Currently it can only work with stream sockets, which have no skbs in queues
(listening or established -- both work OK).
The cpt part uses the sock_diag engine that was merged to Dave recently to
collect sockets. Then it dumps sockets by checking the filesystem ID of a
failed-to-open through /proc/pid/fd descriptors (sockets do not allow for
such tricks with opens through proc) against SOCKFS_TYPE.
The rst part is more tricky. Listen sockets are just restored, this is simple.
Connected sockets are restored like this:
1. One end establishes a listening anon socket at the desired descriptor;
2. The other end just creates a socket at the desired descriptor;
3. All sockets, that are to be connect()-ed call connect. Unix sockets
do not block connect() till the accept() time and thus we continue with...
4. ... all listening sockets call accept() and ... dup2 the new fd into the
accepting end.
There's a problem with this approach -- socket names are not preserved, but
looking into our OpenVZ implementation I think this is OK for existing apps.
What should be done next is:
1. Need to merge the file IDs patches in our tree and make Andrey to
support files sharing. This will solve the
sk = socket();
fork();
case. Currently it simply doesn't work :(
2. Need to add support for DGRAM sockets -- I wrote comment how to do it
in the can_dump_unix_sk()
3. Need to add support for in-flight connections
4. Implement support for UDP sockets (quite simple)
5. Implement support for listening TCP sockets (also not very complex)
6. Implement support for connected TCP scokets (hard one, Tejun's patches are not
very good for this from my POV)
Cyrill, plz, apply this patch and put the above descriptions onto wiki docs (do we
have the plans page yet?).
Andrey, plz, take care of unix sockets tests in zdtm. Most likely it won't work till
you do the shared files support for sockets.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
When opening an fd at a position where the current image fd sits
the latter one should be moved.
Introduce a helper for this.
Signed-off-by; Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Nobody cares the returned fd, so just make it 0/-1 and clean up the callers.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Kernel has a new format for process children
(ie /proc/<pid>/task/<tid>/children) so adopt
crtools for it.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Parsing children will require to know the number
of threads found so in a sake of consistency pass
single struct pstree_item here as well.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
The kernel patches are carried in a separate
repo anyway, so a second place for patches
might be confusing.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
This as well forces to move ptrace
definitions into ptrace.h, otherwise
freshly fetched kernel headers become
conflict with existing ptrace constants.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Regardless that we link all things in one executable
better declare them so from the very beggining.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Instead of keeping all unrelated to
C/R procedure helpers in util.c move
logging related helpers to log.c.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
This as well implies we change paths to PATH_MAX size.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelianov <xemul@parallels.com>
We have a mess in our return codes:
some functions return negative values,
while others -- positive.
Sanitize the return codes and make error
condition to return negative values.
Reported-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Otherwise it may begin to restore a parent objects...
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
For this reason a function may return success in case of error.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
1. pipe() returns two descriptors with numbers (r: x, w: y).
We may want to restore it as (r: y, w: x).
2. Close a extra end, before try to restore a target end.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
