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 <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 the methodology employed by Citadel/UX.
35 Citadel/UX offers Citadel BBS service using TCP/IP. It does so via a
36 multithreaded server listening on a TCP port. Older (4.xx) versions employed
37 an inetd-based server.
39 The port number officially assigned to Citadel by the IANA is TCP/504. Since
40 our session layer assumes a clean, reliable, sequenced connection, the use
41 of UDP would render the server unstable and unusable, so we stick with TCP.
44 GENERAL INFORMATION ABOUT THE SERVER
45 ------------------------------------
47 The server is connection-oriented and stateful: each client requires its own
48 connection to a server process, and when a command is sent, the client must
49 read the response, and then transfer data or change modes if necessary.
51 The session layer is very much like other Internet protocols such as SMTP
52 or NNTP. A client program sends one-line commands to the server, and the
53 server responds with a three-digit numeric result code followed by a message
54 describing what happened. This cycle continues until the end of the
57 Unlike protocols such as FTP, all data transfers occur in-band. This means
58 that the same connection that is used for exchange of client/server
59 messages, will also be used to transfer data back and forth. (FTP opens a
60 separate connection for data transfers.) We do this to allow the server to
61 function over transports which can only handle one session at a time (such
62 as a dialup connection).
68 The server will respond to all commands with a 3-digit result code, which
69 will be the first three characters on the line. The rest of the line may
70 contain a human-readable string explaining what happened. (Some client
71 software will display some of these strings to the user.)
73 The first digit is the most important. The following codes are defined for
74 this position: ERROR, OK, MORE_DATA, LISTING_FOLLOWS, and SEND_LISTING.
76 The second and third digits may provide a reason as to why a command
77 succeeded or failed. See ipcdef.h for the available codes.
79 ERROR means the command did not complete.
80 OK means the command executed successfully.
81 MORE_DATA means the command executed partially. Usually this means that
82 another command needs to be executed to complete the operation. For example,
83 sending the USER command to log in a user usually results in a MORE_DATA
84 result code, because the client needs to execute a PASS command to send the
85 password and complete the login.
86 LISTING_FOLLOWS means that after the server response, the server will
87 output a listing of some sort. The client *must* read the listing, whether
88 it wants to or not. The end of the listing is signified by the string
89 "000" on a line by itself.
90 SEND_LISTING is the opposite of LISTING_FOLLOWS. It means that the client
91 should begin sending a listing of some sort. The client *must* send something,
92 even if it is an empty listing. Again, the listing ends with "000" on a line
99 Zero or more parameters may be passed to a command. When more than one
100 parameter is passed to a command, they should be separated by the "|"
103 In this example, we're using the "SETU" command and passing three
104 parameters: 80, 24, and 260.
106 When the server spits out data that has parameters, if more than one
107 parameter is returned, they will be separated by the "|" symbol like
110 In this example, we just executed the "GETU" command, and it returned us
111 an OK result code (the '2' in the 200) and three parameters: 80, 24, and
118 This is a listing of all the commands that a Citadel/UX server can execute.
123 This command does nothing. It takes no arguments and always returns
124 OK. It is intended primarily for testing and development, but it might also
125 be used as a "keep alive" command to prevent the server from timing out, if
126 it's running over a transport that needs this type of thing.
129 ECHO (ECHO something)
131 This command also does nothing. It simply returns OK followed by whatever
137 Terminate the server connection. This command takes no arguments. It
138 returns OK and closes the connection immediately.
143 Log out the user without closing the server connection. It always returns
144 OK even if no user is logged in.
147 USER (send USER name)
149 The first step in logging in a user. This command takes one argument: the
150 name of the user to be logged in. If the user exists, a MORE_DATA return
151 code will be sent, which means the client should execute PASS as the next
152 command. If the user does not exist, ERROR is returned.
157 The second step in logging in a user. This command takes one argument: the
158 password for the user we are attempting to log in. If the password doesn't
159 match the correct password for the user we specified for the USER command,
160 or if a USER command has not been executed yet, ERROR is returned. If the
161 password is correct, OK is returned and the user is now logged in... and
162 most of the other server commands can now be executed. Along with OK, the
163 following parameters are returned:
165 0 - The user's name (in case the client wants the right upper/lower casing)
166 1 - The user's current access level
169 4 - Various flags (see citadel.h)
173 NEWU (create NEW User account)
175 This command creates a new user account and logs it in. The argument to
176 this command will be the name of the account. No case conversion is done
177 on the name. Note that the new account is installed with a default
178 configuration, and no password, so the client should immediately prompt the
179 user for a password and install it with the SETP command as soon as this
180 command completes. This command returns OK if the account was created and
181 logged in, or ERROR if another user already exists with this name. If OK,
182 it will also return the same parameters that PASS returns.
185 SETP (SET new Password)
187 This command sets a new password for the currently logged in user. The
188 argument to this command will be the new password. The command always
189 returns OK, unless the client is not logged in, in which case it will return
193 LKRN (List Known Rooms with New messages)
195 List known rooms with new messages. If the client is not logged in, ERROR
196 is returned. Otherwise, LISTING_FOLLOWS is returned, followed by the room
197 listing. Each line in the listing contains the full name of a room, followed
198 by the '|' symbol, and then a number that may contain the following bits:
201 #define QR_PERMANENT 1 /* Room does not purge */
202 #define QR_PRIVATE 4 /* Set for any type of private room */
203 #define QR_PASSWORDED 8 /* Set if there's a password too */
204 #define QR_GUESSNAME 16 /* Set if it's a guessname room */
205 #define QR_DIRECTORY 32 /* Directory room */
206 #define QR_UPLOAD 64 /* Allowed to upload */
207 #define QR_DOWNLOAD 128 /* Allowed to download */
208 #define QR_VISDIR 256 /* Visible directory */
209 #define QR_ANONONLY 512 /* Anonymous-Only room */
210 #define QR_ANON2 1024 /* Anonymous-Option room */
211 #define QR_NETWORK 2048 /* Shared network room */
212 #define QR_PREFONLY 4096 /* Preferred status needed to enter */
213 #define QR_READONLY 8192 /* Aide status required to post */
216 Other bits may be defined in the future. The listing terminates, as with
217 all listings, with "000" on a line by itself.
219 Starting with version 4.01 and above, floors are supported. The first
220 argument to LKRN should be the number of the floor to list rooms from. Only
221 rooms from this floor will be listed. If no arguments are passed to LKRN, or
222 if the floor number requested is (-1), rooms on all floors will be listed.
224 The third field displayed on each line is the number of the floor the room
225 is on. The LFLR command should be used to associate floor numbers with
228 The fourth field displayed on each line is a "room listing order." Unless
229 there is a compelling reason not to, clients should sort any received room
230 listings by this value.
234 LKRO (List Known Rooms with Old [no new] messages)
236 This follows the same usage and format as LKRN.
239 LZRM (List Zapped RooMs)
241 This follows the same usage and format as LKRN and LKRO.
244 LKRA (List All Known Rooms)
246 Same format. Lists all known rooms, with or without new messages.
249 LRMS (List all accessible RooMS)
251 Again, same format. This command lists all accessible rooms, known and
252 forgotten, with and without new messages. It does not, however, list
253 inaccessible private rooms.
256 GETU (GET User configuration)
258 This command retrieves the screen dimensions and user options for the
259 currently logged in account. ERROR will be returned if no user is logged
260 in, of course. Otherwise, OK will be returned, followed by three parameters.
261 The first parameter is the user's screen width, the second parameter is the
262 user's screen height, and the third parameter is a bag of bits with the
265 #define US_LASTOLD 16 /* Print last old message with new */
266 #define US_EXPERT 32 /* Experienced user */
267 #define US_UNLISTED 64 /* Unlisted userlog entry */
268 #define US_NOPROMPT 128 /* Don't prompt after each message */
269 #define US_DISAPPEAR 512 /* Use "disappearing msg prompts" */
270 #define US_PAGINATOR 2048 /* Pause after each screen of text */
272 There are other bits, too, but they can't be changed by the user (see below).
275 SETU (SET User configuration)
277 This command does the opposite of SETU: it takes the screen dimensions and
278 user options (which were probably obtained with a GETU command, and perhaps
279 modified by the user) and writes them to the user account. This command
280 should be passed three parameters: the screen width, the screen height, and
281 the option bits (see above).
283 Note that there exist bits here which are not listed in this document. Some
284 are flags that can only be set by Aides or the system administrator. SETU
285 will ignore attempts to toggle these bits. There also may be more user
286 settable bits added at a later date. To maintain later downward compatibility,
287 the following procedure is suggested:
289 1. Execute GETU to read the current flags
290 2. Toggle the bits that we know we can toggle
291 3. Execute SETU to write the flags
293 If we are passed a bit whose meaning we don't know, it's best to leave it
294 alone, and pass it right back to the server. That way we can use an old
295 client on a server that uses an unknown bit without accidentally clearing
296 it every time we set the user's configuration.
301 This command is used to goto a new room. When the user first logs in (login
302 is completed after execution of the PASS command) this command is
303 automatically and silently executed to take the user to the first room in the
304 system (usually called the Lobby).
306 This command can be passed one or two parameters. The first parameter is,
307 of course, the name of the room. Although it is not case sensitive, the
308 full name of the room must be used. Wildcard matching or unique string
309 matching of room names should be the responsibility of the client.
311 Note that the reserved room name "_BASEROOM_" can be passed to the server
312 to cause the goto command to take the user to the first room in the system,
313 traditionally known as the Lobby>. As long as a user is logged in, a
314 GOTO command to _BASEROOM_ is guaranteed to succeed. This is useful to
315 allow client software to return to the base room when it doesn't know
318 There are also two additional reserved room names:
319 "_MAIL_" translates to the system's designated room for e-mail messages.
320 "_BITBUCKET_" goes to whatever room has been chosen for messages
323 The second (and optional) parameter is a password, if one is required for
324 access to the room. This allows for all types of rooms to be accessed via
325 this command: for public rooms, invitation-only rooms to which the user
326 has access, and preferred users only rooms to which the user has access, the
327 room will appear in a room listing. For guess-name rooms, this command
328 will work transparently, adding the room to the user's known room list when
329 it completes. For passworded rooms, access will be denied if the password
330 is not supplied or is incorrect, or the command will complete successfully
331 if the password is correct.
333 The possible result codes are:
335 OK - The command completed successfully. User is now in the room.
336 (See the list of returned parameters below)
338 ERROR - The command did not complete successfully. Check the second and
339 third positions of the result code to find out what happened:
341 NOT_LOGGED_IN - Of course you can't go there. You didn't log in.
342 PASSWORD_REQUIRED - Either a password was not supplied, or the supplied
343 password was incorrect.
344 NO_SUCH_ROOM - The requested room does not exist.
346 The typical procedure for entering a passworded room would be:
348 1. Execute a GOTO command without supplying any password.
349 2. ERROR+PASSWORD_REQUIRED will be returned. The client now knows that
350 the room is passworded, and prompts the user for a password.
351 3. Execute a GOTO command, supplying both the room name and the password.
352 4. If OK is returned, the command is complete. If, however,
353 ERROR+PASSWORD_REQUIRED is still returned, tell the user that the supplied
354 password was incorrect. The user remains in the room he/she was previously
357 When the command succeeds, these parameters are returned:
358 0. The name of the room
359 1. Number of unread messages in this room
360 2. Total number of messages in this room
361 3. Info flag: set to nonzero if the user needs to read this room's info
362 file (see RINF command below)
363 4. Various flags associated with this room. (See LKRN cmd above)
364 5. The highest message number present in this room
365 6. The highest message number the user has read in this room
366 7. Boolean flag: 1 if this is a Mail> room, 0 otherwise.
367 8. Aide flag: 1 if the user is either the Room Aide for this room, *or* is
368 a regular Aide (this makes access checks easy).
369 9. The number of new Mail messages the user has (useful for alerting the
370 user to the arrival of new mail during a session)
371 10. The floor number this room resides on
374 MSGS (get pointers to MeSsaGeS in this room)
376 This command obtains a listing of all the messages in the current room
377 which the client may request. This command may be passed a single parameter:
378 either "all", "old", or "new" to request all messages, only old messages, or
379 new messages. Or it may be passed two parameters: "last" plus a number, in
380 which case that many message pointers will be returned, or "first" plus a
381 number, for the corresponding effect. If no parameters are specified, "all"
384 In Citadel/UX 5.00 and above, the client may also specify "gt" plus a number,
385 to list all messages in the current room with a message number greater than
388 The third argument, valid only in Citadel/UX 5.60 and above, may be either
389 0 or 1. If it is 1, this command behaves differently: before a listing is
390 returned, the client must transmit a list of fields to search for. The field
391 headers are listed below in the writeup for the "MSG0" command.
393 This command can return three possible results. An ERROR code may be returned
394 if no user is currently logged in or if something else went wrong. Otherwise,
395 LISTING_FOLLOWS will be returned, and the listing will consist of zero or
396 more message numbers, one per line. The listing ends, as always, with the
397 string "000" alone on a line by itself. The listed message numbers can be used
398 to request messages from the system. If "search mode" is being used, the
399 server will return START_CHAT_MODE, and the client is expected to transmit
400 the search criteria, and then read the message list.
402 Since this is somewhat complex, here are some examples:
404 Example 1: Read all new messages
407 Server: 100 Message list...
413 Example 2: Read the last five messages
416 Server: 100 Message list...
424 Example 3: Read all messages written by "IGnatius T Foobar"
427 Server: 800 Send template then receive message list
428 Client: from|IGnatius T Foobar
442 Note that in "search mode" the client may specify any number of search
443 criteria. These criteria are applied with an AND logic.
447 MSG0 (read MeSsaGe, mode 0)
449 This is a command used to read the text of a message. "Mode 0" implies that
450 other MSG commands (MSG1, MSG2, etc.) will probably be added later on to read
451 messages in more robust formats. This command should be passed two arguments.
452 The first is the message number of the message being requested. In server
453 version 4.04 and above, the second argument may be set to either 0 to read the
454 entire message, or 1 to read the headers only.
456 The server should, of course, make sure that the client actually has access
457 to the message being requested before honoring this request. Citadel/UX does
458 so by checking the message number against the contents of the current room. If
459 it's not there, the request is denied.
461 If the request is denied, an ERROR code will be returned. Otherwise, the
462 LISTING_FOLLOWS code will be returned, followed by the contents of the message.
463 The following fields may be sent:
465 type= Formatting type. The currently defined types are:
466 0 = "traditional" Citadel formatting. This means that newlines should be
467 treated as spaces UNLESS the first character on the next line is a space. In
468 other words, only indented lines should generate a newline on the user's screen
469 when the message is being displayed. This allows a message to be formatted to
470 the reader's screen width. It also allows the use of proportional fonts.
471 1 = a simple fixed-format message. The message should be displayed to
472 the user's screen as is, preferably in a fixed-width font that will fit 80
474 4 = MIME format message. The message text is expected to contain a header
475 with the "Content-type:" directive (and possibly others).
477 msgn= The message ID of this message on the system it originated on.
478 path= An e-mailable path back to the user who wrote the message.
480 time= The date and time of the message, in Unix format (the number of
481 seconds since midnight on January 1, 1970, GMT).
483 from= The name of the author of the message.
484 rcpt= If the message is a private e-mail, this is the recipient.
485 room= The name of the room the message originated in.
486 node= The short node name of the system this message originated on.
487 hnod= The long node name of the system this message originated on.
488 zaps= The id/node of a message which this one zaps (supersedes).
490 text Note that there is no "=" after the word "text". This string
491 signifies that the message text begins on the next line.
494 WHOK (WHO Knows room)
496 This command is available only to Aides. ERROR+HIGHER_ACCESS_REQUIRED will
497 be returned if the user is not an Aide. Otherwise, it returns
498 LISTING_FOLLOWS and then lists, one user per line, every user who has
499 access to the current room.
502 INFO (get server INFO)
504 This command will *always* return LISTING_FOLLOWS and then print out a
505 listing of zero or more strings. Client software should be written to expect
506 anywhere from a null listing to an infinite number of lines, to allow later
507 backward compatibility. The current implementation defines the following
508 parts of the listing:
510 Line 1 - Your unique session ID on the server
511 Line 2 - The node name of the server BBS
512 Line 3 - Human-readable node name of the server BBS
513 Line 4 - The fully-qualified domain name (FQDN) of the server
514 Line 5 - The name of the server software, i.e. "Citadel/UX 4.00"
515 Line 6 - (The revision level of the server code) * 100
516 Line 7 - The geographical location of the BBS (city and state if in the US)
517 Line 8 - The name of the system administrator
518 Line 9 - A number identifying the server type (see below)
519 Line 10 - The text of the system's paginator prompt
520 Line 11 - Floor Flag. 1 if the system supports floors, 0 otherwise.
521 Line 12 - Paging level. 0 if the system only supports inline paging,
522 1 if the system supports "extended" paging (check-only and
523 multiline modes). See the SEXP command for further information.
525 *** NOTE! *** The "server type" code is intended to promote global
526 compatibility in a scenario in which developers have added proprietary
527 features to their servers or clients. We are attempting to avoid a future
528 situation in which users need to keep different client software around for
529 each BBS they use. *Please*, if you are a developer and plan to add
530 proprietary features:
532 -> Your client programs should still be able to utilize servers other than
534 -> Clients other than your own should still be able to utilize your server,
535 even if your proprietary extensions aren't supported.
536 -> Please contact Art Cancro <ajc@uncnsrd.mt-kisco.ny.us> and obtain a unique
537 server type code, which can be assigned to your server program.
538 -> If you document what you did in detail, perhaps it can be added to a
539 future release of the Citadel/UX program, so everyone can enjoy it. Better
540 yet, just work with the Citadel development team on the main source tree.
542 If everyone follows this scheme, we can avoid a chaotic situation with lots
543 of confusion about which client program works with which server, etc. Client
544 software can simply check the server type (and perhaps the revision level)
545 to determine ahead of time what commands may be utilized.
547 Please refer to "developers.txt" for information on what codes belong to whom.
551 RDIR (Read room DIRectory)
553 Use this command to read the directory of a directory room. ERROR+NOT_HERE
554 will be returned if the room has no directory, or some other error; ERROR +
555 HIGHER_ACCESS_REQUIRED will be returned if the room's directory is not
556 visible and the user does not have Aide or Room Aide privileges; otherwise
557 LISTING_FOLLOWS will be returned, followed by the room's directory. Each
558 line of the directory listing will contain three fields: a filename, the
559 length of the file, and a description.
561 The server message contained on the same line with LISTING_FOLLOWS will
562 contain the name of the system and the name of the directory, such as:
563 uncnsrd.mt-kisco.ny.us|/usr/bbs/files/my_room_directory
566 SLRP (Set Last-message-Read Pointer)
568 This command is used to mark messages as having been read. Its sole parameter
569 is the number of the last message that has been read. This allows the pointer
570 to be set at any arbitrary point in the room. Optionally, the parameter
571 "highest" may be used instead of a message number, to set the pointer to the
572 number of the highest message in the room, effectively marking all messages
573 in the room as having been read (ala the Citadel <G>oto command).
575 The command will return OK if the pointer was set, or ERROR if something
576 went wrong. If OK is returned, it will be followed by a single argument
577 containing the message number the last-read-pointer was set to.
580 INVT (INViTe a user to a room)
582 This command may only be executed by Aides, or by the room aide for the
583 current room. It is used primarily to add users to invitation-only rooms,
584 but it may also be used in other types of private rooms as well. Its sole
585 parameter is the name of the user to invite.
587 The command will return OK if the operation succeeded, or ERROR if it did
588 not. ERROR+HIGHER_ACCESS_REQUIRED may also be returned if the operation
589 would have been possible if the user had higher access, and ERROR+NOT_HERE
590 may be returned if the room is not a private room.
593 KICK (KICK a user out of a room)
595 This is the opposite of INVT: it is used to kick a user out of a private
596 room. It can also be used to kick a user out of a public room, but the
597 effect will only be the same as if the user <Z>apped the room - a non-stupid
598 user can simply un-zap the room to get back in.
601 GETR (GET Room attributes)
603 This command is used for editing the various attributes associated with a
604 room. A typical "edit room" command would work like this:
605 1. Use the GETR command to get the current attributes
606 2. Change some of them around
607 3. Use SETR (see below) to save the changes
608 4. Possibly also change the room aide using the GETA and SETA commands
610 GETR takes no arguments. It will only return OK if the SETR command will
611 also return OK. This allows client software to tell the user that he/she
612 can't edit the room *before* going through the trouble of actually doing the
613 editing. Possible return codes are:
615 ERROR+NOT_LOGGED_IN - No user is logged in.
616 ERROR+HIGHER_ACCESS_REQUIRED - Not enough access. Typically, only aides
617 and the room aide associated with the current room, can access this command.
618 ERROR+NOT_HERE - Lobby>, Mail>, and Aide> cannot be edited.
619 OK - Command succeeded. Parameters are returned.
621 If OK is returned, the following parameters will be returned as well:
623 0. The name of the room
624 1. The room's password (if it's a passworded room)
625 2. The name of the room's directory (if it's a directory room)
626 3. Various flags (bits) associated with the room (see LKRN cmd above)
627 4. The floor number on which the room resides
628 5. The room listing order
631 SETR (SET Room attributes)
633 This command sets various attributes associated with the current room. It
634 should be passed the following arguments:
636 0. The name of the room
637 1. The room's password (if it's a passworded room)
638 2. The name of the room's directory (if it's a directory room)
639 3. Various flags (bits) associated with the room (see LKRN cmd above)
640 4. "Bump" flag (see below)
641 5. The floor number on which the room should reside
642 6. The room listing order
644 *Important: You should always use GETR to retrieve the current attributes of
645 the room, then change what you want to change, and then use SETR to write it
646 all back. This is particularly important with respect to the flags: if a
647 particular bit is set, and you don't know what it means, LEAVE IT ALONE and
648 only toggle the bits you want to toggle. This will allow for upward
651 If the room is a private room, you have the option of causing all users who
652 currently have access, to forget the room. If you want to do this, set the
653 "bump" flag to 1, otherwise set it to 0.
658 This command is used to get the name of the Room Aide for the current room.
659 It will return ERROR+NOT_LOGGED_IN if no user is logged in, ERROR if there
660 is no current room, or OK if the command succeeded. Along with OK there will
661 be returned one parameter: the name of the Room Aide.
666 The opposite of GETA, used to set the Room Aide for the current room. One
667 parameter should be passed, which is the name of the user who is to be the
668 new Room Aide. Under Citadel/UX, this command may only be executed by Aides
669 and by the *current* Room Aide for the room. Return codes possible are:
670 ERROR+NOT_LOGGED_IN (Not logged in.)
671 ERROR+HIGHER_ACCESS_REQUIRED (Higher access required.)
672 ERROR+NOT_HERE (No current room, or room cannot be edited.
673 Under Citadel/UX, the Lobby> Mail> and Aide> rooms are non-editable.)
674 OK (Command succeeded.)
677 ENT0 (ENTer message, mode 0)
679 This command is used to enter messages into the system. It accepts four
682 0 - Post flag. This should be set to 1 to post a message. If it is
683 set to 0, the server only returns OK or ERROR (plus any flags describing
684 the error) without reading in a message. Client software should, in fact,
685 perform this operation at the beginning of an "enter message" command
686 *before* starting up its editor, so the user does not end up typing a message
687 in vain that will not be permitted to be saved. If it is set to 2, the
688 server will accept an "apparent" post name if the user is privileged enough.
689 This post name is arg 4.
690 1 - Recipient. This argument is utilized only for private mail messages.
691 It is ignored for public messages. It contains, of course, the name of the
692 recipient of the message.
693 2 - Anonymous flag. This argument is ignored unless the room allows
694 anonymous messages. In such rooms, this flag may be set to 1 to flag a
695 message as anonymous, otherwise 0 for a normal message.
696 3 - Format type. Any valid Citadel/UX format type may be used (this will
697 typically be 0; see the MSG0 command above).
698 4 - Post name. When postflag is 2, this is the name you are posting as.
699 This is an Aide only command.
701 Possible result codes:
702 OK - The request is valid. (Client did not set the "post" flag, so the
703 server will not read in message text.) If the message is an e-mail with
704 a recipient, the text that follows the OK code will contain the exact name
705 to which mail is being sent. The client can display this to the user. The
706 implication here is that the name that the server returns will contain the
707 correct upper and lower case characters. In addition, if the recipient is
708 having his/her mail forwarded, the forwarding address will be returned.
709 SEND_LISTING - The request is valid. The client should now transmit
710 the text of the message (ending with a 000 on a line by itself, as usual).
711 ERROR - Miscellaneous error. (Explanation probably follows.)
712 ERROR + NOT_LOGGED_IN - Not logged in.
713 ERROR + HIGHER_ACCESS_REQUIRED - Higher access is required. An
714 explanation follows, worded in a form that can be displayed to the user.
715 ERROR + NO_SUCH_USER - The specified recipient does not exist.
718 RINF (read Room INFormation file)
720 Each room has associated with it a text file containing a description of
721 the room, perhaps containing its intended purpose or other important
722 information. The info file for the Lobby> (the system's base room) is
723 often used as a repository for system bulletins and the like.
725 This command, which accepts no arguments, is simply used to read the info
726 file for the current room. It will return LISTING_FOLLOWS followed by
727 the text of the message (always in format type 0) if the request can be
728 honored, or ERROR if no info file exists for the current room (which is
729 often the case). Other error description codes may accompany this result.
731 When should this command be used? This is, of course, up to the discretion
732 of client software authors, but in Citadel it is executed in two situations:
733 the first time the user ever enters a room; and whenever the contents of the
734 file change. The latter can be determined from the result of a GOTO command,
735 which will tell the client whether the file needs to be read (see GOTO above).
738 DELE (DELEte a message)
740 Delete a message from the current room. The one argument that should be
741 passed to this command is the message number of the message to be deleted.
742 The return value will be OK if the message was deleted, or an ERROR code.
743 If the delete is successful, the message's reference count is decremented, and
744 if the reference count reaches zero, the message is removed from the message
748 MOVE (MOVE or copy a message to a different room)
750 Move a message to a different room. The two arguments that should be passed
751 to this command are the message number of the message to be deleted, and the
752 name of the target room. If the operation succeeds, the message will be
753 deleted from the current room and moved to the target room. An ERROR code
754 usually means that either the user does not have permission to perform this
755 operation, or that the target room does not exist.
757 In Citadel/UX 5.55 and above, a third argument may be specified: 0 or 1 to
758 designate whether the message should be moved (0) or copied (1) to the target
759 room. In the case of a "copy" operation, the message's reference count is
760 incremented, and a pointer to the message will exist in both the source *and*
761 target rooms. In the case of a "move" operation, the message pointer is
762 deleted from the source room and the reference count remains the same.
765 KILL (KILL current room)
767 This command deletes the current room. It accepts a single argument, which
768 should be nonzero to actually delete the room, or zero to merely check
769 whether the room can be deleted.
771 Once the room is deleted, the current room is undefined. It is suggested
772 that client software immediately GOTO another room (usually _BASEROOM_)
773 after this command completes.
775 Possible return codes:
777 OK - room has been deleted (or, if checking only, request is valid).
778 ERROR+NOT_LOGGED_IN - no user is logged in.
779 ERROR+HIGHER_ACCESS_REQUIRED - not enough access to delete rooms.
780 ERROR+NOT_HERE - this room can not be deleted.
783 CRE8 (CRE[ate] a new room)
785 This command is used to create a new room. Like some of the other
786 commands, it provides a mechanism to first check to see if a room can be
787 created before actually executing the command. CRE8 accepts the following
790 0 - Create flag. Set this to 1 to actually create the room. If it is
791 set to 0, the server merely checks that there is a free slot in which to
792 create a new room, and that the user has enough access to create a room. It
793 returns OK if the client should go ahead and prompt the user for more info,
794 or ERROR or ERROR+HIGHER_ACCESS_REQUIRED if the command will not succeed.
795 1 - Name for new room.
796 2 - Access type for new room:
798 1 - Private; can be entered by guessing the room's name
799 2 - Private; can be entered by knowing the name *and* password
800 3 - Private; invitation only (sometimes called "exclusive")
801 3 - Password for new room (if it is a type 2 room)
802 4 - Floor number on which the room should reside (optional)
804 If the create flag is set to 1, the room is created (unless something
805 went wrong and an ERROR return is sent), and the server returns OK, but
806 the session is **not** automatically sent to that room. The client still
807 must perform a GOTO command to go to the new room.
810 FORG (FORGet the current room)
812 This command is used to forget (zap) the current room. For those not
813 familiar with Citadel, this terminology refers to removing the room from
814 a user's own known rooms list, *not* removing the room itself. After a
815 room is forgotten, it no longer shows up in the user's known room list,
816 but it will exist in the user's forgotten room list, and will return to the
817 known room list if the user goes to the room (in Citadel, this is
818 accomplished by explicitly typing the room's name in a <.G>oto command).
820 The command takes no arguments. If the command cannot execute for any
821 reason, ERROR will be returned. ERROR+NOT_LOGGED_IN or ERROR+NOT_HERE may
822 be returned as they apply.
824 If the command succeeds, OK will be returned. At this point, the current
825 room is **undefined**, and the client software is responsible for taking
826 the user to another room before executing any other room commands (usually
827 this will be _BASEROOM_ since it is always there).
830 MESG (read system MESsaGe)
832 This command is used to display system messages and/or help files. The
833 single argument it accepts is the name of the file to display. IT IS CASE
834 SENSITIVE. Citadel/UX looks for these files first in the "messages"
835 subdirectory and then in the "help" subdirectory.
837 If the file is found, LISTING_FOLLOWS is returned, followed by a pathname
838 to the file being displayed. Then the message is printed, in format type 0
839 (see MSG0 command for more information on this). If the file is not found,
842 There are some "well known" names of system messages which client software
843 may expect most servers to carry:
845 hello - Welcome message, to be displayed before the user logs in.
846 changepw - To be displayed whenever the user is prompted for a new
847 password. Warns about picking guessable passwords and such.
848 register - Should be displayed prior to the user entering registration.
849 Warnings about not getting access if not registered, etc.
850 help - Main system help file.
851 goodbye - System logoff banner; display when user logs off.
852 roomaccess - Information about how public rooms and different types of
853 private rooms function with regards to access.
854 unlisted - Tells users not to choose to be unlisted unless they're
855 really paranoid, and warns that aides can still see
856 unlisted userlog entries.
858 Citadel/UX provides these for the Citadel/UX Unix text client. They are
859 probably not very useful for other clients:
861 mainmenu - Main menu (when in idiot mode).
866 saveopt - Options to save a message, abort, etc.
867 entermsg - Displayed just before a message is entered, when in
871 GNUR (Get Next Unvalidated User)
873 This command shows the name of a user that needs to be validated. If there
874 are no unvalidated users, OK is returned. Otherwise, MORE_DATA is returned
875 along with the name of the first unvalidated user the server finds. All of
876 the usual ERROR codes may be returned as well (for example, if the user is
877 not an Aide and cannot validate users).
879 A typical "Validate New Users" command would keep executing this command,
880 and then validating each user it returns, until it returns OK when all new
881 users have been validated.
884 GREG (Get REGistration for user)
886 This command retrieves the registration info for a user, whose name is the
887 command's sole argument. All the usual error messages can be returned. If
888 the command succeeds, LISTING_FOLLOWS is returned, followed by the user's name
889 (retrieved from the userlog, with the right upper and lower case etc.) The
890 contents of the listing contains one field per line, followed by the usual
891 000 on the last line.
893 The following lines are defined. Others WILL be added in the futre, so all
894 software should be written to read the lines it knows about and then ignore
900 Line 4: Street address or PO Box
901 Line 5: City/town/village/etc.
902 Line 6: State/province/etc.
904 Line 8: Telephone number
906 Line 10: Internet e-mail address
908 Users without Aide privileges may retrieve their own registration using
909 this command. This can be accomplished either by passing the user's own
910 name as the argument, or the string "_SELF_". The command will always
911 succeed when used in this manner, unless no user is logged in.
916 This command is used to validate users. Obviously, it can only be executed
917 by users with Aide level access. It should be passed two parameters: the
918 name of the user to validate, and the desired access level
920 If the command succeeds, OK is returned. The user's access level is changed
921 and the "need validation" bit is cleared. If the command fails for any
922 reason, ERROR, ERROR+NO_SUCH_USER, or ERROR+HIGHER_ACCESS_REQUIRED will be
926 EINF (Enter INFo file for room)
928 Transmit the info file for the current room with this command. EINF uses
929 a boolean flag (1 or 0 as the first and only argument to the command) to
930 determine whether the client actually wishes to transmit a new info file, or
931 is merely checking to see if it has permission to do so.
933 If the command cannot succeed, it returns ERROR.
934 If the client is only checking for permission, and permission will be
935 granted, OK is returned.
936 If the client wishes to transmit the new info file, SEND_LISTING is
937 returned, and the client should transmit the text of the info file, ended
938 by the usual 000 on a line by itself.
943 This is a simple user listing. It always succeeds, returning
944 LISTING_FOLLOWS followed by zero or more user records, 000 terminated. The
945 fields on each line are as follows:
950 4. Date/time of last login (Unix format)
953 7. Password (listed only if the user requesting the list is an Aide)
955 Unlisted entries will also be listed to Aides logged into the server, but
956 not to ordinary users.
959 REGI (send REGIstration)
961 Clients will use this command to transmit a user's registration info. If
962 no user is logged in, ERROR+NOT_LOGGED_IN is returned. Otherwise,
963 SEND_LISTING is returned, and the server will expect the following information
964 (terminated by 000 on a line by itself):
967 Line 2: Street address or PO Box
968 Line 3: City/town/village/etc.
969 Line 4: State/province/etc.
971 Line 6: Telephone number
972 Line 7: e-mail address
975 CHEK (CHEcK various things)
977 When logging in, there are various things that need to be checked. This
978 command will return ERROR+NOT_LOGGED_IN if no user is logged in. Otherwise
979 it returns OK and the following parameters:
981 0: Number of new private messages in Mail>
982 1: Nonzero if the user needs to register
983 2: (Relevant to Aides only) Nonzero if new users require validation
988 This command deletes a file from the room's directory, if there is one. The
989 name of the file to delete is the only parameter to be supplied. Wildcards
990 are not acceptable, and any slashes in the filename will be converted to
991 underscores, to prevent unauthorized access to neighboring directories. The
992 possible return codes are:
994 OK - Command succeeded. The file was deleted.
995 ERROR+NOT_LOGGED_IN - Not logged in.
996 ERROR+HIGHER_ACCESS_REQUIRED - Not an Aide or Room Aide.
997 ERROR+NOT_HERE - There is no directory in this room.
998 ERROR+FILE_NOT_FOUND - Requested file was not found.
1003 This command is similar to DELF, except that it moves a file (and its
1004 associated file description) to another room. It should be passed two
1005 parameters: the name of the file to move, and the name of the room to move
1006 the file to. All of the same return codes as DELF may be returned, and also
1007 one additional one: ERROR+NO_SUCH_ROOM, which means that the target room
1008 does not exist. ERROR+NOT_HERE could also mean that the target room does
1009 not have a directory.
1012 NETF (NETwork send a File)
1014 This command is similar to MOVF, except that it attempts to send a file over
1015 the network to another system. It should be passed two parameters: the name
1016 of the file to send, and the node name of the system to send it to. All of
1017 the same return codes as MOVF may be returned, except for ERROR+NO_SUCH_ROOM.
1018 Instead, ERROR+NO_SUCH_SYSTEM may be returned if the name of the target
1021 The name of the originating room will be sent along with the file. Most
1022 implementations will look for a room with the same name at the receiving end
1023 and attempt to place the file there, otherwise it goes into a bit bucket room
1024 for miscellaneous files. This is, however, beyond the scope of this document;
1025 see elsewhere for more details.
1028 RWHO (Read WHO's online)
1030 Displays a list of all users connected to the server. No error codes are
1031 ever returned. LISTING_FOLLOWS will be returned, followed by zero or more
1032 lines containing the following three fields:
1034 0 - Session ID. Citadel/UX fills this with the pid of a server program.
1036 2 - The name of the room the user is currently in. This field might not
1037 be displayed (for example, if the user is in a private room) or it might
1038 contain other information (such as the name of a file the user is
1040 3 - (server v4.03 and above) The name of the host the client is connecting
1041 from, or "localhost" if the client is local.
1042 4 - (server v4.04 and above) Description of the client software being used
1043 5 - The last time, locally to the server, that a command was received from
1044 this client (Note: NOOP's don't count)
1045 6 - The last command received from a client. (NOOP's don't count)
1046 7 - Session flags. These are: + (spoofed address), - (STEALTH mode), *
1047 (posting) and . (idle). (Citserver 5.02 and above)
1049 The listing is terminated, as always, with the string "000" on a line by
1053 OPEN (OPEN a file for download)
1055 This command is used to open a file for downloading. Only one download
1056 file may be open at a time. The only argument to this command is the name
1057 of the file to be opened. The user should already be in the room where the
1058 file resides. Possible return codes are:
1061 ERROR+NOT_HERE (no directory in this room)
1062 ERROR+FILE_NOT_FOUND (could not open the file)
1066 If the file is successfully opened, OK will be returned, along with the
1067 size (in bytes) of the file, the time of last modification (if applicable),
1068 the filename (if known), and the MIME type of the file (if known).
1071 CLOS (CLOSe the download file)
1073 This command is used to close the download file. It returns OK if the
1074 file was successfully closed, or ERROR if there wasn't any file open in the
1078 READ (READ from the download file)
1080 Two arguments are passed to this command. The first is the starting position
1081 in the download file, and the second is the total number of bytes to be
1082 read. If the operation can be performed, BINARY_FOLLOWS will be returned,
1083 along with the number of bytes to follow. Then, immediately following the
1084 newline, will be that many bytes of binary data. The client *must* read
1085 exactly that number of bytes, otherwise the client and server will get out
1088 If the operation cannot be performed, any of the usual error codes will be
1092 UOPN (OPeN a file for Uploading)
1094 This command is similar to OPEN, except that this one is used when the
1095 client wishes to upload a file to the server. The first argument is the name
1096 of the file to create, and the second argument is a one-line comment
1097 describing the contents of the file. Only one upload file may be open at a
1098 time. Possible return codes are:
1101 ERROR+NOT_HERE (no directory in this room)
1102 ERROR+FILE_NOT_FOUND (a name must be specified)
1103 ERROR (miscellaneous errors)
1104 ERROR+ALREADY_EXISTS (a file with the same name already exists)
1107 If OK is returned, the command has succeeded and writes may be performed.
1110 UCLS (CLoSe the Upload file)
1112 Close the file opened with UOPN. An argument of "1" should be passed to
1113 this command to close and save the file; otherwise, the transfer will be
1114 considered aborted and the file will be deleted. This command returns OK
1115 if the operation succeeded or ERROR if it did not.
1118 WRIT (WRITe to the upload file)
1120 If an upload file is open, this command may be used to write to it. The
1121 argument passed to this command is the number of bytes the client wishes to
1122 transmit. An ERROR code will be returned if the operation cannot be
1125 If the operation can be performed, SEND_BINARY will be returned, followed
1126 by the number of bytes the server is expecting. The client must then transmit
1127 exactly that number of bytes. Note that in the current implementation, the
1128 number of bytes the server is expecting will always be the number of bytes
1129 the client requested to transmit, but the client software should never assume
1130 that this will always happen, in case changes are made later.
1133 QUSR (Query for a USeR)
1135 This command is used to check to see if a particular user exists. The only
1136 argument to this command is the name of the user being searched for. If
1137 the user exists, OK is returned, along with the name of the user in the userlog
1138 (so the client software can learn the correct upper/lower casing of the name
1139 if necessary). If the user does not exist, ERROR+NO_SUCH_USER is returned.
1140 No login or current room is required to utilize this command.
1143 OIMG (Open an IMaGe file)
1145 Open an image (graphics) file for downloading. Once opened, the file can be
1146 read as if it were a download file. This implies that an image and a download
1147 cannot be opened at the same time. OIMG returns the same result codes as OPEN.
1149 All images will be in GIF (Graphics Interchange Format). In the case of
1150 Citadel/UX, the server will convert the supplied filename to all lower case,
1151 append the characters ".gif" to the filename, and look for it in the "images"
1152 subdirectory. As with the MESG command, there are several "well known"
1153 images which are likely to exist on most servers:
1155 hello - "Welcome" graphics to be displayed alongside MESG "hello"
1156 goodbye - Logoff banner graphics to be displayed alongside MESG "goodbye"
1157 background - Background image (usually tiled) for graphical clients
1159 The following "special" image names are defined in Citadel/UX server version
1162 _userpic_ - Picture of a user (send the username as the second argument)
1163 _floorpic_ - A graphical floor label (send the floor number as the second
1164 argument). Clients which request a floor picture will display
1165 the picture *instead* of the floor name.
1166 _roompic_ - A graphic associated with the *current* room. Clients which
1167 request a room picture will display the picture in *addition*
1168 to the room name (i.e. it's used for a room banner, as
1169 opposed to the floor picture's use in a floor listing).
1172 NETP (authenticate as network session with system NET Password)
1174 This command is used by client software to identify itself as a transport
1175 session for IGnet/Open BBS to BBS networking. It should be called with
1176 two arguments: the node name of the calling system, and the system net
1177 password for the server. If the authentication succeeds, NETP will return
1178 OK, otherwise, it returns ERROR.
1181 NUOP (Network Upload OPen file)
1183 Open a network spool file for uploading. The client must have already
1184 identified itself as a network session using the NETP command. If the command
1185 returns OK, the client may begin transmitting IGnet/Open spool data using
1186 a series of WRIT commands. When a UCLS command is issued, the spooled data
1187 is entered into the BBS if the argument to UCLS is 1 or discarded if the
1188 argument to UCLS is 0. If the client has not authenticated itself with a
1189 NETP command, ERROR+HIGHER_ACCESS_REQUIRED will be returned.
1192 NDOP (Network Download OPen file)
1194 Open a network spool file for downloading. The client must have already
1195 identified itself as a network session using the NETP command. If the command
1196 returns OK, the client may begin receiving IGnet/Open spool data using
1197 a series of READ commands. When a CLOS command is issued, the spooled data
1198 is deleted from the server and may not be read again. If the client has not
1199 authenticated itself with a NETP command, ERROR+HIGHER_ACCESS_REQUIRED will
1203 LFLR (List all known FLooRs)
1205 On systems supporting floors, this command lists all known floors. The
1206 command accepts no parameters. It will return ERROR+NOT_LOGGED_IN if no
1207 user is logged in. Otherwise it returns LISTING_FOLLOWS and a list of
1208 the available floors, each line consisting of three fields:
1210 1. The floor number associated with the floor
1211 2. The name of the floor
1212 3. Reference count (number of rooms on this floor)
1215 CFLR (Create a new FLooR)
1217 This command is used to create a new floor. It should be passed two
1218 arguments: the name of the new floor to be created, and a 1 or 0 depending
1219 on whether the client is actually creating a floor or merely checking to
1220 see if it has permission to create the floor. The user must be logged in
1221 and have Aide privileges to create a floor.
1223 If the command succeeds, it will return OK followed by the floor number
1224 associated with the new floor. Otherwise, it will return ERROR (plus perhaps
1225 HIGHER_ACCESS_REQUIRED, ALREADY_EXISTS, or INVALID_FLOOR_OPERATION)
1226 followed by a description of why the command failed.
1231 This command is used to delete a floor. It should be passed two
1232 argument: the *number* of the floor to be deleted, and a 1 or 0 depending
1233 on whether the client is actually deleting the floor or merely checking to
1234 see if it has permission to delete the floor. The user must be logged in
1235 and have Aide privileges to delete a floor.
1237 Floors that contain rooms may not be deleted. If there are rooms on a floor,
1238 they must be either deleted or moved to different floors first. This implies
1239 that the Main Floor (floor 0) can never be deleted, since Lobby>, Mail>, and
1240 Aide> all reside on the Main Floor and cannot be deleted.
1242 If the command succeeds, it will return OK. Otherwise it will return
1243 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1244 followed by a description of why the command failed.
1249 Edit the parameters of a floor. The client may pass one or more parameters
1252 1. The number of the floor to be edited
1253 2. The desired new name
1255 More parameters may be added in the future. Any parameters not passed to
1256 the server will remain unchanged. A minimal command would be EFLR and a
1257 floor number -- which would do nothing. EFLR plus the floor number plus a
1258 floor name would change the floor's name.
1260 If the command succeeds, it will return OK. Otherwise it will return
1261 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1264 IDEN (IDENtify the client software)
1266 The client software has the option to identify itself to the server.
1267 Currently, the server does nothing with this information except to write
1268 it to the syslog to satisfy the system administrator's curiosity. Other
1269 uses might become apparent in the future.
1271 The IDEN command should contain five fields: a developer ID number (same as
1272 the server developer ID numbers in the INFO command -- please obtain one if
1273 you are a new developer), a client ID number (which does not have to be
1274 globally unique - only unique within the domain of the developer number),
1275 a version number, a free-form text string describing the client, and the name
1276 of the host the user is located at.
1278 It is up to the server to determine whether to accept the host name or to
1279 use the host name it has detected itself. Generally, if the client is
1280 running on a trusted host (either localhost or a well-known publically
1281 accessible client) it should use the host name transmitted by IDEN,
1282 otherwise it should use the host name it has detected itself.
1284 IDEN always returns OK, but since that's the only way it ever returns
1285 there's no point in checking the result code.
1288 IPGM (identify as an Internal ProGraM)
1290 IPGM is a low-level command that should not be used by normal user clients.
1291 It is used for various utilities to communicate with the server on the same
1292 host. For example, the networker (netproc.c) logs onto the server as an
1293 internal program in order to fetch and store messages. Since user clients
1294 do not utilize this command (or any of its companion commands), developers
1295 writing Citadel-compatible servers need not implement it.
1297 The sole argument to IPGM is the system's internal program password. This
1298 password is generated by the setup program and stored in the config file.
1299 Since internal programs have access to the config file, they know the correct
1302 IPGM returns OK for a correct authentication or ERROR otherwise.
1305 CHAT (enter CHAT mode)
1307 This command functions differently from every other command in the system. It
1308 is used to implement multi-user chat. For this to function, a new transfer
1309 mode, called START_CHAT_MODE, is implemented. If a client does not support
1310 chat mode, it should never send a CHAT command!
1312 In chat mode, messages may arrive asynchronously from the server at any
1313 time. The client may send messages at any time. This allows the arrival of
1314 messages without the client having to poll for them. Arriving messages will
1315 be of the form "user|message", where the "user" portion is, of course, the
1316 name of the user sending the message, and "message" is the message text.
1318 Chat mode ends when the server says it ends. The server will signal the end
1319 of chat mode by transmitting "000" on a line by itself. When the client reads
1320 this line, it must immediately exit from chat mode without sending any
1321 further traffic to the server. The next transmission sent to the server
1322 will be a regular server command.
1324 The Citadel/UX server understands the following commands:
1325 /quit - Exit from chat mode (causes the server to do an 000 end)
1326 /who - List users currently in chat
1327 /whobbs - List users currently in chat and on the bbs
1328 /me - Do an irc-style action.
1329 /join - Join a new "room" in which all messages are only heard by
1330 people in that room.
1331 /msg - /msg <user> <msg> will send the msg to <user> only.
1332 /help - Print help information
1333 NOOP - Do nothing (silently)
1335 Any other non-empty string is treated as message text and will be broadcast
1336 to other users currently in chat.
1339 SEXP (Send EXPress messages)
1341 This is one of two commands which implement "express messages" (also known
1342 as "paging"). An express message is a near-real-time message sent from one
1343 logged in user to another. When an express message is sent, it will be
1344 displayed the next time the target user executes a PEXP or GEXP command.
1346 The SEXP command accepts two arguments: the name of the user to send the
1347 message to, and the text of the message. If the message is successfully
1348 transmitted, OK is returned. If the target user is not logged in or if
1349 anything else goes wrong, ERROR is returned.
1351 If the server supports extended paging, sending a zero-length message
1352 merely checks for the presence of the requested user without actually sending
1353 a message. Sending a message consisting solely of a "-" (hyphen) will cause
1354 the server to return SEND_LISTING if the requested user is logged in, and the
1355 client can then transmit a multi-line page.
1357 The reserved name "broadcast" may be used instead of a user name, to
1358 broadcast an express message to all users currently connected to the server.
1360 Do be aware that if an express message is transmitted to a user who is logged
1361 in using a client that does not check for express messages, the message will
1365 PEXP (Print EXPress messages) ***DEPRECATED***
1367 This command is deprecated; it will eventually disappear from the protocol and
1368 its use is not recommended. Please use the GEXP command instead.
1370 Called without any arguments, PEXP simply dumps out the contents
1371 of any waiting express messages. It returns ERROR if there is a problem,
1372 otherwise it returns LISTING_FOLLOWS followed by all messages.
1374 So how does the client know there are express messages waiting? It could
1375 execute a random PEXP every now and then. Or, it can check the byte in
1376 server return code messages, between the return code and the parameters. In
1377 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1378 an "*" in this position to signify the presence of waiting express messages.
1381 EBIO (Enter BIOgraphy)
1383 Transmit to the server a free-form text file containing a little bit of
1384 information about the user for other users to browse. This is typically
1385 referred to as a 'bio' online. EBIO returns SEND_LISTING if it succeeds,
1386 after which the client is expected to transmit the file, or any of the usual
1387 ERROR codes if it fails.
1390 RBIO (Read BIOgraphy)
1392 Receive from the server a named user's bio. This command should be passed
1393 a single argument - the name of the user whose bio is requested. RBIO returns
1394 LISTING_FOLLOWS plus the bio file if the user exists and has a bio on file,
1395 ERROR+NO_SUCH_USER if the named user does not exist, or ERROR+FILE_NOT_FOUND
1396 if the user exists but has no bio on file.
1399 STEL (enter STEaLth mode)
1401 When in "stealth mode," a user will not show up in the "Who is online"
1402 listing (the RWHO server command). Only Aides may use stealth mode. The
1403 STEL command accepts one argument: a 1 indicating that the user wishes to
1404 enter stealth mode, or a 0 indicating that the user wishes to exit stealth
1405 mode. STEL returns OK if the command succeeded, ERROR+NOT_LOGGED_IN if no
1406 user is logged in, or ERROR+HIGHER_ACCESS_REQUIRED if the user is not an Aide.
1408 The STEL command also makes it so a user does not show up in the chat room
1412 LBIO (List users who have BIOs on file)
1414 This command is self-explanatory. Any user who has used EBIO to place a bio
1415 on file is listed. LBIO almost always returns LISTING_FOLLOWS followed by
1416 this listing, unless it experiences an internal error in which case ERROR
1420 MSG2 (read MeSsaGe, mode 2)
1422 MSG2 follows the same calling convention as MSG0. The difference between
1423 the two commands is that MSG2 outputs messages in standard RFC822 format
1424 rather than in Citadel/UX proprietary format.
1426 This command was implemented in order to make various gateway programs
1427 easier to implement, and to provide some sort of multimedia support in the
1428 future. Keep in mind that when this command is used, all messages will be
1429 output in fixed 80-column format.
1432 MSG3 (read MeSsaGe, mode 3 -- internal command)
1434 MSG3 is for use by internal programs only and should not be utilized by
1435 user-mode clients. It does require IPGM authentication. MSG3 follows the
1436 same calling convention as the other MSG commands, but upon success returns
1437 BINARY_FOLLOWS followed by a data block containing the _raw_ message format
1441 ENT3 (ENTer message, mode 3 -- internal command)
1443 ENT3 is for use by internal programs only and should not be utilized by
1444 user-mode clients. It does require IPGM authentication. This command posts
1445 a raw message straight into the message base without modification or performing
1446 any checks. It accepts the following arguments:
1448 0 - Post flag. This should be set to 1 to post a message. If it is
1449 set to 0, the server only returns OK or ERROR (plus any flags describing
1450 the error) without reading in a message. This is used to verify the operation
1451 before actually transmitting a message.
1452 1 - Recipient. This argument is utilized only for private mail messages.
1453 It is ignored for public messages. It contains, of course, the name of the
1454 recipient of the message.
1455 2 - The size (in bytes) of the message to be transmitted.
1457 ENT3 returns OK to tell the client that a message can be posted, ERROR if
1458 there would be a problem with the operation, or SEND_BINARY followed by a byte
1459 count if it is expecting the message to be transmitted.
1462 TERM (TERMinate another session)
1464 In a multithreaded environment, it sometimes becomes necessary to terminate
1465 a session that is unusable for whatever reason. The TERM command performs
1466 this task. Naturally, only Aides can execute TERM. The command should be
1467 called with a single argument: the session ID (obtained from an RWHO command)
1468 of the session to be terminated.
1470 TERM returns OK if the session was terminated, or ERROR otherwise. Note that
1471 a client program is prohibited from terminating the session it is currently
1475 NSET (Network SETup commands)
1477 Aides may use this command to configure the networker. This command's
1478 parameters are passed directly to the 'netsetup' command line utility. If
1479 netsetup returns a non-zero exit code, ERROR is returned, along with the
1480 error message (if any). If netsetup returns a zero (success) exit code,
1481 LISTING_FOLLOWS is returned, followed by zero or more lines of output (since
1482 netsetup may have information to display, such as a room or node list) and
1483 the usual '000' listing terminator.
1486 DOWN (shut DOWN the server)
1488 This command, which may only be executed by an Aide, immediately shuts down
1489 the server. It is only implemented on servers on which such an operation is
1490 possible, such as a multithreaded Citadel engine. The server does not restart.
1491 DOWN returns OK if the user is allowed to shut down the server, in which case
1492 the client program should expect the connection to be immediately broken.
1495 SCDN (Schedule or Cancel a shutDowN)
1497 SCDN sets or clears the "scheduled shutdown" flag. Pass this command a 1 or
1498 0 to respectively set or clear the flag. When the "scheduled shutdown" flag is
1499 set, the server will be shut down when there are no longer any users logged in.
1500 Any value other than 0 or 1 will not change the flag, only report its state.
1501 No users will be kicked off the system, and in fact the server is still available
1502 for new connections. The command returns ERROR if it fails; otherwise, it
1503 returns OK followed by a number representing the current state of the flag.
1506 EMSG (Enter a system MeSsaGe)
1508 This is the opposite of the MESG command - it allows the creation and editing
1509 of system messages. The only argument passed to EMSG is the name of the
1510 file being transmitted. If the file exists in any system message directory
1511 on the server it will be overwritten, otherwise a new file is created. EMSG
1512 returns SEND_LISTING on success or ERROR+HIGHER_ACCESS_REQUIRED if the user
1515 Typical client software would use MESG to retrieve any existing message into
1516 an edit buffer, then present an editor to the user and run EMSG if the changes
1520 UIMG (Upload an IMaGe file)
1522 UIMG is complemenary to OIMG; it is used to upload an image to the server.
1523 The first parameter supplied to UIMG should be 0 if the client is only checking
1524 for permission to upload, or 1 if the client is actually attempting to begin
1525 the upload operation. The second argument is the name of the file to be
1526 transmitted. In Citadel/UX, the filename is converted to all lower case,
1527 appended with the characters ".gif", and stored in the "images" directory.
1529 UIMG returns OK if the client has permission to perform the requested upload,
1530 or ERROR+HIGHER_ACCESS_REQUIRED otherwise. If the client requested to begin
1531 the operation (first parameter set to 1), an upload file is opened, and the
1532 client should begin writing to it with WRIT commands, then close it with a
1535 The supplied filename should be one of:
1537 -> _userpic_ (Server will attempt to write to the user's online photo)
1538 -> Any of the "well known" filenames described in the writeup for the
1541 ----------------------------------------------
1542 The following are for citserver 5.02 and above
1543 ----------------------------------------------
1545 HCHG (Hostname CHanGe)
1547 HCHG is a command, usable by any user, that allows a user to change their RWHO
1548 host value. This will mask a client's originating hostname from normal
1549 users; access level 6 and higher see an entry right underneath the spoofed
1550 entry listing the actual hostname the user originates from.
1552 The format of an HCHG command is:
1556 If a HCHG command is successful, the value OK (200) is returned.
1559 RCHG (Roomname CHanGe)
1561 RCHG is a command, usable by any user, that allows a user to change their RWHO
1562 room value. This will mask a client's roomname from normal users; access
1563 level 6 and higher see an entry right underneath the spoofed entry listing
1564 the actual room the user is in.
1566 The format of an RCHG command is:
1570 If a RCHG command is successful, the value OK (200) is returned.
1573 UCHG (Username CHanGe)
1575 UCHG is an aide-level command which allows an aide to effectively change their
1576 username. If this value is blank, the user goes into stealth mode (see
1578 will show up as being from the real username in this mode, however. In
1579 addition, the RWHO listing will include both the spoofed and real usernames.
1581 The format of an UCHG command is:
1585 If a UCHG command is successful, the value OK (200) is returned.
1588 TIME (get server local TIME)
1590 TIME returns OK followed by the current time measured in seconds since
1591 00:00:00 GMT, Jan 1, 1970 (standard Unix format).
1593 This is used in allowing a client to calculate idle times.
1596 AGUP (Administrative Get User Parameters)
1597 ASUP (Administrative Set User Parameters)
1599 These commands are only executable by Aides and by server extensions running
1600 at system-level. They are used to get/set any and all parameters relating to
1601 a user account. AGUP requires only one argument: the name of the user in
1602 question. SGUP requires all of the parameters to be set. The parameters are
1603 as follows, and are common to both commands:
1607 2 - Flags (see citadel.h)
1612 7 - Timestamp of last call
1613 8 - Purge time (in days) for this user (or 0 to use system default)
1615 Upon success, AGUP returns OK followed by all these parameters, and ASUP
1616 simply returns OK. If the client has insufficient access to perform the
1617 requested operation, ERROR+HIGHER_ACCESS_REQUIRED is returned. If the
1618 requested user does not exist, ERROR+NO_SUCH_USER is returned.
1622 GPEX (Get Policy for message EXpiration)
1624 Returns the policy of the current room, floor, or site regarding the automatic
1625 purging (expiration) of messages. The following policies are available:
1626 0 - Fall back to the policy of the next higher level. If this is a room,
1627 use the floor's default policy. If this is a floor, use the system
1628 default policy. This is an invalid value for the system policy.
1629 1 - Do not purge messages automatically.
1630 2 - Purge by message count. (Requires a value: number of messages)
1631 3 - Purge by message age. (Requires a value: number of days)
1633 The format of this command is: GPEX <which>
1634 The value of <which> must be one of: "room" "floor" "site"
1636 If successful, GPEX returns OK followed by <policy>|<value>.
1640 SPEX (Set Polict for message EXpiration)
1642 Sets the policy of the current room, floor, or site regarding the automatic
1643 purging (expiration) of messages. See the writeup for the GPEX command for
1644 the list of available policies.
1646 The format of this command is: SPEX <which>|<policy>|<value>
1647 The value of <which> must be one of: "room" "floor" "site"
1649 If successful, GPEX returns OK; otherwise, an ERROR code is returned.
1653 CONF (get or set global CONFiguration options)
1655 Retrieves or sets various system-wide configuration and policy options. This
1656 command is only available to Aides. The sole parameter accepted is a command,
1657 which should be either GET or SET. If the GET command succeeds, CONF will
1658 return LISTING_FOLLOWS followed by the fields described below, one line at a
1659 time. If the SET command succeeds, CONF will return SEND_LISTING and expect
1660 the fields described below, one line at a time (don't worry about other fields
1661 being added in the future; if a 'short' configuration list is sent, the missing
1662 values at the end will be left unchanged on the system). If either command
1663 fails for any reason, ERROR is returned.
1665 The configuration lines are as follows:
1668 2. Fully qualified domain name
1669 3. Human-readable node name
1670 4. Landline telephone number of this system
1671 5. Flag (0 or 1) - creator of private room automatically becomes room aide
1672 6. Server connection idle timeout (in seconds)
1673 7. Initial access level for new users
1674 8. Flag (0 or 1) - require registration for new users
1675 9. Flag (0 or 1) - automatically move Problem User messages to twit room
1676 10. Name of twit room
1677 11. Text of <more> prompt
1678 12. Flag (0 or 1) - restrict access to Internet mail
1679 13. Geographic location of this system
1680 14. Name of the system administrator
1681 15. Number of maximum concurrent sessions allowed on the server
1682 16. Password for server-to-server networking
1683 17. Default purge time (in days) for users
1684 18. Default purge time (in days) for rooms
1685 19. Name of room to log express messages to (or a zero-length name for none)
1686 20. Access level required to create rooms
1687 21. Maximum message length which may be entered into the system
1691 EXPI (EXPIre system objects)
1693 Begins purge operations for objects which, according to site policy, are
1694 "old" and should be removed. EXPI should be called with one argument, one of:
1696 "messages" (purge old messages out of each room)
1697 "users" (purge old users from the userlog)
1698 "rooms" (remove rooms which have not been posted in for some time)
1699 "visits" (purge dereferenced user/room relationship records)
1701 EXPI returns OK (probably after a long delay while it does its work) if it
1702 succeeds; otherwise it returns an ERROR code.
1704 This command is probably temporary, until we can work some sort of scheduler
1705 into the system. It is implemented in the serv_expire module.
1709 MSG4 (read MeSsaGe, mode 4 -- enumerate MIME parts)
1711 FIX ... do the writeup for this once it's done.
1715 OPNA (OPeN Attachment)
1717 Opens, as a download file, a component of a MIME-encoded message. The two
1718 parameters which must be passed to this command are the message number and the
1719 name of the desired section. If the message or section does not exist, an
1720 appropriate ERROR code will be returned; otherwise, if the open is successful,
1721 this command will succeed returning the same information as an OPEN command.
1724 GEXP (Get EXPress messages)
1726 This is a more sophisticated way of retrieving express messages than the old
1727 PEXP method. If there are no express messages waiting, PEXP returns ERROR;
1728 otherwise, it returns LISTING_FOLLOWS and the following arguments:
1730 0 - a boolean value telling the client whether there are any additional
1731 express messages waiting following this one
1732 1 - a Unix-style timestamp
1733 2 - flags (see server.h for more info)
1734 3 - the name of the sender
1735 4 - the node this message originated on (for future support of PIP, ICQ, etc.)
1737 The text sent to the client will be the body of the express message.
1739 So how does the client know there are express messages waiting? It could
1740 execute a random GEXP every now and then. Or, it can check the byte in
1741 server return code messages, between the return code and the parameters. In
1742 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1743 an "*" in this position to signify the presence of waiting express messages.
1747 CICQ (Citadel ICQ metaclient setup)
1750 This command is most likely a temporary one. Citadel will eventually have
1751 more robust functionality for abstract configuration screens, and when that
1752 happens, this command will certainly be migrated there. If you're developing
1753 a client, don't spend a lot of time working on ICQ screens.
1755 If a Citadel server has the ICQ Metaclient installed, this command is used
1756 to configure it. It has several usages:
1760 This tells Citadel the user's ICQ uin (second argument) and password (third
1761 argument). When called in this fashion, CICQ will return either OK or ERROR.
1762 It should be noted, however, that the only way an ERROR code can be returned
1763 is if the uin and/or password is not supplied. Authentication failures cannot
1764 be immediately detected, because the ICQ protocol is asynchronous.
1768 Request the current contact list. If successful, CICQ will return
1769 LISTING_FOLLOWS followed by zero or more contacts in the format
1775 Upload a new contact list. If successful, CICQ will return SEND_LISTING
1776 after which the client should transmit zero or more uin's, one per line. The
1777 server will then attempt to contact the ICQ server to determine nicknames
1782 Always returns OK followed by a 1 (connected to ICQ) or 0 (not connected).