[PATCH v6 00/21] tools: enable xenstore-stubdom to use 9pfs

[Juergen Gross <jgross@xxxxxxxx>]

This series is adding 9pfs support to Xenstore-stubdom, enabling it
to do logging to a dom0 directory.

This is a prerequisite for the final goal to add live update support
to Xenstore-stubdom, as it enables the stubdom to store its state in
a dom0 file.

The 9pfs backend is a new daemon written from scratch. Using a
dedicated 9pfs daemon has several advantages:

- it is using much less resources than a full blown qemu process
- it can serve multiple guests (the idea is to use it for other
  infrastructure domains, like qemu-stubdom or driver domains, too)
- it is designed to support several security enhancements, like
  limiting the number of files for a guest, or limiting the allocated
  file system space
- it doesn't support file links (neither hard nor soft links) or
  referencing parent directories via "..", minimizing the risk that
  a guest can "escape" from its home directory

Note that for now the daemon only contains the minimal needed
functionality to do logging from Xenstore-stubdom. I didn't want to
add all the 9pfs commands and security add-ons in the beginning, in
order to avoid needless efforts in case the idea of the daemon is
being rejected.

Please note that the pending patch for updating the Mini-OS commit
in Config.mk needs to be applied for patch "stubdom: extend xenstore
stubdom configs" and the following ones.

Changes in V6:
- patch 1 of V5 has been applied
- rebase
- addressed comments

Changes in V5:
- 10 patches have been applied already
- rename source directory to tools/9pfsd
- addressed comments

Changes in V4:
- patch 2 of V3 was applied
- added support of reading directories
- addressed review comments

Changes in V3:
- new patches 1, 23-25
- addressed review comments

Changes in V2:
- support of multiple rings per device
- xenlogd->xen-9pfsd rename
- addressed review comments
- fixed some bugs

Juergen Gross (21):
  tools: add a new xen 9pfs daemon
  tools/xen-9pfsd: connect to frontend
  tools/xen-9pfsd: add transport layer
  tools/xen-9pfsd: add 9pfs response generation support
  tools/xen-9pfsd: add 9pfs version request support
  tools/xen-9pfsd: add 9pfs attach request support
  tools/xen-9pfsd: add 9pfs walk request support
  tools/xen-9pfsd: add 9pfs open request support
  tools/xen-9pfsd: add 9pfs clunk request support
  tools/xen-9pfsd: add 9pfs create request support
  tools/xen-9pfsd: add 9pfs stat request support
  tools/xen-9pfsd: add 9pfs write request support
  tools/xen-9pfsd: add 9pfs read request support
  tools/libs/light: add backend type for 9pfs PV devices
  tools/xl: support new 9pfs backend xen_9pfsd
  stubdom: extend xenstore stubdom configs
  tools: add 9pfs device to xenstore-stubdom
  tools/xenstored: mount 9pfs device in stubdom
  tools/xenstored: add helpers for filename handling
  tools/xenstored: support complete log capabilities in stubdom
  tools/xenstored: have a single do_control_memreport()

 docs/man/xl.cfg.5.pod.in                      |   36 +-
 stubdom/xenstore-minios.cfg                   |    2 +-
 stubdom/xenstorepvh-minios.cfg                |    2 +-
 tools/9pfsd/.gitignore                        |    1 +
 tools/9pfsd/Makefile                          |   38 +
 tools/9pfsd/io.c                              | 1513 +++++++++++++++++
 tools/9pfsd/xen-9pfsd.c                       |  800 +++++++++
 tools/9pfsd/xen-9pfsd.h                       |   99 ++
 tools/Makefile                                |    1 +
 tools/golang/xenlight/helpers.gen.go          |   10 +
 tools/golang/xenlight/types.gen.go            |   12 +
 tools/helpers/init-xenstore-domain.c          |    7 +
 .../Linux/init.d/sysconfig.xencommons.in      |    1 -
 tools/hotplug/Linux/launch-xenstore.in        |    1 +
 tools/include/libxl.h                         |   22 +
 tools/libs/light/libxl_9pfs.c                 |  191 ++-
 tools/libs/light/libxl_create.c               |    4 +-
 tools/libs/light/libxl_dm.c                   |    2 +-
 tools/libs/light/libxl_types.idl              |   11 +
 tools/libs/light/libxl_types_internal.idl     |    1 +
 tools/xenstored/control.c                     |   29 +-
 tools/xenstored/core.c                        |   15 +-
 tools/xenstored/core.h                        |   11 +-
 tools/xenstored/domain.c                      |    2 +
 tools/xenstored/lu_daemon.c                   |    4 +-
 tools/xenstored/minios.c                      |   62 +
 tools/xenstored/posix.c                       |    8 +-
 tools/xl/xl_parse.c                           |   23 +-
 28 files changed, 2866 insertions(+), 42 deletions(-)
 create mode 100644 tools/9pfsd/.gitignore
 create mode 100644 tools/9pfsd/Makefile
 create mode 100644 tools/9pfsd/io.c
 create mode 100644 tools/9pfsd/xen-9pfsd.c
 create mode 100644 tools/9pfsd/xen-9pfsd.h

-- 
2.35.3