krb5_initlog man page
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
Kerberos 5 Library (libkrb5, -lkrb5)
(*krb5_log_log_func_t)(const char *time, const char *message, void *data);
krb5_addlog_dest(krb5_context context, krb5_log_facility *facility, const char *destination);
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_closelog(krb5_context context, krb5_log_facility *facility);
krb5_initlog(krb5_context context, const char *program, krb5_log_facility **facility);
krb5_log(krb5_context context, krb5_log_facility *facility, int level, const char *format, ...);
krb5_log_msg(krb5_context context, krb5_log_facility *facility, char **reply, int level, const char *format, ...);
krb5_openlog(krb5_context context, const char *program, krb5_log_facility **facility);
krb5_vlog(krb5_context context, krb5_log_facility *facility, int level, const char *format, va_list arglist);
krb5_vlog_msg(krb5_context context, krb5_log_facility *facility, char **reply, int level, const char *format, va_list arglist);
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. The defined destinations (as specified in Each destination may optionally be prepended with a range of logging levels, specified as
NOTICE). The default values (as well as the values used for unrecognised values), are
AUTH, respectively. See syslog(3) for a list of priorities and facilities.
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.
The defined destinations (as specified in
Each destination may optionally be prepended with a range of logging levels, specified as
[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.
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().
Explore man page connections for krb5_initlog(3).
krb5_addlog_dest(3), krb5_addlog_func(3), krb5_closelog(3), krb5_log(3), krb5_log_msg(3), krb5_openlog(3), krb5_vlog(3) and krb5_vlog_msg(3) are aliases of krb5_initlog(3).