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95 lines
3.0 KiB
95 lines
3.0 KiB
// 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 || linux || netbsd || openbsd || solaris || zos |
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// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris zos |
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// Package unix contains an interface to the low-level operating system |
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// primitives. OS details vary depending on the underlying system, and |
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// by default, godoc will display OS-specific documentation for the current |
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// system. If you want godoc to display OS documentation for another |
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// system, set $GOOS and $GOARCH to the desired system. For example, if |
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// you want to view documentation for freebsd/arm on linux/amd64, set $GOOS |
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// to freebsd and $GOARCH to arm. |
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// |
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// The primary use of this package is inside other packages that provide a more |
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// portable interface to the system, such as "os", "time" and "net". Use |
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// those packages rather than this one if you can. |
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// |
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// For details of the functions and data types in this package consult |
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// the manuals for the appropriate operating system. |
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// |
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// These calls return err == nil to indicate success; otherwise |
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// err represents an operating system error describing the failure and |
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// holds a value of type syscall.Errno. |
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package unix // import "golang.org/x/sys/unix" |
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import ( |
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"bytes" |
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"strings" |
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"unsafe" |
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"golang.org/x/sys/internal/unsafeheader" |
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) |
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// ByteSliceFromString returns a NUL-terminated slice of bytes |
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// containing the text of s. If s contains a NUL byte at any |
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// location, it returns (nil, EINVAL). |
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func ByteSliceFromString(s string) ([]byte, error) { |
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if strings.IndexByte(s, 0) != -1 { |
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return nil, EINVAL |
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} |
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a := make([]byte, len(s)+1) |
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copy(a, s) |
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return a, nil |
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} |
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// BytePtrFromString returns a pointer to a NUL-terminated array of |
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// bytes containing the text of s. If s contains a NUL byte at any |
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// location, it returns (nil, EINVAL). |
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func BytePtrFromString(s string) (*byte, error) { |
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a, err := ByteSliceFromString(s) |
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if err != nil { |
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return nil, err |
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} |
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return &a[0], nil |
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} |
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// ByteSliceToString returns a string form of the text represented by the slice s, with a terminating NUL and any |
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// bytes after the NUL removed. |
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func ByteSliceToString(s []byte) string { |
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if i := bytes.IndexByte(s, 0); i != -1 { |
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s = s[:i] |
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} |
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return string(s) |
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} |
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// BytePtrToString takes a pointer to a sequence of text and returns the corresponding string. |
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// If the pointer is nil, it returns the empty string. It assumes that the text sequence is terminated |
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// at a zero byte; if the zero byte is not present, the program may crash. |
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func BytePtrToString(p *byte) string { |
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if p == nil { |
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return "" |
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} |
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if *p == 0 { |
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return "" |
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} |
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// Find NUL terminator. |
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n := 0 |
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for ptr := unsafe.Pointer(p); *(*byte)(ptr) != 0; n++ { |
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ptr = unsafe.Pointer(uintptr(ptr) + 1) |
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} |
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var s []byte |
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h := (*unsafeheader.Slice)(unsafe.Pointer(&s)) |
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h.Data = unsafe.Pointer(p) |
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h.Len = n |
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h.Cap = n |
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return string(s) |
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} |
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// Single-word zero for use when we need a valid pointer to 0 bytes. |
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var _zero uintptr
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