/*
* memfile_ftruncate
*
* This routine processes the ftruncate() system call.
*/
int memfile_ftruncate(
rtems_libio_t *iop,
off_t length
)
{
IMFS_jnode_t *the_jnode;
the_jnode = iop->pathinfo.node_access;
/*
* POSIX 1003.1b does not specify what happens if you truncate a file
* and the new length is greater than the current size. We treat this
* as an extend operation.
*/
if ( length > the_jnode->info.file.size )
return IMFS_memfile_extend( the_jnode, length );
/*
* The in-memory files do not currently reclaim memory until the file is
* deleted. So we leave the previously allocated blocks in place for
* future use and just set the length.
*/
the_jnode->info.file.size = length;
iop->size = the_jnode->info.file.size;
IMFS_update_atime( the_jnode );
return 0;
}
static ssize_t IMFS_fifo_read(
rtems_libio_t *iop,
void *buffer,
size_t count
)
{
IMFS_jnode_t *jnode = iop->pathinfo.node_access;
int err = pipe_read(JNODE2PIPE(jnode), buffer, count, iop);
if (err > 0)
IMFS_update_atime(jnode);
IMFS_FIFO_RETURN(err);
}
ssize_t IMFS_fifo_read(
epos_libio_t *iop,
void *buffer,
size_t count
)
{
IMFS_jnode_t *jnode = iop->file_info;
int err = pipe_read(JNODE2PIPE(jnode), buffer, count, iop);
if (err > 0)
IMFS_update_atime(jnode);
IMFS_FIFO_RETURN(err);
}
/*
* IMFS_memfile_read
*
* This routine read from memory file pointed to by the_jnode into
* the specified data buffer specified by destination. The file
* is NOT extended. An offset greater than the length of the file
* is considered an error. Read from an offset for more bytes than
* are between the offset and the end of the file will result in
* reading the data between offset and the end of the file (truncated
* read).
*/
static ssize_t IMFS_memfile_read(
IMFS_file_t *file,
off_t start,
unsigned char *destination,
unsigned int length
)
{
block_p *block_ptr;
unsigned int block;
unsigned int my_length;
unsigned int to_copy = 0;
unsigned int last_byte;
unsigned int copied;
unsigned int start_offset;
unsigned char *dest;
dest = destination;
/*
* Perform internal consistency checks
*/
IMFS_assert( file );
IMFS_assert( dest );
/*
* Linear files (as created from a tar file are easier to handle
* than block files).
*/
my_length = length;
/*
* If the last byte we are supposed to read is past the end of this
* in memory file, then shorten the length to read.
*/
last_byte = start + length;
if ( last_byte > file->Memfile.File.size )
my_length = file->Memfile.File.size - start;
copied = 0;
/*
* Three phases to the read:
* + possibly the last part of one block
* + all of zero of more blocks
* + possibly the first part of one block
*/
/*
* Phase 1: possibly the last part of one block
*/
start_offset = start % IMFS_MEMFILE_BYTES_PER_BLOCK;
block = start / IMFS_MEMFILE_BYTES_PER_BLOCK;
if ( start_offset ) {
to_copy = IMFS_MEMFILE_BYTES_PER_BLOCK - start_offset;
if ( to_copy > my_length )
to_copy = my_length;
block_ptr = IMFS_memfile_get_block_pointer( &file->Memfile, block, 0 );
if ( !block_ptr )
return copied;
memcpy( dest, &(*block_ptr)[ start_offset ], to_copy );
dest += to_copy;
block++;
my_length -= to_copy;
copied += to_copy;
}
/*
* Phase 2: all of zero of more blocks
*/
to_copy = IMFS_MEMFILE_BYTES_PER_BLOCK;
while ( my_length >= IMFS_MEMFILE_BYTES_PER_BLOCK ) {
block_ptr = IMFS_memfile_get_block_pointer( &file->Memfile, block, 0 );
if ( !block_ptr )
return copied;
memcpy( dest, &(*block_ptr)[ 0 ], to_copy );
dest += to_copy;
block++;
my_length -= to_copy;
copied += to_copy;
}
/*
* Phase 3: possibly the first part of one block
*/
IMFS_assert( my_length < IMFS_MEMFILE_BYTES_PER_BLOCK );
if ( my_length ) {
block_ptr = IMFS_memfile_get_block_pointer( &file->Memfile, block, 0 );
if ( !block_ptr )
return copied;
memcpy( dest, &(*block_ptr)[ 0 ], my_length );
copied += my_length;
}
IMFS_update_atime( &file->Node );
return copied;
}
MEMFILE_STATIC ssize_t IMFS_memfile_read(
IMFS_jnode_t *the_jnode,
off_t start,
unsigned char *destination,
unsigned int length
)
{
block_p *block_ptr;
unsigned int block;
unsigned int my_length;
unsigned int to_copy = 0;
unsigned int last_byte;
unsigned int copied;
unsigned int start_offset;
unsigned char *dest;
dest = destination;
/*
* Perform internal consistency checks
*/
assert( the_jnode );
if ( !the_jnode )
rtems_set_errno_and_return_minus_one( EIO );
assert( the_jnode->type == IMFS_MEMORY_FILE ||
the_jnode->type == IMFS_LINEAR_FILE );
if ( the_jnode->type != IMFS_MEMORY_FILE &&
the_jnode->type != IMFS_LINEAR_FILE )
rtems_set_errno_and_return_minus_one( EIO );
/*
* Error checks on arguments
*/
assert( dest );
if ( !dest )
rtems_set_errno_and_return_minus_one( EINVAL );
/*
* If there is nothing to read, then quick exit.
*/
my_length = length;
if ( !my_length )
rtems_set_errno_and_return_minus_one( EINVAL );
/*
* Linear files (as created from a tar file are easier to handle
* than block files).
*/
if (the_jnode->type == IMFS_LINEAR_FILE) {
unsigned char *file_ptr;
file_ptr = (unsigned char *)the_jnode->info.linearfile.direct;
if (my_length > (the_jnode->info.linearfile.size - start))
my_length = the_jnode->info.linearfile.size - start;
memcpy(dest, &file_ptr[start], my_length);
IMFS_update_atime( the_jnode );
return my_length;
}
/*
* If the last byte we are supposed to read is past the end of this
* in memory file, then shorten the length to read.
*/
last_byte = start + length;
if ( last_byte > the_jnode->info.file.size )
my_length = the_jnode->info.file.size - start;
copied = 0;
/*
* Three phases to the read:
* + possibly the last part of one block
* + all of zero of more blocks
* + possibly the first part of one block
*/
/*
* Phase 1: possibly the last part of one block
*/
start_offset = start % IMFS_MEMFILE_BYTES_PER_BLOCK;
block = start / IMFS_MEMFILE_BYTES_PER_BLOCK;
if ( start_offset ) {
to_copy = IMFS_MEMFILE_BYTES_PER_BLOCK - start_offset;
if ( to_copy > my_length )
to_copy = my_length;
block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 );
assert( block_ptr );
if ( !block_ptr )
return copied;
memcpy( dest, &(*block_ptr)[ start_offset ], to_copy );
dest += to_copy;
block++;
my_length -= to_copy;
copied += to_copy;
}
/*
* Phase 2: all of zero of more blocks
*/
to_copy = IMFS_MEMFILE_BYTES_PER_BLOCK;
while ( my_length >= IMFS_MEMFILE_BYTES_PER_BLOCK ) {
block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 );
assert( block_ptr );
if ( !block_ptr )
return copied;
memcpy( dest, &(*block_ptr)[ 0 ], to_copy );
dest += to_copy;
block++;
my_length -= to_copy;
copied += to_copy;
}
/*
* Phase 3: possibly the first part of one block
*/
assert( my_length < IMFS_MEMFILE_BYTES_PER_BLOCK );
if ( my_length ) {
block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 );
assert( block_ptr );
if ( !block_ptr )
return copied;
memcpy( dest, &(*block_ptr)[ 0 ], my_length );
copied += my_length;
}
IMFS_update_atime( the_jnode );
return copied;
}