setenv.c revision 60484 
1/* Copyright (C) 1992, 1995, 1996, 1997 Free Software Foundation, Inc.
2   This file based on setenv.c in the GNU C Library.
3
4   The GNU C Library is free software; you can redistribute it and/or
5   modify it under the terms of the GNU Library General Public License as
6   published by the Free Software Foundation; either version 2 of the
7   License, or (at your option) any later version.
8
9   The GNU C Library is distributed in the hope that it will be useful,
10   but WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12   Library General Public License for more details.
13
14   You should have received a copy of the GNU Library General Public
15   License along with the GNU C Library; see the file COPYING.LIB.  If not,
16   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17   Boston, MA 02111-1307, USA.  */
18
19#if HAVE_CONFIG_H
20# include <config.h>
21#endif
22
23#include "ansidecl.h"
24#include <sys/types.h> /* For `size_t' */
25#include <stdio.h>     /* For `NULL' */
26
27#include <errno.h>
28#if !defined(errno) && !defined(HAVE_ERRNO_DECL)
29extern int errno;
30#endif
31#define __set_errno(ev) ((errno) = (ev))
32
33#if HAVE_STDLIB_H
34# include <stdlib.h>
35#endif
36#if HAVE_STRING_H
37# include <string.h>
38#endif
39#if HAVE_UNISTD_H
40# include <unistd.h>
41#endif
42
43#define __environ	environ
44#ifndef HAVE_ENVIRON_DECL
45extern char **environ;
46#endif
47
48/* LOCK and UNLOCK are defined as no-ops.  This makes the libiberty
49 * implementation MT-Unsafe. */
50#define LOCK
51#define UNLOCK
52
53/* Below this point, it's verbatim code from the glibc-2.0 implementation */
54
55/* If this variable is not a null pointer we allocated the current
56   environment.  */
57static char **last_environ;
58
59
60int
61setenv (name, value, replace)
62     const char *name;
63     const char *value;
64     int replace;
65{
66  register char **ep;
67  register size_t size;
68  const size_t namelen = strlen (name);
69  const size_t vallen = strlen (value) + 1;
70
71  LOCK;
72
73  size = 0;
74  if (__environ != NULL)
75    for (ep = __environ; *ep != NULL; ++ep)
76      if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
77	break;
78      else
79	++size;
80
81  if (__environ == NULL || *ep == NULL)
82    {
83      char **new_environ;
84      if (__environ == last_environ && __environ != NULL)
85	/* We allocated this space; we can extend it.  */
86	new_environ = (char **) realloc (last_environ,
87					 (size + 2) * sizeof (char *));
88      else
89	new_environ = (char **) malloc ((size + 2) * sizeof (char *));
90
91      if (new_environ == NULL)
92	{
93	  UNLOCK;
94	  return -1;
95	}
96
97      new_environ[size] = malloc (namelen + 1 + vallen);
98      if (new_environ[size] == NULL)
99	{
100	  free ((char *) new_environ);
101	  __set_errno (ENOMEM);
102	  UNLOCK;
103	  return -1;
104	}
105
106      if (__environ != last_environ)
107	memcpy ((char *) new_environ, (char *) __environ,
108		size * sizeof (char *));
109
110      memcpy (new_environ[size], name, namelen);
111      new_environ[size][namelen] = '=';
112      memcpy (&new_environ[size][namelen + 1], value, vallen);
113
114      new_environ[size + 1] = NULL;
115
116      last_environ = __environ = new_environ;
117    }
118  else if (replace)
119    {
120      size_t len = strlen (*ep);
121      if (len + 1 < namelen + 1 + vallen)
122	{
123	  /* The existing string is too short; malloc a new one.  */
124	  char *new = malloc (namelen + 1 + vallen);
125	  if (new == NULL)
126	    {
127	      UNLOCK;
128	      return -1;
129	    }
130	  *ep = new;
131	}
132      memcpy (*ep, name, namelen);
133      (*ep)[namelen] = '=';
134      memcpy (&(*ep)[namelen + 1], value, vallen);
135    }
136
137  UNLOCK;
138
139  return 0;
140}
141
142void
143unsetenv (name)
144     const char *name;
145{
146  const size_t len = strlen (name);
147  char **ep;
148
149  LOCK;
150
151  for (ep = __environ; *ep; ++ep)
152    if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
153      {
154	/* Found it.  Remove this pointer by moving later ones back.  */
155	char **dp = ep;
156	do
157	  dp[0] = dp[1];
158	while (*dp++);
159	/* Continue the loop in case NAME appears again.  */
160      }
161
162  UNLOCK;
163}
164