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
68 /* Use the system functions, not the gnulib overrides in this file. */
73 /* In the GNU C library implementation we try to be more clever and
74 allow arbitrarily many changes of the environment given that the used
75 values are from a small set. Outside glibc this will eat up all
76 memory after a while. */
77 #if defined _LIBC || (defined HAVE_SEARCH_H && defined HAVE_TSEARCH \
79 # define USE_TSEARCH 1
81 typedef int (*compar_fn_t) (const void *, const void *);
83 /* This is a pointer to the root of the search tree with the known
85 static void *known_values;
87 # define KNOWN_VALUE(Str) \
89 void *value = tfind (Str, &known_values, (compar_fn_t) strcmp); \
90 value != NULL ? *(char **) value : NULL; \
92 # define STORE_VALUE(Str) \
93 tsearch (Str, &known_values, (compar_fn_t) strcmp)
98 # define KNOWN_VALUE(Str) NULL
99 # define STORE_VALUE(Str) do { } while (0)
104 /* If this variable is not a null pointer we allocated the current
106 static char **last_environ;
109 /* This function is used by `setenv' and `putenv'. The difference between
110 the two functions is that for the former must create a new string which
111 is then placed in the environment, while the argument of `putenv'
112 must be used directly. This is all complicated by the fact that we try
113 to reuse values once generated for a `setenv' call since we can never
116 __add_to_environ (const char *name, const char *value, const char *combined,
121 const size_t namelen = strlen (name);
122 const size_t vallen = value != NULL ? strlen (value) + 1 : 0;
126 /* We have to get the pointer now that we have the lock and not earlier
127 since another thread might have created a new environment. */
133 for (; *ep != NULL; ++ep)
134 if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
140 if (ep == NULL || *ep == NULL)
147 /* We allocated this space; we can extend it. */
149 (char **) (last_environ == NULL
150 ? malloc ((size + 2) * sizeof (char *))
151 : realloc (last_environ, (size + 2) * sizeof (char *)));
152 if (new_environ == NULL)
154 /* It's easier to set errno to ENOMEM than to rely on the
155 'malloc-posix' and 'realloc-posix' gnulib modules. */
156 __set_errno (ENOMEM);
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. */
171 new_value = (char *) alloca (namelen + 1 + vallen);
172 __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
175 new_value = (char *) malloca (namelen + 1 + vallen);
176 if (new_value == NULL)
178 __set_errno (ENOMEM);
182 memcpy (new_value, name, namelen);
183 new_value[namelen] = '=';
184 memcpy (&new_value[namelen + 1], value, vallen);
187 new_environ[size] = KNOWN_VALUE (new_value);
188 if (new_environ[size] == NULL)
191 new_environ[size] = (char *) malloc (namelen + 1 + vallen);
192 if (new_environ[size] == NULL)
194 #if defined USE_TSEARCH && !defined _LIBC
197 __set_errno (ENOMEM);
203 memcpy (new_environ[size], new_value, namelen + 1 + vallen);
205 memcpy (new_environ[size], name, namelen);
206 new_environ[size][namelen] = '=';
207 memcpy (&new_environ[size][namelen + 1], value, vallen);
209 /* And save the value now. We cannot do this when we remove
210 the string since then we cannot decide whether it is a
211 user string or not. */
212 STORE_VALUE (new_environ[size]);
214 #if defined USE_TSEARCH && !defined _LIBC
219 if (__environ != last_environ)
220 memcpy ((char *) new_environ, (char *) __environ,
221 size * sizeof (char *));
223 new_environ[size + 1] = NULL;
225 last_environ = __environ = new_environ;
231 /* Use the user string if given. */
232 if (combined != NULL)
233 np = (char *) combined;
239 new_value = alloca (namelen + 1 + vallen);
240 __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
243 new_value = malloca (namelen + 1 + vallen);
244 if (new_value == NULL)
246 __set_errno (ENOMEM);
250 memcpy (new_value, name, namelen);
251 new_value[namelen] = '=';
252 memcpy (&new_value[namelen + 1], value, vallen);
255 np = KNOWN_VALUE (new_value);
259 np = (char *) malloc (namelen + 1 + vallen);
262 #if defined USE_TSEARCH && !defined _LIBC
265 __set_errno (ENOMEM);
271 memcpy (np, new_value, namelen + 1 + vallen);
273 memcpy (np, name, namelen);
275 memcpy (&np[namelen + 1], value, vallen);
277 /* And remember the value. */
280 #if defined USE_TSEARCH && !defined _LIBC
294 setenv (const char *name, const char *value, int replace)
296 if (name == NULL || *name == '\0' || strchr (name, '=') != NULL)
298 __set_errno (EINVAL);
302 return __add_to_environ (name, value, NULL, replace);
305 /* The `clearenv' was planned to be added to POSIX.1 but probably
306 never made it. Nevertheless the POSIX.9 standard (POSIX bindings
307 for Fortran 77) requires this function. */
313 if (__environ == last_environ && __environ != NULL)
315 /* We allocated this environment so we can free it. */
320 /* Clear the environment pointer removes the whole environment. */
332 /* Remove all traces. */
335 /* Now remove the search tree. */
336 __tdestroy (known_values, free);
339 text_set_element (__libc_subfreeres, free_mem);
344 weak_alias (__setenv, setenv)
345 weak_alias (__clearenv, clearenv)
348 #endif /* _LIBC || !HAVE_SETENV */
350 /* The rest of this file is called into use when replacing an existing
351 but buggy setenv. Known bugs include failure to diagnose invalid
352 name, and consuming a leading '=' from value. */
356 # define STREQ(a, b) (strcmp (a, b) == 0)
359 rpl_setenv (const char *name, const char *value, int replace)
362 if (!name || !*name || strchr (name, '='))
367 /* Call the real setenv even if replace is 0, in case implementation
368 has underlying data to update, such as when environ changes. */
369 result = setenv (name, value, replace);
370 if (result == 0 && replace && *value == '=')
372 char *tmp = getenv (name);
373 if (!STREQ (tmp, value))
376 size_t len = strlen (value);
377 tmp = malloca (len + 2);
378 /* Since leading '=' is eaten, double it up. */
380 memcpy (tmp + 1, value, len + 1);
381 result = setenv (name, tmp, replace);
390 #endif /* HAVE_SETENV */