/*-

 * Copyright (c) 2007 Kai Wang

 * Copyright (c) 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

 *    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.

 */

#include "archive_platform.h"

__FBSDID("$FreeBSD: head/lib/libarchive/archive_read_support_format_ar.c 201101 2009-12-28 03:06:27Z kientzle $");

#ifdef HAVE_SYS_STAT_H

#include <sys/stat.h>

#endif

#ifdef HAVE_ERRNO_H

#include <errno.h>

#endif

#ifdef HAVE_STDLIB_H

#include <stdlib.h>

#endif

#ifdef HAVE_STRING_H

#include <string.h>

#endif

#ifdef HAVE_LIMITS_H

#include <limits.h>

#endif

#include "archive.h"

#include "archive_entry.h"

#include "archive_private.h"

#include "archive_read_private.h"

struct ar {

	int64_t	 entry_bytes_remaining;

	/* unconsumed is purely to track data we've gotten from readahead,

	 * but haven't yet marked as consumed.  Must be paired with

	 * entry_bytes_remaining usage/modification.

	 */

	size_t   entry_bytes_unconsumed;

	int64_t	 entry_offset;

	int64_t	 entry_padding;

	char	*strtab;

	size_t	 strtab_size;

	char	 read_global_header;

};

/*

 * Define structure of the "ar" header.

 */

#define AR_name_offset 0

#define AR_name_size 16

#define AR_date_offset 16

#define AR_date_size 12

#define AR_uid_offset 28

#define AR_uid_size 6

#define AR_gid_offset 34

#define AR_gid_size 6

#define AR_mode_offset 40

#define AR_mode_size 8

#define AR_size_offset 48

#define AR_size_size 10

#define AR_fmag_offset 58

#define AR_fmag_size 2

static int	archive_read_format_ar_bid(struct archive_read *a, int);

static int	archive_read_format_ar_cleanup(struct archive_read *a);

static int	archive_read_format_ar_read_data(struct archive_read *a,

		    const void **buff, size_t *size, int64_t *offset);

static int	archive_read_format_ar_skip(struct archive_read *a);

static int	archive_read_format_ar_read_header(struct archive_read *a,

		    struct archive_entry *e);

static uint64_t	ar_atol8(const char *p, unsigned char_cnt);

static uint64_t	ar_atol10(const char *p, unsigned char_cnt);

static int	ar_parse_gnu_filename_table(struct archive_read *a);

static int	ar_parse_common_header(struct ar *ar, struct archive_entry *,

		    const char *h);

int

archive_read_support_format_ar(struct archive *_a)

{

	struct archive_read *a = (struct archive_read *)_a;

	struct ar *ar;

	int r;

	archive_check_magic(_a, ARCHIVE_READ_MAGIC,

	    ARCHIVE_STATE_NEW, "archive_read_support_format_ar");

	ar = (struct ar *)calloc(1, sizeof(*ar));

	if (ar == NULL) {

		archive_set_error(&a->archive, ENOMEM,

		    "Can't allocate ar data");

		return (ARCHIVE_FATAL);

	}

	ar->strtab = NULL;

	r = __archive_read_register_format(a,

	    ar,

	    "ar",

	    archive_read_format_ar_bid,

	    NULL,

	    archive_read_format_ar_read_header,

	    archive_read_format_ar_read_data,

	    archive_read_format_ar_skip,

	    NULL,

	    archive_read_format_ar_cleanup,

	    NULL,

	    NULL);

	if (r != ARCHIVE_OK) {

		free(ar);

		return (r);

	}

	return (ARCHIVE_OK);

}

static int

archive_read_format_ar_cleanup(struct archive_read *a)

{

	struct ar *ar;

	ar = (struct ar *)(a->format->data);

	if (ar->strtab)

		free(ar->strtab);

	free(ar);

	(a->format->data) = NULL;

	return (ARCHIVE_OK);

}

static int

archive_read_format_ar_bid(struct archive_read *a, int best_bid)

{

	const void *h;

	(void)best_bid; /* UNUSED */

	/*

	 * Verify the 8-byte file signature.

	 * TODO: Do we need to check more than this?

	 */

	if ((h = __archive_read_ahead(a, 8, NULL)) == NULL)

		return (-1);

	if (memcmp(h, "!<arch>\n", 8) == 0) {

		return (64);

	}

	return (-1);

}

static int

_ar_read_header(struct archive_read *a, struct archive_entry *entry,

	struct ar *ar, const char *h, size_t *unconsumed)

{

	char filename[AR_name_size + 1];

	uint64_t number; /* Used to hold parsed numbers before validation. */

	size_t bsd_name_length, entry_size;

	char *p, *st;

	const void *b;

	int r;

	/* Verify the magic signature on the file header. */

	if (strncmp(h + AR_fmag_offset, "`\n", 2) != 0) {

		archive_set_error(&a->archive, EINVAL,

		    "Incorrect file header signature");

		return (ARCHIVE_FATAL);

	}

	/* Copy filename into work buffer. */

	strncpy(filename, h + AR_name_offset, AR_name_size);

	filename[AR_name_size] = '\0';

	/*

	 * Guess the format variant based on the filename.

	 */

	if (a->archive.archive_format == ARCHIVE_FORMAT_AR) {

		/* We don't already know the variant, so let's guess. */

		/*

		 * Biggest clue is presence of '/': GNU starts special

		 * filenames with '/', appends '/' as terminator to

		 * non-special names, so anything with '/' should be

		 * GNU except for BSD long filenames.

		 */

		if (strncmp(filename, "#1/", 3) == 0)

			a->archive.archive_format = ARCHIVE_FORMAT_AR_BSD;

		else if (strchr(filename, '/') != NULL)

			a->archive.archive_format = ARCHIVE_FORMAT_AR_GNU;

		else if (strncmp(filename, "__.SYMDEF", 9) == 0)

			a->archive.archive_format = ARCHIVE_FORMAT_AR_BSD;

		/*

		 * XXX Do GNU/SVR4 'ar' programs ever omit trailing '/'

		 * if name exactly fills 16-byte field?  If so, we

		 * can't assume entries without '/' are BSD. XXX

		 */

	}

	/* Update format name from the code. */

	if (a->archive.archive_format == ARCHIVE_FORMAT_AR_GNU)

		a->archive.archive_format_name = "ar (GNU/SVR4)";

	else if (a->archive.archive_format == ARCHIVE_FORMAT_AR_BSD)

		a->archive.archive_format_name = "ar (BSD)";

	else

		a->archive.archive_format_name = "ar";

	/*

	 * Remove trailing spaces from the filename.  GNU and BSD

	 * variants both pad filename area out with spaces.

	 * This will only be wrong if GNU/SVR4 'ar' implementations

	 * omit trailing '/' for 16-char filenames and we have

	 * a 16-char filename that ends in ' '.

	 */

	p = filename + AR_name_size - 1;

	while (p >= filename && *p == ' ') {

		*p = '\0';

		p--;

	}

	/*

	 * Remove trailing slash unless first character is '/'.

	 * (BSD entries never end in '/', so this will only trim

	 * GNU-format entries.  GNU special entries start with '/'

	 * and are not terminated in '/', so we don't trim anything

	 * that starts with '/'.)

	 */

	if (filename[0] != '/' && p > filename && *p == '/') {

		*p = '\0';

	}

	if (p < filename) {

		archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,

		    "Found entry with empty filename");

		return (ARCHIVE_FATAL);

	}

	/*

	 * '//' is the GNU filename table.

	 * Later entries can refer to names in this table.

	 */

	if (strcmp(filename, "//") == 0) {

		/* This must come before any call to _read_ahead. */

		ar_parse_common_header(ar, entry, h);

		archive_entry_copy_pathname(entry, filename);

		archive_entry_set_filetype(entry, AE_IFREG);

		/* Get the size of the filename table. */

		number = ar_atol10(h + AR_size_offset, AR_size_size);

		if (number > SIZE_MAX || number > 1024 * 1024 * 1024) {

			archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,

			    "Filename table too large");

			return (ARCHIVE_FATAL);

		}

		entry_size = (size_t)number;

		if (entry_size == 0) {

			archive_set_error(&a->archive, EINVAL,

			    "Invalid string table");

			return (ARCHIVE_FATAL);

		}

		if (ar->strtab != NULL) {

			archive_set_error(&a->archive, EINVAL,

			    "More than one string tables exist");

			return (ARCHIVE_FATAL);

		}

		/* Read the filename table into memory. */

		st = malloc(entry_size);

		if (st == NULL) {

			archive_set_error(&a->archive, ENOMEM,

			    "Can't allocate filename table buffer");

			return (ARCHIVE_FATAL);

		}

		ar->strtab = st;

		ar->strtab_size = entry_size;

		if (*unconsumed) {

			__archive_read_consume(a, *unconsumed);

			*unconsumed = 0;

		}

		if ((b = __archive_read_ahead(a, entry_size, NULL)) == NULL)

			return (ARCHIVE_FATAL);

		memcpy(st, b, entry_size);

		__archive_read_consume(a, entry_size);

		/* All contents are consumed. */

		ar->entry_bytes_remaining = 0;

		archive_entry_set_size(entry, ar->entry_bytes_remaining);

		/* Parse the filename table. */

		return (ar_parse_gnu_filename_table(a));

	}

	/*

	 * GNU variant handles long filenames by storing /<number>

	 * to indicate a name stored in the filename table.

	 * XXX TODO: Verify that it's all digits... Don't be fooled

	 * by "/9xyz" XXX

	 */

	if (filename[0] == '/' && filename[1] >= '0' && filename[1] <= '9') {

		number = ar_atol10(h + AR_name_offset + 1, AR_name_size - 1);

		/*

		 * If we can't look up the real name, warn and return

		 * the entry with the wrong name.

		 */

		if (ar->strtab == NULL || number >= ar->strtab_size) {

			archive_set_error(&a->archive, EINVAL,

			    "Can't find long filename for GNU/SVR4 archive entry");

			archive_entry_copy_pathname(entry, filename);

			/* Parse the time, owner, mode, size fields. */

			ar_parse_common_header(ar, entry, h);

			return (ARCHIVE_FATAL);

		}

		archive_entry_copy_pathname(entry, &ar->strtab[(size_t)number]);

		/* Parse the time, owner, mode, size fields. */

		return (ar_parse_common_header(ar, entry, h));

	}

	/*

	 * BSD handles long filenames by storing "#1/" followed by the

	 * length of filename as a decimal number, then prepends the

	 * the filename to the file contents.

	 */

	if (strncmp(filename, "#1/", 3) == 0) {

		/* Parse the time, owner, mode, size fields. */

		/* This must occur before _read_ahead is called again. */

		ar_parse_common_header(ar, entry, h);

		/* Parse the size of the name, adjust the file size. */

		number = ar_atol10(h + AR_name_offset + 3, AR_name_size - 3);

		/* Sanity check the filename length:

		 *   = Must be <= SIZE_MAX - 1

		 *   = Must be <= 1MB

		 *   = Cannot be bigger than the entire entry

		 */

		if (number > SIZE_MAX - 1

		    || number > 1024 * 1024

		    || (int64_t)number > ar->entry_bytes_remaining) {

			archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,

			    "Bad input file size");

			return (ARCHIVE_FATAL);

		}

		bsd_name_length = (size_t)number;

		ar->entry_bytes_remaining -= bsd_name_length;

		/* Adjust file size reported to client. */

		archive_entry_set_size(entry, ar->entry_bytes_remaining);

		if (*unconsumed) {

			__archive_read_consume(a, *unconsumed);

			*unconsumed = 0;

		}

		/* Read the long name into memory. */

		if ((b = __archive_read_ahead(a, bsd_name_length, NULL)) == NULL) {

			archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,

			    "Truncated input file");

			return (ARCHIVE_FATAL);

		}

		/* Store it in the entry. */

		p = (char *)malloc(bsd_name_length + 1);

		if (p == NULL) {

			archive_set_error(&a->archive, ENOMEM,

			    "Can't allocate fname buffer");

			return (ARCHIVE_FATAL);

		}

		strncpy(p, b, bsd_name_length);

		p[bsd_name_length] = '\0';

		__archive_read_consume(a, bsd_name_length);

		archive_entry_copy_pathname(entry, p);

		free(p);

		return (ARCHIVE_OK);

	}

	/*

	 * "/" is the SVR4/GNU archive symbol table.

	 */

	if (strcmp(filename, "/") == 0) {

		archive_entry_copy_pathname(entry, "/");

		/* Parse the time, owner, mode, size fields. */

		r = ar_parse_common_header(ar, entry, h);

		/* Force the file type to a regular file. */

		archive_entry_set_filetype(entry, AE_IFREG);

		return (r);

	}

	/*

	 * "__.SYMDEF" is a BSD archive symbol table.

	 */

	if (strcmp(filename, "__.SYMDEF") == 0) {

		archive_entry_copy_pathname(entry, filename);

		/* Parse the time, owner, mode, size fields. */

		return (ar_parse_common_header(ar, entry, h));

	}

	/*

	 * Otherwise, this is a standard entry.  The filename

	 * has already been trimmed as much as possible, based

	 * on our current knowledge of the format.

	 */

	archive_entry_copy_pathname(entry, filename);

	return (ar_parse_common_header(ar, entry, h));

}

static int

archive_read_format_ar_read_header(struct archive_read *a,

    struct archive_entry *entry)

{

	struct ar *ar = (struct ar*)(a->format->data);

	size_t unconsumed;

	const void *header_data;

	int ret;

	if (!ar->read_global_header) {

		/*

		 * We are now at the beginning of the archive,

		 * so we need first consume the ar global header.

		 */

		__archive_read_consume(a, 8);

		ar->read_global_header = 1;

		/* Set a default format code for now. */

		a->archive.archive_format = ARCHIVE_FORMAT_AR;

	}

	/* Read the header for the next file entry. */

	if ((header_data = __archive_read_ahead(a, 60, NULL)) == NULL)

		/* Broken header. */

		return (ARCHIVE_EOF);

	unconsumed = 60;

	ret = _ar_read_header(a, entry, ar, (const char *)header_data, &unconsumed);

	if (unconsumed)

		__archive_read_consume(a, unconsumed);

	return ret;

}

static int

ar_parse_common_header(struct ar *ar, struct archive_entry *entry,

    const char *h)

{

	uint64_t n;

	/* Copy remaining header */

	archive_entry_set_mtime(entry,

	    (time_t)ar_atol10(h + AR_date_offset, AR_date_size), 0L);

	archive_entry_set_uid(entry,

	    (uid_t)ar_atol10(h + AR_uid_offset, AR_uid_size));

	archive_entry_set_gid(entry,

	    (gid_t)ar_atol10(h + AR_gid_offset, AR_gid_size));

	archive_entry_set_mode(entry,

	    (mode_t)ar_atol8(h + AR_mode_offset, AR_mode_size));

	n = ar_atol10(h + AR_size_offset, AR_size_size);

	ar->entry_offset = 0;

	ar->entry_padding = n % 2;

	archive_entry_set_size(entry, n);

	ar->entry_bytes_remaining = n;

	return (ARCHIVE_OK);

}

static int

archive_read_format_ar_read_data(struct archive_read *a,

    const void **buff, size_t *size, int64_t *offset)

{

	ssize_t bytes_read;

	struct ar *ar;

	ar = (struct ar *)(a->format->data);

	if (ar->entry_bytes_unconsumed) {

		__archive_read_consume(a, ar->entry_bytes_unconsumed);

		ar->entry_bytes_unconsumed = 0;

	}

	if (ar->entry_bytes_remaining > 0) {

		*buff = __archive_read_ahead(a, 1, &bytes_read);

		if (bytes_read == 0) {

			archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,

			    "Truncated ar archive");

			return (ARCHIVE_FATAL);

		}

		if (bytes_read < 0)

			return (ARCHIVE_FATAL);

		if (bytes_read > ar->entry_bytes_remaining)

			bytes_read = (ssize_t)ar->entry_bytes_remaining;

		*size = bytes_read;

		ar->entry_bytes_unconsumed = bytes_read;

		*offset = ar->entry_offset;

		ar->entry_offset += bytes_read;

		ar->entry_bytes_remaining -= bytes_read;

		return (ARCHIVE_OK);

	} else {

		int64_t skipped = __archive_read_consume(a, ar->entry_padding);

		if (skipped >= 0) {

			ar->entry_padding -= skipped;

		}

		if (ar->entry_padding) {

			if (skipped >= 0) {

				archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,

					"Truncated ar archive- failed consuming padding");

			}

			return (ARCHIVE_FATAL);

		}

		*buff = NULL;

		*size = 0;

		*offset = ar->entry_offset;

		return (ARCHIVE_EOF);

	}

}

static int

archive_read_format_ar_skip(struct archive_read *a)

{

	int64_t bytes_skipped;

	struct ar* ar;

	ar = (struct ar *)(a->format->data);

	bytes_skipped = __archive_read_consume(a,

	    ar->entry_bytes_remaining + ar->entry_padding

	    + ar->entry_bytes_unconsumed);

	if (bytes_skipped < 0)

		return (ARCHIVE_FATAL);

	ar->entry_bytes_remaining = 0;

	ar->entry_bytes_unconsumed = 0;

	ar->entry_padding = 0;

	return (ARCHIVE_OK);

}

static int

ar_parse_gnu_filename_table(struct archive_read *a)

{

	struct ar *ar;

	char *p;

	size_t size;

	ar = (struct ar*)(a->format->data);

	size = ar->strtab_size;

	for (p = ar->strtab; p < ar->strtab + size - 1; ++p) {

		if (*p == '/') {

			*p++ = '\0';

			if (*p != '\n')

				goto bad_string_table;

			*p = '\0';

		}

	}

	/*

	 * GNU ar always pads the table to an even size.

	 * The pad character is either '\n' or '`'.

	 */

	if (p != ar->strtab + size && *p != '\n' && *p != '`')

		goto bad_string_table;

	/* Enforce zero termination. */

	ar->strtab[size - 1] = '\0';

	return (ARCHIVE_OK);

bad_string_table:

	archive_set_error(&a->archive, EINVAL,

	    "Invalid string table");

	free(ar->strtab);

	ar->strtab = NULL;

	return (ARCHIVE_FATAL);

}

static uint64_t

ar_atol8(const char *p, unsigned char_cnt)

{

	uint64_t l, limit, last_digit_limit;

	unsigned int digit, base;

	base = 8;

	limit = UINT64_MAX / base;

	last_digit_limit = UINT64_MAX % base;

	while ((*p == ' ' || *p == '\t') && char_cnt-- > 0)

		p++;

	l = 0;

	digit = *p - '0';

	while (*p >= '0' && digit < base  && char_cnt-- > 0) {

		if (l>limit || (l == limit && digit > last_digit_limit)) {

			l = UINT64_MAX; /* Truncate on overflow. */

			break;

		}

		l = (l * base) + digit;

		digit = *++p - '0';

	}

	return (l);

}

static uint64_t

ar_atol10(const char *p, unsigned char_cnt)

{

	uint64_t l, limit, last_digit_limit;

	unsigned int base, digit;

	base = 10;

	limit = UINT64_MAX / base;

	last_digit_limit = UINT64_MAX % base;

	while ((*p == ' ' || *p == '\t') && char_cnt-- > 0)

		p++;

	l = 0;

	digit = *p - '0';

	while (*p >= '0' && digit < base  && char_cnt-- > 0) {

		if (l > limit || (l == limit && digit > last_digit_limit)) {

			l = UINT64_MAX; /* Truncate on overflow. */

			break;

		}

		l = (l * base) + digit;

		digit = *++p - '0';

	}

	return (l);

}