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_malloc.h"
70 #include "rtld_utrace.h"
74 typedef void (*func_ptr_type)(void);
75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
78 /* Variables that cannot be static: */
79 extern struct r_debug r_debug; /* For GDB */
80 extern int _thread_autoinit_dummy_decl;
81 extern char* __progname;
82 extern void (*__cleanup)(void);
86 * Function declarations.
88 static const char *basename(const char *);
89 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
90 const Elf_Dyn **, const Elf_Dyn **);
91 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
93 static void digest_dynamic(Obj_Entry *, int);
94 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
95 static void distribute_static_tls(Objlist *, RtldLockState *);
96 static Obj_Entry *dlcheck(void *);
97 static int dlclose_locked(void *, RtldLockState *);
98 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
99 int lo_flags, int mode, RtldLockState *lockstate);
100 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
101 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
102 static bool donelist_check(DoneList *, const Obj_Entry *);
103 static void errmsg_restore(char *);
104 static char *errmsg_save(void);
105 static void *fill_search_info(const char *, size_t, void *);
106 static char *find_library(const char *, const Obj_Entry *, int *);
107 static const char *gethints(bool);
108 static void hold_object(Obj_Entry *);
109 static void unhold_object(Obj_Entry *);
110 static void init_dag(Obj_Entry *);
111 static void init_marker(Obj_Entry *);
112 static void init_pagesizes(Elf_Auxinfo **aux_info);
113 static void init_rtld(caddr_t, Elf_Auxinfo **);
114 static void initlist_add_neededs(Needed_Entry *, Objlist *);
115 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *);
116 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *);
117 static void linkmap_add(Obj_Entry *);
118 static void linkmap_delete(Obj_Entry *);
119 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
120 static void unload_filtees(Obj_Entry *, RtldLockState *);
121 static int load_needed_objects(Obj_Entry *, int);
122 static int load_preload_objects(void);
123 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
124 static void map_stacks_exec(RtldLockState *);
125 static int obj_disable_relro(Obj_Entry *);
126 static int obj_enforce_relro(Obj_Entry *);
127 static Obj_Entry *obj_from_addr(const void *);
128 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
129 static void objlist_call_init(Objlist *, RtldLockState *);
130 static void objlist_clear(Objlist *);
131 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
132 static void objlist_init(Objlist *);
133 static void objlist_push_head(Objlist *, Obj_Entry *);
134 static void objlist_push_tail(Objlist *, Obj_Entry *);
135 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
136 static void objlist_remove(Objlist *, Obj_Entry *);
137 static int open_binary_fd(const char *argv0, bool search_in_path);
138 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp);
139 static int parse_integer(const char *);
140 static void *path_enumerate(const char *, path_enum_proc, const char *, void *);
141 static void print_usage(const char *argv0);
142 static void release_object(Obj_Entry *);
143 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
144 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
145 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
146 int flags, RtldLockState *lockstate);
147 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
149 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *);
150 static int rtld_dirname(const char *, char *);
151 static int rtld_dirname_abs(const char *, char *);
152 static void *rtld_dlopen(const char *name, int fd, int mode);
153 static void rtld_exit(void);
154 static void rtld_nop_exit(void);
155 static char *search_library_path(const char *, const char *, const char *,
157 static char *search_library_pathfds(const char *, const char *, int *);
158 static const void **get_program_var_addr(const char *, RtldLockState *);
159 static void set_program_var(const char *, const void *);
160 static int symlook_default(SymLook *, const Obj_Entry *refobj);
161 static int symlook_global(SymLook *, DoneList *);
162 static void symlook_init_from_req(SymLook *, const SymLook *);
163 static int symlook_list(SymLook *, const Objlist *, DoneList *);
164 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
165 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
166 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
167 static void trace_loaded_objects(Obj_Entry *);
168 static void unlink_object(Obj_Entry *);
169 static void unload_object(Obj_Entry *, RtldLockState *lockstate);
170 static void unref_dag(Obj_Entry *);
171 static void ref_dag(Obj_Entry *);
172 static char *origin_subst_one(Obj_Entry *, char *, const char *,
174 static char *origin_subst(Obj_Entry *, const char *);
175 static bool obj_resolve_origin(Obj_Entry *obj);
176 static void preinit_main(void);
177 static int rtld_verify_versions(const Objlist *);
178 static int rtld_verify_object_versions(Obj_Entry *);
179 static void object_add_name(Obj_Entry *, const char *);
180 static int object_match_name(const Obj_Entry *, const char *);
181 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
182 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
183 struct dl_phdr_info *phdr_info);
184 static uint32_t gnu_hash(const char *);
185 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
186 const unsigned long);
188 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
189 void _r_debug_postinit(struct link_map *) __noinline __exported;
191 int __sys_openat(int, const char *, int, ...);
196 static char *error_message; /* Message for dlerror(), or NULL */
197 struct r_debug r_debug __exported; /* for GDB; */
198 static bool libmap_disable; /* Disable libmap */
199 static bool ld_loadfltr; /* Immediate filters processing */
200 static char *libmap_override; /* Maps to use in addition to libmap.conf */
201 static bool trust; /* False for setuid and setgid programs */
202 static bool dangerous_ld_env; /* True if environment variables have been
203 used to affect the libraries loaded */
204 bool ld_bind_not; /* Disable PLT update */
205 static char *ld_bind_now; /* Environment variable for immediate binding */
206 static char *ld_debug; /* Environment variable for debugging */
207 static char *ld_library_path; /* Environment variable for search path */
208 static char *ld_library_dirs; /* Environment variable for library descriptors */
209 static char *ld_preload; /* Environment variable for libraries to
211 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */
212 static const char *ld_tracing; /* Called from ldd to print libs */
213 static char *ld_utrace; /* Use utrace() to log events. */
214 static struct obj_entry_q obj_list; /* Queue of all loaded objects */
215 static Obj_Entry *obj_main; /* The main program shared object */
216 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
217 static unsigned int obj_count; /* Number of objects in obj_list */
218 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
220 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
221 STAILQ_HEAD_INITIALIZER(list_global);
222 static Objlist list_main = /* Objects loaded at program startup */
223 STAILQ_HEAD_INITIALIZER(list_main);
224 static Objlist list_fini = /* Objects needing fini() calls */
225 STAILQ_HEAD_INITIALIZER(list_fini);
227 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
229 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
231 extern Elf_Dyn _DYNAMIC;
232 #pragma weak _DYNAMIC
234 int dlclose(void *) __exported;
235 char *dlerror(void) __exported;
236 void *dlopen(const char *, int) __exported;
237 void *fdlopen(int, int) __exported;
238 void *dlsym(void *, const char *) __exported;
239 dlfunc_t dlfunc(void *, const char *) __exported;
240 void *dlvsym(void *, const char *, const char *) __exported;
241 int dladdr(const void *, Dl_info *) __exported;
242 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
243 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
244 int dlinfo(void *, int , void *) __exported;
245 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
246 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
247 int _rtld_get_stack_prot(void) __exported;
248 int _rtld_is_dlopened(void *) __exported;
249 void _rtld_error(const char *, ...) __exported;
251 /* Only here to fix -Wmissing-prototypes warnings */
252 int __getosreldate(void);
253 void __pthread_cxa_finalize(struct dl_phdr_info *a);
254 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp);
255 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff);
259 static int osreldate;
262 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
263 static int max_stack_flags;
266 * Global declarations normally provided by crt1. The dynamic linker is
267 * not built with crt1, so we have to provide them ourselves.
273 * Used to pass argc, argv to init functions.
279 * Globals to control TLS allocation.
281 size_t tls_last_offset; /* Static TLS offset of last module */
282 size_t tls_last_size; /* Static TLS size of last module */
283 size_t tls_static_space; /* Static TLS space allocated */
284 static size_t tls_static_max_align;
285 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */
286 int tls_max_index = 1; /* Largest module index allocated */
288 static bool ld_library_path_rpath = false;
291 * Globals for path names, and such
293 const char *ld_elf_hints_default = _PATH_ELF_HINTS;
294 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
295 const char *ld_path_rtld = _PATH_RTLD;
296 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
297 const char *ld_env_prefix = LD_;
299 static void (*rtld_exit_ptr)(void);
302 * Fill in a DoneList with an allocation large enough to hold all of
303 * the currently-loaded objects. Keep this as a macro since it calls
304 * alloca and we want that to occur within the scope of the caller.
306 #define donelist_init(dlp) \
307 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
308 assert((dlp)->objs != NULL), \
309 (dlp)->num_alloc = obj_count, \
312 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
313 if (ld_utrace != NULL) \
314 ld_utrace_log(e, h, mb, ms, r, n); \
318 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
319 int refcnt, const char *name)
321 struct utrace_rtld ut;
322 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG;
324 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig));
327 ut.mapbase = mapbase;
328 ut.mapsize = mapsize;
330 bzero(ut.name, sizeof(ut.name));
332 strlcpy(ut.name, name, sizeof(ut.name));
333 utrace(&ut, sizeof(ut));
336 #ifdef RTLD_VARIANT_ENV_NAMES
338 * construct the env variable based on the type of binary that's
341 static inline const char *
344 static char buffer[128];
346 strlcpy(buffer, ld_env_prefix, sizeof(buffer));
347 strlcat(buffer, var, sizeof(buffer));
355 * Main entry point for dynamic linking. The first argument is the
356 * stack pointer. The stack is expected to be laid out as described
357 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
358 * Specifically, the stack pointer points to a word containing
359 * ARGC. Following that in the stack is a null-terminated sequence
360 * of pointers to argument strings. Then comes a null-terminated
361 * sequence of pointers to environment strings. Finally, there is a
362 * sequence of "auxiliary vector" entries.
364 * The second argument points to a place to store the dynamic linker's
365 * exit procedure pointer and the third to a place to store the main
368 * The return value is the main program's entry point.
371 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
373 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT];
374 Objlist_Entry *entry;
375 Obj_Entry *last_interposer, *obj, *preload_tail;
376 const Elf_Phdr *phdr;
378 RtldLockState lockstate;
381 char **argv, **env, **envp, *kexecpath, *library_path_rpath;
384 char buf[MAXPATHLEN];
385 int argc, fd, i, phnum, rtld_argc;
386 bool dir_enable, explicit_fd, search_in_path;
389 * On entry, the dynamic linker itself has not been relocated yet.
390 * Be very careful not to reference any global data until after
391 * init_rtld has returned. It is OK to reference file-scope statics
392 * and string constants, and to call static and global functions.
395 /* Find the auxiliary vector on the stack. */
399 sp += argc + 1; /* Skip over arguments and NULL terminator */
401 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
403 aux = (Elf_Auxinfo *) sp;
405 /* Digest the auxiliary vector. */
406 for (i = 0; i < AT_COUNT; i++)
408 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
409 if (auxp->a_type < AT_COUNT)
410 aux_info[auxp->a_type] = auxp;
413 /* Initialize and relocate ourselves. */
414 assert(aux_info[AT_BASE] != NULL);
415 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
417 __progname = obj_rtld.path;
418 argv0 = argv[0] != NULL ? argv[0] : "(null)";
423 trust = !issetugid();
425 md_abi_variant_hook(aux_info);
428 if (aux_info[AT_EXECFD] != NULL) {
429 fd = aux_info[AT_EXECFD]->a_un.a_val;
431 assert(aux_info[AT_PHDR] != NULL);
432 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
433 if (phdr == obj_rtld.phdr) {
435 _rtld_error("Tainted process refusing to run binary %s",
439 dbg("opening main program in direct exec mode");
441 rtld_argc = parse_args(argv, argc, &search_in_path, &fd);
442 argv0 = argv[rtld_argc];
443 explicit_fd = (fd != -1);
445 fd = open_binary_fd(argv0, search_in_path);
446 if (fstat(fd, &st) == -1) {
447 _rtld_error("Failed to fstat FD %d (%s): %s", fd,
448 explicit_fd ? "user-provided descriptor" : argv0,
449 rtld_strerror(errno));
454 * Rough emulation of the permission checks done by
455 * execve(2), only Unix DACs are checked, ACLs are
456 * ignored. Preserve the semantic of disabling owner
457 * to execute if owner x bit is cleared, even if
458 * others x bit is enabled.
459 * mmap(2) does not allow to mmap with PROT_EXEC if
460 * binary' file comes from noexec mount. We cannot
461 * set a text reference on the binary.
464 if (st.st_uid == geteuid()) {
465 if ((st.st_mode & S_IXUSR) != 0)
467 } else if (st.st_gid == getegid()) {
468 if ((st.st_mode & S_IXGRP) != 0)
470 } else if ((st.st_mode & S_IXOTH) != 0) {
474 _rtld_error("No execute permission for binary %s",
480 * For direct exec mode, argv[0] is the interpreter
481 * name, we must remove it and shift arguments left
482 * before invoking binary main. Since stack layout
483 * places environment pointers and aux vectors right
484 * after the terminating NULL, we must shift
485 * environment and aux as well.
487 main_argc = argc - rtld_argc;
488 for (i = 0; i <= main_argc; i++)
489 argv[i] = argv[i + rtld_argc];
491 environ = env = envp = argv + main_argc + 1;
493 *envp = *(envp + rtld_argc);
495 } while (*envp != NULL);
496 aux = auxp = (Elf_Auxinfo *)envp;
497 auxpf = (Elf_Auxinfo *)(envp + rtld_argc);
498 for (;; auxp++, auxpf++) {
500 if (auxp->a_type == AT_NULL)
504 _rtld_error("No binary");
510 ld_bind_now = getenv(_LD("BIND_NOW"));
513 * If the process is tainted, then we un-set the dangerous environment
514 * variables. The process will be marked as tainted until setuid(2)
515 * is called. If any child process calls setuid(2) we do not want any
516 * future processes to honor the potentially un-safe variables.
519 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) ||
520 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) ||
521 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) ||
522 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) ||
523 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) {
524 _rtld_error("environment corrupt; aborting");
528 ld_debug = getenv(_LD("DEBUG"));
529 if (ld_bind_now == NULL)
530 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL;
531 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL;
532 libmap_override = getenv(_LD("LIBMAP"));
533 ld_library_path = getenv(_LD("LIBRARY_PATH"));
534 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS"));
535 ld_preload = getenv(_LD("PRELOAD"));
536 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH"));
537 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL;
538 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH"));
539 if (library_path_rpath != NULL) {
540 if (library_path_rpath[0] == 'y' ||
541 library_path_rpath[0] == 'Y' ||
542 library_path_rpath[0] == '1')
543 ld_library_path_rpath = true;
545 ld_library_path_rpath = false;
547 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
548 (ld_library_path != NULL) || (ld_preload != NULL) ||
549 (ld_elf_hints_path != NULL) || ld_loadfltr;
550 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS"));
551 ld_utrace = getenv(_LD("UTRACE"));
553 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
554 ld_elf_hints_path = ld_elf_hints_default;
556 if (ld_debug != NULL && *ld_debug != '\0')
558 dbg("%s is initialized, base address = %p", __progname,
559 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
560 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
561 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
563 dbg("initializing thread locks");
567 * Load the main program, or process its program header if it is
570 if (fd != -1) { /* Load the main program. */
571 dbg("loading main program");
572 obj_main = map_object(fd, argv0, NULL);
574 if (obj_main == NULL)
576 max_stack_flags = obj_main->stack_flags;
577 } else { /* Main program already loaded. */
578 dbg("processing main program's program header");
579 assert(aux_info[AT_PHDR] != NULL);
580 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
581 assert(aux_info[AT_PHNUM] != NULL);
582 phnum = aux_info[AT_PHNUM]->a_un.a_val;
583 assert(aux_info[AT_PHENT] != NULL);
584 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
585 assert(aux_info[AT_ENTRY] != NULL);
586 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
587 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL)
591 if (aux_info[AT_EXECPATH] != NULL && fd == -1) {
592 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
593 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
594 if (kexecpath[0] == '/')
595 obj_main->path = kexecpath;
596 else if (getcwd(buf, sizeof(buf)) == NULL ||
597 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
598 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
599 obj_main->path = xstrdup(argv0);
601 obj_main->path = xstrdup(buf);
603 dbg("No AT_EXECPATH or direct exec");
604 obj_main->path = xstrdup(argv0);
606 dbg("obj_main path %s", obj_main->path);
607 obj_main->mainprog = true;
609 if (aux_info[AT_STACKPROT] != NULL &&
610 aux_info[AT_STACKPROT]->a_un.a_val != 0)
611 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
615 * Get the actual dynamic linker pathname from the executable if
616 * possible. (It should always be possible.) That ensures that
617 * gdb will find the right dynamic linker even if a non-standard
620 if (obj_main->interp != NULL &&
621 strcmp(obj_main->interp, obj_rtld.path) != 0) {
623 obj_rtld.path = xstrdup(obj_main->interp);
624 __progname = obj_rtld.path;
628 digest_dynamic(obj_main, 0);
629 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
630 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
631 obj_main->dynsymcount);
633 linkmap_add(obj_main);
634 linkmap_add(&obj_rtld);
636 /* Link the main program into the list of objects. */
637 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
641 /* Initialize a fake symbol for resolving undefined weak references. */
642 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
643 sym_zero.st_shndx = SHN_UNDEF;
644 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
647 libmap_disable = (bool)lm_init(libmap_override);
649 dbg("loading LD_PRELOAD libraries");
650 if (load_preload_objects() == -1)
652 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
654 dbg("loading needed objects");
655 if (load_needed_objects(obj_main, 0) == -1)
658 /* Make a list of all objects loaded at startup. */
659 last_interposer = obj_main;
660 TAILQ_FOREACH(obj, &obj_list, next) {
663 if (obj->z_interpose && obj != obj_main) {
664 objlist_put_after(&list_main, last_interposer, obj);
665 last_interposer = obj;
667 objlist_push_tail(&list_main, obj);
672 dbg("checking for required versions");
673 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
676 if (ld_tracing) { /* We're done */
677 trace_loaded_objects(obj_main);
681 if (getenv(_LD("DUMP_REL_PRE")) != NULL) {
682 dump_relocations(obj_main);
687 * Processing tls relocations requires having the tls offsets
688 * initialized. Prepare offsets before starting initial
689 * relocation processing.
691 dbg("initializing initial thread local storage offsets");
692 STAILQ_FOREACH(entry, &list_main, link) {
694 * Allocate all the initial objects out of the static TLS
695 * block even if they didn't ask for it.
697 allocate_tls_offset(entry->obj);
700 if (relocate_objects(obj_main,
701 ld_bind_now != NULL && *ld_bind_now != '\0',
702 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
705 dbg("doing copy relocations");
706 if (do_copy_relocations(obj_main) == -1)
709 if (getenv(_LD("DUMP_REL_POST")) != NULL) {
710 dump_relocations(obj_main);
717 * Setup TLS for main thread. This must be done after the
718 * relocations are processed, since tls initialization section
719 * might be the subject for relocations.
721 dbg("initializing initial thread local storage");
722 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
724 dbg("initializing key program variables");
725 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
726 set_program_var("environ", env);
727 set_program_var("__elf_aux_vector", aux);
729 /* Make a list of init functions to call. */
730 objlist_init(&initlist);
731 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)),
732 preload_tail, &initlist);
734 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
736 map_stacks_exec(NULL);
738 if (!obj_main->crt_no_init) {
740 * Make sure we don't call the main program's init and fini
741 * functions for binaries linked with old crt1 which calls
744 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
745 obj_main->preinit_array = obj_main->init_array =
746 obj_main->fini_array = (Elf_Addr)NULL;
750 * Execute MD initializers required before we call the objects'
755 wlock_acquire(rtld_bind_lock, &lockstate);
757 dbg("resolving ifuncs");
758 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL &&
759 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1)
762 rtld_exit_ptr = rtld_exit;
763 if (obj_main->crt_no_init)
765 objlist_call_init(&initlist, &lockstate);
766 _r_debug_postinit(&obj_main->linkmap);
767 objlist_clear(&initlist);
768 dbg("loading filtees");
769 TAILQ_FOREACH(obj, &obj_list, next) {
772 if (ld_loadfltr || obj->z_loadfltr)
773 load_filtees(obj, 0, &lockstate);
776 dbg("enforcing main obj relro");
777 if (obj_enforce_relro(obj_main) == -1)
780 lock_release(rtld_bind_lock, &lockstate);
782 dbg("transferring control to program entry point = %p", obj_main->entry);
784 /* Return the exit procedure and the program entry point. */
785 *exit_proc = rtld_exit_ptr;
787 return (func_ptr_type) obj_main->entry;
791 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
796 ptr = (void *)make_function_pointer(def, obj);
797 target = call_ifunc_resolver(ptr);
798 return ((void *)target);
802 * NB: MIPS uses a private version of this function (_mips_rtld_bind).
803 * Changes to this function should be applied there as well.
806 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
810 const Obj_Entry *defobj;
813 RtldLockState lockstate;
815 rlock_acquire(rtld_bind_lock, &lockstate);
816 if (sigsetjmp(lockstate.env, 0) != 0)
817 lock_upgrade(rtld_bind_lock, &lockstate);
819 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff);
821 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff);
823 where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
824 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
828 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
829 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
831 target = (Elf_Addr)(defobj->relocbase + def->st_value);
833 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
834 defobj->strtab + def->st_name, basename(obj->path),
835 (void *)target, basename(defobj->path));
838 * Write the new contents for the jmpslot. Note that depending on
839 * architecture, the value which we need to return back to the
840 * lazy binding trampoline may or may not be the target
841 * address. The value returned from reloc_jmpslot() is the value
842 * that the trampoline needs.
844 target = reloc_jmpslot(where, target, defobj, obj, rel);
845 lock_release(rtld_bind_lock, &lockstate);
850 * Error reporting function. Use it like printf. If formats the message
851 * into a buffer, and sets things up so that the next call to dlerror()
852 * will return the message.
855 _rtld_error(const char *fmt, ...)
857 static char buf[512];
861 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
864 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message);
868 * Return a dynamically-allocated copy of the current error message, if any.
873 return error_message == NULL ? NULL : xstrdup(error_message);
877 * Restore the current error message from a copy which was previously saved
878 * by errmsg_save(). The copy is freed.
881 errmsg_restore(char *saved_msg)
883 if (saved_msg == NULL)
884 error_message = NULL;
886 _rtld_error("%s", saved_msg);
892 basename(const char *name)
894 const char *p = strrchr(name, '/');
895 return p != NULL ? p + 1 : name;
898 static struct utsname uts;
901 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
902 const char *subst, bool may_free)
904 char *p, *p1, *res, *resp;
905 int subst_len, kw_len, subst_count, old_len, new_len;
910 * First, count the number of the keyword occurrences, to
911 * preallocate the final string.
913 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
920 * If the keyword is not found, just return.
922 * Return non-substituted string if resolution failed. We
923 * cannot do anything more reasonable, the failure mode of the
924 * caller is unresolved library anyway.
926 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
927 return (may_free ? real : xstrdup(real));
929 subst = obj->origin_path;
932 * There is indeed something to substitute. Calculate the
933 * length of the resulting string, and allocate it.
935 subst_len = strlen(subst);
936 old_len = strlen(real);
937 new_len = old_len + (subst_len - kw_len) * subst_count;
938 res = xmalloc(new_len + 1);
941 * Now, execute the substitution loop.
943 for (p = real, resp = res, *resp = '\0';;) {
946 /* Copy the prefix before keyword. */
947 memcpy(resp, p, p1 - p);
949 /* Keyword replacement. */
950 memcpy(resp, subst, subst_len);
958 /* Copy to the end of string and finish. */
966 origin_subst(Obj_Entry *obj, const char *real)
968 char *res1, *res2, *res3, *res4;
970 if (obj == NULL || !trust)
971 return (xstrdup(real));
972 if (uts.sysname[0] == '\0') {
973 if (uname(&uts) != 0) {
974 _rtld_error("utsname failed: %d", errno);
978 /* __DECONST is safe here since without may_free real is unchanged */
979 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL,
981 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
982 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
983 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
990 const char *msg = dlerror();
994 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": ");
995 rtld_fdputstr(STDERR_FILENO, msg);
996 rtld_fdputchar(STDERR_FILENO, '\n');
1001 * Process a shared object's DYNAMIC section, and save the important
1002 * information in its Obj_Entry structure.
1005 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
1006 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
1008 const Elf_Dyn *dynp;
1009 Needed_Entry **needed_tail = &obj->needed;
1010 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
1011 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
1012 const Elf_Hashelt *hashtab;
1013 const Elf32_Word *hashval;
1014 Elf32_Word bkt, nmaskwords;
1016 int plttype = DT_REL;
1020 *dyn_runpath = NULL;
1022 obj->bind_now = false;
1023 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
1024 switch (dynp->d_tag) {
1027 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr);
1031 obj->relsize = dynp->d_un.d_val;
1035 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1039 obj->pltrel = (const Elf_Rel *)
1040 (obj->relocbase + dynp->d_un.d_ptr);
1044 obj->pltrelsize = dynp->d_un.d_val;
1048 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr);
1052 obj->relasize = dynp->d_un.d_val;
1056 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1060 plttype = dynp->d_un.d_val;
1061 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1065 obj->symtab = (const Elf_Sym *)
1066 (obj->relocbase + dynp->d_un.d_ptr);
1070 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1074 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr);
1078 obj->strsize = dynp->d_un.d_val;
1082 obj->verneed = (const Elf_Verneed *)(obj->relocbase +
1087 obj->verneednum = dynp->d_un.d_val;
1091 obj->verdef = (const Elf_Verdef *)(obj->relocbase +
1096 obj->verdefnum = dynp->d_un.d_val;
1100 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1106 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1108 obj->nbuckets = hashtab[0];
1109 obj->nchains = hashtab[1];
1110 obj->buckets = hashtab + 2;
1111 obj->chains = obj->buckets + obj->nbuckets;
1112 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1113 obj->buckets != NULL;
1119 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1121 obj->nbuckets_gnu = hashtab[0];
1122 obj->symndx_gnu = hashtab[1];
1123 nmaskwords = hashtab[2];
1124 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1125 obj->maskwords_bm_gnu = nmaskwords - 1;
1126 obj->shift2_gnu = hashtab[3];
1127 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4);
1128 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1129 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1131 /* Number of bitmask words is required to be power of 2 */
1132 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1133 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1139 Needed_Entry *nep = NEW(Needed_Entry);
1140 nep->name = dynp->d_un.d_val;
1145 needed_tail = &nep->next;
1151 Needed_Entry *nep = NEW(Needed_Entry);
1152 nep->name = dynp->d_un.d_val;
1156 *needed_filtees_tail = nep;
1157 needed_filtees_tail = &nep->next;
1163 Needed_Entry *nep = NEW(Needed_Entry);
1164 nep->name = dynp->d_un.d_val;
1168 *needed_aux_filtees_tail = nep;
1169 needed_aux_filtees_tail = &nep->next;
1174 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr);
1178 obj->textrel = true;
1182 obj->symbolic = true;
1187 * We have to wait until later to process this, because we
1188 * might not have gotten the address of the string table yet.
1198 *dyn_runpath = dynp;
1202 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1205 case DT_PREINIT_ARRAY:
1206 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1209 case DT_PREINIT_ARRAYSZ:
1210 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1214 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1217 case DT_INIT_ARRAYSZ:
1218 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1222 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1226 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1229 case DT_FINI_ARRAYSZ:
1230 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1234 * Don't process DT_DEBUG on MIPS as the dynamic section
1235 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1241 dbg("Filling in DT_DEBUG entry");
1242 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug;
1247 if (dynp->d_un.d_val & DF_ORIGIN)
1248 obj->z_origin = true;
1249 if (dynp->d_un.d_val & DF_SYMBOLIC)
1250 obj->symbolic = true;
1251 if (dynp->d_un.d_val & DF_TEXTREL)
1252 obj->textrel = true;
1253 if (dynp->d_un.d_val & DF_BIND_NOW)
1254 obj->bind_now = true;
1255 if (dynp->d_un.d_val & DF_STATIC_TLS)
1256 obj->static_tls = true;
1259 case DT_MIPS_LOCAL_GOTNO:
1260 obj->local_gotno = dynp->d_un.d_val;
1263 case DT_MIPS_SYMTABNO:
1264 obj->symtabno = dynp->d_un.d_val;
1267 case DT_MIPS_GOTSYM:
1268 obj->gotsym = dynp->d_un.d_val;
1271 case DT_MIPS_RLD_MAP:
1272 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1275 case DT_MIPS_RLD_MAP_REL:
1276 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map
1277 // section relative to the address of the tag itself.
1278 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) =
1279 (Elf_Addr) &r_debug;
1282 case DT_MIPS_PLTGOT:
1283 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase +
1289 #ifdef __powerpc64__
1290 case DT_PPC64_GLINK:
1291 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1296 if (dynp->d_un.d_val & DF_1_NOOPEN)
1297 obj->z_noopen = true;
1298 if (dynp->d_un.d_val & DF_1_ORIGIN)
1299 obj->z_origin = true;
1300 if (dynp->d_un.d_val & DF_1_GLOBAL)
1301 obj->z_global = true;
1302 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1303 obj->bind_now = true;
1304 if (dynp->d_un.d_val & DF_1_NODELETE)
1305 obj->z_nodelete = true;
1306 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1307 obj->z_loadfltr = true;
1308 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1309 obj->z_interpose = true;
1310 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1311 obj->z_nodeflib = true;
1316 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1323 obj->traced = false;
1325 if (plttype == DT_RELA) {
1326 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1328 obj->pltrelasize = obj->pltrelsize;
1329 obj->pltrelsize = 0;
1332 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1333 if (obj->valid_hash_sysv)
1334 obj->dynsymcount = obj->nchains;
1335 else if (obj->valid_hash_gnu) {
1336 obj->dynsymcount = 0;
1337 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1338 if (obj->buckets_gnu[bkt] == 0)
1340 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1343 while ((*hashval++ & 1u) == 0);
1345 obj->dynsymcount += obj->symndx_gnu;
1350 obj_resolve_origin(Obj_Entry *obj)
1353 if (obj->origin_path != NULL)
1355 obj->origin_path = xmalloc(PATH_MAX);
1356 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1360 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1361 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1364 if (obj->z_origin && !obj_resolve_origin(obj))
1367 if (dyn_runpath != NULL) {
1368 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val;
1369 obj->runpath = origin_subst(obj, obj->runpath);
1370 } else if (dyn_rpath != NULL) {
1371 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val;
1372 obj->rpath = origin_subst(obj, obj->rpath);
1374 if (dyn_soname != NULL)
1375 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1379 digest_dynamic(Obj_Entry *obj, int early)
1381 const Elf_Dyn *dyn_rpath;
1382 const Elf_Dyn *dyn_soname;
1383 const Elf_Dyn *dyn_runpath;
1385 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1386 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1390 * Process a shared object's program header. This is used only for the
1391 * main program, when the kernel has already loaded the main program
1392 * into memory before calling the dynamic linker. It creates and
1393 * returns an Obj_Entry structure.
1396 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1399 const Elf_Phdr *phlimit = phdr + phnum;
1401 Elf_Addr note_start, note_end;
1405 for (ph = phdr; ph < phlimit; ph++) {
1406 if (ph->p_type != PT_PHDR)
1410 obj->phsize = ph->p_memsz;
1411 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr;
1415 obj->stack_flags = PF_X | PF_R | PF_W;
1417 for (ph = phdr; ph < phlimit; ph++) {
1418 switch (ph->p_type) {
1421 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1425 if (nsegs == 0) { /* First load segment */
1426 obj->vaddrbase = trunc_page(ph->p_vaddr);
1427 obj->mapbase = obj->vaddrbase + obj->relocbase;
1428 } else { /* Last load segment */
1429 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1436 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1441 obj->tlssize = ph->p_memsz;
1442 obj->tlsalign = ph->p_align;
1443 obj->tlsinitsize = ph->p_filesz;
1444 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1448 obj->stack_flags = ph->p_flags;
1452 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1453 obj->relro_size = round_page(ph->p_memsz);
1457 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1458 note_end = note_start + ph->p_filesz;
1459 digest_notes(obj, note_start, note_end);
1464 _rtld_error("%s: too few PT_LOAD segments", path);
1473 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1475 const Elf_Note *note;
1476 const char *note_name;
1479 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1480 note = (const Elf_Note *)((const char *)(note + 1) +
1481 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1482 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1483 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1484 note->n_descsz != sizeof(int32_t))
1486 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1487 note->n_type != NT_FREEBSD_FEATURE_CTL &&
1488 note->n_type != NT_FREEBSD_NOINIT_TAG)
1490 note_name = (const char *)(note + 1);
1491 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1492 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1494 switch (note->n_type) {
1495 case NT_FREEBSD_ABI_TAG:
1496 /* FreeBSD osrel note */
1497 p = (uintptr_t)(note + 1);
1498 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1499 obj->osrel = *(const int32_t *)(p);
1500 dbg("note osrel %d", obj->osrel);
1502 case NT_FREEBSD_FEATURE_CTL:
1503 /* FreeBSD ABI feature control note */
1504 p = (uintptr_t)(note + 1);
1505 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1506 obj->fctl0 = *(const uint32_t *)(p);
1507 dbg("note fctl0 %#x", obj->fctl0);
1509 case NT_FREEBSD_NOINIT_TAG:
1510 /* FreeBSD 'crt does not call init' note */
1511 obj->crt_no_init = true;
1512 dbg("note crt_no_init");
1519 dlcheck(void *handle)
1523 TAILQ_FOREACH(obj, &obj_list, next) {
1524 if (obj == (Obj_Entry *) handle)
1528 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1529 _rtld_error("Invalid shared object handle %p", handle);
1536 * If the given object is already in the donelist, return true. Otherwise
1537 * add the object to the list and return false.
1540 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1544 for (i = 0; i < dlp->num_used; i++)
1545 if (dlp->objs[i] == obj)
1548 * Our donelist allocation should always be sufficient. But if
1549 * our threads locking isn't working properly, more shared objects
1550 * could have been loaded since we allocated the list. That should
1551 * never happen, but we'll handle it properly just in case it does.
1553 if (dlp->num_used < dlp->num_alloc)
1554 dlp->objs[dlp->num_used++] = obj;
1559 * Hash function for symbol table lookup. Don't even think about changing
1560 * this. It is specified by the System V ABI.
1563 elf_hash(const char *name)
1565 const unsigned char *p = (const unsigned char *) name;
1566 unsigned long h = 0;
1569 while (*p != '\0') {
1570 h = (h << 4) + *p++;
1571 if ((g = h & 0xf0000000) != 0)
1579 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1580 * unsigned in case it's implemented with a wider type.
1583 gnu_hash(const char *s)
1589 for (c = *s; c != '\0'; c = *++s)
1591 return (h & 0xffffffff);
1596 * Find the library with the given name, and return its full pathname.
1597 * The returned string is dynamically allocated. Generates an error
1598 * message and returns NULL if the library cannot be found.
1600 * If the second argument is non-NULL, then it refers to an already-
1601 * loaded shared object, whose library search path will be searched.
1603 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1604 * descriptor (which is close-on-exec) will be passed out via the third
1607 * The search order is:
1608 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1609 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1611 * DT_RUNPATH in the referencing file
1612 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1614 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1616 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1619 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1621 char *pathname, *refobj_path;
1623 bool nodeflib, objgiven;
1625 objgiven = refobj != NULL;
1627 if (libmap_disable || !objgiven ||
1628 (name = lm_find(refobj->path, xname)) == NULL)
1631 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1632 if (name[0] != '/' && !trust) {
1633 _rtld_error("Absolute pathname required "
1634 "for shared object \"%s\"", name);
1637 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1638 __DECONST(char *, name)));
1641 dbg(" Searching for \"%s\"", name);
1642 refobj_path = objgiven ? refobj->path : NULL;
1645 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1646 * back to pre-conforming behaviour if user requested so with
1647 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1650 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1651 pathname = search_library_path(name, ld_library_path,
1653 if (pathname != NULL)
1655 if (refobj != NULL) {
1656 pathname = search_library_path(name, refobj->rpath,
1658 if (pathname != NULL)
1661 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1662 if (pathname != NULL)
1664 pathname = search_library_path(name, gethints(false),
1666 if (pathname != NULL)
1668 pathname = search_library_path(name, ld_standard_library_path,
1670 if (pathname != NULL)
1673 nodeflib = objgiven ? refobj->z_nodeflib : false;
1675 pathname = search_library_path(name, refobj->rpath,
1677 if (pathname != NULL)
1680 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1681 pathname = search_library_path(name, obj_main->rpath,
1683 if (pathname != NULL)
1686 pathname = search_library_path(name, ld_library_path,
1688 if (pathname != NULL)
1691 pathname = search_library_path(name, refobj->runpath,
1693 if (pathname != NULL)
1696 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1697 if (pathname != NULL)
1699 pathname = search_library_path(name, gethints(nodeflib),
1701 if (pathname != NULL)
1703 if (objgiven && !nodeflib) {
1704 pathname = search_library_path(name,
1705 ld_standard_library_path, refobj_path, fdp);
1706 if (pathname != NULL)
1711 if (objgiven && refobj->path != NULL) {
1712 _rtld_error("Shared object \"%s\" not found, "
1713 "required by \"%s\"", name, basename(refobj->path));
1715 _rtld_error("Shared object \"%s\" not found", name);
1721 * Given a symbol number in a referencing object, find the corresponding
1722 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1723 * no definition was found. Returns a pointer to the Obj_Entry of the
1724 * defining object via the reference parameter DEFOBJ_OUT.
1727 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1728 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1729 RtldLockState *lockstate)
1733 const Obj_Entry *defobj;
1734 const Ver_Entry *ve;
1740 * If we have already found this symbol, get the information from
1743 if (symnum >= refobj->dynsymcount)
1744 return NULL; /* Bad object */
1745 if (cache != NULL && cache[symnum].sym != NULL) {
1746 *defobj_out = cache[symnum].obj;
1747 return cache[symnum].sym;
1750 ref = refobj->symtab + symnum;
1751 name = refobj->strtab + ref->st_name;
1757 * We don't have to do a full scale lookup if the symbol is local.
1758 * We know it will bind to the instance in this load module; to
1759 * which we already have a pointer (ie ref). By not doing a lookup,
1760 * we not only improve performance, but it also avoids unresolvable
1761 * symbols when local symbols are not in the hash table. This has
1762 * been seen with the ia64 toolchain.
1764 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1765 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1766 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1769 symlook_init(&req, name);
1771 ve = req.ventry = fetch_ventry(refobj, symnum);
1772 req.lockstate = lockstate;
1773 res = symlook_default(&req, refobj);
1776 defobj = req.defobj_out;
1784 * If we found no definition and the reference is weak, treat the
1785 * symbol as having the value zero.
1787 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1793 *defobj_out = defobj;
1794 /* Record the information in the cache to avoid subsequent lookups. */
1795 if (cache != NULL) {
1796 cache[symnum].sym = def;
1797 cache[symnum].obj = defobj;
1800 if (refobj != &obj_rtld)
1801 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name,
1802 ve != NULL ? "@" : "", ve != NULL ? ve->name : "");
1808 * Return the search path from the ldconfig hints file, reading it if
1809 * necessary. If nostdlib is true, then the default search paths are
1810 * not added to result.
1812 * Returns NULL if there are problems with the hints file,
1813 * or if the search path there is empty.
1816 gethints(bool nostdlib)
1818 static char *filtered_path;
1819 static const char *hints;
1820 static struct elfhints_hdr hdr;
1821 struct fill_search_info_args sargs, hargs;
1822 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1823 struct dl_serpath *SLPpath, *hintpath;
1825 struct stat hint_stat;
1826 unsigned int SLPndx, hintndx, fndx, fcount;
1832 /* First call, read the hints file */
1833 if (hints == NULL) {
1834 /* Keep from trying again in case the hints file is bad. */
1837 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1841 * Check of hdr.dirlistlen value against type limit
1842 * intends to pacify static analyzers. Further
1843 * paranoia leads to checks that dirlist is fully
1844 * contained in the file range.
1846 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1847 hdr.magic != ELFHINTS_MAGIC ||
1848 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 ||
1849 fstat(fd, &hint_stat) == -1) {
1856 if (dl + hdr.dirlist < dl)
1859 if (dl + hdr.dirlistlen < dl)
1861 dl += hdr.dirlistlen;
1862 if (dl > hint_stat.st_size)
1864 p = xmalloc(hdr.dirlistlen + 1);
1865 if (pread(fd, p, hdr.dirlistlen + 1,
1866 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 ||
1867 p[hdr.dirlistlen] != '\0') {
1876 * If caller agreed to receive list which includes the default
1877 * paths, we are done. Otherwise, if we still did not
1878 * calculated filtered result, do it now.
1881 return (hints[0] != '\0' ? hints : NULL);
1882 if (filtered_path != NULL)
1886 * Obtain the list of all configured search paths, and the
1887 * list of the default paths.
1889 * First estimate the size of the results.
1891 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1893 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1896 sargs.request = RTLD_DI_SERINFOSIZE;
1897 sargs.serinfo = &smeta;
1898 hargs.request = RTLD_DI_SERINFOSIZE;
1899 hargs.serinfo = &hmeta;
1901 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1903 path_enumerate(hints, fill_search_info, NULL, &hargs);
1905 SLPinfo = xmalloc(smeta.dls_size);
1906 hintinfo = xmalloc(hmeta.dls_size);
1909 * Next fetch both sets of paths.
1911 sargs.request = RTLD_DI_SERINFO;
1912 sargs.serinfo = SLPinfo;
1913 sargs.serpath = &SLPinfo->dls_serpath[0];
1914 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1916 hargs.request = RTLD_DI_SERINFO;
1917 hargs.serinfo = hintinfo;
1918 hargs.serpath = &hintinfo->dls_serpath[0];
1919 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1921 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1923 path_enumerate(hints, fill_search_info, NULL, &hargs);
1926 * Now calculate the difference between two sets, by excluding
1927 * standard paths from the full set.
1931 filtered_path = xmalloc(hdr.dirlistlen + 1);
1932 hintpath = &hintinfo->dls_serpath[0];
1933 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1935 SLPpath = &SLPinfo->dls_serpath[0];
1937 * Check each standard path against current.
1939 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1940 /* matched, skip the path */
1941 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1949 * Not matched against any standard path, add the path
1950 * to result. Separate consequtive paths with ':'.
1953 filtered_path[fndx] = ':';
1957 flen = strlen(hintpath->dls_name);
1958 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1961 filtered_path[fndx] = '\0';
1967 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1971 init_dag(Obj_Entry *root)
1973 const Needed_Entry *needed;
1974 const Objlist_Entry *elm;
1977 if (root->dag_inited)
1979 donelist_init(&donelist);
1981 /* Root object belongs to own DAG. */
1982 objlist_push_tail(&root->dldags, root);
1983 objlist_push_tail(&root->dagmembers, root);
1984 donelist_check(&donelist, root);
1987 * Add dependencies of root object to DAG in breadth order
1988 * by exploiting the fact that each new object get added
1989 * to the tail of the dagmembers list.
1991 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1992 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1993 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1995 objlist_push_tail(&needed->obj->dldags, root);
1996 objlist_push_tail(&root->dagmembers, needed->obj);
1999 root->dag_inited = true;
2003 init_marker(Obj_Entry *marker)
2006 bzero(marker, sizeof(*marker));
2007 marker->marker = true;
2011 globallist_curr(const Obj_Entry *obj)
2018 return (__DECONST(Obj_Entry *, obj));
2019 obj = TAILQ_PREV(obj, obj_entry_q, next);
2024 globallist_next(const Obj_Entry *obj)
2028 obj = TAILQ_NEXT(obj, next);
2032 return (__DECONST(Obj_Entry *, obj));
2036 /* Prevent the object from being unmapped while the bind lock is dropped. */
2038 hold_object(Obj_Entry *obj)
2045 unhold_object(Obj_Entry *obj)
2048 assert(obj->holdcount > 0);
2049 if (--obj->holdcount == 0 && obj->unholdfree)
2050 release_object(obj);
2054 process_z(Obj_Entry *root)
2056 const Objlist_Entry *elm;
2060 * Walk over object DAG and process every dependent object
2061 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2062 * to grow their own DAG.
2064 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2065 * symlook_global() to work.
2067 * For DF_1_NODELETE, the DAG should have its reference upped.
2069 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2073 if (obj->z_nodelete && !obj->ref_nodel) {
2074 dbg("obj %s -z nodelete", obj->path);
2077 obj->ref_nodel = true;
2079 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2080 dbg("obj %s -z global", obj->path);
2081 objlist_push_tail(&list_global, obj);
2087 * Initialize the dynamic linker. The argument is the address at which
2088 * the dynamic linker has been mapped into memory. The primary task of
2089 * this function is to relocate the dynamic linker.
2092 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2094 Obj_Entry objtmp; /* Temporary rtld object */
2095 const Elf_Ehdr *ehdr;
2096 const Elf_Dyn *dyn_rpath;
2097 const Elf_Dyn *dyn_soname;
2098 const Elf_Dyn *dyn_runpath;
2100 #ifdef RTLD_INIT_PAGESIZES_EARLY
2101 /* The page size is required by the dynamic memory allocator. */
2102 init_pagesizes(aux_info);
2106 * Conjure up an Obj_Entry structure for the dynamic linker.
2108 * The "path" member can't be initialized yet because string constants
2109 * cannot yet be accessed. Below we will set it correctly.
2111 memset(&objtmp, 0, sizeof(objtmp));
2114 objtmp.mapbase = mapbase;
2116 objtmp.relocbase = mapbase;
2119 objtmp.dynamic = rtld_dynamic(&objtmp);
2120 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2121 assert(objtmp.needed == NULL);
2122 #if !defined(__mips__)
2123 /* MIPS has a bogus DT_TEXTREL. */
2124 assert(!objtmp.textrel);
2127 * Temporarily put the dynamic linker entry into the object list, so
2128 * that symbols can be found.
2130 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2132 ehdr = (Elf_Ehdr *)mapbase;
2133 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2134 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]);
2136 /* Initialize the object list. */
2137 TAILQ_INIT(&obj_list);
2139 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2140 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2142 #ifndef RTLD_INIT_PAGESIZES_EARLY
2143 /* The page size is required by the dynamic memory allocator. */
2144 init_pagesizes(aux_info);
2147 if (aux_info[AT_OSRELDATE] != NULL)
2148 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2150 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2152 /* Replace the path with a dynamically allocated copy. */
2153 obj_rtld.path = xstrdup(ld_path_rtld);
2155 r_debug.r_brk = r_debug_state;
2156 r_debug.r_state = RT_CONSISTENT;
2160 * Retrieve the array of supported page sizes. The kernel provides the page
2161 * sizes in increasing order.
2164 init_pagesizes(Elf_Auxinfo **aux_info)
2166 static size_t psa[MAXPAGESIZES];
2170 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
2172 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2173 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2176 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2179 /* As a fallback, retrieve the base page size. */
2180 size = sizeof(psa[0]);
2181 if (aux_info[AT_PAGESZ] != NULL) {
2182 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2186 mib[1] = HW_PAGESIZE;
2190 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2191 _rtld_error("sysctl for hw.pagesize(s) failed");
2197 npagesizes = size / sizeof(pagesizes[0]);
2198 /* Discard any invalid entries at the end of the array. */
2199 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2204 * Add the init functions from a needed object list (and its recursive
2205 * needed objects) to "list". This is not used directly; it is a helper
2206 * function for initlist_add_objects(). The write lock must be held
2207 * when this function is called.
2210 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
2212 /* Recursively process the successor needed objects. */
2213 if (needed->next != NULL)
2214 initlist_add_neededs(needed->next, list);
2216 /* Process the current needed object. */
2217 if (needed->obj != NULL)
2218 initlist_add_objects(needed->obj, needed->obj, list);
2222 * Scan all of the DAGs rooted in the range of objects from "obj" to
2223 * "tail" and add their init functions to "list". This recurses over
2224 * the DAGs and ensure the proper init ordering such that each object's
2225 * needed libraries are initialized before the object itself. At the
2226 * same time, this function adds the objects to the global finalization
2227 * list "list_fini" in the opposite order. The write lock must be
2228 * held when this function is called.
2231 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2235 if (obj->init_scanned || obj->init_done)
2237 obj->init_scanned = true;
2239 /* Recursively process the successor objects. */
2240 nobj = globallist_next(obj);
2241 if (nobj != NULL && obj != tail)
2242 initlist_add_objects(nobj, tail, list);
2244 /* Recursively process the needed objects. */
2245 if (obj->needed != NULL)
2246 initlist_add_neededs(obj->needed, list);
2247 if (obj->needed_filtees != NULL)
2248 initlist_add_neededs(obj->needed_filtees, list);
2249 if (obj->needed_aux_filtees != NULL)
2250 initlist_add_neededs(obj->needed_aux_filtees, list);
2252 /* Add the object to the init list. */
2253 objlist_push_tail(list, obj);
2255 /* Add the object to the global fini list in the reverse order. */
2256 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2257 && !obj->on_fini_list) {
2258 objlist_push_head(&list_fini, obj);
2259 obj->on_fini_list = true;
2264 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2268 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2270 Needed_Entry *needed, *needed1;
2272 for (needed = n; needed != NULL; needed = needed->next) {
2273 if (needed->obj != NULL) {
2274 dlclose_locked(needed->obj, lockstate);
2278 for (needed = n; needed != NULL; needed = needed1) {
2279 needed1 = needed->next;
2285 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2288 free_needed_filtees(obj->needed_filtees, lockstate);
2289 obj->needed_filtees = NULL;
2290 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2291 obj->needed_aux_filtees = NULL;
2292 obj->filtees_loaded = false;
2296 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2297 RtldLockState *lockstate)
2300 for (; needed != NULL; needed = needed->next) {
2301 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2302 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2303 RTLD_LOCAL, lockstate);
2308 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2311 lock_restart_for_upgrade(lockstate);
2312 if (!obj->filtees_loaded) {
2313 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2314 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2315 obj->filtees_loaded = true;
2320 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2324 for (; needed != NULL; needed = needed->next) {
2325 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2326 flags & ~RTLD_LO_NOLOAD);
2327 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2334 * Given a shared object, traverse its list of needed objects, and load
2335 * each of them. Returns 0 on success. Generates an error message and
2336 * returns -1 on failure.
2339 load_needed_objects(Obj_Entry *first, int flags)
2343 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2346 if (process_needed(obj, obj->needed, flags) == -1)
2353 load_preload_objects(void)
2355 char *p = ld_preload;
2357 static const char delim[] = " \t:;";
2362 p += strspn(p, delim);
2363 while (*p != '\0') {
2364 size_t len = strcspn(p, delim);
2369 obj = load_object(p, -1, NULL, 0);
2371 return -1; /* XXX - cleanup */
2372 obj->z_interpose = true;
2375 p += strspn(p, delim);
2377 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2382 printable_path(const char *path)
2385 return (path == NULL ? "<unknown>" : path);
2389 * Load a shared object into memory, if it is not already loaded. The
2390 * object may be specified by name or by user-supplied file descriptor
2391 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2394 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2398 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2407 TAILQ_FOREACH(obj, &obj_list, next) {
2408 if (obj->marker || obj->doomed)
2410 if (object_match_name(obj, name))
2414 path = find_library(name, refobj, &fd);
2422 * search_library_pathfds() opens a fresh file descriptor for the
2423 * library, so there is no need to dup().
2425 } else if (fd_u == -1) {
2427 * If we didn't find a match by pathname, or the name is not
2428 * supplied, open the file and check again by device and inode.
2429 * This avoids false mismatches caused by multiple links or ".."
2432 * To avoid a race, we open the file and use fstat() rather than
2435 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2436 _rtld_error("Cannot open \"%s\"", path);
2441 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2443 _rtld_error("Cannot dup fd");
2448 if (fstat(fd, &sb) == -1) {
2449 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2454 TAILQ_FOREACH(obj, &obj_list, next) {
2455 if (obj->marker || obj->doomed)
2457 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2460 if (obj != NULL && name != NULL) {
2461 object_add_name(obj, name);
2466 if (flags & RTLD_LO_NOLOAD) {
2472 /* First use of this object, so we must map it in */
2473 obj = do_load_object(fd, name, path, &sb, flags);
2482 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2489 * but first, make sure that environment variables haven't been
2490 * used to circumvent the noexec flag on a filesystem.
2492 if (dangerous_ld_env) {
2493 if (fstatfs(fd, &fs) != 0) {
2494 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2497 if (fs.f_flags & MNT_NOEXEC) {
2498 _rtld_error("Cannot execute objects on %s", fs.f_mntonname);
2502 dbg("loading \"%s\"", printable_path(path));
2503 obj = map_object(fd, printable_path(path), sbp);
2508 * If DT_SONAME is present in the object, digest_dynamic2 already
2509 * added it to the object names.
2512 object_add_name(obj, name);
2514 digest_dynamic(obj, 0);
2515 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2516 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2517 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2519 dbg("refusing to load non-loadable \"%s\"", obj->path);
2520 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2521 munmap(obj->mapbase, obj->mapsize);
2526 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2527 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2530 linkmap_add(obj); /* for GDB & dlinfo() */
2531 max_stack_flags |= obj->stack_flags;
2533 dbg(" %p .. %p: %s", obj->mapbase,
2534 obj->mapbase + obj->mapsize - 1, obj->path);
2536 dbg(" WARNING: %s has impure text", obj->path);
2537 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2544 obj_from_addr(const void *addr)
2548 TAILQ_FOREACH(obj, &obj_list, next) {
2551 if (addr < (void *) obj->mapbase)
2553 if (addr < (void *)(obj->mapbase + obj->mapsize))
2562 Elf_Addr *preinit_addr;
2565 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2566 if (preinit_addr == NULL)
2569 for (index = 0; index < obj_main->preinit_array_num; index++) {
2570 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2571 dbg("calling preinit function for %s at %p", obj_main->path,
2572 (void *)preinit_addr[index]);
2573 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2574 0, 0, obj_main->path);
2575 call_init_pointer(obj_main, preinit_addr[index]);
2581 * Call the finalization functions for each of the objects in "list"
2582 * belonging to the DAG of "root" and referenced once. If NULL "root"
2583 * is specified, every finalization function will be called regardless
2584 * of the reference count and the list elements won't be freed. All of
2585 * the objects are expected to have non-NULL fini functions.
2588 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2592 Elf_Addr *fini_addr;
2595 assert(root == NULL || root->refcount == 1);
2598 root->doomed = true;
2601 * Preserve the current error message since a fini function might
2602 * call into the dynamic linker and overwrite it.
2604 saved_msg = errmsg_save();
2606 STAILQ_FOREACH(elm, list, link) {
2607 if (root != NULL && (elm->obj->refcount != 1 ||
2608 objlist_find(&root->dagmembers, elm->obj) == NULL))
2610 /* Remove object from fini list to prevent recursive invocation. */
2611 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2612 /* Ensure that new references cannot be acquired. */
2613 elm->obj->doomed = true;
2615 hold_object(elm->obj);
2616 lock_release(rtld_bind_lock, lockstate);
2618 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2619 * When this happens, DT_FINI_ARRAY is processed first.
2621 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2622 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2623 for (index = elm->obj->fini_array_num - 1; index >= 0;
2625 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2626 dbg("calling fini function for %s at %p",
2627 elm->obj->path, (void *)fini_addr[index]);
2628 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2629 (void *)fini_addr[index], 0, 0, elm->obj->path);
2630 call_initfini_pointer(elm->obj, fini_addr[index]);
2634 if (elm->obj->fini != (Elf_Addr)NULL) {
2635 dbg("calling fini function for %s at %p", elm->obj->path,
2636 (void *)elm->obj->fini);
2637 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2638 0, 0, elm->obj->path);
2639 call_initfini_pointer(elm->obj, elm->obj->fini);
2641 wlock_acquire(rtld_bind_lock, lockstate);
2642 unhold_object(elm->obj);
2643 /* No need to free anything if process is going down. */
2647 * We must restart the list traversal after every fini call
2648 * because a dlclose() call from the fini function or from
2649 * another thread might have modified the reference counts.
2653 } while (elm != NULL);
2654 errmsg_restore(saved_msg);
2658 * Call the initialization functions for each of the objects in
2659 * "list". All of the objects are expected to have non-NULL init
2663 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2668 Elf_Addr *init_addr;
2669 void (*reg)(void (*)(void));
2673 * Clean init_scanned flag so that objects can be rechecked and
2674 * possibly initialized earlier if any of vectors called below
2675 * cause the change by using dlopen.
2677 TAILQ_FOREACH(obj, &obj_list, next) {
2680 obj->init_scanned = false;
2684 * Preserve the current error message since an init function might
2685 * call into the dynamic linker and overwrite it.
2687 saved_msg = errmsg_save();
2688 STAILQ_FOREACH(elm, list, link) {
2689 if (elm->obj->init_done) /* Initialized early. */
2692 * Race: other thread might try to use this object before current
2693 * one completes the initialization. Not much can be done here
2694 * without better locking.
2696 elm->obj->init_done = true;
2697 hold_object(elm->obj);
2699 if (elm->obj == obj_main && obj_main->crt_no_init) {
2700 reg = (void (*)(void (*)(void)))get_program_var_addr(
2701 "__libc_atexit", lockstate);
2703 lock_release(rtld_bind_lock, lockstate);
2706 rtld_exit_ptr = rtld_nop_exit;
2710 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2711 * When this happens, DT_INIT is processed first.
2713 if (elm->obj->init != (Elf_Addr)NULL) {
2714 dbg("calling init function for %s at %p", elm->obj->path,
2715 (void *)elm->obj->init);
2716 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2717 0, 0, elm->obj->path);
2718 call_initfini_pointer(elm->obj, elm->obj->init);
2720 init_addr = (Elf_Addr *)elm->obj->init_array;
2721 if (init_addr != NULL) {
2722 for (index = 0; index < elm->obj->init_array_num; index++) {
2723 if (init_addr[index] != 0 && init_addr[index] != 1) {
2724 dbg("calling init function for %s at %p", elm->obj->path,
2725 (void *)init_addr[index]);
2726 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2727 (void *)init_addr[index], 0, 0, elm->obj->path);
2728 call_init_pointer(elm->obj, init_addr[index]);
2732 wlock_acquire(rtld_bind_lock, lockstate);
2733 unhold_object(elm->obj);
2735 errmsg_restore(saved_msg);
2739 objlist_clear(Objlist *list)
2743 while (!STAILQ_EMPTY(list)) {
2744 elm = STAILQ_FIRST(list);
2745 STAILQ_REMOVE_HEAD(list, link);
2750 static Objlist_Entry *
2751 objlist_find(Objlist *list, const Obj_Entry *obj)
2755 STAILQ_FOREACH(elm, list, link)
2756 if (elm->obj == obj)
2762 objlist_init(Objlist *list)
2768 objlist_push_head(Objlist *list, Obj_Entry *obj)
2772 elm = NEW(Objlist_Entry);
2774 STAILQ_INSERT_HEAD(list, elm, link);
2778 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2782 elm = NEW(Objlist_Entry);
2784 STAILQ_INSERT_TAIL(list, elm, link);
2788 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2790 Objlist_Entry *elm, *listelm;
2792 STAILQ_FOREACH(listelm, list, link) {
2793 if (listelm->obj == listobj)
2796 elm = NEW(Objlist_Entry);
2798 if (listelm != NULL)
2799 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2801 STAILQ_INSERT_TAIL(list, elm, link);
2805 objlist_remove(Objlist *list, Obj_Entry *obj)
2809 if ((elm = objlist_find(list, obj)) != NULL) {
2810 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2816 * Relocate dag rooted in the specified object.
2817 * Returns 0 on success, or -1 on failure.
2821 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2822 int flags, RtldLockState *lockstate)
2828 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2829 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2838 * Prepare for, or clean after, relocating an object marked with
2839 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
2840 * segments are remapped read-write. After relocations are done, the
2841 * segment's permissions are returned back to the modes specified in
2842 * the phdrs. If any relocation happened, or always for wired
2843 * program, COW is triggered.
2846 reloc_textrel_prot(Obj_Entry *obj, bool before)
2853 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
2855 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
2857 base = obj->relocbase + trunc_page(ph->p_vaddr);
2858 sz = round_page(ph->p_vaddr + ph->p_filesz) -
2859 trunc_page(ph->p_vaddr);
2860 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0);
2861 if (mprotect(base, sz, prot) == -1) {
2862 _rtld_error("%s: Cannot write-%sable text segment: %s",
2863 obj->path, before ? "en" : "dis",
2864 rtld_strerror(errno));
2872 * Relocate single object.
2873 * Returns 0 on success, or -1 on failure.
2876 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2877 int flags, RtldLockState *lockstate)
2882 obj->relocated = true;
2884 dbg("relocating \"%s\"", obj->path);
2886 if (obj->symtab == NULL || obj->strtab == NULL ||
2887 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2888 _rtld_error("%s: Shared object has no run-time symbol table",
2893 /* There are relocations to the write-protected text segment. */
2894 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
2897 /* Process the non-PLT non-IFUNC relocations. */
2898 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2901 /* Re-protected the text segment. */
2902 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
2905 /* Set the special PLT or GOT entries. */
2908 /* Process the PLT relocations. */
2909 if (reloc_plt(obj, flags, lockstate) == -1)
2911 /* Relocate the jump slots if we are doing immediate binding. */
2912 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags,
2916 if (!obj->mainprog && obj_enforce_relro(obj) == -1)
2920 * Set up the magic number and version in the Obj_Entry. These
2921 * were checked in the crt1.o from the original ElfKit, so we
2922 * set them for backward compatibility.
2924 obj->magic = RTLD_MAGIC;
2925 obj->version = RTLD_VERSION;
2931 * Relocate newly-loaded shared objects. The argument is a pointer to
2932 * the Obj_Entry for the first such object. All objects from the first
2933 * to the end of the list of objects are relocated. Returns 0 on success,
2937 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2938 int flags, RtldLockState *lockstate)
2943 for (error = 0, obj = first; obj != NULL;
2944 obj = TAILQ_NEXT(obj, next)) {
2947 error = relocate_object(obj, bind_now, rtldobj, flags,
2956 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2957 * referencing STT_GNU_IFUNC symbols is postponed till the other
2958 * relocations are done. The indirect functions specified as
2959 * ifunc are allowed to call other symbols, so we need to have
2960 * objects relocated before asking for resolution from indirects.
2962 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2963 * instead of the usual lazy handling of PLT slots. It is
2964 * consistent with how GNU does it.
2967 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2968 RtldLockState *lockstate)
2971 if (obj->ifuncs_resolved)
2973 obj->ifuncs_resolved = true;
2974 if (!obj->irelative && !((obj->bind_now || bind_now) && obj->gnu_ifunc))
2976 if (obj_disable_relro(obj) == -1 ||
2977 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) ||
2978 ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2979 reloc_gnu_ifunc(obj, flags, lockstate) == -1) ||
2980 obj_enforce_relro(obj) == -1)
2986 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2987 RtldLockState *lockstate)
2992 STAILQ_FOREACH(elm, list, link) {
2996 if (resolve_object_ifunc(obj, bind_now, flags,
3004 * Cleanup procedure. It will be called (by the atexit mechanism) just
3005 * before the process exits.
3010 RtldLockState lockstate;
3012 wlock_acquire(rtld_bind_lock, &lockstate);
3014 objlist_call_fini(&list_fini, NULL, &lockstate);
3015 /* No need to remove the items from the list, since we are exiting. */
3016 if (!libmap_disable)
3018 lock_release(rtld_bind_lock, &lockstate);
3027 * Iterate over a search path, translate each element, and invoke the
3028 * callback on the result.
3031 path_enumerate(const char *path, path_enum_proc callback,
3032 const char *refobj_path, void *arg)
3038 path += strspn(path, ":;");
3039 while (*path != '\0') {
3043 len = strcspn(path, ":;");
3044 trans = lm_findn(refobj_path, path, len);
3046 res = callback(trans, strlen(trans), arg);
3048 res = callback(path, len, arg);
3054 path += strspn(path, ":;");
3060 struct try_library_args {
3069 try_library_path(const char *dir, size_t dirlen, void *param)
3071 struct try_library_args *arg;
3075 if (*dir == '/' || trust) {
3078 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3081 pathname = arg->buffer;
3082 strncpy(pathname, dir, dirlen);
3083 pathname[dirlen] = '/';
3084 strcpy(pathname + dirlen + 1, arg->name);
3086 dbg(" Trying \"%s\"", pathname);
3087 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3089 dbg(" Opened \"%s\", fd %d", pathname, fd);
3090 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3091 strcpy(pathname, arg->buffer);
3095 dbg(" Failed to open \"%s\": %s",
3096 pathname, rtld_strerror(errno));
3103 search_library_path(const char *name, const char *path,
3104 const char *refobj_path, int *fdp)
3107 struct try_library_args arg;
3113 arg.namelen = strlen(name);
3114 arg.buffer = xmalloc(PATH_MAX);
3115 arg.buflen = PATH_MAX;
3118 p = path_enumerate(path, try_library_path, refobj_path, &arg);
3128 * Finds the library with the given name using the directory descriptors
3129 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3131 * Returns a freshly-opened close-on-exec file descriptor for the library,
3132 * or -1 if the library cannot be found.
3135 search_library_pathfds(const char *name, const char *path, int *fdp)
3137 char *envcopy, *fdstr, *found, *last_token;
3141 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3143 /* Don't load from user-specified libdirs into setuid binaries. */
3147 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3151 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3152 if (name[0] == '/') {
3153 dbg("Absolute path (%s) passed to %s", name, __func__);
3158 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3159 * copy of the path, as strtok_r rewrites separator tokens
3163 envcopy = xstrdup(path);
3164 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3165 fdstr = strtok_r(NULL, ":", &last_token)) {
3166 dirfd = parse_integer(fdstr);
3168 _rtld_error("failed to parse directory FD: '%s'",
3172 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3175 len = strlen(fdstr) + strlen(name) + 3;
3176 found = xmalloc(len);
3177 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
3178 _rtld_error("error generating '%d/%s'",
3182 dbg("open('%s') => %d", found, fd);
3193 dlclose(void *handle)
3195 RtldLockState lockstate;
3198 wlock_acquire(rtld_bind_lock, &lockstate);
3199 error = dlclose_locked(handle, &lockstate);
3200 lock_release(rtld_bind_lock, &lockstate);
3205 dlclose_locked(void *handle, RtldLockState *lockstate)
3209 root = dlcheck(handle);
3212 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3215 /* Unreference the object and its dependencies. */
3216 root->dl_refcount--;
3218 if (root->refcount == 1) {
3220 * The object will be no longer referenced, so we must unload it.
3221 * First, call the fini functions.
3223 objlist_call_fini(&list_fini, root, lockstate);
3227 /* Finish cleaning up the newly-unreferenced objects. */
3228 GDB_STATE(RT_DELETE,&root->linkmap);
3229 unload_object(root, lockstate);
3230 GDB_STATE(RT_CONSISTENT,NULL);
3234 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3241 char *msg = error_message;
3242 error_message = NULL;
3247 * This function is deprecated and has no effect.
3250 dllockinit(void *context,
3251 void *(*_lock_create)(void *context) __unused,
3252 void (*_rlock_acquire)(void *lock) __unused,
3253 void (*_wlock_acquire)(void *lock) __unused,
3254 void (*_lock_release)(void *lock) __unused,
3255 void (*_lock_destroy)(void *lock) __unused,
3256 void (*context_destroy)(void *context))
3258 static void *cur_context;
3259 static void (*cur_context_destroy)(void *);
3261 /* Just destroy the context from the previous call, if necessary. */
3262 if (cur_context_destroy != NULL)
3263 cur_context_destroy(cur_context);
3264 cur_context = context;
3265 cur_context_destroy = context_destroy;
3269 dlopen(const char *name, int mode)
3272 return (rtld_dlopen(name, -1, mode));
3276 fdlopen(int fd, int mode)
3279 return (rtld_dlopen(NULL, fd, mode));
3283 rtld_dlopen(const char *name, int fd, int mode)
3285 RtldLockState lockstate;
3288 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3289 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3290 if (ld_tracing != NULL) {
3291 rlock_acquire(rtld_bind_lock, &lockstate);
3292 if (sigsetjmp(lockstate.env, 0) != 0)
3293 lock_upgrade(rtld_bind_lock, &lockstate);
3294 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate));
3295 lock_release(rtld_bind_lock, &lockstate);
3297 lo_flags = RTLD_LO_DLOPEN;
3298 if (mode & RTLD_NODELETE)
3299 lo_flags |= RTLD_LO_NODELETE;
3300 if (mode & RTLD_NOLOAD)
3301 lo_flags |= RTLD_LO_NOLOAD;
3302 if (ld_tracing != NULL)
3303 lo_flags |= RTLD_LO_TRACE;
3305 return (dlopen_object(name, fd, obj_main, lo_flags,
3306 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3310 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3315 if (obj->refcount == 0)
3316 unload_object(obj, lockstate);
3320 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3321 int mode, RtldLockState *lockstate)
3323 Obj_Entry *old_obj_tail;
3326 RtldLockState mlockstate;
3329 objlist_init(&initlist);
3331 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3332 wlock_acquire(rtld_bind_lock, &mlockstate);
3333 lockstate = &mlockstate;
3335 GDB_STATE(RT_ADD,NULL);
3337 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
3339 if (name == NULL && fd == -1) {
3343 obj = load_object(name, fd, refobj, lo_flags);
3348 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3349 objlist_push_tail(&list_global, obj);
3350 if (globallist_next(old_obj_tail) != NULL) {
3351 /* We loaded something new. */
3352 assert(globallist_next(old_obj_tail) == obj);
3354 if ((lo_flags & RTLD_LO_EARLY) == 0 && obj->static_tls &&
3355 !allocate_tls_offset(obj)) {
3356 _rtld_error("%s: No space available "
3357 "for static Thread Local Storage", obj->path);
3361 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN |
3366 result = rtld_verify_versions(&obj->dagmembers);
3367 if (result != -1 && ld_tracing)
3369 if (result == -1 || relocate_object_dag(obj,
3370 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3371 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3373 dlopen_cleanup(obj, lockstate);
3375 } else if (lo_flags & RTLD_LO_EARLY) {
3377 * Do not call the init functions for early loaded
3378 * filtees. The image is still not initialized enough
3381 * Our object is found by the global object list and
3382 * will be ordered among all init calls done right
3383 * before transferring control to main.
3386 /* Make list of init functions to call. */
3387 initlist_add_objects(obj, obj, &initlist);
3390 * Process all no_delete or global objects here, given
3391 * them own DAGs to prevent their dependencies from being
3392 * unloaded. This has to be done after we have loaded all
3393 * of the dependencies, so that we do not miss any.
3399 * Bump the reference counts for objects on this DAG. If
3400 * this is the first dlopen() call for the object that was
3401 * already loaded as a dependency, initialize the dag
3407 if ((lo_flags & RTLD_LO_TRACE) != 0)
3410 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3411 obj->z_nodelete) && !obj->ref_nodel) {
3412 dbg("obj %s nodelete", obj->path);
3414 obj->z_nodelete = obj->ref_nodel = true;
3418 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3420 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3422 if ((lo_flags & RTLD_LO_EARLY) == 0) {
3423 map_stacks_exec(lockstate);
3425 distribute_static_tls(&initlist, lockstate);
3428 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3429 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3431 objlist_clear(&initlist);
3432 dlopen_cleanup(obj, lockstate);
3433 if (lockstate == &mlockstate)
3434 lock_release(rtld_bind_lock, lockstate);
3438 if (!(lo_flags & RTLD_LO_EARLY)) {
3439 /* Call the init functions. */
3440 objlist_call_init(&initlist, lockstate);
3442 objlist_clear(&initlist);
3443 if (lockstate == &mlockstate)
3444 lock_release(rtld_bind_lock, lockstate);
3447 trace_loaded_objects(obj);
3448 if (lockstate == &mlockstate)
3449 lock_release(rtld_bind_lock, lockstate);
3454 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3458 const Obj_Entry *obj, *defobj;
3461 RtldLockState lockstate;
3468 symlook_init(&req, name);
3470 req.flags = flags | SYMLOOK_IN_PLT;
3471 req.lockstate = &lockstate;
3473 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3474 rlock_acquire(rtld_bind_lock, &lockstate);
3475 if (sigsetjmp(lockstate.env, 0) != 0)
3476 lock_upgrade(rtld_bind_lock, &lockstate);
3477 if (handle == NULL || handle == RTLD_NEXT ||
3478 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3480 if ((obj = obj_from_addr(retaddr)) == NULL) {
3481 _rtld_error("Cannot determine caller's shared object");
3482 lock_release(rtld_bind_lock, &lockstate);
3483 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3486 if (handle == NULL) { /* Just the caller's shared object. */
3487 res = symlook_obj(&req, obj);
3490 defobj = req.defobj_out;
3492 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3493 handle == RTLD_SELF) { /* ... caller included */
3494 if (handle == RTLD_NEXT)
3495 obj = globallist_next(obj);
3496 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3499 res = symlook_obj(&req, obj);
3502 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3504 defobj = req.defobj_out;
3505 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3511 * Search the dynamic linker itself, and possibly resolve the
3512 * symbol from there. This is how the application links to
3513 * dynamic linker services such as dlopen.
3515 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3516 res = symlook_obj(&req, &obj_rtld);
3519 defobj = req.defobj_out;
3523 assert(handle == RTLD_DEFAULT);
3524 res = symlook_default(&req, obj);
3526 defobj = req.defobj_out;
3531 if ((obj = dlcheck(handle)) == NULL) {
3532 lock_release(rtld_bind_lock, &lockstate);
3533 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3537 donelist_init(&donelist);
3538 if (obj->mainprog) {
3539 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3540 res = symlook_global(&req, &donelist);
3543 defobj = req.defobj_out;
3546 * Search the dynamic linker itself, and possibly resolve the
3547 * symbol from there. This is how the application links to
3548 * dynamic linker services such as dlopen.
3550 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3551 res = symlook_obj(&req, &obj_rtld);
3554 defobj = req.defobj_out;
3559 /* Search the whole DAG rooted at the given object. */
3560 res = symlook_list(&req, &obj->dagmembers, &donelist);
3563 defobj = req.defobj_out;
3569 lock_release(rtld_bind_lock, &lockstate);
3572 * The value required by the caller is derived from the value
3573 * of the symbol. this is simply the relocated value of the
3576 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3577 sym = make_function_pointer(def, defobj);
3578 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3579 sym = rtld_resolve_ifunc(defobj, def);
3580 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3581 ti.ti_module = defobj->tlsindex;
3582 ti.ti_offset = def->st_value;
3583 sym = __tls_get_addr(&ti);
3585 sym = defobj->relocbase + def->st_value;
3586 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3590 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
3591 ve != NULL ? ve->name : "");
3592 lock_release(rtld_bind_lock, &lockstate);
3593 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3598 dlsym(void *handle, const char *name)
3600 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3605 dlfunc(void *handle, const char *name)
3612 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3618 dlvsym(void *handle, const char *name, const char *version)
3622 ventry.name = version;
3624 ventry.hash = elf_hash(version);
3626 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3631 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3633 const Obj_Entry *obj;
3634 RtldLockState lockstate;
3636 rlock_acquire(rtld_bind_lock, &lockstate);
3637 obj = obj_from_addr(addr);
3639 _rtld_error("No shared object contains address");
3640 lock_release(rtld_bind_lock, &lockstate);
3643 rtld_fill_dl_phdr_info(obj, phdr_info);
3644 lock_release(rtld_bind_lock, &lockstate);
3649 dladdr(const void *addr, Dl_info *info)
3651 const Obj_Entry *obj;
3654 unsigned long symoffset;
3655 RtldLockState lockstate;
3657 rlock_acquire(rtld_bind_lock, &lockstate);
3658 obj = obj_from_addr(addr);
3660 _rtld_error("No shared object contains address");
3661 lock_release(rtld_bind_lock, &lockstate);
3664 info->dli_fname = obj->path;
3665 info->dli_fbase = obj->mapbase;
3666 info->dli_saddr = (void *)0;
3667 info->dli_sname = NULL;
3670 * Walk the symbol list looking for the symbol whose address is
3671 * closest to the address sent in.
3673 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3674 def = obj->symtab + symoffset;
3677 * For skip the symbol if st_shndx is either SHN_UNDEF or
3680 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3684 * If the symbol is greater than the specified address, or if it
3685 * is further away from addr than the current nearest symbol,
3688 symbol_addr = obj->relocbase + def->st_value;
3689 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3692 /* Update our idea of the nearest symbol. */
3693 info->dli_sname = obj->strtab + def->st_name;
3694 info->dli_saddr = symbol_addr;
3697 if (info->dli_saddr == addr)
3700 lock_release(rtld_bind_lock, &lockstate);
3705 dlinfo(void *handle, int request, void *p)
3707 const Obj_Entry *obj;
3708 RtldLockState lockstate;
3711 rlock_acquire(rtld_bind_lock, &lockstate);
3713 if (handle == NULL || handle == RTLD_SELF) {
3716 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3717 if ((obj = obj_from_addr(retaddr)) == NULL)
3718 _rtld_error("Cannot determine caller's shared object");
3720 obj = dlcheck(handle);
3723 lock_release(rtld_bind_lock, &lockstate);
3729 case RTLD_DI_LINKMAP:
3730 *((struct link_map const **)p) = &obj->linkmap;
3732 case RTLD_DI_ORIGIN:
3733 error = rtld_dirname(obj->path, p);
3736 case RTLD_DI_SERINFOSIZE:
3737 case RTLD_DI_SERINFO:
3738 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3742 _rtld_error("Invalid request %d passed to dlinfo()", request);
3746 lock_release(rtld_bind_lock, &lockstate);
3752 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3755 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3756 phdr_info->dlpi_name = obj->path;
3757 phdr_info->dlpi_phdr = obj->phdr;
3758 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3759 phdr_info->dlpi_tls_modid = obj->tlsindex;
3760 phdr_info->dlpi_tls_data = obj->tlsinit;
3761 phdr_info->dlpi_adds = obj_loads;
3762 phdr_info->dlpi_subs = obj_loads - obj_count;
3766 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3768 struct dl_phdr_info phdr_info;
3769 Obj_Entry *obj, marker;
3770 RtldLockState bind_lockstate, phdr_lockstate;
3773 init_marker(&marker);
3776 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3777 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3778 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
3779 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
3780 rtld_fill_dl_phdr_info(obj, &phdr_info);
3782 lock_release(rtld_bind_lock, &bind_lockstate);
3784 error = callback(&phdr_info, sizeof phdr_info, param);
3786 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3788 obj = globallist_next(&marker);
3789 TAILQ_REMOVE(&obj_list, &marker, next);
3791 lock_release(rtld_bind_lock, &bind_lockstate);
3792 lock_release(rtld_phdr_lock, &phdr_lockstate);
3798 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3799 lock_release(rtld_bind_lock, &bind_lockstate);
3800 error = callback(&phdr_info, sizeof(phdr_info), param);
3802 lock_release(rtld_phdr_lock, &phdr_lockstate);
3807 fill_search_info(const char *dir, size_t dirlen, void *param)
3809 struct fill_search_info_args *arg;
3813 if (arg->request == RTLD_DI_SERINFOSIZE) {
3814 arg->serinfo->dls_cnt ++;
3815 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3817 struct dl_serpath *s_entry;
3819 s_entry = arg->serpath;
3820 s_entry->dls_name = arg->strspace;
3821 s_entry->dls_flags = arg->flags;
3823 strncpy(arg->strspace, dir, dirlen);
3824 arg->strspace[dirlen] = '\0';
3826 arg->strspace += dirlen + 1;
3834 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3836 struct dl_serinfo _info;
3837 struct fill_search_info_args args;
3839 args.request = RTLD_DI_SERINFOSIZE;
3840 args.serinfo = &_info;
3842 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3845 path_enumerate(obj->rpath, fill_search_info, NULL, &args);
3846 path_enumerate(ld_library_path, fill_search_info, NULL, &args);
3847 path_enumerate(obj->runpath, fill_search_info, NULL, &args);
3848 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args);
3849 if (!obj->z_nodeflib)
3850 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args);
3853 if (request == RTLD_DI_SERINFOSIZE) {
3854 info->dls_size = _info.dls_size;
3855 info->dls_cnt = _info.dls_cnt;
3859 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3860 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3864 args.request = RTLD_DI_SERINFO;
3865 args.serinfo = info;
3866 args.serpath = &info->dls_serpath[0];
3867 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3869 args.flags = LA_SER_RUNPATH;
3870 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL)
3873 args.flags = LA_SER_LIBPATH;
3874 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL)
3877 args.flags = LA_SER_RUNPATH;
3878 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL)
3881 args.flags = LA_SER_CONFIG;
3882 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args)
3886 args.flags = LA_SER_DEFAULT;
3887 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path,
3888 fill_search_info, NULL, &args) != NULL)
3894 rtld_dirname(const char *path, char *bname)
3898 /* Empty or NULL string gets treated as "." */
3899 if (path == NULL || *path == '\0') {
3905 /* Strip trailing slashes */
3906 endp = path + strlen(path) - 1;
3907 while (endp > path && *endp == '/')
3910 /* Find the start of the dir */
3911 while (endp > path && *endp != '/')
3914 /* Either the dir is "/" or there are no slashes */
3916 bname[0] = *endp == '/' ? '/' : '.';
3922 } while (endp > path && *endp == '/');
3925 if (endp - path + 2 > PATH_MAX)
3927 _rtld_error("Filename is too long: %s", path);
3931 strncpy(bname, path, endp - path + 1);
3932 bname[endp - path + 1] = '\0';
3937 rtld_dirname_abs(const char *path, char *base)
3941 if (realpath(path, base) == NULL)
3943 dbg("%s -> %s", path, base);
3944 last = strrchr(base, '/');
3953 linkmap_add(Obj_Entry *obj)
3955 struct link_map *l = &obj->linkmap;
3956 struct link_map *prev;
3958 obj->linkmap.l_name = obj->path;
3959 obj->linkmap.l_addr = obj->mapbase;
3960 obj->linkmap.l_ld = obj->dynamic;
3962 /* GDB needs load offset on MIPS to use the symbols */
3963 obj->linkmap.l_offs = obj->relocbase;
3966 if (r_debug.r_map == NULL) {
3972 * Scan to the end of the list, but not past the entry for the
3973 * dynamic linker, which we want to keep at the very end.
3975 for (prev = r_debug.r_map;
3976 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3977 prev = prev->l_next)
3980 /* Link in the new entry. */
3982 l->l_next = prev->l_next;
3983 if (l->l_next != NULL)
3984 l->l_next->l_prev = l;
3989 linkmap_delete(Obj_Entry *obj)
3991 struct link_map *l = &obj->linkmap;
3993 if (l->l_prev == NULL) {
3994 if ((r_debug.r_map = l->l_next) != NULL)
3995 l->l_next->l_prev = NULL;
3999 if ((l->l_prev->l_next = l->l_next) != NULL)
4000 l->l_next->l_prev = l->l_prev;
4004 * Function for the debugger to set a breakpoint on to gain control.
4006 * The two parameters allow the debugger to easily find and determine
4007 * what the runtime loader is doing and to whom it is doing it.
4009 * When the loadhook trap is hit (r_debug_state, set at program
4010 * initialization), the arguments can be found on the stack:
4012 * +8 struct link_map *m
4013 * +4 struct r_debug *rd
4017 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused)
4020 * The following is a hack to force the compiler to emit calls to
4021 * this function, even when optimizing. If the function is empty,
4022 * the compiler is not obliged to emit any code for calls to it,
4023 * even when marked __noinline. However, gdb depends on those
4026 __compiler_membar();
4030 * A function called after init routines have completed. This can be used to
4031 * break before a program's entry routine is called, and can be used when
4032 * main is not available in the symbol table.
4035 _r_debug_postinit(struct link_map *m __unused)
4038 /* See r_debug_state(). */
4039 __compiler_membar();
4043 release_object(Obj_Entry *obj)
4046 if (obj->holdcount > 0) {
4047 obj->unholdfree = true;
4050 munmap(obj->mapbase, obj->mapsize);
4051 linkmap_delete(obj);
4056 * Get address of the pointer variable in the main program.
4057 * Prefer non-weak symbol over the weak one.
4059 static const void **
4060 get_program_var_addr(const char *name, RtldLockState *lockstate)
4065 symlook_init(&req, name);
4066 req.lockstate = lockstate;
4067 donelist_init(&donelist);
4068 if (symlook_global(&req, &donelist) != 0)
4070 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4071 return ((const void **)make_function_pointer(req.sym_out,
4073 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4074 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
4076 return ((const void **)(req.defobj_out->relocbase +
4077 req.sym_out->st_value));
4081 * Set a pointer variable in the main program to the given value. This
4082 * is used to set key variables such as "environ" before any of the
4083 * init functions are called.
4086 set_program_var(const char *name, const void *value)
4090 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4091 dbg("\"%s\": *%p <-- %p", name, addr, value);
4097 * Search the global objects, including dependencies and main object,
4098 * for the given symbol.
4101 symlook_global(SymLook *req, DoneList *donelist)
4104 const Objlist_Entry *elm;
4107 symlook_init_from_req(&req1, req);
4109 /* Search all objects loaded at program start up. */
4110 if (req->defobj_out == NULL ||
4111 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4112 res = symlook_list(&req1, &list_main, donelist);
4113 if (res == 0 && (req->defobj_out == NULL ||
4114 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4115 req->sym_out = req1.sym_out;
4116 req->defobj_out = req1.defobj_out;
4117 assert(req->defobj_out != NULL);
4121 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4122 STAILQ_FOREACH(elm, &list_global, link) {
4123 if (req->defobj_out != NULL &&
4124 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4126 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4127 if (res == 0 && (req->defobj_out == NULL ||
4128 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4129 req->sym_out = req1.sym_out;
4130 req->defobj_out = req1.defobj_out;
4131 assert(req->defobj_out != NULL);
4135 return (req->sym_out != NULL ? 0 : ESRCH);
4139 * Given a symbol name in a referencing object, find the corresponding
4140 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4141 * no definition was found. Returns a pointer to the Obj_Entry of the
4142 * defining object via the reference parameter DEFOBJ_OUT.
4145 symlook_default(SymLook *req, const Obj_Entry *refobj)
4148 const Objlist_Entry *elm;
4152 donelist_init(&donelist);
4153 symlook_init_from_req(&req1, req);
4156 * Look first in the referencing object if linked symbolically,
4157 * and similarly handle protected symbols.
4159 res = symlook_obj(&req1, refobj);
4160 if (res == 0 && (refobj->symbolic ||
4161 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) {
4162 req->sym_out = req1.sym_out;
4163 req->defobj_out = req1.defobj_out;
4164 assert(req->defobj_out != NULL);
4166 if (refobj->symbolic || req->defobj_out != NULL)
4167 donelist_check(&donelist, refobj);
4169 symlook_global(req, &donelist);
4171 /* Search all dlopened DAGs containing the referencing object. */
4172 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4173 if (req->sym_out != NULL &&
4174 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4176 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4177 if (res == 0 && (req->sym_out == NULL ||
4178 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4179 req->sym_out = req1.sym_out;
4180 req->defobj_out = req1.defobj_out;
4181 assert(req->defobj_out != NULL);
4186 * Search the dynamic linker itself, and possibly resolve the
4187 * symbol from there. This is how the application links to
4188 * dynamic linker services such as dlopen.
4190 if (req->sym_out == NULL ||
4191 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4192 res = symlook_obj(&req1, &obj_rtld);
4194 req->sym_out = req1.sym_out;
4195 req->defobj_out = req1.defobj_out;
4196 assert(req->defobj_out != NULL);
4200 return (req->sym_out != NULL ? 0 : ESRCH);
4204 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4207 const Obj_Entry *defobj;
4208 const Objlist_Entry *elm;
4214 STAILQ_FOREACH(elm, objlist, link) {
4215 if (donelist_check(dlp, elm->obj))
4217 symlook_init_from_req(&req1, req);
4218 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4219 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4221 defobj = req1.defobj_out;
4222 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4229 req->defobj_out = defobj;
4236 * Search the chain of DAGS cointed to by the given Needed_Entry
4237 * for a symbol of the given name. Each DAG is scanned completely
4238 * before advancing to the next one. Returns a pointer to the symbol,
4239 * or NULL if no definition was found.
4242 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4245 const Needed_Entry *n;
4246 const Obj_Entry *defobj;
4252 symlook_init_from_req(&req1, req);
4253 for (n = needed; n != NULL; n = n->next) {
4254 if (n->obj == NULL ||
4255 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
4257 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4259 defobj = req1.defobj_out;
4260 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4266 req->defobj_out = defobj;
4273 * Search the symbol table of a single shared object for a symbol of
4274 * the given name and version, if requested. Returns a pointer to the
4275 * symbol, or NULL if no definition was found. If the object is
4276 * filter, return filtered symbol from filtee.
4278 * The symbol's hash value is passed in for efficiency reasons; that
4279 * eliminates many recomputations of the hash value.
4282 symlook_obj(SymLook *req, const Obj_Entry *obj)
4286 int flags, res, mres;
4289 * If there is at least one valid hash at this point, we prefer to
4290 * use the faster GNU version if available.
4292 if (obj->valid_hash_gnu)
4293 mres = symlook_obj1_gnu(req, obj);
4294 else if (obj->valid_hash_sysv)
4295 mres = symlook_obj1_sysv(req, obj);
4300 if (obj->needed_filtees != NULL) {
4301 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4302 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4303 donelist_init(&donelist);
4304 symlook_init_from_req(&req1, req);
4305 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
4307 req->sym_out = req1.sym_out;
4308 req->defobj_out = req1.defobj_out;
4312 if (obj->needed_aux_filtees != NULL) {
4313 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4314 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4315 donelist_init(&donelist);
4316 symlook_init_from_req(&req1, req);
4317 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
4319 req->sym_out = req1.sym_out;
4320 req->defobj_out = req1.defobj_out;
4328 /* Symbol match routine common to both hash functions */
4330 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4331 const unsigned long symnum)
4334 const Elf_Sym *symp;
4337 symp = obj->symtab + symnum;
4338 strp = obj->strtab + symp->st_name;
4340 switch (ELF_ST_TYPE(symp->st_info)) {
4346 if (symp->st_value == 0)
4350 if (symp->st_shndx != SHN_UNDEF)
4353 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4354 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4361 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4364 if (req->ventry == NULL) {
4365 if (obj->versyms != NULL) {
4366 verndx = VER_NDX(obj->versyms[symnum]);
4367 if (verndx > obj->vernum) {
4369 "%s: symbol %s references wrong version %d",
4370 obj->path, obj->strtab + symnum, verndx);
4374 * If we are not called from dlsym (i.e. this
4375 * is a normal relocation from unversioned
4376 * binary), accept the symbol immediately if
4377 * it happens to have first version after this
4378 * shared object became versioned. Otherwise,
4379 * if symbol is versioned and not hidden,
4380 * remember it. If it is the only symbol with
4381 * this name exported by the shared object, it
4382 * will be returned as a match by the calling
4383 * function. If symbol is global (verndx < 2)
4384 * accept it unconditionally.
4386 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4387 verndx == VER_NDX_GIVEN) {
4388 result->sym_out = symp;
4391 else if (verndx >= VER_NDX_GIVEN) {
4392 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4394 if (result->vsymp == NULL)
4395 result->vsymp = symp;
4401 result->sym_out = symp;
4404 if (obj->versyms == NULL) {
4405 if (object_match_name(obj, req->ventry->name)) {
4406 _rtld_error("%s: object %s should provide version %s "
4407 "for symbol %s", obj_rtld.path, obj->path,
4408 req->ventry->name, obj->strtab + symnum);
4412 verndx = VER_NDX(obj->versyms[symnum]);
4413 if (verndx > obj->vernum) {
4414 _rtld_error("%s: symbol %s references wrong version %d",
4415 obj->path, obj->strtab + symnum, verndx);
4418 if (obj->vertab[verndx].hash != req->ventry->hash ||
4419 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4421 * Version does not match. Look if this is a
4422 * global symbol and if it is not hidden. If
4423 * global symbol (verndx < 2) is available,
4424 * use it. Do not return symbol if we are
4425 * called by dlvsym, because dlvsym looks for
4426 * a specific version and default one is not
4427 * what dlvsym wants.
4429 if ((req->flags & SYMLOOK_DLSYM) ||
4430 (verndx >= VER_NDX_GIVEN) ||
4431 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4435 result->sym_out = symp;
4440 * Search for symbol using SysV hash function.
4441 * obj->buckets is known not to be NULL at this point; the test for this was
4442 * performed with the obj->valid_hash_sysv assignment.
4445 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4447 unsigned long symnum;
4448 Sym_Match_Result matchres;
4450 matchres.sym_out = NULL;
4451 matchres.vsymp = NULL;
4452 matchres.vcount = 0;
4454 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4455 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4456 if (symnum >= obj->nchains)
4457 return (ESRCH); /* Bad object */
4459 if (matched_symbol(req, obj, &matchres, symnum)) {
4460 req->sym_out = matchres.sym_out;
4461 req->defobj_out = obj;
4465 if (matchres.vcount == 1) {
4466 req->sym_out = matchres.vsymp;
4467 req->defobj_out = obj;
4473 /* Search for symbol using GNU hash function */
4475 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4477 Elf_Addr bloom_word;
4478 const Elf32_Word *hashval;
4480 Sym_Match_Result matchres;
4481 unsigned int h1, h2;
4482 unsigned long symnum;
4484 matchres.sym_out = NULL;
4485 matchres.vsymp = NULL;
4486 matchres.vcount = 0;
4488 /* Pick right bitmask word from Bloom filter array */
4489 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4490 obj->maskwords_bm_gnu];
4492 /* Calculate modulus word size of gnu hash and its derivative */
4493 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4494 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4496 /* Filter out the "definitely not in set" queries */
4497 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4500 /* Locate hash chain and corresponding value element*/
4501 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4504 hashval = &obj->chain_zero_gnu[bucket];
4506 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4507 symnum = hashval - obj->chain_zero_gnu;
4508 if (matched_symbol(req, obj, &matchres, symnum)) {
4509 req->sym_out = matchres.sym_out;
4510 req->defobj_out = obj;
4514 } while ((*hashval++ & 1) == 0);
4515 if (matchres.vcount == 1) {
4516 req->sym_out = matchres.vsymp;
4517 req->defobj_out = obj;
4524 trace_loaded_objects(Obj_Entry *obj)
4526 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4529 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL)
4532 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL)
4533 fmt1 = "\t%o => %p (%x)\n";
4535 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL)
4536 fmt2 = "\t%o (%x)\n";
4538 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL"));
4540 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4541 Needed_Entry *needed;
4542 const char *name, *path;
4547 if (list_containers && obj->needed != NULL)
4548 rtld_printf("%s:\n", obj->path);
4549 for (needed = obj->needed; needed; needed = needed->next) {
4550 if (needed->obj != NULL) {
4551 if (needed->obj->traced && !list_containers)
4553 needed->obj->traced = true;
4554 path = needed->obj->path;
4558 name = obj->strtab + needed->name;
4559 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4561 fmt = is_lib ? fmt1 : fmt2;
4562 while ((c = *fmt++) != '\0') {
4588 rtld_putstr(main_local);
4591 rtld_putstr(obj_main->path);
4598 rtld_printf("%d", sodp->sod_major);
4601 rtld_printf("%d", sodp->sod_minor);
4608 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4621 * Unload a dlopened object and its dependencies from memory and from
4622 * our data structures. It is assumed that the DAG rooted in the
4623 * object has already been unreferenced, and that the object has a
4624 * reference count of 0.
4627 unload_object(Obj_Entry *root, RtldLockState *lockstate)
4629 Obj_Entry marker, *obj, *next;
4631 assert(root->refcount == 0);
4634 * Pass over the DAG removing unreferenced objects from
4635 * appropriate lists.
4637 unlink_object(root);
4639 /* Unmap all objects that are no longer referenced. */
4640 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
4641 next = TAILQ_NEXT(obj, next);
4642 if (obj->marker || obj->refcount != 0)
4644 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
4645 obj->mapsize, 0, obj->path);
4646 dbg("unloading \"%s\"", obj->path);
4648 * Unlink the object now to prevent new references from
4649 * being acquired while the bind lock is dropped in
4650 * recursive dlclose() invocations.
4652 TAILQ_REMOVE(&obj_list, obj, next);
4655 if (obj->filtees_loaded) {
4657 init_marker(&marker);
4658 TAILQ_INSERT_BEFORE(next, &marker, next);
4659 unload_filtees(obj, lockstate);
4660 next = TAILQ_NEXT(&marker, next);
4661 TAILQ_REMOVE(&obj_list, &marker, next);
4663 unload_filtees(obj, lockstate);
4665 release_object(obj);
4670 unlink_object(Obj_Entry *root)
4674 if (root->refcount == 0) {
4675 /* Remove the object from the RTLD_GLOBAL list. */
4676 objlist_remove(&list_global, root);
4678 /* Remove the object from all objects' DAG lists. */
4679 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4680 objlist_remove(&elm->obj->dldags, root);
4681 if (elm->obj != root)
4682 unlink_object(elm->obj);
4688 ref_dag(Obj_Entry *root)
4692 assert(root->dag_inited);
4693 STAILQ_FOREACH(elm, &root->dagmembers, link)
4694 elm->obj->refcount++;
4698 unref_dag(Obj_Entry *root)
4702 assert(root->dag_inited);
4703 STAILQ_FOREACH(elm, &root->dagmembers, link)
4704 elm->obj->refcount--;
4708 * Common code for MD __tls_get_addr().
4710 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4712 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4714 Elf_Addr *newdtv, *dtv;
4715 RtldLockState lockstate;
4719 /* Check dtv generation in case new modules have arrived */
4720 if (dtv[0] != tls_dtv_generation) {
4721 wlock_acquire(rtld_bind_lock, &lockstate);
4722 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4724 if (to_copy > tls_max_index)
4725 to_copy = tls_max_index;
4726 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4727 newdtv[0] = tls_dtv_generation;
4728 newdtv[1] = tls_max_index;
4730 lock_release(rtld_bind_lock, &lockstate);
4731 dtv = *dtvp = newdtv;
4734 /* Dynamically allocate module TLS if necessary */
4735 if (dtv[index + 1] == 0) {
4736 /* Signal safe, wlock will block out signals. */
4737 wlock_acquire(rtld_bind_lock, &lockstate);
4738 if (!dtv[index + 1])
4739 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4740 lock_release(rtld_bind_lock, &lockstate);
4742 return ((void *)(dtv[index + 1] + offset));
4746 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4751 /* Check dtv generation in case new modules have arrived */
4752 if (__predict_true(dtv[0] == tls_dtv_generation &&
4753 dtv[index + 1] != 0))
4754 return ((void *)(dtv[index + 1] + offset));
4755 return (tls_get_addr_slow(dtvp, index, offset));
4758 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
4759 defined(__powerpc__) || defined(__riscv)
4762 * Return pointer to allocated TLS block
4765 get_tls_block_ptr(void *tcb, size_t tcbsize)
4767 size_t extra_size, post_size, pre_size, tls_block_size;
4768 size_t tls_init_align;
4770 tls_init_align = MAX(obj_main->tlsalign, 1);
4772 /* Compute fragments sizes. */
4773 extra_size = tcbsize - TLS_TCB_SIZE;
4774 post_size = calculate_tls_post_size(tls_init_align);
4775 tls_block_size = tcbsize + post_size;
4776 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4778 return ((char *)tcb - pre_size - extra_size);
4782 * Allocate Static TLS using the Variant I method.
4784 * For details on the layout, see lib/libc/gen/tls.c.
4786 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as
4787 * it is based on tls_last_offset, and TLS offsets here are really TCB
4788 * offsets, whereas libc's tls_static_space is just the executable's static
4792 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4796 Elf_Addr *dtv, **tcb;
4799 size_t extra_size, maxalign, post_size, pre_size, tls_block_size;
4800 size_t tls_init_align;
4802 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4805 assert(tcbsize >= TLS_TCB_SIZE);
4806 maxalign = MAX(tcbalign, tls_static_max_align);
4807 tls_init_align = MAX(obj_main->tlsalign, 1);
4809 /* Compute fragmets sizes. */
4810 extra_size = tcbsize - TLS_TCB_SIZE;
4811 post_size = calculate_tls_post_size(tls_init_align);
4812 tls_block_size = tcbsize + post_size;
4813 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4814 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size;
4816 /* Allocate whole TLS block */
4817 tls_block = malloc_aligned(tls_block_size, maxalign);
4818 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size);
4820 if (oldtcb != NULL) {
4821 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize),
4823 free_aligned(get_tls_block_ptr(oldtcb, tcbsize));
4825 /* Adjust the DTV. */
4827 for (i = 0; i < dtv[1]; i++) {
4828 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4829 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4830 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb;
4834 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4836 dtv[0] = tls_dtv_generation;
4837 dtv[1] = tls_max_index;
4839 for (obj = globallist_curr(objs); obj != NULL;
4840 obj = globallist_next(obj)) {
4841 if (obj->tlsoffset > 0) {
4842 addr = (Elf_Addr)tcb + obj->tlsoffset;
4843 if (obj->tlsinitsize > 0)
4844 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4845 if (obj->tlssize > obj->tlsinitsize)
4846 memset((void*)(addr + obj->tlsinitsize), 0,
4847 obj->tlssize - obj->tlsinitsize);
4848 dtv[obj->tlsindex + 1] = addr;
4857 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
4860 Elf_Addr tlsstart, tlsend;
4862 size_t dtvsize, i, tls_init_align;
4864 assert(tcbsize >= TLS_TCB_SIZE);
4865 tls_init_align = MAX(obj_main->tlsalign, 1);
4867 /* Compute fragments sizes. */
4868 post_size = calculate_tls_post_size(tls_init_align);
4870 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size;
4871 tlsend = (Elf_Addr)tcb + tls_static_space;
4873 dtv = *(Elf_Addr **)tcb;
4875 for (i = 0; i < dtvsize; i++) {
4876 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4877 free((void*)dtv[i+2]);
4881 free_aligned(get_tls_block_ptr(tcb, tcbsize));
4886 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4889 * Allocate Static TLS using the Variant II method.
4892 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4895 size_t size, ralign;
4897 Elf_Addr *dtv, *olddtv;
4898 Elf_Addr segbase, oldsegbase, addr;
4902 if (tls_static_max_align > ralign)
4903 ralign = tls_static_max_align;
4904 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4906 assert(tcbsize >= 2*sizeof(Elf_Addr));
4907 tls = malloc_aligned(size, ralign);
4908 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4910 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4911 ((Elf_Addr*)segbase)[0] = segbase;
4912 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4914 dtv[0] = tls_dtv_generation;
4915 dtv[1] = tls_max_index;
4919 * Copy the static TLS block over whole.
4921 oldsegbase = (Elf_Addr) oldtls;
4922 memcpy((void *)(segbase - tls_static_space),
4923 (const void *)(oldsegbase - tls_static_space),
4927 * If any dynamic TLS blocks have been created tls_get_addr(),
4930 olddtv = ((Elf_Addr**)oldsegbase)[1];
4931 for (i = 0; i < olddtv[1]; i++) {
4932 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4933 dtv[i+2] = olddtv[i+2];
4939 * We assume that this block was the one we created with
4940 * allocate_initial_tls().
4942 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4944 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4945 if (obj->marker || obj->tlsoffset == 0)
4947 addr = segbase - obj->tlsoffset;
4948 memset((void*)(addr + obj->tlsinitsize),
4949 0, obj->tlssize - obj->tlsinitsize);
4951 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4952 obj->static_tls_copied = true;
4954 dtv[obj->tlsindex + 1] = addr;
4958 return (void*) segbase;
4962 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign)
4965 size_t size, ralign;
4967 Elf_Addr tlsstart, tlsend;
4970 * Figure out the size of the initial TLS block so that we can
4971 * find stuff which ___tls_get_addr() allocated dynamically.
4974 if (tls_static_max_align > ralign)
4975 ralign = tls_static_max_align;
4976 size = round(tls_static_space, ralign);
4978 dtv = ((Elf_Addr**)tls)[1];
4980 tlsend = (Elf_Addr) tls;
4981 tlsstart = tlsend - size;
4982 for (i = 0; i < dtvsize; i++) {
4983 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4984 free_aligned((void *)dtv[i + 2]);
4988 free_aligned((void *)tlsstart);
4995 * Allocate TLS block for module with given index.
4998 allocate_module_tls(int index)
5003 TAILQ_FOREACH(obj, &obj_list, next) {
5006 if (obj->tlsindex == index)
5010 _rtld_error("Can't find module with TLS index %d", index);
5014 p = malloc_aligned(obj->tlssize, obj->tlsalign);
5015 memcpy(p, obj->tlsinit, obj->tlsinitsize);
5016 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
5022 allocate_tls_offset(Obj_Entry *obj)
5029 if (obj->tlssize == 0) {
5030 obj->tls_done = true;
5034 if (tls_last_offset == 0)
5035 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
5037 off = calculate_tls_offset(tls_last_offset, tls_last_size,
5038 obj->tlssize, obj->tlsalign);
5041 * If we have already fixed the size of the static TLS block, we
5042 * must stay within that size. When allocating the static TLS, we
5043 * leave a small amount of space spare to be used for dynamically
5044 * loading modules which use static TLS.
5046 if (tls_static_space != 0) {
5047 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
5049 } else if (obj->tlsalign > tls_static_max_align) {
5050 tls_static_max_align = obj->tlsalign;
5053 tls_last_offset = obj->tlsoffset = off;
5054 tls_last_size = obj->tlssize;
5055 obj->tls_done = true;
5061 free_tls_offset(Obj_Entry *obj)
5065 * If we were the last thing to allocate out of the static TLS
5066 * block, we give our space back to the 'allocator'. This is a
5067 * simplistic workaround to allow libGL.so.1 to be loaded and
5068 * unloaded multiple times.
5070 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
5071 == calculate_tls_end(tls_last_offset, tls_last_size)) {
5072 tls_last_offset -= obj->tlssize;
5078 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
5081 RtldLockState lockstate;
5083 wlock_acquire(rtld_bind_lock, &lockstate);
5084 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
5086 lock_release(rtld_bind_lock, &lockstate);
5091 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
5093 RtldLockState lockstate;
5095 wlock_acquire(rtld_bind_lock, &lockstate);
5096 free_tls(tcb, tcbsize, tcbalign);
5097 lock_release(rtld_bind_lock, &lockstate);
5101 object_add_name(Obj_Entry *obj, const char *name)
5107 entry = malloc(sizeof(Name_Entry) + len);
5109 if (entry != NULL) {
5110 strcpy(entry->name, name);
5111 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5116 object_match_name(const Obj_Entry *obj, const char *name)
5120 STAILQ_FOREACH(entry, &obj->names, link) {
5121 if (strcmp(name, entry->name) == 0)
5128 locate_dependency(const Obj_Entry *obj, const char *name)
5130 const Objlist_Entry *entry;
5131 const Needed_Entry *needed;
5133 STAILQ_FOREACH(entry, &list_main, link) {
5134 if (object_match_name(entry->obj, name))
5138 for (needed = obj->needed; needed != NULL; needed = needed->next) {
5139 if (strcmp(obj->strtab + needed->name, name) == 0 ||
5140 (needed->obj != NULL && object_match_name(needed->obj, name))) {
5142 * If there is DT_NEEDED for the name we are looking for,
5143 * we are all set. Note that object might not be found if
5144 * dependency was not loaded yet, so the function can
5145 * return NULL here. This is expected and handled
5146 * properly by the caller.
5148 return (needed->obj);
5151 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
5157 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
5158 const Elf_Vernaux *vna)
5160 const Elf_Verdef *vd;
5161 const char *vername;
5163 vername = refobj->strtab + vna->vna_name;
5164 vd = depobj->verdef;
5166 _rtld_error("%s: version %s required by %s not defined",
5167 depobj->path, vername, refobj->path);
5171 if (vd->vd_version != VER_DEF_CURRENT) {
5172 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5173 depobj->path, vd->vd_version);
5176 if (vna->vna_hash == vd->vd_hash) {
5177 const Elf_Verdaux *aux = (const Elf_Verdaux *)
5178 ((const char *)vd + vd->vd_aux);
5179 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
5182 if (vd->vd_next == 0)
5184 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5186 if (vna->vna_flags & VER_FLG_WEAK)
5188 _rtld_error("%s: version %s required by %s not found",
5189 depobj->path, vername, refobj->path);
5194 rtld_verify_object_versions(Obj_Entry *obj)
5196 const Elf_Verneed *vn;
5197 const Elf_Verdef *vd;
5198 const Elf_Verdaux *vda;
5199 const Elf_Vernaux *vna;
5200 const Obj_Entry *depobj;
5201 int maxvernum, vernum;
5203 if (obj->ver_checked)
5205 obj->ver_checked = true;
5209 * Walk over defined and required version records and figure out
5210 * max index used by any of them. Do very basic sanity checking
5214 while (vn != NULL) {
5215 if (vn->vn_version != VER_NEED_CURRENT) {
5216 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
5217 obj->path, vn->vn_version);
5220 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5222 vernum = VER_NEED_IDX(vna->vna_other);
5223 if (vernum > maxvernum)
5225 if (vna->vna_next == 0)
5227 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5229 if (vn->vn_next == 0)
5231 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5235 while (vd != NULL) {
5236 if (vd->vd_version != VER_DEF_CURRENT) {
5237 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5238 obj->path, vd->vd_version);
5241 vernum = VER_DEF_IDX(vd->vd_ndx);
5242 if (vernum > maxvernum)
5244 if (vd->vd_next == 0)
5246 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5253 * Store version information in array indexable by version index.
5254 * Verify that object version requirements are satisfied along the
5257 obj->vernum = maxvernum + 1;
5258 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
5261 while (vd != NULL) {
5262 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
5263 vernum = VER_DEF_IDX(vd->vd_ndx);
5264 assert(vernum <= maxvernum);
5265 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux);
5266 obj->vertab[vernum].hash = vd->vd_hash;
5267 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
5268 obj->vertab[vernum].file = NULL;
5269 obj->vertab[vernum].flags = 0;
5271 if (vd->vd_next == 0)
5273 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5277 while (vn != NULL) {
5278 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
5281 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5283 if (check_object_provided_version(obj, depobj, vna))
5285 vernum = VER_NEED_IDX(vna->vna_other);
5286 assert(vernum <= maxvernum);
5287 obj->vertab[vernum].hash = vna->vna_hash;
5288 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
5289 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
5290 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
5291 VER_INFO_HIDDEN : 0;
5292 if (vna->vna_next == 0)
5294 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5296 if (vn->vn_next == 0)
5298 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5304 rtld_verify_versions(const Objlist *objlist)
5306 Objlist_Entry *entry;
5310 STAILQ_FOREACH(entry, objlist, link) {
5312 * Skip dummy objects or objects that have their version requirements
5315 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
5317 if (rtld_verify_object_versions(entry->obj) == -1) {
5319 if (ld_tracing == NULL)
5323 if (rc == 0 || ld_tracing != NULL)
5324 rc = rtld_verify_object_versions(&obj_rtld);
5329 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
5334 vernum = VER_NDX(obj->versyms[symnum]);
5335 if (vernum >= obj->vernum) {
5336 _rtld_error("%s: symbol %s has wrong verneed value %d",
5337 obj->path, obj->strtab + symnum, vernum);
5338 } else if (obj->vertab[vernum].hash != 0) {
5339 return &obj->vertab[vernum];
5346 _rtld_get_stack_prot(void)
5349 return (stack_prot);
5353 _rtld_is_dlopened(void *arg)
5356 RtldLockState lockstate;
5359 rlock_acquire(rtld_bind_lock, &lockstate);
5362 obj = obj_from_addr(arg);
5364 _rtld_error("No shared object contains address");
5365 lock_release(rtld_bind_lock, &lockstate);
5368 res = obj->dlopened ? 1 : 0;
5369 lock_release(rtld_bind_lock, &lockstate);
5374 obj_remap_relro(Obj_Entry *obj, int prot)
5377 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size,
5379 _rtld_error("%s: Cannot set relro protection to %#x: %s",
5380 obj->path, prot, rtld_strerror(errno));
5387 obj_disable_relro(Obj_Entry *obj)
5390 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE));
5394 obj_enforce_relro(Obj_Entry *obj)
5397 return (obj_remap_relro(obj, PROT_READ));
5401 map_stacks_exec(RtldLockState *lockstate)
5403 void (*thr_map_stacks_exec)(void);
5405 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
5407 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
5408 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
5409 if (thr_map_stacks_exec != NULL) {
5410 stack_prot |= PROT_EXEC;
5411 thr_map_stacks_exec();
5416 distribute_static_tls(Objlist *list, RtldLockState *lockstate)
5420 void (*distrib)(size_t, void *, size_t, size_t);
5422 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t)
5423 get_program_var_addr("__pthread_distribute_static_tls", lockstate);
5424 if (distrib == NULL)
5426 STAILQ_FOREACH(elm, list, link) {
5428 if (obj->marker || !obj->tls_done || obj->static_tls_copied)
5430 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize,
5432 obj->static_tls_copied = true;
5437 symlook_init(SymLook *dst, const char *name)
5440 bzero(dst, sizeof(*dst));
5442 dst->hash = elf_hash(name);
5443 dst->hash_gnu = gnu_hash(name);
5447 symlook_init_from_req(SymLook *dst, const SymLook *src)
5450 dst->name = src->name;
5451 dst->hash = src->hash;
5452 dst->hash_gnu = src->hash_gnu;
5453 dst->ventry = src->ventry;
5454 dst->flags = src->flags;
5455 dst->defobj_out = NULL;
5456 dst->sym_out = NULL;
5457 dst->lockstate = src->lockstate;
5461 open_binary_fd(const char *argv0, bool search_in_path)
5463 char *pathenv, *pe, binpath[PATH_MAX];
5466 if (search_in_path && strchr(argv0, '/') == NULL) {
5467 pathenv = getenv("PATH");
5468 if (pathenv == NULL) {
5469 _rtld_error("-p and no PATH environment variable");
5472 pathenv = strdup(pathenv);
5473 if (pathenv == NULL) {
5474 _rtld_error("Cannot allocate memory");
5479 while ((pe = strsep(&pathenv, ":")) != NULL) {
5480 if (strlcpy(binpath, pe, sizeof(binpath)) >=
5483 if (binpath[0] != '\0' &&
5484 strlcat(binpath, "/", sizeof(binpath)) >=
5487 if (strlcat(binpath, argv0, sizeof(binpath)) >=
5490 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
5491 if (fd != -1 || errno != ENOENT)
5496 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
5500 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno));
5507 * Parse a set of command-line arguments.
5510 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp)
5513 int fd, i, j, arglen;
5516 dbg("Parsing command-line arguments");
5520 for (i = 1; i < argc; i++ ) {
5522 dbg("argv[%d]: '%s'", i, arg);
5525 * rtld arguments end with an explicit "--" or with the first
5526 * non-prefixed argument.
5528 if (strcmp(arg, "--") == 0) {
5536 * All other arguments are single-character options that can
5537 * be combined, so we need to search through `arg` for them.
5539 arglen = strlen(arg);
5540 for (j = 1; j < arglen; j++) {
5543 print_usage(argv[0]);
5545 } else if (opt == 'f') {
5547 * -f XX can be used to specify a descriptor for the
5548 * binary named at the command line (i.e., the later
5549 * argument will specify the process name but the
5550 * descriptor is what will actually be executed)
5552 if (j != arglen - 1) {
5553 /* -f must be the last option in, e.g., -abcf */
5554 _rtld_error("Invalid options: %s", arg);
5558 fd = parse_integer(argv[i]);
5560 _rtld_error("Invalid file descriptor: '%s'",
5566 } else if (opt == 'p') {
5569 _rtld_error("Invalid argument: '%s'", arg);
5570 print_usage(argv[0]);
5580 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
5583 parse_integer(const char *str)
5585 static const int RADIX = 10; /* XXXJA: possibly support hex? */
5592 for (c = *str; c != '\0'; c = *++str) {
5593 if (c < '0' || c > '9')
5600 /* Make sure we actually parsed something. */
5607 print_usage(const char *argv0)
5610 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n"
5613 " -h Display this help message\n"
5614 " -p Search in PATH for named binary\n"
5615 " -f <FD> Execute <FD> instead of searching for <binary>\n"
5616 " -- End of RTLD options\n"
5617 " <binary> Name of process to execute\n"
5618 " <args> Arguments to the executed process\n", argv0);
5622 * Overrides for libc_pic-provided functions.
5626 __getosreldate(void)
5636 oid[1] = KERN_OSRELDATE;
5638 len = sizeof(osrel);
5639 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5640 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5652 void (*__cleanup)(void);
5653 int __isthreaded = 0;
5654 int _thread_autoinit_dummy_decl = 1;
5657 * No unresolved symbols for rtld.
5660 __pthread_cxa_finalize(struct dl_phdr_info *a __unused)
5665 rtld_strerror(int errnum)
5668 if (errnum < 0 || errnum >= sys_nerr)
5669 return ("Unknown error");
5670 return (sys_errlist[errnum]);
5674 * No ifunc relocations.
5677 memset(void *dest, int c, size_t len)
5681 for (i = 0; i < len; i++)
5682 ((char *)dest)[i] = c;
5687 bzero(void *dest, size_t len)
5691 for (i = 0; i < len; i++)
5692 ((char *)dest)[i] = 0;
5697 malloc(size_t nbytes)
5700 return (__crt_malloc(nbytes));
5704 calloc(size_t num, size_t size)
5707 return (__crt_calloc(num, size));
5718 realloc(void *cp, size_t nbytes)
5721 return (__crt_realloc(cp, nbytes));