1 /* Support for dynamic linking code in static libc.
2 Copyright (C) 1996-2002, 2003, 2004 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 <unsecvars.h>
33 #include <hp-timing.h>
35 extern char *__progname;
36 char **_dl_argv = &__progname; /* This is checked for some error messages. */
38 /* Name of the architecture. */
39 const char *_dl_platform;
40 size_t _dl_platformlen;
44 ElfW(Addr) _dl_use_load_bias = -2;
47 /* If nonzero print warnings about problematic situations. */
50 /* We never do profiling. */
51 const char *_dl_profile;
53 /* Names of shared object for which the RUNPATHs and RPATHs should be
55 const char *_dl_inhibit_rpath;
57 /* The map for the object we will profile. */
58 struct link_map *_dl_profile_map;
60 /* This is the address of the last stack address ever used. */
61 void *__libc_stack_end;
63 /* Path where the binary is found. */
64 const char *_dl_origin_path;
66 /* Nonzero if runtime lookup should not update the .got/.plt. */
69 /* Initially empty list of loaded objects. */
70 struct link_map *_dl_loaded;
71 /* Number of object in the _dl_loaded list. */
72 unsigned int _dl_nloaded;
74 /* Incremented whenever something may have been added to dl_loaded. */
75 unsigned long long _dl_load_adds;
77 /* Fake scope. In dynamically linked binaries this is the scope of the
78 main application but here we don't have something like this. So
79 create a fake scope containing nothing. */
80 struct r_scope_elem _dl_initial_searchlist;
81 /* Variable which can be used in lookup to process the global scope. */
82 struct r_scope_elem *_dl_global_scope[2] = { &_dl_initial_searchlist, NULL };
83 /* This is a global pointer to this structure which is public. It is
84 used by dlopen/dlclose to add and remove objects from what is regarded
85 to be the global scope. */
86 struct r_scope_elem *_dl_main_searchlist = &_dl_initial_searchlist;
88 /* Nonzero during startup. */
89 int _dl_starting_up = 1;
91 /* Get architecture specific initializer. */
92 #include <dl-procinfo.c>
94 /* We expect less than a second for relocation. */
95 #ifdef HP_SMALL_TIMING_AVAIL
96 # undef HP_TIMING_AVAIL
97 # define HP_TIMING_AVAIL HP_SMALL_TIMING_AVAIL
100 /* Initial value of the CPU clock. */
101 #ifndef HP_TIMING_NONAVAIL
102 hp_timing_t _dl_cpuclock_offset;
106 void (*_dl_init_static_tls) (struct link_map *) = &_dl_nothread_init_static_tls;
109 /* This is zero at program start to signal that the global scope map is
110 allocated by rtld. Later it keeps the size of the map. It might be
111 reset if in _dl_close if the last global object is removed. */
112 size_t _dl_global_scope_alloc;
116 unsigned int _dl_osversion;
118 /* All known directories in sorted order. */
119 struct r_search_path_elem *_dl_all_dirs;
121 /* All directories after startup. */
122 struct r_search_path_elem *_dl_init_all_dirs;
124 /* The object to be initialized first. */
125 struct link_map *_dl_initfirst;
127 /* Descriptor to write debug messages to. */
128 int _dl_debug_fd = STDERR_FILENO;
130 int _dl_correct_cache_id = _DL_CACHE_DEFAULT_ID;
132 ElfW(Phdr) *_dl_phdr;
134 unsigned long int _dl_hwcap __attribute__ ((nocommon));
136 /* Prevailing state of the stack, PF_X indicating it's executable. */
137 ElfW(Word) _dl_stack_flags = PF_R|PF_W|PF_X;
139 /* If loading a shared object requires that we make the stack executable
140 when it was not, we do it by calling this function.
141 It returns an errno code or zero on success. */
142 int (*_dl_make_stack_executable_hook) (void **) internal_function
143 = _dl_make_stack_executable;
146 #ifdef NEED_DL_SYSINFO
147 /* Needed for improved syscall handling on at least x86/Linux. */
148 uintptr_t _dl_sysinfo = DL_SYSINFO_DEFAULT;
149 /* Address of the ELF headers in the vsyscall page. */
150 const ElfW(Ehdr) *_dl_sysinfo_dso;
153 /* During the program run we must not modify the global data of
154 loaded shared object simultanously in two threads. Therefore we
155 protect `_dl_open' and `_dl_close' in dl-close.c.
157 This must be a recursive lock since the initializer function of
158 the loaded object might as well require a call to this function.
159 At this time it is not anymore a problem to modify the tables. */
160 __rtld_lock_define_initialized_recursive (, _dl_load_lock)
163 #ifdef HAVE_AUX_VECTOR
168 _dl_aux_init (ElfW(auxv_t) *av)
174 for (; av->a_type != AT_NULL; ++av)
178 GL(dl_pagesize) = av->a_un.a_val;
181 GL(dl_clktck) = av->a_un.a_val;
184 GL(dl_phdr) = av->a_un.a_ptr;
187 GL(dl_phnum) = av->a_un.a_val;
190 GL(dl_hwcap) = av->a_un.a_val;
192 #ifdef NEED_DL_SYSINFO
194 GL(dl_sysinfo) = av->a_un.a_val;
198 uid ^= av->a_un.a_val;
202 uid ^= av->a_un.a_val;
206 gid ^= av->a_un.a_val;
210 gid ^= av->a_un.a_val;
215 __libc_enable_secure = av->a_un.a_val;
216 __libc_enable_secure_decided = 1;
221 __libc_enable_secure = uid != 0 || gid != 0;
222 __libc_enable_secure_decided = 1;
230 _dl_non_dynamic_init (void)
233 HP_TIMING_NOW (_dl_cpuclock_offset);
236 _dl_pagesize = __getpagesize ();
238 _dl_verbose = *(getenv ("LD_WARN") ?: "") == '\0' ? 0 : 1;
240 /* Initialize the data structures for the search paths for shared
242 _dl_init_paths (getenv ("LD_LIBRARY_PATH"));
244 _dl_lazy = *(getenv ("LD_BIND_NOW") ?: "") == '\0';
246 _dl_bind_not = *(getenv ("LD_BIND_NOT") ?: "") != '\0';
248 _dl_dynamic_weak = *(getenv ("LD_DYNAMIC_WEAK") ?: "") == '\0';
250 if (__libc_enable_secure)
252 static const char *unsecure_envvars[] =
255 #ifdef EXTRA_UNSECURE_ENVVARS
256 EXTRA_UNSECURE_ENVVARS
262 cnt < sizeof (unsecure_envvars) / sizeof (unsecure_envvars[0]);
264 unsetenv (unsecure_envvars[cnt]);
266 if (__access ("/etc/suid-debug", F_OK) != 0)
267 unsetenv ("MALLOC_CHECK_");
270 #ifdef DL_PLATFORM_INIT
274 #ifdef DL_OSVERSION_INIT
278 /* Now determine the length of the platform string. */
279 if (_dl_platform != NULL)
280 _dl_platformlen = strlen (_dl_platform);
282 /* Scan for a program header telling us the stack is nonexecutable. */
283 if (_dl_phdr != NULL)
284 for (uint_fast16_t i = 0; i < _dl_phnum; ++i)
285 if (_dl_phdr[i].p_type == PT_GNU_STACK)
287 _dl_stack_flags = _dl_phdr[i].p_flags;
293 const struct r_strlenpair *
295 _dl_important_hwcaps (const char *platform, size_t platform_len, size_t *sz,
296 size_t *max_capstrlen)
298 static struct r_strlenpair result;
301 result.str = buf; /* Does not really matter. */
309 #ifdef DL_SYSINFO_IMPLEMENTATION
310 DL_SYSINFO_IMPLEMENTATION