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
7package unix
8
9import (
10 "bytes"
11 "sort"
12 "sync"
13 "syscall"
14 "unsafe"
15)
16
17var (
18 Stdin = 0
19 Stdout = 1
20 Stderr = 2
21)
22
23// Do the interface allocations only once for common
24// Errno values.
25var (
26 errEAGAIN error = syscall.EAGAIN
27 errEINVAL error = syscall.EINVAL
28 errENOENT error = syscall.ENOENT
29)
30
31var (
32 signalNameMapOnce sync.Once
33 signalNameMap map[string]syscall.Signal
34)
35
36// errnoErr returns common boxed Errno values, to prevent
37// allocations at runtime.
38func errnoErr(e syscall.Errno) error {
39 switch e {
40 case 0:
41 return nil
42 case EAGAIN:
43 return errEAGAIN
44 case EINVAL:
45 return errEINVAL
46 case ENOENT:
47 return errENOENT
48 }
49 return e
50}
51
52// ErrnoName returns the error name for error number e.
53func ErrnoName(e syscall.Errno) string {
54 i := sort.Search(len(errorList), func(i int) bool {
55 return errorList[i].num >= e
56 })
57 if i < len(errorList) && errorList[i].num == e {
58 return errorList[i].name
59 }
60 return ""
61}
62
63// SignalName returns the signal name for signal number s.
64func SignalName(s syscall.Signal) string {
65 i := sort.Search(len(signalList), func(i int) bool {
66 return signalList[i].num >= s
67 })
68 if i < len(signalList) && signalList[i].num == s {
69 return signalList[i].name
70 }
71 return ""
72}
73
74// SignalNum returns the syscall.Signal for signal named s,
75// or 0 if a signal with such name is not found.
76// The signal name should start with "SIG".
77func SignalNum(s string) syscall.Signal {
78 signalNameMapOnce.Do(func() {
79 signalNameMap = make(map[string]syscall.Signal, len(signalList))
80 for _, signal := range signalList {
81 signalNameMap[signal.name] = signal.num
82 }
83 })
84 return signalNameMap[s]
85}
86
87// clen returns the index of the first NULL byte in n or len(n) if n contains no NULL byte.
88func clen(n []byte) int {
89 i := bytes.IndexByte(n, 0)
90 if i == -1 {
91 i = len(n)
92 }
93 return i
94}
95
96// Mmap manager, for use by operating system-specific implementations.
97
98type mmapper struct {
99 sync.Mutex
100 active map[*byte][]byte // active mappings; key is last byte in mapping
101 mmap func(addr, length uintptr, prot, flags, fd int, offset int64) (uintptr, error)
102 munmap func(addr uintptr, length uintptr) error
103}
104
105func (m *mmapper) Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
106 if length <= 0 {
107 return nil, EINVAL
108 }
109
110 // Map the requested memory.
111 addr, errno := m.mmap(0, uintptr(length), prot, flags, fd, offset)
112 if errno != nil {
113 return nil, errno
114 }
115
116 // Use unsafe to convert addr into a []byte.
117 b := unsafe.Slice((*byte)(unsafe.Pointer(addr)), length)
118
119 // Register mapping in m and return it.
120 p := &b[cap(b)-1]
121 m.Lock()
122 defer m.Unlock()
123 m.active[p] = b
124 return b, nil
125}
126
127func (m *mmapper) Munmap(data []byte) (err error) {
128 if len(data) == 0 || len(data) != cap(data) {
129 return EINVAL
130 }
131
132 // Find the base of the mapping.
133 p := &data[cap(data)-1]
134 m.Lock()
135 defer m.Unlock()
136 b := m.active[p]
137 if b == nil || &b[0] != &data[0] {
138 return EINVAL
139 }
140
141 // Unmap the memory and update m.
142 if errno := m.munmap(uintptr(unsafe.Pointer(&b[0])), uintptr(len(b))); errno != nil {
143 return errno
144 }
145 delete(m.active, p)
146 return nil
147}
148
149func Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
150 return mapper.Mmap(fd, offset, length, prot, flags)
151}
152
153func Munmap(b []byte) (err error) {
154 return mapper.Munmap(b)
155}
156
157func MmapPtr(fd int, offset int64, addr unsafe.Pointer, length uintptr, prot int, flags int) (ret unsafe.Pointer, err error) {
158 xaddr, err := mapper.mmap(uintptr(addr), length, prot, flags, fd, offset)
159 return unsafe.Pointer(xaddr), err
160}
161
162func MunmapPtr(addr unsafe.Pointer, length uintptr) (err error) {
163 return mapper.munmap(uintptr(addr), length)
164}
165
166func Read(fd int, p []byte) (n int, err error) {
167 n, err = read(fd, p)
168 if raceenabled {
169 if n > 0 {
170 raceWriteRange(unsafe.Pointer(&p[0]), n)
171 }
172 if err == nil {
173 raceAcquire(unsafe.Pointer(&ioSync))
174 }
175 }
176 return
177}
178
179func Write(fd int, p []byte) (n int, err error) {
180 if raceenabled {
181 raceReleaseMerge(unsafe.Pointer(&ioSync))
182 }
183 n, err = write(fd, p)
184 if raceenabled && n > 0 {
185 raceReadRange(unsafe.Pointer(&p[0]), n)
186 }
187 return
188}
189
190func Pread(fd int, p []byte, offset int64) (n int, err error) {
191 n, err = pread(fd, p, offset)
192 if raceenabled {
193 if n > 0 {
194 raceWriteRange(unsafe.Pointer(&p[0]), n)
195 }
196 if err == nil {
197 raceAcquire(unsafe.Pointer(&ioSync))
198 }
199 }
200 return
201}
202
203func Pwrite(fd int, p []byte, offset int64) (n int, err error) {
204 if raceenabled {
205 raceReleaseMerge(unsafe.Pointer(&ioSync))
206 }
207 n, err = pwrite(fd, p, offset)
208 if raceenabled && n > 0 {
209 raceReadRange(unsafe.Pointer(&p[0]), n)
210 }
211 return
212}
213
214// For testing: clients can set this flag to force
215// creation of IPv6 sockets to return EAFNOSUPPORT.
216var SocketDisableIPv6 bool
217
218// Sockaddr represents a socket address.
219type Sockaddr interface {
220 sockaddr() (ptr unsafe.Pointer, len _Socklen, err error) // lowercase; only we can define Sockaddrs
221}
222
223// SockaddrInet4 implements the Sockaddr interface for AF_INET type sockets.
224type SockaddrInet4 struct {
225 Port int
226 Addr [4]byte
227 raw RawSockaddrInet4
228}
229
230// SockaddrInet6 implements the Sockaddr interface for AF_INET6 type sockets.
231type SockaddrInet6 struct {
232 Port int
233 ZoneId uint32
234 Addr [16]byte
235 raw RawSockaddrInet6
236}
237
238// SockaddrUnix implements the Sockaddr interface for AF_UNIX type sockets.
239type SockaddrUnix struct {
240 Name string
241 raw RawSockaddrUnix
242}
243
244func Bind(fd int, sa Sockaddr) (err error) {
245 ptr, n, err := sa.sockaddr()
246 if err != nil {
247 return err
248 }
249 return bind(fd, ptr, n)
250}
251
252func Connect(fd int, sa Sockaddr) (err error) {
253 ptr, n, err := sa.sockaddr()
254 if err != nil {
255 return err
256 }
257 return connect(fd, ptr, n)
258}
259
260func Getpeername(fd int) (sa Sockaddr, err error) {
261 var rsa RawSockaddrAny
262 var len _Socklen = SizeofSockaddrAny
263 if err = getpeername(fd, &rsa, &len); err != nil {
264 return
265 }
266 return anyToSockaddr(fd, &rsa)
267}
268
269func GetsockoptByte(fd, level, opt int) (value byte, err error) {
270 var n byte
271 vallen := _Socklen(1)
272 err = getsockopt(fd, level, opt, unsafe.Pointer(&n), &vallen)
273 return n, err
274}
275
276func GetsockoptInt(fd, level, opt int) (value int, err error) {
277 var n int32
278 vallen := _Socklen(4)
279 err = getsockopt(fd, level, opt, unsafe.Pointer(&n), &vallen)
280 return int(n), err
281}
282
283func GetsockoptInet4Addr(fd, level, opt int) (value [4]byte, err error) {
284 vallen := _Socklen(4)
285 err = getsockopt(fd, level, opt, unsafe.Pointer(&value[0]), &vallen)
286 return value, err
287}
288
289func GetsockoptIPMreq(fd, level, opt int) (*IPMreq, error) {
290 var value IPMreq
291 vallen := _Socklen(SizeofIPMreq)
292 err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
293 return &value, err
294}
295
296func GetsockoptIPv6Mreq(fd, level, opt int) (*IPv6Mreq, error) {
297 var value IPv6Mreq
298 vallen := _Socklen(SizeofIPv6Mreq)
299 err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
300 return &value, err
301}
302
303func GetsockoptIPv6MTUInfo(fd, level, opt int) (*IPv6MTUInfo, error) {
304 var value IPv6MTUInfo
305 vallen := _Socklen(SizeofIPv6MTUInfo)
306 err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
307 return &value, err
308}
309
310func GetsockoptICMPv6Filter(fd, level, opt int) (*ICMPv6Filter, error) {
311 var value ICMPv6Filter
312 vallen := _Socklen(SizeofICMPv6Filter)
313 err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
314 return &value, err
315}
316
317func GetsockoptLinger(fd, level, opt int) (*Linger, error) {
318 var linger Linger
319 vallen := _Socklen(SizeofLinger)
320 err := getsockopt(fd, level, opt, unsafe.Pointer(&linger), &vallen)
321 return &linger, err
322}
323
324func GetsockoptTimeval(fd, level, opt int) (*Timeval, error) {
325 var tv Timeval
326 vallen := _Socklen(unsafe.Sizeof(tv))
327 err := getsockopt(fd, level, opt, unsafe.Pointer(&tv), &vallen)
328 return &tv, err
329}
330
331func GetsockoptUint64(fd, level, opt int) (value uint64, err error) {
332 var n uint64
333 vallen := _Socklen(8)
334 err = getsockopt(fd, level, opt, unsafe.Pointer(&n), &vallen)
335 return n, err
336}
337
338func Recvfrom(fd int, p []byte, flags int) (n int, from Sockaddr, err error) {
339 var rsa RawSockaddrAny
340 var len _Socklen = SizeofSockaddrAny
341 if n, err = recvfrom(fd, p, flags, &rsa, &len); err != nil {
342 return
343 }
344 if rsa.Addr.Family != AF_UNSPEC {
345 from, err = anyToSockaddr(fd, &rsa)
346 }
347 return
348}
349
350// Recvmsg receives a message from a socket using the recvmsg system call. The
351// received non-control data will be written to p, and any "out of band"
352// control data will be written to oob. The flags are passed to recvmsg.
353//
354// The results are:
355// - n is the number of non-control data bytes read into p
356// - oobn is the number of control data bytes read into oob; this may be interpreted using [ParseSocketControlMessage]
357// - recvflags is flags returned by recvmsg
358// - from is the address of the sender
359//
360// If the underlying socket type is not SOCK_DGRAM, a received message
361// containing oob data and a single '\0' of non-control data is treated as if
362// the message contained only control data, i.e. n will be zero on return.
363func Recvmsg(fd int, p, oob []byte, flags int) (n, oobn int, recvflags int, from Sockaddr, err error) {
364 var iov [1]Iovec
365 if len(p) > 0 {
366 iov[0].Base = &p[0]
367 iov[0].SetLen(len(p))
368 }
369 var rsa RawSockaddrAny
370 if n, oobn, recvflags, err = recvmsgRaw(fd, iov[:], oob, flags, &rsa); err != nil {
371 return
372 }
373 // source address is only specified if the socket is unconnected
374 if rsa.Addr.Family != AF_UNSPEC {
375 from, err = anyToSockaddr(fd, &rsa)
376 }
377 return
378}
379
380// RecvmsgBuffers receives a message from a socket using the recvmsg system
381// call. This function is equivalent to Recvmsg, but non-control data read is
382// scattered into the buffers slices.
383func RecvmsgBuffers(fd int, buffers [][]byte, oob []byte, flags int) (n, oobn int, recvflags int, from Sockaddr, err error) {
384 iov := make([]Iovec, len(buffers))
385 for i := range buffers {
386 if len(buffers[i]) > 0 {
387 iov[i].Base = &buffers[i][0]
388 iov[i].SetLen(len(buffers[i]))
389 } else {
390 iov[i].Base = (*byte)(unsafe.Pointer(&_zero))
391 }
392 }
393 var rsa RawSockaddrAny
394 if n, oobn, recvflags, err = recvmsgRaw(fd, iov, oob, flags, &rsa); err != nil {
395 return
396 }
397 if rsa.Addr.Family != AF_UNSPEC {
398 from, err = anyToSockaddr(fd, &rsa)
399 }
400 return
401}
402
403// Sendmsg sends a message on a socket to an address using the sendmsg system
404// call. This function is equivalent to SendmsgN, but does not return the
405// number of bytes actually sent.
406func Sendmsg(fd int, p, oob []byte, to Sockaddr, flags int) (err error) {
407 _, err = SendmsgN(fd, p, oob, to, flags)
408 return
409}
410
411// SendmsgN sends a message on a socket to an address using the sendmsg system
412// call. p contains the non-control data to send, and oob contains the "out of
413// band" control data. The flags are passed to sendmsg. The number of
414// non-control bytes actually written to the socket is returned.
415//
416// Some socket types do not support sending control data without accompanying
417// non-control data. If p is empty, and oob contains control data, and the
418// underlying socket type is not SOCK_DGRAM, p will be treated as containing a
419// single '\0' and the return value will indicate zero bytes sent.
420//
421// The Go function Recvmsg, if called with an empty p and a non-empty oob,
422// will read and ignore this additional '\0'. If the message is received by
423// code that does not use Recvmsg, or that does not use Go at all, that code
424// will need to be written to expect and ignore the additional '\0'.
425//
426// If you need to send non-empty oob with p actually empty, and if the
427// underlying socket type supports it, you can do so via a raw system call as
428// follows:
429//
430// msg := &unix.Msghdr{
431// Control: &oob[0],
432// }
433// msg.SetControllen(len(oob))
434// n, _, errno := unix.Syscall(unix.SYS_SENDMSG, uintptr(fd), uintptr(unsafe.Pointer(msg)), flags)
435func SendmsgN(fd int, p, oob []byte, to Sockaddr, flags int) (n int, err error) {
436 var iov [1]Iovec
437 if len(p) > 0 {
438 iov[0].Base = &p[0]
439 iov[0].SetLen(len(p))
440 }
441 var ptr unsafe.Pointer
442 var salen _Socklen
443 if to != nil {
444 ptr, salen, err = to.sockaddr()
445 if err != nil {
446 return 0, err
447 }
448 }
449 return sendmsgN(fd, iov[:], oob, ptr, salen, flags)
450}
451
452// SendmsgBuffers sends a message on a socket to an address using the sendmsg
453// system call. This function is equivalent to SendmsgN, but the non-control
454// data is gathered from buffers.
455func SendmsgBuffers(fd int, buffers [][]byte, oob []byte, to Sockaddr, flags int) (n int, err error) {
456 iov := make([]Iovec, len(buffers))
457 for i := range buffers {
458 if len(buffers[i]) > 0 {
459 iov[i].Base = &buffers[i][0]
460 iov[i].SetLen(len(buffers[i]))
461 } else {
462 iov[i].Base = (*byte)(unsafe.Pointer(&_zero))
463 }
464 }
465 var ptr unsafe.Pointer
466 var salen _Socklen
467 if to != nil {
468 ptr, salen, err = to.sockaddr()
469 if err != nil {
470 return 0, err
471 }
472 }
473 return sendmsgN(fd, iov, oob, ptr, salen, flags)
474}
475
476func Send(s int, buf []byte, flags int) (err error) {
477 return sendto(s, buf, flags, nil, 0)
478}
479
480func Sendto(fd int, p []byte, flags int, to Sockaddr) (err error) {
481 var ptr unsafe.Pointer
482 var salen _Socklen
483 if to != nil {
484 ptr, salen, err = to.sockaddr()
485 if err != nil {
486 return err
487 }
488 }
489 return sendto(fd, p, flags, ptr, salen)
490}
491
492func SetsockoptByte(fd, level, opt int, value byte) (err error) {
493 return setsockopt(fd, level, opt, unsafe.Pointer(&value), 1)
494}
495
496func SetsockoptInt(fd, level, opt int, value int) (err error) {
497 var n = int32(value)
498 return setsockopt(fd, level, opt, unsafe.Pointer(&n), 4)
499}
500
501func SetsockoptInet4Addr(fd, level, opt int, value [4]byte) (err error) {
502 return setsockopt(fd, level, opt, unsafe.Pointer(&value[0]), 4)
503}
504
505func SetsockoptIPMreq(fd, level, opt int, mreq *IPMreq) (err error) {
506 return setsockopt(fd, level, opt, unsafe.Pointer(mreq), SizeofIPMreq)
507}
508
509func SetsockoptIPv6Mreq(fd, level, opt int, mreq *IPv6Mreq) (err error) {
510 return setsockopt(fd, level, opt, unsafe.Pointer(mreq), SizeofIPv6Mreq)
511}
512
513func SetsockoptICMPv6Filter(fd, level, opt int, filter *ICMPv6Filter) error {
514 return setsockopt(fd, level, opt, unsafe.Pointer(filter), SizeofICMPv6Filter)
515}
516
517func SetsockoptLinger(fd, level, opt int, l *Linger) (err error) {
518 return setsockopt(fd, level, opt, unsafe.Pointer(l), SizeofLinger)
519}
520
521func SetsockoptString(fd, level, opt int, s string) (err error) {
522 var p unsafe.Pointer
523 if len(s) > 0 {
524 p = unsafe.Pointer(&[]byte(s)[0])
525 }
526 return setsockopt(fd, level, opt, p, uintptr(len(s)))
527}
528
529func SetsockoptTimeval(fd, level, opt int, tv *Timeval) (err error) {
530 return setsockopt(fd, level, opt, unsafe.Pointer(tv), unsafe.Sizeof(*tv))
531}
532
533func SetsockoptUint64(fd, level, opt int, value uint64) (err error) {
534 return setsockopt(fd, level, opt, unsafe.Pointer(&value), 8)
535}
536
537func Socket(domain, typ, proto int) (fd int, err error) {
538 if domain == AF_INET6 && SocketDisableIPv6 {
539 return -1, EAFNOSUPPORT
540 }
541 fd, err = socket(domain, typ, proto)
542 return
543}
544
545func Socketpair(domain, typ, proto int) (fd [2]int, err error) {
546 var fdx [2]int32
547 err = socketpair(domain, typ, proto, &fdx)
548 if err == nil {
549 fd[0] = int(fdx[0])
550 fd[1] = int(fdx[1])
551 }
552 return
553}
554
555var ioSync int64
556
557func CloseOnExec(fd int) { fcntl(fd, F_SETFD, FD_CLOEXEC) }
558
559func SetNonblock(fd int, nonblocking bool) (err error) {
560 flag, err := fcntl(fd, F_GETFL, 0)
561 if err != nil {
562 return err
563 }
564 if (flag&O_NONBLOCK != 0) == nonblocking {
565 return nil
566 }
567 if nonblocking {
568 flag |= O_NONBLOCK
569 } else {
570 flag &= ^O_NONBLOCK
571 }
572 _, err = fcntl(fd, F_SETFL, flag)
573 return err
574}
575
576// Exec calls execve(2), which replaces the calling executable in the process
577// tree. argv0 should be the full path to an executable ("/bin/ls") and the
578// executable name should also be the first argument in argv (["ls", "-l"]).
579// envv are the environment variables that should be passed to the new
580// process (["USER=go", "PWD=/tmp"]).
581func Exec(argv0 string, argv []string, envv []string) error {
582 return syscall.Exec(argv0, argv, envv)
583}
584
585// Lutimes sets the access and modification times tv on path. If path refers to
586// a symlink, it is not dereferenced and the timestamps are set on the symlink.
587// If tv is nil, the access and modification times are set to the current time.
588// Otherwise tv must contain exactly 2 elements, with access time as the first
589// element and modification time as the second element.
590func Lutimes(path string, tv []Timeval) error {
591 if tv == nil {
592 return UtimesNanoAt(AT_FDCWD, path, nil, AT_SYMLINK_NOFOLLOW)
593 }
594 if len(tv) != 2 {
595 return EINVAL
596 }
597 ts := []Timespec{
598 NsecToTimespec(TimevalToNsec(tv[0])),
599 NsecToTimespec(TimevalToNsec(tv[1])),
600 }
601 return UtimesNanoAt(AT_FDCWD, path, ts, AT_SYMLINK_NOFOLLOW)
602}
603
604// emptyIovecs reports whether there are no bytes in the slice of Iovec.
605func emptyIovecs(iov []Iovec) bool {
606 for i := range iov {
607 if iov[i].Len > 0 {
608 return false
609 }
610 }
611 return true
612}
613
614// Setrlimit sets a resource limit.
615func Setrlimit(resource int, rlim *Rlimit) error {
616 // Just call the syscall version, because as of Go 1.21
617 // it will affect starting a new process.
618 return syscall.Setrlimit(resource, (*syscall.Rlimit)(rlim))
619}