0ba8f25f0ea1423f6e897aecff384e3735cbf381
[project/procd.git] / watchdog.c
1 /*
2 * Copyright (C) 2013 Felix Fietkau <nbd@openwrt.org>
3 * Copyright (C) 2013 John Crispin <blogic@openwrt.org>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU Lesser General Public License version 2.1
7 * as published by the Free Software Foundation
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 */
14
15 #include <linux/watchdog.h>
16
17 #include <sys/ioctl.h>
18 #include <sys/types.h>
19 #include <sys/stat.h>
20 #include <fcntl.h>
21
22 #include <unistd.h>
23
24 #include <libubox/uloop.h>
25
26 #include "procd.h"
27 #include "watchdog.h"
28
29 #define WDT_PATH "/dev/watchdog"
30
31 static struct uloop_timeout wdt_timeout;
32 static int wdt_fd = -1;
33 static int wdt_frequency = 5;
34
35 static void watchdog_timeout_cb(struct uloop_timeout *t)
36 {
37 DEBUG(2, "Ping\n");
38 if (write(wdt_fd, "X", 1) < 0)
39 ERROR("WDT failed to write: %s\n", strerror(errno));
40 uloop_timeout_set(t, wdt_frequency * 1000);
41 }
42
43 int watchdog_timeout(int timeout)
44 {
45 if (wdt_fd < 0)
46 return 0;
47
48 if (timeout) {
49 DEBUG(2, "Set watchdog timeout: %ds\n", timeout);
50 ioctl(wdt_fd, WDIOC_SETTIMEOUT, &timeout);
51 }
52 ioctl(wdt_fd, WDIOC_GETTIMEOUT, &timeout);
53
54 return timeout;
55 }
56
57 int watchdog_frequency(int frequency)
58 {
59 if (wdt_fd < 0)
60 return 0;
61
62 if (frequency) {
63 DEBUG(2, "Set watchdog frequency: %ds\n", frequency);
64 wdt_frequency = frequency;
65 }
66
67 return wdt_frequency;
68 }
69
70 char* watchdog_fd(void)
71 {
72 static char fd_buf[3];
73
74 if (wdt_fd < 0)
75 return NULL;
76 snprintf(fd_buf, sizeof(fd_buf), "%d", wdt_fd);
77
78 return fd_buf;
79 }
80
81 void watchdog_init(void)
82 {
83 char *env = getenv("WDTFD");
84
85 wdt_timeout.cb = watchdog_timeout_cb;
86 if (env) {
87 LOG("- watchdog -\n");
88 DEBUG(1, "Watchdog handover: fd=%s\n", env);
89 wdt_fd = atoi(env);
90 fcntl(wdt_fd, F_SETFD, fcntl(wdt_fd, F_GETFD) | FD_CLOEXEC);
91 unsetenv("WDTFD");
92 } else {
93 wdt_fd = open("/dev/watchdog", O_WRONLY);
94 if (getpid() != 1)
95 fcntl(wdt_fd, F_SETFD, fcntl(wdt_fd, F_GETFD) | FD_CLOEXEC);
96 }
97 if (wdt_fd < 0)
98 return;
99 watchdog_timeout(30);
100 watchdog_timeout_cb(&wdt_timeout);
101
102 DEBUG(2, "Opened watchdog with timeout %ds\n", watchdog_timeout(0));
103 }