getut(3)                            CLIX                            getut(3)



  NAME

    getut: getutent, getutid, getutline, pututline, setutent, endutent,
    utmpname - Accesses utmp file entry

  LIBRARY

    Standard C Library (libc.a)

  SYNOPSIS

    #include <utmp.h>

    struct utmp *getutent(
      void );

    struct utmp *getutid(
      struct utmp *id );

    struct utmp *getutline(
      struct utmp *line );

    void pututline(
      struct utmp *utmp );

    void setutent(
      void );

    void endutent(
      void );

    void utmpname(
      char file );

  PARAMETERS

    id
    line
    utmp   Specifies an entry in the utmp file.

    file   Specifies the name of a file other than the normal ``utmp'' file.

  DESCRIPTION

    The getutent(), getutid(), and getutline() functions each return a pointer
    to a structure of the following type:

    struct utmp {
         char   ut_user[8];  /* User login name */
         char   ut_id[4];    /* /etc/inittab id (usually line #) */
         char   ut_line[12]; /* device name (console, lnxx) */



  2/94 - Intergraph Corporation                                              1

  getut(3)                            CLIX                            getut(3)



         short  ut_pid;      /* process id */
         short  ut_type;     /* type of entry */
         struct exit_status {
              short e_termination; /* Process termination status */
              short e_exit;        /* Process exit status */
         } ut_exit;          /* The exit status of a process */
                             /* marked as DEAD_PROCESS. */
         time_t ut_time;     /* time entry was made */
    }

    The getutent() function reads in the next entry from a utmp-like file.  If
    the file is not already open, it opens it.  If it reaches the end of the
    file, it fails.

    The getutid() function searches forward from the current point in the utmp
    file until it finds an entry with a ut_type matching id->ut_type if the
    type specified is or if the type specified in id is or then getutid() will
    return a pointer to the first entry whose type is one of these four and
    whose ut_id field matches id->ut_id.  If the end-of-file is reached
    without a match, it fails.

    The getutline() function searches forward from the current point in the
    utmp file until it finds an entry of the type LOGIN_PROCESS or
    USER_PROCESS which also has a ut_line line->ut_line.

    The pututline() function writes out the supplied utmp utmp file.  It uses
    getutid() to search forward for the proper place if it finds that it is
    not already at the proper place.  It is expected that normally the user of
    pututline() will have searched for the proper entry using one of the getut
    functions.  If so, pututline() will not search.  If pututline() does not
    find a matching slot for the new entry, it will add a new entry to the end
    of the file.

    The setutent() function resets the input stream to the beginning of the
    file.  This should be done before each search for a new entry if it is
    desired that the entire file be examined.

    The endutent() function closes the currently open file.

    The utmpname() function allows the user to change the name of the file
    examined, from /etc/utmp to any other file.  It is most often expected
    that this other file will be /etc/wtmp.  If the file does not exist, this
    will not be apparent until the first attempt to reference the file is
    made.  The utmpname() function does not open the file.  It just closes the
    old file if it is currently open and saves the new filename.

  FILES

    /etc/utmp

    /etc/wtmp



  2                                              Intergraph Corporation - 2/94

  getut(3)                            CLIX                            getut(3)



  NOTES

    The most current entry is saved in a static structure.  Multiple accesses
    require that it be copied before further accesses are made.  Each call to
    either getutid() or getutline() sees the function examine the static
    structure before performing more I/O.  If the contents of the static
    structure match what it is searching for, it looks no further.  For this
    reason to use getutline() to search for multiple occurrences, it would be
    necessary to zero out the static after each success, or getutline() would
    just return the same pointer over and over again.  There is one exception
    to the rule about removing the structure before further reads are done.
    The implicit read done by pututline() (if it finds that it is not already
    at the correct place in the file) will not hurt the contents of the static
    structure returned by the getutent(), getutid() or getutline() functions,
    if the user has just modified those contents and passed the pointer back
    to pututline().

    These functions use buffered standard I/O for input, but pututline() uses
    an unbuffered nonstandard write to avoid race conditions between processes
    trying to modify the utmp and wtmp files.

  RETURN VALUES

    A NULL pointer is returned upon failure to read, whether for permissions
    or having reached the end-of-file, or upon failure to write.

  RELATED INFORMATION

    Functions:  ttyslot(3)

    Files:  utmp(4)























  2/94 - Intergraph Corporation                                              3