BSD 4.4 Lite bin Sources

1 files changed, 1426 insertions, 0 deletions

diff --git a/bin/pax/tables.c b/bin/pax/tables.c
new file mode 100644
index 0000000..3ac1c41
--- /dev/null
+++ b/bin/pax/tables.c
@@ -0,0 +1,1426 @@
+/*-
+ * 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. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. 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.
+ */
+
+#ifndef lint
+static char sccsid[] = "@(#)tables.c	8.1 (Berkeley) 5/31/93";
+#endif /* not lint */
+
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/stat.h>
+#include <sys/param.h>
+#include <sys/fcntl.h>
+#include <stdio.h>
+#include <ctype.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stdlib.h>
+#include "pax.h"
+#include "tables.h"
+#include "extern.h"
+
+/*
+ * Routines for controlling the contents of all the different databases pax
+ * keeps. Tables are dynamically created only when they are needed. The
+ * goal was speed and the ability to work with HUGE archives. The databases
+ * were kept simple, but do have complex rules for when the contents change.
+ * As of this writing, the posix library functions were more complex than
+ * needed for this application (pax databases have very short lifetimes and
+ * do not survive after pax is finished). Pax is required to handle very
+ * large archives. These database routines carefully combine memory usage and
+ * temporary file storage in ways which will not significantly impact runtime
+ * performance while allowing the largest possible archives to be handled.
+ * Trying to force the fit to the posix databases routines was not considered
+ * time well spent.
+ */
+
+static HRDLNK **ltab = NULL;	/* hard link table for detecting hard links */
+static FTM **ftab = NULL;	/* file time table for updating arch */
+static NAMT **ntab = NULL;	/* interactive rename storage table */
+static DEVT **dtab = NULL;	/* device/inode mapping tables */
+static ATDIR **atab = NULL;	/* file tree directory time reset table */
+static int dirfd = -1;		/* storage for setting created dir time/mode */
+static u_long dircnt;		/* entries in dir time/mode storage */
+static int ffd = -1;		/* tmp file for file time table name storage */
+
+static DEVT *chk_dev __P((dev_t, int));
+
+/*
+ * hard link table routines
+ *
+ * The hard link table tries to detect hard links to files using the device and 
+ * inode values. We do this when writing an archive, so we can tell the format
+ * write routine that this file is a hard link to another file. The format
+ * write routine then can store this file in whatever way it wants (as a hard
+ * link if the format supports that like tar, or ignore this info like cpio).
+ * (Actually a field in the format driver table tells us if the format wants
+ * hard link info. if not, we do not waste time looking for them). We also use
+ * the same table when reading an archive. In that situation, this table is
+ * used by the format read routine to detect hard links from stored dev and
+ * inode numbers (like cpio). This will allow pax to create a link when one
+ * can be detected by the archive format.
+ */
+
+/*
+ * lnk_start
+ *	Creates the hard link table.
+ * Return:
+ *	0 if created, -1 if failure
+ */
+
+#if __STDC__
+int
+lnk_start(void)
+#else
+int
+lnk_start()
+#endif
+{
+	if (ltab != NULL)
+		return(0);
+ 	if ((ltab = (HRDLNK **)calloc(L_TAB_SZ, sizeof(HRDLNK *))) == NULL) {
+                warn(1, "Cannot allocate memory for hard link table");
+                return(-1);
+        }
+	return(0);
+}
+
+/*
+ * chk_lnk()
+ *	Looks up entry in hard link hash table. If found, it copies the name
+ *	of the file it is linked to (we already saw that file) into ln_name.
+ *	lnkcnt is decremented and if goes to 1 the node is deleted from the
+ *	database. (We have seen all the links to this file). If not found,
+ *	we add the file to the database if it has the potential for having
+ *	hard links to other files we may process (it has a link count > 1)
+ * Return:
+ *	if found returns 1; if not found returns 0; -1 on error
+ */
+
+#if __STDC__
+int
+chk_lnk(register ARCHD *arcn)
+#else
+int
+chk_lnk(arcn)
+	register ARCHD *arcn;
+#endif
+{
+	register HRDLNK *pt;
+	register HRDLNK **ppt;
+	register u_int indx;
+
+	if (ltab == NULL)
+		return(-1);
+	/*
+	 * ignore those nodes that cannot have hard links
+	 */
+	if ((arcn->type == PAX_DIR) || (arcn->sb.st_nlink <= 1))
+		return(0);
+
+	/*
+	 * hash inode number and look for this file
+	 */
+	indx = ((unsigned)arcn->sb.st_ino) % L_TAB_SZ;
+	if ((pt = ltab[indx]) != NULL) {
+		/*
+		 * it's hash chain in not empty, walk down looking for it
+		 */
+		ppt = &(ltab[indx]);
+		while (pt != NULL) {
+			if ((pt->ino == arcn->sb.st_ino) &&
+			    (pt->dev == arcn->sb.st_dev))
+				break;
+			ppt = &(pt->fow);
+			pt = pt->fow;
+		}
+
+		if (pt != NULL) {
+			/*
+			 * found a link. set the node type and copy in the
+			 * name of the file it is to link to. we need to
+			 * handle hardlinks to regular files differently than
+			 * other links.
+			 */
+			arcn->ln_nlen = l_strncpy(arcn->ln_name, pt->name,
+				PAXPATHLEN+1);
+			if (arcn->type == PAX_REG)
+				arcn->type = PAX_HRG;
+			else
+				arcn->type = PAX_HLK;
+
+			/*
+			 * if we have found all the links to this file, remove
+			 * it from the database
+			 */
+			if (--pt->nlink <= 1) {
+				*ppt = pt->fow;
+				(void)free((char *)pt->name);
+				(void)free((char *)pt);
+			}
+			return(1);
+		}
+	}
+
+	/*
+	 * we never saw this file before. It has links so we add it to the
+	 * front of this hash chain
+	 */
+	if ((pt = (HRDLNK *)malloc(sizeof(HRDLNK))) != NULL) {
+		if ((pt->name = strdup(arcn->name)) != NULL) {
+			pt->dev = arcn->sb.st_dev;
+			pt->ino = arcn->sb.st_ino;
+			pt->nlink = arcn->sb.st_nlink;
+			pt->fow = ltab[indx];
+			ltab[indx] = pt;
+			return(0);
+		}
+		(void)free((char *)pt);
+	}
+
+	warn(1, "Hard link table out of memory");
+	return(-1);
+}
+
+/*
+ * purg_lnk
+ *	remove reference for a file that we may have added to the data base as
+ *	a potential source for hard links. We ended up not using the file, so
+ *	we do not want to accidently point another file at it later on.
+ */
+
+#if __STDC__
+void
+purg_lnk(register ARCHD *arcn)
+#else
+void
+purg_lnk(arcn)
+	register ARCHD *arcn;
+#endif
+{
+	register HRDLNK *pt;
+	register HRDLNK **ppt;
+	register u_int indx;
+
+	if (ltab == NULL)
+		return;
+	/*
+	 * do not bother to look if it could not be in the database
+	 */
+	if ((arcn->sb.st_nlink <= 1) || (arcn->type == PAX_DIR) ||
+	    (arcn->type == PAX_HLK) || (arcn->type == PAX_HRG))
+		return;
+
+	/*
+	 * find the hash chain for this inode value, if empty return
+	 */
+	indx = ((unsigned)arcn->sb.st_ino) % L_TAB_SZ;
+	if ((pt = ltab[indx]) == NULL)
+		return;
+
+	/*
+	 * walk down the list looking for the inode/dev pair, unlink and
+	 * free if found
+	 */
+	ppt = &(ltab[indx]);
+	while (pt != NULL) {
+		if ((pt->ino == arcn->sb.st_ino) &&
+		    (pt->dev == arcn->sb.st_dev))
+			break;
+		ppt = &(pt->fow);
+		pt = pt->fow;
+	}
+	if (pt == NULL)
+		return;
+
+	/*
+	 * remove and free it
+	 */
+	*ppt = pt->fow;
+	(void)free((char *)pt->name);
+	(void)free((char *)pt);
+}
+
+/*
+ * lnk_end()
+ *	pull apart a existing link table so we can reuse it. We do this between
+ *	read and write phases of append with update. (The format may have
+ *	used the link table, and we need to start with a fresh table for the
+ *	write phase
+ */
+
+#if __STDC__
+void
+lnk_end(void)
+#else
+void
+lnk_end()
+#endif
+{
+	register int i;
+	register HRDLNK *pt;
+	register HRDLNK *ppt;
+
+	if (ltab == NULL)
+		return;
+
+	for (i = 0; i < L_TAB_SZ; ++i) {
+		if (ltab[i] == NULL)
+			continue;
+		pt = ltab[i];
+		ltab[i] = NULL;
+
+		/*
+		 * free up each entry on this chain
+		 */
+		while (pt != NULL) {
+			ppt = pt;
+			pt = ppt->fow;
+			(void)free((char *)ppt->name);
+			(void)free((char *)ppt);
+		}
+	}
+	return;
+}
+
+/*
+ * modification time table routines
+ *
+ * The modification time table keeps track of last modification times for all
+ * files stored in an archive during a write phase when -u is set. We only
+ * add a file to the archive if it is newer than a file with the same name
+ * already stored on the archive (if there is no other file with the same
+ * name on the archive it is added). This applies to writes and appends.
+ * An append with an -u must read the archive and store the modification time
+ * for every file on that archive before starting the write phase. It is clear
+ * that this is one HUGE database. To save memory space, the actual file names
+ * are stored in a scatch file and indexed by an in memory hash table. The
+ * hash table is indexed by hashing the file path. The nodes in the table store
+ * the length of the filename and the lseek offset within the scratch file 
+ * where the actual name is stored. Since there are never any deletions to this
+ * table, fragmentation of the scratch file is never a issue. Lookups seem to
+ * not exhibit any locality at all (files in the database are rarely 
+ * looked up more than once...). So caching is just a waste of memory. The
+ * only limitation is the amount of scatch file space available to store the
+ * path names.
+ */
+
+/*
+ * ftime_start()
+ *	create the file time hash table and open for read/write the scratch
+ *	file. (after created it is unlinked, so when we exit we leave
+ *	no witnesses).
+ * Return:
+ *	0 if the table and file was created ok, -1 otherwise
+ */
+
+#if __STDC__
+int
+ftime_start(void)
+#else
+int
+ftime_start()
+#endif
+{
+	char *pt;
+
+	if (ftab != NULL)
+		return(0);
+ 	if ((ftab = (FTM **)calloc(F_TAB_SZ, sizeof(FTM *))) == NULL) {
+                warn(1, "Cannot allocate memory for file time table");
+                return(-1);
+        }
+
+	/*
+	 * get random name and create temporary scratch file, unlink name
+	 * so it will get removed on exit
+	 */
+	if ((pt = tempnam((char *)NULL, (char *)NULL)) == NULL)
+		return(-1);
+	(void)unlink(pt);
+
+	if ((ffd = open(pt, O_RDWR | O_CREAT,  S_IRWXU)) < 0) {
+		syswarn(1, errno, "Unable to open temporary file: %s", pt);
+		return(-1);
+	}
+
+	(void)unlink(pt);
+	return(0);
+}
+
+/*
+ * chk_ftime()
+ *	looks up entry in file time hash table. If not found, the file is
+ *	added to the hash table and the file named stored in the scratch file.
+ *	If a file with the same name is found, the file times are compared and
+ *	the most recent file time is retained. If the new file was younger (or
+ *	was not in the database) the new file is selected for storage.
+ * Return:
+ *	0 if file should be added to the archive, 1 if it should be skipped,
+ *	-1 on error
+ */
+
+#if __STDC__
+int
+chk_ftime(register ARCHD *arcn)
+#else
+int
+chk_ftime(arcn)
+	register ARCHD *arcn;
+#endif
+{
+	register FTM *pt;
+	register int namelen;
+	register u_int indx;
+	char ckname[PAXPATHLEN+1];
+
+	/*
+	 * no info, go ahead and add to archive
+	 */
+	if (ftab == NULL)
+		return(0);
+
+	/*
+	 * hash the pathname and look up in table
+	 */
+	namelen = arcn->nlen;
+	indx = st_hash(arcn->name, namelen, F_TAB_SZ);
+	if ((pt = ftab[indx]) != NULL) {
+		/*
+		 * the hash chain is not empty, walk down looking for match
+		 * only read up the path names if the lengths match, speeds
+		 * up the search a lot
+		 */
+		while (pt != NULL) {
+			if (pt->namelen == namelen) {
+				/*
+				 * potential match, have to read the name
+				 * from the scratch file.
+				 */
+				if (lseek(ffd,pt->seek,SEEK_SET) != pt->seek) {
+					syswarn(1, errno,
+					    "Failed ftime table seek");
+					return(-1);
+				}
+				if (read(ffd, ckname, namelen) != namelen) {
+					syswarn(1, errno,
+					    "Failed ftime table read");
+					return(-1);
+				}
+
+				/*
+				 * if the names match, we are done
+				 */
+				if (!strncmp(ckname, arcn->name, namelen))
+					break;
+			}
+
+			/*
+			 * try the next entry on the chain
+			 */
+			pt = pt->fow;
+		}
+
+		if (pt != NULL) {
+			/*
+			 * found the file, compare the times, save the newer
+			 */
+			if (arcn->sb.st_mtime > pt->mtime) {
+				/*
+				 * file is newer
+				 */
+				pt->mtime = arcn->sb.st_mtime;
+				return(0);
+			} 
+			/*
+			 * file is older
+			 */
+			return(1);
+		}
+	}
+
+	/*
+	 * not in table, add it
+	 */
+	if ((pt = (FTM *)malloc(sizeof(FTM))) != NULL) {
+		/*
+		 * add the name at the end of the scratch file, saving the
+		 * offset. add the file to the head of the hash chain
+		 */
+		if ((pt->seek = lseek(ffd, (off_t)0, SEEK_END)) >= 0) {
+			if (write(ffd, arcn->name, namelen) == namelen) {
+				pt->mtime = arcn->sb.st_mtime;
+				pt->namelen = namelen;
+				pt->fow = ftab[indx];
+				ftab[indx] = pt;
+				return(0);
+			}
+			syswarn(1, errno, "Failed write to file time table");
+		} else 
+			syswarn(1, errno, "Failed seek on file time table");
+	} else
+		warn(1, "File time table ran out of memory");
+
+	if (pt != NULL)
+		(void)free((char *)pt);
+	return(-1);
+}
+
+/*
+ * Interactive rename table routines
+ *
+ * The interactive rename table keeps track of the new names that the user
+ * assignes to files from tty input. Since this map is unique for each file
+ * we must store it in case there is a reference to the file later in archive
+ * (a link). Otherwise we will be unable to find the file we know was
+ * extracted. The remapping of these files is stored in a memory based hash
+ * table (it is assumed since input must come from /dev/tty, it is unlikely to
+ * be a very large table).
+ */
+
+/*
+ * name_start()
+ *	create the interactive rename table
+ * Return:
+ *	0 if successful, -1 otherwise
+ */
+
+#if __STDC__
+int
+name_start(void)
+#else
+int
+name_start()
+#endif
+{
+	if (ntab != NULL)
+		return(0);
+ 	if ((ntab = (NAMT **)calloc(N_TAB_SZ, sizeof(NAMT *))) == NULL) {
+                warn(1, "Cannot allocate memory for interactive rename table");
+                return(-1);
+        }
+	return(0);
+}
+
+/*
+ * add_name()
+ *	add the new name to old name mapping just created by the user.
+ *	If an old name mapping is found (there may be duplicate names on an
+ *	archive) only the most recent is kept.
+ * Return:
+ *	0 if added, -1 otherwise
+ */
+
+#if __STDC__
+int
+add_name(register char *oname, int onamelen, char *nname)
+#else
+int
+add_name(oname, onamelen, nname)
+	register char *oname;
+	int onamelen;
+	char *nname;
+#endif
+{
+	register NAMT *pt;
+	register u_int indx;
+
+	if (ntab == NULL) {
+		/*
+		 * should never happen
+		 */
+		warn(0, "No interactive rename table, links may fail\n");
+		return(0); 
+	}
+
+	/*
+	 * look to see if we have already mapped this file, if so we
+	 * will update it
+	 */
+	indx = st_hash(oname, onamelen, N_TAB_SZ);
+	if ((pt = ntab[indx]) != NULL) {
+		/*
+		 * look down the has chain for the file
+		 */
+		while ((pt != NULL) && (strcmp(oname, pt->oname) != 0))
+			pt = pt->fow;
+
+		if (pt != NULL) {
+			/*
+			 * found an old mapping, replace it with the new one
+			 * the user just input (if it is different)
+			 */
+			if (strcmp(nname, pt->nname) == 0)
+				return(0);
+
+			(void)free((char *)pt->nname);
+			if ((pt->nname = strdup(nname)) == NULL) {
+				warn(1, "Cannot update rename table");
+				return(-1);
+			}
+			return(0);
+		}
+	}
+
+	/*
+	 * this is a new mapping, add it to the table
+	 */
+	if ((pt = (NAMT *)malloc(sizeof(NAMT))) != NULL) {
+		if ((pt->oname = strdup(oname)) != NULL) {
+			if ((pt->nname = strdup(nname)) != NULL) {
+				pt->fow = ntab[indx];
+				ntab[indx] = pt;
+				return(0);
+			}
+			(void)free((char *)pt->oname);
+		}
+		(void)free((char *)pt);
+	}
+	warn(1, "Interactive rename table out of memory");
+	return(-1);
+}
+
+/*
+ * sub_name()
+ *	look up a link name to see if it points at a file that has been
+ *	remapped by the user. If found, the link is adjusted to contain the
+ *	new name (oname is the link to name)
+ */
+
+#if __STDC__
+void
+sub_name(register char *oname, int *onamelen)
+#else
+void
+sub_name(oname, onamelen)
+	register char *oname;
+	int *onamelen;
+#endif
+{
+	register NAMT *pt;
+	register u_int indx;
+
+	if (ntab == NULL)
+		return;
+	/*
+	 * look the name up in the hash table
+	 */
+	indx = st_hash(oname, *onamelen, N_TAB_SZ);
+	if ((pt = ntab[indx]) == NULL)
+		return;
+
+	while (pt != NULL) {
+		/*
+		 * walk down the hash cahin looking for a match
+		 */
+		if (strcmp(oname, pt->oname) == 0) {
+			/*
+			 * found it, replace it with the new name
+			 * and return (we know that oname has enough space)
+			 */
+			*onamelen = l_strncpy(oname, pt->nname, PAXPATHLEN+1);
+			return;
+		}
+		pt = pt->fow;
+	}
+
+	/*
+	 * no match, just return
+	 */
+	return;
+}
+    
+/*
+ * device/inode mapping table routines
+ * (used with formats that store device and inodes fields)
+ *
+ * device/inode mapping tables remap the device field in a archive header. The
+ * device/inode fields are used to determine when files are hard links to each
+ * other. However these values have very little meaning outside of that. This
+ * database is used to solve one of two different problems.
+ *
+ * 1) when files are appended to an archive, while the new files may have hard
+ * links to each other, you cannot determine if they have hard links to any
+ * file already stored on the archive from a prior run of pax. We must assume
+ * that these inode/device pairs are unique only within a SINGLE run of pax
+ * (which adds a set of files to an archive). So we have to make sure the
+ * inode/dev pairs we add each time are always unique. We do this by observing
+ * while the inode field is very dense, the use of the dev field is fairly
+ * sparse. Within each run of pax, we remap any device number of a new archive
+ * member that has a device number used in a prior run and already stored in a
+ * file on the archive. During the read phase of the append, we store the
+ * device numbers used and mark them to not be used by any file during the
+ * write phase. If during write we go to use one of those old device numbers,
+ * we remap it to a new value.
+ *
+ * 2) Often the fields in the archive header used to store these values are
+ * too small to store the entire value. The result is an inode or device value
+ * which can be truncated. This really can foul up an archive. With truncation
+ * we end up creating links between files that are really not links (after
+ * truncation the inodes are the same value). We address that by detecting
+ * truncation and forcing a remap of the device field to split truncated
+ * inodes away from each other. Each truncation creates a pattern of bits that
+ * are removed. We use this pattern of truncated bits to partition the inodes
+ * on a single device to many different devices (each one represented by the
+ * truncated bit pattern). All inodes on the same device that have the same
+ * truncation pattern are mapped to the same new device. Two inodes that
+ * truncate to the same value clearly will always have different truncation
+ * bit patterns, so they will be split from away each other. When we spot
+ * device truncation we remap the device number to a non truncated value.
+ * (for more info see table.h for the data structures involved).
+ */
+
+/*
+ * dev_start()
+ *	create the device mapping table
+ * Return:
+ *	0 if successful, -1 otherwise
+ */
+
+#if __STDC__
+int
+dev_start(void)
+#else
+int
+dev_start()
+#endif
+{
+	if (dtab != NULL)
+		return(0);
+ 	if ((dtab = (DEVT **)calloc(D_TAB_SZ, sizeof(DEVT *))) == NULL) {
+                warn(1, "Cannot allocate memory for device mapping table");
+                return(-1);
+        }
+	return(0);
+}
+
+/*
+ * add_dev()
+ *	add a device number to the table. this will force the device to be
+ *	remapped to a new value if it be used during a write phase. This
+ *	function is called during the read phase of an append to prohibit the
+ *	use of any device number already in the archive.
+ * Return:
+ *	0 if added ok, -1 otherwise
+ */
+
+#if __STDC__
+int
+add_dev(register ARCHD *arcn)
+#else
+int
+add_dev(arcn)
+	register ARCHD *arcn;
+#endif
+{
+	if (chk_dev(arcn->sb.st_dev, 1) == NULL)
+		return(-1);
+	return(0);
+}
+
+/*
+ * chk_dev()
+ *	check for a device value in the device table. If not found and the add
+ *	flag is set, it is added. This does NOT assign any mapping values, just
+ *	adds the device number as one that need to be remapped. If this device
+ *	is alread mapped, just return with a pointer to that entry.
+ * Return:
+ *	pointer to the entry for this device in the device map table. Null
+ *	if the add flag is not set and the device is not in the table (it is
+ *	not been seen yet). If add is set and the device cannot be added, null
+ *	is returned (indicates an error).
+ */
+
+#if __STDC__
+static DEVT *
+chk_dev(dev_t dev, int add)
+#else
+static DEVT *
+chk_dev(dev, add)
+	dev_t dev;
+	int add;
+#endif
+{
+	register DEVT *pt;
+	register u_int indx;
+
+	if (dtab == NULL)
+		return(NULL);
+	/*
+	 * look to see if this device is already in the table
+	 */
+	indx = ((unsigned)dev) % D_TAB_SZ;
+	if ((pt = dtab[indx]) != NULL) {
+		while ((pt != NULL) && (pt->dev != dev))
+			pt = pt->fow;
+
+		/*
+		 * found it, return a pointer to it
+		 */
+		if (pt != NULL)
+			return(pt);
+	}
+
+	/*
+	 * not in table, we add it only if told to as this may just be a check
+	 * to see if a device number is being used.
+	 */
+	if (add == 0)
+		return(NULL);
+
+	/*
+	 * allocate a node for this device and add it to the front of the hash
+	 * chain. Note we do not assign remaps values here, so the pt->list
+	 * list must be NULL.
+	 */
+	if ((pt = (DEVT *)malloc(sizeof(DEVT))) == NULL) {
+		warn(1, "Device map table out of memory");
+		return(NULL);
+	}
+	pt->dev = dev;
+	pt->list = NULL;
+	pt->fow = dtab[indx];
+	dtab[indx] = pt;
+	return(pt);
+}
+/*
+ * map_dev()
+ *	given an inode and device storage mask (the mask has a 1 for each bit
+ *	the archive format is able to store in a header), we check for inode
+ *	and device truncation and remap the device as required. Device mapping
+ *	can also occur when during the read phase of append a device number was
+ *	seen (and was marked as do not use during the write phase). WE ASSUME
+ *	that unsigned longs are the same size or bigger than the fields used
+ *	for ino_t and dev_t. If not the types will have to be changed.
+ * Return:
+ *	0 if all ok, -1 otherwise.
+ */
+
+#if __STDC__
+int
+map_dev(register ARCHD *arcn, u_long dev_mask, u_long ino_mask)
+#else
+int
+map_dev(arcn, dev_mask, ino_mask)
+	register ARCHD *arcn;
+	u_long dev_mask;
+	u_long ino_mask;
+#endif
+{
+	register DEVT *pt;
+	register DLIST *dpt;
+	static dev_t lastdev = 0;	/* next device number to try */
+	int trc_ino = 0;
+	int trc_dev = 0;
+	ino_t trunc_bits = 0;
+	ino_t nino;
+
+	if (dtab == NULL)
+		return(0);
+	/*
+	 * check for device and inode truncation, and extract the truncated
+	 * bit pattern. 
+	 */
+	if ((arcn->sb.st_dev & (dev_t)dev_mask) != arcn->sb.st_dev)
+		++trc_dev;
+	if ((nino = arcn->sb.st_ino & (ino_t)ino_mask) != arcn->sb.st_ino) {
+		++trc_ino;
+		trunc_bits = arcn->sb.st_ino & (ino_t)(~ino_mask);
+	}
+
+	/*
+	 * see if this device is already being mapped, look up the device
+	 * then find the truncation bit pattern which applies
+	 */
+	if ((pt = chk_dev(arcn->sb.st_dev, 0)) != NULL) {
+		/*
+		 * this device is already marked to be remapped
+		 */
+		for (dpt = pt->list; dpt != NULL; dpt = dpt->fow)
+			if (dpt->trunc_bits == trunc_bits)
+				break;
+
+		if (dpt != NULL) {
+			/*
+			 * we are being remapped for this device and pattern
+			 * change the device number to be stored and return
+			 */
+			arcn->sb.st_dev = dpt->dev;
+			arcn->sb.st_ino = nino;
+			return(0);
+		}
+	} else {
+		/*
+		 * this device is not being remapped YET. if we do not have any
+		 * form of truncation, we do not need a remap
+		 */
+		if (!trc_ino && !trc_dev)
+			return(0);
+
+		/*
+		 * we have truncation, have to add this as a device to remap
+		 */
+		if ((pt = chk_dev(arcn->sb.st_dev, 1)) == NULL)
+			goto bad;
+
+		/*
+		 * if we just have a truncated inode, we have to make sure that
+		 * all future inodes that do not truncate (they have the
+		 * truncation pattern of all 0's) continue to map to the same
+		 * device number. We probably have already written inodes with
+		 * this device number to the archive with the truncation
+		 * pattern of all 0's. So we add the mapping for all 0's to the
+		 * same device number.
+		 */
+		if (!trc_dev && (trunc_bits != 0)) {
+			if ((dpt = (DLIST *)malloc(sizeof(DLIST))) == NULL)
+				goto bad;
+			dpt->trunc_bits = 0;
+			dpt->dev = arcn->sb.st_dev;
+			dpt->fow = pt->list;
+			pt->list = dpt;
+		}
+	}
+
+	/*
+	 * look for a device number not being used. We must watch for wrap
+	 * around on lastdev (so we do not get stuck looking forever!)
+	 */
+	while (++lastdev > 0) {
+		if (chk_dev(lastdev, 0) != NULL)
+			continue;
+		/*
+		 * found an unused value. If we have reached truncation point
+		 * for this format we are hosed, so we give up. Otherwise we
+		 * mark it as being used.
+		 */
+		if (((lastdev & ((dev_t)dev_mask)) != lastdev) ||
+		    (chk_dev(lastdev, 1) == NULL))
+			goto bad;
+		break;
+	}
+
+	if ((lastdev <= 0) || ((dpt = (DLIST *)malloc(sizeof(DLIST))) == NULL))
+		goto bad;
+
+	/*
+	 * got a new device number, store it under this truncation pattern.
+	 * change the device number this file is being stored with.
+	 */
+	dpt->trunc_bits = trunc_bits;
+	dpt->dev = lastdev;
+	dpt->fow = pt->list;
+	pt->list = dpt;
+	arcn->sb.st_dev = lastdev;
+	arcn->sb.st_ino = nino;
+	return(0);
+
+    bad:
+	warn(1, "Unable to fix truncated inode/device field when storing %s",
+	    arcn->name);
+	warn(0, "Archive may create improper hard links when extracted");
+	return(0);
+}
+
+/*
+ * directory access/mod time reset table routines (for directories READ by pax)
+ *
+ * The pax -t flag requires that access times of archive files to be the same
+ * before being read by pax. For regular files, access time is restored after
+ * the file has been copied. This database provides the same functionality for
+ * directories read during file tree traversal. Restoring directory access time
+ * is more complex than files since directories may be read several times until
+ * all the descendants in their subtree are visited by fts. Directory access
+ * and modification times are stored during the fts pre-order visit (done
+ * before any descendants in the subtree is visited) and restored after the
+ * fts post-order visit (after all the descendants have been visited). In the
+ * case of premature exit from a subtree (like from the effects of -n), any
+ * directory entries left in this database are reset during final cleanup
+ * operations of pax. Entries are hashed by inode number for fast lookup.
+ */
+
+/*
+ * atdir_start()
+ *	create the directory access time database for directories READ by pax.
+ * Return:
+ *	0 is created ok, -1 otherwise.
+ */
+
+#if __STDC__
+int
+atdir_start(void)
+#else
+int
+atdir_start()
+#endif
+{
+	if (atab != NULL)
+		return(0);
+ 	if ((atab = (ATDIR **)calloc(A_TAB_SZ, sizeof(ATDIR *))) == NULL) {
+                warn(1,"Cannot allocate space for directory access time table");
+                return(-1);
+        }
+	return(0);
+}
+
+
+/*
+ * atdir_end()
+ *	walk through the directory access time table and reset the access time
+ *	of any directory who still has an entry left in the database. These
+ *	entries are for directories READ by pax
+ */
+
+#if __STDC__
+void
+atdir_end(void)
+#else
+void
+atdir_end()
+#endif
+{
+	register ATDIR *pt;
+	register int i;
+
+	if (atab == NULL)
+		return;
+	/*
+	 * for each non-empty hash table entry reset all the directories
+	 * chained there.
+	 */
+	for (i = 0; i < A_TAB_SZ; ++i) {
+		if ((pt = atab[i]) == NULL)
+			continue;
+		/*
+		 * remember to force the times, set_ftime() looks at pmtime
+		 * and patime, which only applies to things CREATED by pax,
+		 * not read by pax. Read time reset is controlled by -t.
+		 */
+		for (; pt != NULL; pt = pt->fow)
+			set_ftime(pt->name, pt->mtime, pt->atime, 1);
+	}
+}
+
+/*
+ * add_atdir()
+ *	add a directory to the directory access time table. Table is hashed
+ *	and chained by inode number. This is for directories READ by pax
+ */
+
+#if __STDC__
+void
+add_atdir(char *fname, dev_t dev, ino_t ino, time_t mtime, time_t atime)
+#else
+void
+add_atdir(fname, dev, ino, mtime, atime)
+	char *fname;
+	dev_t dev;
+	ino_t ino;
+	time_t mtime;
+	time_t atime;
+#endif
+{
+	register ATDIR *pt;
+	register u_int indx;
+
+	if (atab == NULL)
+		return;
+
+	/*
+	 * make sure this directory is not already in the table, if so just 
+	 * return (the older entry always has the correct time). The only
+	 * way this will happen is when the same subtree can be traversed by
+	 * different args to pax and the -n option is aborting fts out of a
+	 * subtree before all the post-order visits have been made).
+	 */
+	indx = ((unsigned)ino) % A_TAB_SZ;
+	if ((pt = atab[indx]) != NULL) {
+		while (pt != NULL) {
+			if ((pt->ino == ino) && (pt->dev == dev))
+				break;
+			pt = pt->fow;
+		}
+
+		/*
+		 * oops, already there. Leave it alone.
+		 */
+		if (pt != NULL)
+			return;
+	}
+
+	/*
+	 * add it to the front of the hash chain
+	 */
+	if ((pt = (ATDIR *)malloc(sizeof(ATDIR))) != NULL) {
+		if ((pt->name = strdup(fname)) != NULL) {
+			pt->dev = dev;
+			pt->ino = ino;
+			pt->mtime = mtime;
+			pt->atime = atime;
+			pt->fow = atab[indx];
+			atab[indx] = pt;
+			return;
+		}
+		(void)free((char *)pt);
+	}
+
+	warn(1, "Directory access time reset table ran out of memory");
+	return;
+}
+
+/*
+ * get_atdir()
+ *	look up a directory by inode and device number to obtain the access
+ *	and modification time you want to set to. If found, the modification
+ *	and access time parameters are set and the entry is removed from the
+ *	table (as it is no longer needed). These are for directories READ by
+ *	pax
+ * Return:
+ *	0 if found, -1 if not found.
+ */
+
+#if __STDC__
+int
+get_atdir(dev_t dev, ino_t ino, time_t *mtime, time_t *atime)
+#else
+int
+get_atdir(dev, ino, mtime, atime)
+	dev_t dev;
+	ino_t ino;
+	time_t *mtime;
+	time_t *atime;
+#endif
+{
+	register ATDIR *pt;
+	register ATDIR **ppt;
+	register u_int indx;
+
+	if (atab == NULL)
+		return(-1);
+	/*
+	 * hash by inode and search the chain for an inode and device match
+	 */
+	indx = ((unsigned)ino) % A_TAB_SZ;
+	if ((pt = atab[indx]) == NULL)
+		return(-1);
+
+	ppt = &(atab[indx]);
+	while (pt != NULL) {
+		if ((pt->ino == ino) && (pt->dev == dev))
+			break;
+		/*
+		 * no match, go to next one
+		 */
+		ppt = &(pt->fow);
+		pt = pt->fow;
+	}
+
+	/*
+	 * return if we did not find it.
+	 */
+	if (pt == NULL)
+		return(-1);
+
+	/*
+	 * found it. return the times and remove the entry from the table.
+	 */
+	*ppt = pt->fow;
+	*mtime = pt->mtime;
+	*atime = pt->atime;
+	(void)free((char *)pt->name);
+	(void)free((char *)pt);
+	return(0);
+}
+
+/*
+ * directory access mode and time storage routines (for directories CREATED
+ * by pax).
+ *
+ * Pax requires that extracted directories, by default, have their access/mod
+ * times and permissions set to the values specified in the archive. During the
+ * actions of extracting (and creating the destination subtree during -rw copy)
+ * directories extracted may be modified after being created. Even worse is
+ * that these directories may have been created with file permissions which
+ * prohibits any descendants of these directories from being extracted. When
+ * directories are created by pax, access rights may be added to permit the
+ * creation of files in their subtree. Every time pax creates a directory, the
+ * times and file permissions specified by the archive are stored. After all
+ * files have been extracted (or copied), these directories have their times
+ * and file modes reset to the stored values. The directory info is restored in
+ * reverse order as entries were added to the data file from root to leaf. To
+ * restore atime properly, we must go backwards. The data file consists of
+ * records with two parts, the file name followed by a DIRDATA trailer. The
+ * fixed sized trailer contains the size of the name plus the off_t location in
+ * the file. To restore we work backwards through the file reading the trailer
+ * then the file name.
+ */
+
+/*
+ * dir_start()
+ *	set up the directory time and file mode storage for directories CREATED
+ *	by pax.
+ * Return:
+ *	0 if ok, -1 otherwise
+ */
+
+#if __STDC__
+int
+dir_start(void)
+#else
+int
+dir_start()
+#endif
+{
+	char *pt;
+
+	if (dirfd != -1)
+		return(0);
+	if ((pt = tempnam((char *)NULL, (char *)NULL)) == NULL)
+		return(-1);
+
+	/*
+	 * unlink the file so it goes away at termination by itself
+	 */
+	(void)unlink(pt);
+	if ((dirfd = open(pt, O_RDWR|O_CREAT, 0600)) >= 0) {
+		(void)unlink(pt);
+		return(0);
+	}
+	warn(1, "Unable to create temporary file for directory times: %s", pt);
+	return(-1);
+}
+
+/*
+ * add_dir()
+ *	add the mode and times for a newly CREATED directory
+ *	name is name of the directory, psb the stat buffer with the data in it,
+ *	frc_mode is a flag that says whether to force the setting of the mode
+ *	(ignoring the user set values for preserving file mode). Frc_mode is
+ *	for the case where we created a file and found that the resulting 
+ *	directory was not writeable and the user asked for file modes to NOT
+ *	be preserved. (we have to preserve what was created by default, so we
+ *	have to force the setting at the end. this is stated explicitly in the
+ *	pax spec)
+ */
+
+#if __STDC__
+void
+add_dir(char *name, int nlen, struct stat *psb, int frc_mode)
+#else
+void
+add_dir(name, nlen, psb, frc_mode)
+	char *name;
+	int nlen;
+	struct stat *psb;
+	int frc_mode;
+#endif
+{
+	DIRDATA dblk;
+
+	if (dirfd < 0)
+		return;
+
+	/*
+	 * get current position (where file name will start) so we can store it
+	 * in the trailer
+	 */
+	if ((dblk.npos = lseek(dirfd, 0L, SEEK_CUR)) < 0) {
+		warn(1,"Unable to store mode and times for directory: %s",name);
+		return;
+	}
+
+	/*
+	 * write the file name followed by the trailer
+	 */
+	dblk.nlen = nlen + 1;
+	dblk.mode = psb->st_mode & 0xffff;
+	dblk.mtime = psb->st_mtime;
+	dblk.atime = psb->st_atime;
+	dblk.frc_mode = frc_mode;
+	if ((write(dirfd, name, dblk.nlen) == dblk.nlen) &&
+	    (write(dirfd, (char *)&dblk, sizeof(dblk)) == sizeof(dblk))) {
+		++dircnt;
+		return;
+	}
+
+	warn(1,"Unable to store mode and times for created directory: %s",name);
+	return;
+}
+
+/*
+ * proc_dir()
+ *	process all file modes and times stored for directories CREATED
+ *	by pax
+ */
+
+#if __STDC__
+void
+proc_dir(void)
+#else
+void
+proc_dir()
+#endif
+{
+	char name[PAXPATHLEN+1];
+	DIRDATA dblk;
+	u_long cnt;
+
+	if (dirfd < 0)
+		return;
+	/*
+	 * read backwards through the file and process each directory
+	 */
+	for (cnt = 0; cnt < dircnt; ++cnt) {
+		/*
+		 * read the trailer, then the file name, if this fails
+		 * just give up.
+		 */
+		if (lseek(dirfd, -((off_t)sizeof(dblk)), SEEK_CUR) < 0) 
+			break;
+		if (read(dirfd,(char *)&dblk, sizeof(dblk)) != sizeof(dblk))
+			break;
+		if (lseek(dirfd, dblk.npos, SEEK_SET) < 0) 
+			break;
+		if (read(dirfd, name, dblk.nlen) != dblk.nlen)
+			break;
+		if (lseek(dirfd, dblk.npos, SEEK_SET) < 0) 
+			break;
+
+		/*
+		 * frc_mode set, make sure we set the file modes even if
+		 * the user didn't ask for it (see file_subs.c for more info)
+		 */
+		if (pmode || dblk.frc_mode)
+			set_pmode(name, dblk.mode);
+		if (patime || pmtime)
+			set_ftime(name, dblk.mtime, dblk.atime, 0);
+	}
+
+	(void)close(dirfd);
+	dirfd = -1;
+	if (cnt != dircnt)
+		warn(1,"Unable to set mode and times for created directories");
+	return;
+}
+
+/*
+ * database independent routines
+ */
+
+/*
+ * st_hash()
+ *	hashes filenames to a u_int for hashing into a table. Looks at the tail
+ *	end of file, as this provides far better distribution than any other
+ *	part of the name. For performance reasons we only care about the last
+ *	MAXKEYLEN chars (should be at LEAST large enough to pick off the file
+ *	name). Was tested on 500,000 name file tree traversal from the root
+ *	and gave almost a perfectly uniform distribution of keys when used with
+ *	prime sized tables (MAXKEYLEN was 128 in test). Hashes (sizeof int)
+ *	chars at a time and pads with 0 for last addition.
+ * Return:
+ *	the hash value of the string MOD (%) the table size.
+ */
+
+#if __STDC__
+u_int
+st_hash(char *name, int len, int tabsz)
+#else
+u_int
+st_hash(name, len, tabsz)
+	char *name;
+	int len;
+	int tabsz;
+#endif
+{
+	register char *pt;
+	register char *dest;
+	register char *end;
+	register int i;
+	register u_int key = 0;
+	register int steps;
+	register int res;
+	u_int val;
+
+	/*
+	 * only look at the tail up to MAXKEYLEN, we do not need to waste
+	 * time here (remember these are pathnames, the tail is what will
+	 * spread out the keys)
+	 */
+	if (len > MAXKEYLEN) {
+                pt = &(name[len - MAXKEYLEN]);
+		len = MAXKEYLEN;
+	} else
+		pt = name;
+
+	/*
+	 * calculate the number of u_int size steps in the string and if
+	 * there is a runt to deal with
+	 */
+	steps = len/sizeof(u_int);
+	res = len % sizeof(u_int);
+
+	/*
+	 * add up the value of the string in unsigned integer sized pieces
+	 * too bad we cannot have unsigned int aligned strings, then we
+	 * could avoid the expensive copy.
+	 */
+	for (i = 0; i < steps; ++i) {
+		end = pt + sizeof(u_int);
+		dest = (char *)&val;
+		while (pt < end)
+			*dest++ = *pt++;
+		key += val;
+	}
+
+	/*
+	 * add in the runt padded with zero to the right
+	 */
+	if (res) {
+		val = 0;
+		end = pt + res;
+		dest = (char *)&val;
+		while (pt < end)
+			*dest++ = *pt++;
+		key += val;
+	}
+
+	/*
+	 * return the result mod the table size
+	 */
+	return(key % tabsz);
+}