u-tools/apps/tar/gnu/setenv.c

   1 /* -*- buffer-read-only: t -*- vi: set ro: */
   2 /* DO NOT EDIT! GENERATED AUTOMATICALLY! */
   3 /* Copyright (C) 1992, 1995-2003, 2005-2011 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    This program is free software: you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #if !_LIBC
  20 # include <config.h>
  21 #endif
  22
  23 /* Don't use __attribute__ __nonnull__ in this compilation unit.  Otherwise gcc
  24    optimizes away the name == NULL test below.  */
  25 #define _GL_ARG_NONNULL(params)
  26
  27 #include <alloca.h>
  28
  29 /* Specification.  */
  30 #include <stdlib.h>
  31
  32 #include <errno.h>
  33 #ifndef __set_errno
  34 # define __set_errno(ev) ((errno) = (ev))
  35 #endif
  36
  37 #include <string.h>
  38 #if _LIBC || HAVE_UNISTD_H
  39 # include <unistd.h>
  40 #endif
  41
  42 #if !_LIBC
  43 # include "malloca.h"
  44 #endif
  45
  46 #if _LIBC || !HAVE_SETENV
  47
  48 #if !_LIBC
  49 # define __environ      environ
  50 #endif
  51
  52 #if _LIBC
  53 /* This lock protects against simultaneous modifications of `environ'.  */
  54 # include <bits/libc-lock.h>
  55 __libc_lock_define_initialized (static, envlock)
  56 # define LOCK   __libc_lock_lock (envlock)
  57 # define UNLOCK __libc_lock_unlock (envlock)
  58 #else
  59 # define LOCK
  60 # define UNLOCK
  61 #endif
  62
  63 /* In the GNU C library we must keep the namespace clean.  */
  64 #ifdef _LIBC
  65 # define setenv __setenv
  66 # define clearenv __clearenv
  67 # define tfind __tfind
  68 # define tsearch __tsearch
  69 #else
  70 /* Use the system functions, not the gnulib overrides in this file.  */
  71 # undef malloc
  72 # undef realloc
  73 #endif
  74
  75 /* In the GNU C library implementation we try to be more clever and
  76    allow arbitrarily many changes of the environment given that the used
  77    values are from a small set.  Outside glibc this will eat up all
  78    memory after a while.  */
  79 #if defined _LIBC || (defined HAVE_SEARCH_H && defined HAVE_TSEARCH \
  80                       && defined __GNUC__)
  81 # define USE_TSEARCH    1
  82 # include <search.h>
  83 typedef int (*compar_fn_t) (const void *, const void *);
  84
  85 /* This is a pointer to the root of the search tree with the known
  86    values.  */
  87 static void *known_values;
  88
  89 # define KNOWN_VALUE(Str) \
  90   ({                                                                          \
  91     void *value = tfind (Str, &known_values, (compar_fn_t) strcmp);           \
  92     value != NULL ? *(char **) value : NULL;                                  \
  93   })
  94 # define STORE_VALUE(Str) \
  95   tsearch (Str, &known_values, (compar_fn_t) strcmp)
  96
  97 #else
  98 # undef USE_TSEARCH
  99
 100 # define KNOWN_VALUE(Str) NULL
 101 # define STORE_VALUE(Str) do { } while (0)
 102
 103 #endif
 104
 105
 106 /* If this variable is not a null pointer we allocated the current
 107    environment.  */
 108 static char **last_environ;
 109
 110
 111 /* This function is used by `setenv' and `putenv'.  The difference between
 112    the two functions is that for the former must create a new string which
 113    is then placed in the environment, while the argument of `putenv'
 114    must be used directly.  This is all complicated by the fact that we try
 115    to reuse values once generated for a `setenv' call since we can never
 116    free the strings.  */
 117 int
 118 __add_to_environ (const char *name, const char *value, const char *combined,
 119                   int replace)
 120 {
 121   char **ep;
 122   size_t size;
 123   const size_t namelen = strlen (name);
 124   const size_t vallen = value != NULL ? strlen (value) + 1 : 0;
 125
 126   LOCK;
 127
 128   /* We have to get the pointer now that we have the lock and not earlier
 129      since another thread might have created a new environment.  */
 130   ep = __environ;
 131
 132   size = 0;
 133   if (ep != NULL)
 134     {
 135       for (; *ep != NULL; ++ep)
 136         if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
 137           break;
 138         else
 139           ++size;
 140     }
 141
 142   if (ep == NULL || *ep == NULL)
 143     {
 144       char **new_environ;
 145 #ifdef USE_TSEARCH
 146       char *new_value;
 147 #endif
 148
 149       /* We allocated this space; we can extend it.  */
 150       new_environ =
 151         (char **) (last_environ == NULL
 152                    ? malloc ((size + 2) * sizeof (char *))
 153                    : realloc (last_environ, (size + 2) * sizeof (char *)));
 154       if (new_environ == NULL)
 155         {
 156           /* It's easier to set errno to ENOMEM than to rely on the
 157              'malloc-posix' and 'realloc-posix' gnulib modules.  */
 158           __set_errno (ENOMEM);
 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 # ifdef _LIBC
 173           new_value = (char *) alloca (namelen + 1 + vallen);
 174           __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
 175                      value, vallen);
 176 # else
 177           new_value = (char *) malloca (namelen + 1 + vallen);
 178           if (new_value == NULL)
 179             {
 180               __set_errno (ENOMEM);
 181               UNLOCK;
 182               return -1;
 183             }
 184           memcpy (new_value, name, namelen);
 185           new_value[namelen] = '=';
 186           memcpy (&new_value[namelen + 1], value, vallen);
 187 # endif
 188
 189           new_environ[size] = KNOWN_VALUE (new_value);
 190           if (new_environ[size] == NULL)
 191 #endif
 192             {
 193               new_environ[size] = (char *) malloc (namelen + 1 + vallen);
 194               if (new_environ[size] == NULL)
 195                 {
 196 #if defined USE_TSEARCH && !defined _LIBC
 197                   freea (new_value);
 198 #endif
 199                   __set_errno (ENOMEM);
 200                   UNLOCK;
 201                   return -1;
 202                 }
 203
 204 #ifdef USE_TSEARCH
 205               memcpy (new_environ[size], new_value, namelen + 1 + vallen);
 206 #else
 207               memcpy (new_environ[size], name, namelen);
 208               new_environ[size][namelen] = '=';
 209               memcpy (&new_environ[size][namelen + 1], value, vallen);
 210 #endif
 211               /* And save the value now.  We cannot do this when we remove
 212                  the string since then we cannot decide whether it is a
 213                  user string or not.  */
 214               STORE_VALUE (new_environ[size]);
 215             }
 216 #if defined USE_TSEARCH && !defined _LIBC
 217           freea (new_value);
 218 #endif
 219         }
 220
 221       if (__environ != last_environ)
 222         memcpy ((char *) new_environ, (char *) __environ,
 223                 size * sizeof (char *));
 224
 225       new_environ[size + 1] = NULL;
 226
 227       last_environ = __environ = new_environ;
 228     }
 229   else if (replace)
 230     {
 231       char *np;
 232
 233       /* Use the user string if given.  */
 234       if (combined != NULL)
 235         np = (char *) combined;
 236       else
 237         {
 238 #ifdef USE_TSEARCH
 239           char *new_value;
 240 # ifdef _LIBC
 241           new_value = alloca (namelen + 1 + vallen);
 242           __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
 243                      value, vallen);
 244 # else
 245           new_value = malloca (namelen + 1 + vallen);
 246           if (new_value == NULL)
 247             {
 248               __set_errno (ENOMEM);
 249               UNLOCK;
 250               return -1;
 251             }
 252           memcpy (new_value, name, namelen);
 253           new_value[namelen] = '=';
 254           memcpy (&new_value[namelen + 1], value, vallen);
 255 # endif
 256
 257           np = KNOWN_VALUE (new_value);
 258           if (np == NULL)
 259 #endif
 260             {
 261               np = (char *) malloc (namelen + 1 + vallen);
 262               if (np == NULL)
 263                 {
 264 #if defined USE_TSEARCH && !defined _LIBC
 265                   freea (new_value);
 266 #endif
 267                   __set_errno (ENOMEM);
 268                   UNLOCK;
 269                   return -1;
 270                 }
 271
 272 #ifdef USE_TSEARCH
 273               memcpy (np, new_value, namelen + 1 + vallen);
 274 #else
 275               memcpy (np, name, namelen);
 276               np[namelen] = '=';
 277               memcpy (&np[namelen + 1], value, vallen);
 278 #endif
 279               /* And remember the value.  */
 280               STORE_VALUE (np);
 281             }
 282 #if defined USE_TSEARCH && !defined _LIBC
 283           freea (new_value);
 284 #endif
 285         }
 286
 287       *ep = np;
 288     }
 289
 290   UNLOCK;
 291
 292   return 0;
 293 }
 294
 295 int
 296 setenv (const char *name, const char *value, int replace)
 297 {
 298   if (name == NULL || *name == '\0' || strchr (name, '=') != NULL)
 299     {
 300       __set_errno (EINVAL);
 301       return -1;
 302     }
 303
 304   return __add_to_environ (name, value, NULL, replace);
 305 }
 306
 307 /* The `clearenv' was planned to be added to POSIX.1 but probably
 308    never made it.  Nevertheless the POSIX.9 standard (POSIX bindings
 309    for Fortran 77) requires this function.  */
 310 int
 311 clearenv (void)
 312 {
 313   LOCK;
 314
 315   if (__environ == last_environ && __environ != NULL)
 316     {
 317       /* We allocated this environment so we can free it.  */
 318       free (__environ);
 319       last_environ = NULL;
 320     }
 321
 322   /* Clear the environment pointer removes the whole environment.  */
 323   __environ = NULL;
 324
 325   UNLOCK;
 326
 327   return 0;
 328 }
 329
 330 #ifdef _LIBC
 331 static void
 332 free_mem (void)
 333 {
 334   /* Remove all traces.  */
 335   clearenv ();
 336
 337   /* Now remove the search tree.  */
 338   __tdestroy (known_values, free);
 339   known_values = NULL;
 340 }
 341 text_set_element (__libc_subfreeres, free_mem);
 342
 343
 344 # undef setenv
 345 # undef clearenv
 346 weak_alias (__setenv, setenv)
 347 weak_alias (__clearenv, clearenv)
 348 #endif
 349
 350 #endif /* _LIBC || !HAVE_SETENV */
 351
 352 /* The rest of this file is called into use when replacing an existing
 353    but buggy setenv.  Known bugs include failure to diagnose invalid
 354    name, and consuming a leading '=' from value.  */
 355 #if HAVE_SETENV
 356
 357 # undef setenv
 358 # define STREQ(a, b) (strcmp (a, b) == 0)
 359
 360 int
 361 rpl_setenv (const char *name, const char *value, int replace)
 362 {
 363   int result;
 364   if (!name || !*name || strchr (name, '='))
 365     {
 366       errno = EINVAL;
 367       return -1;
 368     }
 369   /* Call the real setenv even if replace is 0, in case implementation
 370      has underlying data to update, such as when environ changes.  */
 371   result = setenv (name, value, replace);
 372   if (result == 0 && replace && *value == '=')
 373     {
 374       char *tmp = getenv (name);
 375       if (!STREQ (tmp, value))
 376         {
 377           int saved_errno;
 378           size_t len = strlen (value);
 379           tmp = malloca (len + 2);
 380           /* Since leading '=' is eaten, double it up.  */
 381           *tmp = '=';
 382           memcpy (tmp + 1, value, len + 1);
 383           result = setenv (name, tmp, replace);
 384           saved_errno = errno;
 385           freea (tmp);
 386           errno = saved_errno;
 387         }
 388     }
 389   return result;
 390 }
 391
 392 #endif /* HAVE_SETENV */