99 lines
2.3 KiB
C
99 lines
2.3 KiB
C
/* $NetBSD: shell_cmd.c,v 1.5 2000/10/04 16:24:49 sommerfeld Exp $ */
|
|
|
|
/*
|
|
* shell_cmd() takes a shell command after %<character> substitutions. The
|
|
* command is executed by a /bin/sh child process, with standard input,
|
|
* standard output and standard error connected to /dev/null.
|
|
*
|
|
* Diagnostics are reported through syslog(3).
|
|
*
|
|
* Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
#ifndef lint
|
|
#if 0
|
|
static char sccsid[] = "@(#) shell_cmd.c 1.5 94/12/28 17:42:44";
|
|
#else
|
|
__RCSID("$NetBSD: shell_cmd.c,v 1.5 2000/10/04 16:24:49 sommerfeld Exp $");
|
|
#endif
|
|
#endif
|
|
|
|
/* System libraries. */
|
|
|
|
#include <sys/types.h>
|
|
#include <sys/param.h>
|
|
#include <sys/wait.h>
|
|
#include <signal.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <unistd.h>
|
|
#include <fcntl.h>
|
|
#include <syslog.h>
|
|
#include <string.h>
|
|
|
|
/* Local stuff. */
|
|
|
|
#include "tcpd.h"
|
|
|
|
/* Forward declarations. */
|
|
|
|
static void do_child __P((char *));
|
|
|
|
/* shell_cmd - execute shell command */
|
|
|
|
void shell_cmd(command)
|
|
char *command;
|
|
{
|
|
int child_pid;
|
|
int wait_pid;
|
|
|
|
/*
|
|
* Most of the work is done within the child process, to minimize the
|
|
* risk of damage to the parent.
|
|
*/
|
|
|
|
switch (child_pid = fork()) {
|
|
case -1: /* error */
|
|
tcpd_warn("cannot fork: %m");
|
|
break;
|
|
case 00: /* child */
|
|
do_child(command);
|
|
/* NOTREACHED */
|
|
default: /* parent */
|
|
while ((wait_pid = wait((int *) 0)) != -1 && wait_pid != child_pid)
|
|
/* void */ ;
|
|
}
|
|
}
|
|
|
|
/* do_child - exec command with { stdin, stdout, stderr } to /dev/null */
|
|
|
|
static void do_child(command)
|
|
char *command;
|
|
{
|
|
int tmp_fd;
|
|
|
|
/*
|
|
* Systems with POSIX sessions may send a SIGHUP to grandchildren if the
|
|
* child exits first. This is sick, sessions were invented for terminals.
|
|
*/
|
|
|
|
signal(SIGHUP, SIG_IGN);
|
|
|
|
/* Set up new stdin, stdout, stderr, and exec the shell command. */
|
|
|
|
for (tmp_fd = 0; tmp_fd < 3; tmp_fd++)
|
|
(void) close(tmp_fd);
|
|
if (open("/dev/null", 2) != 0) {
|
|
tcpd_warn("open /dev/null: %m");
|
|
} else if (dup(0) != 1 || dup(0) != 2) {
|
|
tcpd_warn("dup: %m");
|
|
} else {
|
|
(void) execl("/bin/sh", "sh", "-c", command, (char *) 0);
|
|
tcpd_warn("execl /bin/sh: %m");
|
|
}
|
|
|
|
/* Something went wrong. We MUST terminate the child process. */
|
|
_exit(0);
|
|
}
|