MBSE BBS Programs - mbtask - MBSE BBS Taskmanager.

Last update 23-Mar-2002

mbtask - MBSE BBS Taskmanager

Sysopsis.

mbtask

Description.

mbtask is the taskmanager for the whole MBSE BBS system. This deamon keeps track of all client actions, does the logging for the clients, does database locking, authorizes clients, set/resets users "do not disturb flags", sends and receives chat messages, keeps track of Zone Mail Hour, the status of the mail and files in the outbound, and the BBS open/close status. Communication between mbsed and the client programs is done via Unix Datagram sockets. The protocol used to communicate between mbtask and the clients is explained later. This daemon also watches the semafore directory for some special files. It also starts programs when they are needed. The very first time mbtask is started it creates a default config.data and task.data, the main configuration and task configuration files. Then it calls mbsetup init to build the default databases. mbtask should be started at system boot so the bbs system will start working. The init script that is installed on your system will do that.
After startup and initalization mbtask runs internally once per second forever. If there is nothing to do then this time will slowly increase upto 5 seconds. This time will be reset to one second as soon as there is work to be done. The actual work is to check a number of external and internal semafore's and act on these. But before any program is started a number of things are checked:

Check the system's load average. If it is too busy the processing of background tasks is suspended until your system load drops. The default setup is set at 1.50 but you can change that with mbsetup. Experience will learn what the best value will be and I need some feedback on that.

The UPS semafore upsalarm will be checked. This means that the system is running on battery power and no new jobs are started.
The UPS semafore upsdown will be checked. This is the fatal one, if this one exists mbtask will try to stop all current running jobs. If there are no jobs left running then mbtask will stop itself. The upsdown semafore means that the system will shutdown and power off, that's why it's fatal and there is no way back.

The status of the bbs will be checked, is it open or closed. If it is closed, no jobs will be started.
The Zone Mail Hour is checked. If ZMH begins the semafore's zmh is created. If ZMH ends the semafore zmh is removed.
Each twenty seconds a ping is send to the IP addresses defined with mbsetup to check if the internet can be reached. If both ping addresses fail, it is assumed that the internet can't be reached. After a status change, the outbound will be scanned.
Scan the mailer outbound for work. This builds a list of nodes with mail in the outbound and sets the necessary flags on nodes who may be called. If a node needs to be called, mbtask will spawn mbcico to call this node. The number of free modem and ISDN ports and the maximum number of TCP/IP sessions and already registered sessions, determine howmany sessions will be started. The sessions will be started at intervals of 20 seconds. It will also set a time when something will change for a node, ie. a zone mail hour is reached, or a mail window for a node with Txx flags is reached. Internally this scheduler runs at the UTC clock because Fidonet has all times defined in UTC.
Each new minute the timestamp of semafore mbtask.last is updated so that you can check that mbtask is running. Also each minute is checked if the system configuration files are changed, is so they are reloaded. There is no need to stop and start mbtask if you made changes to the system configuration. Then all kind of internal semafore's will be checked. The commands that are executed have default values, but they can be changed wit mbsetup. The commands can be scripts as well. The checks and actions are:

Semafore Speed Tasktype Depends on Job to run

mailout Fast mbfido Max. 1 mbfido task mbfido scan web -quiet

mailin Fast mbfido Max. 1 mbfido task mbfido tic toss web -quiet

newnews Fast mbfido Max. 1 mbfido task mbfido news web -quiet

mbindex Fast mbindex No other tasks mbindex -quiet and if exist: goldnode

msglink Fast mbfido No other tasks mbmsg link -quiet

reqindex Fast mbfile No other tasks mbfile index -quiet

scanout Slow call Only 1 call task mbcico -r1

The Fast and Slow values mean: Fast is each second, Slow is check each 20 seconds. As you can see, the system will not do too much at the same time. Jobs like compiling new nodelists or create file request indexes have a very low priority. Because this daemon checks the semafore's each second it responds much better that the old scripts running on the cron daemon. The system will be expanded so that more outgoing calls will be done at the same time, ie. ISDN and analogue calls, and if they are present internet calls, will be made at the same time.
The mbtask program keeps also track of a unique number generator, this is just a simple counter that is increased each time it is asked for a new number. It will take years for the numbers to repeat. Even if the status file is lost the chance that numbers are repeated on your system are almost zero. The first time the counter is initialized it is set to the current unix time in seconds since 1 januari 1970. This counter is used by several programs to create unique .pkt filenames, msgid numbers etc.

Environment.

In order to run mbtask you must set the global variable $MBSE_ROOT. This variable must point to the root directory of the bbs structure.

Security.

mbtask is installed setuid root. This is needed to initialize a raw socket for the ping function. After that is done the privilege drops to user mbse before the child process is created and the rest of the initialisation is done. The child process can never get root privileges because it is spawned by user mbse.

Communications.

Communication between the server and the clients is established by Unix datagram sockets. There can be only 1 server running. The server will accept connections from clients on your local machine only. The limit for the amount of clients that can connect to the server is set to 100.
The server creates a Unix datagram socket at startup and waits for connections. The name of this this socket is /opt/mbse/tmp/mbtask. When a client connects it creates a Unix datagram socket in /opt/mbse/tmp, the name is the name of the program, added with the pid of the program. So if mbcico is started with pid 2312 the socket will be /opt/mbse/tmp/mbcico2312.
All commands are 4 capital letters followed by a colon, a number indicating how much data fields will follow. If that number is higher than zero, the data fields are seperated with commas. The command is terminated with a ; character. Examples are:
GCLO:0;                 Zero datafields command.
DOPE:1,dbname;          One datafield command.
All commands will receive a reply as soon as possible. If a resource is temporary not available, a reply will follow too, telling this condition. Replies can also contain optional data. Examples:
100:0;                  Response 100, no data.
200:1,Syntax error;     One datafield.
The server has a 10 minute timeout for receiving data when a connection is established. The clients need to "ping" the server at regular intervals to prevent a disconnect. All official MBSE BBS programs do that. The pid send with most commands is the pid of the calling program. Since this number is unique, it is used to keep track of the connected clients.
The commands are divided in 26 catagories, most unused at this time.
Catagories:

Cat.    Description
----    -------------------------------------------
Axxx    Accounting, system monitor info etc.
Cxxx    Chatting
Gxxx    Global commands.
Sxxx    Status commands.



         Group A, Accounting.

Command: AINI:5,pid,tty,uid,prg,city;   Initialize connection, and who am I.
Reply:   100:0;                         Ok.
         200:1,Syntax Error;            Error.

Command: ADOI:2,pid,doing;              What am I doing right now.
Reply:   100:0;                         Ok.
         200:1,Syntax Error;            Error.

Command: ACLO:1,pid;                    Close my connection.
Reply:   107:0;                         Connection closed.
         200:1,Syntax Error;            Error, connection is still open.

Command: ALOG:5,fil,prg,pid,grade,txt;  Write a line of text in logfile with grade.
Reply:   100:0;                         Ok.
         201:1,errno;                   Error, number in errno.

Command: ATCP:1,pid;			Registrate this session as TCP/IP session.
Reply:   100:0;				Ok.
         200:1,Syntax Error;		Error.

Command: AUSR:3,pid,uid,city;           Set username and city
Reply:   100:0;                         Ok.
         200:1,Syntax Error;            Error.

Command: ADIS:2,pid,flag;               Set Do Not Disturb flag.
Reply:   100:0;                         Ok.
         200:1,Syntax Error;            Error.

Command: ATIM:1,time;                   Set new Client/Server timer in seconds.
Reply:   100:0;                         Ok.
         200:1,Syntax Error;            Error.

Command: ADEF:0;                        Set Client/Server timer to default (10 minutes).
Reply:   100:0;                         Ok.
         200:1,Syntax Error;            Error.

Command: ATTY:2,pid,tty;                Set new tty name.
Reply:   100:0;                         Ok.
         200:1,Syntax Error;            Error.


         Group C, Chatting (just some ideas).

Command: CIPM:1,pid;                    Is Personal Message present.
Reply:   100:2,fromname,message;        Yes, from .. with message text.
         100:0;                         No.

Command: CSPM:3,fromuser,touser,txt;    Send personal message to user.
Reply:   100:1,n;                       n: 0=Ok, 1=Do not disturb, 2=Buffer full, 3=Error.
         100:0;                         Impossible.

         The next commands are some ideas, they are not implemented.
	 Channel 0 will be for sysop chat only, other channels are
	 user channels.

        -CBPM:2,fromuser,txt;           Broadcast message to all users.
        -CJCH:2,pid,channel;            Join Channel
        -CCCH:2,pid,channel;            Close Channel
        -CAML:2,channel,text;           Add textline to channel
        -CIML:1,channel;                Is new textline present
        -CSSP:1,user,reason;            Send Sysop Page
        -CESP:1,user;                   Retract Sysop Page
        -CRSP:1,user;                   Reject user Page
        -CFCH:2,channel,user;           Force user in chatmode (for Sysop chat).
        -CKCH:2,channel,user;           Kill user chatmode (for Sysops and moderators).


         Group G, Global commands.

Command: GNOP:0;                        No OPerations.
Reply:   100:0;                         Ok.

Command: GPNG:1,data;                   Ping, echo data.
Reply:   100:1,data;                    Ping reply.

Command: GVER:0;                        Give server version.
Reply:   100:1,Version ....;            Version reply.

Command: GSTA:0;                        Get complete mbsed status record. (13 fields)
Reply:   100:20,start,laststart,daily,startups,clients,tot_clients,tot_peak,syntax_errs,
                com_errs,today_clients,today_peak,today_syntax,today_comerr,bbsopen,
                is_zmh,do_inet,processing,system_load,sequence;

Command: GMON:1,n;                      Get registration info line, 1=First, 0=Next line.
Reply:   100:7,pid,tty,user,program,city,isdoing,starttime;
         100:0;                         No more lines.

Command: GDST:0;                        Get filesystem status (see note below).
         100:n,data1, ..., data10;      Maximum 10 filesystems datalines.

Command: GSYS:0;                        Get bbs statistics.
         100:7,calls,pots_calls,isdn_calls,network_calls,local_calls,startdate,lastcaller;

Command: GLCC:0;                        Get Lastcallers count
         100,1,n;                       Return counter value.

Command: GLCR:1,recno;                  Get Lastcaller record
         100:9,user,location,level,tty,time,minsmcalls,speed,cations;
         201:1,16;                      Not available.


         Group S, Status commands.

Command: SBBS:0;                        Get BBS Status (open, zmh, shutdown).
Reply:   100:2,0,The system is open for use;
         100:2,1,The system is closed right now!;
         100:2,2,The system is closed for Zone Mail Hour!;

Command: SOPE:0;                        Open the BBS.
Reply:   100:0;                         Ok.

Command: SCLO:1,mesage;                 Close the BBS with reason.
Reply:   100:0;                         Ok.

Command: SFRE:0;                        Is the BBS Free.
Reply:   100:1,Running utilities: n  Active users: n;
         100:0;                         It's free.

Command: SSEQ:0;                        Get next unique sequence number.
Reply:   100:1,number;                  Next unique sequence number.

Command: SEST:1,semafore;               Get status of internal semafore.
Reply:   100:1,n;                       1 = set, 0 = not set.
         200:1,16;                      Semafore not known.

Command: SECR:1,semafore;               Set semafore
Reply:   100:0;                         Ok.
         200:1,16;                      Error.

Command: SERM:1,semafore;               Remove semafore
Reply:   100:0;                         Ok (also if there was no semafore).
         200:1,16;                      Semafore not known.
Note: in reply of GDST the reply is 100:n,size free mountpoint fstype,..... where n = 1 for 1 filesystem, and 10 for a total of 10 filesystems. There will never be a reply for more then 10 filesystems. The reported filesystems are retrieved from /etc/mtab which is the actual mountstatus. On FreeBSD and NetBSD a system call is used to get the information about the mounted filesystem. This is used by the mbmon program to get a "live" view of your filesystems.

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Semafore	Speed	Tasktype	Depends on	Job to run
mailout	Fast	mbfido	Max. 1 mbfido task	mbfido scan web -quiet
mailin	Fast	mbfido	Max. 1 mbfido task	mbfido tic toss web -quiet
newnews	Fast	mbfido	Max. 1 mbfido task	mbfido news web -quiet
mbindex	Fast	mbindex	No other tasks	mbindex -quiet and if exist: goldnode
msglink	Fast	mbfido	No other tasks	mbmsg link -quiet
reqindex	Fast	mbfile	No other tasks	mbfile index -quiet
scanout	Slow	call	Only 1 call task	mbcico -r1