Initial import of the CDE 2.1.30 sources from the Open Group.

cde/lib/tt/mini_isam/issignals.c

@@ -0,0 +1,76 @@
+/*%%  (c) Copyright 1993, 1994 Hewlett-Packard Company			 */
+/*%%  (c) Copyright 1993, 1994 International Business Machines Corp.	 */
+/*%%  (c) Copyright 1993, 1994 Sun Microsystems, Inc.			 */
+/*%%  (c) Copyright 1993, 1994 Novell, Inc. 				 */
+/*%%  $XConsortium: issignals.c /main/3 1995/10/23 11:44:41 rswiston $ 			 				 */
+#ifndef lint
+static char sccsid[] = "@(#)issignals.c 1.7 89/08/30 Copyr 1988 Sun Micro";
+#endif
+/*
+ * Copyright (c) 1988 by Sun Microsystems, Inc.
+ */
+
+/*
+ * issignals.c
+ *
+ * Description:
+ *	Signal masking functions
+ */
+
+
+#include "isam_impl.h"
+#include <signal.h>
+
+/*
+ * _issignal_mask() is called at the beginning of each ISAM update operation
+ * to mask signals for the duration of the operation. _issignals_unmask()
+ * is called at the end of the operation to restore the original signal
+ * mask.
+ *
+ * _issignals_cntl() enables/disables this signal masking facility.
+ * (the default is "mask the signals").
+ *
+ * The variable already_masked is used to provide more robustness: it
+ * will prevent permanent signal masking due to bugs in the ISAM package.
+ * The permanent masking of signals would happen if _issignals_mask()
+ * were called twice in a row.
+ */
+
+
+static int      do_mask = 1;		    /* default value */
+static int      already_masked;
+static sigset_t oldmask;
+static sigset_t allsignals;
+
+
+_issignals_cntl(opt)
+    int		opt;			     /* 1 will enable masking */
+					     /* 0 will disable masking */
+{
+    int		oldmask = do_mask;
+
+    do_mask = opt ? 1 : 0;
+
+    return (oldmask);
+}
+
+_issignals_mask()
+{
+    if (do_mask && !already_masked) {
+        (void) sigfillset(&allsignals);
+        (void) sigdelset(&allsignals, SIGTRAP);
+        (void) sigdelset(&allsignals, SIGSEGV);
+        (void) sigdelset(&allsignals, SIGILL);
+        (void) sigdelset(&allsignals, SIGBUS);
+        (void) sigprocmask(SIG_SETMASK, &allsignals, &oldmask);
+	already_masked = 1;
+    }
+}
+
+_issignals_unmask()
+{
+    if (do_mask) {
+	(void)sigprocmask(SIG_SETMASK, &oldmask, NULL);
+	already_masked = 0;
+    }
+}