mirror of
https://github.com/golang/go
synced 2024-10-05 06:21:24 -06:00
a0bcaf4c00
echo back context of call in error if likely to be useful.
For example, if os.Open("/etc/passwd", os.O_RDONLY)
fails with syscall.EPERM, it returns as the os.Error
&PathError{
Op: "open",
Path: "/etc/passwd"
Error: os.EPERM
}
which formats as
open /etc/passwd: permission denied
Not converted:
datafmt
go/...
google/...
regexp
tabwriter
template
R=r
DELTA=1153 (561 added, 156 deleted, 436 changed)
OCL=30738
CL=30781
95 lines
2.1 KiB
Go
95 lines
2.1 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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package os
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import (
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"os";
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"syscall"
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)
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// Getwd returns a rooted path name corresponding to the
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// current directory. If the current directory can be
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// reached via multiple paths (due to symbolic links),
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// Getwd may return any one of them.
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func Getwd() (string, Error) {
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// If the operating system provides a Getwd call, use it.
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if syscall.ImplementsGetwd {
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s, e := syscall.Getwd();
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return s, NewSyscallError("getwd", e);
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}
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// Otherwise, we're trying to find our way back to ".".
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dot, err := Stat(".");
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if err != nil {
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return "", err;
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}
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// Clumsy but widespread kludge:
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// if $PWD is set and matches ".", use it.
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pwd, _ := Getenv("PWD");
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if len(pwd) > 0 && pwd[0] == '/' {
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d, err := Stat(pwd);
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if err == nil && d.Dev == dot.Dev && d.Ino == dot.Ino {
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return pwd, nil
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}
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}
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// Root is a special case because it has no parent
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// and ends in a slash.
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root, err := Stat("/");
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if err != nil {
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// Can't stat root - no hope.
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return "", err;
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}
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if root.Dev == dot.Dev && root.Ino == dot.Ino {
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return "/", nil
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}
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// General algorithm: find name in parent
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// and then find name of parent. Each iteration
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// adds /name to the beginning of pwd.
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elem := make([]string, 0, 16);
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pwd = "";
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for parent := "..";; parent = "../" + parent {
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if len(parent) >= 1024 { // Sanity check
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return "", ENAMETOOLONG;
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}
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fd, err := Open(parent, O_RDONLY, 0);
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if err != nil {
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return "", err;
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}
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for {
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names, err := fd.Readdirnames(100);
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if err != nil {
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fd.Close();
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return "", err;
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}
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for i, name := range names {
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d, err := Lstat(parent + "/" + name);
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if d.Dev == dot.Dev && d.Ino == dot.Ino {
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pwd = "/" + name + pwd;
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goto Found;
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}
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}
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}
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fd.Close();
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return "", ENOENT;
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Found:
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pd, err := fd.Stat();
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if err != nil {
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return "", err;
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}
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fd.Close();
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if pd.Dev == root.Dev && pd.Ino == root.Ino {
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break;
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}
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// Set up for next round.
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dot = pd;
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}
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return pwd, nil
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}
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