1 /* Copyright (C) 1992,1995-1999,2000-2003,2005 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))
37 # define __environ environ
38 # ifndef HAVE_ENVIRON_DECL
39 extern char **environ;
44 /* This lock protects against simultaneous modifications of `environ'. */
45 # include <bits/libc-lock.h>
46 __libc_lock_define_initialized (static, envlock)
47 # define LOCK __libc_lock_lock (envlock)
48 # define UNLOCK __libc_lock_unlock (envlock)
54 /* In the GNU C library we must keep the namespace clean. */
56 # define setenv __setenv
57 # define clearenv __clearenv
58 # define tfind __tfind
59 # define tsearch __tsearch
62 /* In the GNU C library implementation we try to be more clever and
63 allow arbitrarily many changes of the environment given that the used
64 values are from a small set. Outside glibc this will eat up all
65 memory after a while. */
66 #if defined _LIBC || (defined HAVE_SEARCH_H && defined HAVE_TSEARCH \
68 # define USE_TSEARCH 1
70 typedef int (*compar_fn_t) (const void *, const void *);
72 /* This is a pointer to the root of the search tree with the known
74 static void *known_values;
76 # define KNOWN_VALUE(Str) \
78 void *value = tfind (Str, &known_values, (compar_fn_t) strcmp); \
79 value != NULL ? *(char **) value : NULL; \
81 # define STORE_VALUE(Str) \
82 tsearch (Str, &known_values, (compar_fn_t) strcmp)
87 # define KNOWN_VALUE(Str) NULL
88 # define STORE_VALUE(Str) do { } while (0)
93 /* If this variable is not a null pointer we allocated the current
95 static char **last_environ;
98 /* This function is used by `setenv' and `putenv'. The difference between
99 the two functions is that for the former must create a new string which
100 is then placed in the environment, while the argument of `putenv'
101 must be used directly. This is all complicated by the fact that we try
102 to reuse values once generated for a `setenv' call since we can never
105 __add_to_environ (const char *name, const char *value, const char *combined,
109 register size_t size;
110 const size_t namelen = strlen (name);
111 const size_t vallen = value != NULL ? strlen (value) + 1 : 0;
115 /* We have to get the pointer now that we have the lock and not earlier
116 since another thread might have created a new environment. */
122 for (; *ep != NULL; ++ep)
123 if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
129 if (ep == NULL || *ep == NULL)
136 /* We allocated this space; we can extend it. */
138 (char **) (last_environ == NULL
139 ? malloc ((size + 2) * sizeof (char *))
140 : realloc (last_environ, (size + 2) * sizeof (char *)));
141 if (new_environ == NULL)
147 /* If the whole entry is given add it. */
148 if (combined != NULL)
149 /* We must not add the string to the search tree since it belongs
151 new_environ[size] = (char *) combined;
154 /* See whether the value is already known. */
157 new_value = (char *) alloca (namelen + 1 + vallen);
158 __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
161 new_value = (char *) allocsa (namelen + 1 + vallen);
162 if (new_value == NULL)
164 __set_errno (ENOMEM);
168 memcpy (new_value, name, namelen);
169 new_value[namelen] = '=';
170 memcpy (&new_value[namelen + 1], value, vallen);
173 new_environ[size] = KNOWN_VALUE (new_value);
174 if (new_environ[size] == NULL)
177 new_environ[size] = (char *) malloc (namelen + 1 + vallen);
178 if (new_environ[size] == NULL)
180 #if defined USE_TSEARCH && !defined _LIBC
183 __set_errno (ENOMEM);
189 memcpy (new_environ[size], new_value, namelen + 1 + vallen);
191 memcpy (new_environ[size], name, namelen);
192 new_environ[size][namelen] = '=';
193 memcpy (&new_environ[size][namelen + 1], value, vallen);
195 /* And save the value now. We cannot do this when we remove
196 the string since then we cannot decide whether it is a
197 user string or not. */
198 STORE_VALUE (new_environ[size]);
200 #if defined USE_TSEARCH && !defined _LIBC
205 if (__environ != last_environ)
206 memcpy ((char *) new_environ, (char *) __environ,
207 size * sizeof (char *));
209 new_environ[size + 1] = NULL;
211 last_environ = __environ = new_environ;
217 /* Use the user string if given. */
218 if (combined != NULL)
219 np = (char *) combined;
225 new_value = alloca (namelen + 1 + vallen);
226 __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
229 new_value = allocsa (namelen + 1 + vallen);
230 if (new_value == NULL)
232 __set_errno (ENOMEM);
236 memcpy (new_value, name, namelen);
237 new_value[namelen] = '=';
238 memcpy (&new_value[namelen + 1], value, vallen);
241 np = KNOWN_VALUE (new_value);
245 np = malloc (namelen + 1 + vallen);
248 #if defined USE_TSEARCH && !defined _LIBC
251 __set_errno (ENOMEM);
257 memcpy (np, new_value, namelen + 1 + vallen);
259 memcpy (np, name, namelen);
261 memcpy (&np[namelen + 1], value, vallen);
263 /* And remember the value. */
266 #if defined USE_TSEARCH && !defined _LIBC
280 setenv (const char *name, const char *value, int replace)
282 return __add_to_environ (name, value, NULL, replace);
285 /* The `clearenv' was planned to be added to POSIX.1 but probably
286 never made it. Nevertheless the POSIX.9 standard (POSIX bindings
287 for Fortran 77) requires this function. */
293 if (__environ == last_environ && __environ != NULL)
295 /* We allocated this environment so we can free it. */
300 /* Clear the environment pointer removes the whole environment. */
312 /* Remove all traces. */
315 /* Now remove the search tree. */
316 __tdestroy (known_values, free);
319 text_set_element (__libc_subfreeres, free_mem);
324 weak_alias (__setenv, setenv)
325 weak_alias (__clearenv, clearenv)