/* msdos_find_node_by_cluster_num_in_fat_file --
* Find node with specified number of cluster in fat-file.
*
* PARAMETERS:
* mt_entry - mount table entry
* fat_fd - fat-file descriptor
* cl4find - number of cluster to find
* paux - identify a node location on the disk -
* cluster num and offset inside the cluster
* dir_entry - placeholder for found node
*
* RETURNS:
* RC_OK on success, or error code if error occured
*
*/
int msdos_find_node_by_cluster_num_in_fat_file(
rtems_filesystem_mount_table_entry_t *mt_entry,
fat_file_fd_t *fat_fd,
uint32_t cl4find,
fat_auxiliary_t *paux,
char *dir_entry
)
{
int rc = RC_OK;
ssize_t ret = 0;
msdos_fs_info_t *fs_info = mt_entry->fs_info;
uint32_t bts2rd = 0;
uint32_t i = 0, j = 0;
if (FAT_FD_OF_ROOT_DIR(fat_fd) &&
(fs_info->fat.vol.type & (FAT_FAT12 | FAT_FAT16)))
bts2rd = fat_fd->fat_file_size;
else
bts2rd = fs_info->fat.vol.bpc;
while ((ret = fat_file_read(mt_entry, fat_fd, j * bts2rd, bts2rd,
fs_info->cl_buf)) != FAT_EOF)
{
if ( ret < MSDOS_DIRECTORY_ENTRY_STRUCT_SIZE )
set_errno_and_return_minus_one( EIO );
assert(ret == bts2rd);
for (i = 0; i < bts2rd; i += MSDOS_DIRECTORY_ENTRY_STRUCT_SIZE)
{
/* if this and all rest entries are empty - return not-found */
if ((*MSDOS_DIR_NAME(fs_info->cl_buf + i)) ==
MSDOS_THIS_DIR_ENTRY_AND_REST_EMPTY)
return MSDOS_NAME_NOT_FOUND_ERR;
/* have to look at the DIR_NAME as "raw" 8-bit data */
/* if this entry is empty - skip it */
if ((*(uint8_t *)MSDOS_DIR_NAME(fs_info->cl_buf + i)) ==
MSDOS_THIS_DIR_ENTRY_EMPTY)
continue;
/* if get a non-empty entry - compare clusters num */
if (MSDOS_EXTRACT_CLUSTER_NUM((fs_info->cl_buf + i)) == cl4find)
{
/* on success fill aux structure and copy all 32 bytes */
rc = fat_file_ioctl(mt_entry, fat_fd, F_CLU_NUM, j * bts2rd,
&paux->cln);
if (rc != RC_OK)
return rc;
paux->ofs = i;
memcpy(dir_entry, fs_info->cl_buf + i,
MSDOS_DIRECTORY_ENTRY_STRUCT_SIZE);
return RC_OK;
}
}
j++;
}
return MSDOS_NAME_NOT_FOUND_ERR;
}
/* fat_file_read --
* Read 'count' bytes from 'start' position from fat-file. This
* interface hides the architecture of fat-file, represents it as
* linear file
*
* PARAMETERS:
* mt_entry - mount table entry
* fat_fd - fat-file descriptor
* start - offset in fat-file (in bytes) to read from
* count - count of bytes to read
* buf - buffer provided by user
*
* RETURNS:
* the number of bytes read on success, or -1 if error occured (errno
* set appropriately)
*/
ssize_t
fat_file_read(
rtems_filesystem_mount_table_entry_t *mt_entry,
fat_file_fd_t *fat_fd,
uint32_t start,
uint32_t count,
uint8_t *buf
)
{
int rc = RC_OK;
ssize_t ret = 0;
fat_fs_info_t *fs_info = mt_entry->fs_info;
uint32_t cmpltd = 0;
uint32_t cur_cln = 0;
uint32_t cl_start = 0;
uint32_t save_cln = 0;
uint32_t ofs = 0;
uint32_t save_ofs;
uint32_t sec = 0;
uint32_t byte = 0;
uint32_t c = 0;
/* it couldn't be removed - otherwise cache update will be broken */
if (count == 0)
return cmpltd;
/*
* >= because start is offset and computed from 0 and file_size
* computed from 1
*/
if ( start >= fat_fd->fat_file_size )
return FAT_EOF;
if ((count > fat_fd->fat_file_size) ||
(start > fat_fd->fat_file_size - count))
count = fat_fd->fat_file_size - start;
if ((FAT_FD_OF_ROOT_DIR(fat_fd)) &&
(fs_info->vol.type & (FAT_FAT12 | FAT_FAT16)))
{
sec = fat_cluster_num_to_sector_num(mt_entry, fat_fd->cln);
sec += (start >> fs_info->vol.sec_log2);
byte = start & (fs_info->vol.bps - 1);
ret = _fat_block_read(mt_entry, sec, byte, count, buf);
if ( ret < 0 )
return -1;
return ret;
}
/* msdos_find_name_in_fat_file --
* This routine is used in two ways: for a new mode creation (a) or for
* search the node which correspondes to the 'name' parameter (b).
* In case (a) name should be set up to NULL and 'name_dir_entry' should
* point to initialized 32 bytes structure described a new node.
* In case (b) 'name' should contain a valid string.
*
* (a): reading fat-file corresponded to directory we are going to create
* node in. If found free slot write contents of name_dir_entry into
* it.
*
* (b): reading fat-file corresponded to directory and trying to find slot
* with the name field == name parameter
*
* PARAMETERS:
* mt_entry - mount table entry
* fat_fd - fat-file descriptor
* name - NULL or name to find
* paux - identify a node location on the disk -
* number of cluster and offset inside the cluster
* name_dir_entry - node to create/placeholder for found node
*
* RETURNS:
* RC_OK on success, or error code if error occured (errno set
* appropriately)
*
*/
int msdos_find_name_in_fat_file(
rtems_filesystem_mount_table_entry_t *mt_entry,
fat_file_fd_t *fat_fd,
char *name,
fat_auxiliary_t *paux,
char *name_dir_entry
)
{
int rc = RC_OK;
ssize_t ret = 0;
msdos_fs_info_t *fs_info = mt_entry->fs_info;
uint32_t i = 0, j = 0;
uint32_t bts2rd = 0;
if (FAT_FD_OF_ROOT_DIR(fat_fd) &&
(fs_info->fat.vol.type & (FAT_FAT12 | FAT_FAT16)))
bts2rd = fat_fd->fat_file_size;
else
bts2rd = fs_info->fat.vol.bpc;
while ((ret = fat_file_read(mt_entry, fat_fd, (j * bts2rd), bts2rd,
fs_info->cl_buf)) != FAT_EOF)
{
if (ret < MSDOS_DIRECTORY_ENTRY_STRUCT_SIZE)
set_errno_and_return_minus_one(EIO);
assert(ret == bts2rd);
/* have to look at the DIR_NAME as "raw" 8-bit data */
for (i = 0; i < bts2rd; i += MSDOS_DIRECTORY_ENTRY_STRUCT_SIZE)
{
/* is the entry empty ? */
if (((*(uint8_t *)MSDOS_DIR_NAME(fs_info->cl_buf + i)) ==
MSDOS_THIS_DIR_ENTRY_AND_REST_EMPTY) ||
((*(uint8_t *)MSDOS_DIR_NAME(fs_info->cl_buf + i)) ==
MSDOS_THIS_DIR_ENTRY_EMPTY))
{
/* whether we are looking for an empty entry */
if (name == NULL)
{
/* get current cluster number */
rc = fat_file_ioctl(mt_entry, fat_fd, F_CLU_NUM,
j * bts2rd, &paux->cln);
if (rc != RC_OK)
return rc;
/* offset is computed in bytes */
paux->ofs = i;
/* write new node entry */
ret = fat_file_write(mt_entry, fat_fd, j * bts2rd + i,
MSDOS_DIRECTORY_ENTRY_STRUCT_SIZE,
(uint8_t *)name_dir_entry);
if (ret != MSDOS_DIRECTORY_ENTRY_STRUCT_SIZE)
return -1;
/*
* we don't update fat_file_size here - it should not
* increase
*/
return RC_OK;
}
/*
* if name != NULL and there is no more entries in the
* directory - return name-not-found
*/
if (((*MSDOS_DIR_NAME(fs_info->cl_buf + i)) ==
MSDOS_THIS_DIR_ENTRY_AND_REST_EMPTY))
return MSDOS_NAME_NOT_FOUND_ERR;
}
else
{
/* entry not empty and name != NULL -> compare names */
if (name != NULL)
{
if (strncmp(MSDOS_DIR_NAME((fs_info->cl_buf + i)), name,
MSDOS_SHORT_NAME_LEN) == 0)
{
/*
* we get the entry we looked for - fill auxiliary
* structure and copy all 32 bytes of the entry
*/
rc = fat_file_ioctl(mt_entry, fat_fd, F_CLU_NUM,
j * bts2rd, &paux->cln);
if (rc != RC_OK)
return rc;
/* offset is computed in bytes */
paux->ofs = i;
memcpy(name_dir_entry,(fs_info->cl_buf + i),
MSDOS_DIRECTORY_ENTRY_STRUCT_SIZE);
return RC_OK;
}
}
}
}
j++;
}
return MSDOS_NAME_NOT_FOUND_ERR;
}
