1 /* Copyright (C) 1992,95,96,97,98,99,2000,2001 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 Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the 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 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, write to the Free
16 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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
42 # define __environ environ
43 # ifndef HAVE_ENVIRON_DECL
44 extern char **environ
;
49 /* This lock protects against simultaneous modifications of `environ'. */
50 # include <bits/libc-lock.h>
51 __libc_lock_define_initialized (static, envlock
)
52 # define LOCK __libc_lock_lock (envlock)
53 # define UNLOCK __libc_lock_unlock (envlock)
59 /* In the GNU C library we must keep the namespace clean. */
61 # define setenv __setenv
62 # define unsetenv __unsetenv
63 # define clearenv __clearenv
64 # define tfind __tfind
65 # define tsearch __tsearch
68 /* In the GNU C library implementation we try to be more clever and
69 allow arbitrarily many changes of the environment given that the used
70 values are from a small set. Outside glibc this will eat up all
71 memory after a while. */
72 #if defined _LIBC || (defined HAVE_SEARCH_H && defined HAVE_TSEARCH \
74 # define USE_TSEARCH 1
77 /* This is a pointer to the root of the search tree with the known
79 static void *known_values
;
81 # define KNOWN_VALUE(Str) \
83 void *value = tfind (Str, &known_values, (__compar_fn_t) strcmp); \
84 value != NULL ? *(char **) value : NULL; \
86 # define STORE_VALUE(Str) \
87 tsearch (Str, &known_values, (__compar_fn_t) strcmp)
92 # define KNOWN_VALUE(Str) NULL
93 # define STORE_VALUE(Str) do { } while (0)
98 /* If this variable is not a null pointer we allocated the current
100 static char **last_environ
;
103 /* This function is used by `setenv' and `putenv'. The difference between
104 the two functions is that for the former must create a new string which
105 is then placed in the environment, while the argument of `putenv'
106 must be used directly. This is all complicated by the fact that we try
107 to reuse values once generated for a `setenv' call since we can never
110 __add_to_environ (name
, value
, combined
, replace
)
113 const char *combined
;
117 register size_t size
;
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. */
145 new_environ
= (char **) realloc (last_environ
,
146 (size
+ 2) * sizeof (char *));
147 if (new_environ
== NULL
)
153 /* If the whole entry is given add it. */
154 if (combined
!= NULL
)
155 /* We must not add the string to the search tree since it belongs
157 new_environ
[size
] = (char *) combined
;
160 /* See whether the value is already known. */
162 new_value
= (char *) alloca (namelen
+ 1 + vallen
);
164 __mempcpy (__mempcpy (__mempcpy (new_value
, name
, namelen
), "=", 1),
167 memcpy (new_value
, name
, namelen
);
168 new_value
[namelen
] = '=';
169 memcpy (&new_value
[namelen
+ 1], value
, vallen
);
172 new_environ
[size
] = KNOWN_VALUE (new_value
);
173 if (new_environ
[size
] == NULL
)
176 new_environ
[size
] = (char *) malloc (namelen
+ 1 + vallen
);
177 if (new_environ
[size
] == NULL
)
179 __set_errno (ENOMEM
);
185 memcpy (new_environ
[size
], new_value
, namelen
+ 1 + vallen
);
187 memcpy (new_environ
[size
], name
, namelen
);
188 new_environ
[size
][namelen
] = '=';
189 memcpy (&new_environ
[size
][namelen
+ 1], value
, vallen
);
191 /* And save the value now. We cannot do this when we remove
192 the string since then we cannot decide whether it is a
193 user string or not. */
194 STORE_VALUE (new_environ
[size
]);
198 if (__environ
!= last_environ
)
199 memcpy ((char *) new_environ
, (char *) __environ
,
200 size
* sizeof (char *));
202 new_environ
[size
+ 1] = NULL
;
204 last_environ
= __environ
= new_environ
;
210 /* Use the user string if given. */
211 if (combined
!= NULL
)
212 np
= (char *) combined
;
216 char *new_value
= alloca (namelen
+ 1 + vallen
);
218 __mempcpy (__mempcpy (__mempcpy (new_value
, name
, namelen
), "=", 1),
221 memcpy (new_value
, name
, namelen
);
222 new_value
[namelen
] = '=';
223 memcpy (&new_value
[namelen
+ 1], value
, vallen
);
226 np
= KNOWN_VALUE (new_value
);
230 np
= malloc (namelen
+ 1 + vallen
);
238 memcpy (np
, new_value
, namelen
+ 1 + vallen
);
240 memcpy (np
, name
, namelen
);
242 memcpy (&np
[namelen
+ 1], value
, vallen
);
244 /* And remember the value. */
258 setenv (name
, value
, replace
)
263 return __add_to_environ (name
, value
, NULL
, replace
);
273 if (name
== NULL
|| *name
== '\0' || strchr (name
, '=') != NULL
)
275 __set_errno (EINVAL
);
285 if (!strncmp (*ep
, name
, len
) && (*ep
)[len
] == '=')
287 /* Found it. Remove this pointer by moving later ones back. */
293 /* Continue the loop in case NAME appears again. */
303 /* The `clearenv' was planned to be added to POSIX.1 but probably
304 never made it. Nevertheless the POSIX.9 standard (POSIX bindings
305 for Fortran 77) requires this function. */
311 if (__environ
== last_environ
&& __environ
!= NULL
)
313 /* We allocated this environment so we can free it. */
318 /* 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
);
342 weak_alias (__setenv
, setenv
)
343 weak_alias (__unsetenv
, unsetenv
)
344 weak_alias (__clearenv
, clearenv
)