fs/isofs/rock.c

Source file repositories/reference/linux-study-clean/fs/isofs/rock.c

File Facts

System
Linux kernel
Corpus path
fs/isofs/rock.c
Extension
.c
Size
19858 bytes
Lines
831
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

struct rock_state {
	void *buffer;
	unsigned char *chr;
	int len;
	int cont_size;
	int cont_extent;
	int cont_offset;
	int cont_loops;
	struct inode *inode;
};

/*
 * This is a way of ensuring that we have something in the system
 * use fields that is compatible with Rock Ridge.  Return zero on success.
 */

static int check_sp(struct rock_ridge *rr, struct inode *inode)
{
	if (rr->u.SP.magic[0] != 0xbe)
		return -1;
	if (rr->u.SP.magic[1] != 0xef)
		return -1;
	ISOFS_SB(inode->i_sb)->s_rock_offset = rr->u.SP.skip;
	return 0;
}

static void setup_rock_ridge(struct iso_directory_record *de,
			struct inode *inode, struct rock_state *rs)
{
	rs->len = sizeof(struct iso_directory_record) + de->name_len[0];
	if (rs->len & 1)
		(rs->len)++;
	rs->chr = (unsigned char *)de + rs->len;
	rs->len = *((unsigned char *)de) - rs->len;
	if (rs->len < 0)
		rs->len = 0;

	if (ISOFS_SB(inode->i_sb)->s_rock_offset != -1) {
		rs->len -= ISOFS_SB(inode->i_sb)->s_rock_offset;
		rs->chr += ISOFS_SB(inode->i_sb)->s_rock_offset;
		if (rs->len < 0)
			rs->len = 0;
	}
}

static void init_rock_state(struct rock_state *rs, struct inode *inode)
{
	memset(rs, 0, sizeof(*rs));
	rs->inode = inode;
}

/* Maximum number of Rock Ridge continuation entries */
#define RR_MAX_CE_ENTRIES 32

/*
 * Returns 0 if the caller should continue scanning, 1 if the scan must end
 * and -ve on error.
 */
static int rock_continue(struct rock_state *rs)
{
	int ret = 1;
	int blocksize = 1 << rs->inode->i_blkbits;
	const int min_de_size = offsetof(struct rock_ridge, u);

	kfree(rs->buffer);
	rs->buffer = NULL;

	if ((unsigned)rs->cont_offset > blocksize - min_de_size ||
	    (unsigned)rs->cont_size > blocksize ||
	    (unsigned)(rs->cont_offset + rs->cont_size) > blocksize) {
		printk(KERN_NOTICE "rock: corrupted directory entry. "
			"extent=%d, offset=%d, size=%d\n",
			rs->cont_extent, rs->cont_offset, rs->cont_size);
		ret = -EIO;
		goto out;
	}

	if ((unsigned)rs->cont_extent >= ISOFS_SB(rs->inode->i_sb)->s_nzones) {
		printk(KERN_NOTICE "rock: corrupted directory entry. "
			"extent=%u out of volume (nzones=%lu)\n",
			(unsigned)rs->cont_extent,
			ISOFS_SB(rs->inode->i_sb)->s_nzones);
		ret = -EIO;
		goto out;
	}

	if (rs->cont_extent) {
		struct buffer_head *bh;

		rs->buffer = kmalloc(rs->cont_size, GFP_KERNEL);

Annotation

Implementation Notes