Get the signal thread (and thus Apache threaded MPMs) working properly

on AIX and Tru64.

On certain platforms, sigwait() returns EINVAL if any of various
unblockable signals are included in the mask.  This was first observed
on AIX and Tru64.

On AIX (4.3.3, at least), sigwait() won't wake up if the high-order bit
of the second word of flags is turned on.  sigdelset() returns an error
when trying to turn this off, so we'll turn it off manually.


git-svn-id: https://svn.apache.org/repos/asf/apr/apr/trunk@61326 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 27 insertions, 0 deletions

diff --git a/threadproc/unix/signals.c b/threadproc/unix/signals.c
index 2c27f4ace..df69f7cc5 100644
--- a/threadproc/unix/signals.c
+++ b/threadproc/unix/signals.c
@@ -275,6 +275,33 @@ static void *signal_thread_func(void *signal_handler)
 
     /* This thread will be the one responsible for handling signals */
     sigfillset(&sig_mask);
+
+    /* On certain platforms, sigwait() returns EINVAL if any of various
+     * unblockable signals are included in the mask.  This was first 
+     * observed on AIX and Tru64.
+     */
+#ifdef SIGKILL
+    sigdelset(&sig_mask, SIGKILL);
+#endif
+#ifdef SIGSTOP
+    sigdelset(&sig_mask, SIGSTOP);
+#endif
+#ifdef SIGCONT
+    sigdelset(&sig_mask, SIGCONT);
+#endif
+#ifdef SIGWAITING
+    sigdelset(&sig_mask, SIGWAITING);
+#endif
+
+    /* On AIX (4.3.3, at least), sigwait() won't wake up if the high-
+     * order bit of the second word of flags is turned on.  sigdelset()
+     * returns an error when trying to turn this off, so we'll turn it
+     * off manually.
+     */
+#ifdef _AIX
+    sig_mask.hisigs &= 0x7FFFFFFF;
+#endif
+
     while (1) {
         int signal_received;