/* seek.c - use glfs_lseek() to find holes in a file
 *
 * Author: Niels de Vos <ndevos@redhat.com>
 */

/* needed for SEEK_HOLE/SEEK_DATA */
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif

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

#include <glusterfs/api/glfs.h>
#include <glusterfs/api/glfs-handles.h>

int
main(int argc, char **argv)
{
    glfs_t *fs = NULL;
    int ret = 0;
    glfs_fd_t *fd = NULL;
    char *filename = NULL;
    char *volname = NULL;
    char *hostname = NULL;
    struct stat st = {
        0,
    };
    off_t hole_start = 0;
    off_t hole_end = 0;

    if (argc != 4) {
        fprintf(stderr, "Invalid argument, use %s <hostname> <vol> <file>\n",
                argv[0]);
        exit(1);
    }

    hostname = argv[1];
    volname = argv[2];
    filename = argv[3];

    fs = glfs_new(volname);
    if (!fs) {
        perror("glfs_new() returned NULL");
        return 1;
    }

    if (glfs_set_volfile_server(fs, "tcp", hostname, 24007)) {
        perror("glfs_set_volfile_server");
        return 1;
    }

    if (glfs_init(fs)) {
        perror("glfs_init");
        return 1;
    }

    fd = glfs_open(fs, filename, O_RDONLY);
    if (fd <= 0) {
        perror("glfs_open");
        return 1;
    }

    if (glfs_fstat(fd, &st)) {
        perror("glfs_fstat");
        return 1;
    }

    while (hole_end < st.st_size) {
        hole_start = glfs_lseek(fd, hole_end, SEEK_HOLE);
        if (hole_start == -1 && errno == ENXIO)
            /* no more holes */
            break;
        if (hole_start == -1) {
            perror("no more holes");
            break;
        }

        hole_end = glfs_lseek(fd, hole_start, SEEK_DATA);
        if (hole_end == -1 && errno == ENXIO) {
            /* no more data */
            break;
        }

        printf("HOLE found: %ld - %ld%s\n", hole_start, hole_end,
               (hole_end == st.st_size) ? " (EOF)" : "");
    }

    glfs_close(fd);

    if (fs) {
        glfs_fini(fs);
    }

    return ret;
}