inotify使用范例
好久没更新博客了，来写一篇！
一. 应用层接口:
1. 函数原型:
int fd = inotify_init ();
//添加一个watch, path 可以使文件或者目录, mask见
int wd = inotify_add_watch (fd, path, mask);
int ret = inotify_rm_watch (fd, wd);//移除一个watch
2.
struct inotify_event
代表一次事件:
IN_CREATE, IN_DELETE, IN_OPEN, IN_CLOSE
struct inotify_event {
int wd; /* watch descriptor */
uint32_t mask; /* watch mask */
uint32_t cookie; /* cookie to synchronize two events */
uint32_t len; /* length (including nulls) of name */
char name __flexarr; /* stub for possible name */};
3. 读取事件
//buf指向一个
inotify_event的数组, 根据BUF_LEN填充合适的event
size_t len = read (fd, buf, BUF_LEN);
ioctl( inotify_fd, FIONREAD, &bytes_to_read );
4. poll事件
fd也可以用select和poll函数
二. kernel接口
1. 函数原型:
struct inotify_handle *inotify_init(struct inotify_operations *ops);
inotify_init_watch(struct inotify_watch *watch);
s32 inotify_add_watch(struct inotify_handle *ih, struct inotify_watch *watch, struct inode *inode, u32 mask);
s32 inotify_find_watch(struct inotify_handle *ih, struct inode *inode, struct inotify_watch **watchp);
s32 inotify_find_update_watch(struct inotify_handle *ih, struct inode *inode, u32 mask);
int inotify_rm_wd(struct inotify_handle *ih, u32 wd);
int inotify_rm_watch(struct inotify_handle *ih, struct inotify_watch *watch);
void inotify_remove_watch_locked(struct inotify_handle *ih, struct inotify_watch *watch);
void inotify_destroy(struct inotify_handle *ih);
void get_inotify_watch(struct inotify_watch *watch);
void put_inotify_watch(struct inotify_watch *watch);
附上实现的代码：（哇哈哈）
inotify.h:
/*
* This header is used if cannot be found.
*
* Inode based directory notification for Linux
*
* Copyright (C) 2005 John McCutchan
*/
#ifndef _LINUX_INOTIFY_H
#define _LINUX_INOTIFY_H
#include
#include
#include
/*
* struct inotify_event - structure read from the inotify device for each event
*
* When you are watching a directory, you will receive the filename for events
* such as IN_CREATE, IN_DELETE, IN_OPEN, IN_CLOSE, ..., relative to the wd.
*/
struct inotify_event {
int wd; /* watch descriptor */
uint32_t mask; /* watch mask */
uint32_t cookie; /* cookie to synchronize two events */
uint32_t len; /* length (including nulls) of name */
char name __flexarr; /* stub for possible name */
};
/* the following are legal, implemented events that user-space can watch for */
#define IN_ACCESS 0x00000001 /* File was accessed */
#define IN_MODIFY 0x00000002 /* File was modified */
#define IN_ATTRIB 0x00000004 /* Metadata changed */
#define IN_CLOSE_WRITE 0x00000008 /* Writtable file was closed */
#define IN_CLOSE_NOWRITE 0x00000010 /* Unwrittable file closed */
#define IN_OPEN 0x00000020 /* File was opened */
#define IN_MOVED_FROM 0x00000040 /* File was moved from X */
#define IN_MOVED_TO 0x00000080 /* File was moved to Y */
#define IN_CREATE 0x00000100 /* Subfile was created */
#define IN_DELETE 0x00000200 /* Subfile was deleted */
#define IN_DELETE_SELF 0x00000400 /* Self was deleted */
#define IN_MOVE_SELF 0x00000800 /* Self was moved */
/* the following are legal events. they are sent as needed to any watch */
#define IN_UNMOUNT 0x00002000 /* Backing fs was unmounted */
#define IN_Q_OVERFLOW 0x00004000 /* Event queued overflowed */
#define IN_IGNORED 0x00008000 /* File was ignored */
/* helper events */
#define IN_CLOSE (IN_CLOSE_WRITE | IN_CLOSE_NOWRITE) /* close */
#define IN_MOVE (IN_MOVED_FROM | IN_MOVED_TO) /* moves */
/* special flags */
#define IN_ONLYDIR 0x01000000 /* only watch the path if it is a directory */
#define IN_DONT_FOLLOW 0x02000000 /* don't follow a sym link */
#define IN_MASK_ADD 0x20000000 /* add to the mask of an already existing watch */
#define IN_ISDIR 0x40000000 /* event occurred against dir */
#define IN_ONESHOT 0x80000000 /* only send event once */
/*
* All of the events - we build the list by hand so that we can add flags in
* the future and not break backward compatibility. Apps will get only the
* events that they originally wanted. Be sure to add new events here!
*/
#define IN_ALL_EVENTS (IN_ACCESS | IN_MODIFY | IN_ATTRIB | IN_CLOSE_WRITE | \
IN_CLOSE_NOWRITE | IN_OPEN | IN_MOVED_FROM | \
IN_MOVED_TO | IN_DELETE | IN_CREATE | IN_DELETE_SELF | \
IN_MOVE_SELF)
#if defined (__alpha__)
# define __NR_inotify_init 444
# define __NR_inotify_add_watch 445
# define __NR_inotify_rm_watch 446
#elif defined (__arm__)
# define __NR_inotify_init (__NR_SYSCALL_BASE+316)
# define __NR_inotify_add_watch (__NR_SYSCALL_BASE+317)
# define __NR_inotify_rm_watch (__NR_SYSCALL_BASE+318)
#elif defined (__frv__)
# define __NR_inotify_init 291
# define __NR_inotify_add_watch 292
# define __NR_inotify_rm_watch 293
#elif defined(__i386__)
# define __NR_inotify_init 291
# define __NR_inotify_add_watch 292
# define __NR_inotify_rm_watch 293
#elif defined (__ia64__)
# define __NR_inotify_init 1277
# define __NR_inotify_add_watch 1278
# define __NR_inotify_rm_watch 1279
#elif defined (__mips__)
# if _MIPS_SIM == _MIPS_SIM_ABI32
# define __NR_inotify_init (__NR_Linux + 284)
# define __NR_inotify_add_watch (__NR_Linux + 285)
# define __NR_inotify_rm_watch (__NR_Linux + 286)
# endif
# if _MIPS_SIM == _MIPS_SIM_ABI64
# define __NR_inotify_init (__NR_Linux + 243)
# define __NR_inotify_add_watch (__NR_Linux + 243)
# define __NR_inotify_rm_watch (__NR_Linux + 243)
# endif
# if _MIPS_SIM == _MIPS_SIM_NABI32
# define __NR_inotify_init (__NR_Linux + 247)
# define __NR_inotify_add_watch (__NR_Linux + 248)
# define __NR_inotify_rm_watch (__NR_Linux + 249)
# endif
#elif defined(__parisc__)
# define __NR_inotify_init (__NR_Linux + 269)
# define __NR_inotify_add_watch (__NR_Linux + 270)
# define __NR_inotify_rm_watch (__NR_Linux + 271)
#elif defined(__powerpc__) || defined(__powerpc64__)
# define __NR_inotify_init 275
# define __NR_inotify_add_watch 276
# define __NR_inotify_rm_watch 277
#elif defined (__s390__)
# define __NR_inotify_init 284
# define __NR_inotify_add_watch 285
# define __NR_inotify_rm_watch 286
#elif defined (__sh__)
# define __NR_inotify_init 290
# define __NR_inotify_add_watch 291
# define __NR_inotify_rm_watch 292
#elif defined (__sh64__)
# define __NR_inotify_init 318
# define __NR_inotify_add_watch 319
# define __NR_inotify_rm_watch 320
#elif defined (__sparc__) || defined (__sparc64__)
# define __NR_inotify_init 151
# define __NR_inotify_add_watch 152
# define __NR_inotify_rm_watch 156
#elif defined(__x86_64__)
# define __NR_inotify_init 253
# define __NR_inotify_add_watch 254
# define __NR_inotify_rm_watch 255
#else
# error "Unsupported architecture!"
#endif
static inline int inotify_init (void)
{
return syscall (__NR_inotify_init);
}
static inline int inotify_add_watch (int fd, const char *name, uint32_t mask)
{
return syscall (__NR_inotify_add_watch, fd, name, mask);
}
static inline int inotify_rm_watch (int fd, uint32_t wd)
{
return syscall (__NR_inotify_rm_watch, fd, wd);
}
#endif /* _LINUX_INOTIFY_H */
main.c:
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include "inotify.h"
void show_event(struct inotify_event *events, int num_event)
{
int i;
struct inotify_event *e =events;
for(i = 0; i < num_event; i++){
printf("wd = %d, mask = 0x%02x, cookie = %u, len = %u\n", e->wd, e->mask, e->cookie, e->len);
e++;
}
}
void show_data(char * dat, int len)
{
int i;
int line_num = 16;
for(i = 0; i < len; i ++){
if(i % line_num == 0 && i != 0) printf("\n");
printf("0x%02x ", dat[i]);
}
printf("\n----------------------------------------\n");
}
void use_read(int fd)
{
#define BUF_LEN 1024
char buf[BUF_LEN];
int len = read(fd, buf, BUF_LEN);
int num_events = len / sizeof(struct inotify_event);
printf("read len = %d, num_events = %d\n", len, num_events);
show_data(buf, len);
show_event((struct inotify_event *)buf, num_events);
}
void use_select(int fd)
{
#define BUF_LEN 1024
char buf[BUF_LEN];
fd_set read_fds;
int rc;
unsigned int bytes_to_read;
/*struct timeval timeout;
timeout.tv_sec = 0;
timeout.tv_usec = 0;*/
FD_ZERO(&read_fds);
FD_SET(fd, &read_fds);
while(1){
rc = select(fd + 1, &read_fds, NULL, NULL, NULL);
if(rc < 0){
printf("select error: %s\n", strerror(errno));
return;
}
rc = ioctl(fd, FIONREAD, &bytes_to_read );
if(rc < 0){
printf("ioctl error: %s\n", strerror(errno));
return;
}
printf("----->current event queue = %u\n", bytes_to_read);
int len = read(fd, buf, BUF_LEN);
int num_events = len / sizeof(struct inotify_event);
printf("read len = %d, num_events = %d\n", len, num_events);
show_event((struct inotify_event *)buf, num_events);
}
}
int main(int argc, char *argv[])
{
int fd;
if(argc != 2){
printf("usage: ./inotify \n");
exit(1);
}
fd = inotify_init();
int wd = inotify_add_watch(fd, argv[1], IN_ALL_EVENTS);
//use_read(fd);
use_select(fd);
inotify_rm_watch(fd, wd);
return 0;
}
运行后，进入你要监听的目录，ls一下，就会收到事件了！！