Function ResolveExecutablePath

pkg/sentry/fsimpl/user/path.go:39–73

ResolveExecutablePath resolves the given executable name given the working dir and environment. Returns *ExecutableResolveError when the executable cannot be resolved.

(ctx context.Context, args *kernel.CreateProcessArgs)

// dir and environment.
// Returns *ExecutableResolveError when the executable cannot be resolved.
func ResolveExecutablePath(ctx context.Context, args *kernel.CreateProcessArgs) (string, error) {
	name := args.Filename
	if len(name) == 0 {
		if len(args.Argv) == 0 {
			return "", fmt.Errorf("no filename or command provided")
		}
		name = args.Argv[0]
	}

	// Absolute paths can be used directly.
	if path.IsAbs(name) {
		return name, nil
	}

	// Paths with '/' in them should be joined to the working directory, or
	// to the root if working directory is not set.
	if strings.IndexByte(name, '/') > 0 {
		wd := args.WorkingDirectory
		if wd == "" {
			wd = "/"
		}
		if !path.IsAbs(wd) {
			return "", fmt.Errorf("working directory %q must be absolute", wd)
		}
		return path.Join(wd, name), nil
	}

	// Otherwise, We must lookup the name in the paths.
	paths := getPath(args.Envv)
	f, err := resolve(ctx, args.Credentials, args.MountNamespace, paths, name)
	if err != nil {
		return "", &ExecutableResolveError{fmt.Errorf("error finding executable %q in PATH %v: %v", name, paths, err)}
	}
	return f, nil
}

// resolve searches for an executable in the given PATH directories.
// Error handling follows glibc execvpe() (posix/execvpe.c).