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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 (
"sync"
"unsafe"
)
var (
Stdin = 0
Stdout = 1
Stderr = 2
)
func c_syscall32(trap int32, a1, a2, a3, a4, a5, a6 int32) int32 __asm__ ("syscall");
func c_syscall64(trap int64, a1, a2, a3, a4, a5, a6 int64) int64 __asm__ ("syscall");
// Do a system call. We look at the size of uintptr to see how to pass
// the arguments, so that we don't pass a 64-bit value when the function
// expects a 32-bit one.
func Syscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno) {
entersyscall()
var r uintptr
if unsafe.Sizeof(r) == 4 {
r1 := c_syscall32(int32(trap), int32(a1), int32(a2), int32(a3), 0, 0, 0)
r = uintptr(r1)
} else {
r1 := c_syscall64(int64(trap), int64(a1), int64(a2), int64(a3), 0, 0, 0)
r = uintptr(r1)
}
err = GetErrno()
exitsyscall()
return r, 0, err
}
func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno) {
entersyscall()
var r uintptr
if unsafe.Sizeof(r) == 4 {
r1 := c_syscall32(int32(trap), int32(a1), int32(a2), int32(a3),
int32(a4), int32(a5), int32(a6))
r = uintptr(r1)
} else {
r1 := c_syscall64(int64(trap), int64(a1), int64(a2), int64(a3),
int64(a4), int64(a5), int64(a6))
r = uintptr(r1)
}
err = GetErrno()
exitsyscall()
return r, 0, err
}
func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno) {
var r uintptr
if unsafe.Sizeof(r) == 4 {
r1 := c_syscall32(int32(trap), int32(a1), int32(a2), int32(a3), 0, 0, 0)
r = uintptr(r1)
} else {
r1 := c_syscall64(int64(trap), int64(a1), int64(a2), int64(a3), 0, 0, 0)
r = uintptr(r1)
}
err = GetErrno()
return r, 0, err
}
func RawSyscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno) {
var r uintptr
if unsafe.Sizeof(r) == 4 {
r1 := c_syscall32(int32(trap), int32(a1), int32(a2), int32(a3),
int32(a4), int32(a5), int32(a6))
r = uintptr(r1)
} else {
r1 := c_syscall64(int64(trap), int64(a1), int64(a2), int64(a3),
int64(a4), int64(a5), int64(a6))
r = uintptr(r1)
}
err = GetErrno()
return r, 0, err
}
// Mmap manager, for use by operating system-specific implementations.
// Gccgo only has one implementation but we do this to correspond to gc.
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
}
m.active[p] = nil, false
return nil
}
var mapper = &mmapper{
active: make(map[*byte][]byte),
mmap: mmap,
munmap: munmap,
}
func Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
return mapper.Mmap(fd, offset, length, prot, flags)
}
func Munmap(b []byte) (err error) {
return mapper.Munmap(b)
}
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