libgo/go/syscall/syscall_unix.go

   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 darwin freebsd linux netbsd openbsd
   6
   7 package syscall
   8
   9 import (
  10         "runtime"
  11         "sync"
  12         "unsafe"
  13 )
  14
  15 var (
  16         Stdin  = 0
  17         Stdout = 1
  18         Stderr = 2
  19 )
  20
  21 //extern syscall
  22 func c_syscall32(trap int32, a1, a2, a3, a4, a5, a6 int32) int32
  23
  24 //extern syscall
  25 func c_syscall64(trap int64, a1, a2, a3, a4, a5, a6 int64) int64
  26
  27 const darwinAMD64 = runtime.GOOS == "darwin" && runtime.GOARCH == "amd64"
  28
  29 // Do a system call.  We look at the size of uintptr to see how to pass
  30 // the arguments, so that we don't pass a 64-bit value when the function
  31 // expects a 32-bit one.
  32 func Syscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno) {
  33         Entersyscall()
  34         SetErrno(0)
  35         var r uintptr
  36         if unsafe.Sizeof(r) == 4 {
  37                 r1 := c_syscall32(int32(trap), int32(a1), int32(a2), int32(a3), 0, 0, 0)
  38                 r = uintptr(r1)
  39         } else {
  40                 r1 := c_syscall64(int64(trap), int64(a1), int64(a2), int64(a3), 0, 0, 0)
  41                 r = uintptr(r1)
  42         }
  43         err = GetErrno()
  44         Exitsyscall()
  45         return r, 0, err
  46 }
  47
  48 func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno) {
  49         Entersyscall()
  50         SetErrno(0)
  51         var r uintptr
  52         if unsafe.Sizeof(r) == 4 {
  53                 r1 := c_syscall32(int32(trap), int32(a1), int32(a2), int32(a3),
  54                         int32(a4), int32(a5), int32(a6))
  55                 r = uintptr(r1)
  56         } else {
  57                 r1 := c_syscall64(int64(trap), int64(a1), int64(a2), int64(a3),
  58                         int64(a4), int64(a5), int64(a6))
  59                 r = uintptr(r1)
  60         }
  61         err = GetErrno()
  62         Exitsyscall()
  63         return r, 0, err
  64 }
  65
  66 func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno) {
  67         var r uintptr
  68         SetErrno(0)
  69         if unsafe.Sizeof(r) == 4 {
  70                 r1 := c_syscall32(int32(trap), int32(a1), int32(a2), int32(a3), 0, 0, 0)
  71                 r = uintptr(r1)
  72         } else {
  73                 r1 := c_syscall64(int64(trap), int64(a1), int64(a2), int64(a3), 0, 0, 0)
  74                 r = uintptr(r1)
  75         }
  76         err = GetErrno()
  77         return r, 0, err
  78 }
  79
  80 func RawSyscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno) {
  81         var r uintptr
  82         SetErrno(0)
  83         if unsafe.Sizeof(r) == 4 {
  84                 r1 := c_syscall32(int32(trap), int32(a1), int32(a2), int32(a3),
  85                         int32(a4), int32(a5), int32(a6))
  86                 r = uintptr(r1)
  87         } else {
  88                 r1 := c_syscall64(int64(trap), int64(a1), int64(a2), int64(a3),
  89                         int64(a4), int64(a5), int64(a6))
  90                 r = uintptr(r1)
  91         }
  92         err = GetErrno()
  93         return r, 0, err
  94 }
  95
  96 // Mmap manager, for use by operating system-specific implementations.
  97 // Gccgo only has one implementation but we do this to correspond to gc.
  98
  99 type 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
 106 func (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         // Slice memory layout
 118         var sl = struct {
 119                 addr uintptr
 120                 len  int
 121                 cap  int
 122         }{addr, length, length}
 123
 124         // Use unsafe to turn sl into a []byte.
 125         b := *(*[]byte)(unsafe.Pointer(&sl))
 126
 127         // Register mapping in m and return it.
 128         p := &b[cap(b)-1]
 129         m.Lock()
 130         defer m.Unlock()
 131         m.active[p] = b
 132         return b, nil
 133 }
 134
 135 func (m *mmapper) Munmap(data []byte) (err error) {
 136         if len(data) == 0 || len(data) != cap(data) {
 137                 return EINVAL
 138         }
 139
 140         // Find the base of the mapping.
 141         p := &data[cap(data)-1]
 142         m.Lock()
 143         defer m.Unlock()
 144         b := m.active[p]
 145         if b == nil || &b[0] != &data[0] {
 146                 return EINVAL
 147         }
 148
 149         // Unmap the memory and update m.
 150         if errno := m.munmap(uintptr(unsafe.Pointer(&b[0])), uintptr(len(b))); errno != nil {
 151                 return errno
 152         }
 153         m.active[p] = nil, false
 154         return nil
 155 }
 156
 157 var mapper = &mmapper{
 158         active: make(map[*byte][]byte),
 159         mmap:   mmap,
 160         munmap: munmap,
 161 }
 162
 163 func Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
 164         return mapper.Mmap(fd, offset, length, prot, flags)
 165 }
 166
 167 func Munmap(b []byte) (err error) {
 168         return mapper.Munmap(b)
 169 }
 170
 171 // A Signal is a number describing a process signal.
 172 // It implements the os.Signal interface.
 173 type Signal int
 174
 175 func (s Signal) Signal() {}
 176
 177 func Signame(s Signal) string
 178
 179 func (s Signal) String() string {
 180         return Signame(s)
 181 }
 182
 183 func Read(fd int, p []byte) (n int, err error) {
 184         n, err = read(fd, p)
 185         if raceenabled && err == nil {
 186                 raceAcquire(unsafe.Pointer(&ioSync))
 187         }
 188         return
 189 }
 190
 191 func Write(fd int, p []byte) (n int, err error) {
 192         if raceenabled {
 193                 raceReleaseMerge(unsafe.Pointer(&ioSync))
 194         }
 195         return write(fd, p)
 196 }
 197
 198 var ioSync int64