putenv.c File Reference

#include <precomp.h>

Include dependency graph for putenv.c:

Go to the source code of this file.

Functions
int	SetEnv (const wchar_t *option)
int	_putenv (const char *val)

Function Documentation

_putenv()

int _putenv

(

const char *

val

)

Definition at line 18 of file putenv.c.

{
   int size, result;
   wchar_t *woption;

   size = MultiByteToWideChar(CP_ACP, 0, val, -1, NULL, 0);
   woption = malloc(size* sizeof(wchar_t));
   if (woption == NULL)
      return -1;
   MultiByteToWideChar(CP_ACP, 0, val, -1, woption, size);
   result = SetEnv(woption);
   free(woption);
   return result;
}

SetEnv()

int SetEnv

(

const wchar_t *

option

)

Internal version of _wputenv and _putenv. It works duplicates the original envirnments created during initilization if needed to prevent having spurious pointers floating around. Then it updates the internal environment tables (_environ and _wenviron) and at last updates the OS environemnt.

Note that there can happen situation when the internal [_w]environ arrays will be updated, but the OS environment update will fail. In this case we don't undo the changes to the [_w]environ tables to comply with the Microsoft behaviour (and it's also much easier :-).

Definition at line 210 of file environ.c.

{
   wchar_t *epos, *name;
   wchar_t **wenvptr;
   wchar_t *woption;
   char *mboption;
   int remove, index, count, size, result = 0, found = 0;
   wchar_t **wnewenv;
   char **mbnewenv;

   if (option == NULL || (epos = wcschr(option, L'=')) == NULL)
      return -1;
   remove = (epos[1] == 0);

   /* Duplicate environment if needed. */
   if (_environ == __initenv)
   {
      if ((_environ = DuplicateEnvironment(_environ, 0)) == __initenv)
         return -1;
   }
   if (_wenviron == __winitenv)
   {
      if ((_wenviron = (wchar_t**)DuplicateEnvironment((char**)_wenviron, 1)) ==
          __winitenv)
         return -1;
   }

   /* Create a copy of the option name. */
   name = malloc((epos - option + 1) * sizeof(wchar_t));
   if (name == NULL)
      return -1;
   memcpy(name, option, (epos - option) * sizeof(wchar_t));
   name[epos - option] = 0;

   /* Find the option we're trying to modify. */
   for (index = 0, wenvptr = _wenviron; *wenvptr != NULL; wenvptr++, index++)
   {
      if (!_wcsnicmp(*wenvptr, option, epos - option))
      {
         found = 1;
         break;
      }
   }

   if (remove)
   {
      if (!found)
      {
         free(name);
         return 0;
      }

      /* Remove the option from wide character environment. */
      free(*wenvptr);
      for (count = index; *wenvptr != NULL; wenvptr++, count++)
         *wenvptr = *(wenvptr + 1);
      wnewenv = realloc(_wenviron, count * sizeof(wchar_t*));
      if (wnewenv != NULL)
         _wenviron = wnewenv;

      /* Remove the option from multibyte environment. We assume
       * the environments are in sync and the option is at the
       * same position. */
      free(_environ[index]);
      memmove(&_environ[index], &_environ[index+1], (count - index) * sizeof(char*));
      mbnewenv = realloc(_environ, count * sizeof(char*));
      if (mbnewenv != NULL)
         _environ = mbnewenv;

      result = SetEnvironmentVariableW(name, NULL) ? 0 : -1;
   }
   else
   {
      /* Make a copy of the option that we will store in the environment block. */
      woption = _wcsdup((wchar_t*)option);
      if (woption == NULL)
      {
         free(name);
         return -1;
      }

      /* Create a multibyte copy of the option. */
      size = WideCharToMultiByte(CP_ACP, 0, option, -1, NULL, 0, NULL, NULL);
      mboption = malloc(size);
      if (mboption == NULL)
      {
         free(name);
         free(woption);
         return -1;
      }
      WideCharToMultiByte(CP_ACP, 0, option, -1, mboption, size, NULL, NULL);

      if (found)
      {
         /* Replace the current entry. */
         free(*wenvptr);
         *wenvptr = woption;
         free(_environ[index]);
         _environ[index] = mboption;
      }
      else
      {
         /* Get the size of the original environment. */
         for (count = index; *wenvptr != NULL; wenvptr++, count++)
            ;

         /* Create a new entry. */
         if ((wnewenv = realloc(_wenviron, (count + 2) * sizeof(wchar_t*))) == NULL)
         {
            free(name);
            free(mboption);
            free(woption);
            return -1;
         }
         _wenviron = wnewenv;
         if ((mbnewenv = realloc(_environ, (count + 2) * sizeof(char*))) == NULL)
         {
            free(name);
            free(mboption);
            free(woption);
            return -1;
         }
         _environ = mbnewenv;

         /* Set the last entry to our option. */
         _wenviron[count] = woption;
         _environ[count] = mboption;
         _wenviron[count + 1] = NULL;
         _environ[count + 1] = NULL;
      }

      /* And finally update the OS environment. */
      result = SetEnvironmentVariableW(name, epos + 1) ? 0 : -1;
   }
   free(name);

   return result;
}

Referenced by _putenv().