1 /* Copyright (C) 1992,1995-1999,2000-2003 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 2, or (at your option)
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 along
15 with this program; if not, write to the Free Software Foundation,
16 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
25 # define __set_errno(ev) ((errno) = (ev))
30 #if _LIBC || HAVE_UNISTD_H
39 # define __environ environ
40 # ifndef HAVE_ENVIRON_DECL
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)
56 /* In the GNU C library we must keep the namespace clean. */
58 # define setenv __setenv
59 # define clearenv __clearenv
60 # define tfind __tfind
61 # define tsearch __tsearch
64 /* In the GNU C library implementation we try to be more clever and
65 allow arbitrarily many changes of the environment given that the used
66 values are from a small set. Outside glibc this will eat up all
67 memory after a while. */
68 #if defined _LIBC || (defined HAVE_SEARCH_H && defined HAVE_TSEARCH \
70 # define USE_TSEARCH 1
72 typedef int (*compar_fn_t) (const void *, const void *);
74 /* This is a pointer to the root of the search tree with the known
76 static void *known_values;
78 # define KNOWN_VALUE(Str) \
80 void *value = tfind (Str, &known_values, (compar_fn_t) strcmp); \
81 value != NULL ? *(char **) value : NULL; \
83 # define STORE_VALUE(Str) \
84 tsearch (Str, &known_values, (compar_fn_t) strcmp)
89 # define KNOWN_VALUE(Str) NULL
90 # define STORE_VALUE(Str) do { } while (0)
95 /* If this variable is not a null pointer we allocated the current
97 static char **last_environ;
100 /* This function is used by `setenv' and `putenv'. The difference between
101 the two functions is that for the former must create a new string which
102 is then placed in the environment, while the argument of `putenv'
103 must be used directly. This is all complicated by the fact that we try
104 to reuse values once generated for a `setenv' call since we can never
107 __add_to_environ (const char *name, const char *value, const char *combined,
111 register size_t size;
112 const size_t namelen = strlen (name);
113 const size_t vallen = value != NULL ? strlen (value) + 1 : 0;
117 /* We have to get the pointer now that we have the lock and not earlier
118 since another thread might have created a new environment. */
124 for (; *ep != NULL; ++ep)
125 if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
131 if (ep == NULL || *ep == NULL)
138 /* We allocated this space; we can extend it. */
140 (char **) (last_environ == NULL
141 ? malloc ((size + 2) * sizeof (char *))
142 : realloc (last_environ, (size + 2) * sizeof (char *)));
143 if (new_environ == NULL)
149 /* If the whole entry is given add it. */
150 if (combined != NULL)
151 /* We must not add the string to the search tree since it belongs
153 new_environ[size] = (char *) combined;
156 /* See whether the value is already known. */
159 new_value = (char *) alloca (namelen + 1 + vallen);
160 __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
163 new_value = (char *) allocsa (namelen + 1 + vallen);
164 if (new_value == NULL)
166 __set_errno (ENOMEM);
170 memcpy (new_value, name, namelen);
171 new_value[namelen] = '=';
172 memcpy (&new_value[namelen + 1], value, vallen);
175 new_environ[size] = KNOWN_VALUE (new_value);
176 if (new_environ[size] == NULL)
179 new_environ[size] = (char *) malloc (namelen + 1 + vallen);
180 if (new_environ[size] == NULL)
182 #if defined USE_TSEARCH && !defined _LIBC
185 __set_errno (ENOMEM);
191 memcpy (new_environ[size], new_value, namelen + 1 + vallen);
193 memcpy (new_environ[size], name, namelen);
194 new_environ[size][namelen] = '=';
195 memcpy (&new_environ[size][namelen + 1], value, vallen);
197 /* And save the value now. We cannot do this when we remove
198 the string since then we cannot decide whether it is a
199 user string or not. */
200 STORE_VALUE (new_environ[size]);
202 #if defined USE_TSEARCH && !defined _LIBC
207 if (__environ != last_environ)
208 memcpy ((char *) new_environ, (char *) __environ,
209 size * sizeof (char *));
211 new_environ[size + 1] = NULL;
213 last_environ = __environ = new_environ;
219 /* Use the user string if given. */
220 if (combined != NULL)
221 np = (char *) combined;
227 new_value = alloca (namelen + 1 + vallen);
228 __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
231 new_value = allocsa (namelen + 1 + vallen);
232 if (new_value == NULL)
234 __set_errno (ENOMEM);
238 memcpy (new_value, name, namelen);
239 new_value[namelen] = '=';
240 memcpy (&new_value[namelen + 1], value, vallen);
243 np = KNOWN_VALUE (new_value);
247 np = malloc (namelen + 1 + vallen);
250 #if defined USE_TSEARCH && !defined _LIBC
253 __set_errno (ENOMEM);
259 memcpy (np, new_value, namelen + 1 + vallen);
261 memcpy (np, name, namelen);
263 memcpy (&np[namelen + 1], value, vallen);
265 /* And remember the value. */
268 #if defined USE_TSEARCH && !defined _LIBC
282 setenv (const char *name, const char *value, int replace)
284 return __add_to_environ (name, value, NULL, replace);
287 /* The `clearenv' was planned to be added to POSIX.1 but probably
288 never made it. Nevertheless the POSIX.9 standard (POSIX bindings
289 for Fortran 77) requires this function. */
295 if (__environ == last_environ && __environ != NULL)
297 /* We allocated this environment so we can free it. */
302 /* Clear the environment pointer removes the whole environment. */
314 /* Remove all traces. */
317 /* Now remove the search tree. */
318 __tdestroy (known_values, free);
321 text_set_element (__libc_subfreeres, free_mem);
326 weak_alias (__setenv, setenv)
327 weak_alias (__clearenv, clearenv)