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
archive_read_open_fd(struct archive * a,int fd,size_t block_size)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
file_read(struct archive * a,void * client_data,const void ** buff)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
file_skip(struct archive * a,void * client_data,int64_t request)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
file_seek(struct archive * a,void * client_data,int64_t request,int whence)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
file_close(struct archive * a,void * client_data)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