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)(void);
74 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
77 /* Variables that cannot be static: */
78 extern struct r_debug r_debug; /* For GDB */
79 extern int _thread_autoinit_dummy_decl;
80 extern char* __progname;
81 extern void (*__cleanup)(void);
85 * Function declarations.
87 static const char *basename(const char *);
88 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
89 const Elf_Dyn **, const Elf_Dyn **);
90 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
92 static void digest_dynamic(Obj_Entry *, int);
93 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
94 static Obj_Entry *dlcheck(void *);
95 static int dlclose_locked(void *, RtldLockState *);
96 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
97 int lo_flags, int mode, RtldLockState *lockstate);
98 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
99 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
100 static bool donelist_check(DoneList *, const Obj_Entry *);
101 static void errmsg_restore(char *);
102 static char *errmsg_save(void);
103 static void *fill_search_info(const char *, size_t, void *);
104 static char *find_library(const char *, const Obj_Entry *, int *);
105 static const char *gethints(bool);
106 static void hold_object(Obj_Entry *);
107 static void unhold_object(Obj_Entry *);
108 static void init_dag(Obj_Entry *);
109 static void init_marker(Obj_Entry *);
110 static void init_pagesizes(Elf_Auxinfo **aux_info);
111 static void init_rtld(caddr_t, Elf_Auxinfo **);
112 static void initlist_add_neededs(Needed_Entry *, Objlist *);
113 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *);
114 static void linkmap_add(Obj_Entry *);
115 static void linkmap_delete(Obj_Entry *);
116 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
117 static void unload_filtees(Obj_Entry *, RtldLockState *);
118 static int load_needed_objects(Obj_Entry *, int);
119 static int load_preload_objects(void);
120 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
121 static void map_stacks_exec(RtldLockState *);
122 static int obj_enforce_relro(Obj_Entry *);
123 static Obj_Entry *obj_from_addr(const void *);
124 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
125 static void objlist_call_init(Objlist *, RtldLockState *);
126 static void objlist_clear(Objlist *);
127 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
128 static void objlist_init(Objlist *);
129 static void objlist_push_head(Objlist *, Obj_Entry *);
130 static void objlist_push_tail(Objlist *, Obj_Entry *);
131 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
132 static void objlist_remove(Objlist *, Obj_Entry *);
133 static int open_binary_fd(const char *argv0, bool search_in_path);
134 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp);
135 static int parse_integer(const char *);
136 static void *path_enumerate(const char *, path_enum_proc, const char *, void *);
137 static void print_usage(const char *argv0);
138 static void release_object(Obj_Entry *);
139 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
140 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
141 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
142 int flags, RtldLockState *lockstate);
143 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
145 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *);
146 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
147 int flags, RtldLockState *lockstate);
148 static int rtld_dirname(const char *, char *);
149 static int rtld_dirname_abs(const char *, char *);
150 static void *rtld_dlopen(const char *name, int fd, int mode);
151 static void rtld_exit(void);
152 static char *search_library_path(const char *, const char *, const char *,
154 static char *search_library_pathfds(const char *, const char *, int *);
155 static const void **get_program_var_addr(const char *, RtldLockState *);
156 static void set_program_var(const char *, const void *);
157 static int symlook_default(SymLook *, const Obj_Entry *refobj);
158 static int symlook_global(SymLook *, DoneList *);
159 static void symlook_init_from_req(SymLook *, const SymLook *);
160 static int symlook_list(SymLook *, const Objlist *, DoneList *);
161 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
162 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
163 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
164 static void trace_loaded_objects(Obj_Entry *);
165 static void unlink_object(Obj_Entry *);
166 static void unload_object(Obj_Entry *, RtldLockState *lockstate);
167 static void unref_dag(Obj_Entry *);
168 static void ref_dag(Obj_Entry *);
169 static char *origin_subst_one(Obj_Entry *, char *, const char *,
171 static char *origin_subst(Obj_Entry *, const char *);
172 static bool obj_resolve_origin(Obj_Entry *obj);
173 static void preinit_main(void);
174 static int rtld_verify_versions(const Objlist *);
175 static int rtld_verify_object_versions(Obj_Entry *);
176 static void object_add_name(Obj_Entry *, const char *);
177 static int object_match_name(const Obj_Entry *, const char *);
178 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
179 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
180 struct dl_phdr_info *phdr_info);
181 static uint32_t gnu_hash(const char *);
182 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
183 const unsigned long);
185 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
186 void _r_debug_postinit(struct link_map *) __noinline __exported;
188 int __sys_openat(int, const char *, int, ...);
193 static char *error_message; /* Message for dlerror(), or NULL */
194 struct r_debug r_debug __exported; /* for GDB; */
195 static bool libmap_disable; /* Disable libmap */
196 static bool ld_loadfltr; /* Immediate filters processing */
197 static char *libmap_override; /* Maps to use in addition to libmap.conf */
198 static bool trust; /* False for setuid and setgid programs */
199 static bool dangerous_ld_env; /* True if environment variables have been
200 used to affect the libraries loaded */
201 bool ld_bind_not; /* Disable PLT update */
202 static char *ld_bind_now; /* Environment variable for immediate binding */
203 static char *ld_debug; /* Environment variable for debugging */
204 static char *ld_library_path; /* Environment variable for search path */
205 static char *ld_library_dirs; /* Environment variable for library descriptors */
206 static char *ld_preload; /* Environment variable for libraries to
208 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */
209 static const char *ld_tracing; /* Called from ldd to print libs */
210 static char *ld_utrace; /* Use utrace() to log events. */
211 static struct obj_entry_q obj_list; /* Queue of all loaded objects */
212 static Obj_Entry *obj_main; /* The main program shared object */
213 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
214 static unsigned int obj_count; /* Number of objects in obj_list */
215 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
217 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
218 STAILQ_HEAD_INITIALIZER(list_global);
219 static Objlist list_main = /* Objects loaded at program startup */
220 STAILQ_HEAD_INITIALIZER(list_main);
221 static Objlist list_fini = /* Objects needing fini() calls */
222 STAILQ_HEAD_INITIALIZER(list_fini);
224 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
226 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
228 extern Elf_Dyn _DYNAMIC;
229 #pragma weak _DYNAMIC
231 int dlclose(void *) __exported;
232 char *dlerror(void) __exported;
233 void *dlopen(const char *, int) __exported;
234 void *fdlopen(int, int) __exported;
235 void *dlsym(void *, const char *) __exported;
236 dlfunc_t dlfunc(void *, const char *) __exported;
237 void *dlvsym(void *, const char *, const char *) __exported;
238 int dladdr(const void *, Dl_info *) __exported;
239 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
240 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
241 int dlinfo(void *, int , void *) __exported;
242 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
243 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
244 int _rtld_get_stack_prot(void) __exported;
245 int _rtld_is_dlopened(void *) __exported;
246 void _rtld_error(const char *, ...) __exported;
248 /* Only here to fix -Wmissing-prototypes warnings */
249 int __getosreldate(void);
250 void __pthread_cxa_finalize(struct dl_phdr_info *a);
251 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp);
252 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff);
256 static int osreldate;
259 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
260 static int max_stack_flags;
263 * Global declarations normally provided by crt1. The dynamic linker is
264 * not built with crt1, so we have to provide them ourselves.
270 * Used to pass argc, argv to init functions.
276 * Globals to control TLS allocation.
278 size_t tls_last_offset; /* Static TLS offset of last module */
279 size_t tls_last_size; /* Static TLS size of last module */
280 size_t tls_static_space; /* Static TLS space allocated */
281 static size_t tls_static_max_align;
282 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */
283 int tls_max_index = 1; /* Largest module index allocated */
285 static bool ld_library_path_rpath = false;
288 * Globals for path names, and such
290 const char *ld_elf_hints_default = _PATH_ELF_HINTS;
291 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
292 const char *ld_path_rtld = _PATH_RTLD;
293 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
294 const char *ld_env_prefix = LD_;
297 * Fill in a DoneList with an allocation large enough to hold all of
298 * the currently-loaded objects. Keep this as a macro since it calls
299 * alloca and we want that to occur within the scope of the caller.
301 #define donelist_init(dlp) \
302 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
303 assert((dlp)->objs != NULL), \
304 (dlp)->num_alloc = obj_count, \
307 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
308 if (ld_utrace != NULL) \
309 ld_utrace_log(e, h, mb, ms, r, n); \
313 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
314 int refcnt, const char *name)
316 struct utrace_rtld ut;
317 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG;
319 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig));
322 ut.mapbase = mapbase;
323 ut.mapsize = mapsize;
325 bzero(ut.name, sizeof(ut.name));
327 strlcpy(ut.name, name, sizeof(ut.name));
328 utrace(&ut, sizeof(ut));
331 #ifdef RTLD_VARIANT_ENV_NAMES
333 * construct the env variable based on the type of binary that's
336 static inline const char *
339 static char buffer[128];
341 strlcpy(buffer, ld_env_prefix, sizeof(buffer));
342 strlcat(buffer, var, sizeof(buffer));
350 * Main entry point for dynamic linking. The first argument is the
351 * stack pointer. The stack is expected to be laid out as described
352 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
353 * Specifically, the stack pointer points to a word containing
354 * ARGC. Following that in the stack is a null-terminated sequence
355 * of pointers to argument strings. Then comes a null-terminated
356 * sequence of pointers to environment strings. Finally, there is a
357 * sequence of "auxiliary vector" entries.
359 * The second argument points to a place to store the dynamic linker's
360 * exit procedure pointer and the third to a place to store the main
363 * The return value is the main program's entry point.
366 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
368 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT];
369 Objlist_Entry *entry;
370 Obj_Entry *last_interposer, *obj, *preload_tail;
371 const Elf_Phdr *phdr;
373 RtldLockState lockstate;
376 char **argv, **env, **envp, *kexecpath, *library_path_rpath;
379 char buf[MAXPATHLEN];
380 int argc, fd, i, phnum, rtld_argc;
381 bool dir_enable, explicit_fd, search_in_path;
384 * On entry, the dynamic linker itself has not been relocated yet.
385 * Be very careful not to reference any global data until after
386 * init_rtld has returned. It is OK to reference file-scope statics
387 * and string constants, and to call static and global functions.
390 /* Find the auxiliary vector on the stack. */
394 sp += argc + 1; /* Skip over arguments and NULL terminator */
396 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
398 aux = (Elf_Auxinfo *) sp;
400 /* Digest the auxiliary vector. */
401 for (i = 0; i < AT_COUNT; i++)
403 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
404 if (auxp->a_type < AT_COUNT)
405 aux_info[auxp->a_type] = auxp;
408 /* Initialize and relocate ourselves. */
409 assert(aux_info[AT_BASE] != NULL);
410 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
412 __progname = obj_rtld.path;
413 argv0 = argv[0] != NULL ? argv[0] : "(null)";
418 trust = !issetugid();
420 md_abi_variant_hook(aux_info);
423 if (aux_info[AT_EXECFD] != NULL) {
424 fd = aux_info[AT_EXECFD]->a_un.a_val;
426 assert(aux_info[AT_PHDR] != NULL);
427 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
428 if (phdr == obj_rtld.phdr) {
430 _rtld_error("Tainted process refusing to run binary %s",
434 dbg("opening main program in direct exec mode");
436 rtld_argc = parse_args(argv, argc, &search_in_path, &fd);
437 argv0 = argv[rtld_argc];
438 explicit_fd = (fd != -1);
440 fd = open_binary_fd(argv0, search_in_path);
441 if (fstat(fd, &st) == -1) {
442 _rtld_error("Failed to fstat FD %d (%s): %s", fd,
443 explicit_fd ? "user-provided descriptor" : argv0,
444 rtld_strerror(errno));
449 * Rough emulation of the permission checks done by
450 * execve(2), only Unix DACs are checked, ACLs are
451 * ignored. Preserve the semantic of disabling owner
452 * to execute if owner x bit is cleared, even if
453 * others x bit is enabled.
454 * mmap(2) does not allow to mmap with PROT_EXEC if
455 * binary' file comes from noexec mount. We cannot
456 * set VV_TEXT on the binary.
459 if (st.st_uid == geteuid()) {
460 if ((st.st_mode & S_IXUSR) != 0)
462 } else if (st.st_gid == getegid()) {
463 if ((st.st_mode & S_IXGRP) != 0)
465 } else if ((st.st_mode & S_IXOTH) != 0) {
469 _rtld_error("No execute permission for binary %s",
475 * For direct exec mode, argv[0] is the interpreter
476 * name, we must remove it and shift arguments left
477 * before invoking binary main. Since stack layout
478 * places environment pointers and aux vectors right
479 * after the terminating NULL, we must shift
480 * environment and aux as well.
482 main_argc = argc - rtld_argc;
483 for (i = 0; i <= main_argc; i++)
484 argv[i] = argv[i + rtld_argc];
486 environ = env = envp = argv + main_argc + 1;
488 *envp = *(envp + rtld_argc);
490 } while (*envp != NULL);
491 aux = auxp = (Elf_Auxinfo *)envp;
492 auxpf = (Elf_Auxinfo *)(envp + rtld_argc);
493 for (;; auxp++, auxpf++) {
495 if (auxp->a_type == AT_NULL)
499 _rtld_error("No binary");
505 ld_bind_now = getenv(_LD("BIND_NOW"));
508 * If the process is tainted, then we un-set the dangerous environment
509 * variables. The process will be marked as tainted until setuid(2)
510 * is called. If any child process calls setuid(2) we do not want any
511 * future processes to honor the potentially un-safe variables.
514 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) ||
515 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) ||
516 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) ||
517 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) ||
518 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) {
519 _rtld_error("environment corrupt; aborting");
523 ld_debug = getenv(_LD("DEBUG"));
524 if (ld_bind_now == NULL)
525 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL;
526 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL;
527 libmap_override = getenv(_LD("LIBMAP"));
528 ld_library_path = getenv(_LD("LIBRARY_PATH"));
529 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS"));
530 ld_preload = getenv(_LD("PRELOAD"));
531 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH"));
532 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL;
533 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH"));
534 if (library_path_rpath != NULL) {
535 if (library_path_rpath[0] == 'y' ||
536 library_path_rpath[0] == 'Y' ||
537 library_path_rpath[0] == '1')
538 ld_library_path_rpath = true;
540 ld_library_path_rpath = false;
542 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
543 (ld_library_path != NULL) || (ld_preload != NULL) ||
544 (ld_elf_hints_path != NULL) || ld_loadfltr;
545 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS"));
546 ld_utrace = getenv(_LD("UTRACE"));
548 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
549 ld_elf_hints_path = ld_elf_hints_default;
551 if (ld_debug != NULL && *ld_debug != '\0')
553 dbg("%s is initialized, base address = %p", __progname,
554 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
555 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
556 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
558 dbg("initializing thread locks");
562 * Load the main program, or process its program header if it is
565 if (fd != -1) { /* Load the main program. */
566 dbg("loading main program");
567 obj_main = map_object(fd, argv0, NULL);
569 if (obj_main == NULL)
571 max_stack_flags = obj_main->stack_flags;
572 } else { /* Main program already loaded. */
573 dbg("processing main program's program header");
574 assert(aux_info[AT_PHDR] != NULL);
575 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
576 assert(aux_info[AT_PHNUM] != NULL);
577 phnum = aux_info[AT_PHNUM]->a_un.a_val;
578 assert(aux_info[AT_PHENT] != NULL);
579 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
580 assert(aux_info[AT_ENTRY] != NULL);
581 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
582 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL)
586 if (aux_info[AT_EXECPATH] != NULL && fd == -1) {
587 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
588 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
589 if (kexecpath[0] == '/')
590 obj_main->path = kexecpath;
591 else if (getcwd(buf, sizeof(buf)) == NULL ||
592 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
593 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
594 obj_main->path = xstrdup(argv0);
596 obj_main->path = xstrdup(buf);
598 dbg("No AT_EXECPATH or direct exec");
599 obj_main->path = xstrdup(argv0);
601 dbg("obj_main path %s", obj_main->path);
602 obj_main->mainprog = true;
604 if (aux_info[AT_STACKPROT] != NULL &&
605 aux_info[AT_STACKPROT]->a_un.a_val != 0)
606 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
610 * Get the actual dynamic linker pathname from the executable if
611 * possible. (It should always be possible.) That ensures that
612 * gdb will find the right dynamic linker even if a non-standard
615 if (obj_main->interp != NULL &&
616 strcmp(obj_main->interp, obj_rtld.path) != 0) {
618 obj_rtld.path = xstrdup(obj_main->interp);
619 __progname = obj_rtld.path;
623 digest_dynamic(obj_main, 0);
624 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
625 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
626 obj_main->dynsymcount);
628 linkmap_add(obj_main);
629 linkmap_add(&obj_rtld);
631 /* Link the main program into the list of objects. */
632 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
636 /* Initialize a fake symbol for resolving undefined weak references. */
637 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
638 sym_zero.st_shndx = SHN_UNDEF;
639 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
642 libmap_disable = (bool)lm_init(libmap_override);
644 dbg("loading LD_PRELOAD libraries");
645 if (load_preload_objects() == -1)
647 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
649 dbg("loading needed objects");
650 if (load_needed_objects(obj_main, 0) == -1)
653 /* Make a list of all objects loaded at startup. */
654 last_interposer = obj_main;
655 TAILQ_FOREACH(obj, &obj_list, next) {
658 if (obj->z_interpose && obj != obj_main) {
659 objlist_put_after(&list_main, last_interposer, obj);
660 last_interposer = obj;
662 objlist_push_tail(&list_main, obj);
667 dbg("checking for required versions");
668 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
671 if (ld_tracing) { /* We're done */
672 trace_loaded_objects(obj_main);
676 if (getenv(_LD("DUMP_REL_PRE")) != NULL) {
677 dump_relocations(obj_main);
682 * Processing tls relocations requires having the tls offsets
683 * initialized. Prepare offsets before starting initial
684 * relocation processing.
686 dbg("initializing initial thread local storage offsets");
687 STAILQ_FOREACH(entry, &list_main, link) {
689 * Allocate all the initial objects out of the static TLS
690 * block even if they didn't ask for it.
692 allocate_tls_offset(entry->obj);
695 if (relocate_objects(obj_main,
696 ld_bind_now != NULL && *ld_bind_now != '\0',
697 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
700 dbg("doing copy relocations");
701 if (do_copy_relocations(obj_main) == -1)
704 if (getenv(_LD("DUMP_REL_POST")) != NULL) {
705 dump_relocations(obj_main);
712 * Setup TLS for main thread. This must be done after the
713 * relocations are processed, since tls initialization section
714 * might be the subject for relocations.
716 dbg("initializing initial thread local storage");
717 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
719 dbg("initializing key program variables");
720 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
721 set_program_var("environ", env);
722 set_program_var("__elf_aux_vector", aux);
724 /* Make a list of init functions to call. */
725 objlist_init(&initlist);
726 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)),
727 preload_tail, &initlist);
729 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
731 map_stacks_exec(NULL);
733 dbg("resolving ifuncs");
734 if (resolve_objects_ifunc(obj_main,
735 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
739 dbg("enforcing main obj relro");
740 if (obj_enforce_relro(obj_main) == -1)
743 if (!obj_main->crt_no_init) {
745 * Make sure we don't call the main program's init and fini
746 * functions for binaries linked with old crt1 which calls
749 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
750 obj_main->preinit_array = obj_main->init_array =
751 obj_main->fini_array = (Elf_Addr)NULL;
755 * Execute MD initializers required before we call the objects'
760 wlock_acquire(rtld_bind_lock, &lockstate);
761 if (obj_main->crt_no_init)
763 objlist_call_init(&initlist, &lockstate);
764 _r_debug_postinit(&obj_main->linkmap);
765 objlist_clear(&initlist);
766 dbg("loading filtees");
767 TAILQ_FOREACH(obj, &obj_list, next) {
770 if (ld_loadfltr || obj->z_loadfltr)
771 load_filtees(obj, 0, &lockstate);
773 lock_release(rtld_bind_lock, &lockstate);
775 dbg("transferring control to program entry point = %p", obj_main->entry);
777 /* Return the exit procedure and the program entry point. */
778 *exit_proc = rtld_exit;
780 return (func_ptr_type) obj_main->entry;
784 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
789 ptr = (void *)make_function_pointer(def, obj);
790 target = call_ifunc_resolver(ptr);
791 return ((void *)target);
795 * NB: MIPS uses a private version of this function (_mips_rtld_bind).
796 * Changes to this function should be applied there as well.
799 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
803 const Obj_Entry *defobj;
806 RtldLockState lockstate;
808 rlock_acquire(rtld_bind_lock, &lockstate);
809 if (sigsetjmp(lockstate.env, 0) != 0)
810 lock_upgrade(rtld_bind_lock, &lockstate);
812 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff);
814 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff);
816 where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
817 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
821 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
822 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
824 target = (Elf_Addr)(defobj->relocbase + def->st_value);
826 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
827 defobj->strtab + def->st_name, basename(obj->path),
828 (void *)target, basename(defobj->path));
831 * Write the new contents for the jmpslot. Note that depending on
832 * architecture, the value which we need to return back to the
833 * lazy binding trampoline may or may not be the target
834 * address. The value returned from reloc_jmpslot() is the value
835 * that the trampoline needs.
837 target = reloc_jmpslot(where, target, defobj, obj, rel);
838 lock_release(rtld_bind_lock, &lockstate);
843 * Error reporting function. Use it like printf. If formats the message
844 * into a buffer, and sets things up so that the next call to dlerror()
845 * will return the message.
848 _rtld_error(const char *fmt, ...)
850 static char buf[512];
854 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
857 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message);
861 * Return a dynamically-allocated copy of the current error message, if any.
866 return error_message == NULL ? NULL : xstrdup(error_message);
870 * Restore the current error message from a copy which was previously saved
871 * by errmsg_save(). The copy is freed.
874 errmsg_restore(char *saved_msg)
876 if (saved_msg == NULL)
877 error_message = NULL;
879 _rtld_error("%s", saved_msg);
885 basename(const char *name)
887 const char *p = strrchr(name, '/');
888 return p != NULL ? p + 1 : name;
891 static struct utsname uts;
894 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
895 const char *subst, bool may_free)
897 char *p, *p1, *res, *resp;
898 int subst_len, kw_len, subst_count, old_len, new_len;
903 * First, count the number of the keyword occurrences, to
904 * preallocate the final string.
906 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
913 * If the keyword is not found, just return.
915 * Return non-substituted string if resolution failed. We
916 * cannot do anything more reasonable, the failure mode of the
917 * caller is unresolved library anyway.
919 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
920 return (may_free ? real : xstrdup(real));
922 subst = obj->origin_path;
925 * There is indeed something to substitute. Calculate the
926 * length of the resulting string, and allocate it.
928 subst_len = strlen(subst);
929 old_len = strlen(real);
930 new_len = old_len + (subst_len - kw_len) * subst_count;
931 res = xmalloc(new_len + 1);
934 * Now, execute the substitution loop.
936 for (p = real, resp = res, *resp = '\0';;) {
939 /* Copy the prefix before keyword. */
940 memcpy(resp, p, p1 - p);
942 /* Keyword replacement. */
943 memcpy(resp, subst, subst_len);
951 /* Copy to the end of string and finish. */
959 origin_subst(Obj_Entry *obj, const char *real)
961 char *res1, *res2, *res3, *res4;
963 if (obj == NULL || !trust)
964 return (xstrdup(real));
965 if (uts.sysname[0] == '\0') {
966 if (uname(&uts) != 0) {
967 _rtld_error("utsname failed: %d", errno);
971 /* __DECONST is safe here since without may_free real is unchanged */
972 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL,
974 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
975 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
976 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
983 const char *msg = dlerror();
987 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": ");
988 rtld_fdputstr(STDERR_FILENO, msg);
989 rtld_fdputchar(STDERR_FILENO, '\n');
994 * Process a shared object's DYNAMIC section, and save the important
995 * information in its Obj_Entry structure.
998 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
999 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
1001 const Elf_Dyn *dynp;
1002 Needed_Entry **needed_tail = &obj->needed;
1003 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
1004 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
1005 const Elf_Hashelt *hashtab;
1006 const Elf32_Word *hashval;
1007 Elf32_Word bkt, nmaskwords;
1009 int plttype = DT_REL;
1013 *dyn_runpath = NULL;
1015 obj->bind_now = false;
1016 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
1017 switch (dynp->d_tag) {
1020 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr);
1024 obj->relsize = dynp->d_un.d_val;
1028 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1032 obj->pltrel = (const Elf_Rel *)
1033 (obj->relocbase + dynp->d_un.d_ptr);
1037 obj->pltrelsize = dynp->d_un.d_val;
1041 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr);
1045 obj->relasize = dynp->d_un.d_val;
1049 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1053 plttype = dynp->d_un.d_val;
1054 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1058 obj->symtab = (const Elf_Sym *)
1059 (obj->relocbase + dynp->d_un.d_ptr);
1063 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1067 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr);
1071 obj->strsize = dynp->d_un.d_val;
1075 obj->verneed = (const Elf_Verneed *)(obj->relocbase +
1080 obj->verneednum = dynp->d_un.d_val;
1084 obj->verdef = (const Elf_Verdef *)(obj->relocbase +
1089 obj->verdefnum = dynp->d_un.d_val;
1093 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1099 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1101 obj->nbuckets = hashtab[0];
1102 obj->nchains = hashtab[1];
1103 obj->buckets = hashtab + 2;
1104 obj->chains = obj->buckets + obj->nbuckets;
1105 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1106 obj->buckets != NULL;
1112 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1114 obj->nbuckets_gnu = hashtab[0];
1115 obj->symndx_gnu = hashtab[1];
1116 nmaskwords = hashtab[2];
1117 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1118 obj->maskwords_bm_gnu = nmaskwords - 1;
1119 obj->shift2_gnu = hashtab[3];
1120 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4);
1121 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1122 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1124 /* Number of bitmask words is required to be power of 2 */
1125 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1126 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1132 Needed_Entry *nep = NEW(Needed_Entry);
1133 nep->name = dynp->d_un.d_val;
1138 needed_tail = &nep->next;
1144 Needed_Entry *nep = NEW(Needed_Entry);
1145 nep->name = dynp->d_un.d_val;
1149 *needed_filtees_tail = nep;
1150 needed_filtees_tail = &nep->next;
1156 Needed_Entry *nep = NEW(Needed_Entry);
1157 nep->name = dynp->d_un.d_val;
1161 *needed_aux_filtees_tail = nep;
1162 needed_aux_filtees_tail = &nep->next;
1167 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr);
1171 obj->textrel = true;
1175 obj->symbolic = true;
1180 * We have to wait until later to process this, because we
1181 * might not have gotten the address of the string table yet.
1191 *dyn_runpath = dynp;
1195 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1198 case DT_PREINIT_ARRAY:
1199 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1202 case DT_PREINIT_ARRAYSZ:
1203 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1207 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1210 case DT_INIT_ARRAYSZ:
1211 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1215 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1219 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1222 case DT_FINI_ARRAYSZ:
1223 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1227 * Don't process DT_DEBUG on MIPS as the dynamic section
1228 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1234 dbg("Filling in DT_DEBUG entry");
1235 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug;
1240 if (dynp->d_un.d_val & DF_ORIGIN)
1241 obj->z_origin = true;
1242 if (dynp->d_un.d_val & DF_SYMBOLIC)
1243 obj->symbolic = true;
1244 if (dynp->d_un.d_val & DF_TEXTREL)
1245 obj->textrel = true;
1246 if (dynp->d_un.d_val & DF_BIND_NOW)
1247 obj->bind_now = true;
1248 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1252 case DT_MIPS_LOCAL_GOTNO:
1253 obj->local_gotno = dynp->d_un.d_val;
1256 case DT_MIPS_SYMTABNO:
1257 obj->symtabno = dynp->d_un.d_val;
1260 case DT_MIPS_GOTSYM:
1261 obj->gotsym = dynp->d_un.d_val;
1264 case DT_MIPS_RLD_MAP:
1265 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1268 case DT_MIPS_RLD_MAP_REL:
1269 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map
1270 // section relative to the address of the tag itself.
1271 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) =
1272 (Elf_Addr) &r_debug;
1275 case DT_MIPS_PLTGOT:
1276 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase +
1282 #ifdef __powerpc64__
1283 case DT_PPC64_GLINK:
1284 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1289 if (dynp->d_un.d_val & DF_1_NOOPEN)
1290 obj->z_noopen = true;
1291 if (dynp->d_un.d_val & DF_1_ORIGIN)
1292 obj->z_origin = true;
1293 if (dynp->d_un.d_val & DF_1_GLOBAL)
1294 obj->z_global = true;
1295 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1296 obj->bind_now = true;
1297 if (dynp->d_un.d_val & DF_1_NODELETE)
1298 obj->z_nodelete = true;
1299 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1300 obj->z_loadfltr = true;
1301 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1302 obj->z_interpose = true;
1303 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1304 obj->z_nodeflib = true;
1309 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1316 obj->traced = false;
1318 if (plttype == DT_RELA) {
1319 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1321 obj->pltrelasize = obj->pltrelsize;
1322 obj->pltrelsize = 0;
1325 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1326 if (obj->valid_hash_sysv)
1327 obj->dynsymcount = obj->nchains;
1328 else if (obj->valid_hash_gnu) {
1329 obj->dynsymcount = 0;
1330 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1331 if (obj->buckets_gnu[bkt] == 0)
1333 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1336 while ((*hashval++ & 1u) == 0);
1338 obj->dynsymcount += obj->symndx_gnu;
1343 obj_resolve_origin(Obj_Entry *obj)
1346 if (obj->origin_path != NULL)
1348 obj->origin_path = xmalloc(PATH_MAX);
1349 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1353 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1354 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1357 if (obj->z_origin && !obj_resolve_origin(obj))
1360 if (dyn_runpath != NULL) {
1361 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val;
1362 obj->runpath = origin_subst(obj, obj->runpath);
1363 } else if (dyn_rpath != NULL) {
1364 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val;
1365 obj->rpath = origin_subst(obj, obj->rpath);
1367 if (dyn_soname != NULL)
1368 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1372 digest_dynamic(Obj_Entry *obj, int early)
1374 const Elf_Dyn *dyn_rpath;
1375 const Elf_Dyn *dyn_soname;
1376 const Elf_Dyn *dyn_runpath;
1378 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1379 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1383 * Process a shared object's program header. This is used only for the
1384 * main program, when the kernel has already loaded the main program
1385 * into memory before calling the dynamic linker. It creates and
1386 * returns an Obj_Entry structure.
1389 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1392 const Elf_Phdr *phlimit = phdr + phnum;
1394 Elf_Addr note_start, note_end;
1398 for (ph = phdr; ph < phlimit; ph++) {
1399 if (ph->p_type != PT_PHDR)
1403 obj->phsize = ph->p_memsz;
1404 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr;
1408 obj->stack_flags = PF_X | PF_R | PF_W;
1410 for (ph = phdr; ph < phlimit; ph++) {
1411 switch (ph->p_type) {
1414 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1418 if (nsegs == 0) { /* First load segment */
1419 obj->vaddrbase = trunc_page(ph->p_vaddr);
1420 obj->mapbase = obj->vaddrbase + obj->relocbase;
1421 } else { /* Last load segment */
1422 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1429 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1434 obj->tlssize = ph->p_memsz;
1435 obj->tlsalign = ph->p_align;
1436 obj->tlsinitsize = ph->p_filesz;
1437 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1441 obj->stack_flags = ph->p_flags;
1445 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1446 obj->relro_size = round_page(ph->p_memsz);
1450 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1451 note_end = note_start + ph->p_filesz;
1452 digest_notes(obj, note_start, note_end);
1457 _rtld_error("%s: too few PT_LOAD segments", path);
1466 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1468 const Elf_Note *note;
1469 const char *note_name;
1472 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1473 note = (const Elf_Note *)((const char *)(note + 1) +
1474 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1475 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1476 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1477 note->n_descsz != sizeof(int32_t))
1479 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1480 note->n_type != NT_FREEBSD_NOINIT_TAG)
1482 note_name = (const char *)(note + 1);
1483 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1484 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1486 switch (note->n_type) {
1487 case NT_FREEBSD_ABI_TAG:
1488 /* FreeBSD osrel note */
1489 p = (uintptr_t)(note + 1);
1490 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1491 obj->osrel = *(const int32_t *)(p);
1492 dbg("note osrel %d", obj->osrel);
1494 case NT_FREEBSD_NOINIT_TAG:
1495 /* FreeBSD 'crt does not call init' note */
1496 obj->crt_no_init = true;
1497 dbg("note crt_no_init");
1504 dlcheck(void *handle)
1508 TAILQ_FOREACH(obj, &obj_list, next) {
1509 if (obj == (Obj_Entry *) handle)
1513 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1514 _rtld_error("Invalid shared object handle %p", handle);
1521 * If the given object is already in the donelist, return true. Otherwise
1522 * add the object to the list and return false.
1525 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1529 for (i = 0; i < dlp->num_used; i++)
1530 if (dlp->objs[i] == obj)
1533 * Our donelist allocation should always be sufficient. But if
1534 * our threads locking isn't working properly, more shared objects
1535 * could have been loaded since we allocated the list. That should
1536 * never happen, but we'll handle it properly just in case it does.
1538 if (dlp->num_used < dlp->num_alloc)
1539 dlp->objs[dlp->num_used++] = obj;
1544 * Hash function for symbol table lookup. Don't even think about changing
1545 * this. It is specified by the System V ABI.
1548 elf_hash(const char *name)
1550 const unsigned char *p = (const unsigned char *) name;
1551 unsigned long h = 0;
1554 while (*p != '\0') {
1555 h = (h << 4) + *p++;
1556 if ((g = h & 0xf0000000) != 0)
1564 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1565 * unsigned in case it's implemented with a wider type.
1568 gnu_hash(const char *s)
1574 for (c = *s; c != '\0'; c = *++s)
1576 return (h & 0xffffffff);
1581 * Find the library with the given name, and return its full pathname.
1582 * The returned string is dynamically allocated. Generates an error
1583 * message and returns NULL if the library cannot be found.
1585 * If the second argument is non-NULL, then it refers to an already-
1586 * loaded shared object, whose library search path will be searched.
1588 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1589 * descriptor (which is close-on-exec) will be passed out via the third
1592 * The search order is:
1593 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1594 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1596 * DT_RUNPATH in the referencing file
1597 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1599 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1601 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1604 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1606 char *pathname, *refobj_path;
1608 bool nodeflib, objgiven;
1610 objgiven = refobj != NULL;
1612 if (libmap_disable || !objgiven ||
1613 (name = lm_find(refobj->path, xname)) == NULL)
1616 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1617 if (name[0] != '/' && !trust) {
1618 _rtld_error("Absolute pathname required "
1619 "for shared object \"%s\"", name);
1622 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1623 __DECONST(char *, name)));
1626 dbg(" Searching for \"%s\"", name);
1627 refobj_path = objgiven ? refobj->path : NULL;
1630 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1631 * back to pre-conforming behaviour if user requested so with
1632 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1635 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1636 pathname = search_library_path(name, ld_library_path,
1638 if (pathname != NULL)
1640 if (refobj != NULL) {
1641 pathname = search_library_path(name, refobj->rpath,
1643 if (pathname != NULL)
1646 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1647 if (pathname != NULL)
1649 pathname = search_library_path(name, gethints(false),
1651 if (pathname != NULL)
1653 pathname = search_library_path(name, ld_standard_library_path,
1655 if (pathname != NULL)
1658 nodeflib = objgiven ? refobj->z_nodeflib : false;
1660 pathname = search_library_path(name, refobj->rpath,
1662 if (pathname != NULL)
1665 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1666 pathname = search_library_path(name, obj_main->rpath,
1668 if (pathname != NULL)
1671 pathname = search_library_path(name, ld_library_path,
1673 if (pathname != NULL)
1676 pathname = search_library_path(name, refobj->runpath,
1678 if (pathname != NULL)
1681 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1682 if (pathname != NULL)
1684 pathname = search_library_path(name, gethints(nodeflib),
1686 if (pathname != NULL)
1688 if (objgiven && !nodeflib) {
1689 pathname = search_library_path(name,
1690 ld_standard_library_path, refobj_path, fdp);
1691 if (pathname != NULL)
1696 if (objgiven && refobj->path != NULL) {
1697 _rtld_error("Shared object \"%s\" not found, "
1698 "required by \"%s\"", name, basename(refobj->path));
1700 _rtld_error("Shared object \"%s\" not found", name);
1706 * Given a symbol number in a referencing object, find the corresponding
1707 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1708 * no definition was found. Returns a pointer to the Obj_Entry of the
1709 * defining object via the reference parameter DEFOBJ_OUT.
1712 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1713 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1714 RtldLockState *lockstate)
1718 const Obj_Entry *defobj;
1719 const Ver_Entry *ve;
1725 * If we have already found this symbol, get the information from
1728 if (symnum >= refobj->dynsymcount)
1729 return NULL; /* Bad object */
1730 if (cache != NULL && cache[symnum].sym != NULL) {
1731 *defobj_out = cache[symnum].obj;
1732 return cache[symnum].sym;
1735 ref = refobj->symtab + symnum;
1736 name = refobj->strtab + ref->st_name;
1742 * We don't have to do a full scale lookup if the symbol is local.
1743 * We know it will bind to the instance in this load module; to
1744 * which we already have a pointer (ie ref). By not doing a lookup,
1745 * we not only improve performance, but it also avoids unresolvable
1746 * symbols when local symbols are not in the hash table. This has
1747 * been seen with the ia64 toolchain.
1749 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1750 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1751 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1754 symlook_init(&req, name);
1756 ve = req.ventry = fetch_ventry(refobj, symnum);
1757 req.lockstate = lockstate;
1758 res = symlook_default(&req, refobj);
1761 defobj = req.defobj_out;
1769 * If we found no definition and the reference is weak, treat the
1770 * symbol as having the value zero.
1772 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1778 *defobj_out = defobj;
1779 /* Record the information in the cache to avoid subsequent lookups. */
1780 if (cache != NULL) {
1781 cache[symnum].sym = def;
1782 cache[symnum].obj = defobj;
1785 if (refobj != &obj_rtld)
1786 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name,
1787 ve != NULL ? "@" : "", ve != NULL ? ve->name : "");
1793 * Return the search path from the ldconfig hints file, reading it if
1794 * necessary. If nostdlib is true, then the default search paths are
1795 * not added to result.
1797 * Returns NULL if there are problems with the hints file,
1798 * or if the search path there is empty.
1801 gethints(bool nostdlib)
1803 static char *filtered_path;
1804 static const char *hints;
1805 static struct elfhints_hdr hdr;
1806 struct fill_search_info_args sargs, hargs;
1807 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1808 struct dl_serpath *SLPpath, *hintpath;
1810 struct stat hint_stat;
1811 unsigned int SLPndx, hintndx, fndx, fcount;
1817 /* First call, read the hints file */
1818 if (hints == NULL) {
1819 /* Keep from trying again in case the hints file is bad. */
1822 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1826 * Check of hdr.dirlistlen value against type limit
1827 * intends to pacify static analyzers. Further
1828 * paranoia leads to checks that dirlist is fully
1829 * contained in the file range.
1831 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1832 hdr.magic != ELFHINTS_MAGIC ||
1833 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 ||
1834 fstat(fd, &hint_stat) == -1) {
1841 if (dl + hdr.dirlist < dl)
1844 if (dl + hdr.dirlistlen < dl)
1846 dl += hdr.dirlistlen;
1847 if (dl > hint_stat.st_size)
1849 p = xmalloc(hdr.dirlistlen + 1);
1850 if (pread(fd, p, hdr.dirlistlen + 1,
1851 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 ||
1852 p[hdr.dirlistlen] != '\0') {
1861 * If caller agreed to receive list which includes the default
1862 * paths, we are done. Otherwise, if we still did not
1863 * calculated filtered result, do it now.
1866 return (hints[0] != '\0' ? hints : NULL);
1867 if (filtered_path != NULL)
1871 * Obtain the list of all configured search paths, and the
1872 * list of the default paths.
1874 * First estimate the size of the results.
1876 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1878 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1881 sargs.request = RTLD_DI_SERINFOSIZE;
1882 sargs.serinfo = &smeta;
1883 hargs.request = RTLD_DI_SERINFOSIZE;
1884 hargs.serinfo = &hmeta;
1886 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1888 path_enumerate(hints, fill_search_info, NULL, &hargs);
1890 SLPinfo = xmalloc(smeta.dls_size);
1891 hintinfo = xmalloc(hmeta.dls_size);
1894 * Next fetch both sets of paths.
1896 sargs.request = RTLD_DI_SERINFO;
1897 sargs.serinfo = SLPinfo;
1898 sargs.serpath = &SLPinfo->dls_serpath[0];
1899 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1901 hargs.request = RTLD_DI_SERINFO;
1902 hargs.serinfo = hintinfo;
1903 hargs.serpath = &hintinfo->dls_serpath[0];
1904 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1906 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1908 path_enumerate(hints, fill_search_info, NULL, &hargs);
1911 * Now calculate the difference between two sets, by excluding
1912 * standard paths from the full set.
1916 filtered_path = xmalloc(hdr.dirlistlen + 1);
1917 hintpath = &hintinfo->dls_serpath[0];
1918 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1920 SLPpath = &SLPinfo->dls_serpath[0];
1922 * Check each standard path against current.
1924 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1925 /* matched, skip the path */
1926 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1934 * Not matched against any standard path, add the path
1935 * to result. Separate consequtive paths with ':'.
1938 filtered_path[fndx] = ':';
1942 flen = strlen(hintpath->dls_name);
1943 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1946 filtered_path[fndx] = '\0';
1952 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1956 init_dag(Obj_Entry *root)
1958 const Needed_Entry *needed;
1959 const Objlist_Entry *elm;
1962 if (root->dag_inited)
1964 donelist_init(&donelist);
1966 /* Root object belongs to own DAG. */
1967 objlist_push_tail(&root->dldags, root);
1968 objlist_push_tail(&root->dagmembers, root);
1969 donelist_check(&donelist, root);
1972 * Add dependencies of root object to DAG in breadth order
1973 * by exploiting the fact that each new object get added
1974 * to the tail of the dagmembers list.
1976 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1977 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1978 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1980 objlist_push_tail(&needed->obj->dldags, root);
1981 objlist_push_tail(&root->dagmembers, needed->obj);
1984 root->dag_inited = true;
1988 init_marker(Obj_Entry *marker)
1991 bzero(marker, sizeof(*marker));
1992 marker->marker = true;
1996 globallist_curr(const Obj_Entry *obj)
2003 return (__DECONST(Obj_Entry *, obj));
2004 obj = TAILQ_PREV(obj, obj_entry_q, next);
2009 globallist_next(const Obj_Entry *obj)
2013 obj = TAILQ_NEXT(obj, next);
2017 return (__DECONST(Obj_Entry *, obj));
2021 /* Prevent the object from being unmapped while the bind lock is dropped. */
2023 hold_object(Obj_Entry *obj)
2030 unhold_object(Obj_Entry *obj)
2033 assert(obj->holdcount > 0);
2034 if (--obj->holdcount == 0 && obj->unholdfree)
2035 release_object(obj);
2039 process_z(Obj_Entry *root)
2041 const Objlist_Entry *elm;
2045 * Walk over object DAG and process every dependent object
2046 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2047 * to grow their own DAG.
2049 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2050 * symlook_global() to work.
2052 * For DF_1_NODELETE, the DAG should have its reference upped.
2054 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2058 if (obj->z_nodelete && !obj->ref_nodel) {
2059 dbg("obj %s -z nodelete", obj->path);
2062 obj->ref_nodel = true;
2064 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2065 dbg("obj %s -z global", obj->path);
2066 objlist_push_tail(&list_global, obj);
2072 * Initialize the dynamic linker. The argument is the address at which
2073 * the dynamic linker has been mapped into memory. The primary task of
2074 * this function is to relocate the dynamic linker.
2077 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2079 Obj_Entry objtmp; /* Temporary rtld object */
2080 const Elf_Ehdr *ehdr;
2081 const Elf_Dyn *dyn_rpath;
2082 const Elf_Dyn *dyn_soname;
2083 const Elf_Dyn *dyn_runpath;
2085 #ifdef RTLD_INIT_PAGESIZES_EARLY
2086 /* The page size is required by the dynamic memory allocator. */
2087 init_pagesizes(aux_info);
2091 * Conjure up an Obj_Entry structure for the dynamic linker.
2093 * The "path" member can't be initialized yet because string constants
2094 * cannot yet be accessed. Below we will set it correctly.
2096 memset(&objtmp, 0, sizeof(objtmp));
2099 objtmp.mapbase = mapbase;
2101 objtmp.relocbase = mapbase;
2104 objtmp.dynamic = rtld_dynamic(&objtmp);
2105 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2106 assert(objtmp.needed == NULL);
2107 #if !defined(__mips__)
2108 /* MIPS has a bogus DT_TEXTREL. */
2109 assert(!objtmp.textrel);
2112 * Temporarily put the dynamic linker entry into the object list, so
2113 * that symbols can be found.
2115 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2117 ehdr = (Elf_Ehdr *)mapbase;
2118 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2119 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]);
2121 /* Initialize the object list. */
2122 TAILQ_INIT(&obj_list);
2124 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2125 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2127 #ifndef RTLD_INIT_PAGESIZES_EARLY
2128 /* The page size is required by the dynamic memory allocator. */
2129 init_pagesizes(aux_info);
2132 if (aux_info[AT_OSRELDATE] != NULL)
2133 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2135 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2137 /* Replace the path with a dynamically allocated copy. */
2138 obj_rtld.path = xstrdup(ld_path_rtld);
2140 r_debug.r_brk = r_debug_state;
2141 r_debug.r_state = RT_CONSISTENT;
2145 * Retrieve the array of supported page sizes. The kernel provides the page
2146 * sizes in increasing order.
2149 init_pagesizes(Elf_Auxinfo **aux_info)
2151 static size_t psa[MAXPAGESIZES];
2155 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
2157 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2158 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2161 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2164 /* As a fallback, retrieve the base page size. */
2165 size = sizeof(psa[0]);
2166 if (aux_info[AT_PAGESZ] != NULL) {
2167 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2171 mib[1] = HW_PAGESIZE;
2175 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2176 _rtld_error("sysctl for hw.pagesize(s) failed");
2182 npagesizes = size / sizeof(pagesizes[0]);
2183 /* Discard any invalid entries at the end of the array. */
2184 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2189 * Add the init functions from a needed object list (and its recursive
2190 * needed objects) to "list". This is not used directly; it is a helper
2191 * function for initlist_add_objects(). The write lock must be held
2192 * when this function is called.
2195 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
2197 /* Recursively process the successor needed objects. */
2198 if (needed->next != NULL)
2199 initlist_add_neededs(needed->next, list);
2201 /* Process the current needed object. */
2202 if (needed->obj != NULL)
2203 initlist_add_objects(needed->obj, needed->obj, list);
2207 * Scan all of the DAGs rooted in the range of objects from "obj" to
2208 * "tail" and add their init functions to "list". This recurses over
2209 * the DAGs and ensure the proper init ordering such that each object's
2210 * needed libraries are initialized before the object itself. At the
2211 * same time, this function adds the objects to the global finalization
2212 * list "list_fini" in the opposite order. The write lock must be
2213 * held when this function is called.
2216 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2220 if (obj->init_scanned || obj->init_done)
2222 obj->init_scanned = true;
2224 /* Recursively process the successor objects. */
2225 nobj = globallist_next(obj);
2226 if (nobj != NULL && obj != tail)
2227 initlist_add_objects(nobj, tail, list);
2229 /* Recursively process the needed objects. */
2230 if (obj->needed != NULL)
2231 initlist_add_neededs(obj->needed, list);
2232 if (obj->needed_filtees != NULL)
2233 initlist_add_neededs(obj->needed_filtees, list);
2234 if (obj->needed_aux_filtees != NULL)
2235 initlist_add_neededs(obj->needed_aux_filtees, list);
2237 /* Add the object to the init list. */
2238 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
2239 obj->init_array != (Elf_Addr)NULL)
2240 objlist_push_tail(list, obj);
2242 /* Add the object to the global fini list in the reverse order. */
2243 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2244 && !obj->on_fini_list) {
2245 objlist_push_head(&list_fini, obj);
2246 obj->on_fini_list = true;
2251 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2255 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2257 Needed_Entry *needed, *needed1;
2259 for (needed = n; needed != NULL; needed = needed->next) {
2260 if (needed->obj != NULL) {
2261 dlclose_locked(needed->obj, lockstate);
2265 for (needed = n; needed != NULL; needed = needed1) {
2266 needed1 = needed->next;
2272 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2275 free_needed_filtees(obj->needed_filtees, lockstate);
2276 obj->needed_filtees = NULL;
2277 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2278 obj->needed_aux_filtees = NULL;
2279 obj->filtees_loaded = false;
2283 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2284 RtldLockState *lockstate)
2287 for (; needed != NULL; needed = needed->next) {
2288 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2289 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2290 RTLD_LOCAL, lockstate);
2295 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2298 lock_restart_for_upgrade(lockstate);
2299 if (!obj->filtees_loaded) {
2300 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2301 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2302 obj->filtees_loaded = true;
2307 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2311 for (; needed != NULL; needed = needed->next) {
2312 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2313 flags & ~RTLD_LO_NOLOAD);
2314 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2321 * Given a shared object, traverse its list of needed objects, and load
2322 * each of them. Returns 0 on success. Generates an error message and
2323 * returns -1 on failure.
2326 load_needed_objects(Obj_Entry *first, int flags)
2330 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2333 if (process_needed(obj, obj->needed, flags) == -1)
2340 load_preload_objects(void)
2342 char *p = ld_preload;
2344 static const char delim[] = " \t:;";
2349 p += strspn(p, delim);
2350 while (*p != '\0') {
2351 size_t len = strcspn(p, delim);
2356 obj = load_object(p, -1, NULL, 0);
2358 return -1; /* XXX - cleanup */
2359 obj->z_interpose = true;
2362 p += strspn(p, delim);
2364 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2369 printable_path(const char *path)
2372 return (path == NULL ? "<unknown>" : path);
2376 * Load a shared object into memory, if it is not already loaded. The
2377 * object may be specified by name or by user-supplied file descriptor
2378 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2381 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2385 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2394 TAILQ_FOREACH(obj, &obj_list, next) {
2395 if (obj->marker || obj->doomed)
2397 if (object_match_name(obj, name))
2401 path = find_library(name, refobj, &fd);
2409 * search_library_pathfds() opens a fresh file descriptor for the
2410 * library, so there is no need to dup().
2412 } else if (fd_u == -1) {
2414 * If we didn't find a match by pathname, or the name is not
2415 * supplied, open the file and check again by device and inode.
2416 * This avoids false mismatches caused by multiple links or ".."
2419 * To avoid a race, we open the file and use fstat() rather than
2422 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2423 _rtld_error("Cannot open \"%s\"", path);
2428 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2430 _rtld_error("Cannot dup fd");
2435 if (fstat(fd, &sb) == -1) {
2436 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2441 TAILQ_FOREACH(obj, &obj_list, next) {
2442 if (obj->marker || obj->doomed)
2444 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2447 if (obj != NULL && name != NULL) {
2448 object_add_name(obj, name);
2453 if (flags & RTLD_LO_NOLOAD) {
2459 /* First use of this object, so we must map it in */
2460 obj = do_load_object(fd, name, path, &sb, flags);
2469 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2476 * but first, make sure that environment variables haven't been
2477 * used to circumvent the noexec flag on a filesystem.
2479 if (dangerous_ld_env) {
2480 if (fstatfs(fd, &fs) != 0) {
2481 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2484 if (fs.f_flags & MNT_NOEXEC) {
2485 _rtld_error("Cannot execute objects on %s", fs.f_mntonname);
2489 dbg("loading \"%s\"", printable_path(path));
2490 obj = map_object(fd, printable_path(path), sbp);
2495 * If DT_SONAME is present in the object, digest_dynamic2 already
2496 * added it to the object names.
2499 object_add_name(obj, name);
2501 digest_dynamic(obj, 0);
2502 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2503 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2504 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2506 dbg("refusing to load non-loadable \"%s\"", obj->path);
2507 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2508 munmap(obj->mapbase, obj->mapsize);
2513 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2514 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2517 linkmap_add(obj); /* for GDB & dlinfo() */
2518 max_stack_flags |= obj->stack_flags;
2520 dbg(" %p .. %p: %s", obj->mapbase,
2521 obj->mapbase + obj->mapsize - 1, obj->path);
2523 dbg(" WARNING: %s has impure text", obj->path);
2524 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2531 obj_from_addr(const void *addr)
2535 TAILQ_FOREACH(obj, &obj_list, next) {
2538 if (addr < (void *) obj->mapbase)
2540 if (addr < (void *)(obj->mapbase + obj->mapsize))
2549 Elf_Addr *preinit_addr;
2552 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2553 if (preinit_addr == NULL)
2556 for (index = 0; index < obj_main->preinit_array_num; index++) {
2557 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2558 dbg("calling preinit function for %s at %p", obj_main->path,
2559 (void *)preinit_addr[index]);
2560 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2561 0, 0, obj_main->path);
2562 call_init_pointer(obj_main, preinit_addr[index]);
2568 * Call the finalization functions for each of the objects in "list"
2569 * belonging to the DAG of "root" and referenced once. If NULL "root"
2570 * is specified, every finalization function will be called regardless
2571 * of the reference count and the list elements won't be freed. All of
2572 * the objects are expected to have non-NULL fini functions.
2575 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2579 Elf_Addr *fini_addr;
2582 assert(root == NULL || root->refcount == 1);
2585 root->doomed = true;
2588 * Preserve the current error message since a fini function might
2589 * call into the dynamic linker and overwrite it.
2591 saved_msg = errmsg_save();
2593 STAILQ_FOREACH(elm, list, link) {
2594 if (root != NULL && (elm->obj->refcount != 1 ||
2595 objlist_find(&root->dagmembers, elm->obj) == NULL))
2597 /* Remove object from fini list to prevent recursive invocation. */
2598 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2599 /* Ensure that new references cannot be acquired. */
2600 elm->obj->doomed = true;
2602 hold_object(elm->obj);
2603 lock_release(rtld_bind_lock, lockstate);
2605 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2606 * When this happens, DT_FINI_ARRAY is processed first.
2608 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2609 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2610 for (index = elm->obj->fini_array_num - 1; index >= 0;
2612 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2613 dbg("calling fini function for %s at %p",
2614 elm->obj->path, (void *)fini_addr[index]);
2615 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2616 (void *)fini_addr[index], 0, 0, elm->obj->path);
2617 call_initfini_pointer(elm->obj, fini_addr[index]);
2621 if (elm->obj->fini != (Elf_Addr)NULL) {
2622 dbg("calling fini function for %s at %p", elm->obj->path,
2623 (void *)elm->obj->fini);
2624 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2625 0, 0, elm->obj->path);
2626 call_initfini_pointer(elm->obj, elm->obj->fini);
2628 wlock_acquire(rtld_bind_lock, lockstate);
2629 unhold_object(elm->obj);
2630 /* No need to free anything if process is going down. */
2634 * We must restart the list traversal after every fini call
2635 * because a dlclose() call from the fini function or from
2636 * another thread might have modified the reference counts.
2640 } while (elm != NULL);
2641 errmsg_restore(saved_msg);
2645 * Call the initialization functions for each of the objects in
2646 * "list". All of the objects are expected to have non-NULL init
2650 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2655 Elf_Addr *init_addr;
2659 * Clean init_scanned flag so that objects can be rechecked and
2660 * possibly initialized earlier if any of vectors called below
2661 * cause the change by using dlopen.
2663 TAILQ_FOREACH(obj, &obj_list, next) {
2666 obj->init_scanned = false;
2670 * Preserve the current error message since an init function might
2671 * call into the dynamic linker and overwrite it.
2673 saved_msg = errmsg_save();
2674 STAILQ_FOREACH(elm, list, link) {
2675 if (elm->obj->init_done) /* Initialized early. */
2678 * Race: other thread might try to use this object before current
2679 * one completes the initialization. Not much can be done here
2680 * without better locking.
2682 elm->obj->init_done = true;
2683 hold_object(elm->obj);
2684 lock_release(rtld_bind_lock, lockstate);
2687 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2688 * When this happens, DT_INIT is processed first.
2690 if (elm->obj->init != (Elf_Addr)NULL) {
2691 dbg("calling init function for %s at %p", elm->obj->path,
2692 (void *)elm->obj->init);
2693 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2694 0, 0, elm->obj->path);
2695 call_initfini_pointer(elm->obj, elm->obj->init);
2697 init_addr = (Elf_Addr *)elm->obj->init_array;
2698 if (init_addr != NULL) {
2699 for (index = 0; index < elm->obj->init_array_num; index++) {
2700 if (init_addr[index] != 0 && init_addr[index] != 1) {
2701 dbg("calling init function for %s at %p", elm->obj->path,
2702 (void *)init_addr[index]);
2703 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2704 (void *)init_addr[index], 0, 0, elm->obj->path);
2705 call_init_pointer(elm->obj, init_addr[index]);
2709 wlock_acquire(rtld_bind_lock, lockstate);
2710 unhold_object(elm->obj);
2712 errmsg_restore(saved_msg);
2716 objlist_clear(Objlist *list)
2720 while (!STAILQ_EMPTY(list)) {
2721 elm = STAILQ_FIRST(list);
2722 STAILQ_REMOVE_HEAD(list, link);
2727 static Objlist_Entry *
2728 objlist_find(Objlist *list, const Obj_Entry *obj)
2732 STAILQ_FOREACH(elm, list, link)
2733 if (elm->obj == obj)
2739 objlist_init(Objlist *list)
2745 objlist_push_head(Objlist *list, Obj_Entry *obj)
2749 elm = NEW(Objlist_Entry);
2751 STAILQ_INSERT_HEAD(list, elm, link);
2755 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2759 elm = NEW(Objlist_Entry);
2761 STAILQ_INSERT_TAIL(list, elm, link);
2765 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2767 Objlist_Entry *elm, *listelm;
2769 STAILQ_FOREACH(listelm, list, link) {
2770 if (listelm->obj == listobj)
2773 elm = NEW(Objlist_Entry);
2775 if (listelm != NULL)
2776 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2778 STAILQ_INSERT_TAIL(list, elm, link);
2782 objlist_remove(Objlist *list, Obj_Entry *obj)
2786 if ((elm = objlist_find(list, obj)) != NULL) {
2787 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2793 * Relocate dag rooted in the specified object.
2794 * Returns 0 on success, or -1 on failure.
2798 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2799 int flags, RtldLockState *lockstate)
2805 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2806 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2815 * Prepare for, or clean after, relocating an object marked with
2816 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
2817 * segments are remapped read-write. After relocations are done, the
2818 * segment's permissions are returned back to the modes specified in
2819 * the phdrs. If any relocation happened, or always for wired
2820 * program, COW is triggered.
2823 reloc_textrel_prot(Obj_Entry *obj, bool before)
2830 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
2832 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
2834 base = obj->relocbase + trunc_page(ph->p_vaddr);
2835 sz = round_page(ph->p_vaddr + ph->p_filesz) -
2836 trunc_page(ph->p_vaddr);
2837 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0);
2838 if (mprotect(base, sz, prot) == -1) {
2839 _rtld_error("%s: Cannot write-%sable text segment: %s",
2840 obj->path, before ? "en" : "dis",
2841 rtld_strerror(errno));
2849 * Relocate single object.
2850 * Returns 0 on success, or -1 on failure.
2853 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2854 int flags, RtldLockState *lockstate)
2859 obj->relocated = true;
2861 dbg("relocating \"%s\"", obj->path);
2863 if (obj->symtab == NULL || obj->strtab == NULL ||
2864 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2865 _rtld_error("%s: Shared object has no run-time symbol table",
2870 /* There are relocations to the write-protected text segment. */
2871 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
2874 /* Process the non-PLT non-IFUNC relocations. */
2875 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2878 /* Re-protected the text segment. */
2879 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
2882 /* Set the special PLT or GOT entries. */
2885 /* Process the PLT relocations. */
2886 if (reloc_plt(obj) == -1)
2888 /* Relocate the jump slots if we are doing immediate binding. */
2889 if (obj->bind_now || bind_now) {
2890 if (reloc_jmpslots(obj, flags, lockstate) == -1 ||
2891 resolve_object_ifunc(obj, true, flags, lockstate) == -1)
2896 * Process the non-PLT IFUNC relocations. The relocations are
2897 * processed in two phases, because IFUNC resolvers may
2898 * reference other symbols, which must be readily processed
2899 * before resolvers are called.
2901 if (obj->non_plt_gnu_ifunc &&
2902 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
2905 if (!obj->mainprog && obj_enforce_relro(obj) == -1)
2909 * Set up the magic number and version in the Obj_Entry. These
2910 * were checked in the crt1.o from the original ElfKit, so we
2911 * set them for backward compatibility.
2913 obj->magic = RTLD_MAGIC;
2914 obj->version = RTLD_VERSION;
2920 * Relocate newly-loaded shared objects. The argument is a pointer to
2921 * the Obj_Entry for the first such object. All objects from the first
2922 * to the end of the list of objects are relocated. Returns 0 on success,
2926 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2927 int flags, RtldLockState *lockstate)
2932 for (error = 0, obj = first; obj != NULL;
2933 obj = TAILQ_NEXT(obj, next)) {
2936 error = relocate_object(obj, bind_now, rtldobj, flags,
2945 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2946 * referencing STT_GNU_IFUNC symbols is postponed till the other
2947 * relocations are done. The indirect functions specified as
2948 * ifunc are allowed to call other symbols, so we need to have
2949 * objects relocated before asking for resolution from indirects.
2951 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2952 * instead of the usual lazy handling of PLT slots. It is
2953 * consistent with how GNU does it.
2956 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2957 RtldLockState *lockstate)
2959 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2961 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2962 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2968 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2969 RtldLockState *lockstate)
2973 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2976 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2983 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2984 RtldLockState *lockstate)
2988 STAILQ_FOREACH(elm, list, link) {
2989 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2997 * Cleanup procedure. It will be called (by the atexit mechanism) just
2998 * before the process exits.
3003 RtldLockState lockstate;
3005 wlock_acquire(rtld_bind_lock, &lockstate);
3007 objlist_call_fini(&list_fini, NULL, &lockstate);
3008 /* No need to remove the items from the list, since we are exiting. */
3009 if (!libmap_disable)
3011 lock_release(rtld_bind_lock, &lockstate);
3015 * Iterate over a search path, translate each element, and invoke the
3016 * callback on the result.
3019 path_enumerate(const char *path, path_enum_proc callback,
3020 const char *refobj_path, void *arg)
3026 path += strspn(path, ":;");
3027 while (*path != '\0') {
3031 len = strcspn(path, ":;");
3032 trans = lm_findn(refobj_path, path, len);
3034 res = callback(trans, strlen(trans), arg);
3036 res = callback(path, len, arg);
3042 path += strspn(path, ":;");
3048 struct try_library_args {
3057 try_library_path(const char *dir, size_t dirlen, void *param)
3059 struct try_library_args *arg;
3063 if (*dir == '/' || trust) {
3066 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3069 pathname = arg->buffer;
3070 strncpy(pathname, dir, dirlen);
3071 pathname[dirlen] = '/';
3072 strcpy(pathname + dirlen + 1, arg->name);
3074 dbg(" Trying \"%s\"", pathname);
3075 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3077 dbg(" Opened \"%s\", fd %d", pathname, fd);
3078 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3079 strcpy(pathname, arg->buffer);
3083 dbg(" Failed to open \"%s\": %s",
3084 pathname, rtld_strerror(errno));
3091 search_library_path(const char *name, const char *path,
3092 const char *refobj_path, int *fdp)
3095 struct try_library_args arg;
3101 arg.namelen = strlen(name);
3102 arg.buffer = xmalloc(PATH_MAX);
3103 arg.buflen = PATH_MAX;
3106 p = path_enumerate(path, try_library_path, refobj_path, &arg);
3116 * Finds the library with the given name using the directory descriptors
3117 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3119 * Returns a freshly-opened close-on-exec file descriptor for the library,
3120 * or -1 if the library cannot be found.
3123 search_library_pathfds(const char *name, const char *path, int *fdp)
3125 char *envcopy, *fdstr, *found, *last_token;
3129 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3131 /* Don't load from user-specified libdirs into setuid binaries. */
3135 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3139 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3140 if (name[0] == '/') {
3141 dbg("Absolute path (%s) passed to %s", name, __func__);
3146 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3147 * copy of the path, as strtok_r rewrites separator tokens
3151 envcopy = xstrdup(path);
3152 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3153 fdstr = strtok_r(NULL, ":", &last_token)) {
3154 dirfd = parse_integer(fdstr);
3156 _rtld_error("failed to parse directory FD: '%s'",
3160 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3163 len = strlen(fdstr) + strlen(name) + 3;
3164 found = xmalloc(len);
3165 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
3166 _rtld_error("error generating '%d/%s'",
3170 dbg("open('%s') => %d", found, fd);
3181 dlclose(void *handle)
3183 RtldLockState lockstate;
3186 wlock_acquire(rtld_bind_lock, &lockstate);
3187 error = dlclose_locked(handle, &lockstate);
3188 lock_release(rtld_bind_lock, &lockstate);
3193 dlclose_locked(void *handle, RtldLockState *lockstate)
3197 root = dlcheck(handle);
3200 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3203 /* Unreference the object and its dependencies. */
3204 root->dl_refcount--;
3206 if (root->refcount == 1) {
3208 * The object will be no longer referenced, so we must unload it.
3209 * First, call the fini functions.
3211 objlist_call_fini(&list_fini, root, lockstate);
3215 /* Finish cleaning up the newly-unreferenced objects. */
3216 GDB_STATE(RT_DELETE,&root->linkmap);
3217 unload_object(root, lockstate);
3218 GDB_STATE(RT_CONSISTENT,NULL);
3222 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3229 char *msg = error_message;
3230 error_message = NULL;
3235 * This function is deprecated and has no effect.
3238 dllockinit(void *context,
3239 void *(*_lock_create)(void *context) __unused,
3240 void (*_rlock_acquire)(void *lock) __unused,
3241 void (*_wlock_acquire)(void *lock) __unused,
3242 void (*_lock_release)(void *lock) __unused,
3243 void (*_lock_destroy)(void *lock) __unused,
3244 void (*context_destroy)(void *context))
3246 static void *cur_context;
3247 static void (*cur_context_destroy)(void *);
3249 /* Just destroy the context from the previous call, if necessary. */
3250 if (cur_context_destroy != NULL)
3251 cur_context_destroy(cur_context);
3252 cur_context = context;
3253 cur_context_destroy = context_destroy;
3257 dlopen(const char *name, int mode)
3260 return (rtld_dlopen(name, -1, mode));
3264 fdlopen(int fd, int mode)
3267 return (rtld_dlopen(NULL, fd, mode));
3271 rtld_dlopen(const char *name, int fd, int mode)
3273 RtldLockState lockstate;
3276 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3277 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3278 if (ld_tracing != NULL) {
3279 rlock_acquire(rtld_bind_lock, &lockstate);
3280 if (sigsetjmp(lockstate.env, 0) != 0)
3281 lock_upgrade(rtld_bind_lock, &lockstate);
3282 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate));
3283 lock_release(rtld_bind_lock, &lockstate);
3285 lo_flags = RTLD_LO_DLOPEN;
3286 if (mode & RTLD_NODELETE)
3287 lo_flags |= RTLD_LO_NODELETE;
3288 if (mode & RTLD_NOLOAD)
3289 lo_flags |= RTLD_LO_NOLOAD;
3290 if (ld_tracing != NULL)
3291 lo_flags |= RTLD_LO_TRACE;
3293 return (dlopen_object(name, fd, obj_main, lo_flags,
3294 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3298 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3303 if (obj->refcount == 0)
3304 unload_object(obj, lockstate);
3308 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3309 int mode, RtldLockState *lockstate)
3311 Obj_Entry *old_obj_tail;
3314 RtldLockState mlockstate;
3317 objlist_init(&initlist);
3319 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3320 wlock_acquire(rtld_bind_lock, &mlockstate);
3321 lockstate = &mlockstate;
3323 GDB_STATE(RT_ADD,NULL);
3325 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
3327 if (name == NULL && fd == -1) {
3331 obj = load_object(name, fd, refobj, lo_flags);
3336 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3337 objlist_push_tail(&list_global, obj);
3338 if (globallist_next(old_obj_tail) != NULL) {
3339 /* We loaded something new. */
3340 assert(globallist_next(old_obj_tail) == obj);
3341 result = load_needed_objects(obj,
3342 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
3346 result = rtld_verify_versions(&obj->dagmembers);
3347 if (result != -1 && ld_tracing)
3349 if (result == -1 || relocate_object_dag(obj,
3350 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3351 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3353 dlopen_cleanup(obj, lockstate);
3355 } else if (lo_flags & RTLD_LO_EARLY) {
3357 * Do not call the init functions for early loaded
3358 * filtees. The image is still not initialized enough
3361 * Our object is found by the global object list and
3362 * will be ordered among all init calls done right
3363 * before transferring control to main.
3366 /* Make list of init functions to call. */
3367 initlist_add_objects(obj, obj, &initlist);
3370 * Process all no_delete or global objects here, given
3371 * them own DAGs to prevent their dependencies from being
3372 * unloaded. This has to be done after we have loaded all
3373 * of the dependencies, so that we do not miss any.
3379 * Bump the reference counts for objects on this DAG. If
3380 * this is the first dlopen() call for the object that was
3381 * already loaded as a dependency, initialize the dag
3387 if ((lo_flags & RTLD_LO_TRACE) != 0)
3390 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3391 obj->z_nodelete) && !obj->ref_nodel) {
3392 dbg("obj %s nodelete", obj->path);
3394 obj->z_nodelete = obj->ref_nodel = true;
3398 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3400 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3402 if (!(lo_flags & RTLD_LO_EARLY)) {
3403 map_stacks_exec(lockstate);
3406 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3407 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3409 objlist_clear(&initlist);
3410 dlopen_cleanup(obj, lockstate);
3411 if (lockstate == &mlockstate)
3412 lock_release(rtld_bind_lock, lockstate);
3416 if (!(lo_flags & RTLD_LO_EARLY)) {
3417 /* Call the init functions. */
3418 objlist_call_init(&initlist, lockstate);
3420 objlist_clear(&initlist);
3421 if (lockstate == &mlockstate)
3422 lock_release(rtld_bind_lock, lockstate);
3425 trace_loaded_objects(obj);
3426 if (lockstate == &mlockstate)
3427 lock_release(rtld_bind_lock, lockstate);
3432 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3436 const Obj_Entry *obj, *defobj;
3439 RtldLockState lockstate;
3446 symlook_init(&req, name);
3448 req.flags = flags | SYMLOOK_IN_PLT;
3449 req.lockstate = &lockstate;
3451 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3452 rlock_acquire(rtld_bind_lock, &lockstate);
3453 if (sigsetjmp(lockstate.env, 0) != 0)
3454 lock_upgrade(rtld_bind_lock, &lockstate);
3455 if (handle == NULL || handle == RTLD_NEXT ||
3456 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3458 if ((obj = obj_from_addr(retaddr)) == NULL) {
3459 _rtld_error("Cannot determine caller's shared object");
3460 lock_release(rtld_bind_lock, &lockstate);
3461 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3464 if (handle == NULL) { /* Just the caller's shared object. */
3465 res = symlook_obj(&req, obj);
3468 defobj = req.defobj_out;
3470 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3471 handle == RTLD_SELF) { /* ... caller included */
3472 if (handle == RTLD_NEXT)
3473 obj = globallist_next(obj);
3474 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3477 res = symlook_obj(&req, obj);
3480 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3482 defobj = req.defobj_out;
3483 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3489 * Search the dynamic linker itself, and possibly resolve the
3490 * symbol from there. This is how the application links to
3491 * dynamic linker services such as dlopen.
3493 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3494 res = symlook_obj(&req, &obj_rtld);
3497 defobj = req.defobj_out;
3501 assert(handle == RTLD_DEFAULT);
3502 res = symlook_default(&req, obj);
3504 defobj = req.defobj_out;
3509 if ((obj = dlcheck(handle)) == NULL) {
3510 lock_release(rtld_bind_lock, &lockstate);
3511 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3515 donelist_init(&donelist);
3516 if (obj->mainprog) {
3517 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3518 res = symlook_global(&req, &donelist);
3521 defobj = req.defobj_out;
3524 * Search the dynamic linker itself, and possibly resolve the
3525 * symbol from there. This is how the application links to
3526 * dynamic linker services such as dlopen.
3528 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3529 res = symlook_obj(&req, &obj_rtld);
3532 defobj = req.defobj_out;
3537 /* Search the whole DAG rooted at the given object. */
3538 res = symlook_list(&req, &obj->dagmembers, &donelist);
3541 defobj = req.defobj_out;
3547 lock_release(rtld_bind_lock, &lockstate);
3550 * The value required by the caller is derived from the value
3551 * of the symbol. this is simply the relocated value of the
3554 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3555 sym = make_function_pointer(def, defobj);
3556 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3557 sym = rtld_resolve_ifunc(defobj, def);
3558 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3559 ti.ti_module = defobj->tlsindex;
3560 ti.ti_offset = def->st_value;
3561 sym = __tls_get_addr(&ti);
3563 sym = defobj->relocbase + def->st_value;
3564 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3568 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
3569 ve != NULL ? ve->name : "");
3570 lock_release(rtld_bind_lock, &lockstate);
3571 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3576 dlsym(void *handle, const char *name)
3578 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3583 dlfunc(void *handle, const char *name)
3590 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3596 dlvsym(void *handle, const char *name, const char *version)
3600 ventry.name = version;
3602 ventry.hash = elf_hash(version);
3604 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3609 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3611 const Obj_Entry *obj;
3612 RtldLockState lockstate;
3614 rlock_acquire(rtld_bind_lock, &lockstate);
3615 obj = obj_from_addr(addr);
3617 _rtld_error("No shared object contains address");
3618 lock_release(rtld_bind_lock, &lockstate);
3621 rtld_fill_dl_phdr_info(obj, phdr_info);
3622 lock_release(rtld_bind_lock, &lockstate);
3627 dladdr(const void *addr, Dl_info *info)
3629 const Obj_Entry *obj;
3632 unsigned long symoffset;
3633 RtldLockState lockstate;
3635 rlock_acquire(rtld_bind_lock, &lockstate);
3636 obj = obj_from_addr(addr);
3638 _rtld_error("No shared object contains address");
3639 lock_release(rtld_bind_lock, &lockstate);
3642 info->dli_fname = obj->path;
3643 info->dli_fbase = obj->mapbase;
3644 info->dli_saddr = (void *)0;
3645 info->dli_sname = NULL;
3648 * Walk the symbol list looking for the symbol whose address is
3649 * closest to the address sent in.
3651 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3652 def = obj->symtab + symoffset;
3655 * For skip the symbol if st_shndx is either SHN_UNDEF or
3658 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3662 * If the symbol is greater than the specified address, or if it
3663 * is further away from addr than the current nearest symbol,
3666 symbol_addr = obj->relocbase + def->st_value;
3667 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3670 /* Update our idea of the nearest symbol. */
3671 info->dli_sname = obj->strtab + def->st_name;
3672 info->dli_saddr = symbol_addr;
3675 if (info->dli_saddr == addr)
3678 lock_release(rtld_bind_lock, &lockstate);
3683 dlinfo(void *handle, int request, void *p)
3685 const Obj_Entry *obj;
3686 RtldLockState lockstate;
3689 rlock_acquire(rtld_bind_lock, &lockstate);
3691 if (handle == NULL || handle == RTLD_SELF) {
3694 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3695 if ((obj = obj_from_addr(retaddr)) == NULL)
3696 _rtld_error("Cannot determine caller's shared object");
3698 obj = dlcheck(handle);
3701 lock_release(rtld_bind_lock, &lockstate);
3707 case RTLD_DI_LINKMAP:
3708 *((struct link_map const **)p) = &obj->linkmap;
3710 case RTLD_DI_ORIGIN:
3711 error = rtld_dirname(obj->path, p);
3714 case RTLD_DI_SERINFOSIZE:
3715 case RTLD_DI_SERINFO:
3716 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3720 _rtld_error("Invalid request %d passed to dlinfo()", request);
3724 lock_release(rtld_bind_lock, &lockstate);
3730 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3733 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3734 phdr_info->dlpi_name = obj->path;
3735 phdr_info->dlpi_phdr = obj->phdr;
3736 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3737 phdr_info->dlpi_tls_modid = obj->tlsindex;
3738 phdr_info->dlpi_tls_data = obj->tlsinit;
3739 phdr_info->dlpi_adds = obj_loads;
3740 phdr_info->dlpi_subs = obj_loads - obj_count;
3744 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3746 struct dl_phdr_info phdr_info;
3747 Obj_Entry *obj, marker;
3748 RtldLockState bind_lockstate, phdr_lockstate;
3751 init_marker(&marker);
3754 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3755 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3756 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
3757 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
3758 rtld_fill_dl_phdr_info(obj, &phdr_info);
3760 lock_release(rtld_bind_lock, &bind_lockstate);
3762 error = callback(&phdr_info, sizeof phdr_info, param);
3764 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3766 obj = globallist_next(&marker);
3767 TAILQ_REMOVE(&obj_list, &marker, next);
3769 lock_release(rtld_bind_lock, &bind_lockstate);
3770 lock_release(rtld_phdr_lock, &phdr_lockstate);
3776 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3777 lock_release(rtld_bind_lock, &bind_lockstate);
3778 error = callback(&phdr_info, sizeof(phdr_info), param);
3780 lock_release(rtld_phdr_lock, &phdr_lockstate);
3785 fill_search_info(const char *dir, size_t dirlen, void *param)
3787 struct fill_search_info_args *arg;
3791 if (arg->request == RTLD_DI_SERINFOSIZE) {
3792 arg->serinfo->dls_cnt ++;
3793 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3795 struct dl_serpath *s_entry;
3797 s_entry = arg->serpath;
3798 s_entry->dls_name = arg->strspace;
3799 s_entry->dls_flags = arg->flags;
3801 strncpy(arg->strspace, dir, dirlen);
3802 arg->strspace[dirlen] = '\0';
3804 arg->strspace += dirlen + 1;
3812 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3814 struct dl_serinfo _info;
3815 struct fill_search_info_args args;
3817 args.request = RTLD_DI_SERINFOSIZE;
3818 args.serinfo = &_info;
3820 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3823 path_enumerate(obj->rpath, fill_search_info, NULL, &args);
3824 path_enumerate(ld_library_path, fill_search_info, NULL, &args);
3825 path_enumerate(obj->runpath, fill_search_info, NULL, &args);
3826 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args);
3827 if (!obj->z_nodeflib)
3828 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args);
3831 if (request == RTLD_DI_SERINFOSIZE) {
3832 info->dls_size = _info.dls_size;
3833 info->dls_cnt = _info.dls_cnt;
3837 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3838 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3842 args.request = RTLD_DI_SERINFO;
3843 args.serinfo = info;
3844 args.serpath = &info->dls_serpath[0];
3845 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3847 args.flags = LA_SER_RUNPATH;
3848 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL)
3851 args.flags = LA_SER_LIBPATH;
3852 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL)
3855 args.flags = LA_SER_RUNPATH;
3856 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL)
3859 args.flags = LA_SER_CONFIG;
3860 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args)
3864 args.flags = LA_SER_DEFAULT;
3865 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path,
3866 fill_search_info, NULL, &args) != NULL)
3872 rtld_dirname(const char *path, char *bname)
3876 /* Empty or NULL string gets treated as "." */
3877 if (path == NULL || *path == '\0') {
3883 /* Strip trailing slashes */
3884 endp = path + strlen(path) - 1;
3885 while (endp > path && *endp == '/')
3888 /* Find the start of the dir */
3889 while (endp > path && *endp != '/')
3892 /* Either the dir is "/" or there are no slashes */
3894 bname[0] = *endp == '/' ? '/' : '.';
3900 } while (endp > path && *endp == '/');
3903 if (endp - path + 2 > PATH_MAX)
3905 _rtld_error("Filename is too long: %s", path);
3909 strncpy(bname, path, endp - path + 1);
3910 bname[endp - path + 1] = '\0';
3915 rtld_dirname_abs(const char *path, char *base)
3919 if (realpath(path, base) == NULL)
3921 dbg("%s -> %s", path, base);
3922 last = strrchr(base, '/');
3931 linkmap_add(Obj_Entry *obj)
3933 struct link_map *l = &obj->linkmap;
3934 struct link_map *prev;
3936 obj->linkmap.l_name = obj->path;
3937 obj->linkmap.l_addr = obj->mapbase;
3938 obj->linkmap.l_ld = obj->dynamic;
3940 /* GDB needs load offset on MIPS to use the symbols */
3941 obj->linkmap.l_offs = obj->relocbase;
3944 if (r_debug.r_map == NULL) {
3950 * Scan to the end of the list, but not past the entry for the
3951 * dynamic linker, which we want to keep at the very end.
3953 for (prev = r_debug.r_map;
3954 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3955 prev = prev->l_next)
3958 /* Link in the new entry. */
3960 l->l_next = prev->l_next;
3961 if (l->l_next != NULL)
3962 l->l_next->l_prev = l;
3967 linkmap_delete(Obj_Entry *obj)
3969 struct link_map *l = &obj->linkmap;
3971 if (l->l_prev == NULL) {
3972 if ((r_debug.r_map = l->l_next) != NULL)
3973 l->l_next->l_prev = NULL;
3977 if ((l->l_prev->l_next = l->l_next) != NULL)
3978 l->l_next->l_prev = l->l_prev;
3982 * Function for the debugger to set a breakpoint on to gain control.
3984 * The two parameters allow the debugger to easily find and determine
3985 * what the runtime loader is doing and to whom it is doing it.
3987 * When the loadhook trap is hit (r_debug_state, set at program
3988 * initialization), the arguments can be found on the stack:
3990 * +8 struct link_map *m
3991 * +4 struct r_debug *rd
3995 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused)
3998 * The following is a hack to force the compiler to emit calls to
3999 * this function, even when optimizing. If the function is empty,
4000 * the compiler is not obliged to emit any code for calls to it,
4001 * even when marked __noinline. However, gdb depends on those
4004 __compiler_membar();
4008 * A function called after init routines have completed. This can be used to
4009 * break before a program's entry routine is called, and can be used when
4010 * main is not available in the symbol table.
4013 _r_debug_postinit(struct link_map *m __unused)
4016 /* See r_debug_state(). */
4017 __compiler_membar();
4021 release_object(Obj_Entry *obj)
4024 if (obj->holdcount > 0) {
4025 obj->unholdfree = true;
4028 munmap(obj->mapbase, obj->mapsize);
4029 linkmap_delete(obj);
4034 * Get address of the pointer variable in the main program.
4035 * Prefer non-weak symbol over the weak one.
4037 static const void **
4038 get_program_var_addr(const char *name, RtldLockState *lockstate)
4043 symlook_init(&req, name);
4044 req.lockstate = lockstate;
4045 donelist_init(&donelist);
4046 if (symlook_global(&req, &donelist) != 0)
4048 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4049 return ((const void **)make_function_pointer(req.sym_out,
4051 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4052 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
4054 return ((const void **)(req.defobj_out->relocbase +
4055 req.sym_out->st_value));
4059 * Set a pointer variable in the main program to the given value. This
4060 * is used to set key variables such as "environ" before any of the
4061 * init functions are called.
4064 set_program_var(const char *name, const void *value)
4068 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4069 dbg("\"%s\": *%p <-- %p", name, addr, value);
4075 * Search the global objects, including dependencies and main object,
4076 * for the given symbol.
4079 symlook_global(SymLook *req, DoneList *donelist)
4082 const Objlist_Entry *elm;
4085 symlook_init_from_req(&req1, req);
4087 /* Search all objects loaded at program start up. */
4088 if (req->defobj_out == NULL ||
4089 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4090 res = symlook_list(&req1, &list_main, donelist);
4091 if (res == 0 && (req->defobj_out == NULL ||
4092 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4093 req->sym_out = req1.sym_out;
4094 req->defobj_out = req1.defobj_out;
4095 assert(req->defobj_out != NULL);
4099 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4100 STAILQ_FOREACH(elm, &list_global, link) {
4101 if (req->defobj_out != NULL &&
4102 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4104 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4105 if (res == 0 && (req->defobj_out == NULL ||
4106 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4107 req->sym_out = req1.sym_out;
4108 req->defobj_out = req1.defobj_out;
4109 assert(req->defobj_out != NULL);
4113 return (req->sym_out != NULL ? 0 : ESRCH);
4117 * Given a symbol name in a referencing object, find the corresponding
4118 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4119 * no definition was found. Returns a pointer to the Obj_Entry of the
4120 * defining object via the reference parameter DEFOBJ_OUT.
4123 symlook_default(SymLook *req, const Obj_Entry *refobj)
4126 const Objlist_Entry *elm;
4130 donelist_init(&donelist);
4131 symlook_init_from_req(&req1, req);
4134 * Look first in the referencing object if linked symbolically,
4135 * and similarly handle protected symbols.
4137 res = symlook_obj(&req1, refobj);
4138 if (res == 0 && (refobj->symbolic ||
4139 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) {
4140 req->sym_out = req1.sym_out;
4141 req->defobj_out = req1.defobj_out;
4142 assert(req->defobj_out != NULL);
4144 if (refobj->symbolic || req->defobj_out != NULL)
4145 donelist_check(&donelist, refobj);
4147 symlook_global(req, &donelist);
4149 /* Search all dlopened DAGs containing the referencing object. */
4150 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4151 if (req->sym_out != NULL &&
4152 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4154 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4155 if (res == 0 && (req->sym_out == NULL ||
4156 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4157 req->sym_out = req1.sym_out;
4158 req->defobj_out = req1.defobj_out;
4159 assert(req->defobj_out != NULL);
4164 * Search the dynamic linker itself, and possibly resolve the
4165 * symbol from there. This is how the application links to
4166 * dynamic linker services such as dlopen.
4168 if (req->sym_out == NULL ||
4169 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4170 res = symlook_obj(&req1, &obj_rtld);
4172 req->sym_out = req1.sym_out;
4173 req->defobj_out = req1.defobj_out;
4174 assert(req->defobj_out != NULL);
4178 return (req->sym_out != NULL ? 0 : ESRCH);
4182 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4185 const Obj_Entry *defobj;
4186 const Objlist_Entry *elm;
4192 STAILQ_FOREACH(elm, objlist, link) {
4193 if (donelist_check(dlp, elm->obj))
4195 symlook_init_from_req(&req1, req);
4196 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4197 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4199 defobj = req1.defobj_out;
4200 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4207 req->defobj_out = defobj;
4214 * Search the chain of DAGS cointed to by the given Needed_Entry
4215 * for a symbol of the given name. Each DAG is scanned completely
4216 * before advancing to the next one. Returns a pointer to the symbol,
4217 * or NULL if no definition was found.
4220 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4223 const Needed_Entry *n;
4224 const Obj_Entry *defobj;
4230 symlook_init_from_req(&req1, req);
4231 for (n = needed; n != NULL; n = n->next) {
4232 if (n->obj == NULL ||
4233 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
4235 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4237 defobj = req1.defobj_out;
4238 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4244 req->defobj_out = defobj;
4251 * Search the symbol table of a single shared object for a symbol of
4252 * the given name and version, if requested. Returns a pointer to the
4253 * symbol, or NULL if no definition was found. If the object is
4254 * filter, return filtered symbol from filtee.
4256 * The symbol's hash value is passed in for efficiency reasons; that
4257 * eliminates many recomputations of the hash value.
4260 symlook_obj(SymLook *req, const Obj_Entry *obj)
4264 int flags, res, mres;
4267 * If there is at least one valid hash at this point, we prefer to
4268 * use the faster GNU version if available.
4270 if (obj->valid_hash_gnu)
4271 mres = symlook_obj1_gnu(req, obj);
4272 else if (obj->valid_hash_sysv)
4273 mres = symlook_obj1_sysv(req, obj);
4278 if (obj->needed_filtees != NULL) {
4279 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4280 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4281 donelist_init(&donelist);
4282 symlook_init_from_req(&req1, req);
4283 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
4285 req->sym_out = req1.sym_out;
4286 req->defobj_out = req1.defobj_out;
4290 if (obj->needed_aux_filtees != NULL) {
4291 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4292 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4293 donelist_init(&donelist);
4294 symlook_init_from_req(&req1, req);
4295 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
4297 req->sym_out = req1.sym_out;
4298 req->defobj_out = req1.defobj_out;
4306 /* Symbol match routine common to both hash functions */
4308 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4309 const unsigned long symnum)
4312 const Elf_Sym *symp;
4315 symp = obj->symtab + symnum;
4316 strp = obj->strtab + symp->st_name;
4318 switch (ELF_ST_TYPE(symp->st_info)) {
4324 if (symp->st_value == 0)
4328 if (symp->st_shndx != SHN_UNDEF)
4331 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4332 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4339 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4342 if (req->ventry == NULL) {
4343 if (obj->versyms != NULL) {
4344 verndx = VER_NDX(obj->versyms[symnum]);
4345 if (verndx > obj->vernum) {
4347 "%s: symbol %s references wrong version %d",
4348 obj->path, obj->strtab + symnum, verndx);
4352 * If we are not called from dlsym (i.e. this
4353 * is a normal relocation from unversioned
4354 * binary), accept the symbol immediately if
4355 * it happens to have first version after this
4356 * shared object became versioned. Otherwise,
4357 * if symbol is versioned and not hidden,
4358 * remember it. If it is the only symbol with
4359 * this name exported by the shared object, it
4360 * will be returned as a match by the calling
4361 * function. If symbol is global (verndx < 2)
4362 * accept it unconditionally.
4364 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4365 verndx == VER_NDX_GIVEN) {
4366 result->sym_out = symp;
4369 else if (verndx >= VER_NDX_GIVEN) {
4370 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4372 if (result->vsymp == NULL)
4373 result->vsymp = symp;
4379 result->sym_out = symp;
4382 if (obj->versyms == NULL) {
4383 if (object_match_name(obj, req->ventry->name)) {
4384 _rtld_error("%s: object %s should provide version %s "
4385 "for symbol %s", obj_rtld.path, obj->path,
4386 req->ventry->name, obj->strtab + symnum);
4390 verndx = VER_NDX(obj->versyms[symnum]);
4391 if (verndx > obj->vernum) {
4392 _rtld_error("%s: symbol %s references wrong version %d",
4393 obj->path, obj->strtab + symnum, verndx);
4396 if (obj->vertab[verndx].hash != req->ventry->hash ||
4397 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4399 * Version does not match. Look if this is a
4400 * global symbol and if it is not hidden. If
4401 * global symbol (verndx < 2) is available,
4402 * use it. Do not return symbol if we are
4403 * called by dlvsym, because dlvsym looks for
4404 * a specific version and default one is not
4405 * what dlvsym wants.
4407 if ((req->flags & SYMLOOK_DLSYM) ||
4408 (verndx >= VER_NDX_GIVEN) ||
4409 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4413 result->sym_out = symp;
4418 * Search for symbol using SysV hash function.
4419 * obj->buckets is known not to be NULL at this point; the test for this was
4420 * performed with the obj->valid_hash_sysv assignment.
4423 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4425 unsigned long symnum;
4426 Sym_Match_Result matchres;
4428 matchres.sym_out = NULL;
4429 matchres.vsymp = NULL;
4430 matchres.vcount = 0;
4432 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4433 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4434 if (symnum >= obj->nchains)
4435 return (ESRCH); /* Bad object */
4437 if (matched_symbol(req, obj, &matchres, symnum)) {
4438 req->sym_out = matchres.sym_out;
4439 req->defobj_out = obj;
4443 if (matchres.vcount == 1) {
4444 req->sym_out = matchres.vsymp;
4445 req->defobj_out = obj;
4451 /* Search for symbol using GNU hash function */
4453 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4455 Elf_Addr bloom_word;
4456 const Elf32_Word *hashval;
4458 Sym_Match_Result matchres;
4459 unsigned int h1, h2;
4460 unsigned long symnum;
4462 matchres.sym_out = NULL;
4463 matchres.vsymp = NULL;
4464 matchres.vcount = 0;
4466 /* Pick right bitmask word from Bloom filter array */
4467 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4468 obj->maskwords_bm_gnu];
4470 /* Calculate modulus word size of gnu hash and its derivative */
4471 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4472 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4474 /* Filter out the "definitely not in set" queries */
4475 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4478 /* Locate hash chain and corresponding value element*/
4479 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4482 hashval = &obj->chain_zero_gnu[bucket];
4484 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4485 symnum = hashval - obj->chain_zero_gnu;
4486 if (matched_symbol(req, obj, &matchres, symnum)) {
4487 req->sym_out = matchres.sym_out;
4488 req->defobj_out = obj;
4492 } while ((*hashval++ & 1) == 0);
4493 if (matchres.vcount == 1) {
4494 req->sym_out = matchres.vsymp;
4495 req->defobj_out = obj;
4502 trace_loaded_objects(Obj_Entry *obj)
4504 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4507 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL)
4510 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL)
4511 fmt1 = "\t%o => %p (%x)\n";
4513 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL)
4514 fmt2 = "\t%o (%x)\n";
4516 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL"));
4518 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4519 Needed_Entry *needed;
4520 const char *name, *path;
4525 if (list_containers && obj->needed != NULL)
4526 rtld_printf("%s:\n", obj->path);
4527 for (needed = obj->needed; needed; needed = needed->next) {
4528 if (needed->obj != NULL) {
4529 if (needed->obj->traced && !list_containers)
4531 needed->obj->traced = true;
4532 path = needed->obj->path;
4536 name = obj->strtab + needed->name;
4537 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4539 fmt = is_lib ? fmt1 : fmt2;
4540 while ((c = *fmt++) != '\0') {
4566 rtld_putstr(main_local);
4569 rtld_putstr(obj_main->path);
4576 rtld_printf("%d", sodp->sod_major);
4579 rtld_printf("%d", sodp->sod_minor);
4586 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4599 * Unload a dlopened object and its dependencies from memory and from
4600 * our data structures. It is assumed that the DAG rooted in the
4601 * object has already been unreferenced, and that the object has a
4602 * reference count of 0.
4605 unload_object(Obj_Entry *root, RtldLockState *lockstate)
4607 Obj_Entry marker, *obj, *next;
4609 assert(root->refcount == 0);
4612 * Pass over the DAG removing unreferenced objects from
4613 * appropriate lists.
4615 unlink_object(root);
4617 /* Unmap all objects that are no longer referenced. */
4618 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
4619 next = TAILQ_NEXT(obj, next);
4620 if (obj->marker || obj->refcount != 0)
4622 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
4623 obj->mapsize, 0, obj->path);
4624 dbg("unloading \"%s\"", obj->path);
4626 * Unlink the object now to prevent new references from
4627 * being acquired while the bind lock is dropped in
4628 * recursive dlclose() invocations.
4630 TAILQ_REMOVE(&obj_list, obj, next);
4633 if (obj->filtees_loaded) {
4635 init_marker(&marker);
4636 TAILQ_INSERT_BEFORE(next, &marker, next);
4637 unload_filtees(obj, lockstate);
4638 next = TAILQ_NEXT(&marker, next);
4639 TAILQ_REMOVE(&obj_list, &marker, next);
4641 unload_filtees(obj, lockstate);
4643 release_object(obj);
4648 unlink_object(Obj_Entry *root)
4652 if (root->refcount == 0) {
4653 /* Remove the object from the RTLD_GLOBAL list. */
4654 objlist_remove(&list_global, root);
4656 /* Remove the object from all objects' DAG lists. */
4657 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4658 objlist_remove(&elm->obj->dldags, root);
4659 if (elm->obj != root)
4660 unlink_object(elm->obj);
4666 ref_dag(Obj_Entry *root)
4670 assert(root->dag_inited);
4671 STAILQ_FOREACH(elm, &root->dagmembers, link)
4672 elm->obj->refcount++;
4676 unref_dag(Obj_Entry *root)
4680 assert(root->dag_inited);
4681 STAILQ_FOREACH(elm, &root->dagmembers, link)
4682 elm->obj->refcount--;
4686 * Common code for MD __tls_get_addr().
4688 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4690 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4692 Elf_Addr *newdtv, *dtv;
4693 RtldLockState lockstate;
4697 /* Check dtv generation in case new modules have arrived */
4698 if (dtv[0] != tls_dtv_generation) {
4699 wlock_acquire(rtld_bind_lock, &lockstate);
4700 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4702 if (to_copy > tls_max_index)
4703 to_copy = tls_max_index;
4704 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4705 newdtv[0] = tls_dtv_generation;
4706 newdtv[1] = tls_max_index;
4708 lock_release(rtld_bind_lock, &lockstate);
4709 dtv = *dtvp = newdtv;
4712 /* Dynamically allocate module TLS if necessary */
4713 if (dtv[index + 1] == 0) {
4714 /* Signal safe, wlock will block out signals. */
4715 wlock_acquire(rtld_bind_lock, &lockstate);
4716 if (!dtv[index + 1])
4717 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4718 lock_release(rtld_bind_lock, &lockstate);
4720 return ((void *)(dtv[index + 1] + offset));
4724 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4729 /* Check dtv generation in case new modules have arrived */
4730 if (__predict_true(dtv[0] == tls_dtv_generation &&
4731 dtv[index + 1] != 0))
4732 return ((void *)(dtv[index + 1] + offset));
4733 return (tls_get_addr_slow(dtvp, index, offset));
4736 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
4737 defined(__powerpc__) || defined(__riscv)
4740 * Return pointer to allocated TLS block
4743 get_tls_block_ptr(void *tcb, size_t tcbsize)
4745 size_t extra_size, post_size, pre_size, tls_block_size;
4746 size_t tls_init_align;
4748 tls_init_align = MAX(obj_main->tlsalign, 1);
4750 /* Compute fragments sizes. */
4751 extra_size = tcbsize - TLS_TCB_SIZE;
4752 post_size = calculate_tls_post_size(tls_init_align);
4753 tls_block_size = tcbsize + post_size;
4754 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4756 return ((char *)tcb - pre_size - extra_size);
4760 * Allocate Static TLS using the Variant I method.
4762 * For details on the layout, see lib/libc/gen/tls.c.
4764 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as
4765 * it is based on tls_last_offset, and TLS offsets here are really TCB
4766 * offsets, whereas libc's tls_static_space is just the executable's static
4770 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4774 Elf_Addr *dtv, **tcb;
4777 size_t extra_size, maxalign, post_size, pre_size, tls_block_size;
4778 size_t tls_init_align;
4780 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4783 assert(tcbsize >= TLS_TCB_SIZE);
4784 maxalign = MAX(tcbalign, tls_static_max_align);
4785 tls_init_align = MAX(obj_main->tlsalign, 1);
4787 /* Compute fragmets sizes. */
4788 extra_size = tcbsize - TLS_TCB_SIZE;
4789 post_size = calculate_tls_post_size(tls_init_align);
4790 tls_block_size = tcbsize + post_size;
4791 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4792 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size;
4794 /* Allocate whole TLS block */
4795 tls_block = malloc_aligned(tls_block_size, maxalign);
4796 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size);
4798 if (oldtcb != NULL) {
4799 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize),
4801 free_aligned(get_tls_block_ptr(oldtcb, tcbsize));
4803 /* Adjust the DTV. */
4805 for (i = 0; i < dtv[1]; i++) {
4806 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4807 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4808 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb;
4812 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4814 dtv[0] = tls_dtv_generation;
4815 dtv[1] = tls_max_index;
4817 for (obj = globallist_curr(objs); obj != NULL;
4818 obj = globallist_next(obj)) {
4819 if (obj->tlsoffset > 0) {
4820 addr = (Elf_Addr)tcb + obj->tlsoffset;
4821 if (obj->tlsinitsize > 0)
4822 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4823 if (obj->tlssize > obj->tlsinitsize)
4824 memset((void*)(addr + obj->tlsinitsize), 0,
4825 obj->tlssize - obj->tlsinitsize);
4826 dtv[obj->tlsindex + 1] = addr;
4835 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
4838 Elf_Addr tlsstart, tlsend;
4840 size_t dtvsize, i, tls_init_align;
4842 assert(tcbsize >= TLS_TCB_SIZE);
4843 tls_init_align = MAX(obj_main->tlsalign, 1);
4845 /* Compute fragments sizes. */
4846 post_size = calculate_tls_post_size(tls_init_align);
4848 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size;
4849 tlsend = (Elf_Addr)tcb + tls_static_space;
4851 dtv = *(Elf_Addr **)tcb;
4853 for (i = 0; i < dtvsize; i++) {
4854 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4855 free((void*)dtv[i+2]);
4859 free_aligned(get_tls_block_ptr(tcb, tcbsize));
4864 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4867 * Allocate Static TLS using the Variant II method.
4870 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4873 size_t size, ralign;
4875 Elf_Addr *dtv, *olddtv;
4876 Elf_Addr segbase, oldsegbase, addr;
4880 if (tls_static_max_align > ralign)
4881 ralign = tls_static_max_align;
4882 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4884 assert(tcbsize >= 2*sizeof(Elf_Addr));
4885 tls = malloc_aligned(size, ralign);
4886 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4888 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4889 ((Elf_Addr*)segbase)[0] = segbase;
4890 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4892 dtv[0] = tls_dtv_generation;
4893 dtv[1] = tls_max_index;
4897 * Copy the static TLS block over whole.
4899 oldsegbase = (Elf_Addr) oldtls;
4900 memcpy((void *)(segbase - tls_static_space),
4901 (const void *)(oldsegbase - tls_static_space),
4905 * If any dynamic TLS blocks have been created tls_get_addr(),
4908 olddtv = ((Elf_Addr**)oldsegbase)[1];
4909 for (i = 0; i < olddtv[1]; i++) {
4910 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4911 dtv[i+2] = olddtv[i+2];
4917 * We assume that this block was the one we created with
4918 * allocate_initial_tls().
4920 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4922 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4923 if (obj->marker || obj->tlsoffset == 0)
4925 addr = segbase - obj->tlsoffset;
4926 memset((void*)(addr + obj->tlsinitsize),
4927 0, obj->tlssize - obj->tlsinitsize);
4929 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4930 dtv[obj->tlsindex + 1] = addr;
4934 return (void*) segbase;
4938 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign)
4941 size_t size, ralign;
4943 Elf_Addr tlsstart, tlsend;
4946 * Figure out the size of the initial TLS block so that we can
4947 * find stuff which ___tls_get_addr() allocated dynamically.
4950 if (tls_static_max_align > ralign)
4951 ralign = tls_static_max_align;
4952 size = round(tls_static_space, ralign);
4954 dtv = ((Elf_Addr**)tls)[1];
4956 tlsend = (Elf_Addr) tls;
4957 tlsstart = tlsend - size;
4958 for (i = 0; i < dtvsize; i++) {
4959 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4960 free_aligned((void *)dtv[i + 2]);
4964 free_aligned((void *)tlsstart);
4971 * Allocate TLS block for module with given index.
4974 allocate_module_tls(int index)
4979 TAILQ_FOREACH(obj, &obj_list, next) {
4982 if (obj->tlsindex == index)
4986 _rtld_error("Can't find module with TLS index %d", index);
4990 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4991 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4992 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4998 allocate_tls_offset(Obj_Entry *obj)
5005 if (obj->tlssize == 0) {
5006 obj->tls_done = true;
5010 if (tls_last_offset == 0)
5011 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
5013 off = calculate_tls_offset(tls_last_offset, tls_last_size,
5014 obj->tlssize, obj->tlsalign);
5017 * If we have already fixed the size of the static TLS block, we
5018 * must stay within that size. When allocating the static TLS, we
5019 * leave a small amount of space spare to be used for dynamically
5020 * loading modules which use static TLS.
5022 if (tls_static_space != 0) {
5023 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
5025 } else if (obj->tlsalign > tls_static_max_align) {
5026 tls_static_max_align = obj->tlsalign;
5029 tls_last_offset = obj->tlsoffset = off;
5030 tls_last_size = obj->tlssize;
5031 obj->tls_done = true;
5037 free_tls_offset(Obj_Entry *obj)
5041 * If we were the last thing to allocate out of the static TLS
5042 * block, we give our space back to the 'allocator'. This is a
5043 * simplistic workaround to allow libGL.so.1 to be loaded and
5044 * unloaded multiple times.
5046 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
5047 == calculate_tls_end(tls_last_offset, tls_last_size)) {
5048 tls_last_offset -= obj->tlssize;
5054 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
5057 RtldLockState lockstate;
5059 wlock_acquire(rtld_bind_lock, &lockstate);
5060 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
5062 lock_release(rtld_bind_lock, &lockstate);
5067 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
5069 RtldLockState lockstate;
5071 wlock_acquire(rtld_bind_lock, &lockstate);
5072 free_tls(tcb, tcbsize, tcbalign);
5073 lock_release(rtld_bind_lock, &lockstate);
5077 object_add_name(Obj_Entry *obj, const char *name)
5083 entry = malloc(sizeof(Name_Entry) + len);
5085 if (entry != NULL) {
5086 strcpy(entry->name, name);
5087 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5092 object_match_name(const Obj_Entry *obj, const char *name)
5096 STAILQ_FOREACH(entry, &obj->names, link) {
5097 if (strcmp(name, entry->name) == 0)
5104 locate_dependency(const Obj_Entry *obj, const char *name)
5106 const Objlist_Entry *entry;
5107 const Needed_Entry *needed;
5109 STAILQ_FOREACH(entry, &list_main, link) {
5110 if (object_match_name(entry->obj, name))
5114 for (needed = obj->needed; needed != NULL; needed = needed->next) {
5115 if (strcmp(obj->strtab + needed->name, name) == 0 ||
5116 (needed->obj != NULL && object_match_name(needed->obj, name))) {
5118 * If there is DT_NEEDED for the name we are looking for,
5119 * we are all set. Note that object might not be found if
5120 * dependency was not loaded yet, so the function can
5121 * return NULL here. This is expected and handled
5122 * properly by the caller.
5124 return (needed->obj);
5127 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
5133 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
5134 const Elf_Vernaux *vna)
5136 const Elf_Verdef *vd;
5137 const char *vername;
5139 vername = refobj->strtab + vna->vna_name;
5140 vd = depobj->verdef;
5142 _rtld_error("%s: version %s required by %s not defined",
5143 depobj->path, vername, refobj->path);
5147 if (vd->vd_version != VER_DEF_CURRENT) {
5148 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5149 depobj->path, vd->vd_version);
5152 if (vna->vna_hash == vd->vd_hash) {
5153 const Elf_Verdaux *aux = (const Elf_Verdaux *)
5154 ((const char *)vd + vd->vd_aux);
5155 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
5158 if (vd->vd_next == 0)
5160 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5162 if (vna->vna_flags & VER_FLG_WEAK)
5164 _rtld_error("%s: version %s required by %s not found",
5165 depobj->path, vername, refobj->path);
5170 rtld_verify_object_versions(Obj_Entry *obj)
5172 const Elf_Verneed *vn;
5173 const Elf_Verdef *vd;
5174 const Elf_Verdaux *vda;
5175 const Elf_Vernaux *vna;
5176 const Obj_Entry *depobj;
5177 int maxvernum, vernum;
5179 if (obj->ver_checked)
5181 obj->ver_checked = true;
5185 * Walk over defined and required version records and figure out
5186 * max index used by any of them. Do very basic sanity checking
5190 while (vn != NULL) {
5191 if (vn->vn_version != VER_NEED_CURRENT) {
5192 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
5193 obj->path, vn->vn_version);
5196 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5198 vernum = VER_NEED_IDX(vna->vna_other);
5199 if (vernum > maxvernum)
5201 if (vna->vna_next == 0)
5203 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5205 if (vn->vn_next == 0)
5207 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5211 while (vd != NULL) {
5212 if (vd->vd_version != VER_DEF_CURRENT) {
5213 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5214 obj->path, vd->vd_version);
5217 vernum = VER_DEF_IDX(vd->vd_ndx);
5218 if (vernum > maxvernum)
5220 if (vd->vd_next == 0)
5222 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5229 * Store version information in array indexable by version index.
5230 * Verify that object version requirements are satisfied along the
5233 obj->vernum = maxvernum + 1;
5234 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
5237 while (vd != NULL) {
5238 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
5239 vernum = VER_DEF_IDX(vd->vd_ndx);
5240 assert(vernum <= maxvernum);
5241 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux);
5242 obj->vertab[vernum].hash = vd->vd_hash;
5243 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
5244 obj->vertab[vernum].file = NULL;
5245 obj->vertab[vernum].flags = 0;
5247 if (vd->vd_next == 0)
5249 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5253 while (vn != NULL) {
5254 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
5257 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5259 if (check_object_provided_version(obj, depobj, vna))
5261 vernum = VER_NEED_IDX(vna->vna_other);
5262 assert(vernum <= maxvernum);
5263 obj->vertab[vernum].hash = vna->vna_hash;
5264 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
5265 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
5266 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
5267 VER_INFO_HIDDEN : 0;
5268 if (vna->vna_next == 0)
5270 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5272 if (vn->vn_next == 0)
5274 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5280 rtld_verify_versions(const Objlist *objlist)
5282 Objlist_Entry *entry;
5286 STAILQ_FOREACH(entry, objlist, link) {
5288 * Skip dummy objects or objects that have their version requirements
5291 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
5293 if (rtld_verify_object_versions(entry->obj) == -1) {
5295 if (ld_tracing == NULL)
5299 if (rc == 0 || ld_tracing != NULL)
5300 rc = rtld_verify_object_versions(&obj_rtld);
5305 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
5310 vernum = VER_NDX(obj->versyms[symnum]);
5311 if (vernum >= obj->vernum) {
5312 _rtld_error("%s: symbol %s has wrong verneed value %d",
5313 obj->path, obj->strtab + symnum, vernum);
5314 } else if (obj->vertab[vernum].hash != 0) {
5315 return &obj->vertab[vernum];
5322 _rtld_get_stack_prot(void)
5325 return (stack_prot);
5329 _rtld_is_dlopened(void *arg)
5332 RtldLockState lockstate;
5335 rlock_acquire(rtld_bind_lock, &lockstate);
5338 obj = obj_from_addr(arg);
5340 _rtld_error("No shared object contains address");
5341 lock_release(rtld_bind_lock, &lockstate);
5344 res = obj->dlopened ? 1 : 0;
5345 lock_release(rtld_bind_lock, &lockstate);
5350 obj_enforce_relro(Obj_Entry *obj)
5353 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size,
5355 _rtld_error("%s: Cannot enforce relro protection: %s",
5356 obj->path, rtld_strerror(errno));
5363 map_stacks_exec(RtldLockState *lockstate)
5365 void (*thr_map_stacks_exec)(void);
5367 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
5369 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
5370 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
5371 if (thr_map_stacks_exec != NULL) {
5372 stack_prot |= PROT_EXEC;
5373 thr_map_stacks_exec();
5378 symlook_init(SymLook *dst, const char *name)
5381 bzero(dst, sizeof(*dst));
5383 dst->hash = elf_hash(name);
5384 dst->hash_gnu = gnu_hash(name);
5388 symlook_init_from_req(SymLook *dst, const SymLook *src)
5391 dst->name = src->name;
5392 dst->hash = src->hash;
5393 dst->hash_gnu = src->hash_gnu;
5394 dst->ventry = src->ventry;
5395 dst->flags = src->flags;
5396 dst->defobj_out = NULL;
5397 dst->sym_out = NULL;
5398 dst->lockstate = src->lockstate;
5402 open_binary_fd(const char *argv0, bool search_in_path)
5404 char *pathenv, *pe, binpath[PATH_MAX];
5407 if (search_in_path && strchr(argv0, '/') == NULL) {
5408 pathenv = getenv("PATH");
5409 if (pathenv == NULL) {
5410 _rtld_error("-p and no PATH environment variable");
5413 pathenv = strdup(pathenv);
5414 if (pathenv == NULL) {
5415 _rtld_error("Cannot allocate memory");
5420 while ((pe = strsep(&pathenv, ":")) != NULL) {
5421 if (strlcpy(binpath, pe, sizeof(binpath)) >=
5424 if (binpath[0] != '\0' &&
5425 strlcat(binpath, "/", sizeof(binpath)) >=
5428 if (strlcat(binpath, argv0, sizeof(binpath)) >=
5431 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
5432 if (fd != -1 || errno != ENOENT)
5437 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
5441 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno));
5448 * Parse a set of command-line arguments.
5451 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp)
5454 int fd, i, j, arglen;
5457 dbg("Parsing command-line arguments");
5461 for (i = 1; i < argc; i++ ) {
5463 dbg("argv[%d]: '%s'", i, arg);
5466 * rtld arguments end with an explicit "--" or with the first
5467 * non-prefixed argument.
5469 if (strcmp(arg, "--") == 0) {
5477 * All other arguments are single-character options that can
5478 * be combined, so we need to search through `arg` for them.
5480 arglen = strlen(arg);
5481 for (j = 1; j < arglen; j++) {
5484 print_usage(argv[0]);
5486 } else if (opt == 'f') {
5488 * -f XX can be used to specify a descriptor for the
5489 * binary named at the command line (i.e., the later
5490 * argument will specify the process name but the
5491 * descriptor is what will actually be executed)
5493 if (j != arglen - 1) {
5494 /* -f must be the last option in, e.g., -abcf */
5495 _rtld_error("Invalid options: %s", arg);
5499 fd = parse_integer(argv[i]);
5501 _rtld_error("Invalid file descriptor: '%s'",
5507 } else if (opt == 'p') {
5510 _rtld_error("Invalid argument: '%s'", arg);
5511 print_usage(argv[0]);
5521 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
5524 parse_integer(const char *str)
5526 static const int RADIX = 10; /* XXXJA: possibly support hex? */
5533 for (c = *str; c != '\0'; c = *++str) {
5534 if (c < '0' || c > '9')
5541 /* Make sure we actually parsed something. */
5548 print_usage(const char *argv0)
5551 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n"
5554 " -h Display this help message\n"
5555 " -p Search in PATH for named binary\n"
5556 " -f <FD> Execute <FD> instead of searching for <binary>\n"
5557 " -- End of RTLD options\n"
5558 " <binary> Name of process to execute\n"
5559 " <args> Arguments to the executed process\n", argv0);
5563 * Overrides for libc_pic-provided functions.
5567 __getosreldate(void)
5577 oid[1] = KERN_OSRELDATE;
5579 len = sizeof(osrel);
5580 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5581 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5593 void (*__cleanup)(void);
5594 int __isthreaded = 0;
5595 int _thread_autoinit_dummy_decl = 1;
5598 * No unresolved symbols for rtld.
5601 __pthread_cxa_finalize(struct dl_phdr_info *a __unused)
5606 rtld_strerror(int errnum)
5609 if (errnum < 0 || errnum >= sys_nerr)
5610 return ("Unknown error");
5611 return (sys_errlist[errnum]);