#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <sys/inotify.h>

/* Allow for 1024 simultanious events */
#define BUFF_SIZE ((sizeof(struct inotify_event)+FILENAME_MAX)*1024)

/* IN_CREATE, IN_DELETE, IN_DELETE_SELF, 
 * IN_OPEN, IN_CLOSE_WRITE, IN_CLOSE_NOWRITE,
 * IN_ACCESS, IN_MODIFY, IN_ATTRIB,
 * IN_MOVE_SELF, IN_MOVED_FROM, IN_MOVED_TO,
 */
#define MY_MASK (IN_CREATE | IN_DELETE | IN_DELETE_SELF)

static void handle_error(int err)
{
   fprintf (stderr, "Error: %s\n", strerror(err));
}

void get_inotify_event(int fd, const char * target)
{
   ssize_t len, i = 0;
   char action[81+FILENAME_MAX] = {0};
   char buff[BUFF_SIZE] = {0};

   len = read(fd, buff, BUFF_SIZE);
   
   while (i < len) {
      struct inotify_event *pevent = (struct inotify_event *)&buff[i];
      char action[81+FILENAME_MAX] = {0};

      unsigned int mask = pevent->mask & MY_MASK;

      if (!mask)
         goto skip;

      if (pevent->len) 
         strcpy(action, pevent->name);
      else
         strcpy(action, target);
    
/*
      if (mask & IN_ACCESS) 
         strcat(action, " was read");
      if (mask & IN_ATTRIB) 
         strcat(action, " Metadata changed");
      if (mask & IN_MODIFY) 
         strcat(action, " was modified");
*/

/*
      if (mask & IN_OPEN) 
         strcat(action, " was opened");
      if (mask & IN_CLOSE_WRITE) 
         strcat(action, " opened for writing was closed");
      if (mask & IN_CLOSE_NOWRITE) 
         strcat(action, " not opened for writing was closed");
*/

      if (mask & IN_CREATE) 
         strcat(action, " created in watched directory");
      if (mask & IN_DELETE) 
         strcat(action, " deleted from watched directory");
      if (mask & IN_DELETE_SELF) 
         strcat(action, "Watched file/directory was itself deleted");

/*
      if (mask & IN_MOVE_SELF) 
         strcat(action, "Watched file/directory was itself moved");
      if (mask & IN_MOVED_FROM) 
         strcat(action, " moved out of watched directory");
      if (mask & IN_MOVED_TO) 
         strcat(action, " moved into watched directory");
*/
 
      printf("wd=%d mask=%d cookie=%d len=%d dir=%s\n",
              pevent->wd, pevent->mask, pevent->cookie, pevent->len, 
              (pevent->mask & IN_ISDIR)?"yes":"no");

      printf("%s\n", action);
      
 skip:
      i += sizeof(struct inotify_event) + pevent->len;
   }
}

int main(int argc, char *argv[])
{
   char target[FILENAME_MAX];
   int result;
   int fd;
   int wd;   /* watch descriptor */

   if (argc < 2) {
      fprintf(stderr, "Watching the current directory\n");
      strcpy(target, ".");
   }
   else {
      fprintf(stderr, "Watching %s\n", argv[1]);
      strcpy(target, argv[1]);
   }

   fd = inotify_init();
   if (fd < 0) {
      handle_error(errno);
      return 1;
   }
   
   wd = inotify_add_watch(fd, target, IN_ALL_EVENTS);
   if (wd < 0) {
      handle_error(errno);
      return 1;
   }
   
   while (1) {
      get_inotify_event(fd, target);
   }

   return 0;
}