syscall: reenable sysctl on iOS

This was disabled due to a report that the App Store rejects the symbol
__sysctl. However, we use the sysctl symbol, which is fine. The __sysctl
symbol is used by x/sys/unix, which needs fixing instead. So, this
commit reenables sysctl on iOS, so that things like net.InterfaceByName
can work again.

This reverts CL 193843, CL 193844, CL 193845, and CL 193846.

Fixes #35101
Updates #34133
Updates #35103

Change-Id: Ib8eb9f87b81db24965b0de29d99eb52887c7c60a
Reviewed-on: https://go-review.googlesource.com/c/go/+/202778
Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/log/syslog/syslog_test.go

@@ -134,9 +134,6 @@ func startServer(n, la string, done chan<- string) (addr string, sock io.Closer,
 }
 
 func TestWithSimulated(t *testing.T) {
-	if runtime.GOOS == "darwin" && (runtime.GOARCH == "arm" || runtime.GOARCH == "arm64") {
-		t.Skipf("sysctl is not supported on iOS")
-	}
 	t.Parallel()
 	msg := "Test 123"
 	var transport []string
@@ -275,9 +272,6 @@ func check(t *testing.T, in, out string) {
 }
 
 func TestWrite(t *testing.T) {
-	if runtime.GOOS == "darwin" && (runtime.GOARCH == "arm" || runtime.GOARCH == "arm64") {
-		t.Skipf("sysctl is not supported on iOS")
-	}
 	t.Parallel()
 	tests := []struct {
 		pri Priority

src/net/interface_test.go

@@ -50,18 +50,7 @@ func ipv6LinkLocalUnicastAddr(ifi *Interface) string {
 	return ""
 }
 
-func condSkipInterfaceTest(t *testing.T) {
-	t.Helper()
-	switch runtime.GOOS {
-	case "darwin":
-		if runtime.GOARCH == "arm" || runtime.GOARCH == "arm64" {
-			t.Skipf("sysctl is not supported on iOS")
-		}
-	}
-}
-
 func TestInterfaces(t *testing.T) {
-	condSkipInterfaceTest(t)
 	ift, err := Interfaces()
 	if err != nil {
 		t.Fatal(err)
@@ -93,7 +82,6 @@ func TestInterfaces(t *testing.T) {
 }
 
 func TestInterfaceAddrs(t *testing.T) {
-	condSkipInterfaceTest(t)
 	ift, err := Interfaces()
 	if err != nil {
 		t.Fatal(err)
@@ -113,7 +101,6 @@ func TestInterfaceAddrs(t *testing.T) {
 }
 
 func TestInterfaceUnicastAddrs(t *testing.T) {
-	condSkipInterfaceTest(t)
 	ift, err := Interfaces()
 	if err != nil {
 		t.Fatal(err)
@@ -141,7 +128,6 @@ func TestInterfaceUnicastAddrs(t *testing.T) {
 }
 
 func TestInterfaceMulticastAddrs(t *testing.T) {
-	condSkipInterfaceTest(t)
 	ift, err := Interfaces()
 	if err != nil {
 		t.Fatal(err)

src/os/os_test.go

@@ -1515,9 +1515,6 @@ func testWindowsHostname(t *testing.T, hostname string) {
 }
 
 func TestHostname(t *testing.T) {
-	if runtime.GOOS == "darwin" && (runtime.GOARCH == "arm" || runtime.GOARCH == "arm64") {
-		t.Skipf("sysctl is not supported on iOS")
-	}
 	hostname, err := Hostname()
 	if err != nil {
 		t.Fatal(err)

src/syscall/syscall_darwin.go

@@ -337,6 +337,7 @@ func Kill(pid int, signum Signal) (err error) { return kill(pid, int(signum), 1)
 //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)
+//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)
 //sys   openat(fd int, path string, flags int, perm uint32) (fdret int, err error)

src/syscall/syscall_darwin_386.go

@@ -22,7 +22,6 @@ func setTimeval(sec, usec int64) Timeval {
 //sys	Statfs(path string, stat *Statfs_t) (err error) = SYS_statfs64
 //sys   fstatat(fd int, path string, stat *Stat_t, flags int) (err error) = SYS_fstatat64
 //sys   ptrace(request int, pid int, addr uintptr, data uintptr) (err error)
-//sys   sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error)
 
 func SetKevent(k *Kevent_t, fd, mode, flags int) {
 	k.Ident = uint32(fd)

src/syscall/syscall_darwin_amd64.go

@@ -22,7 +22,6 @@ func setTimeval(sec, usec int64) Timeval {
 //sys	Statfs(path string, stat *Statfs_t) (err error) = SYS_statfs64
 //sys   fstatat(fd int, path string, stat *Stat_t, flags int) (err error) = SYS_fstatat64
 //sys   ptrace(request int, pid int, addr uintptr, data uintptr) (err error)
-//sys   sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error)
 
 func SetKevent(k *Kevent_t, fd, mode, flags int) {
 	k.Ident = uint64(fd)

src/syscall/syscall_darwin_arm.go

@@ -29,10 +29,6 @@ func ptrace(request int, pid int, addr uintptr, data uintptr) error {
 	return ENOTSUP
 }
 
-func sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) error {
-	return ENOTSUP
-}
-
 func SetKevent(k *Kevent_t, fd, mode, flags int) {
 	k.Ident = uint32(fd)
 	k.Filter = int16(mode)

src/syscall/syscall_darwin_arm64.go

@@ -29,10 +29,6 @@ func ptrace(request int, pid int, addr uintptr, data uintptr) error {
 	return ENOTSUP
 }
 
-func sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) error {
-	return ENOTSUP
-}
-
 func SetKevent(k *Kevent_t, fd, mode, flags int) {
 	k.Ident = uint64(fd)
 	k.Filter = int16(mode)

src/syscall/zsyscall_darwin_386.go

@@ -1870,6 +1870,27 @@ func libc_exit_trampoline()
 
 // 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 {
+		_p0 = unsafe.Pointer(&mib[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	_, _, e1 := syscall6(funcPC(libc_sysctl_trampoline), uintptr(_p0), uintptr(len(mib)), uintptr(unsafe.Pointer(old)), uintptr(unsafe.Pointer(oldlen)), uintptr(unsafe.Pointer(new)), uintptr(newlen))
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_sysctl_trampoline()
+
+//go:linkname libc_sysctl libc_sysctl
+//go:cgo_import_dynamic libc_sysctl sysctl "/usr/lib/libSystem.B.dylib"
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (val int, err error) {
 	r0, _, e1 := syscall(funcPC(libc_fcntl_trampoline), uintptr(fd), uintptr(cmd), uintptr(arg))
 	val = int(r0)
@@ -2060,24 +2081,3 @@ func libc_ptrace_trampoline()
 
 //go:linkname libc_ptrace libc_ptrace
 //go:cgo_import_dynamic libc_ptrace ptrace "/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 {
-		_p0 = unsafe.Pointer(&mib[0])
-	} else {
-		_p0 = unsafe.Pointer(&_zero)
-	}
-	_, _, e1 := syscall6(funcPC(libc_sysctl_trampoline), uintptr(_p0), uintptr(len(mib)), uintptr(unsafe.Pointer(old)), uintptr(unsafe.Pointer(oldlen)), uintptr(unsafe.Pointer(new)), uintptr(newlen))
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-func libc_sysctl_trampoline()
-
-//go:linkname libc_sysctl libc_sysctl
-//go:cgo_import_dynamic libc_sysctl sysctl "/usr/lib/libSystem.B.dylib"

src/syscall/zsyscall_darwin_386.s

@@ -229,6 +229,8 @@ 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_sysctl_trampoline(SB),NOSPLIT,$0-0
+	JMP	libc_sysctl(SB)
 TEXT ·libc_unlinkat_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_unlinkat(SB)
 TEXT ·libc_openat_trampoline(SB),NOSPLIT,$0-0
@@ -249,5 +251,3 @@ TEXT ·libc_fstatat64_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_fstatat64(SB)
 TEXT ·libc_ptrace_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_ptrace(SB)
-TEXT ·libc_sysctl_trampoline(SB),NOSPLIT,$0-0
-	JMP	libc_sysctl(SB)

src/syscall/zsyscall_darwin_amd64.go

@@ -1870,6 +1870,27 @@ func libc_exit_trampoline()
 
 // 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 {
+		_p0 = unsafe.Pointer(&mib[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	_, _, e1 := syscall6(funcPC(libc_sysctl_trampoline), uintptr(_p0), uintptr(len(mib)), uintptr(unsafe.Pointer(old)), uintptr(unsafe.Pointer(oldlen)), uintptr(unsafe.Pointer(new)), uintptr(newlen))
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_sysctl_trampoline()
+
+//go:linkname libc_sysctl libc_sysctl
+//go:cgo_import_dynamic libc_sysctl sysctl "/usr/lib/libSystem.B.dylib"
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (val int, err error) {
 	r0, _, e1 := syscall(funcPC(libc_fcntl_trampoline), uintptr(fd), uintptr(cmd), uintptr(arg))
 	val = int(r0)
@@ -2060,24 +2081,3 @@ func libc_ptrace_trampoline()
 
 //go:linkname libc_ptrace libc_ptrace
 //go:cgo_import_dynamic libc_ptrace ptrace "/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 {
-		_p0 = unsafe.Pointer(&mib[0])
-	} else {
-		_p0 = unsafe.Pointer(&_zero)
-	}
-	_, _, e1 := syscall6(funcPC(libc_sysctl_trampoline), uintptr(_p0), uintptr(len(mib)), uintptr(unsafe.Pointer(old)), uintptr(unsafe.Pointer(oldlen)), uintptr(unsafe.Pointer(new)), uintptr(newlen))
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-func libc_sysctl_trampoline()
-
-//go:linkname libc_sysctl libc_sysctl
-//go:cgo_import_dynamic libc_sysctl sysctl "/usr/lib/libSystem.B.dylib"

src/syscall/zsyscall_darwin_amd64.s

@@ -229,6 +229,8 @@ 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_sysctl_trampoline(SB),NOSPLIT,$0-0
+	JMP	libc_sysctl(SB)
 TEXT ·libc_unlinkat_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_unlinkat(SB)
 TEXT ·libc_openat_trampoline(SB),NOSPLIT,$0-0
@@ -249,5 +251,3 @@ TEXT ·libc_fstatat64_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_fstatat64(SB)
 TEXT ·libc_ptrace_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_ptrace(SB)
-TEXT ·libc_sysctl_trampoline(SB),NOSPLIT,$0-0
-	JMP	libc_sysctl(SB)

src/syscall/zsyscall_darwin_arm.go

@@ -1870,6 +1870,27 @@ func libc_exit_trampoline()
 
 // 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 {
+		_p0 = unsafe.Pointer(&mib[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	_, _, e1 := syscall6(funcPC(libc_sysctl_trampoline), uintptr(_p0), uintptr(len(mib)), uintptr(unsafe.Pointer(old)), uintptr(unsafe.Pointer(oldlen)), uintptr(unsafe.Pointer(new)), uintptr(newlen))
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_sysctl_trampoline()
+
+//go:linkname libc_sysctl libc_sysctl
+//go:cgo_import_dynamic libc_sysctl sysctl "/usr/lib/libSystem.B.dylib"
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (val int, err error) {
 	r0, _, e1 := syscall(funcPC(libc_fcntl_trampoline), uintptr(fd), uintptr(cmd), uintptr(arg))
 	val = int(r0)

src/syscall/zsyscall_darwin_arm.s

@@ -229,6 +229,8 @@ 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_sysctl_trampoline(SB),NOSPLIT,$0-0
+	JMP	libc_sysctl(SB)
 TEXT ·libc_unlinkat_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_unlinkat(SB)
 TEXT ·libc_openat_trampoline(SB),NOSPLIT,$0-0

src/syscall/zsyscall_darwin_arm64.go

@@ -1870,6 +1870,27 @@ func libc_exit_trampoline()
 
 // 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 {
+		_p0 = unsafe.Pointer(&mib[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	_, _, e1 := syscall6(funcPC(libc_sysctl_trampoline), uintptr(_p0), uintptr(len(mib)), uintptr(unsafe.Pointer(old)), uintptr(unsafe.Pointer(oldlen)), uintptr(unsafe.Pointer(new)), uintptr(newlen))
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_sysctl_trampoline()
+
+//go:linkname libc_sysctl libc_sysctl
+//go:cgo_import_dynamic libc_sysctl sysctl "/usr/lib/libSystem.B.dylib"
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (val int, err error) {
 	r0, _, e1 := syscall(funcPC(libc_fcntl_trampoline), uintptr(fd), uintptr(cmd), uintptr(arg))
 	val = int(r0)

src/syscall/zsyscall_darwin_arm64.s

@@ -229,6 +229,8 @@ 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_sysctl_trampoline(SB),NOSPLIT,$0-0
+	JMP	libc_sysctl(SB)
 TEXT ·libc_unlinkat_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_unlinkat(SB)
 TEXT ·libc_openat_trampoline(SB),NOSPLIT,$0-0