summaryrefslogtreecommitdiff
path: root/src/volatile-root
diff options
context:
space:
mode:
Diffstat (limited to 'src/volatile-root')
l---------src/volatile-root/Makefile1
-rw-r--r--src/volatile-root/volatile-root.c157
2 files changed, 158 insertions, 0 deletions
diff --git a/src/volatile-root/Makefile b/src/volatile-root/Makefile
new file mode 120000
index 0000000000..d0b0e8e008
--- /dev/null
+++ b/src/volatile-root/Makefile
@@ -0,0 +1 @@
+../Makefile \ No newline at end of file
diff --git a/src/volatile-root/volatile-root.c b/src/volatile-root/volatile-root.c
new file mode 100644
index 0000000000..3c0b6fa1de
--- /dev/null
+++ b/src/volatile-root/volatile-root.c
@@ -0,0 +1,157 @@
+/***
+ This file is part of systemd.
+
+ Copyright 2016 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/mount.h>
+
+#include "alloc-util.h"
+#include "fs-util.h"
+#include "mkdir.h"
+#include "mount-util.h"
+#include "stat-util.h"
+#include "volatile-util.h"
+#include "string-util.h"
+#include "path-util.h"
+
+static int make_volatile(const char *path) {
+ _cleanup_free_ char *old_usr = NULL;
+ int r;
+
+ r = path_is_mount_point(path, NULL, AT_SYMLINK_FOLLOW);
+ if (r < 0)
+ return log_error_errno(r, "Couldn't determine whether %s is a mount point: %m", path);
+ if (r == 0) {
+ log_error("%s is not a mount point.", path);
+ return -EINVAL;
+ }
+
+ r = path_is_temporary_fs(path);
+ if (r < 0)
+ return log_error_errno(r, "Couldn't determine whether %s is a temporary file system: %m", path);
+ if (r > 0) {
+ log_info("%s already is a temporary file system.", path);
+ return 0;
+ }
+
+ r = chase_symlinks("/usr", path, CHASE_PREFIX_ROOT, &old_usr);
+ if (r < 0)
+ return log_error_errno(r, "/usr not available in old root: %m");
+
+ r = mkdir_p("/run/systemd/volatile-sysroot", 0700);
+ if (r < 0)
+ return log_error_errno(r, "Couldn't generate volatile sysroot directory: %m");
+
+ r = mount_verbose(LOG_ERR, "tmpfs", "/run/systemd/volatile-sysroot", "tmpfs", MS_STRICTATIME, "mode=755");
+ if (r < 0)
+ goto finish_rmdir;
+
+ if (mkdir("/run/systemd/volatile-sysroot/usr", 0755) < 0) {
+ r = -errno;
+ goto finish_umount;
+ }
+
+ r = mount_verbose(LOG_ERR, old_usr, "/run/systemd/volatile-sysroot/usr", NULL, MS_BIND|MS_REC, NULL);
+ if (r < 0)
+ goto finish_umount;
+
+ r = bind_remount_recursive("/run/systemd/volatile-sysroot/usr", true, NULL);
+ if (r < 0)
+ goto finish_umount;
+
+ r = umount_recursive(path, 0);
+ if (r < 0) {
+ log_error_errno(r, "Failed to unmount %s: %m", path);
+ goto finish_umount;
+ }
+
+ if (mount(NULL, "/", NULL, MS_SLAVE|MS_REC, NULL) < 0)
+ log_warning_errno(errno, "Failed to remount %s MS_SLAVE|MS_REC: %m", path);
+
+ r = mount_verbose(LOG_ERR, "/run/systemd/volatile-sysroot", path, NULL, MS_MOVE, NULL);
+
+finish_umount:
+ (void) umount_recursive("/run/systemd/volatile-sysroot", 0);
+
+finish_rmdir:
+ (void) rmdir("/run/systemd/volatile-sysroot");
+
+ return r;
+}
+
+int main(int argc, char *argv[]) {
+ VolatileMode m = _VOLATILE_MODE_INVALID;
+ const char *path;
+ int r;
+
+ log_set_target(LOG_TARGET_AUTO);
+ log_parse_environment();
+ log_open();
+
+ if (argc > 3) {
+ log_error("Too many arguments. Expected directory and mode.");
+ r = -EINVAL;
+ goto finish;
+ }
+
+ r = query_volatile_mode(&m);
+ if (r < 0) {
+ log_error_errno(r, "Failed to determine volatile mode from kernel command line.");
+ goto finish;
+ }
+ if (r == 0 && argc >= 2) {
+ /* The kernel command line always wins. However if nothing was set there, the argument passed here wins instead. */
+ m = volatile_mode_from_string(argv[1]);
+ if (m < 0) {
+ log_error("Couldn't parse volatile mode: %s", argv[1]);
+ r = -EINVAL;
+ goto finish;
+ }
+ }
+
+ if (argc < 3)
+ path = "/sysroot";
+ else {
+ path = argv[2];
+
+ if (isempty(path)) {
+ log_error("Directory name cannot be empty.");
+ r = -EINVAL;
+ goto finish;
+ }
+ if (!path_is_absolute(path)) {
+ log_error("Directory must be specified as absolute path.");
+ r = -EINVAL;
+ goto finish;
+ }
+ if (path_equal(path, "/")) {
+ log_error("Directory cannot be the root directory.");
+ r = -EINVAL;
+ goto finish;
+ }
+ }
+
+ if (m != VOLATILE_YES) {
+ r = 0;
+ goto finish;
+ }
+
+ r = make_volatile(path);
+
+finish:
+ return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
+}