posix/confstr.c

   1 /* Copyright (C) 1991, 1996, 1997, 2000 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <stddef.h>
  20 #include <errno.h>
  21 #include <unistd.h>
  22 #include <string.h>
  23 #include <confstr.h>
  24
  25 /* If BUF is not NULL and LEN > 0, fill in at most LEN - 1 bytes
  26    of BUF with the value corresponding to NAME and zero-terminate BUF.
  27    Return the number of bytes required to hold NAME's entire value.  */
  28 size_t
  29 confstr (name, buf, len)
  30      int name;
  31      char *buf;
  32      size_t len;
  33 {
  34   const char *string;
  35   size_t string_len;
  36
  37   switch (name)
  38     {
  39     case _CS_PATH:
  40       {
  41         static const char cs_path[] = CS_PATH;
  42         string = cs_path;
  43         string_len = sizeof (cs_path);
  44       }
  45       break;
  46
  47     case _CS_XBS5_ILP32_OFFBIG_CFLAGS:
  48     case _CS_LFS_CFLAGS:
  49 #if defined _XBS5_ILP32_OFF32 && !defined _XBS5_ILP32_OFFBIG
  50       /* Signal that we want the new ABI.  */
  51       {
  52         static const char file_offset[] = "-D_FILE_OFFSET_BITS=64";
  53         string = file_offset;
  54         string_len = sizeof (file_offset);
  55       }
  56       break;
  57 #endif
  58
  59     case _CS_LFS_LINTFLAGS:
  60     case _CS_LFS_LDFLAGS:
  61     case _CS_LFS_LIBS:
  62     case _CS_LFS64_CFLAGS:
  63     case _CS_LFS64_LINTFLAGS:
  64     case _CS_LFS64_LDFLAGS:
  65     case _CS_LFS64_LIBS:
  66
  67     case _CS_XBS5_ILP32_OFF32_CFLAGS:
  68     case _CS_XBS5_ILP32_OFF32_LDFLAGS:
  69     case _CS_XBS5_ILP32_OFF32_LIBS:
  70     case _CS_XBS5_ILP32_OFF32_LINTFLAGS:
  71     case _CS_XBS5_ILP32_OFFBIG_LDFLAGS:
  72     case _CS_XBS5_ILP32_OFFBIG_LIBS:
  73     case _CS_XBS5_ILP32_OFFBIG_LINTFLAGS:
  74     case _CS_XBS5_LP64_OFF64_CFLAGS:
  75     case _CS_XBS5_LP64_OFF64_LDFLAGS:
  76     case _CS_XBS5_LP64_OFF64_LIBS:
  77     case _CS_XBS5_LP64_OFF64_LINTFLAGS:
  78     case _CS_XBS5_LPBIG_OFFBIG_CFLAGS:
  79     case _CS_XBS5_LPBIG_OFFBIG_LDFLAGS:
  80     case _CS_XBS5_LPBIG_OFFBIG_LIBS:
  81     case _CS_XBS5_LPBIG_OFFBIG_LINTFLAGS:
  82       /* GNU libc does not require special actions to use LFS functions.  */
  83       string = "";
  84       string_len = 1;
  85       break;
  86
  87     default:
  88       __set_errno (EINVAL);
  89       return 0;
  90     }
  91
  92   if (len > 0 && buf != NULL)
  93     {
  94       if (string_len <= len)
  95         memcpy (buf, string, string_len);
  96       else
  97         {
  98           memcpy (buf, string, len - 1);
  99           buf[len - 1] = '\0';
 100         }
 101     }
 102   return string_len;
 103 }