core: Use a global lock instead of runtime lock for os::getenv, etc. #4726

src/rt/rust_env.cpp

@@ -13,6 +13,7 @@
 // that might come from the environment is loaded here, once, during
 // init.
 
+#include "sync/lock_and_signal.h"
 #include "rust_env.h"
 
 // The environment variables that the runtime knows about
@@ -26,6 +27,18 @@
 #define RUST_DEBUG_MEM "RUST_DEBUG_MEM"
 #define RUST_DEBUG_BORROW "RUST_DEBUG_BORROW"
 
+static lock_and_signal env_lock;
+
+extern "C" CDECL void
+rust_take_env_lock() {
+    env_lock.lock();
+}
+
+extern "C" CDECL void
+rust_drop_env_lock() {
+    env_lock.unlock();
+}
+
 #if defined(__WIN32__)
 static int
 get_num_cpus() {
@@ -119,6 +132,8 @@ copyenv(const char* name) {
 
 rust_env*
 load_env(int argc, char **argv) {
+    scoped_lock with(env_lock);
+
     rust_env *env = (rust_env*)malloc(sizeof(rust_env));
 
     env->num_sched_threads = (size_t)get_num_threads();
@@ -141,3 +156,4 @@ free_env(rust_env *env) {
     free(env->rust_seed);
     free(env);
 }
+