diff --git a/libsndio/amsg.h b/libsndio/amsg.h
index 0b3c2e9..fa276a5 100644
--- a/libsndio/amsg.h
+++ b/libsndio/amsg.h
@@ -19,12 +19,28 @@
 
 #include <stdint.h>
 
-/*
- * socket and option names
+/* 
+ * unix-domain socket name is:
+ *
+ * DIR [ '-' UID ] '/' FILE UNIT
+ *
+ * example: "/tmp/aucat-1000/aucat0"
+ *
+ */
+#define SOCKPATH_DIR	"/tmp/aucat"
+#define SOCKPATH_FILE	"aucat"
+#define SOCKPATH_MAX	(1 +		\
+	sizeof(SOCKPATH_DIR) - 1 +	\
+	sizeof(char) +			\
+	sizeof(int) * 3 +		\
+	sizeof(char) +			\
+	sizeof(SOCKPATH_FILE) - 1 +	\
+	sizeof(int) * 3)
+
+/*
+ * server TCP base port number
  */
-#define AUCAT_PATH		"aucat"
 #define AUCAT_PORT		11025
-#define DEFAULT_OPT		"default"
 
 /*
  * WARNING: since the protocol may be simultaneously used by static
diff --git a/libsndio/aucat.c b/libsndio/aucat.c
index 6dd88c4..c6a3ac2 100644
--- a/libsndio/aucat.c
+++ b/libsndio/aucat.c
@@ -244,10 +244,12 @@ _aucat_wdata(struct aucat *hdl, const void *buf, size_t len,
 static int
 aucat_mkcookie(unsigned char *cookie)
 {
+#define COOKIE_SUFFIX	"/.aucat_cookie"
+#define TEMPL_SUFFIX	".XXXXXXXX"
 	struct stat sb;
-	char *home, path[PATH_MAX], tmp[PATH_MAX];
-	ssize_t len;
-	int fd;
+	char *home, *path = NULL, *tmp = NULL;
+	size_t home_len, path_len;
+	int fd, len;
 
 	/*
 	 * try to load the cookie
@@ -255,7 +257,13 @@ aucat_mkcookie(unsigned char *cookie)
 	home = issetugid() ? NULL : getenv("HOME");
 	if (home == NULL)
 		goto bad_gen;
-	snprintf(path, PATH_MAX, "%s/.aucat_cookie", home);
+	home_len = strlen(home);
+	path = malloc(home_len + sizeof(COOKIE_SUFFIX));
+	if (path == NULL)
+		goto bad_gen;
+	memcpy(path, home, home_len);
+	memcpy(path + home_len, COOKIE_SUFFIX, sizeof(COOKIE_SUFFIX));
+	path_len = home_len + sizeof(COOKIE_SUFFIX) - 1;
 	fd = open(path, O_RDONLY);
 	if (fd < 0) {
 		if (errno != ENOENT)
@@ -280,7 +288,7 @@ aucat_mkcookie(unsigned char *cookie)
 		goto bad_close;
 	}
 	close(fd);
-	return 1;
+	goto done;
 bad_close:
 	close(fd);
 bad_gen:
@@ -290,36 +298,44 @@ bad_gen:
 #ifdef HAVE_ARC4RANDOM
 	arc4random_buf(cookie, AMSG_COOKIELEN);
 #else
-	if (!random_bytes(cookie, AMSG_COOKIELEN))
+	if (!random_bytes(cookie, AMSG_COOKIELEN)) {
+		if (path)
+			free(path);
 		return 0;
+	}
 #endif
 
 	/*
 	 * try to save the cookie
 	 */
 	if (home == NULL)
-		return 1;
-	if (strlcpy(tmp, path, PATH_MAX) >= PATH_MAX ||
-	    strlcat(tmp, ".XXXXXXXX", PATH_MAX) >= PATH_MAX) {
-		DPRINTF("%s: too long\n", path);
-		return 1;
-	}
+		goto done;
+	tmp = malloc(path_len + sizeof(TEMPL_SUFFIX));
+	if (tmp == NULL)
+		goto done;
+	memcpy(tmp, path, path_len);
+	memcpy(tmp + path_len, TEMPL_SUFFIX, sizeof(TEMPL_SUFFIX));
 	fd = mkstemp(tmp);
 	if (fd < 0) {
 		DPERROR(tmp);
-		return 1;
+		goto done;
 	}
 	if (write(fd, cookie, AMSG_COOKIELEN) < 0) {
 		DPERROR(tmp);
 		unlink(tmp);
 		close(fd);
-		return 1;
+		goto done;
 	}
 	close(fd);
 	if (rename(tmp, path) < 0) {
 		DPERROR(tmp);
 		unlink(tmp);
 	}
+done:
+	if (tmp)
+		free(tmp);
+	if (path)
+		free(path);
 	return 1;
 }
 
@@ -381,7 +397,7 @@ aucat_connect_un(struct aucat *hdl, unsigned int unit)
 
 	uid = geteuid();
 	snprintf(ca.sun_path, sizeof(ca.sun_path),
-	    "/tmp/aucat-%u/%s%u", uid, AUCAT_PATH, unit);
+	    SOCKPATH_DIR "-%u/" SOCKPATH_FILE "%u", uid, unit);
 	ca.sun_family = AF_UNIX;
 	s = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
 	if (s < 0)
@@ -392,7 +408,7 @@ aucat_connect_un(struct aucat *hdl, unsigned int unit)
 		DPERROR(ca.sun_path);
 		/* try shared server */
 		snprintf(ca.sun_path, sizeof(ca.sun_path),
-		    "/tmp/aucat/%s%u", AUCAT_PATH, unit);
+		    SOCKPATH_DIR "/" SOCKPATH_FILE "%u", unit);
 		while (connect(s, (struct sockaddr *)&ca, len) < 0) {
 			if (errno == EINTR)
 				continue;
diff --git a/libsndio/debug.c b/libsndio/debug.c
index c02508c..eebf2bc 100644
--- a/libsndio/debug.c
+++ b/libsndio/debug.c
@@ -54,3 +54,27 @@ _sndio_parsetype(const char *str, char *type)
 		return NULL;
 	return str;
 }
+
+const char *
+_sndio_parsenum(const char *str, unsigned int *num, unsigned int max)
+{
+	const char *p = str;
+	unsigned int dig, maxq, maxr, val;
+
+	val = 0;
+	maxq = max / 10;
+	maxr = max % 10;
+	for (;;) {
+		dig = *p - '0';
+		if (dig >= 10)
+			break;
+		if (val > maxq || (val == maxq && dig > maxr))
+			return NULL;
+		val = val * 10 + dig;
+		p++;
+	}
+	if (p == str)
+		return NULL;
+	*num = val;
+	return p;
+}
diff --git a/libsndio/debug.h b/libsndio/debug.h
index 7594784..2433ace 100644
--- a/libsndio/debug.h
+++ b/libsndio/debug.h
@@ -22,7 +22,7 @@
 
 #define DPRINTFN(n, ...)					\
 	do {							\
-		if (_sndio_debug >= (n))				\
+		if (_sndio_debug >= (n))			\
 			fprintf(stderr, __VA_ARGS__);		\
 	} while(0)
 
@@ -47,5 +47,6 @@ extern int _sndio_debug;
 #endif
 
 const char *_sndio_parsetype(const char *, char *);
+const char *_sndio_parsenum(const char *, unsigned int *, unsigned int);
 
 #endif
diff --git a/libsndio/mio_alsa.c b/libsndio/mio_alsa.c
index b88ba9a..fa74d4a 100644
--- a/libsndio/mio_alsa.c
+++ b/libsndio/mio_alsa.c
@@ -31,6 +31,8 @@
 #include "debug.h"
 #include "mio_priv.h"
 
+#define DEVNAME_PREFIX "hw:"
+
 #ifdef DEBUG
 static snd_output_t *output = NULL;
 #define DALSA(str, err) fprintf(stderr, "%s: %s\n", str, snd_strerror(err)) 
@@ -40,6 +42,7 @@ static snd_output_t *output = NULL;
 
 struct mio_alsa_hdl {
 	struct mio_hdl mio;
+	char *devname;
 	snd_rawmidi_t *in, *out;
 	int infds, onfds, nfds, events;
 };
@@ -64,7 +67,7 @@ struct mio_hdl *
 mio_alsa_open(const char *str, unsigned int mode, int nbio)
 {
 	struct mio_alsa_hdl *hdl;
-	char path[PATH_MAX];
+	size_t len;
 	int rc;
 
 	switch (*str) {
@@ -84,11 +87,20 @@ mio_alsa_open(const char *str, unsigned int mode, int nbio)
 	if (rc < 0)
 		DALSA("couldn't attach to stderr", rc);
 #endif
-	snprintf(path, sizeof(path), "hw:%s", str);
+	len = strlen(str);
+	hdl->devname = malloc(len + sizeof(DEVNAME_PREFIX));
+	if (hdl->devname == NULL) {
+		free(hdl);
+		return NULL;
+	}
+	memcpy(hdl->devname, DEVNAME_PREFIX, sizeof(DEVNAME_PREFIX) - 1);
+	memcpy(hdl->devname + sizeof(DEVNAME_PREFIX) - 1, str, len + 1);
 	hdl->in = hdl->out = NULL;
-	rc = snd_rawmidi_open(&hdl->in, &hdl->out, path, SND_RAWMIDI_NONBLOCK);
+	rc = snd_rawmidi_open(&hdl->in, &hdl->out,
+	    hdl->devname, SND_RAWMIDI_NONBLOCK);
 	if (rc) {
 		DALSA("could't open port", rc);
+		free(hdl->devname);
 		free(hdl);
 		return NULL;
 	}
@@ -111,6 +123,7 @@ mio_alsa_close(struct mio_hdl *sh)
 		snd_rawmidi_drain(hdl->out);
 		snd_rawmidi_close(hdl->out);
 	}
+	free(hdl->devname);
 	free(hdl);
 }
 
diff --git a/libsndio/mio_rmidi.c b/libsndio/mio_rmidi.c
index 7020f73..6d88976 100644
--- a/libsndio/mio_rmidi.c
+++ b/libsndio/mio_rmidi.c
@@ -30,6 +30,11 @@
 #include "debug.h"
 #include "mio_priv.h"
 
+#define DEVPATH_PREFIX	"/dev/rmidi"
+#define DEVPATH_MAX 	(1 +		\
+	sizeof(DEVPATH_PREFIX) - 1 +	\
+	sizeof(int) * 3)
+
 struct mio_rmidi_hdl {
 	struct mio_hdl mio;
 	int fd;
@@ -56,22 +61,27 @@ _mio_rmidi_open(const char *str, unsigned int mode, int nbio)
 {
 	int fd, flags;
 	struct mio_rmidi_hdl *hdl;
-	char path[PATH_MAX];
+	char path[DEVPATH_MAX];
+	unsigned int devnum;
 
 	switch (*str) {
 	case '/':
 		str++;
 		break;
 	default:
-		DPRINTF("_sio_sun_open: %s: '/<devnum>' expected\n", str);
+		DPRINTF("_mio_rmidi_open: %s: '/<devnum>' expected\n", str);
+		return NULL;
+	}
+	str = _sndio_parsenum(str, &devnum, 255);
+	if (str == NULL || *str != '\0') {
+		DPRINTF("_mio_rmidi_open: can't determine device number\n");
 		return NULL;
 	}
 	hdl = malloc(sizeof(struct mio_rmidi_hdl));
 	if (hdl == NULL)
 		return NULL;
 	_mio_create(&hdl->mio, &mio_rmidi_ops, mode, nbio);
-
-	snprintf(path, sizeof(path), "/dev/rmidi%s", str);
+	snprintf(path, sizeof(path), DEVPATH_PREFIX "%u", devnum);
 	if (mode == (MIO_OUT | MIO_IN))
 		flags = O_RDWR;
 	else
diff --git a/libsndio/sio_alsa.c b/libsndio/sio_alsa.c
index 29e1696..66b858f 100644
--- a/libsndio/sio_alsa.c
+++ b/libsndio/sio_alsa.c
@@ -35,6 +35,8 @@
 #include "sio_priv.h"
 #include "bsd-compat.h"
 
+#define DEVNAME_PREFIX "hw:"
+
 #ifdef DEBUG
 static snd_output_t *output = NULL;
 #define DALSA(str, err) fprintf(stderr, "%s: %s\n", str, snd_strerror(err)) 
@@ -45,6 +47,7 @@ static snd_output_t *output = NULL;
 struct sio_alsa_hdl {
 	struct sio_hdl sio;
 	struct sio_par par;
+	char *devname;
 	snd_pcm_t *opcm;
 	snd_pcm_t *ipcm;
 	unsigned ibpf, obpf;		/* bytes per frame */
@@ -273,8 +276,8 @@ struct sio_hdl *
 _sio_alsa_open(const char *str, unsigned mode, int nbio)
 {
 	struct sio_alsa_hdl *hdl;
-	char path[PATH_MAX];
 	struct sio_par par;
+	size_t len;
 	int err;
 
 	switch (*str) {
@@ -282,7 +285,7 @@ _sio_alsa_open(const char *str, unsigned mode, int nbio)
 		str++;
 		break;
 	default:
-		DPRINTF("_sio_sun_open: %s: '/<devnum>' expected\n", str);
+		DPRINTF("_sio_alsa_open: %s: '/<devnum>' expected\n", str);
 		return NULL;
 	}
 	hdl = malloc(sizeof(struct sio_alsa_hdl));
@@ -295,10 +298,14 @@ _sio_alsa_open(const char *str, unsigned mode, int nbio)
 	if (err < 0)
 		DALSA("couldn't attach to stderr", err);
 #endif
-
-	snprintf(path, sizeof(path), "hw:%s", str);
+	len = strlen(str);
+	hdl->devname = malloc(len + sizeof(DEVNAME_PREFIX));
+	if (hdl->devname == NULL)
+		goto bad_free_hdl;
+	memcpy(hdl->devname, DEVNAME_PREFIX, sizeof(DEVNAME_PREFIX) - 1);
+	memcpy(hdl->devname + sizeof(DEVNAME_PREFIX) - 1, str, len + 1);
 	if (mode & SIO_PLAY) {
-		err = snd_pcm_open(&hdl->opcm, path,
+		err = snd_pcm_open(&hdl->opcm, hdl->devname,
 		    SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
 		if (err < 0) {
 			DALSA("couldn't open play stream", err);
@@ -306,7 +313,7 @@ _sio_alsa_open(const char *str, unsigned mode, int nbio)
 		}
 	}
 	if (mode & SIO_REC) {
-		err = snd_pcm_open(&hdl->ipcm, path,
+		err = snd_pcm_open(&hdl->ipcm, hdl->devname,
 		    SND_PCM_STREAM_CAPTURE, SND_PCM_NONBLOCK);
 		if (err < 0) {
 			DALSA("couldn't open rec stream", err);
@@ -345,6 +352,8 @@ bad_free_opcm:
 	if (mode & SIO_PLAY)
 		snd_pcm_close(hdl->opcm);
 bad_free:
+	free(hdl->devname);
+bad_free_hdl:
 	free(hdl);
 	return NULL;
 }
@@ -358,6 +367,7 @@ sio_alsa_close(struct sio_hdl *sh)
 		snd_pcm_close(hdl->opcm);
 	if (hdl->sio.mode & SIO_REC)
 		snd_pcm_close(hdl->ipcm);
+	free(hdl->devname);
 	free(hdl);
 }
 
diff --git a/libsndio/sio_sun.c b/libsndio/sio_sun.c
index db44f3c..db32661 100644
--- a/libsndio/sio_sun.c
+++ b/libsndio/sio_sun.c
@@ -34,6 +34,11 @@
 #include "sio_priv.h"
 #include "bsd-compat.h"
 
+#define DEVPATH_PREFIX	"/dev/audio"
+#define DEVPATH_MAX 	(1 +		\
+	sizeof(DEVPATH_PREFIX) - 1 +	\
+	sizeof(int) * 3)
+
 struct sio_sun_hdl {
 	struct sio_hdl sio;
 	int fd;
@@ -332,7 +337,8 @@ _sio_sun_open(const char *str, unsigned int mode, int nbio)
 	struct audio_info aui;
 	struct sio_sun_hdl *hdl;
 	struct sio_par par;
-	char path[PATH_MAX];
+	char path[DEVPATH_MAX];
+	unsigned int devnum;
 
 	switch (*str) {
 	case '/':
@@ -342,12 +348,17 @@ _sio_sun_open(const char *str, unsigned int mode, int nbio)
 		DPRINTF("_sio_sun_open: %s: '/<devnum>' expected\n", str);
 		return NULL;
 	}
+	str = _sndio_parsenum(str, &devnum, 255);
+	if (str == NULL || *str != '\0') {
+		DPRINTF("_sio_sun_open: can't determine device number\n");
+		return NULL;
+	}
 	hdl = malloc(sizeof(struct sio_sun_hdl));
 	if (hdl == NULL)
 		return NULL;
 	_sio_create(&hdl->sio, &sio_sun_ops, mode, nbio);
 
-	snprintf(path, sizeof(path), "/dev/audio%s", str);
+	snprintf(path, sizeof(path), DEVPATH_PREFIX "%u", devnum);
 	if (mode == (SIO_PLAY | SIO_REC))
 		flags = O_RDWR;
 	else