*/
/*****************************************************************************
*
- * File inotufy_monitor.c:
+ * File inotify_monitor.c:
*
- * An example for shared memory use: monitor a directory status,
- * saving data in a shared memory segment
+ * An example of the inotify interface: use inotify to watch the
+ * status of a directory or a file
*
* Author: S. Piccardi Jul. 2007
*
*****************************************************************************/
#include <sys/types.h>
-#include <sys/inotify.h>
-#include <stdlib.h> /* C standard library */
-#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/inotify.h> /* Linux inotify interface */
+#include <sys/epoll.h> /* Linux epoll interface */
+#include <stdlib.h> /* C standard library */
+#include <unistd.h> /* Unix standard library */
#include <errno.h> /* error definitions and routines */
#include <stdio.h> /* standard I/O library */
#include <string.h> /* string functions */
+#include <fcntl.h> /* fcntl function */
+#include <sys/ioctl.h> /* ioctl function */
#include "macros.h"
/* Help printing routine */
void usage(void);
+void printevent(unsigned int mask);
int main(int argc, char *argv[])
{
- int i;
- int fd;
+ int i, size, nread;
+ int fd, wd, epfd;
+ char buffer[1024 + sizeof(struct inotify_event)];
unsigned int mask=0;
+ struct inotify_event * event;
+ struct epoll_event epev;
/*
* Input section: decode command line parameters
* Use getopt function
*/
opterr = 0; /* don't want writing to stderr */
- while ( (i = getopt(argc, argv, "hrwcda")) != -1) {
+ while ((i = getopt(argc, argv, "hrwcda")) != -1) {
switch (i) {
/*
* Handling options
*/
- case 'h': /* help option */
+ case 'h': /* help option */
printf("Wrong -h option use\n");
usage();
- return -1;
- break;
- case 'r': /* read access */
+ case 'r': /* read access */
mask |= IN_ACCESS;
break;
- case 'w': /* write access */
+ case 'w': /* write access */
mask |= IN_MODIFY;
break;
- case 'c': /* creation */
+ case 'c': /* creation */
mask |= IN_CREATE;
break;
- case 'd': /* deletion */
+ case 'd': /* deletion */
mask |= IN_DELETE;
break;
- case 'a': /* all events */
+ case 'a': /* all events */
mask |= IN_ALL_EVENTS;
break;
- case '?': /* unrecognized options */
+ case '?': /* unrecognized options */
printf("Unrecognized options -%c\n",optopt);
usage();
- default: /* should not reached */
+ default: /* should not reached */
usage();
}
}
* Main code beginning
*
* ***********************************************************/
- if ((argc - optind) != 1) { /* There must be remaing parameters */
+ if ((argc - optind) != 1) { /* There must be one argument */
printf("Wrong number of arguments %d\n", argc - optind);
usage();
}
- /* initalialize */
- fd = inotify_init ();
- if (fd < 0)
+ epfd = epoll_create(5); /* initialize epoll */
+ if (epfd < 0) {
+ perror("Failing on epoll_create");
+ exit(-1);
+ }
+ fd = inotify_init(); /* initialize inotify */
+ if (fd < 0) {
perror("Failing on inotify_init");
-
- /* add watch */
- if (inotify_add_watch(fd, argv[1], mask) != 0) {
- printf("Failing to add watched file %s; %s\n",
- argv[1], strerror(errno));
exit(-1);
}
-
+ if (fcntl(fd, F_SETFL, O_NONBLOCK)) { /* no blocking I/O on inotify */
+ perror("Cannot set noblocking I/O on inotify fd");
+ exit(-1);
+ }
+ wd = inotify_add_watch(fd, argv[optind], mask); /* add watch */
+ if (wd <= 0) {
+ printf("Failing to add watched file %s, mask %i; %s\n",
+ argv[optind], mask, strerror(errno));
+ exit(-1);
+ }
+ epev.data.fd = fd; /* add inotify fd to epoll */
+ epev.events = EPOLLIN;
+ if (epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &epev)) {
+ perror("Failing on epoll_ctl");
+ exit(-1);
+ }
+ /*
+ * Main Loop: read events and print them
+ */
+ while (1) {
+ if (epoll_wait(epfd, &epev, 1, -1) < 0) {
+ perror("error on epoll_wait");
+ exit(-1);
+ }
+ if (epev.data.fd != fd)
+ printf("something wrong, epoll activity on %i instead of %i\n",
+ epev.data.fd, fd);
+
+ if (ioctl(fd, FIONREAD, &size)) {
+ perror("error on getting inotify event size");
+ exit(-1);
+ }
+ if (size > sizeof(buffer)) {
+ printf("Too many %i data to read, something wrong\n", size);
+ exit(-1);
+ }
+ i = 0;
+ while (i < size) {
+ nread = read(fd, buffer, size);
+ if (nread < 0) {
+ perror("error reading inotify data");
+ exit(1);
+ }
+ i += nread;
+ event = (struct inotify_event *) buffer;
+ if (wd != event->wd) {
+ printf("Getting different watch descriptor, %i and %i\n",
+ wd, event->wd);
+ } else {
+ printf("Observed event on %s\n", argv[optind-1+event->wd]);
+ if (event->name != NULL)
+ printf("On file %s\n", event->name);
+ printevent(event->mask);
+ }
+ }
+ }
return 0;
-
}
/*
* routine to print usage info and exit
void usage(void) {
printf("Program inotify_monitor: monitor file changes \n");
printf("Usage:\n");
- printf(" inotify_monitor [-h] -rwcd dirname/filename \n");
+ printf(" inotify_monitor [-h] -rwcd dirname/filename dir/file ... \n");
printf(" -h print this help\n");
printf(" -w watch write\n");
printf(" -r watch read\n");
printf(" -a watch all\n");
exit(1);
}
+
+void printevent(unsigned int mask) {
+ int i;
+ int val;
+ char * inotify_event[] = {
+ "IN_ACCESS",
+ "IN_MODIFY",
+ "IN_ATTRIB",
+ "IN_CLOSE_WRITE",
+ "IN_CLOSE_NOWRITE",
+ "IN_OPEN",
+ "IN_MOVED_FROM",
+ "IN_MOVED_TO",
+ "IN_CREATE",
+ "IN_DELETE",
+ "IN_DELETE_SELF",
+ "IN_MOVE_SELF",
+ "ERROR!!!",
+ "IN_UNMOUNT",
+ "IN_Q_OVERFLOW",
+ "IN_IGNORED"
+ };
+
+ val=1;
+ for (i=0; i<16; i++) {
+ if (mask & val)
+ printf("%s, ", inotify_event[i]);
+ val = val << 1;
+ }
+ printf("\n");
+}