signals.c

#include <stdio.h>
#include <unistd.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>

#define NUMSIGS 64
#define MULTIPLE_OF_(x, i) (i % x == 0)

void (sig_handler) (int);

int sig_count[NUMSIGS + 1];
volatile static int line;
volatile int signumbuf[NUMSIGS * 100], sigcountbuf[NUMSIGS * 100];

int main(int argc, char* argv[]) {
  sigset_t sigmask_new, sigmask_old;
  struct sigaction sigact, oldact;
  int signum, rc, i;

  rc = sigfillset(&sigmask_new);
  rc = sigprocmask(SIG_SETMASK, &sigmask_new, &sigmask_old);

  memset(&sigact, 0, sizeof(struct sigaction));
  sigact.sa_handler = sig_handler;
  sigact.sa_flags   = 0;
  sigact.sa_mask    = sigmask_new;

  printf("\nInstalling signal handler and Raising signal for signal number: \n\n");
  for (signum = 1; signum <= NUMSIGS; signum++) {
    if (signum == SIGKILL || signum == SIGSTOP || signum == 32 || signum == 33) {
      printf("  --");
    } else {
      sigaction(signum, &sigact, &oldact);
      rc = raise(signum);
      rc = raise(signum);
      rc = raise(signum);
      if (rc) {
        printf("Failed on Signal %d\n", signum);
      } else {
        printf("%4d", signum);
      }
    }

    if (MULTIPLE_OF_(16, signum))
      printf("\n");
  }

  fflush(stdout);

  rc = sigprocmask(SIG_SETMASK, &sigmask_old, NULL);
  printf("\nSignal Number(Times Processed)\n");
  printf("---------------------------------------------------\n");
  for (i = 1; i <= NUMSIGS; i++) {
    printf("%4d: %3d  ", i, sig_count[i]);
    if (MULTIPLE_OF_(8, i))
      printf("\n");
  }
  printf("\n");

  printf("\nHistory: Signal Number(Count Processed)\n");
  printf("---------------------------------------------------\n");
  for (i = 0; i < line; i++) {
    if (MULTIPLE_OF_(8, i))
      printf("\n");
    printf("%4d(%1d)", signumbuf[i], sigcountbuf[i]);
  }

  printf("\n");
  exit(EXIT_SUCCESS);
}

void sig_handler(int sig) {
  sig_count[sig]++;
  signumbuf[line] = sig;
  sigcountbuf[line] = sig_count[sig];
  line++;
}