login/getutent_r.c

   1 /* Copyright (C) 1996 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@cygnus.com>
   4    and Paul Janzen <pcj@primenet.com>, 1996.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Library General Public License as
   8    published by the Free Software Foundation; either version 2 of the
   9    License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Library General Public License for more details.
  15
  16    You should have received a copy of the GNU Library General Public
  17    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  18    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include <assert.h>
  22 #include <db.h>
  23 #include <fcntl.h>
  24 #include <libc-lock.h>
  25 #include <limits.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <utmp.h>
  30 #include <gnu/lib-names.h>
  31 #include <sys/stat.h>
  32
  33 #include "utmp-private.h"
  34 #include "../elf/link.h"
  35
  36
  37 /* The various backends we have.  */
  38 static int __setutent_unknown (int reset);
  39 static int __getutent_r_unknown (struct utmp *buffer, struct utmp **result);
  40 static void __pututline_unknown (const struct utmp *data);
  41 static void __endutent_unknown (void);
  42
  43
  44 /* We have three jump tables: unknown, db, or file.  */
  45 static struct utfuncs unknown_functions =
  46 {
  47   __setutent_unknown,
  48   __getutent_r_unknown,
  49   NULL,
  50   NULL,
  51   __pututline_unknown,
  52   __endutent_unknown,
  53   NULL
  54 };
  55
  56 /* Currently selected backend.  */
  57 struct utfuncs *__libc_utmp_jump_table = &unknown_functions;
  58
  59 /* The tables from the services.  */
  60 extern struct utfuncs __libc_utmp_db_functions;
  61 extern struct utfuncs __libc_utmp_file_functions;
  62
  63
  64 /* We need to protect the opening of the file.  */
  65 __libc_lock_define_initialized (, __libc_utmp_lock)
  66
  67 void
  68 __setutent (void)
  69 {
  70   __libc_lock_lock (__libc_utmp_lock);
  71
  72   (void) (*__libc_utmp_jump_table->setutent) (1);
  73
  74   __libc_lock_unlock (__libc_utmp_lock);
  75 }
  76 weak_alias (__setutent, setutent)
  77
  78
  79 static int
  80 __setutent_unknown (int reset)
  81 {
  82   /* We have to test whether it is still not decided which backend to use.  */
  83   assert (__libc_utmp_jump_table == &unknown_functions);
  84
  85   /* See whether utmp db file exists.  */
  86   if ((*__libc_utmp_db_functions.setutent) (reset))
  87     __libc_utmp_jump_table = &__libc_utmp_db_functions;
  88   else
  89     {
  90       /* Either the db file does not exist or we have other
  91          problems.  So use the normal file.  */
  92       (*__libc_utmp_file_functions.setutent) (reset);
  93       __libc_utmp_jump_table = &__libc_utmp_file_functions;
  94     }
  95
  96   return 0;
  97 }
  98
  99
 100 void
 101 __endutent (void)
 102 {
 103   __libc_lock_lock (__libc_utmp_lock);
 104
 105   (*__libc_utmp_jump_table->endutent) ();
 106
 107   __libc_lock_unlock (__libc_utmp_lock);
 108 }
 109 weak_alias (__endutent, endutent)
 110
 111
 112 static void
 113 __endutent_unknown (void)
 114 {
 115   /* Huh, how do we came here?  Nothing to do.  */
 116 }
 117
 118
 119 int
 120 __getutent_r (struct utmp *buffer, struct utmp **result)
 121 {
 122   int retval;
 123
 124   __libc_lock_lock (__libc_utmp_lock);
 125
 126   retval = (*__libc_utmp_jump_table->getutent_r) (buffer, result);
 127
 128   __libc_lock_unlock (__libc_utmp_lock);
 129
 130   return retval;
 131 }
 132 weak_alias (__getutent_r, getutent_r)
 133
 134
 135 static int
 136 __getutent_r_unknown (struct utmp *buffer, struct utmp **result)
 137 {
 138   /* It is not yet initialized.  */
 139   __setutent_unknown (0);
 140
 141   return (*__libc_utmp_jump_table->getutent_r) (buffer, result);
 142 }
 143
 144
 145 void
 146 __pututline (const struct utmp *data)
 147 {
 148   __libc_lock_lock (__libc_utmp_lock);
 149
 150   (*__libc_utmp_jump_table->pututline) (data);
 151
 152   __libc_lock_unlock (__libc_utmp_lock);
 153 }
 154
 155
 156 static void
 157 __pututline_unknown (const struct utmp *data)
 158 {
 159   /* It is not yet initialized.  */
 160   __setutent_unknown (0);
 161
 162   (*__libc_utmp_jump_table->pututline) (data);
 163 }
 164
 165
 166 int
 167 __utmpname (const char *file)
 168 {
 169   int result = -1;
 170
 171   __libc_lock_lock (__libc_utmp_lock);
 172
 173   /* Close the old file.  */
 174   (*__libc_utmp_jump_table->endutent) ();
 175
 176   /* Store new names.  */
 177   if ((*__libc_utmp_file_functions.utmpname) (file) == 0
 178       && !(*__libc_utmp_db_functions.utmpname) (file) == 0)
 179     {
 180       /* Try to find out whether we are supposed to work with a db
 181          file or not.  Do this by looking for the extension ".db".  */
 182       const char *ext = strrchr (file, '.');
 183
 184       if (ext != NULL && strcmp (ext, ".db") == 0)
 185         __libc_utmp_jump_table = &__libc_utmp_db_functions;
 186       else
 187         __libc_utmp_jump_table = &unknown_functions;
 188
 189       result = 0;
 190     }
 191
 192   __libc_lock_unlock (__libc_utmp_lock);
 193
 194   return result;
 195 }
 196 weak_alias (__utmpname, utmpname)