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",
474 * Set osrel for us, it is later reset to the binary'
475 * value before first instruction of code from the binary
480 mib[2] = KERN_PROC_OSREL;
482 osrel = __FreeBSD_version;
483 sz = sizeof(old_osrel);
484 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel));
486 dbg("opening main program in direct exec mode");
488 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, &argv0);
489 explicit_fd = (fd != -1);
492 fd = open_binary_fd(argv0, search_in_path, &binpath);
493 if (fstat(fd, &st) == -1) {
494 _rtld_error("Failed to fstat FD %d (%s): %s", fd,
495 explicit_fd ? "user-provided descriptor" : argv0,
496 rtld_strerror(errno));
501 * Rough emulation of the permission checks done by
502 * execve(2), only Unix DACs are checked, ACLs are
503 * ignored. Preserve the semantic of disabling owner
504 * to execute if owner x bit is cleared, even if
505 * others x bit is enabled.
506 * mmap(2) does not allow to mmap with PROT_EXEC if
507 * binary' file comes from noexec mount. We cannot
508 * set a text reference on the binary.
511 if (st.st_uid == geteuid()) {
512 if ((st.st_mode & S_IXUSR) != 0)
514 } else if (st.st_gid == getegid()) {
515 if ((st.st_mode & S_IXGRP) != 0)
517 } else if ((st.st_mode & S_IXOTH) != 0) {
521 _rtld_error("No execute permission for binary %s",
527 * For direct exec mode, argv[0] is the interpreter
528 * name, we must remove it and shift arguments left
529 * before invoking binary main. Since stack layout
530 * places environment pointers and aux vectors right
531 * after the terminating NULL, we must shift
532 * environment and aux as well.
534 main_argc = argc - rtld_argc;
535 for (i = 0; i <= main_argc; i++)
536 argv[i] = argv[i + rtld_argc];
538 environ = env = envp = argv + main_argc + 1;
539 dbg("move env from %p to %p", envp + rtld_argc, envp);
541 *envp = *(envp + rtld_argc);
542 } while (*envp++ != NULL);
543 aux = auxp = (Elf_Auxinfo *)envp;
544 auxpf = (Elf_Auxinfo *)(envp + rtld_argc);
545 dbg("move aux from %p to %p", auxpf, aux);
546 /* XXXKIB insert place for AT_EXECPATH if not present */
547 for (;; auxp++, auxpf++) {
549 if (auxp->a_type == AT_NULL)
552 /* Since the auxiliary vector has moved, redigest it. */
553 for (i = 0; i < AT_COUNT; i++)
555 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
556 if (auxp->a_type < AT_COUNT)
557 aux_info[auxp->a_type] = auxp;
560 /* Point AT_EXECPATH auxv and aux_info to the binary path. */
561 if (binpath == NULL) {
562 aux_info[AT_EXECPATH] = NULL;
564 if (aux_info[AT_EXECPATH] == NULL) {
565 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo));
566 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH;
568 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *,
572 _rtld_error("No binary");
578 ld_bind_now = getenv(_LD("BIND_NOW"));
581 * If the process is tainted, then we un-set the dangerous environment
582 * variables. The process will be marked as tainted until setuid(2)
583 * is called. If any child process calls setuid(2) we do not want any
584 * future processes to honor the potentially un-safe variables.
587 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) ||
588 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) ||
589 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) ||
590 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) ||
591 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) {
592 _rtld_error("environment corrupt; aborting");
596 ld_debug = getenv(_LD("DEBUG"));
597 if (ld_bind_now == NULL)
598 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL;
599 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL;
600 libmap_override = getenv(_LD("LIBMAP"));
601 ld_library_path = getenv(_LD("LIBRARY_PATH"));
602 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS"));
603 ld_preload = getenv(_LD("PRELOAD"));
604 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH"));
605 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL;
606 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH"));
607 if (library_path_rpath != NULL) {
608 if (library_path_rpath[0] == 'y' ||
609 library_path_rpath[0] == 'Y' ||
610 library_path_rpath[0] == '1')
611 ld_library_path_rpath = true;
613 ld_library_path_rpath = false;
615 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
616 (ld_library_path != NULL) || (ld_preload != NULL) ||
617 (ld_elf_hints_path != NULL) || ld_loadfltr;
618 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS"));
619 ld_utrace = getenv(_LD("UTRACE"));
621 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
622 ld_elf_hints_path = ld_elf_hints_default;
624 if (ld_debug != NULL && *ld_debug != '\0')
626 dbg("%s is initialized, base address = %p", __progname,
627 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
628 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
629 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
631 dbg("initializing thread locks");
635 * Load the main program, or process its program header if it is
638 if (fd != -1) { /* Load the main program. */
639 dbg("loading main program");
640 obj_main = map_object(fd, argv0, NULL);
642 if (obj_main == NULL)
644 max_stack_flags = obj_main->stack_flags;
645 } else { /* Main program already loaded. */
646 dbg("processing main program's program header");
647 assert(aux_info[AT_PHDR] != NULL);
648 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
649 assert(aux_info[AT_PHNUM] != NULL);
650 phnum = aux_info[AT_PHNUM]->a_un.a_val;
651 assert(aux_info[AT_PHENT] != NULL);
652 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
653 assert(aux_info[AT_ENTRY] != NULL);
654 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
655 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL)
659 if (aux_info[AT_EXECPATH] != NULL && fd == -1) {
660 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
661 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
662 if (kexecpath[0] == '/')
663 obj_main->path = kexecpath;
664 else if (getcwd(buf, sizeof(buf)) == NULL ||
665 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
666 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
667 obj_main->path = xstrdup(argv0);
669 obj_main->path = xstrdup(buf);
671 dbg("No AT_EXECPATH or direct exec");
672 obj_main->path = xstrdup(argv0);
674 dbg("obj_main path %s", obj_main->path);
675 obj_main->mainprog = true;
677 if (aux_info[AT_STACKPROT] != NULL &&
678 aux_info[AT_STACKPROT]->a_un.a_val != 0)
679 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
683 * Get the actual dynamic linker pathname from the executable if
684 * possible. (It should always be possible.) That ensures that
685 * gdb will find the right dynamic linker even if a non-standard
688 if (obj_main->interp != NULL &&
689 strcmp(obj_main->interp, obj_rtld.path) != 0) {
691 obj_rtld.path = xstrdup(obj_main->interp);
692 __progname = obj_rtld.path;
696 if (!digest_dynamic(obj_main, 0))
698 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
699 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
700 obj_main->dynsymcount);
702 linkmap_add(obj_main);
703 linkmap_add(&obj_rtld);
705 /* Link the main program into the list of objects. */
706 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
710 /* Initialize a fake symbol for resolving undefined weak references. */
711 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
712 sym_zero.st_shndx = SHN_UNDEF;
713 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
716 libmap_disable = (bool)lm_init(libmap_override);
718 dbg("loading LD_PRELOAD libraries");
719 if (load_preload_objects() == -1)
721 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
723 dbg("loading needed objects");
724 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE :
728 /* Make a list of all objects loaded at startup. */
729 last_interposer = obj_main;
730 TAILQ_FOREACH(obj, &obj_list, next) {
733 if (obj->z_interpose && obj != obj_main) {
734 objlist_put_after(&list_main, last_interposer, obj);
735 last_interposer = obj;
737 objlist_push_tail(&list_main, obj);
742 dbg("checking for required versions");
743 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
746 if (ld_tracing) { /* We're done */
747 trace_loaded_objects(obj_main);
751 if (getenv(_LD("DUMP_REL_PRE")) != NULL) {
752 dump_relocations(obj_main);
757 * Processing tls relocations requires having the tls offsets
758 * initialized. Prepare offsets before starting initial
759 * relocation processing.
761 dbg("initializing initial thread local storage offsets");
762 STAILQ_FOREACH(entry, &list_main, link) {
764 * Allocate all the initial objects out of the static TLS
765 * block even if they didn't ask for it.
767 allocate_tls_offset(entry->obj);
770 if (relocate_objects(obj_main,
771 ld_bind_now != NULL && *ld_bind_now != '\0',
772 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
775 dbg("doing copy relocations");
776 if (do_copy_relocations(obj_main) == -1)
779 if (getenv(_LD("DUMP_REL_POST")) != NULL) {
780 dump_relocations(obj_main);
787 * Setup TLS for main thread. This must be done after the
788 * relocations are processed, since tls initialization section
789 * might be the subject for relocations.
791 dbg("initializing initial thread local storage");
792 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
794 dbg("initializing key program variables");
795 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
796 set_program_var("environ", env);
797 set_program_var("__elf_aux_vector", aux);
799 /* Make a list of init functions to call. */
800 objlist_init(&initlist);
801 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)),
802 preload_tail, &initlist);
804 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
806 map_stacks_exec(NULL);
808 if (!obj_main->crt_no_init) {
810 * Make sure we don't call the main program's init and fini
811 * functions for binaries linked with old crt1 which calls
814 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
815 obj_main->preinit_array = obj_main->init_array =
816 obj_main->fini_array = (Elf_Addr)NULL;
820 * Execute MD initializers required before we call the objects'
826 /* Set osrel for direct-execed binary */
829 mib[2] = KERN_PROC_OSREL;
831 osrel = obj_main->osrel;
832 sz = sizeof(old_osrel);
833 dbg("setting osrel to %d", osrel);
834 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel));
837 wlock_acquire(rtld_bind_lock, &lockstate);
839 dbg("resolving ifuncs");
840 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL &&
841 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1)
844 rtld_exit_ptr = rtld_exit;
845 if (obj_main->crt_no_init)
847 objlist_call_init(&initlist, &lockstate);
848 _r_debug_postinit(&obj_main->linkmap);
849 objlist_clear(&initlist);
850 dbg("loading filtees");
851 TAILQ_FOREACH(obj, &obj_list, next) {
854 if (ld_loadfltr || obj->z_loadfltr)
855 load_filtees(obj, 0, &lockstate);
858 dbg("enforcing main obj relro");
859 if (obj_enforce_relro(obj_main) == -1)
862 lock_release(rtld_bind_lock, &lockstate);
864 dbg("transferring control to program entry point = %p", obj_main->entry);
866 /* Return the exit procedure and the program entry point. */
867 *exit_proc = rtld_exit_ptr;
869 return (func_ptr_type) obj_main->entry;
873 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
878 ptr = (void *)make_function_pointer(def, obj);
879 target = call_ifunc_resolver(ptr);
880 return ((void *)target);
884 * NB: MIPS uses a private version of this function (_mips_rtld_bind).
885 * Changes to this function should be applied there as well.
888 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
892 const Obj_Entry *defobj;
895 RtldLockState lockstate;
897 rlock_acquire(rtld_bind_lock, &lockstate);
898 if (sigsetjmp(lockstate.env, 0) != 0)
899 lock_upgrade(rtld_bind_lock, &lockstate);
901 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff);
903 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff);
905 where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
906 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
910 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
911 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
913 target = (Elf_Addr)(defobj->relocbase + def->st_value);
915 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
916 defobj->strtab + def->st_name, basename(obj->path),
917 (void *)target, basename(defobj->path));
920 * Write the new contents for the jmpslot. Note that depending on
921 * architecture, the value which we need to return back to the
922 * lazy binding trampoline may or may not be the target
923 * address. The value returned from reloc_jmpslot() is the value
924 * that the trampoline needs.
926 target = reloc_jmpslot(where, target, defobj, obj, rel);
927 lock_release(rtld_bind_lock, &lockstate);
932 * Error reporting function. Use it like printf. If formats the message
933 * into a buffer, and sets things up so that the next call to dlerror()
934 * will return the message.
937 _rtld_error(const char *fmt, ...)
939 static char buf[512];
943 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
946 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message);
950 * Return a dynamically-allocated copy of the current error message, if any.
955 return error_message == NULL ? NULL : xstrdup(error_message);
959 * Restore the current error message from a copy which was previously saved
960 * by errmsg_save(). The copy is freed.
963 errmsg_restore(char *saved_msg)
965 if (saved_msg == NULL)
966 error_message = NULL;
968 _rtld_error("%s", saved_msg);
974 basename(const char *name)
976 const char *p = strrchr(name, '/');
977 return p != NULL ? p + 1 : name;
980 static struct utsname uts;
983 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
984 const char *subst, bool may_free)
986 char *p, *p1, *res, *resp;
987 int subst_len, kw_len, subst_count, old_len, new_len;
992 * First, count the number of the keyword occurrences, to
993 * preallocate the final string.
995 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
1002 * If the keyword is not found, just return.
1004 * Return non-substituted string if resolution failed. We
1005 * cannot do anything more reasonable, the failure mode of the
1006 * caller is unresolved library anyway.
1008 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
1009 return (may_free ? real : xstrdup(real));
1011 subst = obj->origin_path;
1014 * There is indeed something to substitute. Calculate the
1015 * length of the resulting string, and allocate it.
1017 subst_len = strlen(subst);
1018 old_len = strlen(real);
1019 new_len = old_len + (subst_len - kw_len) * subst_count;
1020 res = xmalloc(new_len + 1);
1023 * Now, execute the substitution loop.
1025 for (p = real, resp = res, *resp = '\0';;) {
1028 /* Copy the prefix before keyword. */
1029 memcpy(resp, p, p1 - p);
1031 /* Keyword replacement. */
1032 memcpy(resp, subst, subst_len);
1040 /* Copy to the end of string and finish. */
1048 origin_subst(Obj_Entry *obj, const char *real)
1050 char *res1, *res2, *res3, *res4;
1052 if (obj == NULL || !trust)
1053 return (xstrdup(real));
1054 if (uts.sysname[0] == '\0') {
1055 if (uname(&uts) != 0) {
1056 _rtld_error("utsname failed: %d", errno);
1060 /* __DECONST is safe here since without may_free real is unchanged */
1061 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL,
1063 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
1064 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
1065 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
1072 const char *msg = dlerror();
1075 msg = "Fatal error";
1076 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": ");
1077 rtld_fdputstr(STDERR_FILENO, msg);
1078 rtld_fdputchar(STDERR_FILENO, '\n');
1083 * Process a shared object's DYNAMIC section, and save the important
1084 * information in its Obj_Entry structure.
1087 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
1088 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
1090 const Elf_Dyn *dynp;
1091 Needed_Entry **needed_tail = &obj->needed;
1092 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
1093 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
1094 const Elf_Hashelt *hashtab;
1095 const Elf32_Word *hashval;
1096 Elf32_Word bkt, nmaskwords;
1098 int plttype = DT_REL;
1102 *dyn_runpath = NULL;
1104 obj->bind_now = false;
1105 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
1106 switch (dynp->d_tag) {
1109 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr);
1113 obj->relsize = dynp->d_un.d_val;
1117 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1121 obj->pltrel = (const Elf_Rel *)
1122 (obj->relocbase + dynp->d_un.d_ptr);
1126 obj->pltrelsize = dynp->d_un.d_val;
1130 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr);
1134 obj->relasize = dynp->d_un.d_val;
1138 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1142 plttype = dynp->d_un.d_val;
1143 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1147 obj->symtab = (const Elf_Sym *)
1148 (obj->relocbase + dynp->d_un.d_ptr);
1152 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1156 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr);
1160 obj->strsize = dynp->d_un.d_val;
1164 obj->verneed = (const Elf_Verneed *)(obj->relocbase +
1169 obj->verneednum = dynp->d_un.d_val;
1173 obj->verdef = (const Elf_Verdef *)(obj->relocbase +
1178 obj->verdefnum = dynp->d_un.d_val;
1182 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1188 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1190 obj->nbuckets = hashtab[0];
1191 obj->nchains = hashtab[1];
1192 obj->buckets = hashtab + 2;
1193 obj->chains = obj->buckets + obj->nbuckets;
1194 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1195 obj->buckets != NULL;
1201 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1203 obj->nbuckets_gnu = hashtab[0];
1204 obj->symndx_gnu = hashtab[1];
1205 nmaskwords = hashtab[2];
1206 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1207 obj->maskwords_bm_gnu = nmaskwords - 1;
1208 obj->shift2_gnu = hashtab[3];
1209 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4);
1210 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1211 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1213 /* Number of bitmask words is required to be power of 2 */
1214 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1215 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1221 Needed_Entry *nep = NEW(Needed_Entry);
1222 nep->name = dynp->d_un.d_val;
1227 needed_tail = &nep->next;
1233 Needed_Entry *nep = NEW(Needed_Entry);
1234 nep->name = dynp->d_un.d_val;
1238 *needed_filtees_tail = nep;
1239 needed_filtees_tail = &nep->next;
1241 if (obj->linkmap.l_refname == NULL)
1242 obj->linkmap.l_refname = (char *)dynp->d_un.d_val;
1248 Needed_Entry *nep = NEW(Needed_Entry);
1249 nep->name = dynp->d_un.d_val;
1253 *needed_aux_filtees_tail = nep;
1254 needed_aux_filtees_tail = &nep->next;
1259 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr);
1263 obj->textrel = true;
1267 obj->symbolic = true;
1272 * We have to wait until later to process this, because we
1273 * might not have gotten the address of the string table yet.
1283 *dyn_runpath = dynp;
1287 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1290 case DT_PREINIT_ARRAY:
1291 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1294 case DT_PREINIT_ARRAYSZ:
1295 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1299 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1302 case DT_INIT_ARRAYSZ:
1303 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1307 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1311 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1314 case DT_FINI_ARRAYSZ:
1315 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1319 * Don't process DT_DEBUG on MIPS as the dynamic section
1320 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1326 dbg("Filling in DT_DEBUG entry");
1327 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug;
1332 if (dynp->d_un.d_val & DF_ORIGIN)
1333 obj->z_origin = true;
1334 if (dynp->d_un.d_val & DF_SYMBOLIC)
1335 obj->symbolic = true;
1336 if (dynp->d_un.d_val & DF_TEXTREL)
1337 obj->textrel = true;
1338 if (dynp->d_un.d_val & DF_BIND_NOW)
1339 obj->bind_now = true;
1340 if (dynp->d_un.d_val & DF_STATIC_TLS)
1341 obj->static_tls = true;
1344 case DT_MIPS_LOCAL_GOTNO:
1345 obj->local_gotno = dynp->d_un.d_val;
1348 case DT_MIPS_SYMTABNO:
1349 obj->symtabno = dynp->d_un.d_val;
1352 case DT_MIPS_GOTSYM:
1353 obj->gotsym = dynp->d_un.d_val;
1356 case DT_MIPS_RLD_MAP:
1357 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1360 case DT_MIPS_RLD_MAP_REL:
1361 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map
1362 // section relative to the address of the tag itself.
1363 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) =
1364 (Elf_Addr) &r_debug;
1367 case DT_MIPS_PLTGOT:
1368 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase +
1375 #ifdef __powerpc64__
1376 case DT_PPC64_GLINK:
1377 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1381 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr);
1387 if (dynp->d_un.d_val & DF_1_NOOPEN)
1388 obj->z_noopen = true;
1389 if (dynp->d_un.d_val & DF_1_ORIGIN)
1390 obj->z_origin = true;
1391 if (dynp->d_un.d_val & DF_1_GLOBAL)
1392 obj->z_global = true;
1393 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1394 obj->bind_now = true;
1395 if (dynp->d_un.d_val & DF_1_NODELETE)
1396 obj->z_nodelete = true;
1397 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1398 obj->z_loadfltr = true;
1399 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1400 obj->z_interpose = true;
1401 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1402 obj->z_nodeflib = true;
1403 if (dynp->d_un.d_val & DF_1_PIE)
1409 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1416 obj->traced = false;
1418 if (plttype == DT_RELA) {
1419 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1421 obj->pltrelasize = obj->pltrelsize;
1422 obj->pltrelsize = 0;
1425 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1426 if (obj->valid_hash_sysv)
1427 obj->dynsymcount = obj->nchains;
1428 else if (obj->valid_hash_gnu) {
1429 obj->dynsymcount = 0;
1430 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1431 if (obj->buckets_gnu[bkt] == 0)
1433 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1436 while ((*hashval++ & 1u) == 0);
1438 obj->dynsymcount += obj->symndx_gnu;
1441 if (obj->linkmap.l_refname != NULL)
1442 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj->
1447 obj_resolve_origin(Obj_Entry *obj)
1450 if (obj->origin_path != NULL)
1452 obj->origin_path = xmalloc(PATH_MAX);
1453 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1457 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1458 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1461 if (obj->z_origin && !obj_resolve_origin(obj))
1464 if (dyn_runpath != NULL) {
1465 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val;
1466 obj->runpath = origin_subst(obj, obj->runpath);
1467 } else if (dyn_rpath != NULL) {
1468 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val;
1469 obj->rpath = origin_subst(obj, obj->rpath);
1471 if (dyn_soname != NULL)
1472 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1477 digest_dynamic(Obj_Entry *obj, int early)
1479 const Elf_Dyn *dyn_rpath;
1480 const Elf_Dyn *dyn_soname;
1481 const Elf_Dyn *dyn_runpath;
1483 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1484 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath));
1488 * Process a shared object's program header. This is used only for the
1489 * main program, when the kernel has already loaded the main program
1490 * into memory before calling the dynamic linker. It creates and
1491 * returns an Obj_Entry structure.
1494 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1497 const Elf_Phdr *phlimit = phdr + phnum;
1499 Elf_Addr note_start, note_end;
1503 for (ph = phdr; ph < phlimit; ph++) {
1504 if (ph->p_type != PT_PHDR)
1508 obj->phsize = ph->p_memsz;
1509 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr;
1513 obj->stack_flags = PF_X | PF_R | PF_W;
1515 for (ph = phdr; ph < phlimit; ph++) {
1516 switch (ph->p_type) {
1519 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1523 if (nsegs == 0) { /* First load segment */
1524 obj->vaddrbase = trunc_page(ph->p_vaddr);
1525 obj->mapbase = obj->vaddrbase + obj->relocbase;
1526 } else { /* Last load segment */
1527 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1534 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1539 obj->tlssize = ph->p_memsz;
1540 obj->tlsalign = ph->p_align;
1541 obj->tlsinitsize = ph->p_filesz;
1542 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1543 obj->tlspoffset = ph->p_offset;
1547 obj->stack_flags = ph->p_flags;
1551 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1552 obj->relro_size = round_page(ph->p_memsz);
1556 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1557 note_end = note_start + ph->p_filesz;
1558 digest_notes(obj, note_start, note_end);
1563 _rtld_error("%s: too few PT_LOAD segments", path);
1572 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1574 const Elf_Note *note;
1575 const char *note_name;
1578 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1579 note = (const Elf_Note *)((const char *)(note + 1) +
1580 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1581 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1582 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1583 note->n_descsz != sizeof(int32_t))
1585 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1586 note->n_type != NT_FREEBSD_FEATURE_CTL &&
1587 note->n_type != NT_FREEBSD_NOINIT_TAG)
1589 note_name = (const char *)(note + 1);
1590 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1591 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1593 switch (note->n_type) {
1594 case NT_FREEBSD_ABI_TAG:
1595 /* FreeBSD osrel note */
1596 p = (uintptr_t)(note + 1);
1597 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1598 obj->osrel = *(const int32_t *)(p);
1599 dbg("note osrel %d", obj->osrel);
1601 case NT_FREEBSD_FEATURE_CTL:
1602 /* FreeBSD ABI feature control note */
1603 p = (uintptr_t)(note + 1);
1604 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1605 obj->fctl0 = *(const uint32_t *)(p);
1606 dbg("note fctl0 %#x", obj->fctl0);
1608 case NT_FREEBSD_NOINIT_TAG:
1609 /* FreeBSD 'crt does not call init' note */
1610 obj->crt_no_init = true;
1611 dbg("note crt_no_init");
1618 dlcheck(void *handle)
1622 TAILQ_FOREACH(obj, &obj_list, next) {
1623 if (obj == (Obj_Entry *) handle)
1627 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1628 _rtld_error("Invalid shared object handle %p", handle);
1635 * If the given object is already in the donelist, return true. Otherwise
1636 * add the object to the list and return false.
1639 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1643 for (i = 0; i < dlp->num_used; i++)
1644 if (dlp->objs[i] == obj)
1647 * Our donelist allocation should always be sufficient. But if
1648 * our threads locking isn't working properly, more shared objects
1649 * could have been loaded since we allocated the list. That should
1650 * never happen, but we'll handle it properly just in case it does.
1652 if (dlp->num_used < dlp->num_alloc)
1653 dlp->objs[dlp->num_used++] = obj;
1658 * Hash function for symbol table lookup. Don't even think about changing
1659 * this. It is specified by the System V ABI.
1662 elf_hash(const char *name)
1664 const unsigned char *p = (const unsigned char *) name;
1665 unsigned long h = 0;
1668 while (*p != '\0') {
1669 h = (h << 4) + *p++;
1670 if ((g = h & 0xf0000000) != 0)
1678 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1679 * unsigned in case it's implemented with a wider type.
1682 gnu_hash(const char *s)
1688 for (c = *s; c != '\0'; c = *++s)
1690 return (h & 0xffffffff);
1695 * Find the library with the given name, and return its full pathname.
1696 * The returned string is dynamically allocated. Generates an error
1697 * message and returns NULL if the library cannot be found.
1699 * If the second argument is non-NULL, then it refers to an already-
1700 * loaded shared object, whose library search path will be searched.
1702 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1703 * descriptor (which is close-on-exec) will be passed out via the third
1706 * The search order is:
1707 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1708 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1710 * DT_RUNPATH in the referencing file
1711 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1713 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1715 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1718 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1720 char *pathname, *refobj_path;
1722 bool nodeflib, objgiven;
1724 objgiven = refobj != NULL;
1726 if (libmap_disable || !objgiven ||
1727 (name = lm_find(refobj->path, xname)) == NULL)
1730 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1731 if (name[0] != '/' && !trust) {
1732 _rtld_error("Absolute pathname required "
1733 "for shared object \"%s\"", name);
1736 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1737 __DECONST(char *, name)));
1740 dbg(" Searching for \"%s\"", name);
1741 refobj_path = objgiven ? refobj->path : NULL;
1744 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1745 * back to pre-conforming behaviour if user requested so with
1746 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1749 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1750 pathname = search_library_path(name, ld_library_path,
1752 if (pathname != NULL)
1754 if (refobj != NULL) {
1755 pathname = search_library_path(name, refobj->rpath,
1757 if (pathname != NULL)
1760 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1761 if (pathname != NULL)
1763 pathname = search_library_path(name, gethints(false),
1765 if (pathname != NULL)
1767 pathname = search_library_path(name, ld_standard_library_path,
1769 if (pathname != NULL)
1772 nodeflib = objgiven ? refobj->z_nodeflib : false;
1774 pathname = search_library_path(name, refobj->rpath,
1776 if (pathname != NULL)
1779 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1780 pathname = search_library_path(name, obj_main->rpath,
1782 if (pathname != NULL)
1785 pathname = search_library_path(name, ld_library_path,
1787 if (pathname != NULL)
1790 pathname = search_library_path(name, refobj->runpath,
1792 if (pathname != NULL)
1795 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1796 if (pathname != NULL)
1798 pathname = search_library_path(name, gethints(nodeflib),
1800 if (pathname != NULL)
1802 if (objgiven && !nodeflib) {
1803 pathname = search_library_path(name,
1804 ld_standard_library_path, refobj_path, fdp);
1805 if (pathname != NULL)
1810 if (objgiven && refobj->path != NULL) {
1811 _rtld_error("Shared object \"%s\" not found, "
1812 "required by \"%s\"", name, basename(refobj->path));
1814 _rtld_error("Shared object \"%s\" not found", name);
1820 * Given a symbol number in a referencing object, find the corresponding
1821 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1822 * no definition was found. Returns a pointer to the Obj_Entry of the
1823 * defining object via the reference parameter DEFOBJ_OUT.
1826 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1827 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1828 RtldLockState *lockstate)
1832 const Obj_Entry *defobj;
1833 const Ver_Entry *ve;
1839 * If we have already found this symbol, get the information from
1842 if (symnum >= refobj->dynsymcount)
1843 return NULL; /* Bad object */
1844 if (cache != NULL && cache[symnum].sym != NULL) {
1845 *defobj_out = cache[symnum].obj;
1846 return cache[symnum].sym;
1849 ref = refobj->symtab + symnum;
1850 name = refobj->strtab + ref->st_name;
1856 * We don't have to do a full scale lookup if the symbol is local.
1857 * We know it will bind to the instance in this load module; to
1858 * which we already have a pointer (ie ref). By not doing a lookup,
1859 * we not only improve performance, but it also avoids unresolvable
1860 * symbols when local symbols are not in the hash table. This has
1861 * been seen with the ia64 toolchain.
1863 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1864 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1865 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1868 symlook_init(&req, name);
1870 ve = req.ventry = fetch_ventry(refobj, symnum);
1871 req.lockstate = lockstate;
1872 res = symlook_default(&req, refobj);
1875 defobj = req.defobj_out;
1883 * If we found no definition and the reference is weak, treat the
1884 * symbol as having the value zero.
1886 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1892 *defobj_out = defobj;
1893 /* Record the information in the cache to avoid subsequent lookups. */
1894 if (cache != NULL) {
1895 cache[symnum].sym = def;
1896 cache[symnum].obj = defobj;
1899 if (refobj != &obj_rtld)
1900 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name,
1901 ve != NULL ? "@" : "", ve != NULL ? ve->name : "");
1907 * Return the search path from the ldconfig hints file, reading it if
1908 * necessary. If nostdlib is true, then the default search paths are
1909 * not added to result.
1911 * Returns NULL if there are problems with the hints file,
1912 * or if the search path there is empty.
1915 gethints(bool nostdlib)
1917 static char *filtered_path;
1918 static const char *hints;
1919 static struct elfhints_hdr hdr;
1920 struct fill_search_info_args sargs, hargs;
1921 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1922 struct dl_serpath *SLPpath, *hintpath;
1924 struct stat hint_stat;
1925 unsigned int SLPndx, hintndx, fndx, fcount;
1931 /* First call, read the hints file */
1932 if (hints == NULL) {
1933 /* Keep from trying again in case the hints file is bad. */
1936 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1940 * Check of hdr.dirlistlen value against type limit
1941 * intends to pacify static analyzers. Further
1942 * paranoia leads to checks that dirlist is fully
1943 * contained in the file range.
1945 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1946 hdr.magic != ELFHINTS_MAGIC ||
1947 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 ||
1948 fstat(fd, &hint_stat) == -1) {
1955 if (dl + hdr.dirlist < dl)
1958 if (dl + hdr.dirlistlen < dl)
1960 dl += hdr.dirlistlen;
1961 if (dl > hint_stat.st_size)
1963 p = xmalloc(hdr.dirlistlen + 1);
1964 if (pread(fd, p, hdr.dirlistlen + 1,
1965 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 ||
1966 p[hdr.dirlistlen] != '\0') {
1975 * If caller agreed to receive list which includes the default
1976 * paths, we are done. Otherwise, if we still did not
1977 * calculated filtered result, do it now.
1980 return (hints[0] != '\0' ? hints : NULL);
1981 if (filtered_path != NULL)
1985 * Obtain the list of all configured search paths, and the
1986 * list of the default paths.
1988 * First estimate the size of the results.
1990 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1992 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1995 sargs.request = RTLD_DI_SERINFOSIZE;
1996 sargs.serinfo = &smeta;
1997 hargs.request = RTLD_DI_SERINFOSIZE;
1998 hargs.serinfo = &hmeta;
2000 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
2002 path_enumerate(hints, fill_search_info, NULL, &hargs);
2004 SLPinfo = xmalloc(smeta.dls_size);
2005 hintinfo = xmalloc(hmeta.dls_size);
2008 * Next fetch both sets of paths.
2010 sargs.request = RTLD_DI_SERINFO;
2011 sargs.serinfo = SLPinfo;
2012 sargs.serpath = &SLPinfo->dls_serpath[0];
2013 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
2015 hargs.request = RTLD_DI_SERINFO;
2016 hargs.serinfo = hintinfo;
2017 hargs.serpath = &hintinfo->dls_serpath[0];
2018 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
2020 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
2022 path_enumerate(hints, fill_search_info, NULL, &hargs);
2025 * Now calculate the difference between two sets, by excluding
2026 * standard paths from the full set.
2030 filtered_path = xmalloc(hdr.dirlistlen + 1);
2031 hintpath = &hintinfo->dls_serpath[0];
2032 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
2034 SLPpath = &SLPinfo->dls_serpath[0];
2036 * Check each standard path against current.
2038 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
2039 /* matched, skip the path */
2040 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
2048 * Not matched against any standard path, add the path
2049 * to result. Separate consequtive paths with ':'.
2052 filtered_path[fndx] = ':';
2056 flen = strlen(hintpath->dls_name);
2057 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
2060 filtered_path[fndx] = '\0';
2066 return (filtered_path[0] != '\0' ? filtered_path : NULL);
2070 init_dag(Obj_Entry *root)
2072 const Needed_Entry *needed;
2073 const Objlist_Entry *elm;
2076 if (root->dag_inited)
2078 donelist_init(&donelist);
2080 /* Root object belongs to own DAG. */
2081 objlist_push_tail(&root->dldags, root);
2082 objlist_push_tail(&root->dagmembers, root);
2083 donelist_check(&donelist, root);
2086 * Add dependencies of root object to DAG in breadth order
2087 * by exploiting the fact that each new object get added
2088 * to the tail of the dagmembers list.
2090 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2091 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
2092 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
2094 objlist_push_tail(&needed->obj->dldags, root);
2095 objlist_push_tail(&root->dagmembers, needed->obj);
2098 root->dag_inited = true;
2102 init_marker(Obj_Entry *marker)
2105 bzero(marker, sizeof(*marker));
2106 marker->marker = true;
2110 globallist_curr(const Obj_Entry *obj)
2117 return (__DECONST(Obj_Entry *, obj));
2118 obj = TAILQ_PREV(obj, obj_entry_q, next);
2123 globallist_next(const Obj_Entry *obj)
2127 obj = TAILQ_NEXT(obj, next);
2131 return (__DECONST(Obj_Entry *, obj));
2135 /* Prevent the object from being unmapped while the bind lock is dropped. */
2137 hold_object(Obj_Entry *obj)
2144 unhold_object(Obj_Entry *obj)
2147 assert(obj->holdcount > 0);
2148 if (--obj->holdcount == 0 && obj->unholdfree)
2149 release_object(obj);
2153 process_z(Obj_Entry *root)
2155 const Objlist_Entry *elm;
2159 * Walk over object DAG and process every dependent object
2160 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2161 * to grow their own DAG.
2163 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2164 * symlook_global() to work.
2166 * For DF_1_NODELETE, the DAG should have its reference upped.
2168 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2172 if (obj->z_nodelete && !obj->ref_nodel) {
2173 dbg("obj %s -z nodelete", obj->path);
2176 obj->ref_nodel = true;
2178 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2179 dbg("obj %s -z global", obj->path);
2180 objlist_push_tail(&list_global, obj);
2187 parse_rtld_phdr(Obj_Entry *obj)
2190 Elf_Addr note_start, note_end;
2192 obj->stack_flags = PF_X | PF_R | PF_W;
2193 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr +
2194 obj->phsize; ph++) {
2195 switch (ph->p_type) {
2197 obj->stack_flags = ph->p_flags;
2200 obj->relro_page = obj->relocbase +
2201 trunc_page(ph->p_vaddr);
2202 obj->relro_size = round_page(ph->p_memsz);
2205 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
2206 note_end = note_start + ph->p_filesz;
2207 digest_notes(obj, note_start, note_end);
2214 * Initialize the dynamic linker. The argument is the address at which
2215 * the dynamic linker has been mapped into memory. The primary task of
2216 * this function is to relocate the dynamic linker.
2219 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2221 Obj_Entry objtmp; /* Temporary rtld object */
2222 const Elf_Ehdr *ehdr;
2223 const Elf_Dyn *dyn_rpath;
2224 const Elf_Dyn *dyn_soname;
2225 const Elf_Dyn *dyn_runpath;
2227 #ifdef RTLD_INIT_PAGESIZES_EARLY
2228 /* The page size is required by the dynamic memory allocator. */
2229 init_pagesizes(aux_info);
2233 * Conjure up an Obj_Entry structure for the dynamic linker.
2235 * The "path" member can't be initialized yet because string constants
2236 * cannot yet be accessed. Below we will set it correctly.
2238 memset(&objtmp, 0, sizeof(objtmp));
2241 objtmp.mapbase = mapbase;
2243 objtmp.relocbase = mapbase;
2246 objtmp.dynamic = rtld_dynamic(&objtmp);
2247 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2248 assert(objtmp.needed == NULL);
2249 #if !defined(__mips__)
2250 /* MIPS has a bogus DT_TEXTREL. */
2251 assert(!objtmp.textrel);
2254 * Temporarily put the dynamic linker entry into the object list, so
2255 * that symbols can be found.
2257 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2259 ehdr = (Elf_Ehdr *)mapbase;
2260 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2261 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]);
2263 /* Initialize the object list. */
2264 TAILQ_INIT(&obj_list);
2266 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2267 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2269 #ifndef RTLD_INIT_PAGESIZES_EARLY
2270 /* The page size is required by the dynamic memory allocator. */
2271 init_pagesizes(aux_info);
2274 if (aux_info[AT_OSRELDATE] != NULL)
2275 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2277 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2279 /* Replace the path with a dynamically allocated copy. */
2280 obj_rtld.path = xstrdup(ld_path_rtld);
2282 parse_rtld_phdr(&obj_rtld);
2283 obj_enforce_relro(&obj_rtld);
2285 r_debug.r_brk = r_debug_state;
2286 r_debug.r_state = RT_CONSISTENT;
2290 * Retrieve the array of supported page sizes. The kernel provides the page
2291 * sizes in increasing order.
2294 init_pagesizes(Elf_Auxinfo **aux_info)
2296 static size_t psa[MAXPAGESIZES];
2300 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
2302 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2303 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2306 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2309 /* As a fallback, retrieve the base page size. */
2310 size = sizeof(psa[0]);
2311 if (aux_info[AT_PAGESZ] != NULL) {
2312 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2316 mib[1] = HW_PAGESIZE;
2320 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2321 _rtld_error("sysctl for hw.pagesize(s) failed");
2327 npagesizes = size / sizeof(pagesizes[0]);
2328 /* Discard any invalid entries at the end of the array. */
2329 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2334 * Add the init functions from a needed object list (and its recursive
2335 * needed objects) to "list". This is not used directly; it is a helper
2336 * function for initlist_add_objects(). The write lock must be held
2337 * when this function is called.
2340 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
2342 /* Recursively process the successor needed objects. */
2343 if (needed->next != NULL)
2344 initlist_add_neededs(needed->next, list);
2346 /* Process the current needed object. */
2347 if (needed->obj != NULL)
2348 initlist_add_objects(needed->obj, needed->obj, list);
2352 * Scan all of the DAGs rooted in the range of objects from "obj" to
2353 * "tail" and add their init functions to "list". This recurses over
2354 * the DAGs and ensure the proper init ordering such that each object's
2355 * needed libraries are initialized before the object itself. At the
2356 * same time, this function adds the objects to the global finalization
2357 * list "list_fini" in the opposite order. The write lock must be
2358 * held when this function is called.
2361 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2365 if (obj->init_scanned || obj->init_done)
2367 obj->init_scanned = true;
2369 /* Recursively process the successor objects. */
2370 nobj = globallist_next(obj);
2371 if (nobj != NULL && obj != tail)
2372 initlist_add_objects(nobj, tail, list);
2374 /* Recursively process the needed objects. */
2375 if (obj->needed != NULL)
2376 initlist_add_neededs(obj->needed, list);
2377 if (obj->needed_filtees != NULL)
2378 initlist_add_neededs(obj->needed_filtees, list);
2379 if (obj->needed_aux_filtees != NULL)
2380 initlist_add_neededs(obj->needed_aux_filtees, list);
2382 /* Add the object to the init list. */
2383 objlist_push_tail(list, obj);
2385 /* Add the object to the global fini list in the reverse order. */
2386 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2387 && !obj->on_fini_list) {
2388 objlist_push_head(&list_fini, obj);
2389 obj->on_fini_list = true;
2394 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2398 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2400 Needed_Entry *needed, *needed1;
2402 for (needed = n; needed != NULL; needed = needed->next) {
2403 if (needed->obj != NULL) {
2404 dlclose_locked(needed->obj, lockstate);
2408 for (needed = n; needed != NULL; needed = needed1) {
2409 needed1 = needed->next;
2415 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2418 free_needed_filtees(obj->needed_filtees, lockstate);
2419 obj->needed_filtees = NULL;
2420 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2421 obj->needed_aux_filtees = NULL;
2422 obj->filtees_loaded = false;
2426 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2427 RtldLockState *lockstate)
2430 for (; needed != NULL; needed = needed->next) {
2431 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2432 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2433 RTLD_LOCAL, lockstate);
2438 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2441 lock_restart_for_upgrade(lockstate);
2442 if (!obj->filtees_loaded) {
2443 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2444 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2445 obj->filtees_loaded = true;
2450 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2454 for (; needed != NULL; needed = needed->next) {
2455 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2456 flags & ~RTLD_LO_NOLOAD);
2457 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2464 * Given a shared object, traverse its list of needed objects, and load
2465 * each of them. Returns 0 on success. Generates an error message and
2466 * returns -1 on failure.
2469 load_needed_objects(Obj_Entry *first, int flags)
2473 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2476 if (process_needed(obj, obj->needed, flags) == -1)
2483 load_preload_objects(void)
2485 char *p = ld_preload;
2487 static const char delim[] = " \t:;";
2492 p += strspn(p, delim);
2493 while (*p != '\0') {
2494 size_t len = strcspn(p, delim);
2499 obj = load_object(p, -1, NULL, 0);
2501 return -1; /* XXX - cleanup */
2502 obj->z_interpose = true;
2505 p += strspn(p, delim);
2507 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2512 printable_path(const char *path)
2515 return (path == NULL ? "<unknown>" : path);
2519 * Load a shared object into memory, if it is not already loaded. The
2520 * object may be specified by name or by user-supplied file descriptor
2521 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2524 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2528 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2537 TAILQ_FOREACH(obj, &obj_list, next) {
2538 if (obj->marker || obj->doomed)
2540 if (object_match_name(obj, name))
2544 path = find_library(name, refobj, &fd);
2552 * search_library_pathfds() opens a fresh file descriptor for the
2553 * library, so there is no need to dup().
2555 } else if (fd_u == -1) {
2557 * If we didn't find a match by pathname, or the name is not
2558 * supplied, open the file and check again by device and inode.
2559 * This avoids false mismatches caused by multiple links or ".."
2562 * To avoid a race, we open the file and use fstat() rather than
2565 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2566 _rtld_error("Cannot open \"%s\"", path);
2571 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2573 _rtld_error("Cannot dup fd");
2578 if (fstat(fd, &sb) == -1) {
2579 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2584 TAILQ_FOREACH(obj, &obj_list, next) {
2585 if (obj->marker || obj->doomed)
2587 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2590 if (obj != NULL && name != NULL) {
2591 object_add_name(obj, name);
2596 if (flags & RTLD_LO_NOLOAD) {
2602 /* First use of this object, so we must map it in */
2603 obj = do_load_object(fd, name, path, &sb, flags);
2612 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2619 * but first, make sure that environment variables haven't been
2620 * used to circumvent the noexec flag on a filesystem.
2622 if (dangerous_ld_env) {
2623 if (fstatfs(fd, &fs) != 0) {
2624 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2627 if (fs.f_flags & MNT_NOEXEC) {
2628 _rtld_error("Cannot execute objects on %s", fs.f_mntonname);
2632 dbg("loading \"%s\"", printable_path(path));
2633 obj = map_object(fd, printable_path(path), sbp);
2638 * If DT_SONAME is present in the object, digest_dynamic2 already
2639 * added it to the object names.
2642 object_add_name(obj, name);
2644 if (!digest_dynamic(obj, 0))
2646 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2647 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2648 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) {
2649 dbg("refusing to load PIE executable \"%s\"", obj->path);
2650 _rtld_error("Cannot load PIE binary %s as DSO", obj->path);
2653 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2655 dbg("refusing to load non-loadable \"%s\"", obj->path);
2656 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2660 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2661 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2664 linkmap_add(obj); /* for GDB & dlinfo() */
2665 max_stack_flags |= obj->stack_flags;
2667 dbg(" %p .. %p: %s", obj->mapbase,
2668 obj->mapbase + obj->mapsize - 1, obj->path);
2670 dbg(" WARNING: %s has impure text", obj->path);
2671 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2677 munmap(obj->mapbase, obj->mapsize);
2683 obj_from_addr(const void *addr)
2687 TAILQ_FOREACH(obj, &obj_list, next) {
2690 if (addr < (void *) obj->mapbase)
2692 if (addr < (void *)(obj->mapbase + obj->mapsize))
2701 Elf_Addr *preinit_addr;
2704 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2705 if (preinit_addr == NULL)
2708 for (index = 0; index < obj_main->preinit_array_num; index++) {
2709 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2710 dbg("calling preinit function for %s at %p", obj_main->path,
2711 (void *)preinit_addr[index]);
2712 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2713 0, 0, obj_main->path);
2714 call_init_pointer(obj_main, preinit_addr[index]);
2720 * Call the finalization functions for each of the objects in "list"
2721 * belonging to the DAG of "root" and referenced once. If NULL "root"
2722 * is specified, every finalization function will be called regardless
2723 * of the reference count and the list elements won't be freed. All of
2724 * the objects are expected to have non-NULL fini functions.
2727 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2731 Elf_Addr *fini_addr;
2734 assert(root == NULL || root->refcount == 1);
2737 root->doomed = true;
2740 * Preserve the current error message since a fini function might
2741 * call into the dynamic linker and overwrite it.
2743 saved_msg = errmsg_save();
2745 STAILQ_FOREACH(elm, list, link) {
2746 if (root != NULL && (elm->obj->refcount != 1 ||
2747 objlist_find(&root->dagmembers, elm->obj) == NULL))
2749 /* Remove object from fini list to prevent recursive invocation. */
2750 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2751 /* Ensure that new references cannot be acquired. */
2752 elm->obj->doomed = true;
2754 hold_object(elm->obj);
2755 lock_release(rtld_bind_lock, lockstate);
2757 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2758 * When this happens, DT_FINI_ARRAY is processed first.
2760 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2761 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2762 for (index = elm->obj->fini_array_num - 1; index >= 0;
2764 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2765 dbg("calling fini function for %s at %p",
2766 elm->obj->path, (void *)fini_addr[index]);
2767 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2768 (void *)fini_addr[index], 0, 0, elm->obj->path);
2769 call_initfini_pointer(elm->obj, fini_addr[index]);
2773 if (elm->obj->fini != (Elf_Addr)NULL) {
2774 dbg("calling fini function for %s at %p", elm->obj->path,
2775 (void *)elm->obj->fini);
2776 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2777 0, 0, elm->obj->path);
2778 call_initfini_pointer(elm->obj, elm->obj->fini);
2780 wlock_acquire(rtld_bind_lock, lockstate);
2781 unhold_object(elm->obj);
2782 /* No need to free anything if process is going down. */
2786 * We must restart the list traversal after every fini call
2787 * because a dlclose() call from the fini function or from
2788 * another thread might have modified the reference counts.
2792 } while (elm != NULL);
2793 errmsg_restore(saved_msg);
2797 * Call the initialization functions for each of the objects in
2798 * "list". All of the objects are expected to have non-NULL init
2802 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2807 Elf_Addr *init_addr;
2808 void (*reg)(void (*)(void));
2812 * Clean init_scanned flag so that objects can be rechecked and
2813 * possibly initialized earlier if any of vectors called below
2814 * cause the change by using dlopen.
2816 TAILQ_FOREACH(obj, &obj_list, next) {
2819 obj->init_scanned = false;
2823 * Preserve the current error message since an init function might
2824 * call into the dynamic linker and overwrite it.
2826 saved_msg = errmsg_save();
2827 STAILQ_FOREACH(elm, list, link) {
2828 if (elm->obj->init_done) /* Initialized early. */
2831 * Race: other thread might try to use this object before current
2832 * one completes the initialization. Not much can be done here
2833 * without better locking.
2835 elm->obj->init_done = true;
2836 hold_object(elm->obj);
2838 if (elm->obj == obj_main && obj_main->crt_no_init) {
2839 reg = (void (*)(void (*)(void)))get_program_var_addr(
2840 "__libc_atexit", lockstate);
2842 lock_release(rtld_bind_lock, lockstate);
2845 rtld_exit_ptr = rtld_nop_exit;
2849 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2850 * When this happens, DT_INIT is processed first.
2852 if (elm->obj->init != (Elf_Addr)NULL) {
2853 dbg("calling init function for %s at %p", elm->obj->path,
2854 (void *)elm->obj->init);
2855 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2856 0, 0, elm->obj->path);
2857 call_initfini_pointer(elm->obj, elm->obj->init);
2859 init_addr = (Elf_Addr *)elm->obj->init_array;
2860 if (init_addr != NULL) {
2861 for (index = 0; index < elm->obj->init_array_num; index++) {
2862 if (init_addr[index] != 0 && init_addr[index] != 1) {
2863 dbg("calling init function for %s at %p", elm->obj->path,
2864 (void *)init_addr[index]);
2865 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2866 (void *)init_addr[index], 0, 0, elm->obj->path);
2867 call_init_pointer(elm->obj, init_addr[index]);
2871 wlock_acquire(rtld_bind_lock, lockstate);
2872 unhold_object(elm->obj);
2874 errmsg_restore(saved_msg);
2878 objlist_clear(Objlist *list)
2882 while (!STAILQ_EMPTY(list)) {
2883 elm = STAILQ_FIRST(list);
2884 STAILQ_REMOVE_HEAD(list, link);
2889 static Objlist_Entry *
2890 objlist_find(Objlist *list, const Obj_Entry *obj)
2894 STAILQ_FOREACH(elm, list, link)
2895 if (elm->obj == obj)
2901 objlist_init(Objlist *list)
2907 objlist_push_head(Objlist *list, Obj_Entry *obj)
2911 elm = NEW(Objlist_Entry);
2913 STAILQ_INSERT_HEAD(list, elm, link);
2917 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2921 elm = NEW(Objlist_Entry);
2923 STAILQ_INSERT_TAIL(list, elm, link);
2927 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2929 Objlist_Entry *elm, *listelm;
2931 STAILQ_FOREACH(listelm, list, link) {
2932 if (listelm->obj == listobj)
2935 elm = NEW(Objlist_Entry);
2937 if (listelm != NULL)
2938 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2940 STAILQ_INSERT_TAIL(list, elm, link);
2944 objlist_remove(Objlist *list, Obj_Entry *obj)
2948 if ((elm = objlist_find(list, obj)) != NULL) {
2949 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2955 * Relocate dag rooted in the specified object.
2956 * Returns 0 on success, or -1 on failure.
2960 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2961 int flags, RtldLockState *lockstate)
2967 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2968 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2977 * Prepare for, or clean after, relocating an object marked with
2978 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
2979 * segments are remapped read-write. After relocations are done, the
2980 * segment's permissions are returned back to the modes specified in
2981 * the phdrs. If any relocation happened, or always for wired
2982 * program, COW is triggered.
2985 reloc_textrel_prot(Obj_Entry *obj, bool before)
2992 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
2994 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
2996 base = obj->relocbase + trunc_page(ph->p_vaddr);
2997 sz = round_page(ph->p_vaddr + ph->p_filesz) -
2998 trunc_page(ph->p_vaddr);
2999 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0);
3000 if (mprotect(base, sz, prot) == -1) {
3001 _rtld_error("%s: Cannot write-%sable text segment: %s",
3002 obj->path, before ? "en" : "dis",
3003 rtld_strerror(errno));
3011 * Relocate single object.
3012 * Returns 0 on success, or -1 on failure.
3015 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
3016 int flags, RtldLockState *lockstate)
3021 obj->relocated = true;
3023 dbg("relocating \"%s\"", obj->path);
3025 if (obj->symtab == NULL || obj->strtab == NULL ||
3026 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
3027 _rtld_error("%s: Shared object has no run-time symbol table",
3032 /* There are relocations to the write-protected text segment. */
3033 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
3036 /* Process the non-PLT non-IFUNC relocations. */
3037 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
3040 /* Re-protected the text segment. */
3041 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
3044 /* Set the special PLT or GOT entries. */
3047 /* Process the PLT relocations. */
3048 if (reloc_plt(obj, flags, lockstate) == -1)
3050 /* Relocate the jump slots if we are doing immediate binding. */
3051 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags,
3055 if (!obj->mainprog && obj_enforce_relro(obj) == -1)
3059 * Set up the magic number and version in the Obj_Entry. These
3060 * were checked in the crt1.o from the original ElfKit, so we
3061 * set them for backward compatibility.
3063 obj->magic = RTLD_MAGIC;
3064 obj->version = RTLD_VERSION;
3070 * Relocate newly-loaded shared objects. The argument is a pointer to
3071 * the Obj_Entry for the first such object. All objects from the first
3072 * to the end of the list of objects are relocated. Returns 0 on success,
3076 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
3077 int flags, RtldLockState *lockstate)
3082 for (error = 0, obj = first; obj != NULL;
3083 obj = TAILQ_NEXT(obj, next)) {
3086 error = relocate_object(obj, bind_now, rtldobj, flags,
3095 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
3096 * referencing STT_GNU_IFUNC symbols is postponed till the other
3097 * relocations are done. The indirect functions specified as
3098 * ifunc are allowed to call other symbols, so we need to have
3099 * objects relocated before asking for resolution from indirects.
3101 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
3102 * instead of the usual lazy handling of PLT slots. It is
3103 * consistent with how GNU does it.
3106 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
3107 RtldLockState *lockstate)
3110 if (obj->ifuncs_resolved)
3112 obj->ifuncs_resolved = true;
3113 if (!obj->irelative && !obj->irelative_nonplt &&
3114 !((obj->bind_now || bind_now) && obj->gnu_ifunc) &&
3115 !obj->non_plt_gnu_ifunc)
3117 if (obj_disable_relro(obj) == -1 ||
3118 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) ||
3119 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj,
3120 lockstate) == -1) ||
3121 ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
3122 reloc_gnu_ifunc(obj, flags, lockstate) == -1) ||
3123 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld,
3124 flags | SYMLOOK_IFUNC, lockstate) == -1) ||
3125 obj_enforce_relro(obj) == -1)
3131 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
3132 RtldLockState *lockstate)
3137 STAILQ_FOREACH(elm, list, link) {
3141 if (resolve_object_ifunc(obj, bind_now, flags,
3149 * Cleanup procedure. It will be called (by the atexit mechanism) just
3150 * before the process exits.
3155 RtldLockState lockstate;
3157 wlock_acquire(rtld_bind_lock, &lockstate);
3159 objlist_call_fini(&list_fini, NULL, &lockstate);
3160 /* No need to remove the items from the list, since we are exiting. */
3161 if (!libmap_disable)
3163 lock_release(rtld_bind_lock, &lockstate);
3172 * Iterate over a search path, translate each element, and invoke the
3173 * callback on the result.
3176 path_enumerate(const char *path, path_enum_proc callback,
3177 const char *refobj_path, void *arg)
3183 path += strspn(path, ":;");
3184 while (*path != '\0') {
3188 len = strcspn(path, ":;");
3189 trans = lm_findn(refobj_path, path, len);
3191 res = callback(trans, strlen(trans), arg);
3193 res = callback(path, len, arg);
3199 path += strspn(path, ":;");
3205 struct try_library_args {
3214 try_library_path(const char *dir, size_t dirlen, void *param)
3216 struct try_library_args *arg;
3220 if (*dir == '/' || trust) {
3223 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3226 pathname = arg->buffer;
3227 strncpy(pathname, dir, dirlen);
3228 pathname[dirlen] = '/';
3229 strcpy(pathname + dirlen + 1, arg->name);
3231 dbg(" Trying \"%s\"", pathname);
3232 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3234 dbg(" Opened \"%s\", fd %d", pathname, fd);
3235 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3236 strcpy(pathname, arg->buffer);
3240 dbg(" Failed to open \"%s\": %s",
3241 pathname, rtld_strerror(errno));
3248 search_library_path(const char *name, const char *path,
3249 const char *refobj_path, int *fdp)
3252 struct try_library_args arg;
3258 arg.namelen = strlen(name);
3259 arg.buffer = xmalloc(PATH_MAX);
3260 arg.buflen = PATH_MAX;
3263 p = path_enumerate(path, try_library_path, refobj_path, &arg);
3273 * Finds the library with the given name using the directory descriptors
3274 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3276 * Returns a freshly-opened close-on-exec file descriptor for the library,
3277 * or -1 if the library cannot be found.
3280 search_library_pathfds(const char *name, const char *path, int *fdp)
3282 char *envcopy, *fdstr, *found, *last_token;
3286 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3288 /* Don't load from user-specified libdirs into setuid binaries. */
3292 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3296 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3297 if (name[0] == '/') {
3298 dbg("Absolute path (%s) passed to %s", name, __func__);
3303 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3304 * copy of the path, as strtok_r rewrites separator tokens
3308 envcopy = xstrdup(path);
3309 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3310 fdstr = strtok_r(NULL, ":", &last_token)) {
3311 dirfd = parse_integer(fdstr);
3313 _rtld_error("failed to parse directory FD: '%s'",
3317 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3320 len = strlen(fdstr) + strlen(name) + 3;
3321 found = xmalloc(len);
3322 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
3323 _rtld_error("error generating '%d/%s'",
3327 dbg("open('%s') => %d", found, fd);
3338 dlclose(void *handle)
3340 RtldLockState lockstate;
3343 wlock_acquire(rtld_bind_lock, &lockstate);
3344 error = dlclose_locked(handle, &lockstate);
3345 lock_release(rtld_bind_lock, &lockstate);
3350 dlclose_locked(void *handle, RtldLockState *lockstate)
3354 root = dlcheck(handle);
3357 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3360 /* Unreference the object and its dependencies. */
3361 root->dl_refcount--;
3363 if (root->refcount == 1) {
3365 * The object will be no longer referenced, so we must unload it.
3366 * First, call the fini functions.
3368 objlist_call_fini(&list_fini, root, lockstate);
3372 /* Finish cleaning up the newly-unreferenced objects. */
3373 GDB_STATE(RT_DELETE,&root->linkmap);
3374 unload_object(root, lockstate);
3375 GDB_STATE(RT_CONSISTENT,NULL);
3379 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3386 char *msg = error_message;
3387 error_message = NULL;
3392 * This function is deprecated and has no effect.
3395 dllockinit(void *context,
3396 void *(*_lock_create)(void *context) __unused,
3397 void (*_rlock_acquire)(void *lock) __unused,
3398 void (*_wlock_acquire)(void *lock) __unused,
3399 void (*_lock_release)(void *lock) __unused,
3400 void (*_lock_destroy)(void *lock) __unused,
3401 void (*context_destroy)(void *context))
3403 static void *cur_context;
3404 static void (*cur_context_destroy)(void *);
3406 /* Just destroy the context from the previous call, if necessary. */
3407 if (cur_context_destroy != NULL)
3408 cur_context_destroy(cur_context);
3409 cur_context = context;
3410 cur_context_destroy = context_destroy;
3414 dlopen(const char *name, int mode)
3417 return (rtld_dlopen(name, -1, mode));
3421 fdlopen(int fd, int mode)
3424 return (rtld_dlopen(NULL, fd, mode));
3428 rtld_dlopen(const char *name, int fd, int mode)
3430 RtldLockState lockstate;
3433 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3434 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3435 if (ld_tracing != NULL) {
3436 rlock_acquire(rtld_bind_lock, &lockstate);
3437 if (sigsetjmp(lockstate.env, 0) != 0)
3438 lock_upgrade(rtld_bind_lock, &lockstate);
3439 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate));
3440 lock_release(rtld_bind_lock, &lockstate);
3442 lo_flags = RTLD_LO_DLOPEN;
3443 if (mode & RTLD_NODELETE)
3444 lo_flags |= RTLD_LO_NODELETE;
3445 if (mode & RTLD_NOLOAD)
3446 lo_flags |= RTLD_LO_NOLOAD;
3447 if (mode & RTLD_DEEPBIND)
3448 lo_flags |= RTLD_LO_DEEPBIND;
3449 if (ld_tracing != NULL)
3450 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS;
3452 return (dlopen_object(name, fd, obj_main, lo_flags,
3453 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3457 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3462 if (obj->refcount == 0)
3463 unload_object(obj, lockstate);
3467 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3468 int mode, RtldLockState *lockstate)
3470 Obj_Entry *old_obj_tail;
3473 RtldLockState mlockstate;
3476 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x",
3477 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" :
3478 refobj->path, lo_flags, mode);
3479 objlist_init(&initlist);
3481 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3482 wlock_acquire(rtld_bind_lock, &mlockstate);
3483 lockstate = &mlockstate;
3485 GDB_STATE(RT_ADD,NULL);
3487 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
3489 if (name == NULL && fd == -1) {
3493 obj = load_object(name, fd, refobj, lo_flags);
3498 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3499 objlist_push_tail(&list_global, obj);
3500 if (globallist_next(old_obj_tail) != NULL) {
3501 /* We loaded something new. */
3502 assert(globallist_next(old_obj_tail) == obj);
3503 if ((lo_flags & RTLD_LO_DEEPBIND) != 0)
3504 obj->symbolic = true;
3506 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 &&
3507 obj->static_tls && !allocate_tls_offset(obj)) {
3508 _rtld_error("%s: No space available "
3509 "for static Thread Local Storage", obj->path);
3513 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN |
3514 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE));
3518 result = rtld_verify_versions(&obj->dagmembers);
3519 if (result != -1 && ld_tracing)
3521 if (result == -1 || relocate_object_dag(obj,
3522 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3523 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3525 dlopen_cleanup(obj, lockstate);
3527 } else if (lo_flags & RTLD_LO_EARLY) {
3529 * Do not call the init functions for early loaded
3530 * filtees. The image is still not initialized enough
3533 * Our object is found by the global object list and
3534 * will be ordered among all init calls done right
3535 * before transferring control to main.
3538 /* Make list of init functions to call. */
3539 initlist_add_objects(obj, obj, &initlist);
3542 * Process all no_delete or global objects here, given
3543 * them own DAGs to prevent their dependencies from being
3544 * unloaded. This has to be done after we have loaded all
3545 * of the dependencies, so that we do not miss any.
3551 * Bump the reference counts for objects on this DAG. If
3552 * this is the first dlopen() call for the object that was
3553 * already loaded as a dependency, initialize the dag
3559 if ((lo_flags & RTLD_LO_TRACE) != 0)
3562 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3563 obj->z_nodelete) && !obj->ref_nodel) {
3564 dbg("obj %s nodelete", obj->path);
3566 obj->z_nodelete = obj->ref_nodel = true;
3570 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3572 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3574 if ((lo_flags & RTLD_LO_EARLY) == 0) {
3575 map_stacks_exec(lockstate);
3577 distribute_static_tls(&initlist, lockstate);
3580 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3581 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3583 objlist_clear(&initlist);
3584 dlopen_cleanup(obj, lockstate);
3585 if (lockstate == &mlockstate)
3586 lock_release(rtld_bind_lock, lockstate);
3590 if (!(lo_flags & RTLD_LO_EARLY)) {
3591 /* Call the init functions. */
3592 objlist_call_init(&initlist, lockstate);
3594 objlist_clear(&initlist);
3595 if (lockstate == &mlockstate)
3596 lock_release(rtld_bind_lock, lockstate);
3599 trace_loaded_objects(obj);
3600 if (lockstate == &mlockstate)
3601 lock_release(rtld_bind_lock, lockstate);
3606 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3610 const Obj_Entry *obj, *defobj;
3613 RtldLockState lockstate;
3620 symlook_init(&req, name);
3622 req.flags = flags | SYMLOOK_IN_PLT;
3623 req.lockstate = &lockstate;
3625 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3626 rlock_acquire(rtld_bind_lock, &lockstate);
3627 if (sigsetjmp(lockstate.env, 0) != 0)
3628 lock_upgrade(rtld_bind_lock, &lockstate);
3629 if (handle == NULL || handle == RTLD_NEXT ||
3630 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3632 if ((obj = obj_from_addr(retaddr)) == NULL) {
3633 _rtld_error("Cannot determine caller's shared object");
3634 lock_release(rtld_bind_lock, &lockstate);
3635 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3638 if (handle == NULL) { /* Just the caller's shared object. */
3639 res = symlook_obj(&req, obj);
3642 defobj = req.defobj_out;
3644 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3645 handle == RTLD_SELF) { /* ... caller included */
3646 if (handle == RTLD_NEXT)
3647 obj = globallist_next(obj);
3648 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3651 res = symlook_obj(&req, obj);
3654 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3656 defobj = req.defobj_out;
3657 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3663 * Search the dynamic linker itself, and possibly resolve the
3664 * symbol from there. This is how the application links to
3665 * dynamic linker services such as dlopen.
3667 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3668 res = symlook_obj(&req, &obj_rtld);
3671 defobj = req.defobj_out;
3675 assert(handle == RTLD_DEFAULT);
3676 res = symlook_default(&req, obj);
3678 defobj = req.defobj_out;
3683 if ((obj = dlcheck(handle)) == NULL) {
3684 lock_release(rtld_bind_lock, &lockstate);
3685 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3689 donelist_init(&donelist);
3690 if (obj->mainprog) {
3691 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3692 res = symlook_global(&req, &donelist);
3695 defobj = req.defobj_out;
3698 * Search the dynamic linker itself, and possibly resolve the
3699 * symbol from there. This is how the application links to
3700 * dynamic linker services such as dlopen.
3702 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3703 res = symlook_obj(&req, &obj_rtld);
3706 defobj = req.defobj_out;
3711 /* Search the whole DAG rooted at the given object. */
3712 res = symlook_list(&req, &obj->dagmembers, &donelist);
3715 defobj = req.defobj_out;
3721 lock_release(rtld_bind_lock, &lockstate);
3724 * The value required by the caller is derived from the value
3725 * of the symbol. this is simply the relocated value of the
3728 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3729 sym = make_function_pointer(def, defobj);
3730 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3731 sym = rtld_resolve_ifunc(defobj, def);
3732 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3733 ti.ti_module = defobj->tlsindex;
3734 ti.ti_offset = def->st_value;
3735 sym = __tls_get_addr(&ti);
3737 sym = defobj->relocbase + def->st_value;
3738 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3742 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
3743 ve != NULL ? ve->name : "");
3744 lock_release(rtld_bind_lock, &lockstate);
3745 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3750 dlsym(void *handle, const char *name)
3752 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3757 dlfunc(void *handle, const char *name)
3764 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3770 dlvsym(void *handle, const char *name, const char *version)
3774 ventry.name = version;
3776 ventry.hash = elf_hash(version);
3778 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3783 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3785 const Obj_Entry *obj;
3786 RtldLockState lockstate;
3788 rlock_acquire(rtld_bind_lock, &lockstate);
3789 obj = obj_from_addr(addr);
3791 _rtld_error("No shared object contains address");
3792 lock_release(rtld_bind_lock, &lockstate);
3795 rtld_fill_dl_phdr_info(obj, phdr_info);
3796 lock_release(rtld_bind_lock, &lockstate);
3801 dladdr(const void *addr, Dl_info *info)
3803 const Obj_Entry *obj;
3806 unsigned long symoffset;
3807 RtldLockState lockstate;
3809 rlock_acquire(rtld_bind_lock, &lockstate);
3810 obj = obj_from_addr(addr);
3812 _rtld_error("No shared object contains address");
3813 lock_release(rtld_bind_lock, &lockstate);
3816 info->dli_fname = obj->path;
3817 info->dli_fbase = obj->mapbase;
3818 info->dli_saddr = (void *)0;
3819 info->dli_sname = NULL;
3822 * Walk the symbol list looking for the symbol whose address is
3823 * closest to the address sent in.
3825 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3826 def = obj->symtab + symoffset;
3829 * For skip the symbol if st_shndx is either SHN_UNDEF or
3832 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3836 * If the symbol is greater than the specified address, or if it
3837 * is further away from addr than the current nearest symbol,
3840 symbol_addr = obj->relocbase + def->st_value;
3841 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3844 /* Update our idea of the nearest symbol. */
3845 info->dli_sname = obj->strtab + def->st_name;
3846 info->dli_saddr = symbol_addr;
3849 if (info->dli_saddr == addr)
3852 lock_release(rtld_bind_lock, &lockstate);
3857 dlinfo(void *handle, int request, void *p)
3859 const Obj_Entry *obj;
3860 RtldLockState lockstate;
3863 rlock_acquire(rtld_bind_lock, &lockstate);
3865 if (handle == NULL || handle == RTLD_SELF) {
3868 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3869 if ((obj = obj_from_addr(retaddr)) == NULL)
3870 _rtld_error("Cannot determine caller's shared object");
3872 obj = dlcheck(handle);
3875 lock_release(rtld_bind_lock, &lockstate);
3881 case RTLD_DI_LINKMAP:
3882 *((struct link_map const **)p) = &obj->linkmap;
3884 case RTLD_DI_ORIGIN:
3885 error = rtld_dirname(obj->path, p);
3888 case RTLD_DI_SERINFOSIZE:
3889 case RTLD_DI_SERINFO:
3890 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3894 _rtld_error("Invalid request %d passed to dlinfo()", request);
3898 lock_release(rtld_bind_lock, &lockstate);
3904 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3907 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3908 phdr_info->dlpi_name = obj->path;
3909 phdr_info->dlpi_phdr = obj->phdr;
3910 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3911 phdr_info->dlpi_tls_modid = obj->tlsindex;
3912 phdr_info->dlpi_tls_data = obj->tlsinit;
3913 phdr_info->dlpi_adds = obj_loads;
3914 phdr_info->dlpi_subs = obj_loads - obj_count;
3918 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3920 struct dl_phdr_info phdr_info;
3921 Obj_Entry *obj, marker;
3922 RtldLockState bind_lockstate, phdr_lockstate;
3925 init_marker(&marker);
3928 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3929 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3930 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
3931 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
3932 rtld_fill_dl_phdr_info(obj, &phdr_info);
3934 lock_release(rtld_bind_lock, &bind_lockstate);
3936 error = callback(&phdr_info, sizeof phdr_info, param);
3938 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3940 obj = globallist_next(&marker);
3941 TAILQ_REMOVE(&obj_list, &marker, next);
3943 lock_release(rtld_bind_lock, &bind_lockstate);
3944 lock_release(rtld_phdr_lock, &phdr_lockstate);
3950 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3951 lock_release(rtld_bind_lock, &bind_lockstate);
3952 error = callback(&phdr_info, sizeof(phdr_info), param);
3954 lock_release(rtld_phdr_lock, &phdr_lockstate);
3959 fill_search_info(const char *dir, size_t dirlen, void *param)
3961 struct fill_search_info_args *arg;
3965 if (arg->request == RTLD_DI_SERINFOSIZE) {
3966 arg->serinfo->dls_cnt ++;
3967 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3969 struct dl_serpath *s_entry;
3971 s_entry = arg->serpath;
3972 s_entry->dls_name = arg->strspace;
3973 s_entry->dls_flags = arg->flags;
3975 strncpy(arg->strspace, dir, dirlen);
3976 arg->strspace[dirlen] = '\0';
3978 arg->strspace += dirlen + 1;
3986 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3988 struct dl_serinfo _info;
3989 struct fill_search_info_args args;
3991 args.request = RTLD_DI_SERINFOSIZE;
3992 args.serinfo = &_info;
3994 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3997 path_enumerate(obj->rpath, fill_search_info, NULL, &args);
3998 path_enumerate(ld_library_path, fill_search_info, NULL, &args);
3999 path_enumerate(obj->runpath, fill_search_info, NULL, &args);
4000 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args);
4001 if (!obj->z_nodeflib)
4002 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args);
4005 if (request == RTLD_DI_SERINFOSIZE) {
4006 info->dls_size = _info.dls_size;
4007 info->dls_cnt = _info.dls_cnt;
4011 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
4012 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
4016 args.request = RTLD_DI_SERINFO;
4017 args.serinfo = info;
4018 args.serpath = &info->dls_serpath[0];
4019 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
4021 args.flags = LA_SER_RUNPATH;
4022 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL)
4025 args.flags = LA_SER_LIBPATH;
4026 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL)
4029 args.flags = LA_SER_RUNPATH;
4030 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL)
4033 args.flags = LA_SER_CONFIG;
4034 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args)
4038 args.flags = LA_SER_DEFAULT;
4039 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path,
4040 fill_search_info, NULL, &args) != NULL)
4046 rtld_dirname(const char *path, char *bname)
4050 /* Empty or NULL string gets treated as "." */
4051 if (path == NULL || *path == '\0') {
4057 /* Strip trailing slashes */
4058 endp = path + strlen(path) - 1;
4059 while (endp > path && *endp == '/')
4062 /* Find the start of the dir */
4063 while (endp > path && *endp != '/')
4066 /* Either the dir is "/" or there are no slashes */
4068 bname[0] = *endp == '/' ? '/' : '.';
4074 } while (endp > path && *endp == '/');
4077 if (endp - path + 2 > PATH_MAX)
4079 _rtld_error("Filename is too long: %s", path);
4083 strncpy(bname, path, endp - path + 1);
4084 bname[endp - path + 1] = '\0';
4089 rtld_dirname_abs(const char *path, char *base)
4093 if (realpath(path, base) == NULL) {
4094 _rtld_error("realpath \"%s\" failed (%s)", path,
4095 rtld_strerror(errno));
4098 dbg("%s -> %s", path, base);
4099 last = strrchr(base, '/');
4101 _rtld_error("non-abs result from realpath \"%s\"", path);
4110 linkmap_add(Obj_Entry *obj)
4112 struct link_map *l, *prev;
4115 l->l_name = obj->path;
4116 l->l_base = obj->mapbase;
4117 l->l_ld = obj->dynamic;
4118 l->l_addr = obj->relocbase;
4120 if (r_debug.r_map == NULL) {
4126 * Scan to the end of the list, but not past the entry for the
4127 * dynamic linker, which we want to keep at the very end.
4129 for (prev = r_debug.r_map;
4130 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
4131 prev = prev->l_next)
4134 /* Link in the new entry. */
4136 l->l_next = prev->l_next;
4137 if (l->l_next != NULL)
4138 l->l_next->l_prev = l;
4143 linkmap_delete(Obj_Entry *obj)
4148 if (l->l_prev == NULL) {
4149 if ((r_debug.r_map = l->l_next) != NULL)
4150 l->l_next->l_prev = NULL;
4154 if ((l->l_prev->l_next = l->l_next) != NULL)
4155 l->l_next->l_prev = l->l_prev;
4159 * Function for the debugger to set a breakpoint on to gain control.
4161 * The two parameters allow the debugger to easily find and determine
4162 * what the runtime loader is doing and to whom it is doing it.
4164 * When the loadhook trap is hit (r_debug_state, set at program
4165 * initialization), the arguments can be found on the stack:
4167 * +8 struct link_map *m
4168 * +4 struct r_debug *rd
4172 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused)
4175 * The following is a hack to force the compiler to emit calls to
4176 * this function, even when optimizing. If the function is empty,
4177 * the compiler is not obliged to emit any code for calls to it,
4178 * even when marked __noinline. However, gdb depends on those
4181 __compiler_membar();
4185 * A function called after init routines have completed. This can be used to
4186 * break before a program's entry routine is called, and can be used when
4187 * main is not available in the symbol table.
4190 _r_debug_postinit(struct link_map *m __unused)
4193 /* See r_debug_state(). */
4194 __compiler_membar();
4198 release_object(Obj_Entry *obj)
4201 if (obj->holdcount > 0) {
4202 obj->unholdfree = true;
4205 munmap(obj->mapbase, obj->mapsize);
4206 linkmap_delete(obj);
4211 * Get address of the pointer variable in the main program.
4212 * Prefer non-weak symbol over the weak one.
4214 static const void **
4215 get_program_var_addr(const char *name, RtldLockState *lockstate)
4220 symlook_init(&req, name);
4221 req.lockstate = lockstate;
4222 donelist_init(&donelist);
4223 if (symlook_global(&req, &donelist) != 0)
4225 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4226 return ((const void **)make_function_pointer(req.sym_out,
4228 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4229 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
4231 return ((const void **)(req.defobj_out->relocbase +
4232 req.sym_out->st_value));
4236 * Set a pointer variable in the main program to the given value. This
4237 * is used to set key variables such as "environ" before any of the
4238 * init functions are called.
4241 set_program_var(const char *name, const void *value)
4245 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4246 dbg("\"%s\": *%p <-- %p", name, addr, value);
4252 * Search the global objects, including dependencies and main object,
4253 * for the given symbol.
4256 symlook_global(SymLook *req, DoneList *donelist)
4259 const Objlist_Entry *elm;
4262 symlook_init_from_req(&req1, req);
4264 /* Search all objects loaded at program start up. */
4265 if (req->defobj_out == NULL ||
4266 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4267 res = symlook_list(&req1, &list_main, donelist);
4268 if (res == 0 && (req->defobj_out == NULL ||
4269 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4270 req->sym_out = req1.sym_out;
4271 req->defobj_out = req1.defobj_out;
4272 assert(req->defobj_out != NULL);
4276 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4277 STAILQ_FOREACH(elm, &list_global, link) {
4278 if (req->defobj_out != NULL &&
4279 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4281 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4282 if (res == 0 && (req->defobj_out == NULL ||
4283 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4284 req->sym_out = req1.sym_out;
4285 req->defobj_out = req1.defobj_out;
4286 assert(req->defobj_out != NULL);
4290 return (req->sym_out != NULL ? 0 : ESRCH);
4294 * Given a symbol name in a referencing object, find the corresponding
4295 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4296 * no definition was found. Returns a pointer to the Obj_Entry of the
4297 * defining object via the reference parameter DEFOBJ_OUT.
4300 symlook_default(SymLook *req, const Obj_Entry *refobj)
4303 const Objlist_Entry *elm;
4307 donelist_init(&donelist);
4308 symlook_init_from_req(&req1, req);
4311 * Look first in the referencing object if linked symbolically,
4312 * and similarly handle protected symbols.
4314 res = symlook_obj(&req1, refobj);
4315 if (res == 0 && (refobj->symbolic ||
4316 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) {
4317 req->sym_out = req1.sym_out;
4318 req->defobj_out = req1.defobj_out;
4319 assert(req->defobj_out != NULL);
4321 if (refobj->symbolic || req->defobj_out != NULL)
4322 donelist_check(&donelist, refobj);
4324 symlook_global(req, &donelist);
4326 /* Search all dlopened DAGs containing the referencing object. */
4327 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4328 if (req->sym_out != NULL &&
4329 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4331 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4332 if (res == 0 && (req->sym_out == NULL ||
4333 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4334 req->sym_out = req1.sym_out;
4335 req->defobj_out = req1.defobj_out;
4336 assert(req->defobj_out != NULL);
4341 * Search the dynamic linker itself, and possibly resolve the
4342 * symbol from there. This is how the application links to
4343 * dynamic linker services such as dlopen.
4345 if (req->sym_out == NULL ||
4346 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4347 res = symlook_obj(&req1, &obj_rtld);
4349 req->sym_out = req1.sym_out;
4350 req->defobj_out = req1.defobj_out;
4351 assert(req->defobj_out != NULL);
4355 return (req->sym_out != NULL ? 0 : ESRCH);
4359 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4362 const Obj_Entry *defobj;
4363 const Objlist_Entry *elm;
4369 STAILQ_FOREACH(elm, objlist, link) {
4370 if (donelist_check(dlp, elm->obj))
4372 symlook_init_from_req(&req1, req);
4373 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4374 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4376 defobj = req1.defobj_out;
4377 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4384 req->defobj_out = defobj;
4391 * Search the chain of DAGS cointed to by the given Needed_Entry
4392 * for a symbol of the given name. Each DAG is scanned completely
4393 * before advancing to the next one. Returns a pointer to the symbol,
4394 * or NULL if no definition was found.
4397 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4400 const Needed_Entry *n;
4401 const Obj_Entry *defobj;
4407 symlook_init_from_req(&req1, req);
4408 for (n = needed; n != NULL; n = n->next) {
4409 if (n->obj == NULL ||
4410 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
4412 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4414 defobj = req1.defobj_out;
4415 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4421 req->defobj_out = defobj;
4428 * Search the symbol table of a single shared object for a symbol of
4429 * the given name and version, if requested. Returns a pointer to the
4430 * symbol, or NULL if no definition was found. If the object is
4431 * filter, return filtered symbol from filtee.
4433 * The symbol's hash value is passed in for efficiency reasons; that
4434 * eliminates many recomputations of the hash value.
4437 symlook_obj(SymLook *req, const Obj_Entry *obj)
4441 int flags, res, mres;
4444 * If there is at least one valid hash at this point, we prefer to
4445 * use the faster GNU version if available.
4447 if (obj->valid_hash_gnu)
4448 mres = symlook_obj1_gnu(req, obj);
4449 else if (obj->valid_hash_sysv)
4450 mres = symlook_obj1_sysv(req, obj);
4455 if (obj->needed_filtees != NULL) {
4456 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4457 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4458 donelist_init(&donelist);
4459 symlook_init_from_req(&req1, req);
4460 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
4462 req->sym_out = req1.sym_out;
4463 req->defobj_out = req1.defobj_out;
4467 if (obj->needed_aux_filtees != NULL) {
4468 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4469 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4470 donelist_init(&donelist);
4471 symlook_init_from_req(&req1, req);
4472 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
4474 req->sym_out = req1.sym_out;
4475 req->defobj_out = req1.defobj_out;
4483 /* Symbol match routine common to both hash functions */
4485 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4486 const unsigned long symnum)
4489 const Elf_Sym *symp;
4492 symp = obj->symtab + symnum;
4493 strp = obj->strtab + symp->st_name;
4495 switch (ELF_ST_TYPE(symp->st_info)) {
4501 if (symp->st_value == 0)
4505 if (symp->st_shndx != SHN_UNDEF)
4508 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4509 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4516 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4519 if (req->ventry == NULL) {
4520 if (obj->versyms != NULL) {
4521 verndx = VER_NDX(obj->versyms[symnum]);
4522 if (verndx > obj->vernum) {
4524 "%s: symbol %s references wrong version %d",
4525 obj->path, obj->strtab + symnum, verndx);
4529 * If we are not called from dlsym (i.e. this
4530 * is a normal relocation from unversioned
4531 * binary), accept the symbol immediately if
4532 * it happens to have first version after this
4533 * shared object became versioned. Otherwise,
4534 * if symbol is versioned and not hidden,
4535 * remember it. If it is the only symbol with
4536 * this name exported by the shared object, it
4537 * will be returned as a match by the calling
4538 * function. If symbol is global (verndx < 2)
4539 * accept it unconditionally.
4541 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4542 verndx == VER_NDX_GIVEN) {
4543 result->sym_out = symp;
4546 else if (verndx >= VER_NDX_GIVEN) {
4547 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4549 if (result->vsymp == NULL)
4550 result->vsymp = symp;
4556 result->sym_out = symp;
4559 if (obj->versyms == NULL) {
4560 if (object_match_name(obj, req->ventry->name)) {
4561 _rtld_error("%s: object %s should provide version %s "
4562 "for symbol %s", obj_rtld.path, obj->path,
4563 req->ventry->name, obj->strtab + symnum);
4567 verndx = VER_NDX(obj->versyms[symnum]);
4568 if (verndx > obj->vernum) {
4569 _rtld_error("%s: symbol %s references wrong version %d",
4570 obj->path, obj->strtab + symnum, verndx);
4573 if (obj->vertab[verndx].hash != req->ventry->hash ||
4574 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4576 * Version does not match. Look if this is a
4577 * global symbol and if it is not hidden. If
4578 * global symbol (verndx < 2) is available,
4579 * use it. Do not return symbol if we are
4580 * called by dlvsym, because dlvsym looks for
4581 * a specific version and default one is not
4582 * what dlvsym wants.
4584 if ((req->flags & SYMLOOK_DLSYM) ||
4585 (verndx >= VER_NDX_GIVEN) ||
4586 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4590 result->sym_out = symp;
4595 * Search for symbol using SysV hash function.
4596 * obj->buckets is known not to be NULL at this point; the test for this was
4597 * performed with the obj->valid_hash_sysv assignment.
4600 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4602 unsigned long symnum;
4603 Sym_Match_Result matchres;
4605 matchres.sym_out = NULL;
4606 matchres.vsymp = NULL;
4607 matchres.vcount = 0;
4609 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4610 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4611 if (symnum >= obj->nchains)
4612 return (ESRCH); /* Bad object */
4614 if (matched_symbol(req, obj, &matchres, symnum)) {
4615 req->sym_out = matchres.sym_out;
4616 req->defobj_out = obj;
4620 if (matchres.vcount == 1) {
4621 req->sym_out = matchres.vsymp;
4622 req->defobj_out = obj;
4628 /* Search for symbol using GNU hash function */
4630 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4632 Elf_Addr bloom_word;
4633 const Elf32_Word *hashval;
4635 Sym_Match_Result matchres;
4636 unsigned int h1, h2;
4637 unsigned long symnum;
4639 matchres.sym_out = NULL;
4640 matchres.vsymp = NULL;
4641 matchres.vcount = 0;
4643 /* Pick right bitmask word from Bloom filter array */
4644 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4645 obj->maskwords_bm_gnu];
4647 /* Calculate modulus word size of gnu hash and its derivative */
4648 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4649 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4651 /* Filter out the "definitely not in set" queries */
4652 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4655 /* Locate hash chain and corresponding value element*/
4656 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4659 hashval = &obj->chain_zero_gnu[bucket];
4661 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4662 symnum = hashval - obj->chain_zero_gnu;
4663 if (matched_symbol(req, obj, &matchres, symnum)) {
4664 req->sym_out = matchres.sym_out;
4665 req->defobj_out = obj;
4669 } while ((*hashval++ & 1) == 0);
4670 if (matchres.vcount == 1) {
4671 req->sym_out = matchres.vsymp;
4672 req->defobj_out = obj;
4679 trace_loaded_objects(Obj_Entry *obj)
4681 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4684 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL)
4687 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL)
4688 fmt1 = "\t%o => %p (%x)\n";
4690 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL)
4691 fmt2 = "\t%o (%x)\n";
4693 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL"));
4695 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4696 Needed_Entry *needed;
4697 const char *name, *path;
4702 if (list_containers && obj->needed != NULL)
4703 rtld_printf("%s:\n", obj->path);
4704 for (needed = obj->needed; needed; needed = needed->next) {
4705 if (needed->obj != NULL) {
4706 if (needed->obj->traced && !list_containers)
4708 needed->obj->traced = true;
4709 path = needed->obj->path;
4713 name = obj->strtab + needed->name;
4714 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4716 fmt = is_lib ? fmt1 : fmt2;
4717 while ((c = *fmt++) != '\0') {
4743 rtld_putstr(main_local);
4746 rtld_putstr(obj_main->path);
4753 rtld_printf("%d", sodp->sod_major);
4756 rtld_printf("%d", sodp->sod_minor);
4763 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4776 * Unload a dlopened object and its dependencies from memory and from
4777 * our data structures. It is assumed that the DAG rooted in the
4778 * object has already been unreferenced, and that the object has a
4779 * reference count of 0.
4782 unload_object(Obj_Entry *root, RtldLockState *lockstate)
4784 Obj_Entry marker, *obj, *next;
4786 assert(root->refcount == 0);
4789 * Pass over the DAG removing unreferenced objects from
4790 * appropriate lists.
4792 unlink_object(root);
4794 /* Unmap all objects that are no longer referenced. */
4795 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
4796 next = TAILQ_NEXT(obj, next);
4797 if (obj->marker || obj->refcount != 0)
4799 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
4800 obj->mapsize, 0, obj->path);
4801 dbg("unloading \"%s\"", obj->path);
4803 * Unlink the object now to prevent new references from
4804 * being acquired while the bind lock is dropped in
4805 * recursive dlclose() invocations.
4807 TAILQ_REMOVE(&obj_list, obj, next);
4810 if (obj->filtees_loaded) {
4812 init_marker(&marker);
4813 TAILQ_INSERT_BEFORE(next, &marker, next);
4814 unload_filtees(obj, lockstate);
4815 next = TAILQ_NEXT(&marker, next);
4816 TAILQ_REMOVE(&obj_list, &marker, next);
4818 unload_filtees(obj, lockstate);
4820 release_object(obj);
4825 unlink_object(Obj_Entry *root)
4829 if (root->refcount == 0) {
4830 /* Remove the object from the RTLD_GLOBAL list. */
4831 objlist_remove(&list_global, root);
4833 /* Remove the object from all objects' DAG lists. */
4834 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4835 objlist_remove(&elm->obj->dldags, root);
4836 if (elm->obj != root)
4837 unlink_object(elm->obj);
4843 ref_dag(Obj_Entry *root)
4847 assert(root->dag_inited);
4848 STAILQ_FOREACH(elm, &root->dagmembers, link)
4849 elm->obj->refcount++;
4853 unref_dag(Obj_Entry *root)
4857 assert(root->dag_inited);
4858 STAILQ_FOREACH(elm, &root->dagmembers, link)
4859 elm->obj->refcount--;
4863 * Common code for MD __tls_get_addr().
4865 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4867 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4869 Elf_Addr *newdtv, *dtv;
4870 RtldLockState lockstate;
4874 /* Check dtv generation in case new modules have arrived */
4875 if (dtv[0] != tls_dtv_generation) {
4876 wlock_acquire(rtld_bind_lock, &lockstate);
4877 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4879 if (to_copy > tls_max_index)
4880 to_copy = tls_max_index;
4881 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4882 newdtv[0] = tls_dtv_generation;
4883 newdtv[1] = tls_max_index;
4885 lock_release(rtld_bind_lock, &lockstate);
4886 dtv = *dtvp = newdtv;
4889 /* Dynamically allocate module TLS if necessary */
4890 if (dtv[index + 1] == 0) {
4891 /* Signal safe, wlock will block out signals. */
4892 wlock_acquire(rtld_bind_lock, &lockstate);
4893 if (!dtv[index + 1])
4894 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4895 lock_release(rtld_bind_lock, &lockstate);
4897 return ((void *)(dtv[index + 1] + offset));
4901 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4906 /* Check dtv generation in case new modules have arrived */
4907 if (__predict_true(dtv[0] == tls_dtv_generation &&
4908 dtv[index + 1] != 0))
4909 return ((void *)(dtv[index + 1] + offset));
4910 return (tls_get_addr_slow(dtvp, index, offset));
4913 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
4914 defined(__powerpc__) || defined(__riscv)
4917 * Return pointer to allocated TLS block
4920 get_tls_block_ptr(void *tcb, size_t tcbsize)
4922 size_t extra_size, post_size, pre_size, tls_block_size;
4923 size_t tls_init_align;
4925 tls_init_align = MAX(obj_main->tlsalign, 1);
4927 /* Compute fragments sizes. */
4928 extra_size = tcbsize - TLS_TCB_SIZE;
4929 post_size = calculate_tls_post_size(tls_init_align);
4930 tls_block_size = tcbsize + post_size;
4931 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4933 return ((char *)tcb - pre_size - extra_size);
4937 * Allocate Static TLS using the Variant I method.
4939 * For details on the layout, see lib/libc/gen/tls.c.
4941 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as
4942 * it is based on tls_last_offset, and TLS offsets here are really TCB
4943 * offsets, whereas libc's tls_static_space is just the executable's static
4947 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4951 Elf_Addr *dtv, **tcb;
4954 size_t extra_size, maxalign, post_size, pre_size, tls_block_size;
4955 size_t tls_init_align, tls_init_offset;
4957 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4960 assert(tcbsize >= TLS_TCB_SIZE);
4961 maxalign = MAX(tcbalign, tls_static_max_align);
4962 tls_init_align = MAX(obj_main->tlsalign, 1);
4964 /* Compute fragmets sizes. */
4965 extra_size = tcbsize - TLS_TCB_SIZE;
4966 post_size = calculate_tls_post_size(tls_init_align);
4967 tls_block_size = tcbsize + post_size;
4968 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4969 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size;
4971 /* Allocate whole TLS block */
4972 tls_block = malloc_aligned(tls_block_size, maxalign, 0);
4973 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size);
4975 if (oldtcb != NULL) {
4976 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize),
4978 free_aligned(get_tls_block_ptr(oldtcb, tcbsize));
4980 /* Adjust the DTV. */
4982 for (i = 0; i < dtv[1]; i++) {
4983 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4984 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4985 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb;
4989 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4991 dtv[0] = tls_dtv_generation;
4992 dtv[1] = tls_max_index;
4994 for (obj = globallist_curr(objs); obj != NULL;
4995 obj = globallist_next(obj)) {
4996 if (obj->tlsoffset == 0)
4998 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1);
4999 addr = (Elf_Addr)tcb + obj->tlsoffset;
5000 if (tls_init_offset > 0)
5001 memset((void *)addr, 0, tls_init_offset);
5002 if (obj->tlsinitsize > 0) {
5003 memcpy((void *)(addr + tls_init_offset), obj->tlsinit,
5006 if (obj->tlssize > obj->tlsinitsize) {
5007 memset((void *)(addr + tls_init_offset + obj->tlsinitsize),
5008 0, obj->tlssize - obj->tlsinitsize - tls_init_offset);
5010 dtv[obj->tlsindex + 1] = addr;
5018 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
5021 Elf_Addr tlsstart, tlsend;
5023 size_t dtvsize, i, tls_init_align;
5025 assert(tcbsize >= TLS_TCB_SIZE);
5026 tls_init_align = MAX(obj_main->tlsalign, 1);
5028 /* Compute fragments sizes. */
5029 post_size = calculate_tls_post_size(tls_init_align);
5031 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size;
5032 tlsend = (Elf_Addr)tcb + tls_static_space;
5034 dtv = *(Elf_Addr **)tcb;
5036 for (i = 0; i < dtvsize; i++) {
5037 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
5038 free((void*)dtv[i+2]);
5042 free_aligned(get_tls_block_ptr(tcb, tcbsize));
5047 #if defined(__i386__) || defined(__amd64__)
5050 * Allocate Static TLS using the Variant II method.
5053 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
5056 size_t size, ralign;
5058 Elf_Addr *dtv, *olddtv;
5059 Elf_Addr segbase, oldsegbase, addr;
5063 if (tls_static_max_align > ralign)
5064 ralign = tls_static_max_align;
5065 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign);
5067 assert(tcbsize >= 2*sizeof(Elf_Addr));
5068 tls = malloc_aligned(size, ralign, 0 /* XXX */);
5069 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
5071 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign));
5072 ((Elf_Addr*)segbase)[0] = segbase;
5073 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
5075 dtv[0] = tls_dtv_generation;
5076 dtv[1] = tls_max_index;
5080 * Copy the static TLS block over whole.
5082 oldsegbase = (Elf_Addr) oldtls;
5083 memcpy((void *)(segbase - tls_static_space),
5084 (const void *)(oldsegbase - tls_static_space),
5088 * If any dynamic TLS blocks have been created tls_get_addr(),
5091 olddtv = ((Elf_Addr**)oldsegbase)[1];
5092 for (i = 0; i < olddtv[1]; i++) {
5093 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
5094 dtv[i+2] = olddtv[i+2];
5100 * We assume that this block was the one we created with
5101 * allocate_initial_tls().
5103 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
5105 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
5106 if (obj->marker || obj->tlsoffset == 0)
5108 addr = segbase - obj->tlsoffset;
5109 memset((void*)(addr + obj->tlsinitsize),
5110 0, obj->tlssize - obj->tlsinitsize);
5112 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
5113 obj->static_tls_copied = true;
5115 dtv[obj->tlsindex + 1] = addr;
5119 return (void*) segbase;
5123 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign)
5126 size_t size, ralign;
5128 Elf_Addr tlsstart, tlsend;
5131 * Figure out the size of the initial TLS block so that we can
5132 * find stuff which ___tls_get_addr() allocated dynamically.
5135 if (tls_static_max_align > ralign)
5136 ralign = tls_static_max_align;
5137 size = roundup(tls_static_space, ralign);
5139 dtv = ((Elf_Addr**)tls)[1];
5141 tlsend = (Elf_Addr) tls;
5142 tlsstart = tlsend - size;
5143 for (i = 0; i < dtvsize; i++) {
5144 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
5145 free_aligned((void *)dtv[i + 2]);
5149 free_aligned((void *)tlsstart);
5156 * Allocate TLS block for module with given index.
5159 allocate_module_tls(int index)
5164 TAILQ_FOREACH(obj, &obj_list, next) {
5167 if (obj->tlsindex == index)
5171 _rtld_error("Can't find module with TLS index %d", index);
5175 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset);
5176 memcpy(p, obj->tlsinit, obj->tlsinitsize);
5177 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
5182 allocate_tls_offset(Obj_Entry *obj)
5189 if (obj->tlssize == 0) {
5190 obj->tls_done = true;
5194 if (tls_last_offset == 0)
5195 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign,
5198 off = calculate_tls_offset(tls_last_offset, tls_last_size,
5199 obj->tlssize, obj->tlsalign, obj->tlspoffset);
5202 * If we have already fixed the size of the static TLS block, we
5203 * must stay within that size. When allocating the static TLS, we
5204 * leave a small amount of space spare to be used for dynamically
5205 * loading modules which use static TLS.
5207 if (tls_static_space != 0) {
5208 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
5210 } else if (obj->tlsalign > tls_static_max_align) {
5211 tls_static_max_align = obj->tlsalign;
5214 tls_last_offset = obj->tlsoffset = off;
5215 tls_last_size = obj->tlssize;
5216 obj->tls_done = true;
5222 free_tls_offset(Obj_Entry *obj)
5226 * If we were the last thing to allocate out of the static TLS
5227 * block, we give our space back to the 'allocator'. This is a
5228 * simplistic workaround to allow libGL.so.1 to be loaded and
5229 * unloaded multiple times.
5231 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
5232 == calculate_tls_end(tls_last_offset, tls_last_size)) {
5233 tls_last_offset -= obj->tlssize;
5239 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
5242 RtldLockState lockstate;
5244 wlock_acquire(rtld_bind_lock, &lockstate);
5245 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
5247 lock_release(rtld_bind_lock, &lockstate);
5252 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
5254 RtldLockState lockstate;
5256 wlock_acquire(rtld_bind_lock, &lockstate);
5257 free_tls(tcb, tcbsize, tcbalign);
5258 lock_release(rtld_bind_lock, &lockstate);
5262 object_add_name(Obj_Entry *obj, const char *name)
5268 entry = malloc(sizeof(Name_Entry) + len);
5270 if (entry != NULL) {
5271 strcpy(entry->name, name);
5272 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5277 object_match_name(const Obj_Entry *obj, const char *name)
5281 STAILQ_FOREACH(entry, &obj->names, link) {
5282 if (strcmp(name, entry->name) == 0)
5289 locate_dependency(const Obj_Entry *obj, const char *name)
5291 const Objlist_Entry *entry;
5292 const Needed_Entry *needed;
5294 STAILQ_FOREACH(entry, &list_main, link) {
5295 if (object_match_name(entry->obj, name))
5299 for (needed = obj->needed; needed != NULL; needed = needed->next) {
5300 if (strcmp(obj->strtab + needed->name, name) == 0 ||
5301 (needed->obj != NULL && object_match_name(needed->obj, name))) {
5303 * If there is DT_NEEDED for the name we are looking for,
5304 * we are all set. Note that object might not be found if
5305 * dependency was not loaded yet, so the function can
5306 * return NULL here. This is expected and handled
5307 * properly by the caller.
5309 return (needed->obj);
5312 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
5318 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
5319 const Elf_Vernaux *vna)
5321 const Elf_Verdef *vd;
5322 const char *vername;
5324 vername = refobj->strtab + vna->vna_name;
5325 vd = depobj->verdef;
5327 _rtld_error("%s: version %s required by %s not defined",
5328 depobj->path, vername, refobj->path);
5332 if (vd->vd_version != VER_DEF_CURRENT) {
5333 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5334 depobj->path, vd->vd_version);
5337 if (vna->vna_hash == vd->vd_hash) {
5338 const Elf_Verdaux *aux = (const Elf_Verdaux *)
5339 ((const char *)vd + vd->vd_aux);
5340 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
5343 if (vd->vd_next == 0)
5345 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5347 if (vna->vna_flags & VER_FLG_WEAK)
5349 _rtld_error("%s: version %s required by %s not found",
5350 depobj->path, vername, refobj->path);
5355 rtld_verify_object_versions(Obj_Entry *obj)
5357 const Elf_Verneed *vn;
5358 const Elf_Verdef *vd;
5359 const Elf_Verdaux *vda;
5360 const Elf_Vernaux *vna;
5361 const Obj_Entry *depobj;
5362 int maxvernum, vernum;
5364 if (obj->ver_checked)
5366 obj->ver_checked = true;
5370 * Walk over defined and required version records and figure out
5371 * max index used by any of them. Do very basic sanity checking
5375 while (vn != NULL) {
5376 if (vn->vn_version != VER_NEED_CURRENT) {
5377 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
5378 obj->path, vn->vn_version);
5381 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5383 vernum = VER_NEED_IDX(vna->vna_other);
5384 if (vernum > maxvernum)
5386 if (vna->vna_next == 0)
5388 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5390 if (vn->vn_next == 0)
5392 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5396 while (vd != NULL) {
5397 if (vd->vd_version != VER_DEF_CURRENT) {
5398 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5399 obj->path, vd->vd_version);
5402 vernum = VER_DEF_IDX(vd->vd_ndx);
5403 if (vernum > maxvernum)
5405 if (vd->vd_next == 0)
5407 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5414 * Store version information in array indexable by version index.
5415 * Verify that object version requirements are satisfied along the
5418 obj->vernum = maxvernum + 1;
5419 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
5422 while (vd != NULL) {
5423 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
5424 vernum = VER_DEF_IDX(vd->vd_ndx);
5425 assert(vernum <= maxvernum);
5426 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux);
5427 obj->vertab[vernum].hash = vd->vd_hash;
5428 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
5429 obj->vertab[vernum].file = NULL;
5430 obj->vertab[vernum].flags = 0;
5432 if (vd->vd_next == 0)
5434 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5438 while (vn != NULL) {
5439 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
5442 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5444 if (check_object_provided_version(obj, depobj, vna))
5446 vernum = VER_NEED_IDX(vna->vna_other);
5447 assert(vernum <= maxvernum);
5448 obj->vertab[vernum].hash = vna->vna_hash;
5449 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
5450 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
5451 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
5452 VER_INFO_HIDDEN : 0;
5453 if (vna->vna_next == 0)
5455 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5457 if (vn->vn_next == 0)
5459 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5465 rtld_verify_versions(const Objlist *objlist)
5467 Objlist_Entry *entry;
5471 STAILQ_FOREACH(entry, objlist, link) {
5473 * Skip dummy objects or objects that have their version requirements
5476 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
5478 if (rtld_verify_object_versions(entry->obj) == -1) {
5480 if (ld_tracing == NULL)
5484 if (rc == 0 || ld_tracing != NULL)
5485 rc = rtld_verify_object_versions(&obj_rtld);
5490 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
5495 vernum = VER_NDX(obj->versyms[symnum]);
5496 if (vernum >= obj->vernum) {
5497 _rtld_error("%s: symbol %s has wrong verneed value %d",
5498 obj->path, obj->strtab + symnum, vernum);
5499 } else if (obj->vertab[vernum].hash != 0) {
5500 return &obj->vertab[vernum];
5507 _rtld_get_stack_prot(void)
5510 return (stack_prot);
5514 _rtld_is_dlopened(void *arg)
5517 RtldLockState lockstate;
5520 rlock_acquire(rtld_bind_lock, &lockstate);
5523 obj = obj_from_addr(arg);
5525 _rtld_error("No shared object contains address");
5526 lock_release(rtld_bind_lock, &lockstate);
5529 res = obj->dlopened ? 1 : 0;
5530 lock_release(rtld_bind_lock, &lockstate);
5535 obj_remap_relro(Obj_Entry *obj, int prot)
5538 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size,
5540 _rtld_error("%s: Cannot set relro protection to %#x: %s",
5541 obj->path, prot, rtld_strerror(errno));
5548 obj_disable_relro(Obj_Entry *obj)
5551 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE));
5555 obj_enforce_relro(Obj_Entry *obj)
5558 return (obj_remap_relro(obj, PROT_READ));
5562 map_stacks_exec(RtldLockState *lockstate)
5564 void (*thr_map_stacks_exec)(void);
5566 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
5568 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
5569 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
5570 if (thr_map_stacks_exec != NULL) {
5571 stack_prot |= PROT_EXEC;
5572 thr_map_stacks_exec();
5577 distribute_static_tls(Objlist *list, RtldLockState *lockstate)
5581 void (*distrib)(size_t, void *, size_t, size_t);
5583 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t)
5584 get_program_var_addr("__pthread_distribute_static_tls", lockstate);
5585 if (distrib == NULL)
5587 STAILQ_FOREACH(elm, list, link) {
5589 if (obj->marker || !obj->tls_done || obj->static_tls_copied)
5591 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize,
5593 obj->static_tls_copied = true;
5598 symlook_init(SymLook *dst, const char *name)
5601 bzero(dst, sizeof(*dst));
5603 dst->hash = elf_hash(name);
5604 dst->hash_gnu = gnu_hash(name);
5608 symlook_init_from_req(SymLook *dst, const SymLook *src)
5611 dst->name = src->name;
5612 dst->hash = src->hash;
5613 dst->hash_gnu = src->hash_gnu;
5614 dst->ventry = src->ventry;
5615 dst->flags = src->flags;
5616 dst->defobj_out = NULL;
5617 dst->sym_out = NULL;
5618 dst->lockstate = src->lockstate;
5622 open_binary_fd(const char *argv0, bool search_in_path,
5623 const char **binpath_res)
5625 char *binpath, *pathenv, *pe, *res1;
5631 if (search_in_path && strchr(argv0, '/') == NULL) {
5632 binpath = xmalloc(PATH_MAX);
5633 pathenv = getenv("PATH");
5634 if (pathenv == NULL) {
5635 _rtld_error("-p and no PATH environment variable");
5638 pathenv = strdup(pathenv);
5639 if (pathenv == NULL) {
5640 _rtld_error("Cannot allocate memory");
5645 while ((pe = strsep(&pathenv, ":")) != NULL) {
5646 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX)
5648 if (binpath[0] != '\0' &&
5649 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX)
5651 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX)
5653 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
5654 if (fd != -1 || errno != ENOENT) {
5661 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
5666 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno));
5669 if (res != NULL && res[0] != '/') {
5670 res1 = xmalloc(PATH_MAX);
5671 if (realpath(res, res1) != NULL) {
5673 free(__DECONST(char *, res));
5684 * Parse a set of command-line arguments.
5687 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp,
5693 int arglen, fd, i, j, mib[2];
5695 bool seen_b, seen_f;
5697 dbg("Parsing command-line arguments");
5700 seen_b = seen_f = false;
5702 for (i = 1; i < argc; i++ ) {
5704 dbg("argv[%d]: '%s'", i, arg);
5707 * rtld arguments end with an explicit "--" or with the first
5708 * non-prefixed argument.
5710 if (strcmp(arg, "--") == 0) {
5718 * All other arguments are single-character options that can
5719 * be combined, so we need to search through `arg` for them.
5721 arglen = strlen(arg);
5722 for (j = 1; j < arglen; j++) {
5725 print_usage(argv[0]);
5727 } else if (opt == 'b') {
5729 _rtld_error("Both -b and -f specified");
5736 } else if (opt == 'f') {
5738 _rtld_error("Both -b and -f specified");
5743 * -f XX can be used to specify a
5744 * descriptor for the binary named at
5745 * the command line (i.e., the later
5746 * argument will specify the process
5747 * name but the descriptor is what
5748 * will actually be executed).
5750 * -f must be the last option in, e.g., -abcf.
5752 if (j != arglen - 1) {
5753 _rtld_error("Invalid options: %s", arg);
5757 fd = parse_integer(argv[i]);
5760 "Invalid file descriptor: '%s'",
5767 } else if (opt == 'p') {
5769 } else if (opt == 'v') {
5772 mib[1] = HW_MACHINE;
5773 sz = sizeof(machine);
5774 sysctl(mib, nitems(mib), machine, &sz, NULL, 0);
5776 "FreeBSD ld-elf.so.1 %s\n"
5777 "FreeBSD_version %d\n"
5778 "Default lib path %s\n"
5783 __FreeBSD_version, ld_standard_library_path,
5784 ld_env_prefix, ld_elf_hints_default,
5785 ld_path_libmap_conf);
5788 _rtld_error("Invalid argument: '%s'", arg);
5789 print_usage(argv[0]);
5801 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
5804 parse_integer(const char *str)
5806 static const int RADIX = 10; /* XXXJA: possibly support hex? */
5813 for (c = *str; c != '\0'; c = *++str) {
5814 if (c < '0' || c > '9')
5821 /* Make sure we actually parsed something. */
5828 print_usage(const char *argv0)
5832 "Usage: %s [-h] [-b <exe>] [-f <FD>] [-p] [--] <binary> [<args>]\n"
5835 " -h Display this help message\n"
5836 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n"
5837 " -f <FD> Execute <FD> instead of searching for <binary>\n"
5838 " -p Search in PATH for named binary\n"
5839 " -v Display identification information\n"
5840 " -- End of RTLD options\n"
5841 " <binary> Name of process to execute\n"
5842 " <args> Arguments to the executed process\n", argv0);
5846 * Overrides for libc_pic-provided functions.
5850 __getosreldate(void)
5860 oid[1] = KERN_OSRELDATE;
5862 len = sizeof(osrel);
5863 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5864 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5869 rtld_strerror(int errnum)
5872 if (errnum < 0 || errnum >= sys_nerr)
5873 return ("Unknown error");
5874 return (sys_errlist[errnum]);
5879 malloc(size_t nbytes)
5882 return (__crt_malloc(nbytes));
5886 calloc(size_t num, size_t size)
5889 return (__crt_calloc(num, size));
5900 realloc(void *cp, size_t nbytes)
5903 return (__crt_realloc(cp, nbytes));
5906 extern int _rtld_version__FreeBSD_version __exported;
5907 int _rtld_version__FreeBSD_version = __FreeBSD_version;
5909 extern char _rtld_version_laddr_offset __exported;
5910 char _rtld_version_laddr_offset;