安卓输入子系统之inotify与epoll机制【学习笔记】【原创】

 1 #include <unistd.h>
 2 #include <stdio.h>
 3 #include <sys/inotify.h>
 4 #include <string.h>
 5 #include <errno.h>
 6 
 7 
 8 int read_process_inotify_fd(int fd)
 9 {
10     char event_buf[512];
11     int event_size;
12     int event_pos = 0;
13     int res;
14     struct inotify_event *event;
15     
16 
17     res = read(fd, event_buf, sizeof(event_buf));
18     if(res < (int)sizeof(*event)) {
19         if(errno == EINTR)
20             return 0;
21         printf("could not get event, %s\n", strerror(errno));
22         return -1;
23     }
24 
25     while(res >= (int)sizeof(*event)) {
26         event = (struct inotify_event *)(event_buf + event_pos);
27         //printf("%d: %08x \"%s\"\n", event->wd, event->mask, event->len ? event->name : "");
28         if(event->len) {
29             if(event->mask & IN_CREATE) {
30                 //openDeviceLocked(devname);
31                 printf("Create file: %s\r\n",event->name);
32             } else {
33                 //closeDeviceByPathLocked(devname);
34                 printf("delete file: %s\r\n",event->name);
35             }
36         }
37         event_size = sizeof(*event) + event->len;
38         res -= event_size;
39         event_pos += event_size;
40     }
41 
42     return 0;
43 
44 }
45 
46 int main(int argc,char **argv)
47 {
48     int mINotifyFd;
49     int result;
50 
51     if (argc != 2){
52         printf("Usage: %s <dir> \r\n",argv[0]);
53         return -1;
54     }
55 
56     mINotifyFd = inotify_init();
57     if (mINotifyFd <= 0){
58         printf("Error inotify_init\r\n");
59         return -1;
60     }
61 
62     
63     result = inotify_add_watch(mINotifyFd, argv[1], IN_DELETE | IN_CREATE);
64 
65     while(1){
66         read_process_inotify_fd(mINotifyFd);
67     }
68     
69     
70 
71     return 0;
72 }

 1 #include <sys/epoll.h>
 2 #include <stdio.h>
 3 #include <unistd.h>
 4 #include <sys/types.h>
 5 #include <sys/stat.h>
 6 #include <fcntl.h>
 7 #include <string.h>
 8 
 9 
10 static const int EPOLL_SIZE_HINT = 8;
11 static const int EPOLL_MAX_EVENTS = 16;
12 
13 #define DATA_MAX_LEN 512
14 
15 
16 int add_to_epoll(int fd,int epollfd)
17 {
18     int result;
19     struct epoll_event eventItem;
20     
21     memset(&eventItem, 0, sizeof(eventItem));
22     eventItem.events = EPOLLIN;
23     eventItem.data.fd = fd;
24     result = epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &eventItem);
25 
26     return result;
27 }
28 
29 void rm_from_epoll(int fd,int epollfd)
30 {
31      epoll_ctl(epollfd, EPOLL_CTL_DEL, fd, NULL);    
32 }
33 
34 int main(int argc,char **argv)
35 {
36     int mEpollFd;
37     int tmp_fd;
38     int pollResult;
39     int i;
40     int len;
41     char buf[DATA_MAX_LEN];
42     
43     struct epoll_event mPendingEventItems[EPOLL_MAX_EVENTS];
44 
45     if(argc < 2){
46         printf("Usage: %s <file1> [file2] [file3]\r\n",argv[0]);
47         return -1;
48     }
49     
50     
51     mEpollFd = epoll_create(EPOLL_SIZE_HINT);
52     if (mEpollFd < 0){
53         printf("Error epoll_create\r\n");
54         return -1;
55     }
56 
57     for(i = 0;i < argc;i ++){
58         tmp_fd = open(argv[i],O_RDWR);
59         add_to_epoll(tmp_fd,mEpollFd);
60     }
61 
62     while(1){
63         pollResult = epoll_wait(mEpollFd, mPendingEventItems, EPOLL_MAX_EVENTS, -1);
64         
65         for(i = 0 ;i < pollResult;i ++){
66             printf("Reason: 0x%x\r\n",mPendingEventItems[i].events);
67             len = read(mPendingEventItems[i].data.fd,buf,DATA_MAX_LEN);
68             buf[len] = ‘\0‘;
69             printf("get data:%s\r\n",buf);
70         }
71         sleep(5);
72     }
73     
74 
75     return 0;
76 }