No need to restore default signal handler for SIGSTOP as it is not

catchable.  Attempting to do so is harmless but sigaction() will
fail and set errno to EINVAL which makes it looks like there is an
error.

diff --git a/src/exec_pty.c b/src/exec_pty.c
index 403928360de480062362c59f5acf357e4fd0d731..a80dbb20d908fd461522e1ee0262464d1d253389 100644 (file)
--- a/src/exec_pty.c
+++ b/src/exec_pty.c
@@ -388,11 +388,13 @@ suspend_parent(int signo)
            snprintf(signame, sizeof(signame), "%d", signo);
 
        /* Suspend self and continue command when we resume. */
-       zero_bytes(&sa, sizeof(sa));
-       sigemptyset(&sa.sa_mask);
-       sa.sa_flags = SA_INTERRUPT; /* do not restart syscalls */
-       sa.sa_handler = SIG_DFL;
-       sigaction(signo, &sa, &osa);
+       if (signo != SIGSTOP) {
+           zero_bytes(&sa, sizeof(sa));
+           sigemptyset(&sa.sa_mask);
+           sa.sa_flags = SA_INTERRUPT; /* do not restart syscalls */
+           sa.sa_handler = SIG_DFL;
+           sigaction(signo, &sa, &osa);
+       }
        sudo_debug_printf(SUDO_DEBUG_INFO, "kill parent SIG%s", signame);
        if (killpg(ppgrp, signo) != 0)
            warning("killpg(%d, SIG%s)", (int)ppgrp, signame);
@@ -419,7 +421,8 @@ suspend_parent(int signo)
            }
        }
 
-       sigaction(signo, &osa, NULL);
+       if (signo != SIGSTOP)
+           sigaction(signo, &osa, NULL);
        rval = ttymode == TERM_RAW ? SIGCONT_FG : SIGCONT_BG;
        break;
     }