runtime: allowing for repeated calls to caml_startup and caml_shutdown

4 files changed, 47 insertions, 3 deletions

diff --git a/asmrun/startup.c b/asmrun/startup.c
index 834e6cdda3..7abec8d11b 100644
--- a/asmrun/startup.c
+++ b/asmrun/startup.c
@@ -105,7 +105,8 @@ value caml_startup_exn(char **argv)
   char * exe_name, * proc_self_exe;
   char tos;
 
-  caml_stat_create_pool();
+  if (!caml_startup_aux())
+    return Val_unit;
 
 #ifdef WITH_SPACETIME
   caml_spacetime_initialize();
diff --git a/byterun/caml/startup_aux.h b/byterun/caml/startup_aux.h
index 203a47d73d..80ff2e0926 100644
--- a/byterun/caml/startup_aux.h
+++ b/byterun/caml/startup_aux.h
@@ -33,6 +33,10 @@ extern uintnat caml_trace_level;
 
 extern void caml_parse_ocamlrunparam (void);
 
+/* Common entry point to caml_startup.
+   Returns 0 if the runtime is already initialized. */
+extern int caml_startup_aux (void);
+
 #endif /* CAML_INTERNALS */
 
 #endif /* CAML_STARTUP_AUX_H */
diff --git a/byterun/startup.c b/byterun/startup.c
index 705456492b..04032f0221 100644
--- a/byterun/startup.c
+++ b/byterun/startup.c
@@ -286,7 +286,8 @@ CAMLexport void caml_main(char **argv)
 
   caml_ensure_spacetime_dot_o_is_included++;
 
-  caml_stat_create_pool();
+  if (!caml_startup_aux())
+    return;
 
   /* Machine-dependent initialization of the floating-point hardware
      so that it behaves as much as possible as specified in IEEE */
@@ -407,7 +408,9 @@ CAMLexport value caml_startup_code_exn(
   char * cds_file;
   char * exe_name;
 
-  caml_stat_create_pool();
+  if (!caml_startup_aux())
+    return Val_unit;
+
   caml_init_ieee_floats();
 #if defined(_MSC_VER) && __STDC_SECURE_LIB__ >= 200411L
   caml_install_invalid_parameter_handler();
diff --git a/byterun/startup_aux.c b/byterun/startup_aux.c
index 63bf7f65de..21403e3288 100644
--- a/byterun/startup_aux.c
+++ b/byterun/startup_aux.c
@@ -108,11 +108,47 @@ void caml_parse_ocamlrunparam(void)
   }
 }
 
+
+/* The number of outstanding calls to caml_startup */
+static int startup_count = 0;
+
+/* Has the runtime been shut down already? */
+static int shutdown_happened = 0;
+
+
+int caml_startup_aux(void)
+{
+  if (shutdown_happened == 1)
+    caml_fatal_error("Fatal error: caml_startup was called after the runtime "
+                     "was shut down with caml_shutdown");
+
+  /* Second and subsequent calls are ignored,
+     since the runtime has already started */
+  startup_count++;
+  if (startup_count > 1)
+    return 0;
+
+  caml_stat_create_pool();
+
+  return 1;
+}
+
 CAMLexport void caml_shutdown(void)
 {
+  if (startup_count <= 0)
+    caml_fatal_error("Fatal error: a call to caml_shutdown has no "
+                     "corresponding call to caml_startup");
+
+  /* Do nothing unless it's the last call remaining */
+  startup_count--;
+  if (startup_count > 0)
+    return;
+
   caml_finalise_heap();
 #ifndef NATIVE_CODE
   caml_free_shared_libs();
 #endif
   caml_stat_destroy_pool();
+
+  shutdown_happened = 1;
 }