[Bug 183729] Re: compat: utmp not cleared on tty logout

[Steve Langasek]

** Changed in: upstart (Ubuntu)
       Status: Confirmed => Fix Released

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Title:
  compat: utmp not cleared on tty logout

Status in Upstart:
  Fix Released
Status in “kdebase-workspace” package in Ubuntu:
  Invalid
Status in “upstart” package in Ubuntu:
  Fix Released
Status in “upstart” package in Fedora:
  In Progress

Bug description:
  Log into tty1, then tty2 and then log out of both.  Now run a w
  command and you should see something similar to the following;

  mac at tootoo:~/source/procps-3.2.7/proc$ w
   10:39:09 up 33 days, 23:11,  4 users,  load average: 1.31, 0.62, 0.39
  USER     TTY      FROM              LOGIN@   IDLE   JCPU   PCPU WHAT
  mac     tty7     :0               11Jan08  4:34m  7:24m 36.02s x-session-manager
  mac     pts/1    :0.0             08:54    0.00s  0.19s  0.00s w

  It shows that 4 users are logged in.  Obviously this is wrong.  I
  wrote a small C utility to hack out what w and uptime get as
  information from utmp.

  
  #include <string.h>
  #include <stdlib.h>
  #include <pwd.h>
  #include <unistd.h>
  #include <utmp.h>
  #include <stdio.h>

  int main(int argc, char *argv[])
  {
    struct utmp *utmpstruct;
    struct utmp entry;

    //system("echo before adding entry:;who");

    setutent();
    //pututline(&entry);
    while ((utmpstruct = getutent())){
          if ((utmpstruct->ut_type == USER_PROCESS) && (utmpstruct->ut_name[0] != '\0'))
          printf(utmpstruct->ut_line);
          printf("\t");
          printf("%d",utmpstruct->ut_pid);
          printf("\n");
    }
    endutent();
    return 0;
  }

  You'll get an output like this

  mac at tootoo:~$ ./a.out 
          0
          50
          4305
          4306
  tty2    14989
          4312
  tty1    4313
          4314
  tty7    30255
          0
  pts/1   9712
          0
          0
          0
          0
          0
          20929
          14914
          15034

  However, running the following , to try to find the pid for the tty1
  process, gives;

  mac at tootoo:~/source/procps-3.2.7/proc$ ps aux | grep 4313
  mac     15524  0.0  0.0   2988   768 pts/1    R+   10:42   0:00 grep 4313
  mac at tootoo:~/source/procps-3.2.7/proc$ 

  This is obviously wrong, utmp still has the old process id's
  associated as being logged in.

  Running the following gives the new tty pid

  mac at tootoo:~/source/procps-3.2.7/proc$ ps aux | grep tty1
  root     14914  0.0  0.0   1692   516 tty1     Ss+  10:33   0:00 /sbin/getty 38400 tty1
  mac     15605  0.0  0.0   2988   764 pts/1    R+   10:44   0:00 grep tty1
  mac at tootoo:~/source/procps-3.2.7/proc$ 

  There is now a new pid for tty1

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