unix: add Fstatat on Linux for all GOOSes

Looks like it's enough to just add wrappers pointing to the
corresponding SYS_FSTATAT{,64} or SYS_NEWFSTATAT syscall. Add a test to
verify that assumption which checks that the returned stat data matches
what is returned by Stat/Lstat.

Also add the AT_NO_AUTOMOUNT constant which may be used for the flags
parmeter.

Fixes golang/go#14216

Change-Id: I73f27b483bd97d2dcf09d4b95a7957e75d194395
Reviewed-on: https://go-review.googlesource.com/79795
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

unix/linux/types.go

@@ -512,6 +512,7 @@ type EpollEvent C.struct_my_epoll_event
 
 const (
 	AT_FDCWD            = C.AT_FDCWD
+	AT_NO_AUTOMOUNT     = C.AT_NO_AUTOMOUNT
 	AT_REMOVEDIR        = C.AT_REMOVEDIR
 	AT_SYMLINK_FOLLOW   = C.AT_SYMLINK_FOLLOW
 	AT_SYMLINK_NOFOLLOW = C.AT_SYMLINK_NOFOLLOW

unix/syscall_linux.go

@@ -1410,7 +1410,6 @@ func Vmsplice(fd int, iovs []Iovec, flags int) (int, error) {
 // Msgget
 // Msgrcv
 // Msgsnd
-// Newfstatat
 // Nfsservctl
 // Personality
 // Pselect6

unix/syscall_linux_386.go

@@ -54,6 +54,7 @@ func Pipe2(p []int, flags int) (err error) {
 //sys	Fadvise(fd int, offset int64, length int64, advice int) (err error) = SYS_FADVISE64_64
 //sys	Fchown(fd int, uid int, gid int) (err error) = SYS_FCHOWN32
 //sys	Fstat(fd int, stat *Stat_t) (err error) = SYS_FSTAT64
+//sys	Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) = SYS_FSTATAT64
 //sys	Ftruncate(fd int, length int64) (err error) = SYS_FTRUNCATE64
 //sysnb	Getegid() (egid int) = SYS_GETEGID32
 //sysnb	Geteuid() (euid int) = SYS_GETEUID32

unix/syscall_linux_amd64.go

@@ -11,6 +11,7 @@ package unix
 //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)
+//sys	Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) = SYS_NEWFSTATAT
 //sys	Fstatfs(fd int, buf *Statfs_t) (err error)
 //sys	Ftruncate(fd int, length int64) (err error)
 //sysnb	Getegid() (egid int)

unix/syscall_linux_arm.go

@@ -77,6 +77,7 @@ func Seek(fd int, offset int64, whence int) (newoffset int64, err error) {
 //sys	Dup2(oldfd int, newfd int) (err error)
 //sys	Fchown(fd int, uid int, gid int) (err error) = SYS_FCHOWN32
 //sys	Fstat(fd int, stat *Stat_t) (err error) = SYS_FSTAT64
+//sys	Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) = SYS_FSTATAT64
 //sysnb	Getegid() (egid int) = SYS_GETEGID32
 //sysnb	Geteuid() (euid int) = SYS_GETEUID32
 //sysnb	Getgid() (gid int) = SYS_GETGID32

unix/syscall_linux_mips64x.go

@@ -10,6 +10,7 @@ package unix
 //sys	Dup2(oldfd int, newfd int) (err error)
 //sys	EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
 //sys	Fchown(fd int, uid int, gid int) (err error)
+//sys	Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) = SYS_NEWFSTATAT
 //sys	Fstatfs(fd int, buf *Statfs_t) (err error)
 //sys	Ftruncate(fd int, length int64) (err error)
 //sysnb	Getegid() (egid int)

unix/syscall_linux_mipsx.go

@@ -65,6 +65,7 @@ func Syscall9(trap, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr,
 
 //sys	Lstat(path string, stat *Stat_t) (err error) = SYS_LSTAT64
 //sys	Fstat(fd int, stat *Stat_t) (err error) = SYS_FSTAT64
+//sys	Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) = SYS_FSTATAT64
 //sys	Stat(path string, stat *Stat_t) (err error) = SYS_STAT64
 
 //sys	Utime(path string, buf *Utimbuf) (err error)

unix/syscall_linux_ppc64x.go

@@ -11,6 +11,7 @@ package unix
 //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)
+//sys	Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) = SYS_NEWFSTATAT
 //sys	Fstatfs(fd int, buf *Statfs_t) (err error)
 //sys	Ftruncate(fd int, length int64) (err error)
 //sysnb	Getegid() (egid int)

unix/syscall_linux_s390x.go

@@ -15,6 +15,7 @@ import (
 //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)
+//sys	Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) = SYS_NEWFSTATAT
 //sys	Fstatfs(fd int, buf *Statfs_t) (err error)
 //sys	Ftruncate(fd int, length int64) (err error)
 //sysnb	Getegid() (egid int)

unix/syscall_linux_sparc64.go

@@ -10,6 +10,7 @@ package unix
 //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)
+//sys	Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) = SYS_FSTATAT64
 //sys	Fstatfs(fd int, buf *Statfs_t) (err error)
 //sys	Ftruncate(fd int, length int64) (err error)
 //sysnb	Getegid() (egid int)

unix/syscall_linux_test.go

@@ -195,6 +195,44 @@ func TestUname(t *testing.T) {
 	t.Logf("OS: %s/%s %s", string(utsname.Sysname[:]), string(utsname.Machine[:]), string(utsname.Release[:]))
 }
 
+func TestFstatat(t *testing.T) {
+	defer chtmpdir(t)()
+
+	touch(t, "file1")
+
+	var st1 unix.Stat_t
+	err := unix.Stat("file1", &st1)
+	if err != nil {
+		t.Fatalf("Stat: %v", err)
+	}
+
+	var st2 unix.Stat_t
+	err = unix.Fstatat(unix.AT_FDCWD, "file1", &st2, 0)
+	if err != nil {
+		t.Fatalf("Fstatat: %v", err)
+	}
+
+	if st1 != st2 {
+		t.Errorf("Fstatat: returned stat does not match Stat")
+	}
+
+	os.Symlink("file1", "symlink1")
+
+	err = unix.Lstat("symlink1", &st1)
+	if err != nil {
+		t.Fatalf("Lstat: %v", err)
+	}
+
+	err = unix.Fstatat(unix.AT_FDCWD, "symlink1", &st2, unix.AT_SYMLINK_NOFOLLOW)
+	if err != nil {
+		t.Fatalf("Fstatat: %v", err)
+	}
+
+	if st1 != st2 {
+		t.Errorf("Fstatat: returned stat does not match Lstat")
+	}
+}
+
 // utilities taken from os/os_test.go
 
 func touch(t *testing.T, name string) {

unix/zsyscall_linux_386.go

@@ -1569,6 +1569,21 @@ func Fstat(fd int, stat *Stat_t) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	_, _, e1 := Syscall6(SYS_FSTATAT64, uintptr(dirfd), uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), uintptr(flags), 0, 0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Ftruncate(fd int, length int64) (err error) {
 	_, _, e1 := Syscall(SYS_FTRUNCATE64, uintptr(fd), uintptr(length), uintptr(length>>32))
 	if e1 != 0 {

unix/zsyscall_linux_amd64.go

@@ -1566,6 +1566,21 @@ func Fstat(fd int, stat *Stat_t) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	_, _, e1 := Syscall6(SYS_NEWFSTATAT, uintptr(dirfd), uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), uintptr(flags), 0, 0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Fstatfs(fd int, buf *Statfs_t) (err error) {
 	_, _, e1 := Syscall(SYS_FSTATFS, uintptr(fd), uintptr(unsafe.Pointer(buf)), 0)
 	if e1 != 0 {

unix/zsyscall_linux_arm.go

@@ -1728,6 +1728,21 @@ func Fstat(fd int, stat *Stat_t) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	_, _, e1 := Syscall6(SYS_FSTATAT64, uintptr(dirfd), uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), uintptr(flags), 0, 0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Getegid() (egid int) {
 	r0, _, _ := RawSyscall(SYS_GETEGID32, 0, 0, 0)
 	egid = int(r0)

unix/zsyscall_linux_mips.go

@@ -2014,6 +2014,21 @@ func Fstat(fd int, stat *Stat_t) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	_, _, e1 := Syscall6(SYS_FSTATAT64, uintptr(dirfd), uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), uintptr(flags), 0, 0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Stat(path string, stat *Stat_t) (err error) {
 	var _p0 *byte
 	_p0, err = BytePtrFromString(path)

unix/zsyscall_linux_mips64.go

@@ -1546,6 +1546,21 @@ func Fchown(fd int, uid int, gid int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	_, _, e1 := Syscall6(SYS_NEWFSTATAT, uintptr(dirfd), uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), uintptr(flags), 0, 0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Fstatfs(fd int, buf *Statfs_t) (err error) {
 	_, _, e1 := Syscall(SYS_FSTATFS, uintptr(fd), uintptr(unsafe.Pointer(buf)), 0)
 	if e1 != 0 {

unix/zsyscall_linux_mips64le.go

@@ -1546,6 +1546,21 @@ func Fchown(fd int, uid int, gid int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	_, _, e1 := Syscall6(SYS_NEWFSTATAT, uintptr(dirfd), uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), uintptr(flags), 0, 0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Fstatfs(fd int, buf *Statfs_t) (err error) {
 	_, _, e1 := Syscall(SYS_FSTATFS, uintptr(fd), uintptr(unsafe.Pointer(buf)), 0)
 	if e1 != 0 {

unix/zsyscall_linux_mipsle.go

@@ -2014,6 +2014,21 @@ func Fstat(fd int, stat *Stat_t) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	_, _, e1 := Syscall6(SYS_FSTATAT64, uintptr(dirfd), uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), uintptr(flags), 0, 0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Stat(path string, stat *Stat_t) (err error) {
 	var _p0 *byte
 	_p0, err = BytePtrFromString(path)

unix/zsyscall_linux_ppc64.go

@@ -1556,6 +1556,21 @@ func Fstat(fd int, stat *Stat_t) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	_, _, e1 := Syscall6(SYS_NEWFSTATAT, uintptr(dirfd), uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), uintptr(flags), 0, 0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Fstatfs(fd int, buf *Statfs_t) (err error) {
 	_, _, e1 := Syscall(SYS_FSTATFS, uintptr(fd), uintptr(unsafe.Pointer(buf)), 0)
 	if e1 != 0 {

unix/zsyscall_linux_ppc64le.go

@@ -1556,6 +1556,21 @@ func Fstat(fd int, stat *Stat_t) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	_, _, e1 := Syscall6(SYS_NEWFSTATAT, uintptr(dirfd), uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), uintptr(flags), 0, 0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Fstatfs(fd int, buf *Statfs_t) (err error) {
 	_, _, e1 := Syscall(SYS_FSTATFS, uintptr(fd), uintptr(unsafe.Pointer(buf)), 0)
 	if e1 != 0 {

unix/zsyscall_linux_s390x.go

@@ -1566,6 +1566,21 @@ func Fstat(fd int, stat *Stat_t) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	_, _, e1 := Syscall6(SYS_NEWFSTATAT, uintptr(dirfd), uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), uintptr(flags), 0, 0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Fstatfs(fd int, buf *Statfs_t) (err error) {
 	_, _, e1 := Syscall(SYS_FSTATFS, uintptr(fd), uintptr(unsafe.Pointer(buf)), 0)
 	if e1 != 0 {

unix/ztypes_linux_386.go

@@ -644,6 +644,7 @@ type EpollEvent struct {
 
 const (
 	AT_FDCWD            = -0x64
+	AT_NO_AUTOMOUNT     = 0x800
 	AT_REMOVEDIR        = 0x200
 	AT_SYMLINK_FOLLOW   = 0x400
 	AT_SYMLINK_NOFOLLOW = 0x100

unix/ztypes_linux_amd64.go

@@ -662,6 +662,7 @@ type EpollEvent struct {
 
 const (
 	AT_FDCWD            = -0x64
+	AT_NO_AUTOMOUNT     = 0x800
 	AT_REMOVEDIR        = 0x200
 	AT_SYMLINK_FOLLOW   = 0x400
 	AT_SYMLINK_NOFOLLOW = 0x100

unix/ztypes_linux_arm.go

@@ -633,6 +633,7 @@ type EpollEvent struct {
 
 const (
 	AT_FDCWD            = -0x64
+	AT_NO_AUTOMOUNT     = 0x800
 	AT_REMOVEDIR        = 0x200
 	AT_SYMLINK_FOLLOW   = 0x400
 	AT_SYMLINK_NOFOLLOW = 0x100

unix/ztypes_linux_arm64.go

@@ -641,6 +641,7 @@ type EpollEvent struct {
 
 const (
 	AT_FDCWD            = -0x64
+	AT_NO_AUTOMOUNT     = 0x800
 	AT_REMOVEDIR        = 0x200
 	AT_SYMLINK_FOLLOW   = 0x400
 	AT_SYMLINK_NOFOLLOW = 0x100

unix/ztypes_linux_mips.go

@@ -638,6 +638,7 @@ type EpollEvent struct {
 
 const (
 	AT_FDCWD            = -0x64
+	AT_NO_AUTOMOUNT     = 0x800
 	AT_REMOVEDIR        = 0x200
 	AT_SYMLINK_FOLLOW   = 0x400
 	AT_SYMLINK_NOFOLLOW = 0x100

unix/ztypes_linux_mips64.go

@@ -643,6 +643,7 @@ type EpollEvent struct {
 
 const (
 	AT_FDCWD            = -0x64
+	AT_NO_AUTOMOUNT     = 0x800
 	AT_REMOVEDIR        = 0x200
 	AT_SYMLINK_FOLLOW   = 0x400
 	AT_SYMLINK_NOFOLLOW = 0x100

unix/ztypes_linux_mips64le.go

@@ -643,6 +643,7 @@ type EpollEvent struct {
 
 const (
 	AT_FDCWD            = -0x64
+	AT_NO_AUTOMOUNT     = 0x800
 	AT_REMOVEDIR        = 0x200
 	AT_SYMLINK_FOLLOW   = 0x400
 	AT_SYMLINK_NOFOLLOW = 0x100

unix/ztypes_linux_mipsle.go

@@ -638,6 +638,7 @@ type EpollEvent struct {
 
 const (
 	AT_FDCWD            = -0x64
+	AT_NO_AUTOMOUNT     = 0x800
 	AT_REMOVEDIR        = 0x200
 	AT_SYMLINK_FOLLOW   = 0x400
 	AT_SYMLINK_NOFOLLOW = 0x100

unix/ztypes_linux_ppc64.go

@@ -651,6 +651,7 @@ type EpollEvent struct {
 
 const (
 	AT_FDCWD            = -0x64
+	AT_NO_AUTOMOUNT     = 0x800
 	AT_REMOVEDIR        = 0x200
 	AT_SYMLINK_FOLLOW   = 0x400
 	AT_SYMLINK_NOFOLLOW = 0x100

unix/ztypes_linux_ppc64le.go

@@ -651,6 +651,7 @@ type EpollEvent struct {
 
 const (
 	AT_FDCWD            = -0x64
+	AT_NO_AUTOMOUNT     = 0x800
 	AT_REMOVEDIR        = 0x200
 	AT_SYMLINK_FOLLOW   = 0x400
 	AT_SYMLINK_NOFOLLOW = 0x100

unix/ztypes_linux_s390x.go

@@ -668,6 +668,7 @@ type EpollEvent struct {
 
 const (
 	AT_FDCWD            = -0x64
+	AT_NO_AUTOMOUNT     = 0x800
 	AT_REMOVEDIR        = 0x200
 	AT_SYMLINK_FOLLOW   = 0x400
 	AT_SYMLINK_NOFOLLOW = 0x100