92 lines
2.0 KiB
Go
92 lines
2.0 KiB
Go
// Copyright 2011 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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// Plan 9 environment variables.
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package os
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import "syscall"
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// ENOENV is the Error indicating that an environment variable does not exist.
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var ENOENV = NewError("no such environment variable")
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// Getenverror retrieves the value of the environment variable named by the key.
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// It returns the value and an error, if any.
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func Getenverror(key string) (value string, err Error) {
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if len(key) == 0 {
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return "", EINVAL
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}
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f, e := Open("/env/" + key)
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if iserror(e) {
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return "", ENOENV
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}
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defer f.Close()
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var buf [4096]byte
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n, e := f.Read(buf[:len(buf)-1])
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if iserror(e) {
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return "", ENOENV
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}
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buf[n] = 0
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return string(buf[0:n]), nil
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}
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// Getenv retrieves the value of the environment variable named by the key.
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// It returns the value, which will be empty if the variable is not present.
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func Getenv(key string) string {
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v, _ := Getenverror(key)
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return v
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}
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// Setenv sets the value of the environment variable named by the key.
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// It returns an Error, if any.
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func Setenv(key, value string) Error {
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if len(key) == 0 {
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return EINVAL
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}
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f, e := Create("/env/" + key)
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if iserror(e) {
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return e
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}
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defer f.Close()
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_, e = f.Write(syscall.StringByteSlice(value))
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return nil
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}
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// Clearenv deletes all environment variables.
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func Clearenv() {
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syscall.RawSyscall(syscall.SYS_RFORK, syscall.RFCENVG, 0, 0)
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}
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// Environ returns an array of strings representing the environment,
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// in the form "key=value".
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func Environ() []string {
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env := make([]string, 0, 100)
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f, e := Open("/env")
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if iserror(e) {
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panic(e)
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}
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defer f.Close()
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names, e := f.Readdirnames(-1)
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if iserror(e) {
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panic(e)
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}
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for _, k := range names {
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if v, e := Getenverror(k); !iserror(e) {
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env = append(env, k+"="+v)
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}
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}
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return env[0:len(env)]
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}
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// TempDir returns the default directory to use for temporary files.
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func TempDir() string {
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return "/tmp"
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}
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