/*-
 * Copyright (c) 2005-2009 Ariff Abdullah <ariff@FreeBSD.org>
 * Copyright (c) 2001 Cameron Grant <cg@FreeBSD.org>
 * 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, 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.
 */

#ifdef HAVE_KERNEL_OPTION_HEADERS
#include "opt_snd.h"
#endif

#include <dev/sound/pcm/sound.h>
#include <dev/sound/pcm/pcm.h>
#include <dev/sound/version.h>
#include <sys/device.h>

SND_DECLARE_FILE("$FreeBSD: head/sys/dev/sound/pcm/sndstat.c 248381 2013-03-16 17:57:00Z joel $");

#define	SS_TYPE_MODULE		0
#define	SS_TYPE_FIRST		1
#define	SS_TYPE_PCM		1
#define	SS_TYPE_MIDI		2
#define	SS_TYPE_SEQUENCER	3
#define	SS_TYPE_LAST		3

static d_open_t sndstat_open;
static d_close_t sndstat_close;
static d_read_t sndstat_read;

static struct dev_ops sndstat_cdevsw = {
	{ "sndstat", 0, D_MPSAFE },
	.d_open =	sndstat_open,
	.d_close =	sndstat_close,
	.d_read =	sndstat_read,
};

struct sndstat_entry {
	SLIST_ENTRY(sndstat_entry) link;
	device_t dev;
	char *str;
	sndstat_handler handler;
	int type, unit;
};

static struct lock sndstat_lock;
static struct sbuf sndstat_sbuf;
static struct cdev *sndstat_dev = NULL;
static int sndstat_buflen = 0;
static int sndstat_maxunit = -1;
static int sndstat_files = 0;

#define SNDSTAT_PID(x)		((pid_t)((intptr_t)((x)->si_drv1)))
#define SNDSTAT_PID_SET(x, y)	(x)->si_drv1 = (void *)((intptr_t)(y))
#define SNDSTAT_FLUSH()		do {					\
	if (sndstat_buflen != -1) {					\
		sbuf_delete(&sndstat_sbuf);				\
		sndstat_buflen = -1;					\
	}								\
} while (0)

static SLIST_HEAD(, sndstat_entry) sndstat_devlist = SLIST_HEAD_INITIALIZER(sndstat_devlist);

int snd_verbose = 0;
TUNABLE_INT("hw.snd.verbose", &snd_verbose);

#ifdef SND_DEBUG
static int
sysctl_hw_snd_sndstat_pid(SYSCTL_HANDLER_ARGS)
{
	int err, val;

	if (sndstat_dev == NULL)
		return (EINVAL);

	lockmgr(&sndstat_lock, LK_EXCLUSIVE);
	val = (int)SNDSTAT_PID(sndstat_dev);
	err = sysctl_handle_int(oidp, &val, 0, req);
	if (err == 0 && req->newptr != NULL && val == 0) {
		SNDSTAT_FLUSH();
		SNDSTAT_PID_SET(sndstat_dev, 0);
	}
	lockmgr(&sndstat_lock, LK_RELEASE);
	return (err);
}
SYSCTL_PROC(_hw_snd, OID_AUTO, sndstat_pid, CTLTYPE_INT | CTLFLAG_RW,
    0, sizeof(int), sysctl_hw_snd_sndstat_pid, "I", "sndstat busy pid");
#endif

static int sndstat_prepare(struct sbuf *s);

static int
sysctl_hw_sndverbose(SYSCTL_HANDLER_ARGS)
{
	int error, verbose;

	verbose = snd_verbose;
	error = sysctl_handle_int(oidp, &verbose, 0, req);
	if (error == 0 && req->newptr != NULL) {
		if (verbose < 0 || verbose > 4)
			error = EINVAL;
		else
			snd_verbose = verbose;
	}
	return error;
}
SYSCTL_PROC(_hw_snd, OID_AUTO, verbose, CTLTYPE_INT | CTLFLAG_RW,
            0, sizeof(int), sysctl_hw_sndverbose, "I", "verbosity level");

static int
sndstat_open(struct dev_open_args *ap)
{
	struct cdev *i_dev = ap->a_head.a_dev;

	if (sndstat_dev == NULL || i_dev != sndstat_dev)
		return EBADF;

	lockmgr(&sndstat_lock, LK_EXCLUSIVE);
	/* Deal with pulseaudio opening /dev/sndstat twice. */
	if (SNDSTAT_PID(i_dev) == curproc->p_pid) {
		/* Nothing */
	} else if (SNDSTAT_PID(i_dev) != 0) {
		lockmgr(&sndstat_lock, LK_RELEASE);
		return EBUSY;
	} else {
		SNDSTAT_PID_SET(i_dev, curproc->p_pid);
		if (sbuf_new(&sndstat_sbuf, NULL, 4096, SBUF_AUTOEXTEND) == NULL) {
			SNDSTAT_PID_SET(i_dev, 0);
			lockmgr(&sndstat_lock, LK_RELEASE);
			return ENXIO;
		}
		sndstat_buflen = 0;
	}
	lockmgr(&sndstat_lock, LK_RELEASE);
	return 0;
}

static int
sndstat_close(struct dev_close_args *ap)
{
	struct cdev *i_dev = ap->a_head.a_dev;

	if (sndstat_dev == NULL || i_dev != sndstat_dev)
		return EBADF;

	lockmgr(&sndstat_lock, LK_EXCLUSIVE);
	if (SNDSTAT_PID(i_dev) == 0) {
		lockmgr(&sndstat_lock, LK_RELEASE);
		return EBADF;
	}

	SNDSTAT_FLUSH();
	SNDSTAT_PID_SET(i_dev, 0);

	lockmgr(&sndstat_lock, LK_RELEASE);

	return 0;
}

static int
sndstat_read(struct dev_read_args *ap)
{
	struct cdev *i_dev = ap->a_head.a_dev;
	struct uio *buf = ap->a_uio;
	int l, err;

	if (sndstat_dev == NULL || i_dev != sndstat_dev)
		return EBADF;

	lockmgr(&sndstat_lock, LK_EXCLUSIVE);
	if (SNDSTAT_PID(i_dev) != buf->uio_td->td_proc->p_pid ||
	    sndstat_buflen == -1) {
		lockmgr(&sndstat_lock, LK_RELEASE);
		return EBADF;
	}

	if (sndstat_buflen == 0) {
		err = (sndstat_prepare(&sndstat_sbuf) > 0) ? 0 : ENOMEM;
		if (err) {
			SNDSTAT_FLUSH();
			lockmgr(&sndstat_lock, LK_RELEASE);
			return err;
		}
		sndstat_buflen = sbuf_len(&sndstat_sbuf);
	}

	l = min(buf->uio_resid, sndstat_buflen - buf->uio_offset);
	err = (l > 0)? uiomove(sbuf_data(&sndstat_sbuf) + buf->uio_offset, l, buf) : 0;
	lockmgr(&sndstat_lock, LK_RELEASE);

	return err;
}

/************************************************************************/

static struct sndstat_entry *
sndstat_find(int type, int unit)
{
	struct sndstat_entry *ent;

	SLIST_FOREACH(ent, &sndstat_devlist, link) {
		if (ent->type == type && ent->unit == unit)
			return ent;
	}

	return NULL;
}

/* XXX profmakx
 * The following two functions are called from
 * pcm_register and pcm_unregister in kernel
 * which means that td_proc of curthread can be NULL
 * because this is called from a kernel thread.
 * We handle this as a separate case for the time
 * being.
 *
 * Should the kernel be able to override ownership of sndstat?
 */

int
sndstat_acquire(struct thread *td)
{
	if (sndstat_dev == NULL)
		return EBADF;

	lockmgr(&sndstat_lock, LK_EXCLUSIVE);
	if (SNDSTAT_PID(sndstat_dev) != 0) {
		lockmgr(&sndstat_lock, LK_RELEASE);
		return EBUSY;
	}
	if (td->td_proc == NULL) {
		SNDSTAT_PID_SET(sndstat_dev, -1);
	} else {
		SNDSTAT_PID_SET(sndstat_dev, td->td_proc->p_pid);
	}
	lockmgr(&sndstat_lock, LK_RELEASE);
	return 0;
}

int
sndstat_release(struct thread *td)
{
	if (sndstat_dev == NULL)
		return EBADF;

	lockmgr(&sndstat_lock, LK_EXCLUSIVE);
	if (td->td_proc == NULL) {
		if (SNDSTAT_PID(sndstat_dev) != -1) {
			lockmgr(&sndstat_lock, LK_RELEASE);
			return EBADF;
		}
	} else {
		if (SNDSTAT_PID(sndstat_dev) != td->td_proc->p_pid) {
			lockmgr(&sndstat_lock, LK_RELEASE);
			return EBADF;
		}
	}
	SNDSTAT_PID_SET(sndstat_dev, 0);
	lockmgr(&sndstat_lock, LK_RELEASE);
	return 0;
}

int
sndstat_register(device_t dev, char *str, sndstat_handler handler)
{
	struct sndstat_entry *ent;
	const char *devtype;
	int type, unit;

	if (dev) {
		unit = device_get_unit(dev);
		devtype = device_get_name(dev);
		if (!strcmp(devtype, "pcm"))
			type = SS_TYPE_PCM;
		else if (!strcmp(devtype, "midi"))
			type = SS_TYPE_MIDI;
		else if (!strcmp(devtype, "sequencer"))
			type = SS_TYPE_SEQUENCER;
		else
			return EINVAL;
	} else {
		type = SS_TYPE_MODULE;
		unit = -1;
	}

	ent = kmalloc(sizeof *ent, M_DEVBUF, M_WAITOK | M_ZERO);
	ent->dev = dev;
	ent->str = str;
	ent->type = type;
	ent->unit = unit;
	ent->handler = handler;

	lockmgr(&sndstat_lock, LK_EXCLUSIVE);
	SLIST_INSERT_HEAD(&sndstat_devlist, ent, link);
	if (type == SS_TYPE_MODULE)
		sndstat_files++;
	sndstat_maxunit = (unit > sndstat_maxunit)? unit : sndstat_maxunit;
	lockmgr(&sndstat_lock, LK_RELEASE);

	return 0;
}

int
sndstat_registerfile(char *str)
{
	return sndstat_register(NULL, str, NULL);
}

int
sndstat_unregister(device_t dev)
{
	struct sndstat_entry *ent;

	lockmgr(&sndstat_lock, LK_EXCLUSIVE);
	SLIST_FOREACH(ent, &sndstat_devlist, link) {
		if (ent->dev == dev) {
			SLIST_REMOVE(&sndstat_devlist, ent, sndstat_entry, link);
			lockmgr(&sndstat_lock, LK_RELEASE);
			kfree(ent, M_DEVBUF);

			return 0;
		}
	}
	lockmgr(&sndstat_lock, LK_RELEASE);

	return ENXIO;
}

int
sndstat_unregisterfile(char *str)
{
	struct sndstat_entry *ent;

	lockmgr(&sndstat_lock, LK_EXCLUSIVE);
	SLIST_FOREACH(ent, &sndstat_devlist, link) {
		if (ent->dev == NULL && ent->str == str) {
			SLIST_REMOVE(&sndstat_devlist, ent, sndstat_entry, link);
			sndstat_files--;
			lockmgr(&sndstat_lock, LK_RELEASE);
			kfree(ent, M_DEVBUF);

			return 0;
		}
	}
	lockmgr(&sndstat_lock, LK_RELEASE);

	return ENXIO;
}

/************************************************************************/

static int
sndstat_prepare(struct sbuf *s)
{
	struct sndstat_entry *ent;
	struct snddev_info *d;
    	int i, j;

	if (snd_verbose > 0) {
		sbuf_printf(s, "FreeBSD Audio Driver (%ubit %d/%s)\n",
		    (u_int)sizeof(intpcm32_t) << 3, SND_DRV_VERSION,
		    MACHINE_ARCH);
	}

	if (SLIST_EMPTY(&sndstat_devlist)) {
		sbuf_printf(s, "No devices installed.\n");
		sbuf_finish(s);
    		return sbuf_len(s);
	}

	sbuf_printf(s, "Installed devices:\n");

    	for (i = 0; i <= sndstat_maxunit; i++) {
		for (j = SS_TYPE_FIRST; j <= SS_TYPE_LAST; j++) {
			ent = sndstat_find(j, i);
			if (!ent)
				continue;
			d = device_get_softc(ent->dev);
			if (!PCM_REGISTERED(d))
				continue;
			/* XXX Need Giant magic entry ??? */
			PCM_ACQUIRE_QUICK(d);
			sbuf_printf(s, "%s:", device_get_nameunit(ent->dev));
			sbuf_printf(s, " <%s>", device_get_desc(ent->dev));
			if (snd_verbose > 0)
				sbuf_printf(s, " %s", ent->str);
			if (ent->handler)
				ent->handler(s, ent->dev, snd_verbose);
			sbuf_printf(s, "\n");
			PCM_RELEASE_QUICK(d);
		}
    	}

	if (snd_verbose >= 3 && sndstat_files > 0) {
		sbuf_printf(s, "\nFile Versions:\n");

		SLIST_FOREACH(ent, &sndstat_devlist, link) {
			if (ent->dev == NULL && ent->str != NULL)
				sbuf_printf(s, "%s\n", ent->str);
		}
	}

	sbuf_finish(s);
    	return sbuf_len(s);
}

static int
sndstat_init(void)
{
	if (sndstat_dev != NULL)
		return EINVAL;
	lockinit(&sndstat_lock, "sndstat lock", 0, LK_CANRECURSE);
	sndstat_dev = make_dev(&sndstat_cdevsw, SND_DEV_STATUS,
	    UID_ROOT, GID_WHEEL, 0444, "sndstat");
	return 0;
}

static int
sndstat_uninit(void)
{
	if (sndstat_dev == NULL)
		return EINVAL;

	lockmgr(&sndstat_lock, LK_EXCLUSIVE);
	if (SNDSTAT_PID(sndstat_dev) != curthread->td_proc->p_pid) {
		lockmgr(&sndstat_lock, LK_RELEASE);
		return EBUSY;
	}

	/* XXXPHO: use destroy_dev_sched() */
	destroy_dev(sndstat_dev);
	sndstat_dev = NULL;

	SNDSTAT_FLUSH();

	lockmgr(&sndstat_lock, LK_RELEASE);
	lockuninit(&sndstat_lock);
	return 0;
}

static void
sndstat_sysinit(void *p)
{
	sndstat_init();
}

static void
sndstat_sysuninit(void *p)
{
	int error;

	error = sndstat_uninit();
	KASSERT(error == 0, ("%s: error = %d", __func__, error));
}

SYSINIT(sndstat_sysinit, SI_SUB_DRIVERS, SI_ORDER_FIRST, sndstat_sysinit, NULL);
SYSUNINIT(sndstat_sysuninit, SI_SUB_DRIVERS, SI_ORDER_FIRST, sndstat_sysuninit, NULL);