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
28 #ifdef HAVE_SYS_STAT_H
29 #include <sys/stat.h>
30 #endif
31 #ifdef HAVE_ERRNO_H
32 #include <errno.h>
33 #endif
34 #ifdef HAVE_FCNTL_H
35 #include <fcntl.h>
36 #endif
37 #ifdef HAVE_IO_H
38 #include <io.h>
39 #endif
40 #ifdef HAVE_STDLIB_H
41 #include <stdlib.h>
42 #endif
43 #ifdef HAVE_STRING_H
44 #include <string.h>
45 #endif
46 #ifdef HAVE_UNISTD_H
47 #include <unistd.h>
48 #endif
49
50 #include "archive.h"
51
52 struct read_fd_data {
53 int fd;
54 size_t block_size;
55 char use_lseek;
56 void *buffer;
57 };
58
59 static int file_close(struct archive *, void *);
60 static ssize_t file_read(struct archive *, void *, const void **buff);
61 static int64_t file_seek(struct archive *, void *, int64_t request, int);
62 static int64_t file_skip(struct archive *, void *, int64_t request);
63
64 int
archive_read_open_fd(struct archive * a,int fd,size_t block_size)65 archive_read_open_fd(struct archive *a, int fd, size_t block_size)
66 {
67 struct stat st;
68 struct read_fd_data *mine;
69 void *b;
70
71 archive_clear_error(a);
72 if (fstat(fd, &st) != 0) {
73 archive_set_error(a, errno, "Can't stat fd %d", fd);
74 return (ARCHIVE_FATAL);
75 }
76
77 mine = calloc(1, sizeof(*mine));
78 b = malloc(block_size);
79 if (mine == NULL || b == NULL) {
80 archive_set_error(a, ENOMEM, "No memory");
81 free(mine);
82 free(b);
83 return (ARCHIVE_FATAL);
84 }
85 mine->block_size = block_size;
86 mine->buffer = b;
87 mine->fd = fd;
88 /*
89 * Skip support is a performance optimization for anything
90 * that supports lseek(). On FreeBSD, only regular files and
91 * raw disk devices support lseek() and there's no portable
92 * way to determine if a device is a raw disk device, so we
93 * only enable this optimization for regular files.
94 */
95 if (S_ISREG(st.st_mode)) {
96 archive_read_extract_set_skip_file(a, st.st_dev, st.st_ino);
97 mine->use_lseek = 1;
98 }
99 #if defined(__CYGWIN__) || defined(_WIN32)
100 setmode(mine->fd, O_BINARY);
101 #endif
102
103 archive_read_set_read_callback(a, file_read);
104 archive_read_set_skip_callback(a, file_skip);
105 archive_read_set_seek_callback(a, file_seek);
106 archive_read_set_close_callback(a, file_close);
107 archive_read_set_callback_data(a, mine);
108 return (archive_read_open1(a));
109 }
110
111 static ssize_t
file_read(struct archive * a,void * client_data,const void ** buff)112 file_read(struct archive *a, void *client_data, const void **buff)
113 {
114 struct read_fd_data *mine = (struct read_fd_data *)client_data;
115 ssize_t bytes_read;
116
117 *buff = mine->buffer;
118 for (;;) {
119 bytes_read = read(mine->fd, mine->buffer, mine->block_size);
120 if (bytes_read < 0) {
121 if (errno == EINTR)
122 continue;
123 archive_set_error(a, errno, "Error reading fd %d",
124 mine->fd);
125 }
126 return (bytes_read);
127 }
128 }
129
130 static int64_t
file_skip(struct archive * a,void * client_data,int64_t request)131 file_skip(struct archive *a, void *client_data, int64_t request)
132 {
133 struct read_fd_data *mine = (struct read_fd_data *)client_data;
134 int64_t skip = request;
135 int64_t old_offset, new_offset;
136 int skip_bits = sizeof(skip) * 8 - 1; /* off_t is a signed type. */
137
138 if (!mine->use_lseek)
139 return (0);
140
141 /* Reduce a request that would overflow the 'skip' variable. */
142 if (sizeof(request) > sizeof(skip)) {
143 int64_t max_skip =
144 (((int64_t)1 << (skip_bits - 1)) - 1) * 2 + 1;
145 if (request > max_skip)
146 skip = max_skip;
147 }
148
149 /* Reduce request to the next smallest multiple of block_size */
150 request = (request / mine->block_size) * mine->block_size;
151 if (request == 0)
152 return (0);
153
154 if (((old_offset = lseek(mine->fd, 0, SEEK_CUR)) >= 0) &&
155 ((new_offset = lseek(mine->fd, skip, SEEK_CUR)) >= 0))
156 return (new_offset - old_offset);
157
158 /* If seek failed once, it will probably fail again. */
159 mine->use_lseek = 0;
160
161 /* Let libarchive recover with read+discard. */
162 if (errno == ESPIPE)
163 return (0);
164
165 /*
166 * There's been an error other than ESPIPE. This is most
167 * likely caused by a programmer error (too large request)
168 * or a corrupted archive file.
169 */
170 archive_set_error(a, errno, "Error seeking");
171 return (-1);
172 }
173
174 /*
175 * TODO: Store the offset and use it in the read callback.
176 */
177 static int64_t
file_seek(struct archive * a,void * client_data,int64_t request,int whence)178 file_seek(struct archive *a, void *client_data, int64_t request, int whence)
179 {
180 struct read_fd_data *mine = (struct read_fd_data *)client_data;
181 int64_t r;
182
183 /* We use off_t here because lseek() is declared that way. */
184 /* See above for notes about when off_t is less than 64 bits. */
185 r = lseek(mine->fd, request, whence);
186 if (r >= 0)
187 return r;
188
189 if (errno == ESPIPE) {
190 archive_set_error(a, errno,
191 "A file descriptor(%d) is not seekable(PIPE)", mine->fd);
192 return (ARCHIVE_FAILED);
193 } else {
194 /* If the input is corrupted or truncated, fail. */
195 archive_set_error(a, errno,
196 "Error seeking in a file descriptor(%d)", mine->fd);
197 return (ARCHIVE_FATAL);
198 }
199 }
200
201 static int
file_close(struct archive * a,void * client_data)202 file_close(struct archive *a, void *client_data)
203 {
204 struct read_fd_data *mine = (struct read_fd_data *)client_data;
205
206 (void)a; /* UNUSED */
207 free(mine->buffer);
208 free(mine);
209 return (ARCHIVE_OK);
210 }
211