compiler/stdc/getenv.c

   1 /*
   2     Copyright © 1995-2014, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     C99 function getenv().
   6 */
   7
   8 #include <proto/exec.h>
   9 #include <proto/dos.h>
  10
  11 #include <errno.h>
  12
  13 #include "__stdcio_intbase.h"
  14
  15 #define DEBUG 0
  16 #include <aros/debug.h>
  17
  18 /*****************************************************************************
  19
  20     NAME */
  21 #include <stdlib.h>
  22
  23         char *getenv (
  24
  25 /*  SYNOPSIS */
  26         const char *name)
  27
  28 /*  FUNCTION
  29         Get an environment variable.
  30
  31     INPUTS
  32         name - Name of the environment variable.
  33
  34     RESULT
  35         Pointer to the variable's value, or NULL on failure.
  36         When no memory is available errno will be set to ENOMEM.
  37
  38     NOTES
  39         The returned contents of the environment variable is cached per
  40         StdCIOBase. So the returned value is valid and does not change
  41         until a next call to getenv on the same StdCIOBase.
  42
  43     EXAMPLE
  44
  45     BUGS
  46
  47     SEE ALSO
  48
  49     INTERNALS
  50         Based on libnix getenv
  51
  52 ******************************************************************************/
  53 {
  54     struct StdCIOIntBase *StdCIOBase =
  55         (struct StdCIOIntBase *)__aros_getbase_StdCIOBase;
  56     char  c;
  57
  58     /*
  59       This will always return 0 if the var exists and EOF if it doesn't,
  60       then we'll be able to retrieve the var length with IoErr()
  61     */
  62     if (!GetVar((char *)name, &c, 1, GVF_BINARY_VAR))
  63     {
  64         LONG len = IoErr();
  65
  66         D(bug("[getenv] Variable found of size %d\n", size));
  67
  68         if (len + 1 > StdCIOBase->varsize)
  69         {
  70             if (StdCIOBase->envvar)
  71                 FreeMem(StdCIOBase->envvar, StdCIOBase->varsize);
  72
  73             StdCIOBase->envvar = AllocMem(len + 1, MEMF_ANY);
  74             if (StdCIOBase->envvar == NULL)
  75             {
  76                 StdCIOBase->varsize = 0;
  77                 errno = ENOMEM;
  78                 return NULL;
  79             }
  80             StdCIOBase->varsize = len + 1;
  81         }
  82
  83         /* This should not fail, unless someone stole our variable */
  84         /* FIXME: maybe this function should be atomic */
  85         GetVar((char *)name, StdCIOBase->envvar, StdCIOBase->varsize, GVF_BINARY_VAR);
  86
  87         D(bug("[getenv] Got value \"%s\"\n", StdCIOBase->envvar));
  88
  89         return (StdCIOBase->envvar);
  90     }
  91     else
  92     {
  93         D(bug("[getenv] Variable not found\n"));
  94
  95         return NULL;
  96     }
  97 } /* getenv */
  98