int
rtems_rfs_file_seek (rtems_rfs_file_handle* handle,
rtems_rfs_pos pos,
rtems_rfs_pos* new_pos)
{
if (rtems_rfs_trace (RTEMS_RFS_TRACE_FILE_IO))
printf ("rtems-rfs: file-seek: new=%" PRIu64 "\n", pos);
/*
* This call only sets the position if it is in a valid part of the file. The
* user can request past the end of the file then write to extend the
* file. The lseek entry states:
*
* "Although lseek() may position the file offset beyond the end of the
* file, this function does not itself extend the size of the file."
*
* This means the file needs to set the file size to the pos only when a
* write occurs.
*/
if (pos < rtems_rfs_file_shared_get_size (rtems_rfs_file_fs (handle),
handle->shared))
{
rtems_rfs_file_set_bpos (handle, pos);
/*
* If the file has a block check if it maps to the current position and it
* does not release it. That will force us to get the block at the new
* position when the I/O starts.
*/
if (rtems_rfs_buffer_handle_has_block (&handle->buffer))
{
rtems_rfs_buffer_block block;
int rc;
rc = rtems_rfs_block_map_find (rtems_rfs_file_fs (handle),
rtems_rfs_file_map (handle),
rtems_rfs_file_bpos (handle),
&block);
if (rc > 0)
return rc;
if (rtems_rfs_buffer_bnum (&handle->buffer) != block)
{
rc = rtems_rfs_buffer_handle_release (rtems_rfs_file_fs (handle),
rtems_rfs_file_buffer (handle));
if (rc > 0)
return rc;
}
}
}
else
{
/*
* The seek is outside the current file so release any buffer. A write will
* extend the file.
*/
int rc = rtems_rfs_file_io_release (handle);
if (rc > 0)
return rc;
}
*new_pos = pos;
return 0;
}
/**
* This routine processes the write() system call.
*
* @param iop
* @param buffer
* @param count
* @return ssize_t
*/
static ssize_t
rtems_rfs_rtems_file_write (rtems_libio_t* iop,
const void* buffer,
size_t count)
{
rtems_rfs_file_handle* file = rtems_rfs_rtems_get_iop_file_handle (iop);
rtems_rfs_pos pos;
rtems_rfs_pos file_size;
const uint8_t* data = buffer;
ssize_t write = 0;
int rc;
if (rtems_rfs_rtems_trace (RTEMS_RFS_RTEMS_DEBUG_FILE_WRITE))
printf("rtems-rfs: file-write: handle:%p count:%zd\n", file, count);
rtems_rfs_rtems_lock (rtems_rfs_file_fs (file));
pos = iop->offset;
file_size = rtems_rfs_file_size (file);
if (pos > file_size)
{
/*
* If the iop position is past the physical end of the file we need to set
* the file size to the new length before writing. The
* rtems_rfs_file_io_end() will grow the file subsequently.
*/
rc = rtems_rfs_file_set_size (file, pos);
if (rc)
{
rtems_rfs_rtems_unlock (rtems_rfs_file_fs (file));
return rtems_rfs_rtems_error ("file-write: write extend", rc);
}
rtems_rfs_file_set_bpos (file, pos);
}
else if (pos < file_size && rtems_libio_iop_is_append(iop))
{
pos = file_size;
rc = rtems_rfs_file_seek (file, pos, &pos);
if (rc)
{
rtems_rfs_rtems_unlock (rtems_rfs_file_fs (file));
return rtems_rfs_rtems_error ("file-write: write append seek", rc);
}
}
while (count)
{
size_t size = count;
rc = rtems_rfs_file_io_start (file, &size, false);
if (rc)
{
/*
* If we have run out of space and have written some data return that
* amount first as the inode will have accounted for it. This means
* there was no error and the return code from can be ignored.
*/
if (!write)
write = rtems_rfs_rtems_error ("file-write: write open", rc);
break;
}
if (size > count)
size = count;
memcpy (rtems_rfs_file_data (file), data, size);
data += size;
count -= size;
write += size;
rc = rtems_rfs_file_io_end (file, size, false);
if (rc)
{
write = rtems_rfs_rtems_error ("file-write: write close", rc);
break;
}
}
if (write >= 0)
iop->offset = pos + write;
rtems_rfs_rtems_unlock (rtems_rfs_file_fs (file));
return write;
}
/**
* This routine processes the write() system call.
*
* @param iop
* @param buffer
* @param count
* @return ssize_t
*/
static ssize_t
rtems_rfs_rtems_file_write (rtems_libio_t* iop,
const void* buffer,
size_t count)
{
rtems_rfs_file_handle* file = rtems_rfs_rtems_get_iop_file_handle (iop);
rtems_rfs_pos pos;
const uint8_t* data = buffer;
ssize_t write = 0;
int rc;
if (rtems_rfs_rtems_trace (RTEMS_RFS_RTEMS_DEBUG_FILE_WRITE))
printf("rtems-rfs: file-write: handle:%p count:%zd\n", file, count);
rtems_rfs_rtems_lock (rtems_rfs_file_fs (file));
pos = iop->offset;
/*
* If the iop position is past the physical end of the file we need to set
* the file size to the new length before writing. If the position equals the
* size of file we are still past the end of the file as positions number
* from 0. For a specific position we need a file that has a length of one
* more.
*/
if (pos >= rtems_rfs_file_size (file))
{
rc = rtems_rfs_file_set_size (file, pos + 1);
if (rc)
{
rtems_rfs_rtems_unlock (rtems_rfs_file_fs (file));
return rtems_rfs_rtems_error ("file-write: write extend", rc);
}
}
rtems_rfs_file_set_bpos (file, pos);
while (count)
{
size_t size = count;
rc = rtems_rfs_file_io_start (file, &size, false);
if (rc)
{
write = rtems_rfs_rtems_error ("file-write: write open", rc);
break;
}
if (size > count)
size = count;
memcpy (rtems_rfs_file_data (file), data, size);
data += size;
count -= size;
write += size;
rc = rtems_rfs_file_io_end (file, size, false);
if (rc)
{
write = rtems_rfs_rtems_error ("file-write: write close", rc);
break;
}
}
iop->size = rtems_rfs_file_size (file);
rtems_rfs_rtems_unlock (rtems_rfs_file_fs (file));
return write;
}