1 /* Copyright (C) 1992, 1995-2003, 2005-2010 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 3 of the License, or
7 (at your option) any later version.
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
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
21 /* Don't use __attribute__ __nonnull__ in this compilation unit. Otherwise gcc
22 optimizes away the name == NULL test below. */
23 #define _GL_ARG_NONNULL(params)
32 # define __set_errno(ev) ((errno) = (ev))
36 #if _LIBC || HAVE_UNISTD_H
44 #if _LIBC || !HAVE_SETENV
47 # define __environ environ
51 /* This lock protects against simultaneous modifications of `environ'. */
52 # include <bits/libc-lock.h>
53 __libc_lock_define_initialized (static, envlock)
54 # define LOCK __libc_lock_lock (envlock)
55 # define UNLOCK __libc_lock_unlock (envlock)
61 /* In the GNU C library we must keep the namespace clean. */
63 # define setenv __setenv
64 # define clearenv __clearenv
65 # define tfind __tfind
66 # define tsearch __tsearch
69 /* In the GNU C library implementation we try to be more clever and
70 allow arbitrarily many changes of the environment given that the used
71 values are from a small set. Outside glibc this will eat up all
72 memory after a while. */
73 #if defined _LIBC || (defined HAVE_SEARCH_H && defined HAVE_TSEARCH \
75 # define USE_TSEARCH 1
77 typedef int (*compar_fn_t) (const void *, const void *);
79 /* This is a pointer to the root of the search tree with the known
81 static void *known_values;
83 # define KNOWN_VALUE(Str) \
85 void *value = tfind (Str, &known_values, (compar_fn_t) strcmp); \
86 value != NULL ? *(char **) value : NULL; \
88 # define STORE_VALUE(Str) \
89 tsearch (Str, &known_values, (compar_fn_t) strcmp)
94 # define KNOWN_VALUE(Str) NULL
95 # define STORE_VALUE(Str) do { } while (0)
100 /* If this variable is not a null pointer we allocated the current
102 static char **last_environ;
105 /* This function is used by `setenv' and `putenv'. The difference between
106 the two functions is that for the former must create a new string which
107 is then placed in the environment, while the argument of `putenv'
108 must be used directly. This is all complicated by the fact that we try
109 to reuse values once generated for a `setenv' call since we can never
112 __add_to_environ (const char *name, const char *value, const char *combined,
117 const size_t namelen = strlen (name);
118 const size_t vallen = value != NULL ? strlen (value) + 1 : 0;
122 /* We have to get the pointer now that we have the lock and not earlier
123 since another thread might have created a new environment. */
129 for (; *ep != NULL; ++ep)
130 if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
136 if (ep == NULL || *ep == NULL)
143 /* We allocated this space; we can extend it. */
145 (char **) (last_environ == NULL
146 ? malloc ((size + 2) * sizeof (char *))
147 : realloc (last_environ, (size + 2) * sizeof (char *)));
148 if (new_environ == NULL)
150 /* It's easier to set errno to ENOMEM than to rely on the
151 'malloc-posix' and 'realloc-posix' gnulib modules. */
152 __set_errno (ENOMEM);
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. */
167 new_value = (char *) alloca (namelen + 1 + vallen);
168 __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
171 new_value = (char *) malloca (namelen + 1 + vallen);
172 if (new_value == NULL)
174 __set_errno (ENOMEM);
178 memcpy (new_value, name, namelen);
179 new_value[namelen] = '=';
180 memcpy (&new_value[namelen + 1], value, vallen);
183 new_environ[size] = KNOWN_VALUE (new_value);
184 if (new_environ[size] == NULL)
187 new_environ[size] = (char *) malloc (namelen + 1 + vallen);
188 if (new_environ[size] == NULL)
190 #if defined USE_TSEARCH && !defined _LIBC
193 __set_errno (ENOMEM);
199 memcpy (new_environ[size], new_value, namelen + 1 + vallen);
201 memcpy (new_environ[size], name, namelen);
202 new_environ[size][namelen] = '=';
203 memcpy (&new_environ[size][namelen + 1], value, vallen);
205 /* And save the value now. We cannot do this when we remove
206 the string since then we cannot decide whether it is a
207 user string or not. */
208 STORE_VALUE (new_environ[size]);
210 #if defined USE_TSEARCH && !defined _LIBC
215 if (__environ != last_environ)
216 memcpy ((char *) new_environ, (char *) __environ,
217 size * sizeof (char *));
219 new_environ[size + 1] = NULL;
221 last_environ = __environ = new_environ;
227 /* Use the user string if given. */
228 if (combined != NULL)
229 np = (char *) combined;
235 new_value = alloca (namelen + 1 + vallen);
236 __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
239 new_value = malloca (namelen + 1 + vallen);
240 if (new_value == NULL)
242 __set_errno (ENOMEM);
246 memcpy (new_value, name, namelen);
247 new_value[namelen] = '=';
248 memcpy (&new_value[namelen + 1], value, vallen);
251 np = KNOWN_VALUE (new_value);
255 np = (char *) malloc (namelen + 1 + vallen);
258 #if defined USE_TSEARCH && !defined _LIBC
261 __set_errno (ENOMEM);
267 memcpy (np, new_value, namelen + 1 + vallen);
269 memcpy (np, name, namelen);
271 memcpy (&np[namelen + 1], value, vallen);
273 /* And remember the value. */
276 #if defined USE_TSEARCH && !defined _LIBC
290 setenv (const char *name, const char *value, int replace)
292 if (name == NULL || *name == '\0' || strchr (name, '=') != NULL)
294 __set_errno (EINVAL);
298 return __add_to_environ (name, value, NULL, replace);
301 /* The `clearenv' was planned to be added to POSIX.1 but probably
302 never made it. Nevertheless the POSIX.9 standard (POSIX bindings
303 for Fortran 77) requires this function. */
309 if (__environ == last_environ && __environ != NULL)
311 /* We allocated this environment so we can free it. */
316 /* Clear the environment pointer removes the whole environment. */
328 /* Remove all traces. */
331 /* Now remove the search tree. */
332 __tdestroy (known_values, free);
335 text_set_element (__libc_subfreeres, free_mem);
340 weak_alias (__setenv, setenv)
341 weak_alias (__clearenv, clearenv)
344 #endif /* _LIBC || !HAVE_SETENV */
346 /* The rest of this file is called into use when replacing an existing
347 but buggy setenv. Known bugs include failure to diagnose invalid
348 name, and consuming a leading '=' from value. */
352 # define STREQ(a, b) (strcmp (a, b) == 0)
355 rpl_setenv (const char *name, const char *value, int replace)
358 if (!name || !*name || strchr (name, '='))
363 /* Call the real setenv even if replace is 0, in case implementation
364 has underlying data to update, such as when environ changes. */
365 result = setenv (name, value, replace);
366 if (result == 0 && replace && *value == '=')
368 char *tmp = getenv (name);
369 if (!STREQ (tmp, value))
372 size_t len = strlen (value);
373 tmp = malloca (len + 2);
374 /* Since leading '=' is eaten, double it up. */
376 memcpy (tmp + 1, value, len + 1);
377 result = setenv (name, tmp, replace);
386 #endif /* HAVE_SETENV */