unsquashfs: add function to turn inode into fs tree node

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

1 files changed, 144 insertions, 0 deletions

diff --git a/unpack/tree_node_from_inode.c b/unpack/tree_node_from_inode.c
new file mode 100644
index 0000000..95056a7
--- /dev/null
+++ b/unpack/tree_node_from_inode.c
@@ -0,0 +1,144 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#include "unsquashfs.h"
+
+static size_t compute_size(sqfs_inode_generic_t *inode, const char *name,
+			   size_t block_size)
+{
+	size_t size = sizeof(tree_node_t) + strlen(name) + 1;
+	size_t block_count = 0;
+
+	switch (inode->base.type) {
+	case SQFS_INODE_DIR:
+	case SQFS_INODE_EXT_DIR:
+		size += sizeof(dir_info_t);
+		break;
+	case SQFS_INODE_FILE:
+		size += sizeof(file_info_t);
+		block_count = inode->data.file.file_size / block_size;
+		break;
+	case SQFS_INODE_EXT_FILE:
+		size += sizeof(file_info_t);
+		block_count = inode->data.file_ext.file_size / block_size;
+		break;
+	case SQFS_INODE_SLINK:
+	case SQFS_INODE_EXT_SLINK:
+		size += strlen(inode->slink_target) + 1;
+		break;
+	default:
+		break;
+	}
+
+	return size + block_count * sizeof(uint32_t);
+}
+
+static void copy_block_sizes(sqfs_inode_generic_t *inode, tree_node_t *out,
+			     size_t block_size)
+{
+	size_t block_count = out->data.file->size / block_size;
+
+	out->name += block_count * sizeof(uint32_t);
+
+	if (block_count) {
+		memcpy(out->data.file->blocksizes, inode->block_sizes,
+		       block_count * sizeof(uint32_t));
+	}
+}
+
+tree_node_t *tree_node_from_inode(sqfs_inode_generic_t *inode,
+				  const id_table_t *idtbl,
+				  const char *name,
+				  size_t block_size)
+{
+	tree_node_t *out;
+
+	if (inode->base.uid_idx >= idtbl->num_ids) {
+		fputs("converting inode to fs tree node: UID out of range\n",
+		      stderr);
+		return NULL;
+	}
+
+	if (inode->base.gid_idx >= idtbl->num_ids) {
+		fputs("converting inode to fs tree node: GID out of range\n",
+		      stderr);
+		return NULL;
+	}
+
+	out = calloc(1, compute_size(inode, name, block_size));
+	if (out == NULL) {
+		perror("converting inode to fs tree node");
+		return NULL;
+	}
+
+	out->uid = idtbl->ids[inode->base.uid_idx];
+	out->gid = idtbl->ids[inode->base.gid_idx];
+	out->mode = inode->base.mode;
+	out->type = inode->base.type;
+	out->inode_num = inode->base.inode_number;
+	out->name = (char *)out->payload;
+
+	switch (inode->base.type) {
+	case SQFS_INODE_DIR:
+		out->data.dir = (dir_info_t *)out->payload;
+		out->name += sizeof(dir_info_t);
+
+		out->data.dir->size = inode->data.dir.size;
+		out->data.dir->start_block = inode->data.dir.start_block;
+		out->data.dir->block_offset = inode->data.dir.offset;
+		break;
+	case SQFS_INODE_EXT_DIR:
+		out->data.dir = (dir_info_t *)out->payload;
+		out->name += sizeof(dir_info_t);
+
+		out->data.dir->size = inode->data.dir_ext.size;
+		out->data.dir->start_block = inode->data.dir_ext.start_block;
+		out->data.dir->block_offset = inode->data.dir_ext.offset;
+		break;
+	case SQFS_INODE_FILE:
+		out->data.file = (file_info_t *)out->payload;
+		out->name += sizeof(file_info_t);
+
+		out->data.file->size = inode->data.file.file_size;
+		out->data.file->startblock = inode->data.file.blocks_start;
+		out->data.file->fragment = inode->data.file.fragment_index;
+		out->data.file->fragment_offset =
+			inode->data.file.fragment_offset;
+
+		copy_block_sizes(inode, out, block_size);
+		break;
+	case SQFS_INODE_EXT_FILE:
+		out->data.file = (file_info_t *)out->payload;
+		out->name += sizeof(file_info_t);
+
+		out->data.file->size = inode->data.file_ext.file_size;
+		out->data.file->startblock = inode->data.file_ext.blocks_start;
+		out->data.file->fragment = inode->data.file_ext.fragment_idx;
+		out->data.file->fragment_offset =
+			inode->data.file_ext.fragment_offset;
+
+		copy_block_sizes(inode, out, block_size);
+		break;
+	case SQFS_INODE_SLINK:
+	case SQFS_INODE_EXT_SLINK:
+		out->data.slink_target = (char *)out->payload;
+		strcpy(out->data.slink_target, inode->slink_target);
+
+		out->name = (char *)out->payload +
+			strlen(inode->slink_target) + 1;
+		break;
+	case SQFS_INODE_BDEV:
+	case SQFS_INODE_CDEV:
+		out->name = (char *)out->payload;
+		out->data.devno = inode->data.dev.devno;
+		break;
+	case SQFS_INODE_EXT_BDEV:
+	case SQFS_INODE_EXT_CDEV:
+		out->name = (char *)out->payload;
+		out->data.devno = inode->data.dev_ext.devno;
+		break;
+	default:
+		break;
+	}
+
+	strcpy(out->name, name);
+	return out;
+}