rtld: Add stubs to support PT_GNU_STACK
[dragonfly.git] / libexec / rtld-elf / rtld.c
CommitLineData
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1/*-
2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
fcf53d9b 4 * Copyright 2009, 2010, 2011 Konstantin Belousov <kib@FreeBSD.ORG>.
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5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 *
f4f4bfd5 27 * $FreeBSD$
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28 */
29
30/*
31 * Dynamic linker for ELF.
32 *
33 * John Polstra <jdp@polstra.com>.
34 */
35
36#ifndef __GNUC__
37#error "GCC is needed to compile this file"
38#endif
39
40#include <sys/param.h>
fcf53d9b 41#include <sys/mount.h>
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42#include <sys/mman.h>
43#include <sys/stat.h>
b566341b 44#include <sys/sysctl.h>
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45#include <sys/uio.h>
46#include <sys/utsname.h>
47#include <sys/ktrace.h>
8ca15ec8 48#include <sys/resident.h>
bc633d63 49#include <sys/tls.h>
984263bc 50
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51#include <machine/tls.h>
52
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53#include <dlfcn.h>
54#include <err.h>
55#include <errno.h>
56#include <fcntl.h>
57#include <stdarg.h>
58#include <stdio.h>
59#include <stdlib.h>
60#include <string.h>
61#include <unistd.h>
62
63#include "debug.h"
64#include "rtld.h"
fcf53d9b 65#include "libmap.h"
abfcd5b1 66#include "rtld_printf.h"
984263bc 67
a1eee96a 68#define PATH_RTLD "/usr/libexec/ld-elf.so.2"
8ca15ec8 69#define LD_ARY_CACHE 16
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70
71/* Types. */
72typedef void (*func_ptr_type)();
73typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
74
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75/*
76 * Function declarations.
77 */
8ca15ec8 78static const char *_getenv_ld(const char *id);
fcf53d9b 79static void die(void) __dead2;
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80static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
81 const Elf_Dyn **);
82static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *);
fcf53d9b 83static void digest_dynamic(Obj_Entry *, int);
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84static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
85static Obj_Entry *dlcheck(void *);
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86static Obj_Entry *dlopen_object(const char *name, Obj_Entry *refobj,
87 int lo_flags, int mode);
fcf53d9b 88static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
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89static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
90static bool donelist_check(DoneList *, const Obj_Entry *);
91static void errmsg_restore(char *);
92static char *errmsg_save(void);
93static void *fill_search_info(const char *, size_t, void *);
94static char *find_library(const char *, const Obj_Entry *);
95static const char *gethints(void);
96static void init_dag(Obj_Entry *);
fcf53d9b 97static void init_dag1(Obj_Entry *, Obj_Entry *, DoneList *);
b566341b 98static void init_rtld(caddr_t, Elf_Auxinfo **);
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99static void initlist_add_neededs(Needed_Entry *, Objlist *);
100static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
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101static bool is_exported(const Elf_Sym *);
102static void linkmap_add(Obj_Entry *);
103static void linkmap_delete(Obj_Entry *);
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104static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
105static void unload_filtees(Obj_Entry *);
fcf53d9b 106static int load_needed_objects(Obj_Entry *, int);
984263bc 107static int load_preload_objects(void);
fcf53d9b 108static Obj_Entry *load_object(const char *, const Obj_Entry *, int);
e9de6dcc 109static void map_stacks_exec(RtldLockState *);
984263bc 110static Obj_Entry *obj_from_addr(const void *);
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111static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
112static void objlist_call_init(Objlist *, RtldLockState *);
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113static void objlist_clear(Objlist *);
114static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
115static void objlist_init(Objlist *);
116static void objlist_push_head(Objlist *, Obj_Entry *);
117static void objlist_push_tail(Objlist *, Obj_Entry *);
118static void objlist_remove(Objlist *, Obj_Entry *);
984263bc 119static void *path_enumerate(const char *, path_enum_proc, void *);
35b2b265 120static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, RtldLockState *);
984263bc 121static int rtld_dirname(const char *, char *);
fcf53d9b 122static int rtld_dirname_abs(const char *, char *);
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123static void rtld_exit(void);
124static char *search_library_path(const char *, const char *);
fcf53d9b 125static const void **get_program_var_addr(const char *);
984263bc 126static void set_program_var(const char *, const void *);
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127static int symlook_default(SymLook *, const Obj_Entry *refobj);
128static void symlook_init_from_req(SymLook *, const SymLook *);
129static int symlook_list(SymLook *, const Objlist *, DoneList *);
130static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
131static int symlook_obj1(SymLook *, const Obj_Entry *);
fcf53d9b 132static void trace_loaded_objects(Obj_Entry *);
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133static void unlink_object(Obj_Entry *);
134static void unload_object(Obj_Entry *);
135static void unref_dag(Obj_Entry *);
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136static void ref_dag(Obj_Entry *);
137static int origin_subst_one(char **, const char *, const char *,
138 const char *, char *);
139static char *origin_subst(const char *, const char *);
140static int rtld_verify_versions(const Objlist *);
141static int rtld_verify_object_versions(Obj_Entry *);
142static void object_add_name(Obj_Entry *, const char *);
143static int object_match_name(const Obj_Entry *, const char *);
144static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
145static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
146 struct dl_phdr_info *phdr_info);
147
8301820e 148void r_debug_state(struct r_debug *, struct link_map *) __noinline;
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149
150/*
151 * Data declarations.
152 */
153static char *error_message; /* Message for dlerror(), or NULL */
154struct r_debug r_debug; /* for GDB; */
fcf53d9b 155static bool libmap_disable; /* Disable libmap */
35b2b265 156static bool ld_loadfltr; /* Immediate filters processing */
fcf53d9b 157static char *libmap_override; /* Maps to use in addition to libmap.conf */
984263bc 158static bool trust; /* False for setuid and setgid programs */
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159static bool dangerous_ld_env; /* True if environment variables have been
160 used to affect the libraries loaded */
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161static const char *ld_bind_now; /* Environment variable for immediate binding */
162static const char *ld_debug; /* Environment variable for debugging */
163static const char *ld_library_path; /* Environment variable for search path */
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164static char *ld_preload; /* Environment variable for libraries to
165 load first */
fcf53d9b 166static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */
b566341b 167static const char *ld_tracing; /* Called from ldd to print libs */
fcf53d9b 168static const char *ld_utrace; /* Use utrace() to log events. */
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169static int (*rtld_functrace)( /* Optional function call tracing hook */
170 const char *caller_obj,
171 const char *callee_obj,
172 const char *callee_func,
173 void *stack);
35b2b265 174static const Obj_Entry *rtld_functrace_obj; /* Object thereof */
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175static Obj_Entry *obj_list; /* Head of linked list of shared objects */
176static Obj_Entry **obj_tail; /* Link field of last object in list */
8ca15ec8 177static Obj_Entry **preload_tail;
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178static Obj_Entry *obj_main; /* The main program shared object */
179static Obj_Entry obj_rtld; /* The dynamic linker shared object */
180static unsigned int obj_count; /* Number of objects in obj_list */
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181static unsigned int obj_loads; /* Number of objects in obj_list */
182
33a8b578 183static int ld_resident; /* Non-zero if resident */
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184static const char *ld_ary[LD_ARY_CACHE];
185static int ld_index;
a1eee96a 186static Objlist initlist;
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187
188static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
189 STAILQ_HEAD_INITIALIZER(list_global);
190static Objlist list_main = /* Objects loaded at program startup */
191 STAILQ_HEAD_INITIALIZER(list_main);
192static Objlist list_fini = /* Objects needing fini() calls */
193 STAILQ_HEAD_INITIALIZER(list_fini);
194
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195static Elf_Sym sym_zero; /* For resolving undefined weak refs. */
196
197#define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
198
199extern Elf_Dyn _DYNAMIC;
200#pragma weak _DYNAMIC
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201#ifndef RTLD_IS_DYNAMIC
202#define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
203#endif
984263bc 204
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205#ifdef ENABLE_OSRELDATE
206int osreldate;
207#endif
208
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209static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
210static int max_stack_flags;
211
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212/*
213 * These are the functions the dynamic linker exports to application
214 * programs. They are the only symbols the dynamic linker is willing
215 * to export from itself.
216 */
217static func_ptr_type exports[] = {
218 (func_ptr_type) &_rtld_error,
219 (func_ptr_type) &dlclose,
220 (func_ptr_type) &dlerror,
221 (func_ptr_type) &dlopen,
fcf53d9b 222 (func_ptr_type) &dlfunc,
984263bc 223 (func_ptr_type) &dlsym,
fcf53d9b 224 (func_ptr_type) &dlvsym,
984263bc 225 (func_ptr_type) &dladdr,
984263bc 226 (func_ptr_type) &dlinfo,
fcf53d9b 227 (func_ptr_type) &dl_iterate_phdr,
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228#ifdef __i386__
229 (func_ptr_type) &___tls_get_addr,
230#endif
231 (func_ptr_type) &__tls_get_addr,
a1eee96a 232 (func_ptr_type) &__tls_get_addr_tcb,
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233 (func_ptr_type) &_rtld_allocate_tls,
234 (func_ptr_type) &_rtld_free_tls,
a1eee96a 235 (func_ptr_type) &_rtld_call_init,
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236 (func_ptr_type) &_rtld_thread_init,
237 (func_ptr_type) &_rtld_addr_phdr,
e9de6dcc 238 (func_ptr_type) &_rtld_get_stack_prot,
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239 NULL
240};
241
242/*
243 * Global declarations normally provided by crt1. The dynamic linker is
244 * not built with crt1, so we have to provide them ourselves.
245 */
246char *__progname;
247char **environ;
248
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249/*
250 * Globals to control TLS allocation.
251 */
252size_t tls_last_offset; /* Static TLS offset of last module */
253size_t tls_last_size; /* Static TLS size of last module */
254size_t tls_static_space; /* Static TLS space allocated */
255int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
256int tls_max_index = 1; /* Largest module index allocated */
257
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258/*
259 * Fill in a DoneList with an allocation large enough to hold all of
260 * the currently-loaded objects. Keep this as a macro since it calls
261 * alloca and we want that to occur within the scope of the caller.
262 */
263#define donelist_init(dlp) \
264 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
265 assert((dlp)->objs != NULL), \
266 (dlp)->num_alloc = obj_count, \
267 (dlp)->num_used = 0)
268
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269#define UTRACE_DLOPEN_START 1
270#define UTRACE_DLOPEN_STOP 2
271#define UTRACE_DLCLOSE_START 3
272#define UTRACE_DLCLOSE_STOP 4
273#define UTRACE_LOAD_OBJECT 5
274#define UTRACE_UNLOAD_OBJECT 6
275#define UTRACE_ADD_RUNDEP 7
276#define UTRACE_PRELOAD_FINISHED 8
277#define UTRACE_INIT_CALL 9
278#define UTRACE_FINI_CALL 10
279
280struct utrace_rtld {
281 char sig[4]; /* 'RTLD' */
282 int event;
283 void *handle;
284 void *mapbase; /* Used for 'parent' and 'init/fini' */
285 size_t mapsize;
286 int refcnt; /* Used for 'mode' */
287 char name[MAXPATHLEN];
288};
984263bc 289
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290#define LD_UTRACE(e, h, mb, ms, r, n) do { \
291 if (ld_utrace != NULL) \
292 ld_utrace_log(e, h, mb, ms, r, n); \
293} while (0)
984263bc 294
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295static void
296ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
297 int refcnt, const char *name)
298{
299 struct utrace_rtld ut;
300
301 ut.sig[0] = 'R';
302 ut.sig[1] = 'T';
303 ut.sig[2] = 'L';
304 ut.sig[3] = 'D';
305 ut.event = event;
306 ut.handle = handle;
307 ut.mapbase = mapbase;
308 ut.mapsize = mapsize;
309 ut.refcnt = refcnt;
310 bzero(ut.name, sizeof(ut.name));
311 if (name)
312 strlcpy(ut.name, name, sizeof(ut.name));
313 utrace(&ut, sizeof(ut));
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314}
315
316/*
317 * Main entry point for dynamic linking. The first argument is the
318 * stack pointer. The stack is expected to be laid out as described
319 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
320 * Specifically, the stack pointer points to a word containing
321 * ARGC. Following that in the stack is a null-terminated sequence
322 * of pointers to argument strings. Then comes a null-terminated
323 * sequence of pointers to environment strings. Finally, there is a
324 * sequence of "auxiliary vector" entries.
325 *
326 * The second argument points to a place to store the dynamic linker's
327 * exit procedure pointer and the third to a place to store the main
328 * program's object.
329 *
330 * The return value is the main program's entry point.
331 */
332func_ptr_type
333_rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
334{
335 Elf_Auxinfo *aux_info[AT_COUNT];
336 int i;
337 int argc;
338 char **argv;
339 char **env;
340 Elf_Auxinfo *aux;
341 Elf_Auxinfo *auxp;
342 const char *argv0;
55b88cae 343 Objlist_Entry *entry;
984263bc 344 Obj_Entry *obj;
984263bc 345
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346 /* marino: DO NOT MOVE THESE VARIABLES TO _rtld
347 Obj_Entry **preload_tail;
348 Objlist initlist;
35b2b265 349 from global to here. It will break the DWARF2 unwind scheme.
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350 The system compilers were unaffected, but not gcc 4.6
351 */
352
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353 /*
354 * On entry, the dynamic linker itself has not been relocated yet.
355 * Be very careful not to reference any global data until after
356 * init_rtld has returned. It is OK to reference file-scope statics
357 * and string constants, and to call static and global functions.
358 */
359
360 /* Find the auxiliary vector on the stack. */
361 argc = *sp++;
362 argv = (char **) sp;
363 sp += argc + 1; /* Skip over arguments and NULL terminator */
364 env = (char **) sp;
984263bc 365
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366 /*
367 * If we aren't already resident we have to dig out some more info.
368 * Note that auxinfo does not exist when we are resident.
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369 *
370 * I'm not sure about the ld_resident check. It seems to read zero
371 * prior to relocation, which is what we want. When running from a
372 * resident copy everything will be relocated so we are definitely
373 * good there.
33a8b578 374 */
5347affc 375 if (ld_resident == 0) {
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MD
376 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
377 ;
378 aux = (Elf_Auxinfo *) sp;
379
380 /* Digest the auxiliary vector. */
381 for (i = 0; i < AT_COUNT; i++)
382 aux_info[i] = NULL;
383 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
384 if (auxp->a_type < AT_COUNT)
385 aux_info[auxp->a_type] = auxp;
386 }
387
388 /* Initialize and relocate ourselves. */
389 assert(aux_info[AT_BASE] != NULL);
b566341b 390 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
33a8b578 391 }
984263bc 392
5347affc 393 ld_index = 0; /* don't use old env cache in case we are resident */
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394 __progname = obj_rtld.path;
395 argv0 = argv[0] != NULL ? argv[0] : "(null)";
396 environ = env;
397
fcf53d9b 398 trust = !issetugid();
984263bc 399
8ca15ec8 400 ld_bind_now = _getenv_ld("LD_BIND_NOW");
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401 /*
402 * If the process is tainted, then we un-set the dangerous environment
403 * variables. The process will be marked as tainted until setuid(2)
404 * is called. If any child process calls setuid(2) we do not want any
405 * future processes to honor the potentially un-safe variables.
406 */
407 if (!trust) {
408 if ( unsetenv("LD_DEBUG")
409 || unsetenv("LD_PRELOAD")
410 || unsetenv("LD_LIBRARY_PATH")
411 || unsetenv("LD_ELF_HINTS_PATH")
412 || unsetenv("LD_LIBMAP")
413 || unsetenv("LD_LIBMAP_DISABLE")
35b2b265 414 || unsetenv("LD_LOADFLTR")
fcf53d9b
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415 ) {
416 _rtld_error("environment corrupt; aborting");
417 die();
418 }
984263bc 419 }
fcf53d9b 420 ld_debug = _getenv_ld("LD_DEBUG");
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421 libmap_disable = _getenv_ld("LD_LIBMAP_DISABLE") != NULL;
422 libmap_override = (char *)_getenv_ld("LD_LIBMAP");
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423 ld_library_path = _getenv_ld("LD_LIBRARY_PATH");
424 ld_preload = (char *)_getenv_ld("LD_PRELOAD");
425 ld_elf_hints_path = _getenv_ld("LD_ELF_HINTS_PATH");
35b2b265 426 ld_loadfltr = _getenv_ld("LD_LOADFLTR") != NULL;
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427 dangerous_ld_env = (ld_library_path != NULL)
428 || (ld_preload != NULL)
429 || (ld_elf_hints_path != NULL)
35b2b265 430 || ld_loadfltr
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431 || (libmap_override != NULL)
432 || libmap_disable
433 ;
8ca15ec8 434 ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS");
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435 ld_utrace = _getenv_ld("LD_UTRACE");
436
437 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
438 ld_elf_hints_path = _PATH_ELF_HINTS;
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439
440 if (ld_debug != NULL && *ld_debug != '\0')
441 debug = 1;
442 dbg("%s is initialized, base address = %p", __progname,
443 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
444 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
445 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
446
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447 dbg("initializing thread locks");
448 lockdflt_init();
449
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450 /*
451 * If we are resident we can skip work that we have already done.
452 * Note that the stack is reset and there is no Elf_Auxinfo
453 * when running from a resident image, and the static globals setup
454 * between here and resident_skip will have already been setup.
455 */
8ca15ec8 456 if (ld_resident)
33a8b578 457 goto resident_skip1;
33a8b578 458
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459 /*
460 * Load the main program, or process its program header if it is
461 * already loaded.
462 */
463 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
464 int fd = aux_info[AT_EXECFD]->a_un.a_val;
465 dbg("loading main program");
466 obj_main = map_object(fd, argv0, NULL);
467 close(fd);
468 if (obj_main == NULL)
469 die();
e9de6dcc 470 max_stack_flags = obj->stack_flags;
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471 } else { /* Main program already loaded. */
472 const Elf_Phdr *phdr;
473 int phnum;
474 caddr_t entry;
475
476 dbg("processing main program's program header");
477 assert(aux_info[AT_PHDR] != NULL);
478 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
479 assert(aux_info[AT_PHNUM] != NULL);
480 phnum = aux_info[AT_PHNUM]->a_un.a_val;
481 assert(aux_info[AT_PHENT] != NULL);
482 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
483 assert(aux_info[AT_ENTRY] != NULL);
484 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
485 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
486 die();
487 }
488
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489 char buf[MAXPATHLEN];
490 if (aux_info[AT_EXECPATH] != 0) {
491 char *kexecpath;
492
493 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
494 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
495 if (kexecpath[0] == '/')
496 obj_main->path = kexecpath;
497 else if (getcwd(buf, sizeof(buf)) == NULL ||
498 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
499 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
500 obj_main->path = xstrdup(argv0);
501 else
502 obj_main->path = xstrdup(buf);
503 } else {
504 char resolved[MAXPATHLEN];
505 dbg("No AT_EXECPATH");
506 if (argv0[0] == '/') {
507 if (realpath(argv0, resolved) != NULL)
508 obj_main->path = xstrdup(resolved);
509 else
510 obj_main->path = xstrdup(argv0);
511 } else {
512 if (getcwd(buf, sizeof(buf)) != NULL
513 && strlcat(buf, "/", sizeof(buf)) < sizeof(buf)
514 && strlcat(buf, argv0, sizeof (buf)) < sizeof(buf)
515 && access(buf, R_OK) == 0
516 && realpath(buf, resolved) != NULL)
517 obj_main->path = xstrdup(resolved);
518 else
519 obj_main->path = xstrdup(argv0);
520 }
521 }
522 dbg("obj_main path %s", obj_main->path);
984263bc
MD
523 obj_main->mainprog = true;
524
e9de6dcc
JM
525 if (aux_info[AT_STACKPROT] != NULL &&
526 aux_info[AT_STACKPROT]->a_un.a_val != 0)
527 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
528
984263bc
MD
529 /*
530 * Get the actual dynamic linker pathname from the executable if
531 * possible. (It should always be possible.) That ensures that
532 * gdb will find the right dynamic linker even if a non-standard
533 * one is being used.
534 */
535 if (obj_main->interp != NULL &&
536 strcmp(obj_main->interp, obj_rtld.path) != 0) {
537 free(obj_rtld.path);
538 obj_rtld.path = xstrdup(obj_main->interp);
b7b05c9f 539 __progname = obj_rtld.path;
984263bc
MD
540 }
541
c3098c28 542 digest_dynamic(obj_main, 0);
984263bc
MD
543
544 linkmap_add(obj_main);
545 linkmap_add(&obj_rtld);
546
547 /* Link the main program into the list of objects. */
548 *obj_tail = obj_main;
549 obj_tail = &obj_main->next;
550 obj_count++;
fcf53d9b 551 obj_loads++;
984263bc 552 /* Make sure we don't call the main program's init and fini functions. */
fcf53d9b 553 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
984263bc
MD
554
555 /* Initialize a fake symbol for resolving undefined weak references. */
556 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
fcf53d9b
JM
557 sym_zero.st_shndx = SHN_UNDEF;
558 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
559
560 if (!libmap_disable)
561 libmap_disable = (bool)lm_init(libmap_override);
984263bc
MD
562
563 dbg("loading LD_PRELOAD libraries");
564 if (load_preload_objects() == -1)
565 die();
566 preload_tail = obj_tail;
567
568 dbg("loading needed objects");
fcf53d9b 569 if (load_needed_objects(obj_main, 0) == -1)
984263bc
MD
570 die();
571
572 /* Make a list of all objects loaded at startup. */
fcf53d9b 573 for (obj = obj_list; obj != NULL; obj = obj->next) {
984263bc 574 objlist_push_tail(&list_main, obj);
fcf53d9b
JM
575 obj->refcount++;
576 }
577
578 dbg("checking for required versions");
579 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
580 die();
984263bc 581
33a8b578
MD
582resident_skip1:
583
984263bc
MD
584 if (ld_tracing) { /* We're done */
585 trace_loaded_objects(obj_main);
586 exit(0);
587 }
588
33a8b578
MD
589 if (ld_resident) /* XXX clean this up! */
590 goto resident_skip2;
591
fcf53d9b 592 if (_getenv_ld("LD_DUMP_REL_PRE") != NULL) {
4a8d9350
JS
593 dump_relocations(obj_main);
594 exit (0);
595 }
596
55b88cae
DX
597 /* setup TLS for main thread */
598 dbg("initializing initial thread local storage");
599 STAILQ_FOREACH(entry, &list_main, link) {
600 /*
601 * Allocate all the initial objects out of the static TLS
602 * block even if they didn't ask for it.
603 */
604 allocate_tls_offset(entry->obj);
605 }
a1eee96a
MD
606
607 tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA;
608
609 /*
610 * Do not try to allocate the TLS here, let libc do it itself.
611 * (crt1 for the program will call _init_tls())
612 */
55b88cae 613
6192271e 614 if (relocate_objects(obj_main,
35b2b265 615 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld, NULL) == -1)
6192271e 616 die();
984263bc 617
6192271e
MD
618 dbg("doing copy relocations");
619 if (do_copy_relocations(obj_main) == -1)
620 die();
1c76efe5 621
33a8b578
MD
622resident_skip2:
623
8ca15ec8 624 if (_getenv_ld("LD_RESIDENT_UNREGISTER_NOW")) {
33a8b578
MD
625 if (exec_sys_unregister(-1) < 0) {
626 dbg("exec_sys_unregister failed %d\n", errno);
627 exit(errno);
628 }
629 dbg("exec_sys_unregister success\n");
630 exit(0);
631 }
984263bc 632
fcf53d9b 633 if (_getenv_ld("LD_DUMP_REL_POST") != NULL) {
4a8d9350
JS
634 dump_relocations(obj_main);
635 exit (0);
636 }
637
984263bc
MD
638 dbg("initializing key program variables");
639 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
640 set_program_var("environ", env);
b566341b 641 set_program_var("__elf_aux_vector", aux);
984263bc 642
8ca15ec8
MD
643 if (_getenv_ld("LD_RESIDENT_REGISTER_NOW")) {
644 extern void resident_start(void);
645 ld_resident = 1;
646 if (exec_sys_register(resident_start) < 0) {
647 dbg("exec_sys_register failed %d\n", errno);
648 exit(errno);
649 }
650 dbg("exec_sys_register success\n");
651 exit(0);
652 }
653
984263bc
MD
654 /* Make a list of init functions to call. */
655 objlist_init(&initlist);
656 initlist_add_objects(obj_list, preload_tail, &initlist);
657
658 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
659
e9de6dcc
JM
660 map_stacks_exec(NULL);
661
a1eee96a
MD
662 /*
663 * Do NOT call the initlist here, give libc a chance to set up
664 * the initial TLS segment. crt1 will then call _rtld_call_init().
665 */
8ca15ec8 666
984263bc
MD
667 dbg("transferring control to program entry point = %p", obj_main->entry);
668
669 /* Return the exit procedure and the program entry point. */
670 *exit_proc = rtld_exit;
671 *objp = obj_main;
672 return (func_ptr_type) obj_main->entry;
673}
674
a1eee96a
MD
675/*
676 * Call the initialization list for dynamically loaded libraries.
677 * (called from crt1.c).
678 */
679void
680_rtld_call_init(void)
681{
fcf53d9b 682 RtldLockState lockstate;
35b2b265 683 Obj_Entry *obj;
fcf53d9b
JM
684
685 wlock_acquire(rtld_bind_lock, &lockstate);
686 objlist_call_init(&initlist, &lockstate);
a1eee96a 687 objlist_clear(&initlist);
35b2b265
JM
688 dbg("loading filtees");
689 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
690 if (ld_loadfltr || obj->z_loadfltr)
691 load_filtees(obj, 0, &lockstate);
692 }
fcf53d9b 693 lock_release(rtld_bind_lock, &lockstate);
a1eee96a
MD
694}
695
984263bc 696Elf_Addr
4648abf3 697_rtld_bind(Obj_Entry *obj, Elf_Size reloff, void *stack)
984263bc
MD
698{
699 const Elf_Rel *rel;
700 const Elf_Sym *def;
701 const Obj_Entry *defobj;
702 Elf_Addr *where;
703 Elf_Addr target;
fcf53d9b 704 RtldLockState lockstate;
984263bc 705
fcf53d9b
JM
706 rlock_acquire(rtld_bind_lock, &lockstate);
707 if (sigsetjmp(lockstate.env, 0) != 0)
708 lock_upgrade(rtld_bind_lock, &lockstate);
984263bc
MD
709 if (obj->pltrel)
710 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
711 else
712 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
713
714 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
35b2b265
JM
715 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
716 &lockstate);
984263bc
MD
717 if (def == NULL)
718 die();
719
720 target = (Elf_Addr)(defobj->relocbase + def->st_value);
721
722 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
723 defobj->strtab + def->st_name, basename(obj->path),
724 (void *)target, basename(defobj->path));
38e4b3b6
SS
725
726 /*
727 * If we have a function call tracing hook, and the
728 * hook would like to keep tracing this one function,
729 * prevent the relocation so we will wind up here
730 * the next time again.
731 *
732 * We don't want to functrace calls from the functracer
733 * to avoid recursive loops.
734 */
735 if (rtld_functrace != NULL && obj != rtld_functrace_obj) {
736 if (rtld_functrace(obj->path,
737 defobj->path,
738 defobj->strtab + def->st_name,
739 stack))
35b2b265
JM
740 lock_release(rtld_bind_lock, &lockstate);
741 return target;
38e4b3b6
SS
742 }
743
35b2b265
JM
744 /*
745 * Write the new contents for the jmpslot. Note that depending on
746 * architecture, the value which we need to return back to the
747 * lazy binding trampoline may or may not be the target
748 * address. The value returned from reloc_jmpslot() is the value
749 * that the trampoline needs.
750 */
751 target = reloc_jmpslot(where, target, defobj, obj, rel);
fcf53d9b 752 lock_release(rtld_bind_lock, &lockstate);
984263bc
MD
753 return target;
754}
755
756/*
757 * Error reporting function. Use it like printf. If formats the message
758 * into a buffer, and sets things up so that the next call to dlerror()
759 * will return the message.
760 */
761void
762_rtld_error(const char *fmt, ...)
763{
764 static char buf[512];
765 va_list ap;
766
767 va_start(ap, fmt);
abfcd5b1 768 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
984263bc
MD
769 error_message = buf;
770 va_end(ap);
771}
772
773/*
774 * Return a dynamically-allocated copy of the current error message, if any.
775 */
776static char *
777errmsg_save(void)
778{
779 return error_message == NULL ? NULL : xstrdup(error_message);
780}
781
782/*
783 * Restore the current error message from a copy which was previously saved
784 * by errmsg_save(). The copy is freed.
785 */
786static void
787errmsg_restore(char *saved_msg)
788{
789 if (saved_msg == NULL)
790 error_message = NULL;
791 else {
792 _rtld_error("%s", saved_msg);
793 free(saved_msg);
794 }
795}
796
1c76efe5 797const char *
984263bc
MD
798basename(const char *name)
799{
800 const char *p = strrchr(name, '/');
801 return p != NULL ? p + 1 : name;
802}
803
fcf53d9b
JM
804static struct utsname uts;
805
806static int
807origin_subst_one(char **res, const char *real, const char *kw, const char *subst,
808 char *may_free)
809{
810 const char *p, *p1;
811 char *res1;
812 int subst_len;
813 int kw_len;
814
815 res1 = *res = NULL;
816 p = real;
817 subst_len = kw_len = 0;
818 for (;;) {
819 p1 = strstr(p, kw);
820 if (p1 != NULL) {
821 if (subst_len == 0) {
822 subst_len = strlen(subst);
823 kw_len = strlen(kw);
824 }
825 if (*res == NULL) {
826 *res = xmalloc(PATH_MAX);
827 res1 = *res;
828 }
829 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) {
830 _rtld_error("Substitution of %s in %s cannot be performed",
831 kw, real);
832 if (may_free != NULL)
833 free(may_free);
834 free(res);
835 return (false);
836 }
837 memcpy(res1, p, p1 - p);
838 res1 += p1 - p;
839 memcpy(res1, subst, subst_len);
840 res1 += subst_len;
841 p = p1 + kw_len;
842 } else {
843 if (*res == NULL) {
844 if (may_free != NULL)
845 *res = may_free;
846 else
847 *res = xstrdup(real);
848 return (true);
849 }
850 *res1 = '\0';
851 if (may_free != NULL)
852 free(may_free);
853 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) {
854 free(res);
855 return (false);
856 }
857 return (true);
858 }
859 }
860}
861
862static char *
863origin_subst(const char *real, const char *origin_path)
864{
865 char *res1, *res2, *res3, *res4;
866
867 if (uts.sysname[0] == '\0') {
868 if (uname(&uts) != 0) {
869 _rtld_error("utsname failed: %d", errno);
870 return (NULL);
871 }
872 }
873 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) ||
874 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) ||
875 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) ||
876 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3))
877 return (NULL);
878 return (res4);
879}
880
984263bc
MD
881static void
882die(void)
883{
884 const char *msg = dlerror();
885
886 if (msg == NULL)
887 msg = "Fatal error";
abfcd5b1
JM
888 rtld_fdputstr(STDERR_FILENO, msg);
889 _exit(1);
984263bc
MD
890}
891
892/*
893 * Process a shared object's DYNAMIC section, and save the important
894 * information in its Obj_Entry structure.
895 */
896static void
b566341b
JM
897digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
898 const Elf_Dyn **dyn_soname)
984263bc
MD
899{
900 const Elf_Dyn *dynp;
901 Needed_Entry **needed_tail = &obj->needed;
35b2b265
JM
902 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
903 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
984263bc
MD
904 int plttype = DT_REL;
905
b566341b
JM
906 *dyn_rpath = NULL;
907 *dyn_soname = NULL;
908
fcf53d9b 909 obj->bind_now = false;
984263bc
MD
910 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
911 switch (dynp->d_tag) {
912
913 case DT_REL:
914 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
915 break;
916
917 case DT_RELSZ:
918 obj->relsize = dynp->d_un.d_val;
919 break;
920
921 case DT_RELENT:
922 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
923 break;
924
925 case DT_JMPREL:
926 obj->pltrel = (const Elf_Rel *)
927 (obj->relocbase + dynp->d_un.d_ptr);
928 break;
929
930 case DT_PLTRELSZ:
931 obj->pltrelsize = dynp->d_un.d_val;
932 break;
933
934 case DT_RELA:
935 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
936 break;
937
938 case DT_RELASZ:
939 obj->relasize = dynp->d_un.d_val;
940 break;
941
942 case DT_RELAENT:
943 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
944 break;
945
946 case DT_PLTREL:
947 plttype = dynp->d_un.d_val;
948 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
949 break;
950
951 case DT_SYMTAB:
952 obj->symtab = (const Elf_Sym *)
953 (obj->relocbase + dynp->d_un.d_ptr);
954 break;
955
956 case DT_SYMENT:
957 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
958 break;
959
960 case DT_STRTAB:
961 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
962 break;
963
964 case DT_STRSZ:
965 obj->strsize = dynp->d_un.d_val;
966 break;
967
fcf53d9b
JM
968 case DT_VERNEED:
969 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
970 dynp->d_un.d_val);
971 break;
972
973 case DT_VERNEEDNUM:
974 obj->verneednum = dynp->d_un.d_val;
975 break;
976
977 case DT_VERDEF:
978 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
979 dynp->d_un.d_val);
980 break;
981
982 case DT_VERDEFNUM:
983 obj->verdefnum = dynp->d_un.d_val;
984 break;
985
986 case DT_VERSYM:
987 obj->versyms = (const Elf_Versym *)(obj->relocbase +
988 dynp->d_un.d_val);
989 break;
990
984263bc
MD
991 case DT_HASH:
992 {
d697cc44 993 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
984263bc
MD
994 (obj->relocbase + dynp->d_un.d_ptr);
995 obj->nbuckets = hashtab[0];
996 obj->nchains = hashtab[1];
997 obj->buckets = hashtab + 2;
998 obj->chains = obj->buckets + obj->nbuckets;
999 }
1000 break;
1001
1002 case DT_NEEDED:
1003 if (!obj->rtld) {
1004 Needed_Entry *nep = NEW(Needed_Entry);
1005 nep->name = dynp->d_un.d_val;
1006 nep->obj = NULL;
1007 nep->next = NULL;
1008
1009 *needed_tail = nep;
1010 needed_tail = &nep->next;
1011 }
1012 break;
1013
35b2b265
JM
1014 case DT_FILTER:
1015 if (!obj->rtld) {
1016 Needed_Entry *nep = NEW(Needed_Entry);
1017 nep->name = dynp->d_un.d_val;
1018 nep->obj = NULL;
1019 nep->next = NULL;
1020
1021 *needed_filtees_tail = nep;
1022 needed_filtees_tail = &nep->next;
1023 }
1024 break;
1025
1026 case DT_AUXILIARY:
1027 if (!obj->rtld) {
1028 Needed_Entry *nep = NEW(Needed_Entry);
1029 nep->name = dynp->d_un.d_val;
1030 nep->obj = NULL;
1031 nep->next = NULL;
1032
1033 *needed_aux_filtees_tail = nep;
1034 needed_aux_filtees_tail = &nep->next;
1035 }
1036 break;
1037
984263bc
MD
1038 case DT_PLTGOT:
1039 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1040 break;
1041
1042 case DT_TEXTREL:
1043 obj->textrel = true;
1044 break;
1045
1046 case DT_SYMBOLIC:
1047 obj->symbolic = true;
1048 break;
1049
1050 case DT_RPATH:
167f7029 1051 case DT_RUNPATH: /* XXX: process separately */
984263bc
MD
1052 /*
1053 * We have to wait until later to process this, because we
1054 * might not have gotten the address of the string table yet.
1055 */
b566341b 1056 *dyn_rpath = dynp;
984263bc
MD
1057 break;
1058
1059 case DT_SONAME:
b566341b 1060 *dyn_soname = dynp;
984263bc
MD
1061 break;
1062
1063 case DT_INIT:
fcf53d9b 1064 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
984263bc
MD
1065 break;
1066
1067 case DT_FINI:
fcf53d9b 1068 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
984263bc
MD
1069 break;
1070
1071 case DT_DEBUG:
1072 /* XXX - not implemented yet */
c3098c28
SS
1073 if (!early)
1074 dbg("Filling in DT_DEBUG entry");
984263bc
MD
1075 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1076 break;
1077
167f7029 1078 case DT_FLAGS:
fcf53d9b
JM
1079 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1080 obj->z_origin = true;
167f7029
JS
1081 if (dynp->d_un.d_val & DF_SYMBOLIC)
1082 obj->symbolic = true;
1083 if (dynp->d_un.d_val & DF_TEXTREL)
1084 obj->textrel = true;
1085 if (dynp->d_un.d_val & DF_BIND_NOW)
1086 obj->bind_now = true;
8301820e
JM
1087 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1088 ;*/
167f7029
JS
1089 break;
1090
fcf53d9b
JM
1091 case DT_FLAGS_1:
1092 if (dynp->d_un.d_val & DF_1_NOOPEN)
1093 obj->z_noopen = true;
1094 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1095 obj->z_origin = true;
8301820e
JM
1096 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1097 XXX ;*/
fcf53d9b
JM
1098 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1099 obj->bind_now = true;
1100 if (dynp->d_un.d_val & DF_1_NODELETE)
1101 obj->z_nodelete = true;
35b2b265
JM
1102 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1103 obj->z_loadfltr = true;
fcf53d9b
JM
1104 break;
1105
984263bc 1106 default:
fcf53d9b
JM
1107 if (!early) {
1108 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1109 (long)dynp->d_tag);
1110 }
984263bc
MD
1111 break;
1112 }
1113 }
1114
1115 obj->traced = false;
1116
1117 if (plttype == DT_RELA) {
1118 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1119 obj->pltrel = NULL;
1120 obj->pltrelasize = obj->pltrelsize;
1121 obj->pltrelsize = 0;
1122 }
b566341b
JM
1123}
1124
1125static void
1126digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1127 const Elf_Dyn *dyn_soname)
1128{
984263bc 1129
fcf53d9b
JM
1130 if (obj->z_origin && obj->origin_path == NULL) {
1131 obj->origin_path = xmalloc(PATH_MAX);
1132 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1133 die();
1134 }
1135
1136 if (dyn_rpath != NULL) {
1137 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1138 if (obj->z_origin)
1139 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1140 }
1141
1142 if (dyn_soname != NULL)
1143 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
984263bc
MD
1144}
1145
b566341b
JM
1146static void
1147digest_dynamic(Obj_Entry *obj, int early)
1148{
1149 const Elf_Dyn *dyn_rpath;
1150 const Elf_Dyn *dyn_soname;
1151
1152 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname);
1153 digest_dynamic2(obj, dyn_rpath, dyn_soname);
1154}
1155
984263bc
MD
1156/*
1157 * Process a shared object's program header. This is used only for the
1158 * main program, when the kernel has already loaded the main program
1159 * into memory before calling the dynamic linker. It creates and
1160 * returns an Obj_Entry structure.
1161 */
1162static Obj_Entry *
1163digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1164{
1165 Obj_Entry *obj;
1166 const Elf_Phdr *phlimit = phdr + phnum;
1167 const Elf_Phdr *ph;
1168 int nsegs = 0;
1169
1170 obj = obj_new();
1171 for (ph = phdr; ph < phlimit; ph++) {
fcf53d9b
JM
1172 if (ph->p_type != PT_PHDR)
1173 continue;
984263bc 1174
fcf53d9b
JM
1175 obj->phdr = phdr;
1176 obj->phsize = ph->p_memsz;
1177 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1178 break;
1179 }
1180
e9de6dcc
JM
1181 obj->stack_flags = PF_X | PF_R | PF_W;
1182
fcf53d9b
JM
1183 for (ph = phdr; ph < phlimit; ph++) {
1184 switch (ph->p_type) {
984263bc
MD
1185
1186 case PT_INTERP:
fcf53d9b 1187 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
984263bc
MD
1188 break;
1189
1190 case PT_LOAD:
1191 if (nsegs == 0) { /* First load segment */
1192 obj->vaddrbase = trunc_page(ph->p_vaddr);
fcf53d9b 1193 obj->mapbase = obj->vaddrbase + obj->relocbase;
984263bc
MD
1194 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1195 obj->vaddrbase;
1196 } else { /* Last load segment */
1197 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1198 obj->vaddrbase;
1199 }
1200 nsegs++;
1201 break;
1202
1203 case PT_DYNAMIC:
fcf53d9b 1204 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
984263bc 1205 break;
55b88cae
DX
1206
1207 case PT_TLS:
1208 obj->tlsindex = 1;
1209 obj->tlssize = ph->p_memsz;
1210 obj->tlsalign = ph->p_align;
1211 obj->tlsinitsize = ph->p_filesz;
fcf53d9b 1212 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
55b88cae 1213 break;
007f494e 1214
e9de6dcc
JM
1215 case PT_GNU_STACK:
1216 obj->stack_flags = ph->p_flags;
1217 break;
1218
007f494e
JM
1219 case PT_GNU_RELRO:
1220 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1221 obj->relro_size = round_page(ph->p_memsz);
1222 break;
984263bc
MD
1223 }
1224 }
1225 if (nsegs < 1) {
1226 _rtld_error("%s: too few PT_LOAD segments", path);
1227 return NULL;
1228 }
1229
1230 obj->entry = entry;
1231 return obj;
1232}
1233
1234static Obj_Entry *
1235dlcheck(void *handle)
1236{
1237 Obj_Entry *obj;
1238
1239 for (obj = obj_list; obj != NULL; obj = obj->next)
1240 if (obj == (Obj_Entry *) handle)
1241 break;
1242
1243 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1244 _rtld_error("Invalid shared object handle %p", handle);
1245 return NULL;
1246 }
1247 return obj;
1248}
1249
1250/*
1251 * If the given object is already in the donelist, return true. Otherwise
1252 * add the object to the list and return false.
1253 */
1254static bool
1255donelist_check(DoneList *dlp, const Obj_Entry *obj)
1256{
1257 unsigned int i;
1258
1259 for (i = 0; i < dlp->num_used; i++)
1260 if (dlp->objs[i] == obj)
1261 return true;
1262 /*
1263 * Our donelist allocation should always be sufficient. But if
1264 * our threads locking isn't working properly, more shared objects
1265 * could have been loaded since we allocated the list. That should
1266 * never happen, but we'll handle it properly just in case it does.
1267 */
1268 if (dlp->num_used < dlp->num_alloc)
1269 dlp->objs[dlp->num_used++] = obj;
1270 return false;
1271}
1272
1273/*
1274 * Hash function for symbol table lookup. Don't even think about changing
1275 * this. It is specified by the System V ABI.
1276 */
1277unsigned long
1278elf_hash(const char *name)
1279{
1280 const unsigned char *p = (const unsigned char *) name;
1281 unsigned long h = 0;
1282 unsigned long g;
1283
1284 while (*p != '\0') {
1285 h = (h << 4) + *p++;
1286 if ((g = h & 0xf0000000) != 0)
1287 h ^= g >> 24;
1288 h &= ~g;
1289 }
1290 return h;
1291}
1292
1293/*
1294 * Find the library with the given name, and return its full pathname.
1295 * The returned string is dynamically allocated. Generates an error
1296 * message and returns NULL if the library cannot be found.
1297 *
1298 * If the second argument is non-NULL, then it refers to an already-
1299 * loaded shared object, whose library search path will be searched.
1300 *
1301 * The search order is:
984263bc 1302 * LD_LIBRARY_PATH
4e390e27 1303 * rpath in the referencing file
984263bc
MD
1304 * ldconfig hints
1305 * /usr/lib
1306 */
1307static char *
fcf53d9b 1308find_library(const char *xname, const Obj_Entry *refobj)
984263bc
MD
1309{
1310 char *pathname;
fcf53d9b 1311 char *name;
984263bc 1312
fcf53d9b
JM
1313 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1314 if (xname[0] != '/' && !trust) {
984263bc 1315 _rtld_error("Absolute pathname required for shared object \"%s\"",
fcf53d9b 1316 xname);
984263bc
MD
1317 return NULL;
1318 }
fcf53d9b
JM
1319 if (refobj != NULL && refobj->z_origin)
1320 return origin_subst(xname, refobj->origin_path);
1321 else
1322 return xstrdup(xname);
984263bc
MD
1323 }
1324
fcf53d9b
JM
1325 if (libmap_disable || (refobj == NULL) ||
1326 (name = lm_find(refobj->path, xname)) == NULL)
1327 name = (char *)xname;
1328
984263bc
MD
1329 dbg(" Searching for \"%s\"", name);
1330
1331 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1332 (refobj != NULL &&
1333 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1334 (pathname = search_library_path(name, gethints())) != NULL ||
1335 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1336 return pathname;
1337
446c0d3a
JS
1338 if(refobj != NULL && refobj->path != NULL) {
1339 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1340 name, basename(refobj->path));
1341 } else {
1342 _rtld_error("Shared object \"%s\" not found", name);
1343 }
984263bc
MD
1344 return NULL;
1345}
1346
1347/*
1348 * Given a symbol number in a referencing object, find the corresponding
1349 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1350 * no definition was found. Returns a pointer to the Obj_Entry of the
1351 * defining object via the reference parameter DEFOBJ_OUT.
1352 */
1353const Elf_Sym *
1354find_symdef(unsigned long symnum, const Obj_Entry *refobj,
35b2b265
JM
1355 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1356 RtldLockState *lockstate)
984263bc
MD
1357{
1358 const Elf_Sym *ref;
1359 const Elf_Sym *def;
1360 const Obj_Entry *defobj;
35b2b265 1361 SymLook req;
984263bc 1362 const char *name;
35b2b265 1363 int res;
984263bc
MD
1364
1365 /*
1366 * If we have already found this symbol, get the information from
1367 * the cache.
1368 */
1369 if (symnum >= refobj->nchains)
1370 return NULL; /* Bad object */
1371 if (cache != NULL && cache[symnum].sym != NULL) {
1372 *defobj_out = cache[symnum].obj;
1373 return cache[symnum].sym;
1374 }
1375
1376 ref = refobj->symtab + symnum;
1377 name = refobj->strtab + ref->st_name;
35b2b265 1378 def = NULL;
984263bc
MD
1379 defobj = NULL;
1380
0e588128
SS
1381 /*
1382 * We don't have to do a full scale lookup if the symbol is local.
1383 * We know it will bind to the instance in this load module; to
1384 * which we already have a pointer (ie ref). By not doing a lookup,
1385 * we not only improve performance, but it also avoids unresolvable
1386 * symbols when local symbols are not in the hash table.
1387 *
1388 * This might occur for TLS module relocations, which simply use
1389 * symbol 0.
1390 */
1391 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1392 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
c3098c28
SS
1393 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1394 symnum);
1395 }
35b2b265
JM
1396 symlook_init(&req, name);
1397 req.flags = flags;
1398 req.ventry = fetch_ventry(refobj, symnum);
1399 req.lockstate = lockstate;
1400 res = symlook_default(&req, refobj);
1401 if (res == 0) {
1402 def = req.sym_out;
1403 defobj = req.defobj_out;
1404 }
0e588128 1405 } else {
c3098c28
SS
1406 def = ref;
1407 defobj = refobj;
0e588128 1408 }
984263bc
MD
1409
1410 /*
1411 * If we found no definition and the reference is weak, treat the
1412 * symbol as having the value zero.
1413 */
1414 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1415 def = &sym_zero;
1416 defobj = obj_main;
1417 }
1418
1419 if (def != NULL) {
1420 *defobj_out = defobj;
1421 /* Record the information in the cache to avoid subsequent lookups. */
1422 if (cache != NULL) {
1423 cache[symnum].sym = def;
1424 cache[symnum].obj = defobj;
1425 }
fcf53d9b
JM
1426 } else {
1427 if (refobj != &obj_rtld)
1428 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1429 }
984263bc
MD
1430 return def;
1431}
1432
1433/*
1434 * Return the search path from the ldconfig hints file, reading it if
1435 * necessary. Returns NULL if there are problems with the hints file,
1436 * or if the search path there is empty.
1437 */
1438static const char *
1439gethints(void)
1440{
1441 static char *hints;
1442
1443 if (hints == NULL) {
1444 int fd;
1445 struct elfhints_hdr hdr;
1446 char *p;
1447
1448 /* Keep from trying again in case the hints file is bad. */
1449 hints = "";
1450
fcf53d9b 1451 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1)
984263bc
MD
1452 return NULL;
1453 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1454 hdr.magic != ELFHINTS_MAGIC ||
1455 hdr.version != 1) {
1456 close(fd);
1457 return NULL;
1458 }
1459 p = xmalloc(hdr.dirlistlen + 1);
1460 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
fcf53d9b 1461 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) {
984263bc
MD
1462 free(p);
1463 close(fd);
1464 return NULL;
1465 }
1466 hints = p;
1467 close(fd);
1468 }
1469 return hints[0] != '\0' ? hints : NULL;
1470}
1471
1472static void
1473init_dag(Obj_Entry *root)
1474{
1475 DoneList donelist;
1476
fcf53d9b
JM
1477 if (root->dag_inited)
1478 return;
984263bc
MD
1479 donelist_init(&donelist);
1480 init_dag1(root, root, &donelist);
35b2b265 1481 root->dag_inited = true;
984263bc
MD
1482}
1483
1484static void
1485init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp)
1486{
1487 const Needed_Entry *needed;
1488
1489 if (donelist_check(dlp, obj))
1490 return;
fcf53d9b 1491
984263bc
MD
1492 objlist_push_tail(&obj->dldags, root);
1493 objlist_push_tail(&root->dagmembers, obj);
1494 for (needed = obj->needed; needed != NULL; needed = needed->next)
1495 if (needed->obj != NULL)
1496 init_dag1(root, needed->obj, dlp);
1497}
1498
1499/*
1500 * Initialize the dynamic linker. The argument is the address at which
1501 * the dynamic linker has been mapped into memory. The primary task of
1502 * this function is to relocate the dynamic linker.
1503 */
1504static void
b566341b 1505init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
984263bc 1506{
c3098c28 1507 Obj_Entry objtmp; /* Temporary rtld object */
b566341b
JM
1508 const Elf_Dyn *dyn_rpath;
1509 const Elf_Dyn *dyn_soname;
c3098c28 1510
984263bc
MD
1511 /*
1512 * Conjure up an Obj_Entry structure for the dynamic linker.
1513 *
fcf53d9b
JM
1514 * The "path" member can't be initialized yet because string constants
1515 * cannot yet be accessed. Below we will set it correctly.
984263bc 1516 */
4648abf3 1517 memset(&objtmp, 0, sizeof(objtmp));
c3098c28
SS
1518 objtmp.path = NULL;
1519 objtmp.rtld = true;
1520 objtmp.mapbase = mapbase;
984263bc 1521#ifdef PIC
c3098c28 1522 objtmp.relocbase = mapbase;
984263bc 1523#endif
fcf53d9b 1524 if (RTLD_IS_DYNAMIC()) {
c3098c28 1525 objtmp.dynamic = rtld_dynamic(&objtmp);
b566341b 1526 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname);
c3098c28
SS
1527 assert(objtmp.needed == NULL);
1528 assert(!objtmp.textrel);
984263bc
MD
1529
1530 /*
1531 * Temporarily put the dynamic linker entry into the object list, so
1532 * that symbols can be found.
1533 */
984263bc 1534
35b2b265 1535 relocate_objects(&objtmp, true, &objtmp, NULL);
984263bc
MD
1536 }
1537
c3098c28 1538 /* Initialize the object list. */
984263bc 1539 obj_tail = &obj_list;
c3098c28
SS
1540
1541 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1542 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
984263bc 1543
b566341b
JM
1544#ifdef ENABLE_OSRELDATE
1545 if (aux_info[AT_OSRELDATE] != NULL)
1546 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1547#endif
1548
1549 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname);
1550
984263bc 1551 /* Replace the path with a dynamically allocated copy. */
c3098c28 1552 obj_rtld.path = xstrdup(PATH_RTLD);
984263bc
MD
1553
1554 r_debug.r_brk = r_debug_state;
1555 r_debug.r_state = RT_CONSISTENT;
1556}
1557
1558/*
1559 * Add the init functions from a needed object list (and its recursive
1560 * needed objects) to "list". This is not used directly; it is a helper
1561 * function for initlist_add_objects(). The write lock must be held
1562 * when this function is called.
1563 */
1564static void
1565initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1566{
1567 /* Recursively process the successor needed objects. */
1568 if (needed->next != NULL)
1569 initlist_add_neededs(needed->next, list);
1570
1571 /* Process the current needed object. */
1572 if (needed->obj != NULL)
1573 initlist_add_objects(needed->obj, &needed->obj->next, list);
1574}
1575
1576/*
1577 * Scan all of the DAGs rooted in the range of objects from "obj" to
1578 * "tail" and add their init functions to "list". This recurses over
1579 * the DAGs and ensure the proper init ordering such that each object's
1580 * needed libraries are initialized before the object itself. At the
1581 * same time, this function adds the objects to the global finalization
1582 * list "list_fini" in the opposite order. The write lock must be
1583 * held when this function is called.
1584 */
1585static void
1586initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1587{
fcf53d9b 1588 if (obj->init_scanned || obj->init_done)
984263bc 1589 return;
fcf53d9b 1590 obj->init_scanned = true;
984263bc
MD
1591
1592 /* Recursively process the successor objects. */
1593 if (&obj->next != tail)
1594 initlist_add_objects(obj->next, tail, list);
1595
1596 /* Recursively process the needed objects. */
1597 if (obj->needed != NULL)
1598 initlist_add_neededs(obj->needed, list);
1599
1600 /* Add the object to the init list. */
fcf53d9b 1601 if (obj->init != (Elf_Addr)NULL)
984263bc
MD
1602 objlist_push_tail(list, obj);
1603
1604 /* Add the object to the global fini list in the reverse order. */
fcf53d9b 1605 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) {
984263bc 1606 objlist_push_head(&list_fini, obj);
fcf53d9b
JM
1607 obj->on_fini_list = true;
1608 }
984263bc
MD
1609}
1610
fcf53d9b
JM
1611#ifndef FPTR_TARGET
1612#define FPTR_TARGET(f) ((Elf_Addr) (f))
1613#endif
1614
984263bc
MD
1615static bool
1616is_exported(const Elf_Sym *def)
1617{
d697cc44 1618 Elf_Addr value;
984263bc
MD
1619 const func_ptr_type *p;
1620
d697cc44 1621 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value);
fcf53d9b
JM
1622 for (p = exports; *p != NULL; p++)
1623 if (FPTR_TARGET(*p) == value)
984263bc
MD
1624 return true;
1625 return false;
1626}
1627
35b2b265
JM
1628static void
1629free_needed_filtees(Needed_Entry *n)
1630{
1631 Needed_Entry *needed, *needed1;
1632
1633 for (needed = n; needed != NULL; needed = needed->next) {
1634 if (needed->obj != NULL) {
1635 dlclose(needed->obj);
1636 needed->obj = NULL;
1637 }
1638 }
1639 for (needed = n; needed != NULL; needed = needed1) {
1640 needed1 = needed->next;
1641 free(needed);
1642 }
1643}
1644
1645static void
1646unload_filtees(Obj_Entry *obj)
1647{
1648
1649 free_needed_filtees(obj->needed_filtees);
1650 obj->needed_filtees = NULL;
1651 free_needed_filtees(obj->needed_aux_filtees);
1652 obj->needed_aux_filtees = NULL;
1653 obj->filtees_loaded = false;
1654}
1655
1656static void
1657load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags)
1658{
1659
1660 for (; needed != NULL; needed = needed->next) {
1661 needed->obj = dlopen_object(obj->strtab + needed->name, obj,
1662 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
1663 RTLD_LOCAL);
1664 }
1665}
1666
1667static void
1668load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
1669{
1670
1671 lock_restart_for_upgrade(lockstate);
1672 if (!obj->filtees_loaded) {
1673 load_filtee1(obj, obj->needed_filtees, flags);
1674 load_filtee1(obj, obj->needed_aux_filtees, flags);
1675 obj->filtees_loaded = true;
1676 }
1677}
1678
1679static int
1680process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
1681{
1682 Obj_Entry *obj1;
1683
1684 for (; needed != NULL; needed = needed->next) {
1685 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj,
1686 flags & ~RTLD_LO_NOLOAD);
1687 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
1688 return (-1);
1689 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) {
1690 dbg("obj %s nodelete", obj1->path);
1691 init_dag(obj1);
1692 ref_dag(obj1);
1693 obj1->ref_nodel = true;
1694 }
1695 }
1696 return (0);
1697}
1698
984263bc
MD
1699/*
1700 * Given a shared object, traverse its list of needed objects, and load
1701 * each of them. Returns 0 on success. Generates an error message and
1702 * returns -1 on failure.
1703 */
1704static int
fcf53d9b 1705load_needed_objects(Obj_Entry *first, int flags)
984263bc 1706{
35b2b265 1707 Obj_Entry *obj;
984263bc
MD
1708
1709 for (obj = first; obj != NULL; obj = obj->next) {
35b2b265
JM
1710 if (process_needed(obj, obj->needed, flags) == -1)
1711 return (-1);
984263bc 1712 }
fcf53d9b 1713 return (0);
984263bc
MD
1714}
1715
1716static int
1717load_preload_objects(void)
1718{
1719 char *p = ld_preload;
1720 static const char delim[] = " \t:;";
1721
1722 if (p == NULL)
eecd52b2 1723 return 0;
984263bc
MD
1724
1725 p += strspn(p, delim);
1726 while (*p != '\0') {
1727 size_t len = strcspn(p, delim);
984263bc 1728 char savech;
38e4b3b6 1729 Obj_Entry *obj;
35b2b265
JM
1730 SymLook req;
1731 int res;
984263bc
MD
1732
1733 savech = p[len];
1734 p[len] = '\0';
fcf53d9b 1735 obj = load_object(p, NULL, 0);
38e4b3b6 1736 if (obj == NULL)
984263bc
MD
1737 return -1; /* XXX - cleanup */
1738 p[len] = savech;
1739 p += len;
1740 p += strspn(p, delim);
38e4b3b6
SS
1741
1742 /* Check for the magic tracing function */
35b2b265
JM
1743 symlook_init(&req, RTLD_FUNCTRACE);
1744 res = symlook_obj(&req, obj);
1745 if (res == 0) {
1746 rtld_functrace = (void *)(req.defobj_out->relocbase +
1747 req.sym_out->st_value);
1748 rtld_functrace_obj = req.defobj_out;
38e4b3b6 1749 }
984263bc 1750 }
fcf53d9b 1751 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
984263bc
MD
1752 return 0;
1753}
1754
b6a22d96 1755/*
fcf53d9b
JM
1756 * Load a shared object into memory, if it is not already loaded.
1757 *
1758 * Returns a pointer to the Obj_Entry for the object. Returns NULL
1759 * on failure.
b6a22d96
JS
1760 */
1761static Obj_Entry *
fcf53d9b 1762load_object(const char *name, const Obj_Entry *refobj, int flags)
b6a22d96
JS
1763{
1764 Obj_Entry *obj;
fcf53d9b
JM
1765 int fd = -1;
1766 struct stat sb;
1767 char *path;
b6a22d96 1768
fcf53d9b
JM
1769 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1770 if (object_match_name(obj, name))
1771 return obj;
b6a22d96 1772
fcf53d9b
JM
1773 path = find_library(name, refobj);
1774 if (path == NULL)
1775 return NULL;
2d6b58a8 1776
fcf53d9b
JM
1777 /*
1778 * If we didn't find a match by pathname, open the file and check
1779 * again by device and inode. This avoids false mismatches caused
1780 * by multiple links or ".." in pathnames.
1781 *
1782 * To avoid a race, we open the file and use fstat() rather than
1783 * using stat().
1784 */
1785 if ((fd = open(path, O_RDONLY)) == -1) {
2d6b58a8 1786 _rtld_error("Cannot open \"%s\"", path);
fcf53d9b
JM
1787 free(path);
1788 return NULL;
2d6b58a8 1789 }
fcf53d9b 1790 if (fstat(fd, &sb) == -1) {
2d6b58a8 1791 _rtld_error("Cannot fstat \"%s\"", path);
fcf53d9b
JM
1792 close(fd);
1793 free(path);
2d6b58a8
JS
1794 return NULL;
1795 }
fcf53d9b
JM
1796 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1797 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2d6b58a8 1798 break;
fcf53d9b
JM
1799 if (obj != NULL) {
1800 object_add_name(obj, name);
1801 free(path);
1802 close(fd);
1803 return obj;
1804 }
1805 if (flags & RTLD_LO_NOLOAD) {
1806 free(path);
8bdeb8d3 1807 close(fd);
fcf53d9b 1808 return (NULL);
2d6b58a8
JS
1809 }
1810
fcf53d9b
JM
1811 /* First use of this object, so we must map it in */
1812 obj = do_load_object(fd, name, path, &sb, flags);
1813 if (obj == NULL)
1814 free(path);
1815 close(fd);
1816
1817 return obj;
2d6b58a8
JS
1818}
1819
984263bc 1820static Obj_Entry *
fcf53d9b
JM
1821do_load_object(int fd, const char *name, char *path, struct stat *sbp,
1822 int flags)
984263bc
MD
1823{
1824 Obj_Entry *obj;
fcf53d9b 1825 struct statfs fs;
984263bc 1826
fcf53d9b
JM
1827 /*
1828 * but first, make sure that environment variables haven't been
1829 * used to circumvent the noexec flag on a filesystem.
1830 */
1831 if (dangerous_ld_env) {
1832 if (fstatfs(fd, &fs) != 0) {
1833 _rtld_error("Cannot fstatfs \"%s\"", path);
1834 return NULL;
1835 }
1836 if (fs.f_flags & MNT_NOEXEC) {
1837 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
1838 return NULL;
1839 }
984263bc 1840 }
2d6b58a8 1841 dbg("loading \"%s\"", path);
fcf53d9b
JM
1842 obj = map_object(fd, path, sbp);
1843 if (obj == NULL)
2d6b58a8 1844 return NULL;
984263bc 1845
fcf53d9b 1846 object_add_name(obj, name);
2d6b58a8 1847 obj->path = path;
c3098c28 1848 digest_dynamic(obj, 0);
fcf53d9b
JM
1849 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
1850 RTLD_LO_DLOPEN) {
1851 dbg("refusing to load non-loadable \"%s\"", obj->path);
1852 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
1853 munmap(obj->mapbase, obj->mapsize);
1854 obj_free(obj);
1855 return (NULL);
1856 }
984263bc 1857
2d6b58a8
JS
1858 *obj_tail = obj;
1859 obj_tail = &obj->next;
1860 obj_count++;
fcf53d9b 1861 obj_loads++;
2d6b58a8 1862 linkmap_add(obj); /* for GDB & dlinfo() */
e9de6dcc 1863 max_stack_flags |= obj->stack_flags;
984263bc 1864
139b8f34
SW
1865 dbg(" %p .. %p: %s", obj->mapbase,
1866 obj->mapbase + obj->mapsize - 1, obj->path);
2d6b58a8 1867 if (obj->textrel)
fcf53d9b
JM
1868 dbg(" WARNING: %s has impure text", obj->path);
1869 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
1870 obj->path);
984263bc 1871
984263bc
MD
1872 return obj;
1873}
1874
984263bc
MD
1875static Obj_Entry *
1876obj_from_addr(const void *addr)
1877{
984263bc
MD
1878 Obj_Entry *obj;
1879
984263bc 1880 for (obj = obj_list; obj != NULL; obj = obj->next) {
984263bc
MD
1881 if (addr < (void *) obj->mapbase)
1882 continue;
c6873e56 1883 if (addr < (void *) (obj->mapbase + obj->mapsize))
984263bc
MD
1884 return obj;
1885 }
1886 return NULL;
1887}
1888
1889/*
1890 * Call the finalization functions for each of the objects in "list"
fcf53d9b
JM
1891 * belonging to the DAG of "root" and referenced once. If NULL "root"
1892 * is specified, every finalization function will be called regardless
1893 * of the reference count and the list elements won't be freed. All of
1894 * the objects are expected to have non-NULL fini functions.
984263bc
MD
1895 */
1896static void
fcf53d9b 1897objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
984263bc
MD
1898{
1899 Objlist_Entry *elm;
1900 char *saved_msg;
1901
fcf53d9b
JM
1902 assert(root == NULL || root->refcount == 1);
1903
984263bc
MD
1904 /*
1905 * Preserve the current error message since a fini function might
1906 * call into the dynamic linker and overwrite it.
1907 */
1908 saved_msg = errmsg_save();
fcf53d9b
JM
1909 do {
1910 STAILQ_FOREACH(elm, list, link) {
1911 if (root != NULL && (elm->obj->refcount != 1 ||
1912 objlist_find(&root->dagmembers, elm->obj) == NULL))
1913 continue;
1914 dbg("calling fini function for %s at %p", elm->obj->path,
1915 (void *)elm->obj->fini);
1916 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0,
1917 elm->obj->path);
1918 /* Remove object from fini list to prevent recursive invocation. */
1919 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
1920 /*
1921 * XXX: If a dlopen() call references an object while the
1922 * fini function is in progress, we might end up trying to
1923 * unload the referenced object in dlclose() or the object
1924 * won't be unloaded although its fini function has been
1925 * called.
1926 */
1927 lock_release(rtld_bind_lock, lockstate);
1928 call_initfini_pointer(elm->obj, elm->obj->fini);
1929 wlock_acquire(rtld_bind_lock, lockstate);
1930 /* No need to free anything if process is going down. */
1931 if (root != NULL)
1932 free(elm);
1933 /*
1934 * We must restart the list traversal after every fini call
1935 * because a dlclose() call from the fini function or from
1936 * another thread might have modified the reference counts.
1937 */
1938 break;
984263bc 1939 }
fcf53d9b 1940 } while (elm != NULL);
984263bc
MD
1941 errmsg_restore(saved_msg);
1942}
1943
1944/*
1945 * Call the initialization functions for each of the objects in
1946 * "list". All of the objects are expected to have non-NULL init
1947 * functions.
1948 */
1949static void
fcf53d9b 1950objlist_call_init(Objlist *list, RtldLockState *lockstate)
984263bc
MD
1951{
1952 Objlist_Entry *elm;
fcf53d9b 1953 Obj_Entry *obj;
984263bc
MD
1954 char *saved_msg;
1955
fcf53d9b
JM
1956 /*
1957 * Clean init_scanned flag so that objects can be rechecked and
1958 * possibly initialized earlier if any of vectors called below
1959 * cause the change by using dlopen.
1960 */
1961 for (obj = obj_list; obj != NULL; obj = obj->next)
1962 obj->init_scanned = false;
1963
984263bc
MD
1964 /*
1965 * Preserve the current error message since an init function might
1966 * call into the dynamic linker and overwrite it.
1967 */
1968 saved_msg = errmsg_save();
1969 STAILQ_FOREACH(elm, list, link) {
fcf53d9b
JM
1970 if (elm->obj->init_done) /* Initialized early. */
1971 continue;
1972 dbg("calling init function for %s at %p", elm->obj->path,
1973 (void *)elm->obj->init);
1974 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0,
1975 elm->obj->path);
1976 /*
1977 * Race: other thread might try to use this object before current
1978 * one completes the initilization. Not much can be done here
1979 * without better locking.
1980 */
1981 elm->obj->init_done = true;
1982 lock_release(rtld_bind_lock, lockstate);
1983 call_initfini_pointer(elm->obj, elm->obj->init);
1984 wlock_acquire(rtld_bind_lock, lockstate);
984263bc
MD
1985 }
1986 errmsg_restore(saved_msg);
1987}
1988
1989static void
1990objlist_clear(Objlist *list)
1991{
1992 Objlist_Entry *elm;
1993
1994 while (!STAILQ_EMPTY(list)) {
1995 elm = STAILQ_FIRST(list);
1996 STAILQ_REMOVE_HEAD(list, link);
1997 free(elm);
1998 }
1999}
2000
2001static Objlist_Entry *
2002objlist_find(Objlist *list, const Obj_Entry *obj)
2003{
2004 Objlist_Entry *elm;
2005
2006 STAILQ_FOREACH(elm, list, link)
2007 if (elm->obj == obj)
2008 return elm;
2009 return NULL;
2010}
2011
2012static void
2013objlist_init(Objlist *list)
2014{
2015 STAILQ_INIT(list);
2016}
2017
2018static void
2019objlist_push_head(Objlist *list, Obj_Entry *obj)
2020{
2021 Objlist_Entry *elm;
2022
2023 elm = NEW(Objlist_Entry);
2024 elm->obj = obj;
2025 STAILQ_INSERT_HEAD(list, elm, link);
2026}
2027
2028static void
2029objlist_push_tail(Objlist *list, Obj_Entry *obj)
2030{
2031 Objlist_Entry *elm;
2032
2033 elm = NEW(Objlist_Entry);
2034 elm->obj = obj;
2035 STAILQ_INSERT_TAIL(list, elm, link);
2036}
2037
2038static void
2039objlist_remove(Objlist *list, Obj_Entry *obj)
2040{
2041 Objlist_Entry *elm;
2042
2043 if ((elm = objlist_find(list, obj)) != NULL) {
2044 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2045 free(elm);
2046 }
2047}
2048
984263bc
MD
2049/*
2050 * Relocate newly-loaded shared objects. The argument is a pointer to
2051 * the Obj_Entry for the first such object. All objects from the first
2052 * to the end of the list of objects are relocated. Returns 0 on success,
2053 * or -1 on failure.
2054 */
2055static int
35b2b265
JM
2056relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2057 RtldLockState *lockstate)
984263bc
MD
2058{
2059 Obj_Entry *obj;
2060
2061 for (obj = first; obj != NULL; obj = obj->next) {
c3098c28 2062 if (obj != rtldobj)
984263bc
MD
2063 dbg("relocating \"%s\"", obj->path);
2064 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL ||
2065 obj->symtab == NULL || obj->strtab == NULL) {
2066 _rtld_error("%s: Shared object has no run-time symbol table",
2067 obj->path);
2068 return -1;
2069 }
2070
2071 if (obj->textrel) {
2072 /* There are relocations to the write-protected text segment. */
2073 if (mprotect(obj->mapbase, obj->textsize,
2074 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2075 _rtld_error("%s: Cannot write-enable text segment: %s",
2076 obj->path, strerror(errno));
2077 return -1;
2078 }
2079 }
2080
2081 /* Process the non-PLT relocations. */
35b2b265 2082 if (reloc_non_plt(obj, rtldobj, lockstate))
984263bc
MD
2083 return -1;
2084
4b89341e
MD
2085 /*
2086 * Reprotect the text segment. Make sure it is included in the
2087 * core dump since we modified it. This unfortunately causes the
2088 * entire text segment to core-out but we don't have much of a
2089 * choice. We could try to only reenable core dumps on pages
2090 * in which relocations occured but that is likely most of the text
2091 * pages anyway, and even that would not work because the rest of
2092 * the text pages would wind up as a read-only OBJT_DEFAULT object
2093 * (created due to our modifications) backed by the original OBJT_VNODE
2094 * object, and the ELF coredump code is currently only able to dump
2095 * vnode records for pure vnode-backed mappings, not vnode backings
2096 * to memory objects.
2097 */
2098 if (obj->textrel) {
2099 madvise(obj->mapbase, obj->textsize, MADV_CORE);
984263bc
MD
2100 if (mprotect(obj->mapbase, obj->textsize,
2101 PROT_READ|PROT_EXEC) == -1) {
2102 _rtld_error("%s: Cannot write-protect text segment: %s",
2103 obj->path, strerror(errno));
2104 return -1;
2105 }
2106 }
2107
2108 /* Process the PLT relocations. */
2109 if (reloc_plt(obj) == -1)
2110 return -1;
2111 /* Relocate the jump slots if we are doing immediate binding. */
167f7029 2112 if (obj->bind_now || bind_now)
35b2b265 2113 if (reloc_jmpslots(obj, lockstate) == -1)
984263bc
MD
2114 return -1;
2115
007f494e
JM
2116 /* Set the special PLT or GOT entries. */
2117 init_pltgot(obj);
984263bc
MD
2118
2119 /*
2120 * Set up the magic number and version in the Obj_Entry. These
2121 * were checked in the crt1.o from the original ElfKit, so we
2122 * set them for backward compatibility.
2123 */
2124 obj->magic = RTLD_MAGIC;
2125 obj->version = RTLD_VERSION;
2126
007f494e
JM
2127 /*
2128 * Set relocated data to read-only status if protection specified
2129 */
2130
2131 if (obj->relro_size) {
2132 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) {
2133 _rtld_error("%s: Cannot enforce relro relocation: %s",
2134 obj->path, strerror(errno));
2135 return -1;
2136 }
2137 }
984263bc
MD
2138 }
2139
0c151ba0 2140 return (0);
984263bc
MD
2141}
2142
2143/*
2144 * Cleanup procedure. It will be called (by the atexit mechanism) just
2145 * before the process exits.
2146 */
2147static void
2148rtld_exit(void)
2149{
fcf53d9b 2150 RtldLockState lockstate;
984263bc 2151
fcf53d9b 2152 wlock_acquire(rtld_bind_lock, &lockstate);
984263bc 2153 dbg("rtld_exit()");
fcf53d9b 2154 objlist_call_fini(&list_fini, NULL, &lockstate);
984263bc 2155 /* No need to remove the items from the list, since we are exiting. */
fcf53d9b
JM
2156 if (!libmap_disable)
2157 lm_fini();
2158 lock_release(rtld_bind_lock, &lockstate);
984263bc
MD
2159}
2160
2161static void *
2162path_enumerate(const char *path, path_enum_proc callback, void *arg)
2163{
2164 if (path == NULL)
2165 return (NULL);
2166
2167 path += strspn(path, ":;");
2168 while (*path != '\0') {
2169 size_t len;
2170 char *res;
2171
2172 len = strcspn(path, ":;");
2173 res = callback(path, len, arg);
2174
2175 if (res != NULL)
2176 return (res);
2177
2178 path += len;
2179 path += strspn(path, ":;");
2180 }
2181
2182 return (NULL);
2183}
2184
2185struct try_library_args {
2186 const char *name;
2187 size_t namelen;
2188 char *buffer;
2189 size_t buflen;
2190};
2191
2192static void *
2193try_library_path(const char *dir, size_t dirlen, void *param)
2194{
2195 struct try_library_args *arg;
2196
2197 arg = param;
2198 if (*dir == '/' || trust) {
2199 char *pathname;
2200
2201 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2202 return (NULL);
2203
2204 pathname = arg->buffer;
2205 strncpy(pathname, dir, dirlen);
2206 pathname[dirlen] = '/';
2207 strcpy(pathname + dirlen + 1, arg->name);
2208
2209 dbg(" Trying \"%s\"", pathname);
2210 if (access(pathname, F_OK) == 0) { /* We found it */
2211 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2212 strcpy(pathname, arg->buffer);
2213 return (pathname);
2214 }
2215 }
2216 return (NULL);
2217}
2218
2219static char *
2220search_library_path(const char *name, const char *path)
2221{
2222 char *p;
2223 struct try_library_args arg;
2224
2225 if (path == NULL)
2226 return NULL;
2227
2228 arg.name = name;
2229 arg.namelen = strlen(name);
2230 arg.buffer = xmalloc(PATH_MAX);
2231 arg.buflen = PATH_MAX;
2232
2233 p = path_enumerate(path, try_library_path, &arg);
2234
2235 free(arg.buffer);
2236
2237 return (p);
2238}
2239
2240int
2241dlclose(void *handle)
2242{
2243 Obj_Entry *root;
fcf53d9b 2244 RtldLockState lockstate;
984263bc 2245
fcf53d9b 2246 wlock_acquire(rtld_bind_lock, &lockstate);
984263bc
MD
2247 root = dlcheck(handle);
2248 if (root == NULL) {
fcf53d9b 2249 lock_release(rtld_bind_lock, &lockstate);
984263bc
MD
2250 return -1;
2251 }
fcf53d9b
JM
2252 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2253 root->path);
984263bc
MD
2254
2255 /* Unreference the object and its dependencies. */
2256 root->dl_refcount--;
139b8f34 2257
fcf53d9b 2258 if (root->refcount == 1) {
984263bc 2259 /*
fcf53d9b
JM
2260 * The object will be no longer referenced, so we must unload it.
2261 * First, call the fini functions.
984263bc 2262 */
fcf53d9b
JM
2263 objlist_call_fini(&list_fini, root, &lockstate);
2264
2265 unref_dag(root);
984263bc
MD
2266
2267 /* Finish cleaning up the newly-unreferenced objects. */
2268 GDB_STATE(RT_DELETE,&root->linkmap);
2269 unload_object(root);
2270 GDB_STATE(RT_CONSISTENT,NULL);
fcf53d9b
JM
2271 } else
2272 unref_dag(root);
2273
2274 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2275 lock_release(rtld_bind_lock, &lockstate);
984263bc
MD
2276 return 0;
2277}
2278
fcf53d9b 2279char *
984263bc
MD
2280dlerror(void)
2281{
2282 char *msg = error_message;
2283 error_message = NULL;
2284 return msg;
2285}
2286
984263bc
MD
2287void *
2288dlopen(const char *name, int mode)
2289{
35b2b265 2290 int lo_flags;
984263bc 2291
fcf53d9b 2292 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
984263bc
MD
2293 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2294 if (ld_tracing != NULL)
2295 environ = (char **)*get_program_var_addr("environ");
fcf53d9b
JM
2296 lo_flags = RTLD_LO_DLOPEN;
2297 if (mode & RTLD_NODELETE)
2298 lo_flags |= RTLD_LO_NODELETE;
2299 if (mode & RTLD_NOLOAD)
2300 lo_flags |= RTLD_LO_NOLOAD;
2301 if (ld_tracing != NULL)
2302 lo_flags |= RTLD_LO_TRACE;
984263bc 2303
35b2b265
JM
2304 return (dlopen_object(name, obj_main, lo_flags,
2305 mode & (RTLD_MODEMASK | RTLD_GLOBAL)));
2306}
2307
2308static Obj_Entry *
2309dlopen_object(const char *name, Obj_Entry *refobj, int lo_flags, int mode)
2310{
2311 Obj_Entry **old_obj_tail;
2312 Obj_Entry *obj;
2313 Objlist initlist;
2314 RtldLockState lockstate;
2315 int result;
2316
984263bc
MD
2317 objlist_init(&initlist);
2318
fcf53d9b 2319 wlock_acquire(rtld_bind_lock, &lockstate);
984263bc
MD
2320 GDB_STATE(RT_ADD,NULL);
2321
2322 old_obj_tail = obj_tail;
2323 obj = NULL;
2324 if (name == NULL) {
2325 obj = obj_main;
2326 obj->refcount++;
2327 } else {
35b2b265 2328 obj = load_object(name, refobj, lo_flags);
984263bc
MD
2329 }
2330
2331 if (obj) {
2332 obj->dl_refcount++;
139b8f34 2333 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
984263bc 2334 objlist_push_tail(&list_global, obj);
984263bc
MD
2335 if (*old_obj_tail != NULL) { /* We loaded something new. */
2336 assert(*old_obj_tail == obj);
35b2b265 2337 result = load_needed_objects(obj, lo_flags & RTLD_LO_DLOPEN);
fcf53d9b
JM
2338 init_dag(obj);
2339 ref_dag(obj);
2340 if (result != -1)
2341 result = rtld_verify_versions(&obj->dagmembers);
984263bc
MD
2342 if (result != -1 && ld_tracing)
2343 goto trace;
35b2b265
JM
2344 if (result == -1 || (relocate_objects(obj, (mode & RTLD_MODEMASK)
2345 == RTLD_NOW, &obj_rtld, &lockstate)) == -1) {
984263bc
MD
2346 obj->dl_refcount--;
2347 unref_dag(obj);
2348 if (obj->refcount == 0)
2349 unload_object(obj);
2350 obj = NULL;
2351 } else {
2352 /* Make list of init functions to call. */
2353 initlist_add_objects(obj, &obj->next, &initlist);
2354 }
fcf53d9b
JM
2355 } else {
2356
2357 /*
2358 * Bump the reference counts for objects on this DAG. If
2359 * this is the first dlopen() call for the object that was
2360 * already loaded as a dependency, initialize the dag
2361 * starting at it.
2362 */
2363 init_dag(obj);
2364 ref_dag(obj);
2365
2366 if ((lo_flags & RTLD_LO_TRACE) != 0)
2367 goto trace;
2368 }
2369 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2370 obj->z_nodelete) && !obj->ref_nodel) {
2371 dbg("obj %s nodelete", obj->path);
2372 ref_dag(obj);
2373 obj->z_nodelete = obj->ref_nodel = true;
2374 }
984263bc
MD
2375 }
2376
fcf53d9b
JM
2377 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2378 name);
984263bc
MD
2379 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2380
e9de6dcc
JM
2381 map_stacks_exec(&lockstate);
2382
fcf53d9b
JM
2383 /* Call the init functions. */
2384 objlist_call_init(&initlist, &lockstate);
984263bc 2385 objlist_clear(&initlist);
fcf53d9b 2386 lock_release(rtld_bind_lock, &lockstate);
984263bc
MD
2387 return obj;
2388trace:
2389 trace_loaded_objects(obj);
fcf53d9b 2390 lock_release(rtld_bind_lock, &lockstate);
984263bc
MD
2391 exit(0);
2392}
2393
fcf53d9b
JM
2394static void *
2395do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
2396 int flags)
984263bc 2397{
fcf53d9b
JM
2398 DoneList donelist;
2399 const Obj_Entry *obj, *defobj;
35b2b265
JM
2400 const Elf_Sym *def;
2401 SymLook req;
fcf53d9b 2402 RtldLockState lockstate;
35b2b265 2403 int res;
984263bc 2404
984263bc
MD
2405 def = NULL;
2406 defobj = NULL;
35b2b265
JM
2407 symlook_init(&req, name);
2408 req.ventry = ve;
2409 req.flags = flags | SYMLOOK_IN_PLT;
2410 req.lockstate = &lockstate;
984263bc 2411
fcf53d9b
JM
2412 rlock_acquire(rtld_bind_lock, &lockstate);
2413 if (sigsetjmp(lockstate.env, 0) != 0)
2414 lock_upgrade(rtld_bind_lock, &lockstate);
984263bc
MD
2415 if (handle == NULL || handle == RTLD_NEXT ||
2416 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
984263bc 2417
984263bc
MD
2418 if ((obj = obj_from_addr(retaddr)) == NULL) {
2419 _rtld_error("Cannot determine caller's shared object");
fcf53d9b 2420 lock_release(rtld_bind_lock, &lockstate);
984263bc
MD
2421 return NULL;
2422 }
2423 if (handle == NULL) { /* Just the caller's shared object. */
35b2b265
JM
2424 res = symlook_obj(&req, obj);
2425 if (res == 0) {
2426 def = req.sym_out;
2427 defobj = req.defobj_out;
2428 }
984263bc
MD
2429 } else if (handle == RTLD_NEXT || /* Objects after caller's */
2430 handle == RTLD_SELF) { /* ... caller included */
2431 if (handle == RTLD_NEXT)
2432 obj = obj->next;
2433 for (; obj != NULL; obj = obj->next) {
35b2b265
JM
2434 res = symlook_obj(&req, obj);
2435 if (res == 0) {
2436 if (def == NULL ||
2437 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
2438 def = req.sym_out;
2439 defobj = req.defobj_out;
fcf53d9b
JM
2440 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
2441 break;
2442 }
2443 }
2444 }
2445 /*
2446 * Search the dynamic linker itself, and possibly resolve the
2447 * symbol from there. This is how the application links to
2448 * dynamic linker services such as dlopen.
2449 */
2450 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
35b2b265
JM
2451 res = symlook_obj(&req, &obj_rtld);
2452 if (res == 0 && is_exported(req.sym_out)) {
2453 def = req.sym_out;
2454 defobj = req.defobj_out;
984263bc
MD
2455 }
2456 }
2457 } else {
2458 assert(handle == RTLD_DEFAULT);
35b2b265
JM
2459 res = symlook_default(&req, obj);
2460 if (res == 0) {
2461 defobj = req.defobj_out;
2462 def = req.sym_out;
2463 }
984263bc
MD
2464 }
2465 } else {
2466 if ((obj = dlcheck(handle)) == NULL) {
fcf53d9b 2467 lock_release(rtld_bind_lock, &lockstate);
984263bc
MD
2468 return NULL;
2469 }
2470
fb0c631e 2471 donelist_init(&donelist);
984263bc 2472 if (obj->mainprog) {
984263bc 2473 /* Search main program and all libraries loaded by it. */
35b2b265
JM
2474 res = symlook_list(&req, &list_main, &donelist);
2475 if (res == 0) {
2476 def = req.sym_out;
2477 defobj = req.defobj_out;
2478 } else {
fcf53d9b 2479 /*
35b2b265
JM
2480 * We do not distinguish between 'main' object and
2481 * global scope. If symbol is not defined by objects
2482 * loaded at startup, continue search among
2483 * dynamically loaded objects with RTLD_GLOBAL scope.
fcf53d9b 2484 */
35b2b265
JM
2485 res = symlook_list(&req, &list_global, &donelist);
2486 if (res == 0) {
2487 def = req.sym_out;
2488 defobj = req.defobj_out;
2489 }
2490 }
984263bc 2491 } else {
cebaf0af
SS
2492 Needed_Entry fake;
2493
fcf53d9b 2494 /* Search the whole DAG rooted at the given object. */
cebaf0af
SS
2495 fake.next = NULL;
2496 fake.obj = (Obj_Entry *)obj;
2497 fake.name = 0;
35b2b265
JM
2498 res = symlook_needed(&req, &fake, &donelist);
2499 if (res == 0) {
2500 def = req.sym_out;
2501 defobj = req.defobj_out;
2502 }
984263bc
MD
2503 }
2504 }
2505
2506 if (def != NULL) {
fcf53d9b
JM
2507 lock_release(rtld_bind_lock, &lockstate);
2508
2509 /*
2510 * The value required by the caller is derived from the value
2511 * of the symbol. For the ia64 architecture, we need to
2512 * construct a function descriptor which the caller can use to
2513 * call the function with the right 'gp' value. For other
2514 * architectures and for non-functions, the value is simply
2515 * the relocated value of the symbol.
2516 */
2517 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
0c151ba0 2518 return (make_function_pointer(def, defobj));
fcf53d9b 2519 else
0c151ba0 2520 return (defobj->relocbase + def->st_value);
984263bc
MD
2521 }
2522
2523 _rtld_error("Undefined symbol \"%s\"", name);
fcf53d9b 2524 lock_release(rtld_bind_lock, &lockstate);
984263bc
MD
2525 return NULL;
2526}
2527
fcf53d9b
JM
2528void *
2529dlsym(void *handle, const char *name)
2530{
2531 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
2532 SYMLOOK_DLSYM);
2533}
2534
2535dlfunc_t
2536dlfunc(void *handle, const char *name)
2537{
2538 union {
2539 void *d;
2540 dlfunc_t f;
2541 } rv;
2542
2543 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
2544 SYMLOOK_DLSYM);
2545 return (rv.f);
2546}
2547
2548void *
2549dlvsym(void *handle, const char *name, const char *version)
2550{
2551 Ver_Entry ventry;
2552
2553 ventry.name = version;
2554 ventry.file = NULL;
2555 ventry.hash = elf_hash(version);
2556 ventry.flags= 0;
2557 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
2558 SYMLOOK_DLSYM);
2559}
2560
2561int
2562_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
2563{
2564 const Obj_Entry *obj;
2565 RtldLockState lockstate;
2566
2567 rlock_acquire(rtld_bind_lock, &lockstate);
2568 obj = obj_from_addr(addr);
2569 if (obj == NULL) {
2570 _rtld_error("No shared object contains address");
2571 lock_release(rtld_bind_lock, &lockstate);
2572 return (0);
2573 }
2574 rtld_fill_dl_phdr_info(obj, phdr_info);
2575 lock_release(rtld_bind_lock, &lockstate);
2576 return (1);
2577}
2578
984263bc
MD
2579int
2580dladdr(const void *addr, Dl_info *info)
2581{
2582 const Obj_Entry *obj;
2583 const Elf_Sym *def;
2584 void *symbol_addr;
2585 unsigned long symoffset;
fcf53d9b
JM
2586 RtldLockState lockstate;
2587
2588 rlock_acquire(rtld_bind_lock, &lockstate);
984263bc
MD
2589 obj = obj_from_addr(addr);
2590 if (obj == NULL) {
2591 _rtld_error("No shared object contains address");
fcf53d9b 2592 lock_release(rtld_bind_lock, &lockstate);
984263bc
MD
2593 return 0;
2594 }
2595 info->dli_fname = obj->path;
2596 info->dli_fbase = obj->mapbase;
60233e58 2597 info->dli_saddr = NULL;
984263bc
MD
2598 info->dli_sname = NULL;
2599
2600 /*
2601 * Walk the symbol list looking for the symbol whose address is
2602 * closest to the address sent in.
2603 */
2604 for (symoffset = 0; symoffset < obj->nchains; symoffset++) {
2605 def = obj->symtab + symoffset;
2606
2607 /*
2608 * For skip the symbol if st_shndx is either SHN_UNDEF or
2609 * SHN_COMMON.
2610 */
2611 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
2612 continue;
2613
2614 /*
2615 * If the symbol is greater than the specified address, or if it
2616 * is further away from addr than the current nearest symbol,
2617 * then reject it.
2618 */
2619 symbol_addr = obj->relocbase + def->st_value;
2620 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
2621 continue;
2622
2623 /* Update our idea of the nearest symbol. */
2624 info->dli_sname = obj->strtab + def->st_name;
2625 info->dli_saddr = symbol_addr;
2626
2627 /* Exact match? */
2628 if (info->dli_saddr == addr)
2629 break;
2630 }
fcf53d9b 2631 lock_release(rtld_bind_lock, &lockstate);
984263bc
MD
2632 return 1;
2633}
2634
2635int
2636dlinfo(void *handle, int request, void *p)
2637{
2638 const Obj_Entry *obj;
fcf53d9b 2639 RtldLockState lockstate;
984263bc
MD
2640 int error;
2641
fcf53d9b 2642 rlock_acquire(rtld_bind_lock, &lockstate);
984263bc
MD
2643
2644 if (handle == NULL || handle == RTLD_SELF) {
2645 void *retaddr;
2646
2647 retaddr = __builtin_return_address(0); /* __GNUC__ only */
2648 if ((obj = obj_from_addr(retaddr)) == NULL)
2649 _rtld_error("Cannot determine caller's shared object");
2650 } else
2651 obj = dlcheck(handle);
2652
2653 if (obj == NULL) {
fcf53d9b 2654 lock_release(rtld_bind_lock, &lockstate);
984263bc
MD
2655 return (-1);
2656 }
2657
2658 error = 0;
2659 switch (request) {
2660 case RTLD_DI_LINKMAP:
2661 *((struct link_map const **)p) = &obj->linkmap;
2662 break;
2663 case RTLD_DI_ORIGIN:
2664 error = rtld_dirname(obj->path, p);
2665 break;
2666
2667 case RTLD_DI_SERINFOSIZE:
2668 case RTLD_DI_SERINFO:
2669 error = do_search_info(obj, request, (struct dl_serinfo *)p);
2670 break;
2671
2672 default:
2673 _rtld_error("Invalid request %d passed to dlinfo()", request);
2674 error = -1;
2675 }
2676
fcf53d9b
JM
2677 lock_release(rtld_bind_lock, &lockstate);
2678
2679 return (error);
2680}
2681
2682static void
2683rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
2684{
2685
2686 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
2687 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
2688 STAILQ_FIRST(&obj->names)->name : obj->path;
2689 phdr_info->dlpi_phdr = obj->phdr;
2690 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
2691 phdr_info->dlpi_tls_modid = obj->tlsindex;
2692 phdr_info->dlpi_tls_data = obj->tlsinit;
2693 phdr_info->dlpi_adds = obj_loads;
2694 phdr_info->dlpi_subs = obj_loads - obj_count;
2695}
2696
2697int
2698dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
2699{
2700 struct dl_phdr_info phdr_info;
2701 const Obj_Entry *obj;
2702 RtldLockState bind_lockstate, phdr_lockstate;
2703 int error;
2704
2705 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
2706 rlock_acquire(rtld_bind_lock, &bind_lockstate);
2707
2708 error = 0;
2709
2710 for (obj = obj_list; obj != NULL; obj = obj->next) {
2711 rtld_fill_dl_phdr_info(obj, &phdr_info);
2712 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
2713 break;
2714
2715 }
2716 lock_release(rtld_bind_lock, &bind_lockstate);
2717 lock_release(rtld_phdr_lock, &phdr_lockstate);
984263bc
MD
2718
2719 return (error);
2720}
2721
2722struct fill_search_info_args {
2723 int request;
2724 unsigned int flags;
2725 Dl_serinfo *serinfo;
2726 Dl_serpath *serpath;
2727 char *strspace;
2728};
2729
2730static void *
2731fill_search_info(const char *dir, size_t dirlen, void *param)
2732{
2733 struct fill_search_info_args *arg;
2734
2735 arg = param;
2736
2737 if (arg->request == RTLD_DI_SERINFOSIZE) {
2738 arg->serinfo->dls_cnt ++;
fcf53d9b 2739 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1;
984263bc
MD
2740 } else {
2741 struct dl_serpath *s_entry;
2742
2743 s_entry = arg->serpath;
2744 s_entry->dls_name = arg->strspace;
2745 s_entry->dls_flags = arg->flags;
2746
2747 strncpy(arg->strspace, dir, dirlen);
2748 arg->strspace[dirlen] = '\0';
2749
2750 arg->strspace += dirlen + 1;
2751 arg->serpath++;
2752 }
2753
2754 return (NULL);
2755}
2756
2757static int
2758do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
2759{
2760 struct dl_serinfo _info;
2761 struct fill_search_info_args args;
2762
2763 args.request = RTLD_DI_SERINFOSIZE;
2764 args.serinfo = &_info;
2765
2766 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2767 _info.dls_cnt = 0;
2768
2769 path_enumerate(ld_library_path, fill_search_info, &args);
2770 path_enumerate(obj->rpath, fill_search_info, &args);
2771 path_enumerate(gethints(), fill_search_info, &args);
2772 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
2773
2774
2775 if (request == RTLD_DI_SERINFOSIZE) {
2776 info->dls_size = _info.dls_size;
2777 info->dls_cnt = _info.dls_cnt;
2778 return (0);
2779 }
2780
2781 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
2782 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
2783 return (-1);
2784 }
2785
2786 args.request = RTLD_DI_SERINFO;
2787 args.serinfo = info;
2788 args.serpath = &info->dls_serpath[0];
2789 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
2790
2791 args.flags = LA_SER_LIBPATH;
2792 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
2793 return (-1);
2794
2795 args.flags = LA_SER_RUNPATH;
2796 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
2797 return (-1);
2798
2799 args.flags = LA_SER_CONFIG;
2800 if (path_enumerate(gethints(), fill_search_info, &args) != NULL)
2801 return (-1);
2802
2803 args.flags = LA_SER_DEFAULT;
2804 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
2805 return (-1);
2806 return (0);
2807}
2808
2809static int
2810rtld_dirname(const char *path, char *bname)
2811{
2812 const char *endp;
2813
2814 /* Empty or NULL string gets treated as "." */
2815 if (path == NULL || *path == '\0') {
2816 bname[0] = '.';
2817 bname[1] = '\0';
2818 return (0);
2819 }
2820
2821 /* Strip trailing slashes */
2822 endp = path + strlen(path) - 1;
2823 while (endp > path && *endp == '/')
2824 endp--;
2825
2826 /* Find the start of the dir */
2827 while (endp > path && *endp != '/')
2828 endp--;
2829
2830 /* Either the dir is "/" or there are no slashes */
2831 if (endp == path) {
2832 bname[0] = *endp == '/' ? '/' : '.';
2833 bname[1] = '\0';
2834 return (0);
2835 } else {
2836 do {
2837 endp--;
2838 } while (endp > path && *endp == '/');
2839 }
2840
2841 if (endp - path + 2 > PATH_MAX)
2842 {
2843 _rtld_error("Filename is too long: %s", path);
2844 return(-1);
2845 }
2846
2847 strncpy(bname, path, endp - path + 1);
2848 bname[endp - path + 1] = '\0';
2849 return (0);
2850}
2851
fcf53d9b
JM
2852static int
2853rtld_dirname_abs(const char *path, char *base)
2854{
2855 char base_rel[PATH_MAX];
2856
2857 if (rtld_dirname(path, base) == -1)
2858 return (-1);
2859 if (base[0] == '/')
2860 return (0);
2861 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
2862 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
2863 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
2864 return (-1);
2865 strcpy(base, base_rel);
2866 return (0);
2867}
2868
984263bc
MD
2869static void
2870linkmap_add(Obj_Entry *obj)
2871{
2872 struct link_map *l = &obj->linkmap;
2873 struct link_map *prev;
2874
2875 obj->linkmap.l_name = obj->path;
2876 obj->linkmap.l_addr = obj->mapbase;
2877 obj->linkmap.l_ld = obj->dynamic;
2878#ifdef __mips__
2879 /* GDB needs load offset on MIPS to use the symbols */
2880 obj->linkmap.l_offs = obj->relocbase;
2881#endif
2882
2883 if (r_debug.r_map == NULL) {
2884 r_debug.r_map = l;
2885 return;
2886 }
2887
2888 /*
2889 * Scan to the end of the list, but not past the entry for the
2890 * dynamic linker, which we want to keep at the very end.
2891 */
2892 for (prev = r_debug.r_map;
2893 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
2894 prev = prev->l_next)
2895 ;
2896
2897 /* Link in the new entry. */
2898 l->l_prev = prev;
2899 l->l_next = prev->l_next;
2900 if (l->l_next != NULL)
2901 l->l_next->l_prev = l;
2902 prev->l_next = l;
2903}
2904
2905static void
2906linkmap_delete(Obj_Entry *obj)
2907{
2908 struct link_map *l = &obj->linkmap;
2909
2910 if (l->l_prev == NULL) {
2911 if ((r_debug.r_map = l->l_next) != NULL)
2912 l->l_next->l_prev = NULL;
2913 return;
2914 }
2915
2916 if ((l->l_prev->l_next = l->l_next) != NULL)
2917 l->l_next->l_prev = l->l_prev;
2918}
2919
2920/*
2921 * Function for the debugger to set a breakpoint on to gain control.
2922 *
2923 * The two parameters allow the debugger to easily find and determine
2924 * what the runtime loader is doing and to whom it is doing it.
2925 *
2926 * When the loadhook trap is hit (r_debug_state, set at program
2927 * initialization), the arguments can be found on the stack:
2928 *
2929 * +8 struct link_map *m
2930 * +4 struct r_debug *rd
2931 * +0 RetAddr
2932 */
2933void
2934r_debug_state(struct r_debug* rd, struct link_map *m)
2935{
8301820e
JM
2936 /*
2937 * The following is a hack to force the compiler to emit calls to
2938 * this function, even when optimizing. If the function is empty,
2939 * the compiler is not obliged to emit any code for calls to it,
2940 * even when marked __noinline. However, gdb depends on those
2941 * calls being made.
2942 */
2943 __asm __volatile("" : : : "memory");
984263bc
MD
2944}
2945
2946/*
2947 * Get address of the pointer variable in the main program.
2948 */
2949static const void **
2950get_program_var_addr(const char *name)
2951{
2952 const Obj_Entry *obj;
35b2b265 2953 SymLook req;
984263bc 2954
35b2b265 2955 symlook_init(&req, name);
984263bc 2956 for (obj = obj_main; obj != NULL; obj = obj->next) {
35b2b265
JM
2957 if (symlook_obj(&req, obj) == 0) {
2958 return ((const void **)(req.defobj_out->relocbase +
2959 req.sym_out->st_value));
984263bc
MD
2960 }
2961 }
fcf53d9b 2962 return (NULL);
984263bc
MD
2963}
2964
2965/*
2966 * Set a pointer variable in the main program to the given value. This
2967 * is used to set key variables such as "environ" before any of the
2968 * init functions are called.
2969 */
2970static void
2971set_program_var(const char *name, const void *value)
2972{
2973 const void **addr;
2974
2975 if ((addr = get_program_var_addr(name)) != NULL) {
2976 dbg("\"%s\": *%p <-- %p", name, addr, value);
2977 *addr = value;
2978 }
2979}
2980
8ca15ec8
MD
2981/*
2982 * This is a special version of getenv which is far more efficient
2983 * at finding LD_ environment vars.
2984 */
2985static
2986const char *
2987_getenv_ld(const char *id)
2988{
2989 const char *envp;
2990 int i, j;
2991 int idlen = strlen(id);
2992
2993 if (ld_index == LD_ARY_CACHE)
2994 return(getenv(id));
2995 if (ld_index == 0) {
2996 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) {
2997 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_')
2998 ld_ary[j++] = envp;
2999 }
3000 if (j == 0)
3001 ld_ary[j++] = "";
3002 ld_index = j;
3003 }
3004 for (i = ld_index - 1; i >= 0; --i) {
3005 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=')
3006 return(ld_ary[i] + idlen + 1);
3007 }
3008 return(NULL);
3009}
3010
984263bc
MD
3011/*
3012 * Given a symbol name in a referencing object, find the corresponding
3013 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3014 * no definition was found. Returns a pointer to the Obj_Entry of the
3015 * defining object via the reference parameter DEFOBJ_OUT.
3016 */
35b2b265
JM
3017static int
3018symlook_default(SymLook *req, const Obj_Entry *refobj)
984263bc
MD
3019{
3020 DoneList donelist;
3021 const Elf_Sym *def;
984263bc
MD
3022 const Obj_Entry *defobj;
3023 const Objlist_Entry *elm;
35b2b265
JM
3024 SymLook req1;
3025 int res;
984263bc
MD
3026 def = NULL;
3027 defobj = NULL;
3028 donelist_init(&donelist);
35b2b265 3029 symlook_init_from_req(&req1, req);
984263bc
MD
3030
3031 /* Look first in the referencing object if linked symbolically. */
3032 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
35b2b265
JM
3033 res = symlook_obj(&req1, refobj);
3034 if (res == 0) {
3035 def = req1.sym_out;
3036 defobj = req1.defobj_out;
3037 assert(defobj != NULL);
984263bc
MD
3038 }
3039 }
3040
3041 /* Search all objects loaded at program start up. */
3042 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
35b2b265
JM
3043 res = symlook_list(&req1, &list_main, &donelist);
3044 if (res == 0 &&
3045 (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3046 def = req1.sym_out;
3047 defobj = req1.defobj_out;
3048 assert(defobj != NULL);
984263bc
MD
3049 }
3050 }
3051
3052 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3053 STAILQ_FOREACH(elm, &list_global, link) {
3054 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK)
3055 break;
35b2b265
JM
3056 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3057 if (res == 0 &&
3058 (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3059 def = req1.sym_out;
3060 defobj = req1.defobj_out;
3061 assert(defobj != NULL);
984263bc
MD
3062 }
3063 }
3064
3065 /* Search all dlopened DAGs containing the referencing object. */
3066 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3067 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK)
3068 break;
35b2b265
JM
3069 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3070 if (res == 0 &&
3071 (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3072 def = req1.sym_out;
3073 defobj = req1.defobj_out;
3074 assert(defobj != NULL);
984263bc
MD
3075 }
3076 }
3077
3078 /*
3079 * Search the dynamic linker itself, and possibly resolve the
3080 * symbol from there. This is how the application links to
3081 * dynamic linker services such as dlopen. Only the values listed
3082 * in the "exports" array can be resolved from the dynamic linker.
3083 */
3084 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
35b2b265
JM
3085 res = symlook_obj(&req1, &obj_rtld);
3086 if (res == 0 && is_exported(req1.sym_out)) {
3087 def = req1.sym_out;
3088 defobj = req1.defobj_out;
3089 assert(defobj != NULL);
984263bc
MD
3090 }
3091 }
3092
35b2b265
JM
3093 if (def != NULL) {
3094 assert(defobj != NULL);
3095 req->defobj_out = defobj;
3096 req->sym_out = def;
3097 return (0);
3098 }
3099 return (ESRCH);
984263bc
MD
3100}
3101
35b2b265
JM
3102static int
3103symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
984263bc 3104{
984263bc
MD
3105 const Elf_Sym *def;
3106 const Obj_Entry *defobj;
3107 const Objlist_Entry *elm;
35b2b265
JM
3108 SymLook req1;
3109 int res;
984263bc
MD
3110
3111 def = NULL;
3112 defobj = NULL;
3113 STAILQ_FOREACH(elm, objlist, link) {
3114 if (donelist_check(dlp, elm->obj))
3115 continue;
35b2b265
JM
3116 symlook_init_from_req(&req1, req);
3117 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3118 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3119 def = req1.sym_out;
3120 defobj = req1.defobj_out;
984263bc
MD
3121 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3122 break;
3123 }
3124 }
3125 }
35b2b265
JM
3126 if (def != NULL) {
3127 req->sym_out = def;
3128 req->defobj_out = defobj;
3129 return (0);
3130 }
3131 return (ESRCH);
984263bc
MD
3132}
3133
cebaf0af
SS
3134/*
3135 * Search the symbol table of a shared object and all objects needed
3136 * by it for a symbol of the given name. Search order is
3137 * breadth-first. Returns a pointer to the symbol, or NULL if no
3138 * definition was found.
3139 */
35b2b265
JM
3140static int
3141symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
cebaf0af
SS
3142{
3143 const Elf_Sym *def, *def_w;
3144 const Needed_Entry *n;
35b2b265
JM
3145 const Obj_Entry *defobj, *defobj1;
3146 SymLook req1;
3147 int res;
fcf53d9b 3148
cebaf0af
SS
3149 def = def_w = NULL;
3150 defobj = NULL;
35b2b265 3151 symlook_init_from_req(&req1, req);
cebaf0af 3152 for (n = needed; n != NULL; n = n->next) {
35b2b265
JM
3153 if (n->obj == NULL || donelist_check(dlp, n->obj) ||
3154 (res = symlook_obj(&req1, n->obj)) != 0)
fcf53d9b 3155 continue;
35b2b265
JM
3156 def = req1.sym_out;
3157 defobj = req1.defobj_out;
fcf53d9b 3158 if (ELF_ST_BIND(def->st_info) != STB_WEAK) {
35b2b265
JM
3159 req->defobj_out = defobj;
3160 req->sym_out = def;
3161 return (0);
cebaf0af
SS
3162 }
3163 }
3164 /*
3165 * There we come when either symbol definition is not found in
3166 * directly needed objects, or found symbol is weak.
3167 */
3168 for (n = needed; n != NULL; n = n->next) {
35b2b265 3169 if (n->obj == NULL)
fcf53d9b 3170 continue;
35b2b265
JM
3171 res = symlook_needed(&req1, n->obj->needed, dlp);
3172 if (res != 0)
fcf53d9b 3173 continue;
35b2b265
JM
3174 def_w = req1.sym_out;
3175 defobj1 = req1.defobj_out;
fcf53d9b
JM
3176 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) {
3177 def = def_w;
3178 defobj = defobj1;
3179 }
3180 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK)
3181 break;
cebaf0af 3182 }
35b2b265
JM
3183 if (def != NULL) {
3184 req->sym_out = def;
3185 req->defobj_out = defobj;
3186 return (0);
3187 }
3188 return (ESRCH);
cebaf0af
SS
3189}
3190
984263bc
MD
3191/*
3192 * Search the symbol table of a single shared object for a symbol of
fcf53d9b 3193 * the given name and version, if requested. Returns a pointer to the
35b2b265
JM
3194 * symbol, or NULL if no definition was found. If the object is
3195 * filter, return filtered symbol from filtee.
984263bc
MD
3196 *
3197 * The symbol's hash value is passed in for efficiency reasons; that
3198 * eliminates many recomputations of the hash value.
3199 */
35b2b265
JM
3200int
3201symlook_obj(SymLook *req, const Obj_Entry *obj)
3202{
3203 DoneList donelist;
3204 SymLook req1;
3205 int res, mres;
3206
3207 mres = symlook_obj1(req, obj);
3208 if (mres == 0) {
3209 if (obj->needed_filtees != NULL) {
3210 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate);
3211 donelist_init(&donelist);
3212 symlook_init_from_req(&req1, req);
3213 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3214 if (res == 0) {
3215 req->sym_out = req1.sym_out;
3216 req->defobj_out = req1.defobj_out;
3217 }
3218 return (res);
3219 }
3220 if (obj->needed_aux_filtees != NULL) {
3221 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate);
3222 donelist_init(&donelist);
3223 symlook_init_from_req(&req1, req);
3224 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3225 if (res == 0) {
3226 req->sym_out = req1.sym_out;
3227 req->defobj_out = req1.defobj_out;
3228 return (res);
3229 }
3230 }
3231 }
3232 return (mres);
3233}
3234
3235static int
3236symlook_obj1(SymLook *req, const Obj_Entry *obj)
984263bc 3237{
fcf53d9b
JM
3238 unsigned long symnum;
3239 const Elf_Sym *vsymp;
3240 Elf_Versym verndx;
3241 int vcount;
984263bc 3242
fcf53d9b 3243 if (obj->buckets == NULL)
35b2b265 3244 return (ESRCH);
984263bc 3245
fcf53d9b
JM
3246 vsymp = NULL;
3247 vcount = 0;
35b2b265 3248 symnum = obj->buckets[req->hash % obj->nbuckets];
fcf53d9b
JM
3249
3250 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
3251 const Elf_Sym *symp;
3252 const char *strp;
3253
3254 if (symnum >= obj->nchains)
35b2b265 3255 return (ESRCH); /* Bad object */
fcf53d9b
JM
3256
3257 symp = obj->symtab + symnum;
3258 strp = obj->strtab + symp->st_name;
3259
3260 switch (ELF_ST_TYPE(symp->st_info)) {
3261 case STT_FUNC:
3262 case STT_NOTYPE:
3263 case STT_OBJECT:
3264 if (symp->st_value == 0)
3265 continue;
3266 /* fallthrough */
3267 case STT_TLS:
3268 if (symp->st_shndx != SHN_UNDEF)
3269 break;
35b2b265 3270 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
fcf53d9b
JM
3271 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3272 break;
3273 /* fallthrough */
3274 default:
3275 continue;
3276 }
35b2b265 3277 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
fcf53d9b 3278 continue;
984263bc 3279
35b2b265 3280 if (req->ventry == NULL) {
fcf53d9b
JM
3281 if (obj->versyms != NULL) {
3282 verndx = VER_NDX(obj->versyms[symnum]);
3283 if (verndx > obj->vernum) {
3284 _rtld_error("%s: symbol %s references wrong version %d",
3285 obj->path, obj->strtab + symnum, verndx);
3286 continue;
3287 }
3288 /*
3289 * If we are not called from dlsym (i.e. this is a normal
3290 * relocation from unversioned binary), accept the symbol
3291 * immediately if it happens to have first version after
3292 * this shared object became versioned. Otherwise, if
3293 * symbol is versioned and not hidden, remember it. If it
3294 * is the only symbol with this name exported by the
3295 * shared object, it will be returned as a match at the
3296 * end of the function. If symbol is global (verndx < 2)
3297 * accept it unconditionally.
3298 */
35b2b265
JM
3299 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3300 verndx == VER_NDX_GIVEN) {
3301 req->sym_out = symp;
3302 req->defobj_out = obj;
3303 return (0);
3304 }
fcf53d9b
JM
3305 else if (verndx >= VER_NDX_GIVEN) {
3306 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) {
3307 if (vsymp == NULL)
3308 vsymp = symp;
3309 vcount ++;
3310 }
3311 continue;
3312 }
3313 }
35b2b265
JM
3314 req->sym_out = symp;
3315 req->defobj_out = obj;
3316 return (0);
fcf53d9b
JM
3317 } else {
3318 if (obj->versyms == NULL) {
35b2b265 3319 if (object_match_name(obj, req->ventry->name)) {
fcf53d9b 3320 _rtld_error("%s: object %s should provide version %s for "
35b2b265
JM
3321 "symbol %s", obj_rtld.path, obj->path,
3322 req->ventry->name, obj->strtab + symnum);
fcf53d9b
JM
3323 continue;
3324 }
3325 } else {
3326 verndx = VER_NDX(obj->versyms[symnum]);
3327 if (verndx > obj->vernum) {
3328 _rtld_error("%s: symbol %s references wrong version %d",
3329 obj->path, obj->strtab + symnum, verndx);
3330 continue;
3331 }
35b2b265
JM
3332 if (obj->vertab[verndx].hash != req->ventry->hash ||
3333 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
fcf53d9b
JM
3334 /*
3335 * Version does not match. Look if this is a global symbol
3336 * and if it is not hidden. If global symbol (verndx < 2)
3337 * is available, use it. Do not return symbol if we are
3338 * called by dlvsym, because dlvsym looks for a specific
3339 * version and default one is not what dlvsym wants.
3340 */
35b2b265 3341 if ((req->flags & SYMLOOK_DLSYM) ||
fcf53d9b
JM
3342 (obj->versyms[symnum] & VER_NDX_HIDDEN) ||
3343 (verndx >= VER_NDX_GIVEN))
3344 continue;
3345 }
3346 }
35b2b265
JM
3347 req->sym_out = symp;
3348 req->defobj_out = obj;
3349 return (0);
984263bc
MD
3350 }
3351 }
35b2b265
JM
3352 if (vcount == 1) {
3353 req->sym_out = vsymp;
3354 req->defobj_out = obj;
3355 return (0);
3356 }
3357 return (ESRCH);
984263bc
MD
3358}
3359
3360static void
3361trace_loaded_objects(Obj_Entry *obj)
3362{
fcf53d9b 3363 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
984263bc
MD
3364 int c;
3365
8ca15ec8 3366 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
984263bc
MD
3367 main_local = "";
3368
8ca15ec8 3369 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL)
984263bc
MD
3370 fmt1 = "\t%o => %p (%x)\n";
3371
8ca15ec8 3372 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL)
984263bc
MD
3373 fmt2 = "\t%o (%x)\n";
3374
fcf53d9b
JM
3375 list_containers = _getenv_ld("LD_TRACE_LOADED_OBJECTS_ALL");
3376
984263bc
MD
3377 for (; obj; obj = obj->next) {
3378 Needed_Entry *needed;
3379 char *name, *path;
3380 bool is_lib;
3381
fcf53d9b 3382 if (list_containers && obj->needed != NULL)
abfcd5b1 3383 rtld_printf("%s:\n", obj->path);
984263bc
MD
3384 for (needed = obj->needed; needed; needed = needed->next) {
3385 if (needed->obj != NULL) {
fcf53d9b 3386 if (needed->obj->traced && !list_containers)
984263bc
MD
3387 continue;
3388 needed->obj->traced = true;
3389 path = needed->obj->path;
3390 } else
3391 path = "not found";
3392
3393 name = (char *)obj->strtab + needed->name;
3394 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
3395
3396 fmt = is_lib ? fmt1 : fmt2;
3397 while ((c = *fmt++) != '\0') {
3398 switch (c) {
3399 default:
abfcd5b1 3400 rtld_putchar(c);
984263bc
MD
3401 continue;
3402 case '\\':
3403 switch (c = *fmt) {
3404 case '\0':
3405 continue;
3406 case 'n':
abfcd5b1 3407 rtld_putchar('\n');
984263bc
MD
3408 break;
3409 case 't':
abfcd5b1 3410 rtld_putchar('\t');
984263bc
MD
3411 break;
3412 }
3413 break;
3414 case '%':
3415 switch (c = *fmt) {
3416 case '\0':
3417 continue;
3418 case '%':
3419 default:
abfcd5b1 3420 rtld_putchar(c);
984263bc
MD
3421 break;
3422 case 'A':
abfcd5b1 3423 rtld_putstr(main_local);
984263bc
MD
3424 break;
3425 case 'a':
abfcd5b1 3426 rtld_putstr(obj_main->path);
984263bc
MD
3427 break;
3428 case 'o':
abfcd5b1 3429 rtld_putstr(name);
984263bc 3430 break;
984263bc 3431 case 'p':
abfcd5b1 3432 rtld_putstr(path);
984263bc
MD
3433 break;
3434 case 'x':
abfcd5b1
JM
3435 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
3436 0);
984263bc
MD
3437 break;
3438 }
3439 break;
3440 }
3441 ++fmt;
3442 }
3443 }
3444 }
3445}
3446
3447/*
3448 * Unload a dlopened object and its dependencies from memory and from
3449 * our data structures. It is assumed that the DAG rooted in the
3450 * object has already been unreferenced, and that the object has a
3451 * reference count of 0.
3452 */
3453static void
3454unload_object(Obj_Entry *root)
3455{
3456 Obj_Entry *obj;
3457 Obj_Entry **linkp;
3458
3459 assert(root->refcount == 0);
3460
3461 /*
3462 * Pass over the DAG removing unreferenced objects from
3463 * appropriate lists.
fcf53d9b 3464 */
984263bc
MD
3465 unlink_object(root);
3466
3467 /* Unmap all objects that are no longer referenced. */
3468 linkp = &obj_list->next;
3469 while ((obj = *linkp) != NULL) {
3470 if (obj->refcount == 0) {
fcf53d9b
JM
3471 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
3472 obj->path);
984263bc 3473 dbg("unloading \"%s\"", obj->path);
35b2b265 3474 unload_filtees(root);
984263bc
MD
3475 munmap(obj->mapbase, obj->mapsize);
3476 linkmap_delete(obj);
3477 *linkp = obj->next;
3478 obj_count--;
3479 obj_free(obj);
3480 } else
3481 linkp = &obj->next;
3482 }
3483 obj_tail = linkp;
3484}
3485
3486static void
3487unlink_object(Obj_Entry *root)
3488{
984263bc
MD
3489 Objlist_Entry *elm;
3490
3491 if (root->refcount == 0) {
3492 /* Remove the object from the RTLD_GLOBAL list. */
3493 objlist_remove(&list_global, root);
3494
3495 /* Remove the object from all objects' DAG lists. */
fcf53d9b 3496 STAILQ_FOREACH(elm, &root->dagmembers, link) {
984263bc 3497 objlist_remove(&elm->obj->dldags, root);
fcf53d9b
JM
3498 if (elm->obj != root)
3499 unlink_object(elm->obj);
3500 }
984263bc 3501 }
fcf53d9b 3502}
984263bc 3503
fcf53d9b
JM
3504static void
3505ref_dag(Obj_Entry *root)
3506{
3507 Objlist_Entry *elm;
3508
3509 assert(root->dag_inited);
3510 STAILQ_FOREACH(elm, &root->dagmembers, link)
3511 elm->obj->refcount++;
984263bc
MD
3512}
3513
3514static void
3515unref_dag(Obj_Entry *root)
3516{
fcf53d9b 3517 Objlist_Entry *elm;
984263bc 3518
fcf53d9b
JM
3519 assert(root->dag_inited);
3520 STAILQ_FOREACH(elm, &root->dagmembers, link)
3521 elm->obj->refcount--;
984263bc 3522}
55b88cae
DX
3523
3524/*
3525 * Common code for MD __tls_get_addr().
3526 */
3527void *
fcf53d9b 3528tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset)
55b88cae
DX
3529{
3530 Elf_Addr* dtv = *dtvp;
fcf53d9b 3531 RtldLockState lockstate;
55b88cae
DX
3532
3533 /* Check dtv generation in case new modules have arrived */
3534 if (dtv[0] != tls_dtv_generation) {
3535 Elf_Addr* newdtv;
3536 int to_copy;
3537
fcf53d9b 3538 wlock_acquire(rtld_bind_lock, &lockstate);
55b88cae
DX
3539 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
3540 to_copy = dtv[1];
3541 if (to_copy > tls_max_index)
3542 to_copy = tls_max_index;
3543 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
3544 newdtv[0] = tls_dtv_generation;
3545 newdtv[1] = tls_max_index;
3546 free(dtv);
fcf53d9b 3547 lock_release(rtld_bind_lock, &lockstate);
0c151ba0 3548 dtv = *dtvp = newdtv;
55b88cae
DX
3549 }
3550
3551 /* Dynamically allocate module TLS if necessary */
3552 if (!dtv[index + 1]) {
fcf53d9b
JM
3553 /* Signal safe, wlock will block out signals. */
3554 wlock_acquire(rtld_bind_lock, &lockstate);
3555 if (!dtv[index + 1])
55b88cae 3556 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
fcf53d9b 3557 lock_release(rtld_bind_lock, &lockstate);
55b88cae 3558 }
55b88cae
DX
3559 return (void*) (dtv[index + 1] + offset);
3560}
3561
9e2ee207 3562#if defined(RTLD_STATIC_TLS_VARIANT_II)
55b88cae
DX
3563
3564/*
bc633d63
MD
3565 * Allocate the static TLS area. Return a pointer to the TCB. The
3566 * static area is based on negative offsets relative to the tcb.
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3567 *
3568 * The TCB contains an errno pointer for the system call layer, but because
3569 * we are the RTLD we really have no idea how the caller was compiled so
3570 * the information has to be passed in. errno can either be:
3571 *
3572 * type 0 errno is a simple non-TLS global pointer.
3573 * (special case for e.g. libc_rtld)
3574 * type 1 errno accessed by GOT entry (dynamically linked programs)
3575 * type 2 errno accessed by %gs:OFFSET (statically linked programs)
55b88cae 3576 */
bc633d63 3577struct tls_tcb *
a1eee96a 3578allocate_tls(Obj_Entry *objs)
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3579{
3580 Obj_Entry *obj;
bc633d63 3581 size_t data_size;
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3582 size_t dtv_size;
3583 struct tls_tcb *tcb;
a1eee96a 3584 Elf_Addr *dtv;
bc633d63 3585 Elf_Addr addr;
55b88cae 3586
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MD
3587 /*
3588 * Allocate the new TCB. static TLS storage is placed just before the
3589 * TCB to support the %gs:OFFSET (negative offset) model.
3590 */
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3591 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
3592 ~RTLD_STATIC_TLS_ALIGN_MASK;
f20fd431 3593 tcb = malloc(data_size + sizeof(*tcb));
bc633d63 3594 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */
55b88cae 3595
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MD
3596 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr);
3597 dtv = malloc(dtv_size);
3598 bzero(dtv, dtv_size);
55b88cae 3599
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3600#ifdef RTLD_TCB_HAS_SELF_POINTER
3601 tcb->tcb_self = tcb;
3602#endif
3603 tcb->tcb_dtv = dtv;
3604 tcb->tcb_pthread = NULL;
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3605
3606 dtv[0] = tls_dtv_generation;
3607 dtv[1] = tls_max_index;
3608
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3609 for (obj = objs; obj; obj = obj->next) {
3610 if (obj->tlsoffset) {
3611 addr = (Elf_Addr)tcb - obj->tlsoffset;
3612 memset((void *)(addr + obj->tlsinitsize),
3613 0, obj->tlssize - obj->tlsinitsize);
3614 if (obj->tlsinit)
3615 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
3616 dtv[obj->tlsindex + 1] = addr;
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3617 }
3618 }
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