LOGIN_TIMES(3) BSD Library Functions Manual LOGIN_TIMES(3)NAME
parse_lt, in_lt, in_ltm, in_ltms, in_lts — functions for parsing and
checking login time periods
System Utilities Library (libutil, -lutil)
parse_lt(const char *str);
in_lt(const login_time_t *lt, time_t *ends);
in_ltm(const login_time_t *lt, struct tm *t, time_t *ends);
in_ltms(const login_time_t *lt, struct tm *t, time_t *ends);
in_lts(const login_time_t *lt, time_t *ends);
This set of functions may be used for parsing and checking login and ses‐
sion times against a predefined list of allowed login times as used in
The format of allowed and disallowed session times specified in the
times.allow and times.deny capability fields in a login class are com‐
prised of a prefix which specifies one or more 2- or 3-character 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 Sundays) and "Wd"
for any weekend day may be used.
For example, the following time period:
is interpreted as Monday, Thursday through Saturday between the hours of
2pm and 10pm.
means Saturday and Sunday, between the hours of 6am through 6pm, and
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 defined as:
typedef struct login_time
u_short lt_start; /* Start time */
u_short lt_end; /* End time */
u_char lt_dow; /* Days of week */
The lt_start and lt_end fields contain the number of minutes past mid‐
night 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 invalid. 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 described by the
struct tm passed as the second parameter falls within the period
described by the first parameter. A boolean value is returned, indicat‐
ing whether or not the time specified falls within the period. If the
time does fall within the time period, and the third parameter to the
function is not NULL, the time at which the period ends relative 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 objects, which is
up to LC_MAXTIMES (64) elements in length, and terminated by an element
with its lt_dow field set to LTM_NONE.
The in_lt() and in_lts() functions are equivalent to in_ltm() and
in_ltms(), respectively, with the second argument set to the current time
as returned by localtime(3).
The parse_lt() function returns a filled in structure of type
login_time_t containing the parsed time period. If a parsing 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 parameter.
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 ALSOgetcap(3), login_cap(3), login_class(3), login.conf(5), termcap(5)BSD October 20, 2008 BSD