package system // import "github.com/docker/docker/pkg/system" import ( "fmt" "path/filepath" "runtime" "strings" ) const defaultUnixPathEnv = "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" // DefaultPathEnv is unix style list of directories to search for // executables. Each directory is separated from the next by a colon // ':' character . func DefaultPathEnv(os string) string { if runtime.GOOS == "windows" { if os != runtime.GOOS { return defaultUnixPathEnv } // Deliberately empty on Windows containers on Windows as the default path will be set by // the container. Docker has no context of what the default path should be. return "" } return defaultUnixPathEnv } // PathVerifier defines the subset of a PathDriver that CheckSystemDriveAndRemoveDriveLetter // actually uses in order to avoid system depending on containerd/continuity. type PathVerifier interface { IsAbs(string) bool } // CheckSystemDriveAndRemoveDriveLetter verifies that a path, if it includes a drive letter, // is the system drive. // On Linux: this is a no-op. // On Windows: this does the following> // CheckSystemDriveAndRemoveDriveLetter verifies and manipulates a Windows path. // This is used, for example, when validating a user provided path in docker cp. // If a drive letter is supplied, it must be the system drive. The drive letter // is always removed. Also, it translates it to OS semantics (IOW / to \). We // need the path in this syntax so that it can ultimately be concatenated with // a Windows long-path which doesn't support drive-letters. Examples: // C: --> Fail // C:\ --> \ // a --> a // /a --> \a // d:\ --> Fail func CheckSystemDriveAndRemoveDriveLetter(path string, driver PathVerifier) (string, error) { if runtime.GOOS != "windows" || LCOWSupported() { return path, nil } if len(path) == 2 && string(path[1]) == ":" { return "", fmt.Errorf("No relative path specified in %q", path) } if !driver.IsAbs(path) || len(path) < 2 { return filepath.FromSlash(path), nil } if string(path[1]) == ":" && !strings.EqualFold(string(path[0]), "c") { return "", fmt.Errorf("The specified path is not on the system drive (C:)") } return filepath.FromSlash(path[2:]), nil }