bsdtar now uses the "tree" package instead of "fts" for walking

directory heirarchies.

1 files changed, 506 insertions, 0 deletions

diff --git a/usr.bin/tar/tree.c b/usr.bin/tar/tree.c
new file mode 100644
index 0000000..0fc3584
--- /dev/null
+++ b/usr.bin/tar/tree.c
@@ -0,0 +1,506 @@
+/*-
+ * Copyright (c) 2003-2004 Tim Kientzle
+ * All rights reserved.
+ *
+ * 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
+ *    in this position and unchanged.
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``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 AUTHOR(S) 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.
+ */
+
+/*-
+ * This is a new directory-walking system that addresses a number
+ * of problems I've had with fts(3).  In particular, it has no
+ * pathname-length limits (other than the size of 'int'), handles
+ * deep logical traversals, uses considerably less memory, and has
+ * an opaque interface (easier to modify in the future).
+ *
+ * Internally, it keeps a single list of "tree_entry" items that
+ * represent filesystem objects that require further attention.
+ * Non-directories are not kept in memory: they are pulled from
+ * readdir(), returned to the client, then freed as soon as possible.
+ * Any directory entry to be traversed gets pushed onto the stack.
+ *
+ * There is surprisingly little information that needs to be kept for
+ * each item on the stack.  Just the name, depth (represented here as the
+ * string length of the parent directory's pathname), and some markers
+ * indicating how to get back to the parent (via chdir("..") for a
+ * regular dir or via fchdir(2) for a symlink).
+ */
+#include "bsdtar_platform.h"
+__FBSDID("$FreeBSD$");
+
+#include <sys/stat.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "tree.h"
+
+/*
+ * TODO:
+ *    1) Loop checking.
+ *    3) Arbitrary logical traversals by closing/reopening intermediate fds.
+ */
+
+struct tree_entry {
+	struct tree_entry *next;
+	struct tree_entry *parent;
+	char *name;
+	size_t dirname_length;
+	dev_t dev;
+	ino_t ino;
+	int fd;
+	int flags;
+};
+
+/* Definitions for tree_entry.flags bitmap. */
+#define	isDir 1 /* This entry is a regular directory. */
+#define	isDirLink 2 /* This entry is a symbolic link to a directory. */
+#define	needsPreVisit 4 /* This entry needs to be previsited. */
+#define	needsPostVisit 8 /* This entry needs to be postvisited. */
+
+/*
+ * Local data for this package.
+ */
+struct tree {
+	struct tree_entry	*stack;
+	struct tree_entry	*current;
+	DIR	*d;
+	int	 initialDirFd;
+	int	 flags;
+	int	 visit_type;
+	int	 tree_errno; /* Error code from last failed operation. */
+
+	char	*buff;
+	const char	*basename;
+	size_t	 buff_length;
+	size_t	 path_length;
+	size_t	 dirname_length;
+
+	int	 depth;
+	int	 openCount;
+	int	 maxOpenCount;
+
+	struct stat	lst;
+	struct stat	st;
+};
+
+/* Definitions for tree.flags bitmap. */
+#define needsReturn 8  /* Marks first entry as not having been returned yet. */
+#define hasStat 16  /* The st entry is set. */
+#define hasLstat 32 /* The lst entry is set. */
+
+
+#ifdef HAVE_DIRENT_D_NAMLEN
+/* BSD extension; avoids need for a strlen() call. */
+#define D_NAMELEN(dp)	(dp)->d_namlen
+#else
+#define D_NAMELEN(dp)	(strlen((dp)->d_name))
+#endif
+
+#if 0
+#include <stdio.h>
+void
+tree_dump(struct tree *t, FILE *out)
+{
+	struct tree_entry *te;
+
+	fprintf(out, "\tdepth: %d\n", t->depth);
+	fprintf(out, "\tbuff: %s\n", t->buff);
+	fprintf(out, "\tpwd: "); fflush(stdout); system("pwd");
+	fprintf(out, "\taccess: %s\n", t->basename);
+	fprintf(out, "\tstack:\n");
+	for(te = t->stack; te != NULL; te = te->next) {
+		fprintf(out, "\t\tte->name: %s%s%s\n", te->name,
+		    te->flags & needsPreVisit ? "" : " *",
+		    t->current == te ? " (current)" : "");
+	}
+}
+#endif
+
+/*
+ * Add a directory path to the current stack.
+ */
+static void
+tree_push(struct tree *t, const char *path)
+{
+	struct tree_entry *te;
+
+	te = malloc(sizeof(*te));
+	memset(te, 0, sizeof(*te));
+	te->next = t->stack;
+	t->stack = te;
+	te->fd = -1;
+	te->name = strdup(path);
+	te->flags = needsPreVisit | needsPostVisit;
+	te->dirname_length = t->dirname_length;
+}
+
+/*
+ * Append a name to the current path.
+ */
+static void
+tree_append(struct tree *t, const char *name, size_t name_length)
+{
+	char *p;
+
+	if (t->buff != NULL)
+		t->buff[t->dirname_length] = '\0';
+	/* Strip trailing '/' from name, unless entire name is "/". */
+	while (name_length > 1 && name[name_length - 1] == '/')
+		name_length--;
+
+	/* Resize pathname buffer as needed. */
+	while (name_length + 1 + t->dirname_length >= t->buff_length) {
+		t->buff_length *= 2;
+		if (t->buff_length < 1024)
+			t->buff_length = 1024;
+		t->buff = realloc(t->buff, t->buff_length);
+	}
+	p = t->buff + t->dirname_length;
+	t->path_length = t->dirname_length + name_length;
+	/* Add a separating '/' if it's needed. */
+	if (t->dirname_length > 0 && p[-1] != '/') {
+		*p++ = '/';
+		t->path_length ++;
+	}
+	strncpy(p, name, name_length);
+	p[name_length] = '\0';
+	t->basename = p;
+}
+
+/*
+ * Open a directory tree for traversal.
+ */
+struct tree *
+tree_open(const char *path)
+{
+	struct tree *t;
+
+	t = malloc(sizeof(*t));
+	memset(t, 0, sizeof(*t));
+	tree_append(t, path, strlen(path));
+	t->initialDirFd = open(".", O_RDONLY);
+	/*
+	 * During most of the traversal, items are set up and then
+	 * returned immediately from tree_next().  That doesn't work
+	 * for the very first entry, so we set a flag for this special
+	 * case.
+	 */
+	t->flags = needsReturn;
+	return (t);
+}
+
+/*
+ * We've finished a directory; ascend back to the parent.
+ */
+static void
+tree_ascend(struct tree *t)
+{
+	struct tree_entry *te;
+
+	te = t->stack;
+	t->depth--;
+	if (te->flags & isDirLink) {
+		fchdir(te->fd);
+		close(te->fd);
+		t->openCount--;
+	} else {
+		chdir("..");
+	}
+}
+
+/*
+ * Pop the working stack.
+ */
+static void
+tree_pop(struct tree *t)
+{
+	struct tree_entry *te;
+
+	t->buff[t->dirname_length] = '\0';
+	if (t->stack == t->current && t->current != NULL)
+		t->current = t->current->parent;
+	te = t->stack;
+	t->stack = te->next;
+	t->dirname_length = te->dirname_length;
+	t->basename = t->buff + t->dirname_length;
+	/* Special case: starting dir doesn't skip leading '/'. */
+	if (t->dirname_length > 0)
+		t->basename++;
+	free(te->name);
+	free(te);
+}
+
+/*
+ * Get the next item in the tree traversal.
+ */
+int
+tree_next(struct tree *t)
+{
+	struct dirent *de = NULL;
+
+	/* Handle the startup case by returning the initial entry. */
+	if (t->flags & needsReturn) {
+		t->flags &= ~needsReturn;
+		return (t->visit_type = TREE_REGULAR);
+	}
+
+	while (t->stack != NULL) {
+		/* If there's an open dir, get the next entry from there. */
+		while (t->d != NULL) {
+			de = readdir(t->d);
+			if (de == NULL) {
+				closedir(t->d);
+				t->d = NULL;
+			} else if (de->d_name[0] == '.'
+			    && de->d_name[1] == '\0') {
+				/* Skip '.' */
+			} else if (de->d_name[0] == '.'
+			    && de->d_name[1] == '.'
+			    && de->d_name[2] == '\0') {
+				/* Skip '..' */
+			} else {
+				/*
+				 * Append the path to the current path
+				 * and return it.
+				 */
+				tree_append(t, de->d_name, D_NAMELEN(de));
+				t->flags &= ~hasLstat;
+				t->flags &= ~hasStat;
+				return (t->visit_type = TREE_REGULAR);
+			}
+		}
+
+		/* If the current dir needs to be visited, set it up. */
+		if (t->stack->flags & needsPreVisit) {
+			t->current = t->stack;
+			tree_append(t, t->stack->name, strlen(t->stack->name));
+			t->stack->flags &= ~needsPreVisit;
+			/* If it is a link, set up fd for the ascent. */
+			if (t->stack->flags & isDirLink) {
+				t->stack->fd = open(".", O_RDONLY);
+				t->openCount++;
+				if (t->openCount > t->maxOpenCount)
+					t->maxOpenCount = t->openCount;
+			}
+			t->dirname_length = t->path_length;
+			if (chdir(t->stack->name) != 0) {
+				/* chdir() failed; return error */
+				tree_pop(t);
+				t->tree_errno = errno;
+				return (t->visit_type = TREE_ERROR);
+			}
+			t->d = opendir(".");
+			if (t->d == NULL) {
+				tree_pop(t);
+				t->tree_errno = errno;
+				return (t->visit_type = TREE_ERROR);
+			}
+			t->depth++;
+			t->flags &= ~hasLstat;
+			t->flags &= ~hasStat;
+			t->basename = ".";
+			return (t->visit_type = TREE_POSTDESCENT);
+		}
+
+		/* We've done everything necessary for the top stack entry. */
+		if (t->stack->flags & needsPostVisit) {
+			tree_ascend(t);
+			tree_pop(t);
+			t->flags &= ~hasLstat;
+			t->flags &= ~hasStat;
+			return (t->visit_type = TREE_POSTASCENT);
+		}
+	}
+	return (t->visit_type = 0);
+}
+
+/*
+ * Return error code.
+ */
+int
+tree_errno(struct tree *t)
+{
+	return (t->tree_errno);
+}
+
+/*
+ * Called by the client to mark the directory just returned from
+ * tree_next() as needing to be visited.
+ */
+void
+tree_descend(struct tree *t)
+{
+	if (t->visit_type != TREE_REGULAR)
+		return;
+
+	if (tree_current_is_physical_dir(t)) {
+		tree_push(t, t->basename);
+		t->stack->flags |= isDir;
+	} else if (tree_current_is_dir(t)) {
+		tree_push(t, t->basename);
+		t->stack->flags |= isDirLink;
+	}
+}
+
+/*
+ * Get the stat() data for the entry just returned from tree_next().
+ */
+const struct stat *
+tree_current_stat(struct tree *t)
+{
+	if (!(t->flags & hasStat)) {
+		if (stat(t->basename, &t->st) != 0)
+			return NULL;
+		t->flags |= hasStat;
+	}
+	return (&t->st);
+}
+
+/*
+ * Get the lstat() data for the entry just returned from tree_next().
+ */
+const struct stat *
+tree_current_lstat(struct tree *t)
+{
+	if (!(t->flags & hasLstat)) {
+		if (lstat(t->basename, &t->lst) != 0)
+			return NULL;
+		t->flags |= hasLstat;
+	}
+	return (&t->lst);
+}
+
+/*
+ * Test whether current entry is a dir or dir link.
+ */
+int
+tree_current_is_dir(struct tree *t)
+{
+	/* If we've already pulled stat(), just use that. */
+	if (t->flags & hasStat)
+		return (S_ISDIR(tree_current_stat(t)->st_mode));
+
+	/* If we've already pulled lstat(), we may be able to use that. */
+	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))
+			return 1;
+		/* If it's not a dir and not a link, we're done. */
+		if (!S_ISLNK(tree_current_lstat(t)->st_mode))
+			return 0;
+		/*
+		 * If the above two tests fail, then it's a link, but
+		 * we don't know whether it's a link to a dir or a
+		 * non-dir.
+		 */
+	}
+
+	/* TODO: Use a more efficient mechanism when available. */
+	return (S_ISDIR(tree_current_stat(t)->st_mode));
+}
+
+/*
+ * Test whether current entry is a physical directory.
+ */
+int
+tree_current_is_physical_dir(struct tree *t)
+{
+	/* If we've already pulled lstat(), just use that. */
+	if (t->flags & hasLstat)
+		return (S_ISDIR(tree_current_lstat(t)->st_mode));
+
+	/* TODO: Use a more efficient mechanism when available. */
+	return (S_ISDIR(tree_current_lstat(t)->st_mode));
+}
+
+/*
+ * Test whether current entry is a symbolic link.
+ */
+int
+tree_current_is_physical_link(struct tree *t)
+{
+	/* If we've already pulled lstat(), just use that. */
+	if (t->flags & hasLstat)
+		return (S_ISLNK(tree_current_lstat(t)->st_mode));
+
+	/* TODO: Use a more efficient mechanism when available. */
+	return (S_ISLNK(tree_current_lstat(t)->st_mode));
+}
+
+/*
+ * Return the access path for the entry just returned from tree_next().
+ */
+const char *
+tree_current_access_path(struct tree *t)
+{
+	return (t->basename);
+}
+
+/*
+ * Return the full path for the entry just returned from tree_next().
+ */
+const char *
+tree_current_path(struct tree *t)
+{
+	return (t->buff);
+}
+
+/*
+ * Return the length of the path for the entry just returned from tree_next().
+ */
+size_t
+tree_current_pathlen(struct tree *t)
+{
+	return (t->path_length);
+}
+
+/*
+ * Return the nesting depth of the entry just returned from tree_next().
+ */
+int
+tree_current_depth(struct tree *t)
+{
+	return (t->depth);
+}
+
+/*
+ * Terminate the traversal and release any resources.
+ */
+void
+tree_close(struct tree *t)
+{
+	/* Release anything remaining in the stack. */
+	while (t->stack != NULL)
+		tree_pop(t);
+	if (t->buff)
+		free(t->buff);
+	/* chdir() back to where we started. */
+	if (t->initialDirFd >= 0) {
+		fchdir(t->initialDirFd);
+		close(t->initialDirFd);
+		t->initialDirFd = -1;
+	}
+	free(t);
+}