syscall: add support for s390x

On s390x char is unsigned. We cannot force it to be signed using
-fsigned-char (see arm64) because the s390x gccgo API is already
public and we need to stick as closely as possible to it to avoid
breaking existing projects. In order to match the gccgo API we
also force the RawSockaddr.Data and RawSockaddrUnix.Path fields
to be signed.

This CL adds a post-processing pass (mkpost.go) to mkall.sh in
order to export the types of fields in PtraceRegs on s390x
without affecting the API on other platforms. The types of these
fields match their counterparts in gccgo. mkpost.go also cleans
up the Pad_cgo* fields and X_* fields (these fields are not
exported by gccgo currently). It could be extended to add build
tags on platforms that need them.

Change-Id: I66bdf5b86ec98af70baf666989027bb354df9e3e
Reviewed-on: https://go-review.googlesource.com/20961Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/syscall/mkall.sh

@@ -207,6 +207,13 @@ linux_ppc64le)
 	mksysnum="./mksysnum_linux.pl $unistd_h"
 	mktypes="GOARCH=$GOARCH go tool cgo -godefs"
 	;;
+linux_s390x)
+	GOOSARCH_in=syscall_linux_s390x.go
+	unistd_h=/usr/include/asm/unistd.h
+	mkerrors="$mkerrors -m64"
+	mksysnum="./mksysnum_linux.pl $unistd_h"
+	mktypes="GOARCH=$GOARCH go tool cgo -godefs"
+	;;
 nacl_386)
 	mkerrors=""
 	mksyscall="./mksyscall.pl -l32 -nacl"
@@ -288,5 +295,5 @@ esac
 	if [ -n "$mksyscall" ]; then echo "$mksyscall $syscall_goos $GOOSARCH_in |gofmt >zsyscall_$GOOSARCH.go"; fi
 	if [ -n "$mksysctl" ]; then echo "$mksysctl |gofmt >$zsysctl"; fi
 	if [ -n "$mksysnum" ]; then echo "$mksysnum |gofmt >zsysnum_$GOOSARCH.go"; fi
-	if [ -n "$mktypes" ]; then echo "$mktypes types_$GOOS.go |gofmt >ztypes_$GOOSARCH.go"; fi
+	if [ -n "$mktypes" ]; then echo "$mktypes types_$GOOS.go |go run mkpost.go >ztypes_$GOOSARCH.go"; fi
 ) | $run

src/syscall/mkpost.go

+// Copyright 2016 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.
+
+// +build ignore
+
+// mkpost processes the output of cgo -godefs to
+// modify the generated types. It is used to clean up
+// the syscall API in an architecture specific manner.
+//
+// mkpost is run after cgo -godefs by mkall.sh.
+package main
+
+import (
+	"fmt"
+	"go/format"
+	"io/ioutil"
+	"log"
+	"os"
+	"regexp"
+)
+
+func main() {
+	b, err := ioutil.ReadAll(os.Stdin)
+	if err != nil {
+		log.Fatal(err)
+	}
+	s := string(b)
+
+	goarch := os.Getenv("GOARCH")
+	goos := os.Getenv("GOOS")
+	if goarch == "s390x" && goos == "linux" {
+		// Export the types of PtraceRegs fields.
+		re := regexp.MustCompile("ptrace(Psw|Fpregs|Per)")
+		s = re.ReplaceAllString(s, "Ptrace$1")
+
+		// Replace padding fields inserted by cgo with blank identifiers.
+		re = regexp.MustCompile("Pad_cgo[A-Za-z0-9_]*")
+		s = re.ReplaceAllString(s, "_")
+
+		// Replace other unwanted fields with blank identifiers.
+		re = regexp.MustCompile("X_[A-Za-z0-9_]*")
+		s = re.ReplaceAllString(s, "_")
+
+		// Force the type of RawSockaddr.Data to [14]int8 to match
+		// the existing gccgo API.
+		re = regexp.MustCompile("(Data\\s+\\[14\\])uint8")
+		s = re.ReplaceAllString(s, "${1}int8")
+	}
+
+	// gofmt
+	b, err = format.Source([]byte(s))
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Append this command to the header to show where the new file
+	// came from.
+	re := regexp.MustCompile("(cgo -godefs [a-zA-Z0-9_]+\\.go.*)")
+	s = re.ReplaceAllString(string(b), "$1 | go run mkpost.go")
+
+	fmt.Print(s)
+}

src/syscall/syscall_linux_s390x.go

+// Copyright 2016 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 syscall
+
+import "unsafe"
+
+const (
+	_SYS_dup      = SYS_DUP2
+	_SYS_getdents = SYS_GETDENTS64
+)
+
+//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	Fstatfs(fd int, buf *Statfs_t) (err error)
+//sys	Ftruncate(fd int, length int64) (err error)
+//sysnb	Getegid() (egid int)
+//sysnb	Geteuid() (euid int)
+//sysnb	Getgid() (gid int)
+//sysnb	Getrlimit(resource int, rlim *Rlimit) (err error) = SYS_GETRLIMIT
+//sysnb	Getuid() (uid int)
+//sysnb	InotifyInit() (fd int, err error)
+//sys	Lchown(path string, uid int, gid int) (err error)
+//sys	Lstat(path string, stat *Stat_t) (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	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)
+//sys	Setfsgid(gid int) (err error)
+//sys	Setfsuid(uid int) (err error)
+//sysnb	Setregid(rgid int, egid int) (err error)
+//sysnb	Setresgid(rgid int, egid int, sgid int) (err error)
+//sysnb	Setresuid(ruid int, euid int, suid int) (err error)
+//sysnb	Setrlimit(resource int, rlim *Rlimit) (err error)
+//sysnb	Setreuid(ruid int, euid int) (err error)
+//sys	Splice(rfd int, roff *int64, wfd int, woff *int64, len int, flags int) (n int64, err error)
+//sys	Stat(path string, stat *Stat_t) (err error)
+//sys	Statfs(path string, buf *Statfs_t) (err error)
+//sys	SyncFileRange(fd int, off int64, n int64, flags int) (err error) = SYS_SYNC_FILE_RANGE
+//sys	Truncate(path string, length int64) (err error)
+//sysnb	getgroups(n int, list *_Gid_t) (nn int, err error)
+//sysnb	setgroups(n int, list *_Gid_t) (err error)
+
+func Getpagesize() int { return 4096 }
+
+//sysnb	Gettimeofday(tv *Timeval) (err error)
+
+func Time(t *Time_t) (tt Time_t, err error) {
+	var tv Timeval
+	err = Gettimeofday(&tv)
+	if err != nil {
+		return 0, err
+	}
+	if t != nil {
+		*t = Time_t(tv.Sec)
+	}
+	return Time_t(tv.Sec), nil
+}
+
+func TimespecToNsec(ts Timespec) int64 { return int64(ts.Sec)*1e9 + int64(ts.Nsec) }
+
+func NsecToTimespec(nsec int64) (ts Timespec) {
+	ts.Sec = nsec / 1e9
+	ts.Nsec = nsec % 1e9
+	return
+}
+
+func TimevalToNsec(tv Timeval) int64 { return int64(tv.Sec)*1e9 + int64(tv.Usec)*1e3 }
+
+func NsecToTimeval(nsec int64) (tv Timeval) {
+	nsec += 999 // round up to microsecond
+	tv.Sec = nsec / 1e9
+	tv.Usec = nsec % 1e9 / 1e3
+	return
+}
+
+func Pipe(p []int) (err error) {
+	if len(p) != 2 {
+		return EINVAL
+	}
+	var pp [2]_C_int
+	err = pipe2(&pp, 0)
+	p[0] = int(pp[0])
+	p[1] = int(pp[1])
+	return
+}
+
+//sysnb pipe2(p *[2]_C_int, flags int) (err error)
+
+func Pipe2(p []int, flags int) (err error) {
+	if len(p) != 2 {
+		return EINVAL
+	}
+	var pp [2]_C_int
+	err = pipe2(&pp, flags)
+	p[0] = int(pp[0])
+	p[1] = int(pp[1])
+	return
+}
+
+// Linux on s390x uses the old mmap interface, which requires arguments to be passed in a struct.
+// mmap2 also requires arguments to be passed in a struct; it is currently not exposed in <asm/unistd.h>.
+func mmap(addr uintptr, length uintptr, prot int, flags int, fd int, offset int64) (xaddr uintptr, err error) {
+	mmap_args := [6]uintptr{addr, length, uintptr(prot), uintptr(flags), uintptr(fd), uintptr(offset)}
+	r0, _, e1 := Syscall(SYS_MMAP, uintptr(unsafe.Pointer(&mmap_args[0])), 0, 0)
+	use(unsafe.Pointer(&mmap_args[0]))
+	xaddr = uintptr(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// On s390x Linux, all the socket calls go through an extra indirection.
+// The arguments to the underlying system call are the number below
+// and a pointer to an array of uintptr.  We hide the pointer in the
+// socketcall assembly to avoid allocation on every system call.
+
+const (
+	// see linux/net.h
+	_SOCKET      = 1
+	_BIND        = 2
+	_CONNECT     = 3
+	_LISTEN      = 4
+	_ACCEPT      = 5
+	_GETSOCKNAME = 6
+	_GETPEERNAME = 7
+	_SOCKETPAIR  = 8
+	_SEND        = 9
+	_RECV        = 10
+	_SENDTO      = 11
+	_RECVFROM    = 12
+	_SHUTDOWN    = 13
+	_SETSOCKOPT  = 14
+	_GETSOCKOPT  = 15
+	_SENDMSG     = 16
+	_RECVMSG     = 17
+	_ACCEPT4     = 18
+	_RECVMMSG    = 19
+	_SENDMMSG    = 20
+)
+
+func socketcall(call int, a0, a1, a2, a3, a4, a5 uintptr) (n int, err Errno)
+func rawsocketcall(call int, a0, a1, a2, a3, a4, a5 uintptr) (n int, err Errno)
+
+func accept(s int, rsa *RawSockaddrAny, addrlen *_Socklen) (fd int, err error) {
+	fd, e := socketcall(_ACCEPT, uintptr(s), uintptr(unsafe.Pointer(rsa)), uintptr(unsafe.Pointer(addrlen)), 0, 0, 0)
+	if e != 0 {
+		err = e
+	}
+	return
+}
+
+func accept4(s int, rsa *RawSockaddrAny, addrlen *_Socklen, flags int) (fd int, err error) {
+	fd, e := socketcall(_ACCEPT4, uintptr(s), uintptr(unsafe.Pointer(rsa)), uintptr(unsafe.Pointer(addrlen)), uintptr(flags), 0, 0)
+	if e != 0 {
+		err = e
+	}
+	return
+}
+
+func getsockname(s int, rsa *RawSockaddrAny, addrlen *_Socklen) (err error) {
+	_, e := rawsocketcall(_GETSOCKNAME, uintptr(s), uintptr(unsafe.Pointer(rsa)), uintptr(unsafe.Pointer(addrlen)), 0, 0, 0)
+	if e != 0 {
+		err = e
+	}
+	return
+}
+
+func getpeername(s int, rsa *RawSockaddrAny, addrlen *_Socklen) (err error) {
+	_, e := rawsocketcall(_GETPEERNAME, uintptr(s), uintptr(unsafe.Pointer(rsa)), uintptr(unsafe.Pointer(addrlen)), 0, 0, 0)
+	if e != 0 {
+		err = e
+	}
+	return
+}
+
+func socketpair(domain int, typ int, flags int, fd *[2]int32) (err error) {
+	_, e := rawsocketcall(_SOCKETPAIR, uintptr(domain), uintptr(typ), uintptr(flags), uintptr(unsafe.Pointer(fd)), 0, 0)
+	if e != 0 {
+		err = e
+	}
+	return
+}
+
+func bind(s int, addr unsafe.Pointer, addrlen _Socklen) (err error) {
+	_, e := socketcall(_BIND, uintptr(s), uintptr(addr), uintptr(addrlen), 0, 0, 0)
+	if e != 0 {
+		err = e
+	}
+	return
+}
+
+func connect(s int, addr unsafe.Pointer, addrlen _Socklen) (err error) {
+	_, e := socketcall(_CONNECT, uintptr(s), uintptr(addr), uintptr(addrlen), 0, 0, 0)
+	if e != 0 {
+		err = e
+	}
+	return
+}
+
+func socket(domain int, typ int, proto int) (fd int, err error) {
+	fd, e := rawsocketcall(_SOCKET, uintptr(domain), uintptr(typ), uintptr(proto), 0, 0, 0)
+	if e != 0 {
+		err = e
+	}
+	return
+}
+
+func getsockopt(s int, level int, name int, val unsafe.Pointer, vallen *_Socklen) (err error) {
+	_, e := socketcall(_GETSOCKOPT, uintptr(s), uintptr(level), uintptr(name), uintptr(val), uintptr(unsafe.Pointer(vallen)), 0)
+	if e != 0 {
+		err = e
+	}
+	return
+}
+
+func setsockopt(s int, level int, name int, val unsafe.Pointer, vallen uintptr) (err error) {
+	_, e := socketcall(_SETSOCKOPT, uintptr(s), uintptr(level), uintptr(name), uintptr(val), vallen, 0)
+	if e != 0 {
+		err = e
+	}
+	return
+}
+
+func recvfrom(s int, p []byte, flags int, from *RawSockaddrAny, fromlen *_Socklen) (n int, err error) {
+	var base uintptr
+	if len(p) > 0 {
+		base = uintptr(unsafe.Pointer(&p[0]))
+	}
+	n, e := socketcall(_RECVFROM, uintptr(s), base, uintptr(len(p)), uintptr(flags), uintptr(unsafe.Pointer(from)), uintptr(unsafe.Pointer(fromlen)))
+	if e != 0 {
+		err = e
+	}
+	return
+}
+
+func sendto(s int, p []byte, flags int, to unsafe.Pointer, addrlen _Socklen) (err error) {
+	var base uintptr
+	if len(p) > 0 {
+		base = uintptr(unsafe.Pointer(&p[0]))
+	}
+	_, e := socketcall(_SENDTO, uintptr(s), base, uintptr(len(p)), uintptr(flags), uintptr(to), uintptr(addrlen))
+	if e != 0 {
+		err = e
+	}
+	return
+}
+
+func recvmsg(s int, msg *Msghdr, flags int) (n int, err error) {
+	n, e := socketcall(_RECVMSG, uintptr(s), uintptr(unsafe.Pointer(msg)), uintptr(flags), 0, 0, 0)
+	if e != 0 {
+		err = e
+	}
+	return
+}
+
+func sendmsg(s int, msg *Msghdr, flags int) (n int, err error) {
+	n, e := socketcall(_SENDMSG, uintptr(s), uintptr(unsafe.Pointer(msg)), uintptr(flags), 0, 0, 0)
+	if e != 0 {
+		err = e
+	}
+	return
+}
+
+func Listen(s int, n int) (err error) {
+	_, e := socketcall(_LISTEN, uintptr(s), uintptr(n), 0, 0, 0, 0)
+	if e != 0 {
+		err = e
+	}
+	return
+}
+
+func Shutdown(s, how int) (err error) {
+	_, e := socketcall(_SHUTDOWN, uintptr(s), uintptr(how), 0, 0, 0, 0)
+	if e != 0 {
+		err = e
+	}
+	return
+}
+
+func (r *PtraceRegs) PC() uint64 { return r.Psw.Addr }
+
+func (r *PtraceRegs) SetPC(pc uint64) { r.Psw.Addr = pc }
+
+func (iov *Iovec) SetLen(length int) {
+	iov.Len = uint64(length)
+}
+
+func (msghdr *Msghdr) SetControllen(length int) {
+	msghdr.Controllen = uint64(length)
+}
+
+func (cmsg *Cmsghdr) SetLen(length int) {
+	cmsg.Len = uint64(length)
+}

src/syscall/types_linux.go

@@ -77,8 +77,8 @@ struct sockaddr_any {
 // copied from /usr/include/linux/un.h
 struct my_sockaddr_un {
 	sa_family_t sun_family;
-#if defined(__ARM_EABI__) || defined(__powerpc64__)
-	// on ARM and PPC char is by default unsigned
+#if defined(__ARM_EABI__) || defined(__powerpc64__) || defined(__s390x__)
+	// on ARM, PPC and s390x char is by default unsigned
 	signed char sun_path[108];
 #else
 	char sun_path[108];
@@ -93,10 +93,22 @@ typedef struct user_pt_regs PtraceRegs;
 typedef struct pt_regs PtraceRegs;
 #elif defined(__mips__)
 typedef struct user PtraceRegs;
+#elif defined(__s390x__)
+typedef struct _user_regs_struct PtraceRegs;
 #else
 typedef struct user_regs_struct PtraceRegs;
 #endif
 
+#if defined(__s390x__)
+typedef struct _user_psw_struct ptracePsw;
+typedef struct _user_fpregs_struct ptraceFpregs;
+typedef struct _user_per_struct ptracePer;
+#else
+typedef struct {} ptracePsw;
+typedef struct {} ptraceFpregs;
+typedef struct {} ptracePer;
+#endif
+
 // The real epoll_event is a union, and godefs doesn't handle it well.
 struct my_epoll_event {
 	uint32_t events;
@@ -367,6 +379,13 @@ const SizeofInotifyEvent = C.sizeof_struct_inotify_event
 // Register structures
 type PtraceRegs C.PtraceRegs
 
+// Structures contained in PtraceRegs on s390x (exported by post.go)
+type ptracePsw C.ptracePsw
+
+type ptraceFpregs C.ptraceFpregs
+
+type ptracePer C.ptracePer
+
 // Misc
 
 type FdSet C.fd_set