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-rw-r--r--src/util/sigdelay.c118
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diff --git a/src/util/sigdelay.c b/src/util/sigdelay.c
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+/*++
+/* NAME
+/* sigdelay 3
+/* SUMMARY
+/* delay/resume signal delivery
+/* SYNOPSIS
+/* #include <sigdelay.h>
+/*
+/* void sigdelay()
+/*
+/* void sigresume()
+/* DESCRIPTION
+/* sigdelay() delays delivery of signals. Signals that
+/* arrive in the mean time will be queued.
+/*
+/* sigresume() resumes delivery of signals. Signals that have
+/* arrived in the mean time will be delivered.
+/* DIAGNOSTICS
+/* All errors are fatal.
+/* BUGS
+/* The signal queue may be really short (as in: one per signal type).
+/*
+/* Some signals such as SIGKILL cannot be blocked.
+/* LICENSE
+/* .ad
+/* .fi
+/* The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/* Wietse Venema
+/* IBM T.J. Watson Research
+/* P.O. Box 704
+/* Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <signal.h>
+
+/* Utility library. */
+
+#include "msg.h"
+#include "posix_signals.h"
+#include "sigdelay.h"
+
+/* Application-specific. */
+
+static sigset_t saved_sigmask;
+static sigset_t block_sigmask;
+static int suspending;
+static int siginit_done;
+
+/* siginit - compute signal mask only once */
+
+static void siginit(void)
+{
+ int sig;
+
+ siginit_done = 1;
+ sigemptyset(&block_sigmask);
+ for (sig = 1; sig < NSIG; sig++)
+ sigaddset(&block_sigmask, sig);
+}
+
+/* sigresume - deliver delayed signals and disable signal delay */
+
+void sigresume(void)
+{
+ if (suspending != 0) {
+ suspending = 0;
+ if (sigprocmask(SIG_SETMASK, &saved_sigmask, (sigset_t *) 0) < 0)
+ msg_fatal("sigresume: sigprocmask: %m");
+ }
+}
+
+/* sigdelay - save signal mask and block all signals */
+
+void sigdelay(void)
+{
+ if (siginit_done == 0)
+ siginit();
+ if (suspending == 0) {
+ suspending = 1;
+ if (sigprocmask(SIG_BLOCK, &block_sigmask, &saved_sigmask) < 0)
+ msg_fatal("sigdelay: sigprocmask: %m");
+ }
+}
+
+#ifdef TEST
+
+ /*
+ * Test program - press Ctrl-C twice while signal delivery is delayed, and
+ * see how many signals are delivered when signal delivery is resumed.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+static void gotsig(int sig)
+{
+ printf("Got signal %d\n", sig);
+}
+
+int main(int unused_argc, char **unused_argv)
+{
+ signal(SIGINT, gotsig);
+ signal(SIGQUIT, gotsig);
+
+ printf("Delaying signal delivery\n");
+ sigdelay();
+ sleep(5);
+ printf("Resuming signal delivery\n");
+ sigresume();
+ exit(0);
+}
+
+#endif