autohold.c

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

#define EVENT_SIZE 	(sizeof (struct inotify_event))
#define EVENT_BUF_LEN	(1024 * (EVENT_SIZE + 16))
int main( )
{
	int length, i = 0;
	int fd;
	int wd;
	char buffer[EVENT_BUF_LEN];

	/*creating the INOTIFY instance*/
	fd = inotify_init();

	/*checking for error*/
	if ( fd < 0 ) {
		perror( "inotify_init" );
	}

	/*adding the “/tmp” directory into watch list. Here, the suggestion is to validate the existence of the directory before adding into monitoring list.*/
	wd = inotify_add_watch( fd, "/dev/ttyUSB0", IN_CREATE | IN_DELETE | IN_MODIFY );

	/*read to determine the event change happens on “/tmp” directory. Actually this read blocks until the change event occurs*/ 

	length = read( fd, buffer, EVENT_BUF_LEN ); 

	/*checking for error*/
	if ( length < 0 ) {
	perror( "read" );
	}  

	/*actually read return the list of change events happens. Here, read the change event one by one and process it accordingly.*/
	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( "New directory %s modded.\n", event->name );
			}
			else {
				printf( "New file %s modded.\n", event->name );
			}
		}
		else if ( event->mask & IN_DELETE ) {
			if ( event->mask & IN_ISDIR ) {
				printf( "Directory %s deleted.\n", event->name );
			}
			else {
				printf( "File %s deleted.\n", event->name );
			}
		}
	}
	i += EVENT_SIZE + event->len;
	}
	/*removing the “/tmp” directory from the watch list.*/
	inotify_rm_watch( fd, wd );
	/*closing the INOTIFY instance*/
	close( fd );

}