X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/6e9ddbb313cf7db66550f93a74cbba12e39e93c0..81deba3d7a2b187d58fe26bd8b4eafb5687095e1:/lib/pthread_sigmask.c

diff --git a/lib/pthread_sigmask.c b/lib/pthread_sigmask.c
index 11d549cad4..982ae6003c 100644
--- a/lib/pthread_sigmask.c
+++ b/lib/pthread_sigmask.c
@@ -1,5 +1,5 @@
 /* POSIX compatible signal blocking for threads.
-   Copyright (C) 2011 Free Software Foundation, Inc.
+   Copyright (C) 2011-2015 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -22,6 +22,10 @@
 #include <errno.h>
 #include <stddef.h>
 
+#if PTHREAD_SIGMASK_INEFFECTIVE
+# include <string.h>
+#endif
+
 #if PTHREAD_SIGMASK_UNBLOCK_BUG
 # include <unistd.h>
 #endif
@@ -31,7 +35,22 @@ pthread_sigmask (int how, const sigset_t *new_mask, sigset_t *old_mask)
 #undef pthread_sigmask
 {
 #if HAVE_PTHREAD_SIGMASK
-  int ret = pthread_sigmask (how, new_mask, old_mask);
+  int ret;
+
+# if PTHREAD_SIGMASK_INEFFECTIVE
+  sigset_t omask, omask_copy;
+  sigset_t *old_mask_ptr = &omask;
+  sigemptyset (&omask);
+  /* Add a signal unlikely to be blocked, so that OMASK_COPY
+     is unlikely to match the actual mask.  */
+  sigaddset (&omask, SIGILL);
+  memcpy (&omask_copy, &omask, sizeof omask);
+# else
+  sigset_t *old_mask_ptr = old_mask;
+# endif
+
+  ret = pthread_sigmask (how, new_mask, old_mask_ptr);
+
 # if PTHREAD_SIGMASK_INEFFECTIVE
   if (ret == 0)
     {
@@ -39,12 +58,16 @@ pthread_sigmask (int how, const sigset_t *new_mask, sigset_t *old_mask)
          Don't cache the information: libpthread.so could be dynamically
          loaded after the program started and after pthread_sigmask was
          called for the first time.  */
-      if (pthread_sigmask (1729, NULL, NULL) == 0)
+      if (memcmp (&omask_copy, &omask, sizeof omask) == 0
+          && pthread_sigmask (1729, &omask_copy, NULL) == 0)
         {
           /* pthread_sigmask is currently ineffective.  The program is not
              linked to -lpthread.  So use sigprocmask instead.  */
           return (sigprocmask (how, new_mask, old_mask) < 0 ? errno : 0);
         }
+
+      if (old_mask)
+        memcpy (old_mask, &omask, sizeof omask);
     }
 # endif
 # if PTHREAD_SIGMASK_FAILS_WITH_ERRNO