| 1 | /* Copyright (C) 1992, 1995-2003, 2005-2012 Free Software Foundation, Inc. |
| 2 | This file is part of the GNU C Library. |
| 3 | |
| 4 | This program is free software: you can redistribute it and/or modify |
| 5 | it under the terms of the GNU Lesser 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. |
| 8 | |
| 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 Lesser General Public License for more details. |
| 13 | |
| 14 | You should have received a copy of the GNU Lesser General Public License |
| 15 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 16 | |
| 17 | #if !_LIBC |
| 18 | # define _GL_USE_STDLIB_ALLOC 1 |
| 19 | # include <config.h> |
| 20 | #endif |
| 21 | |
| 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) |
| 25 | |
| 26 | #include <alloca.h> |
| 27 | |
| 28 | /* Specification. */ |
| 29 | #include <stdlib.h> |
| 30 | |
| 31 | #include <errno.h> |
| 32 | #ifndef __set_errno |
| 33 | # define __set_errno(ev) ((errno) = (ev)) |
| 34 | #endif |
| 35 | |
| 36 | #include <string.h> |
| 37 | #if _LIBC || HAVE_UNISTD_H |
| 38 | # include <unistd.h> |
| 39 | #endif |
| 40 | |
| 41 | #if !_LIBC |
| 42 | # include "malloca.h" |
| 43 | #endif |
| 44 | |
| 45 | #if _LIBC || !HAVE_SETENV |
| 46 | |
| 47 | #if !_LIBC |
| 48 | # define __environ environ |
| 49 | #endif |
| 50 | |
| 51 | #if _LIBC |
| 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) |
| 57 | #else |
| 58 | # define LOCK |
| 59 | # define UNLOCK |
| 60 | #endif |
| 61 | |
| 62 | /* In the GNU C library we must keep the namespace clean. */ |
| 63 | #ifdef _LIBC |
| 64 | # define setenv __setenv |
| 65 | # define clearenv __clearenv |
| 66 | # define tfind __tfind |
| 67 | # define tsearch __tsearch |
| 68 | #endif |
| 69 | |
| 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 \ |
| 75 | && defined __GNUC__) |
| 76 | # define USE_TSEARCH 1 |
| 77 | # include <search.h> |
| 78 | typedef int (*compar_fn_t) (const void *, const void *); |
| 79 | |
| 80 | /* This is a pointer to the root of the search tree with the known |
| 81 | values. */ |
| 82 | static void *known_values; |
| 83 | |
| 84 | # define KNOWN_VALUE(Str) \ |
| 85 | ({ \ |
| 86 | void *value = tfind (Str, &known_values, (compar_fn_t) strcmp); \ |
| 87 | value != NULL ? *(char **) value : NULL; \ |
| 88 | }) |
| 89 | # define STORE_VALUE(Str) \ |
| 90 | tsearch (Str, &known_values, (compar_fn_t) strcmp) |
| 91 | |
| 92 | #else |
| 93 | # undef USE_TSEARCH |
| 94 | |
| 95 | # define KNOWN_VALUE(Str) NULL |
| 96 | # define STORE_VALUE(Str) do { } while (0) |
| 97 | |
| 98 | #endif |
| 99 | |
| 100 | |
| 101 | /* If this variable is not a null pointer we allocated the current |
| 102 | environment. */ |
| 103 | static char **last_environ; |
| 104 | |
| 105 | |
| 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 |
| 111 | free the strings. */ |
| 112 | int |
| 113 | __add_to_environ (const char *name, const char *value, const char *combined, |
| 114 | int replace) |
| 115 | { |
| 116 | char **ep; |
| 117 | size_t size; |
| 118 | const size_t namelen = strlen (name); |
| 119 | const size_t vallen = value != NULL ? strlen (value) + 1 : 0; |
| 120 | |
| 121 | LOCK; |
| 122 | |
| 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. */ |
| 125 | ep = __environ; |
| 126 | |
| 127 | size = 0; |
| 128 | if (ep != NULL) |
| 129 | { |
| 130 | for (; *ep != NULL; ++ep) |
| 131 | if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=') |
| 132 | break; |
| 133 | else |
| 134 | ++size; |
| 135 | } |
| 136 | |
| 137 | if (ep == NULL || *ep == NULL) |
| 138 | { |
| 139 | char **new_environ; |
| 140 | #ifdef USE_TSEARCH |
| 141 | char *new_value; |
| 142 | #endif |
| 143 | |
| 144 | /* We allocated this space; we can extend it. */ |
| 145 | new_environ = |
| 146 | (char **) (last_environ == NULL |
| 147 | ? malloc ((size + 2) * sizeof (char *)) |
| 148 | : realloc (last_environ, (size + 2) * sizeof (char *))); |
| 149 | if (new_environ == NULL) |
| 150 | { |
| 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); |
| 154 | UNLOCK; |
| 155 | return -1; |
| 156 | } |
| 157 | |
| 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 |
| 161 | to the user. */ |
| 162 | new_environ[size] = (char *) combined; |
| 163 | else |
| 164 | { |
| 165 | /* See whether the value is already known. */ |
| 166 | #ifdef USE_TSEARCH |
| 167 | # ifdef _LIBC |
| 168 | new_value = (char *) alloca (namelen + 1 + vallen); |
| 169 | __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1), |
| 170 | value, vallen); |
| 171 | # else |
| 172 | new_value = (char *) malloca (namelen + 1 + vallen); |
| 173 | if (new_value == NULL) |
| 174 | { |
| 175 | __set_errno (ENOMEM); |
| 176 | UNLOCK; |
| 177 | return -1; |
| 178 | } |
| 179 | memcpy (new_value, name, namelen); |
| 180 | new_value[namelen] = '='; |
| 181 | memcpy (&new_value[namelen + 1], value, vallen); |
| 182 | # endif |
| 183 | |
| 184 | new_environ[size] = KNOWN_VALUE (new_value); |
| 185 | if (new_environ[size] == NULL) |
| 186 | #endif |
| 187 | { |
| 188 | new_environ[size] = (char *) malloc (namelen + 1 + vallen); |
| 189 | if (new_environ[size] == NULL) |
| 190 | { |
| 191 | #if defined USE_TSEARCH && !defined _LIBC |
| 192 | freea (new_value); |
| 193 | #endif |
| 194 | __set_errno (ENOMEM); |
| 195 | UNLOCK; |
| 196 | return -1; |
| 197 | } |
| 198 | |
| 199 | #ifdef USE_TSEARCH |
| 200 | memcpy (new_environ[size], new_value, namelen + 1 + vallen); |
| 201 | #else |
| 202 | memcpy (new_environ[size], name, namelen); |
| 203 | new_environ[size][namelen] = '='; |
| 204 | memcpy (&new_environ[size][namelen + 1], value, vallen); |
| 205 | #endif |
| 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]); |
| 210 | } |
| 211 | #if defined USE_TSEARCH && !defined _LIBC |
| 212 | freea (new_value); |
| 213 | #endif |
| 214 | } |
| 215 | |
| 216 | if (__environ != last_environ) |
| 217 | memcpy ((char *) new_environ, (char *) __environ, |
| 218 | size * sizeof (char *)); |
| 219 | |
| 220 | new_environ[size + 1] = NULL; |
| 221 | |
| 222 | last_environ = __environ = new_environ; |
| 223 | } |
| 224 | else if (replace) |
| 225 | { |
| 226 | char *np; |
| 227 | |
| 228 | /* Use the user string if given. */ |
| 229 | if (combined != NULL) |
| 230 | np = (char *) combined; |
| 231 | else |
| 232 | { |
| 233 | #ifdef USE_TSEARCH |
| 234 | char *new_value; |
| 235 | # ifdef _LIBC |
| 236 | new_value = alloca (namelen + 1 + vallen); |
| 237 | __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1), |
| 238 | value, vallen); |
| 239 | # else |
| 240 | new_value = malloca (namelen + 1 + vallen); |
| 241 | if (new_value == NULL) |
| 242 | { |
| 243 | __set_errno (ENOMEM); |
| 244 | UNLOCK; |
| 245 | return -1; |
| 246 | } |
| 247 | memcpy (new_value, name, namelen); |
| 248 | new_value[namelen] = '='; |
| 249 | memcpy (&new_value[namelen + 1], value, vallen); |
| 250 | # endif |
| 251 | |
| 252 | np = KNOWN_VALUE (new_value); |
| 253 | if (np == NULL) |
| 254 | #endif |
| 255 | { |
| 256 | np = (char *) malloc (namelen + 1 + vallen); |
| 257 | if (np == NULL) |
| 258 | { |
| 259 | #if defined USE_TSEARCH && !defined _LIBC |
| 260 | freea (new_value); |
| 261 | #endif |
| 262 | __set_errno (ENOMEM); |
| 263 | UNLOCK; |
| 264 | return -1; |
| 265 | } |
| 266 | |
| 267 | #ifdef USE_TSEARCH |
| 268 | memcpy (np, new_value, namelen + 1 + vallen); |
| 269 | #else |
| 270 | memcpy (np, name, namelen); |
| 271 | np[namelen] = '='; |
| 272 | memcpy (&np[namelen + 1], value, vallen); |
| 273 | #endif |
| 274 | /* And remember the value. */ |
| 275 | STORE_VALUE (np); |
| 276 | } |
| 277 | #if defined USE_TSEARCH && !defined _LIBC |
| 278 | freea (new_value); |
| 279 | #endif |
| 280 | } |
| 281 | |
| 282 | *ep = np; |
| 283 | } |
| 284 | |
| 285 | UNLOCK; |
| 286 | |
| 287 | return 0; |
| 288 | } |
| 289 | |
| 290 | int |
| 291 | setenv (const char *name, const char *value, int replace) |
| 292 | { |
| 293 | if (name == NULL || *name == '\0' || strchr (name, '=') != NULL) |
| 294 | { |
| 295 | __set_errno (EINVAL); |
| 296 | return -1; |
| 297 | } |
| 298 | |
| 299 | return __add_to_environ (name, value, NULL, replace); |
| 300 | } |
| 301 | |
| 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. */ |
| 305 | int |
| 306 | clearenv (void) |
| 307 | { |
| 308 | LOCK; |
| 309 | |
| 310 | if (__environ == last_environ && __environ != NULL) |
| 311 | { |
| 312 | /* We allocated this environment so we can free it. */ |
| 313 | free (__environ); |
| 314 | last_environ = NULL; |
| 315 | } |
| 316 | |
| 317 | /* Clear the environment pointer removes the whole environment. */ |
| 318 | __environ = NULL; |
| 319 | |
| 320 | UNLOCK; |
| 321 | |
| 322 | return 0; |
| 323 | } |
| 324 | |
| 325 | #ifdef _LIBC |
| 326 | static void |
| 327 | free_mem (void) |
| 328 | { |
| 329 | /* Remove all traces. */ |
| 330 | clearenv (); |
| 331 | |
| 332 | /* Now remove the search tree. */ |
| 333 | __tdestroy (known_values, free); |
| 334 | known_values = NULL; |
| 335 | } |
| 336 | text_set_element (__libc_subfreeres, free_mem); |
| 337 | |
| 338 | |
| 339 | # undef setenv |
| 340 | # undef clearenv |
| 341 | weak_alias (__setenv, setenv) |
| 342 | weak_alias (__clearenv, clearenv) |
| 343 | #endif |
| 344 | |
| 345 | #endif /* _LIBC || !HAVE_SETENV */ |
| 346 | |
| 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. */ |
| 350 | #if HAVE_SETENV |
| 351 | |
| 352 | # undef setenv |
| 353 | # if !HAVE_DECL_SETENV |
| 354 | extern int setenv (const char *, const char *, int); |
| 355 | # endif |
| 356 | # define STREQ(a, b) (strcmp (a, b) == 0) |
| 357 | |
| 358 | int |
| 359 | rpl_setenv (const char *name, const char *value, int replace) |
| 360 | { |
| 361 | int result; |
| 362 | if (!name || !*name || strchr (name, '=')) |
| 363 | { |
| 364 | errno = EINVAL; |
| 365 | return -1; |
| 366 | } |
| 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 == '=') |
| 371 | { |
| 372 | char *tmp = getenv (name); |
| 373 | if (!STREQ (tmp, value)) |
| 374 | { |
| 375 | int saved_errno; |
| 376 | size_t len = strlen (value); |
| 377 | tmp = malloca (len + 2); |
| 378 | /* Since leading '=' is eaten, double it up. */ |
| 379 | *tmp = '='; |
| 380 | memcpy (tmp + 1, value, len + 1); |
| 381 | result = setenv (name, tmp, replace); |
| 382 | saved_errno = errno; |
| 383 | freea (tmp); |
| 384 | errno = saved_errno; |
| 385 | } |
| 386 | } |
| 387 | return result; |
| 388 | } |
| 389 | |
| 390 | #endif /* HAVE_SETENV */ |