[Emacs-diffs] master 531c9a4: Minor fixups for external socket launching

[Paul Eggert]

branch: master
commit 531c9a43ad91aa979f02651b135f9e7c3446996f
Author: Paul Eggert <address@hidden>
Commit: Paul Eggert <address@hidden>

    Minor fixups for external socket launching
    
    * configure.ac (HAVE_LIBSYSTEMD): Change earliest version to 222.
    * doc/emacs/misc.texi (Emacs Server):
    * etc/NEWS: Spelling and doc fixes.
    * src/emacs.c (main) [HAVE_LIBSYSTEMD]:
    Check for sd_is_socket returning positive, not zero.
    * src/process.c (external_sock_fd): Instead of initializing here ...
    (init_process_emacs): ... initialize it here, so that it does the
    right thing after dump/restore.
    (connect_network_socket): Simplify socket_to_use test.
---
 configure.ac        |    5 ++++-
 doc/emacs/misc.texi |    2 +-
 etc/NEWS            |   12 ++++++------
 src/emacs.c         |   26 ++++++++++++--------------
 src/process.c       |   35 ++++++++++++++++-------------------
 5 files changed, 39 insertions(+), 41 deletions(-)

diff --git a/configure.ac b/configure.ac
index 54e9ec5..0f6f650 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2735,7 +2735,10 @@ AC_SUBST(LIBGNUTLS_CFLAGS)
 
 HAVE_LIBSYSTEMD=no
 if test "${with_libsystemd}" = "yes" ; then
-  EMACS_CHECK_MODULES([LIBSYSTEMD], [libsystemd >= 226],
+  dnl This code has been tested with libsystemd 222 and later.
+  dnl FIXME: Find the earliest version number for which Emacs should work,
+  dnl and change '222' to that number.
+  EMACS_CHECK_MODULES([LIBSYSTEMD], [libsystemd >= 222],
     [HAVE_LIBSYSTEMD=yes], [HAVE_LIBSYSTEMD=no])
   if test "${HAVE_LIBSYSTEMD}" = "yes"; then
     AC_DEFINE(HAVE_LIBSYSTEMD, 1, [Define if using libsystemd.])
diff --git a/doc/emacs/misc.texi b/doc/emacs/misc.texi
index 775cda9..20f2d66 100644
--- a/doc/emacs/misc.texi
+++ b/doc/emacs/misc.texi
@@ -1586,7 +1586,7 @@ waits in the background, listening for edit requests.
 An external process can invoke the Emacs server when a connection
 event occurs upon a specified socket and pass the socket to the new
 Emacs server process.  An instance of this is @command{systemd}'s
-socket functionaly: the @command{systemd} service creates a socket and
+socket functionality: 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 hand over the socket to it for servicing @command{emacsclient}
diff --git a/etc/NEWS b/etc/NEWS
index ecb52c1..2373347 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -32,12 +32,12 @@ the default in developer builds.  As before, use
 '--enable-gcc-warnings' to stop the build if GCC issues warnings.
 
 +++
-** Emacs server now has socket-launching support.  This allows socket
-based activation, where an external process can invoke the Emacs
-server process upon a socket connection event and hand over the socket
-to Emacs.  Emacs will use this socket for servicing emacsclient
-commands.  systemd can make use of this new functionally but can be
-disabled with the configure option '--disable-libsystemd'.
+** The Emacs server now has socket-launching support.  This allows
+socket based activation, where an external process like systemd can
+invoke the Emacs server process upon a socket connection event and
+hand the socket over to Emacs.  Emacs uses this socket to service
+emacsclient commands.  This new functionality can be disabled with the
+configure option '--disable-libsystemd'.
 
 ** New configure option '--disable-build-details' attempts to build an
 Emacs that is more likely to be reproducible; that is, if you build
diff --git a/src/emacs.c b/src/emacs.c
index a51df09..a738bac 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -57,9 +57,9 @@ along with GNU Emacs.  If not, see 
<http://www.gnu.org/licenses/>.  */
 #endif
 
 #ifdef HAVE_LIBSYSTEMD
-#include <systemd/sd-daemon.h>
-#include <sys/socket.h>
-#endif /* HAVE_LIBSYSTEMD */
+# include <systemd/sd-daemon.h>
+# include <sys/socket.h>
+#endif
 
 #ifdef HAVE_WINDOW_SYSTEM
 #include TERM_HEADER
@@ -681,9 +681,6 @@ main (int argc, char **argv)
   char dname_arg2[80];
 #endif
   char *ch_to_dir = 0;
-#ifdef HAVE_LIBSYSTEMD
-  int systemd_socket;
-#endif
 
   /* If we use --chdir, this records the original directory.  */
   char *original_pwd = 0;
@@ -1008,16 +1005,17 @@ main (int argc, char **argv)
        }
 
 #ifdef HAVE_LIBSYSTEMD
-      /* Read the number of sockets passed through by systemd. */
-      systemd_socket = sd_listen_fds(1);
+      /* Read the number of sockets passed through by systemd.  */
+      int 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");
-
-      else if (systemd_socket == 1 &&
-               sd_is_socket (SD_LISTEN_FDS_START,
-                             AF_UNSPEC, SOCK_STREAM, 1) >= 0)
+        fprintf (stderr,
+                ("\n"
+                 "Warning: systemd passed more than one socket to Emacs.\n"
+                 "Try 'Accept=false' in the Emacs socket unit file.\n"));
+      else if (systemd_socket == 1
+              && (0 < sd_is_socket (SD_LISTEN_FDS_START,
+                                    AF_UNSPEC, SOCK_STREAM, 1)))
         set_external_socket_descriptor (SD_LISTEN_FDS_START);
 #endif /* HAVE_LIBSYSTEMD */
 
diff --git a/src/process.c b/src/process.c
index 2dfad66..a222a5b 100644
--- a/src/process.c
+++ b/src/process.c
@@ -267,8 +267,8 @@ static int max_process_desc;
 /* The largest descriptor currently in use for input; -1 if none.  */
 static int max_input_desc;
 
-/* The descriptor  of any sockets passed to Emacs; -1 if none. */
-static int external_sock_fd = -1;
+/* The descriptor of any socket passed to Emacs; -1 if none. */
+static int external_sock_fd;
 
 /* Indexed by descriptor, gives the process (if any) for that descriptor.  */
 static Lisp_Object chan_process[FD_SETSIZE];
@@ -3099,11 +3099,10 @@ connect_network_socket (Lisp_Object proc, Lisp_Object 
ip_addresses,
     {
       socket_to_use = external_sock_fd;
 
-      /* Ensure we don't consume the external socket twice. */
+      /* Ensure we don't consume the external socket twice.  */
       external_sock_fd = -1;
     }
 
-
   /* Do this in case we never enter the while-loop below.  */
   count1 = SPECPDL_INDEX ();
   s = -1;
@@ -3123,15 +3122,15 @@ connect_network_socket (Lisp_Object proc, Lisp_Object 
ip_addresses,
       sa = xmalloc (addrlen);
       conv_lisp_to_sockaddr (family, ip_address, sa, addrlen);
 
-      if (socket_to_use != -1)
-          s = socket_to_use;
-      else
-          s = socket (family, p->socktype | SOCK_CLOEXEC, p->ai_protocol);
-
+      s = socket_to_use;
       if (s < 0)
        {
-         xerrno = errno;
-         continue;
+         s = socket (family, p->socktype | SOCK_CLOEXEC, p->ai_protocol);
+         if (s < 0)
+           {
+             xerrno = errno;
+             continue;
+           }
        }
 
 #ifdef DATAGRAM_SOCKETS
@@ -3186,11 +3185,9 @@ connect_network_socket (Lisp_Object proc, Lisp_Object 
ip_addresses,
                  report_file_error ("Cannot set reuse option on server 
socket", Qnil);
              }
 
-          /* If we are passed a socket descriptor, it should be
-             already bound. */
-         if (socket_to_use == -1)
-           if (bind (s, sa, addrlen))
-             report_file_error ("Cannot bind server socket", Qnil);
+          /* If passed a socket descriptor, it should be already bound. */
+         if (socket_to_use < 0 && bind (s, sa, addrlen) != 0)
+           report_file_error ("Cannot bind server socket", Qnil);
 
 #ifdef HAVE_GETSOCKNAME
          if (p->port == 0)
@@ -7741,9 +7738,9 @@ catch_child_signal (void)
    `:use-external-socket' option.  The fd should have been checked to
    ensure it is a valid socket and is already bound.  */
 void
-set_external_socket_descriptor(int fd)
+set_external_socket_descriptor (int fd)
 {
-    external_sock_fd = fd;
+  external_sock_fd = fd;
 }
 
 
@@ -7775,7 +7772,7 @@ init_process_emacs (void)
   FD_ZERO (&non_keyboard_wait_mask);
   FD_ZERO (&non_process_wait_mask);
   FD_ZERO (&write_mask);
-  max_process_desc = max_input_desc = -1;
+  max_process_desc = max_input_desc = external_sock_fd = -1;
   memset (fd_callback_info, 0, sizeof (fd_callback_info));
 
   FD_ZERO (&connect_wait_mask);