From: Michihiro NAKAJIMA <ggcueroad@gmail.com>
Date: Wed, 15 Feb 2012 11:14:48 +0000 (+0900)
Subject: Improve directory traversals on POSIX system. Delay changing a working
X-Git-Tag: v3.0.4~2^2~89
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=3439b41d9252372753dc8ca2c7b3e6c0dcfc2874;p=thirdparty%2Flibarchive.git

Improve directory traversals on POSIX system. Delay changing a working
directory until it's really needed and avoid unnecessary changing
directories.
---

diff --git a/libarchive/archive_read_disk_entry_from_file.c b/libarchive/archive_read_disk_entry_from_file.c
index 201ea42f5..d5d9eaae7 100644
--- a/libarchive/archive_read_disk_entry_from_file.c
+++ b/libarchive/archive_read_disk_entry_from_file.c
@@ -1,6 +1,6 @@
 /*-
  * Copyright (c) 2003-2009 Tim Kientzle
- * Copyright (c) 2010 Michihiro NAKAJIMA
+ * Copyright (c) 2010-2012 Michihiro NAKAJIMA
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -115,13 +115,13 @@ __FBSDID("$FreeBSD: head/lib/libarchive/archive_read_disk_entry_from_file.c 2010
 #endif
 
 static int setup_acls_posix1e(struct archive_read_disk *,
-    struct archive_entry *, int fd);
+    struct archive_entry *, int *fd);
 static int setup_mac_metadata(struct archive_read_disk *,
-    struct archive_entry *, int fd);
+    struct archive_entry *, int *fd);
 static int setup_xattrs(struct archive_read_disk *,
-    struct archive_entry *, int fd);
+    struct archive_entry *, int *fd);
 static int setup_sparse(struct archive_read_disk *,
-    struct archive_entry *, int fd);
+    struct archive_entry *, int *fd);
 
 int
 archive_read_disk_entry_from_file(struct archive *_a,
@@ -189,8 +189,13 @@ archive_read_disk_entry_from_file(struct archive *_a,
 	 * this is an extra step, it has a nice side-effect: We get an
 	 * open file descriptor which we can use in the subsequent lookups. */
 	if ((S_ISREG(st->st_mode) || S_ISDIR(st->st_mode))) {
-		if (fd < 0)
-			fd = open(path, O_RDONLY | O_NONBLOCK);
+		if (fd < 0) {
+			if (a->tree != NULL)
+				fd = a->open_on_current_dir(a->tree, path,
+					O_RDONLY | O_NONBLOCK);
+			else
+				fd = open(path, O_RDONLY | O_NONBLOCK);
+		}
 		if (fd >= 0) {
 			unsigned long stflags;
 			r = ioctl(fd, EXT2_IOC_GETFLAGS, &stflags);
@@ -212,13 +217,21 @@ archive_read_disk_entry_from_file(struct archive *_a,
 			    "Couldn't read link data");
 			return (ARCHIVE_FAILED);
 		}
+		if (a->tree != NULL) {
 #ifdef HAVE_READLINKAT
-		if (a->entry_wd_fd >= 0)
-			lnklen = readlinkat(a->entry_wd_fd, path,
-			    linkbuffer, linkbuffer_len);
-		else
+			lnklen = readlinkat(a->tree_current_dir_fd(a->tree),
+			    path, linkbuffer, linkbuffer_len);
+#else
+			if (a->tree_enter_working_dir(a->tree) != 0) {
+				archive_set_error(&a->archive, errno,
+				    "Couldn't read link data");
+				free(linkbuffer);
+				return (ARCHIVE_FAILED);
+			}
+			lnklen = readlink(path, linkbuffer, linkbuffer_len);
 #endif /* HAVE_READLINKAT */
-		lnklen = readlink(path, linkbuffer, linkbuffer_len);
+		} else
+			lnklen = readlink(path, linkbuffer, linkbuffer_len);
 		if (lnklen < 0) {
 			archive_set_error(&a->archive, errno,
 			    "Couldn't read link data");
@@ -231,16 +244,16 @@ archive_read_disk_entry_from_file(struct archive *_a,
 	}
 #endif /* HAVE_READLINK || HAVE_READLINKAT */
 
-	r = setup_acls_posix1e(a, entry, fd);
-	r1 = setup_xattrs(a, entry, fd);
+	r = setup_acls_posix1e(a, entry, &fd);
+	r1 = setup_xattrs(a, entry, &fd);
 	if (r1 < r)
 		r = r1;
 	if (a->enable_copyfile) {
-		r1 = setup_mac_metadata(a, entry, fd);
+		r1 = setup_mac_metadata(a, entry, &fd);
 		if (r1 < r)
 			r = r1;
 	}
-	r1 = setup_sparse(a, entry, fd);
+	r1 = setup_sparse(a, entry, &fd);
 	if (r1 < r)
 		r = r1;
 
@@ -266,7 +279,7 @@ archive_read_disk_entry_from_file(struct archive *_a,
  */
 static int
 setup_mac_metadata(struct archive_read_disk *a,
-    struct archive_entry *entry, int fd)
+    struct archive_entry *entry, int *fd)
 {
 	int tempfd = -1;
 	int copyfile_flags = COPYFILE_NOFOLLOW | COPYFILE_ACL | COPYFILE_XATTR;
@@ -276,6 +289,7 @@ setup_mac_metadata(struct archive_read_disk *a,
 	int have_attrs;
 	const char *name, *tempdir, *tempfile = NULL;
 
+	(void)fd; /* UNUSED */
 	name = archive_entry_sourcepath(entry);
 	if (name == NULL)
 		name = archive_entry_pathname(entry);
@@ -285,6 +299,14 @@ setup_mac_metadata(struct archive_read_disk *a,
 		return (ARCHIVE_WARN);
 	}
 
+	if (a->tree != NULL) {
+		if (a->tree_enter_working_dir(a->tree) != 0) {
+			archive_set_error(&a->archive, errno,
+				    "Couldn't change dir");
+				return (ARCHIVE_FAILED);
+		}
+	}
+
 	/* Short-circuit if there's nothing to do. */
 	have_attrs = copyfile(name, NULL, 0, copyfile_flags | COPYFILE_CHECK);
 	if (have_attrs == -1) {
@@ -355,7 +377,7 @@ cleanup:
  */
 static int
 setup_mac_metadata(struct archive_read_disk *a,
-    struct archive_entry *entry, int fd)
+    struct archive_entry *entry, int *fd)
 {
 	(void)a; /* UNUSED */
 	(void)entry; /* UNUSED */
@@ -371,7 +393,7 @@ static void setup_acl_posix1e(struct archive_read_disk *a,
 
 static int
 setup_acls_posix1e(struct archive_read_disk *a,
-    struct archive_entry *entry, int fd)
+    struct archive_entry *entry, int *fd)
 {
 	const char	*accpath;
 	acl_t		 acl;
@@ -382,9 +404,20 @@ setup_acls_posix1e(struct archive_read_disk *a,
 
 	archive_entry_acl_clear(entry);
 
+	if (*fd < 0 && a->tree != NULL &&
+	    (a->follow_symlinks || archive_entry_filetype(entry) != AE_IFLNK)){
+		*fd = a->open_on_current_dir(a->tree, accpath,
+				O_RDONLY | O_NONBLOCK);
+		if (*fd < 0) {
+			archive_set_error(&a->archive, errno,
+			    "Couldn't access %s", accpath);
+			return (ARCHIVE_FAILED);
+		}
+	}
+
 	/* Retrieve access ACL from file. */
-	if (fd >= 0)
-		acl = acl_get_fd(fd);
+	if (*fd >= 0)
+		acl = acl_get_fd(*fd);
 #if HAVE_ACL_GET_LINK_NP
 	else if (!a->follow_symlinks)
 		acl = acl_get_link_np(accpath, ACL_TYPE_ACCESS);
@@ -478,7 +511,7 @@ setup_acl_posix1e(struct archive_read_disk *a,
 #else
 static int
 setup_acls_posix1e(struct archive_read_disk *a,
-    struct archive_entry *entry, int fd)
+    struct archive_entry *entry, int *fd)
 {
 	(void)a;      /* UNUSED */
 	(void)entry;  /* UNUSED */
@@ -572,7 +605,7 @@ setup_xattr(struct archive_read_disk *a,
 
 static int
 setup_xattrs(struct archive_read_disk *a,
-    struct archive_entry *entry, int fd)
+    struct archive_entry *entry, int *fd)
 {
 	char *list, *p;
 	const char *path;
@@ -582,16 +615,30 @@ setup_xattrs(struct archive_read_disk *a,
 	if (path == NULL)
 		path = archive_entry_pathname(entry);
 
+	if (*fd < 0 && a->tree != NULL) {
+		if (a->follow_symlinks ||
+		    archive_entry_filetype(entry) != AE_IFLNK)
+			*fd = a->open_on_current_dir(a->tree, path,
+				O_RDONLY | O_NONBLOCK);
+		if (*fd < 0) {
+			if (a->tree_enter_working_dir(a->tree) != 0) {
+				archive_set_error(&a->archive, errno,
+				    "Couldn't access %s", path);
+				return (ARCHIVE_FAILED);
+			}
+		}
+	}
+
 #if HAVE_FLISTXATTR
-	if (fd >= 0)
-		list_size = flistxattr(fd, NULL, 0);
+	if (*fd >= 0)
+		list_size = flistxattr(*fd, NULL, 0);
 	else if (!a->follow_symlinks)
 		list_size = llistxattr(path, NULL, 0);
 	else
 		list_size = listxattr(path, NULL, 0);
 #elif HAVE_FLISTEA
-	if (fd >= 0)
-		list_size = flistea(fd, NULL, 0);
+	if (*fd >= 0)
+		list_size = flistea(*fd, NULL, 0);
 	else if (!a->follow_symlinks)
 		list_size = llistea(path, NULL, 0);
 	else
@@ -615,15 +662,15 @@ setup_xattrs(struct archive_read_disk *a,
 	}
 
 #if HAVE_FLISTXATTR
-	if (fd >= 0)
-		list_size = flistxattr(fd, list, list_size);
+	if (*fd >= 0)
+		list_size = flistxattr(*fd, list, list_size);
 	else if (!a->follow_symlinks)
 		list_size = llistxattr(path, list, list_size);
 	else
 		list_size = listxattr(path, list, list_size);
 #elif HAVE_FLISTEA
-	if (fd >= 0)
-		list_size = flistea(fd, list, list_size);
+	if (*fd >= 0)
+		list_size = flistea(*fd, list, list_size);
 	else if (!a->follow_symlinks)
 		list_size = llistea(path, list, list_size);
 	else
@@ -641,7 +688,7 @@ setup_xattrs(struct archive_read_disk *a,
 		if (strncmp(p, "system.", 7) == 0 ||
 				strncmp(p, "xfsroot.", 8) == 0)
 			continue;
-		setup_xattr(a, entry, p, fd);
+		setup_xattr(a, entry, p, *fd);
 	}
 
 	free(list);
@@ -715,7 +762,7 @@ setup_xattr(struct archive_read_disk *a, struct archive_entry *entry,
 
 static int
 setup_xattrs(struct archive_read_disk *a,
-    struct archive_entry *entry, int fd)
+    struct archive_entry *entry, int *fd)
 {
 	char buff[512];
 	char *list, *p;
@@ -727,8 +774,22 @@ setup_xattrs(struct archive_read_disk *a,
 	if (path == NULL)
 		path = archive_entry_pathname(entry);
 
-	if (fd >= 0)
-		list_size = extattr_list_fd(fd, namespace, NULL, 0);
+	if (*fd < 0 && a->tree != NULL) {
+		if (a->follow_symlinks ||
+		    archive_entry_filetype(entry) != AE_IFLNK)
+			*fd = a->open_on_current_dir(a->tree, path,
+				O_RDONLY | O_NONBLOCK);
+		if (*fd < 0) {
+			if (a->tree_enter_working_dir(a->tree) != 0) {
+				archive_set_error(&a->archive, errno,
+				    "Couldn't access %s", path);
+				return (ARCHIVE_FAILED);
+			}
+		}
+	}
+
+	if (*fd >= 0)
+		list_size = extattr_list_fd(*fd, namespace, NULL, 0);
 	else if (!a->follow_symlinks)
 		list_size = extattr_list_link(path, namespace, NULL, 0);
 	else
@@ -750,8 +811,8 @@ setup_xattrs(struct archive_read_disk *a,
 		return (ARCHIVE_FATAL);
 	}
 
-	if (fd >= 0)
-		list_size = extattr_list_fd(fd, namespace, list, list_size);
+	if (*fd >= 0)
+		list_size = extattr_list_fd(*fd, namespace, list, list_size);
 	else if (!a->follow_symlinks)
 		list_size = extattr_list_link(path, namespace, list, list_size);
 	else
@@ -773,7 +834,7 @@ setup_xattrs(struct archive_read_disk *a,
 		name = buff + strlen(buff);
 		memcpy(name, p + 1, len);
 		name[len] = '\0';
-		setup_xattr(a, entry, namespace, name, buff, fd);
+		setup_xattr(a, entry, namespace, name, buff, *fd);
 		p += 1 + len;
 	}
 
@@ -788,7 +849,7 @@ setup_xattrs(struct archive_read_disk *a,
  */
 static int
 setup_xattrs(struct archive_read_disk *a,
-    struct archive_entry *entry, int fd)
+    struct archive_entry *entry, int *fd)
 {
 	(void)a;     /* UNUSED */
 	(void)entry; /* UNUSED */
@@ -817,14 +878,13 @@ setup_xattrs(struct archive_read_disk *a,
 
 static int
 setup_sparse(struct archive_read_disk *a,
-    struct archive_entry *entry, int fd)
+    struct archive_entry *entry, int *fd)
 {
 	char buff[4096];
 	struct fiemap *fm;
 	struct fiemap_extent *fe;
 	int64_t size;
 	int count, do_fiemap;
-	int initial_fd = fd;
 	int exit_sts = ARCHIVE_OK;
 
 	if (archive_entry_filetype(entry) != AE_IFREG
@@ -832,14 +892,18 @@ setup_sparse(struct archive_read_disk *a,
 	    || archive_entry_hardlink(entry) != NULL)
 		return (ARCHIVE_OK);
 
-	if (fd < 0) {
+	if (*fd < 0) {
 		const char *path;
 
 		path = archive_entry_sourcepath(entry);
 		if (path == NULL)
 			path = archive_entry_pathname(entry);
-		fd = open(path, O_RDONLY | O_NONBLOCK);
-		if (fd < 0) {
+		if (a->tree != NULL) {
+			*fd = a->open_on_current_dir(a->tree, path,
+				O_RDONLY | O_NONBLOCK);
+		else
+			*fd = open(path, O_RDONLY | O_NONBLOCK);
+		if (*fd < 0) {
 			archive_set_error(&a->archive, errno,
 			    "Can't open `%s'", path);
 			return (ARCHIVE_FAILED);
@@ -857,7 +921,7 @@ setup_sparse(struct archive_read_disk *a,
 	for (;;) {
 		int i, r;
 
-		r = ioctl(fd, FS_IOC_FIEMAP, fm); 
+		r = ioctl(*fd, FS_IOC_FIEMAP, fm); 
 		if (r < 0) {
 			/* When something error happens, it is better we
 			 * should return ARCHIVE_OK because an earlier
@@ -893,8 +957,6 @@ setup_sparse(struct archive_read_disk *a,
 			break;
 	}
 exit_setup_sparse:
-	if (initial_fd != fd)
-		close(fd);
 	return (exit_sts);
 }
 
@@ -906,10 +968,9 @@ exit_setup_sparse:
 
 static int
 setup_sparse(struct archive_read_disk *a,
-    struct archive_entry *entry, int fd)
+    struct archive_entry *entry, int *fd)
 {
 	int64_t size;
-	int initial_fd = fd;
 	off_t initial_off; /* FreeBSD/Solaris only, so off_t okay here */
 	off_t off_s, off_e; /* FreeBSD/Solaris only, so off_t okay here */
 	int exit_sts = ARCHIVE_OK;
@@ -920,22 +981,45 @@ setup_sparse(struct archive_read_disk *a,
 		return (ARCHIVE_OK);
 
 	/* Does filesystem support the reporting of hole ? */
-	if (fd >= 0) {
-		if (fpathconf(fd, _PC_MIN_HOLE_SIZE) <= 0)
+	if (*fd < 0 && a->tree != NULL) {
+		const char *path;
+
+		path = archive_entry_sourcepath(entry);
+		if (path == NULL)
+			path = archive_entry_pathname(entry);
+		*fd = a->open_on_current_dir(a->tree, path,
+				O_RDONLY | O_NONBLOCK);
+		if (*fd < 0) {
+			archive_set_error(&a->archive, errno,
+			    "Can't open `%s'", path);
+			return (ARCHIVE_FAILED);
+		}
+	}
+
+	if (*fd >= 0) {
+		if (fpathconf(*fd, _PC_MIN_HOLE_SIZE) <= 0)
 			return (ARCHIVE_OK);
-		initial_off = lseek(fd, 0, SEEK_CUR);
+		initial_off = lseek(*fd, 0, SEEK_CUR);
 		if (initial_off != 0)
-			lseek(fd, 0, SEEK_SET);
+			lseek(*fd, 0, SEEK_SET);
 	} else {
 		const char *path;
 
+		if (a->tree != NULL) {
+			if (a->tree_enter_working_dir(a->tree) != 0) {
+				archive_set_error(&a->archive, errno,
+				    "Couldn't change dir");
+				return (ARCHIVE_FAILED);
+			}
+		}
 		path = archive_entry_sourcepath(entry);
 		if (path == NULL)
 			path = archive_entry_pathname(entry);
+			
 		if (pathconf(path, _PC_MIN_HOLE_SIZE) <= 0)
 			return (ARCHIVE_OK);
-		fd = open(path, O_RDONLY | O_NONBLOCK);
-		if (fd < 0) {
+		*fd = open(path, O_RDONLY | O_NONBLOCK);
+		if (*fd < 0) {
 			archive_set_error(&a->archive, errno,
 			    "Can't open `%s'", path);
 			return (ARCHIVE_FAILED);
@@ -946,7 +1030,7 @@ setup_sparse(struct archive_read_disk *a,
 	off_s = 0;
 	size = archive_entry_size(entry);
 	while (off_s < size) {
-		off_s = lseek(fd, off_s, SEEK_DATA);
+		off_s = lseek(*fd, off_s, SEEK_DATA);
 		if (off_s == (off_t)-1) {
 			if (errno == ENXIO)
 				break;/* no more hole */
@@ -955,10 +1039,10 @@ setup_sparse(struct archive_read_disk *a,
 			exit_sts = ARCHIVE_FAILED;
 			goto exit_setup_sparse;
 		}
-		off_e = lseek(fd, off_s, SEEK_HOLE);
+		off_e = lseek(*fd, off_s, SEEK_HOLE);
 		if (off_s == (off_t)-1) {
 			if (errno == ENXIO) {
-				off_e = lseek(fd, 0, SEEK_END);
+				off_e = lseek(*fd, 0, SEEK_END);
 				if (off_e != (off_t)-1)
 					break;/* no more data */
 			}
@@ -974,10 +1058,7 @@ setup_sparse(struct archive_read_disk *a,
 		off_s = off_e;
 	}
 exit_setup_sparse:
-	if (initial_fd != fd)
-		close(fd);
-	else
-		lseek(fd, initial_off, SEEK_SET);
+	lseek(*fd, initial_off, SEEK_SET);
 	return (exit_sts);
 }
 
@@ -988,7 +1069,7 @@ exit_setup_sparse:
  */
 static int
 setup_sparse(struct archive_read_disk *a,
-    struct archive_entry *entry, int fd)
+    struct archive_entry *entry, int *fd)
 {
 	(void)a;     /* UNUSED */
 	(void)entry; /* UNUSED */
diff --git a/libarchive/archive_read_disk_posix.c b/libarchive/archive_read_disk_posix.c
index fa2a0a403..cebb30545 100644
--- a/libarchive/archive_read_disk_posix.c
+++ b/libarchive/archive_read_disk_posix.c
@@ -257,6 +257,7 @@ struct tree {
 #define	onWorkingDir	64 /* We are on the working dir where we are
 			    * reading directory entry at this time. */
 #define	needsRestoreTimes 128
+#define	onInitialDir	256 /* We are on the initial dir. */
 
 static int
 tree_dir_next_posix(struct tree *t);
@@ -359,6 +360,7 @@ static const char *trivial_lookup_uname(void *, int64_t uid);
 static int	setup_sparse(struct archive_read_disk *, struct archive_entry *);
 static int	close_and_restore_time(int fd, struct tree *,
 		    struct restore_time *);
+static int	open_on_current_dir(struct tree *, const char *, int);
 
 
 static struct archive_vtable *
@@ -457,7 +459,9 @@ archive_read_disk_new(void)
 	a->lookup_gname = trivial_lookup_gname;
 	a->enable_copyfile = 1;
 	a->traverse_mount_points = 1;
-	a->entry_wd_fd = -1;
+	a->open_on_current_dir = open_on_current_dir;
+	a->tree_current_dir_fd = tree_current_dir_fd;
+	a->tree_enter_working_dir = tree_enter_working_dir;
 	return (&a->archive);
 }
 
@@ -734,13 +738,8 @@ _archive_read_data_block(struct archive *_a, const void **buff,
 			flags |= O_NOATIME;
 		do {
 #endif
-#ifdef HAVE_OPENAT
-			t->entry_fd = openat(tree_current_dir_fd(t),
+			t->entry_fd = open_on_current_dir(t,
 			    tree_current_access_path(t), flags);
-#else
-			tree_enter_working_dir(t);
-			t->entry_fd = open(tree_current_access_path(t), flags);
-#endif
 #if defined(O_NOATIME)
 			/*
 			 * When we did open the file with O_NOATIME flag,
@@ -869,10 +868,6 @@ _archive_read_next_header2(struct archive *_a, struct archive_entry *entry)
 		close_and_restore_time(t->entry_fd, t, &t->restore_time);
 		t->entry_fd = -1;
 	}
-#if !(defined(HAVE_OPENAT) && defined(HAVE_FSTATAT) && defined(HAVE_FDOPENDIR))
-	/* Restore working directory. */
-	tree_enter_working_dir(t);
-#endif
 
 next_entry:
 	st = NULL;
@@ -1007,15 +1002,8 @@ next_entry:
 		if (S_ISREG(st->st_mode) || S_ISDIR(st->st_mode)) {
 			unsigned long stflags;
 
-#if defined(HAVE_OPENAT) && defined(HAVE_FSTATAT) && defined(HAVE_FDOPENDIR)
-			fd = openat(tree_current_dir_fd(t),
+			fd = open_on_current_dir(t,
 			    tree_current_access_path(t), O_RDONLY | O_NONBLOCK);
-#else
-			tree_enter_working_dir(t);
-			fd = open(tree_current_access_path(t),
-			    O_RDONLY | O_NONBLOCK);
-			
-#endif
 			if (fd >= 0) {
 				r = ioctl(fd, EXT2_IOC_GETFLAGS, &stflags);
 				if (r == 0 && (stflags & EXT2_NODUMP_FL) != 0) {
@@ -1096,26 +1084,6 @@ next_entry:
 		}
 	}
 
-#if defined(HAVE_OPENAT) && defined(HAVE_FSTATAT) && defined(HAVE_FDOPENDIR)
-	/*
-	 * Open the current file to freely gather its metadata anywhere in
-	 * working directory.
-	 * Note: A symbolic link file cannot be opened with O_NOFOLLOW.
-	 */
-	if (fd < 0 && archive_entry_filetype(entry) != AE_IFLNK)
-		fd = openat(tree_current_dir_fd(t), tree_current_access_path(t),
-		    O_RDONLY | O_NONBLOCK);
-	/* Restore working directory if openat() operation failed or
-	 * the file is a symbolic link. */
-	if (fd < 0)
-		tree_enter_working_dir(t);
-
-	/* The current direcotry fd is needed at
-	 * archive_read_disk_entry_from_file() function to read link data
-	 * with readlinkat(). */
-	a->entry_wd_fd = tree_current_dir_fd(t);
-#endif
-
 	/*
 	 * Populate the archive_entry with metadata from the disk.
 	 */
@@ -1499,7 +1467,7 @@ setup_current_filesystem(struct archive_read_disk *a)
 	t->current_filesystem->synthetic = -1;
 	t->current_filesystem->remote = -1;
 	if (tree_current_is_symblic_link_target(t)) {
-#if defined(HAVE_OPENAT) && defined(HAVE_FSTATAT) && defined(HAVE_FDOPENDIR)
+#if defined(HAVE_OPENAT)
 		/*
 		 * Get file system statistics on any directory
 		 * where current is.
@@ -1516,6 +1484,10 @@ setup_current_filesystem(struct archive_read_disk *a)
 			xr = get_xfer_size(t, fd, NULL);
 		close(fd);
 #else
+		if (tree_enter_working_dir(t) != 0) {
+			archive_set_error(&a->archive, errno, "fchdir failed");
+			return (ARCHIVE_FAILED);
+		}
 		r = statfs(tree_current_access_path(t), &sfs);
 		if (r == 0)
 			xr = get_xfer_size(t, -1, tree_current_access_path(t));
@@ -1665,7 +1637,7 @@ setup_current_filesystem(struct archive_read_disk *a)
 	int r, vr = 0, xr = 0;
 
 	if (tree_current_is_symblic_link_target(t)) {
-#if defined(HAVE_OPENAT) && defined(HAVE_FSTATAT) && defined(HAVE_FDOPENDIR)
+#if defined(HAVE_OPENAT)
 		/*
 		 * Get file system statistics on any directory
 		 * where current is.
@@ -1683,6 +1655,10 @@ setup_current_filesystem(struct archive_read_disk *a)
 			xr = get_xfer_size(t, fd, NULL);
 		close(fd);
 #else
+		if (tree_enter_working_dir(t) != 0) {
+			archive_set_error(&a->archive, errno, "fchdir failed");
+			return (ARCHIVE_FAILED);
+		}
 		vr = statvfs(tree_current_access_path(t), &svfs);
 		r = statfs(tree_current_access_path(t), &sfs);
 		if (r == 0)
@@ -1694,9 +1670,11 @@ setup_current_filesystem(struct archive_read_disk *a)
 		r = fstatfs(tree_current_dir_fd(t), &sfs);
 		if (r == 0)
 			xr = get_xfer_size(t, tree_current_dir_fd(t), NULL);
-#elif defined(HAVE_OPENAT) && defined(HAVE_FSTATAT) && defined(HAVE_FDOPENDIR)
-#error "Unexpected case. Please tell us about this error."
 #else
+		if (tree_enter_working_dir(t) != 0) {
+			archive_set_error(&a->archive, errno, "fchdir failed");
+			return (ARCHIVE_FAILED);
+		}
 		vr = statvfs(".", &svfs);
 		r = statfs(".", &sfs);
 		if (r == 0)
@@ -1767,7 +1745,7 @@ setup_current_filesystem(struct archive_read_disk *a)
 	t->current_filesystem->synthetic = -1;/* Not supported */
 	t->current_filesystem->remote = -1;/* Not supported */
 	if (tree_current_is_symblic_link_target(t)) {
-#if defined(HAVE_OPENAT) && defined(HAVE_FSTATAT) && defined(HAVE_FDOPENDIR)
+#if defined(HAVE_OPENAT)
 		/*
 		 * Get file system statistics on any directory
 		 * where current is.
@@ -1784,6 +1762,10 @@ setup_current_filesystem(struct archive_read_disk *a)
 			xr = get_xfer_size(t, fd, NULL);
 		close(fd);
 #else
+		if (tree_enter_working_dir(t) != 0) {
+			archive_set_error(&a->archive, errno, "fchdir failed");
+			return (ARCHIVE_FAILED);
+		}
 		r = statvfs(tree_current_access_path(t), &sfs);
 		if (r == 0)
 			xr = get_xfer_size(t, -1, tree_current_access_path(t));
@@ -1793,9 +1775,11 @@ setup_current_filesystem(struct archive_read_disk *a)
 		r = fstatvfs(tree_current_dir_fd(t), &sfs);
 		if (r == 0)
 			xr = get_xfer_size(t, tree_current_dir_fd(t), NULL);
-#elif defined(HAVE_OPENAT) && defined(HAVE_FSTATAT) && defined(HAVE_FDOPENDIR)
-#error "Unexpected case. Please tell us about this error."
 #else
+		if (tree_enter_working_dir(t) != 0) {
+			archive_set_error(&a->archive, errno, "fchdir failed");
+			return (ARCHIVE_FAILED);
+		}
 		r = statvfs(".", &sfs);
 		if (r == 0)
 			xr = get_xfer_size(t, -1, ".");
@@ -1935,6 +1919,18 @@ close_and_restore_time(int fd, struct tree *t, struct restore_time *rt)
 	return (0);
 }
 
+static int
+open_on_current_dir(struct tree *t, const char *path, int flags)
+{
+#ifdef HAVE_OPENAT
+	return (openat(tree_current_dir_fd(t), path, flags));
+#else
+	if (tree_enter_working_dir(t) != 0)
+		return (-1);
+	return (open(path, flags));
+#endif
+}
+
 /*
  * Add a directory path to the current stack.
  */
@@ -2016,6 +2012,7 @@ static struct tree *
 tree_reopen(struct tree *t, const char *path, int restore_time)
 {
 	t->flags = (restore_time)?needsRestoreTimes:0;
+	t->flags |= onInitialDir;
 	t->visit_type = 0;
 	t->tree_errno = 0;
 	t->dirname_length = 0;
@@ -2049,17 +2046,7 @@ tree_descent(struct tree *t)
 #if defined(O_DIRECTORY)
 	flag |= O_DIRECTORY;
 #endif
-#if defined(HAVE_OPENAT) && defined(HAVE_FSTATAT) && defined(HAVE_FDOPENDIR)
-	new_fd = openat(t->working_dir_fd, t->stack->name.s, flag);
-#else
-	new_fd = open(t->stack->name.s, flag);
-	if (new_fd >= 0) {
-		if (fchdir(new_fd) != 0) {
-			close(new_fd);
-			new_fd = -1;
-		}
-	}
-#endif
+	new_fd = open_on_current_dir(t, t->stack->name.s, flag);
 	if (new_fd < 0) {
 		t->tree_errno = errno;
 		r = TREE_ERROR_DIR;
@@ -2073,7 +2060,9 @@ tree_descent(struct tree *t)
 				t->maxOpenCount = t->openCount;
 		} else
 			close(t->working_dir_fd);
+		/* Renew the current working directory. */
 		t->working_dir_fd = new_fd;
+		t->flags &= ~onWorkingDir;
 	}
 	return (r);
 }
@@ -2089,29 +2078,17 @@ tree_ascend(struct tree *t)
 
 	te = t->stack;
 	prev_dir_fd = t->working_dir_fd;
-#if defined(HAVE_OPENAT) && defined(HAVE_FSTATAT) && defined(HAVE_FDOPENDIR)
 	if (te->flags & isDirLink)
 		new_fd = te->symlink_parent_fd;
 	else
-		new_fd = openat(t->working_dir_fd, "..", O_RDONLY);
-#else
-	if (te->flags & isDirLink)
-		new_fd = te->symlink_parent_fd;
-	else
-		new_fd = open("..", O_RDONLY);
-	if (new_fd >= 0) {
-		if (fchdir(new_fd) != 0) {
-			if ((te->flags & isDirLink) == 0)
-				close(new_fd);
-			new_fd = -1;
-		}
-	}
-#endif
+		new_fd = open_on_current_dir(t, "..", O_RDONLY);
 	if (new_fd < 0) {
 		t->tree_errno = errno;
 		r = TREE_ERROR_FATAL;
 	} else {
+		/* Renew the current working directory. */
 		t->working_dir_fd = new_fd;
+		t->flags &= ~onWorkingDir;
 		/* Current directory has been changed, we should
 		 * close an fd of previous working directory. */
 		close_and_restore_time(prev_dir_fd, t, &te->restore_time);
@@ -2132,10 +2109,12 @@ tree_enter_initial_dir(struct tree *t)
 {
 	int r = 0;
 
-	if (t->flags & onWorkingDir) {
+	if ((t->flags & onInitialDir) == 0) {
 		r = fchdir(t->initial_dir_fd);
-		if (r == 0)
+		if (r == 0) {
 			t->flags &= ~onWorkingDir;
+			t->flags |= onInitialDir;
+		}
 	}
 	return (r);
 }
@@ -2155,8 +2134,10 @@ tree_enter_working_dir(struct tree *t)
 	 */
 	if (t->depth > 0 && (t->flags & onWorkingDir) == 0) {
 		r = fchdir(t->working_dir_fd);
-		if (r == 0)
+		if (r == 0) {
+			t->flags &= ~onInitialDir;
 			t->flags |= onWorkingDir;
+		}
 	}
 	return (r);
 }
@@ -2265,7 +2246,8 @@ tree_dir_next_posix(struct tree *t)
 #if defined(HAVE_FDOPENDIR)
 		if ((t->d = fdopendir(dup(t->working_dir_fd))) == NULL) {
 #else
-		if ((t->d = opendir(".")) == NULL) {
+		if (tree_enter_working_dir(t) != 0 ||
+		    (t->d = opendir(".")) == NULL) {
 #endif
 			r = tree_ascend(t); /* Undo "chdir" */
 			tree_pop(t);
@@ -2336,6 +2318,8 @@ tree_current_stat(struct tree *t)
 		if (fstatat(tree_current_dir_fd(t),
 		    tree_current_access_path(t), &t->st, 0) != 0)
 #else
+		if (tree_enter_working_dir(t) != 0)
+			return NULL;
 		if (stat(tree_current_access_path(t), &t->st) != 0)
 #endif
 			return NULL;
@@ -2356,6 +2340,8 @@ tree_current_lstat(struct tree *t)
 		    tree_current_access_path(t), &t->lst,
 		    AT_SYMLINK_NOFOLLOW) != 0)
 #else
+		if (tree_enter_working_dir(t) != 0)
+			return NULL;
 		if (lstat(tree_current_access_path(t), &t->lst) != 0)
 #endif
 			return NULL;
@@ -2377,7 +2363,10 @@ tree_current_is_dir(struct tree *t)
 	 */
 	if (t->flags & hasLstat) {
 		/* If lstat() says it's a dir, it must be a dir. */
-		if (S_ISDIR(tree_current_lstat(t)->st_mode))
+		st = tree_current_lstat(t);
+		if (st == NULL)
+			return 0;
+		if (S_ISDIR(st->st_mode))
 			return 1;
 		/* Not a dir; might be a link to a dir. */
 		/* If it's not a link, then it's not a link to a dir. */
@@ -2411,9 +2400,13 @@ tree_current_is_physical_dir(struct tree *t)
 	 * If stat() says it isn't a dir, then it's not a dir.
 	 * If stat() data is cached, this check is free, so do it first.
 	 */
-	if ((t->flags & hasStat)
-	    && (!S_ISDIR(tree_current_stat(t)->st_mode)))
-		return 0;
+	if (t->flags & hasStat) {
+		st = tree_current_stat(t);
+		if (st == NULL)
+			return (0);
+		if (!S_ISDIR(st->st_mode))
+			return (0);
+	}
 
 	/*
 	 * Either stat() said it was a dir (in which case, we have
@@ -2457,7 +2450,7 @@ tree_current_is_symblic_link_target(struct tree *t)
 
 	lst = tree_current_lstat(t);
 	st = tree_current_stat(t);
-	return (st != NULL &&
+	return (st != NULL && lst != NULL &&
 	    (int64_t)st->st_dev == t->current_filesystem->dev &&
 	    st->st_dev != lst->st_dev);
 }
diff --git a/libarchive/archive_read_disk_private.h b/libarchive/archive_read_disk_private.h
index fa73a2410..e5af16b91 100644
--- a/libarchive/archive_read_disk_private.h
+++ b/libarchive/archive_read_disk_private.h
@@ -56,6 +56,9 @@ struct archive_read_disk {
 
 	/* Directory traversals. */
 	struct tree *tree;
+	int	(*open_on_current_dir)(struct tree*, const char *, int);
+	int	(*tree_current_dir_fd)(struct tree*);
+	int	(*tree_enter_working_dir)(struct tree*);
 
 	/* Set 1 if users request to restore atime . */
 	int		 restore_time;
@@ -66,8 +69,6 @@ struct archive_read_disk {
 	/* Set 1 if users request to traverse mount points. */
 	int		 traverse_mount_points;
 
-	int		 entry_wd_fd;
-
 	const char * (*lookup_gname)(void *private, int64_t gid);
 	void	(*cleanup_gname)(void *private);
 	void	 *lookup_gname_data;