unix: use Renameat2 to implement Renameat on linux/riscv64

On linux/riscv64, the renameat syscall no longer exists and has been
superseded by renameat2. Use Renameat2 to implement Renameat on
linux/riscv64.

Based on a patch by Ryan O'Leary.

Updates golang/go#27532

Change-Id: I7c60c7f824750408265f67397b8ac1fa7226f425
Reviewed-on: https://go-review.googlesource.com/c/157899
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

unix/syscall_linux.go

@@ -1442,7 +1442,6 @@ func Getpgrp() (pid int) {
 //sys	Pselect(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timespec, sigmask *Sigset_t) (n int, err error) = SYS_PSELECT6
 //sys	read(fd int, p []byte) (n int, err error)
 //sys	Removexattr(path string, attr string) (err error)
-//sys	Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error)
 //sys	Renameat2(olddirfd int, oldpath string, newdirfd int, newpath string, flags uint) (err error)
 //sys	RequestKey(keyType string, description string, callback string, destRingid int) (id int, err error)
 //sys	Setdomainname(p []byte) (err error)

unix/syscall_linux_386.go

@@ -68,6 +68,7 @@ func Pipe2(p []int, flags int) (err error) {
 //sys	Lstat(path string, stat *Stat_t) (err error) = SYS_LSTAT64
 //sys	Pread(fd int, p []byte, offset int64) (n int, err error) = SYS_PREAD64
 //sys	Pwrite(fd int, p []byte, offset int64) (n int, err error) = SYS_PWRITE64
+//sys	Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error)
 //sys	sendfile(outfd int, infd int, offset *int64, count int) (written int, err error) = SYS_SENDFILE64
 //sys	Setfsgid(gid int) (err error) = SYS_SETFSGID32
 //sys	Setfsuid(uid int) (err error) = SYS_SETFSUID32

unix/syscall_linux_amd64.go

@@ -43,6 +43,7 @@ func Lstat(path string, stat *Stat_t) (err error) {
 //sys	Pause() (err error)
 //sys	Pread(fd int, p []byte, offset int64) (n int, err error) = SYS_PREAD64
 //sys	Pwrite(fd int, p []byte, offset int64) (n int, err error) = SYS_PWRITE64
+//sys	Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error)
 //sys	Seek(fd int, offset int64, whence int) (off int64, err error) = SYS_LSEEK
 
 func Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error) {

unix/syscall_linux_arm.go

@@ -89,6 +89,7 @@ func Seek(fd int, offset int64, whence int) (newoffset int64, err error) {
 //sys	Listen(s int, n int) (err error)
 //sys	Lstat(path string, stat *Stat_t) (err error) = SYS_LSTAT64
 //sys	Pause() (err error)
+//sys	Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error)
 //sys	sendfile(outfd int, infd int, offset *int64, count int) (written int, err error) = SYS_SENDFILE64
 //sys	Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error) = SYS__NEWSELECT
 //sys	Setfsgid(gid int) (err error) = SYS_SETFSGID32

unix/syscall_linux_arm64.go

@@ -30,6 +30,7 @@ func EpollCreate(size int) (fd int, err error) {
 //sys	Listen(s int, n int) (err error)
 //sys	Pread(fd int, p []byte, offset int64) (n int, err error) = SYS_PREAD64
 //sys	Pwrite(fd int, p []byte, offset int64) (n int, err error) = SYS_PWRITE64
+//sys	Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error)
 //sys	Seek(fd int, offset int64, whence int) (off int64, err error) = SYS_LSEEK
 
 func Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error) {

unix/syscall_linux_mips64x.go

@@ -24,6 +24,7 @@ package unix
 //sys	Pause() (err error)
 //sys	Pread(fd int, p []byte, offset int64) (n int, err error) = SYS_PREAD64
 //sys	Pwrite(fd int, p []byte, offset int64) (n int, err error) = SYS_PWRITE64
+//sys	Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error)
 //sys	Seek(fd int, offset int64, whence int) (off int64, err error) = SYS_LSEEK
 
 func Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error) {

unix/syscall_linux_mipsx.go

@@ -28,6 +28,7 @@ func Syscall9(trap, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr,
 //sys	Listen(s int, n int) (err error)
 //sys	Pread(fd int, p []byte, offset int64) (n int, err error) = SYS_PREAD64
 //sys	Pwrite(fd int, p []byte, offset int64) (n int, err error) = SYS_PWRITE64
+//sys	Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error)
 //sys	Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error) = SYS__NEWSELECT
 //sys	sendfile(outfd int, infd int, offset *int64, count int) (written int, err error) = SYS_SENDFILE64
 //sys	Setfsgid(gid int) (err error)

unix/syscall_linux_ppc64x.go

@@ -30,6 +30,7 @@ package unix
 //sys	Pause() (err error)
 //sys	Pread(fd int, p []byte, offset int64) (n int, err error) = SYS_PREAD64
 //sys	Pwrite(fd int, p []byte, offset int64) (n int, err error) = SYS_PWRITE64
+//sys	Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error)
 //sys	Seek(fd int, offset int64, whence int) (off int64, err error) = SYS_LSEEK
 //sys	Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error) = SYS__NEWSELECT
 //sys	sendfile(outfd int, infd int, offset *int64, count int) (written int, err error)

unix/syscall_linux_riscv64.go

@@ -207,3 +207,7 @@ func Poll(fds []PollFd, timeout int) (n int, err error) {
 	}
 	return ppoll(&fds[0], len(fds), ts, nil)
 }
+
+func Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error) {
+	return Renameat2(olddirfd, oldpath, newdirfd, newpath, 0)
+}

unix/syscall_linux_s390x.go

@@ -30,6 +30,7 @@ import (
 //sys	Pause() (err error)
 //sys	Pread(fd int, p []byte, offset int64) (n int, err error) = SYS_PREAD64
 //sys	Pwrite(fd int, p []byte, offset int64) (n int, err error) = SYS_PWRITE64
+//sys	Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error)
 //sys	Seek(fd int, offset int64, whence int) (off int64, err error) = SYS_LSEEK
 //sys	Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error)
 //sys	sendfile(outfd int, infd int, offset *int64, count int) (written int, err error)

unix/syscall_linux_sparc64.go

@@ -26,6 +26,7 @@ package unix
 //sys	Pause() (err error)
 //sys	Pread(fd int, p []byte, offset int64) (n int, err error) = SYS_PREAD64
 //sys	Pwrite(fd int, p []byte, offset int64) (n int, err error) = SYS_PWRITE64
+//sys	Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error)
 //sys	Seek(fd int, offset int64, whence int) (off int64, err error) = SYS_LSEEK
 //sys	Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error)
 //sys	sendfile(outfd int, infd int, offset *int64, count int) (written int, err error)