testenv_notwin.go

     1  // Copyright 2016 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  //go:build !windows
     6  
     7  package testenv
     8  
     9  import (
    10  	"fmt"
    11  	"os"
    12  	"path/filepath"
    13  	"runtime"
    14  )
    15  
    16  func hasSymlink() (ok bool, reason string) {
    17  	switch runtime.GOOS {
    18  	case "plan9":
    19  		return false, ""
    20  	case "android", "wasip1":
    21  		// For wasip1, some runtimes forbid absolute symlinks,
    22  		// or symlinks that escape the current working directory.
    23  		// Perform a simple test to see whether the runtime
    24  		// supports symlinks or not. If we get a permission
    25  		// error, the runtime does not support symlinks.
    26  		dir, err := os.MkdirTemp("", "")
    27  		if err != nil {
    28  			return false, ""
    29  		}
    30  		defer func() {
    31  			_ = os.RemoveAll(dir)
    32  		}()
    33  		fpath := filepath.Join(dir, "testfile.txt")
    34  		if err := os.WriteFile(fpath, nil, 0644); err != nil {
    35  			return false, ""
    36  		}
    37  		if err := os.Symlink(fpath, filepath.Join(dir, "testlink")); err != nil {
    38  			if SyscallIsNotSupported(err) {
    39  				return false, fmt.Sprintf("symlinks unsupported: %s", err.Error())
    40  			}
    41  			return false, ""
    42  		}
    43  	}
    44  
    45  	return true, ""
    46  }
    47
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