add tools

1 files changed, 1106 insertions, 0 deletions

diff --git a/bin/pax/file_subs.c b/bin/pax/file_subs.c
new file mode 100644
index 0000000..2c0994f
--- /dev/null
+++ b/bin/pax/file_subs.c
@@ -0,0 +1,1106 @@
+/*	$OpenBSD: file_subs.c,v 1.55 2020/03/23 20:04:19 espie Exp $	*/
+/*	$NetBSD: file_subs.c,v 1.4 1995/03/21 09:07:18 cgd 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.
+ */
+
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include "pax.h"
+#include "extern.h"
+
+static int
+mk_link(char *, struct stat *, char *, int);
+
+/*
+ * routines that deal with file operations such as: creating, removing;
+ * and setting access modes, uid/gid and times of files
+ */
+
+/*
+ * file_creat()
+ *	Create and open a file.
+ * Return:
+ *	file descriptor or -1 for failure
+ */
+
+int
+file_creat(ARCHD *arcn)
+{
+	int fd = -1;
+	mode_t file_mode;
+	int oerrno;
+
+	/*
+	 * Assume file doesn't exist, so just try to create it, most times this
+	 * works. We have to take special handling when the file does exist. To
+	 * detect this, we use O_EXCL. For example when trying to create a
+	 * file and a character device or fifo exists with the same name, we
+	 * can accidently open the device by mistake (or block waiting to open).
+	 * If we find that the open has failed, then spend the effort to
+	 * figure out why. This strategy was found to have better average
+	 * performance in common use than checking the file (and the path)
+	 * first with lstat.
+	 */
+	file_mode = arcn->sb.st_mode & FILEBITS;
+	if ((fd = open(arcn->name, O_WRONLY | O_CREAT | O_EXCL,
+	    file_mode)) >= 0)
+		return(fd);
+
+	/*
+	 * the file seems to exist. First we try to get rid of it (found to be
+	 * the second most common failure when traced). If this fails, only
+	 * then we go to the expense to check and create the path to the file
+	 */
+	if (unlnk_exist(arcn->name, arcn->type) != 0)
+		return(-1);
+
+	for (;;) {
+		/*
+		 * try to open it again, if this fails, check all the nodes in
+		 * the path and give it a final try. if chk_path() finds that
+		 * it cannot fix anything, we will skip the last attempt
+		 */
+		if ((fd = open(arcn->name, O_WRONLY | O_CREAT | O_TRUNC,
+		    file_mode)) >= 0)
+			break;
+		oerrno = errno;
+		if (nodirs || chk_path(arcn->name,arcn->sb.st_uid,arcn->sb.st_gid, 0) < 0) {
+			syswarn(1, oerrno, "Unable to create %s", arcn->name);
+			return(-1);
+		}
+	}
+	return(fd);
+}
+
+/*
+ * file_close()
+ *	Close file descriptor to a file just created by pax. Sets modes,
+ *	ownership and times as required.
+ * Return:
+ *	0 for success, -1 for failure
+ */
+
+void
+file_close(ARCHD *arcn, int fd)
+{
+	int res = 0;
+
+	if (fd < 0)
+		return;
+
+	/*
+	 * set owner/groups first as this may strip off mode bits we want
+	 * then set file permission modes. Then set file access and
+	 * modification times.
+	 */
+	if (pids)
+		res = fset_ids(arcn->name, fd, arcn->sb.st_uid,
+		    arcn->sb.st_gid);
+
+	/*
+	 * IMPORTANT SECURITY NOTE:
+	 * if not preserving mode or we cannot set uid/gid, then PROHIBIT
+	 * set uid/gid bits
+	 */
+	if (!pmode || res)
+		arcn->sb.st_mode &= ~(SETBITS);
+	if (pmode)
+		fset_pmode(arcn->name, fd, arcn->sb.st_mode);
+	if (patime || pmtime)
+		fset_ftime(arcn->name, fd, &arcn->sb.st_mtim,
+		    &arcn->sb.st_atim, 0);
+	if (close(fd) == -1)
+		syswarn(0, errno, "Unable to close file descriptor on %s",
+		    arcn->name);
+}
+
+/*
+ * lnk_creat()
+ *	Create a hard link to arcn->ln_name from arcn->name. arcn->ln_name
+ *	must exist;
+ * Return:
+ *	0 if ok, -1 otherwise
+ */
+
+int
+lnk_creat(ARCHD *arcn)
+{
+	struct stat sb;
+	int res;
+
+	/*
+	 * we may be running as root, so we have to be sure that link target
+	 * is not a directory, so we lstat and check
+	 */
+	if (lstat(arcn->ln_name, &sb) == -1) {
+		syswarn(1,errno,"Unable to link to %s from %s", arcn->ln_name,
+		    arcn->name);
+		return(-1);
+	}
+
+	if (S_ISDIR(sb.st_mode)) {
+		paxwarn(1, "A hard link to the directory %s is not allowed",
+		    arcn->ln_name);
+		return(-1);
+	}
+
+	res = mk_link(arcn->ln_name, &sb, arcn->name, 0);
+	if (res == 0) {
+		/* check for a hardlink to a placeholder symlink */
+		res = sltab_add_link(arcn->name, &sb);
+
+		if (res < 0) {
+			/* arrgh, it failed, clean up */
+			unlink(arcn->name);
+		}
+	}
+
+	return (res);
+}
+
+/*
+ * cross_lnk()
+ *	Create a hard link to arcn->org_name from arcn->name. Only used in copy
+ *	with the -l flag. No warning or error if this does not succeed (we will
+ *	then just create the file)
+ * Return:
+ *	1 if copy() should try to create this file node
+ *	0 if cross_lnk() ok, -1 for fatal flaw (like linking to self).
+ */
+
+int
+cross_lnk(ARCHD *arcn)
+{
+	/*
+	 * try to make a link to original file (-l flag in copy mode). make
+	 * sure we do not try to link to directories in case we are running as
+	 * root (and it might succeed).
+	 */
+	if (arcn->type == PAX_DIR)
+		return(1);
+	return(mk_link(arcn->org_name, &(arcn->sb), arcn->name, 1));
+}
+
+/*
+ * chk_same()
+ *	In copy mode if we are not trying to make hard links between the src
+ *	and destinations, make sure we are not going to overwrite ourselves by
+ *	accident. This slows things down a little, but we have to protect all
+ *	those people who make typing errors.
+ * Return:
+ *	1 the target does not exist, go ahead and copy
+ *	0 skip it file exists (-k) or may be the same as source file
+ */
+
+int
+chk_same(ARCHD *arcn)
+{
+	struct stat sb;
+
+	/*
+	 * if file does not exist, return. if file exists and -k, skip it
+	 * quietly
+	 */
+	if (lstat(arcn->name, &sb) == -1)
+		return(1);
+	if (kflag)
+		return(0);
+
+	/*
+	 * better make sure the user does not have src == dest by mistake
+	 */
+	if ((arcn->sb.st_dev == sb.st_dev) && (arcn->sb.st_ino == sb.st_ino)) {
+		paxwarn(1, "Unable to copy %s, file would overwrite itself",
+		    arcn->name);
+		return(0);
+	}
+	return(1);
+}
+
+/*
+ * mk_link()
+ *	try to make a hard link between two files. if ign set, we do not
+ *	complain.
+ * Return:
+ *	0 if successful (or we are done with this file but no error, such as
+ *	finding the from file exists and the user has set -k).
+ *	1 when ign was set to indicates we could not make the link but we
+ *	should try to copy/extract the file as that might work (and is an
+ *	allowed option). -1 an error occurred.
+ */
+
+static int
+mk_link(char *to, struct stat *to_sb, char *from, int ign)
+{
+	struct stat sb;
+	int oerrno;
+
+	/*
+	 * if from file exists, it has to be unlinked to make the link. If the
+	 * file exists and -k is set, skip it quietly
+	 */
+	if (lstat(from, &sb) == 0) {
+		if (kflag)
+			return(0);
+
+		/*
+		 * make sure it is not the same file, protect the user
+		 */
+		if ((to_sb->st_dev==sb.st_dev)&&(to_sb->st_ino == sb.st_ino)) {
+			paxwarn(1, "Unable to link file %s to itself", to);
+			return(-1);
+		}
+
+		/*
+		 * try to get rid of the file, based on the type
+		 */
+		if (S_ISDIR(sb.st_mode)) {
+			if (rmdir(from) == -1) {
+				syswarn(1, errno, "Unable to remove %s", from);
+				return(-1);
+			}
+			delete_dir(sb.st_dev, sb.st_ino);
+		} else if (unlink(from) == -1) {
+			if (!ign) {
+				syswarn(1, errno, "Unable to remove %s", from);
+				return(-1);
+			}
+			return(1);
+		}
+	}
+
+	/*
+	 * from file is gone (or did not exist), try to make the hard link.
+	 * if it fails, check the path and try it again (if chk_path() says to
+	 * try again)
+	 */
+	for (;;) {
+		if (linkat(AT_FDCWD, to, AT_FDCWD, from, 0) == 0)
+			break;
+		oerrno = errno;
+		if (!nodirs && chk_path(from, to_sb->st_uid, to_sb->st_gid, ign) == 0)
+			continue;
+		if (!ign) {
+			syswarn(1, oerrno, "Could not link to %s from %s", to,
+			    from);
+			return(-1);
+		}
+		return(1);
+	}
+
+	/*
+	 * all right the link was made
+	 */
+	return(0);
+}
+
+/*
+ * node_creat()
+ *	create an entry in the file system (other than a file or hard link).
+ *	If successful, sets uid/gid modes and times as required.
+ * Return:
+ *	0 if ok, -1 otherwise
+ */
+
+int
+node_creat(ARCHD *arcn)
+{
+	int res;
+	int ign = 0;
+	int oerrno;
+	int pass = 0;
+	mode_t file_mode;
+	struct stat sb;
+	char target[PATH_MAX];
+	char *nm = arcn->name;
+	int len, defer_pmode = 0;
+
+	/*
+	 * create node based on type, if that fails try to unlink the node and
+	 * try again. finally check the path and try again. As noted in the
+	 * file and link creation routines, this method seems to exhibit the
+	 * best performance in general use workloads.
+	 */
+	file_mode = arcn->sb.st_mode & FILEBITS;
+
+	for (;;) {
+		switch (arcn->type) {
+		case PAX_DIR:
+			/*
+			 * If -h (or -L) was given in tar-mode, follow the
+			 * potential symlink chain before trying to create the
+			 * directory.
+			 */
+			if (op_mode == OP_TAR && Lflag) {
+				while (lstat(nm, &sb) == 0 &&
+				    S_ISLNK(sb.st_mode)) {
+					len = readlink(nm, target,
+					    sizeof target - 1);
+					if (len == -1) {
+						syswarn(0, errno,
+						   "cannot follow symlink %s in chain for %s",
+						    nm, arcn->name);
+						res = -1;
+						goto badlink;
+					}
+					target[len] = '\0';
+					nm = target;
+				}
+			}
+			res = mkdir(nm, file_mode);
+
+badlink:
+			if (ign)
+				res = 0;
+			break;
+		case PAX_CHR:
+			file_mode |= S_IFCHR;
+			res = mknod(nm, file_mode, arcn->sb.st_rdev);
+			break;
+		case PAX_BLK:
+			file_mode |= S_IFBLK;
+			res = mknod(nm, file_mode, arcn->sb.st_rdev);
+			break;
+		case PAX_FIF:
+			res = mkfifo(nm, file_mode);
+			break;
+		case PAX_SCK:
+			/*
+			 * Skip sockets, operation has no meaning under BSD
+			 */
+			paxwarn(0,
+			    "%s skipped. Sockets cannot be copied or extracted",
+			    nm);
+			return(-1);
+		case PAX_SLK:
+			if (arcn->ln_name[0] != '/' &&
+			    !has_dotdot(arcn->ln_name))
+				res = symlink(arcn->ln_name, nm);
+			else {
+				/*
+				 * absolute symlinks and symlinks with ".."
+				 * have to be deferred to prevent the archive
+				 * from bootstrapping itself to outside the
+				 * working directory.
+				 */
+				res = sltab_add_sym(nm, arcn->ln_name,
+				    arcn->sb.st_mode);
+				if (res == 0)
+					defer_pmode = 1;
+			}
+			break;
+		case PAX_CTG:
+		case PAX_HLK:
+		case PAX_HRG:
+		case PAX_REG:
+		default:
+			/*
+			 * we should never get here
+			 */
+			paxwarn(0, "%s has an unknown file type, skipping",
+				nm);
+			return(-1);
+		}
+
+		/*
+		 * if we were able to create the node break out of the loop,
+		 * otherwise try to unlink the node and try again. if that
+		 * fails check the full path and try a final time.
+		 */
+		if (res == 0)
+			break;
+
+		/*
+		 * we failed to make the node
+		 */
+		oerrno = errno;
+		if ((ign = unlnk_exist(nm, arcn->type)) < 0)
+			return(-1);
+
+		if (++pass <= 1)
+			continue;
+
+		if (nodirs || chk_path(nm,arcn->sb.st_uid,arcn->sb.st_gid, 0) < 0) {
+			syswarn(1, oerrno, "Could not create: %s", nm);
+			return(-1);
+		}
+	}
+
+	/*
+	 * we were able to create the node. set uid/gid, modes and times
+	 */
+	if (pids)
+		res = set_ids(nm, arcn->sb.st_uid, arcn->sb.st_gid);
+	else
+		res = 0;
+
+	/*
+	 * IMPORTANT SECURITY NOTE:
+	 * if not preserving mode or we cannot set uid/gid, then PROHIBIT any
+	 * set uid/gid bits
+	 */
+	if (!pmode || res)
+		arcn->sb.st_mode &= ~(SETBITS);
+	if (pmode && !defer_pmode)
+		set_pmode(nm, arcn->sb.st_mode);
+
+	if (arcn->type == PAX_DIR && op_mode != OP_CPIO) {
+		/*
+		 * Dirs must be processed again at end of extract to set times
+		 * and modes to agree with those stored in the archive. However
+		 * to allow extract to continue, we may have to also set owner
+		 * rights. This allows nodes in the archive that are children
+		 * of this directory to be extracted without failure. Both time
+		 * and modes will be fixed after the entire archive is read and
+		 * before pax exits.  To do that safely, we want the dev+ino
+		 * of the directory we created.
+		 */
+		if (lstat(nm, &sb) == -1) {
+			syswarn(0, errno,"Could not access %s (stat)", nm);
+		} else if (access(nm, R_OK | W_OK | X_OK) == -1) {
+			/*
+			 * We have to add rights to the dir, so we make
+			 * sure to restore the mode. The mode must be
+			 * restored AS CREATED and not as stored if
+			 * pmode is not set.
+			 */
+			set_pmode(nm,
+			    ((sb.st_mode & FILEBITS) | S_IRWXU));
+			if (!pmode)
+				arcn->sb.st_mode = sb.st_mode;
+
+			/*
+			 * we have to force the mode to what was set
+			 * here, since we changed it from the default
+			 * as created.
+			 */
+			arcn->sb.st_dev = sb.st_dev;
+			arcn->sb.st_ino = sb.st_ino;
+			add_dir(nm, &(arcn->sb), 1);
+		} else if (pmode || patime || pmtime) {
+			arcn->sb.st_dev = sb.st_dev;
+			arcn->sb.st_ino = sb.st_ino;
+			add_dir(nm, &(arcn->sb), 0);
+		}
+	} else if (patime || pmtime)
+		set_ftime(nm, &arcn->sb.st_mtim, &arcn->sb.st_atim, 0);
+	return(0);
+}
+
+/*
+ * unlnk_exist()
+ *	Remove node from file system with the specified name. We pass the type
+ *	of the node that is going to replace it. When we try to create a
+ *	directory and find that it already exists, we allow processing to
+ *	continue as proper modes etc will always be set for it later on.
+ * Return:
+ *	0 is ok to proceed, no file with the specified name exists
+ *	-1 we were unable to remove the node, or we should not remove it (-k)
+ *	1 we found a directory and we were going to create a directory.
+ */
+
+int
+unlnk_exist(char *name, int type)
+{
+	struct stat sb;
+
+	/*
+	 * the file does not exist, or -k we are done
+	 */
+	if (lstat(name, &sb) == -1)
+		return(0);
+	if (kflag)
+		return(-1);
+
+	if (S_ISDIR(sb.st_mode)) {
+		/*
+		 * try to remove a directory, if it fails and we were going to
+		 * create a directory anyway, tell the caller (return a 1)
+		 */
+		if (rmdir(name) == -1) {
+			if (type == PAX_DIR)
+				return(1);
+			syswarn(1,errno,"Unable to remove directory %s", name);
+			return(-1);
+		}
+		delete_dir(sb.st_dev, sb.st_ino);
+		return(0);
+	}
+
+	/*
+	 * try to get rid of all non-directory type nodes
+	 */
+	if (unlink(name) == -1) {
+		syswarn(1, errno, "Could not unlink %s", name);
+		return(-1);
+	}
+	return(0);
+}
+
+/*
+ * chk_path()
+ *	We were trying to create some kind of node in the file system and it
+ *	failed. chk_path() makes sure the path up to the node exists and is
+ *	writeable. When we have to create a directory that is missing along the
+ *	path somewhere, the directory we create will be set to the same
+ *	uid/gid as the file has (when uid and gid are being preserved).
+ *	NOTE: this routine is a real performance loss. It is only used as a
+ *	last resort when trying to create entries in the file system.
+ * Return:
+ *	-1 when it could find nothing it is allowed to fix.
+ *	0 otherwise
+ */
+
+int
+chk_path(char *name, uid_t st_uid, gid_t st_gid, int ign)
+{
+	char *spt = name;
+	char *next;
+	struct stat sb;
+	int retval = -1;
+
+	/*
+	 * watch out for paths with nodes stored directly in / (e.g. /bozo)
+	 */
+	while (*spt == '/')
+		++spt;
+
+	for (;;) {
+		/*
+		 * work forward from the first / and check each part of the path
+		 */
+		spt = strchr(spt, '/');
+		if (spt == NULL)
+			break;
+
+		/*
+		 * skip over duplicate slashes; stop if there're only
+		 * trailing slashes left
+		 */
+		next = spt + 1;
+		while (*next == '/')
+			next++;
+		if (*next == '\0')
+			break;
+
+		*spt = '\0';
+
+		/*
+		 * if it exists we assume it is a directory, it is not within
+		 * the spec (at least it seems to read that way) to alter the
+		 * file system for nodes NOT EXPLICITLY stored on the archive.
+		 * If that assumption is changed, you would test the node here
+		 * and figure out how to get rid of it (probably like some
+		 * recursive unlink()) or fix up the directory permissions if
+		 * required (do an access()).
+		 */
+		if (lstat(name, &sb) == 0) {
+			*spt = '/';
+			spt = next;
+			continue;
+		}
+
+		/*
+		 * the path fails at this point, see if we can create the
+		 * needed directory and continue on
+		 */
+		if (mkdir(name, S_IRWXU | S_IRWXG | S_IRWXO) == -1) {
+			if (!ign)
+				syswarn(1, errno, "Unable to mkdir %s", name); 
+			*spt = '/';
+			retval = -1;
+			break;
+		}
+
+		/*
+		 * we were able to create the directory. We will tell the
+		 * caller that we found something to fix, and it is ok to try
+		 * and create the node again.
+		 */
+		retval = 0;
+		if (pids)
+			(void)set_ids(name, st_uid, st_gid);
+
+		/*
+		 * make sure the user doesn't have some strange umask that
+		 * causes this newly created directory to be unusable. We fix
+		 * the modes and restore them back to the creation default at
+		 * the end of pax
+		 */
+		if ((access(name, R_OK | W_OK | X_OK) == -1) &&
+		    (lstat(name, &sb) == 0)) {
+			set_pmode(name, ((sb.st_mode & FILEBITS) | S_IRWXU));
+			add_dir(name, &sb, 1);
+		}
+		*spt = '/';
+		spt = next;
+		continue;
+	}
+	return(retval);
+}
+
+/*
+ * set_ftime()
+ *	Set the access time and modification time for a named file. If frc
+ *	is non-zero we force these times to be set even if the user did not
+ *	request access and/or modification time preservation (this is also
+ *	used by -t to reset access times).
+ *	When ign is zero, only those times the user has asked for are set, the
+ *	other ones are left alone.
+ */
+
+void
+set_ftime(const char *fnm, const struct timespec *mtimp,
+    const struct timespec *atimp, int frc)
+{
+	struct timespec tv[2];
+
+	tv[0] = *atimp;
+	tv[1] = *mtimp;
+
+	if (!frc) {
+		/*
+		 * if we are not forcing, only set those times the user wants
+		 * set.
+		 */
+		if (!patime)
+			tv[0].tv_nsec = UTIME_OMIT;
+		if (!pmtime)
+			tv[1].tv_nsec = UTIME_OMIT;
+	}
+
+	/*
+	 * set the times
+	 */
+	if (utimensat(AT_FDCWD, fnm, tv, AT_SYMLINK_NOFOLLOW) < 0)
+		syswarn(1, errno, "Access/modification time set failed on: %s",
+		    fnm);
+}
+
+void
+fset_ftime(const char *fnm, int fd, const struct timespec *mtimp,
+    const struct timespec *atimp, int frc)
+{
+	struct timespec tv[2];
+
+
+	tv[0] = *atimp;
+	tv[1] = *mtimp;
+
+	if (!frc) {
+		/*
+		 * if we are not forcing, only set those times the user wants
+		 * set.
+		 */
+		if (!patime)
+			tv[0].tv_nsec = UTIME_OMIT;
+		if (!pmtime)
+			tv[1].tv_nsec = UTIME_OMIT;
+	}
+	/*
+	 * set the times
+	 */
+	if (futimens(fd, tv) == -1)
+		syswarn(1, errno, "Access/modification time set failed on: %s",
+		    fnm);
+}
+
+/*
+ * set_ids()
+ *	set the uid and gid of a file system node
+ * Return:
+ *	0 when set, -1 on failure
+ */
+
+int
+set_ids(char *fnm, uid_t uid, gid_t gid)
+{
+	if (fchownat(AT_FDCWD, fnm, uid, gid, AT_SYMLINK_NOFOLLOW) == -1) {
+		/*
+		 * ignore EPERM unless in verbose mode or being run by root.
+		 * if running as pax, POSIX requires a warning.
+		 */
+		if (op_mode == OP_PAX || errno != EPERM || vflag ||
+		    geteuid() == 0)
+			syswarn(1, errno, "Unable to set file uid/gid of %s",
+			    fnm);
+		return(-1);
+	}
+	return(0);
+}
+
+int
+fset_ids(char *fnm, int fd, uid_t uid, gid_t gid)
+{
+	if (fchown(fd, uid, gid) == -1) {
+		/*
+		 * ignore EPERM unless in verbose mode or being run by root.
+		 * if running as pax, POSIX requires a warning.
+		 */
+		if (op_mode == OP_PAX || errno != EPERM || vflag ||
+		    geteuid() == 0)
+			syswarn(1, errno, "Unable to set file uid/gid of %s",
+			    fnm);
+		return(-1);
+	}
+	return(0);
+}
+
+/*
+ * set_pmode()
+ *	Set file access mode
+ */
+
+void
+set_pmode(char *fnm, mode_t mode)
+{
+	mode &= ABITS;
+	if (fchmodat(AT_FDCWD, fnm, mode, AT_SYMLINK_NOFOLLOW) == -1 && errno != EOPNOTSUPP)
+		syswarn(1, errno, "Could not set permissions on %s", fnm);
+}
+
+void
+fset_pmode(char *fnm, int fd, mode_t mode)
+{
+	mode &= ABITS;
+	if (fchmod(fd, mode) == -1)
+		syswarn(1, errno, "Could not set permissions on %s", fnm);
+}
+
+/*
+ * set_attr()
+ *	Given a DIRDATA, restore the mode and times as indicated, but
+ *	only after verifying that it's the directory that we wanted.
+ */
+int
+set_attr(const struct file_times *ft, int force_times, mode_t mode,
+    int do_mode, int in_sig)
+{
+	struct stat sb;
+	int fd, r;
+
+	if (!do_mode && !force_times && !patime && !pmtime)
+		return (0);
+
+	/*
+	 * We could legitimately go through a symlink here,
+	 * so do *not* use O_NOFOLLOW.  The dev+ino check will
+	 * protect us from evil.
+	 */
+	fd = open(ft->ft_name, O_RDONLY | O_DIRECTORY);
+	if (fd == -1) {
+		if (!in_sig)
+			syswarn(1, errno, "Unable to restore mode and times"
+			    " for directory: %s", ft->ft_name);
+		return (-1);
+	}
+
+	if (fstat(fd, &sb) == -1) {
+		if (!in_sig)
+			syswarn(1, errno, "Unable to stat directory: %s",
+			    ft->ft_name);
+		r = -1;
+	} else if (ft->ft_ino != sb.st_ino || ft->ft_dev != sb.st_dev) {
+		if (!in_sig)
+			paxwarn(1, "Directory vanished before restoring"
+			    " mode and times: %s", ft->ft_name);
+		r = -1;
+	} else {
+		/* Whew, it's a match!  Is there anything to change? */
+		if (do_mode && (mode & ABITS) != (sb.st_mode & ABITS))
+			fset_pmode(ft->ft_name, fd, mode);
+		if (((force_times || patime) &&
+		    timespeccmp(&ft->ft_atim, &sb.st_atim, !=)) ||
+		    ((force_times || pmtime) &&
+		    timespeccmp(&ft->ft_mtim, &sb.st_mtim, !=)))
+			fset_ftime(ft->ft_name, fd, &ft->ft_mtim,
+			    &ft->ft_atim, force_times);
+		r = 0;
+	}
+	close(fd);
+
+	return (r);
+}
+
+
+/*
+ * file_write()
+ *	Write/copy a file (during copy or archive extract). This routine knows
+ *	how to copy files with lseek holes in it. (Which are read as file
+ *	blocks containing all 0's but do not have any file blocks associated
+ *	with the data). Typical examples of these are files created by dbm
+ *	variants (.pag files). While the file size of these files are huge, the
+ *	actual storage is quite small (the files are sparse). The problem is
+ *	the holes read as all zeros so are probably stored on the archive that
+ *	way (there is no way to determine if the file block is really a hole,
+ *	we only know that a file block of all zero's can be a hole).
+ *	At this writing, no major archive format knows how to archive files
+ *	with holes. However, on extraction (or during copy, -rw) we have to
+ *	deal with these files. Without detecting the holes, the files can
+ *	consume a lot of file space if just written to disk. This replacement
+ *	for write when passed the basic allocation size of a file system block,
+ *	uses lseek whenever it detects the input data is all 0 within that
+ *	file block. In more detail, the strategy is as follows:
+ *	While the input is all zero keep doing an lseek. Keep track of when we
+ *	pass over file block boundaries. Only write when we hit a non zero
+ *	input. once we have written a file block, we continue to write it to
+ *	the end (we stop looking at the input). When we reach the start of the
+ *	next file block, start checking for zero blocks again. Working on file
+ *	block boundaries significantly reduces the overhead when copying files
+ *	that are NOT very sparse. This overhead (when compared to a write) is
+ *	almost below the measurement resolution on many systems. Without it,
+ *	files with holes cannot be safely copied. It does has a side effect as
+ *	it can put holes into files that did not have them before, but that is
+ *	not a problem since the file contents are unchanged (in fact it saves
+ *	file space). (Except on paging files for diskless clients. But since we
+ *	cannot determine one of those file from here, we ignore them). If this
+ *	ever ends up on a system where CTG files are supported and the holes
+ *	are not desired, just do a conditional test in those routines that
+ *	call file_write() and have it call write() instead. BEFORE CLOSING THE
+ *	FILE, make sure to call file_flush() when the last write finishes with
+ *	an empty block. A lot of file systems will not create an lseek hole at
+ *	the end. In this case we drop a single 0 at the end to force the
+ *	trailing 0's in the file.
+ *	---Parameters---
+ *	rem: how many bytes left in this file system block
+ *	isempt: have we written to the file block yet (is it empty)
+ *	sz: basic file block allocation size
+ *	cnt: number of bytes on this write
+ *	str: buffer to write
+ * Return:
+ *	number of bytes written, -1 on write (or lseek) error.
+ */
+
+int
+file_write(int fd, char *str, int cnt, int *rem, int *isempt, int sz,
+	char *name)
+{
+	char *pt;
+	char *end;
+	int wcnt;
+	char *st = str;
+
+	/*
+	 * while we have data to process
+	 */
+	while (cnt) {
+		if (!*rem) {
+			/*
+			 * We are now at the start of file system block again
+			 * (or what we think one is...). start looking for
+			 * empty blocks again
+			 */
+			*isempt = 1;
+			*rem = sz;
+		}
+
+		/*
+		 * only examine up to the end of the current file block or
+		 * remaining characters to write, whatever is smaller
+		 */
+		wcnt = MINIMUM(cnt, *rem);
+		cnt -= wcnt;
+		*rem -= wcnt;
+		if (*isempt) {
+			/*
+			 * have not written to this block yet, so we keep
+			 * looking for zero's
+			 */
+			pt = st;
+			end = st + wcnt;
+
+			/*
+			 * look for a zero filled buffer
+			 */
+			while ((pt < end) && (*pt == '\0'))
+				++pt;
+
+			if (pt == end) {
+				/*
+				 * skip, buf is empty so far
+				 */
+				if (fd > -1 &&
+				    lseek(fd, wcnt, SEEK_CUR) < 0) {
+					syswarn(1,errno,"File seek on %s",
+					    name);
+					return(-1);
+				}
+				st = pt;
+				continue;
+			}
+			/*
+			 * drat, the buf is not zero filled
+			 */
+			*isempt = 0;
+		}
+
+		/*
+		 * have non-zero data in this file system block, have to write
+		 */
+		if (write(fd, st, wcnt) != wcnt) {
+			syswarn(1, errno, "Failed write to file %s", name);
+			return(-1);
+		}
+		st += wcnt;
+	}
+	return(st - str);
+}
+
+/*
+ * file_flush()
+ *	when the last file block in a file is zero, many file systems will not
+ *	let us create a hole at the end. To get the last block with zeros, we
+ *	write the last BYTE with a zero (back up one byte and write a zero).
+ */
+
+void
+file_flush(int fd, char *fname, int isempt)
+{
+	static char blnk[] = "\0";
+
+	/*
+	 * silly test, but make sure we are only called when the last block is
+	 * filled with all zeros.
+	 */
+	if (!isempt)
+		return;
+
+	/*
+	 * move back one byte and write a zero
+	 */
+	if (lseek(fd, -1, SEEK_CUR) < 0) {
+		syswarn(1, errno, "Failed seek on file %s", fname);
+		return;
+	}
+
+	if (write(fd, blnk, 1) == -1)
+		syswarn(1, errno, "Failed write to file %s", fname);
+}
+
+/*
+ * rdfile_close()
+ *	close a file we have been reading (to copy or archive). If we have to
+ *	reset access time (tflag) do so (the times are stored in arcn).
+ */
+
+void
+rdfile_close(ARCHD *arcn, int *fd)
+{
+	/*
+	 * make sure the file is open
+	 */
+	if (*fd < 0)
+		return;
+
+	/*
+	 * user wants last access time reset
+	 */
+	if (tflag)
+		fset_ftime(arcn->org_name, *fd, &arcn->sb.st_mtim,
+		    &arcn->sb.st_atim, 1);
+
+	(void)close(*fd);
+	*fd = -1;
+}
+
+/*
+ * set_crc()
+ *	read a file to calculate its crc. This is a real drag. Archive formats
+ *	that have this, end up reading the file twice (we have to write the
+ *	header WITH the crc before writing the file contents. Oh well...
+ * Return:
+ *	0 if was able to calculate the crc, -1 otherwise
+ */
+
+int
+set_crc(ARCHD *arcn, int fd)
+{
+	int i;
+	int res;
+	off_t cpcnt = 0;
+	size_t size;
+	u_int32_t crc = 0;
+	char tbuf[FILEBLK];
+	struct stat sb;
+
+	if (fd < 0) {
+		/*
+		 * hmm, no fd, should never happen. well no crc then.
+		 */
+		arcn->crc = 0;
+		return(0);
+	}
+
+	if ((size = arcn->sb.st_blksize) > sizeof(tbuf))
+		size = sizeof(tbuf);
+
+	/*
+	 * read all the bytes we think that there are in the file. If the user
+	 * is trying to archive an active file, forget this file.
+	 */
+	for (;;) {
+		if ((res = read(fd, tbuf, size)) <= 0)
+			break;
+		cpcnt += res;
+		for (i = 0; i < res; ++i)
+			crc += (tbuf[i] & 0xff);
+	}
+
+	/*
+	 * safety check. we want to avoid archiving files that are active as
+	 * they can create inconsistent archive copies.
+	 */
+	if (cpcnt != arcn->sb.st_size)
+		paxwarn(1, "File changed size %s", arcn->org_name);
+	else if (fstat(fd, &sb) == -1)
+		syswarn(1, errno, "Failed stat on %s", arcn->org_name);
+	else if (timespeccmp(&arcn->sb.st_mtim, &sb.st_mtim, !=))
+		paxwarn(1, "File %s was modified during read", arcn->org_name);
+	else if (lseek(fd, 0, SEEK_SET) < 0)
+		syswarn(1, errno, "File rewind failed on: %s", arcn->org_name);
+	else {
+		arcn->crc = crc;
+		return(0);
+	}
+	return(-1);
+}