Implement and use new mixer(3) library for FreeBSD.

Wiki article: https://wiki.freebsd.org/SummerOfCode2021Projects/SoundMixerImprovements
This project was part of Google Summer of Code 2021.

Submitted by:	christos@
Differential Revision:	https://reviews.freebsd.org/D31636
Sponsored by:	NVIDIA Networking

10 files changed, 1787 insertions, 544 deletions

diff --git a/lib/Makefile b/lib/Makefile
index 1e375bb456e6..038763bfcba8 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -69,6 +69,7 @@ SUBDIR=	${SUBDIR_BOOTSTRAP} \
 	liblzma \
 	libmemstat \
 	libmd \
+	libmixer \
 	libmt \
 	lib80211 \
 	libnetbsd \
diff --git a/lib/libmixer/Makefile b/lib/libmixer/Makefile
new file mode 100644
index 000000000000..12081ee3835b
--- /dev/null
+++ b/lib/libmixer/Makefile
@@ -0,0 +1,8 @@
+# $FreeBSD$
+
+LIB=		mixer
+SRCS=		${LIB}.c
+INCS=		${LIB}.h
+MAN=		${LIB}.3
+
+.include <bsd.lib.mk>
diff --git a/lib/libmixer/mixer.3 b/lib/libmixer/mixer.3
new file mode 100644
index 000000000000..f97a88bb79a0
--- /dev/null
+++ b/lib/libmixer/mixer.3
@@ -0,0 +1,540 @@
+.\"-
+.\" Copyright (c) 2021 Christos Margiolis <christos@FreeBSD.org>
+.\"
+.\" Permission is hereby granted, free of charge, to any person obtaining a copy
+.\" of this software and associated documentation files (the "Software"), to deal
+.\" in the Software without restriction, including without limitation the rights
+.\" to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+.\" copies of the Software, and to permit persons to whom the Software is
+.\" furnished to do so, subject to the following conditions:
+.\"
+.\" The above copyright notice and this permission notice shall be included in
+.\" all copies or substantial portions of the Software.
+.\"
+.\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+.\" IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+.\" FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+.\" AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+.\" LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+.\" OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+.\" THE SOFTWARE.
+.\"
+.\" $FreeBSD$
+.\"
+
+.Dd June 30, 2021
+.Dt mixer 3
+.Os
+.Sh NAME
+.Nm mixer_open ,
+.Nm mixer_close ,
+.Nm mixer_get_dev ,
+.Nm mixer_get_dev_byname ,
+.Nm mixer_add_ctl ,
+.Nm mixer_add_ctl_s ,
+.Nm mixer_remove_ctl ,
+.Nm mixer_get_ctl ,
+.Nm mixer_get_ctl_byname ,
+.Nm mixer_set_vol ,
+.Nm mixer_set_mute ,
+.Nm mixer_mod_recsrc ,
+.Nm mixer_get_dunit ,
+.Nm mixer_set_dunit ,
+.Nm mixer_get_mode,
+.Nm mixer_get_nmixers ,
+.Nm MIX_ISDEV ,
+.Nm MIX_ISMUTE ,
+.Nm MIX_ISREC ,
+.Nm MIX_ISRECSRC ,
+.Nm MIX_VOLNORM ,
+.Nm MIX_VOLDENORM
+.Nd interface to OSS mixers
+.Sh LIBRARY
+Mixer library (libmixer, -lmixer)
+.Sh SYNOPSIS
+.In mixer.h
+.Ft struct mixer *
+.Fn mixer_open "const char *name"
+.Ft int
+.Fn mixer_close "struct mixer *m"
+.Ft struct mix_dev *
+.Fn mixer_get_dev "struct mixer *m" "int devno"
+.Ft struct mix_dev *
+.Fn mixer_get_dev_byname "struct mixer *m" "name"
+.Ft int
+.Fn mixer_add_ctl "struct mix_dev *parent" "int id" "const char *name" \
+    "int (*mod)(struct mix_dev *d, void *p)" \
+    "int (*print)(struct mix_dev *d, void *p)
+.Ft int
+.Fn mixer_add_ctl_s "mix_ctl_t *ctl"
+.Ft int
+.Fn mixer_remove_ctl "mix_ctl_t *ctl"
+.Ft mix_ctl_t *
+.Fn mixer_get_ctl "struct mix_dev *d" "int id"
+.Ft mix_ctl_t *
+.Fn mixer_get_ctl_byname "struct mix_dev *d" "const char *name"
+.Ft int
+.Fn mixer_set_vol "struct mixer *m" "mix_volume_t vol"
+.Ft int
+.Fn mixer_set_mute "struct mixer *m" "int opt"
+.Ft int
+.Fn mixer_mod_recsrc "struct mixer *m" "int opt"
+.Ft int
+.Fn mixer_get_dunit "void"
+.Ft int
+.Fn mixer_set_dunit "struct mixer *m" "int unit"
+.Ft int
+.Fn mixer_get_mode "int unit"
+.Ft int
+.Fn mixer_get_nmixers "void"
+.Ft int
+.Fn MIX_ISDEV "struct mixer *m" "int devno"
+.Ft int
+.Fn MIX_ISMUTE "struct mixer *m" "int devno"
+.Ft int
+.Fn MIX_ISREC "struct mixer *m" "int devno"
+.Ft int
+.Fn MIX_ISRECSRC "struct mixer *m" "int devno"
+.Ft float
+.Fn MIX_VOLNORM "int v"
+.Ft int
+.Fn MIX_VOLDENORM "float v"
+.Sh DESCRIPTION
+The
+.Nm mixer
+library allows userspace programs to access and manipulate OSS sound mixers in
+a simple way.
+.Ss Mixer
+.Pp
+A mixer is described by the following structure:
+.Bd -literal
+struct mixer {
+	TAILQ_HEAD(, mix_dev) devs;		/* device list */
+	struct mix_dev *dev;			/* selected device */
+	oss_mixerinfo mi;			/* mixer info */
+	oss_card_info ci;			/* audio card info */
+	char name[NAME_MAX];			/* mixer name (e.g /dev/mixer0) */
+	int fd;					/* file descriptor */
+	int unit;				/* audio card unit */
+	int ndev;				/* number of devices */
+	int devmask;				/* supported devices */
+#define MIX_MUTE		0x01
+#define MIX_UNMUTE		0x02
+#define MIX_TOGGLEMUTE		0x04
+	int mutemask;				/* muted devices */
+	int recmask;				/* recording devices */
+#define MIX_ADDRECSRC		0x01
+#define MIX_REMOVERECSRC	0x02
+#define MIX_SETRECSRC		0x04
+#define MIX_TOGGLERECSRC	0x08
+	int recsrc;				/* recording sources */
+#define MIX_MODE_MIXER		0x01
+#define MIX_MODE_PLAY		0x02
+#define MIX_MODE_REC		0x04
+	int mode;				/* dev.pcm.X.mode sysctl */
+	int f_default;				/* default mixer flag */
+};
+.Ed
+.Pp
+The fields are follows:
+.Bl -tag -width "f_default"
+.It Fa devs
+A tail queue structure containing all supported mixer devices.
+.It Fa dev
+A pointer to the currently selected device. The device is one of the elements in
+.Ar devs .
+.It Fa mi
+OSS information about the mixer. Look at the definition of the
+.Ft oss_mixerinfo
+structure in
+.In sys/soundcard.h
+to see its fields.
+.It Fa ci
+OSS audio card information. This structure is also defined in
+.In sys/soundcard.h .
+.It Fa name
+Path to the mixer (e.g /dev/mixer0).
+.It Fa fd
+File descriptor returned when the mixer is opened in
+.Fn mixer_open .
+.It Fa unit
+Audio card unit. Since each mixer device maps to a pcmX device,
+.Ar unit
+is always equal to the number of that pcmX device. For example, if the audio
+device's number is 0 (i.e pcm0), then
+.Ar unit
+is 0 as well. This number is useful when checking if the mixer's audio
+card is the default one.
+.It Fa ndev
+Number of devices in
+.Ar devs .
+.It Fa devmask
+Bit mask containing all supported devices for the mixer. For example
+if device 10 is supported, then the 10th bit in the mask will be set. By default,
+.Fn mixer_open
+stores only the supported devices in devs, so it's very unlikely this mask will
+be needed.
+.It Fa mutemask
+Bit mask containing all muted devices. The logic is the same as with
+.Ar devmask .
+.It Fa recmask
+Bit mask containing all recording devices. Again, same logic as with the
+other masks.
+.It Fa recsrc
+Bit mask containing all recording sources. Yes, same logic again.
+.It Fa mode
+Bit mask containing the supported modes for this audio device. It holds the value
+of the
+.Ar dev.pcm.X.mode
+sysctl.
+.It Fa f_default
+Flag which tells whether the mixer's audio card is the default one.
+.El
+.Ss Mixer device
+.Pp
+Each mixer device stored in a mixer is described as follows:
+.Bd -literal
+struct mix_dev {
+	struct mixer *parent_mixer;		/* parent mixer */
+	char name[NAME_MAX];			/* device name (e.g "vol") */
+	int devno;				/* device number */
+	struct mix_volume {
+#define MIX_VOLMIN		0.0f
+#define MIX_VOLMAX		1.0f
+#define MIX_VOLNORM(v)		((v) / 100.0f)
+#define MIX_VOLDENORM(v)	((int)((v) * 100.0f + 0.5f))
+		float left;			/* left volume */
+		float right;			/* right volume */
+	} vol;
+	int nctl;				/* number of controls */
+	TAILQ_HEAD(, mix_ctl) ctls;		/* control list */
+	TAILQ_ENTRY(mix_dev) devs;
+};
+.Ed
+.Pp
+The fields are follows:
+.Bl -tag -width "parent_mixer"
+.It Fa parent_mixer
+Pointer to the mixer the device is attached to.
+.It Fa name
+Device name given by the OSS API. Devices can have one of the following names:
+.Bd -ragged
+vol, bass, treble, synth, pcm, speaker, line, mic, cd, mix,
+pcm2, rec, igain, ogain, line1, line2, line3, dig1, dig2, dig3,
+phin, phout, video, radio, and monitor.
+.Ed
+.It Fa devno
+Device's index in the SOUND_MIXER_NRDEVICES macro defined in
+.In sys/soundcard.h .
+This number is used to check against the masks defined in the
+.Ar mixer
+structure.
+.It Fa left, right
+Left and right-ear volumes. Although the OSS API stores volumes in integers from
+0-100, we normalize them to 32-bit floating point numbers. However, the volumes
+can be denormalized using the
+.Ar MIX_VOLDENORM
+macro if needed.
+.It Fa nctl
+Number of user-defined mixer controls associated with the device.
+.It Fa ctls
+A tail queue containing user-defined mixer controls.
+.El
+.Ss User-defined mixer controls
+.Pp
+Each mixer device can have user-defined controls. The control structure
+is defined as follows:
+.Bd -literal
+struct mix_ctl {
+	struct mix_dev *parent_dev;		/* parent device */
+	int id;					/* control id */
+	char name[NAME_MAX];			/* control name */
+	int (*mod)(struct mix_dev *, void *);	/* modify control values */
+	int (*print)(struct mix_dev *, void *);	/* print control */
+	TAILQ_ENTRY(mix_ctl) ctls;
+};
+.Ed
+.Pp
+The fields are follows:
+.Bl -tag -width "parent_dev"
+.It Fa parent_dev
+Pointer to the device the control is attached to.
+.It Fa id
+Control ID assigned by the caller. Even though the library will
+report it, care has to be taken to not give a control the same ID in case
+the caller has to choose controls using their ID.
+.It Fa name
+Control name. As with
+.Ar id ,
+the caller has to make sure the same name is not used more than once.
+.It Fa mod
+Function pointer to a control modification function. As in
+.Xr mixer 8 ,
+each mixer control's values can be modified. For example, if we have a
+volume control, the
+.Ar mod
+function will be responsible for handling volume changes.
+.It Fa print
+Function pointer to a control print function.
+.El
+.Ss Opening and closing the mixer
+.Pp
+The application must first call the
+.Fn mixer_open
+function to obtain a handle to the device, which is used as an argument
+in most other functions and macros. The parameter
+.Ar name
+specifies the path to the mixer. OSS mixers are stored under
+.Ar /dev/mixerN
+where
+.Ar N
+is the number of the mixer device. Each device maps to an actual
+.Ar pcm
+audio card, so
+.Ar /dev/mixer0
+is the mixer for
+.Ar pcm0 ,
+and so on. If
+.Ar name
+is
+.Ar NULL
+or
+.Ar /dev/mixer ,
+.Fn mixer_open
+opens the default mixer (hw.snd.defaul_unit).
+.Pp
+The
+.Fn mixer_close
+function frees resources and closes the mixer device. It's a good practice to
+always call it when the application is done using the mixer.
+.Ss Manipulating the mixer
+.Pp
+The
+.Fn mixer_get_dev
+and
+.Fn mixer_get_dev_byname
+functions select a mixer device, either by its number or by its name
+respectively. The mixer structure keeps a list of all the devices, but only
+one can be manipulated at a time. Each time a new device is to be manipulated,
+one of the two functions has to be called.
+.Pp
+The
+.Fn mixer_set_vol
+function changes the volume of the selected mixer device. The
+.Ar vol
+parameter is a structure that stores the left and right volumes of a given
+device. The allowed volume values are between MIX_VOLMIN (0.0) and
+MIX_VOLMAX (1.0).
+.Pp
+The
+.Fn mixer_set_mute
+function modifies the mute of a selected device. The
+.Ar opt
+parameter has to be one of the following options:
+.Bl -tag -width MIX_TOGGLEMUTE -offset indent
+.It Dv MIX_MUTE
+Mute the device.
+.It Dv MIX_UNMUTE
+Unmute the device.
+.It Dv MIX_TOGGLEMUTE
+Toggle the device's mute (e.g mute if unmuted and unmute if muted).
+.El
+.Pp
+The
+.Fn mixer_mod_recsrc
+function modifies a recording device. The selected device has to be
+a recording device, otherwise the function will fail. The
+.Ar opt
+parameter has to be one of the following options:
+.Bl -tag -width MIX_REMOVERECSRC -offset indent
+.It Dv MIX_ADDRECSRC
+Add device to the recording sources.
+.It Dv MIX_REMOVERECSRC
+Remove device from the recording sources.
+.It Dv MIX_SETRECSRC
+Set device as the only recording source.
+.It Dv MIX_TOGGLERECSRC
+Toggle device from the recording sources.
+.El
+.Pp
+The
+.Fn mixer_get_dunit
+and
+.Fn mixer_set_dunit
+functions get and set the default audio card in the system. Although this is
+not really a mixer feature, it's useful to have instead of having to use
+the
+.Xr sysctl 3
+controls.
+.Pp
+The
+.Fn mixer_get_mode
+function returns the playback/recording mode of the audio device the mixer
+belongs to. The available values are the following:
+.Bl -tag -width "MIX_STATUS_PLAY | MIX_STATUS_REC" -offset indent
+.It Dv MIX_STATUS_NONE
+Neither playback nor recording.
+.It Dv MIX_STATUS_PLAY
+Playback.
+.It Dv MIX_STATUS_REC
+Recording.
+.It Dv MIX_STATUS_PLAY | MIX_STATUS_REC
+Playback and recording.
+.El
+.Pp
+The
+.Fn mixer_get_nmixers
+function returns the total number of mixer devices in the system.
+.Pp
+The
+.Fn MIX_ISDEV
+macro checks if a device is actually a valid device for a given mixer. It's very
+unlikely that this macro will ever be needed since the library stores only
+valid devices by default.
+.Pp
+The
+.Fn MIX_ISMUTE
+macro checks if a device is muted.
+.Pp
+The
+.Fn MIX_ISREC
+macro checks if a device is a recording device.
+.Pp
+The
+.Fn MIX_ISRECSRC
+macro checks if a device is a recording source.
+.Pp
+The
+.Fn MIX_VOLNORM
+macro normalizes a value to 32-bit floating point number. It's used
+to normalize the volumes read from the OSS API.
+.Pp
+The
+.Fn MIX_VOLDENORM
+macro denormalizes the left and right volumes stores in the
+.Ft mix_dev
+structure.
+.Ss Defining and using mixer controls
+.Pp
+The
+.Fn mix_add_ctl
+function creates a control and attaches it to the device specified in the
+.Ar parent
+argument.
+.Pp
+The
+.Fn mix_add_ctl_s
+function does the same thing as with
+.Fn mix_add_ctl
+but the caller passes a
+.Ft mix_ctl_t *
+structure instead of each field as a seperate argument.
+.Pp
+The
+.Fn mixer_remove_ctl
+functions removes a control from the device its attached to.
+.Pp
+The
+.Fn mixer_get_ctl
+function searches for a control in the device specified in the
+.Ar d
+argument and returns a pointer to it. The search is done using the control's ID.
+.Pp
+The
+.Fn mixer_get_ctl_byname
+function is the same as with
+.Fn mixer_get_ctl
+but the search is done using the control's name.
+.Sh RETURN VALUES
+.Pp
+The
+.Fn mixer_open
+function returns the newly created handle on success and NULL on failure.
+.Pp
+The
+.Fn mixer_close ,
+.Fn mixer_set_vol ,
+.Fn mixer_set_mute ,
+.Fn mixer_mod_recsrc ,
+.Fn mixer_get_dunut ,
+.Fn mixer_set_dunit
+and
+.Fn mixer_get_nmixers
+functions return 0 or positive values on success and -1 on failure.
+.Pp
+The
+.Fn mixer_get_dev
+and
+.Fn mixer_get_dev_byname
+functions return the selected device on success and NULL on failure.
+.Pp
+All functions set the value of
+.Ar errno
+on failure.
+.Sh EXAMPLES
+.Ss Change the volume of a device
+.Bd -literal
+struct mixer *m;
+mix_volume_t vol;
+char *mix_name, *dev_name;
+
+mix_name = ...;
+if ((m = mixer_open(mix_name)) == NULL)
+	err(1, "mixer_open: %s", mix_name);
+
+dev_name = ...;
+if ((m->dev = mixer_get_dev_byname(m, dev_name)) < 0)
+	err(1, "unknown device: %s", dev_name);
+
+vol.left = ...;
+vol.right = ....;
+if (mixer_set_vol(m, vol) < 0)
+	warn("cannot change volume");
+
+(void)mixer_close(m);
+.Ed
+.Ss Mute all unmuted devices
+.Bd -literal
+struct mixer *m;
+struct mix_dev *dp;
+
+if ((m = mixer_open(NULL)) == NULL)	/* Open the default mixer. */
+	err(1, "mixer_open");
+TAILQ_FOREACH(dp, &m->devs, devs) {
+	m->dev = dp;			/* Select device. */
+	if (M_ISMUTE(m, dp->devno))
+		continue;
+	if (mixer_set_mute(m, MIX_MUTE) < 0)
+		warn("cannot mute device: %s", dp->name);
+}
+
+(void)mixer_close(m);
+.Ed
+.Ss Print all recording sources' names and volumes
+.Bd -literal
+struct mixer *m;
+struct mix_dev *dp;
+
+char *mix_name, *dev_name;
+
+mix_name = ...;
+if ((m = mixer_open(mix_name)) == NULL)
+	err(1, "mixer_open: %s", mix_name);
+
+TAILQ_FOREACH(dp, &m->devs, devs) {
+	if (M_ISRECSRC(m, dp->devno))
+		printf("%s\\t%.2f:%.2f\\n",
+		    dp->name, dp->vol.left, dp->vol.right);
+}
+
+(void)mixer_close(m);
+.Ed
+.Sh SEE ALSO
+.Xr mixer 8 ,
+.Xr sound 4 ,
+.Xr sysctl 3 ,
+.Xr queue 3
+and
+.Xr errno 2
+.Sh AUTHORS
+.An Christos Margiolis Aq Mt christos@margiolis.net
diff --git a/lib/libmixer/mixer.c b/lib/libmixer/mixer.c
new file mode 100644
index 000000000000..b10d5c6607cf
--- /dev/null
+++ b/lib/libmixer/mixer.c
@@ -0,0 +1,493 @@
+/*-
+ * Copyright (c) 2021 Christos Margiolis <christos@FreeBSD.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/sysctl.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "mixer.h"
+
+#define	BASEPATH "/dev/mixer"
+
+static int _mixer_readvol(struct mixer *, struct mix_dev *);
+
+/*
+ * Fetch volume from the device.
+ */
+static int
+_mixer_readvol(struct mixer *m, struct mix_dev *dev)
+{
+	int v;
+
+	if (ioctl(m->fd, MIXER_READ(dev->devno), &v) < 0)
+		return (-1);
+	dev->vol.left = MIX_VOLNORM(v & 0x00ff);
+	dev->vol.right = MIX_VOLNORM((v >> 8) & 0x00ff);
+
+	return (0);
+}
+
+/*
+ * Open a mixer device in `/dev/mixerN`, where N is the number of the mixer.
+ * Each device maps to an actual pcm audio card, so `/dev/mixer0` is the
+ * mixer for pcm0, and so on.
+ *
+ * @param name		path to mixer device. NULL or "/dev/mixer" for the
+ *			the default mixer (i.e `hw.snd.default_unit`).
+ */
+struct mixer *
+mixer_open(const char *name)
+{
+	struct mixer *m = NULL;
+	struct mix_dev *dp;
+	const char *names[SOUND_MIXER_NRDEVICES] = SOUND_DEVICE_NAMES;
+	int i;
+
+	if ((m = calloc(1, sizeof(struct mixer))) == NULL)
+		goto fail;
+
+	if (name != NULL) {
+		/* `name` does not start with "/dev/mixer". */
+		if (strncmp(name, BASEPATH, strlen(BASEPATH)) != 0) {
+			errno = EINVAL;
+			goto fail;
+		}
+		/* `name` is "/dev/mixer" so, we'll use the default unit. */
+		if (strncmp(name, BASEPATH, strlen(name)) == 0)
+			goto dunit;
+		m->unit = strtol(name + strlen(BASEPATH), NULL, 10);
+		(void)strlcpy(m->name, name, sizeof(m->name));
+	} else {
+dunit:
+		if ((m->unit = mixer_get_dunit()) < 0)
+			goto fail;
+		(void)snprintf(m->name, sizeof(m->name), "/dev/mixer%d", m->unit);
+	}
+
+	if ((m->fd = open(m->name, O_RDWR)) < 0)
+		goto fail;
+
+	m->devmask = m->recmask = m->recsrc = 0;
+	m->f_default = m->unit == mixer_get_dunit();
+	m->mode = mixer_get_mode(m->unit);
+	/* The unit number _must_ be set before the ioctl. */
+	m->mi.dev = m->unit;
+	m->ci.card = m->unit;
+	if (ioctl(m->fd, SNDCTL_MIXERINFO, &m->mi) < 0 ||
+	    ioctl(m->fd, SNDCTL_CARDINFO, &m->ci) < 0 ||
+	    ioctl(m->fd, SOUND_MIXER_READ_DEVMASK, &m->devmask) < 0 ||
+	    ioctl(m->fd, SOUND_MIXER_READ_MUTE, &m->mutemask) < 0 ||
+	    ioctl(m->fd, SOUND_MIXER_READ_RECMASK, &m->recmask) < 0 ||
+	    ioctl(m->fd, SOUND_MIXER_READ_RECSRC, &m->recsrc) < 0)
+		goto fail;
+
+	TAILQ_INIT(&m->devs);
+	for (i = 0; i < SOUND_MIXER_NRDEVICES; i++) {
+		if (!MIX_ISDEV(m, i))
+			continue;
+		if ((dp = calloc(1, sizeof(struct mix_dev))) == NULL)
+			goto fail;
+		dp->parent_mixer = m;
+		dp->devno = i;
+		dp->nctl = 0;
+		if (_mixer_readvol(m, dp) < 0)
+			goto fail;
+		(void)strlcpy(dp->name, names[i], sizeof(dp->name));
+		TAILQ_INIT(&dp->ctls);
+		TAILQ_INSERT_TAIL(&m->devs, dp, devs);
+		m->ndev++;
+	}
+
+	/* The default device is always "vol". */
+	m->dev = TAILQ_FIRST(&m->devs);
+
+	return (m);
+fail:
+	if (m != NULL)
+		(void)mixer_close(m);
+
+	return (NULL);
+}
+
+/*
+ * Free resources and close the mixer.
+ */
+int
+mixer_close(struct mixer *m)
+{
+	struct mix_dev *dp;
+	int r;
+
+	r = close(m->fd);
+	while (!TAILQ_EMPTY(&m->devs)) {
+		dp = TAILQ_FIRST(&m->devs);
+		TAILQ_REMOVE(&m->devs, dp, devs);
+		while (!TAILQ_EMPTY(&dp->ctls))
+			(void)mixer_remove_ctl(TAILQ_FIRST(&dp->ctls));
+		free(dp);
+	}
+	free(m);
+
+	return (r);
+}
+
+/*
+ * Select a mixer device. The mixer structure keeps a list of all the devices
+ * the mixer has, but only one can be manipulated at a time -- this is what
+ * the `dev` in the mixer structure field is for. Each time a device is to be
+ * manipulated, `dev` has to point to it first.
+ *
+ * The caller must manually assign the return value to `m->dev`.
+ */
+struct mix_dev *
+mixer_get_dev(struct mixer *m, int dev)
+{
+	struct mix_dev *dp;
+
+	if (dev < 0 || dev >= m->ndev) {
+		errno = ERANGE;
+		return (NULL);
+	}
+	TAILQ_FOREACH(dp, &m->devs, devs) {
+		if (dp->devno == dev)
+			return (dp);
+	}
+	errno = EINVAL;
+
+	return (NULL);
+}
+
+/*
+ * Select a device by name.
+ *
+ * @param name		device name (e.g vol, pcm, ...)
+ */
+struct mix_dev *
+mixer_get_dev_byname(struct mixer *m, const char *name)
+{
+	struct mix_dev *dp;
+
+	TAILQ_FOREACH(dp, &m->devs, devs) {
+		if (!strncmp(dp->name, name, sizeof(dp->name)))
+			return (dp);
+	}
+	errno = EINVAL;
+
+	return (NULL);
+}
+
+/*
+ * Add a mixer control to a device.
+ */
+int
+mixer_add_ctl(struct mix_dev *parent_dev, int id, const char *name,
+    int (*mod)(struct mix_dev *, void *),
+    int (*print)(struct mix_dev *, void *))
+{
+	struct mix_dev *dp;
+	mix_ctl_t *ctl, *cp;
+
+	/* XXX: should we accept NULL name? */
+	if (parent_dev == NULL) {
+		errno = EINVAL;
+		return (-1);
+	}
+	if ((ctl = calloc(1, sizeof(mix_ctl_t))) == NULL)
+		return (-1);
+	ctl->parent_dev = parent_dev;
+	ctl->id = id;
+	if (name != NULL)
+		(void)strlcpy(ctl->name, name, sizeof(ctl->name));
+	ctl->mod = mod;
+	ctl->print = print;
+	dp = ctl->parent_dev;
+	/* Make sure the same ID or name doesn't exist already. */
+	TAILQ_FOREACH(cp, &dp->ctls, ctls) {
+		if (!strncmp(cp->name, name, sizeof(cp->name)) || cp->id == id) {
+			errno = EINVAL;
+			return (-1);
+		}
+	}
+	TAILQ_INSERT_TAIL(&dp->ctls, ctl, ctls);
+	dp->nctl++;
+
+	return (0);
+}
+
+/*
+ * Same as `mixer_add_ctl`.
+ */
+int
+mixer_add_ctl_s(mix_ctl_t *ctl)
+{
+	if (ctl == NULL)
+		return (-1);
+
+	return (mixer_add_ctl(ctl->parent_dev, ctl->id, ctl->name,
+	    ctl->mod, ctl->print));
+}
+
+/*
+ * Remove a mixer control from a device.
+ */
+int
+mixer_remove_ctl(mix_ctl_t *ctl)
+{
+	struct mix_dev *p;
+
+	if (ctl == NULL) {
+		errno = EINVAL;
+		return (-1);
+	}
+	p = ctl->parent_dev;
+	if (!TAILQ_EMPTY(&p->ctls)) {
+		TAILQ_REMOVE(&p->ctls, ctl, ctls);
+		free(ctl);
+	}
+
+	return (0);
+}
+
+/*
+ * Get a mixer control by id.
+ */
+mix_ctl_t *
+mixer_get_ctl(struct mix_dev *d, int id)
+{
+	mix_ctl_t *cp;
+
+	TAILQ_FOREACH(cp, &d->ctls, ctls) {
+		if (cp->id == id)
+			return (cp);
+	}
+	errno = EINVAL;
+
+	return (NULL);
+}
+
+/*
+ * Get a mixer control by name.
+ */
+mix_ctl_t *
+mixer_get_ctl_byname(struct mix_dev *d, const char *name)
+{
+	mix_ctl_t *cp;
+
+	TAILQ_FOREACH(cp, &d->ctls, ctls) {
+		if (!strncmp(cp->name, name, sizeof(cp->name)))
+			return (cp);
+	}
+	errno = EINVAL;
+
+	return (NULL);
+}
+
+/*
+ * Change the mixer's left and right volume. The allowed volume values are
+ * between MIX_VOLMIN and MIX_VOLMAX. The `ioctl` for volume change requires
+ * an integer value between 0 and 100 stored as `lvol | rvol << 8` --  for
+ * that reason, we de-normalize the 32-bit float volume value, before
+ * we pass it to the `ioctl`.
+ *
+ * Volume clumping should be done by the caller.
+ */
+int
+mixer_set_vol(struct mixer *m, mix_volume_t vol)
+{
+	int v;
+
+	if (vol.left < MIX_VOLMIN || vol.left > MIX_VOLMAX ||
+	    vol.right < MIX_VOLMIN || vol.right > MIX_VOLMAX) {
+		errno = ERANGE;
+		return (-1);
+	}
+	v = MIX_VOLDENORM(vol.left) | MIX_VOLDENORM(vol.right) << 8;
+	if (ioctl(m->fd, MIXER_WRITE(m->dev->devno), &v) < 0)
+		return (-1);
+	if (_mixer_readvol(m, m->dev) < 0)
+		return (-1);
+
+	return (0);
+}
+
+/*
+ * Manipulate a device's mute.
+ *
+ * @param opt		MIX_MUTE mute device
+ *			MIX_UNMUTE unmute device
+ *			MIX_TOGGLEMUTE toggle device's mute
+ */
+int
+mixer_set_mute(struct mixer *m, int opt)
+{
+	switch (opt) {
+	case MIX_MUTE:
+		m->mutemask |= (1 << m->dev->devno);
+		break;
+	case MIX_UNMUTE:
+		m->mutemask &= ~(1 << m->dev->devno);
+		break;
+	case MIX_TOGGLEMUTE:
+		m->mutemask ^= (1 << m->dev->devno);
+		break;
+	default:
+		errno = EINVAL;
+		return (-1);
+	}
+	if (ioctl(m->fd, SOUND_MIXER_WRITE_MUTE, &m->mutemask) < 0)
+		return (-1);
+	if (ioctl(m->fd, SOUND_MIXER_READ_MUTE, &m->mutemask) < 0)
+		return (-1);
+
+	return 0;
+}
+
+/*
+ * Modify a recording device. The selected device has to be a recording device,
+ * otherwise the function will fail.
+ *
+ * @param opt		MIX_ADDRECSRC add device to recording sources
+ *			MIX_REMOVERECSRC remove device from recording sources
+ *			MIX_SETRECSRC set device as the only recording source
+ *			MIX_TOGGLERECSRC toggle device from recording sources
+ */
+int
+mixer_mod_recsrc(struct mixer *m, int opt)
+{
+	if (!m->recmask || !MIX_ISREC(m, m->dev->devno)) {
+		errno = ENODEV;
+		return (-1);
+	}
+	switch (opt) {
+	case MIX_ADDRECSRC:
+		m->recsrc |= (1 << m->dev->devno);
+		break;
+	case MIX_REMOVERECSRC:
+		m->recsrc &= ~(1 << m->dev->devno);
+		break;
+	case MIX_SETRECSRC:
+		m->recsrc = (1 << m->dev->devno);
+		break;
+	case MIX_TOGGLERECSRC:
+		m->recsrc ^= (1 << m->dev->devno);
+		break;
+	default:
+		errno = EINVAL;
+		return (-1);
+	}
+	if (ioctl(m->fd, SOUND_MIXER_WRITE_RECSRC, &m->recsrc) < 0)
+		return (-1);
+	if (ioctl(m->fd, SOUND_MIXER_READ_RECSRC, &m->recsrc) < 0)
+		return (-1);
+
+	return (0);
+}
+
+/*
+ * Get default audio card's number. This is used to open the default mixer
+ * and set the mixer structure's `f_default` flag.
+ */
+int
+mixer_get_dunit(void)
+{
+	size_t size;
+	int unit;
+
+	size = sizeof(int);
+	if (sysctlbyname("hw.snd.default_unit", &unit, &size, NULL, 0) < 0)
+		return (-1);
+
+	return (unit);
+}
+
+/*
+ * Change the default audio card. This is normally _not_ a mixer feature, but
+ * it's useful to have, so the caller can avoid having to manually use
+ * the sysctl API.
+ *
+ * @param unit		the audio card number (e.g pcm0, pcm1, ...).
+ */
+int
+mixer_set_dunit(struct mixer *m, int unit)
+{
+	size_t size;
+
+	size = sizeof(int);
+	if (sysctlbyname("hw.snd.default_unit", NULL, 0, &unit, size) < 0)
+		return (-1);
+	/* XXX: how will other mixers get updated? */
+	m->f_default = m->unit == unit;
+
+	return (0);
+}
+
+/*
+ * Get sound device mode (none, play, rec, play+rec). Userland programs can
+ * use the MIX_STATUS_* flags to determine the mode of the device.
+ */
+int
+mixer_get_mode(int unit)
+{
+	char buf[64];
+	size_t size;
+	unsigned int mode;
+
+	(void)snprintf(buf, sizeof(buf), "dev.pcm.%d.mode", unit);
+	size = sizeof(unsigned int);
+	if (sysctlbyname(buf, &mode, &size, NULL, 0) < 0)
+		return (-1);
+
+	return (mode);
+}
+
+/*
+ * Get the total number of mixers in the system.
+ */
+int
+mixer_get_nmixers(void)
+{
+	struct mixer *m;
+	oss_sysinfo si;
+
+	/*
+	 * Open a dummy mixer because we need the `fd` field for the
+	 * `ioctl` to work.
+	 */
+	if ((m = mixer_open(NULL)) == NULL)
+		return (-1);
+	if (ioctl(m->fd, OSS_SYSINFO, &si) < 0) {
+		(void)mixer_close(m);
+		return (-1);
+	}
+	(void)mixer_close(m);
+
+	return (si.nummixers);
+}
diff --git a/lib/libmixer/mixer.h b/lib/libmixer/mixer.h
new file mode 100644
index 000000000000..6e77fdec421f
--- /dev/null
+++ b/lib/libmixer/mixer.h
@@ -0,0 +1,123 @@
+/*-
+ * Copyright (c) 2021 Christos Margiolis <christos@FreeBSD.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _MIXER_H_
+#define _MIXER_H_
+
+#include <sys/cdefs.h>
+#include <sys/queue.h>
+#include <sys/soundcard.h>
+
+#include <limits.h>
+
+#define MIX_ISSET(n,f)		(((1U << (n)) & (f)) ? 1 : 0)
+#define MIX_ISDEV(m,n)		MIX_ISSET(n, (m)->devmask)
+#define MIX_ISMUTE(m,n)		MIX_ISSET(n, (m)->mutemask)
+#define MIX_ISREC(m,n)		MIX_ISSET(n, (m)->recmask)
+#define MIX_ISRECSRC(m,n)	MIX_ISSET(n, (m)->recsrc)
+
+/* Forward declarations */
+struct mixer;
+struct mix_dev;
+
+typedef struct mix_ctl mix_ctl_t;
+typedef struct mix_volume mix_volume_t;
+
+/* User-defined controls */
+struct mix_ctl {
+	struct mix_dev *parent_dev;		/* parent device */
+	int id;					/* control id */
+	char name[NAME_MAX];			/* control name */
+	int (*mod)(struct mix_dev *, void *);	/* modify control values */
+	int (*print)(struct mix_dev *, void *);	/* print control */
+	TAILQ_ENTRY(mix_ctl) ctls;
+};
+
+struct mix_dev {
+	struct mixer *parent_mixer;		/* parent mixer */
+	char name[NAME_MAX];			/* device name (e.g "vol") */
+	int devno;				/* device number */
+	struct mix_volume {
+#define MIX_VOLMIN		0.0f
+#define MIX_VOLMAX		1.0f
+#define MIX_VOLNORM(v)		((v) / 100.0f)
+#define MIX_VOLDENORM(v)	((int)((v) * 100.0f + 0.5f))
+		float left;			/* left volume */
+		float right;			/* right volume */
+	} vol;
+	int nctl;				/* number of controls */
+	TAILQ_HEAD(, mix_ctl) ctls;		/* control list */
+	TAILQ_ENTRY(mix_dev) devs;
+};
+
+struct mixer {
+	TAILQ_HEAD(, mix_dev) devs;		/* device list */
+	struct mix_dev *dev;			/* selected device */
+	oss_mixerinfo mi;			/* mixer info */
+	oss_card_info ci;			/* audio card info */
+	char name[NAME_MAX];			/* mixer name (e.g /dev/mixer0) */
+	int fd;					/* file descriptor */
+	int unit;				/* audio card unit */
+	int ndev;				/* number of devices */
+	int devmask;				/* supported devices */
+#define MIX_MUTE		0x01
+#define MIX_UNMUTE		0x02
+#define MIX_TOGGLEMUTE		0x04
+	int mutemask;				/* muted devices */
+	int recmask;				/* recording devices */
+#define MIX_ADDRECSRC		0x01
+#define MIX_REMOVERECSRC	0x02
+#define MIX_SETRECSRC		0x04
+#define MIX_TOGGLERECSRC	0x08
+	int recsrc;				/* recording sources */
+#define MIX_MODE_MIXER		0x01
+#define MIX_MODE_PLAY		0x02
+#define MIX_MODE_REC		0x04
+	int mode;				/* dev.pcm.X.mode sysctl */
+	int f_default;				/* default mixer flag */
+};
+
+__BEGIN_DECLS
+
+struct mixer *mixer_open(const char *);
+int mixer_close(struct mixer *);
+struct mix_dev *mixer_get_dev(struct mixer *, int);
+struct mix_dev *mixer_get_dev_byname(struct mixer *, const char *);
+int mixer_add_ctl(struct mix_dev *, int, const char *,
+    int (*)(struct mix_dev *, void *), int (*)(struct mix_dev *, void *));
+int mixer_add_ctl_s(mix_ctl_t *);
+int mixer_remove_ctl(mix_ctl_t *);
+mix_ctl_t *mixer_get_ctl(struct mix_dev *, int);
+mix_ctl_t *mixer_get_ctl_byname(struct mix_dev *, const char *);
+int mixer_set_vol(struct mixer *, mix_volume_t);
+int mixer_set_mute(struct mixer *, int);
+int mixer_mod_recsrc(struct mixer *, int);
+int mixer_get_dunit(void);
+int mixer_set_dunit(struct mixer *, int);
+int mixer_get_mode(int);
+int mixer_get_nmixers(void);
+
+__END_DECLS
+
+#endif /* _MIXER_H_ */
diff --git a/usr.sbin/mixer/Makefile b/usr.sbin/mixer/Makefile
index dce135bc7891..6bbc6f07c7e1 100644
--- a/usr.sbin/mixer/Makefile
+++ b/usr.sbin/mixer/Makefile
@@ -2,10 +2,9 @@
 
 .include <src.opts.mk>
 
-PROG=	mixer
-MAN=	mixer.8
-
-HAS_TESTS=
-SUBDIR.${MK_TESTS}+= tests
+PROG=		mixer
+SRCS=		${PROG}.c
+MAN=		${PROG}.8
+LDFLAGS+=	-lmixer
 
 .include <bsd.prog.mk>
diff --git a/usr.sbin/mixer/mixer.8 b/usr.sbin/mixer/mixer.8
index 6e569cc8cfd9..39b30b53d529 100644
--- a/usr.sbin/mixer/mixer.8
+++ b/usr.sbin/mixer/mixer.8
@@ -1,76 +1,71 @@
-.\" Copyright (c) 1997
-.\"	Mike Pritchard <mpp@FreeBSD.org>.  All rights reserved.
+.\"-
+.\" Copyright (c) 2021 Christos Margiolis <christos@FreeBSD.org>
 .\"
-.\" 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.
-.\" 3. Neither the name of the author nor the names of its contributors
-.\"    may be used to endorse or promote products derived from this software
-.\"    without specific prior written permission.
+.\" Permission is hereby granted, free of charge, to any person obtaining a copy
+.\" of this software and associated documentation files (the "Software"), to deal
+.\" in the Software without restriction, including without limitation the rights
+.\" to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+.\" copies of the Software, and to permit persons to whom the Software is
+.\" furnished to do so, subject to the following conditions:
 .\"
-.\" THIS SOFTWARE IS PROVIDED BY MIKE PRITCHARD 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.
+.\" The above copyright notice and this permission notice shall be included in
+.\" all copies or substantial portions of the Software.
+.\"
+.\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+.\" IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+.\" FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+.\" AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+.\" LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+.\" OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+.\" THE SOFTWARE.
 .\"
 .\" $FreeBSD$
 .\"
-.Dd June 2, 2014
-.Dt MIXER 8
+
+.Dd June 30, 2021
+.Dt mixer 8
 .Os
 .Sh NAME
 .Nm mixer
-.Nd set/display soundcard mixer values
+.Nd manipulate soundcard mixer controls
 .Sh SYNOPSIS
 .Nm
 .Op Fl f Ar device
-.Op Fl s | S
-.Oo
-.Ar dev
-.Sm off
-.Oo
-.Op Cm + | -
-.Ar lvol
-.Op : Oo Cm + | - Oc Ar rvol
-.Oc
-.Oc
-.Sm on
-.Ar ...
-.Nm
-.Op Fl f Ar device
-.Op Fl s | S
-.Cm recsrc
+.Op Fl d Ar unit
+.Op Fl os
+.Op Ar dev Ns Op . Ns Ar control Ns Op = Ns Ar value
 .Ar ...
 .Nm
-.Op Fl f Ar device
-.Op Fl s | S
-.Sm off
-.Bro
-.Cm ^ | + | - | =
-.Brc
-.Cm rec
-.Sm on
-.Ar rdev ...
+.Op Fl d Ar unit
+.Op Fl os
+.Fl a
 .Sh DESCRIPTION
 The
 .Nm
-utility is used to set and display soundcard mixer device levels.
-It may
-also be used to start and stop recording from the soundcard.
-The list
-of mixer devices that may be modified are:
+utility is used to set and display soundcard mixer device controls.
+.Pp
+The options are as follows:
+.Bl -tag -width "-f device"
+.It Fl a
+Print the values for all mixer devices available in the system (see FILES).
+.It Fl d Ar unit
+Change the default audio card to
+.Ar unit .
+The unit has to be an integer value. To see what unit values are available, look
+at the number each mixer device has by running
+.Nm .
+.It Fl f Ar device
+Open
+.Ar device
+as the mixer device (see FILES).
+.It Fl o
+Print mixer values in a format suitable for use inside scripts. The
+mixer's header (name, audio card name, ...) will not be printed.
+.It Fl s
+Print only the recording source(s) of the mixer device.
+.El
+.Pp
+The list of mixer devices that may be modified are:
 .Bd -ragged -offset indent
 vol, bass, treble, synth, pcm, speaker, line, mic, cd, mix,
 pcm2, rec, igain, ogain, line1, line2, line3, dig1, dig2, dig3,
@@ -81,101 +76,170 @@ Not all mixer devices are available.
 .Pp
 Without any arguments,
 .Nm
-displays the current settings for all supported devices, followed by information
-about the current recording input devices.
+displays all information for each one of the mixer's supported devices to
+.Ar stdout .
 If the
 .Ar dev
 argument is specified,
 .Nm
-displays only the value for that
+displays only the values for
 .Ar dev .
+More than one device may be specified.
+.Pp
+Commands use the following format:
+.Pp
+.Bl -column xxxxxxxxxxxxxxxxxxxxxxxx -offset indent
+.It Sy "Name	Action"
+.It "dev	Display all controls"
+.It "dev.control	Display only the specified control"
+.It "dev.control=value	Set control value"
+.El
+.Pp
+The available controls are as follows (replace
+.Ar dev
+with one of the available devices):
+.Bl -column xxxxxxxxxxxxxxxxxxxxxxxx -offset indent
+.It Sy "Name	Value"
+.It "dev.volume	[[+|-]lvol[:[+|-]rvol]]"
+.It "dev.mute	{0|1|^}"
+.It "dev.recsrc	{+|-|^|=}"
+.El
 .Pp
-To modify the mixer value
-.Ar dev ,
-the optional left and right channel settings of
-.Ar lvol Ns Op : Ns Ar rvol
-may be specified.
 The
+.Ar dev.volume
+control modifies a device's volume. The optional
 .Ar lvol
-and
+and/or
 .Ar rvol
-arguments may be from 0 - 100.
-Omitting
-.Ar dev
-and including only the channel settings will change the main volume level.
-.Pp
-If the left or right channel settings are prefixed with
+values have to be specified. The values have to be normalized 32-bit floats,
+from 0.0 to 1.0 inclusivly. If no "." character is present, the value is treated
+like a percentage, for backwards compatibility.
+If the the left or right volume values are prefixed with
 .Cm +
 or
 .Cm - ,
 the value following will be used as a relative adjustment, modifying the
 current settings by the amount specified.
 .Pp
-If the
-.Fl s
-flag is used, the current mixer values will be displayed in a format suitable
-for use as the command-line arguments to a future invocation of
-.Nm
-(as above).
-.Pp
 The
-.Fl S
-flag provides the above output without mixing field separators.
+.Ar dev.mute
+control (un)mutes a device. The following values are available:
+.Bl -tag -width = -offset indent
+.It Cm 0
+unmutes
+.Ar dev .
+.It Cm 1
+mutes
+.Ar dev .
+.It Cm ^
+toggles the mute of
+.Ar dev .
+.El
 .Pp
-To change the recording device you use one of:
-.Bl -tag -width =rec -offset indent
-.It Cm ^rec
+The
+.Ar dev.recsrc
+control modifies the recording sources of a mixer.
+.Nm
+marks devices which can be used as a recording source with
+.Ar rec .
+Recording sources are marked with
+.Ar src .
+To modify the recording source you can use one of the following modifiers
+on a
+.Ar rec
+device:
+.Bl -tag -width = -offset indent
+.It Cm ^
 toggles
-.Ar rdev
+.Ar dev
 of possible recording devices
-.It Cm +rec
+.It Cm +
 adds
-.Ar rdev
+.Ar dev
 to possible recording devices
-.It Cm -rec
+.It Cm -
 removes
-.Ar rdev
+.Ar dev
 from possible recording devices
-.It Cm =rec
+.It Cm =
 sets the recording device to
-.Ar rdev
+.Ar dev
 .El
+.Sh FILES
+.Bl -tag -width /dev/mixerN -compact
+.It Pa /dev/mixerN
+The mixer device, where
+.Ar N
+is the number of that device, for example
+.Ar /dev/mixer0 .
+PCM cards and mixers have a 1:1 relationship, which means that
+.Ar mixer0
+is the mixer for
+.Ar pcm0
+and so on. By default,
+.Nm
+prints both the audio card's number and the mixer associated with it
+in the form of
+.Ar pcmN:mixer .
+The
+.Ar /dev/mixer
+file, although it doesn't exist in the filesystem, points to the default
+mixer device and is the file
+.Nm
+opens when the
+.Fl f Ar device
+option has not been specified.
+.El
+.Sh EXAMPLES
 .Pp
-The above commands work on an internal mask.
-After all the options
-have been parsed, it will set then read the mask from the sound card.
-This will let you see EXACTLY what the soundcard is using for the
-recording device(s).
+Change the volume for the
+.Ar vol
+device of the
+.Ar /dev/mixer0
+mixer device to 0.65:
+.Bl -tag -width Ds -offset indent
+.It $ mixer -f /dev/mixer0 vol.volume=0.65
+.El
 .Pp
-The option recsrc will display the current recording devices.
+Increase the
+.Ar mic
+device's left volume by 0.10 and decrease the right
+volume by 0.05:
+.Bl -tag -width Ds -offset indent
+.It $ mixer mic.volume=+0.10:-0.05
+.El
 .Pp
-The option
-.Fl f
-.Ar device
-will open
-.Ar device
-as the mixer device.
-.Sh FILES
-.Bl -tag -width /dev/mixer -compact
-.It Pa /dev/mixer
-the default mixer device
+Toggle the mute for
+.Ar vol :
+.Bl -tag -width Ds -offset indent
+.It $ mixer vol.mute=^
+.El
+.Pp
+Set
+.Ar mic
+and toggle
+.Ar line
+recording sources:
+.Bl -tag -width Ds -offset indent
+.It $ mixer mic.recsrc=+ line.recsrc=^
+.El
+.Pp
+Dump
+.Ar /dev/mixer0
+information to a file and retrieve back later
+.Bl -tag -width Ds -offset indent
+.It $ mixer -f /dev/mixer0 -o > info
+.It ...
+.It $ mixer -f /dev/mixer0 `cat info`
 .El
 .Sh SEE ALSO
-.Xr cdcontrol 1 ,
-.Xr sound 4
+.Xr mixer 3 ,
+.Xr sound 4 ,
+.Xr sysctl 8
 .Sh HISTORY
 The
 .Nm
-utility first appeared in
-.Fx 2.0.5 .
+utility first appeared in FreeBSD 2.0.5 and was rewritten completely in
+FreeBSD 12.2. \" FIXME: replace 12.2 with proper version.
 .Sh AUTHORS
-.An -nosplit
-Original source by
-.An Craig Metz Aq Mt cmetz@thor.tjhsst.edu
-and
-.An Hannu Savolainen .
-Mostly rewritten by
-.An John-Mark Gurney Aq Mt jmg@FreeBSD.org .
-This
-manual page was written by
-.An Mike Pritchard Aq Mt mpp@FreeBSD.org .
+.An Christos Margiolis Aq Mt christos@margiolis.net
diff --git a/usr.sbin/mixer/mixer.c b/usr.sbin/mixer/mixer.c
index 23193f22324b..3bbb8eebf93f 100644
--- a/usr.sbin/mixer/mixer.c
+++ b/usr.sbin/mixer/mixer.c
@@ -1,341 +1,484 @@
-/*
- *	This is an example of a mixer program for Linux
+/*-
+ * Copyright (c) 2021 Christos Margiolis <christos@FreeBSD.org>
  *
- *	updated 1/1/93 to add stereo, level query, broken
- *      	devmask kludge - cmetz@thor.tjhsst.edu
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
  *
- * (C) Craig Metz and Hannu Savolainen 1993.
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
  *
- * You may do anything you wish with this program.
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
  *
- * ditto for my modifications (John-Mark Gurney, 1997)
+ * $FreeBSD$
  */
 
-#include <sys/cdefs.h>
-__FBSDID("$FreeBSD$");
-
 #include <err.h>
-#include <fcntl.h>
-#include <libgen.h>
-#include <limits.h>
+#include <errno.h>
 #include <stdio.h>
-#include <string.h>
 #include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
-#include <sys/soundcard.h>
-
-static const char *names[SOUND_MIXER_NRDEVICES] = SOUND_DEVICE_NAMES;
 
-static void	usage(int devmask, int recmask) __dead2;
-static int	res_name(const char *name, int mask);
-static void	print_recsrc(int recsrc, int recmask, int sflag);
+#include <mixer.h>
+
+static void usage(void) __dead2;
+static void initctls(struct mixer *);
+static void printall(struct mixer *, int);
+static void printminfo(struct mixer *, int);
+static void printdev(struct mixer *, int);
+static void printrecsrc(struct mixer *, int); /* XXX: change name */
+/* Control handlers */
+static int mod_dunit(struct mix_dev *, void *);
+static int mod_volume(struct mix_dev *, void *);
+static int mod_mute(struct mix_dev *, void *);
+static int mod_recsrc(struct mix_dev *, void *);
+static int print_volume(struct mix_dev *, void *);
+static int print_mute(struct mix_dev *, void *);
+static int print_recsrc(struct mix_dev *, void *);
+
+static const mix_ctl_t ctl_dunit = {
+	.parent_dev	= NULL,
+	.id		= -1,
+	.name		= "default_unit",
+	.mod		= mod_dunit,
+	.print		= NULL
+};
 
-static void __dead2
-usage(int devmask, int recmask)
+int
+main(int argc, char *argv[])
 {
-	int	i, n;
-
-	printf("usage: mixer [-f device] [-s | -S] [dev [+|-][voll[:[+|-]volr]] ...\n"
-	    "       mixer [-f device] [-s | -S] recsrc ...\n"
-	    "       mixer [-f device] [-s | -S] {^|+|-|=}rec rdev ...\n");
-	if (devmask != 0) {
-		printf(" devices: ");
-		for (i = 0, n = 0; i < SOUND_MIXER_NRDEVICES; i++)
-			if ((1 << i) & devmask)  {
-				if (n)
-					printf(", ");
-				printf("%s", names[i]);
-				n++;
-			}
+	struct mixer *m;
+	mix_ctl_t *cp;
+	char *name = NULL, buf[NAME_MAX];
+	char *p, *bufp, *devstr, *ctlstr, *valstr = NULL;
+	int dunit, i, n, pall = 1;
+	int aflag = 0, dflag = 0, oflag = 0, sflag = 0;
+	char ch;
+
+	while ((ch = getopt(argc, argv, "ad:f:os")) != -1) {
+		switch (ch) {
+		case 'a':
+			aflag = 1;
+			break;
+		case 'd':
+			dunit = strtol(optarg, NULL, 10);
+			if (errno == EINVAL || errno == ERANGE)
+				err(1, "strtol");
+			dflag = 1;
+			break;
+		case 'f':
+			name = optarg;
+			break;
+		case 'o':
+			oflag = 1;
+			break;
+		case 's':
+			sflag = 1;
+			break;
+		case '?':
+		default:
+			usage();
+		}
 	}
-	if (recmask != 0) {
-		printf("\n rec devices: ");
-		for (i = 0, n = 0; i < SOUND_MIXER_NRDEVICES; i++)
-			if ((1 << i) & recmask)  {
-				if (n)
-					printf(", ");
-				printf("%s", names[i]);
-				n++;
+	argc -= optind;
+	argv += optind;
+
+	/* Print all mixers and exit. */
+	if (aflag) {
+		if ((n = mixer_get_nmixers()) < 0)
+			err(1, "mixer_get_nmixers");
+		for (i = 0; i < n; i++) {
+			(void)snprintf(buf, sizeof(buf), "/dev/mixer%d", i);
+			if ((m = mixer_open(buf)) == NULL)
+				err(1, "mixer_open: %s", buf);
+			initctls(m);
+			if (sflag)
+				printrecsrc(m, oflag);
+			else {
+				printall(m, oflag);
+				if (oflag)
+					printf("\n");
 			}
+			(void)mixer_close(m);
+		}
+		return (0);
 	}
-	printf("\n");
+
+	if ((m = mixer_open(name)) == NULL)
+		err(1, "mixer_open: %s", name);
+
+	initctls(m);
+
+	if (dflag && ctl_dunit.mod(m->dev, &dunit) < 0)
+		goto parse;
+	if (sflag) {
+		printrecsrc(m, oflag);
+		(void)mixer_close(m);
+		return (0);
+	}
+
+parse:
+	while (argc > 0) {
+		if ((p = bufp = strdup(*argv)) == NULL)
+			err(1, "strdup(%s)", *argv);
+		/* Split the string into device, control and value. */
+		devstr = strsep(&p, ".");
+		if ((m->dev = mixer_get_dev_byname(m, devstr)) == NULL) {
+			warnx("%s: no such device", devstr);
+			goto next;
+		}
+		/* Input: `dev`. */
+		if (p == NULL) {
+			printdev(m, 1);
+			pall = 0;
+			goto next;
+		}
+		ctlstr = strsep(&p, "=");
+		if ((cp = mixer_get_ctl_byname(m->dev, ctlstr)) == NULL) {
+			warnx("%s.%s: no such control", devstr, ctlstr);
+			goto next;
+		}
+
+		/* Input: `dev.control`. */
+		if (p == NULL) {
+			(void)cp->print(cp->parent_dev, cp->name);
+			pall = 0;
+			goto next;
+		}
+		valstr = p;
+		/* Input: `dev.control=val`. */
+		cp->mod(cp->parent_dev, valstr);
+next:
+		free(p);
+		argc--;
+		argv++;
+	}
+
+	if (pall)
+		printall(m, oflag);
+	(void)mixer_close(m);
+
+	return (0);
+}
+
+static void __dead2
+usage(void)
+{
+	printf("usage: %1$s [-f device] [-d unit] [-os] [dev[.control[=value]]] ...\n"
+	    "       %1$s [-d unit] [-os] -a\n",
+	    getprogname());
 	exit(1);
 }
 
-static int
-res_name(const char *name, int mask)
+static void
+initctls(struct mixer *m)
 {
-	int	foo;
+	struct mix_dev *dp;
+	int rc = 0;
+
+#define C_VOL 0
+#define C_MUT 1
+#define C_SRC 2
+	TAILQ_FOREACH(dp, &m->devs, devs) {
+		rc += mixer_add_ctl(dp, C_VOL, "volume", mod_volume, print_volume);
+		rc += mixer_add_ctl(dp, C_MUT, "mute", mod_mute, print_mute);
+		rc += mixer_add_ctl(dp, C_SRC, "recsrc", mod_recsrc, print_recsrc);
+	}
+	if (rc) {
+		(void)mixer_close(m);
+		err(1, "cannot make controls");
+	}
+}
 
-	for (foo = 0; foo < SOUND_MIXER_NRDEVICES; foo++)
-		if ((1 << foo) & mask && strcmp(names[foo], name) == 0)
-			break;
+static void
+printall(struct mixer *m, int oflag)
+{
+	struct mix_dev *dp;
 
-	return (foo == SOUND_MIXER_NRDEVICES ? -1 : foo);
+	printminfo(m, oflag);
+	TAILQ_FOREACH(dp, &m->devs, devs) {
+		m->dev = dp;
+		printdev(m, oflag);
+	}
 }
 
 static void
-print_recsrc(int recsrc, int recmask, int sflag)
+printminfo(struct mixer *m, int oflag)
 {
-	int	i, n;
+	int playrec = MIX_MODE_PLAY | MIX_MODE_REC;
 
-	if (recmask == 0)
+	if (oflag)
 		return;
+	printf("%s: <%s> %s", m->mi.name, m->ci.longname, m->ci.hw_info);
+	printf(" (");
+	if (m->mode & MIX_MODE_PLAY)
+		printf("play");
+	if ((m->mode & playrec) == playrec)
+		printf("/");
+	if (m->mode & MIX_MODE_REC)
+		printf("rec");
+	printf(")");
+	if (m->f_default)
+		printf(" (default)");
+	printf("\n");
+}
 
-	if (!sflag)
-		printf("Recording source: ");
+static void
+printdev(struct mixer *m, int oflag)
+{
+	struct mix_dev *d = m->dev;
+	mix_ctl_t *cp;
+
+	if (!oflag) {
+		char buffer[32];
+		(void)snprintf(buffer, sizeof(buffer),
+		    "%s.%s", d->name, "volume");
+
+		printf("    %-16s= %.2f:%.2f\t",
+		    buffer, d->vol.left, d->vol.right);
+		if (!MIX_ISREC(m, d->devno))
+			printf(" pbk");
+		if (MIX_ISREC(m, d->devno))
+			printf(" rec");
+		if (MIX_ISRECSRC(m, d->devno))
+			printf(" src");
+		if (MIX_ISMUTE(m, d->devno))
+			printf(" mute");
+		printf("\n");
+	} else {
+		TAILQ_FOREACH(cp, &d->ctls, ctls) {
+			(void)cp->print(cp->parent_dev, cp->name);
+		}
+	}
+}
 
-	for (i = 0, n = 0; i < SOUND_MIXER_NRDEVICES; i++)
-		if ((1 << i) & recsrc) {
-			if (sflag)
-				printf("%srec ", n ? " +" : "=");
-			else if (n)
+static void
+printrecsrc(struct mixer *m, int oflag)
+{
+	struct mix_dev *dp;
+	int n = 0;
+
+	if (!m->recmask)
+		return;
+	if (!oflag)
+		printf("%s: ", m->mi.name);
+	TAILQ_FOREACH(dp, &m->devs, devs) {
+		if (MIX_ISRECSRC(m, dp->devno)) {
+			if (n++ && !oflag)
 				printf(", ");
-			printf("%s", names[i]);
-			n++;
+			printf("%s", dp->name);
+			if (oflag)
+				printf(".%s=+%s",
+				    mixer_get_ctl(dp, C_SRC)->name,
+				    n ? " " : "");
 		}
-	if (!sflag)
-		printf("\n");
+	}
+	printf("\n");
 }
 
-int
-main(int argc, char *argv[])
+static int
+mod_dunit(struct mix_dev *d, void *p)
 {
-	char	mixer[PATH_MAX] = "/dev/mixer";
-	char	lstr[8], rstr[8];
-	char	*name, *eptr;
-	int	devmask = 0, recmask = 0, recsrc = 0, orecsrc;
-	int	dusage = 0, drecsrc = 0, sflag = 0, Sflag = 0;
-	int	l, r, lrel, rrel;
-	int	ch, foo, bar, baz, dev, m, n, t;
-
-	if ((name = strdup(basename(argv[0]))) == NULL)
-		err(1, "strdup()");
-	if (strncmp(name, "mixer", 5) == 0 && name[5] != '\0') {
-		n = strtol(name + 5, &eptr, 10) - 1;
-		if (n > 0 && *eptr == '\0')
-			snprintf(mixer, PATH_MAX - 1, "/dev/mixer%d", n);
-	}
-	free(name);
-	name = mixer;
+	int dunit = *((int *)p);
+	int n;
 
-	n = 1;
-	for (;;) {
-		if (n >= argc || *argv[n] != '-')
-			break;
-		if (strlen(argv[n]) != 2) {
-			if (strcmp(argv[n] + 1, "rec") != 0)
-				dusage = 1;
-			break;
-		}
-		ch = *(argv[n] + 1);
-		if (ch == 'f' && n < argc - 1) {
-			name = argv[n + 1];
-			n += 2;
-		} else if (ch == 's') {
-			sflag = 1;
-			n++;
-		} else if (ch == 'S') {
-			Sflag = 1;
-			n++;
-		} else {
-			dusage = 1;
-			break;
-		}
+	if ((n = mixer_get_dunit()) < 0) {
+		warn("cannot get default unit");
+		return (-1);
 	}
-	if (sflag && Sflag)
-		dusage = 1;
-
-	argc -= n - 1;
-	argv += n - 1;
-
-	if ((baz = open(name, O_RDWR)) < 0)
-		err(1, "%s", name);
-	if (ioctl(baz, SOUND_MIXER_READ_DEVMASK, &devmask) == -1)
-		err(1, "SOUND_MIXER_READ_DEVMASK");
-	if (ioctl(baz, SOUND_MIXER_READ_RECMASK, &recmask) == -1)
-		err(1, "SOUND_MIXER_READ_RECMASK");
-	if (ioctl(baz, SOUND_MIXER_READ_RECSRC, &recsrc) == -1)
-		err(1, "SOUND_MIXER_READ_RECSRC");
-	orecsrc = recsrc;
-
-	if (argc == 1 && dusage == 0) {
-		for (foo = 0, n = 0; foo < SOUND_MIXER_NRDEVICES; foo++) {
-			if (!((1 << foo) & devmask))
-				continue;
-			if (ioctl(baz, MIXER_READ(foo),&bar) == -1) {
-			   	warn("MIXER_READ");
-				continue;
-			}
-			if (Sflag || sflag) {
-				printf("%s%s%c%d:%d", n ? " " : "",
-				    names[foo], Sflag ? ':' : ' ',
-				    bar & 0x7f, (bar >> 8) & 0x7f);
-				n++;
-			} else
-				printf("Mixer %-8s is currently set to "
-				    "%3d:%d\n", names[foo], bar & 0x7f,
-				    (bar >> 8) & 0x7f);
-		}
-		if (n && recmask)
-			printf(" ");
-		print_recsrc(recsrc, recmask, Sflag || sflag);
-		return (0);
+	if (mixer_set_dunit(d->parent_mixer, dunit) < 0) {
+		warn("cannot set default unit to: %d", dunit);
+		return (-1);
 	}
+	printf("%s: %d -> %d\n", ctl_dunit.name, n, dunit);
 
-	argc--;
-	argv++;
-
-	n = 0;
-	while (argc > 0 && dusage == 0) {
-		if (strcmp("recsrc", *argv) == 0) {
-			drecsrc = 1;
-			argc--;
-			argv++;
-			continue;
-		} else if (strcmp("rec", *argv + 1) == 0) {
-			if (**argv != '+' && **argv != '-' &&
-			    **argv != '=' && **argv != '^') {
-				warnx("unknown modifier: %c", **argv);
-				dusage = 1;
-				break;
-			}
-			if (argc <= 1) {
-				warnx("no recording device specified");
-				dusage = 1;
-				break;
-			}
-			if ((dev = res_name(argv[1], recmask)) == -1) {
-				warnx("unknown recording device: %s", argv[1]);
-				dusage = 1;
-				break;
-			}
-			switch (**argv) {
-			case '+':
-				recsrc |= (1 << dev);
-				break;
-			case '-':
-				recsrc &= ~(1 << dev);
-				break;
-			case '=':
-				recsrc = (1 << dev);
-				break;
-			case '^':
-				recsrc ^= (1 << dev);
-				break;
-			}
-			drecsrc = 1;
-			argc -= 2;
-			argv += 2;
-			continue;
-		}
-
-		if ((t = sscanf(*argv, "%d:%d", &l, &r)) > 0)
-			dev = 0;
-		else if ((dev = res_name(*argv, devmask)) == -1) {
-			warnx("unknown device: %s", *argv);
-			dusage = 1;
-			break;
-		}
+	return (0);
+}
 
-		lrel = rrel = 0;
-		if (argc > 1) {
-			m = sscanf(argv[1], "%7[^:]:%7s", lstr, rstr);
-			if (m == EOF) {
-				warnx("invalid value: %s", argv[1]);
-				dusage = 1;
-				break;
-			}
-			if (m > 0) {
-				if (*lstr == '+' || *lstr == '-')
-					lrel = rrel = 1;
-				l = strtol(lstr, NULL, 10);
-			}
-			if (m > 1) {
-				if (*rstr == '+' || *rstr == '-')
-					rrel = 1;
-				r = strtol(rstr, NULL, 10);
-			}
-		}
+static int
+mod_volume(struct mix_dev *d, void *p)
+{
+	struct mixer *m;
+	mix_ctl_t *cp;
+	mix_volume_t v;
+	const char *val;
+	char lstr[8], rstr[8];
+	float lprev, rprev, lrel, rrel;
+	int n;
+
+	m = d->parent_mixer;
+	cp = mixer_get_ctl(m->dev, C_VOL);
+	val = p;
+	n = sscanf(val, "%7[^:]:%7s", lstr, rstr);
+	if (n == EOF) {
+		warnx("invalid volume value: %s", val);
+		return (-1);
+	}
+	lrel = rrel = 0;
+	if (n > 0) {
+		if (*lstr == '+' || *lstr == '-')
+			lrel = rrel = 1;
+		v.left = strtof(lstr, NULL);
+
+		/* be backwards compatible */
+		if (strstr(lstr, ".") == NULL)
+			v.left /= 100.0f;
+	}
+	if (n > 1) {
+		if (*rstr == '+' || *rstr == '-')
+			rrel = 1;
+		v.right = strtof(rstr, NULL);
+
+		/* be backwards compatible */
+		if (strstr(rstr, ".") == NULL)
+			v.right /= 100.0f;
+	}
+	switch (n) {
+	case 1:
+		v.right = v.left; /* FALLTHROUGH */
+	case 2:
+		if (lrel)
+			v.left += m->dev->vol.left;
+		if (rrel)
+			v.right += m->dev->vol.right;
+
+		if (v.left < MIX_VOLMIN)
+			v.left = MIX_VOLMIN;
+		else if (v.left > MIX_VOLMAX)
+			v.left = MIX_VOLMAX;
+		if (v.right < MIX_VOLMIN)
+			v.right = MIX_VOLMIN;
+		else if (v.right > MIX_VOLMAX)
+			v.right = MIX_VOLMAX;
+
+		lprev = m->dev->vol.left;
+		rprev = m->dev->vol.right;
+		if (mixer_set_vol(m, v) < 0)
+			warn("%s.%s=%.2f:%.2f",
+			    m->dev->name, cp->name, v.left, v.right);
+		else
+			printf("%s.%s: %.2f:%.2f -> %.2f:%.2f\n",
+			   m->dev->name, cp->name, lprev, rprev, v.left, v.right);
+	}
 
-		switch (argc > 1 ? m : t) {
-		case 0:
-			if (ioctl(baz, MIXER_READ(dev), &bar) == -1) {
-				warn("MIXER_READ");
-				argc--;
-				argv++;
-				continue;
-			}
-			if (Sflag || sflag) {
-				printf("%s%s%c%d:%d", n ? " " : "",
-				    names[dev], Sflag ? ':' : ' ',
-				    bar & 0x7f, (bar >> 8) & 0x7f);
-				n++;
-			} else
-				printf("Mixer %-8s is currently set to "
-				    "%3d:%d\n", names[dev], bar & 0x7f,
-				    (bar >> 8) & 0x7f);
-
-			argc--;
-			argv++;
-			break;
-		case 1:
-			r = l;
-			/* FALLTHROUGH */
-		case 2:
-			if (ioctl(baz, MIXER_READ(dev), &bar) == -1) {
-				warn("MIXER_READ");
-				argc--;
-				argv++;
-				continue;
-			}
+	return (0);
+}
 
-			if (lrel)
-				l = (bar & 0x7f) + l;
-			if (rrel)
-				r = ((bar >> 8) & 0x7f) + r;
-
-			if (l < 0)
-				l = 0;
-			else if (l > 100)
-				l = 100;
-			if (r < 0)
-				r = 0;
-			else if (r > 100)
-				r = 100;
-
-			if (!Sflag)
-				printf("Setting the mixer %s from %d:%d to "
-				    "%d:%d.\n", names[dev], bar & 0x7f,
-				    (bar >> 8) & 0x7f, l, r);
-
-			l |= r << 8;
-			if (ioctl(baz, MIXER_WRITE(dev), &l) == -1)
-				warn("WRITE_MIXER");
-
-			argc -= 2;
-			argv += 2;
- 			break;
-		}
+static int
+mod_mute(struct mix_dev *d, void *p)
+{
+	struct mixer *m;
+	mix_ctl_t *cp;
+	const char *val;
+	int n, opt = -1;
+
+	m = d->parent_mixer;
+	cp = mixer_get_ctl(m->dev, C_MUT);
+	val = p;
+	switch (*val) {
+	case '0':
+		opt = MIX_UNMUTE;
+		break;
+	case '1':
+		opt = MIX_MUTE;
+		break;
+	case '^':
+		opt = MIX_TOGGLEMUTE;
+		break;
+	default:
+		warnx("%c: no such modifier", *val);
+		return (-1);
 	}
+	n = MIX_ISMUTE(m, m->dev->devno);
+	if (mixer_set_mute(m, opt) < 0)
+		warn("%s.%s=%c", m->dev->name, cp->name, *val);
+	else
+		printf("%s.%s: %d -> %d\n",
+		    m->dev->name, cp->name, n, MIX_ISMUTE(m, m->dev->devno));
 
-	if (dusage) {
-		close(baz);
-		usage(devmask, recmask);
-		/* NOTREACHED */
-	}
+	return (0);
+}
 
-	if (orecsrc != recsrc) {
-		if (ioctl(baz, SOUND_MIXER_WRITE_RECSRC, &recsrc) == -1)
-			err(1, "SOUND_MIXER_WRITE_RECSRC");
-		if (ioctl(baz, SOUND_MIXER_READ_RECSRC, &recsrc) == -1)
-			err(1, "SOUND_MIXER_READ_RECSRC");
+static int
+mod_recsrc(struct mix_dev *d, void *p)
+{
+	struct mixer *m;
+	mix_ctl_t *cp;
+	const char *val;
+	int n, opt = -1;
+
+	m = d->parent_mixer;
+	cp = mixer_get_ctl(m->dev, C_SRC);
+	val = p;
+	switch (*val) {
+	case '+':
+		opt = MIX_ADDRECSRC;
+		break;
+	case '-':
+		opt = MIX_REMOVERECSRC;
+		break;
+	case '=':
+		opt = MIX_SETRECSRC;
+		break;
+	case '^':
+		opt = MIX_TOGGLERECSRC;
+		break;
+	default:
+		warnx("%c: no such modifier", *val);
+		return (-1);
 	}
+	n = MIX_ISRECSRC(m, m->dev->devno);
+	if (mixer_mod_recsrc(m, opt) < 0)
+		warn("%s.%s=%c", m->dev->name, cp->name, *val);
+	else
+		printf("%s.%s: %d -> %d\n",
+		    m->dev->name, cp->name, n, MIX_ISRECSRC(m, m->dev->devno));
+
+	return (0);
+}
 
-	if (drecsrc)
-		print_recsrc(recsrc, recmask, Sflag || sflag);
+static int
+print_volume(struct mix_dev *d, void *p)
+{
+	struct mixer *m = d->parent_mixer;
+	const char *ctl_name = p;
+
+	printf("%s.%s=%.2f:%.2f\n",
+	    m->dev->name, ctl_name, m->dev->vol.left, m->dev->vol.right);
+
+	return (0);
+}
+
+static int
+print_mute(struct mix_dev *d, void *p)
+{
+	struct mixer *m = d->parent_mixer;
+	const char *ctl_name = p;
+
+	printf("%s.%s=%d\n", m->dev->name, ctl_name, MIX_ISMUTE(m, m->dev->devno));
+
+	return (0);
+}
+
+static int
+print_recsrc(struct mix_dev *d, void *p)
+{
+	struct mixer *m = d->parent_mixer;
+	const char *ctl_name = p;
 
-	close(baz);
+	if (!MIX_ISRECSRC(m, m->dev->devno))
+		return (-1);
+	printf("%s.%s=+\n", m->dev->name, ctl_name);
 
 	return (0);
 }
diff --git a/usr.sbin/mixer/tests/Makefile b/usr.sbin/mixer/tests/Makefile
deleted file mode 100644
index 032cab369f7e..000000000000
--- a/usr.sbin/mixer/tests/Makefile
+++ /dev/null
@@ -1,5 +0,0 @@
-# $FreeBSD$
-
-ATF_TESTS_SH+=		mixer_test
-
-.include <bsd.test.mk>
diff --git a/usr.sbin/mixer/tests/mixer_test.sh b/usr.sbin/mixer/tests/mixer_test.sh
deleted file mode 100755
index 1a1266553b3f..000000000000
--- a/usr.sbin/mixer/tests/mixer_test.sh
+++ /dev/null
@@ -1,123 +0,0 @@
-#
-# SPDX-License-Identifier: BSD-2-Clause-FreeBSD
-#
-# Copyright (c) 2019 Mateusz Piotrowski <0mp@FreeBSD.org>
-#
-# 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.
-
-# $FreeBSD$
-
-mixer_unavailable()
-{
-	! { mixer && mixer vol; } >/dev/null 2>&1
-}
-
-save_mixer_vol()
-{
-	atf_check -o match:'^[0-9]{1,3}:[0-9]{1,3}$' -o save:saved_vol \
-		-x "mixer vol | awk '{print \$7}'"
-}
-
-set_mixer_vol()
-{
-	atf_check \
-		-o match:'^Setting the mixer vol from [0-9]{1,3}:[0-9]{1,3} to 0:0\.$' \
-		mixer vol 0
-}
-
-restore_mixer_vol()
-{
-	if [ -r "saved_vol" ]; then
-		mixer vol "$(cat saved_vol)"
-	fi
-}
-
-atf_test_case s_flag cleanup
-s_flag_head()
-{
-	atf_set	"descr" "Verify that the output of the -s flag could be " \
-		"reused as command-line arguments to the mixer command"
-}
-s_flag_body()
-{
-	if mixer_unavailable; then
-		atf_skip "This test requires mixer support"
-	fi
-	save_mixer_vol
-	set_mixer_vol
-	atf_check -o inline:"vol 0:0" -o save:values mixer -s vol
-	atf_check -o inline:"Setting the mixer vol from 0:0 to 0:0.\n" \
-		mixer $(cat values)
-}
-s_flag_cleanup()
-{
-	restore_mixer_vol
-}
-
-atf_test_case S_flag cleanup
-S_flag_head()
-{
-	atf_set	"descr" "Verify that the output of the -S flag is " \
-		"matching the documented behavior"
-}
-S_flag_body()
-{
-	if mixer_unavailable; then
-		atf_skip "This test requires mixer support"
-	fi
-	save_mixer_vol
-	set_mixer_vol
-	atf_check -o inline:"vol:0:0" mixer -S vol
-}
-S_flag_cleanup()
-{
-	restore_mixer_vol
-}
-
-atf_test_case set_empty_value cleanup
-set_empty_value_head()
-{
-	atf_set	"descr" "Verify that mixer returns when the provided " \
-		"value to set is an empty string instead of a number"
-	atf_set "timeout" "1"
-}
-set_empty_value_body()
-{
-	if mixer_unavailable; then
-		atf_skip "This test requires mixer support"
-	fi
-	save_mixer_vol
-	atf_check -s exit:1 -e inline:"mixer: invalid value: \n" \
-		-o match:"^usage:" mixer vol ""
-}
-set_empty_value_cleanup()
-{
-	restore_mixer_vol
-}
-
-
-atf_init_test_cases()
-{
-	atf_add_test_case s_flag
-	atf_add_test_case S_flag
-	atf_add_test_case set_empty_value
-}