Manual Pages  — LOGIN_TIMES

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-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:

    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 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 */
} 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 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, indicating 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).