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
136
137
138
139
|
/* Copyright (C) 1991, 93, 95, 96, 97, 98 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <bits/libc-lock.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
/* Try to get a machine dependent instruction which will make the
program crash. This is used in case everything else fails. */
#include <abort-instr.h>
#ifndef ABORT_INSTRUCTION
/* No such instruction is available. */
# define ABORT_INSTRUCTION
#endif
#ifdef USE_IN_LIBIO
# include <libio/iolibio.h>
# define fflush(s) _IO_fflush (s)
#endif
/* We must avoid to run in circles. Therefore we remember how far we
already got. */
static int stage;
/* We should be prepared for multiple threads trying to run abort. */
__libc_lock_define_initialized_recursive (static, lock);
/* Cause an abnormal program termination with core-dump. */
void
abort (void)
{
struct sigaction act;
sigset_t sigs;
/* First acquire the lock. */
__libc_lock_lock_recursive (lock);
/* Now it's for sure we are alone. But recursive calls are possible. */
/* Unlock SIGABRT. */
if (stage == 0)
{
++stage;
if (__sigemptyset (&sigs) == 0 &&
__sigaddset (&sigs, SIGABRT) == 0)
__sigprocmask (SIG_UNBLOCK, &sigs, (sigset_t *) NULL);
}
/* Flush all streams. We cannot close them now because the user
might have registered a handler for SIGABRT. */
if (stage == 1)
{
++stage;
fflush (NULL);
}
/* Send signal which possibly calls a user handler. */
if (stage == 2)
{
/* This stage is special: we must allow repeated calls of
`abort' when a user defined handler for SIGABRT is installed.
This is risky since the `raise' implementation might also
fail but I don't see another possibility. */
int save_stage = stage;
stage = 0;
__libc_lock_unlock_recursive (lock);
raise (SIGABRT);
__libc_lock_lock_recursive (lock);
stage = save_stage + 1;
}
/* There was a handler installed. Now remove it. */
if (stage == 3)
{
++stage;
memset (&act, '\0', sizeof (struct sigaction));
act.sa_handler = SIG_DFL;
__sigfillset (&act.sa_mask);
act.sa_flags = 0;
__sigaction (SIGABRT, &act, NULL);
}
/* Now close the streams which also flushes the output the user
defined handler might has produced. */
if (stage == 4)
{
++stage;
__fcloseall ();
}
/* Try again. */
if (stage == 5)
{
++stage;
raise (SIGABRT);
}
/* Now try to abort using the system specific command. */
if (stage == 6)
{
++stage;
ABORT_INSTRUCTION;
}
/* If we can't signal ourselves and the abort instruction failed, exit. */
if (stage == 7)
{
++stage;
_exit (127);
}
/* If even this fails try to use the provided instruction to crash
or otherwise make sure we never return. */
while (1)
/* Try for ever and ever. */
ABORT_INSTRUCTION;
}
|
