1// Copyright 2009 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5// Linux system calls.
6// This file is compiled as ordinary Go code,
7// but it is also input to mksyscall,
8// which parses the //sys lines and generates system call stubs.
9// Note that sometimes we use a lowercase //sys name and
10// wrap it in our own nicer implementation.
11
12package unix
13
14import (
15	"syscall"
16	"unsafe"
17)
18
19/*
20 * Wrapped
21 */
22
23func Access(path string, mode uint32) (err error) {
24	return Faccessat(AT_FDCWD, path, mode, 0)
25}
26
27func Chmod(path string, mode uint32) (err error) {
28	return Fchmodat(AT_FDCWD, path, mode, 0)
29}
30
31func Chown(path string, uid int, gid int) (err error) {
32	return Fchownat(AT_FDCWD, path, uid, gid, 0)
33}
34
35func Creat(path string, mode uint32) (fd int, err error) {
36	return Open(path, O_CREAT|O_WRONLY|O_TRUNC, mode)
37}
38
39//sys	fchmodat(dirfd int, path string, mode uint32) (err error)
40
41func Fchmodat(dirfd int, path string, mode uint32, flags int) (err error) {
42	// Linux fchmodat doesn't support the flags parameter. Mimick glibc's behavior
43	// and check the flags. Otherwise the mode would be applied to the symlink
44	// destination which is not what the user expects.
45	if flags&^AT_SYMLINK_NOFOLLOW != 0 {
46		return EINVAL
47	} else if flags&AT_SYMLINK_NOFOLLOW != 0 {
48		return EOPNOTSUPP
49	}
50	return fchmodat(dirfd, path, mode)
51}
52
53//sys	ioctl(fd int, req uint, arg uintptr) (err error)
54
55// ioctl itself should not be exposed directly, but additional get/set
56// functions for specific types are permissible.
57
58// IoctlSetInt performs an ioctl operation which sets an integer value
59// on fd, using the specified request number.
60func IoctlSetInt(fd int, req uint, value int) error {
61	return ioctl(fd, req, uintptr(value))
62}
63
64func IoctlSetWinsize(fd int, req uint, value *Winsize) error {
65	return ioctl(fd, req, uintptr(unsafe.Pointer(value)))
66}
67
68func IoctlSetTermios(fd int, req uint, value *Termios) error {
69	return ioctl(fd, req, uintptr(unsafe.Pointer(value)))
70}
71
72// IoctlGetInt performs an ioctl operation which gets an integer value
73// from fd, using the specified request number.
74func IoctlGetInt(fd int, req uint) (int, error) {
75	var value int
76	err := ioctl(fd, req, uintptr(unsafe.Pointer(&value)))
77	return value, err
78}
79
80func IoctlGetWinsize(fd int, req uint) (*Winsize, error) {
81	var value Winsize
82	err := ioctl(fd, req, uintptr(unsafe.Pointer(&value)))
83	return &value, err
84}
85
86func IoctlGetTermios(fd int, req uint) (*Termios, error) {
87	var value Termios
88	err := ioctl(fd, req, uintptr(unsafe.Pointer(&value)))
89	return &value, err
90}
91
92//sys	Linkat(olddirfd int, oldpath string, newdirfd int, newpath string, flags int) (err error)
93
94func Link(oldpath string, newpath string) (err error) {
95	return Linkat(AT_FDCWD, oldpath, AT_FDCWD, newpath, 0)
96}
97
98func Mkdir(path string, mode uint32) (err error) {
99	return Mkdirat(AT_FDCWD, path, mode)
100}
101
102func Mknod(path string, mode uint32, dev int) (err error) {
103	return Mknodat(AT_FDCWD, path, mode, dev)
104}
105
106func Open(path string, mode int, perm uint32) (fd int, err error) {
107	return openat(AT_FDCWD, path, mode|O_LARGEFILE, perm)
108}
109
110//sys	openat(dirfd int, path string, flags int, mode uint32) (fd int, err error)
111
112func Openat(dirfd int, path string, flags int, mode uint32) (fd int, err error) {
113	return openat(dirfd, path, flags|O_LARGEFILE, mode)
114}
115
116//sys	ppoll(fds *PollFd, nfds int, timeout *Timespec, sigmask *Sigset_t) (n int, err error)
117
118func Ppoll(fds []PollFd, timeout *Timespec, sigmask *Sigset_t) (n int, err error) {
119	if len(fds) == 0 {
120		return ppoll(nil, 0, timeout, sigmask)
121	}
122	return ppoll(&fds[0], len(fds), timeout, sigmask)
123}
124
125//sys	Readlinkat(dirfd int, path string, buf []byte) (n int, err error)
126
127func Readlink(path string, buf []byte) (n int, err error) {
128	return Readlinkat(AT_FDCWD, path, buf)
129}
130
131func Rename(oldpath string, newpath string) (err error) {
132	return Renameat(AT_FDCWD, oldpath, AT_FDCWD, newpath)
133}
134
135func Rmdir(path string) error {
136	return Unlinkat(AT_FDCWD, path, AT_REMOVEDIR)
137}
138
139//sys	Symlinkat(oldpath string, newdirfd int, newpath string) (err error)
140
141func Symlink(oldpath string, newpath string) (err error) {
142	return Symlinkat(oldpath, AT_FDCWD, newpath)
143}
144
145func Unlink(path string) error {
146	return Unlinkat(AT_FDCWD, path, 0)
147}
148
149//sys	Unlinkat(dirfd int, path string, flags int) (err error)
150
151//sys	utimes(path string, times *[2]Timeval) (err error)
152
153func Utimes(path string, tv []Timeval) error {
154	if tv == nil {
155		err := utimensat(AT_FDCWD, path, nil, 0)
156		if err != ENOSYS {
157			return err
158		}
159		return utimes(path, nil)
160	}
161	if len(tv) != 2 {
162		return EINVAL
163	}
164	var ts [2]Timespec
165	ts[0] = NsecToTimespec(TimevalToNsec(tv[0]))
166	ts[1] = NsecToTimespec(TimevalToNsec(tv[1]))
167	err := utimensat(AT_FDCWD, path, (*[2]Timespec)(unsafe.Pointer(&ts[0])), 0)
168	if err != ENOSYS {
169		return err
170	}
171	return utimes(path, (*[2]Timeval)(unsafe.Pointer(&tv[0])))
172}
173
174//sys	utimensat(dirfd int, path string, times *[2]Timespec, flags int) (err error)
175
176func UtimesNano(path string, ts []Timespec) error {
177	if ts == nil {
178		err := utimensat(AT_FDCWD, path, nil, 0)
179		if err != ENOSYS {
180			return err
181		}
182		return utimes(path, nil)
183	}
184	if len(ts) != 2 {
185		return EINVAL
186	}
187	err := utimensat(AT_FDCWD, path, (*[2]Timespec)(unsafe.Pointer(&ts[0])), 0)
188	if err != ENOSYS {
189		return err
190	}
191	// If the utimensat syscall isn't available (utimensat was added to Linux
192	// in 2.6.22, Released, 8 July 2007) then fall back to utimes
193	var tv [2]Timeval
194	for i := 0; i < 2; i++ {
195		tv[i] = NsecToTimeval(TimespecToNsec(ts[i]))
196	}
197	return utimes(path, (*[2]Timeval)(unsafe.Pointer(&tv[0])))
198}
199
200func UtimesNanoAt(dirfd int, path string, ts []Timespec, flags int) error {
201	if ts == nil {
202		return utimensat(dirfd, path, nil, flags)
203	}
204	if len(ts) != 2 {
205		return EINVAL
206	}
207	return utimensat(dirfd, path, (*[2]Timespec)(unsafe.Pointer(&ts[0])), flags)
208}
209
210//sys	futimesat(dirfd int, path *byte, times *[2]Timeval) (err error)
211
212func Futimesat(dirfd int, path string, tv []Timeval) error {
213	pathp, err := BytePtrFromString(path)
214	if err != nil {
215		return err
216	}
217	if tv == nil {
218		return futimesat(dirfd, pathp, nil)
219	}
220	if len(tv) != 2 {
221		return EINVAL
222	}
223	return futimesat(dirfd, pathp, (*[2]Timeval)(unsafe.Pointer(&tv[0])))
224}
225
226func Futimes(fd int, tv []Timeval) (err error) {
227	// Believe it or not, this is the best we can do on Linux
228	// (and is what glibc does).
229	return Utimes("/proc/self/fd/"+itoa(fd), tv)
230}
231
232const ImplementsGetwd = true
233
234//sys	Getcwd(buf []byte) (n int, err error)
235
236func Getwd() (wd string, err error) {
237	var buf [PathMax]byte
238	n, err := Getcwd(buf[0:])
239	if err != nil {
240		return "", err
241	}
242	// Getcwd returns the number of bytes written to buf, including the NUL.
243	if n < 1 || n > len(buf) || buf[n-1] != 0 {
244		return "", EINVAL
245	}
246	return string(buf[0 : n-1]), nil
247}
248
249func Getgroups() (gids []int, err error) {
250	n, err := getgroups(0, nil)
251	if err != nil {
252		return nil, err
253	}
254	if n == 0 {
255		return nil, nil
256	}
257
258	// Sanity check group count. Max is 1<<16 on Linux.
259	if n < 0 || n > 1<<20 {
260		return nil, EINVAL
261	}
262
263	a := make([]_Gid_t, n)
264	n, err = getgroups(n, &a[0])
265	if err != nil {
266		return nil, err
267	}
268	gids = make([]int, n)
269	for i, v := range a[0:n] {
270		gids[i] = int(v)
271	}
272	return
273}
274
275func Setgroups(gids []int) (err error) {
276	if len(gids) == 0 {
277		return setgroups(0, nil)
278	}
279
280	a := make([]_Gid_t, len(gids))
281	for i, v := range gids {
282		a[i] = _Gid_t(v)
283	}
284	return setgroups(len(a), &a[0])
285}
286
287type WaitStatus uint32
288
289// Wait status is 7 bits at bottom, either 0 (exited),
290// 0x7F (stopped), or a signal number that caused an exit.
291// The 0x80 bit is whether there was a core dump.
292// An extra number (exit code, signal causing a stop)
293// is in the high bits. At least that's the idea.
294// There are various irregularities. For example, the
295// "continued" status is 0xFFFF, distinguishing itself
296// from stopped via the core dump bit.
297
298const (
299	mask    = 0x7F
300	core    = 0x80
301	exited  = 0x00
302	stopped = 0x7F
303	shift   = 8
304)
305
306func (w WaitStatus) Exited() bool { return w&mask == exited }
307
308func (w WaitStatus) Signaled() bool { return w&mask != stopped && w&mask != exited }
309
310func (w WaitStatus) Stopped() bool { return w&0xFF == stopped }
311
312func (w WaitStatus) Continued() bool { return w == 0xFFFF }
313
314func (w WaitStatus) CoreDump() bool { return w.Signaled() && w&core != 0 }
315
316func (w WaitStatus) ExitStatus() int {
317	if !w.Exited() {
318		return -1
319	}
320	return int(w>>shift) & 0xFF
321}
322
323func (w WaitStatus) Signal() syscall.Signal {
324	if !w.Signaled() {
325		return -1
326	}
327	return syscall.Signal(w & mask)
328}
329
330func (w WaitStatus) StopSignal() syscall.Signal {
331	if !w.Stopped() {
332		return -1
333	}
334	return syscall.Signal(w>>shift) & 0xFF
335}
336
337func (w WaitStatus) TrapCause() int {
338	if w.StopSignal() != SIGTRAP {
339		return -1
340	}
341	return int(w>>shift) >> 8
342}
343
344//sys	wait4(pid int, wstatus *_C_int, options int, rusage *Rusage) (wpid int, err error)
345
346func Wait4(pid int, wstatus *WaitStatus, options int, rusage *Rusage) (wpid int, err error) {
347	var status _C_int
348	wpid, err = wait4(pid, &status, options, rusage)
349	if wstatus != nil {
350		*wstatus = WaitStatus(status)
351	}
352	return
353}
354
355func Mkfifo(path string, mode uint32) error {
356	return Mknod(path, mode|S_IFIFO, 0)
357}
358
359func Mkfifoat(dirfd int, path string, mode uint32) error {
360	return Mknodat(dirfd, path, mode|S_IFIFO, 0)
361}
362
363func (sa *SockaddrInet4) sockaddr() (unsafe.Pointer, _Socklen, error) {
364	if sa.Port < 0 || sa.Port > 0xFFFF {
365		return nil, 0, EINVAL
366	}
367	sa.raw.Family = AF_INET
368	p := (*[2]byte)(unsafe.Pointer(&sa.raw.Port))
369	p[0] = byte(sa.Port >> 8)
370	p[1] = byte(sa.Port)
371	for i := 0; i < len(sa.Addr); i++ {
372		sa.raw.Addr[i] = sa.Addr[i]
373	}
374	return unsafe.Pointer(&sa.raw), SizeofSockaddrInet4, nil
375}
376
377func (sa *SockaddrInet6) sockaddr() (unsafe.Pointer, _Socklen, error) {
378	if sa.Port < 0 || sa.Port > 0xFFFF {
379		return nil, 0, EINVAL
380	}
381	sa.raw.Family = AF_INET6
382	p := (*[2]byte)(unsafe.Pointer(&sa.raw.Port))
383	p[0] = byte(sa.Port >> 8)
384	p[1] = byte(sa.Port)
385	sa.raw.Scope_id = sa.ZoneId
386	for i := 0; i < len(sa.Addr); i++ {
387		sa.raw.Addr[i] = sa.Addr[i]
388	}
389	return unsafe.Pointer(&sa.raw), SizeofSockaddrInet6, nil
390}
391
392func (sa *SockaddrUnix) sockaddr() (unsafe.Pointer, _Socklen, error) {
393	name := sa.Name
394	n := len(name)
395	if n >= len(sa.raw.Path) {
396		return nil, 0, EINVAL
397	}
398	sa.raw.Family = AF_UNIX
399	for i := 0; i < n; i++ {
400		sa.raw.Path[i] = int8(name[i])
401	}
402	// length is family (uint16), name, NUL.
403	sl := _Socklen(2)
404	if n > 0 {
405		sl += _Socklen(n) + 1
406	}
407	if sa.raw.Path[0] == '@' {
408		sa.raw.Path[0] = 0
409		// Don't count trailing NUL for abstract address.
410		sl--
411	}
412
413	return unsafe.Pointer(&sa.raw), sl, nil
414}
415
416// SockaddrLinklayer implements the Sockaddr interface for AF_PACKET type sockets.
417type SockaddrLinklayer struct {
418	Protocol uint16
419	Ifindex  int
420	Hatype   uint16
421	Pkttype  uint8
422	Halen    uint8
423	Addr     [8]byte
424	raw      RawSockaddrLinklayer
425}
426
427func (sa *SockaddrLinklayer) sockaddr() (unsafe.Pointer, _Socklen, error) {
428	if sa.Ifindex < 0 || sa.Ifindex > 0x7fffffff {
429		return nil, 0, EINVAL
430	}
431	sa.raw.Family = AF_PACKET
432	sa.raw.Protocol = sa.Protocol
433	sa.raw.Ifindex = int32(sa.Ifindex)
434	sa.raw.Hatype = sa.Hatype
435	sa.raw.Pkttype = sa.Pkttype
436	sa.raw.Halen = sa.Halen
437	for i := 0; i < len(sa.Addr); i++ {
438		sa.raw.Addr[i] = sa.Addr[i]
439	}
440	return unsafe.Pointer(&sa.raw), SizeofSockaddrLinklayer, nil
441}
442
443// SockaddrNetlink implements the Sockaddr interface for AF_NETLINK type sockets.
444type SockaddrNetlink struct {
445	Family uint16
446	Pad    uint16
447	Pid    uint32
448	Groups uint32
449	raw    RawSockaddrNetlink
450}
451
452func (sa *SockaddrNetlink) sockaddr() (unsafe.Pointer, _Socklen, error) {
453	sa.raw.Family = AF_NETLINK
454	sa.raw.Pad = sa.Pad
455	sa.raw.Pid = sa.Pid
456	sa.raw.Groups = sa.Groups
457	return unsafe.Pointer(&sa.raw), SizeofSockaddrNetlink, nil
458}
459
460// SockaddrHCI implements the Sockaddr interface for AF_BLUETOOTH type sockets
461// using the HCI protocol.
462type SockaddrHCI struct {
463	Dev     uint16
464	Channel uint16
465	raw     RawSockaddrHCI
466}
467
468func (sa *SockaddrHCI) sockaddr() (unsafe.Pointer, _Socklen, error) {
469	sa.raw.Family = AF_BLUETOOTH
470	sa.raw.Dev = sa.Dev
471	sa.raw.Channel = sa.Channel
472	return unsafe.Pointer(&sa.raw), SizeofSockaddrHCI, nil
473}
474
475// SockaddrL2 implements the Sockaddr interface for AF_BLUETOOTH type sockets
476// using the L2CAP protocol.
477type SockaddrL2 struct {
478	PSM      uint16
479	CID      uint16
480	Addr     [6]uint8
481	AddrType uint8
482	raw      RawSockaddrL2
483}
484
485func (sa *SockaddrL2) sockaddr() (unsafe.Pointer, _Socklen, error) {
486	sa.raw.Family = AF_BLUETOOTH
487	psm := (*[2]byte)(unsafe.Pointer(&sa.raw.Psm))
488	psm[0] = byte(sa.PSM)
489	psm[1] = byte(sa.PSM >> 8)
490	for i := 0; i < len(sa.Addr); i++ {
491		sa.raw.Bdaddr[i] = sa.Addr[len(sa.Addr)-1-i]
492	}
493	cid := (*[2]byte)(unsafe.Pointer(&sa.raw.Cid))
494	cid[0] = byte(sa.CID)
495	cid[1] = byte(sa.CID >> 8)
496	sa.raw.Bdaddr_type = sa.AddrType
497	return unsafe.Pointer(&sa.raw), SizeofSockaddrL2, nil
498}
499
500// SockaddrCAN implements the Sockaddr interface for AF_CAN type sockets.
501// The RxID and TxID fields are used for transport protocol addressing in
502// (CAN_TP16, CAN_TP20, CAN_MCNET, and CAN_ISOTP), they can be left with
503// zero values for CAN_RAW and CAN_BCM sockets as they have no meaning.
504//
505// The SockaddrCAN struct must be bound to the socket file descriptor
506// using Bind before the CAN socket can be used.
507//
508//      // Read one raw CAN frame
509//      fd, _ := Socket(AF_CAN, SOCK_RAW, CAN_RAW)
510//      addr := &SockaddrCAN{Ifindex: index}
511//      Bind(fd, addr)
512//      frame := make([]byte, 16)
513//      Read(fd, frame)
514//
515// The full SocketCAN documentation can be found in the linux kernel
516// archives at: https://www.kernel.org/doc/Documentation/networking/can.txt
517type SockaddrCAN struct {
518	Ifindex int
519	RxID    uint32
520	TxID    uint32
521	raw     RawSockaddrCAN
522}
523
524func (sa *SockaddrCAN) sockaddr() (unsafe.Pointer, _Socklen, error) {
525	if sa.Ifindex < 0 || sa.Ifindex > 0x7fffffff {
526		return nil, 0, EINVAL
527	}
528	sa.raw.Family = AF_CAN
529	sa.raw.Ifindex = int32(sa.Ifindex)
530	rx := (*[4]byte)(unsafe.Pointer(&sa.RxID))
531	for i := 0; i < 4; i++ {
532		sa.raw.Addr[i] = rx[i]
533	}
534	tx := (*[4]byte)(unsafe.Pointer(&sa.TxID))
535	for i := 0; i < 4; i++ {
536		sa.raw.Addr[i+4] = tx[i]
537	}
538	return unsafe.Pointer(&sa.raw), SizeofSockaddrCAN, nil
539}
540
541// SockaddrALG implements the Sockaddr interface for AF_ALG type sockets.
542// SockaddrALG enables userspace access to the Linux kernel's cryptography
543// subsystem. The Type and Name fields specify which type of hash or cipher
544// should be used with a given socket.
545//
546// To create a file descriptor that provides access to a hash or cipher, both
547// Bind and Accept must be used. Once the setup process is complete, input
548// data can be written to the socket, processed by the kernel, and then read
549// back as hash output or ciphertext.
550//
551// Here is an example of using an AF_ALG socket with SHA1 hashing.
552// The initial socket setup process is as follows:
553//
554//      // Open a socket to perform SHA1 hashing.
555//      fd, _ := unix.Socket(unix.AF_ALG, unix.SOCK_SEQPACKET, 0)
556//      addr := &unix.SockaddrALG{Type: "hash", Name: "sha1"}
557//      unix.Bind(fd, addr)
558//      // Note: unix.Accept does not work at this time; must invoke accept()
559//      // manually using unix.Syscall.
560//      hashfd, _, _ := unix.Syscall(unix.SYS_ACCEPT, uintptr(fd), 0, 0)
561//
562// Once a file descriptor has been returned from Accept, it may be used to
563// perform SHA1 hashing. The descriptor is not safe for concurrent use, but
564// may be re-used repeatedly with subsequent Write and Read operations.
565//
566// When hashing a small byte slice or string, a single Write and Read may
567// be used:
568//
569//      // Assume hashfd is already configured using the setup process.
570//      hash := os.NewFile(hashfd, "sha1")
571//      // Hash an input string and read the results. Each Write discards
572//      // previous hash state. Read always reads the current state.
573//      b := make([]byte, 20)
574//      for i := 0; i < 2; i++ {
575//          io.WriteString(hash, "Hello, world.")
576//          hash.Read(b)
577//          fmt.Println(hex.EncodeToString(b))
578//      }
579//      // Output:
580//      // 2ae01472317d1935a84797ec1983ae243fc6aa28
581//      // 2ae01472317d1935a84797ec1983ae243fc6aa28
582//
583// For hashing larger byte slices, or byte streams such as those read from
584// a file or socket, use Sendto with MSG_MORE to instruct the kernel to update
585// the hash digest instead of creating a new one for a given chunk and finalizing it.
586//
587//      // Assume hashfd and addr are already configured using the setup process.
588//      hash := os.NewFile(hashfd, "sha1")
589//      // Hash the contents of a file.
590//      f, _ := os.Open("/tmp/linux-4.10-rc7.tar.xz")
591//      b := make([]byte, 4096)
592//      for {
593//          n, err := f.Read(b)
594//          if err == io.EOF {
595//              break
596//          }
597//          unix.Sendto(hashfd, b[:n], unix.MSG_MORE, addr)
598//      }
599//      hash.Read(b)
600//      fmt.Println(hex.EncodeToString(b))
601//      // Output: 85cdcad0c06eef66f805ecce353bec9accbeecc5
602//
603// For more information, see: http://www.chronox.de/crypto-API/crypto/userspace-if.html.
604type SockaddrALG struct {
605	Type    string
606	Name    string
607	Feature uint32
608	Mask    uint32
609	raw     RawSockaddrALG
610}
611
612func (sa *SockaddrALG) sockaddr() (unsafe.Pointer, _Socklen, error) {
613	// Leave room for NUL byte terminator.
614	if len(sa.Type) > 13 {
615		return nil, 0, EINVAL
616	}
617	if len(sa.Name) > 63 {
618		return nil, 0, EINVAL
619	}
620
621	sa.raw.Family = AF_ALG
622	sa.raw.Feat = sa.Feature
623	sa.raw.Mask = sa.Mask
624
625	typ, err := ByteSliceFromString(sa.Type)
626	if err != nil {
627		return nil, 0, err
628	}
629	name, err := ByteSliceFromString(sa.Name)
630	if err != nil {
631		return nil, 0, err
632	}
633
634	copy(sa.raw.Type[:], typ)
635	copy(sa.raw.Name[:], name)
636
637	return unsafe.Pointer(&sa.raw), SizeofSockaddrALG, nil
638}
639
640// SockaddrVM implements the Sockaddr interface for AF_VSOCK type sockets.
641// SockaddrVM provides access to Linux VM sockets: a mechanism that enables
642// bidirectional communication between a hypervisor and its guest virtual
643// machines.
644type SockaddrVM struct {
645	// CID and Port specify a context ID and port address for a VM socket.
646	// Guests have a unique CID, and hosts may have a well-known CID of:
647	//  - VMADDR_CID_HYPERVISOR: refers to the hypervisor process.
648	//  - VMADDR_CID_HOST: refers to other processes on the host.
649	CID  uint32
650	Port uint32
651	raw  RawSockaddrVM
652}
653
654func (sa *SockaddrVM) sockaddr() (unsafe.Pointer, _Socklen, error) {
655	sa.raw.Family = AF_VSOCK
656	sa.raw.Port = sa.Port
657	sa.raw.Cid = sa.CID
658
659	return unsafe.Pointer(&sa.raw), SizeofSockaddrVM, nil
660}
661
662func anyToSockaddr(rsa *RawSockaddrAny) (Sockaddr, error) {
663	switch rsa.Addr.Family {
664	case AF_NETLINK:
665		pp := (*RawSockaddrNetlink)(unsafe.Pointer(rsa))
666		sa := new(SockaddrNetlink)
667		sa.Family = pp.Family
668		sa.Pad = pp.Pad
669		sa.Pid = pp.Pid
670		sa.Groups = pp.Groups
671		return sa, nil
672
673	case AF_PACKET:
674		pp := (*RawSockaddrLinklayer)(unsafe.Pointer(rsa))
675		sa := new(SockaddrLinklayer)
676		sa.Protocol = pp.Protocol
677		sa.Ifindex = int(pp.Ifindex)
678		sa.Hatype = pp.Hatype
679		sa.Pkttype = pp.Pkttype
680		sa.Halen = pp.Halen
681		for i := 0; i < len(sa.Addr); i++ {
682			sa.Addr[i] = pp.Addr[i]
683		}
684		return sa, nil
685
686	case AF_UNIX:
687		pp := (*RawSockaddrUnix)(unsafe.Pointer(rsa))
688		sa := new(SockaddrUnix)
689		if pp.Path[0] == 0 {
690			// "Abstract" Unix domain socket.
691			// Rewrite leading NUL as @ for textual display.
692			// (This is the standard convention.)
693			// Not friendly to overwrite in place,
694			// but the callers below don't care.
695			pp.Path[0] = '@'
696		}
697
698		// Assume path ends at NUL.
699		// This is not technically the Linux semantics for
700		// abstract Unix domain sockets--they are supposed
701		// to be uninterpreted fixed-size binary blobs--but
702		// everyone uses this convention.
703		n := 0
704		for n < len(pp.Path) && pp.Path[n] != 0 {
705			n++
706		}
707		bytes := (*[10000]byte)(unsafe.Pointer(&pp.Path[0]))[0:n]
708		sa.Name = string(bytes)
709		return sa, nil
710
711	case AF_INET:
712		pp := (*RawSockaddrInet4)(unsafe.Pointer(rsa))
713		sa := new(SockaddrInet4)
714		p := (*[2]byte)(unsafe.Pointer(&pp.Port))
715		sa.Port = int(p[0])<<8 + int(p[1])
716		for i := 0; i < len(sa.Addr); i++ {
717			sa.Addr[i] = pp.Addr[i]
718		}
719		return sa, nil
720
721	case AF_INET6:
722		pp := (*RawSockaddrInet6)(unsafe.Pointer(rsa))
723		sa := new(SockaddrInet6)
724		p := (*[2]byte)(unsafe.Pointer(&pp.Port))
725		sa.Port = int(p[0])<<8 + int(p[1])
726		sa.ZoneId = pp.Scope_id
727		for i := 0; i < len(sa.Addr); i++ {
728			sa.Addr[i] = pp.Addr[i]
729		}
730		return sa, nil
731
732	case AF_VSOCK:
733		pp := (*RawSockaddrVM)(unsafe.Pointer(rsa))
734		sa := &SockaddrVM{
735			CID:  pp.Cid,
736			Port: pp.Port,
737		}
738		return sa, nil
739	}
740	return nil, EAFNOSUPPORT
741}
742
743func Accept(fd int) (nfd int, sa Sockaddr, err error) {
744	var rsa RawSockaddrAny
745	var len _Socklen = SizeofSockaddrAny
746	nfd, err = accept(fd, &rsa, &len)
747	if err != nil {
748		return
749	}
750	sa, err = anyToSockaddr(&rsa)
751	if err != nil {
752		Close(nfd)
753		nfd = 0
754	}
755	return
756}
757
758func Accept4(fd int, flags int) (nfd int, sa Sockaddr, err error) {
759	var rsa RawSockaddrAny
760	var len _Socklen = SizeofSockaddrAny
761	nfd, err = accept4(fd, &rsa, &len, flags)
762	if err != nil {
763		return
764	}
765	if len > SizeofSockaddrAny {
766		panic("RawSockaddrAny too small")
767	}
768	sa, err = anyToSockaddr(&rsa)
769	if err != nil {
770		Close(nfd)
771		nfd = 0
772	}
773	return
774}
775
776func Getsockname(fd int) (sa Sockaddr, err error) {
777	var rsa RawSockaddrAny
778	var len _Socklen = SizeofSockaddrAny
779	if err = getsockname(fd, &rsa, &len); err != nil {
780		return
781	}
782	return anyToSockaddr(&rsa)
783}
784
785func GetsockoptIPMreqn(fd, level, opt int) (*IPMreqn, error) {
786	var value IPMreqn
787	vallen := _Socklen(SizeofIPMreqn)
788	err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
789	return &value, err
790}
791
792func GetsockoptUcred(fd, level, opt int) (*Ucred, error) {
793	var value Ucred
794	vallen := _Socklen(SizeofUcred)
795	err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
796	return &value, err
797}
798
799func GetsockoptTCPInfo(fd, level, opt int) (*TCPInfo, error) {
800	var value TCPInfo
801	vallen := _Socklen(SizeofTCPInfo)
802	err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
803	return &value, err
804}
805
806// GetsockoptString returns the string value of the socket option opt for the
807// socket associated with fd at the given socket level.
808func GetsockoptString(fd, level, opt int) (string, error) {
809	buf := make([]byte, 256)
810	vallen := _Socklen(len(buf))
811	err := getsockopt(fd, level, opt, unsafe.Pointer(&buf[0]), &vallen)
812	if err != nil {
813		if err == ERANGE {
814			buf = make([]byte, vallen)
815			err = getsockopt(fd, level, opt, unsafe.Pointer(&buf[0]), &vallen)
816		}
817		if err != nil {
818			return "", err
819		}
820	}
821	return string(buf[:vallen-1]), nil
822}
823
824func SetsockoptIPMreqn(fd, level, opt int, mreq *IPMreqn) (err error) {
825	return setsockopt(fd, level, opt, unsafe.Pointer(mreq), unsafe.Sizeof(*mreq))
826}
827
828// Keyctl Commands (http://man7.org/linux/man-pages/man2/keyctl.2.html)
829
830// KeyctlInt calls keyctl commands in which each argument is an int.
831// These commands are KEYCTL_REVOKE, KEYCTL_CHOWN, KEYCTL_CLEAR, KEYCTL_LINK,
832// KEYCTL_UNLINK, KEYCTL_NEGATE, KEYCTL_SET_REQKEY_KEYRING, KEYCTL_SET_TIMEOUT,
833// KEYCTL_ASSUME_AUTHORITY, KEYCTL_SESSION_TO_PARENT, KEYCTL_REJECT,
834// KEYCTL_INVALIDATE, and KEYCTL_GET_PERSISTENT.
835//sys	KeyctlInt(cmd int, arg2 int, arg3 int, arg4 int, arg5 int) (ret int, err error) = SYS_KEYCTL
836
837// KeyctlBuffer calls keyctl commands in which the third and fourth
838// arguments are a buffer and its length, respectively.
839// These commands are KEYCTL_UPDATE, KEYCTL_READ, and KEYCTL_INSTANTIATE.
840//sys	KeyctlBuffer(cmd int, arg2 int, buf []byte, arg5 int) (ret int, err error) = SYS_KEYCTL
841
842// KeyctlString calls keyctl commands which return a string.
843// These commands are KEYCTL_DESCRIBE and KEYCTL_GET_SECURITY.
844func KeyctlString(cmd int, id int) (string, error) {
845	// We must loop as the string data may change in between the syscalls.
846	// We could allocate a large buffer here to reduce the chance that the
847	// syscall needs to be called twice; however, this is unnecessary as
848	// the performance loss is negligible.
849	var buffer []byte
850	for {
851		// Try to fill the buffer with data
852		length, err := KeyctlBuffer(cmd, id, buffer, 0)
853		if err != nil {
854			return "", err
855		}
856
857		// Check if the data was written
858		if length <= len(buffer) {
859			// Exclude the null terminator
860			return string(buffer[:length-1]), nil
861		}
862
863		// Make a bigger buffer if needed
864		buffer = make([]byte, length)
865	}
866}
867
868// Keyctl commands with special signatures.
869
870// KeyctlGetKeyringID implements the KEYCTL_GET_KEYRING_ID command.
871// See the full documentation at:
872// http://man7.org/linux/man-pages/man3/keyctl_get_keyring_ID.3.html
873func KeyctlGetKeyringID(id int, create bool) (ringid int, err error) {
874	createInt := 0
875	if create {
876		createInt = 1
877	}
878	return KeyctlInt(KEYCTL_GET_KEYRING_ID, id, createInt, 0, 0)
879}
880
881// KeyctlSetperm implements the KEYCTL_SETPERM command. The perm value is the
882// key handle permission mask as described in the "keyctl setperm" section of
883// http://man7.org/linux/man-pages/man1/keyctl.1.html.
884// See the full documentation at:
885// http://man7.org/linux/man-pages/man3/keyctl_setperm.3.html
886func KeyctlSetperm(id int, perm uint32) error {
887	_, err := KeyctlInt(KEYCTL_SETPERM, id, int(perm), 0, 0)
888	return err
889}
890
891//sys	keyctlJoin(cmd int, arg2 string) (ret int, err error) = SYS_KEYCTL
892
893// KeyctlJoinSessionKeyring implements the KEYCTL_JOIN_SESSION_KEYRING command.
894// See the full documentation at:
895// http://man7.org/linux/man-pages/man3/keyctl_join_session_keyring.3.html
896func KeyctlJoinSessionKeyring(name string) (ringid int, err error) {
897	return keyctlJoin(KEYCTL_JOIN_SESSION_KEYRING, name)
898}
899
900//sys	keyctlSearch(cmd int, arg2 int, arg3 string, arg4 string, arg5 int) (ret int, err error) = SYS_KEYCTL
901
902// KeyctlSearch implements the KEYCTL_SEARCH command.
903// See the full documentation at:
904// http://man7.org/linux/man-pages/man3/keyctl_search.3.html
905func KeyctlSearch(ringid int, keyType, description string, destRingid int) (id int, err error) {
906	return keyctlSearch(KEYCTL_SEARCH, ringid, keyType, description, destRingid)
907}
908
909//sys	keyctlIOV(cmd int, arg2 int, payload []Iovec, arg5 int) (err error) = SYS_KEYCTL
910
911// KeyctlInstantiateIOV implements the KEYCTL_INSTANTIATE_IOV command. This
912// command is similar to KEYCTL_INSTANTIATE, except that the payload is a slice
913// of Iovec (each of which represents a buffer) instead of a single buffer.
914// See the full documentation at:
915// http://man7.org/linux/man-pages/man3/keyctl_instantiate_iov.3.html
916func KeyctlInstantiateIOV(id int, payload []Iovec, ringid int) error {
917	return keyctlIOV(KEYCTL_INSTANTIATE_IOV, id, payload, ringid)
918}
919
920//sys	keyctlDH(cmd int, arg2 *KeyctlDHParams, buf []byte) (ret int, err error) = SYS_KEYCTL
921
922// KeyctlDHCompute implements the KEYCTL_DH_COMPUTE command. This command
923// computes a Diffie-Hellman shared secret based on the provide params. The
924// secret is written to the provided buffer and the returned size is the number
925// of bytes written (returning an error if there is insufficient space in the
926// buffer). If a nil buffer is passed in, this function returns the minimum
927// buffer length needed to store the appropriate data. Note that this differs
928// from KEYCTL_READ's behavior which always returns the requested payload size.
929// See the full documentation at:
930// http://man7.org/linux/man-pages/man3/keyctl_dh_compute.3.html
931func KeyctlDHCompute(params *KeyctlDHParams, buffer []byte) (size int, err error) {
932	return keyctlDH(KEYCTL_DH_COMPUTE, params, buffer)
933}
934
935func Recvmsg(fd int, p, oob []byte, flags int) (n, oobn int, recvflags int, from Sockaddr, err error) {
936	var msg Msghdr
937	var rsa RawSockaddrAny
938	msg.Name = (*byte)(unsafe.Pointer(&rsa))
939	msg.Namelen = uint32(SizeofSockaddrAny)
940	var iov Iovec
941	if len(p) > 0 {
942		iov.Base = &p[0]
943		iov.SetLen(len(p))
944	}
945	var dummy byte
946	if len(oob) > 0 {
947		if len(p) == 0 {
948			var sockType int
949			sockType, err = GetsockoptInt(fd, SOL_SOCKET, SO_TYPE)
950			if err != nil {
951				return
952			}
953			// receive at least one normal byte
954			if sockType != SOCK_DGRAM {
955				iov.Base = &dummy
956				iov.SetLen(1)
957			}
958		}
959		msg.Control = &oob[0]
960		msg.SetControllen(len(oob))
961	}
962	msg.Iov = &iov
963	msg.Iovlen = 1
964	if n, err = recvmsg(fd, &msg, flags); err != nil {
965		return
966	}
967	oobn = int(msg.Controllen)
968	recvflags = int(msg.Flags)
969	// source address is only specified if the socket is unconnected
970	if rsa.Addr.Family != AF_UNSPEC {
971		from, err = anyToSockaddr(&rsa)
972	}
973	return
974}
975
976func Sendmsg(fd int, p, oob []byte, to Sockaddr, flags int) (err error) {
977	_, err = SendmsgN(fd, p, oob, to, flags)
978	return
979}
980
981func SendmsgN(fd int, p, oob []byte, to Sockaddr, flags int) (n int, err error) {
982	var ptr unsafe.Pointer
983	var salen _Socklen
984	if to != nil {
985		var err error
986		ptr, salen, err = to.sockaddr()
987		if err != nil {
988			return 0, err
989		}
990	}
991	var msg Msghdr
992	msg.Name = (*byte)(ptr)
993	msg.Namelen = uint32(salen)
994	var iov Iovec
995	if len(p) > 0 {
996		iov.Base = &p[0]
997		iov.SetLen(len(p))
998	}
999	var dummy byte
1000	if len(oob) > 0 {
1001		if len(p) == 0 {
1002			var sockType int
1003			sockType, err = GetsockoptInt(fd, SOL_SOCKET, SO_TYPE)
1004			if err != nil {
1005				return 0, err
1006			}
1007			// send at least one normal byte
1008			if sockType != SOCK_DGRAM {
1009				iov.Base = &dummy
1010				iov.SetLen(1)
1011			}
1012		}
1013		msg.Control = &oob[0]
1014		msg.SetControllen(len(oob))
1015	}
1016	msg.Iov = &iov
1017	msg.Iovlen = 1
1018	if n, err = sendmsg(fd, &msg, flags); err != nil {
1019		return 0, err
1020	}
1021	if len(oob) > 0 && len(p) == 0 {
1022		n = 0
1023	}
1024	return n, nil
1025}
1026
1027// BindToDevice binds the socket associated with fd to device.
1028func BindToDevice(fd int, device string) (err error) {
1029	return SetsockoptString(fd, SOL_SOCKET, SO_BINDTODEVICE, device)
1030}
1031
1032//sys	ptrace(request int, pid int, addr uintptr, data uintptr) (err error)
1033
1034func ptracePeek(req int, pid int, addr uintptr, out []byte) (count int, err error) {
1035	// The peek requests are machine-size oriented, so we wrap it
1036	// to retrieve arbitrary-length data.
1037
1038	// The ptrace syscall differs from glibc's ptrace.
1039	// Peeks returns the word in *data, not as the return value.
1040
1041	var buf [sizeofPtr]byte
1042
1043	// Leading edge. PEEKTEXT/PEEKDATA don't require aligned
1044	// access (PEEKUSER warns that it might), but if we don't
1045	// align our reads, we might straddle an unmapped page
1046	// boundary and not get the bytes leading up to the page
1047	// boundary.
1048	n := 0
1049	if addr%sizeofPtr != 0 {
1050		err = ptrace(req, pid, addr-addr%sizeofPtr, uintptr(unsafe.Pointer(&buf[0])))
1051		if err != nil {
1052			return 0, err
1053		}
1054		n += copy(out, buf[addr%sizeofPtr:])
1055		out = out[n:]
1056	}
1057
1058	// Remainder.
1059	for len(out) > 0 {
1060		// We use an internal buffer to guarantee alignment.
1061		// It's not documented if this is necessary, but we're paranoid.
1062		err = ptrace(req, pid, addr+uintptr(n), uintptr(unsafe.Pointer(&buf[0])))
1063		if err != nil {
1064			return n, err
1065		}
1066		copied := copy(out, buf[0:])
1067		n += copied
1068		out = out[copied:]
1069	}
1070
1071	return n, nil
1072}
1073
1074func PtracePeekText(pid int, addr uintptr, out []byte) (count int, err error) {
1075	return ptracePeek(PTRACE_PEEKTEXT, pid, addr, out)
1076}
1077
1078func PtracePeekData(pid int, addr uintptr, out []byte) (count int, err error) {
1079	return ptracePeek(PTRACE_PEEKDATA, pid, addr, out)
1080}
1081
1082func PtracePeekUser(pid int, addr uintptr, out []byte) (count int, err error) {
1083	return ptracePeek(PTRACE_PEEKUSR, pid, addr, out)
1084}
1085
1086func ptracePoke(pokeReq int, peekReq int, pid int, addr uintptr, data []byte) (count int, err error) {
1087	// As for ptracePeek, we need to align our accesses to deal
1088	// with the possibility of straddling an invalid page.
1089
1090	// Leading edge.
1091	n := 0
1092	if addr%sizeofPtr != 0 {
1093		var buf [sizeofPtr]byte
1094		err = ptrace(peekReq, pid, addr-addr%sizeofPtr, uintptr(unsafe.Pointer(&buf[0])))
1095		if err != nil {
1096			return 0, err
1097		}
1098		n += copy(buf[addr%sizeofPtr:], data)
1099		word := *((*uintptr)(unsafe.Pointer(&buf[0])))
1100		err = ptrace(pokeReq, pid, addr-addr%sizeofPtr, word)
1101		if err != nil {
1102			return 0, err
1103		}
1104		data = data[n:]
1105	}
1106
1107	// Interior.
1108	for len(data) > sizeofPtr {
1109		word := *((*uintptr)(unsafe.Pointer(&data[0])))
1110		err = ptrace(pokeReq, pid, addr+uintptr(n), word)
1111		if err != nil {
1112			return n, err
1113		}
1114		n += sizeofPtr
1115		data = data[sizeofPtr:]
1116	}
1117
1118	// Trailing edge.
1119	if len(data) > 0 {
1120		var buf [sizeofPtr]byte
1121		err = ptrace(peekReq, pid, addr+uintptr(n), uintptr(unsafe.Pointer(&buf[0])))
1122		if err != nil {
1123			return n, err
1124		}
1125		copy(buf[0:], data)
1126		word := *((*uintptr)(unsafe.Pointer(&buf[0])))
1127		err = ptrace(pokeReq, pid, addr+uintptr(n), word)
1128		if err != nil {
1129			return n, err
1130		}
1131		n += len(data)
1132	}
1133
1134	return n, nil
1135}
1136
1137func PtracePokeText(pid int, addr uintptr, data []byte) (count int, err error) {
1138	return ptracePoke(PTRACE_POKETEXT, PTRACE_PEEKTEXT, pid, addr, data)
1139}
1140
1141func PtracePokeData(pid int, addr uintptr, data []byte) (count int, err error) {
1142	return ptracePoke(PTRACE_POKEDATA, PTRACE_PEEKDATA, pid, addr, data)
1143}
1144
1145func PtracePokeUser(pid int, addr uintptr, data []byte) (count int, err error) {
1146	return ptracePoke(PTRACE_POKEUSR, PTRACE_PEEKUSR, pid, addr, data)
1147}
1148
1149func PtraceGetRegs(pid int, regsout *PtraceRegs) (err error) {
1150	return ptrace(PTRACE_GETREGS, pid, 0, uintptr(unsafe.Pointer(regsout)))
1151}
1152
1153func PtraceSetRegs(pid int, regs *PtraceRegs) (err error) {
1154	return ptrace(PTRACE_SETREGS, pid, 0, uintptr(unsafe.Pointer(regs)))
1155}
1156
1157func PtraceSetOptions(pid int, options int) (err error) {
1158	return ptrace(PTRACE_SETOPTIONS, pid, 0, uintptr(options))
1159}
1160
1161func PtraceGetEventMsg(pid int) (msg uint, err error) {
1162	var data _C_long
1163	err = ptrace(PTRACE_GETEVENTMSG, pid, 0, uintptr(unsafe.Pointer(&data)))
1164	msg = uint(data)
1165	return
1166}
1167
1168func PtraceCont(pid int, signal int) (err error) {
1169	return ptrace(PTRACE_CONT, pid, 0, uintptr(signal))
1170}
1171
1172func PtraceSyscall(pid int, signal int) (err error) {
1173	return ptrace(PTRACE_SYSCALL, pid, 0, uintptr(signal))
1174}
1175
1176func PtraceSingleStep(pid int) (err error) { return ptrace(PTRACE_SINGLESTEP, pid, 0, 0) }
1177
1178func PtraceAttach(pid int) (err error) { return ptrace(PTRACE_ATTACH, pid, 0, 0) }
1179
1180func PtraceDetach(pid int) (err error) { return ptrace(PTRACE_DETACH, pid, 0, 0) }
1181
1182//sys	reboot(magic1 uint, magic2 uint, cmd int, arg string) (err error)
1183
1184func Reboot(cmd int) (err error) {
1185	return reboot(LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2, cmd, "")
1186}
1187
1188func ReadDirent(fd int, buf []byte) (n int, err error) {
1189	return Getdents(fd, buf)
1190}
1191
1192//sys	mount(source string, target string, fstype string, flags uintptr, data *byte) (err error)
1193
1194func Mount(source string, target string, fstype string, flags uintptr, data string) (err error) {
1195	// Certain file systems get rather angry and EINVAL if you give
1196	// them an empty string of data, rather than NULL.
1197	if data == "" {
1198		return mount(source, target, fstype, flags, nil)
1199	}
1200	datap, err := BytePtrFromString(data)
1201	if err != nil {
1202		return err
1203	}
1204	return mount(source, target, fstype, flags, datap)
1205}
1206
1207// Sendto
1208// Recvfrom
1209// Socketpair
1210
1211/*
1212 * Direct access
1213 */
1214//sys	Acct(path string) (err error)
1215//sys	AddKey(keyType string, description string, payload []byte, ringid int) (id int, err error)
1216//sys	Adjtimex(buf *Timex) (state int, err error)
1217//sys	Chdir(path string) (err error)
1218//sys	Chroot(path string) (err error)
1219//sys	ClockGettime(clockid int32, time *Timespec) (err error)
1220//sys	Close(fd int) (err error)
1221//sys	CopyFileRange(rfd int, roff *int64, wfd int, woff *int64, len int, flags int) (n int, err error)
1222//sys	Dup(oldfd int) (fd int, err error)
1223//sys	Dup3(oldfd int, newfd int, flags int) (err error)
1224//sysnb	EpollCreate(size int) (fd int, err error)
1225//sysnb	EpollCreate1(flag int) (fd int, err error)
1226//sysnb	EpollCtl(epfd int, op int, fd int, event *EpollEvent) (err error)
1227//sys	Eventfd(initval uint, flags int) (fd int, err error) = SYS_EVENTFD2
1228//sys	Exit(code int) = SYS_EXIT_GROUP
1229//sys	Faccessat(dirfd int, path string, mode uint32, flags int) (err error)
1230//sys	Fallocate(fd int, mode uint32, off int64, len int64) (err error)
1231//sys	Fchdir(fd int) (err error)
1232//sys	Fchmod(fd int, mode uint32) (err error)
1233//sys	Fchownat(dirfd int, path string, uid int, gid int, flags int) (err error)
1234//sys	fcntl(fd int, cmd int, arg int) (val int, err error)
1235//sys	Fdatasync(fd int) (err error)
1236//sys	Flock(fd int, how int) (err error)
1237//sys	Fsync(fd int) (err error)
1238//sys	Getdents(fd int, buf []byte) (n int, err error) = SYS_GETDENTS64
1239//sysnb	Getpgid(pid int) (pgid int, err error)
1240
1241func Getpgrp() (pid int) {
1242	pid, _ = Getpgid(0)
1243	return
1244}
1245
1246//sysnb	Getpid() (pid int)
1247//sysnb	Getppid() (ppid int)
1248//sys	Getpriority(which int, who int) (prio int, err error)
1249//sys	Getrandom(buf []byte, flags int) (n int, err error)
1250//sysnb	Getrusage(who int, rusage *Rusage) (err error)
1251//sysnb	Getsid(pid int) (sid int, err error)
1252//sysnb	Gettid() (tid int)
1253//sys	Getxattr(path string, attr string, dest []byte) (sz int, err error)
1254//sys	InotifyAddWatch(fd int, pathname string, mask uint32) (watchdesc int, err error)
1255//sysnb	InotifyInit1(flags int) (fd int, err error)
1256//sysnb	InotifyRmWatch(fd int, watchdesc uint32) (success int, err error)
1257//sysnb	Kill(pid int, sig syscall.Signal) (err error)
1258//sys	Klogctl(typ int, buf []byte) (n int, err error) = SYS_SYSLOG
1259//sys	Lgetxattr(path string, attr string, dest []byte) (sz int, err error)
1260//sys	Listxattr(path string, dest []byte) (sz int, err error)
1261//sys	Llistxattr(path string, dest []byte) (sz int, err error)
1262//sys	Lremovexattr(path string, attr string) (err error)
1263//sys	Lsetxattr(path string, attr string, data []byte, flags int) (err error)
1264//sys	Mkdirat(dirfd int, path string, mode uint32) (err error)
1265//sys	Mknodat(dirfd int, path string, mode uint32, dev int) (err error)
1266//sys	Nanosleep(time *Timespec, leftover *Timespec) (err error)
1267//sys	PerfEventOpen(attr *PerfEventAttr, pid int, cpu int, groupFd int, flags int) (fd int, err error)
1268//sys	PivotRoot(newroot string, putold string) (err error) = SYS_PIVOT_ROOT
1269//sysnb prlimit(pid int, resource int, newlimit *Rlimit, old *Rlimit) (err error) = SYS_PRLIMIT64
1270//sys   Prctl(option int, arg2 uintptr, arg3 uintptr, arg4 uintptr, arg5 uintptr) (err error)
1271//sys	Pselect(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timespec, sigmask *Sigset_t) (n int, err error) = SYS_PSELECT6
1272//sys	read(fd int, p []byte) (n int, err error)
1273//sys	Removexattr(path string, attr string) (err error)
1274//sys	Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error)
1275//sys	RequestKey(keyType string, description string, callback string, destRingid int) (id int, err error)
1276//sys	Setdomainname(p []byte) (err error)
1277//sys	Sethostname(p []byte) (err error)
1278//sysnb	Setpgid(pid int, pgid int) (err error)
1279//sysnb	Setsid() (pid int, err error)
1280//sysnb	Settimeofday(tv *Timeval) (err error)
1281//sys	Setns(fd int, nstype int) (err error)
1282
1283// issue 1435.
1284// On linux Setuid and Setgid only affects the current thread, not the process.
1285// This does not match what most callers expect so we must return an error
1286// here rather than letting the caller think that the call succeeded.
1287
1288func Setuid(uid int) (err error) {
1289	return EOPNOTSUPP
1290}
1291
1292func Setgid(uid int) (err error) {
1293	return EOPNOTSUPP
1294}
1295
1296//sys	Setpriority(which int, who int, prio int) (err error)
1297//sys	Setxattr(path string, attr string, data []byte, flags int) (err error)
1298//sys	Statx(dirfd int, path string, flags int, mask int, stat *Statx_t) (err error)
1299//sys	Sync()
1300//sys	Syncfs(fd int) (err error)
1301//sysnb	Sysinfo(info *Sysinfo_t) (err error)
1302//sys	Tee(rfd int, wfd int, len int, flags int) (n int64, err error)
1303//sysnb	Tgkill(tgid int, tid int, sig syscall.Signal) (err error)
1304//sysnb	Times(tms *Tms) (ticks uintptr, err error)
1305//sysnb	Umask(mask int) (oldmask int)
1306//sysnb	Uname(buf *Utsname) (err error)
1307//sys	Unmount(target string, flags int) (err error) = SYS_UMOUNT2
1308//sys	Unshare(flags int) (err error)
1309//sys	Ustat(dev int, ubuf *Ustat_t) (err error)
1310//sys	write(fd int, p []byte) (n int, err error)
1311//sys	exitThread(code int) (err error) = SYS_EXIT
1312//sys	readlen(fd int, p *byte, np int) (n int, err error) = SYS_READ
1313//sys	writelen(fd int, p *byte, np int) (n int, err error) = SYS_WRITE
1314
1315// mmap varies by architecture; see syscall_linux_*.go.
1316//sys	munmap(addr uintptr, length uintptr) (err error)
1317
1318var mapper = &mmapper{
1319	active: make(map[*byte][]byte),
1320	mmap:   mmap,
1321	munmap: munmap,
1322}
1323
1324func Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
1325	return mapper.Mmap(fd, offset, length, prot, flags)
1326}
1327
1328func Munmap(b []byte) (err error) {
1329	return mapper.Munmap(b)
1330}
1331
1332//sys	Madvise(b []byte, advice int) (err error)
1333//sys	Mprotect(b []byte, prot int) (err error)
1334//sys	Mlock(b []byte) (err error)
1335//sys	Mlockall(flags int) (err error)
1336//sys	Msync(b []byte, flags int) (err error)
1337//sys	Munlock(b []byte) (err error)
1338//sys	Munlockall() (err error)
1339
1340// Vmsplice splices user pages from a slice of Iovecs into a pipe specified by fd,
1341// using the specified flags.
1342func Vmsplice(fd int, iovs []Iovec, flags int) (int, error) {
1343	n, _, errno := Syscall6(
1344		SYS_VMSPLICE,
1345		uintptr(fd),
1346		uintptr(unsafe.Pointer(&iovs[0])),
1347		uintptr(len(iovs)),
1348		uintptr(flags),
1349		0,
1350		0,
1351	)
1352	if errno != 0 {
1353		return 0, syscall.Errno(errno)
1354	}
1355
1356	return int(n), nil
1357}
1358
1359/*
1360 * Unimplemented
1361 */
1362// AfsSyscall
1363// Alarm
1364// ArchPrctl
1365// Brk
1366// Capget
1367// Capset
1368// ClockGetres
1369// ClockNanosleep
1370// ClockSettime
1371// Clone
1372// CreateModule
1373// DeleteModule
1374// EpollCtlOld
1375// EpollPwait
1376// EpollWaitOld
1377// Execve
1378// Fgetxattr
1379// Flistxattr
1380// Fork
1381// Fremovexattr
1382// Fsetxattr
1383// Futex
1384// GetKernelSyms
1385// GetMempolicy
1386// GetRobustList
1387// GetThreadArea
1388// Getitimer
1389// Getpmsg
1390// IoCancel
1391// IoDestroy
1392// IoGetevents
1393// IoSetup
1394// IoSubmit
1395// IoprioGet
1396// IoprioSet
1397// KexecLoad
1398// LookupDcookie
1399// Mbind
1400// MigratePages
1401// Mincore
1402// ModifyLdt
1403// Mount
1404// MovePages
1405// MqGetsetattr
1406// MqNotify
1407// MqOpen
1408// MqTimedreceive
1409// MqTimedsend
1410// MqUnlink
1411// Mremap
1412// Msgctl
1413// Msgget
1414// Msgrcv
1415// Msgsnd
1416// Nfsservctl
1417// Personality
1418// Pselect6
1419// Ptrace
1420// Putpmsg
1421// QueryModule
1422// Quotactl
1423// Readahead
1424// Readv
1425// RemapFilePages
1426// RestartSyscall
1427// RtSigaction
1428// RtSigpending
1429// RtSigprocmask
1430// RtSigqueueinfo
1431// RtSigreturn
1432// RtSigsuspend
1433// RtSigtimedwait
1434// SchedGetPriorityMax
1435// SchedGetPriorityMin
1436// SchedGetparam
1437// SchedGetscheduler
1438// SchedRrGetInterval
1439// SchedSetparam
1440// SchedYield
1441// Security
1442// Semctl
1443// Semget
1444// Semop
1445// Semtimedop
1446// SetMempolicy
1447// SetRobustList
1448// SetThreadArea
1449// SetTidAddress
1450// Shmat
1451// Shmctl
1452// Shmdt
1453// Shmget
1454// Sigaltstack
1455// Signalfd
1456// Swapoff
1457// Swapon
1458// Sysfs
1459// TimerCreate
1460// TimerDelete
1461// TimerGetoverrun
1462// TimerGettime
1463// TimerSettime
1464// Timerfd
1465// Tkill (obsolete)
1466// Tuxcall
1467// Umount2
1468// Uselib
1469// Utimensat
1470// Vfork
1471// Vhangup
1472// Vserver
1473// Waitid
1474// _Sysctl
1475