2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>.
7 * Copyright 2012 John Marino <draco@marino.st>.
8 * Copyright 2014-2017 The FreeBSD Foundation
11 * Portions of this software were developed by Konstantin Belousov
12 * under sponsorship from the FreeBSD Foundation.
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 * Dynamic linker for ELF.
38 * John Polstra <jdp@polstra.com>.
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
44 #include <sys/param.h>
45 #include <sys/mount.h>
48 #include <sys/sysctl.h>
50 #include <sys/utsname.h>
51 #include <sys/ktrace.h>
68 #include "rtld_printf.h"
69 #include "rtld_malloc.h"
70 #include "rtld_utrace.h"
74 typedef void (*func_ptr_type)(void);
75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
78 /* Variables that cannot be static: */
79 extern struct r_debug r_debug; /* For GDB */
80 extern int _thread_autoinit_dummy_decl;
81 extern char* __progname;
82 extern void (*__cleanup)(void);
86 * Function declarations.
88 static const char *basename(const char *);
89 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
90 const Elf_Dyn **, const Elf_Dyn **);
91 static 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 void __pthread_cxa_finalize(struct dl_phdr_info *a);
256 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp);
257 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff);
261 static int osreldate;
264 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
265 static int max_stack_flags;
268 * Global declarations normally provided by crt1. The dynamic linker is
269 * not built with crt1, so we have to provide them ourselves.
275 * Used to pass argc, argv to init functions.
281 * Globals to control TLS allocation.
283 size_t tls_last_offset; /* Static TLS offset of last module */
284 size_t tls_last_size; /* Static TLS size of last module */
285 size_t tls_static_space; /* Static TLS space allocated */
286 static size_t tls_static_max_align;
287 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */
288 int tls_max_index = 1; /* Largest module index allocated */
290 static bool ld_library_path_rpath = 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;
389 bool dir_enable, direct_exec, explicit_fd, search_in_path;
392 * On entry, the dynamic linker itself has not been relocated yet.
393 * Be very careful not to reference any global data until after
394 * init_rtld has returned. It is OK to reference file-scope statics
395 * and string constants, and to call static and global functions.
398 /* Find the auxiliary vector on the stack. */
402 sp += argc + 1; /* Skip over arguments and NULL terminator */
404 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
406 aux = (Elf_Auxinfo *) sp;
408 /* Digest the auxiliary vector. */
409 for (i = 0; i < AT_COUNT; i++)
411 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
412 if (auxp->a_type < AT_COUNT)
413 aux_info[auxp->a_type] = auxp;
416 /* Initialize and relocate ourselves. */
417 assert(aux_info[AT_BASE] != NULL);
418 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
420 __progname = obj_rtld.path;
421 argv0 = argv[0] != NULL ? argv[0] : "(null)";
426 trust = !issetugid();
429 md_abi_variant_hook(aux_info);
432 if (aux_info[AT_EXECFD] != NULL) {
433 fd = aux_info[AT_EXECFD]->a_un.a_val;
435 assert(aux_info[AT_PHDR] != NULL);
436 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
437 if (phdr == obj_rtld.phdr) {
439 _rtld_error("Tainted process refusing to run binary %s",
446 * Set osrel for us, it is later reset to the binary'
447 * value before first instruction of code from the binary
452 mib[2] = KERN_PROC_OSREL;
454 osrel = __FreeBSD_version;
455 sz = sizeof(old_osrel);
456 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel));
458 dbg("opening main program in direct exec mode");
460 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, &argv0);
461 explicit_fd = (fd != -1);
464 fd = open_binary_fd(argv0, search_in_path, &binpath);
465 if (fstat(fd, &st) == -1) {
466 _rtld_error("Failed to fstat FD %d (%s): %s", fd,
467 explicit_fd ? "user-provided descriptor" : argv0,
468 rtld_strerror(errno));
473 * Rough emulation of the permission checks done by
474 * execve(2), only Unix DACs are checked, ACLs are
475 * ignored. Preserve the semantic of disabling owner
476 * to execute if owner x bit is cleared, even if
477 * others x bit is enabled.
478 * mmap(2) does not allow to mmap with PROT_EXEC if
479 * binary' file comes from noexec mount. We cannot
480 * set a text reference on the binary.
483 if (st.st_uid == geteuid()) {
484 if ((st.st_mode & S_IXUSR) != 0)
486 } else if (st.st_gid == getegid()) {
487 if ((st.st_mode & S_IXGRP) != 0)
489 } else if ((st.st_mode & S_IXOTH) != 0) {
493 _rtld_error("No execute permission for binary %s",
499 * For direct exec mode, argv[0] is the interpreter
500 * name, we must remove it and shift arguments left
501 * before invoking binary main. Since stack layout
502 * places environment pointers and aux vectors right
503 * after the terminating NULL, we must shift
504 * environment and aux as well.
506 main_argc = argc - rtld_argc;
507 for (i = 0; i <= main_argc; i++)
508 argv[i] = argv[i + rtld_argc];
510 environ = env = envp = argv + main_argc + 1;
512 *envp = *(envp + rtld_argc);
514 } while (*envp != NULL);
515 aux = auxp = (Elf_Auxinfo *)envp;
516 auxpf = (Elf_Auxinfo *)(envp + rtld_argc);
517 /* XXXKIB insert place for AT_EXECPATH if not present */
518 for (;; auxp++, auxpf++) {
520 if (auxp->a_type == AT_NULL)
524 /* Point AT_EXECPATH auxv and aux_info to the binary path. */
525 if (binpath == NULL) {
526 aux_info[AT_EXECPATH] = NULL;
528 if (aux_info[AT_EXECPATH] == NULL) {
529 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo));
530 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH;
532 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *,
536 _rtld_error("No binary");
542 ld_bind_now = getenv(_LD("BIND_NOW"));
545 * If the process is tainted, then we un-set the dangerous environment
546 * variables. The process will be marked as tainted until setuid(2)
547 * is called. If any child process calls setuid(2) we do not want any
548 * future processes to honor the potentially un-safe variables.
551 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) ||
552 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) ||
553 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) ||
554 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) ||
555 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) {
556 _rtld_error("environment corrupt; aborting");
560 ld_debug = getenv(_LD("DEBUG"));
561 if (ld_bind_now == NULL)
562 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL;
563 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL;
564 libmap_override = getenv(_LD("LIBMAP"));
565 ld_library_path = getenv(_LD("LIBRARY_PATH"));
566 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS"));
567 ld_preload = getenv(_LD("PRELOAD"));
568 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH"));
569 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL;
570 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH"));
571 if (library_path_rpath != NULL) {
572 if (library_path_rpath[0] == 'y' ||
573 library_path_rpath[0] == 'Y' ||
574 library_path_rpath[0] == '1')
575 ld_library_path_rpath = true;
577 ld_library_path_rpath = false;
579 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
580 (ld_library_path != NULL) || (ld_preload != NULL) ||
581 (ld_elf_hints_path != NULL) || ld_loadfltr;
582 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS"));
583 ld_utrace = getenv(_LD("UTRACE"));
585 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
586 ld_elf_hints_path = ld_elf_hints_default;
588 if (ld_debug != NULL && *ld_debug != '\0')
590 dbg("%s is initialized, base address = %p", __progname,
591 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
592 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
593 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
595 dbg("initializing thread locks");
599 * Load the main program, or process its program header if it is
602 if (fd != -1) { /* Load the main program. */
603 dbg("loading main program");
604 obj_main = map_object(fd, argv0, NULL);
606 if (obj_main == NULL)
608 max_stack_flags = obj_main->stack_flags;
609 } else { /* Main program already loaded. */
610 dbg("processing main program's program header");
611 assert(aux_info[AT_PHDR] != NULL);
612 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
613 assert(aux_info[AT_PHNUM] != NULL);
614 phnum = aux_info[AT_PHNUM]->a_un.a_val;
615 assert(aux_info[AT_PHENT] != NULL);
616 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
617 assert(aux_info[AT_ENTRY] != NULL);
618 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
619 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL)
623 if (aux_info[AT_EXECPATH] != NULL && fd == -1) {
624 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
625 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
626 if (kexecpath[0] == '/')
627 obj_main->path = kexecpath;
628 else if (getcwd(buf, sizeof(buf)) == NULL ||
629 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
630 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
631 obj_main->path = xstrdup(argv0);
633 obj_main->path = xstrdup(buf);
635 dbg("No AT_EXECPATH or direct exec");
636 obj_main->path = xstrdup(argv0);
638 dbg("obj_main path %s", obj_main->path);
639 obj_main->mainprog = true;
641 if (aux_info[AT_STACKPROT] != NULL &&
642 aux_info[AT_STACKPROT]->a_un.a_val != 0)
643 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
647 * Get the actual dynamic linker pathname from the executable if
648 * possible. (It should always be possible.) That ensures that
649 * gdb will find the right dynamic linker even if a non-standard
652 if (obj_main->interp != NULL &&
653 strcmp(obj_main->interp, obj_rtld.path) != 0) {
655 obj_rtld.path = xstrdup(obj_main->interp);
656 __progname = obj_rtld.path;
660 if (!digest_dynamic(obj_main, 0))
662 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
663 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
664 obj_main->dynsymcount);
666 linkmap_add(obj_main);
667 linkmap_add(&obj_rtld);
669 /* Link the main program into the list of objects. */
670 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
674 /* Initialize a fake symbol for resolving undefined weak references. */
675 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
676 sym_zero.st_shndx = SHN_UNDEF;
677 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
680 libmap_disable = (bool)lm_init(libmap_override);
682 dbg("loading LD_PRELOAD libraries");
683 if (load_preload_objects() == -1)
685 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
687 dbg("loading needed objects");
688 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE :
692 /* Make a list of all objects loaded at startup. */
693 last_interposer = obj_main;
694 TAILQ_FOREACH(obj, &obj_list, next) {
697 if (obj->z_interpose && obj != obj_main) {
698 objlist_put_after(&list_main, last_interposer, obj);
699 last_interposer = obj;
701 objlist_push_tail(&list_main, obj);
706 dbg("checking for required versions");
707 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
710 if (ld_tracing) { /* We're done */
711 trace_loaded_objects(obj_main);
715 if (getenv(_LD("DUMP_REL_PRE")) != NULL) {
716 dump_relocations(obj_main);
721 * Processing tls relocations requires having the tls offsets
722 * initialized. Prepare offsets before starting initial
723 * relocation processing.
725 dbg("initializing initial thread local storage offsets");
726 STAILQ_FOREACH(entry, &list_main, link) {
728 * Allocate all the initial objects out of the static TLS
729 * block even if they didn't ask for it.
731 allocate_tls_offset(entry->obj);
734 if (relocate_objects(obj_main,
735 ld_bind_now != NULL && *ld_bind_now != '\0',
736 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
739 dbg("doing copy relocations");
740 if (do_copy_relocations(obj_main) == -1)
743 if (getenv(_LD("DUMP_REL_POST")) != NULL) {
744 dump_relocations(obj_main);
751 * Setup TLS for main thread. This must be done after the
752 * relocations are processed, since tls initialization section
753 * might be the subject for relocations.
755 dbg("initializing initial thread local storage");
756 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
758 dbg("initializing key program variables");
759 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
760 set_program_var("environ", env);
761 set_program_var("__elf_aux_vector", aux);
763 /* Make a list of init functions to call. */
764 objlist_init(&initlist);
765 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)),
766 preload_tail, &initlist);
768 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
770 map_stacks_exec(NULL);
772 if (!obj_main->crt_no_init) {
774 * Make sure we don't call the main program's init and fini
775 * functions for binaries linked with old crt1 which calls
778 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
779 obj_main->preinit_array = obj_main->init_array =
780 obj_main->fini_array = (Elf_Addr)NULL;
784 * Execute MD initializers required before we call the objects'
790 /* Set osrel for direct-execed binary */
793 mib[2] = KERN_PROC_OSREL;
795 osrel = obj_main->osrel;
796 sz = sizeof(old_osrel);
797 dbg("setting osrel to %d", osrel);
798 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel));
801 wlock_acquire(rtld_bind_lock, &lockstate);
803 dbg("resolving ifuncs");
804 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL &&
805 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1)
808 rtld_exit_ptr = rtld_exit;
809 if (obj_main->crt_no_init)
811 objlist_call_init(&initlist, &lockstate);
812 _r_debug_postinit(&obj_main->linkmap);
813 objlist_clear(&initlist);
814 dbg("loading filtees");
815 TAILQ_FOREACH(obj, &obj_list, next) {
818 if (ld_loadfltr || obj->z_loadfltr)
819 load_filtees(obj, 0, &lockstate);
822 dbg("enforcing main obj relro");
823 if (obj_enforce_relro(obj_main) == -1)
826 lock_release(rtld_bind_lock, &lockstate);
828 dbg("transferring control to program entry point = %p", obj_main->entry);
830 /* Return the exit procedure and the program entry point. */
831 *exit_proc = rtld_exit_ptr;
833 return (func_ptr_type) obj_main->entry;
837 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
842 ptr = (void *)make_function_pointer(def, obj);
843 target = call_ifunc_resolver(ptr);
844 return ((void *)target);
848 * NB: MIPS uses a private version of this function (_mips_rtld_bind).
849 * Changes to this function should be applied there as well.
852 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
856 const Obj_Entry *defobj;
859 RtldLockState lockstate;
861 rlock_acquire(rtld_bind_lock, &lockstate);
862 if (sigsetjmp(lockstate.env, 0) != 0)
863 lock_upgrade(rtld_bind_lock, &lockstate);
865 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff);
867 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff);
869 where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
870 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
874 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
875 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
877 target = (Elf_Addr)(defobj->relocbase + def->st_value);
879 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
880 defobj->strtab + def->st_name, basename(obj->path),
881 (void *)target, basename(defobj->path));
884 * Write the new contents for the jmpslot. Note that depending on
885 * architecture, the value which we need to return back to the
886 * lazy binding trampoline may or may not be the target
887 * address. The value returned from reloc_jmpslot() is the value
888 * that the trampoline needs.
890 target = reloc_jmpslot(where, target, defobj, obj, rel);
891 lock_release(rtld_bind_lock, &lockstate);
896 * Error reporting function. Use it like printf. If formats the message
897 * into a buffer, and sets things up so that the next call to dlerror()
898 * will return the message.
901 _rtld_error(const char *fmt, ...)
903 static char buf[512];
907 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
910 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message);
914 * Return a dynamically-allocated copy of the current error message, if any.
919 return error_message == NULL ? NULL : xstrdup(error_message);
923 * Restore the current error message from a copy which was previously saved
924 * by errmsg_save(). The copy is freed.
927 errmsg_restore(char *saved_msg)
929 if (saved_msg == NULL)
930 error_message = NULL;
932 _rtld_error("%s", saved_msg);
938 basename(const char *name)
940 const char *p = strrchr(name, '/');
941 return p != NULL ? p + 1 : name;
944 static struct utsname uts;
947 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
948 const char *subst, bool may_free)
950 char *p, *p1, *res, *resp;
951 int subst_len, kw_len, subst_count, old_len, new_len;
956 * First, count the number of the keyword occurrences, to
957 * preallocate the final string.
959 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
966 * If the keyword is not found, just return.
968 * Return non-substituted string if resolution failed. We
969 * cannot do anything more reasonable, the failure mode of the
970 * caller is unresolved library anyway.
972 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
973 return (may_free ? real : xstrdup(real));
975 subst = obj->origin_path;
978 * There is indeed something to substitute. Calculate the
979 * length of the resulting string, and allocate it.
981 subst_len = strlen(subst);
982 old_len = strlen(real);
983 new_len = old_len + (subst_len - kw_len) * subst_count;
984 res = xmalloc(new_len + 1);
987 * Now, execute the substitution loop.
989 for (p = real, resp = res, *resp = '\0';;) {
992 /* Copy the prefix before keyword. */
993 memcpy(resp, p, p1 - p);
995 /* Keyword replacement. */
996 memcpy(resp, subst, subst_len);
1004 /* Copy to the end of string and finish. */
1012 origin_subst(Obj_Entry *obj, const char *real)
1014 char *res1, *res2, *res3, *res4;
1016 if (obj == NULL || !trust)
1017 return (xstrdup(real));
1018 if (uts.sysname[0] == '\0') {
1019 if (uname(&uts) != 0) {
1020 _rtld_error("utsname failed: %d", errno);
1024 /* __DECONST is safe here since without may_free real is unchanged */
1025 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL,
1027 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
1028 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
1029 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
1036 const char *msg = dlerror();
1039 msg = "Fatal error";
1040 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": ");
1041 rtld_fdputstr(STDERR_FILENO, msg);
1042 rtld_fdputchar(STDERR_FILENO, '\n');
1047 * Process a shared object's DYNAMIC section, and save the important
1048 * information in its Obj_Entry structure.
1051 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
1052 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
1054 const Elf_Dyn *dynp;
1055 Needed_Entry **needed_tail = &obj->needed;
1056 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
1057 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
1058 const Elf_Hashelt *hashtab;
1059 const Elf32_Word *hashval;
1060 Elf32_Word bkt, nmaskwords;
1062 int plttype = DT_REL;
1066 *dyn_runpath = NULL;
1068 obj->bind_now = false;
1069 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
1070 switch (dynp->d_tag) {
1073 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr);
1077 obj->relsize = dynp->d_un.d_val;
1081 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1085 obj->pltrel = (const Elf_Rel *)
1086 (obj->relocbase + dynp->d_un.d_ptr);
1090 obj->pltrelsize = dynp->d_un.d_val;
1094 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr);
1098 obj->relasize = dynp->d_un.d_val;
1102 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1106 plttype = dynp->d_un.d_val;
1107 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1111 obj->symtab = (const Elf_Sym *)
1112 (obj->relocbase + dynp->d_un.d_ptr);
1116 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1120 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr);
1124 obj->strsize = dynp->d_un.d_val;
1128 obj->verneed = (const Elf_Verneed *)(obj->relocbase +
1133 obj->verneednum = dynp->d_un.d_val;
1137 obj->verdef = (const Elf_Verdef *)(obj->relocbase +
1142 obj->verdefnum = dynp->d_un.d_val;
1146 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1152 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1154 obj->nbuckets = hashtab[0];
1155 obj->nchains = hashtab[1];
1156 obj->buckets = hashtab + 2;
1157 obj->chains = obj->buckets + obj->nbuckets;
1158 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1159 obj->buckets != NULL;
1165 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1167 obj->nbuckets_gnu = hashtab[0];
1168 obj->symndx_gnu = hashtab[1];
1169 nmaskwords = hashtab[2];
1170 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1171 obj->maskwords_bm_gnu = nmaskwords - 1;
1172 obj->shift2_gnu = hashtab[3];
1173 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4);
1174 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1175 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1177 /* Number of bitmask words is required to be power of 2 */
1178 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1179 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1185 Needed_Entry *nep = NEW(Needed_Entry);
1186 nep->name = dynp->d_un.d_val;
1191 needed_tail = &nep->next;
1197 Needed_Entry *nep = NEW(Needed_Entry);
1198 nep->name = dynp->d_un.d_val;
1202 *needed_filtees_tail = nep;
1203 needed_filtees_tail = &nep->next;
1205 if (obj->linkmap.l_refname == NULL)
1206 obj->linkmap.l_refname = (char *)dynp->d_un.d_val;
1212 Needed_Entry *nep = NEW(Needed_Entry);
1213 nep->name = dynp->d_un.d_val;
1217 *needed_aux_filtees_tail = nep;
1218 needed_aux_filtees_tail = &nep->next;
1223 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr);
1227 obj->textrel = true;
1231 obj->symbolic = true;
1236 * We have to wait until later to process this, because we
1237 * might not have gotten the address of the string table yet.
1247 *dyn_runpath = dynp;
1251 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1254 case DT_PREINIT_ARRAY:
1255 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1258 case DT_PREINIT_ARRAYSZ:
1259 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1263 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1266 case DT_INIT_ARRAYSZ:
1267 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1271 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1275 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1278 case DT_FINI_ARRAYSZ:
1279 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1283 * Don't process DT_DEBUG on MIPS as the dynamic section
1284 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1290 dbg("Filling in DT_DEBUG entry");
1291 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug;
1296 if (dynp->d_un.d_val & DF_ORIGIN)
1297 obj->z_origin = true;
1298 if (dynp->d_un.d_val & DF_SYMBOLIC)
1299 obj->symbolic = true;
1300 if (dynp->d_un.d_val & DF_TEXTREL)
1301 obj->textrel = true;
1302 if (dynp->d_un.d_val & DF_BIND_NOW)
1303 obj->bind_now = true;
1304 if (dynp->d_un.d_val & DF_STATIC_TLS)
1305 obj->static_tls = true;
1308 case DT_MIPS_LOCAL_GOTNO:
1309 obj->local_gotno = dynp->d_un.d_val;
1312 case DT_MIPS_SYMTABNO:
1313 obj->symtabno = dynp->d_un.d_val;
1316 case DT_MIPS_GOTSYM:
1317 obj->gotsym = dynp->d_un.d_val;
1320 case DT_MIPS_RLD_MAP:
1321 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1324 case DT_MIPS_PLTGOT:
1325 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase +
1331 #ifdef __powerpc64__
1332 case DT_PPC64_GLINK:
1333 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1338 if (dynp->d_un.d_val & DF_1_NOOPEN)
1339 obj->z_noopen = true;
1340 if (dynp->d_un.d_val & DF_1_ORIGIN)
1341 obj->z_origin = true;
1342 if (dynp->d_un.d_val & DF_1_GLOBAL)
1343 obj->z_global = true;
1344 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1345 obj->bind_now = true;
1346 if (dynp->d_un.d_val & DF_1_NODELETE)
1347 obj->z_nodelete = true;
1348 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1349 obj->z_loadfltr = true;
1350 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1351 obj->z_interpose = true;
1352 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1353 obj->z_nodeflib = true;
1354 if (dynp->d_un.d_val & DF_1_PIE)
1360 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1367 obj->traced = false;
1369 if (plttype == DT_RELA) {
1370 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1372 obj->pltrelasize = obj->pltrelsize;
1373 obj->pltrelsize = 0;
1376 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1377 if (obj->valid_hash_sysv)
1378 obj->dynsymcount = obj->nchains;
1379 else if (obj->valid_hash_gnu) {
1380 obj->dynsymcount = 0;
1381 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1382 if (obj->buckets_gnu[bkt] == 0)
1384 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1387 while ((*hashval++ & 1u) == 0);
1389 obj->dynsymcount += obj->symndx_gnu;
1392 if (obj->linkmap.l_refname != NULL)
1393 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj->
1398 obj_resolve_origin(Obj_Entry *obj)
1401 if (obj->origin_path != NULL)
1403 obj->origin_path = xmalloc(PATH_MAX);
1404 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1408 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1409 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1412 if (obj->z_origin && !obj_resolve_origin(obj))
1415 if (dyn_runpath != NULL) {
1416 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val;
1417 obj->runpath = origin_subst(obj, obj->runpath);
1418 } else if (dyn_rpath != NULL) {
1419 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val;
1420 obj->rpath = origin_subst(obj, obj->rpath);
1422 if (dyn_soname != NULL)
1423 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1428 digest_dynamic(Obj_Entry *obj, int early)
1430 const Elf_Dyn *dyn_rpath;
1431 const Elf_Dyn *dyn_soname;
1432 const Elf_Dyn *dyn_runpath;
1434 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1435 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath));
1439 * Process a shared object's program header. This is used only for the
1440 * main program, when the kernel has already loaded the main program
1441 * into memory before calling the dynamic linker. It creates and
1442 * returns an Obj_Entry structure.
1445 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1448 const Elf_Phdr *phlimit = phdr + phnum;
1450 Elf_Addr note_start, note_end;
1454 for (ph = phdr; ph < phlimit; ph++) {
1455 if (ph->p_type != PT_PHDR)
1459 obj->phsize = ph->p_memsz;
1460 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr;
1464 obj->stack_flags = PF_X | PF_R | PF_W;
1466 for (ph = phdr; ph < phlimit; ph++) {
1467 switch (ph->p_type) {
1470 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1474 if (nsegs == 0) { /* First load segment */
1475 obj->vaddrbase = trunc_page(ph->p_vaddr);
1476 obj->mapbase = obj->vaddrbase + obj->relocbase;
1477 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1479 } else { /* Last load segment */
1480 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1487 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1492 obj->tlssize = ph->p_memsz;
1493 obj->tlsalign = ph->p_align;
1494 obj->tlsinitsize = ph->p_filesz;
1495 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1496 obj->tlspoffset = ph->p_offset;
1500 obj->stack_flags = ph->p_flags;
1504 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1505 obj->relro_size = round_page(ph->p_memsz);
1509 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1510 note_end = note_start + ph->p_filesz;
1511 digest_notes(obj, note_start, note_end);
1516 _rtld_error("%s: too few PT_LOAD segments", path);
1525 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1527 const Elf_Note *note;
1528 const char *note_name;
1531 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1532 note = (const Elf_Note *)((const char *)(note + 1) +
1533 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1534 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1535 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1536 note->n_descsz != sizeof(int32_t))
1538 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1539 note->n_type != NT_FREEBSD_FEATURE_CTL &&
1540 note->n_type != NT_FREEBSD_NOINIT_TAG)
1542 note_name = (const char *)(note + 1);
1543 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1544 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1546 switch (note->n_type) {
1547 case NT_FREEBSD_ABI_TAG:
1548 /* FreeBSD osrel note */
1549 p = (uintptr_t)(note + 1);
1550 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1551 obj->osrel = *(const int32_t *)(p);
1552 dbg("note osrel %d", obj->osrel);
1554 case NT_FREEBSD_FEATURE_CTL:
1555 /* FreeBSD ABI feature control note */
1556 p = (uintptr_t)(note + 1);
1557 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1558 obj->fctl0 = *(const uint32_t *)(p);
1559 dbg("note fctl0 %#x", obj->fctl0);
1561 case NT_FREEBSD_NOINIT_TAG:
1562 /* FreeBSD 'crt does not call init' note */
1563 obj->crt_no_init = true;
1564 dbg("note crt_no_init");
1571 dlcheck(void *handle)
1575 TAILQ_FOREACH(obj, &obj_list, next) {
1576 if (obj == (Obj_Entry *) handle)
1580 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1581 _rtld_error("Invalid shared object handle %p", handle);
1588 * If the given object is already in the donelist, return true. Otherwise
1589 * add the object to the list and return false.
1592 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1596 for (i = 0; i < dlp->num_used; i++)
1597 if (dlp->objs[i] == obj)
1600 * Our donelist allocation should always be sufficient. But if
1601 * our threads locking isn't working properly, more shared objects
1602 * could have been loaded since we allocated the list. That should
1603 * never happen, but we'll handle it properly just in case it does.
1605 if (dlp->num_used < dlp->num_alloc)
1606 dlp->objs[dlp->num_used++] = obj;
1611 * Hash function for symbol table lookup. Don't even think about changing
1612 * this. It is specified by the System V ABI.
1615 elf_hash(const char *name)
1617 const unsigned char *p = (const unsigned char *) name;
1618 unsigned long h = 0;
1621 while (*p != '\0') {
1622 h = (h << 4) + *p++;
1623 if ((g = h & 0xf0000000) != 0)
1631 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1632 * unsigned in case it's implemented with a wider type.
1635 gnu_hash(const char *s)
1641 for (c = *s; c != '\0'; c = *++s)
1643 return (h & 0xffffffff);
1648 * Find the library with the given name, and return its full pathname.
1649 * The returned string is dynamically allocated. Generates an error
1650 * message and returns NULL if the library cannot be found.
1652 * If the second argument is non-NULL, then it refers to an already-
1653 * loaded shared object, whose library search path will be searched.
1655 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1656 * descriptor (which is close-on-exec) will be passed out via the third
1659 * The search order is:
1660 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1661 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1663 * DT_RUNPATH in the referencing file
1664 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1666 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1668 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1671 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1673 char *pathname, *refobj_path;
1675 bool nodeflib, objgiven;
1677 objgiven = refobj != NULL;
1679 if (libmap_disable || !objgiven ||
1680 (name = lm_find(refobj->path, xname)) == NULL)
1683 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1684 if (name[0] != '/' && !trust) {
1685 _rtld_error("Absolute pathname required "
1686 "for shared object \"%s\"", name);
1689 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1690 __DECONST(char *, name)));
1693 dbg(" Searching for \"%s\"", name);
1694 refobj_path = objgiven ? refobj->path : NULL;
1697 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1698 * back to pre-conforming behaviour if user requested so with
1699 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1702 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1703 pathname = search_library_path(name, ld_library_path,
1705 if (pathname != NULL)
1707 if (refobj != NULL) {
1708 pathname = search_library_path(name, refobj->rpath,
1710 if (pathname != NULL)
1713 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1714 if (pathname != NULL)
1716 pathname = search_library_path(name, gethints(false),
1718 if (pathname != NULL)
1720 pathname = search_library_path(name, ld_standard_library_path,
1722 if (pathname != NULL)
1725 nodeflib = objgiven ? refobj->z_nodeflib : false;
1727 pathname = search_library_path(name, refobj->rpath,
1729 if (pathname != NULL)
1732 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1733 pathname = search_library_path(name, obj_main->rpath,
1735 if (pathname != NULL)
1738 pathname = search_library_path(name, ld_library_path,
1740 if (pathname != NULL)
1743 pathname = search_library_path(name, refobj->runpath,
1745 if (pathname != NULL)
1748 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1749 if (pathname != NULL)
1751 pathname = search_library_path(name, gethints(nodeflib),
1753 if (pathname != NULL)
1755 if (objgiven && !nodeflib) {
1756 pathname = search_library_path(name,
1757 ld_standard_library_path, refobj_path, fdp);
1758 if (pathname != NULL)
1763 if (objgiven && refobj->path != NULL) {
1764 _rtld_error("Shared object \"%s\" not found, "
1765 "required by \"%s\"", name, basename(refobj->path));
1767 _rtld_error("Shared object \"%s\" not found", name);
1773 * Given a symbol number in a referencing object, find the corresponding
1774 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1775 * no definition was found. Returns a pointer to the Obj_Entry of the
1776 * defining object via the reference parameter DEFOBJ_OUT.
1779 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1780 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1781 RtldLockState *lockstate)
1785 const Obj_Entry *defobj;
1786 const Ver_Entry *ve;
1792 * If we have already found this symbol, get the information from
1795 if (symnum >= refobj->dynsymcount)
1796 return NULL; /* Bad object */
1797 if (cache != NULL && cache[symnum].sym != NULL) {
1798 *defobj_out = cache[symnum].obj;
1799 return cache[symnum].sym;
1802 ref = refobj->symtab + symnum;
1803 name = refobj->strtab + ref->st_name;
1809 * We don't have to do a full scale lookup if the symbol is local.
1810 * We know it will bind to the instance in this load module; to
1811 * which we already have a pointer (ie ref). By not doing a lookup,
1812 * we not only improve performance, but it also avoids unresolvable
1813 * symbols when local symbols are not in the hash table. This has
1814 * been seen with the ia64 toolchain.
1816 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1817 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1818 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1821 symlook_init(&req, name);
1823 ve = req.ventry = fetch_ventry(refobj, symnum);
1824 req.lockstate = lockstate;
1825 res = symlook_default(&req, refobj);
1828 defobj = req.defobj_out;
1836 * If we found no definition and the reference is weak, treat the
1837 * symbol as having the value zero.
1839 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1845 *defobj_out = defobj;
1846 /* Record the information in the cache to avoid subsequent lookups. */
1847 if (cache != NULL) {
1848 cache[symnum].sym = def;
1849 cache[symnum].obj = defobj;
1852 if (refobj != &obj_rtld)
1853 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name,
1854 ve != NULL ? "@" : "", ve != NULL ? ve->name : "");
1860 * Return the search path from the ldconfig hints file, reading it if
1861 * necessary. If nostdlib is true, then the default search paths are
1862 * not added to result.
1864 * Returns NULL if there are problems with the hints file,
1865 * or if the search path there is empty.
1868 gethints(bool nostdlib)
1870 static char *filtered_path;
1871 static const char *hints;
1872 static struct elfhints_hdr hdr;
1873 struct fill_search_info_args sargs, hargs;
1874 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1875 struct dl_serpath *SLPpath, *hintpath;
1877 struct stat hint_stat;
1878 unsigned int SLPndx, hintndx, fndx, fcount;
1884 /* First call, read the hints file */
1885 if (hints == NULL) {
1886 /* Keep from trying again in case the hints file is bad. */
1889 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1893 * Check of hdr.dirlistlen value against type limit
1894 * intends to pacify static analyzers. Further
1895 * paranoia leads to checks that dirlist is fully
1896 * contained in the file range.
1898 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1899 hdr.magic != ELFHINTS_MAGIC ||
1900 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 ||
1901 fstat(fd, &hint_stat) == -1) {
1908 if (dl + hdr.dirlist < dl)
1911 if (dl + hdr.dirlistlen < dl)
1913 dl += hdr.dirlistlen;
1914 if (dl > hint_stat.st_size)
1916 p = xmalloc(hdr.dirlistlen + 1);
1917 if (pread(fd, p, hdr.dirlistlen + 1,
1918 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 ||
1919 p[hdr.dirlistlen] != '\0') {
1928 * If caller agreed to receive list which includes the default
1929 * paths, we are done. Otherwise, if we still did not
1930 * calculated filtered result, do it now.
1933 return (hints[0] != '\0' ? hints : NULL);
1934 if (filtered_path != NULL)
1938 * Obtain the list of all configured search paths, and the
1939 * list of the default paths.
1941 * First estimate the size of the results.
1943 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1945 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1948 sargs.request = RTLD_DI_SERINFOSIZE;
1949 sargs.serinfo = &smeta;
1950 hargs.request = RTLD_DI_SERINFOSIZE;
1951 hargs.serinfo = &hmeta;
1953 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1955 path_enumerate(hints, fill_search_info, NULL, &hargs);
1957 SLPinfo = xmalloc(smeta.dls_size);
1958 hintinfo = xmalloc(hmeta.dls_size);
1961 * Next fetch both sets of paths.
1963 sargs.request = RTLD_DI_SERINFO;
1964 sargs.serinfo = SLPinfo;
1965 sargs.serpath = &SLPinfo->dls_serpath[0];
1966 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1968 hargs.request = RTLD_DI_SERINFO;
1969 hargs.serinfo = hintinfo;
1970 hargs.serpath = &hintinfo->dls_serpath[0];
1971 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1973 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1975 path_enumerate(hints, fill_search_info, NULL, &hargs);
1978 * Now calculate the difference between two sets, by excluding
1979 * standard paths from the full set.
1983 filtered_path = xmalloc(hdr.dirlistlen + 1);
1984 hintpath = &hintinfo->dls_serpath[0];
1985 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1987 SLPpath = &SLPinfo->dls_serpath[0];
1989 * Check each standard path against current.
1991 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1992 /* matched, skip the path */
1993 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
2001 * Not matched against any standard path, add the path
2002 * to result. Separate consequtive paths with ':'.
2005 filtered_path[fndx] = ':';
2009 flen = strlen(hintpath->dls_name);
2010 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
2013 filtered_path[fndx] = '\0';
2019 return (filtered_path[0] != '\0' ? filtered_path : NULL);
2023 init_dag(Obj_Entry *root)
2025 const Needed_Entry *needed;
2026 const Objlist_Entry *elm;
2029 if (root->dag_inited)
2031 donelist_init(&donelist);
2033 /* Root object belongs to own DAG. */
2034 objlist_push_tail(&root->dldags, root);
2035 objlist_push_tail(&root->dagmembers, root);
2036 donelist_check(&donelist, root);
2039 * Add dependencies of root object to DAG in breadth order
2040 * by exploiting the fact that each new object get added
2041 * to the tail of the dagmembers list.
2043 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2044 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
2045 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
2047 objlist_push_tail(&needed->obj->dldags, root);
2048 objlist_push_tail(&root->dagmembers, needed->obj);
2051 root->dag_inited = true;
2055 init_marker(Obj_Entry *marker)
2058 bzero(marker, sizeof(*marker));
2059 marker->marker = true;
2063 globallist_curr(const Obj_Entry *obj)
2070 return (__DECONST(Obj_Entry *, obj));
2071 obj = TAILQ_PREV(obj, obj_entry_q, next);
2076 globallist_next(const Obj_Entry *obj)
2080 obj = TAILQ_NEXT(obj, next);
2084 return (__DECONST(Obj_Entry *, obj));
2088 /* Prevent the object from being unmapped while the bind lock is dropped. */
2090 hold_object(Obj_Entry *obj)
2097 unhold_object(Obj_Entry *obj)
2100 assert(obj->holdcount > 0);
2101 if (--obj->holdcount == 0 && obj->unholdfree)
2102 release_object(obj);
2106 process_z(Obj_Entry *root)
2108 const Objlist_Entry *elm;
2112 * Walk over object DAG and process every dependent object
2113 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2114 * to grow their own DAG.
2116 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2117 * symlook_global() to work.
2119 * For DF_1_NODELETE, the DAG should have its reference upped.
2121 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2125 if (obj->z_nodelete && !obj->ref_nodel) {
2126 dbg("obj %s -z nodelete", obj->path);
2129 obj->ref_nodel = true;
2131 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2132 dbg("obj %s -z global", obj->path);
2133 objlist_push_tail(&list_global, obj);
2139 * Initialize the dynamic linker. The argument is the address at which
2140 * the dynamic linker has been mapped into memory. The primary task of
2141 * this function is to relocate the dynamic linker.
2144 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2146 Obj_Entry objtmp; /* Temporary rtld object */
2147 const Elf_Ehdr *ehdr;
2148 const Elf_Dyn *dyn_rpath;
2149 const Elf_Dyn *dyn_soname;
2150 const Elf_Dyn *dyn_runpath;
2152 #ifdef RTLD_INIT_PAGESIZES_EARLY
2153 /* The page size is required by the dynamic memory allocator. */
2154 init_pagesizes(aux_info);
2158 * Conjure up an Obj_Entry structure for the dynamic linker.
2160 * The "path" member can't be initialized yet because string constants
2161 * cannot yet be accessed. Below we will set it correctly.
2163 memset(&objtmp, 0, sizeof(objtmp));
2166 objtmp.mapbase = mapbase;
2168 objtmp.relocbase = mapbase;
2171 objtmp.dynamic = rtld_dynamic(&objtmp);
2172 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2173 assert(objtmp.needed == NULL);
2174 #if !defined(__mips__)
2175 /* MIPS has a bogus DT_TEXTREL. */
2176 assert(!objtmp.textrel);
2179 * Temporarily put the dynamic linker entry into the object list, so
2180 * that symbols can be found.
2182 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2184 ehdr = (Elf_Ehdr *)mapbase;
2185 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2186 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]);
2188 /* Initialize the object list. */
2189 TAILQ_INIT(&obj_list);
2191 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2192 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2194 #ifndef RTLD_INIT_PAGESIZES_EARLY
2195 /* The page size is required by the dynamic memory allocator. */
2196 init_pagesizes(aux_info);
2199 if (aux_info[AT_OSRELDATE] != NULL)
2200 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2202 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2204 /* Replace the path with a dynamically allocated copy. */
2205 obj_rtld.path = xstrdup(ld_path_rtld);
2207 r_debug.r_brk = r_debug_state;
2208 r_debug.r_state = RT_CONSISTENT;
2212 * Retrieve the array of supported page sizes. The kernel provides the page
2213 * sizes in increasing order.
2216 init_pagesizes(Elf_Auxinfo **aux_info)
2218 static size_t psa[MAXPAGESIZES];
2222 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
2224 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2225 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2228 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2231 /* As a fallback, retrieve the base page size. */
2232 size = sizeof(psa[0]);
2233 if (aux_info[AT_PAGESZ] != NULL) {
2234 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2238 mib[1] = HW_PAGESIZE;
2242 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2243 _rtld_error("sysctl for hw.pagesize(s) failed");
2249 npagesizes = size / sizeof(pagesizes[0]);
2250 /* Discard any invalid entries at the end of the array. */
2251 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2256 * Add the init functions from a needed object list (and its recursive
2257 * needed objects) to "list". This is not used directly; it is a helper
2258 * function for initlist_add_objects(). The write lock must be held
2259 * when this function is called.
2262 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
2264 /* Recursively process the successor needed objects. */
2265 if (needed->next != NULL)
2266 initlist_add_neededs(needed->next, list);
2268 /* Process the current needed object. */
2269 if (needed->obj != NULL)
2270 initlist_add_objects(needed->obj, needed->obj, list);
2274 * Scan all of the DAGs rooted in the range of objects from "obj" to
2275 * "tail" and add their init functions to "list". This recurses over
2276 * the DAGs and ensure the proper init ordering such that each object's
2277 * needed libraries are initialized before the object itself. At the
2278 * same time, this function adds the objects to the global finalization
2279 * list "list_fini" in the opposite order. The write lock must be
2280 * held when this function is called.
2283 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2287 if (obj->init_scanned || obj->init_done)
2289 obj->init_scanned = true;
2291 /* Recursively process the successor objects. */
2292 nobj = globallist_next(obj);
2293 if (nobj != NULL && obj != tail)
2294 initlist_add_objects(nobj, tail, list);
2296 /* Recursively process the needed objects. */
2297 if (obj->needed != NULL)
2298 initlist_add_neededs(obj->needed, list);
2299 if (obj->needed_filtees != NULL)
2300 initlist_add_neededs(obj->needed_filtees, list);
2301 if (obj->needed_aux_filtees != NULL)
2302 initlist_add_neededs(obj->needed_aux_filtees, list);
2304 /* Add the object to the init list. */
2305 objlist_push_tail(list, obj);
2307 /* Add the object to the global fini list in the reverse order. */
2308 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2309 && !obj->on_fini_list) {
2310 objlist_push_head(&list_fini, obj);
2311 obj->on_fini_list = true;
2316 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2320 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2322 Needed_Entry *needed, *needed1;
2324 for (needed = n; needed != NULL; needed = needed->next) {
2325 if (needed->obj != NULL) {
2326 dlclose_locked(needed->obj, lockstate);
2330 for (needed = n; needed != NULL; needed = needed1) {
2331 needed1 = needed->next;
2337 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2340 free_needed_filtees(obj->needed_filtees, lockstate);
2341 obj->needed_filtees = NULL;
2342 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2343 obj->needed_aux_filtees = NULL;
2344 obj->filtees_loaded = false;
2348 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2349 RtldLockState *lockstate)
2352 for (; needed != NULL; needed = needed->next) {
2353 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2354 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2355 RTLD_LOCAL, lockstate);
2360 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2363 lock_restart_for_upgrade(lockstate);
2364 if (!obj->filtees_loaded) {
2365 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2366 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2367 obj->filtees_loaded = true;
2372 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2376 for (; needed != NULL; needed = needed->next) {
2377 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2378 flags & ~RTLD_LO_NOLOAD);
2379 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2386 * Given a shared object, traverse its list of needed objects, and load
2387 * each of them. Returns 0 on success. Generates an error message and
2388 * returns -1 on failure.
2391 load_needed_objects(Obj_Entry *first, int flags)
2395 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2398 if (process_needed(obj, obj->needed, flags) == -1)
2405 load_preload_objects(void)
2407 char *p = ld_preload;
2409 static const char delim[] = " \t:;";
2414 p += strspn(p, delim);
2415 while (*p != '\0') {
2416 size_t len = strcspn(p, delim);
2421 obj = load_object(p, -1, NULL, 0);
2423 return -1; /* XXX - cleanup */
2424 obj->z_interpose = true;
2427 p += strspn(p, delim);
2429 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2434 printable_path(const char *path)
2437 return (path == NULL ? "<unknown>" : path);
2441 * Load a shared object into memory, if it is not already loaded. The
2442 * object may be specified by name or by user-supplied file descriptor
2443 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2446 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2450 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2459 TAILQ_FOREACH(obj, &obj_list, next) {
2460 if (obj->marker || obj->doomed)
2462 if (object_match_name(obj, name))
2466 path = find_library(name, refobj, &fd);
2474 * search_library_pathfds() opens a fresh file descriptor for the
2475 * library, so there is no need to dup().
2477 } else if (fd_u == -1) {
2479 * If we didn't find a match by pathname, or the name is not
2480 * supplied, open the file and check again by device and inode.
2481 * This avoids false mismatches caused by multiple links or ".."
2484 * To avoid a race, we open the file and use fstat() rather than
2487 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2488 _rtld_error("Cannot open \"%s\"", path);
2493 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2495 _rtld_error("Cannot dup fd");
2500 if (fstat(fd, &sb) == -1) {
2501 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2506 TAILQ_FOREACH(obj, &obj_list, next) {
2507 if (obj->marker || obj->doomed)
2509 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2512 if (obj != NULL && name != NULL) {
2513 object_add_name(obj, name);
2518 if (flags & RTLD_LO_NOLOAD) {
2524 /* First use of this object, so we must map it in */
2525 obj = do_load_object(fd, name, path, &sb, flags);
2534 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2541 * but first, make sure that environment variables haven't been
2542 * used to circumvent the noexec flag on a filesystem.
2544 if (dangerous_ld_env) {
2545 if (fstatfs(fd, &fs) != 0) {
2546 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2549 if (fs.f_flags & MNT_NOEXEC) {
2550 _rtld_error("Cannot execute objects on %s", fs.f_mntonname);
2554 dbg("loading \"%s\"", printable_path(path));
2555 obj = map_object(fd, printable_path(path), sbp);
2560 * If DT_SONAME is present in the object, digest_dynamic2 already
2561 * added it to the object names.
2564 object_add_name(obj, name);
2566 if (!digest_dynamic(obj, 0))
2568 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2569 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2570 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) {
2571 dbg("refusing to load PIE executable \"%s\"", obj->path);
2572 _rtld_error("Cannot load PIE binary %s as DSO", obj->path);
2575 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2577 dbg("refusing to load non-loadable \"%s\"", obj->path);
2578 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2582 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2583 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2586 linkmap_add(obj); /* for GDB & dlinfo() */
2587 max_stack_flags |= obj->stack_flags;
2589 dbg(" %p .. %p: %s", obj->mapbase,
2590 obj->mapbase + obj->mapsize - 1, obj->path);
2592 dbg(" WARNING: %s has impure text", obj->path);
2593 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2599 munmap(obj->mapbase, obj->mapsize);
2605 obj_from_addr(const void *addr)
2609 TAILQ_FOREACH(obj, &obj_list, next) {
2612 if (addr < (void *) obj->mapbase)
2614 if (addr < (void *)(obj->mapbase + obj->mapsize))
2623 Elf_Addr *preinit_addr;
2626 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2627 if (preinit_addr == NULL)
2630 for (index = 0; index < obj_main->preinit_array_num; index++) {
2631 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2632 dbg("calling preinit function for %s at %p", obj_main->path,
2633 (void *)preinit_addr[index]);
2634 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2635 0, 0, obj_main->path);
2636 call_init_pointer(obj_main, preinit_addr[index]);
2642 * Call the finalization functions for each of the objects in "list"
2643 * belonging to the DAG of "root" and referenced once. If NULL "root"
2644 * is specified, every finalization function will be called regardless
2645 * of the reference count and the list elements won't be freed. All of
2646 * the objects are expected to have non-NULL fini functions.
2649 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2653 Elf_Addr *fini_addr;
2656 assert(root == NULL || root->refcount == 1);
2659 root->doomed = true;
2662 * Preserve the current error message since a fini function might
2663 * call into the dynamic linker and overwrite it.
2665 saved_msg = errmsg_save();
2667 STAILQ_FOREACH(elm, list, link) {
2668 if (root != NULL && (elm->obj->refcount != 1 ||
2669 objlist_find(&root->dagmembers, elm->obj) == NULL))
2671 /* Remove object from fini list to prevent recursive invocation. */
2672 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2673 /* Ensure that new references cannot be acquired. */
2674 elm->obj->doomed = true;
2676 hold_object(elm->obj);
2677 lock_release(rtld_bind_lock, lockstate);
2679 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2680 * When this happens, DT_FINI_ARRAY is processed first.
2682 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2683 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2684 for (index = elm->obj->fini_array_num - 1; index >= 0;
2686 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2687 dbg("calling fini function for %s at %p",
2688 elm->obj->path, (void *)fini_addr[index]);
2689 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2690 (void *)fini_addr[index], 0, 0, elm->obj->path);
2691 call_initfini_pointer(elm->obj, fini_addr[index]);
2695 if (elm->obj->fini != (Elf_Addr)NULL) {
2696 dbg("calling fini function for %s at %p", elm->obj->path,
2697 (void *)elm->obj->fini);
2698 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2699 0, 0, elm->obj->path);
2700 call_initfini_pointer(elm->obj, elm->obj->fini);
2702 wlock_acquire(rtld_bind_lock, lockstate);
2703 unhold_object(elm->obj);
2704 /* No need to free anything if process is going down. */
2708 * We must restart the list traversal after every fini call
2709 * because a dlclose() call from the fini function or from
2710 * another thread might have modified the reference counts.
2714 } while (elm != NULL);
2715 errmsg_restore(saved_msg);
2719 * Call the initialization functions for each of the objects in
2720 * "list". All of the objects are expected to have non-NULL init
2724 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2729 Elf_Addr *init_addr;
2730 void (*reg)(void (*)(void));
2734 * Clean init_scanned flag so that objects can be rechecked and
2735 * possibly initialized earlier if any of vectors called below
2736 * cause the change by using dlopen.
2738 TAILQ_FOREACH(obj, &obj_list, next) {
2741 obj->init_scanned = false;
2745 * Preserve the current error message since an init function might
2746 * call into the dynamic linker and overwrite it.
2748 saved_msg = errmsg_save();
2749 STAILQ_FOREACH(elm, list, link) {
2750 if (elm->obj->init_done) /* Initialized early. */
2753 * Race: other thread might try to use this object before current
2754 * one completes the initialization. Not much can be done here
2755 * without better locking.
2757 elm->obj->init_done = true;
2758 hold_object(elm->obj);
2760 if (elm->obj == obj_main && obj_main->crt_no_init) {
2761 reg = (void (*)(void (*)(void)))get_program_var_addr(
2762 "__libc_atexit", lockstate);
2764 lock_release(rtld_bind_lock, lockstate);
2767 rtld_exit_ptr = rtld_nop_exit;
2771 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2772 * When this happens, DT_INIT is processed first.
2774 if (elm->obj->init != (Elf_Addr)NULL) {
2775 dbg("calling init function for %s at %p", elm->obj->path,
2776 (void *)elm->obj->init);
2777 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2778 0, 0, elm->obj->path);
2779 call_initfini_pointer(elm->obj, elm->obj->init);
2781 init_addr = (Elf_Addr *)elm->obj->init_array;
2782 if (init_addr != NULL) {
2783 for (index = 0; index < elm->obj->init_array_num; index++) {
2784 if (init_addr[index] != 0 && init_addr[index] != 1) {
2785 dbg("calling init function for %s at %p", elm->obj->path,
2786 (void *)init_addr[index]);
2787 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2788 (void *)init_addr[index], 0, 0, elm->obj->path);
2789 call_init_pointer(elm->obj, init_addr[index]);
2793 wlock_acquire(rtld_bind_lock, lockstate);
2794 unhold_object(elm->obj);
2796 errmsg_restore(saved_msg);
2800 objlist_clear(Objlist *list)
2804 while (!STAILQ_EMPTY(list)) {
2805 elm = STAILQ_FIRST(list);
2806 STAILQ_REMOVE_HEAD(list, link);
2811 static Objlist_Entry *
2812 objlist_find(Objlist *list, const Obj_Entry *obj)
2816 STAILQ_FOREACH(elm, list, link)
2817 if (elm->obj == obj)
2823 objlist_init(Objlist *list)
2829 objlist_push_head(Objlist *list, Obj_Entry *obj)
2833 elm = NEW(Objlist_Entry);
2835 STAILQ_INSERT_HEAD(list, elm, link);
2839 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2843 elm = NEW(Objlist_Entry);
2845 STAILQ_INSERT_TAIL(list, elm, link);
2849 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2851 Objlist_Entry *elm, *listelm;
2853 STAILQ_FOREACH(listelm, list, link) {
2854 if (listelm->obj == listobj)
2857 elm = NEW(Objlist_Entry);
2859 if (listelm != NULL)
2860 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2862 STAILQ_INSERT_TAIL(list, elm, link);
2866 objlist_remove(Objlist *list, Obj_Entry *obj)
2870 if ((elm = objlist_find(list, obj)) != NULL) {
2871 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2877 * Relocate dag rooted in the specified object.
2878 * Returns 0 on success, or -1 on failure.
2882 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2883 int flags, RtldLockState *lockstate)
2889 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2890 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2899 * Prepare for, or clean after, relocating an object marked with
2900 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
2901 * segments are remapped read-write. After relocations are done, the
2902 * segment's permissions are returned back to the modes specified in
2903 * the phdrs. If any relocation happened, or always for wired
2904 * program, COW is triggered.
2907 reloc_textrel_prot(Obj_Entry *obj, bool before)
2914 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
2916 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
2918 base = obj->relocbase + trunc_page(ph->p_vaddr);
2919 sz = round_page(ph->p_vaddr + ph->p_filesz) -
2920 trunc_page(ph->p_vaddr);
2921 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0);
2922 if (mprotect(base, sz, prot) == -1) {
2923 _rtld_error("%s: Cannot write-%sable text segment: %s",
2924 obj->path, before ? "en" : "dis",
2925 rtld_strerror(errno));
2933 * Relocate single object.
2934 * Returns 0 on success, or -1 on failure.
2937 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2938 int flags, RtldLockState *lockstate)
2943 obj->relocated = true;
2945 dbg("relocating \"%s\"", obj->path);
2947 if (obj->symtab == NULL || obj->strtab == NULL ||
2948 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2949 _rtld_error("%s: Shared object has no run-time symbol table",
2954 /* There are relocations to the write-protected text segment. */
2955 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
2958 /* Process the non-PLT non-IFUNC relocations. */
2959 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2962 /* Re-protected the text segment. */
2963 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
2966 /* Set the special PLT or GOT entries. */
2969 /* Process the PLT relocations. */
2970 if (reloc_plt(obj, flags, lockstate) == -1)
2972 /* Relocate the jump slots if we are doing immediate binding. */
2973 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags,
2977 if (!obj->mainprog && obj_enforce_relro(obj) == -1)
2981 * Set up the magic number and version in the Obj_Entry. These
2982 * were checked in the crt1.o from the original ElfKit, so we
2983 * set them for backward compatibility.
2985 obj->magic = RTLD_MAGIC;
2986 obj->version = RTLD_VERSION;
2992 * Relocate newly-loaded shared objects. The argument is a pointer to
2993 * the Obj_Entry for the first such object. All objects from the first
2994 * to the end of the list of objects are relocated. Returns 0 on success,
2998 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2999 int flags, RtldLockState *lockstate)
3004 for (error = 0, obj = first; obj != NULL;
3005 obj = TAILQ_NEXT(obj, next)) {
3008 error = relocate_object(obj, bind_now, rtldobj, flags,
3017 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
3018 * referencing STT_GNU_IFUNC symbols is postponed till the other
3019 * relocations are done. The indirect functions specified as
3020 * ifunc are allowed to call other symbols, so we need to have
3021 * objects relocated before asking for resolution from indirects.
3023 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
3024 * instead of the usual lazy handling of PLT slots. It is
3025 * consistent with how GNU does it.
3028 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
3029 RtldLockState *lockstate)
3032 if (obj->ifuncs_resolved)
3034 obj->ifuncs_resolved = true;
3035 if (!obj->irelative && !obj->irelative_nonplt &&
3036 !((obj->bind_now || bind_now) && obj->gnu_ifunc))
3038 if (obj_disable_relro(obj) == -1 ||
3039 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) ||
3040 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj,
3041 lockstate) == -1) ||
3042 ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
3043 reloc_gnu_ifunc(obj, flags, lockstate) == -1) ||
3044 obj_enforce_relro(obj) == -1)
3050 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
3051 RtldLockState *lockstate)
3056 STAILQ_FOREACH(elm, list, link) {
3060 if (resolve_object_ifunc(obj, bind_now, flags,
3068 * Cleanup procedure. It will be called (by the atexit mechanism) just
3069 * before the process exits.
3074 RtldLockState lockstate;
3076 wlock_acquire(rtld_bind_lock, &lockstate);
3078 objlist_call_fini(&list_fini, NULL, &lockstate);
3079 /* No need to remove the items from the list, since we are exiting. */
3080 if (!libmap_disable)
3082 lock_release(rtld_bind_lock, &lockstate);
3091 * Iterate over a search path, translate each element, and invoke the
3092 * callback on the result.
3095 path_enumerate(const char *path, path_enum_proc callback,
3096 const char *refobj_path, void *arg)
3102 path += strspn(path, ":;");
3103 while (*path != '\0') {
3107 len = strcspn(path, ":;");
3108 trans = lm_findn(refobj_path, path, len);
3110 res = callback(trans, strlen(trans), arg);
3112 res = callback(path, len, arg);
3118 path += strspn(path, ":;");
3124 struct try_library_args {
3133 try_library_path(const char *dir, size_t dirlen, void *param)
3135 struct try_library_args *arg;
3139 if (*dir == '/' || trust) {
3142 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3145 pathname = arg->buffer;
3146 strncpy(pathname, dir, dirlen);
3147 pathname[dirlen] = '/';
3148 strcpy(pathname + dirlen + 1, arg->name);
3150 dbg(" Trying \"%s\"", pathname);
3151 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3153 dbg(" Opened \"%s\", fd %d", pathname, fd);
3154 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3155 strcpy(pathname, arg->buffer);
3159 dbg(" Failed to open \"%s\": %s",
3160 pathname, rtld_strerror(errno));
3167 search_library_path(const char *name, const char *path,
3168 const char *refobj_path, int *fdp)
3171 struct try_library_args arg;
3177 arg.namelen = strlen(name);
3178 arg.buffer = xmalloc(PATH_MAX);
3179 arg.buflen = PATH_MAX;
3182 p = path_enumerate(path, try_library_path, refobj_path, &arg);
3192 * Finds the library with the given name using the directory descriptors
3193 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3195 * Returns a freshly-opened close-on-exec file descriptor for the library,
3196 * or -1 if the library cannot be found.
3199 search_library_pathfds(const char *name, const char *path, int *fdp)
3201 char *envcopy, *fdstr, *found, *last_token;
3205 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3207 /* Don't load from user-specified libdirs into setuid binaries. */
3211 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3215 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3216 if (name[0] == '/') {
3217 dbg("Absolute path (%s) passed to %s", name, __func__);
3222 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3223 * copy of the path, as strtok_r rewrites separator tokens
3227 envcopy = xstrdup(path);
3228 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3229 fdstr = strtok_r(NULL, ":", &last_token)) {
3230 dirfd = parse_integer(fdstr);
3232 _rtld_error("failed to parse directory FD: '%s'",
3236 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3239 len = strlen(fdstr) + strlen(name) + 3;
3240 found = xmalloc(len);
3241 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
3242 _rtld_error("error generating '%d/%s'",
3246 dbg("open('%s') => %d", found, fd);
3257 dlclose(void *handle)
3259 RtldLockState lockstate;
3262 wlock_acquire(rtld_bind_lock, &lockstate);
3263 error = dlclose_locked(handle, &lockstate);
3264 lock_release(rtld_bind_lock, &lockstate);
3269 dlclose_locked(void *handle, RtldLockState *lockstate)
3273 root = dlcheck(handle);
3276 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3279 /* Unreference the object and its dependencies. */
3280 root->dl_refcount--;
3282 if (root->refcount == 1) {
3284 * The object will be no longer referenced, so we must unload it.
3285 * First, call the fini functions.
3287 objlist_call_fini(&list_fini, root, lockstate);
3291 /* Finish cleaning up the newly-unreferenced objects. */
3292 GDB_STATE(RT_DELETE,&root->linkmap);
3293 unload_object(root, lockstate);
3294 GDB_STATE(RT_CONSISTENT,NULL);
3298 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3305 char *msg = error_message;
3306 error_message = NULL;
3311 * This function is deprecated and has no effect.
3314 dllockinit(void *context,
3315 void *(*_lock_create)(void *context) __unused,
3316 void (*_rlock_acquire)(void *lock) __unused,
3317 void (*_wlock_acquire)(void *lock) __unused,
3318 void (*_lock_release)(void *lock) __unused,
3319 void (*_lock_destroy)(void *lock) __unused,
3320 void (*context_destroy)(void *context))
3322 static void *cur_context;
3323 static void (*cur_context_destroy)(void *);
3325 /* Just destroy the context from the previous call, if necessary. */
3326 if (cur_context_destroy != NULL)
3327 cur_context_destroy(cur_context);
3328 cur_context = context;
3329 cur_context_destroy = context_destroy;
3333 dlopen(const char *name, int mode)
3336 return (rtld_dlopen(name, -1, mode));
3340 fdlopen(int fd, int mode)
3343 return (rtld_dlopen(NULL, fd, mode));
3347 rtld_dlopen(const char *name, int fd, int mode)
3349 RtldLockState lockstate;
3352 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3353 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3354 if (ld_tracing != NULL) {
3355 rlock_acquire(rtld_bind_lock, &lockstate);
3356 if (sigsetjmp(lockstate.env, 0) != 0)
3357 lock_upgrade(rtld_bind_lock, &lockstate);
3358 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate));
3359 lock_release(rtld_bind_lock, &lockstate);
3361 lo_flags = RTLD_LO_DLOPEN;
3362 if (mode & RTLD_NODELETE)
3363 lo_flags |= RTLD_LO_NODELETE;
3364 if (mode & RTLD_NOLOAD)
3365 lo_flags |= RTLD_LO_NOLOAD;
3366 if (mode & RTLD_DEEPBIND)
3367 lo_flags |= RTLD_LO_DEEPBIND;
3368 if (ld_tracing != NULL)
3369 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS;
3371 return (dlopen_object(name, fd, obj_main, lo_flags,
3372 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3376 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3381 if (obj->refcount == 0)
3382 unload_object(obj, lockstate);
3386 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3387 int mode, RtldLockState *lockstate)
3389 Obj_Entry *old_obj_tail;
3392 RtldLockState mlockstate;
3395 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x",
3396 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" :
3397 refobj->path, lo_flags, mode);
3398 objlist_init(&initlist);
3400 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3401 wlock_acquire(rtld_bind_lock, &mlockstate);
3402 lockstate = &mlockstate;
3404 GDB_STATE(RT_ADD,NULL);
3406 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
3408 if (name == NULL && fd == -1) {
3412 obj = load_object(name, fd, refobj, lo_flags);
3417 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3418 objlist_push_tail(&list_global, obj);
3419 if (globallist_next(old_obj_tail) != NULL) {
3420 /* We loaded something new. */
3421 assert(globallist_next(old_obj_tail) == obj);
3422 if ((lo_flags & RTLD_LO_DEEPBIND) != 0)
3423 obj->symbolic = true;
3425 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 &&
3426 obj->static_tls && !allocate_tls_offset(obj)) {
3427 _rtld_error("%s: No space available "
3428 "for static Thread Local Storage", obj->path);
3432 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN |
3433 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE));
3437 result = rtld_verify_versions(&obj->dagmembers);
3438 if (result != -1 && ld_tracing)
3440 if (result == -1 || relocate_object_dag(obj,
3441 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3442 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3444 dlopen_cleanup(obj, lockstate);
3446 } else if (lo_flags & RTLD_LO_EARLY) {
3448 * Do not call the init functions for early loaded
3449 * filtees. The image is still not initialized enough
3452 * Our object is found by the global object list and
3453 * will be ordered among all init calls done right
3454 * before transferring control to main.
3457 /* Make list of init functions to call. */
3458 initlist_add_objects(obj, obj, &initlist);
3461 * Process all no_delete or global objects here, given
3462 * them own DAGs to prevent their dependencies from being
3463 * unloaded. This has to be done after we have loaded all
3464 * of the dependencies, so that we do not miss any.
3470 * Bump the reference counts for objects on this DAG. If
3471 * this is the first dlopen() call for the object that was
3472 * already loaded as a dependency, initialize the dag
3478 if ((lo_flags & RTLD_LO_TRACE) != 0)
3481 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3482 obj->z_nodelete) && !obj->ref_nodel) {
3483 dbg("obj %s nodelete", obj->path);
3485 obj->z_nodelete = obj->ref_nodel = true;
3489 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3491 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3493 if ((lo_flags & RTLD_LO_EARLY) == 0) {
3494 map_stacks_exec(lockstate);
3496 distribute_static_tls(&initlist, lockstate);
3499 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3500 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3502 objlist_clear(&initlist);
3503 dlopen_cleanup(obj, lockstate);
3504 if (lockstate == &mlockstate)
3505 lock_release(rtld_bind_lock, lockstate);
3509 if (!(lo_flags & RTLD_LO_EARLY)) {
3510 /* Call the init functions. */
3511 objlist_call_init(&initlist, lockstate);
3513 objlist_clear(&initlist);
3514 if (lockstate == &mlockstate)
3515 lock_release(rtld_bind_lock, lockstate);
3518 trace_loaded_objects(obj);
3519 if (lockstate == &mlockstate)
3520 lock_release(rtld_bind_lock, lockstate);
3525 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3529 const Obj_Entry *obj, *defobj;
3532 RtldLockState lockstate;
3539 symlook_init(&req, name);
3541 req.flags = flags | SYMLOOK_IN_PLT;
3542 req.lockstate = &lockstate;
3544 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3545 rlock_acquire(rtld_bind_lock, &lockstate);
3546 if (sigsetjmp(lockstate.env, 0) != 0)
3547 lock_upgrade(rtld_bind_lock, &lockstate);
3548 if (handle == NULL || handle == RTLD_NEXT ||
3549 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3551 if ((obj = obj_from_addr(retaddr)) == NULL) {
3552 _rtld_error("Cannot determine caller's shared object");
3553 lock_release(rtld_bind_lock, &lockstate);
3554 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3557 if (handle == NULL) { /* Just the caller's shared object. */
3558 res = symlook_obj(&req, obj);
3561 defobj = req.defobj_out;
3563 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3564 handle == RTLD_SELF) { /* ... caller included */
3565 if (handle == RTLD_NEXT)
3566 obj = globallist_next(obj);
3567 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3570 res = symlook_obj(&req, obj);
3573 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3575 defobj = req.defobj_out;
3576 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3582 * Search the dynamic linker itself, and possibly resolve the
3583 * symbol from there. This is how the application links to
3584 * dynamic linker services such as dlopen.
3586 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3587 res = symlook_obj(&req, &obj_rtld);
3590 defobj = req.defobj_out;
3594 assert(handle == RTLD_DEFAULT);
3595 res = symlook_default(&req, obj);
3597 defobj = req.defobj_out;
3602 if ((obj = dlcheck(handle)) == NULL) {
3603 lock_release(rtld_bind_lock, &lockstate);
3604 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3608 donelist_init(&donelist);
3609 if (obj->mainprog) {
3610 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3611 res = symlook_global(&req, &donelist);
3614 defobj = req.defobj_out;
3617 * Search the dynamic linker itself, and possibly resolve the
3618 * symbol from there. This is how the application links to
3619 * dynamic linker services such as dlopen.
3621 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3622 res = symlook_obj(&req, &obj_rtld);
3625 defobj = req.defobj_out;
3630 /* Search the whole DAG rooted at the given object. */
3631 res = symlook_list(&req, &obj->dagmembers, &donelist);
3634 defobj = req.defobj_out;
3640 lock_release(rtld_bind_lock, &lockstate);
3643 * The value required by the caller is derived from the value
3644 * of the symbol. this is simply the relocated value of the
3647 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3648 sym = make_function_pointer(def, defobj);
3649 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3650 sym = rtld_resolve_ifunc(defobj, def);
3651 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3652 ti.ti_module = defobj->tlsindex;
3653 ti.ti_offset = def->st_value;
3654 sym = __tls_get_addr(&ti);
3656 sym = defobj->relocbase + def->st_value;
3657 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3661 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
3662 ve != NULL ? ve->name : "");
3663 lock_release(rtld_bind_lock, &lockstate);
3664 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3669 dlsym(void *handle, const char *name)
3671 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3676 dlfunc(void *handle, const char *name)
3683 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3689 dlvsym(void *handle, const char *name, const char *version)
3693 ventry.name = version;
3695 ventry.hash = elf_hash(version);
3697 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3702 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3704 const Obj_Entry *obj;
3705 RtldLockState lockstate;
3707 rlock_acquire(rtld_bind_lock, &lockstate);
3708 obj = obj_from_addr(addr);
3710 _rtld_error("No shared object contains address");
3711 lock_release(rtld_bind_lock, &lockstate);
3714 rtld_fill_dl_phdr_info(obj, phdr_info);
3715 lock_release(rtld_bind_lock, &lockstate);
3720 dladdr(const void *addr, Dl_info *info)
3722 const Obj_Entry *obj;
3725 unsigned long symoffset;
3726 RtldLockState lockstate;
3728 rlock_acquire(rtld_bind_lock, &lockstate);
3729 obj = obj_from_addr(addr);
3731 _rtld_error("No shared object contains address");
3732 lock_release(rtld_bind_lock, &lockstate);
3735 info->dli_fname = obj->path;
3736 info->dli_fbase = obj->mapbase;
3737 info->dli_saddr = (void *)0;
3738 info->dli_sname = NULL;
3741 * Walk the symbol list looking for the symbol whose address is
3742 * closest to the address sent in.
3744 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3745 def = obj->symtab + symoffset;
3748 * For skip the symbol if st_shndx is either SHN_UNDEF or
3751 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3755 * If the symbol is greater than the specified address, or if it
3756 * is further away from addr than the current nearest symbol,
3759 symbol_addr = obj->relocbase + def->st_value;
3760 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3763 /* Update our idea of the nearest symbol. */
3764 info->dli_sname = obj->strtab + def->st_name;
3765 info->dli_saddr = symbol_addr;
3768 if (info->dli_saddr == addr)
3771 lock_release(rtld_bind_lock, &lockstate);
3776 dlinfo(void *handle, int request, void *p)
3778 const Obj_Entry *obj;
3779 RtldLockState lockstate;
3782 rlock_acquire(rtld_bind_lock, &lockstate);
3784 if (handle == NULL || handle == RTLD_SELF) {
3787 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3788 if ((obj = obj_from_addr(retaddr)) == NULL)
3789 _rtld_error("Cannot determine caller's shared object");
3791 obj = dlcheck(handle);
3794 lock_release(rtld_bind_lock, &lockstate);
3800 case RTLD_DI_LINKMAP:
3801 *((struct link_map const **)p) = &obj->linkmap;
3803 case RTLD_DI_ORIGIN:
3804 error = rtld_dirname(obj->path, p);
3807 case RTLD_DI_SERINFOSIZE:
3808 case RTLD_DI_SERINFO:
3809 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3813 _rtld_error("Invalid request %d passed to dlinfo()", request);
3817 lock_release(rtld_bind_lock, &lockstate);
3823 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3826 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3827 phdr_info->dlpi_name = obj->path;
3828 phdr_info->dlpi_phdr = obj->phdr;
3829 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3830 phdr_info->dlpi_tls_modid = obj->tlsindex;
3831 phdr_info->dlpi_tls_data = obj->tlsinit;
3832 phdr_info->dlpi_adds = obj_loads;
3833 phdr_info->dlpi_subs = obj_loads - obj_count;
3837 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3839 struct dl_phdr_info phdr_info;
3840 Obj_Entry *obj, marker;
3841 RtldLockState bind_lockstate, phdr_lockstate;
3844 init_marker(&marker);
3847 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3848 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3849 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
3850 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
3851 rtld_fill_dl_phdr_info(obj, &phdr_info);
3853 lock_release(rtld_bind_lock, &bind_lockstate);
3855 error = callback(&phdr_info, sizeof phdr_info, param);
3857 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3859 obj = globallist_next(&marker);
3860 TAILQ_REMOVE(&obj_list, &marker, next);
3862 lock_release(rtld_bind_lock, &bind_lockstate);
3863 lock_release(rtld_phdr_lock, &phdr_lockstate);
3869 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3870 lock_release(rtld_bind_lock, &bind_lockstate);
3871 error = callback(&phdr_info, sizeof(phdr_info), param);
3873 lock_release(rtld_phdr_lock, &phdr_lockstate);
3878 fill_search_info(const char *dir, size_t dirlen, void *param)
3880 struct fill_search_info_args *arg;
3884 if (arg->request == RTLD_DI_SERINFOSIZE) {
3885 arg->serinfo->dls_cnt ++;
3886 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3888 struct dl_serpath *s_entry;
3890 s_entry = arg->serpath;
3891 s_entry->dls_name = arg->strspace;
3892 s_entry->dls_flags = arg->flags;
3894 strncpy(arg->strspace, dir, dirlen);
3895 arg->strspace[dirlen] = '\0';
3897 arg->strspace += dirlen + 1;
3905 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3907 struct dl_serinfo _info;
3908 struct fill_search_info_args args;
3910 args.request = RTLD_DI_SERINFOSIZE;
3911 args.serinfo = &_info;
3913 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3916 path_enumerate(obj->rpath, fill_search_info, NULL, &args);
3917 path_enumerate(ld_library_path, fill_search_info, NULL, &args);
3918 path_enumerate(obj->runpath, fill_search_info, NULL, &args);
3919 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args);
3920 if (!obj->z_nodeflib)
3921 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args);
3924 if (request == RTLD_DI_SERINFOSIZE) {
3925 info->dls_size = _info.dls_size;
3926 info->dls_cnt = _info.dls_cnt;
3930 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3931 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3935 args.request = RTLD_DI_SERINFO;
3936 args.serinfo = info;
3937 args.serpath = &info->dls_serpath[0];
3938 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3940 args.flags = LA_SER_RUNPATH;
3941 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL)
3944 args.flags = LA_SER_LIBPATH;
3945 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL)
3948 args.flags = LA_SER_RUNPATH;
3949 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL)
3952 args.flags = LA_SER_CONFIG;
3953 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args)
3957 args.flags = LA_SER_DEFAULT;
3958 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path,
3959 fill_search_info, NULL, &args) != NULL)
3965 rtld_dirname(const char *path, char *bname)
3969 /* Empty or NULL string gets treated as "." */
3970 if (path == NULL || *path == '\0') {
3976 /* Strip trailing slashes */
3977 endp = path + strlen(path) - 1;
3978 while (endp > path && *endp == '/')
3981 /* Find the start of the dir */
3982 while (endp > path && *endp != '/')
3985 /* Either the dir is "/" or there are no slashes */
3987 bname[0] = *endp == '/' ? '/' : '.';
3993 } while (endp > path && *endp == '/');
3996 if (endp - path + 2 > PATH_MAX)
3998 _rtld_error("Filename is too long: %s", path);
4002 strncpy(bname, path, endp - path + 1);
4003 bname[endp - path + 1] = '\0';
4008 rtld_dirname_abs(const char *path, char *base)
4012 if (realpath(path, base) == NULL) {
4013 _rtld_error("realpath \"%s\" failed (%s)", path,
4014 rtld_strerror(errno));
4017 dbg("%s -> %s", path, base);
4018 last = strrchr(base, '/');
4020 _rtld_error("non-abs result from realpath \"%s\"", path);
4029 linkmap_add(Obj_Entry *obj)
4031 struct link_map *l, *prev;
4034 l->l_name = obj->path;
4035 l->l_base = obj->mapbase;
4036 l->l_ld = obj->dynamic;
4037 l->l_addr = obj->relocbase;
4039 if (r_debug.r_map == NULL) {
4045 * Scan to the end of the list, but not past the entry for the
4046 * dynamic linker, which we want to keep at the very end.
4048 for (prev = r_debug.r_map;
4049 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
4050 prev = prev->l_next)
4053 /* Link in the new entry. */
4055 l->l_next = prev->l_next;
4056 if (l->l_next != NULL)
4057 l->l_next->l_prev = l;
4062 linkmap_delete(Obj_Entry *obj)
4067 if (l->l_prev == NULL) {
4068 if ((r_debug.r_map = l->l_next) != NULL)
4069 l->l_next->l_prev = NULL;
4073 if ((l->l_prev->l_next = l->l_next) != NULL)
4074 l->l_next->l_prev = l->l_prev;
4078 * Function for the debugger to set a breakpoint on to gain control.
4080 * The two parameters allow the debugger to easily find and determine
4081 * what the runtime loader is doing and to whom it is doing it.
4083 * When the loadhook trap is hit (r_debug_state, set at program
4084 * initialization), the arguments can be found on the stack:
4086 * +8 struct link_map *m
4087 * +4 struct r_debug *rd
4091 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused)
4094 * The following is a hack to force the compiler to emit calls to
4095 * this function, even when optimizing. If the function is empty,
4096 * the compiler is not obliged to emit any code for calls to it,
4097 * even when marked __noinline. However, gdb depends on those
4100 __compiler_membar();
4104 * A function called after init routines have completed. This can be used to
4105 * break before a program's entry routine is called, and can be used when
4106 * main is not available in the symbol table.
4109 _r_debug_postinit(struct link_map *m __unused)
4112 /* See r_debug_state(). */
4113 __compiler_membar();
4117 release_object(Obj_Entry *obj)
4120 if (obj->holdcount > 0) {
4121 obj->unholdfree = true;
4124 munmap(obj->mapbase, obj->mapsize);
4125 linkmap_delete(obj);
4130 * Get address of the pointer variable in the main program.
4131 * Prefer non-weak symbol over the weak one.
4133 static const void **
4134 get_program_var_addr(const char *name, RtldLockState *lockstate)
4139 symlook_init(&req, name);
4140 req.lockstate = lockstate;
4141 donelist_init(&donelist);
4142 if (symlook_global(&req, &donelist) != 0)
4144 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4145 return ((const void **)make_function_pointer(req.sym_out,
4147 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4148 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
4150 return ((const void **)(req.defobj_out->relocbase +
4151 req.sym_out->st_value));
4155 * Set a pointer variable in the main program to the given value. This
4156 * is used to set key variables such as "environ" before any of the
4157 * init functions are called.
4160 set_program_var(const char *name, const void *value)
4164 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4165 dbg("\"%s\": *%p <-- %p", name, addr, value);
4171 * Search the global objects, including dependencies and main object,
4172 * for the given symbol.
4175 symlook_global(SymLook *req, DoneList *donelist)
4178 const Objlist_Entry *elm;
4181 symlook_init_from_req(&req1, req);
4183 /* Search all objects loaded at program start up. */
4184 if (req->defobj_out == NULL ||
4185 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4186 res = symlook_list(&req1, &list_main, donelist);
4187 if (res == 0 && (req->defobj_out == NULL ||
4188 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4189 req->sym_out = req1.sym_out;
4190 req->defobj_out = req1.defobj_out;
4191 assert(req->defobj_out != NULL);
4195 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4196 STAILQ_FOREACH(elm, &list_global, link) {
4197 if (req->defobj_out != NULL &&
4198 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4200 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4201 if (res == 0 && (req->defobj_out == NULL ||
4202 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4203 req->sym_out = req1.sym_out;
4204 req->defobj_out = req1.defobj_out;
4205 assert(req->defobj_out != NULL);
4209 return (req->sym_out != NULL ? 0 : ESRCH);
4213 * Given a symbol name in a referencing object, find the corresponding
4214 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4215 * no definition was found. Returns a pointer to the Obj_Entry of the
4216 * defining object via the reference parameter DEFOBJ_OUT.
4219 symlook_default(SymLook *req, const Obj_Entry *refobj)
4222 const Objlist_Entry *elm;
4226 donelist_init(&donelist);
4227 symlook_init_from_req(&req1, req);
4230 * Look first in the referencing object if linked symbolically,
4231 * and similarly handle protected symbols.
4233 res = symlook_obj(&req1, refobj);
4234 if (res == 0 && (refobj->symbolic ||
4235 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) {
4236 req->sym_out = req1.sym_out;
4237 req->defobj_out = req1.defobj_out;
4238 assert(req->defobj_out != NULL);
4240 if (refobj->symbolic || req->defobj_out != NULL)
4241 donelist_check(&donelist, refobj);
4243 symlook_global(req, &donelist);
4245 /* Search all dlopened DAGs containing the referencing object. */
4246 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4247 if (req->sym_out != NULL &&
4248 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4250 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4251 if (res == 0 && (req->sym_out == NULL ||
4252 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4253 req->sym_out = req1.sym_out;
4254 req->defobj_out = req1.defobj_out;
4255 assert(req->defobj_out != NULL);
4260 * Search the dynamic linker itself, and possibly resolve the
4261 * symbol from there. This is how the application links to
4262 * dynamic linker services such as dlopen.
4264 if (req->sym_out == NULL ||
4265 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4266 res = symlook_obj(&req1, &obj_rtld);
4268 req->sym_out = req1.sym_out;
4269 req->defobj_out = req1.defobj_out;
4270 assert(req->defobj_out != NULL);
4274 return (req->sym_out != NULL ? 0 : ESRCH);
4278 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4281 const Obj_Entry *defobj;
4282 const Objlist_Entry *elm;
4288 STAILQ_FOREACH(elm, objlist, link) {
4289 if (donelist_check(dlp, elm->obj))
4291 symlook_init_from_req(&req1, req);
4292 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4293 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4295 defobj = req1.defobj_out;
4296 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4303 req->defobj_out = defobj;
4310 * Search the chain of DAGS cointed to by the given Needed_Entry
4311 * for a symbol of the given name. Each DAG is scanned completely
4312 * before advancing to the next one. Returns a pointer to the symbol,
4313 * or NULL if no definition was found.
4316 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4319 const Needed_Entry *n;
4320 const Obj_Entry *defobj;
4326 symlook_init_from_req(&req1, req);
4327 for (n = needed; n != NULL; n = n->next) {
4328 if (n->obj == NULL ||
4329 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
4331 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4333 defobj = req1.defobj_out;
4334 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4340 req->defobj_out = defobj;
4347 * Search the symbol table of a single shared object for a symbol of
4348 * the given name and version, if requested. Returns a pointer to the
4349 * symbol, or NULL if no definition was found. If the object is
4350 * filter, return filtered symbol from filtee.
4352 * The symbol's hash value is passed in for efficiency reasons; that
4353 * eliminates many recomputations of the hash value.
4356 symlook_obj(SymLook *req, const Obj_Entry *obj)
4360 int flags, res, mres;
4363 * If there is at least one valid hash at this point, we prefer to
4364 * use the faster GNU version if available.
4366 if (obj->valid_hash_gnu)
4367 mres = symlook_obj1_gnu(req, obj);
4368 else if (obj->valid_hash_sysv)
4369 mres = symlook_obj1_sysv(req, obj);
4374 if (obj->needed_filtees != NULL) {
4375 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4376 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4377 donelist_init(&donelist);
4378 symlook_init_from_req(&req1, req);
4379 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
4381 req->sym_out = req1.sym_out;
4382 req->defobj_out = req1.defobj_out;
4386 if (obj->needed_aux_filtees != NULL) {
4387 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4388 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4389 donelist_init(&donelist);
4390 symlook_init_from_req(&req1, req);
4391 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
4393 req->sym_out = req1.sym_out;
4394 req->defobj_out = req1.defobj_out;
4402 /* Symbol match routine common to both hash functions */
4404 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4405 const unsigned long symnum)
4408 const Elf_Sym *symp;
4411 symp = obj->symtab + symnum;
4412 strp = obj->strtab + symp->st_name;
4414 switch (ELF_ST_TYPE(symp->st_info)) {
4420 if (symp->st_value == 0)
4424 if (symp->st_shndx != SHN_UNDEF)
4427 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4428 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4435 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4438 if (req->ventry == NULL) {
4439 if (obj->versyms != NULL) {
4440 verndx = VER_NDX(obj->versyms[symnum]);
4441 if (verndx > obj->vernum) {
4443 "%s: symbol %s references wrong version %d",
4444 obj->path, obj->strtab + symnum, verndx);
4448 * If we are not called from dlsym (i.e. this
4449 * is a normal relocation from unversioned
4450 * binary), accept the symbol immediately if
4451 * it happens to have first version after this
4452 * shared object became versioned. Otherwise,
4453 * if symbol is versioned and not hidden,
4454 * remember it. If it is the only symbol with
4455 * this name exported by the shared object, it
4456 * will be returned as a match by the calling
4457 * function. If symbol is global (verndx < 2)
4458 * accept it unconditionally.
4460 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4461 verndx == VER_NDX_GIVEN) {
4462 result->sym_out = symp;
4465 else if (verndx >= VER_NDX_GIVEN) {
4466 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4468 if (result->vsymp == NULL)
4469 result->vsymp = symp;
4475 result->sym_out = symp;
4478 if (obj->versyms == NULL) {
4479 if (object_match_name(obj, req->ventry->name)) {
4480 _rtld_error("%s: object %s should provide version %s "
4481 "for symbol %s", obj_rtld.path, obj->path,
4482 req->ventry->name, obj->strtab + symnum);
4486 verndx = VER_NDX(obj->versyms[symnum]);
4487 if (verndx > obj->vernum) {
4488 _rtld_error("%s: symbol %s references wrong version %d",
4489 obj->path, obj->strtab + symnum, verndx);
4492 if (obj->vertab[verndx].hash != req->ventry->hash ||
4493 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4495 * Version does not match. Look if this is a
4496 * global symbol and if it is not hidden. If
4497 * global symbol (verndx < 2) is available,
4498 * use it. Do not return symbol if we are
4499 * called by dlvsym, because dlvsym looks for
4500 * a specific version and default one is not
4501 * what dlvsym wants.
4503 if ((req->flags & SYMLOOK_DLSYM) ||
4504 (verndx >= VER_NDX_GIVEN) ||
4505 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4509 result->sym_out = symp;
4514 * Search for symbol using SysV hash function.
4515 * obj->buckets is known not to be NULL at this point; the test for this was
4516 * performed with the obj->valid_hash_sysv assignment.
4519 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4521 unsigned long symnum;
4522 Sym_Match_Result matchres;
4524 matchres.sym_out = NULL;
4525 matchres.vsymp = NULL;
4526 matchres.vcount = 0;
4528 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4529 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4530 if (symnum >= obj->nchains)
4531 return (ESRCH); /* Bad object */
4533 if (matched_symbol(req, obj, &matchres, symnum)) {
4534 req->sym_out = matchres.sym_out;
4535 req->defobj_out = obj;
4539 if (matchres.vcount == 1) {
4540 req->sym_out = matchres.vsymp;
4541 req->defobj_out = obj;
4547 /* Search for symbol using GNU hash function */
4549 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4551 Elf_Addr bloom_word;
4552 const Elf32_Word *hashval;
4554 Sym_Match_Result matchres;
4555 unsigned int h1, h2;
4556 unsigned long symnum;
4558 matchres.sym_out = NULL;
4559 matchres.vsymp = NULL;
4560 matchres.vcount = 0;
4562 /* Pick right bitmask word from Bloom filter array */
4563 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4564 obj->maskwords_bm_gnu];
4566 /* Calculate modulus word size of gnu hash and its derivative */
4567 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4568 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4570 /* Filter out the "definitely not in set" queries */
4571 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4574 /* Locate hash chain and corresponding value element*/
4575 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4578 hashval = &obj->chain_zero_gnu[bucket];
4580 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4581 symnum = hashval - obj->chain_zero_gnu;
4582 if (matched_symbol(req, obj, &matchres, symnum)) {
4583 req->sym_out = matchres.sym_out;
4584 req->defobj_out = obj;
4588 } while ((*hashval++ & 1) == 0);
4589 if (matchres.vcount == 1) {
4590 req->sym_out = matchres.vsymp;
4591 req->defobj_out = obj;
4598 trace_loaded_objects(Obj_Entry *obj)
4600 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4603 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL)
4606 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL)
4607 fmt1 = "\t%o => %p (%x)\n";
4609 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL)
4610 fmt2 = "\t%o (%x)\n";
4612 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL"));
4614 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4615 Needed_Entry *needed;
4616 const char *name, *path;
4621 if (list_containers && obj->needed != NULL)
4622 rtld_printf("%s:\n", obj->path);
4623 for (needed = obj->needed; needed; needed = needed->next) {
4624 if (needed->obj != NULL) {
4625 if (needed->obj->traced && !list_containers)
4627 needed->obj->traced = true;
4628 path = needed->obj->path;
4632 name = obj->strtab + needed->name;
4633 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4635 fmt = is_lib ? fmt1 : fmt2;
4636 while ((c = *fmt++) != '\0') {
4662 rtld_putstr(main_local);
4665 rtld_putstr(obj_main->path);
4672 rtld_printf("%d", sodp->sod_major);
4675 rtld_printf("%d", sodp->sod_minor);
4682 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4695 * Unload a dlopened object and its dependencies from memory and from
4696 * our data structures. It is assumed that the DAG rooted in the
4697 * object has already been unreferenced, and that the object has a
4698 * reference count of 0.
4701 unload_object(Obj_Entry *root, RtldLockState *lockstate)
4703 Obj_Entry marker, *obj, *next;
4705 assert(root->refcount == 0);
4708 * Pass over the DAG removing unreferenced objects from
4709 * appropriate lists.
4711 unlink_object(root);
4713 /* Unmap all objects that are no longer referenced. */
4714 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
4715 next = TAILQ_NEXT(obj, next);
4716 if (obj->marker || obj->refcount != 0)
4718 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
4719 obj->mapsize, 0, obj->path);
4720 dbg("unloading \"%s\"", obj->path);
4722 * Unlink the object now to prevent new references from
4723 * being acquired while the bind lock is dropped in
4724 * recursive dlclose() invocations.
4726 TAILQ_REMOVE(&obj_list, obj, next);
4729 if (obj->filtees_loaded) {
4731 init_marker(&marker);
4732 TAILQ_INSERT_BEFORE(next, &marker, next);
4733 unload_filtees(obj, lockstate);
4734 next = TAILQ_NEXT(&marker, next);
4735 TAILQ_REMOVE(&obj_list, &marker, next);
4737 unload_filtees(obj, lockstate);
4739 release_object(obj);
4744 unlink_object(Obj_Entry *root)
4748 if (root->refcount == 0) {
4749 /* Remove the object from the RTLD_GLOBAL list. */
4750 objlist_remove(&list_global, root);
4752 /* Remove the object from all objects' DAG lists. */
4753 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4754 objlist_remove(&elm->obj->dldags, root);
4755 if (elm->obj != root)
4756 unlink_object(elm->obj);
4762 ref_dag(Obj_Entry *root)
4766 assert(root->dag_inited);
4767 STAILQ_FOREACH(elm, &root->dagmembers, link)
4768 elm->obj->refcount++;
4772 unref_dag(Obj_Entry *root)
4776 assert(root->dag_inited);
4777 STAILQ_FOREACH(elm, &root->dagmembers, link)
4778 elm->obj->refcount--;
4782 * Common code for MD __tls_get_addr().
4784 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4786 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4788 Elf_Addr *newdtv, *dtv;
4789 RtldLockState lockstate;
4793 /* Check dtv generation in case new modules have arrived */
4794 if (dtv[0] != tls_dtv_generation) {
4795 wlock_acquire(rtld_bind_lock, &lockstate);
4796 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4798 if (to_copy > tls_max_index)
4799 to_copy = tls_max_index;
4800 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4801 newdtv[0] = tls_dtv_generation;
4802 newdtv[1] = tls_max_index;
4804 lock_release(rtld_bind_lock, &lockstate);
4805 dtv = *dtvp = newdtv;
4808 /* Dynamically allocate module TLS if necessary */
4809 if (dtv[index + 1] == 0) {
4810 /* Signal safe, wlock will block out signals. */
4811 wlock_acquire(rtld_bind_lock, &lockstate);
4812 if (!dtv[index + 1])
4813 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4814 lock_release(rtld_bind_lock, &lockstate);
4816 return ((void *)(dtv[index + 1] + offset));
4820 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4825 /* Check dtv generation in case new modules have arrived */
4826 if (__predict_true(dtv[0] == tls_dtv_generation &&
4827 dtv[index + 1] != 0))
4828 return ((void *)(dtv[index + 1] + offset));
4829 return (tls_get_addr_slow(dtvp, index, offset));
4832 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
4833 defined(__powerpc__) || defined(__riscv)
4836 * Return pointer to allocated TLS block
4839 get_tls_block_ptr(void *tcb, size_t tcbsize)
4841 size_t extra_size, post_size, pre_size, tls_block_size;
4842 size_t tls_init_align;
4844 tls_init_align = MAX(obj_main->tlsalign, 1);
4846 /* Compute fragments sizes. */
4847 extra_size = tcbsize - TLS_TCB_SIZE;
4848 post_size = calculate_tls_post_size(tls_init_align);
4849 tls_block_size = tcbsize + post_size;
4850 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4852 return ((char *)tcb - pre_size - extra_size);
4856 * Allocate Static TLS using the Variant I method.
4858 * For details on the layout, see lib/libc/gen/tls.c.
4860 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as
4861 * it is based on tls_last_offset, and TLS offsets here are really TCB
4862 * offsets, whereas libc's tls_static_space is just the executable's static
4866 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4870 Elf_Addr *dtv, **tcb;
4873 size_t extra_size, maxalign, post_size, pre_size, tls_block_size;
4874 size_t tls_init_align, tls_init_offset;
4876 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4879 assert(tcbsize >= TLS_TCB_SIZE);
4880 maxalign = MAX(tcbalign, tls_static_max_align);
4881 tls_init_align = MAX(obj_main->tlsalign, 1);
4883 /* Compute fragmets sizes. */
4884 extra_size = tcbsize - TLS_TCB_SIZE;
4885 post_size = calculate_tls_post_size(tls_init_align);
4886 tls_block_size = tcbsize + post_size;
4887 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4888 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size;
4890 /* Allocate whole TLS block */
4891 tls_block = malloc_aligned(tls_block_size, maxalign, 0);
4892 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size);
4894 if (oldtcb != NULL) {
4895 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize),
4897 free_aligned(get_tls_block_ptr(oldtcb, tcbsize));
4899 /* Adjust the DTV. */
4901 for (i = 0; i < dtv[1]; i++) {
4902 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4903 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4904 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb;
4908 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4910 dtv[0] = tls_dtv_generation;
4911 dtv[1] = tls_max_index;
4913 for (obj = globallist_curr(objs); obj != NULL;
4914 obj = globallist_next(obj)) {
4915 if (obj->tlsoffset == 0)
4917 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1);
4918 addr = (Elf_Addr)tcb + obj->tlsoffset;
4919 if (tls_init_offset > 0)
4920 memset((void *)addr, 0, tls_init_offset);
4921 if (obj->tlsinitsize > 0) {
4922 memcpy((void *)(addr + tls_init_offset), obj->tlsinit,
4925 if (obj->tlssize > obj->tlsinitsize) {
4926 memset((void *)(addr + tls_init_offset + obj->tlsinitsize),
4927 0, obj->tlssize - obj->tlsinitsize - tls_init_offset);
4929 dtv[obj->tlsindex + 1] = addr;
4937 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
4940 Elf_Addr tlsstart, tlsend;
4942 size_t dtvsize, i, tls_init_align;
4944 assert(tcbsize >= TLS_TCB_SIZE);
4945 tls_init_align = MAX(obj_main->tlsalign, 1);
4947 /* Compute fragments sizes. */
4948 post_size = calculate_tls_post_size(tls_init_align);
4950 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size;
4951 tlsend = (Elf_Addr)tcb + tls_static_space;
4953 dtv = *(Elf_Addr **)tcb;
4955 for (i = 0; i < dtvsize; i++) {
4956 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4957 free((void*)dtv[i+2]);
4961 free_aligned(get_tls_block_ptr(tcb, tcbsize));
4966 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4969 * Allocate Static TLS using the Variant II method.
4972 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4975 size_t size, ralign;
4977 Elf_Addr *dtv, *olddtv;
4978 Elf_Addr segbase, oldsegbase, addr;
4982 if (tls_static_max_align > ralign)
4983 ralign = tls_static_max_align;
4984 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign);
4986 assert(tcbsize >= 2*sizeof(Elf_Addr));
4987 tls = malloc_aligned(size, ralign, 0 /* XXX */);
4988 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4990 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign));
4991 ((Elf_Addr*)segbase)[0] = segbase;
4992 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4994 dtv[0] = tls_dtv_generation;
4995 dtv[1] = tls_max_index;
4999 * Copy the static TLS block over whole.
5001 oldsegbase = (Elf_Addr) oldtls;
5002 memcpy((void *)(segbase - tls_static_space),
5003 (const void *)(oldsegbase - tls_static_space),
5007 * If any dynamic TLS blocks have been created tls_get_addr(),
5010 olddtv = ((Elf_Addr**)oldsegbase)[1];
5011 for (i = 0; i < olddtv[1]; i++) {
5012 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
5013 dtv[i+2] = olddtv[i+2];
5019 * We assume that this block was the one we created with
5020 * allocate_initial_tls().
5022 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
5024 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
5025 if (obj->marker || obj->tlsoffset == 0)
5027 addr = segbase - obj->tlsoffset;
5028 memset((void*)(addr + obj->tlsinitsize),
5029 0, obj->tlssize - obj->tlsinitsize);
5031 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
5032 obj->static_tls_copied = true;
5034 dtv[obj->tlsindex + 1] = addr;
5038 return (void*) segbase;
5042 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign)
5045 size_t size, ralign;
5047 Elf_Addr tlsstart, tlsend;
5050 * Figure out the size of the initial TLS block so that we can
5051 * find stuff which ___tls_get_addr() allocated dynamically.
5054 if (tls_static_max_align > ralign)
5055 ralign = tls_static_max_align;
5056 size = roundup(tls_static_space, ralign);
5058 dtv = ((Elf_Addr**)tls)[1];
5060 tlsend = (Elf_Addr) tls;
5061 tlsstart = tlsend - size;
5062 for (i = 0; i < dtvsize; i++) {
5063 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
5064 free_aligned((void *)dtv[i + 2]);
5068 free_aligned((void *)tlsstart);
5075 * Allocate TLS block for module with given index.
5078 allocate_module_tls(int index)
5083 TAILQ_FOREACH(obj, &obj_list, next) {
5086 if (obj->tlsindex == index)
5090 _rtld_error("Can't find module with TLS index %d", index);
5094 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset);
5095 memcpy(p, obj->tlsinit, obj->tlsinitsize);
5096 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
5101 allocate_tls_offset(Obj_Entry *obj)
5108 if (obj->tlssize == 0) {
5109 obj->tls_done = true;
5113 if (tls_last_offset == 0)
5114 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign,
5117 off = calculate_tls_offset(tls_last_offset, tls_last_size,
5118 obj->tlssize, obj->tlsalign, obj->tlspoffset);
5121 * If we have already fixed the size of the static TLS block, we
5122 * must stay within that size. When allocating the static TLS, we
5123 * leave a small amount of space spare to be used for dynamically
5124 * loading modules which use static TLS.
5126 if (tls_static_space != 0) {
5127 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
5129 } else if (obj->tlsalign > tls_static_max_align) {
5130 tls_static_max_align = obj->tlsalign;
5133 tls_last_offset = obj->tlsoffset = off;
5134 tls_last_size = obj->tlssize;
5135 obj->tls_done = true;
5141 free_tls_offset(Obj_Entry *obj)
5145 * If we were the last thing to allocate out of the static TLS
5146 * block, we give our space back to the 'allocator'. This is a
5147 * simplistic workaround to allow libGL.so.1 to be loaded and
5148 * unloaded multiple times.
5150 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
5151 == calculate_tls_end(tls_last_offset, tls_last_size)) {
5152 tls_last_offset -= obj->tlssize;
5158 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
5161 RtldLockState lockstate;
5163 wlock_acquire(rtld_bind_lock, &lockstate);
5164 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
5166 lock_release(rtld_bind_lock, &lockstate);
5171 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
5173 RtldLockState lockstate;
5175 wlock_acquire(rtld_bind_lock, &lockstate);
5176 free_tls(tcb, tcbsize, tcbalign);
5177 lock_release(rtld_bind_lock, &lockstate);
5181 object_add_name(Obj_Entry *obj, const char *name)
5187 entry = malloc(sizeof(Name_Entry) + len);
5189 if (entry != NULL) {
5190 strcpy(entry->name, name);
5191 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5196 object_match_name(const Obj_Entry *obj, const char *name)
5200 STAILQ_FOREACH(entry, &obj->names, link) {
5201 if (strcmp(name, entry->name) == 0)
5208 locate_dependency(const Obj_Entry *obj, const char *name)
5210 const Objlist_Entry *entry;
5211 const Needed_Entry *needed;
5213 STAILQ_FOREACH(entry, &list_main, link) {
5214 if (object_match_name(entry->obj, name))
5218 for (needed = obj->needed; needed != NULL; needed = needed->next) {
5219 if (strcmp(obj->strtab + needed->name, name) == 0 ||
5220 (needed->obj != NULL && object_match_name(needed->obj, name))) {
5222 * If there is DT_NEEDED for the name we are looking for,
5223 * we are all set. Note that object might not be found if
5224 * dependency was not loaded yet, so the function can
5225 * return NULL here. This is expected and handled
5226 * properly by the caller.
5228 return (needed->obj);
5231 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
5237 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
5238 const Elf_Vernaux *vna)
5240 const Elf_Verdef *vd;
5241 const char *vername;
5243 vername = refobj->strtab + vna->vna_name;
5244 vd = depobj->verdef;
5246 _rtld_error("%s: version %s required by %s not defined",
5247 depobj->path, vername, refobj->path);
5251 if (vd->vd_version != VER_DEF_CURRENT) {
5252 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5253 depobj->path, vd->vd_version);
5256 if (vna->vna_hash == vd->vd_hash) {
5257 const Elf_Verdaux *aux = (const Elf_Verdaux *)
5258 ((const char *)vd + vd->vd_aux);
5259 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
5262 if (vd->vd_next == 0)
5264 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5266 if (vna->vna_flags & VER_FLG_WEAK)
5268 _rtld_error("%s: version %s required by %s not found",
5269 depobj->path, vername, refobj->path);
5274 rtld_verify_object_versions(Obj_Entry *obj)
5276 const Elf_Verneed *vn;
5277 const Elf_Verdef *vd;
5278 const Elf_Verdaux *vda;
5279 const Elf_Vernaux *vna;
5280 const Obj_Entry *depobj;
5281 int maxvernum, vernum;
5283 if (obj->ver_checked)
5285 obj->ver_checked = true;
5289 * Walk over defined and required version records and figure out
5290 * max index used by any of them. Do very basic sanity checking
5294 while (vn != NULL) {
5295 if (vn->vn_version != VER_NEED_CURRENT) {
5296 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
5297 obj->path, vn->vn_version);
5300 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5302 vernum = VER_NEED_IDX(vna->vna_other);
5303 if (vernum > maxvernum)
5305 if (vna->vna_next == 0)
5307 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5309 if (vn->vn_next == 0)
5311 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5315 while (vd != NULL) {
5316 if (vd->vd_version != VER_DEF_CURRENT) {
5317 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5318 obj->path, vd->vd_version);
5321 vernum = VER_DEF_IDX(vd->vd_ndx);
5322 if (vernum > maxvernum)
5324 if (vd->vd_next == 0)
5326 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5333 * Store version information in array indexable by version index.
5334 * Verify that object version requirements are satisfied along the
5337 obj->vernum = maxvernum + 1;
5338 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
5341 while (vd != NULL) {
5342 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
5343 vernum = VER_DEF_IDX(vd->vd_ndx);
5344 assert(vernum <= maxvernum);
5345 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux);
5346 obj->vertab[vernum].hash = vd->vd_hash;
5347 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
5348 obj->vertab[vernum].file = NULL;
5349 obj->vertab[vernum].flags = 0;
5351 if (vd->vd_next == 0)
5353 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5357 while (vn != NULL) {
5358 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
5361 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5363 if (check_object_provided_version(obj, depobj, vna))
5365 vernum = VER_NEED_IDX(vna->vna_other);
5366 assert(vernum <= maxvernum);
5367 obj->vertab[vernum].hash = vna->vna_hash;
5368 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
5369 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
5370 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
5371 VER_INFO_HIDDEN : 0;
5372 if (vna->vna_next == 0)
5374 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5376 if (vn->vn_next == 0)
5378 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5384 rtld_verify_versions(const Objlist *objlist)
5386 Objlist_Entry *entry;
5390 STAILQ_FOREACH(entry, objlist, link) {
5392 * Skip dummy objects or objects that have their version requirements
5395 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
5397 if (rtld_verify_object_versions(entry->obj) == -1) {
5399 if (ld_tracing == NULL)
5403 if (rc == 0 || ld_tracing != NULL)
5404 rc = rtld_verify_object_versions(&obj_rtld);
5409 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
5414 vernum = VER_NDX(obj->versyms[symnum]);
5415 if (vernum >= obj->vernum) {
5416 _rtld_error("%s: symbol %s has wrong verneed value %d",
5417 obj->path, obj->strtab + symnum, vernum);
5418 } else if (obj->vertab[vernum].hash != 0) {
5419 return &obj->vertab[vernum];
5426 _rtld_get_stack_prot(void)
5429 return (stack_prot);
5433 _rtld_is_dlopened(void *arg)
5436 RtldLockState lockstate;
5439 rlock_acquire(rtld_bind_lock, &lockstate);
5442 obj = obj_from_addr(arg);
5444 _rtld_error("No shared object contains address");
5445 lock_release(rtld_bind_lock, &lockstate);
5448 res = obj->dlopened ? 1 : 0;
5449 lock_release(rtld_bind_lock, &lockstate);
5454 obj_remap_relro(Obj_Entry *obj, int prot)
5457 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size,
5459 _rtld_error("%s: Cannot set relro protection to %#x: %s",
5460 obj->path, prot, rtld_strerror(errno));
5467 obj_disable_relro(Obj_Entry *obj)
5470 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE));
5474 obj_enforce_relro(Obj_Entry *obj)
5477 return (obj_remap_relro(obj, PROT_READ));
5481 map_stacks_exec(RtldLockState *lockstate)
5483 void (*thr_map_stacks_exec)(void);
5485 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
5487 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
5488 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
5489 if (thr_map_stacks_exec != NULL) {
5490 stack_prot |= PROT_EXEC;
5491 thr_map_stacks_exec();
5496 distribute_static_tls(Objlist *list, RtldLockState *lockstate)
5500 void (*distrib)(size_t, void *, size_t, size_t);
5502 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t)
5503 get_program_var_addr("__pthread_distribute_static_tls", lockstate);
5504 if (distrib == NULL)
5506 STAILQ_FOREACH(elm, list, link) {
5508 if (obj->marker || !obj->tls_done || obj->static_tls_copied)
5510 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize,
5512 obj->static_tls_copied = true;
5517 symlook_init(SymLook *dst, const char *name)
5520 bzero(dst, sizeof(*dst));
5522 dst->hash = elf_hash(name);
5523 dst->hash_gnu = gnu_hash(name);
5527 symlook_init_from_req(SymLook *dst, const SymLook *src)
5530 dst->name = src->name;
5531 dst->hash = src->hash;
5532 dst->hash_gnu = src->hash_gnu;
5533 dst->ventry = src->ventry;
5534 dst->flags = src->flags;
5535 dst->defobj_out = NULL;
5536 dst->sym_out = NULL;
5537 dst->lockstate = src->lockstate;
5541 open_binary_fd(const char *argv0, bool search_in_path,
5542 const char **binpath_res)
5544 char *binpath, *pathenv, *pe, *res1;
5550 if (search_in_path && strchr(argv0, '/') == NULL) {
5551 binpath = xmalloc(PATH_MAX);
5552 pathenv = getenv("PATH");
5553 if (pathenv == NULL) {
5554 _rtld_error("-p and no PATH environment variable");
5557 pathenv = strdup(pathenv);
5558 if (pathenv == NULL) {
5559 _rtld_error("Cannot allocate memory");
5564 while ((pe = strsep(&pathenv, ":")) != NULL) {
5565 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX)
5567 if (binpath[0] != '\0' &&
5568 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX)
5570 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX)
5572 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
5573 if (fd != -1 || errno != ENOENT) {
5580 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
5585 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno));
5588 if (res != NULL && res[0] != '/') {
5589 res1 = xmalloc(PATH_MAX);
5590 if (realpath(res, res1) != NULL) {
5592 free(__DECONST(char *, res));
5603 * Parse a set of command-line arguments.
5606 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp,
5612 int arglen, fd, i, j, mib[2];
5614 bool seen_b, seen_f;
5616 dbg("Parsing command-line arguments");
5619 seen_b = seen_f = false;
5621 for (i = 1; i < argc; i++ ) {
5623 dbg("argv[%d]: '%s'", i, arg);
5626 * rtld arguments end with an explicit "--" or with the first
5627 * non-prefixed argument.
5629 if (strcmp(arg, "--") == 0) {
5637 * All other arguments are single-character options that can
5638 * be combined, so we need to search through `arg` for them.
5640 arglen = strlen(arg);
5641 for (j = 1; j < arglen; j++) {
5644 print_usage(argv[0]);
5646 } else if (opt == 'b') {
5648 _rtld_error("Both -b and -f specified");
5655 } else if (opt == 'f') {
5657 _rtld_error("Both -b and -f specified");
5662 * -f XX can be used to specify a
5663 * descriptor for the binary named at
5664 * the command line (i.e., the later
5665 * argument will specify the process
5666 * name but the descriptor is what
5667 * will actually be executed).
5669 * -f must be the last option in, e.g., -abcf.
5671 if (j != arglen - 1) {
5672 _rtld_error("Invalid options: %s", arg);
5676 fd = parse_integer(argv[i]);
5679 "Invalid file descriptor: '%s'",
5686 } else if (opt == 'p') {
5688 } else if (opt == 'v') {
5691 mib[1] = HW_MACHINE;
5692 sz = sizeof(machine);
5693 sysctl(mib, nitems(mib), machine, &sz, NULL, 0);
5695 "FreeBSD ld-elf.so.1 %s\n"
5696 "FreeBSD_version %d\n"
5697 "Default lib path %s\n"
5702 __FreeBSD_version, ld_standard_library_path,
5703 ld_env_prefix, ld_elf_hints_default,
5704 ld_path_libmap_conf);
5707 _rtld_error("Invalid argument: '%s'", arg);
5708 print_usage(argv[0]);
5720 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
5723 parse_integer(const char *str)
5725 static const int RADIX = 10; /* XXXJA: possibly support hex? */
5732 for (c = *str; c != '\0'; c = *++str) {
5733 if (c < '0' || c > '9')
5740 /* Make sure we actually parsed something. */
5747 print_usage(const char *argv0)
5751 "Usage: %s [-h] [-b <exe>] [-f <FD>] [-p] [--] <binary> [<args>]\n"
5754 " -h Display this help message\n"
5755 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n"
5756 " -f <FD> Execute <FD> instead of searching for <binary>\n"
5757 " -p Search in PATH for named binary\n"
5758 " -v Display identification information\n"
5759 " -- End of RTLD options\n"
5760 " <binary> Name of process to execute\n"
5761 " <args> Arguments to the executed process\n", argv0);
5765 * Overrides for libc_pic-provided functions.
5769 __getosreldate(void)
5779 oid[1] = KERN_OSRELDATE;
5781 len = sizeof(osrel);
5782 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5783 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5795 void (*__cleanup)(void);
5796 int __isthreaded = 0;
5797 int _thread_autoinit_dummy_decl = 1;
5800 * No unresolved symbols for rtld.
5803 __pthread_cxa_finalize(struct dl_phdr_info *a __unused)
5808 rtld_strerror(int errnum)
5811 if (errnum < 0 || errnum >= sys_nerr)
5812 return ("Unknown error");
5813 return (sys_errlist[errnum]);
5817 * No ifunc relocations.
5820 memset(void *dest, int c, size_t len)
5824 for (i = 0; i < len; i++)
5825 ((char *)dest)[i] = c;
5830 bzero(void *dest, size_t len)
5834 for (i = 0; i < len; i++)
5835 ((char *)dest)[i] = 0;
5840 malloc(size_t nbytes)
5843 return (__crt_malloc(nbytes));
5847 calloc(size_t num, size_t size)
5850 return (__crt_calloc(num, size));
5861 realloc(void *cp, size_t nbytes)
5864 return (__crt_realloc(cp, nbytes));
5867 extern int _rtld_version__FreeBSD_version __exported;
5868 int _rtld_version__FreeBSD_version = __FreeBSD_version;
5870 extern char _rtld_version_laddr_offset __exported;
5871 char _rtld_version_laddr_offset;