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 dragonfly 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 (
  28         darwin64Bit = runtime.GOOS == "darwin" && sizeofPtr == 8
  29         netbsd32Bit = runtime.GOOS == "netbsd" && sizeofPtr == 4
  30 )
  31
  32 // Do a system call.  We look at the size of uintptr to see how to pass
  33 // the arguments, so that we don't pass a 64-bit value when the function
  34 // expects a 32-bit one.
  35 func Syscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno) {
  36         Entersyscall()
  37         SetErrno(0)
  38         var r uintptr
  39         if unsafe.Sizeof(r) == 4 {
  40                 r1 := c_syscall32(int32(trap), int32(a1), int32(a2), int32(a3), 0, 0, 0)
  41                 r = uintptr(r1)
  42         } else {
  43                 r1 := c_syscall64(int64(trap), int64(a1), int64(a2), int64(a3), 0, 0, 0)
  44                 r = uintptr(r1)
  45         }
  46         err = GetErrno()
  47         Exitsyscall()
  48         return r, 0, err
  49 }
  50
  51 func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno) {
  52         Entersyscall()
  53         SetErrno(0)
  54         var r uintptr
  55         if unsafe.Sizeof(r) == 4 {
  56                 r1 := c_syscall32(int32(trap), int32(a1), int32(a2), int32(a3),
  57                         int32(a4), int32(a5), int32(a6))
  58                 r = uintptr(r1)
  59         } else {
  60                 r1 := c_syscall64(int64(trap), int64(a1), int64(a2), int64(a3),
  61                         int64(a4), int64(a5), int64(a6))
  62                 r = uintptr(r1)
  63         }
  64         err = GetErrno()
  65         Exitsyscall()
  66         return r, 0, err
  67 }
  68
  69 func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno) {
  70         var r uintptr
  71         SetErrno(0)
  72         if unsafe.Sizeof(r) == 4 {
  73                 r1 := c_syscall32(int32(trap), int32(a1), int32(a2), int32(a3), 0, 0, 0)
  74                 r = uintptr(r1)
  75         } else {
  76                 r1 := c_syscall64(int64(trap), int64(a1), int64(a2), int64(a3), 0, 0, 0)
  77                 r = uintptr(r1)
  78         }
  79         err = GetErrno()
  80         return r, 0, err
  81 }
  82
  83 func RawSyscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno) {
  84         var r uintptr
  85         SetErrno(0)
  86         if unsafe.Sizeof(r) == 4 {
  87                 r1 := c_syscall32(int32(trap), int32(a1), int32(a2), int32(a3),
  88                         int32(a4), int32(a5), int32(a6))
  89                 r = uintptr(r1)
  90         } else {
  91                 r1 := c_syscall64(int64(trap), int64(a1), int64(a2), int64(a3),
  92                         int64(a4), int64(a5), int64(a6))
  93                 r = uintptr(r1)
  94         }
  95         err = GetErrno()
  96         return r, 0, err
  97 }
  98
  99 // Mmap manager, for use by operating system-specific implementations.
 100 // Gccgo only has one implementation but we do this to correspond to gc.
 101
 102 type mmapper struct {
 103         sync.Mutex
 104         active map[*byte][]byte // active mappings; key is last byte in mapping
 105         mmap   func(addr, length uintptr, prot, flags, fd int, offset int64) (uintptr, error)
 106         munmap func(addr uintptr, length uintptr) error
 107 }
 108
 109 func (m *mmapper) Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
 110         if length <= 0 {
 111                 return nil, EINVAL
 112         }
 113
 114         // Map the requested memory.
 115         addr, errno := m.mmap(0, uintptr(length), prot, flags, fd, offset)
 116         if errno != nil {
 117                 return nil, errno
 118         }
 119
 120         // Slice memory layout
 121         var sl = struct {
 122                 addr uintptr
 123                 len  int
 124                 cap  int
 125         }{addr, length, length}
 126
 127         // Use unsafe to turn sl into a []byte.
 128         b := *(*[]byte)(unsafe.Pointer(&sl))
 129
 130         // Register mapping in m and return it.
 131         p := &b[cap(b)-1]
 132         m.Lock()
 133         defer m.Unlock()
 134         m.active[p] = b
 135         return b, nil
 136 }
 137
 138 func (m *mmapper) Munmap(data []byte) (err error) {
 139         if len(data) == 0 || len(data) != cap(data) {
 140                 return EINVAL
 141         }
 142
 143         // Find the base of the mapping.
 144         p := &data[cap(data)-1]
 145         m.Lock()
 146         defer m.Unlock()
 147         b := m.active[p]
 148         if b == nil || &b[0] != &data[0] {
 149                 return EINVAL
 150         }
 151
 152         // Unmap the memory and update m.
 153         if errno := m.munmap(uintptr(unsafe.Pointer(&b[0])), uintptr(len(b))); errno != nil {
 154                 return errno
 155         }
 156         m.active[p] = nil, false
 157         return nil
 158 }
 159
 160 var mapper = &mmapper{
 161         active: make(map[*byte][]byte),
 162         mmap:   mmap,
 163         munmap: munmap,
 164 }
 165
 166 func Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
 167         return mapper.Mmap(fd, offset, length, prot, flags)
 168 }
 169
 170 func Munmap(b []byte) (err error) {
 171         return mapper.Munmap(b)
 172 }
 173
 174 // A Signal is a number describing a process signal.
 175 // It implements the os.Signal interface.
 176 type Signal int
 177
 178 func (s Signal) Signal() {}
 179
 180 func Signame(s Signal) string
 181
 182 func (s Signal) String() string {
 183         return Signame(s)
 184 }
 185
 186 func Read(fd int, p []byte) (n int, err error) {
 187         n, err = read(fd, p)
 188         if raceenabled {
 189                 if n > 0 {
 190                         raceWriteRange(unsafe.Pointer(&p[0]), n)
 191                 }
 192                 if err == nil {
 193                         raceAcquire(unsafe.Pointer(&ioSync))
 194                 }
 195         }
 196         return
 197 }
 198
 199 func Write(fd int, p []byte) (n int, err error) {
 200         if raceenabled {
 201                 raceReleaseMerge(unsafe.Pointer(&ioSync))
 202         }
 203         n, err = write(fd, p)
 204         if raceenabled && n > 0 {
 205                 raceReadRange(unsafe.Pointer(&p[0]), n)
 206         }
 207         return
 208 }
 209
 210 var ioSync int64