checkX problems

[Lothar Brendel]

Mike Ayers wrote:
>> From: cygwin-xfree-owner@cygwin.com [mailto:cygwin-xfree-
>> owner@cygwin.com] On Behalf Of Lothar Brendel
>
>> Could you please clarify an issue here? (Sorry, it seems, I wronged
>> to ``run'' in the previous posts.)
>>
>> In a Windows command prompt (being somewhere on C:) I put the line
>>         \cygwin\bin\run -p /usr/bin sleep -wait 5
>> into a file ``dosleep.bat''. Executing that BAT-script (w/o any
>> wrapper), it
>> *does* sleep. Typing that very line directly at the prompt lets
>> ``run'' return immediately, though. Can you confirm this behaviour?
>
> I can confirm that without testing (so I'm probably chomping foot
> here...).  The sleep is holding the console open after run quits.

Sorry, I don't quite get it. *Which* console must it hold open? There is 
only the one I'm typing in and calling the BAT-script doesn't open another 
one. Hence, in how far does the environment of the BAT-script differ from 
the one of the command prompt?


>> Another possibility would be an option ``-n'' to specify the number
>> of retries.
>
> GAH!  No, that's just lame.

All right, all right, you just convinced me. :-)


> Just spawn/fork a
> sleep-then-interrupt-daddy thread/process, set up a SIGINT handler
> that exits with an error, loop connection attempts until successful,
> check X, kill child, exit with success.  That enforces both types of
> timeout.

Charles Wilson already set up this kind of infrastructure, I just had to 
introduce one more communication variable, cf. the patch below (positively 
tested on my system).

Yep, there are really two different purposes for a setting a timeout [i) 
"Just check whether an X server is available, but don't struggle with that 
too long." and ii) "There *should* be an X server coming up, just be a 
little patient."], but now both can be achieved by choosing either a short 
or a long duration.

Ciao
            Lothar


--- checkX.c-0.3.0 2009-06-15 02:29:07.000000000 +0200
+++ checkX.c 2009-11-14 19:36:31.000000000 +0100
@@ -32,6 +32,7 @@
 #endif

 #include <stdio.h>
+#include <errno.h>

 #if HAVE_SYS_TYPES_H
 # include <sys/types.h>
@@ -102,7 +103,8 @@

 static pthread_mutex_t mtx_xopenOK;
 static pthread_cond_t  cv_xopenOK;
-static int xopenOK = XSERV_TIMEDOUT;
+static int xopenOK;
+static int xopenTrying;
 static const char* XLIBfmt = "cygX11-%d.dll";
 static const char* DefaultAppendPath = "/usr/X11R6/bin" SEP_CHAR 
"/usr/bin";

@@ -314,6 +316,9 @@
   timespec_t     delta;
   timespec_t     then;

+  xopenTrying = delay!=0.0; /* false actually means: try once */
+  xopenOK = XSERV_NOTFOUND; /* a pessimistic start out */
+
   computeTimespec(fabs(delay), &delta);
   debugMsg(1, "(%s) Using delay of %d secs, %ld nanosecs (%5.2f)", 
__func__,
            delta.tv_sec, delta.tv_nsec,
@@ -333,15 +338,14 @@
   if (delay != 0.0) {
     clock_gettime(CLOCK_REALTIME, &now);
     timerspec_add(&now, &delta, &then);
-    pthread_cond_timedwait (&cv_xopenOK, &mtx_xopenOK, &then);
-  }
-
-  pthread_mutex_unlock(&mtx_xopenOK);
-
-  if (delay != 0.0) {
-    pthread_detach(id);
+    if (pthread_cond_timedwait (&cv_xopenOK, &mtx_xopenOK, &then) == 
ETIMEDOUT) {
+      xopenOK = XSERV_TIMEDOUT; /* it's okay, we have the mutex */
+      xopenTrying = 0;  /* allow open_display() to give up */
+    }    /* else open_display() was successful */
+    pthread_detach(id);  /* leave open_display() on its own */
   } else {
-    pthread_join(id, (void*)&status);
+    pthread_mutex_unlock(&mtx_xopenOK); /* allow open_display() to set 
xopenOK */
+    pthread_join(id, (void*)&status); /* and wait for it */
   }

   pthread_mutex_destroy(&mtx_xopenOK);
@@ -357,19 +361,17 @@
 open_display(void* /* WorkerThreadData* */ v)
 {
   Display* dpy;
-  int rc = 0;
   WorkerThreadData* data = (WorkerThreadData*)v;

-  if( (dpy = (*(data->xopendis))(data->displayname)) == NULL ) {
-    rc = 1;
-  } else {
-    (*(data->xclosedis))(dpy);
-    rc = 0;
-  }
-  pthread_mutex_lock (&mtx_xopenOK);
-  xopenOK = rc;
-  pthread_cond_signal(&cv_xopenOK);
-  pthread_mutex_unlock (&mtx_xopenOK);
+  do
+    if((dpy = (*(data->xopendis))(data->displayname))) {
+      (*(data->xclosedis))(dpy);
+      pthread_mutex_lock (&mtx_xopenOK);
+      xopenOK = XSERV_FOUND;
+      pthread_cond_signal(&cv_xopenOK);
+      pthread_mutex_unlock (&mtx_xopenOK);
+    }
+  while (xopenTrying && xopenOK == XSERV_NOTFOUND);

   pthread_exit((void*)0);
 }



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