hush/coreutils/watch.c
2002-09-17 20:53:41 +00:00

103 lines
2.4 KiB
C

/* 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
*
*/
/* getopt not needed */
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include "busybox.h"
extern int watch_main(int argc, char **argv)
{
const char date_argv[2][10] = { "date", "" };
const int header_len = 40;
char header[header_len + 1];
int period = 2;
char **cargv;
int cargc;
pid_t pid;
int old_stdout;
int i;
if (argc < 2) {
show_usage();
} else {
cargv = argv + 1;
cargc = argc - 1;
/* don't use getopt, because it permutes the arguments */
if (argc >= 3 && !strcmp(argv[1], "-n")) {
period = strtol(argv[2], NULL, 10);
if (period < 1)
show_usage();
cargv += 2;
cargc -= 2;
}
}
/* create header */
snprintf(header, header_len, "Every %ds: ", period);
for (i = 0; i < cargc && (strlen(header) + strlen(cargv[i]) < header_len);
i++) {
strcat(header, cargv[i]);
strcat(header, " ");
}
/* fill with blanks */
for (i = strlen(header); i < header_len; i++)
header[i] = ' ';
header[header_len - 1] = '\0';
/* thanks to lye, who showed me how to redirect stdin/stdout */
old_stdout = dup(1);
while (1) {
printf("\033[H\033[J%s", header);
date_main(1, (char **) date_argv);
printf("\n");
pid = vfork(); /* vfork, because of ucLinux */
if (pid > 0) {
//parent
wait(0);
sleep(period);
} else if (0 == pid) {
//child
close(1);
dup(old_stdout);
if (execvp(*cargv, cargv))
error_msg_and_die("Couldn't run command\n");
} else {
error_msg_and_die("Couldn't vfork\n");
}
}
return EXIT_SUCCESS;
}