1Net::FTPServer(3) User Contributed Perl Documentation Net::FTPServer(3)
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3
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6 Net::FTPServer - A secure, extensible and configurable Perl FTP server
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9 ftpd.sh [--help] [-d] [-v] [-p port] [-s] [-S] [-V] [-C conf_file]
10 [-P pidfile] [-o option=value]
11
13 "Net::FTPServer" is a secure, extensible and configurable FTP server
14 written in Perl.
15
16 Current features include:
17
18 * Authenticated FTP access.
19 * Anonymous FTP access.
20 * Complete implementation of current RFCs.
21 * ASCII or binary type file transfers.
22 * Active or passive mode file transfers.
23 * Run standalone or from inetd(8).
24 * Security features: chroot, resource limits, tainting,
25 protection against buffer overflows.
26 * IP-based and/or IP-less virtual hosts.
27 * Complete access control system.
28 * Anonymous read-only FTP personality.
29 * Virtual filesystem allows files to be served
30 from a database.
31 * Directory aliases and CDPATH support.
32 * Extensible command set.
33 * Generate archives on the fly.
34
36 A standard "ftpd.conf" file is supplied with the distribution. Full
37 documentation for all the possible options which you may use in this
38 file is contained in this manual page. See the section CONFIGURATION
39 below.
40
41 After doing "make install", the standard "ftpd.conf" file should have
42 been installed in "/etc/ftpd.conf". You will probably need to edit this
43 file to suit your local configuration.
44
45 Also after doing "make install", several start-up scripts will have
46 been installed in "/usr/sbin/*ftpd.pl". (On Debian in "/usr/bin" or
47 "/usr/local/bin"). Each start-up script starts the server in a
48 different configuration: either as a full FTP server, or as an
49 anonymous-only read-only FTP server, etc.
50
51 The commonly used scripts are:
52
53 * /usr/sbin/ftpd.pl
54 * /usr/sbin/ro-ftpd.pl
55
56 The first script is for the full FTP server.
57
58 These scripts assume that the "perl" interpreter can be found on the
59 current $PATH. In the rare situation when this is not the case, you may
60 need to edit these scripts.
61
62 STANDALONE SERVER
63 If you have a high load site, you will want to run "Net::FTPServer" as
64 a standalone server. To start "Net::FTPServer" as a standalone server,
65 do:
66
67 /usr/sbin/ftpd.pl -S
68
69 You may want to add this to your local start-up files so that the
70 server starts automatically when you boot the machine.
71
72 To stop the server, do:
73
74 killall ftpd.pl
75
76 (Note: "Azazel" points out that the above is a Linux-ism. Solaris
77 administrators may get a nasty shock if they type "killall" as "root"!
78 Just kill the parent "ftpd.pl" process by hand instead).
79
80 RUNNING FROM INETD
81 Add the following line to "/etc/inetd.conf":
82
83 ftp stream tcp nowait root /usr/sbin/tcpd ftpd.pl
84
85 (This assumes that you have the "tcp-wrappers" package installed to
86 provide basic access control through "/etc/hosts.allow" and
87 "/etc/hosts.deny". This access control is in addition to any access
88 control which you may configure through "/etc/ftpd.conf".)
89
90 After editing this file you will need to inform "inetd":
91
92 killall -HUP inetd
93
94 RUNNING FROM XINETD
95 "xinetd" is a modern alternative to "inetd" which is supposedly simpler
96 to configure. In practice, however, it has proven to be quite difficult
97 to configure services under "xinetd" (mainly because "xinetd" gives no
98 diagnostic information when things go wrong). The following
99 configuration has worked for me:
100
101 Create the file "/etc/xinetd.d/net-ftpserver" containing:
102
103 # default: on
104 # description: Net::FTPServer, a secure, \
105 # extensible, configurable FTP server.
106 #
107 service ftp
108 {
109 socket_type = stream
110 wait = no
111 user = root
112 server = /usr/sbin/ftpd.pl
113 log_on_success += DURATION USERID
114 log_on_failure += USERID
115 disable = no
116 }
117
118 Check any other possible FTP server configurations to ensure they are
119 all disabled (ie. "disable = yes" in all other files).
120
121 Restart "xinetd" using:
122
123 /etc/init.d/xinetd restart
124
126 --help Display help and exit
127 -d, -v Enable debugging
128 -p PORT Listen on port PORT instead of the default port
129 -s Run in daemon mode (default: run from inetd)
130 -S Run in background and in daemon mode
131 -V Show version information and exit
132 -C CONF Use CONF as configuration file (default:
133 /etc/ftpd.conf)
134 -P PIDFILE Save pid into PIDFILE (daemon mode only)
135 -o option=value Override config file option with value
136 --test Test mode (used only in automatic testing scripts)
137
139 "Net::FTPServer" can be configured and extended in a number of
140 different ways.
141
142 Firstly, almost all common server configuration can be carried out by
143 editing the configuration file "/etc/ftpd.conf".
144
145 Secondly, commands can be loaded into the server at run-time to provide
146 custom extensions to the common FTP command set. These custom commands
147 are written in Perl.
148
149 Thirdly, one of several different supplied personalities can be chosen.
150 Personalities can be used to make deep changes to the FTP server: for
151 example, there is a supplied personality which allows the FTP server to
152 serve files from a relational database. By subclassing
153 "Net::FTPServer", "Net::FTPServer::DirHandle" and
154 "Net::FTPServer::FileHandle" you may also write your own personalities.
155
156 The next sections talk about each of these possibilities in turn.
157
158 CONFIGURATION
159 A standard "/etc/ftpd.conf" file is supplied with "Net::FTPServer" in
160 the distribution. The possible configuration options are listed in full
161 below.
162
163 Simple configuration options can also be given on the command line
164 using the "-o" option. Command line configuration options override
165 those from the configuration file.
166
167 <Include filename>
168 Use the <Include filename> directive to include the contents of
169 "filename" directly at the current point within the configuration
170 file.
171
172 You cannot use <Include> within a <Host> section, or at least you
173 can but it won't work the way you expect.
174
175 <IncludeWildcard wildcard>
176 Include all files matching "wildcard" at this point in the file.
177 The files are included in alphabetical order.
178
179 You cannot use <IncludeWildcard> within a <Host> section, or at
180 least you can but it won't work the way you expect.
181
182 debug
183 Run with debugging. Equivalent to the command line "-d" option.
184
185 Default: 0
186
187 Example: "debug: 1"
188
189 port
190 The TCP port number on which the FTP server listens when running in
191 daemon mode (see "daemon mode" option below).
192
193 Default: The standard ftp/tcp service port from "/etc/services"
194
195 Example: "port: 8021"
196
197 daemon mode
198 Run as a daemon. If set, the FTP server will open a listening
199 socket on its default port number, accept new connections and fork
200 off a new process to handle each connection. If not set (the
201 default), the FTP server will handle a single connection on
202 stdin/stdout, which is suitable for use from inetd.
203
204 The equivalent command line options are "-s" and "-S".
205
206 Default: 0
207
208 Example: "daemon mode: 1"
209
210 run in background
211 Run in the background. If set, the FTP server will fork into the
212 background before running.
213
214 The equivalent command line option is "-S".
215
216 Default: 0
217
218 Example: "run in background: 1"
219
220 error log
221 If set, then all warning and error messages are appended to this
222 file. If not set, warning and error messages get sent to STDERR and
223 to syslog.
224
225 Having an error log is highly recommended.
226
227 Default: (not set, warnings and errors go to syslog)
228
229 Example: "error log: /var/log/ftpd.errors"
230
231 rotate log files
232 If set, and if the log file names contain a '%' directive, then the
233 server will check if a new log file is needed whenever the system
234 accepts a new connection. This implements a log rotation feature
235 for long-running servers.
236
237 If not set, then any '%' directive will be evaluated only when the
238 log files gets created.
239
240 Default: (not set, log file name evaluated only once)
241
242 Example: "rotate log files: 1"
243
244 maintainer email
245 Maintainer's email address.
246
247 Default: root@hostname
248
249 Example: "maintainer email: bob@example.com"
250
251 class
252 Assign users into classes. One or more "class" directives can be
253 added to the configuration file to aggregate individual users into
254 larger groups of users called classes.
255
256 By default all anonymous users are in class "anonymous" and every
257 other user is in class "users".
258
259 The configuration file can contain zero or more "class" directives.
260 The format of the class directive is either:
261
262 class: CLASSNAME USERNAME[,USERNAME[,...]]
263
264 or:
265
266 class: CLASSNAME { perl code ... }
267
268 Examples of the first form are:
269
270 class: staff rich
271 class: students ann,mary,pete
272
273 User "rich" will be placed into class "staff", and users "ann",
274 "mary" and "pete" will be placed into class "students".
275
276 Examples of the second form are:
277
278 class: family { /jones$/ }
279 class: friends { $_ ne "jeff" }
280
281 Any username ending in "jones" (eg. "rjones", "timjones") will be
282 in class "family". Any other user except "jeff" will be placed in
283 class "friends". Note that the Perl code must be surrounded by
284 "{...}" and must return a boolean true or false value. The username
285 is available as $_. The Perl code is arbitrary: it might, for
286 example, use an external file or database lookup in order to work
287 out if a user belongs to a class.
288
289 "class" directives are evaluated in the order in which they appear
290 in the configuration file until one matches the username.
291
292 Default: Anonymous users are assigned to class "anonymous" and
293 everyone else is assigned to class "users".
294
295 timeout
296 Timeout on control connection. If a command has not been received
297 after this many seconds, the server drops the connection. You may
298 set this to zero to disable timeouts completely (although this is
299 not recommended).
300
301 Default: 900 (seconds)
302
303 Example: "timeout: 600"
304
305 limit memory
306 limit nr processes
307 limit nr files
308 Resource limits. These limits are applied to each child process and
309 are important in avoiding denial of service (DoS) attacks against
310 the FTP server.
311
312 Resource Default Unit
313 limit memory 65536 KBytes Amount of memory per child
314 limit nr processes 10 (none) Number of processes
315 limit nr files 20 (none) Number of open files
316
317 To instruct the server not to limit a particular resource, set the
318 limit to "-1".
319
320 Example:
321
322 limit memory: 131072
323 limit nr processes: 20
324 limit nr files: 40
325
326 limit nr processes: -1
327
328 max clients
329 Limit on the number of clients who can simultaneously connect. If
330 this limit is ever reached, new clients will immediately be closed.
331 It will not even ask the client to login. This feature works in
332 daemon mode only.
333
334 Default: 255
335
336 Example: "max clients: 600"
337
338 max clients message
339 Message to display when ``max clients'' has been reached.
340
341 You may use the following % escape sequences within the message for
342 internal variables:
343
344 %x ``max clients'' setting that has been reached
345 %E maintainer email address (from ``maintainer email''
346 setting above)
347 %G time in GMT
348 %R remote hostname or IP address if ``resolve addresses''
349 is not set
350 %L local hostname
351 %T local time
352 %% just an ordinary ``%''
353
354 Default: Maximum connections reached
355
356 Example: "max clients message: Only %x simultaneous connections
357 allowed. Please try again later."
358
359 resolve addresses
360 Resolve addresses. If set, attempt to do a reverse lookup on client
361 addresses for logging purposes. If you set this then some clients
362 may experience long delays when they try to connect. Not
363 recommended on high load servers.
364
365 Default: 0
366
367 Example: "resolve addresses: 1"
368
369 require resolved addresses
370 Require resolved addresses. If set, client addresses must validly
371 resolve otherwise clients will not be able to connect. If you set
372 this then some clients will not be able to connect, even though it
373 is probably the fault of their ISP.
374
375 Default: 0
376
377 Example: "require resolved addresses: 1"
378
379 change process name
380 Change process name. If set (the default) then the FTP server will
381 change its process name to reflect the IP address or hostname of
382 the client. If not set then the FTP server will not try to change
383 its process name.
384
385 Default: 1
386
387 Example: "change process name: 0"
388
389 greeting type
390 Greeting type. The greeting is printed before the user has logged
391 in. Possible greeting types are:
392
393 full Full greeting, including hostname and version number.
394 brief Hostname only.
395 terse Nothing
396 text Display greeting from ``greeting text'' option.
397
398 The SITE VERSION command can also reveal the version number. You
399 may need to turn this off by setting "allow site version command:
400 0" below.
401
402 Default: full
403
404 Example: "greeting type: text"
405
406 greeting text
407 Greeting text. If the "greeting type" is set to "text" then this
408 contains the text to display.
409
410 Default: none
411
412 Example: "greeting text: Hello. I'll be your server today."
413
414 welcome type
415 Welcome type. The welcome is printed after a user has logged in.
416 Possible welcome types are:
417
418 normal Normal welcome message: ``Welcome <<username>>.''
419 text Take the welcome message from ``welcome text'' option.
420 file Take the welcome message from ``welcome file'' file.
421
422 Default: normal
423
424 Example: "welcome type: text"
425
426 welcome text
427 If "welcome type" is set to "text", then this contains the text to
428 be printed after a user has logged in.
429
430 You may use the following % escape sequences within the welcome
431 text to substitute for internal variables:
432
433 %E maintainer's email address (from ``maintainer email''
434 setting above)
435 %G time in GMT
436 %R remote hostname or IP address if ``resolve addresses''
437 is not set
438 %L local hostname
439 %m user's home directory (see ``home directory'' below)
440 %T local time
441 %U username given when logging in
442 %u currently a synonym for %U, but in future will be
443 determined from RFC931 authentication, like wu-ftpd
444 %% just an ordinary ``%''
445
446 Default: none
447
448 Example: "welcome text: Welcome to this FTP server."
449
450 welcome file
451 If "welcome type" is set to "file", then this contains the file to
452 be printed after a user has logged in.
453
454 You may use any of the % escape sequences defined in "welcome text"
455 above.
456
457 Default: none
458
459 Example: "welcome file: /etc/motd"
460
461 home directory
462 Home directory. This is the home directory where we put the user
463 once they have logged in. This only applies to non-anonymous
464 logins. Anonymous logins are always placed in "/", which is at the
465 root of their chrooted environment.
466
467 You may use an absolute path here, or else one of the following
468 special forms:
469
470 %m Use home directory from password file or from NSS.
471 %U Username.
472 %% A single % character.
473
474 For example, to force a user to start in "~/anon-ftp" when they log
475 in, set this to "%m/anon-ftp".
476
477 Note that setting the home directory does not perform a chroot.
478 Use the "root directory" setting below to jail users into a
479 particular directory.
480
481 Home directories are relative to the current root directory.
482
483 In the anonymous read-only (ro-ftpd) personality, set home
484 directory to "/" or else you will get a warning whenever a user
485 logs in.
486
487 Default: %m
488
489 Examples:
490
491 home directory: %m/anon-ftp
492 home directory: /
493
494 root directory
495 Root directory. Immediately after logging in, perform a chroot into
496 the named directory. This only applies to non-anonymous logins, and
497 furthermore it only applies if you have a non-database VFS
498 installed. Database VFSes typically cannot perform chroot (or, to
499 be more accurate, they have a different concept of chroot -
500 typically assigning each user their own completely separate
501 namespace).
502
503 You may use %m and %U as above.
504
505 For example, to jail a user under "~/anon-ftp" after login, do:
506
507 home directory: /
508 root directory: %m/anon-ftp
509
510 Notice that the home directory is relative to the current root
511 directory.
512
513 Default: (none)
514
515 Example: "root directory: %m/anon-ftp"
516
517 time zone
518 Time zone to be used for MDTM and LIST stat information.
519
520 Default: GMT
521
522 Examples:
523
524 time zone: Etc/GMT+3
525 time zone: Europe/London
526 time zone: US/Mountain
527
528 local address
529 Local addresses. If you wish the FTP server (in daemon mode) to
530 only bind to a particular local interface, then give its address
531 here.
532
533 Default: none
534
535 Example: "local address: 127.0.0.1"
536
537 allow anonymous
538 Allow anonymous access. If set, then allow anonymous access through
539 the "ftp" and "anonymous" accounts.
540
541 Default: 0
542
543 Example: "allow anonymous: 1"
544
545 anonymous password check
546 anonymous password enforce
547 Validate email addresses. Normally when logging in anonymously, you
548 are asked to enter your email address as a password. These options
549 can be used to check and enforce email addresses in this field (to
550 some extent, at least -- you obviously can't force someone to enter
551 a true email address).
552
553 The "anonymous password check" option may be set to "rfc822", "no
554 browser", "trivial" or "none". If set to "rfc822" then the user
555 must enter a valid RFC 822 email address as password. If set to "no
556 browser" then a valid RFC 822 email address must be entered, and
557 various common browser email addresses like "mozilla@" and
558 "IEverUser@" are refused. If set to "trivial" then we just check
559 that the address contains an @ char. If set to "none", then we do
560 no checking. The default is "none".
561
562 If the "anonymous password enforce" option is set and the password
563 fails the check above, then the user will not be allowed to log in.
564 The default is 0 (unset).
565
566 These options only have effect when "allow anonymous" is set.
567
568 Example:
569
570 anonymous password check: rfc822
571 anonymous password enforce: 1
572
573 allow proxy ftp
574 Allow proxy FTP. If this is set, then the FTP server can be told to
575 actively connect to addresses and ports on any machine in the
576 world. This is not such a great idea, but required if you follow
577 the RFC very closely. If not set (the default), the FTP server will
578 only connect back to the client machine.
579
580 Default: 0
581
582 Example: "allow proxy ftp: 1"
583
584 allow connect low port
585 Allow the FTP server to connect back to ports < 1024. This is
586 rarely useful and could pose a serious security hole in some
587 circumstances.
588
589 Default: 0
590
591 Example: "allow connect low port: 1"
592
593 passive port range
594 What range of local ports will the FTP server listen on in passive
595 mode? Choose a range here like "1024-5999,49152-65535". The special
596 value 0 means that the FTP server will use a kernel-assigned
597 ephemeral port.
598
599 Default: 49152-65535
600
601 Example: "passive port range: 0"
602
603 ftp data port
604 Which source port to use for active (non-passive) mode when
605 connecting to the client for PORT mode transfers. The special
606 value 0 means that the FTP server will use a kernel-assigned
607 ephemeral port. To strictly follow RFC, this should be set to
608 "ftp-data(20)". This may be required for certain brain-damaged
609 firewall configurations. However, for security reasons, the
610 default setting is intentionally set to 0 to utilize a kernel-
611 assigned ephemeral port. Use this directive at your own risk!
612
613 SECURITY PRECAUTIONS:
614
615 1) Unfortunately, to use a port < 1024 requires super-user
616 privileges. Thus, low ports will not work unless the FTP server is
617 invoked as super-user. This also implies that all processes
618 handling the client connections must also remain super-user
619 throughout the entire session. It is highly discouraged to use a
620 low port.
621
622 http://cr.yp.to/ftp/security.html
623 (See "Connection laundering" section)
624
625 2) There sometimes exists a danger of needing to connect to the
626 same remote host:port. Using the same IP/port on both sides will
627 cause connect() to fail if the old socket is still being broken
628 down. This condition will not occur if using an ephemeral port.
629
630 http://groups.google.com/groups?selm=fa.epucqgv.1l2kl0e@ifi.uio.no
631 (See "unable to create socket" comment)
632
633 3) Many hackers use source port 20 to blindly circumvent certain
634 naive firewalls. Using an ephemeral port (the default) may help
635 discourage such dangerous naivety.
636
637 man nmap
638 (See the -g option)
639
640 Default: 0
641
642 Example: "ftp data port: ftp-data"
643
644 max login attempts
645 Maximum number of login attempts before we drop the connection and
646 issue a warning in the logs. Wu-ftpd defaults this to 5.
647
648 Default: 3
649
650 Example: "max login attempts: 5"
651
652 pam authentication
653 Use PAM for authentication. Required on systems such as Red Hat
654 Linux and Solaris which use PAM for authentication rather than the
655 normal "/etc/passwd" mechanisms. You will need to have the
656 "Authen::PAM" Perl module installed for this to work.
657
658 Default: 0
659
660 Example: "pam authentication: 1"
661
662 pam application name
663 If PAM authentication is enabled, then this is the PAM application
664 name. I have used "ftp" as the default which is the same name that
665 wu-ftpd chooses. FreeBSD users will want to use "ftpd" here.
666
667 Default: ftp
668
669 Example: "pam application name: ftpd"
670
671 password file
672 Only in the "Full" personality, this allows you to specify a
673 password file which is used for authentication. If you enable this
674 option, then normal PAM or "/etc/passwd" is bypassed and this
675 password file is used instead.
676
677 Each line in the password file has the following format:
678
679 username:crypted_password:unix_user[:root_directory]
680
681 Comments and blank lines are ignored.
682
683 For example, a line with:
684
685 guest:ab01FAX.bQRSU:rich:/home/rich/guest-uploads
686
687 would allow someone to log in as "guest" with password 123456.
688 After logging in, the FTP server will assume the identity of the
689 real Unix user "rich", and will chroot itself into the
690 "/home/rich/guest-uploads" directory.
691
692 (Note that because ordinary PAM/"passwd" is bypassed, it would no
693 longer be possible for a user to log in directly with the username
694 "rich").
695
696 Crypted passwords can be generated using the following command:
697
698 perl -e 'print crypt ("123456", "ab"), "\n"'
699
700 Replace 123456 with the actual password, and replace "ab" with two
701 random letters from the set "[a-zA-Z0-9./]". (The two random
702 letters are the so-called salt and are used to make dictionary
703 attacks against the password file more difficult - see crypt(3)).
704
705 The user's home directory comes from the real Unix password file
706 (or nsswitch-configured source) for the real Unix user. You cannot
707 use password files to override this, and so if you are using the
708 optional "root_directory" parameter, it would make sense to add
709 "home directory: /" into your configuration file.
710
711 Anonymous logins are not affected by the "password file" option.
712 Use the "allow anonymous" flag to control whether anonymous logins
713 are permitted in the "Full" back-end.
714
715 Password files are not the height of security, but they are
716 included because they can sometimes be useful. In particular if the
717 password file can be read by untrusted users then it is likely that
718 those same users can run the crack program and eventually find out
719 your passwords. Some small additional security is offered by having
720 the password file readable only by root (mode 0600). In future we
721 may offer MD5 or salted SHA-1 hashed passwords to make this harder.
722
723 A curious artifact of the implementation allows you to list the
724 same user with multiple different passwords. Any of the passwords
725 is then valid for logins (and you could even have the user map to
726 different real Unix users in different chrooted directories!)
727
728 Default: (none)
729
730 Example: "password file: /etc/ftpd.passwd"
731
732 pidfile
733 Location of the file to store the process ID (PID). Applies only
734 to the deamonized process, not the child processes.
735
736 Default: (no pidfile created)
737
738 Example: "pidfile: /var/run/ftpd.pid"
739
740 client logging
741 Location to store all client commands sent to the server. The
742 format is the date, the pid, and the command. Following the pid is
743 a "-" if not authenticated the username if the connection is
744 authenticated. Example of before and after authentication:
745
746 [Wed Feb 21 18:41:32 2001][23818:-]USER rob
747 [Wed Feb 21 18:41:33 2001][23818:-]PASS 123456
748 [Wed Feb 21 18:41:33 2001][23818:*]SYST
749
750 Default: (no logging)
751
752 Examples:
753
754 client logging: /var/log/ftpd.log
755 client logging: /tmp/ftpd_log.$hostname
756
757 xfer logging
758 Location of transfer log. The format was taken from wu-ftpd and
759 ProFTPD xferlog. (See also "man xferlog")
760
761 Default: (no logging)
762
763 Examples:
764
765 xfer logging: /var/log/xferlog
766 xfer logging: /tmp/xferlog.$hostname
767
768 hide passwords in client log
769 If set to 1, then password ("PASS") commands will not be logged in
770 the client log. This option has no effect unless client logging is
771 enabled.
772
773 Default: 0 (PASS lines will be shown)
774
775 Example: "hide passwords in client log: 1"
776
777 enable syslog
778 Enable syslogging. If set, then Net::FTPServer will send much
779 information to syslog. On many systems, this information will be
780 available in /var/log/messages or /var/adm/messages. If clear,
781 syslogging is disabled.
782
783 Default: 1
784
785 Example: "enable syslog: 0"
786
787 ident timeout
788 Timeout for ident authentication lookups. A timeout (in seconds)
789 must be specified in order to enable ident lookups. There is no
790 way to specify an infinite timeout. Use 0 to disable this feature.
791
792 Default: 0
793
794 Example: "ident timeout: 10"
795
796 access control rule
797 user access control rule
798 retrieve rule
799 store rule
800 delete rule
801 list rule
802 mkdir rule
803 rename rule
804 chdir rule
805 Access control rules.
806
807 Access control rules are all specified as short snippets of Perl
808 script. This allows the maximum configurability -- you can express
809 just about any rules you want -- but at the price of learning a
810 little Perl.
811
812 You can use the following variables from the Perl:
813
814 $hostname Resolved hostname of the client [1]
815 $ip IP address of the client
816 $user User name [2]
817 $class Class of user [2]
818 $user_is_anonymous True if the user is an anonymous user [2]
819 $pathname Full pathname of the file being affected [2]
820 $filename Filename of the file being affected [2,3]
821 $dirname Directory name containing file being affected [2]
822 $type 'A' for ASCII, 'B' for binary, 'L8' for local 8-bit
823 $form Always 'N'
824 $mode Always 'S'
825 $stru Always 'F'
826
827 Notes:
828
829 [1] May be undefined, particularly if "resolve addresses" is not
830 set.
831
832 [2] Not available in "access control rule" since the user has not
833 logged in at this point.
834
835 [3] Not available for "list directory rule".
836
837 Access control rule. The FTP server will not accept any connections
838 from a site unless this rule succeeds. Note that only $hostname and
839 $ip are available to this rule, and unless "resolve addresses" and
840 "require resolved addresses" are both set $hostname may be
841 undefined.
842
843 Default: 1
844
845 Examples:
846
847 (a) Deny connections from *.badguys.com:
848
849 access control rule: defined ($hostname) && \
850 $hostname !~ /\.badguys\.com$/
851
852 (b) Only allow connections from local network 10.0.0.0/24:
853
854 access control rule: $ip =~ /^10\./
855
856 User access control rule. After the user logs in successfully, this
857 rule is then called to determine if the user may be permitted
858 access.
859
860 Default: 1
861
862 Examples:
863
864 (a) Only allow ``rich'' to log in from 10.x.x.x network:
865
866 user access control rule: $user ne "rich" || \
867 $ip =~ /^10\./
868
869 (b) Only allow anonymous users to log in if they come from
870 hosts with resolving hostnames (``resolve addresses'' must
871 also be set):
872
873 user access control rule: !$user_is_anonymous || \
874 defined ($hostname)
875
876 (c) Do not allow user ``jeff'' to log in at all:
877
878 user access control rule: $user ne "jeff"
879
880 Retrieve rule. This rule controls who may retrieve (download)
881 files.
882
883 Default: 1
884
885 Examples:
886
887 (a) Do not allow anyone to retrieve ``/etc/*'' or any file anywhere
888 called ``.htaccess'':
889
890 retrieve rule: $dirname !~ m(^/etc/) && $filename ne ".htaccess"
891
892 (b) Only allow anonymous users to retrieve files from under the
893 ``/pub'' directory.
894
895 retrieve rule: !$user_is_anonymous || $dirname =~ m(^/pub/)
896
897 Store rule. This rule controls who may store (upload) files.
898
899 In the anonymous read-only (ro-ftpd) personality, it is not
900 possible to upload files anyway, so setting this rule has no
901 effect.
902
903 Default: 1
904
905 Examples:
906
907 (a) Only allow users to upload files to the ``/incoming''
908 directory.
909
910 store rule: $dirname =~ m(^/incoming/)
911
912 (b) Anonymous users can only upload files to ``/incoming''
913 directory.
914
915 store rule: !$user_is_anonymous || $dirname =~ m(^/incoming/)
916
917 (c) Disable file upload.
918
919 store rule: 0
920
921 Delete rule. This rule controls who may delete files or rmdir
922 directories.
923
924 In the anonymous read-only (ro-ftpd) personality, it is not
925 possible to delete files anyway, so setting this rule has no
926 effect.
927
928 Default: 1
929
930 Example: "delete rule: 0"
931
932 List rule. This rule controls who may list out the contents of a
933 directory.
934
935 Default: 1
936
937 Example: "list rule: $dirname =~ m(^/pub/)"
938
939 Mkdir rule. This rule controls who may create a subdirectory.
940
941 In the anonymous read-only (ro-ftpd) personality, it is not
942 possible to create directories anyway, so setting this rule has no
943 effect.
944
945 Default: 1
946
947 Example: "mkdir rule: 0"
948
949 Rename rule. This rule controls which files or directories can be
950 renamed.
951
952 Default: 1
953
954 Example: "rename rule: $pathname !~ m(/.htaccess$)"
955
956 Chdir rule. This rule controls which directories are acceptable to
957 a CWD or CDUP.
958
959 Example: "chdir rule: $pathname !~ m/private/"
960
961 chdir message file
962 Change directory message file. If set, then the first time (per
963 session) that a user goes into a directory which contains a file
964 matching this name, that file will be displayed.
965
966 The file may contain any of the following % escape sequences:
967
968 %C current working directory
969 %E maintainer's email address (from ``maintainer email''
970 setting above)
971 %G time in GMT
972 %R remote hostname or IP address if ``resolve addresses''
973 is not set
974 %L local hostname
975 %m user's home directory (see ``home directory'' below)
976 %T local time
977 %U username given when logging in
978 %u currently a synonym for %U, but in future will be
979 determined from RFC931 authentication, like wu-ftpd
980 %% just an ordinary ``%''
981
982 Default: (none)
983
984 Example: "chdir message file: .message"
985
986 allow rename to overwrite
987 Allow the rename (RNFR/RNTO) command to overwrite files. If unset,
988 then we try to test whether the rename command would overwrite a
989 file and disallow it. However there are some race conditions with
990 this test.
991
992 Default: 1
993
994 Example: "allow rename to overwrite: 0"
995
996 allow store to overwrite
997 Allow the store commands (STOR/STOU/APPE) to overwrite files. If
998 unset, then we try to test whether the store command would
999 overwrite a file and disallow it. However there are some race
1000 conditions with this test.
1001
1002 Default: 1
1003
1004 Example: "allow store to overwrite: 0"
1005
1006 alias
1007 Define an alias "name" for directory "dir". For example, the
1008 command "alias: mirror /pub/mirror" would allow the user to access
1009 the "/pub/mirror" directory directly just by typing "cd mirror".
1010
1011 Aliases only apply to the cd (CWD) command. The "cd foo" command
1012 checks for directories in the following order:
1013
1014 foo in the current directory
1015 an alias called foo
1016 foo in each directory in the cdpath (see ``cdpath'' command below)
1017
1018 You may list an many aliases as you want.
1019
1020 Alias names cannot contain slashes (/).
1021
1022 Although alias dirs may start without a slash (/), this is unwise
1023 and it's better that they always start with a slash (/) char.
1024
1025 General format: "alias: name dir"
1026
1027 cdpath
1028 Define a search path which is used when changing directories. For
1029 example, the command "cdpath: /pub/mirror /pub/sites" would allow
1030 the user to access the "/pub/mirror/ftp.cpan.org" directory
1031 directly by just typing "cd ftp.cpan.org".
1032
1033 The "cd foo" command checks for directories in the following order:
1034
1035 foo in the current directory
1036 an alias called foo (see ``alias'' command above)
1037 foo in each directory in the cdpath
1038
1039 General format: "cdpath: dir1 [dir2 [dir3 ...]]"
1040
1041 allow site version command
1042 SITE VERSION command. If set, then the SITE VERSION command reveals
1043 the current Net::FTPServer version string. If unset, then the
1044 command is disabled.
1045
1046 Default: 1
1047
1048 Example: "allow site version command: 0"
1049
1050 allow site exec command
1051 SITE EXEC command. If set, then the SITE EXEC command allows
1052 arbitrary commands to be executed on the server as the current
1053 user. If unset, then this command is disabled. The default is
1054 disabled for obvious security reasons.
1055
1056 If you do allow SITE EXEC, you may need to increase the per process
1057 memory, processes and files limits above.
1058
1059 Default: 0
1060
1061 Example: "allow site exec command: 1"
1062
1063 enable archive mode
1064 Archive mode. If set (the default), then archive mode is enabled,
1065 allowing users to request, say, "file.gz" and get a version of
1066 "file" which is gzip-compressed on the fly. If zero, then this
1067 feature is disabled. See the section ARCHIVE MODE elsewhere in this
1068 manual for details.
1069
1070 Since archive mode is implemented using external commands, you need
1071 to ensure that programs such as "gzip", "compress", "bzip2",
1072 "uuencode", etc. are available on the $PATH (even in the chrooted
1073 environment), and you also need to substantially increase the
1074 normal per-process memory, processes and files limits.
1075
1076 Default: 1
1077
1078 Example: "enable archive mode: 0"
1079
1080 archive zip temporaries
1081 Temporary directory for generating ZIP files in archive mode. In
1082 archive mode, when generating ZIP files, the FTP server is capable
1083 of either creating a temporary file on local disk containing the
1084 ZIP contents, or can generate the file completely in memory. The
1085 former method saves memory. The latter method (only practical on
1086 small ZIP files) allows the server to work more securely and in
1087 certain read-only chrooted environments.
1088
1089 (Unfortunately the ZIP file format itself prevents ZIP files from
1090 being easily created on the fly).
1091
1092 If not specified in the configuration file, this option defaults to
1093 using "/tmp". If there are local users on the FTP server box, then
1094 this can lead to various "tmp" races, so for maximum security you
1095 will probably want to change this.
1096
1097 If specified, and set to a string, then the string is the name of a
1098 directory which is used for storing temporary zip files. This
1099 directory must be writable, and must exist inside the chrooted
1100 environment (if chroot is being used).
1101
1102 If specified, but set to "0" or an empty string, then the server
1103 will always generate the ZIP file in memory.
1104
1105 In any case, if the directory is found at runtime to be unwritable,
1106 then the server falls back to creating ZIP files in memory.
1107
1108 Default: "/tmp"
1109
1110 Example: "archive zip temporaries: "
1111
1112 Example: "archive zip temporaries: /var/ziptmp"
1113
1114 site command
1115 Custom SITE commands. Use this command to define custom SITE
1116 commands. Please read the section LOADING CUSTOMIZED SITE COMMANDS
1117 in this manual page for more detailed information.
1118
1119 The "site command" command has the form:
1120
1121 "site command: cmdname file"
1122
1123 cmdname is the name of the command (eg. for SITE README you would
1124 set cmdname == "readme"). file is a file containing the code of the
1125 site command in the form of an anonymous Perl subroutine. The file
1126 should have the form:
1127
1128 sub {
1129 my $self = shift; # The FTPServer object.
1130 my $cmd = shift; # Contains the command itself.
1131 my $rest = shift; # Contains any parameters passed by the user.
1132
1133 : :
1134 : :
1135
1136 $self->reply (RESPONSE_CODE, RESPONSE_TEXT);
1137 }
1138
1139 You may define as many site commands as you want. You may also
1140 override site commands from the current personality here.
1141
1142 Example:
1143
1144 site command: quota /usr/local/lib/ftp/quota.pl
1145
1146 and the file "/usr/local/lib/ftp/quota.pl" contains:
1147
1148 sub {
1149 my $self = shift; # The FTPServer object.
1150 my $cmd = shift; # Contains "QUOTA".
1151 my $rest = shift; # Contains parameters passed by user.
1152
1153 # ... Some code to compute the user's quota ...
1154
1155 $self->reply (200, "Your quota is $quota MB.");
1156 }
1157
1158 The client types "SITE QUOTA" and the server responds with:
1159
1160 "200 Your quota is 12.5 MB.".
1161
1162 <Host hostname> ... </Host>
1163 <Host hostname> ... </Host> encloses commands which are applicable
1164 only to a particular host. "hostname" may be either a fully-
1165 qualified domain name (for IP-less virtual hosts) or an IP address
1166 (for IP-based virtual hosts). You should read the section VIRTUAL
1167 HOSTS in this manual page for more information on the different
1168 types of virtual hosts and how to set it up in more detail.
1169
1170 Note also that unless you have set "enable virtual hosts: 1", all
1171 <Host> sections will be ignored.
1172
1173 enable virtual hosts
1174 Unless this option is uncommented, virtual hosting is disabled and
1175 the <Host> sections in the configuration file have no effect.
1176
1177 Default: 0
1178
1179 Example: "enable virtual hosts: 1"
1180
1181 virtual host multiplex
1182 IP-less virtual hosts. If you want to enable IP-less virtual hosts,
1183 then you must set up your DNS so that all hosts map to a single IP
1184 address, and place that IP address here. This is roughly equivalent
1185 to the Apache "NameVirtualHost" option.
1186
1187 IP-less virtual hosting is an experimental feature which requires
1188 changes to clients.
1189
1190 Default: (none)
1191
1192 Example: "virtual host multiplex: 1.2.3.4"
1193
1194 Example <Host> section. Allow the dangerous SITE EXEC command on
1195 local connections. (Note that this is still dangerous).
1196
1197 <Host localhost.localdomain>
1198 ip: 127.0.0.1
1199 allow site exec command: 1
1200 </Host>
1201
1202 Example <Host> section. This shows you how to do IP-based virtual
1203 hosts. I assume that you have set up your DNS so that
1204 "ftp.bob.example.com" maps to IP 1.2.3.4 and "ftp.jane.example.com"
1205 maps to IP 1.2.3.5, and you have set up suitable IP aliasing in the
1206 kernel.
1207
1208 You do not need the "ip:" command if you have configured reverse
1209 DNS correctly AND you trust your local DNS servers.
1210
1211 <Host ftp.bob.example.com>
1212 ip: 1.2.3.4
1213 root directory: /home/bob
1214 home directory: /
1215 user access control rule: $user eq "bob"
1216 maintainer email: bob@bob.example.com
1217 </Host>
1218
1219 <Host ftp.jane.example.com>
1220 ip: 1.2.3.5
1221 root directory: /home/jane
1222 home directory: /
1223 allow anonymous: 1
1224 user access control rule: $user_is_anonymous
1225 maintainer email: jane@jane.example.com
1226 </Host>
1227
1228 These rules set up two virtual hosts called "ftp.bob.example.com"
1229 and "ftp.jane.example.com". The former is located under bob's home
1230 directory and only he is allowed to log in. The latter is located
1231 under jane's home directory and only allows anonymous access.
1232
1233 Example <Host> section. This shows you how to do IP-less virtual
1234 hosts. Note that IP-less virtual hosts are a highly experimental
1235 feature, and require the client to support the HOST command.
1236
1237 You need to set up your DNS so that both "ftp.bob.example.com" and
1238 "ftp.jane.example.com" point to your own IP address.
1239
1240 virtual host multiplex: 1.2.3.4
1241
1242 <Host ftp.bob.example.com>
1243 root directory: /home/bob
1244 home directory: /
1245 user access control rule: $user eq "bob"
1246 </Host>
1247
1248 <Host ftp.jane.example.com>
1249 root directory: /home/jane
1250 home directory: /
1251 allow anonymous: 1
1252 user access control rule: $user_is_anonymous
1253 </Host>
1254
1255 log socket type
1256 Socket type for contacting syslog. This is the argument to the
1257 "Sys::Syslog::setlogsock" function.
1258
1259 Default: unix
1260
1261 Example: "log socket type: inet"
1262
1263 listen queue
1264 Length of the listen queue when running in daemon mode.
1265
1266 Default: 10
1267
1268 Example: "listen queue: 20"
1269
1270 tcp window
1271 Set TCP window. See RFC 2415 Simulation Studies of Increased
1272 Initial TCP Window Size. This setting only affects the data
1273 socket. It's not likely that you will need to or should change this
1274 setting from the system-specific default.
1275
1276 Default: (system-specific TCP window size)
1277
1278 Example: "tcp window: 4380"
1279
1280 tcp keepalive
1281 Set TCP keepalive.
1282
1283 Default: (system-specific keepalive setting)
1284
1285 Example: "tcp keepalive: 1"
1286
1287 command filter
1288 Command filter. If set, then all commands are checked against this
1289 regular expression before being executed. If a command doesn't
1290 match the filter, then the command connection is immediately
1291 dropped. This is equivalent to the "AllowFilter" command in
1292 ProFTPD. Remember to include "^...$" around the filter.
1293
1294 Default: (no filter)
1295
1296 Example: "command filter: ^[A-Za-z0-9 /]+$"
1297
1298 restrict command
1299 Advanced command filtering. The "restrict command" directive takes
1300 the form:
1301
1302 restrict command: "COMMAND" perl code ...
1303
1304 If the user tries to execute "COMMAND", then the "perl code" is
1305 evaluated first. If it evaluates to true, then the command is
1306 allowed to proceed. Otherwise the server reports an error back to
1307 the user and does not execute the command.
1308
1309 Note that the "COMMAND" is the FTP protocol command, which is not
1310 necessarily the same as the command which users will type in on
1311 their FTP clients. Please read RFC 959 to see some of the more
1312 common FTP protocol commands.
1313
1314 The Perl code has the same variables available to it as for access
1315 control rules (eg. $user, $class, $ip, etc.). The code must not
1316 alter the global $_ variable (which contains the complete command).
1317
1318 Default: all commands are allowed by default
1319
1320 Examples:
1321
1322 Only allow users in the class "nukers" to delete files and
1323 directories:
1324
1325 restrict command: "DELE" $class eq "nukers"
1326 restrict command: "RMD" $class eq "nukers"
1327
1328 Only allow staff to use the "SITE WHO" command:
1329
1330 restrict command: "SITE WHO" $class eq "staff"
1331
1332 Only allow "rich" to run the "SITE EXEC" command:
1333
1334 allow site exec command: 1
1335 restrict command: "SITE EXEC" $user eq "rich"
1336
1337 command wait
1338 Go slow. If set, then the server will sleep for this many seconds
1339 before beginning to process each command. This command would be a
1340 lot more useful if you could apply it only to particular classes of
1341 connection.
1342
1343 Default: (no wait)
1344
1345 Example: "command wait: 5"
1346
1347 no authentication commands
1348 The list of commands which a client may issue before they have
1349 authenticated themselves is very limited. Obviously "USER" and
1350 "PASS" are allowed (otherwise a user would never be able to log
1351 in!), also "QUIT", "LANG", "HOST" and "FEAT". "HELP" is also
1352 permitted (although dubious). Any other commands not on this list
1353 will result in a 530 Not logged in. error.
1354
1355 This list ought to contain at least "USER", "PASS" and "QUIT"
1356 otherwise the server won't be very functional.
1357
1358 Some commands cannot be added here -- eg. adding "CWD" or "RETR" to
1359 this list is likely to make the FTP server crash, or else enable
1360 users to read files only available to root. Hence use this with
1361 great care.
1362
1363 Default: USER PASS QUIT LANG HOST FEAT HELP
1364
1365 Example: "no authentication commands: USER PASS QUIT"
1366
1367 <Perl> ... </Perl>
1368 Use the <Perl> directive to write Perl code directly into your
1369 configuration file. Here is a simple example:
1370
1371 <Perl>
1372 use Sys::Hostname;
1373 $config{'maintainer email'} = "root\@" . hostname ();
1374 $config{port} = 8000 + 21;
1375 $config{debug} = $ENV{FTP_DEBUG} ? 1 : 0;
1376 </Perl>
1377
1378 As shown in the example, to set a configuration option called
1379 "foo", you simply assign to the variable $config{foo}.
1380
1381 All normal Perl functionality is available to you, including use of
1382 "require" if you need to run an external Perl script.
1383
1384 The <Perl> and </Perl> directives must each appear on a single line
1385 on their own.
1386
1387 To assign multiple configuration options with the same name, use an
1388 array ref:
1389
1390 <Perl>
1391 my @aliases = ( "foo /pub/foo",
1392 "bar /pub/bar",
1393 "baz /pub/baz" );
1394 $config{alias} = \@aliases;
1395 </Perl>
1396
1397 You cannot use a <Perl> section within a <Host> section. Instead,
1398 you must simulate it by assigning to the %host_config variable like
1399 this:
1400
1401 <Perl>
1402 $host_config{'localhost.localdomain'}{ip} = "127.0.0.1";
1403 $host_config{'localhost.localdomain'}{'allow site exec command'}= 1;
1404 </Perl>
1405
1406 The above is equivalent to the following ordinary <Host> section:
1407
1408 <Host localhost.localdomain>
1409 ip: 127.0.0.1
1410 allow site exec command: 1
1411 </Host>
1412
1413 You may also assign to the $self variable in order to set variables
1414 directly in the "Net::FTPServer" object itself. This is pretty
1415 hairy, and hence not recommended, but you dig your own hole if you
1416 want. Here is a contrived example:
1417
1418 <Perl>
1419 $self->{version_string} = "my FTP server/1.0";
1420 </Perl>
1421
1422 A cleaner, but more complex way to do this would be to use a
1423 personality.
1424
1425 The <Perl> directive is potentially quite powerful. Here is a good
1426 idea that Rob Brown had:
1427
1428 <Perl>
1429 my %H;
1430 dbmopen (%H, "/etc/ftpd.db", 0644);
1431 %config = %H;
1432 dbmclose (%H);
1433 </Perl>
1434
1435 Notice how this allows you to crunch a possibly very large
1436 configuration file into a hash, for very rapid loading at run time.
1437
1438 Another useful way to use <Perl> is to set environment variables
1439 (particularly $PATH).
1440
1441 <Perl>
1442 $ENV{PATH} = "/usr/local/bin:$ENV{PATH}"
1443 </Perl>
1444
1445 Here's yet another wonderful way to use <Perl>. Look in
1446 "/usr/local/lib/ftp/" for a list of site commands and load each
1447 one:
1448
1449 <Perl>
1450
1451 my @files = glob "/usr/local/lib/ftp/*.pl";
1452 my @site_commands;
1453
1454 foreach (@files)
1455 {
1456 push @site_commands, "$1 $_" if /([a-z]+)\.pl/;
1457 }
1458
1459 $config{'site command'} = \@site_commands;
1460
1461 </Perl>
1462
1463 To force a particular version of Net::FTPServer to be used, include
1464 the following code in your configuration file:
1465
1466 <Perl>
1467 die "requires Net::FTPServer version >= 1.025"
1468 unless $Net::FTPServer::VERSION !~ /\..*\./ &&
1469 $Net::FTPServer::VERSION >= 1.025;
1470 </Perl>
1471
1472 LOADING CUSTOMIZED SITE COMMANDS
1473 It is very simple to write custom SITE commands. These commands are
1474 available to users when they type "SITE XYZ" in a command line FTP
1475 client or when they define a custom SITE command in their graphical FTP
1476 client.
1477
1478 SITE commands are unregulated by RFCs. You may define any commands and
1479 give them any names and any function you wish. However, over time
1480 various standard SITE commands have been recognized and implemented in
1481 many FTP servers. "Net::FTPServer" also implements these. They are:
1482
1483 SITE VERSION Display the server software version.
1484 SITE EXEC Execute a shell command on the server (in
1485 C<Net::FTPServer> this is disabled by default!)
1486 SITE ALIAS Display chdir aliases.
1487 SITE CDPATH Display chdir paths.
1488 SITE CHECKMETHOD Implement checksums.
1489 SITE CHECKSUM
1490 SITE IDLE Get or set the idle timeout.
1491 SITE SYNC Synchronize hard disks.
1492
1493 The following commands are found in "wu-ftpd", but not currently
1494 implemented by "Net::FTPServer": SITE CHMOD, SITE GPASS, SITE GROUP,
1495 SITE GROUPS, SITE INDEX, SITE MINFO, SITE NEWER, SITE UMASK.
1496
1497 So when you are choosing a name for a SITE command, it is probably best
1498 not to choose one of the above names, unless you are specifically
1499 implementing or overriding that command.
1500
1501 Custom SITE commands have to be written in Perl. However, there is very
1502 little you need to understand in order to write these commands -- you
1503 will only need a basic knowledge of Perl scripting.
1504
1505 As our first example, we will implement a "SITE README" command. This
1506 command just prints out some standard information.
1507
1508 Firstly create a file called "/usr/local/lib/site_readme.pl" (you may
1509 choose a different path if you want). The file should contain:
1510
1511 sub {
1512 my $self = shift;
1513 my $cmd = shift;
1514 my $rest = shift;
1515
1516 $self->reply (200,
1517 "This is the README file for mysite.example.com.",
1518 "Mirrors are contained in /pub/mirrors directory.",
1519 " : : : : :",
1520 "End of the README file.");
1521 }
1522
1523 Edit "/etc/ftpd.conf" and add the following command:
1524
1525 site command: readme /usr/local/lib/site_readme.pl
1526
1527 and restart the FTP server (check your system log [/var/log/messages]
1528 for any syntax errors or other problems). Here is an example of a user
1529 running the SITE README command:
1530
1531 ftp> quote help site
1532 214-The following commands are recognized:
1533 214- ALIAS CHECKMETHOD EXEC README
1534 214- CDPATH CHECKSUM IDLE VERSION
1535 214 You can also use HELP to list general commands.
1536 ftp> site readme
1537 200-This is the README file for mysite.example.com.
1538 200-Mirrors are contained in /pub/mirrors directory.
1539 200- : : : : :
1540 200 End of the README file.
1541
1542 Our second example demonstrates how to use parameters (the $rest
1543 argument). This is the "SITE ECHO" command.
1544
1545 sub {
1546 my $self = shift;
1547 my $cmd = shift;
1548 my $rest = shift;
1549
1550 # Split the parameters up.
1551 my @params = split /\s+/, $rest;
1552
1553 # Quote each parameter.
1554 my $reply = join ", ", map { "'$_'" } @params;
1555
1556 $self->reply (200, "You said: $reply");
1557 }
1558
1559 Here is the "SITE ECHO" command in use:
1560
1561 ftp> quote help site
1562 214-The following commands are recognized:
1563 214- ALIAS CHECKMETHOD ECHO IDLE
1564 214- CDPATH CHECKSUM EXEC VERSION
1565 214 You can also use HELP to list general commands.
1566 ftp> site echo hello how are you?
1567 200 You said: 'hello', 'how', 'are', 'you?'
1568
1569 Our third example is more complex and shows how to interact with the
1570 virtual filesystem (VFS). The "SITE SHOW" command will be used to list
1571 text files directly (the user normally has to download the file and
1572 view it locally). Hence "SITE SHOW readme.txt" should print the
1573 contents of the "readme.txt" file in the local directory (if it
1574 exists).
1575
1576 All file accesses must be done through the VFS, not by directly
1577 accessing the disk. If you follow this convention then your commands
1578 will be secure and will work correctly with different back-end
1579 personalities (in particular when ``files'' are really blobs in a
1580 relational database).
1581
1582 sub {
1583 my $self = shift;
1584 my $cmd = shift;
1585 my $rest = shift;
1586
1587 # Get the file handle.
1588 my ($dirh, $fileh, $filename) = $self->_get ($rest);
1589
1590 # File doesn't exist or not accessible. Return an error.
1591 unless ($fileh)
1592 {
1593 $self->reply (550, "File or directory not found.");
1594 return;
1595 }
1596
1597 # Check it's a simple file.
1598 my ($mode) = $fileh->status;
1599
1600 unless ($mode eq "f")
1601 {
1602 $self->reply (550,
1603 "SITE SHOW command is only supported on plain files.");
1604 return;
1605 }
1606
1607 # Try to open the file.
1608 my $file = $fileh->open ("r");
1609
1610 unless ($file)
1611 {
1612 $self->reply (550, "File or directory not found.");
1613 return;
1614 }
1615
1616 # Copy data into memory.
1617 my @lines = ();
1618
1619 while (defined ($_ = $file->getline))
1620 {
1621 # Remove any native line endings.
1622 s/[\n\r]+$//;
1623
1624 push @lines, $_;
1625 }
1626
1627 # Close the file handle.
1628 unless ($file->close)
1629 {
1630 $self->reply (550, "Close failed: ".$self->system_error_hook());
1631 return;
1632 }
1633
1634 # Send the file back to the user.
1635 $self->reply (200, "File $filename:", @lines, "End of file.");
1636 }
1637
1638 This code is not quite complete. A better implementation would also
1639 check the "retrieve rule" (so that people couldn't use "SITE SHOW" in
1640 order to get around access control limitations which the server
1641 administrator has put in place). It would also check the file more
1642 closely to make sure it was a text file and would refuse to list very
1643 large files.
1644
1645 Here is an example (abbreviated) of a user using the "SITE SHOW"
1646 command:
1647
1648 ftp> site show README
1649 200-File README:
1650 200-README
1651 200-======
1652 200-
1653 200-Biblio@Tech Net::FTPServer - A full-featured, secure, extensible
1654 [...]
1655 200-Copyright (C) 2000-2003 Richard Jones <rich@annexia.org> and other contributors.
1656 200 End of file.
1657
1658 STANDARD PERSONALITIES
1659 Currently "Net::FTPServer" is supplied with three standard
1660 personalities. These are:
1661
1662 Full The complete read/write anonymous/authenticated FTP
1663 server which serves files from a standard Unix filesystem.
1664
1665 RO A small read-only anonymous-only FTP server similar
1666 in functionality to Dan Bernstein's publicfile
1667 program.
1668
1669 DBeg1 An example FTP server which serves files to a PostgreSQL
1670 database. This supports files and hierarchical
1671 directories, multiple users (but not file permissions)
1672 and file upload.
1673
1674 The standard Full personality will not be explained here.
1675
1676 The RO personality is the Full personality with all code related to
1677 writing files, creating directories, deleting, etc. removed. The RO
1678 personality also only permits anonymous logins and does not contain any
1679 code to do ordinary authentication. It is therefore safe to use the RO
1680 personality where you are only interested in serving files to anonymous
1681 users and do not want to worry about crackers discovering a way to
1682 trick the FTP server into writing over a file.
1683
1684 The DBeg1 personality is a complete read/write FTP server which stores
1685 files as BLOBs (Binary Large OBjects) in a PostgreSQL relational
1686 database. The personality supports file download and upload and
1687 contains code to authenticate users against a "users" table in the
1688 database (database ``users'' are thus completely unrelated to real Unix
1689 users). The DBeg1 is intended only as an example. It does not support
1690 advanced features such as file permissions and quotas. As part of the
1691 schoolmaster.net project Bibliotech Ltd. have developed an even more
1692 advanced database personality which supports users, groups, access
1693 control lists, quotas, recursive moves and copies and many other
1694 features. However this database personality is not available as source.
1695
1696 To use the DBeg1 personality you must first run a PostgreSQL server
1697 (version 6.4 or above) and ensure that you have access to it from your
1698 local user account. Use the "initdb", "createdb" and "createuser"
1699 commands to create the appropriate user account and database (please
1700 consult the PostgreSQL administrators manual for further information
1701 about this -- I do not answer questions about basic PostgreSQL
1702 knowledge).
1703
1704 Here is my correctly set up PostgreSQL server, accessed from my local
1705 user account ``rich'':
1706
1707 cruiser:~$ psql
1708 Welcome to the POSTGRESQL interactive sql monitor:
1709 Please read the file COPYRIGHT for copyright terms of POSTGRESQL
1710
1711 type \? for help on slash commands
1712 type \q to quit
1713 type \g or terminate with semicolon to execute query
1714 You are currently connected to the database: rich
1715
1716 rich=> \d
1717 Couldn't find any tables, sequences or indices!
1718
1719 You will also need the following Perl modules installed: DBI, DBD::Pg.
1720
1721 Now you will need to create a database called ``ftp'' and populate it
1722 with data. This is how to do this:
1723
1724 createdb ftp
1725 psql ftp < doc/eg1.sql
1726
1727 Check that no ERRORs are reported by PostgreSQL.
1728
1729 You should now be able to start the FTP server by running the following
1730 command (not as root):
1731
1732 ./dbeg1-ftpd -S -p 2000 -C ftpd.conf
1733
1734 If the FTP server doesn't start correctly, you should check the system
1735 log file [/var/log/messages].
1736
1737 Connect to the FTP server as follows:
1738
1739 ftp localhost 2000
1740
1741 Log in as either rich/123456 or dan/123456 and then try to move around,
1742 upload and download files, create and delete directories, etc.
1743
1744 SUBCLASSING THE Net::FTPServer CLASSES
1745 By subclassing "Net::FTPServer", "Net::FTPServer::DirHandle" and/or
1746 "Net::FTPServer::FileHandle" you can create custom personalities for
1747 the FTP server.
1748
1749 Typically by overriding the hooks in the "Net::FTPServer" class you can
1750 change the basic behaviour of the FTP server - turning it into an
1751 anonymous read-only server, for example.
1752
1753 By overriding the hooks in "Net::FTPServer::DirHandle" and
1754 "Net::FTPServer::FileHandle" you can create virtual filesystems:
1755 serving files into and out of a database, for example.
1756
1757 The current manual page contains information about the hooks in
1758 "Net::FTPServer" which may be overridden.
1759
1760 See Net::FTPServer::DirHandle(3) for information about the methods in
1761 "Net::FTPServer::DirHandle" which may be overridden.
1762
1763 See Net::FTPServer::FileHandle(3) for information about the methods in
1764 "Net::FTPServer::FileHandle" which may be overridden.
1765
1766 The most reasonable way to create your own personality is to extend one
1767 of the existing personalities. Choose the one which most closely
1768 matches the personality that you want to create. For example, suppose
1769 that you want to create another database personality. A good place to
1770 start would be by copying "lib/Net/FTPServer/DBeg1/*.pm" to a new
1771 directory "lib/Net/FTPServer/MyDB/" (for example). Now edit these files
1772 and substitute "MyDB" for "DBeg1". Then examine each subroutine in
1773 these files and modify them, consulting the appropriate manual page if
1774 you need to.
1775
1776 VIRTUAL HOSTS
1777 "Net:FTPServer" is capable of hosting multiple FTP sites on a single
1778 machine. Because of the nature of the FTP protocol, virtual hosting is
1779 almost always done by allocating a single separate IP address per FTP
1780 site. However, "Net::FTPServer" also supports an experimental IP-less
1781 virtual hosting system, although this requires modifications to the
1782 client.
1783
1784 Normal (IP-based) virtual hosting is carried out as follows:
1785
1786 * For each FTP site, allocate a separate IP address.
1787 * Configure IP aliasing on your normal interface so that
1788 the single physical interface responds to multiple
1789 virtual IP addresses.
1790 * Add entries (A records) in DNS mapping each site's
1791 name to a separate IP address.
1792 * Add reverse entries (PTR records) in DNS mapping each
1793 IP address back to the site hostname. It is important
1794 that both forward and reverse DNS is set up correctly,
1795 else virtual hosting may not work.
1796 * In /etc/ftpd.conf you will need to add a virtual host
1797 section for each site like this:
1798
1799 <Host sitename>
1800
1801 ip: 1.2.3.4
1802 ... any specific configuration options for this site ...
1803
1804 </Host>
1805
1806 You don't in fact need the "ip:" part assuming that
1807 your forward and reverse DNS are set up correctly.
1808 * If you want to specify a lot of external sites, or
1809 generate the configuration file automatically from a
1810 database or a script, you may find the <Include filename>
1811 syntax useful.
1812
1813 There are examples in "/etc/ftpd.conf". Here is how IP-based virtual
1814 hosting works:
1815
1816 * The server starts by listening on all interfaces.
1817 * A connection arrives at one of the IP addresses and a
1818 process is forked off.
1819 * The child process finds out which interface the
1820 client connected to and reverses the name.
1821 * If:
1822 the IP address matches one of the "ip:" declarations
1823 in any of the "Host" sections,
1824 or:
1825 there is a reversal for the name, and the name
1826 matches one of the "Host" sections in the configuration
1827 file,
1828 then:
1829 configuration options are read from that
1830 section of the file and override any global configuration
1831 options specified elsewhere in the file.
1832 * Otherwise, the global configuration options only
1833 are used.
1834
1835 IP-less virtual hosting is an experimental feature. It requires the
1836 client to send a "HOST" command very early on in the command stream --
1837 before "USER" and "PASS". The "HOST" command explicitly gives the
1838 hostname that the FTP client is attempting to connect to, and so allows
1839 many FTP sites to be multiplexed onto a single IP address. At the
1840 present time, I am not aware of any FTP clients which implement the
1841 "HOST" command, although they will undoubtedly become more common in
1842 future.
1843
1844 This is how to set up IP-less virtual hosting:
1845
1846 * Add entries (A or CNAME records) in DNS mapping the
1847 name of each site to a single IP address.
1848 * In /etc/ftpd.conf you will need to list the same single
1849 IP address to which all your sites map:
1850
1851 virtual host multiplex: 1.2.3.4
1852
1853 * In /etc/ftpd.conf you will need to add a virtual host
1854 section for each site like this:
1855
1856 <Host sitename>
1857
1858 ... any specific configuration options for this site ...
1859
1860 </Host>
1861
1862 Here is how IP-less virtual hosting works:
1863
1864 * The server starts by listening on one interface.
1865 * A connection arrives at the IP address and a
1866 process is forked off.
1867 * The IP address matches "virtual host multiplex"
1868 and so no IP-based virtual host processing is done.
1869 * One of the first commands that the client sends is
1870 "HOST" followed by the hostname of the site.
1871 * If there is a matching "Host" section in the
1872 configuration file, then configuration options are
1873 read from that section of the file and override any
1874 global configuration options specified elsewhere in
1875 the file.
1876 * If there is no matching "Host" section then the
1877 global configuration options alone are used.
1878
1879 The client is not permitted to issue the "HOST" command more than once,
1880 and is not permitted to issue it after login.
1881
1882 VIRTUAL HOSTING AND SECURITY
1883 Only certain configuration options are available inside the <Host>
1884 sections of the configuration file. Generally speaking, the only
1885 configuration options you can put here are ones which take effect after
1886 the site name has been determined -- hence "allow anonymous" is OK
1887 (since it's an option which is parsed after determining the site name
1888 and during log in), but "port" is not (since it is parsed long before
1889 any clients ever connect).
1890
1891 Make sure your default global configuration is secure. If you are using
1892 IP-less virtual hosting, this is particularly important, since if the
1893 client never sends a "HOST" command, the client gets the global
1894 configuration. Even with IP-based virtual hosting it may be possible
1895 for clients to sometimes get the global configuration, for example if
1896 your local name server fails.
1897
1898 IP-based virtual hosting always takes precedence above IP-less virtual
1899 hosting.
1900
1901 With IP-less virtual hosting, access control cannot be performed on a
1902 per-site basis. This is because the client has to issue commands (ie.
1903 the "HOST" command at least) before the site name is known to the
1904 server. However you may still have a global "access control rule".
1905
1906 ARCHIVE MODE
1907 Beginning with version 1.100, "Net::FTPServer" is able to generate
1908 certain types of compressed and archived files on the fly. In practice
1909 what this means is that if a user requests, say, "file.gz" and this
1910 file does not actually exist (but "file" does exist), then the server
1911 will dynamically generate a gzip-compressed version of "file" for the
1912 user. This also works on directories, so that a user might request
1913 "dir.tar.gz" which does not exist (but directory "dir" does exist), and
1914 the server tars up and compresses the entire contents of "dir" and
1915 presents that back to the user.
1916
1917 Archive mode is enabled by default. However, it will not work unless
1918 you substantially increase the per-process memory, processes and files
1919 limits. The reason for this is that archive mode works by forking
1920 external programs such as "gzip" to perform the compression. For the
1921 same reason you may also need to ensure that at least "gzip",
1922 "compress", "bzip2" and "uuencode" programs are available on the
1923 current $PATH, particularly if you are using a chrooted environment.
1924
1925 To disable archive mode put "enable archive mode: 0" into the
1926 configuration file.
1927
1928 The following file extensions are supported:
1929
1930 .gz GZip compressed. Requires gzip program on PATH.
1931 .Z Unix compressed. Requires compress program on PATH.
1932 .bz2 BZip2 compressed. Requires bzip2 program on PATH.
1933 .uue UU-encoded. Requires uuencode program on PATH.
1934 .tar Tar archive. Requires Perl Archive::Tar module.
1935 .zip DOS ZIP archive. Requires Perl Archive::Zip module.
1936 .list Return a list of all the files in this directory.
1937
1938 File extensions may be combined. Hence ".tar.gz", ".tar.bz2" and even
1939 ".tar.gz.uue" will all work as you expect.
1940
1941 Archive mode is, of course, extensible. It is particularly simple to
1942 add another compression / filter format. In your personality (or in a
1943 <Perl> section in the configuration file) you need to add another key
1944 to the "archive_filters" hash.
1945
1946 $ftps->{archive_filters}{".foo"} = &_foo_filter;
1947
1948 The value of this key should be a function as defined below:
1949
1950 \%filter = _foo_filter ($ftps, $sock);
1951
1952 The filter should return a hash reference (undef if it fails). The
1953 hash should contain the following keys:
1954
1955 sock Newly opened socket.
1956 pid PID of filter program.
1957
1958 The "_foo_filter" function takes the existing socket and filters it,
1959 providing a new socket which the FTP server will write to (for the data
1960 connection back to the client). If your filter is a Unix program, then
1961 the simplest thing is just to define "_foo_filter" as:
1962
1963 sub _foo_filter
1964 {
1965 return $_[0]->archive_filter_external ($_[1], "foo" [, args ...]);
1966 }
1967
1968 The "archive_filter_external" function takes care of the tricky bits
1969 for you.
1970
1971 Adding new generators (akin to the existing tar and ZIP) is more
1972 tricky. I suggest you look closely at the code and consult the author
1973 for more information.
1974
1976 Net::FTPServer->run ([\@ARGV]);
1977 This is the main entry point into the FTP server. It starts the FTP
1978 server running. This function never normally returns.
1979
1980 If no arguments are given, then command line arguments are taken
1981 from the global @ARGV array.
1982
1983 $regex = $ftps->wildcard_to_regex ($wildcard)
1984 This is a general library function shared between many of the back-
1985 end database personalities. It converts a general wildcard (eg.
1986 *.c) into a regular expression (eg. ^.*\.c$ ).
1987
1988 Thanks to: Terrence Monroe Brannon <terrence.brannon@oracle.com>.
1989
1990 $regex = $ftps->wildcard_to_sql_like ($wildcard)
1991 This is a general library function shared between many of the back-
1992 end database personalities. It converts a general wildcard (eg.
1993 *.c) into the strange wildcardish format used by SQL LIKE operator
1994 (eg. %.c).
1995
1996 $ftps->reply ($code, $line, [$line, ...])
1997 This function sends a standard single line or multi-line FTP server
1998 reply to the client. The $code should be one of the standard reply
1999 codes listed in RFC 959. The one or more $line arguments are the
2000 (free text) of the reply. Do not include carriage returns at the
2001 end of each $line. This function adds the correct line ending
2002 format as specified in the RFC.
2003
2004 $ftps->log ($level, $message, ...);
2005 This function is identical to the normal "syslog" function to be
2006 found in "Sys::Syslog". However, it only uses syslog if the "enable
2007 syslog" configuration option is set to true.
2008
2009 Use this function instead of calling "syslog" directly.
2010
2011 $ftps->config ($name);
2012 Read configuration option $name from the configuration file.
2013
2014 $ftps->ip_host_config ($ip_addr);
2015 Look for a <Host> section which contains "ip: $ip_addr". If one is
2016 found, return the site name of the Host section. Otherwise return
2017 undef.
2018
2019 $filter = $ftps->archive_filter_external ($sock, $cmd [, $args]);
2020 Apply $cmd as a filter to socket $sock. Returns a hash reference
2021 which contains the following keys:
2022
2023 sock Newly opened socket.
2024 pid PID of filter program.
2025
2026 If it fails, returns "undef".
2027
2028 See section ARCHIVE MODE elsewhere in this manual for more
2029 information.
2030
2031 $ftps->visit ($dirh, \%functions);
2032 The "visit" function recursively "visits" every file and directory
2033 contained in $dirh (which must be a directory handle).
2034
2035 "\%functions" is a reference to a hash of file types to functions.
2036 For example:
2037
2038 'f' => \&visit_file,
2039 'd' => \&visit_directory,
2040 'l' => \&visit_symlink,
2041 &c.
2042
2043 When a file of the known type is encountered, the appropriate
2044 function is called with $_ set to the file handle. (All functions
2045 are optional: if "visit" encounters a file with a type not listed
2046 in the %functions hash, then that file is just ignored).
2047
2048 The return value from functions is ignored, except for the return
2049 value from the directory ('d') function. The directory function
2050 should return 1 to indicate that "visit" should recurse into that
2051 directory. If the directory function returns 0, then "visit" will
2052 skip that directory.
2053
2054 "visit" will call the directory function once for $dirh.
2055
2056 $sock = $self->open_data_connection;
2057 Open a data connection. Returns the socket (an instance of
2058 "IO::Socket") or undef if it fails for some reason.
2059
2060 $self->pre_configuration_hook ();
2061 Hook: Called before command line arguments and configuration file
2062 are read.
2063
2064 Status: optional.
2065
2066 Notes: You may append your own information to
2067 "$self->{version_string}" from this hook.
2068
2069 $self->options_hook (\@args);
2070 Hook: Called before command line arguments are parsed.
2071
2072 Status: optional.
2073
2074 Notes: You can use this hook to supply your own command line
2075 arguments. If you parse any arguments, you should remove them from
2076 the @args array.
2077
2078 $self->post_configuration_hook ();
2079 Hook: Called after all command line arguments and configuration
2080 file have been read and parsed.
2081
2082 Status: optional.
2083
2084 $self->post_bind_hook ();
2085 Hook: Called only in daemon mode after the control port is bound
2086 but before starting the accept infinite loop block.
2087
2088 Status: optional.
2089
2090 $self->pre_accept_hook ();
2091 Hook: Called in daemon mode only just before accept(2) is called in
2092 the parent FTP server process.
2093
2094 Status: optional.
2095
2096 $self->post_accept_hook ();
2097 Hook: Called both in daemon mode and in inetd mode just after the
2098 connection has been accepted. This is called in the child process.
2099
2100 Status: optional.
2101
2102 $rv = $self->access_control_hook;
2103 Hook: Called after accept(2)-ing the connection to perform access
2104 control. Detailed request information is contained in the $self
2105 object. If the function returns -1 then the socket is immediately
2106 closed and no FTP processing happens on it. If the function returns
2107 0, then normal access control is performed on the socket before FTP
2108 processing starts. If the function returns 1, then normal access
2109 control is not performed on the socket and FTP processing begins
2110 immediately.
2111
2112 Status: optional.
2113
2114 $rv = $self->process_limits_hook;
2115 Hook: Called after accept(2)-ing the connection to perform per-
2116 process limits (eg. by using the setrlimit(2) system call). Access
2117 control has already been performed and detailed request information
2118 is contained in the $self object.
2119
2120 If the function returns -1 then the socket is immediately closed
2121 and no FTP processing happens on it. If the function returns 0,
2122 then normal per-process limits are applied before any FTP
2123 processing starts. If the function returns 1, then normal per-
2124 process limits are not performed and FTP processing begins
2125 immediately.
2126
2127 Status: optional.
2128
2129 $rv = $self->authentication_hook ($user, $pass, $user_is_anon)
2130 Hook: Called to perform authentication. If the authentication
2131 succeeds, this should return 0 (or any positive integer >= 0). If
2132 the authentication fails, this should return -1.
2133
2134 Status: required.
2135
2136 $self->user_login_hook ($user, $user_is_anon)
2137 Hook: Called just after user $user has successfully logged in. A
2138 good place to change uid and chroot if necessary.
2139
2140 Status: optional.
2141
2142 $dirh = $self->root_directory_hook;
2143 Hook: Return an instance of a subclass of Net::FTPServer::DirHandle
2144 corresponding to the root directory.
2145
2146 Status: required.
2147
2148 $self->pre_command_hook;
2149 Hook: This hook is called just before the server begins to wait for
2150 the client to issue the next command over the control connection.
2151
2152 Status: optional.
2153
2154 $rv = $self->command_filter_hook ($cmdline);
2155 Hook: This hook is called immediately after the client issues
2156 command $cmdline, but before any checking or processing is
2157 performed on the command. If this function returns -1, then the
2158 server immediately goes back to waiting for the next command. If
2159 this function returns 0, then normal command filtering is carried
2160 out and the command is processed. If this function returns 1 then
2161 normal command filtering is not performed and the command
2162 processing begins immediately.
2163
2164 Important Note: This hook must be careful not to overwrite the
2165 global $_ variable.
2166
2167 Do not use this function to add your own commands. Instead use the
2168 "$self->{command_table}" and "$self->{site_command_table}" hashes.
2169
2170 Status: optional.
2171
2172 $error = $self->transfer_hook ($mode, $file, $sock, \$buffer);
2173 $mode - Open mode on the File object (Either reading or writing)
2174 $file - File object as returned from DirHandle::open
2175 $sock - Data IO::Socket object used for transfering
2176 \$buffer - Reference to current buffer about to be written
2177
2178 The \$buffer is passed by reference to minimize the stack overhead
2179 for efficiency purposes only. It is not meant to be modified by
2180 the transfer_hook subroutine. (It can cause corruption if the
2181 length of $buffer is modified.)
2182
2183 Hook: This hook is called after reading $buffer and before writing
2184 $buffer to its destination. If arg1 is "r", $buffer was read from
2185 the File object and written to the Data socket. If arg1 is "w",
2186 $buffer will be written to the File object because it was read from
2187 the Data Socket. The return value is the error for not being able
2188 to perform the write. Return undef to avoid aborting the transfer
2189 process.
2190
2191 Status: optional.
2192
2193 $self->post_command_hook ($cmd, $rest)
2194 Hook: This hook is called after all command processing has been
2195 carried out on this command. $cmd is the command, and $rest is the
2196 remainder of the command line.
2197
2198 Status: optional.
2199
2200 $self->system_error_hook
2201 Hook: This hook is used instead of $! when what looks like a system
2202 error occurs during a virtual filesystem handle method. It can be
2203 used by the virtual filesystem to provide explanatory text for a
2204 virtual filesystem failure which did not actually set the real $!.
2205
2206 Status: optional.
2207
2208 $self->quit_hook
2209 Hook: This hook is called after the user has "QUIT" or if the FTP
2210 client cleanly drops the connection. Please note, however, that
2211 this hook is not called whenever the FTP server exits, particularly
2212 in cases such as:
2213
2214 * The FTP server, the Perl interpreter or the personality
2215 crashes unexpectedly.
2216 * The user fails to log in.
2217 * The FTP server detects a fatal error, sends a "421" error code,
2218 and abruptly exits.
2219 * Idle timeouts.
2220 * Access control violations.
2221 * Manual server shutdowns.
2222
2223 Unfortunately it is not in general easily possible to catch these
2224 cases and cleanly call a hook. If your personality needs to do
2225 cleanup in all cases, then it is probably better to use an "END"
2226 block inside your Server object (see perlmod(3)). Even using an
2227 "END" block cannot catch cases where the Perl interpreter crashes.
2228
2229 Status: optional.
2230
2232 The SIZE, REST and RETR commands probably do not work correctly in
2233 ASCII mode.
2234
2235 REST does not work before STOR/STOU/APPE (is it supposed to?)
2236
2237 User upload/download limits.
2238
2239 Limit number of clients by host or IP address.
2240
2241 The following commands are recognized by "wu-ftpd", but are not yet
2242 implemented by "Net::FTPServer":
2243
2244 SITE CHMOD There is a problem supporting this with our VFS.
2245 SITE GPASS Group functions are not really relevant for us.
2246 SITE GROUP -"- ditto -"-
2247 SITE GROUPS -"- ditto -"-
2248 SITE INDEX This is a synonym for SITE EXEC.
2249 SITE MINFO This command is no longer supported by wu-ftpd.
2250 SITE NEWER This command is no longer supported by wu-ftpd.
2251 SITE UMASK This command is difficult to support with VFS.
2252
2253 Symbolic links are not handled elegantly (or indeed at all) yet.
2254
2255 Equivalent of ProFTPD's ``DisplayReadme'' function.
2256
2257 The ability to hide dot files (probably best to build this into the VFS
2258 layer). This should apply across all commands. See ProFTPD's
2259 ``IgnoreHidden'' function.
2260
2261 Access to LDAP authentication database (can currently be done using a
2262 PAM module). In general, we should support pluggable authentication.
2263
2264 Log formatting similar to ProFTPD command LogFormat.
2265
2266 More timeouts to avoid various denial of service attacks. For example,
2267 the server should always timeout when waiting too long for an active
2268 data connection.
2269
2270 Support for IPv6 (see RFC 2428), EPRT, EPSV commands.
2271
2272 See also "XXX" comments in the code for other problems, missing
2273 features and bugs.
2274
2276 IO::Dir, IO::stringy
2277
2279 Richard Jones (rich@annexia.org), Rob Brown (bbb@cpan.org), Keith
2280 Turner (keitht at silvaco.com), Azazel (azazel at azazel.net), and many
2281 others.
2282
2284 Ryo Okamoto "<ryo at aquahill dot net>"
2285
2287 https://github.com/ryochin/p5-net-ftpserver
2288
2290 Copyright (C) 2000 Biblio@Tech Ltd., Unit 2-3, 50 Carnwath Road,
2291 London, SW6 3EG, UK.
2292
2293 Copyright (C) 2000-2003 Richard Jones (rich@annexia.org) and other
2294 contributors.
2295
2296 This program is free software; you can redistribute it and/or modify it
2297 under the terms of the GNU General Public License as published by the
2298 Free Software Foundation; either version 2 of the License, or (at your
2299 option) any later version.
2300
2301 This program is distributed in the hope that it will be useful, but
2302 WITHOUT ANY WARRANTY; without even the implied warranty of
2303 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
2304 General Public License for more details.
2305
2306 You should have received a copy of the GNU General Public License along
2307 with this program; if not, write to the Free Software Foundation, Inc.,
2308 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
2309
2311 Net::FTPServer::Handle(3), Net::FTPServer::FileHandle(3),
2312 Net::FTPServer::DirHandle(3), Net::FTP(3), perl(1), RFC 765, RFC 959,
2313 RFC 1579, RFC 2389, RFC 2428, RFC 2577, RFC 2640, Extensions to FTP
2314 Internet Draft draft-ietf-ftpext-mlst-NN.txt. Net::FTPServer::XferLog
2315 Test::FTP::Server
2316
2317
2318
2319perl v5.32.1 2021-01-27 Net::FTPServer(3)