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,
141 static int parse_integer(const char *);
142 static void *path_enumerate(const char *, path_enum_proc, const char *, void *);
143 static void print_usage(const char *argv0);
144 static void release_object(Obj_Entry *);
145 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
146 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
147 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
148 int flags, RtldLockState *lockstate);
149 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
151 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *);
152 static int rtld_dirname(const char *, char *);
153 static int rtld_dirname_abs(const char *, char *);
154 static void *rtld_dlopen(const char *name, int fd, int mode);
155 static void rtld_exit(void);
156 static void rtld_nop_exit(void);
157 static char *search_library_path(const char *, const char *, const char *,
159 static char *search_library_pathfds(const char *, const char *, int *);
160 static const void **get_program_var_addr(const char *, RtldLockState *);
161 static void set_program_var(const char *, const void *);
162 static int symlook_default(SymLook *, const Obj_Entry *refobj);
163 static int symlook_global(SymLook *, DoneList *);
164 static void symlook_init_from_req(SymLook *, const SymLook *);
165 static int symlook_list(SymLook *, const Objlist *, DoneList *);
166 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
167 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
168 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
169 static void trace_loaded_objects(Obj_Entry *);
170 static void unlink_object(Obj_Entry *);
171 static void unload_object(Obj_Entry *, RtldLockState *lockstate);
172 static void unref_dag(Obj_Entry *);
173 static void ref_dag(Obj_Entry *);
174 static char *origin_subst_one(Obj_Entry *, char *, const char *,
176 static char *origin_subst(Obj_Entry *, const char *);
177 static bool obj_resolve_origin(Obj_Entry *obj);
178 static void preinit_main(void);
179 static int rtld_verify_versions(const Objlist *);
180 static int rtld_verify_object_versions(Obj_Entry *);
181 static void object_add_name(Obj_Entry *, const char *);
182 static int object_match_name(const Obj_Entry *, const char *);
183 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
184 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
185 struct dl_phdr_info *phdr_info);
186 static uint32_t gnu_hash(const char *);
187 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
188 const unsigned long);
190 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
191 void _r_debug_postinit(struct link_map *) __noinline __exported;
193 int __sys_openat(int, const char *, int, ...);
198 static char *error_message; /* Message for dlerror(), or NULL */
199 struct r_debug r_debug __exported; /* for GDB; */
200 static bool libmap_disable; /* Disable libmap */
201 static bool ld_loadfltr; /* Immediate filters processing */
202 static char *libmap_override; /* Maps to use in addition to libmap.conf */
203 static bool trust; /* False for setuid and setgid programs */
204 static bool dangerous_ld_env; /* True if environment variables have been
205 used to affect the libraries loaded */
206 bool ld_bind_not; /* Disable PLT update */
207 static char *ld_bind_now; /* Environment variable for immediate binding */
208 static char *ld_debug; /* Environment variable for debugging */
209 static char *ld_library_path; /* Environment variable for search path */
210 static char *ld_library_dirs; /* Environment variable for library descriptors */
211 static char *ld_preload; /* Environment variable for libraries to
213 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */
214 static const char *ld_tracing; /* Called from ldd to print libs */
215 static char *ld_utrace; /* Use utrace() to log events. */
216 static struct obj_entry_q obj_list; /* Queue of all loaded objects */
217 static Obj_Entry *obj_main; /* The main program shared object */
218 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
219 static unsigned int obj_count; /* Number of objects in obj_list */
220 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
222 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
223 STAILQ_HEAD_INITIALIZER(list_global);
224 static Objlist list_main = /* Objects loaded at program startup */
225 STAILQ_HEAD_INITIALIZER(list_main);
226 static Objlist list_fini = /* Objects needing fini() calls */
227 STAILQ_HEAD_INITIALIZER(list_fini);
229 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
231 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
233 extern Elf_Dyn _DYNAMIC;
234 #pragma weak _DYNAMIC
236 int dlclose(void *) __exported;
237 char *dlerror(void) __exported;
238 void *dlopen(const char *, int) __exported;
239 void *fdlopen(int, int) __exported;
240 void *dlsym(void *, const char *) __exported;
241 dlfunc_t dlfunc(void *, const char *) __exported;
242 void *dlvsym(void *, const char *, const char *) __exported;
243 int dladdr(const void *, Dl_info *) __exported;
244 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
245 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
246 int dlinfo(void *, int , void *) __exported;
247 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
248 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
249 int _rtld_get_stack_prot(void) __exported;
250 int _rtld_is_dlopened(void *) __exported;
251 void _rtld_error(const char *, ...) __exported;
253 /* Only here to fix -Wmissing-prototypes warnings */
254 int __getosreldate(void);
255 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp);
256 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff);
260 static int osreldate;
263 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
264 static int max_stack_flags;
267 * Global declarations normally provided by crt1. The dynamic linker is
268 * not built with crt1, so we have to provide them ourselves.
274 * Used to pass argc, argv to init functions.
280 * Globals to control TLS allocation.
282 size_t tls_last_offset; /* Static TLS offset of last module */
283 size_t tls_last_size; /* Static TLS size of last module */
284 size_t tls_static_space; /* Static TLS space allocated */
285 static size_t tls_static_max_align;
286 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */
287 int tls_max_index = 1; /* Largest module index allocated */
289 static bool ld_library_path_rpath = false;
290 bool ld_fast_sigblock = false;
293 * Globals for path names, and such
295 const char *ld_elf_hints_default = _PATH_ELF_HINTS;
296 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
297 const char *ld_path_rtld = _PATH_RTLD;
298 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
299 const char *ld_env_prefix = LD_;
301 static void (*rtld_exit_ptr)(void);
304 * Fill in a DoneList with an allocation large enough to hold all of
305 * the currently-loaded objects. Keep this as a macro since it calls
306 * alloca and we want that to occur within the scope of the caller.
308 #define donelist_init(dlp) \
309 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
310 assert((dlp)->objs != NULL), \
311 (dlp)->num_alloc = obj_count, \
314 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
315 if (ld_utrace != NULL) \
316 ld_utrace_log(e, h, mb, ms, r, n); \
320 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
321 int refcnt, const char *name)
323 struct utrace_rtld ut;
324 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG;
326 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig));
329 ut.mapbase = mapbase;
330 ut.mapsize = mapsize;
332 bzero(ut.name, sizeof(ut.name));
334 strlcpy(ut.name, name, sizeof(ut.name));
335 utrace(&ut, sizeof(ut));
338 #ifdef RTLD_VARIANT_ENV_NAMES
340 * construct the env variable based on the type of binary that's
343 static inline const char *
346 static char buffer[128];
348 strlcpy(buffer, ld_env_prefix, sizeof(buffer));
349 strlcat(buffer, var, sizeof(buffer));
357 * Main entry point for dynamic linking. The first argument is the
358 * stack pointer. The stack is expected to be laid out as described
359 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
360 * Specifically, the stack pointer points to a word containing
361 * ARGC. Following that in the stack is a null-terminated sequence
362 * of pointers to argument strings. Then comes a null-terminated
363 * sequence of pointers to environment strings. Finally, there is a
364 * sequence of "auxiliary vector" entries.
366 * The second argument points to a place to store the dynamic linker's
367 * exit procedure pointer and the third to a place to store the main
370 * The return value is the main program's entry point.
373 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
375 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT];
376 Objlist_Entry *entry;
377 Obj_Entry *last_interposer, *obj, *preload_tail;
378 const Elf_Phdr *phdr;
380 RtldLockState lockstate;
383 char **argv, **env, **envp, *kexecpath, *library_path_rpath;
384 const char *argv0, *binpath;
386 char buf[MAXPATHLEN];
387 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc;
390 int old_auxv_format = 1;
392 bool dir_enable, direct_exec, explicit_fd, search_in_path;
395 * On entry, the dynamic linker itself has not been relocated yet.
396 * Be very careful not to reference any global data until after
397 * init_rtld has returned. It is OK to reference file-scope statics
398 * and string constants, and to call static and global functions.
401 /* Find the auxiliary vector on the stack. */
405 sp += argc + 1; /* Skip over arguments and NULL terminator */
407 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
409 aux = (Elf_Auxinfo *) sp;
411 /* Digest the auxiliary vector. */
412 for (i = 0; i < AT_COUNT; i++)
414 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
415 if (auxp->a_type < AT_COUNT)
416 aux_info[auxp->a_type] = auxp;
418 if (auxp->a_type == 23) /* AT_STACKPROT */
424 if (old_auxv_format) {
425 /* Remap from old-style auxv numbers. */
426 aux_info[23] = aux_info[21]; /* AT_STACKPROT */
427 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */
428 aux_info[19] = aux_info[17]; /* AT_NCPUS */
429 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */
430 aux_info[15] = aux_info[13]; /* AT_EXECPATH */
431 aux_info[13] = NULL; /* AT_GID */
433 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */
434 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */
435 aux_info[16] = aux_info[14]; /* AT_CANARY */
436 aux_info[14] = NULL; /* AT_EGID */
440 /* Initialize and relocate ourselves. */
441 assert(aux_info[AT_BASE] != NULL);
442 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
444 __progname = obj_rtld.path;
445 argv0 = argv[0] != NULL ? argv[0] : "(null)";
450 if (aux_info[AT_BSDFLAGS] != NULL &&
451 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0)
452 ld_fast_sigblock = true;
454 trust = !issetugid();
457 md_abi_variant_hook(aux_info);
460 if (aux_info[AT_EXECFD] != NULL) {
461 fd = aux_info[AT_EXECFD]->a_un.a_val;
463 assert(aux_info[AT_PHDR] != NULL);
464 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
465 if (phdr == obj_rtld.phdr) {
467 _rtld_error("Tainted process refusing to run binary %s",
473 dbg("opening main program in direct exec mode");
475 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, &argv0);
476 explicit_fd = (fd != -1);
479 fd = open_binary_fd(argv0, search_in_path, &binpath);
480 if (fstat(fd, &st) == -1) {
481 _rtld_error("Failed to fstat FD %d (%s): %s", fd,
482 explicit_fd ? "user-provided descriptor" : argv0,
483 rtld_strerror(errno));
488 * Rough emulation of the permission checks done by
489 * execve(2), only Unix DACs are checked, ACLs are
490 * ignored. Preserve the semantic of disabling owner
491 * to execute if owner x bit is cleared, even if
492 * others x bit is enabled.
493 * mmap(2) does not allow to mmap with PROT_EXEC if
494 * binary' file comes from noexec mount. We cannot
495 * set a text reference on the binary.
498 if (st.st_uid == geteuid()) {
499 if ((st.st_mode & S_IXUSR) != 0)
501 } else if (st.st_gid == getegid()) {
502 if ((st.st_mode & S_IXGRP) != 0)
504 } else if ((st.st_mode & S_IXOTH) != 0) {
508 _rtld_error("No execute permission for binary %s",
514 * For direct exec mode, argv[0] is the interpreter
515 * name, we must remove it and shift arguments left
516 * before invoking binary main. Since stack layout
517 * places environment pointers and aux vectors right
518 * after the terminating NULL, we must shift
519 * environment and aux as well.
521 main_argc = argc - rtld_argc;
522 for (i = 0; i <= main_argc; i++)
523 argv[i] = argv[i + rtld_argc];
525 environ = env = envp = argv + main_argc + 1;
526 dbg("move env from %p to %p", envp + rtld_argc, envp);
528 *envp = *(envp + rtld_argc);
529 } while (*envp++ != NULL);
530 aux = auxp = (Elf_Auxinfo *)envp;
531 auxpf = (Elf_Auxinfo *)(envp + rtld_argc);
532 dbg("move aux from %p to %p", auxpf, aux);
533 /* XXXKIB insert place for AT_EXECPATH if not present */
534 for (;; auxp++, auxpf++) {
536 if (auxp->a_type == AT_NULL)
539 /* Since the auxiliary vector has moved, redigest it. */
540 for (i = 0; i < AT_COUNT; i++)
542 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
543 if (auxp->a_type < AT_COUNT)
544 aux_info[auxp->a_type] = auxp;
547 /* Point AT_EXECPATH auxv and aux_info to the binary path. */
548 if (binpath == NULL) {
549 aux_info[AT_EXECPATH] = NULL;
551 if (aux_info[AT_EXECPATH] == NULL) {
552 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo));
553 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH;
555 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *,
559 _rtld_error("No binary");
565 ld_bind_now = getenv(_LD("BIND_NOW"));
568 * If the process is tainted, then we un-set the dangerous environment
569 * variables. The process will be marked as tainted until setuid(2)
570 * is called. If any child process calls setuid(2) we do not want any
571 * future processes to honor the potentially un-safe variables.
574 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) ||
575 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) ||
576 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) ||
577 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) ||
578 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) {
579 _rtld_error("environment corrupt; aborting");
583 ld_debug = getenv(_LD("DEBUG"));
584 if (ld_bind_now == NULL)
585 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL;
586 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL;
587 libmap_override = getenv(_LD("LIBMAP"));
588 ld_library_path = getenv(_LD("LIBRARY_PATH"));
589 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS"));
590 ld_preload = getenv(_LD("PRELOAD"));
591 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH"));
592 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL;
593 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH"));
594 if (library_path_rpath != NULL) {
595 if (library_path_rpath[0] == 'y' ||
596 library_path_rpath[0] == 'Y' ||
597 library_path_rpath[0] == '1')
598 ld_library_path_rpath = true;
600 ld_library_path_rpath = false;
602 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
603 (ld_library_path != NULL) || (ld_preload != NULL) ||
604 (ld_elf_hints_path != NULL) || ld_loadfltr;
605 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS"));
606 ld_utrace = getenv(_LD("UTRACE"));
608 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
609 ld_elf_hints_path = ld_elf_hints_default;
611 if (ld_debug != NULL && *ld_debug != '\0')
613 dbg("%s is initialized, base address = %p", __progname,
614 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
615 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
616 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
618 dbg("initializing thread locks");
622 * Load the main program, or process its program header if it is
625 if (fd != -1) { /* Load the main program. */
626 dbg("loading main program");
627 obj_main = map_object(fd, argv0, NULL);
629 if (obj_main == NULL)
631 max_stack_flags = obj_main->stack_flags;
632 } else { /* Main program already loaded. */
633 dbg("processing main program's program header");
634 assert(aux_info[AT_PHDR] != NULL);
635 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
636 assert(aux_info[AT_PHNUM] != NULL);
637 phnum = aux_info[AT_PHNUM]->a_un.a_val;
638 assert(aux_info[AT_PHENT] != NULL);
639 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
640 assert(aux_info[AT_ENTRY] != NULL);
641 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
642 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL)
646 if (aux_info[AT_EXECPATH] != NULL && fd == -1) {
647 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
648 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
649 if (kexecpath[0] == '/')
650 obj_main->path = kexecpath;
651 else if (getcwd(buf, sizeof(buf)) == NULL ||
652 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
653 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
654 obj_main->path = xstrdup(argv0);
656 obj_main->path = xstrdup(buf);
658 dbg("No AT_EXECPATH or direct exec");
659 obj_main->path = xstrdup(argv0);
661 dbg("obj_main path %s", obj_main->path);
662 obj_main->mainprog = true;
664 if (aux_info[AT_STACKPROT] != NULL &&
665 aux_info[AT_STACKPROT]->a_un.a_val != 0)
666 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
670 * Get the actual dynamic linker pathname from the executable if
671 * possible. (It should always be possible.) That ensures that
672 * gdb will find the right dynamic linker even if a non-standard
675 if (obj_main->interp != NULL &&
676 strcmp(obj_main->interp, obj_rtld.path) != 0) {
678 obj_rtld.path = xstrdup(obj_main->interp);
679 __progname = obj_rtld.path;
683 if (!digest_dynamic(obj_main, 0))
685 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
686 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
687 obj_main->dynsymcount);
689 linkmap_add(obj_main);
690 linkmap_add(&obj_rtld);
692 /* Link the main program into the list of objects. */
693 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
697 /* Initialize a fake symbol for resolving undefined weak references. */
698 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
699 sym_zero.st_shndx = SHN_UNDEF;
700 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
703 libmap_disable = (bool)lm_init(libmap_override);
705 dbg("loading LD_PRELOAD libraries");
706 if (load_preload_objects() == -1)
708 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
710 dbg("loading needed objects");
711 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE :
715 /* Make a list of all objects loaded at startup. */
716 last_interposer = obj_main;
717 TAILQ_FOREACH(obj, &obj_list, next) {
720 if (obj->z_interpose && obj != obj_main) {
721 objlist_put_after(&list_main, last_interposer, obj);
722 last_interposer = obj;
724 objlist_push_tail(&list_main, obj);
729 dbg("checking for required versions");
730 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
733 if (ld_tracing) { /* We're done */
734 trace_loaded_objects(obj_main);
738 if (getenv(_LD("DUMP_REL_PRE")) != NULL) {
739 dump_relocations(obj_main);
744 * Processing tls relocations requires having the tls offsets
745 * initialized. Prepare offsets before starting initial
746 * relocation processing.
748 dbg("initializing initial thread local storage offsets");
749 STAILQ_FOREACH(entry, &list_main, link) {
751 * Allocate all the initial objects out of the static TLS
752 * block even if they didn't ask for it.
754 allocate_tls_offset(entry->obj);
757 if (relocate_objects(obj_main,
758 ld_bind_now != NULL && *ld_bind_now != '\0',
759 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
762 dbg("doing copy relocations");
763 if (do_copy_relocations(obj_main) == -1)
766 if (getenv(_LD("DUMP_REL_POST")) != NULL) {
767 dump_relocations(obj_main);
774 * Setup TLS for main thread. This must be done after the
775 * relocations are processed, since tls initialization section
776 * might be the subject for relocations.
778 dbg("initializing initial thread local storage");
779 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
781 dbg("initializing key program variables");
782 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
783 set_program_var("environ", env);
784 set_program_var("__elf_aux_vector", aux);
786 /* Make a list of init functions to call. */
787 objlist_init(&initlist);
788 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)),
789 preload_tail, &initlist);
791 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
793 map_stacks_exec(NULL);
795 if (!obj_main->crt_no_init) {
797 * Make sure we don't call the main program's init and fini
798 * functions for binaries linked with old crt1 which calls
801 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
802 obj_main->preinit_array = obj_main->init_array =
803 obj_main->fini_array = (Elf_Addr)NULL;
807 * Execute MD initializers required before we call the objects'
813 /* Set osrel for direct-execed binary */
816 mib[2] = KERN_PROC_OSREL;
818 osrel = obj_main->osrel;
819 sz = sizeof(old_osrel);
820 dbg("setting osrel to %d", osrel);
821 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel));
824 wlock_acquire(rtld_bind_lock, &lockstate);
826 dbg("resolving ifuncs");
827 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL &&
828 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1)
831 rtld_exit_ptr = rtld_exit;
832 if (obj_main->crt_no_init)
834 objlist_call_init(&initlist, &lockstate);
835 _r_debug_postinit(&obj_main->linkmap);
836 objlist_clear(&initlist);
837 dbg("loading filtees");
838 TAILQ_FOREACH(obj, &obj_list, next) {
841 if (ld_loadfltr || obj->z_loadfltr)
842 load_filtees(obj, 0, &lockstate);
845 dbg("enforcing main obj relro");
846 if (obj_enforce_relro(obj_main) == -1)
849 lock_release(rtld_bind_lock, &lockstate);
851 dbg("transferring control to program entry point = %p", obj_main->entry);
853 /* Return the exit procedure and the program entry point. */
854 *exit_proc = rtld_exit_ptr;
856 return (func_ptr_type) obj_main->entry;
860 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
865 ptr = (void *)make_function_pointer(def, obj);
866 target = call_ifunc_resolver(ptr);
867 return ((void *)target);
871 * NB: MIPS uses a private version of this function (_mips_rtld_bind).
872 * Changes to this function should be applied there as well.
875 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
879 const Obj_Entry *defobj;
882 RtldLockState lockstate;
884 rlock_acquire(rtld_bind_lock, &lockstate);
885 if (sigsetjmp(lockstate.env, 0) != 0)
886 lock_upgrade(rtld_bind_lock, &lockstate);
888 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff);
890 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff);
892 where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
893 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
897 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
898 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
900 target = (Elf_Addr)(defobj->relocbase + def->st_value);
902 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
903 defobj->strtab + def->st_name, basename(obj->path),
904 (void *)target, basename(defobj->path));
907 * Write the new contents for the jmpslot. Note that depending on
908 * architecture, the value which we need to return back to the
909 * lazy binding trampoline may or may not be the target
910 * address. The value returned from reloc_jmpslot() is the value
911 * that the trampoline needs.
913 target = reloc_jmpslot(where, target, defobj, obj, rel);
914 lock_release(rtld_bind_lock, &lockstate);
919 * Error reporting function. Use it like printf. If formats the message
920 * into a buffer, and sets things up so that the next call to dlerror()
921 * will return the message.
924 _rtld_error(const char *fmt, ...)
926 static char buf[512];
930 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
933 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message);
937 * Return a dynamically-allocated copy of the current error message, if any.
942 return error_message == NULL ? NULL : xstrdup(error_message);
946 * Restore the current error message from a copy which was previously saved
947 * by errmsg_save(). The copy is freed.
950 errmsg_restore(char *saved_msg)
952 if (saved_msg == NULL)
953 error_message = NULL;
955 _rtld_error("%s", saved_msg);
961 basename(const char *name)
963 const char *p = strrchr(name, '/');
964 return p != NULL ? p + 1 : name;
967 static struct utsname uts;
970 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
971 const char *subst, bool may_free)
973 char *p, *p1, *res, *resp;
974 int subst_len, kw_len, subst_count, old_len, new_len;
979 * First, count the number of the keyword occurrences, to
980 * preallocate the final string.
982 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
989 * If the keyword is not found, just return.
991 * Return non-substituted string if resolution failed. We
992 * cannot do anything more reasonable, the failure mode of the
993 * caller is unresolved library anyway.
995 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
996 return (may_free ? real : xstrdup(real));
998 subst = obj->origin_path;
1001 * There is indeed something to substitute. Calculate the
1002 * length of the resulting string, and allocate it.
1004 subst_len = strlen(subst);
1005 old_len = strlen(real);
1006 new_len = old_len + (subst_len - kw_len) * subst_count;
1007 res = xmalloc(new_len + 1);
1010 * Now, execute the substitution loop.
1012 for (p = real, resp = res, *resp = '\0';;) {
1015 /* Copy the prefix before keyword. */
1016 memcpy(resp, p, p1 - p);
1018 /* Keyword replacement. */
1019 memcpy(resp, subst, subst_len);
1027 /* Copy to the end of string and finish. */
1035 origin_subst(Obj_Entry *obj, const char *real)
1037 char *res1, *res2, *res3, *res4;
1039 if (obj == NULL || !trust)
1040 return (xstrdup(real));
1041 if (uts.sysname[0] == '\0') {
1042 if (uname(&uts) != 0) {
1043 _rtld_error("utsname failed: %d", errno);
1047 /* __DECONST is safe here since without may_free real is unchanged */
1048 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL,
1050 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
1051 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
1052 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
1059 const char *msg = dlerror();
1062 msg = "Fatal error";
1063 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": ");
1064 rtld_fdputstr(STDERR_FILENO, msg);
1065 rtld_fdputchar(STDERR_FILENO, '\n');
1070 * Process a shared object's DYNAMIC section, and save the important
1071 * information in its Obj_Entry structure.
1074 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
1075 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
1077 const Elf_Dyn *dynp;
1078 Needed_Entry **needed_tail = &obj->needed;
1079 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
1080 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
1081 const Elf_Hashelt *hashtab;
1082 const Elf32_Word *hashval;
1083 Elf32_Word bkt, nmaskwords;
1085 int plttype = DT_REL;
1089 *dyn_runpath = NULL;
1091 obj->bind_now = false;
1092 dynp = obj->dynamic;
1095 for (; dynp->d_tag != DT_NULL; dynp++) {
1096 switch (dynp->d_tag) {
1099 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr);
1103 obj->relsize = dynp->d_un.d_val;
1107 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1111 obj->pltrel = (const Elf_Rel *)
1112 (obj->relocbase + dynp->d_un.d_ptr);
1116 obj->pltrelsize = dynp->d_un.d_val;
1120 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr);
1124 obj->relasize = dynp->d_un.d_val;
1128 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1132 plttype = dynp->d_un.d_val;
1133 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1137 obj->symtab = (const Elf_Sym *)
1138 (obj->relocbase + dynp->d_un.d_ptr);
1142 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1146 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr);
1150 obj->strsize = dynp->d_un.d_val;
1154 obj->verneed = (const Elf_Verneed *)(obj->relocbase +
1159 obj->verneednum = dynp->d_un.d_val;
1163 obj->verdef = (const Elf_Verdef *)(obj->relocbase +
1168 obj->verdefnum = dynp->d_un.d_val;
1172 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1178 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1180 obj->nbuckets = hashtab[0];
1181 obj->nchains = hashtab[1];
1182 obj->buckets = hashtab + 2;
1183 obj->chains = obj->buckets + obj->nbuckets;
1184 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1185 obj->buckets != NULL;
1191 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1193 obj->nbuckets_gnu = hashtab[0];
1194 obj->symndx_gnu = hashtab[1];
1195 nmaskwords = hashtab[2];
1196 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1197 obj->maskwords_bm_gnu = nmaskwords - 1;
1198 obj->shift2_gnu = hashtab[3];
1199 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4);
1200 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1201 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1203 /* Number of bitmask words is required to be power of 2 */
1204 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1205 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1211 Needed_Entry *nep = NEW(Needed_Entry);
1212 nep->name = dynp->d_un.d_val;
1217 needed_tail = &nep->next;
1223 Needed_Entry *nep = NEW(Needed_Entry);
1224 nep->name = dynp->d_un.d_val;
1228 *needed_filtees_tail = nep;
1229 needed_filtees_tail = &nep->next;
1231 if (obj->linkmap.l_refname == NULL)
1232 obj->linkmap.l_refname = (char *)dynp->d_un.d_val;
1238 Needed_Entry *nep = NEW(Needed_Entry);
1239 nep->name = dynp->d_un.d_val;
1243 *needed_aux_filtees_tail = nep;
1244 needed_aux_filtees_tail = &nep->next;
1249 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr);
1253 obj->textrel = true;
1257 obj->symbolic = true;
1262 * We have to wait until later to process this, because we
1263 * might not have gotten the address of the string table yet.
1273 *dyn_runpath = dynp;
1277 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1280 case DT_PREINIT_ARRAY:
1281 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1284 case DT_PREINIT_ARRAYSZ:
1285 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1289 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1292 case DT_INIT_ARRAYSZ:
1293 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1297 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1301 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1304 case DT_FINI_ARRAYSZ:
1305 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1309 * Don't process DT_DEBUG on MIPS as the dynamic section
1310 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1316 dbg("Filling in DT_DEBUG entry");
1317 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug;
1322 if (dynp->d_un.d_val & DF_ORIGIN)
1323 obj->z_origin = true;
1324 if (dynp->d_un.d_val & DF_SYMBOLIC)
1325 obj->symbolic = true;
1326 if (dynp->d_un.d_val & DF_TEXTREL)
1327 obj->textrel = true;
1328 if (dynp->d_un.d_val & DF_BIND_NOW)
1329 obj->bind_now = true;
1330 if (dynp->d_un.d_val & DF_STATIC_TLS)
1331 obj->static_tls = true;
1334 case DT_MIPS_LOCAL_GOTNO:
1335 obj->local_gotno = dynp->d_un.d_val;
1338 case DT_MIPS_SYMTABNO:
1339 obj->symtabno = dynp->d_un.d_val;
1342 case DT_MIPS_GOTSYM:
1343 obj->gotsym = dynp->d_un.d_val;
1346 case DT_MIPS_RLD_MAP:
1347 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1350 case DT_MIPS_RLD_MAP_REL:
1351 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map
1352 // section relative to the address of the tag itself.
1353 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) =
1354 (Elf_Addr) &r_debug;
1357 case DT_MIPS_PLTGOT:
1358 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase +
1365 #ifdef __powerpc64__
1366 case DT_PPC64_GLINK:
1367 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1371 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr);
1377 if (dynp->d_un.d_val & DF_1_NOOPEN)
1378 obj->z_noopen = true;
1379 if (dynp->d_un.d_val & DF_1_ORIGIN)
1380 obj->z_origin = true;
1381 if (dynp->d_un.d_val & DF_1_GLOBAL)
1382 obj->z_global = true;
1383 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1384 obj->bind_now = true;
1385 if (dynp->d_un.d_val & DF_1_NODELETE)
1386 obj->z_nodelete = true;
1387 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1388 obj->z_loadfltr = true;
1389 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1390 obj->z_interpose = true;
1391 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1392 obj->z_nodeflib = true;
1393 if (dynp->d_un.d_val & DF_1_PIE)
1399 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1406 obj->traced = false;
1408 if (plttype == DT_RELA) {
1409 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1411 obj->pltrelasize = obj->pltrelsize;
1412 obj->pltrelsize = 0;
1415 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1416 if (obj->valid_hash_sysv)
1417 obj->dynsymcount = obj->nchains;
1418 else if (obj->valid_hash_gnu) {
1419 obj->dynsymcount = 0;
1420 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1421 if (obj->buckets_gnu[bkt] == 0)
1423 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1426 while ((*hashval++ & 1u) == 0);
1428 obj->dynsymcount += obj->symndx_gnu;
1431 if (obj->linkmap.l_refname != NULL)
1432 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj->
1437 obj_resolve_origin(Obj_Entry *obj)
1440 if (obj->origin_path != NULL)
1442 obj->origin_path = xmalloc(PATH_MAX);
1443 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1447 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1448 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1451 if (obj->z_origin && !obj_resolve_origin(obj))
1454 if (dyn_runpath != NULL) {
1455 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val;
1456 obj->runpath = origin_subst(obj, obj->runpath);
1457 } else if (dyn_rpath != NULL) {
1458 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val;
1459 obj->rpath = origin_subst(obj, obj->rpath);
1461 if (dyn_soname != NULL)
1462 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1467 digest_dynamic(Obj_Entry *obj, int early)
1469 const Elf_Dyn *dyn_rpath;
1470 const Elf_Dyn *dyn_soname;
1471 const Elf_Dyn *dyn_runpath;
1473 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1474 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath));
1478 * Process a shared object's program header. This is used only for the
1479 * main program, when the kernel has already loaded the main program
1480 * into memory before calling the dynamic linker. It creates and
1481 * returns an Obj_Entry structure.
1484 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1487 const Elf_Phdr *phlimit = phdr + phnum;
1489 Elf_Addr note_start, note_end;
1493 for (ph = phdr; ph < phlimit; ph++) {
1494 if (ph->p_type != PT_PHDR)
1498 obj->phsize = ph->p_memsz;
1499 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr;
1503 obj->stack_flags = PF_X | PF_R | PF_W;
1505 for (ph = phdr; ph < phlimit; ph++) {
1506 switch (ph->p_type) {
1509 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1513 if (nsegs == 0) { /* First load segment */
1514 obj->vaddrbase = trunc_page(ph->p_vaddr);
1515 obj->mapbase = obj->vaddrbase + obj->relocbase;
1516 } else { /* Last load segment */
1517 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1524 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1529 obj->tlssize = ph->p_memsz;
1530 obj->tlsalign = ph->p_align;
1531 obj->tlsinitsize = ph->p_filesz;
1532 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1533 obj->tlspoffset = ph->p_offset;
1537 obj->stack_flags = ph->p_flags;
1541 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1542 obj->relro_size = round_page(ph->p_memsz);
1546 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1547 note_end = note_start + ph->p_filesz;
1548 digest_notes(obj, note_start, note_end);
1553 _rtld_error("%s: too few PT_LOAD segments", path);
1562 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1564 const Elf_Note *note;
1565 const char *note_name;
1568 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1569 note = (const Elf_Note *)((const char *)(note + 1) +
1570 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1571 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1572 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1573 note->n_descsz != sizeof(int32_t))
1575 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1576 note->n_type != NT_FREEBSD_FEATURE_CTL &&
1577 note->n_type != NT_FREEBSD_NOINIT_TAG)
1579 note_name = (const char *)(note + 1);
1580 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1581 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1583 switch (note->n_type) {
1584 case NT_FREEBSD_ABI_TAG:
1585 /* FreeBSD osrel note */
1586 p = (uintptr_t)(note + 1);
1587 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1588 obj->osrel = *(const int32_t *)(p);
1589 dbg("note osrel %d", obj->osrel);
1591 case NT_FREEBSD_FEATURE_CTL:
1592 /* FreeBSD ABI feature control note */
1593 p = (uintptr_t)(note + 1);
1594 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1595 obj->fctl0 = *(const uint32_t *)(p);
1596 dbg("note fctl0 %#x", obj->fctl0);
1598 case NT_FREEBSD_NOINIT_TAG:
1599 /* FreeBSD 'crt does not call init' note */
1600 obj->crt_no_init = true;
1601 dbg("note crt_no_init");
1608 dlcheck(void *handle)
1612 TAILQ_FOREACH(obj, &obj_list, next) {
1613 if (obj == (Obj_Entry *) handle)
1617 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1618 _rtld_error("Invalid shared object handle %p", handle);
1625 * If the given object is already in the donelist, return true. Otherwise
1626 * add the object to the list and return false.
1629 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1633 for (i = 0; i < dlp->num_used; i++)
1634 if (dlp->objs[i] == obj)
1637 * Our donelist allocation should always be sufficient. But if
1638 * our threads locking isn't working properly, more shared objects
1639 * could have been loaded since we allocated the list. That should
1640 * never happen, but we'll handle it properly just in case it does.
1642 if (dlp->num_used < dlp->num_alloc)
1643 dlp->objs[dlp->num_used++] = obj;
1648 * Hash function for symbol table lookup. Don't even think about changing
1649 * this. It is specified by the System V ABI.
1652 elf_hash(const char *name)
1654 const unsigned char *p = (const unsigned char *) name;
1655 unsigned long h = 0;
1658 while (*p != '\0') {
1659 h = (h << 4) + *p++;
1660 if ((g = h & 0xf0000000) != 0)
1668 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1669 * unsigned in case it's implemented with a wider type.
1672 gnu_hash(const char *s)
1678 for (c = *s; c != '\0'; c = *++s)
1680 return (h & 0xffffffff);
1685 * Find the library with the given name, and return its full pathname.
1686 * The returned string is dynamically allocated. Generates an error
1687 * message and returns NULL if the library cannot be found.
1689 * If the second argument is non-NULL, then it refers to an already-
1690 * loaded shared object, whose library search path will be searched.
1692 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1693 * descriptor (which is close-on-exec) will be passed out via the third
1696 * The search order is:
1697 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1698 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1700 * DT_RUNPATH in the referencing file
1701 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1703 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1705 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1708 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1710 char *pathname, *refobj_path;
1712 bool nodeflib, objgiven;
1714 objgiven = refobj != NULL;
1716 if (libmap_disable || !objgiven ||
1717 (name = lm_find(refobj->path, xname)) == NULL)
1720 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1721 if (name[0] != '/' && !trust) {
1722 _rtld_error("Absolute pathname required "
1723 "for shared object \"%s\"", name);
1726 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1727 __DECONST(char *, name)));
1730 dbg(" Searching for \"%s\"", name);
1731 refobj_path = objgiven ? refobj->path : NULL;
1734 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1735 * back to pre-conforming behaviour if user requested so with
1736 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1739 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1740 pathname = search_library_path(name, ld_library_path,
1742 if (pathname != NULL)
1744 if (refobj != NULL) {
1745 pathname = search_library_path(name, refobj->rpath,
1747 if (pathname != NULL)
1750 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1751 if (pathname != NULL)
1753 pathname = search_library_path(name, gethints(false),
1755 if (pathname != NULL)
1757 pathname = search_library_path(name, ld_standard_library_path,
1759 if (pathname != NULL)
1762 nodeflib = objgiven ? refobj->z_nodeflib : false;
1764 pathname = search_library_path(name, refobj->rpath,
1766 if (pathname != NULL)
1769 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1770 pathname = search_library_path(name, obj_main->rpath,
1772 if (pathname != NULL)
1775 pathname = search_library_path(name, ld_library_path,
1777 if (pathname != NULL)
1780 pathname = search_library_path(name, refobj->runpath,
1782 if (pathname != NULL)
1785 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1786 if (pathname != NULL)
1788 pathname = search_library_path(name, gethints(nodeflib),
1790 if (pathname != NULL)
1792 if (objgiven && !nodeflib) {
1793 pathname = search_library_path(name,
1794 ld_standard_library_path, refobj_path, fdp);
1795 if (pathname != NULL)
1800 if (objgiven && refobj->path != NULL) {
1801 _rtld_error("Shared object \"%s\" not found, "
1802 "required by \"%s\"", name, basename(refobj->path));
1804 _rtld_error("Shared object \"%s\" not found", name);
1810 * Given a symbol number in a referencing object, find the corresponding
1811 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1812 * no definition was found. Returns a pointer to the Obj_Entry of the
1813 * defining object via the reference parameter DEFOBJ_OUT.
1816 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1817 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1818 RtldLockState *lockstate)
1822 const Obj_Entry *defobj;
1823 const Ver_Entry *ve;
1829 * If we have already found this symbol, get the information from
1832 if (symnum >= refobj->dynsymcount)
1833 return NULL; /* Bad object */
1834 if (cache != NULL && cache[symnum].sym != NULL) {
1835 *defobj_out = cache[symnum].obj;
1836 return cache[symnum].sym;
1839 ref = refobj->symtab + symnum;
1840 name = refobj->strtab + ref->st_name;
1846 * We don't have to do a full scale lookup if the symbol is local.
1847 * We know it will bind to the instance in this load module; to
1848 * which we already have a pointer (ie ref). By not doing a lookup,
1849 * we not only improve performance, but it also avoids unresolvable
1850 * symbols when local symbols are not in the hash table. This has
1851 * been seen with the ia64 toolchain.
1853 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1854 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1855 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1858 symlook_init(&req, name);
1860 ve = req.ventry = fetch_ventry(refobj, symnum);
1861 req.lockstate = lockstate;
1862 res = symlook_default(&req, refobj);
1865 defobj = req.defobj_out;
1873 * If we found no definition and the reference is weak, treat the
1874 * symbol as having the value zero.
1876 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1882 *defobj_out = defobj;
1883 /* Record the information in the cache to avoid subsequent lookups. */
1884 if (cache != NULL) {
1885 cache[symnum].sym = def;
1886 cache[symnum].obj = defobj;
1889 if (refobj != &obj_rtld)
1890 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name,
1891 ve != NULL ? "@" : "", ve != NULL ? ve->name : "");
1897 * Return the search path from the ldconfig hints file, reading it if
1898 * necessary. If nostdlib is true, then the default search paths are
1899 * not added to result.
1901 * Returns NULL if there are problems with the hints file,
1902 * or if the search path there is empty.
1905 gethints(bool nostdlib)
1907 static char *filtered_path;
1908 static const char *hints;
1909 static struct elfhints_hdr hdr;
1910 struct fill_search_info_args sargs, hargs;
1911 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1912 struct dl_serpath *SLPpath, *hintpath;
1914 struct stat hint_stat;
1915 unsigned int SLPndx, hintndx, fndx, fcount;
1921 /* First call, read the hints file */
1922 if (hints == NULL) {
1923 /* Keep from trying again in case the hints file is bad. */
1926 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1930 * Check of hdr.dirlistlen value against type limit
1931 * intends to pacify static analyzers. Further
1932 * paranoia leads to checks that dirlist is fully
1933 * contained in the file range.
1935 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1936 hdr.magic != ELFHINTS_MAGIC ||
1937 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 ||
1938 fstat(fd, &hint_stat) == -1) {
1945 if (dl + hdr.dirlist < dl)
1948 if (dl + hdr.dirlistlen < dl)
1950 dl += hdr.dirlistlen;
1951 if (dl > hint_stat.st_size)
1953 p = xmalloc(hdr.dirlistlen + 1);
1954 if (pread(fd, p, hdr.dirlistlen + 1,
1955 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 ||
1956 p[hdr.dirlistlen] != '\0') {
1965 * If caller agreed to receive list which includes the default
1966 * paths, we are done. Otherwise, if we still did not
1967 * calculated filtered result, do it now.
1970 return (hints[0] != '\0' ? hints : NULL);
1971 if (filtered_path != NULL)
1975 * Obtain the list of all configured search paths, and the
1976 * list of the default paths.
1978 * First estimate the size of the results.
1980 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1982 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1985 sargs.request = RTLD_DI_SERINFOSIZE;
1986 sargs.serinfo = &smeta;
1987 hargs.request = RTLD_DI_SERINFOSIZE;
1988 hargs.serinfo = &hmeta;
1990 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1992 path_enumerate(hints, fill_search_info, NULL, &hargs);
1994 SLPinfo = xmalloc(smeta.dls_size);
1995 hintinfo = xmalloc(hmeta.dls_size);
1998 * Next fetch both sets of paths.
2000 sargs.request = RTLD_DI_SERINFO;
2001 sargs.serinfo = SLPinfo;
2002 sargs.serpath = &SLPinfo->dls_serpath[0];
2003 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
2005 hargs.request = RTLD_DI_SERINFO;
2006 hargs.serinfo = hintinfo;
2007 hargs.serpath = &hintinfo->dls_serpath[0];
2008 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
2010 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
2012 path_enumerate(hints, fill_search_info, NULL, &hargs);
2015 * Now calculate the difference between two sets, by excluding
2016 * standard paths from the full set.
2020 filtered_path = xmalloc(hdr.dirlistlen + 1);
2021 hintpath = &hintinfo->dls_serpath[0];
2022 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
2024 SLPpath = &SLPinfo->dls_serpath[0];
2026 * Check each standard path against current.
2028 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
2029 /* matched, skip the path */
2030 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
2038 * Not matched against any standard path, add the path
2039 * to result. Separate consequtive paths with ':'.
2042 filtered_path[fndx] = ':';
2046 flen = strlen(hintpath->dls_name);
2047 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
2050 filtered_path[fndx] = '\0';
2056 return (filtered_path[0] != '\0' ? filtered_path : NULL);
2060 init_dag(Obj_Entry *root)
2062 const Needed_Entry *needed;
2063 const Objlist_Entry *elm;
2066 if (root->dag_inited)
2068 donelist_init(&donelist);
2070 /* Root object belongs to own DAG. */
2071 objlist_push_tail(&root->dldags, root);
2072 objlist_push_tail(&root->dagmembers, root);
2073 donelist_check(&donelist, root);
2076 * Add dependencies of root object to DAG in breadth order
2077 * by exploiting the fact that each new object get added
2078 * to the tail of the dagmembers list.
2080 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2081 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
2082 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
2084 objlist_push_tail(&needed->obj->dldags, root);
2085 objlist_push_tail(&root->dagmembers, needed->obj);
2088 root->dag_inited = true;
2092 init_marker(Obj_Entry *marker)
2095 bzero(marker, sizeof(*marker));
2096 marker->marker = true;
2100 globallist_curr(const Obj_Entry *obj)
2107 return (__DECONST(Obj_Entry *, obj));
2108 obj = TAILQ_PREV(obj, obj_entry_q, next);
2113 globallist_next(const Obj_Entry *obj)
2117 obj = TAILQ_NEXT(obj, next);
2121 return (__DECONST(Obj_Entry *, obj));
2125 /* Prevent the object from being unmapped while the bind lock is dropped. */
2127 hold_object(Obj_Entry *obj)
2134 unhold_object(Obj_Entry *obj)
2137 assert(obj->holdcount > 0);
2138 if (--obj->holdcount == 0 && obj->unholdfree)
2139 release_object(obj);
2143 process_z(Obj_Entry *root)
2145 const Objlist_Entry *elm;
2149 * Walk over object DAG and process every dependent object
2150 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2151 * to grow their own DAG.
2153 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2154 * symlook_global() to work.
2156 * For DF_1_NODELETE, the DAG should have its reference upped.
2158 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2162 if (obj->z_nodelete && !obj->ref_nodel) {
2163 dbg("obj %s -z nodelete", obj->path);
2166 obj->ref_nodel = true;
2168 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2169 dbg("obj %s -z global", obj->path);
2170 objlist_push_tail(&list_global, obj);
2177 parse_rtld_phdr(Obj_Entry *obj)
2180 Elf_Addr note_start, note_end;
2182 obj->stack_flags = PF_X | PF_R | PF_W;
2183 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr +
2184 obj->phsize; ph++) {
2185 switch (ph->p_type) {
2187 obj->stack_flags = ph->p_flags;
2190 obj->relro_page = obj->relocbase +
2191 trunc_page(ph->p_vaddr);
2192 obj->relro_size = round_page(ph->p_memsz);
2195 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
2196 note_end = note_start + ph->p_filesz;
2197 digest_notes(obj, note_start, note_end);
2204 * Initialize the dynamic linker. The argument is the address at which
2205 * the dynamic linker has been mapped into memory. The primary task of
2206 * this function is to relocate the dynamic linker.
2209 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2211 Obj_Entry objtmp; /* Temporary rtld object */
2212 const Elf_Ehdr *ehdr;
2213 const Elf_Dyn *dyn_rpath;
2214 const Elf_Dyn *dyn_soname;
2215 const Elf_Dyn *dyn_runpath;
2217 #ifdef RTLD_INIT_PAGESIZES_EARLY
2218 /* The page size is required by the dynamic memory allocator. */
2219 init_pagesizes(aux_info);
2223 * Conjure up an Obj_Entry structure for the dynamic linker.
2225 * The "path" member can't be initialized yet because string constants
2226 * cannot yet be accessed. Below we will set it correctly.
2228 memset(&objtmp, 0, sizeof(objtmp));
2231 objtmp.mapbase = mapbase;
2233 objtmp.relocbase = mapbase;
2236 objtmp.dynamic = rtld_dynamic(&objtmp);
2237 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2238 assert(objtmp.needed == NULL);
2239 #if !defined(__mips__)
2240 /* MIPS has a bogus DT_TEXTREL. */
2241 assert(!objtmp.textrel);
2244 * Temporarily put the dynamic linker entry into the object list, so
2245 * that symbols can be found.
2247 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2249 ehdr = (Elf_Ehdr *)mapbase;
2250 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2251 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]);
2253 /* Initialize the object list. */
2254 TAILQ_INIT(&obj_list);
2256 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2257 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2259 #ifndef RTLD_INIT_PAGESIZES_EARLY
2260 /* The page size is required by the dynamic memory allocator. */
2261 init_pagesizes(aux_info);
2264 if (aux_info[AT_OSRELDATE] != NULL)
2265 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2267 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2269 /* Replace the path with a dynamically allocated copy. */
2270 obj_rtld.path = xstrdup(ld_path_rtld);
2272 parse_rtld_phdr(&obj_rtld);
2273 obj_enforce_relro(&obj_rtld);
2275 r_debug.r_brk = r_debug_state;
2276 r_debug.r_state = RT_CONSISTENT;
2280 * Retrieve the array of supported page sizes. The kernel provides the page
2281 * sizes in increasing order.
2284 init_pagesizes(Elf_Auxinfo **aux_info)
2286 static size_t psa[MAXPAGESIZES];
2290 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
2292 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2293 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2296 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2299 /* As a fallback, retrieve the base page size. */
2300 size = sizeof(psa[0]);
2301 if (aux_info[AT_PAGESZ] != NULL) {
2302 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2306 mib[1] = HW_PAGESIZE;
2310 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2311 _rtld_error("sysctl for hw.pagesize(s) failed");
2317 npagesizes = size / sizeof(pagesizes[0]);
2318 /* Discard any invalid entries at the end of the array. */
2319 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2324 * Add the init functions from a needed object list (and its recursive
2325 * needed objects) to "list". This is not used directly; it is a helper
2326 * function for initlist_add_objects(). The write lock must be held
2327 * when this function is called.
2330 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
2332 /* Recursively process the successor needed objects. */
2333 if (needed->next != NULL)
2334 initlist_add_neededs(needed->next, list);
2336 /* Process the current needed object. */
2337 if (needed->obj != NULL)
2338 initlist_add_objects(needed->obj, needed->obj, list);
2342 * Scan all of the DAGs rooted in the range of objects from "obj" to
2343 * "tail" and add their init functions to "list". This recurses over
2344 * the DAGs and ensure the proper init ordering such that each object's
2345 * needed libraries are initialized before the object itself. At the
2346 * same time, this function adds the objects to the global finalization
2347 * list "list_fini" in the opposite order. The write lock must be
2348 * held when this function is called.
2351 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2355 if (obj->init_scanned || obj->init_done)
2357 obj->init_scanned = true;
2359 /* Recursively process the successor objects. */
2360 nobj = globallist_next(obj);
2361 if (nobj != NULL && obj != tail)
2362 initlist_add_objects(nobj, tail, list);
2364 /* Recursively process the needed objects. */
2365 if (obj->needed != NULL)
2366 initlist_add_neededs(obj->needed, list);
2367 if (obj->needed_filtees != NULL)
2368 initlist_add_neededs(obj->needed_filtees, list);
2369 if (obj->needed_aux_filtees != NULL)
2370 initlist_add_neededs(obj->needed_aux_filtees, list);
2372 /* Add the object to the init list. */
2373 objlist_push_tail(list, obj);
2375 /* Add the object to the global fini list in the reverse order. */
2376 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2377 && !obj->on_fini_list) {
2378 objlist_push_head(&list_fini, obj);
2379 obj->on_fini_list = true;
2384 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2388 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2390 Needed_Entry *needed, *needed1;
2392 for (needed = n; needed != NULL; needed = needed->next) {
2393 if (needed->obj != NULL) {
2394 dlclose_locked(needed->obj, lockstate);
2398 for (needed = n; needed != NULL; needed = needed1) {
2399 needed1 = needed->next;
2405 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2408 free_needed_filtees(obj->needed_filtees, lockstate);
2409 obj->needed_filtees = NULL;
2410 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2411 obj->needed_aux_filtees = NULL;
2412 obj->filtees_loaded = false;
2416 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2417 RtldLockState *lockstate)
2420 for (; needed != NULL; needed = needed->next) {
2421 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2422 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2423 RTLD_LOCAL, lockstate);
2428 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2431 lock_restart_for_upgrade(lockstate);
2432 if (!obj->filtees_loaded) {
2433 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2434 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2435 obj->filtees_loaded = true;
2440 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2444 for (; needed != NULL; needed = needed->next) {
2445 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2446 flags & ~RTLD_LO_NOLOAD);
2447 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2454 * Given a shared object, traverse its list of needed objects, and load
2455 * each of them. Returns 0 on success. Generates an error message and
2456 * returns -1 on failure.
2459 load_needed_objects(Obj_Entry *first, int flags)
2463 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2466 if (process_needed(obj, obj->needed, flags) == -1)
2473 load_preload_objects(void)
2475 char *p = ld_preload;
2477 static const char delim[] = " \t:;";
2482 p += strspn(p, delim);
2483 while (*p != '\0') {
2484 size_t len = strcspn(p, delim);
2489 obj = load_object(p, -1, NULL, 0);
2491 return -1; /* XXX - cleanup */
2492 obj->z_interpose = true;
2495 p += strspn(p, delim);
2497 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2502 printable_path(const char *path)
2505 return (path == NULL ? "<unknown>" : path);
2509 * Load a shared object into memory, if it is not already loaded. The
2510 * object may be specified by name or by user-supplied file descriptor
2511 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2514 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2518 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2527 TAILQ_FOREACH(obj, &obj_list, next) {
2528 if (obj->marker || obj->doomed)
2530 if (object_match_name(obj, name))
2534 path = find_library(name, refobj, &fd);
2542 * search_library_pathfds() opens a fresh file descriptor for the
2543 * library, so there is no need to dup().
2545 } else if (fd_u == -1) {
2547 * If we didn't find a match by pathname, or the name is not
2548 * supplied, open the file and check again by device and inode.
2549 * This avoids false mismatches caused by multiple links or ".."
2552 * To avoid a race, we open the file and use fstat() rather than
2555 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2556 _rtld_error("Cannot open \"%s\"", path);
2561 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2563 _rtld_error("Cannot dup fd");
2568 if (fstat(fd, &sb) == -1) {
2569 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2574 TAILQ_FOREACH(obj, &obj_list, next) {
2575 if (obj->marker || obj->doomed)
2577 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2580 if (obj != NULL && name != NULL) {
2581 object_add_name(obj, name);
2586 if (flags & RTLD_LO_NOLOAD) {
2592 /* First use of this object, so we must map it in */
2593 obj = do_load_object(fd, name, path, &sb, flags);
2602 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2609 * but first, make sure that environment variables haven't been
2610 * used to circumvent the noexec flag on a filesystem.
2612 if (dangerous_ld_env) {
2613 if (fstatfs(fd, &fs) != 0) {
2614 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2617 if (fs.f_flags & MNT_NOEXEC) {
2618 _rtld_error("Cannot execute objects on %s", fs.f_mntonname);
2622 dbg("loading \"%s\"", printable_path(path));
2623 obj = map_object(fd, printable_path(path), sbp);
2628 * If DT_SONAME is present in the object, digest_dynamic2 already
2629 * added it to the object names.
2632 object_add_name(obj, name);
2634 if (!digest_dynamic(obj, 0))
2636 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2637 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2638 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) {
2639 dbg("refusing to load PIE executable \"%s\"", obj->path);
2640 _rtld_error("Cannot load PIE binary %s as DSO", obj->path);
2643 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2645 dbg("refusing to load non-loadable \"%s\"", obj->path);
2646 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2650 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2651 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2654 linkmap_add(obj); /* for GDB & dlinfo() */
2655 max_stack_flags |= obj->stack_flags;
2657 dbg(" %p .. %p: %s", obj->mapbase,
2658 obj->mapbase + obj->mapsize - 1, obj->path);
2660 dbg(" WARNING: %s has impure text", obj->path);
2661 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2667 munmap(obj->mapbase, obj->mapsize);
2673 obj_from_addr(const void *addr)
2677 TAILQ_FOREACH(obj, &obj_list, next) {
2680 if (addr < (void *) obj->mapbase)
2682 if (addr < (void *)(obj->mapbase + obj->mapsize))
2691 Elf_Addr *preinit_addr;
2694 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2695 if (preinit_addr == NULL)
2698 for (index = 0; index < obj_main->preinit_array_num; index++) {
2699 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2700 dbg("calling preinit function for %s at %p", obj_main->path,
2701 (void *)preinit_addr[index]);
2702 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2703 0, 0, obj_main->path);
2704 call_init_pointer(obj_main, preinit_addr[index]);
2710 * Call the finalization functions for each of the objects in "list"
2711 * belonging to the DAG of "root" and referenced once. If NULL "root"
2712 * is specified, every finalization function will be called regardless
2713 * of the reference count and the list elements won't be freed. All of
2714 * the objects are expected to have non-NULL fini functions.
2717 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2721 Elf_Addr *fini_addr;
2724 assert(root == NULL || root->refcount == 1);
2727 root->doomed = true;
2730 * Preserve the current error message since a fini function might
2731 * call into the dynamic linker and overwrite it.
2733 saved_msg = errmsg_save();
2735 STAILQ_FOREACH(elm, list, link) {
2736 if (root != NULL && (elm->obj->refcount != 1 ||
2737 objlist_find(&root->dagmembers, elm->obj) == NULL))
2739 /* Remove object from fini list to prevent recursive invocation. */
2740 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2741 /* Ensure that new references cannot be acquired. */
2742 elm->obj->doomed = true;
2744 hold_object(elm->obj);
2745 lock_release(rtld_bind_lock, lockstate);
2747 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2748 * When this happens, DT_FINI_ARRAY is processed first.
2750 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2751 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2752 for (index = elm->obj->fini_array_num - 1; index >= 0;
2754 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2755 dbg("calling fini function for %s at %p",
2756 elm->obj->path, (void *)fini_addr[index]);
2757 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2758 (void *)fini_addr[index], 0, 0, elm->obj->path);
2759 call_initfini_pointer(elm->obj, fini_addr[index]);
2763 if (elm->obj->fini != (Elf_Addr)NULL) {
2764 dbg("calling fini function for %s at %p", elm->obj->path,
2765 (void *)elm->obj->fini);
2766 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2767 0, 0, elm->obj->path);
2768 call_initfini_pointer(elm->obj, elm->obj->fini);
2770 wlock_acquire(rtld_bind_lock, lockstate);
2771 unhold_object(elm->obj);
2772 /* No need to free anything if process is going down. */
2776 * We must restart the list traversal after every fini call
2777 * because a dlclose() call from the fini function or from
2778 * another thread might have modified the reference counts.
2782 } while (elm != NULL);
2783 errmsg_restore(saved_msg);
2787 * Call the initialization functions for each of the objects in
2788 * "list". All of the objects are expected to have non-NULL init
2792 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2797 Elf_Addr *init_addr;
2798 void (*reg)(void (*)(void));
2802 * Clean init_scanned flag so that objects can be rechecked and
2803 * possibly initialized earlier if any of vectors called below
2804 * cause the change by using dlopen.
2806 TAILQ_FOREACH(obj, &obj_list, next) {
2809 obj->init_scanned = false;
2813 * Preserve the current error message since an init function might
2814 * call into the dynamic linker and overwrite it.
2816 saved_msg = errmsg_save();
2817 STAILQ_FOREACH(elm, list, link) {
2818 if (elm->obj->init_done) /* Initialized early. */
2821 * Race: other thread might try to use this object before current
2822 * one completes the initialization. Not much can be done here
2823 * without better locking.
2825 elm->obj->init_done = true;
2826 hold_object(elm->obj);
2828 if (elm->obj == obj_main && obj_main->crt_no_init) {
2829 reg = (void (*)(void (*)(void)))get_program_var_addr(
2830 "__libc_atexit", lockstate);
2832 lock_release(rtld_bind_lock, lockstate);
2835 rtld_exit_ptr = rtld_nop_exit;
2839 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2840 * When this happens, DT_INIT is processed first.
2842 if (elm->obj->init != (Elf_Addr)NULL) {
2843 dbg("calling init function for %s at %p", elm->obj->path,
2844 (void *)elm->obj->init);
2845 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2846 0, 0, elm->obj->path);
2847 call_init_pointer(elm->obj, elm->obj->init);
2849 init_addr = (Elf_Addr *)elm->obj->init_array;
2850 if (init_addr != NULL) {
2851 for (index = 0; index < elm->obj->init_array_num; index++) {
2852 if (init_addr[index] != 0 && init_addr[index] != 1) {
2853 dbg("calling init function for %s at %p", elm->obj->path,
2854 (void *)init_addr[index]);
2855 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2856 (void *)init_addr[index], 0, 0, elm->obj->path);
2857 call_init_pointer(elm->obj, init_addr[index]);
2861 wlock_acquire(rtld_bind_lock, lockstate);
2862 unhold_object(elm->obj);
2864 errmsg_restore(saved_msg);
2868 objlist_clear(Objlist *list)
2872 while (!STAILQ_EMPTY(list)) {
2873 elm = STAILQ_FIRST(list);
2874 STAILQ_REMOVE_HEAD(list, link);
2879 static Objlist_Entry *
2880 objlist_find(Objlist *list, const Obj_Entry *obj)
2884 STAILQ_FOREACH(elm, list, link)
2885 if (elm->obj == obj)
2891 objlist_init(Objlist *list)
2897 objlist_push_head(Objlist *list, Obj_Entry *obj)
2901 elm = NEW(Objlist_Entry);
2903 STAILQ_INSERT_HEAD(list, elm, link);
2907 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2911 elm = NEW(Objlist_Entry);
2913 STAILQ_INSERT_TAIL(list, elm, link);
2917 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2919 Objlist_Entry *elm, *listelm;
2921 STAILQ_FOREACH(listelm, list, link) {
2922 if (listelm->obj == listobj)
2925 elm = NEW(Objlist_Entry);
2927 if (listelm != NULL)
2928 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2930 STAILQ_INSERT_TAIL(list, elm, link);
2934 objlist_remove(Objlist *list, Obj_Entry *obj)
2938 if ((elm = objlist_find(list, obj)) != NULL) {
2939 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2945 * Relocate dag rooted in the specified object.
2946 * Returns 0 on success, or -1 on failure.
2950 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2951 int flags, RtldLockState *lockstate)
2957 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2958 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2967 * Prepare for, or clean after, relocating an object marked with
2968 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
2969 * segments are remapped read-write. After relocations are done, the
2970 * segment's permissions are returned back to the modes specified in
2971 * the phdrs. If any relocation happened, or always for wired
2972 * program, COW is triggered.
2975 reloc_textrel_prot(Obj_Entry *obj, bool before)
2982 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
2984 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
2986 base = obj->relocbase + trunc_page(ph->p_vaddr);
2987 sz = round_page(ph->p_vaddr + ph->p_filesz) -
2988 trunc_page(ph->p_vaddr);
2989 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0);
2990 if (mprotect(base, sz, prot) == -1) {
2991 _rtld_error("%s: Cannot write-%sable text segment: %s",
2992 obj->path, before ? "en" : "dis",
2993 rtld_strerror(errno));
3001 * Relocate single object.
3002 * Returns 0 on success, or -1 on failure.
3005 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
3006 int flags, RtldLockState *lockstate)
3011 obj->relocated = true;
3013 dbg("relocating \"%s\"", obj->path);
3015 if (obj->symtab == NULL || obj->strtab == NULL ||
3016 !(obj->valid_hash_sysv || obj->valid_hash_gnu))
3017 dbg("object %s has no run-time symbol table", obj->path);
3019 /* There are relocations to the write-protected text segment. */
3020 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
3023 /* Process the non-PLT non-IFUNC relocations. */
3024 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
3027 /* Re-protected the text segment. */
3028 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
3031 /* Set the special PLT or GOT entries. */
3034 /* Process the PLT relocations. */
3035 if (reloc_plt(obj, flags, lockstate) == -1)
3037 /* Relocate the jump slots if we are doing immediate binding. */
3038 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags,
3042 if (!obj->mainprog && obj_enforce_relro(obj) == -1)
3046 * Set up the magic number and version in the Obj_Entry. These
3047 * were checked in the crt1.o from the original ElfKit, so we
3048 * set them for backward compatibility.
3050 obj->magic = RTLD_MAGIC;
3051 obj->version = RTLD_VERSION;
3057 * Relocate newly-loaded shared objects. The argument is a pointer to
3058 * the Obj_Entry for the first such object. All objects from the first
3059 * to the end of the list of objects are relocated. Returns 0 on success,
3063 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
3064 int flags, RtldLockState *lockstate)
3069 for (error = 0, obj = first; obj != NULL;
3070 obj = TAILQ_NEXT(obj, next)) {
3073 error = relocate_object(obj, bind_now, rtldobj, flags,
3082 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
3083 * referencing STT_GNU_IFUNC symbols is postponed till the other
3084 * relocations are done. The indirect functions specified as
3085 * ifunc are allowed to call other symbols, so we need to have
3086 * objects relocated before asking for resolution from indirects.
3088 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
3089 * instead of the usual lazy handling of PLT slots. It is
3090 * consistent with how GNU does it.
3093 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
3094 RtldLockState *lockstate)
3097 if (obj->ifuncs_resolved)
3099 obj->ifuncs_resolved = true;
3100 if (!obj->irelative && !obj->irelative_nonplt &&
3101 !((obj->bind_now || bind_now) && obj->gnu_ifunc) &&
3102 !obj->non_plt_gnu_ifunc)
3104 if (obj_disable_relro(obj) == -1 ||
3105 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) ||
3106 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj,
3107 lockstate) == -1) ||
3108 ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
3109 reloc_gnu_ifunc(obj, flags, lockstate) == -1) ||
3110 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld,
3111 flags | SYMLOOK_IFUNC, lockstate) == -1) ||
3112 obj_enforce_relro(obj) == -1)
3118 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
3119 RtldLockState *lockstate)
3124 STAILQ_FOREACH(elm, list, link) {
3128 if (resolve_object_ifunc(obj, bind_now, flags,
3136 * Cleanup procedure. It will be called (by the atexit mechanism) just
3137 * before the process exits.
3142 RtldLockState lockstate;
3144 wlock_acquire(rtld_bind_lock, &lockstate);
3146 objlist_call_fini(&list_fini, NULL, &lockstate);
3147 /* No need to remove the items from the list, since we are exiting. */
3148 if (!libmap_disable)
3150 lock_release(rtld_bind_lock, &lockstate);
3159 * Iterate over a search path, translate each element, and invoke the
3160 * callback on the result.
3163 path_enumerate(const char *path, path_enum_proc callback,
3164 const char *refobj_path, void *arg)
3170 path += strspn(path, ":;");
3171 while (*path != '\0') {
3175 len = strcspn(path, ":;");
3176 trans = lm_findn(refobj_path, path, len);
3178 res = callback(trans, strlen(trans), arg);
3180 res = callback(path, len, arg);
3186 path += strspn(path, ":;");
3192 struct try_library_args {
3201 try_library_path(const char *dir, size_t dirlen, void *param)
3203 struct try_library_args *arg;
3207 if (*dir == '/' || trust) {
3210 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3213 pathname = arg->buffer;
3214 strncpy(pathname, dir, dirlen);
3215 pathname[dirlen] = '/';
3216 strcpy(pathname + dirlen + 1, arg->name);
3218 dbg(" Trying \"%s\"", pathname);
3219 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3221 dbg(" Opened \"%s\", fd %d", pathname, fd);
3222 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3223 strcpy(pathname, arg->buffer);
3227 dbg(" Failed to open \"%s\": %s",
3228 pathname, rtld_strerror(errno));
3235 search_library_path(const char *name, const char *path,
3236 const char *refobj_path, int *fdp)
3239 struct try_library_args arg;
3245 arg.namelen = strlen(name);
3246 arg.buffer = xmalloc(PATH_MAX);
3247 arg.buflen = PATH_MAX;
3250 p = path_enumerate(path, try_library_path, refobj_path, &arg);
3260 * Finds the library with the given name using the directory descriptors
3261 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3263 * Returns a freshly-opened close-on-exec file descriptor for the library,
3264 * or -1 if the library cannot be found.
3267 search_library_pathfds(const char *name, const char *path, int *fdp)
3269 char *envcopy, *fdstr, *found, *last_token;
3273 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3275 /* Don't load from user-specified libdirs into setuid binaries. */
3279 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3283 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3284 if (name[0] == '/') {
3285 dbg("Absolute path (%s) passed to %s", name, __func__);
3290 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3291 * copy of the path, as strtok_r rewrites separator tokens
3295 envcopy = xstrdup(path);
3296 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3297 fdstr = strtok_r(NULL, ":", &last_token)) {
3298 dirfd = parse_integer(fdstr);
3300 _rtld_error("failed to parse directory FD: '%s'",
3304 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3307 len = strlen(fdstr) + strlen(name) + 3;
3308 found = xmalloc(len);
3309 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
3310 _rtld_error("error generating '%d/%s'",
3314 dbg("open('%s') => %d", found, fd);
3325 dlclose(void *handle)
3327 RtldLockState lockstate;
3330 wlock_acquire(rtld_bind_lock, &lockstate);
3331 error = dlclose_locked(handle, &lockstate);
3332 lock_release(rtld_bind_lock, &lockstate);
3337 dlclose_locked(void *handle, RtldLockState *lockstate)
3341 root = dlcheck(handle);
3344 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3347 /* Unreference the object and its dependencies. */
3348 root->dl_refcount--;
3350 if (root->refcount == 1) {
3352 * The object will be no longer referenced, so we must unload it.
3353 * First, call the fini functions.
3355 objlist_call_fini(&list_fini, root, lockstate);
3359 /* Finish cleaning up the newly-unreferenced objects. */
3360 GDB_STATE(RT_DELETE,&root->linkmap);
3361 unload_object(root, lockstate);
3362 GDB_STATE(RT_CONSISTENT,NULL);
3366 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3373 char *msg = error_message;
3374 error_message = NULL;
3379 * This function is deprecated and has no effect.
3382 dllockinit(void *context,
3383 void *(*_lock_create)(void *context) __unused,
3384 void (*_rlock_acquire)(void *lock) __unused,
3385 void (*_wlock_acquire)(void *lock) __unused,
3386 void (*_lock_release)(void *lock) __unused,
3387 void (*_lock_destroy)(void *lock) __unused,
3388 void (*context_destroy)(void *context))
3390 static void *cur_context;
3391 static void (*cur_context_destroy)(void *);
3393 /* Just destroy the context from the previous call, if necessary. */
3394 if (cur_context_destroy != NULL)
3395 cur_context_destroy(cur_context);
3396 cur_context = context;
3397 cur_context_destroy = context_destroy;
3401 dlopen(const char *name, int mode)
3404 return (rtld_dlopen(name, -1, mode));
3408 fdlopen(int fd, int mode)
3411 return (rtld_dlopen(NULL, fd, mode));
3415 rtld_dlopen(const char *name, int fd, int mode)
3417 RtldLockState lockstate;
3420 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3421 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3422 if (ld_tracing != NULL) {
3423 rlock_acquire(rtld_bind_lock, &lockstate);
3424 if (sigsetjmp(lockstate.env, 0) != 0)
3425 lock_upgrade(rtld_bind_lock, &lockstate);
3426 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate));
3427 lock_release(rtld_bind_lock, &lockstate);
3429 lo_flags = RTLD_LO_DLOPEN;
3430 if (mode & RTLD_NODELETE)
3431 lo_flags |= RTLD_LO_NODELETE;
3432 if (mode & RTLD_NOLOAD)
3433 lo_flags |= RTLD_LO_NOLOAD;
3434 if (mode & RTLD_DEEPBIND)
3435 lo_flags |= RTLD_LO_DEEPBIND;
3436 if (ld_tracing != NULL)
3437 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS;
3439 return (dlopen_object(name, fd, obj_main, lo_flags,
3440 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3444 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3449 if (obj->refcount == 0)
3450 unload_object(obj, lockstate);
3454 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3455 int mode, RtldLockState *lockstate)
3457 Obj_Entry *old_obj_tail;
3460 RtldLockState mlockstate;
3463 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x",
3464 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" :
3465 refobj->path, lo_flags, mode);
3466 objlist_init(&initlist);
3468 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3469 wlock_acquire(rtld_bind_lock, &mlockstate);
3470 lockstate = &mlockstate;
3472 GDB_STATE(RT_ADD,NULL);
3474 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
3476 if (name == NULL && fd == -1) {
3480 obj = load_object(name, fd, refobj, lo_flags);
3485 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3486 objlist_push_tail(&list_global, obj);
3487 if (globallist_next(old_obj_tail) != NULL) {
3488 /* We loaded something new. */
3489 assert(globallist_next(old_obj_tail) == obj);
3490 if ((lo_flags & RTLD_LO_DEEPBIND) != 0)
3491 obj->symbolic = true;
3493 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 &&
3494 obj->static_tls && !allocate_tls_offset(obj)) {
3495 _rtld_error("%s: No space available "
3496 "for static Thread Local Storage", obj->path);
3500 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN |
3501 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE));
3505 result = rtld_verify_versions(&obj->dagmembers);
3506 if (result != -1 && ld_tracing)
3508 if (result == -1 || relocate_object_dag(obj,
3509 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3510 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3512 dlopen_cleanup(obj, lockstate);
3514 } else if (lo_flags & RTLD_LO_EARLY) {
3516 * Do not call the init functions for early loaded
3517 * filtees. The image is still not initialized enough
3520 * Our object is found by the global object list and
3521 * will be ordered among all init calls done right
3522 * before transferring control to main.
3525 /* Make list of init functions to call. */
3526 initlist_add_objects(obj, obj, &initlist);
3529 * Process all no_delete or global objects here, given
3530 * them own DAGs to prevent their dependencies from being
3531 * unloaded. This has to be done after we have loaded all
3532 * of the dependencies, so that we do not miss any.
3538 * Bump the reference counts for objects on this DAG. If
3539 * this is the first dlopen() call for the object that was
3540 * already loaded as a dependency, initialize the dag
3546 if ((lo_flags & RTLD_LO_TRACE) != 0)
3549 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3550 obj->z_nodelete) && !obj->ref_nodel) {
3551 dbg("obj %s nodelete", obj->path);
3553 obj->z_nodelete = obj->ref_nodel = true;
3557 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3559 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3561 if ((lo_flags & RTLD_LO_EARLY) == 0) {
3562 map_stacks_exec(lockstate);
3564 distribute_static_tls(&initlist, lockstate);
3567 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3568 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3570 objlist_clear(&initlist);
3571 dlopen_cleanup(obj, lockstate);
3572 if (lockstate == &mlockstate)
3573 lock_release(rtld_bind_lock, lockstate);
3577 if (!(lo_flags & RTLD_LO_EARLY)) {
3578 /* Call the init functions. */
3579 objlist_call_init(&initlist, lockstate);
3581 objlist_clear(&initlist);
3582 if (lockstate == &mlockstate)
3583 lock_release(rtld_bind_lock, lockstate);
3586 trace_loaded_objects(obj);
3587 if (lockstate == &mlockstate)
3588 lock_release(rtld_bind_lock, lockstate);
3593 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3597 const Obj_Entry *obj, *defobj;
3600 RtldLockState lockstate;
3607 symlook_init(&req, name);
3609 req.flags = flags | SYMLOOK_IN_PLT;
3610 req.lockstate = &lockstate;
3612 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3613 rlock_acquire(rtld_bind_lock, &lockstate);
3614 if (sigsetjmp(lockstate.env, 0) != 0)
3615 lock_upgrade(rtld_bind_lock, &lockstate);
3616 if (handle == NULL || handle == RTLD_NEXT ||
3617 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3619 if ((obj = obj_from_addr(retaddr)) == NULL) {
3620 _rtld_error("Cannot determine caller's shared object");
3621 lock_release(rtld_bind_lock, &lockstate);
3622 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3625 if (handle == NULL) { /* Just the caller's shared object. */
3626 res = symlook_obj(&req, obj);
3629 defobj = req.defobj_out;
3631 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3632 handle == RTLD_SELF) { /* ... caller included */
3633 if (handle == RTLD_NEXT)
3634 obj = globallist_next(obj);
3635 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3638 res = symlook_obj(&req, obj);
3641 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3643 defobj = req.defobj_out;
3644 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3650 * Search the dynamic linker itself, and possibly resolve the
3651 * symbol from there. This is how the application links to
3652 * dynamic linker services such as dlopen.
3654 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3655 res = symlook_obj(&req, &obj_rtld);
3658 defobj = req.defobj_out;
3662 assert(handle == RTLD_DEFAULT);
3663 res = symlook_default(&req, obj);
3665 defobj = req.defobj_out;
3670 if ((obj = dlcheck(handle)) == NULL) {
3671 lock_release(rtld_bind_lock, &lockstate);
3672 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3676 donelist_init(&donelist);
3677 if (obj->mainprog) {
3678 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3679 res = symlook_global(&req, &donelist);
3682 defobj = req.defobj_out;
3685 * Search the dynamic linker itself, and possibly resolve the
3686 * symbol from there. This is how the application links to
3687 * dynamic linker services such as dlopen.
3689 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3690 res = symlook_obj(&req, &obj_rtld);
3693 defobj = req.defobj_out;
3698 /* Search the whole DAG rooted at the given object. */
3699 res = symlook_list(&req, &obj->dagmembers, &donelist);
3702 defobj = req.defobj_out;
3708 lock_release(rtld_bind_lock, &lockstate);
3711 * The value required by the caller is derived from the value
3712 * of the symbol. this is simply the relocated value of the
3715 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3716 sym = make_function_pointer(def, defobj);
3717 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3718 sym = rtld_resolve_ifunc(defobj, def);
3719 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3720 ti.ti_module = defobj->tlsindex;
3721 ti.ti_offset = def->st_value;
3722 sym = __tls_get_addr(&ti);
3724 sym = defobj->relocbase + def->st_value;
3725 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3729 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
3730 ve != NULL ? ve->name : "");
3731 lock_release(rtld_bind_lock, &lockstate);
3732 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3737 dlsym(void *handle, const char *name)
3739 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3744 dlfunc(void *handle, const char *name)
3751 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3757 dlvsym(void *handle, const char *name, const char *version)
3761 ventry.name = version;
3763 ventry.hash = elf_hash(version);
3765 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3770 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3772 const Obj_Entry *obj;
3773 RtldLockState lockstate;
3775 rlock_acquire(rtld_bind_lock, &lockstate);
3776 obj = obj_from_addr(addr);
3778 _rtld_error("No shared object contains address");
3779 lock_release(rtld_bind_lock, &lockstate);
3782 rtld_fill_dl_phdr_info(obj, phdr_info);
3783 lock_release(rtld_bind_lock, &lockstate);
3788 dladdr(const void *addr, Dl_info *info)
3790 const Obj_Entry *obj;
3793 unsigned long symoffset;
3794 RtldLockState lockstate;
3796 rlock_acquire(rtld_bind_lock, &lockstate);
3797 obj = obj_from_addr(addr);
3799 _rtld_error("No shared object contains address");
3800 lock_release(rtld_bind_lock, &lockstate);
3803 info->dli_fname = obj->path;
3804 info->dli_fbase = obj->mapbase;
3805 info->dli_saddr = (void *)0;
3806 info->dli_sname = NULL;
3809 * Walk the symbol list looking for the symbol whose address is
3810 * closest to the address sent in.
3812 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3813 def = obj->symtab + symoffset;
3816 * For skip the symbol if st_shndx is either SHN_UNDEF or
3819 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3823 * If the symbol is greater than the specified address, or if it
3824 * is further away from addr than the current nearest symbol,
3827 symbol_addr = obj->relocbase + def->st_value;
3828 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3831 /* Update our idea of the nearest symbol. */
3832 info->dli_sname = obj->strtab + def->st_name;
3833 info->dli_saddr = symbol_addr;
3836 if (info->dli_saddr == addr)
3839 lock_release(rtld_bind_lock, &lockstate);
3844 dlinfo(void *handle, int request, void *p)
3846 const Obj_Entry *obj;
3847 RtldLockState lockstate;
3850 rlock_acquire(rtld_bind_lock, &lockstate);
3852 if (handle == NULL || handle == RTLD_SELF) {
3855 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3856 if ((obj = obj_from_addr(retaddr)) == NULL)
3857 _rtld_error("Cannot determine caller's shared object");
3859 obj = dlcheck(handle);
3862 lock_release(rtld_bind_lock, &lockstate);
3868 case RTLD_DI_LINKMAP:
3869 *((struct link_map const **)p) = &obj->linkmap;
3871 case RTLD_DI_ORIGIN:
3872 error = rtld_dirname(obj->path, p);
3875 case RTLD_DI_SERINFOSIZE:
3876 case RTLD_DI_SERINFO:
3877 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3881 _rtld_error("Invalid request %d passed to dlinfo()", request);
3885 lock_release(rtld_bind_lock, &lockstate);
3891 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3894 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3895 phdr_info->dlpi_name = obj->path;
3896 phdr_info->dlpi_phdr = obj->phdr;
3897 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3898 phdr_info->dlpi_tls_modid = obj->tlsindex;
3899 phdr_info->dlpi_tls_data = obj->tlsinit;
3900 phdr_info->dlpi_adds = obj_loads;
3901 phdr_info->dlpi_subs = obj_loads - obj_count;
3905 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3907 struct dl_phdr_info phdr_info;
3908 Obj_Entry *obj, marker;
3909 RtldLockState bind_lockstate, phdr_lockstate;
3912 init_marker(&marker);
3915 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3916 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3917 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
3918 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
3919 rtld_fill_dl_phdr_info(obj, &phdr_info);
3921 lock_release(rtld_bind_lock, &bind_lockstate);
3923 error = callback(&phdr_info, sizeof phdr_info, param);
3925 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3927 obj = globallist_next(&marker);
3928 TAILQ_REMOVE(&obj_list, &marker, next);
3930 lock_release(rtld_bind_lock, &bind_lockstate);
3931 lock_release(rtld_phdr_lock, &phdr_lockstate);
3937 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3938 lock_release(rtld_bind_lock, &bind_lockstate);
3939 error = callback(&phdr_info, sizeof(phdr_info), param);
3941 lock_release(rtld_phdr_lock, &phdr_lockstate);
3946 fill_search_info(const char *dir, size_t dirlen, void *param)
3948 struct fill_search_info_args *arg;
3952 if (arg->request == RTLD_DI_SERINFOSIZE) {
3953 arg->serinfo->dls_cnt ++;
3954 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3956 struct dl_serpath *s_entry;
3958 s_entry = arg->serpath;
3959 s_entry->dls_name = arg->strspace;
3960 s_entry->dls_flags = arg->flags;
3962 strncpy(arg->strspace, dir, dirlen);
3963 arg->strspace[dirlen] = '\0';
3965 arg->strspace += dirlen + 1;
3973 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3975 struct dl_serinfo _info;
3976 struct fill_search_info_args args;
3978 args.request = RTLD_DI_SERINFOSIZE;
3979 args.serinfo = &_info;
3981 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3984 path_enumerate(obj->rpath, fill_search_info, NULL, &args);
3985 path_enumerate(ld_library_path, fill_search_info, NULL, &args);
3986 path_enumerate(obj->runpath, fill_search_info, NULL, &args);
3987 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args);
3988 if (!obj->z_nodeflib)
3989 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args);
3992 if (request == RTLD_DI_SERINFOSIZE) {
3993 info->dls_size = _info.dls_size;
3994 info->dls_cnt = _info.dls_cnt;
3998 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3999 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
4003 args.request = RTLD_DI_SERINFO;
4004 args.serinfo = info;
4005 args.serpath = &info->dls_serpath[0];
4006 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
4008 args.flags = LA_SER_RUNPATH;
4009 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL)
4012 args.flags = LA_SER_LIBPATH;
4013 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL)
4016 args.flags = LA_SER_RUNPATH;
4017 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL)
4020 args.flags = LA_SER_CONFIG;
4021 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args)
4025 args.flags = LA_SER_DEFAULT;
4026 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path,
4027 fill_search_info, NULL, &args) != NULL)
4033 rtld_dirname(const char *path, char *bname)
4037 /* Empty or NULL string gets treated as "." */
4038 if (path == NULL || *path == '\0') {
4044 /* Strip trailing slashes */
4045 endp = path + strlen(path) - 1;
4046 while (endp > path && *endp == '/')
4049 /* Find the start of the dir */
4050 while (endp > path && *endp != '/')
4053 /* Either the dir is "/" or there are no slashes */
4055 bname[0] = *endp == '/' ? '/' : '.';
4061 } while (endp > path && *endp == '/');
4064 if (endp - path + 2 > PATH_MAX)
4066 _rtld_error("Filename is too long: %s", path);
4070 strncpy(bname, path, endp - path + 1);
4071 bname[endp - path + 1] = '\0';
4076 rtld_dirname_abs(const char *path, char *base)
4080 if (realpath(path, base) == NULL) {
4081 _rtld_error("realpath \"%s\" failed (%s)", path,
4082 rtld_strerror(errno));
4085 dbg("%s -> %s", path, base);
4086 last = strrchr(base, '/');
4088 _rtld_error("non-abs result from realpath \"%s\"", path);
4097 linkmap_add(Obj_Entry *obj)
4099 struct link_map *l, *prev;
4102 l->l_name = obj->path;
4103 l->l_base = obj->mapbase;
4104 l->l_ld = obj->dynamic;
4105 l->l_addr = obj->relocbase;
4107 if (r_debug.r_map == NULL) {
4113 * Scan to the end of the list, but not past the entry for the
4114 * dynamic linker, which we want to keep at the very end.
4116 for (prev = r_debug.r_map;
4117 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
4118 prev = prev->l_next)
4121 /* Link in the new entry. */
4123 l->l_next = prev->l_next;
4124 if (l->l_next != NULL)
4125 l->l_next->l_prev = l;
4130 linkmap_delete(Obj_Entry *obj)
4135 if (l->l_prev == NULL) {
4136 if ((r_debug.r_map = l->l_next) != NULL)
4137 l->l_next->l_prev = NULL;
4141 if ((l->l_prev->l_next = l->l_next) != NULL)
4142 l->l_next->l_prev = l->l_prev;
4146 * Function for the debugger to set a breakpoint on to gain control.
4148 * The two parameters allow the debugger to easily find and determine
4149 * what the runtime loader is doing and to whom it is doing it.
4151 * When the loadhook trap is hit (r_debug_state, set at program
4152 * initialization), the arguments can be found on the stack:
4154 * +8 struct link_map *m
4155 * +4 struct r_debug *rd
4159 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused)
4162 * The following is a hack to force the compiler to emit calls to
4163 * this function, even when optimizing. If the function is empty,
4164 * the compiler is not obliged to emit any code for calls to it,
4165 * even when marked __noinline. However, gdb depends on those
4168 __compiler_membar();
4172 * A function called after init routines have completed. This can be used to
4173 * break before a program's entry routine is called, and can be used when
4174 * main is not available in the symbol table.
4177 _r_debug_postinit(struct link_map *m __unused)
4180 /* See r_debug_state(). */
4181 __compiler_membar();
4185 release_object(Obj_Entry *obj)
4188 if (obj->holdcount > 0) {
4189 obj->unholdfree = true;
4192 munmap(obj->mapbase, obj->mapsize);
4193 linkmap_delete(obj);
4198 * Get address of the pointer variable in the main program.
4199 * Prefer non-weak symbol over the weak one.
4201 static const void **
4202 get_program_var_addr(const char *name, RtldLockState *lockstate)
4207 symlook_init(&req, name);
4208 req.lockstate = lockstate;
4209 donelist_init(&donelist);
4210 if (symlook_global(&req, &donelist) != 0)
4212 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4213 return ((const void **)make_function_pointer(req.sym_out,
4215 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4216 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
4218 return ((const void **)(req.defobj_out->relocbase +
4219 req.sym_out->st_value));
4223 * Set a pointer variable in the main program to the given value. This
4224 * is used to set key variables such as "environ" before any of the
4225 * init functions are called.
4228 set_program_var(const char *name, const void *value)
4232 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4233 dbg("\"%s\": *%p <-- %p", name, addr, value);
4239 * Search the global objects, including dependencies and main object,
4240 * for the given symbol.
4243 symlook_global(SymLook *req, DoneList *donelist)
4246 const Objlist_Entry *elm;
4249 symlook_init_from_req(&req1, req);
4251 /* Search all objects loaded at program start up. */
4252 if (req->defobj_out == NULL ||
4253 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4254 res = symlook_list(&req1, &list_main, donelist);
4255 if (res == 0 && (req->defobj_out == NULL ||
4256 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4257 req->sym_out = req1.sym_out;
4258 req->defobj_out = req1.defobj_out;
4259 assert(req->defobj_out != NULL);
4263 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4264 STAILQ_FOREACH(elm, &list_global, link) {
4265 if (req->defobj_out != NULL &&
4266 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4268 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4269 if (res == 0 && (req->defobj_out == NULL ||
4270 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4271 req->sym_out = req1.sym_out;
4272 req->defobj_out = req1.defobj_out;
4273 assert(req->defobj_out != NULL);
4277 return (req->sym_out != NULL ? 0 : ESRCH);
4281 * Given a symbol name in a referencing object, find the corresponding
4282 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4283 * no definition was found. Returns a pointer to the Obj_Entry of the
4284 * defining object via the reference parameter DEFOBJ_OUT.
4287 symlook_default(SymLook *req, const Obj_Entry *refobj)
4290 const Objlist_Entry *elm;
4294 donelist_init(&donelist);
4295 symlook_init_from_req(&req1, req);
4298 * Look first in the referencing object if linked symbolically,
4299 * and similarly handle protected symbols.
4301 res = symlook_obj(&req1, refobj);
4302 if (res == 0 && (refobj->symbolic ||
4303 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) {
4304 req->sym_out = req1.sym_out;
4305 req->defobj_out = req1.defobj_out;
4306 assert(req->defobj_out != NULL);
4308 if (refobj->symbolic || req->defobj_out != NULL)
4309 donelist_check(&donelist, refobj);
4311 symlook_global(req, &donelist);
4313 /* Search all dlopened DAGs containing the referencing object. */
4314 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4315 if (req->sym_out != NULL &&
4316 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4318 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4319 if (res == 0 && (req->sym_out == NULL ||
4320 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4321 req->sym_out = req1.sym_out;
4322 req->defobj_out = req1.defobj_out;
4323 assert(req->defobj_out != NULL);
4328 * Search the dynamic linker itself, and possibly resolve the
4329 * symbol from there. This is how the application links to
4330 * dynamic linker services such as dlopen.
4332 if (req->sym_out == NULL ||
4333 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4334 res = symlook_obj(&req1, &obj_rtld);
4336 req->sym_out = req1.sym_out;
4337 req->defobj_out = req1.defobj_out;
4338 assert(req->defobj_out != NULL);
4342 return (req->sym_out != NULL ? 0 : ESRCH);
4346 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4349 const Obj_Entry *defobj;
4350 const Objlist_Entry *elm;
4356 STAILQ_FOREACH(elm, objlist, link) {
4357 if (donelist_check(dlp, elm->obj))
4359 symlook_init_from_req(&req1, req);
4360 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4361 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4363 defobj = req1.defobj_out;
4364 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4371 req->defobj_out = defobj;
4378 * Search the chain of DAGS cointed to by the given Needed_Entry
4379 * for a symbol of the given name. Each DAG is scanned completely
4380 * before advancing to the next one. Returns a pointer to the symbol,
4381 * or NULL if no definition was found.
4384 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4387 const Needed_Entry *n;
4388 const Obj_Entry *defobj;
4394 symlook_init_from_req(&req1, req);
4395 for (n = needed; n != NULL; n = n->next) {
4396 if (n->obj == NULL ||
4397 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
4399 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4401 defobj = req1.defobj_out;
4402 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4408 req->defobj_out = defobj;
4415 * Search the symbol table of a single shared object for a symbol of
4416 * the given name and version, if requested. Returns a pointer to the
4417 * symbol, or NULL if no definition was found. If the object is
4418 * filter, return filtered symbol from filtee.
4420 * The symbol's hash value is passed in for efficiency reasons; that
4421 * eliminates many recomputations of the hash value.
4424 symlook_obj(SymLook *req, const Obj_Entry *obj)
4428 int flags, res, mres;
4431 * If there is at least one valid hash at this point, we prefer to
4432 * use the faster GNU version if available.
4434 if (obj->valid_hash_gnu)
4435 mres = symlook_obj1_gnu(req, obj);
4436 else if (obj->valid_hash_sysv)
4437 mres = symlook_obj1_sysv(req, obj);
4442 if (obj->needed_filtees != NULL) {
4443 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4444 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4445 donelist_init(&donelist);
4446 symlook_init_from_req(&req1, req);
4447 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
4449 req->sym_out = req1.sym_out;
4450 req->defobj_out = req1.defobj_out;
4454 if (obj->needed_aux_filtees != NULL) {
4455 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4456 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4457 donelist_init(&donelist);
4458 symlook_init_from_req(&req1, req);
4459 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
4461 req->sym_out = req1.sym_out;
4462 req->defobj_out = req1.defobj_out;
4470 /* Symbol match routine common to both hash functions */
4472 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4473 const unsigned long symnum)
4476 const Elf_Sym *symp;
4479 symp = obj->symtab + symnum;
4480 strp = obj->strtab + symp->st_name;
4482 switch (ELF_ST_TYPE(symp->st_info)) {
4488 if (symp->st_value == 0)
4492 if (symp->st_shndx != SHN_UNDEF)
4495 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4496 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4503 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4506 if (req->ventry == NULL) {
4507 if (obj->versyms != NULL) {
4508 verndx = VER_NDX(obj->versyms[symnum]);
4509 if (verndx > obj->vernum) {
4511 "%s: symbol %s references wrong version %d",
4512 obj->path, obj->strtab + symnum, verndx);
4516 * If we are not called from dlsym (i.e. this
4517 * is a normal relocation from unversioned
4518 * binary), accept the symbol immediately if
4519 * it happens to have first version after this
4520 * shared object became versioned. Otherwise,
4521 * if symbol is versioned and not hidden,
4522 * remember it. If it is the only symbol with
4523 * this name exported by the shared object, it
4524 * will be returned as a match by the calling
4525 * function. If symbol is global (verndx < 2)
4526 * accept it unconditionally.
4528 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4529 verndx == VER_NDX_GIVEN) {
4530 result->sym_out = symp;
4533 else if (verndx >= VER_NDX_GIVEN) {
4534 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4536 if (result->vsymp == NULL)
4537 result->vsymp = symp;
4543 result->sym_out = symp;
4546 if (obj->versyms == NULL) {
4547 if (object_match_name(obj, req->ventry->name)) {
4548 _rtld_error("%s: object %s should provide version %s "
4549 "for symbol %s", obj_rtld.path, obj->path,
4550 req->ventry->name, obj->strtab + symnum);
4554 verndx = VER_NDX(obj->versyms[symnum]);
4555 if (verndx > obj->vernum) {
4556 _rtld_error("%s: symbol %s references wrong version %d",
4557 obj->path, obj->strtab + symnum, verndx);
4560 if (obj->vertab[verndx].hash != req->ventry->hash ||
4561 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4563 * Version does not match. Look if this is a
4564 * global symbol and if it is not hidden. If
4565 * global symbol (verndx < 2) is available,
4566 * use it. Do not return symbol if we are
4567 * called by dlvsym, because dlvsym looks for
4568 * a specific version and default one is not
4569 * what dlvsym wants.
4571 if ((req->flags & SYMLOOK_DLSYM) ||
4572 (verndx >= VER_NDX_GIVEN) ||
4573 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4577 result->sym_out = symp;
4582 * Search for symbol using SysV hash function.
4583 * obj->buckets is known not to be NULL at this point; the test for this was
4584 * performed with the obj->valid_hash_sysv assignment.
4587 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4589 unsigned long symnum;
4590 Sym_Match_Result matchres;
4592 matchres.sym_out = NULL;
4593 matchres.vsymp = NULL;
4594 matchres.vcount = 0;
4596 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4597 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4598 if (symnum >= obj->nchains)
4599 return (ESRCH); /* Bad object */
4601 if (matched_symbol(req, obj, &matchres, symnum)) {
4602 req->sym_out = matchres.sym_out;
4603 req->defobj_out = obj;
4607 if (matchres.vcount == 1) {
4608 req->sym_out = matchres.vsymp;
4609 req->defobj_out = obj;
4615 /* Search for symbol using GNU hash function */
4617 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4619 Elf_Addr bloom_word;
4620 const Elf32_Word *hashval;
4622 Sym_Match_Result matchres;
4623 unsigned int h1, h2;
4624 unsigned long symnum;
4626 matchres.sym_out = NULL;
4627 matchres.vsymp = NULL;
4628 matchres.vcount = 0;
4630 /* Pick right bitmask word from Bloom filter array */
4631 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4632 obj->maskwords_bm_gnu];
4634 /* Calculate modulus word size of gnu hash and its derivative */
4635 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4636 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4638 /* Filter out the "definitely not in set" queries */
4639 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4642 /* Locate hash chain and corresponding value element*/
4643 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4646 hashval = &obj->chain_zero_gnu[bucket];
4648 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4649 symnum = hashval - obj->chain_zero_gnu;
4650 if (matched_symbol(req, obj, &matchres, symnum)) {
4651 req->sym_out = matchres.sym_out;
4652 req->defobj_out = obj;
4656 } while ((*hashval++ & 1) == 0);
4657 if (matchres.vcount == 1) {
4658 req->sym_out = matchres.vsymp;
4659 req->defobj_out = obj;
4666 trace_loaded_objects(Obj_Entry *obj)
4668 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4671 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL)
4674 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL)
4675 fmt1 = "\t%o => %p (%x)\n";
4677 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL)
4678 fmt2 = "\t%o (%x)\n";
4680 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL"));
4682 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4683 Needed_Entry *needed;
4684 const char *name, *path;
4689 if (list_containers && obj->needed != NULL)
4690 rtld_printf("%s:\n", obj->path);
4691 for (needed = obj->needed; needed; needed = needed->next) {
4692 if (needed->obj != NULL) {
4693 if (needed->obj->traced && !list_containers)
4695 needed->obj->traced = true;
4696 path = needed->obj->path;
4700 name = obj->strtab + needed->name;
4701 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4703 fmt = is_lib ? fmt1 : fmt2;
4704 while ((c = *fmt++) != '\0') {
4730 rtld_putstr(main_local);
4733 rtld_putstr(obj_main->path);
4740 rtld_printf("%d", sodp->sod_major);
4743 rtld_printf("%d", sodp->sod_minor);
4750 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4763 * Unload a dlopened object and its dependencies from memory and from
4764 * our data structures. It is assumed that the DAG rooted in the
4765 * object has already been unreferenced, and that the object has a
4766 * reference count of 0.
4769 unload_object(Obj_Entry *root, RtldLockState *lockstate)
4771 Obj_Entry marker, *obj, *next;
4773 assert(root->refcount == 0);
4776 * Pass over the DAG removing unreferenced objects from
4777 * appropriate lists.
4779 unlink_object(root);
4781 /* Unmap all objects that are no longer referenced. */
4782 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
4783 next = TAILQ_NEXT(obj, next);
4784 if (obj->marker || obj->refcount != 0)
4786 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
4787 obj->mapsize, 0, obj->path);
4788 dbg("unloading \"%s\"", obj->path);
4790 * Unlink the object now to prevent new references from
4791 * being acquired while the bind lock is dropped in
4792 * recursive dlclose() invocations.
4794 TAILQ_REMOVE(&obj_list, obj, next);
4797 if (obj->filtees_loaded) {
4799 init_marker(&marker);
4800 TAILQ_INSERT_BEFORE(next, &marker, next);
4801 unload_filtees(obj, lockstate);
4802 next = TAILQ_NEXT(&marker, next);
4803 TAILQ_REMOVE(&obj_list, &marker, next);
4805 unload_filtees(obj, lockstate);
4807 release_object(obj);
4812 unlink_object(Obj_Entry *root)
4816 if (root->refcount == 0) {
4817 /* Remove the object from the RTLD_GLOBAL list. */
4818 objlist_remove(&list_global, root);
4820 /* Remove the object from all objects' DAG lists. */
4821 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4822 objlist_remove(&elm->obj->dldags, root);
4823 if (elm->obj != root)
4824 unlink_object(elm->obj);
4830 ref_dag(Obj_Entry *root)
4834 assert(root->dag_inited);
4835 STAILQ_FOREACH(elm, &root->dagmembers, link)
4836 elm->obj->refcount++;
4840 unref_dag(Obj_Entry *root)
4844 assert(root->dag_inited);
4845 STAILQ_FOREACH(elm, &root->dagmembers, link)
4846 elm->obj->refcount--;
4850 * Common code for MD __tls_get_addr().
4852 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4854 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4856 Elf_Addr *newdtv, *dtv;
4857 RtldLockState lockstate;
4861 /* Check dtv generation in case new modules have arrived */
4862 if (dtv[0] != tls_dtv_generation) {
4863 wlock_acquire(rtld_bind_lock, &lockstate);
4864 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4866 if (to_copy > tls_max_index)
4867 to_copy = tls_max_index;
4868 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4869 newdtv[0] = tls_dtv_generation;
4870 newdtv[1] = tls_max_index;
4872 lock_release(rtld_bind_lock, &lockstate);
4873 dtv = *dtvp = newdtv;
4876 /* Dynamically allocate module TLS if necessary */
4877 if (dtv[index + 1] == 0) {
4878 /* Signal safe, wlock will block out signals. */
4879 wlock_acquire(rtld_bind_lock, &lockstate);
4880 if (!dtv[index + 1])
4881 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4882 lock_release(rtld_bind_lock, &lockstate);
4884 return ((void *)(dtv[index + 1] + offset));
4888 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4893 /* Check dtv generation in case new modules have arrived */
4894 if (__predict_true(dtv[0] == tls_dtv_generation &&
4895 dtv[index + 1] != 0))
4896 return ((void *)(dtv[index + 1] + offset));
4897 return (tls_get_addr_slow(dtvp, index, offset));
4900 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
4901 defined(__powerpc__) || defined(__riscv)
4904 * Return pointer to allocated TLS block
4907 get_tls_block_ptr(void *tcb, size_t tcbsize)
4909 size_t extra_size, post_size, pre_size, tls_block_size;
4910 size_t tls_init_align;
4912 tls_init_align = MAX(obj_main->tlsalign, 1);
4914 /* Compute fragments sizes. */
4915 extra_size = tcbsize - TLS_TCB_SIZE;
4916 post_size = calculate_tls_post_size(tls_init_align);
4917 tls_block_size = tcbsize + post_size;
4918 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4920 return ((char *)tcb - pre_size - extra_size);
4924 * Allocate Static TLS using the Variant I method.
4926 * For details on the layout, see lib/libc/gen/tls.c.
4928 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as
4929 * it is based on tls_last_offset, and TLS offsets here are really TCB
4930 * offsets, whereas libc's tls_static_space is just the executable's static
4934 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4938 Elf_Addr *dtv, **tcb;
4941 size_t extra_size, maxalign, post_size, pre_size, tls_block_size;
4942 size_t tls_init_align, tls_init_offset;
4944 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4947 assert(tcbsize >= TLS_TCB_SIZE);
4948 maxalign = MAX(tcbalign, tls_static_max_align);
4949 tls_init_align = MAX(obj_main->tlsalign, 1);
4951 /* Compute fragmets sizes. */
4952 extra_size = tcbsize - TLS_TCB_SIZE;
4953 post_size = calculate_tls_post_size(tls_init_align);
4954 tls_block_size = tcbsize + post_size;
4955 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4956 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size;
4958 /* Allocate whole TLS block */
4959 tls_block = malloc_aligned(tls_block_size, maxalign, 0);
4960 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size);
4962 if (oldtcb != NULL) {
4963 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize),
4965 free_aligned(get_tls_block_ptr(oldtcb, tcbsize));
4967 /* Adjust the DTV. */
4969 for (i = 0; i < dtv[1]; i++) {
4970 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4971 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4972 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb;
4976 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4978 dtv[0] = tls_dtv_generation;
4979 dtv[1] = tls_max_index;
4981 for (obj = globallist_curr(objs); obj != NULL;
4982 obj = globallist_next(obj)) {
4983 if (obj->tlsoffset == 0)
4985 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1);
4986 addr = (Elf_Addr)tcb + obj->tlsoffset;
4987 if (tls_init_offset > 0)
4988 memset((void *)addr, 0, tls_init_offset);
4989 if (obj->tlsinitsize > 0) {
4990 memcpy((void *)(addr + tls_init_offset), obj->tlsinit,
4993 if (obj->tlssize > obj->tlsinitsize) {
4994 memset((void *)(addr + tls_init_offset + obj->tlsinitsize),
4995 0, obj->tlssize - obj->tlsinitsize - tls_init_offset);
4997 dtv[obj->tlsindex + 1] = addr;
5005 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
5008 Elf_Addr tlsstart, tlsend;
5010 size_t dtvsize, i, tls_init_align;
5012 assert(tcbsize >= TLS_TCB_SIZE);
5013 tls_init_align = MAX(obj_main->tlsalign, 1);
5015 /* Compute fragments sizes. */
5016 post_size = calculate_tls_post_size(tls_init_align);
5018 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size;
5019 tlsend = (Elf_Addr)tcb + tls_static_space;
5021 dtv = *(Elf_Addr **)tcb;
5023 for (i = 0; i < dtvsize; i++) {
5024 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
5025 free((void*)dtv[i+2]);
5029 free_aligned(get_tls_block_ptr(tcb, tcbsize));
5034 #if defined(__i386__) || defined(__amd64__)
5037 * Allocate Static TLS using the Variant II method.
5040 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
5043 size_t size, ralign;
5045 Elf_Addr *dtv, *olddtv;
5046 Elf_Addr segbase, oldsegbase, addr;
5050 if (tls_static_max_align > ralign)
5051 ralign = tls_static_max_align;
5052 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign);
5054 assert(tcbsize >= 2*sizeof(Elf_Addr));
5055 tls = malloc_aligned(size, ralign, 0 /* XXX */);
5056 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
5058 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign));
5059 ((Elf_Addr*)segbase)[0] = segbase;
5060 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
5062 dtv[0] = tls_dtv_generation;
5063 dtv[1] = tls_max_index;
5067 * Copy the static TLS block over whole.
5069 oldsegbase = (Elf_Addr) oldtls;
5070 memcpy((void *)(segbase - tls_static_space),
5071 (const void *)(oldsegbase - tls_static_space),
5075 * If any dynamic TLS blocks have been created tls_get_addr(),
5078 olddtv = ((Elf_Addr**)oldsegbase)[1];
5079 for (i = 0; i < olddtv[1]; i++) {
5080 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
5081 dtv[i+2] = olddtv[i+2];
5087 * We assume that this block was the one we created with
5088 * allocate_initial_tls().
5090 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
5092 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
5093 if (obj->marker || obj->tlsoffset == 0)
5095 addr = segbase - obj->tlsoffset;
5096 memset((void*)(addr + obj->tlsinitsize),
5097 0, obj->tlssize - obj->tlsinitsize);
5099 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
5100 obj->static_tls_copied = true;
5102 dtv[obj->tlsindex + 1] = addr;
5106 return (void*) segbase;
5110 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign)
5113 size_t size, ralign;
5115 Elf_Addr tlsstart, tlsend;
5118 * Figure out the size of the initial TLS block so that we can
5119 * find stuff which ___tls_get_addr() allocated dynamically.
5122 if (tls_static_max_align > ralign)
5123 ralign = tls_static_max_align;
5124 size = roundup(tls_static_space, ralign);
5126 dtv = ((Elf_Addr**)tls)[1];
5128 tlsend = (Elf_Addr) tls;
5129 tlsstart = tlsend - size;
5130 for (i = 0; i < dtvsize; i++) {
5131 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
5132 free_aligned((void *)dtv[i + 2]);
5136 free_aligned((void *)tlsstart);
5143 * Allocate TLS block for module with given index.
5146 allocate_module_tls(int index)
5151 TAILQ_FOREACH(obj, &obj_list, next) {
5154 if (obj->tlsindex == index)
5158 _rtld_error("Can't find module with TLS index %d", index);
5162 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset);
5163 memcpy(p, obj->tlsinit, obj->tlsinitsize);
5164 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
5169 allocate_tls_offset(Obj_Entry *obj)
5176 if (obj->tlssize == 0) {
5177 obj->tls_done = true;
5181 if (tls_last_offset == 0)
5182 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign,
5185 off = calculate_tls_offset(tls_last_offset, tls_last_size,
5186 obj->tlssize, obj->tlsalign, obj->tlspoffset);
5189 * If we have already fixed the size of the static TLS block, we
5190 * must stay within that size. When allocating the static TLS, we
5191 * leave a small amount of space spare to be used for dynamically
5192 * loading modules which use static TLS.
5194 if (tls_static_space != 0) {
5195 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
5197 } else if (obj->tlsalign > tls_static_max_align) {
5198 tls_static_max_align = obj->tlsalign;
5201 tls_last_offset = obj->tlsoffset = off;
5202 tls_last_size = obj->tlssize;
5203 obj->tls_done = true;
5209 free_tls_offset(Obj_Entry *obj)
5213 * If we were the last thing to allocate out of the static TLS
5214 * block, we give our space back to the 'allocator'. This is a
5215 * simplistic workaround to allow libGL.so.1 to be loaded and
5216 * unloaded multiple times.
5218 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
5219 == calculate_tls_end(tls_last_offset, tls_last_size)) {
5220 tls_last_offset -= obj->tlssize;
5226 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
5229 RtldLockState lockstate;
5231 wlock_acquire(rtld_bind_lock, &lockstate);
5232 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
5234 lock_release(rtld_bind_lock, &lockstate);
5239 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
5241 RtldLockState lockstate;
5243 wlock_acquire(rtld_bind_lock, &lockstate);
5244 free_tls(tcb, tcbsize, tcbalign);
5245 lock_release(rtld_bind_lock, &lockstate);
5249 object_add_name(Obj_Entry *obj, const char *name)
5255 entry = malloc(sizeof(Name_Entry) + len);
5257 if (entry != NULL) {
5258 strcpy(entry->name, name);
5259 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5264 object_match_name(const Obj_Entry *obj, const char *name)
5268 STAILQ_FOREACH(entry, &obj->names, link) {
5269 if (strcmp(name, entry->name) == 0)
5276 locate_dependency(const Obj_Entry *obj, const char *name)
5278 const Objlist_Entry *entry;
5279 const Needed_Entry *needed;
5281 STAILQ_FOREACH(entry, &list_main, link) {
5282 if (object_match_name(entry->obj, name))
5286 for (needed = obj->needed; needed != NULL; needed = needed->next) {
5287 if (strcmp(obj->strtab + needed->name, name) == 0 ||
5288 (needed->obj != NULL && object_match_name(needed->obj, name))) {
5290 * If there is DT_NEEDED for the name we are looking for,
5291 * we are all set. Note that object might not be found if
5292 * dependency was not loaded yet, so the function can
5293 * return NULL here. This is expected and handled
5294 * properly by the caller.
5296 return (needed->obj);
5299 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
5305 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
5306 const Elf_Vernaux *vna)
5308 const Elf_Verdef *vd;
5309 const char *vername;
5311 vername = refobj->strtab + vna->vna_name;
5312 vd = depobj->verdef;
5314 _rtld_error("%s: version %s required by %s not defined",
5315 depobj->path, vername, refobj->path);
5319 if (vd->vd_version != VER_DEF_CURRENT) {
5320 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5321 depobj->path, vd->vd_version);
5324 if (vna->vna_hash == vd->vd_hash) {
5325 const Elf_Verdaux *aux = (const Elf_Verdaux *)
5326 ((const char *)vd + vd->vd_aux);
5327 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
5330 if (vd->vd_next == 0)
5332 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5334 if (vna->vna_flags & VER_FLG_WEAK)
5336 _rtld_error("%s: version %s required by %s not found",
5337 depobj->path, vername, refobj->path);
5342 rtld_verify_object_versions(Obj_Entry *obj)
5344 const Elf_Verneed *vn;
5345 const Elf_Verdef *vd;
5346 const Elf_Verdaux *vda;
5347 const Elf_Vernaux *vna;
5348 const Obj_Entry *depobj;
5349 int maxvernum, vernum;
5351 if (obj->ver_checked)
5353 obj->ver_checked = true;
5357 * Walk over defined and required version records and figure out
5358 * max index used by any of them. Do very basic sanity checking
5362 while (vn != NULL) {
5363 if (vn->vn_version != VER_NEED_CURRENT) {
5364 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
5365 obj->path, vn->vn_version);
5368 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5370 vernum = VER_NEED_IDX(vna->vna_other);
5371 if (vernum > maxvernum)
5373 if (vna->vna_next == 0)
5375 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5377 if (vn->vn_next == 0)
5379 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5383 while (vd != NULL) {
5384 if (vd->vd_version != VER_DEF_CURRENT) {
5385 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5386 obj->path, vd->vd_version);
5389 vernum = VER_DEF_IDX(vd->vd_ndx);
5390 if (vernum > maxvernum)
5392 if (vd->vd_next == 0)
5394 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5401 * Store version information in array indexable by version index.
5402 * Verify that object version requirements are satisfied along the
5405 obj->vernum = maxvernum + 1;
5406 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
5409 while (vd != NULL) {
5410 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
5411 vernum = VER_DEF_IDX(vd->vd_ndx);
5412 assert(vernum <= maxvernum);
5413 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux);
5414 obj->vertab[vernum].hash = vd->vd_hash;
5415 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
5416 obj->vertab[vernum].file = NULL;
5417 obj->vertab[vernum].flags = 0;
5419 if (vd->vd_next == 0)
5421 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5425 while (vn != NULL) {
5426 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
5429 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5431 if (check_object_provided_version(obj, depobj, vna))
5433 vernum = VER_NEED_IDX(vna->vna_other);
5434 assert(vernum <= maxvernum);
5435 obj->vertab[vernum].hash = vna->vna_hash;
5436 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
5437 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
5438 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
5439 VER_INFO_HIDDEN : 0;
5440 if (vna->vna_next == 0)
5442 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5444 if (vn->vn_next == 0)
5446 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5452 rtld_verify_versions(const Objlist *objlist)
5454 Objlist_Entry *entry;
5458 STAILQ_FOREACH(entry, objlist, link) {
5460 * Skip dummy objects or objects that have their version requirements
5463 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
5465 if (rtld_verify_object_versions(entry->obj) == -1) {
5467 if (ld_tracing == NULL)
5471 if (rc == 0 || ld_tracing != NULL)
5472 rc = rtld_verify_object_versions(&obj_rtld);
5477 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
5482 vernum = VER_NDX(obj->versyms[symnum]);
5483 if (vernum >= obj->vernum) {
5484 _rtld_error("%s: symbol %s has wrong verneed value %d",
5485 obj->path, obj->strtab + symnum, vernum);
5486 } else if (obj->vertab[vernum].hash != 0) {
5487 return &obj->vertab[vernum];
5494 _rtld_get_stack_prot(void)
5497 return (stack_prot);
5501 _rtld_is_dlopened(void *arg)
5504 RtldLockState lockstate;
5507 rlock_acquire(rtld_bind_lock, &lockstate);
5510 obj = obj_from_addr(arg);
5512 _rtld_error("No shared object contains address");
5513 lock_release(rtld_bind_lock, &lockstate);
5516 res = obj->dlopened ? 1 : 0;
5517 lock_release(rtld_bind_lock, &lockstate);
5522 obj_remap_relro(Obj_Entry *obj, int prot)
5525 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size,
5527 _rtld_error("%s: Cannot set relro protection to %#x: %s",
5528 obj->path, prot, rtld_strerror(errno));
5535 obj_disable_relro(Obj_Entry *obj)
5538 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE));
5542 obj_enforce_relro(Obj_Entry *obj)
5545 return (obj_remap_relro(obj, PROT_READ));
5549 map_stacks_exec(RtldLockState *lockstate)
5551 void (*thr_map_stacks_exec)(void);
5553 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
5555 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
5556 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
5557 if (thr_map_stacks_exec != NULL) {
5558 stack_prot |= PROT_EXEC;
5559 thr_map_stacks_exec();
5564 distribute_static_tls(Objlist *list, RtldLockState *lockstate)
5568 void (*distrib)(size_t, void *, size_t, size_t);
5570 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t)
5571 get_program_var_addr("__pthread_distribute_static_tls", lockstate);
5572 if (distrib == NULL)
5574 STAILQ_FOREACH(elm, list, link) {
5576 if (obj->marker || !obj->tls_done || obj->static_tls_copied)
5578 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize,
5580 obj->static_tls_copied = true;
5585 symlook_init(SymLook *dst, const char *name)
5588 bzero(dst, sizeof(*dst));
5590 dst->hash = elf_hash(name);
5591 dst->hash_gnu = gnu_hash(name);
5595 symlook_init_from_req(SymLook *dst, const SymLook *src)
5598 dst->name = src->name;
5599 dst->hash = src->hash;
5600 dst->hash_gnu = src->hash_gnu;
5601 dst->ventry = src->ventry;
5602 dst->flags = src->flags;
5603 dst->defobj_out = NULL;
5604 dst->sym_out = NULL;
5605 dst->lockstate = src->lockstate;
5609 open_binary_fd(const char *argv0, bool search_in_path,
5610 const char **binpath_res)
5612 char *binpath, *pathenv, *pe, *res1;
5618 if (search_in_path && strchr(argv0, '/') == NULL) {
5619 binpath = xmalloc(PATH_MAX);
5620 pathenv = getenv("PATH");
5621 if (pathenv == NULL) {
5622 _rtld_error("-p and no PATH environment variable");
5625 pathenv = strdup(pathenv);
5626 if (pathenv == NULL) {
5627 _rtld_error("Cannot allocate memory");
5632 while ((pe = strsep(&pathenv, ":")) != NULL) {
5633 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX)
5635 if (binpath[0] != '\0' &&
5636 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX)
5638 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX)
5640 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
5641 if (fd != -1 || errno != ENOENT) {
5648 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
5653 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno));
5656 if (res != NULL && res[0] != '/') {
5657 res1 = xmalloc(PATH_MAX);
5658 if (realpath(res, res1) != NULL) {
5660 free(__DECONST(char *, res));
5671 * Parse a set of command-line arguments.
5674 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp,
5680 int arglen, fd, i, j, mib[2];
5682 bool seen_b, seen_f;
5684 dbg("Parsing command-line arguments");
5687 seen_b = seen_f = false;
5689 for (i = 1; i < argc; i++ ) {
5691 dbg("argv[%d]: '%s'", i, arg);
5694 * rtld arguments end with an explicit "--" or with the first
5695 * non-prefixed argument.
5697 if (strcmp(arg, "--") == 0) {
5705 * All other arguments are single-character options that can
5706 * be combined, so we need to search through `arg` for them.
5708 arglen = strlen(arg);
5709 for (j = 1; j < arglen; j++) {
5712 print_usage(argv[0]);
5714 } else if (opt == 'b') {
5716 _rtld_error("Both -b and -f specified");
5723 } else if (opt == 'f') {
5725 _rtld_error("Both -b and -f specified");
5730 * -f XX can be used to specify a
5731 * descriptor for the binary named at
5732 * the command line (i.e., the later
5733 * argument will specify the process
5734 * name but the descriptor is what
5735 * will actually be executed).
5737 * -f must be the last option in, e.g., -abcf.
5739 if (j != arglen - 1) {
5740 _rtld_error("Invalid options: %s", arg);
5744 fd = parse_integer(argv[i]);
5747 "Invalid file descriptor: '%s'",
5754 } else if (opt == 'p') {
5756 } else if (opt == 'v') {
5759 mib[1] = HW_MACHINE;
5760 sz = sizeof(machine);
5761 sysctl(mib, nitems(mib), machine, &sz, NULL, 0);
5763 "FreeBSD ld-elf.so.1 %s\n"
5764 "FreeBSD_version %d\n"
5765 "Default lib path %s\n"
5770 __FreeBSD_version, ld_standard_library_path,
5771 ld_env_prefix, ld_elf_hints_default,
5772 ld_path_libmap_conf);
5775 _rtld_error("Invalid argument: '%s'", arg);
5776 print_usage(argv[0]);
5788 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
5791 parse_integer(const char *str)
5793 static const int RADIX = 10; /* XXXJA: possibly support hex? */
5800 for (c = *str; c != '\0'; c = *++str) {
5801 if (c < '0' || c > '9')
5808 /* Make sure we actually parsed something. */
5815 print_usage(const char *argv0)
5819 "Usage: %s [-h] [-b <exe>] [-f <FD>] [-p] [--] <binary> [<args>]\n"
5822 " -h Display this help message\n"
5823 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n"
5824 " -f <FD> Execute <FD> instead of searching for <binary>\n"
5825 " -p Search in PATH for named binary\n"
5826 " -v Display identification information\n"
5827 " -- End of RTLD options\n"
5828 " <binary> Name of process to execute\n"
5829 " <args> Arguments to the executed process\n", argv0);
5833 * Overrides for libc_pic-provided functions.
5837 __getosreldate(void)
5847 oid[1] = KERN_OSRELDATE;
5849 len = sizeof(osrel);
5850 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5851 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5856 rtld_strerror(int errnum)
5859 if (errnum < 0 || errnum >= sys_nerr)
5860 return ("Unknown error");
5861 return (sys_errlist[errnum]);
5866 malloc(size_t nbytes)
5869 return (__crt_malloc(nbytes));
5873 calloc(size_t num, size_t size)
5876 return (__crt_calloc(num, size));
5887 realloc(void *cp, size_t nbytes)
5890 return (__crt_realloc(cp, nbytes));
5893 extern int _rtld_version__FreeBSD_version __exported;
5894 int _rtld_version__FreeBSD_version = __FreeBSD_version;
5896 extern char _rtld_version_laddr_offset __exported;
5897 char _rtld_version_laddr_offset;