src/pkg/syscall/syscall_plan9.go - go - Git at Google

 // Copyright 2011 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.

 // Plan 9 system calls.
 // This file is compiled as ordinary Go code,
 // but it is also input to mksyscall,
 // which parses the //sys lines and generates system call stubs.
 // Note that sometimes we use a lowercase //sys name and
 // wrap it in our own nicer implementation.

 package syscall

 import "unsafe"

 const ImplementsGetwd = true

 // ErrorString implements Error's String method by returning itself.
 type ErrorString string

 func (e ErrorString) Error() string { return string(e) }

 // NewError converts s to an ErrorString, which satisfies the Error interface.
 func NewError(s string) error { return ErrorString(s) }

 func (e ErrorString) Temporary() bool {
 	return e == EINTR || e == EMFILE || e.Timeout()
 }

 func (e ErrorString) Timeout() bool {
 	return e == EBUSY || e == ETIMEDOUT
 }

 // A Note is a string describing a process note.
 // It implements the os.Signal interface.
 type Note string

 func (n Note) Signal() {}

 func (n Note) String() string {
 	return string(n)
 }

 var (
 	Stdin  = 0
 	Stdout = 1
 	Stderr = 2
 )

 // For testing: clients can set this flag to force
 // creation of IPv6 sockets to return EAFNOSUPPORT.
 var SocketDisableIPv6 bool

 // Pointers passed to syscalls must not escape (be accessed by OS after the syscall returns).
 // For heap objects this will break when/if we have moving GC.
 // And for other objects (global, C allocated) go:noescape has no effect.

 //go:noescape

 func Syscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err ErrorString)

 //go:noescape

 func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err ErrorString)

 //go:noescape

 func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2, err uintptr)

 //go:noescape

 func RawSyscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr)

 func atoi(b []byte) (n uint) {
 	n = 0
 	for i := 0; i < len(b); i++ {
 		n = n*10 + uint(b[i]-'0')
 	}
 	return
 }

 func cstring(s []byte) string {
 	for i := range s {
 		if s[i] == 0 {
 			return string(s[0:i])
 		}
 	}
 	return string(s)
 }

 func errstr() string {
 	var buf [ERRMAX]byte

 	RawSyscall(SYS_ERRSTR, uintptr(unsafe.Pointer(&buf[0])), uintptr(len(buf)), 0)

 	buf[len(buf)-1] = 0
 	return cstring(buf[:])
 }

 // Implemented in assembly to import from runtime.
 func exit(int)

 func Exit(code int) { exit(code) }

 func readnum(path string) (uint, error) {
 	var b [12]byte

 	fd, e := Open(path, O_RDONLY)
 	if e != nil {
 		return 0, e
 	}
 	defer Close(fd)

 	n, e := Pread(fd, b[:], 0)

 	if e != nil {
 		return 0, e
 	}

 	m := 0
 	for ; m < n && b[m] == ' '; m++ {
 	}

 	return atoi(b[m : n-1]), nil
 }

 func Getpid() (pid int) {
 	n, _ := readnum("#c/pid")
 	return int(n)
 }

 func Getppid() (ppid int) {
 	n, _ := readnum("#c/ppid")
 	return int(n)
 }

 func Read(fd int, p []byte) (n int, err error) {
 	return Pread(fd, p, -1)
 }

 func Write(fd int, p []byte) (n int, err error) {
 	return Pwrite(fd, p, -1)
 }

 var ioSync int64

 func Getwd() (wd string, err error) {
 	fd, e := Open(".", O_RDONLY)

 	if e != nil {
 		return "", e
 	}
 	defer Close(fd)

 	return Fd2path(fd)
 }

 //sys	fd2path(fd int, buf []byte) (err error)
 func Fd2path(fd int) (path string, err error) {
 	var buf [512]byte

 	e := fd2path(fd, buf[:])
 	if e != nil {
 		return "", e
 	}
 	return cstring(buf[:]), nil
 }

 //sys	pipe(p *[2]_C_int) (err error)
 func Pipe(p []int) (err error) {
 	if len(p) != 2 {
 		return NewError("bad arg in system call")
 	}
 	var pp [2]_C_int
 	err = pipe(&pp)
 	p[0] = int(pp[0])
 	p[1] = int(pp[1])
 	return
 }

 // Underlying system call writes to newoffset via pointer.
 // Implemented in assembly to avoid allocation.
 func seek(placeholder uintptr, fd int, offset int64, whence int) (newoffset int64, err string)

 func Seek(fd int, offset int64, whence int) (newoffset int64, err error) {
 	newoffset, e := seek(0, fd, offset, whence)

 	if newoffset == -1 {
 		err = NewError(e)
 	}
 	return
 }

 func Mkdir(path string, mode uint32) (err error) {
 	fd, err := Create(path, O_RDONLY, DMDIR|mode)

 	if fd != -1 {
 		Close(fd)
 	}

 	return
 }

 type Waitmsg struct {
 	Pid  int
 	Time [3]uint32
 	Msg  string
 }

 func (w Waitmsg) Exited() bool   { return true }
 func (w Waitmsg) Signaled() bool { return false }

 func (w Waitmsg) ExitStatus() int {
 	if len(w.Msg) == 0 {
 		// a normal exit returns no message
 		return 0
 	}
 	return 1
 }

 //sys	await(s []byte) (n int, err error)
 func Await(w *Waitmsg) (err error) {
 	var buf [512]byte
 	var f [5][]byte

 	n, err := await(buf[:])

 	if err != nil || w == nil {
 		return
 	}

 	nf := 0
 	p := 0
 	for i := 0; i < n && nf < len(f)-1; i++ {
 		if buf[i] == ' ' {
 			f[nf] = buf[p:i]
 			p = i + 1
 			nf++
 		}
 	}
 	f[nf] = buf[p:]
 	nf++

 	if nf != len(f) {
 		return NewError("invalid wait message")
 	}
 	w.Pid = int(atoi(f[0]))
 	w.Time[0] = uint32(atoi(f[1]))
 	w.Time[1] = uint32(atoi(f[2]))
 	w.Time[2] = uint32(atoi(f[3]))
 	w.Msg = cstring(f[4])
 	if w.Msg == "''" {
 		// await() returns '' for no error
 		w.Msg = ""
 	}
 	return
 }

 func Unmount(name, old string) (err error) {
 	oldp, err := BytePtrFromString(old)
 	if err != nil {
 		return err
 	}
 	oldptr := uintptr(unsafe.Pointer(oldp))

 	var r0 uintptr
 	var e ErrorString

 	// bind(2) man page: If name is zero, everything bound or mounted upon old is unbound or unmounted.
 	if name == "" {
 		r0, _, e = Syscall(SYS_UNMOUNT, _zero, oldptr, 0)
 	} else {
 		namep, err := BytePtrFromString(name)
 		if err != nil {
 			return err
 		}
 		r0, _, e = Syscall(SYS_UNMOUNT, uintptr(unsafe.Pointer(namep)), oldptr, 0)
 	}

 	if int32(r0) == -1 {
 		err = e
 	}
 	return
 }

 func Fchdir(fd int) (err error) {
 	path, err := Fd2path(fd)

 	if err != nil {
 		return
 	}

 	return Chdir(path)
 }

 type Timespec struct {
 	Sec  int32
 	Nsec int32
 }

 type Timeval struct {
 	Sec  int32
 	Usec int32
 }

 func NsecToTimeval(nsec int64) (tv Timeval) {
 	nsec += 999 // round up to microsecond
 	tv.Usec = int32(nsec % 1e9 / 1e3)
 	tv.Sec = int32(nsec / 1e9)
 	return
 }

 func DecodeBintime(b []byte) (nsec int64, err error) {
 	if len(b) != 8 {
 		return -1, NewError("bad /dev/bintime format")
 	}
 	nsec = int64(b[0])<<56 |
 		int64(b[1])<<48 |
 		int64(b[2])<<40 |
 		int64(b[3])<<32 |
 		int64(b[4])<<24 |
 		int64(b[5])<<16 |
 		int64(b[6])<<8 |
 		int64(b[7])
 	return
 }

 func Gettimeofday(tv *Timeval) error {
 	nsec, e := nanotime()
 	if e != nil {
 		return e
 	}
 	*tv = NsecToTimeval(nsec)
 	return e
 }

 func Getegid() (egid int) { return -1 }
 func Geteuid() (euid int) { return -1 }
 func Getgid() (gid int)   { return -1 }
 func Getuid() (uid int)   { return -1 }

 func Getgroups() (gids []int, err error) {
 	return make([]int, 0), nil
 }

 //sys	Dup(oldfd int, newfd int) (fd int, err error)
 //sys	Open(path string, mode int) (fd int, err error)
 //sys	Create(path string, mode int, perm uint32) (fd int, err error)
 //sys	Remove(path string) (err error)
 //sys	Pread(fd int, p []byte, offset int64) (n int, err error)
 //sys	Pwrite(fd int, p []byte, offset int64) (n int, err error)
 //sys	Close(fd int) (err error)
 //sys	Chdir(path string) (err error)
 //sys	Bind(name string, old string, flag int) (err error)
 //sys	Mount(fd int, afd int, old string, flag int, aname string) (err error)
 //sys	Stat(path string, edir []byte) (n int, err error)
 //sys	Fstat(fd int, edir []byte) (n int, err error)
 //sys	Wstat(path string, edir []byte) (err error)
 //sys	Fwstat(fd int, edir []byte) (err error)
	// Copyright 2011 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.

	// Plan 9 system calls.
	// This file is compiled as ordinary Go code,
	// but it is also input to mksyscall,
	// which parses the //sys lines and generates system call stubs.
	// Note that sometimes we use a lowercase //sys name and
	// wrap it in our own nicer implementation.

	package syscall

	import "unsafe"

	const ImplementsGetwd = true

	// ErrorString implements Error's String method by returning itself.
	type ErrorString string

	func (e ErrorString) Error() string { return string(e) }

	// NewError converts s to an ErrorString, which satisfies the Error interface.
	func NewError(s string) error { return ErrorString(s) }

	func (e ErrorString) Temporary() bool {
	return e == EINTR \|\| e == EMFILE \|\| e.Timeout()
	}

	func (e ErrorString) Timeout() bool {
	return e == EBUSY \|\| e == ETIMEDOUT
	}

	// A Note is a string describing a process note.
	// It implements the os.Signal interface.
	type Note string

	func (n Note) Signal() {}

	func (n Note) String() string {
	return string(n)
	}

	var (
	Stdin = 0
	Stdout = 1
	Stderr = 2
	)

	// For testing: clients can set this flag to force
	// creation of IPv6 sockets to return EAFNOSUPPORT.
	var SocketDisableIPv6 bool

	// Pointers passed to syscalls must not escape (be accessed by OS after the syscall returns).
	// For heap objects this will break when/if we have moving GC.
	// And for other objects (global, C allocated) go:noescape has no effect.

	//go:noescape

	func Syscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err ErrorString)

	//go:noescape

	func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err ErrorString)

	//go:noescape

	func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2, err uintptr)

	//go:noescape

	func RawSyscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr)

	func atoi(b []byte) (n uint) {
	n = 0
	for i := 0; i < len(b); i++ {
	n = n*10 + uint(b[i]-'0')
	}
	return
	}

	func cstring(s []byte) string {
	for i := range s {
	if s[i] == 0 {
	return string(s[0:i])
	}
	}
	return string(s)
	}

	func errstr() string {
	var buf [ERRMAX]byte

	RawSyscall(SYS_ERRSTR, uintptr(unsafe.Pointer(&buf[0])), uintptr(len(buf)), 0)

	buf[len(buf)-1] = 0
	return cstring(buf[:])
	}

	// Implemented in assembly to import from runtime.
	func exit(int)

	func Exit(code int) { exit(code) }

	func readnum(path string) (uint, error) {
	var b [12]byte

	fd, e := Open(path, O_RDONLY)
	if e != nil {
	return 0, e
	}
	defer Close(fd)

	n, e := Pread(fd, b[:], 0)

	if e != nil {
	return 0, e
	}

	m := 0
	for ; m < n && b[m] == ' '; m++ {
	}

	return atoi(b[m : n-1]), nil
	}

	func Getpid() (pid int) {
	n, _ := readnum("#c/pid")
	return int(n)
	}

	func Getppid() (ppid int) {
	n, _ := readnum("#c/ppid")
	return int(n)
	}

	func Read(fd int, p []byte) (n int, err error) {
	return Pread(fd, p, -1)
	}

	func Write(fd int, p []byte) (n int, err error) {
	return Pwrite(fd, p, -1)
	}

	var ioSync int64

	func Getwd() (wd string, err error) {
	fd, e := Open(".", O_RDONLY)

	if e != nil {
	return "", e
	}
	defer Close(fd)

	return Fd2path(fd)
	}

	//sys fd2path(fd int, buf []byte) (err error)
	func Fd2path(fd int) (path string, err error) {
	var buf [512]byte

	e := fd2path(fd, buf[:])
	if e != nil {
	return "", e
	}
	return cstring(buf[:]), nil
	}

	//sys pipe(p *[2]_C_int) (err error)
	func Pipe(p []int) (err error) {
	if len(p) != 2 {
	return NewError("bad arg in system call")
	}
	var pp [2]_C_int
	err = pipe(&pp)
	p[0] = int(pp[0])
	p[1] = int(pp[1])
	return
	}

	// Underlying system call writes to newoffset via pointer.
	// Implemented in assembly to avoid allocation.
	func seek(placeholder uintptr, fd int, offset int64, whence int) (newoffset int64, err string)

	func Seek(fd int, offset int64, whence int) (newoffset int64, err error) {
	newoffset, e := seek(0, fd, offset, whence)

	if newoffset == -1 {
	err = NewError(e)
	}
	return
	}

	func Mkdir(path string, mode uint32) (err error) {
	fd, err := Create(path, O_RDONLY, DMDIR\|mode)

	if fd != -1 {
	Close(fd)
	}

	return
	}

	type Waitmsg struct {
	Pid int
	Time [3]uint32
	Msg string
	}

	func (w Waitmsg) Exited() bool { return true }
	func (w Waitmsg) Signaled() bool { return false }

	func (w Waitmsg) ExitStatus() int {
	if len(w.Msg) == 0 {
	// a normal exit returns no message
	return 0
	}
	return 1
	}

	//sys await(s []byte) (n int, err error)
	func Await(w *Waitmsg) (err error) {
	var buf [512]byte
	var f [5][]byte

	n, err := await(buf[:])

	if err != nil \|\| w == nil {
	return
	}

	nf := 0
	p := 0
	for i := 0; i < n && nf < len(f)-1; i++ {
	if buf[i] == ' ' {
	f[nf] = buf[p:i]
	p = i + 1
	nf++
	}
	}
	f[nf] = buf[p:]
	nf++

	if nf != len(f) {
	return NewError("invalid wait message")
	}
	w.Pid = int(atoi(f[0]))
	w.Time[0] = uint32(atoi(f[1]))
	w.Time[1] = uint32(atoi(f[2]))
	w.Time[2] = uint32(atoi(f[3]))
	w.Msg = cstring(f[4])
	if w.Msg == "''" {
	// await() returns '' for no error
	w.Msg = ""
	}
	return
	}

	func Unmount(name, old string) (err error) {
	oldp, err := BytePtrFromString(old)
	if err != nil {
	return err
	}
	oldptr := uintptr(unsafe.Pointer(oldp))

	var r0 uintptr
	var e ErrorString

	// bind(2) man page: If name is zero, everything bound or mounted upon old is unbound or unmounted.
	if name == "" {
	r0, _, e = Syscall(SYS_UNMOUNT, _zero, oldptr, 0)
	} else {
	namep, err := BytePtrFromString(name)
	if err != nil {
	return err
	}
	r0, _, e = Syscall(SYS_UNMOUNT, uintptr(unsafe.Pointer(namep)), oldptr, 0)
	}

	if int32(r0) == -1 {
	err = e
	}
	return
	}

	func Fchdir(fd int) (err error) {
	path, err := Fd2path(fd)

	if err != nil {
	return
	}

	return Chdir(path)
	}

	type Timespec struct {
	Sec int32
	Nsec int32
	}

	type Timeval struct {
	Sec int32
	Usec int32
	}

	func NsecToTimeval(nsec int64) (tv Timeval) {
	nsec += 999 // round up to microsecond
	tv.Usec = int32(nsec % 1e9 / 1e3)
	tv.Sec = int32(nsec / 1e9)
	return
	}

	func DecodeBintime(b []byte) (nsec int64, err error) {
	if len(b) != 8 {
	return -1, NewError("bad /dev/bintime format")
	}
	nsec = int64(b[0])<<56 \|
	int64(b[1])<<48 \|
	int64(b[2])<<40 \|
	int64(b[3])<<32 \|
	int64(b[4])<<24 \|
	int64(b[5])<<16 \|
	int64(b[6])<<8 \|
	int64(b[7])
	return
	}

	func Gettimeofday(tv *Timeval) error {
	nsec, e := nanotime()
	if e != nil {
	return e
	}
	*tv = NsecToTimeval(nsec)
	return e
	}

	func Getegid() (egid int) { return -1 }
	func Geteuid() (euid int) { return -1 }
	func Getgid() (gid int) { return -1 }
	func Getuid() (uid int) { return -1 }

	func Getgroups() (gids []int, err error) {
	return make([]int, 0), nil
	}

	//sys Dup(oldfd int, newfd int) (fd int, err error)
	//sys Open(path string, mode int) (fd int, err error)
	//sys Create(path string, mode int, perm uint32) (fd int, err error)
	//sys Remove(path string) (err error)
	//sys Pread(fd int, p []byte, offset int64) (n int, err error)
	//sys Pwrite(fd int, p []byte, offset int64) (n int, err error)
	//sys Close(fd int) (err error)
	//sys Chdir(path string) (err error)
	//sys Bind(name string, old string, flag int) (err error)
	//sys Mount(fd int, afd int, old string, flag int, aname string) (err error)
	//sys Stat(path string, edir []byte) (n int, err error)
	//sys Fstat(fd int, edir []byte) (n int, err error)
	//sys Wstat(path string, edir []byte) (err error)
	//sys Fwstat(fd int, edir []byte) (err error)