1 /* Operating system support for run-time dynamic linker. Generic Unix version.
2 Copyright (C) 1995-2013 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, see
17 <http://www.gnu.org/licenses/>. */
19 /* We conditionalize the whole of this file rather than simply eliding it
20 from the static build, because other sysdeps/ versions of this file
21 might define things needed by a static build. */
33 #include <sys/types.h>
38 #include <fpu_control.h>
41 #include <dl-machine.h>
42 #include <dl-procinfo.h>
43 #include <dl-osinfo.h>
44 #include <hp-timing.h>
47 extern char **_environ attribute_hidden
;
48 extern char _end
[] attribute_hidden
;
50 /* Protect SUID program against misuse of file descriptors. */
51 extern void __libc_check_standard_fds (void);
53 #ifdef NEED_DL_BASE_ADDR
54 ElfW(Addr
) _dl_base_addr
;
56 int __libc_enable_secure attribute_relro
= 0;
57 INTVARDEF(__libc_enable_secure
)
58 int __libc_multiple_libcs
= 0; /* Defining this here avoids the inclusion
60 /* This variable contains the lowest stack address ever used. */
61 void *__libc_stack_end attribute_relro
= NULL
;
62 rtld_hidden_data_def(__libc_stack_end
)
63 void *_dl_random attribute_relro
= NULL
;
65 #ifndef DL_FIND_ARG_COMPONENTS
66 # define DL_FIND_ARG_COMPONENTS(cookie, argc, argv, envp, auxp) \
69 (argc) = *(long int *) cookie; \
70 (argv) = (char **) ((long int *) cookie + 1); \
71 (envp) = (argv) + (argc) + 1; \
72 for (_tmp = (void **) (envp); *_tmp; ++_tmp) \
74 (auxp) = (void *) ++_tmp; \
79 # define DL_STACK_END(cookie) ((void *) (cookie))
83 _dl_sysdep_start (void **start_argptr
,
84 void (*dl_main
) (const ElfW(Phdr
) *phdr
, ElfW(Word
) phnum
,
85 ElfW(Addr
) *user_entry
, ElfW(auxv_t
) *auxv
))
87 const ElfW(Phdr
) *phdr
= NULL
;
89 ElfW(Addr
) user_entry
;
91 #ifdef HAVE_AUX_SECURE
92 # define set_seen(tag) (tag) /* Evaluate for the side effects. */
93 # define set_seen_secure() ((void) 0)
97 unsigned int seen
= 0;
98 # define set_seen_secure() (seen = -1)
100 # define set_seen(tag) (tag) /* Evaluate for the side effects. */
102 # define M(type) (1 << (type))
103 # define set_seen(tag) seen |= M ((tag)->a_type)
106 #ifdef NEED_DL_SYSINFO
107 uintptr_t new_sysinfo
= 0;
110 __libc_stack_end
= DL_STACK_END (start_argptr
);
111 DL_FIND_ARG_COMPONENTS (start_argptr
, _dl_argc
, INTUSE(_dl_argv
), _environ
,
114 user_entry
= (ElfW(Addr
)) ENTRY_POINT
;
115 GLRO(dl_platform
) = NULL
; /* Default to nothing known about the platform. */
117 for (av
= GLRO(dl_auxv
); av
->a_type
!= AT_NULL
; set_seen (av
++))
121 phdr
= (void *) av
->a_un
.a_val
;
124 phnum
= av
->a_un
.a_val
;
127 GLRO(dl_pagesize
) = av
->a_un
.a_val
;
130 user_entry
= av
->a_un
.a_val
;
132 #ifdef NEED_DL_BASE_ADDR
134 _dl_base_addr
= av
->a_un
.a_val
;
137 #ifndef HAVE_AUX_SECURE
140 uid
^= av
->a_un
.a_val
;
144 gid
^= av
->a_un
.a_val
;
148 #ifndef HAVE_AUX_SECURE
151 INTUSE(__libc_enable_secure
) = av
->a_un
.a_val
;
154 GLRO(dl_platform
) = (void *) av
->a_un
.a_val
;
157 GLRO(dl_hwcap
) = (unsigned long int) av
->a_un
.a_val
;
160 GLRO(dl_clktck
) = av
->a_un
.a_val
;
163 GLRO(dl_fpu_control
) = av
->a_un
.a_val
;
165 #ifdef NEED_DL_SYSINFO
167 new_sysinfo
= av
->a_un
.a_val
;
170 #ifdef NEED_DL_SYSINFO_DSO
171 case AT_SYSINFO_EHDR
:
172 GLRO(dl_sysinfo_dso
) = (void *) av
->a_un
.a_val
;
176 _dl_random
= (void *) av
->a_un
.a_val
;
178 #ifdef DL_PLATFORM_AUXV
183 #ifndef HAVE_AUX_SECURE
186 /* Fill in the values we have not gotten from the kernel through the
188 # ifndef HAVE_AUX_XID
189 # define SEE(UID, var, uid) \
190 if ((seen & M (AT_##UID)) == 0) var ^= __get##uid ()
192 SEE (EUID
, uid
, euid
);
194 SEE (EGID
, gid
, egid
);
197 /* If one of the two pairs of IDs does not match this is a setuid
199 INTUSE(__libc_enable_secure
) = uid
| gid
;
203 #ifndef HAVE_AUX_PAGESIZE
204 if (GLRO(dl_pagesize
) == 0)
205 GLRO(dl_pagesize
) = __getpagesize ();
208 #ifdef NEED_DL_SYSINFO
209 if (new_sysinfo
!= 0)
211 # ifdef NEED_DL_SYSINFO_DSO
212 /* Only set the sysinfo value if we also have the vsyscall DSO. */
213 if (GLRO(dl_sysinfo_dso
) != 0)
215 GLRO(dl_sysinfo
) = new_sysinfo
;
219 #ifdef DL_SYSDEP_INIT
223 #ifdef DL_PLATFORM_INIT
227 /* Determine the length of the platform name. */
228 if (GLRO(dl_platform
) != NULL
)
229 GLRO(dl_platformlen
) = strlen (GLRO(dl_platform
));
231 if (__sbrk (0) == _end
)
232 /* The dynamic linker was run as a program, and so the initial break
233 starts just after our bss, at &_end. The malloc in dl-minimal.c
234 will consume the rest of this page, so tell the kernel to move the
235 break up that far. When the user program examines its break, it
236 will see this new value and not clobber our data. */
237 __sbrk (GLRO(dl_pagesize
)
238 - ((_end
- (char *) 0) & (GLRO(dl_pagesize
) - 1)));
240 /* If this is a SUID program we make sure that FDs 0, 1, and 2 are
241 allocated. If necessary we are doing it ourself. If it is not
242 possible we stop the program. */
243 if (__builtin_expect (INTUSE(__libc_enable_secure
), 0))
244 __libc_check_standard_fds ();
246 (*dl_main
) (phdr
, phnum
, &user_entry
, GLRO(dl_auxv
));
252 _dl_sysdep_start_cleanup (void)
263 /* Terminate string. */
266 /* The following code assumes that the AT_* values are encoded
267 starting from 0 with AT_NULL, 1 for AT_IGNORE, and all other values
268 close by (otherwise the array will be too large). In case we have
269 to support a platform where these requirements are not fulfilled
270 some alternative implementation has to be used. */
271 for (av
= GLRO(dl_auxv
); av
->a_type
!= AT_NULL
; ++av
)
275 const char label
[17];
276 enum { unknown
= 0, dec
, hex
, str
, ignore
} form
: 8;
279 [AT_EXECFD
- 2] = { "EXECFD: ", dec
},
280 [AT_EXECFN
- 2] = { "EXECFN: ", str
},
281 [AT_PHDR
- 2] = { "PHDR: 0x", hex
},
282 [AT_PHENT
- 2] = { "PHENT: ", dec
},
283 [AT_PHNUM
- 2] = { "PHNUM: ", dec
},
284 [AT_PAGESZ
- 2] = { "PAGESZ: ", dec
},
285 [AT_BASE
- 2] = { "BASE: 0x", hex
},
286 [AT_FLAGS
- 2] = { "FLAGS: 0x", hex
},
287 [AT_ENTRY
- 2] = { "ENTRY: 0x", hex
},
288 [AT_NOTELF
- 2] = { "NOTELF: ", hex
},
289 [AT_UID
- 2] = { "UID: ", dec
},
290 [AT_EUID
- 2] = { "EUID: ", dec
},
291 [AT_GID
- 2] = { "GID: ", dec
},
292 [AT_EGID
- 2] = { "EGID: ", dec
},
293 [AT_PLATFORM
- 2] = { "PLATFORM: ", str
},
294 [AT_HWCAP
- 2] = { "HWCAP: ", hex
},
295 [AT_CLKTCK
- 2] = { "CLKTCK: ", dec
},
296 [AT_FPUCW
- 2] = { "FPUCW: ", hex
},
297 [AT_DCACHEBSIZE
- 2] = { "DCACHEBSIZE: 0x", hex
},
298 [AT_ICACHEBSIZE
- 2] = { "ICACHEBSIZE: 0x", hex
},
299 [AT_UCACHEBSIZE
- 2] = { "UCACHEBSIZE: 0x", hex
},
300 [AT_IGNOREPPC
- 2] = { "IGNOREPPC", ignore
},
301 [AT_SECURE
- 2] = { "SECURE: ", dec
},
302 [AT_BASE_PLATFORM
- 2] = { "BASE_PLATFORM:", str
},
303 [AT_SYSINFO
- 2] = { "SYSINFO: 0x", hex
},
304 [AT_SYSINFO_EHDR
- 2] = { "SYSINFO_EHDR: 0x", hex
},
305 [AT_RANDOM
- 2] = { "RANDOM: 0x", hex
},
307 unsigned int idx
= (unsigned int) (av
->a_type
- 2);
309 if ((unsigned int) av
->a_type
< 2u
310 || (idx
< sizeof (auxvars
) / sizeof (auxvars
[0])
311 && auxvars
[idx
].form
== ignore
))
314 assert (AT_NULL
== 0);
315 assert (AT_IGNORE
== 1);
317 if (av
->a_type
== AT_HWCAP
)
319 /* This is handled special. */
320 if (_dl_procinfo (av
->a_un
.a_val
) == 0)
324 if (idx
< sizeof (auxvars
) / sizeof (auxvars
[0])
325 && auxvars
[idx
].form
!= unknown
)
327 const char *val
= (char *) av
->a_un
.a_val
;
329 if (__builtin_expect (auxvars
[idx
].form
, dec
) == dec
)
330 val
= _itoa ((unsigned long int) av
->a_un
.a_val
,
331 buf
+ sizeof buf
- 1, 10, 0);
332 else if (__builtin_expect (auxvars
[idx
].form
, hex
) == hex
)
333 val
= _itoa ((unsigned long int) av
->a_un
.a_val
,
334 buf
+ sizeof buf
- 1, 16, 0);
336 _dl_printf ("AT_%s%s\n", auxvars
[idx
].label
, val
);
341 /* Unknown value: print a generic line. */
343 buf2
[sizeof (buf2
) - 1] = '\0';
344 const char *val2
= _itoa ((unsigned long int) av
->a_un
.a_val
,
345 buf2
+ sizeof buf2
- 1, 16, 0);
346 const char *val
= _itoa ((unsigned long int) av
->a_type
,
347 buf
+ sizeof buf
- 1, 16, 0);
348 _dl_printf ("AT_??? (0x%s): 0x%s\n", val
, val2
);