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/* vi: set sw=4 ts=4: */
/*
* Mini watch implementation for busybox
*
* Copyright (C) 2001 by Michael Habermann <mhabermann@gmx.de>
*
* 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
*
*/
/* BB_AUDIT SUSv3 N/A */
/* BB_AUDIT GNU defects -- only option -n is supported. */
/* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org)
*
* Removed dependency on date_main(), added proper error checking, and
* reduced size.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <time.h>
#include <assert.h>
#include <unistd.h>
#include <sys/wait.h>
#include "busybox.h"
int watch_main(int argc, char **argv)
{
const int header_len = 40;
time_t t;
pid_t pid;
unsigned period = 2;
int old_stdout;
int len, len2;
char **watched_argv;
char header[header_len + 1];
if (argc < 2) {
bb_show_usage();
}
/* don't use getopt, because it permutes the arguments */
++argv;
if ((argc > 3) && !strcmp(*argv, "-n")
) {
period = bb_xgetularg10_bnd(argv[1], 1, UINT_MAX);
argv += 2;
}
watched_argv = argv;
/* create header */
len = snprintf(header, header_len, "Every %ds:", period);
/* Don't bother checking for len < 0, as it should never happen.
* But, just to be prepared... */
assert(len >= 0);
do {
len2 = strlen(*argv);
if (len + len2 >= header_len-1) {
break;
}
header[len] = ' ';
memcpy(header+len+1, *argv, len2);
len += len2+1;
} while (*++argv);
header[len] = 0;
/* thanks to lye, who showed me how to redirect stdin/stdout */
old_stdout = dup(STDOUT_FILENO);
while (1) {
time(&t);
/* Use dprintf to avoid fflush()ing stdout. */
if (dprintf(1, "\033[H\033[J%-*s%s\n", header_len, header, ctime(&t)) < 0) {
bb_perror_msg_and_die("printf");
}
pid = vfork(); /* vfork, because of ucLinux */
if (pid > 0) {
//parent
wait(0);
sleep(period);
} else if (0 == pid) {
//child
dup2(old_stdout, STDOUT_FILENO);
execvp(*watched_argv, watched_argv);
bb_perror_msg_and_die(*watched_argv);
} else {
bb_perror_msg_and_die("vfork");
}
}
}
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