From e77787adef5cb688c86252a92d4bf34948fa131a Mon Sep 17 00:00:00 2001
From: Perry Werneck <perry.werneck@gmail.com>
Date: Tue, 12 Feb 2019 13:50:57 -0200
Subject: [PATCH] Fixing linked list management error when removing st callbacks.

---
 src/include/lib3270.h |  2 +-
 src/lib3270/connect.c |  2 ++
 src/lib3270/host.c    | 29 +++++++++++++++++++++++++++--
 3 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/src/include/lib3270.h b/src/include/lib3270.h
index 0f245b0..d706deb 100644
--- a/src/include/lib3270.h
+++ b/src/include/lib3270.h
@@ -473,7 +473,7 @@
 	 * @return 0 if suceeds, non zero if fails (sets errno).
 	 *
 	 */
-	LIB3270_EXPORT int lib3270_unregister_schange(H3270 *hSession, LIB3270_STATE tx, void * id);
+	LIB3270_EXPORT int lib3270_unregister_schange(H3270 *hSession, LIB3270_STATE tx, const void * id);
 
 	LIB3270_EXPORT void lib3270_reset_callbacks(H3270 *hSession);
 
diff --git a/src/lib3270/connect.c b/src/lib3270/connect.c
index f827352..6cbb375 100644
--- a/src/lib3270/connect.c
+++ b/src/lib3270/connect.c
@@ -50,6 +50,8 @@
 
  int lib3270_reconnect(H3270 *hSession, int seconds)
  {
+ 	debug("%s",__FUNCTION__);
+
  	FAIL_IF_ONLINE(hSession);
 
 	//
diff --git a/src/lib3270/host.c b/src/lib3270/host.c
index c834051..35e7bff 100644
--- a/src/lib3270/host.c
+++ b/src/lib3270/host.c
@@ -197,11 +197,22 @@ LIB3270_EXPORT const void * lib3270_register_schange(H3270 *hSession, LIB3270_ST
 
 }
 
-LIB3270_EXPORT int lib3270_unregister_schange(H3270 *hSession, LIB3270_STATE tx, void * id)
+LIB3270_EXPORT int lib3270_unregister_schange(H3270 *hSession, LIB3270_STATE tx, const void * id)
 {
 	struct lib3270_state_callback *st;
 	struct lib3270_state_callback *prev = (struct lib3270_state_callback *) NULL;
 
+#ifdef DEBUG
+	{
+		debug("Before remove of %p (last=%p):",id,hSession->st.last[tx]);
+
+		for (st = hSession->st.callbacks[tx]; st != (struct lib3270_state_callback *) NULL; st = (struct lib3270_state_callback *) st->next)
+		{
+			debug("%p",st);
+		}
+	}
+#endif // DEBUG
+
 	for (st = hSession->st.callbacks[tx]; st != (struct lib3270_state_callback *) NULL; st = (struct lib3270_state_callback *) st->next)
 	{
 		if (st == (struct lib3270_state_callback *)id)
@@ -221,7 +232,21 @@ LIB3270_EXPORT int lib3270_unregister_schange(H3270 *hSession, LIB3270_STATE tx,
 	else
 		hSession->st.callbacks[tx] = (struct lib3270_state_callback *) st->next;
 
-	lib3270_free(id);
+	for(st = hSession->st.callbacks[tx]; st != (struct lib3270_state_callback *) NULL; st = (struct lib3270_state_callback *) st->next)
+		hSession->st.last[tx] = st;
+
+	lib3270_free((void *) id);
+
+#ifdef DEBUG
+	{
+		debug("After Remove of %p (last=%p):",id,hSession->st.last[tx]);
+
+		for (st = hSession->st.callbacks[tx]; st != (struct lib3270_state_callback *) NULL; st = (struct lib3270_state_callback *) st->next)
+		{
+			debug("%p",st);
+		}
+	}
+#endif // DEBUG
 
 	return 0;
 }
--
libgit2 0.21.2