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/*-
* 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 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, int64_t d, 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) {
__archive_read_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.
*/
static int
choose_filters(struct archive_read *a)
{
int number_bidders, i, bid, best_bid, n;
struct archive_read_filter_bidder *bidder, *best_bidder;
struct archive_read_filter *filter;
ssize_t avail;
int r;
for (n = 0; n < 25; ++n) {
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_close_filters(a);
__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_close_filters(a);
__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.
*/
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 uncapable 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.
*/
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. */
if (s > 0) {
len = a->read_data_remaining;
if (len > s)
len = s;
memcpy(dest, a->read_data_block, len);
s -= len;
a->read_data_block += len;
a->read_data_remaining -= len;
a->read_data_output_offset += len;
a->read_data_offset += len;
dest += len;
bytes_read += len;
}
}
a->read_data_is_posix_read = 0;
a->read_data_requested = 0;
return (bytes_read);
}
/*
* Reset the read_data_* variables, used for starting a new entry.
*/
void __archive_reset_read_data(struct archive * a)
{
a->read_data_output_offset = 0;
a->read_data_remaining = 0;
a->read_data_is_posix_read = 0;
a->read_data_requested = 0;
/* extra resets, from rar.c */
a->read_data_block = NULL;
a->read_data_offset = 0;
}
/*
* Skip over all remaining data in this entry.
*/
int
archive_read_data_skip(struct archive *_a)
{
struct archive_read *a = (struct archive_read *)_a;
int r;
const void *buff;
size_t size;
int64_t offset;
archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_DATA,
"archive_read_data_skip");
if (a->format->read_data_skip != NULL)
r = (a->format->read_data_skip)(a);
else {
while ((r = archive_read_data_block(&a->archive,
&buff, &size, &offset))
== ARCHIVE_OK)
;
}
if (r == ARCHIVE_EOF)
r = ARCHIVE_OK;
a->archive.state = ARCHIVE_STATE_HEADER;
return (r);
}
int64_t
archive_seek_data(struct archive *_a, int64_t offset, int whence)
{
struct archive_read *a = (struct archive_read *)_a;
archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_DATA,
"archive_seek_data_block");
if (a->format->seek_data == NULL) {
archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER,
"Internal error: "
"No format_seek_data_block function registered");
return (ARCHIVE_FATAL);
}
return (a->format->seek_data)(a, offset, whence);
}
/*
* Read the next block of entry data from the archive.
* This is a zero-copy interface; the client receives a pointer,
* size, and file offset of the next available block of data.
*
* Returns ARCHIVE_OK if the operation is successful, ARCHIVE_EOF if
* the end of entry is encountered.
*/
static int
_archive_read_data_block(struct archive *_a,
const void **buff, size_t *size, int64_t *offset)
{
struct archive_read *a = (struct archive_read *)_a;
archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_DATA,
"archive_read_data_block");
if (a->format->read_data == NULL) {
archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER,
"Internal error: "
"No format->read_data function registered");
return (ARCHIVE_FATAL);
}
return (a->format->read_data)(a, buff, size, offset);
}
int
__archive_read_close_filters(struct archive_read *a)
{
struct archive_read_filter *f = a->filter;
int r = ARCHIVE_OK;
/* Close each filter in the pipeline. */
while (f != NULL) {
struct archive_read_filter *t = f->upstream;
if (!f->closed && f->close != NULL) {
int r1 = (f->close)(f);
f->closed = 1;
if (r1 < r)
r = r1;
}
free(f->buffer);
f->buffer = NULL;
f = t;
}
return r;
}
void
__archive_read_free_filters(struct archive_read *a)
{
while (a->filter != NULL) {
struct archive_read_filter *t = a->filter->upstream;
free(a->filter);
a->filter = t;
}
}
/*
* return the count of # of filters in use
*/
static int
_archive_filter_count(struct archive *_a)
{
struct archive_read *a = (struct archive_read *)_a;
struct archive_read_filter *p = a->filter;
int count = 0;
while(p) {
count++;
p = p->upstream;
}
return count;
}
/*
* Close the file and all I/O.
*/
static int
_archive_read_close(struct archive *_a)
{
struct archive_read *a = (struct archive_read *)_a;
int r = ARCHIVE_OK, r1 = ARCHIVE_OK;
archive_check_magic(&a->archive, ARCHIVE_READ_MAGIC,
ARCHIVE_STATE_ANY | ARCHIVE_STATE_FATAL, "archive_read_close");
if (a->archive.state == ARCHIVE_STATE_CLOSED)
return (ARCHIVE_OK);
archive_clear_error(&a->archive);
a->archive.state = ARCHIVE_STATE_CLOSED;
/* TODO: Clean up the formatters. */
/* Release the filter objects. */
r1 = __archive_read_close_filters(a);
if (r1 < r)
r = r1;
return (r);
}
/*
* Release memory and other resources.
*/
static int
_archive_read_free(struct archive *_a)
{
struct archive_read *a = (struct archive_read *)_a;
struct archive_read_passphrase *p;
int i, n;
int slots;
int r = ARCHIVE_OK;
if (_a == NULL)
return (ARCHIVE_OK);
archive_check_magic(_a, ARCHIVE_READ_MAGIC,
ARCHIVE_STATE_ANY | ARCHIVE_STATE_FATAL, "archive_read_free");
if (a->archive.state != ARCHIVE_STATE_CLOSED
&& a->archive.state != ARCHIVE_STATE_FATAL)
r = archive_read_close(&a->archive);
/* Call cleanup functions registered by optional components. */
if (a->cleanup_archive_extract != NULL)
r = (a->cleanup_archive_extract)(a);
/* Cleanup format-specific data. */
slots = sizeof(a->formats) / sizeof(a->formats[0]);
for (i = 0; i < slots; i++) {
a->format = &(a->formats[i]);
if (a->formats[i].cleanup)
(a->formats[i].cleanup)(a);
}
/* Free the filters */
__archive_read_free_filters(a);
/* Release the bidder objects. */
n = sizeof(a->bidders)/sizeof(a->bidders[0]);
for (i = 0; i < n; i++) {
if (a->bidders[i].free != NULL) {
int r1 = (a->bidders[i].free)(&a->bidders[i]);
if (r1 < r)
r = r1;
}
}
/* Release passphrase list. */
p = a->passphrases.first;
while (p != NULL) {
struct archive_read_passphrase *np = p->next;
/* A passphrase should be cleaned. */
memset(p->passphrase, 0, strlen(p->passphrase));
free(p->passphrase);
free(p);
p = np;
}
archive_string_free(&a->archive.error_string);
archive_entry_free(a->entry);
a->archive.magic = 0;
__archive_clean(&a->archive);
free(a->client.dataset);
free(a);
return (r);
}
static struct archive_read_filter *
get_filter(struct archive *_a, int n)
{
struct archive_read *a = (struct archive_read *)_a;
struct archive_read_filter *f = a->filter;
/* We use n == -1 for 'the last filter', which is always the
* client proxy. */
if (n == -1 && f != NULL) {
struct archive_read_filter *last = f;
f = f->upstream;
while (f != NULL) {
last = f;
f = f->upstream;
}
return (last);
}
if (n < 0)
return NULL;
while (n > 0 && f != NULL) {
f = f->upstream;
--n;
}
return (f);
}
static int
_archive_filter_code(struct archive *_a, int n)
{
struct archive_read_filter *f = get_filter(_a, n);
return f == NULL ? -1 : f->code;
}
static const char *
_archive_filter_name(struct archive *_a, int n)
{
struct archive_read_filter *f = get_filter(_a, n);
return f == NULL ? NULL : f->name;
}
static int64_t
_archive_filter_bytes(struct archive *_a, int n)
{
struct archive_read_filter *f = get_filter(_a, n);
return f == NULL ? -1 : f->position;
}
/*
* Used internally by read format handlers to register their bid and
* initialization functions.
*/
int
__archive_read_register_format(struct archive_read *a,
void *format_data,
const char *name,
int (*bid)(struct archive_read *, int),
int (*options)(struct archive_read *, const char *, const char *),
int (*read_header)(struct archive_read *, struct archive_entry *),
int (*read_data)(struct archive_read *, const void **, size_t *, int64_t *),
int (*read_data_skip)(struct archive_read *),
int64_t (*seek_data)(struct archive_read *, int64_t, int),
int (*cleanup)(struct archive_read *),
int (*format_capabilities)(struct archive_read *),
int (*has_encrypted_entries)(struct archive_read *))
{
int i, number_slots;
archive_check_magic(&a->archive,
ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
"__archive_read_register_format");
number_slots = sizeof(a->formats) / sizeof(a->formats[0]);
for (i = 0; i < number_slots; i++) {
if (a->formats[i].bid == bid)
return (ARCHIVE_WARN); /* We've already installed */
if (a->formats[i].bid == NULL) {
a->formats[i].bid = bid;
a->formats[i].options = options;
a->formats[i].read_header = read_header;
a->formats[i].read_data = read_data;
a->formats[i].read_data_skip = read_data_skip;
a->formats[i].seek_data = seek_data;
a->formats[i].cleanup = cleanup;
a->formats[i].data = format_data;
a->formats[i].name = name;
a->formats[i].format_capabilties = format_capabilities;
a->formats[i].has_encrypted_entries = has_encrypted_entries;
return (ARCHIVE_OK);
}
}
archive_set_error(&a->archive, ENOMEM,
"Not enough slots for format registration");
return (ARCHIVE_FATAL);
}
/*
* Used internally by decompression routines to register their bid and
* initialization functions.
*/
int
__archive_read_get_bidder(struct archive_read *a,
struct archive_read_filter_bidder **bidder)
{
int i, number_slots;
number_slots = sizeof(a->bidders) / sizeof(a->bidders[0]);
for (i = 0; i < number_slots; i++) {
if (a->bidders[i].bid == NULL) {
memset(a->bidders + i, 0, sizeof(a->bidders[0]));
*bidder = (a->bidders + i);
return (ARCHIVE_OK);
}
}
archive_set_error(&a->archive, ENOMEM,
"Not enough slots for filter registration");
return (ARCHIVE_FATAL);
}
/*
* The next section implements the peek/consume internal I/O
* system used by archive readers. This system allows simple
* read-ahead for consumers while preserving zero-copy operation
* most of the time.
*
* The two key operations:
* * The read-ahead function returns a pointer to a block of data
* that satisfies a minimum request.
* * The consume function advances the file pointer.
*
* In the ideal case, filters generate blocks of data
* and __archive_read_ahead() just returns pointers directly into
* those blocks. Then __archive_read_consume() just bumps those
* pointers. Only if your request would span blocks does the I/O
* layer use a copy buffer to provide you with a contiguous block of
* data.
*
* A couple of useful idioms:
* * "I just want some data." Ask for 1 byte and pay attention to
* the "number of bytes available" from __archive_read_ahead().
* Consume whatever you actually use.
* * "I want to output a large block of data." As above, ask for 1 byte,
* emit all that's available (up to whatever limit you have), consume
* it all, then repeat until you're done. This effectively means that
* you're passing along the blocks that came from your provider.
* * "I want to peek ahead by a large amount." Ask for 4k or so, then
* double and repeat until you get an error or have enough. Note
* that the I/O layer will likely end up expanding its copy buffer
* to fit your request, so use this technique cautiously. This
* technique is used, for example, by some of the format tasting
* code that has uncertain look-ahead needs.
*/
/*
* Looks ahead in the input stream:
* * If 'avail' pointer is provided, that returns number of bytes available
* in the current buffer, which may be much larger than requested.
* * If end-of-file, *avail gets set to zero.
* * If error, *avail gets error code.
* * If request can be met, returns pointer to data.
* * If minimum request cannot be met, returns NULL.
*
* Note: If you just want "some data", ask for 1 byte and pay attention
* to *avail, which will have the actual amount available. If you
* know exactly how many bytes you need, just ask for that and treat
* a NULL return as an error.
*
* Important: This does NOT move the file pointer. See
* __archive_read_consume() below.
*/
const void *
__archive_read_ahead(struct archive_read *a, size_t min, ssize_t *avail)
{
return (__archive_read_filter_ahead(a->filter, min, avail));
}
const void *
__archive_read_filter_ahead(struct archive_read_filter *filter,
size_t min, ssize_t *avail)
{
ssize_t bytes_read;
size_t tocopy;
if (filter->fatal) {
if (avail)
*avail = ARCHIVE_FATAL;
return (NULL);
}
/*
* Keep pulling more data until we can satisfy the request.
*/
for (;;) {
/*
* If we can satisfy from the copy buffer (and the
* copy buffer isn't empty), we're done. In particular,
* note that min == 0 is a perfectly well-defined
* request.
*/
if (filter->avail >= min && filter->avail > 0) {
if (avail != NULL)
*avail = filter->avail;
return (filter->next);
}
/*
* We can satisfy directly from client buffer if everything
* currently in the copy buffer is still in the client buffer.
*/
if (filter->client_total >= filter->client_avail + filter->avail
&& filter->client_avail + filter->avail >= min) {
/* "Roll back" to client buffer. */
filter->client_avail += filter->avail;
filter->client_next -= filter->avail;
/* Copy buffer is now empty. */
filter->avail = 0;
filter->next = filter->buffer;
/* Return data from client buffer. */
if (avail != NULL)
*avail = filter->client_avail;
return (filter->client_next);
}
/* Move data forward in copy buffer if necessary. */
if (filter->next > filter->buffer &&
filter->next + min > filter->buffer + filter->buffer_size) {
if (filter->avail > 0)
memmove(filter->buffer, filter->next,
filter->avail);
filter->next = filter->buffer;
}
/* If we've used up the client data, get more. */
if (filter->client_avail <= 0) {
if (filter->end_of_file) {
if (avail != NULL)
*avail = 0;
return (NULL);
}
bytes_read = (filter->read)(filter,
&filter->client_buff);
if (bytes_read < 0) { /* Read error. */
filter->client_total = filter->client_avail = 0;
filter->client_next =
filter->client_buff = NULL;
filter->fatal = 1;
if (avail != NULL)
*avail = ARCHIVE_FATAL;
return (NULL);
}
if (bytes_read == 0) {
/* Check for another client object first */
if (filter->archive->client.cursor !=
filter->archive->client.nodes - 1) {
if (client_switch_proxy(filter,
filter->archive->client.cursor + 1)
== ARCHIVE_OK)
continue;
}
/* Premature end-of-file. */
filter->client_total = filter->client_avail = 0;
filter->client_next =
filter->client_buff = NULL;
filter->end_of_file = 1;
/* Return whatever we do have. */
if (avail != NULL)
*avail = filter->avail;
return (NULL);
}
filter->client_total = bytes_read;
filter->client_avail = filter->client_total;
filter->client_next = filter->client_buff;
} else {
/*
* We can't satisfy the request from the copy
* buffer or the existing client data, so we
* need to copy more client data over to the
* copy buffer.
*/
/* Ensure the buffer is big enough. */
if (min > filter->buffer_size) {
size_t s, t;
char *p;
/* Double the buffer; watch for overflow. */
s = t = filter->buffer_size;
if (s == 0)
s = min;
while (s < min) {
t *= 2;
if (t <= s) { /* Integer overflow! */
archive_set_error(
&filter->archive->archive,
ENOMEM,
"Unable to allocate copy"
" buffer");
filter->fatal = 1;
if (avail != NULL)
*avail = ARCHIVE_FATAL;
return (NULL);
}
s = t;
}
/* Now s >= min, so allocate a new buffer. */
p = (char *)malloc(s);
if (p == NULL) {
archive_set_error(
&filter->archive->archive,
ENOMEM,
"Unable to allocate copy buffer");
filter->fatal = 1;
if (avail != NULL)
*avail = ARCHIVE_FATAL;
return (NULL);
}
/* Move data into newly-enlarged buffer. */
if (filter->avail > 0)
memmove(p, filter->next, filter->avail);
free(filter->buffer);
filter->next = filter->buffer = p;
filter->buffer_size = s;
}
/* We can add client data to copy buffer. */
/* First estimate: copy to fill rest of buffer. */
tocopy = (filter->buffer + filter->buffer_size)
- (filter->next + filter->avail);
/* Don't waste time buffering more than we need to. */
if (tocopy + filter->avail > min)
tocopy = min - filter->avail;
/* Don't copy more than is available. */
if (tocopy > filter->client_avail)
tocopy = filter->client_avail;
memcpy(filter->next + filter->avail,
filter->client_next, tocopy);
/* Remove this data from client buffer. */
filter->client_next += tocopy;
filter->client_avail -= tocopy;
/* add it to copy buffer. */
filter->avail += tocopy;
}
}
}
/*
* Move the file pointer forward.
*/
int64_t
__archive_read_consume(struct archive_read *a, int64_t request)
{
return (__archive_read_filter_consume(a->filter, request));
}
int64_t
__archive_read_filter_consume(struct archive_read_filter * filter,
int64_t request)
{
int64_t skipped;
if (request < 0)
return ARCHIVE_FATAL;
if (request == 0)
return 0;
skipped = advance_file_pointer(filter, request);
if (skipped == request)
return (skipped);
/* We hit EOF before we satisfied the skip request. */
if (skipped < 0) /* Map error code to 0 for error message below. */
skipped = 0;
archive_set_error(&filter->archive->archive,
ARCHIVE_ERRNO_MISC,
"Truncated input file (needed %jd bytes, only %jd available)",
(intmax_t)request, (intmax_t)skipped);
return (ARCHIVE_FATAL);
}
/*
* Advance the file pointer by the amount requested.
* Returns the amount actually advanced, which may be less than the
* request if EOF is encountered first.
* Returns a negative value if there's an I/O error.
*/
static int64_t
advance_file_pointer(struct archive_read_filter *filter, int64_t request)
{
int64_t bytes_skipped, total_bytes_skipped = 0;
ssize_t bytes_read;
size_t min;
if (filter->fatal)
return (-1);
/* Use up the copy buffer first. */
if (filter->avail > 0) {
min = (size_t)minimum(request, (int64_t)filter->avail);
filter->next += min;
filter->avail -= min;
request -= min;
filter->position += min;
total_bytes_skipped += min;
}
/* Then use up the client buffer. */
if (filter->client_avail > 0) {
min = (size_t)minimum(request, (int64_t)filter->client_avail);
filter->client_next += min;
filter->client_avail -= min;
request -= min;
filter->position += min;
total_bytes_skipped += min;
}
if (request == 0)
return (total_bytes_skipped);
/* If there's an optimized skip function, use it. */
if (filter->skip != NULL) {
bytes_skipped = (filter->skip)(filter, request);
if (bytes_skipped < 0) { /* error */
filter->fatal = 1;
return (bytes_skipped);
}
filter->position += bytes_skipped;
total_bytes_skipped += bytes_skipped;
request -= bytes_skipped;
if (request == 0)
return (total_bytes_skipped);
}
/* Use ordinary reads as necessary to complete the request. */
for (;;) {
bytes_read = (filter->read)(filter, &filter->client_buff);
if (bytes_read < 0) {
filter->client_buff = NULL;
filter->fatal = 1;
return (bytes_read);
}
if (bytes_read == 0) {
if (filter->archive->client.cursor !=
filter->archive->client.nodes - 1) {
if (client_switch_proxy(filter,
filter->archive->client.cursor + 1)
== ARCHIVE_OK)
continue;
}
filter->client_buff = NULL;
filter->end_of_file = 1;
return (total_bytes_skipped);
}
if (bytes_read >= request) {
filter->client_next =
((const char *)filter->client_buff) + request;
filter->client_avail = (size_t)(bytes_read - request);
filter->client_total = bytes_read;
total_bytes_skipped += request;
filter->position += request;
return (total_bytes_skipped);
}
filter->position += bytes_read;
total_bytes_skipped += bytes_read;
request -= bytes_read;
}
}
/**
* Returns ARCHIVE_FAILED if seeking isn't supported.
*/
int64_t
__archive_read_seek(struct archive_read *a, int64_t offset, int whence)
{
return __archive_read_filter_seek(a->filter, offset, whence);
}
int64_t
__archive_read_filter_seek(struct archive_read_filter *filter, int64_t offset,
int whence)
{
struct archive_read_client *client;
int64_t r;
unsigned int cursor;
if (filter->closed || filter->fatal)
return (ARCHIVE_FATAL);
if (filter->seek == NULL)
return (ARCHIVE_FAILED);
client = &(filter->archive->client);
switch (whence) {
case SEEK_CUR:
/* Adjust the offset and use SEEK_SET instead */
offset += filter->position;
case SEEK_SET:
cursor = 0;
while (1)
{
if (client->dataset[cursor].begin_position < 0 ||
client->dataset[cursor].total_size < 0 ||
client->dataset[cursor].begin_position +
client->dataset[cursor].total_size - 1 > offset ||
cursor + 1 >= client->nodes)
break;
r = client->dataset[cursor].begin_position +
client->dataset[cursor].total_size;
client->dataset[++cursor].begin_position = r;
}
while (1) {
r = client_switch_proxy(filter, cursor);
if (r != ARCHIVE_OK)
return r;
if ((r = client_seek_proxy(filter, 0, SEEK_END)) < 0)
return r;
client->dataset[cursor].total_size = r;
if (client->dataset[cursor].begin_position +
client->dataset[cursor].total_size - 1 > offset ||
cursor + 1 >= client->nodes)
break;
r = client->dataset[cursor].begin_position +
client->dataset[cursor].total_size;
client->dataset[++cursor].begin_position = r;
}
offset -= client->dataset[cursor].begin_position;
if (offset < 0
|| offset > client->dataset[cursor].total_size)
return ARCHIVE_FATAL;
if ((r = client_seek_proxy(filter, offset, SEEK_SET)) < 0)
return r;
break;
case SEEK_END:
cursor = 0;
while (1) {
if (client->dataset[cursor].begin_position < 0 ||
client->dataset[cursor].total_size < 0 ||
cursor + 1 >= client->nodes)
break;
r = client->dataset[cursor].begin_position +
client->dataset[cursor].total_size;
client->dataset[++cursor].begin_position = r;
}
while (1) {
r = client_switch_proxy(filter, cursor);
if (r != ARCHIVE_OK)
return r;
if ((r = client_seek_proxy(filter, 0, SEEK_END)) < 0)
return r;
client->dataset[cursor].total_size = r;
r = client->dataset[cursor].begin_position +
client->dataset[cursor].total_size;
if (cursor + 1 >= client->nodes)
break;
client->dataset[++cursor].begin_position = r;
}
while (1) {
if (r + offset >=
client->dataset[cursor].begin_position)
break;
offset += client->dataset[cursor].total_size;
if (cursor == 0)
break;
cursor--;
r = client->dataset[cursor].begin_position +
client->dataset[cursor].total_size;
}
offset = (r + offset) - client->dataset[cursor].begin_position;
if ((r = client_switch_proxy(filter, cursor)) != ARCHIVE_OK)
return r;
r = client_seek_proxy(filter, offset, SEEK_SET);
if (r < ARCHIVE_OK)
return r;
break;
default:
return (ARCHIVE_FATAL);
}
r += client->dataset[cursor].begin_position;
if (r >= 0) {
/*
* Ouch. Clearing the buffer like this hurts, especially
* at bid time. A lot of our efficiency at bid time comes
* from having bidders reuse the data we've already read.
*
* TODO: If the seek request is in data we already
* have, then don't call the seek callback.
*
* TODO: Zip seeks to end-of-file at bid time. If
* other formats also start doing this, we may need to
* find a way for clients to fudge the seek offset to
* a block boundary.
*
* Hmmm... If whence was SEEK_END, we know the file
* size is (r - offset). Can we use that to simplify
* the TODO items above?
*/
filter->avail = filter->client_avail = 0;
filter->next = filter->buffer;
filter->position = r;
filter->end_of_file = 0;
}
return r;
}
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