State of the debugging flags.

[Ian Bruene]

At ESRs request I've trawled through the C sources to see how debug 
logging is handled. First, by way of summary let me present you with a 
couple bits of code:

# define DPRINTF(lvl, arg)                \
     do {                         \
         if (debug >= (lvl))            \
             mprintf arg;            \
     } while (0)

#define TRACE(lvl, arg)                    \
     do {                         \
         if (debug >= (lvl))            \
             mprintf arg;            \
     } while (0)

#define parseprintf(LEVEL, ARGS) if (debug > LEVEL) printf ARGS

Yeah.............

Debug printing is controlled by the debug variable, defined as int debug 
in lib_srbuf.c and extern int debug in declcond.h (both the one in 
include/ and ntpd/) (why isn't this unsigned?). debug==0 is no debug, 
with each level above that including more data as is typical.

The ntpd -d flag increments the debug variable by one for every time it 
appears in the argument list, and also sets nofork.

The ntpd -D n flag sets the debug variable to n, but does not set nofork.

 From there the actual logging is handled through several methods: some 
functions with complicated logging requirements directly use debug to 
setup their own printing, similarly some modules with module-wide 
special requirements define their own debug logging functions.

But in most cases debug logging requires only a simple if (debug>0) 
{printf("blah")}, this is handled through four (4!) different methods 
I've seen so far:

DPRINTF, which is defined in ntpd.h
TRACE, which is defined in ntp_debug.h, and is identical to DPRINTF
parseprintf, which is defined in include/parse.h, and is used 
exclusively in libparse/
adhoc if (debug>n) statements. many of the level one statements also 
merely ask if (debug), rather than a proper if (debug > 0)

Every instance I've seen has the logging code enclosed in an #ifdef 
block for the debug compilation switch, whether directly where it is 
used, of inside of a macro. It would appear that someone began to 
replace the explicit if debugs with macros, but never completed it for 
unknown reasons.

-- 
In the end; what separates a Man, from a Slave? Money? Power?
No. A Man Chooses, a Slave Obeys. -- Andrew Ryan