109 lines
2.7 KiB
C
109 lines
2.7 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Mini watch implementation for busybox
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*
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* Copyright (C) 2001 by Michael Habermann <mhabermann@gmx.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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/* BB_AUDIT SUSv3 N/A */
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/* BB_AUDIT GNU defects -- only option -n is supported. */
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/* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org)
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*
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* Removed dependency on date_main(), added proper error checking, and
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* reduced size.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <limits.h>
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#include <time.h>
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#include <assert.h>
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#include <unistd.h>
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#include <sys/wait.h>
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#include "busybox.h"
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int watch_main(int argc, char **argv)
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{
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const int header_len = 40;
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time_t t;
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pid_t pid;
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unsigned period = 2;
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int old_stdout;
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int len, len2;
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char **watched_argv;
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char header[header_len + 1];
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if (argc < 2) {
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bb_show_usage();
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}
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/* don't use getopt, because it permutes the arguments */
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++argv;
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if ((argc > 3) && !strcmp(*argv, "-n")
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) {
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period = bb_xgetularg10_bnd(argv[1], 1, UINT_MAX);
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argv += 2;
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}
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watched_argv = argv;
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/* create header */
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len = snprintf(header, header_len, "Every %ds:", period);
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/* Don't bother checking for len < 0, as it should never happen.
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* But, just to be prepared... */
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assert(len >= 0);
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do {
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len2 = strlen(*argv);
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if (len + len2 >= header_len-1) {
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break;
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}
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header[len] = ' ';
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memcpy(header+len+1, *argv, len2);
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len += len2+1;
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} while (*++argv);
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header[len] = 0;
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/* thanks to lye, who showed me how to redirect stdin/stdout */
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old_stdout = dup(STDOUT_FILENO);
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while (1) {
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time(&t);
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/* Use dprintf to avoid fflush()ing stdout. */
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if (dprintf(1, "\033[H\033[J%-*s%s\n", header_len, header, ctime(&t)) < 0) {
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bb_perror_msg_and_die("printf");
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}
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pid = vfork(); /* vfork, because of ucLinux */
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if (pid > 0) {
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//parent
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wait(0);
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sleep(period);
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} else if (0 == pid) {
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//child
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dup2(old_stdout, STDOUT_FILENO);
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execvp(*watched_argv, watched_argv);
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bb_perror_msg_and_die(*watched_argv);
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} else {
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bb_perror_msg_and_die("vfork");
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}
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}
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}
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