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 <linux/watchdog.h>
20 #include <stdlib.h>
21 #include <string.h>
22 #include <unistd.h>
23 
24 #include <android-base/logging.h>
25 
26 #include "log.h"
27 
28 #ifdef _INIT_INIT_H
29 #error "Do not include init.h in files used by ueventd or watchdogd; it will expose init's globals"
30 #endif
31 
32 #define DEV_NAME "/dev/watchdog"
33 
34 namespace android {
35 namespace init {
36 
37 int watchdogd_main(int argc, char **argv) {
38     InitKernelLogging(argv);
39 
40     int interval = 10;
41     if (argc >= 2) interval = atoi(argv[1]);
42 
43     int margin = 10;
44     if (argc >= 3) margin = atoi(argv[2]);
45 
46     LOG(INFO) << "watchdogd started (interval " << interval << ", margin " << margin << ")!";
47 
48     int fd = open(DEV_NAME, O_RDWR|O_CLOEXEC);
49     if (fd == -1) {
50         PLOG(ERROR) << "Failed to open " << DEV_NAME;
51         return 1;
52     }
53 
54     int timeout = interval + margin;
55     int ret = ioctl(fd, WDIOC_SETTIMEOUT, &timeout);
56     if (ret) {
57         PLOG(ERROR) << "Failed to set timeout to " << timeout;
58         ret = ioctl(fd, WDIOC_GETTIMEOUT, &timeout);
59         if (ret) {
60             PLOG(ERROR) << "Failed to get timeout";
61         } else {
62             if (timeout > margin) {
63                 interval = timeout - margin;
64             } else {
65                 interval = 1;
66             }
67             LOG(WARNING) << "Adjusted interval to timeout returned by driver: "
68                          << "timeout " << timeout
69                          << ", interval " << interval
70                          << ", margin " << margin;
71         }
72     }
73 
74     while (true) {
75         write(fd, "", 1);
76         sleep(interval);
77     }
78 }
79 
80 }  // namespace init
81 }  // namespace android
82