libgfortran/intrinsics/env.c

   1 /* Implementation of the GETENV g77, and
   2    GET_ENVIRONMENT_VARIABLE F2003, intrinsics.
   3    Copyright (C) 2004-2013 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 <stdlib.h>
  29 #include <string.h>
  30
  31
  32 /* GETENV (NAME, VALUE), g77 intrinsic for retrieving the value of
  33    an environment variable. The name of the variable is specified in
  34    NAME, and the result is stored into VALUE.  */
  35
  36 void PREFIX(getenv) (char *, char *, gfc_charlen_type, gfc_charlen_type);
  37 export_proto_np(PREFIX(getenv));
  38
  39 void
  40 PREFIX(getenv) (char * name, char * value, gfc_charlen_type name_len,
  41                 gfc_charlen_type value_len)
  42 {
  43   char *name_nt;
  44   char *res = NULL;
  45   int res_len;
  46
  47   if (name == NULL || value == NULL)
  48     runtime_error ("Both arguments to getenv are mandatory.");
  49
  50   if (value_len < 1 || name_len < 1)
  51     runtime_error ("Zero length string(s) passed to getenv.");
  52   else
  53     memset (value, ' ', value_len); /* Blank the string.  */
  54
  55   /* Trim trailing spaces from name.  */
  56   while (name_len > 0 && name[name_len - 1] == ' ')
  57     name_len--;
  58
  59   /* Make a null terminated copy of the string.  */
  60   name_nt = gfc_alloca (name_len + 1);
  61   memcpy (name_nt, name, name_len);
  62   name_nt[name_len] = '\0';
  63
  64   res = getenv(name_nt);
  65
  66   /* If res is NULL, it means that the environment variable didn't
  67      exist, so just return.  */
  68   if (res == NULL)
  69     return;
  70
  71   res_len = strlen(res);
  72   if (value_len < res_len)
  73     memcpy (value, res, value_len);
  74   else
  75     memcpy (value, res, res_len);
  76 }
  77
  78
  79 /* GET_ENVIRONMENT_VARIABLE (name, [value, length, status, trim_name])
  80    is a F2003 intrinsic for getting an environment variable.  */
  81
  82 /* Status codes specifyed by the standard. */
  83 #define GFC_SUCCESS 0
  84 #define GFC_VALUE_TOO_SHORT -1
  85 #define GFC_NAME_DOES_NOT_EXIST 1
  86
  87 /* This is also specified by the standard and means that the
  88    processor doesn't support environment variables.  At the moment,
  89    gfortran doesn't use it.  */
  90 #define GFC_NOT_SUPPORTED 2
  91
  92 /* Processor-specific failure code.  */
  93 #define GFC_FAILURE 42
  94
  95 extern void get_environment_variable_i4 (char *, char *, GFC_INTEGER_4 *,
  96                                          GFC_INTEGER_4 *, GFC_LOGICAL_4 *,
  97                                          gfc_charlen_type, gfc_charlen_type);
  98 iexport_proto(get_environment_variable_i4);
  99
 100 void
 101 get_environment_variable_i4 (char *name, char *value, GFC_INTEGER_4 *length,
 102                              GFC_INTEGER_4 *status, GFC_LOGICAL_4 *trim_name,
 103                              gfc_charlen_type name_len,
 104                              gfc_charlen_type value_len)
 105 {
 106   int stat = GFC_SUCCESS, res_len = 0;
 107   char *name_nt;
 108   char *res;
 109
 110   if (name == NULL)
 111     runtime_error ("Name is required for get_environment_variable.");
 112
 113   if (value == NULL && length == NULL && status == NULL && trim_name == NULL)
 114     return;
 115
 116   if (name_len < 1)
 117     runtime_error ("Zero-length string passed as name to "
 118                    "get_environment_variable.");
 119
 120   if (value != NULL)
 121     {
 122       if (value_len < 1)
 123         runtime_error ("Zero-length string passed as value to "
 124                        "get_environment_variable.");
 125       else
 126         memset (value, ' ', value_len); /* Blank the string.  */
 127     }
 128
 129   if ((!trim_name) || *trim_name)
 130     {
 131       /* Trim trailing spaces from name.  */
 132       while (name_len > 0 && name[name_len - 1] == ' ')
 133         name_len--;
 134     }
 135   /* Make a null terminated copy of the name.  */
 136   name_nt = gfc_alloca (name_len + 1);
 137   memcpy (name_nt, name, name_len);
 138   name_nt[name_len] = '\0';
 139
 140   res = getenv(name_nt);
 141
 142   if (res == NULL)
 143     stat = GFC_NAME_DOES_NOT_EXIST;
 144   else
 145     {
 146       res_len = strlen(res);
 147       if (value != NULL)
 148         {
 149           if (value_len < res_len)
 150             {
 151               memcpy (value, res, value_len);
 152               stat = GFC_VALUE_TOO_SHORT;
 153             }
 154           else
 155             memcpy (value, res, res_len);
 156         }
 157     }
 158
 159   if (status != NULL)
 160     *status = stat;
 161
 162   if (length != NULL)
 163     *length = res_len;
 164 }
 165 iexport(get_environment_variable_i4);
 166
 167
 168 /* INTEGER*8 wrapper for get_environment_variable.  */
 169
 170 extern void get_environment_variable_i8 (char *, char *, GFC_INTEGER_8 *,
 171                                          GFC_INTEGER_8 *, GFC_LOGICAL_8 *,
 172                                          gfc_charlen_type, gfc_charlen_type);
 173 export_proto(get_environment_variable_i8);
 174
 175 void
 176 get_environment_variable_i8 (char *name, char *value, GFC_INTEGER_8 *length,
 177                              GFC_INTEGER_8 *status, GFC_LOGICAL_8 *trim_name,
 178                              gfc_charlen_type name_len,
 179                              gfc_charlen_type value_len)
 180 {
 181   GFC_INTEGER_4 length4, status4;
 182   GFC_LOGICAL_4 trim_name4;
 183
 184   if (trim_name)
 185     trim_name4 = *trim_name;
 186
 187   get_environment_variable_i4 (name, value, &length4, &status4,
 188                                trim_name ? &trim_name4 : NULL,
 189                                name_len, value_len);
 190
 191   if (length)
 192     *length = length4;
 193
 194   if (status)
 195     *status = status4;
 196 }