Quoting Oren Laadan (orenl@xxxxxxxxxxx): > This patch adds support for checkpoint and restart of pseudo terminals > (PTYs). Since PTYs are shared (pointed to by file, and signal), they > are managed via objhash. > > PTYs are master/slave pairs; The code arranges for the master to > always be checkpointed first, followed by the slave. This is important > since during restart both ends are created when restoring the master. > > In this patch only UNIX98 style PTYs are supported. > > Currently only PTYs that are referenced by open files are handled. > Thus PTYs checkpoint starts with a file in tty_file_checkpoint(). It > will first checkpoint the master and slave PTYs via tty_checkpoint(), > and then complete the saving of the file descriptor. This means that > in the image file, the order of objects is: master-tty, slave-tty, > file-desc. > > During restart, to restore the master side, we open the /dev/ptmx > device and get a file handle. But at this point we don't know the > designated objref for this file, because the file is due later on in > the image stream. On the other hand, we can't just fput() the file > because it will close the PTY too. > > Instead, when we checkpoint the master PTY, we _reserve_ an objref > for the file (which won't be further used in checkpoint). Then at > restart, use it to insert the file to objhash. > > TODO: > > * Better sanitize input from checkpoint image on restore > * Check the locking when saving/restoring tty_struct state > * Echo position/buffer isn't saved (is it needed ?) > * Handle multiple devpts mounts (namespaces) > * Paths of ptmx and slaves are hard coded (/dev/ptmx, /dev/pts/...) > > Changelog[v1]: > - Adjust include/asm/checkpoint_hdr.h for s390 architecture > - Add NCC to kernel constants header (ckpt_hdr_const) > - [Serge Hallyn] fix calculation of canon_datalen > > Signed-off-by: Oren Laadan <orenl@xxxxxxxxxxxxxxx> First three patches can get Acked-by: Serge Hallyn <serue@xxxxxxxxxx> Tested-by: Serge Hallyn <serue@xxxxxxxxxx> _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
