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bfff8b1b | 1 | /* Copyright (C) 1992-2017 Free Software Foundation, Inc. |
f0e44959 | 2 | This file is part of the GNU C Library. |
28f540f4 | 3 | |
f0e44959 | 4 | The GNU C Library is free software; you can redistribute it and/or |
41bdb6e2 AJ |
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. | |
28f540f4 | 8 | |
f0e44959 UD |
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 | |
41bdb6e2 | 12 | Lesser General Public License for more details. |
28f540f4 | 13 | |
41bdb6e2 | 14 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 PE |
15 | License along with the GNU C Library; if not, see |
16 | <http://www.gnu.org/licenses/>. */ | |
28f540f4 | 17 | |
f0e44959 UD |
18 | #if HAVE_CONFIG_H |
19 | # include <config.h> | |
196980f5 RM |
20 | #endif |
21 | ||
03c1e456 PE |
22 | /* Pacify GCC; see the commentary about VALLEN below. This is needed |
23 | at least through GCC 4.9.2. Pacify GCC for the entire file, as | |
24 | there seems to be no way to pacify GCC selectively, only for the | |
25 | place where it's needed. Do not use DIAG_IGNORE_NEEDS_COMMENT | |
26 | here, as it's not defined yet. */ | |
f1d237df | 27 | #pragma GCC diagnostic ignored "-Wmaybe-uninitialized" |
03c1e456 | 28 | |
196980f5 | 29 | #include <errno.h> |
61c162b5 | 30 | #if !_LIBC |
ff152e3f | 31 | # if !defined errno && !defined HAVE_ERRNO_DECL |
61c162b5 UD |
32 | extern int errno; |
33 | # endif | |
34 | # define __set_errno(ev) ((errno) = (ev)) | |
35 | #endif | |
196980f5 RM |
36 | |
37 | #if _LIBC || HAVE_STDLIB_H | |
f0e44959 | 38 | # include <stdlib.h> |
196980f5 RM |
39 | #endif |
40 | #if _LIBC || HAVE_STRING_H | |
f0e44959 | 41 | # include <string.h> |
196980f5 RM |
42 | #endif |
43 | #if _LIBC || HAVE_UNISTD_H | |
f0e44959 | 44 | # include <unistd.h> |
196980f5 | 45 | #endif |
28f540f4 | 46 | |
61c162b5 | 47 | #if !_LIBC |
f0e44959 | 48 | # define __environ environ |
61c162b5 UD |
49 | # ifndef HAVE_ENVIRON_DECL |
50 | extern char **environ; | |
51 | # endif | |
28f540f4 RM |
52 | #endif |
53 | ||
61c162b5 | 54 | #if _LIBC |
9e0f4072 | 55 | /* This lock protects against simultaneous modifications of `environ'. */ |
ec999b8e | 56 | # include <libc-lock.h> |
9e0f4072 | 57 | __libc_lock_define_initialized (static, envlock) |
f0e44959 UD |
58 | # define LOCK __libc_lock_lock (envlock) |
59 | # define UNLOCK __libc_lock_unlock (envlock) | |
9e0f4072 | 60 | #else |
f0e44959 UD |
61 | # define LOCK |
62 | # define UNLOCK | |
9e0f4072 RM |
63 | #endif |
64 | ||
3e5f5557 UD |
65 | /* In the GNU C library we must keep the namespace clean. */ |
66 | #ifdef _LIBC | |
ff152e3f UD |
67 | # define setenv __setenv |
68 | # define unsetenv __unsetenv | |
3e5f5557 | 69 | # define clearenv __clearenv |
b17277cf UD |
70 | # define tfind __tfind |
71 | # define tsearch __tsearch | |
3e5f5557 UD |
72 | #endif |
73 | ||
ff152e3f | 74 | /* In the GNU C library implementation we try to be more clever and |
49c091e5 | 75 | allow arbitrarily many changes of the environment given that the used |
ff152e3f UD |
76 | values are from a small set. Outside glibc this will eat up all |
77 | memory after a while. */ | |
a709dd43 UD |
78 | #if defined _LIBC || (defined HAVE_SEARCH_H && defined HAVE_TSEARCH \ |
79 | && defined __GNUC__) | |
ff152e3f UD |
80 | # define USE_TSEARCH 1 |
81 | # include <search.h> | |
82 | ||
83 | /* This is a pointer to the root of the search tree with the known | |
84 | values. */ | |
85 | static void *known_values; | |
86 | ||
b17277cf UD |
87 | # define KNOWN_VALUE(Str) \ |
88 | ({ \ | |
a709dd43 UD |
89 | void *value = tfind (Str, &known_values, (__compar_fn_t) strcmp); \ |
90 | value != NULL ? *(char **) value : NULL; \ | |
b17277cf UD |
91 | }) |
92 | # define STORE_VALUE(Str) \ | |
a709dd43 | 93 | tsearch (Str, &known_values, (__compar_fn_t) strcmp) |
ff152e3f UD |
94 | |
95 | #else | |
96 | # undef USE_TSEARCH | |
97 | ||
98 | # define KNOWN_VALUE(Str) NULL | |
99 | # define STORE_VALUE(Str) do { } while (0) | |
100 | ||
101 | #endif | |
102 | ||
3e5f5557 | 103 | |
f0e44959 UD |
104 | /* If this variable is not a null pointer we allocated the current |
105 | environment. */ | |
106 | static char **last_environ; | |
107 | ||
108 | ||
de4a40d0 UD |
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 | |
114 | free the strings. */ | |
28f540f4 | 115 | int |
f63f2bfd JM |
116 | __add_to_environ (const char *name, const char *value, const char *combined, |
117 | int replace) | |
28f540f4 | 118 | { |
2e09a79a JM |
119 | char **ep; |
120 | size_t size; | |
03c1e456 PE |
121 | |
122 | /* Compute lengths before locking, so that the critical section is | |
123 | less of a performance bottleneck. VALLEN is needed only if | |
124 | COMBINED is null (unfortunately GCC is not smart enough to deduce | |
125 | this; see the #pragma at the start of this file). Testing | |
126 | COMBINED instead of VALUE causes setenv (..., NULL, ...) to dump | |
127 | core now instead of corrupting memory later. */ | |
196980f5 | 128 | const size_t namelen = strlen (name); |
03c1e456 PE |
129 | size_t vallen; |
130 | if (combined == NULL) | |
131 | vallen = strlen (value) + 1; | |
28f540f4 | 132 | |
9e0f4072 RM |
133 | LOCK; |
134 | ||
7195db12 UD |
135 | /* We have to get the pointer now that we have the lock and not earlier |
136 | since another thread might have created a new environment. */ | |
137 | ep = __environ; | |
138 | ||
28f540f4 | 139 | size = 0; |
96ff4937 | 140 | if (ep != NULL) |
b0772d3b | 141 | { |
96ff4937 | 142 | for (; *ep != NULL; ++ep) |
b0772d3b UD |
143 | if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=') |
144 | break; | |
145 | else | |
146 | ++size; | |
147 | } | |
196980f5 | 148 | |
3504e5a6 | 149 | if (ep == NULL || __builtin_expect (*ep == NULL, 1)) |
28f540f4 | 150 | { |
196980f5 | 151 | char **new_environ; |
86187531 | 152 | |
ff152e3f UD |
153 | /* We allocated this space; we can extend it. */ |
154 | new_environ = (char **) realloc (last_environ, | |
155 | (size + 2) * sizeof (char *)); | |
28f540f4 | 156 | if (new_environ == NULL) |
9e0f4072 RM |
157 | { |
158 | UNLOCK; | |
159 | return -1; | |
160 | } | |
1448f324 OB |
161 | |
162 | if (__environ != last_environ) | |
163 | memcpy ((char *) new_environ, (char *) __environ, | |
164 | size * sizeof (char *)); | |
165 | ||
f3d338c9 | 166 | new_environ[size] = NULL; |
28f540f4 | 167 | new_environ[size + 1] = NULL; |
f3d338c9 | 168 | ep = new_environ + size; |
28f540f4 | 169 | |
196980f5 | 170 | last_environ = __environ = new_environ; |
28f540f4 | 171 | } |
f3d338c9 | 172 | if (*ep == NULL || replace) |
28f540f4 | 173 | { |
cb37d842 | 174 | char *np; |
ff152e3f | 175 | |
de4a40d0 UD |
176 | /* Use the user string if given. */ |
177 | if (combined != NULL) | |
178 | np = (char *) combined; | |
179 | else | |
180 | { | |
c63bfa79 | 181 | const size_t varlen = namelen + 1 + vallen; |
ff152e3f | 182 | #ifdef USE_TSEARCH |
c63bfa79 UD |
183 | char *new_value; |
184 | int use_alloca = __libc_use_alloca (varlen); | |
185 | if (__builtin_expect (use_alloca, 1)) | |
186 | new_value = (char *) alloca (varlen); | |
187 | else | |
188 | { | |
189 | new_value = malloc (varlen); | |
190 | if (new_value == NULL) | |
191 | { | |
192 | UNLOCK; | |
193 | return -1; | |
194 | } | |
195 | } | |
ff152e3f | 196 | # ifdef _LIBC |
de4a40d0 UD |
197 | __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1), |
198 | value, vallen); | |
ff152e3f | 199 | # else |
de4a40d0 UD |
200 | memcpy (new_value, name, namelen); |
201 | new_value[namelen] = '='; | |
202 | memcpy (&new_value[namelen + 1], value, vallen); | |
ff152e3f UD |
203 | # endif |
204 | ||
de4a40d0 | 205 | np = KNOWN_VALUE (new_value); |
a1ffb40e | 206 | if (__glibc_likely (np == NULL)) |
de4a40d0 | 207 | #endif |
9e0f4072 | 208 | { |
c63bfa79 | 209 | #ifdef USE_TSEARCH |
a1ffb40e | 210 | if (__glibc_unlikely (! use_alloca)) |
c63bfa79 UD |
211 | np = new_value; |
212 | else | |
213 | #endif | |
de4a40d0 | 214 | { |
c63bfa79 | 215 | np = malloc (varlen); |
a1ffb40e | 216 | if (__glibc_unlikely (np == NULL)) |
c63bfa79 UD |
217 | { |
218 | UNLOCK; | |
219 | return -1; | |
220 | } | |
ff152e3f UD |
221 | |
222 | #ifdef USE_TSEARCH | |
c63bfa79 | 223 | memcpy (np, new_value, varlen); |
86187531 | 224 | #else |
c63bfa79 UD |
225 | memcpy (np, name, namelen); |
226 | np[namelen] = '='; | |
227 | memcpy (&np[namelen + 1], value, vallen); | |
86187531 | 228 | #endif |
c63bfa79 | 229 | } |
de4a40d0 UD |
230 | /* And remember the value. */ |
231 | STORE_VALUE (np); | |
232 | } | |
d5b1c5ed EB |
233 | #ifdef USE_TSEARCH |
234 | else | |
235 | { | |
236 | if (__glibc_unlikely (! use_alloca)) | |
237 | free (new_value); | |
238 | } | |
239 | #endif | |
28f540f4 | 240 | } |
cb37d842 | 241 | |
cb37d842 | 242 | *ep = np; |
28f540f4 RM |
243 | } |
244 | ||
9e0f4072 RM |
245 | UNLOCK; |
246 | ||
28f540f4 RM |
247 | return 0; |
248 | } | |
196980f5 | 249 | |
de4a40d0 | 250 | int |
9d46370c | 251 | setenv (const char *name, const char *value, int replace) |
de4a40d0 | 252 | { |
e17f8b61 RM |
253 | if (name == NULL || *name == '\0' || strchr (name, '=') != NULL) |
254 | { | |
255 | __set_errno (EINVAL); | |
256 | return -1; | |
257 | } | |
258 | ||
de4a40d0 UD |
259 | return __add_to_environ (name, value, NULL, replace); |
260 | } | |
261 | ||
61f9d0a3 | 262 | int |
9d46370c | 263 | unsetenv (const char *name) |
196980f5 | 264 | { |
7c5bb945 | 265 | size_t len; |
196980f5 RM |
266 | char **ep; |
267 | ||
61f9d0a3 UD |
268 | if (name == NULL || *name == '\0' || strchr (name, '=') != NULL) |
269 | { | |
270 | __set_errno (EINVAL); | |
271 | return -1; | |
272 | } | |
273 | ||
274 | len = strlen (name); | |
275 | ||
9e0f4072 RM |
276 | LOCK; |
277 | ||
de4a40d0 | 278 | ep = __environ; |
1fa7ae05 UD |
279 | if (ep != NULL) |
280 | while (*ep != NULL) | |
df1cf487 YR |
281 | { |
282 | if (!strncmp (*ep, name, len) && (*ep)[len] == '=') | |
283 | { | |
284 | /* Found it. Remove this pointer by moving later ones back. */ | |
285 | char **dp = ep; | |
286 | ||
287 | do | |
288 | dp[0] = dp[1]; | |
289 | while (*dp++); | |
290 | /* Continue the loop in case NAME appears again. */ | |
291 | } | |
292 | else | |
293 | ++ep; | |
294 | } | |
9e0f4072 RM |
295 | |
296 | UNLOCK; | |
61f9d0a3 UD |
297 | |
298 | return 0; | |
196980f5 | 299 | } |
f0e44959 UD |
300 | |
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. */ | |
304 | int | |
60d2f8f3 | 305 | clearenv (void) |
f0e44959 UD |
306 | { |
307 | LOCK; | |
308 | ||
309 | if (__environ == last_environ && __environ != NULL) | |
310 | { | |
de4a40d0 | 311 | /* We allocated this environment so we can free it. */ |
f0e44959 UD |
312 | free (__environ); |
313 | last_environ = NULL; | |
314 | } | |
315 | ||
316 | /* Clear the environment pointer removes the whole environment. */ | |
317 | __environ = NULL; | |
318 | ||
319 | UNLOCK; | |
320 | ||
321 | return 0; | |
322 | } | |
3e5f5557 | 323 | #ifdef _LIBC |
c877418f | 324 | libc_freeres_fn (free_mem) |
69071b2a UD |
325 | { |
326 | /* Remove all traces. */ | |
327 | clearenv (); | |
328 | ||
329 | /* Now remove the search tree. */ | |
330 | __tdestroy (known_values, free); | |
331 | known_values = NULL; | |
332 | } | |
69071b2a | 333 | |
ff152e3f UD |
334 | # undef setenv |
335 | # undef unsetenv | |
3e5f5557 | 336 | # undef clearenv |
ff152e3f UD |
337 | weak_alias (__setenv, setenv) |
338 | weak_alias (__unsetenv, unsetenv) | |
3e5f5557 UD |
339 | weak_alias (__clearenv, clearenv) |
340 | #endif |