inotify和epoll

参考EventHub.cpp

1、初始化inotify

int mINotifyFd = inotify_init();

2、将要监测的目录添加到inotify

inotify。int result = inotify_add_watch(mINotifyFd, argv[1], IN_DELETE | IN_CREATE);

3、读inotify有没有event

#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/inotify.h>
#include <stdio.h>int read_process_inotify_fd(int fd)
{int res;char event_buf[512];int event_size;int event_pos = 0;struct inotify_event *event;res = read(fd, event_buf, sizeof(event_buf));if(res < (int)sizeof(*event)) {if(errno == EINTR)return 0;printf("could not get event, %s\n", strerror(errno));return -1;}while(res >= (int)sizeof(*event)) {event = (struct inotify_event *)(event_buf + event_pos);//printf("%d: %08x \"%s\"\n", event->wd, event->mask, event->len ? event->name : "");if(event->len) {if(event->mask & IN_CREATE) {printf("create file: %s\n", event->name);} else {printf("delete file: %s\n", event->name);}}event_size = sizeof(*event) + event->len;res -= event_size;event_pos += event_size;}return 0;}int main(int argc, char **argv)
{int ret;if (argc != 2) {printf("Usage: %s <dir>\n", argv[0]);return -1;}int mINotifyFd = inotify_init();int result = inotify_add_watch(mINotifyFd, argv[1], IN_DELETE | IN_CREATE);if (result < 0) {printf("inotify_add_watch error\n");return -1;}while (1) {ret = read_process_inotify_fd(mINotifyFd);if (ret) {printf("read_process_inotify_fd error\n");return -1;}}return 0;
}

 1、创建epoll

int mEpollFd = epoll_create(5);

2、打开fifo路径，添加到epoll

epoll_create，3、epoll_wait

4、读数据

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/epoll.h>
#include <unistd.h>/** typedef union epoll_data {void    *ptr;int      fd;uint32_t u32;uint64_t u64;} epoll_data_t;struct epoll_event {uint32_t     events;    /* Epoll events *//*              epoll_data_t data;      /* User data variable *//*          };*/#define MAXEVENTS     10
#define MAXLEN        512
static struct epoll_event eventItem[MAXEVENTS];int epoll_add_watch(int mEpollFd, int fd)
{struct epoll_event eventItem;memset(&eventItem, 0, sizeof(eventItem));eventItem.events = EPOLLIN;eventItem.data.fd = fd;int result = epoll_ctl(mEpollFd, EPOLL_CTL_ADD, fd, &eventItem);return result;
}int main(int argc, char **argv)
{int res;char buf[MAXLEN];if (argc < 2) {printf("Usage: ./epoll <fifo1> <fifo2> ...\n");return -1;}int mEpollFd = epoll_create(5);  //最多监听5个文件if (mEpollFd < 0) {printf("epoll_create error\n");return -1;}int i;for (i = 1; i < argc; i++) {int fd = open(argv[i], O_RDWR);if (fd < 0) {printf("open %s error\n", argv[i]);return -1;}res = epoll_add_watch(mEpollFd, fd);if (res) {printf("epoll_add_watch error\n");return -1;}}while (1) {int poll_result = epoll_wait(mEpollFd, eventItem, MAXEVENTS, -1);for (i = 0; i < poll_result; i++) {int len = read(eventItem[i].data.fd, buf, MAXLEN);buf[len] = '\0';printf("get data : %s\n", buf);}    }return 0;}

inotify和epoll同时使用，即能监测到有没有新的文件创建，还能读出文件内容

 

#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/inotify.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/epoll.h>static int mEpollFd;
#define MAXEVENTS     10
#define MAXLEN        512
#define MAXFD         512static char *DIR_NAME;
static struct epoll_event eventItem[MAXEVENTS];char *file_and_fd[MAXFD];int epoll_add_watch(int fd)
{struct epoll_event eventItem;memset(&eventItem, 0, sizeof(eventItem));eventItem.events = EPOLLIN;eventItem.data.fd = fd;int result = epoll_ctl(mEpollFd, EPOLL_CTL_ADD, fd, &eventItem);return result;
}void epoll_rm_watch(int fd)
{epoll_ctl(mEpollFd, EPOLL_CTL_DEL, fd, NULL);}//打开文件并加入epoll监听
int open_file_add_epoll(char *filename)
{int fd = open(filename, O_RDWR);if (fd < 0) {printf("open %s error\n", filename);return -1;}file_and_fd[fd] = filename;int res = epoll_add_watch(fd);if (res) {printf("epoll_add_watch error\n");return -1;}
}int find_fd(char *name)
{int i;for (i = 0; i < MAXFD; i++) {if (strcmp(file_and_fd[i], name) == 0)return i;}return -1;
}int read_process_inotify_fd(int fd)
{int res;char file_path[20];char event_buf[512];int event_size;int event_pos = 0;struct inotify_event *event;res = read(fd, event_buf, sizeof(event_buf));if(res < (int)sizeof(*event)) {if(errno == EINTR)return 0;printf("could not get event, %s\n", strerror(errno));return -1;}while(res >= (int)sizeof(*event)) {event = (struct inotify_event *)(event_buf + event_pos);//printf("%d: %08x \"%s\"\n", event->wd, event->mask, event->len ? event->name : "");if(event->len) {sprintf(file_path, "%s/%s", DIR_NAME, event->name);if(event->mask & IN_CREATE) {printf("create file: %s\n", event->name);open_file_add_epoll(file_path);} else {printf("delete file: %s\n", event->name);int file_fd = find_fd(file_path);epoll_rm_watch(file_fd);}}event_size = sizeof(*event) + event->len;res -= event_size;event_pos += event_size;}return 0;}int main(int argc, char **argv)
{int ret;int i;if (argc != 2) {printf("Usage: %s <dir>\n", argv[0]);return -1;}char buf[MAXLEN];int mINotifyFd = inotify_init();int result = inotify_add_watch(mINotifyFd, argv[1], IN_DELETE | IN_CREATE);if (result < 0) {printf("inotify_add_watch error\n");return -1;}DIR_NAME = argv[1];mEpollFd = epoll_create(5);  if (mEpollFd < 0) {printf("epoll_create error\n");return -1;}epoll_add_watch(mINotifyFd);  //监测目录while (1) {int poll_result = epoll_wait(mEpollFd, eventItem, MAXEVENTS, -1);for (i = 0; i < poll_result; i++) {if (eventItem[i].data.fd == mINotifyFd) {    //有新文件创建， 目录argv[1]里面有变化ret = read_process_inotify_fd(mINotifyFd);if (ret) {printf("read_process_inotify_fd error\n");return -1;}}else{                             //文件的内容有变化int len = read(eventItem[i].data.fd, buf, MAXLEN);buf[len] = '\0';printf("get data : %s\n", buf);}}}return 0;
}