/*
    ELAPI

    Implemenation of the syslog sink.

    Copyright (C) Dmitri Pal <dpal@redhat.com> 2009

    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 3 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, see <http://www.gnu.org/licenses/>.
*/


#include <stdio.h>
#include <errno.h>
#include <malloc.h>
#include <syslog.h>
#include "elapi_sink.h"
#include "elapi_collection.h"
#include "elapi_debug.h"
#include "elapi_util.h"
#include "elapi_ini.h"

/* Global variable - instance */
static int instance = 0;

/* FIXME - this should be taken from the config.h generated by autotools */
#define SYSLOG_RETRY    60
/* 
#define SYSLOG_AUDIT_CONFIG  "/etc/elapi/syslog_defaults.conf"
#define SYSLOG_AUDIT_DIR     "/etc/elapi/syslog_defaults.d"
*/
#define SYSLOG_AUDIT_CONFIG  "/home/dpal/IPA/Code/elapi/etc/syslog_defaults.conf"
#define SYSLOG_AUDIT_DIR     "/home/dpal/IPA/Code/elapi/etc/syslog_defaults.d"


/* FIXME there is currently no code 
 * to make sure we do not call syslog functions from multiple dispatchers.
 * We probably should create a mutex at the load of the library and
 * set a flag when the init function is called the first time
 * and not call the openlog any more times.
 * But I guess syslog can deal with this internally.
 */ 


struct syslog_event {
    struct serial_data sd;
    int priority;
};


/* Default conmfiguration for syslog */
struct syslog_conf {    
    int option;
    int facility;
    int level;
    char *ident;
};

/* Internal function to intialize configuration */   
static int init_config(struct data_descriptor *dblock) 
{
    struct syslog_conf *conf_data;
    struct collection_item *config_from_file = (struct collection_item *)(NULL);
    int found = 0;
    int *option_cfg = (int *)(NULL);
    int *facility_cfg = (int *)(NULL);
    int *level_cfg = (int *)(NULL);
    char *ident_cfg = NULL;
    int error;

    DEBUG_STRING("init_config","Entry");

    /* Allocate configuration data */
    conf_data = (struct syslog_conf *)(malloc(sizeof(struct syslog_conf)));
    if(conf_data == (struct syslog_conf *)(NULL)) return errno;

    /* Read configuration from the configuration file if any */
    (void)config_to_collection(dblock->appname, SYSLOG_AUDIT_CONFIG, SYSLOG_AUDIT_DIR, &config_from_file); 
    
    conf_data->option = LOG_ODELAY;
    conf_data->facility = LOG_USER;
    conf_data->level = LOG_INFO;
    conf_data->ident = NULL;

    DEBUG_NUMBER("Option",conf_data->option);
    DEBUG_NUMBER("Facility",conf_data->facility);
    DEBUG_NUMBER("Level",conf_data->level);
    DEBUG_STRING("Identity",conf_data->ident);

    /* Update defaults with settings from the file */
    error = get_value_from_config((void *)(&option_cfg),ELAPI_TYPE_INTEGER, INI_DEFAULT_SECTION,"option",config_from_file);
    if(error != EOK) {
        /* There is fundamentally something wrong */
        DEBUG_NUMBER("Attempt to get option returned error",error); 
        free((void *)(conf_data));       
        return error; 
    }

    /* Get the value */
    if(option_cfg != (int *)(NULL)) {
        conf_data->option = *option_cfg;
        free((void *)(option_cfg));
    } 

    error = get_value_from_config((void *)(&facility_cfg),ELAPI_TYPE_INTEGER, INI_DEFAULT_SECTION,"facility",config_from_file);
    if(error != EOK) {
        /* There is fundamentally something wrong */
        DEBUG_NUMBER("Attempt to get option returned error",error);        
        free((void *)(conf_data));       
        return error; 
    }

    /* Get the value */
    if(facility_cfg != (int *)(NULL)) {
        conf_data->facility = *facility_cfg;
        free((void *)(facility_cfg));
    } 

    error = get_value_from_config((void *)(&level_cfg),ELAPI_TYPE_INTEGER, INI_DEFAULT_SECTION,"level",config_from_file);
    if(error != EOK) {
        /* There is fundamentally something wrong */
        DEBUG_NUMBER("Attempt to get option returned error",error);        
        free((void *)(conf_data));       
        return error; 
    }

    /* Get the value */
    if(level_cfg != (int *)(NULL)) {
        conf_data->level = *level_cfg;
        free((void *)(level_cfg));
    } 
        
    error = get_value_from_config((void *)(&ident_cfg),ELAPI_TYPE_STRING, INI_DEFAULT_SECTION,"identity",config_from_file);
    if(error != EOK) {
        /* There is fundamentally something wrong */
        DEBUG_NUMBER("Attempt to get option returned error",error);        
        free((void *)(conf_data));       
        return error; 
    }

    /* Get the value */
    if(ident_cfg != (char *)(NULL)) {
        conf_data->ident = ident_cfg;
    } 


    DEBUG_NUMBER("Option (after conf file):",conf_data->option);
    DEBUG_NUMBER("Facility (after conf file):",conf_data->facility);
    DEBUG_NUMBER("Level (after conf file):",conf_data->level);
    DEBUG_STRING("Identity (after conf file):",conf_data->ident);

    dblock->config = (void *)(conf_data);

    openlog(conf_data->ident,conf_data->option,conf_data->facility);
    instance++;
    DEBUG_NUMBER("syslog instance",instance);

    DEBUG_STRING("init_config","Entry");
    return EOK;
}

/***** Standard functions each facility has to provide *****/
/* Initialize facility - open files, establish connnectons, etc... */
static int syslog_sink_init(struct data_descriptor *dblock)
{
    struct syslog_event *event_storage;
    int error;

    DEBUG_STRING("syslog_sink_init","Entry");

    /* Prepare the block where the format function will store its data */
    errno = 0;
    dblock->internal_data = NULL;
    event_storage = (struct syslog_event *)(malloc(sizeof(struct syslog_event)));
    if(event_storage == (struct syslog_event *)(NULL)) return errno;

    event_storage->sd.buffer = NULL;
    event_storage->sd.size = 0;
    event_storage->sd.length = 0;
    event_storage->sd.nest_level = 0;

    dblock->internal_data = (void *)(event_storage);
    
    /* Prepare the configuration data block */
    if((error = init_config(dblock))) {
        DEBUG_NUMBER("Failed to init config",error);
        free(dblock->internal_data);
        dblock->internal_data = NULL;        
        return error;
    }

    DEBUG_NUMBER("DBLOCK in init",dblock);
    DEBUG_NUMBER("internal data in init",dblock->internal_data);

    DEBUG_STRING("syslog_sink_init","Exit");
    return EOK;
}


/* Formatting calback */ 
static int syslog_sink_format(struct data_descriptor *dblock,
                              char *format_str,
                              struct collection_item *event)
{
    struct syslog_event *event_storage;
    struct syslog_conf *config;
    struct collection_item *item;
    int error = EOK;

    DEBUG_STRING("syslog_sink_format","Entry");
    DEBUG_NUMBER("DBLOCK in format",dblock);
    DEBUG_NUMBER("internal data in format",dblock->internal_data);

    event_storage = (struct syslog_event *)(dblock->internal_data);
    config = (struct syslog_conf *)(dblock->config);

    event_storage->priority = config->level | config->facility;

    /* Get Priority */
    error = get_item(event,"priority",ELAPI_TYPE_INTEGER,ELAPI_TRAVERSE_ONELEVEL, &item);
    if(error) {
        DEBUG_NUMBER("Failed to get item from collection",error);
        /* Fall through */
    } else if((item != (struct collection_item *)(NULL)) && 
              (item->type == ELAPI_TYPE_INTEGER)) 
                event_storage->priority = *((int *)(item->data));
   

    if(format_str != NULL) {
        /* Use format string */
        DEBUG_STRING("Using format:",format_str);
        error = serialize_with_format(event,format_str,(void *)(&(event_storage->sd)));
    }
    else {
        /* Traverse collection */
        DEBUG_STRING("Using default serialization callback","");
        error = traverse_collection(event,ELAPI_TRAVERSE_DEFAULT | ELAPI_TRAVERSE_END ,serialize,(void *)(&(event_storage->sd)));
    }
    if(error) {
        DEBUG_NUMBER("Serialization returned error",error);
        return error;
    }

    DEBUG_STRING("syslog_sink_format","Exit");
    return EOK;
}


/* Cleanup per event internal data after a failure */
static void syslog_sink_cleanup(struct data_descriptor *dblock)
{
    struct syslog_event *event_storage;
    struct syslog_conf *config;

    DEBUG_STRING("syslog_sink_cleanup","Entry");

    event_storage = (struct syslog_event *)(dblock->internal_data);
    config = (struct syslog_conf *)(dblock->config);

    if(event_storage->sd.buffer != NULL) {
        free(event_storage->sd.buffer);
        event_storage->sd.buffer = NULL;
        event_storage->sd.size = 0;
        event_storage->sd.length = 0;
        event_storage->sd.nest_level = 0;
        event_storage->priority = config->level | config->facility;
    }

    DEBUG_STRING("syslog_sink_cleanup","Exit");
}

/* Close facility */ 
static void syslog_sink_close(struct data_descriptor *dblock)
{
    struct syslog_conf *config;

    DEBUG_STRING("syslog_sink_close","Entry");

    if(dblock->internal_data != NULL) {
        syslog_sink_cleanup(dblock);
        free(dblock->internal_data);
        dblock->internal_data=NULL;
    }

    if(dblock->config != NULL) {
        config = (struct syslog_conf *)(dblock->config);
        if(config->ident != NULL) free(config->ident);
        free(dblock->config);
        dblock->config=NULL;
    }

    closelog();
    DEBUG_STRING("Closed syslog","");
    if(instance) instance--;
    DEBUG_NUMBER("syslog instance",instance);
    DEBUG_STRING("syslog_sink_close","Exit");
}


/* Logging calback */ 
static int syslog_sink_submit(struct data_descriptor *dblock)
{
    struct syslog_event *event_storage;

    DEBUG_STRING("syslog_sink_submit","Entry");
    DEBUG_NUMBER("DBLOCK in submit",dblock);
    DEBUG_NUMBER("internal data in submit",dblock->internal_data);

    event_storage = (struct syslog_event *)(dblock->internal_data);
   
    DEBUG_STRING("OUTPUT:",event_storage->sd.buffer);

    syslog(event_storage->priority, "%s", event_storage->sd.buffer);

    syslog_sink_cleanup(dblock);

    DEBUG_STRING("syslog_sink_submit","Exit");
    return EOK;
}

/* Return a filled in structure */
void get_sink_info(struct sink_capability *sink_cpb_block)
{
    DEBUG_STRING("get_sink_info","Entry");

    sink_cpb_block->retry_interval = SYSLOG_RETRY;
    sink_cpb_block->flags = SINK_FLAG_LOAD_SINGLE;
    sink_cpb_block->instance = instance;
    sink_cpb_block->init_cb = syslog_sink_init;
    sink_cpb_block->cleanup_cb = syslog_sink_cleanup;
    sink_cpb_block->format_cb = syslog_sink_format;
    sink_cpb_block->submit_cb = syslog_sink_submit;
    sink_cpb_block->close_cb = syslog_sink_close;

    DEBUG_STRING("get_sink_info","Exit");    
}