[821] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * Mini watchdog implementation for busybox
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| 4 | *
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| 5 | * Copyright (C) 2003 Paul Mundt <lethal@linux-sh.org>
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| 6 | * Copyright (C) 2006 Bernhard Fischer <busybox@busybox.net>
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| 7 | *
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| 8 | * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
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| 9 | */
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| 10 |
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| 11 | #include "busybox.h"
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| 12 | #include <stdio.h>
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| 13 | #include <fcntl.h>
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| 14 | #include <unistd.h>
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| 15 | #include <stdlib.h>
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| 16 | #include <signal.h>
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| 17 |
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| 18 | #define OPT_FOREGROUND 0x01
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| 19 | #define OPT_TIMER 0x02
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| 20 |
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| 21 | /* Watchdog file descriptor */
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| 22 | static int fd;
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| 23 |
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| 24 | static void watchdog_shutdown(int ATTRIBUTE_UNUSED unused)
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| 25 | {
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| 26 | write(fd, "V", 1); /* Magic, see watchdog-api.txt in kernel */
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| 27 | close(fd);
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| 28 | exit(0);
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| 29 | }
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| 30 |
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| 31 | int watchdog_main(int argc, char **argv)
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| 32 | {
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| 33 | unsigned long opts;
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| 34 | unsigned long timer_duration = 30; /* Userspace timer duration, in seconds */
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| 35 | char *t_arg;
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| 36 |
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| 37 | opts = bb_getopt_ulflags(argc, argv, "Ft:", &t_arg);
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| 38 |
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| 39 | if (opts & OPT_TIMER)
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| 40 | timer_duration = bb_xgetlarg(t_arg, 10, 0, INT_MAX);
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| 41 |
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| 42 | /* We're only interested in the watchdog device .. */
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| 43 | if (optind < argc - 1 || argc == 1)
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| 44 | bb_show_usage();
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| 45 |
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| 46 | #ifdef BB_NOMMU
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| 47 | if (!(opts & OPT_FOREGROUND))
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| 48 | vfork_daemon_rexec(0, 1, argc, argv, "-F");
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| 49 | #else
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| 50 | bb_xdaemon(0, 1);
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| 51 | #endif
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| 52 |
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| 53 | signal(SIGHUP, watchdog_shutdown);
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| 54 | signal(SIGINT, watchdog_shutdown);
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| 55 |
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| 56 | fd = bb_xopen(argv[argc - 1], O_WRONLY);
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| 57 |
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| 58 | while (1) {
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| 59 | /*
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| 60 | * Make sure we clear the counter before sleeping, as the counter value
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| 61 | * is undefined at this point -- PFM
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| 62 | */
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| 63 | write(fd, "\0", 1);
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| 64 | sleep(timer_duration);
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| 65 | }
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| 66 |
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| 67 | watchdog_shutdown(0);
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| 68 |
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| 69 | return EXIT_SUCCESS;
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| 70 | }
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