CODEWITHSUNDEEP
c++linuxfilesystems
rex
rex

Reputation: 31

select method fails when IN_DELETE event of inotify occurs

I am trying to monitor a directory recursively on Linux using inotify. I am using select method in my application to monitor directory changes. I get notification for all the events except for delete. When ever i delete a directory, using rm command, my select method fails.

I get the following error "invalid or incomplete multibyte or wide character"

How can i solve this problem.

Thanks for the reply

fd  = inotify_init();

struct timeval time;
fd_set rfds;
int ret;

/* timeout after five seconds */
time.tv_sec = 5;
time.tv_usec = 0;

/* zero-out the fd_set */
FD_ZERO (&rfds);

/*
 * add the inotify fd to the fd_set -- of course,
 * your application will probably want to add
 * other file descriptors here, too
 */
FD_SET (fd, &rfds);

ret = select (fd + 1, &rfds, NULL, NULL, &time);
if (ret < 0)
        perror ("select");
else if (!ret)
        /* timed out! */
else if (FD_ISSET (fd, &rfds)
        /* inotify events are available! */
   {
       // inotify events are available
    len = read(fd, buf, EVENT_BUF_LEN);
    if(len <= 0)
    {
        qDebug()<<"Error : read failed..";
        perror("read : ");
    }

    while(i < len)
    {
        struct inotify_event *event;
        event = (struct inotify_event *) &buf[i];

        eventNotification(event);
        i += EVENT_SIZE + event->len;
        count++;
    }
  }

  void eventNotification (struct inotify_event *event)
  {
      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.\n", event->name );
     }
    }
   }
  }

Upvotes: 0

Views: 274

Answers (1)

rex
rex

Reputation: 31

Found the problem. When I deleted a directory which has sub-directories in it, IN_DELETE_SELF event was also received along with IN_DELETE event and i was closing the fd of the directory that i was monitoring, in IN_DELETE_SELF event. So now when select was called again could not find the fd and gave me that error.

Upvotes: 1

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