Ensure kdbus isn't used (systemd#3501)

Delete the dbus1 generator and some critical wiring. This prevents
kdbus from being loaded or detected. As such, it will never be used,
even if the user still has a useful kdbus module loaded on their system.

Sort of fixes systemd#3480. Not really, but it's better than the current state.

Makefile.am

@@ -2902,29 +2902,9 @@ systemd_gpt_auto_generator_CFLAGS = \
 endif
 
 # ------------------------------------------------------------------------------
-systemgenerator_PROGRAMS +=  \
-	systemd-dbus1-generator
-
-systemd_dbus1_generator_SOURCES = \
-	src/dbus1-generator/dbus1-generator.c
-
-systemd_dbus1_generator_LDADD = \
-	libshared.la
-
-dbus1-generator-install-hook:
-	$(AM_V_at)$(MKDIR_P) $(DESTDIR)$(usergeneratordir)
-	$(AM_V_RM)rm -f $(DESTDIR)$(usergeneratordir)/systemd-dbus1-generator
-	$(AM_V_LN)$(LN_S) --relative -f $(DESTDIR)$(systemgeneratordir)/systemd-dbus1-generator $(DESTDIR)$(usergeneratordir)/systemd-dbus1-generator
-
-dbus1-generator-uninstall-hook:
-	rm -f $(DESTDIR)$(usergeneratordir)/systemd-dbus1-generator
-
 dist_xinitrc_SCRIPTS = \
 	xorg/50-systemd-user.sh
 
-INSTALL_EXEC_HOOKS += dbus1-generator-install-hook
-UNINSTALL_EXEC_HOOKS += dbus1-generator-uninstall-hook
-
 # ------------------------------------------------------------------------------
 systemd_sysv_generator_SOURCES = \
 	src/sysv-generator/sysv-generator.c

autogen.sh

@@ -55,26 +55,26 @@ fi
 cd $oldpwd
 
 if [ "x$1" = "xc" ]; then
-        $topdir/configure CFLAGS='-g -O0 -ftrapv' --enable-kdbus $args
+        $topdir/configure CFLAGS='-g -O0 -ftrapv' $args
         make clean
 elif [ "x$1" = "xg" ]; then
-        $topdir/configure CFLAGS='-g -Og -ftrapv' --enable-kdbus $args
+        $topdir/configure CFLAGS='-g -Og -ftrapv' $args
         make clean
 elif [ "x$1" = "xa" ]; then
-        $topdir/configure CFLAGS='-g -O0 -Wsuggest-attribute=pure -Wsuggest-attribute=const -ftrapv' --enable-kdbus $args
+        $topdir/configure CFLAGS='-g -O0 -Wsuggest-attribute=pure -Wsuggest-attribute=const -ftrapv' $args
         make clean
 elif [ "x$1" = "xl" ]; then
-        $topdir/configure CC=clang CFLAGS='-g -O0 -ftrapv' --enable-kdbus $args
+        $topdir/configure CC=clang CFLAGS='-g -O0 -ftrapv' $args
         make clean
 elif [ "x$1" = "xs" ]; then
-        scan-build $topdir/configure CFLAGS='-std=gnu99 -g -O0 -ftrapv' --enable-kdbus $args
+        scan-build $topdir/configure CFLAGS='-std=gnu99 -g -O0 -ftrapv' $args
         scan-build make
 else
         echo
         echo "----------------------------------------------------------------"
         echo "Initialized build system. For a common configuration please run:"
         echo "----------------------------------------------------------------"
         echo
-        echo "$topdir/configure CFLAGS='-g -O0 -ftrapv' --enable-kdbus $args"
+        echo "$topdir/configure CFLAGS='-g -O0 -ftrapv' $args"
         echo
 fi

configure.ac

@@ -1279,16 +1279,6 @@ AC_ARG_WITH(tpm-pcrindex,
 
 AC_DEFINE_UNQUOTED(SD_TPM_PCR, [$SD_TPM_PCR], [TPM PCR register number to use])
 
-# ------------------------------------------------------------------------------
-have_kdbus=no
-AC_ARG_ENABLE(kdbus, AS_HELP_STRING([--disable-kdbus], [do not connect to kdbus by default]))
-if test "x$enable_kdbus" != "xno"; then
-        AC_DEFINE(ENABLE_KDBUS, 1, [Define if kdbus is to be connected to by default])
-        have_kdbus=yes
-        M4_DEFINES="$M4_DEFINES -DENABLE_KDBUS"
-fi
-AM_CONDITIONAL(ENABLE_KDBUS, [test "$have_kdbus" = "yes"])
-
 # ------------------------------------------------------------------------------
 AC_ARG_WITH(rc-local-script-path-start,
         AS_HELP_STRING([--with-rc-local-script-path-start=PATH],

src/core/busname.c

@@ -998,12 +998,7 @@ static int busname_get_timeout(Unit *u, usec_t *timeout) {
 }
 
 static bool busname_supported(void) {
-        static int supported = -1;
-
-        if (supported < 0)
-                supported = is_kdbus_available();
-
-        return supported;
+        return false;
 }
 
 static int busname_control_pid(Unit *u) {

src/core/kmod-setup.c

@@ -64,9 +64,6 @@ int kmod_setup(void) {
                 /* this should never be a module */
                 { "unix",      "/proc/net/unix",            true,   true,    NULL      },
 
-                /* IPC is needed before we bring up any other services */
-                { "kdbus",     "/sys/fs/kdbus",             false,  false,   is_kdbus_wanted },
-
 #ifdef HAVE_LIBIPTC
                 /* netfilter is needed by networkd, nspawn among others, and cannot be autoloaded */
                 { "ip_tables", "/proc/net/ip_tables_names", false,  false,   NULL      },

src/core/manager.c

@@ -814,28 +814,6 @@ static int manager_setup_cgroups_agent(Manager *m) {
         return 0;
 }
 
-static int manager_setup_kdbus(Manager *m) {
-        _cleanup_free_ char *p = NULL;
-
-        assert(m);
-
-        if (m->test_run || m->kdbus_fd >= 0)
-                return 0;
-        if (!is_kdbus_available())
-                return -ESOCKTNOSUPPORT;
-
-        m->kdbus_fd = bus_kernel_create_bus(
-                        MANAGER_IS_SYSTEM(m) ? "system" : "user",
-                        MANAGER_IS_SYSTEM(m), &p);
-
-        if (m->kdbus_fd < 0)
-                return log_debug_errno(m->kdbus_fd, "Failed to set up kdbus: %m");
-
-        log_debug("Successfully set up kdbus on %s", p);
-
-        return 0;
-}
-
 static int manager_connect_bus(Manager *m, bool reexecuting) {
         bool try_bus_connect;
 
@@ -1244,7 +1222,6 @@ int manager_startup(Manager *m, FILE *serialization, FDSet *fds) {
 
         /* We might have deserialized the kdbus control fd, but if we
          * didn't, then let's create the bus now. */
-        manager_setup_kdbus(m);
         manager_connect_bus(m, !!serialization);
         bus_track_coldplug(m, &m->subscribed, &m->deserialized_subscribed);
 

src/core/mount-setup.c

@@ -108,8 +108,6 @@ static const MountPoint mount_table[] = {
         { "efivarfs",    "/sys/firmware/efi/efivars", "efivarfs",   NULL,                      MS_NOSUID|MS_NOEXEC|MS_NODEV,
           is_efi_boot,   MNT_NONE                   },
 #endif
-        { "kdbusfs",    "/sys/fs/kdbus",             "kdbusfs",    NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
-          is_kdbus_wanted,       MNT_IN_CONTAINER },
 };
 
 /* These are API file systems that might be mounted by other software,

src/core/service.c

@@ -574,20 +574,9 @@ static int service_setup_bus_name(Service *s) {
         if (!s->bus_name)
                 return 0;
 
-        if (is_kdbus_available()) {
-                const char *n;
-
-                n = strjoina(s->bus_name, ".busname");
-                r = unit_add_dependency_by_name(UNIT(s), UNIT_AFTER, n, NULL, true);
-                if (r < 0)
-                        return log_unit_error_errno(UNIT(s), r, "Failed to add dependency to .busname unit: %m");
-
-        } else {
-                /* If kdbus is not available, we know the dbus socket is required, hence pull it in, and require it */
-                r = unit_add_dependency_by_name(UNIT(s), UNIT_REQUIRES, SPECIAL_DBUS_SOCKET, NULL, true);
-                if (r < 0)
-                        return log_unit_error_errno(UNIT(s), r, "Failed to add dependency on " SPECIAL_DBUS_SOCKET ": %m");
-        }
+        r = unit_add_dependency_by_name(UNIT(s), UNIT_REQUIRES, SPECIAL_DBUS_SOCKET, NULL, true);
+        if (r < 0)
+                return log_unit_error_errno(UNIT(s), r, "Failed to add dependency on " SPECIAL_DBUS_SOCKET ": %m");
 
         /* Regardless if kdbus is used or not, we always want to be ordered against dbus.socket if both are in the transaction. */
         r = unit_add_dependency_by_name(UNIT(s), UNIT_AFTER, SPECIAL_DBUS_SOCKET, NULL, true);