Hi,
if the exec in cygrunsrv fails or the command exits to early, cygrunsrv
will hang forever.
The service can no longer be controlled until cygrunsrv has been kill(-9)ed.
Auto restart of service does not work in this case.
Steps to reproduce (at least on XP SP2):
$ cygrunsrv -I test -p /bin/true
$ cygrunsrv -S test
cygrunsrv: Error starting a service: ... Win32 error 1053:
...
$ sleep 3600 #;-)
$ cygrunsrv -S test
Service : test
Current State : Start Pending
Controls Accepted : Stop
Command : /bin/true
cygrunsrv process has to be killed manually.
Same result occurs if the command's exe is removed.
This is due to the following (IMO undocumented and "interesting";-)
behavior of the windows SCM:
The StartServiceControlDispatcher() routine does not return unless some
thread (no necessarily service_main()) sets SERVICE_STOPPED.
The service_main() thread started by SCM is left alone.
Exiting service_main() does nothing, in particular it does not end
StartServiceControlDispatcher().
But, if SERVICE_STOPPED is set, StartServiceControlDispatcher()
immediately returns, again without any care about service_main().
Because usually now the program exit()'s and kills all threads, code
following SERVICE_STOPPED may not be executed at all.
The attached patch for cygrunsrv-1.10.1 demonstrates this behavior via
LOG_DEBUG messages.
With the _exit() at the end of service_main(), cygrunsrv does no longer
hang and auto-restart of services works.
Note that the messages at the end of service_main() will never be
written if a service exits normally
(Try with: cygrunsrv -I ... -p /bin/sleep -a 30)
Thanks for any comment
Christian
--- cygrunsrv.cc.orig 2005-05-22 18:34:55.001000000 +0200
+++ cygrunsrv.cc 2005-11-12 17:33:50.546875000 +0100
@@ -1591,6 +1591,10 @@
svcname, WTERMSIG (status));
break;
}
+ syslog(LOG_DEBUG,"service_main(): sleep(10)");
+ sleep(10);
+ syslog(LOG_DEBUG,"service_main(): _exit(%d)", service_main_exitval);
+ _exit(service_main_exitval);
}
int
@@ -1635,6 +1639,7 @@
ste[1].lpServiceProc = NULL;
if (!StartServiceCtrlDispatcherA(ste))
return error (StartAsSvcErr);
+ syslog(LOG_DEBUG,"main(): exit(%d)", service_main_exitval);
return service_main_exitval;
}
/* Started with parameters: Install, deinstall, start or stop a service. */
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