This patch was designed to be generic and thus usable for all kinds of
sockets. Not sure, thah this goal has been reached, but at least I tried.
Key ideas:
1) On-stack structure for collecting sockets queues and then passing them to
parasite code.
2) Singly linked list is used for collecting structures, representing sockets
of any kind (!) with queues.
Based on xemul@ patches.
Signed-off-by: Stanislav Kinsbursky <skinsbursky@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
This patch adds sockets queue dump functionality. Key ideas
1) sockets info is passed as plain array in parasite args.
2) new socket option SO_PEEK_OFF with MSG_PEEK is used to read the get the
queue's packets.
3) Buffer for packet will be allocated for each socket separately and with
size of socket sending buffer. For stream sockets is means, that it's queue
will be dumped in chunks of this size.
Note: loop around sys_msgrcv() is required for DGRAM sockets - sys_msgrcv()
with MSG_PEEK will return only one packet.
Based on xemul@ patches.
Signed-off-by: Stanislav Kinsbursky <skinsbursky@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
We switch generic-object-id concept with sys_kcmp approach,
which implies changes of image format a bit (and since it's
early time for project overall, we're allowed to).
In short -- previously every file descriptor had an ID
generated by a kernel and exported via procfs. If the
appropriate file descriptors were the same objects in
kernel memory -- the IDs did match up to bit. It allows
us to figure out which files were actually the identical
ones and should be restored in a special way.
Once sys_kcmp system call was merged into the kernel,
we've got a new opprotunity -- to use this syscall instead.
The syscall basically compares kernel objects and returns
ordered results suitable for objects sorting in a userspace.
For us it means -- we treat every file descriptor as a combination
of 'genid' and 'subid'. While 'genid' serves for fast comparison
between fds, the 'subid' is kind of a second key, which guarantees
uniqueness of genid+subid tuple over all file descritors found
in a process (or group of processes).
To be able to find and dump file descriptors in a single pass we
collect every fd into a global rbtree, where (!) each node might
become a root for a subtree as well.
The main tree carries only non-equal genid. If we find genid which
is already in tree, we need to make sure that it's either indeed
a duplicate or not. For this we use sys_kcmp syscall and if we
find that file descriptors are different -- we simply put new
fd into a subtree.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
This function simply allocates shared memory. Name it so
and move it closer to the variables it referes on.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Having them in the header file will allow to share these
structures with other callers. Moreover, this is a good
practice to have definition(s) in header file until otherwise
really needed.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Though we can use libc's syscall() wrapper
I would prefer to have own implementation
in case if we will need it in non-libc bindable
code.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Stack heap size is probably small for dumping unix sockest skb's (it's hard to
discover, how big it could be; thus let's assume that 10MB is enough,
otherwise give up and throw error).
So let' replace this stack heap wil 10 MB anonimous private mapping.
Signed-off-by: Stanislav Kinsbursky <skinsbursky@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
This is a place where they should belong to.
util.c is too big already.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
The ptrace seize doesn't prevent signals from delivery. That said,
we should block the signals in the target task before dumping
anything which is signals-related, i.e. memory and registers.
But once we've blocked signals, we should dump registers before
unblocking them, since any postponed signal will screw things up.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
This patch tries to introduce lazy and hidden pid_dir support,
meaning one don't have to worry about pid_dir but the optimization
is still there.
The patch relies on the fact that we work with many /proc/pid files for
one pid, then for another pid and so on, i.e. not in a random manner.
The idea is when we call open_proc() with a new pid for the first time,
the appropriate /proc/PID directory is opened and its fd is stored.
Next call to open_proc() with the same PID only need to check that
the PID is not changed. In case PID is changed, we close the old one
and open/store a new one.
Now the code using open_proc() and friends:
- does not need to carry proc_pid around, pid is enough
- does not need to call open_pid_proc()
The only thing that can't be done in that "lazy" mode is closing the last
PID fd, thus close_pid_proc().
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
...and make it correctly print the file name we were unable to open.
Also, error from fdopen[dir]() is now reported with file name as well.
Note that open_proc() and friends need to be macros in order for
pr_perror() to show actual file name and line number where error occured.
Historical note: the original version of this patch was way more radical,
changing openat() to open() and thus removing pid_dir (replacing with pid
when needed) and open_proc_dir(), changing openat() to open(). The word
from Pavel is he wants to keep the openat/pid_dir optimization because
it saves two dentry lookups in kernel code for each open(). Because of
this optimization (and desire to print correct file name in case
of error) we have to carry both pid and pid_dir everywhere.
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
To be used by the next patch
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
- make control block to keep all information
needed to run injected syscall and parasite
blobs
- add ptrace_swap_area helper
- handle both parasite engine calls and injected
syscalls by single __parasite_execute function
- drop jerr() usage
- bring back handling of inflight signals from
original program inside parasite code
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
This patch introduces the following changes:
1) writing of shmid value into vma_area->fd instead of
waiting for shared memory region is open by parent,
reopen it and dump fd.
2) new syscall support: sys_shmat
3) use sys_shmat() to map memory region in restorer's
mapping function if vma flag VMA_AREA_SYSVIPC is set.
Signed-off-by: Stanislav Kinsbursky <skinsbursky@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
This patch introduces the following changes:
1) introduces new flag VMA_AREA_SYSVIPC to mark corresponding vma entries.
2) enhance task /proc/<pid>/maps parsing to obtain first 5 letters of mapped
file. If device major file belong to ins equal to 0 (tmpfs) and it's name
starts with "/SYSV", then this mapping is considered as SYSV IPC and
corresponding vma entry status is updated with VMA_AREA_SYSVIPC flag.
3) omit dumping of mapping pages for SYSV IPC vmas.
Signed-off-by: Stanislav Kinsbursky <skinsbursky@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
These defines are already provided by unistd.h, and the only user
is log.c which already includes unistd.h.
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
v2: New "MSG_STEAL" functionality is used
Signed-off-by: Stanislav Kinsbursky <skinsbursky@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
They are not needed at moment but will be needed at
parasite/restorer code rework time, so add them now
just to not forget.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
This name for the structure is obfuscating, because the structure
will be used also for queues and semaphores sets migration.
This patch renames this structure int ipc_desc_entry. It also renames
all related functions and prints to reflect structure name change.
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Since we now have the parasite memory shared with crtools process we
can just memcpy this data between them.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
I don't like that we poke the parasite into remote space with 4k calls
to ptrace. Now we have the /proc/pid/map_files/ dir which helps us sharing
a mapping with some other process.
Use this -- map the remote area for parasite locally and put the parasite
blob into it with simple memcpy.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
There's no need in 3 instances of regs in arguments. One is more than enough.
Plus, this one can be made static.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Right now we do syscall_seized for this, but we have the misc dumping command
and the core is (after patch #3) dump after parasite, so we can get brk from
the misc dump, thus avoiding one more switch to parasite.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
This actually does two things:
1. The parasite code writes to pages _or_ to pages_shared file himself based
on a hint given from the main program. This avoids shared pages copying
in finalize_core.
2. The private pages are moved out of the core file into a separate one. This
avoids private pages copying in finalize_core.
The goal of this patch is a) to avoid pages copying at all (we still have
one on restore, but fixing this requires Andrey's work on shared memory
dumping) and b) make big blobs with pages be stored in separate files (I
have plans on its format rework and unification).
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Otherwise it become a global variable propagated
even to files where it must has no reference to
(such as parasite code)
Symbol table '.symtab' contains 22 entries:
Num: Value Size Type Bind Vis Ndx Name
...
4: 0000000000000000 0 FILE LOCAL DEFAULT ABS parasite.c
...
21: 000000000000b208 8 OBJECT GLOBAL DEFAULT 3 addr
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
v2: wrappers names become less obfuscating
This patch:
1) Updates function cr_fdset_open() to be suitable for handling fdset creation
for dump and show stages.
2) Replaces cr_fdset_open() by new wrapper function cr_fdset_dump().
3) Replaces prep_cr_fdset_for_restore() by new wrapper function cr_fdset_show().
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
This patch removes collect stage and dumps tunables object right after
collect.
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Unix diag and stat report dev_t-s in different formats. Cast one to
another when comparing in unix dumping.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
This patch adds ability to checkpoint/restore
/proc/pid/exe symlink, so if a process we've just
checkpointed has been say /path/to/exe, then at restore
time we bring this path back.
There some restiction from kernel side: if
existing /proc/pid/exe already mapped more than
once, the kernel will refuse to change the symlink,
so we need to restore it lately when mmaps of crtools
itself already unmapped (ie via late call in
restorer.c).
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Since we need to operate with sysctls pretty heavy,
better to add some common engine for all handlers.
Based-on-patch-from: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
