watchdogd.cpp revision 636b1ebd382a57b623c7c8e5b010d6fc626a20d3 
1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <errno.h>
18#include <fcntl.h>
19#include <stdlib.h>
20#include <string.h>
21#include <unistd.h>
22
23#include <linux/watchdog.h>
24
25#include "log.h"
26#include "util.h"
27
28#define DEV_NAME "/dev/watchdog"
29
30int watchdogd_main(int argc, char **argv) {
31    open_devnull_stdio();
32    klog_init();
33    klog_set_level(KLOG_NOTICE_LEVEL);
34
35    int interval = 10;
36    if (argc >= 2) interval = atoi(argv[1]);
37
38    int margin = 10;
39    if (argc >= 3) margin = atoi(argv[2]);
40
41    NOTICE("started (interval %d, margin %d)!\n", interval, margin);
42
43    int fd = open(DEV_NAME, O_RDWR|O_CLOEXEC);
44    if (fd == -1) {
45        ERROR("Failed to open %s: %s\n", DEV_NAME, strerror(errno));
46        return 1;
47    }
48
49    int timeout = interval + margin;
50    int ret = ioctl(fd, WDIOC_SETTIMEOUT, &timeout);
51    if (ret) {
52        ERROR("Failed to set timeout to %d: %s\n", timeout, strerror(errno));
53        ret = ioctl(fd, WDIOC_GETTIMEOUT, &timeout);
54        if (ret) {
55            ERROR("Failed to get timeout: %s\n", strerror(errno));
56        } else {
57            if (timeout > margin) {
58                interval = timeout - margin;
59            } else {
60                interval = 1;
61            }
62            WARNING("Adjusted interval to timeout returned by driver:"
63                    " timeout %d, interval %d, margin %d\n",
64                    timeout, interval, margin);
65        }
66    }
67
68    while (true) {
69        write(fd, "", 1);
70        sleep(interval);
71    }
72}
73