Mercurial > hg > octave-kai > gnulib-hg
annotate lib/setenv.c @ 4156:99ea86c79f44
Make it possibly to simply write: #include <alloca.h>.
| author | Bruno Haible <bruno@clisp.org> |
|---|---|
| date | Fri, 10 Jan 2003 21:06:49 +0000 |
| parents | d064e5107035 |
| children | e58a1c05a6ba |
| rev | line source |
|---|---|
|
4156
99ea86c79f44
Make it possibly to simply write: #include <alloca.h>.
Bruno Haible <bruno@clisp.org>
parents:
4080
diff
changeset
|
1 /* Copyright (C) 1992,1995-1999,2000-2003 Free Software Foundation, Inc. |
| 4080 | 2 This file is part of the GNU C Library. |
| 574 | 3 |
| 4080 | 4 The GNU C Library is free software; you can redistribute it and/or |
| 5 modify it under the terms of the GNU Library General Public License as | |
| 6 published by the Free Software Foundation; either version 2 of the | |
| 7 License, or (at your option) any later version. | |
| 574 | 8 |
| 4080 | 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 Library General Public License for more details. | |
| 574 | 13 |
| 4080 | 14 You should have received a copy of the GNU Library General Public |
| 15 License along with the GNU C Library; see the file COPYING.LIB. If not, | |
| 16 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
| 17 Boston, MA 02111-1307, USA. */ | |
| 574 | 18 |
| 4080 | 19 #if HAVE_CONFIG_H |
| 653 | 20 # include <config.h> |
| 574 | 21 #endif |
| 22 | |
|
4156
99ea86c79f44
Make it possibly to simply write: #include <alloca.h>.
Bruno Haible <bruno@clisp.org>
parents:
4080
diff
changeset
|
23 #include <alloca.h> |
| 4080 | 24 |
| 574 | 25 #include <errno.h> |
| 4080 | 26 #if !_LIBC |
| 27 # if !defined errno && !defined HAVE_ERRNO_DECL | |
| 28 extern int errno; | |
| 29 # endif | |
| 30 # define __set_errno(ev) ((errno) = (ev)) | |
| 31 #endif | |
| 574 | 32 |
| 33 #if _LIBC || HAVE_STDLIB_H | |
| 653 | 34 # include <stdlib.h> |
| 574 | 35 #endif |
| 36 #if _LIBC || HAVE_STRING_H | |
| 653 | 37 # include <string.h> |
| 574 | 38 #endif |
| 39 #if _LIBC || HAVE_UNISTD_H | |
| 653 | 40 # include <unistd.h> |
| 574 | 41 #endif |
| 42 | |
| 4080 | 43 /* For those losing systems which don't have 'alloca' we have to add |
| 44 some additional code emulating it. */ | |
| 45 #if _LIBC || HAVE_ALLOCA | |
| 46 # define freea(p) /* nothing */ | |
| 47 #else | |
| 48 # define alloca(n) malloc (n) | |
| 49 # define freea(p) free (p) | |
| 50 #endif | |
| 51 | |
| 52 #if !_LIBC | |
| 2718 | 53 # define __environ environ |
| 4080 | 54 # ifndef HAVE_ENVIRON_DECL |
| 55 extern char **environ; | |
| 56 # endif | |
| 57 #endif | |
| 58 | |
| 59 #if _LIBC | |
| 60 /* This lock protects against simultaneous modifications of `environ'. */ | |
| 61 # include <bits/libc-lock.h> | |
| 62 __libc_lock_define_initialized (static, envlock) | |
| 63 # define LOCK __libc_lock_lock (envlock) | |
| 64 # define UNLOCK __libc_lock_unlock (envlock) | |
| 65 #else | |
| 66 # define LOCK | |
| 67 # define UNLOCK | |
| 68 #endif | |
| 69 | |
| 70 /* In the GNU C library we must keep the namespace clean. */ | |
| 71 #ifdef _LIBC | |
| 72 # define setenv __setenv | |
| 73 # define clearenv __clearenv | |
| 74 # define tfind __tfind | |
| 75 # define tsearch __tsearch | |
| 574 | 76 #endif |
| 77 | |
| 4080 | 78 /* In the GNU C library implementation we try to be more clever and |
| 79 allow arbitrarily many changes of the environment given that the used | |
| 80 values are from a small set. Outside glibc this will eat up all | |
| 81 memory after a while. */ | |
| 82 #if defined _LIBC || (defined HAVE_SEARCH_H && defined HAVE_TSEARCH \ | |
| 83 && defined __GNUC__) | |
| 84 # define USE_TSEARCH 1 | |
| 85 # include <search.h> | |
| 86 typedef int (*compar_fn_t) (const void *, const void *); | |
| 87 | |
| 88 /* This is a pointer to the root of the search tree with the known | |
| 89 values. */ | |
| 90 static void *known_values; | |
| 91 | |
| 92 # define KNOWN_VALUE(Str) \ | |
| 93 ({ \ | |
| 94 void *value = tfind (Str, &known_values, (compar_fn_t) strcmp); \ | |
| 95 value != NULL ? *(char **) value : NULL; \ | |
| 96 }) | |
| 97 # define STORE_VALUE(Str) \ | |
| 98 tsearch (Str, &known_values, (compar_fn_t) strcmp) | |
| 99 | |
| 100 #else | |
| 101 # undef USE_TSEARCH | |
| 102 | |
| 103 # define KNOWN_VALUE(Str) NULL | |
| 104 # define STORE_VALUE(Str) do { } while (0) | |
| 105 | |
| 106 #endif | |
| 107 | |
| 108 | |
| 109 /* If this variable is not a null pointer we allocated the current | |
| 110 environment. */ | |
| 111 static char **last_environ; | |
| 112 | |
| 113 | |
| 114 /* This function is used by `setenv' and `putenv'. The difference between | |
| 115 the two functions is that for the former must create a new string which | |
| 116 is then placed in the environment, while the argument of `putenv' | |
| 117 must be used directly. This is all complicated by the fact that we try | |
| 118 to reuse values once generated for a `setenv' call since we can never | |
| 119 free the strings. */ | |
| 574 | 120 int |
| 4080 | 121 __add_to_environ (const char *name, const char *value, const char *combined, |
| 122 int replace) | |
| 574 | 123 { |
| 124 register char **ep; | |
| 125 register size_t size; | |
| 126 const size_t namelen = strlen (name); | |
| 4080 | 127 const size_t vallen = value != NULL ? strlen (value) + 1 : 0; |
| 128 | |
| 129 LOCK; | |
| 130 | |
| 131 /* We have to get the pointer now that we have the lock and not earlier | |
| 132 since another thread might have created a new environment. */ | |
| 133 ep = __environ; | |
| 574 | 134 |
| 135 size = 0; | |
| 4080 | 136 if (ep != NULL) |
| 137 { | |
| 138 for (; *ep != NULL; ++ep) | |
| 139 if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=') | |
| 140 break; | |
| 141 else | |
| 142 ++size; | |
| 143 } | |
| 574 | 144 |
| 4080 | 145 if (ep == NULL || *ep == NULL) |
| 574 | 146 { |
| 147 char **new_environ; | |
| 4080 | 148 #ifdef USE_TSEARCH |
| 149 char *new_value; | |
| 150 #endif | |
| 574 | 151 |
| 4080 | 152 /* We allocated this space; we can extend it. */ |
| 153 new_environ = | |
| 154 (char **) (last_environ == NULL | |
| 155 ? malloc ((size + 2) * sizeof (char *)) | |
| 156 : realloc (last_environ, (size + 2) * sizeof (char *))); | |
| 574 | 157 if (new_environ == NULL) |
| 4080 | 158 { |
| 159 UNLOCK; | |
| 160 return -1; | |
| 161 } | |
| 162 | |
| 163 /* If the whole entry is given add it. */ | |
| 164 if (combined != NULL) | |
| 165 /* We must not add the string to the search tree since it belongs | |
| 166 to the user. */ | |
| 167 new_environ[size] = (char *) combined; | |
| 168 else | |
| 169 { | |
| 170 /* See whether the value is already known. */ | |
| 171 #ifdef USE_TSEARCH | |
| 172 new_value = (char *) alloca (namelen + 1 + vallen); | |
| 173 # ifdef _LIBC | |
| 174 __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1), | |
| 175 value, vallen); | |
| 176 # else | |
| 177 memcpy (new_value, name, namelen); | |
| 178 new_value[namelen] = '='; | |
| 179 memcpy (&new_value[namelen + 1], value, vallen); | |
| 180 # endif | |
| 574 | 181 |
| 4080 | 182 new_environ[size] = KNOWN_VALUE (new_value); |
| 183 if (new_environ[size] == NULL) | |
| 184 #endif | |
| 185 { | |
| 186 new_environ[size] = (char *) malloc (namelen + 1 + vallen); | |
| 187 if (new_environ[size] == NULL) | |
| 188 { | |
| 189 #ifdef USE_TSEARCH | |
| 190 freea (new_value); | |
| 191 #endif | |
| 192 __set_errno (ENOMEM); | |
| 193 UNLOCK; | |
| 194 return -1; | |
| 195 } | |
| 196 | |
| 197 #ifdef USE_TSEARCH | |
| 198 memcpy (new_environ[size], new_value, namelen + 1 + vallen); | |
| 199 #else | |
| 200 memcpy (new_environ[size], name, namelen); | |
| 201 new_environ[size][namelen] = '='; | |
| 202 memcpy (&new_environ[size][namelen + 1], value, vallen); | |
| 203 #endif | |
| 204 /* And save the value now. We cannot do this when we remove | |
| 205 the string since then we cannot decide whether it is a | |
| 206 user string or not. */ | |
| 207 STORE_VALUE (new_environ[size]); | |
| 208 } | |
| 209 #ifdef USE_TSEARCH | |
| 210 freea (new_value); | |
| 211 #endif | |
| 574 | 212 } |
| 213 | |
| 214 if (__environ != last_environ) | |
| 215 memcpy ((char *) new_environ, (char *) __environ, | |
| 216 size * sizeof (char *)); | |
| 217 | |
| 218 new_environ[size + 1] = NULL; | |
| 219 | |
| 220 last_environ = __environ = new_environ; | |
| 221 } | |
| 222 else if (replace) | |
| 223 { | |
| 4080 | 224 char *np; |
| 225 | |
| 226 /* Use the user string if given. */ | |
| 227 if (combined != NULL) | |
| 228 np = (char *) combined; | |
| 229 else | |
| 574 | 230 { |
| 4080 | 231 #ifdef USE_TSEARCH |
| 232 char *new_value = alloca (namelen + 1 + vallen); | |
| 233 # ifdef _LIBC | |
| 234 __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1), | |
| 235 value, vallen); | |
| 236 # else | |
| 237 memcpy (new_value, name, namelen); | |
| 238 new_value[namelen] = '='; | |
| 239 memcpy (&new_value[namelen + 1], value, vallen); | |
| 240 # endif | |
| 241 | |
| 242 np = KNOWN_VALUE (new_value); | |
| 243 if (np == NULL) | |
| 244 #endif | |
| 245 { | |
| 246 np = malloc (namelen + 1 + vallen); | |
| 247 if (np == NULL) | |
| 248 { | |
| 249 #ifdef USE_TSEARCH | |
| 250 freea (new_value); | |
| 251 #endif | |
| 252 UNLOCK; | |
| 253 return -1; | |
| 254 } | |
| 255 | |
| 256 #ifdef USE_TSEARCH | |
| 257 memcpy (np, new_value, namelen + 1 + vallen); | |
| 258 #else | |
| 259 memcpy (np, name, namelen); | |
| 260 np[namelen] = '='; | |
| 261 memcpy (&np[namelen + 1], value, vallen); | |
| 262 #endif | |
| 263 /* And remember the value. */ | |
| 264 STORE_VALUE (np); | |
| 265 } | |
| 266 #ifdef USE_TSEARCH | |
| 267 freea (new_value); | |
| 268 #endif | |
| 574 | 269 } |
| 4080 | 270 |
| 271 *ep = np; | |
| 574 | 272 } |
| 273 | |
| 4080 | 274 UNLOCK; |
| 275 | |
| 574 | 276 return 0; |
| 277 } | |
| 278 | |
| 4080 | 279 int |
| 280 setenv (const char *name, const char *value, int replace) | |
| 281 { | |
| 282 return __add_to_environ (name, value, NULL, replace); | |
| 283 } | |
| 284 | |
| 285 /* The `clearenv' was planned to be added to POSIX.1 but probably | |
| 286 never made it. Nevertheless the POSIX.9 standard (POSIX bindings | |
| 287 for Fortran 77) requires this function. */ | |
| 288 int | |
| 289 clearenv () | |
| 574 | 290 { |
| 4080 | 291 LOCK; |
| 292 | |
| 293 if (__environ == last_environ && __environ != NULL) | |
| 294 { | |
| 295 /* We allocated this environment so we can free it. */ | |
| 296 free (__environ); | |
| 297 last_environ = NULL; | |
| 298 } | |
| 299 | |
| 300 /* Clear the environment pointer removes the whole environment. */ | |
| 301 __environ = NULL; | |
| 574 | 302 |
| 4080 | 303 UNLOCK; |
| 304 | |
| 305 return 0; | |
| 574 | 306 } |
| 4080 | 307 |
| 308 #ifdef _LIBC | |
| 309 static void | |
| 310 free_mem (void) | |
| 311 { | |
| 312 /* Remove all traces. */ | |
| 313 clearenv (); | |
| 314 | |
| 315 /* Now remove the search tree. */ | |
| 316 __tdestroy (known_values, free); | |
| 317 known_values = NULL; | |
| 318 } | |
| 319 text_set_element (__libc_subfreeres, free_mem); | |
| 320 | |
| 321 | |
| 322 # undef setenv | |
| 323 # undef clearenv | |
| 324 weak_alias (__setenv, setenv) | |
| 325 weak_alias (__clearenv, clearenv) | |
| 326 #endif |