1 /* Copyright (C) 1992,1995-1999,2000-2002 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Library General Public License as
6 published by the Free Software Foundation; either version 2 of the
7 License, or (at your option) any later version.
9 The GNU C Library 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 GNU
12 Library General Public License for more details.
14 You should have received a copy of the GNU Library General Public
15 License along with the GNU C Library; see the file COPYING.LIB. If not,
16 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 Boston, MA 02111-1307, USA. */
25 # define alloca __builtin_alloca
30 # define alloca _alloca
38 # ifdef __hpux /* This section must match that of bison generated files. */
40 extern "C" void *alloca (unsigned int);
41 # else /* not __cplusplus */
43 # endif /* not __cplusplus */
44 # else /* not __hpux */
56 # if !defined errno && !defined HAVE_ERRNO_DECL
59 # define __set_errno(ev) ((errno) = (ev))
62 #if _LIBC || HAVE_STDLIB_H
65 #if _LIBC || HAVE_STRING_H
68 #if _LIBC || HAVE_UNISTD_H
72 /* For those losing systems which don't have 'alloca' we have to add
73 some additional code emulating it. */
74 #if _LIBC || HAVE_ALLOCA
75 # define freea(p) /* nothing */
77 # define alloca(n) malloc (n)
78 # define freea(p) free (p)
82 # define __environ environ
83 # ifndef HAVE_ENVIRON_DECL
84 extern char **environ;
89 /* This lock protects against simultaneous modifications of `environ'. */
90 # include <bits/libc-lock.h>
91 __libc_lock_define_initialized (static, envlock)
92 # define LOCK __libc_lock_lock (envlock)
93 # define UNLOCK __libc_lock_unlock (envlock)
99 /* In the GNU C library we must keep the namespace clean. */
101 # define setenv __setenv
102 # define clearenv __clearenv
103 # define tfind __tfind
104 # define tsearch __tsearch
107 /* In the GNU C library implementation we try to be more clever and
108 allow arbitrarily many changes of the environment given that the used
109 values are from a small set. Outside glibc this will eat up all
110 memory after a while. */
111 #if defined _LIBC || (defined HAVE_SEARCH_H && defined HAVE_TSEARCH \
113 # define USE_TSEARCH 1
115 typedef int (*compar_fn_t) (const void *, const void *);
117 /* This is a pointer to the root of the search tree with the known
119 static void *known_values;
121 # define KNOWN_VALUE(Str) \
123 void *value = tfind (Str, &known_values, (compar_fn_t) strcmp); \
124 value != NULL ? *(char **) value : NULL; \
126 # define STORE_VALUE(Str) \
127 tsearch (Str, &known_values, (compar_fn_t) strcmp)
132 # define KNOWN_VALUE(Str) NULL
133 # define STORE_VALUE(Str) do { } while (0)
138 /* If this variable is not a null pointer we allocated the current
140 static char **last_environ;
143 /* This function is used by `setenv' and `putenv'. The difference between
144 the two functions is that for the former must create a new string which
145 is then placed in the environment, while the argument of `putenv'
146 must be used directly. This is all complicated by the fact that we try
147 to reuse values once generated for a `setenv' call since we can never
150 __add_to_environ (const char *name, const char *value, const char *combined,
154 register size_t size;
155 const size_t namelen = strlen (name);
156 const size_t vallen = value != NULL ? strlen (value) + 1 : 0;
160 /* We have to get the pointer now that we have the lock and not earlier
161 since another thread might have created a new environment. */
167 for (; *ep != NULL; ++ep)
168 if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
174 if (ep == NULL || *ep == NULL)
181 /* We allocated this space; we can extend it. */
183 (char **) (last_environ == NULL
184 ? malloc ((size + 2) * sizeof (char *))
185 : realloc (last_environ, (size + 2) * sizeof (char *)));
186 if (new_environ == NULL)
192 /* If the whole entry is given add it. */
193 if (combined != NULL)
194 /* We must not add the string to the search tree since it belongs
196 new_environ[size] = (char *) combined;
199 /* See whether the value is already known. */
201 new_value = (char *) alloca (namelen + 1 + vallen);
203 __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
206 memcpy (new_value, name, namelen);
207 new_value[namelen] = '=';
208 memcpy (&new_value[namelen + 1], value, vallen);
211 new_environ[size] = KNOWN_VALUE (new_value);
212 if (new_environ[size] == NULL)
215 new_environ[size] = (char *) malloc (namelen + 1 + vallen);
216 if (new_environ[size] == NULL)
221 __set_errno (ENOMEM);
227 memcpy (new_environ[size], new_value, namelen + 1 + vallen);
229 memcpy (new_environ[size], name, namelen);
230 new_environ[size][namelen] = '=';
231 memcpy (&new_environ[size][namelen + 1], value, vallen);
233 /* And save the value now. We cannot do this when we remove
234 the string since then we cannot decide whether it is a
235 user string or not. */
236 STORE_VALUE (new_environ[size]);
243 if (__environ != last_environ)
244 memcpy ((char *) new_environ, (char *) __environ,
245 size * sizeof (char *));
247 new_environ[size + 1] = NULL;
249 last_environ = __environ = new_environ;
255 /* Use the user string if given. */
256 if (combined != NULL)
257 np = (char *) combined;
261 char *new_value = alloca (namelen + 1 + vallen);
263 __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
266 memcpy (new_value, name, namelen);
267 new_value[namelen] = '=';
268 memcpy (&new_value[namelen + 1], value, vallen);
271 np = KNOWN_VALUE (new_value);
275 np = malloc (namelen + 1 + vallen);
286 memcpy (np, new_value, namelen + 1 + vallen);
288 memcpy (np, name, namelen);
290 memcpy (&np[namelen + 1], value, vallen);
292 /* And remember the value. */
309 setenv (const char *name, const char *value, int replace)
311 return __add_to_environ (name, value, NULL, replace);
314 /* The `clearenv' was planned to be added to POSIX.1 but probably
315 never made it. Nevertheless the POSIX.9 standard (POSIX bindings
316 for Fortran 77) requires this function. */
322 if (__environ == last_environ && __environ != NULL)
324 /* We allocated this environment so we can free it. */
329 /* Clear the environment pointer removes the whole environment. */
341 /* Remove all traces. */
344 /* Now remove the search tree. */
345 __tdestroy (known_values, free);
348 text_set_element (__libc_subfreeres, free_mem);
353 weak_alias (__setenv, setenv)
354 weak_alias (__clearenv, clearenv)