// stolen from here http://www.xypron.de/projects/fanotify-manpages/man7/fanotify.7.html 
// changed from me richard 
// compile with: gcc -o fanotify-waiting fanotify-waiting -lpthread 
//
#define _GNU_SOURCE // for O_LARGEFILE 
#include <fcntl.h> 
#include <limits.h> 
#include <pthread.h> 
#include <signal.h> 
#include <stdio.h> 
#include <stdlib.h>
#include <string.h> 
#include <sys/fanotify.h>

char* verzeichnis = "/install";

//---------------------------------------------------------------- 
static void *run(void *data) {
    char buf[4096], *p;
    int fd,ret;
    const struct fanotify_event_metadata *metadata;
    int len;
    char path[PATH_MAX];
    int path_len;
    struct fanotify_response response;
    if (-1 == (fd = fanotify_init(FAN_CLOEXEC | FAN_CLASS_CONTENT, O_RDONLY | O_LARGEFILE))) {
        perror("Cannot init");
        return NULL;
    }
    if (-1 == (fanotify_mark(fd, FAN_MARK_ADD  , FAN_OPEN | FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD , FAN_NOFD, verzeichnis))) {
        perror("Cannot mark");
        close(fd);
        return NULL;
    }
    while (-1 != (len = read(fd, (void *) &buf, sizeof (buf)))) {
        metadata = (struct fanotify_event_metadata *) buf;
        while (FAN_EVENT_OK(metadata, len)) {
            if (metadata->fd != FAN_NOFD) {
                if (metadata->fd >= 0) {
                    if (metadata->mask & FAN_OPEN) 
			{
                        response.fd = metadata->fd;
                        }
                    sprintf(path, "/proc/self/fd/%d", metadata->fd);
                    path_len = readlink(path, path, sizeof (path) - 1);
                    if (path_len > 0) {
                        path[path_len] = 0x00;
			
			if (strcmp(path,verzeichnis))
			{
			response.response = FAN_DENY;
                        write(fd, &response, sizeof (struct fanotify_response));
			printf("DENY path: %s\t", path);
			}
                    }
                    close(metadata->fd);
                }
                printf("\n");
            }
            metadata = FAN_EVENT_NEXT(metadata, len);
        }
    }
    close(fd);
    return NULL;
}
//---------------------------------------------------------------- 
int main(int argc, char *argv[]) {
    pthread_attr_t attr;
    pthread_t thread;
    void *result;
    if (pthread_attr_init(&attr)) {
        return EXIT_FAILURE;
    }
    if (pthread_create(&thread, &attr, run, NULL)) {
        return EXIT_FAILURE;
    }
    printf("Press any key to terminate\n");
    getchar();
    if (0 != pthread_kill(thread, SIGUSR1)) {
        return EXIT_FAILURE;
    }
    pthread_join(thread, &result);
    return EXIT_SUCCESS;
}

//----------------------------------------------------------------