grrr

signal2.c

#include <signal.h>
#include <unistd.h>
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <bits/signum.h>
#include <string.h>

int pipefd[2];
#define RPIPE 0
#define WPIPE 1
void send_sig(int signal) { 
    write(pipefd[WPIPE], &signal, 1);
}
void pr_pending(sigset_t * pendmask) {
    int signo=_NSIG;
    while(--signo) {
        if( sigismember(pendmask, signo)) {
            printf("%s is pending\n", _sys_siglist[signo]); 
        }
    }
}
typedef struct {
    int signo;
    int offset;
} sig2off;

int main(void) {
    sigset_t mask, oldmask, pendmask,zmask;
    int signal_received=0;
    struct sigaction sa,old_sa;
    int sig2off[_NSIG];
    int i = 0;
    int val=0;
    for(i=0;i<_NSIG;i++){
        sig2off[i]=-1;
    }
    sig2off[SIGALRM]=0;
    sig2off[SIGUSR2]=1;
    sig2off[SIGINT]=2;

    sa.sa_handler=&send_sig;
    sa.sa_flags |= SA_INTERRUPT;
    //sa.sa_flags |= SA_RESTART;
    sigemptyset(&mask);
    sigemptyset(&oldmask);
    sigemptyset(&zmask);
    sigaddset(&mask,SIGUSR1);
    sigaddset(&mask,SIGHUP);
    for(i=0;i<_NSIG;i++){
        if(sig2off[i]>=0){
            sigaddset(&mask,sig2off[i]);
        }
    }


    pipe(pipefd);
    fcntl(pipefd[RPIPE],F_SETFD, O_NONBLOCK);
    fcntl(pipefd[WPIPE],F_SETFD, O_NONBLOCK);
    i=SIGHUP;
    printf("installing signal %d(%s)\n",i, strsignal(i));
    sigaction(SIGHUP, &sa,NULL);//,&old_sa);
    i=SIGUSR1;
    printf("installing signal %d(%s)\n",i, strsignal(i));
    sigaction(SIGUSR1,&sa,NULL);// &old_sa);
    for(i=0;i<_NSIG;i++){
        if(sig2off[i]>=0){
            sigaction(i, &sa,NULL);// &old_sa);
            printf("installing signal %d(%s)\n",i, strsignal(i));
        }
    }

    //for(;;) {
    while(pause()){
        //sigsuspend(&zmask);
        //pr_pending(&pendmask);
        sigprocmask (SIG_BLOCK, &mask,NULL);// &oldmask);
        printf("%s","processing\0");
        char buf[1];
        while(read(pipefd[RPIPE],buf,1) !=0 ){//||  errno != EINTR){
            int signo=(int)*buf;
            printf("[%d]received sig%d==%d\n",++signal_received, (int )*buf,signo);
            printf("E:%d\n", errno);
            if(SIGHUP==signo){
                printf("ACK val=%d\n", val);
            } else if(SIGUSR1==signo){
                val=0;
                printf("CLR val=%d\n",val);
            }else{
                val|=1<<sig2off[signo];
                printf("SFT shift %d bit val is %d\n",sig2off[signo], val);
            }
        }
        //pr_pending(&pendmask);
        sigprocmask (SIG_UNBLOCK, &mask, NULL);
    }
}