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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build darwin freebsd linux netbsd openbsd
package syscall
import (
"runtime"
"sync"
"unsafe"
)
var (
Stdin = 0
Stdout = 1
Stderr = 2
)
const darwinAMD64 = runtime.GOOS == "darwin" && runtime.GOARCH == "amd64"
func Syscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno)
func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno)
func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno)
func RawSyscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno)
// Mmap manager, for use by operating system-specific implementations.
type mmapper struct {
sync.Mutex
active map[*byte][]byte // active mappings; key is last byte in mapping
mmap func(addr, length uintptr, prot, flags, fd int, offset int64) (uintptr, error)
munmap func(addr uintptr, length uintptr) error
}
func (m *mmapper) Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
if length <= 0 {
return nil, EINVAL
}
// Map the requested memory.
addr, errno := m.mmap(0, uintptr(length), prot, flags, fd, offset)
if errno != nil {
return nil, errno
}
// Slice memory layout
var sl = struct {
addr uintptr
len int
cap int
}{addr, length, length}
// Use unsafe to turn sl into a []byte.
b := *(*[]byte)(unsafe.Pointer(&sl))
// Register mapping in m and return it.
p := &b[cap(b)-1]
m.Lock()
defer m.Unlock()
m.active[p] = b
return b, nil
}
func (m *mmapper) Munmap(data []byte) (err error) {
if len(data) == 0 || len(data) != cap(data) {
return EINVAL
}
// Find the base of the mapping.
p := &data[cap(data)-1]
m.Lock()
defer m.Unlock()
b := m.active[p]
if b == nil || &b[0] != &data[0] {
return EINVAL
}
// Unmap the memory and update m.
if errno := m.munmap(uintptr(unsafe.Pointer(&b[0])), uintptr(len(b))); errno != nil {
return errno
}
delete(m.active, p)
return nil
}
// An Errno is an unsigned number describing an error condition.
// It implements the error interface. The zero Errno is by convention
// a non-error, so code to convert from Errno to error should use:
// err = nil
// if errno != 0 {
// err = errno
// }
type Errno uintptr
func (e Errno) Error() string {
if 0 <= e && int(e) < len(errors) {
s := errors[e]
if s != "" {
return s
}
}
return "errno " + itoa(int(e))
}
func (e Errno) Temporary() bool {
return e == EINTR || e == EMFILE || e.Timeout()
}
func (e Errno) Timeout() bool {
return e == EAGAIN || e == EWOULDBLOCK || e == ETIMEDOUT
}
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