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("$FreeBSD$");
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_seek(struct archive *, void *, int64_t request, int);
63static int64_t	file_skip(struct archive *, void *, int64_t request);
64
65int
66archive_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
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	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
131static int64_t
132file_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 */
178static int64_t
179file_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
202static int
203file_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