1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2021 Peter Holm <pho@FreeBSD.org> 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/param.h> 29 #include <sys/stat.h> 30 31 #include <err.h> 32 #include <errno.h> 33 #include <fcntl.h> 34 #include <stdio.h> 35 #include <stdlib.h> 36 #include <unistd.h> 37 38 int 39 main(int argc, char *argv[]) 40 { 41 struct stat st; 42 off_t data, hole, pos; 43 long mx; 44 int fd, n; 45 char *name; 46 47 if (argc != 2) { 48 fprintf(stderr, "Usage: %s <file>\n", argv[0]); 49 exit(1); 50 } 51 52 name = argv[1]; 53 if ((fd = open(name, O_RDONLY)) == -1) 54 err(1, "open(%s)", name); 55 if (fstat(fd, &st)) 56 err(1, "fstat()"); 57 if ((mx = fpathconf(fd, _PC_MIN_HOLE_SIZE)) == -1) 58 err(1, "fpathconf()"); 59 fprintf(stderr, "file \"%s\" size = %jd, _PC_MIN_HOLE_SIZE = %ld\n", 60 name, (intmax_t)st.st_size, mx); 61 n = 1; 62 pos = 0; 63 while (pos < st.st_size) { 64 if ((hole = lseek(fd, pos, SEEK_HOLE)) == -1) 65 err(1, "lseek(SEEK_HOLE)"); 66 if ((data = lseek(fd, hole, SEEK_DATA)) == -1) { 67 if (errno == ENXIO) { 68 if (hole == st.st_size) 69 break; 70 fprintf(stderr, 71 "No data after hole @ %jd\n", 72 (intmax_t)hole); 73 break; 74 } 75 err(1, "lseek(SEEK_DATA)"); 76 } 77 pos = data; 78 printf("hole #%d @ %jd (0x%jx), size=%jd (0x%jx)\n", 79 n, (intmax_t)hole, (intmax_t)hole, (intmax_t)(data - hole), 80 (intmax_t)(data - hole)); 81 n++; 82 } 83 close(fd); 84 if (hole != st.st_size) 85 errx(1, "No implicit hole at EOF"); 86 } 87