external/gpl2/xcvs/dist/lib/getlogin_r.c

   1 /* Provide a working getlogin_r for systems which lack it.
   2
   3    Copyright (C) 2005 Free Software Foundation, Inc.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2, or (at your option)
   8    any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software Foundation,
  17    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  18
  19 /* written by Paul Eggert and Derek Price */
  20
  21 #ifdef HAVE_CONFIG_H
  22 # include <config.h>
  23 #endif
  24
  25 #include "getlogin_r.h"
  26
  27 #include <errno.h>
  28 #include <string.h>
  29
  30 #if HAVE_UNISTD_H
  31 # include <unistd.h>
  32 #endif
  33
  34 #if !HAVE_DECL_GETLOGIN
  35 char *getlogin (void);
  36 #endif
  37
  38 /* See getlogin_r.h for documentation.  */
  39 int
  40 getlogin_r (char *name, size_t size)
  41 {
  42   char *n;
  43   size_t nlen;
  44
  45   errno = 0;
  46   n = getlogin ();
  47
  48   /* A system function like getlogin_r is never supposed to set errno
  49      to zero, so make sure errno is nonzero here.  ENOENT is a
  50      reasonable errno value if getlogin returns NULL.  */
  51   if (!errno)
  52     errno = ENOENT;
  53
  54   if (!n)
  55     return errno;
  56   nlen = strlen (n);
  57   if (size <= nlen)
  58     return ERANGE;
  59   memcpy (name, n, nlen + 1);
  60   return 0;
  61 }