文件读写监控(inotify, systemtap)

#include <stdio.h>
#include <stdlib.h>
#include <sys/inotify.h>
#include <errno.h>
#include <string.h>
#include <sys/epoll.h>
 
int main(void)
{
    char *filename = "./log.txt";
 
    int inoti_fd = inotify_init1(IN_CLOEXEC);
    if (inoti_fd == -1) {
        printf("inotify_init failed, %s\n", strerror(errno));
        exit(-1);
    }
 
    int file_fd = inotify_add_watch(inoti_fd, filename, IN_ALL_EVENTS);
    if (file_fd == -1) {
        printf("inotify_add_watch failed, %s\n", strerror(errno));
        exit(-1);
    }
 
    int epoll_fd = epoll_create(5);
    if (epoll_fd == -1) {
        printf("epoll_create failed, %s\n", strerror(errno));
        goto end;
    }
 
    struct epoll_event ev, event[5];
 
    memset(&ev, 0, sizeof(ev));
    ev.events = EPOLLIN | EPOLLET;
    ev.data.fd = inoti_fd;
    if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, inoti_fd, &ev) == -1) {
        printf("epoll_ctl failed, %s\n", strerror(errno));
        goto end;
    }
 
    int buf_size = sizeof(struct inotify_event) + 64 * sizeof(char);
    struct inotify_event * instance = malloc(buf_size);
    memset(instance, 0, buf_size);
 
    int value = 0;
    while ((value = epoll_wait(epoll_fd, event, 5, -1)) != -1) {
        int i = 0;
        for (i = 0; i < value; i ++) {
            if (event[i].data.fd == inoti_fd) {
                if (read(inoti_fd, instance, buf_size) > 0)
                    printf("file_id is %d, event is %u, cookie is %u, name is %s\n",
                            instance->wd, instance->mask, instance->cookie, instance->name);
                else
                    printf("read inoti_fd failed, %s\n", strerror(errno));
            }
            else
                printf("unknown file_fd %d\n", event[i].data.fd);
        }
    }
 
end:
    inotify_rm_watch(inoti_fd, file_fd);
 
    return 0;

#!/usr/bin/python
 
import logging
from inotify import adapters
 
_DEFAULT_LOG_FORMAT = ‘%(asctime)s - %(name)s - %(levelname)s - %(message)s‘
 
_LOGGER = logging.getLogger(__name__)
 
def _configure_logging():
    _LOGGER.setLevel(logging.DEBUG)
    ch = logging.FileHandler(‘./record‘, ‘a‘)
    formatter = logging.Formatter(_DEFAULT_LOG_FORMAT)
    ch.setFormatter(formatter)
    _LOGGER.addHandler(ch)
 
def _main():
    i = adapters.Inotify()
    i.add_watch(‘/var/lib/logrotate.status‘)
 
    for event in i.event_gen():
        if event:
            (header, type_names, watch_path, filename) = event
            print ("WD=(%d) MASK=(%d) COOKIE=(%d) LEN=(%d) MASK->NAMES=%s WATCH-PATH=[%s] FILENAME=[%s]",            header.wd, header.mask, header.cookie, header.len, type_names, watch_path.decode(‘utf-8‘), filename.decode(‘utf-8‘))
            _LOGGER.info("WD=(%d) MASK=(%d) COOKIE=(%d) LEN=(%d) MASK->NAMES=%s WATCH-PATH=[%s] FILENAME=[%s]",            header.wd, header.mask, header.cookie, header.len, type_names, watch_path.decode(‘utf-8‘), filename.decode(‘utf-8‘))
 
if __name__ == ‘__main__‘:
    _configure_logging()
    _main()

#监控log.txt发生的操作，并输出到record文件中，另外inotifywait命令的-r选项支持递归遍历
$ inotifywait -m log.txt -o record
 
#inotifywatch 命令则用于统计一段时间内，某个文件所发生操作的统计数据
#上述的两个命令的具体用法参照man手册

$ yum install systemtab -y
$ yum install kernel-debug-debuginfo     #stap监控系统调用需要
$ stap -ve ‘probe begin { log("hello world") exit() }‘     #测试stap是否安装成功
$ ls -i log.txt      #查看要监控文件的inode号 2360637
$ df -h      #查看log.txt所在的磁盘分区
$ cat /proc/partitions     #查看各个磁盘分区的major、minor号 8 2
$ stap /usr/share/doc/systemtap-1.6/examples/io/inodewatch.stp 0x8 0x2 2360637     #监控log.txt即（0x8 0x2 2360637）所进行的操作，同时会显示出执行操作的进程ID