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 53 struct read_fd_data { 54 int fd; 55 size_t block_size; 56 char use_lseek; 57 void *buffer; 58 }; 59 60 static int file_close(struct archive *, void *); 61 static ssize_t file_read(struct archive *, void *, const void **buff); 62 static int64_t file_seek(struct archive *, void *, int64_t request, int); 63 static int64_t file_skip(struct archive *, void *, int64_t request); 64 65 int 66 archive_read_open_fd(struct archive *a, int fd, size_t block_size) 67 { 68 struct stat st; 69 struct read_fd_data *mine; 70 void *b; 71 72 archive_clear_error(a); 73 if (fstat(fd, &st) != 0) { 74 archive_set_error(a, errno, "Can't stat fd %d", fd); 75 return (ARCHIVE_FATAL); 76 } 77 78 mine = (struct read_fd_data *)calloc(1, sizeof(*mine)); 79 b = malloc(block_size); 80 if (mine == NULL || b == NULL) { 81 archive_set_error(a, ENOMEM, "No memory"); 82 free(mine); 83 free(b); 84 return (ARCHIVE_FATAL); 85 } 86 mine->block_size = block_size; 87 mine->buffer = b; 88 mine->fd = fd; 89 /* 90 * Skip support is a performance optimization for anything 91 * that supports lseek(). On FreeBSD, only regular files and 92 * raw disk devices support lseek() and there's no portable 93 * way to determine if a device is a raw disk device, so we 94 * only enable this optimization for regular files. 95 */ 96 if (S_ISREG(st.st_mode)) { 97 archive_read_extract_set_skip_file(a, st.st_dev, st.st_ino); 98 mine->use_lseek = 1; 99 } 100 #if defined(__CYGWIN__) || defined(_WIN32) 101 setmode(mine->fd, O_BINARY); 102 #endif 103 104 archive_read_set_read_callback(a, file_read); 105 archive_read_set_skip_callback(a, file_skip); 106 archive_read_set_seek_callback(a, file_seek); 107 archive_read_set_close_callback(a, file_close); 108 archive_read_set_callback_data(a, mine); 109 return (archive_read_open1(a)); 110 } 111 112 static ssize_t 113 file_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 for (;;) { 120 bytes_read = read(mine->fd, mine->buffer, mine->block_size); 121 if (bytes_read < 0) { 122 if (errno == EINTR) 123 continue; 124 archive_set_error(a, errno, "Error reading fd %d", 125 mine->fd); 126 } 127 return (bytes_read); 128 } 129 } 130 131 static int64_t 132 file_skip(struct archive *a, void *client_data, int64_t request) 133 { 134 struct read_fd_data *mine = (struct read_fd_data *)client_data; 135 int64_t skip = request; 136 int64_t old_offset, new_offset; 137 int skip_bits = sizeof(skip) * 8 - 1; /* off_t is a signed type. */ 138 139 if (!mine->use_lseek) 140 return (0); 141 142 /* Reduce a request that would overflow the 'skip' variable. */ 143 if (sizeof(request) > sizeof(skip)) { 144 int64_t max_skip = 145 (((int64_t)1 << (skip_bits - 1)) - 1) * 2 + 1; 146 if (request > max_skip) 147 skip = max_skip; 148 } 149 150 /* Reduce request to the next smallest multiple of block_size */ 151 request = (request / mine->block_size) * mine->block_size; 152 if (request == 0) 153 return (0); 154 155 if (((old_offset = lseek(mine->fd, 0, SEEK_CUR)) >= 0) && 156 ((new_offset = lseek(mine->fd, skip, SEEK_CUR)) >= 0)) 157 return (new_offset - old_offset); 158 159 /* If seek failed once, it will probably fail again. */ 160 mine->use_lseek = 0; 161 162 /* Let libarchive recover with read+discard. */ 163 if (errno == ESPIPE) 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 } 174 175 /* 176 * TODO: Store the offset and use it in the read callback. 177 */ 178 static int64_t 179 file_seek(struct archive *a, void *client_data, int64_t request, int whence) 180 { 181 struct read_fd_data *mine = (struct read_fd_data *)client_data; 182 int64_t r; 183 184 /* We use off_t here because lseek() is declared that way. */ 185 /* See above for notes about when off_t is less than 64 bits. */ 186 r = lseek(mine->fd, request, whence); 187 if (r >= 0) 188 return r; 189 190 if (errno == ESPIPE) { 191 archive_set_error(a, errno, 192 "A file descriptor(%d) is not seekable(PIPE)", mine->fd); 193 return (ARCHIVE_FAILED); 194 } else { 195 /* If the input is corrupted or truncated, fail. */ 196 archive_set_error(a, errno, 197 "Error seeking in a file descriptor(%d)", mine->fd); 198 return (ARCHIVE_FATAL); 199 } 200 } 201 202 static int 203 file_close(struct archive *a, void *client_data) 204 { 205 struct read_fd_data *mine = (struct read_fd_data *)client_data; 206 207 (void)a; /* UNUSED */ 208 free(mine->buffer); 209 free(mine); 210 return (ARCHIVE_OK); 211 } 212