From 5e61585d76ae77fd5e9e96ebabb57afa4d74880d Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 14:06:34 +0200 Subject: Adding upstream version 3.5.24. Signed-off-by: Daniel Baumann --- src/util/sigdelay.c | 118 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 118 insertions(+) create mode 100644 src/util/sigdelay.c (limited to 'src/util/sigdelay.c') diff --git a/src/util/sigdelay.c b/src/util/sigdelay.c new file mode 100644 index 0000000..6f07a22 --- /dev/null +++ b/src/util/sigdelay.c @@ -0,0 +1,118 @@ +/*++ +/* NAME +/* sigdelay 3 +/* SUMMARY +/* delay/resume signal delivery +/* SYNOPSIS +/* #include +/* +/* 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 +#include + +/* 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 +#include +#include + +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 -- cgit v1.2.3