gvisor.dev/gvisor@v0.0.0-20240520182842-f9d4d51c7e0f/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  //go:build !false
    16  // +build !false
    17  
    18  package testutil
    19  
    20  import (
    21  	"fmt"
    22  	"os"
    23  	"path/filepath"
    24  )
    25  
    26  // FindFile searches for a file inside the test run environment. It returns the
    27  // full path to the file. It fails if none or more than one file is found.
    28  func FindFile(path string) (string, error) {
    29  	wd, err := os.Getwd()
    30  	if err != nil {
    31  		return "", err
    32  	}
    33  
    34  	// The test root is demarcated by a path element called "__main__". Search for
    35  	// it backwards from the working directory.
    36  	root := wd
    37  	for {
    38  		dir, name := filepath.Split(root)
    39  		if name == "__main__" {
    40  			break
    41  		}
    42  		if len(dir) == 0 {
    43  			return "", fmt.Errorf("directory __main__ not found in %q", wd)
    44  		}
    45  		// Remove ending slash to loop around.
    46  		root = dir[:len(dir)-1]
    47  	}
    48  
    49  	// Annoyingly, bazel adds the build type to the directory path for go
    50  	// binaries, but not for c++ binaries. We use two different patterns to
    51  	// to find our file.
    52  	patterns := []string{
    53  		// Try the obvious path first.
    54  		filepath.Join(root, path),
    55  		// If it was a go binary, use a wildcard to match the build
    56  		// type. The pattern is: /test-path/__main__/directories/*/file.
    57  		filepath.Join(root, filepath.Dir(path), "*", filepath.Base(path)),
    58  	}
    59  
    60  	for _, p := range patterns {
    61  		matches, err := filepath.Glob(p)
    62  		if err != nil {
    63  			// "The only possible returned error is ErrBadPattern,
    64  			// when pattern is malformed." -godoc
    65  			return "", fmt.Errorf("error globbing %q: %v", p, err)
    66  		}
    67  		switch len(matches) {
    68  		case 0:
    69  			// Try the next pattern.
    70  		case 1:
    71  			// We found it.
    72  			return matches[0], nil
    73  		default:
    74  			return "", fmt.Errorf("more than one match found for %q: %s", path, matches)
    75  		}
    76  	}
    77  	return "", fmt.Errorf("file %q not found", path)
    78  }