1/*- 2 * Copyright (c) 2003-2007 Tim Kientzle 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT, 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26#include "archive_platform.h" 27__FBSDID("$FreeBSD: head/lib/libarchive/archive_read_open_fd.c 201103 2009-12-28 03:13:49Z kientzle $"); 28 29#ifdef HAVE_SYS_STAT_H 30#include <sys/stat.h> 31#endif 32#ifdef HAVE_ERRNO_H 33#include <errno.h> 34#endif 35#ifdef HAVE_FCNTL_H 36#include <fcntl.h> 37#endif 38#ifdef HAVE_IO_H 39#include <io.h> 40#endif 41#ifdef HAVE_STDLIB_H 42#include <stdlib.h> 43#endif 44#ifdef HAVE_STRING_H 45#include <string.h> 46#endif 47#ifdef HAVE_UNISTD_H 48#include <unistd.h> 49#endif 50 51#include "archive.h" 52 53struct read_fd_data { 54 int fd; 55 size_t block_size; 56 char can_skip; 57 void *buffer; 58}; 59 60static int file_close(struct archive *, void *); 61static ssize_t file_read(struct archive *, void *, const void **buff); 62#if ARCHIVE_API_VERSION < 2 63static ssize_t file_skip(struct archive *, void *, size_t request); 64#else 65static off_t file_skip(struct archive *, void *, off_t request); 66#endif 67 68int 69archive_read_open_fd(struct archive *a, int fd, size_t block_size) 70{ 71 struct stat st; 72 struct read_fd_data *mine; 73 void *b; 74 75 archive_clear_error(a); 76 if (fstat(fd, &st) != 0) { 77 archive_set_error(a, errno, "Can't stat fd %d", fd); 78 return (ARCHIVE_FATAL); 79 } 80 81 mine = (struct read_fd_data *)malloc(sizeof(*mine)); 82 b = malloc(block_size); 83 if (mine == NULL || b == NULL) { 84 archive_set_error(a, ENOMEM, "No memory"); 85 free(mine); 86 free(b); 87 return (ARCHIVE_FATAL); 88 } 89 mine->block_size = block_size; 90 mine->buffer = b; 91 mine->fd = fd; 92 /* 93 * Skip support is a performance optimization for anything 94 * that supports lseek(). On FreeBSD, only regular files and 95 * raw disk devices support lseek() and there's no portable 96 * way to determine if a device is a raw disk device, so we 97 * only enable this optimization for regular files. 98 */ 99 if (S_ISREG(st.st_mode)) { 100 archive_read_extract_set_skip_file(a, st.st_dev, st.st_ino); 101 mine->can_skip = 1; 102 } else 103 mine->can_skip = 0; 104#if defined(__CYGWIN__) || defined(_WIN32) 105 setmode(mine->fd, O_BINARY); 106#endif 107 108 return (archive_read_open2(a, mine, 109 NULL, file_read, file_skip, file_close)); 110} 111 112static ssize_t 113file_read(struct archive *a, void *client_data, const void **buff) 114{ 115 struct read_fd_data *mine = (struct read_fd_data *)client_data; 116 ssize_t bytes_read; 117 118 *buff = mine->buffer; 119 bytes_read = read(mine->fd, mine->buffer, mine->block_size); 120 if (bytes_read < 0) { 121 archive_set_error(a, errno, "Error reading fd %d", mine->fd); 122 } 123 return (bytes_read); 124} 125 126#if ARCHIVE_API_VERSION < 2 127static ssize_t 128file_skip(struct archive *a, void *client_data, size_t request) 129#else 130static off_t 131file_skip(struct archive *a, void *client_data, off_t request) 132#endif 133{ 134 struct read_fd_data *mine = (struct read_fd_data *)client_data; 135 off_t old_offset, new_offset; 136 137 if (!mine->can_skip) 138 return (0); 139 140 /* Reduce request to the next smallest multiple of block_size */ 141 request = (request / mine->block_size) * mine->block_size; 142 if (request == 0) 143 return (0); 144 145 /* 146 * Hurray for lazy evaluation: if the first lseek fails, the second 147 * one will not be executed. 148 */ 149 if (((old_offset = lseek(mine->fd, 0, SEEK_CUR)) < 0) || 150 ((new_offset = lseek(mine->fd, request, SEEK_CUR)) < 0)) 151 { 152 /* If seek failed once, it will probably fail again. */ 153 mine->can_skip = 0; 154 155 if (errno == ESPIPE) 156 { 157 /* 158 * Failure to lseek() can be caused by the file 159 * descriptor pointing to a pipe, socket or FIFO. 160 * Return 0 here, so the compression layer will use 161 * read()s instead to advance the file descriptor. 162 * It's slower of course, but works as well. 163 */ 164 return (0); 165 } 166 /* 167 * There's been an error other than ESPIPE. This is most 168 * likely caused by a programmer error (too large request) 169 * or a corrupted archive file. 170 */ 171 archive_set_error(a, errno, "Error seeking"); 172 return (-1); 173 } 174 return (new_offset - old_offset); 175} 176 177static int 178file_close(struct archive *a, void *client_data) 179{ 180 struct read_fd_data *mine = (struct read_fd_data *)client_data; 181 182 (void)a; /* UNUSED */ 183 free(mine->buffer); 184 free(mine); 185 return (ARCHIVE_OK); 186} 187