libgfortran/intrinsics/env.c

   1 /* Implementation of the GETENV g77, and
   2    GET_ENVIRONMENT_VARIABLE F2003, intrinsics.
   3    Copyright (C) 2004, 2007 Free Software Foundation, Inc.
   4    Contributed by Janne Blomqvist.
   5
   6 This file is part of the GNU Fortran 95 runtime library (libgfortran).
   7
   8 Libgfortran is free software; you can redistribute it and/or
   9 modify it under the terms of the GNU General Public
  10 License as published by the Free Software Foundation; either
  11 version 2 of the License, or (at your option) any later version.
  12
  13 In addition to the permissions in the GNU General Public License, the
  14 Free Software Foundation gives you unlimited permission to link the
  15 compiled version of this file into combinations with other programs,
  16 and to distribute those combinations without any restriction coming
  17 from the use of this file.  (The General Public License restrictions
  18 do apply in other respects; for example, they cover modification of
  19 the file, and distribution when not linked into a combine
  20 executable.)
  21
  22 Libgfortran is distributed in the hope that it will be useful,
  23 but WITHOUT ANY WARRANTY; without even the implied warranty of
  24 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  25 GNU General Public License for more details.
  26
  27 You should have received a copy of the GNU General Public
  28 License along with libgfortran; see the file COPYING.  If not,
  29 write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  30 Boston, MA 02110-1301, USA.  */
  31
  32 #include "libgfortran.h"
  33 #include <stdlib.h>
  34 #include <string.h>
  35
  36
  37 /* GETENV (NAME, VALUE), g77 intrinsic for retrieving the value of
  38    an environment variable. The name of the variable is specified in
  39    NAME, and the result is stored into VALUE.  */
  40
  41 void PREFIX(getenv) (char *, char *, gfc_charlen_type, gfc_charlen_type);
  42 export_proto_np(PREFIX(getenv));
  43
  44 void
  45 PREFIX(getenv) (char * name, char * value, gfc_charlen_type name_len,
  46                 gfc_charlen_type value_len)
  47 {
  48   char *name_nt;
  49   char *res = NULL;
  50   int res_len;
  51
  52   if (name == NULL || value == NULL)
  53     runtime_error ("Both arguments to getenv are mandatory.");
  54
  55   if (value_len < 1 || name_len < 1)
  56     runtime_error ("Zero length string(s) passed to getenv.");
  57   else
  58     memset (value, ' ', value_len); /* Blank the string.  */
  59
  60   /* Trim trailing spaces from name.  */
  61   while (name_len > 0 && name[name_len - 1] == ' ')
  62     name_len--;
  63
  64   /* Make a null terminated copy of the string.  */
  65   name_nt = gfc_alloca (name_len + 1);
  66   memcpy (name_nt, name, name_len);
  67   name_nt[name_len] = '\0';
  68
  69   res = getenv(name_nt);
  70
  71   /* If res is NULL, it means that the environment variable didn't
  72      exist, so just return.  */
  73   if (res == NULL)
  74     return;
  75
  76   res_len = strlen(res);
  77   if (value_len < res_len)
  78     memcpy (value, res, value_len);
  79   else
  80     memcpy (value, res, res_len);
  81 }
  82
  83
  84 /* GET_ENVIRONMENT_VARIABLE (name, [value, length, status, trim_name])
  85    is a F2003 intrinsic for getting an environment variable.  */
  86
  87 /* Status codes specifyed by the standard. */
  88 #define GFC_SUCCESS 0
  89 #define GFC_VALUE_TOO_SHORT -1
  90 #define GFC_NAME_DOES_NOT_EXIST 1
  91
  92 /* This is also specified by the standard and means that the
  93    processor doesn't support environment variables.  At the moment,
  94    gfortran doesn't use it.  */
  95 #define GFC_NOT_SUPPORTED 2
  96
  97 /* Processor-specific failure code.  */
  98 #define GFC_FAILURE 42
  99
 100 extern void get_environment_variable_i4 (char *, char *, GFC_INTEGER_4 *,
 101                                          GFC_INTEGER_4 *, GFC_LOGICAL_4 *,
 102                                          gfc_charlen_type, gfc_charlen_type);
 103 iexport_proto(get_environment_variable_i4);
 104
 105 void
 106 get_environment_variable_i4 (char *name, char *value, GFC_INTEGER_4 *length,
 107                              GFC_INTEGER_4 *status, GFC_LOGICAL_4 *trim_name,
 108                              gfc_charlen_type name_len,
 109                              gfc_charlen_type value_len)
 110 {
 111   int stat = GFC_SUCCESS, res_len = 0;
 112   char *name_nt;
 113   char *res;
 114
 115   if (name == NULL)
 116     runtime_error ("Name is required for get_environment_variable.");
 117
 118   if (value == NULL && length == NULL && status == NULL && trim_name == NULL)
 119     return;
 120
 121   if (name_len < 1)
 122     runtime_error ("Zero-length string passed as name to "
 123                    "get_environment_variable.");
 124
 125   if (value != NULL)
 126     {
 127       if (value_len < 1)
 128         runtime_error ("Zero-length string passed as value to "
 129                        "get_environment_variable.");
 130       else
 131         memset (value, ' ', value_len); /* Blank the string.  */
 132     }
 133
 134   if ((!trim_name) || *trim_name)
 135     {
 136       /* Trim trailing spaces from name.  */
 137       while (name_len > 0 && name[name_len - 1] == ' ')
 138         name_len--;
 139     }
 140   /* Make a null terminated copy of the name.  */
 141   name_nt = gfc_alloca (name_len + 1);
 142   memcpy (name_nt, name, name_len);
 143   name_nt[name_len] = '\0';
 144
 145   res = getenv(name_nt);
 146
 147   if (res == NULL)
 148     stat = GFC_NAME_DOES_NOT_EXIST;
 149   else
 150     {
 151       res_len = strlen(res);
 152       if (value != NULL)
 153         {
 154           if (value_len < res_len)
 155             {
 156               memcpy (value, res, value_len);
 157               stat = GFC_VALUE_TOO_SHORT;
 158             }
 159           else
 160             memcpy (value, res, res_len);
 161         }
 162     }
 163
 164   if (status != NULL)
 165     *status = stat;
 166
 167   if (length != NULL)
 168     *length = res_len;
 169 }
 170 iexport(get_environment_variable_i4);
 171
 172
 173 /* INTEGER*8 wrapper for get_environment_variable.  */
 174
 175 extern void get_environment_variable_i8 (char *, char *, GFC_INTEGER_8 *,
 176                                          GFC_INTEGER_8 *, GFC_LOGICAL_8 *,
 177                                          gfc_charlen_type, gfc_charlen_type);
 178 export_proto(get_environment_variable_i8);
 179
 180 void
 181 get_environment_variable_i8 (char *name, char *value, GFC_INTEGER_8 *length,
 182                              GFC_INTEGER_8 *status, GFC_LOGICAL_8 *trim_name,
 183                              gfc_charlen_type name_len,
 184                              gfc_charlen_type value_len)
 185 {
 186   GFC_INTEGER_4 length4, status4;
 187   GFC_LOGICAL_4 trim_name4;
 188
 189   if (trim_name)
 190     trim_name4 = *trim_name;
 191
 192   get_environment_variable_i4 (name, value, &length4, &status4,
 193                                &trim_name4, name_len, value_len);
 194
 195   if (length)
 196     *length = length4;
 197
 198   if (status)
 199     *status = status4;
 200 }