Bump liberty, make use of its new asciiman.awk

xP: use a dotted border for button focus
It's visible enough.
2022-09-25 21:02:51 +02:00 · 2022-09-25 11:08:50 +02:00 · 2022-09-23 20:35:56 +02:00 · 2022-09-23 19:00:31 +02:00 · 2022-09-23 19:00:31 +02:00 · 2022-09-23 09:42:24 +02:00
38 changed files with 6315 additions and 905 deletions
--- a/.clang-format
+++ b/.clang-format
@@ -0,0 +1,32 @@
+# clang-format is fairly limited, and these rules are approximate:
+#  - array initializers can get terribly mangled with clang-format 12.0,
+#  - sometimes it still aligns with space characters,
+#  - struct name NL { NL ... NL } NL name; is unachievable.
+BasedOnStyle: GNU
+ColumnLimit: 80
+IndentWidth: 4
+TabWidth: 4
+UseTab: ForContinuationAndIndentation
+BreakBeforeBraces: Allman
+SpaceAfterCStyleCast: true
+AlignAfterOpenBracket: DontAlign
+AlignOperands: DontAlign
+AlignConsecutiveMacros: Consecutive
+AllowAllArgumentsOnNextLine: false
+AllowAllParametersOfDeclarationOnNextLine: false
+IndentGotoLabels: false
+
+# IncludeCategories has some potential, but it may also break the build.
+# Note that the documentation says the value should be "Never".
+SortIncludes: false
+
+# This is a compromise, it generally works out aesthetically better.
+BinPackArguments: false
+
+# Unfortunately, this can't be told to align to column 40 or so.
+SpacesBeforeTrailingComments: 2
+
+# liberty-specific macro body wrappers.
+MacroBlockBegin: "BLOCK_START"
+MacroBlockEnd: "BLOCK_END"
+ForEachMacros: ["LIST_FOR_EACH"]
--- a/.gitignore
+++ b/.gitignore
@@ -3,7 +3,9 @@

 # Qt Creator files
 /CMakeLists.txt.user*
-/uirc3.config
-/uirc3.files
-/uirc3.creator*
-/uirc3.includes
+/xK.config
+/xK.files
+/xK.creator*
+/xK.includes
+/xK.cflags
+/xK.cxxflags
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,15 +1,21 @@
-cmake_minimum_required (VERSION 3.0)
-project (uirc3 VERSION 1.3.0 LANGUAGES C)
+# Ubuntu 18.04 LTS and OpenBSD 6.4
+cmake_minimum_required (VERSION 3.10)
+project (xK VERSION 1.5.0
+	DESCRIPTION "IRC daemon, bot, TUI client and its web frontend" LANGUAGES C)

 # Options
 option (WANT_READLINE "Use GNU Readline for the UI (better)" ON)
 option (WANT_LIBEDIT "Use BSD libedit for the UI" OFF)
+option (WANT_XF "Build xF" OFF)

 # Moar warnings
+set (CMAKE_C_STANDARD 99)
+set (CMAKE_C_STANDARD_REQUIRED ON)
+set (CMAKE_C_EXTENSIONS OFF)
+
 if ("${CMAKE_C_COMPILER_ID}" MATCHES "GNU" OR CMAKE_COMPILER_IS_GNUCC)
 	# -Wunused-function is pretty annoying here, as everything is static
-	set (wdisabled "-Wno-unused-function")
-	set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=c99 -Wall -Wextra ${wdisabled}")
+	set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -Wno-unused-function")
 endif ()

 # Version
@@ -57,6 +63,8 @@ if ("${CMAKE_SYSTEM_NAME}" MATCHES "BSD")
 	# Need this for SIGWINCH in FreeBSD and OpenBSD respectively;
 	# our POSIX version macros make it undefined
 	add_definitions (-D__BSD_VISIBLE=1 -D_BSD_SOURCE=1)
+elseif (APPLE)
+	add_definitions (-D_DARWIN_C_SOURCE)
 endif ()

 # -lrt is only for glibc < 2.17
@@ -112,10 +120,16 @@ endif ()
 if ((WANT_READLINE AND WANT_LIBEDIT) OR (NOT WANT_READLINE AND NOT WANT_LIBEDIT))
 	message (SEND_ERROR "You have to choose either GNU Readline or libedit")
 elseif (WANT_READLINE)
+	pkg_check_modules (readline readline)
+
 	# OpenBSD's default readline is too old
 	if ("${CMAKE_SYSTEM_NAME}" MATCHES "OpenBSD")
 		include_directories (${OPENBSD_LOCALBASE}/include/ereadline)
 		list (APPEND xC_libraries ereadline)
+	elseif (readline_FOUND)
+		list (APPEND xC_libraries ${readline_LIBRARIES})
+		include_directories (${readline_INCLUDE_DIRS})
+		link_directories (${readline_LIBRARY_DIRS})
 	else ()
 		list (APPEND xC_libraries readline)
 	endif ()
@@ -131,28 +145,55 @@ set (HAVE_EDITLINE "${WANT_LIBEDIT}")
 set (HAVE_LUA      "${WITH_LUA}")

 include (GNUInstallDirs)
-configure_file (${PROJECT_SOURCE_DIR}/config.h.in ${PROJECT_BINARY_DIR}/config.h)
+set (project_config ${PROJECT_BINARY_DIR}/config.h)
+configure_file (${PROJECT_SOURCE_DIR}/config.h.in ${project_config})
 include_directories (${PROJECT_SOURCE_DIR} ${PROJECT_BINARY_DIR})

 # Generate IRC replies--we need a custom target because of the multiple outputs
 add_custom_command (OUTPUT xD-replies.c xD.msg
-	COMMAND ${PROJECT_SOURCE_DIR}/xD-gen-replies.sh
-		> xD-replies.c < ${PROJECT_SOURCE_DIR}/xD-replies
-	DEPENDS ${PROJECT_SOURCE_DIR}/xD-replies
+	COMMAND env LC_ALL=C awk
+		-f ${PROJECT_SOURCE_DIR}/xD-gen-replies.awk
+		${PROJECT_SOURCE_DIR}/xD-replies > xD-replies.c
+	DEPENDS
+		${PROJECT_SOURCE_DIR}/xD-gen-replies.awk
+		${PROJECT_SOURCE_DIR}/xD-replies
 	COMMENT "Generating files from the list of server numerics")
 add_custom_target (replies DEPENDS ${PROJECT_BINARY_DIR}/xD-replies.c)

+add_custom_command (OUTPUT xC-proto.c
+	COMMAND env LC_ALL=C awk
+		-f ${PROJECT_SOURCE_DIR}/xC-gen-proto.awk
+		-f ${PROJECT_SOURCE_DIR}/xC-gen-proto-c.awk
+		${PROJECT_SOURCE_DIR}/xC-proto > xC-proto.c
+	DEPENDS
+		${PROJECT_SOURCE_DIR}/xC-gen-proto.awk
+		${PROJECT_SOURCE_DIR}/xC-gen-proto-c.awk
+		${PROJECT_SOURCE_DIR}/xC-proto
+	COMMENT "Generating xC relay protocol code")
+add_custom_target (xC-proto DEPENDS ${PROJECT_BINARY_DIR}/xC-proto.c)
+
 # Build
 foreach (name xB xC xD)
-	add_executable (${name} ${name}.c ${PROJECT_BINARY_DIR}/config.h)
+	add_executable (${name} ${name}.c ${project_config})
 	target_link_libraries (${name} ${project_libraries})
 	add_threads (${name})
 endforeach ()

 add_dependencies (xD replies)
-add_dependencies (xC replies)
+add_dependencies (xC replies xC-proto)
 target_link_libraries (xC ${xC_libraries})

+if (WANT_XF)
+	pkg_check_modules (x11 REQUIRED x11 xrender xft fontconfig)
+	include_directories (${x11_INCLUDE_DIRS})
+	link_directories (${x11_LIBRARY_DIRS})
+
+	add_executable (xF xF.c ${project_config})
+	add_dependencies (xF xC-proto)
+	target_link_libraries (xF ${x11_LIBRARIES} ${project_libraries})
+	add_threads (xF)
+endif ()
+
 # Tests
 include (CTest)
 if (BUILD_TESTING)
@@ -184,7 +225,6 @@ add_custom_target (clang-tidy
 # Installation
 install (TARGETS xB xC xD DESTINATION ${CMAKE_INSTALL_BINDIR})
 install (FILES LICENSE DESTINATION ${CMAKE_INSTALL_DOCDIR})
-# XXX: our defaults for XDG_DATA_DIRS expect /usr/local/shore or /usr/share
 install (DIRECTORY plugins/xB/
 	DESTINATION ${CMAKE_INSTALL_DATADIR}/xB/plugins USE_SOURCE_PERMISSIONS)
 install (DIRECTORY plugins/xC/
@@ -192,20 +232,39 @@ install (DIRECTORY plugins/xC/

 # Generate documentation from text markup
 find_program (ASCIIDOCTOR_EXECUTABLE asciidoctor)
-if (NOT ASCIIDOCTOR_EXECUTABLE)
-	message (FATAL_ERROR "asciidoctor not found")
+find_program (A2X_EXECUTABLE a2x)
+if (NOT ASCIIDOCTOR_EXECUTABLE AND NOT A2X_EXECUTABLE)
+	message (WARNING "Neither asciidoctor nor a2x were found, "
+		"falling back to a substandard manual page generator")
 endif ()

 foreach (page xB xC xD)
 	set (page_output "${PROJECT_BINARY_DIR}/${page}.1")
 	list (APPEND project_MAN_PAGES "${page_output}")
-	add_custom_command (OUTPUT ${page_output}
-		COMMAND ${ASCIIDOCTOR_EXECUTABLE} -b manpage
-			-a release-version=${project_version}
-			"${PROJECT_SOURCE_DIR}/${page}.adoc"
-			-o "${page_output}"
-		DEPENDS ${page}.adoc
-		COMMENT "Generating man page for ${page}" VERBATIM)
+	if (ASCIIDOCTOR_EXECUTABLE)
+		add_custom_command (OUTPUT ${page_output}
+			COMMAND ${ASCIIDOCTOR_EXECUTABLE} -b manpage
+				-a release-version=${project_version}
+				-o "${page_output}"
+				"${PROJECT_SOURCE_DIR}/${page}.adoc"
+			DEPENDS ${page}.adoc
+			COMMENT "Generating man page for ${page}" VERBATIM)
+	elseif (A2X_EXECUTABLE)
+		add_custom_command (OUTPUT ${page_output}
+			COMMAND ${A2X_EXECUTABLE} --doctype manpage --format manpage
+				-a release-version=${project_version}
+				-D "${PROJECT_BINARY_DIR}"
+				"${PROJECT_SOURCE_DIR}/${page}.adoc"
+			DEPENDS ${page}.adoc
+			COMMENT "Generating man page for ${page}" VERBATIM)
+	else ()
+		set (ASCIIMAN ${PROJECT_SOURCE_DIR}/liberty/tools/asciiman.awk)
+		add_custom_command (OUTPUT ${page_output}
+			COMMAND env LC_ALL=C awk -f ${ASCIIMAN}
+				"${PROJECT_SOURCE_DIR}/${page}.adoc" > ${page_output}
+			DEPENDS ${page}.adoc ${ASCIIMAN}
+			COMMENT "Generating man page for ${page}" VERBATIM)
+	endif ()
 endforeach ()

 add_custom_target (docs ALL DEPENDS ${project_MAN_PAGES})
@@ -217,7 +276,6 @@ foreach (page ${project_MAN_PAGES})
 endforeach ()

 # CPack
-set (CPACK_PACKAGE_DESCRIPTION_SUMMARY "Unreasonable IRC client, daemon and bot")
 set (CPACK_PACKAGE_VERSION "${project_version_safe}")
 set (CPACK_PACKAGE_VENDOR "Premysl Eric Janouch")
 set (CPACK_PACKAGE_CONTACT "Přemysl Eric Janouch <p@janouch.name>")
--- a/2
+++ b/2
@@ -1,4 +1,4 @@
-Copyright (c) 2014 - 2021, Přemysl Eric Janouch <p@janouch.name>
+Copyright (c) 2014 - 2022, Přemysl Eric Janouch <p@janouch.name>

 Permission to use, copy, modify, and/or distribute this software for any
 purpose with or without fee is hereby granted.
--- a/59
+++ b/59
@@ -1,3 +1,62 @@
+2.0.0 (Unreleased)
+
+ * xD: implemented WALLOPS, choosing to make it target even non-operators
+
+ * xC: made it show WALLOPS messages, as PRIVMSG for the server buffer
+
+ * xC: all behaviour.* configuration options have been renamed to general.*,
+   with the exception of editor_command/editor, backlog_helper/pager,
+   and backlog_helper_strip_formatting/pager_strip_formatting
+
+ * xC: all attributes.* configuration options have been made abstract in
+   a subset of the git-config(1) format, and renamed to theme.*,
+   with the exception of attributes.reset, which has no replacement
+
+ * xC: replaced behaviour.save_on_quit with general.autosave
+
+ * xC: improved pager integration capabilities
+
+ * xC: unsolicited JOINs will no longer automatically activate the buffer
+
+ * xC: made Readline insert the longest common completion prefix first,
+   and prevented the possible-completions command from duplicating the prompt
+
+ * xC: normalized editline's history behaviour, making it a viable frontend
+
+ * xC: various bugfixes
+
+ * xC: added a relay interface, enabled through the general.relay_bind option
+
+ * Added a web frontend for xC called xP
+
+
+1.5.0 (2021-12-21) "The Show Must Go On"
+
+ * xC: made it possible to pass the cursor position to external editors,
+   in particular VIM and Emacs
+
+ * xC: started quoting text coming from bracketed pastes,
+   to minimize the risk of trying to execute filesystem paths as commands
+
+ * xC: fixed to work with post-2021-08-29 editline
+
+ * xC: extended editline's autocomplete to show all options
+
+ * utm-filter.lua: added Facebook's tracking parameter to the filter
+
+
+1.4.0 (2021-10-06) "Call Me Scruffy Scruffington"
+
+ * xC: made message autosplitting respect text formatting
+
+ * xC: fixed displaying IRC colours above 16
+
+ * xC: offer IRCnet as an IRC network to connect to,
+   rather than the lunatic new Freenode
+
+ * xD: started bumping the soft limit on file descriptors to the hard one
+
+
 1.3.0 (2021-08-07) "New World Order"

 * xC: made nick autocompletion offer recent speakers first
--- a/README.adoc
+++ b/README.adoc
@@ -1,73 +1,65 @@
-uirc3
-=====
-:compact-option:
+xK
+==

-The unreasonable IRC trinity.  This project consists of an IRC client, daemon,
-and bot.  It's all you're ever going to need for chatting, as long as you can
-make do with minimalist software.
+'xK' (chat kit) is an IRC software suite consisting of a daemon, bot, terminal
+client, and a web frontend for the client.  It's all you're ever going to
+need for chatting, so long as you can make do with slightly minimalist software.

-All of them have these potentially interesting properties:
-
- - IPv6 support
- - TLS support, including client certificates
- - lean on dependencies (with the exception of 'xC')
- - compact and arguably easy to hack on
- - very permissive license
+They're all lean on dependencies, and offer a maximally permissive licence.

 xC
 --
-The IRC client.  It is largely defined by being built on top of GNU Readline
-that has been hacked to death.  Its interface should feel somewhat familiar for
-weechat or irssi users.
+The IRC client, and the core of 'xK'.  It is largely defined by building on top
+of GNU Readline or BSD Editline that have been hacked to death.  Its interface
+should feel somewhat familiar for weechat or irssi users.

-image::xC.png[align="center"]
+image::xC.webp[align="center"]

-This is the largest application within the project.  It has most of the stuff
-you'd expect of an IRC client, such as being able to set up multiple servers,
-a powerful configuration system, integrated help, text formatting, CTCP queries,
-automatic splitting of overlong messages, autocomplete, logging to file,
-auto-away, command aliases and basic support for Lua scripting.
+It has most features you'd expect of an IRC client, such as being multiserver,
+a powerful configuration system, integrated help, text formatting, automatic
+message splitting, multiline editing, bracketed paste support, word wrapping
+that doesn't break links, autocomplete, logging, CTCP queries, auto-away,
+command aliases, SOCKS proxying, SASL EXTERNAL authentication using TLS client
+certificates, a remote relay interface, or basic support for Lua scripting.
+As a unique bonus, you can launch a full text editor from within.
+
+xP
+--
+The web frontend for 'xC', making use of its networked relay interface.
+It intentionally differs in that it uses a sans-serif font, and it shows
+the list of all buffers in a side panel.  Otherwise it is a near replica,
+including link:xC.adoc#_key_bindings[keyboard shortcuts].
+
+image::xP.webp[align="center"]

 xD
 --
-The IRC daemon.  It is designed to be used as a regular user application rather
-than a system-wide daemon.  If all you want is a decent, minimal IRCd for
-testing purposes or a small network of respectful users (or bots), this one will
-do it just fine.
+The IRC daemon.  It is designed for use as a regular user application rather
+than a system-wide daemon, and follows the XDG Base Directory Specification.
+If all you want is a decent, minimal IRCd for testing purposes or a small
+network of respectful users (or bots), this one will do it just fine.

-Notable features:
+It autodetects TLS on incoming connections (I'm still wondering why everyone
+doesn't have this), authenticates operators via TLS client certificate
+fingerprints, and supports a number of IRCv3 capabilities.

- - TLS autodetection (why doesn't everyone have this?), using secure defaults
- - IRCop authentication via TLS client certificates
- - epoll/kqueue support; this means that it should be able to handle quite
-   a number of concurrent user connections
- - partial IRCv3 support
+What it notably doesn't support is online changes to configuration, any limits
+besides the total number of connections and mode `+l`, or server linking
+(which also means no services).

-Not supported:
-
- - server linking (which also means no services); I consider existing protocols
-   for this purpose ugly and tricky to implement correctly; I've also found no
-   use for this feature yet
- - online changes to configuration; the configuration system from 'xC' could
-   be used to implement this feature if needed
- - limits of almost any kind, just connections and mode `+l`
-
-This program has been
-https://git.janouch.name/p/haven/src/branch/master/hid[ported to Go],
-and development continues over there.
+This program has been https://git.janouch.name/p/haven/src/branch/master/hid[
+ported to Go] in a different project, and development continues over there.

 xB
 --
-The IRC bot.  It builds upon the concept of my other VitaminA IRC bot.  The main
-characteristic of these two bots is that they run plugins as coprocesses, which
-allows for enhanced reliability and programming language freedom.
+The IRC bot.  While originally intended to be a simple rewrite of my old GNU AWK
+bot in C, it fairly quickly became a playground, and it eventually got me into
+writing the rest of this package.

-While originally intended to be a simple rewrite of the original AWK bot in C,
-it fairly quickly became a playground, and it eventually got me into writing
-the rest of the package.
-
-It survives crashes, server disconnects and timeouts, and also has native SOCKS
-support (even though socksify can add that easily to any program).
+Its main characteristic is that it runs plugins as coprocesses, allowing for
+enhanced reliability and programming language freedom.  Moreover, it recovers
+from any crashes, and offers native SOCKS support (even though socksify can add
+that easily to any program).

 Packages
 --------
@@ -76,29 +68,27 @@ a package with the latest development version from Archlinux's AUR.

 Building
 --------
-Build dependencies: CMake, pkg-config, asciidoctor, awk, liberty (included) +
-Runtime dependencies: openssl +
-Additionally for 'xC': curses, libffi, lua >= 5.3 (optional),
-                       readline >= 6.0 or libedit >= 2013-07-12
+Build-only dependencies: CMake, pkg-config, awk, liberty (included),
+ asciidoctor or asciidoc (recommended but optional) +
+Common runtime dependencies: openssl +
+Additionally for 'xC': curses, libffi, readline >= 6.0 or libedit >= 2013-07-12,
+ lua >= 5.3 (optional) +

-Avoid libedit if you can, in general it works but at the moment history is
-acting up and I have no clue about fixing it.
-
- $ git clone --recursive https://git.janouch.name/p/uirc3.git
- $ mkdir uirc3/build
- $ cd uirc3/build
- $ cmake .. -DCMAKE_INSTALL_PREFIX=/usr -DCMAKE_BUILD_TYPE=Debug \
-            -DWANT_READLINE=ON -DWANT_LIBEDIT=OFF -DWANT_LUA=ON
+ $ git clone --recursive https://git.janouch.name/p/xK.git
+ $ mkdir xK/build
+ $ cd xK/build
+ $ cmake .. -DCMAKE_INSTALL_PREFIX=/usr -DCMAKE_BUILD_TYPE=RelWithDebInfo \
+            -DWANT_READLINE=ON -DWANT_LIBEDIT=OFF -DWITH_LUA=ON
 $ make

 To install the application, you can do either the usual:

 # make install

-Or you can try telling CMake to make a package for you.  For Debian it is:
+Or you can try telling CMake to make a package for you:

- $ cpack -G DEB
- # dpkg -i uirc3-*.deb
+ $ cpack -G DEB  # also supported: RPM, FreeBSD
+ # dpkg -i xK-*.deb

 Usage
 -----
@@ -123,6 +113,23 @@ a Screen or tmux session.
 file or something like `killall` if you want to terminate it.  You can run it
 as a `forking` type systemd user service.

+xP
+~~
+The precondition for running 'xC' frontends is enabling its relay interface:
+
+ /set general.relay_bind = "127.0.0.1:9000"
+
+To build the web server, you'll need to install the Go compiler, and run `make`
+from the _xP_ directory.  Then start it from the _public_ subdirectory,
+and navigate to the adress you gave it as its first argument--in the following
+example, that would be http://localhost:8080[]:
+
+ $ ../xP 127.0.0.1:8080 127.0.0.1:9000
+
+For remote use, it's recommended to put 'xP' behind a reverse proxy, with TLS,
+and some form of HTTP authentication.  Pass the external URL of the WebSocket
+endpoint as the third command line argument in this case.
+
 Client Certificates
 -------------------
 'xC' will use the SASL EXTERNAL method to authenticate using the TLS client
@@ -156,20 +163,24 @@ Beware that you can easily break the program if you're not careful.

 How do I make xC look like the screenshot?
 ------------------------------------------
-First of all, you must build it with Lua support.  With the defaults, 'xC'
-doesn't look too fancy because I don't want to depend on Lua or 256-colour
-terminals.  In addition to that, I appear to be one of the few people who use
-black on white terminals.
+With the defaults, 'xC' doesn't look too fancy because I don't want to have
+a hard dependency on either Lua for the bundled script that provides an easily
+adjustable enhanced prompt, or on 256-colour terminals.  Moreover, it's nearly
+impossible to come up with a colour theme that would work well with both
+black-on-white and white-on-black terminals, or anything wild in between.

- /set behaviour.date_change_line = "%a %e %b %Y"
- /set behaviour.plugin_autoload += "fancy-prompt.lua"
- /set behaviour.backlog_helper = "LESSSECURE=1 less -R +Gb1d -Ps'Backlog ?ltlines %lt-%lb?L/%L. .?e(END):?pB%pB\\%..'"
- /set attributes.userhost = "\x1b[38;5;109m"
- /set attributes.join = "\x1b[38;5;108m"
- /set attributes.part = "\x1b[38;5;138m"
- /set attributes.external = "\x1b[38;5;248m"
- /set attributes.timestamp = "\x1b[48;5;255m\x1b[38;5;250m"
- /set attributes.read_marker = "\x1b[38;5;202m"
+Assuming that your build supports Lua plugins, and that you have a decent,
+properly set-up terminal emulator, it suffices to run:
+
+ /set general.pager = Press Tab here and change +Gb to +Gb1d
+ /set general.date_change_line = "%a %e %b %Y"
+ /set general.plugin_autoload += "fancy-prompt.lua"
+ /set theme.userhost = "109"
+ /set theme.join = "108"
+ /set theme.part = "138"
+ /set theme.external = "248"
+ /set theme.timestamp = "250 255"
+ /set theme.read_marker = "202"

 Configuration profiles
 ----------------------
@@ -184,7 +195,7 @@ configurations accordingly, but I consider it rather messy and unnecessary.

 Contributing and Support
 ------------------------
-Use https://git.janouch.name/p/uirc3 to report any bugs, request features,
+Use https://git.janouch.name/p/xK to report any bugs, request features,
 or submit pull requests.  `git send-email` is tolerated.  If you want to discuss
 the project, feel free to join me at ircs://irc.janouch.name, channel #dev.

--- a/common.c
+++ b/common.c
@@ -1,7 +1,7 @@
 /*
 * common.c: common functionality
 *
- * Copyright (c) 2014 - 2020, Přemysl Eric Janouch <p@janouch.name>
+ * Copyright (c) 2014 - 2022, Přemysl Eric Janouch <p@janouch.name>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted.
@@ -22,11 +22,11 @@
 #define LIBERTY_WANT_PROTO_IRC

 #ifdef WANT_SYSLOG_LOGGING
-	#define print_fatal_data    ((void *) LOG_ERR)
-	#define print_error_data    ((void *) LOG_ERR)
-	#define print_warning_data  ((void *) LOG_WARNING)
-	#define print_status_data   ((void *) LOG_INFO)
-	#define print_debug_data    ((void *) LOG_DEBUG)
+#define print_fatal_data    ((void *) LOG_ERR)
+#define print_error_data    ((void *) LOG_ERR)
+#define print_warning_data  ((void *) LOG_WARNING)
+#define print_status_data   ((void *) LOG_INFO)
+#define print_debug_data    ((void *) LOG_DEBUG)
 #endif // WANT_SYSLOG_LOGGING

 #include "liberty/liberty.c"
@@ -48,6 +48,66 @@ init_openssl (void)
 #endif
 }

+static char *
+gai_reconstruct_address (struct addrinfo *ai)
+{
+	char host[NI_MAXHOST] = {}, port[NI_MAXSERV] = {};
+	int err = getnameinfo (ai->ai_addr, ai->ai_addrlen,
+		host, sizeof host, port, sizeof port,
+		NI_NUMERICHOST | NI_NUMERICSERV);
+	if (err)
+	{
+		print_debug ("%s: %s", "getnameinfo", gai_strerror (err));
+		return xstrdup ("?");
+	}
+	return format_host_port_pair (host, port);
+}
+
+static bool
+accept_error_is_transient (int err)
+{
+	// OS kernels may return a wide range of unforeseeable errors.
+	// Assuming that they're either transient or caused by
+	// a connection that we've just extracted from the queue.
+	switch (err)
+	{
+	case EBADF:
+	case EINVAL:
+	case ENOTSOCK:
+	case EOPNOTSUPP:
+		return false;
+	default:
+		return true;
+	}
+}
+
+/// Destructively tokenize an address into a host part, and a port part.
+/// The port is only overwritten if that part is found, allowing for defaults.
+static const char *
+tokenize_host_port (char *address, const char **port)
+{
+	// Unwrap IPv6 addresses in format_host_port_pair() format.
+	char *rbracket = strchr (address, ']');
+	if (*address == '[' && rbracket)
+	{
+		if (rbracket[1] == ':')
+		{
+			*port = rbracket + 2;
+			return *rbracket = 0, address + 1;
+		}
+		if (!rbracket[1])
+			return *rbracket = 0, address + 1;
+	}
+
+	char *colon = strchr (address, ':');
+	if (colon)
+	{
+		*port = colon + 1;
+		return *colon = 0, address;
+	}
+	return address;
+}
+
 // --- To be moved to liberty --------------------------------------------------

 // FIXME: in xssl_get_error() we rely on error reasons never being NULL (i.e.,
@@ -74,6 +134,15 @@ xerr_describe_error (void)
 	return reason;
 }

+static struct str
+str_from_cstr (const char *cstr)
+{
+	struct str self;
+	self.alloc = (self.len = strlen (cstr)) + 1;
+	self.str = memcpy (xmalloc (self.alloc), cstr, self.alloc);
+	return self;
+}
+
 static ssize_t
 strv_find (const struct strv *v, const char *s)
 {
@@ -87,15 +156,15 @@ static time_t
 unixtime_msec (long *msec)
 {
 #ifdef _POSIX_TIMERS
-        struct timespec tp;
-        hard_assert (clock_gettime (CLOCK_REALTIME, &tp) != -1);
-        *msec = tp.tv_nsec / 1000000;
+	struct timespec tp;
+	hard_assert (clock_gettime (CLOCK_REALTIME, &tp) != -1);
+	*msec = tp.tv_nsec / 1000000;
 #else // ! _POSIX_TIMERS
-        struct timeval tp;
-        hard_assert (gettimeofday (&tp, NULL) != -1);
-        *msec = tp.tv_usec / 1000;
+	struct timeval tp;
+	hard_assert (gettimeofday (&tp, NULL) != -1);
+	*msec = tp.tv_usec / 1000;
 #endif // ! _POSIX_TIMERS
-        return tp.tv_sec;
+	return tp.tv_sec;
 }

 // --- Logging -----------------------------------------------------------------
@@ -260,7 +329,7 @@ struct socks_connector

 SOCKS_DATA_CB (socks_4a_finish)
 {
-	uint8_t null, status;
+	uint8_t null = 0, status = 0;
 	hard_assert (msg_unpacker_u8 (unpacker, &null));
 	hard_assert (msg_unpacker_u8 (unpacker, &status));

@@ -363,7 +432,7 @@ SOCKS_DATA_CB (socks_5_request_domain)

 SOCKS_DATA_CB (socks_5_request_finish)
 {
-	uint8_t version, status, reserved, type;
+	uint8_t version = 0, status = 0, reserved = 0, type = 0;
 	hard_assert (msg_unpacker_u8 (unpacker, &version));
 	hard_assert (msg_unpacker_u8 (unpacker, &status));
 	hard_assert (msg_unpacker_u8 (unpacker, &reserved));
@@ -440,7 +509,7 @@ socks_5_request_start (struct socks_connector *self)

 SOCKS_DATA_CB (socks_5_userpass_finish)
 {
-	uint8_t version, status;
+	uint8_t version = 0, status = 0;
 	hard_assert (msg_unpacker_u8 (unpacker, &version));
 	hard_assert (msg_unpacker_u8 (unpacker, &status));

@@ -475,7 +544,7 @@ socks_5_userpass_start (struct socks_connector *self)

 SOCKS_DATA_CB (socks_5_auth_finish)
 {
-	uint8_t version, method;
+	uint8_t version = 0, method = 0;
 	hard_assert (msg_unpacker_u8 (unpacker, &version));
 	hard_assert (msg_unpacker_u8 (unpacker, &method));

--- a/config.h.in
+++ b/config.h.in
@@ -3,6 +3,9 @@

 #define PROGRAM_VERSION "${project_version}"

+// We use the XDG Base Directory Specification, but may be installed anywhere.
+#define PROJECT_DATADIR "${CMAKE_INSTALL_FULL_DATADIR}"
+
 #cmakedefine HAVE_READLINE
 #cmakedefine HAVE_EDITLINE
 #cmakedefine HAVE_LUA
--- a/2
+++ b/2
--- a/plugins/xC/fancy-prompt.lua
+++ b/plugins/xC/fancy-prompt.lua
@@ -1,7 +1,7 @@
 --
 -- fancy-prompt.lua: the fancy multiline prompt you probably want
 --
-- Copyright (c) 2016, Přemysl Eric Janouch <p@janouch.name>
+-- Copyright (c) 2016 - 2022, Přemysl Eric Janouch <p@janouch.name>
 --
 -- Permission to use, copy, modify, and/or distribute this software for any
 -- purpose with or without fee is hereby granted.
@@ -40,7 +40,7 @@ xC.hook_prompt (function (hook)
 		if buffer == current then
 			current_n = i
 		elseif buffer.new_messages_count ~= buffer.new_unimportant_count then
-			if active ~= "" then active = active .. "," end
+			active = active .. ","
 			if buffer.highlighted then
 				active = active .. "!"
 				bg_color = "224"
@@ -48,7 +48,6 @@ xC.hook_prompt (function (hook)
 			active = active .. i
 		end
 	end
-	if active ~= "" then active = "(" .. active .. ")" end
 	local x = current_n .. ":" .. current.name
 	if chan and chan.users_len ~= 0 then
 		local params = ""
@@ -56,25 +55,34 @@ xC.hook_prompt (function (hook)
 			params = params .. " +" .. mode .. " " .. param
 		end
 		local modes = chan.no_param_modes .. params:sub (3)
-		if modes ~= "" then x = x .. "(+" .. modes .. ")" end
+		if modes ~= "" then
+			x = x .. "(+" .. modes .. ")"
+		end
 		x = x .. "{" .. chan.users_len .. "}"
 	end
-	if current.hide_unimportant then x = x .. "<H>" end
-
-	local lines, cols = xC.get_screen_size ()
-	x = x .. " " .. active .. string.rep (" ", cols)
+	if current.hide_unimportant then
+		x = x .. "<H>"
+	end
+	if active ~= "" then
+		x = x .. " (" .. active:sub (2) .. ")"
+	end

 	-- Readline 7.0.003 seems to be broken and completely corrupts the prompt.
 	-- However 8.0.004 seems to be fine with these, as is libedit 20191231-3.1.
 	--x = x:gsub("[\128-\255]", "?")

-	-- Cut off extra characters and apply formatting, including the hack.
-	-- FIXME: this doesn't count with full-width or zero-width characters.
-	--   We might want to export wcwidth() above term_from_utf8 somehow.
-	local overflow = utf8.offset (x, cols - 1)
-	if overflow then x = x:sub (1, overflow) end
+	-- Align to the terminal's width and apply formatting, including the hack.
+	local lines, cols = xC.get_screen_size ()
+	local trailing, width = " ", xC.measure (x)
+	while cols > 0 and width >= cols do
+		x = x:sub (1, utf8.offset (x, -1) - 1)
+		trailing, width = ">", xC.measure (x)
+	end
+
 	x = "\x01\x1b[0;4;1;38;5;16m\x1b[48;5;" .. bg_color .. "m\x02" ..
-		x ..  "\x01\x1b[0;4;1;7;38;5;" .. bg_color .. "m\x02 \x01\x1b[0;1m\x02"
+		x .. string.rep (" ", cols - width - 1) ..
+		"\x01\x1b[0;4;1;7;38;5;" .. bg_color .. "m\x02" ..
+		trailing .. "\x01\x1b[0;1m\x02"

 	local user_prefix = function (chan, user)
 		for i, chan_user in ipairs (chan.users) do
--- a/plugins/xC/utm-filter.lua
+++ b/plugins/xC/utm-filter.lua
@@ -1,7 +1,7 @@
 --
-- utm-filter.lua: filter out Google Analytics bullshit from URLs
+-- utm-filter.lua: filter out Google Analytics bullshit etc. from URLs
 --
-- Copyright (c) 2015, Přemysl Eric Janouch <p@janouch.name>
+-- Copyright (c) 2015 - 2021, Přemysl Eric Janouch <p@janouch.name>
 --
 -- Permission to use, copy, modify, and/or distribute this software for any
 -- purpose with or without fee is hereby granted.
@@ -19,6 +19,10 @@
 local banned = {
 	gclid        = 1,

+	-- Alas, Facebook no longer uses this parameter, see:
+	-- https://news.ycombinator.com/item?id=32117489
+	fbclid       = 1,
+
 	utm_source   = 1,
 	utm_medium   = 1,
 	utm_term     = 1,
--- a/xB.adoc
+++ b/xB.adoc
@@ -1,8 +1,8 @@
 xB(1)
 =====
 :doctype: manpage
-:manmanual: uirc3 Manual
-:mansource: uirc3 {release-version}
+:manmanual: xK Manual
+:mansource: xK {release-version}

 Name
 ----
@@ -60,14 +60,14 @@ using the IRC protocol.  (Caveat: the standard C library doesn't automatically
 flush FILE streams for pipes on newlines.)  A special *XB* command is introduced
 for RPC, with the following subcommands:

-*XB get_config* _key_::
+*XB get_config* __key__::
 	Request the value of the given configuration option.  If no such option
 	exists, the value will be empty.  The response will be delivered in
 	the following format:
 +
-```
+....
 XB :value
-```
+....
 +
 This is particularly useful for retrieving the *prefix* string.

@@ -100,5 +100,5 @@ _/usr/share/xB/plugins/_::

 Reporting bugs
 --------------
-Use https://git.janouch.name/p/uirc3 to report bugs, request features,
+Use https://git.janouch.name/p/xK to report bugs, request features,
 or submit pull requests.
--- a/xB.c
+++ b/xB.c
@@ -1019,6 +1019,7 @@ plugin_resolve_relative_filename (const char *filename)
 {
 	struct strv paths = strv_make ();
 	get_xdg_data_dirs (&paths);
+	strv_append (&paths, PROJECT_DATADIR);
 	char *result = resolve_relative_filename_generic
 		(&paths, PROGRAM_NAME "/plugins/", filename);
 	strv_free (&paths);
--- a/xC-gen-proto-c.awk
+++ b/xC-gen-proto-c.awk
@@ -0,0 +1,325 @@
+# xC-gen-proto-c.awk: C backend for xC-gen-proto.awk.
+#
+# Copyright (c) 2022, Přemysl Eric Janouch <p@janouch.name>
+# SPDX-License-Identifier: 0BSD
+#
+# Neither *_new() nor *_destroy() functions are provided, because they'd only
+# be useful for top-levels, and are merely extra malloc()/free() calls.
+# Users are expected to reuse buffers.
+#
+# Similarly, no constructors are produced--those are easy to write manually.
+#
+# All arrays are deserialized zero-terminated, so u8<> and i8<> can be directly
+# used as C strings.
+#
+# All types must be able to dispose partially zero values going from the back,
+# i.e., in the reverse order of deserialization.
+
+function define_internal(name, ctype) {
+	Types[name] = "internal"
+	CodegenCType[name] = ctype
+}
+
+function define_int(shortname, ctype) {
+	define_internal(shortname, ctype)
+	CodegenSerialize[shortname] = \
+		"\tstr_pack_" shortname "(w, %s);\n"
+	CodegenDeserialize[shortname] = \
+		"\tif (!msg_unpacker_" shortname "(r, &%s))\n" \
+		"\t\treturn false;\n"
+}
+
+function define_sint(size) { define_int("i" size, "int" size "_t") }
+function define_uint(size) { define_int("u" size, "uint" size "_t") }
+
+function codegen_begin() {
+	define_sint("8")
+	define_sint("16")
+	define_sint("32")
+	define_sint("64")
+	define_uint("8")
+	define_uint("16")
+	define_uint("32")
+	define_uint("64")
+
+	define_internal("string", "struct str")
+	CodegenDispose["string"] = "\tstr_free(&%s);\n"
+	CodegenSerialize["string"] = \
+		"\tif (!proto_string_serialize(&%s, w))\n" \
+		"\t\treturn false;\n"
+	CodegenDeserialize["string"] = \
+		"\tif (!proto_string_deserialize(&%s, r))\n" \
+		"\t\treturn false;\n"
+
+	define_internal("bool", "bool")
+	CodegenSerialize["bool"] = \
+		"\tstr_pack_u8(w, !!%s);\n"
+	CodegenDeserialize["bool"] = \
+		"\t{\n" \
+		"\t\tuint8_t v = 0;\n" \
+		"\t\tif (!msg_unpacker_u8(r, &v))\n" \
+		"\t\t\treturn false;\n" \
+		"\t\t%s = !!v;\n" \
+		"\t}\n"
+
+	print "// This file directly depends on liberty.c, but doesn't include it."
+
+	print ""
+	print "static bool"
+	print "proto_string_serialize(const struct str *s, struct str *w) {"
+	print "\tif (s->len > UINT32_MAX)"
+	print "\t\treturn false;"
+	print "\tstr_pack_u32(w, s->len);"
+	print "\tstr_append_str(w, s);"
+	print "\treturn true;"
+	print "}"
+
+	print ""
+	print "static bool"
+	print "proto_string_deserialize(struct str *s, struct msg_unpacker *r) {"
+	print "\tuint32_t len = 0;"
+	print "\tif (!msg_unpacker_u32(r, &len))"
+	print "\t\treturn false;"
+	print "\tif (msg_unpacker_get_available(r) < len)"
+	print "\t\treturn false;"
+	print "\t*s = str_make();"
+	print "\tstr_append_data(s, r->data + r->offset, len);"
+	print "\tr->offset += len;"
+	print "\tif (!utf8_validate (s->str, s->len))"
+	print "\t\treturn false;"
+	print "\treturn true;"
+	print "}"
+}
+
+function codegen_constant(name, value) {
+	print ""
+	print "enum { " PrefixUpper name " = " value " };"
+}
+
+function codegen_enum_value(name, subname, value, cg) {
+	append(cg, "fields",
+		"\t" PrefixUpper toupper(cameltosnake(name)) "_" subname \
+		" = " value ",\n")
+}
+
+function codegen_enum(name, cg,    ctype) {
+	ctype = "enum " PrefixLower cameltosnake(name)
+	print ""
+	print ctype " {"
+	print cg["fields"] "};"
+
+	# XXX: This should also check if it isn't out-of-range for any reason,
+	# but our usage of sprintf() stands in the way a bit.
+	CodegenSerialize[name] = "\tstr_pack_i8(w, %s);\n"
+	CodegenDeserialize[name] = \
+		"\t{\n" \
+		"\t\tint8_t v = 0;\n" \
+		"\t\tif (!msg_unpacker_i8(r, &v) || !v)\n" \
+		"\t\t\treturn false;\n" \
+		"\t\t%s = v;\n" \
+		"\t}\n"
+
+	CodegenCType[name] = ctype
+	for (i in cg)
+		delete cg[i]
+}
+
+function codegen_struct_tag(d, cg,    f) {
+	f = "self->" d["name"]
+	append(cg, "fields", "\t" CodegenCType[d["type"]] " " d["name"] ";\n")
+	append(cg, "dispose", sprintf(CodegenDispose[d["type"]], f))
+	append(cg, "serialize", sprintf(CodegenSerialize[d["type"]], f))
+	# Do not deserialize here, that would be out of order.
+}
+
+function codegen_struct_field(d, cg,    f, dispose, serialize, deserialize) {
+	f = "self->" d["name"]
+	dispose = CodegenDispose[d["type"]]
+	serialize = CodegenSerialize[d["type"]]
+	deserialize = CodegenDeserialize[d["type"]]
+	if (!d["isarray"]) {
+		append(cg, "fields", "\t" CodegenCType[d["type"]] " " d["name"] ";\n")
+		append(cg, "dispose", sprintf(dispose, f))
+		append(cg, "serialize", sprintf(serialize, f))
+		append(cg, "deserialize", sprintf(deserialize, f))
+		return
+	}
+
+	append(cg, "fields",
+		"\t" CodegenCType["u32"] " " d["name"] "_len;\n" \
+		"\t" CodegenCType[d["type"]] " *" d["name"] ";\n")
+
+	if (dispose)
+		append(cg, "dispose", "\tif (" f ")\n" \
+			"\t\tfor (size_t i = 0; i < " f "_len; i++)\n" \
+			indent(indent(sprintf(dispose, f "[i]"))))
+	append(cg, "dispose", "\tfree(" f ");\n")
+
+	append(cg, "serialize", sprintf(CodegenSerialize["u32"], f "_len"))
+	if (d["type"] == "u8" || d["type"] == "i8") {
+		append(cg, "serialize",
+			"\tstr_append_data(w, " f ", " f "_len);\n")
+	} else if (serialize) {
+		append(cg, "serialize",
+			"\tfor (size_t i = 0; i < " f "_len; i++)\n" \
+			indent(sprintf(serialize, f "[i]")))
+	}
+
+	append(cg, "deserialize", sprintf(CodegenDeserialize["u32"], f "_len") \
+		"\tif (!(" f " = calloc(" f "_len + 1, sizeof *" f ")))\n" \
+		"\t\treturn false;\n")
+	if (d["type"] == "u8" || d["type"] == "i8") {
+		append(cg, "deserialize",
+			"\tif (msg_unpacker_get_available(r) < " f "_len)\n" \
+			"\t\treturn false;\n" \
+			"\tmemcpy(" f ", r->data + r->offset, " f "_len);\n" \
+			"\tr->offset += " f "_len;\n")
+	} else if (deserialize) {
+		append(cg, "deserialize",
+			"\tfor (size_t i = 0; i < " f "_len; i++)\n" \
+			indent(sprintf(deserialize, f "[i]")))
+	}
+}
+
+function codegen_struct(name, cg,    ctype, funcname) {
+	ctype = "struct " PrefixLower cameltosnake(name)
+	print ""
+	print ctype " {"
+	print cg["fields"] "};"
+
+	if (cg["dispose"]) {
+		funcname = PrefixLower cameltosnake(name) "_free"
+		print ""
+		print "static void\n" funcname "(" ctype " *self) {"
+		print cg["dispose"] "}"
+
+		CodegenDispose[name] = "\t" funcname "(&%s);\n"
+	}
+	if (cg["serialize"]) {
+		funcname = PrefixLower cameltosnake(name) "_serialize"
+		print ""
+		print "static bool\n" \
+			  funcname "(\n\t\t" ctype " *self, struct str *w) {"
+		print cg["serialize"] "\treturn true;"
+		print "}"
+
+		CodegenSerialize[name] = "\tif (!" funcname "(&%s, w))\n" \
+			"\t\treturn false;\n"
+	}
+	if (cg["deserialize"]) {
+		funcname = PrefixLower cameltosnake(name) "_deserialize"
+		print ""
+		print "static bool\n" \
+			  funcname "(\n\t\t" ctype " *self, struct msg_unpacker *r) {"
+		print cg["deserialize"] "\treturn true;"
+		print "}"
+
+		CodegenDeserialize[name] = "\tif (!" funcname "(&%s, r))\n" \
+			"\t\treturn false;\n"
+	}
+
+	CodegenCType[name] = ctype
+	for (i in cg)
+		delete cg[i]
+}
+
+function codegen_union_tag(d, cg) {
+	cg["tagtype"] = d["type"]
+	cg["tagname"] = d["name"]
+	append(cg, "fields", "\t" CodegenCType[d["type"]] " " d["name"] ";\n")
+}
+
+function codegen_union_struct( \
+		name, casename, cg, scg,     structname, fieldname, fullcasename) {
+	# Don't generate obviously useless structs.
+	fullcasename = toupper(cameltosnake(cg["tagtype"])) "_" casename
+	if (!scg["dispose"] && !scg["deserialize"]) {
+		append(cg, "structless", "\tcase " PrefixUpper fullcasename ":\n")
+		for (i in scg)
+			delete scg[i]
+		return
+	}
+
+	# And thus not all generated structs are present in Types.
+	structname = name "_" casename
+	fieldname = tolower(casename)
+	codegen_struct(structname, scg)
+
+	append(cg, "fields", "\t" CodegenCType[structname] " " fieldname ";\n")
+	if (CodegenDispose[structname])
+		append(cg, "dispose", "\tcase " PrefixUpper fullcasename ":\n" \
+			indent(sprintf(CodegenDispose[structname], "self->" fieldname)) \
+			"\t\tbreak;\n")
+
+	# With no de/serialization code, this will simply recognize the tag.
+	append(cg, "serialize", "\tcase " PrefixUpper fullcasename ":\n" \
+		indent(sprintf(CodegenSerialize[structname], "self->" fieldname)) \
+		"\t\tbreak;\n")
+	append(cg, "deserialize", "\tcase " PrefixUpper fullcasename ":\n" \
+		indent(sprintf(CodegenDeserialize[structname], "self->" fieldname)) \
+		"\t\tbreak;\n")
+}
+
+function codegen_union(name, cg,    f, ctype, funcname) {
+	ctype = "union " PrefixLower cameltosnake(name)
+	print ""
+	print ctype " {"
+	print cg["fields"] "};"
+
+	f = "self->" cg["tagname"]
+	if (cg["dispose"]) {
+		funcname = PrefixLower cameltosnake(name) "_free"
+		print ""
+		print "static void\n" funcname "(" ctype " *self) {"
+		print "\tswitch (" f ") {"
+		if (cg["structless"])
+			print cg["structless"] \
+				indent(sprintf(CodegenDispose[cg["tagtype"]], f)) "\t\tbreak;"
+		print cg["dispose"] "\tdefault:"
+		print "\t\tbreak;"
+		print "\t}"
+		print "}"
+
+		CodegenDispose[name] = "\t" funcname "(&%s);\n"
+	}
+	if (cg["serialize"]) {
+		funcname = PrefixLower cameltosnake(name) "_serialize"
+		print ""
+		print "static bool\n" \
+			  funcname "(\n\t\t" ctype " *self, struct str *w) {"
+		print "\tswitch (" f ") {"
+		if (cg["structless"])
+			print cg["structless"] \
+				indent(sprintf(CodegenSerialize[cg["tagtype"]], f)) "\t\tbreak;"
+		print cg["serialize"] "\tdefault:"
+		print "\t\treturn false;"
+		print "\t}"
+		print "\treturn true;"
+		print "}"
+
+		CodegenSerialize[name] = "\tif (!" funcname "(&%s, w))\n" \
+			"\t\treturn false;\n"
+	}
+	if (cg["deserialize"]) {
+		funcname = PrefixLower cameltosnake(name) "_deserialize"
+		print ""
+		print "static bool\n" \
+			  funcname "(\n\t\t" ctype " *self, struct msg_unpacker *r) {"
+		print sprintf(CodegenDeserialize[cg["tagtype"]], f)
+		print "\tswitch (" f ") {"
+		if (cg["structless"])
+			print cg["structless"] "\t\tbreak;"
+		print cg["deserialize"] "\tdefault:"
+		print "\t\treturn false;"
+		print "\t}"
+		print "\treturn true;"
+		print "}"
+
+		CodegenDeserialize[name] = "\tif (!" funcname "(&%s, r))\n" \
+			"\t\treturn false;\n"
+	}
+
+	CodegenCType[name] = ctype
+	for (i in cg)
+		delete cg[i]
+}
--- a/xC-gen-proto-go.awk
+++ b/xC-gen-proto-go.awk
@@ -0,0 +1,519 @@
+# xC-gen-proto-go.awk: Go backend for xC-gen-proto.awk.
+#
+# Copyright (c) 2022, Přemysl Eric Janouch <p@janouch.name>
+# SPDX-License-Identifier: 0BSD
+#
+# This backend also enables proxying to other endpoints using JSON.
+
+function define_internal(name, gotype) {
+	Types[name] = "internal"
+	CodegenGoType[name] = gotype
+}
+
+function define_sint(size,    shortname, gotype) {
+	shortname = "i" size
+	gotype = "int" size
+	define_internal(shortname, gotype)
+
+	CodegenAppendJSON[shortname] = \
+		"\tb = strconv.AppendInt(b, int64(%s), 10)\n"
+	if (size == 8) {
+		CodegenSerialize[shortname] = "\tdata = append(data, uint8(%s))\n"
+		CodegenDeserialize[shortname] = \
+			"\tif len(data) >= 1 {\n" \
+			"\t\t%s, data = int8(data[0]), data[1:]\n" \
+			"\t} else {\n" \
+			"\t\treturn nil, false\n" \
+			"\t}\n"
+		return
+	}
+
+	CodegenSerialize[shortname] = \
+		"\tdata = binary.BigEndian.AppendUint" size "(data, uint" size "(%s))\n"
+	CodegenDeserialize[shortname] = \
+		"\tif len(data) >= " (size / 8) " {\n" \
+		"\t\t%s = " gotype "(binary.BigEndian.Uint" size "(data))\n" \
+		"\t\tdata = data[" (size / 8) ":]\n" \
+		"\t} else {\n" \
+		"\t\treturn nil, false\n" \
+		"\t}\n"
+}
+
+function define_uint(size,    shortname, gotype) {
+	# Both []byte and []uint8 luckily marshal as base64-encoded JSON strings,
+	# so there's no need to rename the type as an exception.
+	shortname = "u" size
+	gotype = "uint" size
+	define_internal(shortname, gotype)
+
+	CodegenAppendJSON[shortname] = \
+		"\tb = strconv.AppendUint(b, uint64(%s), 10)\n"
+	if (size == 8) {
+		CodegenSerialize[shortname] = "\tdata = append(data, %s)\n"
+		CodegenDeserialize[shortname] = \
+			"\tif len(data) >= 1 {\n" \
+			"\t\t%s, data = data[0], data[1:]\n" \
+			"\t} else {\n" \
+			"\t\treturn nil, false\n" \
+			"\t}\n"
+		return
+	}
+
+	CodegenSerialize[shortname] = \
+		"\tdata = binary.BigEndian.AppendUint" size "(data, %s)\n"
+	CodegenDeserialize[shortname] = \
+		"\tif len(data) >= " (size / 8) " {\n" \
+		"\t\t%s = binary.BigEndian.Uint" size "(data)\n" \
+		"\t\tdata = data[" (size / 8) ":]\n" \
+		"\t} else {\n" \
+		"\t\treturn nil, false\n" \
+		"\t}\n"
+}
+
+function codegen_begin() {
+	define_sint("8")
+	define_sint("16")
+	define_sint("32")
+	define_sint("64")
+	define_uint("8")
+	define_uint("16")
+	define_uint("32")
+	define_uint("64")
+
+	define_internal("bool", "bool")
+	CodegenAppendJSON["bool"] = \
+		"\tb = strconv.AppendBool(b, %s)\n"
+	CodegenSerialize["bool"] = \
+		"\tif %s {\n" \
+		"\t\tdata = append(data, 1)\n" \
+		"\t} else {\n" \
+		"\t\tdata = append(data, 0)\n" \
+		"\t}\n"
+	CodegenDeserialize["bool"] = \
+		"\tif data, ok = protoConsumeBoolFrom(data, &%s); !ok {\n" \
+		"\t\treturn nil, ok\n" \
+		"\t}\n"
+
+	define_internal("string", "string")
+	CodegenSerialize["string"] = \
+		"\tif data, ok = protoAppendStringTo(data, %s); !ok {\n" \
+		"\t\treturn nil, ok\n" \
+		"\t}\n"
+	CodegenDeserialize["string"] = \
+		"\tif data, ok = protoConsumeStringFrom(data, &%s); !ok {\n" \
+		"\t\treturn nil, ok\n" \
+		"\t}\n"
+
+	print "package main"
+	print ""
+	print "import ("
+	print "\t`encoding/base64`"
+	print "\t`encoding/binary`"
+	print "\t`encoding/json`"
+	print "\t`errors`"
+	print "\t`math`"
+	print "\t`strconv`"
+	print "\t`unicode/utf8`"
+	print ")"
+	print ""
+
+	print "// protoConsumeBoolFrom tries to deserialize a boolean value"
+	print "// from the beginning of a byte stream. When successful,"
+	print "// it returns a subslice with any data that might follow."
+	print "func protoConsumeBoolFrom(data []byte, b *bool) ([]byte, bool) {"
+	print "\tif len(data) < 1 {"
+	print "\t\treturn nil, false"
+	print "\t}"
+	print "\tif data[0] != 0 {"
+	print "\t\t*b = true"
+	print "\t} else {"
+	print "\t\t*b = false"
+	print "\t}"
+	print "\treturn data[1:], true"
+	print "}"
+	print ""
+
+	print "// protoAppendStringTo tries to serialize a string value,"
+	print "// appending it to the end of a byte stream."
+	print "func protoAppendStringTo(data []byte, s string) ([]byte, bool) {"
+	print "\tif len(s) > math.MaxUint32 {"
+	print "\t\treturn nil, false"
+	print "\t}"
+	print "\tdata = binary.BigEndian.AppendUint32(data, uint32(len(s)))"
+	print "\treturn append(data, s...), true"
+	print "}"
+	print ""
+
+	print "// protoConsumeStringFrom tries to deserialize a string value"
+	print "// from the beginning of a byte stream. When successful,"
+	print "// it returns a subslice with any data that might follow."
+	print "func protoConsumeStringFrom(data []byte, s *string) ([]byte, bool) {"
+	print "\tif len(data) < 4 {"
+	print "\t\treturn nil, false"
+	print "\t}"
+	print "\tlength := binary.BigEndian.Uint32(data)"
+	print "\tif data = data[4:]; uint64(len(data)) < uint64(length) {"
+	print "\t\treturn nil, false"
+	print "\t}"
+	print "\t*s = string(data[:length])"
+	print "\tif !utf8.ValidString(*s) {"
+	print "\t\treturn nil, false"
+	print "\t}"
+	print "\treturn data[length:], true"
+	print "}"
+	print ""
+
+	print "// protoUnmarshalEnumJSON converts a JSON fragment to an integer,"
+	print "// ensuring that it's within the expected range of enum values."
+	print "func protoUnmarshalEnumJSON(data []byte) (int64, error) {"
+	print "\tvar n int64"
+	print "\tif err := json.Unmarshal(data, &n); err != nil {"
+	print "\t\treturn 0, err"
+	print "\t} else if n > math.MaxInt8 || n < math.MinInt8 {"
+	print "\t\treturn 0, errors.New(`integer out of range`)"
+	print "\t} else {"
+	print "\t\treturn n, nil"
+	print "\t}"
+	print "}"
+	print ""
+}
+
+function codegen_constant(name, value) {
+	print "const " PrefixCamel snaketocamel(name) " = " value
+	print ""
+}
+
+function codegen_enum_value(name, subname, value, cg,    goname) {
+	goname = PrefixCamel name snaketocamel(subname)
+	append(cg, "fields",
+		"\t" goname " = " value "\n")
+	append(cg, "stringer",
+		"\tcase " goname ":\n" \
+		"\t\treturn `" snaketocamel(subname) "`\n")
+	append(cg, "marshal",
+		goname ",\n")
+	append(cg, "unmarshal",
+		"\tcase `" snaketocamel(subname) "`:\n" \
+		"\t\t*v = " goname "\n")
+}
+
+function codegen_enum(name, cg,    gotype, fields) {
+	gotype = PrefixCamel name
+	print "type " gotype " int8"
+	print ""
+
+	print "const ("
+	print cg["fields"] ")"
+	print ""
+
+	print "func (v " gotype ") String() string {"
+	print "\tswitch v {"
+	print cg["stringer"] "\tdefault:"
+	print "\t\treturn strconv.Itoa(int(v))"
+	print "\t}"
+	print "}"
+	print ""
+
+	CodegenIsMarshaler[name] = 1
+	fields = cg["marshal"]
+	sub(/,\n$/, ":", fields)
+	gsub(/\n/, "\n\t", fields)
+	print "func (v " gotype ") MarshalJSON() ([]byte, error) {"
+	print "\tswitch v {"
+	print indent("case " fields)
+	print "\t\treturn []byte(`\"` + v.String() + `\"`), nil"
+	print "\t}"
+	print "\treturn json.Marshal(int(v))"
+	print "}"
+	print ""
+
+	print "func (v *" gotype ") UnmarshalJSON(data []byte) error {"
+	print "\tvar s string"
+	print "\tif json.Unmarshal(data, &s) == nil {"
+	print "\t\t// Handled below."
+	print "\t} else if n, err := protoUnmarshalEnumJSON(data); err != nil {"
+	print "\t\treturn err"
+	print "\t} else {"
+	print "\t\t*v = " gotype "(n)"
+	print "\t\treturn nil"
+	print "\t}"
+	print ""
+	print "\tswitch s {"
+	print cg["unmarshal"] "\tdefault:"
+	print "\t\treturn errors.New(`unrecognized value: ` + s)"
+	print "\t}"
+	print "\treturn nil"
+	print "}"
+	print ""
+
+	# XXX: This should also check if it isn't out-of-range for any reason,
+	# but our usage of sprintf() stands in the way a bit.
+	CodegenSerialize[name] = "\tdata = append(data, uint8(%s))\n"
+	CodegenDeserialize[name] = \
+		"\tif len(data) >= 1 {\n" \
+		"\t\t%s, data = " gotype "(data[0]), data[1:]\n" \
+		"\t} else {\n" \
+		"\t\treturn nil, false\n" \
+		"\t}\n"
+
+	CodegenGoType[name] = gotype
+	for (i in cg)
+		delete cg[i]
+}
+
+function codegen_marshal(type, f,    marshal) {
+	if (CodegenAppendJSON[type])
+		return sprintf(CodegenAppendJSON[type], f)
+
+	# Complex types are json.Marshalers, there's no need to json.Marshal(&f).
+	if (CodegenIsMarshaler[type])
+		marshal = f ".MarshalJSON()"
+	else
+		marshal = "json.Marshal(" f ")"
+
+	return \
+		"\tif j, err := " marshal "; err != nil {\n" \
+		"\t\treturn nil, err\n" \
+		"\t} else {\n" \
+		"\t\tb = append(b, j...)\n" \
+		"\t}\n"
+}
+
+function codegen_struct_field_marshal(d, cg,    camel, f, marshal) {
+	camel = snaketocamel(d["name"])
+	f = "s." camel
+	if (!d["isarray"]) {
+		append(cg, "marshal",
+			"\tb = append(b, `,\"" decapitalize(camel) "\":`...)\n" \
+			codegen_marshal(d["type"], f))
+		return
+	}
+
+	# Note that we do not produce `null` for nil slices, unlike encoding/json.
+	# And arrays never get deserialized as such.
+	if (d["type"] == "u8") {
+		append(cg, "marshal",
+			"\tb = append(b, `,\"" decapitalize(camel) "\":\"`...)\n" \
+			"\tb = append(b, base64.StdEncoding.EncodeToString(" f ")...)\n" \
+			"\tb = append(b, '\"')\n")
+		return
+	}
+
+	append(cg, "marshal",
+		"\tb = append(b, `,\"" decapitalize(camel) "\":[`...)\n" \
+		"\tfor i := 0; i < len(" f "); i++ {\n" \
+		"\t\tif i > 0 {\n" \
+		"\t\t\tb = append(b, ',')\n" \
+		"\t\t}\n" \
+		indent(codegen_marshal(d["type"], f "[i]")) \
+		"\t}\n" \
+		"\tb = append(b, ']')\n")
+}
+
+function codegen_struct_field(d, cg,    camel, f, serialize, deserialize) {
+	codegen_struct_field_marshal(d, cg)
+
+	camel = snaketocamel(d["name"])
+	f = "s." camel
+	serialize = CodegenSerialize[d["type"]]
+	deserialize = CodegenDeserialize[d["type"]]
+	if (!d["isarray"]) {
+		append(cg, "fields", "\t" camel " " CodegenGoType[d["type"]] \
+			" `json:\"" decapitalize(camel) "\"`\n")
+		append(cg, "serialize", sprintf(serialize, f))
+		append(cg, "deserialize", sprintf(deserialize, f))
+		return
+	}
+
+	append(cg, "fields", "\t" camel " []" CodegenGoType[d["type"]] \
+		" `json:\"" decapitalize(camel) "\"`\n")
+
+	# XXX: This should also check if it isn't out-of-range for any reason.
+	append(cg, "serialize",
+		sprintf(CodegenSerialize["u32"], "uint32(len(" f "))"))
+	if (d["type"] == "u8") {
+		append(cg, "serialize",
+			"\tdata = append(data, " f "...)\n")
+	} else {
+		append(cg, "serialize",
+			"\tfor i := 0; i < len(" f "); i++ {\n" \
+			indent(sprintf(serialize, f "[i]")) \
+			"\t}\n")
+	}
+
+	append(cg, "deserialize",
+		"\t{\n" \
+		"\t\tvar length uint32\n" \
+		indent(sprintf(CodegenDeserialize["u32"], "length")))
+	if (d["type"] == "u8") {
+		append(cg, "deserialize",
+			"\t\tif uint64(len(data)) < uint64(length) {\n" \
+			"\t\t\treturn nil, false\n" \
+			"\t\t}\n" \
+			"\t\t" f ", data = data[:length], data[length:]\n" \
+			"\t}\n")
+	} else {
+		append(cg, "deserialize",
+			"\t\t" f " = make([]" CodegenGoType[d["type"]] ", length)\n" \
+			"\t}\n" \
+			"\tfor i := 0; i < len(" f "); i++ {\n" \
+			indent(sprintf(deserialize, f "[i]")) \
+			"\t}\n")
+	}
+}
+
+function codegen_struct_tag(d, cg,    camel, f) {
+	codegen_struct_field_marshal(d, cg)
+
+	camel = snaketocamel(d["name"])
+	f = "s." camel
+	append(cg, "fields", "\t" camel " " CodegenGoType[d["type"]] \
+		" `json:\"" decapitalize(camel) "\"`\n")
+	append(cg, "serialize", sprintf(CodegenSerialize[d["type"]], f))
+	# Do not deserialize here, that is already done by the containing union.
+}
+
+function codegen_struct(name, cg,    gotype) {
+	gotype = PrefixCamel name
+	print "type " gotype " struct {\n" cg["fields"] "}\n"
+
+	if (cg["marshal"]) {
+		CodegenIsMarshaler[name] = 1
+		print "func (s *" gotype ") MarshalJSON() ([]byte, error) {"
+		print "\tb := []byte{}"
+		print cg["marshal"] "\tb[0] = '{'"
+		print "\treturn append(b, '}'), nil"
+		print "}"
+		print ""
+	}
+
+	if (cg["serialize"]) {
+		print "func (s *" gotype ") AppendTo(data []byte) ([]byte, bool) {"
+		print "\tok := true"
+		print cg["serialize"] "\treturn data, ok"
+		print "}"
+		print ""
+
+		CodegenSerialize[name] = \
+			"\tif data, ok = %s.AppendTo(data); !ok {\n" \
+			"\t\treturn nil, ok\n" \
+			"\t}\n"
+	}
+	if (cg["deserialize"]) {
+		print "func (s *" gotype ") ConsumeFrom(data []byte) ([]byte, bool) {"
+		print "\tok := true"
+		print cg["deserialize"] "\treturn data, ok"
+		print "}"
+		print ""
+
+		CodegenDeserialize[name] = \
+			"\tif data, ok = %s.ConsumeFrom(data); !ok {\n" \
+			"\t\treturn nil, ok\n" \
+			"\t}\n"
+	}
+
+	CodegenGoType[name] = gotype
+	for (i in cg)
+		delete cg[i]
+}
+
+function codegen_union_tag(d, cg) {
+	cg["tagtype"] = d["type"]
+	cg["tagname"] = d["name"]
+	# The tag is implied from the type of struct stored in the interface.
+}
+
+function codegen_union_struct(name, casename, cg, scg,     structname, init) {
+	# And thus not all generated structs are present in Types.
+	structname = name snaketocamel(casename)
+	codegen_struct(structname, scg)
+
+	init = CodegenGoType[structname] "{" snaketocamel(cg["tagname"]) \
+		": " decapitalize(snaketocamel(cg["tagname"])) "}"
+	append(cg, "unmarshal",
+		"\tcase " CodegenGoType[cg["tagtype"]] snaketocamel(casename) ":\n" \
+		"\t\ts := " init "\n" \
+		"\t\terr = json.Unmarshal(data, &s)\n" \
+		"\t\tu.Interface = &s\n")
+	append(cg, "serialize",
+		"\tcase *" CodegenGoType[structname] ":\n" \
+		indent(sprintf(CodegenSerialize[structname], "union")))
+	append(cg, "deserialize",
+		"\tcase " CodegenGoType[cg["tagtype"]] snaketocamel(casename) ":\n" \
+		"\t\ts := " init "\n" \
+		indent(sprintf(CodegenDeserialize[structname], "s")) \
+		"\t\tu.Interface = &s\n")
+}
+
+function codegen_union(name, cg,    gotype, tagfield, tagvar) {
+	gotype = PrefixCamel name
+	print "type " gotype " struct {"
+	print "\tInterface any"
+	print "}"
+	print ""
+
+	# This cannot be a pointer method, it wouldn't work recursively.
+	CodegenIsMarshaler[name] = 1
+	print "func (u " gotype ") MarshalJSON() ([]byte, error) {"
+	print "\treturn u.Interface.(json.Marshaler).MarshalJSON()"
+	print "}"
+	print ""
+
+	tagfield = snaketocamel(cg["tagname"])
+	tagvar = decapitalize(tagfield)
+	print "func (u *" gotype ") UnmarshalJSON(data []byte) (err error) {"
+	print "\tvar t struct {"
+	print "\t\t" tagfield " " CodegenGoType[cg["tagtype"]] \
+		" `json:\"" tagvar "\"`"
+	print "\t}"
+	print "\tif err := json.Unmarshal(data, &t); err != nil {"
+	print "\t\treturn err"
+	print "\t}"
+	print ""
+	print "\tswitch " tagvar " := t." tagfield "; " tagvar " {"
+	print cg["unmarshal"] "\tdefault:"
+	print "\t\terr = errors.New(`unsupported value: ` + " tagvar ".String())"
+	print "\t}"
+	print "\treturn err"
+	print "}"
+	print ""
+
+	# XXX: Consider changing the interface into an AppendTo/ConsumeFrom one,
+	# that would eliminate these type case switches entirely.
+	# On the other hand, it would make it possible to send unsuitable structs.
+	print "func (u *" gotype ") AppendTo(data []byte) ([]byte, bool) {"
+	print "\tok := true"
+	print "\tswitch union := u.Interface.(type) {"
+	print cg["serialize"] "\tdefault:"
+	print "\t\treturn nil, false"
+	print "\t}"
+	print "\treturn data, ok"
+	print "}"
+	print ""
+
+	CodegenSerialize[name] = \
+		"\tif data, ok = %s.AppendTo(data); !ok {\n" \
+		"\t\treturn nil, ok\n" \
+		"\t}\n"
+
+	print "func (u *" gotype ") ConsumeFrom(data []byte) ([]byte, bool) {"
+	print "\tok := true"
+	print "\tvar " tagvar " " CodegenGoType[cg["tagtype"]]
+	print sprintf(CodegenDeserialize[cg["tagtype"]], tagvar)
+	print "\tswitch " tagvar " {"
+	print cg["deserialize"] "\tdefault:"
+	print "\t\treturn nil, false"
+	print "\t}"
+	print "\treturn data, ok"
+	print "}"
+	print ""
+
+	CodegenDeserialize[name] = \
+		"\tif data, ok = %s.ConsumeFrom(data); !ok {\n" \
+		"\t\treturn nil, ok\n" \
+		"\t}\n"
+
+	CodegenGoType[name] = gotype
+	for (i in cg)
+		delete cg[i]
+}
--- a/xC-gen-proto-js.awk
+++ b/xC-gen-proto-js.awk
@@ -0,0 +1,223 @@
+# xC-gen-proto-js.awk: Javascript backend for xC-gen-proto.awk.
+#
+# Copyright (c) 2022, Přemysl Eric Janouch <p@janouch.name>
+# SPDX-License-Identifier: 0BSD
+#
+# This backend is currently for decoding the binary format only.
+# (JSON is way too expensive to process and transfer.)
+#
+# Import the resulting script as a Javascript module.
+
+function define_internal(name) {
+	Types[name] = "internal"
+}
+
+function define_sint(size,    shortname) {
+	shortname = "i" size
+	define_internal(shortname)
+	CodegenDeserialize[shortname] = "\t%s = r." shortname "()\n"
+
+	print ""
+	print "\t" shortname "() {"
+	if (size == "64") {
+		# XXX: 2^53 - 1 must be enough for anyone.  BigInts are a PITA.
+		print "\t\tconst " shortname \
+			" = Number(this.getBigInt" size "(this.offset))"
+	} else {
+		print "\t\tconst " shortname " = this.getInt" size "(this.offset)"
+	}
+	print "\t\tthis.offset += " (size / 8)
+	print "\t\treturn " shortname
+	print "\t}"
+}
+
+function define_uint(size,    shortname) {
+	shortname = "u" size
+	define_internal(shortname)
+	CodegenDeserialize[shortname] = "\t%s = r." shortname "()\n"
+
+	print ""
+	print "\t" shortname "() {"
+	if (size == "64") {
+		# XXX: 2^53 - 1 must be enough for anyone.  BigInts are a PITA.
+		print "\t\tconst " shortname \
+			" = Number(this.getBigUint" size "(this.offset))"
+	} else {
+		print "\t\tconst " shortname " = this.getUint" size "(this.offset)"
+	}
+	print "\t\tthis.offset += " (size / 8)
+	print "\t\treturn " shortname
+	print "\t}"
+}
+
+function codegen_begin() {
+	print "export class Reader extends DataView {"
+	print "\tconstructor() {"
+	print "\t\tsuper(...arguments)"
+	print "\t\tthis.offset = 0"
+	print "\t\tthis.decoder = new TextDecoder('utf-8', {fatal: true})"
+	print "\t}"
+	print ""
+	print "\tget empty() {"
+	print "\t\treturn this.byteLength <= this.offset"
+	print "\t}"
+	print ""
+	print "\trequire(len) {"
+	print "\t\tif (this.byteLength - this.offset < len)"
+	print "\t\t\tthrow `Premature end of data`"
+	print "\t\treturn this.byteOffset + this.offset"
+	print "\t}"
+
+	define_internal("string")
+	CodegenDeserialize["string"] = "\t%s = r.string()\n"
+
+	print ""
+	print "\tstring() {"
+	print "\t\tconst len = this.getUint32(this.offset)"
+	print "\t\tthis.offset += 4"
+	print "\t\tconst array = new Uint8Array("
+	print "\t\t\tthis.buffer, this.require(len), len)"
+	print "\t\tthis.offset += len"
+	print "\t\treturn this.decoder.decode(array)"
+	print "\t}"
+
+	define_internal("bool")
+	CodegenDeserialize["bool"] = "\t%s = r.bool()\n"
+
+	print ""
+	print "\tbool() {"
+	print "\t\tconst u8 = this.getUint8(this.offset)"
+	print "\t\tthis.offset += 1"
+	print "\t\treturn u8 != 0"
+	print "\t}"
+
+	define_sint("8")
+	define_sint("16")
+	define_sint("32")
+	define_sint("64")
+	define_uint("8")
+	define_uint("16")
+	define_uint("32")
+	define_uint("64")
+
+	print "}"
+}
+
+function codegen_constant(name, value) {
+	print ""
+	print "export const " decapitalize(snaketocamel(name)) " = " value
+}
+
+function codegen_enum_value(name, subname, value, cg) {
+	append(cg, "fields", "\t" snaketocamel(subname) ": " value ",\n")
+}
+
+function codegen_enum(name, cg) {
+	print ""
+	print "export const " name " = Object.freeze({"
+	print cg["fields"] "})"
+
+	CodegenDeserialize[name] = "\t%s = r.i8()\n"
+	for (i in cg)
+		delete cg[i]
+}
+
+function codegen_struct_field(d, cg,    camel, f, deserialize) {
+	camel = decapitalize(snaketocamel(d["name"]))
+	f = "s." camel
+	append(cg, "fields", "\t" camel "\n")
+
+	deserialize = CodegenDeserialize[d["type"]]
+	if (!d["isarray"]) {
+		append(cg, "deserialize", sprintf(deserialize, f))
+		return
+	}
+
+	append(cg, "deserialize",
+		"\t{\n" \
+		indent(sprintf(CodegenDeserialize["u32"], "const len")))
+	if (d["type"] == "u8") {
+		append(cg, "deserialize",
+			"\t\t" f " = new Uint8Array(\n" \
+			"\t\t\tr.buffer, r.require(len), len)\n" \
+			"\t\tr.offset += len\n" \
+			"\t}\n")
+		return
+	}
+	if (d["type"] == "i8") {
+		append(cg, "deserialize",
+			"\t\t" f " = new Int8Array(\n" \
+			"\t\t\tr.buffer, r.require(len), len)\n" \
+			"\t\tr.offset += len\n" \
+			"\t}\n")
+		return
+	}
+
+	append(cg, "deserialize",
+		"\t\t" f " = new Array(len)\n" \
+		"\t}\n" \
+		"\tfor (let i = 0; i < " f ".length; i++)\n" \
+		indent(sprintf(deserialize, f "[i]")))
+}
+
+function codegen_struct_tag(d, cg) {
+	append(cg, "fields", "\t" decapitalize(snaketocamel(d["name"])) "\n")
+	# Do not deserialize here, that is already done by the containing union.
+}
+
+function codegen_struct(name, cg) {
+	print ""
+	print "export class " name " {"
+	print cg["fields"] cg["methods"]
+	print "\tstatic deserialize(r) {"
+	print "\t\tconst s = new " name "()"
+	print indent(cg["deserialize"]) "\t\treturn s"
+	print "\t}"
+	print "}"
+
+	CodegenDeserialize[name] = "\t%s = " name ".deserialize(r)\n"
+	for (i in cg)
+		delete cg[i]
+}
+
+function codegen_union_tag(d, cg) {
+	cg["tagtype"] = d["type"]
+	cg["tagname"] = d["name"]
+}
+
+function codegen_union_struct(name, casename, cg, scg,     structname) {
+	append(scg, "methods",
+		"\n" \
+		"\tconstructor() {\n" \
+		"\t\tthis." decapitalize(snaketocamel(cg["tagname"])) \
+			" = " cg["tagtype"] "." snaketocamel(casename) "\n" \
+		"\t}\n")
+
+	# And thus not all generated structs are present in Types.
+	structname = name snaketocamel(casename)
+	codegen_struct(structname, scg)
+
+	append(cg, "deserialize",
+		"\tcase " cg["tagtype"] "." snaketocamel(casename) ":\n" \
+		"\t{\n" \
+		indent(sprintf(CodegenDeserialize[structname], "const s")) \
+		"\t\treturn s\n" \
+		"\t}\n")
+}
+
+function codegen_union(name, cg,    tagvar) {
+	tagvar = decapitalize(snaketocamel(cg["tagname"]))
+
+	print ""
+	print "export function deserialize" name "(r) {"
+	print sprintf(CodegenDeserialize[cg["tagtype"]], "const " tagvar) \
+		"\tswitch (" tagvar ") {"
+	print cg["deserialize"] "\tdefault:"
+	print "\t\tthrow `Unknown " cg["tagtype"] " (${tagvar})`"
+	print "\t}"
+	print "}"
+
+	CodegenDeserialize[name] = "\t%s = deserialize" name "(r)\n"
+	for (i in cg)
+		delete cg[i]
+}
--- a/xC-gen-proto.awk
+++ b/xC-gen-proto.awk
@@ -0,0 +1,305 @@
+# xC-gen-proto.awk: an XDR-derived code generator for network protocols.
+#
+# Copyright (c) 2022, Přemysl Eric Janouch <p@janouch.name>
+# SPDX-License-Identifier: 0BSD
+#
+# You may read RFC 4506 for context, however it is only a source of inspiration.
+# Grammar is easy to deduce from the parser.
+#
+# Native types: bool, u{8,16,32,64}, i{8,16,32,64}, string
+#
+# Don't define any new types, unless you hate yourself, then it's okay to do so.
+# Backends tend to be a pain in the arse, for different reasons.
+#
+# All numbers are encoded in big-endian byte order.
+# Booleans are one byte each.
+# Strings must be valid UTF-8, use u8<> to lift that restriction.
+# String and array lengths are encoded as u32.
+# Enumeration values automatically start at 1, and are encoded as i8.
+# Any struct or union field may be a variable-length array.
+#
+# Message framing is done externally, but also happens to prefix u32 lengths,
+# unless this role is already filled by, e.g., WebSocket.
+#
+# Usage: env LC_ALL=C awk -f xC-gen-proto.awk -f xC-gen-proto-{c,go,js}.awk \
+#  xC-proto > xC-proto.{c,go,js} | {clang-format,gofmt,...}
+
+# --- Utilities ----------------------------------------------------------------
+
+function cameltosnake(s) {
+	while (match(s, /[[:lower:]][[:upper:]]/)) {
+		s = substr(s, 1, RSTART) "_" \
+			tolower(substr(s, RSTART + 1, RLENGTH - 1)) \
+			substr(s, RSTART + RLENGTH)
+	}
+	return tolower(s)
+}
+
+function snaketocamel(s) {
+	s = toupper(substr(s, 1, 1)) tolower(substr(s, 2))
+	while (match(s, /_[[:alnum:]]/)) {
+		s = substr(s, 1, RSTART - 1) \
+			toupper(substr(s, RSTART + 1, RLENGTH - 1)) \
+			substr(s, RSTART + RLENGTH)
+	}
+	return s
+}
+
+function decapitalize(s) {
+	if (match(s, /[[:upper:]][[:lower:]]/)) {
+		return tolower(substr(s, 1, 1)) substr(s, 2)
+	}
+	return s
+}
+
+function indent(s) {
+	if (!s)
+		return s
+
+	gsub(/\n/, "\n\t", s)
+	sub(/\t*$/, "", s)
+	return "\t" s
+}
+
+function append(a, key, value) {
+	a[key] = a[key] value
+}
+
+# --- Parsing ------------------------------------------------------------------
+
+function fatal(message) {
+	print "// " FILENAME ":" FNR ": fatal error: " message
+	print FILENAME ":" FNR ": fatal error: " message > "/dev/stderr"
+	exit 1
+}
+
+function skipcomment() {
+	do {
+		if (match($0, /[*][/]/)) {
+			$0 = substr($0, RSTART + RLENGTH)
+			return
+		}
+	} while (getline > 0)
+	fatal("unterminated block comment")
+}
+
+function nexttoken() {
+	do {
+		if (match($0, /^[[:space:]]+/)) {
+			$0 = substr($0, RLENGTH + 1)
+		} else if (match($0, /^[/][/].*/)) {
+			$0 = ""
+		} else if (match($0, /^[/][*]/)) {
+			$0 = substr($0, RLENGTH + 1)
+			skipcomment()
+		} else if (match($0, /^[[:alpha:]][[:alnum:]_]*/)) {
+			Token = substr($0, 1, RLENGTH)
+			$0 = substr($0, RLENGTH + 1)
+			return Token
+		} else if (match($0, /^(0[xX][0-9a-fA-F]+|[1-9][0-9]*)/)) {
+			Token = substr($0, 1, RLENGTH)
+			$0 = substr($0, RLENGTH + 1)
+			return Token
+		} else if (/./) {
+			Token = substr($0, 1, 1)
+			$0 = substr($0, 2)
+			return Token
+		}
+	} while (/./ || getline > 0)
+	Token = ""
+	return Token
+}
+
+function expect(v) {
+	if (!v)
+		fatal("broken expectations at `" Token "' before `" $0 "'")
+	return v
+}
+
+function accept(what) {
+	if (Token != what)
+		return 0
+	nexttoken()
+	return 1
+}
+
+function identifier(    v) {
+	if (Token !~ /^[[:alpha:]]/)
+		return 0
+	v = Token
+	nexttoken()
+	return v
+}
+
+function number(    v) {
+	if (Token !~ /^[0-9]/)
+		return 0
+	v = Token
+	nexttoken()
+	return v
+}
+
+function readnumber(    ident) {
+	ident = identifier()
+	if (!ident)
+		return expect(number())
+	if (!(ident in Consts))
+		fatal("unknown constant: " ident)
+	return Consts[ident]
+}
+
+function defconst(    ident, num) {
+	if (!accept("const"))
+		return 0
+
+	ident = expect(identifier())
+	expect(accept("="))
+	num = readnumber()
+	if (ident in Consts)
+		fatal("constant redefined: " ident)
+
+	Consts[ident] = num
+	codegen_constant(ident, num)
+	return 1
+}
+
+function readtype(    ident) {
+	ident = deftype()
+	if (ident)
+		return ident
+
+	ident = identifier()
+	if (!ident)
+		return 0
+
+	if (!(ident in Types))
+		fatal("unknown type: " ident)
+	return ident
+}
+
+function defenum(    name, ident, value, cg) {
+	delete cg[0]
+
+	name = expect(identifier())
+	expect(accept("{"))
+	while (!accept("}")) {
+		ident = expect(identifier())
+		value = value + 1
+		if (accept("="))
+			value = readnumber()
+		if (!value)
+			fatal("enumeration values cannot be zero")
+		if (value < -128 || value > 127)
+			fatal("enumeration value out of range")
+		expect(accept(","))
+		append(EnumValues, name, SUBSEP ident)
+		if (EnumValues[name, ident]++)
+			fatal("duplicate enum value: " ident)
+		codegen_enum_value(name, ident, value, cg)
+	}
+
+	Types[name] = "enum"
+	codegen_enum(name, cg)
+	return name
+}
+
+function readfield(out,    nonvoid) {
+	nonvoid = !accept("void")
+	if (nonvoid) {
+		out["type"] = expect(readtype())
+		out["name"] = expect(identifier())
+		# TODO: Consider supporting XDR's VLA length limits here.
+		# TODO: Consider supporting XDR's fixed-length syntax for string limits.
+		out["isarray"] = accept("<") && expect(accept(">"))
+	}
+	expect(accept(";"))
+	return nonvoid
+}
+
+function defstruct(    name, d, cg) {
+	delete d[0]
+	delete cg[0]
+
+	name = expect(identifier())
+	expect(accept("{"))
+	while (!accept("}")) {
+		if (readfield(d))
+			codegen_struct_field(d, cg)
+	}
+
+	Types[name] = "struct"
+	codegen_struct(name, cg)
+	return name
+}
+
+function defunion(    name, tag, tagtype, tagvalue, cg, scg, d, a, i, unseen) {
+	delete cg[0]
+	delete scg[0]
+	delete d[0]
+
+	name = expect(identifier())
+	expect(accept("switch"))
+	expect(accept("("))
+	tag["type"] = tagtype = expect(readtype())
+	tag["name"] = expect(identifier())
+	expect(accept(")"))
+
+	if (Types[tagtype] != "enum")
+		fatal("not an enum type: " tagtype)
+	codegen_union_tag(tag, cg)
+
+	split(EnumValues[tagtype], a, SUBSEP)
+	for (i in a)
+		unseen[a[i]]++
+
+	expect(accept("{"))
+	while (!accept("}")) {
+		if (accept("case")) {
+			if (tagvalue)
+				codegen_union_struct(name, tagvalue, cg, scg)
+
+			tagvalue = expect(identifier())
+			expect(accept(":"))
+			if (!unseen[tagvalue]--)
+				fatal("no such value or duplicate case: " tagtype "." tagvalue)
+			codegen_struct_tag(tag, scg)
+		} else if (tagvalue) {
+			if (readfield(d))
+				codegen_struct_field(d, scg)
+		} else {
+			fatal("union fields must fall under a case")
+		}
+	}
+	if (tagvalue)
+		codegen_union_struct(name, tagvalue, cg, scg)
+
+	# What remains non-zero in unseen[2..] is simply not recognized/allowed.
+	Types[name] = "union"
+	codegen_union(name, cg)
+	return name
+}
+
+function deftype() {
+	if (accept("enum"))
+		return defenum()
+	if (accept("struct"))
+		return defstruct()
+	if (accept("union"))
+		return defunion()
+	return 0
+}
+
+BEGIN {
+	PrefixLower = "relay_"
+	PrefixUpper = "RELAY_"
+	PrefixCamel = "Relay"
+
+	print "// Generated by xC-gen-proto.awk. DO NOT MODIFY."
+	codegen_begin()
+
+	nexttoken()
+	while (Token != "") {
+		expect(defconst() || deftype())
+		expect(accept(";"))
+	}
+}
--- a/206
+++ b/206
@@ -0,0 +1,206 @@
+// Backwards-compatible protocol version.
+const VERSION = 1;
+
+// From the frontend to the relay.
+struct CommandMessage {
+	// The command sequence number will be repeated in responses
+	// in the respective fields.
+	u32 command_seq;
+	union CommandData switch (enum Command {
+		HELLO,
+		ACTIVE,
+		BUFFER_ACTIVATE,
+		BUFFER_INPUT,
+		BUFFER_TOGGLE_UNIMPORTANT,
+		PING_RESPONSE,
+		PING,
+		BUFFER_COMPLETE,
+		BUFFER_LOG,
+	} command) {
+	// If the version check succeeds, the client will receive
+	// an initial stream of SERVER_UPDATE, BUFFER_UPDATE, BUFFER_STATS,
+	// BUFFER_LINE, and finally a BUFFER_ACTIVATE message.
+	case HELLO:
+		u32 version;
+	case ACTIVE:
+		void;
+	case BUFFER_ACTIVATE:
+		string buffer_name;
+	case BUFFER_INPUT:
+		string buffer_name;
+		string text;
+	// XXX: Perhaps this should rather be handled through a /buffer command.
+	case BUFFER_TOGGLE_UNIMPORTANT:
+		string buffer_name;
+	case PING_RESPONSE:
+		u32 event_seq;
+
+	// Only these commands may produce Event.RESPONSE, as below,
+	// but any command may produce an error.
+	case PING:
+		void;
+	case BUFFER_COMPLETE:
+		string buffer_name;
+		string text;
+		u32 position;
+	case BUFFER_LOG:
+		string buffer_name;
+	} data;
+};
+
+// From the relay to the frontend.
+struct EventMessage {
+	u32 event_seq;
+	union EventData switch (enum Event {
+		PING,
+		BUFFER_LINE,
+		BUFFER_UPDATE,
+		BUFFER_STATS,
+		BUFFER_RENAME,
+		BUFFER_REMOVE,
+		BUFFER_ACTIVATE,
+		BUFFER_CLEAR,
+		SERVER_UPDATE,
+		SERVER_RENAME,
+		SERVER_REMOVE,
+		ERROR,
+		RESPONSE,
+	} event) {
+	case PING:
+		void;
+
+	case BUFFER_LINE:
+		string buffer_name;
+		// Whether the line should also be displayed in the active buffer.
+		bool leak_to_active;
+		bool is_unimportant;
+		bool is_highlight;
+		enum Rendition {
+			BARE,
+			INDENT,
+			STATUS,
+			ERROR,
+			JOIN,
+			PART,
+			ACTION,
+		} rendition;
+		// Unix timestamp in milliseconds.
+		u64 when;
+		// Broken-up text, with in-band formatting.
+		union ItemData switch (enum Item {
+			TEXT,
+			RESET,
+			FG_COLOR,
+			BG_COLOR,
+			FLIP_BOLD,
+			FLIP_ITALIC,
+			FLIP_UNDERLINE,
+			FLIP_INVERSE,
+			FLIP_CROSSED_OUT,
+			FLIP_MONOSPACE,
+		} kind) {
+		case TEXT:
+			string text;
+		case RESET:
+			void;
+		case FG_COLOR:
+			i16 color;
+		case BG_COLOR:
+			i16 color;
+		case FLIP_BOLD:
+		case FLIP_ITALIC:
+		case FLIP_UNDERLINE:
+		case FLIP_INVERSE:
+		case FLIP_CROSSED_OUT:
+		case FLIP_MONOSPACE:
+			void;
+		} items<>;
+	case BUFFER_UPDATE:
+		string buffer_name;
+		bool hide_unimportant;
+		union BufferContext switch (enum BufferKind {
+			GLOBAL,
+			SERVER,
+			CHANNEL,
+			PRIVATE_MESSAGE,
+		} kind) {
+		case GLOBAL:
+			void;
+		case SERVER:
+			string server_name;
+		case CHANNEL:
+			string server_name;
+			ItemData topic<>;
+			// This includes parameters, separated by spaces.
+			string modes;
+		case PRIVATE_MESSAGE:
+			string server_name;
+		} context;
+	case BUFFER_STATS:
+		string buffer_name;
+		// These are cumulative, even for lines flushed out from buffers.
+		// Updates to these values aren't broadcasted, thus handle:
+		//  - BUFFER_LINE by bumping/setting them as appropriate,
+		//  - BUFFER_ACTIVATE by clearing them for the previous buffer
+		//    (this way, they can be used to mark unread messages).
+		u32 new_messages;
+		u32 new_unimportant_messages;
+		bool highlighted;
+	case BUFFER_RENAME:
+		string buffer_name;
+		string new;
+	case BUFFER_REMOVE:
+		string buffer_name;
+	case BUFFER_ACTIVATE:
+		string buffer_name;
+	case BUFFER_CLEAR:
+		string buffer_name;
+
+	case SERVER_UPDATE:
+		string server_name;
+		union ServerData switch (enum ServerState {
+			DISCONNECTED,
+			CONNECTING,
+			CONNECTED,
+			REGISTERED,
+			DISCONNECTING,
+		} state) {
+		case DISCONNECTED:
+		case CONNECTING:
+		case CONNECTED:
+			void;
+		case REGISTERED:
+			string user;
+			string user_modes;
+		// Theoretically, we could also send user information in this state,
+		// but we'd have to duplicate both fields.
+		case DISCONNECTING:
+			void;
+		} data;
+	case SERVER_RENAME:
+		// Buffers aren't sent updates for in this circumstance,
+		// as that wouldn't be sufficiently atomic anyway.
+		string server_name;
+		string new;
+	case SERVER_REMOVE:
+		string server_name;
+
+	// Restriction: command_seq strictly follows the sequence received
+	// by the relay, across both of these replies.
+	case ERROR:
+		u32 command_seq;
+		string error;
+	case RESPONSE:
+		u32 command_seq;
+		union ResponseData switch (Command command) {
+		case PING:
+			void;
+		case BUFFER_COMPLETE:
+			u32 start;
+			string completions<>;
+		case BUFFER_LOG:
+			// UTF-8, but not guaranteed.
+			u8 log<>;
+		} data;
+	} data;
+};
--- a/xC.adoc
+++ b/xC.adoc
@@ -1,8 +1,8 @@
 xC(1)
 =====
 :doctype: manpage
-:manmanual: uirc3 Manual
-:mansource: uirc3 {release-version}
+:manmanual: xK Manual
+:mansource: xK {release-version}

 Name
 ----
@@ -25,9 +25,9 @@ Options
 	other formatting marks to ANSI codes retrieved from the *terminfo*(5)
 	database:
 +
-```
+....
 printf '\x02bold\x02\n' | xC -f
-```
+....
 +
 This feature may be used to preview server MOTD files.

@@ -62,10 +62,10 @@ their respective function names:
 *M-a*: *goto-activity*::
 	Go to the first following buffer with unseen activity.
 *PageUp*: *display-backlog*::
-	Show the in-memory backlog for this buffer in the backlog helper,
+	Show the in-memory backlog for this buffer using *general.pager*,
 	which is almost certainly the *less*(1) program.
 *M-h*: *display-full-log*::
-	Show the log file for this buffer in the backlog helper.
+	Show the log file for this buffer using *general.pager*.
 *M-H*: *toggle-unimportant*::
 	Hide all join, part and quit messages, as well as all channel mode changes
 	that only relate to user channel modes.  Intended to reduce noise in
@@ -77,7 +77,8 @@ their respective function names:
 	The next key will be interpreted as a formatting mark to insert:
 	*c* for colours (optionally followed by numbers for the foreground
 	and background), *i* for italics, *b* for bold text, *u* for underlined,
-	*x* for struck-through, *v* for inverse text and *o* resets all formatting.
+	*s* for struck-through, *m* for monospace, *v* for inverse text,
+	and *o* resets all formatting.
 *C-l*: *redraw-screen*::
 	Should there be any issues with the display, this will clear the terminal
 	screen and redraw all information.
@@ -105,7 +106,7 @@ _~/.config/xC/xC.conf_::
 	as the */set* command, to make changes in it.

 _~/.local/share/xC/logs/_::
-	When enabled by *behaviour.logging*, log files are stored here.
+	When enabled by *general.logging*, log files are stored here.

 _~/.local/share/xC/plugins/_::
 _/usr/local/share/xC/plugins/_::
@@ -114,12 +115,11 @@ _/usr/share/xC/plugins/_::

 Bugs
 ----
-The editline (libedit) frontend is more of a proof of concept that mostly seems
-to work but exhibits bugs that are not our fault.
+The editline (libedit) frontend may exhibit some unexpected behaviour.

 Reporting bugs
 --------------
-Use https://git.janouch.name/p/uirc3 to report bugs, request features,
+Use https://git.janouch.name/p/xK to report bugs, request features,
 or submit pull requests.

 See also
--- a/xC.c
+++ b/xC.c
--- a/xC.png
+++ b/xC.png
--- a/xC.webp
+++ b/xC.webp
--- a/xD-gen-replies.awk
+++ b/xD-gen-replies.awk
@@ -0,0 +1,29 @@
+#!/usr/bin/awk -f
+BEGIN {
+	# The message catalog is a by-product
+	msg = "xD.msg"
+	print "$quote \"" > msg;
+	print "$set 1" > msg;
+}
+
+/^[0-9]+ *IRC_(ERR|RPL)_[A-Z]+ *".*"$/ {
+	match($0, /".*"/);
+	ids[$1] = $2;
+	texts[$2] = substr($0, RSTART, RLENGTH);
+	print $1 " " texts[$2] > msg
+}
+
+END {
+	printf("enum\n{")
+	for (i in ids) {
+		if (seen_first)
+			printf(",")
+		seen_first = 1
+		printf("\n\t%s = %s", ids[i], i)
+	}
+	print "\n};\n"
+	print "static const char *g_default_replies[] =\n{"
+	for (i in ids)
+		print "\t[" ids[i] "] = " texts[ids[i]] ","
+	print "};"
+}
--- a/xD-gen-replies.sh
+++ b/xD-gen-replies.sh
@@ -1,28 +0,0 @@
-#!/bin/sh
-LC_ALL=C exec awk '
-	BEGIN {
-		# The message catalog is a by-product
-		msg = "xD.msg"
-		print "$quote \"" > msg;
-		print "$set 1" > msg;
-	}
-	/^[0-9]+ *IRC_(ERR|RPL)_[A-Z]+ *".*"$/ {
-		match($0, /".*"/);
-		ids[$1] = $2;
-		texts[$2] = substr($0, RSTART, RLENGTH);
-		print $1 " " texts[$2] > msg
-	}
-	END {
-		printf("enum\n{")
-		for (i in ids) {
-			if (seen_first)
-				printf(",")
-			seen_first = 1
-			printf("\n\t%s = %s", ids[i], i)
-		}
-		print "\n};\n"
-		print "static const char *g_default_replies[] =\n{"
-		for (i in ids)
-			print "\t[" ids[i] "] = " texts[ids[i]] ","
-		print "};"
-	}'
--- a/xD.adoc
+++ b/xD.adoc
@@ -1,8 +1,8 @@
 xD(1)
 =====
 :doctype: manpage
-:manmanual: uirc3 Manual
-:mansource: uirc3 {release-version}
+:manmanual: xK Manual
+:mansource: xK {release-version}

 Name
 ----
@@ -49,5 +49,5 @@ _/etc/xdg/xD/xD.conf_::

 Reporting bugs
 --------------
-Use https://git.janouch.name/p/uirc3 to report bugs, request features,
+Use https://git.janouch.name/p/xK to report bugs, request features,
 or submit pull requests.
--- a/xD.c
+++ b/xD.c
@@ -1,7 +1,7 @@
 /*
 * xD.c: an IRC daemon
 *
- * Copyright (c) 2014 - 2020, Přemysl Eric Janouch <p@janouch.name>
+ * Copyright (c) 2014 - 2022, Přemysl Eric Janouch <p@janouch.name>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted.
@@ -22,7 +22,9 @@
 #define WANT_SYSLOG_LOGGING
 #include "common.c"
 #include "xD-replies.c"
+
 #include <nl_types.h>
+#include <sys/resource.h>

 enum { PIPE_READ, PIPE_WRITE };

@@ -851,8 +853,6 @@ client_send_str (struct client *c, const struct str *s)
 	str_append_data (&c->write_buffer, s->str,
 		MIN (s->len, IRC_MAX_MESSAGE_LENGTH));
 	str_append (&c->write_buffer, "\r\n");
-	// XXX: we might want to move this elsewhere, so that it doesn't get called
-	//   as often; it's going to cause a lot of syscalls with epoll.
 	client_update_poller (c, NULL);

 	// Technically we haven't sent it yet but that's a minor detail
@@ -2930,6 +2930,29 @@ irc_handle_links (const struct irc_message *msg, struct client *c)
 	irc_send_reply (c, IRC_RPL_ENDOFLINKS, mask);
 }

+static void
+irc_handle_wallops (const struct irc_message *msg, struct client *c)
+{
+	if (msg->params.len < 1)
+		RETURN_WITH_REPLY (c, IRC_ERR_NEEDMOREPARAMS, msg->command);
+	if (!(c->mode & IRC_USER_MODE_OPERATOR))
+		RETURN_WITH_REPLY (c, IRC_ERR_NOPRIVILEGES);
+
+	const char *message = msg->params.vector[0];
+
+	// Our interpretation: anonymize the sender,
+	// and target all users who want to receive these messages
+	struct str_map_iter iter = str_map_iter_make (&c->ctx->users);
+	struct client *target;
+	while ((target = str_map_iter_next (&iter)))
+	{
+		if (target != c && !(target->mode & IRC_USER_MODE_RX_WALLOPS))
+			continue;
+
+		client_send (target, ":%s WALLOPS :%s", c->ctx->server_name, message);
+	}
+}
+
 static void
 irc_handle_kill (const struct irc_message *msg, struct client *c)
 {
@@ -2992,6 +3015,7 @@ irc_register_handlers (struct server_context *ctx)
 		{ "ADMIN",    true,  irc_handle_admin,    0, 0 },
 		{ "STATS",    true,  irc_handle_stats,    0, 0 },
 		{ "LINKS",    true,  irc_handle_links,    0, 0 },
+		{ "WALLOPS",  true,  irc_handle_wallops,  0, 0 },

 		{ "MODE",     true,  irc_handle_mode,     0, 0 },
 		{ "PRIVMSG",  true,  irc_handle_privmsg,  0, 0 },
@@ -3069,6 +3093,7 @@ irc_try_read (struct client *c)
 		{
 			buf->str[buf->len += n_read] = '\0';
 			// TODO: discard characters above the 512 character limit
+			// FIXME: we should probably discard the data if closing_link
 			irc_process_buffer (buf, irc_process_message, c);
 			continue;
 		}
@@ -3110,6 +3135,7 @@ irc_try_read_tls (struct client *c)
 		case SSL_ERROR_NONE:
 			buf->str[buf->len += n_read] = '\0';
 			// TODO: discard characters above the 512 character limit
+			// FIXME: we should probably discard the data if closing_link
 			irc_process_buffer (buf, irc_process_message, c);
 			continue;
 		case SSL_ERROR_ZERO_RETURN:
@@ -3395,16 +3421,10 @@ irc_try_fetch_client (struct server_context *ctx, int listen_fd)
 		if (errno == EINTR)
 			return true;

-		if (errno == EBADF
-		 || errno == EINVAL
-		 || errno == ENOTSOCK
-		 || errno == EOPNOTSUPP)
+		if (accept_error_is_transient (errno))
+			print_warning ("%s: %s", "accept", strerror (errno));
+		else
 			print_fatal ("%s: %s", "accept", strerror (errno));
-
-		// OS kernels may return a wide range of unforeseeable errors.
-		// Assuming that they're either transient or caused by
-		// a connection that we've just extracted from the queue.
-		print_warning ("%s: %s", "accept", strerror (errno));
 		return true;
 	}

@@ -3788,10 +3808,9 @@ irc_lock_pid_file (struct server_context *ctx, struct error **e)
 }

 static int
-irc_listen (struct addrinfo *gai_iter)
+irc_listen (struct addrinfo *ai)
 {
-	int fd = socket (gai_iter->ai_family,
-		gai_iter->ai_socktype, gai_iter->ai_protocol);
+	int fd = socket (ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 	if (fd == -1)
 		return -1;
 	set_cloexec (fd);
@@ -3805,21 +3824,13 @@ irc_listen (struct addrinfo *gai_iter)
 #if defined SOL_IPV6 && defined IPV6_V6ONLY
 	// Make NULL always bind to both IPv4 and IPv6, irrespectively of the order
 	// of results; only INADDR6_ANY seems to be affected by this
-	if (gai_iter->ai_family == AF_INET6)
+	if (ai->ai_family == AF_INET6)
 		soft_assert (setsockopt (fd, SOL_IPV6, IPV6_V6ONLY,
 			&yes, sizeof yes) != -1);
 #endif

-	char host[NI_MAXHOST], port[NI_MAXSERV];
-	host[0] = port[0] = '\0';
-	int err = getnameinfo (gai_iter->ai_addr, gai_iter->ai_addrlen,
-		host, sizeof host, port, sizeof port,
-		NI_NUMERICHOST | NI_NUMERICSERV);
-	if (err)
-		print_debug ("%s: %s", "getnameinfo", gai_strerror (err));
-
-	char *address = format_host_port_pair (host, port);
-	if (bind (fd, gai_iter->ai_addr, gai_iter->ai_addrlen))
+	char *address = gai_reconstruct_address (ai);
+	if (bind (fd, ai->ai_addr, ai->ai_addrlen))
 		print_error ("bind to %s failed: %s", address, strerror (errno));
 	else if (listen (fd, 16 /* arbitrary number */))
 		print_error ("listen on %s failed: %s", address, strerror (errno));
@@ -3839,12 +3850,12 @@ static void
 irc_listen_resolve (struct server_context *ctx,
 	const char *host, const char *port, struct addrinfo *gai_hints)
 {
-	struct addrinfo *gai_result, *gai_iter;
+	struct addrinfo *gai_result = NULL, *gai_iter = NULL;
 	int err = getaddrinfo (host, port, gai_hints, &gai_result);
 	if (err)
 	{
 		char *address = format_host_port_pair (host, port);
-		print_error ("bind to %s failed: %s: %s",
+		print_error ("binding to %s failed: %s: %s",
 			address, "getaddrinfo", gai_strerror (err));
 		free (address);
 		return;
@@ -3984,6 +3995,21 @@ daemonize (struct server_context *ctx)
 	poller_post_fork (&ctx->poller);
 }

+static void
+setup_limits (void)
+{
+	struct rlimit limit;
+	if (getrlimit (RLIMIT_NOFILE, &limit))
+	{
+		print_warning ("%s: %s", "getrlimit", strerror (errno));
+		return;
+	}
+
+	limit.rlim_cur = limit.rlim_max;
+	if (setrlimit (RLIMIT_NOFILE, &limit))
+		print_warning ("%s: %s", "setrlimit", strerror (errno));
+}
+
 int
 main (int argc, char *argv[])
 {
@@ -4030,6 +4056,7 @@ main (int argc, char *argv[])

 	print_status (PROGRAM_NAME " " PROGRAM_VERSION " starting");
 	setup_signal_handlers ();
+	setup_limits ();
 	init_openssl ();

 	struct server_context ctx;
--- a/xF.c
+++ b/xF.c
@@ -0,0 +1,172 @@
+/*
+ * xF.c: a toothless IRC client frontend
+ *
+ * Copyright (c) 2022, Přemysl Eric Janouch <p@janouch.name>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "config.h"
+#define PROGRAM_NAME "xF"
+
+#include "common.c"
+#include "xC-proto.c"
+
+#include <X11/Xatom.h>
+#include <X11/Xlib.h>
+#include <X11/keysym.h>
+#include <X11/XKBlib.h>
+#include <X11/Xft/Xft.h>
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+static struct
+{
+	bool polling;
+	struct connector connector;
+	int socket;
+}
+g;
+
+static void
+on_connector_connecting (void *user_data, const char *address)
+{
+	(void) user_data;
+	print_status ("connecting to %s...", address);
+}
+
+static void
+on_connector_error (void *user_data, const char *error)
+{
+	(void) user_data;
+	print_status ("connection failed: %s", error);
+}
+
+static void
+on_connector_failure (void *user_data)
+{
+	(void) user_data;
+	exit_fatal ("giving up");
+}
+
+static void
+on_connector_connected (void *user_data, int socket, const char *hostname)
+{
+	(void) user_data;
+	(void) hostname;
+	g.polling = false;
+	g.socket = socket;
+}
+
+static void
+protocol_test (const char *host, const char *port)
+{
+	struct poller poller = {};
+	poller_init (&poller);
+
+	connector_init (&g.connector, &poller);
+	g.connector.on_connecting = on_connector_connecting;
+	g.connector.on_error      = on_connector_error;
+	g.connector.on_connected  = on_connector_connected;
+	g.connector.on_failure    = on_connector_failure;
+
+	connector_add_target (&g.connector, host, port);
+
+	g.polling = true;
+	while (g.polling)
+		poller_run (&poller);
+
+	connector_free (&g.connector);
+
+	struct str s = str_make ();
+	str_pack_u32 (&s, 0);
+	struct relay_command_message m = {};
+	m.data.hello.command = RELAY_COMMAND_HELLO;
+	m.data.hello.version = RELAY_VERSION;
+	if (!relay_command_message_serialize (&m, &s))
+		exit_fatal ("serialization failed");
+
+	uint32_t len = htonl (s.len - sizeof len);
+	memcpy (s.str, &len, sizeof len);
+	if (errno = 0, write (g.socket, s.str, s.len) != (ssize_t) s.len)
+		exit_fatal ("short send or error: %s", strerror (errno));
+
+	char buf[1 << 20] = "";
+	while (errno = 0, read (g.socket, &len, sizeof len) == sizeof len)
+	{
+		len = ntohl (len);
+		if (errno = 0, read (g.socket, buf, MIN (len, sizeof buf)) != len)
+			exit_fatal ("short read or error: %s", strerror (errno));
+
+		struct msg_unpacker r = msg_unpacker_make (buf, len);
+		struct relay_event_message m = {};
+		if (!relay_event_message_deserialize (&m, &r))
+			exit_fatal ("deserialization failed");
+		if (msg_unpacker_get_available (&r))
+			exit_fatal ("trailing data");
+
+		printf ("event: %d\n", m.data.event);
+		relay_event_message_free (&m);
+	}
+	exit_fatal ("short read or error: %s", strerror (errno));
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+int
+main (int argc, char *argv[])
+{
+	static const struct opt opts[] =
+	{
+		{ 'h', "help", NULL, 0, "display this help and exit" },
+		{ 'V', "version", NULL, 0, "output version information and exit" },
+		{ 0, NULL, NULL, 0, NULL }
+	};
+
+	struct opt_handler oh = opt_handler_make (argc, argv, opts,
+		"HOST:PORT", "X11 frontend for xC.");
+
+	int c;
+	while ((c = opt_handler_get (&oh)) != -1)
+	switch (c)
+	{
+	case 'h':
+		opt_handler_usage (&oh, stdout);
+		exit (EXIT_SUCCESS);
+	case 'V':
+		printf (PROGRAM_NAME " " PROGRAM_VERSION "\n");
+		exit (EXIT_SUCCESS);
+	default:
+		print_error ("wrong options");
+		opt_handler_usage (&oh, stderr);
+		exit (EXIT_FAILURE);
+	}
+
+	argc -= optind;
+	argv += optind;
+	if (argc != 1)
+	{
+		opt_handler_usage (&oh, stderr);
+		exit (EXIT_FAILURE);
+	}
+	opt_handler_free (&oh);
+
+	char *address = xstrdup (argv[0]);
+	const char *port = NULL, *host = tokenize_host_port (address, &port);
+	if (!port)
+		exit_fatal ("missing port number/service name");
+
+	// TODO: Actually implement an X11-based user interface.
+	protocol_test (host, port);
+	return 0;
+}
--- a/xF.svg
+++ b/xF.svg
@@ -0,0 +1,36 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg version="1.1" width="48" height="48" viewBox="0 0 48 48"
+   xmlns:xlink="http://www.w3.org/1999/xlink"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:svg="http://www.w3.org/2000/svg">
+
+  <defs>
+    <linearGradient id="background" x1="0" y1="0" x2="1" y2="1">
+      <stop stop-color="#808080" offset="0" />
+      <stop stop-color="#000000" offset="1" />
+    </linearGradient>
+    <!-- librsvg screws up the filter's orientation in a weird way
+         otherwise a larger blur value would look better -->
+    <filter id="shadow" color-interpolation-filters="sRGB">
+      <feOffset dy="0.5" />
+      <feGaussianBlur stdDeviation="0.5" />
+      <feComposite in2="SourceGraphic" operator="in" />
+    </filter>
+    <clipPath id="clip">
+      <rect x="-7" y="-10" width="14" height="20" />
+    </clipPath>
+  </defs>
+
+  <circle cx="24" cy="24" r="20"
+     fill="url(#background)" stroke="#404040" stroke-width="2" />
+
+  <g transform="rotate(-45 24 24)" filter="url(#shadow)">
+    <path d="m 12,25 h 24 v 11 h -5 v -8 h -4.5 v 6 h -5 v -6 h -9.5 z"
+       fill="#ffffff" />
+    <g stroke-width="4" transform="translate(24, 16)" clip-path="url(#clip)"
+       stroke="#ffffff">
+      <line x1="-8" x2="8" y1="-5" y2="5" />
+      <line x1="-8" x2="8" y1="5" y2="-5" />
+    </g>
+  </g>
+</svg>
--- a/xP.webp
+++ b/xP.webp
--- a/xP/.gitignore
+++ b/xP/.gitignore
@@ -0,0 +1,4 @@
+/xP
+/proto.go
+/public/proto.js
+/public/mithril.js
--- a/xP/Makefile
+++ b/xP/Makefile
@@ -0,0 +1,18 @@
+.POSIX:
+.SUFFIXES:
+
+outputs = xP proto.go public/proto.js public/mithril.js
+all: $(outputs) public/ircfmt.woff2
+
+xP: xP.go proto.go
+	go build -o $@
+proto.go: ../xC-gen-proto.awk ../xC-gen-proto-go.awk ../xC-proto
+	awk -f ../xC-gen-proto.awk -f ../xC-gen-proto-go.awk ../xC-proto > $@
+public/proto.js: ../xC-gen-proto.awk ../xC-gen-proto-js.awk ../xC-proto
+	awk -f ../xC-gen-proto.awk -f ../xC-gen-proto-js.awk ../xC-proto > $@
+public/ircfmt.woff2: gen-ircfmt.awk
+	awk -v Output=$@ -f gen-ircfmt.awk
+public/mithril.js:
+	curl -Lo $@ https://unpkg.com/mithril/mithril.js
+clean:
+	rm -f $(outputs)
--- a/xP/gen-ircfmt.awk
+++ b/xP/gen-ircfmt.awk
@@ -0,0 +1,89 @@
+# gen-ircfmt.awk: generate a supplementary font for IRC formatting characters
+#
+# Copyright (c) 2022, Přemysl Eric Janouch <p@janouch.name>
+# SPDX-License-Identifier: 0BSD
+#
+# Usage: awk -v Output=static/ircfmt.woff2 -f gen-ircfmt.awk
+# Clean up SVG byproducts yourself.
+
+BEGIN {
+	if (!Output) {
+		print "Error: you must specify the output filename"
+		exit 1
+	}
+}
+
+function glyph(name, code, path,    filename, actions, cmd) {
+	filename = Output "." name ".svg"
+
+	# Inkscape still does a terrible job at the stroke-to-path conversion.
+	actions = \
+		"select-by-id:group;" \
+		"selection-ungroup;" \
+		"select-clear;" \
+		"select-by-id:path;" \
+		"object-stroke-to-path;" \
+		"select-by-id:clip;" \
+		"path-intersection;" \
+		"select-all;" \
+		"path-combine;" \
+		"export-overwrite;" \
+		"export-filename:" filename ";" \
+		"export-do"
+
+	# These dimensions fit FontForge defaults, and happen to work well.
+	cmd = "inkscape --pipe --actions='" actions "'"
+	print "<?xml version='1.0' encoding='UTF-8' standalone='no'?>\n" \
+		"<svg version='1.1' xmlns='http://www.w3.org/2000/svg'\n" \
+		" width='1000' height='1000' viewBox='0 0 1000 1000'>\n" \
+		"  <rect x='0' y='0' width='1000' height='1000' />\n" \
+		"  <g id='group' transform='translate(200 200) scale(60, 60)'>\n" \
+		"    <rect id='clip' x='0' y='0' width='10' height='10' />\n" \
+		"    <path id='path' stroke-width='2' fill='none' stroke='#fff'\n" \
+		"     d='" path "' />\n" \
+		"  </g>\n" \
+		"</svg>\n" | cmd
+	close(cmd)
+
+	print "Select(0u" code ")\n" \
+		"Import('" filename "')" | FontForge
+}
+
+BEGIN {
+	FontForge = "fontforge -lang=ff -"
+	print "New()" | FontForge
+
+	# Designed a 10x10 raster, going for maximum simplicity.
+	glyph("B", "02", "m 6,5 c 0,0 2,0 2,2 0,2 -2,2 -2,2 h -3 v -8 h 2.5 c 0,0 2,0 2,2 0,2 -2,2 -2,2 h -2 Z")
+	glyph("C", "03", "m 7.6,7 A 3,4 0 0 1 4.25,8.875 3,4 0 0 1 2,5 3,4 0 0 1 4.25,1.125 3,4 0 0 1 7.6,3")
+	glyph("I", "1D", "m 3,9 h 4 m 0,-8 h -4 m 2,-1 v 10")
+	glyph("M", "11", "m 2,10 v -10 l 3,6 3,-6 v 10")
+	glyph("O", "0F", "m 1,9 l 8,-8 M 2,5 a 3,3 0 1 0 6,0 3,3 0 1 0 -6,0 z")
+	#glyph("R", "0F", "m 3,10 v -9 h 2 c 0,0 2.5,0 2.5,2.5 0,2.5 -2.5,2.5 -2.5,2.5 h -2 2.5 l 2.5,4.5")
+	glyph("S", "1E", "m 7.5,3 c 0,-1 -1,-2 -2.5,-2 -1.5,0 -2.5,1 -2.5,2 0,3 5,1 5,4 0,1 -1,2 -2.5,2 -1.5,0 -2.5,-1 -2.5,-2")
+	glyph("U", "1F", "m 2.5,0 v 6.5 c 0,1.5 1,2.5 2.5,2.5 1.5,0 2.5,-1 2.5,-2.5 v -6.5")
+	glyph("V", "16", "m 2,-1 3,11 3,-11")
+
+	# In practice, your typical browser font will overshoot its em box,
+	# so to make the display more cohesive, we need to do the same.
+	# Sadly, sf->use_typo_metrics can't be unset from FontForge script--
+	# this is necessary to prevent the caret from jumping upon the first
+	# inserted non-formatting character in xP's textarea.
+	# https://iamvdo.me/en/blog/css-font-metrics-line-height-and-vertical-align
+	print "SelectAll()\n" \
+		"Scale(115, 115, 0, 0)\n" \
+		"SetOS2Value('WinAscentIsOffset', 1)\n" \
+		"SetOS2Value('WinDescentIsOffset', 1)\n" \
+		"SetOS2Value('HHeadAscentIsOffset', 1)\n" \
+		"SetOS2Value('HHeadDescentIsOffset', 1)\n" \
+		"CorrectDirection()\n" \
+		"AutoWidth(100)\n" \
+		"AutoHint()\n" \
+		"AddExtrema()\n" \
+		"RoundToInt()\n" \
+		"SetFontNames('IRCFormatting-Regular'," \
+		" 'IRC Formatting', 'IRC Formatting Regular', 'Regular'," \
+		" 'Copyright (c) 2022, Premysl Eric Janouch')\n" \
+		"Generate('" Output "')\n" | FontForge
+	close(FontForge)
+}
--- a/xP/go.mod
+++ b/xP/go.mod
@@ -0,0 +1,10 @@
+module janouch.name/xK/xP
+
+go 1.18
+
+require nhooyr.io/websocket v1.8.7
+
+require (
+	github.com/klauspost/compress v1.15.9 // indirect
+	golang.org/x/sys v0.0.0-20210423082822-04245dca01da // indirect
+)
--- a/xP/go.sum
+++ b/xP/go.sum
@@ -0,0 +1,62 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/gin-contrib/sse v0.1.0 h1:Y/yl/+YNO8GZSjAhjMsSuLt29uWRFHdHYUb5lYOV9qE=
+github.com/gin-contrib/sse v0.1.0/go.mod h1:RHrZQHXnP2xjPF+u1gW/2HnVO7nvIa9PG3Gm+fLHvGI=
+github.com/gin-gonic/gin v1.6.3 h1:ahKqKTFpO5KTPHxWZjEdPScmYaGtLo8Y4DMHoEsnp14=
+github.com/gin-gonic/gin v1.6.3/go.mod h1:75u5sXoLsGZoRN5Sgbi1eraJ4GU3++wFwWzhwvtwp4M=
+github.com/go-playground/assert/v2 v2.0.1/go.mod h1:VDjEfimB/XKnb+ZQfWdccd7VUvScMdVu0Titje2rxJ4=
+github.com/go-playground/locales v0.13.0 h1:HyWk6mgj5qFqCT5fjGBuRArbVDfE4hi8+e8ceBS/t7Q=
+github.com/go-playground/locales v0.13.0/go.mod h1:taPMhCMXrRLJO55olJkUXHZBHCxTMfnGwq/HNwmWNS8=
+github.com/go-playground/universal-translator v0.17.0 h1:icxd5fm+REJzpZx7ZfpaD876Lmtgy7VtROAbHHXk8no=
+github.com/go-playground/universal-translator v0.17.0/go.mod h1:UkSxE5sNxxRwHyU+Scu5vgOQjsIJAF8j9muTVoKLVtA=
+github.com/go-playground/validator/v10 v10.2.0 h1:KgJ0snyC2R9VXYN2rneOtQcw5aHQB1Vv0sFl1UcHBOY=
+github.com/go-playground/validator/v10 v10.2.0/go.mod h1:uOYAAleCW8F/7oMFd6aG0GOhaH6EGOAJShg8Id5JGkI=
+github.com/gobwas/httphead v0.0.0-20180130184737-2c6c146eadee h1:s+21KNqlpePfkah2I+gwHF8xmJWRjooY+5248k6m4A0=
+github.com/gobwas/httphead v0.0.0-20180130184737-2c6c146eadee/go.mod h1:L0fX3K22YWvt/FAX9NnzrNzcI4wNYi9Yku4O0LKYflo=
+github.com/gobwas/pool v0.2.0 h1:QEmUOlnSjWtnpRGHF3SauEiOsy82Cup83Vf2LcMlnc8=
+github.com/gobwas/pool v0.2.0/go.mod h1:q8bcK0KcYlCgd9e7WYLm9LpyS+YeLd8JVDW6WezmKEw=
+github.com/gobwas/ws v1.0.2 h1:CoAavW/wd/kulfZmSIBt6p24n4j7tHgNVCjsfHVNUbo=
+github.com/gobwas/ws v1.0.2/go.mod h1:szmBTxLgaFppYjEmNtny/v3w89xOydFnnZMcgRRu/EM=
+github.com/golang/protobuf v1.3.3/go.mod h1:vzj43D7+SQXF/4pzW/hwtAqwc6iTitCiVSaWz5lYuqw=
+github.com/golang/protobuf v1.3.5 h1:F768QJ1E9tib+q5Sc8MkdJi1RxLTbRcTf8LJV56aRls=
+github.com/golang/protobuf v1.3.5/go.mod h1:6O5/vntMXwX2lRkT1hjjk0nAC1IDOTvTlVgjlRvqsdk=
+github.com/google/go-cmp v0.4.0 h1:xsAVV57WRhGj6kEIi8ReJzQlHHqcBYCElAvkovg3B/4=
+github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
+github.com/gorilla/websocket v1.4.1 h1:q7AeDBpnBk8AogcD4DSag/Ukw/KV+YhzLj2bP5HvKCM=
+github.com/gorilla/websocket v1.4.1/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
+github.com/json-iterator/go v1.1.9 h1:9yzud/Ht36ygwatGx56VwCZtlI/2AD15T1X2sjSuGns=
+github.com/json-iterator/go v1.1.9/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
+github.com/klauspost/compress v1.10.3/go.mod h1:aoV0uJVorq1K+umq18yTdKaF57EivdYsUV+/s2qKfXs=
+github.com/klauspost/compress v1.15.9 h1:wKRjX6JRtDdrE9qwa4b/Cip7ACOshUI4smpCQanqjSY=
+github.com/klauspost/compress v1.15.9/go.mod h1:PhcZ0MbTNciWF3rruxRgKxI5NkcHHrHUDtV4Yw2GlzU=
+github.com/leodido/go-urn v1.2.0 h1:hpXL4XnriNwQ/ABnpepYM/1vCLWNDfUNts8dX3xTG6Y=
+github.com/leodido/go-urn v1.2.0/go.mod h1:+8+nEpDfqqsY+g338gtMEUOtuK+4dEMhiQEgxpxOKII=
+github.com/mattn/go-isatty v0.0.12 h1:wuysRhFDzyxgEmMf5xjvJ2M9dZoWAXNNr5LSBS7uHXY=
+github.com/mattn/go-isatty v0.0.12/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU=
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+github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
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+github.com/modern-go/reflect2 v0.0.0-20180701023420-4b7aa43c6742/go.mod h1:bx2lNnkwVCuqBIxFjflWJWanXIb3RllmbCylyMrvgv0=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
+github.com/ugorji/go v1.1.7 h1:/68gy2h+1mWMrwZFeD1kQialdSzAb432dtpeJ42ovdo=
+github.com/ugorji/go v1.1.7/go.mod h1:kZn38zHttfInRq0xu/PH0az30d+z6vm202qpg1oXVMw=
+github.com/ugorji/go/codec v1.1.7 h1:2SvQaVZ1ouYrrKKwoSk2pzd4A9evlKJb9oTL+OaLUSs=
+github.com/ugorji/go/codec v1.1.7/go.mod h1:Ax+UKWsSmolVDwsd+7N3ZtXu+yMGCf907BLYF3GoBXY=
+golang.org/x/sys v0.0.0-20200116001909-b77594299b42/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210423082822-04245dca01da h1:b3NXsE2LusjYGGjL5bxEVZZORm/YEFFrWFjR8eFrw/c=
+golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
+golang.org/x/time v0.0.0-20191024005414-555d28b269f0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.8 h1:obN1ZagJSUGI0Ek/LBmuj4SNLPfIny3KsKFopxRdj10=
+gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+nhooyr.io/websocket v1.8.7 h1:usjR2uOr/zjjkVMy0lW+PPohFok7PCow5sDjLgX4P4g=
+nhooyr.io/websocket v1.8.7/go.mod h1:B70DZP8IakI65RVQ51MsWP/8jndNma26DVA/nFSCgW0=
--- a/xP/public/ircfmt.woff2
+++ b/xP/public/ircfmt.woff2
--- a/xP/public/xP.css
+++ b/xP/public/xP.css
@@ -0,0 +1,257 @@
+@font-face {
+	src: url('ircfmt.woff2') format('woff2');
+	font-family: 'IRC Formatting';
+	font-weight: normal;
+	font-style: normal;
+}
+body {
+	margin: 0;
+	padding: 0;
+	/* Firefox only renders C0 within the textarea, why? */
+	font-family: 'IRC Formatting', sans-serif;
+	font-size: clamp(0.5rem, 2vw, 1rem);
+}
+.xP {
+	display: flex;
+	flex-direction: column;
+	overflow: hidden;
+	height: 100vh;
+	/* https://caniuse.com/viewport-unit-variants */
+	height: 100dvh;
+}
+
+.overlay {
+	padding: .6em .9em;
+	background: #eee;
+	border: 1px outset #eee;
+	position: absolute;
+	left: 50%;
+	top: 50%;
+	transform: translate(-50%, -50%);
+	text-align: center;
+	z-index: 1;
+}
+.title, .status {
+	padding: .05em .3em;
+	background: #eee;
+
+	display: flex;
+	justify-content: space-between;
+	align-items: baseline;
+	column-gap: .3em;
+
+	position: relative;
+	border-top: 3px solid #ccc;
+	border-bottom: 2px solid #888;
+}
+.title {
+	/* To approximate right-aligned space-between. */
+	flex-direction: row-reverse;
+}
+.title:before, .status:before {
+	content: " ";
+	position: absolute;
+	left: 0;
+	right: 0;
+	height: 2px;
+	top: -2px;
+	background: #fff;
+}
+.title:after, .status:after {
+	content: " ";
+	position: absolute;
+	left: 0;
+	right: 0;
+	height: 1px;
+	bottom: -1px;
+	background: #ccc;
+}
+
+.toolbar {
+	display: flex;
+	align-items: baseline;
+	margin-right: -.3em;
+}
+.indicator {
+	margin: 0 .3em;
+}
+button {
+	font: inherit;
+	background: transparent;
+	border: 1px solid transparent;
+	padding: 0 .3em;
+}
+button:focus {
+	border: 1px dotted #000;
+}
+button:hover {
+	border-left: 1px solid #fff;
+	border-top: 1px solid #fff;
+	border-right: 1px solid #888;
+	border-bottom: 1px solid #888;
+}
+button:hover:active {
+	border-left: 1px solid #888;
+	border-top: 1px solid #888;
+	border-right: 1px solid #fff;
+	border-bottom: 1px solid #fff;
+}
+
+.middle {
+	flex: auto;
+	display: flex;
+	flex-direction: row;
+	overflow: hidden;
+}
+
+.list {
+	overflow-y: auto;
+	border-right: 2px solid #ccc;
+	min-width: 10em;
+	flex-shrink: 0;
+}
+.item {
+	padding: .05em .3em;
+	cursor: default;
+}
+.item.highlighted {
+	color: #ff5f00;
+}
+.item.activity {
+	font-weight: bold;
+}
+.item.current {
+	font-style: italic;
+	background: #eee;
+}
+
+/* Only Firefox currently supports align-content: safe end, thus this. */
+.buffer-container {
+	flex: auto;
+	display: flex;
+	flex-direction: column;
+	overflow: hidden;
+	position: relative;
+}
+.filler {
+	flex: auto;
+}
+.buffer {
+	display: grid;
+	grid-template-columns: max-content minmax(0, 1fr);
+	overflow-y: auto;
+}
+.log {
+	font-family: monospace;
+	overflow-y: auto;
+}
+.log, .content, .completions {
+	/* Note: https://bugs.chromium.org/p/chromium/issues/detail?id=1261435 */
+	white-space: break-spaces;
+	overflow-wrap: break-word;
+}
+.log, .buffer .content {
+	padding: .1em .3em;
+}
+
+.leaked {
+	opacity: 50%;
+}
+.date {
+	padding: .3em;
+	grid-column: span 2;
+	font-weight: bold;
+}
+.unread {
+	grid-column: span 2;
+	border-top: 1px solid #ff5f00;
+}
+.time {
+	padding: .1em .3em;
+	background: #f8f8f8;
+	color: #bbb;
+	border-right: 1px solid #ccc;
+}
+.time.hidden:after {
+	border-top: .2em dotted #ccc;
+	display: block;
+	width: 50%;
+	margin: 0 auto;
+	content: "";
+}
+.mark {
+	padding-right: .3em;
+	text-align: center;
+	display: inline-block;
+	min-width: 2em;
+}
+.mark.error {
+	color: red;
+}
+.mark.join {
+	color: green;
+}
+.mark.part {
+	color: red;
+}
+.mark.action {
+	color: darkred;
+}
+.content .b {
+	font-weight: bold;
+}
+.content .i {
+	font-style: italic;
+}
+.content .u {
+	text-decoration: underline;
+}
+.content .s {
+	text-decoration: line-through;
+}
+.content .m {
+	font-family: monospace;
+}
+
+.completions {
+	position: absolute;
+	left: 0;
+	right: 0;
+	bottom: 0;
+	background: #fff;
+	padding: .05em .3em;
+	border-top: 1px solid #888;
+
+	max-height: 50%;
+	display: flex;
+	flex-flow: column wrap;
+	column-gap: .6em;
+	overflow-x: auto;
+}
+.input {
+	flex-shrink: 0;
+	border: 2px inset #eee;
+	overflow: hidden;
+	resize: vertical;
+	display: flex;
+}
+.input:focus-within {
+	border-color: #ff5f00;
+}
+.prompt {
+	padding: .05em .3em;
+	border-right: 1px solid #ccc;
+	background: #f8f8f8;
+	font-weight: bold;
+}
+textarea {
+	font: inherit;
+	padding: .05em .3em;
+	margin: 0;
+	border: 0;
+	flex-grow: 1;
+	resize: none;
+}
+textarea:focus {
+	outline: none;
+}
--- a/xP/public/xP.js
+++ b/xP/public/xP.js
--- a/xP/xP.go
+++ b/xP/xP.go
@@ -0,0 +1,299 @@
+// Copyright (c) 2022, Přemysl Eric Janouch <p@janouch.name>
+// SPDX-License-Identifier: 0BSD
+
+package main
+
+import (
+	"bufio"
+	"context"
+	"encoding/binary"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"html/template"
+	"io"
+	"log"
+	"net"
+	"net/http"
+	"os"
+	"time"
+
+	"nhooyr.io/websocket"
+)
+
+var (
+	debug = flag.Bool("debug", false, "enable debug output")
+
+	addressBind    string
+	addressConnect string
+	addressWS      string
+)
+
+// -----------------------------------------------------------------------------
+
+func relayReadFrame(r io.Reader) []byte {
+	var length uint32
+	if err := binary.Read(r, binary.BigEndian, &length); err != nil {
+		log.Println("Event receive failed: " + err.Error())
+		return nil
+	}
+	b := make([]byte, length)
+	if _, err := io.ReadFull(r, b); err != nil {
+		log.Println("Event receive failed: " + err.Error())
+		return nil
+	}
+
+	if *debug {
+		log.Printf("<? %v\n", b)
+
+		var m RelayEventMessage
+		if after, ok := m.ConsumeFrom(b); !ok {
+			log.Println("Event deserialization failed")
+			return nil
+		} else if len(after) != 0 {
+			log.Println("Event deserialization failed: trailing data")
+			return nil
+		}
+
+		j, err := m.MarshalJSON()
+		if err != nil {
+			log.Println("Event marshalling failed: " + err.Error())
+			return nil
+		}
+
+		log.Printf("<- %s\n", j)
+	}
+	return b
+}
+
+func relayMakeReceiver(ctx context.Context, conn net.Conn) <-chan []byte {
+	// The usual event message rarely gets above 1 kilobyte,
+	// thus this is set to buffer up at most 1 megabyte or so.
+	p := make(chan []byte, 1000)
+	r := bufio.NewReaderSize(conn, 65536)
+	go func() {
+		defer close(p)
+		for {
+			j := relayReadFrame(r)
+			if j == nil {
+				return
+			}
+			select {
+			case p <- j:
+			case <-ctx.Done():
+				return
+			}
+		}
+	}()
+	return p
+}
+
+func relayWriteJSON(conn net.Conn, j []byte) bool {
+	var m RelayCommandMessage
+	if err := json.Unmarshal(j, &m); err != nil {
+		log.Println("Command unmarshalling failed: " + err.Error())
+		return false
+	}
+
+	b, ok := m.AppendTo(make([]byte, 4))
+	if !ok {
+		log.Println("Command serialization failed")
+		return false
+	}
+	binary.BigEndian.PutUint32(b[:4], uint32(len(b)-4))
+	if _, err := conn.Write(b); err != nil {
+		log.Println("Command send failed: " + err.Error())
+		return false
+	}
+
+	if *debug {
+		log.Printf("-> %v\n", b)
+	}
+	return true
+}
+
+// -----------------------------------------------------------------------------
+
+func clientReadJSON(ctx context.Context, ws *websocket.Conn) []byte {
+	t, j, err := ws.Read(ctx)
+	if err != nil {
+		log.Println("Command receive failed: " + err.Error())
+		return nil
+	}
+	if t != websocket.MessageText {
+		log.Println(
+			"Command receive failed: " + "binary messages are not supported")
+		return nil
+	}
+
+	if *debug {
+		log.Printf("?> %s\n", j)
+	}
+	return j
+}
+
+func clientWriteBinary(ctx context.Context, ws *websocket.Conn, b []byte) bool {
+	if err := ws.Write(ctx, websocket.MessageBinary, b); err != nil {
+		log.Println("Event send failed: " + err.Error())
+		return false
+	}
+	return true
+}
+
+func clientWriteError(ctx context.Context, ws *websocket.Conn, err error) bool {
+	b, ok := (&RelayEventMessage{
+		EventSeq: 0,
+		Data: RelayEventData{
+			Interface: RelayEventDataError{
+				Event:      RelayEventError,
+				CommandSeq: 0,
+				Error:      err.Error(),
+			},
+		},
+	}).AppendTo(nil)
+	if ok {
+		log.Println("Event serialization failed")
+		return false
+	}
+	return clientWriteBinary(ctx, ws, b)
+}
+
+func handleWS(w http.ResponseWriter, r *http.Request) {
+	ws, err := websocket.Accept(w, r, &websocket.AcceptOptions{
+		InsecureSkipVerify: true,
+		// Note that Safari can be broken with compression.
+		CompressionMode: websocket.CompressionContextTakeover,
+		// This is for the payload; set higher to avoid overhead.
+		CompressionThreshold: 64 << 10,
+	})
+	if err != nil {
+		log.Println("Client rejected: " + err.Error())
+		return
+	}
+	defer ws.Close(websocket.StatusGoingAway, "Goodbye")
+
+	ctx, cancel := context.WithCancel(r.Context())
+	defer cancel()
+
+	conn, err := net.Dial("tcp", addressConnect)
+	if err != nil {
+		log.Println("Connection failed: " + err.Error())
+		clientWriteError(ctx, ws, err)
+		return
+	}
+	defer conn.Close()
+
+	// To decrease latencies, events are received and decoded in parallel
+	// to their sending, and we try to batch them together.
+	relayFrames := relayMakeReceiver(ctx, conn)
+	batchFrames := func() []byte {
+		batch, ok := <-relayFrames
+		if !ok {
+			return nil
+		}
+	Batch:
+		for {
+			select {
+			case b, ok := <-relayFrames:
+				if !ok {
+					break Batch
+				}
+				batch = append(batch, b...)
+			default:
+				break Batch
+			}
+		}
+		return batch
+	}
+
+	// We don't need to intervene, so it's just two separate pipes so far.
+	go func() {
+		defer cancel()
+		for {
+			j := clientReadJSON(ctx, ws)
+			if j == nil {
+				return
+			}
+			relayWriteJSON(conn, j)
+		}
+	}()
+	go func() {
+		defer cancel()
+		for {
+			b := batchFrames()
+			if b == nil {
+				return
+			}
+			clientWriteBinary(ctx, ws, b)
+		}
+	}()
+	<-ctx.Done()
+}
+
+// -----------------------------------------------------------------------------
+
+var staticHandler = http.FileServer(http.Dir("."))
+
+var page = template.Must(template.New("/").Parse(`<!DOCTYPE html>
+<html>
+<head>
+	<title>xP</title>
+	<meta charset="utf-8" />
+	<meta name="viewport" content="width=device-width, initial-scale=1">
+	<link rel="stylesheet" href="xP.css" />
+</head>
+<body>
+	<script src="mithril.js">
+	</script>
+	<script>
+	let proxy = '{{ . }}'
+	</script>
+	<script type="module" src="xP.js">
+	</script>
+</body>
+</html>`))
+
+func handleDefault(w http.ResponseWriter, r *http.Request) {
+	if r.URL.Path != "/" {
+		staticHandler.ServeHTTP(w, r)
+		return
+	}
+
+	wsURI := addressWS
+	if wsURI == "" {
+		wsURI = fmt.Sprintf("ws://%s/ws", r.Host)
+	}
+	if err := page.Execute(w, wsURI); err != nil {
+		log.Println("Template execution failed: " + err.Error())
+	}
+}
+
+func main() {
+	flag.Usage = func() {
+		fmt.Fprintf(flag.CommandLine.Output(),
+			"Usage: %s [OPTION...] BIND CONNECT [WSURI]\n\n", os.Args[0])
+		flag.PrintDefaults()
+	}
+
+	flag.Parse()
+	if flag.NArg() < 2 || flag.NArg() > 3 {
+		flag.Usage()
+		os.Exit(1)
+	}
+
+	addressBind, addressConnect = flag.Arg(0), flag.Arg(1)
+	if flag.NArg() > 2 {
+		addressWS = flag.Arg(2)
+	}
+
+	http.Handle("/ws", http.HandlerFunc(handleWS))
+	http.Handle("/", http.HandlerFunc(handleDefault))
+
+	s := &http.Server{
+		Addr:           addressBind,
+		ReadTimeout:    60 * time.Second,
+		WriteTimeout:   60 * time.Second,
+		MaxHeaderBytes: 32 << 10,
+	}
+	log.Fatal(s.ListenAndServe())
+}