GETUTX(3C-SVR4) RISC/os Reference Manual GETUTX(3C-SVR4)
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 ut_user[32]; /* user login name */
char ut_id[4]; /* /sbin/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 {
short e_termination; /* termination status */
short e_exit; /* exit status */
} ut_exit; /* exit status of a process
/* marked as DEAD_PROCESS */
struct timeval ut_tv; /* time entry was made */
short ut_syslen; /* significant length of ut_host */
/* including terminating null */
char ut_host[257]; /* host name, if remote */
};
Printed 11/19/92 Page 1
GETUTX(3C-SVR4) RISC/os Reference Manual GETUTX(3C-SVR4)
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 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.
getutxline 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.
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 (otherwise
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.
Page 2 Printed 11/19/92
GETUTX(3C-SVR4) RISC/os Reference Manual GETUTX(3C-SVR4)
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 initial-
ized 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
Printed 11/19/92 Page 3
GETUTX(3C-SVR4) RISC/os Reference Manual GETUTX(3C-SVR4)
files.
Page 4 Printed 11/19/92