From: Lennart Poettering Date: Tue, 8 May 2012 23:24:50 +0000 (+0200) Subject: manager: introduce SwitchRoot bus call for initrd/main transition X-Git-Tag: v183~135 X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=664f88a7e653918942b858e3f387be2ebc9ebf03 manager: introduce SwitchRoot bus call for initrd/main transition --- diff --git a/src/core/dbus-manager.c b/src/core/dbus-manager.c index bdc919221..2e6bc3dfe 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 \ " \n" @@ -126,6 +127,10 @@ " \n" \ " \n" \ " \n" \ + " \n" \ + " \n" \ + " \n" \ + " \n" \ " \n" \ " \n" \ " \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 58780990c..d7ce8abda 100644 --- a/src/core/main.c +++ b/src/core/main.c @@ -32,6 +32,7 @@ #include #include #include +#include #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 c6baf22ae..bd86f89d5 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 6d1f5d86c..92dc75db5 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);