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//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris
6// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
7
8package unix
9
10import (
11 "bytes"
12 "sort"
13 "sync"
14 "syscall"
15 "unsafe"
16)
17
18var (
19 Stdin = 0
20 Stdout = 1
21 Stderr = 2
22)
23
24// Do the interface allocations only once for common
25// Errno values.
26var (
27 errEAGAIN error = syscall.EAGAIN
28 errEINVAL error = syscall.EINVAL
29 errENOENT error = syscall.ENOENT
30)
31
32var (
33 signalNameMapOnce sync.Once
34 signalNameMap map[string]syscall.Signal
35)
36
37// errnoErr returns common boxed Errno values, to prevent
38// allocations at runtime.
39func errnoErr(e syscall.Errno) error {
40 switch e {
41 case 0:
42 return nil
43 case EAGAIN:
44 return errEAGAIN
45 case EINVAL:
46 return errEINVAL
47 case ENOENT:
48 return errENOENT
49 }
50 return e
51}
52
53// ErrnoName returns the error name for error number e.
54func ErrnoName(e syscall.Errno) string {
55 i := sort.Search(len(errorList), func(i int) bool {
56 return errorList[i].num >= e
57 })
58 if i < len(errorList) && errorList[i].num == e {
59 return errorList[i].name
60 }
61 return ""
62}
63
64// SignalName returns the signal name for signal number s.
65func SignalName(s syscall.Signal) string {
66 i := sort.Search(len(signalList), func(i int) bool {
67 return signalList[i].num >= s
68 })
69 if i < len(signalList) && signalList[i].num == s {
70 return signalList[i].name
71 }
72 return ""
73}
74
75// SignalNum returns the syscall.Signal for signal named s,
76// or 0 if a signal with such name is not found.
77// The signal name should start with "SIG".
78func SignalNum(s string) syscall.Signal {
79 signalNameMapOnce.Do(func() {
80 signalNameMap = make(map[string]syscall.Signal, len(signalList))
81 for _, signal := range signalList {
82 signalNameMap[signal.name] = signal.num
83 }
84 })
85 return signalNameMap[s]
86}
87
88// clen returns the index of the first NULL byte in n or len(n) if n contains no NULL byte.
89func clen(n []byte) int {
90 i := bytes.IndexByte(n, 0)
91 if i == -1 {
92 i = len(n)
93 }
94 return i
95}
96
97// Mmap manager, for use by operating system-specific implementations.
98
99type mmapper struct {
100 sync.Mutex
101 active map[*byte][]byte // active mappings; key is last byte in mapping
102 mmap func(addr, length uintptr, prot, flags, fd int, offset int64) (uintptr, error)
103 munmap func(addr uintptr, length uintptr) error
104}
105
106func (m *mmapper) Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
107 if length <= 0 {
108 return nil, EINVAL
109 }
110
111 // Map the requested memory.
112 addr, errno := m.mmap(0, uintptr(length), prot, flags, fd, offset)
113 if errno != nil {
114 return nil, errno
115 }
116
117 // Use unsafe to convert addr into a []byte.
118 b := unsafe.Slice((*byte)(unsafe.Pointer(addr)), length)
119
120 // Register mapping in m and return it.
121 p := &b[cap(b)-1]
122 m.Lock()
123 defer m.Unlock()
124 m.active[p] = b
125 return b, nil
126}
127
128func (m *mmapper) Munmap(data []byte) (err error) {
129 if len(data) == 0 || len(data) != cap(data) {
130 return EINVAL
131 }
132
133 // Find the base of the mapping.
134 p := &data[cap(data)-1]
135 m.Lock()
136 defer m.Unlock()
137 b := m.active[p]
138 if b == nil || &b[0] != &data[0] {
139 return EINVAL
140 }
141
142 // Unmap the memory and update m.
143 if errno := m.munmap(uintptr(unsafe.Pointer(&b[0])), uintptr(len(b))); errno != nil {
144 return errno
145 }
146 delete(m.active, p)
147 return nil
148}
149
150func Read(fd int, p []byte) (n int, err error) {
151 n, err = read(fd, p)
152 if raceenabled {
153 if n > 0 {
154 raceWriteRange(unsafe.Pointer(&p[0]), n)
155 }
156 if err == nil {
157 raceAcquire(unsafe.Pointer(&ioSync))
158 }
159 }
160 return
161}
162
163func Write(fd int, p []byte) (n int, err error) {
164 if raceenabled {
165 raceReleaseMerge(unsafe.Pointer(&ioSync))
166 }
167 n, err = write(fd, p)
168 if raceenabled && n > 0 {
169 raceReadRange(unsafe.Pointer(&p[0]), n)
170 }
171 return
172}
173
174func Pread(fd int, p []byte, offset int64) (n int, err error) {
175 n, err = pread(fd, p, offset)
176 if raceenabled {
177 if n > 0 {
178 raceWriteRange(unsafe.Pointer(&p[0]), n)
179 }
180 if err == nil {
181 raceAcquire(unsafe.Pointer(&ioSync))
182 }
183 }
184 return
185}
186
187func Pwrite(fd int, p []byte, offset int64) (n int, err error) {
188 if raceenabled {
189 raceReleaseMerge(unsafe.Pointer(&ioSync))
190 }
191 n, err = pwrite(fd, p, offset)
192 if raceenabled && n > 0 {
193 raceReadRange(unsafe.Pointer(&p[0]), n)
194 }
195 return
196}
197
198// For testing: clients can set this flag to force
199// creation of IPv6 sockets to return EAFNOSUPPORT.
200var SocketDisableIPv6 bool
201
202// Sockaddr represents a socket address.
203type Sockaddr interface {
204 sockaddr() (ptr unsafe.Pointer, len _Socklen, err error) // lowercase; only we can define Sockaddrs
205}
206
207// SockaddrInet4 implements the Sockaddr interface for AF_INET type sockets.
208type SockaddrInet4 struct {
209 Port int
210 Addr [4]byte
211 raw RawSockaddrInet4
212}
213
214// SockaddrInet6 implements the Sockaddr interface for AF_INET6 type sockets.
215type SockaddrInet6 struct {
216 Port int
217 ZoneId uint32
218 Addr [16]byte
219 raw RawSockaddrInet6
220}
221
222// SockaddrUnix implements the Sockaddr interface for AF_UNIX type sockets.
223type SockaddrUnix struct {
224 Name string
225 raw RawSockaddrUnix
226}
227
228func Bind(fd int, sa Sockaddr) (err error) {
229 ptr, n, err := sa.sockaddr()
230 if err != nil {
231 return err
232 }
233 return bind(fd, ptr, n)
234}
235
236func Connect(fd int, sa Sockaddr) (err error) {
237 ptr, n, err := sa.sockaddr()
238 if err != nil {
239 return err
240 }
241 return connect(fd, ptr, n)
242}
243
244func Getpeername(fd int) (sa Sockaddr, err error) {
245 var rsa RawSockaddrAny
246 var len _Socklen = SizeofSockaddrAny
247 if err = getpeername(fd, &rsa, &len); err != nil {
248 return
249 }
250 return anyToSockaddr(fd, &rsa)
251}
252
253func GetsockoptByte(fd, level, opt int) (value byte, err error) {
254 var n byte
255 vallen := _Socklen(1)
256 err = getsockopt(fd, level, opt, unsafe.Pointer(&n), &vallen)
257 return n, err
258}
259
260func GetsockoptInt(fd, level, opt int) (value int, err error) {
261 var n int32
262 vallen := _Socklen(4)
263 err = getsockopt(fd, level, opt, unsafe.Pointer(&n), &vallen)
264 return int(n), err
265}
266
267func GetsockoptInet4Addr(fd, level, opt int) (value [4]byte, err error) {
268 vallen := _Socklen(4)
269 err = getsockopt(fd, level, opt, unsafe.Pointer(&value[0]), &vallen)
270 return value, err
271}
272
273func GetsockoptIPMreq(fd, level, opt int) (*IPMreq, error) {
274 var value IPMreq
275 vallen := _Socklen(SizeofIPMreq)
276 err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
277 return &value, err
278}
279
280func GetsockoptIPv6Mreq(fd, level, opt int) (*IPv6Mreq, error) {
281 var value IPv6Mreq
282 vallen := _Socklen(SizeofIPv6Mreq)
283 err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
284 return &value, err
285}
286
287func GetsockoptIPv6MTUInfo(fd, level, opt int) (*IPv6MTUInfo, error) {
288 var value IPv6MTUInfo
289 vallen := _Socklen(SizeofIPv6MTUInfo)
290 err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
291 return &value, err
292}
293
294func GetsockoptICMPv6Filter(fd, level, opt int) (*ICMPv6Filter, error) {
295 var value ICMPv6Filter
296 vallen := _Socklen(SizeofICMPv6Filter)
297 err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
298 return &value, err
299}
300
301func GetsockoptLinger(fd, level, opt int) (*Linger, error) {
302 var linger Linger
303 vallen := _Socklen(SizeofLinger)
304 err := getsockopt(fd, level, opt, unsafe.Pointer(&linger), &vallen)
305 return &linger, err
306}
307
308func GetsockoptTimeval(fd, level, opt int) (*Timeval, error) {
309 var tv Timeval
310 vallen := _Socklen(unsafe.Sizeof(tv))
311 err := getsockopt(fd, level, opt, unsafe.Pointer(&tv), &vallen)
312 return &tv, err
313}
314
315func GetsockoptUint64(fd, level, opt int) (value uint64, err error) {
316 var n uint64
317 vallen := _Socklen(8)
318 err = getsockopt(fd, level, opt, unsafe.Pointer(&n), &vallen)
319 return n, err
320}
321
322func Recvfrom(fd int, p []byte, flags int) (n int, from Sockaddr, err error) {
323 var rsa RawSockaddrAny
324 var len _Socklen = SizeofSockaddrAny
325 if n, err = recvfrom(fd, p, flags, &rsa, &len); err != nil {
326 return
327 }
328 if rsa.Addr.Family != AF_UNSPEC {
329 from, err = anyToSockaddr(fd, &rsa)
330 }
331 return
332}
333
334// Recvmsg receives a message from a socket using the recvmsg system call. The
335// received non-control data will be written to p, and any "out of band"
336// control data will be written to oob. The flags are passed to recvmsg.
337//
338// The results are:
339// - n is the number of non-control data bytes read into p
340// - oobn is the number of control data bytes read into oob; this may be interpreted using [ParseSocketControlMessage]
341// - recvflags is flags returned by recvmsg
342// - from is the address of the sender
343//
344// If the underlying socket type is not SOCK_DGRAM, a received message
345// containing oob data and a single '\0' of non-control data is treated as if
346// the message contained only control data, i.e. n will be zero on return.
347func Recvmsg(fd int, p, oob []byte, flags int) (n, oobn int, recvflags int, from Sockaddr, err error) {
348 var iov [1]Iovec
349 if len(p) > 0 {
350 iov[0].Base = &p[0]
351 iov[0].SetLen(len(p))
352 }
353 var rsa RawSockaddrAny
354 n, oobn, recvflags, err = recvmsgRaw(fd, iov[:], oob, flags, &rsa)
355 // source address is only specified if the socket is unconnected
356 if rsa.Addr.Family != AF_UNSPEC {
357 from, err = anyToSockaddr(fd, &rsa)
358 }
359 return
360}
361
362// RecvmsgBuffers receives a message from a socket using the recvmsg system
363// call. This function is equivalent to Recvmsg, but non-control data read is
364// scattered into the buffers slices.
365func RecvmsgBuffers(fd int, buffers [][]byte, oob []byte, flags int) (n, oobn int, recvflags int, from Sockaddr, err error) {
366 iov := make([]Iovec, len(buffers))
367 for i := range buffers {
368 if len(buffers[i]) > 0 {
369 iov[i].Base = &buffers[i][0]
370 iov[i].SetLen(len(buffers[i]))
371 } else {
372 iov[i].Base = (*byte)(unsafe.Pointer(&_zero))
373 }
374 }
375 var rsa RawSockaddrAny
376 n, oobn, recvflags, err = recvmsgRaw(fd, iov, oob, flags, &rsa)
377 if err == nil && rsa.Addr.Family != AF_UNSPEC {
378 from, err = anyToSockaddr(fd, &rsa)
379 }
380 return
381}
382
383// Sendmsg sends a message on a socket to an address using the sendmsg system
384// call. This function is equivalent to SendmsgN, but does not return the
385// number of bytes actually sent.
386func Sendmsg(fd int, p, oob []byte, to Sockaddr, flags int) (err error) {
387 _, err = SendmsgN(fd, p, oob, to, flags)
388 return
389}
390
391// SendmsgN sends a message on a socket to an address using the sendmsg system
392// call. p contains the non-control data to send, and oob contains the "out of
393// band" control data. The flags are passed to sendmsg. The number of
394// non-control bytes actually written to the socket is returned.
395//
396// Some socket types do not support sending control data without accompanying
397// non-control data. If p is empty, and oob contains control data, and the
398// underlying socket type is not SOCK_DGRAM, p will be treated as containing a
399// single '\0' and the return value will indicate zero bytes sent.
400//
401// The Go function Recvmsg, if called with an empty p and a non-empty oob,
402// will read and ignore this additional '\0'. If the message is received by
403// code that does not use Recvmsg, or that does not use Go at all, that code
404// will need to be written to expect and ignore the additional '\0'.
405//
406// If you need to send non-empty oob with p actually empty, and if the
407// underlying socket type supports it, you can do so via a raw system call as
408// follows:
409//
410// msg := &unix.Msghdr{
411// Control: &oob[0],
412// }
413// msg.SetControllen(len(oob))
414// n, _, errno := unix.Syscall(unix.SYS_SENDMSG, uintptr(fd), uintptr(unsafe.Pointer(msg)), flags)
415func SendmsgN(fd int, p, oob []byte, to Sockaddr, flags int) (n int, err error) {
416 var iov [1]Iovec
417 if len(p) > 0 {
418 iov[0].Base = &p[0]
419 iov[0].SetLen(len(p))
420 }
421 var ptr unsafe.Pointer
422 var salen _Socklen
423 if to != nil {
424 ptr, salen, err = to.sockaddr()
425 if err != nil {
426 return 0, err
427 }
428 }
429 return sendmsgN(fd, iov[:], oob, ptr, salen, flags)
430}
431
432// SendmsgBuffers sends a message on a socket to an address using the sendmsg
433// system call. This function is equivalent to SendmsgN, but the non-control
434// data is gathered from buffers.
435func SendmsgBuffers(fd int, buffers [][]byte, oob []byte, to Sockaddr, flags int) (n int, err error) {
436 iov := make([]Iovec, len(buffers))
437 for i := range buffers {
438 if len(buffers[i]) > 0 {
439 iov[i].Base = &buffers[i][0]
440 iov[i].SetLen(len(buffers[i]))
441 } else {
442 iov[i].Base = (*byte)(unsafe.Pointer(&_zero))
443 }
444 }
445 var ptr unsafe.Pointer
446 var salen _Socklen
447 if to != nil {
448 ptr, salen, err = to.sockaddr()
449 if err != nil {
450 return 0, err
451 }
452 }
453 return sendmsgN(fd, iov, oob, ptr, salen, flags)
454}
455
456func Send(s int, buf []byte, flags int) (err error) {
457 return sendto(s, buf, flags, nil, 0)
458}
459
460func Sendto(fd int, p []byte, flags int, to Sockaddr) (err error) {
461 var ptr unsafe.Pointer
462 var salen _Socklen
463 if to != nil {
464 ptr, salen, err = to.sockaddr()
465 if err != nil {
466 return err
467 }
468 }
469 return sendto(fd, p, flags, ptr, salen)
470}
471
472func SetsockoptByte(fd, level, opt int, value byte) (err error) {
473 return setsockopt(fd, level, opt, unsafe.Pointer(&value), 1)
474}
475
476func SetsockoptInt(fd, level, opt int, value int) (err error) {
477 var n = int32(value)
478 return setsockopt(fd, level, opt, unsafe.Pointer(&n), 4)
479}
480
481func SetsockoptInet4Addr(fd, level, opt int, value [4]byte) (err error) {
482 return setsockopt(fd, level, opt, unsafe.Pointer(&value[0]), 4)
483}
484
485func SetsockoptIPMreq(fd, level, opt int, mreq *IPMreq) (err error) {
486 return setsockopt(fd, level, opt, unsafe.Pointer(mreq), SizeofIPMreq)
487}
488
489func SetsockoptIPv6Mreq(fd, level, opt int, mreq *IPv6Mreq) (err error) {
490 return setsockopt(fd, level, opt, unsafe.Pointer(mreq), SizeofIPv6Mreq)
491}
492
493func SetsockoptICMPv6Filter(fd, level, opt int, filter *ICMPv6Filter) error {
494 return setsockopt(fd, level, opt, unsafe.Pointer(filter), SizeofICMPv6Filter)
495}
496
497func SetsockoptLinger(fd, level, opt int, l *Linger) (err error) {
498 return setsockopt(fd, level, opt, unsafe.Pointer(l), SizeofLinger)
499}
500
501func SetsockoptString(fd, level, opt int, s string) (err error) {
502 var p unsafe.Pointer
503 if len(s) > 0 {
504 p = unsafe.Pointer(&[]byte(s)[0])
505 }
506 return setsockopt(fd, level, opt, p, uintptr(len(s)))
507}
508
509func SetsockoptTimeval(fd, level, opt int, tv *Timeval) (err error) {
510 return setsockopt(fd, level, opt, unsafe.Pointer(tv), unsafe.Sizeof(*tv))
511}
512
513func SetsockoptUint64(fd, level, opt int, value uint64) (err error) {
514 return setsockopt(fd, level, opt, unsafe.Pointer(&value), 8)
515}
516
517func Socket(domain, typ, proto int) (fd int, err error) {
518 if domain == AF_INET6 && SocketDisableIPv6 {
519 return -1, EAFNOSUPPORT
520 }
521 fd, err = socket(domain, typ, proto)
522 return
523}
524
525func Socketpair(domain, typ, proto int) (fd [2]int, err error) {
526 var fdx [2]int32
527 err = socketpair(domain, typ, proto, &fdx)
528 if err == nil {
529 fd[0] = int(fdx[0])
530 fd[1] = int(fdx[1])
531 }
532 return
533}
534
535var ioSync int64
536
537func CloseOnExec(fd int) { fcntl(fd, F_SETFD, FD_CLOEXEC) }
538
539func SetNonblock(fd int, nonblocking bool) (err error) {
540 flag, err := fcntl(fd, F_GETFL, 0)
541 if err != nil {
542 return err
543 }
544 if nonblocking {
545 flag |= O_NONBLOCK
546 } else {
547 flag &= ^O_NONBLOCK
548 }
549 _, err = fcntl(fd, F_SETFL, flag)
550 return err
551}
552
553// Exec calls execve(2), which replaces the calling executable in the process
554// tree. argv0 should be the full path to an executable ("/bin/ls") and the
555// executable name should also be the first argument in argv (["ls", "-l"]).
556// envv are the environment variables that should be passed to the new
557// process (["USER=go", "PWD=/tmp"]).
558func Exec(argv0 string, argv []string, envv []string) error {
559 return syscall.Exec(argv0, argv, envv)
560}
561
562// Lutimes sets the access and modification times tv on path. If path refers to
563// a symlink, it is not dereferenced and the timestamps are set on the symlink.
564// If tv is nil, the access and modification times are set to the current time.
565// Otherwise tv must contain exactly 2 elements, with access time as the first
566// element and modification time as the second element.
567func Lutimes(path string, tv []Timeval) error {
568 if tv == nil {
569 return UtimesNanoAt(AT_FDCWD, path, nil, AT_SYMLINK_NOFOLLOW)
570 }
571 if len(tv) != 2 {
572 return EINVAL
573 }
574 ts := []Timespec{
575 NsecToTimespec(TimevalToNsec(tv[0])),
576 NsecToTimespec(TimevalToNsec(tv[1])),
577 }
578 return UtimesNanoAt(AT_FDCWD, path, ts, AT_SYMLINK_NOFOLLOW)
579}
580
581// emptyIovecs reports whether there are no bytes in the slice of Iovec.
582func emptyIovecs(iov []Iovec) bool {
583 for i := range iov {
584 if iov[i].Len > 0 {
585 return false
586 }
587 }
588 return true
589}
590
591// Setrlimit sets a resource limit.
592func Setrlimit(resource int, rlim *Rlimit) error {
593 // Just call the syscall version, because as of Go 1.21
594 // it will affect starting a new process.
595 return syscall.Setrlimit(resource, (*syscall.Rlimit)(rlim))
596}