mirror of
https://github.com/autc04/Retro68.git
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190 lines
3.9 KiB
Go
190 lines
3.9 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//go:build aix || darwin || dragonfly || freebsd || hurd || linux || netbsd || openbsd || solaris
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package syscall
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import (
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"internal/race"
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"internal/unsafeheader"
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"runtime"
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"sync"
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"unsafe"
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)
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var (
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Stdin = 0
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Stdout = 1
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Stderr = 2
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)
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const (
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darwin64Bit = (runtime.GOOS == "darwin" || runtime.GOOS == "ios") && sizeofPtr == 8
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netbsd32Bit = runtime.GOOS == "netbsd" && sizeofPtr == 4
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)
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// clen returns the index of the first NULL byte in n or len(n) if n contains no NULL byte.
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func clen(n []byte) int {
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for i := 0; i < len(n); i++ {
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if n[i] == 0 {
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return i
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}
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}
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return len(n)
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}
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// Mmap manager, for use by operating system-specific implementations.
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// Gccgo only has one implementation but we do this to correspond to gc.
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type mmapper struct {
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sync.Mutex
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active map[*byte][]byte // active mappings; key is last byte in mapping
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mmap func(addr, length uintptr, prot, flags, fd int, offset int64) (uintptr, error)
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munmap func(addr uintptr, length uintptr) error
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}
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func (m *mmapper) Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
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if length <= 0 {
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return nil, EINVAL
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}
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// Map the requested memory.
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addr, errno := m.mmap(0, uintptr(length), prot, flags, fd, offset)
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if errno != nil {
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return nil, errno
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}
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// Use unsafe to turn addr into a []byte.
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var b []byte
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hdr := (*unsafeheader.Slice)(unsafe.Pointer(&b))
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hdr.Data = unsafe.Pointer(addr)
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hdr.Cap = length
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hdr.Len = length
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// Register mapping in m and return it.
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p := &b[cap(b)-1]
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m.Lock()
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defer m.Unlock()
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m.active[p] = b
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return b, nil
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}
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func (m *mmapper) Munmap(data []byte) (err error) {
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if len(data) == 0 || len(data) != cap(data) {
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return EINVAL
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}
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// Find the base of the mapping.
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p := &data[cap(data)-1]
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m.Lock()
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defer m.Unlock()
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b := m.active[p]
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if b == nil || &b[0] != &data[0] {
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return EINVAL
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}
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// Unmap the memory and update m.
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if errno := m.munmap(uintptr(unsafe.Pointer(&b[0])), uintptr(len(b))); errno != nil {
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return errno
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}
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delete(m.active, p)
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return nil
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}
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var mapper = &mmapper{
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active: make(map[*byte][]byte),
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mmap: mmap,
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munmap: munmap,
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}
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func Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
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return mapper.Mmap(fd, offset, length, prot, flags)
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}
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func Munmap(b []byte) (err error) {
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return mapper.Munmap(b)
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}
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// Do the interface allocations only once for common
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// Errno values.
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var (
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errEAGAIN error = EAGAIN
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errEINVAL error = EINVAL
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errENOENT error = ENOENT
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)
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// errnoErr returns common boxed Errno values, to prevent
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// allocations at runtime.
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func errnoErr(e Errno) error {
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switch e {
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case 0:
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return nil
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case EAGAIN:
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return errEAGAIN
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case EINVAL:
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return errEINVAL
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case ENOENT:
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return errENOENT
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}
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return e
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}
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// A Signal is a number describing a process signal.
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// It implements the os.Signal interface.
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type Signal int
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func (s Signal) Signal() {}
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func Signame(s Signal) string
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func (s Signal) String() string {
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return Signame(s)
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}
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func Read(fd int, p []byte) (n int, err error) {
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n, err = read(fd, p)
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if race.Enabled {
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if n > 0 {
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race.WriteRange(unsafe.Pointer(&p[0]), n)
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}
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if err == nil {
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race.Acquire(unsafe.Pointer(&ioSync))
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}
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}
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if msanenabled && n > 0 {
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msanWrite(unsafe.Pointer(&p[0]), n)
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}
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if asanenabled && n > 0 {
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asanWrite(unsafe.Pointer(&p[0]), n)
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}
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return
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}
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func Write(fd int, p []byte) (n int, err error) {
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if race.Enabled {
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race.ReleaseMerge(unsafe.Pointer(&ioSync))
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}
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if faketime && (fd == 1 || fd == 2) {
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n = faketimeWrite(fd, p)
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if n < 0 {
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n, err = 0, errnoErr(Errno(-n))
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}
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} else {
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n, err = write(fd, p)
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}
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if race.Enabled && n > 0 {
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race.ReadRange(unsafe.Pointer(&p[0]), n)
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}
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if msanenabled && n > 0 {
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msanRead(unsafe.Pointer(&p[0]), n)
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}
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if asanenabled && n > 0 {
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asanRead(unsafe.Pointer(&p[0]), n)
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}
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return
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}
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var ioSync int64
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