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/*
* Functions to manage the superblock of the filesystem. These functions are
* are called at the beginning and at the end of the server.
*/
#include "inc.h"
#include <string.h>
#include <minix/com.h>
#include <minix/u64.h>
#include <minix/bdev.h>
int release_vol_pri_desc(struct iso9660_vol_pri_desc *vol_pri)
{
/* Release the root dir root. */
if (vol_pri->i_count > 0) {
put_inode(vol_pri->inode_root);
vol_pri->inode_root = NULL;
vol_pri->i_count = 0;
}
return OK;
}
static int create_vol_pri_desc(struct iso9660_vol_pri_desc *vol_pri, char *buf)
{
/*
* This function fullfill the super block data structure using the
* information contained in the buffer.
*/
struct iso9660_dir_record *root_record;
struct inode_dir_entry dir_entry;
struct dir_extent extent;
size_t dummy_offset = 0;
if (vol_pri->i_count > 0)
release_vol_pri_desc(vol_pri);
memcpy(vol_pri, buf, 2048);
/* Check various fields for consistency. */
if ((memcmp(vol_pri->standard_id, "CD001",
ISO9660_SIZE_STANDARD_ID) != 0)
|| (vol_pri->vd_version != 1)
|| (vol_pri->logical_block_size_l < 2048))
return EINVAL;
lmfs_set_blocksize(vol_pri->logical_block_size_l);
lmfs_set_blockusage(vol_pri->volume_space_size_l,
vol_pri->volume_space_size_l);
/* Read root directory record. */
root_record = (struct iso9660_dir_record *)vol_pri->root_directory;
extent.location =
root_record->loc_extent_l + root_record->ext_attr_rec_length;
extent.length =
root_record->data_length_l / vol_pri->logical_block_size_l;
extent.next = NULL;
if (root_record->data_length_l % vol_pri->logical_block_size_l)
extent.length++;
if (read_inode(&dir_entry, &extent, &dummy_offset) != OK) {
return EINVAL;
}
dir_entry.i_node->i_count = 1;
vol_pri->inode_root = dir_entry.i_node;
vol_pri->i_count = 1;
return OK;
}
int read_vds(struct iso9660_vol_pri_desc *vol_pri, dev_t dev)
{
/*
* This function reads from a ISO9660 filesystem (in the device dev)
* the super block and saves it in vol_pri.
*/
size_t offset;
int vol_ok = FALSE, vol_pri_flag = FALSE;
int r;
static char sbbuf[ISO9660_MIN_BLOCK_SIZE];
int i = 0;
for(offset = ISO9660_SUPER_BLOCK_POSITION;
!vol_ok && i++ < MAX_ATTEMPTS;
offset += ISO9660_MIN_BLOCK_SIZE) {
/* Read the sector of the super block. */
r = bdev_read(dev, offset, sbbuf, ISO9660_MIN_BLOCK_SIZE,
BDEV_NOFLAGS);
if (r != ISO9660_MIN_BLOCK_SIZE) {
/* Damaged sector or what? */
return EINVAL;
}
if ((sbbuf[0] & BYTE) == VD_PRIMARY) {
/* Free already parsed descriptor, if any. */
if (vol_pri_flag == TRUE) {
release_vol_pri_desc(vol_pri);
vol_pri_flag = FALSE;
}
/* Copy the buffer in the data structure. */
if (create_vol_pri_desc(vol_pri, sbbuf) == OK) {
vol_pri_flag = TRUE;
}
}
if ((sbbuf[0] & BYTE) == VD_SET_TERM) {
/* I dont need to save anything about it */
vol_ok = TRUE;
}
}
if (vol_ok == FALSE || vol_pri_flag == FALSE)
return EINVAL; /* If no superblock was found... */
else
return OK; /* otherwise. */
}
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