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Diffstat (limited to 'lib/libarchive/archive_read.c')
| -rw-r--r-- | lib/libarchive/archive_read.c | 1249 |
1 files changed, 1249 insertions, 0 deletions
diff --git a/lib/libarchive/archive_read.c b/lib/libarchive/archive_read.c new file mode 100644 index 0000000..7873d45 --- /dev/null +++ b/lib/libarchive/archive_read.c @@ -0,0 +1,1249 @@ +/*- + * Copyright (c) 2003-2007 Tim Kientzle + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +/* + * 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("$FreeBSD$"); + +#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 build_stream(struct archive_read *); +static int choose_format(struct archive_read *); +static int cleanup_filters(struct archive_read *); +static struct archive_vtable *archive_read_vtable(void); +static int _archive_read_close(struct archive *); +static int _archive_read_free(struct archive *); + +static struct archive_vtable * +archive_read_vtable(void) +{ + static struct archive_vtable av; + static int inited = 0; + + if (!inited) { + av.archive_free = _archive_read_free; + av.archive_close = _archive_read_close; + } + return (&av); +} + +/* + * Allocate, initialize and return a struct archive object. + */ +struct archive * +archive_read_new(void) +{ + struct archive_read *a; + + a = (struct archive_read *)malloc(sizeof(*a)); + if (a == NULL) + return (NULL); + memset(a, 0, sizeof(*a)); + a->archive.magic = ARCHIVE_READ_MAGIC; + + a->archive.state = ARCHIVE_STATE_NEW; + a->entry = archive_entry_new(); + a->archive.vtable = archive_read_vtable(); + + 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, dev_t d, ino_t i) +{ + struct archive_read *a = (struct archive_read *)_a; + __archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_ANY, + "archive_read_extract_set_skip_file"); + a->skip_file_dev = d; + a->skip_file_ino = i; +} + +/* + * Set read options for the format. + */ +int +archive_read_set_format_options(struct archive *_a, const char *s) +{ + struct archive_read *a; + struct archive_format_descriptor *format; + char key[64], val[64]; + char *valp; + size_t i; + int len, r; + + __archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW, + "archive_read_set_format_options"); + + if (s == NULL || *s == '\0') + return (ARCHIVE_OK); + a = (struct archive_read *)_a; + __archive_check_magic(&a->archive, ARCHIVE_READ_MAGIC, + ARCHIVE_STATE_NEW, "archive_read_set_format_options"); + len = 0; + for (i = 0; i < sizeof(a->formats)/sizeof(a->formats[0]); i++) { + format = &a->formats[i]; + if (format == NULL || format->options == NULL || + format->name == NULL) + /* This format does not support option. */ + continue; + + while ((len = __archive_parse_options(s, format->name, + sizeof(key), key, sizeof(val), val)) > 0) { + valp = val[0] == '\0' ? NULL : val; + a->format = format; + r = format->options(a, key, valp); + a->format = NULL; + if (r == ARCHIVE_FATAL) + return (r); + s += len; + } + } + if (len < 0) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC, + "Illegal format options."); + return (ARCHIVE_WARN); + } + return (ARCHIVE_OK); +} + +/* + * Set read options for the filter. + */ +int +archive_read_set_filter_options(struct archive *_a, const char *s) +{ + struct archive_read *a; + struct archive_read_filter *filter; + struct archive_read_filter_bidder *bidder; + char key[64], val[64]; + int len, r; + + __archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW, + "archive_read_set_filter_options"); + + if (s == NULL || *s == '\0') + return (ARCHIVE_OK); + a = (struct archive_read *)_a; + __archive_check_magic(&a->archive, ARCHIVE_READ_MAGIC, + ARCHIVE_STATE_NEW, "archive_read_set_filter_options"); + len = 0; + for (filter = a->filter; filter != NULL; filter = filter->upstream) { + bidder = filter->bidder; + if (bidder == NULL) + continue; + if (bidder->options == NULL) + /* This bidder does not support option */ + continue; + while ((len = __archive_parse_options(s, filter->name, + sizeof(key), key, sizeof(val), val)) > 0) { + if (val[0] == '\0') + r = bidder->options(bidder, key, NULL); + else + r = bidder->options(bidder, key, val); + if (r == ARCHIVE_FATAL) + return (r); + s += len; + } + } + if (len < 0) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC, + "Illegal format options."); + return (ARCHIVE_WARN); + } + return (ARCHIVE_OK); +} + +/* + * Set read options for the format and the filter. + */ +int +archive_read_set_options(struct archive *_a, const char *s) +{ + int r; + + __archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW, + "archive_read_set_options"); + archive_clear_error(_a); + + r = archive_read_set_format_options(_a, s); + if (r != ARCHIVE_OK) + return (r); + r = archive_read_set_filter_options(_a, s); + if (r != ARCHIVE_OK) + return (r); + return (ARCHIVE_OK); +} + +/* + * 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_open2. */ + return archive_read_open2(a, client_data, client_opener, + client_reader, NULL, client_closer); +} + +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); + self->archive->archive.raw_position += r; + return (r); +} + +static int64_t +client_skip_proxy(struct archive_read_filter *self, int64_t request) +{ + int64_t ask, get, total; + /* Limit our maximum seek request to 1GB on platforms + * with 32-bit off_t (such as Windows). */ + int64_t skip_limit = ((int64_t)1) << (sizeof(off_t) * 8 - 2); + + if (self->archive->client.skipper == NULL) + return (0); + total = 0; + for (;;) { + ask = request; + if (ask > skip_limit) + ask = skip_limit; + get = (self->archive->client.skipper)(&self->archive->archive, + self->data, ask); + if (get == 0) + return (total); + request -= get; + self->archive->archive.raw_position += get; + total += get; + } +} + +static int +client_close_proxy(struct archive_read_filter *self) +{ + int r = ARCHIVE_OK; + + if (self->archive->client.closer != NULL) + r = (self->archive->client.closer)((struct archive *)self->archive, + self->data); + self->data = NULL; + return (r); +} + + +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) +{ + struct archive_read *a = (struct archive_read *)_a; + struct archive_read_filter *filter; + int e; + + __archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW, + "archive_read_open"); + archive_clear_error(&a->archive); + + if (client_reader == NULL) + __archive_errx(1, + "No reader function provided to archive_read_open"); + + /* Open data source. */ + if (client_opener != NULL) { + e =(client_opener)(&a->archive, client_data); + if (e != 0) { + /* If the open failed, call the closer to clean up. */ + if (client_closer) + (client_closer)(&a->archive, client_data); + return (e); + } + } + + /* Save the client functions and mock up the initial source. */ + a->client.reader = client_reader; + a->client.skipper = client_skipper; + a->client.closer = client_closer; + + filter = calloc(1, sizeof(*filter)); + if (filter == NULL) + return (ARCHIVE_FATAL); + filter->bidder = NULL; + filter->upstream = NULL; + filter->archive = a; + filter->data = client_data; + filter->read = client_read_proxy; + filter->skip = client_skip_proxy; + filter->close = client_close_proxy; + filter->name = "none"; + filter->code = ARCHIVE_COMPRESSION_NONE; + a->filter = filter; + + /* Build out the input pipeline. */ + e = build_stream(a); + if (e == ARCHIVE_OK) + a->archive.state = ARCHIVE_STATE_HEADER; + + 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 +build_stream(struct archive_read *a) +{ + int number_bidders, i, bid, best_bid; + struct archive_read_filter_bidder *bidder, *best_bidder; + struct archive_read_filter *filter; + ssize_t avail; + int r; + + for (;;) { + 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 final pipelin by asking it for some data. */ + __archive_read_filter_ahead(a->filter, 1, &avail); + if (avail < 0) { + cleanup_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) { + cleanup_filters(a); + return (r); + } + } +} + +/* + * Read header of next entry. + */ +int +archive_read_next_header2(struct archive *_a, struct archive_entry *entry) +{ + struct archive_read *a = (struct archive_read *)_a; + int slot, ret; + + __archive_check_magic(_a, ARCHIVE_READ_MAGIC, + ARCHIVE_STATE_HEADER | ARCHIVE_STATE_DATA, + "archive_read_next_header"); + + ++_a->file_count; + archive_entry_clear(entry); + archive_clear_error(&a->archive); + + /* + * If no format has yet been chosen, choose one. + */ + if (a->format == NULL) { + slot = choose_format(a); + if (slot < 0) { + a->archive.state = ARCHIVE_STATE_FATAL; + return (ARCHIVE_FATAL); + } + a->format = &(a->formats[slot]); + } + + /* + * 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) { + ret = archive_read_data_skip(&a->archive); + if (ret == ARCHIVE_EOF) { + archive_set_error(&a->archive, EIO, "Premature end-of-file."); + a->archive.state = ARCHIVE_STATE_FATAL; + return (ARCHIVE_FATAL); + } + if (ret != ARCHIVE_OK) + return (ret); + } + + /* Record start-of-header. */ + a->header_position = a->archive.file_position; + + ret = (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 (ret) { + case ARCHIVE_EOF: + a->archive.state = ARCHIVE_STATE_EOF; + 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; + } + + a->read_data_output_offset = 0; + a->read_data_remaining = 0; + return (ret); +} + +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 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) { + 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, 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); +} + +/* + * 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_read *a = (struct archive_read *)_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; + r = archive_read_data_block(&a->archive, &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, 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 + (off_t)s < + a->read_data_offset) { + len = s; + } else if (a->read_data_output_offset < + a->read_data_offset) { + len = 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; + } + } + return (bytes_read); +} + +#if ARCHIVE_API_VERSION < 3 +/* + * Obsolete function provided for compatibility only. Note that the API + * of this function doesn't allow the caller to detect if the remaining + * data from the archive entry is shorter than the buffer provided, or + * even if an error occurred while reading data. + */ +int +archive_read_data_into_buffer(struct archive *a, void *d, ssize_t len) +{ + + archive_read_data(a, d, len); + return (ARCHIVE_OK); +} +#endif + +/* + * 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; + off_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); +} + +/* + * 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) +{ + 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_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. + */ +static int +_archive_read_close(struct archive *_a) +{ + struct archive_read *a = (struct archive_read *)_a; + int r = ARCHIVE_OK, r1 = ARCHIVE_OK; + size_t i, n; + + __archive_check_magic(&a->archive, ARCHIVE_READ_MAGIC, + ARCHIVE_STATE_ANY, "archive_read_close"); + archive_clear_error(&a->archive); + a->archive.state = ARCHIVE_STATE_CLOSED; + + + /* Call cleanup functions registered by optional components. */ + if (a->cleanup_archive_extract != NULL) + r = (a->cleanup_archive_extract)(a); + + /* TODO: Clean up the formatters. */ + + /* Release the filter objects. */ + r1 = cleanup_filters(a); + if (r1 < r) + r = r1; + + /* Release the bidder objects. */ + n = sizeof(a->bidders)/sizeof(a->bidders[0]); + for (i = 0; i < n; i++) { + if (a->bidders[i].free != NULL) { + r1 = (a->bidders[i].free)(&a->bidders[i]); + if (r1 < r) + r = r1; + } + } + + return (r); +} + +static int +cleanup_filters(struct archive_read *a) +{ + int r = ARCHIVE_OK; + /* Clean up the filter pipeline. */ + while (a->filter != NULL) { + struct archive_read_filter *t = a->filter->upstream; + if (a->filter->close != NULL) { + int r1 = (a->filter->close)(a->filter); + if (r1 < r) + r = r1; + } + free(a->filter->buffer); + free(a->filter); + a->filter = t; + } + return r; +} + +/* + * Release memory and other resources. + */ +static int +_archive_read_free(struct archive *_a) +{ + struct archive_read *a = (struct archive_read *)_a; + int i; + int slots; + int r = ARCHIVE_OK; + + __archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_ANY, + "archive_read_free"); + if (a->archive.state != ARCHIVE_STATE_CLOSED) + r = archive_read_close(&a->archive); + + /* 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); + } + + archive_string_free(&a->archive.error_string); + if (a->entry) + archive_entry_free(a->entry); + a->archive.magic = 0; + free(a); +#if ARCHIVE_API_VERSION > 1 + return (r); +#endif +} + +/* + * 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 (*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 *, off_t *), + int (*read_data_skip)(struct archive_read *), + int (*cleanup)(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].cleanup = cleanup; + a->formats[i].data = format_data; + a->formats[i].name = name; + 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. + */ +struct archive_read_filter_bidder * +__archive_read_get_bidder(struct archive_read *a) +{ + int i, number_slots; + + __archive_check_magic(&a->archive, + ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW, + "__archive_read_get_bidder"); + + 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])); + return (a->bidders + i); + } + } + + __archive_errx(1, "Not enough slots for compression registration"); + return (NULL); /* Never actually executed. */ +} + +/* + * The next three functions comprise the peek/consume internal I/O + * system used by archive format readers. This system allows fairly + * flexible read-ahead and allows the I/O code to operate in a + * zero-copy manner most of the time. + * + * 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. The __archive_read_skip() is an optimization; it scans ahead + * very quickly (it usually translates into a seek() operation if + * you're reading uncompressed disk files). + * + * 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(). + * You can consume more than you asked for; you just can't consume + * more than is available. If you consume everything that's + * immediately available, the next read_ahead() call will pull + * the next block. + * * "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), then + * repeat until you're done. + * * "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. + * + * TODO: Someday, provide a more generic __archive_read_seek() for + * those cases where it's useful. This is tricky because there are lots + * of cases where seek() is not available (reading gzip data from a + * network socket, for instance), so there needs to be a good way to + * communicate whether seek() is available and users of that interface + * need to use non-seeking strategies whenever seek() is not available. + */ + +/* + * 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, returns NULL + * if request is not met. + * + * 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. + */ + +/* + * This is tricky. We need to provide our clients with pointers to + * contiguous blocks of memory but we want to avoid copying whenever + * possible. + * + * Mostly, this code returns pointers directly into the block of data + * provided by the client_read routine. It can do this unless the + * request would split across blocks. In that case, we have to copy + * into an internal buffer to combine reads. + */ +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) { /* 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->position += bytes_read; + 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. This should be called after + * __archive_read_ahead() returns data to you. Don't try to move + * ahead by more than the amount of data available according to + * __archive_read_ahead(). + */ +/* + * Mark the appropriate data as used. Note that the request here will + * often be much smaller than the size of the previous read_ahead + * request. + */ +ssize_t +__archive_read_consume(struct archive_read *a, size_t request) +{ + ssize_t r; + r = __archive_read_filter_consume(a->filter, request); + a->archive.file_position += r; + return (r); +} + +ssize_t +__archive_read_filter_consume(struct archive_read_filter * filter, + size_t request) +{ + if (filter->avail > 0) { + /* Read came from copy buffer. */ + filter->next += request; + filter->avail -= request; + } else { + /* Read came from client buffer. */ + filter->client_next += request; + filter->client_avail -= request; + } + return (request); +} + +/* + * Move the file pointer ahead by an arbitrary amount. If you're + * reading uncompressed data from a disk file, this will actually + * translate into a seek() operation. Even in cases where seek() + * isn't feasible, this at least pushes the read-and-discard loop + * down closer to the data source. + */ +int64_t +__archive_read_skip(struct archive_read *a, int64_t request) +{ + int64_t skipped = __archive_read_skip_lenient(a, 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(&a->archive, + ARCHIVE_ERRNO_MISC, + "Truncated input file (needed %jd bytes, only %jd available)", + (intmax_t)request, (intmax_t)skipped); + return (ARCHIVE_FATAL); +} + +int64_t +__archive_read_skip_lenient(struct archive_read *a, int64_t request) +{ + int64_t skipped = __archive_read_filter_skip(a->filter, request); + if (skipped > 0) + a->archive.file_position += skipped; + return (skipped); +} + +int64_t +__archive_read_filter_skip(struct archive_read_filter *filter, int64_t request) +{ + int64_t bytes_skipped, total_bytes_skipped = 0; + size_t min; + + if (filter->fatal) + return (-1); + /* + * If there is data in the buffers already, use that first. + */ + if (filter->avail > 0) { + min = minimum(request, (off_t)filter->avail); + bytes_skipped = __archive_read_filter_consume(filter, min); + request -= bytes_skipped; + total_bytes_skipped += bytes_skipped; + } + if (filter->client_avail > 0) { + min = minimum(request, (int64_t)filter->client_avail); + bytes_skipped = __archive_read_filter_consume(filter, min); + request -= bytes_skipped; + total_bytes_skipped += bytes_skipped; + } + if (request == 0) + return (total_bytes_skipped); + /* + * If a client_skipper was provided, try that first. + */ +#if ARCHIVE_API_VERSION < 2 + if ((filter->skip != NULL) && (request < SSIZE_MAX)) { +#else + if (filter->skip != NULL) { +#endif + bytes_skipped = (filter->skip)(filter, request); + if (bytes_skipped < 0) { /* error */ + filter->client_total = filter->client_avail = 0; + filter->client_next = filter->client_buff = NULL; + filter->fatal = 1; + return (bytes_skipped); + } + total_bytes_skipped += bytes_skipped; + request -= bytes_skipped; + filter->client_next = filter->client_buff; + filter->client_avail = filter->client_total = 0; + } + /* + * Note that client_skipper will usually not satisfy the + * full request (due to low-level blocking concerns), + * so even if client_skipper is provided, we may still + * have to use ordinary reads to finish out the request. + */ + while (request > 0) { + ssize_t bytes_read; + (void)__archive_read_filter_ahead(filter, 1, &bytes_read); + if (bytes_read < 0) + return (bytes_read); + if (bytes_read == 0) { + return (total_bytes_skipped); + } + min = (size_t)(minimum(bytes_read, request)); + bytes_read = __archive_read_filter_consume(filter, min); + total_bytes_skipped += bytes_read; + request -= bytes_read; + } + return (total_bytes_skipped); +} |
