unix: fix EpollWait for arm64

epoll_wait syscall doesn't exist on arm64. Implement it with
by callign epoll_pwait(). According to man epoll_pwait,
calling epoll_pwait with sigmask of NULL is identical to
epoll_wait.

Testing exposed that EpollEvent needs padding on arm64
like on arm.

This changeset is to fix:
https://github.com/fsnotify/fsnotify/issues/130

Testcase: go test with fsnotify ported from syscall to x/sys:
https://github.com/suihkulokki/fsnotify/tree/go-sys

Change-Id: I76136bf4c82c2ee597549133848f490da46dd488
Reviewed-on: https://go-review.googlesource.com/21971
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

unix/syscall_linux.go

@@ -872,7 +872,6 @@ func Mount(source string, target string, fstype string, flags uintptr, data stri
 //sysnb	EpollCreate(size int) (fd int, err error)
 //sysnb	EpollCreate1(flag int) (fd int, err error)
 //sysnb	EpollCtl(epfd int, op int, fd int, event *EpollEvent) (err error)
-//sys	EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
 //sys	Exit(code int) = SYS_EXIT_GROUP
 //sys	Faccessat(dirfd int, path string, mode uint32, flags int) (err error)
 //sys	Fallocate(fd int, mode uint32, off int64, len int64) (err error)

unix/syscall_linux_386.go

@@ -91,6 +91,7 @@ func Pipe2(p []int, flags int) (err error) {
 //sys	Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error) = SYS__NEWSELECT
 
 //sys	mmap2(addr uintptr, length uintptr, prot int, flags int, fd int, pageOffset uintptr) (xaddr uintptr, err error)
+//sys	EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
 
 func mmap(addr uintptr, length uintptr, prot int, flags int, fd int, offset int64) (xaddr uintptr, err error) {
 	page := uintptr(offset / 4096)

unix/syscall_linux_amd64.go

@@ -9,6 +9,7 @@ package unix
 import "syscall"
 
 //sys	Dup2(oldfd int, newfd int) (err error)
+//sys	EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
 //sys	Fadvise(fd int, offset int64, length int64, advice int) (err error) = SYS_FADVISE64
 //sys	Fchown(fd int, uid int, gid int) (err error)
 //sys	Fstat(fd int, stat *Stat_t) (err error)

unix/syscall_linux_arm.go

@@ -108,6 +108,7 @@ func Seek(fd int, offset int64, whence int) (newoffset int64, err error) {
 
 // Vsyscalls on amd64.
 //sysnb	Gettimeofday(tv *Timeval) (err error)
+//sys	EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
 
 func Time(t *Time_t) (Time_t, error) {
 	var tv Timeval

unix/syscall_linux_arm64.go

@@ -8,6 +8,7 @@ package unix
 
 const _SYS_dup = SYS_DUP3
 
+//sys	EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) = SYS_EPOLL_PWAIT
 //sys	Fchown(fd int, uid int, gid int) (err error)
 //sys	Fstat(fd int, stat *Stat_t) (err error)
 //sys	Fstatat(fd int, path string, stat *Stat_t, flags int) (err error)

unix/syscall_linux_mips64x.go

@@ -14,6 +14,7 @@ package unix
 // Lookup linux_dirent{,64} in kernel source code for details.
 const _SYS_getdents = SYS_GETDENTS
 
+//sys	EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
 //sys	Fchown(fd int, uid int, gid int) (err error)
 //sys	Fstatfs(fd int, buf *Statfs_t) (err error)
 //sys	Ftruncate(fd int, length int64) (err error)

unix/syscall_linux_ppc64x.go

@@ -7,6 +7,7 @@
 
 package unix
 
+//sys	EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
 //sys	Dup2(oldfd int, newfd int) (err error)
 //sys	Fchown(fd int, uid int, gid int) (err error)
 //sys	Fstat(fd int, stat *Stat_t) (err error)

unix/types_linux.go

@@ -109,7 +109,7 @@ typedef struct user_regs_struct PtraceRegs;
 // The real epoll_event is a union, and godefs doesn't handle it well.
 struct my_epoll_event {
 	uint32_t events;
-#ifdef __ARM_EABI__
+#if defined(__ARM_EABI__) || defined(__aarch64__)
 	// padding is not specified in linux/eventpoll.h but added to conform to the
 	// alignment requirements of EABI
 	int32_t padFd;

unix/zsyscall_linux_386.go

@@ -370,23 +370,6 @@ func EpollCtl(epfd int, op int, fd int, event *EpollEvent) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
-	var _p0 unsafe.Pointer
-	if len(events) > 0 {
-		_p0 = unsafe.Pointer(&events[0])
-	} else {
-		_p0 = unsafe.Pointer(&_zero)
-	}
-	r0, _, e1 := Syscall6(SYS_EPOLL_WAIT, uintptr(epfd), uintptr(_p0), uintptr(len(events)), uintptr(msec), 0, 0)
-	n = int(r0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func Exit(code int) {
 	Syscall(SYS_EXIT_GROUP, uintptr(code), 0, 0)
 	return
@@ -1582,6 +1565,23 @@ func mmap2(addr uintptr, length uintptr, prot int, flags int, fd int, pageOffset
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
+	var _p0 unsafe.Pointer
+	if len(events) > 0 {
+		_p0 = unsafe.Pointer(&events[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	r0, _, e1 := Syscall6(SYS_EPOLL_WAIT, uintptr(epfd), uintptr(_p0), uintptr(len(events)), uintptr(msec), 0, 0)
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func getrlimit(resource int, rlim *rlimit32) (err error) {
 	_, _, e1 := RawSyscall(SYS_GETRLIMIT, uintptr(resource), uintptr(unsafe.Pointer(rlim)), 0)
 	if e1 != 0 {

unix/zsyscall_linux_amd64.go

@@ -370,23 +370,6 @@ func EpollCtl(epfd int, op int, fd int, event *EpollEvent) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
-	var _p0 unsafe.Pointer
-	if len(events) > 0 {
-		_p0 = unsafe.Pointer(&events[0])
-	} else {
-		_p0 = unsafe.Pointer(&_zero)
-	}
-	r0, _, e1 := Syscall6(SYS_EPOLL_WAIT, uintptr(epfd), uintptr(_p0), uintptr(len(events)), uintptr(msec), 0, 0)
-	n = int(r0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func Exit(code int) {
 	Syscall(SYS_EXIT_GROUP, uintptr(code), 0, 0)
 	return
@@ -1226,6 +1209,23 @@ func Dup2(oldfd int, newfd int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
+	var _p0 unsafe.Pointer
+	if len(events) > 0 {
+		_p0 = unsafe.Pointer(&events[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	r0, _, e1 := Syscall6(SYS_EPOLL_WAIT, uintptr(epfd), uintptr(_p0), uintptr(len(events)), uintptr(msec), 0, 0)
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Fadvise(fd int, offset int64, length int64, advice int) (err error) {
 	_, _, e1 := Syscall6(SYS_FADVISE64, uintptr(fd), uintptr(offset), uintptr(length), uintptr(advice), 0, 0)
 	if e1 != 0 {

unix/zsyscall_linux_arm.go

@@ -370,23 +370,6 @@ func EpollCtl(epfd int, op int, fd int, event *EpollEvent) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
-	var _p0 unsafe.Pointer
-	if len(events) > 0 {
-		_p0 = unsafe.Pointer(&events[0])
-	} else {
-		_p0 = unsafe.Pointer(&_zero)
-	}
-	r0, _, e1 := Syscall6(SYS_EPOLL_WAIT, uintptr(epfd), uintptr(_p0), uintptr(len(events)), uintptr(msec), 0, 0)
-	n = int(r0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func Exit(code int) {
 	Syscall(SYS_EXIT_GROUP, uintptr(code), 0, 0)
 	return
@@ -1649,6 +1632,23 @@ func Gettimeofday(tv *Timeval) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
+	var _p0 unsafe.Pointer
+	if len(events) > 0 {
+		_p0 = unsafe.Pointer(&events[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	r0, _, e1 := Syscall6(SYS_EPOLL_WAIT, uintptr(epfd), uintptr(_p0), uintptr(len(events)), uintptr(msec), 0, 0)
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Pread(fd int, p []byte, offset int64) (n int, err error) {
 	var _p0 unsafe.Pointer
 	if len(p) > 0 {

unix/zsyscall_linux_arm64.go

@@ -370,23 +370,6 @@ func EpollCtl(epfd int, op int, fd int, event *EpollEvent) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
-	var _p0 unsafe.Pointer
-	if len(events) > 0 {
-		_p0 = unsafe.Pointer(&events[0])
-	} else {
-		_p0 = unsafe.Pointer(&_zero)
-	}
-	r0, _, e1 := Syscall6(SYS_EPOLL_WAIT, uintptr(epfd), uintptr(_p0), uintptr(len(events)), uintptr(msec), 0, 0)
-	n = int(r0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func Exit(code int) {
 	Syscall(SYS_EXIT_GROUP, uintptr(code), 0, 0)
 	return
@@ -1216,6 +1199,23 @@ func Munlockall() (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
+	var _p0 unsafe.Pointer
+	if len(events) > 0 {
+		_p0 = unsafe.Pointer(&events[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	r0, _, e1 := Syscall6(SYS_EPOLL_PWAIT, uintptr(epfd), uintptr(_p0), uintptr(len(events)), uintptr(msec), 0, 0)
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Fchown(fd int, uid int, gid int) (err error) {
 	_, _, e1 := Syscall(SYS_FCHOWN, uintptr(fd), uintptr(uid), uintptr(gid))
 	if e1 != 0 {

unix/zsyscall_linux_mips64.go

@@ -370,23 +370,6 @@ func EpollCtl(epfd int, op int, fd int, event *EpollEvent) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
-	var _p0 unsafe.Pointer
-	if len(events) > 0 {
-		_p0 = unsafe.Pointer(&events[0])
-	} else {
-		_p0 = unsafe.Pointer(&_zero)
-	}
-	r0, _, e1 := Syscall6(SYS_EPOLL_WAIT, uintptr(epfd), uintptr(_p0), uintptr(len(events)), uintptr(msec), 0, 0)
-	n = int(r0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func Exit(code int) {
 	Syscall(SYS_EXIT_GROUP, uintptr(code), 0, 0)
 	return
@@ -1216,6 +1199,23 @@ func Munlockall() (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
+	var _p0 unsafe.Pointer
+	if len(events) > 0 {
+		_p0 = unsafe.Pointer(&events[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	r0, _, e1 := Syscall6(SYS_EPOLL_WAIT, uintptr(epfd), uintptr(_p0), uintptr(len(events)), uintptr(msec), 0, 0)
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Fchown(fd int, uid int, gid int) (err error) {
 	_, _, e1 := Syscall(SYS_FCHOWN, uintptr(fd), uintptr(uid), uintptr(gid))
 	if e1 != 0 {

unix/zsyscall_linux_mips64le.go

@@ -370,23 +370,6 @@ func EpollCtl(epfd int, op int, fd int, event *EpollEvent) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
-	var _p0 unsafe.Pointer
-	if len(events) > 0 {
-		_p0 = unsafe.Pointer(&events[0])
-	} else {
-		_p0 = unsafe.Pointer(&_zero)
-	}
-	r0, _, e1 := Syscall6(SYS_EPOLL_WAIT, uintptr(epfd), uintptr(_p0), uintptr(len(events)), uintptr(msec), 0, 0)
-	n = int(r0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func Exit(code int) {
 	Syscall(SYS_EXIT_GROUP, uintptr(code), 0, 0)
 	return
@@ -1216,6 +1199,23 @@ func Munlockall() (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
+	var _p0 unsafe.Pointer
+	if len(events) > 0 {
+		_p0 = unsafe.Pointer(&events[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	r0, _, e1 := Syscall6(SYS_EPOLL_WAIT, uintptr(epfd), uintptr(_p0), uintptr(len(events)), uintptr(msec), 0, 0)
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Fchown(fd int, uid int, gid int) (err error) {
 	_, _, e1 := Syscall(SYS_FCHOWN, uintptr(fd), uintptr(uid), uintptr(gid))
 	if e1 != 0 {

unix/zsyscall_linux_ppc64.go

@@ -370,23 +370,6 @@ func EpollCtl(epfd int, op int, fd int, event *EpollEvent) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
-	var _p0 unsafe.Pointer
-	if len(events) > 0 {
-		_p0 = unsafe.Pointer(&events[0])
-	} else {
-		_p0 = unsafe.Pointer(&_zero)
-	}
-	r0, _, e1 := Syscall6(SYS_EPOLL_WAIT, uintptr(epfd), uintptr(_p0), uintptr(len(events)), uintptr(msec), 0, 0)
-	n = int(r0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func Exit(code int) {
 	Syscall(SYS_EXIT_GROUP, uintptr(code), 0, 0)
 	return
@@ -1216,6 +1199,23 @@ func Munlockall() (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
+	var _p0 unsafe.Pointer
+	if len(events) > 0 {
+		_p0 = unsafe.Pointer(&events[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	r0, _, e1 := Syscall6(SYS_EPOLL_WAIT, uintptr(epfd), uintptr(_p0), uintptr(len(events)), uintptr(msec), 0, 0)
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Dup2(oldfd int, newfd int) (err error) {
 	_, _, e1 := Syscall(SYS_DUP2, uintptr(oldfd), uintptr(newfd), 0)
 	if e1 != 0 {

unix/zsyscall_linux_ppc64le.go

@@ -370,23 +370,6 @@ func EpollCtl(epfd int, op int, fd int, event *EpollEvent) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
-	var _p0 unsafe.Pointer
-	if len(events) > 0 {
-		_p0 = unsafe.Pointer(&events[0])
-	} else {
-		_p0 = unsafe.Pointer(&_zero)
-	}
-	r0, _, e1 := Syscall6(SYS_EPOLL_WAIT, uintptr(epfd), uintptr(_p0), uintptr(len(events)), uintptr(msec), 0, 0)
-	n = int(r0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func Exit(code int) {
 	Syscall(SYS_EXIT_GROUP, uintptr(code), 0, 0)
 	return
@@ -1216,6 +1199,23 @@ func Munlockall() (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
+	var _p0 unsafe.Pointer
+	if len(events) > 0 {
+		_p0 = unsafe.Pointer(&events[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	r0, _, e1 := Syscall6(SYS_EPOLL_WAIT, uintptr(epfd), uintptr(_p0), uintptr(len(events)), uintptr(msec), 0, 0)
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Dup2(oldfd int, newfd int) (err error) {
 	_, _, e1 := Syscall(SYS_DUP2, uintptr(oldfd), uintptr(newfd), 0)
 	if e1 != 0 {

unix/ztypes_linux_arm64.go

@@ -580,6 +580,7 @@ type Ustat_t struct {
 
 type EpollEvent struct {
 	Events uint32
+	PadFd  int32
 	Fd     int32
 	Pad    int32
 }