libgfortran/intrinsics/env.c

   1 /* Implementation of the GETENV g77, and
   2    GET_ENVIRONMENT_VARIABLE F2003, intrinsics.
   3    Copyright (C) 2004 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 "config.h"
  33 #include <stdlib.h>
  34 #include <string.h>
  35 #include "libgfortran.h"
  36
  37
  38 /* GETENV (NAME, VALUE), g77 intrinsic for retrieving the value of
  39    an environment variable. The name of the variable is specified in
  40    NAME, and the result is stored into VALUE.  */
  41
  42 void PREFIX(getenv) (char *, char *, gfc_charlen_type, gfc_charlen_type);
  43 export_proto_np(PREFIX(getenv));
  44
  45 void
  46 PREFIX(getenv) (char * name, char * value, gfc_charlen_type name_len,
  47                 gfc_charlen_type value_len)
  48 {
  49   char *name_nt;
  50   char *res = NULL;
  51   int res_len;
  52
  53   if (name == NULL || value == NULL)
  54     runtime_error ("Both arguments to getenv are mandatory.");
  55
  56   if (value_len < 1 || name_len < 1)
  57     runtime_error ("Zero length string(s) passed to getenv.");
  58   else
  59     memset (value, ' ', value_len); /* Blank the string.  */
  60
  61   /* Trim trailing spaces from name.  */
  62   while (name_len > 0 && name[name_len - 1] == ' ')
  63     name_len--;
  64
  65   /* Make a null terminated copy of the string.  */
  66   name_nt = gfc_alloca (name_len + 1);
  67   memcpy (name_nt, name, name_len);
  68   name_nt[name_len] = '\0';
  69
  70   res = getenv(name_nt);
  71
  72   /* If res is NULL, it means that the environment variable didn't
  73      exist, so just return.  */
  74   if (res == NULL)
  75     return;
  76
  77   res_len = strlen(res);
  78   if (value_len < res_len)
  79     memcpy (value, res, value_len);
  80   else
  81     memcpy (value, res, res_len);
  82 }
  83
  84
  85 /* GET_ENVIRONMENT_VARIABLE (name, [value, length, status, trim_name])
  86    is a F2003 intrinsic for getting an environment variable.  */
  87
  88 /* Status codes specifyed by the standard. */
  89 #define GFC_SUCCESS 0
  90 #define GFC_VALUE_TOO_SHORT -1
  91 #define GFC_NAME_DOES_NOT_EXIST 1
  92
  93 /* This is also specified by the standard and means that the
  94    processor doesn't support environment variables.  At the moment,
  95    gfortran doesn't use it.  */
  96 #define GFC_NOT_SUPPORTED 2
  97
  98 /* Processor-specific failure code.  */
  99 #define GFC_FAILURE 42
 100
 101 extern void get_environment_variable_i4 (char *, char *, GFC_INTEGER_4 *,
 102                                          GFC_INTEGER_4 *, GFC_LOGICAL_4 *,
 103                                          gfc_charlen_type, gfc_charlen_type);
 104 iexport_proto(get_environment_variable_i4);
 105
 106 void
 107 get_environment_variable_i4 (char *name, char *value, GFC_INTEGER_4 *length,
 108                              GFC_INTEGER_4 *status, GFC_LOGICAL_4 *trim_name,
 109                              gfc_charlen_type name_len,
 110                              gfc_charlen_type value_len)
 111 {
 112   int stat = GFC_SUCCESS, res_len = 0;
 113   char *name_nt;
 114   char *res;
 115
 116   if (name == NULL)
 117     runtime_error ("Name is required for get_environment_variable.");
 118
 119   if (value == NULL && length == NULL && status == NULL && trim_name == NULL)
 120     return;
 121
 122   if (name_len < 1)
 123     runtime_error ("Zero-length string passed as name to "
 124                    "get_environment_variable.");
 125
 126   if (value != NULL)
 127     {
 128       if (value_len < 1)
 129         runtime_error ("Zero-length string passed as value to "
 130                        "get_environment_variable.");
 131       else
 132         memset (value, ' ', value_len); /* Blank the string.  */
 133     }
 134
 135   if ((!trim_name) || *trim_name)
 136     {
 137       /* Trim trailing spaces from name.  */
 138       while (name_len > 0 && name[name_len - 1] == ' ')
 139         name_len--;
 140     }
 141   /* Make a null terminated copy of the name.  */
 142   name_nt = gfc_alloca (name_len + 1);
 143   memcpy (name_nt, name, name_len);
 144   name_nt[name_len] = '\0';
 145
 146   res = getenv(name_nt);
 147
 148   if (res == NULL)
 149     stat = GFC_NAME_DOES_NOT_EXIST;
 150   else
 151     {
 152       res_len = strlen(res);
 153       if (value != NULL)
 154         {
 155           if (value_len < res_len)
 156             {
 157               memcpy (value, res, value_len);
 158               stat = GFC_VALUE_TOO_SHORT;
 159             }
 160           else
 161             memcpy (value, res, res_len);
 162         }
 163     }
 164
 165   if (status != NULL)
 166     *status = stat;
 167
 168   if (length != NULL)
 169     *length = res_len;
 170 }
 171 iexport(get_environment_variable_i4);
 172
 173
 174 /* INTEGER*8 wrapper for get_environment_variable.  */
 175
 176 extern void get_environment_variable_i8 (char *, char *, GFC_INTEGER_8 *,
 177                                          GFC_INTEGER_8 *, GFC_LOGICAL_8 *,
 178                                          gfc_charlen_type, gfc_charlen_type);
 179 export_proto(get_environment_variable_i8);
 180
 181 void
 182 get_environment_variable_i8 (char *name, char *value, GFC_INTEGER_8 *length,
 183                              GFC_INTEGER_8 *status, GFC_LOGICAL_8 *trim_name,
 184                              gfc_charlen_type name_len,
 185                              gfc_charlen_type value_len)
 186 {
 187   GFC_INTEGER_4 length4, status4;
 188   GFC_LOGICAL_4 trim_name4;
 189
 190   if (trim_name)
 191     trim_name4 = *trim_name;
 192
 193   get_environment_variable_i4 (name, value, &length4, &status4,
 194                                &trim_name4, name_len, value_len);
 195
 196   if (length)
 197     *length = length4;
 198
 199   if (status)
 200     *status = status4;
 201 }