2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * Copyright 2009, 2010, 2011 Konstantin Belousov <kib@FreeBSD.ORG>.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 * Dynamic linker for ELF.
33 * John Polstra <jdp@polstra.com>.
37 #error "GCC is needed to compile this file"
40 #include <sys/param.h>
41 #include <sys/mount.h>
44 #include <sys/sysctl.h>
46 #include <sys/utsname.h>
47 #include <sys/ktrace.h>
63 #include "rtld_printf.h"
66 #define PATH_RTLD "/libexec/ld-elf.so.1"
68 #define PATH_RTLD "/libexec/ld-elf32.so.1"
72 typedef void (*func_ptr_type)();
73 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
76 * Function declarations.
78 static const char *basename(const char *);
79 static void die(void) __dead2;
80 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
82 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *);
83 static void digest_dynamic(Obj_Entry *, int);
84 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
85 static Obj_Entry *dlcheck(void *);
86 static Obj_Entry *dlopen_object(const char *name, Obj_Entry *refobj,
87 int lo_flags, int mode);
88 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
89 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
90 static bool donelist_check(DoneList *, const Obj_Entry *);
91 static void errmsg_restore(char *);
92 static char *errmsg_save(void);
93 static void *fill_search_info(const char *, size_t, void *);
94 static char *find_library(const char *, const Obj_Entry *);
95 static const char *gethints(void);
96 static void init_dag(Obj_Entry *);
97 static void init_rtld(caddr_t, Elf_Auxinfo **);
98 static void initlist_add_neededs(Needed_Entry *, Objlist *);
99 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
100 static void linkmap_add(Obj_Entry *);
101 static void linkmap_delete(Obj_Entry *);
102 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
103 static void unload_filtees(Obj_Entry *);
104 static int load_needed_objects(Obj_Entry *, int);
105 static int load_preload_objects(void);
106 static Obj_Entry *load_object(const char *, const Obj_Entry *, int);
107 static void map_stacks_exec(RtldLockState *);
108 static Obj_Entry *obj_from_addr(const void *);
109 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
110 static void objlist_call_init(Objlist *, RtldLockState *);
111 static void objlist_clear(Objlist *);
112 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
113 static void objlist_init(Objlist *);
114 static void objlist_push_head(Objlist *, Obj_Entry *);
115 static void objlist_push_tail(Objlist *, Obj_Entry *);
116 static void objlist_remove(Objlist *, Obj_Entry *);
117 static void *path_enumerate(const char *, path_enum_proc, void *);
118 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, RtldLockState *);
119 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
120 RtldLockState *lockstate);
121 static int rtld_dirname(const char *, char *);
122 static int rtld_dirname_abs(const char *, char *);
123 static void rtld_exit(void);
124 static char *search_library_path(const char *, const char *);
125 static const void **get_program_var_addr(const char *, RtldLockState *);
126 static void set_program_var(const char *, const void *);
127 static int symlook_default(SymLook *, const Obj_Entry *refobj);
128 static int symlook_global(SymLook *, DoneList *);
129 static void symlook_init_from_req(SymLook *, const SymLook *);
130 static int symlook_list(SymLook *, const Objlist *, DoneList *);
131 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
132 static int symlook_obj1(SymLook *, const Obj_Entry *);
133 static void trace_loaded_objects(Obj_Entry *);
134 static void unlink_object(Obj_Entry *);
135 static void unload_object(Obj_Entry *);
136 static void unref_dag(Obj_Entry *);
137 static void ref_dag(Obj_Entry *);
138 static int origin_subst_one(char **, const char *, const char *,
139 const char *, char *);
140 static char *origin_subst(const char *, const char *);
141 static int rtld_verify_versions(const Objlist *);
142 static int rtld_verify_object_versions(Obj_Entry *);
143 static void object_add_name(Obj_Entry *, const char *);
144 static int object_match_name(const Obj_Entry *, const char *);
145 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
146 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
147 struct dl_phdr_info *phdr_info);
149 void r_debug_state(struct r_debug *, struct link_map *) __noinline;
154 static char *error_message; /* Message for dlerror(), or NULL */
155 struct r_debug r_debug; /* for GDB; */
156 static bool libmap_disable; /* Disable libmap */
157 static bool ld_loadfltr; /* Immediate filters processing */
158 static char *libmap_override; /* Maps to use in addition to libmap.conf */
159 static bool trust; /* False for setuid and setgid programs */
160 static bool dangerous_ld_env; /* True if environment variables have been
161 used to affect the libraries loaded */
162 static char *ld_bind_now; /* Environment variable for immediate binding */
163 static char *ld_debug; /* Environment variable for debugging */
164 static char *ld_library_path; /* Environment variable for search path */
165 static char *ld_preload; /* Environment variable for libraries to
167 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
168 static char *ld_tracing; /* Called from ldd to print libs */
169 static char *ld_utrace; /* Use utrace() to log events. */
170 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
171 static Obj_Entry **obj_tail; /* Link field of last object in list */
172 static Obj_Entry *obj_main; /* The main program shared object */
173 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
174 static unsigned int obj_count; /* Number of objects in obj_list */
175 static unsigned int obj_loads; /* Number of objects in obj_list */
177 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
178 STAILQ_HEAD_INITIALIZER(list_global);
179 static Objlist list_main = /* Objects loaded at program startup */
180 STAILQ_HEAD_INITIALIZER(list_main);
181 static Objlist list_fini = /* Objects needing fini() calls */
182 STAILQ_HEAD_INITIALIZER(list_fini);
184 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
186 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
188 extern Elf_Dyn _DYNAMIC;
189 #pragma weak _DYNAMIC
190 #ifndef RTLD_IS_DYNAMIC
191 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
194 int osreldate, pagesize;
196 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
197 static int max_stack_flags;
200 * Global declarations normally provided by crt1. The dynamic linker is
201 * not built with crt1, so we have to provide them ourselves.
207 * Globals to control TLS allocation.
209 size_t tls_last_offset; /* Static TLS offset of last module */
210 size_t tls_last_size; /* Static TLS size of last module */
211 size_t tls_static_space; /* Static TLS space allocated */
212 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
213 int tls_max_index = 1; /* Largest module index allocated */
216 * Fill in a DoneList with an allocation large enough to hold all of
217 * the currently-loaded objects. Keep this as a macro since it calls
218 * alloca and we want that to occur within the scope of the caller.
220 #define donelist_init(dlp) \
221 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
222 assert((dlp)->objs != NULL), \
223 (dlp)->num_alloc = obj_count, \
226 #define UTRACE_DLOPEN_START 1
227 #define UTRACE_DLOPEN_STOP 2
228 #define UTRACE_DLCLOSE_START 3
229 #define UTRACE_DLCLOSE_STOP 4
230 #define UTRACE_LOAD_OBJECT 5
231 #define UTRACE_UNLOAD_OBJECT 6
232 #define UTRACE_ADD_RUNDEP 7
233 #define UTRACE_PRELOAD_FINISHED 8
234 #define UTRACE_INIT_CALL 9
235 #define UTRACE_FINI_CALL 10
238 char sig[4]; /* 'RTLD' */
241 void *mapbase; /* Used for 'parent' and 'init/fini' */
243 int refcnt; /* Used for 'mode' */
244 char name[MAXPATHLEN];
247 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
248 if (ld_utrace != NULL) \
249 ld_utrace_log(e, h, mb, ms, r, n); \
253 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
254 int refcnt, const char *name)
256 struct utrace_rtld ut;
264 ut.mapbase = mapbase;
265 ut.mapsize = mapsize;
267 bzero(ut.name, sizeof(ut.name));
269 strlcpy(ut.name, name, sizeof(ut.name));
270 utrace(&ut, sizeof(ut));
274 * Main entry point for dynamic linking. The first argument is the
275 * stack pointer. The stack is expected to be laid out as described
276 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
277 * Specifically, the stack pointer points to a word containing
278 * ARGC. Following that in the stack is a null-terminated sequence
279 * of pointers to argument strings. Then comes a null-terminated
280 * sequence of pointers to environment strings. Finally, there is a
281 * sequence of "auxiliary vector" entries.
283 * The second argument points to a place to store the dynamic linker's
284 * exit procedure pointer and the third to a place to store the main
287 * The return value is the main program's entry point.
290 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
292 Elf_Auxinfo *aux_info[AT_COUNT];
300 Objlist_Entry *entry;
302 Obj_Entry **preload_tail;
304 RtldLockState lockstate;
307 * On entry, the dynamic linker itself has not been relocated yet.
308 * Be very careful not to reference any global data until after
309 * init_rtld has returned. It is OK to reference file-scope statics
310 * and string constants, and to call static and global functions.
313 /* Find the auxiliary vector on the stack. */
316 sp += argc + 1; /* Skip over arguments and NULL terminator */
318 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
320 aux = (Elf_Auxinfo *) sp;
322 /* Digest the auxiliary vector. */
323 for (i = 0; i < AT_COUNT; i++)
325 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
326 if (auxp->a_type < AT_COUNT)
327 aux_info[auxp->a_type] = auxp;
330 /* Initialize and relocate ourselves. */
331 assert(aux_info[AT_BASE] != NULL);
332 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
334 __progname = obj_rtld.path;
335 argv0 = argv[0] != NULL ? argv[0] : "(null)";
338 trust = !issetugid();
340 ld_bind_now = getenv(LD_ "BIND_NOW");
342 * If the process is tainted, then we un-set the dangerous environment
343 * variables. The process will be marked as tainted until setuid(2)
344 * is called. If any child process calls setuid(2) we do not want any
345 * future processes to honor the potentially un-safe variables.
348 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
349 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") ||
350 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
351 unsetenv(LD_ "LOADFLTR")) {
352 _rtld_error("environment corrupt; aborting");
356 ld_debug = getenv(LD_ "DEBUG");
357 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
358 libmap_override = getenv(LD_ "LIBMAP");
359 ld_library_path = getenv(LD_ "LIBRARY_PATH");
360 ld_preload = getenv(LD_ "PRELOAD");
361 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
362 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
363 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
364 (ld_library_path != NULL) || (ld_preload != NULL) ||
365 (ld_elf_hints_path != NULL) || ld_loadfltr;
366 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
367 ld_utrace = getenv(LD_ "UTRACE");
369 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
370 ld_elf_hints_path = _PATH_ELF_HINTS;
372 if (ld_debug != NULL && *ld_debug != '\0')
374 dbg("%s is initialized, base address = %p", __progname,
375 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
376 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
377 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
379 dbg("initializing thread locks");
383 * Load the main program, or process its program header if it is
386 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
387 int fd = aux_info[AT_EXECFD]->a_un.a_val;
388 dbg("loading main program");
389 obj_main = map_object(fd, argv0, NULL);
391 if (obj_main == NULL)
393 max_stack_flags = obj->stack_flags;
394 } else { /* Main program already loaded. */
395 const Elf_Phdr *phdr;
399 dbg("processing main program's program header");
400 assert(aux_info[AT_PHDR] != NULL);
401 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
402 assert(aux_info[AT_PHNUM] != NULL);
403 phnum = aux_info[AT_PHNUM]->a_un.a_val;
404 assert(aux_info[AT_PHENT] != NULL);
405 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
406 assert(aux_info[AT_ENTRY] != NULL);
407 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
408 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
412 if (aux_info[AT_EXECPATH] != 0) {
414 char buf[MAXPATHLEN];
416 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
417 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
418 if (kexecpath[0] == '/')
419 obj_main->path = kexecpath;
420 else if (getcwd(buf, sizeof(buf)) == NULL ||
421 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
422 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
423 obj_main->path = xstrdup(argv0);
425 obj_main->path = xstrdup(buf);
427 dbg("No AT_EXECPATH");
428 obj_main->path = xstrdup(argv0);
430 dbg("obj_main path %s", obj_main->path);
431 obj_main->mainprog = true;
433 if (aux_info[AT_STACKPROT] != NULL &&
434 aux_info[AT_STACKPROT]->a_un.a_val != 0)
435 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
438 * Get the actual dynamic linker pathname from the executable if
439 * possible. (It should always be possible.) That ensures that
440 * gdb will find the right dynamic linker even if a non-standard
443 if (obj_main->interp != NULL &&
444 strcmp(obj_main->interp, obj_rtld.path) != 0) {
446 obj_rtld.path = xstrdup(obj_main->interp);
447 __progname = obj_rtld.path;
450 digest_dynamic(obj_main, 0);
452 linkmap_add(obj_main);
453 linkmap_add(&obj_rtld);
455 /* Link the main program into the list of objects. */
456 *obj_tail = obj_main;
457 obj_tail = &obj_main->next;
460 /* Make sure we don't call the main program's init and fini functions. */
461 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
463 /* Initialize a fake symbol for resolving undefined weak references. */
464 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
465 sym_zero.st_shndx = SHN_UNDEF;
466 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
469 libmap_disable = (bool)lm_init(libmap_override);
471 dbg("loading LD_PRELOAD libraries");
472 if (load_preload_objects() == -1)
474 preload_tail = obj_tail;
476 dbg("loading needed objects");
477 if (load_needed_objects(obj_main, 0) == -1)
480 /* Make a list of all objects loaded at startup. */
481 for (obj = obj_list; obj != NULL; obj = obj->next) {
482 objlist_push_tail(&list_main, obj);
486 dbg("checking for required versions");
487 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
490 if (ld_tracing) { /* We're done */
491 trace_loaded_objects(obj_main);
495 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
496 dump_relocations(obj_main);
501 * Processing tls relocations requires having the tls offsets
502 * initialized. Prepare offsets before starting initial
503 * relocation processing.
505 dbg("initializing initial thread local storage offsets");
506 STAILQ_FOREACH(entry, &list_main, link) {
508 * Allocate all the initial objects out of the static TLS
509 * block even if they didn't ask for it.
511 allocate_tls_offset(entry->obj);
514 if (relocate_objects(obj_main,
515 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld, NULL) == -1)
518 dbg("doing copy relocations");
519 if (do_copy_relocations(obj_main) == -1)
522 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
523 dump_relocations(obj_main);
528 * Setup TLS for main thread. This must be done after the
529 * relocations are processed, since tls initialization section
530 * might be the subject for relocations.
532 dbg("initializing initial thread local storage");
533 allocate_initial_tls(obj_list);
535 dbg("initializing key program variables");
536 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
537 set_program_var("environ", env);
538 set_program_var("__elf_aux_vector", aux);
540 /* Make a list of init functions to call. */
541 objlist_init(&initlist);
542 initlist_add_objects(obj_list, preload_tail, &initlist);
544 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
546 map_stacks_exec(NULL);
548 dbg("resolving ifuncs");
549 if (resolve_objects_ifunc(obj_main,
550 ld_bind_now != NULL && *ld_bind_now != '\0', NULL) == -1)
553 wlock_acquire(rtld_bind_lock, &lockstate);
554 objlist_call_init(&initlist, &lockstate);
555 objlist_clear(&initlist);
556 dbg("loading filtees");
557 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
558 if (ld_loadfltr || obj->z_loadfltr)
559 load_filtees(obj, 0, &lockstate);
561 lock_release(rtld_bind_lock, &lockstate);
563 dbg("transferring control to program entry point = %p", obj_main->entry);
565 /* Return the exit procedure and the program entry point. */
566 *exit_proc = rtld_exit;
568 return (func_ptr_type) obj_main->entry;
572 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
577 ptr = (void *)make_function_pointer(def, obj);
578 target = ((Elf_Addr (*)(void))ptr)();
579 return ((void *)target);
583 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
587 const Obj_Entry *defobj;
590 RtldLockState lockstate;
592 rlock_acquire(rtld_bind_lock, &lockstate);
593 if (sigsetjmp(lockstate.env, 0) != 0)
594 lock_upgrade(rtld_bind_lock, &lockstate);
596 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
598 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
600 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
601 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
605 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
606 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
608 target = (Elf_Addr)(defobj->relocbase + def->st_value);
610 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
611 defobj->strtab + def->st_name, basename(obj->path),
612 (void *)target, basename(defobj->path));
615 * Write the new contents for the jmpslot. Note that depending on
616 * architecture, the value which we need to return back to the
617 * lazy binding trampoline may or may not be the target
618 * address. The value returned from reloc_jmpslot() is the value
619 * that the trampoline needs.
621 target = reloc_jmpslot(where, target, defobj, obj, rel);
622 lock_release(rtld_bind_lock, &lockstate);
627 * Error reporting function. Use it like printf. If formats the message
628 * into a buffer, and sets things up so that the next call to dlerror()
629 * will return the message.
632 _rtld_error(const char *fmt, ...)
634 static char buf[512];
638 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
644 * Return a dynamically-allocated copy of the current error message, if any.
649 return error_message == NULL ? NULL : xstrdup(error_message);
653 * Restore the current error message from a copy which was previously saved
654 * by errmsg_save(). The copy is freed.
657 errmsg_restore(char *saved_msg)
659 if (saved_msg == NULL)
660 error_message = NULL;
662 _rtld_error("%s", saved_msg);
668 basename(const char *name)
670 const char *p = strrchr(name, '/');
671 return p != NULL ? p + 1 : name;
674 static struct utsname uts;
677 origin_subst_one(char **res, const char *real, const char *kw, const char *subst,
687 subst_len = kw_len = 0;
691 if (subst_len == 0) {
692 subst_len = strlen(subst);
696 *res = xmalloc(PATH_MAX);
699 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) {
700 _rtld_error("Substitution of %s in %s cannot be performed",
702 if (may_free != NULL)
707 memcpy(res1, p, p1 - p);
709 memcpy(res1, subst, subst_len);
714 if (may_free != NULL)
717 *res = xstrdup(real);
721 if (may_free != NULL)
723 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) {
733 origin_subst(const char *real, const char *origin_path)
735 char *res1, *res2, *res3, *res4;
737 if (uts.sysname[0] == '\0') {
738 if (uname(&uts) != 0) {
739 _rtld_error("utsname failed: %d", errno);
743 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) ||
744 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) ||
745 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) ||
746 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3))
754 const char *msg = dlerror();
758 rtld_fdputstr(STDERR_FILENO, msg);
763 * Process a shared object's DYNAMIC section, and save the important
764 * information in its Obj_Entry structure.
767 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
768 const Elf_Dyn **dyn_soname)
771 Needed_Entry **needed_tail = &obj->needed;
772 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
773 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
774 int plttype = DT_REL;
779 obj->bind_now = false;
780 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
781 switch (dynp->d_tag) {
784 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
788 obj->relsize = dynp->d_un.d_val;
792 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
796 obj->pltrel = (const Elf_Rel *)
797 (obj->relocbase + dynp->d_un.d_ptr);
801 obj->pltrelsize = dynp->d_un.d_val;
805 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
809 obj->relasize = dynp->d_un.d_val;
813 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
817 plttype = dynp->d_un.d_val;
818 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
822 obj->symtab = (const Elf_Sym *)
823 (obj->relocbase + dynp->d_un.d_ptr);
827 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
831 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
835 obj->strsize = dynp->d_un.d_val;
839 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
844 obj->verneednum = dynp->d_un.d_val;
848 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
853 obj->verdefnum = dynp->d_un.d_val;
857 obj->versyms = (const Elf_Versym *)(obj->relocbase +
863 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
864 (obj->relocbase + dynp->d_un.d_ptr);
865 obj->nbuckets = hashtab[0];
866 obj->nchains = hashtab[1];
867 obj->buckets = hashtab + 2;
868 obj->chains = obj->buckets + obj->nbuckets;
874 Needed_Entry *nep = NEW(Needed_Entry);
875 nep->name = dynp->d_un.d_val;
880 needed_tail = &nep->next;
886 Needed_Entry *nep = NEW(Needed_Entry);
887 nep->name = dynp->d_un.d_val;
891 *needed_filtees_tail = nep;
892 needed_filtees_tail = &nep->next;
898 Needed_Entry *nep = NEW(Needed_Entry);
899 nep->name = dynp->d_un.d_val;
903 *needed_aux_filtees_tail = nep;
904 needed_aux_filtees_tail = &nep->next;
909 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
917 obj->symbolic = true;
921 case DT_RUNPATH: /* XXX: process separately */
923 * We have to wait until later to process this, because we
924 * might not have gotten the address of the string table yet.
934 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
938 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
942 * Don't process DT_DEBUG on MIPS as the dynamic section
943 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
948 /* XXX - not implemented yet */
950 dbg("Filling in DT_DEBUG entry");
951 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
956 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
957 obj->z_origin = true;
958 if (dynp->d_un.d_val & DF_SYMBOLIC)
959 obj->symbolic = true;
960 if (dynp->d_un.d_val & DF_TEXTREL)
962 if (dynp->d_un.d_val & DF_BIND_NOW)
963 obj->bind_now = true;
964 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
968 case DT_MIPS_LOCAL_GOTNO:
969 obj->local_gotno = dynp->d_un.d_val;
972 case DT_MIPS_SYMTABNO:
973 obj->symtabno = dynp->d_un.d_val;
977 obj->gotsym = dynp->d_un.d_val;
980 case DT_MIPS_RLD_MAP:
983 dbg("Filling in DT_DEBUG entry");
984 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
990 if (dynp->d_un.d_val & DF_1_NOOPEN)
991 obj->z_noopen = true;
992 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
993 obj->z_origin = true;
994 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
996 if (dynp->d_un.d_val & DF_1_BIND_NOW)
997 obj->bind_now = true;
998 if (dynp->d_un.d_val & DF_1_NODELETE)
999 obj->z_nodelete = true;
1000 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1001 obj->z_loadfltr = true;
1006 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1013 obj->traced = false;
1015 if (plttype == DT_RELA) {
1016 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1018 obj->pltrelasize = obj->pltrelsize;
1019 obj->pltrelsize = 0;
1024 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1025 const Elf_Dyn *dyn_soname)
1028 if (obj->z_origin && obj->origin_path == NULL) {
1029 obj->origin_path = xmalloc(PATH_MAX);
1030 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1034 if (dyn_rpath != NULL) {
1035 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1037 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1040 if (dyn_soname != NULL)
1041 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1045 digest_dynamic(Obj_Entry *obj, int early)
1047 const Elf_Dyn *dyn_rpath;
1048 const Elf_Dyn *dyn_soname;
1050 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname);
1051 digest_dynamic2(obj, dyn_rpath, dyn_soname);
1055 * Process a shared object's program header. This is used only for the
1056 * main program, when the kernel has already loaded the main program
1057 * into memory before calling the dynamic linker. It creates and
1058 * returns an Obj_Entry structure.
1061 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1064 const Elf_Phdr *phlimit = phdr + phnum;
1069 for (ph = phdr; ph < phlimit; ph++) {
1070 if (ph->p_type != PT_PHDR)
1074 obj->phsize = ph->p_memsz;
1075 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1079 obj->stack_flags = PF_X | PF_R | PF_W;
1081 for (ph = phdr; ph < phlimit; ph++) {
1082 switch (ph->p_type) {
1085 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1089 if (nsegs == 0) { /* First load segment */
1090 obj->vaddrbase = trunc_page(ph->p_vaddr);
1091 obj->mapbase = obj->vaddrbase + obj->relocbase;
1092 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1094 } else { /* Last load segment */
1095 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1102 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1107 obj->tlssize = ph->p_memsz;
1108 obj->tlsalign = ph->p_align;
1109 obj->tlsinitsize = ph->p_filesz;
1110 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1114 obj->stack_flags = ph->p_flags;
1119 _rtld_error("%s: too few PT_LOAD segments", path);
1128 dlcheck(void *handle)
1132 for (obj = obj_list; obj != NULL; obj = obj->next)
1133 if (obj == (Obj_Entry *) handle)
1136 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1137 _rtld_error("Invalid shared object handle %p", handle);
1144 * If the given object is already in the donelist, return true. Otherwise
1145 * add the object to the list and return false.
1148 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1152 for (i = 0; i < dlp->num_used; i++)
1153 if (dlp->objs[i] == obj)
1156 * Our donelist allocation should always be sufficient. But if
1157 * our threads locking isn't working properly, more shared objects
1158 * could have been loaded since we allocated the list. That should
1159 * never happen, but we'll handle it properly just in case it does.
1161 if (dlp->num_used < dlp->num_alloc)
1162 dlp->objs[dlp->num_used++] = obj;
1167 * Hash function for symbol table lookup. Don't even think about changing
1168 * this. It is specified by the System V ABI.
1171 elf_hash(const char *name)
1173 const unsigned char *p = (const unsigned char *) name;
1174 unsigned long h = 0;
1177 while (*p != '\0') {
1178 h = (h << 4) + *p++;
1179 if ((g = h & 0xf0000000) != 0)
1187 * Find the library with the given name, and return its full pathname.
1188 * The returned string is dynamically allocated. Generates an error
1189 * message and returns NULL if the library cannot be found.
1191 * If the second argument is non-NULL, then it refers to an already-
1192 * loaded shared object, whose library search path will be searched.
1194 * The search order is:
1196 * rpath in the referencing file
1201 find_library(const char *xname, const Obj_Entry *refobj)
1206 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1207 if (xname[0] != '/' && !trust) {
1208 _rtld_error("Absolute pathname required for shared object \"%s\"",
1212 if (refobj != NULL && refobj->z_origin)
1213 return origin_subst(xname, refobj->origin_path);
1215 return xstrdup(xname);
1218 if (libmap_disable || (refobj == NULL) ||
1219 (name = lm_find(refobj->path, xname)) == NULL)
1220 name = (char *)xname;
1222 dbg(" Searching for \"%s\"", name);
1224 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1226 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1227 (pathname = search_library_path(name, gethints())) != NULL ||
1228 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1231 if(refobj != NULL && refobj->path != NULL) {
1232 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1233 name, basename(refobj->path));
1235 _rtld_error("Shared object \"%s\" not found", name);
1241 * Given a symbol number in a referencing object, find the corresponding
1242 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1243 * no definition was found. Returns a pointer to the Obj_Entry of the
1244 * defining object via the reference parameter DEFOBJ_OUT.
1247 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1248 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1249 RtldLockState *lockstate)
1253 const Obj_Entry *defobj;
1259 * If we have already found this symbol, get the information from
1262 if (symnum >= refobj->nchains)
1263 return NULL; /* Bad object */
1264 if (cache != NULL && cache[symnum].sym != NULL) {
1265 *defobj_out = cache[symnum].obj;
1266 return cache[symnum].sym;
1269 ref = refobj->symtab + symnum;
1270 name = refobj->strtab + ref->st_name;
1275 * We don't have to do a full scale lookup if the symbol is local.
1276 * We know it will bind to the instance in this load module; to
1277 * which we already have a pointer (ie ref). By not doing a lookup,
1278 * we not only improve performance, but it also avoids unresolvable
1279 * symbols when local symbols are not in the hash table. This has
1280 * been seen with the ia64 toolchain.
1282 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1283 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1284 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1287 symlook_init(&req, name);
1289 req.ventry = fetch_ventry(refobj, symnum);
1290 req.lockstate = lockstate;
1291 res = symlook_default(&req, refobj);
1294 defobj = req.defobj_out;
1302 * If we found no definition and the reference is weak, treat the
1303 * symbol as having the value zero.
1305 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1311 *defobj_out = defobj;
1312 /* Record the information in the cache to avoid subsequent lookups. */
1313 if (cache != NULL) {
1314 cache[symnum].sym = def;
1315 cache[symnum].obj = defobj;
1318 if (refobj != &obj_rtld)
1319 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1325 * Return the search path from the ldconfig hints file, reading it if
1326 * necessary. Returns NULL if there are problems with the hints file,
1327 * or if the search path there is empty.
1334 if (hints == NULL) {
1336 struct elfhints_hdr hdr;
1339 /* Keep from trying again in case the hints file is bad. */
1342 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1)
1344 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1345 hdr.magic != ELFHINTS_MAGIC ||
1350 p = xmalloc(hdr.dirlistlen + 1);
1351 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1352 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) {
1360 return hints[0] != '\0' ? hints : NULL;
1364 init_dag(Obj_Entry *root)
1366 const Needed_Entry *needed;
1367 const Objlist_Entry *elm;
1370 if (root->dag_inited)
1372 donelist_init(&donelist);
1374 /* Root object belongs to own DAG. */
1375 objlist_push_tail(&root->dldags, root);
1376 objlist_push_tail(&root->dagmembers, root);
1377 donelist_check(&donelist, root);
1380 * Add dependencies of root object to DAG in breadth order
1381 * by exploiting the fact that each new object get added
1382 * to the tail of the dagmembers list.
1384 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1385 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1386 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1388 objlist_push_tail(&needed->obj->dldags, root);
1389 objlist_push_tail(&root->dagmembers, needed->obj);
1392 root->dag_inited = true;
1396 * Initialize the dynamic linker. The argument is the address at which
1397 * the dynamic linker has been mapped into memory. The primary task of
1398 * this function is to relocate the dynamic linker.
1401 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1403 Obj_Entry objtmp; /* Temporary rtld object */
1404 const Elf_Dyn *dyn_rpath;
1405 const Elf_Dyn *dyn_soname;
1408 * Conjure up an Obj_Entry structure for the dynamic linker.
1410 * The "path" member can't be initialized yet because string constants
1411 * cannot yet be accessed. Below we will set it correctly.
1413 memset(&objtmp, 0, sizeof(objtmp));
1416 objtmp.mapbase = mapbase;
1418 objtmp.relocbase = mapbase;
1420 if (RTLD_IS_DYNAMIC()) {
1421 objtmp.dynamic = rtld_dynamic(&objtmp);
1422 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname);
1423 assert(objtmp.needed == NULL);
1424 #if !defined(__mips__)
1425 /* MIPS has a bogus DT_TEXTREL. */
1426 assert(!objtmp.textrel);
1430 * Temporarily put the dynamic linker entry into the object list, so
1431 * that symbols can be found.
1434 relocate_objects(&objtmp, true, &objtmp, NULL);
1437 /* Initialize the object list. */
1438 obj_tail = &obj_list;
1440 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1441 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1443 if (aux_info[AT_PAGESZ] != NULL)
1444 pagesize = aux_info[AT_PAGESZ]->a_un.a_val;
1445 if (aux_info[AT_OSRELDATE] != NULL)
1446 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1448 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname);
1450 /* Replace the path with a dynamically allocated copy. */
1451 obj_rtld.path = xstrdup(PATH_RTLD);
1453 r_debug.r_brk = r_debug_state;
1454 r_debug.r_state = RT_CONSISTENT;
1458 * Add the init functions from a needed object list (and its recursive
1459 * needed objects) to "list". This is not used directly; it is a helper
1460 * function for initlist_add_objects(). The write lock must be held
1461 * when this function is called.
1464 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1466 /* Recursively process the successor needed objects. */
1467 if (needed->next != NULL)
1468 initlist_add_neededs(needed->next, list);
1470 /* Process the current needed object. */
1471 if (needed->obj != NULL)
1472 initlist_add_objects(needed->obj, &needed->obj->next, list);
1476 * Scan all of the DAGs rooted in the range of objects from "obj" to
1477 * "tail" and add their init functions to "list". This recurses over
1478 * the DAGs and ensure the proper init ordering such that each object's
1479 * needed libraries are initialized before the object itself. At the
1480 * same time, this function adds the objects to the global finalization
1481 * list "list_fini" in the opposite order. The write lock must be
1482 * held when this function is called.
1485 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1487 if (obj->init_scanned || obj->init_done)
1489 obj->init_scanned = true;
1491 /* Recursively process the successor objects. */
1492 if (&obj->next != tail)
1493 initlist_add_objects(obj->next, tail, list);
1495 /* Recursively process the needed objects. */
1496 if (obj->needed != NULL)
1497 initlist_add_neededs(obj->needed, list);
1499 /* Add the object to the init list. */
1500 if (obj->init != (Elf_Addr)NULL)
1501 objlist_push_tail(list, obj);
1503 /* Add the object to the global fini list in the reverse order. */
1504 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) {
1505 objlist_push_head(&list_fini, obj);
1506 obj->on_fini_list = true;
1511 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1515 free_needed_filtees(Needed_Entry *n)
1517 Needed_Entry *needed, *needed1;
1519 for (needed = n; needed != NULL; needed = needed->next) {
1520 if (needed->obj != NULL) {
1521 dlclose(needed->obj);
1525 for (needed = n; needed != NULL; needed = needed1) {
1526 needed1 = needed->next;
1532 unload_filtees(Obj_Entry *obj)
1535 free_needed_filtees(obj->needed_filtees);
1536 obj->needed_filtees = NULL;
1537 free_needed_filtees(obj->needed_aux_filtees);
1538 obj->needed_aux_filtees = NULL;
1539 obj->filtees_loaded = false;
1543 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags)
1546 for (; needed != NULL; needed = needed->next) {
1547 needed->obj = dlopen_object(obj->strtab + needed->name, obj,
1548 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
1554 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
1557 lock_restart_for_upgrade(lockstate);
1558 if (!obj->filtees_loaded) {
1559 load_filtee1(obj, obj->needed_filtees, flags);
1560 load_filtee1(obj, obj->needed_aux_filtees, flags);
1561 obj->filtees_loaded = true;
1566 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
1570 for (; needed != NULL; needed = needed->next) {
1571 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj,
1572 flags & ~RTLD_LO_NOLOAD);
1573 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
1575 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) {
1576 dbg("obj %s nodelete", obj1->path);
1579 obj1->ref_nodel = true;
1586 * Given a shared object, traverse its list of needed objects, and load
1587 * each of them. Returns 0 on success. Generates an error message and
1588 * returns -1 on failure.
1591 load_needed_objects(Obj_Entry *first, int flags)
1595 for (obj = first; obj != NULL; obj = obj->next) {
1596 if (process_needed(obj, obj->needed, flags) == -1)
1603 load_preload_objects(void)
1605 char *p = ld_preload;
1606 static const char delim[] = " \t:;";
1611 p += strspn(p, delim);
1612 while (*p != '\0') {
1613 size_t len = strcspn(p, delim);
1618 if (load_object(p, NULL, 0) == NULL)
1619 return -1; /* XXX - cleanup */
1622 p += strspn(p, delim);
1624 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
1629 * Load a shared object into memory, if it is not already loaded.
1631 * Returns a pointer to the Obj_Entry for the object. Returns NULL
1635 load_object(const char *name, const Obj_Entry *refobj, int flags)
1642 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1643 if (object_match_name(obj, name))
1646 path = find_library(name, refobj);
1651 * If we didn't find a match by pathname, open the file and check
1652 * again by device and inode. This avoids false mismatches caused
1653 * by multiple links or ".." in pathnames.
1655 * To avoid a race, we open the file and use fstat() rather than
1658 if ((fd = open(path, O_RDONLY)) == -1) {
1659 _rtld_error("Cannot open \"%s\"", path);
1663 if (fstat(fd, &sb) == -1) {
1664 _rtld_error("Cannot fstat \"%s\"", path);
1669 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1670 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
1673 object_add_name(obj, name);
1678 if (flags & RTLD_LO_NOLOAD) {
1684 /* First use of this object, so we must map it in */
1685 obj = do_load_object(fd, name, path, &sb, flags);
1694 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
1701 * but first, make sure that environment variables haven't been
1702 * used to circumvent the noexec flag on a filesystem.
1704 if (dangerous_ld_env) {
1705 if (fstatfs(fd, &fs) != 0) {
1706 _rtld_error("Cannot fstatfs \"%s\"", path);
1709 if (fs.f_flags & MNT_NOEXEC) {
1710 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
1714 dbg("loading \"%s\"", path);
1715 obj = map_object(fd, path, sbp);
1719 object_add_name(obj, name);
1721 digest_dynamic(obj, 0);
1722 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
1724 dbg("refusing to load non-loadable \"%s\"", obj->path);
1725 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
1726 munmap(obj->mapbase, obj->mapsize);
1732 obj_tail = &obj->next;
1735 linkmap_add(obj); /* for GDB & dlinfo() */
1736 max_stack_flags |= obj->stack_flags;
1738 dbg(" %p .. %p: %s", obj->mapbase,
1739 obj->mapbase + obj->mapsize - 1, obj->path);
1741 dbg(" WARNING: %s has impure text", obj->path);
1742 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
1749 obj_from_addr(const void *addr)
1753 for (obj = obj_list; obj != NULL; obj = obj->next) {
1754 if (addr < (void *) obj->mapbase)
1756 if (addr < (void *) (obj->mapbase + obj->mapsize))
1763 * Call the finalization functions for each of the objects in "list"
1764 * belonging to the DAG of "root" and referenced once. If NULL "root"
1765 * is specified, every finalization function will be called regardless
1766 * of the reference count and the list elements won't be freed. All of
1767 * the objects are expected to have non-NULL fini functions.
1770 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
1775 assert(root == NULL || root->refcount == 1);
1778 * Preserve the current error message since a fini function might
1779 * call into the dynamic linker and overwrite it.
1781 saved_msg = errmsg_save();
1783 STAILQ_FOREACH(elm, list, link) {
1784 if (root != NULL && (elm->obj->refcount != 1 ||
1785 objlist_find(&root->dagmembers, elm->obj) == NULL))
1787 dbg("calling fini function for %s at %p", elm->obj->path,
1788 (void *)elm->obj->fini);
1789 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0,
1791 /* Remove object from fini list to prevent recursive invocation. */
1792 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
1794 * XXX: If a dlopen() call references an object while the
1795 * fini function is in progress, we might end up trying to
1796 * unload the referenced object in dlclose() or the object
1797 * won't be unloaded although its fini function has been
1800 lock_release(rtld_bind_lock, lockstate);
1801 call_initfini_pointer(elm->obj, elm->obj->fini);
1802 wlock_acquire(rtld_bind_lock, lockstate);
1803 /* No need to free anything if process is going down. */
1807 * We must restart the list traversal after every fini call
1808 * because a dlclose() call from the fini function or from
1809 * another thread might have modified the reference counts.
1813 } while (elm != NULL);
1814 errmsg_restore(saved_msg);
1818 * Call the initialization functions for each of the objects in
1819 * "list". All of the objects are expected to have non-NULL init
1823 objlist_call_init(Objlist *list, RtldLockState *lockstate)
1830 * Clean init_scanned flag so that objects can be rechecked and
1831 * possibly initialized earlier if any of vectors called below
1832 * cause the change by using dlopen.
1834 for (obj = obj_list; obj != NULL; obj = obj->next)
1835 obj->init_scanned = false;
1838 * Preserve the current error message since an init function might
1839 * call into the dynamic linker and overwrite it.
1841 saved_msg = errmsg_save();
1842 STAILQ_FOREACH(elm, list, link) {
1843 if (elm->obj->init_done) /* Initialized early. */
1845 dbg("calling init function for %s at %p", elm->obj->path,
1846 (void *)elm->obj->init);
1847 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0,
1850 * Race: other thread might try to use this object before current
1851 * one completes the initilization. Not much can be done here
1852 * without better locking.
1854 elm->obj->init_done = true;
1855 lock_release(rtld_bind_lock, lockstate);
1856 call_initfini_pointer(elm->obj, elm->obj->init);
1857 wlock_acquire(rtld_bind_lock, lockstate);
1859 errmsg_restore(saved_msg);
1863 objlist_clear(Objlist *list)
1867 while (!STAILQ_EMPTY(list)) {
1868 elm = STAILQ_FIRST(list);
1869 STAILQ_REMOVE_HEAD(list, link);
1874 static Objlist_Entry *
1875 objlist_find(Objlist *list, const Obj_Entry *obj)
1879 STAILQ_FOREACH(elm, list, link)
1880 if (elm->obj == obj)
1886 objlist_init(Objlist *list)
1892 objlist_push_head(Objlist *list, Obj_Entry *obj)
1896 elm = NEW(Objlist_Entry);
1898 STAILQ_INSERT_HEAD(list, elm, link);
1902 objlist_push_tail(Objlist *list, Obj_Entry *obj)
1906 elm = NEW(Objlist_Entry);
1908 STAILQ_INSERT_TAIL(list, elm, link);
1912 objlist_remove(Objlist *list, Obj_Entry *obj)
1916 if ((elm = objlist_find(list, obj)) != NULL) {
1917 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
1923 * Relocate newly-loaded shared objects. The argument is a pointer to
1924 * the Obj_Entry for the first such object. All objects from the first
1925 * to the end of the list of objects are relocated. Returns 0 on success,
1929 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
1930 RtldLockState *lockstate)
1934 for (obj = first; obj != NULL; obj = obj->next) {
1936 dbg("relocating \"%s\"", obj->path);
1937 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL ||
1938 obj->symtab == NULL || obj->strtab == NULL) {
1939 _rtld_error("%s: Shared object has no run-time symbol table",
1945 /* There are relocations to the write-protected text segment. */
1946 if (mprotect(obj->mapbase, obj->textsize,
1947 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
1948 _rtld_error("%s: Cannot write-enable text segment: %s",
1949 obj->path, strerror(errno));
1954 /* Process the non-PLT relocations. */
1955 if (reloc_non_plt(obj, rtldobj, lockstate))
1958 if (obj->textrel) { /* Re-protected the text segment. */
1959 if (mprotect(obj->mapbase, obj->textsize,
1960 PROT_READ|PROT_EXEC) == -1) {
1961 _rtld_error("%s: Cannot write-protect text segment: %s",
1962 obj->path, strerror(errno));
1968 /* Set the special PLT or GOT entries. */
1971 /* Process the PLT relocations. */
1972 if (reloc_plt(obj) == -1)
1974 /* Relocate the jump slots if we are doing immediate binding. */
1975 if (obj->bind_now || bind_now)
1976 if (reloc_jmpslots(obj, lockstate) == -1)
1980 * Set up the magic number and version in the Obj_Entry. These
1981 * were checked in the crt1.o from the original ElfKit, so we
1982 * set them for backward compatibility.
1984 obj->magic = RTLD_MAGIC;
1985 obj->version = RTLD_VERSION;
1992 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
1993 * referencing STT_GNU_IFUNC symbols is postponed till the other
1994 * relocations are done. The indirect functions specified as
1995 * ifunc are allowed to call other symbols, so we need to have
1996 * objects relocated before asking for resolution from indirects.
1998 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
1999 * instead of the usual lazy handling of PLT slots. It is
2000 * consistent with how GNU does it.
2003 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, RtldLockState *lockstate)
2005 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2007 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2008 reloc_gnu_ifunc(obj, lockstate) == -1)
2014 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, RtldLockState *lockstate)
2018 for (obj = first; obj != NULL; obj = obj->next) {
2019 if (resolve_object_ifunc(obj, bind_now, lockstate) == -1)
2026 initlist_objects_ifunc(Objlist *list, bool bind_now, RtldLockState *lockstate)
2030 STAILQ_FOREACH(elm, list, link) {
2031 if (resolve_object_ifunc(elm->obj, bind_now, lockstate) == -1)
2038 * Cleanup procedure. It will be called (by the atexit mechanism) just
2039 * before the process exits.
2044 RtldLockState lockstate;
2046 wlock_acquire(rtld_bind_lock, &lockstate);
2048 objlist_call_fini(&list_fini, NULL, &lockstate);
2049 /* No need to remove the items from the list, since we are exiting. */
2050 if (!libmap_disable)
2052 lock_release(rtld_bind_lock, &lockstate);
2056 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2064 path += strspn(path, ":;");
2065 while (*path != '\0') {
2069 len = strcspn(path, ":;");
2071 trans = lm_findn(NULL, path, len);
2073 res = callback(trans, strlen(trans), arg);
2076 res = callback(path, len, arg);
2082 path += strspn(path, ":;");
2088 struct try_library_args {
2096 try_library_path(const char *dir, size_t dirlen, void *param)
2098 struct try_library_args *arg;
2101 if (*dir == '/' || trust) {
2104 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2107 pathname = arg->buffer;
2108 strncpy(pathname, dir, dirlen);
2109 pathname[dirlen] = '/';
2110 strcpy(pathname + dirlen + 1, arg->name);
2112 dbg(" Trying \"%s\"", pathname);
2113 if (access(pathname, F_OK) == 0) { /* We found it */
2114 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2115 strcpy(pathname, arg->buffer);
2123 search_library_path(const char *name, const char *path)
2126 struct try_library_args arg;
2132 arg.namelen = strlen(name);
2133 arg.buffer = xmalloc(PATH_MAX);
2134 arg.buflen = PATH_MAX;
2136 p = path_enumerate(path, try_library_path, &arg);
2144 dlclose(void *handle)
2147 RtldLockState lockstate;
2149 wlock_acquire(rtld_bind_lock, &lockstate);
2150 root = dlcheck(handle);
2152 lock_release(rtld_bind_lock, &lockstate);
2155 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2158 /* Unreference the object and its dependencies. */
2159 root->dl_refcount--;
2161 if (root->refcount == 1) {
2163 * The object will be no longer referenced, so we must unload it.
2164 * First, call the fini functions.
2166 objlist_call_fini(&list_fini, root, &lockstate);
2170 /* Finish cleaning up the newly-unreferenced objects. */
2171 GDB_STATE(RT_DELETE,&root->linkmap);
2172 unload_object(root);
2173 GDB_STATE(RT_CONSISTENT,NULL);
2177 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2178 lock_release(rtld_bind_lock, &lockstate);
2185 char *msg = error_message;
2186 error_message = NULL;
2191 * This function is deprecated and has no effect.
2194 dllockinit(void *context,
2195 void *(*lock_create)(void *context),
2196 void (*rlock_acquire)(void *lock),
2197 void (*wlock_acquire)(void *lock),
2198 void (*lock_release)(void *lock),
2199 void (*lock_destroy)(void *lock),
2200 void (*context_destroy)(void *context))
2202 static void *cur_context;
2203 static void (*cur_context_destroy)(void *);
2205 /* Just destroy the context from the previous call, if necessary. */
2206 if (cur_context_destroy != NULL)
2207 cur_context_destroy(cur_context);
2208 cur_context = context;
2209 cur_context_destroy = context_destroy;
2213 dlopen(const char *name, int mode)
2215 RtldLockState lockstate;
2218 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2219 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2220 if (ld_tracing != NULL) {
2221 rlock_acquire(rtld_bind_lock, &lockstate);
2222 if (sigsetjmp(lockstate.env, 0) != 0)
2223 lock_upgrade(rtld_bind_lock, &lockstate);
2224 environ = (char **)*get_program_var_addr("environ", &lockstate);
2225 lock_release(rtld_bind_lock, &lockstate);
2227 lo_flags = RTLD_LO_DLOPEN;
2228 if (mode & RTLD_NODELETE)
2229 lo_flags |= RTLD_LO_NODELETE;
2230 if (mode & RTLD_NOLOAD)
2231 lo_flags |= RTLD_LO_NOLOAD;
2232 if (ld_tracing != NULL)
2233 lo_flags |= RTLD_LO_TRACE;
2235 return (dlopen_object(name, obj_main, lo_flags,
2236 mode & (RTLD_MODEMASK | RTLD_GLOBAL)));
2240 dlopen_cleanup(Obj_Entry *obj)
2245 if (obj->refcount == 0)
2250 dlopen_object(const char *name, Obj_Entry *refobj, int lo_flags, int mode)
2252 Obj_Entry **old_obj_tail;
2255 RtldLockState lockstate;
2258 objlist_init(&initlist);
2260 wlock_acquire(rtld_bind_lock, &lockstate);
2261 GDB_STATE(RT_ADD,NULL);
2263 old_obj_tail = obj_tail;
2269 obj = load_object(name, refobj, lo_flags);
2274 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2275 objlist_push_tail(&list_global, obj);
2276 if (*old_obj_tail != NULL) { /* We loaded something new. */
2277 assert(*old_obj_tail == obj);
2278 result = load_needed_objects(obj, lo_flags & RTLD_LO_DLOPEN);
2282 result = rtld_verify_versions(&obj->dagmembers);
2283 if (result != -1 && ld_tracing)
2285 if (result == -1 || (relocate_objects(obj, (mode & RTLD_MODEMASK)
2286 == RTLD_NOW, &obj_rtld, &lockstate)) == -1) {
2287 dlopen_cleanup(obj);
2290 /* Make list of init functions to call. */
2291 initlist_add_objects(obj, &obj->next, &initlist);
2296 * Bump the reference counts for objects on this DAG. If
2297 * this is the first dlopen() call for the object that was
2298 * already loaded as a dependency, initialize the dag
2304 if ((lo_flags & RTLD_LO_TRACE) != 0)
2307 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2308 obj->z_nodelete) && !obj->ref_nodel) {
2309 dbg("obj %s nodelete", obj->path);
2311 obj->z_nodelete = obj->ref_nodel = true;
2315 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2317 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2319 map_stacks_exec(&lockstate);
2321 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
2322 &lockstate) == -1) {
2323 objlist_clear(&initlist);
2324 dlopen_cleanup(obj);
2325 lock_release(rtld_bind_lock, &lockstate);
2329 /* Call the init functions. */
2330 objlist_call_init(&initlist, &lockstate);
2331 objlist_clear(&initlist);
2332 lock_release(rtld_bind_lock, &lockstate);
2335 trace_loaded_objects(obj);
2336 lock_release(rtld_bind_lock, &lockstate);
2341 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
2345 const Obj_Entry *obj, *defobj;
2348 RtldLockState lockstate;
2353 symlook_init(&req, name);
2355 req.flags = flags | SYMLOOK_IN_PLT;
2356 req.lockstate = &lockstate;
2358 rlock_acquire(rtld_bind_lock, &lockstate);
2359 if (sigsetjmp(lockstate.env, 0) != 0)
2360 lock_upgrade(rtld_bind_lock, &lockstate);
2361 if (handle == NULL || handle == RTLD_NEXT ||
2362 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
2364 if ((obj = obj_from_addr(retaddr)) == NULL) {
2365 _rtld_error("Cannot determine caller's shared object");
2366 lock_release(rtld_bind_lock, &lockstate);
2369 if (handle == NULL) { /* Just the caller's shared object. */
2370 res = symlook_obj(&req, obj);
2373 defobj = req.defobj_out;
2375 } else if (handle == RTLD_NEXT || /* Objects after caller's */
2376 handle == RTLD_SELF) { /* ... caller included */
2377 if (handle == RTLD_NEXT)
2379 for (; obj != NULL; obj = obj->next) {
2380 res = symlook_obj(&req, obj);
2383 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
2385 defobj = req.defobj_out;
2386 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
2392 * Search the dynamic linker itself, and possibly resolve the
2393 * symbol from there. This is how the application links to
2394 * dynamic linker services such as dlopen.
2396 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2397 res = symlook_obj(&req, &obj_rtld);
2400 defobj = req.defobj_out;
2404 assert(handle == RTLD_DEFAULT);
2405 res = symlook_default(&req, obj);
2407 defobj = req.defobj_out;
2412 if ((obj = dlcheck(handle)) == NULL) {
2413 lock_release(rtld_bind_lock, &lockstate);
2417 donelist_init(&donelist);
2418 if (obj->mainprog) {
2419 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
2420 res = symlook_global(&req, &donelist);
2423 defobj = req.defobj_out;
2426 * Search the dynamic linker itself, and possibly resolve the
2427 * symbol from there. This is how the application links to
2428 * dynamic linker services such as dlopen.
2430 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2431 res = symlook_obj(&req, &obj_rtld);
2434 defobj = req.defobj_out;
2439 /* Search the whole DAG rooted at the given object. */
2440 res = symlook_list(&req, &obj->dagmembers, &donelist);
2443 defobj = req.defobj_out;
2449 lock_release(rtld_bind_lock, &lockstate);
2452 * The value required by the caller is derived from the value
2453 * of the symbol. For the ia64 architecture, we need to
2454 * construct a function descriptor which the caller can use to
2455 * call the function with the right 'gp' value. For other
2456 * architectures and for non-functions, the value is simply
2457 * the relocated value of the symbol.
2459 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
2460 return (make_function_pointer(def, defobj));
2461 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
2462 return (rtld_resolve_ifunc(defobj, def));
2464 return (defobj->relocbase + def->st_value);
2467 _rtld_error("Undefined symbol \"%s\"", name);
2468 lock_release(rtld_bind_lock, &lockstate);
2473 dlsym(void *handle, const char *name)
2475 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
2480 dlfunc(void *handle, const char *name)
2487 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
2493 dlvsym(void *handle, const char *name, const char *version)
2497 ventry.name = version;
2499 ventry.hash = elf_hash(version);
2501 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
2506 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
2508 const Obj_Entry *obj;
2509 RtldLockState lockstate;
2511 rlock_acquire(rtld_bind_lock, &lockstate);
2512 obj = obj_from_addr(addr);
2514 _rtld_error("No shared object contains address");
2515 lock_release(rtld_bind_lock, &lockstate);
2518 rtld_fill_dl_phdr_info(obj, phdr_info);
2519 lock_release(rtld_bind_lock, &lockstate);
2524 dladdr(const void *addr, Dl_info *info)
2526 const Obj_Entry *obj;
2529 unsigned long symoffset;
2530 RtldLockState lockstate;
2532 rlock_acquire(rtld_bind_lock, &lockstate);
2533 obj = obj_from_addr(addr);
2535 _rtld_error("No shared object contains address");
2536 lock_release(rtld_bind_lock, &lockstate);
2539 info->dli_fname = obj->path;
2540 info->dli_fbase = obj->mapbase;
2541 info->dli_saddr = (void *)0;
2542 info->dli_sname = NULL;
2545 * Walk the symbol list looking for the symbol whose address is
2546 * closest to the address sent in.
2548 for (symoffset = 0; symoffset < obj->nchains; symoffset++) {
2549 def = obj->symtab + symoffset;
2552 * For skip the symbol if st_shndx is either SHN_UNDEF or
2555 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
2559 * If the symbol is greater than the specified address, or if it
2560 * is further away from addr than the current nearest symbol,
2563 symbol_addr = obj->relocbase + def->st_value;
2564 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
2567 /* Update our idea of the nearest symbol. */
2568 info->dli_sname = obj->strtab + def->st_name;
2569 info->dli_saddr = symbol_addr;
2572 if (info->dli_saddr == addr)
2575 lock_release(rtld_bind_lock, &lockstate);
2580 dlinfo(void *handle, int request, void *p)
2582 const Obj_Entry *obj;
2583 RtldLockState lockstate;
2586 rlock_acquire(rtld_bind_lock, &lockstate);
2588 if (handle == NULL || handle == RTLD_SELF) {
2591 retaddr = __builtin_return_address(0); /* __GNUC__ only */
2592 if ((obj = obj_from_addr(retaddr)) == NULL)
2593 _rtld_error("Cannot determine caller's shared object");
2595 obj = dlcheck(handle);
2598 lock_release(rtld_bind_lock, &lockstate);
2604 case RTLD_DI_LINKMAP:
2605 *((struct link_map const **)p) = &obj->linkmap;
2607 case RTLD_DI_ORIGIN:
2608 error = rtld_dirname(obj->path, p);
2611 case RTLD_DI_SERINFOSIZE:
2612 case RTLD_DI_SERINFO:
2613 error = do_search_info(obj, request, (struct dl_serinfo *)p);
2617 _rtld_error("Invalid request %d passed to dlinfo()", request);
2621 lock_release(rtld_bind_lock, &lockstate);
2627 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
2630 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
2631 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
2632 STAILQ_FIRST(&obj->names)->name : obj->path;
2633 phdr_info->dlpi_phdr = obj->phdr;
2634 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
2635 phdr_info->dlpi_tls_modid = obj->tlsindex;
2636 phdr_info->dlpi_tls_data = obj->tlsinit;
2637 phdr_info->dlpi_adds = obj_loads;
2638 phdr_info->dlpi_subs = obj_loads - obj_count;
2642 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
2644 struct dl_phdr_info phdr_info;
2645 const Obj_Entry *obj;
2646 RtldLockState bind_lockstate, phdr_lockstate;
2649 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
2650 rlock_acquire(rtld_bind_lock, &bind_lockstate);
2654 for (obj = obj_list; obj != NULL; obj = obj->next) {
2655 rtld_fill_dl_phdr_info(obj, &phdr_info);
2656 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
2660 lock_release(rtld_bind_lock, &bind_lockstate);
2661 lock_release(rtld_phdr_lock, &phdr_lockstate);
2666 struct fill_search_info_args {
2669 Dl_serinfo *serinfo;
2670 Dl_serpath *serpath;
2675 fill_search_info(const char *dir, size_t dirlen, void *param)
2677 struct fill_search_info_args *arg;
2681 if (arg->request == RTLD_DI_SERINFOSIZE) {
2682 arg->serinfo->dls_cnt ++;
2683 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1;
2685 struct dl_serpath *s_entry;
2687 s_entry = arg->serpath;
2688 s_entry->dls_name = arg->strspace;
2689 s_entry->dls_flags = arg->flags;
2691 strncpy(arg->strspace, dir, dirlen);
2692 arg->strspace[dirlen] = '\0';
2694 arg->strspace += dirlen + 1;
2702 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
2704 struct dl_serinfo _info;
2705 struct fill_search_info_args args;
2707 args.request = RTLD_DI_SERINFOSIZE;
2708 args.serinfo = &_info;
2710 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2713 path_enumerate(ld_library_path, fill_search_info, &args);
2714 path_enumerate(obj->rpath, fill_search_info, &args);
2715 path_enumerate(gethints(), fill_search_info, &args);
2716 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
2719 if (request == RTLD_DI_SERINFOSIZE) {
2720 info->dls_size = _info.dls_size;
2721 info->dls_cnt = _info.dls_cnt;
2725 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
2726 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
2730 args.request = RTLD_DI_SERINFO;
2731 args.serinfo = info;
2732 args.serpath = &info->dls_serpath[0];
2733 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
2735 args.flags = LA_SER_LIBPATH;
2736 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
2739 args.flags = LA_SER_RUNPATH;
2740 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
2743 args.flags = LA_SER_CONFIG;
2744 if (path_enumerate(gethints(), fill_search_info, &args) != NULL)
2747 args.flags = LA_SER_DEFAULT;
2748 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
2754 rtld_dirname(const char *path, char *bname)
2758 /* Empty or NULL string gets treated as "." */
2759 if (path == NULL || *path == '\0') {
2765 /* Strip trailing slashes */
2766 endp = path + strlen(path) - 1;
2767 while (endp > path && *endp == '/')
2770 /* Find the start of the dir */
2771 while (endp > path && *endp != '/')
2774 /* Either the dir is "/" or there are no slashes */
2776 bname[0] = *endp == '/' ? '/' : '.';
2782 } while (endp > path && *endp == '/');
2785 if (endp - path + 2 > PATH_MAX)
2787 _rtld_error("Filename is too long: %s", path);
2791 strncpy(bname, path, endp - path + 1);
2792 bname[endp - path + 1] = '\0';
2797 rtld_dirname_abs(const char *path, char *base)
2799 char base_rel[PATH_MAX];
2801 if (rtld_dirname(path, base) == -1)
2805 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
2806 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
2807 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
2809 strcpy(base, base_rel);
2814 linkmap_add(Obj_Entry *obj)
2816 struct link_map *l = &obj->linkmap;
2817 struct link_map *prev;
2819 obj->linkmap.l_name = obj->path;
2820 obj->linkmap.l_addr = obj->mapbase;
2821 obj->linkmap.l_ld = obj->dynamic;
2823 /* GDB needs load offset on MIPS to use the symbols */
2824 obj->linkmap.l_offs = obj->relocbase;
2827 if (r_debug.r_map == NULL) {
2833 * Scan to the end of the list, but not past the entry for the
2834 * dynamic linker, which we want to keep at the very end.
2836 for (prev = r_debug.r_map;
2837 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
2838 prev = prev->l_next)
2841 /* Link in the new entry. */
2843 l->l_next = prev->l_next;
2844 if (l->l_next != NULL)
2845 l->l_next->l_prev = l;
2850 linkmap_delete(Obj_Entry *obj)
2852 struct link_map *l = &obj->linkmap;
2854 if (l->l_prev == NULL) {
2855 if ((r_debug.r_map = l->l_next) != NULL)
2856 l->l_next->l_prev = NULL;
2860 if ((l->l_prev->l_next = l->l_next) != NULL)
2861 l->l_next->l_prev = l->l_prev;
2865 * Function for the debugger to set a breakpoint on to gain control.
2867 * The two parameters allow the debugger to easily find and determine
2868 * what the runtime loader is doing and to whom it is doing it.
2870 * When the loadhook trap is hit (r_debug_state, set at program
2871 * initialization), the arguments can be found on the stack:
2873 * +8 struct link_map *m
2874 * +4 struct r_debug *rd
2878 r_debug_state(struct r_debug* rd, struct link_map *m)
2881 * The following is a hack to force the compiler to emit calls to
2882 * this function, even when optimizing. If the function is empty,
2883 * the compiler is not obliged to emit any code for calls to it,
2884 * even when marked __noinline. However, gdb depends on those
2887 __asm __volatile("" : : : "memory");
2891 * Get address of the pointer variable in the main program.
2892 * Prefer non-weak symbol over the weak one.
2894 static const void **
2895 get_program_var_addr(const char *name, RtldLockState *lockstate)
2900 symlook_init(&req, name);
2901 req.lockstate = lockstate;
2902 donelist_init(&donelist);
2903 if (symlook_global(&req, &donelist) != 0)
2905 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
2906 return ((const void **)make_function_pointer(req.sym_out,
2908 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
2909 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
2911 return ((const void **)(req.defobj_out->relocbase +
2912 req.sym_out->st_value));
2916 * Set a pointer variable in the main program to the given value. This
2917 * is used to set key variables such as "environ" before any of the
2918 * init functions are called.
2921 set_program_var(const char *name, const void *value)
2925 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
2926 dbg("\"%s\": *%p <-- %p", name, addr, value);
2932 * Search the global objects, including dependencies and main object,
2933 * for the given symbol.
2936 symlook_global(SymLook *req, DoneList *donelist)
2939 const Objlist_Entry *elm;
2942 symlook_init_from_req(&req1, req);
2944 /* Search all objects loaded at program start up. */
2945 if (req->defobj_out == NULL ||
2946 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
2947 res = symlook_list(&req1, &list_main, donelist);
2948 if (res == 0 && (req->defobj_out == NULL ||
2949 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
2950 req->sym_out = req1.sym_out;
2951 req->defobj_out = req1.defobj_out;
2952 assert(req->defobj_out != NULL);
2956 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
2957 STAILQ_FOREACH(elm, &list_global, link) {
2958 if (req->defobj_out != NULL &&
2959 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
2961 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
2962 if (res == 0 && (req->defobj_out == NULL ||
2963 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
2964 req->sym_out = req1.sym_out;
2965 req->defobj_out = req1.defobj_out;
2966 assert(req->defobj_out != NULL);
2970 return (req->sym_out != NULL ? 0 : ESRCH);
2974 * Given a symbol name in a referencing object, find the corresponding
2975 * definition of the symbol. Returns a pointer to the symbol, or NULL if
2976 * no definition was found. Returns a pointer to the Obj_Entry of the
2977 * defining object via the reference parameter DEFOBJ_OUT.
2980 symlook_default(SymLook *req, const Obj_Entry *refobj)
2983 const Objlist_Entry *elm;
2987 donelist_init(&donelist);
2988 symlook_init_from_req(&req1, req);
2990 /* Look first in the referencing object if linked symbolically. */
2991 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
2992 res = symlook_obj(&req1, refobj);
2994 req->sym_out = req1.sym_out;
2995 req->defobj_out = req1.defobj_out;
2996 assert(req->defobj_out != NULL);
3000 symlook_global(req, &donelist);
3002 /* Search all dlopened DAGs containing the referencing object. */
3003 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3004 if (req->sym_out != NULL &&
3005 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3007 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3008 if (res == 0 && (req->sym_out == NULL ||
3009 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3010 req->sym_out = req1.sym_out;
3011 req->defobj_out = req1.defobj_out;
3012 assert(req->defobj_out != NULL);
3017 * Search the dynamic linker itself, and possibly resolve the
3018 * symbol from there. This is how the application links to
3019 * dynamic linker services such as dlopen.
3021 if (req->sym_out == NULL ||
3022 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3023 res = symlook_obj(&req1, &obj_rtld);
3025 req->sym_out = req1.sym_out;
3026 req->defobj_out = req1.defobj_out;
3027 assert(req->defobj_out != NULL);
3031 return (req->sym_out != NULL ? 0 : ESRCH);
3035 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3038 const Obj_Entry *defobj;
3039 const Objlist_Entry *elm;
3045 STAILQ_FOREACH(elm, objlist, link) {
3046 if (donelist_check(dlp, elm->obj))
3048 symlook_init_from_req(&req1, req);
3049 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3050 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3052 defobj = req1.defobj_out;
3053 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3060 req->defobj_out = defobj;
3067 * Search the chain of DAGS cointed to by the given Needed_Entry
3068 * for a symbol of the given name. Each DAG is scanned completely
3069 * before advancing to the next one. Returns a pointer to the symbol,
3070 * or NULL if no definition was found.
3073 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3076 const Needed_Entry *n;
3077 const Obj_Entry *defobj;
3083 symlook_init_from_req(&req1, req);
3084 for (n = needed; n != NULL; n = n->next) {
3085 if (n->obj == NULL ||
3086 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3088 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3090 defobj = req1.defobj_out;
3091 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3097 req->defobj_out = defobj;
3104 * Search the symbol table of a single shared object for a symbol of
3105 * the given name and version, if requested. Returns a pointer to the
3106 * symbol, or NULL if no definition was found. If the object is
3107 * filter, return filtered symbol from filtee.
3109 * The symbol's hash value is passed in for efficiency reasons; that
3110 * eliminates many recomputations of the hash value.
3113 symlook_obj(SymLook *req, const Obj_Entry *obj)
3119 mres = symlook_obj1(req, obj);
3121 if (obj->needed_filtees != NULL) {
3122 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate);
3123 donelist_init(&donelist);
3124 symlook_init_from_req(&req1, req);
3125 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3127 req->sym_out = req1.sym_out;
3128 req->defobj_out = req1.defobj_out;
3132 if (obj->needed_aux_filtees != NULL) {
3133 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate);
3134 donelist_init(&donelist);
3135 symlook_init_from_req(&req1, req);
3136 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3138 req->sym_out = req1.sym_out;
3139 req->defobj_out = req1.defobj_out;
3148 symlook_obj1(SymLook *req, const Obj_Entry *obj)
3150 unsigned long symnum;
3151 const Elf_Sym *vsymp;
3155 if (obj->buckets == NULL)
3160 symnum = obj->buckets[req->hash % obj->nbuckets];
3162 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
3163 const Elf_Sym *symp;
3166 if (symnum >= obj->nchains)
3167 return (ESRCH); /* Bad object */
3169 symp = obj->symtab + symnum;
3170 strp = obj->strtab + symp->st_name;
3172 switch (ELF_ST_TYPE(symp->st_info)) {
3177 if (symp->st_value == 0)
3181 if (symp->st_shndx != SHN_UNDEF)
3184 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3185 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3192 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3195 if (req->ventry == NULL) {
3196 if (obj->versyms != NULL) {
3197 verndx = VER_NDX(obj->versyms[symnum]);
3198 if (verndx > obj->vernum) {
3199 _rtld_error("%s: symbol %s references wrong version %d",
3200 obj->path, obj->strtab + symnum, verndx);
3204 * If we are not called from dlsym (i.e. this is a normal
3205 * relocation from unversioned binary), accept the symbol
3206 * immediately if it happens to have first version after
3207 * this shared object became versioned. Otherwise, if
3208 * symbol is versioned and not hidden, remember it. If it
3209 * is the only symbol with this name exported by the
3210 * shared object, it will be returned as a match at the
3211 * end of the function. If symbol is global (verndx < 2)
3212 * accept it unconditionally.
3214 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3215 verndx == VER_NDX_GIVEN) {
3216 req->sym_out = symp;
3217 req->defobj_out = obj;
3220 else if (verndx >= VER_NDX_GIVEN) {
3221 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) {
3229 req->sym_out = symp;
3230 req->defobj_out = obj;
3233 if (obj->versyms == NULL) {
3234 if (object_match_name(obj, req->ventry->name)) {
3235 _rtld_error("%s: object %s should provide version %s for "
3236 "symbol %s", obj_rtld.path, obj->path,
3237 req->ventry->name, obj->strtab + symnum);
3241 verndx = VER_NDX(obj->versyms[symnum]);
3242 if (verndx > obj->vernum) {
3243 _rtld_error("%s: symbol %s references wrong version %d",
3244 obj->path, obj->strtab + symnum, verndx);
3247 if (obj->vertab[verndx].hash != req->ventry->hash ||
3248 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3250 * Version does not match. Look if this is a global symbol
3251 * and if it is not hidden. If global symbol (verndx < 2)
3252 * is available, use it. Do not return symbol if we are
3253 * called by dlvsym, because dlvsym looks for a specific
3254 * version and default one is not what dlvsym wants.
3256 if ((req->flags & SYMLOOK_DLSYM) ||
3257 (obj->versyms[symnum] & VER_NDX_HIDDEN) ||
3258 (verndx >= VER_NDX_GIVEN))
3262 req->sym_out = symp;
3263 req->defobj_out = obj;
3268 req->sym_out = vsymp;
3269 req->defobj_out = obj;
3276 trace_loaded_objects(Obj_Entry *obj)
3278 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
3281 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
3284 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
3285 fmt1 = "\t%o => %p (%x)\n";
3287 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
3288 fmt2 = "\t%o (%x)\n";
3290 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
3292 for (; obj; obj = obj->next) {
3293 Needed_Entry *needed;
3297 if (list_containers && obj->needed != NULL)
3298 rtld_printf("%s:\n", obj->path);
3299 for (needed = obj->needed; needed; needed = needed->next) {
3300 if (needed->obj != NULL) {
3301 if (needed->obj->traced && !list_containers)
3303 needed->obj->traced = true;
3304 path = needed->obj->path;
3308 name = (char *)obj->strtab + needed->name;
3309 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
3311 fmt = is_lib ? fmt1 : fmt2;
3312 while ((c = *fmt++) != '\0') {
3338 rtld_putstr(main_local);
3341 rtld_putstr(obj_main->path);
3348 rtld_printf("%d", sodp->sod_major);
3351 rtld_printf("%d", sodp->sod_minor);
3358 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
3371 * Unload a dlopened object and its dependencies from memory and from
3372 * our data structures. It is assumed that the DAG rooted in the
3373 * object has already been unreferenced, and that the object has a
3374 * reference count of 0.
3377 unload_object(Obj_Entry *root)
3382 assert(root->refcount == 0);
3385 * Pass over the DAG removing unreferenced objects from
3386 * appropriate lists.
3388 unlink_object(root);
3390 /* Unmap all objects that are no longer referenced. */
3391 linkp = &obj_list->next;
3392 while ((obj = *linkp) != NULL) {
3393 if (obj->refcount == 0) {
3394 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
3396 dbg("unloading \"%s\"", obj->path);
3397 unload_filtees(root);
3398 munmap(obj->mapbase, obj->mapsize);
3399 linkmap_delete(obj);
3410 unlink_object(Obj_Entry *root)
3414 if (root->refcount == 0) {
3415 /* Remove the object from the RTLD_GLOBAL list. */
3416 objlist_remove(&list_global, root);
3418 /* Remove the object from all objects' DAG lists. */
3419 STAILQ_FOREACH(elm, &root->dagmembers, link) {
3420 objlist_remove(&elm->obj->dldags, root);
3421 if (elm->obj != root)
3422 unlink_object(elm->obj);
3428 ref_dag(Obj_Entry *root)
3432 assert(root->dag_inited);
3433 STAILQ_FOREACH(elm, &root->dagmembers, link)
3434 elm->obj->refcount++;
3438 unref_dag(Obj_Entry *root)
3442 assert(root->dag_inited);
3443 STAILQ_FOREACH(elm, &root->dagmembers, link)
3444 elm->obj->refcount--;
3448 * Common code for MD __tls_get_addr().
3451 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset)
3453 Elf_Addr* dtv = *dtvp;
3454 RtldLockState lockstate;
3456 /* Check dtv generation in case new modules have arrived */
3457 if (dtv[0] != tls_dtv_generation) {
3461 wlock_acquire(rtld_bind_lock, &lockstate);
3462 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
3464 if (to_copy > tls_max_index)
3465 to_copy = tls_max_index;
3466 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
3467 newdtv[0] = tls_dtv_generation;
3468 newdtv[1] = tls_max_index;
3470 lock_release(rtld_bind_lock, &lockstate);
3471 dtv = *dtvp = newdtv;
3474 /* Dynamically allocate module TLS if necessary */
3475 if (!dtv[index + 1]) {
3476 /* Signal safe, wlock will block out signals. */
3477 wlock_acquire(rtld_bind_lock, &lockstate);
3478 if (!dtv[index + 1])
3479 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
3480 lock_release(rtld_bind_lock, &lockstate);
3482 return (void*) (dtv[index + 1] + offset);
3485 /* XXX not sure what variants to use for arm. */
3487 #if defined(__ia64__) || defined(__powerpc__)
3490 * Allocate Static TLS using the Variant I method.
3493 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
3502 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
3505 assert(tcbsize >= TLS_TCB_SIZE);
3506 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
3507 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
3509 if (oldtcb != NULL) {
3510 memcpy(tls, oldtcb, tls_static_space);
3513 /* Adjust the DTV. */
3515 for (i = 0; i < dtv[1]; i++) {
3516 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
3517 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
3518 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
3522 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr));
3524 dtv[0] = tls_dtv_generation;
3525 dtv[1] = tls_max_index;
3527 for (obj = objs; obj; obj = obj->next) {
3528 if (obj->tlsoffset > 0) {
3529 addr = (Elf_Addr)tls + obj->tlsoffset;
3530 if (obj->tlsinitsize > 0)
3531 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
3532 if (obj->tlssize > obj->tlsinitsize)
3533 memset((void*) (addr + obj->tlsinitsize), 0,
3534 obj->tlssize - obj->tlsinitsize);
3535 dtv[obj->tlsindex + 1] = addr;
3544 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
3547 Elf_Addr tlsstart, tlsend;
3550 assert(tcbsize >= TLS_TCB_SIZE);
3552 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
3553 tlsend = tlsstart + tls_static_space;
3555 dtv = *(Elf_Addr **)tlsstart;
3557 for (i = 0; i < dtvsize; i++) {
3558 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
3559 free((void*)dtv[i+2]);
3568 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \
3569 defined(__arm__) || defined(__mips__)
3572 * Allocate Static TLS using the Variant II method.
3575 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
3580 Elf_Addr *dtv, *olddtv;
3581 Elf_Addr segbase, oldsegbase, addr;
3584 size = round(tls_static_space, tcbalign);
3586 assert(tcbsize >= 2*sizeof(Elf_Addr));
3587 tls = calloc(1, size + tcbsize);
3588 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
3590 segbase = (Elf_Addr)(tls + size);
3591 ((Elf_Addr*)segbase)[0] = segbase;
3592 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
3594 dtv[0] = tls_dtv_generation;
3595 dtv[1] = tls_max_index;
3599 * Copy the static TLS block over whole.
3601 oldsegbase = (Elf_Addr) oldtls;
3602 memcpy((void *)(segbase - tls_static_space),
3603 (const void *)(oldsegbase - tls_static_space),
3607 * If any dynamic TLS blocks have been created tls_get_addr(),
3610 olddtv = ((Elf_Addr**)oldsegbase)[1];
3611 for (i = 0; i < olddtv[1]; i++) {
3612 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
3613 dtv[i+2] = olddtv[i+2];
3619 * We assume that this block was the one we created with
3620 * allocate_initial_tls().
3622 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
3624 for (obj = objs; obj; obj = obj->next) {
3625 if (obj->tlsoffset) {
3626 addr = segbase - obj->tlsoffset;
3627 memset((void*) (addr + obj->tlsinitsize),
3628 0, obj->tlssize - obj->tlsinitsize);
3630 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
3631 dtv[obj->tlsindex + 1] = addr;
3636 return (void*) segbase;
3640 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
3645 Elf_Addr tlsstart, tlsend;
3648 * Figure out the size of the initial TLS block so that we can
3649 * find stuff which ___tls_get_addr() allocated dynamically.
3651 size = round(tls_static_space, tcbalign);
3653 dtv = ((Elf_Addr**)tls)[1];
3655 tlsend = (Elf_Addr) tls;
3656 tlsstart = tlsend - size;
3657 for (i = 0; i < dtvsize; i++) {
3658 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) {
3659 free((void*) dtv[i+2]);
3663 free((void*) tlsstart);
3670 * Allocate TLS block for module with given index.
3673 allocate_module_tls(int index)
3678 for (obj = obj_list; obj; obj = obj->next) {
3679 if (obj->tlsindex == index)
3683 _rtld_error("Can't find module with TLS index %d", index);
3687 p = malloc(obj->tlssize);
3689 _rtld_error("Cannot allocate TLS block for index %d", index);
3692 memcpy(p, obj->tlsinit, obj->tlsinitsize);
3693 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
3699 allocate_tls_offset(Obj_Entry *obj)
3706 if (obj->tlssize == 0) {
3707 obj->tls_done = true;
3711 if (obj->tlsindex == 1)
3712 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
3714 off = calculate_tls_offset(tls_last_offset, tls_last_size,
3715 obj->tlssize, obj->tlsalign);
3718 * If we have already fixed the size of the static TLS block, we
3719 * must stay within that size. When allocating the static TLS, we
3720 * leave a small amount of space spare to be used for dynamically
3721 * loading modules which use static TLS.
3723 if (tls_static_space) {
3724 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
3728 tls_last_offset = obj->tlsoffset = off;
3729 tls_last_size = obj->tlssize;
3730 obj->tls_done = true;
3736 free_tls_offset(Obj_Entry *obj)
3740 * If we were the last thing to allocate out of the static TLS
3741 * block, we give our space back to the 'allocator'. This is a
3742 * simplistic workaround to allow libGL.so.1 to be loaded and
3743 * unloaded multiple times.
3745 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
3746 == calculate_tls_end(tls_last_offset, tls_last_size)) {
3747 tls_last_offset -= obj->tlssize;
3753 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
3756 RtldLockState lockstate;
3758 wlock_acquire(rtld_bind_lock, &lockstate);
3759 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
3760 lock_release(rtld_bind_lock, &lockstate);
3765 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
3767 RtldLockState lockstate;
3769 wlock_acquire(rtld_bind_lock, &lockstate);
3770 free_tls(tcb, tcbsize, tcbalign);
3771 lock_release(rtld_bind_lock, &lockstate);
3775 object_add_name(Obj_Entry *obj, const char *name)
3781 entry = malloc(sizeof(Name_Entry) + len);
3783 if (entry != NULL) {
3784 strcpy(entry->name, name);
3785 STAILQ_INSERT_TAIL(&obj->names, entry, link);
3790 object_match_name(const Obj_Entry *obj, const char *name)
3794 STAILQ_FOREACH(entry, &obj->names, link) {
3795 if (strcmp(name, entry->name) == 0)
3802 locate_dependency(const Obj_Entry *obj, const char *name)
3804 const Objlist_Entry *entry;
3805 const Needed_Entry *needed;
3807 STAILQ_FOREACH(entry, &list_main, link) {
3808 if (object_match_name(entry->obj, name))
3812 for (needed = obj->needed; needed != NULL; needed = needed->next) {
3813 if (strcmp(obj->strtab + needed->name, name) == 0 ||
3814 (needed->obj != NULL && object_match_name(needed->obj, name))) {
3816 * If there is DT_NEEDED for the name we are looking for,
3817 * we are all set. Note that object might not be found if
3818 * dependency was not loaded yet, so the function can
3819 * return NULL here. This is expected and handled
3820 * properly by the caller.
3822 return (needed->obj);
3825 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
3831 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
3832 const Elf_Vernaux *vna)
3834 const Elf_Verdef *vd;
3835 const char *vername;
3837 vername = refobj->strtab + vna->vna_name;
3838 vd = depobj->verdef;
3840 _rtld_error("%s: version %s required by %s not defined",
3841 depobj->path, vername, refobj->path);
3845 if (vd->vd_version != VER_DEF_CURRENT) {
3846 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
3847 depobj->path, vd->vd_version);
3850 if (vna->vna_hash == vd->vd_hash) {
3851 const Elf_Verdaux *aux = (const Elf_Verdaux *)
3852 ((char *)vd + vd->vd_aux);
3853 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
3856 if (vd->vd_next == 0)
3858 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3860 if (vna->vna_flags & VER_FLG_WEAK)
3862 _rtld_error("%s: version %s required by %s not found",
3863 depobj->path, vername, refobj->path);
3868 rtld_verify_object_versions(Obj_Entry *obj)
3870 const Elf_Verneed *vn;
3871 const Elf_Verdef *vd;
3872 const Elf_Verdaux *vda;
3873 const Elf_Vernaux *vna;
3874 const Obj_Entry *depobj;
3875 int maxvernum, vernum;
3879 * Walk over defined and required version records and figure out
3880 * max index used by any of them. Do very basic sanity checking
3884 while (vn != NULL) {
3885 if (vn->vn_version != VER_NEED_CURRENT) {
3886 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
3887 obj->path, vn->vn_version);
3890 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
3892 vernum = VER_NEED_IDX(vna->vna_other);
3893 if (vernum > maxvernum)
3895 if (vna->vna_next == 0)
3897 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
3899 if (vn->vn_next == 0)
3901 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
3905 while (vd != NULL) {
3906 if (vd->vd_version != VER_DEF_CURRENT) {
3907 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
3908 obj->path, vd->vd_version);
3911 vernum = VER_DEF_IDX(vd->vd_ndx);
3912 if (vernum > maxvernum)
3914 if (vd->vd_next == 0)
3916 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3923 * Store version information in array indexable by version index.
3924 * Verify that object version requirements are satisfied along the
3927 obj->vernum = maxvernum + 1;
3928 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry));
3931 while (vd != NULL) {
3932 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
3933 vernum = VER_DEF_IDX(vd->vd_ndx);
3934 assert(vernum <= maxvernum);
3935 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
3936 obj->vertab[vernum].hash = vd->vd_hash;
3937 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
3938 obj->vertab[vernum].file = NULL;
3939 obj->vertab[vernum].flags = 0;
3941 if (vd->vd_next == 0)
3943 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3947 while (vn != NULL) {
3948 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
3951 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
3953 if (check_object_provided_version(obj, depobj, vna))
3955 vernum = VER_NEED_IDX(vna->vna_other);
3956 assert(vernum <= maxvernum);
3957 obj->vertab[vernum].hash = vna->vna_hash;
3958 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
3959 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
3960 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
3961 VER_INFO_HIDDEN : 0;
3962 if (vna->vna_next == 0)
3964 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
3966 if (vn->vn_next == 0)
3968 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
3974 rtld_verify_versions(const Objlist *objlist)
3976 Objlist_Entry *entry;
3980 STAILQ_FOREACH(entry, objlist, link) {
3982 * Skip dummy objects or objects that have their version requirements
3985 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
3987 if (rtld_verify_object_versions(entry->obj) == -1) {
3989 if (ld_tracing == NULL)
3993 if (rc == 0 || ld_tracing != NULL)
3994 rc = rtld_verify_object_versions(&obj_rtld);
3999 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4004 vernum = VER_NDX(obj->versyms[symnum]);
4005 if (vernum >= obj->vernum) {
4006 _rtld_error("%s: symbol %s has wrong verneed value %d",
4007 obj->path, obj->strtab + symnum, vernum);
4008 } else if (obj->vertab[vernum].hash != 0) {
4009 return &obj->vertab[vernum];
4016 _rtld_get_stack_prot(void)
4019 return (stack_prot);
4023 map_stacks_exec(RtldLockState *lockstate)
4025 void (*thr_map_stacks_exec)(void);
4027 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4029 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4030 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4031 if (thr_map_stacks_exec != NULL) {
4032 stack_prot |= PROT_EXEC;
4033 thr_map_stacks_exec();
4038 symlook_init(SymLook *dst, const char *name)
4041 bzero(dst, sizeof(*dst));
4043 dst->hash = elf_hash(name);
4047 symlook_init_from_req(SymLook *dst, const SymLook *src)
4050 dst->name = src->name;
4051 dst->hash = src->hash;
4052 dst->ventry = src->ventry;
4053 dst->flags = src->flags;
4054 dst->defobj_out = NULL;
4055 dst->sym_out = NULL;
4056 dst->lockstate = src->lockstate;
4060 * Overrides for libc_pic-provided functions.
4064 __getosreldate(void)
4074 oid[1] = KERN_OSRELDATE;
4076 len = sizeof(osrel);
4077 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4078 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4084 * No unresolved symbols for rtld.
4087 __pthread_cxa_finalize(struct dl_phdr_info *a)