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manager: introduce SwitchRoot bus call for initrd/main transition

This commit is contained in:
Lennart Poettering 2012-05-09 01:24:50 +02:00
parent 14753f3419
commit 664f88a7e6
4 changed files with 158 additions and 51 deletions
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52
src/core/dbus-manager.c
View File

@ -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;

150
src/core/main.c
View File

@ -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];
assert(serialization);
assert(fds);
args[i++] = SYSTEMD_BINARY_PATH;
args[i++] = "--log-level";
args[i++] = log_level_to_string(log_get_max_level());
args[i++] = "--log-target";
args[i++] = log_target_to_string(log_get_target());
if (arg_running_as == MANAGER_SYSTEM)
args[i++] = "--system";
else
args[i++] = "--user";
if (arg_dump_core)
args[i++] = "--dump-core";
if (arg_crash_shell)
args[i++] = "--crash-shell";
if (arg_confirm_spawn)
args[i++] = "--confirm-spawn";
if (arg_show_status)
args[i++] = "--show-status=1";
else
args[i++] = "--show-status=0";
#ifdef HAVE_SYSV_COMPAT
if (arg_sysv_console)
args[i++] = "--sysv-console=1";
else
args[i++] = "--sysv-console=0";
#endif
snprintf(sfd, sizeof(sfd), "%i", fileno(serialization));
char_array_0(sfd);
args[i++] = "--deserialize";
args[i++] = sfd;
args[i++] = NULL;
assert(i <= ELEMENTSOF(args));
const char **args;
unsigned i;
/* 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);
if (switch_root)
do_switch_root(switch_root);
args = newa(const char*, MAX(5, argc+1));
if (!switch_root_init) {
char sfd[16];
/* 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. */
assert(serialization);
assert(fds);
snprintf(sfd, sizeof(sfd), "%i", fileno(serialization));
char_array_0(sfd);
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;
assert(i <= ELEMENTSOF(args));
execv(args[0], (char* const*) args);
}
/* 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.) */
if (serialization)
fclose(serialization);
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));
execv(args[0], (char* const*) args);
log_error("Failed to reexecute: %m");

3
src/core/manager.c
View File

@ -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);
}

4
src/core/manager.h
View File

@ -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);