getutx(3C) getutx(3C)
NAME
getutx: getutxent, getutxid, getutxline, pututxline, setutxent,
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 */
};
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getutx(3C) 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 utid field matches id-
>utid. If the end of file is reached without a match, it fails.
uttype member Other members with meaningful data
___________________________________________________________________
EMPTY No others
BOOTTIME uttv
OLDTIME uttv
NEWTIME uttv
USERPROCESS utid, utuser (login name of the user), utline,
utpid, uttv
INITPROCESS utid, utpid, uttv
LOGINPROCESS utid, utuser (implementation-specific name of
the login process), utpid, uttv
DEADPROCESS utid, utpid, uttv
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 utline 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 searching the entire file for a new entry.
endutxent() closes the open file.
utmpxname() allows the user to change the name of the file examined,
from /var/adm/utmpx to any other filename. In most cases, 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 filename. The new filename 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.
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getutx(3C) getutx(3C)
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.
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 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.
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 corre-
sponding utmp structure is written to the parallel file.
RESULT
A null pointer is returned upon failure to read, whether for permis-
sions or having reached the end of file, or upon failure to write.
ERRORS
The following error code description is function-specific. You will
find a general description in introprm2(2) or in errno(5).
No errors are defined for the endutxent(), getutxent(), getutxid(),
getutxline() and setutxent() functions.
The pututxline() function may fail if:
EPERM The process does not have appropriate privileges.
NOTES
The most current entry is saved in a static structure. Before reac-
cessing the file, this entry must be copied. 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 identical entries, it would be
necessary to zero out the static area after each success, or
getutxline() would just return the same structure over and over again.
There is one exception to this rule: the implicit read done by
pututxline() (if the correct place in the file has not yet been
reached) 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().
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getutx(3C) getutx(3C)
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.
FILES
/var/adm/utmp
/var/adm/utmpx
/var/adm/wtmp
/var/adm/wtmpx
SEE ALSO
ttyslot(3C), utmp(4), utmpx(4).
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