1 files changed, 304 insertions, 0 deletions
diff --git a/lib/exfat_fs.c b/lib/exfat_fs.c
new file mode 100644
index 0000000..d563c61
--- /dev/null
+++ b/lib/exfat_fs.c
@@ -0,0 +1,304 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   Copyright (C) 2021 LG Electronics.
+ *
+ *   Author(s): Hyunchul Lee <hyc.lee@gmail.com>
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+
+#include "exfat_ondisk.h"
+#include "libexfat.h"
+
+#include "exfat_fs.h"
+#include "exfat_dir.h"
+
+struct exfat_inode *exfat_alloc_inode(__u16 attr)
+{
+	struct exfat_inode *node;
+	int size;
+
+	size = offsetof(struct exfat_inode, name) + NAME_BUFFER_SIZE;
+	node = (struct exfat_inode *)calloc(1, size);
+	if (!node) {
+		exfat_err("failed to allocate exfat_node\n");
+		return NULL;
+	}
+
+	node->parent = NULL;
+	INIT_LIST_HEAD(&node->children);
+	INIT_LIST_HEAD(&node->sibling);
+	INIT_LIST_HEAD(&node->list);
+
+	node->attr = attr;
+	return node;
+}
+
+void exfat_free_inode(struct exfat_inode *node)
+{
+	if (node) {
+		if (node->dentry_set)
+			free(node->dentry_set);
+		free(node);
+	}
+}
+
+void exfat_free_children(struct exfat_inode *dir, bool file_only)
+{
+	struct exfat_inode *node, *i;
+
+	list_for_each_entry_safe(node, i, &dir->children, sibling) {
+		if (file_only) {
+			if (!(node->attr & ATTR_SUBDIR)) {
+				list_del(&node->sibling);
+				exfat_free_inode(node);
+			}
+		} else {
+			list_del(&node->sibling);
+			list_del(&node->list);
+			exfat_free_inode(node);
+		}
+	}
+}
+
+void exfat_free_file_children(struct exfat_inode *dir)
+{
+	exfat_free_children(dir, true);
+}
+
+/* delete @child and all ancestors that does not have
+ * children
+ */
+void exfat_free_ancestors(struct exfat_inode *child)
+{
+	struct exfat_inode *parent;
+
+	while (child && list_empty(&child->children)) {
+		if (!child->parent || !(child->attr & ATTR_SUBDIR))
+			return;
+
+		parent = child->parent;
+		list_del(&child->sibling);
+		exfat_free_inode(child);
+
+		child = parent;
+	}
+	return;
+}
+
+void exfat_free_dir_list(struct exfat *exfat)
+{
+	struct exfat_inode *dir, *i;
+
+	list_for_each_entry_safe(dir, i, &exfat->dir_list, list) {
+		if (!dir->parent)
+			continue;
+		exfat_free_file_children(dir);
+		list_del(&dir->list);
+		exfat_free_inode(dir);
+	}
+}
+
+void exfat_free_exfat(struct exfat *exfat)
+{
+	if (exfat) {
+		if (exfat->bs)
+			free(exfat->bs);
+		if (exfat->alloc_bitmap)
+			free(exfat->alloc_bitmap);
+		if (exfat->disk_bitmap)
+			free(exfat->disk_bitmap);
+		if (exfat->ohead_bitmap)
+			free(exfat->ohead_bitmap);
+		if (exfat->upcase_table)
+			free(exfat->upcase_table);
+		if (exfat->root)
+			exfat_free_inode(exfat->root);
+		if (exfat->zero_cluster)
+			free(exfat->zero_cluster);
+		free(exfat);
+	}
+}
+
+struct exfat *exfat_alloc_exfat(struct exfat_blk_dev *blk_dev, struct pbr *bs)
+{
+	struct exfat *exfat;
+
+	exfat = (struct exfat *)calloc(1, sizeof(*exfat));
+	if (!exfat)
+		return NULL;
+
+	INIT_LIST_HEAD(&exfat->dir_list);
+	exfat->blk_dev = blk_dev;
+	exfat->bs = bs;
+	exfat->clus_count = le32_to_cpu(bs->bsx.clu_count);
+	exfat->clus_size = EXFAT_CLUSTER_SIZE(bs);
+	exfat->sect_size = EXFAT_SECTOR_SIZE(bs);
+
+	/* TODO: bitmap could be very large. */
+	exfat->alloc_bitmap = (char *)calloc(1,
+			EXFAT_BITMAP_SIZE(exfat->clus_count));
+	if (!exfat->alloc_bitmap) {
+		exfat_err("failed to allocate bitmap\n");
+		goto err;
+	}
+
+	exfat->ohead_bitmap =
+		calloc(1, EXFAT_BITMAP_SIZE(exfat->clus_count));
+	if (!exfat->ohead_bitmap) {
+		exfat_err("failed to allocate bitmap\n");
+		goto err;
+	}
+
+	exfat->disk_bitmap =
+		calloc(1, EXFAT_BITMAP_SIZE(exfat->clus_count));
+	if (!exfat->disk_bitmap) {
+		exfat_err("failed to allocate bitmap\n");
+		goto err;
+	}
+
+	exfat->zero_cluster = calloc(1, exfat->clus_size);
+	if (!exfat->zero_cluster) {
+		exfat_err("failed to allocate a zero-filled cluster buffer\n");
+		goto err;
+	}
+
+	exfat->start_clu = EXFAT_FIRST_CLUSTER;
+	return exfat;
+err:
+	exfat_free_exfat(exfat);
+	return NULL;
+}
+
+struct buffer_desc *exfat_alloc_buffer(int count,
+				       unsigned int clu_size, unsigned int sect_size)
+{
+	struct buffer_desc *bd;
+	int i;
+
+	bd = (struct buffer_desc *)calloc(sizeof(*bd), count);
+	if (!bd)
+		return NULL;
+
+	for (i = 0; i < count; i++) {
+		bd[i].buffer = (char *)malloc(clu_size);
+		if (!bd[i].buffer)
+			goto err;
+		bd[i].dirty = (char *)calloc(clu_size / sect_size, 1);
+		if (!bd[i].dirty)
+			goto err;
+	}
+	return bd;
+err:
+	exfat_free_buffer(bd, count);
+	return NULL;
+}
+
+void exfat_free_buffer(struct buffer_desc *bd, int count)
+{
+	int i;
+
+	for (i = 0; i < count; i++) {
+		if (bd[i].buffer)
+			free(bd[i].buffer);
+		if (bd[i].dirty)
+			free(bd[i].dirty);
+	}
+	free(bd);
+}
+
+/*
+ * get references of ancestors that include @child until the count of
+ * ancesters is not larger than @count and the count of characters of
+ * their names is not larger than @max_char_len.
+ * return true if root is reached.
+ */
+static bool get_ancestors(struct exfat_inode *child,
+			  struct exfat_inode **ancestors, int count,
+			  int max_char_len,
+			  int *ancestor_count)
+{
+	struct exfat_inode *dir;
+	int name_len, char_len;
+	int root_depth, depth, i;
+
+	root_depth = 0;
+	char_len = 0;
+	max_char_len += 1;
+
+	dir = child;
+	while (dir) {
+		name_len = exfat_utf16_len(dir->name, NAME_BUFFER_SIZE);
+		if (char_len + name_len > max_char_len)
+			break;
+
+		/* include '/' */
+		char_len += name_len + 1;
+		root_depth++;
+
+		dir = dir->parent;
+	}
+
+	depth = MIN(root_depth, count);
+
+	for (dir = child, i = depth - 1; i >= 0; dir = dir->parent, i--)
+		ancestors[i] = dir;
+
+	*ancestor_count = depth;
+	return !dir;
+}
+
+int exfat_resolve_path(struct path_resolve_ctx *ctx, struct exfat_inode *child)
+{
+	int depth, i;
+	int name_len;
+	__le16 *utf16_path;
+	static const __le16 utf16_slash = cpu_to_le16(0x002F);
+	static const __le16 utf16_null = cpu_to_le16(0x0000);
+	size_t in_size;
+
+	ctx->local_path[0] = '\0';
+
+	get_ancestors(child,
+		      ctx->ancestors,
+		      sizeof(ctx->ancestors) / sizeof(ctx->ancestors[0]),
+		      PATH_MAX,
+		      &depth);
+
+	utf16_path = ctx->utf16_path;
+	for (i = 0; i < depth; i++) {
+		name_len = exfat_utf16_len(ctx->ancestors[i]->name,
+					   NAME_BUFFER_SIZE);
+		memcpy((char *)utf16_path, (char *)ctx->ancestors[i]->name,
+		       name_len * 2);
+		utf16_path += name_len;
+		memcpy((char *)utf16_path, &utf16_slash, sizeof(utf16_slash));
+		utf16_path++;
+	}
+
+	if (depth > 1)
+		utf16_path--;
+	memcpy((char *)utf16_path, &utf16_null, sizeof(utf16_null));
+	utf16_path++;
+
+	in_size = (utf16_path - ctx->utf16_path) * sizeof(__le16);
+	return exfat_utf16_dec(ctx->utf16_path, in_size,
+				ctx->local_path, sizeof(ctx->local_path));
+}
+
+int exfat_resolve_path_parent(struct path_resolve_ctx *ctx,
+			      struct exfat_inode *parent, struct exfat_inode *child)
+{
+	int ret;
+	struct exfat_inode *old;
+
+	old = child->parent;
+	child->parent = parent;
+
+	ret = exfat_resolve_path(ctx, child);
+	child->parent = old;
+	return ret;
+}