From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Matthew Leach Newsgroups: gmane.emacs.devel Subject: Re: [PATCH v4] Add systemd socket launching support Date: Thu, 07 Apr 2016 16:53:59 +0100 Message-ID: <87pou11kko.fsf@mattleach.net> References: <87lh4t2xun.fsf@mattleach.net> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1460044498 16405 80.91.229.3 (7 Apr 2016 15:54:58 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 7 Apr 2016 15:54:58 +0000 (UTC) Cc: Eli Zaretskii , emacs-devel To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Thu Apr 07 17:54:48 2016 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1aoCGY-0000sZ-Ce for ged-emacs-devel@m.gmane.org; Thu, 07 Apr 2016 17:54:42 +0200 Original-Received: from localhost ([::1]:50802 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aoCGU-0000BX-K7 for ged-emacs-devel@m.gmane.org; Thu, 07 Apr 2016 11:54:38 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:56153) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aoCG8-00005L-3I for emacs-devel@gnu.org; Thu, 07 Apr 2016 11:54:18 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aoCG5-0002UC-Qy for emacs-devel@gnu.org; Thu, 07 Apr 2016 11:54:16 -0400 Original-Received: from mx0.mattleach.net ([176.58.118.143]:49666) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aoCG0-0002Sl-VU; Thu, 07 Apr 2016 11:54:09 -0400 Original-Received: by mx0.mattleach.net (Postfix, from userid 99) id 2D4BF6222E; Thu, 7 Apr 2016 16:54:08 +0100 (BST) Original-Received: from spline.mattleach.net (unknown [213.86.103.11]) by mx0.mattleach.net (Postfix) with ESMTPSA id E82A36222C; Thu, 7 Apr 2016 16:53:57 +0100 (BST) In-Reply-To: <87lh4t2xun.fsf@mattleach.net> (Matthew Leach's message of "Mon, 04 Apr 2016 16:32:48 +0100") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1.50 (gnu/linux) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 176.58.118.143 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:202802 Archived-At: Hi Stefan, I've been thinking about what you said regarding reducing the coupling this set of patches has to systemd. I'm thinking that having a C (non-lisp) function that can be called to set the FD that has been passed to Emacs could work. That way, we provide an interface for other socket-passing libraries to call. What are your thoughts? Matthew Leach writes: > Hi all, > > Here is a new version of the systemd integration patches. Main changes > include, documentation updates (document that the :use-systemd-socket > option may be silently ignored and include systemd units in the Emacs > manual), and rename config.h macro to HAVE_LIBSYSTEMD. > > Feedback & comments welcome! > > Thanks, > -- > Matt > > From d5972913f8c6ed8b4de6054e14395a373f2ee96e Mon Sep 17 00:00:00 2001 > From: Matthew Leach > Date: Sat, 26 Mar 2016 16:41:17 +0000 > Subject: [PATCH 1/4] Check for libsystemd when building Emacs. > > * configure.ac: Add new default-on option systemd and check for > libsystemd at configure time. > * src/Makefile.in: Add libsystemd library and C flags to the Emacs > compilation options. > --- > configure.ac | 13 +++++++++++++ > src/Makefile.in | 6 +++++- > 2 files changed, 18 insertions(+), 1 deletion(-) > > diff --git a/configure.ac b/configure.ac > index f3846f4..f53c670 100644 > --- a/configure.ac > +++ b/configure.ac > @@ -330,6 +330,7 @@ OPTION_DEFAULT_ON([tiff],[don't compile with TIFF image support]) > OPTION_DEFAULT_ON([gif],[don't compile with GIF image support]) > OPTION_DEFAULT_ON([png],[don't compile with PNG image support]) > OPTION_DEFAULT_ON([rsvg],[don't compile with SVG image support]) > +OPTION_DEFAULT_ON([libsystemd],[don't compile with libsystemd support]) > OPTION_DEFAULT_OFF([cairo],[compile with Cairo drawing (experimental)]) > OPTION_DEFAULT_ON([xml2],[don't compile with XML parsing support]) > OPTION_DEFAULT_ON([imagemagick],[don't compile with ImageMagick image support]) > @@ -2716,6 +2717,18 @@ fi > AC_SUBST(LIBGNUTLS_LIBS) > AC_SUBST(LIBGNUTLS_CFLAGS) > > +HAVE_LIBSYSTEMD=no > +if test "${with_libsystemd}" = "yes" ; then > + EMACS_CHECK_MODULES([LIBSYSTEMD], [libsystemd >= 226], > + [HAVE_LIBSYSTEMD=yes], [HAVE_LIBSYSTEMD=no]) > + if test "${HAVE_LIBSYSTEMD}" = "yes"; then > + AC_DEFINE(HAVE_LIBSYSTEMD, 1, [Define if using libsystemd.]) > + fi > +fi > + > +AC_SUBST(LIBSYSTEMD_LIBS) > +AC_SUBST(LIBSYSTEMD_CFLAGS) > + > NOTIFY_OBJ= > NOTIFY_SUMMARY=no > > diff --git a/src/Makefile.in b/src/Makefile.in > index c290a60..fc9360a 100644 > --- a/src/Makefile.in > +++ b/src/Makefile.in > @@ -307,6 +307,9 @@ LIBSELINUX_LIBS = @LIBSELINUX_LIBS@ > LIBGNUTLS_LIBS = @LIBGNUTLS_LIBS@ > LIBGNUTLS_CFLAGS = @LIBGNUTLS_CFLAGS@ > > +LIBSYSTEMD_LIBS = @LIBSYSTEMD_LIBS@ > +LIBSYSTEMD_CFLAGS = @LIBSYSTEMD_CFLAGS@ > + > INTERVALS_H = dispextern.h intervals.h composite.h > > GETLOADAVG_LIBS = @GETLOADAVG_LIBS@ > @@ -372,6 +375,7 @@ ALL_CFLAGS=-Demacs $(MYCPPFLAGS) -I. -I$(srcdir) \ > $(WEBKIT_CFLAGS) \ > $(SETTINGS_CFLAGS) $(FREETYPE_CFLAGS) $(FONTCONFIG_CFLAGS) \ > $(LIBOTF_CFLAGS) $(M17N_FLT_CFLAGS) $(DEPFLAGS) \ > + $(LIBSYSTEMD_CFLAGS) \ > $(LIBGNUTLS_CFLAGS) $(NOTIFY_CFLAGS) $(CAIRO_CFLAGS) \ > $(WARN_CFLAGS) $(WERROR_CFLAGS) $(CFLAGS) > ALL_OBJC_CFLAGS=$(ALL_CFLAGS) $(GNU_OBJC_CFLAGS) > @@ -489,7 +493,7 @@ LIBES = $(LIBS) $(W32_LIBS) $(LIBS_GNUSTEP) $(LIBX_BASE) $(LIBIMAGE) \ > $(LIBS_TERMCAP) $(GETLOADAVG_LIBS) $(SETTINGS_LIBS) $(LIBSELINUX_LIBS) \ > $(FREETYPE_LIBS) $(FONTCONFIG_LIBS) $(LIBOTF_LIBS) $(M17N_FLT_LIBS) \ > $(LIBGNUTLS_LIBS) $(LIB_PTHREAD) $(GETADDRINFO_A_LIBS) \ > - $(NOTIFY_LIBS) $(LIB_MATH) $(LIBZ) $(LIBMODULES) > + $(NOTIFY_LIBS) $(LIB_MATH) $(LIBZ) $(LIBMODULES) $(LIBSYSTEMD_LIBS) > > $(leimdir)/leim-list.el: bootstrap-emacs$(EXEEXT) > $(MAKE) -C ../leim leim-list.el EMACS="$(bootstrap_exe)" > -- > 2.7.4 > > From 5f5ba1ce322a0c4b5ff7f2c7eb939928aec799c7 Mon Sep 17 00:00:00 2001 > From: Matthew Leach > Date: Sat, 26 Mar 2016 18:50:14 +0000 > Subject: [PATCH 2/4] Read the number of sockets passed by systemd. > > * src/emacs.c (systemd_socket): New variable for storing the socket > descriptor passed in by systemd. > (main): Call sd_listen_fds to read the number of sockets passed. > --- > src/emacs.c | 29 +++++++++++++++++++++++++++++ > 1 file changed, 29 insertions(+) > > diff --git a/src/emacs.c b/src/emacs.c > index 95d1905..67906e8 100644 > --- a/src/emacs.c > +++ b/src/emacs.c > @@ -56,6 +56,11 @@ along with GNU Emacs. If not, see . */ > #include > #endif > > +#ifdef HAVE_LIBSYSTEMD > +#include > +#include > +#endif /* HAVE_LIBSYSTEMD */ > + > #ifdef HAVE_WINDOW_SYSTEM > #include TERM_HEADER > #endif /* HAVE_WINDOW_SYSTEM */ > @@ -195,6 +200,12 @@ int daemon_pipe[2]; > HANDLE w32_daemon_event; > #endif > > +#ifdef HAVE_LIBSYSTEMD > +/* The socket descriptor passed by systemd. If nothing has been > + passed, this will be 0. */ > +int systemd_socket = 0; > +#endif /* HAVE_LIBSYSTEMD */ > + > /* Save argv and argc. */ > char **initial_argv; > int initial_argc; > @@ -997,6 +1008,24 @@ main (int argc, char **argv) > exit (1); > } > > +#ifdef HAVE_LIBSYSTEMD > + /* Read the number of sockets passed through by systemd. */ > + systemd_socket = sd_listen_fds(1); > + > + if (systemd_socket > 1) > + { > + fprintf (stderr, "\nWarning: systemd has passed more than one socket to the Emacs process.\n\ > +Try adding 'Accept=false' in the Emacs socket unit file.\n"); > + systemd_socket = 0; > + } > + else if (systemd_socket == 1 && > + sd_is_socket (SD_LISTEN_FDS_START, > + AF_UNSPEC, SOCK_STREAM, 1) >= 0) > + systemd_socket = SD_LISTEN_FDS_START; > + else > + systemd_socket = 0; > +#endif /* HAVE_LIBSYSTEMD */ > + > #ifndef DAEMON_MUST_EXEC > #ifdef USE_GTK > fprintf (stderr, "\nWarning: due to a long standing Gtk+ bug\nhttp://bugzilla.gnome.org/show_bug.cgi?id=85715\n\ > -- > 2.7.4 > > From 2ed8471b2c6157e5639570d865db98e9fe33fb36 Mon Sep 17 00:00:00 2001 > From: Matthew Leach > Date: Sat, 26 Mar 2016 19:37:10 +0000 > Subject: [PATCH 3/4] Allow network processes to be made with a pre-allocated > fd. > > * src/process.c (connect_network_socket): Allow a pre-allocated > socket descriptor to be used if passed to Emacs, avoiding the call > to socket() and bind(). > (Fmake_network_process): Allow users to pass in :use-systemd-socket on > the parameter plist to use a socket descriptor that has been passed to > Emacs from systemd. > (wait_reading_process_output): Call socket() & bind() every time. > (syms_of_process): New symbol ":use-passed-socket". > * doc/lispref/processes.texi (Network Processes): Document new > `make-network-process' option ':use-systemd-socket'. > --- > doc/lispref/processes.texi | 7 +++++++ > src/process.c | 39 ++++++++++++++++++++++++++++++++------- > 2 files changed, 39 insertions(+), 7 deletions(-) > > diff --git a/doc/lispref/processes.texi b/doc/lispref/processes.texi > index 8d3df55..83c1aa2 100644 > --- a/doc/lispref/processes.texi > +++ b/doc/lispref/processes.texi > @@ -2367,6 +2367,13 @@ automatically for the given @var{host} and @var{service}. > ignored. @code{ipv4} and @code{ipv6} specify to use IPv4 and IPv6, > respectively. > > +@item :use-systemd-socket @var{use-systemd-socket} > +If @var{use-systemd-socket} is non-@code{nil} use any sockets passed > +by systemd instead of allocating one. This is used by the Emacs > +server code to allow on-demand socket activation. If Emacs hasn't > +been compiled with libsystemd support or systemd didn't pass a socket, > +this option is silently ignored. > + > @item :local @var{local-address} > For a server process, @var{local-address} is the address to listen on. > It overrides @var{family}, @var{host} and @var{service}, so you > diff --git a/src/process.c b/src/process.c > index 198e7de..85ffd25 100644 > --- a/src/process.c > +++ b/src/process.c > @@ -3075,7 +3075,8 @@ finish_after_tls_connection (Lisp_Object proc) > #endif > > static void > -connect_network_socket (Lisp_Object proc, Lisp_Object ip_addresses) > +connect_network_socket (Lisp_Object proc, Lisp_Object ip_addresses, > + Lisp_Object use_systemd_socket_p) > { > ptrdiff_t count = SPECPDL_INDEX (); > ptrdiff_t count1; > @@ -3089,6 +3090,16 @@ connect_network_socket (Lisp_Object proc, Lisp_Object ip_addresses) > struct Lisp_Process *p = XPROCESS (proc); > Lisp_Object contact = p->childp; > int optbits = 0; > + int systemd_socket_descriptor = 0; > + > +#ifdef HAVE_LIBSYSTEMD > + if (!NILP (use_systemd_socket_p)) > + { > + extern int systemd_socket; > + systemd_socket_descriptor = systemd_socket; > + } > +#endif /* HAVE_LIBSYSTEMD */ > + > > /* Do this in case we never enter the while-loop below. */ > count1 = SPECPDL_INDEX (); > @@ -3109,7 +3120,11 @@ connect_network_socket (Lisp_Object proc, Lisp_Object ip_addresses) > sa = xmalloc (addrlen); > conv_lisp_to_sockaddr (family, ip_address, sa, addrlen); > > - s = socket (family, p->socktype | SOCK_CLOEXEC, p->ai_protocol); > + if (systemd_socket_descriptor) > + s = systemd_socket_descriptor; > + else > + s = socket (family, p->socktype | SOCK_CLOEXEC, p->ai_protocol); > + > if (s < 0) > { > xerrno = errno; > @@ -3168,8 +3183,11 @@ connect_network_socket (Lisp_Object proc, Lisp_Object ip_addresses) > report_file_error ("Cannot set reuse option on server socket", Qnil); > } > > - if (bind (s, sa, addrlen)) > - report_file_error ("Cannot bind server socket", Qnil); > + /* If we are passed a socket descriptor from systemd, it is > + already bound. */ > + if (!systemd_socket_descriptor) > + if (bind (s, sa, addrlen)) > + report_file_error ("Cannot bind server socket", Qnil); > > #ifdef HAVE_GETSOCKNAME > if (p->port == 0) > @@ -3534,6 +3552,11 @@ The following network options can be specified for this connection: > (this is allowed by default for a server process). > :bindtodevice NAME -- bind to interface NAME. Using this may require > special privileges on some systems. > +:use-systemd-socket BOOL -- Use any pre-allocated sockets that have > + been passed to Emacs by systemd. If Emacs > + hasn't been compiled with libsystemd support > + or systemd didn't pass a socket, this option > + is silently ignored. > > Consult the relevant system programmer's manual pages for more > information on using these options. > @@ -3578,7 +3601,7 @@ usage: (make-network-process &rest ARGS) */) > EMACS_INT port = 0; > Lisp_Object tem; > Lisp_Object name, buffer, host, service, address; > - Lisp_Object filter, sentinel; > + Lisp_Object filter, sentinel, use_systemd_socket_p; > Lisp_Object ip_addresses = Qnil; > int socktype; > int family = -1; > @@ -3618,6 +3641,7 @@ usage: (make-network-process &rest ARGS) */) > buffer = Fplist_get (contact, QCbuffer); > filter = Fplist_get (contact, QCfilter); > sentinel = Fplist_get (contact, QCsentinel); > + use_systemd_socket_p = Fplist_get (contact, QCuse_systemd_socket); > > CHECK_STRING (name); > > @@ -3914,7 +3938,7 @@ usage: (make-network-process &rest ARGS) */) > } > #endif > > - connect_network_socket (proc, ip_addresses); > + connect_network_socket (proc, ip_addresses, use_systemd_socket_p); > return proc; > } > > @@ -4848,7 +4872,7 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd, > { > Lisp_Object ip_addresses = check_for_dns (aproc); > if (!NILP (ip_addresses) && !EQ (ip_addresses, Qt)) > - connect_network_socket (aproc, ip_addresses); > + connect_network_socket (aproc, ip_addresses, Qnil); > else > retry_for_async = true; > } > @@ -7837,6 +7861,7 @@ syms_of_process (void) > DEFSYM (QCserver, ":server"); > DEFSYM (QCnowait, ":nowait"); > DEFSYM (QCsentinel, ":sentinel"); > + DEFSYM (QCuse_systemd_socket, ":use-systemd-socket"); > DEFSYM (QCtls_parameters, ":tls-parameters"); > DEFSYM (Qnsm_verify_connection, "nsm-verify-connection"); > DEFSYM (QClog, ":log"); > -- > 2.7.4 > > From a09250b5c53c8da1157135f1ace2ecd4748d6510 Mon Sep 17 00:00:00 2001 > From: Matthew Leach > Date: Sat, 26 Mar 2016 20:43:26 +0000 > Subject: [PATCH 4/4] When Emacs is passed a socket descriptor, make the server > listen on it. > > * lisp/server.el (server-start): Set :use-systemd-socket to `t' when > calling `make-network-process'. > * etc/NEWS: Document new systemd functionality and build option to > disable it. > * doc/emacs/misc.texi (Emacs Server): Document systemd socket passing > functionality and provide systemd unit examples. > --- > doc/emacs/misc.texi | 37 +++++++++++++++++++++++++++++++++++++ > etc/NEWS | 7 +++++++ > lisp/server.el | 1 + > 3 files changed, 45 insertions(+) > > diff --git a/doc/emacs/misc.texi b/doc/emacs/misc.texi > index b5a2150..2622592 100644 > --- a/doc/emacs/misc.texi > +++ b/doc/emacs/misc.texi > @@ -1580,6 +1580,43 @@ option. @xref{Initial Options}. When Emacs is started this way, it > calls @code{server-start} after initialization, and returns control to > the calling terminal instead of opening an initial frame; it then > waits in the background, listening for edit requests. > + > +@cindex socket activation, systemd, Emacs > +@item > +If Emacs has been built with @command{systemd} support, the Emacs > +server can be started by socket activation. The @command{systemd} > +service creates a socket and listens for connections on it; when > +@command{emacsclient} connects to it for the first time, > +@command{systemd} can launch the Emacs server and hands over the > +socket to it for servicing @command{emacsclient} connections. A setup > +to use this functionality could be: > + > +@file{~/.config/systemd/user/emacs.service}: > +@example > +[Unit] > +Description=Emacs > + > +[Service] > +Type=forking > +ExecStart=/path/to/emacs --daemon > +ExecStop=/path/to/emacsclient --eval "(kill-emacs)" > +Restart=always > + > +[Install] > +WantedBy=default.target > +@end example > + > +@file{~/.config/systemd/user/emacs.socket}: > +@example > +[Socket] > +ListenStream=/path/to/.emacs.socket > + > +[Install] > +WantedBy=sockets.target > +@end example > + > +The @code{ListenStream} path will be the path that Emacs listens for > +connections from @command{emacsclient}; this is a file of your choice. > @end itemize > > @cindex @env{TEXEDIT} environment variable > diff --git a/etc/NEWS b/etc/NEWS > index 66777e9..9afed5b 100644 > --- a/etc/NEWS > +++ b/etc/NEWS > @@ -26,6 +26,13 @@ otherwise leave it unmarked. > * Installation Changes in Emacs 25.2 > > +++ > +** Emacs now has systemd support. This allows socket based > +activation, where systemd can invoke the Emacs process upon a > +socket connection and hand over the socket to Emacs. Emacs will > +use this socket for communicating with the emacsclient program. > +This can be disabled with the new configure option > +'--disable-systemd'. > + > ** New configure option '--disable-build-details' attempts to build an > Emacs that is more likely to be reproducible; that is, if you build > and install Emacs twice, the second Emacs is a copy of the first. > diff --git a/lisp/server.el b/lisp/server.el > index 5243820..2c9113c 100644 > --- a/lisp/server.el > +++ b/lisp/server.el > @@ -655,6 +655,7 @@ server or call `\\[server-force-delete]' to forcibly disconnect it.")) > :noquery t > :sentinel #'server-sentinel > :filter #'server-process-filter > + :use-systemd-socket t > ;; We must receive file names without being decoded. > ;; Those are decoded by server-process-filter according > ;; to file-name-coding-system. Also don't get -- Matt