LookPath like impelementations for OS specific executable searches

Signed-off-by: Arthur Sengileyev <[email protected]>

pkg/config/config.go

@@ -579,6 +579,7 @@ type SecretConfig struct {
 // ConfigMapConfig represents the "configmap" TOML config table
 //
 // revive does not like the name because the package is already called config
+//
 //nolint:revive
 type ConfigMapConfig struct {
 	// Driver specifies the configmap driver to use.
@@ -1034,10 +1035,11 @@ func (c *Config) Capabilities(user string, addCapabilities, dropCapabilities []s
 
 // Device parses device mapping string to a src, dest & permissions string
 // Valid values for device looklike:
-//    '/dev/sdc"
-//    '/dev/sdc:/dev/xvdc"
-//    '/dev/sdc:/dev/xvdc:rwm"
-//    '/dev/sdc:rm"
+//
+//	'/dev/sdc"
+//	'/dev/sdc:/dev/xvdc"
+//	'/dev/sdc:/dev/xvdc:rwm"
+//	'/dev/sdc:rm"
 func Device(device string) (src, dst, permissions string, err error) {
 	permissions = "rwm"
 	split := strings.Split(device, ":")
@@ -1300,6 +1302,7 @@ func (c *Config) FindHelperBinary(name string, searchPATH bool) (string, error)
 		dirList = append([]string{dir}, dirList...)
 	}
 
+	expandedDirList := []string{}
 	for _, path := range dirList {
 		if path == bindirPrefix || strings.HasPrefix(path, bindirPrefix+string(filepath.Separator)) {
 			// Calculate the path to the executable first time we encounter a $BINDIR prefix.
@@ -1319,11 +1322,13 @@ func (c *Config) FindHelperBinary(name string, searchPATH bool) (string, error)
 				path = filepath.Join(bindirPath, strings.TrimPrefix(path, bindirPrefix+string(filepath.Separator)))
 			}
 		}
-		fullpath := filepath.Join(path, name)
-		if fi, err := os.Stat(fullpath); err == nil && fi.Mode().IsRegular() {
-			return fullpath, nil
-		}
+		expandedDirList = append(expandedDirList, path)
 	}
+
+	if fullpath, err := lookPathExplicit(name, expandedDirList); err == nil {
+		return fullpath, nil
+	}
+
 	if searchPATH {
 		return exec.LookPath(name)
 	}

pkg/config/lpe_unix.go

@@ -0,0 +1,56 @@
+//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || zos
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris zos
+
+package config
+
+import (
+	"errors"
+	"io/fs"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+)
+
+// ErrNotFound is the error resulting if a path search failed to find an executable file.
+var ErrNotFound = errors.New("executable file not found in $PATH")
+
+func findExecutable(file string) error {
+	d, err := os.Stat(file)
+	if err != nil {
+		return err
+	}
+	if m := d.Mode(); !m.IsDir() && m&0o111 != 0 {
+		return nil
+	}
+	return fs.ErrPermission
+}
+
+// lookPathExplicit searches for an executable named file in the
+// directories listed in dirs parameter.
+// If file contains a slash, it is tried directly and the PATH is not consulted.
+// The result may be an absolute path or a path relative to the current directory.
+func lookPathExplicit(file string, dirs []string) (string, error) {
+	// NOTE(rsc): I wish we could use the Plan 9 behavior here
+	// (only bypass the path if file begins with / or ./ or ../)
+	// but that would not match all the Unix shells.
+
+	if strings.Contains(file, "/") {
+		err := findExecutable(file)
+		if err == nil {
+			return file, nil
+		}
+		return "", &exec.Error{Name: file, Err: err}
+	}
+	for _, dir := range dirs {
+		if dir == "" {
+			// Unix shell semantics: path element "" means "."
+			dir = "."
+		}
+		path := filepath.Join(dir, file)
+		if err := findExecutable(path); err == nil {
+			return path, nil
+		}
+	}
+	return "", &exec.Error{Name: file, Err: ErrNotFound}
+}

pkg/config/lpe_windows.go

@@ -0,0 +1,90 @@
+package config
+
+import (
+	"errors"
+	"io/fs"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+)
+
+// ErrNotFound is the error resulting if a path search failed to find an executable file.
+var ErrNotFound = errors.New("executable file not found in %PATH%")
+
+func chkStat(file string) error {
+	d, err := os.Stat(file)
+	if err != nil {
+		return err
+	}
+	if d.IsDir() {
+		return fs.ErrPermission
+	}
+	return nil
+}
+
+func hasExt(file string) bool {
+	i := strings.LastIndex(file, ".")
+	if i < 0 {
+		return false
+	}
+	return strings.LastIndexAny(file, `:\/`) < i
+}
+
+func findExecutable(file string, exts []string) (string, error) {
+	if len(exts) == 0 {
+		return file, chkStat(file)
+	}
+	if hasExt(file) {
+		if chkStat(file) == nil {
+			return file, nil
+		}
+	}
+	for _, e := range exts {
+		if f := file + e; chkStat(f) == nil {
+			return f, nil
+		}
+	}
+	return "", fs.ErrNotExist
+}
+
+// lookPathExplicit searches for an executable named file in the
+// directories listed in dirs parameter.
+// If file contains a slash, it is tried directly and the PATH is not consulted.
+// LookPath also uses PATHEXT environment variable to match
+// a suitable candidate.
+// The result may be an absolute path or a path relative to the current directory.
+func lookPathExplicit(file string, dirs []string) (string, error) {
+	var exts []string
+	x := os.Getenv(`PATHEXT`)
+	if x != "" {
+		for _, e := range strings.Split(strings.ToLower(x), `;`) {
+			if e == "" {
+				continue
+			}
+			if e[0] != '.' {
+				e = "." + e
+			}
+			exts = append(exts, e)
+		}
+	} else {
+		exts = []string{".com", ".exe", ".bat", ".cmd"}
+	}
+
+	if strings.ContainsAny(file, `:\/`) {
+		if f, err := findExecutable(file, exts); err == nil {
+			return f, nil
+		} else {
+			return "", &exec.Error{Name: file, Err: err}
+		}
+	}
+	if f, err := findExecutable(filepath.Join(".", file), exts); err == nil {
+		return f, nil
+	}
+	for _, dir := range dirs {
+		if f, err := findExecutable(filepath.Join(dir, file), exts); err == nil {
+			return f, nil
+		}
+	}
+	return "", &exec.Error{Name: file, Err: ErrNotFound}
+}