2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * Copyright 2009-2012 Konstantin Belousov <kib@FreeBSD.ORG>.
5 * Copyright 2012 John Marino <draco@marino.st>.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 * Dynamic linker for ELF.
34 * John Polstra <jdp@polstra.com>.
38 #error "GCC is needed to compile this file"
41 #include <sys/param.h>
42 #include <sys/mount.h>
45 #include <sys/sysctl.h>
47 #include <sys/utsname.h>
48 #include <sys/ktrace.h>
49 #include <sys/resident.h>
52 #include <machine/tls.h>
67 #include "rtld_printf.h"
70 #define PATH_RTLD "/usr/libexec/ld-elf.so.2"
71 #define LD_ARY_CACHE 16
74 typedef void (*func_ptr_type)();
75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
78 * Function declarations.
80 static const char *_getenv_ld(const char *id);
81 static void die(void) __dead2;
82 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
83 const Elf_Dyn **, const Elf_Dyn **);
84 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
86 static void digest_dynamic(Obj_Entry *, int);
87 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
88 static Obj_Entry *dlcheck(void *);
89 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
90 int lo_flags, int mode, RtldLockState *lockstate);
91 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
92 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
93 static bool donelist_check(DoneList *, const Obj_Entry *);
94 static void errmsg_restore(char *);
95 static char *errmsg_save(void);
96 static void *fill_search_info(const char *, size_t, void *);
97 static char *find_library(const char *, const Obj_Entry *);
98 static const char *gethints(bool);
99 static void init_dag(Obj_Entry *);
100 static void init_rtld(caddr_t, Elf_Auxinfo **);
101 static void initlist_add_neededs(Needed_Entry *, Objlist *);
102 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
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 *, int fd, 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 objlist_clear(Objlist *);
115 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
116 static void objlist_init(Objlist *);
117 static void objlist_push_head(Objlist *, Obj_Entry *);
118 static void objlist_push_tail(Objlist *, Obj_Entry *);
119 static void objlist_remove(Objlist *, Obj_Entry *);
120 static void *path_enumerate(const char *, path_enum_proc, void *);
121 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
122 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
123 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
124 int flags, RtldLockState *lockstate);
125 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
127 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
128 int flags, RtldLockState *lockstate);
129 static int rtld_dirname(const char *, char *);
130 static int rtld_dirname_abs(const char *, char *);
131 static void *rtld_dlopen(const char *name, int fd, int mode);
132 static void rtld_exit(void);
133 static char *search_library_path(const char *, const char *);
134 static const void **get_program_var_addr(const char *, RtldLockState *);
135 static void set_program_var(const char *, const void *);
136 static int symlook_default(SymLook *, const Obj_Entry *refobj);
137 static int symlook_global(SymLook *, DoneList *);
138 static void symlook_init_from_req(SymLook *, const SymLook *);
139 static int symlook_list(SymLook *, const Objlist *, DoneList *);
140 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
141 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
142 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
143 static void trace_loaded_objects(Obj_Entry *);
144 static void unlink_object(Obj_Entry *);
145 static void unload_object(Obj_Entry *);
146 static void unref_dag(Obj_Entry *);
147 static void ref_dag(Obj_Entry *);
148 static char *origin_subst_one(char *, const char *, const char *, bool);
149 static char *origin_subst(char *, const char *);
150 static void preinit_main(void);
151 static int rtld_verify_versions(const Objlist *);
152 static int rtld_verify_object_versions(Obj_Entry *);
153 static void object_add_name(Obj_Entry *, const char *);
154 static int object_match_name(const Obj_Entry *, const char *);
155 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
156 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
157 struct dl_phdr_info *phdr_info);
158 static uint_fast32_t gnu_hash (const char *);
159 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
160 const unsigned long);
162 void r_debug_state(struct r_debug *, struct link_map *) __noinline;
167 static char *error_message; /* Message for dlerror(), or NULL */
168 struct r_debug r_debug; /* for GDB; */
169 static bool libmap_disable; /* Disable libmap */
170 static bool ld_loadfltr; /* Immediate filters processing */
171 static char *libmap_override; /* Maps to use in addition to libmap.conf */
172 static bool trust; /* False for setuid and setgid programs */
173 static bool dangerous_ld_env; /* True if environment variables have been
174 used to affect the libraries loaded */
175 static const char *ld_bind_now; /* Environment variable for immediate binding */
176 static const char *ld_debug; /* Environment variable for debugging */
177 static const char *ld_library_path; /* Environment variable for search path */
178 static char *ld_preload; /* Environment variable for libraries to
180 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */
181 static const char *ld_tracing; /* Called from ldd to print libs */
182 static const char *ld_utrace; /* Use utrace() to log events. */
183 static int (*rtld_functrace)( /* Optional function call tracing hook */
184 const char *caller_obj,
185 const char *callee_obj,
186 const char *callee_func,
188 static const Obj_Entry *rtld_functrace_obj; /* Object thereof */
189 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
190 static Obj_Entry **obj_tail; /* Link field of last object in list */
191 static Obj_Entry **preload_tail;
192 static Obj_Entry *obj_main; /* The main program shared object */
193 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
194 static unsigned int obj_count; /* Number of objects in obj_list */
195 static unsigned int obj_loads; /* Number of objects in obj_list */
197 static int ld_resident; /* Non-zero if resident */
198 static const char *ld_ary[LD_ARY_CACHE];
200 static Objlist initlist;
202 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
203 STAILQ_HEAD_INITIALIZER(list_global);
204 static Objlist list_main = /* Objects loaded at program startup */
205 STAILQ_HEAD_INITIALIZER(list_main);
206 static Objlist list_fini = /* Objects needing fini() calls */
207 STAILQ_HEAD_INITIALIZER(list_fini);
209 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */
210 const char *__ld_sharedlib_base;
212 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
214 extern Elf_Dyn _DYNAMIC;
215 #pragma weak _DYNAMIC
216 #ifndef RTLD_IS_DYNAMIC
217 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
220 #ifdef ENABLE_OSRELDATE
224 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
225 static int max_stack_flags;
228 * Global declarations normally provided by crt1. The dynamic linker is
229 * not built with crt1, so we have to provide them ourselves.
235 * Used to pass argc, argv to init functions.
241 * Globals to control TLS allocation.
243 size_t tls_last_offset; /* Static TLS offset of last module */
244 size_t tls_last_size; /* Static TLS size of last module */
245 size_t tls_static_space; /* Static TLS space allocated */
246 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
247 int tls_max_index = 1; /* Largest module index allocated */
250 * Fill in a DoneList with an allocation large enough to hold all of
251 * the currently-loaded objects. Keep this as a macro since it calls
252 * alloca and we want that to occur within the scope of the caller.
254 #define donelist_init(dlp) \
255 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
256 assert((dlp)->objs != NULL), \
257 (dlp)->num_alloc = obj_count, \
260 #define UTRACE_DLOPEN_START 1
261 #define UTRACE_DLOPEN_STOP 2
262 #define UTRACE_DLCLOSE_START 3
263 #define UTRACE_DLCLOSE_STOP 4
264 #define UTRACE_LOAD_OBJECT 5
265 #define UTRACE_UNLOAD_OBJECT 6
266 #define UTRACE_ADD_RUNDEP 7
267 #define UTRACE_PRELOAD_FINISHED 8
268 #define UTRACE_INIT_CALL 9
269 #define UTRACE_FINI_CALL 10
272 char sig[4]; /* 'RTLD' */
275 void *mapbase; /* Used for 'parent' and 'init/fini' */
277 int refcnt; /* Used for 'mode' */
278 char name[MAXPATHLEN];
281 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
282 if (ld_utrace != NULL) \
283 ld_utrace_log(e, h, mb, ms, r, n); \
287 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
288 int refcnt, const char *name)
290 struct utrace_rtld ut;
298 ut.mapbase = mapbase;
299 ut.mapsize = mapsize;
301 bzero(ut.name, sizeof(ut.name));
303 strlcpy(ut.name, name, sizeof(ut.name));
304 utrace(&ut, sizeof(ut));
308 * Main entry point for dynamic linking. The first argument is the
309 * stack pointer. The stack is expected to be laid out as described
310 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
311 * Specifically, the stack pointer points to a word containing
312 * ARGC. Following that in the stack is a null-terminated sequence
313 * of pointers to argument strings. Then comes a null-terminated
314 * sequence of pointers to environment strings. Finally, there is a
315 * sequence of "auxiliary vector" entries.
317 * The second argument points to a place to store the dynamic linker's
318 * exit procedure pointer and the third to a place to store the main
321 * The return value is the main program's entry point.
324 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
326 Elf_Auxinfo *aux_info[AT_COUNT];
334 Objlist_Entry *entry;
337 /* marino: DO NOT MOVE THESE VARIABLES TO _rtld
338 Obj_Entry **preload_tail;
340 from global to here. It will break the DWARF2 unwind scheme.
341 The system compilers were unaffected, but not gcc 4.6
345 * On entry, the dynamic linker itself has not been relocated yet.
346 * Be very careful not to reference any global data until after
347 * init_rtld has returned. It is OK to reference file-scope statics
348 * and string constants, and to call static and global functions.
351 /* Find the auxiliary vector on the stack. */
354 sp += argc + 1; /* Skip over arguments and NULL terminator */
358 * If we aren't already resident we have to dig out some more info.
359 * Note that auxinfo does not exist when we are resident.
361 * I'm not sure about the ld_resident check. It seems to read zero
362 * prior to relocation, which is what we want. When running from a
363 * resident copy everything will be relocated so we are definitely
366 if (ld_resident == 0) {
367 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
369 aux = (Elf_Auxinfo *) sp;
371 /* Digest the auxiliary vector. */
372 for (i = 0; i < AT_COUNT; i++)
374 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
375 if (auxp->a_type < AT_COUNT)
376 aux_info[auxp->a_type] = auxp;
379 /* Initialize and relocate ourselves. */
380 assert(aux_info[AT_BASE] != NULL);
381 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
384 ld_index = 0; /* don't use old env cache in case we are resident */
385 __progname = obj_rtld.path;
386 argv0 = argv[0] != NULL ? argv[0] : "(null)";
391 trust = !issetugid();
393 ld_bind_now = _getenv_ld("LD_BIND_NOW");
395 * If the process is tainted, then we un-set the dangerous environment
396 * variables. The process will be marked as tainted until setuid(2)
397 * is called. If any child process calls setuid(2) we do not want any
398 * future processes to honor the potentially un-safe variables.
401 if ( unsetenv("LD_DEBUG")
402 || unsetenv("LD_PRELOAD")
403 || unsetenv("LD_LIBRARY_PATH")
404 || unsetenv("LD_ELF_HINTS_PATH")
405 || unsetenv("LD_LIBMAP")
406 || unsetenv("LD_LIBMAP_DISABLE")
407 || unsetenv("LD_LOADFLTR")
408 || unsetenv("LD_SHAREDLIB_BASE")
410 _rtld_error("environment corrupt; aborting");
414 __ld_sharedlib_base = _getenv_ld("LD_SHAREDLIB_BASE");
415 ld_debug = _getenv_ld("LD_DEBUG");
416 libmap_disable = _getenv_ld("LD_LIBMAP_DISABLE") != NULL;
417 libmap_override = (char *)_getenv_ld("LD_LIBMAP");
418 ld_library_path = _getenv_ld("LD_LIBRARY_PATH");
419 ld_preload = (char *)_getenv_ld("LD_PRELOAD");
420 ld_elf_hints_path = _getenv_ld("LD_ELF_HINTS_PATH");
421 ld_loadfltr = _getenv_ld("LD_LOADFLTR") != NULL;
422 dangerous_ld_env = (ld_library_path != NULL)
423 || (ld_preload != NULL)
424 || (ld_elf_hints_path != NULL)
426 || (libmap_override != NULL)
429 ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS");
430 ld_utrace = _getenv_ld("LD_UTRACE");
432 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
433 ld_elf_hints_path = _PATH_ELF_HINTS;
435 if (ld_debug != NULL && *ld_debug != '\0')
437 dbg("%s is initialized, base address = %p", __progname,
438 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
439 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
440 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
442 dbg("initializing thread locks");
446 * If we are resident we can skip work that we have already done.
447 * Note that the stack is reset and there is no Elf_Auxinfo
448 * when running from a resident image, and the static globals setup
449 * between here and resident_skip will have already been setup.
455 * Load the main program, or process its program header if it is
458 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
459 int fd = aux_info[AT_EXECFD]->a_un.a_val;
460 dbg("loading main program");
461 obj_main = map_object(fd, argv0, NULL);
463 if (obj_main == NULL)
465 max_stack_flags = obj->stack_flags;
466 } else { /* Main program already loaded. */
467 const Elf_Phdr *phdr;
471 dbg("processing main program's program header");
472 assert(aux_info[AT_PHDR] != NULL);
473 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
474 assert(aux_info[AT_PHNUM] != NULL);
475 phnum = aux_info[AT_PHNUM]->a_un.a_val;
476 assert(aux_info[AT_PHENT] != NULL);
477 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
478 assert(aux_info[AT_ENTRY] != NULL);
479 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
480 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
484 char buf[MAXPATHLEN];
485 if (aux_info[AT_EXECPATH] != NULL) {
488 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
489 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
490 if (kexecpath[0] == '/')
491 obj_main->path = kexecpath;
492 else if (getcwd(buf, sizeof(buf)) == NULL ||
493 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
494 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
495 obj_main->path = xstrdup(argv0);
497 obj_main->path = xstrdup(buf);
499 char resolved[MAXPATHLEN];
500 dbg("No AT_EXECPATH");
501 if (argv0[0] == '/') {
502 if (realpath(argv0, resolved) != NULL)
503 obj_main->path = xstrdup(resolved);
505 obj_main->path = xstrdup(argv0);
507 if (getcwd(buf, sizeof(buf)) != NULL
508 && strlcat(buf, "/", sizeof(buf)) < sizeof(buf)
509 && strlcat(buf, argv0, sizeof (buf)) < sizeof(buf)
510 && access(buf, R_OK) == 0
511 && realpath(buf, resolved) != NULL)
512 obj_main->path = xstrdup(resolved);
514 obj_main->path = xstrdup(argv0);
517 dbg("obj_main path %s", obj_main->path);
518 obj_main->mainprog = true;
520 if (aux_info[AT_STACKPROT] != NULL &&
521 aux_info[AT_STACKPROT]->a_un.a_val != 0)
522 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
525 * Get the actual dynamic linker pathname from the executable if
526 * possible. (It should always be possible.) That ensures that
527 * gdb will find the right dynamic linker even if a non-standard
530 if (obj_main->interp != NULL &&
531 strcmp(obj_main->interp, obj_rtld.path) != 0) {
533 obj_rtld.path = xstrdup(obj_main->interp);
534 __progname = obj_rtld.path;
537 digest_dynamic(obj_main, 0);
538 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
539 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
540 obj_main->dynsymcount);
542 linkmap_add(obj_main);
543 linkmap_add(&obj_rtld);
545 /* Link the main program into the list of objects. */
546 *obj_tail = obj_main;
547 obj_tail = &obj_main->next;
551 /* Initialize a fake symbol for resolving undefined weak references. */
552 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
553 sym_zero.st_shndx = SHN_UNDEF;
554 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
557 libmap_disable = (bool)lm_init(libmap_override);
559 dbg("loading LD_PRELOAD libraries");
560 if (load_preload_objects() == -1)
562 preload_tail = obj_tail;
564 dbg("loading needed objects");
565 if (load_needed_objects(obj_main, 0) == -1)
568 /* Make a list of all objects loaded at startup. */
569 for (obj = obj_list; obj != NULL; obj = obj->next) {
570 objlist_push_tail(&list_main, obj);
574 dbg("checking for required versions");
575 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
580 if (ld_tracing) { /* We're done */
581 trace_loaded_objects(obj_main);
585 if (ld_resident) /* XXX clean this up! */
588 if (_getenv_ld("LD_DUMP_REL_PRE") != NULL) {
589 dump_relocations(obj_main);
593 /* setup TLS for main thread */
594 dbg("initializing initial thread local storage");
595 STAILQ_FOREACH(entry, &list_main, link) {
597 * Allocate all the initial objects out of the static TLS
598 * block even if they didn't ask for it.
600 allocate_tls_offset(entry->obj);
603 tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA;
606 * Do not try to allocate the TLS here, let libc do it itself.
607 * (crt1 for the program will call _init_tls())
610 if (relocate_objects(obj_main,
611 ld_bind_now != NULL && *ld_bind_now != '\0',
612 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
615 dbg("doing copy relocations");
616 if (do_copy_relocations(obj_main) == -1)
621 if (_getenv_ld("LD_RESIDENT_UNREGISTER_NOW")) {
622 if (exec_sys_unregister(-1) < 0) {
623 dbg("exec_sys_unregister failed %d\n", errno);
626 dbg("exec_sys_unregister success\n");
630 if (_getenv_ld("LD_DUMP_REL_POST") != NULL) {
631 dump_relocations(obj_main);
635 dbg("initializing key program variables");
636 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
637 set_program_var("environ", env);
638 set_program_var("__elf_aux_vector", aux);
640 if (_getenv_ld("LD_RESIDENT_REGISTER_NOW")) {
641 extern void resident_start(void);
643 if (exec_sys_register(resident_start) < 0) {
644 dbg("exec_sys_register failed %d\n", errno);
647 dbg("exec_sys_register success\n");
651 /* Make a list of init functions to call. */
652 objlist_init(&initlist);
653 initlist_add_objects(obj_list, preload_tail, &initlist);
655 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
657 map_stacks_exec(NULL);
659 dbg("resolving ifuncs");
660 if (resolve_objects_ifunc(obj_main,
661 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
666 * Do NOT call the initlist here, give libc a chance to set up
667 * the initial TLS segment. crt1 will then call _rtld_call_init().
670 dbg("transferring control to program entry point = %p", obj_main->entry);
672 /* Return the exit procedure and the program entry point. */
673 *exit_proc = rtld_exit;
675 return (func_ptr_type) obj_main->entry;
679 * Call the initialization list for dynamically loaded libraries.
680 * (called from crt1.c).
683 _rtld_call_init(void)
685 RtldLockState lockstate;
688 if (!obj_main->note_present && obj_main->valid_hash_gnu) {
690 * The use of a linker script with a PHDRS directive that does not include
691 * PT_NOTE will block the crt_no_init note. In this case we'll look for the
692 * recently added GNU hash dynamic tag which gets built by default. It is
693 * extremely unlikely to find a pre-3.1 binary without a PT_NOTE header and
694 * a gnu hash tag. If gnu hash found, consider binary to use new crt code.
696 obj_main->crt_no_init = true;
697 dbg("Setting crt_no_init without presence of PT_NOTE header");
700 wlock_acquire(rtld_bind_lock, &lockstate);
701 if (obj_main->crt_no_init)
705 * Make sure we don't call the main program's init and fini functions
706 * for binaries linked with old crt1 which calls _init itself.
708 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
709 obj_main->init_array = obj_main->fini_array = (Elf_Addr)NULL;
711 objlist_call_init(&initlist, &lockstate);
712 objlist_clear(&initlist);
713 dbg("loading filtees");
714 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
715 if (ld_loadfltr || obj->z_loadfltr)
716 load_filtees(obj, 0, &lockstate);
718 lock_release(rtld_bind_lock, &lockstate);
722 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
727 ptr = (void *)make_function_pointer(def, obj);
728 target = ((Elf_Addr (*)(void))ptr)();
729 return ((void *)target);
733 _rtld_bind(Obj_Entry *obj, Elf_Size reloff, void *stack)
737 const Obj_Entry *defobj;
740 RtldLockState lockstate;
742 rlock_acquire(rtld_bind_lock, &lockstate);
743 if (sigsetjmp(lockstate.env, 0) != 0)
744 lock_upgrade(rtld_bind_lock, &lockstate);
746 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
748 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
750 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
751 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
755 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
756 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
758 target = (Elf_Addr)(defobj->relocbase + def->st_value);
760 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
761 defobj->strtab + def->st_name, basename(obj->path),
762 (void *)target, basename(defobj->path));
765 * If we have a function call tracing hook, and the
766 * hook would like to keep tracing this one function,
767 * prevent the relocation so we will wind up here
768 * the next time again.
770 * We don't want to functrace calls from the functracer
771 * to avoid recursive loops.
773 if (rtld_functrace != NULL && obj != rtld_functrace_obj) {
774 if (rtld_functrace(obj->path,
776 defobj->strtab + def->st_name,
778 lock_release(rtld_bind_lock, &lockstate);
784 * Write the new contents for the jmpslot. Note that depending on
785 * architecture, the value which we need to return back to the
786 * lazy binding trampoline may or may not be the target
787 * address. The value returned from reloc_jmpslot() is the value
788 * that the trampoline needs.
790 target = reloc_jmpslot(where, target, defobj, obj, rel);
791 lock_release(rtld_bind_lock, &lockstate);
796 * Error reporting function. Use it like printf. If formats the message
797 * into a buffer, and sets things up so that the next call to dlerror()
798 * will return the message.
801 _rtld_error(const char *fmt, ...)
803 static char buf[512];
807 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
813 * Return a dynamically-allocated copy of the current error message, if any.
818 return error_message == NULL ? NULL : xstrdup(error_message);
822 * Restore the current error message from a copy which was previously saved
823 * by errmsg_save(). The copy is freed.
826 errmsg_restore(char *saved_msg)
828 if (saved_msg == NULL)
829 error_message = NULL;
831 _rtld_error("%s", saved_msg);
837 basename(const char *name)
839 const char *p = strrchr(name, '/');
840 return p != NULL ? p + 1 : name;
843 static struct utsname uts;
846 origin_subst_one(char *real, const char *kw, const char *subst,
849 char *p, *p1, *res, *resp;
850 int subst_len, kw_len, subst_count, old_len, new_len;
855 * First, count the number of the keyword occurences, to
856 * preallocate the final string.
858 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
865 * If the keyword is not found, just return.
867 if (subst_count == 0)
868 return (may_free ? real : xstrdup(real));
871 * There is indeed something to substitute. Calculate the
872 * length of the resulting string, and allocate it.
874 subst_len = strlen(subst);
875 old_len = strlen(real);
876 new_len = old_len + (subst_len - kw_len) * subst_count;
877 res = xmalloc(new_len + 1);
880 * Now, execute the substitution loop.
882 for (p = real, resp = res, *resp = '\0';;) {
885 /* Copy the prefix before keyword. */
886 memcpy(resp, p, p1 - p);
888 /* Keyword replacement. */
889 memcpy(resp, subst, subst_len);
897 /* Copy to the end of string and finish. */
905 origin_subst(char *real, const char *origin_path)
907 char *res1, *res2, *res3, *res4;
909 if (uts.sysname[0] == '\0') {
910 if (uname(&uts) != 0) {
911 _rtld_error("utsname failed: %d", errno);
915 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false);
916 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true);
917 res3 = origin_subst_one(res2, "$OSREL", uts.release, true);
918 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true);
925 const char *msg = dlerror();
929 rtld_fdputstr(STDERR_FILENO, msg);
930 rtld_fdputchar(STDERR_FILENO, '\n');
935 * Process a shared object's DYNAMIC section, and save the important
936 * information in its Obj_Entry structure.
939 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
940 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
943 Needed_Entry **needed_tail = &obj->needed;
944 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
945 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
946 const Elf_Hashelt *hashtab;
947 const Elf32_Word *hashval;
948 Elf32_Word bkt, nmaskwords;
951 int plttype = DT_REL;
957 obj->bind_now = false;
958 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
959 switch (dynp->d_tag) {
962 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
966 obj->relsize = dynp->d_un.d_val;
970 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
974 obj->pltrel = (const Elf_Rel *)
975 (obj->relocbase + dynp->d_un.d_ptr);
979 obj->pltrelsize = dynp->d_un.d_val;
983 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
987 obj->relasize = dynp->d_un.d_val;
991 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
995 plttype = dynp->d_un.d_val;
996 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1000 obj->symtab = (const Elf_Sym *)
1001 (obj->relocbase + dynp->d_un.d_ptr);
1005 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1009 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
1013 obj->strsize = dynp->d_un.d_val;
1017 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
1022 obj->verneednum = dynp->d_un.d_val;
1026 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
1031 obj->verdefnum = dynp->d_un.d_val;
1035 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1041 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1043 obj->nbuckets = hashtab[0];
1044 obj->nchains = hashtab[1];
1045 obj->buckets = hashtab + 2;
1046 obj->chains = obj->buckets + obj->nbuckets;
1047 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1048 obj->buckets != NULL;
1054 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1056 obj->nbuckets_gnu = hashtab[0];
1057 obj->symndx_gnu = hashtab[1];
1058 nmaskwords = hashtab[2];
1059 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1060 /* Number of bitmask words is required to be power of 2 */
1061 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0);
1062 obj->maskwords_bm_gnu = nmaskwords - 1;
1063 obj->shift2_gnu = hashtab[3];
1064 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
1065 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1066 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1068 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 &&
1069 obj->buckets_gnu != NULL;
1075 Needed_Entry *nep = NEW(Needed_Entry);
1076 nep->name = dynp->d_un.d_val;
1081 needed_tail = &nep->next;
1087 Needed_Entry *nep = NEW(Needed_Entry);
1088 nep->name = dynp->d_un.d_val;
1092 *needed_filtees_tail = nep;
1093 needed_filtees_tail = &nep->next;
1099 Needed_Entry *nep = NEW(Needed_Entry);
1100 nep->name = dynp->d_un.d_val;
1104 *needed_aux_filtees_tail = nep;
1105 needed_aux_filtees_tail = &nep->next;
1110 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1114 obj->textrel = true;
1118 obj->symbolic = true;
1123 * We have to wait until later to process this, because we
1124 * might not have gotten the address of the string table yet.
1134 *dyn_runpath = dynp;
1138 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1142 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1145 case DT_PREINIT_ARRAY:
1146 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1150 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1154 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1157 case DT_PREINIT_ARRAYSZ:
1158 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1161 case DT_INIT_ARRAYSZ:
1162 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1165 case DT_FINI_ARRAYSZ:
1166 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1170 /* XXX - not implemented yet */
1172 dbg("Filling in DT_DEBUG entry");
1173 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1177 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1178 obj->z_origin = true;
1179 if (dynp->d_un.d_val & DF_SYMBOLIC)
1180 obj->symbolic = true;
1181 if (dynp->d_un.d_val & DF_TEXTREL)
1182 obj->textrel = true;
1183 if (dynp->d_un.d_val & DF_BIND_NOW)
1184 obj->bind_now = true;
1185 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1190 if (dynp->d_un.d_val & DF_1_NOOPEN)
1191 obj->z_noopen = true;
1192 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1193 obj->z_origin = true;
1194 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1196 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1197 obj->bind_now = true;
1198 if (dynp->d_un.d_val & DF_1_NODELETE)
1199 obj->z_nodelete = true;
1200 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1201 obj->z_loadfltr = true;
1202 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1203 obj->z_nodeflib = true;
1208 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1215 obj->traced = false;
1217 if (plttype == DT_RELA) {
1218 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1220 obj->pltrelasize = obj->pltrelsize;
1221 obj->pltrelsize = 0;
1224 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1225 if (obj->valid_hash_sysv)
1226 obj->dynsymcount = obj->nchains;
1227 else if (obj->valid_hash_gnu) {
1228 obj->dynsymcount = 0;
1229 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1230 if (obj->buckets_gnu[bkt] == 0)
1232 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1235 while ((*hashval++ & 1u) == 0);
1237 obj->dynsymcount += obj->symndx_gnu;
1242 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1243 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1246 if (obj->z_origin && obj->origin_path == NULL) {
1247 obj->origin_path = xmalloc(PATH_MAX);
1248 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1252 if (dyn_runpath != NULL) {
1253 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1255 obj->runpath = origin_subst(obj->runpath, obj->origin_path);
1257 else if (dyn_rpath != NULL) {
1258 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1260 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1263 if (dyn_soname != NULL)
1264 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1268 digest_dynamic(Obj_Entry *obj, int early)
1270 const Elf_Dyn *dyn_rpath;
1271 const Elf_Dyn *dyn_soname;
1272 const Elf_Dyn *dyn_runpath;
1274 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1275 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1279 * Process a shared object's program header. This is used only for the
1280 * main program, when the kernel has already loaded the main program
1281 * into memory before calling the dynamic linker. It creates and
1282 * returns an Obj_Entry structure.
1285 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1288 const Elf_Phdr *phlimit = phdr + phnum;
1290 Elf_Addr note_start, note_end;
1294 for (ph = phdr; ph < phlimit; ph++) {
1295 if (ph->p_type != PT_PHDR)
1299 obj->phsize = ph->p_memsz;
1300 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1304 obj->stack_flags = PF_X | PF_R | PF_W;
1306 for (ph = phdr; ph < phlimit; ph++) {
1307 switch (ph->p_type) {
1310 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1314 if (nsegs == 0) { /* First load segment */
1315 obj->vaddrbase = trunc_page(ph->p_vaddr);
1316 obj->mapbase = obj->vaddrbase + obj->relocbase;
1317 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1319 } else { /* Last load segment */
1320 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1327 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1332 obj->tlssize = ph->p_memsz;
1333 obj->tlsalign = ph->p_align;
1334 obj->tlsinitsize = ph->p_filesz;
1335 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1339 obj->stack_flags = ph->p_flags;
1343 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1344 obj->relro_size = round_page(ph->p_memsz);
1348 obj->note_present = true;
1349 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1350 note_end = note_start + ph->p_filesz;
1351 digest_notes(obj, note_start, note_end);
1356 _rtld_error("%s: too few PT_LOAD segments", path);
1365 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1367 const Elf_Note *note;
1368 const char *note_name;
1371 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1372 note = (const Elf_Note *)((const char *)(note + 1) +
1373 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1374 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1375 if (note->n_namesz != sizeof(NOTE_VENDOR) ||
1376 note->n_descsz != sizeof(int32_t))
1378 if (note->n_type != ABI_NOTETYPE &&
1379 note->n_type != CRT_NOINIT_NOTETYPE)
1381 note_name = (const char *)(note + 1);
1382 if (strncmp(NOTE_VENDOR, note_name, sizeof(NOTE_VENDOR)) != 0)
1384 switch (note->n_type) {
1386 /* DragonFly osrel note */
1387 p = (uintptr_t)(note + 1);
1388 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1389 obj->osrel = *(const int32_t *)(p);
1390 dbg("note osrel %d", obj->osrel);
1392 case CRT_NOINIT_NOTETYPE:
1393 /* DragonFly 'crt does not call init' note */
1394 obj->crt_no_init = true;
1395 dbg("note crt_no_init");
1402 dlcheck(void *handle)
1406 for (obj = obj_list; obj != NULL; obj = obj->next)
1407 if (obj == (Obj_Entry *) handle)
1410 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1411 _rtld_error("Invalid shared object handle %p", handle);
1418 * If the given object is already in the donelist, return true. Otherwise
1419 * add the object to the list and return false.
1422 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1426 for (i = 0; i < dlp->num_used; i++)
1427 if (dlp->objs[i] == obj)
1430 * Our donelist allocation should always be sufficient. But if
1431 * our threads locking isn't working properly, more shared objects
1432 * could have been loaded since we allocated the list. That should
1433 * never happen, but we'll handle it properly just in case it does.
1435 if (dlp->num_used < dlp->num_alloc)
1436 dlp->objs[dlp->num_used++] = obj;
1441 * Hash function for symbol table lookup. Don't even think about changing
1442 * this. It is specified by the System V ABI.
1445 elf_hash(const char *name)
1447 const unsigned char *p = (const unsigned char *) name;
1448 unsigned long h = 0;
1451 while (*p != '\0') {
1452 h = (h << 4) + *p++;
1453 if ((g = h & 0xf0000000) != 0)
1461 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1462 * unsigned in case it's implemented with a wider type.
1464 static uint_fast32_t
1465 gnu_hash(const char *s)
1471 for (c = *s; c != '\0'; c = *++s)
1473 return (h & 0xffffffff);
1477 * Find the library with the given name, and return its full pathname.
1478 * The returned string is dynamically allocated. Generates an error
1479 * message and returns NULL if the library cannot be found.
1481 * If the second argument is non-NULL, then it refers to an already-
1482 * loaded shared object, whose library search path will be searched.
1484 * The search order is:
1485 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1486 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1488 * DT_RUNPATH in the referencing file
1489 * ldconfig hints (if -z nodefaultlib, filter out /usr/lib from list)
1490 * /usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1492 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1495 find_library(const char *xname, const Obj_Entry *refobj)
1499 bool nodeflib, objgiven;
1501 objgiven = refobj != NULL;
1502 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1503 if (xname[0] != '/' && !trust) {
1504 _rtld_error("Absolute pathname required for shared object \"%s\"",
1508 if (objgiven && refobj->z_origin) {
1509 return (origin_subst(__DECONST(char *, xname),
1510 refobj->origin_path));
1512 return (xstrdup(xname));
1516 if (libmap_disable || !objgiven ||
1517 (name = lm_find(refobj->path, xname)) == NULL)
1518 name = (char *)xname;
1520 dbg(" Searching for \"%s\"", name);
1522 nodeflib = objgiven ? refobj->z_nodeflib : false;
1524 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1525 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1526 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1527 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1529 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1530 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1531 (objgiven && !nodeflib &&
1532 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1535 if (objgiven && refobj->path != NULL) {
1536 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1537 name, basename(refobj->path));
1539 _rtld_error("Shared object \"%s\" not found", name);
1545 * Given a symbol number in a referencing object, find the corresponding
1546 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1547 * no definition was found. Returns a pointer to the Obj_Entry of the
1548 * defining object via the reference parameter DEFOBJ_OUT.
1551 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1552 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1553 RtldLockState *lockstate)
1557 const Obj_Entry *defobj;
1563 * If we have already found this symbol, get the information from
1566 if (symnum >= refobj->dynsymcount)
1567 return NULL; /* Bad object */
1568 if (cache != NULL && cache[symnum].sym != NULL) {
1569 *defobj_out = cache[symnum].obj;
1570 return cache[symnum].sym;
1573 ref = refobj->symtab + symnum;
1574 name = refobj->strtab + ref->st_name;
1579 * We don't have to do a full scale lookup if the symbol is local.
1580 * We know it will bind to the instance in this load module; to
1581 * which we already have a pointer (ie ref). By not doing a lookup,
1582 * we not only improve performance, but it also avoids unresolvable
1583 * symbols when local symbols are not in the hash table.
1585 * This might occur for TLS module relocations, which simply use
1588 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1589 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1590 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1593 symlook_init(&req, name);
1595 req.ventry = fetch_ventry(refobj, symnum);
1596 req.lockstate = lockstate;
1597 res = symlook_default(&req, refobj);
1600 defobj = req.defobj_out;
1608 * If we found no definition and the reference is weak, treat the
1609 * symbol as having the value zero.
1611 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1617 *defobj_out = defobj;
1618 /* Record the information in the cache to avoid subsequent lookups. */
1619 if (cache != NULL) {
1620 cache[symnum].sym = def;
1621 cache[symnum].obj = defobj;
1624 if (refobj != &obj_rtld)
1625 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1631 * Return the search path from the ldconfig hints file, reading it if
1632 * necessary. If nostdlib is true, then the default search paths are
1633 * not added to result.
1635 * Returns NULL if there are problems with the hints file,
1636 * or if the search path there is empty.
1639 gethints(bool nostdlib)
1641 static char *hints, *filtered_path;
1642 struct elfhints_hdr hdr;
1643 struct fill_search_info_args sargs, hargs;
1644 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1645 struct dl_serpath *SLPpath, *hintpath;
1647 unsigned int SLPndx, hintndx, fndx, fcount;
1652 /* First call, read the hints file */
1653 if (hints == NULL) {
1654 /* Keep from trying again in case the hints file is bad. */
1657 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1659 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1660 hdr.magic != ELFHINTS_MAGIC ||
1665 p = xmalloc(hdr.dirlistlen + 1);
1666 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1667 read(fd, p, hdr.dirlistlen + 1) !=
1668 (ssize_t)hdr.dirlistlen + 1) {
1678 * If caller agreed to receive list which includes the default
1679 * paths, we are done. Otherwise, if we still have not
1680 * calculated filtered result, do it now.
1683 return (hints[0] != '\0' ? hints : NULL);
1684 if (filtered_path != NULL)
1688 * Obtain the list of all configured search paths, and the
1689 * list of the default paths.
1691 * First estimate the size of the results.
1693 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1695 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1698 sargs.request = RTLD_DI_SERINFOSIZE;
1699 sargs.serinfo = &smeta;
1700 hargs.request = RTLD_DI_SERINFOSIZE;
1701 hargs.serinfo = &hmeta;
1703 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1704 path_enumerate(p, fill_search_info, &hargs);
1706 SLPinfo = xmalloc(smeta.dls_size);
1707 hintinfo = xmalloc(hmeta.dls_size);
1710 * Next fetch both sets of paths.
1712 sargs.request = RTLD_DI_SERINFO;
1713 sargs.serinfo = SLPinfo;
1714 sargs.serpath = &SLPinfo->dls_serpath[0];
1715 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1717 hargs.request = RTLD_DI_SERINFO;
1718 hargs.serinfo = hintinfo;
1719 hargs.serpath = &hintinfo->dls_serpath[0];
1720 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1722 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1723 path_enumerate(p, fill_search_info, &hargs);
1726 * Now calculate the difference between two sets, by excluding
1727 * standard paths from the full set.
1731 filtered_path = xmalloc(hdr.dirlistlen + 1);
1732 hintpath = &hintinfo->dls_serpath[0];
1733 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1735 SLPpath = &SLPinfo->dls_serpath[0];
1737 * Check each standard path against current.
1739 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1740 /* matched, skip the path */
1741 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1749 * Not matched against any standard path, add the path
1750 * to result. Separate consecutive paths with ':'.
1753 filtered_path[fndx] = ':';
1757 flen = strlen(hintpath->dls_name);
1758 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1761 filtered_path[fndx] = '\0';
1767 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1771 init_dag(Obj_Entry *root)
1773 const Needed_Entry *needed;
1774 const Objlist_Entry *elm;
1777 if (root->dag_inited)
1779 donelist_init(&donelist);
1781 /* Root object belongs to own DAG. */
1782 objlist_push_tail(&root->dldags, root);
1783 objlist_push_tail(&root->dagmembers, root);
1784 donelist_check(&donelist, root);
1787 * Add dependencies of root object to DAG in breadth order
1788 * by exploiting the fact that each new object get added
1789 * to the tail of the dagmembers list.
1791 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1792 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1793 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1795 objlist_push_tail(&needed->obj->dldags, root);
1796 objlist_push_tail(&root->dagmembers, needed->obj);
1799 root->dag_inited = true;
1803 process_nodelete(Obj_Entry *root)
1805 const Objlist_Entry *elm;
1808 * Walk over object DAG and process every dependent object that
1809 * is marked as DF_1_NODELETE. They need to grow their own DAG,
1810 * which then should have its reference upped separately.
1812 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1813 if (elm->obj != NULL && elm->obj->z_nodelete &&
1814 !elm->obj->ref_nodel) {
1815 dbg("obj %s nodelete", elm->obj->path);
1818 elm->obj->ref_nodel = true;
1824 * Initialize the dynamic linker. The argument is the address at which
1825 * the dynamic linker has been mapped into memory. The primary task of
1826 * this function is to relocate the dynamic linker.
1829 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1831 Obj_Entry objtmp; /* Temporary rtld object */
1832 const Elf_Dyn *dyn_rpath;
1833 const Elf_Dyn *dyn_soname;
1834 const Elf_Dyn *dyn_runpath;
1837 * Conjure up an Obj_Entry structure for the dynamic linker.
1839 * The "path" member can't be initialized yet because string constants
1840 * cannot yet be accessed. Below we will set it correctly.
1842 memset(&objtmp, 0, sizeof(objtmp));
1845 objtmp.mapbase = mapbase;
1847 objtmp.relocbase = mapbase;
1849 if (RTLD_IS_DYNAMIC()) {
1850 objtmp.dynamic = rtld_dynamic(&objtmp);
1851 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1852 assert(objtmp.needed == NULL);
1853 assert(!objtmp.textrel);
1856 * Temporarily put the dynamic linker entry into the object list, so
1857 * that symbols can be found.
1860 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1863 /* Initialize the object list. */
1864 obj_tail = &obj_list;
1866 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1867 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1869 #ifdef ENABLE_OSRELDATE
1870 if (aux_info[AT_OSRELDATE] != NULL)
1871 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1874 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1876 /* Replace the path with a dynamically allocated copy. */
1877 obj_rtld.path = xstrdup(PATH_RTLD);
1879 r_debug.r_brk = r_debug_state;
1880 r_debug.r_state = RT_CONSISTENT;
1884 * Add the init functions from a needed object list (and its recursive
1885 * needed objects) to "list". This is not used directly; it is a helper
1886 * function for initlist_add_objects(). The write lock must be held
1887 * when this function is called.
1890 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1892 /* Recursively process the successor needed objects. */
1893 if (needed->next != NULL)
1894 initlist_add_neededs(needed->next, list);
1896 /* Process the current needed object. */
1897 if (needed->obj != NULL)
1898 initlist_add_objects(needed->obj, &needed->obj->next, list);
1902 * Scan all of the DAGs rooted in the range of objects from "obj" to
1903 * "tail" and add their init functions to "list". This recurses over
1904 * the DAGs and ensure the proper init ordering such that each object's
1905 * needed libraries are initialized before the object itself. At the
1906 * same time, this function adds the objects to the global finalization
1907 * list "list_fini" in the opposite order. The write lock must be
1908 * held when this function is called.
1911 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1914 if (obj->init_scanned || obj->init_done)
1916 obj->init_scanned = true;
1918 /* Recursively process the successor objects. */
1919 if (&obj->next != tail)
1920 initlist_add_objects(obj->next, tail, list);
1922 /* Recursively process the needed objects. */
1923 if (obj->needed != NULL)
1924 initlist_add_neededs(obj->needed, list);
1925 if (obj->needed_filtees != NULL)
1926 initlist_add_neededs(obj->needed_filtees, list);
1927 if (obj->needed_aux_filtees != NULL)
1928 initlist_add_neededs(obj->needed_aux_filtees, list);
1930 /* Add the object to the init list. */
1931 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1932 obj->init_array != (Elf_Addr)NULL)
1933 objlist_push_tail(list, obj);
1935 /* Add the object to the global fini list in the reverse order. */
1936 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1937 && !obj->on_fini_list) {
1938 objlist_push_head(&list_fini, obj);
1939 obj->on_fini_list = true;
1944 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1948 free_needed_filtees(Needed_Entry *n)
1950 Needed_Entry *needed, *needed1;
1952 for (needed = n; needed != NULL; needed = needed->next) {
1953 if (needed->obj != NULL) {
1954 dlclose(needed->obj);
1958 for (needed = n; needed != NULL; needed = needed1) {
1959 needed1 = needed->next;
1965 unload_filtees(Obj_Entry *obj)
1968 free_needed_filtees(obj->needed_filtees);
1969 obj->needed_filtees = NULL;
1970 free_needed_filtees(obj->needed_aux_filtees);
1971 obj->needed_aux_filtees = NULL;
1972 obj->filtees_loaded = false;
1976 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
1977 RtldLockState *lockstate)
1980 for (; needed != NULL; needed = needed->next) {
1981 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
1982 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
1983 RTLD_LOCAL, lockstate);
1988 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
1991 lock_restart_for_upgrade(lockstate);
1992 if (!obj->filtees_loaded) {
1993 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
1994 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
1995 obj->filtees_loaded = true;
2000 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2004 for (; needed != NULL; needed = needed->next) {
2005 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2006 flags & ~RTLD_LO_NOLOAD);
2007 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2014 * Given a shared object, traverse its list of needed objects, and load
2015 * each of them. Returns 0 on success. Generates an error message and
2016 * returns -1 on failure.
2019 load_needed_objects(Obj_Entry *first, int flags)
2023 for (obj = first; obj != NULL; obj = obj->next) {
2024 if (process_needed(obj, obj->needed, flags) == -1)
2031 load_preload_objects(void)
2033 char *p = ld_preload;
2034 static const char delim[] = " \t:;";
2039 p += strspn(p, delim);
2040 while (*p != '\0') {
2041 size_t len = strcspn(p, delim);
2049 obj = load_object(p, -1, NULL, 0);
2051 return -1; /* XXX - cleanup */
2054 p += strspn(p, delim);
2056 /* Check for the magic tracing function */
2057 symlook_init(&req, RTLD_FUNCTRACE);
2058 res = symlook_obj(&req, obj);
2060 rtld_functrace = (void *)(req.defobj_out->relocbase +
2061 req.sym_out->st_value);
2062 rtld_functrace_obj = req.defobj_out;
2065 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2070 printable_path(const char *path)
2073 return (path == NULL ? "<unknown>" : path);
2077 * Load a shared object into memory, if it is not already loaded. The
2078 * object may be specified by name or by user-supplied file descriptor
2079 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2082 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2086 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2094 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2095 if (object_match_name(obj, name))
2099 path = find_library(name, refobj);
2106 * If we didn't find a match by pathname, or the name is not
2107 * supplied, open the file and check again by device and inode.
2108 * This avoids false mismatches caused by multiple links or ".."
2111 * To avoid a race, we open the file and use fstat() rather than
2116 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) {
2117 _rtld_error("Cannot open \"%s\"", path);
2122 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2125 * Temporary, remove at 3.6 branch
2126 * User might not have latest kernel installed
2127 * so fall back to old command for a while
2130 if (fd == -1 || (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)) {
2131 _rtld_error("Cannot dup fd");
2137 if (fstat(fd, &sb) == -1) {
2138 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2143 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2144 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2146 if (obj != NULL && name != NULL) {
2147 object_add_name(obj, name);
2152 if (flags & RTLD_LO_NOLOAD) {
2158 /* First use of this object, so we must map it in */
2159 obj = do_load_object(fd, name, path, &sb, flags);
2168 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2175 * but first, make sure that environment variables haven't been
2176 * used to circumvent the noexec flag on a filesystem.
2178 if (dangerous_ld_env) {
2179 if (fstatfs(fd, &fs) != 0) {
2180 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2183 if (fs.f_flags & MNT_NOEXEC) {
2184 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2188 dbg("loading \"%s\"", printable_path(path));
2189 obj = map_object(fd, printable_path(path), sbp);
2194 * If DT_SONAME is present in the object, digest_dynamic2 already
2195 * added it to the object names.
2198 object_add_name(obj, name);
2200 digest_dynamic(obj, 0);
2201 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2202 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2203 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2205 dbg("refusing to load non-loadable \"%s\"", obj->path);
2206 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2207 munmap(obj->mapbase, obj->mapsize);
2213 obj_tail = &obj->next;
2216 linkmap_add(obj); /* for GDB & dlinfo() */
2217 max_stack_flags |= obj->stack_flags;
2219 dbg(" %p .. %p: %s", obj->mapbase,
2220 obj->mapbase + obj->mapsize - 1, obj->path);
2222 dbg(" WARNING: %s has impure text", obj->path);
2223 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2230 obj_from_addr(const void *addr)
2234 for (obj = obj_list; obj != NULL; obj = obj->next) {
2235 if (addr < (void *) obj->mapbase)
2237 if (addr < (void *) (obj->mapbase + obj->mapsize))
2244 * If the main program is defined with a .preinit_array section, call
2245 * each function in order. This must occur before the initialization
2246 * of any shared object or the main program.
2251 Elf_Addr *preinit_addr;
2254 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2255 if (preinit_addr == NULL)
2258 for (index = 0; index < obj_main->preinit_array_num; index++) {
2259 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2260 dbg("calling preinit function for %s at %p", obj_main->path,
2261 (void *)preinit_addr[index]);
2262 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2263 0, 0, obj_main->path);
2264 call_init_pointer(obj_main, preinit_addr[index]);
2270 * Call the finalization functions for each of the objects in "list"
2271 * belonging to the DAG of "root" and referenced once. If NULL "root"
2272 * is specified, every finalization function will be called regardless
2273 * of the reference count and the list elements won't be freed. All of
2274 * the objects are expected to have non-NULL fini functions.
2277 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2281 Elf_Addr *fini_addr;
2284 assert(root == NULL || root->refcount == 1);
2287 * Preserve the current error message since a fini function might
2288 * call into the dynamic linker and overwrite it.
2290 saved_msg = errmsg_save();
2292 STAILQ_FOREACH(elm, list, link) {
2293 if (root != NULL && (elm->obj->refcount != 1 ||
2294 objlist_find(&root->dagmembers, elm->obj) == NULL))
2297 /* Remove object from fini list to prevent recursive invocation. */
2298 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2300 * XXX: If a dlopen() call references an object while the
2301 * fini function is in progress, we might end up trying to
2302 * unload the referenced object in dlclose() or the object
2303 * won't be unloaded although its fini function has been
2306 lock_release(rtld_bind_lock, lockstate);
2309 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. When this
2310 * happens, DT_FINI_ARRAY is processed first, and it is also processed
2311 * backwards. It is possible to encounter DT_FINI_ARRAY elements with
2312 * values of 0 or 1, but they need to be ignored.
2314 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2315 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2316 for (index = elm->obj->fini_array_num - 1; index >= 0; index--) {
2317 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2318 dbg("calling fini array function for %s at %p",
2319 elm->obj->path, (void *)fini_addr[index]);
2320 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2321 (void *)fini_addr[index], 0, 0, elm->obj->path);
2322 call_initfini_pointer(elm->obj, fini_addr[index]);
2326 if (elm->obj->fini != (Elf_Addr)NULL) {
2327 dbg("calling fini function for %s at %p", elm->obj->path,
2328 (void *)elm->obj->fini);
2329 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2330 0, 0, elm->obj->path);
2331 call_initfini_pointer(elm->obj, elm->obj->fini);
2333 wlock_acquire(rtld_bind_lock, lockstate);
2334 /* No need to free anything if process is going down. */
2338 * We must restart the list traversal after every fini call
2339 * because a dlclose() call from the fini function or from
2340 * another thread might have modified the reference counts.
2344 } while (elm != NULL);
2345 errmsg_restore(saved_msg);
2349 * Call the initialization functions for each of the objects in
2350 * "list". All of the objects are expected to have non-NULL init
2354 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2359 Elf_Addr *init_addr;
2363 * Clean init_scanned flag so that objects can be rechecked and
2364 * possibly initialized earlier if any of vectors called below
2365 * cause the change by using dlopen.
2367 for (obj = obj_list; obj != NULL; obj = obj->next)
2368 obj->init_scanned = false;
2371 * Preserve the current error message since an init function might
2372 * call into the dynamic linker and overwrite it.
2374 saved_msg = errmsg_save();
2375 STAILQ_FOREACH(elm, list, link) {
2376 if (elm->obj->init_done) /* Initialized early. */
2380 * Race: other thread might try to use this object before current
2381 * one completes the initilization. Not much can be done here
2382 * without better locking.
2384 elm->obj->init_done = true;
2385 lock_release(rtld_bind_lock, lockstate);
2388 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. When
2389 * this happens, DT_INIT is processed first. It is possible to
2390 * encounter DT_INIT_ARRAY elements with values of 0 or 1, but they
2391 * need to be ignored.
2393 if (elm->obj->init != (Elf_Addr)NULL) {
2394 dbg("calling init function for %s at %p", elm->obj->path,
2395 (void *)elm->obj->init);
2396 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2397 0, 0, elm->obj->path);
2398 call_initfini_pointer(elm->obj, elm->obj->init);
2400 init_addr = (Elf_Addr *)elm->obj->init_array;
2401 if (init_addr != NULL) {
2402 for (index = 0; index < elm->obj->init_array_num; index++) {
2403 if (init_addr[index] != 0 && init_addr[index] != 1) {
2404 dbg("calling init array function for %s at %p", elm->obj->path,
2405 (void *)init_addr[index]);
2406 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2407 (void *)init_addr[index], 0, 0, elm->obj->path);
2408 call_init_pointer(elm->obj, init_addr[index]);
2412 wlock_acquire(rtld_bind_lock, lockstate);
2414 errmsg_restore(saved_msg);
2418 objlist_clear(Objlist *list)
2422 while (!STAILQ_EMPTY(list)) {
2423 elm = STAILQ_FIRST(list);
2424 STAILQ_REMOVE_HEAD(list, link);
2429 static Objlist_Entry *
2430 objlist_find(Objlist *list, const Obj_Entry *obj)
2434 STAILQ_FOREACH(elm, list, link)
2435 if (elm->obj == obj)
2441 objlist_init(Objlist *list)
2447 objlist_push_head(Objlist *list, Obj_Entry *obj)
2451 elm = NEW(Objlist_Entry);
2453 STAILQ_INSERT_HEAD(list, elm, link);
2457 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2461 elm = NEW(Objlist_Entry);
2463 STAILQ_INSERT_TAIL(list, elm, link);
2467 objlist_remove(Objlist *list, Obj_Entry *obj)
2471 if ((elm = objlist_find(list, obj)) != NULL) {
2472 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2478 * Relocate dag rooted in the specified object.
2479 * Returns 0 on success, or -1 on failure.
2483 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2484 int flags, RtldLockState *lockstate)
2490 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2491 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2500 * Relocate single object.
2501 * Returns 0 on success, or -1 on failure.
2504 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2505 int flags, RtldLockState *lockstate)
2510 obj->relocated = true;
2512 dbg("relocating \"%s\"", obj->path);
2514 if (obj->symtab == NULL || obj->strtab == NULL ||
2515 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2516 _rtld_error("%s: Shared object has no run-time symbol table",
2522 /* There are relocations to the write-protected text segment. */
2523 if (mprotect(obj->mapbase, obj->textsize,
2524 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2525 _rtld_error("%s: Cannot write-enable text segment: %s",
2526 obj->path, rtld_strerror(errno));
2531 /* Process the non-PLT relocations. */
2532 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2536 * Reprotect the text segment. Make sure it is included in the
2537 * core dump since we modified it. This unfortunately causes the
2538 * entire text segment to core-out but we don't have much of a
2539 * choice. We could try to only reenable core dumps on pages
2540 * in which relocations occured but that is likely most of the text
2541 * pages anyway, and even that would not work because the rest of
2542 * the text pages would wind up as a read-only OBJT_DEFAULT object
2543 * (created due to our modifications) backed by the original OBJT_VNODE
2544 * object, and the ELF coredump code is currently only able to dump
2545 * vnode records for pure vnode-backed mappings, not vnode backings
2546 * to memory objects.
2549 madvise(obj->mapbase, obj->textsize, MADV_CORE);
2550 if (mprotect(obj->mapbase, obj->textsize,
2551 PROT_READ|PROT_EXEC) == -1) {
2552 _rtld_error("%s: Cannot write-protect text segment: %s",
2553 obj->path, rtld_strerror(errno));
2559 /* Set the special PLT or GOT entries. */
2562 /* Process the PLT relocations. */
2563 if (reloc_plt(obj) == -1)
2565 /* Relocate the jump slots if we are doing immediate binding. */
2566 if (obj->bind_now || bind_now)
2567 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2571 * Set up the magic number and version in the Obj_Entry. These
2572 * were checked in the crt1.o from the original ElfKit, so we
2573 * set them for backward compatibility.
2575 obj->magic = RTLD_MAGIC;
2576 obj->version = RTLD_VERSION;
2579 * Set relocated data to read-only status if protection specified
2582 if (obj->relro_size) {
2583 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) {
2584 _rtld_error("%s: Cannot enforce relro relocation: %s",
2585 obj->path, rtld_strerror(errno));
2593 * Relocate newly-loaded shared objects. The argument is a pointer to
2594 * the Obj_Entry for the first such object. All objects from the first
2595 * to the end of the list of objects are relocated. Returns 0 on success,
2599 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2600 int flags, RtldLockState *lockstate)
2605 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2606 error = relocate_object(obj, bind_now, rtldobj, flags,
2615 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2616 * referencing STT_GNU_IFUNC symbols is postponed till the other
2617 * relocations are done. The indirect functions specified as
2618 * ifunc are allowed to call other symbols, so we need to have
2619 * objects relocated before asking for resolution from indirects.
2621 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2622 * instead of the usual lazy handling of PLT slots. It is
2623 * consistent with how GNU does it.
2626 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2627 RtldLockState *lockstate)
2629 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2631 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2632 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2638 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2639 RtldLockState *lockstate)
2643 for (obj = first; obj != NULL; obj = obj->next) {
2644 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2651 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2652 RtldLockState *lockstate)
2656 STAILQ_FOREACH(elm, list, link) {
2657 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2665 * Cleanup procedure. It will be called (by the atexit mechanism) just
2666 * before the process exits.
2671 RtldLockState lockstate;
2673 wlock_acquire(rtld_bind_lock, &lockstate);
2675 objlist_call_fini(&list_fini, NULL, &lockstate);
2676 /* No need to remove the items from the list, since we are exiting. */
2677 if (!libmap_disable)
2679 lock_release(rtld_bind_lock, &lockstate);
2683 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2688 path += strspn(path, ":;");
2689 while (*path != '\0') {
2693 len = strcspn(path, ":;");
2694 res = callback(path, len, arg);
2700 path += strspn(path, ":;");
2706 struct try_library_args {
2714 try_library_path(const char *dir, size_t dirlen, void *param)
2716 struct try_library_args *arg;
2719 if (*dir == '/' || trust) {
2722 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2725 pathname = arg->buffer;
2726 strncpy(pathname, dir, dirlen);
2727 pathname[dirlen] = '/';
2728 strcpy(pathname + dirlen + 1, arg->name);
2730 dbg(" Trying \"%s\"", pathname);
2731 if (access(pathname, F_OK) == 0) { /* We found it */
2732 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2733 strcpy(pathname, arg->buffer);
2741 search_library_path(const char *name, const char *path)
2744 struct try_library_args arg;
2750 arg.namelen = strlen(name);
2751 arg.buffer = xmalloc(PATH_MAX);
2752 arg.buflen = PATH_MAX;
2754 p = path_enumerate(path, try_library_path, &arg);
2762 dlclose(void *handle)
2765 RtldLockState lockstate;
2767 wlock_acquire(rtld_bind_lock, &lockstate);
2768 root = dlcheck(handle);
2770 lock_release(rtld_bind_lock, &lockstate);
2773 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2776 /* Unreference the object and its dependencies. */
2777 root->dl_refcount--;
2779 if (root->refcount == 1) {
2781 * The object will be no longer referenced, so we must unload it.
2782 * First, call the fini functions.
2784 objlist_call_fini(&list_fini, root, &lockstate);
2788 /* Finish cleaning up the newly-unreferenced objects. */
2789 GDB_STATE(RT_DELETE,&root->linkmap);
2790 unload_object(root);
2791 GDB_STATE(RT_CONSISTENT,NULL);
2795 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2796 lock_release(rtld_bind_lock, &lockstate);
2803 char *msg = error_message;
2804 error_message = NULL;
2809 dlopen(const char *name, int mode)
2812 return (rtld_dlopen(name, -1, mode));
2816 fdlopen(int fd, int mode)
2819 return (rtld_dlopen(NULL, fd, mode));
2823 rtld_dlopen(const char *name, int fd, int mode)
2825 RtldLockState lockstate;
2828 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2829 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2830 if (ld_tracing != NULL) {
2831 rlock_acquire(rtld_bind_lock, &lockstate);
2832 if (sigsetjmp(lockstate.env, 0) != 0)
2833 lock_upgrade(rtld_bind_lock, &lockstate);
2834 environ = (char **)*get_program_var_addr("environ", &lockstate);
2835 lock_release(rtld_bind_lock, &lockstate);
2837 lo_flags = RTLD_LO_DLOPEN;
2838 if (mode & RTLD_NODELETE)
2839 lo_flags |= RTLD_LO_NODELETE;
2840 if (mode & RTLD_NOLOAD)
2841 lo_flags |= RTLD_LO_NOLOAD;
2842 if (ld_tracing != NULL)
2843 lo_flags |= RTLD_LO_TRACE;
2845 return (dlopen_object(name, fd, obj_main, lo_flags,
2846 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
2850 dlopen_cleanup(Obj_Entry *obj)
2855 if (obj->refcount == 0)
2860 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2861 int mode, RtldLockState *lockstate)
2863 Obj_Entry **old_obj_tail;
2866 RtldLockState mlockstate;
2869 objlist_init(&initlist);
2871 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
2872 wlock_acquire(rtld_bind_lock, &mlockstate);
2873 lockstate = &mlockstate;
2875 GDB_STATE(RT_ADD,NULL);
2877 old_obj_tail = obj_tail;
2879 if (name == NULL && fd == -1) {
2883 obj = load_object(name, fd, refobj, lo_flags);
2888 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2889 objlist_push_tail(&list_global, obj);
2890 if (*old_obj_tail != NULL) { /* We loaded something new. */
2891 assert(*old_obj_tail == obj);
2892 result = load_needed_objects(obj,
2893 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
2897 result = rtld_verify_versions(&obj->dagmembers);
2898 if (result != -1 && ld_tracing)
2900 if (result == -1 || relocate_object_dag(obj,
2901 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
2902 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2904 dlopen_cleanup(obj);
2906 } else if (lo_flags & RTLD_LO_EARLY) {
2908 * Do not call the init functions for early loaded
2909 * filtees. The image is still not initialized enough
2912 * Our object is found by the global object list and
2913 * will be ordered among all init calls done right
2914 * before transferring control to main.
2917 /* Make list of init functions to call. */
2918 initlist_add_objects(obj, &obj->next, &initlist);
2921 * Process all no_delete objects here, given them own
2922 * DAGs to prevent their dependencies from being unloaded.
2923 * This has to be done after we have loaded all of the
2924 * dependencies, so that we do not miss any.
2927 process_nodelete(obj);
2930 * Bump the reference counts for objects on this DAG. If
2931 * this is the first dlopen() call for the object that was
2932 * already loaded as a dependency, initialize the dag
2938 if ((lo_flags & RTLD_LO_TRACE) != 0)
2941 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2942 obj->z_nodelete) && !obj->ref_nodel) {
2943 dbg("obj %s nodelete", obj->path);
2945 obj->z_nodelete = obj->ref_nodel = true;
2949 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2951 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2953 if (!(lo_flags & RTLD_LO_EARLY)) {
2954 map_stacks_exec(lockstate);
2957 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
2958 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2960 objlist_clear(&initlist);
2961 dlopen_cleanup(obj);
2962 if (lockstate == &mlockstate)
2963 lock_release(rtld_bind_lock, lockstate);
2967 if (!(lo_flags & RTLD_LO_EARLY)) {
2968 /* Call the init functions. */
2969 objlist_call_init(&initlist, lockstate);
2971 objlist_clear(&initlist);
2972 if (lockstate == &mlockstate)
2973 lock_release(rtld_bind_lock, lockstate);
2976 trace_loaded_objects(obj);
2977 if (lockstate == &mlockstate)
2978 lock_release(rtld_bind_lock, lockstate);
2983 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
2987 const Obj_Entry *obj, *defobj;
2990 RtldLockState lockstate;
2996 symlook_init(&req, name);
2998 req.flags = flags | SYMLOOK_IN_PLT;
2999 req.lockstate = &lockstate;
3001 rlock_acquire(rtld_bind_lock, &lockstate);
3002 if (sigsetjmp(lockstate.env, 0) != 0)
3003 lock_upgrade(rtld_bind_lock, &lockstate);
3004 if (handle == NULL || handle == RTLD_NEXT ||
3005 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3007 if ((obj = obj_from_addr(retaddr)) == NULL) {
3008 _rtld_error("Cannot determine caller's shared object");
3009 lock_release(rtld_bind_lock, &lockstate);
3012 if (handle == NULL) { /* Just the caller's shared object. */
3013 res = symlook_obj(&req, obj);
3016 defobj = req.defobj_out;
3018 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3019 handle == RTLD_SELF) { /* ... caller included */
3020 if (handle == RTLD_NEXT)
3022 for (; obj != NULL; obj = obj->next) {
3023 res = symlook_obj(&req, obj);
3026 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3028 defobj = req.defobj_out;
3029 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3035 * Search the dynamic linker itself, and possibly resolve the
3036 * symbol from there. This is how the application links to
3037 * dynamic linker services such as dlopen.
3039 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3040 res = symlook_obj(&req, &obj_rtld);
3043 defobj = req.defobj_out;
3047 assert(handle == RTLD_DEFAULT);
3048 res = symlook_default(&req, obj);
3050 defobj = req.defobj_out;
3055 if ((obj = dlcheck(handle)) == NULL) {
3056 lock_release(rtld_bind_lock, &lockstate);
3060 donelist_init(&donelist);
3061 if (obj->mainprog) {
3062 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3063 res = symlook_global(&req, &donelist);
3066 defobj = req.defobj_out;
3069 * Search the dynamic linker itself, and possibly resolve the
3070 * symbol from there. This is how the application links to
3071 * dynamic linker services such as dlopen.
3073 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3074 res = symlook_obj(&req, &obj_rtld);
3077 defobj = req.defobj_out;
3082 /* Search the whole DAG rooted at the given object. */
3083 res = symlook_list(&req, &obj->dagmembers, &donelist);
3086 defobj = req.defobj_out;
3092 lock_release(rtld_bind_lock, &lockstate);
3095 * The value required by the caller is derived from the value
3096 * of the symbol. For the ia64 architecture, we need to
3097 * construct a function descriptor which the caller can use to
3098 * call the function with the right 'gp' value. For other
3099 * architectures and for non-functions, the value is simply
3100 * the relocated value of the symbol.
3102 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3103 return (make_function_pointer(def, defobj));
3104 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3105 return (rtld_resolve_ifunc(defobj, def));
3106 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3107 ti.ti_module = defobj->tlsindex;
3108 ti.ti_offset = def->st_value;
3109 return (__tls_get_addr(&ti));
3111 return (defobj->relocbase + def->st_value);
3114 _rtld_error("Undefined symbol \"%s\"", name);
3115 lock_release(rtld_bind_lock, &lockstate);
3120 dlsym(void *handle, const char *name)
3122 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3127 dlfunc(void *handle, const char *name)
3134 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3140 dlvsym(void *handle, const char *name, const char *version)
3144 ventry.name = version;
3146 ventry.hash = elf_hash(version);
3148 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3153 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3155 const Obj_Entry *obj;
3156 RtldLockState lockstate;
3158 rlock_acquire(rtld_bind_lock, &lockstate);
3159 obj = obj_from_addr(addr);
3161 _rtld_error("No shared object contains address");
3162 lock_release(rtld_bind_lock, &lockstate);
3165 rtld_fill_dl_phdr_info(obj, phdr_info);
3166 lock_release(rtld_bind_lock, &lockstate);
3171 dladdr(const void *addr, Dl_info *info)
3173 const Obj_Entry *obj;
3176 unsigned long symoffset;
3177 RtldLockState lockstate;
3179 rlock_acquire(rtld_bind_lock, &lockstate);
3180 obj = obj_from_addr(addr);
3182 _rtld_error("No shared object contains address");
3183 lock_release(rtld_bind_lock, &lockstate);
3186 info->dli_fname = obj->path;
3187 info->dli_fbase = obj->mapbase;
3188 info->dli_saddr = NULL;
3189 info->dli_sname = NULL;
3192 * Walk the symbol list looking for the symbol whose address is
3193 * closest to the address sent in.
3195 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3196 def = obj->symtab + symoffset;
3199 * For skip the symbol if st_shndx is either SHN_UNDEF or
3202 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3206 * If the symbol is greater than the specified address, or if it
3207 * is further away from addr than the current nearest symbol,
3210 symbol_addr = obj->relocbase + def->st_value;
3211 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3214 /* Update our idea of the nearest symbol. */
3215 info->dli_sname = obj->strtab + def->st_name;
3216 info->dli_saddr = symbol_addr;
3219 if (info->dli_saddr == addr)
3222 lock_release(rtld_bind_lock, &lockstate);
3227 dlinfo(void *handle, int request, void *p)
3229 const Obj_Entry *obj;
3230 RtldLockState lockstate;
3233 rlock_acquire(rtld_bind_lock, &lockstate);
3235 if (handle == NULL || handle == RTLD_SELF) {
3238 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3239 if ((obj = obj_from_addr(retaddr)) == NULL)
3240 _rtld_error("Cannot determine caller's shared object");
3242 obj = dlcheck(handle);
3245 lock_release(rtld_bind_lock, &lockstate);
3251 case RTLD_DI_LINKMAP:
3252 *((struct link_map const **)p) = &obj->linkmap;
3254 case RTLD_DI_ORIGIN:
3255 error = rtld_dirname(obj->path, p);
3258 case RTLD_DI_SERINFOSIZE:
3259 case RTLD_DI_SERINFO:
3260 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3264 _rtld_error("Invalid request %d passed to dlinfo()", request);
3268 lock_release(rtld_bind_lock, &lockstate);
3274 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3277 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3278 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
3279 STAILQ_FIRST(&obj->names)->name : obj->path;
3280 phdr_info->dlpi_phdr = obj->phdr;
3281 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3282 phdr_info->dlpi_tls_modid = obj->tlsindex;
3283 phdr_info->dlpi_tls_data = obj->tlsinit;
3284 phdr_info->dlpi_adds = obj_loads;
3285 phdr_info->dlpi_subs = obj_loads - obj_count;
3289 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3291 struct dl_phdr_info phdr_info;
3292 const Obj_Entry *obj;
3293 RtldLockState bind_lockstate, phdr_lockstate;
3296 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3297 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3301 for (obj = obj_list; obj != NULL; obj = obj->next) {
3302 rtld_fill_dl_phdr_info(obj, &phdr_info);
3303 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3307 lock_release(rtld_bind_lock, &bind_lockstate);
3308 lock_release(rtld_phdr_lock, &phdr_lockstate);
3314 fill_search_info(const char *dir, size_t dirlen, void *param)
3316 struct fill_search_info_args *arg;
3320 if (arg->request == RTLD_DI_SERINFOSIZE) {
3321 arg->serinfo->dls_cnt ++;
3322 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3324 struct dl_serpath *s_entry;
3326 s_entry = arg->serpath;
3327 s_entry->dls_name = arg->strspace;
3328 s_entry->dls_flags = arg->flags;
3330 strncpy(arg->strspace, dir, dirlen);
3331 arg->strspace[dirlen] = '\0';
3333 arg->strspace += dirlen + 1;
3341 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3343 struct dl_serinfo _info;
3344 struct fill_search_info_args args;
3346 args.request = RTLD_DI_SERINFOSIZE;
3347 args.serinfo = &_info;
3349 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3352 path_enumerate(obj->rpath, fill_search_info, &args);
3353 path_enumerate(ld_library_path, fill_search_info, &args);
3354 path_enumerate(obj->runpath, fill_search_info, &args);
3355 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3356 if (!obj->z_nodeflib)
3357 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3360 if (request == RTLD_DI_SERINFOSIZE) {
3361 info->dls_size = _info.dls_size;
3362 info->dls_cnt = _info.dls_cnt;
3366 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3367 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3371 args.request = RTLD_DI_SERINFO;
3372 args.serinfo = info;
3373 args.serpath = &info->dls_serpath[0];
3374 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3376 args.flags = LA_SER_RUNPATH;
3377 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3380 args.flags = LA_SER_LIBPATH;
3381 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3384 args.flags = LA_SER_RUNPATH;
3385 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3388 args.flags = LA_SER_CONFIG;
3389 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3393 args.flags = LA_SER_DEFAULT;
3394 if (!obj->z_nodeflib &&
3395 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3401 rtld_dirname(const char *path, char *bname)
3405 /* Empty or NULL string gets treated as "." */
3406 if (path == NULL || *path == '\0') {
3412 /* Strip trailing slashes */
3413 endp = path + strlen(path) - 1;
3414 while (endp > path && *endp == '/')
3417 /* Find the start of the dir */
3418 while (endp > path && *endp != '/')
3421 /* Either the dir is "/" or there are no slashes */
3423 bname[0] = *endp == '/' ? '/' : '.';
3429 } while (endp > path && *endp == '/');
3432 if (endp - path + 2 > PATH_MAX)
3434 _rtld_error("Filename is too long: %s", path);
3438 strncpy(bname, path, endp - path + 1);
3439 bname[endp - path + 1] = '\0';
3444 rtld_dirname_abs(const char *path, char *base)
3446 char base_rel[PATH_MAX];
3448 if (rtld_dirname(path, base) == -1)
3452 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
3453 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
3454 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
3456 strcpy(base, base_rel);
3461 linkmap_add(Obj_Entry *obj)
3463 struct link_map *l = &obj->linkmap;
3464 struct link_map *prev;
3466 obj->linkmap.l_name = obj->path;
3467 obj->linkmap.l_addr = obj->mapbase;
3468 obj->linkmap.l_ld = obj->dynamic;
3470 /* GDB needs load offset on MIPS to use the symbols */
3471 obj->linkmap.l_offs = obj->relocbase;
3474 if (r_debug.r_map == NULL) {
3480 * Scan to the end of the list, but not past the entry for the
3481 * dynamic linker, which we want to keep at the very end.
3483 for (prev = r_debug.r_map;
3484 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3485 prev = prev->l_next)
3488 /* Link in the new entry. */
3490 l->l_next = prev->l_next;
3491 if (l->l_next != NULL)
3492 l->l_next->l_prev = l;
3497 linkmap_delete(Obj_Entry *obj)
3499 struct link_map *l = &obj->linkmap;
3501 if (l->l_prev == NULL) {
3502 if ((r_debug.r_map = l->l_next) != NULL)
3503 l->l_next->l_prev = NULL;
3507 if ((l->l_prev->l_next = l->l_next) != NULL)
3508 l->l_next->l_prev = l->l_prev;
3512 * Function for the debugger to set a breakpoint on to gain control.
3514 * The two parameters allow the debugger to easily find and determine
3515 * what the runtime loader is doing and to whom it is doing it.
3517 * When the loadhook trap is hit (r_debug_state, set at program
3518 * initialization), the arguments can be found on the stack:
3520 * +8 struct link_map *m
3521 * +4 struct r_debug *rd
3525 r_debug_state(struct r_debug* rd, struct link_map *m)
3528 * The following is a hack to force the compiler to emit calls to
3529 * this function, even when optimizing. If the function is empty,
3530 * the compiler is not obliged to emit any code for calls to it,
3531 * even when marked __noinline. However, gdb depends on those
3534 __asm __volatile("" : : : "memory");
3538 * Get address of the pointer variable in the main program.
3539 * Prefer non-weak symbol over the weak one.
3541 static const void **
3542 get_program_var_addr(const char *name, RtldLockState *lockstate)
3547 symlook_init(&req, name);
3548 req.lockstate = lockstate;
3549 donelist_init(&donelist);
3550 if (symlook_global(&req, &donelist) != 0)
3552 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3553 return ((const void **)make_function_pointer(req.sym_out,
3555 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3556 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3558 return ((const void **)(req.defobj_out->relocbase +
3559 req.sym_out->st_value));
3563 * Set a pointer variable in the main program to the given value. This
3564 * is used to set key variables such as "environ" before any of the
3565 * init functions are called.
3568 set_program_var(const char *name, const void *value)
3572 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3573 dbg("\"%s\": *%p <-- %p", name, addr, value);
3579 * Search the global objects, including dependencies and main object,
3580 * for the given symbol.
3583 symlook_global(SymLook *req, DoneList *donelist)
3586 const Objlist_Entry *elm;
3589 symlook_init_from_req(&req1, req);
3591 /* Search all objects loaded at program start up. */
3592 if (req->defobj_out == NULL ||
3593 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3594 res = symlook_list(&req1, &list_main, donelist);
3595 if (res == 0 && (req->defobj_out == NULL ||
3596 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3597 req->sym_out = req1.sym_out;
3598 req->defobj_out = req1.defobj_out;
3599 assert(req->defobj_out != NULL);
3603 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3604 STAILQ_FOREACH(elm, &list_global, link) {
3605 if (req->defobj_out != NULL &&
3606 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3608 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3609 if (res == 0 && (req->defobj_out == NULL ||
3610 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3611 req->sym_out = req1.sym_out;
3612 req->defobj_out = req1.defobj_out;
3613 assert(req->defobj_out != NULL);
3617 return (req->sym_out != NULL ? 0 : ESRCH);
3621 * This is a special version of getenv which is far more efficient
3622 * at finding LD_ environment vars.
3626 _getenv_ld(const char *id)
3630 int idlen = strlen(id);
3632 if (ld_index == LD_ARY_CACHE)
3634 if (ld_index == 0) {
3635 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) {
3636 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_')
3643 for (i = ld_index - 1; i >= 0; --i) {
3644 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=')
3645 return(ld_ary[i] + idlen + 1);
3651 * Given a symbol name in a referencing object, find the corresponding
3652 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3653 * no definition was found. Returns a pointer to the Obj_Entry of the
3654 * defining object via the reference parameter DEFOBJ_OUT.
3657 symlook_default(SymLook *req, const Obj_Entry *refobj)
3660 const Objlist_Entry *elm;
3664 donelist_init(&donelist);
3665 symlook_init_from_req(&req1, req);
3667 /* Look first in the referencing object if linked symbolically. */
3668 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3669 res = symlook_obj(&req1, refobj);
3671 req->sym_out = req1.sym_out;
3672 req->defobj_out = req1.defobj_out;
3673 assert(req->defobj_out != NULL);
3677 symlook_global(req, &donelist);
3679 /* Search all dlopened DAGs containing the referencing object. */
3680 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3681 if (req->sym_out != NULL &&
3682 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3684 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3685 if (res == 0 && (req->sym_out == NULL ||
3686 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3687 req->sym_out = req1.sym_out;
3688 req->defobj_out = req1.defobj_out;
3689 assert(req->defobj_out != NULL);
3694 * Search the dynamic linker itself, and possibly resolve the
3695 * symbol from there. This is how the application links to
3696 * dynamic linker services such as dlopen.
3698 if (req->sym_out == NULL ||
3699 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3700 res = symlook_obj(&req1, &obj_rtld);
3702 req->sym_out = req1.sym_out;
3703 req->defobj_out = req1.defobj_out;
3704 assert(req->defobj_out != NULL);
3708 return (req->sym_out != NULL ? 0 : ESRCH);
3712 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3715 const Obj_Entry *defobj;
3716 const Objlist_Entry *elm;
3722 STAILQ_FOREACH(elm, objlist, link) {
3723 if (donelist_check(dlp, elm->obj))
3725 symlook_init_from_req(&req1, req);
3726 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3727 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3729 defobj = req1.defobj_out;
3730 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3737 req->defobj_out = defobj;
3744 * Search the chain of DAGS cointed to by the given Needed_Entry
3745 * for a symbol of the given name. Each DAG is scanned completely
3746 * before advancing to the next one. Returns a pointer to the symbol,
3747 * or NULL if no definition was found.
3750 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3753 const Needed_Entry *n;
3754 const Obj_Entry *defobj;
3760 symlook_init_from_req(&req1, req);
3761 for (n = needed; n != NULL; n = n->next) {
3762 if (n->obj == NULL ||
3763 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3765 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3767 defobj = req1.defobj_out;
3768 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3774 req->defobj_out = defobj;
3781 * Search the symbol table of a single shared object for a symbol of
3782 * the given name and version, if requested. Returns a pointer to the
3783 * symbol, or NULL if no definition was found. If the object is
3784 * filter, return filtered symbol from filtee.
3786 * The symbol's hash value is passed in for efficiency reasons; that
3787 * eliminates many recomputations of the hash value.
3790 symlook_obj(SymLook *req, const Obj_Entry *obj)
3794 int flags, res, mres;
3797 * If there is at least one valid hash at this point, we prefer to
3798 * use the faster GNU version if available.
3800 if (obj->valid_hash_gnu)
3801 mres = symlook_obj1_gnu(req, obj);
3802 else if (obj->valid_hash_sysv)
3803 mres = symlook_obj1_sysv(req, obj);
3808 if (obj->needed_filtees != NULL) {
3809 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3810 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3811 donelist_init(&donelist);
3812 symlook_init_from_req(&req1, req);
3813 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3815 req->sym_out = req1.sym_out;
3816 req->defobj_out = req1.defobj_out;
3820 if (obj->needed_aux_filtees != NULL) {
3821 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3822 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3823 donelist_init(&donelist);
3824 symlook_init_from_req(&req1, req);
3825 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3827 req->sym_out = req1.sym_out;
3828 req->defobj_out = req1.defobj_out;
3836 /* Symbol match routine common to both hash functions */
3838 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3839 const unsigned long symnum)
3842 const Elf_Sym *symp;
3845 symp = obj->symtab + symnum;
3846 strp = obj->strtab + symp->st_name;
3848 switch (ELF_ST_TYPE(symp->st_info)) {
3854 if (symp->st_value == 0)
3858 if (symp->st_shndx != SHN_UNDEF)
3860 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3861 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3867 if (strcmp(req->name, strp) != 0)
3870 if (req->ventry == NULL) {
3871 if (obj->versyms != NULL) {
3872 verndx = VER_NDX(obj->versyms[symnum]);
3873 if (verndx > obj->vernum) {
3875 "%s: symbol %s references wrong version %d",
3876 obj->path, obj->strtab + symnum, verndx);
3880 * If we are not called from dlsym (i.e. this
3881 * is a normal relocation from unversioned
3882 * binary), accept the symbol immediately if
3883 * it happens to have first version after this
3884 * shared object became versioned. Otherwise,
3885 * if symbol is versioned and not hidden,
3886 * remember it. If it is the only symbol with
3887 * this name exported by the shared object, it
3888 * will be returned as a match by the calling
3889 * function. If symbol is global (verndx < 2)
3890 * accept it unconditionally.
3892 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3893 verndx == VER_NDX_GIVEN) {
3894 result->sym_out = symp;
3897 else if (verndx >= VER_NDX_GIVEN) {
3898 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
3900 if (result->vsymp == NULL)
3901 result->vsymp = symp;
3907 result->sym_out = symp;
3910 if (obj->versyms == NULL) {
3911 if (object_match_name(obj, req->ventry->name)) {
3912 _rtld_error("%s: object %s should provide version %s "
3913 "for symbol %s", obj_rtld.path, obj->path,
3914 req->ventry->name, obj->strtab + symnum);
3918 verndx = VER_NDX(obj->versyms[symnum]);
3919 if (verndx > obj->vernum) {
3920 _rtld_error("%s: symbol %s references wrong version %d",
3921 obj->path, obj->strtab + symnum, verndx);
3924 if (obj->vertab[verndx].hash != req->ventry->hash ||
3925 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3927 * Version does not match. Look if this is a
3928 * global symbol and if it is not hidden. If
3929 * global symbol (verndx < 2) is available,
3930 * use it. Do not return symbol if we are
3931 * called by dlvsym, because dlvsym looks for
3932 * a specific version and default one is not
3933 * what dlvsym wants.
3935 if ((req->flags & SYMLOOK_DLSYM) ||
3936 (verndx >= VER_NDX_GIVEN) ||
3937 (obj->versyms[symnum] & VER_NDX_HIDDEN))
3941 result->sym_out = symp;
3946 * Search for symbol using SysV hash function.
3947 * obj->buckets is known not to be NULL at this point; the test for this was
3948 * performed with the obj->valid_hash_sysv assignment.
3951 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
3953 unsigned long symnum;
3954 Sym_Match_Result matchres;
3956 matchres.sym_out = NULL;
3957 matchres.vsymp = NULL;
3958 matchres.vcount = 0;
3960 for (symnum = obj->buckets[req->hash % obj->nbuckets];
3961 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
3962 if (symnum >= obj->nchains)
3963 return (ESRCH); /* Bad object */
3965 if (matched_symbol(req, obj, &matchres, symnum)) {
3966 req->sym_out = matchres.sym_out;
3967 req->defobj_out = obj;
3971 if (matchres.vcount == 1) {
3972 req->sym_out = matchres.vsymp;
3973 req->defobj_out = obj;
3979 /* Search for symbol using GNU hash function */
3981 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
3983 Elf_Addr bloom_word;
3984 const Elf32_Word *hashval;
3986 Sym_Match_Result matchres;
3987 unsigned int h1, h2;
3988 unsigned long symnum;
3990 matchres.sym_out = NULL;
3991 matchres.vsymp = NULL;
3992 matchres.vcount = 0;
3994 /* Pick right bitmask word from Bloom filter array */
3995 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
3996 obj->maskwords_bm_gnu];
3998 /* Calculate modulus word size of gnu hash and its derivative */
3999 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4000 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4002 /* Filter out the "definitely not in set" queries */
4003 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4006 /* Locate hash chain and corresponding value element*/
4007 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4010 hashval = &obj->chain_zero_gnu[bucket];
4012 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4013 symnum = hashval - obj->chain_zero_gnu;
4014 if (matched_symbol(req, obj, &matchres, symnum)) {
4015 req->sym_out = matchres.sym_out;
4016 req->defobj_out = obj;
4020 } while ((*hashval++ & 1) == 0);
4021 if (matchres.vcount == 1) {
4022 req->sym_out = matchres.vsymp;
4023 req->defobj_out = obj;
4030 trace_loaded_objects(Obj_Entry *obj)
4032 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4035 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
4038 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL)
4039 fmt1 = "\t%o => %p (%x)\n";
4041 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL)
4042 fmt2 = "\t%o (%x)\n";
4044 list_containers = _getenv_ld("LD_TRACE_LOADED_OBJECTS_ALL");
4046 for (; obj; obj = obj->next) {
4047 Needed_Entry *needed;
4051 if (list_containers && obj->needed != NULL)
4052 rtld_printf("%s:\n", obj->path);
4053 for (needed = obj->needed; needed; needed = needed->next) {
4054 if (needed->obj != NULL) {
4055 if (needed->obj->traced && !list_containers)
4057 needed->obj->traced = true;
4058 path = needed->obj->path;
4062 name = (char *)obj->strtab + needed->name;
4063 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4065 fmt = is_lib ? fmt1 : fmt2;
4066 while ((c = *fmt++) != '\0') {
4092 rtld_putstr(main_local);
4095 rtld_putstr(obj_main->path);
4104 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4117 * Unload a dlopened object and its dependencies from memory and from
4118 * our data structures. It is assumed that the DAG rooted in the
4119 * object has already been unreferenced, and that the object has a
4120 * reference count of 0.
4123 unload_object(Obj_Entry *root)
4128 assert(root->refcount == 0);
4131 * Pass over the DAG removing unreferenced objects from
4132 * appropriate lists.
4134 unlink_object(root);
4136 /* Unmap all objects that are no longer referenced. */
4137 linkp = &obj_list->next;
4138 while ((obj = *linkp) != NULL) {
4139 if (obj->refcount == 0) {
4140 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4142 dbg("unloading \"%s\"", obj->path);
4143 unload_filtees(root);
4144 munmap(obj->mapbase, obj->mapsize);
4145 linkmap_delete(obj);
4156 unlink_object(Obj_Entry *root)
4160 if (root->refcount == 0) {
4161 /* Remove the object from the RTLD_GLOBAL list. */
4162 objlist_remove(&list_global, root);
4164 /* Remove the object from all objects' DAG lists. */
4165 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4166 objlist_remove(&elm->obj->dldags, root);
4167 if (elm->obj != root)
4168 unlink_object(elm->obj);
4174 ref_dag(Obj_Entry *root)
4178 assert(root->dag_inited);
4179 STAILQ_FOREACH(elm, &root->dagmembers, link)
4180 elm->obj->refcount++;
4184 unref_dag(Obj_Entry *root)
4188 assert(root->dag_inited);
4189 STAILQ_FOREACH(elm, &root->dagmembers, link)
4190 elm->obj->refcount--;
4194 * Common code for MD __tls_get_addr().
4197 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset)
4199 Elf_Addr* dtv = *dtvp;
4200 RtldLockState lockstate;
4202 /* Check dtv generation in case new modules have arrived */
4203 if (dtv[0] != tls_dtv_generation) {
4207 wlock_acquire(rtld_bind_lock, &lockstate);
4208 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4210 if (to_copy > tls_max_index)
4211 to_copy = tls_max_index;
4212 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4213 newdtv[0] = tls_dtv_generation;
4214 newdtv[1] = tls_max_index;
4216 lock_release(rtld_bind_lock, &lockstate);
4217 dtv = *dtvp = newdtv;
4220 /* Dynamically allocate module TLS if necessary */
4221 if (!dtv[index + 1]) {
4222 /* Signal safe, wlock will block out signals. */
4223 wlock_acquire(rtld_bind_lock, &lockstate);
4224 if (!dtv[index + 1])
4225 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4226 lock_release(rtld_bind_lock, &lockstate);
4228 return (void*) (dtv[index + 1] + offset);
4231 #if defined(RTLD_STATIC_TLS_VARIANT_II)
4234 * Allocate the static TLS area. Return a pointer to the TCB. The
4235 * static area is based on negative offsets relative to the tcb.
4237 * The TCB contains an errno pointer for the system call layer, but because
4238 * we are the RTLD we really have no idea how the caller was compiled so
4239 * the information has to be passed in. errno can either be:
4241 * type 0 errno is a simple non-TLS global pointer.
4242 * (special case for e.g. libc_rtld)
4243 * type 1 errno accessed by GOT entry (dynamically linked programs)
4244 * type 2 errno accessed by %gs:OFFSET (statically linked programs)
4247 allocate_tls(Obj_Entry *objs)
4252 struct tls_tcb *tcb;
4257 * Allocate the new TCB. static TLS storage is placed just before the
4258 * TCB to support the %gs:OFFSET (negative offset) model.
4260 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
4261 ~RTLD_STATIC_TLS_ALIGN_MASK;
4262 tcb = malloc(data_size + sizeof(*tcb));
4263 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */
4265 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr);
4266 dtv = malloc(dtv_size);
4267 bzero(dtv, dtv_size);
4269 #ifdef RTLD_TCB_HAS_SELF_POINTER
4270 tcb->tcb_self = tcb;
4273 tcb->tcb_pthread = NULL;
4275 dtv[0] = tls_dtv_generation;
4276 dtv[1] = tls_max_index;
4278 for (obj = objs; obj; obj = obj->next) {
4279 if (obj->tlsoffset) {
4280 addr = (Elf_Addr)tcb - obj->tlsoffset;
4281 memset((void *)(addr + obj->tlsinitsize),
4282 0, obj->tlssize - obj->tlsinitsize);
4284 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4285 dtv[obj->tlsindex + 1] = addr;
4292 free_tls(struct tls_tcb *tcb)
4296 Elf_Addr tls_start, tls_end;
4299 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
4300 ~RTLD_STATIC_TLS_ALIGN_MASK;
4304 tls_end = (Elf_Addr)tcb;
4305 tls_start = (Elf_Addr)tcb - data_size;
4306 for (i = 0; i < dtv_size; i++) {
4307 if (dtv[i+2] != 0 && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) {
4308 free((void *)dtv[i+2]);
4312 free((void*) tls_start);
4316 #error "Unsupported TLS layout"
4320 * Allocate TLS block for module with given index.
4323 allocate_module_tls(int index)
4328 for (obj = obj_list; obj; obj = obj->next) {
4329 if (obj->tlsindex == index)
4333 _rtld_error("Can't find module with TLS index %d", index);
4337 p = malloc(obj->tlssize);
4339 _rtld_error("Cannot allocate TLS block for index %d", index);
4342 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4343 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4349 allocate_tls_offset(Obj_Entry *obj)
4356 if (obj->tlssize == 0) {
4357 obj->tls_done = true;
4361 if (obj->tlsindex == 1)
4362 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4364 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4365 obj->tlssize, obj->tlsalign);
4368 * If we have already fixed the size of the static TLS block, we
4369 * must stay within that size. When allocating the static TLS, we
4370 * leave a small amount of space spare to be used for dynamically
4371 * loading modules which use static TLS.
4373 if (tls_static_space) {
4374 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4378 tls_last_offset = obj->tlsoffset = off;
4379 tls_last_size = obj->tlssize;
4380 obj->tls_done = true;
4386 free_tls_offset(Obj_Entry *obj)
4388 #ifdef RTLD_STATIC_TLS_VARIANT_II
4390 * If we were the last thing to allocate out of the static TLS
4391 * block, we give our space back to the 'allocator'. This is a
4392 * simplistic workaround to allow libGL.so.1 to be loaded and
4393 * unloaded multiple times. We only handle the Variant II
4394 * mechanism for now - this really needs a proper allocator.
4396 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4397 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4398 tls_last_offset -= obj->tlssize;
4405 _rtld_allocate_tls(void)
4407 struct tls_tcb *new_tcb;
4408 RtldLockState lockstate;
4410 wlock_acquire(rtld_bind_lock, &lockstate);
4411 new_tcb = allocate_tls(obj_list);
4412 lock_release(rtld_bind_lock, &lockstate);
4417 _rtld_free_tls(struct tls_tcb *tcb)
4419 RtldLockState lockstate;
4421 wlock_acquire(rtld_bind_lock, &lockstate);
4423 lock_release(rtld_bind_lock, &lockstate);
4427 object_add_name(Obj_Entry *obj, const char *name)
4433 entry = malloc(sizeof(Name_Entry) + len);
4435 if (entry != NULL) {
4436 strcpy(entry->name, name);
4437 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4442 object_match_name(const Obj_Entry *obj, const char *name)
4446 STAILQ_FOREACH(entry, &obj->names, link) {
4447 if (strcmp(name, entry->name) == 0)
4454 locate_dependency(const Obj_Entry *obj, const char *name)
4456 const Objlist_Entry *entry;
4457 const Needed_Entry *needed;
4459 STAILQ_FOREACH(entry, &list_main, link) {
4460 if (object_match_name(entry->obj, name))
4464 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4465 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4466 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4468 * If there is DT_NEEDED for the name we are looking for,
4469 * we are all set. Note that object might not be found if
4470 * dependency was not loaded yet, so the function can
4471 * return NULL here. This is expected and handled
4472 * properly by the caller.
4474 return (needed->obj);
4477 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4483 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4484 const Elf_Vernaux *vna)
4486 const Elf_Verdef *vd;
4487 const char *vername;
4489 vername = refobj->strtab + vna->vna_name;
4490 vd = depobj->verdef;
4492 _rtld_error("%s: version %s required by %s not defined",
4493 depobj->path, vername, refobj->path);
4497 if (vd->vd_version != VER_DEF_CURRENT) {
4498 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4499 depobj->path, vd->vd_version);
4502 if (vna->vna_hash == vd->vd_hash) {
4503 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4504 ((char *)vd + vd->vd_aux);
4505 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4508 if (vd->vd_next == 0)
4510 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4512 if (vna->vna_flags & VER_FLG_WEAK)
4514 _rtld_error("%s: version %s required by %s not found",
4515 depobj->path, vername, refobj->path);
4520 rtld_verify_object_versions(Obj_Entry *obj)
4522 const Elf_Verneed *vn;
4523 const Elf_Verdef *vd;
4524 const Elf_Verdaux *vda;
4525 const Elf_Vernaux *vna;
4526 const Obj_Entry *depobj;
4527 int maxvernum, vernum;
4529 if (obj->ver_checked)
4531 obj->ver_checked = true;
4535 * Walk over defined and required version records and figure out
4536 * max index used by any of them. Do very basic sanity checking
4540 while (vn != NULL) {
4541 if (vn->vn_version != VER_NEED_CURRENT) {
4542 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4543 obj->path, vn->vn_version);
4546 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4548 vernum = VER_NEED_IDX(vna->vna_other);
4549 if (vernum > maxvernum)
4551 if (vna->vna_next == 0)
4553 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4555 if (vn->vn_next == 0)
4557 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4561 while (vd != NULL) {
4562 if (vd->vd_version != VER_DEF_CURRENT) {
4563 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4564 obj->path, vd->vd_version);
4567 vernum = VER_DEF_IDX(vd->vd_ndx);
4568 if (vernum > maxvernum)
4570 if (vd->vd_next == 0)
4572 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4579 * Store version information in array indexable by version index.
4580 * Verify that object version requirements are satisfied along the
4583 obj->vernum = maxvernum + 1;
4584 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4587 while (vd != NULL) {
4588 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4589 vernum = VER_DEF_IDX(vd->vd_ndx);
4590 assert(vernum <= maxvernum);
4591 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4592 obj->vertab[vernum].hash = vd->vd_hash;
4593 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4594 obj->vertab[vernum].file = NULL;
4595 obj->vertab[vernum].flags = 0;
4597 if (vd->vd_next == 0)
4599 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4603 while (vn != NULL) {
4604 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4607 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4609 if (check_object_provided_version(obj, depobj, vna))
4611 vernum = VER_NEED_IDX(vna->vna_other);
4612 assert(vernum <= maxvernum);
4613 obj->vertab[vernum].hash = vna->vna_hash;
4614 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4615 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4616 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4617 VER_INFO_HIDDEN : 0;
4618 if (vna->vna_next == 0)
4620 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4622 if (vn->vn_next == 0)
4624 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4630 rtld_verify_versions(const Objlist *objlist)
4632 Objlist_Entry *entry;
4636 STAILQ_FOREACH(entry, objlist, link) {
4638 * Skip dummy objects or objects that have their version requirements
4641 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4643 if (rtld_verify_object_versions(entry->obj) == -1) {
4645 if (ld_tracing == NULL)
4649 if (rc == 0 || ld_tracing != NULL)
4650 rc = rtld_verify_object_versions(&obj_rtld);
4655 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4660 vernum = VER_NDX(obj->versyms[symnum]);
4661 if (vernum >= obj->vernum) {
4662 _rtld_error("%s: symbol %s has wrong verneed value %d",
4663 obj->path, obj->strtab + symnum, vernum);
4664 } else if (obj->vertab[vernum].hash != 0) {
4665 return &obj->vertab[vernum];
4672 _rtld_get_stack_prot(void)
4675 return (stack_prot);
4679 map_stacks_exec(RtldLockState *lockstate)
4683 * Stack protection must be implemented in the kernel before the dynamic
4684 * linker can handle PT_GNU_STACK sections.
4685 * The following is the FreeBSD implementation of map_stacks_exec()
4686 * void (*thr_map_stacks_exec)(void);
4688 * if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4690 * thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4691 * get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4692 * if (thr_map_stacks_exec != NULL) {
4693 * stack_prot |= PROT_EXEC;
4694 * thr_map_stacks_exec();
4700 symlook_init(SymLook *dst, const char *name)
4703 bzero(dst, sizeof(*dst));
4705 dst->hash = elf_hash(name);
4706 dst->hash_gnu = gnu_hash(name);
4710 symlook_init_from_req(SymLook *dst, const SymLook *src)
4713 dst->name = src->name;
4714 dst->hash = src->hash;
4715 dst->hash_gnu = src->hash_gnu;
4716 dst->ventry = src->ventry;
4717 dst->flags = src->flags;
4718 dst->defobj_out = NULL;
4719 dst->sym_out = NULL;
4720 dst->lockstate = src->lockstate;
4723 #ifdef ENABLE_OSRELDATE
4725 * Overrides for libc_pic-provided functions.
4729 __getosreldate(void)
4739 oid[1] = KERN_OSRELDATE;
4741 len = sizeof(osrel);
4742 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4743 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4750 * No unresolved symbols for rtld.
4753 __pthread_cxa_finalize(struct dl_phdr_info *a)
4758 rtld_strerror(int errnum)
4761 if (errnum < 0 || errnum >= sys_nerr)
4762 return ("Unknown error");
4763 return (sys_errlist[errnum]);