libgo/runtime/go-setenv.c

   1 /* go-setenv.c -- set the C environment from Go.
   2
   3    Copyright 2011 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 "go-alloc.h"
  13 #include "runtime.h"
  14 #include "arch.h"
  15 #include "malloc.h"
  16
  17 /* Set the C environment from Go.  This is called by syscall.Setenv.  */
  18
  19 void setenv_c (String, String) __asm__ (GOSYM_PREFIX "syscall.setenv_c");
  20
  21 void
  22 setenv_c (String k, String v)
  23 {
  24   const byte *ks;
  25   unsigned char *kn;
  26   const byte *vs;
  27   unsigned char *vn;
  28   intgo len;
  29
  30   ks = k.str;
  31   if (ks == NULL)
  32     ks = (const byte *) "";
  33   kn = NULL;
  34
  35   vs = v.str;
  36   if (vs == NULL)
  37     vs = (const byte *) "";
  38   vn = NULL;
  39
  40 #ifdef HAVE_SETENV
  41
  42   if (ks != NULL && ks[k.len] != 0)
  43     {
  44       // Objects that are explicitly freed must be at least 16 bytes in size,
  45       // so that they are not allocated using tiny alloc.
  46       len = k.len + 1;
  47       if (len < TinySize)
  48         len = TinySize;
  49       kn = __go_alloc (len);
  50       __builtin_memcpy (kn, ks, k.len);
  51       ks = kn;
  52     }
  53
  54   if (vs != NULL && vs[v.len] != 0)
  55     {
  56       len = v.len + 1;
  57       if (len < TinySize)
  58         len = TinySize;
  59       vn = __go_alloc (len);
  60       __builtin_memcpy (vn, vs, v.len);
  61       vs = vn;
  62     }
  63
  64   setenv ((const char *) ks, (const char *) vs, 1);
  65
  66 #else /* !defined(HAVE_SETENV) */
  67
  68   len = k.len + v.len + 2;
  69   if (len < TinySize)
  70     len = TinySize;
  71   kn = __go_alloc (len);
  72   __builtin_memcpy (kn, ks, k.len);
  73   kn[k.len] = '=';
  74   __builtin_memcpy (kn + k.len + 1, vs, v.len);
  75   kn[k.len + v.len + 1] = '\0';
  76   putenv ((char *) kn);
  77
  78 #endif /* !defined(HAVE_SETENV) */
  79
  80   if (kn != NULL)
  81     __go_free (kn);
  82   if (vn != NULL)
  83     __go_free (vn);
  84 }