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Merge pull request #27435 from poettering/renew-reboot

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pid1: add a new method of rebooting: userspace only under the name "soft-reboot"
This commit is contained in:
Lennart Poettering
2023-06-02 23:27:45 +02:00
committed by GitHub
parent 2e04ba9de9 5596fd8ff7
commit 4d824ac0d3
44 changed files with 827 additions and 133 deletions
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src/shared/fstab-util.c
+1
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@@ -47,6 +47,7 @@ bool fstab_is_extrinsic(const char *mount, const char *opts) {
if (PATH_STARTSWITH_SET(mount,
"/run/initramfs", /* This should stay around from before we boot until after we shutdown */
"/run/nextroot", /* Similar (though might be updated from the host) */
"/proc", /* All of this is API VFS */
"/sys", /* … dito … */
"/dev")) /* … dito … */
src/shared/mount-setup.c
+3 -2
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@@ -376,8 +376,9 @@ static int relabel_cb(
return RECURSE_DIR_CONTINUE;
case RECURSE_DIR_ENTER:
/* /run/initramfs is static data and big, no need to dynamically relabel its contents at boot... */
if (path_equal(path, "/run/initramfs"))
/* /run/initramfs/ + /run/nextroot/ are static data and big, no need to dynamically relabel
* its contents at boot... */
if (PATH_STARTSWITH_SET(path, "/run/initramfs", "/run/nextroot"))
return RECURSE_DIR_SKIP_ENTRY;
_fallthrough_;
src/shared/mount-util.c
+18
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@@ -1099,6 +1099,24 @@ int make_mount_point(const char *path) {
return 1;
}
int fd_make_mount_point(int fd) {
int r;
assert(fd >= 0);
r = fd_is_mount_point(fd, NULL, 0);
if (r < 0)
return log_debug_errno(r, "Failed to determine whether file descriptor is a mount point: %m");
if (r > 0)
return 0;
r = mount_follow_verbose(LOG_DEBUG, FORMAT_PROC_FD_PATH(fd), FORMAT_PROC_FD_PATH(fd), NULL, MS_BIND|MS_REC, NULL);
if (r < 0)
return r;
return 1;
}
int make_userns(uid_t uid_shift, uid_t uid_range, uid_t owner, RemountIdmapping idmapping) {
_cleanup_close_ int userns_fd = -EBADF;
_cleanup_free_ char *line = NULL;
src/shared/mount-util.h
+1
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@@ -100,6 +100,7 @@ int bind_mount_in_namespace(pid_t target, const char *propagate_path, const char
int mount_image_in_namespace(pid_t target, const char *propagate_path, const char *incoming_path, const char *src, const char *dest, bool read_only, bool make_file_or_directory, const MountOptions *options, const ImagePolicy *image_policy);
int make_mount_point(const char *path);
int fd_make_mount_point(int fd);
typedef enum RemountIdmapping {
REMOUNT_IDMAPPING_NONE,
src/shared/switch-root.c
+55 -30
View File
@@ -10,6 +10,7 @@
#include "base-filesystem.h"
#include "chase.h"
#include "creds-util.h"
#include "fd-util.h"
#include "initrd-util.h"
#include "log.h"
@@ -27,14 +28,26 @@
int switch_root(const char *new_root,
const char *old_root_after, /* path below the new root, where to place the old root after the transition; may be NULL to unmount it */
unsigned long mount_flags) { /* MS_MOVE or MS_BIND used for /proc/, /dev/, /run/, /sys/ */
SwitchRootFlags flags) {
struct {
const char *path;
unsigned long mount_flags;
} transfer_table[] = {
{ "/dev", MS_BIND|MS_REC }, /* Recursive, because we want to save the original /dev/shm + /dev/pts and similar */
{ "/sys", MS_BIND|MS_REC }, /* Similar, we want to retain various API VFS, or the cgroupv1 /sys/fs/cgroup/ tree */
{ "/proc", MS_BIND|MS_REC }, /* Similar */
{ "/run", MS_BIND }, /* Stuff mounted below this we don't save, as it might have lost its relevance, i.e. credentials, removable media and such, we rather want that the new boot mounts this fresh */
{ SYSTEM_CREDENTIALS_DIRECTORY, MS_BIND }, /* Credentials passed into the system should survive */
{ ENCRYPTED_SYSTEM_CREDENTIALS_DIRECTORY, MS_BIND }, /* Similar */
{ "/run/host", MS_BIND|MS_REC }, /* Host supplied hierarchy should also survive */
};
_cleanup_close_ int old_root_fd = -EBADF, new_root_fd = -EBADF;
_cleanup_free_ char *resolved_old_root_after = NULL;
int r, istmp;
assert(new_root);
assert(IN_SET(mount_flags, MS_MOVE, MS_BIND));
/* Check if we shall remove the contents of the old root */
old_root_fd = open("/", O_DIRECTORY|O_CLOEXEC);
@@ -53,11 +66,19 @@ int switch_root(const char *new_root,
return 0;
}
istmp = fd_is_temporary_fs(old_root_fd);
if (istmp < 0)
return log_error_errno(istmp, "Failed to stat root directory: %m");
if (istmp > 0)
log_debug("Root directory is on tmpfs, will do cleanup later.");
/* Make the new root directory a mount point if it isn't */
r = fd_make_mount_point(new_root_fd);
if (r < 0)
return log_error_errno(r, "Failed to make new root directory a mount point: %m");
if (FLAGS_SET(flags, SWITCH_ROOT_DESTROY_OLD_ROOT)) {
istmp = fd_is_temporary_fs(old_root_fd);
if (istmp < 0)
return log_error_errno(istmp, "Failed to stat root directory: %m");
if (istmp > 0)
log_debug("Root directory is on tmpfs, will do cleanup later.");
} else
istmp = -1; /* don't know */
if (old_root_after) {
/* Determine where we shall place the old root after the transition */
@@ -73,7 +94,8 @@ int switch_root(const char *new_root,
* all while making them invisible/inaccessible in the file system tree for later code. That makes
* sync'ing them then difficult. Let's hence issue a manual sync() here, so that we at least can
* guarantee all file systems are an a good state before entering this state. */
sync();
if (!FLAGS_SET(flags, SWITCH_ROOT_DONT_SYNC))
sync();
/* Work-around for kernel design: the kernel refuses MS_MOVE if any file systems are mounted
* MS_SHARED. Hence remount them MS_PRIVATE here as a work-around.
@@ -82,32 +104,35 @@ int switch_root(const char *new_root,
if (mount(NULL, "/", NULL, MS_REC|MS_PRIVATE, NULL) < 0)
return log_error_errno(errno, "Failed to set \"/\" mount propagation to private: %m");
FOREACH_STRING(path, "/sys", "/dev", "/run", "/proc") {
_cleanup_free_ char *chased = NULL;
r = chase(path, new_root, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &chased, NULL);
if (r < 0)
return log_error_errno(r, "Failed to resolve %s/%s: %m", new_root, path);
if (r > 0) {
/* Already exists. Let's see if it is a mount point already. */
r = path_is_mount_point(chased, NULL, 0);
if (r < 0)
return log_error_errno(r, "Failed to determine whether %s is a mount point: %m", chased);
if (r > 0) /* If it is already mounted, then do nothing */
continue;
} else
/* Doesn't exist yet? */
(void) mkdir_p_label(chased, 0755);
if (mount(path, chased, NULL, mount_flags, NULL) < 0)
return log_error_errno(errno, "Failed to mount %s to %s: %m", path, chased);
}
/* Do not fail if base_filesystem_create() fails. Not all switch roots are like base_filesystem_create() wants
* them to look like. They might even boot, if they are RO and don't have the FS layout. Just ignore the error
* and switch_root() nevertheless. */
(void) base_filesystem_create_fd(new_root_fd, new_root, UID_INVALID, GID_INVALID);
FOREACH_ARRAY(transfer, transfer_table, ELEMENTSOF(transfer_table)) {
_cleanup_free_ char *chased = NULL;
if (access(transfer->path, F_OK) < 0) {
log_debug_errno(errno, "Path '%s' to move to target root directory, not found, ignoring: %m", transfer->path);
continue;
}
r = chase(transfer->path, new_root, CHASE_PREFIX_ROOT, &chased, NULL);
if (r < 0)
return log_error_errno(r, "Failed to resolve %s/%s: %m", new_root, transfer->path);
/* Let's see if it is a mount point already. */
r = path_is_mount_point(chased, NULL, 0);
if (r < 0)
return log_error_errno(r, "Failed to determine whether %s is a mount point: %m", chased);
if (r > 0) /* If it is already mounted, then do nothing */
continue;
r = mount_nofollow_verbose(LOG_ERR, transfer->path, chased, NULL, transfer->mount_flags, NULL);
if (r < 0)
return r;
}
if (fchdir(new_root_fd) < 0)
return log_error_errno(errno, "Failed to change directory to %s: %m", new_root);
@@ -144,7 +169,7 @@ int switch_root(const char *new_root,
return log_error_errno(errno, "Failed to change directory: %m");
}
if (istmp) {
if (istmp > 0) {
struct stat rb;
if (fstat(old_root_fd, &rb) < 0)
src/shared/switch-root.h
+6 -1
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@@ -3,4 +3,9 @@
#include <stdbool.h>
int switch_root(const char *new_root, const char *old_root_after, unsigned long mount_flags);
typedef enum SwitchRootFlags {
SWITCH_ROOT_DESTROY_OLD_ROOT = 1 << 0, /* rm -rf old root when switching – under the condition that it is backed by non-persistent tmpfs/ramfs/… */
SWITCH_ROOT_DONT_SYNC = 1 << 1, /* don't call sync() immediately before switching root */
} SwitchRootFlags;
int switch_root(const char *new_root, const char *old_root_after, SwitchRootFlags flags);