internal/syscall/unix: use libc calls on Darwin

Add unexported unlinkat, openat, and fstatat calls, so that
the internal/syscall/unix package can use them.

Change-Id: I1df81ecae6427211dd392ec68c9f020fe131a526
Reviewed-on: https://go-review.googlesource.com/c/148457
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/internal/syscall/unix/at.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build linux darwin openbsd netbsd dragonfly
+// +build linux openbsd netbsd dragonfly
 
 package unix
 

src/internal/syscall/unix/at_darwin.go

@@ -0,0 +1,31 @@
+// Copyright 2018 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 unix
+
+import (
+	"syscall"
+	_ "unsafe" // for linkname
+)
+
+func Unlinkat(dirfd int, path string, flags int) error {
+	return unlinkat(dirfd, path, flags)
+}
+
+func Openat(dirfd int, path string, flags int, perm uint32) (int, error) {
+	return openat(dirfd, path, flags, perm)
+}
+
+func Fstatat(dirfd int, path string, stat *syscall.Stat_t, flags int) error {
+	return fstatat(dirfd, path, stat, flags)
+}
+
+//go:linkname unlinkat syscall.unlinkat
+func unlinkat(dirfd int, path string, flags int) error
+
+//go:linkname openat syscall.openat
+func openat(dirfd int, path string, flags int, perm uint32) (int, error)
+
+//go:linkname fstatat syscall.fstatat
+func fstatat(dirfd int, path string, stat *syscall.Stat_t, flags int) error

src/runtime/sys_darwin_arm64.s

@@ -483,7 +483,7 @@ ok:
 // C calling convention (use libcCall).
 TEXT runtime·syscall6(SB),NOSPLIT,$0
 	SUB	$16, RSP	// push structure pointer
-	MOVD	R0, (RSP)
+	MOVD	R0, 8(RSP)
 
 	MOVD	0(R0), R12	// fn
 	MOVD	16(R0), R1	// a2
@@ -492,19 +492,25 @@ TEXT runtime·syscall6(SB),NOSPLIT,$0
 	MOVD	40(R0), R4	// a5
 	MOVD	48(R0), R5	// a6
 	MOVD	8(R0), R0	// a1
+
+	// If fn is declared as vararg, we have to pass the vararg arguments on the stack.
+	// See syscall above. The only function this applies to is openat, for which the 4th
+	// arg must be on the stack.
+	MOVD	R3, (RSP)
+
 	BL	(R12)
 
-	MOVD	(RSP), R2	// pop structure pointer
+	MOVD	8(RSP), R2	// pop structure pointer
 	ADD	$16, RSP
 	MOVD	R0, 56(R2)	// save r1
 	MOVD	R1, 64(R2)	// save r2
 	CMPW	$-1, R0
 	BNE	ok
 	SUB	$16, RSP	// push structure pointer
-	MOVD	R2, (RSP)
+	MOVD	R2, 8(RSP)
 	BL	libc_error(SB)
 	MOVW	(R0), R0
-	MOVD	(RSP), R2	// pop structure pointer
+	MOVD	8(RSP), R2	// pop structure pointer
 	ADD	$16, RSP
 	MOVD	R0, 72(R2)	// save err
 ok:

src/syscall/syscall_darwin.go

@@ -344,6 +344,9 @@ func Kill(pid int, signum Signal) (err error) { return kill(pid, int(signum), 1)
 //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)
+//sys   fstatat(fd int, path string, stat *Stat_t, flags int) (err error) = SYS_fstatat64
 
 func init() {
 	execveDarwin = execve

src/syscall/zsyscall_darwin_386.go

@@ -1886,6 +1886,64 @@ func fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (val int, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func unlinkat(fd int, path string, flags int) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	_, _, e1 := syscall(funcPC(libc_unlinkat_trampoline), uintptr(fd), uintptr(unsafe.Pointer(_p0)), uintptr(flags))
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_unlinkat_trampoline()
+
+//go:linkname libc_unlinkat libc_unlinkat
+//go:cgo_import_dynamic libc_unlinkat unlinkat "/usr/lib/libSystem.B.dylib"
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func openat(fd int, path string, flags int, perm uint32) (fdret int, err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	r0, _, e1 := syscall6(funcPC(libc_openat_trampoline), uintptr(fd), uintptr(unsafe.Pointer(_p0)), uintptr(flags), uintptr(perm), 0, 0)
+	fdret = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_openat_trampoline()
+
+//go:linkname libc_openat libc_openat
+//go:cgo_import_dynamic libc_openat openat "/usr/lib/libSystem.B.dylib"
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func fstatat(fd int, path string, stat *Stat_t, flags int) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	_, _, e1 := syscall6(funcPC(libc_fstatat64_trampoline), uintptr(fd), uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), uintptr(flags), 0, 0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_fstatat64_trampoline()
+
+//go:linkname libc_fstatat64 libc_fstatat64
+//go:cgo_import_dynamic libc_fstatat64 fstatat64 "/usr/lib/libSystem.B.dylib"
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Gettimeofday(tp *Timeval) (err error) {
 	_, _, e1 := rawSyscall(funcPC(libc_gettimeofday_trampoline), uintptr(unsafe.Pointer(tp)), 0, 0)
 	if e1 != 0 {

src/syscall/zsyscall_darwin_386.s

@@ -239,5 +239,11 @@ 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
+	JMP	libc_openat(SB)
+TEXT ·libc_fstatat64_trampoline(SB),NOSPLIT,$0-0
+	JMP	libc_fstatat64(SB)
 TEXT ·libc_gettimeofday_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_gettimeofday(SB)

src/syscall/zsyscall_darwin_amd64.go

@@ -1886,6 +1886,64 @@ func fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (val int, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func unlinkat(fd int, path string, flags int) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	_, _, e1 := syscall(funcPC(libc_unlinkat_trampoline), uintptr(fd), uintptr(unsafe.Pointer(_p0)), uintptr(flags))
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_unlinkat_trampoline()
+
+//go:linkname libc_unlinkat libc_unlinkat
+//go:cgo_import_dynamic libc_unlinkat unlinkat "/usr/lib/libSystem.B.dylib"
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func openat(fd int, path string, flags int, perm uint32) (fdret int, err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	r0, _, e1 := syscall6(funcPC(libc_openat_trampoline), uintptr(fd), uintptr(unsafe.Pointer(_p0)), uintptr(flags), uintptr(perm), 0, 0)
+	fdret = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_openat_trampoline()
+
+//go:linkname libc_openat libc_openat
+//go:cgo_import_dynamic libc_openat openat "/usr/lib/libSystem.B.dylib"
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func fstatat(fd int, path string, stat *Stat_t, flags int) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	_, _, e1 := syscall6(funcPC(libc_fstatat64_trampoline), uintptr(fd), uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), uintptr(flags), 0, 0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_fstatat64_trampoline()
+
+//go:linkname libc_fstatat64 libc_fstatat64
+//go:cgo_import_dynamic libc_fstatat64 fstatat64 "/usr/lib/libSystem.B.dylib"
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Gettimeofday(tp *Timeval) (err error) {
 	_, _, e1 := rawSyscall(funcPC(libc_gettimeofday_trampoline), uintptr(unsafe.Pointer(tp)), 0, 0)
 	if e1 != 0 {

src/syscall/zsyscall_darwin_amd64.s

@@ -239,5 +239,11 @@ 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
+	JMP	libc_openat(SB)
+TEXT ·libc_fstatat64_trampoline(SB),NOSPLIT,$0-0
+	JMP	libc_fstatat64(SB)
 TEXT ·libc_gettimeofday_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_gettimeofday(SB)

src/syscall/zsyscall_darwin_arm.go

@@ -1886,6 +1886,64 @@ func fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (val int, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func unlinkat(fd int, path string, flags int) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	_, _, e1 := syscall(funcPC(libc_unlinkat_trampoline), uintptr(fd), uintptr(unsafe.Pointer(_p0)), uintptr(flags))
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_unlinkat_trampoline()
+
+//go:linkname libc_unlinkat libc_unlinkat
+//go:cgo_import_dynamic libc_unlinkat unlinkat "/usr/lib/libSystem.B.dylib"
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func openat(fd int, path string, flags int, perm uint32) (fdret int, err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	r0, _, e1 := syscall6(funcPC(libc_openat_trampoline), uintptr(fd), uintptr(unsafe.Pointer(_p0)), uintptr(flags), uintptr(perm), 0, 0)
+	fdret = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_openat_trampoline()
+
+//go:linkname libc_openat libc_openat
+//go:cgo_import_dynamic libc_openat openat "/usr/lib/libSystem.B.dylib"
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func fstatat(fd int, path string, stat *Stat_t, flags int) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	_, _, e1 := syscall6(funcPC(libc_fstatat64_trampoline), uintptr(fd), uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), uintptr(flags), 0, 0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_fstatat64_trampoline()
+
+//go:linkname libc_fstatat64 libc_fstatat64
+//go:cgo_import_dynamic libc_fstatat64 fstatat64 "/usr/lib/libSystem.B.dylib"
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Gettimeofday(tp *Timeval) (err error) {
 	_, _, e1 := rawSyscall(funcPC(libc_gettimeofday_trampoline), uintptr(unsafe.Pointer(tp)), 0, 0)
 	if e1 != 0 {

src/syscall/zsyscall_darwin_arm.s

@@ -223,6 +223,8 @@ TEXT ·libc_unmount_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_unmount(SB)
 TEXT ·libc_write_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_write(SB)
+TEXT ·libc_writev_trampoline(SB),NOSPLIT,$0-0
+	JMP	libc_writev(SB)
 TEXT ·libc_mmap_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_mmap(SB)
 TEXT ·libc_munmap_trampoline(SB),NOSPLIT,$0-0
@@ -237,7 +239,11 @@ 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_writev_trampoline(SB),NOSPLIT,$0-0
+TEXT ·libc_unlinkat_trampoline(SB),NOSPLIT,$0-0
-	JMP	libc_writev(SB)
+	JMP	libc_unlinkat(SB)
+TEXT ·libc_openat_trampoline(SB),NOSPLIT,$0-0
+	JMP	libc_openat(SB)
+TEXT ·libc_fstatat64_trampoline(SB),NOSPLIT,$0-0
+	JMP	libc_fstatat64(SB)
 TEXT ·libc_gettimeofday_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_gettimeofday(SB)

src/syscall/zsyscall_darwin_arm64.go

@@ -1886,6 +1886,64 @@ func fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (val int, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func unlinkat(fd int, path string, flags int) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	_, _, e1 := syscall(funcPC(libc_unlinkat_trampoline), uintptr(fd), uintptr(unsafe.Pointer(_p0)), uintptr(flags))
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_unlinkat_trampoline()
+
+//go:linkname libc_unlinkat libc_unlinkat
+//go:cgo_import_dynamic libc_unlinkat unlinkat "/usr/lib/libSystem.B.dylib"
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func openat(fd int, path string, flags int, perm uint32) (fdret int, err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	r0, _, e1 := syscall6(funcPC(libc_openat_trampoline), uintptr(fd), uintptr(unsafe.Pointer(_p0)), uintptr(flags), uintptr(perm), 0, 0)
+	fdret = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_openat_trampoline()
+
+//go:linkname libc_openat libc_openat
+//go:cgo_import_dynamic libc_openat openat "/usr/lib/libSystem.B.dylib"
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func fstatat(fd int, path string, stat *Stat_t, flags int) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	_, _, e1 := syscall6(funcPC(libc_fstatat64_trampoline), uintptr(fd), uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), uintptr(flags), 0, 0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_fstatat64_trampoline()
+
+//go:linkname libc_fstatat64 libc_fstatat64
+//go:cgo_import_dynamic libc_fstatat64 fstatat64 "/usr/lib/libSystem.B.dylib"
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Gettimeofday(tp *Timeval) (err error) {
 	_, _, e1 := rawSyscall(funcPC(libc_gettimeofday_trampoline), uintptr(unsafe.Pointer(tp)), 0, 0)
 	if e1 != 0 {

src/syscall/zsyscall_darwin_arm64.s

@@ -223,6 +223,8 @@ TEXT ·libc_unmount_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_unmount(SB)
 TEXT ·libc_write_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_write(SB)
+TEXT ·libc_writev_trampoline(SB),NOSPLIT,$0-0
+	JMP	libc_writev(SB)
 TEXT ·libc_mmap_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_mmap(SB)
 TEXT ·libc_munmap_trampoline(SB),NOSPLIT,$0-0
@@ -237,7 +239,11 @@ 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_writev_trampoline(SB),NOSPLIT,$0-0
+TEXT ·libc_unlinkat_trampoline(SB),NOSPLIT,$0-0
-	JMP	libc_writev(SB)
+	JMP	libc_unlinkat(SB)
+TEXT ·libc_openat_trampoline(SB),NOSPLIT,$0-0
+	JMP	libc_openat(SB)
+TEXT ·libc_fstatat64_trampoline(SB),NOSPLIT,$0-0
+	JMP	libc_fstatat64(SB)
 TEXT ·libc_gettimeofday_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_gettimeofday(SB)