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  1. /* Copyright (C) 1992, 1995, 1996, 1997, 2002, 2011 Free Software Foundation,
  2.    Inc.
  3.    This file based on setenv.c in the GNU C Library.
  4.  
  5.    The GNU C Library is free software; you can redistribute it and/or
  6.    modify it under the terms of the GNU Library General Public License as
  7.    published by the Free Software Foundation; either version 2 of the
  8.    License, or (at your option) any later version.
  9.  
  10.    The GNU C Library is distributed in the hope that it will be useful,
  11.    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12.    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13.    Library General Public License for more details.
  14.  
  15.    You should have received a copy of the GNU Library General Public
  16.    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17.    write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
  18.    Boston, MA 02110-1301, USA.  */
  19.  
  20.  
  21. /*
  22.  
  23. @deftypefn Supplemental int setenv (const char *@var{name}, @
  24.   const char *@var{value}, int @var{overwrite})
  25. @deftypefnx Supplemental void unsetenv (const char *@var{name})
  26.  
  27. @code{setenv} adds @var{name} to the environment with value
  28. @var{value}.  If the name was already present in the environment,
  29. the new value will be stored only if @var{overwrite} is nonzero.
  30. The companion @code{unsetenv} function removes @var{name} from the
  31. environment.  This implementation is not safe for multithreaded code.
  32.  
  33. @end deftypefn
  34.  
  35. */
  36.  
  37. #if HAVE_CONFIG_H
  38. # include <config.h>
  39. #endif
  40.  
  41. #define setenv libiberty_setenv
  42. #define unsetenv libiberty_unsetenv
  43.  
  44. #include "ansidecl.h"
  45. #include <sys/types.h> /* For `size_t' */
  46. #include <stdio.h>     /* For `NULL' */
  47.  
  48. #include <errno.h>
  49. #if !defined(errno) && !defined(HAVE_ERRNO_DECL)
  50. extern int errno;
  51. #endif
  52. #define __set_errno(ev) ((errno) = (ev))
  53.  
  54. #if HAVE_STDLIB_H
  55. # include <stdlib.h>
  56. #endif
  57. #if HAVE_STRING_H
  58. # include <string.h>
  59. #endif
  60. #if HAVE_UNISTD_H
  61. # include <unistd.h>
  62. #endif
  63.  
  64. #define __environ       environ
  65. #ifndef HAVE_ENVIRON_DECL
  66. extern char **environ;
  67. #endif
  68.  
  69. #undef setenv
  70. #undef unsetenv
  71.  
  72. /* LOCK and UNLOCK are defined as no-ops.  This makes the libiberty
  73.  * implementation MT-Unsafe. */
  74. #define LOCK
  75. #define UNLOCK
  76.  
  77. /* Below this point, it's verbatim code from the glibc-2.0 implementation */
  78.  
  79. /* If this variable is not a null pointer we allocated the current
  80.    environment.  */
  81. static char **last_environ;
  82.  
  83.  
  84. int
  85. setenv (const char *name, const char *value, int replace)
  86. {
  87.   register char **ep = 0;
  88.   register size_t size;
  89.   const size_t namelen = strlen (name);
  90.   const size_t vallen = strlen (value) + 1;
  91.  
  92.   LOCK;
  93.  
  94.   size = 0;
  95.   if (__environ != NULL)
  96.     {
  97.       for (ep = __environ; *ep != NULL; ++ep)
  98.         if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
  99.           break;
  100.         else
  101.           ++size;
  102.     }
  103.  
  104.   if (__environ == NULL || *ep == NULL)
  105.     {
  106.       char **new_environ;
  107.       if (__environ == last_environ && __environ != NULL)
  108.         /* We allocated this space; we can extend it.  */
  109.         new_environ = (char **) realloc (last_environ,
  110.                                          (size + 2) * sizeof (char *));
  111.       else
  112.         new_environ = (char **) malloc ((size + 2) * sizeof (char *));
  113.  
  114.       if (new_environ == NULL)
  115.         {
  116.           UNLOCK;
  117.           return -1;
  118.         }
  119.  
  120.       new_environ[size] = (char *) malloc (namelen + 1 + vallen);
  121.       if (new_environ[size] == NULL)
  122.         {
  123.           free ((char *) new_environ);
  124.           __set_errno (ENOMEM);
  125.           UNLOCK;
  126.           return -1;
  127.         }
  128.  
  129.       if (__environ != last_environ)
  130.         memcpy ((char *) new_environ, (char *) __environ,
  131.                 size * sizeof (char *));
  132.  
  133.       memcpy (new_environ[size], name, namelen);
  134.       new_environ[size][namelen] = '=';
  135.       memcpy (&new_environ[size][namelen + 1], value, vallen);
  136.  
  137.       new_environ[size + 1] = NULL;
  138.  
  139.       last_environ = __environ = new_environ;
  140.     }
  141.   else if (replace)
  142.     {
  143.       size_t len = strlen (*ep);
  144.       if (len + 1 < namelen + 1 + vallen)
  145.         {
  146.           /* The existing string is too short; malloc a new one.  */
  147.           char *new_string = (char *) malloc (namelen + 1 + vallen);
  148.           if (new_string == NULL)
  149.             {
  150.               UNLOCK;
  151.               return -1;
  152.             }
  153.           *ep = new_string;
  154.         }
  155.       memcpy (*ep, name, namelen);
  156.       (*ep)[namelen] = '=';
  157.       memcpy (&(*ep)[namelen + 1], value, vallen);
  158.     }
  159.  
  160.   UNLOCK;
  161.  
  162.   return 0;
  163. }
  164.  
  165. void
  166. unsetenv (const char *name)
  167. {
  168.   const size_t len = strlen (name);
  169.   char **ep;
  170.  
  171.   LOCK;
  172.  
  173.   for (ep = __environ; *ep; ++ep)
  174.     if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
  175.       {
  176.         /* Found it.  Remove this pointer by moving later ones back.  */
  177.         char **dp = ep;
  178.         do
  179.           dp[0] = dp[1];
  180.         while (*dp++);
  181.         /* Continue the loop in case NAME appears again.  */
  182.       }
  183.  
  184.   UNLOCK;
  185. }
  186.