NAME

     krb5_initlog, krb5_openlog, krb5_closelog, krb5_addlog_dest, krb5_addlog_func, krb5_log,
     krb5_vlog, krb5_log_msg, krb5_vlog_msg — Heimdal logging functions

LIBRARY

     Kerberos 5 Library (libkrb5, -lkrb5)

SYNOPSIS

     #include <krb5.h>

     typedef void
     (*krb5_log_log_func_t)(const char *time, const char *message, void *data);

     typedef void
     (*krb5_log_close_func_t)(void *data);

     krb5_error_code
     krb5_addlog_dest(krb5_context context, krb5_log_facility *facility,
         const char *destination);

     krb5_error_code
     krb5_addlog_func(krb5_context context, krb5_log_facility *facility, int min, int max,
         krb5_log_log_func_t log, krb5_log_close_func_t close, void *data);

     krb5_error_code
     krb5_closelog(krb5_context context, krb5_log_facility *facility);

     krb5_error_code
     krb5_initlog(krb5_context context, const char *program, krb5_log_facility **facility);

     krb5_error_code
     krb5_log(krb5_context context, krb5_log_facility *facility, int level, const char *format,
         ...);

     krb5_error_code
     krb5_log_msg(krb5_context context, krb5_log_facility *facility, char **reply, int level,
         const char *format, ...);

     krb5_error_code
     krb5_openlog(krb5_context context, const char *program, krb5_log_facility **facility);

     krb5_error_code
     krb5_vlog(krb5_context context, krb5_log_facility *facility, int level, const char *format,
         va_list arglist);

     krb5_error_code
     krb5_vlog_msg(krb5_context context, krb5_log_facility *facility, char **reply, int level,
         const char *format, va_list arglist);

DESCRIPTION

     These functions logs messages to one or more destinations.

     The krb5_openlog() function creates a logging facility, that is used to log messages. A
     facility consists of one or more destinations (which can be files or syslog or some other
     device). The program parameter should be the generic name of the program that is doing the
     logging. This name is used to lookup which destinations to use. This information is
     contained in the logging section of the krb5.conf configuration file.  If no entry is found
     for program, the entry for default is used, or if that is missing too, SYSLOG will be used
     as destination.

     To close a logging facility, use the krb5_closelog() function.

     To log a message to a facility use one of the functions krb5_log(), krb5_log_msg(),
     krb5_vlog(), or krb5_vlog_msg().  The functions ending in _msg return in reply a pointer to
     the message that just got logged. This string is allocated, and should be freed with free().
     The format is a standard printf() style format string (but see the BUGS section).

     If you want better control of where things gets logged, you can instead of using
     krb5_openlog() call krb5_initlog(), which just initializes a facility, but doesn't define
     any actual logging destinations. You can then add destinations with the krb5_addlog_dest()
     and krb5_addlog_func() functions.  The first of these takes a string specifying a logging
     destination, and adds this to the facility. If you want to do some non-standard logging you
     can use the krb5_addlog_func() function, which takes a function to use when logging.  The
     log function is called for each message with time being a string specifying the current
     time, and message the message to log.  close is called when the facility is closed. You can
     pass application specific data in the data parameter. The min and max parameter are the same
     as in a destination (defined below). To specify a max of infinity, pass -1.

     krb5_openlog() calls krb5_initlog() and then calls krb5_addlog_dest() for each destination
     found.

   Destinations
     The defined destinations (as specified in krb5.conf) follows:

           STDERR
                This logs to the program's stderr.

           FILE:/file

           FILE=/file
                Log to the specified file. The form using a colon appends to the file, the form
                with an equal truncates the file. The truncating form keeps the file open, while
                the appending form closes it after each log message (which makes it possible to
                rotate logs). The truncating form is mainly for compatibility with the MIT
                libkrb5.

           DEVICE=/device
                This logs to the specified device, at present this is the same as FILE:/device.

           CONSOLE
                Log to the console, this is the same as DEVICE=/dev/console.

           SYSLOG[:priority[:facility]]
                Send messages to the syslog system, using priority, and facility. To get the name
                for one of these, you take the name of the macro passed to syslog(3), and remove
                the leading LOG_ (LOG_NOTICE becomes NOTICE).  The default values (as well as the
                values used for unrecognised values), are ERR, and AUTH, respectively.  See
                syslog(3) for a list of priorities and facilities.

     Each destination may optionally be prepended with a range of logging levels, specified as
     min-max/.  If the level parameter to krb5_log() is within this range (inclusive) the message
     gets logged to this destination, otherwise not. Either of the min and max valued may be
     omitted, in this case min is assumed to be zero, and max is assumed to be infinity.  If you
     don't include a dash, both min and max gets set to the specified value. If no range is
     specified, all messages gets logged.

EXAMPLES

           [logging]
                   kdc = 0/FILE:/var/log/kdc.log
                   kdc = 1-/SYSLOG:INFO:USER
                   default = STDERR

     This will log all messages from the kdc program with level 0 to /var/log/kdc.log, other
     messages will be logged to syslog with priority LOG_INFO, and facility LOG_USER.  All other
     programs will log all messages to their stderr.

SEE ALSO

     syslog(3), krb5.conf(5)

BUGS

     These functions use asprintf() to format the message. If your operating system does not have
     a working asprintf(), a replacement will be used. At present this replacement does not
     handle some correct conversion specifications (like floating point numbers). Until this is
     fixed, the use of these conversions should be avoided.

     If logging is done to the syslog facility, these functions might not be thread-safe,
     depending on the implementation of openlog(), and syslog().