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DEFINITIONS
This source file includes following definitions.
- system
1 /*
2 * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
3 * The President and Fellows of Harvard College.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #include <errno.h>
31 #include <stdlib.h>
32 #include <unistd.h>
33 #include <string.h>
34
35 /*
36 * system(): ANSI C
37 *
38 * Run a command.
39 */
40
41 #define MAXCMDSIZE 2048
42 #define MAXARGS 128
43
44 int
45 system(const char *cmd)
46 {
47 /*
48 * Ordinarily, you call the shell to process the command.
49 * But we don't know that the shell can do that. So, do it
50 * ourselves.
51 */
52
53 char tmp[MAXCMDSIZE];
54 char *argv[MAXARGS+1];
55 int nargs=0;
56 char *s;
57 int pid, status;
58
59 if (strlen(cmd) >= sizeof(tmp)) {
60 errno = E2BIG;
61 return -1;
62 }
63 strcpy(tmp, cmd);
64
65 for (s = strtok(tmp, " \t"); s; s = strtok(NULL, " \t")) {
66 if (nargs < MAXARGS) {
67 argv[nargs++] = s;
68 }
69 else {
70 errno = E2BIG;
71 return 1;
72 }
73 }
74
75 argv[nargs] = NULL;
76
77 pid = fork();
78 switch (pid) {
79 case -1:
80 return -1;
81 case 0:
82 /* child */
83 execv(argv[0], argv);
84 /* exec only returns if it fails */
85 _exit(255);
86 default:
87 /* parent */
88 waitpid(pid, &status, 0);
89 return status;
90 }
91 }