From f92d862c1af230a873c2b2d30fea575ff3dafd56 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn-Egil=20Dahlberg?= <egil@erlang.org>
Date: Tue, 21 Mar 2017 14:37:03 +0100
Subject: erts: Make sigterm signal safe for non-smp beam

The signal handler will now schedule a sigterm message instead of sending
the message in the signal handler. The signal handler must refrain from
memory allocations and thus the event is scheduled.
---
 erts/emulator/sys/common/erl_check_io.c | 10 ++++++++++
 erts/emulator/sys/unix/sys.c            | 20 +++++++++++++++++---
 2 files changed, 27 insertions(+), 3 deletions(-)

(limited to 'erts/emulator/sys')

diff --git a/erts/emulator/sys/common/erl_check_io.c b/erts/emulator/sys/common/erl_check_io.c
index 44a77f3ea5..8f2f1f9521 100644
--- a/erts/emulator/sys/common/erl_check_io.c
+++ b/erts/emulator/sys/common/erl_check_io.c
@@ -1617,6 +1617,11 @@ ERTS_CIO_EXPORT(erts_check_io)(int do_wait)
 	erts_do_break_handling();
 #endif
 
+#ifdef ERTS_SIGNAL_SIGTERM
+    if (ERTS_SIGNAL_SIGTERM)
+	erts_handle_signal_sigterm();
+#endif
+
     /* Figure out timeout value */
     timeout_time = (do_wait
 		    ? erts_check_next_timeout_time(esdp)
@@ -1654,6 +1659,11 @@ ERTS_CIO_EXPORT(erts_check_io)(int do_wait)
 	erts_do_break_handling();
 #endif
 
+#ifdef ERTS_SIGNAL_SIGTERM
+    if (ERTS_SIGNAL_SIGTERM)
+	erts_handle_signal_sigterm();
+#endif
+
     if (poll_ret != 0) {
 	erts_smp_atomic_set_nob(&pollset.in_poll_wait, 0);
 	forget_removed(&pollset);
diff --git a/erts/emulator/sys/unix/sys.c b/erts/emulator/sys/unix/sys.c
index 6459fa064b..55411f83d0 100644
--- a/erts/emulator/sys/unix/sys.c
+++ b/erts/emulator/sys/unix/sys.c
@@ -148,11 +148,18 @@ volatile int erts_break_requested = 0;
 #define ERTS_SET_BREAK_REQUESTED (erts_break_requested = 1)
 #define ERTS_UNSET_BREAK_REQUESTED (erts_break_requested = 0)
 #endif
+
+#ifndef ERTS_SMP
+volatile Uint erts_signal_sigterm = 0;
+#define ERTS_SET_SIGNAL_SIGTERM (erts_signal_sigterm = 1)
+#define ERTS_CLEAR_SIGNAL_SIGTERM (erts_signal_sigterm = 0)
+#endif
+
 /* set early so the break handler has access to initial mode */
 static struct termios initial_tty_mode;
 static int replace_intr = 0;
 /* assume yes initially, ttsl_init will clear it */
-int using_oldshell = 1; 
+int using_oldshell = 1;
 
 #ifdef ERTS_ENABLE_KERNEL_POLL
 
@@ -684,11 +691,11 @@ static RETSIGTYPE request_stop(int signum)
 #ifdef ERTS_SMP
     smp_sig_notify('S');
 #else
-    stop_requested();
+    ERTS_SET_SIGNAL_SIGTERM;
+    ERTS_CHK_IO_AS_INTR();
 #endif
 }
 
-
 static ERTS_INLINE void
 sigusr1_exit(void)
 {
@@ -958,6 +965,13 @@ void erts_do_break_handling(void)
     erts_smp_thr_progress_unblock();
 }
 
+#ifdef ERTS_SIGNAL_SIGTERM
+void erts_handle_signal_sigterm(void) {
+    ERTS_CLEAR_SIGNAL_SIGTERM;
+    stop_requested();
+}
+#endif
+
 /* Fills in the systems representation of the jam/beam process identifier.
 ** The Pid is put in STRING representation in the supplied buffer,
 ** no interpretatione of this should be done by the rest of the
-- 
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