popufare/busunit/passdb/pass_communication.c

/*
 * Copyright (c) 2019 Clementine Computing LLC.
 *
 * This file is part of PopuFare.
 * 
 * PopuFare is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * PopuFare 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 Affero General Public License for more details.
 * 
 * You should have received a copy of the GNU Affero General Public License
 * along with PopuFare.  If not, see <https://www.gnu.org/licenses/>.
 *
 */

#include <sys/socket.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/un.h>

#include <netinet/in.h>
#include <arpa/inet.h>

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <poll.h>
#include <time.h>

#include <zlib.h>

#include "../common/common_defs.h"
#include "../commhub/commhub.h"
#include "../commhub/client_utils.h"
#include "passdb.h"
#include "rules.h"
#include "rfid_decoder.h"

//----------GLOBAL STATE VARIABLES

int flush_in_progress = 0;  //This flag is used to tell if there is a flush in progress

time_t   last_sync_attempt = 0;  //Time of the last sync attempt in seconds since epoch
time_t  last_sync_ack = 0;  //Time of the last ack from the server (update, delete, or nop)

int   commhub_fd = -1;  //File descriptor of our connection to the comm hub
int  server_fd = -1;    //File descriptor of our connection to the sync server

int  zflush_in_progress = 0;
void   *zflush_data = NULL;
int  zflush_data_size = 0;
int   zflush_idx = 0;

time_t  last_piu_update = 0;  //Last PIU status update


pass_status real_pass_status = {0};

int update_piu_status_message(int busy)
{
    struct message_record outgoing;
    time_t now = time(NULL);
    struct tm t;
    
    char *status = "READY";
    
    int am_pm;
    int hour;
    
    if(busy)
    {
        status = "BUSY";    
    }
    else
    {  
        if( real_pass_status.flush_status == FLUSH_STATUS_APPLY )
        {
            status = "APPLY";
        }
        else if(real_pass_status.flush_status == FLUSH_STATUS_WRITE)
        {
            status = "SAVING";
        }
        else if( !rules_loaded() || 
            (real_pass_status.flush_status == FLUSH_STATUS_LEGACY) ||
            (real_pass_status.flush_status == FLUSH_STATUS_DOWNLOAD) ) 
        {
            status = "LOADING";
        }
        else if( !driver_stat.logged_in_driver )
        {
            status = "SEE DRIVER";
        }
    }
    
    if(commhub_fd >= 0)
    {
        localtime_r(&now, &t);    
        
        if( (t.tm_hour < 12) )
        {
            am_pm = 0;
            
            if(t.tm_hour == 0)
            {
                hour = 12;
            }
            else
            {
                hour = t.tm_hour;
            }
        }
        else
        {
            am_pm = 1;
            
            if(t.tm_hour == 12)
            {
                hour = 12;
            }
            else
            {
                hour = t.tm_hour - 12;
            }
        }
        
        format_piu_message(&outgoing, 0, 0, 0, "%d/%d %d:%02d %s %s", t.tm_mon + 1, t.tm_mday, hour, t.tm_min, am_pm?"PM":"AM", status);
        send_message(commhub_fd, &outgoing);
        
        if(real_pass_status.flush_status == FLUSH_STATUS_DOWNLOAD)
        {
            format_piu_message(&outgoing, 1, 0, 0, "Downloading %d%%", real_pass_status.progress_indicator);
            send_message(commhub_fd, &outgoing);
        }
        else if(real_pass_status.flush_status == FLUSH_STATUS_APPLY)
        {
            format_piu_message(&outgoing, 1, 0, 0, "Applying %d%%", real_pass_status.progress_indicator);
            send_message(commhub_fd, &outgoing);
        }
        else if(real_pass_status.flush_status == FLUSH_STATUS_WRITE)
        {
            format_piu_message(&outgoing, 1, 0, 0, "Saving Database");
            send_message(commhub_fd, &outgoing);
        }
        else
        {
            format_piu_message(&outgoing, 1, 0, 0, "");
            send_message(commhub_fd, &outgoing);
        }
    }
    
    return 0;
}

//This function attempts to connect to the pass server...
int connect_to_pass_server()
{
    int fd;
    int retval;
    struct sockaddr_in addr;

    fd = socket(PF_INET, SOCK_STREAM, 0);

    if(fd < 0)
        return -1;

    addr.sin_family = AF_INET;
    addr.sin_port = htons(PASS_SERVER_PORT);
    inet_aton(PASS_SERVER_IP, &addr.sin_addr);

    retval = connect(fd, (struct sockaddr *)&addr, sizeof(addr));

    if(retval < 0)
    {
        close(fd);
        return -2;
    }

  return fd;
}

int do_database_flush(passdb_context *ctx)
{
        int retval;
        
        //Detach from the current pass database
        detach_from_passdb(ctx);
        //Format a new database file...
        format_new_passdb();
        
        retval = attach_to_passdb(ctx);
        
        if( DB_FAIL(retval) )  //If we fail to attach to our new database
        {
            fprintf(stderr, "Error (%d) attaching to pass database during flush attempt\n", retval);  //report failure
            return retval;
        }
        else  //Otherwise, report success.
        {
            printf("Pass database flushed!\n");
            return 0;
        }
}

int send_query_message(int fd, passdb_context *ctx)
{
    char query[LINE_BUFFER_SIZE] = {0};
    int i, n;
    int retval;
    
    if(fd < 0)
        return -1;
    
    n = sprintf(query, "QUERY\t%llu\n", ctx->seq);

//    printf("Sending: \"%s\"\n", query);
    
    i = 0;
    
    while(i < n)
    {
        retval = send(fd, query + i, n - i, 0);
        
        if(retval <= 0)
            return -1;
            
        i += retval;
    }
    
    return 0;
}

int send_flushreq_message(int fd)
{
    char query[LINE_BUFFER_SIZE] = {0};
    int i, n;
    int retval;
    
    if(fd < 0)
        return -1;
    
    n = sprintf(query, "QUERY\t0\n");
    
//    printf("Sending: \"%s\"\n", query);
    
    i = 0;
    
    while(i < n)
    {
        retval = send(fd, query + i, n - i, 0);
        
        if(retval <= 0)
            return -1;
            
        i += retval;
    }
    
    return 0;
}

//  This function sends our local buspass state structure (real_pass_status) to other modules if either the force flag is set,
//or if it differs from the last one received from the IPC hub.
//
//  This function returns:
//
//    <  0  Failure in communication (IPC socket is down...)
//    == 0  No news to send (force was not set and our status has not changed)
//    == 1  News was successfully sent.
//
//  This is useful because often the next thing we want to do after sending a status update is update the display on the
//   PIU, but we only want to do that when the update represents a meaningful change which the user will notice (so as not
//   to flood that serial port with redundant change notifications).
//
int send_pass_state(int force)
{
    struct message_record outgoing_msg;
    int retval;

    //    Only actually perform the send if EITHER:  The force flag has been set, OR the status message we are sending
    //differs from the last status message we received from ourselves via the IPC hub (which should model what other
    //modules think out status currently is).
    if(force || memcmp(&real_pass_status, &pass_stat, sizeof(real_pass_status)))
    {
        prepare_message(&outgoing_msg, MAILBOX_PASS_STATUS, &real_pass_status, sizeof(real_pass_status));
        retval = send_message(commhub_fd,&outgoing_msg);

        return (retval < 0)?retval:1; 
    }
    
    return 0;
}

//  This function updates our local buspass state structure (real_pass_status) from the internal state of other data structures
//and using the two parameters (flush_status (see ../commhub/commhub.h for values) and a progress indicater (in percent),
//a copy of our local status to other modules if it differs from the last state (using the send_pass_state() function above).
int update_pass_state(int flush_status, int progress)
{
    
    real_pass_status.progress_indicator = 0;
    
    switch(flush_status)
    {
        case FLUSH_STATUS_DOWNLOAD:  //This means we're in the process of downloading a ZFLUSH dataset

            real_pass_status.flush_status = FLUSH_STATUS_DOWNLOAD;
            
            if(progress == 0)  //if no progress indicator number is supplied
            {
                if(zflush_data_size != 0)  //and it is possible to calculate
                {
                    //use our download count / expected size to calculate a percentage
                    real_pass_status.progress_indicator = (100 * zflush_idx) / zflush_data_size;  
                }
            }
            else    //if a progress indicator is supplied, simnply use it...
            {
                real_pass_status.progress_indicator = progress;
            }
            break;

        case FLUSH_STATUS_APPLY:  //In the case of APPLY, WRITE, or LEGACY, just take the progress number on faith
        case FLUSH_STATUS_WRITE:
        case FLUSH_STATUS_LEGACY:
            {
                real_pass_status.flush_status = flush_status;
                real_pass_status.progress_indicator = progress;
            }
            break;
    
        default:      //Otherwise, just let the other modules know we're feeling normal today...
            real_pass_status.flush_status = FLUSH_STATUS_NORMAL;
            break;
    }
    
    //inform other modules of any changes...
    return send_pass_state(0);
}

int do_zflush(passdb_context *ctx, void *data, int len);

//Cleanup after (or abort in progress) a ZFLUSH attempt
int zflush_cleanup()
{
    zflush_idx = 0;
    flush_in_progress = 0;
    zflush_in_progress = 0;
    zflush_data_size = 0;

    if(zflush_data)
    {
        free(zflush_data);
    }
    zflush_data = NULL;
    
    return 0;
}

int handle_pass_update_request(char *line, passdb_context *ctx, int sync)
{
    rider_record foo = {0};
    
    char buffer[LINE_BUFFER_SIZE];
    
    int input_idx = 0;
    int eol = 0;

    //Extract the first tab-delimited field from the input line...
    input_idx += get_field(buffer, line + input_idx, sizeof(buffer), &eol);
    
    //If that field is blank, then we ignore this line
    if( buffer[0] == '\0' )
    {
        return 0;
    }

    if( !strcasecmp(buffer, "UPDATE") )      //========================================== UPDATE
    {
        //------------------------------------------------------------------ seq
        if( eol )
        {
            fprintf(stderr, "UPDATE: Premature end of line!\n");
            return -1;
        }
    
        //Get the next field (this should be sequence number...)
        input_idx += get_field(buffer, line + input_idx, sizeof(buffer), &eol);
        
        foo.seq = strtoull(buffer, NULL, 10);

        if( foo.seq == 0 )
        {
            fprintf(stderr, "UPDATE: Blank or zero sequence number not allowed!\n");
            return -1;
        }

        //------------------------------------------------------------------ ID
        if( eol )
        {
            fprintf(stderr, "UPDATE: Premature end of line!\n");
            return -1;
        }
        
        //Get the next field (this should be Rider ID...)
        input_idx += get_field(buffer, line + input_idx, sizeof(buffer), &eol);
        
        foo.id = strtoull(buffer, NULL, 10);

        if( foo.id == 0 )
        {
            fprintf(stderr, "UPDATE: Blank or zero rider ID not allowed!\n");
            return -1;
        }
        
        //------------------------------------------------------------------ Magstripe
        if( eol )
        {
            fprintf(stderr, "UPDATE: Premature end of line!\n");
            return -1;
        }
        
        //Get the next field (this should be the Magstripe Value...)
        input_idx += get_field(foo.magstripe_value, line + input_idx, sizeof(foo.magstripe_value), &eol);
        
        //------------------------------------------------------------------ RFID
        if( eol )
        {
            fprintf(stderr, "UPDATE: Premature end of line!\n");
            return -1;
        }
        
        //Get the next field (this should be the RFID Value...)
        input_idx += get_field(foo.rfid_value, line + input_idx, sizeof(foo.rfid_value), &eol);
        
        //------------------------------------------------------------------ Rule Name
        if( eol )
        {
            fprintf(stderr, "UPDATE: Premature end of line!\n");
            return -1;
        }
        
        //Get the next field (this should be the Rule Name...)
        input_idx += get_field(foo.rule_name, line + input_idx, sizeof(foo.rule_name), &eol);
        
        //------------------------------------------------------------------ Rule Parameter
        if( eol )
        {
            fprintf(stderr, "UPDATE: Premature end of line!\n");
            return -1;
        }
        
        //Get the next field (this should be the Rule Parameter...)
        input_idx += get_field(foo.rule_param, line + input_idx, sizeof(foo.rule_param), &eol);
        
        //If we have extra fields, that's BAD NEWS!
        if( !eol )
        {
            fprintf(stderr, "UPDATE: Too many fields!\n");
            return -1;
        }
        
        //If everything else is okay, go ahead and update our local database
        last_sync_ack = time(NULL);    
        return update_rider(ctx, &foo, sync);  //returning the status of that operation
    
    }
    else if( !strcasecmp(buffer, "DELETE") )  //========================================== DELETE
    {
        //------------------------------------------------------------------ seq
        if( eol )
        {
            fprintf(stderr, "DELETE: Premature end of line!\n");
            return -1;
        }
    
        //Get the next field (this should be sequence number...)
        input_idx += get_field(buffer, line + input_idx, sizeof(buffer), &eol);
        
        foo.seq = strtoull(buffer, NULL, 10);

        if( foo.seq == 0 )
        {
            fprintf(stderr, "DELETE: Blank or zero sequence number not allowed!\n");
            return -1;
        }

        //------------------------------------------------------------------ ID
        if( eol )
        {
            fprintf(stderr, "DELETE: Premature end of line!\n");
            return -1;
        }
        
        //Get the next field (this should be Rider ID...)
        input_idx += get_field(buffer, line + input_idx, sizeof(buffer), &eol);
        
        foo.id = strtoull(buffer, NULL, 10);

        if( foo.id == 0 )
        {
            fprintf(stderr, "DELETE: Blank or zero rider ID not allowed!\n");
            return -1;
        }
    
        //If we have extra fields, that's BAD NEWS!
        if( !eol )
        {
            fprintf(stderr, "DELETE: Too many fields!\n");
            return -1;
        }
        
        //If everything else is okay, go ahead and update our local database
        last_sync_ack = time(NULL);    
        return delete_rider(ctx, &foo, sync);  //returning the status of that operation
    }
    else if( !strcasecmp(buffer, "FLUSH") )    //========================================== FLUSH
    {
        flush_in_progress = 1;
        
        if(update_pass_state(FLUSH_STATUS_LEGACY, 0) > 0)
        {
            update_piu_status_message(0);
        }
        
        fprintf(stderr, "Legacy Flush Requested!\n");
        last_sync_ack = time(NULL);    
        return do_database_flush(ctx); 
    }
    else if( !strcasecmp(buffer, "FLUSHDONE") )    //========================================== FLUSHDONE
    {
        flush_in_progress = 0;
        
        if(update_pass_state(FLUSH_STATUS_NORMAL, 0) > 0)
        {
            update_piu_status_message(0);
        }
        
        fprintf(stderr, "Legacy Flush Done!\n");
        last_sync_ack = time(NULL);    
        return 0;
    }
    else if( !strcasecmp(buffer, "ZFLUSH") )    //========================================== FLUSH
    {
        //------------------------------------------------------------------ seq
        if( eol )
        {
            fprintf(stderr, "ZFLUSH: Premature end of line!\n");
            return -1;
        }
    
        //Get the next field (this should be sequence number...)
        input_idx += get_field(buffer, line + input_idx, sizeof(buffer), &eol);
        
        zflush_data_size = strtoull(buffer, NULL, 10);
        
        zflush_data = malloc(zflush_data_size);
        
        if(zflush_data == NULL)
        {
            fprintf(stderr, "Can't malloc %d bytes for ZFLUSH!\n", zflush_data_size);
            return FAIL_MEM;
        }

        printf("ZFLUSH: Downloading %d bytes.\n", zflush_data_size);
        
        zflush_idx = 0;
        zflush_in_progress = 1;
        flush_in_progress = 1;

        if(update_pass_state(FLUSH_STATUS_DOWNLOAD, 0) > 0)  //Let update_pass_state() calculate our download percentage        
        {
            update_piu_status_message(0);
        }

        last_sync_ack = time(NULL);    
        return 0;
    }
    else if( !strcasecmp(buffer, "ZFLUSHDONE") )    //========================================== FLUSHDONE
    {
        fprintf(stderr, "ZFlush applying...\n");
        if(update_pass_state(FLUSH_STATUS_APPLY, 0) > 0)  //Mark that we're starting an apply operation
        {
            update_piu_status_message(0);
        }

        do_zflush(ctx, zflush_data, zflush_data_size);

        zflush_cleanup();
                
        if(update_pass_state(FLUSH_STATUS_NORMAL, 0) > 0)
        {
            update_piu_status_message(0);
        }

        fprintf(stderr, "ZFlush Done!\n");
        last_sync_ack = time(NULL);    
        return 0;
    }
    else if( !strcasecmp(buffer, "NOP") )      //========================================== NOP (this just updates ACK time)
    {
        last_sync_ack = time(NULL);    
        return 0;
    }
    else
    {
        fprintf(stderr, "Unrecognized command: %s\n", buffer);
        return -1;
    }
}

int do_zflush(passdb_context *ctx, void *data, int len)
{
    char line[LINE_BUFFER_SIZE] = {0};
    z_stream foo = {0};
    
    int zretval;
    int retval;
    int i,j,k;
    int nout;
    
    struct message_record incoming_msg;
    
    foo.zalloc = Z_NULL;
    foo.zfree = Z_NULL;
    foo.opaque = Z_NULL;
    
    foo.next_in = zflush_data;
    foo.avail_in = zflush_data_size;
    
    foo.next_out = (void *)line;
    foo.avail_out = sizeof(line);
    foo.total_out = 0;

//    printf("do_zflush(%p, %p, %d)\n", ctx, data, len);
    
    retval = inflateInit(&foo);
    
    if(retval != Z_OK)
    {
        fprintf(stderr, "inflateInit failed: Zlib error %d\n", retval);
        return FAIL_DATABASE;
    }    

    retval = do_database_flush(ctx);

    if( DB_FAIL(retval) )
    {
        fprintf(stderr, "Database failure during ZFLUSH while performing flush\n");
        return retval;
    }

    do
    {
        RESET_WATCHDOG();
        
        //Respond to PING messages from the supervisor process lest we get killed off too early...
        while(message_socket_status(commhub_fd, MSG_RECV) & MSG_RECV)
        {
            if(get_message(commhub_fd, &incoming_msg) >= 0)
            {
                process_message(&incoming_msg);    
            }
        }
        
        zretval = inflate(&foo, Z_NO_FLUSH);
        
        if( (zretval == Z_NEED_DICT) || (zretval == Z_DATA_ERROR) || (zretval == Z_MEM_ERROR) || (zretval == Z_STREAM_ERROR) )
        {
            fprintf(stderr, "Error inflating data: Zlib error %d\n", zretval);
            inflateEnd(&foo);
            return FAIL_DATABASE;
        }
        
        //The number of output bytes generated is the size of the buffer - number of free bytes
        nout = sizeof(line) - foo.avail_out;
//        printf("-- %d output bytes\n", nout);

        j = 0;
        
        //Scan through this buffer looking for EOL characters
        for(i=0; i < nout; i++)
        {
            if(line[i] == '\n')    //if we've found one
            {
                line[i] = '\0';    //make it a terminating nul
                
                
//                printf("ZFLUSH->%s\n", line + j);
                
                //handle our pass update
                #ifdef ZFLUSH_SLOW_BUT_SAFE
                    //In slow but safe mode, we msync() (or write()) the memory page containing each record after each update.
                    //This is hell on the flash, and it takes a long time, but it means that we cannot POSSIBLY write a lower
                    //sequence number record to the physical storage media before having physically written all previous
                    //sequence numbers in the batch.
                    retval = handle_pass_update_request(line + j, ctx, 1);  
                #else
                    //In fast mode, we apply all of our update to the memory window without calling msync() or write(), and then
                    //(see below) when we're done rewriting the mmap()'d window for the local database, then we make one call
                    //to msync() or write() and splat it all down to flash at once.  This gets us a better compression ratio
                    //on the large chunks of file (like the Cornell passes) which change infrequently and it produces less
                    //filesystem fragmentation, but it means that it is theoretically possible for a power event to cause a
                    //partial write to corrupt the local database (requiring a new flush).  That being said, when running on
                    //top of JFFS2, this should cause file truncation, which will be easily detectable and trigger another
                    //flush request next time the application comes up.
                    retval = handle_pass_update_request(line + j, ctx, 0);
                #endif
                
                if( DB_FAIL(retval) )
                {
                    inflateEnd(&foo);
                    fprintf(stderr, "Database failure during ZFLUSH while processing line \"%s\"\n", line + j);
                    return retval;
                }
                
                //mark the first character of the next line
                j = i + 1;
                
            }
        }
        
        //k will be equal to the number of leftover bytes
        k = i - j;

//        printf("-- i = %d j = %d k = %d\n", i, j, k);
        
        //copy those leftovers back to the beginning
        for(i = 0; i < k; i++)
        {
            line[i] = line[j + i];
        }
    
        //and update our output buffer structure
        foo.next_out = (void *)(line + k);
        foo.avail_out = sizeof(line) - k;
    
        if(foo.avail_out == 0)
        {
            fprintf(stderr, "Line too long in decompressed ZFLUSH data!\n");
            inflateEnd(&foo);
            return FAIL_DATABASE;
        }
        
        //  Update the other modules with our status (APPLY) and a progress indicator based on the amount of compressed data
        //read as a percentage of the total ZFLUSH data blob.
        if(update_pass_state(FLUSH_STATUS_APPLY, (foo.total_in * 100) / zflush_data_size) > 0)
        {
            update_piu_status_message(0);
        }
    
    } while(zretval != Z_STREAM_END);
        
    inflateEnd(&foo);

    //In fast mode, we have to ensure that we write our big block of changes back to secondary storage all at once
    #ifndef ZFLUSH_SLOW_BUT_SAFE
    
        if(update_pass_state(FLUSH_STATUS_WRITE, 0) > 0)  //Let the other modules know we're performing the final write...
        {
            update_piu_status_message(0);
        }
        
        fprintf(stderr, "Doing one-shot file write...\n");
    
        //  This resets the watchdog timer for a double-long timeframe (120 seconds these days...) allowing the write to be
        //slow as dirt (this is rarely needed, but if the flash was badly fragmented it can take some time to coalesce free
        //blocks and possibly perform some erase cycles.
        RESET_WATCHDOG_LONG(2);

        
        //  This calls msync() if we're working with a non-broken implementation of mmap() (i.e. non-jffs2) or write()
        //to take our updated state from RAM and save it to the underlying file.        
        sync_all_riders(ctx);
        
        fprintf(stderr, "Done.\n");
        
    #endif

    //    After completing a ZFLUSH operation, we want to hang up on the server (and reconnect asap).  The server should
    //also hang up on us after completing transmission of a ZFLUSH dataset.  This effectively clears the buffers going both
    //ways which prevents tha case where a high communication (or server-side database) lag causes two "QUERY  0" messages
    //to be issued in a row, the first one triggering (correctly) a ZFLUSH which will be completed, then the server will read
    //the second (now obsolete) "QUERY  0" message and respond to it with another (now just useless and annoying) ZFLUSH.

    close(server_fd);  //We just do a rude close...  The server does a proper shutdown(fd, 2), and the FIN will have reached
                        //us LONG before we execute this...
                        
    server_fd = -1;  //Mark the TCP connection to the server as dead so we flush buffers and restart the connection next
                        //time through the loop.

    return 0;
}


//callback handles MAILBOX_UPDATE_PASSES
message_callback_return handle_update_passes_message(struct message_record *msg, void *param)
{
    //flag our last sync attempt as NEVER
    last_sync_attempt = 0;
    
    return MESSAGE_HANDLED_CONT;    
}

//callback handles MAILBOX_FLUSH_PASSES
message_callback_return handle_flush_passes_message(struct message_record *msg, void *param)
{
    //We only want to allow a FLUSH_PASSES request to go through if the following conditions are met:
    if( (server_fd >= 0) &&   //1:  We have a connection to the server
        (tunnel_is_up()) &&   //2:  That connection is real (i.e. the SSH tunnel is in a known good state)
        (real_pass_status.flush_status == FLUSH_STATUS_NORMAL)  //3: we are not currently in the middle of doing a flush...
      )
    {
        send_flushreq_message(server_fd);
    }

    return MESSAGE_HANDLED_CONT;
}

//callback handles MAILBOX_STATUS_REQUEST
message_callback_return handle_status_request_message(struct message_record *msg, void *param)
{
    //  If we're responding to a status request message, we have to force a send even if it seems redundant because odds are
    //the requesting module just came on line and has no current status data for us.
    send_pass_state(1);

    return MESSAGE_HANDLED_CONT;
}

int reject_unknown_card(char *cred)
{
    struct message_record bill_msg;
    struct message_record user_msg;
    struct message_record rider_msg;
    
    format_piu_message(&rider_msg, 1, PIU_PRIORITY_FARE, PASSENGER_MESSAGE_DURATION, "%s %s", REJECT_STR, "UNKNOWN CARD");
    format_driver_message(&user_msg, LOGLEVEL_REJECT, "Unknown card");
    format_billing_message(&bill_msg, REJECT_STR, "UNKNOWN-CARD", "", "Unknown card", cred, 0, 0);
    
    if(commhub_fd >= 0)
    {
        send_message(commhub_fd, &bill_msg);
        send_message(commhub_fd, &user_msg);
        send_message(commhub_fd, &rider_msg);
        
        return 0;
    }
    else
    {
        return -1;
    }
}

#ifdef REJECT_IF_NO_DRIVER
    int reject_no_driver()
    {
        struct message_record user_msg;
        struct message_record rider_msg;
    
        format_piu_message(&rider_msg, 1, PIU_PRIORITY_FARE, PASSENGER_MESSAGE_DURATION, "%s", "SEE DRIVER");
        format_driver_message(&user_msg, LOGLEVEL_REJECT, "Not Logged In!");

        if(commhub_fd >= 0)
        {
            send_message(commhub_fd, &user_msg);
            send_message(commhub_fd, &rider_msg);
        
            return 0;
        }
        else
        {
            return -1;
        }
    }
#endif

message_callback_return handle_token_mag_message(struct message_record *msg, void *param)
{
    int idx;
    char cred[LINE_BUFFER_SIZE] = {0};
    passdb_context *ctx = (passdb_context *)param;
    
    if(!ctx)
        return MESSAGE_HANDLED_CONT;
    
    update_piu_status_message(1);
    
    #ifdef REJECT_IF_NO_DRIVER
        if( (driver_stat.logged_in_driver <= 0) || (stop_stat.paddle <= 0) )
        {
            reject_no_driver();
            return MESSAGE_HANDLED_CONT;
        }
    #endif
        
    idx = smart_find_mag(ctx, (char *)msg->payload, cred);
    
    if(idx < 0)
    {
        reject_unknown_card(cred);        
    }
    else
    {
        process_rider(ctx, idx, cred);
    }

    return MESSAGE_HANDLED_CONT;
}

message_callback_return handle_token_rfid_message(struct message_record *msg, void *param)
{
    int idx;
    char cred[LINE_BUFFER_SIZE] = {0};
    passdb_context *ctx = (passdb_context *)param;
    
    if(!ctx)
        return MESSAGE_HANDLED_CONT;
        
    update_piu_status_message(1);

    #ifdef REJECT_IF_NO_DRIVER
        if( (driver_stat.logged_in_driver <= 0) || (stop_stat.paddle <= 0) )
        {
            reject_no_driver();
            return MESSAGE_HANDLED_CONT;
        }
    #endif

    idx = smart_find_rf(ctx, (char *)msg->payload, cred);
    
    if(idx < 0)
    {
        reject_unknown_card(cred);        
    }
    else
    {
        process_rider(ctx, idx, cred);
    }

    return MESSAGE_HANDLED_CONT;
}

message_callback_return update_anti_passback_cache(struct message_record *msg, void *param)
{
    apb_flush_if_needed();
    return MESSAGE_HANDLED_CONT;
}

message_callback_return handle_rule_call(struct message_record *msg, void *param)
{
    process_driver_rulecall( (driver_rulecall *)msg->payload );
    return MESSAGE_HANDLED_CONT;
}

void maintain_ipc_hub_connect(char *progname)
{
    struct message_record outgoing_msg;

    if(commhub_fd < 0)  //if we have no connection to the communication hub
    {
        commhub_fd = connect_to_message_server(progname);  //try and get one
            
//        printf("commhub_fd = %d\n", commhub_fd);
            
        if(commhub_fd >= 0)  //if it worked
        {
            //Subscribe to the command mailboxes we act on
            prepare_message(&outgoing_msg, MAILBOX_SUBSCRIBE, MAILBOX_TOKEN_MAG, strlen(MAILBOX_TOKEN_MAG));
            send_message(commhub_fd,&outgoing_msg);  
                
            prepare_message(&outgoing_msg, MAILBOX_SUBSCRIBE, MAILBOX_TOKEN_RFID, strlen(MAILBOX_TOKEN_RFID));
            send_message(commhub_fd,&outgoing_msg);  
                
            prepare_message(&outgoing_msg, MAILBOX_SUBSCRIBE, MAILBOX_FLUSH_PASSES, strlen(MAILBOX_FLUSH_PASSES));
            send_message(commhub_fd,&outgoing_msg);  
                
            prepare_message(&outgoing_msg, MAILBOX_SUBSCRIBE, MAILBOX_UPDATE_PASSES, strlen(MAILBOX_UPDATE_PASSES));
            send_message(commhub_fd,&outgoing_msg);
                
            prepare_message(&outgoing_msg, MAILBOX_SUBSCRIBE, MAILBOX_RULE_CALL, strlen(MAILBOX_RULE_CALL));
            send_message(commhub_fd,&outgoing_msg);
                
            //Subscribe to the relevant status management mailboxes
            subscribe_to_default_messages(commhub_fd);
                            
            //Request updated status information...
            prepare_message(&outgoing_msg, MAILBOX_STATUS_REQUEST, "", 0);    
            send_message(commhub_fd,&outgoing_msg);
        }
    }
}

int main(int argc, char **argv)
{
    struct pollfd fds[2];
    int nfds = 0;
    int poll_return = 0;
    int read_return = 0;
    
    int i;

    struct message_record incoming_msg;

    char input_line[LINE_BUFFER_SIZE] = {0};
    int input_idx = 0;
    int checked_idx = 0;

    passdb_context ctx = {0};
    
    //------------------

    configure_signal_handlers(argv[0]);
    maintain_ipc_hub_connect(argv[0]);
    
    read_return = attach_to_passdb(&ctx);
    
    if( read_return < 0 )
    {
        fprintf(stderr, "Database is missing or corrupt.  Attempting to format new database.\n");
        read_return = format_new_passdb();
        
        if( read_return < 0 )
        {
            fprintf(stderr, "Database cannot be created.  Aborting!\n");
            return -1;
        }
        else
        {
            read_return = attach_to_passdb(&ctx);
            
            if( read_return < 0 )
            {
                fprintf(stderr, "New database is ALSO missing or corrupt.  Aborting.\n");
                return -1;
            }
        }
    }

    //Register our default keep-up-with-system status callbacks
    register_system_status_callbacks();
    
    //Add our module-specific callbacks
    register_dispatch_callback(MAILBOX_UPDATE_PASSES, CALLBACK_USER(1), handle_update_passes_message, NULL);
    register_dispatch_callback(MAILBOX_FLUSH_PASSES, CALLBACK_USER(2), handle_flush_passes_message, NULL);
    register_dispatch_callback(MAILBOX_STATUS_REQUEST, CALLBACK_USER(3), handle_status_request_message, NULL);
    register_dispatch_callback(MAILBOX_TOKEN_RFID, CALLBACK_USER(4), handle_token_rfid_message, &ctx);
    register_dispatch_callback(MAILBOX_TOKEN_MAG, CALLBACK_USER(5), handle_token_mag_message, &ctx);
    register_dispatch_callback(MAILBOX_RULE_CALL, CALLBACK_USER(6), handle_rule_call, &ctx);

    //Handle status updates which require us to check expiration of the anti-passback cache
    register_dispatch_callback(MAILBOX_GPS_STATUS, CALLBACK_USER(6), update_anti_passback_cache, NULL);
    register_dispatch_callback(MAILBOX_STOP_STATUS, CALLBACK_USER(7), update_anti_passback_cache, NULL);
    
    while( exit_request_status == EXIT_REQUEST_NONE )
    {
        time_t now = time(NULL);
        
        RESET_WATCHDOG();
        
        maintain_ipc_hub_connect(argv[0]);
        
        if( (now - last_piu_update) > 0)
        {
            update_piu_status_message(0);
            last_piu_update = now;
        }
        
        if(server_fd < 0)  //If we don't have a connection to the sync server...
        {
            if( (now - last_sync_attempt) > DEFAULT_CONNECT_RETRY )  //See if it is time to try again
            {
                if( tunnel_is_up() )          //and if the tunnel thinks it is up
                {
                     server_fd = connect_to_pass_server();    //if so, try again...
           
                     if(server_fd >= 0)  //if it worked
                     {
                         input_idx = 0;  //reset our buffer index
                         last_sync_attempt = 0;
                         
                         zflush_cleanup();;
                     }
                     else
                     {
                         last_sync_attempt = now;
                     }
                }
            }
        }

        if(!rules_loaded())
        {
            load_rules(RULES_FILE);
        }
        
        if(rfid_pattern_loaded() <= 0)
        {
            load_rfid_decode_patterns(RFID_PATTERN_FILE);
        }
        
        if(hup_request_status)
        {
            hup_request_status = 0;
            unload_rules();
            load_rules(RULES_FILE);
            load_rfid_decode_patterns(RFID_PATTERN_FILE);
        }
        
        nfds=0;
        
        if(server_fd >= 0)
        {
            fds[nfds].fd = server_fd;
            fds[nfds].events = POLLIN;
            
            if( (now - last_sync_attempt) > DEFAULT_PASS_SYNC_RETRY )
            {
//                printf("We want to sync...\n");
                fds[nfds].events |= POLLOUT;
            }
            
            nfds++;
        }
        
        if(commhub_fd >= 0)
        {
            fds[nfds].fd = commhub_fd;
            fds[nfds].events = POLLIN;
            
            nfds++;
        }

        
        
        if(nfds > 0)
        {
            poll_return = poll(fds, nfds, POLL_TIMEOUT);
        }
        else
        {
            usleep(POLL_TIMEOUT * 1000);
            poll_return = 0;
        }

        if(poll_return <= 0)
        {
            continue;
        }
        
        for(i=0; i < nfds; i++)
        {
            if( fds[i].fd == server_fd )
            {
                
                if(fds[i].revents & POLLIN)  //If we just got some input...
                {
                    if(zflush_in_progress)  //And we're in the middle of downloading ZFLUSH data
                    {
                        //Read it into our ZFLUSH buffer                    
                        read_return = recv(fds[i].fd, zflush_data + zflush_idx, zflush_data_size - zflush_idx, 0);
                    
                        //If the socket has closed politely (0), or had an error other than EINTR...
                        if( (read_return == 0) || ((read_return < 0) && (errno != EINTR)) )
                        {
                            printf("Lost touch with server.  This may be OK if we just finished downloading ZFLUSH data\n");
                            close(server_fd);
                            server_fd = -1;
                            break;
                        }
                        else
                        {
                            if(read_return > 0)  //Otherwise, if we got some real data
                            {
                                zflush_idx += read_return;  //advance our download pointer
                                
                                //We want to let the update_pass_state() function compute our progress bar...                                
                                update_pass_state(FLUSH_STATUS_DOWNLOAD, 0);
                                update_piu_status_message(0);
                                
                                last_sync_attempt = now;  //remember our last sync time
                                
                                if(zflush_idx == zflush_data_size)  //if we've got the whole shebang...
                                {
                                    //Flag that we're done downloading zflush blob and returning to command mode...
                                    zflush_in_progress = 0;  

                                    //  We don't have to do anything else about this, because the next thing we will hear
                                    //from the server is ZFLUSHDONE which will cause us to apply our downloaded zflush data.
                                }
                            }    
                        }
                    }
                    else  //If we are not in the middle of a ZFLUSH
                    {
                        read_return = recv(fds[i].fd, input_line + input_idx, sizeof(input_line) - input_idx, 0);
                    
                        //If the socket has closed politely (0), or had an error other than EINTR...
                        if( (read_return == 0) || ((read_return < 0) && (errno != EINTR)) )
                        {
                            printf("Lost touch with server.\n");
                            close(server_fd);
                            server_fd = -1;
                            break;
                        }
                        else
                        {
                            if(read_return > 0)    //and we got some real data
                            {
                                input_idx += read_return;  //advance our input index
                        
                                do      //loop through the data we've received...
                                {
                                    if(zflush_in_progress)  //if we have begun a ZFLUSH at some point,
                                    {
                                        if(input_idx >= zflush_data_size)
                                        {
                                            int j,k;
                                            
                                            memcpy(zflush_data, input_line, zflush_data_size);
                                            zflush_idx = zflush_data_size;
                                            zflush_in_progress = 0;
                                            
                                            k = input_idx - zflush_data_size;
                                            
                                            for(j = 0; j < k; j++)
                                            {
                                                input_line[j] = input_line[j + zflush_data_size];
                                            }
                                            
                                            input_idx = j;
                                            checked_idx = 0;
                                            
                                        }
                                        else
                                        {
                                            //    Steal the rest of our input buffer and tack it on to the beginning of the zflush
                                            //buffer.  We do this because otherwise we'd have the beginning of the zflush data blob
                                            //sitting around collecting dust in the line buffer and we'd download the rest into the
                                            //zflush buffer and be unable to process it because the beginning would still be
                                            //sitting around in this other buffer.
                                        
                                            memcpy(zflush_data, input_line, input_idx);  
                                        
                                            zflush_idx = input_idx;    //advance the zflush buffer index appropriately
                                            checked_idx = input_idx = 0;  //clear our line buffer index as it is now empty

                                            last_sync_attempt = now;  //mark our last sync time as now
                                            //printf("Added %d leftover bytes to zflush_data\n", input_idx);
                                            break;  //break out of the do loop since we're done with our input buffer
                                        }
                                        
                                    }
                                
                                
                                    //Advance until we either hit the end of the buffer, or we hit a line-terminator
                                    while(checked_idx < input_idx)
                                    {
                                        if( (input_line[checked_idx] == '\r') || (input_line[checked_idx] == '\n') )
                                        {
                                            break;
                                        }
                                        else
                                        {
                                            checked_idx++;
                                        }
                                    }
                                
                                    //If we didn't hit the end of the input... (meaning we got a whole line...)
                                    if(checked_idx != input_idx)
                                    {
                                        int j,k;
                                    
                                        //Null terminate the line we got as a string...
                                        input_line[checked_idx] = '\0';
                                    
                                        //printf("Got Command \"%s\"\n", input_line);

                                        if( handle_pass_update_request(input_line, &ctx, 1) < 0 )
                                        {
                                   //  printf("Command Failed: \"%s\"\n", input_line);
                                        }
                                        else
                                        {
                                            real_pass_status.last_ack_time = now;
                                        }                             
 
                                        last_sync_attempt = now;      //remember this server contact time
                                        real_pass_status.last_sync_time = now;    //add it to our passdb status
                                        send_pass_state(0);        //update other modules if this represents a change
 
                                        //    Now that we've done that, we can bump the rest of characters to the beginning 
                                        //of the next line...
                                        k = input_idx - (checked_idx + 1);
                                    
                                        //copy those characters the the beginning of the buffer...
                                        for(j=0; j < k; j++)
                                        {
                                            input_line[j] = input_line[j + checked_idx + 1];
                                        }
                                    
                                        input_idx = j;    //Move the index to point to the next free byte in the buffer
                                        checked_idx = 0;  //  Move the 'checked' index to the beginning so that next time
                                                                //we start counting index 0 as the beginning of the next line when
                                                                //it is time to start scanning for EOL.
                                  }
                                
                                  //    If we have hit an overflow condition such that our buffer is full and no newline 
                                  //has been received, we want to hang up on the server and try again because something is
                                  //seriously borked...
                                  if(input_idx == sizeof(input_line))
                                  {
                                      fprintf(stderr, "Input overrun from server (line too long).\n");
                                      close(server_fd);
                                      server_fd = -1;
                                      break;
                                  }
                            
                                } while(checked_idx < input_idx);  //  While we have unchecked data (that we have yet to check
                                                                        //for containing an end-of-line.
                            }
                        }
                    }    
                }
                else  //Be sure we process all input before closing a remotely closed socket...
                {
                    //If we've lost connection, break this loop and poll all over again
                    if(fds[i].revents & (POLLERR | POLLHUP | POLLNVAL))
                    {
                        printf("Lost touch with server.\n");
                        close(server_fd);
                        server_fd = -1;
                        break;
                    }
                }
                
                if(fds[i].revents & POLLOUT)  //If we have flagged that we intend to send a query and poll says it's OK...
                {
//                    printf("Trying to write to server...\n");

                    if(real_pass_status.flush_status == FLUSH_STATUS_NORMAL)
                    {
                        send_query_message(server_fd, &ctx);
                        real_pass_status.last_sync_time = now;
                        send_pass_state(0);
                    }
                    else
                    {
                        printf("Skipping query opportunity because we are mid-flush.\n");
                    }
                                        
                    //and then update our last sync attempt time
                    last_sync_attempt = now;
                }
                
            }
            else if( fds[i].fd == commhub_fd )
            {  
                //If we've lost connection, break this loop and poll all over again
                if(fds[i].revents & (POLLERR | POLLHUP | POLLNVAL))  
                {
                    close(commhub_fd);
                    commhub_fd = -1;
                    break;
                }
                
                if(fds[i].revents & POLLIN)
                {
//                    printf("Trying to read from hub...\n");
                    read_return = get_message(commhub_fd, &incoming_msg);
                
                    if( read_return < 0 )
                    {
                        close(commhub_fd);
                        commhub_fd = -1;
                        break;
                    }
                
                    process_message(&incoming_msg);  //This passes the received message through the callback list
                    
                }
                
            }
        }  
    }

    printf("Detatching from Pass Database\n");
    detach_from_passdb(&ctx);
    
    printf("Closing connections\n");
    if(server_fd >= 0)
    {
        close(server_fd);
        server_fd = -1;
    }

    if(commhub_fd >= 0)
    {
        close(commhub_fd);
        server_fd = -1;
    }

    printf("Goodbye.\n");

    return 0;
}