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pax: fix typos in comments in file_subs.c & tar.c

Stamp out "greengrocers' apostrophes" in various places (arguably there
are still more present, but style guides vary on that, and my energies
spent corralling wayward punctuation marks could be spent elsewhere).

/*	$NetBSD: tar.c,v 1.75 2019/03/20 03:13:39 gutteridge Exp $	*/

/*-
 * Copyright (c) 1992 Keith Muller.
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Keith Muller of the University of California, San Diego.
 *
 * 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
 */

#if HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
#endif

#include <sys/cdefs.h>
#if !defined(lint)
#if 0
static char sccsid[] = "@(#)tar.c	8.2 (Berkeley) 4/18/94";
#else
__RCSID("$NetBSD: tar.c,v 1.75 2019/03/20 03:13:39 gutteridge Exp $");
#endif
#endif /* not lint */

#include <sys/types.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/param.h>

#include <ctype.h>
#include <errno.h>
#include <grp.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "pax.h"
#include "extern.h"
#include "tar.h"

extern struct stat tst;

/*
 * Routines for reading, writing and header identify of various versions of tar
 */

static int expandname(char *, size_t,  char **, size_t *, const char *, size_t);
static void longlink(ARCHD *, int);
static uint32_t tar_chksm(char *, int);
static char *name_split(char *, int);
static int u32_oct(uintmax_t, char *, int, int);
static int umax_oct(uintmax_t, char *, int, int);
static int tar_gnutar_exclude_one(const char *, size_t);
static int check_sum(char *, size_t, char *, size_t, int);

/*
 * Routines common to all versions of tar
 */

static int tar_nodir;			/* do not write dirs under old tar */
int is_gnutar;				/* behave like gnu tar; enable gnu
					 * extensions and skip end-of-volume
					 * checks
					 */
static int seen_gnu_warning;		/* Have we warned yet? */
static char *gnu_hack_string;		/* ././@LongLink hackery */
static int gnu_hack_len;		/* len of gnu_hack_string */
char *gnu_name_string;			/* ././@LongLink hackery name */
char *gnu_link_string;			/* ././@LongLink hackery link */
size_t gnu_name_length;			/* ././@LongLink hackery name */
size_t gnu_link_length;			/* ././@LongLink hackery link */
static int gnu_short_trailer;		/* gnu short trailer */

static const char LONG_LINK[] = "././@LongLink";

#ifdef _PAX_
char DEV_0[] = "/dev/rst0";
char DEV_1[] = "/dev/rst1";
char DEV_4[] = "/dev/rst4";
char DEV_5[] = "/dev/rst5";
char DEV_7[] = "/dev/rst7";
char DEV_8[] = "/dev/rst8";
#endif

static int
check_sum(char *hd, size_t hdlen, char *bl, size_t bllen, int quiet)
{
	uint32_t hdck, blck;

	hdck = asc_u32(hd, hdlen, OCT);
	blck = tar_chksm(bl, bllen);

	if (hdck != blck) {
		if (!quiet)
			tty_warn(0, "Header checksum %o does not match %o",
			    hdck, blck);
		return -1;
	}
	return 0;
}


/*
 * tar_endwr()
 *	add the tar trailer of two null blocks
 * Return:
 *	0 if ok, -1 otherwise (what wr_skip returns)
 */

int
tar_endwr(void)
{
	return wr_skip((off_t)(NULLCNT * BLKMULT));
}

/*
 * tar_endrd()
 *	no cleanup needed here, just return size of trailer (for append)
 * Return:
 *	size of trailer BLKMULT
 */

off_t
tar_endrd(void)
{
	return (off_t)((gnu_short_trailer ? 1 : NULLCNT) * BLKMULT);
}

/*
 * tar_trail()
 *	Called to determine if a header block is a valid trailer. We are passed
 *	the block, the in_sync flag (which tells us we are in resync mode;
 *	looking for a valid header), and cnt (which starts at zero) which is
 *	used to count the number of empty blocks we have seen so far.
 * Return:
 *	0 if a valid trailer, -1 if not a valid trailer, or 1 if the block
 *	could never contain a header.
 */

int
tar_trail(char *buf, int in_resync, int *cnt)
{
	int i;

	gnu_short_trailer = 0;
	/*
	 * look for all zero, trailer is two consecutive blocks of zero
	 */
	for (i = 0; i < BLKMULT; ++i) {
		if (buf[i] != '\0')
			break;
	}

	/*
	 * if not all zero it is not a trailer, but MIGHT be a header.
	 */
	if (i != BLKMULT)
		return -1;

	/*
	 * When given a zero block, we must be careful!
	 * If we are not in resync mode, check for the trailer. Have to watch
	 * out that we do not mis-identify file data as the trailer, so we do
	 * NOT try to id a trailer during resync mode. During resync mode we
	 * might as well throw this block out since a valid header can NEVER be
	 * a block of all 0 (we must have a valid file name).
	 */
	if (!in_resync) {
		++*cnt;
		/*
		 * old GNU tar (up through 1.13) only writes one block of
		 * trailers, so we pretend we got another
		 */
		if (is_gnutar) {
			gnu_short_trailer = 1;
			++*cnt;
		}
		if (*cnt >= NULLCNT)
			return 0;
	}
	return 1;
}

/*
 * u32_oct()
 *	convert an uintmax_t to an octal string. many oddball field
 *	termination characters are used by the various versions of tar in the
 *	different fields. term selects which kind to use. str is '0' padded
 *	at the front to len. we are unable to use only one format as many old
 *	tar readers are very cranky about this.
 * Return:
 *	0 if the number fit into the string, -1 otherwise
 */

static int
u32_oct(uintmax_t val, char *str, int len, int term)
{
	char *pt;
	uint64_t p;

	p = val & TOP_HALF;
	if (p && p != TOP_HALF)
		return -1;

	val &= BOTTOM_HALF;

	/*
	 * term selects the appropriate character(s) for the end of the string
	 */
	pt = str + len - 1;
	switch(term) {
	case 3:
		*pt-- = '\0';
		break;
	case 2:
		*pt-- = ' ';
		*pt-- = '\0';
		break;
	case 1:
		*pt-- = ' ';
		break;
	case 0:
	default:
		*pt-- = '\0';
		*pt-- = ' ';
		break;
	}

	/*
	 * convert and blank pad if there is space
	 */
	while (pt >= str) {
		*pt-- = '0' + (char)(val & 0x7);
		if ((val = val >> 3) == 0)
			break;
	}

	while (pt >= str)
		*pt-- = '0';
	if (val != 0)
		return -1;
	return 0;
}

/*
 * umax_oct()
 *	convert an unsigned long long to an octal string. one of many oddball
 *	field termination characters are used by the various versions of tar
 *	in the different fields. term selects which kind to use. str is '0'
 *	padded at the front to len. we are unable to use only one format as
 *	many old tar readers are very cranky about this.
 * Return:
 *	0 if the number fit into the string, -1 otherwise
 */

static int
umax_oct(uintmax_t val, char *str, int len, int term)
{
	char *pt;

	/*
	 * term selects the appropriate character(s) for the end of the string
	 */
	pt = str + len - 1;
	switch(term) {
	case 3:
		*pt-- = '\0';
		break;
	case 2:
		*pt-- = ' ';
		*pt-- = '\0';
		break;
	case 1:
		*pt-- = ' ';
		break;
	case 0:
	default:
		*pt-- = '\0';
		*pt-- = ' ';
		break;
	}

	/*
	 * convert and blank pad if there is space
	 */
	while (pt >= str) {
		*pt-- = '0' + (char)(val & 0x7);
		if ((val = val >> 3) == 0)
			break;
	}

	while (pt >= str)
		*pt-- = '0';
	if (val != 0)
		return -1;
	return 0;
}

/*
 * tar_chksm()
 *	calculate the checksum for a tar block counting the checksum field as
 *	all blanks (BLNKSUM is that value pre-calculated, the sum of 8 blanks).
 *	NOTE: we use len to short circuit summing 0's on write since we ALWAYS
 *	pad headers with 0.
 * Return:
 *	unsigned long checksum
 */

static uint32_t
tar_chksm(char *blk, int len)
{
	char *stop;
	char *pt;
	uint32_t chksm = BLNKSUM;	/* initial value is checksum field sum */

	/*
	 * add the part of the block before the checksum field
	 */
	pt = blk;
	stop = blk + CHK_OFFSET;
	while (pt < stop)
		chksm += (uint32_t)(*pt++ & 0xff);
	/*
	 * move past the checksum field and keep going, spec counts the
	 * checksum field as the sum of 8 blanks (which is pre-computed as
	 * BLNKSUM).
	 * ASSUMED: len is greater than CHK_OFFSET. (len is where our 0 padding
	 * starts, no point in summing zeros)
	 */
	pt += CHK_LEN;
	stop = blk + len;
	while (pt < stop)
		chksm += (uint32_t)(*pt++ & 0xff);
	return chksm;
}

/*
 * Routines for old BSD style tar (also made portable to sysV tar)
 */

/*
 * tar_id()
 *	determine if a block given to us is a valid tar header (and not a USTAR
 *	header). We have to be on the lookout for those pesky blocks of	all
 *	zeros.
 * Return:
 *	0 if a tar header, -1 otherwise
 */

int
tar_id(char *blk, int size)
{
	HD_TAR *hd;
	HD_USTAR *uhd;
	static int is_ustar = -1;

	if (size < BLKMULT)
		return -1;
	hd = (HD_TAR *)blk;
	uhd = (HD_USTAR *)blk;

	/*
	 * check for block of zeros first, a simple and fast test, then make
	 * sure this is not a ustar header by looking for the ustar magic
	 * cookie. We should use TMAGLEN, but some USTAR archive programs are
	 * wrong and create archives missing the \0. Last we check the
	 * checksum. If this is ok we have to assume it is a valid header.
	 */
	if (hd->name[0] == '\0')
		return -1;
	if (strncmp(uhd->magic, TMAGIC, TMAGLEN - 1) == 0) {
		if (is_ustar == -1) {
			is_ustar = 1;
			return -1;
		} else
			tty_warn(0,
			    "Busted tar archive: has both ustar and old tar "
			    "records");
	} else
		is_ustar = 0; 
	return check_sum(hd->chksum, sizeof(hd->chksum), blk, BLKMULT, 1);
}

/*
 * tar_opt()
 *	handle tar format specific -o options
 * Return:
 *	0 if ok -1 otherwise
 */

int
tar_opt(void)
{
	OPLIST *opt;

	while ((opt = opt_next()) != NULL) {
		if (strcmp(opt->name, TAR_OPTION) ||
		    strcmp(opt->value, TAR_NODIR)) {
			tty_warn(1,
			    "Unknown tar format -o option/value pair %s=%s",
			    opt->name, opt->value);
			tty_warn(1,
			    "%s=%s is the only supported tar format option",
			    TAR_OPTION, TAR_NODIR);
			return -1;
		}

		/*
		 * we only support one option, and only when writing
		 */
		if ((act != APPND) && (act != ARCHIVE)) {
			tty_warn(1, "%s=%s is only supported when writing.",
			    opt->name, opt->value);
			return -1;
		}
		tar_nodir = 1;
	}
	return 0;
}


/*
 * tar_rd()
 *	extract the values out of block already determined to be a tar header.
 *	store the values in the ARCHD parameter.
 * Return:
 *	0
 */

int
tar_rd(ARCHD *arcn, char *buf)
{
	HD_TAR *hd;
	char *pt;

	/*
	 * we only get proper sized buffers passed to us
	 */
	if (tar_id(buf, BLKMULT) < 0)
		return -1;
	memset(arcn, 0, sizeof(*arcn));
	arcn->org_name = arcn->name;
	arcn->pat = NULL;
	arcn->sb.st_nlink = 1;

	/*
	 * copy out the name and values in the stat buffer
	 */
	hd = (HD_TAR *)buf;
	if (hd->linkflag != LONGLINKTYPE && hd->linkflag != LONGNAMETYPE) {
		arcn->nlen = expandname(arcn->name, sizeof(arcn->name),
		    &gnu_name_string, &gnu_name_length, hd->name,
		    sizeof(hd->name));
		arcn->ln_nlen = expandname(arcn->ln_name, sizeof(arcn->ln_name),
		    &gnu_link_string, &gnu_link_length, hd->linkname,
		    sizeof(hd->linkname));
	}
	arcn->sb.st_mode = (mode_t)(asc_u32(hd->mode,sizeof(hd->mode),OCT) &
	    0xfff);
	arcn->sb.st_uid = (uid_t)asc_u32(hd->uid, sizeof(hd->uid), OCT);
	arcn->sb.st_gid = (gid_t)asc_u32(hd->gid, sizeof(hd->gid), OCT);
	arcn->sb.st_size = (off_t)ASC_OFFT(hd->size, sizeof(hd->size), OCT);
	if (arcn->sb.st_size == -1)
		return -1;
	arcn->sb.st_mtime = (time_t)(int32_t)asc_u32(hd->mtime, sizeof(hd->mtime), OCT);
	arcn->sb.st_ctime = arcn->sb.st_atime = arcn->sb.st_mtime;

	/*
	 * have to look at the last character, it may be a '/' and that is used
	 * to encode this as a directory
	 */
	pt = &(arcn->name[arcn->nlen - 1]);
	arcn->pad = 0;
	arcn->skip = 0;
	switch(hd->linkflag) {
	case SYMTYPE:
		/*
		 * symbolic link, need to get the link name and set the type in
		 * the st_mode so -v printing will look correct.
		 */
		arcn->type = PAX_SLK;
		arcn->sb.st_mode |= S_IFLNK;
		break;
	case LNKTYPE:
		/*
		 * hard link, need to get the link name, set the type in the
		 * st_mode and st_nlink so -v printing will look better.
		 */
		arcn->type = PAX_HLK;
		arcn->sb.st_nlink = 2;

		/*
		 * no idea of what type this thing really points at, but
		 * we set something for printing only.
		 */
		arcn->sb.st_mode |= S_IFREG;
		break;
	case LONGLINKTYPE:
	case LONGNAMETYPE:
		/*
		 * GNU long link/file; we tag these here and let the
		 * pax internals deal with it -- too ugly otherwise.
		 */
		if (hd->linkflag != LONGLINKTYPE)
			arcn->type = PAX_GLF;
		else
			arcn->type = PAX_GLL;
		arcn->pad = TAR_PAD(arcn->sb.st_size);
		arcn->skip = arcn->sb.st_size;
		break;
	case AREGTYPE:
	case REGTYPE:
	case DIRTYPE:	/* see below */
	default:
		/*
		 * If we have a trailing / this is a directory and NOT a file.
		 * Note: V7 tar doesn't actually have DIRTYPE, but it was
		 * reported that V7 archives using USTAR directories do exist.
		 */
		if (*pt == '/' || hd->linkflag == DIRTYPE) {
			/*
			 * it is a directory, set the mode for -v printing
			 */
			arcn->type = PAX_DIR;
			arcn->sb.st_mode |= S_IFDIR;
			arcn->sb.st_nlink = 2;
		} else {
			/*
			 * have a file that will be followed by data. Set the
			 * skip value to the size field and calculate the size
			 * of the padding.
			 */
			arcn->type = PAX_REG;
			arcn->sb.st_mode |= S_IFREG;
			arcn->pad = TAR_PAD(arcn->sb.st_size);
			arcn->skip = arcn->sb.st_size;
		}
		break;
	}

	/*
	 * strip off any trailing slash.
	 */
	if (*pt == '/') {
		*pt = '\0';
		--arcn->nlen;
	}
	return 0;
}

/*
 * tar_wr()
 *	write a tar header for the file specified in the ARCHD to the archive.
 *	Have to check for file types that cannot be stored and file names that
 *	are too long. Be careful of the term (last arg) to u32_oct, each field
 *	of tar has it own spec for the termination character(s).
 *	ASSUMED: space after header in header block is zero filled
 * Return:
 *	0 if file has data to be written after the header, 1 if file has NO
 *	data to write after the header, -1 if archive write failed
 */

int
tar_wr(ARCHD *arcn)
{
	HD_TAR *hd;
	int len;
	uintmax_t mtime;
	char hdblk[sizeof(HD_TAR)];

	/*
	 * check for those file system types which tar cannot store
	 */
	switch(arcn->type) {
	case PAX_DIR:
		/*
		 * user asked that dirs not be written to the archive
		 */
		if (tar_nodir)
			return 1;
		break;
	case PAX_CHR:
		tty_warn(1, "Tar cannot archive a character device %s",
		    arcn->org_name);
		return 1;
	case PAX_BLK:
		tty_warn(1,
		    "Tar cannot archive a block device %s", arcn->org_name);
		return 1;
	case PAX_SCK:
		tty_warn(1, "Tar cannot archive a socket %s", arcn->org_name);
		return 1;
	case PAX_FIF:
		tty_warn(1, "Tar cannot archive a fifo %s", arcn->org_name);
		return 1;
	case PAX_SLK:
	case PAX_HLK:
	case PAX_HRG:
		if (arcn->ln_nlen > (int)sizeof(hd->linkname)) {
			tty_warn(1,"Link name too long for tar %s",
			    arcn->ln_name);
			return 1;
		}
		break;
	case PAX_REG:
	case PAX_CTG:
	default:
		break;
	}

	/*
	 * check file name len, remember extra char for dirs (the / at the end)
	 */
	len = arcn->nlen;
	if (arcn->type == PAX_DIR)
		++len;
	if (len >= (int)sizeof(hd->name)) {
		tty_warn(1, "File name too long for tar %s", arcn->name);
		return 1;
	}

	/*
	 * copy the data out of the ARCHD into the tar header based on the type
	 * of the file. Remember many tar readers want the unused fields to be
	 * padded with zero. We set the linkflag field (type), the linkname
	 * (or zero if not used),the size, and set the padding (if any) to be
	 * added after the file data (0 for all other types, as they only have
	 * a header)
	 */
	memset(hdblk, 0, sizeof(hdblk));
	hd = (HD_TAR *)hdblk;
	strlcpy(hd->name, arcn->name, sizeof(hd->name));
	arcn->pad = 0;

	if (arcn->type == PAX_DIR) {
		/*
		 * directories are the same as files, except have a filename
		 * that ends with a /, we add the slash here. No data follows,
		 * dirs, so no pad.
		 */
		hd->linkflag = AREGTYPE;
		hd->name[len-1] = '/';
		if (u32_oct((uintmax_t)0L, hd->size, sizeof(hd->size), 1))
			goto out;
	} else if (arcn->type == PAX_SLK) {
		/*
		 * no data follows this file, so no pad
		 */
		hd->linkflag = SYMTYPE;
		strlcpy(hd->linkname, arcn->ln_name, sizeof(hd->linkname));
		if (u32_oct((uintmax_t)0L, hd->size, sizeof(hd->size), 1))
			goto out;
	} else if ((arcn->type == PAX_HLK) || (arcn->type == PAX_HRG)) {
		/*
		 * no data follows this file, so no pad
		 */
		hd->linkflag = LNKTYPE;
		strlcpy(hd->linkname, arcn->ln_name, sizeof(hd->linkname));
		if (u32_oct((uintmax_t)0L, hd->size, sizeof(hd->size), 1))
			goto out;
	} else {
		/*
		 * data follows this file, so set the pad
		 */
		hd->linkflag = AREGTYPE;
		if (OFFT_OCT(arcn->sb.st_size, hd->size, sizeof(hd->size), 1)) {
			tty_warn(1,"File is too large for tar %s",
			    arcn->org_name);
			return 1;
		}
		arcn->pad = TAR_PAD(arcn->sb.st_size);
	}

	/*
	 * copy those fields that are independent of the type
	 */
	mtime = tst.st_ino ? tst.st_mtime : arcn->sb.st_mtime;
	if (u32_oct((uintmax_t)arcn->sb.st_mode, hd->mode, sizeof(hd->mode), 0) ||
	    u32_oct((uintmax_t)arcn->sb.st_uid, hd->uid, sizeof(hd->uid), 0) ||
	    u32_oct((uintmax_t)arcn->sb.st_gid, hd->gid, sizeof(hd->gid), 0) ||
	    u32_oct(mtime, hd->mtime, sizeof(hd->mtime), 1))
		goto out;

	/*
	 * calculate and add the checksum, then write the header. A return of
	 * 0 tells the caller to now write the file data, 1 says no data needs
	 * to be written
	 */
	if (u32_oct(tar_chksm(hdblk, sizeof(HD_TAR)), hd->chksum,
	    sizeof(hd->chksum), 3))
		goto out;			/* XXX Something's wrong here
						 * because a zero-byte file can
						 * cause this to be done and
						 * yet the resulting warning
						 * seems incorrect */

	if (wr_rdbuf(hdblk, sizeof(HD_TAR)) < 0)
		return -1;
	if (wr_skip((off_t)(BLKMULT - sizeof(HD_TAR))) < 0)
		return -1;
	if ((arcn->type == PAX_CTG) || (arcn->type == PAX_REG))
		return 0;
	return 1;

    out:
	/*
	 * header field is out of range
	 */
	tty_warn(1, "Tar header field is too small for %s", arcn->org_name);
	return 1;
}

/*
 * Routines for POSIX ustar
 */

/*
 * ustar_strd()
 *	initialization for ustar read
 * Return:
 *	0 if ok, -1 otherwise
 */

int
ustar_strd(void)
{
	return 0;
}

/*
 * ustar_stwr()
 *	initialization for ustar write
 * Return:
 *	0 if ok, -1 otherwise
 */

int
ustar_stwr(void)
{
	return 0;
}

/*
 * ustar_id()
 *	determine if a block given to us is a valid ustar header. We have to
 *	be on the lookout for those pesky blocks of all zeros
 * Return:
 *	0 if a ustar header, -1 otherwise
 */

int
ustar_id(char *blk, int size)
{
	HD_USTAR *hd;

	if (size < BLKMULT)
		return -1;
	hd = (HD_USTAR *)blk;

	/*
	 * check for block of zeros first, a simple and fast test then check
	 * ustar magic cookie. We should use TMAGLEN, but some USTAR archive
	 * programs are fouled up and create archives missing the \0. Last we
	 * check the checksum. If ok we have to assume it is a valid header.
	 */
	if (hd->name[0] == '\0')
		return -1;
	if (strncmp(hd->magic, TMAGIC, TMAGLEN - 1) != 0)
		return -1;
	/* This is GNU tar */
	if (strncmp(hd->magic, "ustar  ", 8) == 0 && !is_gnutar &&
	    !seen_gnu_warning) {
		seen_gnu_warning = 1;
		tty_warn(0,
		    "Trying to read GNU tar archive with GNU extensions and end-of-volume checks off");
	}
	return check_sum(hd->chksum, sizeof(hd->chksum), blk, BLKMULT, 0);
}

/*
 * ustar_rd()
 *	extract the values out of block already determined to be a ustar header.
 *	store the values in the ARCHD parameter.
 * Return:
 *	0
 */

int
ustar_rd(ARCHD *arcn, char *buf)
{
	HD_USTAR *hd;
	char *dest;
	int cnt;
	dev_t devmajor;
	dev_t devminor;

	/*
	 * we only get proper sized buffers
	 */
	if (ustar_id(buf, BLKMULT) < 0)
		return -1;

	memset(arcn, 0, sizeof(*arcn));
	arcn->org_name = arcn->name;
	arcn->pat = NULL;
	arcn->sb.st_nlink = 1;
	hd = (HD_USTAR *)buf;

	/*
	 * see if the filename is split into two parts. if, so joint the parts.
	 * we copy the prefix first and add a / between the prefix and name.
	 */
	dest = arcn->name;
	if (*(hd->prefix) != '\0') {
		cnt = strlcpy(arcn->name, hd->prefix, sizeof(arcn->name));
		dest += cnt;
		*dest++ = '/';
		cnt++;
	} else {
		cnt = 0;
	}

	if (hd->typeflag != LONGLINKTYPE && hd->typeflag != LONGNAMETYPE) {
		arcn->nlen = expandname(dest, sizeof(arcn->name) - cnt,
		    &gnu_name_string, &gnu_name_length, hd->name,
		    sizeof(hd->name)) + cnt;
		arcn->ln_nlen = expandname(arcn->ln_name,
		    sizeof(arcn->ln_name), &gnu_link_string, &gnu_link_length,
		    hd->linkname, sizeof(hd->linkname));
	}

	/*
	 * follow the spec to the letter. we should only have mode bits, strip
	 * off all other crud we may be passed.
	 */
	arcn->sb.st_mode = (mode_t)(asc_u32(hd->mode, sizeof(hd->mode), OCT) &
	    0xfff);
	arcn->sb.st_size = (off_t)ASC_OFFT(hd->size, sizeof(hd->size), OCT);
	if (arcn->sb.st_size == -1)
		return -1;
	arcn->sb.st_mtime = (time_t)(int32_t)asc_u32(hd->mtime, sizeof(hd->mtime), OCT);
	arcn->sb.st_ctime = arcn->sb.st_atime = arcn->sb.st_mtime;

	/*
	 * If we can find the ascii names for gname and uname in the password
	 * and group files we will use the uid's and gid they bind. Otherwise
	 * we use the uid and gid values stored in the header. (This is what
	 * the posix spec wants).
	 */
	hd->gname[sizeof(hd->gname) - 1] = '\0';
	if (gid_from_group(hd->gname, &(arcn->sb.st_gid)) < 0)
		arcn->sb.st_gid = (gid_t)asc_u32(hd->gid, sizeof(hd->gid), OCT);
	hd->uname[sizeof(hd->uname) - 1] = '\0';
	if (uid_from_user(hd->uname, &(arcn->sb.st_uid)) < 0)
		arcn->sb.st_uid = (uid_t)asc_u32(hd->uid, sizeof(hd->uid), OCT);

	/*
	 * set the defaults, these may be changed depending on the file type
	 */
	arcn->pad = 0;
	arcn->skip = 0;
	arcn->sb.st_rdev = (dev_t)0;

	/*
	 * set the mode and PAX type according to the typeflag in the header
	 */
	switch(hd->typeflag) {
	case FIFOTYPE:
		arcn->type = PAX_FIF;
		arcn->sb.st_mode |= S_IFIFO;
		break;
	case DIRTYPE:
		arcn->type = PAX_DIR;
		arcn->sb.st_mode |= S_IFDIR;
		arcn->sb.st_nlink = 2;

		/*
		 * Some programs that create ustar archives append a '/'
		 * to the pathname for directories. This clearly violates
		 * ustar specs, but we will silently strip it off anyway.
		 */
		if (arcn->name[arcn->nlen - 1] == '/')
			arcn->name[--arcn->nlen] = '\0';
		break;
	case BLKTYPE:
	case CHRTYPE:
		/*
		 * this type requires the rdev field to be set.
		 */
		if (hd->typeflag == BLKTYPE) {
			arcn->type = PAX_BLK;
			arcn->sb.st_mode |= S_IFBLK;
		} else {
			arcn->type = PAX_CHR;
			arcn->sb.st_mode |= S_IFCHR;
		}
		devmajor = (dev_t)asc_u32(hd->devmajor,sizeof(hd->devmajor),OCT);
		devminor = (dev_t)asc_u32(hd->devminor,sizeof(hd->devminor),OCT);
		arcn->sb.st_rdev = TODEV(devmajor, devminor);
		break;
	case SYMTYPE:
	case LNKTYPE:
		if (hd->typeflag == SYMTYPE) {
			arcn->type = PAX_SLK;
			arcn->sb.st_mode |= S_IFLNK;
		} else {
			arcn->type = PAX_HLK;
			/*
			 * so printing looks better
			 */
			arcn->sb.st_mode |= S_IFREG;
			arcn->sb.st_nlink = 2;
		}
		break;
	case LONGLINKTYPE:
	case LONGNAMETYPE:
		if (is_gnutar) {
			/*
			 * GNU long link/file; we tag these here and let the
			 * pax internals deal with it -- too ugly otherwise.
			 */
			if (hd->typeflag != LONGLINKTYPE)
				arcn->type = PAX_GLF;
			else
				arcn->type = PAX_GLL;
			arcn->pad = TAR_PAD(arcn->sb.st_size);
			arcn->skip = arcn->sb.st_size;
		} else {
			tty_warn(1, "GNU Long %s found in posix ustar archive.",
			    hd->typeflag == LONGLINKTYPE ? "Link" : "File");
		}
		break;
	case FILEXTYPE:
	case GLOBXTYPE:
		    tty_warn(0, "%s extended headers posix ustar archive."
		    " Extracting as plain files. Following files might be"
		    " in the wrong directory or have wrong attributes.",
			hd->typeflag == FILEXTYPE ? "File" : "Global");
		    /*FALLTHROUGH*/
	case CONTTYPE:
	case AREGTYPE:
	case REGTYPE:
	default:
		/*
		 * these types have file data that follows. Set the skip and
		 * pad fields.
		 */
		arcn->type = PAX_REG;
		arcn->pad = TAR_PAD(arcn->sb.st_size);
		arcn->skip = arcn->sb.st_size;
		arcn->sb.st_mode |= S_IFREG;
		break;
	}
	return 0;
}

static int
expandname(char *buf, size_t len, char **gnu_name, size_t *gnu_length,
    const char *name, size_t nlen)
{
	if (*gnu_name) {
		len = strlcpy(buf, *gnu_name, len);
		free(*gnu_name);
		*gnu_name = NULL;
		*gnu_length = 0;
	} else {
		if (len > ++nlen)
			len = nlen;
		len = strlcpy(buf, name, len);
	}
	return len;
}

static void
longlink(ARCHD *arcn, int type)
{
	ARCHD larc;

	(void)memset(&larc, 0, sizeof(larc));

	larc.type = type;
	larc.nlen = strlcpy(larc.name, LONG_LINK, sizeof(larc.name));

	switch (type) {
	case PAX_GLL:
		gnu_hack_string = arcn->ln_name;
		gnu_hack_len = arcn->ln_nlen + 1;
		break;
	case PAX_GLF:
		gnu_hack_string = arcn->name;
		gnu_hack_len = arcn->nlen + 1;
		break;
	default:
		errx(1, "Invalid type in GNU longlink %d", type);
	}

	/*
	 * We need a longlink now.
	 */
	ustar_wr(&larc);
}

/*
 * ustar_wr()
 *	write a ustar header for the file specified in the ARCHD to the archive
 *	Have to check for file types that cannot be stored and file names that
 *	are too long. Be careful of the term (last arg) to u32_oct, we only use
 *	'\0' for the termination character (this is different than picky tar)
 *	ASSUMED: space after header in header block is zero filled
 * Return:
 *	0 if file has data to be written after the header, 1 if file has NO
 *	data to write after the header, -1 if archive write failed
 */

static int
size_err(const char *what, ARCHD *arcn)
{
	/*
	 * header field is out of range
	 */
	tty_warn(1, "Ustar %s header field is too small for %s",
		what, arcn->org_name);
	return 1;
}

int
ustar_wr(ARCHD *arcn)
{
	HD_USTAR *hd;
	char *pt;
	uintmax_t mtime;
	char hdblk[sizeof(HD_USTAR)];
	const char *user, *group;

	switch (arcn->type) {
	case PAX_SCK:
		/*
		 * check for those file system types ustar cannot store
		 */
		if (!is_gnutar)
			tty_warn(1, "Ustar cannot archive a socket %s",
			    arcn->org_name);
		return 1;

	case PAX_SLK:
	case PAX_HLK:
	case PAX_HRG:
		/*
		 * check the length of the linkname
		 */
		if (arcn->ln_nlen >= (int)sizeof(hd->linkname)) {
			if (is_gnutar) {
				longlink(arcn, PAX_GLL);
			} else {
				tty_warn(1, "Link name too long for ustar %s",
				    arcn->ln_name);
				return 1;
			}
		}
		break;
	default:
		break;
	}

	/*
	 * split the path name into prefix and name fields (if needed). if
	 * pt != arcn->name, the name has to be split
	 */
	if ((pt = name_split(arcn->name, arcn->nlen)) == NULL) {
		if (is_gnutar) {
			longlink(arcn, PAX_GLF);
			pt = arcn->name;
		} else {
			tty_warn(1, "File name too long for ustar %s",
			    arcn->name);
			return 1;
		}
	}

	/*
	 * zero out the header so we don't have to worry about zero fill below
	 */
	memset(hdblk, 0, sizeof(hdblk));
	hd = (HD_USTAR *)hdblk;
	arcn->pad = 0L;

	/*
	 * split the name, or zero out the prefix
	 */
	if (pt != arcn->name) {
		/*
		 * name was split, pt points at the / where the split is to
		 * occur, we remove the / and copy the first part to the prefix
		 */
		*pt = '\0';
		strlcpy(hd->prefix, arcn->name, sizeof(hd->prefix));
		*pt++ = '/';
	}

	/*
	 * copy the name part. this may be the whole path or the part after
	 * the prefix
	 */
	strlcpy(hd->name, pt, sizeof(hd->name));

	/*
	 * set the fields in the header that are type dependent
	 */
	switch(arcn->type) {
	case PAX_DIR:
		hd->typeflag = DIRTYPE;
		if (u32_oct((uintmax_t)0L, hd->size, sizeof(hd->size), 3))
			return size_err("DIRTYPE", arcn);
		break;
	case PAX_CHR:
	case PAX_BLK:
		if (arcn->type == PAX_CHR)
			hd->typeflag = CHRTYPE;
		else
			hd->typeflag = BLKTYPE;
		if (u32_oct((uintmax_t)MAJOR(arcn->sb.st_rdev), hd->devmajor,
		   sizeof(hd->devmajor), 3) ||
		   u32_oct((uintmax_t)MINOR(arcn->sb.st_rdev), hd->devminor,
		   sizeof(hd->devminor), 3) ||
		   u32_oct((uintmax_t)0L, hd->size, sizeof(hd->size), 3))
			return size_err("DEVTYPE", arcn);
		break;
	case PAX_FIF:
		hd->typeflag = FIFOTYPE;
		if (u32_oct((uintmax_t)0L, hd->size, sizeof(hd->size), 3))
			return size_err("FIFOTYPE", arcn);
		break;
	case PAX_GLL:
	case PAX_SLK:
	case PAX_HLK:
	case PAX_HRG:
		if (arcn->type == PAX_SLK)
			hd->typeflag = SYMTYPE;
		else if (arcn->type == PAX_GLL)
			hd->typeflag = LONGLINKTYPE;
		else
			hd->typeflag = LNKTYPE;
		strlcpy(hd->linkname, arcn->ln_name, sizeof(hd->linkname));
		if (u32_oct((uintmax_t)gnu_hack_len, hd->size,
		    sizeof(hd->size), 3))
			return size_err("LINKTYPE", arcn);
		break;
	case PAX_GLF:
	case PAX_REG:
	case PAX_CTG:
	default:
		/*
		 * file data with this type, set the padding
		 */
		if (arcn->type == PAX_GLF) {
			hd->typeflag = LONGNAMETYPE;
			arcn->pad = TAR_PAD(gnu_hack_len);
			if (OFFT_OCT((uint32_t)gnu_hack_len, hd->size,
			    sizeof(hd->size), 3)) {
				tty_warn(1,"File is too long for ustar %s",
				    arcn->org_name);
				return 1;
			}
		} else {
			if (arcn->type == PAX_CTG)
				hd->typeflag = CONTTYPE;
			else
				hd->typeflag = REGTYPE;
			arcn->pad = TAR_PAD(arcn->sb.st_size);
			if (OFFT_OCT(arcn->sb.st_size, hd->size,
			    sizeof(hd->size), 3)) {
				tty_warn(1,"File is too long for ustar %s",
				    arcn->org_name);
				return 1;
			}
		}
		break;
	}

	strncpy(hd->magic, TMAGIC, TMAGLEN);
	if (is_gnutar)
		hd->magic[TMAGLEN - 1] = hd->version[0] = ' ';
	else
		strncpy(hd->version, TVERSION, TVERSLEN);

	/*
	 * set the remaining fields. Some versions want all 16 bits of mode
	 * we better humor them (they really do not meet spec though)....
	 */
	if (u32_oct((uintmax_t)arcn->sb.st_mode, hd->mode, sizeof(hd->mode), 3))
		return size_err("MODE", arcn);
	if (u32_oct((uintmax_t)arcn->sb.st_uid, hd->uid, sizeof(hd->uid), 3))
		return size_err("UID", arcn);
	if (u32_oct((uintmax_t)arcn->sb.st_gid, hd->gid, sizeof(hd->gid), 3))
		return size_err("GID", arcn);
	mtime = tst.st_ino ? tst.st_mtime : arcn->sb.st_mtime;
	if (u32_oct(mtime, hd->mtime, sizeof(hd->mtime), 3))
		return size_err("MTIME", arcn);
	user = user_from_uid(arcn->sb.st_uid, 1);
	group = group_from_gid(arcn->sb.st_gid, 1);
	strncpy(hd->uname, user ? user : "", sizeof(hd->uname));
	strncpy(hd->gname, group ? group : "", sizeof(hd->gname));

	/*
	 * calculate and store the checksum write the header to the archive
	 * return 0 tells the caller to now write the file data, 1 says no data
	 * needs to be written
	 */
	if (u32_oct(tar_chksm(hdblk, sizeof(HD_USTAR)), hd->chksum,
	   sizeof(hd->chksum), 3))
		return size_err("CHKSUM", arcn);
	if (wr_rdbuf(hdblk, sizeof(HD_USTAR)) < 0)
		return -1;
	if (wr_skip((off_t)(BLKMULT - sizeof(HD_USTAR))) < 0)
		return -1;
	if (gnu_hack_string) {
		int res = wr_rdbuf(gnu_hack_string, gnu_hack_len);
		int pad = gnu_hack_len;
		gnu_hack_string = NULL;
		gnu_hack_len = 0;
		if (res < 0)
			return -1;
		if (wr_skip((off_t)(BLKMULT - (pad % BLKMULT))) < 0)
			return -1;
	}
	if ((arcn->type == PAX_CTG) || (arcn->type == PAX_REG))
		return 0;
	return 1;
}

/*
 * name_split()
 *	see if the name has to be split for storage in a ustar header. We try
 *	to fit the entire name in the name field without splitting if we can.
 *	The split point is always at a /
 * Return
 *	character pointer to split point (always the / that is to be removed
 *	if the split is not needed, the points is set to the start of the file
 *	name (it would violate the spec to split there). A NULL is returned if
 *	the file name is too long
 */

static char *
name_split(char *name, int len)
{
	char *start;

	/*
	 * check to see if the file name is small enough to fit in the name
	 * field. if so just return a pointer to the name.
	 */
	if (len < TNMSZ)
		return name;
	/*
	 * GNU tar does not honor the prefix+name mode if the magic
	 * is not "ustar\0". So in GNU tar compatibility mode, we don't
	 * split the filename into prefix+name because we are setting
	 * the magic to "ustar " as GNU tar does. This of course will
	 * end up creating a LongLink record in cases where it does not
	 * really need do, but we are behaving like GNU tar after all.
	 */
	if (is_gnutar || len > (TPFSZ + TNMSZ))
		return NULL;

	/*
	 * we start looking at the biggest sized piece that fits in the name
	 * field. We walk forward looking for a slash to split at. The idea is
	 * to find the biggest piece to fit in the name field (or the smallest
	 * prefix we can find) (the -1 is correct the biggest piece would
	 * include the slash between the two parts that gets thrown away)
	 */
	start = name + len - TNMSZ;
	while ((*start != '\0') && (*start != '/'))
		++start;

	/*
	 * if we hit the end of the string, this name cannot be split, so we
	 * cannot store this file.
	 */
	if (*start == '\0')
		return NULL;
	len = start - name;

	/*
	 * NOTE: /str where the length of str == TNMSZ cannot be stored under
	 * the p1003.1-1990 spec for ustar. We could force a prefix of / and
	 * the file would then expand on extract to //str. The len == 0 below
	 * makes this special case follow the spec to the letter.
	 */
	if ((len >= TPFSZ) || (len == 0))
		return NULL;

	/*
	 * ok have a split point, return it to the caller
	 */
	return start;
}

/*
 * convert a glob into a RE, and add it to the list.  we convert to
 * four different RE's (because we're using BRE's and can't use |
 * alternation :-() with this padding:
 *	.*\/ and $
 *	.*\/ and \/.*
 *	^ and $
 *	^ and \/.*
 */
static int
tar_gnutar_exclude_one(const char *line, size_t len)
{
	/* 2 * buffer len + nul */
	char sbuf[MAXPATHLEN * 2 + 1];
	/* + / + // + .*""/\/ + \/.* */
	char rabuf[MAXPATHLEN * 2 + 1 + 1 + 2 + 4 + 4];
	size_t i;
	int j = 0;

	if (line[len - 1] == '\n')
		len--;
	for (i = 0; i < len; i++) {
		/*
		 * convert glob to regexp, escaping everything
		 */
		if (line[i] == '*')
			sbuf[j++] = '.';
		else if (line[i] == '?') {
			sbuf[j++] = '.';
			continue;
		} else if (!isalnum((unsigned char)line[i]) &&
		    !isblank((unsigned char)line[i]))
			sbuf[j++] = '\\';
		sbuf[j++] = line[i];
	}
	sbuf[j] = '\0';
	/* don't need the .*\/ ones if we start with /, i guess */
	if (line[0] != '/') {
		(void)snprintf(rabuf, sizeof rabuf, "/.*\\/%s$//", sbuf);
		if (rep_add(rabuf) < 0)
			return (-1);
		(void)snprintf(rabuf, sizeof rabuf, "/.*\\/%s\\/.*//", sbuf);
		if (rep_add(rabuf) < 0)
			return (-1);
	}

	(void)snprintf(rabuf, sizeof rabuf, "/^%s$//", sbuf);
	if (rep_add(rabuf) < 0)
		return (-1);
	(void)snprintf(rabuf, sizeof rabuf, "/^%s\\/.*//", sbuf);
	if (rep_add(rabuf) < 0)
		return (-1);

	return (0);
}

/*
 * deal with GNU tar -X/--exclude-from & --exclude switches.  basically,
 * we go through each line of the file, building a string from the "glob"
 * lines in the file into RE lines, of the form `/^RE$//', which we pass
 * to rep_add(), which will add a empty replacement (exclusion), for the
 * named files.
 */
int
tar_gnutar_minus_minus_exclude(const char *path)
{
	size_t	len = strlen(path);

	if (len > MAXPATHLEN)
		tty_warn(0, "pathname too long: %s", path);
	
	return (tar_gnutar_exclude_one(path, len));
}

int
tar_gnutar_X_compat(const char *path)
{
	char *line;
	FILE *fp;
	int lineno = 0;
	size_t len;

	if (path[0] == '-' && path[1] == '\0')
		fp = stdin;
	else {
		fp = fopen(path, "r");
		if (fp == NULL) {
			tty_warn(1, "cannot open %s: %s", path,
			    strerror(errno));
			return -1;
		}
	}

	while ((line = fgetln(fp, &len))) {
		lineno++;
		if (len > MAXPATHLEN) {
			tty_warn(0, "pathname too long, line %d of %s",
			    lineno, path);
		}
		if (tar_gnutar_exclude_one(line, len))
			return -1;
	}
	if (fp != stdin)
		fclose(fp);
	return 0;
}