1 /* Copyright (C) 1992,1995-1999,2000-2003,2005-2007 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3 of the License, or
7 (at your option) any later version.
9 This program 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
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 # define __set_errno(ev) ((errno) = (ev))
29 #if _LIBC || HAVE_UNISTD_H
33 #if _LIBC || !HAVE_SETENV
40 # define __environ environ
41 # ifndef HAVE_ENVIRON_DECL
42 extern char **environ;
47 /* This lock protects against simultaneous modifications of `environ'. */
48 # include <bits/libc-lock.h>
49 __libc_lock_define_initialized (static, envlock)
50 # define LOCK __libc_lock_lock (envlock)
51 # define UNLOCK __libc_lock_unlock (envlock)
57 /* In the GNU C library we must keep the namespace clean. */
59 # define setenv __setenv
60 # define clearenv __clearenv
61 # define tfind __tfind
62 # define tsearch __tsearch
65 /* In the GNU C library implementation we try to be more clever and
66 allow arbitrarily many changes of the environment given that the used
67 values are from a small set. Outside glibc this will eat up all
68 memory after a while. */
69 #if defined _LIBC || (defined HAVE_SEARCH_H && defined HAVE_TSEARCH \
71 # define USE_TSEARCH 1
73 typedef int (*compar_fn_t) (const void *, const void *);
75 /* This is a pointer to the root of the search tree with the known
77 static void *known_values;
79 # define KNOWN_VALUE(Str) \
81 void *value = tfind (Str, &known_values, (compar_fn_t) strcmp); \
82 value != NULL ? *(char **) value : NULL; \
84 # define STORE_VALUE(Str) \
85 tsearch (Str, &known_values, (compar_fn_t) strcmp)
90 # define KNOWN_VALUE(Str) NULL
91 # define STORE_VALUE(Str) do { } while (0)
96 /* If this variable is not a null pointer we allocated the current
98 static char **last_environ;
101 /* This function is used by `setenv' and `putenv'. The difference between
102 the two functions is that for the former must create a new string which
103 is then placed in the environment, while the argument of `putenv'
104 must be used directly. This is all complicated by the fact that we try
105 to reuse values once generated for a `setenv' call since we can never
108 __add_to_environ (const char *name, const char *value, const char *combined,
112 register size_t size;
113 const size_t namelen = strlen (name);
114 const size_t vallen = value != NULL ? strlen (value) + 1 : 0;
118 /* We have to get the pointer now that we have the lock and not earlier
119 since another thread might have created a new environment. */
125 for (; *ep != NULL; ++ep)
126 if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
132 if (ep == NULL || *ep == NULL)
139 /* We allocated this space; we can extend it. */
141 (char **) (last_environ == NULL
142 ? malloc ((size + 2) * sizeof (char *))
143 : realloc (last_environ, (size + 2) * sizeof (char *)));
144 if (new_environ == NULL)
150 /* If the whole entry is given add it. */
151 if (combined != NULL)
152 /* We must not add the string to the search tree since it belongs
154 new_environ[size] = (char *) combined;
157 /* See whether the value is already known. */
160 new_value = (char *) alloca (namelen + 1 + vallen);
161 __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
164 new_value = (char *) malloca (namelen + 1 + vallen);
165 if (new_value == NULL)
167 __set_errno (ENOMEM);
171 memcpy (new_value, name, namelen);
172 new_value[namelen] = '=';
173 memcpy (&new_value[namelen + 1], value, vallen);
176 new_environ[size] = KNOWN_VALUE (new_value);
177 if (new_environ[size] == NULL)
180 new_environ[size] = (char *) malloc (namelen + 1 + vallen);
181 if (new_environ[size] == NULL)
183 #if defined USE_TSEARCH && !defined _LIBC
186 __set_errno (ENOMEM);
192 memcpy (new_environ[size], new_value, namelen + 1 + vallen);
194 memcpy (new_environ[size], name, namelen);
195 new_environ[size][namelen] = '=';
196 memcpy (&new_environ[size][namelen + 1], value, vallen);
198 /* And save the value now. We cannot do this when we remove
199 the string since then we cannot decide whether it is a
200 user string or not. */
201 STORE_VALUE (new_environ[size]);
203 #if defined USE_TSEARCH && !defined _LIBC
208 if (__environ != last_environ)
209 memcpy ((char *) new_environ, (char *) __environ,
210 size * sizeof (char *));
212 new_environ[size + 1] = NULL;
214 last_environ = __environ = new_environ;
220 /* Use the user string if given. */
221 if (combined != NULL)
222 np = (char *) combined;
228 new_value = alloca (namelen + 1 + vallen);
229 __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
232 new_value = malloca (namelen + 1 + vallen);
233 if (new_value == NULL)
235 __set_errno (ENOMEM);
239 memcpy (new_value, name, namelen);
240 new_value[namelen] = '=';
241 memcpy (&new_value[namelen + 1], value, vallen);
244 np = KNOWN_VALUE (new_value);
248 np = malloc (namelen + 1 + vallen);
251 #if defined USE_TSEARCH && !defined _LIBC
254 __set_errno (ENOMEM);
260 memcpy (np, new_value, namelen + 1 + vallen);
262 memcpy (np, name, namelen);
264 memcpy (&np[namelen + 1], value, vallen);
266 /* And remember the value. */
269 #if defined USE_TSEARCH && !defined _LIBC
283 setenv (const char *name, const char *value, int replace)
285 return __add_to_environ (name, value, NULL, replace);
288 /* The `clearenv' was planned to be added to POSIX.1 but probably
289 never made it. Nevertheless the POSIX.9 standard (POSIX bindings
290 for Fortran 77) requires this function. */
296 if (__environ == last_environ && __environ != NULL)
298 /* We allocated this environment so we can free it. */
303 /* Clear the environment pointer removes the whole environment. */
315 /* Remove all traces. */
318 /* Now remove the search tree. */
319 __tdestroy (known_values, free);
322 text_set_element (__libc_subfreeres, free_mem);
327 weak_alias (__setenv, setenv)
328 weak_alias (__clearenv, clearenv)
331 #endif /* _LIBC || !HAVE_SETENV */