memfd is created by default with +x permissions set. This can be changed
by a process using fchmod() and expected to prevent using this fd for
exec(). Migrate the permissions.
Signed-off-by: Michał Mirosław <emmir@google.com>
This changes the license of all files in the images/ directory from
GPLv2 to the Expat license (so-called MIT).
According to git the files have been authored by:
Abhishek Dubey
Adrian Reber
Alexander Mikhalitsyn
Alice Frosi
Andrei Vagin (Andrew Vagin, Andrey Vagin)
Cyrill Gorcunov
Dengguangxing
Dmitry Safonov
Guoyun Sun
Kirill Tkhai
Kir Kolyshkin
Laurent Dufour
Michael Holzheu
Michał Cłapiński
Mike Rapoport
Nicolas Viennot
Nikita Spiridonov
Pavel Emelianov (Pavel Emelyanov)
Pavel Tikhomirov
Radostin Stoyanov
rbruno@gsd.inesc-id.pt
Sebastian Pipping
Stanislav Kinsburskiy
Tycho Andersen
Valeriy Vdovin
The Expat license (so-called MIT) can be found here:
https://opensource.org/licenses/MIT
According to that link the correct SPDX short identifier is 'MIT'.
https://spdx.org/licenses/MIT.html
Signed-off-by: Adrian Reber <areber@redhat.com>
Per-object image is acceptable if we expect to have 1-3 objects
per-container. If we expect to have more objects, it is better to save
them all into one image. There are a number of reasons for this:
* We need fewer system calls to read all objects from one image.
* It is faster to save or move one image.
Signed-off-by: Andrei Vagin <avagin@gmail.com>
See "man fcntl" for more information about seals.
memfd are the only files that can be sealed, currently. For this
reason, we dump the seal values in the MEMFD_INODE image.
Restoring seals must be done carefully as the seal F_SEAL_FUTURE_WRITE
prevents future write access. This means that any memory mapping with
write access must be restored before restoring the seals.
Signed-off-by: Nicolas Viennot <Nicolas.Viennot@twosigma.com>
See "man memfd_create" for more information of what memfd is.
This adds support for memfd open files, that are not not memory mapped.
* We add a new kind of file: MEMFD.
* We add two image types MEMFD_FILE, and MEMFD_INODE.
MEMFD_FILE contains usual file information (e.g., position).
MEMFD_INODE contains the memfd name, and a shmid identifier
referring to the content.
* We reuse the shmem facilities for dumping memfd content as it
would be easier to support incremental checkpoints in the future.
Signed-off-by: Nicolas Viennot <Nicolas.Viennot@twosigma.com>
