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 extern char *__findenv_locked(const char *, int *, char **);
  46 extern int __setenv_locked(const char *, const char *, int, int, char ***, struct owned_ptr *);
  47 extern void __unsetenv_locked(const char *, char **, struct owned_ptr *);
  48
  49 extern void __environ_lock(void);
  50 extern void __environ_unlock(void);
  51
  52 extern struct owned_ptr *__env_owned;
  53 extern int __init__env_owned_locked(int);
  54
  55 /*
  56  * _cthread_init_routine used to be called from crt1.o to initialize threads.
  57  * This is no longer needed, as initialization happens in dylib initializers,
  58  * but is provided to maintain backwards compatibility.  Normally, for 10.5
  59  * or greater, _cthread_init_routine does nothing.
  60  *
  61  * Before 10.5, the _start routine in crt1.o clobbers environ with the original
  62  * stack value, which effectively undoes any environment changes made in
  63  * initializers.  When LEGACY_CRT1_ENVIRON is defined, we replace the
  64  * do-nothing routine with one that attempts to restore the environ value.
  65  * But this only works if the setenv (and family) routines were used
  66  * exclusively, (no direct manipulation of environ).  Note that according to
  67  * SUSv3, direct manipulation of environ may result in undefined behavior in
  68  * setenv and family, so we don't support that (on less than 10.5).
  69  */
  70 #ifdef BUILDING_VARIANT
  71 #  ifdef LEGACY_CRT1_ENVIRON
  72 extern char **_saved_environ;
  73 #  endif /* LEGACY_CRT1_ENVIRON */
  74 #else /* !BUILDING_VARIANT */
  75 #  ifdef LEGACY_CRT1_ENVIRON
  76 __private_extern__ char **_saved_environ = NULL;
  77
  78 static int
  79 _legacy_crt1_environ(void)
  80 {
  81         if (_saved_environ) *_NSGetEnviron() = _saved_environ;
  82         return 0;
  83 }
  84 int (*_cthread_init_routine)(void) = _legacy_crt1_environ;
  85
  86 #  else /* !LEGACY_CRT1_ENVIRON */
  87 static int _do_nothing(void) { return 0; }
  88 int (*_cthread_init_routine)(void) = _do_nothing;
  89 #  endif /* !LEGACY_CRT1_ENVIRON */
  90
  91 __private_extern__ struct owned_ptr *__env_owned = NULL;
  92
  93 /*
  94  * The owned_ptr structure is a table of pointers that we own, and can
  95  * realloc/free as we choose.  table[0] is always NULL, so it is always
  96  * less that any real pointer.  "used" is the number of table entries in use
  97  * (including the initial NULL), while "size" is the allocated size of the
  98  * table (used to enlarge the size of the table when needed).
  99  */
 100 struct owned_ptr {
 101     const void **table;
 102     int used;
 103     int size;
 104 };
 105
 106 #define OWNED_PTR_INITIAL_SIZE  8
 107
 108 __private_extern__ int _owned_ptr_search(struct owned_ptr * __restrict, const void * __restrict, int * __restrict);
 109
 110 __private_extern__ void
 111 _owned_ptr_add(struct owned_ptr * __restrict owned, const void * __restrict ptr)
 112 {
 113         int index;
 114
 115         if (_owned_ptr_search(owned, ptr, &index) == 0) return; /* already there */
 116         if (owned->used >= owned->size) {
 117                 int new_size = 2 * owned->size;
 118                 const void **new_table = (const void **)realloc(owned->table,
 119                                          new_size * sizeof(const void *));
 120                 if (!new_table) {
 121                         /* no memory to enlarge the table, so just drop */
 122                         return;
 123                 }
 124                 owned->table = new_table;
 125                 owned->size = new_size;
 126         }
 127         memmove(owned->table + index + 2, owned->table + index + 1,
 128                 sizeof(void *) * (owned->used - index - 1));
 129         owned->table[index + 1] = ptr;
 130         owned->used++;
 131 }
 132
 133 __private_extern__ struct owned_ptr *
 134 _owned_ptr_alloc(void)
 135 {
 136         struct owned_ptr *owned;
 137
 138         owned = (struct owned_ptr *)malloc(sizeof(struct owned_ptr));
 139         if (!owned) return NULL;
 140         owned->table = (const void **)malloc(OWNED_PTR_INITIAL_SIZE *
 141                                              sizeof(const void *));
 142         if (!owned->table) {
 143                 int save = errno;
 144                 free(owned);
 145                 errno = save;
 146                 return NULL;
 147         }
 148         owned->table[0] = NULL;
 149         owned->used = 1;
 150         owned->size = OWNED_PTR_INITIAL_SIZE;
 151         return owned;
 152 }
 153
 154 __private_extern__ void
 155 _owned_ptr_delete(struct owned_ptr *owned, int index)
 156 {
 157         if (!index || index >= owned->used) return;
 158         memmove(owned->table + index, owned->table + index + 1,
 159                 sizeof(void *) * (owned->used - index - 1));
 160         owned->used--;
 161 }
 162
 163 __private_extern__ void
 164 _owned_ptr_free(struct owned_ptr *owned)
 165 {
 166         free(owned->table);
 167         free(owned);
 168 }
 169
 170 /*
 171  * Search owned->table for "ptr".  Zero is returned if found, non-zero means
 172  * not found.  If "result" is non-NULL, the found index is returned in it, or
 173  * if not found, the index of the immediate lower value (ptr can be inserted
 174  * after this index).
 175  */
 176 __private_extern__ int
 177 _owned_ptr_search(struct owned_ptr * __restrict owned, const void * __restrict ptr, int * __restrict result)
 178 {
 179         int low = 0;
 180         int high = owned->used - 1;
 181         int cur;
 182
 183         if (owned->table[high] < ptr) {
 184                 if (result) *result = high;
 185                 return -1;
 186         } else if (owned->table[high] == ptr) {
 187                 if (result) *result = high;
 188                 return 0;
 189         }
 190         while (high - low > 1) {
 191                 cur = (low + high) / 2;
 192                 if (ptr > owned->table[cur]) {
 193                         low = cur;
 194                 } else if (ptr < owned->table[cur]) {
 195                         high = cur;
 196                 } else {
 197                         /* match found */
 198                         if (result) *result = cur;
 199                         return 0;
 200                 }
 201         }
 202         /* no match found; *result will be the insert-after position */
 203         if (result) *result = low;
 204         return -1;
 205 }
 206
 207 /*
 208  * Initialize the process's __env_owned structure
 209  */
 210 __private_extern__ int
 211 __init__env_owned_locked(int should_set_errno)
 212 {
 213         int save;
 214
 215         if (__env_owned) return 0;
 216
 217         if (!should_set_errno)
 218                 save = errno;
 219         __env_owned = _owned_ptr_alloc();
 220         if (!__env_owned) {
 221                 if (!should_set_errno)
 222                         errno = save;
 223                 return -1;
 224         }
 225         return 0;
 226 }
 227
 228 /*
 229  * The copy flag may have 3 values:
 230  *  1 - make a copy of the name/value pair
 231  *  0 - take the name as a user-supplied name=value string
 232  * -1 - like 0, except we copy of the name=value string in name
 233  */
 234 __private_extern__ int
 235 __setenv_locked(name, value, rewrite, copy, environp, owned)
 236         const char *name;
 237         const char *value;
 238         int rewrite, copy;
 239         char ***environp;
 240         struct owned_ptr *owned;
 241 {
 242         char *c;
 243         int offset;
 244         int oindex;
 245
 246         if ((c = __findenv_locked(name, &offset, *environp))) { /* find if already exists */
 247                 char *e;
 248                 if (!rewrite)
 249                         return (0);
 250                 /*
 251                  * In UNIX03, we can overwrite only if we allocated the
 252                  * string.  Then we can realloc it if it is too small.
 253                  */
 254                 e = (*environp)[offset];
 255                 if (_owned_ptr_search(owned, e, &oindex) == 0) {
 256                         if (copy > 0) {
 257                                 size_t l_value = strlen(value);
 258                                 if (strlen(c) < l_value) {      /* old smaller; resize*/
 259                                         char *r;
 260                                         size_t len = c - e;
 261                                         if ((r = realloc(e, l_value + len + 1)) == NULL)
 262                                                 return (-1);
 263                                         if (r != e) {
 264                                                 (*environp)[offset] = r;
 265                                                 c = r + len;
 266                                                 _owned_ptr_delete(owned, oindex);
 267                                                 _owned_ptr_add(owned, r);
 268                                         }
 269                                 }
 270                                 while ( (*c++ = *value++) );
 271                                 return (0);
 272                         }
 273                         /* Free up the slot for later use (putenv) */
 274                         _owned_ptr_delete(owned, oindex);
 275                         free(e);
 276                 }
 277         } else {                                        /* create new slot */
 278                 int cnt;
 279                 char **p;
 280
 281                 for (p = *environp, cnt = 0; *p; ++p, ++cnt);
 282                 if (_owned_ptr_search(owned, *environp, &oindex) == 0) {        /* just increase size */
 283                         p = (char **)realloc((char *)*environp,
 284                             (size_t)(sizeof(char *) * (cnt + 2)));
 285                         if (!p)
 286                                 return (-1);
 287                         if (*environp != p) {
 288                                 _owned_ptr_delete(owned, oindex);
 289                                 _owned_ptr_add(owned, p);
 290                                 *environp = p;
 291                         }
 292                 }
 293                 else {                          /* get new space */
 294                                                 /* copy old entries into it */
 295                         p = malloc((size_t)(sizeof(char *) * (cnt + 2)));
 296                         if (!p)
 297                                 return (-1);
 298                         _owned_ptr_add(owned, p);
 299                         bcopy(*environp, p, cnt * sizeof(char *));
 300                         *environp = p;
 301                 }
 302                 (*environp)[cnt + 1] = NULL;
 303                 offset = cnt;
 304         }
 305         /* For non Unix03, or UnixO3 setenv(), we make a copy of the user's
 306          * strings.  For Unix03 putenv(), we put the string directly in
 307          * the environment. */
 308         if (copy > 0) {
 309                 for (c = (char *)name; *c && *c != '='; ++c);   /* no `=' in name */
 310                 if (!((*environp)[offset] =                     /* name + `=' + value */
 311                     malloc((size_t)((int)(c - name) + strlen(value) + 2))))
 312                         return (-1);
 313                 _owned_ptr_add(owned, (*environp)[offset]);
 314                 for (c = (*environp)[offset]; (*c = *name++) && *c != '='; ++c);
 315                 for (*c++ = '='; (*c++ = *value++); );
 316         } else {
 317                 /* the legacy behavior copies the string */
 318                 if (copy < 0) {
 319                         size_t len = strlen(name);
 320                         if((c = malloc(len + 1)) == NULL)
 321                                 return (-1);
 322                         _owned_ptr_add(owned, c);
 323                         memcpy(c, name, len + 1);
 324                         name = c;
 325                 }
 326                 (*environp)[offset] = (char *)name;
 327         }
 328         return (0);
 329 }
 330
 331 __private_extern__ void
 332 __unsetenv_locked(const char *name, char **environ, struct owned_ptr *owned)
 333 {
 334         char **p;
 335         int offset;
 336         int oindex;
 337
 338         while (__findenv_locked(name, &offset, environ)) { /* if set multiple times */
 339                 /* if we malloc-ed it, free it first */
 340                 if (_owned_ptr_search(owned, environ[offset], &oindex) == 0) {
 341                         _owned_ptr_delete(owned, oindex);
 342                         free(environ[offset]);
 343                 }
 344                 for (p = &environ[offset];; ++p)
 345                         if (!(*p = *(p + 1)))
 346                                 break;
 347         }
 348 }
 349
 350 /****************************************************************************/
 351 /*
 352  * _allocenvstate -- SPI that creates a new state (opaque)
 353  */
 354 void *
 355 _allocenvstate(void)
 356 {
 357         return _owned_ptr_alloc();
 358 }
 359
 360 /*
 361  * _copyenv -- SPI that copies a NULL-tereminated char * array in a newly
 362  * allocated buffer, compatible with the other SPI env routines.  If env
 363  * is NULL, a char * array composed of a single NULL is returned.  NULL
 364  * is returned on error.  (This isn't needed anymore, as __setenv_locked will
 365  * automatically make a copy.)
 366  */
 367 char **
 368 _copyenv(char **env)
 369 {
 370         char **p;
 371         int cnt = 1;
 372
 373         if (env)
 374                 for (p = env; *p; ++p, ++cnt);
 375         p = (char **)malloc((size_t)(sizeof(char *) * cnt));
 376         if (!p)
 377                 return (NULL);
 378         if (env)
 379                 bcopy(env, p, cnt * sizeof(char *));
 380         else
 381                 *p = NULL;
 382         return p;
 383 }
 384
 385 /*
 386  * _deallocenvstate -- SPI that frees all the memory associated with the state
 387  * and all allocated strings, including the environment array itself if it
 388  * was copied.
 389  */
 390 int
 391 _deallocenvstate(void *state)
 392 {
 393         struct owned_ptr *owned;
 394
 395         if (!(owned = (struct owned_ptr *)state) || owned == __env_owned) {
 396                 errno = EINVAL;
 397                 return -1;
 398         }
 399         _owned_ptr_free(owned);
 400         return 0;
 401 }
 402
 403 /*
 404  * setenvp -- SPI using an arbitrary pointer to string array and an env state,
 405  * created by _allocenvstate().  Initial checking is not done.
 406  *
 407  *      Set the value of the environmental variable "name" to be
 408  *      "value".  If rewrite is set, replace any current value.
 409  */
 410 int
 411 _setenvp(const char *name, const char *value, int rewrite, char ***envp, void *state)
 412 {
 413         __environ_lock();
 414         if (__init__env_owned_locked(1)) {
 415                 __environ_unlock();
 416                 return (-1);
 417         }
 418         int ret = __setenv_locked(name, value, rewrite, 1, envp,
 419                         (state ? (struct owned_ptr *)state : __env_owned));
 420         __environ_unlock();
 421         return ret;
 422 }
 423
 424 /*
 425  * unsetenv(name) -- SPI using an arbitrary pointer to string array and an env
 426  * state, created by _allocenvstate().  Initial checking is not done.
 427  *
 428  *      Delete environmental variable "name".
 429  */
 430 int
 431 _unsetenvp(const char *name, char ***envp, void *state)
 432 {
 433         __environ_lock();
 434         if (__init__env_owned_locked(1)) {
 435                 __environ_unlock();
 436                 return (-1);
 437         }
 438         __unsetenv_locked(name, *envp, (state ? (struct owned_ptr *)state : __env_owned));
 439         __environ_unlock();
 440         return 0;
 441 }
 442
 443 #endif /* !BUILD_VARIANT */
 444
 445 /*
 446  * setenv --
 447  *      Set the value of the environmental variable "name" to be
 448  *      "value".  If rewrite is set, replace any current value.
 449  */
 450 int
 451 setenv(name, value, rewrite)
 452         const char *name;
 453         const char *value;
 454         int rewrite;
 455 {
 456         int ret;
 457
 458         /* no null ptr or empty str */
 459         if(name == NULL || *name == 0) {
 460                 errno = EINVAL;
 461                 return (-1);
 462         }
 463
 464 #if __DARWIN_UNIX03
 465         /* no '=' in name */
 466         if (strchr(name, '=')) {
 467                 errno = EINVAL;
 468                 return (-1);
 469         }
 470 #endif /* __DARWIN_UNIX03 */
 471
 472         __environ_lock();
 473         if (__init__env_owned_locked(1)) {
 474                 __environ_unlock();
 475                 return (-1);
 476         }
 477         ret = __setenv_locked(name, value, rewrite, 1, _NSGetEnviron(), __env_owned);
 478 #ifdef LEGACY_CRT1_ENVIRON
 479         _saved_environ = *_NSGetEnviron();
 480 #endif /* !LEGACY_CRT1_ENVIRON */
 481         __environ_unlock();
 482
 483         return ret;
 484 }
 485
 486 static inline __attribute__((always_inline)) int
 487 _unsetenv(const char *name, int should_set_errno)
 488 {
 489         __environ_lock();
 490         if (__init__env_owned_locked(should_set_errno)) {
 491                 __environ_unlock();
 492                 return (-1);
 493         }
 494         __unsetenv_locked(name, *_NSGetEnviron(), __env_owned);
 495         __environ_unlock();
 496         return 0;
 497 }
 498
 499 /*
 500  * unsetenv(name) --
 501  *      Delete environmental variable "name".
 502  */
 503 #if __DARWIN_UNIX03
 504 int
 505 unsetenv(const char *name)
 506 {
 507         /* no null ptr or empty str */
 508         if(name == NULL || *name == 0) {
 509                 errno = EINVAL;
 510                 return (-1);
 511         }
 512
 513         /* no '=' in name */
 514         if (strchr(name, '=')) {
 515                 errno = EINVAL;
 516                 return (-1);
 517         }
 518         return _unsetenv(name, 1);
 519 }
 520 #else /* !__DARWIN_UNIX03 */
 521 void
 522 unsetenv(const char *name)
 523 {
 524         /* no null ptr or empty str */
 525         if(name == NULL || *name == 0)
 526                 return;
 527         _unsetenv(name, 0);
 528 }
 529 #endif /* __DARWIN_UNIX03 */