From e9fe4f33bb04ca5c050d04ea4ba24e3b9deb7a53 Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Mon, 21 Feb 2022 11:03:21 -0800
Subject: [PATCH] configure: Check for mprotect(2).

---
 configure.ac      |  1 +
 ircd/allocator.cc | 12 ++++++++++++
 2 files changed, 13 insertions(+)

diff --git a/configure.ac b/configure.ac
index 4a29b2195..8be2d6dac 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1188,6 +1188,7 @@ AC_CHECK_FUNCS([          \
 	mlock                 \
 	mlock2                \
 	mmap                  \
+	mprotect              \
 	msync                 \
 	posix_fadvise         \
 	posix_madvise         \
diff --git a/ircd/allocator.cc b/ircd/allocator.cc
index 16f8983b0..e43bbdd16 100644
--- a/ircd/allocator.cc
+++ b/ircd/allocator.cc
@@ -138,6 +138,7 @@ catch(const std::exception &e)
 void
 ircd::allocator::readonly(const mutable_buffer &buf,
                           const bool enable)
+#if defined(HAVE_MPROTECT)
 {
 	const int prot
 	{
@@ -149,7 +150,13 @@ ircd::allocator::readonly(const mutable_buffer &buf,
 	void *const ptr(mutable_cast(data(buf)));
 	sys::call(::mprotect, ptr, size(buf), prot);
 }
+#else
+{
+	#warning "mprotect(2) not available for this compilation."
+}
+#endif
 
+#if defined(HAVE_MPROTECT)
 void
 ircd::allocator::protect(const const_buffer &buf,
                          const bool enable)
@@ -164,6 +171,11 @@ ircd::allocator::protect(const const_buffer &buf,
 	void *const ptr(mutable_cast(data(buf)));
 	sys::call(::mprotect, ptr, size(buf), prot);
 }
+#else
+{
+	#warning "mprotect(2) not available for this compilation."
+}
+#endif
 
 size_t
 ircd::allocator::sync(const const_buffer &buf,