From 6012ec9e56a8b3c41193652c58285699733cbf59 Mon Sep 17 00:00:00 2001
From: aquanight <aquanight@gmail.com>
Date: Sun, 5 Jul 2020 15:31:07 -0600
Subject: [PATCH] Prevent double calls of perl_script_unload

---
 src/perl/perl-core.c    | 28 ++++++++++++++++++++++++----
 src/perl/perl-core.h    |  7 +++++++
 src/perl/perl-fe.c      |  2 +-
 src/perl/perl-signals.c |  4 ++++
 src/perl/perl-sources.c |  5 +++++
 5 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/src/perl/perl-core.c b/src/perl/perl-core.c
index 866b86e8..295715d3 100644
--- a/src/perl/perl-core.c
+++ b/src/perl/perl-core.c
@@ -67,9 +67,6 @@ static void perl_script_destroy(PERL_SCRIPT_REC *script)
 {
 	perl_scripts = g_slist_remove(perl_scripts, script);
 
-	perl_signal_remove_script(script);
-	perl_source_remove_script(script);
-
 	signal_emit("script destroyed", 1, script);
 
 	g_free(script->name);
@@ -314,7 +311,30 @@ void perl_script_unload(PERL_SCRIPT_REC *script)
         g_return_if_fail(script != NULL);
 
 	perl_script_destroy_package(script);
-        perl_script_destroy(script);
+
+	perl_signal_remove_script(script);
+	perl_source_remove_script(script);
+
+	script->unloaded = 1;
+	if (!script->active_signals)
+	        perl_script_destroy(script);
+}
+
+/* Enter a perl script (signal or input source) */
+void perl_script_enter(PERL_SCRIPT_REC *script)
+{
+	g_return_if_fail(script != NULL);
+
+	script->active_signals++;
+}
+
+void perl_script_exit(PERL_SCRIPT_REC *script)
+{
+	g_return_if_fail(script != NULL);
+
+	script->active_signals--;
+	if (script->unloaded)
+		perl_script_destroy(script);
 }
 
 /* Find loaded script by name */
diff --git a/src/perl/perl-core.h b/src/perl/perl-core.h
index 0d3a1a2f..5b2de9ac 100644
--- a/src/perl/perl-core.h
+++ b/src/perl/perl-core.h
@@ -8,6 +8,8 @@ typedef struct {
         /* Script can be loaded from a file, or from some data in memory */
 	char *path; /* FILE: full path for file */
 	char *data; /* DATA: data used for the script */
+	int unloaded; /* Indicates unloading has been done, so it should be destroyed once all signals exit */
+	int active_signals; /* active signal calls into this script - prevents full teardown when nonzero */
 } PERL_SCRIPT_REC;
 
 extern GSList *perl_scripts;
@@ -26,6 +28,11 @@ PERL_SCRIPT_REC *perl_script_load_data(const char *data);
 /* Unload perl script */
 void perl_script_unload(PERL_SCRIPT_REC *script);
 
+/* Mark a script as entered */
+void perl_script_enter(PERL_SCRIPT_REC *script);
+/* Mark a script as exited */
+void perl_script_exit(PERL_SCRIPT_REC *script);
+
 /* Find loaded script by name */
 PERL_SCRIPT_REC *perl_script_find(const char *name);
 /* Find loaded script by package */
diff --git a/src/perl/perl-fe.c b/src/perl/perl-fe.c
index ac84d67a..ba6dccce 100644
--- a/src/perl/perl-fe.c
+++ b/src/perl/perl-fe.c
@@ -106,7 +106,7 @@ static void cmd_script_unload(const char *data)
 
         script_fix_name(name);
 	script = perl_script_find(name);
-	if (script == NULL) {
+	if (script == NULL || script->unloaded) {
 		printformat(NULL, NULL, MSGLEVEL_CLIENTERROR,
                             TXT_SCRIPT_NOT_LOADED, name);
 	} else {
diff --git a/src/perl/perl-signals.c b/src/perl/perl-signals.c
index 27522f5e..5ea40d73 100644
--- a/src/perl/perl-signals.c
+++ b/src/perl/perl-signals.c
@@ -420,7 +420,10 @@ static void sig_func(const void *p1, const void *p2,
 	args[3] = p4; args[4] = p5; args[5] = p6;
 
 	rec = signal_get_user_data();
+	if (rec->script->unloaded) return; /* Drop signal calls into unloaded scripts. */
+	perl_script_enter(rec->script);
 	perl_call_signal(rec->script, rec->func, signal_get_emitted_id(), args);
+	perl_script_exit(rec->script);
 }
 
 static void perl_signal_add_full_int(const char *signal, SV *func,
@@ -437,6 +440,7 @@ static void perl_signal_add_full_int(const char *signal, SV *func,
 
         script = perl_script_find_package(perl_get_package());
         g_return_if_fail(script != NULL);
+	g_return_if_fail(script->unloaded);
 
 	rec = g_new(PERL_SIGNAL_REC, 1);
         rec->script = script;
diff --git a/src/perl/perl-sources.c b/src/perl/perl-sources.c
index 3c72be22..57fb579d 100644
--- a/src/perl/perl-sources.c
+++ b/src/perl/perl-sources.c
@@ -78,6 +78,7 @@ static int perl_source_event(PERL_SOURCE_REC *rec)
 	PUTBACK;
 
         perl_source_ref(rec);
+	perl_script_enter(rec->script);
 	perl_call_sv(rec->func, G_EVAL|G_DISCARD);
 
 	if (SvTRUE(ERRSV)) {
@@ -86,6 +87,8 @@ static int perl_source_event(PERL_SOURCE_REC *rec)
                 g_free(error);
 	}
 
+	perl_script_exit(rec->script);
+
 	if (perl_source_unref(rec) && rec->once)
 		perl_source_destroy(rec);
 
@@ -104,6 +107,7 @@ int perl_timeout_add(int msecs, SV *func, SV *data, int once)
         pkg = perl_get_package();
 	script = perl_script_find_package(pkg);
         g_return_val_if_fail(script != NULL, -1);
+	g_return_val_if_fail(script->unloaded, -1);
 
 	rec = g_new0(PERL_SOURCE_REC, 1);
 	perl_source_ref(rec);
@@ -127,6 +131,7 @@ int perl_input_add(int source, int condition, SV *func, SV *data, int once)
         pkg = perl_get_package();
 	script = perl_script_find_package(pkg);
         g_return_val_if_fail(script != NULL, -1);
+	g_return_val_if_fail(script->unloaded, -1);
 
 	rec = g_new0(PERL_SOURCE_REC, 1);
 	perl_source_ref(rec);