1 files changed, 903 insertions, 0 deletions

diff --git a/libarchive/archive_read_support_format_zip.c b/libarchive/archive_read_support_format_zip.c
new file mode 100644
index 000000000000..207915708343
--- /dev/null
+++ b/libarchive/archive_read_support_format_zip.c
@@ -0,0 +1,903 @@
+/*-
+ * Copyright (c) 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.
+ * 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.
+ */
+
+#include "archive_platform.h"
+__FBSDID("$FreeBSD: head/lib/libarchive/archive_read_support_format_zip.c 201102 2009-12-28 03:11:36Z kientzle $");
+
+#ifdef HAVE_ERRNO_H
+#include <errno.h>
+#endif
+#include <stdio.h>
+#ifdef HAVE_STDLIB_H
+#include <stdlib.h>
+#endif
+#include <time.h>
+#ifdef HAVE_ZLIB_H
+#include <zlib.h>
+#endif
+
+#include "archive.h"
+#include "archive_entry.h"
+#include "archive_private.h"
+#include "archive_read_private.h"
+#include "archive_endian.h"
+
+#ifndef HAVE_ZLIB_H
+#include "archive_crc32.h"
+#endif
+
+struct zip {
+	/* entry_bytes_remaining is the number of bytes we expect. */
+	int64_t			entry_bytes_remaining;
+	int64_t			entry_offset;
+
+	/* These count the number of bytes actually read for the entry. */
+	int64_t			entry_compressed_bytes_read;
+	int64_t			entry_uncompressed_bytes_read;
+
+	/* Running CRC32 of the decompressed data */
+	unsigned long		entry_crc32;
+
+	unsigned		version;
+	unsigned		system;
+	unsigned		flags;
+	unsigned		compression;
+	const char *		compression_name;
+	time_t			mtime;
+	time_t			ctime;
+	time_t			atime;
+	mode_t			mode;
+	uid_t			uid;
+	gid_t			gid;
+
+	/* Flags to mark progress of decompression. */
+	char			decompress_init;
+	char			end_of_entry;
+
+	unsigned long		crc32;
+	ssize_t			filename_length;
+	ssize_t			extra_length;
+	int64_t			uncompressed_size;
+	int64_t			compressed_size;
+
+	unsigned char 		*uncompressed_buffer;
+	size_t 			uncompressed_buffer_size;
+#ifdef HAVE_ZLIB_H
+	z_stream		stream;
+	char			stream_valid;
+#endif
+
+	struct archive_string	pathname;
+	struct archive_string	extra;
+	char	format_name[64];
+};
+
+#define ZIP_LENGTH_AT_END	8
+
+struct zip_file_header {
+	char	signature[4];
+	char	version[2];
+	char	flags[2];
+	char	compression[2];
+	char	timedate[4];
+	char	crc32[4];
+	char	compressed_size[4];
+	char	uncompressed_size[4];
+	char	filename_length[2];
+	char	extra_length[2];
+};
+
+static const char *compression_names[] = {
+	"uncompressed",
+	"shrinking",
+	"reduced-1",
+	"reduced-2",
+	"reduced-3",
+	"reduced-4",
+	"imploded",
+	"reserved",
+	"deflation"
+};
+
+static int	archive_read_format_zip_bid(struct archive_read *);
+static int	archive_read_format_zip_cleanup(struct archive_read *);
+static int	archive_read_format_zip_read_data(struct archive_read *,
+		    const void **, size_t *, off_t *);
+static int	archive_read_format_zip_read_data_skip(struct archive_read *a);
+static int	archive_read_format_zip_read_header(struct archive_read *,
+		    struct archive_entry *);
+static int	zip_read_data_deflate(struct archive_read *a, const void **buff,
+		    size_t *size, off_t *offset);
+static int	zip_read_data_none(struct archive_read *a, const void **buff,
+		    size_t *size, off_t *offset);
+static int	zip_read_file_header(struct archive_read *a,
+		    struct archive_entry *entry, struct zip *zip);
+static time_t	zip_time(const char *);
+static void process_extra(const void* extra, struct zip* zip);
+
+int
+archive_read_support_format_zip(struct archive *_a)
+{
+	struct archive_read *a = (struct archive_read *)_a;
+	struct zip *zip;
+	int r;
+
+	zip = (struct zip *)malloc(sizeof(*zip));
+	if (zip == NULL) {
+		archive_set_error(&a->archive, ENOMEM, "Can't allocate zip data");
+		return (ARCHIVE_FATAL);
+	}
+	memset(zip, 0, sizeof(*zip));
+
+	r = __archive_read_register_format(a,
+	    zip,
+	    "zip",
+	    archive_read_format_zip_bid,
+	    NULL,
+	    archive_read_format_zip_read_header,
+	    archive_read_format_zip_read_data,
+	    archive_read_format_zip_read_data_skip,
+	    archive_read_format_zip_cleanup);
+
+	if (r != ARCHIVE_OK)
+		free(zip);
+	return (ARCHIVE_OK);
+}
+
+
+static int
+archive_read_format_zip_bid(struct archive_read *a)
+{
+	const char *p;
+	const void *buff;
+	ssize_t bytes_avail, offset;
+
+	if ((p = __archive_read_ahead(a, 4, NULL)) == NULL)
+		return (-1);
+
+	/*
+	 * Bid of 30 here is: 16 bits for "PK",
+	 * next 16-bit field has four options (-2 bits).
+	 * 16 + 16-2 = 30.
+	 */
+	if (p[0] == 'P' && p[1] == 'K') {
+		if ((p[2] == '\001' && p[3] == '\002')
+		    || (p[2] == '\003' && p[3] == '\004')
+		    || (p[2] == '\005' && p[3] == '\006')
+		    || (p[2] == '\007' && p[3] == '\010')
+		    || (p[2] == '0' && p[3] == '0'))
+			return (30);
+	}
+
+	/*
+	 * Attempt to handle self-extracting archives
+	 * by noting a PE header and searching forward
+	 * up to 128k for a 'PK\003\004' marker.
+	 */
+	if (p[0] == 'M' && p[1] == 'Z') {
+		/*
+		 * TODO: Optimize by initializing 'offset' to an
+		 * estimate of the likely start of the archive data
+		 * based on values in the PE header.  Note that we
+		 * don't need to be exact, but we mustn't skip too
+		 * far.  The search below will compensate if we
+		 * undershoot.
+		 */
+		offset = 0;
+		while (offset < 124000) {
+			/* Get 4k of data beyond where we stopped. */
+			buff = __archive_read_ahead(a, offset + 4096,
+			    &bytes_avail);
+			if (buff == NULL)
+				break;
+			p = (const char *)buff + offset;
+			while (p + 9 < (const char *)buff + bytes_avail) {
+				if (p[0] == 'P' && p[1] == 'K' /* signature */
+				    && p[2] == 3 && p[3] == 4 /* File entry */
+				    && p[8] == 8 /* compression == deflate */
+				    && p[9] == 0 /* High byte of compression */
+					)
+				{
+					return (30);
+				}
+				++p;
+			}
+			offset = p - (const char *)buff;
+		}
+	}
+
+	return (0);
+}
+
+/*
+ * Search forward for a "PK\003\004" file header.  This handles the
+ * case of self-extracting archives, where there is an executable
+ * prepended to the ZIP archive.
+ */
+static int
+skip_sfx(struct archive_read *a)
+{
+	const void *h;
+	const char *p, *q;
+	size_t skip;
+	ssize_t bytes;
+
+	/*
+	 * TODO: We should be able to skip forward by a bunch
+	 * by lifting some values from the PE header.  We don't
+	 * need to be exact (we're still going to search forward
+	 * to find the header), but it will speed things up and
+	 * reduce the chance of a false positive.
+	 */
+	for (;;) {
+		h = __archive_read_ahead(a, 4, &bytes);
+		if (bytes < 4)
+			return (ARCHIVE_FATAL);
+		p = h;
+		q = p + bytes;
+
+		/*
+		 * Scan ahead until we find something that looks
+		 * like the zip header.
+		 */
+		while (p + 4 < q) {
+			switch (p[3]) {
+			case '\004':
+				/* TODO: Additional verification here. */
+				if (memcmp("PK\003\004", p, 4) == 0) {
+					skip = p - (const char *)h;
+					__archive_read_consume(a, skip);
+					return (ARCHIVE_OK);
+				}
+				p += 4;
+				break;
+			case '\003': p += 1; break;
+			case 'K': p += 2; break;
+			case 'P': p += 3; break;
+			default: p += 4; break;
+			}
+		}
+		skip = p - (const char *)h;
+		__archive_read_consume(a, skip);
+	}
+}
+
+static int
+archive_read_format_zip_read_header(struct archive_read *a,
+    struct archive_entry *entry)
+{
+	const void *h;
+	const char *signature;
+	struct zip *zip;
+	int r = ARCHIVE_OK, r1;
+
+	a->archive.archive_format = ARCHIVE_FORMAT_ZIP;
+	if (a->archive.archive_format_name == NULL)
+		a->archive.archive_format_name = "ZIP";
+
+	zip = (struct zip *)(a->format->data);
+	zip->decompress_init = 0;
+	zip->end_of_entry = 0;
+	zip->entry_uncompressed_bytes_read = 0;
+	zip->entry_compressed_bytes_read = 0;
+	zip->entry_crc32 = crc32(0, NULL, 0);
+	if ((h = __archive_read_ahead(a, 4, NULL)) == NULL)
+		return (ARCHIVE_FATAL);
+
+	signature = (const char *)h;
+	if (signature[0] == 'M' && signature[1] == 'Z') {
+		/* This is an executable?  Must be self-extracting... */
+		r = skip_sfx(a);
+		if (r < ARCHIVE_WARN)
+			return (r);
+		if ((h = __archive_read_ahead(a, 4, NULL)) == NULL)
+			return (ARCHIVE_FATAL);
+		signature = (const char *)h;
+	}
+
+	if (signature[0] != 'P' || signature[1] != 'K') {
+		archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
+		    "Bad ZIP file");
+		return (ARCHIVE_FATAL);
+	}
+
+	/*
+	 * "PK00" signature is used for "split" archives that
+	 * only have a single segment.  This means we can just
+	 * skip the PK00; the first real file header should follow.
+	 */
+	if (signature[2] == '0' && signature[3] == '0') {
+		__archive_read_consume(a, 4);
+		if ((h = __archive_read_ahead(a, 4, NULL)) == NULL)
+			return (ARCHIVE_FATAL);
+		signature = (const char *)h;
+		if (signature[0] != 'P' || signature[1] != 'K') {
+			archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
+			    "Bad ZIP file");
+			return (ARCHIVE_FATAL);
+		}
+	}
+
+	if (signature[2] == '\001' && signature[3] == '\002') {
+		/* Beginning of central directory. */
+		return (ARCHIVE_EOF);
+	}
+
+	if (signature[2] == '\003' && signature[3] == '\004') {
+		/* Regular file entry. */
+		r1 = zip_read_file_header(a, entry, zip);
+		if (r1 != ARCHIVE_OK)
+			return (r1);
+		return (r);
+	}
+
+	if (signature[2] == '\005' && signature[3] == '\006') {
+		/* End-of-archive record. */
+		return (ARCHIVE_EOF);
+	}
+
+	if (signature[2] == '\007' && signature[3] == '\010') {
+		/*
+		 * We should never encounter this record here;
+		 * see ZIP_LENGTH_AT_END handling below for details.
+		 */
+		archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
+		    "Bad ZIP file: Unexpected end-of-entry record");
+		return (ARCHIVE_FATAL);
+	}
+
+	archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
+	    "Damaged ZIP file or unsupported format variant (%d,%d)",
+	    signature[2], signature[3]);
+	return (ARCHIVE_FATAL);
+}
+
+static int
+zip_read_file_header(struct archive_read *a, struct archive_entry *entry,
+    struct zip *zip)
+{
+	const struct zip_file_header *p;
+	const void *h;
+
+	if ((p = __archive_read_ahead(a, sizeof *p, NULL)) == NULL) {
+		archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
+		    "Truncated ZIP file header");
+		return (ARCHIVE_FATAL);
+	}
+
+	zip->version = p->version[0];
+	zip->system = p->version[1];
+	zip->flags = archive_le16dec(p->flags);
+	zip->compression = archive_le16dec(p->compression);
+	if (zip->compression <
+	    sizeof(compression_names)/sizeof(compression_names[0]))
+		zip->compression_name = compression_names[zip->compression];
+	else
+		zip->compression_name = "??";
+	zip->mtime = zip_time(p->timedate);
+	zip->ctime = 0;
+	zip->atime = 0;
+	zip->mode = 0;
+	zip->uid = 0;
+	zip->gid = 0;
+	zip->crc32 = archive_le32dec(p->crc32);
+	zip->filename_length = archive_le16dec(p->filename_length);
+	zip->extra_length = archive_le16dec(p->extra_length);
+	zip->uncompressed_size = archive_le32dec(p->uncompressed_size);
+	zip->compressed_size = archive_le32dec(p->compressed_size);
+
+	__archive_read_consume(a, sizeof(struct zip_file_header));
+
+
+	/* Read the filename. */
+	if ((h = __archive_read_ahead(a, zip->filename_length, NULL)) == NULL) {
+		archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
+		    "Truncated ZIP file header");
+		return (ARCHIVE_FATAL);
+	}
+	if (archive_string_ensure(&zip->pathname, zip->filename_length) == NULL)
+		__archive_errx(1, "Out of memory");
+	archive_strncpy(&zip->pathname, h, zip->filename_length);
+	__archive_read_consume(a, zip->filename_length);
+	archive_entry_set_pathname(entry, zip->pathname.s);
+
+	if (zip->pathname.s[archive_strlen(&zip->pathname) - 1] == '/')
+		zip->mode = AE_IFDIR | 0777;
+	else
+		zip->mode = AE_IFREG | 0777;
+
+	/* Read the extra data. */
+	if ((h = __archive_read_ahead(a, zip->extra_length, NULL)) == NULL) {
+		archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
+		    "Truncated ZIP file header");
+		return (ARCHIVE_FATAL);
+	}
+	process_extra(h, zip);
+	__archive_read_consume(a, zip->extra_length);
+
+	/* Populate some additional entry fields: */
+	archive_entry_set_mode(entry, zip->mode);
+	archive_entry_set_uid(entry, zip->uid);
+	archive_entry_set_gid(entry, zip->gid);
+	archive_entry_set_mtime(entry, zip->mtime, 0);
+	archive_entry_set_ctime(entry, zip->ctime, 0);
+	archive_entry_set_atime(entry, zip->atime, 0);
+	/* Set the size only if it's meaningful. */
+	if (0 == (zip->flags & ZIP_LENGTH_AT_END))
+		archive_entry_set_size(entry, zip->uncompressed_size);
+
+	zip->entry_bytes_remaining = zip->compressed_size;
+	zip->entry_offset = 0;
+
+	/* If there's no body, force read_data() to return EOF immediately. */
+	if (0 == (zip->flags & ZIP_LENGTH_AT_END)
+	    && zip->entry_bytes_remaining < 1)
+		zip->end_of_entry = 1;
+
+	/* Set up a more descriptive format name. */
+	sprintf(zip->format_name, "ZIP %d.%d (%s)",
+	    zip->version / 10, zip->version % 10,
+	    zip->compression_name);
+	a->archive.archive_format_name = zip->format_name;
+
+	return (ARCHIVE_OK);
+}
+
+/* Convert an MSDOS-style date/time into Unix-style time. */
+static time_t
+zip_time(const char *p)
+{
+	int msTime, msDate;
+	struct tm ts;
+
+	msTime = (0xff & (unsigned)p[0]) + 256 * (0xff & (unsigned)p[1]);
+	msDate = (0xff & (unsigned)p[2]) + 256 * (0xff & (unsigned)p[3]);
+
+	memset(&ts, 0, sizeof(ts));
+	ts.tm_year = ((msDate >> 9) & 0x7f) + 80; /* Years since 1900. */
+	ts.tm_mon = ((msDate >> 5) & 0x0f) - 1; /* Month number. */
+	ts.tm_mday = msDate & 0x1f; /* Day of month. */
+	ts.tm_hour = (msTime >> 11) & 0x1f;
+	ts.tm_min = (msTime >> 5) & 0x3f;
+	ts.tm_sec = (msTime << 1) & 0x3e;
+	ts.tm_isdst = -1;
+	return mktime(&ts);
+}
+
+static int
+archive_read_format_zip_read_data(struct archive_read *a,
+    const void **buff, size_t *size, off_t *offset)
+{
+	int r;
+	struct zip *zip;
+
+	zip = (struct zip *)(a->format->data);
+
+	/*
+	 * If we hit end-of-entry last time, clean up and return
+	 * ARCHIVE_EOF this time.
+	 */
+	if (zip->end_of_entry) {
+		*offset = zip->entry_uncompressed_bytes_read;
+		*size = 0;
+		*buff = NULL;
+		return (ARCHIVE_EOF);
+	}
+
+	switch(zip->compression) {
+	case 0:  /* No compression. */
+		r =  zip_read_data_none(a, buff, size, offset);
+		break;
+	case 8: /* Deflate compression. */
+		r =  zip_read_data_deflate(a, buff, size, offset);
+		break;
+	default: /* Unsupported compression. */
+		*buff = NULL;
+		*size = 0;
+		*offset = 0;
+		/* Return a warning. */
+		archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
+		    "Unsupported ZIP compression method (%s)",
+		    zip->compression_name);
+		if (zip->flags & ZIP_LENGTH_AT_END) {
+			/*
+			 * ZIP_LENGTH_AT_END requires us to
+			 * decompress the entry in order to
+			 * skip it, but we don't know this
+			 * compression method, so we give up.
+			 */
+			r = ARCHIVE_FATAL;
+		} else {
+			/* We can't decompress this entry, but we will
+			 * be able to skip() it and try the next entry. */
+			r = ARCHIVE_WARN;
+		}
+		break;
+	}
+	if (r != ARCHIVE_OK)
+		return (r);
+	/* Update checksum */
+	if (*size)
+		zip->entry_crc32 = crc32(zip->entry_crc32, *buff, *size);
+	/* If we hit the end, swallow any end-of-data marker. */
+	if (zip->end_of_entry) {
+		if (zip->flags & ZIP_LENGTH_AT_END) {
+			const char *p;
+
+			if ((p = __archive_read_ahead(a, 16, NULL)) == NULL) {
+				archive_set_error(&a->archive,
+				    ARCHIVE_ERRNO_FILE_FORMAT,
+				    "Truncated ZIP end-of-file record");
+				return (ARCHIVE_FATAL);
+			}
+			zip->crc32 = archive_le32dec(p + 4);
+			zip->compressed_size = archive_le32dec(p + 8);
+			zip->uncompressed_size = archive_le32dec(p + 12);
+			__archive_read_consume(a, 16);
+		}
+		/* Check file size, CRC against these values. */
+		if (zip->compressed_size != zip->entry_compressed_bytes_read) {
+			archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
+			    "ZIP compressed data is wrong size");
+			return (ARCHIVE_WARN);
+		}
+		/* Size field only stores the lower 32 bits of the actual size. */
+		if ((zip->uncompressed_size & UINT32_MAX)
+		    != (zip->entry_uncompressed_bytes_read & UINT32_MAX)) {
+			archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
+			    "ZIP uncompressed data is wrong size");
+			return (ARCHIVE_WARN);
+		}
+		/* Check computed CRC against header */
+		if (zip->crc32 != zip->entry_crc32) {
+			archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
+			    "ZIP bad CRC: 0x%lx should be 0x%lx",
+			    zip->entry_crc32, zip->crc32);
+			return (ARCHIVE_WARN);
+		}
+	}
+
+	/* Return EOF immediately if this is a non-regular file. */
+	if (AE_IFREG != (zip->mode & AE_IFMT))
+		return (ARCHIVE_EOF);
+	return (ARCHIVE_OK);
+}
+
+/*
+ * Read "uncompressed" data.  According to the current specification,
+ * if ZIP_LENGTH_AT_END is specified, then the size fields in the
+ * initial file header are supposed to be set to zero.  This would, of
+ * course, make it impossible for us to read the archive, since we
+ * couldn't determine the end of the file data.  Info-ZIP seems to
+ * include the real size fields both before and after the data in this
+ * case (the CRC only appears afterwards), so this works as you would
+ * expect.
+ *
+ * Returns ARCHIVE_OK if successful, ARCHIVE_FATAL otherwise, sets
+ * zip->end_of_entry if it consumes all of the data.
+ */
+static int
+zip_read_data_none(struct archive_read *a, const void **buff,
+    size_t *size, off_t *offset)
+{
+	struct zip *zip;
+	ssize_t bytes_avail;
+
+	zip = (struct zip *)(a->format->data);
+
+	if (zip->entry_bytes_remaining == 0) {
+		*buff = NULL;
+		*size = 0;
+		*offset = zip->entry_offset;
+		zip->end_of_entry = 1;
+		return (ARCHIVE_OK);
+	}
+	/*
+	 * Note: '1' here is a performance optimization.
+	 * Recall that the decompression layer returns a count of
+	 * available bytes; asking for more than that forces the
+	 * decompressor to combine reads by copying data.
+	 */
+	*buff = __archive_read_ahead(a, 1, &bytes_avail);
+	if (bytes_avail <= 0) {
+		archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
+		    "Truncated ZIP file data");
+		return (ARCHIVE_FATAL);
+	}
+	if (bytes_avail > zip->entry_bytes_remaining)
+		bytes_avail = zip->entry_bytes_remaining;
+	__archive_read_consume(a, bytes_avail);
+	*size = bytes_avail;
+	*offset = zip->entry_offset;
+	zip->entry_offset += *size;
+	zip->entry_bytes_remaining -= *size;
+	zip->entry_uncompressed_bytes_read += *size;
+	zip->entry_compressed_bytes_read += *size;
+	return (ARCHIVE_OK);
+}
+
+#ifdef HAVE_ZLIB_H
+static int
+zip_read_data_deflate(struct archive_read *a, const void **buff,
+    size_t *size, off_t *offset)
+{
+	struct zip *zip;
+	ssize_t bytes_avail;
+	const void *compressed_buff;
+	int r;
+
+	zip = (struct zip *)(a->format->data);
+
+	/* If the buffer hasn't been allocated, allocate it now. */
+	if (zip->uncompressed_buffer == NULL) {
+		zip->uncompressed_buffer_size = 32 * 1024;
+		zip->uncompressed_buffer
+		    = (unsigned char *)malloc(zip->uncompressed_buffer_size);
+		if (zip->uncompressed_buffer == NULL) {
+			archive_set_error(&a->archive, ENOMEM,
+			    "No memory for ZIP decompression");
+			return (ARCHIVE_FATAL);
+		}
+	}
+
+	/* If we haven't yet read any data, initialize the decompressor. */
+	if (!zip->decompress_init) {
+		if (zip->stream_valid)
+			r = inflateReset(&zip->stream);
+		else
+			r = inflateInit2(&zip->stream,
+			    -15 /* Don't check for zlib header */);
+		if (r != Z_OK) {
+			archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
+			    "Can't initialize ZIP decompression.");
+			return (ARCHIVE_FATAL);
+		}
+		/* Stream structure has been set up. */
+		zip->stream_valid = 1;
+		/* We've initialized decompression for this stream. */
+		zip->decompress_init = 1;
+	}
+
+	/*
+	 * Note: '1' here is a performance optimization.
+	 * Recall that the decompression layer returns a count of
+	 * available bytes; asking for more than that forces the
+	 * decompressor to combine reads by copying data.
+	 */
+	compressed_buff = __archive_read_ahead(a, 1, &bytes_avail);
+	if (bytes_avail <= 0) {
+		archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
+		    "Truncated ZIP file body");
+		return (ARCHIVE_FATAL);
+	}
+
+	/*
+	 * A bug in zlib.h: stream.next_in should be marked 'const'
+	 * but isn't (the library never alters data through the
+	 * next_in pointer, only reads it).  The result: this ugly
+	 * cast to remove 'const'.
+	 */
+	zip->stream.next_in = (Bytef *)(uintptr_t)(const void *)compressed_buff;
+	zip->stream.avail_in = bytes_avail;
+	zip->stream.total_in = 0;
+	zip->stream.next_out = zip->uncompressed_buffer;
+	zip->stream.avail_out = zip->uncompressed_buffer_size;
+	zip->stream.total_out = 0;
+
+	r = inflate(&zip->stream, 0);
+	switch (r) {
+	case Z_OK:
+		break;
+	case Z_STREAM_END:
+		zip->end_of_entry = 1;
+		break;
+	case Z_MEM_ERROR:
+		archive_set_error(&a->archive, ENOMEM,
+		    "Out of memory for ZIP decompression");
+		return (ARCHIVE_FATAL);
+	default:
+		archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
+		    "ZIP decompression failed (%d)", r);
+		return (ARCHIVE_FATAL);
+	}
+
+	/* Consume as much as the compressor actually used. */
+	bytes_avail = zip->stream.total_in;
+	__archive_read_consume(a, bytes_avail);
+	zip->entry_bytes_remaining -= bytes_avail;
+	zip->entry_compressed_bytes_read += bytes_avail;
+
+	*offset = zip->entry_offset;
+	*size = zip->stream.total_out;
+	zip->entry_uncompressed_bytes_read += *size;
+	*buff = zip->uncompressed_buffer;
+	zip->entry_offset += *size;
+	return (ARCHIVE_OK);
+}
+#else
+static int
+zip_read_data_deflate(struct archive_read *a, const void **buff,
+    size_t *size, off_t *offset)
+{
+	*buff = NULL;
+	*size = 0;
+	*offset = 0;
+	archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
+	    "libarchive compiled without deflate support (no libz)");
+	return (ARCHIVE_FATAL);
+}
+#endif
+
+static int
+archive_read_format_zip_read_data_skip(struct archive_read *a)
+{
+	struct zip *zip;
+	const void *buff = NULL;
+	off_t bytes_skipped;
+
+	zip = (struct zip *)(a->format->data);
+
+	/* If we've already read to end of data, we're done. */
+	if (zip->end_of_entry)
+		return (ARCHIVE_OK);
+
+	/*
+	 * If the length is at the end, we have no choice but
+	 * to decompress all the data to find the end marker.
+	 */
+	if (zip->flags & ZIP_LENGTH_AT_END) {
+		size_t size;
+		off_t offset;
+		int r;
+		do {
+			r = archive_read_format_zip_read_data(a, &buff,
+			    &size, &offset);
+		} while (r == ARCHIVE_OK);
+		return (r);
+	}
+
+	/*
+	 * If the length is at the beginning, we can skip the
+	 * compressed data much more quickly.
+	 */
+	bytes_skipped = __archive_read_skip(a, zip->entry_bytes_remaining);
+	if (bytes_skipped < 0)
+		return (ARCHIVE_FATAL);
+
+	/* This entry is finished and done. */
+	zip->end_of_entry = 1;
+	return (ARCHIVE_OK);
+}
+
+static int
+archive_read_format_zip_cleanup(struct archive_read *a)
+{
+	struct zip *zip;
+
+	zip = (struct zip *)(a->format->data);
+#ifdef HAVE_ZLIB_H
+	if (zip->stream_valid)
+		inflateEnd(&zip->stream);
+#endif
+	free(zip->uncompressed_buffer);
+	archive_string_free(&(zip->pathname));
+	archive_string_free(&(zip->extra));
+	free(zip);
+	(a->format->data) = NULL;
+	return (ARCHIVE_OK);
+}
+
+/*
+ * The extra data is stored as a list of
+ *	id1+size1+data1 + id2+size2+data2 ...
+ *  triplets.  id and size are 2 bytes each.
+ */
+static void
+process_extra(const void* extra, struct zip* zip)
+{
+	int offset = 0;
+	const char *p = (const char *)extra;
+	while (offset < zip->extra_length - 4)
+	{
+		unsigned short headerid = archive_le16dec(p + offset);
+		unsigned short datasize = archive_le16dec(p + offset + 2);
+		offset += 4;
+		if (offset + datasize > zip->extra_length)
+			break;
+#ifdef DEBUG
+		fprintf(stderr, "Header id 0x%04x, length %d\n",
+		    headerid, datasize);
+#endif
+		switch (headerid) {
+		case 0x0001:
+			/* Zip64 extended information extra field. */
+			if (datasize >= 8)
+				zip->uncompressed_size = archive_le64dec(p + offset);
+			if (datasize >= 16)
+				zip->compressed_size = archive_le64dec(p + offset + 8);
+			break;
+		case 0x5455:
+		{
+			/* Extended time field "UT". */
+			int flags = p[offset];
+			offset++;
+			datasize--;
+			/* Flag bits indicate which dates are present. */
+			if (flags & 0x01)
+			{
+#ifdef DEBUG
+				fprintf(stderr, "mtime: %lld -> %d\n",
+				    (long long)zip->mtime,
+				    archive_le32dec(p + offset));
+#endif
+				if (datasize < 4)
+					break;
+				zip->mtime = archive_le32dec(p + offset);
+				offset += 4;
+				datasize -= 4;
+			}
+			if (flags & 0x02)
+			{
+				if (datasize < 4)
+					break;
+				zip->atime = archive_le32dec(p + offset);
+				offset += 4;
+				datasize -= 4;
+			}
+			if (flags & 0x04)
+			{
+				if (datasize < 4)
+					break;
+				zip->ctime = archive_le32dec(p + offset);
+				offset += 4;
+				datasize -= 4;
+			}
+			break;
+		}
+		case 0x7855:
+			/* Info-ZIP Unix Extra Field (type 2) "Ux". */
+#ifdef DEBUG
+			fprintf(stderr, "uid %d gid %d\n",
+			    archive_le16dec(p + offset),
+			    archive_le16dec(p + offset + 2));
+#endif
+			if (datasize >= 2)
+				zip->uid = archive_le16dec(p + offset);
+			if (datasize >= 4)
+				zip->gid = archive_le16dec(p + offset + 2);
+			break;
+		default:
+			break;
+		}
+		offset += datasize;
+	}
+#ifdef DEBUG
+	if (offset != zip->extra_length)
+	{
+		fprintf(stderr,
+		    "Extra data field contents do not match reported size!");
+	}
+#endif
+}