/****************************************************************************
* apps/examples/elf/tests/signal/signal.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#ifndef USEC_PER_MSEC
# define USEC_PER_MSEC 1000L
#endif
#ifndef MSEC_PER_SEC
# define MSEC_PER_SEC 1000L
#endif
#ifndef USEC_PER_SEC
# define USEC_PER_SEC (USEC_PER_MSEC * MSEC_PER_SEC)
#endif
#define SHORT_DELAY (USEC_PER_SEC / 3)
/****************************************************************************
* Private Data
****************************************************************************/
static int sigusr1_rcvd = 0;
static int sigusr2_rcvd = 0;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: siguser_action
****************************************************************************/
/* NOTE: it is necessary for functions that are referred to by function pointers
* pointer to be declared with global scope (at least for ARM). Otherwise,
* a relocation type that is not supported by ELF is generated by GCC.
*/
void siguser_action(int signo, siginfo_t *siginfo, void *arg)
{
printf("siguser_action: Received signo=%d siginfo=%p arg=%p\n",
signo, siginfo, arg);
if (signo == SIGUSR1)
{
printf(" SIGUSR1 received\n");
sigusr2_rcvd = 1;
}
else if (signo == SIGUSR2)
{
printf(" SIGUSR2 received\n");
sigusr1_rcvd = 2;
}
else
{
printf(" ERROR: Unexpected signal\n");
}
if (siginfo)
{
printf("siginfo:\n");
printf(" si_signo = %d\n", siginfo->si_signo);
printf(" si_code = %d\n", siginfo->si_code);
printf(" si_errno = %d\n", siginfo->si_errno);
printf(" si_value = %d\n", siginfo->si_value.sival_int);
}
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: main
****************************************************************************/
int main(int argc, char **argv)
{
struct sigaction act;
struct sigaction oact1;
struct sigaction oact2;
pid_t mypid = getpid();
union sigval sigval;
int status;
printf("Setting up signal handlers from pid=%d\n", mypid);
/* Set up so that siguser_action will respond to SIGUSR1 */
memset(&act, 0, sizeof(struct sigaction));
act.sa_sigaction = siguser_action;
act.sa_flags = SA_SIGINFO;
sigemptyset(&act.sa_mask);
status = sigaction(SIGUSR1, &act, &oact1);
if (status != 0)
{
fprintf(stderr, "Failed to install SIGUSR1 handler, errno=%d\n",
errno);
exit(2);
}
printf("Old SIGUSR1 sighandler at %p\n", oact1.sa_handler);
printf("New SIGUSR1 sighandler at %p\n", siguser_action);
/* Set up so that siguser_action will respond to SIGUSR2 */
status = sigaction(SIGUSR2, &act, &oact2);
if (status != 0)
{
fprintf(stderr, "Failed to install SIGUSR2 handler, errno=%d\n",
errno);
exit(2);
}
printf("Old SIGUSR2 sighandler at %p\n", oact2.sa_handler);
printf("New SIGUSR2 sighandler at %p\n", siguser_action);
printf("Raising SIGUSR1 from pid=%d\n", mypid);
fflush(stdout); usleep(SHORT_DELAY);
/* Send SIGUSR1 to ourselves via kill() */
printf("Kill-ing SIGUSR1 from pid=%d\n", mypid);
status = kill(mypid, SIGUSR1);
if (status != 0)
{
fprintf(stderr, "Failed to kill SIGUSR1, errno=%d\n", errno);
exit(3);
}
usleep(SHORT_DELAY);
printf("SIGUSR1 raised from pid=%d\n", mypid);
/* Verify that we received SIGUSR1 */
if (sigusr1_rcvd == 0)
{
fprintf(stderr, "SIGUSR1 not received\n");
exit(4);
}
sigusr1_rcvd = 0;
/* Send SIGUSR2 to ourselves */
printf("sigqueue-ing SIGUSR2 from pid=%d\n", mypid);
fflush(stdout); usleep(SHORT_DELAY);
/* Send SIGUSR2 to ourselves via sigqueue() */
sigval.sival_int = 87;
status = sigqueue(mypid, SIGUSR2, sigval);
if (status != 0)
{
fprintf(stderr, "Failed to queue SIGUSR2, errno=%d\n", errno);
exit(5);
}
usleep(SHORT_DELAY);
printf("SIGUSR2 queued from pid=%d, sigval=87\n", mypid);
/* Verify that SIGUSR2 was received */
if (sigusr2_rcvd == 0)
{
fprintf(stderr, "SIGUSR2 not received\n");
exit(6);
}
sigusr2_rcvd = 0;
/* Remove the siguser_action handler and replace the SIGUSR2
* handler with sigusr2_sighandler.
*/
printf("Resetting SIGUSR2 signal handler from pid=%d\n", mypid);
status = sigaction(SIGUSR2, &oact2, &act);
if (status != 0)
{
fprintf(stderr, "Failed to install SIGUSR1 handler, errno=%d\n",
errno);
exit(2);
}
printf("Old SIGUSR1 sighandler at %p\n", act.sa_handler);
printf("New SIGUSR1 sighandler at %p\n", oact1.sa_handler);
/* Verify that the handler that was removed was siguser_action */
if ((void*)act.sa_handler != (void*)siguser_action)
{
fprintf(stderr,
"Old SIGUSR2 signal handler (%p) is not siguser_action (%p)\n",
act.sa_handler, siguser_action);
exit(8);
}
/* Send SIGUSR2 to ourselves via kill() */
printf("Killing SIGUSR2 from pid=%d\n", mypid);
fflush(stdout); usleep(SHORT_DELAY);
status = kill(mypid, SIGUSR2);
if (status != 0)
{
fprintf(stderr, "Failed to kill SIGUSR2, errno=%d\n", errno);
exit(9);
}
usleep(SHORT_DELAY);
printf("SIGUSR2 killed from pid=%d\n", mypid);
/* Verify that SIGUSR2 was received */
if (sigusr2_rcvd == 0)
{
fprintf(stderr, "SIGUSR2 not received\n");
exit(10);
}
sigusr2_rcvd = 0;
return 0;
}