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added workaround to avoid hangs in child processes (by starting of postprocess or nzbprocess), observed on uClibC based systems

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This commit is contained in:
Andrey Prygunkov
2008-11-13 16:50:02 +00:00
parent 0971ba5cee
commit b823535880
1 changed files with 92 additions and 3 deletions
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95
ScriptController.cpp
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@@ -54,6 +54,51 @@ extern Options* g_pOptions;
static const int POSTPROCESS_PARCHECK_CURRENT = 91;
static const int POSTPROCESS_PARCHECK_ALL = 92;
#ifndef WIN32
#define CHILD_WATCHDOG 1
#endif
#ifdef CHILD_WATCHDOG
/**
* Sometimes the forked child process doesn't start properly and hangs
* just during the starting. I didn't find any explanation about what
* could cause that problem except of a general advice, that
* "a forking in a multithread application is not recommended".
*
* Workaround:
* 1) child process prints a line into stdout directly after the start;
* 2) parent process waits for a line for 60 seconds. If it didn't receive it
* the cild process assumed to hang and will be killed. Another attempt
* will be made.
*/
class ChildWatchDog : public Thread
{
private:
pid_t m_hProcessID;
protected:
virtual void Run();
public:
void SetProcessID(pid_t hProcessID) { m_hProcessID = hProcessID; }
};
void ChildWatchDog::Run()
{
static const int WAIT_SECONDS = 60;
time_t tStart = time(NULL);
while (!IsStopped() && (time(NULL) - tStart) < WAIT_SECONDS)
{
usleep(10 * 1000);
}
if (!IsStopped())
{
info("Restarting hanging child process");
kill(m_hProcessID, SIGKILL);
}
}
#endif
ScriptController::ScriptController()
{
m_szScript = NULL;
@@ -72,8 +117,15 @@ int ScriptController::Execute()
return -1;
}
int iExitCode = 0;
int pipein;
#ifdef CHILD_WATCHDOG
bool bChildConfirmed = false;
while (!bChildConfirmed && !m_bTerminated)
{
#endif
#ifdef WIN32
// build command line
char szCmdLine[2048];
@@ -168,6 +220,10 @@ int ScriptController::Execute()
close(pipeout);
#ifdef CHILD_WATCHDOG
fwrite("\n", 1, 2, stdout);
#endif
execvp(m_szScript, (char* const*)m_szArgs);
fprintf(stdout, "[ERROR] Could not start script: %s", strerror(errno));
fflush(stdout);
@@ -192,6 +248,14 @@ int ScriptController::Execute()
return -1;
}
#ifdef CHILD_WATCHDOG
debug("Creating child watchdog");
ChildWatchDog* pWatchDog = new ChildWatchDog();
pWatchDog->SetAutoDestroy(false);
pWatchDog->SetProcessID(pid);
pWatchDog->Start();
#endif
char* buf = (char*)malloc(10240);
debug("Entering pipe-loop");
@@ -199,10 +263,31 @@ int ScriptController::Execute()
{
if (fgets(buf, 10240, readpipe))
{
#ifdef CHILD_WATCHDOG
if (!bChildConfirmed)
{
bChildConfirmed = true;
pWatchDog->Stop();
debug("Child confirmed");
}
#endif
ProcessOutput(buf);
}
}
debug("Exited pipe-loop");
#ifdef CHILD_WATCHDOG
debug("Destroying WatchDog");
if (!bChildConfirmed)
{
pWatchDog->Stop();
}
while (pWatchDog->IsRunning())
{
usleep(1 * 1000);
}
delete pWatchDog;
#endif
free(buf);
fclose(readpipe);
@@ -212,7 +297,7 @@ int ScriptController::Execute()
warn("Interrupted %s", m_szInfoName);
}
int iExitCode = 0;
iExitCode = 0;
#ifdef WIN32
WaitForSingleObject(m_hProcess, INFINITE);
@@ -227,7 +312,11 @@ int ScriptController::Execute()
iExitCode = WEXITSTATUS(iStatus);
}
#endif
#ifdef CHILD_WATCHDOG
} // while (!bChildConfirmed && !m_bTerminated)
#endif
if (!m_bTerminated)
{
info("Completed %s", m_szInfoName);
@@ -245,7 +334,7 @@ void ScriptController::Terminate()
#ifdef WIN32
BOOL bOK = TerminateProcess(m_hProcess, -1);
#else
bool bOK = kill(m_hProcess, 9) == 0;
bool bOK = kill(m_hProcess, SIGKILL) == 0;
#endif
if (bOK)