From bca17d16ca0dabbe1b533bb78f367d64e076fe73 Mon Sep 17 00:00:00 2001 From: Kir Kolyshkin Date: Thu, 14 Jul 2022 21:18:15 -0700 Subject: syscall: add CgroupFD support for ForkExec on Linux Implement CLONE_INTO_CGROUP feature, allowing to put a child in a specified cgroup in a clean and simple way. Note that the feature only works for cgroup v2, and requires Linux kernel 5.7 or newer. Using the feature requires a new syscall, clone3. Currently this is the only reason to use clone3, but the code is structured in a way so that other cases may be easily added in the future. Add a test case. While at it, try to simplify the syscall calling code in forkAndExecInChild1, which became complicated over time because: 1. It was using either rawVforkSyscall or RawSyscall6 depending on whether CLONE_NEWUSER was set. 2. On Linux/s390, the first two arguments to clone(2) system call are swapped (which deserved a mention in Linux ABI hall of shame). It was worked around in rawVforkSyscall on s390, but had to be implemented via a switch/case when using RawSyscall6, making the code less clear. Let's - modify rawVforkSyscall to have two arguments (which is also required for clone3); - remove the arguments workaround from s390 asm, instead implementing arguments swap in the caller (which still looks ugly but at least it's done once and is clearly documented now); - use rawVforkSyscall for all cases (since it is essentially similar to RawSyscall6, except for having less parameters, not returning r2, and saving/restoring the return address before/after syscall on 386 and amd64). Updates #51246. Change-Id: Ifcd418ebead9257177338ffbcccd0bdecb94474e Reviewed-on: https://go-review.googlesource.com/c/go/+/417695 Auto-Submit: Ian Lance Taylor Reviewed-by: Michael Knyszek Reviewed-by: Ian Lance Taylor Run-TryBot: Ian Lance Taylor Run-TryBot: Kirill Kolyshkin TryBot-Result: Gopher Robot --- src/syscall/syscall_linux.go | 1 + 1 file changed, 1 insertion(+) (limited to 'src/syscall/syscall_linux.go') diff --git a/src/syscall/syscall_linux.go b/src/syscall/syscall_linux.go index c3038fc09a..bdee570dda 100644 --- a/src/syscall/syscall_linux.go +++ b/src/syscall/syscall_linux.go @@ -94,6 +94,7 @@ func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno) } func rawSyscallNoError(trap, a1, a2, a3 uintptr) (r1, r2 uintptr) +func rawVforkSyscall(trap, a1, a2 uintptr) (r1 uintptr, err Errno) /* * Wrapped -- cgit v1.3