github.com/Andyfoo/golang/x/sys@v0.0.0-20190901054642-57c1bf301704/unix/syscall_unix.go (about)

     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  // +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
     6  
     7  package unix
     8  
     9  import (
    10  	"bytes"
    11  	"sort"
    12  	"sync"
    13  	"syscall"
    14  	"unsafe"
    15  )
    16  
    17  var (
    18  	Stdin  = 0
    19  	Stdout = 1
    20  	Stderr = 2
    21  )
    22  
    23  // Do the interface allocations only once for common
    24  // Errno values.
    25  var (
    26  	errEAGAIN error = syscall.EAGAIN
    27  	errEINVAL error = syscall.EINVAL
    28  	errENOENT error = syscall.ENOENT
    29  )
    30  
    31  var (
    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.
    38  func 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.
    53  func 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.
    64  func 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".
    77  func SignalNum(s string) syscall.Signal {
    78  	signalNameMapOnce.Do(func() {
    79  		signalNameMap = make(map[string]syscall.Signal)
    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.
    88  func 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  
    98  type 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  
   105  func (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  	// Slice memory layout
   117  	var sl = struct {
   118  		addr uintptr
   119  		len  int
   120  		cap  int
   121  	}{addr, length, length}
   122  
   123  	// Use unsafe to turn sl into a []byte.
   124  	b := *(*[]byte)(unsafe.Pointer(&sl))
   125  
   126  	// Register mapping in m and return it.
   127  	p := &b[cap(b)-1]
   128  	m.Lock()
   129  	defer m.Unlock()
   130  	m.active[p] = b
   131  	return b, nil
   132  }
   133  
   134  func (m *mmapper) Munmap(data []byte) (err error) {
   135  	if len(data) == 0 || len(data) != cap(data) {
   136  		return EINVAL
   137  	}
   138  
   139  	// Find the base of the mapping.
   140  	p := &data[cap(data)-1]
   141  	m.Lock()
   142  	defer m.Unlock()
   143  	b := m.active[p]
   144  	if b == nil || &b[0] != &data[0] {
   145  		return EINVAL
   146  	}
   147  
   148  	// Unmap the memory and update m.
   149  	if errno := m.munmap(uintptr(unsafe.Pointer(&b[0])), uintptr(len(b))); errno != nil {
   150  		return errno
   151  	}
   152  	delete(m.active, p)
   153  	return nil
   154  }
   155  
   156  func Read(fd int, p []byte) (n int, err error) {
   157  	n, err = read(fd, p)
   158  	if raceenabled {
   159  		if n > 0 {
   160  			raceWriteRange(unsafe.Pointer(&p[0]), n)
   161  		}
   162  		if err == nil {
   163  			raceAcquire(unsafe.Pointer(&ioSync))
   164  		}
   165  	}
   166  	return
   167  }
   168  
   169  func Write(fd int, p []byte) (n int, err error) {
   170  	if raceenabled {
   171  		raceReleaseMerge(unsafe.Pointer(&ioSync))
   172  	}
   173  	n, err = write(fd, p)
   174  	if raceenabled && n > 0 {
   175  		raceReadRange(unsafe.Pointer(&p[0]), n)
   176  	}
   177  	return
   178  }
   179  
   180  // For testing: clients can set this flag to force
   181  // creation of IPv6 sockets to return EAFNOSUPPORT.
   182  var SocketDisableIPv6 bool
   183  
   184  // Sockaddr represents a socket address.
   185  type Sockaddr interface {
   186  	sockaddr() (ptr unsafe.Pointer, len _Socklen, err error) // lowercase; only we can define Sockaddrs
   187  }
   188  
   189  // SockaddrInet4 implements the Sockaddr interface for AF_INET type sockets.
   190  type SockaddrInet4 struct {
   191  	Port int
   192  	Addr [4]byte
   193  	raw  RawSockaddrInet4
   194  }
   195  
   196  // SockaddrInet6 implements the Sockaddr interface for AF_INET6 type sockets.
   197  type SockaddrInet6 struct {
   198  	Port   int
   199  	ZoneId uint32
   200  	Addr   [16]byte
   201  	raw    RawSockaddrInet6
   202  }
   203  
   204  // SockaddrUnix implements the Sockaddr interface for AF_UNIX type sockets.
   205  type SockaddrUnix struct {
   206  	Name string
   207  	raw  RawSockaddrUnix
   208  }
   209  
   210  func Bind(fd int, sa Sockaddr) (err error) {
   211  	ptr, n, err := sa.sockaddr()
   212  	if err != nil {
   213  		return err
   214  	}
   215  	return bind(fd, ptr, n)
   216  }
   217  
   218  func Connect(fd int, sa Sockaddr) (err error) {
   219  	ptr, n, err := sa.sockaddr()
   220  	if err != nil {
   221  		return err
   222  	}
   223  	return connect(fd, ptr, n)
   224  }
   225  
   226  func Getpeername(fd int) (sa Sockaddr, err error) {
   227  	var rsa RawSockaddrAny
   228  	var len _Socklen = SizeofSockaddrAny
   229  	if err = getpeername(fd, &rsa, &len); err != nil {
   230  		return
   231  	}
   232  	return anyToSockaddr(fd, &rsa)
   233  }
   234  
   235  func GetsockoptByte(fd, level, opt int) (value byte, err error) {
   236  	var n byte
   237  	vallen := _Socklen(1)
   238  	err = getsockopt(fd, level, opt, unsafe.Pointer(&n), &vallen)
   239  	return n, err
   240  }
   241  
   242  func GetsockoptInt(fd, level, opt int) (value int, err error) {
   243  	var n int32
   244  	vallen := _Socklen(4)
   245  	err = getsockopt(fd, level, opt, unsafe.Pointer(&n), &vallen)
   246  	return int(n), err
   247  }
   248  
   249  func GetsockoptInet4Addr(fd, level, opt int) (value [4]byte, err error) {
   250  	vallen := _Socklen(4)
   251  	err = getsockopt(fd, level, opt, unsafe.Pointer(&value[0]), &vallen)
   252  	return value, err
   253  }
   254  
   255  func GetsockoptIPMreq(fd, level, opt int) (*IPMreq, error) {
   256  	var value IPMreq
   257  	vallen := _Socklen(SizeofIPMreq)
   258  	err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
   259  	return &value, err
   260  }
   261  
   262  func GetsockoptIPv6Mreq(fd, level, opt int) (*IPv6Mreq, error) {
   263  	var value IPv6Mreq
   264  	vallen := _Socklen(SizeofIPv6Mreq)
   265  	err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
   266  	return &value, err
   267  }
   268  
   269  func GetsockoptIPv6MTUInfo(fd, level, opt int) (*IPv6MTUInfo, error) {
   270  	var value IPv6MTUInfo
   271  	vallen := _Socklen(SizeofIPv6MTUInfo)
   272  	err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
   273  	return &value, err
   274  }
   275  
   276  func GetsockoptICMPv6Filter(fd, level, opt int) (*ICMPv6Filter, error) {
   277  	var value ICMPv6Filter
   278  	vallen := _Socklen(SizeofICMPv6Filter)
   279  	err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
   280  	return &value, err
   281  }
   282  
   283  func GetsockoptLinger(fd, level, opt int) (*Linger, error) {
   284  	var linger Linger
   285  	vallen := _Socklen(SizeofLinger)
   286  	err := getsockopt(fd, level, opt, unsafe.Pointer(&linger), &vallen)
   287  	return &linger, err
   288  }
   289  
   290  func GetsockoptTimeval(fd, level, opt int) (*Timeval, error) {
   291  	var tv Timeval
   292  	vallen := _Socklen(unsafe.Sizeof(tv))
   293  	err := getsockopt(fd, level, opt, unsafe.Pointer(&tv), &vallen)
   294  	return &tv, err
   295  }
   296  
   297  func GetsockoptUint64(fd, level, opt int) (value uint64, err error) {
   298  	var n uint64
   299  	vallen := _Socklen(8)
   300  	err = getsockopt(fd, level, opt, unsafe.Pointer(&n), &vallen)
   301  	return n, err
   302  }
   303  
   304  func Recvfrom(fd int, p []byte, flags int) (n int, from Sockaddr, err error) {
   305  	var rsa RawSockaddrAny
   306  	var len _Socklen = SizeofSockaddrAny
   307  	if n, err = recvfrom(fd, p, flags, &rsa, &len); err != nil {
   308  		return
   309  	}
   310  	if rsa.Addr.Family != AF_UNSPEC {
   311  		from, err = anyToSockaddr(fd, &rsa)
   312  	}
   313  	return
   314  }
   315  
   316  func Sendto(fd int, p []byte, flags int, to Sockaddr) (err error) {
   317  	ptr, n, err := to.sockaddr()
   318  	if err != nil {
   319  		return err
   320  	}
   321  	return sendto(fd, p, flags, ptr, n)
   322  }
   323  
   324  func SetsockoptByte(fd, level, opt int, value byte) (err error) {
   325  	return setsockopt(fd, level, opt, unsafe.Pointer(&value), 1)
   326  }
   327  
   328  func SetsockoptInt(fd, level, opt int, value int) (err error) {
   329  	var n = int32(value)
   330  	return setsockopt(fd, level, opt, unsafe.Pointer(&n), 4)
   331  }
   332  
   333  func SetsockoptInet4Addr(fd, level, opt int, value [4]byte) (err error) {
   334  	return setsockopt(fd, level, opt, unsafe.Pointer(&value[0]), 4)
   335  }
   336  
   337  func SetsockoptIPMreq(fd, level, opt int, mreq *IPMreq) (err error) {
   338  	return setsockopt(fd, level, opt, unsafe.Pointer(mreq), SizeofIPMreq)
   339  }
   340  
   341  func SetsockoptIPv6Mreq(fd, level, opt int, mreq *IPv6Mreq) (err error) {
   342  	return setsockopt(fd, level, opt, unsafe.Pointer(mreq), SizeofIPv6Mreq)
   343  }
   344  
   345  func SetsockoptICMPv6Filter(fd, level, opt int, filter *ICMPv6Filter) error {
   346  	return setsockopt(fd, level, opt, unsafe.Pointer(filter), SizeofICMPv6Filter)
   347  }
   348  
   349  func SetsockoptLinger(fd, level, opt int, l *Linger) (err error) {
   350  	return setsockopt(fd, level, opt, unsafe.Pointer(l), SizeofLinger)
   351  }
   352  
   353  func SetsockoptString(fd, level, opt int, s string) (err error) {
   354  	var p unsafe.Pointer
   355  	if len(s) > 0 {
   356  		p = unsafe.Pointer(&[]byte(s)[0])
   357  	}
   358  	return setsockopt(fd, level, opt, p, uintptr(len(s)))
   359  }
   360  
   361  func SetsockoptTimeval(fd, level, opt int, tv *Timeval) (err error) {
   362  	return setsockopt(fd, level, opt, unsafe.Pointer(tv), unsafe.Sizeof(*tv))
   363  }
   364  
   365  func SetsockoptUint64(fd, level, opt int, value uint64) (err error) {
   366  	return setsockopt(fd, level, opt, unsafe.Pointer(&value), 8)
   367  }
   368  
   369  func Socket(domain, typ, proto int) (fd int, err error) {
   370  	if domain == AF_INET6 && SocketDisableIPv6 {
   371  		return -1, EAFNOSUPPORT
   372  	}
   373  	fd, err = socket(domain, typ, proto)
   374  	return
   375  }
   376  
   377  func Socketpair(domain, typ, proto int) (fd [2]int, err error) {
   378  	var fdx [2]int32
   379  	err = socketpair(domain, typ, proto, &fdx)
   380  	if err == nil {
   381  		fd[0] = int(fdx[0])
   382  		fd[1] = int(fdx[1])
   383  	}
   384  	return
   385  }
   386  
   387  var ioSync int64
   388  
   389  func CloseOnExec(fd int) { fcntl(fd, F_SETFD, FD_CLOEXEC) }
   390  
   391  func SetNonblock(fd int, nonblocking bool) (err error) {
   392  	flag, err := fcntl(fd, F_GETFL, 0)
   393  	if err != nil {
   394  		return err
   395  	}
   396  	if nonblocking {
   397  		flag |= O_NONBLOCK
   398  	} else {
   399  		flag &= ^O_NONBLOCK
   400  	}
   401  	_, err = fcntl(fd, F_SETFL, flag)
   402  	return err
   403  }
   404  
   405  // Exec calls execve(2), which replaces the calling executable in the process
   406  // tree. argv0 should be the full path to an executable ("/bin/ls") and the
   407  // executable name should also be the first argument in argv (["ls", "-l"]).
   408  // envv are the environment variables that should be passed to the new
   409  // process (["USER=go", "PWD=/tmp"]).
   410  func Exec(argv0 string, argv []string, envv []string) error {
   411  	return syscall.Exec(argv0, argv, envv)
   412  }
   413  
   414  // Lutimes sets the access and modification times tv on path. If path refers to
   415  // a symlink, it is not dereferenced and the timestamps are set on the symlink.
   416  // If tv is nil, the access and modification times are set to the current time.
   417  // Otherwise tv must contain exactly 2 elements, with access time as the first
   418  // element and modification time as the second element.
   419  func Lutimes(path string, tv []Timeval) error {
   420  	if tv == nil {
   421  		return UtimesNanoAt(AT_FDCWD, path, nil, AT_SYMLINK_NOFOLLOW)
   422  	}
   423  	if len(tv) != 2 {
   424  		return EINVAL
   425  	}
   426  	ts := []Timespec{
   427  		NsecToTimespec(TimevalToNsec(tv[0])),
   428  		NsecToTimespec(TimevalToNsec(tv[1])),
   429  	}
   430  	return UtimesNanoAt(AT_FDCWD, path, ts, AT_SYMLINK_NOFOLLOW)
   431  }