/sys/kernel/debug/tracing/... files are accessible on android.

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Bartosz Taudul 2021-12-21 21:10:17 +01:00
parent efae847690
commit f1fa352a13
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@ -766,70 +766,6 @@ static const char* ReadFile( const char* path )
return tmp;
}
#ifdef __ANDROID__
static const char* ReadFileElevated( const char* path )
{
// Explanation for "su root sh -c": there are 2 flavors of "su" in circulation
// on Android. The default Android su has the following syntax to run a command
// as root:
// su root 'command'
// and 'command' is exec'd not passed to a shell, so if shell interpretation is
// wanted, one needs to do:
// su root sh -c 'command'
// Besides that default Android 'su' command, some Android devices use a different
// su with a command-line interface closer to the familiar util-linux su found
// on Linux distributions. Fortunately, both the util-linux su and the one
// in https://github.com/topjohnwu/Magisk seem to be happy with the above
// `su root sh -c 'command'` command line syntax.
int pipefd[2];
if( pipe( pipefd ) == 0 )
{
const auto pid = fork();
if( pid == 0 )
{
// child
close( pipefd[0] );
dup2( open( "/dev/null", O_WRONLY ), STDERR_FILENO );
if( dup2( pipefd[1], STDOUT_FILENO ) >= 0 )
{
close( pipefd[1] );
char tmp[1024];
sprintf( tmp, "cat %s", path );
execlp( "su", "su", "root", "sh", "-c", tmp, (char*)nullptr );
exit( 1 );
}
exit( 0 );
}
else if( pid > 0 )
{
// parent
close( pipefd[1] );
static char tmp[64];
const auto sz = read( pipefd[0], tmp, 63 );
close( pipefd[0] );
waitpid( pid, nullptr, 0 );
if( sz <= 0 ) return nullptr;
tmp[sz] = '\0';
return tmp;
}
else
{
return nullptr;
}
}
else
{
return nullptr;
}
}
#else
static const char* ReadFileElevated( const char* path )
{
return ReadFile( path );
}
#endif
bool SysTraceStart( int64_t& samplingPeriod )
{
#ifndef CLOCK_MONOTONIC_RAW
@ -843,9 +779,9 @@ bool SysTraceStart( int64_t& samplingPeriod )
TracyDebug( "perf_event_paranoid: %i\n", paranoidLevel );
int switchId = -1, wakeupId = -1;
const auto switchIdStr = ReadFileElevated( "/sys/kernel/debug/tracing/events/sched/sched_switch/id" );
const auto switchIdStr = ReadFile( "/sys/kernel/debug/tracing/events/sched/sched_switch/id" );
if( switchIdStr ) switchId = atoi( switchIdStr );
const auto wakeupIdStr = ReadFileElevated( "/sys/kernel/debug/tracing/events/sched/sched_wakeup/id" );
const auto wakeupIdStr = ReadFile( "/sys/kernel/debug/tracing/events/sched/sched_wakeup/id" );
if( wakeupIdStr ) wakeupId = atoi( wakeupIdStr );
TracyDebug( "sched_switch id: %i\nsched_wakeup id: %i\n", switchId, wakeupId );