login_times(3)

NAME

parse_lt, in_ltm, in_ltms - functions for parsing and check

ing login time
periods

LIBRARY

System Utilities Library (libutil, -lutil)

SYNOPSIS

#include <sys/types.h>
#include <time.h>
#include <login_cap.h>
login_time_t
parse_lt(const char *str);
int
in_ltm(const login_time_t *lt, struct tm *t, time_t *ends);
int
in_ltms(const login_time_t *lt, struct tm *t, time_t *ends);

DESCRIPTION

This set of functions may be used for parsing and checking

login and session times against a predefined list of allowed login times

as used in
login.conf(5).

The format of allowed and disallowed session times specified

in the
times.allow and times.deny capability fields in a login

class are comprised of a prefix which specifies one or more 2- or 3-char

acter day
codes, followed by a start and end time in 24 hour format

separated by a
hyphen. Day codes may be concatenated together to select

specific days,
or the special mnemonics "Any" and "All" (for any/all days

of the week),
"Wk" for any day of the week (excluding Saturdays and Sun

days) and "Wd"
for any weekend day may be used.

For example, the following time period:

MoThFrSa1400-2200

is interpreted as Monday, Thursday through Saturday between

the hours of
2pm and 10pm.

Wd0600-1800

means Saturday and Sunday, between the hours of 6am through

6pm, and

Any0400-1600

means any day of the week, between 4am and 4pm.

Note that all time periods reference system local time.

The parse_lt() function converts the ASCII representation of

a time
period into a structure of type login_time_t. This is de

fined as:

typedef struct login_time
{

u_short lt_start; /* Start time */
u_short lt_end; /* End time */
u_char lt_dow; /* Days of week */

} login_time_t;

The lt_start and lt_end fields contain the number of minutes

past midnight at which the described period begins and ends. The

lt_dow field is
a bit field, containing one bit for each day of the week and

one bit
unused. A series LTM_* macros may be used for testing bits

individually
and in combination. If no bits are set in this field

i.e., it contains
the value LTM_NONE - then the entire period is assumed in

valid. This is
used as a convention to mark the termination of an array of

login_time_t
values. If parse_lt() returns a login_time_t with lt_dow

equal to
LTM_NONE then a parsing error was encountered.

The remaining functions provide the ability to test a given

time_t or
struct tm value against a specific time period or array of

time periods.
The in_ltm() function determines whether the given time de

scribed by the
struct tm passed as the second parameter falls within the

period
described by the first parameter. A boolean value is re

turned, indicating whether or not the time specified falls within the peri

od. If the
time does fall within the time period, and the third parame

ter to the
function is not NULL, the time at which the period ends rel

ative to the
time passed is returned.

The in_ltms() function is similar to in_ltm() except that

the first
parameter must be a pointer to an array of login_time_t ob

jects, which is
up to LC_MAXTIMES (64) elements in length, and terminated by

an element
with its lt_dow field set to LTM_NONE.

RETURN VALUES

The parse_lt() function returns a filled in structure of

type
login_time_t containing the parsed time period. If a pars

ing error
occurs, the lt_dow field is set to LTM_NONE (i.e., 0).

The in_ltm() function returns non-zero if the given time

falls within the
period described by the login_time_t passed as the first pa

rameter.

The in_ltms() function returns the index of the first time

period found
in which the given time falls, or -1 if none of them apply.

SEE ALSO

getcap(3), login_cap(3), login_class(3), login.conf(5),

termcap(5)

BSD January 2, 1997

BSD