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-rw-r--r--Makefile.am4
-rw-r--r--src/core/main.c98
-rw-r--r--src/core/switch-root.c125
-rw-r--r--src/core/switch-root.h27
4 files changed, 164 insertions, 90 deletions
diff --git a/Makefile.am b/Makefile.am
index 7d6d744ee9..e9ac82c049 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -789,7 +789,9 @@ libsystemd_core_la_SOURCES = \
src/core/special.h \
src/core/bus-errors.h \
src/core/build.h \
- src/core/sysfs-show.h
+ src/core/sysfs-show.h \
+ src/core/switch-root.h \
+ src/core/switch-root.c
nodist_libsystemd_core_la_SOURCES = \
src/core/load-fragment-gperf.c \
diff --git a/src/core/main.c b/src/core/main.c
index 4d09cb7174..22052220f9 100644
--- a/src/core/main.c
+++ b/src/core/main.c
@@ -49,6 +49,7 @@
#include "virt.h"
#include "watchdog.h"
#include "path-util.h"
+#include "switch-root.h"
#include "mount-setup.h"
#include "loopback-setup.h"
@@ -1173,90 +1174,6 @@ static void test_cgroups(void) {
sleep(10);
}
-static int do_switch_root(const char *switch_root) {
- int r=0;
- /* Don't try to unmount the old "/", there's no way to do it. */
- const char *umounts[] = { "/dev", "/proc", "/sys", "/run", NULL };
- int i;
- int cfd = -1;
- struct stat switch_root_stat, sb;
- bool remove_old_root;
-
- if (path_equal(switch_root, "/"))
- return 0;
-
- if (stat(switch_root, &switch_root_stat) != 0) {
- r = -errno;
- log_error("failed to stat directory %s", switch_root);
- goto fail;
- }
-
- remove_old_root = in_initrd();
-
- for (i = 0; umounts[i] != NULL; i++) {
- char newmount[PATH_MAX];
-
- snprintf(newmount, sizeof(newmount), "%s%s", switch_root, umounts[i]);
-
- if ((stat(newmount, &sb) != 0) || (sb.st_dev != switch_root_stat.st_dev)) {
- /* mount point seems to be mounted already or stat failed */
- umount2(umounts[i], MNT_DETACH);
- continue;
- }
-
- if (mount(umounts[i], newmount, NULL, MS_MOVE, NULL) < 0) {
- log_error("failed to mount moving %s to %s",
- umounts[i], newmount);
- log_error("forcing unmount of %s", umounts[i]);
- umount2(umounts[i], MNT_FORCE);
- }
- }
-
- if (chdir(switch_root)) {
- r = -errno;
- log_error("failed to change directory to %s", switch_root);
- goto fail;
- }
-
- if (remove_old_root)
- cfd = open("/", O_RDONLY);
-
- if (mount(switch_root, "/", NULL, MS_MOVE, NULL) < 0) {
- r = -errno;
- log_error("failed to mount moving %s to /", switch_root);
- goto fail;
- }
-
- if (chroot(".")) {
- r = -errno;
- log_error("failed to change root");
- goto fail;
- }
-
- if (cfd >= 0) {
- struct stat rb;
-
- if (fstat(cfd, &rb)) {
- log_error("failed to stat old root directory");
- goto fail;
- }
-
- rm_rf_children(cfd, false, false, &rb);
- close(cfd);
- cfd=-1;
- }
-
- return 0;
-
-fail:
- if (cfd >= 0)
- close(cfd);
-
- 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;
@@ -1271,7 +1188,7 @@ 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;
+ char *switch_root_dir = NULL, *switch_root_init = NULL;
#ifdef HAVE_SYSV_COMPAT
if (getpid() != 1 && strstr(program_invocation_short_name, "init")) {
@@ -1673,7 +1590,7 @@ int main(int argc, char *argv[]) {
case MANAGER_SWITCH_ROOT:
/* Steal the switch root parameters */
- switch_root = m->switch_root;
+ switch_root_dir = m->switch_root;
switch_root_init = m->switch_root_init;
m->switch_root = m->switch_root_init = NULL;
@@ -1728,8 +1645,11 @@ finish:
* rebooted while we do that */
watchdog_close(true);
- if (switch_root)
- do_switch_root(switch_root);
+ if (switch_root_dir) {
+ r = switch_root(switch_root_dir);
+ if (r < 0)
+ log_error("Failed to switch root, ignoring: %s", strerror(-r));
+ }
args_size = MAX(6, argc+1);
args = newa(const char*, args_size);
@@ -1750,7 +1670,7 @@ finish:
i = 0;
args[i++] = SYSTEMD_BINARY_PATH;
- if (switch_root)
+ if (switch_root_dir)
args[i++] = "--switchedroot";
args[i++] = arg_running_as == MANAGER_SYSTEM ? "--system" : "--user";
args[i++] = "--deserialize";
diff --git a/src/core/switch-root.c b/src/core/switch-root.c
new file mode 100644
index 0000000000..ed0a31e697
--- /dev/null
+++ b/src/core/switch-root.c
@@ -0,0 +1,125 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ This file is part of systemd.
+
+ Copyright 2012 Harald Hoyer, Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <sys/stat.h>
+#include <stdbool.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/mount.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include "util.h"
+#include "path-util.h"
+#include "switch-root.h"
+
+int switch_root(const char *new_root) {
+
+ /* Don't try to unmount/move the old "/", there's no way to do it. */
+ static const char move_mounts[] =
+ "/dev\0"
+ "/proc\0"
+ "/sys\0"
+ "/run\0";
+
+ int r, old_root_fd = -1;
+ struct stat new_root_stat;
+ bool old_root_remove;
+ const char *i;
+
+ if (path_equal(new_root, "/"))
+ return 0;
+
+ old_root_remove = in_initrd();
+
+ if (stat(new_root, &new_root_stat) < 0) {
+ r = -errno;
+ log_error("Failed to stat directory %s: %m", new_root);
+ goto fail;
+ }
+
+ NULSTR_FOREACH(i, move_mounts) {
+ char new_mount[PATH_MAX];
+ struct stat sb;
+
+ snprintf(new_mount, sizeof(new_mount), "%s%s", new_root, i);
+ char_array_0(new_mount);
+
+ if ((stat(new_mount, &sb) < 0) ||
+ sb.st_dev != new_root_stat.st_dev) {
+
+ /* Mount point seems to be mounted already or
+ * stat failed. Unmount the old mount
+ * point. */
+ if (umount2(i, MNT_DETACH) < 0)
+ log_warning("Failed to unmount %s: %m", i);
+ continue;
+ }
+
+ if (mount(i, new_mount, NULL, MS_MOVE, NULL) < 0) {
+ log_error("Failed to move mount %s to %s, forcing unmount: %m", i, new_mount);
+
+ if (umount2(i, MNT_FORCE) < 0)
+ log_warning("Failed to unmount %s: %m", i);
+ }
+ }
+
+ if (chdir(new_root) < 0) {
+ r = -errno;
+ log_error("Failed to change directory to %s: %m", new_root);
+ goto fail;
+ }
+
+ if (old_root_remove) {
+ old_root_fd = open("/", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_NOCTTY|O_DIRECTORY);
+ if (old_root_fd < 0)
+ log_warning("Failed to open root directory: %m");
+ }
+
+ if (mount(new_root, "/", NULL, MS_MOVE, NULL) < 0) {
+ r = -errno;
+ log_error("Failed to mount moving %s to /: %m", new_root);
+ goto fail;
+ }
+
+ if (chroot(".") < 0) {
+ r = -errno;
+ log_error("Failed to change root: %m");
+ goto fail;
+ }
+
+ if (old_root_fd >= 0) {
+ struct stat rb;
+
+ if (fstat(old_root_fd, &rb) < 0)
+ log_warning("Failed to stat old root directory, leaving: %m");
+ else
+ rm_rf_children(old_root_fd, false, false, &rb);
+ }
+
+ r = 0;
+
+fail:
+ if (old_root_fd >= 0)
+ close_nointr_nofail(old_root_fd);
+
+ return r;
+}
diff --git a/src/core/switch-root.h b/src/core/switch-root.h
new file mode 100644
index 0000000000..0c4cd1e403
--- /dev/null
+++ b/src/core/switch-root.h
@@ -0,0 +1,27 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#ifndef fooswitchroothfoo
+#define fooswitchroothfoo
+
+/***
+ This file is part of systemd.
+
+ Copyright 2012 Harald Hoyer, Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+int switch_root(const char *switch_root);
+
+#endif
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-17 18:59:38 +0000