stdlib/FreeBSD/setenv.c

   1 /*
   2  * Copyright (c) 1987, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #if defined(LIBC_SCCS) && !defined(lint)
  31 static char sccsid[] = "@(#)setenv.c    8.1 (Berkeley) 6/4/93";
  32 #endif /* LIBC_SCCS and not lint */
  33 #include <sys/cdefs.h>
  34 __FBSDID("$FreeBSD: src/lib/libc/stdlib/setenv.c,v 1.14 2007/05/01 16:02:41 ache Exp $");
  35
  36 #include <stddef.h>
  37 #include <stdlib.h>
  38 #include <string.h>
  39 #include <crt_externs.h>
  40 #include <errno.h>
  41 #include <sys/types.h>
  42 #include <fcntl.h>
  43
  44 struct owned_ptr;
  45 __private_extern__ char *__findenv(const char *, int *, char **);
  46 __private_extern__ int __setenv(const char *, const char *, int, int, char ***, struct owned_ptr *);
  47 __private_extern__ void __unsetenv(const char *, char **, struct owned_ptr *);
  48
  49 __private_extern__ struct owned_ptr *__env_owned;
  50 __private_extern__ int __init__env_owned(int);
  51
  52 /*
  53  * _cthread_init_routine used to be called from crt1.o to initialize threads.
  54  * This is no longer needed, as initialization happens in dylib initializers,
  55  * but is provided to maintain backwards compatibility.  Normally, for 10.5
  56  * or greater, _cthread_init_routine does nothing.
  57  *
  58  * Before 10.5, the _start routine in crt1.o clobbers environ with the original
  59  * stack value, which effectively undoes any environment changes made in
  60  * initializers.  When LEGACY_CRT1_ENVIRON is defined, we replace the
  61  * do-nothing routine with one that attempts to restore the environ value.
  62  * But this only works if the setenv (and family) routines were used
  63  * exclusively, (no direct manipulation of environ).  Note that according to
  64  * SUSv3, direct manipulation of environ may result in undefined behavior in
  65  * setenv and family, so we don't support that (on less than 10.5).
  66  */
  67 #ifdef BUILDING_VARIANT
  68 #  ifdef LEGACY_CRT1_ENVIRON
  69 extern char **_saved_environ;
  70 #  endif /* LEGACY_CRT1_ENVIRON */
  71 #else /* !BUILDING_VARIANT */
  72 #  ifdef LEGACY_CRT1_ENVIRON
  73 __private_extern__ char **_saved_environ = NULL;
  74
  75 static int
  76 _legacy_crt1_environ(void)
  77 {
  78         if (_saved_environ) *_NSGetEnviron() = _saved_environ;
  79         return 0;
  80 }
  81 int (*_cthread_init_routine)(void) = _legacy_crt1_environ;
  82
  83 #  else /* !LEGACY_CRT1_ENVIRON */
  84 static int _do_nothing(void) { return 0; }
  85 int (*_cthread_init_routine)(void) = _do_nothing;
  86 #  endif /* !LEGACY_CRT1_ENVIRON */
  87
  88 __private_extern__ struct owned_ptr *__env_owned = NULL;
  89
  90 /*
  91  * The owned_ptr structure is a table of pointers that we own, and can
  92  * realloc/free as we choose.  table[0] is always NULL, so it is always
  93  * less that any real pointer.  "used" is the number of table entries in use
  94  * (including the initial NULL), while "size" is the allocated size of the
  95  * table (used to enlarge the size of the table when needed).
  96  */
  97 struct owned_ptr {
  98     const void **table;
  99     int used;
 100     int size;
 101 };
 102
 103 #define OWNED_PTR_INITIAL_SIZE  8
 104
 105 __private_extern__ int _owned_ptr_search(struct owned_ptr * __restrict, const void * __restrict, int * __restrict);
 106
 107 __private_extern__ void
 108 _owned_ptr_add(struct owned_ptr * __restrict owned, const void * __restrict ptr)
 109 {
 110         int index;
 111
 112         if (_owned_ptr_search(owned, ptr, &index) == 0) return; /* already there */
 113         if (owned->used >= owned->size) {
 114                 int new_size = 2 * owned->size;
 115                 const void **new_table = (const void **)realloc(owned->table,
 116                                          new_size * sizeof(const void *));
 117                 if (!new_table) {
 118                         /* no memory to enlarge the table, so just drop */
 119                         return;
 120                 }
 121                 owned->table = new_table;
 122                 owned->size = new_size;
 123         }
 124         memmove(owned->table + index + 2, owned->table + index + 1,
 125                 sizeof(void *) * (owned->used - index - 1));
 126         owned->table[index + 1] = ptr;
 127         owned->used++;
 128 }
 129
 130 __private_extern__ struct owned_ptr *
 131 _owned_ptr_alloc(void)
 132 {
 133         struct owned_ptr *owned;
 134
 135         owned = (struct owned_ptr *)malloc(sizeof(struct owned_ptr));
 136         if (!owned) return NULL;
 137         owned->table = (const void **)malloc(OWNED_PTR_INITIAL_SIZE *
 138                                              sizeof(const void *));
 139         if (!owned->table) {
 140                 int save = errno;
 141                 free(owned);
 142                 errno = save;
 143                 return NULL;
 144         }
 145         owned->table[0] = NULL;
 146         owned->used = 1;
 147         owned->size = OWNED_PTR_INITIAL_SIZE;
 148         return owned;
 149 }
 150
 151 __private_extern__ void
 152 _owned_ptr_delete(struct owned_ptr *owned, int index)
 153 {
 154         if (!index || index >= owned->used) return;
 155         memmove(owned->table + index, owned->table + index + 1,
 156                 sizeof(void *) * (owned->used - index - 1));
 157         owned->used--;
 158 }
 159
 160 __private_extern__ void
 161 _owned_ptr_free(struct owned_ptr *owned)
 162 {
 163         free(owned->table);
 164         free(owned);
 165 }
 166
 167 /*
 168  * Search owned->table for "ptr".  Zero is returned if found, non-zero means
 169  * not found.  If "result" is non-NULL, the found index is returned in it, or
 170  * if not found, the index of the immediate lower value (ptr can be inserted
 171  * after this index).
 172  */
 173 __private_extern__ int
 174 _owned_ptr_search(struct owned_ptr * __restrict owned, const void * __restrict ptr, int * __restrict result)
 175 {
 176         int low = 0;
 177         int high = owned->used - 1;
 178         int cur;
 179
 180         if (owned->table[high] < ptr) {
 181                 if (result) *result = high;
 182                 return -1;
 183         } else if (owned->table[high] == ptr) {
 184                 if (result) *result = high;
 185                 return 0;
 186         }
 187         while (high - low > 1) {
 188                 cur = (low + high) / 2;
 189                 if (ptr > owned->table[cur]) {
 190                         low = cur;
 191                 } else if (ptr < owned->table[cur]) {
 192                         high = cur;
 193                 } else {
 194                         /* match found */
 195                         if (result) *result = cur;
 196                         return 0;
 197                 }
 198         }
 199         /* no match found; *result will be the insert-after position */
 200         if (result) *result = low;
 201         return -1;
 202 }
 203
 204 /*
 205  * Initialize the process's __env_owned structure
 206  */
 207 __private_extern__ int
 208 __init__env_owned(int should_set_errno)
 209 {
 210         int save;
 211
 212         if (__env_owned) return 0;
 213
 214         if (!should_set_errno)
 215                 save = errno;
 216         __env_owned = _owned_ptr_alloc();
 217         if (!__env_owned) {
 218                 if (!should_set_errno)
 219                         errno = save;
 220                 return -1;
 221         }
 222         return 0;
 223 }
 224
 225 /*
 226  * The copy flag may have 3 values:
 227  *  1 - make a copy of the name/value pair
 228  *  0 - take the name as a user-supplied name=value string
 229  * -1 - like 0, except we copy of the name=value string in name
 230  */
 231 __private_extern__ int
 232 __setenv(name, value, rewrite, copy, environp, owned)
 233         const char *name;
 234         const char *value;
 235         int rewrite, copy;
 236         char ***environp;
 237         struct owned_ptr *owned;
 238 {
 239         char *c;
 240         int offset;
 241         int oindex;
 242
 243         if ((c = __findenv(name, &offset, *environp))) { /* find if already exists */
 244                 char *e;
 245                 if (!rewrite)
 246                         return (0);
 247                 /*
 248                  * In UNIX03, we can overwrite only if we allocated the
 249                  * string.  Then we can realloc it if it is too small.
 250                  */
 251                 e = (*environp)[offset];
 252                 if (_owned_ptr_search(owned, e, &oindex) == 0) {
 253                         if (copy > 0) {
 254                                 size_t l_value = strlen(value);
 255                                 if (strlen(c) < l_value) {      /* old smaller; resize*/
 256                                         char *r;
 257                                         size_t len = c - e;
 258                                         if ((r = realloc(e, l_value + len + 1)) == NULL)
 259                                                 return (-1);
 260                                         if (r != e) {
 261                                                 (*environp)[offset] = r;
 262                                                 c = r + len;
 263                                                 _owned_ptr_delete(owned, oindex);
 264                                                 _owned_ptr_add(owned, r);
 265                                         }
 266                                 }
 267                                 while ( (*c++ = *value++) );
 268                                 return (0);
 269                         }
 270                         /* Free up the slot for later use (putenv) */
 271                         _owned_ptr_delete(owned, oindex);
 272                         free(e);
 273                 }
 274         } else {                                        /* create new slot */
 275                 int cnt;
 276                 char **p;
 277
 278                 for (p = *environp, cnt = 0; *p; ++p, ++cnt);
 279                 if (_owned_ptr_search(owned, *environp, &oindex) == 0) {        /* just increase size */
 280                         p = (char **)realloc((char *)*environp,
 281                             (size_t)(sizeof(char *) * (cnt + 2)));
 282                         if (!p)
 283                                 return (-1);
 284                         if (*environp != p) {
 285                                 _owned_ptr_delete(owned, oindex);
 286                                 _owned_ptr_add(owned, p);
 287                                 *environp = p;
 288                         }
 289                 }
 290                 else {                          /* get new space */
 291                                                 /* copy old entries into it */
 292                         p = malloc((size_t)(sizeof(char *) * (cnt + 2)));
 293                         if (!p)
 294                                 return (-1);
 295                         _owned_ptr_add(owned, p);
 296                         bcopy(*environp, p, cnt * sizeof(char *));
 297                         *environp = p;
 298                 }
 299                 (*environp)[cnt + 1] = NULL;
 300                 offset = cnt;
 301         }
 302         /* For non Unix03, or UnixO3 setenv(), we make a copy of the user's
 303          * strings.  For Unix03 putenv(), we put the string directly in
 304          * the environment. */
 305         if (copy > 0) {
 306                 for (c = (char *)name; *c && *c != '='; ++c);   /* no `=' in name */
 307                 if (!((*environp)[offset] =                     /* name + `=' + value */
 308                     malloc((size_t)((int)(c - name) + strlen(value) + 2))))
 309                         return (-1);
 310                 _owned_ptr_add(owned, (*environp)[offset]);
 311                 for (c = (*environp)[offset]; (*c = *name++) && *c != '='; ++c);
 312                 for (*c++ = '='; (*c++ = *value++); );
 313         } else {
 314                 /* the legacy behavior copies the string */
 315                 if (copy < 0) {
 316                         size_t len = strlen(name);
 317                         if((c = malloc(len + 1)) == NULL)
 318                                 return (-1);
 319                         _owned_ptr_add(owned, c);
 320                         memcpy(c, name, len + 1);
 321                         name = c;
 322                 }
 323                 (*environp)[offset] = (char *)name;
 324         }
 325         return (0);
 326 }
 327
 328 __private_extern__ void
 329 __unsetenv(const char *name, char **environ, struct owned_ptr *owned)
 330 {
 331         char **p;
 332         int offset;
 333         int oindex;
 334
 335         while (__findenv(name, &offset, environ)) { /* if set multiple times */
 336                 /* if we malloc-ed it, free it first */
 337                 if (_owned_ptr_search(owned, environ[offset], &oindex) == 0) {
 338                         _owned_ptr_delete(owned, oindex);
 339                         free(environ[offset]);
 340                 }
 341                 for (p = &environ[offset];; ++p)
 342                         if (!(*p = *(p + 1)))
 343                                 break;
 344         }
 345 }
 346
 347 /****************************************************************************/
 348 /*
 349  * _allocenvstate -- SPI that creates a new state (opaque)
 350  */
 351 void *
 352 _allocenvstate(void)
 353 {
 354         return _owned_ptr_alloc();
 355 }
 356
 357 /*
 358  * _copyenv -- SPI that copies a NULL-tereminated char * array in a newly
 359  * allocated buffer, compatible with the other SPI env routines.  If env
 360  * is NULL, a char * array composed of a single NULL is returned.  NULL
 361  * is returned on error.  (This isn't needed anymore, as __setenv will
 362  * automatically make a copy.)
 363  */
 364 char **
 365 _copyenv(char **env)
 366 {
 367         char **p;
 368         int cnt = 1;
 369
 370         if (env)
 371                 for (p = env; *p; ++p, ++cnt);
 372         p = (char **)malloc((size_t)(sizeof(char *) * cnt));
 373         if (!p)
 374                 return (NULL);
 375         if (env)
 376                 bcopy(env, p, cnt * sizeof(char *));
 377         else
 378                 *p = NULL;
 379         return p;
 380 }
 381
 382 /*
 383  * _deallocenvstate -- SPI that frees all the memory associated with the state
 384  * and all allocated strings, including the environment array itself if it
 385  * was copied.
 386  */
 387 int
 388 _deallocenvstate(void *state)
 389 {
 390         struct owned_ptr *owned;
 391
 392         if (!(owned = (struct owned_ptr *)state) || owned == __env_owned) {
 393                 errno = EINVAL;
 394                 return -1;
 395         }
 396         _owned_ptr_free(owned);
 397         return 0;
 398 }
 399
 400 /*
 401  * setenvp -- SPI using an arbitrary pointer to string array and an env state,
 402  * created by _allocenvstate().  Initial checking is not done.
 403  *
 404  *      Set the value of the environmental variable "name" to be
 405  *      "value".  If rewrite is set, replace any current value.
 406  */
 407 int
 408 _setenvp(const char *name, const char *value, int rewrite, char ***envp, void *state)
 409 {
 410         if (__init__env_owned(1)) return (-1);
 411         return (__setenv(name, value, rewrite, 1, envp, (state ? (struct owned_ptr *)state : __env_owned)));
 412 }
 413
 414 /*
 415  * unsetenv(name) -- SPI using an arbitrary pointer to string array and an env
 416  * state, created by _allocenvstate().  Initial checking is not done.
 417  *
 418  *      Delete environmental variable "name".
 419  */
 420 int
 421 _unsetenvp(const char *name, char ***envp, void *state)
 422 {
 423         if (__init__env_owned(1)) return (-1);
 424         __unsetenv(name, *envp, (state ? (struct owned_ptr *)state : __env_owned));
 425         return 0;
 426 }
 427
 428 #endif /* !BUILD_VARIANT */
 429
 430 /*
 431  * setenv --
 432  *      Set the value of the environmental variable "name" to be
 433  *      "value".  If rewrite is set, replace any current value.
 434  */
 435 int
 436 setenv(name, value, rewrite)
 437         const char *name;
 438         const char *value;
 439         int rewrite;
 440 {
 441 #ifdef LEGACY_CRT1_ENVIRON
 442         int ret;
 443 #endif /* LEGACY_CRT1_ENVIRON */
 444
 445         /* no null ptr or empty str */
 446         if(name == NULL || *name == 0) {
 447                 errno = EINVAL;
 448                 return (-1);
 449         }
 450
 451 #if __DARWIN_UNIX03
 452         /* no '=' in name */
 453         if (strchr(name, '=')) {
 454                 errno = EINVAL;
 455                 return (-1);
 456         }
 457 #endif /* __DARWIN_UNIX03 */
 458
 459         if (*value == '=')                      /* no `=' in value */
 460                 ++value;
 461         if (__init__env_owned(1)) return (-1);
 462 #ifdef LEGACY_CRT1_ENVIRON
 463         ret = __setenv(name, value, rewrite, 1, _NSGetEnviron(), __env_owned);
 464         _saved_environ = *_NSGetEnviron();
 465         return ret;
 466 #else /* !LEGACY_CRT1_ENVIRON */
 467         return (__setenv(name, value, rewrite, 1, _NSGetEnviron(), __env_owned));
 468 #endif /* !LEGACY_CRT1_ENVIRON */
 469 }
 470
 471 /*
 472  * unsetenv(name) --
 473  *      Delete environmental variable "name".
 474  */
 475 #if __DARWIN_UNIX03
 476 int
 477 #else /* !__DARWIN_UNIX03 */
 478 void
 479 #endif /* __DARWIN_UNIX03 */
 480 unsetenv(name)
 481         const char *name;
 482 {
 483 #if __DARWIN_UNIX03
 484         /* no null ptr or empty str */
 485         if(name == NULL || *name == 0) {
 486                 errno = EINVAL;
 487                 return (-1);
 488         }
 489
 490         /* no '=' in name */
 491         if (strchr(name, '=')) {
 492                 errno = EINVAL;
 493                 return (-1);
 494         }
 495         if (__init__env_owned(1)) return (-1);
 496 #else /* !__DARWIN_UNIX03 */
 497         /* no null ptr or empty str */
 498         if(name == NULL || *name == 0)
 499                 return;
 500         if (__init__env_owned(0)) return;
 501 #endif /* __DARWIN_UNIX03 */
 502         __unsetenv(name, *_NSGetEnviron(), __env_owned);
 503 #if __DARWIN_UNIX03
 504         return 0;
 505 #endif /* __DARWIN_UNIX03 */
 506 }