usr/src/lib/libast/common/misc/getenv.c

   1 /***********************************************************************
   2 *                                                                      *
   3 *               This software is part of the ast package               *
   4 *          Copyright (c) 1985-2010 AT&T Intellectual Property          *
   5 *                      and is licensed under the                       *
   6 *                  Common Public License, Version 1.0                  *
   7 *                    by AT&T Intellectual Property                     *
   8 *                                                                      *
   9 *                A copy of the License is available at                 *
  10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
  11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
  12 *                                                                      *
  13 *              Information and Software Systems Research               *
  14 *                            AT&T Research                             *
  15 *                           Florham Park NJ                            *
  16 *                                                                      *
  17 *                 Glenn Fowler <gsf@research.att.com>                  *
  18 *                  David Korn <dgk@research.att.com>                   *
  19 *                   Phong Vo <kpv@research.att.com>                    *
  20 *                                                                      *
  21 ***********************************************************************/
  22 #pragma prototyped
  23
  24 #if _UWIN && __STDPP__
  25 __STDPP__directive pragma pp:hide getenv
  26 #endif
  27
  28 #include "intercepts.h"
  29
  30 #if _UWIN && __STDPP__
  31 __STDPP__directive pragma pp:nohide getenv
  32 #endif
  33
  34 /*
  35  * NOTE: the "intercepts" definition is here instead of astintercept.c because some
  36  *       static linkers miss lone references to "intercepts" without "astintercept()"
  37  * ALSO: { 0 } definition required by some dynamic linkers averse to common symbols
  38  * UWIN: no _ast_getenv macro map to maintain ast54 compatibility
  39  */
  40
  41 Intercepts_t    intercepts
  42 #if _BLD_3d
  43                 ;
  44 #else
  45                 = { 0 };
  46 #endif
  47
  48 #if _UWIN && !defined(getenv)
  49
  50 #include <windows.h>
  51
  52 extern char**   environ;
  53
  54 static char*
  55 default_getenv(const char* name)
  56 {
  57         register char**         av;
  58         register const char*    cp;
  59         register const char*    sp;
  60         register char           c0;
  61         register char           c1;
  62
  63         av = environ;
  64         if (!av || !name || !(c0 = *name))
  65                 return 0;
  66         if (!(c1 = *++name))
  67                 c1 = '=';
  68         while (cp = *av++)
  69         {
  70                 if (cp[0] != c0 || cp[1] != c1)
  71                         continue;
  72                 sp = name;
  73                 cp++;
  74                 while (*sp && *sp++ == *cp++);
  75                 if (*(sp-1) != *(cp-1))
  76                         continue;
  77                 if (*sp == 0 && *cp == '=')
  78                         return (char*)(cp+1);
  79         }
  80         return 0;
  81 }
  82
  83 #endif
  84
  85 /*
  86  * get name from the environment
  87  */
  88
  89 #if defined(__EXPORT__) && defined(getenv)
  90 #define extern  __EXPORT__
  91 #endif
  92
  93 extern char*
  94 getenv(const char* name)
  95 {
  96 #if _UWIN && !defined(getenv) /* for ast54 compatibility */
  97         HANDLE          dll;
  98
  99         static char*    (*posix_getenv)(const char*);
 100
 101         if (!posix_getenv)
 102         {
 103                 if (dll = GetModuleHandle("posix.dll"))
 104                         posix_getenv = (char*(*)(const char*))GetProcAddress(dll, "getenv");
 105                 if (!posix_getenv)
 106                         posix_getenv = default_getenv;
 107         }
 108         return intercepts.intercept_getenv ? (*intercepts.intercept_getenv)(name) : (*posix_getenv)(name);
 109 #else
 110 #undef  getenv
 111         return intercepts.intercept_getenv ? (*intercepts.intercept_getenv)(name) : getenv(name);
 112 #endif
 113 }