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
140
141
142
143
144
145
146
147
|
/* Copyright (C) 1991, 92, 94, 95, 96, 97 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <stddef.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
#include <signal.h>
#include <sys/types.h>
#include <errno.h>
#ifndef HAVE_GNU_LD
#define __environ environ
#endif
#define SHELL_PATH "/bin/sh" /* Path of the shell. */
#define SHELL_NAME "sh" /* Name to give it. */
/* Execute LINE as a shell command, returning its status. */
int
__libc_system (const char *line)
{
int status, save;
pid_t pid;
struct sigaction sa, intr, quit;
#ifndef WAITPID_CANNOT_BLOCK_SIGCHLD
sigset_t block, omask;
#endif
if (line == NULL)
/* This signals that we have a command processor available. */
return 1;
sa.sa_handler = SIG_IGN;
sa.sa_flags = 0;
__sigemptyset (&sa.sa_mask);
if (__sigaction (SIGINT, &sa, &intr) < 0)
return -1;
if (__sigaction (SIGQUIT, &sa, &quit) < 0)
{
save = errno;
(void) __sigaction (SIGINT, &intr, (struct sigaction *) NULL);
__set_errno (save);
return -1;
}
#ifndef WAITPID_CANNOT_BLOCK_SIGCHLD
/* SCO 3.2v4 has a bug where `waitpid' will never return if SIGCHLD is
blocked. This makes it impossible for `system' to be implemented in
compliance with POSIX.2-1992. They have acknowledged that this is a bug
but I have not seen nor heard of any forthcoming fix. */
__sigemptyset (&block);
__sigaddset (&block, SIGCHLD);
save = errno;
if (__sigprocmask (SIG_BLOCK, &block, &omask) < 0)
{
if (errno == ENOSYS)
__set_errno (save);
else
{
save = errno;
(void) __sigaction (SIGINT, &intr, (struct sigaction *) NULL);
(void) __sigaction (SIGQUIT, &quit, (struct sigaction *) NULL);
__set_errno (save);
return -1;
}
}
#define UNBLOCK __sigprocmask (SIG_SETMASK, &omask, (sigset_t *) NULL)
#else
#define UNBLOCK 0
#endif
pid = __vfork ();
if (pid == (pid_t) 0)
{
/* Child side. */
const char *new_argv[4];
new_argv[0] = SHELL_NAME;
new_argv[1] = "-c";
new_argv[2] = line;
new_argv[3] = NULL;
/* Restore the signals. */
(void) __sigaction (SIGINT, &intr, (struct sigaction *) NULL);
(void) __sigaction (SIGQUIT, &quit, (struct sigaction *) NULL);
(void) UNBLOCK;
/* Exec the shell. */
(void) __execve (SHELL_PATH, (char *const *) new_argv, __environ);
_exit (127);
}
else if (pid < (pid_t) 0)
/* The fork failed. */
status = -1;
else
/* Parent side. */
#ifdef NO_WAITPID
{
pid_t child;
do
{
child = __wait (&status);
if (child <= -1)
{
status = -1;
break;
}
} while (child != pid);
}
#else
if (__waitpid (pid, &status, 0) != pid)
status = -1;
#endif
save = errno;
if ((__sigaction (SIGINT, &intr, (struct sigaction *) NULL) |
__sigaction (SIGQUIT, &quit, (struct sigaction *) NULL) |
UNBLOCK) != 0)
{
if (errno == ENOSYS)
__set_errno (save);
else
return -1;
}
return status;
}
weak_alias (__libc_system, system)
|
