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))
31 #if _LIBC || HAVE_STDLIB_H
34 #if _LIBC || HAVE_STRING_H
37 #if _LIBC || HAVE_UNISTD_H
41 /* For those losing systems which don't have 'alloca' we have to add
42 some additional code emulating it. */
43 #if _LIBC || HAVE_ALLOCA
44 # define freea(p) /* nothing */
46 # define alloca(n) malloc (n)
47 # define freea(p) free (p)
51 # define __environ environ
52 # ifndef HAVE_ENVIRON_DECL
53 extern char **environ;
58 /* This lock protects against simultaneous modifications of `environ'. */
59 # include <bits/libc-lock.h>
60 __libc_lock_define_initialized (static, envlock)
61 # define LOCK __libc_lock_lock (envlock)
62 # define UNLOCK __libc_lock_unlock (envlock)
68 /* In the GNU C library we must keep the namespace clean. */
70 # define setenv __setenv
71 # define clearenv __clearenv
72 # define tfind __tfind
73 # define tsearch __tsearch
76 /* In the GNU C library implementation we try to be more clever and
77 allow arbitrarily many changes of the environment given that the used
78 values are from a small set. Outside glibc this will eat up all
79 memory after a while. */
80 #if defined _LIBC || (defined HAVE_SEARCH_H && defined HAVE_TSEARCH \
82 # define USE_TSEARCH 1
84 typedef int (*compar_fn_t) (const void *, const void *);
86 /* This is a pointer to the root of the search tree with the known
88 static void *known_values;
90 # define KNOWN_VALUE(Str) \
92 void *value = tfind (Str, &known_values, (compar_fn_t) strcmp); \
93 value != NULL ? *(char **) value : NULL; \
95 # define STORE_VALUE(Str) \
96 tsearch (Str, &known_values, (compar_fn_t) strcmp)
101 # define KNOWN_VALUE(Str) NULL
102 # define STORE_VALUE(Str) do { } while (0)
107 /* If this variable is not a null pointer we allocated the current
109 static char **last_environ;
112 /* This function is used by `setenv' and `putenv'. The difference between
113 the two functions is that for the former must create a new string which
114 is then placed in the environment, while the argument of `putenv'
115 must be used directly. This is all complicated by the fact that we try
116 to reuse values once generated for a `setenv' call since we can never
119 __add_to_environ (const char *name, const char *value, const char *combined,
123 register size_t size;
124 const size_t namelen = strlen (name);
125 const size_t vallen = value != NULL ? strlen (value) + 1 : 0;
129 /* We have to get the pointer now that we have the lock and not earlier
130 since another thread might have created a new environment. */
136 for (; *ep != NULL; ++ep)
137 if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
143 if (ep == NULL || *ep == NULL)
150 /* We allocated this space; we can extend it. */
152 (char **) (last_environ == NULL
153 ? malloc ((size + 2) * sizeof (char *))
154 : realloc (last_environ, (size + 2) * sizeof (char *)));
155 if (new_environ == NULL)
161 /* If the whole entry is given add it. */
162 if (combined != NULL)
163 /* We must not add the string to the search tree since it belongs
165 new_environ[size] = (char *) combined;
168 /* See whether the value is already known. */
170 new_value = (char *) alloca (namelen + 1 + vallen);
172 __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
175 memcpy (new_value, name, namelen);
176 new_value[namelen] = '=';
177 memcpy (&new_value[namelen + 1], value, vallen);
180 new_environ[size] = KNOWN_VALUE (new_value);
181 if (new_environ[size] == NULL)
184 new_environ[size] = (char *) malloc (namelen + 1 + vallen);
185 if (new_environ[size] == NULL)
190 __set_errno (ENOMEM);
196 memcpy (new_environ[size], new_value, namelen + 1 + vallen);
198 memcpy (new_environ[size], name, namelen);
199 new_environ[size][namelen] = '=';
200 memcpy (&new_environ[size][namelen + 1], value, vallen);
202 /* And save the value now. We cannot do this when we remove
203 the string since then we cannot decide whether it is a
204 user string or not. */
205 STORE_VALUE (new_environ[size]);
212 if (__environ != last_environ)
213 memcpy ((char *) new_environ, (char *) __environ,
214 size * sizeof (char *));
216 new_environ[size + 1] = NULL;
218 last_environ = __environ = new_environ;
224 /* Use the user string if given. */
225 if (combined != NULL)
226 np = (char *) combined;
230 char *new_value = alloca (namelen + 1 + vallen);
232 __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
235 memcpy (new_value, name, namelen);
236 new_value[namelen] = '=';
237 memcpy (&new_value[namelen + 1], value, vallen);
240 np = KNOWN_VALUE (new_value);
244 np = malloc (namelen + 1 + vallen);
255 memcpy (np, new_value, namelen + 1 + vallen);
257 memcpy (np, name, namelen);
259 memcpy (&np[namelen + 1], value, vallen);
261 /* And remember the value. */
278 setenv (const char *name, const char *value, int replace)
280 return __add_to_environ (name, value, NULL, replace);
283 /* The `clearenv' was planned to be added to POSIX.1 but probably
284 never made it. Nevertheless the POSIX.9 standard (POSIX bindings
285 for Fortran 77) requires this function. */
291 if (__environ == last_environ && __environ != NULL)
293 /* We allocated this environment so we can free it. */
298 /* Clear the environment pointer removes the whole environment. */
310 /* Remove all traces. */
313 /* Now remove the search tree. */
314 __tdestroy (known_values, free);
317 text_set_element (__libc_subfreeres, free_mem);
322 weak_alias (__setenv, setenv)
323 weak_alias (__clearenv, clearenv)