release/src/router/libiconv/srclib/setenv.c

   1 /* Copyright (C) 1992, 1995-2003, 2005-2011 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 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 General Public License for more details.
  13
  14    You should have received a copy of the GNU 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 */