Alexandre Ratchov wrote:
Initially aucat was designed to handle one device only so multiple
audio devices used to be supported simply by starting multiple aucat
processes (one per device), very simple. Then (~1.5 years ago) we
added support for multiple audio devices (ie multiple -f options), and
now it's time to finish the job and add a device number component in
sndio(7) device names. Since this partially breaks compatibility, this
is a opportunitiy to fix few other design mistakes (eg ':' being used
by inet6, type name vs api name confusion, etc..). This leads to the
following names:
type[@hostname][,unit]/devnum[.option]
Hi Alexandre,
The highlighted code at the bottom of this mail contains comparisons like
this: strncmp(snd, str, len) == 0
This makes it possible to do things like:
$ aucat -fsnds/0 -i${HOME}/them.wav
snd0: snds/0: failed to open audio device = Ok, this should fail
$ aucat -fsn/0 -i${HOME}/them.wav = Not Ok ???, this plays the music
The second call doesn't fail because if len is smaller then strlen(snd)
than it potentially matches a partial snd, allowing device types like s
and sn (in the case of type snd). I suppose this is not what you
intended.
I tend to do comparisons like this as follows,
strncmp(str, snd, sizeof(snd)) == 0,
using the NUL character in snd as a sort of boundary check.
I'm not 100% sure though that this is always safe when strlen(str)
sizeof(snd).
Maybe the safest option is to check if len == strlen(snd) before making
the comparison. This mail includes a PoC patch using this method.
After applying the patch aucat should behave like this:
$ aucat -fsnds/0 -i${HOME}/them.wav
snd0: snds/0: failed to open audio device
$ aucat -fsnd/0 -i${HOME}/them.wav = Ok, playing music
$ aucat -fsn/0 -i${HOME}/them.wav
snd0: sn/0: failed to open audio device
$ aucat -fs/0 -i${HOME}/them.wav
snd0: s/0: failed to open audio device
$ aucat -f/0 -i${HOME}/them.wav
snd0: /0: failed to open audio device
$ aucat -f0 -i${HOME}/them.wav
snd0: 0: failed to open audio device
Though I patched mio.c I didn't actually test midicat.
For this proof-of-concept I only tested aucat with device types snd and
rsnd, which seem to work for me.
Some other more or less random weirdness I found is that I can specify either
sun, sun: or sun:0 for the device and all three of them will play sound.
I'd expect only sun:0 to work. Device aucat hasn't got this problem. I haven't
tracked this down but I suspect some additional checking is going on outside
the sio_open function.
P.S.:
I added a comparison function sio_is_type. But I didn't know how to share it
properly between sio.c and mio.c so my solution might look a bit quick and
dirty. (especially the extern sio_is_type declaration in mio.c)
Index: lib/libsndio/mio.c
===
RCS file: /cvs/src/lib/libsndio/mio.c,v
retrieving revision 1.12
diff -u -p -r1.12 mio.c
--- lib/libsndio/mio.c17 Oct 2011 21:09:11 - 1.12
+++ lib/libsndio/mio.c8 Nov 2011 19:18:19 -
@@ -49,26 +46,23 @@ mio_open(const char *str, unsigned mode,
if (str == NULL !issetugid())
str = getenv(MIDIDEVICE);
if (str == NULL) {
- hdl = mio_aucat_open(0, mode, nbio);
+ hdl = mio_aucat_open(/0, mode, nbio, 1);
if (hdl != NULL)
return hdl;
- return mio_rmidi_open(0, mode, nbio);
+ return mio_rmidi_open(/0, mode, nbio);
}
- sep = strchr(str, ':');
- if (sep == NULL) {
- DPRINTF(mio_open: %s: ':' missing in device name\n, str);
- return NULL;
+ for (len = 0; (c = str[len]) != '\0'; len++) {
+ /* XXX: remove ':' compat bits */
+ if (c == ':' || c == '@' || c == '/' || c == ',')
+ break;
}
- len = sep - str;
- if (len == (sizeof(prefix_midithru) - 1)
- memcmp(str, prefix_midithru, len) == 0)
- return mio_aucat_open(sep + 1, mode, nbio);
- if (len == (sizeof(prefix_aucat) - 1)
- memcmp(str, prefix_aucat, len) == 0)
- return mio_aucat_open(sep + 1, mode, nbio);
- if (len == (sizeof(prefix_rmidi) - 1)
- memcmp(str, prefix_rmidi, len) == 0)
- return mio_rmidi_open(sep + 1, mode, nbio);
+ if (strncmp(snd, str, len) == 0 ||
+ strncmp(aucat, str, len) == 0)
+ return mio_aucat_open(str + len, mode, nbio, 0);
+ if (strncmp(midithru, str, len) == 0)
+ return mio_aucat_open(str + len, mode, nbio, 1);
+ if (strncmp(rmidi, str, len) == 0)
+ return mio_rmidi_open(str + len, mode, nbio);
DPRINTF(mio_open: %s: unknown device type\n, str);
return NULL;
}
Index: lib/libsndio/sio.c
===
RCS file: /cvs/src/lib/libsndio/sio.c,v
retrieving revision 1.6
diff -u -p -r1.6 sio.c
--- lib/libsndio/sio.c9 May 2011
