See if SA_RESTART signals will interrupt select().

On some platforms (at least older HP-UXes such as 11.11, possibly others)
setting SA_RESTART on signal handers will cause it to not interrupt
select(), at least for calls that do not specify a timeout.  Try to
detect this and if found, don't use SA_RESTART.

POSIX says "If SA_RESTART has been set for the interrupting signal, it
is implementation-dependent whether select() restarts or returns with
[EINTR]" so this behaviour is within spec.

1 files changed, 2 insertions, 0 deletions

diff --git a/misc.c b/misc.c
index 506507226..554ceb0b1 100644
--- a/misc.c
+++ b/misc.c
@@ -2258,8 +2258,10 @@ ssh_signal(int signum, sshsig_t handler)
         memset(&sa, 0, sizeof(sa));
         sa.sa_handler = handler;
         sigfillset(&sa.sa_mask);
+#if defined(SA_RESTART) && !defined(NO_SA_RESTART)
         if (signum != SIGALRM)
                 sa.sa_flags = SA_RESTART;
+#endif
         if (sigaction(signum, &sa, &osa) == -1) {
                 debug3("sigaction(%s): %s", strsignal(signum), strerror(errno));
                 return SIG_ERR;