syscall: only compile ptrace varargs shim on Linux

Only compile the __go_ptrace varargs shim on Linux to avoid compilation
failures on some other platforms. The C ptrace function is not entirely
portable (e.g., NetBSD has `int data` instead of `void* data`), and so
far Linux is the only platform that needs the varargs shim.

Additionally, make the types in the ptrace and raw_ptrace function
declarations match. This makes it more clear that the only difference
between the two is that calls via the former are allowed to block while
calls via the latter are not.

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/263517

13 files changed, 17 insertions, 18 deletions

diff --git a/libgo/go/syscall/exec_bsd.go b/libgo/go/syscall/exec_bsd.go
index 7e06943f13e..ca7fdc0825e 100644
--- a/libgo/go/syscall/exec_bsd.go
+++ b/libgo/go/syscall/exec_bsd.go
@@ -93,7 +93,7 @@ func forkAndExecInChild(argv0 *byte, argv, envv []*byte, chroot, dir *byte, attr
 
 	// Enable tracing if requested.
 	if sys.Ptrace {
-		err1 = raw_ptrace(_PTRACE_TRACEME, 0, nil, nil)
+		err1 = raw_ptrace(_PTRACE_TRACEME, 0, 0, 0)
 		if err1 != 0 {
 			goto childerror
 		}
diff --git a/libgo/go/syscall/exec_linux.go b/libgo/go/syscall/exec_linux.go
index 2f0a34fef0b..38975810432 100644
--- a/libgo/go/syscall/exec_linux.go
+++ b/libgo/go/syscall/exec_linux.go
@@ -538,7 +538,7 @@ func forkAndExecInChild1(argv0 *byte, argv, envv []*byte, chroot, dir *byte, att
 	// Do this right before exec so that we don't unnecessarily trace the runtime
 	// setting up after the fork. See issue #21428.
 	if sys.Ptrace {
-		err1 = raw_ptrace(_PTRACE_TRACEME, 0, nil, nil)
+		err1 = raw_ptrace(_PTRACE_TRACEME, 0, 0, 0)
 		if err1 != 0 {
 			goto childerror
 		}
diff --git a/libgo/go/syscall/exec_stubs.go b/libgo/go/syscall/exec_stubs.go
index e95b4158e1a..c837cf7a4e2 100644
--- a/libgo/go/syscall/exec_stubs.go
+++ b/libgo/go/syscall/exec_stubs.go
@@ -30,6 +30,6 @@ func (w WaitStatus) Signal() int     { return 0 }
 func (w WaitStatus) StopSignal() int { return 0 }
 func (w WaitStatus) TrapCause() int  { return 0 }
 
-func raw_ptrace(request int, pid int, addr *byte, data *byte) Errno {
+func raw_ptrace(request int, pid int, addr uintptr, data uintptr) Errno {
 	return ENOSYS
 }
diff --git a/libgo/go/syscall/libcall_aix.go b/libgo/go/syscall/libcall_aix.go
index 27b469e1e47..92c7f3cc232 100644
--- a/libgo/go/syscall/libcall_aix.go
+++ b/libgo/go/syscall/libcall_aix.go
@@ -19,7 +19,7 @@ const SYS_EXECVE = 0
 //sys	ptrace64(request int, id int64, addr int64, data int, buff uintptr) (err error)
 //ptrace64(request _C_int, id int64, addr int64, data _C_int, buff *byte) _C_int
 
-func raw_ptrace(request int, pid int, addr *byte, data *byte) Errno {
+func raw_ptrace(request int, pid int, addr uintptr, data uintptr) Errno {
 	if request == _PTRACE_TRACEME {
 		// Convert to AIX ptrace call.
 		err := ptrace64(_PT_TRACE_ME, 0, 0, 0, 0)
diff --git a/libgo/go/syscall/libcall_glibc.go b/libgo/go/syscall/libcall_glibc.go
index 823343d5075..a32d6968f24 100644
--- a/libgo/go/syscall/libcall_glibc.go
+++ b/libgo/go/syscall/libcall_glibc.go
@@ -31,9 +31,6 @@ func Futimes(fd int, tv []Timeval) (err error) {
 	return Utimes("/proc/self/fd/"+itoa(fd), tv)
 }
 
-//sys	ptrace(request int, pid int, addr uintptr, data uintptr) (err error)
-//__go_ptrace(request _C_int, pid Pid_t, addr *byte, data *byte) _C_long
-
 //sys	accept4(fd int, sa *RawSockaddrAny, len *Socklen_t, flags int) (nfd int, err error)
 //accept4(fd _C_int, sa *RawSockaddrAny, len *Socklen_t, flags _C_int) _C_int
 
diff --git a/libgo/go/syscall/libcall_hurd.go b/libgo/go/syscall/libcall_hurd.go
index f0e038ca616..44ff46d1016 100644
--- a/libgo/go/syscall/libcall_hurd.go
+++ b/libgo/go/syscall/libcall_hurd.go
@@ -7,7 +7,7 @@
 package syscall
 
 // Dummy function
-func raw_ptrace(request int, pid int, addr *byte, data *byte) Errno {
+func raw_ptrace(request int, pid int, addr uintptr, data uintptr) Errno {
 	return ENOSYS
 }
 
diff --git a/libgo/go/syscall/libcall_irix.go b/libgo/go/syscall/libcall_irix.go
index 9b6cdcca2c8..98807668d52 100644
--- a/libgo/go/syscall/libcall_irix.go
+++ b/libgo/go/syscall/libcall_irix.go
@@ -6,5 +6,5 @@
 
 package syscall
 
-//sysnb raw_ptrace(request int, pid int, addr *byte, data *byte) (err Errno)
+//sysnb raw_ptrace(request int, pid int, addr uintptr, data uintptr) (err Errno)
 //ptrace(request _C_int, pid Pid_t, addr *byte, data *byte) _C_long
diff --git a/libgo/go/syscall/libcall_linux.go b/libgo/go/syscall/libcall_linux.go
index 78fda0ea7ef..96974bd3269 100644
--- a/libgo/go/syscall/libcall_linux.go
+++ b/libgo/go/syscall/libcall_linux.go
@@ -10,7 +10,10 @@ import (
 	"unsafe"
 )
 
-//sysnb raw_ptrace(request int, pid int, addr *byte, data *byte) (err Errno)
+//sys	ptrace(request int, pid int, addr uintptr, data uintptr) (err Errno)
+//__go_ptrace(request _C_int, pid Pid_t, addr *byte, data *byte) _C_long
+
+//sysnb raw_ptrace(request int, pid int, addr uintptr, data uintptr) (err Errno)
 //__go_ptrace(request _C_int, pid Pid_t, addr *byte, data *byte) _C_long
 
 func ptracePeek(req int, pid int, addr uintptr, out []byte) (count int, err error) {
diff --git a/libgo/go/syscall/libcall_solaris_386.go b/libgo/go/syscall/libcall_solaris_386.go
index 20eba22a302..ef86f09711d 100644
--- a/libgo/go/syscall/libcall_solaris_386.go
+++ b/libgo/go/syscall/libcall_solaris_386.go
@@ -8,5 +8,5 @@ package syscall
 //sysnb	Uname(buf *Utsname) (err error)
 //_nuname(buf *Utsname) _C_int
 
-//sysnb raw_ptrace(request int, pid int, addr *byte, data *byte) (err Errno)
+//sysnb raw_ptrace(request int, pid int, addr uintptr, data uintptr) (err Errno)
 //ptrace(request _C_int, pid Pid_t, addr *byte, data *byte) _C_long
diff --git a/libgo/go/syscall/libcall_solaris_amd64.go b/libgo/go/syscall/libcall_solaris_amd64.go
index 69b11ba5ee6..f44025e1eec 100644
--- a/libgo/go/syscall/libcall_solaris_amd64.go
+++ b/libgo/go/syscall/libcall_solaris_amd64.go
@@ -5,6 +5,6 @@
 package syscall
 
 // 64-bit ptrace(3C) doesn't exist
-func raw_ptrace(request int, pid int, addr *byte, data *byte) Errno {
+func raw_ptrace(request int, pid int, addr uintptr, data uintptr) Errno {
 	return ENOSYS
 }
diff --git a/libgo/go/syscall/libcall_solaris_sparc.go b/libgo/go/syscall/libcall_solaris_sparc.go
index 50863fadf18..3d50309983f 100644
--- a/libgo/go/syscall/libcall_solaris_sparc.go
+++ b/libgo/go/syscall/libcall_solaris_sparc.go
@@ -4,5 +4,5 @@
 
 package syscall
 
-//sysnb raw_ptrace(request int, pid int, addr *byte, data *byte) (err Errno)
+//sysnb raw_ptrace(request int, pid int, addr uintptr, data uintptr) (err Errno)
 //ptrace(request _C_int, pid Pid_t, addr *byte, data *byte) _C_long
diff --git a/libgo/go/syscall/libcall_solaris_sparc64.go b/libgo/go/syscall/libcall_solaris_sparc64.go
index 69b11ba5ee6..f44025e1eec 100644
--- a/libgo/go/syscall/libcall_solaris_sparc64.go
+++ b/libgo/go/syscall/libcall_solaris_sparc64.go
@@ -5,6 +5,6 @@
 package syscall
 
 // 64-bit ptrace(3C) doesn't exist
-func raw_ptrace(request int, pid int, addr *byte, data *byte) Errno {
+func raw_ptrace(request int, pid int, addr uintptr, data uintptr) Errno {
 	return ENOSYS
 }
diff --git a/libgo/runtime/go-varargs.c b/libgo/runtime/go-varargs.c
index d8f7dc55ea4..f84860891e6 100644
--- a/libgo/runtime/go-varargs.c
+++ b/libgo/runtime/go-varargs.c
@@ -114,12 +114,11 @@ __go_syscall6(uintptr_t flag, uintptr_t a1, uintptr_t a2, uintptr_t a3,
 
 #endif
 
-// AIX ptrace is really different from Linux ptrace. Let syscall
-// package handles it.
-#if defined(HAVE_SYS_PTRACE_H) && !defined(_AIX)
+
+#if defined(HAVE_SYS_PTRACE_H) && defined(__linux__)
 
 // Despite documented appearances, this is actually implemented as
-// a variadic function within glibc.
+// a variadic function within glibc on Linux.
 
 long
 __go_ptrace(int request, pid_t pid, void *addr, void *data)