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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
25 # if !defined errno && !defined HAVE_ERRNO_DECL
28 # define __set_errno(ev) ((errno) = (ev))
33 #if _LIBC || HAVE_UNISTD_H
37 /* For those losing systems which don't have 'alloca' we have to add
38 some additional code emulating it. */
39 #if _LIBC || HAVE_ALLOCA
40 # define freea(p) /* nothing */
42 # define alloca(n) malloc (n)
43 # define freea(p) free (p)
47 # define __environ environ
48 # ifndef HAVE_ENVIRON_DECL
49 extern char **environ;
54 /* This lock protects against simultaneous modifications of `environ'. */
55 # include <bits/libc-lock.h>
56 __libc_lock_define_initialized (static, envlock)
57 # define LOCK __libc_lock_lock (envlock)
58 # define UNLOCK __libc_lock_unlock (envlock)
64 /* In the GNU C library we must keep the namespace clean. */
66 # define setenv __setenv
67 # define clearenv __clearenv
68 # define tfind __tfind
69 # define tsearch __tsearch
72 /* In the GNU C library implementation we try to be more clever and
73 allow arbitrarily many changes of the environment given that the used
74 values are from a small set. Outside glibc this will eat up all
75 memory after a while. */
76 #if defined _LIBC || (defined HAVE_SEARCH_H && defined HAVE_TSEARCH \
78 # define USE_TSEARCH 1
80 typedef int (*compar_fn_t) (const void *, const void *);
82 /* This is a pointer to the root of the search tree with the known
84 static void *known_values;
86 # define KNOWN_VALUE(Str) \
88 void *value = tfind (Str, &known_values, (compar_fn_t) strcmp); \
89 value != NULL ? *(char **) value : NULL; \
91 # define STORE_VALUE(Str) \
92 tsearch (Str, &known_values, (compar_fn_t) strcmp)
97 # define KNOWN_VALUE(Str) NULL
98 # define STORE_VALUE(Str) do { } while (0)
103 /* If this variable is not a null pointer we allocated the current
105 static char **last_environ;
108 /* This function is used by `setenv' and `putenv'. The difference between
109 the two functions is that for the former must create a new string which
110 is then placed in the environment, while the argument of `putenv'
111 must be used directly. This is all complicated by the fact that we try
112 to reuse values once generated for a `setenv' call since we can never
115 __add_to_environ (const char *name, const char *value, const char *combined,
119 register size_t size;
120 const size_t namelen = strlen (name);
121 const size_t vallen = value != NULL ? strlen (value) + 1 : 0;
125 /* We have to get the pointer now that we have the lock and not earlier
126 since another thread might have created a new environment. */
132 for (; *ep != NULL; ++ep)
133 if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
139 if (ep == NULL || *ep == NULL)
146 /* We allocated this space; we can extend it. */
148 (char **) (last_environ == NULL
149 ? malloc ((size + 2) * sizeof (char *))
150 : realloc (last_environ, (size + 2) * sizeof (char *)));
151 if (new_environ == NULL)
157 /* If the whole entry is given add it. */
158 if (combined != NULL)
159 /* We must not add the string to the search tree since it belongs
161 new_environ[size] = (char *) combined;
164 /* See whether the value is already known. */
166 new_value = (char *) alloca (namelen + 1 + vallen);
168 __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
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)
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]);
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;
226 char *new_value = alloca (namelen + 1 + vallen);
228 __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
231 memcpy (new_value, name, namelen);
232 new_value[namelen] = '=';
233 memcpy (&new_value[namelen + 1], value, vallen);
236 np = KNOWN_VALUE (new_value);
240 np = malloc (namelen + 1 + vallen);
251 memcpy (np, new_value, namelen + 1 + vallen);
253 memcpy (np, name, namelen);
255 memcpy (&np[namelen + 1], value, vallen);
257 /* And remember the value. */
274 setenv (const char *name, const char *value, int replace)
276 return __add_to_environ (name, value, NULL, replace);
279 /* The `clearenv' was planned to be added to POSIX.1 but probably
280 never made it. Nevertheless the POSIX.9 standard (POSIX bindings
281 for Fortran 77) requires this function. */
287 if (__environ == last_environ && __environ != NULL)
289 /* We allocated this environment so we can free it. */
294 /* Clear the environment pointer removes the whole environment. */
306 /* Remove all traces. */
309 /* Now remove the search tree. */
310 __tdestroy (known_values, free);
313 text_set_element (__libc_subfreeres, free_mem);
318 weak_alias (__setenv, setenv)
319 weak_alias (__clearenv, clearenv)