1 /* Support for dynamic linking code in static libc.
2 Copyright (C) 1996-2008,2009,2010 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
20 /* This file defines some things that for the dynamic linker are defined in
21 rtld.c and dl-sysdep.c in ways appropriate to bootstrap dynamic linking. */
28 #include <dl-machine.h>
29 #include <bits/libc-lock.h>
31 #include <dl-librecon.h>
32 #include <dl-procinfo.h>
33 #include <unsecvars.h>
34 #include <hp-timing.h>
35 #include <stackinfo.h>
37 extern char *__progname
;
38 char **_dl_argv
= &__progname
; /* This is checked for some error messages. */
40 /* Name of the architecture. */
41 const char *_dl_platform
;
42 size_t _dl_platformlen
;
46 ElfW(Addr
) _dl_use_load_bias
= -2;
49 /* If nonzero print warnings about problematic situations. */
52 /* We never do profiling. */
53 const char *_dl_profile
;
54 const char *_dl_profile_output
;
56 /* Names of shared object for which the RUNPATHs and RPATHs should be
58 const char *_dl_inhibit_rpath
;
60 /* The map for the object we will profile. */
61 struct link_map
*_dl_profile_map
;
63 /* This is the address of the last stack address ever used. */
64 void *__libc_stack_end
;
66 /* Path where the binary is found. */
67 const char *_dl_origin_path
;
69 /* Nonzero if runtime lookup should not update the .got/.plt. */
72 /* Namespace information. */
73 struct link_namespaces _dl_ns
[DL_NNS
];
76 /* Incremented whenever something may have been added to dl_loaded. */
77 unsigned long long _dl_load_adds
;
79 /* Fake scope. In dynamically linked binaries this is the scope of the
80 main application but here we don't have something like this. So
81 create a fake scope containing nothing. */
82 struct r_scope_elem _dl_initial_searchlist
;
84 #ifndef HAVE_INLINED_SYSCALLS
85 /* Nonzero during startup. */
86 int _dl_starting_up
= 1;
89 /* Random data provided by the kernel. */
92 /* Get architecture specific initializer. */
93 #include <dl-procinfo.c>
95 /* We expect less than a second for relocation. */
96 #ifdef HP_SMALL_TIMING_AVAIL
97 # undef HP_TIMING_AVAIL
98 # define HP_TIMING_AVAIL HP_SMALL_TIMING_AVAIL
101 /* Initial value of the CPU clock. */
102 #ifndef HP_TIMING_NONAVAIL
103 hp_timing_t _dl_cpuclock_offset
;
106 void (*_dl_init_static_tls
) (struct link_map
*) = &_dl_nothread_init_static_tls
;
110 unsigned int _dl_osversion
;
112 /* All known directories in sorted order. */
113 struct r_search_path_elem
*_dl_all_dirs
;
115 /* All directories after startup. */
116 struct r_search_path_elem
*_dl_init_all_dirs
;
118 /* The object to be initialized first. */
119 struct link_map
*_dl_initfirst
;
121 /* Descriptor to write debug messages to. */
122 int _dl_debug_fd
= STDERR_FILENO
;
124 int _dl_correct_cache_id
= _DL_CACHE_DEFAULT_ID
;
126 ElfW(Phdr
) *_dl_phdr
;
128 uint64_t _dl_hwcap
__attribute__ ((nocommon
));
130 /* This is not initialized to HWCAP_IMPORTANT, matching the definition
131 of _dl_important_hwcaps, below, where no hwcap strings are ever
132 used. This mask is still used to mediate the lookups in the cache
133 file. Since there is no way to set this nonzero (we don't grok the
134 LD_HWCAP_MASK environment variable here), there is no real point in
135 setting _dl_hwcap nonzero below, but we do anyway. */
136 uint64_t _dl_hwcap_mask
__attribute__ ((nocommon
));
138 /* Prevailing state of the stack. Generally this includes PF_X, indicating it's
139 * executable but this isn't true for all platforms. */
140 ElfW(Word
) _dl_stack_flags
= DEFAULT_STACK_PERMS
;
142 /* If loading a shared object requires that we make the stack executable
143 when it was not, we do it by calling this function.
144 It returns an errno code or zero on success. */
145 int (*_dl_make_stack_executable_hook
) (void **) internal_function
146 = _dl_make_stack_executable
;
149 /* Function in libpthread to wait for termination of lookups. */
150 void (*_dl_wait_lookup_done
) (void);
152 struct dl_scope_free_list
*_dl_scope_free_list
;
154 #ifdef NEED_DL_SYSINFO
155 /* Needed for improved syscall handling on at least x86/Linux. */
156 uintptr_t _dl_sysinfo
= DL_SYSINFO_DEFAULT
;
158 #if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
159 /* Address of the ELF headers in the vsyscall page. */
160 const ElfW(Ehdr
) *_dl_sysinfo_dso
;
163 /* During the program run we must not modify the global data of
164 loaded shared object simultanously in two threads. Therefore we
165 protect `_dl_open' and `_dl_close' in dl-close.c.
167 This must be a recursive lock since the initializer function of
168 the loaded object might as well require a call to this function.
169 At this time it is not anymore a problem to modify the tables. */
170 __rtld_lock_define_initialized_recursive (, _dl_load_lock
)
171 /* This lock is used to keep __dl_iterate_phdr from inspecting the
172 list of loaded objects while an object is added to or removed from
174 __rtld_lock_define_initialized_recursive (, _dl_load_write_lock
)
177 #ifdef HAVE_AUX_VECTOR
182 _dl_aux_init (ElfW(auxv_t
) *av
)
188 for (; av
->a_type
!= AT_NULL
; ++av
)
192 GLRO(dl_pagesize
) = av
->a_un
.a_val
;
195 GLRO(dl_clktck
) = av
->a_un
.a_val
;
198 GL(dl_phdr
) = (void *) av
->a_un
.a_val
;
201 GL(dl_phnum
) = av
->a_un
.a_val
;
204 GLRO(dl_hwcap
) = (unsigned long int) av
->a_un
.a_val
;
206 #ifdef NEED_DL_SYSINFO
208 GL(dl_sysinfo
) = av
->a_un
.a_val
;
211 #if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
212 case AT_SYSINFO_EHDR
:
213 GL(dl_sysinfo_dso
) = (void *) av
->a_un
.a_val
;
217 uid
^= av
->a_un
.a_val
;
221 uid
^= av
->a_un
.a_val
;
225 gid
^= av
->a_un
.a_val
;
229 gid
^= av
->a_un
.a_val
;
234 __libc_enable_secure
= av
->a_un
.a_val
;
235 __libc_enable_secure_decided
= 1;
238 _dl_random
= (void *) av
->a_un
.a_val
;
240 # ifdef DL_PLATFORM_AUXV
246 __libc_enable_secure
= uid
!= 0 || gid
!= 0;
247 __libc_enable_secure_decided
= 1;
255 _dl_non_dynamic_init (void)
258 HP_TIMING_NOW (_dl_cpuclock_offset
);
261 _dl_pagesize
= __getpagesize ();
263 _dl_verbose
= *(getenv ("LD_WARN") ?: "") == '\0' ? 0 : 1;
265 /* Initialize the data structures for the search paths for shared
267 _dl_init_paths (getenv ("LD_LIBRARY_PATH"));
269 /* Remember the last search directory added at startup. */
270 _dl_init_all_dirs
= GL(dl_all_dirs
);
272 _dl_lazy
= *(getenv ("LD_BIND_NOW") ?: "") == '\0';
274 _dl_bind_not
= *(getenv ("LD_BIND_NOT") ?: "") != '\0';
276 _dl_dynamic_weak
= *(getenv ("LD_DYNAMIC_WEAK") ?: "") == '\0';
278 _dl_profile_output
= getenv ("LD_PROFILE_OUTPUT");
279 if (_dl_profile_output
== NULL
|| _dl_profile_output
[0] == '\0')
281 = &"/var/tmp\0/var/profile"[__libc_enable_secure
? 9 : 0];
283 if (__libc_enable_secure
)
285 static const char unsecure_envvars
[] =
287 #ifdef EXTRA_UNSECURE_ENVVARS
288 EXTRA_UNSECURE_ENVVARS
291 const char *cp
= unsecure_envvars
;
293 while (cp
< unsecure_envvars
+ sizeof (unsecure_envvars
))
296 cp
= (const char *) __rawmemchr (cp
, '\0') + 1;
299 if (__access ("/etc/suid-debug", F_OK
) != 0)
300 __unsetenv ("MALLOC_CHECK_");
303 #ifdef DL_PLATFORM_INIT
307 #ifdef DL_OSVERSION_INIT
311 /* Now determine the length of the platform string. */
312 if (_dl_platform
!= NULL
)
313 _dl_platformlen
= strlen (_dl_platform
);
315 /* Scan for a program header telling us the stack is nonexecutable. */
316 if (_dl_phdr
!= NULL
)
317 for (uint_fast16_t i
= 0; i
< _dl_phnum
; ++i
)
318 if (_dl_phdr
[i
].p_type
== PT_GNU_STACK
)
320 _dl_stack_flags
= _dl_phdr
[i
].p_flags
;
326 const struct r_strlenpair
*
328 _dl_important_hwcaps (const char *platform
, size_t platform_len
, size_t *sz
,
329 size_t *max_capstrlen
)
331 static struct r_strlenpair result
;
334 result
.str
= buf
; /* Does not really matter. */
342 #ifdef DL_SYSINFO_IMPLEMENTATION
343 DL_SYSINFO_IMPLEMENTATION