Changeset 9b9d37bb in mainline for uspace/lib/ext4/libext4_directory.c

Timestamp:

2011-10-06T09:48:53Z (14 years ago)

Author:

Frantisek Princ <frantisek.princ@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

1114173

Parents:

3712434

Message:

mounting + list of mounted directory (ported from ext2) - many TODO remaining

File:

• uspace/lib/ext4/libext4_directory.c (modified) (1 diff)

uspace/lib/ext4/libext4_directory.c

@@ -36 +36 @@
  */
 
+#include <byteorder.h>
+#include <errno.h>
 #include "libext4.h"
+
+static int ext4_directory_iterator_set(ext4_directory_iterator_t *,
+    uint32_t);
+
+
+uint32_t ext4_directory_entry_ll_get_inode(ext4_directory_entry_ll_t *de)
+{
+        return uint32_t_le2host(de->inode);
+}
+
+uint16_t ext4_directory_entry_ll_get_entry_length(
+    ext4_directory_entry_ll_t *de)
+{
+        return uint16_t_le2host(de->entry_length);
+}
+
+uint16_t ext4_directory_entry_ll_get_name_length(
+    ext4_superblock_t *sb, ext4_directory_entry_ll_t *de)
+{
+        if (ext4_superblock_get_rev_level(sb) == 0 &&
+            ext4_superblock_get_minor_rev_level(sb) < 5) {
+                return ((uint16_t)de->name_length_high) << 8 |
+                    ((uint16_t)de->name_length);
+        }
+        return de->name_length;
+}
+
+int ext4_directory_iterator_init(ext4_directory_iterator_t *it,
+    ext4_filesystem_t *fs, ext4_inode_ref_t *inode_ref, aoff64_t pos)
+{
+        it->inode_ref = inode_ref;
+        it->fs = fs;
+        it->current = NULL;
+        it->current_offset = 0;
+        it->current_block = NULL;
+
+        return ext4_directory_iterator_seek(it, pos);
+}
+
+
+int ext4_directory_iterator_next(ext4_directory_iterator_t *it)
+{
+        uint16_t skip;
+
+        assert(it->current != NULL);
+
+        skip = ext4_directory_entry_ll_get_entry_length(it->current);
+
+        return ext4_directory_iterator_seek(it, it->current_offset + skip);
+}
+
+
+int ext4_directory_iterator_seek(ext4_directory_iterator_t *it, aoff64_t pos)
+{
+        int rc;
+
+        uint64_t size;
+        aoff64_t current_block_idx;
+        aoff64_t next_block_idx;
+        uint32_t next_block_phys_idx;
+        uint32_t block_size;
+
+        size = ext4_inode_get_size(it->fs->superblock, it->inode_ref->inode);
+
+        /* The iterator is not valid until we seek to the desired position */
+        it->current = NULL;
+
+        /* Are we at the end? */
+        if (pos >= size) {
+                if (it->current_block) {
+                        rc = block_put(it->current_block);
+                        it->current_block = NULL;
+                        if (rc != EOK) {
+                                return rc;
+                        }
+                }
+
+                it->current_offset = pos;
+                return EOK;
+        }
+
+        block_size = ext4_superblock_get_block_size(it->fs->superblock);
+        current_block_idx = it->current_offset / block_size;
+        next_block_idx = pos / block_size;
+
+        /* If we don't have a block or are moving accross block boundary,
+         * we need to get another block
+         */
+        if (it->current_block == NULL || current_block_idx != next_block_idx) {
+                if (it->current_block) {
+                        rc = block_put(it->current_block);
+                        it->current_block = NULL;
+                        if (rc != EOK) {
+                                return rc;
+                        }
+                }
+
+                rc = ext4_filesystem_get_inode_data_block_index(it->fs,
+                    it->inode_ref->inode, next_block_idx, &next_block_phys_idx);
+                if (rc != EOK) {
+                        return rc;
+                }
+
+                rc = block_get(&it->current_block, it->fs->device, next_block_phys_idx,
+                    BLOCK_FLAGS_NONE);
+                if (rc != EOK) {
+                        it->current_block = NULL;
+                        return rc;
+                }
+        }
+
+        it->current_offset = pos;
+        return ext4_directory_iterator_set(it, block_size);
+}
+
+static int ext4_directory_iterator_set(ext4_directory_iterator_t *it,
+    uint32_t block_size)
+{
+        uint32_t offset_in_block = it->current_offset % block_size;
+
+        it->current = NULL;
+
+        /* Ensure proper alignment */
+        if ((offset_in_block % 4) != 0) {
+                return EIO;
+        }
+
+        /* Ensure that the core of the entry does not overflow the block */
+        if (offset_in_block > block_size - 8) {
+                return EIO;
+        }
+
+        ext4_directory_entry_ll_t *entry = it->current_block->data + offset_in_block;
+
+        /* Ensure that the whole entry does not overflow the block */
+        uint16_t length = ext4_directory_entry_ll_get_entry_length(entry);
+        if (offset_in_block + length > block_size) {
+                return EIO;
+        }
+
+        /* Ensure the name length is not too large */
+        if (ext4_directory_entry_ll_get_name_length(it->fs->superblock,
+            entry) > length-8) {
+                return EIO;
+        }
+
+        it->current = entry;
+        return EOK;
+}
+
+
+int ext4_directory_iterator_fini(ext4_directory_iterator_t *it)
+{
+        int rc;
+
+        it->fs = NULL;
+        it->inode_ref = NULL;
+        it->current = NULL;
+
+        if (it->current_block) {
+                rc = block_put(it->current_block);
+                if (rc != EOK) {
+                        return rc;
+                }
+        }
+
+        return EOK;
+}