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go/misc/cgo/test/cgo_linux_test.go

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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package cgotest
import (
"os"
"runtime"
"testing"
)
func TestSetgid(t *testing.T) {
if runtime.GOOS == "android" {
t.Skip("unsupported on Android")
}
if _, err := os.Stat("/etc/alpine-release"); err == nil {
t.Skip("setgid is broken with musl libc - go.dev/issue/39857")
}
testSetgid(t)
}
cmd/internal/obj/arm64: save LR and SP in one instruction for small frames When we create a thread with signals blocked. But glibc's pthread_sigmask doesn't really allow us to block SIGSETXID. So we may get a signal early on before the signal stack is set. If we get a signal on the current stack, it will clobber anything below the SP. This CL makes it to save LR and decrement SP in a single MOVD.W instruction for small frames, so we don't write below the SP. We used to use a single MOVD.W instruction before CL 379075. CL 379075 changed to use an STP instruction to save the LR and FP, then decrementing the SP. This CL changes it back, just this part (epilogues and large frame prologues are unchanged). For small frames, it is the same number of instructions either way. This decreases the size of a "small" frame from 0x1f0 to 0xf0. For frame sizes in between, it could benefit from using an STP instruction instead of using the prologue for the "large" frame case. We don't bother it for now as this is a stop-gap solution anyway. This only addresses the issue with small frames. Luckily, all functions from thread entry to setting up the signal stack have samll frames. Other possible ideas: - Expand the unwind info metadata, separate SP delta and the location of the return address, so we can express "SP is decremented but the return address is in the LR register". Then we can always create the frame first then write the LR, without writing anything below the SP (except the frame pointer at SP-8, which is minor because it doesn't really affect program execution). - Set up the signal stack immediately in mstart in assembly. For Go 1.19 we do this simple fix. We plan to do the metadata fix in Go 1.20 ( #53609 ). Other LR architectures are addressed in CL 413428. Fix #53374. Change-Id: I9d6582ab14ccb06ac61ad43852943d9555e22ae5 Reviewed-on: https://go-review.googlesource.com/c/go/+/412474 Run-TryBot: Cherry Mui <cherryyz@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Austin Clements <austin@google.com> Reviewed-by: Eric Fang <eric.fang@arm.com>
2022-06-15 13:09:24 -06:00
func TestSetgidStress(t *testing.T) {
if runtime.GOOS == "android" {
t.Skip("unsupported on Android")
}
if _, err := os.Stat("/etc/alpine-release"); err == nil {
t.Skip("setgid is broken with musl libc - go.dev/issue/39857")
}
cmd/internal/obj/arm64: save LR and SP in one instruction for small frames When we create a thread with signals blocked. But glibc's pthread_sigmask doesn't really allow us to block SIGSETXID. So we may get a signal early on before the signal stack is set. If we get a signal on the current stack, it will clobber anything below the SP. This CL makes it to save LR and decrement SP in a single MOVD.W instruction for small frames, so we don't write below the SP. We used to use a single MOVD.W instruction before CL 379075. CL 379075 changed to use an STP instruction to save the LR and FP, then decrementing the SP. This CL changes it back, just this part (epilogues and large frame prologues are unchanged). For small frames, it is the same number of instructions either way. This decreases the size of a "small" frame from 0x1f0 to 0xf0. For frame sizes in between, it could benefit from using an STP instruction instead of using the prologue for the "large" frame case. We don't bother it for now as this is a stop-gap solution anyway. This only addresses the issue with small frames. Luckily, all functions from thread entry to setting up the signal stack have samll frames. Other possible ideas: - Expand the unwind info metadata, separate SP delta and the location of the return address, so we can express "SP is decremented but the return address is in the LR register". Then we can always create the frame first then write the LR, without writing anything below the SP (except the frame pointer at SP-8, which is minor because it doesn't really affect program execution). - Set up the signal stack immediately in mstart in assembly. For Go 1.19 we do this simple fix. We plan to do the metadata fix in Go 1.20 ( #53609 ). Other LR architectures are addressed in CL 413428. Fix #53374. Change-Id: I9d6582ab14ccb06ac61ad43852943d9555e22ae5 Reviewed-on: https://go-review.googlesource.com/c/go/+/412474 Run-TryBot: Cherry Mui <cherryyz@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Austin Clements <austin@google.com> Reviewed-by: Eric Fang <eric.fang@arm.com>
2022-06-15 13:09:24 -06:00
testSetgidStress(t)
}
syscall: support POSIX semantics for Linux syscalls This change adds two new methods for invoking system calls under Linux: syscall.AllThreadsSyscall() and syscall.AllThreadsSyscall6(). These system call wrappers ensure that all OSThreads mirror a common system call. The wrappers serialize execution of the runtime to ensure no race conditions where any Go code observes a non-atomic OS state change. As such, the syscalls have higher runtime overhead than regular system calls, and only need to be used where such thread (or 'm' in the parlance of the runtime sources) consistency is required. The new support is used to enable these functions under Linux: syscall.Setegid(), syscall.Seteuid(), syscall.Setgroups(), syscall.Setgid(), syscall.Setregid(), syscall.Setreuid(), syscall.Setresgid(), syscall.Setresuid() and syscall.Setuid(). They work identically to their glibc counterparts. Extensive discussion of the background issue addressed in this patch can be found here: https://github.com/golang/go/issues/1435 In the case where cgo is used, the C runtime can launch pthreads that are not managed by the Go runtime. As such, the added syscall.AllThreadsSyscall*() return ENOTSUP when cgo is enabled. However, for the 9 syscall.Set*() functions listed above, when cgo is active, these functions redirect to invoke their C.set*() equivalents in glibc, which wraps the raw system calls with a nptl:setxid fixup mechanism. This achieves POSIX semantics for these functions in the combined Go and C runtime. As a side note, the glibc/nptl:setxid support (2019-11-30) does not extend to all security related system calls under Linux so using native Go (CGO_ENABLED=0) and these AllThreadsSyscall*()s, where needed, will yield more well defined/consistent behavior over all threads of a Go program. That is, using the syscall.AllThreadsSyscall*() wrappers for things like setting state through SYS_PRCTL and SYS_CAPSET etc. Fixes #1435 Change-Id: Ib1a3e16b9180f64223196a32fc0f9dce14d9105c Reviewed-on: https://go-review.googlesource.com/c/go/+/210639 Trust: Emmanuel Odeke <emm.odeke@gmail.com> Trust: Ian Lance Taylor <iant@golang.org> Trust: Michael Pratt <mpratt@google.com> Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com> Reviewed-by: Michael Pratt <mpratt@google.com> Reviewed-by: Austin Clements <austin@google.com>
2019-12-09 22:50:16 -07:00
func Test1435(t *testing.T) { test1435(t) }
func Test6997(t *testing.T) { test6997(t) }
func TestBuildID(t *testing.T) { testBuildID(t) }