inotify结合select监控目录下文件变动

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/inotify.h>
#include <string.h>

#include <sys/select.h>

#define EVENT_SIZE ( sizeof (struct inotify_event) )
#define BUF_LEN ( 1024 * (EVENT_SIZE + 16) )

#define MAXLEN 1024

char buffer[BUF_LEN];
fd_set set;
fd_set rset;
int check_set[MAXLEN];
int max_fd;
int arrlen = 0;

static void handle_read(int fd)
{
    int length = read(fd, buffer, BUF_LEN);
    if (length < 0) {
        perror("read");
    }

    int i=0; 
    while (i < length) {
        struct inotify_event *event = (struct inotify_event *)&buffer[i];
        if (event->len) {
            if (event->mask & IN_CREATE) {
                if (event->mask & IN_ISDIR) {
                    printf("The directory %s was created.\n", event->name);
                } else {
                    printf("The file %s was created.\n", event->name);
                }
            } else if (event->mask & IN_DELETE) {
                if (event->mask & IN_ISDIR) {
                    printf("The directory %s was deleted.\n", event->name);
                } else {
                    printf("The file %s was deleted.\n", event->name);
                }
            } else if (event->mask & IN_MODIFY) {
                if (event->mask & IN_ISDIR) {
                    printf("The directory %s was modified.\n", event->name);
                } else {
                    printf("The file %s was modified. wd:%d\n", event->name, event->wd);
                }
            }
        }
        i += EVENT_SIZE + event->len;
    }
    memset(buffer, 0, BUF_LEN);
}

static void do_select() 
{
    int i=0;
    while (1) {
        set = rset;
        int nready = select(max_fd+1, &set, NULL, NULL, NULL);
        if (nready == -1) {
            perror("error select !");
            exit(-1);
        } else if (nready == 0) {
            printf("timeout!");
            continue;
        }

        for (i=0; i<arrlen; ++I) { //轮询数据连接
            int set_fd = check_set[i];
            if (FD_ISSET(set_fd, &set)) {
                handle_read(set_fd);
            }
        }
    }
}

static void AddFd(int fd)
{
    FD_SET(fd, &rset);
    check_set[arrlen++] = fd;

    if (max_fd < fd)
        max_fd = fd;
}

int main( int argc, char **argv )
{
 
    int fd = inotify_init();
    if ( fd < 0 ) {
        perror( "inotify_init" );
    }
    int wd = inotify_add_watch( fd, "./tmp",IN_MODIFY | IN_CREATE | IN_DELETE );
 
    int fd2 = inotify_init(); //也可以直接用fd不用重新inotify_init
    int wd2 = inotify_add_watch( fd2, "./tmp1",IN_MODIFY | IN_CREATE | IN_DELETE );
 
    //初始化
    FD_ZERO(&rset);
    int i = 0;
    for(i = 0;i < MAXLEN; ++i)
          check_set[i] = -1;
    //添加监控fd
    AddFd(fd);
    AddFd(fd2);
    //select轮询
    do_select();
 
    inotify_rm_watch(fd,wd);
    inotify_rm_watch(fd2,wd2);
    close(fd);
    close(fd2);
 
    exit( 0 );
}