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AudioAlsa/AudioOss: set FD_CLOEXEC flag for file descriptors

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Per default child processes inherit all file descriptors of their
parent process. This applied for file descriptors pointing to sound
devices as well. Reopening sound devices while e.g. a ZynAddSubFX
process was running always failed due to this "feature".

By manually setting the FD_CLOEXEC flag for the sound device file
descriptors they do not get inherited by child processes anymore.
This commit is contained in:
Tobias Doerffel
2009-08-18 15:27:43 +02:00
parent c8d5497486
commit 80f101cec6
2 changed files with 19 additions and 0 deletions
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15
src/core/audio/AudioAlsa.cpp
View File

@@ -79,6 +79,21 @@ AudioAlsa::AudioAlsa( bool & _success_ful, mixer * _mixer ) :
return;
}
// set FD_CLOEXEC flag for all file descriptors so forked processes
// do not inherit them
struct pollfd * ufds;
int count = snd_pcm_poll_descriptors_count( m_handle );
ufds = new pollfd[count];
snd_pcm_poll_descriptors( m_handle, ufds, count );
for( int i = 0; i < qMax( 3, count ); ++i )
{
const int fd = ( i >= count ) ? ufds[0].fd+i : ufds[i].fd;
int oldflags = fcntl( fd, F_GETFD, 0 );
if( oldflags < 0 )
continue;
oldflags |= FD_CLOEXEC;
fcntl( fd, F_SETFD, oldflags );
}
_success_ful = true;
}

4
src/core/audio/AudioOss.cpp
View File

@@ -98,6 +98,10 @@ AudioOss::AudioOss( bool & _success_ful, mixer * _mixer ) :
return;
}
// set FD_CLOEXEC flag for file descriptor so forked processes
// do not inherit it
fcntl( m_audioFD, F_SETFD, fcntl( m_audioFD, F_GETFD ) | FD_CLOEXEC );
int frag_spec;
for( frag_spec = 0; static_cast<int>( 0x01 << frag_spec ) <
getMixer()->framesPerPeriod() * channels() *