Quoting Oren Laadan ([email protected]): > Add checkpoint/restart of controlling terminal: current->signal->tty. > This is only done for session leaders. > > If the session leader belongs to the ancestor pid-ns, then checkpoint > skips this tty; On restart, it will not be restored, and whatever tty > is in place from parent pid-ns (at restart) will be inherited. > > Signed-off-by: Oren Laadan <[email protected]>
Not exactly my area, but looks good Acked-by: Serge Hallyn <[email protected]> > --- > checkpoint/signal.c | 78 ++++++++++++++++++++++++++++++++++++++- > drivers/char/tty_io.c | 33 +++++++++++++---- > include/linux/checkpoint.h | 1 + > include/linux/checkpoint_hdr.h | 6 +++ > include/linux/tty.h | 5 +++ > 5 files changed, 114 insertions(+), 9 deletions(-) > > diff --git a/checkpoint/signal.c b/checkpoint/signal.c > index ad06783..178a97c 100644 > --- a/checkpoint/signal.c > +++ b/checkpoint/signal.c > @@ -315,11 +315,12 @@ static int checkpoint_signal(struct ckpt_ctx *ctx, > struct task_struct *t) > struct ckpt_hdr_signal *h; > struct signal_struct *signal; > struct sigpending shared_pending; > + struct tty_struct *tty = NULL; > struct rlimit *rlim; > struct timeval tval; > cputime_t cputime; > unsigned long flags; > - int i, ret; > + int i, ret = 0; > > h = ckpt_hdr_get_type(ctx, sizeof(*h), CKPT_HDR_SIGNAL); > if (!h) > @@ -398,9 +399,34 @@ static int checkpoint_signal(struct ckpt_ctx *ctx, > struct task_struct *t) > cputime_to_timeval(signal->it_prof_incr, &tval); > h->it_prof_incr = timeval_to_ns(&tval); > > + /* tty */ > + if (signal->leader) { > + h->tty_old_pgrp = ckpt_pid_nr(ctx, signal->tty_old_pgrp); > + tty = tty_kref_get(signal->tty); > + if (tty) { > + /* irq is already disabled */ > + spin_lock(&tty->ctrl_lock); > + h->tty_pgrp = ckpt_pid_nr(ctx, tty->pgrp); > + spin_unlock(&tty->ctrl_lock); > + tty_kref_put(tty); > + } > + } > + > unlock_task_sighand(t, &flags); > > - ret = ckpt_write_obj(ctx, &h->h); > + /* > + * If the session is in an ancestor namespace, skip this tty > + * and set tty_objref = 0. It will not be explicitly restored, > + * but rather inherited from parent pid-ns at restart time. > + */ > + if (tty && ckpt_pid_nr(ctx, tty->session) > 0) { > + h->tty_objref = checkpoint_obj(ctx, tty, CKPT_OBJ_TTY); > + if (h->tty_objref < 0) > + ret = h->tty_objref; > + } > + > + if (!ret) > + ret = ckpt_write_obj(ctx, &h->h); > if (!ret) > ret = checkpoint_sigpending(ctx, &shared_pending); > > @@ -471,8 +497,10 @@ static int restore_signal(struct ckpt_ctx *ctx) > struct ckpt_hdr_signal *h; > struct sigpending new_pending; > struct sigpending *pending; > + struct tty_struct *tty = NULL; > struct itimerval itimer; > struct rlimit rlim; > + struct pid *pgrp; > int i, ret; > > h = ckpt_read_obj_type(ctx, sizeof(*h), CKPT_HDR_SIGNAL); > @@ -492,6 +520,36 @@ static int restore_signal(struct ckpt_ctx *ctx) > if (ret < 0) > goto out; > > + /* tty - session */ > + if (h->tty_objref) { > + tty = ckpt_obj_fetch(ctx, h->tty_objref, CKPT_OBJ_TTY); > + if (IS_ERR(tty)) { > + ret = PTR_ERR(tty); > + goto out; > + } > + /* this will fail unless we're the session leader */ > + ret = tiocsctty(tty, 0); > + if (ret < 0) > + goto out; > + /* now restore the foreground group (job control) */ > + if (h->tty_pgrp) { > + ret = do_tiocspgrp(tty, tty_pair_get_tty(tty), > + h->tty_pgrp); > + if (ret < 0) > + goto out; > + } > + } else { > + /* > + * If tty_objref isn't set, we _keep_ whatever tty we > + * already have as a ctty. Why does this make sense ? > + * - If our session is "within" the restart context, > + * then that session has no controlling terminal. > + * - If out session is "outside" the restart context, > + * then we're like to keep whatever we inherit from > + * the parent pid-ns. > + */ > + } > + > /* > * Reset real/virt/prof itimer (in case they were set), to > * prevent unwanted signals after flushing current signals > @@ -503,7 +561,23 @@ static int restore_signal(struct ckpt_ctx *ctx) > do_setitimer(ITIMER_VIRTUAL, &itimer, NULL); > do_setitimer(ITIMER_PROF, &itimer, NULL); > > + /* tty - tty_old_pgrp */ > + if (h->tty_old_pgrp) { > + ret = -EINVAL; > + if (!current->signal->leader) > + goto out; > + rcu_read_lock(); > + pgrp = get_pid(_ckpt_find_pgrp(ctx, h->tty_old_pgrp)); > + rcu_read_unlock(); > + if (!pgrp) > + goto out; > + } > + > spin_lock_irq(¤t->sighand->siglock); > + /* tty - tty_old_pgrp */ > + put_pid(current->signal->tty_old_pgrp); > + current->signal->tty_old_pgrp = pgrp; > + /* pending signals */ > pending = ¤t->signal->shared_pending; > flush_sigqueue(pending); > pending->signal = new_pending.signal; > diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c > index b8f8d79..0206300 100644 > --- a/drivers/char/tty_io.c > +++ b/drivers/char/tty_io.c > @@ -2132,7 +2132,7 @@ static int fionbio(struct file *file, int __user *p) > * Takes ->siglock() when updating signal->tty > */ > > -static int tiocsctty(struct tty_struct *tty, int arg) > +int tiocsctty(struct tty_struct *tty, int arg) > { > int ret = 0; > if (current->signal->leader && (task_session(current) == tty->session)) > @@ -2221,10 +2221,10 @@ static int tiocgpgrp(struct tty_struct *tty, struct > tty_struct *real_tty, pid_t > } > > /** > - * tiocspgrp - attempt to set process group > + * do_tiocspgrp - attempt to set process group > * @tty: tty passed by user > * @real_tty: tty side device matching tty passed by user > - * @p: pid pointer > + * @pid: pgrp_nr > * > * Set the process group of the tty to the session passed. Only > * permitted where the tty session is our session. > @@ -2232,10 +2232,10 @@ static int tiocgpgrp(struct tty_struct *tty, struct > tty_struct *real_tty, pid_t > * Locking: RCU, ctrl lock > */ > > -static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, > pid_t __user *p) > +int do_tiocspgrp(struct tty_struct *tty, > + struct tty_struct *real_tty, pid_t pgrp_nr) > { > struct pid *pgrp; > - pid_t pgrp_nr; > int retval = tty_check_change(real_tty); > unsigned long flags; > > @@ -2247,8 +2247,6 @@ static int tiocspgrp(struct tty_struct *tty, struct > tty_struct *real_tty, pid_t > (current->signal->tty != real_tty) || > (real_tty->session != task_session(current))) > return -ENOTTY; > - if (get_user(pgrp_nr, p)) > - return -EFAULT; > if (pgrp_nr < 0) > return -EINVAL; > rcu_read_lock(); > @@ -2270,6 +2268,27 @@ out_unlock: > } > > /** > + * tiocspgrp - attempt to set process group > + * @tty: tty passed by user > + * @real_tty: tty side device matching tty passed by user > + * @p: pid pointer > + * > + * Set the process group of the tty to the session passed. Only > + * permitted where the tty session is our session. > + * > + * Locking: RCU, ctrl lock > + */ > + > +static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, > pid_t __user *p) > +{ > + pid_t pgrp_nr; > + > + if (get_user(pgrp_nr, p)) > + return -EFAULT; > + return do_tiocspgrp(tty, real_tty, pgrp_nr); > +} > + > +/** > * tiocgsid - get session id > * @tty: tty passed by user > * @real_tty: tty side of the tty pased by the user if a pty else the tty > diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h > index 628d6f6..434c6b1 100644 > --- a/include/linux/checkpoint.h > +++ b/include/linux/checkpoint.h > @@ -87,6 +87,7 @@ extern char *ckpt_fill_fname(struct path *path, struct path > *root, > > /* pids */ > extern pid_t ckpt_pid_nr(struct ckpt_ctx *ctx, struct pid *pid); > +extern struct pid *_ckpt_find_pgrp(struct ckpt_ctx *ctx, pid_t pgid); > > /* socket functions */ > extern int ckpt_sock_getnames(struct ckpt_ctx *ctx, > diff --git a/include/linux/checkpoint_hdr.h b/include/linux/checkpoint_hdr.h > index c9ded68..398d5f7 100644 > --- a/include/linux/checkpoint_hdr.h > +++ b/include/linux/checkpoint_hdr.h > @@ -555,13 +555,19 @@ struct ckpt_rlimit { > > struct ckpt_hdr_signal { > struct ckpt_hdr h; > + /* rlimit */ > struct ckpt_rlimit rlim[CKPT_RLIM_NLIMITS]; > + /* itimer */ > __u64 it_real_value; > __u64 it_real_incr; > __u64 it_virt_value; > __u64 it_virt_incr; > __u64 it_prof_value; > __u64 it_prof_incr; > + /* tty */ > + __s32 tty_objref; > + __s32 tty_pgrp; > + __s32 tty_old_pgrp; > } __attribute__((aligned(8))); > > struct ckpt_hdr_signal_task { > diff --git a/include/linux/tty.h b/include/linux/tty.h > index fd77894..ee49d97 100644 > --- a/include/linux/tty.h > +++ b/include/linux/tty.h > @@ -467,6 +467,11 @@ extern void tty_ldisc_begin(void); > /* This last one is just for the tty layer internals and shouldn't be used > elsewhere */ > extern void tty_ldisc_enable(struct tty_struct *tty); > > +/* These are for checkpoint/restart */ > +extern int tiocsctty(struct tty_struct *tty, int arg); > +extern int do_tiocspgrp(struct tty_struct *tty, > + struct tty_struct *real_tty, pid_t pgrp_nr); > + > #ifdef CONFIG_CHECKPOINT > struct ckpt_ctx; > struct ckpt_hdr_file; > -- > 1.6.0.4 _______________________________________________ Containers mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
