2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * Copyright 2009-2012 Konstantin Belousov <kib@FreeBSD.ORG>.
5 * Copyright 2012 John Marino <draco@marino.st>.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 * Dynamic linker for ELF.
34 * John Polstra <jdp@polstra.com>.
38 #error "GCC is needed to compile this file"
41 #include <sys/param.h>
42 #include <sys/mount.h>
45 #include <sys/sysctl.h>
47 #include <sys/utsname.h>
48 #include <sys/ktrace.h>
49 #include <sys/resident.h>
52 #include <machine/tls.h>
67 #include "rtld_printf.h"
70 #define PATH_RTLD "/usr/libexec/ld-elf.so.2"
71 #define LD_ARY_CACHE 16
74 typedef void (*func_ptr_type)();
75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
78 * Function declarations.
80 static const char *_getenv_ld(const char *id);
81 static void die(void) __dead2;
82 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
83 const Elf_Dyn **, const Elf_Dyn **);
84 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
86 static void digest_dynamic(Obj_Entry *, int);
87 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
88 static Obj_Entry *dlcheck(void *);
89 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
90 int lo_flags, int mode, RtldLockState *lockstate);
91 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
92 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
93 static bool donelist_check(DoneList *, const Obj_Entry *);
94 static void errmsg_restore(char *);
95 static char *errmsg_save(void);
96 static void *fill_search_info(const char *, size_t, void *);
97 static char *find_library(const char *, const Obj_Entry *);
98 static const char *gethints(bool);
99 static void init_dag(Obj_Entry *);
100 static void init_rtld(caddr_t, Elf_Auxinfo **);
101 static void initlist_add_neededs(Needed_Entry *, Objlist *);
102 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
103 static void linkmap_add(Obj_Entry *);
104 static void linkmap_delete(Obj_Entry *);
105 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
106 static void unload_filtees(Obj_Entry *);
107 static int load_needed_objects(Obj_Entry *, int);
108 static int load_preload_objects(void);
109 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
110 static void map_stacks_exec(RtldLockState *);
111 static Obj_Entry *obj_from_addr(const void *);
112 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
113 static void objlist_call_init(Objlist *, RtldLockState *);
114 static void objlist_clear(Objlist *);
115 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
116 static void objlist_init(Objlist *);
117 static void objlist_push_head(Objlist *, Obj_Entry *);
118 static void objlist_push_tail(Objlist *, Obj_Entry *);
119 static void objlist_remove(Objlist *, Obj_Entry *);
120 static void *path_enumerate(const char *, path_enum_proc, void *);
121 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
122 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
123 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
124 int flags, RtldLockState *lockstate);
125 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
127 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
128 int flags, RtldLockState *lockstate);
129 static int rtld_dirname(const char *, char *);
130 static int rtld_dirname_abs(const char *, char *);
131 static void *rtld_dlopen(const char *name, int fd, int mode);
132 static void rtld_exit(void);
133 static char *search_library_path(const char *, const char *);
134 static const void **get_program_var_addr(const char *, RtldLockState *);
135 static void set_program_var(const char *, const void *);
136 static int symlook_default(SymLook *, const Obj_Entry *refobj);
137 static int symlook_global(SymLook *, DoneList *);
138 static void symlook_init_from_req(SymLook *, const SymLook *);
139 static int symlook_list(SymLook *, const Objlist *, DoneList *);
140 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
141 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
142 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
143 static void trace_loaded_objects(Obj_Entry *);
144 static void unlink_object(Obj_Entry *);
145 static void unload_object(Obj_Entry *);
146 static void unref_dag(Obj_Entry *);
147 static void ref_dag(Obj_Entry *);
148 static char *origin_subst_one(char *, const char *, const char *, bool);
149 static char *origin_subst(char *, const char *);
150 static void preinit_main(void);
151 static int rtld_verify_versions(const Objlist *);
152 static int rtld_verify_object_versions(Obj_Entry *);
153 static void object_add_name(Obj_Entry *, const char *);
154 static int object_match_name(const Obj_Entry *, const char *);
155 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
156 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
157 struct dl_phdr_info *phdr_info);
158 static uint_fast32_t gnu_hash (const char *);
159 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
160 const unsigned long);
162 void r_debug_state(struct r_debug *, struct link_map *) __noinline;
167 static char *error_message; /* Message for dlerror(), or NULL */
168 struct r_debug r_debug; /* for GDB; */
169 static bool libmap_disable; /* Disable libmap */
170 static bool ld_loadfltr; /* Immediate filters processing */
171 static char *libmap_override; /* Maps to use in addition to libmap.conf */
172 static bool trust; /* False for setuid and setgid programs */
173 static bool dangerous_ld_env; /* True if environment variables have been
174 used to affect the libraries loaded */
175 static const char *ld_bind_now; /* Environment variable for immediate binding */
176 static const char *ld_debug; /* Environment variable for debugging */
177 static const char *ld_library_path; /* Environment variable for search path */
178 static char *ld_preload; /* Environment variable for libraries to
180 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */
181 static const char *ld_tracing; /* Called from ldd to print libs */
182 static const char *ld_utrace; /* Use utrace() to log events. */
183 static int (*rtld_functrace)( /* Optional function call tracing hook */
184 const char *caller_obj,
185 const char *callee_obj,
186 const char *callee_func,
188 static const Obj_Entry *rtld_functrace_obj; /* Object thereof */
189 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
190 static Obj_Entry **obj_tail; /* Link field of last object in list */
191 static Obj_Entry **preload_tail;
192 static Obj_Entry *obj_main; /* The main program shared object */
193 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
194 static unsigned int obj_count; /* Number of objects in obj_list */
195 static unsigned int obj_loads; /* Number of objects in obj_list */
197 static int ld_resident; /* Non-zero if resident */
198 static const char *ld_ary[LD_ARY_CACHE];
200 static Objlist initlist;
202 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
203 STAILQ_HEAD_INITIALIZER(list_global);
204 static Objlist list_main = /* Objects loaded at program startup */
205 STAILQ_HEAD_INITIALIZER(list_main);
206 static Objlist list_fini = /* Objects needing fini() calls */
207 STAILQ_HEAD_INITIALIZER(list_fini);
209 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */
211 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
213 extern Elf_Dyn _DYNAMIC;
214 #pragma weak _DYNAMIC
215 #ifndef RTLD_IS_DYNAMIC
216 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
219 #ifdef ENABLE_OSRELDATE
223 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
224 static int max_stack_flags;
227 * Global declarations normally provided by crt1. The dynamic linker is
228 * not built with crt1, so we have to provide them ourselves.
234 * Used to pass argc, argv to init functions.
240 * Globals to control TLS allocation.
242 size_t tls_last_offset; /* Static TLS offset of last module */
243 size_t tls_last_size; /* Static TLS size of last module */
244 size_t tls_static_space; /* Static TLS space allocated */
245 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
246 int tls_max_index = 1; /* Largest module index allocated */
249 * Fill in a DoneList with an allocation large enough to hold all of
250 * the currently-loaded objects. Keep this as a macro since it calls
251 * alloca and we want that to occur within the scope of the caller.
253 #define donelist_init(dlp) \
254 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
255 assert((dlp)->objs != NULL), \
256 (dlp)->num_alloc = obj_count, \
259 #define UTRACE_DLOPEN_START 1
260 #define UTRACE_DLOPEN_STOP 2
261 #define UTRACE_DLCLOSE_START 3
262 #define UTRACE_DLCLOSE_STOP 4
263 #define UTRACE_LOAD_OBJECT 5
264 #define UTRACE_UNLOAD_OBJECT 6
265 #define UTRACE_ADD_RUNDEP 7
266 #define UTRACE_PRELOAD_FINISHED 8
267 #define UTRACE_INIT_CALL 9
268 #define UTRACE_FINI_CALL 10
271 char sig[4]; /* 'RTLD' */
274 void *mapbase; /* Used for 'parent' and 'init/fini' */
276 int refcnt; /* Used for 'mode' */
277 char name[MAXPATHLEN];
280 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
281 if (ld_utrace != NULL) \
282 ld_utrace_log(e, h, mb, ms, r, n); \
286 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
287 int refcnt, const char *name)
289 struct utrace_rtld ut;
297 ut.mapbase = mapbase;
298 ut.mapsize = mapsize;
300 bzero(ut.name, sizeof(ut.name));
302 strlcpy(ut.name, name, sizeof(ut.name));
303 utrace(&ut, sizeof(ut));
307 * Main entry point for dynamic linking. The first argument is the
308 * stack pointer. The stack is expected to be laid out as described
309 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
310 * Specifically, the stack pointer points to a word containing
311 * ARGC. Following that in the stack is a null-terminated sequence
312 * of pointers to argument strings. Then comes a null-terminated
313 * sequence of pointers to environment strings. Finally, there is a
314 * sequence of "auxiliary vector" entries.
316 * The second argument points to a place to store the dynamic linker's
317 * exit procedure pointer and the third to a place to store the main
320 * The return value is the main program's entry point.
323 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
325 Elf_Auxinfo *aux_info[AT_COUNT];
333 Objlist_Entry *entry;
336 /* marino: DO NOT MOVE THESE VARIABLES TO _rtld
337 Obj_Entry **preload_tail;
339 from global to here. It will break the DWARF2 unwind scheme.
340 The system compilers were unaffected, but not gcc 4.6
344 * On entry, the dynamic linker itself has not been relocated yet.
345 * Be very careful not to reference any global data until after
346 * init_rtld has returned. It is OK to reference file-scope statics
347 * and string constants, and to call static and global functions.
350 /* Find the auxiliary vector on the stack. */
353 sp += argc + 1; /* Skip over arguments and NULL terminator */
357 * If we aren't already resident we have to dig out some more info.
358 * Note that auxinfo does not exist when we are resident.
360 * I'm not sure about the ld_resident check. It seems to read zero
361 * prior to relocation, which is what we want. When running from a
362 * resident copy everything will be relocated so we are definitely
365 if (ld_resident == 0) {
366 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
368 aux = (Elf_Auxinfo *) sp;
370 /* Digest the auxiliary vector. */
371 for (i = 0; i < AT_COUNT; i++)
373 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
374 if (auxp->a_type < AT_COUNT)
375 aux_info[auxp->a_type] = auxp;
378 /* Initialize and relocate ourselves. */
379 assert(aux_info[AT_BASE] != NULL);
380 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
383 ld_index = 0; /* don't use old env cache in case we are resident */
384 __progname = obj_rtld.path;
385 argv0 = argv[0] != NULL ? argv[0] : "(null)";
390 trust = !issetugid();
392 ld_bind_now = _getenv_ld("LD_BIND_NOW");
394 * If the process is tainted, then we un-set the dangerous environment
395 * variables. The process will be marked as tainted until setuid(2)
396 * is called. If any child process calls setuid(2) we do not want any
397 * future processes to honor the potentially un-safe variables.
400 if ( unsetenv("LD_DEBUG")
401 || unsetenv("LD_PRELOAD")
402 || unsetenv("LD_LIBRARY_PATH")
403 || unsetenv("LD_ELF_HINTS_PATH")
404 || unsetenv("LD_LIBMAP")
405 || unsetenv("LD_LIBMAP_DISABLE")
406 || unsetenv("LD_LOADFLTR")
408 _rtld_error("environment corrupt; aborting");
412 ld_debug = _getenv_ld("LD_DEBUG");
413 libmap_disable = _getenv_ld("LD_LIBMAP_DISABLE") != NULL;
414 libmap_override = (char *)_getenv_ld("LD_LIBMAP");
415 ld_library_path = _getenv_ld("LD_LIBRARY_PATH");
416 ld_preload = (char *)_getenv_ld("LD_PRELOAD");
417 ld_elf_hints_path = _getenv_ld("LD_ELF_HINTS_PATH");
418 ld_loadfltr = _getenv_ld("LD_LOADFLTR") != NULL;
419 dangerous_ld_env = (ld_library_path != NULL)
420 || (ld_preload != NULL)
421 || (ld_elf_hints_path != NULL)
423 || (libmap_override != NULL)
426 ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS");
427 ld_utrace = _getenv_ld("LD_UTRACE");
429 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
430 ld_elf_hints_path = _PATH_ELF_HINTS;
432 if (ld_debug != NULL && *ld_debug != '\0')
434 dbg("%s is initialized, base address = %p", __progname,
435 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
436 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
437 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
439 dbg("initializing thread locks");
443 * If we are resident we can skip work that we have already done.
444 * Note that the stack is reset and there is no Elf_Auxinfo
445 * when running from a resident image, and the static globals setup
446 * between here and resident_skip will have already been setup.
452 * Load the main program, or process its program header if it is
455 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
456 int fd = aux_info[AT_EXECFD]->a_un.a_val;
457 dbg("loading main program");
458 obj_main = map_object(fd, argv0, NULL);
460 if (obj_main == NULL)
462 max_stack_flags = obj->stack_flags;
463 } else { /* Main program already loaded. */
464 const Elf_Phdr *phdr;
468 dbg("processing main program's program header");
469 assert(aux_info[AT_PHDR] != NULL);
470 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
471 assert(aux_info[AT_PHNUM] != NULL);
472 phnum = aux_info[AT_PHNUM]->a_un.a_val;
473 assert(aux_info[AT_PHENT] != NULL);
474 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
475 assert(aux_info[AT_ENTRY] != NULL);
476 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
477 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
481 char buf[MAXPATHLEN];
482 if (aux_info[AT_EXECPATH] != NULL) {
485 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
486 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
487 if (kexecpath[0] == '/')
488 obj_main->path = kexecpath;
489 else if (getcwd(buf, sizeof(buf)) == NULL ||
490 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
491 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
492 obj_main->path = xstrdup(argv0);
494 obj_main->path = xstrdup(buf);
496 char resolved[MAXPATHLEN];
497 dbg("No AT_EXECPATH");
498 if (argv0[0] == '/') {
499 if (realpath(argv0, resolved) != NULL)
500 obj_main->path = xstrdup(resolved);
502 obj_main->path = xstrdup(argv0);
504 if (getcwd(buf, sizeof(buf)) != NULL
505 && strlcat(buf, "/", sizeof(buf)) < sizeof(buf)
506 && strlcat(buf, argv0, sizeof (buf)) < sizeof(buf)
507 && access(buf, R_OK) == 0
508 && realpath(buf, resolved) != NULL)
509 obj_main->path = xstrdup(resolved);
511 obj_main->path = xstrdup(argv0);
514 dbg("obj_main path %s", obj_main->path);
515 obj_main->mainprog = true;
517 if (aux_info[AT_STACKPROT] != NULL &&
518 aux_info[AT_STACKPROT]->a_un.a_val != 0)
519 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
522 * Get the actual dynamic linker pathname from the executable if
523 * possible. (It should always be possible.) That ensures that
524 * gdb will find the right dynamic linker even if a non-standard
527 if (obj_main->interp != NULL &&
528 strcmp(obj_main->interp, obj_rtld.path) != 0) {
530 obj_rtld.path = xstrdup(obj_main->interp);
531 __progname = obj_rtld.path;
534 digest_dynamic(obj_main, 0);
535 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
536 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
537 obj_main->dynsymcount);
539 linkmap_add(obj_main);
540 linkmap_add(&obj_rtld);
542 /* Link the main program into the list of objects. */
543 *obj_tail = obj_main;
544 obj_tail = &obj_main->next;
548 /* Initialize a fake symbol for resolving undefined weak references. */
549 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
550 sym_zero.st_shndx = SHN_UNDEF;
551 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
554 libmap_disable = (bool)lm_init(libmap_override);
556 dbg("loading LD_PRELOAD libraries");
557 if (load_preload_objects() == -1)
559 preload_tail = obj_tail;
561 dbg("loading needed objects");
562 if (load_needed_objects(obj_main, 0) == -1)
565 /* Make a list of all objects loaded at startup. */
566 for (obj = obj_list; obj != NULL; obj = obj->next) {
567 objlist_push_tail(&list_main, obj);
571 dbg("checking for required versions");
572 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
577 if (ld_tracing) { /* We're done */
578 trace_loaded_objects(obj_main);
582 if (ld_resident) /* XXX clean this up! */
585 if (_getenv_ld("LD_DUMP_REL_PRE") != NULL) {
586 dump_relocations(obj_main);
590 /* setup TLS for main thread */
591 dbg("initializing initial thread local storage");
592 STAILQ_FOREACH(entry, &list_main, link) {
594 * Allocate all the initial objects out of the static TLS
595 * block even if they didn't ask for it.
597 allocate_tls_offset(entry->obj);
600 tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA;
603 * Do not try to allocate the TLS here, let libc do it itself.
604 * (crt1 for the program will call _init_tls())
607 if (relocate_objects(obj_main,
608 ld_bind_now != NULL && *ld_bind_now != '\0',
609 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
612 dbg("doing copy relocations");
613 if (do_copy_relocations(obj_main) == -1)
618 if (_getenv_ld("LD_RESIDENT_UNREGISTER_NOW")) {
619 if (exec_sys_unregister(-1) < 0) {
620 dbg("exec_sys_unregister failed %d\n", errno);
623 dbg("exec_sys_unregister success\n");
627 if (_getenv_ld("LD_DUMP_REL_POST") != NULL) {
628 dump_relocations(obj_main);
632 dbg("initializing key program variables");
633 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
634 set_program_var("environ", env);
635 set_program_var("__elf_aux_vector", aux);
637 if (_getenv_ld("LD_RESIDENT_REGISTER_NOW")) {
638 extern void resident_start(void);
640 if (exec_sys_register(resident_start) < 0) {
641 dbg("exec_sys_register failed %d\n", errno);
644 dbg("exec_sys_register success\n");
648 /* Make a list of init functions to call. */
649 objlist_init(&initlist);
650 initlist_add_objects(obj_list, preload_tail, &initlist);
652 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
654 map_stacks_exec(NULL);
656 dbg("resolving ifuncs");
657 if (resolve_objects_ifunc(obj_main,
658 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
663 * Do NOT call the initlist here, give libc a chance to set up
664 * the initial TLS segment. crt1 will then call _rtld_call_init().
667 dbg("transferring control to program entry point = %p", obj_main->entry);
669 /* Return the exit procedure and the program entry point. */
670 *exit_proc = rtld_exit;
672 return (func_ptr_type) obj_main->entry;
676 * Call the initialization list for dynamically loaded libraries.
677 * (called from crt1.c).
680 _rtld_call_init(void)
682 RtldLockState lockstate;
685 if (!obj_main->note_present && obj_main->valid_hash_gnu) {
687 * The use of a linker script with a PHDRS directive that does not include
688 * PT_NOTE will block the crt_no_init note. In this case we'll look for the
689 * recently added GNU hash dynamic tag which gets built by default. It is
690 * extremely unlikely to find a pre-3.1 binary without a PT_NOTE header and
691 * a gnu hash tag. If gnu hash found, consider binary to use new crt code.
693 obj_main->crt_no_init = true;
694 dbg("Setting crt_no_init without presence of PT_NOTE header");
697 wlock_acquire(rtld_bind_lock, &lockstate);
698 if (obj_main->crt_no_init)
702 * Make sure we don't call the main program's init and fini functions
703 * for binaries linked with old crt1 which calls _init itself.
705 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
706 obj_main->init_array = obj_main->fini_array = (Elf_Addr)NULL;
708 objlist_call_init(&initlist, &lockstate);
709 objlist_clear(&initlist);
710 dbg("loading filtees");
711 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
712 if (ld_loadfltr || obj->z_loadfltr)
713 load_filtees(obj, 0, &lockstate);
715 lock_release(rtld_bind_lock, &lockstate);
719 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
724 ptr = (void *)make_function_pointer(def, obj);
725 target = ((Elf_Addr (*)(void))ptr)();
726 return ((void *)target);
730 _rtld_bind(Obj_Entry *obj, Elf_Size reloff, void *stack)
734 const Obj_Entry *defobj;
737 RtldLockState lockstate;
739 rlock_acquire(rtld_bind_lock, &lockstate);
740 if (sigsetjmp(lockstate.env, 0) != 0)
741 lock_upgrade(rtld_bind_lock, &lockstate);
743 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
745 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
747 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
748 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
752 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
753 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
755 target = (Elf_Addr)(defobj->relocbase + def->st_value);
757 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
758 defobj->strtab + def->st_name, basename(obj->path),
759 (void *)target, basename(defobj->path));
762 * If we have a function call tracing hook, and the
763 * hook would like to keep tracing this one function,
764 * prevent the relocation so we will wind up here
765 * the next time again.
767 * We don't want to functrace calls from the functracer
768 * to avoid recursive loops.
770 if (rtld_functrace != NULL && obj != rtld_functrace_obj) {
771 if (rtld_functrace(obj->path,
773 defobj->strtab + def->st_name,
775 lock_release(rtld_bind_lock, &lockstate);
781 * Write the new contents for the jmpslot. Note that depending on
782 * architecture, the value which we need to return back to the
783 * lazy binding trampoline may or may not be the target
784 * address. The value returned from reloc_jmpslot() is the value
785 * that the trampoline needs.
787 target = reloc_jmpslot(where, target, defobj, obj, rel);
788 lock_release(rtld_bind_lock, &lockstate);
793 * Error reporting function. Use it like printf. If formats the message
794 * into a buffer, and sets things up so that the next call to dlerror()
795 * will return the message.
798 _rtld_error(const char *fmt, ...)
800 static char buf[512];
804 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
810 * Return a dynamically-allocated copy of the current error message, if any.
815 return error_message == NULL ? NULL : xstrdup(error_message);
819 * Restore the current error message from a copy which was previously saved
820 * by errmsg_save(). The copy is freed.
823 errmsg_restore(char *saved_msg)
825 if (saved_msg == NULL)
826 error_message = NULL;
828 _rtld_error("%s", saved_msg);
834 basename(const char *name)
836 const char *p = strrchr(name, '/');
837 return p != NULL ? p + 1 : name;
840 static struct utsname uts;
843 origin_subst_one(char *real, const char *kw, const char *subst,
846 char *p, *p1, *res, *resp;
847 int subst_len, kw_len, subst_count, old_len, new_len;
852 * First, count the number of the keyword occurences, to
853 * preallocate the final string.
855 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
862 * If the keyword is not found, just return.
864 if (subst_count == 0)
865 return (may_free ? real : xstrdup(real));
868 * There is indeed something to substitute. Calculate the
869 * length of the resulting string, and allocate it.
871 subst_len = strlen(subst);
872 old_len = strlen(real);
873 new_len = old_len + (subst_len - kw_len) * subst_count;
874 res = xmalloc(new_len + 1);
877 * Now, execute the substitution loop.
879 for (p = real, resp = res, *resp = '\0';;) {
882 /* Copy the prefix before keyword. */
883 memcpy(resp, p, p1 - p);
885 /* Keyword replacement. */
886 memcpy(resp, subst, subst_len);
894 /* Copy to the end of string and finish. */
902 origin_subst(char *real, const char *origin_path)
904 char *res1, *res2, *res3, *res4;
906 if (uts.sysname[0] == '\0') {
907 if (uname(&uts) != 0) {
908 _rtld_error("utsname failed: %d", errno);
912 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false);
913 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true);
914 res3 = origin_subst_one(res2, "$OSREL", uts.release, true);
915 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true);
922 const char *msg = dlerror();
926 rtld_fdputstr(STDERR_FILENO, msg);
927 rtld_fdputchar(STDERR_FILENO, '\n');
932 * Process a shared object's DYNAMIC section, and save the important
933 * information in its Obj_Entry structure.
936 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
937 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
940 Needed_Entry **needed_tail = &obj->needed;
941 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
942 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
943 const Elf_Hashelt *hashtab;
944 const Elf32_Word *hashval;
945 Elf32_Word bkt, nmaskwords;
948 int plttype = DT_REL;
954 obj->bind_now = false;
955 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
956 switch (dynp->d_tag) {
959 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
963 obj->relsize = dynp->d_un.d_val;
967 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
971 obj->pltrel = (const Elf_Rel *)
972 (obj->relocbase + dynp->d_un.d_ptr);
976 obj->pltrelsize = dynp->d_un.d_val;
980 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
984 obj->relasize = dynp->d_un.d_val;
988 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
992 plttype = dynp->d_un.d_val;
993 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
997 obj->symtab = (const Elf_Sym *)
998 (obj->relocbase + dynp->d_un.d_ptr);
1002 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1006 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
1010 obj->strsize = dynp->d_un.d_val;
1014 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
1019 obj->verneednum = dynp->d_un.d_val;
1023 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
1028 obj->verdefnum = dynp->d_un.d_val;
1032 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1038 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1040 obj->nbuckets = hashtab[0];
1041 obj->nchains = hashtab[1];
1042 obj->buckets = hashtab + 2;
1043 obj->chains = obj->buckets + obj->nbuckets;
1044 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1045 obj->buckets != NULL;
1051 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1053 obj->nbuckets_gnu = hashtab[0];
1054 obj->symndx_gnu = hashtab[1];
1055 nmaskwords = hashtab[2];
1056 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1057 /* Number of bitmask words is required to be power of 2 */
1058 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0);
1059 obj->maskwords_bm_gnu = nmaskwords - 1;
1060 obj->shift2_gnu = hashtab[3];
1061 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
1062 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1063 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1065 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 &&
1066 obj->buckets_gnu != NULL;
1072 Needed_Entry *nep = NEW(Needed_Entry);
1073 nep->name = dynp->d_un.d_val;
1078 needed_tail = &nep->next;
1084 Needed_Entry *nep = NEW(Needed_Entry);
1085 nep->name = dynp->d_un.d_val;
1089 *needed_filtees_tail = nep;
1090 needed_filtees_tail = &nep->next;
1096 Needed_Entry *nep = NEW(Needed_Entry);
1097 nep->name = dynp->d_un.d_val;
1101 *needed_aux_filtees_tail = nep;
1102 needed_aux_filtees_tail = &nep->next;
1107 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1111 obj->textrel = true;
1115 obj->symbolic = true;
1120 * We have to wait until later to process this, because we
1121 * might not have gotten the address of the string table yet.
1131 *dyn_runpath = dynp;
1135 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1139 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1142 case DT_PREINIT_ARRAY:
1143 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1147 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1151 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1154 case DT_PREINIT_ARRAYSZ:
1155 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1158 case DT_INIT_ARRAYSZ:
1159 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1162 case DT_FINI_ARRAYSZ:
1163 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1167 /* XXX - not implemented yet */
1169 dbg("Filling in DT_DEBUG entry");
1170 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1174 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1175 obj->z_origin = true;
1176 if (dynp->d_un.d_val & DF_SYMBOLIC)
1177 obj->symbolic = true;
1178 if (dynp->d_un.d_val & DF_TEXTREL)
1179 obj->textrel = true;
1180 if (dynp->d_un.d_val & DF_BIND_NOW)
1181 obj->bind_now = true;
1182 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1187 if (dynp->d_un.d_val & DF_1_NOOPEN)
1188 obj->z_noopen = true;
1189 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1190 obj->z_origin = true;
1191 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1193 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1194 obj->bind_now = true;
1195 if (dynp->d_un.d_val & DF_1_NODELETE)
1196 obj->z_nodelete = true;
1197 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1198 obj->z_loadfltr = true;
1199 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1200 obj->z_nodeflib = true;
1205 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1212 obj->traced = false;
1214 if (plttype == DT_RELA) {
1215 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1217 obj->pltrelasize = obj->pltrelsize;
1218 obj->pltrelsize = 0;
1221 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1222 if (obj->valid_hash_sysv)
1223 obj->dynsymcount = obj->nchains;
1224 else if (obj->valid_hash_gnu) {
1225 obj->dynsymcount = 0;
1226 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1227 if (obj->buckets_gnu[bkt] == 0)
1229 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1232 while ((*hashval++ & 1u) == 0);
1234 obj->dynsymcount += obj->symndx_gnu;
1239 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1240 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1243 if (obj->z_origin && obj->origin_path == NULL) {
1244 obj->origin_path = xmalloc(PATH_MAX);
1245 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1249 if (dyn_runpath != NULL) {
1250 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1252 obj->runpath = origin_subst(obj->runpath, obj->origin_path);
1254 else if (dyn_rpath != NULL) {
1255 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1257 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1260 if (dyn_soname != NULL)
1261 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1265 digest_dynamic(Obj_Entry *obj, int early)
1267 const Elf_Dyn *dyn_rpath;
1268 const Elf_Dyn *dyn_soname;
1269 const Elf_Dyn *dyn_runpath;
1271 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1272 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1276 * Process a shared object's program header. This is used only for the
1277 * main program, when the kernel has already loaded the main program
1278 * into memory before calling the dynamic linker. It creates and
1279 * returns an Obj_Entry structure.
1282 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1285 const Elf_Phdr *phlimit = phdr + phnum;
1287 Elf_Addr note_start, note_end;
1291 for (ph = phdr; ph < phlimit; ph++) {
1292 if (ph->p_type != PT_PHDR)
1296 obj->phsize = ph->p_memsz;
1297 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1301 obj->stack_flags = PF_X | PF_R | PF_W;
1303 for (ph = phdr; ph < phlimit; ph++) {
1304 switch (ph->p_type) {
1307 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1311 if (nsegs == 0) { /* First load segment */
1312 obj->vaddrbase = trunc_page(ph->p_vaddr);
1313 obj->mapbase = obj->vaddrbase + obj->relocbase;
1314 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1316 } else { /* Last load segment */
1317 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1324 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1329 obj->tlssize = ph->p_memsz;
1330 obj->tlsalign = ph->p_align;
1331 obj->tlsinitsize = ph->p_filesz;
1332 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1336 obj->stack_flags = ph->p_flags;
1340 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1341 obj->relro_size = round_page(ph->p_memsz);
1345 obj->note_present = true;
1346 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1347 note_end = note_start + ph->p_filesz;
1348 digest_notes(obj, note_start, note_end);
1353 _rtld_error("%s: too few PT_LOAD segments", path);
1362 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1364 const Elf_Note *note;
1365 const char *note_name;
1368 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1369 note = (const Elf_Note *)((const char *)(note + 1) +
1370 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1371 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1372 if (note->n_namesz != sizeof(NOTE_VENDOR) ||
1373 note->n_descsz != sizeof(int32_t))
1375 if (note->n_type != ABI_NOTETYPE &&
1376 note->n_type != CRT_NOINIT_NOTETYPE)
1378 note_name = (const char *)(note + 1);
1379 if (strncmp(NOTE_VENDOR, note_name, sizeof(NOTE_VENDOR)) != 0)
1381 switch (note->n_type) {
1383 /* DragonFly osrel note */
1384 p = (uintptr_t)(note + 1);
1385 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1386 obj->osrel = *(const int32_t *)(p);
1387 dbg("note osrel %d", obj->osrel);
1389 case CRT_NOINIT_NOTETYPE:
1390 /* DragonFly 'crt does not call init' note */
1391 obj->crt_no_init = true;
1392 dbg("note crt_no_init");
1399 dlcheck(void *handle)
1403 for (obj = obj_list; obj != NULL; obj = obj->next)
1404 if (obj == (Obj_Entry *) handle)
1407 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1408 _rtld_error("Invalid shared object handle %p", handle);
1415 * If the given object is already in the donelist, return true. Otherwise
1416 * add the object to the list and return false.
1419 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1423 for (i = 0; i < dlp->num_used; i++)
1424 if (dlp->objs[i] == obj)
1427 * Our donelist allocation should always be sufficient. But if
1428 * our threads locking isn't working properly, more shared objects
1429 * could have been loaded since we allocated the list. That should
1430 * never happen, but we'll handle it properly just in case it does.
1432 if (dlp->num_used < dlp->num_alloc)
1433 dlp->objs[dlp->num_used++] = obj;
1438 * Hash function for symbol table lookup. Don't even think about changing
1439 * this. It is specified by the System V ABI.
1442 elf_hash(const char *name)
1444 const unsigned char *p = (const unsigned char *) name;
1445 unsigned long h = 0;
1448 while (*p != '\0') {
1449 h = (h << 4) + *p++;
1450 if ((g = h & 0xf0000000) != 0)
1458 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1459 * unsigned in case it's implemented with a wider type.
1461 static uint_fast32_t
1462 gnu_hash(const char *s)
1468 for (c = *s; c != '\0'; c = *++s)
1470 return (h & 0xffffffff);
1474 * Find the library with the given name, and return its full pathname.
1475 * The returned string is dynamically allocated. Generates an error
1476 * message and returns NULL if the library cannot be found.
1478 * If the second argument is non-NULL, then it refers to an already-
1479 * loaded shared object, whose library search path will be searched.
1481 * The search order is:
1482 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1483 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1485 * DT_RUNPATH in the referencing file
1486 * ldconfig hints (if -z nodefaultlib, filter out /usr/lib from list)
1487 * /usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1489 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1492 find_library(const char *xname, const Obj_Entry *refobj)
1496 bool nodeflib, objgiven;
1498 objgiven = refobj != NULL;
1499 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1500 if (xname[0] != '/' && !trust) {
1501 _rtld_error("Absolute pathname required for shared object \"%s\"",
1505 if (objgiven && refobj->z_origin) {
1506 return (origin_subst(__DECONST(char *, xname),
1507 refobj->origin_path));
1509 return (xstrdup(xname));
1513 if (libmap_disable || !objgiven ||
1514 (name = lm_find(refobj->path, xname)) == NULL)
1515 name = (char *)xname;
1517 dbg(" Searching for \"%s\"", name);
1519 nodeflib = objgiven ? refobj->z_nodeflib : false;
1521 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1522 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1523 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1524 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1526 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1527 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1528 (objgiven && !nodeflib &&
1529 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1532 if (objgiven && refobj->path != NULL) {
1533 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1534 name, basename(refobj->path));
1536 _rtld_error("Shared object \"%s\" not found", name);
1542 * Given a symbol number in a referencing object, find the corresponding
1543 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1544 * no definition was found. Returns a pointer to the Obj_Entry of the
1545 * defining object via the reference parameter DEFOBJ_OUT.
1548 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1549 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1550 RtldLockState *lockstate)
1554 const Obj_Entry *defobj;
1560 * If we have already found this symbol, get the information from
1563 if (symnum >= refobj->dynsymcount)
1564 return NULL; /* Bad object */
1565 if (cache != NULL && cache[symnum].sym != NULL) {
1566 *defobj_out = cache[symnum].obj;
1567 return cache[symnum].sym;
1570 ref = refobj->symtab + symnum;
1571 name = refobj->strtab + ref->st_name;
1576 * We don't have to do a full scale lookup if the symbol is local.
1577 * We know it will bind to the instance in this load module; to
1578 * which we already have a pointer (ie ref). By not doing a lookup,
1579 * we not only improve performance, but it also avoids unresolvable
1580 * symbols when local symbols are not in the hash table.
1582 * This might occur for TLS module relocations, which simply use
1585 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1586 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1587 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1590 symlook_init(&req, name);
1592 req.ventry = fetch_ventry(refobj, symnum);
1593 req.lockstate = lockstate;
1594 res = symlook_default(&req, refobj);
1597 defobj = req.defobj_out;
1605 * If we found no definition and the reference is weak, treat the
1606 * symbol as having the value zero.
1608 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1614 *defobj_out = defobj;
1615 /* Record the information in the cache to avoid subsequent lookups. */
1616 if (cache != NULL) {
1617 cache[symnum].sym = def;
1618 cache[symnum].obj = defobj;
1621 if (refobj != &obj_rtld)
1622 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1628 * Return the search path from the ldconfig hints file, reading it if
1629 * necessary. If nostdlib is true, then the default search paths are
1630 * not added to result.
1632 * Returns NULL if there are problems with the hints file,
1633 * or if the search path there is empty.
1636 gethints(bool nostdlib)
1638 static char *hints, *filtered_path;
1639 struct elfhints_hdr hdr;
1640 struct fill_search_info_args sargs, hargs;
1641 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1642 struct dl_serpath *SLPpath, *hintpath;
1644 unsigned int SLPndx, hintndx, fndx, fcount;
1649 /* First call, read the hints file */
1650 if (hints == NULL) {
1651 /* Keep from trying again in case the hints file is bad. */
1654 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1656 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1657 hdr.magic != ELFHINTS_MAGIC ||
1662 p = xmalloc(hdr.dirlistlen + 1);
1663 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1664 read(fd, p, hdr.dirlistlen + 1) !=
1665 (ssize_t)hdr.dirlistlen + 1) {
1675 * If caller agreed to receive list which includes the default
1676 * paths, we are done. Otherwise, if we still have not
1677 * calculated filtered result, do it now.
1680 return (hints[0] != '\0' ? hints : NULL);
1681 if (filtered_path != NULL)
1685 * Obtain the list of all configured search paths, and the
1686 * list of the default paths.
1688 * First estimate the size of the results.
1690 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1692 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1695 sargs.request = RTLD_DI_SERINFOSIZE;
1696 sargs.serinfo = &smeta;
1697 hargs.request = RTLD_DI_SERINFOSIZE;
1698 hargs.serinfo = &hmeta;
1700 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1701 path_enumerate(p, fill_search_info, &hargs);
1703 SLPinfo = xmalloc(smeta.dls_size);
1704 hintinfo = xmalloc(hmeta.dls_size);
1707 * Next fetch both sets of paths.
1709 sargs.request = RTLD_DI_SERINFO;
1710 sargs.serinfo = SLPinfo;
1711 sargs.serpath = &SLPinfo->dls_serpath[0];
1712 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1714 hargs.request = RTLD_DI_SERINFO;
1715 hargs.serinfo = hintinfo;
1716 hargs.serpath = &hintinfo->dls_serpath[0];
1717 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1719 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1720 path_enumerate(p, fill_search_info, &hargs);
1723 * Now calculate the difference between two sets, by excluding
1724 * standard paths from the full set.
1728 filtered_path = xmalloc(hdr.dirlistlen + 1);
1729 hintpath = &hintinfo->dls_serpath[0];
1730 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1732 SLPpath = &SLPinfo->dls_serpath[0];
1734 * Check each standard path against current.
1736 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1737 /* matched, skip the path */
1738 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1746 * Not matched against any standard path, add the path
1747 * to result. Separate consecutive paths with ':'.
1750 filtered_path[fndx] = ':';
1754 flen = strlen(hintpath->dls_name);
1755 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1758 filtered_path[fndx] = '\0';
1764 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1768 init_dag(Obj_Entry *root)
1770 const Needed_Entry *needed;
1771 const Objlist_Entry *elm;
1774 if (root->dag_inited)
1776 donelist_init(&donelist);
1778 /* Root object belongs to own DAG. */
1779 objlist_push_tail(&root->dldags, root);
1780 objlist_push_tail(&root->dagmembers, root);
1781 donelist_check(&donelist, root);
1784 * Add dependencies of root object to DAG in breadth order
1785 * by exploiting the fact that each new object get added
1786 * to the tail of the dagmembers list.
1788 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1789 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1790 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1792 objlist_push_tail(&needed->obj->dldags, root);
1793 objlist_push_tail(&root->dagmembers, needed->obj);
1796 root->dag_inited = true;
1800 process_nodelete(Obj_Entry *root)
1802 const Objlist_Entry *elm;
1805 * Walk over object DAG and process every dependent object that
1806 * is marked as DF_1_NODELETE. They need to grow their own DAG,
1807 * which then should have its reference upped separately.
1809 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1810 if (elm->obj != NULL && elm->obj->z_nodelete &&
1811 !elm->obj->ref_nodel) {
1812 dbg("obj %s nodelete", elm->obj->path);
1815 elm->obj->ref_nodel = true;
1821 * Initialize the dynamic linker. The argument is the address at which
1822 * the dynamic linker has been mapped into memory. The primary task of
1823 * this function is to relocate the dynamic linker.
1826 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1828 Obj_Entry objtmp; /* Temporary rtld object */
1829 const Elf_Dyn *dyn_rpath;
1830 const Elf_Dyn *dyn_soname;
1831 const Elf_Dyn *dyn_runpath;
1834 * Conjure up an Obj_Entry structure for the dynamic linker.
1836 * The "path" member can't be initialized yet because string constants
1837 * cannot yet be accessed. Below we will set it correctly.
1839 memset(&objtmp, 0, sizeof(objtmp));
1842 objtmp.mapbase = mapbase;
1844 objtmp.relocbase = mapbase;
1846 if (RTLD_IS_DYNAMIC()) {
1847 objtmp.dynamic = rtld_dynamic(&objtmp);
1848 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1849 assert(objtmp.needed == NULL);
1850 assert(!objtmp.textrel);
1853 * Temporarily put the dynamic linker entry into the object list, so
1854 * that symbols can be found.
1857 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1860 /* Initialize the object list. */
1861 obj_tail = &obj_list;
1863 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1864 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1866 #ifdef ENABLE_OSRELDATE
1867 if (aux_info[AT_OSRELDATE] != NULL)
1868 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1871 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1873 /* Replace the path with a dynamically allocated copy. */
1874 obj_rtld.path = xstrdup(PATH_RTLD);
1876 r_debug.r_brk = r_debug_state;
1877 r_debug.r_state = RT_CONSISTENT;
1881 * Add the init functions from a needed object list (and its recursive
1882 * needed objects) to "list". This is not used directly; it is a helper
1883 * function for initlist_add_objects(). The write lock must be held
1884 * when this function is called.
1887 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1889 /* Recursively process the successor needed objects. */
1890 if (needed->next != NULL)
1891 initlist_add_neededs(needed->next, list);
1893 /* Process the current needed object. */
1894 if (needed->obj != NULL)
1895 initlist_add_objects(needed->obj, &needed->obj->next, list);
1899 * Scan all of the DAGs rooted in the range of objects from "obj" to
1900 * "tail" and add their init functions to "list". This recurses over
1901 * the DAGs and ensure the proper init ordering such that each object's
1902 * needed libraries are initialized before the object itself. At the
1903 * same time, this function adds the objects to the global finalization
1904 * list "list_fini" in the opposite order. The write lock must be
1905 * held when this function is called.
1908 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1911 if (obj->init_scanned || obj->init_done)
1913 obj->init_scanned = true;
1915 /* Recursively process the successor objects. */
1916 if (&obj->next != tail)
1917 initlist_add_objects(obj->next, tail, list);
1919 /* Recursively process the needed objects. */
1920 if (obj->needed != NULL)
1921 initlist_add_neededs(obj->needed, list);
1922 if (obj->needed_filtees != NULL)
1923 initlist_add_neededs(obj->needed_filtees, list);
1924 if (obj->needed_aux_filtees != NULL)
1925 initlist_add_neededs(obj->needed_aux_filtees, list);
1927 /* Add the object to the init list. */
1928 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1929 obj->init_array != (Elf_Addr)NULL)
1930 objlist_push_tail(list, obj);
1932 /* Add the object to the global fini list in the reverse order. */
1933 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1934 && !obj->on_fini_list) {
1935 objlist_push_head(&list_fini, obj);
1936 obj->on_fini_list = true;
1941 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1945 free_needed_filtees(Needed_Entry *n)
1947 Needed_Entry *needed, *needed1;
1949 for (needed = n; needed != NULL; needed = needed->next) {
1950 if (needed->obj != NULL) {
1951 dlclose(needed->obj);
1955 for (needed = n; needed != NULL; needed = needed1) {
1956 needed1 = needed->next;
1962 unload_filtees(Obj_Entry *obj)
1965 free_needed_filtees(obj->needed_filtees);
1966 obj->needed_filtees = NULL;
1967 free_needed_filtees(obj->needed_aux_filtees);
1968 obj->needed_aux_filtees = NULL;
1969 obj->filtees_loaded = false;
1973 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
1974 RtldLockState *lockstate)
1977 for (; needed != NULL; needed = needed->next) {
1978 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
1979 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
1980 RTLD_LOCAL, lockstate);
1985 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
1988 lock_restart_for_upgrade(lockstate);
1989 if (!obj->filtees_loaded) {
1990 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
1991 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
1992 obj->filtees_loaded = true;
1997 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2001 for (; needed != NULL; needed = needed->next) {
2002 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2003 flags & ~RTLD_LO_NOLOAD);
2004 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2011 * Given a shared object, traverse its list of needed objects, and load
2012 * each of them. Returns 0 on success. Generates an error message and
2013 * returns -1 on failure.
2016 load_needed_objects(Obj_Entry *first, int flags)
2020 for (obj = first; obj != NULL; obj = obj->next) {
2021 if (process_needed(obj, obj->needed, flags) == -1)
2028 load_preload_objects(void)
2030 char *p = ld_preload;
2031 static const char delim[] = " \t:;";
2036 p += strspn(p, delim);
2037 while (*p != '\0') {
2038 size_t len = strcspn(p, delim);
2046 obj = load_object(p, -1, NULL, 0);
2048 return -1; /* XXX - cleanup */
2051 p += strspn(p, delim);
2053 /* Check for the magic tracing function */
2054 symlook_init(&req, RTLD_FUNCTRACE);
2055 res = symlook_obj(&req, obj);
2057 rtld_functrace = (void *)(req.defobj_out->relocbase +
2058 req.sym_out->st_value);
2059 rtld_functrace_obj = req.defobj_out;
2062 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2067 printable_path(const char *path)
2070 return (path == NULL ? "<unknown>" : path);
2074 * Load a shared object into memory, if it is not already loaded. The
2075 * object may be specified by name or by user-supplied file descriptor
2076 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2079 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2083 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2091 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2092 if (object_match_name(obj, name))
2096 path = find_library(name, refobj);
2103 * If we didn't find a match by pathname, or the name is not
2104 * supplied, open the file and check again by device and inode.
2105 * This avoids false mismatches caused by multiple links or ".."
2108 * To avoid a race, we open the file and use fstat() rather than
2113 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) {
2114 _rtld_error("Cannot open \"%s\"", path);
2119 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2122 * Temporary, remove at 3.6 branch
2123 * User might not have latest kernel installed
2124 * so fall back to old command for a while
2127 if (fd == -1 || (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)) {
2128 _rtld_error("Cannot dup fd");
2134 if (fstat(fd, &sb) == -1) {
2135 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2140 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2141 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2143 if (obj != NULL && name != NULL) {
2144 object_add_name(obj, name);
2149 if (flags & RTLD_LO_NOLOAD) {
2155 /* First use of this object, so we must map it in */
2156 obj = do_load_object(fd, name, path, &sb, flags);
2165 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2172 * but first, make sure that environment variables haven't been
2173 * used to circumvent the noexec flag on a filesystem.
2175 if (dangerous_ld_env) {
2176 if (fstatfs(fd, &fs) != 0) {
2177 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2180 if (fs.f_flags & MNT_NOEXEC) {
2181 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2185 dbg("loading \"%s\"", printable_path(path));
2186 obj = map_object(fd, printable_path(path), sbp);
2191 * If DT_SONAME is present in the object, digest_dynamic2 already
2192 * added it to the object names.
2195 object_add_name(obj, name);
2197 digest_dynamic(obj, 0);
2198 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2199 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2200 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2202 dbg("refusing to load non-loadable \"%s\"", obj->path);
2203 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2204 munmap(obj->mapbase, obj->mapsize);
2210 obj_tail = &obj->next;
2213 linkmap_add(obj); /* for GDB & dlinfo() */
2214 max_stack_flags |= obj->stack_flags;
2216 dbg(" %p .. %p: %s", obj->mapbase,
2217 obj->mapbase + obj->mapsize - 1, obj->path);
2219 dbg(" WARNING: %s has impure text", obj->path);
2220 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2227 obj_from_addr(const void *addr)
2231 for (obj = obj_list; obj != NULL; obj = obj->next) {
2232 if (addr < (void *) obj->mapbase)
2234 if (addr < (void *) (obj->mapbase + obj->mapsize))
2241 * If the main program is defined with a .preinit_array section, call
2242 * each function in order. This must occur before the initialization
2243 * of any shared object or the main program.
2248 Elf_Addr *preinit_addr;
2251 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2252 if (preinit_addr == NULL)
2255 for (index = 0; index < obj_main->preinit_array_num; index++) {
2256 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2257 dbg("calling preinit function for %s at %p", obj_main->path,
2258 (void *)preinit_addr[index]);
2259 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2260 0, 0, obj_main->path);
2261 call_init_pointer(obj_main, preinit_addr[index]);
2267 * Call the finalization functions for each of the objects in "list"
2268 * belonging to the DAG of "root" and referenced once. If NULL "root"
2269 * is specified, every finalization function will be called regardless
2270 * of the reference count and the list elements won't be freed. All of
2271 * the objects are expected to have non-NULL fini functions.
2274 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2278 Elf_Addr *fini_addr;
2281 assert(root == NULL || root->refcount == 1);
2284 * Preserve the current error message since a fini function might
2285 * call into the dynamic linker and overwrite it.
2287 saved_msg = errmsg_save();
2289 STAILQ_FOREACH(elm, list, link) {
2290 if (root != NULL && (elm->obj->refcount != 1 ||
2291 objlist_find(&root->dagmembers, elm->obj) == NULL))
2294 /* Remove object from fini list to prevent recursive invocation. */
2295 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2297 * XXX: If a dlopen() call references an object while the
2298 * fini function is in progress, we might end up trying to
2299 * unload the referenced object in dlclose() or the object
2300 * won't be unloaded although its fini function has been
2303 lock_release(rtld_bind_lock, lockstate);
2306 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. When this
2307 * happens, DT_FINI_ARRAY is processed first, and it is also processed
2308 * backwards. It is possible to encounter DT_FINI_ARRAY elements with
2309 * values of 0 or 1, but they need to be ignored.
2311 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2312 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2313 for (index = elm->obj->fini_array_num - 1; index >= 0; index--) {
2314 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2315 dbg("calling fini array function for %s at %p",
2316 elm->obj->path, (void *)fini_addr[index]);
2317 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2318 (void *)fini_addr[index], 0, 0, elm->obj->path);
2319 call_initfini_pointer(elm->obj, fini_addr[index]);
2323 if (elm->obj->fini != (Elf_Addr)NULL) {
2324 dbg("calling fini function for %s at %p", elm->obj->path,
2325 (void *)elm->obj->fini);
2326 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2327 0, 0, elm->obj->path);
2328 call_initfini_pointer(elm->obj, elm->obj->fini);
2330 wlock_acquire(rtld_bind_lock, lockstate);
2331 /* No need to free anything if process is going down. */
2335 * We must restart the list traversal after every fini call
2336 * because a dlclose() call from the fini function or from
2337 * another thread might have modified the reference counts.
2341 } while (elm != NULL);
2342 errmsg_restore(saved_msg);
2346 * Call the initialization functions for each of the objects in
2347 * "list". All of the objects are expected to have non-NULL init
2351 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2356 Elf_Addr *init_addr;
2360 * Clean init_scanned flag so that objects can be rechecked and
2361 * possibly initialized earlier if any of vectors called below
2362 * cause the change by using dlopen.
2364 for (obj = obj_list; obj != NULL; obj = obj->next)
2365 obj->init_scanned = false;
2368 * Preserve the current error message since an init function might
2369 * call into the dynamic linker and overwrite it.
2371 saved_msg = errmsg_save();
2372 STAILQ_FOREACH(elm, list, link) {
2373 if (elm->obj->init_done) /* Initialized early. */
2377 * Race: other thread might try to use this object before current
2378 * one completes the initilization. Not much can be done here
2379 * without better locking.
2381 elm->obj->init_done = true;
2382 lock_release(rtld_bind_lock, lockstate);
2385 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. When
2386 * this happens, DT_INIT is processed first. It is possible to
2387 * encounter DT_INIT_ARRAY elements with values of 0 or 1, but they
2388 * need to be ignored.
2390 if (elm->obj->init != (Elf_Addr)NULL) {
2391 dbg("calling init function for %s at %p", elm->obj->path,
2392 (void *)elm->obj->init);
2393 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2394 0, 0, elm->obj->path);
2395 call_initfini_pointer(elm->obj, elm->obj->init);
2397 init_addr = (Elf_Addr *)elm->obj->init_array;
2398 if (init_addr != NULL) {
2399 for (index = 0; index < elm->obj->init_array_num; index++) {
2400 if (init_addr[index] != 0 && init_addr[index] != 1) {
2401 dbg("calling init array function for %s at %p", elm->obj->path,
2402 (void *)init_addr[index]);
2403 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2404 (void *)init_addr[index], 0, 0, elm->obj->path);
2405 call_init_pointer(elm->obj, init_addr[index]);
2409 wlock_acquire(rtld_bind_lock, lockstate);
2411 errmsg_restore(saved_msg);
2415 objlist_clear(Objlist *list)
2419 while (!STAILQ_EMPTY(list)) {
2420 elm = STAILQ_FIRST(list);
2421 STAILQ_REMOVE_HEAD(list, link);
2426 static Objlist_Entry *
2427 objlist_find(Objlist *list, const Obj_Entry *obj)
2431 STAILQ_FOREACH(elm, list, link)
2432 if (elm->obj == obj)
2438 objlist_init(Objlist *list)
2444 objlist_push_head(Objlist *list, Obj_Entry *obj)
2448 elm = NEW(Objlist_Entry);
2450 STAILQ_INSERT_HEAD(list, elm, link);
2454 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2458 elm = NEW(Objlist_Entry);
2460 STAILQ_INSERT_TAIL(list, elm, link);
2464 objlist_remove(Objlist *list, Obj_Entry *obj)
2468 if ((elm = objlist_find(list, obj)) != NULL) {
2469 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2475 * Relocate dag rooted in the specified object.
2476 * Returns 0 on success, or -1 on failure.
2480 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2481 int flags, RtldLockState *lockstate)
2487 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2488 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2497 * Relocate single object.
2498 * Returns 0 on success, or -1 on failure.
2501 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2502 int flags, RtldLockState *lockstate)
2507 obj->relocated = true;
2509 dbg("relocating \"%s\"", obj->path);
2511 if (obj->symtab == NULL || obj->strtab == NULL ||
2512 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2513 _rtld_error("%s: Shared object has no run-time symbol table",
2519 /* There are relocations to the write-protected text segment. */
2520 if (mprotect(obj->mapbase, obj->textsize,
2521 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2522 _rtld_error("%s: Cannot write-enable text segment: %s",
2523 obj->path, rtld_strerror(errno));
2528 /* Process the non-PLT relocations. */
2529 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2533 * Reprotect the text segment. Make sure it is included in the
2534 * core dump since we modified it. This unfortunately causes the
2535 * entire text segment to core-out but we don't have much of a
2536 * choice. We could try to only reenable core dumps on pages
2537 * in which relocations occured but that is likely most of the text
2538 * pages anyway, and even that would not work because the rest of
2539 * the text pages would wind up as a read-only OBJT_DEFAULT object
2540 * (created due to our modifications) backed by the original OBJT_VNODE
2541 * object, and the ELF coredump code is currently only able to dump
2542 * vnode records for pure vnode-backed mappings, not vnode backings
2543 * to memory objects.
2546 madvise(obj->mapbase, obj->textsize, MADV_CORE);
2547 if (mprotect(obj->mapbase, obj->textsize,
2548 PROT_READ|PROT_EXEC) == -1) {
2549 _rtld_error("%s: Cannot write-protect text segment: %s",
2550 obj->path, rtld_strerror(errno));
2556 /* Set the special PLT or GOT entries. */
2559 /* Process the PLT relocations. */
2560 if (reloc_plt(obj) == -1)
2562 /* Relocate the jump slots if we are doing immediate binding. */
2563 if (obj->bind_now || bind_now)
2564 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2568 * Set up the magic number and version in the Obj_Entry. These
2569 * were checked in the crt1.o from the original ElfKit, so we
2570 * set them for backward compatibility.
2572 obj->magic = RTLD_MAGIC;
2573 obj->version = RTLD_VERSION;
2576 * Set relocated data to read-only status if protection specified
2579 if (obj->relro_size) {
2580 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) {
2581 _rtld_error("%s: Cannot enforce relro relocation: %s",
2582 obj->path, rtld_strerror(errno));
2590 * Relocate newly-loaded shared objects. The argument is a pointer to
2591 * the Obj_Entry for the first such object. All objects from the first
2592 * to the end of the list of objects are relocated. Returns 0 on success,
2596 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2597 int flags, RtldLockState *lockstate)
2602 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2603 error = relocate_object(obj, bind_now, rtldobj, flags,
2612 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2613 * referencing STT_GNU_IFUNC symbols is postponed till the other
2614 * relocations are done. The indirect functions specified as
2615 * ifunc are allowed to call other symbols, so we need to have
2616 * objects relocated before asking for resolution from indirects.
2618 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2619 * instead of the usual lazy handling of PLT slots. It is
2620 * consistent with how GNU does it.
2623 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2624 RtldLockState *lockstate)
2626 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2628 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2629 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2635 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2636 RtldLockState *lockstate)
2640 for (obj = first; obj != NULL; obj = obj->next) {
2641 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2648 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2649 RtldLockState *lockstate)
2653 STAILQ_FOREACH(elm, list, link) {
2654 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2662 * Cleanup procedure. It will be called (by the atexit mechanism) just
2663 * before the process exits.
2668 RtldLockState lockstate;
2670 wlock_acquire(rtld_bind_lock, &lockstate);
2672 objlist_call_fini(&list_fini, NULL, &lockstate);
2673 /* No need to remove the items from the list, since we are exiting. */
2674 if (!libmap_disable)
2676 lock_release(rtld_bind_lock, &lockstate);
2680 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2685 path += strspn(path, ":;");
2686 while (*path != '\0') {
2690 len = strcspn(path, ":;");
2691 res = callback(path, len, arg);
2697 path += strspn(path, ":;");
2703 struct try_library_args {
2711 try_library_path(const char *dir, size_t dirlen, void *param)
2713 struct try_library_args *arg;
2716 if (*dir == '/' || trust) {
2719 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2722 pathname = arg->buffer;
2723 strncpy(pathname, dir, dirlen);
2724 pathname[dirlen] = '/';
2725 strcpy(pathname + dirlen + 1, arg->name);
2727 dbg(" Trying \"%s\"", pathname);
2728 if (access(pathname, F_OK) == 0) { /* We found it */
2729 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2730 strcpy(pathname, arg->buffer);
2738 search_library_path(const char *name, const char *path)
2741 struct try_library_args arg;
2747 arg.namelen = strlen(name);
2748 arg.buffer = xmalloc(PATH_MAX);
2749 arg.buflen = PATH_MAX;
2751 p = path_enumerate(path, try_library_path, &arg);
2759 dlclose(void *handle)
2762 RtldLockState lockstate;
2764 wlock_acquire(rtld_bind_lock, &lockstate);
2765 root = dlcheck(handle);
2767 lock_release(rtld_bind_lock, &lockstate);
2770 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2773 /* Unreference the object and its dependencies. */
2774 root->dl_refcount--;
2776 if (root->refcount == 1) {
2778 * The object will be no longer referenced, so we must unload it.
2779 * First, call the fini functions.
2781 objlist_call_fini(&list_fini, root, &lockstate);
2785 /* Finish cleaning up the newly-unreferenced objects. */
2786 GDB_STATE(RT_DELETE,&root->linkmap);
2787 unload_object(root);
2788 GDB_STATE(RT_CONSISTENT,NULL);
2792 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2793 lock_release(rtld_bind_lock, &lockstate);
2800 char *msg = error_message;
2801 error_message = NULL;
2806 dlopen(const char *name, int mode)
2809 return (rtld_dlopen(name, -1, mode));
2813 fdlopen(int fd, int mode)
2816 return (rtld_dlopen(NULL, fd, mode));
2820 rtld_dlopen(const char *name, int fd, int mode)
2822 RtldLockState lockstate;
2825 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2826 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2827 if (ld_tracing != NULL) {
2828 rlock_acquire(rtld_bind_lock, &lockstate);
2829 if (sigsetjmp(lockstate.env, 0) != 0)
2830 lock_upgrade(rtld_bind_lock, &lockstate);
2831 environ = (char **)*get_program_var_addr("environ", &lockstate);
2832 lock_release(rtld_bind_lock, &lockstate);
2834 lo_flags = RTLD_LO_DLOPEN;
2835 if (mode & RTLD_NODELETE)
2836 lo_flags |= RTLD_LO_NODELETE;
2837 if (mode & RTLD_NOLOAD)
2838 lo_flags |= RTLD_LO_NOLOAD;
2839 if (ld_tracing != NULL)
2840 lo_flags |= RTLD_LO_TRACE;
2842 return (dlopen_object(name, fd, obj_main, lo_flags,
2843 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
2847 dlopen_cleanup(Obj_Entry *obj)
2852 if (obj->refcount == 0)
2857 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2858 int mode, RtldLockState *lockstate)
2860 Obj_Entry **old_obj_tail;
2863 RtldLockState mlockstate;
2866 objlist_init(&initlist);
2868 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
2869 wlock_acquire(rtld_bind_lock, &mlockstate);
2870 lockstate = &mlockstate;
2872 GDB_STATE(RT_ADD,NULL);
2874 old_obj_tail = obj_tail;
2876 if (name == NULL && fd == -1) {
2880 obj = load_object(name, fd, refobj, lo_flags);
2885 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2886 objlist_push_tail(&list_global, obj);
2887 if (*old_obj_tail != NULL) { /* We loaded something new. */
2888 assert(*old_obj_tail == obj);
2889 result = load_needed_objects(obj,
2890 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
2894 result = rtld_verify_versions(&obj->dagmembers);
2895 if (result != -1 && ld_tracing)
2897 if (result == -1 || relocate_object_dag(obj,
2898 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
2899 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2901 dlopen_cleanup(obj);
2903 } else if (lo_flags & RTLD_LO_EARLY) {
2905 * Do not call the init functions for early loaded
2906 * filtees. The image is still not initialized enough
2909 * Our object is found by the global object list and
2910 * will be ordered among all init calls done right
2911 * before transferring control to main.
2914 /* Make list of init functions to call. */
2915 initlist_add_objects(obj, &obj->next, &initlist);
2918 * Process all no_delete objects here, given them own
2919 * DAGs to prevent their dependencies from being unloaded.
2920 * This has to be done after we have loaded all of the
2921 * dependencies, so that we do not miss any.
2924 process_nodelete(obj);
2927 * Bump the reference counts for objects on this DAG. If
2928 * this is the first dlopen() call for the object that was
2929 * already loaded as a dependency, initialize the dag
2935 if ((lo_flags & RTLD_LO_TRACE) != 0)
2938 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2939 obj->z_nodelete) && !obj->ref_nodel) {
2940 dbg("obj %s nodelete", obj->path);
2942 obj->z_nodelete = obj->ref_nodel = true;
2946 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2948 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2950 if (!(lo_flags & RTLD_LO_EARLY)) {
2951 map_stacks_exec(lockstate);
2954 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
2955 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2957 objlist_clear(&initlist);
2958 dlopen_cleanup(obj);
2959 if (lockstate == &mlockstate)
2960 lock_release(rtld_bind_lock, lockstate);
2964 if (!(lo_flags & RTLD_LO_EARLY)) {
2965 /* Call the init functions. */
2966 objlist_call_init(&initlist, lockstate);
2968 objlist_clear(&initlist);
2969 if (lockstate == &mlockstate)
2970 lock_release(rtld_bind_lock, lockstate);
2973 trace_loaded_objects(obj);
2974 if (lockstate == &mlockstate)
2975 lock_release(rtld_bind_lock, lockstate);
2980 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
2984 const Obj_Entry *obj, *defobj;
2987 RtldLockState lockstate;
2993 symlook_init(&req, name);
2995 req.flags = flags | SYMLOOK_IN_PLT;
2996 req.lockstate = &lockstate;
2998 rlock_acquire(rtld_bind_lock, &lockstate);
2999 if (sigsetjmp(lockstate.env, 0) != 0)
3000 lock_upgrade(rtld_bind_lock, &lockstate);
3001 if (handle == NULL || handle == RTLD_NEXT ||
3002 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3004 if ((obj = obj_from_addr(retaddr)) == NULL) {
3005 _rtld_error("Cannot determine caller's shared object");
3006 lock_release(rtld_bind_lock, &lockstate);
3009 if (handle == NULL) { /* Just the caller's shared object. */
3010 res = symlook_obj(&req, obj);
3013 defobj = req.defobj_out;
3015 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3016 handle == RTLD_SELF) { /* ... caller included */
3017 if (handle == RTLD_NEXT)
3019 for (; obj != NULL; obj = obj->next) {
3020 res = symlook_obj(&req, obj);
3023 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3025 defobj = req.defobj_out;
3026 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3032 * Search the dynamic linker itself, and possibly resolve the
3033 * symbol from there. This is how the application links to
3034 * dynamic linker services such as dlopen.
3036 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3037 res = symlook_obj(&req, &obj_rtld);
3040 defobj = req.defobj_out;
3044 assert(handle == RTLD_DEFAULT);
3045 res = symlook_default(&req, obj);
3047 defobj = req.defobj_out;
3052 if ((obj = dlcheck(handle)) == NULL) {
3053 lock_release(rtld_bind_lock, &lockstate);
3057 donelist_init(&donelist);
3058 if (obj->mainprog) {
3059 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3060 res = symlook_global(&req, &donelist);
3063 defobj = req.defobj_out;
3066 * Search the dynamic linker itself, and possibly resolve the
3067 * symbol from there. This is how the application links to
3068 * dynamic linker services such as dlopen.
3070 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3071 res = symlook_obj(&req, &obj_rtld);
3074 defobj = req.defobj_out;
3079 /* Search the whole DAG rooted at the given object. */
3080 res = symlook_list(&req, &obj->dagmembers, &donelist);
3083 defobj = req.defobj_out;
3089 lock_release(rtld_bind_lock, &lockstate);
3092 * The value required by the caller is derived from the value
3093 * of the symbol. For the ia64 architecture, we need to
3094 * construct a function descriptor which the caller can use to
3095 * call the function with the right 'gp' value. For other
3096 * architectures and for non-functions, the value is simply
3097 * the relocated value of the symbol.
3099 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3100 return (make_function_pointer(def, defobj));
3101 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3102 return (rtld_resolve_ifunc(defobj, def));
3103 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3104 ti.ti_module = defobj->tlsindex;
3105 ti.ti_offset = def->st_value;
3106 return (__tls_get_addr(&ti));
3108 return (defobj->relocbase + def->st_value);
3111 _rtld_error("Undefined symbol \"%s\"", name);
3112 lock_release(rtld_bind_lock, &lockstate);
3117 dlsym(void *handle, const char *name)
3119 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3124 dlfunc(void *handle, const char *name)
3131 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3137 dlvsym(void *handle, const char *name, const char *version)
3141 ventry.name = version;
3143 ventry.hash = elf_hash(version);
3145 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3150 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3152 const Obj_Entry *obj;
3153 RtldLockState lockstate;
3155 rlock_acquire(rtld_bind_lock, &lockstate);
3156 obj = obj_from_addr(addr);
3158 _rtld_error("No shared object contains address");
3159 lock_release(rtld_bind_lock, &lockstate);
3162 rtld_fill_dl_phdr_info(obj, phdr_info);
3163 lock_release(rtld_bind_lock, &lockstate);
3168 dladdr(const void *addr, Dl_info *info)
3170 const Obj_Entry *obj;
3173 unsigned long symoffset;
3174 RtldLockState lockstate;
3176 rlock_acquire(rtld_bind_lock, &lockstate);
3177 obj = obj_from_addr(addr);
3179 _rtld_error("No shared object contains address");
3180 lock_release(rtld_bind_lock, &lockstate);
3183 info->dli_fname = obj->path;
3184 info->dli_fbase = obj->mapbase;
3185 info->dli_saddr = NULL;
3186 info->dli_sname = NULL;
3189 * Walk the symbol list looking for the symbol whose address is
3190 * closest to the address sent in.
3192 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3193 def = obj->symtab + symoffset;
3196 * For skip the symbol if st_shndx is either SHN_UNDEF or
3199 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3203 * If the symbol is greater than the specified address, or if it
3204 * is further away from addr than the current nearest symbol,
3207 symbol_addr = obj->relocbase + def->st_value;
3208 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3211 /* Update our idea of the nearest symbol. */
3212 info->dli_sname = obj->strtab + def->st_name;
3213 info->dli_saddr = symbol_addr;
3216 if (info->dli_saddr == addr)
3219 lock_release(rtld_bind_lock, &lockstate);
3224 dlinfo(void *handle, int request, void *p)
3226 const Obj_Entry *obj;
3227 RtldLockState lockstate;
3230 rlock_acquire(rtld_bind_lock, &lockstate);
3232 if (handle == NULL || handle == RTLD_SELF) {
3235 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3236 if ((obj = obj_from_addr(retaddr)) == NULL)
3237 _rtld_error("Cannot determine caller's shared object");
3239 obj = dlcheck(handle);
3242 lock_release(rtld_bind_lock, &lockstate);
3248 case RTLD_DI_LINKMAP:
3249 *((struct link_map const **)p) = &obj->linkmap;
3251 case RTLD_DI_ORIGIN:
3252 error = rtld_dirname(obj->path, p);
3255 case RTLD_DI_SERINFOSIZE:
3256 case RTLD_DI_SERINFO:
3257 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3261 _rtld_error("Invalid request %d passed to dlinfo()", request);
3265 lock_release(rtld_bind_lock, &lockstate);
3271 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3274 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3275 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
3276 STAILQ_FIRST(&obj->names)->name : obj->path;
3277 phdr_info->dlpi_phdr = obj->phdr;
3278 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3279 phdr_info->dlpi_tls_modid = obj->tlsindex;
3280 phdr_info->dlpi_tls_data = obj->tlsinit;
3281 phdr_info->dlpi_adds = obj_loads;
3282 phdr_info->dlpi_subs = obj_loads - obj_count;
3286 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3288 struct dl_phdr_info phdr_info;
3289 const Obj_Entry *obj;
3290 RtldLockState bind_lockstate, phdr_lockstate;
3293 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3294 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3298 for (obj = obj_list; obj != NULL; obj = obj->next) {
3299 rtld_fill_dl_phdr_info(obj, &phdr_info);
3300 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3304 lock_release(rtld_bind_lock, &bind_lockstate);
3305 lock_release(rtld_phdr_lock, &phdr_lockstate);
3311 fill_search_info(const char *dir, size_t dirlen, void *param)
3313 struct fill_search_info_args *arg;
3317 if (arg->request == RTLD_DI_SERINFOSIZE) {
3318 arg->serinfo->dls_cnt ++;
3319 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3321 struct dl_serpath *s_entry;
3323 s_entry = arg->serpath;
3324 s_entry->dls_name = arg->strspace;
3325 s_entry->dls_flags = arg->flags;
3327 strncpy(arg->strspace, dir, dirlen);
3328 arg->strspace[dirlen] = '\0';
3330 arg->strspace += dirlen + 1;
3338 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3340 struct dl_serinfo _info;
3341 struct fill_search_info_args args;
3343 args.request = RTLD_DI_SERINFOSIZE;
3344 args.serinfo = &_info;
3346 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3349 path_enumerate(obj->rpath, fill_search_info, &args);
3350 path_enumerate(ld_library_path, fill_search_info, &args);
3351 path_enumerate(obj->runpath, fill_search_info, &args);
3352 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3353 if (!obj->z_nodeflib)
3354 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3357 if (request == RTLD_DI_SERINFOSIZE) {
3358 info->dls_size = _info.dls_size;
3359 info->dls_cnt = _info.dls_cnt;
3363 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3364 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3368 args.request = RTLD_DI_SERINFO;
3369 args.serinfo = info;
3370 args.serpath = &info->dls_serpath[0];
3371 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3373 args.flags = LA_SER_RUNPATH;
3374 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3377 args.flags = LA_SER_LIBPATH;
3378 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3381 args.flags = LA_SER_RUNPATH;
3382 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3385 args.flags = LA_SER_CONFIG;
3386 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3390 args.flags = LA_SER_DEFAULT;
3391 if (!obj->z_nodeflib &&
3392 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3398 rtld_dirname(const char *path, char *bname)
3402 /* Empty or NULL string gets treated as "." */
3403 if (path == NULL || *path == '\0') {
3409 /* Strip trailing slashes */
3410 endp = path + strlen(path) - 1;
3411 while (endp > path && *endp == '/')
3414 /* Find the start of the dir */
3415 while (endp > path && *endp != '/')
3418 /* Either the dir is "/" or there are no slashes */
3420 bname[0] = *endp == '/' ? '/' : '.';
3426 } while (endp > path && *endp == '/');
3429 if (endp - path + 2 > PATH_MAX)
3431 _rtld_error("Filename is too long: %s", path);
3435 strncpy(bname, path, endp - path + 1);
3436 bname[endp - path + 1] = '\0';
3441 rtld_dirname_abs(const char *path, char *base)
3443 char base_rel[PATH_MAX];
3445 if (rtld_dirname(path, base) == -1)
3449 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
3450 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
3451 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
3453 strcpy(base, base_rel);
3458 linkmap_add(Obj_Entry *obj)
3460 struct link_map *l = &obj->linkmap;
3461 struct link_map *prev;
3463 obj->linkmap.l_name = obj->path;
3464 obj->linkmap.l_addr = obj->mapbase;
3465 obj->linkmap.l_ld = obj->dynamic;
3467 /* GDB needs load offset on MIPS to use the symbols */
3468 obj->linkmap.l_offs = obj->relocbase;
3471 if (r_debug.r_map == NULL) {
3477 * Scan to the end of the list, but not past the entry for the
3478 * dynamic linker, which we want to keep at the very end.
3480 for (prev = r_debug.r_map;
3481 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3482 prev = prev->l_next)
3485 /* Link in the new entry. */
3487 l->l_next = prev->l_next;
3488 if (l->l_next != NULL)
3489 l->l_next->l_prev = l;
3494 linkmap_delete(Obj_Entry *obj)
3496 struct link_map *l = &obj->linkmap;
3498 if (l->l_prev == NULL) {
3499 if ((r_debug.r_map = l->l_next) != NULL)
3500 l->l_next->l_prev = NULL;
3504 if ((l->l_prev->l_next = l->l_next) != NULL)
3505 l->l_next->l_prev = l->l_prev;
3509 * Function for the debugger to set a breakpoint on to gain control.
3511 * The two parameters allow the debugger to easily find and determine
3512 * what the runtime loader is doing and to whom it is doing it.
3514 * When the loadhook trap is hit (r_debug_state, set at program
3515 * initialization), the arguments can be found on the stack:
3517 * +8 struct link_map *m
3518 * +4 struct r_debug *rd
3522 r_debug_state(struct r_debug* rd, struct link_map *m)
3525 * The following is a hack to force the compiler to emit calls to
3526 * this function, even when optimizing. If the function is empty,
3527 * the compiler is not obliged to emit any code for calls to it,
3528 * even when marked __noinline. However, gdb depends on those
3531 __asm __volatile("" : : : "memory");
3535 * Get address of the pointer variable in the main program.
3536 * Prefer non-weak symbol over the weak one.
3538 static const void **
3539 get_program_var_addr(const char *name, RtldLockState *lockstate)
3544 symlook_init(&req, name);
3545 req.lockstate = lockstate;
3546 donelist_init(&donelist);
3547 if (symlook_global(&req, &donelist) != 0)
3549 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3550 return ((const void **)make_function_pointer(req.sym_out,
3552 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3553 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3555 return ((const void **)(req.defobj_out->relocbase +
3556 req.sym_out->st_value));
3560 * Set a pointer variable in the main program to the given value. This
3561 * is used to set key variables such as "environ" before any of the
3562 * init functions are called.
3565 set_program_var(const char *name, const void *value)
3569 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3570 dbg("\"%s\": *%p <-- %p", name, addr, value);
3576 * Search the global objects, including dependencies and main object,
3577 * for the given symbol.
3580 symlook_global(SymLook *req, DoneList *donelist)
3583 const Objlist_Entry *elm;
3586 symlook_init_from_req(&req1, req);
3588 /* Search all objects loaded at program start up. */
3589 if (req->defobj_out == NULL ||
3590 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3591 res = symlook_list(&req1, &list_main, donelist);
3592 if (res == 0 && (req->defobj_out == NULL ||
3593 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3594 req->sym_out = req1.sym_out;
3595 req->defobj_out = req1.defobj_out;
3596 assert(req->defobj_out != NULL);
3600 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3601 STAILQ_FOREACH(elm, &list_global, link) {
3602 if (req->defobj_out != NULL &&
3603 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3605 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3606 if (res == 0 && (req->defobj_out == NULL ||
3607 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3608 req->sym_out = req1.sym_out;
3609 req->defobj_out = req1.defobj_out;
3610 assert(req->defobj_out != NULL);
3614 return (req->sym_out != NULL ? 0 : ESRCH);
3618 * This is a special version of getenv which is far more efficient
3619 * at finding LD_ environment vars.
3623 _getenv_ld(const char *id)
3627 int idlen = strlen(id);
3629 if (ld_index == LD_ARY_CACHE)
3631 if (ld_index == 0) {
3632 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) {
3633 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_')
3640 for (i = ld_index - 1; i >= 0; --i) {
3641 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=')
3642 return(ld_ary[i] + idlen + 1);
3648 * Given a symbol name in a referencing object, find the corresponding
3649 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3650 * no definition was found. Returns a pointer to the Obj_Entry of the
3651 * defining object via the reference parameter DEFOBJ_OUT.
3654 symlook_default(SymLook *req, const Obj_Entry *refobj)
3657 const Objlist_Entry *elm;
3661 donelist_init(&donelist);
3662 symlook_init_from_req(&req1, req);
3664 /* Look first in the referencing object if linked symbolically. */
3665 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3666 res = symlook_obj(&req1, refobj);
3668 req->sym_out = req1.sym_out;
3669 req->defobj_out = req1.defobj_out;
3670 assert(req->defobj_out != NULL);
3674 symlook_global(req, &donelist);
3676 /* Search all dlopened DAGs containing the referencing object. */
3677 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3678 if (req->sym_out != NULL &&
3679 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3681 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3682 if (res == 0 && (req->sym_out == NULL ||
3683 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3684 req->sym_out = req1.sym_out;
3685 req->defobj_out = req1.defobj_out;
3686 assert(req->defobj_out != NULL);
3691 * Search the dynamic linker itself, and possibly resolve the
3692 * symbol from there. This is how the application links to
3693 * dynamic linker services such as dlopen.
3695 if (req->sym_out == NULL ||
3696 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3697 res = symlook_obj(&req1, &obj_rtld);
3699 req->sym_out = req1.sym_out;
3700 req->defobj_out = req1.defobj_out;
3701 assert(req->defobj_out != NULL);
3705 return (req->sym_out != NULL ? 0 : ESRCH);
3709 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3712 const Obj_Entry *defobj;
3713 const Objlist_Entry *elm;
3719 STAILQ_FOREACH(elm, objlist, link) {
3720 if (donelist_check(dlp, elm->obj))
3722 symlook_init_from_req(&req1, req);
3723 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3724 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3726 defobj = req1.defobj_out;
3727 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3734 req->defobj_out = defobj;
3741 * Search the chain of DAGS cointed to by the given Needed_Entry
3742 * for a symbol of the given name. Each DAG is scanned completely
3743 * before advancing to the next one. Returns a pointer to the symbol,
3744 * or NULL if no definition was found.
3747 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3750 const Needed_Entry *n;
3751 const Obj_Entry *defobj;
3757 symlook_init_from_req(&req1, req);
3758 for (n = needed; n != NULL; n = n->next) {
3759 if (n->obj == NULL ||
3760 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3762 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3764 defobj = req1.defobj_out;
3765 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3771 req->defobj_out = defobj;
3778 * Search the symbol table of a single shared object for a symbol of
3779 * the given name and version, if requested. Returns a pointer to the
3780 * symbol, or NULL if no definition was found. If the object is
3781 * filter, return filtered symbol from filtee.
3783 * The symbol's hash value is passed in for efficiency reasons; that
3784 * eliminates many recomputations of the hash value.
3787 symlook_obj(SymLook *req, const Obj_Entry *obj)
3791 int flags, res, mres;
3794 * If there is at least one valid hash at this point, we prefer to
3795 * use the faster GNU version if available.
3797 if (obj->valid_hash_gnu)
3798 mres = symlook_obj1_gnu(req, obj);
3799 else if (obj->valid_hash_sysv)
3800 mres = symlook_obj1_sysv(req, obj);
3805 if (obj->needed_filtees != NULL) {
3806 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3807 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3808 donelist_init(&donelist);
3809 symlook_init_from_req(&req1, req);
3810 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3812 req->sym_out = req1.sym_out;
3813 req->defobj_out = req1.defobj_out;
3817 if (obj->needed_aux_filtees != NULL) {
3818 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3819 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3820 donelist_init(&donelist);
3821 symlook_init_from_req(&req1, req);
3822 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3824 req->sym_out = req1.sym_out;
3825 req->defobj_out = req1.defobj_out;
3833 /* Symbol match routine common to both hash functions */
3835 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3836 const unsigned long symnum)
3839 const Elf_Sym *symp;
3842 symp = obj->symtab + symnum;
3843 strp = obj->strtab + symp->st_name;
3845 switch (ELF_ST_TYPE(symp->st_info)) {
3851 if (symp->st_value == 0)
3855 if (symp->st_shndx != SHN_UNDEF)
3857 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3858 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3864 if (strcmp(req->name, strp) != 0)
3867 if (req->ventry == NULL) {
3868 if (obj->versyms != NULL) {
3869 verndx = VER_NDX(obj->versyms[symnum]);
3870 if (verndx > obj->vernum) {
3872 "%s: symbol %s references wrong version %d",
3873 obj->path, obj->strtab + symnum, verndx);
3877 * If we are not called from dlsym (i.e. this
3878 * is a normal relocation from unversioned
3879 * binary), accept the symbol immediately if
3880 * it happens to have first version after this
3881 * shared object became versioned. Otherwise,
3882 * if symbol is versioned and not hidden,
3883 * remember it. If it is the only symbol with
3884 * this name exported by the shared object, it
3885 * will be returned as a match by the calling
3886 * function. If symbol is global (verndx < 2)
3887 * accept it unconditionally.
3889 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3890 verndx == VER_NDX_GIVEN) {
3891 result->sym_out = symp;
3894 else if (verndx >= VER_NDX_GIVEN) {
3895 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
3897 if (result->vsymp == NULL)
3898 result->vsymp = symp;
3904 result->sym_out = symp;
3907 if (obj->versyms == NULL) {
3908 if (object_match_name(obj, req->ventry->name)) {
3909 _rtld_error("%s: object %s should provide version %s "
3910 "for symbol %s", obj_rtld.path, obj->path,
3911 req->ventry->name, obj->strtab + symnum);
3915 verndx = VER_NDX(obj->versyms[symnum]);
3916 if (verndx > obj->vernum) {
3917 _rtld_error("%s: symbol %s references wrong version %d",
3918 obj->path, obj->strtab + symnum, verndx);
3921 if (obj->vertab[verndx].hash != req->ventry->hash ||
3922 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3924 * Version does not match. Look if this is a
3925 * global symbol and if it is not hidden. If
3926 * global symbol (verndx < 2) is available,
3927 * use it. Do not return symbol if we are
3928 * called by dlvsym, because dlvsym looks for
3929 * a specific version and default one is not
3930 * what dlvsym wants.
3932 if ((req->flags & SYMLOOK_DLSYM) ||
3933 (verndx >= VER_NDX_GIVEN) ||
3934 (obj->versyms[symnum] & VER_NDX_HIDDEN))
3938 result->sym_out = symp;
3943 * Search for symbol using SysV hash function.
3944 * obj->buckets is known not to be NULL at this point; the test for this was
3945 * performed with the obj->valid_hash_sysv assignment.
3948 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
3950 unsigned long symnum;
3951 Sym_Match_Result matchres;
3953 matchres.sym_out = NULL;
3954 matchres.vsymp = NULL;
3955 matchres.vcount = 0;
3957 for (symnum = obj->buckets[req->hash % obj->nbuckets];
3958 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
3959 if (symnum >= obj->nchains)
3960 return (ESRCH); /* Bad object */
3962 if (matched_symbol(req, obj, &matchres, symnum)) {
3963 req->sym_out = matchres.sym_out;
3964 req->defobj_out = obj;
3968 if (matchres.vcount == 1) {
3969 req->sym_out = matchres.vsymp;
3970 req->defobj_out = obj;
3976 /* Search for symbol using GNU hash function */
3978 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
3980 Elf_Addr bloom_word;
3981 const Elf32_Word *hashval;
3983 Sym_Match_Result matchres;
3984 unsigned int h1, h2;
3985 unsigned long symnum;
3987 matchres.sym_out = NULL;
3988 matchres.vsymp = NULL;
3989 matchres.vcount = 0;
3991 /* Pick right bitmask word from Bloom filter array */
3992 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
3993 obj->maskwords_bm_gnu];
3995 /* Calculate modulus word size of gnu hash and its derivative */
3996 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
3997 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
3999 /* Filter out the "definitely not in set" queries */
4000 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4003 /* Locate hash chain and corresponding value element*/
4004 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4007 hashval = &obj->chain_zero_gnu[bucket];
4009 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4010 symnum = hashval - obj->chain_zero_gnu;
4011 if (matched_symbol(req, obj, &matchres, symnum)) {
4012 req->sym_out = matchres.sym_out;
4013 req->defobj_out = obj;
4017 } while ((*hashval++ & 1) == 0);
4018 if (matchres.vcount == 1) {
4019 req->sym_out = matchres.vsymp;
4020 req->defobj_out = obj;
4027 trace_loaded_objects(Obj_Entry *obj)
4029 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4032 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
4035 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL)
4036 fmt1 = "\t%o => %p (%x)\n";
4038 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL)
4039 fmt2 = "\t%o (%x)\n";
4041 list_containers = _getenv_ld("LD_TRACE_LOADED_OBJECTS_ALL");
4043 for (; obj; obj = obj->next) {
4044 Needed_Entry *needed;
4048 if (list_containers && obj->needed != NULL)
4049 rtld_printf("%s:\n", obj->path);
4050 for (needed = obj->needed; needed; needed = needed->next) {
4051 if (needed->obj != NULL) {
4052 if (needed->obj->traced && !list_containers)
4054 needed->obj->traced = true;
4055 path = needed->obj->path;
4059 name = (char *)obj->strtab + needed->name;
4060 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4062 fmt = is_lib ? fmt1 : fmt2;
4063 while ((c = *fmt++) != '\0') {
4089 rtld_putstr(main_local);
4092 rtld_putstr(obj_main->path);
4101 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4114 * Unload a dlopened object and its dependencies from memory and from
4115 * our data structures. It is assumed that the DAG rooted in the
4116 * object has already been unreferenced, and that the object has a
4117 * reference count of 0.
4120 unload_object(Obj_Entry *root)
4125 assert(root->refcount == 0);
4128 * Pass over the DAG removing unreferenced objects from
4129 * appropriate lists.
4131 unlink_object(root);
4133 /* Unmap all objects that are no longer referenced. */
4134 linkp = &obj_list->next;
4135 while ((obj = *linkp) != NULL) {
4136 if (obj->refcount == 0) {
4137 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4139 dbg("unloading \"%s\"", obj->path);
4140 unload_filtees(root);
4141 munmap(obj->mapbase, obj->mapsize);
4142 linkmap_delete(obj);
4153 unlink_object(Obj_Entry *root)
4157 if (root->refcount == 0) {
4158 /* Remove the object from the RTLD_GLOBAL list. */
4159 objlist_remove(&list_global, root);
4161 /* Remove the object from all objects' DAG lists. */
4162 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4163 objlist_remove(&elm->obj->dldags, root);
4164 if (elm->obj != root)
4165 unlink_object(elm->obj);
4171 ref_dag(Obj_Entry *root)
4175 assert(root->dag_inited);
4176 STAILQ_FOREACH(elm, &root->dagmembers, link)
4177 elm->obj->refcount++;
4181 unref_dag(Obj_Entry *root)
4185 assert(root->dag_inited);
4186 STAILQ_FOREACH(elm, &root->dagmembers, link)
4187 elm->obj->refcount--;
4191 * Common code for MD __tls_get_addr().
4194 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset)
4196 Elf_Addr* dtv = *dtvp;
4197 RtldLockState lockstate;
4199 /* Check dtv generation in case new modules have arrived */
4200 if (dtv[0] != tls_dtv_generation) {
4204 wlock_acquire(rtld_bind_lock, &lockstate);
4205 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4207 if (to_copy > tls_max_index)
4208 to_copy = tls_max_index;
4209 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4210 newdtv[0] = tls_dtv_generation;
4211 newdtv[1] = tls_max_index;
4213 lock_release(rtld_bind_lock, &lockstate);
4214 dtv = *dtvp = newdtv;
4217 /* Dynamically allocate module TLS if necessary */
4218 if (!dtv[index + 1]) {
4219 /* Signal safe, wlock will block out signals. */
4220 wlock_acquire(rtld_bind_lock, &lockstate);
4221 if (!dtv[index + 1])
4222 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4223 lock_release(rtld_bind_lock, &lockstate);
4225 return (void*) (dtv[index + 1] + offset);
4228 #if defined(RTLD_STATIC_TLS_VARIANT_II)
4231 * Allocate the static TLS area. Return a pointer to the TCB. The
4232 * static area is based on negative offsets relative to the tcb.
4234 * The TCB contains an errno pointer for the system call layer, but because
4235 * we are the RTLD we really have no idea how the caller was compiled so
4236 * the information has to be passed in. errno can either be:
4238 * type 0 errno is a simple non-TLS global pointer.
4239 * (special case for e.g. libc_rtld)
4240 * type 1 errno accessed by GOT entry (dynamically linked programs)
4241 * type 2 errno accessed by %gs:OFFSET (statically linked programs)
4244 allocate_tls(Obj_Entry *objs)
4249 struct tls_tcb *tcb;
4254 * Allocate the new TCB. static TLS storage is placed just before the
4255 * TCB to support the %gs:OFFSET (negative offset) model.
4257 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
4258 ~RTLD_STATIC_TLS_ALIGN_MASK;
4259 tcb = malloc(data_size + sizeof(*tcb));
4260 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */
4262 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr);
4263 dtv = malloc(dtv_size);
4264 bzero(dtv, dtv_size);
4266 #ifdef RTLD_TCB_HAS_SELF_POINTER
4267 tcb->tcb_self = tcb;
4270 tcb->tcb_pthread = NULL;
4272 dtv[0] = tls_dtv_generation;
4273 dtv[1] = tls_max_index;
4275 for (obj = objs; obj; obj = obj->next) {
4276 if (obj->tlsoffset) {
4277 addr = (Elf_Addr)tcb - obj->tlsoffset;
4278 memset((void *)(addr + obj->tlsinitsize),
4279 0, obj->tlssize - obj->tlsinitsize);
4281 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4282 dtv[obj->tlsindex + 1] = addr;
4289 free_tls(struct tls_tcb *tcb)
4293 Elf_Addr tls_start, tls_end;
4296 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
4297 ~RTLD_STATIC_TLS_ALIGN_MASK;
4301 tls_end = (Elf_Addr)tcb;
4302 tls_start = (Elf_Addr)tcb - data_size;
4303 for (i = 0; i < dtv_size; i++) {
4304 if (dtv[i+2] != 0 && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) {
4305 free((void *)dtv[i+2]);
4309 free((void*) tls_start);
4313 #error "Unsupported TLS layout"
4317 * Allocate TLS block for module with given index.
4320 allocate_module_tls(int index)
4325 for (obj = obj_list; obj; obj = obj->next) {
4326 if (obj->tlsindex == index)
4330 _rtld_error("Can't find module with TLS index %d", index);
4334 p = malloc(obj->tlssize);
4336 _rtld_error("Cannot allocate TLS block for index %d", index);
4339 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4340 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4346 allocate_tls_offset(Obj_Entry *obj)
4353 if (obj->tlssize == 0) {
4354 obj->tls_done = true;
4358 if (obj->tlsindex == 1)
4359 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4361 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4362 obj->tlssize, obj->tlsalign);
4365 * If we have already fixed the size of the static TLS block, we
4366 * must stay within that size. When allocating the static TLS, we
4367 * leave a small amount of space spare to be used for dynamically
4368 * loading modules which use static TLS.
4370 if (tls_static_space) {
4371 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4375 tls_last_offset = obj->tlsoffset = off;
4376 tls_last_size = obj->tlssize;
4377 obj->tls_done = true;
4383 free_tls_offset(Obj_Entry *obj)
4385 #ifdef RTLD_STATIC_TLS_VARIANT_II
4387 * If we were the last thing to allocate out of the static TLS
4388 * block, we give our space back to the 'allocator'. This is a
4389 * simplistic workaround to allow libGL.so.1 to be loaded and
4390 * unloaded multiple times. We only handle the Variant II
4391 * mechanism for now - this really needs a proper allocator.
4393 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4394 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4395 tls_last_offset -= obj->tlssize;
4402 _rtld_allocate_tls(void)
4404 struct tls_tcb *new_tcb;
4405 RtldLockState lockstate;
4407 wlock_acquire(rtld_bind_lock, &lockstate);
4408 new_tcb = allocate_tls(obj_list);
4409 lock_release(rtld_bind_lock, &lockstate);
4414 _rtld_free_tls(struct tls_tcb *tcb)
4416 RtldLockState lockstate;
4418 wlock_acquire(rtld_bind_lock, &lockstate);
4420 lock_release(rtld_bind_lock, &lockstate);
4424 object_add_name(Obj_Entry *obj, const char *name)
4430 entry = malloc(sizeof(Name_Entry) + len);
4432 if (entry != NULL) {
4433 strcpy(entry->name, name);
4434 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4439 object_match_name(const Obj_Entry *obj, const char *name)
4443 STAILQ_FOREACH(entry, &obj->names, link) {
4444 if (strcmp(name, entry->name) == 0)
4451 locate_dependency(const Obj_Entry *obj, const char *name)
4453 const Objlist_Entry *entry;
4454 const Needed_Entry *needed;
4456 STAILQ_FOREACH(entry, &list_main, link) {
4457 if (object_match_name(entry->obj, name))
4461 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4462 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4463 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4465 * If there is DT_NEEDED for the name we are looking for,
4466 * we are all set. Note that object might not be found if
4467 * dependency was not loaded yet, so the function can
4468 * return NULL here. This is expected and handled
4469 * properly by the caller.
4471 return (needed->obj);
4474 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4480 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4481 const Elf_Vernaux *vna)
4483 const Elf_Verdef *vd;
4484 const char *vername;
4486 vername = refobj->strtab + vna->vna_name;
4487 vd = depobj->verdef;
4489 _rtld_error("%s: version %s required by %s not defined",
4490 depobj->path, vername, refobj->path);
4494 if (vd->vd_version != VER_DEF_CURRENT) {
4495 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4496 depobj->path, vd->vd_version);
4499 if (vna->vna_hash == vd->vd_hash) {
4500 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4501 ((char *)vd + vd->vd_aux);
4502 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4505 if (vd->vd_next == 0)
4507 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4509 if (vna->vna_flags & VER_FLG_WEAK)
4511 _rtld_error("%s: version %s required by %s not found",
4512 depobj->path, vername, refobj->path);
4517 rtld_verify_object_versions(Obj_Entry *obj)
4519 const Elf_Verneed *vn;
4520 const Elf_Verdef *vd;
4521 const Elf_Verdaux *vda;
4522 const Elf_Vernaux *vna;
4523 const Obj_Entry *depobj;
4524 int maxvernum, vernum;
4526 if (obj->ver_checked)
4528 obj->ver_checked = true;
4532 * Walk over defined and required version records and figure out
4533 * max index used by any of them. Do very basic sanity checking
4537 while (vn != NULL) {
4538 if (vn->vn_version != VER_NEED_CURRENT) {
4539 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4540 obj->path, vn->vn_version);
4543 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4545 vernum = VER_NEED_IDX(vna->vna_other);
4546 if (vernum > maxvernum)
4548 if (vna->vna_next == 0)
4550 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4552 if (vn->vn_next == 0)
4554 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4558 while (vd != NULL) {
4559 if (vd->vd_version != VER_DEF_CURRENT) {
4560 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4561 obj->path, vd->vd_version);
4564 vernum = VER_DEF_IDX(vd->vd_ndx);
4565 if (vernum > maxvernum)
4567 if (vd->vd_next == 0)
4569 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4576 * Store version information in array indexable by version index.
4577 * Verify that object version requirements are satisfied along the
4580 obj->vernum = maxvernum + 1;
4581 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4584 while (vd != NULL) {
4585 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4586 vernum = VER_DEF_IDX(vd->vd_ndx);
4587 assert(vernum <= maxvernum);
4588 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4589 obj->vertab[vernum].hash = vd->vd_hash;
4590 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4591 obj->vertab[vernum].file = NULL;
4592 obj->vertab[vernum].flags = 0;
4594 if (vd->vd_next == 0)
4596 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4600 while (vn != NULL) {
4601 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4604 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4606 if (check_object_provided_version(obj, depobj, vna))
4608 vernum = VER_NEED_IDX(vna->vna_other);
4609 assert(vernum <= maxvernum);
4610 obj->vertab[vernum].hash = vna->vna_hash;
4611 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4612 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4613 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4614 VER_INFO_HIDDEN : 0;
4615 if (vna->vna_next == 0)
4617 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4619 if (vn->vn_next == 0)
4621 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4627 rtld_verify_versions(const Objlist *objlist)
4629 Objlist_Entry *entry;
4633 STAILQ_FOREACH(entry, objlist, link) {
4635 * Skip dummy objects or objects that have their version requirements
4638 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4640 if (rtld_verify_object_versions(entry->obj) == -1) {
4642 if (ld_tracing == NULL)
4646 if (rc == 0 || ld_tracing != NULL)
4647 rc = rtld_verify_object_versions(&obj_rtld);
4652 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4657 vernum = VER_NDX(obj->versyms[symnum]);
4658 if (vernum >= obj->vernum) {
4659 _rtld_error("%s: symbol %s has wrong verneed value %d",
4660 obj->path, obj->strtab + symnum, vernum);
4661 } else if (obj->vertab[vernum].hash != 0) {
4662 return &obj->vertab[vernum];
4669 _rtld_get_stack_prot(void)
4672 return (stack_prot);
4676 map_stacks_exec(RtldLockState *lockstate)
4680 * Stack protection must be implemented in the kernel before the dynamic
4681 * linker can handle PT_GNU_STACK sections.
4682 * The following is the FreeBSD implementation of map_stacks_exec()
4683 * void (*thr_map_stacks_exec)(void);
4685 * if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4687 * thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4688 * get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4689 * if (thr_map_stacks_exec != NULL) {
4690 * stack_prot |= PROT_EXEC;
4691 * thr_map_stacks_exec();
4697 symlook_init(SymLook *dst, const char *name)
4700 bzero(dst, sizeof(*dst));
4702 dst->hash = elf_hash(name);
4703 dst->hash_gnu = gnu_hash(name);
4707 symlook_init_from_req(SymLook *dst, const SymLook *src)
4710 dst->name = src->name;
4711 dst->hash = src->hash;
4712 dst->hash_gnu = src->hash_gnu;
4713 dst->ventry = src->ventry;
4714 dst->flags = src->flags;
4715 dst->defobj_out = NULL;
4716 dst->sym_out = NULL;
4717 dst->lockstate = src->lockstate;
4720 #ifdef ENABLE_OSRELDATE
4722 * Overrides for libc_pic-provided functions.
4726 __getosreldate(void)
4736 oid[1] = KERN_OSRELDATE;
4738 len = sizeof(osrel);
4739 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4740 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4747 * No unresolved symbols for rtld.
4750 __pthread_cxa_finalize(struct dl_phdr_info *a)
4755 rtld_strerror(int errnum)
4758 if (errnum < 0 || errnum >= sys_nerr)
4759 return ("Unknown error");
4760 return (sys_errlist[errnum]);