2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>.
7 * Copyright 2012 John Marino <draco@marino.st>.
8 * Copyright 2014-2017 The FreeBSD Foundation
11 * Portions of this software were developed by Konstantin Belousov
12 * under sponsorship from the FreeBSD Foundation.
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 * Dynamic linker for ELF.
38 * John Polstra <jdp@polstra.com>.
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
44 #include <sys/param.h>
45 #include <sys/mount.h>
48 #include <sys/sysctl.h>
50 #include <sys/utsname.h>
51 #include <sys/ktrace.h>
68 #include "rtld_printf.h"
69 #include "rtld_utrace.h"
73 typedef void (*func_ptr_type)();
74 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
77 * Function declarations.
79 static const char *basename(const char *);
80 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
81 const Elf_Dyn **, const Elf_Dyn **);
82 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
84 static void digest_dynamic(Obj_Entry *, int);
85 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
86 static Obj_Entry *dlcheck(void *);
87 static int dlclose_locked(void *, RtldLockState *);
88 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
89 int lo_flags, int mode, RtldLockState *lockstate);
90 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
91 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
92 static bool donelist_check(DoneList *, const Obj_Entry *);
93 static void errmsg_restore(char *);
94 static char *errmsg_save(void);
95 static void *fill_search_info(const char *, size_t, void *);
96 static char *find_library(const char *, const Obj_Entry *, int *);
97 static const char *gethints(bool);
98 static void hold_object(Obj_Entry *);
99 static void unhold_object(Obj_Entry *);
100 static void init_dag(Obj_Entry *);
101 static void init_marker(Obj_Entry *);
102 static void init_pagesizes(Elf_Auxinfo **aux_info);
103 static void init_rtld(caddr_t, Elf_Auxinfo **);
104 static void initlist_add_neededs(Needed_Entry *, Objlist *);
105 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *);
106 static void linkmap_add(Obj_Entry *);
107 static void linkmap_delete(Obj_Entry *);
108 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
109 static void unload_filtees(Obj_Entry *, RtldLockState *);
110 static int load_needed_objects(Obj_Entry *, int);
111 static int load_preload_objects(void);
112 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
113 static void map_stacks_exec(RtldLockState *);
114 static int obj_enforce_relro(Obj_Entry *);
115 static Obj_Entry *obj_from_addr(const void *);
116 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
117 static void objlist_call_init(Objlist *, RtldLockState *);
118 static void objlist_clear(Objlist *);
119 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
120 static void objlist_init(Objlist *);
121 static void objlist_push_head(Objlist *, Obj_Entry *);
122 static void objlist_push_tail(Objlist *, Obj_Entry *);
123 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
124 static void objlist_remove(Objlist *, Obj_Entry *);
125 static int open_binary_fd(const char *argv0, bool search_in_path);
126 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp);
127 static int parse_integer(const char *);
128 static void *path_enumerate(const char *, path_enum_proc, void *);
129 static void print_usage(const char *argv0);
130 static void release_object(Obj_Entry *);
131 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
132 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
133 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
134 int flags, RtldLockState *lockstate);
135 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
137 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
138 int flags, RtldLockState *lockstate);
139 static int rtld_dirname(const char *, char *);
140 static int rtld_dirname_abs(const char *, char *);
141 static void *rtld_dlopen(const char *name, int fd, int mode);
142 static void rtld_exit(void);
143 static char *search_library_path(const char *, const char *, int *);
144 static char *search_library_pathfds(const char *, const char *, int *);
145 static const void **get_program_var_addr(const char *, RtldLockState *);
146 static void set_program_var(const char *, const void *);
147 static int symlook_default(SymLook *, const Obj_Entry *refobj);
148 static int symlook_global(SymLook *, DoneList *);
149 static void symlook_init_from_req(SymLook *, const SymLook *);
150 static int symlook_list(SymLook *, const Objlist *, DoneList *);
151 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
152 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
153 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
154 static void trace_loaded_objects(Obj_Entry *);
155 static void unlink_object(Obj_Entry *);
156 static void unload_object(Obj_Entry *, RtldLockState *lockstate);
157 static void unref_dag(Obj_Entry *);
158 static void ref_dag(Obj_Entry *);
159 static char *origin_subst_one(Obj_Entry *, char *, const char *,
161 static char *origin_subst(Obj_Entry *, char *);
162 static bool obj_resolve_origin(Obj_Entry *obj);
163 static void preinit_main(void);
164 static int rtld_verify_versions(const Objlist *);
165 static int rtld_verify_object_versions(Obj_Entry *);
166 static void object_add_name(Obj_Entry *, const char *);
167 static int object_match_name(const Obj_Entry *, const char *);
168 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
169 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
170 struct dl_phdr_info *phdr_info);
171 static uint32_t gnu_hash(const char *);
172 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
173 const unsigned long);
175 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
176 void _r_debug_postinit(struct link_map *) __noinline __exported;
178 int __sys_openat(int, const char *, int, ...);
183 static char *error_message; /* Message for dlerror(), or NULL */
184 struct r_debug r_debug __exported; /* for GDB; */
185 static bool libmap_disable; /* Disable libmap */
186 static bool ld_loadfltr; /* Immediate filters processing */
187 static char *libmap_override; /* Maps to use in addition to libmap.conf */
188 static bool trust; /* False for setuid and setgid programs */
189 static bool dangerous_ld_env; /* True if environment variables have been
190 used to affect the libraries loaded */
191 bool ld_bind_not; /* Disable PLT update */
192 static char *ld_bind_now; /* Environment variable for immediate binding */
193 static char *ld_debug; /* Environment variable for debugging */
194 static char *ld_library_path; /* Environment variable for search path */
195 static char *ld_library_dirs; /* Environment variable for library descriptors */
196 static char *ld_preload; /* Environment variable for libraries to
198 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
199 static char *ld_tracing; /* Called from ldd to print libs */
200 static char *ld_utrace; /* Use utrace() to log events. */
201 static struct obj_entry_q obj_list; /* Queue of all loaded objects */
202 static Obj_Entry *obj_main; /* The main program shared object */
203 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
204 static unsigned int obj_count; /* Number of objects in obj_list */
205 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
207 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
208 STAILQ_HEAD_INITIALIZER(list_global);
209 static Objlist list_main = /* Objects loaded at program startup */
210 STAILQ_HEAD_INITIALIZER(list_main);
211 static Objlist list_fini = /* Objects needing fini() calls */
212 STAILQ_HEAD_INITIALIZER(list_fini);
214 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
216 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
218 extern Elf_Dyn _DYNAMIC;
219 #pragma weak _DYNAMIC
221 int dlclose(void *) __exported;
222 char *dlerror(void) __exported;
223 void *dlopen(const char *, int) __exported;
224 void *fdlopen(int, int) __exported;
225 void *dlsym(void *, const char *) __exported;
226 dlfunc_t dlfunc(void *, const char *) __exported;
227 void *dlvsym(void *, const char *, const char *) __exported;
228 int dladdr(const void *, Dl_info *) __exported;
229 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
230 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
231 int dlinfo(void *, int , void *) __exported;
232 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
233 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
234 int _rtld_get_stack_prot(void) __exported;
235 int _rtld_is_dlopened(void *) __exported;
236 void _rtld_error(const char *, ...) __exported;
238 int npagesizes, osreldate;
241 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
242 static int max_stack_flags;
245 * Global declarations normally provided by crt1. The dynamic linker is
246 * not built with crt1, so we have to provide them ourselves.
252 * Used to pass argc, argv to init functions.
258 * Globals to control TLS allocation.
260 size_t tls_last_offset; /* Static TLS offset of last module */
261 size_t tls_last_size; /* Static TLS size of last module */
262 size_t tls_static_space; /* Static TLS space allocated */
263 size_t tls_static_max_align;
264 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
265 int tls_max_index = 1; /* Largest module index allocated */
267 bool ld_library_path_rpath = false;
270 * Globals for path names, and such
272 char *ld_elf_hints_default = _PATH_ELF_HINTS;
273 char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
274 char *ld_path_rtld = _PATH_RTLD;
275 char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
276 char *ld_env_prefix = LD_;
279 * Fill in a DoneList with an allocation large enough to hold all of
280 * the currently-loaded objects. Keep this as a macro since it calls
281 * alloca and we want that to occur within the scope of the caller.
283 #define donelist_init(dlp) \
284 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
285 assert((dlp)->objs != NULL), \
286 (dlp)->num_alloc = obj_count, \
289 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
290 if (ld_utrace != NULL) \
291 ld_utrace_log(e, h, mb, ms, r, n); \
295 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
296 int refcnt, const char *name)
298 struct utrace_rtld ut;
299 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG;
301 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig));
304 ut.mapbase = mapbase;
305 ut.mapsize = mapsize;
307 bzero(ut.name, sizeof(ut.name));
309 strlcpy(ut.name, name, sizeof(ut.name));
310 utrace(&ut, sizeof(ut));
313 #ifdef RTLD_VARIANT_ENV_NAMES
315 * construct the env variable based on the type of binary that's
318 static inline const char *
321 static char buffer[128];
323 strlcpy(buffer, ld_env_prefix, sizeof(buffer));
324 strlcat(buffer, var, sizeof(buffer));
332 * Main entry point for dynamic linking. The first argument is the
333 * stack pointer. The stack is expected to be laid out as described
334 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
335 * Specifically, the stack pointer points to a word containing
336 * ARGC. Following that in the stack is a null-terminated sequence
337 * of pointers to argument strings. Then comes a null-terminated
338 * sequence of pointers to environment strings. Finally, there is a
339 * sequence of "auxiliary vector" entries.
341 * The second argument points to a place to store the dynamic linker's
342 * exit procedure pointer and the third to a place to store the main
345 * The return value is the main program's entry point.
348 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
350 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT];
351 Objlist_Entry *entry;
352 Obj_Entry *last_interposer, *obj, *preload_tail;
353 const Elf_Phdr *phdr;
355 RtldLockState lockstate;
358 char **argv, *argv0, **env, **envp, *kexecpath, *library_path_rpath;
360 char buf[MAXPATHLEN];
361 int argc, fd, i, phnum, rtld_argc;
362 bool dir_enable, explicit_fd, search_in_path;
365 * On entry, the dynamic linker itself has not been relocated yet.
366 * Be very careful not to reference any global data until after
367 * init_rtld has returned. It is OK to reference file-scope statics
368 * and string constants, and to call static and global functions.
371 /* Find the auxiliary vector on the stack. */
375 sp += argc + 1; /* Skip over arguments and NULL terminator */
377 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
379 aux = (Elf_Auxinfo *) sp;
381 /* Digest the auxiliary vector. */
382 for (i = 0; i < AT_COUNT; i++)
384 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
385 if (auxp->a_type < AT_COUNT)
386 aux_info[auxp->a_type] = auxp;
389 /* Initialize and relocate ourselves. */
390 assert(aux_info[AT_BASE] != NULL);
391 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
393 __progname = obj_rtld.path;
394 argv0 = argv[0] != NULL ? argv[0] : "(null)";
399 trust = !issetugid();
401 md_abi_variant_hook(aux_info);
404 if (aux_info[AT_EXECFD] != NULL) {
405 fd = aux_info[AT_EXECFD]->a_un.a_val;
407 assert(aux_info[AT_PHDR] != NULL);
408 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
409 if (phdr == obj_rtld.phdr) {
411 rtld_printf("Tainted process refusing to run binary %s\n",
415 dbg("opening main program in direct exec mode");
417 rtld_argc = parse_args(argv, argc, &search_in_path, &fd);
418 argv0 = argv[rtld_argc];
419 explicit_fd = (fd != -1);
421 fd = open_binary_fd(argv0, search_in_path);
422 if (fstat(fd, &st) == -1) {
423 _rtld_error("failed to fstat FD %d (%s): %s", fd,
424 explicit_fd ? "user-provided descriptor" : argv0,
425 rtld_strerror(errno));
430 * Rough emulation of the permission checks done by
431 * execve(2), only Unix DACs are checked, ACLs are
432 * ignored. Preserve the semantic of disabling owner
433 * to execute if owner x bit is cleared, even if
434 * others x bit is enabled.
435 * mmap(2) does not allow to mmap with PROT_EXEC if
436 * binary' file comes from noexec mount. We cannot
437 * set VV_TEXT on the binary.
440 if (st.st_uid == geteuid()) {
441 if ((st.st_mode & S_IXUSR) != 0)
443 } else if (st.st_gid == getegid()) {
444 if ((st.st_mode & S_IXGRP) != 0)
446 } else if ((st.st_mode & S_IXOTH) != 0) {
450 rtld_printf("No execute permission for binary %s\n",
456 * For direct exec mode, argv[0] is the interpreter
457 * name, we must remove it and shift arguments left
458 * before invoking binary main. Since stack layout
459 * places environment pointers and aux vectors right
460 * after the terminating NULL, we must shift
461 * environment and aux as well.
463 main_argc = argc - rtld_argc;
464 for (i = 0; i <= main_argc; i++)
465 argv[i] = argv[i + rtld_argc];
467 environ = env = envp = argv + main_argc + 1;
469 *envp = *(envp + rtld_argc);
471 } while (*envp != NULL);
472 aux = auxp = (Elf_Auxinfo *)envp;
473 auxpf = (Elf_Auxinfo *)(envp + rtld_argc);
474 for (;; auxp++, auxpf++) {
476 if (auxp->a_type == AT_NULL)
480 rtld_printf("no binary\n");
486 ld_bind_now = getenv(_LD("BIND_NOW"));
489 * If the process is tainted, then we un-set the dangerous environment
490 * variables. The process will be marked as tainted until setuid(2)
491 * is called. If any child process calls setuid(2) we do not want any
492 * future processes to honor the potentially un-safe variables.
495 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) ||
496 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) ||
497 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) ||
498 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) ||
499 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) {
500 _rtld_error("environment corrupt; aborting");
504 ld_debug = getenv(_LD("DEBUG"));
505 if (ld_bind_now == NULL)
506 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL;
507 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL;
508 libmap_override = getenv(_LD("LIBMAP"));
509 ld_library_path = getenv(_LD("LIBRARY_PATH"));
510 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS"));
511 ld_preload = getenv(_LD("PRELOAD"));
512 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH"));
513 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL;
514 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH"));
515 if (library_path_rpath != NULL) {
516 if (library_path_rpath[0] == 'y' ||
517 library_path_rpath[0] == 'Y' ||
518 library_path_rpath[0] == '1')
519 ld_library_path_rpath = true;
521 ld_library_path_rpath = false;
523 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
524 (ld_library_path != NULL) || (ld_preload != NULL) ||
525 (ld_elf_hints_path != NULL) || ld_loadfltr;
526 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS"));
527 ld_utrace = getenv(_LD("UTRACE"));
529 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
530 ld_elf_hints_path = ld_elf_hints_default;
532 if (ld_debug != NULL && *ld_debug != '\0')
534 dbg("%s is initialized, base address = %p", __progname,
535 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
536 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
537 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
539 dbg("initializing thread locks");
543 * Load the main program, or process its program header if it is
546 if (fd != -1) { /* Load the main program. */
547 dbg("loading main program");
548 obj_main = map_object(fd, argv0, NULL);
550 if (obj_main == NULL)
552 max_stack_flags = obj_main->stack_flags;
553 } else { /* Main program already loaded. */
554 dbg("processing main program's program header");
555 assert(aux_info[AT_PHDR] != NULL);
556 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
557 assert(aux_info[AT_PHNUM] != NULL);
558 phnum = aux_info[AT_PHNUM]->a_un.a_val;
559 assert(aux_info[AT_PHENT] != NULL);
560 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
561 assert(aux_info[AT_ENTRY] != NULL);
562 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
563 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL)
567 if (aux_info[AT_EXECPATH] != NULL && fd == -1) {
568 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
569 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
570 if (kexecpath[0] == '/')
571 obj_main->path = kexecpath;
572 else if (getcwd(buf, sizeof(buf)) == NULL ||
573 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
574 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
575 obj_main->path = xstrdup(argv0);
577 obj_main->path = xstrdup(buf);
579 dbg("No AT_EXECPATH or direct exec");
580 obj_main->path = xstrdup(argv0);
582 dbg("obj_main path %s", obj_main->path);
583 obj_main->mainprog = true;
585 if (aux_info[AT_STACKPROT] != NULL &&
586 aux_info[AT_STACKPROT]->a_un.a_val != 0)
587 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
591 * Get the actual dynamic linker pathname from the executable if
592 * possible. (It should always be possible.) That ensures that
593 * gdb will find the right dynamic linker even if a non-standard
596 if (obj_main->interp != NULL &&
597 strcmp(obj_main->interp, obj_rtld.path) != 0) {
599 obj_rtld.path = xstrdup(obj_main->interp);
600 __progname = obj_rtld.path;
604 digest_dynamic(obj_main, 0);
605 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
606 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
607 obj_main->dynsymcount);
609 linkmap_add(obj_main);
610 linkmap_add(&obj_rtld);
612 /* Link the main program into the list of objects. */
613 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
617 /* Initialize a fake symbol for resolving undefined weak references. */
618 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
619 sym_zero.st_shndx = SHN_UNDEF;
620 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
623 libmap_disable = (bool)lm_init(libmap_override);
625 dbg("loading LD_PRELOAD libraries");
626 if (load_preload_objects() == -1)
628 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
630 dbg("loading needed objects");
631 if (load_needed_objects(obj_main, 0) == -1)
634 /* Make a list of all objects loaded at startup. */
635 last_interposer = obj_main;
636 TAILQ_FOREACH(obj, &obj_list, next) {
639 if (obj->z_interpose && obj != obj_main) {
640 objlist_put_after(&list_main, last_interposer, obj);
641 last_interposer = obj;
643 objlist_push_tail(&list_main, obj);
648 dbg("checking for required versions");
649 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
652 if (ld_tracing) { /* We're done */
653 trace_loaded_objects(obj_main);
657 if (getenv(_LD("DUMP_REL_PRE")) != NULL) {
658 dump_relocations(obj_main);
663 * Processing tls relocations requires having the tls offsets
664 * initialized. Prepare offsets before starting initial
665 * relocation processing.
667 dbg("initializing initial thread local storage offsets");
668 STAILQ_FOREACH(entry, &list_main, link) {
670 * Allocate all the initial objects out of the static TLS
671 * block even if they didn't ask for it.
673 allocate_tls_offset(entry->obj);
676 if (relocate_objects(obj_main,
677 ld_bind_now != NULL && *ld_bind_now != '\0',
678 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
681 dbg("doing copy relocations");
682 if (do_copy_relocations(obj_main) == -1)
685 dbg("enforcing main obj relro");
686 if (obj_enforce_relro(obj_main) == -1)
689 if (getenv(_LD("DUMP_REL_POST")) != NULL) {
690 dump_relocations(obj_main);
695 * Setup TLS for main thread. This must be done after the
696 * relocations are processed, since tls initialization section
697 * might be the subject for relocations.
699 dbg("initializing initial thread local storage");
700 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
702 dbg("initializing key program variables");
703 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
704 set_program_var("environ", env);
705 set_program_var("__elf_aux_vector", aux);
707 /* Make a list of init functions to call. */
708 objlist_init(&initlist);
709 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)),
710 preload_tail, &initlist);
712 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
714 map_stacks_exec(NULL);
717 dbg("resolving ifuncs");
718 if (resolve_objects_ifunc(obj_main,
719 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
723 if (!obj_main->crt_no_init) {
725 * Make sure we don't call the main program's init and fini
726 * functions for binaries linked with old crt1 which calls
729 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
730 obj_main->preinit_array = obj_main->init_array =
731 obj_main->fini_array = (Elf_Addr)NULL;
735 * Execute MD initializers required before we call the objects'
740 wlock_acquire(rtld_bind_lock, &lockstate);
741 if (obj_main->crt_no_init)
743 objlist_call_init(&initlist, &lockstate);
744 _r_debug_postinit(&obj_main->linkmap);
745 objlist_clear(&initlist);
746 dbg("loading filtees");
747 TAILQ_FOREACH(obj, &obj_list, next) {
750 if (ld_loadfltr || obj->z_loadfltr)
751 load_filtees(obj, 0, &lockstate);
753 lock_release(rtld_bind_lock, &lockstate);
755 dbg("transferring control to program entry point = %p", obj_main->entry);
757 /* Return the exit procedure and the program entry point. */
758 *exit_proc = rtld_exit;
760 return (func_ptr_type) obj_main->entry;
764 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
769 ptr = (void *)make_function_pointer(def, obj);
770 target = call_ifunc_resolver(ptr);
771 return ((void *)target);
775 * NB: MIPS uses a private version of this function (_mips_rtld_bind).
776 * Changes to this function should be applied there as well.
779 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
783 const Obj_Entry *defobj;
786 RtldLockState lockstate;
788 rlock_acquire(rtld_bind_lock, &lockstate);
789 if (sigsetjmp(lockstate.env, 0) != 0)
790 lock_upgrade(rtld_bind_lock, &lockstate);
792 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
794 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
796 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
797 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
801 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
802 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
804 target = (Elf_Addr)(defobj->relocbase + def->st_value);
806 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
807 defobj->strtab + def->st_name, basename(obj->path),
808 (void *)target, basename(defobj->path));
811 * Write the new contents for the jmpslot. Note that depending on
812 * architecture, the value which we need to return back to the
813 * lazy binding trampoline may or may not be the target
814 * address. The value returned from reloc_jmpslot() is the value
815 * that the trampoline needs.
817 target = reloc_jmpslot(where, target, defobj, obj, rel);
818 lock_release(rtld_bind_lock, &lockstate);
823 * Error reporting function. Use it like printf. If formats the message
824 * into a buffer, and sets things up so that the next call to dlerror()
825 * will return the message.
828 _rtld_error(const char *fmt, ...)
830 static char buf[512];
834 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
837 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message);
841 * Return a dynamically-allocated copy of the current error message, if any.
846 return error_message == NULL ? NULL : xstrdup(error_message);
850 * Restore the current error message from a copy which was previously saved
851 * by errmsg_save(). The copy is freed.
854 errmsg_restore(char *saved_msg)
856 if (saved_msg == NULL)
857 error_message = NULL;
859 _rtld_error("%s", saved_msg);
865 basename(const char *name)
867 const char *p = strrchr(name, '/');
868 return p != NULL ? p + 1 : name;
871 static struct utsname uts;
874 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
875 const char *subst, bool may_free)
877 char *p, *p1, *res, *resp;
878 int subst_len, kw_len, subst_count, old_len, new_len;
883 * First, count the number of the keyword occurrences, to
884 * preallocate the final string.
886 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
893 * If the keyword is not found, just return.
895 * Return non-substituted string if resolution failed. We
896 * cannot do anything more reasonable, the failure mode of the
897 * caller is unresolved library anyway.
899 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
900 return (may_free ? real : xstrdup(real));
902 subst = obj->origin_path;
905 * There is indeed something to substitute. Calculate the
906 * length of the resulting string, and allocate it.
908 subst_len = strlen(subst);
909 old_len = strlen(real);
910 new_len = old_len + (subst_len - kw_len) * subst_count;
911 res = xmalloc(new_len + 1);
914 * Now, execute the substitution loop.
916 for (p = real, resp = res, *resp = '\0';;) {
919 /* Copy the prefix before keyword. */
920 memcpy(resp, p, p1 - p);
922 /* Keyword replacement. */
923 memcpy(resp, subst, subst_len);
931 /* Copy to the end of string and finish. */
939 origin_subst(Obj_Entry *obj, char *real)
941 char *res1, *res2, *res3, *res4;
943 if (obj == NULL || !trust)
944 return (xstrdup(real));
945 if (uts.sysname[0] == '\0') {
946 if (uname(&uts) != 0) {
947 _rtld_error("utsname failed: %d", errno);
951 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false);
952 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
953 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
954 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
961 const char *msg = dlerror();
965 rtld_fdputstr(STDERR_FILENO, msg);
966 rtld_fdputchar(STDERR_FILENO, '\n');
971 * Process a shared object's DYNAMIC section, and save the important
972 * information in its Obj_Entry structure.
975 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
976 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
979 Needed_Entry **needed_tail = &obj->needed;
980 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
981 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
982 const Elf_Hashelt *hashtab;
983 const Elf32_Word *hashval;
984 Elf32_Word bkt, nmaskwords;
986 int plttype = DT_REL;
992 obj->bind_now = false;
993 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
994 switch (dynp->d_tag) {
997 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
1001 obj->relsize = dynp->d_un.d_val;
1005 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1009 obj->pltrel = (const Elf_Rel *)
1010 (obj->relocbase + dynp->d_un.d_ptr);
1014 obj->pltrelsize = dynp->d_un.d_val;
1018 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
1022 obj->relasize = dynp->d_un.d_val;
1026 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1030 plttype = dynp->d_un.d_val;
1031 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1035 obj->symtab = (const Elf_Sym *)
1036 (obj->relocbase + dynp->d_un.d_ptr);
1040 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1044 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
1048 obj->strsize = dynp->d_un.d_val;
1052 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
1057 obj->verneednum = dynp->d_un.d_val;
1061 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
1066 obj->verdefnum = dynp->d_un.d_val;
1070 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1076 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1078 obj->nbuckets = hashtab[0];
1079 obj->nchains = hashtab[1];
1080 obj->buckets = hashtab + 2;
1081 obj->chains = obj->buckets + obj->nbuckets;
1082 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1083 obj->buckets != NULL;
1089 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1091 obj->nbuckets_gnu = hashtab[0];
1092 obj->symndx_gnu = hashtab[1];
1093 nmaskwords = hashtab[2];
1094 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1095 obj->maskwords_bm_gnu = nmaskwords - 1;
1096 obj->shift2_gnu = hashtab[3];
1097 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
1098 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1099 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1101 /* Number of bitmask words is required to be power of 2 */
1102 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1103 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1109 Needed_Entry *nep = NEW(Needed_Entry);
1110 nep->name = dynp->d_un.d_val;
1115 needed_tail = &nep->next;
1121 Needed_Entry *nep = NEW(Needed_Entry);
1122 nep->name = dynp->d_un.d_val;
1126 *needed_filtees_tail = nep;
1127 needed_filtees_tail = &nep->next;
1133 Needed_Entry *nep = NEW(Needed_Entry);
1134 nep->name = dynp->d_un.d_val;
1138 *needed_aux_filtees_tail = nep;
1139 needed_aux_filtees_tail = &nep->next;
1144 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1148 obj->textrel = true;
1152 obj->symbolic = true;
1157 * We have to wait until later to process this, because we
1158 * might not have gotten the address of the string table yet.
1168 *dyn_runpath = dynp;
1172 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1175 case DT_PREINIT_ARRAY:
1176 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1179 case DT_PREINIT_ARRAYSZ:
1180 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1184 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1187 case DT_INIT_ARRAYSZ:
1188 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1192 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1196 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1199 case DT_FINI_ARRAYSZ:
1200 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1204 * Don't process DT_DEBUG on MIPS as the dynamic section
1205 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1211 dbg("Filling in DT_DEBUG entry");
1212 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1217 if (dynp->d_un.d_val & DF_ORIGIN)
1218 obj->z_origin = true;
1219 if (dynp->d_un.d_val & DF_SYMBOLIC)
1220 obj->symbolic = true;
1221 if (dynp->d_un.d_val & DF_TEXTREL)
1222 obj->textrel = true;
1223 if (dynp->d_un.d_val & DF_BIND_NOW)
1224 obj->bind_now = true;
1225 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1229 case DT_MIPS_LOCAL_GOTNO:
1230 obj->local_gotno = dynp->d_un.d_val;
1233 case DT_MIPS_SYMTABNO:
1234 obj->symtabno = dynp->d_un.d_val;
1237 case DT_MIPS_GOTSYM:
1238 obj->gotsym = dynp->d_un.d_val;
1241 case DT_MIPS_RLD_MAP:
1242 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1245 case DT_MIPS_PLTGOT:
1246 obj->mips_pltgot = (Elf_Addr *) (obj->relocbase +
1252 #ifdef __powerpc64__
1253 case DT_PPC64_GLINK:
1254 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1259 if (dynp->d_un.d_val & DF_1_NOOPEN)
1260 obj->z_noopen = true;
1261 if (dynp->d_un.d_val & DF_1_ORIGIN)
1262 obj->z_origin = true;
1263 if (dynp->d_un.d_val & DF_1_GLOBAL)
1264 obj->z_global = true;
1265 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1266 obj->bind_now = true;
1267 if (dynp->d_un.d_val & DF_1_NODELETE)
1268 obj->z_nodelete = true;
1269 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1270 obj->z_loadfltr = true;
1271 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1272 obj->z_interpose = true;
1273 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1274 obj->z_nodeflib = true;
1279 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1286 obj->traced = false;
1288 if (plttype == DT_RELA) {
1289 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1291 obj->pltrelasize = obj->pltrelsize;
1292 obj->pltrelsize = 0;
1295 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1296 if (obj->valid_hash_sysv)
1297 obj->dynsymcount = obj->nchains;
1298 else if (obj->valid_hash_gnu) {
1299 obj->dynsymcount = 0;
1300 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1301 if (obj->buckets_gnu[bkt] == 0)
1303 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1306 while ((*hashval++ & 1u) == 0);
1308 obj->dynsymcount += obj->symndx_gnu;
1313 obj_resolve_origin(Obj_Entry *obj)
1316 if (obj->origin_path != NULL)
1318 obj->origin_path = xmalloc(PATH_MAX);
1319 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1323 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1324 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1327 if (obj->z_origin && !obj_resolve_origin(obj))
1330 if (dyn_runpath != NULL) {
1331 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1332 obj->runpath = origin_subst(obj, obj->runpath);
1333 } else if (dyn_rpath != NULL) {
1334 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1335 obj->rpath = origin_subst(obj, obj->rpath);
1337 if (dyn_soname != NULL)
1338 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1342 digest_dynamic(Obj_Entry *obj, int early)
1344 const Elf_Dyn *dyn_rpath;
1345 const Elf_Dyn *dyn_soname;
1346 const Elf_Dyn *dyn_runpath;
1348 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1349 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1353 * Process a shared object's program header. This is used only for the
1354 * main program, when the kernel has already loaded the main program
1355 * into memory before calling the dynamic linker. It creates and
1356 * returns an Obj_Entry structure.
1359 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1362 const Elf_Phdr *phlimit = phdr + phnum;
1364 Elf_Addr note_start, note_end;
1368 for (ph = phdr; ph < phlimit; ph++) {
1369 if (ph->p_type != PT_PHDR)
1373 obj->phsize = ph->p_memsz;
1374 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1378 obj->stack_flags = PF_X | PF_R | PF_W;
1380 for (ph = phdr; ph < phlimit; ph++) {
1381 switch (ph->p_type) {
1384 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1388 if (nsegs == 0) { /* First load segment */
1389 obj->vaddrbase = trunc_page(ph->p_vaddr);
1390 obj->mapbase = obj->vaddrbase + obj->relocbase;
1391 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1393 } else { /* Last load segment */
1394 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1401 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1406 obj->tlssize = ph->p_memsz;
1407 obj->tlsalign = ph->p_align;
1408 obj->tlsinitsize = ph->p_filesz;
1409 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1413 obj->stack_flags = ph->p_flags;
1417 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1418 obj->relro_size = round_page(ph->p_memsz);
1422 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1423 note_end = note_start + ph->p_filesz;
1424 digest_notes(obj, note_start, note_end);
1429 _rtld_error("%s: too few PT_LOAD segments", path);
1438 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1440 const Elf_Note *note;
1441 const char *note_name;
1444 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1445 note = (const Elf_Note *)((const char *)(note + 1) +
1446 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1447 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1448 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1449 note->n_descsz != sizeof(int32_t))
1451 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1452 note->n_type != NT_FREEBSD_NOINIT_TAG)
1454 note_name = (const char *)(note + 1);
1455 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1456 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1458 switch (note->n_type) {
1459 case NT_FREEBSD_ABI_TAG:
1460 /* FreeBSD osrel note */
1461 p = (uintptr_t)(note + 1);
1462 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1463 obj->osrel = *(const int32_t *)(p);
1464 dbg("note osrel %d", obj->osrel);
1466 case NT_FREEBSD_NOINIT_TAG:
1467 /* FreeBSD 'crt does not call init' note */
1468 obj->crt_no_init = true;
1469 dbg("note crt_no_init");
1476 dlcheck(void *handle)
1480 TAILQ_FOREACH(obj, &obj_list, next) {
1481 if (obj == (Obj_Entry *) handle)
1485 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1486 _rtld_error("Invalid shared object handle %p", handle);
1493 * If the given object is already in the donelist, return true. Otherwise
1494 * add the object to the list and return false.
1497 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1501 for (i = 0; i < dlp->num_used; i++)
1502 if (dlp->objs[i] == obj)
1505 * Our donelist allocation should always be sufficient. But if
1506 * our threads locking isn't working properly, more shared objects
1507 * could have been loaded since we allocated the list. That should
1508 * never happen, but we'll handle it properly just in case it does.
1510 if (dlp->num_used < dlp->num_alloc)
1511 dlp->objs[dlp->num_used++] = obj;
1516 * Hash function for symbol table lookup. Don't even think about changing
1517 * this. It is specified by the System V ABI.
1520 elf_hash(const char *name)
1522 const unsigned char *p = (const unsigned char *) name;
1523 unsigned long h = 0;
1526 while (*p != '\0') {
1527 h = (h << 4) + *p++;
1528 if ((g = h & 0xf0000000) != 0)
1536 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1537 * unsigned in case it's implemented with a wider type.
1540 gnu_hash(const char *s)
1546 for (c = *s; c != '\0'; c = *++s)
1548 return (h & 0xffffffff);
1553 * Find the library with the given name, and return its full pathname.
1554 * The returned string is dynamically allocated. Generates an error
1555 * message and returns NULL if the library cannot be found.
1557 * If the second argument is non-NULL, then it refers to an already-
1558 * loaded shared object, whose library search path will be searched.
1560 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1561 * descriptor (which is close-on-exec) will be passed out via the third
1564 * The search order is:
1565 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1566 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1568 * DT_RUNPATH in the referencing file
1569 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1571 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1573 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1576 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1580 bool nodeflib, objgiven;
1582 objgiven = refobj != NULL;
1584 if (libmap_disable || !objgiven ||
1585 (name = lm_find(refobj->path, xname)) == NULL)
1586 name = (char *)xname;
1588 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1589 if (name[0] != '/' && !trust) {
1590 _rtld_error("Absolute pathname required "
1591 "for shared object \"%s\"", name);
1594 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1595 __DECONST(char *, name)));
1598 dbg(" Searching for \"%s\"", name);
1601 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1602 * back to pre-conforming behaviour if user requested so with
1603 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1606 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1607 pathname = search_library_path(name, ld_library_path, fdp);
1608 if (pathname != NULL)
1610 if (refobj != NULL) {
1611 pathname = search_library_path(name, refobj->rpath, fdp);
1612 if (pathname != NULL)
1615 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1616 if (pathname != NULL)
1618 pathname = search_library_path(name, gethints(false), fdp);
1619 if (pathname != NULL)
1621 pathname = search_library_path(name, ld_standard_library_path, fdp);
1622 if (pathname != NULL)
1625 nodeflib = objgiven ? refobj->z_nodeflib : false;
1627 pathname = search_library_path(name, refobj->rpath, fdp);
1628 if (pathname != NULL)
1631 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1632 pathname = search_library_path(name, obj_main->rpath, fdp);
1633 if (pathname != NULL)
1636 pathname = search_library_path(name, ld_library_path, fdp);
1637 if (pathname != NULL)
1640 pathname = search_library_path(name, refobj->runpath, fdp);
1641 if (pathname != NULL)
1644 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1645 if (pathname != NULL)
1647 pathname = search_library_path(name, gethints(nodeflib), fdp);
1648 if (pathname != NULL)
1650 if (objgiven && !nodeflib) {
1651 pathname = search_library_path(name,
1652 ld_standard_library_path, fdp);
1653 if (pathname != NULL)
1658 if (objgiven && refobj->path != NULL) {
1659 _rtld_error("Shared object \"%s\" not found, "
1660 "required by \"%s\"", name, basename(refobj->path));
1662 _rtld_error("Shared object \"%s\" not found", name);
1668 * Given a symbol number in a referencing object, find the corresponding
1669 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1670 * no definition was found. Returns a pointer to the Obj_Entry of the
1671 * defining object via the reference parameter DEFOBJ_OUT.
1674 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1675 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1676 RtldLockState *lockstate)
1680 const Obj_Entry *defobj;
1681 const Ver_Entry *ve;
1687 * If we have already found this symbol, get the information from
1690 if (symnum >= refobj->dynsymcount)
1691 return NULL; /* Bad object */
1692 if (cache != NULL && cache[symnum].sym != NULL) {
1693 *defobj_out = cache[symnum].obj;
1694 return cache[symnum].sym;
1697 ref = refobj->symtab + symnum;
1698 name = refobj->strtab + ref->st_name;
1704 * We don't have to do a full scale lookup if the symbol is local.
1705 * We know it will bind to the instance in this load module; to
1706 * which we already have a pointer (ie ref). By not doing a lookup,
1707 * we not only improve performance, but it also avoids unresolvable
1708 * symbols when local symbols are not in the hash table. This has
1709 * been seen with the ia64 toolchain.
1711 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1712 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1713 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1716 symlook_init(&req, name);
1718 ve = req.ventry = fetch_ventry(refobj, symnum);
1719 req.lockstate = lockstate;
1720 res = symlook_default(&req, refobj);
1723 defobj = req.defobj_out;
1731 * If we found no definition and the reference is weak, treat the
1732 * symbol as having the value zero.
1734 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1740 *defobj_out = defobj;
1741 /* Record the information in the cache to avoid subsequent lookups. */
1742 if (cache != NULL) {
1743 cache[symnum].sym = def;
1744 cache[symnum].obj = defobj;
1747 if (refobj != &obj_rtld)
1748 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name,
1749 ve != NULL ? "@" : "", ve != NULL ? ve->name : "");
1755 * Return the search path from the ldconfig hints file, reading it if
1756 * necessary. If nostdlib is true, then the default search paths are
1757 * not added to result.
1759 * Returns NULL if there are problems with the hints file,
1760 * or if the search path there is empty.
1763 gethints(bool nostdlib)
1765 static char *hints, *filtered_path;
1766 static struct elfhints_hdr hdr;
1767 struct fill_search_info_args sargs, hargs;
1768 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1769 struct dl_serpath *SLPpath, *hintpath;
1771 struct stat hint_stat;
1772 unsigned int SLPndx, hintndx, fndx, fcount;
1778 /* First call, read the hints file */
1779 if (hints == NULL) {
1780 /* Keep from trying again in case the hints file is bad. */
1783 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1787 * Check of hdr.dirlistlen value against type limit
1788 * intends to pacify static analyzers. Further
1789 * paranoia leads to checks that dirlist is fully
1790 * contained in the file range.
1792 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1793 hdr.magic != ELFHINTS_MAGIC ||
1794 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 ||
1795 fstat(fd, &hint_stat) == -1) {
1802 if (dl + hdr.dirlist < dl)
1805 if (dl + hdr.dirlistlen < dl)
1807 dl += hdr.dirlistlen;
1808 if (dl > hint_stat.st_size)
1810 p = xmalloc(hdr.dirlistlen + 1);
1811 if (pread(fd, p, hdr.dirlistlen + 1,
1812 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 ||
1813 p[hdr.dirlistlen] != '\0') {
1822 * If caller agreed to receive list which includes the default
1823 * paths, we are done. Otherwise, if we still did not
1824 * calculated filtered result, do it now.
1827 return (hints[0] != '\0' ? hints : NULL);
1828 if (filtered_path != NULL)
1832 * Obtain the list of all configured search paths, and the
1833 * list of the default paths.
1835 * First estimate the size of the results.
1837 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1839 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1842 sargs.request = RTLD_DI_SERINFOSIZE;
1843 sargs.serinfo = &smeta;
1844 hargs.request = RTLD_DI_SERINFOSIZE;
1845 hargs.serinfo = &hmeta;
1847 path_enumerate(ld_standard_library_path, fill_search_info, &sargs);
1848 path_enumerate(hints, fill_search_info, &hargs);
1850 SLPinfo = xmalloc(smeta.dls_size);
1851 hintinfo = xmalloc(hmeta.dls_size);
1854 * Next fetch both sets of paths.
1856 sargs.request = RTLD_DI_SERINFO;
1857 sargs.serinfo = SLPinfo;
1858 sargs.serpath = &SLPinfo->dls_serpath[0];
1859 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1861 hargs.request = RTLD_DI_SERINFO;
1862 hargs.serinfo = hintinfo;
1863 hargs.serpath = &hintinfo->dls_serpath[0];
1864 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1866 path_enumerate(ld_standard_library_path, fill_search_info, &sargs);
1867 path_enumerate(hints, fill_search_info, &hargs);
1870 * Now calculate the difference between two sets, by excluding
1871 * standard paths from the full set.
1875 filtered_path = xmalloc(hdr.dirlistlen + 1);
1876 hintpath = &hintinfo->dls_serpath[0];
1877 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1879 SLPpath = &SLPinfo->dls_serpath[0];
1881 * Check each standard path against current.
1883 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1884 /* matched, skip the path */
1885 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1893 * Not matched against any standard path, add the path
1894 * to result. Separate consequtive paths with ':'.
1897 filtered_path[fndx] = ':';
1901 flen = strlen(hintpath->dls_name);
1902 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1905 filtered_path[fndx] = '\0';
1911 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1915 init_dag(Obj_Entry *root)
1917 const Needed_Entry *needed;
1918 const Objlist_Entry *elm;
1921 if (root->dag_inited)
1923 donelist_init(&donelist);
1925 /* Root object belongs to own DAG. */
1926 objlist_push_tail(&root->dldags, root);
1927 objlist_push_tail(&root->dagmembers, root);
1928 donelist_check(&donelist, root);
1931 * Add dependencies of root object to DAG in breadth order
1932 * by exploiting the fact that each new object get added
1933 * to the tail of the dagmembers list.
1935 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1936 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1937 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1939 objlist_push_tail(&needed->obj->dldags, root);
1940 objlist_push_tail(&root->dagmembers, needed->obj);
1943 root->dag_inited = true;
1947 init_marker(Obj_Entry *marker)
1950 bzero(marker, sizeof(*marker));
1951 marker->marker = true;
1955 globallist_curr(const Obj_Entry *obj)
1962 return (__DECONST(Obj_Entry *, obj));
1963 obj = TAILQ_PREV(obj, obj_entry_q, next);
1968 globallist_next(const Obj_Entry *obj)
1972 obj = TAILQ_NEXT(obj, next);
1976 return (__DECONST(Obj_Entry *, obj));
1980 /* Prevent the object from being unmapped while the bind lock is dropped. */
1982 hold_object(Obj_Entry *obj)
1989 unhold_object(Obj_Entry *obj)
1992 assert(obj->holdcount > 0);
1993 if (--obj->holdcount == 0 && obj->unholdfree)
1994 release_object(obj);
1998 process_z(Obj_Entry *root)
2000 const Objlist_Entry *elm;
2004 * Walk over object DAG and process every dependent object
2005 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2006 * to grow their own DAG.
2008 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2009 * symlook_global() to work.
2011 * For DF_1_NODELETE, the DAG should have its reference upped.
2013 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2017 if (obj->z_nodelete && !obj->ref_nodel) {
2018 dbg("obj %s -z nodelete", obj->path);
2021 obj->ref_nodel = true;
2023 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2024 dbg("obj %s -z global", obj->path);
2025 objlist_push_tail(&list_global, obj);
2031 * Initialize the dynamic linker. The argument is the address at which
2032 * the dynamic linker has been mapped into memory. The primary task of
2033 * this function is to relocate the dynamic linker.
2036 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2038 Obj_Entry objtmp; /* Temporary rtld object */
2039 const Elf_Ehdr *ehdr;
2040 const Elf_Dyn *dyn_rpath;
2041 const Elf_Dyn *dyn_soname;
2042 const Elf_Dyn *dyn_runpath;
2044 #ifdef RTLD_INIT_PAGESIZES_EARLY
2045 /* The page size is required by the dynamic memory allocator. */
2046 init_pagesizes(aux_info);
2050 * Conjure up an Obj_Entry structure for the dynamic linker.
2052 * The "path" member can't be initialized yet because string constants
2053 * cannot yet be accessed. Below we will set it correctly.
2055 memset(&objtmp, 0, sizeof(objtmp));
2058 objtmp.mapbase = mapbase;
2060 objtmp.relocbase = mapbase;
2063 objtmp.dynamic = rtld_dynamic(&objtmp);
2064 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2065 assert(objtmp.needed == NULL);
2066 #if !defined(__mips__)
2067 /* MIPS has a bogus DT_TEXTREL. */
2068 assert(!objtmp.textrel);
2071 * Temporarily put the dynamic linker entry into the object list, so
2072 * that symbols can be found.
2074 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2076 ehdr = (Elf_Ehdr *)mapbase;
2077 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2078 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]);
2080 /* Initialize the object list. */
2081 TAILQ_INIT(&obj_list);
2083 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2084 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2086 #ifndef RTLD_INIT_PAGESIZES_EARLY
2087 /* The page size is required by the dynamic memory allocator. */
2088 init_pagesizes(aux_info);
2091 if (aux_info[AT_OSRELDATE] != NULL)
2092 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2094 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2096 /* Replace the path with a dynamically allocated copy. */
2097 obj_rtld.path = xstrdup(ld_path_rtld);
2099 r_debug.r_brk = r_debug_state;
2100 r_debug.r_state = RT_CONSISTENT;
2104 * Retrieve the array of supported page sizes. The kernel provides the page
2105 * sizes in increasing order.
2108 init_pagesizes(Elf_Auxinfo **aux_info)
2110 static size_t psa[MAXPAGESIZES];
2114 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
2116 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2117 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2120 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2123 /* As a fallback, retrieve the base page size. */
2124 size = sizeof(psa[0]);
2125 if (aux_info[AT_PAGESZ] != NULL) {
2126 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2130 mib[1] = HW_PAGESIZE;
2134 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2135 _rtld_error("sysctl for hw.pagesize(s) failed");
2141 npagesizes = size / sizeof(pagesizes[0]);
2142 /* Discard any invalid entries at the end of the array. */
2143 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2148 * Add the init functions from a needed object list (and its recursive
2149 * needed objects) to "list". This is not used directly; it is a helper
2150 * function for initlist_add_objects(). The write lock must be held
2151 * when this function is called.
2154 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
2156 /* Recursively process the successor needed objects. */
2157 if (needed->next != NULL)
2158 initlist_add_neededs(needed->next, list);
2160 /* Process the current needed object. */
2161 if (needed->obj != NULL)
2162 initlist_add_objects(needed->obj, needed->obj, list);
2166 * Scan all of the DAGs rooted in the range of objects from "obj" to
2167 * "tail" and add their init functions to "list". This recurses over
2168 * the DAGs and ensure the proper init ordering such that each object's
2169 * needed libraries are initialized before the object itself. At the
2170 * same time, this function adds the objects to the global finalization
2171 * list "list_fini" in the opposite order. The write lock must be
2172 * held when this function is called.
2175 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2179 if (obj->init_scanned || obj->init_done)
2181 obj->init_scanned = true;
2183 /* Recursively process the successor objects. */
2184 nobj = globallist_next(obj);
2185 if (nobj != NULL && obj != tail)
2186 initlist_add_objects(nobj, tail, list);
2188 /* Recursively process the needed objects. */
2189 if (obj->needed != NULL)
2190 initlist_add_neededs(obj->needed, list);
2191 if (obj->needed_filtees != NULL)
2192 initlist_add_neededs(obj->needed_filtees, list);
2193 if (obj->needed_aux_filtees != NULL)
2194 initlist_add_neededs(obj->needed_aux_filtees, list);
2196 /* Add the object to the init list. */
2197 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
2198 obj->init_array != (Elf_Addr)NULL)
2199 objlist_push_tail(list, obj);
2201 /* Add the object to the global fini list in the reverse order. */
2202 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2203 && !obj->on_fini_list) {
2204 objlist_push_head(&list_fini, obj);
2205 obj->on_fini_list = true;
2210 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2214 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2216 Needed_Entry *needed, *needed1;
2218 for (needed = n; needed != NULL; needed = needed->next) {
2219 if (needed->obj != NULL) {
2220 dlclose_locked(needed->obj, lockstate);
2224 for (needed = n; needed != NULL; needed = needed1) {
2225 needed1 = needed->next;
2231 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2234 free_needed_filtees(obj->needed_filtees, lockstate);
2235 obj->needed_filtees = NULL;
2236 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2237 obj->needed_aux_filtees = NULL;
2238 obj->filtees_loaded = false;
2242 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2243 RtldLockState *lockstate)
2246 for (; needed != NULL; needed = needed->next) {
2247 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2248 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2249 RTLD_LOCAL, lockstate);
2254 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2257 lock_restart_for_upgrade(lockstate);
2258 if (!obj->filtees_loaded) {
2259 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2260 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2261 obj->filtees_loaded = true;
2266 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2270 for (; needed != NULL; needed = needed->next) {
2271 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2272 flags & ~RTLD_LO_NOLOAD);
2273 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2280 * Given a shared object, traverse its list of needed objects, and load
2281 * each of them. Returns 0 on success. Generates an error message and
2282 * returns -1 on failure.
2285 load_needed_objects(Obj_Entry *first, int flags)
2289 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2292 if (process_needed(obj, obj->needed, flags) == -1)
2299 load_preload_objects(void)
2301 char *p = ld_preload;
2303 static const char delim[] = " \t:;";
2308 p += strspn(p, delim);
2309 while (*p != '\0') {
2310 size_t len = strcspn(p, delim);
2315 obj = load_object(p, -1, NULL, 0);
2317 return -1; /* XXX - cleanup */
2318 obj->z_interpose = true;
2321 p += strspn(p, delim);
2323 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2328 printable_path(const char *path)
2331 return (path == NULL ? "<unknown>" : path);
2335 * Load a shared object into memory, if it is not already loaded. The
2336 * object may be specified by name or by user-supplied file descriptor
2337 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2340 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2344 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2353 TAILQ_FOREACH(obj, &obj_list, next) {
2354 if (obj->marker || obj->doomed)
2356 if (object_match_name(obj, name))
2360 path = find_library(name, refobj, &fd);
2368 * search_library_pathfds() opens a fresh file descriptor for the
2369 * library, so there is no need to dup().
2371 } else if (fd_u == -1) {
2373 * If we didn't find a match by pathname, or the name is not
2374 * supplied, open the file and check again by device and inode.
2375 * This avoids false mismatches caused by multiple links or ".."
2378 * To avoid a race, we open the file and use fstat() rather than
2381 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2382 _rtld_error("Cannot open \"%s\"", path);
2387 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2389 _rtld_error("Cannot dup fd");
2394 if (fstat(fd, &sb) == -1) {
2395 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2400 TAILQ_FOREACH(obj, &obj_list, next) {
2401 if (obj->marker || obj->doomed)
2403 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2406 if (obj != NULL && name != NULL) {
2407 object_add_name(obj, name);
2412 if (flags & RTLD_LO_NOLOAD) {
2418 /* First use of this object, so we must map it in */
2419 obj = do_load_object(fd, name, path, &sb, flags);
2428 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2435 * but first, make sure that environment variables haven't been
2436 * used to circumvent the noexec flag on a filesystem.
2438 if (dangerous_ld_env) {
2439 if (fstatfs(fd, &fs) != 0) {
2440 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2443 if (fs.f_flags & MNT_NOEXEC) {
2444 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2448 dbg("loading \"%s\"", printable_path(path));
2449 obj = map_object(fd, printable_path(path), sbp);
2454 * If DT_SONAME is present in the object, digest_dynamic2 already
2455 * added it to the object names.
2458 object_add_name(obj, name);
2460 digest_dynamic(obj, 0);
2461 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2462 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2463 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2465 dbg("refusing to load non-loadable \"%s\"", obj->path);
2466 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2467 munmap(obj->mapbase, obj->mapsize);
2472 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2473 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2476 linkmap_add(obj); /* for GDB & dlinfo() */
2477 max_stack_flags |= obj->stack_flags;
2479 dbg(" %p .. %p: %s", obj->mapbase,
2480 obj->mapbase + obj->mapsize - 1, obj->path);
2482 dbg(" WARNING: %s has impure text", obj->path);
2483 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2490 obj_from_addr(const void *addr)
2494 TAILQ_FOREACH(obj, &obj_list, next) {
2497 if (addr < (void *) obj->mapbase)
2499 if (addr < (void *) (obj->mapbase + obj->mapsize))
2508 Elf_Addr *preinit_addr;
2511 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2512 if (preinit_addr == NULL)
2515 for (index = 0; index < obj_main->preinit_array_num; index++) {
2516 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2517 dbg("calling preinit function for %s at %p", obj_main->path,
2518 (void *)preinit_addr[index]);
2519 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2520 0, 0, obj_main->path);
2521 call_init_pointer(obj_main, preinit_addr[index]);
2527 * Call the finalization functions for each of the objects in "list"
2528 * belonging to the DAG of "root" and referenced once. If NULL "root"
2529 * is specified, every finalization function will be called regardless
2530 * of the reference count and the list elements won't be freed. All of
2531 * the objects are expected to have non-NULL fini functions.
2534 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2538 Elf_Addr *fini_addr;
2541 assert(root == NULL || root->refcount == 1);
2544 root->doomed = true;
2547 * Preserve the current error message since a fini function might
2548 * call into the dynamic linker and overwrite it.
2550 saved_msg = errmsg_save();
2552 STAILQ_FOREACH(elm, list, link) {
2553 if (root != NULL && (elm->obj->refcount != 1 ||
2554 objlist_find(&root->dagmembers, elm->obj) == NULL))
2556 /* Remove object from fini list to prevent recursive invocation. */
2557 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2558 /* Ensure that new references cannot be acquired. */
2559 elm->obj->doomed = true;
2561 hold_object(elm->obj);
2562 lock_release(rtld_bind_lock, lockstate);
2564 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2565 * When this happens, DT_FINI_ARRAY is processed first.
2567 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2568 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2569 for (index = elm->obj->fini_array_num - 1; index >= 0;
2571 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2572 dbg("calling fini function for %s at %p",
2573 elm->obj->path, (void *)fini_addr[index]);
2574 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2575 (void *)fini_addr[index], 0, 0, elm->obj->path);
2576 call_initfini_pointer(elm->obj, fini_addr[index]);
2580 if (elm->obj->fini != (Elf_Addr)NULL) {
2581 dbg("calling fini function for %s at %p", elm->obj->path,
2582 (void *)elm->obj->fini);
2583 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2584 0, 0, elm->obj->path);
2585 call_initfini_pointer(elm->obj, elm->obj->fini);
2587 wlock_acquire(rtld_bind_lock, lockstate);
2588 unhold_object(elm->obj);
2589 /* No need to free anything if process is going down. */
2593 * We must restart the list traversal after every fini call
2594 * because a dlclose() call from the fini function or from
2595 * another thread might have modified the reference counts.
2599 } while (elm != NULL);
2600 errmsg_restore(saved_msg);
2604 * Call the initialization functions for each of the objects in
2605 * "list". All of the objects are expected to have non-NULL init
2609 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2614 Elf_Addr *init_addr;
2618 * Clean init_scanned flag so that objects can be rechecked and
2619 * possibly initialized earlier if any of vectors called below
2620 * cause the change by using dlopen.
2622 TAILQ_FOREACH(obj, &obj_list, next) {
2625 obj->init_scanned = false;
2629 * Preserve the current error message since an init function might
2630 * call into the dynamic linker and overwrite it.
2632 saved_msg = errmsg_save();
2633 STAILQ_FOREACH(elm, list, link) {
2634 if (elm->obj->init_done) /* Initialized early. */
2637 * Race: other thread might try to use this object before current
2638 * one completes the initialization. Not much can be done here
2639 * without better locking.
2641 elm->obj->init_done = true;
2642 hold_object(elm->obj);
2643 lock_release(rtld_bind_lock, lockstate);
2646 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2647 * When this happens, DT_INIT is processed first.
2649 if (elm->obj->init != (Elf_Addr)NULL) {
2650 dbg("calling init function for %s at %p", elm->obj->path,
2651 (void *)elm->obj->init);
2652 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2653 0, 0, elm->obj->path);
2654 call_initfini_pointer(elm->obj, elm->obj->init);
2656 init_addr = (Elf_Addr *)elm->obj->init_array;
2657 if (init_addr != NULL) {
2658 for (index = 0; index < elm->obj->init_array_num; index++) {
2659 if (init_addr[index] != 0 && init_addr[index] != 1) {
2660 dbg("calling init function for %s at %p", elm->obj->path,
2661 (void *)init_addr[index]);
2662 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2663 (void *)init_addr[index], 0, 0, elm->obj->path);
2664 call_init_pointer(elm->obj, init_addr[index]);
2668 wlock_acquire(rtld_bind_lock, lockstate);
2669 unhold_object(elm->obj);
2671 errmsg_restore(saved_msg);
2675 objlist_clear(Objlist *list)
2679 while (!STAILQ_EMPTY(list)) {
2680 elm = STAILQ_FIRST(list);
2681 STAILQ_REMOVE_HEAD(list, link);
2686 static Objlist_Entry *
2687 objlist_find(Objlist *list, const Obj_Entry *obj)
2691 STAILQ_FOREACH(elm, list, link)
2692 if (elm->obj == obj)
2698 objlist_init(Objlist *list)
2704 objlist_push_head(Objlist *list, Obj_Entry *obj)
2708 elm = NEW(Objlist_Entry);
2710 STAILQ_INSERT_HEAD(list, elm, link);
2714 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2718 elm = NEW(Objlist_Entry);
2720 STAILQ_INSERT_TAIL(list, elm, link);
2724 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2726 Objlist_Entry *elm, *listelm;
2728 STAILQ_FOREACH(listelm, list, link) {
2729 if (listelm->obj == listobj)
2732 elm = NEW(Objlist_Entry);
2734 if (listelm != NULL)
2735 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2737 STAILQ_INSERT_TAIL(list, elm, link);
2741 objlist_remove(Objlist *list, Obj_Entry *obj)
2745 if ((elm = objlist_find(list, obj)) != NULL) {
2746 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2752 * Relocate dag rooted in the specified object.
2753 * Returns 0 on success, or -1 on failure.
2757 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2758 int flags, RtldLockState *lockstate)
2764 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2765 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2774 * Prepare for, or clean after, relocating an object marked with
2775 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
2776 * segments are remapped read-write. After relocations are done, the
2777 * segment's permissions are returned back to the modes specified in
2778 * the phdrs. If any relocation happened, or always for wired
2779 * program, COW is triggered.
2782 reloc_textrel_prot(Obj_Entry *obj, bool before)
2789 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
2791 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
2793 base = obj->relocbase + trunc_page(ph->p_vaddr);
2794 sz = round_page(ph->p_vaddr + ph->p_filesz) -
2795 trunc_page(ph->p_vaddr);
2796 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0);
2797 if (mprotect(base, sz, prot) == -1) {
2798 _rtld_error("%s: Cannot write-%sable text segment: %s",
2799 obj->path, before ? "en" : "dis",
2800 rtld_strerror(errno));
2808 * Relocate single object.
2809 * Returns 0 on success, or -1 on failure.
2812 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2813 int flags, RtldLockState *lockstate)
2818 obj->relocated = true;
2820 dbg("relocating \"%s\"", obj->path);
2822 if (obj->symtab == NULL || obj->strtab == NULL ||
2823 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2824 _rtld_error("%s: Shared object has no run-time symbol table",
2829 /* There are relocations to the write-protected text segment. */
2830 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
2833 /* Process the non-PLT non-IFUNC relocations. */
2834 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2837 /* Re-protected the text segment. */
2838 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
2841 /* Set the special PLT or GOT entries. */
2844 /* Process the PLT relocations. */
2845 if (reloc_plt(obj) == -1)
2847 /* Relocate the jump slots if we are doing immediate binding. */
2848 if (obj->bind_now || bind_now)
2849 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2853 * Process the non-PLT IFUNC relocations. The relocations are
2854 * processed in two phases, because IFUNC resolvers may
2855 * reference other symbols, which must be readily processed
2856 * before resolvers are called.
2858 if (obj->non_plt_gnu_ifunc &&
2859 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
2862 if (!obj->mainprog && obj_enforce_relro(obj) == -1)
2866 * Set up the magic number and version in the Obj_Entry. These
2867 * were checked in the crt1.o from the original ElfKit, so we
2868 * set them for backward compatibility.
2870 obj->magic = RTLD_MAGIC;
2871 obj->version = RTLD_VERSION;
2877 * Relocate newly-loaded shared objects. The argument is a pointer to
2878 * the Obj_Entry for the first such object. All objects from the first
2879 * to the end of the list of objects are relocated. Returns 0 on success,
2883 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2884 int flags, RtldLockState *lockstate)
2889 for (error = 0, obj = first; obj != NULL;
2890 obj = TAILQ_NEXT(obj, next)) {
2893 error = relocate_object(obj, bind_now, rtldobj, flags,
2902 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2903 * referencing STT_GNU_IFUNC symbols is postponed till the other
2904 * relocations are done. The indirect functions specified as
2905 * ifunc are allowed to call other symbols, so we need to have
2906 * objects relocated before asking for resolution from indirects.
2908 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2909 * instead of the usual lazy handling of PLT slots. It is
2910 * consistent with how GNU does it.
2913 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2914 RtldLockState *lockstate)
2916 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2918 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2919 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2925 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2926 RtldLockState *lockstate)
2930 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2933 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2940 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2941 RtldLockState *lockstate)
2945 STAILQ_FOREACH(elm, list, link) {
2946 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2954 * Cleanup procedure. It will be called (by the atexit mechanism) just
2955 * before the process exits.
2960 RtldLockState lockstate;
2962 wlock_acquire(rtld_bind_lock, &lockstate);
2964 objlist_call_fini(&list_fini, NULL, &lockstate);
2965 /* No need to remove the items from the list, since we are exiting. */
2966 if (!libmap_disable)
2968 lock_release(rtld_bind_lock, &lockstate);
2972 * Iterate over a search path, translate each element, and invoke the
2973 * callback on the result.
2976 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2982 path += strspn(path, ":;");
2983 while (*path != '\0') {
2987 len = strcspn(path, ":;");
2988 trans = lm_findn(NULL, path, len);
2990 res = callback(trans, strlen(trans), arg);
2992 res = callback(path, len, arg);
2998 path += strspn(path, ":;");
3004 struct try_library_args {
3013 try_library_path(const char *dir, size_t dirlen, void *param)
3015 struct try_library_args *arg;
3019 if (*dir == '/' || trust) {
3022 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3025 pathname = arg->buffer;
3026 strncpy(pathname, dir, dirlen);
3027 pathname[dirlen] = '/';
3028 strcpy(pathname + dirlen + 1, arg->name);
3030 dbg(" Trying \"%s\"", pathname);
3031 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3033 dbg(" Opened \"%s\", fd %d", pathname, fd);
3034 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3035 strcpy(pathname, arg->buffer);
3039 dbg(" Failed to open \"%s\": %s",
3040 pathname, rtld_strerror(errno));
3047 search_library_path(const char *name, const char *path, int *fdp)
3050 struct try_library_args arg;
3056 arg.namelen = strlen(name);
3057 arg.buffer = xmalloc(PATH_MAX);
3058 arg.buflen = PATH_MAX;
3061 p = path_enumerate(path, try_library_path, &arg);
3071 * Finds the library with the given name using the directory descriptors
3072 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3074 * Returns a freshly-opened close-on-exec file descriptor for the library,
3075 * or -1 if the library cannot be found.
3078 search_library_pathfds(const char *name, const char *path, int *fdp)
3080 char *envcopy, *fdstr, *found, *last_token;
3084 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3086 /* Don't load from user-specified libdirs into setuid binaries. */
3090 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3094 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3095 if (name[0] == '/') {
3096 dbg("Absolute path (%s) passed to %s", name, __func__);
3101 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3102 * copy of the path, as strtok_r rewrites separator tokens
3106 envcopy = xstrdup(path);
3107 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3108 fdstr = strtok_r(NULL, ":", &last_token)) {
3109 dirfd = parse_integer(fdstr);
3111 _rtld_error("failed to parse directory FD: '%s'",
3115 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3118 len = strlen(fdstr) + strlen(name) + 3;
3119 found = xmalloc(len);
3120 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
3121 _rtld_error("error generating '%d/%s'",
3125 dbg("open('%s') => %d", found, fd);
3136 dlclose(void *handle)
3138 RtldLockState lockstate;
3141 wlock_acquire(rtld_bind_lock, &lockstate);
3142 error = dlclose_locked(handle, &lockstate);
3143 lock_release(rtld_bind_lock, &lockstate);
3148 dlclose_locked(void *handle, RtldLockState *lockstate)
3152 root = dlcheck(handle);
3155 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3158 /* Unreference the object and its dependencies. */
3159 root->dl_refcount--;
3161 if (root->refcount == 1) {
3163 * The object will be no longer referenced, so we must unload it.
3164 * First, call the fini functions.
3166 objlist_call_fini(&list_fini, root, lockstate);
3170 /* Finish cleaning up the newly-unreferenced objects. */
3171 GDB_STATE(RT_DELETE,&root->linkmap);
3172 unload_object(root, lockstate);
3173 GDB_STATE(RT_CONSISTENT,NULL);
3177 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3184 char *msg = error_message;
3185 error_message = NULL;
3190 * This function is deprecated and has no effect.
3193 dllockinit(void *context,
3194 void *(*lock_create)(void *context),
3195 void (*rlock_acquire)(void *lock),
3196 void (*wlock_acquire)(void *lock),
3197 void (*lock_release)(void *lock),
3198 void (*lock_destroy)(void *lock),
3199 void (*context_destroy)(void *context))
3201 static void *cur_context;
3202 static void (*cur_context_destroy)(void *);
3204 /* Just destroy the context from the previous call, if necessary. */
3205 if (cur_context_destroy != NULL)
3206 cur_context_destroy(cur_context);
3207 cur_context = context;
3208 cur_context_destroy = context_destroy;
3212 dlopen(const char *name, int mode)
3215 return (rtld_dlopen(name, -1, mode));
3219 fdlopen(int fd, int mode)
3222 return (rtld_dlopen(NULL, fd, mode));
3226 rtld_dlopen(const char *name, int fd, int mode)
3228 RtldLockState lockstate;
3231 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3232 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3233 if (ld_tracing != NULL) {
3234 rlock_acquire(rtld_bind_lock, &lockstate);
3235 if (sigsetjmp(lockstate.env, 0) != 0)
3236 lock_upgrade(rtld_bind_lock, &lockstate);
3237 environ = (char **)*get_program_var_addr("environ", &lockstate);
3238 lock_release(rtld_bind_lock, &lockstate);
3240 lo_flags = RTLD_LO_DLOPEN;
3241 if (mode & RTLD_NODELETE)
3242 lo_flags |= RTLD_LO_NODELETE;
3243 if (mode & RTLD_NOLOAD)
3244 lo_flags |= RTLD_LO_NOLOAD;
3245 if (ld_tracing != NULL)
3246 lo_flags |= RTLD_LO_TRACE;
3248 return (dlopen_object(name, fd, obj_main, lo_flags,
3249 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3253 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3258 if (obj->refcount == 0)
3259 unload_object(obj, lockstate);
3263 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3264 int mode, RtldLockState *lockstate)
3266 Obj_Entry *old_obj_tail;
3269 RtldLockState mlockstate;
3272 objlist_init(&initlist);
3274 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3275 wlock_acquire(rtld_bind_lock, &mlockstate);
3276 lockstate = &mlockstate;
3278 GDB_STATE(RT_ADD,NULL);
3280 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
3282 if (name == NULL && fd == -1) {
3286 obj = load_object(name, fd, refobj, lo_flags);
3291 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3292 objlist_push_tail(&list_global, obj);
3293 if (globallist_next(old_obj_tail) != NULL) {
3294 /* We loaded something new. */
3295 assert(globallist_next(old_obj_tail) == obj);
3296 result = load_needed_objects(obj,
3297 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
3301 result = rtld_verify_versions(&obj->dagmembers);
3302 if (result != -1 && ld_tracing)
3304 if (result == -1 || relocate_object_dag(obj,
3305 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3306 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3308 dlopen_cleanup(obj, lockstate);
3310 } else if (lo_flags & RTLD_LO_EARLY) {
3312 * Do not call the init functions for early loaded
3313 * filtees. The image is still not initialized enough
3316 * Our object is found by the global object list and
3317 * will be ordered among all init calls done right
3318 * before transferring control to main.
3321 /* Make list of init functions to call. */
3322 initlist_add_objects(obj, obj, &initlist);
3325 * Process all no_delete or global objects here, given
3326 * them own DAGs to prevent their dependencies from being
3327 * unloaded. This has to be done after we have loaded all
3328 * of the dependencies, so that we do not miss any.
3334 * Bump the reference counts for objects on this DAG. If
3335 * this is the first dlopen() call for the object that was
3336 * already loaded as a dependency, initialize the dag
3342 if ((lo_flags & RTLD_LO_TRACE) != 0)
3345 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3346 obj->z_nodelete) && !obj->ref_nodel) {
3347 dbg("obj %s nodelete", obj->path);
3349 obj->z_nodelete = obj->ref_nodel = true;
3353 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3355 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3357 if (!(lo_flags & RTLD_LO_EARLY)) {
3358 map_stacks_exec(lockstate);
3361 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3362 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3364 objlist_clear(&initlist);
3365 dlopen_cleanup(obj, lockstate);
3366 if (lockstate == &mlockstate)
3367 lock_release(rtld_bind_lock, lockstate);
3371 if (!(lo_flags & RTLD_LO_EARLY)) {
3372 /* Call the init functions. */
3373 objlist_call_init(&initlist, lockstate);
3375 objlist_clear(&initlist);
3376 if (lockstate == &mlockstate)
3377 lock_release(rtld_bind_lock, lockstate);
3380 trace_loaded_objects(obj);
3381 if (lockstate == &mlockstate)
3382 lock_release(rtld_bind_lock, lockstate);
3387 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3391 const Obj_Entry *obj, *defobj;
3394 RtldLockState lockstate;
3401 symlook_init(&req, name);
3403 req.flags = flags | SYMLOOK_IN_PLT;
3404 req.lockstate = &lockstate;
3406 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3407 rlock_acquire(rtld_bind_lock, &lockstate);
3408 if (sigsetjmp(lockstate.env, 0) != 0)
3409 lock_upgrade(rtld_bind_lock, &lockstate);
3410 if (handle == NULL || handle == RTLD_NEXT ||
3411 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3413 if ((obj = obj_from_addr(retaddr)) == NULL) {
3414 _rtld_error("Cannot determine caller's shared object");
3415 lock_release(rtld_bind_lock, &lockstate);
3416 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3419 if (handle == NULL) { /* Just the caller's shared object. */
3420 res = symlook_obj(&req, obj);
3423 defobj = req.defobj_out;
3425 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3426 handle == RTLD_SELF) { /* ... caller included */
3427 if (handle == RTLD_NEXT)
3428 obj = globallist_next(obj);
3429 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3432 res = symlook_obj(&req, obj);
3435 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3437 defobj = req.defobj_out;
3438 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3444 * Search the dynamic linker itself, and possibly resolve the
3445 * symbol from there. This is how the application links to
3446 * dynamic linker services such as dlopen.
3448 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3449 res = symlook_obj(&req, &obj_rtld);
3452 defobj = req.defobj_out;
3456 assert(handle == RTLD_DEFAULT);
3457 res = symlook_default(&req, obj);
3459 defobj = req.defobj_out;
3464 if ((obj = dlcheck(handle)) == NULL) {
3465 lock_release(rtld_bind_lock, &lockstate);
3466 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3470 donelist_init(&donelist);
3471 if (obj->mainprog) {
3472 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3473 res = symlook_global(&req, &donelist);
3476 defobj = req.defobj_out;
3479 * Search the dynamic linker itself, and possibly resolve the
3480 * symbol from there. This is how the application links to
3481 * dynamic linker services such as dlopen.
3483 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3484 res = symlook_obj(&req, &obj_rtld);
3487 defobj = req.defobj_out;
3492 /* Search the whole DAG rooted at the given object. */
3493 res = symlook_list(&req, &obj->dagmembers, &donelist);
3496 defobj = req.defobj_out;
3502 lock_release(rtld_bind_lock, &lockstate);
3505 * The value required by the caller is derived from the value
3506 * of the symbol. this is simply the relocated value of the
3509 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3510 sym = make_function_pointer(def, defobj);
3511 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3512 sym = rtld_resolve_ifunc(defobj, def);
3513 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3514 ti.ti_module = defobj->tlsindex;
3515 ti.ti_offset = def->st_value;
3516 sym = __tls_get_addr(&ti);
3518 sym = defobj->relocbase + def->st_value;
3519 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3523 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
3524 ve != NULL ? ve->name : "");
3525 lock_release(rtld_bind_lock, &lockstate);
3526 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3531 dlsym(void *handle, const char *name)
3533 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3538 dlfunc(void *handle, const char *name)
3545 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3551 dlvsym(void *handle, const char *name, const char *version)
3555 ventry.name = version;
3557 ventry.hash = elf_hash(version);
3559 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3564 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3566 const Obj_Entry *obj;
3567 RtldLockState lockstate;
3569 rlock_acquire(rtld_bind_lock, &lockstate);
3570 obj = obj_from_addr(addr);
3572 _rtld_error("No shared object contains address");
3573 lock_release(rtld_bind_lock, &lockstate);
3576 rtld_fill_dl_phdr_info(obj, phdr_info);
3577 lock_release(rtld_bind_lock, &lockstate);
3582 dladdr(const void *addr, Dl_info *info)
3584 const Obj_Entry *obj;
3587 unsigned long symoffset;
3588 RtldLockState lockstate;
3590 rlock_acquire(rtld_bind_lock, &lockstate);
3591 obj = obj_from_addr(addr);
3593 _rtld_error("No shared object contains address");
3594 lock_release(rtld_bind_lock, &lockstate);
3597 info->dli_fname = obj->path;
3598 info->dli_fbase = obj->mapbase;
3599 info->dli_saddr = (void *)0;
3600 info->dli_sname = NULL;
3603 * Walk the symbol list looking for the symbol whose address is
3604 * closest to the address sent in.
3606 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3607 def = obj->symtab + symoffset;
3610 * For skip the symbol if st_shndx is either SHN_UNDEF or
3613 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3617 * If the symbol is greater than the specified address, or if it
3618 * is further away from addr than the current nearest symbol,
3621 symbol_addr = obj->relocbase + def->st_value;
3622 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3625 /* Update our idea of the nearest symbol. */
3626 info->dli_sname = obj->strtab + def->st_name;
3627 info->dli_saddr = symbol_addr;
3630 if (info->dli_saddr == addr)
3633 lock_release(rtld_bind_lock, &lockstate);
3638 dlinfo(void *handle, int request, void *p)
3640 const Obj_Entry *obj;
3641 RtldLockState lockstate;
3644 rlock_acquire(rtld_bind_lock, &lockstate);
3646 if (handle == NULL || handle == RTLD_SELF) {
3649 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3650 if ((obj = obj_from_addr(retaddr)) == NULL)
3651 _rtld_error("Cannot determine caller's shared object");
3653 obj = dlcheck(handle);
3656 lock_release(rtld_bind_lock, &lockstate);
3662 case RTLD_DI_LINKMAP:
3663 *((struct link_map const **)p) = &obj->linkmap;
3665 case RTLD_DI_ORIGIN:
3666 error = rtld_dirname(obj->path, p);
3669 case RTLD_DI_SERINFOSIZE:
3670 case RTLD_DI_SERINFO:
3671 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3675 _rtld_error("Invalid request %d passed to dlinfo()", request);
3679 lock_release(rtld_bind_lock, &lockstate);
3685 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3688 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3689 phdr_info->dlpi_name = obj->path;
3690 phdr_info->dlpi_phdr = obj->phdr;
3691 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3692 phdr_info->dlpi_tls_modid = obj->tlsindex;
3693 phdr_info->dlpi_tls_data = obj->tlsinit;
3694 phdr_info->dlpi_adds = obj_loads;
3695 phdr_info->dlpi_subs = obj_loads - obj_count;
3699 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3701 struct dl_phdr_info phdr_info;
3702 Obj_Entry *obj, marker;
3703 RtldLockState bind_lockstate, phdr_lockstate;
3706 init_marker(&marker);
3709 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3710 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3711 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
3712 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
3713 rtld_fill_dl_phdr_info(obj, &phdr_info);
3715 lock_release(rtld_bind_lock, &bind_lockstate);
3717 error = callback(&phdr_info, sizeof phdr_info, param);
3719 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3721 obj = globallist_next(&marker);
3722 TAILQ_REMOVE(&obj_list, &marker, next);
3724 lock_release(rtld_bind_lock, &bind_lockstate);
3725 lock_release(rtld_phdr_lock, &phdr_lockstate);
3731 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3732 lock_release(rtld_bind_lock, &bind_lockstate);
3733 error = callback(&phdr_info, sizeof(phdr_info), param);
3735 lock_release(rtld_phdr_lock, &phdr_lockstate);
3740 fill_search_info(const char *dir, size_t dirlen, void *param)
3742 struct fill_search_info_args *arg;
3746 if (arg->request == RTLD_DI_SERINFOSIZE) {
3747 arg->serinfo->dls_cnt ++;
3748 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3750 struct dl_serpath *s_entry;
3752 s_entry = arg->serpath;
3753 s_entry->dls_name = arg->strspace;
3754 s_entry->dls_flags = arg->flags;
3756 strncpy(arg->strspace, dir, dirlen);
3757 arg->strspace[dirlen] = '\0';
3759 arg->strspace += dirlen + 1;
3767 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3769 struct dl_serinfo _info;
3770 struct fill_search_info_args args;
3772 args.request = RTLD_DI_SERINFOSIZE;
3773 args.serinfo = &_info;
3775 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3778 path_enumerate(obj->rpath, fill_search_info, &args);
3779 path_enumerate(ld_library_path, fill_search_info, &args);
3780 path_enumerate(obj->runpath, fill_search_info, &args);
3781 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3782 if (!obj->z_nodeflib)
3783 path_enumerate(ld_standard_library_path, fill_search_info, &args);
3786 if (request == RTLD_DI_SERINFOSIZE) {
3787 info->dls_size = _info.dls_size;
3788 info->dls_cnt = _info.dls_cnt;
3792 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3793 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3797 args.request = RTLD_DI_SERINFO;
3798 args.serinfo = info;
3799 args.serpath = &info->dls_serpath[0];
3800 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3802 args.flags = LA_SER_RUNPATH;
3803 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3806 args.flags = LA_SER_LIBPATH;
3807 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3810 args.flags = LA_SER_RUNPATH;
3811 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3814 args.flags = LA_SER_CONFIG;
3815 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3819 args.flags = LA_SER_DEFAULT;
3820 if (!obj->z_nodeflib &&
3821 path_enumerate(ld_standard_library_path, fill_search_info, &args) != NULL)
3827 rtld_dirname(const char *path, char *bname)
3831 /* Empty or NULL string gets treated as "." */
3832 if (path == NULL || *path == '\0') {
3838 /* Strip trailing slashes */
3839 endp = path + strlen(path) - 1;
3840 while (endp > path && *endp == '/')
3843 /* Find the start of the dir */
3844 while (endp > path && *endp != '/')
3847 /* Either the dir is "/" or there are no slashes */
3849 bname[0] = *endp == '/' ? '/' : '.';
3855 } while (endp > path && *endp == '/');
3858 if (endp - path + 2 > PATH_MAX)
3860 _rtld_error("Filename is too long: %s", path);
3864 strncpy(bname, path, endp - path + 1);
3865 bname[endp - path + 1] = '\0';
3870 rtld_dirname_abs(const char *path, char *base)
3874 if (realpath(path, base) == NULL)
3876 dbg("%s -> %s", path, base);
3877 last = strrchr(base, '/');
3886 linkmap_add(Obj_Entry *obj)
3888 struct link_map *l = &obj->linkmap;
3889 struct link_map *prev;
3891 obj->linkmap.l_name = obj->path;
3892 obj->linkmap.l_addr = obj->mapbase;
3893 obj->linkmap.l_ld = obj->dynamic;
3895 /* GDB needs load offset on MIPS to use the symbols */
3896 obj->linkmap.l_offs = obj->relocbase;
3899 if (r_debug.r_map == NULL) {
3905 * Scan to the end of the list, but not past the entry for the
3906 * dynamic linker, which we want to keep at the very end.
3908 for (prev = r_debug.r_map;
3909 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3910 prev = prev->l_next)
3913 /* Link in the new entry. */
3915 l->l_next = prev->l_next;
3916 if (l->l_next != NULL)
3917 l->l_next->l_prev = l;
3922 linkmap_delete(Obj_Entry *obj)
3924 struct link_map *l = &obj->linkmap;
3926 if (l->l_prev == NULL) {
3927 if ((r_debug.r_map = l->l_next) != NULL)
3928 l->l_next->l_prev = NULL;
3932 if ((l->l_prev->l_next = l->l_next) != NULL)
3933 l->l_next->l_prev = l->l_prev;
3937 * Function for the debugger to set a breakpoint on to gain control.
3939 * The two parameters allow the debugger to easily find and determine
3940 * what the runtime loader is doing and to whom it is doing it.
3942 * When the loadhook trap is hit (r_debug_state, set at program
3943 * initialization), the arguments can be found on the stack:
3945 * +8 struct link_map *m
3946 * +4 struct r_debug *rd
3950 r_debug_state(struct r_debug* rd, struct link_map *m)
3953 * The following is a hack to force the compiler to emit calls to
3954 * this function, even when optimizing. If the function is empty,
3955 * the compiler is not obliged to emit any code for calls to it,
3956 * even when marked __noinline. However, gdb depends on those
3959 __compiler_membar();
3963 * A function called after init routines have completed. This can be used to
3964 * break before a program's entry routine is called, and can be used when
3965 * main is not available in the symbol table.
3968 _r_debug_postinit(struct link_map *m)
3971 /* See r_debug_state(). */
3972 __compiler_membar();
3976 release_object(Obj_Entry *obj)
3979 if (obj->holdcount > 0) {
3980 obj->unholdfree = true;
3983 munmap(obj->mapbase, obj->mapsize);
3984 linkmap_delete(obj);
3989 * Get address of the pointer variable in the main program.
3990 * Prefer non-weak symbol over the weak one.
3992 static const void **
3993 get_program_var_addr(const char *name, RtldLockState *lockstate)
3998 symlook_init(&req, name);
3999 req.lockstate = lockstate;
4000 donelist_init(&donelist);
4001 if (symlook_global(&req, &donelist) != 0)
4003 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4004 return ((const void **)make_function_pointer(req.sym_out,
4006 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4007 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
4009 return ((const void **)(req.defobj_out->relocbase +
4010 req.sym_out->st_value));
4014 * Set a pointer variable in the main program to the given value. This
4015 * is used to set key variables such as "environ" before any of the
4016 * init functions are called.
4019 set_program_var(const char *name, const void *value)
4023 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4024 dbg("\"%s\": *%p <-- %p", name, addr, value);
4030 * Search the global objects, including dependencies and main object,
4031 * for the given symbol.
4034 symlook_global(SymLook *req, DoneList *donelist)
4037 const Objlist_Entry *elm;
4040 symlook_init_from_req(&req1, req);
4042 /* Search all objects loaded at program start up. */
4043 if (req->defobj_out == NULL ||
4044 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4045 res = symlook_list(&req1, &list_main, donelist);
4046 if (res == 0 && (req->defobj_out == NULL ||
4047 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4048 req->sym_out = req1.sym_out;
4049 req->defobj_out = req1.defobj_out;
4050 assert(req->defobj_out != NULL);
4054 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4055 STAILQ_FOREACH(elm, &list_global, link) {
4056 if (req->defobj_out != NULL &&
4057 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4059 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4060 if (res == 0 && (req->defobj_out == NULL ||
4061 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4062 req->sym_out = req1.sym_out;
4063 req->defobj_out = req1.defobj_out;
4064 assert(req->defobj_out != NULL);
4068 return (req->sym_out != NULL ? 0 : ESRCH);
4072 * Given a symbol name in a referencing object, find the corresponding
4073 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4074 * no definition was found. Returns a pointer to the Obj_Entry of the
4075 * defining object via the reference parameter DEFOBJ_OUT.
4078 symlook_default(SymLook *req, const Obj_Entry *refobj)
4081 const Objlist_Entry *elm;
4085 donelist_init(&donelist);
4086 symlook_init_from_req(&req1, req);
4089 * Look first in the referencing object if linked symbolically,
4090 * and similarly handle protected symbols.
4092 res = symlook_obj(&req1, refobj);
4093 if (res == 0 && (refobj->symbolic ||
4094 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) {
4095 req->sym_out = req1.sym_out;
4096 req->defobj_out = req1.defobj_out;
4097 assert(req->defobj_out != NULL);
4099 if (refobj->symbolic || req->defobj_out != NULL)
4100 donelist_check(&donelist, refobj);
4102 symlook_global(req, &donelist);
4104 /* Search all dlopened DAGs containing the referencing object. */
4105 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4106 if (req->sym_out != NULL &&
4107 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4109 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4110 if (res == 0 && (req->sym_out == NULL ||
4111 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4112 req->sym_out = req1.sym_out;
4113 req->defobj_out = req1.defobj_out;
4114 assert(req->defobj_out != NULL);
4119 * Search the dynamic linker itself, and possibly resolve the
4120 * symbol from there. This is how the application links to
4121 * dynamic linker services such as dlopen.
4123 if (req->sym_out == NULL ||
4124 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4125 res = symlook_obj(&req1, &obj_rtld);
4127 req->sym_out = req1.sym_out;
4128 req->defobj_out = req1.defobj_out;
4129 assert(req->defobj_out != NULL);
4133 return (req->sym_out != NULL ? 0 : ESRCH);
4137 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4140 const Obj_Entry *defobj;
4141 const Objlist_Entry *elm;
4147 STAILQ_FOREACH(elm, objlist, link) {
4148 if (donelist_check(dlp, elm->obj))
4150 symlook_init_from_req(&req1, req);
4151 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4152 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4154 defobj = req1.defobj_out;
4155 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4162 req->defobj_out = defobj;
4169 * Search the chain of DAGS cointed to by the given Needed_Entry
4170 * for a symbol of the given name. Each DAG is scanned completely
4171 * before advancing to the next one. Returns a pointer to the symbol,
4172 * or NULL if no definition was found.
4175 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4178 const Needed_Entry *n;
4179 const Obj_Entry *defobj;
4185 symlook_init_from_req(&req1, req);
4186 for (n = needed; n != NULL; n = n->next) {
4187 if (n->obj == NULL ||
4188 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
4190 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4192 defobj = req1.defobj_out;
4193 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4199 req->defobj_out = defobj;
4206 * Search the symbol table of a single shared object for a symbol of
4207 * the given name and version, if requested. Returns a pointer to the
4208 * symbol, or NULL if no definition was found. If the object is
4209 * filter, return filtered symbol from filtee.
4211 * The symbol's hash value is passed in for efficiency reasons; that
4212 * eliminates many recomputations of the hash value.
4215 symlook_obj(SymLook *req, const Obj_Entry *obj)
4219 int flags, res, mres;
4222 * If there is at least one valid hash at this point, we prefer to
4223 * use the faster GNU version if available.
4225 if (obj->valid_hash_gnu)
4226 mres = symlook_obj1_gnu(req, obj);
4227 else if (obj->valid_hash_sysv)
4228 mres = symlook_obj1_sysv(req, obj);
4233 if (obj->needed_filtees != NULL) {
4234 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4235 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4236 donelist_init(&donelist);
4237 symlook_init_from_req(&req1, req);
4238 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
4240 req->sym_out = req1.sym_out;
4241 req->defobj_out = req1.defobj_out;
4245 if (obj->needed_aux_filtees != NULL) {
4246 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4247 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4248 donelist_init(&donelist);
4249 symlook_init_from_req(&req1, req);
4250 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
4252 req->sym_out = req1.sym_out;
4253 req->defobj_out = req1.defobj_out;
4261 /* Symbol match routine common to both hash functions */
4263 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4264 const unsigned long symnum)
4267 const Elf_Sym *symp;
4270 symp = obj->symtab + symnum;
4271 strp = obj->strtab + symp->st_name;
4273 switch (ELF_ST_TYPE(symp->st_info)) {
4279 if (symp->st_value == 0)
4283 if (symp->st_shndx != SHN_UNDEF)
4286 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4287 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4294 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4297 if (req->ventry == NULL) {
4298 if (obj->versyms != NULL) {
4299 verndx = VER_NDX(obj->versyms[symnum]);
4300 if (verndx > obj->vernum) {
4302 "%s: symbol %s references wrong version %d",
4303 obj->path, obj->strtab + symnum, verndx);
4307 * If we are not called from dlsym (i.e. this
4308 * is a normal relocation from unversioned
4309 * binary), accept the symbol immediately if
4310 * it happens to have first version after this
4311 * shared object became versioned. Otherwise,
4312 * if symbol is versioned and not hidden,
4313 * remember it. If it is the only symbol with
4314 * this name exported by the shared object, it
4315 * will be returned as a match by the calling
4316 * function. If symbol is global (verndx < 2)
4317 * accept it unconditionally.
4319 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4320 verndx == VER_NDX_GIVEN) {
4321 result->sym_out = symp;
4324 else if (verndx >= VER_NDX_GIVEN) {
4325 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4327 if (result->vsymp == NULL)
4328 result->vsymp = symp;
4334 result->sym_out = symp;
4337 if (obj->versyms == NULL) {
4338 if (object_match_name(obj, req->ventry->name)) {
4339 _rtld_error("%s: object %s should provide version %s "
4340 "for symbol %s", obj_rtld.path, obj->path,
4341 req->ventry->name, obj->strtab + symnum);
4345 verndx = VER_NDX(obj->versyms[symnum]);
4346 if (verndx > obj->vernum) {
4347 _rtld_error("%s: symbol %s references wrong version %d",
4348 obj->path, obj->strtab + symnum, verndx);
4351 if (obj->vertab[verndx].hash != req->ventry->hash ||
4352 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4354 * Version does not match. Look if this is a
4355 * global symbol and if it is not hidden. If
4356 * global symbol (verndx < 2) is available,
4357 * use it. Do not return symbol if we are
4358 * called by dlvsym, because dlvsym looks for
4359 * a specific version and default one is not
4360 * what dlvsym wants.
4362 if ((req->flags & SYMLOOK_DLSYM) ||
4363 (verndx >= VER_NDX_GIVEN) ||
4364 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4368 result->sym_out = symp;
4373 * Search for symbol using SysV hash function.
4374 * obj->buckets is known not to be NULL at this point; the test for this was
4375 * performed with the obj->valid_hash_sysv assignment.
4378 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4380 unsigned long symnum;
4381 Sym_Match_Result matchres;
4383 matchres.sym_out = NULL;
4384 matchres.vsymp = NULL;
4385 matchres.vcount = 0;
4387 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4388 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4389 if (symnum >= obj->nchains)
4390 return (ESRCH); /* Bad object */
4392 if (matched_symbol(req, obj, &matchres, symnum)) {
4393 req->sym_out = matchres.sym_out;
4394 req->defobj_out = obj;
4398 if (matchres.vcount == 1) {
4399 req->sym_out = matchres.vsymp;
4400 req->defobj_out = obj;
4406 /* Search for symbol using GNU hash function */
4408 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4410 Elf_Addr bloom_word;
4411 const Elf32_Word *hashval;
4413 Sym_Match_Result matchres;
4414 unsigned int h1, h2;
4415 unsigned long symnum;
4417 matchres.sym_out = NULL;
4418 matchres.vsymp = NULL;
4419 matchres.vcount = 0;
4421 /* Pick right bitmask word from Bloom filter array */
4422 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4423 obj->maskwords_bm_gnu];
4425 /* Calculate modulus word size of gnu hash and its derivative */
4426 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4427 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4429 /* Filter out the "definitely not in set" queries */
4430 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4433 /* Locate hash chain and corresponding value element*/
4434 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4437 hashval = &obj->chain_zero_gnu[bucket];
4439 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4440 symnum = hashval - obj->chain_zero_gnu;
4441 if (matched_symbol(req, obj, &matchres, symnum)) {
4442 req->sym_out = matchres.sym_out;
4443 req->defobj_out = obj;
4447 } while ((*hashval++ & 1) == 0);
4448 if (matchres.vcount == 1) {
4449 req->sym_out = matchres.vsymp;
4450 req->defobj_out = obj;
4457 trace_loaded_objects(Obj_Entry *obj)
4459 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4462 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL)
4465 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL)
4466 fmt1 = "\t%o => %p (%x)\n";
4468 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL)
4469 fmt2 = "\t%o (%x)\n";
4471 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL"));
4473 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4474 Needed_Entry *needed;
4480 if (list_containers && obj->needed != NULL)
4481 rtld_printf("%s:\n", obj->path);
4482 for (needed = obj->needed; needed; needed = needed->next) {
4483 if (needed->obj != NULL) {
4484 if (needed->obj->traced && !list_containers)
4486 needed->obj->traced = true;
4487 path = needed->obj->path;
4491 name = (char *)obj->strtab + needed->name;
4492 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4494 fmt = is_lib ? fmt1 : fmt2;
4495 while ((c = *fmt++) != '\0') {
4521 rtld_putstr(main_local);
4524 rtld_putstr(obj_main->path);
4531 rtld_printf("%d", sodp->sod_major);
4534 rtld_printf("%d", sodp->sod_minor);
4541 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4554 * Unload a dlopened object and its dependencies from memory and from
4555 * our data structures. It is assumed that the DAG rooted in the
4556 * object has already been unreferenced, and that the object has a
4557 * reference count of 0.
4560 unload_object(Obj_Entry *root, RtldLockState *lockstate)
4562 Obj_Entry marker, *obj, *next;
4564 assert(root->refcount == 0);
4567 * Pass over the DAG removing unreferenced objects from
4568 * appropriate lists.
4570 unlink_object(root);
4572 /* Unmap all objects that are no longer referenced. */
4573 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
4574 next = TAILQ_NEXT(obj, next);
4575 if (obj->marker || obj->refcount != 0)
4577 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
4578 obj->mapsize, 0, obj->path);
4579 dbg("unloading \"%s\"", obj->path);
4581 * Unlink the object now to prevent new references from
4582 * being acquired while the bind lock is dropped in
4583 * recursive dlclose() invocations.
4585 TAILQ_REMOVE(&obj_list, obj, next);
4588 if (obj->filtees_loaded) {
4590 init_marker(&marker);
4591 TAILQ_INSERT_BEFORE(next, &marker, next);
4592 unload_filtees(obj, lockstate);
4593 next = TAILQ_NEXT(&marker, next);
4594 TAILQ_REMOVE(&obj_list, &marker, next);
4596 unload_filtees(obj, lockstate);
4598 release_object(obj);
4603 unlink_object(Obj_Entry *root)
4607 if (root->refcount == 0) {
4608 /* Remove the object from the RTLD_GLOBAL list. */
4609 objlist_remove(&list_global, root);
4611 /* Remove the object from all objects' DAG lists. */
4612 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4613 objlist_remove(&elm->obj->dldags, root);
4614 if (elm->obj != root)
4615 unlink_object(elm->obj);
4621 ref_dag(Obj_Entry *root)
4625 assert(root->dag_inited);
4626 STAILQ_FOREACH(elm, &root->dagmembers, link)
4627 elm->obj->refcount++;
4631 unref_dag(Obj_Entry *root)
4635 assert(root->dag_inited);
4636 STAILQ_FOREACH(elm, &root->dagmembers, link)
4637 elm->obj->refcount--;
4641 * Common code for MD __tls_get_addr().
4643 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4645 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4647 Elf_Addr *newdtv, *dtv;
4648 RtldLockState lockstate;
4652 /* Check dtv generation in case new modules have arrived */
4653 if (dtv[0] != tls_dtv_generation) {
4654 wlock_acquire(rtld_bind_lock, &lockstate);
4655 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4657 if (to_copy > tls_max_index)
4658 to_copy = tls_max_index;
4659 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4660 newdtv[0] = tls_dtv_generation;
4661 newdtv[1] = tls_max_index;
4663 lock_release(rtld_bind_lock, &lockstate);
4664 dtv = *dtvp = newdtv;
4667 /* Dynamically allocate module TLS if necessary */
4668 if (dtv[index + 1] == 0) {
4669 /* Signal safe, wlock will block out signals. */
4670 wlock_acquire(rtld_bind_lock, &lockstate);
4671 if (!dtv[index + 1])
4672 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4673 lock_release(rtld_bind_lock, &lockstate);
4675 return ((void *)(dtv[index + 1] + offset));
4679 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4684 /* Check dtv generation in case new modules have arrived */
4685 if (__predict_true(dtv[0] == tls_dtv_generation &&
4686 dtv[index + 1] != 0))
4687 return ((void *)(dtv[index + 1] + offset));
4688 return (tls_get_addr_slow(dtvp, index, offset));
4691 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
4692 defined(__powerpc__) || defined(__riscv)
4695 * Allocate Static TLS using the Variant I method.
4698 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4707 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4710 assert(tcbsize >= TLS_TCB_SIZE);
4711 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4712 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4714 if (oldtcb != NULL) {
4715 memcpy(tls, oldtcb, tls_static_space);
4718 /* Adjust the DTV. */
4720 for (i = 0; i < dtv[1]; i++) {
4721 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4722 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4723 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4727 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4729 dtv[0] = tls_dtv_generation;
4730 dtv[1] = tls_max_index;
4732 for (obj = globallist_curr(objs); obj != NULL;
4733 obj = globallist_next(obj)) {
4734 if (obj->tlsoffset > 0) {
4735 addr = (Elf_Addr)tls + obj->tlsoffset;
4736 if (obj->tlsinitsize > 0)
4737 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4738 if (obj->tlssize > obj->tlsinitsize)
4739 memset((void*) (addr + obj->tlsinitsize), 0,
4740 obj->tlssize - obj->tlsinitsize);
4741 dtv[obj->tlsindex + 1] = addr;
4750 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4753 Elf_Addr tlsstart, tlsend;
4756 assert(tcbsize >= TLS_TCB_SIZE);
4758 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4759 tlsend = tlsstart + tls_static_space;
4761 dtv = *(Elf_Addr **)tlsstart;
4763 for (i = 0; i < dtvsize; i++) {
4764 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4765 free((void*)dtv[i+2]);
4774 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4777 * Allocate Static TLS using the Variant II method.
4780 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4783 size_t size, ralign;
4785 Elf_Addr *dtv, *olddtv;
4786 Elf_Addr segbase, oldsegbase, addr;
4790 if (tls_static_max_align > ralign)
4791 ralign = tls_static_max_align;
4792 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4794 assert(tcbsize >= 2*sizeof(Elf_Addr));
4795 tls = malloc_aligned(size, ralign);
4796 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4798 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4799 ((Elf_Addr*)segbase)[0] = segbase;
4800 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4802 dtv[0] = tls_dtv_generation;
4803 dtv[1] = tls_max_index;
4807 * Copy the static TLS block over whole.
4809 oldsegbase = (Elf_Addr) oldtls;
4810 memcpy((void *)(segbase - tls_static_space),
4811 (const void *)(oldsegbase - tls_static_space),
4815 * If any dynamic TLS blocks have been created tls_get_addr(),
4818 olddtv = ((Elf_Addr**)oldsegbase)[1];
4819 for (i = 0; i < olddtv[1]; i++) {
4820 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4821 dtv[i+2] = olddtv[i+2];
4827 * We assume that this block was the one we created with
4828 * allocate_initial_tls().
4830 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4832 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4833 if (obj->marker || obj->tlsoffset == 0)
4835 addr = segbase - obj->tlsoffset;
4836 memset((void*) (addr + obj->tlsinitsize),
4837 0, obj->tlssize - obj->tlsinitsize);
4839 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4840 dtv[obj->tlsindex + 1] = addr;
4844 return (void*) segbase;
4848 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4851 size_t size, ralign;
4853 Elf_Addr tlsstart, tlsend;
4856 * Figure out the size of the initial TLS block so that we can
4857 * find stuff which ___tls_get_addr() allocated dynamically.
4860 if (tls_static_max_align > ralign)
4861 ralign = tls_static_max_align;
4862 size = round(tls_static_space, ralign);
4864 dtv = ((Elf_Addr**)tls)[1];
4866 tlsend = (Elf_Addr) tls;
4867 tlsstart = tlsend - size;
4868 for (i = 0; i < dtvsize; i++) {
4869 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4870 free_aligned((void *)dtv[i + 2]);
4874 free_aligned((void *)tlsstart);
4881 * Allocate TLS block for module with given index.
4884 allocate_module_tls(int index)
4889 TAILQ_FOREACH(obj, &obj_list, next) {
4892 if (obj->tlsindex == index)
4896 _rtld_error("Can't find module with TLS index %d", index);
4900 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4901 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4902 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4908 allocate_tls_offset(Obj_Entry *obj)
4915 if (obj->tlssize == 0) {
4916 obj->tls_done = true;
4920 if (tls_last_offset == 0)
4921 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4923 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4924 obj->tlssize, obj->tlsalign);
4927 * If we have already fixed the size of the static TLS block, we
4928 * must stay within that size. When allocating the static TLS, we
4929 * leave a small amount of space spare to be used for dynamically
4930 * loading modules which use static TLS.
4932 if (tls_static_space != 0) {
4933 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4935 } else if (obj->tlsalign > tls_static_max_align) {
4936 tls_static_max_align = obj->tlsalign;
4939 tls_last_offset = obj->tlsoffset = off;
4940 tls_last_size = obj->tlssize;
4941 obj->tls_done = true;
4947 free_tls_offset(Obj_Entry *obj)
4951 * If we were the last thing to allocate out of the static TLS
4952 * block, we give our space back to the 'allocator'. This is a
4953 * simplistic workaround to allow libGL.so.1 to be loaded and
4954 * unloaded multiple times.
4956 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4957 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4958 tls_last_offset -= obj->tlssize;
4964 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4967 RtldLockState lockstate;
4969 wlock_acquire(rtld_bind_lock, &lockstate);
4970 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
4972 lock_release(rtld_bind_lock, &lockstate);
4977 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4979 RtldLockState lockstate;
4981 wlock_acquire(rtld_bind_lock, &lockstate);
4982 free_tls(tcb, tcbsize, tcbalign);
4983 lock_release(rtld_bind_lock, &lockstate);
4987 object_add_name(Obj_Entry *obj, const char *name)
4993 entry = malloc(sizeof(Name_Entry) + len);
4995 if (entry != NULL) {
4996 strcpy(entry->name, name);
4997 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5002 object_match_name(const Obj_Entry *obj, const char *name)
5006 STAILQ_FOREACH(entry, &obj->names, link) {
5007 if (strcmp(name, entry->name) == 0)
5014 locate_dependency(const Obj_Entry *obj, const char *name)
5016 const Objlist_Entry *entry;
5017 const Needed_Entry *needed;
5019 STAILQ_FOREACH(entry, &list_main, link) {
5020 if (object_match_name(entry->obj, name))
5024 for (needed = obj->needed; needed != NULL; needed = needed->next) {
5025 if (strcmp(obj->strtab + needed->name, name) == 0 ||
5026 (needed->obj != NULL && object_match_name(needed->obj, name))) {
5028 * If there is DT_NEEDED for the name we are looking for,
5029 * we are all set. Note that object might not be found if
5030 * dependency was not loaded yet, so the function can
5031 * return NULL here. This is expected and handled
5032 * properly by the caller.
5034 return (needed->obj);
5037 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
5043 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
5044 const Elf_Vernaux *vna)
5046 const Elf_Verdef *vd;
5047 const char *vername;
5049 vername = refobj->strtab + vna->vna_name;
5050 vd = depobj->verdef;
5052 _rtld_error("%s: version %s required by %s not defined",
5053 depobj->path, vername, refobj->path);
5057 if (vd->vd_version != VER_DEF_CURRENT) {
5058 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5059 depobj->path, vd->vd_version);
5062 if (vna->vna_hash == vd->vd_hash) {
5063 const Elf_Verdaux *aux = (const Elf_Verdaux *)
5064 ((char *)vd + vd->vd_aux);
5065 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
5068 if (vd->vd_next == 0)
5070 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
5072 if (vna->vna_flags & VER_FLG_WEAK)
5074 _rtld_error("%s: version %s required by %s not found",
5075 depobj->path, vername, refobj->path);
5080 rtld_verify_object_versions(Obj_Entry *obj)
5082 const Elf_Verneed *vn;
5083 const Elf_Verdef *vd;
5084 const Elf_Verdaux *vda;
5085 const Elf_Vernaux *vna;
5086 const Obj_Entry *depobj;
5087 int maxvernum, vernum;
5089 if (obj->ver_checked)
5091 obj->ver_checked = true;
5095 * Walk over defined and required version records and figure out
5096 * max index used by any of them. Do very basic sanity checking
5100 while (vn != NULL) {
5101 if (vn->vn_version != VER_NEED_CURRENT) {
5102 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
5103 obj->path, vn->vn_version);
5106 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
5108 vernum = VER_NEED_IDX(vna->vna_other);
5109 if (vernum > maxvernum)
5111 if (vna->vna_next == 0)
5113 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
5115 if (vn->vn_next == 0)
5117 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
5121 while (vd != NULL) {
5122 if (vd->vd_version != VER_DEF_CURRENT) {
5123 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5124 obj->path, vd->vd_version);
5127 vernum = VER_DEF_IDX(vd->vd_ndx);
5128 if (vernum > maxvernum)
5130 if (vd->vd_next == 0)
5132 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
5139 * Store version information in array indexable by version index.
5140 * Verify that object version requirements are satisfied along the
5143 obj->vernum = maxvernum + 1;
5144 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
5147 while (vd != NULL) {
5148 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
5149 vernum = VER_DEF_IDX(vd->vd_ndx);
5150 assert(vernum <= maxvernum);
5151 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
5152 obj->vertab[vernum].hash = vd->vd_hash;
5153 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
5154 obj->vertab[vernum].file = NULL;
5155 obj->vertab[vernum].flags = 0;
5157 if (vd->vd_next == 0)
5159 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
5163 while (vn != NULL) {
5164 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
5167 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
5169 if (check_object_provided_version(obj, depobj, vna))
5171 vernum = VER_NEED_IDX(vna->vna_other);
5172 assert(vernum <= maxvernum);
5173 obj->vertab[vernum].hash = vna->vna_hash;
5174 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
5175 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
5176 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
5177 VER_INFO_HIDDEN : 0;
5178 if (vna->vna_next == 0)
5180 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
5182 if (vn->vn_next == 0)
5184 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
5190 rtld_verify_versions(const Objlist *objlist)
5192 Objlist_Entry *entry;
5196 STAILQ_FOREACH(entry, objlist, link) {
5198 * Skip dummy objects or objects that have their version requirements
5201 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
5203 if (rtld_verify_object_versions(entry->obj) == -1) {
5205 if (ld_tracing == NULL)
5209 if (rc == 0 || ld_tracing != NULL)
5210 rc = rtld_verify_object_versions(&obj_rtld);
5215 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
5220 vernum = VER_NDX(obj->versyms[symnum]);
5221 if (vernum >= obj->vernum) {
5222 _rtld_error("%s: symbol %s has wrong verneed value %d",
5223 obj->path, obj->strtab + symnum, vernum);
5224 } else if (obj->vertab[vernum].hash != 0) {
5225 return &obj->vertab[vernum];
5232 _rtld_get_stack_prot(void)
5235 return (stack_prot);
5239 _rtld_is_dlopened(void *arg)
5242 RtldLockState lockstate;
5245 rlock_acquire(rtld_bind_lock, &lockstate);
5248 obj = obj_from_addr(arg);
5250 _rtld_error("No shared object contains address");
5251 lock_release(rtld_bind_lock, &lockstate);
5254 res = obj->dlopened ? 1 : 0;
5255 lock_release(rtld_bind_lock, &lockstate);
5260 obj_enforce_relro(Obj_Entry *obj)
5263 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size,
5265 _rtld_error("%s: Cannot enforce relro protection: %s",
5266 obj->path, rtld_strerror(errno));
5273 map_stacks_exec(RtldLockState *lockstate)
5275 void (*thr_map_stacks_exec)(void);
5277 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
5279 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
5280 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
5281 if (thr_map_stacks_exec != NULL) {
5282 stack_prot |= PROT_EXEC;
5283 thr_map_stacks_exec();
5288 symlook_init(SymLook *dst, const char *name)
5291 bzero(dst, sizeof(*dst));
5293 dst->hash = elf_hash(name);
5294 dst->hash_gnu = gnu_hash(name);
5298 symlook_init_from_req(SymLook *dst, const SymLook *src)
5301 dst->name = src->name;
5302 dst->hash = src->hash;
5303 dst->hash_gnu = src->hash_gnu;
5304 dst->ventry = src->ventry;
5305 dst->flags = src->flags;
5306 dst->defobj_out = NULL;
5307 dst->sym_out = NULL;
5308 dst->lockstate = src->lockstate;
5312 open_binary_fd(const char *argv0, bool search_in_path)
5314 char *pathenv, *pe, binpath[PATH_MAX];
5317 if (search_in_path && strchr(argv0, '/') == NULL) {
5318 pathenv = getenv("PATH");
5319 if (pathenv == NULL) {
5320 rtld_printf("-p and no PATH environment variable\n");
5323 pathenv = strdup(pathenv);
5324 if (pathenv == NULL) {
5325 rtld_printf("Cannot allocate memory\n");
5330 while ((pe = strsep(&pathenv, ":")) != NULL) {
5331 if (strlcpy(binpath, pe, sizeof(binpath)) >=
5334 if (binpath[0] != '\0' &&
5335 strlcat(binpath, "/", sizeof(binpath)) >=
5338 if (strlcat(binpath, argv0, sizeof(binpath)) >=
5341 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
5342 if (fd != -1 || errno != ENOENT)
5347 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
5351 rtld_printf("Opening %s: %s\n", argv0,
5352 rtld_strerror(errno));
5359 * Parse a set of command-line arguments.
5362 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp)
5365 int fd, i, j, arglen;
5368 dbg("Parsing command-line arguments");
5372 for (i = 1; i < argc; i++ ) {
5374 dbg("argv[%d]: '%s'", i, arg);
5377 * rtld arguments end with an explicit "--" or with the first
5378 * non-prefixed argument.
5380 if (strcmp(arg, "--") == 0) {
5388 * All other arguments are single-character options that can
5389 * be combined, so we need to search through `arg` for them.
5391 arglen = strlen(arg);
5392 for (j = 1; j < arglen; j++) {
5395 print_usage(argv[0]);
5397 } else if (opt == 'f') {
5399 * -f XX can be used to specify a descriptor for the
5400 * binary named at the command line (i.e., the later
5401 * argument will specify the process name but the
5402 * descriptor is what will actually be executed)
5404 if (j != arglen - 1) {
5405 /* -f must be the last option in, e.g., -abcf */
5406 _rtld_error("invalid options: %s", arg);
5410 fd = parse_integer(argv[i]);
5412 _rtld_error("invalid file descriptor: '%s'",
5418 } else if (opt == 'p') {
5421 rtld_printf("invalid argument: '%s'\n", arg);
5422 print_usage(argv[0]);
5432 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
5435 parse_integer(const char *str)
5437 static const int RADIX = 10; /* XXXJA: possibly support hex? */
5444 for (c = *str; c != '\0'; c = *++str) {
5445 if (c < '0' || c > '9')
5452 /* Make sure we actually parsed something. */
5459 print_usage(const char *argv0)
5462 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n"
5465 " -h Display this help message\n"
5466 " -p Search in PATH for named binary\n"
5467 " -f <FD> Execute <FD> instead of searching for <binary>\n"
5468 " -- End of RTLD options\n"
5469 " <binary> Name of process to execute\n"
5470 " <args> Arguments to the executed process\n", argv0);
5474 * Overrides for libc_pic-provided functions.
5478 __getosreldate(void)
5488 oid[1] = KERN_OSRELDATE;
5490 len = sizeof(osrel);
5491 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5492 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5504 void (*__cleanup)(void);
5505 int __isthreaded = 0;
5506 int _thread_autoinit_dummy_decl = 1;
5509 * No unresolved symbols for rtld.
5512 __pthread_cxa_finalize(struct dl_phdr_info *a)
5517 rtld_strerror(int errnum)
5520 if (errnum < 0 || errnum >= sys_nerr)
5521 return ("Unknown error");
5522 return (sys_errlist[errnum]);