github.com/SagerNet/gvisor@v0.0.0-20210707092255-7731c139d75c/pkg/test/testutil/testutil_runfiles.go (about)

     1  // Copyright 2018 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package testutil
    16  
    17  import (
    18  	"fmt"
    19  	"os"
    20  	"path/filepath"
    21  )
    22  
    23  // FindFile searchs for a file inside the test run environment. It returns the
    24  // full path to the file. It fails if none or more than one file is found.
    25  func FindFile(path string) (string, error) {
    26  	wd, err := os.Getwd()
    27  	if err != nil {
    28  		return "", err
    29  	}
    30  
    31  	// The test root is demarcated by a path element called "__main__". Search for
    32  	// it backwards from the working directory.
    33  	root := wd
    34  	for {
    35  		dir, name := filepath.Split(root)
    36  		if name == "__main__" {
    37  			break
    38  		}
    39  		if len(dir) == 0 {
    40  			return "", fmt.Errorf("directory __main__ not found in %q", wd)
    41  		}
    42  		// Remove ending slash to loop around.
    43  		root = dir[:len(dir)-1]
    44  	}
    45  
    46  	// Annoyingly, bazel adds the build type to the directory path for go
    47  	// binaries, but not for c++ binaries. We use two different patterns to
    48  	// to find our file.
    49  	patterns := []string{
    50  		// Try the obvious path first.
    51  		filepath.Join(root, path),
    52  		// If it was a go binary, use a wildcard to match the build
    53  		// type. The pattern is: /test-path/__main__/directories/*/file.
    54  		filepath.Join(root, filepath.Dir(path), "*", filepath.Base(path)),
    55  	}
    56  
    57  	for _, p := range patterns {
    58  		matches, err := filepath.Glob(p)
    59  		if err != nil {
    60  			// "The only possible returned error is ErrBadPattern,
    61  			// when pattern is malformed." -godoc
    62  			return "", fmt.Errorf("error globbing %q: %v", p, err)
    63  		}
    64  		switch len(matches) {
    65  		case 0:
    66  			// Try the next pattern.
    67  		case 1:
    68  			// We found it.
    69  			return matches[0], nil
    70  		default:
    71  			return "", fmt.Errorf("more than one match found for %q: %s", path, matches)
    72  		}
    73  	}
    74  	return "", fmt.Errorf("file %q not found", path)
    75  }