nvidia-container-toolkit/internal/lookup/path.go
Evan Lezar 390e5747ea Add lookup abstraction for locating executable files
Signed-off-by: Evan Lezar <elezar@nvidia.com>
2022-04-04 14:16:25 +02:00

94 lines
2.3 KiB
Go

/*
# Copyright (c) 2021, NVIDIA CORPORATION. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
*/
package lookup
import (
"fmt"
"os"
"path/filepath"
"strings"
log "github.com/sirupsen/logrus"
)
const (
envPath = "PATH"
)
var defaultPaths = []string{"/usr/local/sbin", "/usr/local/bin", "/usr/sbin", "/usr/bin", "/sbin", "/bin"}
type path struct {
file
}
// NewPathLocator creates a locator to fine executable files in the path. A logger can also be specified.
func NewPathLocator(logger *log.Logger, root string) Locator {
pathEnv := os.Getenv(envPath)
paths := filepath.SplitList(pathEnv)
if root != "" {
paths = append(paths, defaultPaths...)
}
var prefixes []string
for _, dir := range paths {
prefixes = append(prefixes, filepath.Join(root, dir))
}
l := path{
file: file{
logger: logger,
prefixes: prefixes,
filter: assertExecutable,
},
}
return &l
}
var _ Locator = (*path)(nil)
// Locate finds executable files in the path. If a relative or absolute path is specified, the prefix paths are not considered.
func (p path) Locate(filename string) ([]string, error) {
// For absolute paths we ensure that it is executable
if strings.Contains(filename, "/") {
err := assertExecutable(filename)
if err != nil {
return nil, fmt.Errorf("absolute path %v is not an executable file: %v", filename, err)
}
return []string{filename}, nil
}
return p.file.Locate(filename)
}
// assertExecutable checks whether the specified path is an execuable file.
func assertExecutable(filename string) error {
err := assertFile(filename)
if err != nil {
return err
}
info, err := os.Stat(filename)
if err != nil {
return err
}
if info.Mode()&0111 == 0 {
return fmt.Errorf("specified file '%v' is not executable", filename)
}
return nil
}