1 /* Operating system support for run-time dynamic linker. Generic Unix version.
2 Copyright (C) 1995-2012 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_hwcap2
) = (unsigned long int) av
->a_un
.a_val
;
163 GLRO(dl_clktck
) = av
->a_un
.a_val
;
166 GLRO(dl_fpu_control
) = av
->a_un
.a_val
;
168 #ifdef NEED_DL_SYSINFO
170 new_sysinfo
= av
->a_un
.a_val
;
173 #if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
174 case AT_SYSINFO_EHDR
:
175 GLRO(dl_sysinfo_dso
) = (void *) av
->a_un
.a_val
;
179 _dl_random
= (void *) av
->a_un
.a_val
;
181 #ifdef DL_PLATFORM_AUXV
186 #ifndef HAVE_AUX_SECURE
189 /* Fill in the values we have not gotten from the kernel through the
191 # ifndef HAVE_AUX_XID
192 # define SEE(UID, var, uid) \
193 if ((seen & M (AT_##UID)) == 0) var ^= __get##uid ()
195 SEE (EUID
, uid
, euid
);
197 SEE (EGID
, gid
, egid
);
200 /* If one of the two pairs of IDs does not match this is a setuid
202 INTUSE(__libc_enable_secure
) = uid
| gid
;
206 #ifndef HAVE_AUX_PAGESIZE
207 if (GLRO(dl_pagesize
) == 0)
208 GLRO(dl_pagesize
) = __getpagesize ();
211 #if defined NEED_DL_SYSINFO
212 /* Only set the sysinfo value if we also have the vsyscall DSO. */
213 if (GLRO(dl_sysinfo_dso
) != 0 && new_sysinfo
)
214 GLRO(dl_sysinfo
) = new_sysinfo
;
217 #ifdef DL_SYSDEP_INIT
221 #ifdef DL_PLATFORM_INIT
225 /* Determine the length of the platform name. */
226 if (GLRO(dl_platform
) != NULL
)
227 GLRO(dl_platformlen
) = strlen (GLRO(dl_platform
));
229 if (__sbrk (0) == _end
)
230 /* The dynamic linker was run as a program, and so the initial break
231 starts just after our bss, at &_end. The malloc in dl-minimal.c
232 will consume the rest of this page, so tell the kernel to move the
233 break up that far. When the user program examines its break, it
234 will see this new value and not clobber our data. */
235 __sbrk (GLRO(dl_pagesize
)
236 - ((_end
- (char *) 0) & (GLRO(dl_pagesize
) - 1)));
238 /* If this is a SUID program we make sure that FDs 0, 1, and 2 are
239 allocated. If necessary we are doing it ourself. If it is not
240 possible we stop the program. */
241 if (__builtin_expect (INTUSE(__libc_enable_secure
), 0))
242 __libc_check_standard_fds ();
244 (*dl_main
) (phdr
, phnum
, &user_entry
, GLRO(dl_auxv
));
250 _dl_sysdep_start_cleanup (void)
261 /* Terminate string. */
264 /* The following code assumes that the AT_* values are encoded
265 starting from 0 with AT_NULL, 1 for AT_IGNORE, and all other values
266 close by (otherwise the array will be too large). In case we have
267 to support a platform where these requirements are not fulfilled
268 some alternative implementation has to be used. */
269 for (av
= GLRO(dl_auxv
); av
->a_type
!= AT_NULL
; ++av
)
273 const char label
[17];
274 enum { unknown
= 0, dec
, hex
, str
, ignore
} form
: 8;
277 [AT_EXECFD
- 2] = { "EXECFD: ", dec
},
278 [AT_EXECFN
- 2] = { "EXECFN: ", str
},
279 [AT_PHDR
- 2] = { "PHDR: 0x", hex
},
280 [AT_PHENT
- 2] = { "PHENT: ", dec
},
281 [AT_PHNUM
- 2] = { "PHNUM: ", dec
},
282 [AT_PAGESZ
- 2] = { "PAGESZ: ", dec
},
283 [AT_BASE
- 2] = { "BASE: 0x", hex
},
284 [AT_FLAGS
- 2] = { "FLAGS: 0x", hex
},
285 [AT_ENTRY
- 2] = { "ENTRY: 0x", hex
},
286 [AT_NOTELF
- 2] = { "NOTELF: ", hex
},
287 [AT_UID
- 2] = { "UID: ", dec
},
288 [AT_EUID
- 2] = { "EUID: ", dec
},
289 [AT_GID
- 2] = { "GID: ", dec
},
290 [AT_EGID
- 2] = { "EGID: ", dec
},
291 [AT_PLATFORM
- 2] = { "PLATFORM: ", str
},
292 [AT_HWCAP
- 2] = { "HWCAP: ", hex
},
293 [AT_CLKTCK
- 2] = { "CLKTCK: ", dec
},
294 [AT_FPUCW
- 2] = { "FPUCW: ", hex
},
295 [AT_DCACHEBSIZE
- 2] = { "DCACHEBSIZE: 0x", hex
},
296 [AT_ICACHEBSIZE
- 2] = { "ICACHEBSIZE: 0x", hex
},
297 [AT_UCACHEBSIZE
- 2] = { "UCACHEBSIZE: 0x", hex
},
298 [AT_IGNOREPPC
- 2] = { "IGNOREPPC", ignore
},
299 [AT_SECURE
- 2] = { "SECURE: ", dec
},
300 [AT_BASE_PLATFORM
- 2] = { "BASE_PLATFORM:", str
},
301 [AT_SYSINFO
- 2] = { "SYSINFO: 0x", hex
},
302 [AT_SYSINFO_EHDR
- 2] = { "SYSINFO_EHDR: 0x", hex
},
303 [AT_RANDOM
- 2] = { "RANDOM: 0x", hex
},
304 [AT_HWCAP2
- 2] = { "HWCAP2: 0x", hex
},
306 unsigned int idx
= (unsigned int) (av
->a_type
- 2);
308 if ((unsigned int) av
->a_type
< 2u
309 || (idx
< sizeof (auxvars
) / sizeof (auxvars
[0])
310 && auxvars
[idx
].form
== ignore
))
313 assert (AT_NULL
== 0);
314 assert (AT_IGNORE
== 1);
316 if (av
->a_type
== AT_HWCAP
|| av
->a_type
== AT_HWCAP2
)
318 /* These are handled in a special way per platform. */
319 if (_dl_procinfo (av
->a_type
, av
->a_un
.a_val
) == 0)
323 if (idx
< sizeof (auxvars
) / sizeof (auxvars
[0])
324 && auxvars
[idx
].form
!= unknown
)
326 const char *val
= (char *) av
->a_un
.a_val
;
328 if (__builtin_expect (auxvars
[idx
].form
, dec
) == dec
)
329 val
= _itoa ((unsigned long int) av
->a_un
.a_val
,
330 buf
+ sizeof buf
- 1, 10, 0);
331 else if (__builtin_expect (auxvars
[idx
].form
, hex
) == hex
)
332 val
= _itoa ((unsigned long int) av
->a_un
.a_val
,
333 buf
+ sizeof buf
- 1, 16, 0);
335 _dl_printf ("AT_%s%s\n", auxvars
[idx
].label
, val
);
340 /* Unknown value: print a generic line. */
342 buf2
[sizeof (buf2
) - 1] = '\0';
343 const char *val2
= _itoa ((unsigned long int) av
->a_un
.a_val
,
344 buf2
+ sizeof buf2
- 1, 16, 0);
345 const char *val
= _itoa ((unsigned long int) av
->a_type
,
346 buf
+ sizeof buf
- 1, 16, 0);
347 _dl_printf ("AT_??? (0x%s): 0x%s\n", val
, val2
);