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loghandler.cc

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/**************************************************************************

    loghandler - generic logfile interface.

    Copyright (C) 2000,2001 Stein Vråle <stein@terminator.net>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

**************************************************************************/
/*
  INTRO

  This is a generic log application providing basic log routines, 
  for use in any application that need a simple way to produce logfiles.

  USAGE

  To use loghandler in a new application, make sure the header file 
  is included in all source files where log messages will be generated.

  Then init the needed loghandles during application startup, by providing 
  the filename to be written into and any additional configuration 
  parameters.

  Finally add one of the message recorders wherever a logmessage is needed,
  and specify the targeted loglevel/class, a printf formatted message 
  template, and any arguments needed for the current logmessage.

  The logf method is meant for permanent logmessages, while the debugf 
  method is meant for development logging - to be easy to turn of  when the 
  applictions runs in production.

  Examples:
  
  loghandler_init(0,"/tmp/app.log");

  logf(MSG_NORMAL,"User %s connected",username);

  debugf(MSG_VERBOSE || LOG_NET,
      "Connection params: ip=%s user=%s pw=%s",hostname,username,password);

  loghandler(MSG_ERROR,LOG_MAIN,"Missing config file %s",filename);


  LOG CLASSIFICATON

  logclass: Used to seperate between different parts of program etc.
  loglevel: Importance of this log message. Higher number is less important.
  logcode: Combined level and class

  RECORDER METHODS

  logf: Record msg by code
  loghandler: Same as logf, but specify by level and class
  debugf: Record msg by code, and add debugflag automatically

  CONTROL METHODS
  
  loghandler_init:

  loghandler_setlevel:
  loghandler_getlevel:

  loghandler_setclass:
  loghandler_getclass:

  INTERNAL FUNCTIONS

  logfilter: Process the logmsg recived from recorder and use filter to 
  find the target loghandle

****************************************************************************/
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <time.h>
#include "loghandler.h"

typedef struct {
    const char *logdevice;
    int logclass;
    int loglevel;
    int logformat;
} loghandle_struct;

loghandle_struct loghandle[LOGHANDLE_MAX];

static const char *event_code[] = {
    "mark",
    "fatal",
    "error",
    "warning",
    "normal",
    "notice",
    "info",
    "verbose",
    "check",
    "logic",
    "argh",
    "hmm",
    "func",
    "var",
    "io",
    "trace"
};

int logfilter(int logcode, const char *logmsg)
{   
    char time_str[LOGMSG_MAX];
    char date_str[LOGMSG_MAX];
    char year_str[LOGMSG_MAX];

    time_t log_time;
    struct tm *time_tm;

    int logclass;
    int loglevel;
    char *str_ptr;

    /* Decode log code */
    loglevel = logcode & 15;
    logclass = logcode & 240;

    /* Format timestamp */
    log_time = time(NULL);
    time_tm = localtime(&log_time);
    strftime(year_str,LOGMSG_MAX,"%G",time_tm);
    strftime(date_str,LOGMSG_MAX,"%m%d",time_tm);
    strftime(time_str,LOGMSG_MAX,"%H:%M:%S",time_tm);

    /* Replace eventual line feeds */
    while ((str_ptr=strchr(logmsg,'\n'))){
        *str_ptr = ' ';
    }

    /* Loop all loghandles and see if they handle this message */
    for (int id=0; id <= LOGHANDLE_MAX; id++){
        if ((loghandle[id].logdevice != NULL) &&        // Current loghandle is configured
            (loghandle[id].logclass & logclass) &&      // loghandle handles this class 
            (loghandle[id].loglevel >= loglevel))       // loghandle handles this level
            {               
                /* Format message for output */
                char outmsg[LOGMSG_MAX];
                char buf[LOGMSG_MAX];

                // Prefix format
                if (loghandle[id].logformat & SHOW_YEAR){
                    sprintf(buf,"%s ",year_str);
                    strcat(outmsg,buf);
                }
                if (loghandle[id].logformat & SHOW_DATE){
                    sprintf(buf,"%s ",date_str);
                    strcat(outmsg,buf);
                }
                if (loghandle[id].logformat & SHOW_TIME){
                    sprintf(buf,"%s ",time_str);
                    strcat(outmsg,buf);
                }

                strcat(outmsg,"[");

                if (loghandle[id].logformat & SHOW_ID){
                    sprintf(buf,"%i.",id);
                    strcat(outmsg,buf);
                }
                if (loghandle[id].logformat & SHOW_CLASS){
                    sprintf(buf,"%i.",logclass);
                    strcat(outmsg,buf);
                }
                if (loghandle[id].logformat & SHOW_LEVEL){
                    sprintf(buf,"%s",event_code[loglevel]);
                    strcat(outmsg,buf);
                }
                // Message
                snprintf(buf,sizeof(buf)-1,"] %s",logmsg);
                strncat(outmsg,buf,sizeof(outmsg)-strlen(outmsg)-1);
                
                /* Write message to logdevice */
                FILE *fout = fopen (loghandle[id].logdevice,"a");
                if (fout != NULL){
                    fprintf(fout,"%s\n",outmsg);
                    fclose(fout);
                }
                else
                    printf("loghandler FATAL: Could not write to logfile %s",loghandle[id].logdevice);
            }
    }
    return (0);
}

int loghandler_init(int id,
                    const char *logdevice,
                    int logclass, 
                    int loglevel,
                    int logformat)
{
    char msg[LOGMSG_MAX];
    
    // Check parameters
    if (id > LOGHANDLE_MAX) return(-1);
    if (logdevice == NULL) return(-1);
    FILE *fout = fopen (logdevice,"a");
    if (fout==NULL)
        return (-1);
    else
        fclose (fout);

    if (logformat < 0) logformat = DEFAULT_LOGFORMAT;
    if (logclass < 0) logclass = DEFAULT_LOGCLASS;
    if (loglevel < 0) loglevel = DEFAULT_LOGLEVEL;
    
    // Set config
    loghandle[id].logdevice = logdevice;
    loghandle[id].logformat = logformat;
    loghandle[id].logclass = logclass;
    loghandle[id].loglevel = loglevel;

    // Notify
    snprintf(msg,
             LOGMSG_MAX,
             "INIT::loghandle[%i] device[%s] format[%i] classfilter[%i] level[%i]",
             id,
             logdevice,
             logformat,
             logclass,
             loglevel);
    loghandler(logclass,D_CHECK,msg);
    return(0);
}

int loghandler_init(int id,const char *logdevice)
{
    return (loghandler_init(id,logdevice,-1,-1,-1));
}

int loghandler_setlevel(int id, int loglevel)
{
    loghandler(loghandle[id].logclass,
               D_CHECK,
               "loghandle[%i].setlevel %i",
               id,
               loglevel);
    
    loghandle[id].loglevel = loglevel;
    
    return(0);
}

int loghandler_getlevel(int id)
{
    return (loghandle[id].loglevel);
}

int loghandler_setclass(int id, int logclass)
{
    loghandle[id].logclass = logclass;

    return(0);
}

int loghandler_getclass(int id)
{
    return (loghandle[id].logclass);
}

void loghandler(int loglevel, int logclass, const char *msg, ...)
{   
    char logmsg[LOGMSG_MAX];
    int logcode;

    /* Combine class and level to logcode */
    logcode = loglevel | logclass;

    // Format message
    va_list list;
    va_start (list,msg);
    vsprintf (logmsg,msg,list);
    va_end (list);
    
    logfilter(logcode, logmsg);     
}

void logf(int logcode, const char *msg, ...)
{   
    char logmsg[LOGMSG_MAX];

    logcode |= MAIN_LOG;

    // Format message
    va_list list;
    va_start (list,msg);
    vsprintf (logmsg,msg,list);
    va_end (list);

    logfilter(logcode, logmsg);
}

void debugf(int logcode, const char *msg, ...)
{   
    char logmsg[LOGMSG_MAX];

    logcode |= DEBUG_LOG; // Add debug flag
    logcode |= MAIN_LOG;  // Temporary hack
 
    // Format message
    va_list list;
    va_start (list,msg);
    vsprintf (logmsg,msg,list);
    va_end (list);

    logfilter(logcode, logmsg);
}

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