int vfs_write(openfile_t file, void *buffer, int datasize)
{
openfile_entry_t *openfile;
fs_t *fs;
int ret;
if (vfs_start_op() != VFS_OK)
return VFS_UNUSABLE;
openfile = vfs_verify_open(file);
fs = openfile->filesystem;
KERNEL_ASSERT(datasize >= 0 && buffer != NULL);
ret = fs->write(fs, openfile->fileid, buffer, datasize,
openfile->seek_position);
if(ret > 0) {
semaphore_P(openfile_table.sem);
openfile->seek_position += ret;
semaphore_V(openfile_table.sem);
}
vfs_end_op();
return ret;
}
/**
* Seek given file to given position. The position is not verified
* to be within the file's size.
*
* @param file Open file
*
* @param seek_position New positive seek position.
*
* @return VFS_OK, panics on invalid arguments.
*
*/
int vfs_seek(openfile_t file, int seek_position)
{
openfile_entry_t *openfile;
if (vfs_start_op() != VFS_OK)
return VFS_UNUSABLE;
if(seek_position < 0) {
return VFS_INVALID_PARAMS;
}
semaphore_P(openfile_table.sem);
openfile = vfs_verify_open(file);
if (openfile == NULL) {
semaphore_V(openfile_table.sem);
return VFS_NOT_OPEN;
}
openfile->seek_position = seek_position;
semaphore_V(openfile_table.sem);
vfs_end_op();
return VFS_OK;
}
/**
* Close open file.
*
* @param file Openfile id
*
* @return VFS_OK on success, negative (VFS_*) on error.
*
*/
int vfs_close(openfile_t file)
{
openfile_entry_t *openfile;
fs_t *fs;
int ret;
if (vfs_start_op() != VFS_OK)
return VFS_UNUSABLE;
semaphore_P(openfile_table.sem);
openfile = vfs_verify_open(file);
if (openfile == NULL) {
semaphore_V(openfile_table.sem);
return VFS_NOT_OPEN;
}
fs = openfile->filesystem;
ret = fs->close(fs, openfile->fileid);
openfile->filesystem = NULL;
semaphore_V(openfile_table.sem);
vfs_end_op();
return ret;
}
int vfs_seek(openfile_t file, int seek_position)
{
openfile_entry_t *openfile;
if (vfs_start_op() != VFS_OK)
return VFS_UNUSABLE;
KERNEL_ASSERT(seek_position >= 0);
semaphore_P(openfile_table.sem);
openfile = vfs_verify_open(file);
openfile->seek_position = seek_position;
semaphore_V(openfile_table.sem);
vfs_end_op();
return VFS_OK;
}
/**
* Tells the given file's position.
*
* @param file Open file
*
* @return the file's seek position. Negative values on error
*
*/
int vfs_tell(openfile_t file)
{
openfile_entry_t *openfile;
if (vfs_start_op() != VFS_OK)
return VFS_UNUSABLE;
semaphore_P(openfile_table.sem);
openfile = vfs_verify_open(file);
if (openfile == NULL) {
semaphore_V(openfile_table.sem);
return VFS_NOT_OPEN;
}
int seek_position = openfile->seek_position;
semaphore_V(openfile_table.sem);
vfs_end_op();
return seek_position;
}
/**
* Writes datasize bytes from given buffer to given open file.
* The write is started from current seek position and after writing, the
* position is updated.
*
* @param file Open file
*
* @param buffer Buffer to be written to file.
*
* @param datasize Number of bytes to write.
*
* @return Number of bytes written. All bytes are written unless error
* prevented to do that. Negative values are specific error conditions.
*
*/
int vfs_write(openfile_t file, void *buffer, int datasize)
{
openfile_entry_t *openfile;
fs_t *fs;
int fileid, seek_position, ret;
if (datasize < 0 || buffer == NULL) {
return VFS_INVALID_PARAMS;
}
if (vfs_start_op() != VFS_OK)
return VFS_UNUSABLE;
semaphore_P(openfile_table.sem);
openfile = vfs_verify_open(file);
if (openfile == NULL) {
semaphore_V(openfile_table.sem);
return VFS_NOT_OPEN;
}
fs = openfile->filesystem;
fileid = openfile->fileid;
seek_position = openfile->seek_position;
semaphore_V(openfile_table.sem);
ret = fs->write(fs, fileid, buffer, datasize, seek_position);
if(ret > 0) {
semaphore_P(openfile_table.sem);
openfile->seek_position += ret;
semaphore_V(openfile_table.sem);
}
vfs_end_op();
return ret;
}
