1*41fbaed0Stron /* $NetBSD: sigdelay.c,v 1.1.1.1 2009/06/23 10:09:00 tron Exp $ */
2*41fbaed0Stron
3*41fbaed0Stron /*++
4*41fbaed0Stron /* NAME
5*41fbaed0Stron /* sigdelay 3
6*41fbaed0Stron /* SUMMARY
7*41fbaed0Stron /* delay/resume signal delivery
8*41fbaed0Stron /* SYNOPSIS
9*41fbaed0Stron /* #include <sigdelay.h>
10*41fbaed0Stron /*
11*41fbaed0Stron /* void sigdelay()
12*41fbaed0Stron /*
13*41fbaed0Stron /* void sigresume()
14*41fbaed0Stron /* DESCRIPTION
15*41fbaed0Stron /* sigdelay() delays delivery of signals. Signals that
16*41fbaed0Stron /* arrive in the mean time will be queued.
17*41fbaed0Stron /*
18*41fbaed0Stron /* sigresume() resumes delivery of signals. Signals that have
19*41fbaed0Stron /* arrived in the mean time will be delivered.
20*41fbaed0Stron /* DIAGNOSTICS
21*41fbaed0Stron /* All errors are fatal.
22*41fbaed0Stron /* BUGS
23*41fbaed0Stron /* The signal queue may be really short (as in: one per signal type).
24*41fbaed0Stron /*
25*41fbaed0Stron /* Some signals such as SIGKILL cannot be blocked.
26*41fbaed0Stron /* LICENSE
27*41fbaed0Stron /* .ad
28*41fbaed0Stron /* .fi
29*41fbaed0Stron /* The Secure Mailer license must be distributed with this software.
30*41fbaed0Stron /* AUTHOR(S)
31*41fbaed0Stron /* Wietse Venema
32*41fbaed0Stron /* IBM T.J. Watson Research
33*41fbaed0Stron /* P.O. Box 704
34*41fbaed0Stron /* Yorktown Heights, NY 10598, USA
35*41fbaed0Stron /*--*/
36*41fbaed0Stron
37*41fbaed0Stron /* System library. */
38*41fbaed0Stron
39*41fbaed0Stron #include <sys_defs.h>
40*41fbaed0Stron #include <signal.h>
41*41fbaed0Stron
42*41fbaed0Stron /* Utility library. */
43*41fbaed0Stron
44*41fbaed0Stron #include "msg.h"
45*41fbaed0Stron #include "posix_signals.h"
46*41fbaed0Stron #include "sigdelay.h"
47*41fbaed0Stron
48*41fbaed0Stron /* Application-specific. */
49*41fbaed0Stron
50*41fbaed0Stron static sigset_t saved_sigmask;
51*41fbaed0Stron static sigset_t block_sigmask;
52*41fbaed0Stron static int suspending;
53*41fbaed0Stron static int siginit_done;
54*41fbaed0Stron
55*41fbaed0Stron /* siginit - compute signal mask only once */
56*41fbaed0Stron
siginit(void)57*41fbaed0Stron static void siginit(void)
58*41fbaed0Stron {
59*41fbaed0Stron int sig;
60*41fbaed0Stron
61*41fbaed0Stron siginit_done = 1;
62*41fbaed0Stron sigemptyset(&block_sigmask);
63*41fbaed0Stron for (sig = 1; sig < NSIG; sig++)
64*41fbaed0Stron sigaddset(&block_sigmask, sig);
65*41fbaed0Stron }
66*41fbaed0Stron
67*41fbaed0Stron /* sigresume - deliver delayed signals and disable signal delay */
68*41fbaed0Stron
sigresume(void)69*41fbaed0Stron void sigresume(void)
70*41fbaed0Stron {
71*41fbaed0Stron if (suspending != 0) {
72*41fbaed0Stron suspending = 0;
73*41fbaed0Stron if (sigprocmask(SIG_SETMASK, &saved_sigmask, (sigset_t *) 0) < 0)
74*41fbaed0Stron msg_fatal("sigresume: sigprocmask: %m");
75*41fbaed0Stron }
76*41fbaed0Stron }
77*41fbaed0Stron
78*41fbaed0Stron /* sigdelay - save signal mask and block all signals */
79*41fbaed0Stron
sigdelay(void)80*41fbaed0Stron void sigdelay(void)
81*41fbaed0Stron {
82*41fbaed0Stron if (siginit_done == 0)
83*41fbaed0Stron siginit();
84*41fbaed0Stron if (suspending == 0) {
85*41fbaed0Stron suspending = 1;
86*41fbaed0Stron if (sigprocmask(SIG_BLOCK, &block_sigmask, &saved_sigmask) < 0)
87*41fbaed0Stron msg_fatal("sigdelay: sigprocmask: %m");
88*41fbaed0Stron }
89*41fbaed0Stron }
90*41fbaed0Stron
91*41fbaed0Stron #ifdef TEST
92*41fbaed0Stron
93*41fbaed0Stron /*
94*41fbaed0Stron * Test program - press Ctrl-C twice while signal delivery is delayed, and
95*41fbaed0Stron * see how many signals are delivered when signal delivery is resumed.
96*41fbaed0Stron */
97*41fbaed0Stron
98*41fbaed0Stron #include <stdio.h>
99*41fbaed0Stron #include <unistd.h>
100*41fbaed0Stron #include <stdlib.h>
101*41fbaed0Stron
gotsig(int sig)102*41fbaed0Stron static void gotsig(int sig)
103*41fbaed0Stron {
104*41fbaed0Stron printf("Got signal %d\n", sig);
105*41fbaed0Stron }
106*41fbaed0Stron
main(int unused_argc,char ** unused_argv)107*41fbaed0Stron int main(int unused_argc, char **unused_argv)
108*41fbaed0Stron {
109*41fbaed0Stron signal(SIGINT, gotsig);
110*41fbaed0Stron signal(SIGQUIT, gotsig);
111*41fbaed0Stron
112*41fbaed0Stron printf("Delaying signal delivery\n");
113*41fbaed0Stron sigdelay();
114*41fbaed0Stron sleep(5);
115*41fbaed0Stron printf("Resuming signal delivery\n");
116*41fbaed0Stron sigresume();
117*41fbaed0Stron exit(0);
118*41fbaed0Stron }
119*41fbaed0Stron
120*41fbaed0Stron #endif
121