From e2c17d2595346d1e6f7324d84fa61d99c8be6370 Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Sat, 18 Aug 2018 18:20:38 -0700
Subject: [PATCH] ircd::db: Add some arbitrary sanity checks on port
 structures.

---
 ircd/db.cc | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/ircd/db.cc b/ircd/db.cc
index eabe4d0e9..a39f4ec32 100644
--- a/ircd/db.cc
+++ b/ircd/db.cc
@@ -3190,6 +3190,13 @@ noexcept
 // Mutex
 //
 
+static_assert
+(
+	sizeof(rocksdb::port::Mutex) <= sizeof(pthread_mutex_t) + 1,
+	"link-time punning of our structure won't work if the structure is larger "
+	"than the one rocksdb has assumed space for."
+);
+
 rocksdb::port::Mutex::Mutex()
 {
 	#ifdef RB_DEBUG_DB_PORT_
@@ -3267,6 +3274,13 @@ rocksdb::port::Mutex::AssertHeld()
 // RWMutex
 //
 
+static_assert
+(
+	sizeof(rocksdb::port::RWMutex) <= sizeof(pthread_rwlock_t),
+	"link-time punning of our structure won't work if the structure is larger "
+	"than the one rocksdb has assumed space for."
+);
+
 rocksdb::port::RWMutex::RWMutex()
 {
 	#ifdef RB_DEBUG_DB_PORT_
@@ -3347,6 +3361,13 @@ rocksdb::port::RWMutex::WriteUnlock()
 // CondVar
 //
 
+static_assert
+(
+	sizeof(rocksdb::port::CondVar) <= sizeof(pthread_cond_t) + sizeof(void *),
+	"link-time punning of our structure won't work if the structure is larger "
+	"than the one rocksdb has assumed space for."
+);
+
 rocksdb::port::CondVar::CondVar(Mutex *mu)
 :mu{mu}
 {