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git.ipfire.org Git - thirdparty/systemd.git/blob - src/volatile-root/volatile-root.c
1 /* SPDX-License-Identifier: LGPL-2.1+ */
3 This file is part of systemd.
5 Copyright 2016 Lennart Poettering
10 #include "alloc-util.h"
13 #include "mount-util.h"
14 #include "stat-util.h"
15 #include "volatile-util.h"
16 #include "string-util.h"
17 #include "path-util.h"
19 static int make_volatile(const char *path
) {
20 _cleanup_free_
char *old_usr
= NULL
;
23 r
= path_is_mount_point(path
, NULL
, AT_SYMLINK_FOLLOW
);
25 return log_error_errno(r
, "Couldn't determine whether %s is a mount point: %m", path
);
27 log_error("%s is not a mount point.", path
);
31 r
= path_is_temporary_fs(path
);
33 return log_error_errno(r
, "Couldn't determine whether %s is a temporary file system: %m", path
);
35 log_info("%s already is a temporary file system.", path
);
39 r
= chase_symlinks("/usr", path
, CHASE_PREFIX_ROOT
, &old_usr
);
41 return log_error_errno(r
, "/usr not available in old root: %m");
43 r
= mkdir_p("/run/systemd/volatile-sysroot", 0700);
45 return log_error_errno(r
, "Couldn't generate volatile sysroot directory: %m");
47 r
= mount_verbose(LOG_ERR
, "tmpfs", "/run/systemd/volatile-sysroot", "tmpfs", MS_STRICTATIME
, "mode=755");
51 if (mkdir("/run/systemd/volatile-sysroot/usr", 0755) < 0) {
56 r
= mount_verbose(LOG_ERR
, old_usr
, "/run/systemd/volatile-sysroot/usr", NULL
, MS_BIND
|MS_REC
, NULL
);
60 r
= bind_remount_recursive("/run/systemd/volatile-sysroot/usr", true, NULL
);
64 r
= umount_recursive(path
, 0);
66 log_error_errno(r
, "Failed to unmount %s: %m", path
);
70 if (mount(NULL
, "/", NULL
, MS_SLAVE
|MS_REC
, NULL
) < 0)
71 log_warning_errno(errno
, "Failed to remount %s MS_SLAVE|MS_REC: %m", path
);
73 r
= mount_verbose(LOG_ERR
, "/run/systemd/volatile-sysroot", path
, NULL
, MS_MOVE
, NULL
);
76 (void) umount_recursive("/run/systemd/volatile-sysroot", 0);
79 (void) rmdir("/run/systemd/volatile-sysroot");
84 int main(int argc
, char *argv
[]) {
85 VolatileMode m
= _VOLATILE_MODE_INVALID
;
89 log_set_target(LOG_TARGET_AUTO
);
90 log_parse_environment();
94 log_error("Too many arguments. Expected directory and mode.");
99 r
= query_volatile_mode(&m
);
101 log_error_errno(r
, "Failed to determine volatile mode from kernel command line.");
104 if (r
== 0 && argc
>= 2) {
105 /* The kernel command line always wins. However if nothing was set there, the argument passed here wins instead. */
106 m
= volatile_mode_from_string(argv
[1]);
108 log_error("Couldn't parse volatile mode: %s", argv
[1]);
120 log_error("Directory name cannot be empty.");
124 if (!path_is_absolute(path
)) {
125 log_error("Directory must be specified as absolute path.");
129 if (path_equal(path
, "/")) {
130 log_error("Directory cannot be the root directory.");
136 if (m
!= VOLATILE_YES
) {
141 r
= make_volatile(path
);
144 return r
< 0 ? EXIT_FAILURE
: EXIT_SUCCESS
;