~saurabhs/slstatus

9ac721c23fb640de2a6d1f84c84a79b2ccc26691 — Ingo Feinerer 2 years ago aaf279f
Use the sioctl_open(3) OpenBSD API to access vol

Starting with OpenBSD 6.7 regular users cannot access raw audio devices
anymore, for improved security.

Instead use the sioctl_open(3) API to access and manipulate audio
controls exposed by sndiod(8). On the first call a permanent connection
is established with the running sndiod daemon, and call-back functions
are registered which are triggered when audio controls are changed
(e.g., a USB headset is attached) or when the volume is modified. On
subsequent calls we poll for changes; if there are no volume changes
this costs virtually nothing.

Joint work with Alexandre Ratchov
3 files changed, 161 insertions(+), 51 deletions(-)

M components/volume.c
M config.def.h
M config.mk
M components/volume.c => components/volume.c +159 -51
@@ 8,69 8,177 @@
#include "../util.h"

#if defined(__OpenBSD__)
	#include <sys/audioio.h>
	#include <sys/queue.h>
	#include <poll.h>
	#include <sndio.h>
	#include <stdlib.h>

	struct control {
		LIST_ENTRY(control)	next;
		unsigned int		addr;
	#define CTRL_NONE	0
	#define CTRL_LEVEL	1
	#define CTRL_MUTE	2
		unsigned int		type;
		unsigned int		maxval;
		unsigned int		val;
	};

	static LIST_HEAD(, control) controls = LIST_HEAD_INITIALIZER(controls);
	static struct pollfd *pfds;
	static struct sioctl_hdl *hdl;
	static int initialized;

	/*
	 * Call-back to obtain the description of all audio controls.
	 */
	static void
	ondesc(void *unused, struct sioctl_desc *desc, int val)
	{
		struct control *c, *ctmp;
		unsigned int type = CTRL_NONE;

		if (desc == NULL)
			return;

		/* Delete existing audio control with the same address. */
		LIST_FOREACH_SAFE(c, &controls, next, ctmp) {
			if (desc->addr == c->addr) {
				LIST_REMOVE(c, next);
				free(c);
				break;
			}
		}

		/* Only match output.level and output.mute audio controls. */
		if (desc->group[0] != 0 ||
		    strcmp(desc->node0.name, "output") != 0)
			return;
		if (desc->type == SIOCTL_NUM &&
		    strcmp(desc->func, "level") == 0)
			type = CTRL_LEVEL;
		else if (desc->type == SIOCTL_SW &&
			 strcmp(desc->func, "mute") == 0)
			type = CTRL_MUTE;
		else
			return;

		c = malloc(sizeof(struct control));
		if (c == NULL) {
			warn("sndio: failed to allocate audio control\n");
			return;
		}

		c->addr = desc->addr;
		c->type = type;
		c->maxval = desc->maxval;
		c->val = val;
		LIST_INSERT_HEAD(&controls, c, next);
	}

	/*
	 * Call-back invoked whenever an audio control changes.
	 */
	static void
	onval(void *unused, unsigned int addr, unsigned int val)
	{
		struct control *c;

		LIST_FOREACH(c, &controls, next) {
			if (c->addr == addr)
				break;
		}
		c->val = val;
	}

	static void
	cleanup(void)
	{
		struct control *c;

		if (hdl) {
			sioctl_close(hdl);
			hdl = NULL;
		}

		free(pfds);
		pfds = NULL;

		while (!LIST_EMPTY(&controls)) {
			c = LIST_FIRST(&controls);
			LIST_REMOVE(c, next);
			free(c);
		}
	}

	static int
	init(void)
	{
		hdl = sioctl_open(SIO_DEVANY, SIOCTL_READ, 0);
		if (hdl == NULL) {
			warn("sndio: cannot open device");
			goto failed;
		}

		if (!sioctl_ondesc(hdl, ondesc, NULL)) {
			warn("sndio: cannot set control description call-back");
			goto failed;
		}

		if (!sioctl_onval(hdl, onval, NULL)) {
			warn("sndio: cannot set control values call-back");
			goto failed;
		}

		pfds = calloc(sioctl_nfds(hdl), sizeof(struct pollfd));
		if (pfds == NULL) {
			warn("sndio: cannot allocate pollfd structures");
			goto failed;
		}

		return 1;
	failed:
		cleanup();
		return 0;
	}

	const char *
	vol_perc(const char *card)
	vol_perc(const char *unused)
	{
		static int cls = -1;
		mixer_devinfo_t mdi;
		mixer_ctrl_t mc;
		int afd = -1, m = -1, v = -1;
		struct control *c;
		int n, v, value;

		if ((afd = open(card, O_RDONLY)) < 0) {
			warn("open '%s':", card);
		if (!initialized)
			initialized = init();

		if (hdl == NULL)
			return NULL;
		}

		for (mdi.index = 0; cls == -1; mdi.index++) {
			if (ioctl(afd, AUDIO_MIXER_DEVINFO, &mdi) < 0) {
				warn("ioctl 'AUDIO_MIXER_DEVINFO':");
				close(afd);
				return NULL;
			}
			if (mdi.type == AUDIO_MIXER_CLASS &&
			    !strncmp(mdi.label.name,
				     AudioCoutputs,
				     MAX_AUDIO_DEV_LEN))
				cls = mdi.index;
			}
		for (mdi.index = 0; v == -1 || m == -1; mdi.index++) {
			if (ioctl(afd, AUDIO_MIXER_DEVINFO, &mdi) < 0) {
				warn("ioctl 'AUDIO_MIXER_DEVINFO':");
				close(afd);
				return NULL;
			}
			if (mdi.mixer_class == cls &&
			    ((mdi.type == AUDIO_MIXER_VALUE &&
			      !strncmp(mdi.label.name,
				       AudioNmaster,
				       MAX_AUDIO_DEV_LEN)) ||
			     (mdi.type == AUDIO_MIXER_ENUM &&
			      !strncmp(mdi.label.name,
				      AudioNmute,
				      MAX_AUDIO_DEV_LEN)))) {
				mc.dev = mdi.index, mc.type = mdi.type;
				if (ioctl(afd, AUDIO_MIXER_READ, &mc) < 0) {
					warn("ioctl 'AUDIO_MIXER_READ':");
					close(afd);
		n = sioctl_pollfd(hdl, pfds, POLLIN);
		if (n > 0) {
			n = poll(pfds, n, 0);
			if (n > 0) {
				if (sioctl_revents(hdl, pfds) & POLLHUP) {
					warn("sndio: disconnected");
					cleanup();
					return NULL;
				}
				if (mc.type == AUDIO_MIXER_VALUE)
					v = mc.un.value.num_channels == 1 ?
					    mc.un.value.level[AUDIO_MIXER_LEVEL_MONO] :
					    (mc.un.value.level[AUDIO_MIXER_LEVEL_LEFT] >
					     mc.un.value.level[AUDIO_MIXER_LEVEL_RIGHT] ?
					     mc.un.value.level[AUDIO_MIXER_LEVEL_LEFT] :
					     mc.un.value.level[AUDIO_MIXER_LEVEL_RIGHT]);
				else if (mc.type == AUDIO_MIXER_ENUM)
					m = mc.un.ord;
			}
		}

		close(afd);
		value = 100;
		LIST_FOREACH(c, &controls, next) {
			if (c->type == CTRL_MUTE && c->val == 1)
				value = 0;
			else if (c->type == CTRL_LEVEL) {
				v = (c->val * 100 + c->maxval / 2) / c->maxval;
				/* For multiple channels return the minimum. */
				if (v < value)
					value = v;
			}
		}

		return bprintf("%d", m ? 0 : v * 100 / 255);
		return bprintf("%d", value);
	}
#else
	#include <sys/soundcard.h>

M config.def.h => config.def.h +1 -0
@@ 59,6 59,7 @@ static const char unknown_str[] = "n/a";
 * uptime              system uptime                   NULL
 * username            username of current user        NULL
 * vol_perc            OSS/ALSA volume in percent      mixer file (/dev/mixer)
 *                                                     NULL on OpenBSD
 * wifi_perc           WiFi signal in percent          interface name (wlan0)
 * wifi_essid          WiFi ESSID                      interface name (wlan0)
 */

M config.mk => config.mk +1 -0
@@ 14,6 14,7 @@ X11LIB = /usr/X11R6/lib
CPPFLAGS = -I$(X11INC) -D_DEFAULT_SOURCE
CFLAGS   = -std=c99 -pedantic -Wall -Wextra -Os
LDFLAGS  = -L$(X11LIB) -s
# OpenBSD: add -lsndio
LDLIBS   = -lX11

# compiler and linker