go-unsetenv.c
1.12 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
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);
}