1 files changed, 31 insertions, 0 deletions
diff --git a/libc-bottom-half/sources/environ.c b/libc-bottom-half/sources/environ.c
new file mode 100644
index 0000000..50d60de
--- /dev/null
+++ b/libc-bottom-half/sources/environ.c
@@ -0,0 +1,31 @@
+#include <unistd.h>
+#include <stdlib.h>
+#include <sysexits.h>
+#include <wasi/api.h>
+#include <wasi/libc.h>
+#include <wasi/libc-environ.h>
+
+// If the program does use `environ`, it'll get this version of
+// `__wasilibc_environ`, which is initialized with a constructor function, so
+// that it's initialized whenever user code might want to access it.
+char **__wasilibc_environ;
+weak_alias(__wasilibc_environ, _environ);
+weak_alias(__wasilibc_environ, environ);
+
+// We define this function here in the same source file as
+// `__wasilibc_environ`, so that this function is called in iff environment
+// variable support is used.
+// Concerning the 50 -- levels up to 100 are reserved for the implementation,
+// so we an arbitrary number in the middle of the range to allow other
+// reserved things to go before or after.
+__attribute__((constructor(50)))
+static void __wasilibc_initialize_environ_eagerly(void) {
+    __wasilibc_initialize_environ();
+}
+
+// See the comments in libc-environ.h.
+void __wasilibc_maybe_reinitialize_environ_eagerly(void) {
+    // This translation unit is linked in if `environ` is used, meaning we need
+    // to eagerly reinitialize the environment variables.
+    __wasilibc_initialize_environ();
+}