/*-

 * Copyright (c) 2003-2007 Tim Kientzle

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#include "archive_platform.h"

__FBSDID("$FreeBSD: head/lib/libarchive/archive_read_open_fd.c 201103 2009-12-28 03:13:49Z kientzle $");

#ifdef HAVE_SYS_STAT_H

#include <sys/stat.h>

#endif

#ifdef HAVE_ERRNO_H

#include <errno.h>

#endif

#ifdef HAVE_FCNTL_H

#include <fcntl.h>

#endif

#ifdef HAVE_IO_H

#include <io.h>

#endif

#ifdef HAVE_STDLIB_H

#include <stdlib.h>

#endif

#ifdef HAVE_STRING_H

#include <string.h>

#endif

#ifdef HAVE_UNISTD_H

#include <unistd.h>

#endif

#include "archive.h"

struct read_fd_data {

	int	 fd;

	size_t	 block_size;

	char	 use_lseek;

	void	*buffer;

};

static int	file_close(struct archive *, void *);

static ssize_t	file_read(struct archive *, void *, const void **buff);

static int64_t	file_seek(struct archive *, void *, int64_t request, int);

static int64_t	file_skip(struct archive *, void *, int64_t request);

int

archive_read_open_fd(struct archive *a, int fd, size_t block_size)

{

	struct stat st;

	struct read_fd_data *mine;

	void *b;

	archive_clear_error(a);

	if (fstat(fd, &st) != 0) {

		archive_set_error(a, errno, "Can't stat fd %d", fd);

		return (ARCHIVE_FATAL);

	}

	mine = (struct read_fd_data *)calloc(1, sizeof(*mine));

	b = malloc(block_size);

	if (mine == NULL || b == NULL) {

		archive_set_error(a, ENOMEM, "No memory");

		free(mine);

		free(b);

		return (ARCHIVE_FATAL);

	}

	mine->block_size = block_size;

	mine->buffer = b;

	mine->fd = fd;

	/*

	 * Skip support is a performance optimization for anything

	 * that supports lseek().  On FreeBSD, only regular files and

	 * raw disk devices support lseek() and there's no portable

	 * way to determine if a device is a raw disk device, so we

	 * only enable this optimization for regular files.

	 */

	if (S_ISREG(st.st_mode)) {

		archive_read_extract_set_skip_file(a, st.st_dev, st.st_ino);

		mine->use_lseek = 1;

	}

#if defined(__CYGWIN__) || defined(_WIN32)

	setmode(mine->fd, O_BINARY);

#endif

	archive_read_set_read_callback(a, file_read);

	archive_read_set_skip_callback(a, file_skip);

	archive_read_set_seek_callback(a, file_seek);

	archive_read_set_close_callback(a, file_close);

	archive_read_set_callback_data(a, mine);

	return (archive_read_open1(a));

}

static ssize_t

file_read(struct archive *a, void *client_data, const void **buff)

{

	struct read_fd_data *mine = (struct read_fd_data *)client_data;

	ssize_t bytes_read;

	*buff = mine->buffer;

	for (;;) {

		bytes_read = read(mine->fd, mine->buffer, mine->block_size);

		if (bytes_read < 0) {

			if (errno == EINTR)

				continue;

			archive_set_error(a, errno, "Error reading fd %d",

			    mine->fd);

		}

		return (bytes_read);

	}

}

static int64_t

file_skip(struct archive *a, void *client_data, int64_t request)

{

	struct read_fd_data *mine = (struct read_fd_data *)client_data;

	int64_t skip = request;

	int64_t old_offset, new_offset;

	int skip_bits = sizeof(skip) * 8 - 1;  /* off_t is a signed type. */

	if (!mine->use_lseek)

		return (0);

	/* Reduce a request that would overflow the 'skip' variable. */

	if (sizeof(request) > sizeof(skip)) {

		int64_t max_skip =

		    (((int64_t)1 << (skip_bits - 1)) - 1) * 2 + 1;

		if (request > max_skip)

			skip = max_skip;

	}

	/* Reduce request to the next smallest multiple of block_size */

	request = (request / mine->block_size) * mine->block_size;

	if (request == 0)

		return (0);

	if (((old_offset = lseek(mine->fd, 0, SEEK_CUR)) >= 0) &&

	    ((new_offset = lseek(mine->fd, skip, SEEK_CUR)) >= 0))

		return (new_offset - old_offset);

	/* If seek failed once, it will probably fail again. */

	mine->use_lseek = 0;

	/* Let libarchive recover with read+discard. */

	if (errno == ESPIPE)

		return (0);

	/*

	 * There's been an error other than ESPIPE. This is most

	 * likely caused by a programmer error (too large request)

	 * or a corrupted archive file.

	 */

	archive_set_error(a, errno, "Error seeking");

	return (-1);

}

/*

 * TODO: Store the offset and use it in the read callback.

 */

static int64_t

file_seek(struct archive *a, void *client_data, int64_t request, int whence)

{

	struct read_fd_data *mine = (struct read_fd_data *)client_data;

	int64_t r;

	/* We use off_t here because lseek() is declared that way. */

	/* See above for notes about when off_t is less than 64 bits. */

	r = lseek(mine->fd, request, whence);

	if (r >= 0)

		return r;

	if (errno == ESPIPE) {

		archive_set_error(a, errno,

		    "A file descriptor(%d) is not seekable(PIPE)", mine->fd);

		return (ARCHIVE_FAILED);

	} else {

		/* If the input is corrupted or truncated, fail. */

		archive_set_error(a, errno,

		    "Error seeking in a file descriptor(%d)", mine->fd);

		return (ARCHIVE_FATAL);

	}

}

static int

file_close(struct archive *a, void *client_data)

{

	struct read_fd_data *mine = (struct read_fd_data *)client_data;

	(void)a; /* UNUSED */

	free(mine->buffer);

	free(mine);

	return (ARCHIVE_OK);

}