1/* Copyright (C) 1992, 1995, 1996, 1997, 2002, 2011 Free Software Foundation,
2   Inc.
3   This file based on setenv.c in the GNU C Library.
4
5   The GNU C Library is free software; you can redistribute it and/or
6   modify it under the terms of the GNU Library General Public License as
7   published by the Free Software Foundation; either version 2 of the
8   License, or (at your option) any later version.
9
10   The GNU C Library is distributed in the hope that it will be useful,
11   but WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13   Library General Public License for more details.
14
15   You should have received a copy of the GNU Library General Public
16   License along with the GNU C Library; see the file COPYING.LIB.  If not,
17   write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
18   Boston, MA 02110-1301, USA.  */
19
20
21/*
22
23@deftypefn Supplemental int setenv (const char *@var{name}, @
24  const char *@var{value}, int @var{overwrite})
25@deftypefnx Supplemental void unsetenv (const char *@var{name})
26
27@code{setenv} adds @var{name} to the environment with value
28@var{value}.  If the name was already present in the environment,
29the new value will be stored only if @var{overwrite} is nonzero.
30The companion @code{unsetenv} function removes @var{name} from the
31environment.  This implementation is not safe for multithreaded code.
32
33@end deftypefn
34
35*/
36
37#if HAVE_CONFIG_H
38# include <config.h>
39#endif
40
41#define setenv libiberty_setenv
42#define unsetenv libiberty_unsetenv
43
44#include "ansidecl.h"
45#include <sys/types.h> /* For `size_t' */
46#include <stdio.h>     /* For `NULL' */
47
48#include <errno.h>
49#if !defined(errno) && !defined(HAVE_ERRNO_DECL)
50extern int errno;
51#endif
52#define __set_errno(ev) ((errno) = (ev))
53
54#if HAVE_STDLIB_H
55# include <stdlib.h>
56#endif
57#if HAVE_STRING_H
58# include <string.h>
59#endif
60#if HAVE_UNISTD_H
61# include <unistd.h>
62#endif
63
64#define __environ	environ
65#ifndef HAVE_ENVIRON_DECL
66extern char **environ;
67#endif
68
69#undef setenv
70#undef unsetenv
71
72/* LOCK and UNLOCK are defined as no-ops.  This makes the libiberty
73 * implementation MT-Unsafe. */
74#define LOCK
75#define UNLOCK
76
77/* Below this point, it's verbatim code from the glibc-2.0 implementation */
78
79/* If this variable is not a null pointer we allocated the current
80   environment.  */
81static char **last_environ;
82
83
84int
85setenv (const char *name, const char *value, int replace)
86{
87  register char **ep = 0;
88  register size_t size;
89  const size_t namelen = strlen (name);
90  const size_t vallen = strlen (value) + 1;
91
92  LOCK;
93
94  size = 0;
95  if (__environ != NULL)
96    {
97      for (ep = __environ; *ep != NULL; ++ep)
98	if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
99	  break;
100	else
101	  ++size;
102    }
103
104  if (__environ == NULL || *ep == NULL)
105    {
106      char **new_environ;
107      if (__environ == last_environ && __environ != NULL)
108	/* We allocated this space; we can extend it.  */
109	new_environ = (char **) realloc (last_environ,
110					 (size + 2) * sizeof (char *));
111      else
112	new_environ = (char **) malloc ((size + 2) * sizeof (char *));
113
114      if (new_environ == NULL)
115	{
116	  UNLOCK;
117	  return -1;
118	}
119
120      new_environ[size] = (char *) malloc (namelen + 1 + vallen);
121      if (new_environ[size] == NULL)
122	{
123	  free ((char *) new_environ);
124	  __set_errno (ENOMEM);
125	  UNLOCK;
126	  return -1;
127	}
128
129      if (__environ != last_environ)
130	memcpy ((char *) new_environ, (char *) __environ,
131		size * sizeof (char *));
132
133      memcpy (new_environ[size], name, namelen);
134      new_environ[size][namelen] = '=';
135      memcpy (&new_environ[size][namelen + 1], value, vallen);
136
137      new_environ[size + 1] = NULL;
138
139      last_environ = __environ = new_environ;
140    }
141  else if (replace)
142    {
143      size_t len = strlen (*ep);
144      if (len + 1 < namelen + 1 + vallen)
145	{
146	  /* The existing string is too short; malloc a new one.  */
147	  char *new_string = (char *) malloc (namelen + 1 + vallen);
148	  if (new_string == NULL)
149	    {
150	      UNLOCK;
151	      return -1;
152	    }
153	  *ep = new_string;
154	}
155      memcpy (*ep, name, namelen);
156      (*ep)[namelen] = '=';
157      memcpy (&(*ep)[namelen + 1], value, vallen);
158    }
159
160  UNLOCK;
161
162  return 0;
163}
164
165void
166unsetenv (const char *name)
167{
168  const size_t len = strlen (name);
169  char **ep;
170
171  LOCK;
172
173  for (ep = __environ; *ep; ++ep)
174    if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
175      {
176	/* Found it.  Remove this pointer by moving later ones back.  */
177	char **dp = ep;
178	do
179	  dp[0] = dp[1];
180	while (*dp++);
181	/* Continue the loop in case NAME appears again.  */
182      }
183
184  UNLOCK;
185}
186