This also allows the tee(2) implementation to be enabled, since dup can now be
properly supported via WriteTo.
Note that this change necessitated some minor restructoring with the
fs.FileOperations splice methods. If the *fs.File is passed through directly,
then only public API methods are accessible, which will deadlock immediately
since the locking is already done by fs.Splice. Instead, we pass through an
abstract io.Reader or io.Writer, which elide locks and use the underlying
fs.FileOperations directly.
PiperOrigin-RevId: 268805207
Endpoint protocol goroutines were previously started as part of
loading the endpoint. This is potentially too soon, as resources used
by these goroutine may not have been loaded. Protocol goroutines may
perform meaningful work as soon as they're started (ex: incoming
connect) which can cause them to indirectly access resources that
haven't been loaded yet.
This CL defers resuming all protocol goroutines until the end of
restore.
PiperOrigin-RevId: 262409429
(Don't worry, this is mostly tests.)
Implemented the following ioctls:
- TIOCSCTTY - set controlling TTY
- TIOCNOTTY - remove controlling tty, maybe signal some other processes
- TIOCGPGRP - get foreground process group. Also enables tcgetpgrp().
- TIOCSPGRP - set foreground process group. Also enabled tcsetpgrp().
Next steps are to actually turn terminal-generated control characters (e.g. C^c)
into signals to the proper process groups, and to send SIGTTOU and SIGTTIN when
appropriate.
PiperOrigin-RevId: 261387276
We can get the mount namespace from the CreateProcessArgs in all cases where we
need it. This also gets rid of kernel.Destroy method, since the only thing it
was doing was DecRefing the mounts.
Removing the need to call kernel.SetRootMountNamespace also allowed for some
more simplifications in the container fs setup code.
PiperOrigin-RevId: 261357060
Adds feature to launch from an open host FD instead of a binary_path.
The FD should point to a valid executable and most likely be statically
compiled. If the executable is not statically compiled, the loader will
search along the interpreter paths, which must be able to be resolved in
the Sandbox's file system or start will fail.
PiperOrigin-RevId: 260756825
This introduces two new types of Emitters:
1. MultiEmitter, which will forward events to other registered Emitters, and
2. RateLimitedEmitter, which will forward events to a wrapped Emitter, subject
to given rate limits.
The methods in the eventchannel package itself act like a multiEmitter, but is
not actually an Emitter. Now we have a DefaultEmitter, and the methods in
eventchannel simply forward calls to the DefaultEmitter.
The unimplemented syscall handler now uses a RateLimetedEmitter that wraps the
DefaultEmitter.
PiperOrigin-RevId: 260612770
The different containers in a sandbox used only one pid
namespace before. This results in that a container can see
the processes in another container in the same sandbox.
This patch use different pid namespace for different containers.
Signed-off-by: chris.zn <chris.zn@antfin.com>
This renames FDMap to FDTable and drops the kernel.FD type, which had an entire
package to itself and didn't serve much use (it was freely cast between types,
and served as more of an annoyance than providing any protection.)
Based on BenchmarkFDLookupAndDecRef-12, we can expect 5-10 ns per lookup
operation, and 10-15 ns per concurrent lookup operation of savings.
This also fixes two tangential usage issues with the FDMap. Namely, non-atomic
use of NewFDFrom and associated calls to Remove (that are both racy and fail to
drop the reference on the underlying file.)
PiperOrigin-RevId: 256285890
Get/Set pipe size and ioctl support were missing from
overlayfs. It required moving the pipe.Sizer interface
to fs so that overlay could get access.
Fixes#318
PiperOrigin-RevId: 255511125
Addresses obvious typos, in the documentation only.
COPYBARA_INTEGRATE_REVIEW=https://github.com/google/gvisor/pull/443 from Pixep:fix/documentation-spelling 4d0688164eafaf0b3010e5f4824b35d1e7176d65
PiperOrigin-RevId: 255477779
Credentials are immutable and even before these changes we could read them
without locks, but we needed to take a task lock to get a credential object
from a task object.
It is possible to avoid this lock, if we will guarantee that a credential
object will not be changed after setting it on a task.
PiperOrigin-RevId: 254989492
We don't have the plumbing for btime yet, so that field is left off. The
returned mask indicates that btime is absent.
Fixes#343
PiperOrigin-RevId: 254575752
This allows tasks to have distinct mount namespace, instead of all sharing the
kernel's root mount namespace.
Currently, the only way for a task to get a different mount namespace than the
kernel's root is by explicitly setting a different MountNamespace in
CreateProcessArgs, and nothing does this (yet).
In a follow-up CL, we will set CreateProcessArgs.MountNamespace when creating a
new container inside runsc.
Note that "MountNamespace" is a poor term for this thing. It's more like a
distinct VFS tree. When we get around to adding real mount namespaces, this
will need a better naem.
PiperOrigin-RevId: 254009310
sockets, pipes and other non-seekable file descriptors don't
use file.offset, so we don't need to update it.
With this change, we will be able to call file operations
without locking the file.mu mutex. This is already used for
pipes in the splice system call.
PiperOrigin-RevId: 253746644
When leader of process group (session) exit, the process
group ID (session ID) is holding by other processes in
the process group, so the process group ID (session ID)
can not be reused.
If reusing the process group ID (seession ID) as new process
group ID for new process, this will cause session create
failed, and later runsc crash when access process group.
The fix skip the tid if it is using by a process group
(session) when allocating a new tid.
We could easily reproduce the runsc crash follow
these steps:
1. build test program, and run inside container
int main(int argc, char *argv[])
{
pid_t cpid, spid;
cpid = fork();
if (cpid == -1) {
perror("fork");
exit(EXIT_FAILURE);
}
if (cpid == 0) {
pid_t sid = setsid();
printf("Start New Session %ld\n",sid);
printf("Child PID %ld / PPID %ld / PGID %ld / SID %ld\n",
getpid(),getppid(),getpgid(getpid()),getsid(getpid()));
spid = fork();
if (spid == 0) {
setpgid(getpid(), getpid());
printf("Set GrandSon as New Process Group\n");
printf("GrandSon PID %ld / PPID %ld / PGID %ld / SID %ld\n",
getpid(),getppid(),getpgid(getpid()),getsid(getpid()));
while(1) {
usleep(1);
}
}
sleep(3);
exit(0);
} else {
exit(0);
}
return 0;
}
2. build hello program
int main(int argc, char *argv[])
{
printf("Current PID is %ld\n", (long) getpid());
return 0;
}
3. run script on host which run hello inside container, you can
speed up the test with set TasksLimit as lower value.
for (( i=0; i<65535; i++ ))
do
docker exec <container id> /test/hello
done
4. when hello process reusing the process group of loop process,
runsc will crash.
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x79f0c8]
goroutine 612475 [running]:
gvisor.googlesource.com/gvisor/pkg/sentry/kernel.(*ProcessGroup).decRefWithParent(0x0, 0x0)
pkg/sentry/kernel/sessions.go:160 +0x78
gvisor.googlesource.com/gvisor/pkg/sentry/kernel.(*Task).exitNotifyLocked(0xc000663500, 0x0)
pkg/sentry/kernel/task_exit.go:672 +0x2b7
gvisor.googlesource.com/gvisor/pkg/sentry/kernel.(*runExitNotify).execute(0x0, 0xc000663500, 0x0, 0x0)
pkg/sentry/kernel/task_exit.go:542 +0xc4
gvisor.googlesource.com/gvisor/pkg/sentry/kernel.(*Task).run(0xc000663500, 0xc)
pkg/sentry/kernel/task_run.go:91 +0x194
created by gvisor.googlesource.com/gvisor/pkg/sentry/kernel.(*Task).Start
pkg/sentry/kernel/task_start.go:286 +0xfe
The deadlock can occur when both ends of a connected Unix socket which has
FIOASYNC enabled on at least one end are closed at the same time. One end
notifies that it is closing, calling (*waiter.Queue).Notify which takes
waiter.Queue.mu (as a read lock) and then calls (*FileAsync).Callback, which
takes FileAsync.mu. The other end tries to unregister for notifications by
calling (*FileAsync).Unregister, which takes FileAsync.mu and calls
(*waiter.Queue).EventUnregister which takes waiter.Queue.mu.
This is fixed by moving the calls to waiter.Waitable.EventRegister and
waiter.Waitable.EventUnregister outside of the protection of any mutex used
in (*FileAsync).Callback.
The new test is related, but does not cover this particular situation.
Also fix a data race on FileAsync.e.Callback. (*FileAsync).Callback checked
FileAsync.e.Callback under the protection of FileAsync.mu, but the waiter
calling (*FileAsync).Callback could not and did not. This is fixed by making
FileAsync.e.Callback immutable before passing it to the waiter for the first
time.
Fixes#346
PiperOrigin-RevId: 253138340
Adds simple introspection for syscall compatibility information to Linux/AMD64.
Syscalls registered in the syscall table now have associated metadata like
name, support level, notes, and URLs to relevant issues.
Syscall information can be exported as a table, JSON, or CSV using the new
'runsc help syscalls' command. Users can use this info to debug and get info
on the compatibility of the version of runsc they are running or to generate
documentation.
PiperOrigin-RevId: 252558304
Store enough information in the kernel socket table to distinguish
between different types of sockets. Previously we were only storing
the socket family, but this isn't enough to classify sockets. For
example, TCPv4 and UDPv4 sockets are both AF_INET, and ICMP sockets
are SOCK_DGRAM sockets with a particular protocol.
Instead of creating more sub-tables, flatten the socket table and
provide a filtering mechanism based on the socket entry.
Also generate and store a socket entry index ("sl" in linux) which
allows us to output entries in a stable order from procfs.
PiperOrigin-RevId: 252495895
We still only advertise a single NUMA node, and ignore mempolicy
accordingly, but mbind() at least now succeeds and has effects reflected
by get_mempolicy().
Also fix handling of nodemasks: round sizes to unsigned long (as
documented and done by Linux), and zero trailing bits when copying them
out.
PiperOrigin-RevId: 251950859
We don't actually support core dumps, but some applications want to
get/set dumpability, which still has an effect in procfs.
Lack of support for set-uid binaries or fs creds simplifies things a
bit.
As-is, processes started via CreateProcess (i.e., init and sentryctl
exec) have normal dumpability. I'm a bit torn on whether sentryctl exec
tasks should be dumpable, but at least since they have no parent normal
UID/GID checks should protect them.
PiperOrigin-RevId: 251712714
When pipe is created, a dirent of pipe will be
created and its initial reference is set as 0.
Cause all dirent will only be destroyed when
the reference decreased to -1, so there is already
a 'initial reference' of dirent after it created.
For destroying dirent after all reference released,
the correct way is to drop the 'initial reference'
once someone hold a reference to the dirent, such
as fs.NewFile, otherwise the reference of dirent
will stay 0 all the time, and will cause memory
leak of dirent.
Except pipe, timerfd/eventfd/epoll has the same
problem
Here is a simple case to create memory leak of dirent
for pipe/timerfd/eventfd/epoll in C langange, after
run the case, pprof the runsc process, you will
find lots dirents of pipe/timerfd/eventfd/epoll not
freed:
int main(int argc, char *argv[])
{
int i;
int n;
int pipefd[2];
if (argc != 3) {
printf("Usage: %s epoll|timerfd|eventfd|pipe <iterations>\n", argv[0]);
}
n = strtol(argv[2], NULL, 10);
if (strcmp(argv[1], "epoll") == 0) {
for (i = 0; i < n; ++i)
close(epoll_create(1));
} else if (strcmp(argv[1], "timerfd") == 0) {
for (i = 0; i < n; ++i)
close(timerfd_create(CLOCK_REALTIME, 0));
} else if (strcmp(argv[1], "eventfd") == 0) {
for (i = 0; i < n; ++i)
close(eventfd(0, 0));
} else if (strcmp(argv[1], "pipe") == 0) {
for (i = 0; i < n; ++i)
if (pipe(pipefd) == 0) {
close(pipefd[0]);
close(pipefd[1]);
}
}
printf("%s %s test finished\r\n",argv[1],argv[2]);
return 0;
}
Change-Id: Ia1b8a1fb9142edb00c040e44ec644d007f81f5d2
PiperOrigin-RevId: 251531096
Dirents are ref-counted, but Pipes are not. Holding a Dirent inside of a Pipe
raises difficult questions about the lifecycle of the Pipe and Dirent.
Fortunately, we can side-step those questions by removing the Dirent field from
Pipe entirely. We only need the Dirent when constructing fs.Files (which are
ref-counted), and in GetFile (when a Dirent is passed to us anyways).
PiperOrigin-RevId: 251497628
After bf959931ddb88c4e4366e96dd22e68fa0db9527c ("wait/ptrace: assume
__WALL if the child is traced") (Linux 4.7), tracees are always eligible
for waiting, regardless of type.
PiperOrigin-RevId: 250399527
sendfile can be called for a big range and it can require significant
amount of time to process it, so we need to handle task interrupts in
this system call.
PiperOrigin-RevId: 249781023
Change-Id: Ifc2ec505d74c06f5ee76f93b8d30d518ec2d4015
Pipe internals are made more efficient by avoiding garbage collection.
A pool is now used that can be shared by all pipes, and buffers are
chained via an intrusive list. The documentation for pipe structures
and methods is also simplified and clarified.
The pipe tests are now parameterized, so that they are run on all
different variants (named pipes, small buffers, default buffers).
The pipe buffer sizes are exposed by fcntl, which is now supported
by this change. A size change test has been added to the suite.
These new tests uncovered a bug regarding the semantics of open
named pipes with O_NONBLOCK, which is also fixed by this CL. This
fix also addresses the lack of the O_LARGEFILE flag for named pipes.
PiperOrigin-RevId: 249375888
Change-Id: I48e61e9c868aedb0cadda2dff33f09a560dee773
This does not actually implement an efficient splice or sendfile. Rather, it
adds a generic plumbing to the file internals so that this can be added. All
file implementations use the stub fileutil.NoSplice implementation, which
causes sendfile and splice to fall back to an internal copy.
A basic splice system call interface is added, along with a test.
PiperOrigin-RevId: 249335960
Change-Id: Ic5568be2af0a505c19e7aec66d5af2480ab0939b
This feature allows MemoryFile to delay eviction of "optional"
allocations, such as unused cached file pages.
Note that this incidentally makes CachingInodeOperations writeback
asynchronous, in the sense that it doesn't occur until eviction; this is
necessary because between when a cached page becomes evictable and when
it's evicted, file writes (via CachingInodeOperations.Write) may dirty
the page.
As currently implemented, this feature won't meaningfully impact
steady-state memory usage or caching; the reclaimer goroutine will
schedule eviction as soon as it runs out of other work to do. Future CLs
increase caching by adding constraints on when eviction is scheduled.
PiperOrigin-RevId: 246014822
Change-Id: Ia85feb25a2de92a48359eb84434b6ec6f9bea2cb
Based on the guidelines at
https://opensource.google.com/docs/releasing/authors/.
1. $ rg -l "Google LLC" | xargs sed -i 's/Google LLC.*/The gVisor Authors./'
2. Manual fixup of "Google Inc" references.
3. Add AUTHORS file. Authors may request to be added to this file.
4. Point netstack AUTHORS to gVisor AUTHORS. Drop CONTRIBUTORS.
Fixes#209
PiperOrigin-RevId: 245823212
Change-Id: I64530b24ad021a7d683137459cafc510f5ee1de9
Adin Scannell
Michael Pratt
Bhasker Hariharan
Rahat Mahmood
Kevin Krakauer
Nicolas Lacasse
Zach Koopmans
gVisor bot
chris.zn
Neel Natu
Ahmet Alp Balkan
Ian Gudger
Fabricio Voznika
Andrei Vagin
Yong He
Ian Lewis
Jamie Liu