Programming

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>

struct sigaction oldHandler;

void myHandler(int sig,  siginfo_t *siginfo, void *context) {
// if i have not written any code inside this function, the program will give a feel of hang( this functions is getting continuously called
        if(siginfo->si_code == SEGV_MAPERR)
        {
                write(1,"address not mapped to object",strlen("address not mapped to object"));
        }
        else if (siginfo->si_code == SEGV_ACCERR)
        {
                write(1,"invalid permissions for mapped object",strlen("invalid permissions for mapped object"));
        }

       write(1,"\n",1);

 //        exit(0); if this exit(0) is not present, program will get continuous calls to this signal handler
        return;
}

int main(int argc, char *argv[]) {

    /* Install mySignalHandler for SIGSEGV */
    struct sigaction sigAct;
    int              status = 0;
    char *addr = NULL;

    sigAct.sa_handler   = 0;
    sigAct.sa_sigaction = myHandler;
    sigfillset(&sigAct.sa_mask);
    sigAct.sa_flags = SA_SIGINFO;

    status = sigaction(SIGSEGV, &sigAct, &oldHandler);
    if (status != 0) {
        perror("Failed to install handler for signal SIGSEGV");
        exit(1);
    }
#if 1
    /* This will invoke the signal handler */
// addr = malloc(strlen("Hello"));
     strcpy(addr,"Hello");
    printf("%s\n",addr);

#endif
        printf("Returning from main\n");
    return 0;
}