1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
/* $NetBSD: initfini.c,v 1.14 2017/06/17 15:26:44 joerg Exp $ */
/*-
* Copyright (c) 2007 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Andrew Doran.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: initfini.c,v 1.14 2017/06/17 15:26:44 joerg Exp $");
#ifdef _LIBC
#include "namespace.h"
#endif
#include <sys/param.h>
#include <sys/exec.h>
#include <sys/tls.h>
#include <stdbool.h>
void _libc_init(void) __attribute__((__constructor__, __used__));
void __guard_setup(void);
void __libc_thr_init(void);
void __libc_atomic_init(void);
void __libc_atexit_init(void);
void __libc_env_init(void);
#if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II)
__dso_hidden void __libc_static_tls_setup(void);
#endif
#ifdef __weak_alias
__weak_alias(_dlauxinfo,___dlauxinfo)
static void *__libc_dlauxinfo;
void *___dlauxinfo(void) __pure;
__weakref_visible void * real_dlauxinfo(void) __weak_reference(_dlauxinfo);
void *
___dlauxinfo(void)
{
return __libc_dlauxinfo;
}
#endif
static bool libc_initialised;
void _libc_init(void);
/*
* Declare as common symbol to allow new libc with older binaries to
* not trigger an undefined reference.
*/
struct ps_strings *__ps_strings;
/*
* _libc_init is called twice. One call comes explicitly from crt0.o
* (for newer versions) and the other is via global constructor handling.
*
* In static binaries the explicit call is first; in dynamically linked
* binaries the global constructors of libc are called from ld.elf_so
* before crt0.o is reached.
*
* Note that __ps_strings is set by crt0.o. So in the dynamic case, it
* hasn't been set yet when we get here, and __libc_dlauxinfo is not
* (ever) assigned. But this is ok because __libc_dlauxinfo is only
* used in static binaries, because it's there to substitute for the
* dynamic linker. In static binaries __ps_strings will have been set
* up when we get here and we get a valid __libc_dlauxinfo.
*
* This code causes problems for Emacs because Emacs's undump
* mechanism saves the __ps_strings value from the startup execution;
* then running the resulting binary it gets here before crt0 has
* assigned the current execution's value to __ps_strings, and in an
* environment with ASLR this can cause the assignment of
* __libc_dlauxinfo to receive SIGSEGV.
*/
void __section(".text.startup")
_libc_init(void)
{
if (libc_initialised)
return;
libc_initialised = 1;
/* Only initialize _dlauxinfo for static binaries. */
if (__ps_strings != NULL && real_dlauxinfo == ___dlauxinfo)
__libc_dlauxinfo = __ps_strings->ps_argvstr +
__ps_strings->ps_nargvstr + __ps_strings->ps_nenvstr + 2;
/* For -fstack-protector */
__guard_setup();
/* Atomic operations */
__libc_atomic_init();
#if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II)
/* Initialize TLS for statically linked programs. */
__libc_static_tls_setup();
#endif
/* Threads */
__libc_thr_init();
/* Initialize the atexit mutexes */
__libc_atexit_init();
/* Initialize environment memory RB tree. */
__libc_env_init();
}
|