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/*
* libpulp - User-space Livepatching Library
*
* Copyright (C) 2020-2021 SUSE Software Solutions GmbH
*
* This file is part of libpulp.
*
* libpulp is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* libpulp is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with libpulp. If not, see <http://www.gnu.org/licenses/>.
*/
#include <errno.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <libblocked.h>
void
handler(int sig __attribute__((unused)),
siginfo_t *info __attribute__((unused)),
void *ucontext __attribute__((unused)))
{
}
void *
function1(void *arg __attribute__((unused)))
{
/* Signal readiness. */
printf("Waiting for signals.\n");
/* Call a returning library function on every interruption. */
while (1) {
pause();
hello();
}
}
void *
function2(void *arg __attribute__((unused)))
{
/* Signal readiness. */
printf("Waiting for signals.\n");
/* Call a blocking library function (unblocks on interruptions). */
while (1) {
hello_loop();
}
}
int
main(void)
{
struct sigaction act;
pthread_t thread1;
pthread_t thread2;
sigset_t set;
/* Register empty handlers for SIGUSR1 and SIGUSR2. */
memset(&act, 0, sizeof(act));
act.sa_sigaction = handler;
act.sa_flags = SA_SIGINFO;
errno = 0;
if (sigaction(SIGUSR1, &act, NULL)) {
perror("sigaction:");
return 1;
}
if (sigaction(SIGUSR2, &act, NULL)) {
perror("sigaction:");
return 1;
}
/* The main thread ignores both SIGUSR1 and SIGUSR2. */
sigemptyset(&set);
sigaddset(&set, SIGUSR1);
sigaddset(&set, SIGUSR2);
pthread_sigmask(SIG_BLOCK, &set, NULL);
/* thread1 accepts SIGUSR1, but not SIGUSR2. */
sigemptyset(&set);
sigaddset(&set, SIGUSR1);
pthread_sigmask(SIG_UNBLOCK, &set, NULL);
pthread_create(&thread1, NULL, function1, NULL);
pthread_sigmask(SIG_BLOCK, &set, NULL);
/* thread2 does the opposite. */
sigemptyset(&set);
sigaddset(&set, SIGUSR2);
pthread_sigmask(SIG_UNBLOCK, &set, NULL);
pthread_create(&thread2, NULL, function2, NULL);
pthread_sigmask(SIG_BLOCK, &set, NULL);
/* Wait for signals other than SIGUSR1 and SIGUSR2. */
while (1)
pause();
return 0;
}
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