archive_read_open_fd.c revision 232153 
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/contrib/libarchive/libarchive/archive_read_open_fd.c 232153 2012-02-25 10:58:02Z mm $");
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	 use_lseek;
57	void	*buffer;
58};
59
60static int	file_close(struct archive *, void *);
61static ssize_t	file_read(struct archive *, void *, const void **buff);
62static int64_t	file_skip(struct archive *, void *, int64_t request);
63
64int
65archive_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 = (struct read_fd_data *)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_close_callback(a, file_close);
106	archive_read_set_callback_data(a, mine);
107	return (archive_read_open1(a));
108}
109
110static ssize_t
111file_read(struct archive *a, void *client_data, const void **buff)
112{
113	struct read_fd_data *mine = (struct read_fd_data *)client_data;
114	ssize_t bytes_read;
115
116	*buff = mine->buffer;
117	for (;;) {
118		bytes_read = read(mine->fd, mine->buffer, mine->block_size);
119		if (bytes_read < 0) {
120			if (errno == EINTR)
121				continue;
122			archive_set_error(a, errno, "Error reading fd %d", mine->fd);
123		}
124		return (bytes_read);
125	}
126}
127
128static int64_t
129file_skip(struct archive *a, void *client_data, int64_t request)
130{
131	struct read_fd_data *mine = (struct read_fd_data *)client_data;
132	off_t skip = (off_t)request;
133	off_t old_offset, new_offset;
134	int skip_bits = sizeof(skip) * 8 - 1;  /* off_t is a signed type. */
135
136	if (!mine->use_lseek)
137		return (0);
138
139	/* Reduce a request that would overflow the 'skip' variable. */
140	if (sizeof(request) > sizeof(skip)) {
141		int64_t max_skip =
142		    (((int64_t)1 << (skip_bits - 1)) - 1) * 2 + 1;
143		if (request > max_skip)
144			skip = max_skip;
145	}
146
147	/* Reduce request to the next smallest multiple of block_size */
148	request = (request / mine->block_size) * mine->block_size;
149	if (request == 0)
150		return (0);
151
152	if (((old_offset = lseek(mine->fd, 0, SEEK_CUR)) >= 0) &&
153	    ((new_offset = lseek(mine->fd, skip, SEEK_CUR)) >= 0))
154		return (new_offset - old_offset);
155
156	/* If seek failed once, it will probably fail again. */
157	mine->use_lseek = 0;
158
159	/* Let libarchive recover with read+discard. */
160	if (errno == ESPIPE)
161		return (0);
162
163	/*
164	 * There's been an error other than ESPIPE. This is most
165	 * likely caused by a programmer error (too large request)
166	 * or a corrupted archive file.
167	 */
168	archive_set_error(a, errno, "Error seeking");
169	return (-1);
170}
171
172static int
173file_close(struct archive *a, void *client_data)
174{
175	struct read_fd_data *mine = (struct read_fd_data *)client_data;
176
177	(void)a; /* UNUSED */
178	free(mine->buffer);
179	free(mine);
180	return (ARCHIVE_OK);
181}
182