/*

 * Copyright (c) 1998,1999,2000

 *	Traakan, Inc., Los Altos, CA

 *	All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice unmodified, this list of conditions, and the following

 *    disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

/*

 * Project:  NDMJOB

 * Ident:    $Id: $

 *

 * Description:

 *

 */

#include "ndmagents.h"

#ifndef NDMOS_OPTION_NO_TAPE_AGENT

/*

 * Initialization and Cleanup

 ****************************************************************

 */

/* Initialize -- Set data structure to know value, ignore current value */

int

ndmta_initialize (struct ndm_session *sess)

{

	struct ndm_tape_agent *	ta = &sess->tape_acb;

	int			rc;

	NDMOS_MACRO_ZEROFILL(ta);

	ndmta_commission (sess);

	rc = ndmos_tape_initialize (sess);

	if (rc) return rc;

	return 0;

}

/* Commission -- Get agent ready. Entire session has been initialize()d */

int

ndmta_commission (struct ndm_session *sess)

{

	ndmta_init_mover_state (sess);

	return 0;

}

/* Decommission -- Discard agent */

int

ndmta_decommission (struct ndm_session *sess)

{

	ndmis_tape_close (sess);

	ndmta_commission (sess);

	return 0;

}

/* helper for mover state */

int

ndmta_init_mover_state (struct ndm_session *sess)

{

	struct ndm_tape_agent *	ta = &sess->tape_acb;

	NDMOS_MACRO_ZEROFILL (&ta->mover_state);

	ta->mover_state.state = NDMP9_MOVER_STATE_IDLE;

	ta->mover_state.window_offset = 0;

	ta->mover_state.record_num = 0; /* this should probably be -1, but spec says 0 */

	ta->mover_state.record_size = 20*512;	/* traditional tar default */

	ta->mover_state.window_length = NDMP_LENGTH_INFINITY;

	ta->mover_window_end = NDMP_LENGTH_INFINITY;

	ta->mover_want_pos = 0;

	ta->tb_blockno = -1;

	return 0;

}

/*

 * Semantic actions -- called from ndma_dispatch()

 ****************************************************************

 */

void

ndmta_mover_sync_state (struct ndm_session *sess)

{

	ndmos_tape_sync_state (sess);

}

ndmp9_error

ndmta_mover_listen (struct ndm_session *sess, ndmp9_mover_mode mover_mode)

{

	struct ndm_tape_agent *	ta = &sess->tape_acb;

	ta->mover_state.mode = mover_mode;

	ta->mover_state.state = NDMP9_MOVER_STATE_LISTEN;

	ta->mover_state.halt_reason = NDMP9_MOVER_HALT_NA;

	ta->mover_state.pause_reason = NDMP9_MOVER_PAUSE_NA;

	return NDMP9_NO_ERR;

}

ndmp9_error

ndmta_mover_connect (struct ndm_session *sess, ndmp9_mover_mode mover_mode)

{

	struct ndm_tape_agent *	ta = &sess->tape_acb;

	ta->mover_state.mode = mover_mode;

	ndmta_mover_start_active (sess);

	return NDMP9_NO_ERR;

}

void

ndmta_mover_halt (struct ndm_session *sess, ndmp9_mover_halt_reason reason)

{

	struct ndm_tape_agent *	ta = &sess->tape_acb;

	ta->mover_state.state = NDMP9_MOVER_STATE_HALTED;

	ta->mover_state.halt_reason = reason;

	ta->mover_state.pause_reason = NDMP9_MOVER_PAUSE_NA;

	ta->pending_change_after_drain = 0;

	ta->mover_notify_pending = 1;

	ndmis_tape_close (sess);

}

void

ndmta_mover_pause (struct ndm_session *sess, ndmp9_mover_pause_reason reason)

{

	struct ndm_tape_agent *	ta = &sess->tape_acb;

	ta->mover_state.state = NDMP9_MOVER_STATE_PAUSED;

	ta->mover_state.halt_reason = NDMP9_MOVER_HALT_NA;

	ta->mover_state.pause_reason = reason;

	ta->pending_change_after_drain = 0;

	ta->mover_notify_pending = 1;

}

void

ndmta_mover_pending (struct ndm_session *sess,

  ndmp9_mover_state pending_state,

  ndmp9_mover_halt_reason halt_reason,

  ndmp9_mover_pause_reason pause_reason)

{

	struct ndm_tape_agent *	ta = &sess->tape_acb;

	if (ta->pending_change_after_drain) {

		/* internal botch */

	}

	ta->pending_mover_state = pending_state;

	ta->pending_mover_halt_reason = halt_reason;

	ta->pending_mover_pause_reason = pause_reason;

	ta->pending_change_after_drain = 1;

}

void

ndmta_mover_apply_pending (struct ndm_session *sess)

{

	struct ndm_tape_agent *	ta = &sess->tape_acb;

	if (!ta->pending_change_after_drain) {

		/* internal botch */

	}

	ta->mover_state.state = ta->pending_mover_state;

	ta->mover_state.halt_reason = ta->pending_mover_halt_reason;

	ta->mover_state.pause_reason = ta->pending_mover_pause_reason;

	ta->pending_change_after_drain = 0;

	ta->mover_notify_pending = 1;

}

void

ndmta_mover_halt_pending (struct ndm_session *sess,

  ndmp9_mover_halt_reason halt_reason)

{

	ndmta_mover_pending (sess, NDMP9_MOVER_STATE_HALTED,

		halt_reason, NDMP9_MOVER_PAUSE_NA);

}

void

ndmta_mover_pause_pending (struct ndm_session *sess,

  ndmp9_mover_pause_reason pause_reason)

{

	ndmta_mover_pending (sess, NDMP9_MOVER_STATE_PAUSED,

		NDMP9_MOVER_HALT_NA, pause_reason);

}

void

ndmta_mover_active (struct ndm_session *sess)

{

	struct ndm_tape_agent *	ta = &sess->tape_acb;

	ta->mover_state.state = NDMP9_MOVER_STATE_ACTIVE;

	ta->mover_state.halt_reason = NDMP9_MOVER_HALT_NA;

	ta->mover_state.pause_reason = NDMP9_MOVER_PAUSE_NA;

	ta->tb_blockno = -1;	/* always mistrust after activating */

}

void

ndmta_mover_start_active (struct ndm_session *sess)

{

	struct ndm_tape_agent *	ta = &sess->tape_acb;

	ndmalogf (sess, 0, 6, "mover going active");

	ndma_send_logmsg(sess, NDMP9_LOG_DEBUG, sess->plumb.control,

		"mover going active");

	switch (ta->mover_state.mode) {

	case NDMP9_MOVER_MODE_READ:

		ndmis_tape_start (sess, NDMCHAN_MODE_READ);

		ndmta_mover_active (sess);

		break;

	case NDMP9_MOVER_MODE_WRITE:

		ndmis_tape_start (sess, NDMCHAN_MODE_WRITE);

		ndmta_mover_active (sess);

		break;

	default:

		ndmalogf (sess, 0, 0, "BOTCH mover listen, unknown mode");

		break;

	}

}

void

ndmta_mover_stop (struct ndm_session *sess)

{

	ndmta_init_mover_state (sess);

}

void

ndmta_mover_abort (struct ndm_session *sess)

{

	ndmta_mover_halt (sess, NDMP9_MOVER_HALT_ABORTED);

}

void

ndmta_mover_continue (struct ndm_session *sess)

{

	ndmta_mover_active (sess);

}

void

ndmta_mover_close (struct ndm_session *sess)

{

	struct ndm_tape_agent *	ta = &sess->tape_acb;

	if (ta->mover_state.state != NDMP9_MOVER_STATE_HALTED)

		ndmta_mover_halt (sess, NDMP9_MOVER_HALT_CONNECT_CLOSED);

}

void

ndmta_mover_read (struct ndm_session *sess,

  unsigned long long offset, unsigned long long length)

{

	struct ndm_tape_agent *	ta = &sess->tape_acb;

	ta->mover_state.seek_position = offset;

	ta->mover_state.bytes_left_to_read = length;

	ta->mover_want_pos = offset;

}

/*

 * Quantum -- get a bit of work done

 ****************************************************************

 */

int

ndmta_quantum (struct ndm_session *sess)

{

	struct ndm_tape_agent *	ta = &sess->tape_acb;

	int			rc = 0;	/* did nothing */

	switch (ta->mover_state.state) {

	default:

		ndmalogf (sess, 0, 0, "BOTCH mover state");

		return -1;

	case NDMP9_MOVER_STATE_IDLE:

	case NDMP9_MOVER_STATE_PAUSED:

	case NDMP9_MOVER_STATE_HALTED:

		break;

	case NDMP9_MOVER_STATE_LISTEN:

		switch (sess->plumb.image_stream.tape_ep.connect_status) {

		case NDMIS_CONN_LISTEN:		/* no connection yet */

			break;

		case NDMIS_CONN_ACCEPTED:	/* we're in business */

			ndmta_mover_start_active (sess);

			rc = 1;		/* did something */

			break;

		case NDMIS_CONN_BOTCHED:	/* accept() went south */

		default:			/* ain't suppose to happen */

			ndmta_mover_halt(sess,NDMP9_MOVER_HALT_CONNECT_ERROR);

			break;

		}

		break;

	case NDMP9_MOVER_STATE_ACTIVE:

		switch (ta->mover_state.mode) {

		case NDMP9_MOVER_MODE_READ:

			rc = ndmta_read_quantum (sess);

			break;

		case NDMP9_MOVER_MODE_WRITE:

			rc = ndmta_write_quantum (sess);

			break;

		default:

			ndmalogf (sess, 0, 0,

				"BOTCH mover active, unknown mode");

			return -1;

		}

		break;

	}

	ndmta_mover_send_notice (sess);

	return rc;

}

int

ndmta_read_quantum (struct ndm_session *sess)

{

	struct ndm_tape_agent *	ta = &sess->tape_acb;

	struct ndmchan *	ch = &sess->plumb.image_stream.chan;

	unsigned long		count = ta->mover_state.record_size;

	int			did_something = 0;

	unsigned		n_ready;

	char *			data;

	unsigned long		done_count;

	ndmp9_error		error;

  again:

	n_ready = ndmchan_n_ready (ch);

	if (ch->eof) {

		if (n_ready == 0) {

			/* done */

			if (ch->saved_errno)

				ndmta_mover_halt (sess,

					NDMP9_MOVER_HALT_CONNECT_ERROR);

			else

				ndmta_mover_halt (sess,

					NDMP9_MOVER_HALT_CONNECT_CLOSED);

			did_something++;

			return did_something;

		}

		if (n_ready < count) {

			int		n_pad = count - n_ready;

			int		n_avail;

			while (n_pad > 0) {

				n_avail = ndmchan_n_avail (ch);

				if (n_avail == 0) {

					/* Uh-oh */

				}

				data = &ch->data[ch->end_ix];

				if (n_avail > n_pad)

					n_avail = n_pad;

				bzero (data, n_avail);

				ch->end_ix += n_avail;

				n_pad -= n_avail;

			}

			n_ready = ndmchan_n_ready (ch);

		}

	}

	if (n_ready < count) {

		return did_something;	/* blocked */

	}

	if (ta->mover_want_pos >= ta->mover_window_end) {

		ndmta_mover_pause (sess, NDMP9_MOVER_PAUSE_SEEK);

		did_something++;

		return did_something;

	}

	data = &ch->data[ch->beg_ix];

	done_count = 0;

	error = ndmos_tape_write (sess, data, count, &done_count);

	switch (error) {

	case NDMP9_NO_ERR:

		if (done_count != count) {

			/* This ain't suppose to happen */

		}

		ta->mover_state.bytes_moved += count;

		/* note this is calculated before mover_want_pos is incremented, since

		 * record_num is the *last* block processed */

		/* ta->mover_state.record_num = ta->mover_want_pos / ta->mover_state.record_size; */

		/* It was a bug, set record_num after mover_want_pos */

		ta->mover_want_pos += count;

		ta->mover_state.record_num = ta->mover_want_pos / ta->mover_state.record_size;

		ch->beg_ix += count;

		did_something++;

		goto again;	/* write as much to tape as possible */

	case NDMP9_EOM_ERR:

		ndmta_mover_pause (sess, NDMP9_MOVER_PAUSE_EOM);

		did_something++;

		break;

	default:

		ndmta_mover_halt (sess, NDMP9_MOVER_HALT_MEDIA_ERROR);

		did_something++;

		break;

	}

	return did_something;

}

int

ndmta_write_quantum (struct ndm_session *sess)

{

	struct ndm_tape_agent *	ta = &sess->tape_acb;

	struct ndmchan *	ch = &sess->plumb.image_stream.chan;

	unsigned long		count = ta->mover_state.record_size;

	int			did_something = 0;

	unsigned long long	max_read;

	unsigned long long	want_window_off;

	unsigned long		block_size;

	unsigned long		want_blockno;

	unsigned long		cur_blockno;

	unsigned		n_avail, n_read, record_off;

	char *			data;

	unsigned long		done_count = 0;

	ndmp9_error		error;

  again:

	n_read = n_avail = ndmchan_n_avail_record (ch, count);

	if (n_avail < count) {

		/* allow to drain */

		return did_something;

	}

	if (ta->pending_change_after_drain) {

		if (ndmchan_n_ready (ch) > 0) {

			/* allow to drain */

		} else {

			ndmta_mover_apply_pending (sess);

			did_something++;

		}

		return did_something;

	}

	if (n_read > ta->mover_state.bytes_left_to_read)

		n_read = ta->mover_state.bytes_left_to_read;

	if (n_read < count) {

		/* Active, but paused awaiting MOVER_READ request */

		return did_something;	/* mover blocked */

	}

	if (ta->mover_want_pos < ta->mover_state.window_offset

	 || ta->mover_want_pos >= ta->mover_window_end) {

		ndmta_mover_pause_pending (sess, NDMP9_MOVER_PAUSE_SEEK);

		goto again;

	}

	max_read = ta->mover_window_end - ta->mover_want_pos;

	if (n_read > max_read)

		n_read = max_read;

	want_window_off = ta->mover_want_pos - ta->mover_state.window_offset;

	/* make an estimate of the block size - the tape agent's block size, or

	 * if it's in variable block size mode, the mover's record size: "When

	 * in variable block mode, as indicated by a tape block_size value of

	 * zero, the mover record size defines the actual block size used by

	 * the tape subsystem." (NDMPv4 RFC, Section 3.6.2.1) */

	block_size = ta->tape_state.block_size.value;

	if (!block_size)

		block_size = ta->mover_state.record_size;

	want_blockno = ta->mover_window_first_blockno + want_window_off / block_size;

	if (ta->tb_blockno != want_blockno) {

		unsigned long	xsr_count, xsr_resid;

		ndmos_tape_sync_state(sess);

		cur_blockno = ta->tape_state.blockno.value;

		if (cur_blockno < want_blockno) {

			xsr_count = want_blockno - cur_blockno;

			error = ndmos_tape_mtio (sess, NDMP9_MTIO_FSR,

						xsr_count, &xsr_resid);

			if (error == NDMP9_EOF_ERR) {

				ndmta_mover_pause_pending (sess,

						NDMP9_MOVER_PAUSE_EOF);

				goto again;

			}

			if (error != NDMP9_NO_ERR) {

				ndmta_mover_halt_pending (sess,

						NDMP9_MOVER_HALT_MEDIA_ERROR);

				goto again;

			}

			if (xsr_resid > 0) {

				ndmta_mover_pause_pending (sess,

						NDMP9_MOVER_PAUSE_EOF);

				goto again;

			}

		} else if (cur_blockno > want_blockno) {

			xsr_count = cur_blockno - want_blockno;

			error = ndmos_tape_mtio (sess, NDMP9_MTIO_BSR,

						xsr_count, &xsr_resid);

			if (error != NDMP9_NO_ERR || xsr_resid > 0) {

				ndmta_mover_halt_pending (sess,

						NDMP9_MOVER_HALT_MEDIA_ERROR);

				goto again;

			}

		} else {

			/* in position */

		}

		data = ta->tape_buffer;

		done_count = 0;

		error = ndmos_tape_read (sess, data, count, &done_count);

		did_something++;

		if (error == NDMP9_EOF_ERR) {

			ndmta_mover_pause_pending (sess,

						NDMP9_MOVER_PAUSE_EOF);

			goto again;

		}

		/* N.B. - handling of done_count = 0 here is hacked to support

		 * non-blocking writes to a socket in amndmjob */

		if (error != NDMP9_NO_ERR) {

			ndmta_mover_halt_pending (sess,

				NDMP9_MOVER_HALT_MEDIA_ERROR);

			goto again;

		}

		if (done_count == 0) {

			return did_something - 1;

		}

		if (done_count != count) {

			n_read = done_count;

			goto again;

		}

		ta->tb_blockno = want_blockno;

		/* re-calcluate this, since record_size may be > block_size, in which

		 * case the record_num may not change for each block read from tape */

		ta->mover_state.record_num = ta->mover_want_pos / ta->mover_state.record_size;

	}

	record_off = ta->mover_want_pos % ta->mover_state.record_size;

	n_avail = ta->mover_state.record_size - record_off;

	if (n_read > n_avail)

		n_read = n_avail;

	if (n_read != done_count) {

		dbprintf("lost %lu bytes %lu %u\n", done_count - n_read, done_count, n_read);

		n_read = done_count;

	}

	data = &ta->tape_buffer[record_off];

	bcopy (data, ch->data + ch->end_ix, n_read);

	ch->end_ix += n_read;

	ta->mover_state.bytes_moved += n_read;

	ta->mover_want_pos += n_read;

	ta->mover_state.bytes_left_to_read -= n_read;

	did_something++;

	goto again;	/* do as much as possible */

}

void

ndmta_mover_send_notice (struct ndm_session *sess)

{

	struct ndm_tape_agent *	ta = &sess->tape_acb;

	if (!ta->mover_notify_pending)

		return;

	ta->mover_notify_pending = 0;

	switch (ta->mover_state.state) {

	case NDMP9_MOVER_STATE_HALTED:

		ndma_notify_mover_halted (sess);

		break;

	case NDMP9_MOVER_STATE_PAUSED:

		ndma_notify_mover_paused (sess);

		break;

	default:

		/* Hmm. Why are we here. Race? */

		break;

	}

}

#endif /* !NDMOS_OPTION_NO_TAPE_AGENT */