su: fix exit status if terminated by signal

[kzak@redhat.com: - add comment]

Signed-off-by: Ondrej Oprala <ooprala@redhat.com>
Signed-off-by: Karel Zak <kzak@redhat.com>

login-utils/su-common.c

@@ -232,9 +232,9 @@ cleanup_pam (int retcode)

/* Signal handler for parent process.  */
static void
su_catch_sig (int sig __attribute__((__unused__)))
su_catch_sig (int sig)
{
  caught_signal = true;
  caught_signal = sig;
}

/* Export env variables declared by PAM modules.  */
@@ -258,6 +258,7 @@ create_watching_parent (void)
{
  pid_t child;
  sigset_t ourset;
  struct sigaction oldact[3];
  int status = 0;
  int retval;

@@ -312,13 +313,13 @@ create_watching_parent (void)
      }
    if (!caught_signal && (sigaddset(&ourset, SIGTERM)
                    || sigaddset(&ourset, SIGALRM)
                    || sigaction(SIGTERM, &action, NULL)
                    || sigaction(SIGTERM, &action, &oldact[0])
                    || sigprocmask(SIG_UNBLOCK, &ourset, NULL))) {
	  warn (_("cannot set signal handler"));
	  caught_signal = true;
	}
    if (!caught_signal && !same_session && (sigaction(SIGINT, &action, NULL)
                                     || sigaction(SIGQUIT, &action, NULL)))
    if (!caught_signal && !same_session && (sigaction(SIGINT, &action, &oldact[1])
                                     || sigaction(SIGQUIT, &action, &oldact[2])))
      {
        warn (_("cannot set signal handler"));
        caught_signal = true;
@@ -341,17 +342,21 @@ create_watching_parent (void)
	    break;
	}
      if (pid != (pid_t)-1)
	if (WIFSIGNALED (status))
	  {
	    status = WTERMSIG (status) + 128;
	    if (WCOREDUMP (status))
	      fprintf (stderr, _("%s (core dumped)\n"),
                 strsignal (WTERMSIG (status)));
	  }
	else
	  status = WEXITSTATUS (status);
        {
          if (WIFSIGNALED (status))
            {
              status = WTERMSIG (status) + 128;
              if (WCOREDUMP (status))
                fprintf (stderr, _("%s (core dumped)\n"),
                   strsignal (WTERMSIG (status)));
            }
          else
            status = WEXITSTATUS (status);
        }
      else if (caught_signal)
        status = caught_signal + 128;
      else
	status = 1;
        status = 1;
    }
  else
    status = 1;
@@ -369,6 +374,27 @@ create_watching_parent (void)
      sleep (2);
      kill (child, SIGKILL);
      fprintf (stderr, _(" ...killed.\n"));

      /* Let's terminate itself with the received signal.
       *
       * It seems that shells use WIFSIGNALED() rather than our exit status
       * value to detect situations when is necessary to cleanup (reset)
       * terminal settings (kzak -- Jun 2013).
       */
      switch (caught_signal) {
        case SIGTERM:
          sigaction(SIGTERM, &oldact[0], NULL);
          break;
        case SIGINT:
          sigaction(SIGINT, &oldact[1], NULL);
          break;
        case SIGQUIT:
          sigaction(SIGQUIT, &oldact[2], NULL);
          break;
        default:
          break;
      }
      kill(0, caught_signal);
    }
  exit (status);
}

login-utils/su.1

@@ -135,6 +135,15 @@ Display help text and exit.
.TP
\fB\-\-version\fR
Display version information and exit.
.SH SIGNALS
Upon receiving either
.BR SIGINT ,
.BR SIGQUIT
or
.BR SIGTERM ,
.BR su
terminates it's child and afterwards terminates itself with
the received signal.
.SH CONFIG FILES
.B su
reads the