extra/i3status/add-sndio-backend.patch

--- /dev/null
+++ src/sndio.c
@@ -0,0 +1,201 @@
+#include <poll.h>
+#include <sndio.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "i3status.h"
+
+struct control {
+    struct control *next;
+    char name[32];
+    unsigned int addr;
+    unsigned int max;
+    unsigned int value;
+    unsigned int muted;
+    unsigned int muteaddr;
+};
+
+static int initialized;
+static struct sioctl_hdl *hdl;
+static struct control *controls;
+static struct pollfd *pfds;
+
+/*
+ * new control registered or control changed
+ */
+static void ondesc(void *unused, struct sioctl_desc *d, int val)
+{
+    struct control *i, **pi;
+
+    if (d == NULL)
+        return;
+
+    /*
+     * delete existing control with the same address
+     */
+    for (pi = &controls; (i = *pi) != NULL; pi = &i->next) {
+        if (d->addr == i->addr) {
+            *pi = i->next;
+            free(i);
+            break;
+        }
+    }
+
+    /*
+     * if we find an output.mute, associate it with its output.level
+     */
+    if (d->type == SIOCTL_SW &&
+        d->group[0] == 0 &&
+        strcmp(d->node0.name, "output") == 0 &&
+        strcmp(d->func, "mute") == 0) {
+        char name[32];
+        snprintf(name, sizeof(name), "%s%d", d->node0.name, d->node0.unit);
+    	for (pi = &controls; (i = *pi) != NULL; pi = &i->next) {
+            if (strcmp(name, i->name) == 0) {
+                i->muted = val;
+                i->muteaddr = d->addr;
+                break;
+            }
+        }
+	return;
+    }
+
+    /*
+     * we're interested in top-level output.level controls only
+     */
+    if (d->type != SIOCTL_NUM ||
+        d->group[0] != 0 ||
+        strcmp(d->node0.name, "output") != 0 ||
+        strcmp(d->func, "level") != 0)
+        return;
+
+    i = malloc(sizeof(struct control));
+    if (i == NULL) {
+        fprintf(stderr, "sndio: failed to allocate control\n");
+        return;
+    }
+
+    snprintf(i->name, sizeof(i->name), "%s%d", d->node0.name, d->node0.unit);
+    i->addr = d->addr;
+    i->max = d->maxval;
+    i->value = val;
+    i->next = controls;
+    i->muted = 0;
+    i->muteaddr = -1;
+    controls = i;
+}
+
+/*
+ * control value changed
+ */
+static void onval(void *unused, unsigned int addr, unsigned int value)
+{
+    struct control *c;
+
+    for (c = controls; ; c = c->next) {
+        if (c == NULL)
+            return;
+        if (c->addr == addr) {
+            c->value = value;
+            return;
+        }
+        if (c->muteaddr == addr) {
+            c->muted = value;
+            return;
+        }
+    }
+}
+
+static void cleanup(void)
+{
+    struct control *c;
+
+    if (hdl) {
+        sioctl_close(hdl);
+        hdl = NULL;
+    }
+    if (pfds) {
+        free(pfds);
+        pfds = NULL;
+    }
+    while ((c = controls) != NULL) {
+        controls = c->next;
+        free(c);
+    }
+}
+
+static int init(void)
+{
+    /* open device */
+    hdl = sioctl_open(SIO_DEVANY, SIOCTL_READ, 0);
+    if (hdl == NULL) {
+        fprintf(stderr, "sndio: cannot open device\n");
+        goto failed;
+    }
+
+    /* register call-back for control description changes */
+    if (!sioctl_ondesc(hdl, ondesc, NULL)) {
+        fprintf(stderr, "sndio: cannot get description\n");
+        goto failed;
+    }
+
+    /* register call-back for volume changes */
+    if (!sioctl_onval(hdl, onval, NULL)) {
+        fprintf(stderr, "sndio: cannot get values\n");
+        goto failed;
+    }
+
+    /* allocate structures for poll() syscall */
+    pfds = calloc(sioctl_nfds(hdl), sizeof(struct pollfd));
+    if (pfds == NULL) {
+        fprintf(stderr, "sndio: cannot allocate pollfd structures\n");
+        goto failed;
+    }
+    return 1;
+failed:
+    cleanup();
+    return 0;
+}
+
+int volume_sndio(int *vol, int *muted)
+{
+    struct control *c;
+    int n, v;
+
+    if (!initialized) {
+        initialized = 1;
+        init();
+    }
+    if (hdl == NULL)
+        return -1;
+
+    /* check if controls changed */
+    n = sioctl_pollfd(hdl, pfds, POLLIN);
+    if (n > 0) {
+        n = poll(pfds, n, 0);
+        if (n > 0) {
+            if (sioctl_revents(hdl, pfds) & POLLHUP) {
+                fprintf(stderr, "sndio: disconnected\n");
+                cleanup();
+                return -1;
+            }
+        }
+    }
+
+    /*
+     * get control value: as there may be multiple
+     * channels, return the minimum
+     */
+    *vol = 100;
+    *muted = 0;
+    for (c = controls; c != NULL; c = c->next) {
+        v = (c->value * 100 + c->max / 2) / c->max;
+        if (v < *vol) {
+            *vol = v;
+            *muted = c->muted;
+
+        }
+    }
+
+    return 0;
+}
--- a/configure.ac
+++ b/configure.ac
@@ -91,6 +91,13 @@ case $host_os in
 	;;
 esac
 
+# if sndio is available, define USE_SNDIO
+AC_CHECK_HEADER(sndio.h,
+	[AC_CHECK_LIB([sndio], [sio_open], [
+		AC_SUBST(SNDIO_LIBS, "-lsndio")
+		AC_DEFINE([USE_SNDIO], [], [Use sndio])
+	], [])], [])
+
 dnl TODO: check for libbsd for GNU/kFreeBSD
 
 # Checks for programs.
--- a/include/i3status.h
+++ b/include/i3status.h
@@ -425,6 +425,7 @@ void print_volume(volume_ctx_t *ctx);
 
 bool process_runs(const char *path);
 int volume_pulseaudio(uint32_t sink_idx, const char *sink_name);
+int volume_sndio(int *vol, int *muted);
 bool description_pulseaudio(uint32_t sink_idx, const char *sink_name, char buffer[MAX_SINK_DESCRIPTION_LEN]);
 bool pulse_initialize(void);