/*-

 * Copyright (c) 2003-2011 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.

 */

/*

 * This file contains the "essential" portions of the read API, that

 * is, stuff that will probably always be used by any client that

 * actually needs to read an archive.  Optional pieces have been, as

 * far as possible, separated out into separate files to avoid

 * needlessly bloating statically-linked clients.

 */

#include "archive_platform.h"

__FBSDID("$FreeBSD: head/lib/libarchive/archive_read.c 201157 2009-12-29 05:30:23Z kientzle $");

#ifdef HAVE_ERRNO_H

#include <errno.h>

#endif

#include <stdio.h>

#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"

#include "archive_entry.h"

#include "archive_private.h"

#include "archive_read_private.h"

#define minimum(a, b) (a < b ? a : b)

static int	choose_filters(struct archive_read *);

static int	choose_format(struct archive_read *);

static int	close_filters(struct archive_read *);

static struct archive_vtable *archive_read_vtable(void);

static int64_t	_archive_filter_bytes(struct archive *, int);

static int	_archive_filter_code(struct archive *, int);

static const char *_archive_filter_name(struct archive *, int);

static int  _archive_filter_count(struct archive *);

static int	_archive_read_close(struct archive *);

static int	_archive_read_data_block(struct archive *,

		    const void **, size_t *, int64_t *);

static int	_archive_read_free(struct archive *);

static int	_archive_read_next_header(struct archive *,

		    struct archive_entry **);

static int	_archive_read_next_header2(struct archive *,

		    struct archive_entry *);

static int64_t  advance_file_pointer(struct archive_read_filter *, int64_t);

static struct archive_vtable *

archive_read_vtable(void)

{

	static struct archive_vtable av;

	static int inited = 0;

	if (!inited) {

		av.archive_filter_bytes = _archive_filter_bytes;

		av.archive_filter_code = _archive_filter_code;

		av.archive_filter_name = _archive_filter_name;

		av.archive_filter_count = _archive_filter_count;

		av.archive_read_data_block = _archive_read_data_block;

		av.archive_read_next_header = _archive_read_next_header;

		av.archive_read_next_header2 = _archive_read_next_header2;

		av.archive_free = _archive_read_free;

		av.archive_close = _archive_read_close;

		inited = 1;

	}

	return (&av;;

}

/*

 * Allocate, initialize and return a struct archive object.

 */

struct archive *

archive_read_new(void)

{

	struct archive_read *a;

	a = (struct archive_read *)calloc(1, sizeof(*a));

	if (a == NULL)

		return (NULL);

	a->archive.magic = ARCHIVE_READ_MAGIC;

	a->archive.state = ARCHIVE_STATE_NEW;

	a->entry = archive_entry_new2(&a->archive);

	a->archive.vtable = archive_read_vtable();

	a->passphrases.last = &a->passphrases.first;

	return (&a->archive);

}

/*

 * Record the do-not-extract-to file. This belongs in archive_read_extract.c.

 */

void

archive_read_extract_set_skip_file(struct archive *_a, la_int64_t d,

    la_int64_t i)

{

	struct archive_read *a = (struct archive_read *)_a;

	if (ARCHIVE_OK != __archive_check_magic(_a, ARCHIVE_READ_MAGIC,

		ARCHIVE_STATE_ANY, "archive_read_extract_set_skip_file"))

		return;

	a->skip_file_set = 1;

	a->skip_file_dev = d;

	a->skip_file_ino = i;

}

/*

 * Open the archive

 */

int

archive_read_open(struct archive *a, void *client_data,

    archive_open_callback *client_opener, archive_read_callback *client_reader,

    archive_close_callback *client_closer)

{

	/* Old archive_read_open() is just a thin shell around

	 * archive_read_open1. */

	archive_read_set_open_callback(a, client_opener);

	archive_read_set_read_callback(a, client_reader);

	archive_read_set_close_callback(a, client_closer);

	archive_read_set_callback_data(a, client_data);

	return archive_read_open1(a);

}

int

archive_read_open2(struct archive *a, void *client_data,

    archive_open_callback *client_opener,

    archive_read_callback *client_reader,

    archive_skip_callback *client_skipper,

    archive_close_callback *client_closer)

{

	/* Old archive_read_open2() is just a thin shell around

	 * archive_read_open1. */

	archive_read_set_callback_data(a, client_data);

	archive_read_set_open_callback(a, client_opener);

	archive_read_set_read_callback(a, client_reader);

	archive_read_set_skip_callback(a, client_skipper);

	archive_read_set_close_callback(a, client_closer);

	return archive_read_open1(a);

}

static ssize_t

client_read_proxy(struct archive_read_filter *self, const void **buff)

{

	ssize_t r;

	r = (self->archive->client.reader)(&self->archive->archive,

	    self->data, buff);

	return (r);

}

static int64_t

client_skip_proxy(struct archive_read_filter *self, int64_t request)

{

	if (request < 0)

		__archive_errx(1, "Negative skip requested.");

	if (request == 0)

		return 0;

	if (self->archive->client.skipper != NULL) {

		/* Seek requests over 1GiB are broken down into

		 * multiple seeks.  This avoids overflows when the

		 * requests get passed through 32-bit arguments. */

		int64_t skip_limit = (int64_t)1 << 30;

		int64_t total = 0;

		for (;;) {

			int64_t get, ask = request;

			if (ask > skip_limit)

				ask = skip_limit;

			get = (self->archive->client.skipper)

				(&self->archive->archive, self->data, ask);

			total += get;

			if (get == 0 || get == request)

				return (total);

			if (get > request)

				return ARCHIVE_FATAL;

			request -= get;

		}

	} else if (self->archive->client.seeker != NULL

		&& request > 64 * 1024) {

		/* If the client provided a seeker but not a skipper,

		 * we can use the seeker to skip forward.

		 *

		 * Note: This isn't always a good idea.  The client

		 * skipper is allowed to skip by less than requested

		 * if it needs to maintain block alignment.  The

		 * seeker is not allowed to play such games, so using

		 * the seeker here may be a performance loss compared

		 * to just reading and discarding.  That's why we

		 * only do this for skips of over 64k.

		 */

		int64_t before = self->position;

		int64_t after = (self->archive->client.seeker)

		    (&self->archive->archive, self->data, request, SEEK_CUR);

		if (after != before + request)

			return ARCHIVE_FATAL;

		return after - before;

	}

	return 0;

}

static int64_t

client_seek_proxy(struct archive_read_filter *self, int64_t offset, int whence)

{

	/* DO NOT use the skipper here!  If we transparently handled

	 * forward seek here by using the skipper, that will break

	 * other libarchive code that assumes a successful forward

	 * seek means it can also seek backwards.

	 */

	if (self->archive->client.seeker == NULL) {

		archive_set_error(&self->archive->archive, ARCHIVE_ERRNO_MISC,

		    "Current client reader does not support seeking a device");

		return (ARCHIVE_FAILED);

	}

	return (self->archive->client.seeker)(&self->archive->archive,

	    self->data, offset, whence);

}

static int

client_close_proxy(struct archive_read_filter *self)

{

	int r = ARCHIVE_OK, r2;

	unsigned int i;

	if (self->archive->client.closer == NULL)

		return (r);

	for (i = 0; i < self->archive->client.nodes; i++)

	{

		r2 = (self->archive->client.closer)

			((struct archive *)self->archive,

				self->archive->client.dataset[i].data);

		if (r > r2)

			r = r2;

	}

	return (r);

}

static int

client_open_proxy(struct archive_read_filter *self)

{

  int r = ARCHIVE_OK;

	if (self->archive->client.opener != NULL)

		r = (self->archive->client.opener)(

		    (struct archive *)self->archive, self->data);

	return (r);

}

static int

client_switch_proxy(struct archive_read_filter *self, unsigned int iindex)

{

  int r1 = ARCHIVE_OK, r2 = ARCHIVE_OK;

	void *data2 = NULL;

	/* Don't do anything if already in the specified data node */

	if (self->archive->client.cursor == iindex)

		return (ARCHIVE_OK);

	self->archive->client.cursor = iindex;

	data2 = self->archive->client.dataset[self->archive->client.cursor].data;

	if (self->archive->client.switcher != NULL)

	{

		r1 = r2 = (self->archive->client.switcher)

			((struct archive *)self->archive, self->data, data2);

		self->data = data2;

	}

	else

	{

		/* Attempt to call close and open instead */

		if (self->archive->client.closer != NULL)

			r1 = (self->archive->client.closer)

				((struct archive *)self->archive, self->data);

		self->data = data2;

		if (self->archive->client.opener != NULL)

			r2 = (self->archive->client.opener)

				((struct archive *)self->archive, self->data);

	}

	return (r1 < r2) ? r1 : r2;

}

int

archive_read_set_open_callback(struct archive *_a,

    archive_open_callback *client_opener)

{

	struct archive_read *a = (struct archive_read *)_a;

	archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,

	    "archive_read_set_open_callback");

	a->client.opener = client_opener;

	return ARCHIVE_OK;

}

int

archive_read_set_read_callback(struct archive *_a,

    archive_read_callback *client_reader)

{

	struct archive_read *a = (struct archive_read *)_a;

	archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,

	    "archive_read_set_read_callback");

	a->client.reader = client_reader;

	return ARCHIVE_OK;

}

int

archive_read_set_skip_callback(struct archive *_a,

    archive_skip_callback *client_skipper)

{

	struct archive_read *a = (struct archive_read *)_a;

	archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,

	    "archive_read_set_skip_callback");

	a->client.skipper = client_skipper;

	return ARCHIVE_OK;

}

int

archive_read_set_seek_callback(struct archive *_a,

    archive_seek_callback *client_seeker)

{

	struct archive_read *a = (struct archive_read *)_a;

	archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,

	    "archive_read_set_seek_callback");

	a->client.seeker = client_seeker;

	return ARCHIVE_OK;

}

int

archive_read_set_close_callback(struct archive *_a,

    archive_close_callback *client_closer)

{

	struct archive_read *a = (struct archive_read *)_a;

	archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,

	    "archive_read_set_close_callback");

	a->client.closer = client_closer;

	return ARCHIVE_OK;

}

int

archive_read_set_switch_callback(struct archive *_a,

    archive_switch_callback *client_switcher)

{

	struct archive_read *a = (struct archive_read *)_a;

	archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,

	    "archive_read_set_switch_callback");

	a->client.switcher = client_switcher;

	return ARCHIVE_OK;

}

int

archive_read_set_callback_data(struct archive *_a, void *client_data)

{

	return archive_read_set_callback_data2(_a, client_data, 0);

}

int

archive_read_set_callback_data2(struct archive *_a, void *client_data,

    unsigned int iindex)

{

	struct archive_read *a = (struct archive_read *)_a;

	archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,

	    "archive_read_set_callback_data2");

	if (a->client.nodes == 0)

	{

		a->client.dataset = (struct archive_read_data_node *)

		    calloc(1, sizeof(*a->client.dataset));

		if (a->client.dataset == NULL)

		{

			archive_set_error(&a->archive, ENOMEM,

				"No memory.");

			return ARCHIVE_FATAL;

		}

		a->client.nodes = 1;

	}

	if (iindex > a->client.nodes - 1)

	{

		archive_set_error(&a->archive, EINVAL,

			"Invalid index specified.");

		return ARCHIVE_FATAL;

	}

	a->client.dataset[iindex].data = client_data;

	a->client.dataset[iindex].begin_position = -1;

	a->client.dataset[iindex].total_size = -1;

	return ARCHIVE_OK;

}

int

archive_read_add_callback_data(struct archive *_a, void *client_data,

    unsigned int iindex)

{

	struct archive_read *a = (struct archive_read *)_a;

	void *p;

	unsigned int i;

	archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,

	    "archive_read_add_callback_data");

	if (iindex > a->client.nodes) {

		archive_set_error(&a->archive, EINVAL,

			"Invalid index specified.");

		return ARCHIVE_FATAL;

	}

	p = realloc(a->client.dataset, sizeof(*a->client.dataset)

		* (++(a->client.nodes)));

	if (p == NULL) {

		archive_set_error(&a->archive, ENOMEM,

			"No memory.");

		return ARCHIVE_FATAL;

	}

	a->client.dataset = (struct archive_read_data_node *)p;

	for (i = a->client.nodes - 1; i > iindex && i > 0; i--) {

		a->client.dataset[i].data = a->client.dataset[i-1].data;

		a->client.dataset[i].begin_position = -1;

		a->client.dataset[i].total_size = -1;

	}

	a->client.dataset[iindex].data = client_data;

	a->client.dataset[iindex].begin_position = -1;

	a->client.dataset[iindex].total_size = -1;

	return ARCHIVE_OK;

}

int

archive_read_append_callback_data(struct archive *_a, void *client_data)

{

	struct archive_read *a = (struct archive_read *)_a;

	return archive_read_add_callback_data(_a, client_data, a->client.nodes);

}

int

archive_read_prepend_callback_data(struct archive *_a, void *client_data)

{

	return archive_read_add_callback_data(_a, client_data, 0);

}

int

archive_read_open1(struct archive *_a)

{

	struct archive_read *a = (struct archive_read *)_a;

	struct archive_read_filter *filter, *tmp;

	int slot, e = ARCHIVE_OK;

	unsigned int i;

	archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,

	    "archive_read_open");

	archive_clear_error(&a->archive);

	if (a->client.reader == NULL) {

		archive_set_error(&a->archive, EINVAL,

		    "No reader function provided to archive_read_open");

		a->archive.state = ARCHIVE_STATE_FATAL;

		return (ARCHIVE_FATAL);

	}

	/* Open data source. */

	if (a->client.opener != NULL) {

		e = (a->client.opener)(&a->archive, a->client.dataset[0].data);

		if (e != 0) {

			/* If the open failed, call the closer to clean up. */

			if (a->client.closer) {

				for (i = 0; i < a->client.nodes; i++)

					(a->client.closer)(&a->archive,

					    a->client.dataset[i].data);

			}

			return (e);

		}

	}

	filter = calloc(1, sizeof(*filter));

	if (filter == NULL)

		return (ARCHIVE_FATAL);

	filter->bidder = NULL;

	filter->upstream = NULL;

	filter->archive = a;

	filter->data = a->client.dataset[0].data;

	filter->open = client_open_proxy;

	filter->read = client_read_proxy;

	filter->skip = client_skip_proxy;

	filter->seek = client_seek_proxy;

	filter->close = client_close_proxy;

	filter->sswitch = client_switch_proxy;

	filter->name = "none";

	filter->code = ARCHIVE_FILTER_NONE;

	a->client.dataset[0].begin_position = 0;

	if (!a->filter || !a->bypass_filter_bidding)

	{

		a->filter = filter;

		/* Build out the input pipeline. */

		e = choose_filters(a);

		if (e < ARCHIVE_WARN) {

			a->archive.state = ARCHIVE_STATE_FATAL;

			return (ARCHIVE_FATAL);

		}

	}

	else

	{

		/* Need to add "NONE" type filter at the end of the filter chain */

		tmp = a->filter;

		while (tmp->upstream)

			tmp = tmp->upstream;

		tmp->upstream = filter;

	}

	if (!a->format)

	{

		slot = choose_format(a);

		if (slot < 0) {

			close_filters(a);

			a->archive.state = ARCHIVE_STATE_FATAL;

			return (ARCHIVE_FATAL);

		}

		a->format = &(a->formats[slot]);

	}

	a->archive.state = ARCHIVE_STATE_HEADER;

	/* Ensure libarchive starts from the first node in a multivolume set */

	client_switch_proxy(a->filter, 0);

	return (e);

}

/*

 * Allow each registered stream transform to bid on whether

 * it wants to handle this stream.  Repeat until we've finished

 * building the pipeline.

 */

/* We won't build a filter pipeline with more stages than this. */

#define MAX_NUMBER_FILTERS 25

static int

choose_filters(struct archive_read *a)

{

	int number_bidders, i, bid, best_bid, number_filters;

	struct archive_read_filter_bidder *bidder, *best_bidder;

	struct archive_read_filter *filter;

	ssize_t avail;

	int r;

	for (number_filters = 0; number_filters < MAX_NUMBER_FILTERS; ++number_filters) {

		number_bidders = sizeof(a->bidders) / sizeof(a->bidders[0]);

		best_bid = 0;

		best_bidder = NULL;

		bidder = a->bidders;

		for (i = 0; i < number_bidders; i++, bidder++) {

			if (bidder->bid != NULL) {

				bid = (bidder->bid)(bidder, a->filter);

				if (bid > best_bid) {

					best_bid = bid;

					best_bidder = bidder;

				}

			}

		}

		/* If no bidder, we're done. */

		if (best_bidder == NULL) {

			/* Verify the filter by asking it for some data. */

			__archive_read_filter_ahead(a->filter, 1, &avail);

			if (avail < 0) {

				__archive_read_free_filters(a);

				return (ARCHIVE_FATAL);

			}

			a->archive.compression_name = a->filter->name;

			a->archive.compression_code = a->filter->code;

			return (ARCHIVE_OK);

		}

		filter

		    = (struct archive_read_filter *)calloc(1, sizeof(*filter));

		if (filter == NULL)

			return (ARCHIVE_FATAL);

		filter->bidder = best_bidder;

		filter->archive = a;

		filter->upstream = a->filter;

		a->filter = filter;

		r = (best_bidder->init)(a->filter);

		if (r != ARCHIVE_OK) {

			__archive_read_free_filters(a);

			return (ARCHIVE_FATAL);

		}

	}

	archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,

	    "Input requires too many filters for decoding");

	return (ARCHIVE_FATAL);

}

/*

 * Read header of next entry.

 */

static int

_archive_read_next_header2(struct archive *_a, struct archive_entry *entry)

{

	struct archive_read *a = (struct archive_read *)_a;

	int r1 = ARCHIVE_OK, r2;

	archive_check_magic(_a, ARCHIVE_READ_MAGIC,

	    ARCHIVE_STATE_HEADER | ARCHIVE_STATE_DATA,

	    "archive_read_next_header");

	archive_entry_clear(entry);

	archive_clear_error(&a->archive);

	/*

	 * If client didn't consume entire data, skip any remainder

	 * (This is especially important for GNU incremental directories.)

	 */

	if (a->archive.state == ARCHIVE_STATE_DATA) {

		r1 = archive_read_data_skip(&a->archive);

		if (r1 == ARCHIVE_EOF)

			archive_set_error(&a->archive, EIO,

			    "Premature end-of-file.");

		if (r1 == ARCHIVE_EOF || r1 == ARCHIVE_FATAL) {

			a->archive.state = ARCHIVE_STATE_FATAL;

			return (ARCHIVE_FATAL);

		}

	}

	/* Record start-of-header offset in uncompressed stream. */

	a->header_position = a->filter->position;

	++_a->file_count;

	r2 = (a->format->read_header)(a, entry);

	/*

	 * EOF and FATAL are persistent at this layer.  By

	 * modifying the state, we guarantee that future calls to

	 * read a header or read data will fail.

	 */

	switch (r2) {

	case ARCHIVE_EOF:

		a->archive.state = ARCHIVE_STATE_EOF;

		--_a->file_count;/* Revert a file counter. */

		break;

	case ARCHIVE_OK:

		a->archive.state = ARCHIVE_STATE_DATA;

		break;

	case ARCHIVE_WARN:

		a->archive.state = ARCHIVE_STATE_DATA;

		break;

	case ARCHIVE_RETRY:

		break;

	case ARCHIVE_FATAL:

		a->archive.state = ARCHIVE_STATE_FATAL;

		break;

	}

	__archive_reset_read_data(&a->archive);

	a->data_start_node = a->client.cursor;

	/* EOF always wins; otherwise return the worst error. */

	return (r2 < r1 || r2 == ARCHIVE_EOF) ? r2 : r1;

}

static int

_archive_read_next_header(struct archive *_a, struct archive_entry **entryp)

{

	int ret;

	struct archive_read *a = (struct archive_read *)_a;

	*entryp = NULL;

	ret = _archive_read_next_header2(_a, a->entry);

	*entryp = a->entry;

	return ret;

}

/*

 * Allow each registered format to bid on whether it wants to handle

 * the next entry.  Return index of winning bidder.

 */

static int

choose_format(struct archive_read *a)

{

	int slots;

	int i;

	int bid, best_bid;

	int best_bid_slot;

	slots = sizeof(a->formats) / sizeof(a->formats[0]);

	best_bid = -1;

	best_bid_slot = -1;

	/* Set up a->format for convenience of bidders. */

	a->format = &(a->formats[0]);

	for (i = 0; i < slots; i++, a->format++) {

		if (a->format->bid) {

			bid = (a->format->bid)(a, best_bid);

			if (bid == ARCHIVE_FATAL)

				return (ARCHIVE_FATAL);

			if (a->filter->position != 0)

				__archive_read_seek(a, 0, SEEK_SET);

			if ((bid > best_bid) || (best_bid_slot < 0)) {

				best_bid = bid;

				best_bid_slot = i;

			}

		}

	}

	/*

	 * There were no bidders; this is a serious programmer error

	 * and demands a quick and definitive abort.

	 */

	if (best_bid_slot < 0) {

		archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,

		    "No formats registered");

		return (ARCHIVE_FATAL);

	}

	/*

	 * There were bidders, but no non-zero bids; this means we

	 * can't support this stream.

	 */

	if (best_bid < 1) {

		archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,

		    "Unrecognized archive format");

		return (ARCHIVE_FATAL);

	}

	return (best_bid_slot);

}

/*

 * Return the file offset (within the uncompressed data stream) where

 * the last header started.

 */

la_int64_t

archive_read_header_position(struct archive *_a)

{

	struct archive_read *a = (struct archive_read *)_a;

	archive_check_magic(_a, ARCHIVE_READ_MAGIC,

	    ARCHIVE_STATE_ANY, "archive_read_header_position");

	return (a->header_position);

}

/*

 * Returns 1 if the archive contains at least one encrypted entry.

 * If the archive format not support encryption at all

 * ARCHIVE_READ_FORMAT_ENCRYPTION_UNSUPPORTED is returned.

 * If for any other reason (e.g. not enough data read so far)

 * we cannot say whether there are encrypted entries, then

 * ARCHIVE_READ_FORMAT_ENCRYPTION_DONT_KNOW is returned.

 * In general, this function will return values below zero when the

 * reader is uncertain or totally incapable of encryption support.

 * When this function returns 0 you can be sure that the reader

 * supports encryption detection but no encrypted entries have

 * been found yet.

 *

 * NOTE: If the metadata/header of an archive is also encrypted, you

 * cannot rely on the number of encrypted entries. That is why this

 * function does not return the number of encrypted entries but#

 * just shows that there are some.

 */

int

archive_read_has_encrypted_entries(struct archive *_a)

{

	struct archive_read *a = (struct archive_read *)_a;

	int format_supports_encryption = archive_read_format_capabilities(_a)

			& (ARCHIVE_READ_FORMAT_CAPS_ENCRYPT_DATA | ARCHIVE_READ_FORMAT_CAPS_ENCRYPT_METADATA);

	if (!_a || !format_supports_encryption) {

		/* Format in general doesn't support encryption */

		return ARCHIVE_READ_FORMAT_ENCRYPTION_UNSUPPORTED;

	}

	/* A reader potentially has read enough data now. */

	if (a->format && a->format->has_encrypted_entries) {

		return (a->format->has_encrypted_entries)(a);

	}

	/* For any other reason we cannot say how many entries are there. */

	return ARCHIVE_READ_FORMAT_ENCRYPTION_DONT_KNOW;

}

/*

 * Returns a bitmask of capabilities that are supported by the archive format reader.

 * If the reader has no special capabilities, ARCHIVE_READ_FORMAT_CAPS_NONE is returned.

 */

int

archive_read_format_capabilities(struct archive *_a)

{

	struct archive_read *a = (struct archive_read *)_a;

	if (a && a->format && a->format->format_capabilties) {

		return (a->format->format_capabilties)(a);

	}

	return ARCHIVE_READ_FORMAT_CAPS_NONE;

}

/*

 * Read data from an archive entry, using a read(2)-style interface.

 * This is a convenience routine that just calls

 * archive_read_data_block and copies the results into the client

 * buffer, filling any gaps with zero bytes.  Clients using this

 * API can be completely ignorant of sparse-file issues; sparse files

 * will simply be padded with nulls.

 *

 * DO NOT intermingle calls to this function and archive_read_data_block

 * to read a single entry body.

 */

la_ssize_t

archive_read_data(struct archive *_a, void *buff, size_t s)

{

	struct archive *a = (struct archive *)_a;

	char	*dest;

	const void *read_buf;

	size_t	 bytes_read;

	size_t	 len;

	int	 r;

	bytes_read = 0;

	dest = (char *)buff;

	while (s > 0) {

		if (a->read_data_remaining == 0) {

			read_buf = a->read_data_block;

			a->read_data_is_posix_read = 1;

			a->read_data_requested = s;

			r = archive_read_data_block(a, &read_buf,

			    &a->read_data_remaining, &a->read_data_offset);

			a->read_data_block = read_buf;

			if (r == ARCHIVE_EOF)

				return (bytes_read);

			/*

			 * Error codes are all negative, so the status

			 * return here cannot be confused with a valid

			 * byte count.  (ARCHIVE_OK is zero.)

			 */

			if (r < ARCHIVE_OK)

				return (r);

		}

		if (a->read_data_offset < a->read_data_output_offset) {

			archive_set_error(a, ARCHIVE_ERRNO_FILE_FORMAT,

			    "Encountered out-of-order sparse blocks");

			return (ARCHIVE_RETRY);

		}

		/* Compute the amount of zero padding needed. */

		if (a->read_data_output_offset + (int64_t)s <

		    a->read_data_offset) {

			len = s;

		} else if (a->read_data_output_offset <

		    a->read_data_offset) {

			len = (size_t)(a->read_data_offset -

			    a->read_data_output_offset);

		} else

			len = 0;

		/* Add zeroes. */

		memset(dest, 0, len);

		s -= len;

		a->read_data_output_offset += len;

		dest += len;

		bytes_read += len;

		/* Copy data if there is any space left. */