1 /* Copyright (C) 1992, 1995-2003, 2005-2011 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/>. */
18 # define _GL_USE_STDLIB_ALLOC 1
22 /* Don't use __attribute__ __nonnull__ in this compilation unit. Otherwise gcc
23 optimizes away the name == NULL test below. */
24 #define _GL_ARG_NONNULL(params)
33 # define __set_errno(ev) ((errno) = (ev))
37 #if _LIBC || HAVE_UNISTD_H
45 #if _LIBC || !HAVE_SETENV
48 # define __environ environ
52 /* This lock protects against simultaneous modifications of `environ'. */
53 # include <bits/libc-lock.h>
54 __libc_lock_define_initialized (static, envlock)
55 # define LOCK __libc_lock_lock (envlock)
56 # define UNLOCK __libc_lock_unlock (envlock)
62 /* In the GNU C library we must keep the namespace clean. */
64 # define setenv __setenv
65 # define clearenv __clearenv
66 # define tfind __tfind
67 # define tsearch __tsearch
70 /* In the GNU C library implementation we try to be more clever and
71 allow arbitrarily many changes of the environment given that the used
72 values are from a small set. Outside glibc this will eat up all
73 memory after a while. */
74 #if defined _LIBC || (defined HAVE_SEARCH_H && defined HAVE_TSEARCH \
76 # define USE_TSEARCH 1
78 typedef int (*compar_fn_t) (const void *, const void *);
80 /* This is a pointer to the root of the search tree with the known
82 static void *known_values;
84 # define KNOWN_VALUE(Str) \
86 void *value = tfind (Str, &known_values, (compar_fn_t) strcmp); \
87 value != NULL ? *(char **) value : NULL; \
89 # define STORE_VALUE(Str) \
90 tsearch (Str, &known_values, (compar_fn_t) strcmp)
95 # define KNOWN_VALUE(Str) NULL
96 # define STORE_VALUE(Str) do { } while (0)
101 /* If this variable is not a null pointer we allocated the current
103 static char **last_environ;
106 /* This function is used by `setenv' and `putenv'. The difference between
107 the two functions is that for the former must create a new string which
108 is then placed in the environment, while the argument of `putenv'
109 must be used directly. This is all complicated by the fact that we try
110 to reuse values once generated for a `setenv' call since we can never
113 __add_to_environ (const char *name, const char *value, const char *combined,
118 const size_t namelen = strlen (name);
119 const size_t vallen = value != NULL ? strlen (value) + 1 : 0;
123 /* We have to get the pointer now that we have the lock and not earlier
124 since another thread might have created a new environment. */
130 for (; *ep != NULL; ++ep)
131 if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
137 if (ep == NULL || *ep == NULL)
144 /* We allocated this space; we can extend it. */
146 (char **) (last_environ == NULL
147 ? malloc ((size + 2) * sizeof (char *))
148 : realloc (last_environ, (size + 2) * sizeof (char *)));
149 if (new_environ == NULL)
151 /* It's easier to set errno to ENOMEM than to rely on the
152 'malloc-posix' and 'realloc-posix' gnulib modules. */
153 __set_errno (ENOMEM);
158 /* If the whole entry is given add it. */
159 if (combined != NULL)
160 /* We must not add the string to the search tree since it belongs
162 new_environ[size] = (char *) combined;
165 /* See whether the value is already known. */
168 new_value = (char *) alloca (namelen + 1 + vallen);
169 __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
172 new_value = (char *) malloca (namelen + 1 + vallen);
173 if (new_value == NULL)
175 __set_errno (ENOMEM);
179 memcpy (new_value, name, namelen);
180 new_value[namelen] = '=';
181 memcpy (&new_value[namelen + 1], value, vallen);
184 new_environ[size] = KNOWN_VALUE (new_value);
185 if (new_environ[size] == NULL)
188 new_environ[size] = (char *) malloc (namelen + 1 + vallen);
189 if (new_environ[size] == NULL)
191 #if defined USE_TSEARCH && !defined _LIBC
194 __set_errno (ENOMEM);
200 memcpy (new_environ[size], new_value, namelen + 1 + vallen);
202 memcpy (new_environ[size], name, namelen);
203 new_environ[size][namelen] = '=';
204 memcpy (&new_environ[size][namelen + 1], value, vallen);
206 /* And save the value now. We cannot do this when we remove
207 the string since then we cannot decide whether it is a
208 user string or not. */
209 STORE_VALUE (new_environ[size]);
211 #if defined USE_TSEARCH && !defined _LIBC
216 if (__environ != last_environ)
217 memcpy ((char *) new_environ, (char *) __environ,
218 size * sizeof (char *));
220 new_environ[size + 1] = NULL;
222 last_environ = __environ = new_environ;
228 /* Use the user string if given. */
229 if (combined != NULL)
230 np = (char *) combined;
236 new_value = alloca (namelen + 1 + vallen);
237 __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
240 new_value = malloca (namelen + 1 + vallen);
241 if (new_value == NULL)
243 __set_errno (ENOMEM);
247 memcpy (new_value, name, namelen);
248 new_value[namelen] = '=';
249 memcpy (&new_value[namelen + 1], value, vallen);
252 np = KNOWN_VALUE (new_value);
256 np = (char *) malloc (namelen + 1 + vallen);
259 #if defined USE_TSEARCH && !defined _LIBC
262 __set_errno (ENOMEM);
268 memcpy (np, new_value, namelen + 1 + vallen);
270 memcpy (np, name, namelen);
272 memcpy (&np[namelen + 1], value, vallen);
274 /* And remember the value. */
277 #if defined USE_TSEARCH && !defined _LIBC
291 setenv (const char *name, const char *value, int replace)
293 if (name == NULL || *name == '\0' || strchr (name, '=') != NULL)
295 __set_errno (EINVAL);
299 return __add_to_environ (name, value, NULL, replace);
302 /* The `clearenv' was planned to be added to POSIX.1 but probably
303 never made it. Nevertheless the POSIX.9 standard (POSIX bindings
304 for Fortran 77) requires this function. */
310 if (__environ == last_environ && __environ != NULL)
312 /* We allocated this environment so we can free it. */
317 /* Clear the environment pointer removes the whole environment. */
329 /* Remove all traces. */
332 /* Now remove the search tree. */
333 __tdestroy (known_values, free);
336 text_set_element (__libc_subfreeres, free_mem);
341 weak_alias (__setenv, setenv)
342 weak_alias (__clearenv, clearenv)
345 #endif /* _LIBC || !HAVE_SETENV */
347 /* The rest of this file is called into use when replacing an existing
348 but buggy setenv. Known bugs include failure to diagnose invalid
349 name, and consuming a leading '=' from value. */
353 # define STREQ(a, b) (strcmp (a, b) == 0)
356 rpl_setenv (const char *name, const char *value, int replace)
359 if (!name || !*name || strchr (name, '='))
364 /* Call the real setenv even if replace is 0, in case implementation
365 has underlying data to update, such as when environ changes. */
366 result = setenv (name, value, replace);
367 if (result == 0 && replace && *value == '=')
369 char *tmp = getenv (name);
370 if (!STREQ (tmp, value))
373 size_t len = strlen (value);
374 tmp = malloca (len + 2);
375 /* Since leading '=' is eaten, double it up. */
377 memcpy (tmp + 1, value, len + 1);
378 result = setenv (name, tmp, replace);
387 #endif /* HAVE_SETENV */