1 files changed, 54 insertions, 0 deletions
diff --git a/llgo/third_party/gofrontend/libgo/runtime/go-unsetenv.c b/llgo/third_party/gofrontend/libgo/runtime/go-unsetenv.c
new file mode 100644
index 00000000000..409436a0d3f
--- /dev/null
+++ b/llgo/third_party/gofrontend/libgo/runtime/go-unsetenv.c
@@ -0,0 +1,54 @@
+/* go-unsetenv.c -- unset an environment variable from Go.
+
+   Copyright 2015 The Go Authors. All rights reserved.
+   Use of this source code is governed by a BSD-style
+   license that can be found in the LICENSE file.  */
+
+#include "config.h"
+
+#include <stddef.h>
+#include <stdlib.h>
+
+#include "go-alloc.h"
+#include "runtime.h"
+#include "arch.h"
+#include "malloc.h"
+
+/* Unset an environment variable from Go.  This is called by
+   syscall.Unsetenv.  */
+
+void unsetenv_c (String) __asm__ (GOSYM_PREFIX "syscall.unsetenv_c");
+
+void
+unsetenv_c (String k)
+{
+  const byte *ks;
+  unsigned char *kn;
+  intgo len;
+
+  ks = k.str;
+  if (ks == NULL)
+    ks = (const byte *) "";
+  kn = NULL;
+
+#ifdef HAVE_UNSETENV
+
+  if (ks != NULL && ks[k.len] != 0)
+    {
+      // Objects that are explicitly freed must be at least 16 bytes in size,
+      // so that they are not allocated using tiny alloc.
+      len = k.len + 1;
+      if (len < TinySize)
+	len = TinySize;
+      kn = __go_alloc (len);
+      __builtin_memcpy (kn, ks, k.len);
+      ks = kn;
+    }
+
+  unsetenv ((const char *) ks);
+
+#endif /* !defined(HAVE_UNSETENV) */
+
+  if (kn != NULL)
+    __go_free (kn);
+}