getutxent(3C) manual page
Table of Contents
getutxent, getutxid, getutxline, pututxline, setutxent, endutxent,
utmpxname, getutmp, getutmpx, updwtmp, updwtmpx - access utmpx file entry
#include <utmpx.h>
struct utmpx *getutxent(void);
struct utmpx *getutxid(const struct utmpx *id);
struct utmpx *getutxline(const struct utmpx *line);
struct utmpx *pututxline(const struct utmpx *utmpx);
void setutxent(void);
void endutxent(void);
int utmpxname(const char *file);
void getutmp(struct utmpx *utmpx, struct utmp *utmp);
void getutmpx(struct utmp *utmp, struct utmpx *utmpx);
void updwtmp(char *wfile, struct utmp *utmp);
void updwtmpx(char *wfilex, struct utmpx *utmpx);
Unsafe
getutxent(), getutxid(), and getutxline()
each return a pointer to a utmpx structure with the following members:
| char | ut_user[32]; | /* user login name */ |
| char | ut_id[4]; | /* /etc/inittab id */ |
| | /*
(usually line #) */ |
| char | ut_line[32]; | /* device name (console, lnxx) */ |
| pid_t | ut_pid; | /*
process id */ |
| short | ut_type; | /* type of entry */ |
| struct | exit_status ut_exit; | /*
exit status of a process */ |
| | /* marked as DEAD_PROCESS
*/ |
| struct | timeval ut_tv; | /*
time entry was made */ |
| long | ut_session; | /* session ID, used for windowing
*/ |
| long | pad[5]; | /* reserved for future use */ |
| short | ut_syslen; | /* significant
length of ut_host */ |
| | /* including terminating null */ |
| char | ut_host[257]; | /*
host name, if remote */ |
The structure exit status includes the following
members:
| short | e_termination; | /* termination status */ |
| short | e_exit; | /* exit
status */ |
Reads in the next entry from a utmpx-like file. If the
file is not already open, it opens it. If it reaches the end of the file,
it fails.
Searches forward from the current point in the utmpx
file until it finds an entry with a ut_type matching id->ut_type if the type
specified is RUN_LVL
, BOOT_TIME
, OLD_TIME
, or NEW_TIME
. If the type specified
in id is INIT_PROCESS
, LOGIN_PROCESS
, USER_PROCESS
, or DEAD_PROCESS
, then
getutxid() 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.
Searches forward from the current point in the utmpx file
until it finds an entry of the type LOGIN_PROCESS
or USER_PROCESS
which
also has a ut_line string matching the line->ut_line string. If the end of
file is reached without a match, it fails.
Writes out the supplied
utmpx structure into the utmpx file. It uses getutxid() 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 pututxline() will have searched
for the proper entry using one of the getutx() routines. If so, pututxline()
will not search. If pututxline() does not find a matching slot for the
new entry, it will add a new entry to the end of the file. It returns a
pointer to the utmpx structure. When called by a non-root user, pututxline()
invokes a setuid() root program to verify and write the entry, since /etc/utmpx
is normally writable only by root. In this event, the ut_name field must
correspond to the actual user name associated with the process; the ut_type
field must be either USER_PROCESS
or DEAD_PROCESS
; and the ut_line field
must be a device special file and be writable by the user.
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.
Closes the currently open file.
Allows the user to
change the name of the file examined, from /var/adm/utmpx to any other
file. It is most often expected that this other file will be /var/adm/wtmpx.
If the file does not exist, this will not be apparent until the first attempt
to reference the file is made. utmpxname() does not open the file. It just
closes the old file if it is currently open and saves the new file name.
The new file name must end with the ‘‘x’’ character to allow the name of the
corresponding utmp file to be easily obtainable; otherwise, an error code
of 1 is returned.
Copies the information stored in the fields of
the utmpx structure to the corresponding fields of the utmp structure. If
the information in any field of utmpx does not fit in the corresponding
utmp field, the data is truncated. (See getutent(3C)
for utmp structure)
Copies the information stored in the fields of the utmp structure
to the corresponding fields of the utmpx structure. (See getutent(3C)
for
utmp structure)
Checks the existence of wfile and its parallel
file, whose name is obtained by appending an ‘‘x’’ to wfile. If only one of
them exists, the second one is created and initialized to reflect the state
of the existing file. utmp is written to wfile and the corresponding
utmpx structure is written to the parallel file.
Checks the existence
of wfilex and its parallel file, whose name is obtained by truncating the
final ‘‘x’’ from wfilex. If only one of them exists, the second one is created
and initialized to reflect the state of the existing file. utmpx is written
to wfilex, and the corresponding utmp structure is written to the parallel
file.
A null pointer is returned upon failure to read, whether
for permissions or having reached the end of file, or upon failure to write.
- /var/adm/utmp
- contains current user access and adminstrative information
(old format)
- /var/adm/utmpx
- contains current user access and adminstration
information (new format)
- /var/adm/wtmp
- contains a history of user access
and adminstrative information.
- /var/adm/wtmpx
- contains a history of user
access and adminstrative information.
getutent(3C)
, ttyslot(3C)
,
utmp(4)
, utmpx(4)
The most current entry is saved in a static structure.
Multiple accesses require that it be copied before further accesses are
made. On each call to either getutxid() or getutxline(), the routine examines
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 getutxline() to search for multiple occurrences it
would be necessary to zero out the static after each success, or getutxline()
would just return the same structure over and over again. There is one exception
to the rule about emptying the structure before further reads are done.
The implicit read done by pututxline() (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 getutxent(), getutxid(), or getutxline() routines,
if the user has just modified those contents and passed the pointer back
to pututxline().
These routines use buffered standard I/O
for input, but
pututxline() uses an unbuffered write to avoid race conditions between
processes trying to modify the utmpx and wtmpx files.
Table of Contents
![[Go to CFHT Home Page]](/images/cfht-icon.gif){kind=icon}
Man Pages 
Back to Software Index 
Manpage Top Level