Use Process.handle field to store pidfd, and make use of it. Only use
pidfd functionality if all the needed syscalls are available.
1. Add/use pidfdWorks, which checks that all needed pidfd-related
functionality works.
2. os.StartProcess: obtain the pidfd from the kernel, if possible, using
the functionality added by CL 520266. Note we could not modify
syscall.StartProcess to return pidfd directly because it is a public
API and its callers do not expect it, so we have to use ensurePidfd
and getPidfd.
3. (*Process).Kill: use pidfdSendSignal, if available and the pidfd is
known. Otherwise, fall back to the old implementation.
4. (*Process).Wait: use pidfdWait, if available, otherwise fall back to
using waitid/wait4. This is more complicated than expected due to
struct siginfo_t idiosyncrasy.
NOTE pidfdSendSignal and pidfdWait are used without a race workaround
(blockUntilWaitable and sigMu, added by CL 23967) because with pidfd,
PID recycle issue doesn't exist (IOW, pidfd, unlike PID, is guaranteed
to refer to one particular process) and thus the race doesn't exist
either.
Rework of CL 528438 (reverted in CL 566477 because of #65857).
For #62654.
Updates #13987.
Change-Id: If5ef8920bd8619dc428b6282ffe4fb8c258ca224
Reviewed-on: https://go-review.googlesource.com/c/go/+/570036
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Kirill Kolyshkin <kolyshkin@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Cherry Mui <cherryyz@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
This reverts CL 528438.
Reason for revert: Implicated in "bad FD" test failures. Full extent of
issue still unclear.
For #62654.
Fixes#65857.
Change-Id: I066e38040544c506917e90255bd0e330964a0276
Reviewed-on: https://go-review.googlesource.com/c/go/+/566477
Auto-Submit: Michael Pratt <mpratt@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Use Process.handle field to store pidfd, and make use of it. Only use
pidfd functionality if all the needed syscalls are available.
1. StartProcess: obtain the pidfd from the kernel, if available,
using the functionality added by CL 520266. Note we could not modify
syscall.StartProcess to return pidfd directly because it is a public
API and its callers do not expect it, so we have to use ensurePidfd
and getPidfd.
2. (*Process).Kill: use pidfdSendSignal, if the syscall is available
and pidfd is known. This is slightly more complicated than it should
be, since the syscall can be blocked by e.g. seccomp security policy,
therefore the need for a function to check if it's actually working,
and a soft fallback to kill. Perhaps this precaution is not really
needed.
3. (*Process).Wait: use pidfdWait, if available, otherwise fall back to
using waitid/wait4. This is also more complicated than expected due
to struct siginfo_t idiosyncrasy.
NOTE pidfdSendSignal and pidfdWait are used without a race workaround
(blockUntilWaitable and sigMu, added by CL 23967) because with pidfd,
PID recycle issue doesn't exist (IOW, pidfd, unlike PID, is guaranteed
to refer to one particular process) and thus the race doesn't exist
either.
For #62654.
Updates #13987.
Change-Id: I22ebcc7142b16a3a94c422d2f32504d1a80e8a8f
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Reviewed-on: https://go-review.googlesource.com/c/go/+/528438
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
CL 520266 added pidfd_send_signal linux syscall numbers to the
syscall package for the sake of a unit test.
As pidfd_send_signal will be used from the os package, let's revert the
changes to syscall package, add the pidfd_send_signal syscall numbers
and the implementation to internal/syscall/unix, and change the above
test to use it.
Updates #51246.
For #62654.
Change-Id: I862174c3c1a64baf1080792bdb3a1c1d1b417bb4
Reviewed-on: https://go-review.googlesource.com/c/go/+/528436
Run-TryBot: Kirill Kolyshkin <kolyshkin@gmail.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Michael Pratt <mpratt@google.com>
