getutx(3C) COMPATIBILITY FUNCTIONS getutx(3C)
NAME
getutx: getutxent, getutxid, getutxline, pututxline, setutx-
ent, endutxent, utmpxname, getutmp, getutmpx, updwtmp,
updwtmpx - access utmpx file entry
SYNOPSIS
#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);
DESCRIPTION
getutxent, getutxid, and getutxline each return a pointer to
a structure of the following type:
struct utmpx {
char utuser[32]; /* user login name */
char utid[4]; /* /sbin/inittab id (usually */
/* line #) */
char utline[32]; /* device name (console, lnxx) */
pidt utpid; /* process id */
short uttype; /* type of entry */
struct exitstatus {
short etermination; /* termination status */
short eexit; /* exit status */
} utexit; /* exit status of a process
/* marked as DEADPROCESS */
struct timeval uttv; /* time entry was made */
short utsyslen; /* significant length of uthost */
/* including terminating null */
char uthost[257]; /* host name, if remote */
};
Last change: C Programming Language Utilities 1
getutx(3C) COMPATIBILITY FUNCTIONS getutx(3C)
getutxent 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.
getutxid searches forward from the current point in the
utmpx file until it finds an entry with a uttype matching
id->uttype if the type specified is RUNLVL, BOOTTIME,
OLDTIME, or NEWTIME. If the type specified in id is
INITPROCESS, LOGINPROCESS, USERPROCESS, or DEADPROCESS,
then getutxid will return a pointer to the first entry whose
type is one of these four and whose ut_id field matches
id->utid. If the end of file is reached without a match,
it fails.
getutxline searches forward from the current point in the
utmpx file until it finds an entry of the type LOGINPROCESS
or USERPROCESS which also has a ut_line string matching the
line->utline string. If the end of file is reached without
a match, it fails.
pututxline 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.
setutxent 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.
endutxent closes the currently open file.
utmpxname 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 (other-
wise an error code of 1 is returned).
getutmp 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.
Last change: C Programming Language Utilities 2
getutx(3C) COMPATIBILITY FUNCTIONS getutx(3C)
getutmpx copies the information stored in the fields of the
utmp structure to the corresponding fields of the utmpx
structure.
updwtmp 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 ini-
tialized to reflect the state of the existing file. utmp is
written to wfile and the corresponding utmpx structure is
written to the parallel file.
updwtmpx 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.
FILES
/var/adm/utmp, /var/adm/utmpx
/var/adm/wtmp, /var/adm/wtmpx
SEE ALSO
ttyslot(3C), utmp(4), utmpx(4).
DIAGNOSTICS
A null pointer is returned upon failure to read, whether for
permissions or having reached the end of file, or upon
failure to write.
NOTES
The most current entry is saved in a static structure. Mul-
tiple 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 struc-
ture 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
Last change: C Programming Language Utilities 3
getutx(3C) COMPATIBILITY FUNCTIONS getutx(3C)
files.
Last change: C Programming Language Utilities 4