logger.c

// Abstract logging system used to facilitate multiple modes
// of logging

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifndef WIN32
#include <syslog.h>
#endif
#include <errno.h>
#include <stdarg.h>
#include <ctype.h>

#include "logger.h"

#ifndef WIN32
static int _LOGGER_mode = _LOGGER_SYSLOG;
static int _LOGGER_syslog_mode = LOG_MAIL|LOG_INFO;
#else
static int _LOGGER_mode = _LOGGER_STDERR;
static int _LOGGER_syslog_mode = 0;
#endif
static FILE *_LOGGER_outf;

struct LOGGER_globals {
	int wrap;
	int wraplength;
};

	// Create and Initialise the global structure for LOGGER,
	//		we init it to have NO wrapping.

static struct LOGGER_globals LOGGER_glb={ 0, 0 };


/*------------------------------------------------------------------------
Procedure:     LOGGER_get_file ID:1
Purpose:       Returns the pointer to the file being used to output logs to
Input:
Output:
Errors:
------------------------------------------------------------------------*/
FILE *LOGGER_get_file( void )
{
	return _LOGGER_outf;
}


/*------------------------------------------------------------------------
Procedure:     LOGGER_set_output_mode ID:1
Purpose:       Sets the message/log output method, ie, stderr, stdout
or syslog
Input:
Output:
Errors:
------------------------------------------------------------------------*/
int LOGGER_set_output_mode( int modechoice )
{
	_LOGGER_mode = modechoice;
	return 0;
}

/*------------------------------------------------------------------------
Procedure:     LOGGER_set_output_file ID:1
Purpose:       Sets the output file for when _LOGGER_mode is set to
_LOGGER_file
Input:
Output:
Errors:
------------------------------------------------------------------------*/
int LOGGER_set_output_file( FILE *f )
{
	_LOGGER_outf = f;
	return 0;
}

/*------------------------------------------------------------------------
Procedure:     LOGGER_set_syslog_mode ID:1
Purpose:       Sets the mode that messaging to the syslog daemon will
be sent as (ie, LOG_MAIL|LOG_INFO)
Input:
Output:
Errors:
------------------------------------------------------------------------*/
int LOGGER_set_syslog_mode( int syslogmode )
{
	_LOGGER_syslog_mode = syslogmode;
	return 0;
}




/*------------------------------------------------------------------------
Procedure:     LOGGER_set_logfile ID:1
Purpose:       Opens and setups the internal Log file file pointer with the
log file as given by lfname
Input:
Output:
Errors:
------------------------------------------------------------------------*/
int LOGGER_set_logfile( char *lfname )
{
	int result = 0;

	_LOGGER_outf = fopen(lfname,"a");
	if (!_LOGGER_outf)
	{
#ifndef WIN32
		syslog(1,"LOGGER_set_logfile: ERROR - Cannot open logfile '%s' (%s)",lfname,strerror(errno));
#else
		fprintf(stderr, "LOGGER_set_logfile: ERROR - Cannot open logfile '%s' (%s)\n", lfname, strerror(errno));
#endif
		result = -1;
	}

	return result;
}



/*------------------------------------------------------------------------
Procedure:     LOGGER_set_wraplength ID:1
Purpose:       Sets the character count at which LOGGER will break a line
Input:         int length: Positive integer indicating number of chracters at which to wrap at
Output:
Errors:
------------------------------------------------------------------------*/
int LOGGER_set_wraplength( int length )
{
	if ( length >= 0 )
	{
		LOGGER_glb.wraplength = length;
	}

	return LOGGER_glb.wraplength;
}

/*------------------------------------------------------------------------
Procedure:     LOGGER_set_wrap ID:1
Purpose:       Set log output wrapping to on or off
Input:         int level: 0 = no wrap, > 0 = wrap.
Output:
Errors:
------------------------------------------------------------------------*/
int LOGGER_set_wrap( int level )
{
	if ( level >= 0 )
	{
		LOGGER_glb.wrap = level;
	}

	return LOGGER_glb.wrap;
}



/*------------------------------------------------------------------------
Procedure:     LOGGER_close_logfile ID:1
Purpose:       Closes the modules log file pointer.
Input:
Output:
Errors:
------------------------------------------------------------------------*/
int LOGGER_close_logfile( void )
{
	int result = 0;

	if (_LOGGER_outf) fclose(_LOGGER_outf);

	return result;
}



/*------------------------------------------------------------------------
Procedure:     LOGGER_clean_output ID:1
Purpose:       Checks through the output string for any characters which could cause
potential 'isssues' with the data writing calls, items such as stray non-escaped
% characters can cause havoc.
Input:         char *string: Raw string
int maxsize: Maximum available buffer size for this string to expand to
Output:
Errors:
------------------------------------------------------------------------*/
int LOGGER_clean_output( char *string, char **buffer )
{
	char *newstr;
	char *p, *q;
	char *next_space;

	int pc;
	int slen = strlen( string );
	int line_size;
	int maxsize = slen *2;

	// First up, allocate maxsize bytes for a temporary new string.
	newstr = malloc(slen *2 +1); 
	if ( newstr == NULL )
	{
		// FIXME - Report an error here ... to -somewhere-
		return -1;
	}

	p = newstr;
	q = string;
	pc = 0;
	line_size = 0;

	while (slen--)
	{

		// Do we need to apply any wrapping to the output? If so then we
		//		shall embark on a journey of strange space and distance
		//		evaluations to determine if we should wrap now or later

		if ( LOGGER_glb.wrap > 0 )
		{
			if (isspace((int)*q))
			{
				next_space = strpbrk( (q+1), "\t\r\n\v " );
				if (next_space != NULL)
				{
					if ((line_size +(next_space -q)) >= LOGGER_glb.wraplength)
					{
						*p = '\n';
						p++;
						pc++;
						line_size = 0;
					}
				}
			}

			if ( line_size >= LOGGER_glb.wraplength )
			{
				*p = '\n';
				p++;
				pc++;
				line_size = 0;
			}
		}

		// If the string has a % in it, then we need to encode it as
		//	a DOUBLE % symbol.

		if (*q == '%') {
//			if (strchr("fdlsxXn",*(q+1)))
//			{
				*p = '%';
				p++;
				pc++;
//			}
		}

		// Copy the character of the string in
		*p = *q;

		// Move everything along.
		q++;
		p++;
		pc++;
		line_size++;

		if ( pc > (maxsize -1) ) {
			break;
		}
	}

	*p = '\0';

	// This will have to be deallocated later!
	if (newstr) *buffer = newstr;

	return 0;
}

/*------------------------------------------------------------------------
Procedure:     LOGGER_log ID:1
Purpose:       Logs the params as supplied to the required
output as defined by LOGGER_set_output
Input:
Output:
Errors:
------------------------------------------------------------------------*/
int LOGGER_log( char *format, ...)
{
	va_list ptr;
	char tmpoutput[10240];
	char linebreak[]="\n";
	char nolinebreak[]="";
	char *lineend;
	char *output;


	// get our variable arguments
	va_start(ptr,format);

	// produce output, and spit to the log file
#ifdef NO_SNPRINTF
	vsprintf(tmpoutput, format, ptr);
#else
	vsnprintf(tmpoutput,sizeof(tmpoutput),format,ptr);
#endif

	LOGGER_clean_output( tmpoutput, &output );

	if ( output[strlen(output)-1] == '\n' ) {
		lineend = nolinebreak;
	}
	else {
		lineend = linebreak;
	}

	if ( output[strlen(output)-1] == '\n' ) { lineend = nolinebreak; } else { lineend = linebreak; }

	// Send the output to the appropriate output destination
	switch (_LOGGER_mode) {
		case _LOGGER_STDERR:
			fprintf(stderr,"%s%s",output, lineend );
			break;
		case _LOGGER_SYSLOG:
			syslog(_LOGGER_syslog_mode,"%s",output);
			break;
		case _LOGGER_STDOUT:
			fprintf(stdout,"%s%s",output, lineend);
			fflush(stdout);
			break;
		case _LOGGER_FILE:
			fprintf(_LOGGER_outf,"%s%s",output,lineend);
			fflush(_LOGGER_outf);
			break;
		case _LOGGER_NULL: // 20080303-2214:PLD: Added to allow us to direct all logging to NULL.
			break;
		default:
			fprintf(stdout,"LOGGER-Default: %s%s",output,lineend);
	}


	if (output) free(output);

	return 0;
}