From 43c549305bdb0770a3fbebe7347b3da8b2d9ceec Mon Sep 17 00:00:00 2001
From: Yong Cong Sin <ycsin@meta.com>
Date: Tue, 18 Jul 2023 13:00:59 +0800
Subject: [PATCH] posix: signal: check RTSIG limit

Use build assert to make sure that the realtime signal
constants are configured properly in the Kconfig.

Signed-off-by: Yong Cong Sin <ycsin@meta.com>
---
 lib/posix/Kconfig        |  1 +
 lib/posix/Kconfig.limits | 13 +++++++++++++
 lib/posix/signal.c       |  3 +++
 3 files changed, 17 insertions(+)
 create mode 100644 lib/posix/Kconfig.limits

diff --git a/lib/posix/Kconfig b/lib/posix/Kconfig
index 59414797328c1e..199ed956af2503 100644
--- a/lib/posix/Kconfig
+++ b/lib/posix/Kconfig
@@ -44,6 +44,7 @@ source "lib/posix/Kconfig.fnmatch"
 source "lib/posix/Kconfig.fs"
 source "lib/posix/Kconfig.getopt"
 source "lib/posix/Kconfig.key"
+source "lib/posix/Kconfig.limits"
 source "lib/posix/Kconfig.mqueue"
 source "lib/posix/Kconfig.mutex"
 source "lib/posix/Kconfig.pthread"
diff --git a/lib/posix/Kconfig.limits b/lib/posix/Kconfig.limits
new file mode 100644
index 00000000000000..cc651203961c8f
--- /dev/null
+++ b/lib/posix/Kconfig.limits
@@ -0,0 +1,13 @@
+# Copyright (c) 2023 Meta
+#
+# SPDX-License-Identifier: Apache-2.0
+
+if POSIX_SIGNAL
+config POSIX_LIMITS_RTSIG_MAX
+	int "_POSIX_RTSIG_MAX value in limits.h"
+	default 8
+	help
+	  Define the _POSIX_RTSIG_MAX value in limits.h.
+	  IEEE 1003.1 defines this to be 8.
+
+endif
diff --git a/lib/posix/signal.c b/lib/posix/signal.c
index e1d7feab299d93..809ba84dc3a6e6 100644
--- a/lib/posix/signal.c
+++ b/lib/posix/signal.c
@@ -13,6 +13,9 @@
 #define SIGNO_WORD_IDX(_signo) (signo / BITS_PER_LONG)
 #define SIGNO_WORD_BIT(_signo) (signo & BIT_MASK(LOG2(BITS_PER_LONG)))
 
+BUILD_ASSERT(CONFIG_POSIX_LIMITS_RTSIG_MAX >= 0);
+BUILD_ASSERT(CONFIG_POSIX_RTSIG_MAX >= CONFIG_POSIX_LIMITS_RTSIG_MAX);
+
 static inline bool signo_valid(int signo)
 {
 	return ((signo > 0) && (signo < _NSIG));