FIX: Rename path locator as executable locator

Signed-off-by: Evan Lezar <elezar@nvidia.com>

internal/lookup/executable.go

@@ -0,0 +1,93 @@
+/*
+# 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 executable struct {
+	file
+}
+
+// NewExecutaleLocator creates a locator to fine executable files in the path. A logger can also be specified.
+func NewExecutaleLocator(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 := executable{
+		file: file{
+			logger:   logger,
+			prefixes: prefixes,
+			filter:   assertExecutable,
+		},
+	}
+	return &l
+}
+
+var _ Locator = (*executable)(nil)
+
+// Locate finds executable files in the path. If a relative or absolute path is specified, the prefix paths are not considered.
+func (p executable) 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
+}