Add fstree like tree deserialization function to dir reader

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

2 files changed, 292 insertions, 1 deletions

diff --git a/lib/sqfs/Makemodule.am b/lib/sqfs/Makemodule.am
index 807c104..8dbb255 100644
--- a/lib/sqfs/Makemodule.am
+++ b/lib/sqfs/Makemodule.am
@@ -14,7 +14,7 @@ libsquashfs_la_SOURCES += lib/sqfs/read_inode.c lib/sqfs/write_inode.c
 libsquashfs_la_SOURCES += lib/sqfs/dir_writer.c lib/sqfs/xattr_reader.c
 libsquashfs_la_SOURCES += lib/sqfs/read_table.c lib/sqfs/comp/compressor.c
 libsquashfs_la_SOURCES += lib/sqfs/io_stdin.c lib/sqfs/comp/internal.h
-libsquashfs_la_SOURCES += lib/sqfs/dir_reader.c
+libsquashfs_la_SOURCES += lib/sqfs/dir_reader.c lib/sqfs/read_tree.c
 libsquashfs_la_SOURCES += lib/sqfs/blk_proc/process_block.c lib/sqfs/io.c
 libsquashfs_la_SOURCES += lib/sqfs/blk_proc/internal.h
 libsquashfs_la_CPPFLAGS = $(AM_CPPFLAGS)
diff --git a/lib/sqfs/read_tree.c b/lib/sqfs/read_tree.c
new file mode 100644
index 0000000..1cac26a
--- /dev/null
+++ b/lib/sqfs/read_tree.c
@@ -0,0 +1,291 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/*
+ * read_tree.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#define SQFS_BUILDING_DLL
+#include "config.h"
+
+#include "sqfs/meta_reader.h"
+#include "sqfs/compress.h"
+#include "sqfs/id_table.h"
+#include "sqfs/super.h"
+#include "sqfs/inode.h"
+#include "sqfs/error.h"
+#include "sqfs/dir.h"
+#include "util.h"
+
+#include <string.h>
+#include <stdlib.h>
+
+static int should_skip(int type, unsigned int flags)
+{
+	switch (type) {
+	case SQFS_INODE_BDEV:
+	case SQFS_INODE_CDEV:
+	case SQFS_INODE_EXT_CDEV:
+	case SQFS_INODE_EXT_BDEV:
+		return (flags & SQFS_TREE_NO_DEVICES);
+	case SQFS_INODE_SLINK:
+	case SQFS_INODE_EXT_SLINK:
+		return (flags & SQFS_TREE_NO_SLINKS);
+	case SQFS_INODE_SOCKET:
+	case SQFS_INODE_EXT_SOCKET:
+		return(flags & SQFS_TREE_NO_SOCKETS);
+	case SQFS_INODE_FIFO:
+	case SQFS_INODE_EXT_FIFO:
+		return (flags & SQFS_TREE_NO_FIFO);
+	}
+
+	return 0;
+}
+
+static bool would_be_own_parent(sqfs_tree_node_t *parent, sqfs_tree_node_t *n)
+{
+	uint32_t inum = n->inode->base.inode_number;
+
+	while (parent != NULL) {
+		if (parent->inode->base.inode_number == inum)
+			return true;
+
+		parent = parent->parent;
+	}
+
+	return false;
+}
+
+static sqfs_tree_node_t *create_node(sqfs_inode_generic_t *inode,
+				     const char *name)
+{
+	sqfs_tree_node_t *n;
+
+	n = alloc_flex(sizeof(*n), 1, strlen(name) + 1);
+	if (n == NULL)
+		return NULL;
+
+	n->inode = inode;
+	strcpy((char *)n->name, name);
+	return n;
+}
+
+static int fill_dir(sqfs_dir_reader_t *dr, sqfs_tree_node_t *root,
+		    unsigned int flags)
+{
+	sqfs_tree_node_t *n, *prev, **tail;
+	sqfs_inode_generic_t *inode;
+	sqfs_dir_entry_t *ent;
+	int err;
+
+	tail = &root->children;
+
+	for (;;) {
+		err = sqfs_dir_reader_read(dr, &ent);
+		if (err > 0)
+			break;
+		if (err < 0)
+			return err;
+
+		if (should_skip(ent->type, flags)) {
+			free(ent);
+			continue;
+		}
+
+		err = sqfs_dir_reader_get_inode(dr, &inode);
+		if (err) {
+			free(ent);
+			return err;
+		}
+
+		n = create_node(inode, (const char *)ent->name);
+		free(ent);
+
+		if (n == NULL) {
+			free(inode);
+			return SQFS_ERROR_ALLOC;
+		}
+
+		if (would_be_own_parent(root, n)) {
+			free(n);
+			free(inode);
+			return SQFS_ERROR_LINK_LOOP;
+		}
+
+		*tail = n;
+		tail = &n->next;
+		n->parent = root;
+	}
+
+	n = root->children;
+	prev = NULL;
+
+	while (n != NULL) {
+		if (n->inode->base.type == SQFS_INODE_DIR ||
+		    n->inode->base.type == SQFS_INODE_EXT_DIR) {
+			if (!(flags & SQFS_TREE_NO_RECURSE)) {
+				err = sqfs_dir_reader_open_dir(dr, n->inode);
+				if (err)
+					return err;
+
+				err = fill_dir(dr, n, flags);
+				if (err)
+					return err;
+			}
+
+			if (n->children == NULL &&
+			    (flags & SQFS_TREE_NO_EMPTY)) {
+				free(n->inode);
+				if (prev == NULL) {
+					root->children = n->next;
+					free(n);
+					n = root->children;
+				} else {
+					prev->next = n->next;
+					free(n);
+					n = prev->next;
+				}
+				continue;
+			}
+		}
+
+		prev = n;
+		n = n->next;
+	}
+
+	return 0;
+}
+
+static int resolve_ids(sqfs_tree_node_t *root, const sqfs_id_table_t *idtbl)
+{
+	sqfs_tree_node_t *it;
+	int err;
+
+	for (it = root->children; it != NULL; it = it->next)
+		resolve_ids(it, idtbl);
+
+	err = sqfs_id_table_index_to_id(idtbl, root->inode->base.uid_idx,
+					&root->uid);
+	if (err)
+		return err;
+
+	return sqfs_id_table_index_to_id(idtbl, root->inode->base.gid_idx,
+					 &root->gid);
+}
+
+void sqfs_dir_tree_destroy(sqfs_tree_node_t *root)
+{
+	sqfs_tree_node_t *it;
+
+	while (root->children != NULL) {
+		it = root->children;
+		root->children = it->next;
+
+		sqfs_dir_tree_destroy(it);
+	}
+
+	free(root->inode);
+	free(root);
+}
+
+int sqfs_dir_reader_get_full_hierarchy(sqfs_dir_reader_t *rd,
+				       const sqfs_id_table_t *idtbl,
+				       const char *path, unsigned int flags,
+				       sqfs_tree_node_t **out)
+{
+	sqfs_tree_node_t *root, *tail, *new;
+	sqfs_inode_generic_t *inode;
+	sqfs_dir_entry_t *ent;
+	const char *ptr;
+	int ret;
+
+	ret = sqfs_dir_reader_get_root_inode(rd, &inode);
+	if (ret)
+		return ret;
+
+	root = tail = create_node(inode, "");
+	if (root == NULL) {
+		free(inode);
+		return SQFS_ERROR_ALLOC;
+	}
+	inode = NULL;
+
+	while (path != NULL && *path != '\0') {
+		if (*path == '/' || *path == '\\') {
+			while (*path == '/' || *path == '\\')
+				++path;
+			continue;
+		}
+
+		ret = sqfs_dir_reader_open_dir(rd, tail->inode);
+		if (ret)
+			goto fail;
+
+		ptr = strchr(path, '/');
+		if (ptr == NULL)
+			ptr = strchrnul(path, '\\');
+
+		for (;;) {
+			ret = sqfs_dir_reader_read(rd, &ent);
+			if (ret < 0)
+				goto fail;
+			if (ret > 0) {
+				ret = SQFS_ERROR_NO_ENTRY;
+				goto fail;
+			}
+
+			ret = strncmp((const char *)ent->name,
+				      path, ptr - path);
+			if (ret == 0 && ent->name[ptr - path] == '\0')
+				break;
+			free(ent);
+		}
+
+		ret = sqfs_dir_reader_get_inode(rd, &inode);
+		if (ret) {
+			free(ent);
+			goto fail;
+		}
+
+		new = create_node(inode, (const char *)ent->name);
+		free(ent);
+
+		if (new == NULL) {
+			free(inode);
+			ret = SQFS_ERROR_ALLOC;
+			goto fail;
+		}
+
+		inode = NULL;
+		path = ptr;
+
+		if (flags & SQFS_TREE_STORE_PARENTS) {
+			tail->children = new;
+			new->parent = tail;
+			tail = new;
+		} else {
+			sqfs_dir_tree_destroy(root);
+			root = tail = new;
+		}
+	}
+
+	if (tail->inode->base.type == SQFS_INODE_DIR ||
+	    tail->inode->base.type == SQFS_INODE_EXT_DIR) {
+		ret = sqfs_dir_reader_open_dir(rd, tail->inode);
+		if (ret)
+			goto fail;
+
+		ret = fill_dir(rd, tail, flags);
+		if (ret)
+			goto fail;
+	}
+
+	ret = resolve_ids(root, idtbl);
+	if (ret)
+		goto fail;
+
+	*out = root;
+	return 0;
+fail:
+	sqfs_dir_tree_destroy(root);
+	return ret;
+}