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/asm_linux_arm.s | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'src/syscall/asm_linux_arm.s') diff --git a/src/syscall/asm_linux_arm.s b/src/syscall/asm_linux_arm.s index 3252220562..d3995416c2 100644 --- a/src/syscall/asm_linux_arm.s +++ b/src/syscall/asm_linux_arm.s @@ -41,25 +41,25 @@ okseek: BL runtime·exitsyscall(SB) RET -// func rawVforkSyscall(trap, a1 uintptr) (r1, err uintptr) -TEXT ·rawVforkSyscall(SB),NOSPLIT|NOFRAME,$0-16 +// func rawVforkSyscall(trap, a1, a2 uintptr) (r1, err uintptr) +TEXT ·rawVforkSyscall(SB),NOSPLIT|NOFRAME,$0-20 MOVW trap+0(FP), R7 // syscall entry MOVW a1+4(FP), R0 - MOVW $0, R1 + MOVW a2+8(FP), R1 MOVW $0, R2 SWI $0 MOVW $0xfffff001, R1 CMP R1, R0 BLS ok MOVW $-1, R1 - MOVW R1, r1+8(FP) + MOVW R1, r1+12(FP) RSB $0, R0, R0 - MOVW R0, err+12(FP) + MOVW R0, err+16(FP) RET ok: - MOVW R0, r1+8(FP) + MOVW R0, r1+12(FP) MOVW $0, R0 - MOVW R0, err+12(FP) + MOVW R0, err+16(FP) RET // func rawSyscallNoError(trap uintptr, a1, a2, a3 uintptr) (r1, r2 uintptr); -- cgit v1.3