fs/squashfs/xattr.c

Source file repositories/reference/linux-study-clean/fs/squashfs/xattr.c

File Facts

System
Linux kernel
Corpus path
fs/squashfs/xattr.c
Extension
.c
Size
6869 bytes
Lines
272
Domain
Core OS
Bucket
VFS And Filesystem Core
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

if (handler && (!handler->list || handler->list(d))) {
			const char *prefix = handler->prefix ?: handler->name;
			size_t prefix_size = strlen(prefix);

			if (buffer) {
				if (prefix_size + name_size + 1 > rest) {
					err = -ERANGE;
					goto failed;
				}
				memcpy(buffer, prefix, prefix_size);
				buffer += prefix_size;
			}
			err = squashfs_read_metadata(sb, buffer, &start,
				&offset, name_size);
			if (err < 0)
				goto failed;
			if (buffer) {
				buffer[name_size] = '\0';
				buffer += name_size + 1;
			}
			rest -= prefix_size + name_size + 1;
		} else  {
			/* no handler or insuffficient privileges, so skip */
			err = squashfs_read_metadata(sb, NULL, &start,
				&offset, name_size);
			if (err < 0)
				goto failed;
		}


		/* skip remaining xattr entry */
		err = squashfs_read_metadata(sb, &val, &start, &offset,
						sizeof(val));
		if (err < 0)
			goto failed;

		err = squashfs_read_metadata(sb, NULL, &start, &offset,
						le32_to_cpu(val.vsize));
		if (err < 0)
			goto failed;
	}
	err = buffer_size - rest;

failed:
	return err;
}


static int squashfs_xattr_get(struct inode *inode, int name_index,
	const char *name, void *buffer, size_t buffer_size)
{
	struct super_block *sb = inode->i_sb;
	struct squashfs_sb_info *msblk = sb->s_fs_info;
	u64 start = SQUASHFS_XATTR_BLK(squashfs_i(inode)->xattr)
						 + msblk->xattr_table;
	int offset = SQUASHFS_XATTR_OFFSET(squashfs_i(inode)->xattr);
	int count = squashfs_i(inode)->xattr_count;
	int name_len = strlen(name);
	int err, vsize;
	char *target = kmalloc(name_len, GFP_KERNEL);

	if (target == NULL)
		return  -ENOMEM;

	/* loop reading each xattr name */
	for (; count; count--) {
		struct squashfs_xattr_entry entry;
		struct squashfs_xattr_val val;
		int type, prefix, name_size;

		err = squashfs_read_metadata(sb, &entry, &start, &offset,
							sizeof(entry));
		if (err < 0)
			goto failed;

		name_size = le16_to_cpu(entry.size);
		type = le16_to_cpu(entry.type);
		prefix = type & SQUASHFS_XATTR_PREFIX_MASK;

		if (prefix == name_index && name_size == name_len)
			err = squashfs_read_metadata(sb, target, &start,
						&offset, name_size);
		else
			err = squashfs_read_metadata(sb, NULL, &start,
						&offset, name_size);
		if (err < 0)
			goto failed;

		if (prefix == name_index && name_size == name_len &&
					strncmp(target, name, name_size) == 0) {

Annotation

Implementation Notes