linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 *  linux/fs/isofs/rock.c

 *

 *  (C) 1992, 1993  Eric Youngdale

 *

 *  Rock Ridge Extensions to iso9660

 */

​

#include <linux/slab.h>

#include <linux/pagemap.h>

​

#include "isofs.h"

#include "rock.h"

​

/*

 * These functions are designed to read the system areas of a directory record

 * and extract relevant information.  There are different functions provided

 * depending upon what information we need at the time.  One function fills

 * out an inode structure, a second one extracts a filename, a third one

 * returns a symbolic link name, and a fourth one returns the extent number

 * for the file.

 */

​

#define SIG(A,B) ((A) | ((B) << 8)) /* isonum_721() */

​

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;