(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
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
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
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
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
If there are thousands of threads, ThreadGroupsAppend becomes very
expensive as it must iterate over all Tasks to find the ThreadGroup
leaders.
Reduce the cost by maintaining a map of ThreadGroups which can be used
to grab them all directly.
The one somewhat visible change is to convert PID namespace init
children zapping to a group-directed SIGKILL, as Linux did in
82058d668465 "signal: Use group_send_sig_info to kill all processes in a
pid namespace".
In a benchmark that creates N threads which sleep for two minutes, we
see approximately this much CPU time in ThreadGroupsAppend:
Before:
1 thread: 0ms
1024 threads: 30ms - 9130ms
4096 threads: 50ms - 2000ms
8192 threads: 18160ms
16384 threads: 17210ms
After:
1 thread: 0ms
1024 threads: 0ms
4096 threads: 0ms
8192 threads: 0ms
16384 threads: 0ms
The profiling is actually extremely noisy (likely due to cache effects),
as some runs show almost no samples at 1024, 4096 threads, but obviously
this does not scale to lots of threads.
PiperOrigin-RevId: 241828039
Change-Id: I17827c90045df4b3c49b3174f3a05bca3026a72c
In order to implement kill --all correctly, the Sentry needs
to track all tasks that belong to a given container. This change
introduces ContainerID to the task, that gets inherited by all
children. 'kill --all' then iterates over all tasks comparing the
ContainerID field to find all processes that need to be signalled.
PiperOrigin-RevId: 214841768
Change-Id: I693b2374be8692d88cc441ef13a0ae34abf73ac6
This allows us to call kernel.FDMap.DecRef without holding mutexes
cleanly.
PiperOrigin-RevId: 211139657
Change-Id: Ie59d5210fb9282e1950e2e40323df7264a01bcec
Kevin Krakauer
gVisor bot
Adin Scannell
Andrei Vagin
Yong He
Michael Pratt
Ian Gudger
Fabricio Voznika
Jamie Liu
Googler