libgo/runtime/go-unsetenv.c

   1 /* go-unsetenv.c -- unset an environment variable from Go.
   2
   3    Copyright 2015 The Go Authors. All rights reserved.
   4    Use of this source code is governed by a BSD-style
   5    license that can be found in the LICENSE file.  */
   6
   7 #include "config.h"
   8
   9 #include <stddef.h>
  10 #include <stdlib.h>
  11
  12 #include "runtime.h"
  13
  14 /* Unset an environment variable from Go.  This is called by
  15    syscall.Unsetenv.  */
  16
  17 void unsetenv_c (String) __asm__ (GOSYM_PREFIX "syscall.unsetenv_c");
  18
  19 void
  20 unsetenv_c (String k)
  21 {
  22   const byte *ks;
  23   unsigned char *kn;
  24
  25   ks = k.str;
  26   if (ks == NULL)
  27     ks = (const byte *) "";
  28   kn = NULL;
  29
  30 #ifdef HAVE_UNSETENV
  31
  32   if (ks[k.len] != 0)
  33     {
  34       kn = malloc (k.len + 1);
  35       if (kn == NULL)
  36         runtime_throw ("out of malloc memory");
  37       __builtin_memcpy (kn, ks, k.len);
  38       ks = kn;
  39     }
  40
  41   unsetenv ((const char *) ks);
  42
  43 #endif /* !defined(HAVE_UNSETENV) */
  44
  45   if (kn != NULL)
  46     free (kn);
  47 }