putty/unix/uxsignal.c

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

/*
 * Calling signal() is non-portable, as it varies in meaning
 * between platforms and depending on feature macros, and has
 * stupid semantics at least some of the time.
 *
 * This function provides the same interface as the libc function,
 * but provides consistent semantics.  It assumes POSIX semantics
 * for sigaction() (so you might need to do some more work if you
 * port to something ancient like SunOS 4)
 */
void (*putty_signal(int sig, void (*func)(int)))(int) {
    struct sigaction sa;
    struct sigaction old;
    
    sa.sa_handler = func;
    if(sigemptyset(&sa.sa_mask) < 0)
	return SIG_ERR;
    sa.sa_flags = SA_RESTART;
    if(sigaction(sig, &sa, &old) < 0)
	return SIG_ERR;
    return old.sa_handler;
}

void block_signal(int sig, int block_it)
{
    sigset_t ss;

    sigemptyset(&ss);
    sigaddset(&ss, sig);
    if(sigprocmask(block_it ? SIG_BLOCK : SIG_UNBLOCK, &ss, 0) < 0) {
	perror("sigprocmask");
	exit(1);
    }
}

/*
Local Variables:
c-basic-offset:4
comment-column:40
End:
*/