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Up to [local] / src / usr.bin / aucat

allow aucat to run as server in play-only and record-only mode, so
it can be used on play-only, record-only and half-duplex devices.
ok jakemsr

/*	$OpenBSD: sock.c,v 1.8 2008/11/17 07:04:13 ratchov Exp $	*/
/*
 * Copyright (c) 2008 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.
 */
/*
 * TODO:
 *
 *	change f->bufsz to contain only socket-side buffer,
 *	because it's less error prone
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "aproc.h"
#include "abuf.h"
#include "sock.h"
#include "dev.h"
#include "conf.h"

int sock_attach(struct sock *, int);
int sock_read(struct sock *);
int sock_write(struct sock *);
int sock_execmsg(struct sock *);
void sock_reset(struct sock *);

struct fileops sock_ops = {
	"sock",
	sizeof(struct sock),
       	pipe_close,
	pipe_read,
	pipe_write,
	NULL, /* start */
	NULL, /* stop */
	pipe_nfds,
	pipe_pollfd,
	pipe_revents
};

void
rsock_done(struct aproc *p)
{
	struct sock *f = (struct sock *)p->u.io.file;

	DPRINTFN(1, "rsock_done: %p\n", f);
	sock_reset(f);
	f->pipe.file.rproc = NULL;
	if (f->pipe.file.wproc) {
		aproc_del(f->pipe.file.wproc);
		file_del(&f->pipe.file);
	}
}

int
rsock_in(struct aproc *p, struct abuf *ibuf_dummy)
{
	struct sock *f = (struct sock *)p->u.io.file;
	struct abuf *obuf;

	DPRINTFN(4, "rsock_in: %p\n", f);

	if (!sock_read(f))
		return 0;
	obuf = LIST_FIRST(&p->obuflist);
	if (obuf) {
		if (!abuf_flush(obuf))
			return 0;
	}
	return 1;
}

int
rsock_out(struct aproc *p, struct abuf *obuf)
{
	struct sock *f = (struct sock *)p->u.io.file;

	if (f->pipe.file.refs > 0)
		return 0;

	DPRINTFN(4, "rsock_out: %p\n", f);

	/* 
	 * when calling sock_read(), we may receive a ``STOP'' command,
	 * and detach ``obuf''. In this case, there's no more caller and
	 * we'll stop processing further messages, resulting in a dead lock.
	 * The solution is to iterate over sock_read() in order to
	 * consume all messages().
	 */
	for (;;) {
		if (!sock_read(f))
			return 0;		
	}
	return 1;
}

void
rsock_eof(struct aproc *p, struct abuf *ibuf_dummy)
{
	DPRINTFN(3, "rsock_eof: %p\n", p->u.io.file);
	aproc_del(p);
}

void
rsock_hup(struct aproc *p, struct abuf *ibuf)
{
	DPRINTFN(3, "rsock_hup: %p\n", p->u.io.file);
	aproc_del(p);
}

void
rsock_opos(struct aproc *p, struct abuf *obuf, int delta)
{
	struct sock *f = (struct sock *)p->u.io.file;

	f->odelta += delta;
	DPRINTFN(3, "rsock_opos: %p: delta = %d, odelta = %d\n",
	    f, delta, f->odelta);

	/*
	 * negative deltas are xrun notifications for internal uses
	 * only. Dont generate a packet for this, the client will be
	 * notified later.
	 */
	if (delta <= 0)
		return;
	for (;;) {
		if (!sock_write(f))
			break;
	}
}

struct aproc_ops rsock_ops = {
	"rsock",
	rsock_in,
	rsock_out,
	rsock_eof,
	rsock_hup,
	NULL, /* newin */
	NULL, /* newout */
	NULL, /* ipos */
	rsock_opos,
	rsock_done
};

void
wsock_done(struct aproc *p)
{
	struct sock *f = (struct sock *)p->u.io.file;

	DPRINTFN(1, "wsock_done: %p\n", f);
	sock_reset(f);
	f->pipe.file.wproc = NULL;
	if (f->pipe.file.rproc) {
		aproc_del(f->pipe.file.rproc);
		file_del(&f->pipe.file);
	}
}

int
wsock_in(struct aproc *p, struct abuf *ibuf)
{
	struct sock *f = (struct sock *)p->u.io.file;

	if (f->pipe.file.refs > 0)
		return 0;

	DPRINTFN(4, "wsock_in: %p\n", f);

	/*
	 * see remark in rsock_out()
	 */
	for (;;) {
		if (!sock_write(f))
			return 0;
	}
	return 1;
}

int
wsock_out(struct aproc *p, struct abuf *obuf_dummy)
{
	struct abuf *ibuf = LIST_FIRST(&p->ibuflist);
	struct sock *f = (struct sock *)p->u.io.file;

	DPRINTFN(3, "wsock_out: %p\n", f);

	if (ibuf) {
		DPRINTFN(3, "wsock_out: %p, filling ibuf\n", f);
		if (!abuf_fill(ibuf))
			return 0;
	}
	if (!sock_write(f))
		return 0;
	return 1;
}

void
wsock_eof(struct aproc *p, struct abuf *obuf)
{
	DPRINTFN(3, "wsock_eof: %p\n", p->u.io.file);
	aproc_del(p);
}

void
wsock_hup(struct aproc *p, struct abuf *obuf_dummy)
{
	DPRINTFN(3, "wsock_hup: %p\n", p->u.io.file);
	aproc_del(p);
}

void
wsock_ipos(struct aproc *p, struct abuf *obuf, int delta)
{
	struct sock *f = (struct sock *)p->u.io.file;

	f->idelta += delta;
	DPRINTFN(3, "wsock_ipos: %p, delta = %d, odelta = %d\n",
	    f, delta, f->idelta);

	/*
	 * negative deltas are xrun notifications for internal uses
	 * only. Dont generate a packet for this, the client will be
	 * notified later.
	 */
	if (delta <= 0)
		return;
	for (;;) {
		if (!sock_write(f))
			break;
	}
}

struct aproc_ops wsock_ops = {
	"wsock",
	wsock_in,
	wsock_out,
	wsock_eof,
	wsock_hup,
	NULL, /* newin */
	NULL, /* newout */
	wsock_ipos,
	NULL, /* opos */
	wsock_done
};

/*
 * initialise socket in the SOCK_INIT state with default
 * parameters
 */
struct sock *
sock_new(struct fileops *ops, int fd, char *name,
    struct aparams *wpar, struct aparams *rpar, int maxweight)
{
	struct aproc *rproc, *wproc;
	struct sock *f;

	f = (struct sock *)pipe_new(ops, fd, name);
	f->pstate = SOCK_INIT;
	f->mode = 0;
	if (dev_rec) {
		f->templ_wpar = *wpar;
		f->wpar = f->templ_wpar;
		f->mode |= AMSG_REC;
	}
	if (dev_play) {
		f->templ_rpar = *rpar;
		f->rpar = f->templ_rpar;
		f->mode |= AMSG_PLAY;
	}
	f->xrun = AMSG_IGNORE;
	f->bufsz = 2 * dev_bufsz;
	f->round = dev_round;
	f->odelta = f->idelta = 0;
	f->maxweight = maxweight;
	f->vol = ADATA_UNIT;

	wproc = aproc_new(&wsock_ops, name);
	wproc->u.io.file = &f->pipe.file;
	f->pipe.file.wproc = wproc;
	f->wstate = SOCK_WIDLE;
	f->wtodo = 0xdeadbeef;

	rproc = aproc_new(&rsock_ops, name);
	rproc->u.io.file = &f->pipe.file;
	f->pipe.file.rproc = rproc;
	f->rstate = SOCK_RMSG;
	f->rtodo = sizeof(struct amsg);
	return f;
}

/*
 * free buffers
 */
void
sock_freebuf(struct sock *f)
{
	struct abuf *rbuf, *wbuf;
	
	f->pstate = SOCK_INIT;
	DPRINTF("sock_freebuf:\n");
	rbuf = LIST_FIRST(&f->pipe.file.rproc->obuflist);
	if (rbuf)
		abuf_eof(rbuf);
	wbuf = LIST_FIRST(&f->pipe.file.wproc->ibuflist);
	if (wbuf)
		abuf_hup(wbuf);
}

/*
 * allocate buffers, so client can start filling write-end.
 */
void
sock_allocbuf(struct sock *f)
{
	struct abuf *rbuf = NULL, *wbuf = NULL;
	unsigned nfr = 0;

	if (f->mode & AMSG_PLAY) {
		nfr = f->bufsz - dev_bufsz * f->rpar.rate / dev_rate;
		rbuf = abuf_new(nfr, &f->rpar);
		aproc_setout(f->pipe.file.rproc, rbuf);
		f->odelta = 0;
	}
	if (f->mode & AMSG_REC) {
		nfr = f->bufsz - dev_bufsz * f->wpar.rate / dev_rate;
		wbuf = abuf_new(nfr, &f->wpar);
		aproc_setin(f->pipe.file.wproc, wbuf);
		f->idelta = 0;
	}

	DPRINTF("sock_allocbuf: %p, using %u/%u frames buffer\n",
	    f, nfr, f->bufsz);

	f->pstate = SOCK_START;
	if (!(f->mode & AMSG_PLAY))
		(void)sock_attach(f, 0);
}

/*
 * free buffers
 */
void
sock_setvol(struct sock *f, int vol)
{
	struct abuf *rbuf;
	
	f->vol = vol;
	rbuf = LIST_FIRST(&f->pipe.file.rproc->obuflist);	
	if (!rbuf) {
		DPRINTF("sock_setvol: no read buffer yet\n");
		return;
	}
	dev_setvol(rbuf, vol);
}

/*
 * attach play and/or record buffers to dev_mix and/or dev_sub
 */
int
sock_attach(struct sock *f, int force)
{
	struct abuf *rbuf, *wbuf;

	rbuf = LIST_FIRST(&f->pipe.file.rproc->obuflist);
	wbuf = LIST_FIRST(&f->pipe.file.wproc->ibuflist);

	/*
	 * if in SOCK_START state, dont attach until
	 * the buffer isn't completely filled
	 */
	if (!force && rbuf && ABUF_WOK(rbuf))
		return 0;
	
	DPRINTF("sock_attach: %p\n", f);
	f->pstate = SOCK_RUN;

	/*
	 * attach them to the device
	 */
	dev_attach(f->pipe.file.name,
	    (f->mode & AMSG_PLAY) ? rbuf : NULL, &f->rpar, f->xrun,
	    (f->mode & AMSG_REC)  ? wbuf : NULL, &f->wpar, f->xrun,
	    f->maxweight);
	if (f->mode & AMSG_PLAY)
		dev_setvol(rbuf, f->vol);

	/*
	 * send the initial position, if needed
	 */
	for (;;) {
		if (!sock_write(f))
			break;
	}
	return 1;
}

void
sock_reset(struct sock *f)
{
	switch (f->pstate) {
	case SOCK_START:
		(void)sock_attach(f, 1);
		f->pstate = SOCK_RUN;
		/* PASSTHROUGH */
	case SOCK_RUN:
		sock_freebuf(f);
		f->pstate = SOCK_INIT;
		/* PASSTHROUGH */
	case SOCK_INIT:
		/* nothing yet */
		break;
	}
}

/*
 * read a message from the file descriptor, return 1 if done, 0
 * otherwise. The message is stored in f->rmsg
 */
int
sock_rmsg(struct sock *f)
{
	unsigned count;
	unsigned char *data;

	while (f->rtodo > 0) {
		if (!(f->pipe.file.state & FILE_ROK)) {
			DPRINTFN(4, "sock_rmsg: blk, rtodo = %u\n", f->rtodo);
			return 0;
		}
		data = (unsigned char *)&f->rmsg;
		data += sizeof(struct amsg) - f->rtodo;
		count = file_read(&f->pipe.file, data, f->rtodo);
		if (count == 0)
			return 0;
		f->rtodo -= count;
	}
	DPRINTFN(4, "sock_rmsg: %p: done\n", f);
	return 1;
}

/*
 * write a message to the file descriptor, return 1 if done, 0
 * otherwise.  The "m" argument is f->rmsg or f->wmsg, and the "ptodo"
 * points to the f->rtodo or f->wtodo respectively.
 */
int
sock_wmsg(struct sock *f, struct amsg *m, unsigned *ptodo)
{
	unsigned count;
	unsigned char *data;

	while (*ptodo > 0) {
		if (!(f->pipe.file.state & FILE_WOK)) {
			DPRINTFN(4, "sock_wmsg: blk, *ptodo = %u\n", *ptodo);
			return 0;
		}
		data = (unsigned char *)m;
		data += sizeof(struct amsg) - *ptodo;
		count = file_write(&f->pipe.file, data, *ptodo);
		if (count == 0)
			return 0;
		*ptodo -= count;
	}
	DPRINTFN(4, "sock_wmsg: %p: done\n", f);
	return 1;
}

/*
 * read data chunk from the file descriptor, return 1 if at least one
 * byte was read, 0 if the file blocked.
 */
int
sock_rdata(struct sock *f)
{
	struct aproc *p;
	struct abuf *obuf;
	unsigned char *data;
	unsigned count, n;

#ifdef DEBUG
	if (f->rtodo == 0) {
		fprintf(stderr, "sock_rdata: bad call: zero arg\n");
		abort();
	}
#endif
	p = f->pipe.file.rproc;
	obuf = LIST_FIRST(&p->obuflist);
	if (ABUF_FULL(obuf) || !(f->pipe.file.state & FILE_ROK))
		return 0;
	data = abuf_wgetblk(obuf, &count, 0);
	if (count > f->rtodo)
		count = f->rtodo;
	n = file_read(&f->pipe.file, data, count);
	if (n == 0)
		return 0;
	abuf_wcommit(obuf, n);
	f->rtodo -= n;
	return 1;
}

/*
 * write data chunk to the file descriptor, return 1 if at least one
 * byte was written, 0 if the file blocked.
 */
int
sock_wdata(struct sock *f)
{
	struct aproc *p;
	struct abuf *ibuf;
	unsigned char *data;
	unsigned count, n;
#define ZERO_MAX 0x1000
	static char zero[ZERO_MAX];

#ifdef DEBUG
	if (f->wtodo == 0) {
		fprintf(stderr, "sock_wdata: bad call: zero arg\n");
		abort();
	}
#endif
	if (!(f->pipe.file.state & FILE_WOK))
		return 0;
	p = f->pipe.file.wproc;
	ibuf = LIST_FIRST(&p->ibuflist);
	if (ibuf) {
		if (ABUF_EMPTY(ibuf))
			return 0;
		data = abuf_rgetblk(ibuf, &count, 0);
		if (count > f->wtodo)
			count = f->wtodo;
		n = file_write(&f->pipe.file, data, count);
		if (n == 0)
			return 0;
		abuf_rdiscard(ibuf, n);
		f->wtodo -= n;
	} else {
		/*
		 * there's no dev_detach() routine yet,
		 * so now we abruptly destroy the buffer.
		 * Until we implement dev_detach, complete
		 * the packet with zeros...
		 */
		count = ZERO_MAX;
		if (count > f->wtodo)
			count = f->wtodo;
		n = file_write(&f->pipe.file, zero, count);
		if (n == 0)
			return 0;
		f->wtodo -= n;
	}		
	return 1;
}

int
sock_setpar(struct sock *f)
{
	struct amsg_par *p = &f->rmsg.u.par;
	unsigned minbuf, maxbuf;
	
	if (AMSG_ISSET(p->mode)) {
		if ((p->mode & ~(AMSG_PLAY | AMSG_REC)) || p->mode == 0) {
			DPRINTF("sock_setpar: bad mode %x\n", p->mode);
			return 0;
		}
		f->mode = 0;
		if ((p->mode & AMSG_PLAY) && dev_mix)
			f->mode |= AMSG_PLAY;
		if ((p->mode & AMSG_REC) && dev_sub)
			f->mode |= AMSG_REC;
		DPRINTF("sock_setpar: mode -> %x\n", f->mode);
	}
	if (AMSG_ISSET(p->bits)) {
		if (p->bits < BITS_MIN || p->bits > BITS_MAX) {
			DPRINTF("sock_setpar: bits out of bounds\n");
			return 0;
		}
		if (AMSG_ISSET(p->bps)) {
			if (p->bps < ((p->bits + 7) / 8) || p->bps > 4) {
				DPRINTF("sock_setpar: bps out of bounds\n");
				return 0;
			}
		} else
			p->bps = APARAMS_BPS(p->bits);
		f->rpar.bits = f->wpar.bits = p->bits;
		f->rpar.bps = f->wpar.bps = p->bps;
		DPRINTF("sock_setpar: bits/bps -> %u/%u\n", p->bits, p->bps);
	}
	if (AMSG_ISSET(p->sig))
		f->rpar.sig = f->wpar.sig = p->sig ? 1 : 0;
	if (AMSG_ISSET(p->le))
		f->rpar.le = f->wpar.le = p->le ? 1 : 0;
	if (AMSG_ISSET(p->msb))
		f->rpar.msb = f->wpar.msb = p->msb ? 1 : 0;
	if (AMSG_ISSET(p->rchan) && (f->mode & AMSG_REC)) {
		if (p->rchan < 1)
			p->rchan = 1;
		if (p->rchan > NCHAN_MAX)
			p->rchan = NCHAN_MAX;
		f->wpar.cmin = f->templ_wpar.cmin;
		f->wpar.cmax = f->templ_wpar.cmin + p->rchan - 1;
		if (f->wpar.cmax > f->templ_wpar.cmax)
			f->wpar.cmax = f->templ_wpar.cmax;
		DPRINTF("sock_setpar: rchan -> %u:%u\n",
		    f->wpar.cmin, f->wpar.cmax);
	}
	if (AMSG_ISSET(p->pchan) && (f->mode & AMSG_PLAY)) {
		if (p->pchan < 1)
			p->pchan = 1;
		if (p->pchan > NCHAN_MAX)
			p->pchan = NCHAN_MAX;
		f->rpar.cmin = f->templ_rpar.cmin;
		f->rpar.cmax = f->templ_rpar.cmin + p->pchan - 1;
		if (f->rpar.cmax > f->templ_rpar.cmax)
			f->rpar.cmax = f->templ_rpar.cmax;
		DPRINTF("sock_setpar: pchan -> %u:%u\n",
		    f->rpar.cmin, f->rpar.cmax);
	}
	if (AMSG_ISSET(p->rate)) {
		if (p->rate < RATE_MIN)
			p->rate = RATE_MIN;
		if (p->rate > RATE_MAX)
			p->rate = RATE_MAX;
		dev_roundrate(&p->rate, &f->round);
		f->rpar.rate = f->wpar.rate = p->rate;
		if (f->mode & AMSG_PLAY)
			f->bufsz = 2 * dev_bufsz * f->rpar.rate / dev_rate;
		else
			f->bufsz = 2 * dev_bufsz * f->wpar.rate / dev_rate;
		DPRINTF("sock_setpar: rate -> %u\n", p->rate);
	}
	if (AMSG_ISSET(p->xrun)) {
		if (p->xrun != AMSG_IGNORE &&
		    p->xrun != AMSG_SYNC &&
		    p->xrun != AMSG_ERROR) {
			DPRINTF("sock_setpar: bad xrun: %u\n", p->xrun);
			return 0;
		}
		f->xrun = p->xrun;
		DPRINTF("sock_setpar: xrun -> %u\n", f->xrun);
	}
	if (AMSG_ISSET(p->bufsz)) {
		minbuf = 3 * dev_bufsz / 2;
		minbuf -= minbuf % dev_round;
		maxbuf = dev_bufsz;
		if (f->mode & AMSG_PLAY) {
			minbuf = minbuf * f->rpar.rate / dev_rate;
			maxbuf = maxbuf * f->rpar.rate / dev_rate;
			maxbuf += f->rpar.rate;
		} else {
			minbuf = minbuf * f->wpar.rate / dev_rate;
			maxbuf = maxbuf * f->wpar.rate / dev_rate;
			maxbuf += f->wpar.rate;
		}
		if (p->bufsz < minbuf)
			p->bufsz = minbuf;
		if (p->bufsz > maxbuf)
			p->bufsz = maxbuf;
		f->bufsz = p->bufsz + f->round - 1;
		f->bufsz -= f->bufsz % f->round;
		DPRINTF("sock_setpar: bufsz -> %u\n", f->bufsz);
	}
#ifdef DEBUG
	if (debug_level > 0) {
		fprintf(stderr, "sock_setpar: %p: rpar=", f);
		aparams_print(&f->rpar);
		fprintf(stderr, ", wpar=");
		aparams_print(&f->wpar);
		fprintf(stderr, ", mode=%u, bufsz=%u\n", f->mode, f->bufsz);
	}
#endif
	return 1;
}

/*
 * execute message in f->rmsg and change the state accordingly; return 1
 * on success, and 0 on failure, in which case the socket is destroyed.
 */
int
sock_execmsg(struct sock *f)
{
	struct amsg *m = &f->rmsg;

	switch (m->cmd) {
	case AMSG_DATA:
		DPRINTFN(4, "sock_execmsg: %p: DATA\n", f);
		if (f->pstate != SOCK_RUN && f->pstate != SOCK_START) {
			DPRINTF("sock_execmsg: %p: DATA, bad state\n", f);
			aproc_del(f->pipe.file.rproc);
			return 0;
		}
		if (!(f->mode & AMSG_PLAY)) {
			DPRINTF("sock_execmsg: %p: DATA, not allowed\n", f);
			aproc_del(f->pipe.file.rproc);
			return 0;
		}
		f->rstate = SOCK_RDATA;
		f->rtodo = m->u.data.size;
		if (f->rtodo == 0) {
			DPRINTF("sock_execmsg: zero-length data chunk\n");
			aproc_del(f->pipe.file.rproc);
			return 0;
		}
		break;
	case AMSG_START:
		DPRINTFN(2, "sock_execmsg: %p: START\n", f);
		if (f->pstate != SOCK_INIT) {
			DPRINTF("sock_execmsg: %p: START, bad state\n", f);
			aproc_del(f->pipe.file.rproc);
			return 0;
		}
		sock_allocbuf(f);
		f->rstate = SOCK_RMSG;
		f->rtodo = sizeof(struct amsg);
		break;
	case AMSG_STOP:
		DPRINTFN(2, "sock_execmsg: %p: STOP\n", f);
		if (f->pstate != SOCK_RUN && f->pstate != SOCK_START) {
			DPRINTF("sock_execmsg: %p: STOP, bad state\n", f);
			aproc_del(f->pipe.file.rproc);
			return 0;
		}
		if (f->pstate == SOCK_START)
			(void)sock_attach(f, 1);
		sock_freebuf(f);
		AMSG_INIT(m);
		m->cmd = AMSG_ACK;
		f->rstate = SOCK_RRET;
		f->rtodo = sizeof(struct amsg);
		break;
	case AMSG_SETPAR:
		DPRINTFN(2, "sock_execmsg: %p: SETPAR\n", f);
		if (f->pstate != SOCK_INIT) {
			DPRINTF("sock_execmsg: %p: SETPAR, bad state\n", f);
			aproc_del(f->pipe.file.rproc);
			return 0;
		}
		if (!sock_setpar(f)) {
			aproc_del(f->pipe.file.rproc);
			return 0;
		}
		f->rtodo = sizeof(struct amsg);
		f->rstate = SOCK_RMSG;
		break;
	case AMSG_GETPAR:
		DPRINTFN(2, "sock_execmsg: %p: GETPAR\n", f);
		if (f->pstate != SOCK_INIT) {
			DPRINTF("sock_execmsg: %p: GETPAR, bad state\n", f);
			aproc_del(f->pipe.file.rproc);
			return 0;
		}
		AMSG_INIT(m);
		m->cmd = AMSG_GETPAR;
		m->u.par.mode = f->mode;
		m->u.par.bits = f->rpar.bits;
		m->u.par.bps = f->rpar.bps;
		m->u.par.sig = f->rpar.sig;
		m->u.par.le = f->rpar.le;
		m->u.par.msb = f->rpar.msb;
		m->u.par.rate = f->rpar.rate;
		m->u.par.rchan = f->wpar.cmax - f->wpar.cmin + 1;
		m->u.par.pchan = f->rpar.cmax - f->rpar.cmin + 1;
		m->u.par.bufsz = f->bufsz;
		m->u.par.round = f->round;
		f->rstate = SOCK_RRET;
		f->rtodo = sizeof(struct amsg);
		break;
	case AMSG_GETCAP:
		DPRINTFN(2, "sock_execmsg: %p: GETCAP\n", f);
		if (f->pstate != SOCK_INIT) {
			DPRINTF("sock_execmsg: %p: GETCAP, bad state\n", f);
			aproc_del(f->pipe.file.rproc);
			return 0;
		}
		AMSG_INIT(m);
		m->cmd = AMSG_GETCAP;
		m->u.cap.rate = dev_rate;
		m->u.cap.rate_div = dev_rate_div;
		m->u.cap.pchan = dev_mix ?
		    (f->templ_rpar.cmax - f->templ_rpar.cmin + 1) : 0;
		m->u.cap.rchan = dev_sub ?
		    (f->templ_wpar.cmax - f->templ_wpar.cmin + 1) : 0;
		m->u.cap.bits = sizeof(short) * 8;
		m->u.cap.bps = sizeof(short);
		f->rstate = SOCK_RRET;
		f->rtodo = sizeof(struct amsg);
		break;
	case AMSG_SETVOL:
		DPRINTFN(2, "sock_execmsg: %p: SETVOL\n", f);
		if (f->pstate != SOCK_RUN &&
		    f->pstate != SOCK_START && f->pstate != SOCK_INIT) {
			DPRINTF("sock_execmsg: %p: SETVOL, bad state\n", f);
			aproc_del(f->pipe.file.rproc);
			return 0;
		}
		if (m->u.vol.ctl > MIDI_MAXCTL) {
			DPRINTF("sock_execmsg: %p: SETVOL, out of range\n", f);
			aproc_del(f->pipe.file.rproc);
			return 0;
		}
		DPRINTF("sock_execmsg: SETVOL %u\n", m->u.vol.ctl);
		sock_setvol(f, MIDI_TO_ADATA(m->u.vol.ctl));
		f->rtodo = sizeof(struct amsg);
		f->rstate = SOCK_RMSG;
		break;
	default:
		DPRINTF("sock_execmsg: %p bogus command\n", f);
		aproc_del(f->pipe.file.rproc);
		return 0;
	}
	if (f->rstate == SOCK_RRET) {
		if (f->wstate != SOCK_WIDLE ||
		    !sock_wmsg(f, &f->rmsg, &f->rtodo))
			return 0;
		DPRINTF("sock_execmsg: %p RRET done\n", f);
		f->rtodo = sizeof(struct amsg);
		f->rstate = SOCK_RMSG;
	}
	return 1;
}

/*
 * create a new data/pos message
 */
int
sock_buildmsg(struct sock *f)
{
	struct aproc *p;
	struct abuf *ibuf;
	int *pdelta;
	
	/*
	 * if pos changed, build a MOVE message
	 */
	pdelta = (f->mode & AMSG_REC) ? &f->idelta : &f->odelta;
	if ((f->pstate == SOCK_RUN && *pdelta > 0) ||
	    (f->pstate == SOCK_START && *pdelta < 0)) {
		DPRINTFN(4, "sock_buildmsg: %p: POS: %d\n", f, *pdelta);
		AMSG_INIT(&f->wmsg);
		f->wmsg.cmd = AMSG_MOVE;
		f->wmsg.u.ts.delta = *pdelta;
		*pdelta = 0;
		f->wtodo = sizeof(struct amsg);
		f->wstate = SOCK_WMSG;
		return 1;
	}

	/*
	 * if data available, build a DATA message
	 */
	p = f->pipe.file.wproc;
	ibuf = LIST_FIRST(&p->ibuflist);
	if (ibuf && ABUF_ROK(ibuf)) {
		AMSG_INIT(&f->wmsg);
		f->wmsg.cmd = AMSG_DATA;
		f->wmsg.u.data.size = ibuf->used - (ibuf->used % ibuf->bpf);
		if (f->wmsg.u.data.size > AMSG_DATAMAX)
			f->wmsg.u.data.size =
			    AMSG_DATAMAX - (AMSG_DATAMAX % ibuf->bpf);
		f->wtodo = sizeof(struct amsg);
		f->wstate = SOCK_WMSG;
		return 1;
	}

	DPRINTFN(4, "sock_buildmsg: %p: idling...\n", f);
	f->wstate = SOCK_WIDLE;
	return 0;
}

/*
 * read from the socket file descriptor, fill input buffer and update
 * the state. Return 1 if at least one message or 1 data byte was
 * processed, 0 if something blocked.
 */
int
sock_read(struct sock *f)
{
	DPRINTFN(4, "sock_read: %p; rstate = %u, rtodo = %u\n",
	    f, f->rstate, f->rtodo);

	switch (f->rstate) {
	case SOCK_RMSG:
		if (!sock_rmsg(f))
			return 0;
		if (!sock_execmsg(f))
			return 0;
		break;
	case SOCK_RDATA:
		if (!sock_rdata(f))
			return 0;
		if (f->rtodo == 0) {
			f->rstate = SOCK_RMSG;
			f->rtodo = sizeof(struct amsg);
		}
		if (f->pstate == SOCK_START)
			(void)sock_attach(f, 0);
		break;
	case SOCK_RRET:
		DPRINTF("sock_read: %p: blocked in RRET\n", f);
		return 0;
	}
	DPRINTFN(4, "sock_read: %p: done, rstate = %u\n", f, f->rstate);
	return 1;
}

/*
 * process messages to return
 */
int
sock_return(struct sock *f)
{
	struct aproc *rp;

	while (f->rstate == SOCK_RRET) {
		if (!sock_wmsg(f, &f->rmsg, &f->rtodo))
			return 0;
		DPRINTF("sock_return: %p: done\n", f);
		f->rstate = SOCK_RMSG;
		f->rtodo = sizeof(struct amsg);
		for (;;) {
			/*
			 * in() may trigger rsock_done and destroy the
			 * wsock
			 */
			rp = f->pipe.file.rproc;
			if (!rp || !rp->ops->in(rp, NULL))
				break;
		}
		if (f->pipe.file.wproc == NULL)
			return 0;
	}
	return 1;
}

/*
 * write messages and data on the socket file descriptor. Return 1 if
 * at least one message or one data byte was processed, 0 if something
 * blocked.
 */
int
sock_write(struct sock *f)
{
	DPRINTFN(4, "sock_write: %p: wstate = %u, wtodo = %u\n",
	    f, f->wstate, f->wtodo);

	switch (f->wstate) {
	case SOCK_WMSG:
		if (!sock_wmsg(f, &f->wmsg, &f->wtodo))
			return 0;
		if (f->wmsg.cmd != AMSG_DATA) {
			f->wstate = SOCK_WIDLE;
			f->wtodo = 0xdeadbeef;
			break;
		}
		f->wstate = SOCK_WDATA;
		f->wtodo = f->wmsg.u.data.size;
		/* PASSTHROUGH */
	case SOCK_WDATA:
		if (!sock_wdata(f))
			return 0;
		if (f->wtodo > 0)
			break;
		f->wstate = SOCK_WIDLE;
		f->wtodo = 0xdeadbeef;
		/* PASSTHROUGH */
	case SOCK_WIDLE:
		if (!sock_return(f))
			return 0;
		if (!sock_buildmsg(f))
			return 0;
		break;
	default:
		fprintf(stderr, "sock_write: unknown state\n");
		abort();
	}
	return 1;
}