On 1/12/22 08:51, Vasily Ulyanov wrote: > Hi Michal, >> > > So I can drop --pid and --daemon args from swtpm cmd and add > > virCommandSetPidFile(cmd, pidfile); > virCommandDaemonize(cmd); > > Then in virPidFileReadPathIfAlive() I can add a lock check. Hm... Nice, that > seems like a good way to go. > > Correct. That's common pattern. However, be aware that using virCommandDaemonize() makes the subsequent virCommandRun() return almost instantly, even before the actual binary that was intended to run is executed (if scheduler aligns things "well"). Therefore, checking for the child process is a bit trickier. But the pidfile is written before virCommandRun() returns, which is good. Moreover, it's not possible to use virCommandSetErrorBuffer() nor virCommandSetOutputBuffer() with virCommandDaemonize(). However, we have examples of how to use the pattern you suggested in our code. For instance qemuProcessStartManagedPRDaemon() or qemuSlirpStart(). You can find more by grepping for virCommandDaemonize(). Let me know if you need any help. Michal
