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
|
/*
*
* Copyright 2008 Javier Merino <cibervicho@gmail.com>
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* This program 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 General
* Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
#include <sys/types.h>
int main(int argc, char **argv) {
ssize_t r;
int fds[2];
int child_status;
pid_t child_pid;
char buf[BUFSIZ];
if (argc < 2) {
/* Noop */
return EXIT_SUCCESS;
}
r = read(0, buf, BUFSIZ*sizeof(char));
if (r == 0)
return EXIT_SUCCESS;
else if (r == -1) {
perror("read");
return EXIT_FAILURE;
}
if (pipe(fds)) {
perror("pipe");
return EXIT_FAILURE;
}
child_pid = fork();
if (!child_pid) {
/* child process: rebind stdin and exec the subcommand */
close(fds[1]);
if (dup2(fds[0], 0)) {
perror("dup2");
return EXIT_FAILURE;
}
execvp(argv[1], &argv[1]);
perror(argv[1]);
close(fds[0]);
return EXIT_FAILURE;
} else if (child_pid == -1) {
perror("fork");
return EXIT_FAILURE;
}
/* Parent: write in fds[1] our stdin */
close(fds[0]);
do {
if (write(fds[1], buf, r*sizeof(char)) == -1) {
fprintf(stderr, "Write error to %s\n", argv[1]);
exit(EXIT_FAILURE);
}
r = read(0, buf, BUFSIZ*sizeof(char));
} while (r > 0);
if (r == -1) {
perror("read");
exit(EXIT_FAILURE);
}
close(fds[1]);
if (waitpid(child_pid, &child_status, 0) != child_pid) {
perror("waitpid");
return EXIT_FAILURE;
}
if (WIFEXITED(child_status)) {
return (WEXITSTATUS(child_status));
} else if (WIFSIGNALED(child_status)) {
raise(WTERMSIG(child_status));
return EXIT_FAILURE;
}
return EXIT_FAILURE;
}
|
