Contents of /tags/mkinitrd-6_3_3/busybox/miscutils/watchdog.c
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Wed Dec 15 21:43:57 2010 UTC (13 years, 9 months ago) by niro
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Wed Dec 15 21:43:57 2010 UTC (13 years, 9 months ago) by niro
File MIME type: text/plain
File size: 2923 byte(s)
tagged 'mkinitrd-6_3_3'
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * Mini watchdog implementation for busybox |
4 | * |
5 | * Copyright (C) 2003 Paul Mundt <lethal@linux-sh.org> |
6 | * Copyright (C) 2006 Bernhard Reutner-Fischer <busybox@busybox.net> |
7 | * Copyright (C) 2008 Darius Augulis <augulis.darius@gmail.com> |
8 | * |
9 | * Licensed under the GPL v2 or later, see the file LICENSE in this tarball. |
10 | */ |
11 | |
12 | #include "libbb.h" |
13 | #include "linux/types.h" /* for __u32 */ |
14 | #include "linux/watchdog.h" |
15 | |
16 | #define OPT_FOREGROUND (1 << 0) |
17 | #define OPT_STIMER (1 << 1) |
18 | #define OPT_HTIMER (1 << 2) |
19 | |
20 | static void watchdog_shutdown(int sig UNUSED_PARAM) |
21 | { |
22 | static const char V = 'V'; |
23 | |
24 | write(3, &V, 1); /* Magic, see watchdog-api.txt in kernel */ |
25 | if (ENABLE_FEATURE_CLEAN_UP) |
26 | close(3); |
27 | exit(EXIT_SUCCESS); |
28 | } |
29 | |
30 | int watchdog_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
31 | int watchdog_main(int argc, char **argv) |
32 | { |
33 | static const struct suffix_mult suffixes[] = { |
34 | { "ms", 1 }, |
35 | { "", 1000 }, |
36 | { "", 0 } |
37 | }; |
38 | |
39 | unsigned opts; |
40 | unsigned stimer_duration; /* how often to restart */ |
41 | unsigned htimer_duration = 60000; /* reboots after N ms if not restarted */ |
42 | char *st_arg; |
43 | char *ht_arg; |
44 | |
45 | opt_complementary = "=1"; /* must have exactly 1 argument */ |
46 | opts = getopt32(argv, "Ft:T:", &st_arg, &ht_arg); |
47 | |
48 | /* We need to daemonize *before* opening the watchdog as many drivers |
49 | * will only allow one process at a time to do so. Since daemonizing |
50 | * is not perfect (child may run before parent finishes exiting), we |
51 | * can't rely on parent exiting before us (let alone *cleanly* releasing |
52 | * the watchdog fd -- something else that may not even be allowed). |
53 | */ |
54 | if (!(opts & OPT_FOREGROUND)) |
55 | bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv); |
56 | |
57 | if (opts & OPT_HTIMER) |
58 | htimer_duration = xatou_sfx(ht_arg, suffixes); |
59 | stimer_duration = htimer_duration / 2; |
60 | if (opts & OPT_STIMER) |
61 | stimer_duration = xatou_sfx(st_arg, suffixes); |
62 | |
63 | bb_signals(BB_FATAL_SIGS, watchdog_shutdown); |
64 | |
65 | /* Use known fd # - avoid needing global 'int fd' */ |
66 | xmove_fd(xopen(argv[argc - 1], O_WRONLY), 3); |
67 | |
68 | /* WDIOC_SETTIMEOUT takes seconds, not milliseconds */ |
69 | htimer_duration = htimer_duration / 1000; |
70 | #ifndef WDIOC_SETTIMEOUT |
71 | # error WDIOC_SETTIMEOUT is not defined, cannot compile watchdog applet |
72 | #else |
73 | # if defined WDIOC_SETOPTIONS && defined WDIOS_ENABLECARD |
74 | { |
75 | static const int enable = WDIOS_ENABLECARD; |
76 | ioctl_or_warn(3, WDIOC_SETOPTIONS, (void*) &enable); |
77 | } |
78 | # endif |
79 | ioctl_or_warn(3, WDIOC_SETTIMEOUT, &htimer_duration); |
80 | #endif |
81 | |
82 | #if 0 |
83 | ioctl_or_warn(3, WDIOC_GETTIMEOUT, &htimer_duration); |
84 | printf("watchdog: SW timer is %dms, HW timer is %ds\n", |
85 | stimer_duration, htimer_duration * 1000); |
86 | #endif |
87 | |
88 | while (1) { |
89 | /* |
90 | * Make sure we clear the counter before sleeping, |
91 | * as the counter value is undefined at this point -- PFM |
92 | */ |
93 | write(3, "", 1); /* write zero byte */ |
94 | usleep(stimer_duration * 1000L); |
95 | } |
96 | return EXIT_SUCCESS; /* - not reached, but gcc 4.2.1 is too dumb! */ |
97 | } |