2015-12-23 00:50:04 +00:00

92 lines
2.5 KiB
C

/*
* Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
* The President and Fellows of Harvard College.
*
* 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.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY 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 UNIVERSITY 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 <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
/*
* system(): ANSI C
*
* Run a command.
*/
#define MAXCMDSIZE 2048
#define MAXARGS 128
int
system(const char *cmd)
{
/*
* Ordinarily, you call the shell to process the command.
* But we don't know that the shell can do that. So, do it
* ourselves.
*/
char tmp[MAXCMDSIZE];
char *argv[MAXARGS+1];
int nargs=0;
char *s;
int pid, status;
if (strlen(cmd) >= sizeof(tmp)) {
errno = E2BIG;
return -1;
}
strcpy(tmp, cmd);
for (s = strtok(tmp, " \t"); s; s = strtok(NULL, " \t")) {
if (nargs < MAXARGS) {
argv[nargs++] = s;
}
else {
errno = E2BIG;
return 1;
}
}
argv[nargs] = NULL;
pid = fork();
switch (pid) {
case -1:
return -1;
case 0:
/* child */
execv(argv[0], argv);
/* exec only returns if it fails */
_exit(255);
default:
/* parent */
waitpid(pid, &status, 0);
return status;
}
}