lisp/gnus/pop3.el

   1 ;;; pop3.el --- Post Office Protocol (RFC 1460) interface
   2
   3 ;; Copyright (C) 1996-2012 Free Software Foundation, Inc.
   4
   5 ;; Author: Richard L. Pieri <ratinox@peorth.gweep.net>
   6 ;; Maintainer: FSF
   7 ;; Keywords: mail
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software: you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation, either version 3 of the License, or
  14 ;; (at your option) any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;; Most of the standard Post Office Protocol version 3 (RFC 1460) commands
  27 ;; are implemented.  The LIST command has not been implemented due to lack
  28 ;; of actual usefulness.
  29 ;; The optional POP3 command TOP has not been implemented.
  30
  31 ;; This program was inspired by Kyle E. Jones's vm-pop program.
  32
  33 ;;; Code:
  34
  35 (eval-when-compile (require 'cl))
  36
  37 (eval-and-compile
  38   ;; In Emacs 24, `open-protocol-stream' is an autoloaded alias for
  39   ;; `make-network-stream'.
  40   (unless (fboundp 'open-protocol-stream)
  41     (require 'proto-stream)))
  42
  43 (require 'mail-utils)
  44 (defvar parse-time-months)
  45
  46 (defgroup pop3 nil
  47   "Post Office Protocol."
  48   :group 'mail
  49   :group 'mail-source)
  50
  51 (defcustom pop3-maildrop (or (user-login-name)
  52                              (getenv "LOGNAME")
  53                              (getenv "USER"))
  54   "*POP3 maildrop."
  55   :version "22.1" ;; Oort Gnus
  56   :type 'string
  57   :group 'pop3)
  58
  59 (defcustom pop3-mailhost (or (getenv "MAILHOST") ;; nil -> mismatch
  60                              "pop3")
  61   "*POP3 mailhost."
  62   :version "22.1" ;; Oort Gnus
  63   :type 'string
  64   :group 'pop3)
  65
  66 (defcustom pop3-port 110
  67   "*POP3 port."
  68   :version "22.1" ;; Oort Gnus
  69   :type 'number
  70   :group 'pop3)
  71
  72 (defcustom pop3-password-required t
  73   "*Non-nil if a password is required when connecting to POP server."
  74   :version "22.1" ;; Oort Gnus
  75   :type 'boolean
  76   :group 'pop3)
  77
  78 ;; Should this be customizable?
  79 (defvar pop3-password nil
  80   "*Password to use when connecting to POP server.")
  81
  82 (defcustom pop3-authentication-scheme 'pass
  83   "*POP3 authentication scheme.
  84 Defaults to `pass', for the standard USER/PASS authentication.  The other
  85 valid value is 'apop'."
  86   :type '(choice (const :tag "Normal user/password" pass)
  87                  (const :tag "APOP" apop))
  88   :version "22.1" ;; Oort Gnus
  89   :group 'pop3)
  90
  91 (defcustom pop3-stream-length 100
  92   "How many messages should be requested at one time.
  93 The lower the number, the more latency-sensitive the fetching
  94 will be.  If your pop3 server doesn't support streaming at all,
  95 set this to 1."
  96   :type 'number
  97   :version "24.1"
  98   :group 'pop3)
  99
 100 (defcustom pop3-leave-mail-on-server nil
 101   "*Non-nil if the mail is to be left on the POP server after fetching.
 102
 103 If `pop3-leave-mail-on-server' is non-nil the mail is to be left
 104 on the POP server after fetching.  Note that POP servers maintain
 105 no state information between sessions, so what the client
 106 believes is there and what is actually there may not match up.
 107 If they do not, then you may get duplicate mails or the whole
 108 thing can fall apart and leave you with a corrupt mailbox."
 109   ;; We can't use the UILD support from XEmacs mail-lib or cvs.m17n.org:
 110   ;; http://thread.gmane.org/v9lld8fml4.fsf@marauder.physik.uni-ulm.de
 111   ;; http://thread.gmane.org/b9yy8hzy9ej.fsf@jpl.org
 112   ;; Any volunteer to re-implement this?
 113   :version "22.1" ;; Oort Gnus
 114   :type 'boolean
 115   :group 'pop3)
 116
 117 (defvar pop3-timestamp nil
 118   "Timestamp returned when initially connected to the POP server.
 119 Used for APOP authentication.")
 120
 121 (defvar pop3-read-point nil)
 122 (defvar pop3-debug nil)
 123
 124 ;; Borrowed from nnheader-accept-process-output in nnheader.el.  See the
 125 ;; comments there for explanations about the values.
 126
 127 (eval-and-compile
 128   (if (and (fboundp 'nnheader-accept-process-output)
 129            (boundp 'nnheader-read-timeout))
 130       (defalias 'pop3-accept-process-output 'nnheader-accept-process-output)
 131     ;; Borrowed from `nnheader.el':
 132     (defvar pop3-read-timeout
 133       (if (string-match "windows-nt\\|os/2\\|cygwin"
 134                         (symbol-name system-type))
 135           1.0
 136         0.01)
 137       "How long pop3 should wait between checking for the end of output.
 138 Shorter values mean quicker response, but are more CPU intensive.")
 139     (defun pop3-accept-process-output (process)
 140       (accept-process-output
 141        process
 142        (truncate pop3-read-timeout)
 143        (truncate (* (- pop3-read-timeout
 144                        (truncate pop3-read-timeout))
 145                     1000))))))
 146
 147 ;;;###autoload
 148 (defun pop3-movemail (file)
 149   "Transfer contents of a maildrop to the specified FILE.
 150 Use streaming commands."
 151   (let* ((process (pop3-open-server pop3-mailhost pop3-port))
 152          message-count message-total-size)
 153     (pop3-logon process)
 154     (with-current-buffer (process-buffer process)
 155       (let ((size (pop3-stat process)))
 156         (setq message-count (car size)
 157               message-total-size (cadr size)))
 158       (when (> message-count 0)
 159         (pop3-send-streaming-command
 160          process "RETR" message-count message-total-size)
 161         (pop3-write-to-file file)
 162         (unless pop3-leave-mail-on-server
 163           (pop3-send-streaming-command
 164            process "DELE" message-count nil))))
 165     (pop3-quit process)
 166     t))
 167
 168 (defun pop3-send-streaming-command (process command count total-size)
 169   (erase-buffer)
 170   (let ((i 1)
 171         (start-point (point-min))
 172         (waited-for 0))
 173     (while (>= count i)
 174       (process-send-string process (format "%s %d\r\n" command i))
 175       ;; Only do 100 messages at a time to avoid pipe stalls.
 176       (when (zerop (% i pop3-stream-length))
 177         (setq start-point
 178               (pop3-wait-for-messages process pop3-stream-length
 179                                       total-size start-point))
 180         (incf waited-for pop3-stream-length))
 181       (incf i))
 182     (pop3-wait-for-messages process (- count waited-for)
 183                             total-size start-point)))
 184
 185 (defun pop3-wait-for-messages (process count total-size start-point)
 186   (while (> count 0)
 187     (goto-char start-point)
 188     (while (or (and (re-search-forward "^\\+OK" nil t)
 189                     (or (not total-size)
 190                         (re-search-forward "^\\.\r?\n" nil t)))
 191                (re-search-forward "^-ERR " nil t))
 192       (decf count)
 193       (setq start-point (point)))
 194     (unless (memq (process-status process) '(open run))
 195       (error "pop3 process died"))
 196     (when total-size
 197       (message "pop3 retrieved %dKB (%d%%)"
 198                (truncate (/ (buffer-size) 1000))
 199                (truncate (* (/ (* (buffer-size) 1.0)
 200                                total-size) 100))))
 201     (pop3-accept-process-output process))
 202   start-point)
 203
 204 (defun pop3-write-to-file (file)
 205   (let ((pop-buffer (current-buffer))
 206         (start (point-min))
 207         beg end
 208         temp-buffer)
 209     (with-temp-buffer
 210       (setq temp-buffer (current-buffer))
 211       (with-current-buffer pop-buffer
 212         (goto-char (point-min))
 213         (while (re-search-forward "^\\+OK" nil t)
 214           (forward-line 1)
 215           (setq beg (point))
 216           (when (re-search-forward "^\\.\r?\n" nil t)
 217             (setq start (point))
 218             (forward-line -1)
 219             (setq end (point)))
 220           (with-current-buffer temp-buffer
 221             (goto-char (point-max))
 222             (let ((hstart (point)))
 223               (insert-buffer-substring pop-buffer beg end)
 224               (pop3-clean-region hstart (point))
 225               (goto-char (point-max))
 226               (pop3-munge-message-separator hstart (point))
 227               (goto-char (point-max))))))
 228       (let ((coding-system-for-write 'binary))
 229         (goto-char (point-min))
 230         ;; Check whether something inserted a newline at the start and
 231         ;; delete it.
 232         (when (eolp)
 233           (delete-char 1))
 234         (write-region (point-min) (point-max) file nil 'nomesg)))))
 235
 236 (defun pop3-logon (process)
 237   (let ((pop3-password pop3-password))
 238     ;; for debugging only
 239     (if pop3-debug (switch-to-buffer (process-buffer process)))
 240     ;; query for password
 241     (if (and pop3-password-required (not pop3-password))
 242         (setq pop3-password
 243               (read-passwd (format "Password for %s: " pop3-maildrop))))
 244     (cond ((equal 'apop pop3-authentication-scheme)
 245            (pop3-apop process pop3-maildrop))
 246           ((equal 'pass pop3-authentication-scheme)
 247            (pop3-user process pop3-maildrop)
 248            (pop3-pass process))
 249           (t (error "Invalid POP3 authentication scheme")))))
 250
 251 (defun pop3-get-message-count ()
 252   "Return the number of messages in the maildrop."
 253   (let* ((process (pop3-open-server pop3-mailhost pop3-port))
 254          message-count
 255          (pop3-password pop3-password))
 256     ;; for debugging only
 257     (if pop3-debug (switch-to-buffer (process-buffer process)))
 258     ;; query for password
 259     (if (and pop3-password-required (not pop3-password))
 260         (setq pop3-password
 261               (read-passwd (format "Password for %s: " pop3-maildrop))))
 262     (cond ((equal 'apop pop3-authentication-scheme)
 263            (pop3-apop process pop3-maildrop))
 264           ((equal 'pass pop3-authentication-scheme)
 265            (pop3-user process pop3-maildrop)
 266            (pop3-pass process))
 267           (t (error "Invalid POP3 authentication scheme")))
 268     (setq message-count (car (pop3-stat process)))
 269     (pop3-quit process)
 270     message-count))
 271
 272 (defcustom pop3-stream-type nil
 273   "*Transport security type for POP3 connections.
 274 This may be either nil (plain connection), `ssl' (use an
 275 SSL/TSL-secured stream) or `starttls' (use the starttls mechanism
 276 to turn on TLS security after opening the stream).  However, if
 277 this is nil, `ssl' is assumed for connections to port
 278 995 (pop3s)."
 279   :version "23.1" ;; No Gnus
 280   :group 'pop3
 281   :type '(choice (const :tag "Plain" nil)
 282                  (const :tag "SSL/TLS" ssl)
 283                  (const starttls)))
 284
 285 (eval-and-compile
 286   (if (fboundp 'set-process-query-on-exit-flag)
 287       (defalias 'pop3-set-process-query-on-exit-flag
 288         'set-process-query-on-exit-flag)
 289     (defalias 'pop3-set-process-query-on-exit-flag
 290       'process-kill-without-query)))
 291
 292 (defun pop3-open-server (mailhost port)
 293   "Open TCP connection to MAILHOST on PORT.
 294 Returns the process associated with the connection."
 295   (let ((coding-system-for-read 'binary)
 296         (coding-system-for-write 'binary)
 297         result)
 298     (with-current-buffer
 299         (get-buffer-create (concat " trace of POP session to "
 300                                    mailhost))
 301       (erase-buffer)
 302       (setq pop3-read-point (point-min))
 303       (setq result
 304             (open-protocol-stream
 305              "POP" (current-buffer) mailhost port
 306              :type (cond
 307                     ((or (eq pop3-stream-type 'ssl)
 308                          (and (not pop3-stream-type)
 309                               (member port '(995 "pop3s"))))
 310                      'tls)
 311                     (t
 312                      (or pop3-stream-type 'network)))
 313              :capability-command "CAPA\r\n"
 314              :end-of-command "^\\(-ERR\\|+OK\\).*\n"
 315              :end-of-capability "^\\.\r?\n\\|^-ERR"
 316              :success "^\\+OK.*\n"
 317              :return-list t
 318              :starttls-function
 319              (lambda (capabilities)
 320                (and (string-match "\\bSTLS\\b" capabilities)
 321                     "STLS\r\n"))))
 322       (when result
 323         (let ((response (plist-get (cdr result) :greeting)))
 324           (setq pop3-timestamp
 325                 (substring response (or (string-match "<" response) 0)
 326                            (+ 1 (or (string-match ">" response) -1)))))
 327         (pop3-set-process-query-on-exit-flag (car result) nil)
 328         (erase-buffer)
 329         (car result)))))
 330
 331 ;; Support functions
 332
 333 (defun pop3-send-command (process command)
 334   (set-buffer (process-buffer process))
 335   (goto-char (point-max))
 336   ;; (if (= (aref command 0) ?P)
 337   ;;     (insert "PASS <omitted>\r\n")
 338   ;;   (insert command "\r\n"))
 339   (setq pop3-read-point (point))
 340   (goto-char (point-max))
 341   (process-send-string process (concat command "\r\n")))
 342
 343 (defun pop3-read-response (process &optional return)
 344   "Read the response from the server.
 345 Return the response string if optional second argument is non-nil."
 346   (let ((case-fold-search nil)
 347         match-end)
 348     (with-current-buffer (process-buffer process)
 349       (goto-char pop3-read-point)
 350       (while (and (memq (process-status process) '(open run))
 351                   (not (search-forward "\r\n" nil t)))
 352         (pop3-accept-process-output process)
 353         (goto-char pop3-read-point))
 354       (setq match-end (point))
 355       (goto-char pop3-read-point)
 356       (if (looking-at "-ERR")
 357           (error "%s" (buffer-substring (point) (- match-end 2)))
 358         (if (not (looking-at "+OK"))
 359             (progn (setq pop3-read-point match-end) nil)
 360           (setq pop3-read-point match-end)
 361           (if return
 362               (buffer-substring (point) match-end)
 363             t)
 364           )))))
 365
 366 (defun pop3-clean-region (start end)
 367   (setq end (set-marker (make-marker) end))
 368   (save-excursion
 369     (goto-char start)
 370     (while (and (< (point) end) (search-forward "\r\n" end t))
 371       (replace-match "\n" t t))
 372     (goto-char start)
 373     (while (and (< (point) end) (re-search-forward "^\\." end t))
 374       (replace-match "" t t)
 375       (forward-char)))
 376   (set-marker end nil))
 377
 378 ;; Copied from message-make-date.
 379 (defun pop3-make-date (&optional now)
 380   "Make a valid date header.
 381 If NOW, use that time instead."
 382   (require 'parse-time)
 383   (let* ((now (or now (current-time)))
 384          (zone (nth 8 (decode-time now)))
 385          (sign "+"))
 386     (when (< zone 0)
 387       (setq sign "-")
 388       (setq zone (- zone)))
 389     (concat
 390      (format-time-string "%d" now)
 391      ;; The month name of the %b spec is locale-specific.  Pfff.
 392      (format " %s "
 393              (capitalize (car (rassoc (nth 4 (decode-time now))
 394                                       parse-time-months))))
 395      (format-time-string "%Y %H:%M:%S " now)
 396      ;; We do all of this because XEmacs doesn't have the %z spec.
 397      (format "%s%02d%02d" sign (/ zone 3600) (/ (% zone 3600) 60)))))
 398
 399 (defun pop3-munge-message-separator (start end)
 400   "Check to see if a message separator exists.  If not, generate one."
 401   (save-excursion
 402     (save-restriction
 403       (narrow-to-region start end)
 404       (goto-char (point-min))
 405       (if (not (or (looking-at "From .?") ; Unix mail
 406                    (looking-at "\001\001\001\001\n") ; MMDF
 407                    (looking-at "BABYL OPTIONS:") ; Babyl
 408                    ))
 409           (let* ((from (mail-strip-quoted-names (mail-fetch-field "From")))
 410                  (tdate (mail-fetch-field "Date"))
 411                  (date (split-string (or (and tdate
 412                                               (not (string= "" tdate))
 413                                               tdate)
 414                                          (pop3-make-date))
 415                                      " "))
 416                  (From_))
 417             ;; sample date formats I have seen
 418             ;; Date: Tue, 9 Jul 1996 09:04:21 -0400 (EDT)
 419             ;; Date: 08 Jul 1996 23:22:24 -0400
 420             ;; should be
 421             ;; Tue Jul 9 09:04:21 1996
 422
 423             ;; Fixme: This should use timezone on the date field contents.
 424             (setq date
 425                   (cond ((not date)
 426                          "Tue Jan 1 00:00:0 1900")
 427                         ((string-match "[A-Z]" (nth 0 date))
 428                          (format "%s %s %s %s %s"
 429                                  (nth 0 date) (nth 2 date) (nth 1 date)
 430                                  (nth 4 date) (nth 3 date)))
 431                         (t
 432                          ;; this really needs to be better but I don't feel
 433                          ;; like writing a date to day converter.
 434                          (format "Sun %s %s %s %s"
 435                                  (nth 1 date) (nth 0 date)
 436                                  (nth 3 date) (nth 2 date)))
 437                         ))
 438             (setq From_ (format "\nFrom %s  %s\n" from date))
 439             (while (string-match "," From_)
 440               (setq From_ (concat (substring From_ 0 (match-beginning 0))
 441                                   (substring From_ (match-end 0)))))
 442             (goto-char (point-min))
 443             (insert From_)
 444             (if (search-forward "\n\n" nil t)
 445                 nil
 446               (goto-char (point-max))
 447               (insert "\n"))
 448             (let ((size (- (point-max) (point))))
 449               (forward-line -1)
 450               (insert (format "Content-Length: %s\n" size)))
 451             )))))
 452
 453 ;; The Command Set
 454
 455 ;; AUTHORIZATION STATE
 456
 457 (defun pop3-user (process user)
 458   "Send USER information to POP3 server."
 459   (pop3-send-command process (format "USER %s" user))
 460   (let ((response (pop3-read-response process t)))
 461     (if (not (and response (string-match "+OK" response)))
 462         (error "USER %s not valid" user))))
 463
 464 (defun pop3-pass (process)
 465   "Send authentication information to the server."
 466   (pop3-send-command process (format "PASS %s" pop3-password))
 467   (let ((response (pop3-read-response process t)))
 468     (if (not (and response (string-match "+OK" response)))
 469         (pop3-quit process))))
 470
 471 (defun pop3-apop (process user)
 472   "Send alternate authentication information to the server."
 473   (let ((pass pop3-password))
 474     (if (and pop3-password-required (not pass))
 475         (setq pass
 476               (read-passwd (format "Password for %s: " pop3-maildrop))))
 477     (if pass
 478         (let ((hash (md5 (concat pop3-timestamp pass) nil nil 'binary)))
 479           (pop3-send-command process (format "APOP %s %s" user hash))
 480           (let ((response (pop3-read-response process t)))
 481             (if (not (and response (string-match "+OK" response)))
 482                 (pop3-quit process)))))
 483     ))
 484
 485 ;; TRANSACTION STATE
 486
 487 (defun pop3-stat (process)
 488   "Return the number of messages in the maildrop and the maildrop's size."
 489   (pop3-send-command process "STAT")
 490   (let ((response (pop3-read-response process t)))
 491     (list (string-to-number (nth 1 (split-string response " ")))
 492           (string-to-number (nth 2 (split-string response " "))))
 493     ))
 494
 495 (defun pop3-list (process &optional msg)
 496   "If MSG is nil, return an alist of (MESSAGE-ID . SIZE) pairs.
 497 Otherwise, return the size of the message-id MSG"
 498   (pop3-send-command process (if msg
 499                                  (format "LIST %d" msg)
 500                                "LIST"))
 501   (let ((response (pop3-read-response process t)))
 502     (if msg
 503         (string-to-number (nth 2 (split-string response " ")))
 504       (let ((start pop3-read-point) end)
 505         (with-current-buffer (process-buffer process)
 506           (while (not (re-search-forward "^\\.\r\n" nil t))
 507             (pop3-accept-process-output process)
 508             (goto-char start))
 509           (setq pop3-read-point (point-marker))
 510           (goto-char (match-beginning 0))
 511           (setq end (point-marker))
 512           (mapcar #'(lambda (s) (let ((split (split-string s " ")))
 513                                   (cons (string-to-number (nth 0 split))
 514                                         (string-to-number (nth 1 split)))))
 515                   (split-string (buffer-substring start end) "\r\n" t)))))))
 516
 517 (defun pop3-retr (process msg crashbuf)
 518   "Retrieve message-id MSG to buffer CRASHBUF."
 519   (pop3-send-command process (format "RETR %s" msg))
 520   (pop3-read-response process)
 521   (let ((start pop3-read-point) end)
 522     (with-current-buffer (process-buffer process)
 523       (while (not (re-search-forward "^\\.\r\n" nil t))
 524         (unless (memq (process-status process) '(open run))
 525           (error "pop3 server closed the connection"))
 526         (pop3-accept-process-output process)
 527         (goto-char start))
 528       (setq pop3-read-point (point-marker))
 529       ;; this code does not seem to work for some POP servers...
 530       ;; and I cannot figure out why not.
 531       ;;      (goto-char (match-beginning 0))
 532       ;;      (backward-char 2)
 533       ;;      (if (not (looking-at "\r\n"))
 534       ;;          (insert "\r\n"))
 535       ;;      (re-search-forward "\\.\r\n")
 536       (goto-char (match-beginning 0))
 537       (setq end (point-marker))
 538       (pop3-clean-region start end)
 539       (pop3-munge-message-separator start end)
 540       (with-current-buffer crashbuf
 541         (erase-buffer))
 542       (copy-to-buffer crashbuf start end)
 543       (delete-region start end)
 544       )))
 545
 546 (defun pop3-dele (process msg)
 547   "Mark message-id MSG as deleted."
 548   (pop3-send-command process (format "DELE %s" msg))
 549   (pop3-read-response process))
 550
 551 (defun pop3-noop (process msg)
 552   "No-operation."
 553   (pop3-send-command process "NOOP")
 554   (pop3-read-response process))
 555
 556 (defun pop3-last (process)
 557   "Return highest accessed message-id number for the session."
 558   (pop3-send-command process "LAST")
 559   (let ((response (pop3-read-response process t)))
 560     (string-to-number (nth 1 (split-string response " ")))
 561     ))
 562
 563 (defun pop3-rset (process)
 564   "Remove all delete marks from current maildrop."
 565   (pop3-send-command process "RSET")
 566   (pop3-read-response process))
 567
 568 ;; UPDATE
 569
 570 (defun pop3-quit (process)
 571   "Close connection to POP3 server.
 572 Tell server to remove all messages marked as deleted, unlock the maildrop,
 573 and close the connection."
 574   (pop3-send-command process "QUIT")
 575   (pop3-read-response process t)
 576   (if process
 577       (with-current-buffer (process-buffer process)
 578         (goto-char (point-max))
 579         (delete-process process))))
 580 \f
 581 ;; Summary of POP3 (Post Office Protocol version 3) commands and responses
 582
 583 ;;; AUTHORIZATION STATE
 584
 585 ;; Initial TCP connection
 586 ;; Arguments: none
 587 ;; Restrictions: none
 588 ;; Possible responses:
 589 ;;  +OK [POP3 server ready]
 590
 591 ;; USER name
 592 ;; Arguments: a server specific user-id (required)
 593 ;; Restrictions: authorization state [after unsuccessful USER or PASS
 594 ;; Possible responses:
 595 ;;  +OK [valid user-id]
 596 ;;  -ERR [invalid user-id]
 597
 598 ;; PASS string
 599 ;; Arguments: a server/user-id specific password (required)
 600 ;; Restrictions: authorization state, after successful USER
 601 ;; Possible responses:
 602 ;;  +OK [maildrop locked and ready]
 603 ;;  -ERR [invalid password]
 604 ;;  -ERR [unable to lock maildrop]
 605
 606 ;; STLS      (RFC 2595)
 607 ;; Arguments: none
 608 ;; Restrictions: Only permitted in AUTHORIZATION state.
 609 ;; Possible responses:
 610 ;;  +OK
 611 ;;  -ERR
 612
 613 ;;; TRANSACTION STATE
 614
 615 ;; STAT
 616 ;; Arguments: none
 617 ;; Restrictions: transaction state
 618 ;; Possible responses:
 619 ;;  +OK nn mm [# of messages, size of maildrop]
 620
 621 ;; LIST [msg]
 622 ;; Arguments: a message-id (optional)
 623 ;; Restrictions: transaction state; msg must not be deleted
 624 ;; Possible responses:
 625 ;;  +OK [scan listing follows]
 626 ;;  -ERR [no such message]
 627
 628 ;; RETR msg
 629 ;; Arguments: a message-id (required)
 630 ;; Restrictions: transaction state; msg must not be deleted
 631 ;; Possible responses:
 632 ;;  +OK [message contents follow]
 633 ;;  -ERR [no such message]
 634
 635 ;; DELE msg
 636 ;; Arguments: a message-id (required)
 637 ;; Restrictions: transaction state; msg must not be deleted
 638 ;; Possible responses:
 639 ;;  +OK [message deleted]
 640 ;;  -ERR [no such message]
 641
 642 ;; NOOP
 643 ;; Arguments: none
 644 ;; Restrictions: transaction state
 645 ;; Possible responses:
 646 ;;  +OK
 647
 648 ;; LAST
 649 ;; Arguments: none
 650 ;; Restrictions: transaction state
 651 ;; Possible responses:
 652 ;;  +OK nn [highest numbered message accessed]
 653
 654 ;; RSET
 655 ;; Arguments: none
 656 ;; Restrictions: transaction state
 657 ;; Possible responses:
 658 ;;  +OK [all delete marks removed]
 659
 660 ;;; UPDATE STATE
 661
 662 ;; QUIT
 663 ;; Arguments: none
 664 ;; Restrictions: none
 665 ;; Possible responses:
 666 ;;  +OK [TCP connection closed]
 667
 668 (provide 'pop3)
 669
 670 ;;; pop3.el ends here