aboutsummaryrefslogtreecommitdiff
path: root/libiberty/setenv.c
blob: 714ca0a407687e9be46c3da4427f974186a2b9f1 (plain)
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
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
/* Copyright (C) 1992, 1995, 1996, 1997, 2002, 2011 Free Software Foundation,
   Inc.
   This file based on setenv.c in the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
   Boston, MA 02110-1301, USA.  */


/*

@deftypefn Supplemental int setenv (const char *@var{name}, @
  const char *@var{value}, int @var{overwrite})
@deftypefnx Supplemental void unsetenv (const char *@var{name})

@code{setenv} adds @var{name} to the environment with value
@var{value}.  If the name was already present in the environment,
the new value will be stored only if @var{overwrite} is nonzero.
The companion @code{unsetenv} function removes @var{name} from the
environment.  This implementation is not safe for multithreaded code.

@end deftypefn

*/

#if HAVE_CONFIG_H
# include <config.h>
#endif

#define setenv libiberty_setenv
#define unsetenv libiberty_unsetenv

#include "ansidecl.h"
#include <sys/types.h> /* For `size_t' */
#include <stdio.h>     /* For `NULL' */

#include <errno.h>
#if !defined(errno) && !defined(HAVE_ERRNO_DECL)
extern int errno;
#endif
#define __set_errno(ev) ((errno) = (ev))

#if HAVE_STDLIB_H
# include <stdlib.h>
#endif
#if HAVE_STRING_H
# include <string.h>
#endif
#if HAVE_UNISTD_H
# include <unistd.h>
#endif

#define __environ	environ
#ifndef HAVE_ENVIRON_DECL
#ifndef environ
extern char **environ;
#endif
#endif

#undef setenv
#undef unsetenv

/* LOCK and UNLOCK are defined as no-ops.  This makes the libiberty
 * implementation MT-Unsafe. */
#define LOCK
#define UNLOCK

/* Below this point, it's verbatim code from the glibc-2.0 implementation */

/* If this variable is not a null pointer we allocated the current
   environment.  */
static char **last_environ;


int
setenv (const char *name, const char *value, int replace)
{
  register char **ep = 0;
  register size_t size;
  const size_t namelen = strlen (name);
  const size_t vallen = strlen (value) + 1;

  LOCK;

  size = 0;
  if (__environ != NULL)
    {
      for (ep = __environ; *ep != NULL; ++ep)
	if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
	  break;
	else
	  ++size;
    }

  if (__environ == NULL || *ep == NULL)
    {
      char **new_environ;
      if (__environ == last_environ && __environ != NULL)
	/* We allocated this space; we can extend it.  */
	new_environ = (char **) realloc (last_environ,
					 (size + 2) * sizeof (char *));
      else
	new_environ = (char **) malloc ((size + 2) * sizeof (char *));

      if (new_environ == NULL)
	{
	  UNLOCK;
	  return -1;
	}

      new_environ[size] = (char *) malloc (namelen + 1 + vallen);
      if (new_environ[size] == NULL)
	{
	  free ((char *) new_environ);
	  __set_errno (ENOMEM);
	  UNLOCK;
	  return -1;
	}

      if (__environ != last_environ)
	memcpy ((char *) new_environ, (char *) __environ,
		size * sizeof (char *));

      memcpy (new_environ[size], name, namelen);
      new_environ[size][namelen] = '=';
      memcpy (&new_environ[size][namelen + 1], value, vallen);

      new_environ[size + 1] = NULL;

      last_environ = __environ = new_environ;
    }
  else if (replace)
    {
      size_t len = strlen (*ep);
      if (len + 1 < namelen + 1 + vallen)
	{
	  /* The existing string is too short; malloc a new one.  */
	  char *new_string = (char *) malloc (namelen + 1 + vallen);
	  if (new_string == NULL)
	    {
	      UNLOCK;
	      return -1;
	    }
	  *ep = new_string;
	}
      memcpy (*ep, name, namelen);
      (*ep)[namelen] = '=';
      memcpy (&(*ep)[namelen + 1], value, vallen);
    }

  UNLOCK;

  return 0;
}

void
unsetenv (const char *name)
{
  const size_t len = strlen (name);
  char **ep;

  LOCK;

  for (ep = __environ; *ep; ++ep)
    if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
      {
	/* Found it.  Remove this pointer by moving later ones back.  */
	char **dp = ep;
	do
	  dp[0] = dp[1];
	while (*dp++);
	/* Continue the loop in case NAME appears again.  */
      }

  UNLOCK;
}