login/getutid_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>, 1996.
   4
   5 The GNU C Library is free software; you can redistribute it and/or
   6 modify it under the terms of the GNU Library General Public License as
   7 published by the Free Software Foundation; either version 2 of the
   8 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 Library General Public License for more details.
  14
  15 You should have received a copy of the GNU Library General Public
  16 License along with the GNU C Library; see the file COPYING.LIB.  If
  17 not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18 Boston, MA 02111-1307, USA.  */
  19
  20 #include <errno.h>
  21 #include <string.h>
  22 #include <unistd.h>
  23 #include <utmp.h>
  24
  25
  26 /* For implementing this function we don't use the getutent_r function
  27    because we can avoid the reposition on every new entry this way.  */
  28 int
  29 __getutid_r (const struct utmp *id, struct utmp **utmp,
  30              struct utmp_data *utmp_data)
  31 {
  32 #if (_HAVE_UT_ID - 0) && (_HAVE_UT_TYPE - 0)
  33   /* Test whether ID has any of the legal types.  */
  34   if (id->ut_type != RUN_LVL && id->ut_type != BOOT_TIME
  35       && id->ut_type != OLD_TIME && id->ut_type != NEW_TIME
  36       && id->ut_type != INIT_PROCESS && id->ut_type != LOGIN_PROCESS
  37       && id->ut_type != USER_PROCESS && id->ut_type != DEAD_PROCESS)
  38     /* No, using '<' and '>' for the test is not possible.  */
  39     {
  40       __set_errno (EINVAL);
  41       return -1;
  42     }
  43
  44   /* Open utmp file if not already done.  */
  45   if (utmp_data->ut_fd == -1)
  46     {
  47       setutent_r (utmp_data);
  48       if (utmp_data->ut_fd == -1)
  49         return -1;
  50     }
  51
  52   /* Position file correctly.  */
  53   if (lseek (utmp_data->ut_fd, utmp_data->loc_utmp, SEEK_SET) == -1)
  54     return -1;
  55
  56   if (id->ut_type == RUN_LVL || id->ut_type == BOOT_TIME
  57       || id->ut_type == OLD_TIME || id->ut_type == NEW_TIME)
  58     {
  59       /* Search for next entry with type RUN_LVL, BOOT_TIME,
  60          OLD_TIME, or NEW_TIME.  */
  61
  62       while (1)
  63         {
  64           /* Read the next entry.  */
  65           if (read (utmp_data->ut_fd, &utmp_data->ubuf, sizeof (struct utmp))
  66               != sizeof (struct utmp))
  67             {
  68               utmp_data->loc_utmp = 0; /* Mark loc_utmp invalid. */
  69               __set_errno (ESRCH);
  70               return -1;
  71             }
  72
  73           /* Update position pointer.  */
  74           utmp_data->loc_utmp += sizeof (struct utmp);
  75
  76           if (id->ut_type == utmp_data->ubuf.ut_type)
  77             break;
  78         }
  79     }
  80   else
  81     {
  82       /* Search for the next entry with the specified ID and with type
  83          INIT_PROCESS, LOGIN_PROCESS, USER_PROCESS, or DEAD_PROCESS.  */
  84
  85       while (1)
  86         {
  87           /* Read the next entry.  */
  88           if (read (utmp_data->ut_fd, &utmp_data->ubuf, sizeof (struct utmp))
  89               != sizeof (struct utmp))
  90             {
  91               utmp_data->loc_utmp = 0; /* Mark loc_utmp invalid. */
  92               __set_errno (ESRCH);
  93               return -1;
  94             }
  95
  96           /* Update position pointer.  */
  97           utmp_data->loc_utmp += sizeof (struct utmp);
  98
  99           if ((   utmp_data->ubuf.ut_type == INIT_PROCESS
 100                || utmp_data->ubuf.ut_type == LOGIN_PROCESS
 101                || utmp_data->ubuf.ut_type == USER_PROCESS
 102                || utmp_data->ubuf.ut_type == DEAD_PROCESS)
 103               && (strncmp (utmp_data->ubuf.ut_id, id->ut_id, sizeof id->ut_id)
 104                   == 0))
 105             break;
 106         }
 107     }
 108
 109   *utmp = &utmp_data->ubuf;
 110
 111   return 0;
 112 #else   /* !_HAVE_UT_ID && !_HAVE_UT_TYPE */
 113   __set_errno (ENOSYS);
 114   return -1;
 115 #endif
 116 }
 117 weak_alias (__getutid_r, getutid_r)