Brad Fitzpatrick | bc9748e | 2015-02-27 19:34:56 -0800 | [diff] [blame] | 1 | // Copyright 2015 The Go Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | // The working directory in Plan 9 is effectively per P, so different |
| 6 | // goroutines and even the same goroutine as it's rescheduled on |
| 7 | // different Ps can see different working directories. |
| 8 | // |
| 9 | // Instead, track a Go process-wide intent of the current working directory, |
| 10 | // and switch to it at important points. |
| 11 | |
| 12 | package syscall |
| 13 | |
| 14 | import "sync" |
| 15 | |
| 16 | var ( |
| 17 | wdmu sync.Mutex // guards following |
| 18 | wdSet bool |
| 19 | wdStr string |
| 20 | ) |
| 21 | |
| 22 | func Fixwd() { |
| 23 | wdmu.Lock() |
| 24 | defer wdmu.Unlock() |
| 25 | fixwdLocked() |
| 26 | } |
| 27 | |
| 28 | func fixwdLocked() { |
| 29 | if !wdSet { |
| 30 | return |
| 31 | } |
David du Colombier | 7d3f81a | 2015-04-11 14:58:42 +0200 | [diff] [blame] | 32 | // always call chdir when getwd returns an error |
| 33 | wd, _ := getwd() |
Brad Fitzpatrick | bc9748e | 2015-02-27 19:34:56 -0800 | [diff] [blame] | 34 | if wd == wdStr { |
| 35 | return |
| 36 | } |
| 37 | if err := chdir(wdStr); err != nil { |
| 38 | return |
| 39 | } |
| 40 | } |
| 41 | |
Richard Miller | a379b7d | 2018-02-28 14:29:27 +0000 | [diff] [blame] | 42 | func fixwd(paths ...string) { |
| 43 | for _, path := range paths { |
| 44 | if path != "" && path[0] != '/' && path[0] != '#' { |
| 45 | Fixwd() |
| 46 | return |
| 47 | } |
| 48 | } |
| 49 | } |
| 50 | |
Brad Fitzpatrick | bc9748e | 2015-02-27 19:34:56 -0800 | [diff] [blame] | 51 | // goroutine-specific getwd |
| 52 | func getwd() (wd string, err error) { |
| 53 | fd, err := open(".", O_RDONLY) |
| 54 | if err != nil { |
| 55 | return "", err |
| 56 | } |
| 57 | defer Close(fd) |
| 58 | return Fd2path(fd) |
| 59 | } |
| 60 | |
| 61 | func Getwd() (wd string, err error) { |
| 62 | wdmu.Lock() |
| 63 | defer wdmu.Unlock() |
| 64 | |
| 65 | if wdSet { |
| 66 | return wdStr, nil |
| 67 | } |
| 68 | wd, err = getwd() |
| 69 | if err != nil { |
| 70 | return |
| 71 | } |
| 72 | wdSet = true |
| 73 | wdStr = wd |
| 74 | return wd, nil |
| 75 | } |
| 76 | |
| 77 | func Chdir(path string) error { |
Richard Miller | a379b7d | 2018-02-28 14:29:27 +0000 | [diff] [blame] | 78 | fixwd(path) |
Brad Fitzpatrick | bc9748e | 2015-02-27 19:34:56 -0800 | [diff] [blame] | 79 | wdmu.Lock() |
| 80 | defer wdmu.Unlock() |
| 81 | |
| 82 | if err := chdir(path); err != nil { |
| 83 | return err |
| 84 | } |
| 85 | |
| 86 | wd, err := getwd() |
| 87 | if err != nil { |
| 88 | return err |
| 89 | } |
| 90 | wdSet = true |
| 91 | wdStr = wd |
| 92 | return nil |
| 93 | } |