Bugs item #3559382, was opened at 2012-08-19 03:03
Message generated for change (Comment added) made by boxofrox
You can respond by visiting:
https://sourceforge.net/tracker/?func=detail&atid=110706&aid=3559382&group_id=10706
Please note that this message will contain a full copy of the comment thread,
including the initial issue submission, for this request,
not just the latest update.
Category: None
Group: None
Status: Open
Resolution: None
>Priority: 1
Private: No
Submitted By: boxofrox (boxofrox)
Assigned to: Nobody/Anonymous (nobody)
Summary: sox does not respond to SIGINT on Mac OSX over ssh
Initial Comment:
Summary:
When running sox as a background job on a Mac OS system via a SSH connection,
I try to stop sox with 'kill -SIGINT <pid>', and nothing happens. I expect sox
to quit gracefully, instead it continues running/sleeping.
-----------------------------------------------------
Background:
The goal is to pipe audio from my landlord's Mac microphone through SSH to my
Linux speakers. We're trying to set up a means for me to hear his ADT alarm
while he's out of town when someone breaks in.
I initiate the SSH connection from my Linux computer and pipe a remote sox
command back to my system where I use sox to play the piped audio. It works
great.
The problem is, at first, using Ctrl-C locally killed my sox process, but left
sox running on the Mac. So I decided to expand the remote bash command to read
input from my Linux terminal until an EOF character was sent, then interrupt
the remote sox process, but the remote sox process keeps running.
-----------------------------------------------------
System Details:
Mac OS X 11.4.0 x86_64
sox v14.4.0
Linux Gentoo Kernel 3.2.12 x86
sox v14.3.2
-----------------------------------------------------
Test Case to Reproduce:
1. Get a Mac. This will be the remote system.
2. Get another *nix system. This will be the local system.
3. Turn on Remote Access in System Properties -> Network -> Shares for the
remote Mac.
4. On the local *nix, open two terminals
5. In the first terminal, run
local # ssh -p 22 <username>@<remote ip>
remote # { sox -q -t coreaudio "default" -p & echo -e "\npid = $! \n" 1>&2;
} | sox -p - > /dev/null
a. record the pid
6. In the second terminal, run
local # ssh -p 22 <username>@<remote ip>
remote # kill -SIGINT <pid>
remote # ps -l <pid>
7. Observe that sox is still running/sleeping and did not quit.
8. In the second terminal, run
remote # kill -SIGKILL <pid>
9. Observe the output in the first terminal.
pid = 54290
sox FAIL formats: can't open input `-': premature EOF
10. Notice that sox did not quit gracefully.
-----------------------------------------------------
Expected Behavior:
1. On a Linux system, open two terminals.
2. In the first terminal, run
# { sox -q -t alsa hw:1,0 -p & echo -e "\npid = $!\n" 1>&2; } | sox -p - >
/dev/null
a. record the pid
3. In the second terminal, run
# kill -SIGINT <pid>
4. Observe the output in the first terminal.
pid = 20376
-: (sox)
Encoding: Signed PCM
Channels: 1 @ 32-bit
Samplerate: 48000Hz
Replaygain: off
Duration: unknown
In:0.00% 00:04:36.82 [00:00:00.00] Out:13.3M [ | ] Clip:0
Aborted.
In:0.00% 00:04:36.65 [00:00:00.00] Out:13.3M [ | ] Clip:0
Done.
5. Notice that sox quit gracefully at both ends of the pipe.
-----------------------------------------------------
SSH Scripts:
These are the ssh scripts I described in the Background section. It's FYI.
#!/bin/bash
# version 0.1
# warning: this script does not terminate the remote sox process.
REMOTE_USER=
REMOTE_HOST=
echo ":: Press Ctrl-C to stop."
ssh $REMOTE_USER@$REMOTE_HOST -p 22 'sox -q -t coreaudio "default" -p' | sox -p
-t alsa
#!/bin/bash
# version 0.2
# warning: this script does not terminate the remote sox process. switch to
kill -KILL instead, but the local sox process will complain.
REMOTE_USER=
REMOTE_HOST=
echo ":: Press Ctrl-D to stop."
ssh $REMOTE_USER@$REMOTE_HOST -p 22 'sox -q -t coreaudio "default" -p & pid=$!
; while read >/dev/null ; do echo > /dev/null; done ; kill -INT $pid; echo -e
"\nkill -INT $pid\n" 1>&2;' | sox -p -t alsa
-----------------------------------------------------
Epilogue:
I don't know if this is an issue with Mac OSX, it's Bash shell, it's kill
utility, or with sox. Since I'm piping the audio directly to my speaker, the
EOF complaint from sox does not hurt anyting. This issue may matter when
piping the audio into a formatted audio file (like .mp3).
If this issue cannot be resolved in sox, then this report will serve to
document this behavior.
----------------------------------------------------------------------
>Comment By: boxofrox (boxofrox)
Date: 2012-08-19 14:02
Message:
This may be an issue with a blocking call.
After the first success with hearing audio from his microphone, further
attempts--when I was adding Ctrl-D feature--failed. The first hanging sox
process was killed with 'kill -KILL', so it's probable that the microphone
was not released properly. During the failed attempts to hear audio, a 'ps
-l | grep sox' showed that sox was sleeping, not running.
My landlord reset his Mac today. The audio feed is working again, and the
'kill -SIGINT <sox pid>' worked.
So maybe sox was ignoring the SIGINT earlier, because it was blocked by a
system call. I'm not sure if this is correct or even plausible, so I'll
leave it to one more experienced than myself to decide.
----------------------------------------------------------------------
You can respond by visiting:
https://sourceforge.net/tracker/?func=detail&atid=110706&aid=3559382&group_id=10706
------------------------------------------------------------------------------
Live Security Virtual Conference
Exclusive live event will cover all the ways today's security and
threat landscape has changed and how IT managers can respond. Discussions
will include endpoint security, mobile security and the latest in malware
threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
_______________________________________________
SoX-devel mailing list
SoX-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/sox-devel
