FreeBSD-5.3/lib/libarchive/archive_read.c
/*-
* Copyright (c) 2003-2004 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
* in this position and unchanged.
* 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: src/lib/libarchive/archive_read.c,v 1.12 2004/08/14 03:45:45 kientzle Exp $");
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "archive.h"
#include "archive_entry.h"
#include "archive_private.h"
static int choose_decompressor(struct archive *, const void*, size_t);
static int choose_format(struct archive *);
/*
* Allocate, initialize and return a struct archive object.
*/
struct archive *
archive_read_new(void)
{
struct archive *a;
char *nulls;
a = malloc(sizeof(*a));
memset(a, 0, sizeof(*a));
a->user_uid = geteuid();
a->magic = ARCHIVE_READ_MAGIC;
a->bytes_per_block = ARCHIVE_DEFAULT_BYTES_PER_BLOCK;
a->null_length = 1024;
nulls = malloc(a->null_length);
memset(nulls, 0, a->null_length);
a->nulls = nulls;
a->state = ARCHIVE_STATE_NEW;
a->entry = archive_entry_new();
/* We always support uncompressed archives. */
archive_read_support_compression_none((struct archive*)a);
return (a);
}
/*
* Set the block size.
*/
/*
int
archive_read_set_bytes_per_block(struct archive *a, int bytes_per_block)
{
archive_check_magic(a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW);
if (bytes_per_block < 1)
bytes_per_block = 1;
a->bytes_per_block = bytes_per_block;
return (0);
}
*/
/*
* Open the archive
*/
int
archive_read_open(struct archive *a, void *client_data,
archive_open_callback *opener, archive_read_callback *reader,
archive_close_callback *closer)
{
const void *buffer;
ssize_t bytes_read;
int high_bidder;
int e;
archive_check_magic(a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW);
if (reader == NULL)
__archive_errx(1,
"No reader function provided to archive_read_open");
a->client_reader = reader;
a->client_opener = opener;
a->client_closer = closer;
a->client_data = client_data;
a->state = ARCHIVE_STATE_HEADER;
/* Open data source. */
if (a->client_opener != NULL) {
e =(a->client_opener)(a, a->client_data);
if (e != 0)
return (e);
}
/* Read first block now for format detection. */
bytes_read = (a->client_reader)(a, a->client_data, &buffer);
/* client_reader should have already set error information. */
if (bytes_read < 0)
return (ARCHIVE_FATAL);
/* An empty archive is a serious error. */
if (bytes_read == 0) {
archive_set_error(a, ARCHIVE_ERRNO_FILE_FORMAT,
"Empty input file");
return (ARCHIVE_FATAL);
}
/* Select a decompression routine. */
high_bidder = choose_decompressor(a, buffer, bytes_read);
if (high_bidder < 0)
return (ARCHIVE_FATAL);
/* Initialize decompression routine with the first block of data. */
e = (a->decompressors[high_bidder].init)(a, buffer, bytes_read);
return (e);
}
/*
* Allow each registered decompression routine to bid on whether it
* wants to handle this stream. Return index of winning bidder.
*/
static int
choose_decompressor(struct archive *a, const void *buffer, size_t bytes_read)
{
int decompression_slots, i, bid, best_bid, best_bid_slot;
decompression_slots = sizeof(a->decompressors) /
sizeof(a->decompressors[0]);
best_bid = -1;
best_bid_slot = -1;
for (i = 0; i < decompression_slots; i++) {
if (a->decompressors[i].bid) {
bid = (a->decompressors[i].bid)(buffer, bytes_read);
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_errx(1, "No decompressors were registered; you "
"must call at least one "
"archive_read_support_compression_XXX function in order "
"to successfully read an archive.");
/*
* 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_ERRNO_FILE_FORMAT,
"Unrecognized archive format");
return (ARCHIVE_FATAL);
}
return (best_bid_slot);
}
/*
* Read header of next entry.
*/
int
archive_read_next_header(struct archive *a, struct archive_entry **entryp)
{
struct archive_entry *entry;
int slot, ret;
archive_check_magic(a, ARCHIVE_READ_MAGIC,
ARCHIVE_STATE_HEADER | ARCHIVE_STATE_DATA);
*entryp = NULL;
entry = a->entry;
archive_entry_clear(entry);
/*
* If client didn't consume entire data, skip any remainder
* (This is especially important for GNU incremental directories.)
*/
if (a->state == ARCHIVE_STATE_DATA) {
ret = archive_read_data_skip(a);
if (ret == ARCHIVE_EOF) {
archive_set_error(a, EIO, "Premature end-of-file.");
a->state = ARCHIVE_STATE_FATAL;
return (ARCHIVE_FATAL);
}
}
/* Record start-of-header. */
a->header_position = a->file_position;
slot = choose_format(a);
if (slot < 0) {
a->state = ARCHIVE_STATE_FATAL;
return (ARCHIVE_FATAL);
}
a->format = &(a->formats[slot]);
a->pformat_data = &(a->format->format_data);
ret = (a->format->read_header)(a, entry);
/*
* EOF and FATAL are persistent at this layer. By
* modifying the state, we gaurantee that future calls to
* read a header or read data will fail.
*/
switch (ret) {
case ARCHIVE_EOF:
a->state = ARCHIVE_STATE_EOF;
break;
case ARCHIVE_OK:
a->state = ARCHIVE_STATE_DATA;
break;
case ARCHIVE_WARN:
a->state = ARCHIVE_STATE_DATA;
break;
case ARCHIVE_RETRY:
break;
case ARCHIVE_FATAL:
a->state = ARCHIVE_STATE_FATAL;
break;
}
*entryp = entry;
a->read_data_output_offset = 0;
a->read_data_remaining = 0;
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 *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 and a->pformat_data for convenience of bidders. */
a->format = &(a->formats[0]);
for (i = 0; i < slots; i++, a->format++) {
if (a->format->bid) {
a->pformat_data = &(a->format->format_data);
bid = (a->format->bid)(a);
if (bid == ARCHIVE_FATAL)
return (ARCHIVE_FATAL);
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_errx(1, "No formats were registered; you must "
"invoke at least one archive_read_support_format_XXX "
"function in order to successfully read an archive.");
/*
* 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_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)
{
return (a->header_position);
}
/*
* 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)
{
off_t remaining;
char *dest;
size_t bytes_read;
size_t len;
int r;
bytes_read = 0;
dest = buff;
while (s > 0) {
if (a->read_data_remaining <= 0) {
r = archive_read_data_block(a,
(const void **)&a->read_data_block,
&a->read_data_remaining,
&a->read_data_offset);
if (r == ARCHIVE_EOF)
return (bytes_read);
if (r != ARCHIVE_OK)
return (r);
}
if (a->read_data_offset < a->read_data_output_offset) {
remaining =
a->read_data_output_offset - a->read_data_offset;
if (remaining > (off_t)s)
remaining = (off_t)s;
len = (size_t)remaining;
memset(dest, 0, len);
a->read_data_output_offset += len;
s -= len;
bytes_read += len;
} else {
len = a->read_data_remaining;
if (len > s)
len = s;
memcpy(dest, a->read_data_block, len);
s -= len;
a->read_data_remaining -= len;
a->read_data_output_offset += len;
a->read_data_offset += len;
dest += len;
bytes_read += len;
}
}
return (ARCHIVE_OK);
}
/*
* Skip over all remaining data in this entry.
*/
int
archive_read_data_skip(struct archive *a)
{
int r;
const void *buff;
ssize_t size;
off_t offset;
archive_check_magic(a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_DATA);
while ((r = archive_read_data_block(a, &buff, &size, &offset)) ==
ARCHIVE_OK)
;
if (r == ARCHIVE_EOF)
r = ARCHIVE_OK;
a->state = ARCHIVE_STATE_HEADER;
return (r);
}
/*
* 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.
*/
int
archive_read_data_block(struct archive *a,
const void **buff, size_t *size, off_t *offset)
{
archive_check_magic(a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_DATA);
if (a->format->read_data == NULL) {
archive_set_error(a, ARCHIVE_ERRNO_PROGRAMMER,
"Internal error: "
"No format_read_data_block function registered");
return (ARCHIVE_FATAL);
}
return (a->format->read_data)(a, buff, size, offset);
}
/*
* Close the file and release most resources.
*
* Be careful: client might just call read_new and then read_finish.
* Don't assume we actually read anything or performed any non-trivial
* initialization.
*/
int
archive_read_close(struct archive *a)
{
archive_check_magic(a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_ANY);
a->state = ARCHIVE_STATE_CLOSED;
/* Call cleanup functions registered by optional components. */
if (a->cleanup_archive_extract != NULL)
(a->cleanup_archive_extract)(a);
/* TODO: Finish the format processing. */
/* Close the input machinery. */
if (a->compression_finish != NULL)
(a->compression_finish)(a);
return (ARCHIVE_OK);
}
/*
* Release memory and other resources.
*/
void
archive_read_finish(struct archive *a)
{
int i;
int slots;
archive_check_magic(a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_ANY);
if (a->state != ARCHIVE_STATE_CLOSED)
archive_read_close(a);
/* Cleanup format-specific data. */
slots = sizeof(a->formats) / sizeof(a->formats[0]);
for (i = 0; i < slots; i++) {
a->pformat_data = &(a->formats[i].format_data);
if (a->formats[i].cleanup)
(a->formats[i].cleanup)(a);
}
/* Casting a pointer to int allows us to remove 'const.' */
free((void *)(uintptr_t)(const void *)a->nulls);
archive_string_free(&a->error_string);
if (a->entry)
archive_entry_free(a->entry);
a->magic = 0;
free(a);
}
/*
* Used internally by read format handlers to register their bid and
* initialization functions.
*/
int
__archive_read_register_format(struct archive *a,
void *format_data,
int (*bid)(struct archive *),
int (*read_header)(struct archive *, struct archive_entry *),
int (*read_data)(struct archive *, const void **, size_t *, off_t *),
int (*cleanup)(struct archive *))
{
int i, number_slots;
archive_check_magic(a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW);
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].read_header = read_header;
a->formats[i].read_data = read_data;
a->formats[i].cleanup = cleanup;
a->formats[i].format_data = format_data;
return (ARCHIVE_OK);
}
}
__archive_errx(1, "Not enough slots for format registration");
return (ARCHIVE_FATAL); /* Never actually called. */
}
/*
* Used internally by decompression routines to register their bid and
* initialization functions.
*/
int
__archive_read_register_compression(struct archive *a,
int (*bid)(const void *, size_t),
int (*init)(struct archive *, const void *, size_t))
{
int i, number_slots;
archive_check_magic(a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW);
number_slots = sizeof(a->decompressors) / sizeof(a->decompressors[0]);
for (i = 0; i < number_slots; i++) {
if (a->decompressors[i].bid == bid)
return (ARCHIVE_OK); /* We've already installed */
if (a->decompressors[i].bid == NULL) {
a->decompressors[i].bid = bid;
a->decompressors[i].init = init;
return (ARCHIVE_OK);
}
}
__archive_errx(1, "Not enough slots for compression registration");
return (ARCHIVE_FATAL); /* Never actually executed. */
}