Adding upstream version 1:4.13+dfsg1.upstream/1%4.13+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 968 insertions, 0 deletions

diff --git a/libmisc/copydir.c b/libmisc/copydir.c
new file mode 100644
index 0000000..b692aa9
--- /dev/null
+++ b/libmisc/copydir.c
@@ -0,0 +1,968 @@
+/*
+ * SPDX-FileCopyrightText: 1991 - 1994, Julianne Frances Haugh
+ * SPDX-FileCopyrightText: 1996 - 2001, Marek Michałkiewicz
+ * SPDX-FileCopyrightText: 2003 - 2006, Tomasz Kłoczko
+ * SPDX-FileCopyrightText: 2007 - 2010, Nicolas François
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <config.h>
+
+#ident "$Id$"
+
+#include <assert.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include "prototypes.h"
+#include "defines.h"
+#ifdef WITH_SELINUX
+#include <selinux/selinux.h>
+#endif				/* WITH_SELINUX */
+#if defined(WITH_ACL) || defined(WITH_ATTR)
+#include <stdarg.h>
+#include <attr/error_context.h>
+#endif				/* WITH_ACL || WITH_ATTR */
+#ifdef WITH_ACL
+#include <acl/libacl.h>
+#endif				/* WITH_ACL */
+#ifdef WITH_ATTR
+#include <attr/libattr.h>
+#endif				/* WITH_ATTR */
+#include "shadowlog.h"
+
+
+static /*@null@*/const char *src_orig;
+static /*@null@*/const char *dst_orig;
+
+struct link_name {
+	dev_t ln_dev;
+	ino_t ln_ino;
+	nlink_t ln_count;
+	char *ln_name;
+	/*@dependent@*/struct link_name *ln_next;
+};
+static /*@exposed@*/struct link_name *links;
+
+struct path_info {
+	const char *full_path;
+	int dirfd;
+	const char *name;
+};
+
+static int copy_entry (const struct path_info *src, const struct path_info *dst,
+                       bool reset_selinux,
+                       uid_t old_uid, uid_t new_uid,
+                       gid_t old_gid, gid_t new_gid);
+static int copy_dir (const struct path_info *src, const struct path_info *dst,
+                     bool reset_selinux,
+                     const struct stat *statp, const struct timespec mt[],
+                     uid_t old_uid, uid_t new_uid,
+                     gid_t old_gid, gid_t new_gid);
+static /*@null@*/char *readlink_malloc (const char *filename);
+static int copy_symlink (const struct path_info *src, const struct path_info *dst,
+                         unused bool reset_selinux,
+                         const struct stat *statp, const struct timespec mt[],
+                         uid_t old_uid, uid_t new_uid,
+                         gid_t old_gid, gid_t new_gid);
+static int copy_hardlink (const struct path_info *dst,
+                          unused bool reset_selinux,
+                          struct link_name *lp);
+static int copy_special (const struct path_info *src, const struct path_info *dst,
+                         bool reset_selinux,
+                         const struct stat *statp, const struct timespec mt[],
+                         uid_t old_uid, uid_t new_uid,
+                         gid_t old_gid, gid_t new_gid);
+static int copy_file (const struct path_info *src, const struct path_info *dst,
+                      bool reset_selinux,
+                      const struct stat *statp, const struct timespec mt[],
+                      uid_t old_uid, uid_t new_uid,
+                      gid_t old_gid, gid_t new_gid);
+static int chownat_if_needed (const struct path_info *dst, const struct stat *statp,
+                            uid_t old_uid, uid_t new_uid,
+                            gid_t old_gid, gid_t new_gid);
+static int fchown_if_needed (int fdst, const struct stat *statp,
+                             uid_t old_uid, uid_t new_uid,
+                             gid_t old_gid, gid_t new_gid);
+
+#if defined(WITH_ACL) || defined(WITH_ATTR)
+/*
+ * error_acl - format the error messages for the ACL and EQ libraries.
+ */
+format_attr(printf, 2, 3)
+static void error_acl (unused struct error_context *ctx, const char *fmt, ...)
+{
+	va_list ap;
+	FILE *shadow_logfd = log_get_logfd();
+
+	/* ignore the case when destination does not support ACLs
+	 * or extended attributes */
+	if (ENOTSUP == errno) {
+		errno = 0;
+		return;
+	}
+
+	va_start (ap, fmt);
+	(void) fprintf (shadow_logfd, _("%s: "), log_get_progname());
+	if (vfprintf (shadow_logfd, fmt, ap) != 0) {
+		(void) fputs (_(": "), shadow_logfd);
+	}
+	(void) fprintf (shadow_logfd, "%s\n", strerror (errno));
+	va_end (ap);
+}
+
+static struct error_context ctx = {
+	error_acl, NULL, NULL
+};
+#endif				/* WITH_ACL || WITH_ATTR */
+
+#ifdef WITH_ACL
+static int perm_copy_path(const struct path_info *src,
+						  const struct path_info *dst,
+						  struct error_context *errctx)
+{
+	int src_fd, dst_fd, ret;
+
+	src_fd = openat(src->dirfd, src->name, O_RDONLY | O_NOFOLLOW | O_NONBLOCK | O_CLOEXEC);
+	if (src_fd < 0) {
+		return -1;
+	}
+
+	dst_fd = openat(dst->dirfd, dst->name, O_RDONLY | O_NOFOLLOW | O_NONBLOCK | O_CLOEXEC);
+	if (dst_fd < 0) {
+		(void) close (src_fd);
+		return -1;
+	}
+
+	ret = perm_copy_fd(src->full_path, src_fd, dst->full_path, dst_fd, errctx);
+	(void) close (src_fd);
+	(void) close (dst_fd);
+	return ret;
+}
+#endif				/* WITH_ACL */
+
+#ifdef WITH_ATTR
+static int attr_copy_path(const struct path_info *src,
+						  const struct path_info *dst,
+						  int (*callback) (const char *, struct error_context *),
+						  struct error_context *errctx)
+{
+	int src_fd, dst_fd, ret;
+
+	src_fd = openat(src->dirfd, src->name, O_RDONLY | O_NOFOLLOW | O_NONBLOCK | O_CLOEXEC);
+	if (src_fd < 0) {
+		return -1;
+	}
+
+	dst_fd = openat(dst->dirfd, dst->name, O_RDONLY | O_NOFOLLOW | O_NONBLOCK | O_CLOEXEC);
+	if (dst_fd < 0) {
+		(void) close (src_fd);
+		return -1;
+	}
+
+	ret = attr_copy_fd(src->full_path, src_fd, dst->full_path, dst_fd, callback, errctx);
+	(void) close (src_fd);
+	(void) close (dst_fd);
+	return ret;
+}
+#endif				/* WITH_ATTR */
+
+/*
+ * remove_link - delete a link from the linked list
+ */
+static void remove_link (/*@only@*/struct link_name *ln)
+{
+	struct link_name *lp;
+
+	if (links == ln) {
+		links = ln->ln_next;
+		free (ln->ln_name);
+		free (ln);
+		return;
+	}
+	for (lp = links; NULL !=lp; lp = lp->ln_next) {
+		if (lp->ln_next == ln) {
+			break;
+		}
+	}
+
+	if (NULL == lp) {
+		free (ln->ln_name);
+		free (ln);
+		return;
+	}
+
+	lp->ln_next = lp->ln_next->ln_next;
+	free (ln->ln_name);
+	free (ln);
+}
+
+/*
+ * check_link - see if a file is really a link
+ */
+
+static /*@exposed@*/ /*@null@*/struct link_name *check_link (const char *name, const struct stat *sb)
+{
+	struct link_name *lp;
+	size_t src_len;
+	size_t dst_len;
+	size_t name_len;
+	size_t len;
+
+	/* copy_tree () must be the entry point */
+	assert (NULL != src_orig);
+	assert (NULL != dst_orig);
+
+	for (lp = links; NULL != lp; lp = lp->ln_next) {
+		if ((lp->ln_dev == sb->st_dev) && (lp->ln_ino == sb->st_ino)) {
+			return lp;
+		}
+	}
+
+	if (sb->st_nlink == 1) {
+		return NULL;
+	}
+
+	lp = (struct link_name *) xmalloc (sizeof *lp);
+	src_len = strlen (src_orig);
+	dst_len = strlen (dst_orig);
+	name_len = strlen (name);
+	lp->ln_dev = sb->st_dev;
+	lp->ln_ino = sb->st_ino;
+	lp->ln_count = sb->st_nlink;
+	len = name_len - src_len + dst_len + 1;
+	lp->ln_name = (char *) xmalloc (len);
+	(void) snprintf (lp->ln_name, len, "%s%s", dst_orig, name + src_len);
+	lp->ln_next = links;
+	links = lp;
+
+	return NULL;
+}
+
+static int copy_tree_impl (const struct path_info *src, const struct path_info *dst,
+               bool copy_root, bool reset_selinux,
+               uid_t old_uid, uid_t new_uid,
+               gid_t old_gid, gid_t new_gid)
+{
+	int dst_fd, src_fd, err = 0;
+	bool set_orig = false;
+	const struct dirent *ent;
+	DIR *dir;
+
+	if (copy_root) {
+		struct stat sb;
+
+		if (   fstatat (dst->dirfd, dst->name, &sb, 0) == 0
+		    || errno != ENOENT) {
+			return -1;
+		}
+
+		if (fstatat (src->dirfd, src->name, &sb, AT_SYMLINK_NOFOLLOW) == -1) {
+			return -1;
+		}
+
+		if (!S_ISDIR (sb.st_mode)) {
+			fprintf (log_get_logfd(),
+			         "%s: %s is not a directory",
+			         log_get_progname(), src->full_path);
+			return -1;
+		}
+
+		return copy_entry (src, dst, reset_selinux,
+		                   old_uid, new_uid, old_gid, new_gid);
+	}
+
+	/*
+	 * Make certain both directories exist.  This routine is called
+	 * after the home directory is created, or recursively after the
+	 * target is created.  It assumes the target directory exists.
+	 */
+
+	src_fd = openat (src->dirfd, src->name, O_DIRECTORY | O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
+	if (src_fd < 0) {
+		return -1;
+	}
+
+	dst_fd = openat (dst->dirfd, dst->name, O_DIRECTORY | O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
+	if (dst_fd < 0) {
+		(void) close (src_fd);
+		return -1;
+	}
+
+	/*
+	 * Open the source directory and read each entry.  Every file
+	 * entry in the directory is copied with the UID and GID set
+	 * to the provided values.  As an added security feature only
+	 * regular files (and directories ...) are copied, and no file
+	 * is made set-ID.
+	 */
+	dir = fdopendir (src_fd);
+	if (NULL == dir) {
+		(void) close (src_fd);
+		(void) close (dst_fd);
+		return -1;
+	}
+
+	if (src_orig == NULL) {
+		src_orig = src->full_path;
+		dst_orig = dst->full_path;
+		set_orig = true;
+	}
+	while ((0 == err) && (ent = readdir (dir)) != NULL) {
+		/*
+		 * Skip the "." and ".." entries
+		 */
+		if ((strcmp (ent->d_name, ".") != 0) &&
+		    (strcmp (ent->d_name, "..") != 0)) {
+			char *src_name;
+			char *dst_name;
+			size_t src_len = strlen (ent->d_name) + 2;
+			size_t dst_len = strlen (ent->d_name) + 2;
+			src_len += strlen (src->full_path);
+			dst_len += strlen (dst->full_path);
+
+			src_name = (char *) malloc (src_len);
+			dst_name = (char *) malloc (dst_len);
+
+			if ((NULL == src_name) || (NULL == dst_name)) {
+				err = -1;
+			} else {
+				/*
+				 * Build the filename for both the source and
+				 * the destination files.
+				 */
+				struct path_info src_entry, dst_entry;
+
+				(void) snprintf (src_name, src_len, "%s/%s",
+				                 src->full_path, ent->d_name);
+				(void) snprintf (dst_name, dst_len, "%s/%s",
+				                 dst->full_path, ent->d_name);
+
+				src_entry.full_path = src_name;
+				src_entry.dirfd = dirfd(dir);
+				src_entry.name = ent->d_name;
+
+				dst_entry.full_path = dst_name;
+				dst_entry.dirfd = dst_fd;
+				dst_entry.name = ent->d_name;
+
+				err = copy_entry (&src_entry, &dst_entry,
+				                  reset_selinux,
+				                  old_uid, new_uid,
+				                  old_gid, new_gid);
+			}
+			free (src_name);
+			free (dst_name);
+		}
+	}
+	(void) closedir (dir);
+	(void) close (dst_fd);
+
+	if (set_orig) {
+		src_orig = NULL;
+		dst_orig = NULL;
+		/* FIXME: clean links
+		 * Since there can be hardlinks elsewhere on the device,
+		 * we cannot check that all the hardlinks were found:
+		assert (NULL == links);
+		 */
+	}
+
+#ifdef WITH_SELINUX
+	/* Reset SELinux to create files with default contexts.
+	 * Note that the context is only reset on exit of copy_tree (it is
+	 * assumed that the program would quit without needing a restored
+	 * context if copy_tree failed previously), and that copy_tree can
+	 * be called recursively (hence the context is set on the
+	 * sub-functions of copy_entry).
+	 */
+	if (reset_selinux_file_context () != 0) {
+		err = -1;
+	}
+#endif				/* WITH_SELINUX */
+
+	return err;
+}
+
+/*
+ * copy_entry - copy the entry of a directory
+ *
+ *	Copy the entry src to dst.
+ *	Depending on the type of entry, this function will forward the
+ *	request to copy_dir(), copy_symlink(), copy_hardlink(),
+ *	copy_special(), or copy_file().
+ *
+ *	The access and modification time will not be modified.
+ *
+ *	The permissions will be set to new_uid/new_gid.
+ *
+ *	If new_uid (resp. new_gid) is equal to -1, the user (resp. group) will
+ *	not be modified.
+ *
+ *	Only the files owned (resp. group-owned) by old_uid (resp.
+ *	old_gid) will be modified, unless old_uid (resp. old_gid) is set
+ *	to -1.
+ */
+static int copy_entry (const struct path_info *src, const struct path_info *dst,
+                       bool reset_selinux,
+                       uid_t old_uid, uid_t new_uid,
+                       gid_t old_gid, gid_t new_gid)
+{
+	int err = 0;
+	struct stat sb;
+	struct link_name *lp;
+	struct timespec mt[2];
+
+	if (fstatat(src->dirfd, src->name, &sb, AT_SYMLINK_NOFOLLOW) == -1) {
+		/* If we cannot stat the file, do not care. */
+	} else {
+#ifdef HAVE_STRUCT_STAT_ST_ATIM
+		mt[0].tv_sec  = sb.st_atim.tv_sec;
+		mt[0].tv_nsec = sb.st_atim.tv_nsec;
+#else				/* !HAVE_STRUCT_STAT_ST_ATIM */
+		mt[0].tv_sec  = sb.st_atime;
+# ifdef HAVE_STRUCT_STAT_ST_ATIMENSEC
+		mt[0].tv_nsec = sb.st_atimensec;
+# else				/* !HAVE_STRUCT_STAT_ST_ATIMENSEC */
+		mt[0].tv_nsec = 0;
+# endif				/* !HAVE_STRUCT_STAT_ST_ATIMENSEC */
+#endif				/* !HAVE_STRUCT_STAT_ST_ATIM */
+
+#ifdef HAVE_STRUCT_STAT_ST_MTIM
+		mt[1].tv_sec  = sb.st_mtim.tv_sec;
+		mt[1].tv_nsec = sb.st_mtim.tv_nsec;
+#else				/* !HAVE_STRUCT_STAT_ST_MTIM */
+		mt[1].tv_sec  = sb.st_mtime;
+# ifdef HAVE_STRUCT_STAT_ST_MTIMENSEC
+		mt[1].tv_nsec = sb.st_mtimensec;
+# else				/* !HAVE_STRUCT_STAT_ST_MTIMENSEC */
+		mt[1].tv_nsec = 0;
+# endif				/* !HAVE_STRUCT_STAT_ST_MTIMENSEC */
+#endif				/* !HAVE_STRUCT_STAT_ST_MTIM */
+
+		if (S_ISDIR (sb.st_mode)) {
+			err = copy_dir (src, dst, reset_selinux, &sb, mt,
+			                old_uid, new_uid, old_gid, new_gid);
+		}
+
+		/*
+		 * Copy any symbolic links
+		 */
+
+		else if (S_ISLNK (sb.st_mode)) {
+			err = copy_symlink (src, dst, reset_selinux, &sb, mt,
+			                    old_uid, new_uid, old_gid, new_gid);
+		}
+
+		/*
+		 * See if this is a previously copied link
+		 */
+
+		else if ((lp = check_link (src->full_path, &sb)) != NULL) {
+			err = copy_hardlink (dst, reset_selinux, lp);
+		}
+
+		/*
+		 * Deal with FIFOs and special files.  The user really
+		 * shouldn't have any of these, but it seems like it
+		 * would be nice to copy everything ...
+		 */
+
+		else if (!S_ISREG (sb.st_mode)) {
+			err = copy_special (src, dst, reset_selinux, &sb, mt,
+			                    old_uid, new_uid, old_gid, new_gid);
+		}
+
+		/*
+		 * Create the new file and copy the contents.  The new
+		 * file will be owned by the provided UID and GID values.
+		 */
+
+		else {
+			err = copy_file (src, dst, reset_selinux, &sb, mt,
+			                 old_uid, new_uid, old_gid, new_gid);
+		}
+	}
+
+	return err;
+}
+
+/*
+ * copy_dir - copy a directory
+ *
+ *	Copy a directory (recursively) from src to dst.
+ *
+ *	statp, mt, old_uid, new_uid, old_gid, and new_gid are used to set
+ *	the access and modification and the access rights.
+ *
+ *	Return 0 on success, -1 on error.
+ */
+static int copy_dir (const struct path_info *src, const struct path_info *dst,
+                     bool reset_selinux,
+                     const struct stat *statp, const struct timespec mt[],
+                     uid_t old_uid, uid_t new_uid,
+                     gid_t old_gid, gid_t new_gid)
+{
+	int err = 0;
+
+	/*
+	 * Create a new target directory, make it owned by
+	 * the user and then recursively copy that directory.
+	 */
+
+#ifdef WITH_SELINUX
+	if (set_selinux_file_context (dst->full_path, S_IFDIR) != 0) {
+		return -1;
+	}
+#endif				/* WITH_SELINUX */
+	if (   (mkdirat (dst->dirfd, dst->name, 0700) != 0)
+	    || (chownat_if_needed (dst, statp,
+	                         old_uid, new_uid, old_gid, new_gid) != 0)
+	    || (fchmodat (dst->dirfd, dst->name, statp->st_mode & 07777, AT_SYMLINK_NOFOLLOW) != 0)
+#ifdef WITH_ACL
+	    || (   (perm_copy_path (src, dst, &ctx) != 0)
+	        && (errno != 0))
+#endif				/* WITH_ACL */
+#ifdef WITH_ATTR
+	/*
+	 * If the third parameter is NULL, all extended attributes
+	 * except those that define Access Control Lists are copied.
+	 * ACLs are excluded by default because copying them between
+	 * file systems with and without ACL support needs some
+	 * additional logic so that no unexpected permissions result.
+	 */
+	    || (   !reset_selinux
+	        && (attr_copy_path (src, dst, NULL, &ctx) != 0)
+	        && (errno != 0))
+#endif				/* WITH_ATTR */
+	    || (copy_tree_impl (src, dst, false, reset_selinux,
+	                   old_uid, new_uid, old_gid, new_gid) != 0)
+	    || (utimensat (dst->dirfd, dst->name, mt, AT_SYMLINK_NOFOLLOW) != 0)) {
+		err = -1;
+	}
+
+	return err;
+}
+
+/*
+ * readlink_malloc - wrapper for readlink
+ *
+ * return NULL on error.
+ * The return string shall be freed by the caller.
+ */
+static /*@null@*/char *readlink_malloc (const char *filename)
+{
+	size_t size = 1024;
+
+	while (true) {
+		ssize_t nchars;
+		char *buffer = (char *) malloc (size);
+		if (NULL == buffer) {
+			return NULL;
+		}
+
+		nchars = readlink (filename, buffer, size);
+
+		if (nchars < 0) {
+			free(buffer);
+			return NULL;
+		}
+
+		if ((size_t) nchars < size) { /* The buffer was large enough */
+			/* readlink does not nul-terminate */
+			buffer[nchars] = '\0';
+			return buffer;
+		}
+
+		/* Try again with a bigger buffer */
+		free (buffer);
+		size *= 2;
+	}
+}
+
+/*
+ * copy_symlink - copy a symlink
+ *
+ *	Copy a symlink from src to dst.
+ *
+ *	statp, mt, old_uid, new_uid, old_gid, and new_gid are used to set
+ *	the access and modification and the access rights.
+ *
+ *	Return 0 on success, -1 on error.
+ */
+static int copy_symlink (const struct path_info *src, const struct path_info *dst,
+                         unused bool reset_selinux,
+                         const struct stat *statp, const struct timespec mt[],
+                         uid_t old_uid, uid_t new_uid,
+                         gid_t old_gid, gid_t new_gid)
+{
+	char *oldlink;
+
+	/* copy_tree () must be the entry point */
+	assert (NULL != src_orig);
+	assert (NULL != dst_orig);
+
+	/*
+	 * Get the name of the file which the link points
+	 * to.  If that name begins with the original
+	 * source directory name, that part of the link
+	 * name will be replaced with the original
+	 * destination directory name.
+	 */
+
+	oldlink = readlink_malloc (src->full_path);
+	if (NULL == oldlink) {
+		return -1;
+	}
+
+	/* If src was a link to an entry of the src_orig directory itself,
+	 * create a link to the corresponding entry in the dst_orig
+	 * directory.
+	 */
+	if (strncmp (oldlink, src_orig, strlen (src_orig)) == 0) {
+		size_t len = strlen (dst_orig) + strlen (oldlink) - strlen (src_orig) + 1;
+		char *dummy = (char *) xmalloc (len);
+		(void) snprintf (dummy, len, "%s%s",
+		                 dst_orig,
+		                 oldlink + strlen (src_orig));
+		free (oldlink);
+		oldlink = dummy;
+	}
+
+#ifdef WITH_SELINUX
+	if (set_selinux_file_context (dst->full_path, S_IFLNK) != 0) {
+		free (oldlink);
+		return -1;
+	}
+#endif				/* WITH_SELINUX */
+	if (   (symlinkat (oldlink, dst->dirfd, dst->name) != 0)
+	    || (chownat_if_needed (dst, statp,
+	                          old_uid, new_uid, old_gid, new_gid) != 0)) {
+		/* FIXME: there are no modes on symlinks, right?
+		 *        ACL could be copied, but this would be much more
+		 *        complex than calling perm_copy_file.
+		 *        Ditto for Extended Attributes.
+		 *        We currently only document that ACL and Extended
+		 *        Attributes are not copied.
+		 */
+		free (oldlink);
+		return -1;
+	}
+	free (oldlink);
+
+	if (utimensat (dst->dirfd, dst->name, mt, AT_SYMLINK_NOFOLLOW) != 0) {
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+ * copy_hardlink - copy a hardlink
+ *
+ *	Copy a hardlink from src to dst.
+ *
+ *	Return 0 on success, -1 on error.
+ */
+static int copy_hardlink (const struct path_info *dst,
+                          unused bool reset_selinux,
+                          struct link_name *lp)
+{
+	/* FIXME: selinux, ACL, Extended Attributes needed? */
+
+	if (linkat (AT_FDCWD, lp->ln_name, dst->dirfd, dst->name, 0) != 0) {
+		return -1;
+	}
+
+	/* If the file could be unlinked, decrement the links counter,
+	 * and forget about this link if it was the last reference */
+	lp->ln_count--;
+	if (lp->ln_count <= 0) {
+		remove_link (lp);
+	}
+
+	return 0;
+}
+
+/*
+ * copy_special - copy a special file
+ *
+ *	Copy a special file from src to dst.
+ *
+ *	statp, mt, old_uid, new_uid, old_gid, and new_gid are used to set
+ *	the access and modification and the access rights.
+ *
+ *	Return 0 on success, -1 on error.
+ */
+static int copy_special (const struct path_info *src, const struct path_info *dst,
+                         bool reset_selinux,
+                         const struct stat *statp, const struct timespec mt[],
+                         uid_t old_uid, uid_t new_uid,
+                         gid_t old_gid, gid_t new_gid)
+{
+	int err = 0;
+
+#ifdef WITH_SELINUX
+	if (set_selinux_file_context (dst->full_path, statp->st_mode & S_IFMT) != 0) {
+		return -1;
+	}
+#endif				/* WITH_SELINUX */
+
+	if (   (mknodat (dst->dirfd, dst->name, statp->st_mode & ~07777U, statp->st_rdev) != 0)
+	    || (chownat_if_needed (dst, statp,
+	                         old_uid, new_uid, old_gid, new_gid) != 0)
+	    || (fchmodat (dst->dirfd, dst->name, statp->st_mode & 07777, AT_SYMLINK_NOFOLLOW) != 0)
+#ifdef WITH_ACL
+	    || (   (perm_copy_path (src, dst, &ctx) != 0)
+	        && (errno != 0))
+#endif				/* WITH_ACL */
+#ifdef WITH_ATTR
+	/*
+	 * If the third parameter is NULL, all extended attributes
+	 * except those that define Access Control Lists are copied.
+	 * ACLs are excluded by default because copying them between
+	 * file systems with and without ACL support needs some
+	 * additional logic so that no unexpected permissions result.
+	 */
+	    || (   !reset_selinux
+	        && (attr_copy_path (src, dst, NULL, &ctx) != 0)
+	        && (errno != 0))
+#endif				/* WITH_ATTR */
+		|| (utimensat (dst->dirfd, dst->name, mt, AT_SYMLINK_NOFOLLOW) != 0)) {
+		err = -1;
+	}
+
+	return err;
+}
+
+/*
+ * full_write - write entire buffer
+ *
+ * Write up to count bytes from the buffer starting at buf to the
+ * file referred to by the file descriptor fd.
+ * Retry in case of a short write.
+ *
+ * Returns the number of bytes written on success, -1 on error.
+ */
+static ssize_t full_write(int fd, const void *buf, size_t count) {
+	ssize_t written = 0;
+
+	while (count > 0) {
+		ssize_t res;
+
+		res = write(fd, buf, count);
+		if (res < 0) {
+			if (errno == EINTR) {
+				continue;
+			}
+
+			return res;
+		}
+
+		if (res == 0) {
+			break;
+		}
+
+		written += res;
+		buf = (const unsigned char*)buf + res;
+		count -= (size_t)res;
+	}
+
+	return written;
+}
+
+/*
+ * copy_file - copy a file
+ *
+ *	Copy a file from src to dst.
+ *
+ *	statp, mt, old_uid, new_uid, old_gid, and new_gid are used to set
+ *	the access and modification and the access rights.
+ *
+ *	Return 0 on success, -1 on error.
+ */
+static int copy_file (const struct path_info *src, const struct path_info *dst,
+                      bool reset_selinux,
+                      const struct stat *statp, const struct timespec mt[],
+                      uid_t old_uid, uid_t new_uid,
+                      gid_t old_gid, gid_t new_gid)
+{
+	int err = 0;
+	int ifd;
+	int ofd;
+
+	ifd = openat (src->dirfd, src->name, O_RDONLY|O_NOFOLLOW|O_CLOEXEC);
+	if (ifd < 0) {
+		return -1;
+	}
+#ifdef WITH_SELINUX
+	if (set_selinux_file_context (dst->full_path, S_IFREG) != 0) {
+		(void) close (ifd);
+		return -1;
+	}
+#endif				/* WITH_SELINUX */
+	ofd = openat (dst->dirfd, dst->name, O_WRONLY | O_CREAT | O_EXCL | O_TRUNC | O_NOFOLLOW | O_CLOEXEC, 0600);
+	if (   (ofd < 0)
+	    || (fchown_if_needed (ofd, statp,
+	                          old_uid, new_uid, old_gid, new_gid) != 0)
+	    || (fchmod (ofd, statp->st_mode & 07777) != 0)
+#ifdef WITH_ACL
+	    || (   (perm_copy_fd (src->full_path, ifd, dst->full_path, ofd, &ctx) != 0)
+	        && (errno != 0))
+#endif				/* WITH_ACL */
+#ifdef WITH_ATTR
+	/*
+	 * If the third parameter is NULL, all extended attributes
+	 * except those that define Access Control Lists are copied.
+	 * ACLs are excluded by default because copying them between
+	 * file systems with and without ACL support needs some
+	 * additional logic so that no unexpected permissions result.
+	 */
+	    || (   !reset_selinux
+	        && (attr_copy_fd (src->full_path, ifd, dst->full_path, ofd, NULL, &ctx) != 0)
+	        && (errno != 0))
+#endif				/* WITH_ATTR */
+	   ) {
+		if (ofd >= 0) {
+			(void) close (ofd);
+		}
+		(void) close (ifd);
+		return -1;
+	}
+
+	while (true) {
+		char buf[8192];
+		ssize_t cnt;
+
+		cnt = read (ifd, buf, sizeof buf);
+		if (cnt < 0) {
+			if (errno == EINTR) {
+				continue;
+			}
+			(void) close (ofd);
+			(void) close (ifd);
+			return -1;
+		}
+		if (cnt == 0) {
+			break;
+		}
+
+		if (full_write (ofd, buf, (size_t)cnt) < 0) {
+			(void) close (ofd);
+			(void) close (ifd);
+			return -1;
+		}
+	}
+
+	(void) close (ifd);
+	if (close (ofd) != 0) {
+		return -1;
+	}
+
+	if (utimensat (dst->dirfd, dst->name, mt, AT_SYMLINK_NOFOLLOW) != 0) {
+		return -1;
+	}
+
+	return err;
+}
+
+#define def_chown_if_needed(chown_function, type_dst)                  \
+static int chown_function ## _if_needed (type_dst dst,                 \
+                                         const struct stat *statp,     \
+                                         uid_t old_uid, uid_t new_uid, \
+                                         gid_t old_gid, gid_t new_gid) \
+{                                                                      \
+	uid_t tmpuid = (uid_t) -1;                                     \
+	gid_t tmpgid = (gid_t) -1;                                     \
+                                                                       \
+	/* Use new_uid if old_uid is set to -1 or if the file was      \
+	 * owned by the user. */                                       \
+	if (((uid_t) -1 == old_uid) || (statp->st_uid == old_uid)) {   \
+		tmpuid = new_uid;                                      \
+	}                                                              \
+	/* Otherwise, or if new_uid was set to -1, we keep the same    \
+	 * owner. */                                                   \
+	if ((uid_t) -1 == tmpuid) {                                    \
+		tmpuid = statp->st_uid;                                \
+	}                                                              \
+                                                                       \
+	if (((gid_t) -1 == old_gid) || (statp->st_gid == old_gid)) {   \
+		tmpgid = new_gid;                                      \
+	}                                                              \
+	if ((gid_t) -1 == tmpgid) {                                    \
+		tmpgid = statp->st_gid;                                \
+	}                                                              \
+                                                                       \
+	return chown_function (dst, tmpuid, tmpgid);                   \
+}
+
+def_chown_if_needed (fchown, int)
+
+static int chownat_if_needed (const struct path_info *dst,
+							  const struct stat *statp,
+                              uid_t old_uid, uid_t new_uid,
+                              gid_t old_gid, gid_t new_gid)
+{
+	uid_t tmpuid = (uid_t) -1;
+	gid_t tmpgid = (gid_t) -1;
+
+	/* Use new_uid if old_uid is set to -1 or if the file was
+	 * owned by the user. */
+	if (((uid_t) -1 == old_uid) || (statp->st_uid == old_uid)) {
+		tmpuid = new_uid;
+	}
+	/* Otherwise, or if new_uid was set to -1, we keep the same
+	 * owner. */
+	if ((uid_t) -1 == tmpuid) {
+		tmpuid = statp->st_uid;
+	}
+
+	if (((gid_t) -1 == old_gid) || (statp->st_gid == old_gid)) {
+		tmpgid = new_gid;
+	}
+	if ((gid_t) -1 == tmpgid) {
+		tmpgid = statp->st_gid;
+	}
+
+	return fchownat (dst->dirfd, dst->name, tmpuid, tmpgid, AT_SYMLINK_NOFOLLOW);
+}
+
+/*
+ * copy_tree - copy files in a directory tree
+ *
+ *	copy_tree() walks a directory tree and copies ordinary files
+ *	as it goes.
+ *
+ *	When reset_selinux is enabled, extended attributes (and thus
+ *	SELinux attributes) are not copied.
+ *
+ *	old_uid and new_uid are used to set the ownership of the copied
+ *	files. Unless old_uid is set to -1, only the files owned by
+ *	old_uid have their ownership changed to new_uid. In addition, if
+ *	new_uid is set to -1, no ownership will be changed.
+ *
+ *	The same logic applies for the group-ownership and
+ *	old_gid/new_gid.
+ */
+int copy_tree (const char *src_root, const char *dst_root,
+               bool copy_root, bool reset_selinux,
+               uid_t old_uid, uid_t new_uid,
+               gid_t old_gid, gid_t new_gid)
+{
+	const struct path_info src = {
+		.full_path = src_root,
+		.dirfd = AT_FDCWD,
+		.name = src_root
+	};
+	const struct path_info dst = {
+		.full_path = dst_root,
+		.dirfd = AT_FDCWD,
+		.name = dst_root
+	};
+
+	return copy_tree_impl(&src, &dst, copy_root, reset_selinux,
+						  old_uid, new_uid, old_gid, new_gid);
+}