1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937
|
/* Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: J.Wielemaker@vu.nl
WWW: http://www.swi-prolog.org
Copyright (c) 2013-2022, University of Amsterdam
VU University Amsterdam
CWI, Amsterdam
SWI-Prolog Solutions b.v.
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
*/
:- module(http_unix_daemon,
[ http_daemon/0,
http_daemon/1 % +Options
]).
:- use_module(library(error)).
:- use_module(library(apply)).
:- use_module(library(lists)).
:- use_module(library(debug)).
:- use_module(library(broadcast)).
:- use_module(library(socket)).
:- use_module(library(option)).
:- use_module(library(uid)).
:- use_module(library(unix)).
:- use_module(library(syslog)).
:- use_module(library(http/thread_httpd)).
:- use_module(library(http/http_dispatch)).
:- use_module(library(http/http_host)).
:- use_module(library(main)).
:- use_module(library(readutil)).
:- if(( exists_source(library(http/http_ssl_plugin)),
\+ current_prolog_flag(pldoc_to_tex,true))).
:- use_module(library(ssl)).
:- use_module(library(http/http_ssl_plugin)).
:- endif.
:- multifile
http_server_hook/1, % +Options
http_certificate_hook/3, % +CertFile, +KeyFile, -Password
http:sni_options/2. % +HostName, +SSLOptions
:- initialization(http_daemon, main).
/** <module> Run SWI-Prolog HTTP server as a Unix system daemon
This module provides the logic that is needed to integrate a process
into the Unix service (daemon) architecture. It deals with the following
aspects, all of which may be used/ignored and configured using
commandline options:
- Select the port(s) to be used by the server
- Run the startup of the process as root to perform privileged
tasks and the server itself as unpriviledged user, for example
to open ports below 1000.
- Fork and detach from the controlling terminal
- Handle console and debug output using a file and/or the syslog
daemon.
- Manage a _|pid file|_
The typical use scenario is to write a file that loads the following
components:
1. The application code, including http handlers (see http_handler/3).
2. This library
In the code below, =|?- [load].|= loads the remainder of the webserver
code. This is often a sequence of use_module/1 directives.
==
:- use_module(library(http/http_unix_daemon)).
:- [load].
==
The program entry point is http_daemon/0, declared using
initialization/2. This may be overruled using a new declaration after
loading this library. The new entry point will typically call
http_daemon/1 to start the server in a preconfigured way.
==
:- use_module(library(http/http_unix_daemon)).
:- initialization(run, main).
run :-
...
http_daemon(Options).
==
Now, the server may be started using the command below. See
http_daemon/0 for supported options.
==
% [sudo] swipl mainfile.pl [option ...]
==
Below are some examples. Our first example is completely silent, running
on port 80 as user =www=.
==
% swipl mainfile.pl --user=www --pidfile=/var/run/http.pid
==
Our second example logs HTTP interaction with the syslog daemon for
debugging purposes. Note that the argument to =|--debug|== is a Prolog
term and must often be escaped to avoid misinterpretation by the Unix
shell. The debug option can be repeated to log multiple debug topics.
==
% swipl mainfile.pl --user=www --pidfile=/var/run/http.pid \
--debug='http(request)' --syslog=http
==
*Broadcasting* The library uses broadcast/1 to allow hooking certain
events:
- http(pre_server_start)
Run _after_ _fork_, just before starting the HTTP server. Can be used
to load additional files or perform additional initialisation, such as
starting additional threads. Recall that it is not possible to start
threads _before_ forking.
- http(post_server_start)
Run _after_ starting the HTTP server.
@tbd Cleanup issues wrt. loading and initialization of xpce.
@see The file <swi-home>/doc/packages/examples/http/linux-init-script
provides a /etc/init.d script for controlling a server as a normal
Unix service.
*/
:- debug(daemon).
% Do not run xpce in a thread. This disables forking. The problem here
% is that loading library(pce) starts the event dispatching thread. This
% should be handled lazily.
:- set_prolog_flag(xpce_threaded, false).
:- set_prolog_flag(message_ide, false). % cause xpce to trap messages
:- set_prolog_flag(message_context, [thread,time('%F %T.%3f')]).
:- dynamic interactive/0.
%! http_daemon
%
% Start the HTTP server as a daemon process. This predicate
% processes the commandline arguments below. Commandline arguments
% that specify servers are processed in the order they appear
% using the following schema:
%
% 1. Arguments that act as default for all servers.
% 2. =|--http=Spec|= or =|--https=Spec|= is followed by
% arguments for that server until the next =|--http=Spec|=
% or =|--https=Spec|= or the end of the options.
% 3. If no =|--http=Spec|= or =|--https=Spec|= appears, one
% HTTP server is created from the specified parameters.
%
% Examples:
%
% ==
% --workers=10 --http --https
% --http=8080 --https=8443
% --http=localhost:8080 --workers=1 --https=8443 --workers=25
% ==
%
% $ --port=Port :
% Start HTTP server at Port. It requires root permission and the
% option =|--user=User|= to open ports below 1000. The default
% port is 80. If =|--https|= is used, the default port is 443.
%
% $ --ip=IP :
% Only listen to the given IP address. Typically used as
% =|--ip=localhost|= to restrict access to connections from
% _localhost_ if the server itself is behind an (Apache)
% proxy server running on the same host.
%
% $ --debug=Topic :
% Enable debugging Topic. See debug/3.
%
% $ --syslog=Ident :
% Write debug messages to the syslog daemon using Ident
%
% $ --user=User :
% When started as root to open a port below 1000, this option
% must be provided to switch to the target user for operating
% the server. The following actions are performed as root, i.e.,
% _before_ switching to User:
%
% - open the socket(s)
% - write the pidfile
% - setup syslog interaction
% - Read the certificate, key and password file (=|--pwfile=File|=)
%
% $ --group=Group :
% May be used in addition to =|--user|=. If omitted, the login
% group of the target user is used.
%
% $ --pidfile=File :
% Write the PID of the daemon process to File.
%
% $ --output=File :
% Send output of the process to File. By default, all
% Prolog console output is discarded.
%
% $ --fork[=Bool] :
% If given as =|--no-fork|= or =|--fork=false|=, the process
% runs in the foreground.
%
% $ --http[=(Bool|Port|BindTo:Port)] :
% Create a plain HTTP server. If the argument is missing or
% =true=, create at the specified or default address. Else
% use the given port and interface. Thus, =|--http|= creates
% a server at port 80, =|--http=8080|= creates one at port
% 8080 and =|--http=localhost:8080|= creates one at port
% 8080 that is only accessible from `localhost`.
%
% $ --https[=(Bool|Port|BindTo:Port)] :
% As =|--http|=, but creates an HTTPS server.
% Use =|--certfile|=, =|--keyfile|=, =|-pwfile|=,
% =|--password|= and =|--cipherlist|= to configure SSL for
% this server.
%
% $ --certfile=File :
% The server certificate for HTTPS.
%
% $ --keyfile=File :
% The server private key for HTTPS.
%
% $ --pwfile=File :
% File holding the password for accessing the private key. This
% is preferred over using =|--password=PW|= as it allows using
% file protection to avoid leaking the password. The file is
% read _before_ the server drops privileges when started with
% the =|--user|= option.
%
% $ --password=PW :
% The password for accessing the private key. See also `--pwfile`.
%
% $ --cipherlist=Ciphers :
% One or more cipher strings separated by colons. See the OpenSSL
% documentation for more information. Starting with SWI-Prolog
% 7.5.11, the default value is always a set of ciphers that was
% considered secure enough to prevent all critical attacks at the
% time of the SWI-Prolog release.
%
% $ --interactive[=Bool] :
% If =true= (default =false=) implies =|--no-fork|= and presents
% the Prolog toplevel after starting the server.
%
% $ --gtrace=[Bool] :
% Use the debugger to trace http_daemon/1.
%
% $ --sighup=Action :
% Action to perform on =|kill -HUP <pid>|=. Default is `reload`
% (running make/0). Alternative is `quit`, stopping the server.
%
% Other options are converted by argv_options/3 and passed to
% http_server/1. For example, this allows for:
%
% $ --workers=Count :
% Set the number of workers for the multi-threaded server.
%
% http_daemon/0 is defined as below. The start code for a specific
% server can use this as a starting point, for example for specifying
% defaults.
%
% ```
% http_daemon :-
% current_prolog_flag(argv, Argv),
% argv_options(Argv, _RestArgv, Options),
% http_daemon(Options).
% ```
%
% @see http_daemon/1
http_daemon :-
current_prolog_flag(argv, Argv),
argv_options(Argv, _RestArgv, Options),
http_daemon(Options).
%! http_daemon(+Options)
%
% Start the HTTP server as a daemon process. This predicate processes
% a Prolog option list. It is normally called from http_daemon/0,
% which derives the option list from the command line arguments.
%
% Error handling depends on whether or not interactive(true) is in
% effect. If so, the error is printed before entering the toplevel. In
% non-interactive mode this predicate calls halt(1).
http_daemon(Options) :-
catch(http_daemon_guarded(Options), Error, start_failed(Error)).
start_failed(Error) :-
interactive,
!,
print_message(warning, Error).
start_failed(Error) :-
print_message(error, Error),
halt(1).
%! http_daemon_guarded(+Options)
%
% Helper that is started from http_daemon/1. See http_daemon/1 for
% options that are processed.
http_daemon_guarded(Options) :-
option(help(true), Options),
!,
print_message(information, http_daemon(help)),
halt.
http_daemon_guarded(Options) :-
setup_debug(Options),
kill_x11(Options),
option_servers(Options, Servers0),
maplist(make_socket, Servers0, Servers),
( option(fork(true), Options, true),
option(interactive(false), Options, false),
can_switch_user(Options)
-> fork(Who),
( Who \== child
-> halt
; disable_development_system,
setup_syslog(Options),
write_pid(Options),
setup_output(Options),
switch_user(Options),
setup_signals(Options),
start_servers(Servers),
wait(Options)
)
; write_pid(Options),
switch_user(Options),
setup_signals(Options),
start_servers(Servers),
wait(Options)
).
%! option_servers(+Options, -Sockets:list)
%
% Find all sockets that must be created according to Options. Each
% socket is a term server(Scheme, Address, Opts), where Address is
% either a plain port (integer) or Host:Port. The latter binds the
% port to the interface belonging to Host. For example:
% socket(http, localhost:8080, Opts) creates an HTTP socket that
% binds to the localhost interface on port 80. Opts are the
% options specific for the given server.
option_servers(Options, Sockets) :-
opt_sockets(Options, [], [], Sockets).
opt_sockets([], Options, [], [Socket]) :-
!,
make_server(http(true), Options, Socket).
opt_sockets([], _, Sockets, Sockets).
opt_sockets([H|T], OptsH, Sockets0, Sockets) :-
server_option(H),
!,
append(OptsH, [H], OptsH1),
opt_sockets(T, OptsH1, Sockets0, Sockets).
opt_sockets([H|T0], Opts, Sockets0, Sockets) :-
server_start_option(H),
!,
server_options(T0, T, Opts, SOpts),
make_server(H, SOpts, Socket),
append(Sockets0, [Socket], Sockets1),
opt_sockets(T, Opts, Sockets1, Sockets).
opt_sockets([_|T], Opts, Sockets0, Sockets) :-
opt_sockets(T, Opts, Sockets0, Sockets).
server_options([], [], Options, Options).
server_options([H|T], Rest, Options0, Options) :-
server_option(H),
!,
generalise_option(H, G),
delete(Options0, G, Options1),
append(Options1, [H], Options2),
server_options(T, Rest, Options2, Options).
server_options([H|T], [H|T], Options, Options) :-
server_start_option(H),
!.
server_options([_|T0], Rest, Options0, Options) :-
server_options(T0, Rest, Options0, Options).
generalise_option(H, G) :-
H =.. [Name,_],
G =.. [Name,_].
server_start_option(http(_)).
server_start_option(https(_)).
server_option(port(_)).
server_option(ip(_)).
server_option(certfile(_)).
server_option(keyfile(_)).
server_option(pwfile(_)).
server_option(password(_)).
server_option(cipherlist(_)).
server_option(workers(_)).
server_option(redirect(_)).
server_option(timeout(_)).
server_option(keep_alive_timeout(_)).
make_server(http(Address0), Options0, server(http, Address, Options)) :-
make_address(Address0, 80, Address, Options0, Options).
make_server(https(Address0), Options0, server(https, Address, SSLOptions)) :-
make_address(Address0, 443, Address, Options0, Options),
merge_https_options(Options, SSLOptions).
make_address(true, DefPort, Address, Options0, Options) :-
!,
option(port(Port), Options0, DefPort),
( option(ip(Bind), Options0)
-> Address = (Bind:Port)
; Address = Port
),
merge_options([port(Port)], Options0, Options).
make_address(Bind:Port, _, Bind:Port, Options0, Options) :-
!,
must_be(atom, Bind),
must_be(integer, Port),
merge_options([port(Port), ip(Bind)], Options0, Options).
make_address(Port, _, Address, Options0, Options) :-
integer(Port),
!,
( option(ip(Bind), Options0)
-> Address = (Bind:Port)
; Address = Port,
merge_options([port(Port)], Options0, Options)
).
make_address(Spec, _, Address, Options0, Options) :-
atomic(Spec),
split_string(Spec, ":", "", [BindString, PortString]),
number_string(Port, PortString),
!,
atom_string(Bind, BindString),
Address = (Bind:Port),
merge_options([port(Port), ip(Bind)], Options0, Options).
make_address(Spec, _, _, _, _) :-
domain_error(address, Spec).
:- dynamic sni/3.
merge_https_options(Options, [SSL|Options]) :-
( option(certfile(CertFile), Options),
option(keyfile(KeyFile), Options)
-> prepare_https_certificate(CertFile, KeyFile, Passwd0),
read_file_to_string(CertFile, Certificate, []),
read_file_to_string(KeyFile, Key, []),
Pairs = [Certificate-Key]
; Pairs = []
),
ssl_secure_ciphers(SecureCiphers),
option(cipherlist(CipherList), Options, SecureCiphers),
( string(Passwd0)
-> Passwd = Passwd0
; options_password(Options, Passwd)
),
findall(HostName-HostOptions, http:sni_options(HostName, HostOptions), SNIs),
maplist(sni_contexts, SNIs),
SSL = ssl([ certificate_key_pairs(Pairs),
cipher_list(CipherList),
password(Passwd),
sni_hook(http_unix_daemon:sni)
]).
sni_contexts(Host-Options) :-
ssl_context(server, SSL, Options),
assertz(sni(_, Host, SSL)).
%! http_certificate_hook(+CertFile, +KeyFile, -Password) is semidet.
%
% Hook called before starting the server if the --https option is
% used. This hook may be used to create or refresh the
% certificate. If the hook binds Password to a string, this string
% will be used to decrypt the server private key as if the
% --password=Password option was given.
prepare_https_certificate(CertFile, KeyFile, Password) :-
http_certificate_hook(CertFile, KeyFile, Password),
!.
prepare_https_certificate(_, _, _).
options_password(Options, Passwd) :-
option(password(Passwd), Options),
!.
options_password(Options, Passwd) :-
option(pwfile(File), Options),
!,
read_file_to_string(File, String, []),
split_string(String, "", "\r\n\t ", [Passwd]).
options_password(_, '').
%! start_servers(+Servers) is det.
%
% Start the HTTP server. It performs the following steps:
%
% 1. Call broadcast(http(pre_server_start))
% 2. Foreach server
% a. Call broadcast(http(pre_server_start(Port)))
% b. Call http_server(http_dispatch, Options)
% c. Call broadcast(http(post_server_start(Port)))
% 3. Call broadcast(http(post_server_start))
%
% This predicate can be hooked using http_server_hook/1. This
% predicate is executed after
%
% - Forking
% - Setting I/O (e.g., to talk to the syslog daemon)
% - Dropping root privileges (--user)
% - Setting up signal handling
start_servers(Servers) :-
broadcast(http(pre_server_start)),
maplist(start_server, Servers),
broadcast(http(post_server_start)).
start_server(server(_Scheme, Socket, Options)) :-
option(redirect(To), Options),
!,
http_server(server_redirect(To), [tcp_socket(Socket)|Options]).
start_server(server(_Scheme, Socket, Options)) :-
http_server_hook([tcp_socket(Socket)|Options]),
!.
start_server(server(_Scheme, Socket, Options)) :-
option(port(Port), Options),
broadcast(http(pre_server_start(Port))),
http_server(http_dispatch, [tcp_socket(Socket)|Options]),
broadcast(http(post_server_start(Port))).
make_socket(server(Scheme, Address, Options),
server(Scheme, Socket, Options)) :-
tcp_socket(Socket),
catch(bind_socket(Socket, Address), Error,
make_socket_error(Error, Address)),
debug(daemon(socket),
'Created socket ~p, listening on ~p', [Socket, Address]).
bind_socket(Socket, Address) :-
tcp_setopt(Socket, reuseaddr),
tcp_bind(Socket, Address),
tcp_listen(Socket, 5).
make_socket_error(error(socket_error(_,_), _), Address) :-
address_port(Address, Port),
integer(Port),
Port =< 1000,
!,
verify_root(open_port(Port)).
make_socket_error(Error, _) :-
throw(Error).
address_port(_:Port, Port) :- !.
address_port(Port, Port).
%! disable_development_system
%
% Disable some development stuff.
disable_development_system :-
set_prolog_flag(editor, '/bin/false').
%! enable_development_system
%
% Re-enable the development environment. Currently re-enables xpce if
% this was loaded, but not initialised and causes the interactive
% toplevel to be re-enabled.
enable_development_system :-
assertz(interactive),
set_prolog_flag(xpce_threaded, true),
set_prolog_flag(message_ide, true),
( current_prolog_flag(xpce_version, _)
-> call(pce_dispatch([]))
; true
),
set_prolog_flag(toplevel_goal, prolog).
%! setup_syslog(+Options) is det.
%
% Setup syslog interaction.
setup_syslog(Options) :-
option(syslog(Ident), Options),
!,
openlog(Ident, [pid], user).
setup_syslog(_).
%! setup_output(+Options) is det.
%
% Setup output from the daemon process. The default is to send all
% output to a null-stream (see open_null_stream/1). With the
% option output(File), all output is written to File.
setup_output(Options) :-
option(output(File), Options),
!,
open(File, write, Out, [encoding(utf8)]),
set_stream(Out, buffer(line)),
detach_IO(Out).
setup_output(_) :-
open_null_stream(Out),
detach_IO(Out).
%! write_pid(+Options) is det.
%
% If the option pidfile(File) is present, write the PID of the
% daemon to this file.
write_pid(Options) :-
option(pidfile(File), Options),
current_prolog_flag(pid, PID),
!,
setup_call_cleanup(
open(File, write, Out),
format(Out, '~d~n', [PID]),
close(Out)),
at_halt(catch(delete_file(File), _, true)).
write_pid(_).
%! switch_user(+Options) is det.
%
% Switch to the target user and group. If the server is started as
% root, this option *must* be present.
switch_user(Options) :-
option(user(User), Options),
!,
verify_root(switch_user(User)),
( option(group(Group), Options)
-> set_user_and_group(User, Group)
; set_user_and_group(User)
),
prctl(set_dumpable(true)). % re-enable core dumps on Linux
switch_user(_Options) :-
verify_no_root.
%! can_switch_user(Options) is det.
%
% Verify the user options before forking, so we can print the
% message in time.
can_switch_user(Options) :-
option(user(User), Options),
!,
verify_root(switch_user(User)).
can_switch_user(_Options) :-
verify_no_root.
verify_root(_Task) :-
geteuid(0),
!.
verify_root(Task) :-
print_message(error, http_daemon(no_root(Task))),
halt(1).
verify_no_root :-
geteuid(0),
!,
throw(error(permission_error(open, server, http),
context('Refusing to run HTTP server as root', _))).
verify_no_root.
:- if(\+current_predicate(prctl/1)).
prctl(_).
:- endif.
%! server_redirect(+To, +Request)
%
% Redirect al requests for this server to the specified server. To
% is one of:
%
% $ A port (integer) :
% Redirect to the server running on that port in the same
% Prolog process.
% $ =true= :
% Results from just passing =|--redirect|=. Redirects to
% an HTTPS server in the same Prolog process.
% $ A URL :
% Redirect to the the given URL + the request uri. This can
% be used if the server cannot find its public address. For
% example:
%
% ```
% --http --redirect=https://myhost.org --https
% ```
server_redirect(Port, Request) :-
integer(Port),
http_server_property(Port, scheme(Scheme)),
http_public_host(Request, Host, _Port, []),
memberchk(request_uri(Location), Request),
( default_port(Scheme, Port)
-> format(string(To), '~w://~w~w', [Scheme, Host, Location])
; format(string(To), '~w://~w:~w~w', [Scheme, Host, Port, Location])
),
throw(http_reply(moved_temporary(To))).
server_redirect(true, Request) :-
!,
http_server_property(P, scheme(https)),
server_redirect(P, Request).
server_redirect(URI, Request) :-
memberchk(request_uri(Location), Request),
atom_concat(URI, Location, To),
throw(http_reply(moved_temporary(To))).
default_port(http, 80).
default_port(https, 443).
%! setup_debug(+Options) is det.
%
% Initialse debug/3 topics. The =|--debug|= option may be used
% multiple times.
setup_debug(Options) :-
setup_trace(Options),
nodebug(_),
debug(daemon),
enable_debug(Options).
enable_debug([]).
enable_debug([debug(Topic)|T]) :-
!,
atom_to_term(Topic, Term, _),
debug(Term),
enable_debug(T).
enable_debug([_|T]) :-
enable_debug(T).
setup_trace(Options) :-
option(gtrace(true), Options),
!,
gtrace.
setup_trace(_).
%! kill_x11(+Options) is det.
%
% Get rid of X11 access if interactive is false.
kill_x11(Options) :-
getenv('DISPLAY', Display),
Display \== '',
option(interactive(false), Options, false),
!,
setenv('DISPLAY', ''),
set_prolog_flag(gui, false).
kill_x11(_).
%! setup_signals(+Options)
%
% Prepare the server for signal handling. By default SIGINT and
% SIGTERM terminate the server. SIGHUP causes the server to run
% make/0.
setup_signals(Options) :-
option(interactive(true), Options, false),
!.
setup_signals(Options) :-
on_signal(int, _, quit),
on_signal(term, _, quit),
option(sighup(Action), Options, reload),
must_be(oneof([reload,quit]), Action),
on_signal(usr1, _, logrotate),
on_signal(hup, _, Action).
:- public
quit/1,
reload/1,
logrotate/1.
quit(Signal) :-
debug(daemon, 'Dying on signal ~w', [Signal]),
thread_send_message(main, quit).
reload(Signal) :-
debug(daemon, 'Reload on signal ~w', [Signal]),
thread_send_message(main, reload).
logrotate(Signal) :-
debug(daemon, 'Closing log files on signal ~w', [Signal]),
thread_send_message(main, logrotate).
%! wait(+Options)
%
% This predicate runs in the main thread, waiting for messages
% send by signal handlers to control the server. In addition, it
% broadcasts maintenance(Interval, Deadline) messages every
% Interval seconds. These messages may be trapped using listen/2
% for performing scheduled maintenance such as rotating log files,
% cleaning stale data, etc.
wait(Options) :-
option(interactive(true), Options, false),
!,
enable_development_system.
wait(Options) :-
thread_self(Me),
option(maintenance_interval(Interval), Options, 300),
Interval > 0,
!,
first_deadline(Interval, FirstDeadline),
State = deadline(0),
repeat,
State = deadline(Count),
Deadline is FirstDeadline+Count*Interval,
( thread_idle(thread_get_message(Me, Msg, [deadline(Deadline)]),
long)
-> catch(ignore(handle_message(Msg)), E,
print_message(error, E)),
Msg == quit,
catch(broadcast(http(shutdown)), E,
print_message(error, E)),
halt(0)
; Count1 is Count + 1,
nb_setarg(1, State, Count1),
catch(broadcast(maintenance(Interval, Deadline)), E,
print_message(error, E)),
fail
).
wait(_) :-
thread_self(Me),
repeat,
thread_idle(thread_get_message(Me, Msg), long),
catch(ignore(handle_message(Msg)), E,
print_message(error, E)),
Msg == quit,
!,
halt(0).
handle_message(reload) :-
make,
broadcast(logrotate).
handle_message(logrotate) :-
broadcast(logrotate).
first_deadline(Interval, Deadline) :-
get_time(Now),
Deadline is ((integer(Now) + Interval - 1)//Interval)*Interval.
/*******************************
* HOOKS *
*******************************/
%! http_server_hook(+Options) is semidet.
%
% Hook that is called to start the HTTP server. This hook must be
% compatible to http_server(Handler, Options). The default is
% provided by start_server/1.
%! http:sni_options(-HostName, -SSLOptions) is multi.
%
% Hook to provide Server Name Indication (SNI) for TLS
% servers. When starting an HTTPS server, all solutions of this
% predicate are collected and a suitable sni_hook/1 is defined
% for ssl_context/3 to use different contexts depending on the
% host name of the client request. This hook is executed
% _before_ privileges are dropped.
/*******************************
* MESSAGES *
*******************************/
:- multifile
prolog:message//1.
prolog:message(http_daemon(help)) -->
[ 'Usage: <program> option ...'-[], nl,
'Options:'-[], nl, nl,
' --port=port HTTP port to listen to'-[], nl,
' --ip=IP Only listen to this ip (--ip=localhost)'-[], nl,
' --debug=topic Print debug message for topic'-[], nl,
' --syslog=ident Send output to syslog daemon as ident'-[], nl,
' --user=user Run server under this user'-[], nl,
' --group=group Run server under this group'-[], nl,
' --pidfile=path Write PID to path'-[], nl,
' --output=file Send output to file (instead of syslog)'-[], nl,
' --fork=bool Do/do not fork'-[], nl,
' --http[=Address] Create HTTP server'-[], nl,
' --https[=Address] Create HTTPS server'-[], nl,
' --certfile=file The server certificate'-[], nl,
' --keyfile=file The server private key'-[], nl,
' --pwfile=file File holding password for the private key'-[], nl,
' --password=pw Password for the private key'-[], nl,
' --cipherlist=cs Cipher strings separated by colons'-[], nl,
' --redirect=to Redirect all requests to a URL or port'-[], nl,
' --interactive=bool Enter Prolog toplevel after starting server'-[], nl,
' --gtrace=bool Start (graphical) debugger'-[], nl,
' --sighup=action Action on SIGHUP: reload (default) or quit'-[], nl,
' --workers=count Number of HTTP worker threads'-[], nl,
' --timeout=sec Time to wait for client to complete request'-[], nl,
' --keep_alive_timeout=sec'-[], nl,
' Time to wait for a new request'-[], nl,
nl,
'Boolean options may be written without value (true) or as --no-name (false)'-[], nl,
'Address is a port number or host:port, e.g., 8080 or localhost:8080'-[], nl,
'Multiple servers can be started by repeating --http and --https'-[], nl,
'Each server merges the options before the first --http(s) and up the next'-[]
].
prolog:message(http_daemon(no_root(switch_user(User)))) -->
[ 'Program must be started as root to use --user=~w.'-[User] ].
prolog:message(http_daemon(no_root(open_port(Port)))) -->
[ 'Cannot open port ~w. Only root can open ports below 1000.'-[Port] ].
|