More -Wwrite-strings cleanup and make sure you can actually play it.

[dragonfly.git] / contrib / 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 1.14 2005/04/06 04:19:30 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);
        archive_string_empty(&a->error_string);

        /*
         * 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);
                }
                if (ret != ARCHIVE_OK)
                        return (ret);
        }

        /* 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);

        if (a->format->read_data_skip != NULL)
                r = (a->format->read_data_skip)(a);
        else {
                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 (*read_data_skip)(struct archive *),
    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].read_data_skip = read_data_skip;
                        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. */
}