From 68385d37def8d102b66da0cfc8f9b3d5f2a58ae8 Mon Sep 17 00:00:00 2001
From: Dirk Ziegelmeier <dirk@ziegelmeier.net>
Date: Tue, 2 Jan 2018 18:26:28 +0100
Subject: [PATCH] Work on task #14780: Add debug helper asserts to ensure
 threading/locking requirements are met Implement checks in unix port

---
 ports/unix/lib/lwipopts.h     | 23 +++++++++++++++++++-
 ports/unix/minimal/lwipopts.h | 22 +++++++++++++++++++
 ports/unix/port/sys_arch.c    | 40 ++++++++++++++++++++++++++++++++++-
 ports/unix/unixsim/lwipopts.h | 24 ++++++++++++++++++++-
 4 files changed, 106 insertions(+), 3 deletions(-)

diff --git a/ports/unix/lib/lwipopts.h b/ports/unix/lib/lwipopts.h
index 7675261..5bd79f9 100644
--- a/ports/unix/lib/lwipopts.h
+++ b/ports/unix/lib/lwipopts.h
@@ -414,6 +414,27 @@
 #define PPP_SUPPORT                     0
 
 
-/* Misc */
 
+/*
+   ---------------------------------------
+   ---------- Threading options ----------
+   ---------------------------------------
+*/
+
+#define LWIP_TCPIP_CORE_LOCKING    1
+
+#if !NO_SYS
+void sys_check_core_locking(void);
+#define LWIP_ASSERT_CORE_LOCKED()  sys_check_core_locking()
+void sys_mark_tcpip_thread(void);
+#define LWIP_MARK_TCPIP_THREAD()   sys_mark_tcpip_thread()
+
+#if LWIP_TCPIP_CORE_LOCKING
+void sys_lock_tcpip_core(void);
+#define LOCK_TCPIP_CORE()          sys_lock_tcpip_core()
+void sys_unlock_tcpip_core(void);
+#define UNLOCK_TCPIP_CORE()        sys_unlock_tcpip_core()
+#endif
+#endif
+    
 #endif /* LWIP_LWIPOPTS_H */
diff --git a/ports/unix/minimal/lwipopts.h b/ports/unix/minimal/lwipopts.h
index 3388839..e83dd47 100644
--- a/ports/unix/minimal/lwipopts.h
+++ b/ports/unix/minimal/lwipopts.h
@@ -437,4 +437,26 @@
 extern unsigned char debug_flags;
 #define LWIP_DBG_TYPES_ON debug_flags
 
+/*
+   ---------------------------------------
+   ---------- Threading options ----------
+   ---------------------------------------
+*/
+
+#define LWIP_TCPIP_CORE_LOCKING    1
+
+#if !NO_SYS
+void sys_check_core_locking(void);
+#define LWIP_ASSERT_CORE_LOCKED()  sys_check_core_locking()
+void sys_mark_tcpip_thread(void);
+#define LWIP_MARK_TCPIP_THREAD()   sys_mark_tcpip_thread()
+
+#if LWIP_TCPIP_CORE_LOCKING
+void sys_lock_tcpip_core(void);
+#define LOCK_TCPIP_CORE()          sys_lock_tcpip_core()
+void sys_unlock_tcpip_core(void);
+#define UNLOCK_TCPIP_CORE()        sys_unlock_tcpip_core()
+#endif
+#endif
+
 #endif /* LWIP_LWIPOPTS_H */
diff --git a/ports/unix/port/sys_arch.c b/ports/unix/port/sys_arch.c
index c94969b..9338531 100644
--- a/ports/unix/port/sys_arch.c
+++ b/ports/unix/port/sys_arch.c
@@ -64,6 +64,7 @@
 #include "lwip/sys.h"
 #include "lwip/opt.h"
 #include "lwip/stats.h"
+#include "lwip/tcpip.h"
 
 static void
 get_monotonic_time(struct timespec *ts)
@@ -180,6 +181,42 @@ sys_thread_new(const char *name, lwip_thread_fn function, void *arg, int stacksi
   return st;
 }
 
+#if !NO_SYS
+#if LWIP_TCPIP_CORE_LOCKING
+static u8_t lwip_core_locked;
+void sys_lock_tcpip_core(void)
+{
+   sys_mutex_lock(&lock_tcpip_core);
+   lwip_core_locked = 1;
+}
+
+void sys_unlock_tcpip_core(void)
+{
+   lwip_core_locked = 0;
+   sys_mutex_unlock(&lock_tcpip_core);
+}
+#endif /* LWIP_TCPIP_CORE_LOCKING */
+
+static pthread_t lwip_tcpip_thread_id;
+void sys_mark_tcpip_thread(void)
+{
+  lwip_tcpip_thread_id = pthread_self();
+}
+
+void sys_check_core_locking(void)
+{
+  if (lwip_tcpip_thread_id != 0) {
+    pthread_t current_thread_id = pthread_self();
+
+#if LWIP_TCPIP_CORE_LOCKING
+    LWIP_ASSERT("Function called without core lock", (current_thread_id == lwip_tcpip_thread_id) || lwip_core_locked);
+#else /* LWIP_TCPIP_CORE_LOCKING */
+    LWIP_ASSERT("Function called from wrong thread", current_thread_id == lwip_tcpip_thread_id);
+#endif /* LWIP_TCPIP_CORE_LOCKING */
+  }
+}
+#endif /* !NO_SYS */
+
 /*-----------------------------------------------------------------------------------*/
 /* Mailbox */
 err_t
@@ -639,7 +676,8 @@ sys_arch_unprotect(sys_prot_t pval)
     LWIP_UNUSED_ARG(pval);
     if (lwprot_thread == pthread_self())
     {
-        if (--lwprot_count == 0)
+        lwprot_count--;
+        if (lwprot_count == 0)
         {
             lwprot_thread = (pthread_t) 0xDEAD;
             pthread_mutex_unlock(&lwprot_mutex);
diff --git a/ports/unix/unixsim/lwipopts.h b/ports/unix/unixsim/lwipopts.h
index 1009e85..68ce048 100644
--- a/ports/unix/unixsim/lwipopts.h
+++ b/ports/unix/unixsim/lwipopts.h
@@ -369,6 +369,28 @@ extern void sntp_set_system_time(u32_t sec);
 
 #endif /* PPP_SUPPORT > 0 */
 
-#define LWIP_HTTPD_SSI          1
+#define LWIP_HTTPD_SSI  1
+
+/*
+   ---------------------------------------
+   ---------- Threading options ----------
+   ---------------------------------------
+*/
+
+#define LWIP_TCPIP_CORE_LOCKING    1
+
+#if !NO_SYS
+void sys_check_core_locking(void);
+#define LWIP_ASSERT_CORE_LOCKED()  sys_check_core_locking()
+void sys_mark_tcpip_thread(void);
+#define LWIP_MARK_TCPIP_THREAD()   sys_mark_tcpip_thread()
+
+#if LWIP_TCPIP_CORE_LOCKING
+void sys_lock_tcpip_core(void);
+#define LOCK_TCPIP_CORE()          sys_lock_tcpip_core()
+void sys_unlock_tcpip_core(void);
+#define UNLOCK_TCPIP_CORE()        sys_unlock_tcpip_core()
+#endif
+#endif
 
 #endif /* LWIP_LWIPOPTS_H */