diff options
Diffstat (limited to 'sys/kern/kern_shutdown.c')
| -rw-r--r-- | sys/kern/kern_shutdown.c | 133 |
1 files changed, 130 insertions, 3 deletions
diff --git a/sys/kern/kern_shutdown.c b/sys/kern/kern_shutdown.c index 5eba047..8139c8c 100644 --- a/sys/kern/kern_shutdown.c +++ b/sys/kern/kern_shutdown.c @@ -50,6 +50,7 @@ __FBSDID("$FreeBSD$"); #include <sys/conf.h> #include <sys/cons.h> #include <sys/eventhandler.h> +#include <sys/filedesc.h> #include <sys/jail.h> #include <sys/kdb.h> #include <sys/kernel.h> @@ -157,10 +158,16 @@ static struct dumperinfo dumper; /* our selected dumper */ static struct pcb dumppcb; /* Registers. */ lwpid_t dumptid; /* Thread ID. */ +static struct cdevsw reroot_cdevsw = { + .d_version = D_VERSION, + .d_name = "reroot", +}; + static void poweroff_wait(void *, int); static void shutdown_halt(void *junk, int howto); static void shutdown_panic(void *junk, int howto); static void shutdown_reset(void *junk, int howto); +static int kern_reroot(void); /* register various local shutdown events */ static void @@ -180,6 +187,26 @@ shutdown_conf(void *unused) SYSINIT(shutdown_conf, SI_SUB_INTRINSIC, SI_ORDER_ANY, shutdown_conf, NULL); /* + * The only reason this exists is to create the /dev/reroot/ directory, + * used by reroot code in init(8) as a mountpoint for tmpfs. + */ +static void +reroot_conf(void *unused) +{ + int error; + struct cdev *cdev; + + error = make_dev_p(MAKEDEV_CHECKNAME | MAKEDEV_WAITOK, &cdev, + &reroot_cdevsw, NULL, UID_ROOT, GID_WHEEL, 0600, "reroot/reroot"); + if (error != 0) { + printf("%s: failed to create device node, error %d", + __func__, error); + } +} + +SYSINIT(reroot_conf, SI_SUB_DEVFS, SI_ORDER_ANY, reroot_conf, NULL); + +/* * The system call that results in a reboot. */ /* ARGSUSED */ @@ -195,9 +222,13 @@ sys_reboot(struct thread *td, struct reboot_args *uap) if (error == 0) error = priv_check(td, PRIV_REBOOT); if (error == 0) { - mtx_lock(&Giant); - kern_reboot(uap->opt); - mtx_unlock(&Giant); + if (uap->opt & RB_REROOT) { + error = kern_reroot(); + } else { + mtx_lock(&Giant); + kern_reboot(uap->opt); + mtx_unlock(&Giant); + } } return (error); } @@ -462,6 +493,102 @@ kern_reboot(int howto) } /* + * The system call that results in changing the rootfs. + */ +static int +kern_reroot(void) +{ + struct vnode *oldrootvnode, *vp; + struct mount *mp, *devmp; + int error; + + if (curproc != initproc) + return (EPERM); + + /* + * Mark the filesystem containing currently-running executable + * (the temporary copy of init(8)) busy. + */ + vp = curproc->p_textvp; + error = vn_lock(vp, LK_SHARED); + if (error != 0) + return (error); + mp = vp->v_mount; + error = vfs_busy(mp, MBF_NOWAIT); + if (error != 0) { + vfs_ref(mp); + VOP_UNLOCK(vp, 0); + error = vfs_busy(mp, 0); + vn_lock(vp, LK_SHARED | LK_RETRY); + vfs_rel(mp); + if (error != 0) { + VOP_UNLOCK(vp, 0); + return (ENOENT); + } + if (vp->v_iflag & VI_DOOMED) { + VOP_UNLOCK(vp, 0); + vfs_unbusy(mp); + return (ENOENT); + } + } + VOP_UNLOCK(vp, 0); + + /* + * Remove the filesystem containing currently-running executable + * from the mount list, to prevent it from being unmounted + * by vfs_unmountall(), and to avoid confusing vfs_mountroot(). + * + * Also preserve /dev - forcibly unmounting it could cause driver + * reinitialization. + */ + + vfs_ref(rootdevmp); + devmp = rootdevmp; + rootdevmp = NULL; + + mtx_lock(&mountlist_mtx); + TAILQ_REMOVE(&mountlist, mp, mnt_list); + TAILQ_REMOVE(&mountlist, devmp, mnt_list); + mtx_unlock(&mountlist_mtx); + + oldrootvnode = rootvnode; + + /* + * Unmount everything except for the two filesystems preserved above. + */ + vfs_unmountall(); + + /* + * Add /dev back; vfs_mountroot() will move it into its new place. + */ + mtx_lock(&mountlist_mtx); + TAILQ_INSERT_HEAD(&mountlist, devmp, mnt_list); + mtx_unlock(&mountlist_mtx); + rootdevmp = devmp; + vfs_rel(rootdevmp); + + /* + * Mount the new rootfs. + */ + vfs_mountroot(); + + /* + * Update all references to the old rootvnode. + */ + mountcheckdirs(oldrootvnode, rootvnode); + + /* + * Add the temporary filesystem back and unbusy it. + */ + mtx_lock(&mountlist_mtx); + TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list); + mtx_unlock(&mountlist_mtx); + vfs_unbusy(mp); + + return (0); +} + +/* * If the shutdown was a clean halt, behave accordingly. */ static void |
