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 <sys/stat.h>
  31
  32 #include "utmp-private.h"
  33
  34
  35 /* The various backends we have.  */
  36 static int __setutent_unknown (int reset);
  37 static int __getutent_r_unknown (struct utmp *buffer, struct utmp **result);
  38 static struct utmp *__pututline_unknown (const struct utmp *data);
  39 static void __endutent_unknown (void);
  40
  41
  42 /* We have three jump tables: unknown, db, or file.  */
  43 static struct utfuncs unknown_functions =
  44 {
  45   __setutent_unknown,
  46   __getutent_r_unknown,
  47   NULL,
  48   NULL,
  49   __pututline_unknown,
  50   __endutent_unknown,
  51   NULL
  52 };
  53
  54 /* Currently selected backend.  */
  55 struct utfuncs *__libc_utmp_jump_table = &unknown_functions;
  56
  57 /* The tables from the services.  */
  58 extern struct utfuncs __libc_utmp_db_functions;
  59 extern struct utfuncs __libc_utmp_file_functions;
  60
  61
  62 /* We need to protect the opening of the file.  */
  63 __libc_lock_define_initialized (, __libc_utmp_lock)
  64
  65 void
  66 __setutent (void)
  67 {
  68   __libc_lock_lock (__libc_utmp_lock);
  69
  70   (void) (*__libc_utmp_jump_table->setutent) (1);
  71
  72   __libc_lock_unlock (__libc_utmp_lock);
  73 }
  74 weak_alias (__setutent, setutent)
  75
  76
  77 static int
  78 __setutent_unknown (int reset)
  79 {
  80   /* We have to test whether it is still not decided which backend to use.  */
  81   assert (__libc_utmp_jump_table == &unknown_functions);
  82
  83   /* See whether utmp db file exists.  */
  84   if ((*__libc_utmp_db_functions.setutent) (reset))
  85     __libc_utmp_jump_table = &__libc_utmp_db_functions;
  86   else
  87     {
  88       /* Either the db file does not exist or we have other
  89          problems.  So use the normal file.  */
  90       (*__libc_utmp_file_functions.setutent) (reset);
  91       __libc_utmp_jump_table = &__libc_utmp_file_functions;
  92     }
  93
  94   return 0;
  95 }
  96
  97
  98 void
  99 __endutent (void)
 100 {
 101   __libc_lock_lock (__libc_utmp_lock);
 102
 103   (*__libc_utmp_jump_table->endutent) ();
 104
 105   __libc_lock_unlock (__libc_utmp_lock);
 106 }
 107 weak_alias (__endutent, endutent)
 108
 109
 110 static void
 111 __endutent_unknown (void)
 112 {
 113   /* Huh, how do we came here?  Nothing to do.  */
 114 }
 115
 116
 117 int
 118 __getutent_r (struct utmp *buffer, struct utmp **result)
 119 {
 120   int retval;
 121
 122   __libc_lock_lock (__libc_utmp_lock);
 123
 124   retval = (*__libc_utmp_jump_table->getutent_r) (buffer, result);
 125
 126   __libc_lock_unlock (__libc_utmp_lock);
 127
 128   return retval;
 129 }
 130 weak_alias (__getutent_r, getutent_r)
 131
 132
 133 static int
 134 __getutent_r_unknown (struct utmp *buffer, struct utmp **result)
 135 {
 136   /* It is not yet initialized.  */
 137   __setutent_unknown (0);
 138
 139   return (*__libc_utmp_jump_table->getutent_r) (buffer, result);
 140 }
 141
 142
 143 struct utmp *
 144 __pututline (const struct utmp *data)
 145 {
 146   struct utmp *buffer;
 147
 148   __libc_lock_lock (__libc_utmp_lock);
 149
 150   buffer = (*__libc_utmp_jump_table->pututline) (data);
 151
 152   __libc_lock_unlock (__libc_utmp_lock);
 153
 154   return buffer;
 155 }
 156 weak_alias (__pututline, pututline)
 157
 158
 159 static struct utmp *
 160 __pututline_unknown (const struct utmp *data)
 161 {
 162   /* It is not yet initialized.  */
 163   __setutent_unknown (0);
 164
 165   return (*__libc_utmp_jump_table->pututline) (data);
 166 }
 167
 168
 169 int
 170 __utmpname (const char *file)
 171 {
 172   int result = -1;
 173
 174   __libc_lock_lock (__libc_utmp_lock);
 175
 176   /* Close the old file.  */
 177   (*__libc_utmp_jump_table->endutent) ();
 178
 179   /* Store new names.  */
 180   if ((*__libc_utmp_file_functions.utmpname) (file) == 0
 181       && !(*__libc_utmp_db_functions.utmpname) (file) == 0)
 182     {
 183       /* Try to find out whether we are supposed to work with a db
 184          file or not.  Do this by looking for the extension ".db".  */
 185       const char *ext = strrchr (file, '.');
 186
 187       if (ext != NULL && strcmp (ext, ".db") == 0)
 188         __libc_utmp_jump_table = &__libc_utmp_db_functions;
 189       else
 190         __libc_utmp_jump_table = &unknown_functions;
 191
 192       result = 0;
 193     }
 194
 195   __libc_lock_unlock (__libc_utmp_lock);
 196
 197   return result;
 198 }
 199 weak_alias (__utmpname, utmpname)