login/utmpname.c

   1 /* Copyright (C) 1997, 2002, 2006 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Mark Kettenis <kettenis@phys.uva.nl>, 1997.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library 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 GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <bits/libc-lock.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <utmp.h>
  24
  25 #include "utmp-private.h"
  26
  27
  28 /* This is the default name.  */
  29 static const char default_file_name[] = _PATH_UTMP;
  30
  31 /* Current file name.  */
  32 const char *__libc_utmp_file_name = (const char *) default_file_name;
  33
  34 /* We have to use the lock in getutent_r.c.  */
  35 __libc_lock_define (extern, __libc_utmp_lock attribute_hidden)
  36
  37
  38 int
  39 __utmpname (const char *file)
  40 {
  41   int result = -1;
  42
  43   __libc_lock_lock (__libc_utmp_lock);
  44
  45   /* Close the old file.  */
  46   (*__libc_utmp_jump_table->endutent) ();
  47   __libc_utmp_jump_table = &__libc_utmp_unknown_functions;
  48
  49   if (strcmp (file, __libc_utmp_file_name) != 0)
  50     {
  51       if (strcmp (file, default_file_name) == 0)
  52         {
  53           free ((char *) __libc_utmp_file_name);
  54
  55           __libc_utmp_file_name = default_file_name;
  56         }
  57       else
  58         {
  59           char *file_name = __strdup (file);
  60           if (file_name == NULL)
  61             /* Out of memory.  */
  62             goto done;
  63
  64           if (__libc_utmp_file_name != default_file_name)
  65             free ((char *) __libc_utmp_file_name);
  66
  67           __libc_utmp_file_name = file_name;
  68         }
  69     }
  70
  71   result = 0;
  72
  73 done:
  74   __libc_lock_unlock (__libc_utmp_lock);
  75   return result;
  76 }
  77 weak_alias (__utmpname, utmpname)