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Stop binding audio devices exposed by sndiod to physical devices

This a shift towards a new model: clients connect to logical devices
(created with -s option) then the server routes data to/from the
underlying physical device (registered with -f option). The binding
may be changed at run-time with the server.device control exposed by
sndioctl(1).

As audio devices exposed by sndiod(8) are not bound to fixed physical
devices anymore, the physical audio device number component of
sndio(7) descriptors was removed.

fixes, help from and ok denis, edd

/*	$OpenBSD: midi.c,v 1.29 2021/11/01 14:43:25 ratchov Exp $	*/
/*
 * Copyright (c) 2008-2012 Alexandre Ratchov <alex@caoua.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "abuf.h"
#include "defs.h"
#include "dev.h"
#include "file.h"
#include "midi.h"
#include "miofile.h"
#include "sysex.h"
#include "utils.h"

int  port_open(struct port *);
void port_imsg(void *, unsigned char *, int);
void port_omsg(void *, unsigned char *, int);
void port_fill(void *, int);
void port_exit(void *);
void port_exitall(struct port *);

struct midiops port_midiops = {
	port_imsg,
	port_omsg,
	port_fill,
	port_exit
};

#define MIDI_NEP 32
struct midi midi_ep[MIDI_NEP];
struct port *port_list = NULL;
unsigned int midi_portnum = 0;

struct midithru {
	unsigned int txmask, rxmask;
#define MIDITHRU_NMAX 32
} midithru[MIDITHRU_NMAX];

/*
 * length of voice and common messages (status byte included)
 */
const unsigned int voice_len[] = { 3, 3, 3, 3, 2, 2, 3 };
const unsigned int common_len[] = { 0, 2, 3, 2, 0, 0, 1, 1 };

void
midi_log(struct midi *ep)
{
	log_puts("midi");
	log_putu(ep - midi_ep);
}

void
midi_init(void)
{
}

void
midi_done(void)
{
}

struct midi *
midi_new(struct midiops *ops, void *arg, int mode)
{
	int i;
	struct midi *ep;

	for (i = 0, ep = midi_ep;; i++, ep++) {
		if (i == MIDI_NEP)
			return NULL;
		if (ep->ops == NULL)
			break;
	}
	ep->ops = ops;
	ep->arg = arg;
	ep->used = 0;
	ep->len = 0;
	ep->idx = 0;
	ep->st = 0;
	ep->last_st = 0;
	ep->txmask = 0;
	ep->self = 1 << i;
	ep->tickets = 0;
	ep->mode = mode;

	/*
	 * the output buffer is the client input
	 */
	if (ep->mode & MODE_MIDIIN)
		abuf_init(&ep->obuf, MIDI_BUFSZ);
	midi_tickets(ep);
	return ep;
}

void
midi_del(struct midi *ep)
{
	int i;
	struct midi *peer;

	ep->txmask = 0;
	for (i = 0; i < MIDI_NEP; i++) {
		peer = midi_ep + i;
		if (peer->txmask & ep->self) {
			peer->txmask &= ~ep->self;
			midi_tickets(peer);
		}
	}
	for (i = 0; i < MIDITHRU_NMAX; i++) {
		midithru[i].txmask &= ~ep->self;
		midithru[i].rxmask &= ~ep->self;
	}
	ep->ops = NULL;
	if (ep->mode & MODE_MIDIIN) {
		abuf_done(&ep->obuf);
	}
}

/*
 * connect two midi endpoints
 */
void
midi_link(struct midi *ep, struct midi *peer)
{
	if (ep->mode & MODE_MIDIOUT) {
		ep->txmask |= peer->self;
		midi_tickets(ep);
	}
	if (ep->mode & MODE_MIDIIN) {
#ifdef DEBUG
		if (ep->obuf.used > 0) {
			midi_log(ep);
			log_puts(": linked with non-empty buffer\n");
			panic();
		}
#endif
		/* ep has empty buffer, so no need to call midi_tickets() */
		peer->txmask |= ep->self;
	}
}

/*
 * add the midi endpoint in the ``tag'' midi thru box
 */
void
midi_tag(struct midi *ep, unsigned int tag)
{
	struct midi *peer;
	struct midithru *t = midithru + tag;
	int i;

	if (ep->mode & MODE_MIDIOUT) {
		ep->txmask |= t->txmask;
		midi_tickets(ep);
	}
	if (ep->mode & MODE_MIDIIN) {
#ifdef DEBUG
		if (ep->obuf.used > 0) {
			midi_log(ep);
			log_puts(": tagged with non-empty buffer\n");
			panic();
		}
#endif
		for (i = 0; i < MIDI_NEP; i++) {
			if (!(t->rxmask & (1 << i)))
				continue;
			peer = midi_ep + i;
			peer->txmask |= ep->self;
		}
	}
	if (ep->mode & MODE_MIDIOUT)
		t->rxmask |= ep->self;
	if (ep->mode & MODE_MIDIIN)
		t->txmask |= ep->self;
}

/*
 * return the list of tags
 */
unsigned int
midi_tags(struct midi *ep)
{
	int i;
	struct midithru *t;
	unsigned int tags;

	tags = 0;
	for (i = 0; i < MIDITHRU_NMAX; i++) {
		t = midithru + i;
		if ((t->txmask | t->rxmask) & ep->self)
			tags |= 1 << i;
	}
	return tags;
}

/*
 * broadcast the given message to other endpoints
 */
void
midi_send(struct midi *iep, unsigned char *msg, int size)
{
	struct midi *oep;
	int i;

#ifdef DEBUG
	if (log_level >= 4) {
		midi_log(iep);
		log_puts(": sending:");
		for (i = 0; i < size; i++) {
			log_puts(" ");
			log_putx(msg[i]);
		}
		log_puts("\n");
	}
#endif
	for (i = 0; i < MIDI_NEP ; i++) {
		if ((iep->txmask & (1 << i)) == 0)
			continue;
		oep = midi_ep + i;
		if (msg[0] <= 0x7f) {
			if (oep->owner != iep)
				continue;
		} else if (msg[0] <= 0xf7)
			oep->owner = iep;
#ifdef DEBUG
		if (log_level >= 4) {
			midi_log(iep);
			log_puts(" -> ");
			midi_log(oep);
			log_puts("\n");
		}
#endif
		oep->ops->omsg(oep->arg, msg, size);
	}
}

/*
 * determine if we have gained more input tickets, and if so call the
 * fill() call-back to notify the i/o layer that it can send more data
 */
void
midi_tickets(struct midi *iep)
{
	int i, tickets, avail, maxavail;
	struct midi *oep;

	/*
	 * don't request iep->ops->fill() too often as it generates
	 * useless network traffic: wait until we reach half of the
	 * max tickets count. As in the worst case (see comment below)
	 * one ticket may consume two bytes, the max ticket count is
	 * BUFSZ / 2 and halt of it is simply BUFSZ / 4.
	 */
	if (iep->tickets >= MIDI_BUFSZ / 4)
		return;

	maxavail = MIDI_BUFSZ;
	for (i = 0; i < MIDI_NEP ; i++) {
		if ((iep->txmask & (1 << i)) == 0)
			continue;
		oep = midi_ep + i;
		avail = oep->obuf.len - oep->obuf.used;
		if (maxavail > avail)
			maxavail = avail;
	}

	/*
	 * in the worst case output message is twice the
	 * input message (2-byte messages with running status)
	 */
	tickets = maxavail / 2 - iep->tickets;
	if (tickets > 0) {
		iep->tickets += tickets;
		iep->ops->fill(iep->arg, tickets);
	}
}

/*
 * recalculate tickets of endpoints sending data to this one
 */
void
midi_fill(struct midi *oep)
{
	int i;
	struct midi *iep;

	for (i = 0; i < MIDI_NEP; i++) {
		iep = midi_ep + i;
		if (iep->txmask & oep->self)
			midi_tickets(iep);
	}
}

/*
 * parse then give data chunk, and calling imsg() for each message
 */
void
midi_in(struct midi *iep, unsigned char *idata, int icount)
{
	int i;
	unsigned char c;

	for (i = 0; i < icount; i++) {
		c = *idata++;
		if (c >= 0xf8) {
			if (c != MIDI_ACK)
				iep->ops->imsg(iep->arg, &c, 1);
		} else if (c == SYSEX_END) {
			if (iep->st == SYSEX_START) {
				iep->msg[iep->idx++] = c;
				iep->ops->imsg(iep->arg, iep->msg, iep->idx);
			}

			/*
			 * There are bogus MIDI sources that keep
			 * state across sysex; Linux virmidi ports fed
			 * by the sequencer is an example. We
			 * workaround this by saving the current
			 * status and restoring it at the end of the
			 * sysex.
			 */
			iep->st = iep->last_st;
			if (iep->st)
				iep->len = voice_len[(iep->st >> 4) & 7];
			iep->idx = 0;
		} else if (c >= 0xf0) {
			iep->msg[0] = c;
			iep->len = common_len[c & 7];
			iep->st = c;
			iep->idx = 1;
		} else if (c >= 0x80) {
			iep->msg[0] = c;
			iep->len = voice_len[(c >> 4) & 7];
			iep->last_st = iep->st = c;
			iep->idx = 1;
		} else if (iep->st) {
			if (iep->idx == 0 && iep->st != SYSEX_START)
				iep->msg[iep->idx++] = iep->st;
			iep->msg[iep->idx++] = c;
			if (iep->idx == iep->len) {
				iep->ops->imsg(iep->arg, iep->msg, iep->idx);
				if (iep->st >= 0xf0)
					iep->st = 0;
				iep->idx = 0;
			} else if (iep->idx == MIDI_MSGMAX) {
				/* sysex continued */
				iep->ops->imsg(iep->arg, iep->msg, iep->idx);
				iep->idx = 0;
			}
		}
	}
	iep->tickets -= icount;
	if (iep->tickets < 0)
		iep->tickets = 0;
	midi_tickets(iep);
}

/*
 * store the given message in the output buffer
 */
void
midi_out(struct midi *oep, unsigned char *idata, int icount)
{
	unsigned char *odata;
	int ocount;
#ifdef DEBUG
	int i;
#endif

	while (icount > 0) {
		if (oep->obuf.used == oep->obuf.len) {
#ifdef DEBUG
			if (log_level >= 2) {
				midi_log(oep);
				log_puts(": too slow, discarding ");
				log_putu(oep->obuf.used);
				log_puts(" bytes\n");
			}
#endif
			abuf_rdiscard(&oep->obuf, oep->obuf.used);
			oep->owner = NULL;
			return;
		}
		odata = abuf_wgetblk(&oep->obuf, &ocount);
		if (ocount > icount)
			ocount = icount;
		memcpy(odata, idata, ocount);
#ifdef DEBUG
		if (log_level >= 4) {
			midi_log(oep);
			log_puts(": out: ");
			for (i = 0; i < ocount; i++) {
				log_puts(" ");
				log_putx(odata[i]);
			}
			log_puts("\n");
		}
#endif
		abuf_wcommit(&oep->obuf, ocount);
		icount -= ocount;
		idata += ocount;
	}
}

/*
 * disconnect clients attached to this end-point
 */
void
midi_abort(struct midi *p)
{
	int i;
	struct midi *ep;

	for (i = 0; i < MIDI_NEP; i++) {
		ep = midi_ep + i;
		if ((ep->txmask & p->self) || (p->txmask & ep->self))
			ep->ops->exit(ep->arg);
	}
}

/*
 * connect to "nep" all endpoints currently connected to "oep"
 */
void
midi_migrate(struct midi *oep, struct midi *nep)
{
	struct midithru *t;
	struct midi *ep;
	int i;

	for (i = 0; i < MIDITHRU_NMAX; i++) {
		t = midithru + i;
		if (t->txmask & oep->self) {
			t->txmask &= ~oep->self;
			t->txmask |= nep->self;
		}
		if (t->rxmask & oep->self) {
			t->rxmask &= ~oep->self;
			t->rxmask |= nep->self;
		}
	}

	for (i = 0; i < MIDI_NEP; i++) {
		ep = midi_ep + i;
		if (ep->txmask & oep->self) {
			ep->txmask &= ~oep->self;
			ep->txmask |= nep->self;
		}
	}

	for (i = 0; i < MIDI_NEP; i++) {
		ep = midi_ep + i;
		if (oep->txmask & ep->self) {
			oep->txmask &= ~ep->self;
			nep->txmask |= ep->self;
		}
	}
}

void
port_log(struct port *p)
{
	midi_log(p->midi);
}

void
port_imsg(void *arg, unsigned char *msg, int size)
{
	struct port *p = arg;

	midi_send(p->midi, msg, size);
}


void
port_omsg(void *arg, unsigned char *msg, int size)
{
	struct port *p = arg;

	midi_out(p->midi, msg, size);
}

void
port_fill(void *arg, int count)
{
	/* no flow control */
}

void
port_exit(void *arg)
{
#ifdef DEBUG
	struct port *p = arg;

	if (log_level >= 3) {
		port_log(p);
		log_puts(": port exit\n");
		panic();
	}
#endif
}

/*
 * create a new midi port
 */
struct port *
port_new(char *path, unsigned int mode, int hold)
{
	struct port *c;

	c = xmalloc(sizeof(struct port));
	c->path = path;
	c->state = PORT_CFG;
	c->hold = hold;
	c->midi = midi_new(&port_midiops, c, mode);
	c->num = midi_portnum++;
	c->alt_next = c;
	c->next = port_list;
	port_list = c;
	return c;
}

/*
 * destroy the given midi port
 */
void
port_del(struct port *c)
{
	struct port **p;

	if (c->state != PORT_CFG)
		port_close(c);
	midi_del(c->midi);
	for (p = &port_list; *p != c; p = &(*p)->next) {
#ifdef DEBUG
		if (*p == NULL) {
			log_puts("port to delete not on list\n");
			panic();
		}
#endif
	}
	*p = c->next;
	xfree(c);
}

int
port_ref(struct port *c)
{
#ifdef DEBUG
	if (log_level >= 3) {
		port_log(c);
		log_puts(": port requested\n");
	}
#endif
	if (c->state == PORT_CFG && !port_open(c))
		return 0;
	return 1;
}

void
port_unref(struct port *c)
{
	int i, rxmask;

#ifdef DEBUG
	if (log_level >= 3) {
		port_log(c);
		log_puts(": port released\n");
	}
#endif
	for (rxmask = 0, i = 0; i < MIDI_NEP; i++)
		rxmask |= midi_ep[i].txmask;
	if ((rxmask & c->midi->self) == 0 && c->midi->txmask == 0 &&
	    c->state == PORT_INIT && !c->hold)
		port_drain(c);
}

struct port *
port_alt_ref(int num)
{
	struct port *a, *p;

	a = port_bynum(num);
	if (a == NULL)
		return NULL;

	/* circulate to first alt port */
	while (a->alt_next->num > a->num)
		a = a->alt_next;

	p = a;
	while (1) {
		if (port_ref(p))
			break;
		p = p->alt_next;
		if (p == a)
			return NULL;
	}

	return p;
}

struct port *
port_migrate(struct port *op)
{
	struct port *np;

	/* not opened */
	if (op->state == PORT_CFG)
		return op;

	np = op;
	while (1) {
		/* try next one, circulating through the list */
		np = np->alt_next;
		if (np == op) {
			if (log_level >= 2) {
				port_log(op);
				log_puts(": no fall-back port found\n");
			}
			return op;
		}

		if (port_ref(np))
			break;
	}

	if (log_level >= 2) {
		port_log(op);
		log_puts(": switching to ");
		port_log(np);
		log_puts("\n");
	}

	midi_migrate(op->midi, np->midi);
	return np;
}

struct port *
port_bynum(int num)
{
	struct port *p;

	for (p = port_list; p != NULL; p = p->next) {
		if (p->num == num)
			return p;
	}
	return NULL;
}

int
port_open(struct port *c)
{
	if (!port_mio_open(c)) {
		if (log_level >= 1) {
			port_log(c);
			log_puts(": failed to open midi port\n");
		}
		return 0;
	}
	c->state = PORT_INIT;
	return 1;
}

int
port_close(struct port *c)
{
#ifdef DEBUG
	if (c->state == PORT_CFG) {
		port_log(c);
		log_puts(": can't close port (not opened)\n");
		panic();
	}
#endif
	port_log(c);
	log_puts(": closed\n");
	c->state = PORT_CFG;
	port_mio_close(c);
	return 1;
}

void
port_drain(struct port *c)
{
	struct midi *ep = c->midi;

	if (!(ep->mode & MODE_MIDIOUT) || ep->obuf.used == 0)
		port_close(c);
	else {
		c->state = PORT_DRAIN;
#ifdef DEBUG
		if (log_level >= 3) {
			port_log(c);
			log_puts(": draining\n");
		}
#endif
	}
}

int
port_init(struct port *c)
{
	if (c->hold)
		return port_open(c);
	return 1;
}

void
port_done(struct port *c)
{
	if (c->state == PORT_INIT)
		port_drain(c);
}