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authorLennart Poettering <lennart@poettering.net>2012-05-09 01:24:50 +0200
committerLennart Poettering <lennart@poettering.net>2012-05-09 01:24:50 +0200
commit664f88a7e653918942b858e3f387be2ebc9ebf03 (patch)
treeb40346c72702bf7a88ea409e74c11f4a53dc7d3e /src
parent14753f341937b75b244261f36807330456fa33a8 (diff)
manager: introduce SwitchRoot bus call for initrd/main transition
Diffstat (limited to 'src')
-rw-r--r--src/core/dbus-manager.c52
-rw-r--r--src/core/main.c130
-rw-r--r--src/core/manager.c3
-rw-r--r--src/core/manager.h4
4 files changed, 148 insertions, 41 deletions
diff --git a/src/core/dbus-manager.c b/src/core/dbus-manager.c
index bdc9192217..2e6bc3dfec 100644
--- a/src/core/dbus-manager.c
+++ b/src/core/dbus-manager.c
@@ -32,6 +32,7 @@
#include "install.h"
#include "watchdog.h"
#include "hwclock.h"
+#include "path-util.h"
#define BUS_MANAGER_INTERFACE_BEGIN \
" <interface name=\"org.freedesktop.systemd1.Manager\">\n"
@@ -126,6 +127,10 @@
" <method name=\"PowerOff\"/>\n" \
" <method name=\"Halt\"/>\n" \
" <method name=\"KExec\"/>\n" \
+ " <method name=\"SwitchRoot\">\n" \
+ " <arg name=\"new_root\" type=\"s\" direction=\"in\"/>\n" \
+ " <arg name=\"init\" type=\"s\" direction=\"in\"/>\n" \
+ " </method>\n" \
" <method name=\"SetEnvironment\">\n" \
" <arg name=\"names\" type=\"as\" direction=\"in\"/>\n" \
" </method>\n" \
@@ -1177,6 +1182,53 @@ static DBusHandlerResult bus_manager_message_handler(DBusConnection *connection,
m->exit_code = MANAGER_KEXEC;
+ } else if (dbus_message_is_method_call(message, "org.freedesktop.systemd1.Manager", "SwitchRoot")) {
+ const char *switch_root, *switch_root_init;
+ char *u, *v;
+
+ if (!dbus_message_get_args(
+ message,
+ &error,
+ DBUS_TYPE_STRING, &switch_root,
+ DBUS_TYPE_STRING, &switch_root_init,
+ DBUS_TYPE_INVALID))
+ return bus_send_error_reply(connection, message, &error, -EINVAL);
+
+ if (path_equal(switch_root, "/") || !is_path(switch_root))
+ return bus_send_error_reply(connection, message, NULL, -EINVAL);
+
+ if (!isempty(switch_root_init) && !is_path(switch_root_init))
+ return bus_send_error_reply(connection, message, NULL, -EINVAL);
+
+ if (m->running_as != MANAGER_SYSTEM) {
+ dbus_set_error(&error, BUS_ERROR_NOT_SUPPORTED, "Switching root is only supported for system managers.");
+ return bus_send_error_reply(connection, message, &error, -ENOTSUP);
+ }
+
+ u = strdup(switch_root);
+ if (!u)
+ goto oom;
+
+ if (!isempty(switch_root_init)) {
+ v = strdup(switch_root_init);
+ if (!v) {
+ free(u);
+ goto oom;
+ }
+ } else
+ v = NULL;
+
+ free(m->switch_root);
+ free(m->switch_root_init);
+ m->switch_root = u;
+ m->switch_root_init = v;
+
+ reply = dbus_message_new_method_return(message);
+ if (!reply)
+ goto oom;
+
+ m->exit_code = MANAGER_SWITCH_ROOT;
+
} else if (dbus_message_is_method_call(message, "org.freedesktop.systemd1.Manager", "SetEnvironment")) {
char **l = NULL, **e = NULL;
diff --git a/src/core/main.c b/src/core/main.c
index 58780990c8..d7ce8abdac 100644
--- a/src/core/main.c
+++ b/src/core/main.c
@@ -32,6 +32,7 @@
#include <sys/wait.h>
#include <fcntl.h>
#include <sys/prctl.h>
+#include <sys/mount.h>
#include "manager.h"
#include "log.h"
@@ -47,6 +48,7 @@
#include "def.h"
#include "virt.h"
#include "watchdog.h"
+#include "path-util.h"
#include "mount-setup.h"
#include "loopback-setup.h"
@@ -1165,6 +1167,36 @@ static void test_cgroups(void) {
sleep(10);
}
+static int do_switch_root(const char *switch_root) {
+ int r;
+
+ if (path_equal(switch_root, "/"))
+ return 0;
+
+ if (chdir(switch_root) < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ if (mount(switch_root, "/", NULL, MS_MOVE, NULL) < 0) {
+ r = -errno;
+ chdir("/");
+ goto fail;
+ }
+
+ if (chroot(".") < 0)
+ log_warning("Failed to change root, ignoring: %s", strerror(-r));
+
+ /* FIXME: remove old root */
+
+ return 0;
+
+fail:
+ log_error("Failed to switch root, ignoring: %s", strerror(-r));
+
+ return r;
+}
+
int main(int argc, char *argv[]) {
Manager *m = NULL;
int r, retval = EXIT_FAILURE;
@@ -1179,6 +1211,7 @@ int main(int argc, char *argv[]) {
int j;
bool loaded_policy = false;
bool arm_reboot_watchdog = false;
+ char *switch_root = NULL, *switch_root_init = NULL;
#ifdef HAVE_SYSV_COMPAT
if (getpid() != 1 && strstr(program_invocation_short_name, "init")) {
@@ -1549,6 +1582,7 @@ int main(int argc, char *argv[]) {
break;
case MANAGER_REEXECUTE:
+
if (prepare_reexecute(m, &serialization, &fds) < 0)
goto finish;
@@ -1556,6 +1590,20 @@ int main(int argc, char *argv[]) {
log_notice("Reexecuting.");
goto finish;
+ case MANAGER_SWITCH_ROOT:
+ /* Steal the switch root parameters */
+ switch_root = m->switch_root;
+ switch_root_init = m->switch_root_init;
+ m->switch_root = m->switch_root_init = NULL;
+
+ if (!switch_root_init)
+ if (prepare_reexecute(m, &serialization, &fds) < 0)
+ goto finish;
+
+ reexecute = true;
+ log_notice("Switching root.");
+ goto finish;
+
case MANAGER_REBOOT:
case MANAGER_POWEROFF:
case MANAGER_HALT:
@@ -1588,66 +1636,66 @@ finish:
free_join_controllers();
dbus_shutdown();
-
label_finish();
if (reexecute) {
- const char *args[15];
- unsigned i = 0;
- char sfd[16];
+ const char **args;
+ unsigned i;
- assert(serialization);
- assert(fds);
+ /* Close and disarm the watchdog, so that the new
+ * instance can reinitialize it, but doesn't get
+ * rebooted while we do that */
+ watchdog_close(true);
- args[i++] = SYSTEMD_BINARY_PATH;
+ if (switch_root)
+ do_switch_root(switch_root);
- args[i++] = "--log-level";
- args[i++] = log_level_to_string(log_get_max_level());
+ args = newa(const char*, MAX(5, argc+1));
- args[i++] = "--log-target";
- args[i++] = log_target_to_string(log_get_target());
+ if (!switch_root_init) {
+ char sfd[16];
- if (arg_running_as == MANAGER_SYSTEM)
- args[i++] = "--system";
- else
- args[i++] = "--user";
+ /* First try to spawn ourselves with the right
+ * path, and with full serialization. We do
+ * this only if the user didn't specify an
+ * explicit init to spawn. */
- if (arg_dump_core)
- args[i++] = "--dump-core";
+ assert(serialization);
+ assert(fds);
- if (arg_crash_shell)
- args[i++] = "--crash-shell";
+ snprintf(sfd, sizeof(sfd), "%i", fileno(serialization));
+ char_array_0(sfd);
- if (arg_confirm_spawn)
- args[i++] = "--confirm-spawn";
+ i = 0;
+ args[i++] = SYSTEMD_BINARY_PATH;
+ args[i++] = arg_running_as == MANAGER_SYSTEM ? "--system" : "--user";
+ args[i++] = "--deserialize";
+ args[i++] = sfd;
+ args[i++] = NULL;
- if (arg_show_status)
- args[i++] = "--show-status=1";
- else
- args[i++] = "--show-status=0";
+ assert(i <= ELEMENTSOF(args));
+ execv(args[0], (char* const*) args);
+ }
-#ifdef HAVE_SYSV_COMPAT
- if (arg_sysv_console)
- args[i++] = "--sysv-console=1";
- else
- args[i++] = "--sysv-console=0";
-#endif
+ /* Try the fallback, if there is any, without any
+ * serialization. We pass the original argv[] and
+ * envp[]. (Well, modulo the ordering changes due to
+ * getopt() in argv[], and some cleanups in envp[],
+ * but let's hope that doesn't matter.) */
- snprintf(sfd, sizeof(sfd), "%i", fileno(serialization));
- char_array_0(sfd);
+ if (serialization)
+ fclose(serialization);
- args[i++] = "--deserialize";
- args[i++] = sfd;
+ if (fds)
+ fdset_free(fds);
+ i = 0;
+ args[i++] = switch_root_init ? switch_root_init : "/sbin/init";
+ for (j = 1; j < argc; j++)
+ args[i++] = argv[j];
args[i++] = NULL;
assert(i <= ELEMENTSOF(args));
-
- /* Close and disarm the watchdog, so that the new
- * instance can reinitialize it, but doesn't get
- * rebooted while we do that */
- watchdog_close(true);
-
execv(args[0], (char* const*) args);
log_error("Failed to reexecute: %m");
diff --git a/src/core/manager.c b/src/core/manager.c
index c6baf22ae5..bd86f89d53 100644
--- a/src/core/manager.c
+++ b/src/core/manager.c
@@ -522,6 +522,9 @@ void manager_free(Manager *m) {
close_pipe(m->idle_pipe);
+ free(m->switch_root);
+ free(m->switch_root_init);
+
free(m);
}
diff --git a/src/core/manager.h b/src/core/manager.h
index 6d1f5d86c2..92dc75db55 100644
--- a/src/core/manager.h
+++ b/src/core/manager.h
@@ -45,6 +45,7 @@ typedef enum ManagerExitCode {
MANAGER_POWEROFF,
MANAGER_HALT,
MANAGER_KEXEC,
+ MANAGER_SWITCH_ROOT,
_MANAGER_EXIT_CODE_MAX,
_MANAGER_EXIT_CODE_INVALID = -1
} ManagerExitCode;
@@ -233,6 +234,9 @@ struct Manager {
/* Type=idle pipes */
int idle_pipe[2];
+
+ char *switch_root;
+ char *switch_root_init;
};
int manager_new(ManagerRunningAs running_as, Manager **m);