/**
 *  lseek test
 *
 *  Copyright (C) 2014 NAKAMURA Minoru <nminoru@nminoru.jp>
 *
 *  gcc -Wall -D_GNU_SOURCE  -g seek_hole.c -o seek_hoke
 */
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <assert.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <linux/fs.h>
#include <linux/fiemap.h>


int main(int argc, char **argv)
{
    int           fd;
    off_t         off;
    struct stat   statinfo;

    if (argc != 2) {
        fprintf(stderr, "Syntax: %s filename\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    if ((fd = open(argv[1], O_RDONLY)) < 0) {
        fprintf(stderr, "Cannot open %s\n", argv[1]);
        exit(EXIT_FAILURE);
    }

    if (fstat(fd, &statinfo) < 0) {
        fprintf(stderr, "Cannot stat %s\n", argv[1]);
        close(fd);
        exit(EXIT_FAILURE);
    }

    off = 0;

    while (off < statinfo.st_size) {
        off_t offset1, offset2;
        offset1 = lseek(fd, off, SEEK_HOLE);
        if (offset1 == (off_t) -1)
            goto error;

        offset2 = lseek(fd, offset1, SEEK_DATA);
        if (off == (off_t) -1)
            goto error;

        off = offset2;
    }

error:
    close(fd);

    exit(EXIT_SUCCESS);
}