[release-branch.go1.18] runtime: revert "call __fork instead of fork on darwin"
A recent comment on #57263 reports an unexplained crash in a cgo program
that is fixed by reverting the __fork fix. We don't have any viable fix for the
os/exec bug at this point, so give up on a fix for the January point releases.
This reverts CL 459179 (commit 07b6ffb79c90).
Fixes #57689.
Change-Id: I3b81de6bded399f47862325129e86a65c83d8e3b
Reviewed-on: https://go-review.googlesource.com/c/go/+/461116
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
diff --git a/src/syscall/exec_libc2.go b/src/syscall/exec_libc2.go
index bd2ce68..b05f053 100644
--- a/src/syscall/exec_libc2.go
+++ b/src/syscall/exec_libc2.go
@@ -76,7 +76,7 @@
// About to call fork.
// No more allocation or calls of non-assembly functions.
runtime_BeforeFork()
- r1, _, err1 = rawSyscall(forkTrampoline, 0, 0, 0)
+ r1, _, err1 = rawSyscall(abi.FuncPCABI0(libc_fork_trampoline), 0, 0, 0)
if err1 != 0 {
runtime_AfterFork()
return 0, err1
@@ -260,6 +260,6 @@
// send error code on pipe
rawSyscall(abi.FuncPCABI0(libc_write_trampoline), uintptr(pipe), uintptr(unsafe.Pointer(&err1)), unsafe.Sizeof(err1))
for {
- rawSyscall(exitTrampoline, 253, 0, 0)
+ rawSyscall(abi.FuncPCABI0(libc_exit_trampoline), 253, 0, 0)
}
}
diff --git a/src/syscall/syscall_darwin.go b/src/syscall/syscall_darwin.go
index 346e686..902d6e7 100644
--- a/src/syscall/syscall_darwin.go
+++ b/src/syscall/syscall_darwin.go
@@ -17,34 +17,6 @@
"unsafe"
)
-// These are called from exec_libc2.go in the child of fork.
-// The names differ between macOS and OpenBSD, so we need
-// to declare the specific ones used here to keep the exec_libc2.go
-// code portable.
-//
-// We use __fork and __exit, not fork and exit, to avoid the libc atfork
-// and atexit handlers. The atfork handlers have caused fork child
-// hangs in the past (see #33565, #56784). The atexit handlers have
-// not, but the non-libc ports all invoke the system call, so doing
-// the same here makes sense. In general we wouldn't expect
-// atexit handlers to work terribly well in a fork child anyway.
-// (Also, perhaps the atfork handlers clear the atexit handlers,
-// in which case we definitely need to avoid calling the libc exit
-// if we bypass the libc fork.)
-//
-// Other calls that are made in the child after the fork are
-// ptrace, setsid, setpgid, getpid, ioctl, chroot, setgroups,
-// setgid, setuid, chdir, dup2, fcntl, close, execve, and write.
-// Those are all simple kernel wrappers that should be safe
-// to be called directly. The fcntl and ioctl functions do run
-// some code around the kernel call, but they don't call any
-// other functions, so for now we keep using them instead of
-// calling the lower-level __fcntl and __ioctl functions.
-var (
- exitTrampoline = abi.FuncPCABI0(libc___exit_trampoline)
- forkTrampoline = abi.FuncPCABI0(libc___fork_trampoline)
-)
-
type SockaddrDatalink struct {
Len uint8
Family uint8
@@ -230,12 +202,11 @@
//sys writev(fd int, iovecs []Iovec) (cnt uintptr, err error)
//sys mmap(addr uintptr, length uintptr, prot int, flag int, fd int, pos int64) (ret uintptr, err error)
//sys munmap(addr uintptr, length uintptr) (err error)
-//sysnb __fork() (pid int, err error)
+//sysnb fork() (pid int, err error)
//sysnb ioctl(fd int, req int, arg int) (err error)
//sysnb ioctlPtr(fd int, req uint, arg unsafe.Pointer) (err error) = SYS_ioctl
//sysnb execve(path *byte, argv **byte, envp **byte) (err error)
//sysnb exit(res int) (err error)
-//sysnb __exit(res int) (err error)
//sys sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error)
//sys fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (val int, err error) = SYS_fcntl
//sys unlinkat(fd int, path string, flags int) (err error)
diff --git a/src/syscall/syscall_openbsd_libc.go b/src/syscall/syscall_openbsd_libc.go
index ff9fa00..15b68fd 100644
--- a/src/syscall/syscall_openbsd_libc.go
+++ b/src/syscall/syscall_openbsd_libc.go
@@ -10,11 +10,6 @@
"internal/abi"
)
-var (
- exitTrampoline = abi.FuncPCABI0(libc_exit_trampoline)
- forkTrampoline = abi.FuncPCABI0(libc_fork_trampoline)
-)
-
func init() {
execveOpenBSD = execve
}
diff --git a/src/syscall/zsyscall_darwin_amd64.go b/src/syscall/zsyscall_darwin_amd64.go
index 2ad0380..0ccdaf2 100644
--- a/src/syscall/zsyscall_darwin_amd64.go
+++ b/src/syscall/zsyscall_darwin_amd64.go
@@ -1714,8 +1714,8 @@
// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-func __fork() (pid int, err error) {
- r0, _, e1 := rawSyscall(abi.FuncPCABI0(libc___fork_trampoline), 0, 0, 0)
+func fork() (pid int, err error) {
+ r0, _, e1 := rawSyscall(abi.FuncPCABI0(libc_fork_trampoline), 0, 0, 0)
pid = int(r0)
if e1 != 0 {
err = errnoErr(e1)
@@ -1723,9 +1723,9 @@
return
}
-func libc___fork_trampoline()
+func libc_fork_trampoline()
-//go:cgo_import_dynamic libc___fork __fork "/usr/lib/libSystem.B.dylib"
+//go:cgo_import_dynamic libc_fork fork "/usr/lib/libSystem.B.dylib"
// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
@@ -1781,20 +1781,6 @@
// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-func __exit(res int) (err error) {
- _, _, e1 := rawSyscall(abi.FuncPCABI0(libc___exit_trampoline), uintptr(res), 0, 0)
- if e1 != 0 {
- err = errnoErr(e1)
- }
- return
-}
-
-func libc___exit_trampoline()
-
-//go:cgo_import_dynamic libc___exit __exit "/usr/lib/libSystem.B.dylib"
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
func sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error) {
var _p0 unsafe.Pointer
if len(mib) > 0 {
diff --git a/src/syscall/zsyscall_darwin_amd64.s b/src/syscall/zsyscall_darwin_amd64.s
index 1815703..563083d 100644
--- a/src/syscall/zsyscall_darwin_amd64.s
+++ b/src/syscall/zsyscall_darwin_amd64.s
@@ -219,16 +219,14 @@
JMP libc_mmap(SB)
TEXT ·libc_munmap_trampoline(SB),NOSPLIT,$0-0
JMP libc_munmap(SB)
-TEXT ·libc___fork_trampoline(SB),NOSPLIT,$0-0
- JMP libc___fork(SB)
+TEXT ·libc_fork_trampoline(SB),NOSPLIT,$0-0
+ JMP libc_fork(SB)
TEXT ·libc_ioctl_trampoline(SB),NOSPLIT,$0-0
JMP libc_ioctl(SB)
TEXT ·libc_execve_trampoline(SB),NOSPLIT,$0-0
JMP libc_execve(SB)
TEXT ·libc_exit_trampoline(SB),NOSPLIT,$0-0
JMP libc_exit(SB)
-TEXT ·libc___exit_trampoline(SB),NOSPLIT,$0-0
- JMP libc___exit(SB)
TEXT ·libc_sysctl_trampoline(SB),NOSPLIT,$0-0
JMP libc_sysctl(SB)
TEXT ·libc_unlinkat_trampoline(SB),NOSPLIT,$0-0
diff --git a/src/syscall/zsyscall_darwin_arm64.go b/src/syscall/zsyscall_darwin_arm64.go
index 559bb49..09bf34b 100644
--- a/src/syscall/zsyscall_darwin_arm64.go
+++ b/src/syscall/zsyscall_darwin_arm64.go
@@ -1714,8 +1714,8 @@
// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-func __fork() (pid int, err error) {
- r0, _, e1 := rawSyscall(abi.FuncPCABI0(libc___fork_trampoline), 0, 0, 0)
+func fork() (pid int, err error) {
+ r0, _, e1 := rawSyscall(abi.FuncPCABI0(libc_fork_trampoline), 0, 0, 0)
pid = int(r0)
if e1 != 0 {
err = errnoErr(e1)
@@ -1723,9 +1723,9 @@
return
}
-func libc___fork_trampoline()
+func libc_fork_trampoline()
-//go:cgo_import_dynamic libc___fork __fork "/usr/lib/libSystem.B.dylib"
+//go:cgo_import_dynamic libc_fork fork "/usr/lib/libSystem.B.dylib"
// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
@@ -1781,20 +1781,6 @@
// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-func __exit(res int) (err error) {
- _, _, e1 := rawSyscall(abi.FuncPCABI0(libc___exit_trampoline), uintptr(res), 0, 0)
- if e1 != 0 {
- err = errnoErr(e1)
- }
- return
-}
-
-func libc___exit_trampoline()
-
-//go:cgo_import_dynamic libc___exit __exit "/usr/lib/libSystem.B.dylib"
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
func sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error) {
var _p0 unsafe.Pointer
if len(mib) > 0 {
diff --git a/src/syscall/zsyscall_darwin_arm64.s b/src/syscall/zsyscall_darwin_arm64.s
index 1666cf9..0567a42 100644
--- a/src/syscall/zsyscall_darwin_arm64.s
+++ b/src/syscall/zsyscall_darwin_arm64.s
@@ -219,16 +219,14 @@
JMP libc_mmap(SB)
TEXT ·libc_munmap_trampoline(SB),NOSPLIT,$0-0
JMP libc_munmap(SB)
-TEXT ·libc___fork_trampoline(SB),NOSPLIT,$0-0
- JMP libc___fork(SB)
+TEXT ·libc_fork_trampoline(SB),NOSPLIT,$0-0
+ JMP libc_fork(SB)
TEXT ·libc_ioctl_trampoline(SB),NOSPLIT,$0-0
JMP libc_ioctl(SB)
TEXT ·libc_execve_trampoline(SB),NOSPLIT,$0-0
JMP libc_execve(SB)
TEXT ·libc_exit_trampoline(SB),NOSPLIT,$0-0
JMP libc_exit(SB)
-TEXT ·libc___exit_trampoline(SB),NOSPLIT,$0-0
- JMP libc___exit(SB)
TEXT ·libc_sysctl_trampoline(SB),NOSPLIT,$0-0
JMP libc_sysctl(SB)
TEXT ·libc_unlinkat_trampoline(SB),NOSPLIT,$0-0
