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"
72 #include "rtld_libc.h"
75 typedef void (*func_ptr_type)(void);
76 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
79 /* Variables that cannot be static: */
80 extern struct r_debug r_debug; /* For GDB */
81 extern int _thread_autoinit_dummy_decl;
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 bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
93 static bool 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 const char **binpath_res);
139 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp);
140 static int parse_integer(const char *);
141 static void *path_enumerate(const char *, path_enum_proc, const char *, void *);
142 static void print_usage(const char *argv0);
143 static void release_object(Obj_Entry *);
144 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
145 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
146 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
147 int flags, RtldLockState *lockstate);
148 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
150 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *);
151 static int rtld_dirname(const char *, char *);
152 static int rtld_dirname_abs(const char *, char *);
153 static void *rtld_dlopen(const char *name, int fd, int mode);
154 static void rtld_exit(void);
155 static void rtld_nop_exit(void);
156 static char *search_library_path(const char *, const char *, const char *,
158 static char *search_library_pathfds(const char *, const char *, int *);
159 static const void **get_program_var_addr(const char *, RtldLockState *);
160 static void set_program_var(const char *, const void *);
161 static int symlook_default(SymLook *, const Obj_Entry *refobj);
162 static int symlook_global(SymLook *, DoneList *);
163 static void symlook_init_from_req(SymLook *, const SymLook *);
164 static int symlook_list(SymLook *, const Objlist *, DoneList *);
165 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
166 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
167 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
168 static void trace_loaded_objects(Obj_Entry *);
169 static void unlink_object(Obj_Entry *);
170 static void unload_object(Obj_Entry *, RtldLockState *lockstate);
171 static void unref_dag(Obj_Entry *);
172 static void ref_dag(Obj_Entry *);
173 static char *origin_subst_one(Obj_Entry *, char *, const char *,
175 static char *origin_subst(Obj_Entry *, const char *);
176 static bool obj_resolve_origin(Obj_Entry *obj);
177 static void preinit_main(void);
178 static int rtld_verify_versions(const Objlist *);
179 static int rtld_verify_object_versions(Obj_Entry *);
180 static void object_add_name(Obj_Entry *, const char *);
181 static int object_match_name(const Obj_Entry *, const char *);
182 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
183 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
184 struct dl_phdr_info *phdr_info);
185 static uint32_t gnu_hash(const char *);
186 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
187 const unsigned long);
189 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
190 void _r_debug_postinit(struct link_map *) __noinline __exported;
192 int __sys_openat(int, const char *, int, ...);
197 static char *error_message; /* Message for dlerror(), or NULL */
198 struct r_debug r_debug __exported; /* for GDB; */
199 static bool libmap_disable; /* Disable libmap */
200 static bool ld_loadfltr; /* Immediate filters processing */
201 static char *libmap_override; /* Maps to use in addition to libmap.conf */
202 static bool trust; /* False for setuid and setgid programs */
203 static bool dangerous_ld_env; /* True if environment variables have been
204 used to affect the libraries loaded */
205 bool ld_bind_not; /* Disable PLT update */
206 static char *ld_bind_now; /* Environment variable for immediate binding */
207 static char *ld_debug; /* Environment variable for debugging */
208 static char *ld_library_path; /* Environment variable for search path */
209 static char *ld_library_dirs; /* Environment variable for library descriptors */
210 static char *ld_preload; /* Environment variable for libraries to
212 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */
213 static const char *ld_tracing; /* Called from ldd to print libs */
214 static char *ld_utrace; /* Use utrace() to log events. */
215 static struct obj_entry_q obj_list; /* Queue of all loaded objects */
216 static Obj_Entry *obj_main; /* The main program shared object */
217 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
218 static unsigned int obj_count; /* Number of objects in obj_list */
219 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
221 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
222 STAILQ_HEAD_INITIALIZER(list_global);
223 static Objlist list_main = /* Objects loaded at program startup */
224 STAILQ_HEAD_INITIALIZER(list_main);
225 static Objlist list_fini = /* Objects needing fini() calls */
226 STAILQ_HEAD_INITIALIZER(list_fini);
228 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
230 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
232 extern Elf_Dyn _DYNAMIC;
233 #pragma weak _DYNAMIC
235 int dlclose(void *) __exported;
236 char *dlerror(void) __exported;
237 void *dlopen(const char *, int) __exported;
238 void *fdlopen(int, int) __exported;
239 void *dlsym(void *, const char *) __exported;
240 dlfunc_t dlfunc(void *, const char *) __exported;
241 void *dlvsym(void *, const char *, const char *) __exported;
242 int dladdr(const void *, Dl_info *) __exported;
243 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
244 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
245 int dlinfo(void *, int , void *) __exported;
246 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
247 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
248 int _rtld_get_stack_prot(void) __exported;
249 int _rtld_is_dlopened(void *) __exported;
250 void _rtld_error(const char *, ...) __exported;
252 /* Only here to fix -Wmissing-prototypes warnings */
253 int __getosreldate(void);
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;
289 bool ld_fast_sigblock = false;
292 * Globals for path names, and such
294 const char *ld_elf_hints_default = _PATH_ELF_HINTS;
295 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
296 const char *ld_path_rtld = _PATH_RTLD;
297 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
298 const char *ld_env_prefix = LD_;
300 static void (*rtld_exit_ptr)(void);
303 * Fill in a DoneList with an allocation large enough to hold all of
304 * the currently-loaded objects. Keep this as a macro since it calls
305 * alloca and we want that to occur within the scope of the caller.
307 #define donelist_init(dlp) \
308 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
309 assert((dlp)->objs != NULL), \
310 (dlp)->num_alloc = obj_count, \
313 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
314 if (ld_utrace != NULL) \
315 ld_utrace_log(e, h, mb, ms, r, n); \
319 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
320 int refcnt, const char *name)
322 struct utrace_rtld ut;
323 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG;
325 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig));
328 ut.mapbase = mapbase;
329 ut.mapsize = mapsize;
331 bzero(ut.name, sizeof(ut.name));
333 strlcpy(ut.name, name, sizeof(ut.name));
334 utrace(&ut, sizeof(ut));
337 #ifdef RTLD_VARIANT_ENV_NAMES
339 * construct the env variable based on the type of binary that's
342 static inline const char *
345 static char buffer[128];
347 strlcpy(buffer, ld_env_prefix, sizeof(buffer));
348 strlcat(buffer, var, sizeof(buffer));
356 * Main entry point for dynamic linking. The first argument is the
357 * stack pointer. The stack is expected to be laid out as described
358 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
359 * Specifically, the stack pointer points to a word containing
360 * ARGC. Following that in the stack is a null-terminated sequence
361 * of pointers to argument strings. Then comes a null-terminated
362 * sequence of pointers to environment strings. Finally, there is a
363 * sequence of "auxiliary vector" entries.
365 * The second argument points to a place to store the dynamic linker's
366 * exit procedure pointer and the third to a place to store the main
369 * The return value is the main program's entry point.
372 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
374 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT];
375 Objlist_Entry *entry;
376 Obj_Entry *last_interposer, *obj, *preload_tail;
377 const Elf_Phdr *phdr;
379 RtldLockState lockstate;
382 char **argv, **env, **envp, *kexecpath, *library_path_rpath;
383 const char *argv0, *binpath;
385 char buf[MAXPATHLEN];
386 int argc, fd, i, phnum, rtld_argc;
388 int old_auxv_format = 1;
390 bool dir_enable, explicit_fd, search_in_path;
393 * On entry, the dynamic linker itself has not been relocated yet.
394 * Be very careful not to reference any global data until after
395 * init_rtld has returned. It is OK to reference file-scope statics
396 * and string constants, and to call static and global functions.
399 /* Find the auxiliary vector on the stack. */
403 sp += argc + 1; /* Skip over arguments and NULL terminator */
405 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
407 aux = (Elf_Auxinfo *) sp;
409 /* Digest the auxiliary vector. */
410 for (i = 0; i < AT_COUNT; i++)
412 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
413 if (auxp->a_type < AT_COUNT)
414 aux_info[auxp->a_type] = auxp;
416 if (auxp->a_type == 23) /* AT_STACKPROT */
422 if (old_auxv_format) {
423 /* Remap from old-style auxv numbers. */
424 aux_info[23] = aux_info[21]; /* AT_STACKPROT */
425 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */
426 aux_info[19] = aux_info[17]; /* AT_NCPUS */
427 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */
428 aux_info[15] = aux_info[13]; /* AT_EXECPATH */
429 aux_info[13] = NULL; /* AT_GID */
431 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */
432 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */
433 aux_info[16] = aux_info[14]; /* AT_CANARY */
434 aux_info[14] = NULL; /* AT_EGID */
438 /* Initialize and relocate ourselves. */
439 assert(aux_info[AT_BASE] != NULL);
440 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
442 __progname = obj_rtld.path;
443 argv0 = argv[0] != NULL ? argv[0] : "(null)";
448 if (aux_info[AT_BSDFLAGS] != NULL &&
449 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0)
450 ld_fast_sigblock = true;
452 trust = !issetugid();
454 md_abi_variant_hook(aux_info);
457 if (aux_info[AT_EXECFD] != NULL) {
458 fd = aux_info[AT_EXECFD]->a_un.a_val;
460 assert(aux_info[AT_PHDR] != NULL);
461 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
462 if (phdr == obj_rtld.phdr) {
464 _rtld_error("Tainted process refusing to run binary %s",
468 dbg("opening main program in direct exec mode");
470 rtld_argc = parse_args(argv, argc, &search_in_path, &fd);
471 argv0 = argv[rtld_argc];
472 explicit_fd = (fd != -1);
475 fd = open_binary_fd(argv0, search_in_path, &binpath);
476 if (fstat(fd, &st) == -1) {
477 _rtld_error("Failed to fstat FD %d (%s): %s", fd,
478 explicit_fd ? "user-provided descriptor" : argv0,
479 rtld_strerror(errno));
484 * Rough emulation of the permission checks done by
485 * execve(2), only Unix DACs are checked, ACLs are
486 * ignored. Preserve the semantic of disabling owner
487 * to execute if owner x bit is cleared, even if
488 * others x bit is enabled.
489 * mmap(2) does not allow to mmap with PROT_EXEC if
490 * binary' file comes from noexec mount. We cannot
491 * set a text reference on the binary.
494 if (st.st_uid == geteuid()) {
495 if ((st.st_mode & S_IXUSR) != 0)
497 } else if (st.st_gid == getegid()) {
498 if ((st.st_mode & S_IXGRP) != 0)
500 } else if ((st.st_mode & S_IXOTH) != 0) {
504 _rtld_error("No execute permission for binary %s",
510 * For direct exec mode, argv[0] is the interpreter
511 * name, we must remove it and shift arguments left
512 * before invoking binary main. Since stack layout
513 * places environment pointers and aux vectors right
514 * after the terminating NULL, we must shift
515 * environment and aux as well.
517 main_argc = argc - rtld_argc;
518 for (i = 0; i <= main_argc; i++)
519 argv[i] = argv[i + rtld_argc];
521 environ = env = envp = argv + main_argc + 1;
522 dbg("move env from %p to %p", envp + rtld_argc, envp);
524 *envp = *(envp + rtld_argc);
525 } while (*envp++ != NULL);
526 aux = auxp = (Elf_Auxinfo *)envp;
527 auxpf = (Elf_Auxinfo *)(envp + rtld_argc);
528 dbg("move aux from %p to %p", auxpf, aux);
529 /* XXXKIB insert place for AT_EXECPATH if not present */
530 for (;; auxp++, auxpf++) {
532 if (auxp->a_type == AT_NULL)
535 /* Since the auxiliary vector has moved, redigest it. */
536 for (i = 0; i < AT_COUNT; i++)
538 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
539 if (auxp->a_type < AT_COUNT)
540 aux_info[auxp->a_type] = auxp;
543 /* Point AT_EXECPATH auxv and aux_info to the binary path. */
544 if (binpath == NULL) {
545 aux_info[AT_EXECPATH] = NULL;
547 if (aux_info[AT_EXECPATH] == NULL) {
548 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo));
549 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH;
551 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *,
555 _rtld_error("No binary");
561 ld_bind_now = getenv(_LD("BIND_NOW"));
564 * If the process is tainted, then we un-set the dangerous environment
565 * variables. The process will be marked as tainted until setuid(2)
566 * is called. If any child process calls setuid(2) we do not want any
567 * future processes to honor the potentially un-safe variables.
570 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) ||
571 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) ||
572 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) ||
573 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) ||
574 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) {
575 _rtld_error("environment corrupt; aborting");
579 ld_debug = getenv(_LD("DEBUG"));
580 if (ld_bind_now == NULL)
581 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL;
582 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL;
583 libmap_override = getenv(_LD("LIBMAP"));
584 ld_library_path = getenv(_LD("LIBRARY_PATH"));
585 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS"));
586 ld_preload = getenv(_LD("PRELOAD"));
587 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH"));
588 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL;
589 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH"));
590 if (library_path_rpath != NULL) {
591 if (library_path_rpath[0] == 'y' ||
592 library_path_rpath[0] == 'Y' ||
593 library_path_rpath[0] == '1')
594 ld_library_path_rpath = true;
596 ld_library_path_rpath = false;
598 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
599 (ld_library_path != NULL) || (ld_preload != NULL) ||
600 (ld_elf_hints_path != NULL) || ld_loadfltr;
601 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS"));
602 ld_utrace = getenv(_LD("UTRACE"));
604 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
605 ld_elf_hints_path = ld_elf_hints_default;
607 if (ld_debug != NULL && *ld_debug != '\0')
609 dbg("%s is initialized, base address = %p", __progname,
610 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
611 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
612 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
614 dbg("initializing thread locks");
618 * Load the main program, or process its program header if it is
621 if (fd != -1) { /* Load the main program. */
622 dbg("loading main program");
623 obj_main = map_object(fd, argv0, NULL);
625 if (obj_main == NULL)
627 max_stack_flags = obj_main->stack_flags;
628 } else { /* Main program already loaded. */
629 dbg("processing main program's program header");
630 assert(aux_info[AT_PHDR] != NULL);
631 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
632 assert(aux_info[AT_PHNUM] != NULL);
633 phnum = aux_info[AT_PHNUM]->a_un.a_val;
634 assert(aux_info[AT_PHENT] != NULL);
635 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
636 assert(aux_info[AT_ENTRY] != NULL);
637 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
638 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL)
642 if (aux_info[AT_EXECPATH] != NULL && fd == -1) {
643 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
644 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
645 if (kexecpath[0] == '/')
646 obj_main->path = kexecpath;
647 else if (getcwd(buf, sizeof(buf)) == NULL ||
648 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
649 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
650 obj_main->path = xstrdup(argv0);
652 obj_main->path = xstrdup(buf);
654 dbg("No AT_EXECPATH or direct exec");
655 obj_main->path = xstrdup(argv0);
657 dbg("obj_main path %s", obj_main->path);
658 obj_main->mainprog = true;
660 if (aux_info[AT_STACKPROT] != NULL &&
661 aux_info[AT_STACKPROT]->a_un.a_val != 0)
662 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
666 * Get the actual dynamic linker pathname from the executable if
667 * possible. (It should always be possible.) That ensures that
668 * gdb will find the right dynamic linker even if a non-standard
671 if (obj_main->interp != NULL &&
672 strcmp(obj_main->interp, obj_rtld.path) != 0) {
674 obj_rtld.path = xstrdup(obj_main->interp);
675 __progname = obj_rtld.path;
679 if (!digest_dynamic(obj_main, 0))
681 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
682 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
683 obj_main->dynsymcount);
685 linkmap_add(obj_main);
686 linkmap_add(&obj_rtld);
688 /* Link the main program into the list of objects. */
689 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
693 /* Initialize a fake symbol for resolving undefined weak references. */
694 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
695 sym_zero.st_shndx = SHN_UNDEF;
696 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
699 libmap_disable = (bool)lm_init(libmap_override);
701 dbg("loading LD_PRELOAD libraries");
702 if (load_preload_objects() == -1)
704 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
706 dbg("loading needed objects");
707 if (load_needed_objects(obj_main, 0) == -1)
710 /* Make a list of all objects loaded at startup. */
711 last_interposer = obj_main;
712 TAILQ_FOREACH(obj, &obj_list, next) {
715 if (obj->z_interpose && obj != obj_main) {
716 objlist_put_after(&list_main, last_interposer, obj);
717 last_interposer = obj;
719 objlist_push_tail(&list_main, obj);
724 dbg("checking for required versions");
725 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
728 if (ld_tracing) { /* We're done */
729 trace_loaded_objects(obj_main);
733 if (getenv(_LD("DUMP_REL_PRE")) != NULL) {
734 dump_relocations(obj_main);
739 * Processing tls relocations requires having the tls offsets
740 * initialized. Prepare offsets before starting initial
741 * relocation processing.
743 dbg("initializing initial thread local storage offsets");
744 STAILQ_FOREACH(entry, &list_main, link) {
746 * Allocate all the initial objects out of the static TLS
747 * block even if they didn't ask for it.
749 allocate_tls_offset(entry->obj);
752 if (relocate_objects(obj_main,
753 ld_bind_now != NULL && *ld_bind_now != '\0',
754 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
757 dbg("doing copy relocations");
758 if (do_copy_relocations(obj_main) == -1)
761 if (getenv(_LD("DUMP_REL_POST")) != NULL) {
762 dump_relocations(obj_main);
769 * Setup TLS for main thread. This must be done after the
770 * relocations are processed, since tls initialization section
771 * might be the subject for relocations.
773 dbg("initializing initial thread local storage");
774 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
776 dbg("initializing key program variables");
777 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
778 set_program_var("environ", env);
779 set_program_var("__elf_aux_vector", aux);
781 /* Make a list of init functions to call. */
782 objlist_init(&initlist);
783 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)),
784 preload_tail, &initlist);
786 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
788 map_stacks_exec(NULL);
790 if (!obj_main->crt_no_init) {
792 * Make sure we don't call the main program's init and fini
793 * functions for binaries linked with old crt1 which calls
796 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
797 obj_main->preinit_array = obj_main->init_array =
798 obj_main->fini_array = (Elf_Addr)NULL;
802 * Execute MD initializers required before we call the objects'
807 wlock_acquire(rtld_bind_lock, &lockstate);
809 dbg("resolving ifuncs");
810 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL &&
811 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1)
814 rtld_exit_ptr = rtld_exit;
815 if (obj_main->crt_no_init)
817 objlist_call_init(&initlist, &lockstate);
818 _r_debug_postinit(&obj_main->linkmap);
819 objlist_clear(&initlist);
820 dbg("loading filtees");
821 TAILQ_FOREACH(obj, &obj_list, next) {
824 if (ld_loadfltr || obj->z_loadfltr)
825 load_filtees(obj, 0, &lockstate);
828 dbg("enforcing main obj relro");
829 if (obj_enforce_relro(obj_main) == -1)
832 lock_release(rtld_bind_lock, &lockstate);
834 dbg("transferring control to program entry point = %p", obj_main->entry);
836 /* Return the exit procedure and the program entry point. */
837 *exit_proc = rtld_exit_ptr;
839 return (func_ptr_type) obj_main->entry;
843 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
848 ptr = (void *)make_function_pointer(def, obj);
849 target = call_ifunc_resolver(ptr);
850 return ((void *)target);
854 * NB: MIPS uses a private version of this function (_mips_rtld_bind).
855 * Changes to this function should be applied there as well.
858 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
862 const Obj_Entry *defobj;
865 RtldLockState lockstate;
867 rlock_acquire(rtld_bind_lock, &lockstate);
868 if (sigsetjmp(lockstate.env, 0) != 0)
869 lock_upgrade(rtld_bind_lock, &lockstate);
871 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff);
873 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff);
875 where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
876 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
880 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
881 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
883 target = (Elf_Addr)(defobj->relocbase + def->st_value);
885 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
886 defobj->strtab + def->st_name, basename(obj->path),
887 (void *)target, basename(defobj->path));
890 * Write the new contents for the jmpslot. Note that depending on
891 * architecture, the value which we need to return back to the
892 * lazy binding trampoline may or may not be the target
893 * address. The value returned from reloc_jmpslot() is the value
894 * that the trampoline needs.
896 target = reloc_jmpslot(where, target, defobj, obj, rel);
897 lock_release(rtld_bind_lock, &lockstate);
902 * Error reporting function. Use it like printf. If formats the message
903 * into a buffer, and sets things up so that the next call to dlerror()
904 * will return the message.
907 _rtld_error(const char *fmt, ...)
909 static char buf[512];
913 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
916 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message);
920 * Return a dynamically-allocated copy of the current error message, if any.
925 return error_message == NULL ? NULL : xstrdup(error_message);
929 * Restore the current error message from a copy which was previously saved
930 * by errmsg_save(). The copy is freed.
933 errmsg_restore(char *saved_msg)
935 if (saved_msg == NULL)
936 error_message = NULL;
938 _rtld_error("%s", saved_msg);
944 basename(const char *name)
946 const char *p = strrchr(name, '/');
947 return p != NULL ? p + 1 : name;
950 static struct utsname uts;
953 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
954 const char *subst, bool may_free)
956 char *p, *p1, *res, *resp;
957 int subst_len, kw_len, subst_count, old_len, new_len;
962 * First, count the number of the keyword occurrences, to
963 * preallocate the final string.
965 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
972 * If the keyword is not found, just return.
974 * Return non-substituted string if resolution failed. We
975 * cannot do anything more reasonable, the failure mode of the
976 * caller is unresolved library anyway.
978 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
979 return (may_free ? real : xstrdup(real));
981 subst = obj->origin_path;
984 * There is indeed something to substitute. Calculate the
985 * length of the resulting string, and allocate it.
987 subst_len = strlen(subst);
988 old_len = strlen(real);
989 new_len = old_len + (subst_len - kw_len) * subst_count;
990 res = xmalloc(new_len + 1);
993 * Now, execute the substitution loop.
995 for (p = real, resp = res, *resp = '\0';;) {
998 /* Copy the prefix before keyword. */
999 memcpy(resp, p, p1 - p);
1001 /* Keyword replacement. */
1002 memcpy(resp, subst, subst_len);
1010 /* Copy to the end of string and finish. */
1018 origin_subst(Obj_Entry *obj, const char *real)
1020 char *res1, *res2, *res3, *res4;
1022 if (obj == NULL || !trust)
1023 return (xstrdup(real));
1024 if (uts.sysname[0] == '\0') {
1025 if (uname(&uts) != 0) {
1026 _rtld_error("utsname failed: %d", errno);
1030 /* __DECONST is safe here since without may_free real is unchanged */
1031 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL,
1033 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
1034 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
1035 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
1042 const char *msg = dlerror();
1045 msg = "Fatal error";
1046 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": ");
1047 rtld_fdputstr(STDERR_FILENO, msg);
1048 rtld_fdputchar(STDERR_FILENO, '\n');
1053 * Process a shared object's DYNAMIC section, and save the important
1054 * information in its Obj_Entry structure.
1057 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
1058 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
1060 const Elf_Dyn *dynp;
1061 Needed_Entry **needed_tail = &obj->needed;
1062 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
1063 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
1064 const Elf_Hashelt *hashtab;
1065 const Elf32_Word *hashval;
1066 Elf32_Word bkt, nmaskwords;
1068 int plttype = DT_REL;
1072 *dyn_runpath = NULL;
1074 obj->bind_now = false;
1075 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
1076 switch (dynp->d_tag) {
1079 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr);
1083 obj->relsize = dynp->d_un.d_val;
1087 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1091 obj->pltrel = (const Elf_Rel *)
1092 (obj->relocbase + dynp->d_un.d_ptr);
1096 obj->pltrelsize = dynp->d_un.d_val;
1100 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr);
1104 obj->relasize = dynp->d_un.d_val;
1108 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1112 plttype = dynp->d_un.d_val;
1113 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1117 obj->symtab = (const Elf_Sym *)
1118 (obj->relocbase + dynp->d_un.d_ptr);
1122 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1126 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr);
1130 obj->strsize = dynp->d_un.d_val;
1134 obj->verneed = (const Elf_Verneed *)(obj->relocbase +
1139 obj->verneednum = dynp->d_un.d_val;
1143 obj->verdef = (const Elf_Verdef *)(obj->relocbase +
1148 obj->verdefnum = dynp->d_un.d_val;
1152 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1158 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1160 obj->nbuckets = hashtab[0];
1161 obj->nchains = hashtab[1];
1162 obj->buckets = hashtab + 2;
1163 obj->chains = obj->buckets + obj->nbuckets;
1164 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1165 obj->buckets != NULL;
1171 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1173 obj->nbuckets_gnu = hashtab[0];
1174 obj->symndx_gnu = hashtab[1];
1175 nmaskwords = hashtab[2];
1176 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1177 obj->maskwords_bm_gnu = nmaskwords - 1;
1178 obj->shift2_gnu = hashtab[3];
1179 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4);
1180 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1181 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1183 /* Number of bitmask words is required to be power of 2 */
1184 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1185 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1191 Needed_Entry *nep = NEW(Needed_Entry);
1192 nep->name = dynp->d_un.d_val;
1197 needed_tail = &nep->next;
1203 Needed_Entry *nep = NEW(Needed_Entry);
1204 nep->name = dynp->d_un.d_val;
1208 *needed_filtees_tail = nep;
1209 needed_filtees_tail = &nep->next;
1215 Needed_Entry *nep = NEW(Needed_Entry);
1216 nep->name = dynp->d_un.d_val;
1220 *needed_aux_filtees_tail = nep;
1221 needed_aux_filtees_tail = &nep->next;
1226 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr);
1230 obj->textrel = true;
1234 obj->symbolic = true;
1239 * We have to wait until later to process this, because we
1240 * might not have gotten the address of the string table yet.
1250 *dyn_runpath = dynp;
1254 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1257 case DT_PREINIT_ARRAY:
1258 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1261 case DT_PREINIT_ARRAYSZ:
1262 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1266 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1269 case DT_INIT_ARRAYSZ:
1270 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1274 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1278 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1281 case DT_FINI_ARRAYSZ:
1282 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1286 * Don't process DT_DEBUG on MIPS as the dynamic section
1287 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1293 dbg("Filling in DT_DEBUG entry");
1294 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug;
1299 if (dynp->d_un.d_val & DF_ORIGIN)
1300 obj->z_origin = true;
1301 if (dynp->d_un.d_val & DF_SYMBOLIC)
1302 obj->symbolic = true;
1303 if (dynp->d_un.d_val & DF_TEXTREL)
1304 obj->textrel = true;
1305 if (dynp->d_un.d_val & DF_BIND_NOW)
1306 obj->bind_now = true;
1307 if (dynp->d_un.d_val & DF_STATIC_TLS)
1308 obj->static_tls = true;
1311 case DT_MIPS_LOCAL_GOTNO:
1312 obj->local_gotno = dynp->d_un.d_val;
1315 case DT_MIPS_SYMTABNO:
1316 obj->symtabno = dynp->d_un.d_val;
1319 case DT_MIPS_GOTSYM:
1320 obj->gotsym = dynp->d_un.d_val;
1323 case DT_MIPS_RLD_MAP:
1324 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1327 case DT_MIPS_RLD_MAP_REL:
1328 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map
1329 // section relative to the address of the tag itself.
1330 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) =
1331 (Elf_Addr) &r_debug;
1334 case DT_MIPS_PLTGOT:
1335 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase +
1342 #ifdef __powerpc64__
1343 case DT_PPC64_GLINK:
1344 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1348 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr);
1354 if (dynp->d_un.d_val & DF_1_NOOPEN)
1355 obj->z_noopen = true;
1356 if (dynp->d_un.d_val & DF_1_ORIGIN)
1357 obj->z_origin = true;
1358 if (dynp->d_un.d_val & DF_1_GLOBAL)
1359 obj->z_global = true;
1360 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1361 obj->bind_now = true;
1362 if (dynp->d_un.d_val & DF_1_NODELETE)
1363 obj->z_nodelete = true;
1364 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1365 obj->z_loadfltr = true;
1366 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1367 obj->z_interpose = true;
1368 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1369 obj->z_nodeflib = true;
1374 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1381 obj->traced = false;
1383 if (plttype == DT_RELA) {
1384 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1386 obj->pltrelasize = obj->pltrelsize;
1387 obj->pltrelsize = 0;
1390 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1391 if (obj->valid_hash_sysv)
1392 obj->dynsymcount = obj->nchains;
1393 else if (obj->valid_hash_gnu) {
1394 obj->dynsymcount = 0;
1395 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1396 if (obj->buckets_gnu[bkt] == 0)
1398 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1401 while ((*hashval++ & 1u) == 0);
1403 obj->dynsymcount += obj->symndx_gnu;
1408 obj_resolve_origin(Obj_Entry *obj)
1411 if (obj->origin_path != NULL)
1413 obj->origin_path = xmalloc(PATH_MAX);
1414 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1418 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1419 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1422 if (obj->z_origin && !obj_resolve_origin(obj))
1425 if (dyn_runpath != NULL) {
1426 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val;
1427 obj->runpath = origin_subst(obj, obj->runpath);
1428 } else if (dyn_rpath != NULL) {
1429 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val;
1430 obj->rpath = origin_subst(obj, obj->rpath);
1432 if (dyn_soname != NULL)
1433 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1438 digest_dynamic(Obj_Entry *obj, int early)
1440 const Elf_Dyn *dyn_rpath;
1441 const Elf_Dyn *dyn_soname;
1442 const Elf_Dyn *dyn_runpath;
1444 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1445 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath));
1449 * Process a shared object's program header. This is used only for the
1450 * main program, when the kernel has already loaded the main program
1451 * into memory before calling the dynamic linker. It creates and
1452 * returns an Obj_Entry structure.
1455 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1458 const Elf_Phdr *phlimit = phdr + phnum;
1460 Elf_Addr note_start, note_end;
1464 for (ph = phdr; ph < phlimit; ph++) {
1465 if (ph->p_type != PT_PHDR)
1469 obj->phsize = ph->p_memsz;
1470 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr;
1474 obj->stack_flags = PF_X | PF_R | PF_W;
1476 for (ph = phdr; ph < phlimit; ph++) {
1477 switch (ph->p_type) {
1480 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1484 if (nsegs == 0) { /* First load segment */
1485 obj->vaddrbase = trunc_page(ph->p_vaddr);
1486 obj->mapbase = obj->vaddrbase + obj->relocbase;
1487 } else { /* Last load segment */
1488 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1495 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1500 obj->tlssize = ph->p_memsz;
1501 obj->tlsalign = ph->p_align;
1502 obj->tlsinitsize = ph->p_filesz;
1503 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1507 obj->stack_flags = ph->p_flags;
1511 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1512 obj->relro_size = round_page(ph->p_memsz);
1516 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1517 note_end = note_start + ph->p_filesz;
1518 digest_notes(obj, note_start, note_end);
1523 _rtld_error("%s: too few PT_LOAD segments", path);
1532 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1534 const Elf_Note *note;
1535 const char *note_name;
1538 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1539 note = (const Elf_Note *)((const char *)(note + 1) +
1540 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1541 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1542 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1543 note->n_descsz != sizeof(int32_t))
1545 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1546 note->n_type != NT_FREEBSD_FEATURE_CTL &&
1547 note->n_type != NT_FREEBSD_NOINIT_TAG)
1549 note_name = (const char *)(note + 1);
1550 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1551 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1553 switch (note->n_type) {
1554 case NT_FREEBSD_ABI_TAG:
1555 /* FreeBSD osrel note */
1556 p = (uintptr_t)(note + 1);
1557 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1558 obj->osrel = *(const int32_t *)(p);
1559 dbg("note osrel %d", obj->osrel);
1561 case NT_FREEBSD_FEATURE_CTL:
1562 /* FreeBSD ABI feature control note */
1563 p = (uintptr_t)(note + 1);
1564 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1565 obj->fctl0 = *(const uint32_t *)(p);
1566 dbg("note fctl0 %#x", obj->fctl0);
1568 case NT_FREEBSD_NOINIT_TAG:
1569 /* FreeBSD 'crt does not call init' note */
1570 obj->crt_no_init = true;
1571 dbg("note crt_no_init");
1578 dlcheck(void *handle)
1582 TAILQ_FOREACH(obj, &obj_list, next) {
1583 if (obj == (Obj_Entry *) handle)
1587 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1588 _rtld_error("Invalid shared object handle %p", handle);
1595 * If the given object is already in the donelist, return true. Otherwise
1596 * add the object to the list and return false.
1599 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1603 for (i = 0; i < dlp->num_used; i++)
1604 if (dlp->objs[i] == obj)
1607 * Our donelist allocation should always be sufficient. But if
1608 * our threads locking isn't working properly, more shared objects
1609 * could have been loaded since we allocated the list. That should
1610 * never happen, but we'll handle it properly just in case it does.
1612 if (dlp->num_used < dlp->num_alloc)
1613 dlp->objs[dlp->num_used++] = obj;
1618 * Hash function for symbol table lookup. Don't even think about changing
1619 * this. It is specified by the System V ABI.
1622 elf_hash(const char *name)
1624 const unsigned char *p = (const unsigned char *) name;
1625 unsigned long h = 0;
1628 while (*p != '\0') {
1629 h = (h << 4) + *p++;
1630 if ((g = h & 0xf0000000) != 0)
1638 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1639 * unsigned in case it's implemented with a wider type.
1642 gnu_hash(const char *s)
1648 for (c = *s; c != '\0'; c = *++s)
1650 return (h & 0xffffffff);
1655 * Find the library with the given name, and return its full pathname.
1656 * The returned string is dynamically allocated. Generates an error
1657 * message and returns NULL if the library cannot be found.
1659 * If the second argument is non-NULL, then it refers to an already-
1660 * loaded shared object, whose library search path will be searched.
1662 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1663 * descriptor (which is close-on-exec) will be passed out via the third
1666 * The search order is:
1667 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1668 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1670 * DT_RUNPATH in the referencing file
1671 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1673 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1675 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1678 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1680 char *pathname, *refobj_path;
1682 bool nodeflib, objgiven;
1684 objgiven = refobj != NULL;
1686 if (libmap_disable || !objgiven ||
1687 (name = lm_find(refobj->path, xname)) == NULL)
1690 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1691 if (name[0] != '/' && !trust) {
1692 _rtld_error("Absolute pathname required "
1693 "for shared object \"%s\"", name);
1696 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1697 __DECONST(char *, name)));
1700 dbg(" Searching for \"%s\"", name);
1701 refobj_path = objgiven ? refobj->path : NULL;
1704 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1705 * back to pre-conforming behaviour if user requested so with
1706 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1709 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1710 pathname = search_library_path(name, ld_library_path,
1712 if (pathname != NULL)
1714 if (refobj != NULL) {
1715 pathname = search_library_path(name, refobj->rpath,
1717 if (pathname != NULL)
1720 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1721 if (pathname != NULL)
1723 pathname = search_library_path(name, gethints(false),
1725 if (pathname != NULL)
1727 pathname = search_library_path(name, ld_standard_library_path,
1729 if (pathname != NULL)
1732 nodeflib = objgiven ? refobj->z_nodeflib : false;
1734 pathname = search_library_path(name, refobj->rpath,
1736 if (pathname != NULL)
1739 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1740 pathname = search_library_path(name, obj_main->rpath,
1742 if (pathname != NULL)
1745 pathname = search_library_path(name, ld_library_path,
1747 if (pathname != NULL)
1750 pathname = search_library_path(name, refobj->runpath,
1752 if (pathname != NULL)
1755 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1756 if (pathname != NULL)
1758 pathname = search_library_path(name, gethints(nodeflib),
1760 if (pathname != NULL)
1762 if (objgiven && !nodeflib) {
1763 pathname = search_library_path(name,
1764 ld_standard_library_path, refobj_path, fdp);
1765 if (pathname != NULL)
1770 if (objgiven && refobj->path != NULL) {
1771 _rtld_error("Shared object \"%s\" not found, "
1772 "required by \"%s\"", name, basename(refobj->path));
1774 _rtld_error("Shared object \"%s\" not found", name);
1780 * Given a symbol number in a referencing object, find the corresponding
1781 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1782 * no definition was found. Returns a pointer to the Obj_Entry of the
1783 * defining object via the reference parameter DEFOBJ_OUT.
1786 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1787 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1788 RtldLockState *lockstate)
1792 const Obj_Entry *defobj;
1793 const Ver_Entry *ve;
1799 * If we have already found this symbol, get the information from
1802 if (symnum >= refobj->dynsymcount)
1803 return NULL; /* Bad object */
1804 if (cache != NULL && cache[symnum].sym != NULL) {
1805 *defobj_out = cache[symnum].obj;
1806 return cache[symnum].sym;
1809 ref = refobj->symtab + symnum;
1810 name = refobj->strtab + ref->st_name;
1816 * We don't have to do a full scale lookup if the symbol is local.
1817 * We know it will bind to the instance in this load module; to
1818 * which we already have a pointer (ie ref). By not doing a lookup,
1819 * we not only improve performance, but it also avoids unresolvable
1820 * symbols when local symbols are not in the hash table. This has
1821 * been seen with the ia64 toolchain.
1823 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1824 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1825 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1828 symlook_init(&req, name);
1830 ve = req.ventry = fetch_ventry(refobj, symnum);
1831 req.lockstate = lockstate;
1832 res = symlook_default(&req, refobj);
1835 defobj = req.defobj_out;
1843 * If we found no definition and the reference is weak, treat the
1844 * symbol as having the value zero.
1846 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1852 *defobj_out = defobj;
1853 /* Record the information in the cache to avoid subsequent lookups. */
1854 if (cache != NULL) {
1855 cache[symnum].sym = def;
1856 cache[symnum].obj = defobj;
1859 if (refobj != &obj_rtld)
1860 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name,
1861 ve != NULL ? "@" : "", ve != NULL ? ve->name : "");
1867 * Return the search path from the ldconfig hints file, reading it if
1868 * necessary. If nostdlib is true, then the default search paths are
1869 * not added to result.
1871 * Returns NULL if there are problems with the hints file,
1872 * or if the search path there is empty.
1875 gethints(bool nostdlib)
1877 static char *filtered_path;
1878 static const char *hints;
1879 static struct elfhints_hdr hdr;
1880 struct fill_search_info_args sargs, hargs;
1881 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1882 struct dl_serpath *SLPpath, *hintpath;
1884 struct stat hint_stat;
1885 unsigned int SLPndx, hintndx, fndx, fcount;
1891 /* First call, read the hints file */
1892 if (hints == NULL) {
1893 /* Keep from trying again in case the hints file is bad. */
1896 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1900 * Check of hdr.dirlistlen value against type limit
1901 * intends to pacify static analyzers. Further
1902 * paranoia leads to checks that dirlist is fully
1903 * contained in the file range.
1905 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1906 hdr.magic != ELFHINTS_MAGIC ||
1907 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 ||
1908 fstat(fd, &hint_stat) == -1) {
1915 if (dl + hdr.dirlist < dl)
1918 if (dl + hdr.dirlistlen < dl)
1920 dl += hdr.dirlistlen;
1921 if (dl > hint_stat.st_size)
1923 p = xmalloc(hdr.dirlistlen + 1);
1924 if (pread(fd, p, hdr.dirlistlen + 1,
1925 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 ||
1926 p[hdr.dirlistlen] != '\0') {
1935 * If caller agreed to receive list which includes the default
1936 * paths, we are done. Otherwise, if we still did not
1937 * calculated filtered result, do it now.
1940 return (hints[0] != '\0' ? hints : NULL);
1941 if (filtered_path != NULL)
1945 * Obtain the list of all configured search paths, and the
1946 * list of the default paths.
1948 * First estimate the size of the results.
1950 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1952 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1955 sargs.request = RTLD_DI_SERINFOSIZE;
1956 sargs.serinfo = &smeta;
1957 hargs.request = RTLD_DI_SERINFOSIZE;
1958 hargs.serinfo = &hmeta;
1960 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1962 path_enumerate(hints, fill_search_info, NULL, &hargs);
1964 SLPinfo = xmalloc(smeta.dls_size);
1965 hintinfo = xmalloc(hmeta.dls_size);
1968 * Next fetch both sets of paths.
1970 sargs.request = RTLD_DI_SERINFO;
1971 sargs.serinfo = SLPinfo;
1972 sargs.serpath = &SLPinfo->dls_serpath[0];
1973 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1975 hargs.request = RTLD_DI_SERINFO;
1976 hargs.serinfo = hintinfo;
1977 hargs.serpath = &hintinfo->dls_serpath[0];
1978 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1980 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1982 path_enumerate(hints, fill_search_info, NULL, &hargs);
1985 * Now calculate the difference between two sets, by excluding
1986 * standard paths from the full set.
1990 filtered_path = xmalloc(hdr.dirlistlen + 1);
1991 hintpath = &hintinfo->dls_serpath[0];
1992 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1994 SLPpath = &SLPinfo->dls_serpath[0];
1996 * Check each standard path against current.
1998 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1999 /* matched, skip the path */
2000 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
2008 * Not matched against any standard path, add the path
2009 * to result. Separate consequtive paths with ':'.
2012 filtered_path[fndx] = ':';
2016 flen = strlen(hintpath->dls_name);
2017 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
2020 filtered_path[fndx] = '\0';
2026 return (filtered_path[0] != '\0' ? filtered_path : NULL);
2030 init_dag(Obj_Entry *root)
2032 const Needed_Entry *needed;
2033 const Objlist_Entry *elm;
2036 if (root->dag_inited)
2038 donelist_init(&donelist);
2040 /* Root object belongs to own DAG. */
2041 objlist_push_tail(&root->dldags, root);
2042 objlist_push_tail(&root->dagmembers, root);
2043 donelist_check(&donelist, root);
2046 * Add dependencies of root object to DAG in breadth order
2047 * by exploiting the fact that each new object get added
2048 * to the tail of the dagmembers list.
2050 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2051 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
2052 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
2054 objlist_push_tail(&needed->obj->dldags, root);
2055 objlist_push_tail(&root->dagmembers, needed->obj);
2058 root->dag_inited = true;
2062 init_marker(Obj_Entry *marker)
2065 bzero(marker, sizeof(*marker));
2066 marker->marker = true;
2070 globallist_curr(const Obj_Entry *obj)
2077 return (__DECONST(Obj_Entry *, obj));
2078 obj = TAILQ_PREV(obj, obj_entry_q, next);
2083 globallist_next(const Obj_Entry *obj)
2087 obj = TAILQ_NEXT(obj, next);
2091 return (__DECONST(Obj_Entry *, obj));
2095 /* Prevent the object from being unmapped while the bind lock is dropped. */
2097 hold_object(Obj_Entry *obj)
2104 unhold_object(Obj_Entry *obj)
2107 assert(obj->holdcount > 0);
2108 if (--obj->holdcount == 0 && obj->unholdfree)
2109 release_object(obj);
2113 process_z(Obj_Entry *root)
2115 const Objlist_Entry *elm;
2119 * Walk over object DAG and process every dependent object
2120 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2121 * to grow their own DAG.
2123 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2124 * symlook_global() to work.
2126 * For DF_1_NODELETE, the DAG should have its reference upped.
2128 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2132 if (obj->z_nodelete && !obj->ref_nodel) {
2133 dbg("obj %s -z nodelete", obj->path);
2136 obj->ref_nodel = true;
2138 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2139 dbg("obj %s -z global", obj->path);
2140 objlist_push_tail(&list_global, obj);
2146 * Initialize the dynamic linker. The argument is the address at which
2147 * the dynamic linker has been mapped into memory. The primary task of
2148 * this function is to relocate the dynamic linker.
2151 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2153 Obj_Entry objtmp; /* Temporary rtld object */
2154 const Elf_Ehdr *ehdr;
2155 const Elf_Dyn *dyn_rpath;
2156 const Elf_Dyn *dyn_soname;
2157 const Elf_Dyn *dyn_runpath;
2159 #ifdef RTLD_INIT_PAGESIZES_EARLY
2160 /* The page size is required by the dynamic memory allocator. */
2161 init_pagesizes(aux_info);
2165 * Conjure up an Obj_Entry structure for the dynamic linker.
2167 * The "path" member can't be initialized yet because string constants
2168 * cannot yet be accessed. Below we will set it correctly.
2170 memset(&objtmp, 0, sizeof(objtmp));
2173 objtmp.mapbase = mapbase;
2175 objtmp.relocbase = mapbase;
2178 objtmp.dynamic = rtld_dynamic(&objtmp);
2179 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2180 assert(objtmp.needed == NULL);
2181 #if !defined(__mips__)
2182 /* MIPS has a bogus DT_TEXTREL. */
2183 assert(!objtmp.textrel);
2186 * Temporarily put the dynamic linker entry into the object list, so
2187 * that symbols can be found.
2189 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2191 ehdr = (Elf_Ehdr *)mapbase;
2192 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2193 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]);
2195 /* Initialize the object list. */
2196 TAILQ_INIT(&obj_list);
2198 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2199 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2201 #ifndef RTLD_INIT_PAGESIZES_EARLY
2202 /* The page size is required by the dynamic memory allocator. */
2203 init_pagesizes(aux_info);
2206 if (aux_info[AT_OSRELDATE] != NULL)
2207 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2209 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2211 /* Replace the path with a dynamically allocated copy. */
2212 obj_rtld.path = xstrdup(ld_path_rtld);
2214 r_debug.r_brk = r_debug_state;
2215 r_debug.r_state = RT_CONSISTENT;
2219 * Retrieve the array of supported page sizes. The kernel provides the page
2220 * sizes in increasing order.
2223 init_pagesizes(Elf_Auxinfo **aux_info)
2225 static size_t psa[MAXPAGESIZES];
2229 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
2231 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2232 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2235 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2238 /* As a fallback, retrieve the base page size. */
2239 size = sizeof(psa[0]);
2240 if (aux_info[AT_PAGESZ] != NULL) {
2241 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2245 mib[1] = HW_PAGESIZE;
2249 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2250 _rtld_error("sysctl for hw.pagesize(s) failed");
2256 npagesizes = size / sizeof(pagesizes[0]);
2257 /* Discard any invalid entries at the end of the array. */
2258 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2263 * Add the init functions from a needed object list (and its recursive
2264 * needed objects) to "list". This is not used directly; it is a helper
2265 * function for initlist_add_objects(). The write lock must be held
2266 * when this function is called.
2269 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
2271 /* Recursively process the successor needed objects. */
2272 if (needed->next != NULL)
2273 initlist_add_neededs(needed->next, list);
2275 /* Process the current needed object. */
2276 if (needed->obj != NULL)
2277 initlist_add_objects(needed->obj, needed->obj, list);
2281 * Scan all of the DAGs rooted in the range of objects from "obj" to
2282 * "tail" and add their init functions to "list". This recurses over
2283 * the DAGs and ensure the proper init ordering such that each object's
2284 * needed libraries are initialized before the object itself. At the
2285 * same time, this function adds the objects to the global finalization
2286 * list "list_fini" in the opposite order. The write lock must be
2287 * held when this function is called.
2290 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2294 if (obj->init_scanned || obj->init_done)
2296 obj->init_scanned = true;
2298 /* Recursively process the successor objects. */
2299 nobj = globallist_next(obj);
2300 if (nobj != NULL && obj != tail)
2301 initlist_add_objects(nobj, tail, list);
2303 /* Recursively process the needed objects. */
2304 if (obj->needed != NULL)
2305 initlist_add_neededs(obj->needed, list);
2306 if (obj->needed_filtees != NULL)
2307 initlist_add_neededs(obj->needed_filtees, list);
2308 if (obj->needed_aux_filtees != NULL)
2309 initlist_add_neededs(obj->needed_aux_filtees, list);
2311 /* Add the object to the init list. */
2312 objlist_push_tail(list, obj);
2314 /* Add the object to the global fini list in the reverse order. */
2315 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2316 && !obj->on_fini_list) {
2317 objlist_push_head(&list_fini, obj);
2318 obj->on_fini_list = true;
2323 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2327 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2329 Needed_Entry *needed, *needed1;
2331 for (needed = n; needed != NULL; needed = needed->next) {
2332 if (needed->obj != NULL) {
2333 dlclose_locked(needed->obj, lockstate);
2337 for (needed = n; needed != NULL; needed = needed1) {
2338 needed1 = needed->next;
2344 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2347 free_needed_filtees(obj->needed_filtees, lockstate);
2348 obj->needed_filtees = NULL;
2349 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2350 obj->needed_aux_filtees = NULL;
2351 obj->filtees_loaded = false;
2355 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2356 RtldLockState *lockstate)
2359 for (; needed != NULL; needed = needed->next) {
2360 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2361 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2362 RTLD_LOCAL, lockstate);
2367 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2370 lock_restart_for_upgrade(lockstate);
2371 if (!obj->filtees_loaded) {
2372 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2373 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2374 obj->filtees_loaded = true;
2379 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2383 for (; needed != NULL; needed = needed->next) {
2384 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2385 flags & ~RTLD_LO_NOLOAD);
2386 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2393 * Given a shared object, traverse its list of needed objects, and load
2394 * each of them. Returns 0 on success. Generates an error message and
2395 * returns -1 on failure.
2398 load_needed_objects(Obj_Entry *first, int flags)
2402 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2405 if (process_needed(obj, obj->needed, flags) == -1)
2412 load_preload_objects(void)
2414 char *p = ld_preload;
2416 static const char delim[] = " \t:;";
2421 p += strspn(p, delim);
2422 while (*p != '\0') {
2423 size_t len = strcspn(p, delim);
2428 obj = load_object(p, -1, NULL, 0);
2430 return -1; /* XXX - cleanup */
2431 obj->z_interpose = true;
2434 p += strspn(p, delim);
2436 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2441 printable_path(const char *path)
2444 return (path == NULL ? "<unknown>" : path);
2448 * Load a shared object into memory, if it is not already loaded. The
2449 * object may be specified by name or by user-supplied file descriptor
2450 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2453 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2457 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2466 TAILQ_FOREACH(obj, &obj_list, next) {
2467 if (obj->marker || obj->doomed)
2469 if (object_match_name(obj, name))
2473 path = find_library(name, refobj, &fd);
2481 * search_library_pathfds() opens a fresh file descriptor for the
2482 * library, so there is no need to dup().
2484 } else if (fd_u == -1) {
2486 * If we didn't find a match by pathname, or the name is not
2487 * supplied, open the file and check again by device and inode.
2488 * This avoids false mismatches caused by multiple links or ".."
2491 * To avoid a race, we open the file and use fstat() rather than
2494 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2495 _rtld_error("Cannot open \"%s\"", path);
2500 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2502 _rtld_error("Cannot dup fd");
2507 if (fstat(fd, &sb) == -1) {
2508 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2513 TAILQ_FOREACH(obj, &obj_list, next) {
2514 if (obj->marker || obj->doomed)
2516 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2519 if (obj != NULL && name != NULL) {
2520 object_add_name(obj, name);
2525 if (flags & RTLD_LO_NOLOAD) {
2531 /* First use of this object, so we must map it in */
2532 obj = do_load_object(fd, name, path, &sb, flags);
2541 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2548 * but first, make sure that environment variables haven't been
2549 * used to circumvent the noexec flag on a filesystem.
2551 if (dangerous_ld_env) {
2552 if (fstatfs(fd, &fs) != 0) {
2553 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2556 if (fs.f_flags & MNT_NOEXEC) {
2557 _rtld_error("Cannot execute objects on %s", fs.f_mntonname);
2561 dbg("loading \"%s\"", printable_path(path));
2562 obj = map_object(fd, printable_path(path), sbp);
2567 * If DT_SONAME is present in the object, digest_dynamic2 already
2568 * added it to the object names.
2571 object_add_name(obj, name);
2573 if (!digest_dynamic(obj, 0))
2575 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2576 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2577 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2579 dbg("refusing to load non-loadable \"%s\"", obj->path);
2580 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2584 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2585 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2588 linkmap_add(obj); /* for GDB & dlinfo() */
2589 max_stack_flags |= obj->stack_flags;
2591 dbg(" %p .. %p: %s", obj->mapbase,
2592 obj->mapbase + obj->mapsize - 1, obj->path);
2594 dbg(" WARNING: %s has impure text", obj->path);
2595 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2601 munmap(obj->mapbase, obj->mapsize);
2607 obj_from_addr(const void *addr)
2611 TAILQ_FOREACH(obj, &obj_list, next) {
2614 if (addr < (void *) obj->mapbase)
2616 if (addr < (void *)(obj->mapbase + obj->mapsize))
2625 Elf_Addr *preinit_addr;
2628 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2629 if (preinit_addr == NULL)
2632 for (index = 0; index < obj_main->preinit_array_num; index++) {
2633 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2634 dbg("calling preinit function for %s at %p", obj_main->path,
2635 (void *)preinit_addr[index]);
2636 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2637 0, 0, obj_main->path);
2638 call_init_pointer(obj_main, preinit_addr[index]);
2644 * Call the finalization functions for each of the objects in "list"
2645 * belonging to the DAG of "root" and referenced once. If NULL "root"
2646 * is specified, every finalization function will be called regardless
2647 * of the reference count and the list elements won't be freed. All of
2648 * the objects are expected to have non-NULL fini functions.
2651 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2655 Elf_Addr *fini_addr;
2658 assert(root == NULL || root->refcount == 1);
2661 root->doomed = true;
2664 * Preserve the current error message since a fini function might
2665 * call into the dynamic linker and overwrite it.
2667 saved_msg = errmsg_save();
2669 STAILQ_FOREACH(elm, list, link) {
2670 if (root != NULL && (elm->obj->refcount != 1 ||
2671 objlist_find(&root->dagmembers, elm->obj) == NULL))
2673 /* Remove object from fini list to prevent recursive invocation. */
2674 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2675 /* Ensure that new references cannot be acquired. */
2676 elm->obj->doomed = true;
2678 hold_object(elm->obj);
2679 lock_release(rtld_bind_lock, lockstate);
2681 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2682 * When this happens, DT_FINI_ARRAY is processed first.
2684 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2685 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2686 for (index = elm->obj->fini_array_num - 1; index >= 0;
2688 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2689 dbg("calling fini function for %s at %p",
2690 elm->obj->path, (void *)fini_addr[index]);
2691 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2692 (void *)fini_addr[index], 0, 0, elm->obj->path);
2693 call_initfini_pointer(elm->obj, fini_addr[index]);
2697 if (elm->obj->fini != (Elf_Addr)NULL) {
2698 dbg("calling fini function for %s at %p", elm->obj->path,
2699 (void *)elm->obj->fini);
2700 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2701 0, 0, elm->obj->path);
2702 call_initfini_pointer(elm->obj, elm->obj->fini);
2704 wlock_acquire(rtld_bind_lock, lockstate);
2705 unhold_object(elm->obj);
2706 /* No need to free anything if process is going down. */
2710 * We must restart the list traversal after every fini call
2711 * because a dlclose() call from the fini function or from
2712 * another thread might have modified the reference counts.
2716 } while (elm != NULL);
2717 errmsg_restore(saved_msg);
2721 * Call the initialization functions for each of the objects in
2722 * "list". All of the objects are expected to have non-NULL init
2726 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2731 Elf_Addr *init_addr;
2732 void (*reg)(void (*)(void));
2736 * Clean init_scanned flag so that objects can be rechecked and
2737 * possibly initialized earlier if any of vectors called below
2738 * cause the change by using dlopen.
2740 TAILQ_FOREACH(obj, &obj_list, next) {
2743 obj->init_scanned = false;
2747 * Preserve the current error message since an init function might
2748 * call into the dynamic linker and overwrite it.
2750 saved_msg = errmsg_save();
2751 STAILQ_FOREACH(elm, list, link) {
2752 if (elm->obj->init_done) /* Initialized early. */
2755 * Race: other thread might try to use this object before current
2756 * one completes the initialization. Not much can be done here
2757 * without better locking.
2759 elm->obj->init_done = true;
2760 hold_object(elm->obj);
2762 if (elm->obj == obj_main && obj_main->crt_no_init) {
2763 reg = (void (*)(void (*)(void)))get_program_var_addr(
2764 "__libc_atexit", lockstate);
2766 lock_release(rtld_bind_lock, lockstate);
2769 rtld_exit_ptr = rtld_nop_exit;
2773 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2774 * When this happens, DT_INIT is processed first.
2776 if (elm->obj->init != (Elf_Addr)NULL) {
2777 dbg("calling init function for %s at %p", elm->obj->path,
2778 (void *)elm->obj->init);
2779 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2780 0, 0, elm->obj->path);
2781 call_initfini_pointer(elm->obj, elm->obj->init);
2783 init_addr = (Elf_Addr *)elm->obj->init_array;
2784 if (init_addr != NULL) {
2785 for (index = 0; index < elm->obj->init_array_num; index++) {
2786 if (init_addr[index] != 0 && init_addr[index] != 1) {
2787 dbg("calling init function for %s at %p", elm->obj->path,
2788 (void *)init_addr[index]);
2789 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2790 (void *)init_addr[index], 0, 0, elm->obj->path);
2791 call_init_pointer(elm->obj, init_addr[index]);
2795 wlock_acquire(rtld_bind_lock, lockstate);
2796 unhold_object(elm->obj);
2798 errmsg_restore(saved_msg);
2802 objlist_clear(Objlist *list)
2806 while (!STAILQ_EMPTY(list)) {
2807 elm = STAILQ_FIRST(list);
2808 STAILQ_REMOVE_HEAD(list, link);
2813 static Objlist_Entry *
2814 objlist_find(Objlist *list, const Obj_Entry *obj)
2818 STAILQ_FOREACH(elm, list, link)
2819 if (elm->obj == obj)
2825 objlist_init(Objlist *list)
2831 objlist_push_head(Objlist *list, Obj_Entry *obj)
2835 elm = NEW(Objlist_Entry);
2837 STAILQ_INSERT_HEAD(list, elm, link);
2841 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2845 elm = NEW(Objlist_Entry);
2847 STAILQ_INSERT_TAIL(list, elm, link);
2851 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2853 Objlist_Entry *elm, *listelm;
2855 STAILQ_FOREACH(listelm, list, link) {
2856 if (listelm->obj == listobj)
2859 elm = NEW(Objlist_Entry);
2861 if (listelm != NULL)
2862 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2864 STAILQ_INSERT_TAIL(list, elm, link);
2868 objlist_remove(Objlist *list, Obj_Entry *obj)
2872 if ((elm = objlist_find(list, obj)) != NULL) {
2873 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2879 * Relocate dag rooted in the specified object.
2880 * Returns 0 on success, or -1 on failure.
2884 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2885 int flags, RtldLockState *lockstate)
2891 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2892 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2901 * Prepare for, or clean after, relocating an object marked with
2902 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
2903 * segments are remapped read-write. After relocations are done, the
2904 * segment's permissions are returned back to the modes specified in
2905 * the phdrs. If any relocation happened, or always for wired
2906 * program, COW is triggered.
2909 reloc_textrel_prot(Obj_Entry *obj, bool before)
2916 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
2918 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
2920 base = obj->relocbase + trunc_page(ph->p_vaddr);
2921 sz = round_page(ph->p_vaddr + ph->p_filesz) -
2922 trunc_page(ph->p_vaddr);
2923 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0);
2924 if (mprotect(base, sz, prot) == -1) {
2925 _rtld_error("%s: Cannot write-%sable text segment: %s",
2926 obj->path, before ? "en" : "dis",
2927 rtld_strerror(errno));
2935 * Relocate single object.
2936 * Returns 0 on success, or -1 on failure.
2939 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2940 int flags, RtldLockState *lockstate)
2945 obj->relocated = true;
2947 dbg("relocating \"%s\"", obj->path);
2949 if (obj->symtab == NULL || obj->strtab == NULL ||
2950 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2951 _rtld_error("%s: Shared object has no run-time symbol table",
2956 /* There are relocations to the write-protected text segment. */
2957 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
2960 /* Process the non-PLT non-IFUNC relocations. */
2961 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2964 /* Re-protected the text segment. */
2965 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
2968 /* Set the special PLT or GOT entries. */
2971 /* Process the PLT relocations. */
2972 if (reloc_plt(obj, flags, lockstate) == -1)
2974 /* Relocate the jump slots if we are doing immediate binding. */
2975 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags,
2979 if (!obj->mainprog && obj_enforce_relro(obj) == -1)
2983 * Set up the magic number and version in the Obj_Entry. These
2984 * were checked in the crt1.o from the original ElfKit, so we
2985 * set them for backward compatibility.
2987 obj->magic = RTLD_MAGIC;
2988 obj->version = RTLD_VERSION;
2994 * Relocate newly-loaded shared objects. The argument is a pointer to
2995 * the Obj_Entry for the first such object. All objects from the first
2996 * to the end of the list of objects are relocated. Returns 0 on success,
3000 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
3001 int flags, RtldLockState *lockstate)
3006 for (error = 0, obj = first; obj != NULL;
3007 obj = TAILQ_NEXT(obj, next)) {
3010 error = relocate_object(obj, bind_now, rtldobj, flags,
3019 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
3020 * referencing STT_GNU_IFUNC symbols is postponed till the other
3021 * relocations are done. The indirect functions specified as
3022 * ifunc are allowed to call other symbols, so we need to have
3023 * objects relocated before asking for resolution from indirects.
3025 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
3026 * instead of the usual lazy handling of PLT slots. It is
3027 * consistent with how GNU does it.
3030 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
3031 RtldLockState *lockstate)
3034 if (obj->ifuncs_resolved)
3036 obj->ifuncs_resolved = true;
3037 if (!obj->irelative && !obj->irelative_nonplt &&
3038 !((obj->bind_now || bind_now) && obj->gnu_ifunc))
3040 if (obj_disable_relro(obj) == -1 ||
3041 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) ||
3042 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj,
3043 lockstate) == -1) ||
3044 ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
3045 reloc_gnu_ifunc(obj, flags, lockstate) == -1) ||
3046 obj_enforce_relro(obj) == -1)
3052 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
3053 RtldLockState *lockstate)
3058 STAILQ_FOREACH(elm, list, link) {
3062 if (resolve_object_ifunc(obj, bind_now, flags,
3070 * Cleanup procedure. It will be called (by the atexit mechanism) just
3071 * before the process exits.
3076 RtldLockState lockstate;
3078 wlock_acquire(rtld_bind_lock, &lockstate);
3080 objlist_call_fini(&list_fini, NULL, &lockstate);
3081 /* No need to remove the items from the list, since we are exiting. */
3082 if (!libmap_disable)
3084 lock_release(rtld_bind_lock, &lockstate);
3093 * Iterate over a search path, translate each element, and invoke the
3094 * callback on the result.
3097 path_enumerate(const char *path, path_enum_proc callback,
3098 const char *refobj_path, void *arg)
3104 path += strspn(path, ":;");
3105 while (*path != '\0') {
3109 len = strcspn(path, ":;");
3110 trans = lm_findn(refobj_path, path, len);
3112 res = callback(trans, strlen(trans), arg);
3114 res = callback(path, len, arg);
3120 path += strspn(path, ":;");
3126 struct try_library_args {
3135 try_library_path(const char *dir, size_t dirlen, void *param)
3137 struct try_library_args *arg;
3141 if (*dir == '/' || trust) {
3144 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3147 pathname = arg->buffer;
3148 strncpy(pathname, dir, dirlen);
3149 pathname[dirlen] = '/';
3150 strcpy(pathname + dirlen + 1, arg->name);
3152 dbg(" Trying \"%s\"", pathname);
3153 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3155 dbg(" Opened \"%s\", fd %d", pathname, fd);
3156 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3157 strcpy(pathname, arg->buffer);
3161 dbg(" Failed to open \"%s\": %s",
3162 pathname, rtld_strerror(errno));
3169 search_library_path(const char *name, const char *path,
3170 const char *refobj_path, int *fdp)
3173 struct try_library_args arg;
3179 arg.namelen = strlen(name);
3180 arg.buffer = xmalloc(PATH_MAX);
3181 arg.buflen = PATH_MAX;
3184 p = path_enumerate(path, try_library_path, refobj_path, &arg);
3194 * Finds the library with the given name using the directory descriptors
3195 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3197 * Returns a freshly-opened close-on-exec file descriptor for the library,
3198 * or -1 if the library cannot be found.
3201 search_library_pathfds(const char *name, const char *path, int *fdp)
3203 char *envcopy, *fdstr, *found, *last_token;
3207 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3209 /* Don't load from user-specified libdirs into setuid binaries. */
3213 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3217 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3218 if (name[0] == '/') {
3219 dbg("Absolute path (%s) passed to %s", name, __func__);
3224 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3225 * copy of the path, as strtok_r rewrites separator tokens
3229 envcopy = xstrdup(path);
3230 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3231 fdstr = strtok_r(NULL, ":", &last_token)) {
3232 dirfd = parse_integer(fdstr);
3234 _rtld_error("failed to parse directory FD: '%s'",
3238 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3241 len = strlen(fdstr) + strlen(name) + 3;
3242 found = xmalloc(len);
3243 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
3244 _rtld_error("error generating '%d/%s'",
3248 dbg("open('%s') => %d", found, fd);
3259 dlclose(void *handle)
3261 RtldLockState lockstate;
3264 wlock_acquire(rtld_bind_lock, &lockstate);
3265 error = dlclose_locked(handle, &lockstate);
3266 lock_release(rtld_bind_lock, &lockstate);
3271 dlclose_locked(void *handle, RtldLockState *lockstate)
3275 root = dlcheck(handle);
3278 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3281 /* Unreference the object and its dependencies. */
3282 root->dl_refcount--;
3284 if (root->refcount == 1) {
3286 * The object will be no longer referenced, so we must unload it.
3287 * First, call the fini functions.
3289 objlist_call_fini(&list_fini, root, lockstate);
3293 /* Finish cleaning up the newly-unreferenced objects. */
3294 GDB_STATE(RT_DELETE,&root->linkmap);
3295 unload_object(root, lockstate);
3296 GDB_STATE(RT_CONSISTENT,NULL);
3300 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3307 char *msg = error_message;
3308 error_message = NULL;
3313 * This function is deprecated and has no effect.
3316 dllockinit(void *context,
3317 void *(*_lock_create)(void *context) __unused,
3318 void (*_rlock_acquire)(void *lock) __unused,
3319 void (*_wlock_acquire)(void *lock) __unused,
3320 void (*_lock_release)(void *lock) __unused,
3321 void (*_lock_destroy)(void *lock) __unused,
3322 void (*context_destroy)(void *context))
3324 static void *cur_context;
3325 static void (*cur_context_destroy)(void *);
3327 /* Just destroy the context from the previous call, if necessary. */
3328 if (cur_context_destroy != NULL)
3329 cur_context_destroy(cur_context);
3330 cur_context = context;
3331 cur_context_destroy = context_destroy;
3335 dlopen(const char *name, int mode)
3338 return (rtld_dlopen(name, -1, mode));
3342 fdlopen(int fd, int mode)
3345 return (rtld_dlopen(NULL, fd, mode));
3349 rtld_dlopen(const char *name, int fd, int mode)
3351 RtldLockState lockstate;
3354 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3355 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3356 if (ld_tracing != NULL) {
3357 rlock_acquire(rtld_bind_lock, &lockstate);
3358 if (sigsetjmp(lockstate.env, 0) != 0)
3359 lock_upgrade(rtld_bind_lock, &lockstate);
3360 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate));
3361 lock_release(rtld_bind_lock, &lockstate);
3363 lo_flags = RTLD_LO_DLOPEN;
3364 if (mode & RTLD_NODELETE)
3365 lo_flags |= RTLD_LO_NODELETE;
3366 if (mode & RTLD_NOLOAD)
3367 lo_flags |= RTLD_LO_NOLOAD;
3368 if (ld_tracing != NULL)
3369 lo_flags |= RTLD_LO_TRACE;
3371 return (dlopen_object(name, fd, obj_main, lo_flags,
3372 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3376 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3381 if (obj->refcount == 0)
3382 unload_object(obj, lockstate);
3386 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3387 int mode, RtldLockState *lockstate)
3389 Obj_Entry *old_obj_tail;
3392 RtldLockState mlockstate;
3395 objlist_init(&initlist);
3397 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3398 wlock_acquire(rtld_bind_lock, &mlockstate);
3399 lockstate = &mlockstate;
3401 GDB_STATE(RT_ADD,NULL);
3403 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
3405 if (name == NULL && fd == -1) {
3409 obj = load_object(name, fd, refobj, lo_flags);
3414 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3415 objlist_push_tail(&list_global, obj);
3416 if (globallist_next(old_obj_tail) != NULL) {
3417 /* We loaded something new. */
3418 assert(globallist_next(old_obj_tail) == obj);
3420 if ((lo_flags & RTLD_LO_EARLY) == 0 && obj->static_tls &&
3421 !allocate_tls_offset(obj)) {
3422 _rtld_error("%s: No space available "
3423 "for static Thread Local Storage", obj->path);
3427 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN |
3432 result = rtld_verify_versions(&obj->dagmembers);
3433 if (result != -1 && ld_tracing)
3435 if (result == -1 || relocate_object_dag(obj,
3436 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3437 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3439 dlopen_cleanup(obj, lockstate);
3441 } else if (lo_flags & RTLD_LO_EARLY) {
3443 * Do not call the init functions for early loaded
3444 * filtees. The image is still not initialized enough
3447 * Our object is found by the global object list and
3448 * will be ordered among all init calls done right
3449 * before transferring control to main.
3452 /* Make list of init functions to call. */
3453 initlist_add_objects(obj, obj, &initlist);
3456 * Process all no_delete or global objects here, given
3457 * them own DAGs to prevent their dependencies from being
3458 * unloaded. This has to be done after we have loaded all
3459 * of the dependencies, so that we do not miss any.
3465 * Bump the reference counts for objects on this DAG. If
3466 * this is the first dlopen() call for the object that was
3467 * already loaded as a dependency, initialize the dag
3473 if ((lo_flags & RTLD_LO_TRACE) != 0)
3476 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3477 obj->z_nodelete) && !obj->ref_nodel) {
3478 dbg("obj %s nodelete", obj->path);
3480 obj->z_nodelete = obj->ref_nodel = true;
3484 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3486 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3488 if ((lo_flags & RTLD_LO_EARLY) == 0) {
3489 map_stacks_exec(lockstate);
3491 distribute_static_tls(&initlist, lockstate);
3494 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3495 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3497 objlist_clear(&initlist);
3498 dlopen_cleanup(obj, lockstate);
3499 if (lockstate == &mlockstate)
3500 lock_release(rtld_bind_lock, lockstate);
3504 if (!(lo_flags & RTLD_LO_EARLY)) {
3505 /* Call the init functions. */
3506 objlist_call_init(&initlist, lockstate);
3508 objlist_clear(&initlist);
3509 if (lockstate == &mlockstate)
3510 lock_release(rtld_bind_lock, lockstate);
3513 trace_loaded_objects(obj);
3514 if (lockstate == &mlockstate)
3515 lock_release(rtld_bind_lock, lockstate);
3520 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3524 const Obj_Entry *obj, *defobj;
3527 RtldLockState lockstate;
3534 symlook_init(&req, name);
3536 req.flags = flags | SYMLOOK_IN_PLT;
3537 req.lockstate = &lockstate;
3539 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3540 rlock_acquire(rtld_bind_lock, &lockstate);
3541 if (sigsetjmp(lockstate.env, 0) != 0)
3542 lock_upgrade(rtld_bind_lock, &lockstate);
3543 if (handle == NULL || handle == RTLD_NEXT ||
3544 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3546 if ((obj = obj_from_addr(retaddr)) == NULL) {
3547 _rtld_error("Cannot determine caller's shared object");
3548 lock_release(rtld_bind_lock, &lockstate);
3549 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3552 if (handle == NULL) { /* Just the caller's shared object. */
3553 res = symlook_obj(&req, obj);
3556 defobj = req.defobj_out;
3558 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3559 handle == RTLD_SELF) { /* ... caller included */
3560 if (handle == RTLD_NEXT)
3561 obj = globallist_next(obj);
3562 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3565 res = symlook_obj(&req, obj);
3568 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3570 defobj = req.defobj_out;
3571 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3577 * Search the dynamic linker itself, and possibly resolve the
3578 * symbol from there. This is how the application links to
3579 * dynamic linker services such as dlopen.
3581 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3582 res = symlook_obj(&req, &obj_rtld);
3585 defobj = req.defobj_out;
3589 assert(handle == RTLD_DEFAULT);
3590 res = symlook_default(&req, obj);
3592 defobj = req.defobj_out;
3597 if ((obj = dlcheck(handle)) == NULL) {
3598 lock_release(rtld_bind_lock, &lockstate);
3599 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3603 donelist_init(&donelist);
3604 if (obj->mainprog) {
3605 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3606 res = symlook_global(&req, &donelist);
3609 defobj = req.defobj_out;
3612 * Search the dynamic linker itself, and possibly resolve the
3613 * symbol from there. This is how the application links to
3614 * dynamic linker services such as dlopen.
3616 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3617 res = symlook_obj(&req, &obj_rtld);
3620 defobj = req.defobj_out;
3625 /* Search the whole DAG rooted at the given object. */
3626 res = symlook_list(&req, &obj->dagmembers, &donelist);
3629 defobj = req.defobj_out;
3635 lock_release(rtld_bind_lock, &lockstate);
3638 * The value required by the caller is derived from the value
3639 * of the symbol. this is simply the relocated value of the
3642 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3643 sym = make_function_pointer(def, defobj);
3644 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3645 sym = rtld_resolve_ifunc(defobj, def);
3646 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3647 ti.ti_module = defobj->tlsindex;
3648 ti.ti_offset = def->st_value;
3649 sym = __tls_get_addr(&ti);
3651 sym = defobj->relocbase + def->st_value;
3652 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3656 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
3657 ve != NULL ? ve->name : "");
3658 lock_release(rtld_bind_lock, &lockstate);
3659 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3664 dlsym(void *handle, const char *name)
3666 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3671 dlfunc(void *handle, const char *name)
3678 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3684 dlvsym(void *handle, const char *name, const char *version)
3688 ventry.name = version;
3690 ventry.hash = elf_hash(version);
3692 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3697 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3699 const Obj_Entry *obj;
3700 RtldLockState lockstate;
3702 rlock_acquire(rtld_bind_lock, &lockstate);
3703 obj = obj_from_addr(addr);
3705 _rtld_error("No shared object contains address");
3706 lock_release(rtld_bind_lock, &lockstate);
3709 rtld_fill_dl_phdr_info(obj, phdr_info);
3710 lock_release(rtld_bind_lock, &lockstate);
3715 dladdr(const void *addr, Dl_info *info)
3717 const Obj_Entry *obj;
3720 unsigned long symoffset;
3721 RtldLockState lockstate;
3723 rlock_acquire(rtld_bind_lock, &lockstate);
3724 obj = obj_from_addr(addr);
3726 _rtld_error("No shared object contains address");
3727 lock_release(rtld_bind_lock, &lockstate);
3730 info->dli_fname = obj->path;
3731 info->dli_fbase = obj->mapbase;
3732 info->dli_saddr = (void *)0;
3733 info->dli_sname = NULL;
3736 * Walk the symbol list looking for the symbol whose address is
3737 * closest to the address sent in.
3739 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3740 def = obj->symtab + symoffset;
3743 * For skip the symbol if st_shndx is either SHN_UNDEF or
3746 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3750 * If the symbol is greater than the specified address, or if it
3751 * is further away from addr than the current nearest symbol,
3754 symbol_addr = obj->relocbase + def->st_value;
3755 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3758 /* Update our idea of the nearest symbol. */
3759 info->dli_sname = obj->strtab + def->st_name;
3760 info->dli_saddr = symbol_addr;
3763 if (info->dli_saddr == addr)
3766 lock_release(rtld_bind_lock, &lockstate);
3771 dlinfo(void *handle, int request, void *p)
3773 const Obj_Entry *obj;
3774 RtldLockState lockstate;
3777 rlock_acquire(rtld_bind_lock, &lockstate);
3779 if (handle == NULL || handle == RTLD_SELF) {
3782 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3783 if ((obj = obj_from_addr(retaddr)) == NULL)
3784 _rtld_error("Cannot determine caller's shared object");
3786 obj = dlcheck(handle);
3789 lock_release(rtld_bind_lock, &lockstate);
3795 case RTLD_DI_LINKMAP:
3796 *((struct link_map const **)p) = &obj->linkmap;
3798 case RTLD_DI_ORIGIN:
3799 error = rtld_dirname(obj->path, p);
3802 case RTLD_DI_SERINFOSIZE:
3803 case RTLD_DI_SERINFO:
3804 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3808 _rtld_error("Invalid request %d passed to dlinfo()", request);
3812 lock_release(rtld_bind_lock, &lockstate);
3818 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3821 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3822 phdr_info->dlpi_name = obj->path;
3823 phdr_info->dlpi_phdr = obj->phdr;
3824 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3825 phdr_info->dlpi_tls_modid = obj->tlsindex;
3826 phdr_info->dlpi_tls_data = obj->tlsinit;
3827 phdr_info->dlpi_adds = obj_loads;
3828 phdr_info->dlpi_subs = obj_loads - obj_count;
3832 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3834 struct dl_phdr_info phdr_info;
3835 Obj_Entry *obj, marker;
3836 RtldLockState bind_lockstate, phdr_lockstate;
3839 init_marker(&marker);
3842 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3843 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3844 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
3845 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
3846 rtld_fill_dl_phdr_info(obj, &phdr_info);
3848 lock_release(rtld_bind_lock, &bind_lockstate);
3850 error = callback(&phdr_info, sizeof phdr_info, param);
3852 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3854 obj = globallist_next(&marker);
3855 TAILQ_REMOVE(&obj_list, &marker, next);
3857 lock_release(rtld_bind_lock, &bind_lockstate);
3858 lock_release(rtld_phdr_lock, &phdr_lockstate);
3864 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3865 lock_release(rtld_bind_lock, &bind_lockstate);
3866 error = callback(&phdr_info, sizeof(phdr_info), param);
3868 lock_release(rtld_phdr_lock, &phdr_lockstate);
3873 fill_search_info(const char *dir, size_t dirlen, void *param)
3875 struct fill_search_info_args *arg;
3879 if (arg->request == RTLD_DI_SERINFOSIZE) {
3880 arg->serinfo->dls_cnt ++;
3881 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3883 struct dl_serpath *s_entry;
3885 s_entry = arg->serpath;
3886 s_entry->dls_name = arg->strspace;
3887 s_entry->dls_flags = arg->flags;
3889 strncpy(arg->strspace, dir, dirlen);
3890 arg->strspace[dirlen] = '\0';
3892 arg->strspace += dirlen + 1;
3900 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3902 struct dl_serinfo _info;
3903 struct fill_search_info_args args;
3905 args.request = RTLD_DI_SERINFOSIZE;
3906 args.serinfo = &_info;
3908 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3911 path_enumerate(obj->rpath, fill_search_info, NULL, &args);
3912 path_enumerate(ld_library_path, fill_search_info, NULL, &args);
3913 path_enumerate(obj->runpath, fill_search_info, NULL, &args);
3914 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args);
3915 if (!obj->z_nodeflib)
3916 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args);
3919 if (request == RTLD_DI_SERINFOSIZE) {
3920 info->dls_size = _info.dls_size;
3921 info->dls_cnt = _info.dls_cnt;
3925 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3926 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3930 args.request = RTLD_DI_SERINFO;
3931 args.serinfo = info;
3932 args.serpath = &info->dls_serpath[0];
3933 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3935 args.flags = LA_SER_RUNPATH;
3936 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL)
3939 args.flags = LA_SER_LIBPATH;
3940 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL)
3943 args.flags = LA_SER_RUNPATH;
3944 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL)
3947 args.flags = LA_SER_CONFIG;
3948 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args)
3952 args.flags = LA_SER_DEFAULT;
3953 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path,
3954 fill_search_info, NULL, &args) != NULL)
3960 rtld_dirname(const char *path, char *bname)
3964 /* Empty or NULL string gets treated as "." */
3965 if (path == NULL || *path == '\0') {
3971 /* Strip trailing slashes */
3972 endp = path + strlen(path) - 1;
3973 while (endp > path && *endp == '/')
3976 /* Find the start of the dir */
3977 while (endp > path && *endp != '/')
3980 /* Either the dir is "/" or there are no slashes */
3982 bname[0] = *endp == '/' ? '/' : '.';
3988 } while (endp > path && *endp == '/');
3991 if (endp - path + 2 > PATH_MAX)
3993 _rtld_error("Filename is too long: %s", path);
3997 strncpy(bname, path, endp - path + 1);
3998 bname[endp - path + 1] = '\0';
4003 rtld_dirname_abs(const char *path, char *base)
4007 if (realpath(path, base) == NULL) {
4008 _rtld_error("realpath \"%s\" failed (%s)", path,
4009 rtld_strerror(errno));
4012 dbg("%s -> %s", path, base);
4013 last = strrchr(base, '/');
4015 _rtld_error("non-abs result from realpath \"%s\"", path);
4024 linkmap_add(Obj_Entry *obj)
4026 struct link_map *l = &obj->linkmap;
4027 struct link_map *prev;
4029 obj->linkmap.l_name = obj->path;
4030 obj->linkmap.l_addr = obj->mapbase;
4031 obj->linkmap.l_ld = obj->dynamic;
4033 /* GDB needs load offset on MIPS to use the symbols */
4034 obj->linkmap.l_offs = obj->relocbase;
4037 if (r_debug.r_map == NULL) {
4043 * Scan to the end of the list, but not past the entry for the
4044 * dynamic linker, which we want to keep at the very end.
4046 for (prev = r_debug.r_map;
4047 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
4048 prev = prev->l_next)
4051 /* Link in the new entry. */
4053 l->l_next = prev->l_next;
4054 if (l->l_next != NULL)
4055 l->l_next->l_prev = l;
4060 linkmap_delete(Obj_Entry *obj)
4062 struct link_map *l = &obj->linkmap;
4064 if (l->l_prev == NULL) {
4065 if ((r_debug.r_map = l->l_next) != NULL)
4066 l->l_next->l_prev = NULL;
4070 if ((l->l_prev->l_next = l->l_next) != NULL)
4071 l->l_next->l_prev = l->l_prev;
4075 * Function for the debugger to set a breakpoint on to gain control.
4077 * The two parameters allow the debugger to easily find and determine
4078 * what the runtime loader is doing and to whom it is doing it.
4080 * When the loadhook trap is hit (r_debug_state, set at program
4081 * initialization), the arguments can be found on the stack:
4083 * +8 struct link_map *m
4084 * +4 struct r_debug *rd
4088 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused)
4091 * The following is a hack to force the compiler to emit calls to
4092 * this function, even when optimizing. If the function is empty,
4093 * the compiler is not obliged to emit any code for calls to it,
4094 * even when marked __noinline. However, gdb depends on those
4097 __compiler_membar();
4101 * A function called after init routines have completed. This can be used to
4102 * break before a program's entry routine is called, and can be used when
4103 * main is not available in the symbol table.
4106 _r_debug_postinit(struct link_map *m __unused)
4109 /* See r_debug_state(). */
4110 __compiler_membar();
4114 release_object(Obj_Entry *obj)
4117 if (obj->holdcount > 0) {
4118 obj->unholdfree = true;
4121 munmap(obj->mapbase, obj->mapsize);
4122 linkmap_delete(obj);
4127 * Get address of the pointer variable in the main program.
4128 * Prefer non-weak symbol over the weak one.
4130 static const void **
4131 get_program_var_addr(const char *name, RtldLockState *lockstate)
4136 symlook_init(&req, name);
4137 req.lockstate = lockstate;
4138 donelist_init(&donelist);
4139 if (symlook_global(&req, &donelist) != 0)
4141 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4142 return ((const void **)make_function_pointer(req.sym_out,
4144 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4145 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
4147 return ((const void **)(req.defobj_out->relocbase +
4148 req.sym_out->st_value));
4152 * Set a pointer variable in the main program to the given value. This
4153 * is used to set key variables such as "environ" before any of the
4154 * init functions are called.
4157 set_program_var(const char *name, const void *value)
4161 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4162 dbg("\"%s\": *%p <-- %p", name, addr, value);
4168 * Search the global objects, including dependencies and main object,
4169 * for the given symbol.
4172 symlook_global(SymLook *req, DoneList *donelist)
4175 const Objlist_Entry *elm;
4178 symlook_init_from_req(&req1, req);
4180 /* Search all objects loaded at program start up. */
4181 if (req->defobj_out == NULL ||
4182 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4183 res = symlook_list(&req1, &list_main, donelist);
4184 if (res == 0 && (req->defobj_out == NULL ||
4185 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4186 req->sym_out = req1.sym_out;
4187 req->defobj_out = req1.defobj_out;
4188 assert(req->defobj_out != NULL);
4192 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4193 STAILQ_FOREACH(elm, &list_global, link) {
4194 if (req->defobj_out != NULL &&
4195 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4197 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4198 if (res == 0 && (req->defobj_out == NULL ||
4199 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4200 req->sym_out = req1.sym_out;
4201 req->defobj_out = req1.defobj_out;
4202 assert(req->defobj_out != NULL);
4206 return (req->sym_out != NULL ? 0 : ESRCH);
4210 * Given a symbol name in a referencing object, find the corresponding
4211 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4212 * no definition was found. Returns a pointer to the Obj_Entry of the
4213 * defining object via the reference parameter DEFOBJ_OUT.
4216 symlook_default(SymLook *req, const Obj_Entry *refobj)
4219 const Objlist_Entry *elm;
4223 donelist_init(&donelist);
4224 symlook_init_from_req(&req1, req);
4227 * Look first in the referencing object if linked symbolically,
4228 * and similarly handle protected symbols.
4230 res = symlook_obj(&req1, refobj);
4231 if (res == 0 && (refobj->symbolic ||
4232 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) {
4233 req->sym_out = req1.sym_out;
4234 req->defobj_out = req1.defobj_out;
4235 assert(req->defobj_out != NULL);
4237 if (refobj->symbolic || req->defobj_out != NULL)
4238 donelist_check(&donelist, refobj);
4240 symlook_global(req, &donelist);
4242 /* Search all dlopened DAGs containing the referencing object. */
4243 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4244 if (req->sym_out != NULL &&
4245 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4247 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4248 if (res == 0 && (req->sym_out == NULL ||
4249 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4250 req->sym_out = req1.sym_out;
4251 req->defobj_out = req1.defobj_out;
4252 assert(req->defobj_out != NULL);
4257 * Search the dynamic linker itself, and possibly resolve the
4258 * symbol from there. This is how the application links to
4259 * dynamic linker services such as dlopen.
4261 if (req->sym_out == NULL ||
4262 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4263 res = symlook_obj(&req1, &obj_rtld);
4265 req->sym_out = req1.sym_out;
4266 req->defobj_out = req1.defobj_out;
4267 assert(req->defobj_out != NULL);
4271 return (req->sym_out != NULL ? 0 : ESRCH);
4275 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4278 const Obj_Entry *defobj;
4279 const Objlist_Entry *elm;
4285 STAILQ_FOREACH(elm, objlist, link) {
4286 if (donelist_check(dlp, elm->obj))
4288 symlook_init_from_req(&req1, req);
4289 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4290 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4292 defobj = req1.defobj_out;
4293 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4300 req->defobj_out = defobj;
4307 * Search the chain of DAGS cointed to by the given Needed_Entry
4308 * for a symbol of the given name. Each DAG is scanned completely
4309 * before advancing to the next one. Returns a pointer to the symbol,
4310 * or NULL if no definition was found.
4313 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4316 const Needed_Entry *n;
4317 const Obj_Entry *defobj;
4323 symlook_init_from_req(&req1, req);
4324 for (n = needed; n != NULL; n = n->next) {
4325 if (n->obj == NULL ||
4326 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
4328 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4330 defobj = req1.defobj_out;
4331 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4337 req->defobj_out = defobj;
4344 * Search the symbol table of a single shared object for a symbol of
4345 * the given name and version, if requested. Returns a pointer to the
4346 * symbol, or NULL if no definition was found. If the object is
4347 * filter, return filtered symbol from filtee.
4349 * The symbol's hash value is passed in for efficiency reasons; that
4350 * eliminates many recomputations of the hash value.
4353 symlook_obj(SymLook *req, const Obj_Entry *obj)
4357 int flags, res, mres;
4360 * If there is at least one valid hash at this point, we prefer to
4361 * use the faster GNU version if available.
4363 if (obj->valid_hash_gnu)
4364 mres = symlook_obj1_gnu(req, obj);
4365 else if (obj->valid_hash_sysv)
4366 mres = symlook_obj1_sysv(req, obj);
4371 if (obj->needed_filtees != NULL) {
4372 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4373 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4374 donelist_init(&donelist);
4375 symlook_init_from_req(&req1, req);
4376 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
4378 req->sym_out = req1.sym_out;
4379 req->defobj_out = req1.defobj_out;
4383 if (obj->needed_aux_filtees != NULL) {
4384 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4385 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4386 donelist_init(&donelist);
4387 symlook_init_from_req(&req1, req);
4388 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
4390 req->sym_out = req1.sym_out;
4391 req->defobj_out = req1.defobj_out;
4399 /* Symbol match routine common to both hash functions */
4401 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4402 const unsigned long symnum)
4405 const Elf_Sym *symp;
4408 symp = obj->symtab + symnum;
4409 strp = obj->strtab + symp->st_name;
4411 switch (ELF_ST_TYPE(symp->st_info)) {
4417 if (symp->st_value == 0)
4421 if (symp->st_shndx != SHN_UNDEF)
4424 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4425 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4432 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4435 if (req->ventry == NULL) {
4436 if (obj->versyms != NULL) {
4437 verndx = VER_NDX(obj->versyms[symnum]);
4438 if (verndx > obj->vernum) {
4440 "%s: symbol %s references wrong version %d",
4441 obj->path, obj->strtab + symnum, verndx);
4445 * If we are not called from dlsym (i.e. this
4446 * is a normal relocation from unversioned
4447 * binary), accept the symbol immediately if
4448 * it happens to have first version after this
4449 * shared object became versioned. Otherwise,
4450 * if symbol is versioned and not hidden,
4451 * remember it. If it is the only symbol with
4452 * this name exported by the shared object, it
4453 * will be returned as a match by the calling
4454 * function. If symbol is global (verndx < 2)
4455 * accept it unconditionally.
4457 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4458 verndx == VER_NDX_GIVEN) {
4459 result->sym_out = symp;
4462 else if (verndx >= VER_NDX_GIVEN) {
4463 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4465 if (result->vsymp == NULL)
4466 result->vsymp = symp;
4472 result->sym_out = symp;
4475 if (obj->versyms == NULL) {
4476 if (object_match_name(obj, req->ventry->name)) {
4477 _rtld_error("%s: object %s should provide version %s "
4478 "for symbol %s", obj_rtld.path, obj->path,
4479 req->ventry->name, obj->strtab + symnum);
4483 verndx = VER_NDX(obj->versyms[symnum]);
4484 if (verndx > obj->vernum) {
4485 _rtld_error("%s: symbol %s references wrong version %d",
4486 obj->path, obj->strtab + symnum, verndx);
4489 if (obj->vertab[verndx].hash != req->ventry->hash ||
4490 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4492 * Version does not match. Look if this is a
4493 * global symbol and if it is not hidden. If
4494 * global symbol (verndx < 2) is available,
4495 * use it. Do not return symbol if we are
4496 * called by dlvsym, because dlvsym looks for
4497 * a specific version and default one is not
4498 * what dlvsym wants.
4500 if ((req->flags & SYMLOOK_DLSYM) ||
4501 (verndx >= VER_NDX_GIVEN) ||
4502 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4506 result->sym_out = symp;
4511 * Search for symbol using SysV hash function.
4512 * obj->buckets is known not to be NULL at this point; the test for this was
4513 * performed with the obj->valid_hash_sysv assignment.
4516 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4518 unsigned long symnum;
4519 Sym_Match_Result matchres;
4521 matchres.sym_out = NULL;
4522 matchres.vsymp = NULL;
4523 matchres.vcount = 0;
4525 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4526 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4527 if (symnum >= obj->nchains)
4528 return (ESRCH); /* Bad object */
4530 if (matched_symbol(req, obj, &matchres, symnum)) {
4531 req->sym_out = matchres.sym_out;
4532 req->defobj_out = obj;
4536 if (matchres.vcount == 1) {
4537 req->sym_out = matchres.vsymp;
4538 req->defobj_out = obj;
4544 /* Search for symbol using GNU hash function */
4546 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4548 Elf_Addr bloom_word;
4549 const Elf32_Word *hashval;
4551 Sym_Match_Result matchres;
4552 unsigned int h1, h2;
4553 unsigned long symnum;
4555 matchres.sym_out = NULL;
4556 matchres.vsymp = NULL;
4557 matchres.vcount = 0;
4559 /* Pick right bitmask word from Bloom filter array */
4560 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4561 obj->maskwords_bm_gnu];
4563 /* Calculate modulus word size of gnu hash and its derivative */
4564 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4565 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4567 /* Filter out the "definitely not in set" queries */
4568 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4571 /* Locate hash chain and corresponding value element*/
4572 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4575 hashval = &obj->chain_zero_gnu[bucket];
4577 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4578 symnum = hashval - obj->chain_zero_gnu;
4579 if (matched_symbol(req, obj, &matchres, symnum)) {
4580 req->sym_out = matchres.sym_out;
4581 req->defobj_out = obj;
4585 } while ((*hashval++ & 1) == 0);
4586 if (matchres.vcount == 1) {
4587 req->sym_out = matchres.vsymp;
4588 req->defobj_out = obj;
4595 trace_loaded_objects(Obj_Entry *obj)
4597 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4600 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL)
4603 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL)
4604 fmt1 = "\t%o => %p (%x)\n";
4606 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL)
4607 fmt2 = "\t%o (%x)\n";
4609 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL"));
4611 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4612 Needed_Entry *needed;
4613 const char *name, *path;
4618 if (list_containers && obj->needed != NULL)
4619 rtld_printf("%s:\n", obj->path);
4620 for (needed = obj->needed; needed; needed = needed->next) {
4621 if (needed->obj != NULL) {
4622 if (needed->obj->traced && !list_containers)
4624 needed->obj->traced = true;
4625 path = needed->obj->path;
4629 name = obj->strtab + needed->name;
4630 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4632 fmt = is_lib ? fmt1 : fmt2;
4633 while ((c = *fmt++) != '\0') {
4659 rtld_putstr(main_local);
4662 rtld_putstr(obj_main->path);
4669 rtld_printf("%d", sodp->sod_major);
4672 rtld_printf("%d", sodp->sod_minor);
4679 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4692 * Unload a dlopened object and its dependencies from memory and from
4693 * our data structures. It is assumed that the DAG rooted in the
4694 * object has already been unreferenced, and that the object has a
4695 * reference count of 0.
4698 unload_object(Obj_Entry *root, RtldLockState *lockstate)
4700 Obj_Entry marker, *obj, *next;
4702 assert(root->refcount == 0);
4705 * Pass over the DAG removing unreferenced objects from
4706 * appropriate lists.
4708 unlink_object(root);
4710 /* Unmap all objects that are no longer referenced. */
4711 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
4712 next = TAILQ_NEXT(obj, next);
4713 if (obj->marker || obj->refcount != 0)
4715 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
4716 obj->mapsize, 0, obj->path);
4717 dbg("unloading \"%s\"", obj->path);
4719 * Unlink the object now to prevent new references from
4720 * being acquired while the bind lock is dropped in
4721 * recursive dlclose() invocations.
4723 TAILQ_REMOVE(&obj_list, obj, next);
4726 if (obj->filtees_loaded) {
4728 init_marker(&marker);
4729 TAILQ_INSERT_BEFORE(next, &marker, next);
4730 unload_filtees(obj, lockstate);
4731 next = TAILQ_NEXT(&marker, next);
4732 TAILQ_REMOVE(&obj_list, &marker, next);
4734 unload_filtees(obj, lockstate);
4736 release_object(obj);
4741 unlink_object(Obj_Entry *root)
4745 if (root->refcount == 0) {
4746 /* Remove the object from the RTLD_GLOBAL list. */
4747 objlist_remove(&list_global, root);
4749 /* Remove the object from all objects' DAG lists. */
4750 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4751 objlist_remove(&elm->obj->dldags, root);
4752 if (elm->obj != root)
4753 unlink_object(elm->obj);
4759 ref_dag(Obj_Entry *root)
4763 assert(root->dag_inited);
4764 STAILQ_FOREACH(elm, &root->dagmembers, link)
4765 elm->obj->refcount++;
4769 unref_dag(Obj_Entry *root)
4773 assert(root->dag_inited);
4774 STAILQ_FOREACH(elm, &root->dagmembers, link)
4775 elm->obj->refcount--;
4779 * Common code for MD __tls_get_addr().
4781 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4783 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4785 Elf_Addr *newdtv, *dtv;
4786 RtldLockState lockstate;
4790 /* Check dtv generation in case new modules have arrived */
4791 if (dtv[0] != tls_dtv_generation) {
4792 wlock_acquire(rtld_bind_lock, &lockstate);
4793 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4795 if (to_copy > tls_max_index)
4796 to_copy = tls_max_index;
4797 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4798 newdtv[0] = tls_dtv_generation;
4799 newdtv[1] = tls_max_index;
4801 lock_release(rtld_bind_lock, &lockstate);
4802 dtv = *dtvp = newdtv;
4805 /* Dynamically allocate module TLS if necessary */
4806 if (dtv[index + 1] == 0) {
4807 /* Signal safe, wlock will block out signals. */
4808 wlock_acquire(rtld_bind_lock, &lockstate);
4809 if (!dtv[index + 1])
4810 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4811 lock_release(rtld_bind_lock, &lockstate);
4813 return ((void *)(dtv[index + 1] + offset));
4817 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4822 /* Check dtv generation in case new modules have arrived */
4823 if (__predict_true(dtv[0] == tls_dtv_generation &&
4824 dtv[index + 1] != 0))
4825 return ((void *)(dtv[index + 1] + offset));
4826 return (tls_get_addr_slow(dtvp, index, offset));
4829 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
4830 defined(__powerpc__) || defined(__riscv)
4833 * Return pointer to allocated TLS block
4836 get_tls_block_ptr(void *tcb, size_t tcbsize)
4838 size_t extra_size, post_size, pre_size, tls_block_size;
4839 size_t tls_init_align;
4841 tls_init_align = MAX(obj_main->tlsalign, 1);
4843 /* Compute fragments sizes. */
4844 extra_size = tcbsize - TLS_TCB_SIZE;
4845 post_size = calculate_tls_post_size(tls_init_align);
4846 tls_block_size = tcbsize + post_size;
4847 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4849 return ((char *)tcb - pre_size - extra_size);
4853 * Allocate Static TLS using the Variant I method.
4855 * For details on the layout, see lib/libc/gen/tls.c.
4857 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as
4858 * it is based on tls_last_offset, and TLS offsets here are really TCB
4859 * offsets, whereas libc's tls_static_space is just the executable's static
4863 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4867 Elf_Addr *dtv, **tcb;
4870 size_t extra_size, maxalign, post_size, pre_size, tls_block_size;
4871 size_t tls_init_align;
4873 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4876 assert(tcbsize >= TLS_TCB_SIZE);
4877 maxalign = MAX(tcbalign, tls_static_max_align);
4878 tls_init_align = MAX(obj_main->tlsalign, 1);
4880 /* Compute fragmets sizes. */
4881 extra_size = tcbsize - TLS_TCB_SIZE;
4882 post_size = calculate_tls_post_size(tls_init_align);
4883 tls_block_size = tcbsize + post_size;
4884 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4885 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size;
4887 /* Allocate whole TLS block */
4888 tls_block = malloc_aligned(tls_block_size, maxalign);
4889 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size);
4891 if (oldtcb != NULL) {
4892 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize),
4894 free_aligned(get_tls_block_ptr(oldtcb, tcbsize));
4896 /* Adjust the DTV. */
4898 for (i = 0; i < dtv[1]; i++) {
4899 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4900 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4901 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb;
4905 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4907 dtv[0] = tls_dtv_generation;
4908 dtv[1] = tls_max_index;
4910 for (obj = globallist_curr(objs); obj != NULL;
4911 obj = globallist_next(obj)) {
4912 if (obj->tlsoffset > 0) {
4913 addr = (Elf_Addr)tcb + obj->tlsoffset;
4914 if (obj->tlsinitsize > 0)
4915 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4916 if (obj->tlssize > obj->tlsinitsize)
4917 memset((void*)(addr + obj->tlsinitsize), 0,
4918 obj->tlssize - obj->tlsinitsize);
4919 dtv[obj->tlsindex + 1] = addr;
4928 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
4931 Elf_Addr tlsstart, tlsend;
4933 size_t dtvsize, i, tls_init_align;
4935 assert(tcbsize >= TLS_TCB_SIZE);
4936 tls_init_align = MAX(obj_main->tlsalign, 1);
4938 /* Compute fragments sizes. */
4939 post_size = calculate_tls_post_size(tls_init_align);
4941 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size;
4942 tlsend = (Elf_Addr)tcb + tls_static_space;
4944 dtv = *(Elf_Addr **)tcb;
4946 for (i = 0; i < dtvsize; i++) {
4947 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4948 free((void*)dtv[i+2]);
4952 free_aligned(get_tls_block_ptr(tcb, tcbsize));
4957 #if defined(__i386__) || defined(__amd64__)
4960 * Allocate Static TLS using the Variant II method.
4963 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4966 size_t size, ralign;
4968 Elf_Addr *dtv, *olddtv;
4969 Elf_Addr segbase, oldsegbase, addr;
4973 if (tls_static_max_align > ralign)
4974 ralign = tls_static_max_align;
4975 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4977 assert(tcbsize >= 2*sizeof(Elf_Addr));
4978 tls = malloc_aligned(size, ralign);
4979 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4981 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4982 ((Elf_Addr*)segbase)[0] = segbase;
4983 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4985 dtv[0] = tls_dtv_generation;
4986 dtv[1] = tls_max_index;
4990 * Copy the static TLS block over whole.
4992 oldsegbase = (Elf_Addr) oldtls;
4993 memcpy((void *)(segbase - tls_static_space),
4994 (const void *)(oldsegbase - tls_static_space),
4998 * If any dynamic TLS blocks have been created tls_get_addr(),
5001 olddtv = ((Elf_Addr**)oldsegbase)[1];
5002 for (i = 0; i < olddtv[1]; i++) {
5003 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
5004 dtv[i+2] = olddtv[i+2];
5010 * We assume that this block was the one we created with
5011 * allocate_initial_tls().
5013 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
5015 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
5016 if (obj->marker || obj->tlsoffset == 0)
5018 addr = segbase - obj->tlsoffset;
5019 memset((void*)(addr + obj->tlsinitsize),
5020 0, obj->tlssize - obj->tlsinitsize);
5022 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
5023 obj->static_tls_copied = true;
5025 dtv[obj->tlsindex + 1] = addr;
5029 return (void*) segbase;
5033 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign)
5036 size_t size, ralign;
5038 Elf_Addr tlsstart, tlsend;
5041 * Figure out the size of the initial TLS block so that we can
5042 * find stuff which ___tls_get_addr() allocated dynamically.
5045 if (tls_static_max_align > ralign)
5046 ralign = tls_static_max_align;
5047 size = round(tls_static_space, ralign);
5049 dtv = ((Elf_Addr**)tls)[1];
5051 tlsend = (Elf_Addr) tls;
5052 tlsstart = tlsend - size;
5053 for (i = 0; i < dtvsize; i++) {
5054 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
5055 free_aligned((void *)dtv[i + 2]);
5059 free_aligned((void *)tlsstart);
5066 * Allocate TLS block for module with given index.
5069 allocate_module_tls(int index)
5074 TAILQ_FOREACH(obj, &obj_list, next) {
5077 if (obj->tlsindex == index)
5081 _rtld_error("Can't find module with TLS index %d", index);
5085 p = malloc_aligned(obj->tlssize, obj->tlsalign);
5086 memcpy(p, obj->tlsinit, obj->tlsinitsize);
5087 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
5093 allocate_tls_offset(Obj_Entry *obj)
5100 if (obj->tlssize == 0) {
5101 obj->tls_done = true;
5105 if (tls_last_offset == 0)
5106 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
5108 off = calculate_tls_offset(tls_last_offset, tls_last_size,
5109 obj->tlssize, obj->tlsalign);
5112 * If we have already fixed the size of the static TLS block, we
5113 * must stay within that size. When allocating the static TLS, we
5114 * leave a small amount of space spare to be used for dynamically
5115 * loading modules which use static TLS.
5117 if (tls_static_space != 0) {
5118 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
5120 } else if (obj->tlsalign > tls_static_max_align) {
5121 tls_static_max_align = obj->tlsalign;
5124 tls_last_offset = obj->tlsoffset = off;
5125 tls_last_size = obj->tlssize;
5126 obj->tls_done = true;
5132 free_tls_offset(Obj_Entry *obj)
5136 * If we were the last thing to allocate out of the static TLS
5137 * block, we give our space back to the 'allocator'. This is a
5138 * simplistic workaround to allow libGL.so.1 to be loaded and
5139 * unloaded multiple times.
5141 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
5142 == calculate_tls_end(tls_last_offset, tls_last_size)) {
5143 tls_last_offset -= obj->tlssize;
5149 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
5152 RtldLockState lockstate;
5154 wlock_acquire(rtld_bind_lock, &lockstate);
5155 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
5157 lock_release(rtld_bind_lock, &lockstate);
5162 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
5164 RtldLockState lockstate;
5166 wlock_acquire(rtld_bind_lock, &lockstate);
5167 free_tls(tcb, tcbsize, tcbalign);
5168 lock_release(rtld_bind_lock, &lockstate);
5172 object_add_name(Obj_Entry *obj, const char *name)
5178 entry = malloc(sizeof(Name_Entry) + len);
5180 if (entry != NULL) {
5181 strcpy(entry->name, name);
5182 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5187 object_match_name(const Obj_Entry *obj, const char *name)
5191 STAILQ_FOREACH(entry, &obj->names, link) {
5192 if (strcmp(name, entry->name) == 0)
5199 locate_dependency(const Obj_Entry *obj, const char *name)
5201 const Objlist_Entry *entry;
5202 const Needed_Entry *needed;
5204 STAILQ_FOREACH(entry, &list_main, link) {
5205 if (object_match_name(entry->obj, name))
5209 for (needed = obj->needed; needed != NULL; needed = needed->next) {
5210 if (strcmp(obj->strtab + needed->name, name) == 0 ||
5211 (needed->obj != NULL && object_match_name(needed->obj, name))) {
5213 * If there is DT_NEEDED for the name we are looking for,
5214 * we are all set. Note that object might not be found if
5215 * dependency was not loaded yet, so the function can
5216 * return NULL here. This is expected and handled
5217 * properly by the caller.
5219 return (needed->obj);
5222 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
5228 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
5229 const Elf_Vernaux *vna)
5231 const Elf_Verdef *vd;
5232 const char *vername;
5234 vername = refobj->strtab + vna->vna_name;
5235 vd = depobj->verdef;
5237 _rtld_error("%s: version %s required by %s not defined",
5238 depobj->path, vername, refobj->path);
5242 if (vd->vd_version != VER_DEF_CURRENT) {
5243 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5244 depobj->path, vd->vd_version);
5247 if (vna->vna_hash == vd->vd_hash) {
5248 const Elf_Verdaux *aux = (const Elf_Verdaux *)
5249 ((const char *)vd + vd->vd_aux);
5250 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
5253 if (vd->vd_next == 0)
5255 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5257 if (vna->vna_flags & VER_FLG_WEAK)
5259 _rtld_error("%s: version %s required by %s not found",
5260 depobj->path, vername, refobj->path);
5265 rtld_verify_object_versions(Obj_Entry *obj)
5267 const Elf_Verneed *vn;
5268 const Elf_Verdef *vd;
5269 const Elf_Verdaux *vda;
5270 const Elf_Vernaux *vna;
5271 const Obj_Entry *depobj;
5272 int maxvernum, vernum;
5274 if (obj->ver_checked)
5276 obj->ver_checked = true;
5280 * Walk over defined and required version records and figure out
5281 * max index used by any of them. Do very basic sanity checking
5285 while (vn != NULL) {
5286 if (vn->vn_version != VER_NEED_CURRENT) {
5287 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
5288 obj->path, vn->vn_version);
5291 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5293 vernum = VER_NEED_IDX(vna->vna_other);
5294 if (vernum > maxvernum)
5296 if (vna->vna_next == 0)
5298 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5300 if (vn->vn_next == 0)
5302 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5306 while (vd != NULL) {
5307 if (vd->vd_version != VER_DEF_CURRENT) {
5308 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5309 obj->path, vd->vd_version);
5312 vernum = VER_DEF_IDX(vd->vd_ndx);
5313 if (vernum > maxvernum)
5315 if (vd->vd_next == 0)
5317 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5324 * Store version information in array indexable by version index.
5325 * Verify that object version requirements are satisfied along the
5328 obj->vernum = maxvernum + 1;
5329 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
5332 while (vd != NULL) {
5333 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
5334 vernum = VER_DEF_IDX(vd->vd_ndx);
5335 assert(vernum <= maxvernum);
5336 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux);
5337 obj->vertab[vernum].hash = vd->vd_hash;
5338 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
5339 obj->vertab[vernum].file = NULL;
5340 obj->vertab[vernum].flags = 0;
5342 if (vd->vd_next == 0)
5344 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5348 while (vn != NULL) {
5349 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
5352 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5354 if (check_object_provided_version(obj, depobj, vna))
5356 vernum = VER_NEED_IDX(vna->vna_other);
5357 assert(vernum <= maxvernum);
5358 obj->vertab[vernum].hash = vna->vna_hash;
5359 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
5360 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
5361 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
5362 VER_INFO_HIDDEN : 0;
5363 if (vna->vna_next == 0)
5365 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5367 if (vn->vn_next == 0)
5369 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5375 rtld_verify_versions(const Objlist *objlist)
5377 Objlist_Entry *entry;
5381 STAILQ_FOREACH(entry, objlist, link) {
5383 * Skip dummy objects or objects that have their version requirements
5386 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
5388 if (rtld_verify_object_versions(entry->obj) == -1) {
5390 if (ld_tracing == NULL)
5394 if (rc == 0 || ld_tracing != NULL)
5395 rc = rtld_verify_object_versions(&obj_rtld);
5400 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
5405 vernum = VER_NDX(obj->versyms[symnum]);
5406 if (vernum >= obj->vernum) {
5407 _rtld_error("%s: symbol %s has wrong verneed value %d",
5408 obj->path, obj->strtab + symnum, vernum);
5409 } else if (obj->vertab[vernum].hash != 0) {
5410 return &obj->vertab[vernum];
5417 _rtld_get_stack_prot(void)
5420 return (stack_prot);
5424 _rtld_is_dlopened(void *arg)
5427 RtldLockState lockstate;
5430 rlock_acquire(rtld_bind_lock, &lockstate);
5433 obj = obj_from_addr(arg);
5435 _rtld_error("No shared object contains address");
5436 lock_release(rtld_bind_lock, &lockstate);
5439 res = obj->dlopened ? 1 : 0;
5440 lock_release(rtld_bind_lock, &lockstate);
5445 obj_remap_relro(Obj_Entry *obj, int prot)
5448 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size,
5450 _rtld_error("%s: Cannot set relro protection to %#x: %s",
5451 obj->path, prot, rtld_strerror(errno));
5458 obj_disable_relro(Obj_Entry *obj)
5461 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE));
5465 obj_enforce_relro(Obj_Entry *obj)
5468 return (obj_remap_relro(obj, PROT_READ));
5472 map_stacks_exec(RtldLockState *lockstate)
5474 void (*thr_map_stacks_exec)(void);
5476 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
5478 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
5479 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
5480 if (thr_map_stacks_exec != NULL) {
5481 stack_prot |= PROT_EXEC;
5482 thr_map_stacks_exec();
5487 distribute_static_tls(Objlist *list, RtldLockState *lockstate)
5491 void (*distrib)(size_t, void *, size_t, size_t);
5493 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t)
5494 get_program_var_addr("__pthread_distribute_static_tls", lockstate);
5495 if (distrib == NULL)
5497 STAILQ_FOREACH(elm, list, link) {
5499 if (obj->marker || !obj->tls_done || obj->static_tls_copied)
5501 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize,
5503 obj->static_tls_copied = true;
5508 symlook_init(SymLook *dst, const char *name)
5511 bzero(dst, sizeof(*dst));
5513 dst->hash = elf_hash(name);
5514 dst->hash_gnu = gnu_hash(name);
5518 symlook_init_from_req(SymLook *dst, const SymLook *src)
5521 dst->name = src->name;
5522 dst->hash = src->hash;
5523 dst->hash_gnu = src->hash_gnu;
5524 dst->ventry = src->ventry;
5525 dst->flags = src->flags;
5526 dst->defobj_out = NULL;
5527 dst->sym_out = NULL;
5528 dst->lockstate = src->lockstate;
5532 open_binary_fd(const char *argv0, bool search_in_path,
5533 const char **binpath_res)
5535 char *binpath, *pathenv, *pe, *res1;
5541 if (search_in_path && strchr(argv0, '/') == NULL) {
5542 binpath = xmalloc(PATH_MAX);
5543 pathenv = getenv("PATH");
5544 if (pathenv == NULL) {
5545 _rtld_error("-p and no PATH environment variable");
5548 pathenv = strdup(pathenv);
5549 if (pathenv == NULL) {
5550 _rtld_error("Cannot allocate memory");
5555 while ((pe = strsep(&pathenv, ":")) != NULL) {
5556 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX)
5558 if (binpath[0] != '\0' &&
5559 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX)
5561 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX)
5563 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
5564 if (fd != -1 || errno != ENOENT) {
5571 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
5576 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno));
5579 if (res != NULL && res[0] != '/') {
5580 res1 = xmalloc(PATH_MAX);
5581 if (realpath(res, res1) != NULL) {
5583 free(__DECONST(char *, res));
5594 * Parse a set of command-line arguments.
5597 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp)
5600 int fd, i, j, arglen;
5603 dbg("Parsing command-line arguments");
5607 for (i = 1; i < argc; i++ ) {
5609 dbg("argv[%d]: '%s'", i, arg);
5612 * rtld arguments end with an explicit "--" or with the first
5613 * non-prefixed argument.
5615 if (strcmp(arg, "--") == 0) {
5623 * All other arguments are single-character options that can
5624 * be combined, so we need to search through `arg` for them.
5626 arglen = strlen(arg);
5627 for (j = 1; j < arglen; j++) {
5630 print_usage(argv[0]);
5632 } else if (opt == 'f') {
5634 * -f XX can be used to specify a
5635 * descriptor for the binary named at
5636 * the command line (i.e., the later
5637 * argument will specify the process
5638 * name but the descriptor is what
5639 * will actually be executed).
5641 * -f must be the last option in, e.g., -abcf.
5643 if (j != arglen - 1) {
5644 _rtld_error("Invalid options: %s", arg);
5648 fd = parse_integer(argv[i]);
5651 "Invalid file descriptor: '%s'",
5657 } else if (opt == 'p') {
5660 _rtld_error("Invalid argument: '%s'", arg);
5661 print_usage(argv[0]);
5671 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
5674 parse_integer(const char *str)
5676 static const int RADIX = 10; /* XXXJA: possibly support hex? */
5683 for (c = *str; c != '\0'; c = *++str) {
5684 if (c < '0' || c > '9')
5691 /* Make sure we actually parsed something. */
5698 print_usage(const char *argv0)
5701 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n"
5704 " -h Display this help message\n"
5705 " -p Search in PATH for named binary\n"
5706 " -f <FD> Execute <FD> instead of searching for <binary>\n"
5707 " -- End of RTLD options\n"
5708 " <binary> Name of process to execute\n"
5709 " <args> Arguments to the executed process\n", argv0);
5713 * Overrides for libc_pic-provided functions.
5717 __getosreldate(void)
5727 oid[1] = KERN_OSRELDATE;
5729 len = sizeof(osrel);
5730 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5731 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5736 rtld_strerror(int errnum)
5739 if (errnum < 0 || errnum >= sys_nerr)
5740 return ("Unknown error");
5741 return (sys_errlist[errnum]);
5746 malloc(size_t nbytes)
5749 return (__crt_malloc(nbytes));
5753 calloc(size_t num, size_t size)
5756 return (__crt_calloc(num, size));
5767 realloc(void *cp, size_t nbytes)
5770 return (__crt_realloc(cp, nbytes));