libgfortran/intrinsics/env.c

   1 /* Implementation of the GETENV g77, and
   2    GET_ENVIRONMENT_VARIABLE F2003, intrinsics.
   3    Copyright (C) 2004-2023 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 3 of the License, or (at your option) any later version.
  12
  13 Libgfortran is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 Under Section 7 of GPL version 3, you are granted additional
  19 permissions described in the GCC Runtime Library Exception, version
  20 3.1, as published by the Free Software Foundation.
  21
  22 You should have received a copy of the GNU General Public License and
  23 a copy of the GCC Runtime Library Exception along with this program;
  24 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  25 <http://www.gnu.org/licenses/>.  */
  26
  27 #include "libgfortran.h"
  28 #include <string.h>
  29
  30
  31 /* GETENV (NAME, VALUE), g77 intrinsic for retrieving the value of
  32    an environment variable. The name of the variable is specified in
  33    NAME, and the result is stored into VALUE.  */
  34
  35 void PREFIX(getenv) (char *, char *, gfc_charlen_type, gfc_charlen_type);
  36 export_proto_np(PREFIX(getenv));
  37
  38 void
  39 PREFIX(getenv) (char * name, char * value, gfc_charlen_type name_len,
  40                 gfc_charlen_type value_len)
  41 {
  42   char *name_nt;
  43   char *res = NULL;
  44
  45   if (name == NULL || value == NULL)
  46     runtime_error ("Both arguments to getenv are mandatory.");
  47
  48   if (value_len < 1 || name_len < 1)
  49     runtime_error ("Zero length string(s) passed to getenv.");
  50   else
  51     memset (value, ' ', value_len); /* Blank the string.  */
  52
  53   /* Make a null terminated copy of the string.  */
  54   name_nt = fc_strdup (name, name_len);
  55
  56   res = getenv(name_nt);
  57
  58   free (name_nt);
  59
  60   /* If res is NULL, it means that the environment variable didn't
  61      exist, so just return.  */
  62   if (res == NULL)
  63     return;
  64
  65   cf_strcpy (value, value_len, res);
  66 }
  67
  68
  69 /* GET_ENVIRONMENT_VARIABLE (name, [value, length, status, trim_name])
  70    is a F2003 intrinsic for getting an environment variable.  */
  71
  72 /* Status codes specifyed by the standard. */
  73 #define GFC_SUCCESS 0
  74 #define GFC_VALUE_TOO_SHORT -1
  75 #define GFC_NAME_DOES_NOT_EXIST 1
  76
  77 /* This is also specified by the standard and means that the
  78    processor doesn't support environment variables.  At the moment,
  79    gfortran doesn't use it.  */
  80 #define GFC_NOT_SUPPORTED 2
  81
  82 /* Processor-specific failure code.  */
  83 #define GFC_FAILURE 42
  84
  85 extern void get_environment_variable_i4 (char *, char *, GFC_INTEGER_4 *,
  86                                          GFC_INTEGER_4 *, GFC_LOGICAL_4 *,
  87                                          gfc_charlen_type, gfc_charlen_type);
  88 iexport_proto(get_environment_variable_i4);
  89
  90 void
  91 get_environment_variable_i4 (char *name, char *value, GFC_INTEGER_4 *length,
  92                              GFC_INTEGER_4 *status, GFC_LOGICAL_4 *trim_name,
  93                              gfc_charlen_type name_len,
  94                              gfc_charlen_type value_len)
  95 {
  96   int stat = GFC_SUCCESS;
  97   gfc_charlen_type res_len = 0;
  98   char *name_nt;
  99   char *res;
 100
 101   if (name == NULL)
 102     runtime_error ("Name is required for get_environment_variable.");
 103
 104   if (value == NULL && length == NULL && status == NULL && trim_name == NULL)
 105     return;
 106
 107   if (name_len < 1)
 108     runtime_error ("Zero-length string passed as name to "
 109                    "get_environment_variable.");
 110
 111   if (value != NULL)
 112     {
 113       if (value_len > 0)
 114         memset (value, ' ', value_len); /* Blank the string.  */
 115     }
 116
 117   if ((!trim_name) || *trim_name)
 118     name_nt = fc_strdup (name, name_len);
 119   else
 120     name_nt = fc_strdup_notrim (name, name_len);
 121
 122   res = getenv(name_nt);
 123
 124   free (name_nt);
 125
 126   if (res == NULL)
 127     stat = GFC_NAME_DOES_NOT_EXIST;
 128   else
 129     {
 130       res_len = strlen(res);
 131       if (value != NULL)
 132         {
 133           if (value_len < res_len)
 134             {
 135               memcpy (value, res, value_len);
 136               stat = GFC_VALUE_TOO_SHORT;
 137             }
 138           else if (res_len > 0)
 139             memcpy (value, res, res_len);
 140         }
 141     }
 142
 143   if (status != NULL)
 144     *status = stat;
 145
 146   if (length != NULL)
 147     *length = res_len;
 148 }
 149 iexport(get_environment_variable_i4);
 150
 151
 152 /* INTEGER*8 wrapper for get_environment_variable.  */
 153
 154 extern void get_environment_variable_i8 (char *, char *, GFC_INTEGER_8 *,
 155                                          GFC_INTEGER_8 *, GFC_LOGICAL_8 *,
 156                                          gfc_charlen_type, gfc_charlen_type);
 157 export_proto(get_environment_variable_i8);
 158
 159 void
 160 get_environment_variable_i8 (char *name, char *value, GFC_INTEGER_8 *length,
 161                              GFC_INTEGER_8 *status, GFC_LOGICAL_8 *trim_name,
 162                              gfc_charlen_type name_len,
 163                              gfc_charlen_type value_len)
 164 {
 165   GFC_INTEGER_4 length4, status4;
 166   GFC_LOGICAL_4 trim_name4;
 167
 168   if (trim_name)
 169     trim_name4 = *trim_name;
 170
 171   get_environment_variable_i4 (name, value, &length4, &status4,
 172                                trim_name ? &trim_name4 : NULL,
 173                                name_len, value_len);
 174
 175   if (length)
 176     *length = length4;
 177
 178   if (status)
 179     *status = status4;
 180 }