[release-branch.go1.13] 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 #35105
Updates #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>
Reviewed-on: https://go-review.googlesource.com/c/go/+/202779
Reviewed-by: Elias Naur <mail@eliasnaur.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

16 files changed, 93 insertions, 77 deletions

diff --git a/src/log/syslog/syslog_test.go b/src/log/syslog/syslog_test.go
index 8a28d67c98..447654a874 100644
--- a/src/log/syslog/syslog_test.go
+++ b/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
diff --git a/src/net/interface_test.go b/src/net/interface_test.go
index 6cdfb6265f..fb6032fbc0 100644
--- a/src/net/interface_test.go
+++ b/src/net/interface_test.go
@@ -51,9 +51,6 @@ func ipv6LinkLocalUnicastAddr(ifi *Interface) string {
 }
 
 func TestInterfaces(t *testing.T) {
-	if runtime.GOOS == "darwin" && (runtime.GOARCH == "arm" || runtime.GOARCH == "arm64") {
-		t.Skipf("sysctl is not supported on iOS")
-	}
 	ift, err := Interfaces()
 	if err != nil {
 		t.Fatal(err)
@@ -85,9 +82,6 @@ func TestInterfaces(t *testing.T) {
 }
 
 func TestInterfaceAddrs(t *testing.T) {
-	if runtime.GOOS == "darwin" && (runtime.GOARCH == "arm" || runtime.GOARCH == "arm64") {
-		t.Skipf("sysctl is not supported on iOS")
-	}
 	ift, err := Interfaces()
 	if err != nil {
 		t.Fatal(err)
@@ -107,9 +101,6 @@ func TestInterfaceAddrs(t *testing.T) {
 }
 
 func TestInterfaceUnicastAddrs(t *testing.T) {
-	if runtime.GOOS == "darwin" && (runtime.GOARCH == "arm" || runtime.GOARCH == "arm64") {
-		t.Skipf("sysctl is not supported on iOS")
-	}
 	ift, err := Interfaces()
 	if err != nil {
 		t.Fatal(err)
@@ -137,9 +128,6 @@ func TestInterfaceUnicastAddrs(t *testing.T) {
 }
 
 func TestInterfaceMulticastAddrs(t *testing.T) {
-	if runtime.GOOS == "darwin" && (runtime.GOARCH == "arm" || runtime.GOARCH == "arm64") {
-		t.Skipf("sysctl is not supported on iOS")
-	}
 	ift, err := Interfaces()
 	if err != nil {
 		t.Fatal(err)
diff --git a/src/os/os_test.go b/src/os/os_test.go
index b94ab0d232..c101281258 100644
--- a/src/os/os_test.go
+++ b/src/os/os_test.go
@@ -1521,9 +1521,6 @@ 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)
diff --git a/src/syscall/syscall_darwin.go b/src/syscall/syscall_darwin.go
index 2efcf3bea9..7d795ee4d3 100644
--- a/src/syscall/syscall_darwin.go
+++ b/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)
diff --git a/src/syscall/syscall_darwin_386.go b/src/syscall/syscall_darwin_386.go
index 46714bab57..8c5b82da55 100644
--- a/src/syscall/syscall_darwin_386.go
+++ b/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)
diff --git a/src/syscall/syscall_darwin_amd64.go b/src/syscall/syscall_darwin_amd64.go
index 43506e4531..23a4e5f996 100644
--- a/src/syscall/syscall_darwin_amd64.go
+++ b/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)
diff --git a/src/syscall/syscall_darwin_arm.go b/src/syscall/syscall_darwin_arm.go
index 4ca2e300e4..7f39cf4003 100644
--- a/src/syscall/syscall_darwin_arm.go
+++ b/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)
diff --git a/src/syscall/syscall_darwin_arm64.go b/src/syscall/syscall_darwin_arm64.go
index fde48f3596..bd110f2e7f 100644
--- a/src/syscall/syscall_darwin_arm64.go
+++ b/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)
diff --git a/src/syscall/zsyscall_darwin_386.go b/src/syscall/zsyscall_darwin_386.go
index 0ffc692116..2c3b15f5f9 100644
--- a/src/syscall/zsyscall_darwin_386.go
+++ b/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"
diff --git a/src/syscall/zsyscall_darwin_386.s b/src/syscall/zsyscall_darwin_386.s
index 0dec5baa22..d84b46229e 100644
--- a/src/syscall/zsyscall_darwin_386.s
+++ b/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)
diff --git a/src/syscall/zsyscall_darwin_amd64.go b/src/syscall/zsyscall_darwin_amd64.go
index 942152ae39..83214de2fb 100644
--- a/src/syscall/zsyscall_darwin_amd64.go
+++ b/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"
diff --git a/src/syscall/zsyscall_darwin_amd64.s b/src/syscall/zsyscall_darwin_amd64.s
index fcb7f9c291..23ddbe06c0 100644
--- a/src/syscall/zsyscall_darwin_amd64.s
+++ b/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)
diff --git a/src/syscall/zsyscall_darwin_arm.go b/src/syscall/zsyscall_darwin_arm.go
index 73ee205d33..2a643f209f 100644
--- a/src/syscall/zsyscall_darwin_arm.go
+++ b/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)
diff --git a/src/syscall/zsyscall_darwin_arm.s b/src/syscall/zsyscall_darwin_arm.s
index 6462a198b0..c7cd83d83e 100644
--- a/src/syscall/zsyscall_darwin_arm.s
+++ b/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
diff --git a/src/syscall/zsyscall_darwin_arm64.go b/src/syscall/zsyscall_darwin_arm64.go
index bbe092cd07..0b77839869 100644
--- a/src/syscall/zsyscall_darwin_arm64.go
+++ b/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)
diff --git a/src/syscall/zsyscall_darwin_arm64.s b/src/syscall/zsyscall_darwin_arm64.s
index ec2210f1df..7b8b3764a8 100644
--- a/src/syscall/zsyscall_darwin_arm64.s
+++ b/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