1 SESSION LAYER PROTOCOL FOR CITADEL/UX
2 (c) 1995-1998 by Art Cancro et. al. All Rights Reserved
8 This is an attempt to document the session layer protocol used by the
9 Citadel/UX system, beginning with version 4.00, which is the first version
10 to implement a client/server paradigm. It is intended as a resource for
11 programmers who intend to develop their own Citadel clients, but it may have
15 IMPORTANT NOTE TO DEVELOPERS!
16 -----------------------------
18 Anyone who wants to add commands or other functionality to this protocol,
19 *please* get in touch so that these efforts can be coordinated. New
20 commands added by other developers can be added to this document, so we
21 don't end up with new server commands from multiple developers which have
22 the same name but perform different functions. If you don't coordinate new
23 developments ahead of time, please at least send in an e-mail documenting
24 what you did, so that your new commands can be added to this document.
26 The coordinator of the Citadel/UX project is Art Cancro <ajc@uncnsrd.mt-kisco.ny.us>.
29 CONNECTING TO A SERVER
30 ----------------------
32 The protocols used below the session layer are beyond the scope of this
33 document, but we will briefly cover a few of the currently used methods.
34 Keep in mind that the server program itself does not speak any protocols
35 lower than the session layer. Instead, it reads all input from stdin, and
36 writes all output to stdout. This implies that it is the responsibility of
37 other programs to provide a usable transport to the client programs.
39 One way to connect to a server is to use a set of pipes. This does of
40 course assume that the client and server are running on the same computer.
41 When the client starts up, the first thing that it does is create two pipes,
42 which it temporarily dup()'s to stdin and stdout. Then it proceeds to
43 fork() and exec() to a copy of the server program, which inherits the
44 pipes as its standard input and output - exactly the desired effect. The
45 client program can then re-connect its own stdin and stdout to where they're
46 supposed to be, and use the pipes to send and receive server messages.
48 Another way is to use TCP/IP. Under Unix-like systems this is easily
49 accomplished using the "inetd" superserver program, which can take programs
50 like the Citadel/UX server and offer connections to clients over a TCP or
51 UDP port. See the install documentation (or the inetd documentation from
52 your OS) for information on how to do this. Always use TCP ports for
53 Citadel/UX sessions. Since our session layer assumes a clean, reliable,
54 sequenced connection, the use of UDP would render the server unstable and
55 unusable. When operating in a TCP/IP environment, the port number officially
56 assigned to Citadel is 504.
59 GENERAL INFORMATION ABOUT THE SERVER
60 ------------------------------------
62 The server is connection-oriented and stateful: each client requires its own
63 connection to a server process, and when a command is sent, the client must
64 read the response, and then transfer data or change modes if necessary.
66 The session layer is very much like other Internet protocols such as SMTP
67 or NNTP. A client program sends one-line commands to the server, and the
68 server responds with a three-digit numeric result code followed by a message
69 describing what happened. This cycle continues until the end of the
72 Unlike protocols such as FTP, all data transfers occur in-band. This means
73 that the same connection that is used for exchange of client/server
74 messages, will also be used to transfer data back and forth. (FTP opens a
75 separate connection for data transfers.) We do this to allow the server to
76 function over transports which can only handle one session at a time (such
77 as a dialup connection).
83 The server will respond to all commands with a 3-digit result code, which
84 will be the first three characters on the line. The rest of the line may
85 contain a human-readable string explaining what happened. (Some client
86 software will display some of these strings to the user.)
88 The first digit is the most important. The following codes are defined for
89 this position: ERROR, OK, MORE_DATA, LISTING_FOLLOWS, and SEND_LISTING.
91 The second and third digits may provide a reason as to why a command
92 succeeded or failed. See ipcdef.h for the available codes.
94 ERROR means the command did not complete.
95 OK means the command executed successfully.
96 MORE_DATA means the command executed partially. Usually this means that
97 another command needs to be executed to complete the operation. For example,
98 sending the USER command to log in a user usually results in a MORE_DATA
99 result code, because the client needs to execute a PASS command to send the
100 password and complete the login.
101 LISTING_FOLLOWS means that after the server response, the server will
102 output a listing of some sort. The client *must* read the listing, whether
103 it wants to or not. The end of the listing is signified by the string
104 "000" on a line by itself.
105 SEND_LISTING is the opposite of LISTING_FOLLOWS. It means that the client
106 should begin sending a listing of some sort. The client *must* send something,
107 even if it is an empty listing. Again, the listing ends with "000" on a line
114 Zero or more parameters may be passed to a command. When more than one
115 parameter is passed to a command, they should be separated by the "|"
118 In this example, we're using the "SETU" command and passing three
119 parameters: 80, 24, and 260.
121 When the server spits out data that has parameters, if more than one
122 parameter is returned, they will be separated by the "|" symbol like
125 In this example, we just executed the "GETU" command, and it returned us
126 an OK result code (the '2' in the 200) and three parameters: 80, 24, and
133 This is a listing of all the commands that a Citadel/UX server can execute.
138 This command does nothing. It takes no arguments and always returns
139 OK. It is intended primarily for testing and development, but it might also
140 be used as a "keep alive" command to prevent the server from timing out, if
141 it's running over a transport that needs this type of thing.
144 ECHO (ECHO something)
146 This command also does nothing. It simply returns OK followed by whatever
152 Terminate the server connection. This command takes no arguments. It
153 returns OK and closes the connection immediately.
158 Log out the user without closing the server connection. It always returns
159 OK even if no user is logged in.
162 USER (send USER name)
164 The first step in logging in a user. This command takes one argument: the
165 name of the user to be logged in. If the user exists, a MORE_DATA return
166 code will be sent, which means the client should execute PASS as the next
167 command. If the user does not exist, ERROR is returned.
172 The second step in logging in a user. This command takes one argument: the
173 password for the user we are attempting to log in. If the password doesn't
174 match the correct password for the user we specified for the USER command,
175 or if a USER command has not been executed yet, ERROR is returned. If the
176 password is correct, OK is returned and the user is now logged in... and
177 most of the other server commands can now be executed. Along with OK, the
178 following parameters are returned:
180 0 - The user's name (in case the client wants the right upper/lower casing)
181 1 - The user's current access level
184 4 - Various flags (see citadel.h)
188 NEWU (create NEW User account)
190 This command creates a new user account and logs it in. The argument to
191 this command will be the name of the account. No case conversion is done
192 on the name. Note that the new account is installed with a default
193 configuration, and no password, so the client should immediately prompt the
194 user for a password and install it with the SETP command as soon as this
195 command completes. This command returns OK if the account was created and
196 logged in, or ERROR if another user already exists with this name. If OK,
197 it will also return the same parameters that PASS returns.
200 AUTO (AUTOmatic login **OBSLETE** )
202 Citadel/UX no longer supports this type of authentication. It was formerly
203 used to automatically authenticate a user based on the user ID under which
204 the server was running. Due to the new multithreaded architecture of the
205 server, this is no longer possible.
208 SETP (SET new Password)
210 This command sets a new password for the currently logged in user. The
211 argument to this command will be the new password. The command always
212 returns OK, unless the client is not logged in, in which case it will return
216 LKRN (List Known Rooms with New messages)
218 List known rooms with new messages. If the client is not logged in, ERROR
219 is returned. Otherwise, LISTING_FOLLOWS is returned, followed by the room
220 listing. Each line in the listing contains the full name of a room, followed
221 by the '|' symbol, and then a number that may contain the following bits:
224 #define QR_PERMANENT 1 /* Room does not purge */
225 #define QR_PRIVATE 4 /* Set for any type of private room */
226 #define QR_PASSWORDED 8 /* Set if there's a password too */
227 #define QR_GUESSNAME 16 /* Set if it's a guessname room */
228 #define QR_DIRECTORY 32 /* Directory room */
229 #define QR_UPLOAD 64 /* Allowed to upload */
230 #define QR_DOWNLOAD 128 /* Allowed to download */
231 #define QR_VISDIR 256 /* Visible directory */
232 #define QR_ANONONLY 512 /* Anonymous-Only room */
233 #define QR_ANON2 1024 /* Anonymous-Option room */
234 #define QR_NETWORK 2048 /* Shared network room */
235 #define QR_PREFONLY 4096 /* Preferred status needed to enter */
236 #define QR_READONLY 8192 /* Aide status required to post */
239 Other bits may be defined in the future. The listing terminates, as with
240 all listings, with "000" on a line by itself.
242 Version 4.01 and above only:
244 Starting with version 4.01 and above, floors are supported. The first
245 argument to LKRN should be the number of the floor to list rooms from. Only
246 rooms from this floor will be listed. If no arguments are passed to LKRN, or
247 if the floor number requested is (-1), rooms on all floors will be listed.
249 The third field displayed on each line is the number of the floor the room
250 is on. The LFLR command should be used to associate floor numbers with
255 LKRO (List Known Rooms with Old [no new] messages)
257 This follows the same usage and format as LKRN.
260 LZRM (List Zapped RooMs)
262 This follows the same usage and format as LKRN and LKRO.
265 LKRA (List All Known Rooms)
267 Same format. Lists all known rooms, with or without new messages.
270 LRMS (List all accessible RooMS)
272 Again, same format. This command lists all accessible rooms, known and
273 forgotten, with and without new messages. It does not, however, list
274 inaccessible private rooms.
277 GETU (GET User configuration)
279 This command retrieves the screen dimensions and user options for the
280 currently logged in account. ERROR will be returned if no user is logged
281 in, of course. Otherwise, OK will be returned, followed by three parameters.
282 The first parameter is the user's screen width, the second parameter is the
283 user's screen height, and the third parameter is a bag of bits with the
286 #define US_LASTOLD 16 /* Print last old message with new */
287 #define US_EXPERT 32 /* Experienced user */
288 #define US_UNLISTED 64 /* Unlisted userlog entry */
289 #define US_NOPROMPT 128 /* Don't prompt after each message */
290 #define US_DISAPPEAR 512 /* Use "disappearing msg prompts" */
291 #define US_PAGINATOR 2048 /* Pause after each screen of text */
293 There are other bits, too, but they can't be changed by the user (see below).
296 SETU (SET User configuration)
298 This command does the opposite of SETU: it takes the screen dimensions and
299 user options (which were probably obtained with a GETU command, and perhaps
300 modified by the user) and writes them to the user account. This command
301 should be passed three parameters: the screen width, the screen height, and
302 the option bits (see above).
304 Note that there exist bits here which are not listed in this document. Some
305 are flags that can only be set by Aides or the system administrator. SETU
306 will ignore attempts to toggle these bits. There also may be more user
307 settable bits added at a later date. To maintain later downward compatibility,
308 the following procedure is suggested:
310 1. Execute GETU to read the current flags
311 2. Toggle the bits that we know we can toggle
312 3. Execute SETU to write the flags
314 If we are passed a bit whose meaning we don't know, it's best to leave it
315 alone, and pass it right back to the server. That way we can use an old
316 client on a server that uses an unknown bit without accidentally clearing
317 it every time we set the user's configuration.
322 This command is used to goto a new room. When the user first logs in (login
323 is completed after execution of the PASS command) this command is
324 automatically and silently executed to take the user to the first room in the
325 system (usually called the Lobby).
327 This command can be passed one or two parameters. The first parameter is,
328 of course, the name of the room. Although it is not case sensitive, the
329 full name of the room must be used. Wildcard matching or unique string
330 matching of room names should be the responsibility of the client.
332 Note that the reserved room name "_BASEROOM_" can be passed to the server
333 to cause the goto command to take the user to the first room in the system,
334 traditionally known as the Lobby>. As long as a user is logged in, a
335 GOTO command to _BASEROOM_ is guaranteed to succeed. This is useful to
336 allow client software to return to the base room when it doesn't know
339 Citadel/UX server v4.01 and above, also has two additional reserved room
340 names. "_MAIL_" translates to the system's designated room for e-mail
341 messages, and "_BITBUCKET_" goes to whatever room has been chosen for messages
344 The second (and optional) parameter is a password, if one is required for
345 access to the room. This allows for all types of rooms to be accessed via
346 this command: for public rooms, invitation-only rooms to which the user
347 has access, and preferred users only rooms to which the user has access, the
348 room will appear in a room listing. For guess-name rooms, this command
349 will work transparently, adding the room to the user's known room list when
350 it completes. For passworded rooms, access will be denied if the password
351 is not supplied or is incorrect, or the command will complete successfully
352 if the password is correct.
354 The possible result codes are:
356 OK - The command completed successfully. User is now in the room.
357 (See the list of returned parameters below)
359 ERROR - The command did not complete successfully. Check the second and
360 third positions of the result code to find out what happened:
362 NOT_LOGGED_IN - Of course you can't go there. You didn't log in.
363 PASSWORD_REQUIRED - Either a password was not supplied, or the supplied
364 password was incorrect.
365 NO_SUCH_ROOM - The requested room does not exist.
367 The typical procedure for entering a passworded room would be:
369 1. Execute a GOTO command without supplying any password.
370 2. ERROR+PASSWORD_REQUIRED will be returned. The client now knows that
371 the room is passworded, and prompts the user for a password.
372 3. Execute a GOTO command, supplying both the room name and the password.
373 4. If OK is returned, the command is complete. If, however,
374 ERROR+PASSWORD_REQUIRED is still returned, tell the user that the supplied
375 password was incorrect. The user remains in the room he/she was previously
378 When the command succeeds, these parameters are returned:
379 0. The name of the room
380 1. Number of unread messages in this room
381 2. Total number of messages in this room
382 3. Info flag: set to nonzero if the user needs to read this room's info
383 file (see RINF command below)
384 4. Various flags associated with this room. (See LKRN cmd above)
385 5. The highest message number present in this room
386 6. The highest message number the user has read in this room
387 7. Boolean flag: 1 if this is a Mail> room, 0 otherwise.
388 8. Aide flag: 1 if the user is either the Room Aide for this room, *or* is
389 a regular Aide (this makes access checks easy).
391 ...and in server 4.01 and above:
392 9. The number of new Mail messages the user has (useful for alerting the
393 user to the arrival of new mail during a session)
395 ...and in server 4.03 and above:
396 10. The floor number this room resides on
399 MSGS (get pointers to MeSsaGeS in this room)
401 This command obtains a listing of all the messages in the current room
402 which the client may request. This command may be passed a single parameter:
403 either "all", "old", or "new" to request all messages, only old messages, or
404 new messages. Or it may be passed two parameters: "last" plus a number, in which
405 case that many message pointers will be returned, or "first" plus a number, for
406 the corresponding effect. If no parameters are specified, "all" is assumed.
408 In Citadel/UX 5.00 and above, the client may also specify "gt" plus a number, to
409 list all messages in the current room with a message number greater than the one
412 This command can return two possible results. An ERROR code may be returned
413 if no user is currently logged in or if something else went wrong. Otherwise,
414 LISTING_FOLLOWS will be returned, and the listing will consist of zero or
415 more message numbers, one per line. The listing ends, as always, with the
416 string "000" alone on a line by itself. The listed message numbers can be used
417 to request messages from the system.
420 MSG0 (read MeSsaGe, mode 0)
422 This is a command used to read the text of a message. "Mode 0" implies that
423 other MSG commands (MSG1, MSG2, etc.) will probably be added later on to read
424 messages in more robust formats. This command should be passed two arguments.
425 The first is the message number of the message being requested. In server
426 version 4.04 and above, the second argument may be set to either 0 to read the
427 entire message, or 1 to read the headers only. In server version 6.00 and
428 above, the third argument may be set to the desired section of the message (if
429 there are attachments).
431 The server should, of course, make sure that the client actually has access
432 to the message being requested before honoring this request. Citadel/UX does
433 so by checking the message number against the contents of the current room. If
434 it's not there, the request is denied.
436 If the request is denied, an ERROR code will be returned. Otherwise, the
437 LISTING_FOLLOWS code will be returned, followed by the contents of the message.
438 The following fields may be sent:
440 type= Formatting type. Currently, there are two defined types. Type 0 is
441 "traditional" Citadel formatting. This means that newlines should be treated
442 as spaces UNLESS the first character on the next line is a space. In other
443 words, only indented lines should generate a newline on the user's screen when
444 the message is being displayed. This allows a message to be formatted to the
445 reader's screen width. It also allows the use of proportional fonts.
446 Type 1 is a simple fixed-format message. The message should be displayed to
447 the user's screen as is, preferably in a fixed-width font that will fit 80
450 msgn= The message ID of this message on the system it originated on.
451 path= An e-mailable path back to the user who wrote the message.
453 time= The date and time of the message, in Unix format (the number of
454 seconds since midnight on January 1, 1970, GMT).
456 from= The name of the author of the message.
457 rcpt= If the message is a private e-mail, this is the recipient.
458 room= The name of the room the message originated in.
459 node= The short node name of the system this message originated on.
460 hnod= The long node name of the system this message originated on.
462 text Note that there is no "=" after the word "text". This string
463 signifies that the message text begins on the next line.
466 WHOK (WHO Knows room)
468 This command is available only to Aides. ERROR+HIGHER_ACCESS_REQUIRED will
469 be returned if the user is not an Aide. Otherwise, it returns
470 LISTING_FOLLOWS and then lists, one user per line, every user who has
471 access to the current room.
474 INFO (get server INFO)
476 This command will *always* return LISTING_FOLLOWS and then print out a
477 listing of zero or more strings. Client software should be written to expect
478 anywhere from a null listing to an infinite number of lines, to allow later
479 backward compatibility. The current implementation defines the following
480 parts of the listing:
482 Line 1 - Your unique session ID on the server
483 Line 2 - The node name of the server BBS
484 Line 3 - Human-readable node name of the server BBS
485 Line 4 - The fully-qualified domain name (FQDN) of the server
486 Line 5 - The name of the server software, i.e. "Citadel/UX 4.00"
487 Line 6 - (The revision level of the server code) * 100
488 Line 7 - The geographical location of the BBS (for USA: city and state)
489 Line 8 - The name of the system administrator
490 Line 9 - A number identifying the server type (see below)
491 Line 10 - The text of the system's paginator prompt
493 (version 4.01 and above only)
494 Line 11 - Floor Flag. 1 if the system supports floors, 0 otherwise.
496 *** NOTE! *** The "server type" code is intended to promote global
497 compatibility in a scenario in which developers have added proprietary
498 features to their servers or clients. We are attempting to avoid a future
499 situation in which users need to keep different client software around for
500 each BBS they use. *Please*, if you are a developer and plan to add
501 proprietary features:
503 -> Your client programs should still be able to utilize servers other than
505 -> Clients other than your own should still be able to utilize your server,
506 even if your proprietary extensions aren't supported.
507 -> Please contact Art Cancro <ajc@uncnsrd.mt-kisco.ny.us> and obtain a unique
508 server type code, which can be assigned to your server program.
509 -> If you document what you did in detail, perhaps it can be added to a
510 future release of the Citadel/UX program, so everyone can enjoy it. Better
511 yet, just work with the Citadel development team on the main source tree.
513 If everyone follows this scheme, we can avoid a chaotic situation with lots
514 of confusion about which client program works with which server, etc. Client
515 software can simply check the server type (and perhaps the revision level)
516 to determine ahead of time what commands may be utilized. The server type
517 codes currently defined are:
520 ---- ---------------------------------------
521 0 Art Cancro <ajc@uncnsrd.mt-kisco.ny.us>
522 1 Brian Ledbetter <brian@amaranth.com>
523 2 Matthew Scott <gldnspud@telcomplus.com>
524 3 Jesse Vincent <jrvincent@wesleyan.edu>
525 4 Brian Costello <btx@calyx.net>
526 5 Robert Abatecola <robert@tsgus.com>
530 RDIR (Read room DIRectory)
532 Use this command to read the directory of a directory room. ERROR+NOT_HERE
533 will be returned if the room has no directory, or some other error; ERROR +
534 HIGHER_ACCESS_REQUIRED will be returned if the room's directory is not
535 visible and the user does not have Aide or Room Aide privileges; otherwise
536 LISTING_FOLLOWS will be returned, followed by the room's directory. Each
537 line of the directory listing will contain three fields: a filename, the
538 length of the file, and a description.
540 The server message contained on the same line with LISTING_FOLLOWS will
541 contain the name of the system and the name of the directory, such as:
542 uncnsrd.mt-kisco.ny.us|/usr/bbs/files/my_room_directory
545 SLRP (Set Last-message-Read Pointer)
547 This command is used to mark messages as having been read. Its sole parameter
548 is the number of the last message that has been read. This allows the pointer
549 to be set at any arbitrary point in the room. Optionally, the parameter
550 "highest" may be used instead of a message number, to set the pointer to the
551 number of the highest message in the room, effectively marking all messages
552 in the room as having been read (ala the Citadel <G>oto command).
554 The command will return OK if the pointer was set, or ERROR if something
555 went wrong. If OK is returned, it will be followed by a single argument
556 containing the message number the last-read-pointer was set to.
559 INVT (INViTe a user to a room)
561 This command may only be executed by Aides, or by the room aide for the
562 current room. It is used primarily to add users to invitation-only rooms,
563 but it may also be used in other types of private rooms as well. Its sole
564 parameter is the name of the user to invite.
566 The command will return OK if the operation succeeded, or ERROR if it did
567 not. ERROR+HIGHER_ACCESS_REQUIRED may also be returned if the operation
568 would have been possible if the user had higher access, and ERROR+NOT_HERE
569 may be returned if the room is not a private room.
572 KICK (KICK a user out of a room)
574 This is the opposite of INVT: it is used to kick a user out of a private
575 room. It can also be used to kick a user out of a public room, but the
576 effect will only be the same as if the user <Z>apped the room - a non-stupid
577 user can simply un-zap the room to get back in.
580 GETR (GET Room attributes)
582 This command is used for editing the various attributes associated with a
583 room. A typical "edit room" command would work like this:
584 1. Use the GETR command to get the current attributes
585 2. Change some of them around
586 3. Use SETR (see below) to save the changes
587 4. Possibly also change the room aide using the GETA and SETA commands
589 GETR takes no arguments. It will only return OK if the SETR command will
590 also return OK. This allows client software to tell the user that he/she
591 can't edit the room *before* going through the trouble of actually doing the
592 editing. Possible return codes are:
594 ERROR+NOT_LOGGED_IN - No user is logged in.
595 ERROR+HIGHER_ACCESS_REQUIRED - Not enough access. Typically, only aides
596 and the room aide associated with the current room, can access this command.
597 ERROR+NOT_HERE - Lobby>, Mail>, and Aide> cannot be edited.
598 OK - Command succeeded. Parameters are returned.
600 If OK is returned, the following parameters will be returned as well:
602 0. The name of the room
603 1. The room's password (if it's a passworded room)
604 2. The name of the room's directory (if it's a directory room)
605 3. Various flags (bits) associated with the room (see LKRN cmd above)
607 (And on server version 4.01 and above ... )
608 4. The floor number on which the room resides
611 SETR (SET Room attributes)
613 This command sets various attributes associated with the current room. It
614 should be passed the following arguments:
616 0. The name of the room
617 1. The room's password (if it's a passworded room)
618 2. The name of the room's directory (if it's a directory room)
619 3. Various flags (bits) associated with the room (see LKRN cmd above)
620 4. "Bump" flag (see below)
622 (And on server version 4.01 and above, the client may also send ... )
623 5. The floor number on which the room should reside
625 *Important: You should always use GETR to retrieve the current attributes of
626 the room, then change what you want to change, and then use SETR to write it
627 all back. This is particularly important with respect to the flags: if a
628 particular bit is set, and you don't know what it means, LEAVE IT ALONE and
629 only toggle the bits you want to toggle. This will allow for upward
632 If the room is a private room, you have the option of causing all users who
633 currently have access, to forget the room. If you want to do this, set the
634 "bump" flag to 1, otherwise set it to 0.
639 This command is used to get the name of the Room Aide for the current room.
640 It will return ERROR+NOT_LOGGED_IN if no user is logged in, ERROR if there
641 is no current room, or OK if the command succeeded. Along with OK there will
642 be returned one parameter: the name of the Room Aide.
647 The opposite of GETA, used to set the Room Aide for the current room. One
648 parameter should be passed, which is the name of the user who is to be the
649 new Room Aide. Under Citadel/UX, this command may only be executed by Aides
650 and by the *current* Room Aide for the room. Return codes possible are:
651 ERROR+NOT_LOGGED_IN (Not logged in.)
652 ERROR+HIGHER_ACCESS_REQUIRED (Higher access required.)
653 ERROR+NOT_HERE (No current room, or room cannot be edited.
654 Under Citadel/UX, the Lobby> Mail> and Aide> rooms are non-editable.)
655 OK (Command succeeded.)
658 ENT0 (ENTer message, mode 0)
660 This command is used to enter messages into the system. It accepts four
663 0 - Post flag. This should be set to 1 to post a message. If it is
664 set to 0, the server only returns OK or ERROR (plus any flags describing
665 the error) without reading in a message. Client software should, in fact,
666 perform this operation at the beginning of an "enter message" command
667 *before* starting up its editor, so the user does not end up typing a message
668 in vain that will not be permitted to be saved. If it is set to 2, the
669 server will accept an "apparent" post name if the user is privileged enough.
670 This post name is arg 4.
671 1 - Recipient. This argument is utilized only for private mail messages.
672 It is ignored for public messages. It contains, of course, the name of the
673 recipient of the message.
674 2 - Anonymous flag. This argument is ignored unless the room allows
675 anonymous messages. In such rooms, this flag may be set to 1 to flag a
676 message as anonymous, otherwise 0 for a normal message.
677 3 - Format type. Any valid Citadel/UX format type may be used (this will
678 typically be 0; see the MSG0 command above).
679 4 - Post name. When postflag is 2, this is the name you are posting as.
680 This is an Aide only command.
681 5 - Boundary string to be used when there are MIME attachments following
682 the normal message text.
684 Possible result codes:
685 OK - The request is valid. (Client did not set the "post" flag, so the
686 server will not read in message text.) If the message is an e-mail with
687 a recipient, the text that follows the OK code will contain the exact name
688 to which mail is being sent. The client can display this to the user. The
689 implication here is that the name that the server returns will contain the
690 correct upper and lower case characters. In addition, if the recipient is
691 having his/her mail forwarded, the forwarding address will be returned.
692 SEND_LISTING - The request is valid. The client should now transmit
693 the text of the message (ending with a 000 on a line by itself, as usual).
694 ERROR - Miscellaneous error. (Explanation probably follows.)
695 ERROR + NOT_LOGGED_IN - Not logged in.
696 ERROR + HIGHER_ACCESS_REQUIRED - Higher access is required. An
697 explanation follows, worded in a form that can be displayed to the user.
698 ERROR + NO_SUCH_USER - The specified recipient does not exist.
701 RINF (read Room INFormation file)
703 Each room has associated with it a text file containing a description of
704 the room, perhaps containing its intended purpose or other important
705 information. The info file for the Lobby> (the system's base room) is
706 often used as a repository for system bulletins and the like.
708 This command, which accepts no arguments, is simply used to read the info
709 file for the current room. It will return LISTING_FOLLOWS followed by
710 the text of the message (always in format type 0) if the request can be
711 honored, or ERROR if no info file exists for the current room (which is
712 often the case). Other error description codes may accompany this result.
714 When should this command be used? This is, of course, up to the discretion
715 of client software authors, but in Citadel it is executed in two situations:
716 the first time the user ever enters a room; and whenever the contents of the
717 file change. The latter can be determined from the result of a GOTO command,
718 which will tell the client whether the file needs to be read (see GOTO above).
721 DELE (DELEte a message)
723 Delete a message from the current room. The one argument that should be
724 passed to this command is the message number of the message to be deleted.
725 The return value will be OK if the message was deleted, or an ERROR code.
728 MOVE (MOVE a message to a different room)
730 Move a message to a different room. The two arguments that should be passed
731 to this command are the message number of the message to be deleted, and the
732 name of the target room. If the operation succeeds, the message will be
733 deleted from the current room and moved to the target room. An ERROR code
734 usually means that either the user does not have permission to perform this
735 operation, or that the target room does not exist.
738 KILL (KILL current room)
740 This command deletes the current room. It accepts a single argument, which
741 should be nonzero to actually delete the room, or zero to merely check
742 whether the room can be deleted.
744 Once the room is deleted, the current room is undefined. It is suggested
745 that client software immediately GOTO another room (usually _BASEROOM_)
746 after this command completes.
748 Possible return codes:
750 OK - room has been deleted (or, if checking only, request is valid).
751 ERROR+NOT_LOGGED_IN - no user is logged in.
752 ERROR+HIGHER_ACCESS_REQUIRED - not enough access to delete rooms.
753 ERROR+NOT_HERE - this room can not be deleted.
756 CRE8 (CRE[ate] a new room)
758 This command is used to create a new room. Like some of the other
759 commands, it provides a mechanism to first check to see if a room can be
760 created before actually executing the command. CRE8 accepts the following
763 0 - Create flag. Set this to 1 to actually create the room. If it is
764 set to 0, the server merely checks that there is a free slot in which to
765 create a new room, and that the user has enough access to create a room. It
766 returns OK if the client should go ahead and prompt the user for more info,
767 or ERROR or ERROR+HIGHER_ACCESS_REQUIRED if the command will not succeed.
768 1 - Name for new room.
769 2 - Access type for new room:
771 1 - Private; can be entered by guessing the room's name
772 2 - Private; can be entered by knowing the name *and* password
773 3 - Private; invitation only (sometimes called "exclusive")
774 3 - Password for new room (if it is a type 2 room)
775 4 - Floor number on which the room should reside (optional, and in server
776 version 4.01 and above only)
778 If the create flag is set to 1, the room is created (unless something
779 went wrong and an ERROR return is sent), and the server returns OK, but
780 the session is **not** automatically sent to that room. The client still
781 must perform a GOTO command to go to the new room.
784 FORG (FORGet the current room)
786 This command is used to forget (zap) the current room. For those not
787 familiar with Citadel, this terminology refers to removing the room from
788 a user's own known rooms list, *not* removing the room itself. After a
789 room is forgotten, it no longer shows up in the user's known room list,
790 but it will exist in the user's forgotten room list, and will return to the
791 known room list if the user goes to the room (in Citadel, this is
792 accomplished by explicitly typing the room's name in a <.G>oto command).
794 The command takes no arguments. If the command cannot execute for any
795 reason, ERROR will be returned. ERROR+NOT_LOGGED_IN or ERROR+NOT_HERE may
796 be returned as they apply.
798 If the command succeeds, OK will be returned. At this point, the current
799 room is **undefined**, and the client software is responsible for taking
800 the user to another room before executing any other room commands (usually
801 this will be _BASEROOM_ since it is always there).
804 MESG (read system MESsaGe)
806 This command is used to display system messages and/or help files. The
807 single argument it accepts is the name of the file to display. IT IS CASE
808 SENSITIVE. Citadel/UX looks for these files first in the "messages"
809 subdirectory and then in the "help" subdirectory.
811 If the file is found, LISTING_FOLLOWS is returned, followed by a pathname
812 to the file being displayed. Then the message is printed, in format type 0
813 (see MSG0 command for more information on this). If the file is not found,
816 There are some "well known" names of system messages which client software
817 may expect most servers to carry:
819 hello - Welcome message, to be displayed before the user logs in.
820 changepw - To be displayed whenever the user is prompted for a new
821 password. Warns about picking guessable passwords and such.
822 register - Should be displayed prior to the user entering registration.
823 Warnings about not getting access if not registered, etc.
824 help - Main system help file.
825 goodbye - System logoff banner; display when user logs off.
826 roomaccess - Information about how public rooms and different types of
827 private rooms function with regards to access.
828 unlisted - Tells users not to choose to be unlisted unless they're
829 really paranoid, and warns that aides can still see
830 unlisted userlog entries.
832 Citadel/UX provides these for the Citadel/UX Unix text client. They are
833 probably not very useful for other clients:
835 mainmenu - Main menu (when in idiot mode).
840 saveopt - Options to save a message, abort, etc.
841 entermsg - Displayed just before a message is entered, when in
845 GNUR (Get Next Unvalidated User)
847 This command shows the name of a user that needs to be validated. If there
848 are no unvalidated users, OK is returned. Otherwise, MORE_DATA is returned
849 along with the name of the first unvalidated user the server finds. All of
850 the usual ERROR codes may be returned as well (for example, if the user is
851 not an Aide and cannot validate users).
853 A typical "Validate New Users" command would keep executing this command,
854 and then validating each user it returns, until it returns OK when all new
855 users have been validated.
858 GREG (Get REGistration for user)
860 This command retrieves the registration info for a user, whose name is the
861 command's sole argument. All the usual error messages can be returned. If
862 the command succeeds, LISTING_FOLLOWS is returned, followed by the user's name
863 (retrieved from the userlog, with the right upper and lower case etc.) The
864 contents of the listing contains one field per line, followed by the usual
865 000 on the last line.
867 The following lines are defined. Others WILL be added in the futre, so all
868 software should be written to read the lines it knows about and then ignore
874 Line 4: Street address or PO Box
875 Line 5: City/town/village/etc.
876 Line 6: State/province/etc.
878 Line 8: Telephone number
880 Line 10: Internet e-mail address
882 Users without Aide privileges may retrieve their own registration using
883 this command. This can be accomplished either by passing the user's own
884 name as the argument, or the string "_SELF_". The command will always
885 succeed when used in this manner, unless no user is logged in.
890 This command is used to validate users. Obviously, it can only be executed
891 by users with Aide level access. It should be passed two parameters: the
892 name of the user to validate, and the desired access level
894 If the command succeeds, OK is returned. The user's access level is changed
895 and the "need validation" bit is cleared. If the command fails for any
896 reason, ERROR, ERROR+NO_SUCH_USER, or ERROR+HIGHER_ACCESS_REQUIRED will be
900 EINF (Enter INFo file for room)
902 Transmit the info file for the current room with this command. EINF uses
903 a boolean flag (1 or 0 as the first and only argument to the command) to
904 determine whether the client actually wishes to transmit a new info file, or
905 is merely checking to see if it has permission to do so.
907 If the command cannot succeed, it returns ERROR.
908 If the client is only checking for permission, and permission will be
909 granted, OK is returned.
910 If the client wishes to transmit the new info file, SEND_LISTING is
911 returned, and the client should transmit the text of the info file, ended
912 by the usual 000 on a line by itself.
917 This is a simple user listing. It always succeeds, returning
918 LISTING_FOLLOWS followed by zero or more user records, 000 terminated. The
919 fields on each line are as follows:
924 4. Date/time of last login (Unix format)
927 7. Password (listed only if the user requesting the list is an Aide)
929 Unlisted entries will also be listed to Aides logged into the server, but
930 not to ordinary users.
933 REGI (send REGIstration)
935 Clients will use this command to transmit a user's registration info. If
936 no user is logged in, ERROR+NOT_LOGGED_IN is returned. Otherwise,
937 SEND_LISTING is returned, and the server will expect the following information
938 (terminated by 000 on a line by itself):
941 Line 2: Street address or PO Box
942 Line 3: City/town/village/etc.
943 Line 4: State/province/etc.
945 Line 6: Telephone number
946 Line 7: e-mail address
949 CHEK (CHEcK various things)
951 When logging in, there are various things that need to be checked. This
952 command will return ERROR+NOT_LOGGED_IN if no user is logged in. Otherwise
953 it returns OK and the following parameters:
955 0: Number of new private messages in Mail>
956 1: Nonzero if the user needs to register
957 2: (Relevant to Aides only) Nonzero if new users require validation
962 This command deletes a file from the room's directory, if there is one. The
963 name of the file to delete is the only parameter to be supplied. Wildcards
964 are not acceptable, and any slashes in the filename will be converted to
965 underscores, to prevent unauthorized access to neighboring directories. The
966 possible return codes are:
968 OK - Command succeeded. The file was deleted.
969 ERROR+NOT_LOGGED_IN - Not logged in.
970 ERROR+HIGHER_ACCESS_REQUIRED - Not an Aide or Room Aide.
971 ERROR+NOT_HERE - There is no directory in this room.
972 ERROR+FILE_NOT_FOUND - Requested file was not found.
977 This command is similar to DELF, except that it moves a file (and its
978 associated file description) to another room. It should be passed two
979 parameters: the name of the file to move, and the name of the room to move
980 the file to. All of the same return codes as DELF may be returned, and also
981 one additional one: ERROR+NO_SUCH_ROOM, which means that the target room
982 does not exist. ERROR+NOT_HERE could also mean that the target room does
983 not have a directory.
986 NETF (NETwork send a File)
988 This command is similar to MOVF, except that it attempts to send a file over
989 the network to another system. It should be passed two parameters: the name
990 of the file to send, and the node name of the system to send it to. All of
991 the same return codes as MOVF may be returned, except for ERROR+NO_SUCH_ROOM.
992 Instead, ERROR+NO_SUCH_SYSTEM may be returned if the name of the target
995 The name of the originating room will be sent along with the file. Most
996 implementations will look for a room with the same name at the receiving end
997 and attempt to place the file there, otherwise it goes into a bit bucket room
998 for miscellaneous files. This is, however, beyond the scope of this document;
999 see elsewhere for more details.
1002 RWHO (Read WHO's online)
1004 Displays a list of all users connected to the server. No error codes are
1005 ever returned. LISTING_FOLLOWS will be returned, followed by zero or more
1006 lines containing the following three fields:
1008 0 - Session ID. Citadel/UX fills this with the pid of a server program.
1010 2 - The name of the room the user is currently in. This field might not
1011 be displayed (for example, if the user is in a private room) or it might
1012 contain other information (such as the name of a file the user is
1014 3 - (server v4.03 and above) The name of the host the client is connecting
1015 from, or "localhost" if the client is local.
1016 4 - (server v4.04 and above) Description of the client software being used
1017 5 - The last time, locally to the server, that a command was received from
1018 this client (Note: NOOP's don't count)
1019 6 - The last command received from a client. (NOOP's don't count)
1020 7 - Session flags. These are: + (spoofed address), - (STEALTH mode), *
1021 (posting) and . (idle). (Citserver 5.02 and above)
1023 The listing is terminated, as always, with the string "000" on a line by
1027 OPEN (OPEN a file for download)
1029 This command is used to open a file for downloading. Only one download
1030 file may be open at a time. The only argument to this command is the name
1031 of the file to be opened. The user should already be in the room where the
1032 file resides. Possible return codes are:
1035 ERROR+NOT_HERE (no directory in this room)
1036 ERROR+FILE_NOT_FOUND (could not open the file)
1040 If the file is successfully opened, OK will be returned, along with the
1041 size (in bytes) of the file, and (in version 5.00 and above) the time of last
1045 CLOS (CLOSe the download file)
1047 This command is used to close the download file. It returns OK if the
1048 file was successfully closed, or ERROR if there wasn't any file open in the
1052 READ (READ from the download file)
1054 Two arguments are passed to this command. The first is the starting position
1055 in the download file, and the second is the total number of bytes to be
1056 read. If the operation can be performed, BINARY_FOLLOWS will be returned,
1057 along with the number of bytes to follow. Then, immediately following the
1058 newline, will be that many bytes of binary data. The client *must* read
1059 exactly that number of bytes, otherwise the client and server will get out
1062 If the operation cannot be performed, any of the usual error codes will be
1066 UOPN (OPeN a file for Uploading)
1068 This command is similar to OPEN, except that this one is used when the
1069 client wishes to upload a file to the server. The first argument is the name
1070 of the file to create, and the second argument is a one-line comment
1071 describing the contents of the file. Only one upload file may be open at a
1072 time. Possible return codes are:
1075 ERROR+NOT_HERE (no directory in this room)
1076 ERROR+FILE_NOT_FOUND (a name must be specified)
1077 ERROR (miscellaneous errors)
1078 ERROR+ALREADY_EXISTS (a file with the same name already exists)
1081 If OK is returned, the command has succeeded and writes may be performed.
1084 UCLS (CLoSe the Upload file)
1086 Close the file opened with UOPN. An argument of "1" should be passed to
1087 this command to close and save the file; otherwise, the transfer will be
1088 considered aborted and the file will be deleted. This command returns OK
1089 if the operation succeeded or ERROR if it did not.
1092 WRIT (WRITe to the upload file)
1094 If an upload file is open, this command may be used to write to it. The
1095 argument passed to this command is the number of bytes the client wishes to
1096 transmit. An ERROR code will be returned if the operation cannot be
1099 If the operation can be performed, SEND_BINARY will be returned, followed
1100 by the number of bytes the server is expecting. The client must then transmit
1101 exactly that number of bytes. Note that in the current implementation, the
1102 number of bytes the server is expecting will always be the number of bytes
1103 the client requested to transmit, but the client software should never assume
1104 that this will always happen, in case changes are made later.
1107 QUSR (Query for a USeR)
1109 This command is used to check to see if a particular user exists. The only
1110 argument to this command is the name of the user being searched for. If
1111 the user exists, OK is returned, along with the name of the user in the userlog
1112 (so the client software can learn the correct upper/lower casing of the name
1113 if necessary). If the user does not exist, ERROR+NO_SUCH_USER is returned.
1114 No login or current room is required to utilize this command.
1117 OIMG (Open an IMaGe file)
1119 Open an image (graphics) file for downloading. Once opened, the file can be
1120 read as if it were a download file. This implies that an image and a download
1121 cannot be opened at the same time. OIMG returns the same result codes as OPEN.
1123 All images will be in GIF (Graphics Interchange Format). In the case of
1124 Citadel/UX, the server will convert the supplied filename to all lower case,
1125 append the characters ".gif" to the filename, and look for it in the "images"
1126 subdirectory. As with the MESG command, there are several "well known"
1127 images which are likely to exist on most servers:
1129 hello - "Welcome" graphics to be displayed alongside MESG "hello"
1130 goodbye - Logoff banner graphics to be displayed alongside MESG "goodbye"
1131 background - Background image (usually tiled) for graphical clients
1133 The following "special" image names are defined in Citadel/UX server version
1136 _userpic_ - Picture of a user (send the username as the second argument)
1137 _floorpic_ - A graphical floor label (send the floor number as the second
1138 argument). Clients which request a floor picture will display
1139 the picture *instead* of the floor name.
1140 _roompic_ - A graphic associated with the *current* room. Clients which
1141 request a room picture will display the picture in *addition*
1142 to the room name (i.e. it's used for a room banner, as
1143 opposed to the floor picture's use in a floor listing).
1147 ---------------------------------------------------------------------------
1148 The following commands are available only in Citadel/UX server version 4.01
1150 ---------------------------------------------------------------------------
1152 NETP (authenticate as network session with system NET Password)
1154 This command is used by client software to identify itself as a transport
1155 session for IGnet/Open BBS to BBS networking. It should be called with
1156 two arguments: the node name of the calling system, and the system net
1157 password for the server. If the authentication succeeds, NETP will return
1158 OK, otherwise, it returns ERROR.
1161 NUOP (Network Upload OPen file)
1163 Open a network spool file for uploading. The client must have already
1164 identified itself as a network session using the NETP command. If the command
1165 returns OK, the client may begin transmitting IGnet/Open spool data using
1166 a series of WRIT commands. When a UCLS command is issued, the spooled data
1167 is entered into the BBS if the argument to UCLS is 1 or discarded if the
1168 argument to UCLS is 0. If the client has not authenticated itself with a
1169 NETP command, ERROR+HIGHER_ACCESS_REQUIRED will be returned.
1172 NDOP (Network Download OPen file)
1174 Open a network spool file for downloading. The client must have already
1175 identified itself as a network session using the NETP command. If the command
1176 returns OK, the client may begin receiving IGnet/Open spool data using
1177 a series of READ commands. When a CLOS command is issued, the spooled data
1178 is deleted from the server and may not be read again. If the client has not
1179 authenticated itself with a NETP command, ERROR+HIGHER_ACCESS_REQUIRED will
1183 LFLR (List all known FLooRs)
1185 On systems supporting floors, this command lists all known floors. The
1186 command accepts no parameters. It will return ERROR+NOT_LOGGED_IN if no
1187 user is logged in. Otherwise it returns LISTING_FOLLOWS and a list of
1188 the available floors, each line consisting of three fields:
1190 1. The floor number associated with the floor
1191 2. The name of the floor
1192 3. Reference count (number of rooms on this floor)
1195 CFLR (Create a new FLooR)
1197 This command is used to create a new floor. It should be passed two
1198 arguments: the name of the new floor to be created, and a 1 or 0 depending
1199 on whether the client is actually creating a floor or merely checking to
1200 see if it has permission to create the floor. The user must be logged in
1201 and have Aide privileges to create a floor.
1203 If the command succeeds, it will return OK followed by the floor number
1204 associated with the new floor. Otherwise, it will return ERROR (plus perhaps
1205 HIGHER_ACCESS_REQUIRED, ALREADY_EXISTS, or INVALID_FLOOR_OPERATION)
1206 followed by a description of why the command failed.
1211 This command is used to delete a floor. It should be passed two
1212 argument: the *number* of the floor to be deleted, and a 1 or 0 depending
1213 on whether the client is actually deleting the floor or merely checking to
1214 see if it has permission to delete the floor. The user must be logged in
1215 and have Aide privileges to delete a floor.
1217 Floors that contain rooms may not be deleted. If there are rooms on a floor,
1218 they must be either deleted or moved to different floors first. This implies
1219 that the Main Floor (floor 0) can never be deleted, since Lobby>, Mail>, and
1220 Aide> all reside on the Main Floor and cannot be deleted.
1222 If the command succeeds, it will return OK. Otherwise it will return
1223 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1224 followed by a description of why the command failed.
1229 Edit the parameters of a floor. The client may pass one or more parameters
1232 1. The number of the floor to be edited
1233 2. The desired new name
1235 More parameters may be added in the future. Any parameters not passed to
1236 the server will remain unchanged. A minimal command would be EFLR and a
1237 floor number -- which would do nothing. EFLR plus the floor number plus a
1238 floor name would change the floor's name.
1240 If the command succeeds, it will return OK. Otherwise it will return
1241 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1243 ---------------------------------------------------------------------------
1244 The following commands are available only in Citadel/UX server version 4.02
1246 ---------------------------------------------------------------------------
1248 IDEN (IDENtify the client software)
1250 The client software has the option to identify itself to the server.
1251 Currently, the server does nothing with this information except to write
1252 it to the syslog to satisfy the system administrator's curiosity. Other
1253 uses might become apparent in the future.
1255 The IDEN command should contain five fields: a developer ID number (same as
1256 the server developer ID numbers in the INFO command -- please obtain one if
1257 you are a new developer), a client ID number (which does not have to be
1258 globally unique - only unique within the domain of the developer number),
1259 a version number, a free-form text string describing the client, and the name
1260 of the host the user is located at.
1262 It is up to the server to determine whether to accept the host name or to
1263 use the host name it has detected itself. Generally, if the client is
1264 running on a trusted host (either localhost or a well-known publically
1265 accessible client) it should use the host name transmitted by IDEN,
1266 otherwise it should use the host name it has detected itself.
1268 IDEN always returns OK, but since that's the only way it ever returns
1269 there's no point in checking the result code.
1271 ---------------------------------------------------------------------------
1272 The following commands are available only in Citadel/UX server version 4.03
1274 ---------------------------------------------------------------------------
1276 IPGM (identify as an Internal ProGraM)
1278 IPGM is a low-level command that should not be used by normal user clients.
1279 It is used for various utilities to communicate with the server on the same
1280 host. For example, the networker (netproc.c) logs onto the server as an
1281 internal program in order to fetch and store messages. Since user clients
1282 do not utilize this command (or any of its companion commands), developers
1283 writing Citadel-compatible servers need not implement it.
1285 The sole argument to IPGM is the system's internal program password. This
1286 password is generated by the setup program and stored in the config file.
1287 Since internal programs have access to the config file, they know the correct
1290 IPGM returns OK for a correct authentication or ERROR otherwise.
1293 CHAT (enter CHAT mode)
1295 This command functions differently from every other command in the system. It
1296 is used to implement multi-user chat. For this to function, a new transfer
1297 mode, called START_CHAT_MODE, is implemented. If a client does not support
1298 chat mode, it should never send a CHAT command!
1300 In chat mode, messages may arrive asynchronously from the server at any
1301 time. The client may send messages at any time. This allows the arrival of
1302 messages without the client having to poll for them. Arriving messages will
1303 be of the form "user|message", where the "user" portion is, of course, the
1304 name of the user sending the message, and "message" is the message text.
1306 Chat mode ends when the server says it ends. The server will signal the end
1307 of chat mode by transmitting "000" on a line by itself. When the client reads
1308 this line, it must immediately exit from chat mode without sending any
1309 further traffic to the server. The next transmission sent to the server
1310 will be a regular server command.
1312 The Citadel/UX server understands the following commands:
1313 /quit - Exit from chat mode (causes the server to do an 000 end)
1314 /who - List users currently in chat
1315 /whobbs - List users currently in chat and on the bbs
1316 /me - Do an irc-style action.
1317 /join - Join a new "room" in which all messages are only heard by
1318 people in that room.
1319 /msg - /msg <user> <msg> will send the msg to <user> only.
1320 /help - Print help information
1321 NOOP - Do nothing (silently)
1323 Any other non-empty string is treated as message text and will be broadcast
1324 to other users currently in chat.
1327 SEXP (Send EXPress messages)
1329 This is one of two commands which implement "express messages" (also known
1330 as "paging"). An express message is a near-real-time message sent from one
1331 logged in user to another. When an express message is sent, it will be
1332 displayed the next time the target user executes a PEXP command.
1334 The SEXP command accepts two arguments: the name of the user to send the
1335 message to, and the text of the message. If the message is successfully
1336 transmitted, OK is returned. If the target user is not logged in or if
1337 anything else goes wrong, ERROR is returned.
1339 In Citadel/UX 5.00 and above, the reserved name "broadcast" may be used
1340 instead of a user name, to broadcast an express message to all users
1341 currently connected to the server.
1343 Do be aware that if an express message is transmitted to a user who is logged
1344 in using a client that does not check for express messages, the message will
1348 PEXP (Print EXPress messages)
1350 This command, called without any arguments, simply dumps out the contents
1351 of any waiting express messages. It returns ERROR if there is a problem,
1352 otherwise it returns LISTING_FOLLOWS followed by all messages.
1354 So how does the client know there are express messages waiting? It could
1355 execute a random PEXP every now and then. Or, it can check the byte in
1356 server return code messages, between the return code and the parameters. In
1357 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1358 an "*" in this position to signify the presence of waiting express messages.
1360 ---------------------------------------------------------------------------
1361 The following commands are available only in Citadel/UX server version 4.10
1363 ---------------------------------------------------------------------------
1365 EBIO (Enter BIOgraphy)
1367 Transmit to the server a free-form text file containing a little bit of
1368 information about the user for other users to browse. This is typically
1369 referred to as a 'bio' online. EBIO returns SEND_LISTING if it succeeds,
1370 after which the client is expected to transmit the file, or any of the usual
1371 ERROR codes if it fails.
1374 RBIO (Read BIOgraphy)
1376 Receive from the server a named user's bio. This command should be passed
1377 a single argument - the name of the user whose bio is requested. RBIO returns
1378 LISTING_FOLLOWS plus the bio file if the user exists and has a bio on file,
1379 ERROR+NO_SUCH_USER if the named user does not exist, or ERROR+FILE_NOT_FOUND
1380 if the user exists but has no bio on file.
1382 ---------------------------------------------------------------------------
1383 The following commands are available only in Citadel/UX server version 4.11
1385 ---------------------------------------------------------------------------
1387 STEL (enter STEaLth mode)
1389 When in "stealth mode," a user will not show up in the "Who is online"
1390 listing (the RWHO server command). Only Aides may use stealth mode. The
1391 STEL command accepts one argument: a 1 indicating that the user wishes to
1392 enter stealth mode, or a 0 indicating that the user wishes to exit stealth
1393 mode. STEL returns OK if the command succeeded, ERROR+NOT_LOGGED_IN if no
1394 user is logged in, or ERROR+HIGHER_ACCESS_REQUIRED if the user is not an Aide.
1396 The STEL command also makes it so a user does not show up in the chat room
1400 LBIO (List users who have BIOs on file)
1402 This command is self-explanatory. Any user who has used EBIO to place a bio
1403 on file is listed. LBIO almost always returns LISTING_FOLLOWS followed by
1404 this listing, unless it experiences an internal error in which case ERROR
1408 MSG2 (read MeSsaGe, mode 2)
1410 MSG2 follows the same calling convention as MSG0. The difference between
1411 the two commands is that MSG2 outputs messages in standard RFC822 format
1412 rather than in Citadel/UX proprietary format.
1414 This command was implemented in order to make various gateway programs
1415 easier to implement, and to provide some sort of multimedia support in the
1416 future. Keep in mind that when this command is used, all messages will be
1417 output in fixed 80-column format.
1419 ---------------------------------------------------------------------------
1420 The following commands are available only in Citadel/UX server version 5.00
1422 ---------------------------------------------------------------------------
1424 MSG3 (read MeSsaGe, mode 3 -- internal command)
1426 MSG3 is for use by internal programs only and should not be utilized by
1427 user-mode clients. It does require IPGM authentication. MSG3 follows the
1428 same calling convention as the other MSG commands, but upon success returns
1429 BINARY_FOLLOWS followed by a data block containing the _raw_ message format
1433 ENT3 (ENTer message, mode 3 -- internal command)
1435 ENT3 is for use by internal programs only and should not be utilized by
1436 user-mode clients. It does require IPGM authentication. This command posts
1437 a raw message straight into the message base without modification or performing
1438 any checks. It accepts the following arguments:
1440 0 - Post flag. This should be set to 1 to post a message. If it is
1441 set to 0, the server only returns OK or ERROR (plus any flags describing
1442 the error) without reading in a message. This is used to verify the operation
1443 before actually transmitting a message.
1444 1 - Recipient. This argument is utilized only for private mail messages.
1445 It is ignored for public messages. It contains, of course, the name of the
1446 recipient of the message.
1447 2 - The size (in bytes) of the message to be transmitted.
1449 ENT3 returns OK to tell the client that a message can be posted, ERROR if
1450 there would be a problem with the operation, or SEND_BINARY followed by a byte
1451 count if it is expecting the message to be transmitted.
1454 TERM (TERMinate another session)
1456 In a multithreaded environment, it sometimes becomes necessary to terminate
1457 a session that is unusable for whatever reason. The TERM command performs
1458 this task. Naturally, only Aides can execute TERM. The command should be
1459 called with a single argument: the session ID (obtained from an RWHO command)
1460 of the session to be terminated.
1462 TERM returns OK if the session was terminated, or ERROR otherwise. Note that
1463 a client program is prohibited from terminating the session it is currently
1467 NSET (Network SETup commands)
1469 Aides may use this command to configure the networker. This command's
1470 parameters are passed directly to the 'netsetup' command line utility. If
1471 netsetup returns a non-zero exit code, ERROR is returned, along with the
1472 error message (if any). If netsetup returns a zero (success) exit code,
1473 LISTING_FOLLOWS is returned, followed by zero or more lines of output (since
1474 netsetup may have information to display, such as a room or node list) and
1475 the usual '000' listing terminator.
1478 DOWN (shut DOWN the server)
1480 This command, which may only be executed by an Aide, immediately shuts down
1481 the server. It is only implemented on servers on which such an operation is
1482 possible, such as a multithreaded Citadel engine. The server does not restart.
1483 DOWN returns OK if the user is allowed to shut down the server, in which case
1484 the client program should expect the connection to be immediately broken.
1487 SCDN (Schedule or Cancel a shutDowN)
1489 SCDN sets or clears the "scheduled shutdown" flag. Pass this command a 1 or
1490 0 to respectively set or clear the flag. When the "scheduled shutdown" flag is
1491 set, the server will be shut down when there are no longer any users logged in.
1492 Any value other than 0 or 1 will not change the flag, only report its state.
1493 No users will be kicked off the system, and in fact the server is still available
1494 for new connections. The command returns ERROR if it fails; otherwise, it
1495 returns OK followed by a number representing the current state of the flag.
1498 EMSG (Enter a system MeSsaGe)
1500 This is the opposite of the MESG command - it allows the creation and editing
1501 of system messages. The only argument passed to EMSG is the name of the
1502 file being transmitted. If the file exists in any system message directory
1503 on the server it will be overwritten, otherwise a new file is created. EMSG
1504 returns SEND_LISTING on success or ERROR+HIGHER_ACCESS_REQUIRED if the user
1507 Typical client software would use MESG to retrieve any existing message into
1508 an edit buffer, then present an editor to the user and run EMSG if the changes
1512 UIMG (Upload an IMaGe file)
1514 UIMG is complemenary to OIMG; it is used to upload an image to the server.
1515 The first parameter supplied to UIMG should be 0 if the client is only checking
1516 for permission to upload, or 1 if the client is actually attempting to begin
1517 the upload operation. The second argument is the name of the file to be
1518 transmitted. In Citadel/UX, the filename is converted to all lower case,
1519 appended with the characters ".gif", and stored in the "images" directory.
1521 UIMG returns OK if the client has permission to perform the requested upload,
1522 or ERROR+HIGHER_ACCESS_REQUIRED otherwise. If the client requested to begin
1523 the operation (first parameter set to 1), an upload file is opened, and the
1524 client should begin writing to it with WRIT commands, then close it with a
1527 The supplied filename should be one of:
1529 -> _userpic_ (Server will attempt to write to the user's online photo)
1530 -> Any of the "well known" filenames described in the writeup for the
1533 ----------------------------------------------
1534 The following are for citserver 5.02 and above
1535 ----------------------------------------------
1537 HCHG (Hostname CHanGe)
1539 HCHG is a command, usable by any user, that allows a user to change their RWHO
1540 host value. This will mask a client's originating hostname from normal
1541 users; access level 6 and higher see an entry right underneath the spoofed
1542 entry listing the actual hostname the user originates from.
1544 The format of an HCHG command is:
1548 If a HCHG command is successful, the value OK (200) is returned.
1551 RCHG (Roomname CHanGe)
1553 RCHG is a command, usable by any user, that allows a user to change their RWHO
1554 room value. This will mask a client's roomname from normal users; access
1555 level 6 and higher see an entry right underneath the spoofed entry listing
1556 the actual room the user is in.
1558 The format of an RCHG command is:
1562 If a RCHG command is successful, the value OK (200) is returned.
1565 UCHG (Username CHanGe)
1567 UCHG is an aide-level command which allows an aide to effectively change their
1568 username. If this value is blank, the user goes into stealth mode (see
1570 will show up as being from the real username in this mode, however. In
1571 addition, the RWHO listing will include both the spoofed and real usernames.
1573 The format of an UCHG command is:
1577 If a UCHG command is successful, the value OK (200) is returned.
1580 TIME (get server local TIME)
1582 TIME returns OK followed by the current time measured in seconds since
1583 00:00:00 GMT, Jan 1, 1970.
1585 This is used in allowing a client to calculate idle times.
1588 ----------------------------------------------
1589 The following are for citserver 5.11 and above
1590 ----------------------------------------------
1592 AGUP (Administrative Get User Parameters)
1593 ASUP (Administrative Set User Parameters)
1595 These commands are only executable by Aides and by server extensions running
1596 at system-level. They are used to get/set any and all parameters relating to
1597 a user account. AGUP requires only one argument: the name of the user in
1598 question. SGUP requires all of the parameters to be set. The parameters are
1599 as follows, and are common to both commands:
1603 2 - Flags (see citadel.h)
1608 7 - Timestamp of last call
1610 Upon success, AGUP returns OK followed by all these parameters, and ASUP
1611 simply returns OK. If the client has insufficient access to perform the
1612 requested operation, ERROR+HIGHER_ACCESS_REQUIRED is returned. If the
1613 requested user does not exist, ERROR+NO_SUCH_USER is returned.
1617 GPEX (Get Policy for message EXpiration)
1619 Returns the policy of the current room, floor, or site regarding the automatic
1620 purging (expiration) of messages. The following policies are available:
1621 0 - Fall back to the policy of the next higher level. If this is a room,
1622 use the floor's default policy. If this is a floor, use the system
1623 default policy. This is an invalid value for the system policy.
1624 1 - Do not purge messages automatically.
1625 2 - Purge by message count. (Requires a value: number of messages)
1626 3 - Purge by message age. (Requires a value: number of days)
1628 The format of this command is: GPEX <which>
1629 The value of <which> must be one of: "room" "floor" "site"
1631 If successful, GPEX returns OK followed by <policy>|<value>.
1635 SPEX (Set Polict for message EXpiration)
1637 Sets the policy of the current room, floor, or site regarding the automatic
1638 purging (expiration) of messages. See the writeup for the GPEX command for
1639 the list of available policies.
1641 The format of this command is: SPEX <which>|<policy>|<value>
1642 The value of <which> must be one of: "room" "floor" "site"
1644 If successful, GPEX returns OK; otherwise, an ERROR code is returned.
1648 CONF (get or set global CONFiguration options)
1650 Retrieves or sets various system-wide configuration and policy options. This
1651 command is only available to Aides. The sole parameter accepted is a command,
1652 which should be either GET or SET. If the GET command succeeds, CONF will
1653 return LISTING_FOLLOWS followed by the fields described below, one line at a
1654 time. If the SET command succeeds, CONF will return SEND_LISTING and expect
1655 the fields described below, one line at a time (don't worry about other fields
1656 being added in the future; if a 'short' configuration list is sent, the missing
1657 values at the end will be left unchanged on the system). If either command
1658 fails for any reason, ERROR is returned.
1660 The configuration lines are as follows:
1663 2. Fully qualified domain name
1664 3. Human-readable node name
1665 4. Landline telephone number of this system
1666 5. Flag (0 or 1) - creator of private room automatically becomes room aide
1667 6. Server connection idle timeout (in seconds)
1668 7. Initial access level for new users
1669 8. Flag (0 or 1) - require registration for new users
1670 9. Flag (0 or 1) - automatically move Problem User messages to twit room
1671 10. Name of twit room
1672 11. Text of <more> prompt
1673 12. Flag (0 or 1) - restrict access to Internet mail
1674 13. Geographic location of this system
1675 14. Name of the system administrator
1676 15. Number of maximum concurrent sessions allowed on the server
1677 16. Password for server-to-server networking
1678 17. Default purge time (in days) for users