From 24493e9169d3058958ab3ec4d2b02c5753954981 Mon Sep 17 00:00:00 2001
From: Maria Matejka <mq@ucw.cz>
Date: Fri, 4 Oct 2019 12:20:02 +0200
Subject: [PATCH] Fixed undefined behavior on signals.

The C11 specification allows only sig_atomic_t and _Atomic variable
access. All other accesses to global variables are undefined behavior.

Using int was probably OK on x86 and x86_64; yet there were some reports
from other architectures (especially some MIPS) that in rare cases,
after issuing SIGHUP, BIRD did strange things.
---
 sysdep/unix/io.c   | 4 ----
 sysdep/unix/main.c | 6 +++---
 sysdep/unix/unix.h | 7 ++++---
 test/birdtest.c    | 5 +++++
 4 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/sysdep/unix/io.c b/sysdep/unix/io.c
index c9fee3ab..5e4d9573 100644
--- a/sysdep/unix/io.c
+++ b/sysdep/unix/io.c
@@ -2154,10 +2154,6 @@ watchdog_stop(void)
  *	Main I/O Loop
  */
 
-volatile int async_config_flag;		/* Asynchronous reconfiguration/dump scheduled */
-volatile int async_dump_flag;
-volatile int async_shutdown_flag;
-
 void
 io_init(void)
 {
diff --git a/sysdep/unix/main.c b/sysdep/unix/main.c
index db848033..a52ae3ca 100644
--- a/sysdep/unix/main.c
+++ b/sysdep/unix/main.c
@@ -601,9 +601,9 @@ cmd_graceful_restart(void)
  *	Signals
  */
 
-volatile int async_config_flag;
-volatile int async_dump_flag;
-volatile int async_shutdown_flag;
+volatile sig_atomic_t async_config_flag;
+volatile sig_atomic_t async_dump_flag;
+volatile sig_atomic_t async_shutdown_flag;
 
 static void
 handle_sighup(int sig UNUSED)
diff --git a/sysdep/unix/unix.h b/sysdep/unix/unix.h
index bf0aedeb..bd817bf2 100644
--- a/sysdep/unix/unix.h
+++ b/sysdep/unix/unix.h
@@ -10,6 +10,7 @@
 #define _BIRD_UNIX_H_
 
 #include <sys/socket.h>
+#include <signal.h>
 
 struct pool;
 struct iface;
@@ -97,9 +98,9 @@ int sockaddr_read(sockaddr *sa, int af, ip_addr *a, struct iface **ifa, uint *po
 #define SUN_LEN(ptr) ((size_t) (((struct sockaddr_un *) 0)->sun_path) + strlen ((ptr)->sun_path))
 #endif
 
-extern volatile int async_config_flag;
-extern volatile int async_dump_flag;
-extern volatile int async_shutdown_flag;
+extern volatile sig_atomic_t async_config_flag;
+extern volatile sig_atomic_t async_dump_flag;
+extern volatile sig_atomic_t async_shutdown_flag;
 
 void io_init(void);
 void io_loop(void);
diff --git a/test/birdtest.c b/test/birdtest.c
index c0d4bd05..484205d2 100644
--- a/test/birdtest.c
+++ b/test/birdtest.c
@@ -36,6 +36,11 @@ static int no_fork;
 static int no_timeout;
 static int is_terminal;		/* Whether stdout is a live terminal or pipe redirect */
 
+volatile sig_atomic_t async_config_flag;		/* Asynchronous reconfiguration/dump scheduled */
+volatile sig_atomic_t async_dump_flag;
+volatile sig_atomic_t async_shutdown_flag;
+
+
 uint bt_verbose;
 const char *bt_filename;
 const char *bt_test_id;