1 /* Copyright (C) 1991, 1994, 1997-1998, 2000, 2003-2013 Free Software
4 NOTE: The canonical source of this file is maintained with the GNU C
5 Library. Bugs can be reported to bug-glibc@prep.ai.mit.edu.
7 This program is free software: you can redistribute it and/or modify it
8 under the terms of the GNU Lesser General Public License as published by the
9 Free Software Foundation; either version 3 of the License, or any
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU Lesser General Public License for more details.
17 You should have received a copy of the GNU Lesser General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
27 /* Include errno.h *after* sys/types.h to work around header problems
31 # define __set_errno(ev) ((errno) = (ev))
39 # define environ __environ
41 extern char **environ
;
46 /* This lock protects against simultaneous modifications of 'environ'. */
47 # include <bits/libc-lock.h>
48 __libc_lock_define_initialized (static, envlock
)
49 # define LOCK __libc_lock_lock (envlock)
50 # define UNLOCK __libc_lock_unlock (envlock)
57 _unsetenv (const char *name
)
62 if (name
== NULL
|| *name
== '\0' || strchr (name
, '=') != NULL
)
74 if (!strncmp (*ep
, name
, len
) && (*ep
)[len
] == '=')
76 /* Found it. Remove this pointer by moving later ones back. */
82 /* Continue the loop in case NAME appears again. */
93 /* Put STRING, which is of the form "NAME=VALUE", in the environment.
94 If STRING contains no '=', then remove STRING from the environment. */
98 const char *const name_end
= strchr (string
, '=');
102 if (name_end
== NULL
)
104 /* Remove the variable from the environment. */
105 return _unsetenv (string
);
109 for (ep
= environ
; *ep
!= NULL
; ++ep
)
110 if (!strncmp (*ep
, string
, name_end
- string
) &&
111 (*ep
)[name_end
- string
] == '=')
119 /* Rely on _putenv to allocate the new environment. If other
120 parts of the application use _putenv, the !HAVE__PUTENV code
121 would fight over who owns the environ vector, causing a crash. */
123 return _putenv (string
);
126 /* _putenv ("NAME=") unsets NAME, so invoke _putenv ("NAME=x")
127 to allocate the environ vector and then replace the new
128 entry with "NAME=". */
129 int putenv_result
, putenv_errno
;
130 char *name_x
= malloc (name_end
- string
+ sizeof "=x");
133 memcpy (name_x
, string
, name_end
- string
+ 1);
134 name_x
[name_end
- string
+ 1] = 'x';
135 name_x
[name_end
- string
+ 2] = 0;
136 putenv_result
= _putenv (name_x
);
137 putenv_errno
= errno
;
138 for (ep
= environ
; *ep
; ep
++)
145 __set_errno (putenv_errno
);
146 return putenv_result
;
149 static char **last_environ
= NULL
;
150 char **new_environ
= (char **) malloc ((size
+ 2) * sizeof (char *));
151 if (new_environ
== NULL
)
153 (void) memcpy ((void *) new_environ
, (void *) environ
,
154 size
* sizeof (char *));
155 new_environ
[size
] = (char *) string
;
156 new_environ
[size
+ 1] = NULL
;
158 last_environ
= new_environ
;
159 environ
= new_environ
;