1 SESSION LAYER PROTOCOL FOR CITADEL/UX
2 (c) 1995-1999 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
27 <ajc@uncnsrd.mt-kisco.ny.us>.
30 CONNECTING TO A SERVER
31 ----------------------
33 The protocols used below the session layer are beyond the scope of this
34 document, but we will briefly cover the methodology employed by Citadel/UX.
36 Citadel/UX offers Citadel BBS service using TCP/IP. It does so via a
37 multithreaded server listening on a TCP port. Older (4.xx) versions employed
38 an inetd-based server.
40 The port number officially assigned to Citadel by the IANA is TCP/504. Since
41 our session layer assumes a clean, reliable, sequenced connection, the use
42 of UDP would render the server unstable and unusable, so we stick with TCP.
45 GENERAL INFORMATION ABOUT THE SERVER
46 ------------------------------------
48 The server is connection-oriented and stateful: each client requires its own
49 connection to a server process, and when a command is sent, the client must
50 read the response, and then transfer data or change modes if necessary.
52 The session layer is very much like other Internet protocols such as SMTP
53 or NNTP. A client program sends one-line commands to the server, and the
54 server responds with a three-digit numeric result code followed by a message
55 describing what happened. This cycle continues until the end of the
58 Unlike protocols such as FTP, all data transfers occur in-band. This means
59 that the same connection that is used for exchange of client/server
60 messages, will also be used to transfer data back and forth. (FTP opens a
61 separate connection for data transfers.) We do this to allow the server to
62 function over transports which can only handle one session at a time (such
63 as a dialup connection).
69 The server will respond to all commands with a 3-digit result code, which
70 will be the first three characters on the line. The rest of the line may
71 contain a human-readable string explaining what happened. (Some client
72 software will display some of these strings to the user.)
74 The first digit is the most important. The following codes are defined for
75 this position: ERROR, OK, MORE_DATA, LISTING_FOLLOWS, and SEND_LISTING.
77 The second and third digits may provide a reason as to why a command
78 succeeded or failed. See ipcdef.h for the available codes.
80 ERROR means the command did not complete.
81 OK means the command executed successfully.
82 MORE_DATA means the command executed partially. Usually this means that
83 another command needs to be executed to complete the operation. For example,
84 sending the USER command to log in a user usually results in a MORE_DATA
85 result code, because the client needs to execute a PASS command to send the
86 password and complete the login.
87 LISTING_FOLLOWS means that after the server response, the server will
88 output a listing of some sort. The client *must* read the listing, whether
89 it wants to or not. The end of the listing is signified by the string
90 "000" on a line by itself.
91 SEND_LISTING is the opposite of LISTING_FOLLOWS. It means that the client
92 should begin sending a listing of some sort. The client *must* send something,
93 even if it is an empty listing. Again, the listing ends with "000" on a line
100 Zero or more parameters may be passed to a command. When more than one
101 parameter is passed to a command, they should be separated by the "|"
104 In this example, we're using the "SETU" command and passing three
105 parameters: 80, 24, and 260.
107 When the server spits out data that has parameters, if more than one
108 parameter is returned, they will be separated by the "|" symbol like
111 In this example, we just executed the "GETU" command, and it returned us
112 an OK result code (the '2' in the 200) and three parameters: 80, 24, and
119 This is a listing of all the commands that a Citadel/UX server can execute.
124 This command does nothing. It takes no arguments and always returns
125 OK. It is intended primarily for testing and development, but it might also
126 be used as a "keep alive" command to prevent the server from timing out, if
127 it's running over a transport that needs this type of thing.
130 ECHO (ECHO something)
132 This command also does nothing. It simply returns OK followed by whatever
138 Terminate the server connection. This command takes no arguments. It
139 returns OK and closes the connection immediately.
144 Log out the user without closing the server connection. It always returns
145 OK even if no user is logged in.
148 USER (send USER name)
150 The first step in logging in a user. This command takes one argument: the
151 name of the user to be logged in. If the user exists, a MORE_DATA return
152 code will be sent, which means the client should execute PASS as the next
153 command. If the user does not exist, ERROR is returned.
158 The second step in logging in a user. This command takes one argument: the
159 password for the user we are attempting to log in. If the password doesn't
160 match the correct password for the user we specified for the USER command,
161 or if a USER command has not been executed yet, ERROR is returned. If the
162 password is correct, OK is returned and the user is now logged in... and
163 most of the other server commands can now be executed. Along with OK, the
164 following parameters are returned:
166 0 - The user's name (in case the client wants the right upper/lower casing)
167 1 - The user's current access level
170 4 - Various flags (see citadel.h)
174 NEWU (create NEW User account)
176 This command creates a new user account and logs it in. The argument to
177 this command will be the name of the account. No case conversion is done
178 on the name. Note that the new account is installed with a default
179 configuration, and no password, so the client should immediately prompt the
180 user for a password and install it with the SETP command as soon as this
181 command completes. This command returns OK if the account was created and
182 logged in, or ERROR if another user already exists with this name. If OK,
183 it will also return the same parameters that PASS returns.
186 SETP (SET new Password)
188 This command sets a new password for the currently logged in user. The
189 argument to this command will be the new password. The command always
190 returns OK, unless the client is not logged in, in which case it will return
194 LKRN (List Known Rooms with New messages)
196 List known rooms with new messages. If the client is not logged in, ERROR
197 is returned. Otherwise, LISTING_FOLLOWS is returned, followed by the room
198 listing. Each line in the listing contains the full name of a room, followed
199 by the '|' symbol, and then a number that may contain the following bits:
202 #define QR_PERMANENT 1 /* Room does not purge */
203 #define QR_PRIVATE 4 /* Set for any type of private room */
204 #define QR_PASSWORDED 8 /* Set if there's a password too */
205 #define QR_GUESSNAME 16 /* Set if it's a guessname room */
206 #define QR_DIRECTORY 32 /* Directory room */
207 #define QR_UPLOAD 64 /* Allowed to upload */
208 #define QR_DOWNLOAD 128 /* Allowed to download */
209 #define QR_VISDIR 256 /* Visible directory */
210 #define QR_ANONONLY 512 /* Anonymous-Only room */
211 #define QR_ANON2 1024 /* Anonymous-Option room */
212 #define QR_NETWORK 2048 /* Shared network room */
213 #define QR_PREFONLY 4096 /* Preferred status needed to enter */
214 #define QR_READONLY 8192 /* Aide status required to post */
217 Other bits may be defined in the future. The listing terminates, as with
218 all listings, with "000" on a line by itself.
220 Starting with version 4.01 and above, floors are supported. The first
221 argument to LKRN should be the number of the floor to list rooms from. Only
222 rooms from this floor will be listed. If no arguments are passed to LKRN, or
223 if the floor number requested is (-1), rooms on all floors will be listed.
225 The third field displayed on each line is the number of the floor the room
226 is on. The LFLR command should be used to associate floor numbers with
229 The fourth field displayed on each line is a "room listing order." Unless
230 there is a compelling reason not to, clients should sort any received room
231 listings by this value.
235 LKRO (List Known Rooms with Old [no new] messages)
237 This follows the same usage and format as LKRN.
240 LZRM (List Zapped RooMs)
242 This follows the same usage and format as LKRN and LKRO.
245 LKRA (List All Known Rooms)
247 Same format. Lists all known rooms, with or without new messages.
250 LRMS (List all accessible RooMS)
252 Again, same format. This command lists all accessible rooms, known and
253 forgotten, with and without new messages. It does not, however, list
254 inaccessible private rooms.
257 GETU (GET User configuration)
259 This command retrieves the screen dimensions and user options for the
260 currently logged in account. ERROR will be returned if no user is logged
261 in, of course. Otherwise, OK will be returned, followed by three parameters.
262 The first parameter is the user's screen width, the second parameter is the
263 user's screen height, and the third parameter is a bag of bits with the
266 #define US_LASTOLD 16 /* Print last old message with new */
267 #define US_EXPERT 32 /* Experienced user */
268 #define US_UNLISTED 64 /* Unlisted userlog entry */
269 #define US_NOPROMPT 128 /* Don't prompt after each message */
270 #define US_DISAPPEAR 512 /* Use "disappearing msg prompts" */
271 #define US_PAGINATOR 2048 /* Pause after each screen of text */
273 There are other bits, too, but they can't be changed by the user (see below).
276 SETU (SET User configuration)
278 This command does the opposite of SETU: it takes the screen dimensions and
279 user options (which were probably obtained with a GETU command, and perhaps
280 modified by the user) and writes them to the user account. This command
281 should be passed three parameters: the screen width, the screen height, and
282 the option bits (see above).
284 Note that there exist bits here which are not listed in this document. Some
285 are flags that can only be set by Aides or the system administrator. SETU
286 will ignore attempts to toggle these bits. There also may be more user
287 settable bits added at a later date. To maintain later downward compatibility,
288 the following procedure is suggested:
290 1. Execute GETU to read the current flags
291 2. Toggle the bits that we know we can toggle
292 3. Execute SETU to write the flags
294 If we are passed a bit whose meaning we don't know, it's best to leave it
295 alone, and pass it right back to the server. That way we can use an old
296 client on a server that uses an unknown bit without accidentally clearing
297 it every time we set the user's configuration.
302 This command is used to goto a new room. When the user first logs in (login
303 is completed after execution of the PASS command) this command is
304 automatically and silently executed to take the user to the first room in the
305 system (usually called the Lobby).
307 This command can be passed one or two parameters. The first parameter is,
308 of course, the name of the room. Although it is not case sensitive, the
309 full name of the room must be used. Wildcard matching or unique string
310 matching of room names should be the responsibility of the client.
312 Note that the reserved room name "_BASEROOM_" can be passed to the server
313 to cause the goto command to take the user to the first room in the system,
314 traditionally known as the Lobby>. As long as a user is logged in, a
315 GOTO command to _BASEROOM_ is guaranteed to succeed. This is useful to
316 allow client software to return to the base room when it doesn't know
319 There are also two additional reserved room names:
320 "_MAIL_" translates to the system's designated room for e-mail messages.
321 "_BITBUCKET_" goes to whatever room has been chosen for messages
324 The second (and optional) parameter is a password, if one is required for
325 access to the room. This allows for all types of rooms to be accessed via
326 this command: for public rooms, invitation-only rooms to which the user
327 has access, and preferred users only rooms to which the user has access, the
328 room will appear in a room listing. For guess-name rooms, this command
329 will work transparently, adding the room to the user's known room list when
330 it completes. For passworded rooms, access will be denied if the password
331 is not supplied or is incorrect, or the command will complete successfully
332 if the password is correct.
334 The possible result codes are:
336 OK - The command completed successfully. User is now in the room.
337 (See the list of returned parameters below)
339 ERROR - The command did not complete successfully. Check the second and
340 third positions of the result code to find out what happened:
342 NOT_LOGGED_IN - Of course you can't go there. You didn't log in.
343 PASSWORD_REQUIRED - Either a password was not supplied, or the supplied
344 password was incorrect.
345 NO_SUCH_ROOM - The requested room does not exist.
347 The typical procedure for entering a passworded room would be:
349 1. Execute a GOTO command without supplying any password.
350 2. ERROR+PASSWORD_REQUIRED will be returned. The client now knows that
351 the room is passworded, and prompts the user for a password.
352 3. Execute a GOTO command, supplying both the room name and the password.
353 4. If OK is returned, the command is complete. If, however,
354 ERROR+PASSWORD_REQUIRED is still returned, tell the user that the supplied
355 password was incorrect. The user remains in the room he/she was previously
358 When the command succeeds, these parameters are returned:
359 0. The name of the room
360 1. Number of unread messages in this room
361 2. Total number of messages in this room
362 3. Info flag: set to nonzero if the user needs to read this room's info
363 file (see RINF command below)
364 4. Various flags associated with this room. (See LKRN cmd above)
365 5. The highest message number present in this room
366 6. The highest message number the user has read in this room
367 7. Boolean flag: 1 if this is a Mail> room, 0 otherwise.
368 8. Aide flag: 1 if the user is either the Room Aide for this room, *or* is
369 a regular Aide (this makes access checks easy).
370 9. The number of new Mail messages the user has (useful for alerting the
371 user to the arrival of new mail during a session)
372 10. The floor number this room resides on
375 MSGS (get pointers to MeSsaGeS in this room)
377 This command obtains a listing of all the messages in the current room
378 which the client may request. This command may be passed a single parameter:
379 either "all", "old", or "new" to request all messages, only old messages, or
380 new messages. Or it may be passed two parameters: "last" plus a number, in
381 which case that many message pointers will be returned, or "first" plus a
382 number, for the corresponding effect. If no parameters are specified, "all"
385 In Citadel/UX 5.00 and above, the client may also specify "gt" plus a number,
386 to list all messages in the current room with a message number greater than
389 The third argument, valid only in Citadel/UX 5.60 and above, may be either
390 0 or 1. If it is 1, this command behaves differently: before a listing is
391 returned, the client must transmit a list of fields to search for. The field
392 headers are listed below in the writeup for the "MSG0" command.
394 This command can return three possible results. An ERROR code may be returned
395 if no user is currently logged in or if something else went wrong. Otherwise,
396 LISTING_FOLLOWS will be returned, and the listing will consist of zero or
397 more message numbers, one per line. The listing ends, as always, with the
398 string "000" alone on a line by itself. The listed message numbers can be used
399 to request messages from the system. If "search mode" is being used, the
400 server will return START_CHAT_MODE, and the client is expected to transmit
401 the search criteria, and then read the message list.
403 Since this is somewhat complex, here are some examples:
405 Example 1: Read all new messages
408 Server: 100 Message list...
414 Example 2: Read the last five messages
417 Server: 100 Message list...
425 Example 3: Read all messages written by "IGnatius T Foobar"
428 Server: 800 Send template then receive message list
429 Client: from|IGnatius T Foobar
443 Note that in "search mode" the client may specify any number of search
444 criteria. These criteria are applied with an AND logic.
448 MSG0 (read MeSsaGe, mode 0)
450 This is a command used to read the text of a message. "Mode 0" implies that
451 other MSG commands (MSG1, MSG2, etc.) will probably be added later on to read
452 messages in more robust formats. This command should be passed two arguments.
453 The first is the message number of the message being requested. In server
454 version 4.04 and above, the second argument may be set to either 0 to read the
455 entire message, or 1 to read the headers only.
457 The server should, of course, make sure that the client actually has access
458 to the message being requested before honoring this request. Citadel/UX does
459 so by checking the message number against the contents of the current room. If
460 it's not there, the request is denied.
462 If the request is denied, an ERROR code will be returned. Otherwise, the
463 LISTING_FOLLOWS code will be returned, followed by the contents of the message.
464 The following fields may be sent:
466 type= Formatting type. The currently defined types are:
467 0 = "traditional" Citadel formatting. This means that newlines should be
468 treated as spaces UNLESS the first character on the next line is a space. In
469 other words, only indented lines should generate a newline on the user's screen
470 when the message is being displayed. This allows a message to be formatted to
471 the reader's screen width. It also allows the use of proportional fonts.
472 1 = a simple fixed-format message. The message should be displayed to
473 the user's screen as is, preferably in a fixed-width font that will fit 80
475 4 = MIME format message. The message text is expected to contain a header
476 with the "Content-type:" directive (and possibly others).
478 msgn= The message ID of this message on the system it originated on.
479 path= An e-mailable path back to the user who wrote the message.
481 time= The date and time of the message, in Unix format (the number of
482 seconds since midnight on January 1, 1970, GMT).
484 from= The name of the author of the message.
485 rcpt= If the message is a private e-mail, this is the recipient.
486 room= The name of the room the message originated in.
487 node= The short node name of the system this message originated on.
488 hnod= The long node name of the system this message originated on.
489 zaps= The id/node of a message which this one zaps (supersedes).
491 text Note that there is no "=" after the word "text". This string
492 signifies that the message text begins on the next line.
495 WHOK (WHO Knows room)
497 This command is available only to Aides. ERROR+HIGHER_ACCESS_REQUIRED will
498 be returned if the user is not an Aide. Otherwise, it returns
499 LISTING_FOLLOWS and then lists, one user per line, every user who has
500 access to the current room.
503 INFO (get server INFO)
505 This command will *always* return LISTING_FOLLOWS and then print out a
506 listing of zero or more strings. Client software should be written to expect
507 anywhere from a null listing to an infinite number of lines, to allow later
508 backward compatibility. The current implementation defines the following
509 parts of the listing:
511 Line 1 - Your unique session ID on the server
512 Line 2 - The node name of the server BBS
513 Line 3 - Human-readable node name of the server BBS
514 Line 4 - The fully-qualified domain name (FQDN) of the server
515 Line 5 - The name of the server software, i.e. "Citadel/UX 4.00"
516 Line 6 - (The revision level of the server code) * 100
517 Line 7 - The geographical location of the BBS (city and state if in the US)
518 Line 8 - The name of the system administrator
519 Line 9 - A number identifying the server type (see below)
520 Line 10 - The text of the system's paginator prompt
521 Line 11 - Floor Flag. 1 if the system supports floors, 0 otherwise.
522 Line 12 - Paging level. 0 if the system only supports inline paging,
523 1 if the system supports "extended" paging (check-only and
524 multiline modes). See the SEXP command for further information.
526 *** NOTE! *** The "server type" code is intended to promote global
527 compatibility in a scenario in which developers have added proprietary
528 features to their servers or clients. We are attempting to avoid a future
529 situation in which users need to keep different client software around for
530 each BBS they use. *Please*, if you are a developer and plan to add
531 proprietary features:
533 -> Your client programs should still be able to utilize servers other than
535 -> Clients other than your own should still be able to utilize your server,
536 even if your proprietary extensions aren't supported.
537 -> Please contact Art Cancro <ajc@uncnsrd.mt-kisco.ny.us> and obtain a unique
538 server type code, which can be assigned to your server program.
539 -> If you document what you did in detail, perhaps it can be added to a
540 future release of the Citadel/UX program, so everyone can enjoy it. Better
541 yet, just work with the Citadel development team on the main source tree.
543 If everyone follows this scheme, we can avoid a chaotic situation with lots
544 of confusion about which client program works with which server, etc. Client
545 software can simply check the server type (and perhaps the revision level)
546 to determine ahead of time what commands may be utilized.
548 Please refer to "developers.txt" for information on what codes belong to whom.
552 RDIR (Read room DIRectory)
554 Use this command to read the directory of a directory room. ERROR+NOT_HERE
555 will be returned if the room has no directory, or some other error; ERROR +
556 HIGHER_ACCESS_REQUIRED will be returned if the room's directory is not
557 visible and the user does not have Aide or Room Aide privileges; otherwise
558 LISTING_FOLLOWS will be returned, followed by the room's directory. Each
559 line of the directory listing will contain three fields: a filename, the
560 length of the file, and a description.
562 The server message contained on the same line with LISTING_FOLLOWS will
563 contain the name of the system and the name of the directory, such as:
564 uncnsrd.mt-kisco.ny.us|/usr/bbs/files/my_room_directory
567 SLRP (Set Last-message-Read Pointer)
569 This command is used to mark messages as having been read. Its sole parameter
570 is the number of the last message that has been read. This allows the pointer
571 to be set at any arbitrary point in the room. Optionally, the parameter
572 "highest" may be used instead of a message number, to set the pointer to the
573 number of the highest message in the room, effectively marking all messages
574 in the room as having been read (ala the Citadel <G>oto command).
576 The command will return OK if the pointer was set, or ERROR if something
577 went wrong. If OK is returned, it will be followed by a single argument
578 containing the message number the last-read-pointer was set to.
581 INVT (INViTe a user to a room)
583 This command may only be executed by Aides, or by the room aide for the
584 current room. It is used primarily to add users to invitation-only rooms,
585 but it may also be used in other types of private rooms as well. Its sole
586 parameter is the name of the user to invite.
588 The command will return OK if the operation succeeded, or ERROR if it did
589 not. ERROR+HIGHER_ACCESS_REQUIRED may also be returned if the operation
590 would have been possible if the user had higher access, and ERROR+NOT_HERE
591 may be returned if the room is not a private room.
594 KICK (KICK a user out of a room)
596 This is the opposite of INVT: it is used to kick a user out of a private
597 room. It can also be used to kick a user out of a public room, but the
598 effect will only be the same as if the user <Z>apped the room - a non-stupid
599 user can simply un-zap the room to get back in.
602 GETR (GET Room attributes)
604 This command is used for editing the various attributes associated with a
605 room. A typical "edit room" command would work like this:
606 1. Use the GETR command to get the current attributes
607 2. Change some of them around
608 3. Use SETR (see below) to save the changes
609 4. Possibly also change the room aide using the GETA and SETA commands
611 GETR takes no arguments. It will only return OK if the SETR command will
612 also return OK. This allows client software to tell the user that he/she
613 can't edit the room *before* going through the trouble of actually doing the
614 editing. Possible return codes are:
616 ERROR+NOT_LOGGED_IN - No user is logged in.
617 ERROR+HIGHER_ACCESS_REQUIRED - Not enough access. Typically, only aides
618 and the room aide associated with the current room, can access this command.
619 ERROR+NOT_HERE - Lobby>, Mail>, and Aide> cannot be edited.
620 OK - Command succeeded. Parameters are returned.
622 If OK is returned, the following parameters will be returned as well:
624 0. The name of the room
625 1. The room's password (if it's a passworded room)
626 2. The name of the room's directory (if it's a directory room)
627 3. Various flags (bits) associated with the room (see LKRN cmd above)
628 4. The floor number on which the room resides
629 5. The room listing order
632 SETR (SET Room attributes)
634 This command sets various attributes associated with the current room. It
635 should be passed the following arguments:
637 0. The name of the room
638 1. The room's password (if it's a passworded room)
639 2. The name of the room's directory (if it's a directory room)
640 3. Various flags (bits) associated with the room (see LKRN cmd above)
641 4. "Bump" flag (see below)
642 5. The floor number on which the room should reside
643 6. The room listing order
645 *Important: You should always use GETR to retrieve the current attributes of
646 the room, then change what you want to change, and then use SETR to write it
647 all back. This is particularly important with respect to the flags: if a
648 particular bit is set, and you don't know what it means, LEAVE IT ALONE and
649 only toggle the bits you want to toggle. This will allow for upward
652 If the room is a private room, you have the option of causing all users who
653 currently have access, to forget the room. If you want to do this, set the
654 "bump" flag to 1, otherwise set it to 0.
659 This command is used to get the name of the Room Aide for the current room.
660 It will return ERROR+NOT_LOGGED_IN if no user is logged in, ERROR if there
661 is no current room, or OK if the command succeeded. Along with OK there will
662 be returned one parameter: the name of the Room Aide.
667 The opposite of GETA, used to set the Room Aide for the current room. One
668 parameter should be passed, which is the name of the user who is to be the
669 new Room Aide. Under Citadel/UX, this command may only be executed by Aides
670 and by the *current* Room Aide for the room. Return codes possible are:
671 ERROR+NOT_LOGGED_IN (Not logged in.)
672 ERROR+HIGHER_ACCESS_REQUIRED (Higher access required.)
673 ERROR+NOT_HERE (No current room, or room cannot be edited.
674 Under Citadel/UX, the Lobby> Mail> and Aide> rooms are non-editable.)
675 OK (Command succeeded.)
678 ENT0 (ENTer message, mode 0)
680 This command is used to enter messages into the system. It accepts four
683 0 - Post flag. This should be set to 1 to post a message. If it is
684 set to 0, the server only returns OK or ERROR (plus any flags describing
685 the error) without reading in a message. Client software should, in fact,
686 perform this operation at the beginning of an "enter message" command
687 *before* starting up its editor, so the user does not end up typing a message
688 in vain that will not be permitted to be saved. If it is set to 2, the
689 server will accept an "apparent" post name if the user is privileged enough.
690 This post name is arg 4.
691 1 - Recipient. This argument is utilized only for private mail messages.
692 It is ignored for public messages. It contains, of course, the name of the
693 recipient of the message.
694 2 - Anonymous flag. This argument is ignored unless the room allows
695 anonymous messages. In such rooms, this flag may be set to 1 to flag a
696 message as anonymous, otherwise 0 for a normal message.
697 3 - Format type. Any valid Citadel/UX format type may be used (this will
698 typically be 0; see the MSG0 command above).
699 4 - Post name. When postflag is 2, this is the name you are posting as.
700 This is an Aide only command.
702 Possible result codes:
703 OK - The request is valid. (Client did not set the "post" flag, so the
704 server will not read in message text.) If the message is an e-mail with
705 a recipient, the text that follows the OK code will contain the exact name
706 to which mail is being sent. The client can display this to the user. The
707 implication here is that the name that the server returns will contain the
708 correct upper and lower case characters. In addition, if the recipient is
709 having his/her mail forwarded, the forwarding address will be returned.
710 SEND_LISTING - The request is valid. The client should now transmit
711 the text of the message (ending with a 000 on a line by itself, as usual).
712 ERROR - Miscellaneous error. (Explanation probably follows.)
713 ERROR + NOT_LOGGED_IN - Not logged in.
714 ERROR + HIGHER_ACCESS_REQUIRED - Higher access is required. An
715 explanation follows, worded in a form that can be displayed to the user.
716 ERROR + NO_SUCH_USER - The specified recipient does not exist.
719 RINF (read Room INFormation file)
721 Each room has associated with it a text file containing a description of
722 the room, perhaps containing its intended purpose or other important
723 information. The info file for the Lobby> (the system's base room) is
724 often used as a repository for system bulletins and the like.
726 This command, which accepts no arguments, is simply used to read the info
727 file for the current room. It will return LISTING_FOLLOWS followed by
728 the text of the message (always in format type 0) if the request can be
729 honored, or ERROR if no info file exists for the current room (which is
730 often the case). Other error description codes may accompany this result.
732 When should this command be used? This is, of course, up to the discretion
733 of client software authors, but in Citadel it is executed in two situations:
734 the first time the user ever enters a room; and whenever the contents of the
735 file change. The latter can be determined from the result of a GOTO command,
736 which will tell the client whether the file needs to be read (see GOTO above).
739 DELE (DELEte a message)
741 Delete a message from the current room. The one argument that should be
742 passed to this command is the message number of the message to be deleted.
743 The return value will be OK if the message was deleted, or an ERROR code.
744 If the delete is successful, the message's reference count is decremented, and
745 if the reference count reaches zero, the message is removed from the message
749 MOVE (MOVE or copy a message to a different room)
751 Move a message to a different room. The two arguments that should be passed
752 to this command are the message number of the message to be deleted, and the
753 name of the target room. If the operation succeeds, the message will be
754 deleted from the current room and moved to the target room. An ERROR code
755 usually means that either the user does not have permission to perform this
756 operation, or that the target room does not exist.
758 In Citadel/UX 5.55 and above, a third argument may be specified: 0 or 1 to
759 designate whether the message should be moved (0) or copied (1) to the target
760 room. In the case of a "copy" operation, the message's reference count is
761 incremented, and a pointer to the message will exist in both the source *and*
762 target rooms. In the case of a "move" operation, the message pointer is
763 deleted from the source room and the reference count remains the same.
766 KILL (KILL current room)
768 This command deletes the current room. It accepts a single argument, which
769 should be nonzero to actually delete the room, or zero to merely check
770 whether the room can be deleted.
772 Once the room is deleted, the current room is undefined. It is suggested
773 that client software immediately GOTO another room (usually _BASEROOM_)
774 after this command completes.
776 Possible return codes:
778 OK - room has been deleted (or, if checking only, request is valid).
779 ERROR+NOT_LOGGED_IN - no user is logged in.
780 ERROR+HIGHER_ACCESS_REQUIRED - not enough access to delete rooms.
781 ERROR+NOT_HERE - this room can not be deleted.
784 CRE8 (CRE[ate] a new room)
786 This command is used to create a new room. Like some of the other
787 commands, it provides a mechanism to first check to see if a room can be
788 created before actually executing the command. CRE8 accepts the following
791 0 - Create flag. Set this to 1 to actually create the room. If it is
792 set to 0, the server merely checks that there is a free slot in which to
793 create a new room, and that the user has enough access to create a room. It
794 returns OK if the client should go ahead and prompt the user for more info,
795 or ERROR or ERROR+HIGHER_ACCESS_REQUIRED if the command will not succeed.
796 1 - Name for new room.
797 2 - Access type for new room:
799 1 - Private; can be entered by guessing the room's name
800 2 - Private; can be entered by knowing the name *and* password
801 3 - Private; invitation only (sometimes called "exclusive")
802 3 - Password for new room (if it is a type 2 room)
803 4 - Floor number on which the room should reside (optional)
805 If the create flag is set to 1, the room is created (unless something
806 went wrong and an ERROR return is sent), and the server returns OK, but
807 the session is **not** automatically sent to that room. The client still
808 must perform a GOTO command to go to the new room.
811 FORG (FORGet the current room)
813 This command is used to forget (zap) the current room. For those not
814 familiar with Citadel, this terminology refers to removing the room from
815 a user's own known rooms list, *not* removing the room itself. After a
816 room is forgotten, it no longer shows up in the user's known room list,
817 but it will exist in the user's forgotten room list, and will return to the
818 known room list if the user goes to the room (in Citadel, this is
819 accomplished by explicitly typing the room's name in a <.G>oto command).
821 The command takes no arguments. If the command cannot execute for any
822 reason, ERROR will be returned. ERROR+NOT_LOGGED_IN or ERROR+NOT_HERE may
823 be returned as they apply.
825 If the command succeeds, OK will be returned. At this point, the current
826 room is **undefined**, and the client software is responsible for taking
827 the user to another room before executing any other room commands (usually
828 this will be _BASEROOM_ since it is always there).
831 MESG (read system MESsaGe)
833 This command is used to display system messages and/or help files. The
834 single argument it accepts is the name of the file to display. IT IS CASE
835 SENSITIVE. Citadel/UX looks for these files first in the "messages"
836 subdirectory and then in the "help" subdirectory.
838 If the file is found, LISTING_FOLLOWS is returned, followed by a pathname
839 to the file being displayed. Then the message is printed, in format type 0
840 (see MSG0 command for more information on this). If the file is not found,
843 There are some "well known" names of system messages which client software
844 may expect most servers to carry:
846 hello - Welcome message, to be displayed before the user logs in.
847 changepw - To be displayed whenever the user is prompted for a new
848 password. Warns about picking guessable passwords and such.
849 register - Should be displayed prior to the user entering registration.
850 Warnings about not getting access if not registered, etc.
851 help - Main system help file.
852 goodbye - System logoff banner; display when user logs off.
853 roomaccess - Information about how public rooms and different types of
854 private rooms function with regards to access.
855 unlisted - Tells users not to choose to be unlisted unless they're
856 really paranoid, and warns that aides can still see
857 unlisted userlog entries.
859 Citadel/UX provides these for the Citadel/UX Unix text client. They are
860 probably not very useful for other clients:
862 mainmenu - Main menu (when in idiot mode).
867 saveopt - Options to save a message, abort, etc.
868 entermsg - Displayed just before a message is entered, when in
872 GNUR (Get Next Unvalidated User)
874 This command shows the name of a user that needs to be validated. If there
875 are no unvalidated users, OK is returned. Otherwise, MORE_DATA is returned
876 along with the name of the first unvalidated user the server finds. All of
877 the usual ERROR codes may be returned as well (for example, if the user is
878 not an Aide and cannot validate users).
880 A typical "Validate New Users" command would keep executing this command,
881 and then validating each user it returns, until it returns OK when all new
882 users have been validated.
885 GREG (Get REGistration for user)
887 This command retrieves the registration info for a user, whose name is the
888 command's sole argument. All the usual error messages can be returned. If
889 the command succeeds, LISTING_FOLLOWS is returned, followed by the user's name
890 (retrieved from the userlog, with the right upper and lower case etc.) The
891 contents of the listing contains one field per line, followed by the usual
892 000 on the last line.
894 The following lines are defined. Others WILL be added in the futre, so all
895 software should be written to read the lines it knows about and then ignore
901 Line 4: Street address or PO Box
902 Line 5: City/town/village/etc.
903 Line 6: State/province/etc.
905 Line 8: Telephone number
907 Line 10: Internet e-mail address
909 Users without Aide privileges may retrieve their own registration using
910 this command. This can be accomplished either by passing the user's own
911 name as the argument, or the string "_SELF_". The command will always
912 succeed when used in this manner, unless no user is logged in.
917 This command is used to validate users. Obviously, it can only be executed
918 by users with Aide level access. It should be passed two parameters: the
919 name of the user to validate, and the desired access level
921 If the command succeeds, OK is returned. The user's access level is changed
922 and the "need validation" bit is cleared. If the command fails for any
923 reason, ERROR, ERROR+NO_SUCH_USER, or ERROR+HIGHER_ACCESS_REQUIRED will be
927 EINF (Enter INFo file for room)
929 Transmit the info file for the current room with this command. EINF uses
930 a boolean flag (1 or 0 as the first and only argument to the command) to
931 determine whether the client actually wishes to transmit a new info file, or
932 is merely checking to see if it has permission to do so.
934 If the command cannot succeed, it returns ERROR.
935 If the client is only checking for permission, and permission will be
936 granted, OK is returned.
937 If the client wishes to transmit the new info file, SEND_LISTING is
938 returned, and the client should transmit the text of the info file, ended
939 by the usual 000 on a line by itself.
944 This is a simple user listing. It always succeeds, returning
945 LISTING_FOLLOWS followed by zero or more user records, 000 terminated. The
946 fields on each line are as follows:
951 4. Date/time of last login (Unix format)
954 7. Password (listed only if the user requesting the list is an Aide)
956 Unlisted entries will also be listed to Aides logged into the server, but
957 not to ordinary users.
960 REGI (send REGIstration)
962 Clients will use this command to transmit a user's registration info. If
963 no user is logged in, ERROR+NOT_LOGGED_IN is returned. Otherwise,
964 SEND_LISTING is returned, and the server will expect the following information
965 (terminated by 000 on a line by itself):
968 Line 2: Street address or PO Box
969 Line 3: City/town/village/etc.
970 Line 4: State/province/etc.
972 Line 6: Telephone number
973 Line 7: e-mail address
976 CHEK (CHEcK various things)
978 When logging in, there are various things that need to be checked. This
979 command will return ERROR+NOT_LOGGED_IN if no user is logged in. Otherwise
980 it returns OK and the following parameters:
982 0: Number of new private messages in Mail>
983 1: Nonzero if the user needs to register
984 2: (Relevant to Aides only) Nonzero if new users require validation
989 This command deletes a file from the room's directory, if there is one. The
990 name of the file to delete is the only parameter to be supplied. Wildcards
991 are not acceptable, and any slashes in the filename will be converted to
992 underscores, to prevent unauthorized access to neighboring directories. The
993 possible return codes are:
995 OK - Command succeeded. The file was deleted.
996 ERROR+NOT_LOGGED_IN - Not logged in.
997 ERROR+HIGHER_ACCESS_REQUIRED - Not an Aide or Room Aide.
998 ERROR+NOT_HERE - There is no directory in this room.
999 ERROR+FILE_NOT_FOUND - Requested file was not found.
1004 This command is similar to DELF, except that it moves a file (and its
1005 associated file description) to another room. It should be passed two
1006 parameters: the name of the file to move, and the name of the room to move
1007 the file to. All of the same return codes as DELF may be returned, and also
1008 one additional one: ERROR+NO_SUCH_ROOM, which means that the target room
1009 does not exist. ERROR+NOT_HERE could also mean that the target room does
1010 not have a directory.
1013 NETF (NETwork send a File)
1015 This command is similar to MOVF, except that it attempts to send a file over
1016 the network to another system. It should be passed two parameters: the name
1017 of the file to send, and the node name of the system to send it to. All of
1018 the same return codes as MOVF may be returned, except for ERROR+NO_SUCH_ROOM.
1019 Instead, ERROR+NO_SUCH_SYSTEM may be returned if the name of the target
1022 The name of the originating room will be sent along with the file. Most
1023 implementations will look for a room with the same name at the receiving end
1024 and attempt to place the file there, otherwise it goes into a bit bucket room
1025 for miscellaneous files. This is, however, beyond the scope of this document;
1026 see elsewhere for more details.
1029 RWHO (Read WHO's online)
1031 Displays a list of all users connected to the server. No error codes are
1032 ever returned. LISTING_FOLLOWS will be returned, followed by zero or more
1033 lines containing the following three fields:
1035 0 - Session ID. Citadel/UX fills this with the pid of a server program.
1037 2 - The name of the room the user is currently in. This field might not
1038 be displayed (for example, if the user is in a private room) or it might
1039 contain other information (such as the name of a file the user is
1041 3 - (server v4.03 and above) The name of the host the client is connecting
1042 from, or "localhost" if the client is local.
1043 4 - (server v4.04 and above) Description of the client software being used
1044 5 - The last time, locally to the server, that a command was received from
1045 this client (Note: NOOP's don't count)
1046 6 - The last command received from a client. (NOOP's don't count)
1047 7 - Session flags. These are: + (spoofed address), - (STEALTH mode), *
1048 (posting) and . (idle). (Citserver 5.02 and above)
1050 The listing is terminated, as always, with the string "000" on a line by
1054 OPEN (OPEN a file for download)
1056 This command is used to open a file for downloading. Only one download
1057 file may be open at a time. The only argument to this command is the name
1058 of the file to be opened. The user should already be in the room where the
1059 file resides. Possible return codes are:
1062 ERROR+NOT_HERE (no directory in this room)
1063 ERROR+FILE_NOT_FOUND (could not open the file)
1067 If the file is successfully opened, OK will be returned, along with the
1068 size (in bytes) of the file, the time of last modification (if applicable),
1069 the filename (if known), and the MIME type of the file (if known).
1072 CLOS (CLOSe the download file)
1074 This command is used to close the download file. It returns OK if the
1075 file was successfully closed, or ERROR if there wasn't any file open in the
1079 READ (READ from the download file)
1081 Two arguments are passed to this command. The first is the starting position
1082 in the download file, and the second is the total number of bytes to be
1083 read. If the operation can be performed, BINARY_FOLLOWS will be returned,
1084 along with the number of bytes to follow. Then, immediately following the
1085 newline, will be that many bytes of binary data. The client *must* read
1086 exactly that number of bytes, otherwise the client and server will get out
1089 If the operation cannot be performed, any of the usual error codes will be
1093 UOPN (OPeN a file for Uploading)
1095 This command is similar to OPEN, except that this one is used when the
1096 client wishes to upload a file to the server. The first argument is the name
1097 of the file to create, and the second argument is a one-line comment
1098 describing the contents of the file. Only one upload file may be open at a
1099 time. Possible return codes are:
1102 ERROR+NOT_HERE (no directory in this room)
1103 ERROR+FILE_NOT_FOUND (a name must be specified)
1104 ERROR (miscellaneous errors)
1105 ERROR+ALREADY_EXISTS (a file with the same name already exists)
1108 If OK is returned, the command has succeeded and writes may be performed.
1111 UCLS (CLoSe the Upload file)
1113 Close the file opened with UOPN. An argument of "1" should be passed to
1114 this command to close and save the file; otherwise, the transfer will be
1115 considered aborted and the file will be deleted. This command returns OK
1116 if the operation succeeded or ERROR if it did not.
1119 WRIT (WRITe to the upload file)
1121 If an upload file is open, this command may be used to write to it. The
1122 argument passed to this command is the number of bytes the client wishes to
1123 transmit. An ERROR code will be returned if the operation cannot be
1126 If the operation can be performed, SEND_BINARY will be returned, followed
1127 by the number of bytes the server is expecting. The client must then transmit
1128 exactly that number of bytes. Note that in the current implementation, the
1129 number of bytes the server is expecting will always be the number of bytes
1130 the client requested to transmit, but the client software should never assume
1131 that this will always happen, in case changes are made later.
1134 QUSR (Query for a USeR)
1136 This command is used to check to see if a particular user exists. The only
1137 argument to this command is the name of the user being searched for. If
1138 the user exists, OK is returned, along with the name of the user in the userlog
1139 (so the client software can learn the correct upper/lower casing of the name
1140 if necessary). If the user does not exist, ERROR+NO_SUCH_USER is returned.
1141 No login or current room is required to utilize this command.
1144 OIMG (Open an IMaGe file)
1146 Open an image (graphics) file for downloading. Once opened, the file can be
1147 read as if it were a download file. This implies that an image and a download
1148 cannot be opened at the same time. OIMG returns the same result codes as OPEN.
1150 All images will be in GIF (Graphics Interchange Format). In the case of
1151 Citadel/UX, the server will convert the supplied filename to all lower case,
1152 append the characters ".gif" to the filename, and look for it in the "images"
1153 subdirectory. As with the MESG command, there are several "well known"
1154 images which are likely to exist on most servers:
1156 hello - "Welcome" graphics to be displayed alongside MESG "hello"
1157 goodbye - Logoff banner graphics to be displayed alongside MESG "goodbye"
1158 background - Background image (usually tiled) for graphical clients
1160 The following "special" image names are defined in Citadel/UX server version
1163 _userpic_ - Picture of a user (send the username as the second argument)
1164 _floorpic_ - A graphical floor label (send the floor number as the second
1165 argument). Clients which request a floor picture will display
1166 the picture *instead* of the floor name.
1167 _roompic_ - A graphic associated with the *current* room. Clients which
1168 request a room picture will display the picture in *addition*
1169 to the room name (i.e. it's used for a room banner, as
1170 opposed to the floor picture's use in a floor listing).
1173 NETP (authenticate as network session with system NET Password)
1175 This command is used by client software to identify itself as a transport
1176 session for IGnet/Open BBS to BBS networking. It should be called with
1177 two arguments: the node name of the calling system, and the system net
1178 password for the server. If the authentication succeeds, NETP will return
1179 OK, otherwise, it returns ERROR.
1182 NUOP (Network Upload OPen file)
1184 Open a network spool file for uploading. The client must have already
1185 identified itself as a network session using the NETP command. If the command
1186 returns OK, the client may begin transmitting IGnet/Open spool data using
1187 a series of WRIT commands. When a UCLS command is issued, the spooled data
1188 is entered into the BBS if the argument to UCLS is 1 or discarded if the
1189 argument to UCLS is 0. If the client has not authenticated itself with a
1190 NETP command, ERROR+HIGHER_ACCESS_REQUIRED will be returned.
1193 NDOP (Network Download OPen file)
1195 Open a network spool file for downloading. The client must have already
1196 identified itself as a network session using the NETP command. If the command
1197 returns OK, the client may begin receiving IGnet/Open spool data using
1198 a series of READ commands. When a CLOS command is issued, the spooled data
1199 is deleted from the server and may not be read again. If the client has not
1200 authenticated itself with a NETP command, ERROR+HIGHER_ACCESS_REQUIRED will
1204 LFLR (List all known FLooRs)
1206 On systems supporting floors, this command lists all known floors. The
1207 command accepts no parameters. It will return ERROR+NOT_LOGGED_IN if no
1208 user is logged in. Otherwise it returns LISTING_FOLLOWS and a list of
1209 the available floors, each line consisting of three fields:
1211 1. The floor number associated with the floor
1212 2. The name of the floor
1213 3. Reference count (number of rooms on this floor)
1216 CFLR (Create a new FLooR)
1218 This command is used to create a new floor. It should be passed two
1219 arguments: the name of the new floor to be created, and a 1 or 0 depending
1220 on whether the client is actually creating a floor or merely checking to
1221 see if it has permission to create the floor. The user must be logged in
1222 and have Aide privileges to create a floor.
1224 If the command succeeds, it will return OK followed by the floor number
1225 associated with the new floor. Otherwise, it will return ERROR (plus perhaps
1226 HIGHER_ACCESS_REQUIRED, ALREADY_EXISTS, or INVALID_FLOOR_OPERATION)
1227 followed by a description of why the command failed.
1232 This command is used to delete a floor. It should be passed two
1233 argument: the *number* of the floor to be deleted, and a 1 or 0 depending
1234 on whether the client is actually deleting the floor or merely checking to
1235 see if it has permission to delete the floor. The user must be logged in
1236 and have Aide privileges to delete a floor.
1238 Floors that contain rooms may not be deleted. If there are rooms on a floor,
1239 they must be either deleted or moved to different floors first. This implies
1240 that the Main Floor (floor 0) can never be deleted, since Lobby>, Mail>, and
1241 Aide> all reside on the Main Floor and cannot be deleted.
1243 If the command succeeds, it will return OK. Otherwise it will return
1244 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1245 followed by a description of why the command failed.
1250 Edit the parameters of a floor. The client may pass one or more parameters
1253 1. The number of the floor to be edited
1254 2. The desired new name
1256 More parameters may be added in the future. Any parameters not passed to
1257 the server will remain unchanged. A minimal command would be EFLR and a
1258 floor number -- which would do nothing. EFLR plus the floor number plus a
1259 floor name would change the floor's name.
1261 If the command succeeds, it will return OK. Otherwise it will return
1262 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1265 IDEN (IDENtify the client software)
1267 The client software has the option to identify itself to the server.
1268 Currently, the server does nothing with this information except to write
1269 it to the syslog to satisfy the system administrator's curiosity. Other
1270 uses might become apparent in the future.
1272 The IDEN command should contain five fields: a developer ID number (same as
1273 the server developer ID numbers in the INFO command -- please obtain one if
1274 you are a new developer), a client ID number (which does not have to be
1275 globally unique - only unique within the domain of the developer number),
1276 a version number, a free-form text string describing the client, and the name
1277 of the host the user is located at.
1279 It is up to the server to determine whether to accept the host name or to
1280 use the host name it has detected itself. Generally, if the client is
1281 running on a trusted host (either localhost or a well-known publically
1282 accessible client) it should use the host name transmitted by IDEN,
1283 otherwise it should use the host name it has detected itself.
1285 IDEN always returns OK, but since that's the only way it ever returns
1286 there's no point in checking the result code.
1289 IPGM (identify as an Internal ProGraM)
1291 IPGM is a low-level command that should not be used by normal user clients.
1292 It is used for various utilities to communicate with the server on the same
1293 host. For example, the networker (netproc.c) logs onto the server as an
1294 internal program in order to fetch and store messages. Since user clients
1295 do not utilize this command (or any of its companion commands), developers
1296 writing Citadel-compatible servers need not implement it.
1298 The sole argument to IPGM is the system's internal program password. This
1299 password is generated by the setup program and stored in the config file.
1300 Since internal programs have access to the config file, they know the correct
1303 IPGM returns OK for a correct authentication or ERROR otherwise.
1306 CHAT (enter CHAT mode)
1308 This command functions differently from every other command in the system. It
1309 is used to implement multi-user chat. For this to function, a new transfer
1310 mode, called START_CHAT_MODE, is implemented. If a client does not support
1311 chat mode, it should never send a CHAT command!
1313 In chat mode, messages may arrive asynchronously from the server at any
1314 time. The client may send messages at any time. This allows the arrival of
1315 messages without the client having to poll for them. Arriving messages will
1316 be of the form "user|message", where the "user" portion is, of course, the
1317 name of the user sending the message, and "message" is the message text.
1319 Chat mode ends when the server says it ends. The server will signal the end
1320 of chat mode by transmitting "000" on a line by itself. When the client reads
1321 this line, it must immediately exit from chat mode without sending any
1322 further traffic to the server. The next transmission sent to the server
1323 will be a regular server command.
1325 The Citadel/UX server understands the following commands:
1326 /quit - Exit from chat mode (causes the server to do an 000 end)
1327 /who - List users currently in chat
1328 /whobbs - List users currently in chat and on the bbs
1329 /me - Do an irc-style action.
1330 /join - Join a new "room" in which all messages are only heard by
1331 people in that room.
1332 /msg - /msg <user> <msg> will send the msg to <user> only.
1333 /help - Print help information
1334 NOOP - Do nothing (silently)
1336 Any other non-empty string is treated as message text and will be broadcast
1337 to other users currently in chat.
1340 SEXP (Send EXPress messages)
1342 This is one of two commands which implement "express messages" (also known
1343 as "paging"). An express message is a near-real-time message sent from one
1344 logged in user to another. When an express message is sent, it will be
1345 displayed the next time the target user executes a PEXP or GEXP command.
1347 The SEXP command accepts two arguments: the name of the user to send the
1348 message to, and the text of the message. If the message is successfully
1349 transmitted, OK is returned. If the target user is not logged in or if
1350 anything else goes wrong, ERROR is returned.
1352 If the server supports extended paging, sending a zero-length message
1353 merely checks for the presence of the requested user without actually sending
1354 a message. Sending a message consisting solely of a "-" (hyphen) will cause
1355 the server to return SEND_LISTING if the requested user is logged in, and the
1356 client can then transmit a multi-line page.
1358 The reserved name "broadcast" may be used instead of a user name, to
1359 broadcast an express message to all users currently connected to the server.
1361 Do be aware that if an express message is transmitted to a user who is logged
1362 in using a client that does not check for express messages, the message will
1366 PEXP (Print EXPress messages) ***DEPRECATED***
1368 This command is deprecated; it will eventually disappear from the protocol and
1369 its use is not recommended. Please use the GEXP command instead.
1371 Called without any arguments, PEXP simply dumps out the contents
1372 of any waiting express messages. It returns ERROR if there is a problem,
1373 otherwise it returns LISTING_FOLLOWS followed by all messages.
1375 So how does the client know there are express messages waiting? It could
1376 execute a random PEXP every now and then. Or, it can check the byte in
1377 server return code messages, between the return code and the parameters. In
1378 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1379 an "*" in this position to signify the presence of waiting express messages.
1382 EBIO (Enter BIOgraphy)
1384 Transmit to the server a free-form text file containing a little bit of
1385 information about the user for other users to browse. This is typically
1386 referred to as a 'bio' online. EBIO returns SEND_LISTING if it succeeds,
1387 after which the client is expected to transmit the file, or any of the usual
1388 ERROR codes if it fails.
1391 RBIO (Read BIOgraphy)
1393 Receive from the server a named user's bio. This command should be passed
1394 a single argument - the name of the user whose bio is requested. RBIO returns
1395 LISTING_FOLLOWS plus the bio file if the user exists and has a bio on file,
1396 ERROR+NO_SUCH_USER if the named user does not exist, or ERROR+FILE_NOT_FOUND
1397 if the user exists but has no bio on file.
1400 STEL (enter STEaLth mode)
1402 When in "stealth mode," a user will not show up in the "Who is online"
1403 listing (the RWHO server command). Only Aides may use stealth mode. The
1404 STEL command accepts one argument: a 1 indicating that the user wishes to
1405 enter stealth mode, or a 0 indicating that the user wishes to exit stealth
1406 mode. STEL returns OK if the command succeeded, ERROR+NOT_LOGGED_IN if no
1407 user is logged in, or ERROR+HIGHER_ACCESS_REQUIRED if the user is not an Aide.
1409 The STEL command also makes it so a user does not show up in the chat room
1413 LBIO (List users who have BIOs on file)
1415 This command is self-explanatory. Any user who has used EBIO to place a bio
1416 on file is listed. LBIO almost always returns LISTING_FOLLOWS followed by
1417 this listing, unless it experiences an internal error in which case ERROR
1421 MSG2 (read MeSsaGe, mode 2)
1423 MSG2 follows the same calling convention as MSG0. The difference between
1424 the two commands is that MSG2 outputs messages in standard RFC822 format
1425 rather than in Citadel/UX proprietary format.
1427 This command was implemented in order to make various gateway programs
1428 easier to implement, and to provide some sort of multimedia support in the
1429 future. Keep in mind that when this command is used, all messages will be
1430 output in fixed 80-column format.
1433 MSG3 (read MeSsaGe, mode 3 -- internal command)
1435 MSG3 is for use by internal programs only and should not be utilized by
1436 user-mode clients. It does require IPGM authentication. MSG3 follows the
1437 same calling convention as the other MSG commands, but upon success returns
1438 BINARY_FOLLOWS followed by a data block containing the _raw_ message format
1442 ENT3 (ENTer message, mode 3 -- internal command)
1444 ENT3 is for use by internal programs only and should not be utilized by
1445 user-mode clients. It does require IPGM authentication. This command posts
1446 a raw message straight into the message base without modification or performing
1447 any checks. It accepts the following arguments:
1449 0 - Post flag. This should be set to 1 to post a message. If it is
1450 set to 0, the server only returns OK or ERROR (plus any flags describing
1451 the error) without reading in a message. This is used to verify the operation
1452 before actually transmitting a message.
1453 1 - Recipient. This argument is utilized only for private mail messages.
1454 It is ignored for public messages. It contains, of course, the name of the
1455 recipient of the message.
1456 2 - The size (in bytes) of the message to be transmitted.
1458 ENT3 returns OK to tell the client that a message can be posted, ERROR if
1459 there would be a problem with the operation, or SEND_BINARY followed by a byte
1460 count if it is expecting the message to be transmitted.
1463 TERM (TERMinate another session)
1465 In a multithreaded environment, it sometimes becomes necessary to terminate
1466 a session that is unusable for whatever reason. The TERM command performs
1467 this task. Naturally, only Aides can execute TERM. The command should be
1468 called with a single argument: the session ID (obtained from an RWHO command)
1469 of the session to be terminated.
1471 TERM returns OK if the session was terminated, or ERROR otherwise. Note that
1472 a client program is prohibited from terminating the session it is currently
1476 NSET (Network SETup commands)
1478 Aides may use this command to configure the networker. This command's
1479 parameters are passed directly to the 'netsetup' command line utility. If
1480 netsetup returns a non-zero exit code, ERROR is returned, along with the
1481 error message (if any). If netsetup returns a zero (success) exit code,
1482 LISTING_FOLLOWS is returned, followed by zero or more lines of output (since
1483 netsetup may have information to display, such as a room or node list) and
1484 the usual '000' listing terminator.
1487 DOWN (shut DOWN the server)
1489 This command, which may only be executed by an Aide, immediately shuts down
1490 the server. It is only implemented on servers on which such an operation is
1491 possible, such as a multithreaded Citadel engine. The server does not restart.
1492 DOWN returns OK if the user is allowed to shut down the server, in which case
1493 the client program should expect the connection to be immediately broken.
1496 SCDN (Schedule or Cancel a shutDowN)
1498 SCDN sets or clears the "scheduled shutdown" flag. Pass this command a 1 or
1499 0 to respectively set or clear the flag. When the "scheduled shutdown" flag is
1500 set, the server will be shut down when there are no longer any users logged in.
1501 Any value other than 0 or 1 will not change the flag, only report its state.
1502 No users will be kicked off the system, and in fact the server is still available
1503 for new connections. The command returns ERROR if it fails; otherwise, it
1504 returns OK followed by a number representing the current state of the flag.
1507 EMSG (Enter a system MeSsaGe)
1509 This is the opposite of the MESG command - it allows the creation and editing
1510 of system messages. The only argument passed to EMSG is the name of the
1511 file being transmitted. If the file exists in any system message directory
1512 on the server it will be overwritten, otherwise a new file is created. EMSG
1513 returns SEND_LISTING on success or ERROR+HIGHER_ACCESS_REQUIRED if the user
1516 Typical client software would use MESG to retrieve any existing message into
1517 an edit buffer, then present an editor to the user and run EMSG if the changes
1521 UIMG (Upload an IMaGe file)
1523 UIMG is complemenary to OIMG; it is used to upload an image to the server.
1524 The first parameter supplied to UIMG should be 0 if the client is only checking
1525 for permission to upload, or 1 if the client is actually attempting to begin
1526 the upload operation. The second argument is the name of the file to be
1527 transmitted. In Citadel/UX, the filename is converted to all lower case,
1528 appended with the characters ".gif", and stored in the "images" directory.
1530 UIMG returns OK if the client has permission to perform the requested upload,
1531 or ERROR+HIGHER_ACCESS_REQUIRED otherwise. If the client requested to begin
1532 the operation (first parameter set to 1), an upload file is opened, and the
1533 client should begin writing to it with WRIT commands, then close it with a
1536 The supplied filename should be one of:
1538 -> _userpic_ (Server will attempt to write to the user's online photo)
1539 -> Any of the "well known" filenames described in the writeup for the
1542 ----------------------------------------------
1543 The following are for citserver 5.02 and above
1544 ----------------------------------------------
1546 HCHG (Hostname CHanGe)
1548 HCHG is a command, usable by any user, that allows a user to change their RWHO
1549 host value. This will mask a client's originating hostname from normal
1550 users; access level 6 and higher see an entry right underneath the spoofed
1551 entry listing the actual hostname the user originates from.
1553 The format of an HCHG command is:
1557 If a HCHG command is successful, the value OK (200) is returned.
1560 RCHG (Roomname CHanGe)
1562 RCHG is a command, usable by any user, that allows a user to change their RWHO
1563 room value. This will mask a client's roomname from normal users; access
1564 level 6 and higher see an entry right underneath the spoofed entry listing
1565 the actual room the user is in.
1567 The format of an RCHG command is:
1571 If a RCHG command is successful, the value OK (200) is returned.
1574 UCHG (Username CHanGe)
1576 UCHG is an aide-level command which allows an aide to effectively change their
1577 username. If this value is blank, the user goes into stealth mode (see
1579 will show up as being from the real username in this mode, however. In
1580 addition, the RWHO listing will include both the spoofed and real usernames.
1582 The format of an UCHG command is:
1586 If a UCHG command is successful, the value OK (200) is returned.
1589 TIME (get server local TIME)
1591 TIME returns OK followed by the current time measured in seconds since
1592 00:00:00 GMT, Jan 1, 1970 (standard Unix format).
1594 This is used in allowing a client to calculate idle times.
1597 AGUP (Administrative Get User Parameters)
1598 ASUP (Administrative Set User Parameters)
1600 These commands are only executable by Aides and by server extensions running
1601 at system-level. They are used to get/set any and all parameters relating to
1602 a user account. AGUP requires only one argument: the name of the user in
1603 question. SGUP requires all of the parameters to be set. The parameters are
1604 as follows, and are common to both commands:
1608 2 - Flags (see citadel.h)
1613 7 - Timestamp of last call
1614 8 - Purge time (in days) for this user (or 0 to use system default)
1616 Upon success, AGUP returns OK followed by all these parameters, and ASUP
1617 simply returns OK. If the client has insufficient access to perform the
1618 requested operation, ERROR+HIGHER_ACCESS_REQUIRED is returned. If the
1619 requested user does not exist, ERROR+NO_SUCH_USER is returned.
1623 GPEX (Get Policy for message EXpiration)
1625 Returns the policy of the current room, floor, or site regarding the automatic
1626 purging (expiration) of messages. The following policies are available:
1627 0 - Fall back to the policy of the next higher level. If this is a room,
1628 use the floor's default policy. If this is a floor, use the system
1629 default policy. This is an invalid value for the system policy.
1630 1 - Do not purge messages automatically.
1631 2 - Purge by message count. (Requires a value: number of messages)
1632 3 - Purge by message age. (Requires a value: number of days)
1634 The format of this command is: GPEX <which>
1635 The value of <which> must be one of: "room" "floor" "site"
1637 If successful, GPEX returns OK followed by <policy>|<value>.
1641 SPEX (Set Polict for message EXpiration)
1643 Sets the policy of the current room, floor, or site regarding the automatic
1644 purging (expiration) of messages. See the writeup for the GPEX command for
1645 the list of available policies.
1647 The format of this command is: SPEX <which>|<policy>|<value>
1648 The value of <which> must be one of: "room" "floor" "site"
1650 If successful, GPEX returns OK; otherwise, an ERROR code is returned.
1654 CONF (get or set global CONFiguration options)
1656 Retrieves or sets various system-wide configuration and policy options. This
1657 command is only available to Aides. The sole parameter accepted is a command,
1658 which should be either GET or SET. If the GET command succeeds, CONF will
1659 return LISTING_FOLLOWS followed by the fields described below, one line at a
1660 time. If the SET command succeeds, CONF will return SEND_LISTING and expect
1661 the fields described below, one line at a time (don't worry about other fields
1662 being added in the future; if a 'short' configuration list is sent, the missing
1663 values at the end will be left unchanged on the system). If either command
1664 fails for any reason, ERROR is returned.
1666 The configuration lines are as follows:
1669 2. Fully qualified domain name
1670 3. Human-readable node name
1671 4. Landline telephone number of this system
1672 5. Flag (0 or 1) - creator of private room automatically becomes room aide
1673 6. Server connection idle timeout (in seconds)
1674 7. Initial access level for new users
1675 8. Flag (0 or 1) - require registration for new users
1676 9. Flag (0 or 1) - automatically move Problem User messages to twit room
1677 10. Name of twit room
1678 11. Text of <more> prompt
1679 12. Flag (0 or 1) - restrict access to Internet mail
1680 13. Geographic location of this system
1681 14. Name of the system administrator
1682 15. Number of maximum concurrent sessions allowed on the server
1683 16. Password for server-to-server networking
1684 17. Default purge time (in days) for users
1685 18. Default purge time (in days) for rooms
1686 19. Name of room to log express messages to (or a zero-length name for none)
1687 20. Access level required to create rooms
1688 21. Maximum message length which may be entered into the system
1692 EXPI (EXPIre system objects)
1694 Begins purge operations for objects which, according to site policy, are
1695 "old" and should be removed. EXPI should be called with one argument, one of:
1697 "messages" (purge old messages out of each room)
1698 "users" (purge old users from the userlog)
1699 "rooms" (remove rooms which have not been posted in for some time)
1700 "visits" (purge dereferenced user/room relationship records)
1702 EXPI returns OK (probably after a long delay while it does its work) if it
1703 succeeds; otherwise it returns an ERROR code.
1705 This command is probably temporary, until we can work some sort of scheduler
1706 into the system. It is implemented in the serv_expire module.
1710 MSG4 (read MeSsaGe, mode 4 -- enumerate MIME parts)
1712 FIX ... do the writeup for this once it's done.
1716 OPNA (OPeN Attachment)
1718 Opens, as a download file, a component of a MIME-encoded message. The two
1719 parameters which must be passed to this command are the message number and the
1720 name of the desired section. If the message or section does not exist, an
1721 appropriate ERROR code will be returned; otherwise, if the open is successful,
1722 this command will succeed returning the same information as an OPEN command.
1725 GEXP (Get EXPress messages)
1727 This is a more sophisticated way of retrieving express messages than the old
1728 PEXP method. If there are no express messages waiting, PEXP returns ERROR;
1729 otherwise, it returns LISTING_FOLLOWS and the following arguments:
1731 0 - a boolean value telling the client whether there are any additional
1732 express messages waiting following this one
1733 1 - a Unix-style timestamp
1734 2 - flags (see server.h for more info)
1735 3 - the name of the sender
1736 4 - the node this message originated on (for future support of PIP, ICQ, etc.)
1738 The text sent to the client will be the body of the express message.
1740 So how does the client know there are express messages waiting? It could
1741 execute a random GEXP every now and then. Or, it can check the byte in
1742 server return code messages, between the return code and the parameters. In
1743 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1744 an "*" in this position to signify the presence of waiting express messages.
1748 CICQ (Citadel ICQ metaclient setup)
1751 This command is most likely a temporary one. Citadel will eventually have
1752 more robust functionality for abstract configuration screens, and when that
1753 happens, this command will certainly be migrated there. If you're developing
1754 a client, don't spend a lot of time working on ICQ screens.
1756 If a Citadel server has the ICQ Metaclient installed, this command is used
1757 to configure it. It has several usages:
1761 This tells Citadel the user's ICQ uin (second argument) and password (third
1762 argument). When called in this fashion, CICQ will return either OK or ERROR.
1763 It should be noted, however, that the only way an ERROR code can be returned
1764 is if the uin and/or password is not supplied. Authentication failures cannot
1765 be immediately detected, because the ICQ protocol is asynchronous.
1769 Request the current contact list. If successful, CICQ will return
1770 LISTING_FOLLOWS followed by zero or more contacts in the format
1776 Upload a new contact list. If successful, CICQ will return SEND_LISTING
1777 after which the client should transmit zero or more uin's, one per line. The
1778 server will then attempt to contact the ICQ server to determine nicknames
1783 Always returns OK followed by a 1 (connected to ICQ) or 0 (not connected).