
206 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
208 extern Elf_Dyn _DYNAMIC;
209 #pragma weak _DYNAMIC
210 #ifndef RTLD_IS_DYNAMIC
211 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
214 #ifdef ENABLE_OSRELDATE
218 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
219 static int max_stack_flags;
222 * These are the functions the dynamic linker exports to application
223 * programs. They are the only symbols the dynamic linker is willing
224 * to export from itself.
226 static func_ptr_type exports[] = {
227 (func_ptr_type) &_rtld_error,
228 (func_ptr_type) &dlclose,
229 (func_ptr_type) &dlerror,
230 (func_ptr_type) &dlopen,
231 (func_ptr_type) &dlfunc,
232 (func_ptr_type) &dlsym,
233 (func_ptr_type) &dlvsym,
234 (func_ptr_type) &dladdr,
235 (func_ptr_type) &dlinfo,
236 (func_ptr_type) &dl_iterate_phdr,
238 (func_ptr_type) &___tls_get_addr,
240 (func_ptr_type) &__tls_get_addr,
241 (func_ptr_type) &__tls_get_addr_tcb,
242 (func_ptr_type) &_rtld_allocate_tls,
243 (func_ptr_type) &_rtld_free_tls,
244 (func_ptr_type) &_rtld_call_init,
245 (func_ptr_type) &_rtld_thread_init,
246 (func_ptr_type) &_rtld_addr_phdr,
247 (func_ptr_type) &_rtld_get_stack_prot,
252 * Global declarations normally provided by crt1. The dynamic linker is
253 * not built with crt1, so we have to provide them ourselves.
259 * Used to pass argc, argv to init functions.
265 * Globals to control TLS allocation.
267 size_t tls_last_offset; /* Static TLS offset of last module */
268 size_t tls_last_size; /* Static TLS size of last module */
269 size_t tls_static_space; /* Static TLS space allocated */
270 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
271 int tls_max_index = 1; /* Largest module index allocated */
274 * Fill in a DoneList with an allocation large enough to hold all of
275 * the currently-loaded objects. Keep this as a macro since it calls
276 * alloca and we want that to occur within the scope of the caller.
278 #define donelist_init(dlp) \
279 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
280 assert((dlp)->objs != NULL), \
281 (dlp)->num_alloc = obj_count, \
284 #define UTRACE_DLOPEN_START 1
285 #define UTRACE_DLOPEN_STOP 2
286 #define UTRACE_DLCLOSE_START 3
287 #define UTRACE_DLCLOSE_STOP 4
288 #define UTRACE_LOAD_OBJECT 5
289 #define UTRACE_UNLOAD_OBJECT 6
290 #define UTRACE_ADD_RUNDEP 7
291 #define UTRACE_PRELOAD_FINISHED 8
292 #define UTRACE_INIT_CALL 9
293 #define UTRACE_FINI_CALL 10
296 char sig[4]; /* 'RTLD' */
299 void *mapbase; /* Used for 'parent' and 'init/fini' */
301 int refcnt; /* Used for 'mode' */
302 char name[MAXPATHLEN];
305 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
306 if (ld_utrace != NULL) \
307 ld_utrace_log(e, h, mb, ms, r, n); \
311 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
312 int refcnt, const char *name)
314 struct utrace_rtld ut;
322 ut.mapbase = mapbase;
323 ut.mapsize = mapsize;
325 bzero(ut.name, sizeof(ut.name));
327 strlcpy(ut.name, name, sizeof(ut.name));
328 utrace(&ut, sizeof(ut));
332 * Main entry point for dynamic linking. The first argument is the
333 * stack pointer. The stack is expected to be laid out as described
334 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
335 * Specifically, the stack pointer points to a word containing
336 * ARGC. Following that in the stack is a null-terminated sequence
337 * of pointers to argument strings. Then comes a null-terminated
338 * sequence of pointers to environment strings. Finally, there is a
339 * sequence of "auxiliary vector" entries.
341 * The second argument points to a place to store the dynamic linker's
342 * exit procedure pointer and the third to a place to store the main
345 * The return value is the main program's entry point.
348 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
350 Elf_Auxinfo *aux_info[AT_COUNT];
358 Objlist_Entry *entry;
361 /* marino: DO NOT MOVE THESE VARIABLES TO _rtld
362 Obj_Entry **preload_tail;
364 from global to here. It will break the DWARF2 unwind scheme.
365 The system compilers were unaffected, but not gcc 4.6
369 * On entry, the dynamic linker itself has not been relocated yet.
370 * Be very careful not to reference any global data until after
371 * init_rtld has returned. It is OK to reference file-scope statics
372 * and string constants, and to call static and global functions.
375 /* Find the auxiliary vector on the stack. */
378 sp += argc + 1; /* Skip over arguments and NULL terminator */
382 * If we aren't already resident we have to dig out some more info.
383 * Note that auxinfo does not exist when we are resident.
385 * I'm not sure about the ld_resident check. It seems to read zero
386 * prior to relocation, which is what we want. When running from a
387 * resident copy everything will be relocated so we are definitely
390 if (ld_resident == 0) {
391 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
393 aux = (Elf_Auxinfo *) sp;
395 /* Digest the auxiliary vector. */
396 for (i = 0; i < AT_COUNT; i++)
398 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
399 if (auxp->a_type < AT_COUNT)
400 aux_info[auxp->a_type] = auxp;
403 /* Initialize and relocate ourselves. */
404 assert(aux_info[AT_BASE] != NULL);
405 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
408 ld_index = 0; /* don't use old env cache in case we are resident */
409 __progname = obj_rtld.path;
410 argv0 = argv[0] != NULL ? argv[0] : "(null)";
415 trust = !issetugid();
417 ld_bind_now = _getenv_ld("LD_BIND_NOW");
419 * If the process is tainted, then we un-set the dangerous environment
420 * variables. The process will be marked as tainted until setuid(2)
421 * is called. If any child process calls setuid(2) we do not want any
422 * future processes to honor the potentially un-safe variables.
425 if ( unsetenv("LD_DEBUG")
426 || unsetenv("LD_PRELOAD")
427 || unsetenv("LD_LIBRARY_PATH")
428 || unsetenv("LD_ELF_HINTS_PATH")
429 || unsetenv("LD_LIBMAP")
430 || unsetenv("LD_LIBMAP_DISABLE")
431 || unsetenv("LD_LOADFLTR")
433 _rtld_error("environment corrupt; aborting");
437 ld_debug = _getenv_ld("LD_DEBUG");
438 libmap_disable = _getenv_ld("LD_LIBMAP_DISABLE") != NULL;
439 libmap_override = (char *)_getenv_ld("LD_LIBMAP");
440 ld_library_path = _getenv_ld("LD_LIBRARY_PATH");
441 ld_preload = (char *)_getenv_ld("LD_PRELOAD");
442 ld_elf_hints_path = _getenv_ld("LD_ELF_HINTS_PATH");
443 ld_loadfltr = _getenv_ld("LD_LOADFLTR") != NULL;
444 dangerous_ld_env = (ld_library_path != NULL)
445 || (ld_preload != NULL)
446 || (ld_elf_hints_path != NULL)
448 || (libmap_override != NULL)
451 ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS");
452 ld_utrace = _getenv_ld("LD_UTRACE");
454 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
455 ld_elf_hints_path = _PATH_ELF_HINTS;
457 if (ld_debug != NULL && *ld_debug != '\0')
459 dbg("%s is initialized, base address = %p", __progname,
460 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
461 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
462 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
464 dbg("initializing thread locks");
468 * If we are resident we can skip work that we have already done.
469 * Note that the stack is reset and there is no Elf_Auxinfo
470 * when running from a resident image, and the static globals setup
471 * between here and resident_skip will have already been setup.
477 * Load the main program, or process its program header if it is
480 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
481 int fd = aux_info[AT_EXECFD]->a_un.a_val;
482 dbg("loading main program");
483 obj_main = map_object(fd, argv0, NULL);
485 if (obj_main == NULL)
487 max_stack_flags = obj->stack_flags;
488 } else { /* Main program already loaded. */
489 const Elf_Phdr *phdr;
493 dbg("processing main program's program header");
494 assert(aux_info[AT_PHDR] != NULL);
495 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
496 assert(aux_info[AT_PHNUM] != NULL);
497 phnum = aux_info[AT_PHNUM]->a_un.a_val;
498 assert(aux_info[AT_PHENT] != NULL);
499 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
500 assert(aux_info[AT_ENTRY] != NULL);
501 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
502 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
506 char buf[MAXPATHLEN];
507 if (aux_info[AT_EXECPATH] != NULL) {
510 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
511 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
512 if (kexecpath[0] == '/')
513 obj_main->path = kexecpath;
514 else if (getcwd(buf, sizeof(buf)) == NULL ||
515 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
516 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
517 obj_main->path = xstrdup(argv0);
519 obj_main->path = xstrdup(buf);
521 char resolved[MAXPATHLEN];
522 dbg("No AT_EXECPATH");
523 if (argv0[0] == '/') {
524 if (realpath(argv0, resolved) != NULL)
525 obj_main->path = xstrdup(resolved);
527 obj_main->path = xstrdup(argv0);
529 if (getcwd(buf, sizeof(buf)) != NULL
530 && strlcat(buf, "/", sizeof(buf)) < sizeof(buf)
531 && strlcat(buf, argv0, sizeof (buf)) < sizeof(buf)
532 && access(buf, R_OK) == 0
533 && realpath(buf, resolved) != NULL)
534 obj_main->path = xstrdup(resolved);
536 obj_main->path = xstrdup(argv0);
539 dbg("obj_main path %s", obj_main->path);
540 obj_main->mainprog = true;
542 if (aux_info[AT_STACKPROT] != NULL &&
543 aux_info[AT_STACKPROT]->a_un.a_val != 0)
544 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
547 * Get the actual dynamic linker pathname from the executable if
548 * possible. (It should always be possible.) That ensures that
549 * gdb will find the right dynamic linker even if a non-standard
552 if (obj_main->interp != NULL &&
553 strcmp(obj_main->interp, obj_rtld.path) != 0) {
555 obj_rtld.path = xstrdup(obj_main->interp);
556 __progname = obj_rtld.path;
559 digest_dynamic(obj_main, 0);
561 linkmap_add(obj_main);
562 linkmap_add(&obj_rtld);
564 /* Link the main program into the list of objects. */
565 *obj_tail = obj_main;
566 obj_tail = &obj_main->next;
570 /* Initialize a fake symbol for resolving undefined weak references. */
571 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
572 sym_zero.st_shndx = SHN_UNDEF;
573 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
576 libmap_disable = (bool)lm_init(libmap_override);
578 dbg("loading LD_PRELOAD libraries");
579 if (load_preload_objects() == -1)
581 preload_tail = obj_tail;
583 dbg("loading needed objects");
584 if (load_needed_objects(obj_main, 0) == -1)
587 /* Make a list of all objects loaded at startup. */
588 for (obj = obj_list; obj != NULL; obj = obj->next) {
589 objlist_push_tail(&list_main, obj);
593 dbg("checking for required versions");
594 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
599 if (ld_tracing) { /* We're done */
600 trace_loaded_objects(obj_main);
604 if (ld_resident) /* XXX clean this up! */
607 if (_getenv_ld("LD_DUMP_REL_PRE") != NULL) {
608 dump_relocations(obj_main);
612 /* setup TLS for main thread */
613 dbg("initializing initial thread local storage");
614 STAILQ_FOREACH(entry, &list_main, link) {
616 * Allocate all the initial objects out of the static TLS
617 * block even if they didn't ask for it.
619 allocate_tls_offset(entry->obj);
622 tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA;
625 * Do not try to allocate the TLS here, let libc do it itself.
626 * (crt1 for the program will call _init_tls())
629 if (relocate_objects(obj_main,
630 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld, 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");
678 if (resolve_objects_ifunc(obj_main,
679 ld_bind_now != NULL && *ld_bind_now != '\0', NULL) == -1)
683 * Do NOT call the initlist here, give libc a chance to set up
684 * the initial TLS segment. crt1 will then call _rtld_call_init().
687 dbg("transferring control to program entry point = %p", obj_main->entry);
689 /* Return the exit procedure and the program entry point. */
690 *exit_proc = rtld_exit;
692 return (func_ptr_type) obj_main->entry;
696 * Call the initialization list for dynamically loaded libraries.
697 * (called from crt1.c).
700 _rtld_call_init(void)
702 RtldLockState lockstate;
705 if (!obj_main->note_present && obj_main->valid_hash_gnu) {
707 * The use of a linker script with a PHDRS directive that does not include
708 * PT_NOTE will block the crt_no_init note. In this case we'll look for the
709 * recently added GNU hash dynamic tag which gets built by default. It is
710 * extremely unlikely to find a pre-3.1 binary without a PT_NOTE header and
711 * a gnu hash tag. If gnu hash found, consider binary to use new crt code.
713 obj_main->crt_no_init = true;
714 dbg("Setting crt_no_init without presence of PT_NOTE header");
717 wlock_acquire(rtld_bind_lock, &lockstate);
718 if (obj_main->crt_no_init) {
719 preinitialize_main_object();
723 * Make sure we don't call the main program's init and fini functions
724 * for binaries linked with old crt1 which calls _init itself.
726 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
727 obj_main->init_array = obj_main->fini_array = (Elf_Addr)NULL;
729 objlist_call_init(&initlist, &lockstate);
730 objlist_clear(&initlist);
731 dbg("loading filtees");
732 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
733 if (ld_loadfltr || obj->z_loadfltr)
734 load_filtees(obj, 0, &lockstate);
736 lock_release(rtld_bind_lock, &lockstate);
740 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
745 ptr = (void *)make_function_pointer(def, obj);
746 target = ((Elf_Addr (*)(void))ptr)();
747 return ((void *)target);
751 _rtld_bind(Obj_Entry *obj, Elf_Size reloff, void *stack)
755 const Obj_Entry *defobj;
758 RtldLockState lockstate;
760 rlock_acquire(rtld_bind_lock, &lockstate);
761 if (sigsetjmp(lockstate.env, 0) != 0)
762 lock_upgrade(rtld_bind_lock, &lockstate);
764 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
766 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
768 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
769 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
773 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
774 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
776 target = (Elf_Addr)(defobj->relocbase + def->st_value);
778 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
779 defobj->strtab + def->st_name, basename(obj->path),
780 (void *)target, basename(defobj->path));
783 * If we have a function call tracing hook, and the
784 * hook would like to keep tracing this one function,
785 * prevent the relocation so we will wind up here
786 * the next time again.
788 * We don't want to functrace calls from the functracer
789 * to avoid recursive loops.
791 if (rtld_functrace != NULL && obj != rtld_functrace_obj) {
792 if (rtld_functrace(obj->path,
794 defobj->strtab + def->st_name,
796 lock_release(rtld_bind_lock, &lockstate);
801 * Write the new contents for the jmpslot. Note that depending on
802 * architecture, the value which we need to return back to the
803 * lazy binding trampoline may or may not be the target
804 * address. The value returned from reloc_jmpslot() is the value
805 * that the trampoline needs.
807 target = reloc_jmpslot(where, target, defobj, obj, rel);
808 lock_release(rtld_bind_lock, &lockstate);
813 * Error reporting function. Use it like printf. If formats the message
814 * into a buffer, and sets things up so that the next call to dlerror()
815 * will return the message.
818 _rtld_error(const char *fmt, ...)
820 static char buf[512];
824 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
830 * Return a dynamically-allocated copy of the current error message, if any.
835 return error_message == NULL ? NULL : xstrdup(error_message);
839 * Restore the current error message from a copy which was previously saved
840 * by errmsg_save(). The copy is freed.
843 errmsg_restore(char *saved_msg)
845 if (saved_msg == NULL)
846 error_message = NULL;
848 _rtld_error("%s", saved_msg);
854 basename(const char *name)
856 const char *p = strrchr(name, '/');
857 return p != NULL ? p + 1 : name;
860 static struct utsname uts;
863 origin_subst_one(char **res, const char *real, const char *kw, const char *subst,
873 subst_len = kw_len = 0;
877 if (subst_len == 0) {
878 subst_len = strlen(subst);
882 *res = xmalloc(PATH_MAX);
885 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) {
886 _rtld_error("Substitution of %s in %s cannot be performed",
888 if (may_free != NULL)
893 memcpy(res1, p, p1 - p);
895 memcpy(res1, subst, subst_len);
900 if (may_free != NULL)
903 *res = xstrdup(real);
907 if (may_free != NULL)
909 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) {
919 origin_subst(const char *real, const char *origin_path)
921 char *res1, *res2, *res3, *res4;
923 if (uts.sysname[0] == '\0') {
924 if (uname(&uts) != 0) {
925 _rtld_error("utsname failed: %d", errno);
929 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) ||
930 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) ||
931 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) ||
932 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3))
940 const char *msg = dlerror();
944 rtld_fdputstr(STDERR_FILENO, msg);
945 rtld_fdputchar(STDERR_FILENO, '\n');
950 * Process a shared object's DYNAMIC section, and save the important
951 * information in its Obj_Entry structure.
954 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
955 const Elf_Dyn **dyn_soname)
958 Needed_Entry **needed_tail = &obj->needed;
959 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
960 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
961 int plttype = DT_REL;
966 obj->bind_now = false;
967 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
968 switch (dynp->d_tag) {
971 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
975 obj->relsize = dynp->d_un.d_val;
979 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
983 obj->pltrel = (const Elf_Rel *)
984 (obj->relocbase + dynp->d_un.d_ptr);
988 obj->pltrelsize = dynp->d_un.d_val;
992 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
996 obj->relasize = dynp->d_un.d_val;
1000 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1004 plttype = dynp->d_un.d_val;
1005 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1009 obj->symtab = (const Elf_Sym *)
1010 (obj->relocbase + dynp->d_un.d_ptr);
1014 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1018 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
1022 obj->strsize = dynp->d_un.d_val;
1026 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
1031 obj->verneednum = dynp->d_un.d_val;
1035 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
1040 obj->verdefnum = dynp->d_un.d_val;
1044 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1050 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
1051 (obj->relocbase + dynp->d_un.d_ptr);
1052 obj->nbuckets = hashtab[0];
1053 obj->nchains = hashtab[1];
1054 obj->buckets = hashtab + 2;
1055 obj->chains = obj->buckets + obj->nbuckets;
1056 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1057 obj->buckets != NULL;
1063 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
1064 (obj->relocbase + dynp->d_un.d_ptr);
1065 obj->nbuckets_gnu = hashtab[0];
1066 obj->symndx_gnu = hashtab[1];
1067 const Elf32_Word nmaskwords = hashtab[2];
1068 const int bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1069 /* Number of bitmask words is required to be power of 2 */
1070 const bool nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0);
1071 obj->maskwords_bm_gnu = nmaskwords - 1;
1072 obj->shift2_gnu = hashtab[3];
1073 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
1074 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1075 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1077 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 &&
1078 obj->buckets_gnu != NULL;
1084 Needed_Entry *nep = NEW(Needed_Entry);
1085 nep->name = dynp->d_un.d_val;
1090 needed_tail = &nep->next;
1096 Needed_Entry *nep = NEW(Needed_Entry);
1097 nep->name = dynp->d_un.d_val;
1101 *needed_filtees_tail = nep;
1102 needed_filtees_tail = &nep->next;
1108 Needed_Entry *nep = NEW(Needed_Entry);
1109 nep->name = dynp->d_un.d_val;
1113 *needed_aux_filtees_tail = nep;
1114 needed_aux_filtees_tail = &nep->next;
1119 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1123 obj->textrel = true;
1127 obj->symbolic = true;
1131 case DT_RUNPATH: /* XXX: process separately */
1133 * We have to wait until later to process this, because we
1134 * might not have gotten the address of the string table yet.
1144 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1148 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1151 case DT_PREINIT_ARRAY:
1152 obj->preinit_array = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1156 obj->init_array = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1160 obj->fini_array = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1163 case DT_PREINIT_ARRAYSZ:
1164 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1167 case DT_INIT_ARRAYSZ:
1168 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1171 case DT_FINI_ARRAYSZ:
1172 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1176 /* XXX - not implemented yet */
1178 dbg("Filling in DT_DEBUG entry");
1179 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1183 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1184 obj->z_origin = true;
1185 if (dynp->d_un.d_val & DF_SYMBOLIC)
1186 obj->symbolic = true;
1187 if (dynp->d_un.d_val & DF_TEXTREL)
1188 obj->textrel = true;
1189 if (dynp->d_un.d_val & DF_BIND_NOW)
1190 obj->bind_now = true;
1191 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1196 if (dynp->d_un.d_val & DF_1_NOOPEN)
1197 obj->z_noopen = true;
1198 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1199 obj->z_origin = true;
1200 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1202 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1203 obj->bind_now = true;
1204 if (dynp->d_un.d_val & DF_1_NODELETE)
1205 obj->z_nodelete = true;
1206 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1207 obj->z_loadfltr = true;
1212 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1219 obj->traced = false;
1221 if (plttype == DT_RELA) {
1222 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1224 obj->pltrelasize = obj->pltrelsize;
1225 obj->pltrelsize = 0;
1228 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1229 if (obj->valid_hash_sysv)
1230 obj->dynsymcount = obj->nchains;
1231 else if (obj->valid_hash_gnu) {
1232 obj->dynsymcount = 0;
1233 for (Elf32_Word bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1234 if (obj->buckets_gnu[bkt] == 0)
1236 const Elf32_Word *hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1239 while ((*hashval++ & 1u) == 0);
1241 obj->dynsymcount += obj->symndx_gnu;
1246 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1247 const Elf_Dyn *dyn_soname)
1250 if (obj->z_origin && obj->origin_path == NULL) {
1251 obj->origin_path = xmalloc(PATH_MAX);
1252 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1256 if (dyn_rpath != NULL) {
1257 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1259 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1262 if (dyn_soname != NULL)
1263 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1267 digest_dynamic(Obj_Entry *obj, int early)
1269 const Elf_Dyn *dyn_rpath;
1270 const Elf_Dyn *dyn_soname;
1272 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname);
1273 digest_dynamic2(obj, dyn_rpath, dyn_soname);
1277 * Process a shared object's program header. This is used only for the
1278 * main program, when the kernel has already loaded the main program
1279 * into memory before calling the dynamic linker. It creates and
1280 * returns an Obj_Entry structure.
1283 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1286 const Elf_Phdr *phlimit = phdr + phnum;
1288 Elf_Addr note_start, note_end;
1292 for (ph = phdr; ph < phlimit; ph++) {
1293 if (ph->p_type != PT_PHDR)
1297 obj->phsize = ph->p_memsz;
1298 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1302 obj->stack_flags = PF_X | PF_R | PF_W;
1304 for (ph = phdr; ph < phlimit; ph++) {
1305 switch (ph->p_type) {
1308 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1312 if (nsegs == 0) { /* First load segment */
1313 obj->vaddrbase = trunc_page(ph->p_vaddr);
1314 obj->mapbase = obj->vaddrbase + obj->relocbase;
1315 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1317 } else { /* Last load segment */
1318 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1325 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1330 obj->tlssize = ph->p_memsz;
1331 obj->tlsalign = ph->p_align;
1332 obj->tlsinitsize = ph->p_filesz;
1333 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1337 obj->stack_flags = ph->p_flags;
1341 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1342 obj->relro_size = round_page(ph->p_memsz);
1346 obj->note_present = true;
1347 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1348 note_end = note_start + ph->p_filesz;
1349 digest_notes(obj, note_start, note_end);
1354 _rtld_error("%s: too few PT_LOAD segments", path);
1363 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1365 const Elf_Note *note;
1366 const char *note_name;
1369 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1370 note = (const Elf_Note *)((const char *)(note + 1) +
1371 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1372 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1373 if (note->n_namesz != sizeof(NOTE_VENDOR) ||
1374 note->n_descsz != sizeof(int32_t))
1376 if (note->n_type != ABI_NOTETYPE && note->n_type != CRT_NOINIT_NOTETYPE)
1378 note_name = (const char *)(note + 1);
1379 if (strncmp(NOTE_VENDOR, note_name, sizeof(NOTE_VENDOR)) != 0)
1381 switch (note->n_type) {
1383 /* DragonFly osrel note */
1384 p = (uintptr_t)(note + 1);
1385 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1386 obj->osrel = *(const int32_t *)(p);
1387 dbg("note osrel %d", obj->osrel);
1389 case CRT_NOINIT_NOTETYPE:
1390 /* DragonFly 'crt does not call init' note */
1391 obj->crt_no_init = true;
1392 dbg("note crt_no_init");
1399 dlcheck(void *handle)
1403 for (obj = obj_list; obj != NULL; obj = obj->next)
1404 if (obj == (Obj_Entry *) handle)
1407 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1408 _rtld_error("Invalid shared object handle %p", handle);
1415 * If the given object is already in the donelist, return true. Otherwise
1416 * add the object to the list and return false.
1419 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1423 for (i = 0; i < dlp->num_used; i++)
1424 if (dlp->objs[i] == obj)
1427 * Our donelist allocation should always be sufficient. But if
1428 * our threads locking isn't working properly, more shared objects
1429 * could have been loaded since we allocated the list. That should
1430 * never happen, but we'll handle it properly just in case it does.
1432 if (dlp->num_used < dlp->num_alloc)
1433 dlp->objs[dlp->num_used++] = obj;
1438 * Hash function for symbol table lookup. Don't even think about changing
1439 * this. It is specified by the System V ABI.
1442 elf_hash(const char *name)
1444 const unsigned char *p = (const unsigned char *) name;
1445 unsigned long h = 0;
1448 while (*p != '\0') {
1449 h = (h << 4) + *p++;
1450 if ((g = h & 0xf0000000) != 0)
1458 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1459 * unsigned in case it's implemented with a wider type.
1461 static uint_fast32_t
1462 gnu_hash (const char *s)
1464 uint_fast32_t h = 5381;
1465 for (unsigned char c = *s; c != '\0'; c = *++s)
1467 return h & 0xffffffff;
1471 * Find the library with the given name, and return its full pathname.
1472 * The returned string is dynamically allocated. Generates an error
1473 * message and returns NULL if the library cannot be found.
1475 * If the second argument is non-NULL, then it refers to an already-
1476 * loaded shared object, whose library search path will be searched.
1478 * The search order is:
1480 * rpath in the referencing file
1485 find_library(const char *xname, const Obj_Entry *refobj)
1490 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1491 if (xname[0] != '/' && !trust) {
1492 _rtld_error("Absolute pathname required for shared object \"%s\"",
1496 if (refobj != NULL && refobj->z_origin)
1497 return origin_subst(xname, refobj->origin_path);
1499 return xstrdup(xname);
1502 if (libmap_disable || (refobj == NULL) ||
1503 (name = lm_find(refobj->path, xname)) == NULL)
1504 name = (char *)xname;
1506 dbg(" Searching for \"%s\"", name);
1508 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1510 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1511 (pathname = search_library_path(name, gethints())) != NULL ||
1512 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1515 if(refobj != NULL && refobj->path != NULL) {
1516 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1517 name, basename(refobj->path));
1519 _rtld_error("Shared object \"%s\" not found", name);
1525 * Given a symbol number in a referencing object, find the corresponding
1526 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1527 * no definition was found. Returns a pointer to the Obj_Entry of the
1528 * defining object via the reference parameter DEFOBJ_OUT.
1531 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1532 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1533 RtldLockState *lockstate)
1537 const Obj_Entry *defobj;
1543 * If we have already found this symbol, get the information from
1546 if (symnum >= refobj->dynsymcount)
1547 return NULL; /* Bad object */
1548 if (cache != NULL && cache[symnum].sym != NULL) {
1549 *defobj_out = cache[symnum].obj;
1550 return cache[symnum].sym;
1553 ref = refobj->symtab + symnum;
1554 name = refobj->strtab + ref->st_name;
1559 * We don't have to do a full scale lookup if the symbol is local.
1560 * We know it will bind to the instance in this load module; to
1561 * which we already have a pointer (ie ref). By not doing a lookup,
1562 * we not only improve performance, but it also avoids unresolvable
1563 * symbols when local symbols are not in the hash table.
1565 * This might occur for TLS module relocations, which simply use
1568 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1569 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1570 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1573 symlook_init(&req, name);
1575 req.ventry = fetch_ventry(refobj, symnum);
1576 req.lockstate = lockstate;
1577 res = symlook_default(&req, refobj);
1580 defobj = req.defobj_out;
1588 * If we found no definition and the reference is weak, treat the
1589 * symbol as having the value zero.
1591 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1597 *defobj_out = defobj;
1598 /* Record the information in the cache to avoid subsequent lookups. */
1599 if (cache != NULL) {
1600 cache[symnum].sym = def;
1601 cache[symnum].obj = defobj;
1604 if (refobj != &obj_rtld)
1605 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1611 * Return the search path from the ldconfig hints file, reading it if
1612 * necessary. Returns NULL if there are problems with the hints file,
1613 * or if the search path there is empty.
1620 if (hints == NULL) {
1622 struct elfhints_hdr hdr;
1625 /* Keep from trying again in case the hints file is bad. */
1628 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1)
1630 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1631 hdr.magic != ELFHINTS_MAGIC ||
1636 p = xmalloc(hdr.dirlistlen + 1);
1637 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1638 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) {
1646 return hints[0] != '\0' ? hints : NULL;
1650 init_dag(Obj_Entry *root)
1652 const Needed_Entry *needed;
1653 const Objlist_Entry *elm;
1656 if (root->dag_inited)
1658 donelist_init(&donelist);
1660 /* Root object belongs to own DAG. */
1661 objlist_push_tail(&root->dldags, root);
1662 objlist_push_tail(&root->dagmembers, root);
1663 donelist_check(&donelist, root);
1666 * Add dependencies of root object to DAG in breadth order
1667 * by exploiting the fact that each new object get added
1668 * to the tail of the dagmembers list.
1670 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1671 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1672 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1674 objlist_push_tail(&needed->obj->dldags, root);
1675 objlist_push_tail(&root->dagmembers, needed->obj);
1678 root->dag_inited = true;
1682 * Initialize the dynamic linker. The argument is the address at which
1683 * the dynamic linker has been mapped into memory. The primary task of
1684 * this function is to relocate the dynamic linker.
1687 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1689 Obj_Entry objtmp; /* Temporary rtld object */
1690 const Elf_Dyn *dyn_rpath;
1691 const Elf_Dyn *dyn_soname;
1694 * Conjure up an Obj_Entry structure for the dynamic linker.
1696 * The "path" member can't be initialized yet because string constants
1697 * cannot yet be accessed. Below we will set it correctly.
1699 memset(&objtmp, 0, sizeof(objtmp));
1702 objtmp.mapbase = mapbase;
1704 objtmp.relocbase = mapbase;
1706 if (RTLD_IS_DYNAMIC()) {
1707 objtmp.dynamic = rtld_dynamic(&objtmp);
1708 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname);
1709 assert(objtmp.needed == NULL);
1710 assert(!objtmp.textrel);
1713 * Temporarily put the dynamic linker entry into the object list, so
1714 * that symbols can be found.
1717 relocate_objects(&objtmp, true, &objtmp, NULL);
1720 /* Initialize the object list. */
1721 obj_tail = &obj_list;
1723 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1724 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1726 #ifdef ENABLE_OSRELDATE
1727 if (aux_info[AT_OSRELDATE] != NULL)
1728 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1731 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname);
1733 /* Replace the path with a dynamically allocated copy. */
1734 obj_rtld.path = xstrdup(PATH_RTLD);
1736 r_debug.r_brk = r_debug_state;
1737 r_debug.r_state = RT_CONSISTENT;
1741 * Add the init functions from a needed object list (and its recursive
1742 * needed objects) to "list". This is not used directly; it is a helper
1743 * function for initlist_add_objects(). The write lock must be held
1744 * when this function is called.
1747 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1749 /* Recursively process the successor needed objects. */
1750 if (needed->next != NULL)
1751 initlist_add_neededs(needed->next, list);
1753 /* Process the current needed object. */
1754 if (needed->obj != NULL)
1755 initlist_add_objects(needed->obj, &needed->obj->next, list);
1759 * Scan all of the DAGs rooted in the range of objects from "obj" to
1760 * "tail" and add their init functions to "list". This recurses over
1761 * the DAGs and ensure the proper init ordering such that each object's
1762 * needed libraries are initialized before the object itself. At the
1763 * same time, this function adds the objects to the global finalization
1764 * list "list_fini" in the opposite order. The write lock must be
1765 * held when this function is called.
1768 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1770 if (obj->init_scanned || obj->init_done)
1772 obj->init_scanned = true;
1774 /* Recursively process the successor objects. */
1775 if (&obj->next != tail)
1776 initlist_add_objects(obj->next, tail, list);
1778 /* Recursively process the needed objects. */
1779 if (obj->needed != NULL)
1780 initlist_add_neededs(obj->needed, list);
1782 /* Add the object to the init list. */
1783 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1784 obj->init_array != (Elf_Addr)NULL)
1785 objlist_push_tail(list, obj);
1787 /* Add the object to the global fini list in the reverse order. */
1788 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1789 && !obj->on_fini_list) {
1790 objlist_push_head(&list_fini, obj);
1791 obj->on_fini_list = true;
1796 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1800 is_exported(const Elf_Sym *def)
1803 const func_ptr_type *p;
1805 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value);
1806 for (p = exports; *p != NULL; p++)
1807 if (FPTR_TARGET(*p) == value)
1813 free_needed_filtees(Needed_Entry *n)
1815 Needed_Entry *needed, *needed1;
1817 for (needed = n; needed != NULL; needed = needed->next) {
1818 if (needed->obj != NULL) {
1819 dlclose(needed->obj);
1823 for (needed = n; needed != NULL; needed = needed1) {
1824 needed1 = needed->next;
1830 unload_filtees(Obj_Entry *obj)
1833 free_needed_filtees(obj->needed_filtees);
1834 obj->needed_filtees = NULL;
1835 free_needed_filtees(obj->needed_aux_filtees);
1836 obj->needed_aux_filtees = NULL;
1837 obj->filtees_loaded = false;
1841 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags)
1844 for (; needed != NULL; needed = needed->next) {
1845 needed->obj = dlopen_object(obj->strtab + needed->name, obj,
1846 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
1852 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
1855 lock_restart_for_upgrade(lockstate);
1856 if (!obj->filtees_loaded) {
1857 load_filtee1(obj, obj->needed_filtees, flags);
1858 load_filtee1(obj, obj->needed_aux_filtees, flags);
1859 obj->filtees_loaded = true;
1864 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
1868 for (; needed != NULL; needed = needed->next) {
1869 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj,
1870 flags & ~RTLD_LO_NOLOAD);
1871 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
1873 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) {
1874 dbg("obj %s nodelete", obj1->path);
1877 obj1->ref_nodel = true;
1884 * Given a shared object, traverse its list of needed objects, and load
1885 * each of them. Returns 0 on success. Generates an error message and
1886 * returns -1 on failure.
1889 load_needed_objects(Obj_Entry *first, int flags)
1893 for (obj = first; obj != NULL; obj = obj->next) {
1894 if (process_needed(obj, obj->needed, flags) == -1)
1901 load_preload_objects(void)
1903 char *p = ld_preload;
1904 static const char delim[] = " \t:;";
1909 p += strspn(p, delim);
1910 while (*p != '\0') {
1911 size_t len = strcspn(p, delim);
1919 obj = load_object(p, NULL, 0);
1921 return -1; /* XXX - cleanup */
1924 p += strspn(p, delim);
1926 /* Check for the magic tracing function */
1927 symlook_init(&req, RTLD_FUNCTRACE);
1928 res = symlook_obj(&req, obj);
1930 rtld_functrace = (void *)(req.defobj_out->relocbase +
1931 req.sym_out->st_value);
1932 rtld_functrace_obj = req.defobj_out;
1935 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
1940 * Load a shared object into memory, if it is not already loaded.
1942 * Returns a pointer to the Obj_Entry for the object. Returns NULL
1946 load_object(const char *name, const Obj_Entry *refobj, int flags)
1953 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1954 if (object_match_name(obj, name))
1957 path = find_library(name, refobj);
1962 * If we didn't find a match by pathname, open the file and check
1963 * again by device and inode. This avoids false mismatches caused
1964 * by multiple links or ".." in pathnames.
1966 * To avoid a race, we open the file and use fstat() rather than
1969 if ((fd = open(path, O_RDONLY)) == -1) {
1970 _rtld_error("Cannot open \"%s\"", path);
1974 if (fstat(fd, &sb) == -1) {
1975 _rtld_error("Cannot fstat \"%s\"", path);
1980 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1981 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
1984 object_add_name(obj, name);
1989 if (flags & RTLD_LO_NOLOAD) {
1995 /* First use of this object, so we must map it in */
1996 obj = do_load_object(fd, name, path, &sb, flags);
2005 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2012 * but first, make sure that environment variables haven't been
2013 * used to circumvent the noexec flag on a filesystem.
2015 if (dangerous_ld_env) {
2016 if (fstatfs(fd, &fs) != 0) {
2017 _rtld_error("Cannot fstatfs \"%s\"", path);
2020 if (fs.f_flags & MNT_NOEXEC) {
2021 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2025 dbg("loading \"%s\"", path);
2026 obj = map_object(fd, path, sbp);
2030 object_add_name(obj, name);
2032 digest_dynamic(obj, 0);
2033 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2035 dbg("refusing to load non-loadable \"%s\"", obj->path);
2036 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2037 munmap(obj->mapbase, obj->mapsize);
2043 obj_tail = &obj->next;
2046 linkmap_add(obj); /* for GDB & dlinfo() */
2047 max_stack_flags |= obj->stack_flags;
2049 dbg(" %p .. %p: %s", obj->mapbase,
2050 obj->mapbase + obj->mapsize - 1, obj->path);
2052 dbg(" WARNING: %s has impure text", obj->path);
2053 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2060 obj_from_addr(const void *addr)
2064 for (obj = obj_list; obj != NULL; obj = obj->next) {
2065 if (addr < (void *) obj->mapbase)
2067 if (addr < (void *) (obj->mapbase + obj->mapsize))
2074 * Call the finalization functions for each of the objects in "list"
2075 * belonging to the DAG of "root" and referenced once. If NULL "root"
2076 * is specified, every finalization function will be called regardless
2077 * of the reference count and the list elements won't be freed. All of
2078 * the objects are expected to have non-NULL fini functions.
2081 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2085 Elf_Addr *fini_addr;
2088 assert(root == NULL || root->refcount == 1);
2091 * Preserve the current error message since a fini function might
2092 * call into the dynamic linker and overwrite it.
2094 saved_msg = errmsg_save();
2096 STAILQ_FOREACH(elm, list, link) {
2097 if (root != NULL && (elm->obj->refcount != 1 ||
2098 objlist_find(&root->dagmembers, elm->obj) == NULL))
2101 /* Remove object from fini list to prevent recursive invocation. */
2102 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2104 * XXX: If a dlopen() call references an object while the
2105 * fini function is in progress, we might end up trying to
2106 * unload the referenced object in dlclose() or the object
2107 * won't be unloaded although its fini function has been
2110 lock_release(rtld_bind_lock, lockstate);
2113 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. When this
2114 * happens, DT_FINI_ARRAY is processed first, and it is also processed
2115 * backwards. It is possible to encounter DT_FINI_ARRAY elements with
2116 * values of 0 or 1, but they need to be ignored.
2118 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2119 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2120 for (index = elm->obj->fini_array_num - 1; index >= 0; index--) {
2121 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2122 dbg("calling fini array function for %s at %p",
2123 elm->obj->path, (void *)fini_addr[index]);
2124 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2125 (void *)fini_addr[index], 0, 0, elm->obj->path);
2126 call_initfini_pointer(elm->obj, fini_addr[index]);
2130 if (elm->obj->fini != (Elf_Addr)NULL) {
2131 dbg("calling fini function for %s at %p", elm->obj->path,
2132 (void *)elm->obj->fini);
2133 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2134 0, 0, elm->obj->path);
2135 call_initfini_pointer(elm->obj, elm->obj->fini);
2137 wlock_acquire(rtld_bind_lock, lockstate);
2138 /* No need to free anything if process is going down. */
2142 * We must restart the list traversal after every fini call
2143 * because a dlclose() call from the fini function or from
2144 * another thread might have modified the reference counts.
2148 } while (elm != NULL);
2149 errmsg_restore(saved_msg);
2153 * If the main program is defined with a .preinit_array section, call
2154 * each function in order. This must occur before the initialization
2155 * of any shared object or the main program.
2158 preinitialize_main_object (void)
2160 Elf_Addr *preinit_addr;
2163 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2164 if (preinit_addr == NULL)
2167 for (index = 0; index < obj_main->preinit_array_num; index++) {
2168 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2169 dbg("calling preinit function for %s at %p", obj_main->path,
2170 (void *)preinit_addr[index]);
2171 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2172 0, 0, obj_main->path);
2173 call_init_pointer(obj_main, preinit_addr[index]);
2179 * Call the initialization functions for each of the objects in
2180 * "list". All of the objects are expected to have non-NULL init
2184 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2189 Elf_Addr *init_addr;
2193 * Clean init_scanned flag so that objects can be rechecked and
2194 * possibly initialized earlier if any of vectors called below
2195 * cause the change by using dlopen.
2197 for (obj = obj_list; obj != NULL; obj = obj->next)
2198 obj->init_scanned = false;
2201 * Preserve the current error message since an init function might
2202 * call into the dynamic linker and overwrite it.
2204 saved_msg = errmsg_save();
2205 STAILQ_FOREACH(elm, list, link) {
2206 if (elm->obj->init_done) /* Initialized early. */
2210 * Race: other thread might try to use this object before current
2211 * one completes the initilization. Not much can be done here
2212 * without better locking.
2214 elm->obj->init_done = true;
2215 lock_release(rtld_bind_lock, lockstate);
2218 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. When
2219 * this happens, DT_INIT is processed first. It is possible to
2220 * encounter DT_INIT_ARRAY elements with values of 0 or 1, but they
2221 * need to be ignored.
2223 if (elm->obj->init != (Elf_Addr)NULL) {
2224 dbg("calling init function for %s at %p", elm->obj->path,
2225 (void *)elm->obj->init);
2226 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2227 0, 0, elm->obj->path);
2228 call_initfini_pointer(elm->obj, elm->obj->init);
2230 init_addr = (Elf_Addr *)elm->obj->init_array;
2231 if (init_addr != NULL) {
2232 for (index = 0; index < elm->obj->init_array_num; index++) {
2233 if (init_addr[index] != 0 && init_addr[index] != 1) {
2234 dbg("calling init array function for %s at %p", elm->obj->path,
2235 (void *)init_addr[index]);
2236 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2237 (void *)init_addr[index], 0, 0, elm->obj->path);
2238 call_init_pointer(elm->obj, init_addr[index]);
2242 wlock_acquire(rtld_bind_lock, lockstate);
2244 errmsg_restore(saved_msg);
2248 objlist_clear(Objlist *list)
2252 while (!STAILQ_EMPTY(list)) {
2253 elm = STAILQ_FIRST(list);
2254 STAILQ_REMOVE_HEAD(list, link);
2259 static Objlist_Entry *
2260 objlist_find(Objlist *list, const Obj_Entry *obj)
2264 STAILQ_FOREACH(elm, list, link)
2265 if (elm->obj == obj)
2271 objlist_init(Objlist *list)
2277 objlist_push_head(Objlist *list, Obj_Entry *obj)
2281 elm = NEW(Objlist_Entry);
2283 STAILQ_INSERT_HEAD(list, elm, link);
2287 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2291 elm = NEW(Objlist_Entry);
2293 STAILQ_INSERT_TAIL(list, elm, link);
2297 objlist_remove(Objlist *list, Obj_Entry *obj)
2301 if ((elm = objlist_find(list, obj)) != NULL) {
2302 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2308 * Relocate newly-loaded shared objects. The argument is a pointer to
2309 * the Obj_Entry for the first such object. All objects from the first
2310 * to the end of the list of objects are relocated. Returns 0 on success,
2314 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2315 RtldLockState *lockstate)
2319 for (obj = first; obj != NULL; obj = obj->next) {
2321 dbg("relocating \"%s\"", obj->path);
2322 if (obj->symtab == NULL || obj->strtab == NULL ||
2323 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2324 _rtld_error("%s: Shared object has no run-time symbol table",
2330 /* There are relocations to the write-protected text segment. */
2331 if (mprotect(obj->mapbase, obj->textsize,
2332 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2333 _rtld_error("%s: Cannot write-enable text segment: %s",
2334 obj->path, rtld_strerror(errno));
2339 /* Process the non-PLT relocations. */
2340 if (reloc_non_plt(obj, rtldobj, lockstate))
2344 * Reprotect the text segment. Make sure it is included in the
2345 * core dump since we modified it. This unfortunately causes the
2346 * entire text segment to core-out but we don't have much of a
2347 * choice. We could try to only reenable core dumps on pages
2348 * in which relocations occured but that is likely most of the text
2349 * pages anyway, and even that would not work because the rest of
2350 * the text pages would wind up as a read-only OBJT_DEFAULT object
2351 * (created due to our modifications) backed by the original OBJT_VNODE
2352 * object, and the ELF coredump code is currently only able to dump
2353 * vnode records for pure vnode-backed mappings, not vnode backings
2354 * to memory objects.
2357 madvise(obj->mapbase, obj->textsize, MADV_CORE);
2358 if (mprotect(obj->mapbase, obj->textsize,
2359 PROT_READ|PROT_EXEC) == -1) {
2360 _rtld_error("%s: Cannot write-protect text segment: %s",
2361 obj->path, rtld_strerror(errno));
2367 /* Set the special PLT or GOT entries. */
2370 /* Process the PLT relocations. */
2371 if (reloc_plt(obj) == -1)
2373 /* Relocate the jump slots if we are doing immediate binding. */
2374 if (obj->bind_now || bind_now)
2375 if (reloc_jmpslots(obj, lockstate) == -1)
2379 * Set up the magic number and version in the Obj_Entry. These
2380 * were checked in the crt1.o from the original ElfKit, so we
2381 * set them for backward compatibility.
2383 obj->magic = RTLD_MAGIC;
2384 obj->version = RTLD_VERSION;
2387 * Set relocated data to read-only status if protection specified
2390 if (obj->relro_size) {
2391 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) {
2392 _rtld_error("%s: Cannot enforce relro relocation: %s",
2393 obj->path, rtld_strerror(errno));
2403 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2404 * referencing STT_GNU_IFUNC symbols is postponed till the other
2405 * relocations are done. The indirect functions specified as
2406 * ifunc are allowed to call other symbols, so we need to have
2407 * objects relocated before asking for resolution from indirects.
2409 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2410 * instead of the usual lazy handling of PLT slots. It is
2411 * consistent with how GNU does it.
2414 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, RtldLockState *lockstate)
2416 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2418 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2419 reloc_gnu_ifunc(obj, lockstate) == -1)
2425 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, RtldLockState *lockstate)
2429 for (obj = first; obj != NULL; obj = obj->next) {
2430 if (resolve_object_ifunc(obj, bind_now, lockstate) == -1)
2437 initlist_objects_ifunc(Objlist *list, bool bind_now, RtldLockState *lockstate)
2441 STAILQ_FOREACH(elm, list, link) {
2442 if (resolve_object_ifunc(elm->obj, bind_now, lockstate) == -1)
2449 * Cleanup procedure. It will be called (by the atexit mechanism) just
2450 * before the process exits.
2455 RtldLockState lockstate;
2457 wlock_acquire(rtld_bind_lock, &lockstate);
2459 objlist_call_fini(&list_fini, NULL, &lockstate);
2460 /* No need to remove the items from the list, since we are exiting. */
2461 if (!libmap_disable)
2463 lock_release(rtld_bind_lock, &lockstate);
2467 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2472 path += strspn(path, ":;");
2473 while (*path != '\0') {
2477 len = strcspn(path, ":;");
2478 res = callback(path, len, arg);
2484 path += strspn(path, ":;");
2490 struct try_library_args {
2498 try_library_path(const char *dir, size_t dirlen, void *param)
2500 struct try_library_args *arg;
2503 if (*dir == '/' || trust) {
2506 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2509 pathname = arg->buffer;
2510 strncpy(pathname, dir, dirlen);
2511 pathname[dirlen] = '/';
2512 strcpy(pathname + dirlen + 1, arg->name);
2514 dbg(" Trying \"%s\"", pathname);
2515 if (access(pathname, F_OK) == 0) { /* We found it */
2516 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2517 strcpy(pathname, arg->buffer);
2525 search_library_path(const char *name, const char *path)
2528 struct try_library_args arg;
2534 arg.namelen = strlen(name);
2535 arg.buffer = xmalloc(PATH_MAX);
2536 arg.buflen = PATH_MAX;
2538 p = path_enumerate(path, try_library_path, &arg);
2546 dlclose(void *handle)
2549 RtldLockState lockstate;
2551 wlock_acquire(rtld_bind_lock, &lockstate);
2552 root = dlcheck(handle);
2554 lock_release(rtld_bind_lock, &lockstate);
2557 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2560 /* Unreference the object and its dependencies. */
2561 root->dl_refcount--;
2563 if (root->refcount == 1) {
2565 * The object will be no longer referenced, so we must unload it.
2566 * First, call the fini functions.
2568 objlist_call_fini(&list_fini, root, &lockstate);
2572 /* Finish cleaning up the newly-unreferenced objects. */
2573 GDB_STATE(RT_DELETE,&root->linkmap);
2574 unload_object(root);
2575 GDB_STATE(RT_CONSISTENT,NULL);
2579 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2580 lock_release(rtld_bind_lock, &lockstate);
2587 char *msg = error_message;
2588 error_message = NULL;
2593 dlopen(const char *name, int mode)
2595 RtldLockState lockstate;
2598 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2599 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2600 if (ld_tracing != NULL) {
2601 rlock_acquire(rtld_bind_lock, &lockstate);
2602 if (sigsetjmp(lockstate.env, 0) != 0)
2603 lock_upgrade(rtld_bind_lock, &lockstate);
2604 environ = (char **)*get_program_var_addr("environ", &lockstate);
2605 lock_release(rtld_bind_lock, &lockstate);
2607 lo_flags = RTLD_LO_DLOPEN;
2608 if (mode & RTLD_NODELETE)
2609 lo_flags |= RTLD_LO_NODELETE;
2610 if (mode & RTLD_NOLOAD)
2611 lo_flags |= RTLD_LO_NOLOAD;
2612 if (ld_tracing != NULL)
2613 lo_flags |= RTLD_LO_TRACE;
2615 return (dlopen_object(name, obj_main, lo_flags,
2616 mode & (RTLD_MODEMASK | RTLD_GLOBAL)));
2620 dlopen_cleanup(Obj_Entry *obj)
2625 if (obj->refcount == 0)
2630 dlopen_object(const char *name, Obj_Entry *refobj, int lo_flags, int mode)
2632 Obj_Entry **old_obj_tail;
2635 RtldLockState lockstate;
2638 objlist_init(&initlist);
2640 wlock_acquire(rtld_bind_lock, &lockstate);
2641 GDB_STATE(RT_ADD,NULL);
2643 old_obj_tail = obj_tail;
2649 obj = load_object(name, refobj, lo_flags);
2654 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2655 objlist_push_tail(&list_global, obj);
2656 if (*old_obj_tail != NULL) { /* We loaded something new. */
2657 assert(*old_obj_tail == obj);
2658 result = load_needed_objects(obj, lo_flags & RTLD_LO_DLOPEN);
2662 result = rtld_verify_versions(&obj->dagmembers);
2663 if (result != -1 && ld_tracing)
2665 if (result == -1 || (relocate_objects(obj, (mode & RTLD_MODEMASK)
2666 == RTLD_NOW, &obj_rtld, &lockstate)) == -1) {
2667 dlopen_cleanup(obj);
2670 /* Make list of init functions to call. */
2671 initlist_add_objects(obj, &obj->next, &initlist);
2676 * Bump the reference counts for objects on this DAG. If
2677 * this is the first dlopen() call for the object that was
2678 * already loaded as a dependency, initialize the dag
2684 if ((lo_flags & RTLD_LO_TRACE) != 0)
2687 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2688 obj->z_nodelete) && !obj->ref_nodel) {
2689 dbg("obj %s nodelete", obj->path);
2691 obj->z_nodelete = obj->ref_nodel = true;
2695 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2697 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2699 map_stacks_exec(&lockstate);
2701 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
2702 &lockstate) == -1) {
2703 objlist_clear(&initlist);
2704 dlopen_cleanup(obj);
2705 lock_release(rtld_bind_lock, &lockstate);
2709 /* Call the init functions. */
2710 objlist_call_init(&initlist, &lockstate);
2711 objlist_clear(&initlist);
2712 lock_release(rtld_bind_lock, &lockstate);
2715 trace_loaded_objects(obj);
2716 lock_release(rtld_bind_lock, &lockstate);
2721 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
2725 const Obj_Entry *obj, *defobj;
2728 RtldLockState lockstate;
2733 symlook_init(&req, name);
2735 req.flags = flags | SYMLOOK_IN_PLT;
2736 req.lockstate = &lockstate;
2738 rlock_acquire(rtld_bind_lock, &lockstate);
2739 if (sigsetjmp(lockstate.env, 0) != 0)
2740 lock_upgrade(rtld_bind_lock, &lockstate);
2741 if (handle == NULL || handle == RTLD_NEXT ||
2742 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
2744 if ((obj = obj_from_addr(retaddr)) == NULL) {
2745 _rtld_error("Cannot determine caller's shared object");
2746 lock_release(rtld_bind_lock, &lockstate);
2749 if (handle == NULL) { /* Just the caller's shared object. */
2750 res = symlook_obj(&req, obj);
2753 defobj = req.defobj_out;
2755 } else if (handle == RTLD_NEXT || /* Objects after caller's */
2756 handle == RTLD_SELF) { /* ... caller included */
2757 if (handle == RTLD_NEXT)
2759 for (; obj != NULL; obj = obj->next) {
2760 res = symlook_obj(&req, obj);
2763 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
2765 defobj = req.defobj_out;
2766 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
2772 * Search the dynamic linker itself, and possibly resolve the
2773 * symbol from there. This is how the application links to
2774 * dynamic linker services such as dlopen.
2776 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2777 res = symlook_obj(&req, &obj_rtld);
2778 if (res == 0 && is_exported(req.sym_out)) {
2780 defobj = req.defobj_out;
2784 assert(handle == RTLD_DEFAULT);
2785 res = symlook_default(&req, obj);
2787 defobj = req.defobj_out;
2792 if ((obj = dlcheck(handle)) == NULL) {
2793 lock_release(rtld_bind_lock, &lockstate);
2797 donelist_init(&donelist);
2798 if (obj->mainprog) {
2799 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
2800 res = symlook_global(&req, &donelist);
2803 defobj = req.defobj_out;
2806 * Search the dynamic linker itself, and possibly resolve the
2807 * symbol from there. This is how the application links to
2808 * dynamic linker services such as dlopen.
2810 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2811 res = symlook_obj(&req, &obj_rtld);
2814 defobj = req.defobj_out;
2819 /* Search the whole DAG rooted at the given object. */
2820 res = symlook_list(&req, &obj->dagmembers, &donelist);
2823 defobj = req.defobj_out;
2829 lock_release(rtld_bind_lock, &lockstate);
2832 * The value required by the caller is derived from the value
2833 * of the symbol. For the ia64 architecture, we need to
2834 * construct a function descriptor which the caller can use to
2835 * call the function with the right 'gp' value. For other
2836 * architectures and for non-functions, the value is simply
2837 * the relocated value of the symbol.
2839 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
2840 return (make_function_pointer(def, defobj));
2841 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
2842 return (rtld_resolve_ifunc(defobj, def));
2843 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
2845 ti.ti_module = defobj->tlsindex;
2846 ti.ti_offset = def->st_value;
2847 return (__tls_get_addr(&ti));
2849 return (defobj->relocbase + def->st_value);
2852 _rtld_error("Undefined symbol \"%s\"", name);
2853 lock_release(rtld_bind_lock, &lockstate);
2858 dlsym(void *handle, const char *name)
2860 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
2865 dlfunc(void *handle, const char *name)
2872 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
2878 dlvsym(void *handle, const char *name, const char *version)
2882 ventry.name = version;
2884 ventry.hash = elf_hash(version);
2886 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
2891 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
2893 const Obj_Entry *obj;
2894 RtldLockState lockstate;
2896 rlock_acquire(rtld_bind_lock, &lockstate);
2897 obj = obj_from_addr(addr);
2899 _rtld_error("No shared object contains address");
2900 lock_release(rtld_bind_lock, &lockstate);
2903 rtld_fill_dl_phdr_info(obj, phdr_info);
2904 lock_release(rtld_bind_lock, &lockstate);
2909 dladdr(const void *addr, Dl_info *info)
2911 const Obj_Entry *obj;
2914 unsigned long symoffset;
2915 RtldLockState lockstate;
2917 rlock_acquire(rtld_bind_lock, &lockstate);
2918 obj = obj_from_addr(addr);
2920 _rtld_error("No shared object contains address");
2921 lock_release(rtld_bind_lock, &lockstate);
2924 info->dli_fname = obj->path;
2925 info->dli_fbase = obj->mapbase;
2926 info->dli_saddr = NULL;
2927 info->dli_sname = NULL;
2930 * Walk the symbol list looking for the symbol whose address is
2931 * closest to the address sent in.
2933 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
2934 def = obj->symtab + symoffset;
2937 * For skip the symbol if st_shndx is either SHN_UNDEF or
2940 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
2944 * If the symbol is greater than the specified address, or if it
2945 * is further away from addr than the current nearest symbol,
2948 symbol_addr = obj->relocbase + def->st_value;
2949 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
2952 /* Update our idea of the nearest symbol. */
2953 info->dli_sname = obj->strtab + def->st_name;
2954 info->dli_saddr = symbol_addr;
2957 if (info->dli_saddr == addr)
2960 lock_release(rtld_bind_lock, &lockstate);
2965 dlinfo(void *handle, int request, void *p)
2967 const Obj_Entry *obj;
2968 RtldLockState lockstate;
2971 rlock_acquire(rtld_bind_lock, &lockstate);
2973 if (handle == NULL || handle == RTLD_SELF) {
2976 retaddr = __builtin_return_address(0); /* __GNUC__ only */
2977 if ((obj = obj_from_addr(retaddr)) == NULL)
2978 _rtld_error("Cannot determine caller's shared object");
2980 obj = dlcheck(handle);
2983 lock_release(rtld_bind_lock, &lockstate);
2989 case RTLD_DI_LINKMAP:
2990 *((struct link_map const **)p) = &obj->linkmap;
2992 case RTLD_DI_ORIGIN:
2993 error = rtld_dirname(obj->path, p);
2996 case RTLD_DI_SERINFOSIZE:
2997 case RTLD_DI_SERINFO:
2998 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3002 _rtld_error("Invalid request %d passed to dlinfo()", request);
3006 lock_release(rtld_bind_lock, &lockstate);
3012 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3015 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3016 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
3017 STAILQ_FIRST(&obj->names)->name : obj->path;
3018 phdr_info->dlpi_phdr = obj->phdr;
3019 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3020 phdr_info->dlpi_tls_modid = obj->tlsindex;
3021 phdr_info->dlpi_tls_data = obj->tlsinit;
3022 phdr_info->dlpi_adds = obj_loads;
3023 phdr_info->dlpi_subs = obj_loads - obj_count;
3027 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3029 struct dl_phdr_info phdr_info;
3030 const Obj_Entry *obj;
3031 RtldLockState bind_lockstate, phdr_lockstate;
3034 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3035 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3039 for (obj = obj_list; obj != NULL; obj = obj->next) {
3040 rtld_fill_dl_phdr_info(obj, &phdr_info);
3041 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3045 lock_release(rtld_bind_lock, &bind_lockstate);
3046 lock_release(rtld_phdr_lock, &phdr_lockstate);
3051 struct fill_search_info_args {
3054 Dl_serinfo *serinfo;
3055 Dl_serpath *serpath;
3060 fill_search_info(const char *dir, size_t dirlen, void *param)
3062 struct fill_search_info_args *arg;
3066 if (arg->request == RTLD_DI_SERINFOSIZE) {
3067 arg->serinfo->dls_cnt ++;
3068 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1;
3070 struct dl_serpath *s_entry;
3072 s_entry = arg->serpath;
3073 s_entry->dls_name = arg->strspace;
3074 s_entry->dls_flags = arg->flags;
3076 strncpy(arg->strspace, dir, dirlen);
3077 arg->strspace[dirlen] = '\0';
3079 arg->strspace += dirlen + 1;
3087 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3089 struct dl_serinfo _info;
3090 struct fill_search_info_args args;
3092 args.request = RTLD_DI_SERINFOSIZE;
3093 args.serinfo = &_info;
3095 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3098 path_enumerate(ld_library_path, fill_search_info, &args);
3099 path_enumerate(obj->rpath, fill_search_info, &args);
3100 path_enumerate(gethints(), fill_search_info, &args);
3101 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3104 if (request == RTLD_DI_SERINFOSIZE) {
3105 info->dls_size = _info.dls_size;
3106 info->dls_cnt = _info.dls_cnt;
3110 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3111 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3115 args.request = RTLD_DI_SERINFO;
3116 args.serinfo = info;
3117 args.serpath = &info->dls_serpath[0];
3118 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3120 args.flags = LA_SER_LIBPATH;
3121 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3124 args.flags = LA_SER_RUNPATH;
3125 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3128 args.flags = LA_SER_CONFIG;
3129 if (path_enumerate(gethints(), fill_search_info, &args) != NULL)
3132 args.flags = LA_SER_DEFAULT;
3133 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3139 rtld_dirname(const char *path, char *bname)
3143 /* Empty or NULL string gets treated as "." */
3144 if (path == NULL || *path == '\0') {
3150 /* Strip trailing slashes */
3151 endp = path + strlen(path) - 1;
3152 while (endp > path && *endp == '/')
3155 /* Find the start of the dir */
3156 while (endp > path && *endp != '/')
3159 /* Either the dir is "/" or there are no slashes */
3161 bname[0] = *endp == '/' ? '/' : '.';
3167 } while (endp > path && *endp == '/');
3170 if (endp - path + 2 > PATH_MAX)
3172 _rtld_error("Filename is too long: %s", path);
3176 strncpy(bname, path, endp - path + 1);
3177 bname[endp - path + 1] = '\0';
3182 rtld_dirname_abs(const char *path, char *base)
3184 char base_rel[PATH_MAX];
3186 if (rtld_dirname(path, base) == -1)
3190 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
3191 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
3192 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
3194 strcpy(base, base_rel);
3199 linkmap_add(Obj_Entry *obj)
3201 struct link_map *l = &obj->linkmap;
3202 struct link_map *prev;
3204 obj->linkmap.l_name = obj->path;
3205 obj->linkmap.l_addr = obj->mapbase;
3206 obj->linkmap.l_ld = obj->dynamic;
3208 /* GDB needs load offset on MIPS to use the symbols */
3209 obj->linkmap.l_offs = obj->relocbase;
3212 if (r_debug.r_map == NULL) {
3218 * Scan to the end of the list, but not past the entry for the
3219 * dynamic linker, which we want to keep at the very end.
3221 for (prev = r_debug.r_map;
3222 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3223 prev = prev->l_next)
3226 /* Link in the new entry. */
3228 l->l_next = prev->l_next;
3229 if (l->l_next != NULL)
3230 l->l_next->l_prev = l;
3235 linkmap_delete(Obj_Entry *obj)
3237 struct link_map *l = &obj->linkmap;
3239 if (l->l_prev == NULL) {
3240 if ((r_debug.r_map = l->l_next) != NULL)
3241 l->l_next->l_prev = NULL;
3245 if ((l->l_prev->l_next = l->l_next) != NULL)
3246 l->l_next->l_prev = l->l_prev;
3250 * Function for the debugger to set a breakpoint on to gain control.
3252 * The two parameters allow the debugger to easily find and determine
3253 * what the runtime loader is doing and to whom it is doing it.
3255 * When the loadhook trap is hit (r_debug_state, set at program
3256 * initialization), the arguments can be found on the stack:
3258 * +8 struct link_map *m
3259 * +4 struct r_debug *rd
3263 r_debug_state(struct r_debug* rd, struct link_map *m)
3266 * The following is a hack to force the compiler to emit calls to
3267 * this function, even when optimizing. If the function is empty,
3268 * the compiler is not obliged to emit any code for calls to it,
3269 * even when marked __noinline. However, gdb depends on those
3272 __asm __volatile("" : : : "memory");
3276 * Get address of the pointer variable in the main program.
3277 * Prefer non-weak symbol over the weak one.
3279 static const void **
3280 get_program_var_addr(const char *name, RtldLockState *lockstate)
3285 symlook_init(&req, name);
3286 req.lockstate = lockstate;
3287 donelist_init(&donelist);
3288 if (symlook_global(&req, &donelist) != 0)
3290 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3291 return ((const void **)make_function_pointer(req.sym_out,
3293 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3294 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3296 return ((const void **)(req.defobj_out->relocbase + req.sym_out->st_value));
3300 * Set a pointer variable in the main program to the given value. This
3301 * is used to set key variables such as "environ" before any of the
3302 * init functions are called.
3305 set_program_var(const char *name, const void *value)
3309 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3310 dbg("\"%s\": *%p <-- %p", name, addr, value);
3316 * Search the global objects, including dependencies and main object,
3317 * for the given symbol.
3320 symlook_global(SymLook *req, DoneList *donelist)
3323 const Objlist_Entry *elm;
3326 symlook_init_from_req(&req1, req);
3328 /* Search all objects loaded at program start up. */
3329 if (req->defobj_out == NULL ||
3330 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3331 res = symlook_list(&req1, &list_main, donelist);
3332 if (res == 0 && (req->defobj_out == NULL ||
3333 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3334 req->sym_out = req1.sym_out;
3335 req->defobj_out = req1.defobj_out;
3336 assert(req->defobj_out != NULL);
3340 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3341 STAILQ_FOREACH(elm, &list_global, link) {
3342 if (req->defobj_out != NULL &&
3343 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3345 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3346 if (res == 0 && (req->defobj_out == NULL ||
3347 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3348 req->sym_out = req1.sym_out;
3349 req->defobj_out = req1.defobj_out;
3350 assert(req->defobj_out != NULL);
3354 return (req->sym_out != NULL ? 0 : ESRCH);
3358 * This is a special version of getenv which is far more efficient
3359 * at finding LD_ environment vars.
3363 _getenv_ld(const char *id)
3367 int idlen = strlen(id);
3369 if (ld_index == LD_ARY_CACHE)
3371 if (ld_index == 0) {
3372 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) {
3373 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_')
3380 for (i = ld_index - 1; i >= 0; --i) {
3381 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=')
3382 return(ld_ary[i] + idlen + 1);
3388 * Given a symbol name in a referencing object, find the corresponding
3389 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3390 * no definition was found. Returns a pointer to the Obj_Entry of the
3391 * defining object via the reference parameter DEFOBJ_OUT.
3394 symlook_default(SymLook *req, const Obj_Entry *refobj)
3397 const Objlist_Entry *elm;
3401 donelist_init(&donelist);
3402 symlook_init_from_req(&req1, req);
3404 /* Look first in the referencing object if linked symbolically. */
3405 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3406 res = symlook_obj(&req1, refobj);
3408 req->sym_out = req1.sym_out;
3409 req->defobj_out = req1.defobj_out;
3410 assert(req->defobj_out != NULL);
3414 symlook_global(req, &donelist);
3416 /* Search all dlopened DAGs containing the referencing object. */
3417 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3418 if (req->sym_out != NULL &&
3419 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3421 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3422 if (res == 0 && (req->sym_out == NULL ||
3423 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3424 req->sym_out = req1.sym_out;
3425 req->defobj_out = req1.defobj_out;
3426 assert(req->defobj_out != NULL);
3431 * Search the dynamic linker itself, and possibly resolve the
3432 * symbol from there. This is how the application links to
3433 * dynamic linker services such as dlopen. Only the values listed
3434 * in the "exports" array can be resolved from the dynamic linker.
3436 if (req->sym_out == NULL ||
3437 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3438 res = symlook_obj(&req1, &obj_rtld);
3439 if (res == 0 && is_exported(req1.sym_out)) {
3440 req->sym_out = req1.sym_out;
3441 req->defobj_out = req1.defobj_out;
3442 assert(req->defobj_out != NULL);
3446 return (req->sym_out != NULL ? 0 : ESRCH);
3450 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3453 const Obj_Entry *defobj;
3454 const Objlist_Entry *elm;
3460 STAILQ_FOREACH(elm, objlist, link) {
3461 if (donelist_check(dlp, elm->obj))
3463 symlook_init_from_req(&req1, req);
3464 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3465 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3467 defobj = req1.defobj_out;
3468 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3475 req->defobj_out = defobj;
3482 * Search the chain of DAGS cointed to by the given Needed_Entry
3483 * for a symbol of the given name. Each DAG is scanned completely
3484 * before advancing to the next one. Returns a pointer to the symbol,
3485 * or NULL if no definition was found.
3488 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3491 const Needed_Entry *n;
3492 const Obj_Entry *defobj;
3498 symlook_init_from_req(&req1, req);
3499 for (n = needed; n != NULL; n = n->next) {
3500 if (n->obj == NULL ||
3501 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3503 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3505 defobj = req1.defobj_out;
3506 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3512 req->defobj_out = defobj;
3519 * Search the symbol table of a single shared object for a symbol of
3520 * the given name and version, if requested. Returns a pointer to the
3521 * symbol, or NULL if no definition was found. If the object is
3522 * filter, return filtered symbol from filtee.
3524 * The symbol's hash value is passed in for efficiency reasons; that
3525 * eliminates many recomputations of the hash value.
3528 symlook_obj(SymLook *req, const Obj_Entry *obj)
3535 * There is at least one valid hash at this point, and we prefer to use
3536 * the faster GNU version if available.
3538 if (obj->valid_hash_gnu)
3539 mres = symlook_obj2(req, obj);
3541 mres = symlook_obj1(req, obj);
3544 if (obj->needed_filtees != NULL) {
3545 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate);
3546 donelist_init(&donelist);
3547 symlook_init_from_req(&req1, req);
3548 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3550 req->sym_out = req1.sym_out;
3551 req->defobj_out = req1.defobj_out;
3555 if (obj->needed_aux_filtees != NULL) {
3556 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate);
3557 donelist_init(&donelist);
3558 symlook_init_from_req(&req1, req);
3559 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3561 req->sym_out = req1.sym_out;
3562 req->defobj_out = req1.defobj_out;
3570 /* Symbol match routine common to both hash functions */
3572 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3573 const unsigned long symnum)
3576 const Elf_Sym *symp = obj->symtab + symnum;
3577 const char *strp = obj->strtab + symp->st_name;
3579 switch (ELF_ST_TYPE(symp->st_info)) {
3585 if (symp->st_value == 0)
3589 if (symp->st_shndx != SHN_UNDEF)
3591 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3592 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3598 if (strcmp(req->name, strp) != 0)
3601 if (req->ventry == NULL) {
3602 if (obj->versyms != NULL) {
3603 verndx = VER_NDX(obj->versyms[symnum]);
3604 if (verndx > obj->vernum) {
3605 _rtld_error("%s: symbol %s references wrong version %d",
3606 obj->path, obj->strtab + symnum, verndx);
3610 * If we are not called from dlsym (i.e. this is a normal relocation
3611 * from unversioned binary), accept the symbol immediately if it happens
3612 * to have first version after this shared object became versioned.
3613 * Otherwise, if symbol is versioned and not hidden, remember it. If it
3614 * is the only symbol with this name exported by the shared object, it
3615 * will be returned as a match by the calling function. If symbol is
3616 * global (verndx < 2) accept it unconditionally.
3618 if ((req->flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN) {
3619 result->sym_out = symp;
3622 else if (verndx >= VER_NDX_GIVEN) {
3623 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) {
3624 if (result->vsymp == NULL)
3625 result->vsymp = symp;
3631 result->sym_out = symp;
3634 if (obj->versyms == NULL) {
3635 if (object_match_name(obj, req->ventry->name)) {
3636 _rtld_error("%s: object %s should provide version %s for "
3637 "symbol %s", obj_rtld.path, obj->path,
3638 req->ventry->name, obj->strtab + symnum);
3642 verndx = VER_NDX(obj->versyms[symnum]);
3643 if (verndx > obj->vernum) {
3644 _rtld_error("%s: symbol %s references wrong version %d",
3645 obj->path, obj->strtab + symnum, verndx);
3648 if (obj->vertab[verndx].hash != req->ventry->hash ||
3649 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3651 * Version does not match. Look if this is a global symbol and if it is
3652 * not hidden. If global symbol (verndx < 2) is available, use it. Do not
3653 * return symbol if we are called by dlvsym, because dlvsym looks for a
3654 * specific version and default one is not what dlvsym wants.
3656 if ((req->flags & SYMLOOK_DLSYM) || (verndx >= VER_NDX_GIVEN) ||
3657 (obj->versyms[symnum] & VER_NDX_HIDDEN))
3661 result->sym_out = symp;
3666 * Search for symbol using SysV hash function.
3667 * obj->buckets is known not to be NULL at this point; the test for this was
3668 * performed with the obj->valid_hash_sysv assignment.
3671 symlook_obj1(SymLook *req, const Obj_Entry *obj)
3673 unsigned long symnum;
3674 Sym_Match_Result matchres;
3676 matchres.sym_out = NULL;
3677 matchres.vsymp = NULL;
3678 matchres.vcount = 0;
3680 for (symnum = obj->buckets[req->hash % obj->nbuckets];
3681 symnum != STN_UNDEF;
3682 symnum = obj->chains[symnum]) {
3684 if (symnum >= obj->nchains)
3685 return (ESRCH); /* Bad object */
3687 if (matched_symbol(req, obj, &matchres, symnum)) {
3688 req->sym_out = matchres.sym_out;
3689 req->defobj_out = obj;
3693 if (matchres.vcount == 1) {
3694 req->sym_out = matchres.vsymp;
3695 req->defobj_out = obj;
3701 /* Search for symbol using GNU hash function */
3703 symlook_obj2(SymLook *req, const Obj_Entry *obj)
3705 Elf_Addr bloom_word;
3707 unsigned int h1, h2;
3708 unsigned long symnum;
3709 const int c = __ELF_WORD_SIZE;
3710 Sym_Match_Result matchres;
3712 matchres.sym_out = NULL;
3713 matchres.vsymp = NULL;
3714 matchres.vcount = 0;
3716 /* pick right bitmask word from Bloom filter array*/
3717 bloom_word = obj->bloom_gnu[(req->hash_gnu / c) & obj->maskwords_bm_gnu];
3719 /* calculate modulus 32 (64 for x86_64) of gnu hash and its derivative */
3720 h1 = req->hash_gnu & (c - 1);
3721 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (c - 1));
3723 /* Filter out the "definitely not in set" queries */
3724 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
3727 /* Locate hash chain and corresponding value element*/
3728 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
3731 const Elf32_Word *hashval = &obj->chain_zero_gnu[bucket];
3733 if (((*hashval ^ req->hash_gnu) >> 1) == 0)
3735 symnum = hashval - obj->chain_zero_gnu;
3736 if (matched_symbol(req, obj, &matchres, symnum)) {
3737 req->sym_out = matchres.sym_out;
3738 req->defobj_out = obj;
3742 while ((*hashval++ & 1u) == 0);
3743 if (matchres.vcount == 1) {
3744 req->sym_out = matchres.vsymp;
3745 req->defobj_out = obj;
3752 trace_loaded_objects(Obj_Entry *obj)
3754 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
3757 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
3760 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL)
3761 fmt1 = "\t%o => %p (%x)\n";
3763 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL)
3764 fmt2 = "\t%o (%x)\n";
3766 list_containers = _getenv_ld("LD_TRACE_LOADED_OBJECTS_ALL");
3768 for (; obj; obj = obj->next) {
3769 Needed_Entry *needed;
3773 if (list_containers && obj->needed != NULL)
3774 rtld_printf("%s:\n", obj->path);
3775 for (needed = obj->needed; needed; needed = needed->next) {
3776 if (needed->obj != NULL) {
3777 if (needed->obj->traced && !list_containers)
3779 needed->obj->traced = true;
3780 path = needed->obj->path;
3784 name = (char *)obj->strtab + needed->name;
3785 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
3787 fmt = is_lib ? fmt1 : fmt2;
3788 while ((c = *fmt++) != '\0') {
3814 rtld_putstr(main_local);
3817 rtld_putstr(obj_main->path);
3826 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
3839 * Unload a dlopened object and its dependencies from memory and from
3840 * our data structures. It is assumed that the DAG rooted in the
3841 * object has already been unreferenced, and that the object has a
3842 * reference count of 0.
3845 unload_object(Obj_Entry *root)
3850 assert(root->refcount == 0);
3853 * Pass over the DAG removing unreferenced objects from
3854 * appropriate lists.
3856 unlink_object(root);
3858 /* Unmap all objects that are no longer referenced. */
3859 linkp = &obj_list->next;
3860 while ((obj = *linkp) != NULL) {
3861 if (obj->refcount == 0) {
3862 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
3864 dbg("unloading \"%s\"", obj->path);
3865 unload_filtees(root);
3866 munmap(obj->mapbase, obj->mapsize);
3867 linkmap_delete(obj);
3878 unlink_object(Obj_Entry *root)
3882 if (root->refcount == 0) {
3883 /* Remove the object from the RTLD_GLOBAL list. */
3884 objlist_remove(&list_global, root);
3886 /* Remove the object from all objects' DAG lists. */
3887 STAILQ_FOREACH(elm, &root->dagmembers, link) {
3888 objlist_remove(&elm->obj->dldags, root);
3889 if (elm->obj != root)
3890 unlink_object(elm->obj);
3896 ref_dag(Obj_Entry *root)
3900 assert(root->dag_inited);
3901 STAILQ_FOREACH(elm, &root->dagmembers, link)
3902 elm->obj->refcount++;
3906 unref_dag(Obj_Entry *root)
3910 assert(root->dag_inited);
3911 STAILQ_FOREACH(elm, &root->dagmembers, link)
3912 elm->obj->refcount--;
3916 * Common code for MD __tls_get_addr().
3919 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset)
3921 Elf_Addr* dtv = *dtvp;
3922 RtldLockState lockstate;
3924 /* Check dtv generation in case new modules have arrived */
3925 if (dtv[0] != tls_dtv_generation) {
3929 wlock_acquire(rtld_bind_lock, &lockstate);
3930 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
3932 if (to_copy > tls_max_index)
3933 to_copy = tls_max_index;
3934 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
3935 newdtv[0] = tls_dtv_generation;
3936 newdtv[1] = tls_max_index;
3938 lock_release(rtld_bind_lock, &lockstate);
3939 dtv = *dtvp = newdtv;
3942 /* Dynamically allocate module TLS if necessary */
3943 if (!dtv[index + 1]) {
3944 /* Signal safe, wlock will block out signals. */
3945 wlock_acquire(rtld_bind_lock, &lockstate);
3946 if (!dtv[index + 1])
3947 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
3948 lock_release(rtld_bind_lock, &lockstate);
3950 return (void*) (dtv[index + 1] + offset);
3953 #if defined(RTLD_STATIC_TLS_VARIANT_II)
3956 * Allocate the static TLS area. Return a pointer to the TCB. The
3957 * static area is based on negative offsets relative to the tcb.
3959 * The TCB contains an errno pointer for the system call layer, but because
3960 * we are the RTLD we really have no idea how the caller was compiled so
3961 * the information has to be passed in. errno can either be:
3963 * type 0 errno is a simple non-TLS global pointer.
3964 * (special case for e.g. libc_rtld)
3965 * type 1 errno accessed by GOT entry (dynamically linked programs)
3966 * type 2 errno accessed by %gs:OFFSET (statically linked programs)
3969 allocate_tls(Obj_Entry *objs)
3974 struct tls_tcb *tcb;
3979 * Allocate the new TCB. static TLS storage is placed just before the
3980 * TCB to support the %gs:OFFSET (negative offset) model.
3982 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
3983 ~RTLD_STATIC_TLS_ALIGN_MASK;
3984 tcb = malloc(data_size + sizeof(*tcb));
3985 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */
3987 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr);
3988 dtv = malloc(dtv_size);
3989 bzero(dtv, dtv_size);
3991 #ifdef RTLD_TCB_HAS_SELF_POINTER
3992 tcb->tcb_self = tcb;
3995 tcb->tcb_pthread = NULL;
3997 dtv[0] = tls_dtv_generation;
3998 dtv[1] = tls_max_index;
4000 for (obj = objs; obj; obj = obj->next) {
4001 if (obj->tlsoffset) {
4002 addr = (Elf_Addr)tcb - obj->tlsoffset;
4003 memset((void *)(addr + obj->tlsinitsize),
4004 0, obj->tlssize - obj->tlsinitsize);
4006 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4007 dtv[obj->tlsindex + 1] = addr;
4014 free_tls(struct tls_tcb *tcb)
4018 Elf_Addr tls_start, tls_end;
4021 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
4022 ~RTLD_STATIC_TLS_ALIGN_MASK;
4026 tls_end = (Elf_Addr)tcb;
4027 tls_start = (Elf_Addr)tcb - data_size;
4028 for (i = 0; i < dtv_size; i++) {
4029 if (dtv[i+2] != 0 && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) {
4030 free((void *)dtv[i+2]);
4034 free((void*) tls_start);
4038 #error "Unsupported TLS layout"
4042 * Allocate TLS block for module with given index.
4045 allocate_module_tls(int index)
4050 for (obj = obj_list; obj; obj = obj->next) {
4051 if (obj->tlsindex == index)
4055 _rtld_error("Can't find module with TLS index %d", index);
4059 p = malloc(obj->tlssize);
4061 _rtld_error("Cannot allocate TLS block for index %d", index);
4064 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4065 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4071 allocate_tls_offset(Obj_Entry *obj)
4078 if (obj->tlssize == 0) {
4079 obj->tls_done = true;
4083 if (obj->tlsindex == 1)
4084 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4086 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4087 obj->tlssize, obj->tlsalign);
4090 * If we have already fixed the size of the static TLS block, we
4091 * must stay within that size. When allocating the static TLS, we
4092 * leave a small amount of space spare to be used for dynamically
4093 * loading modules which use static TLS.
4095 if (tls_static_space) {
4096 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4100 tls_last_offset = obj->tlsoffset = off;
4101 tls_last_size = obj->tlssize;
4102 obj->tls_done = true;
4108 free_tls_offset(Obj_Entry *obj)
4110 #ifdef RTLD_STATIC_TLS_VARIANT_II
4112 * If we were the last thing to allocate out of the static TLS
4113 * block, we give our space back to the 'allocator'. This is a
4114 * simplistic workaround to allow libGL.so.1 to be loaded and
4115 * unloaded multiple times. We only handle the Variant II
4116 * mechanism for now - this really needs a proper allocator.
4118 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4119 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4120 tls_last_offset -= obj->tlssize;
4127 _rtld_allocate_tls(void)
4129 struct tls_tcb *new_tcb;
4130 RtldLockState lockstate;
4132 wlock_acquire(rtld_bind_lock, &lockstate);
4133 new_tcb = allocate_tls(obj_list);
4134 lock_release(rtld_bind_lock, &lockstate);
4139 _rtld_free_tls(struct tls_tcb *tcb)
4141 RtldLockState lockstate;
4143 wlock_acquire(rtld_bind_lock, &lockstate);
4145 lock_release(rtld_bind_lock, &lockstate);
4149 object_add_name(Obj_Entry *obj, const char *name)
4155 entry = malloc(sizeof(Name_Entry) + len);
4157 if (entry != NULL) {
4158 strcpy(entry->name, name);
4159 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4164 object_match_name(const Obj_Entry *obj, const char *name)
4168 STAILQ_FOREACH(entry, &obj->names, link) {
4169 if (strcmp(name, entry->name) == 0)
4176 locate_dependency(const Obj_Entry *obj, const char *name)
4178 const Objlist_Entry *entry;
4179 const Needed_Entry *needed;
4181 STAILQ_FOREACH(entry, &list_main, link) {
4182 if (object_match_name(entry->obj, name))
4186 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4187 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4188 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4190 * If there is DT_NEEDED for the name we are looking for,
4191 * we are all set. Note that object might not be found if
4192 * dependency was not loaded yet, so the function can
4193 * return NULL here. This is expected and handled
4194 * properly by the caller.
4196 return (needed->obj);
4199 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4205 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4206 const Elf_Vernaux *vna)
4208 const Elf_Verdef *vd;
4209 const char *vername;
4211 vername = refobj->strtab + vna->vna_name;
4212 vd = depobj->verdef;
4214 _rtld_error("%s: version %s required by %s not defined",
4215 depobj->path, vername, refobj->path);
4219 if (vd->vd_version != VER_DEF_CURRENT) {
4220 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4221 depobj->path, vd->vd_version);
4224 if (vna->vna_hash == vd->vd_hash) {
4225 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4226 ((char *)vd + vd->vd_aux);
4227 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4230 if (vd->vd_next == 0)
4232 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4234 if (vna->vna_flags & VER_FLG_WEAK)
4236 _rtld_error("%s: version %s required by %s not found",
4237 depobj->path, vername, refobj->path);
4242 rtld_verify_object_versions(Obj_Entry *obj)
4244 const Elf_Verneed *vn;
4245 const Elf_Verdef *vd;
4246 const Elf_Verdaux *vda;
4247 const Elf_Vernaux *vna;
4248 const Obj_Entry *depobj;
4249 int maxvernum, vernum;
4253 * Walk over defined and required version records and figure out
4254 * max index used by any of them. Do very basic sanity checking
4258 while (vn != NULL) {
4259 if (vn->vn_version != VER_NEED_CURRENT) {
4260 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4261 obj->path, vn->vn_version);
4264 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4266 vernum = VER_NEED_IDX(vna->vna_other);
4267 if (vernum > maxvernum)
4269 if (vna->vna_next == 0)
4271 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4273 if (vn->vn_next == 0)
4275 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4279 while (vd != NULL) {
4280 if (vd->vd_version != VER_DEF_CURRENT) {
4281 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4282 obj->path, vd->vd_version);
4285 vernum = VER_DEF_IDX(vd->vd_ndx);
4286 if (vernum > maxvernum)
4288 if (vd->vd_next == 0)
4290 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4297 * Store version information in array indexable by version index.
4298 * Verify that object version requirements are satisfied along the
4301 obj->vernum = maxvernum + 1;
4302 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry));
4305 while (vd != NULL) {
4306 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4307 vernum = VER_DEF_IDX(vd->vd_ndx);
4308 assert(vernum <= maxvernum);
4309 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4310 obj->vertab[vernum].hash = vd->vd_hash;
4311 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4312 obj->vertab[vernum].file = NULL;
4313 obj->vertab[vernum].flags = 0;
4315 if (vd->vd_next == 0)
4317 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4321 while (vn != NULL) {
4322 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4325 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4327 if (check_object_provided_version(obj, depobj, vna))
4329 vernum = VER_NEED_IDX(vna->vna_other);
4330 assert(vernum <= maxvernum);
4331 obj->vertab[vernum].hash = vna->vna_hash;
4332 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4333 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4334 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4335 VER_INFO_HIDDEN : 0;
4336 if (vna->vna_next == 0)
4338 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4340 if (vn->vn_next == 0)
4342 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4348 rtld_verify_versions(const Objlist *objlist)
4350 Objlist_Entry *entry;
4354 STAILQ_FOREACH(entry, objlist, link) {
4356 * Skip dummy objects or objects that have their version requirements
4359 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4361 if (rtld_verify_object_versions(entry->obj) == -1) {
4363 if (ld_tracing == NULL)
4367 if (rc == 0 || ld_tracing != NULL)
4368 rc = rtld_verify_object_versions(&obj_rtld);
4373 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4378 vernum = VER_NDX(obj->versyms[symnum]);
4379 if (vernum >= obj->vernum) {
4380 _rtld_error("%s: symbol %s has wrong verneed value %d",
4381 obj->path, obj->strtab + symnum, vernum);
4382 } else if (obj->vertab[vernum].hash != 0) {
4383 return &obj->vertab[vernum];
4390 _rtld_get_stack_prot(void)
4393 return (stack_prot);
4397 map_stacks_exec(RtldLockState *lockstate)
4401 * Stack protection must be implemented in the kernel before the dynamic
4402 * linker can handle PT_GNU_STACK sections.
4403 * The following is the FreeBSD implementation of map_stacks_exec()
4404 * void (*thr_map_stacks_exec)(void);
4406 * if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4408 * thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4409 * get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4410 * if (thr_map_stacks_exec != NULL) {
4411 * stack_prot |= PROT_EXEC;
4412 * thr_map_stacks_exec();
4418 symlook_init(SymLook *dst, const char *name)
4421 bzero(dst, sizeof(*dst));
4423 dst->hash = elf_hash(name);
4424 dst->hash_gnu = gnu_hash(name);
4428 symlook_init_from_req(SymLook *dst, const SymLook *src)
4431 dst->name = src->name;
4432 dst->hash = src->hash;
4433 dst->hash_gnu = src->hash_gnu;
4434 dst->ventry = src->ventry;
4435 dst->flags = src->flags;
4436 dst->defobj_out = NULL;
4437 dst->sym_out = NULL;
4438 dst->lockstate = src->lockstate;
4441 #ifdef ENABLE_OSRELDATE
4443 * Overrides for libc_pic-provided functions.
4447 __getosreldate(void)
4457 oid[1] = KERN_OSRELDATE;
4459 len = sizeof(osrel);
4460 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4461 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4468 * No unresolved symbols for rtld.
4471 __pthread_cxa_finalize(struct dl_phdr_info *a)
4476 rtld_strerror(int errnum)
4479 if (errnum < 0 || errnum >= sys_nerr)
4480 return ("Unknown error");
4481 return (sys_errlist[errnum]);