Adding upstream version 0.0.1.

Signed-off-by: Daniel Baumann <daniel@debian.org>

config.go

@@ -0,0 +1,846 @@
+// Package ssh_config provides tools for manipulating SSH config files.
+//
+// Importantly, this parser attempts to preserve comments in a given file, so
+// you can manipulate a `ssh_config` file from a program, if your heart desires.
+//
+// The Get() and GetStrict() functions will attempt to read values from
+// $HOME/.ssh/config, falling back to /etc/ssh/ssh_config. The first argument is
+// the host name to match on ("example.com"), and the second argument is the key
+// you want to retrieve ("Port"). The keywords are case insensitive.
+//
+//	port := ssh_config.Get("myhost", "Port")
+//
+// You can also manipulate an SSH config file and then print it or write it back
+// to disk.
+//
+//	f, _ := os.Open(filepath.Join(os.Getenv("HOME"), ".ssh", "config"))
+//	cfg, _ := ssh_config.Decode(f)
+//	for _, host := range cfg.Hosts {
+//		fmt.Println("patterns:", host.Patterns)
+//		for _, node := range host.Nodes {
+//			fmt.Println(node.String())
+//		}
+//	}
+//
+//	// Write the cfg back to disk:
+//	fmt.Println(cfg.String())
+//
+// BUG: the Match directive is currently unsupported; parsing a config with
+// a Match directive will trigger an error.
+package ssh_config
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	osuser "os/user"
+	"path/filepath"
+	"regexp"
+	"runtime"
+	"strings"
+	"sync"
+)
+
+const version = "1.2"
+
+var _ = version
+
+type configFinder func() string
+
+// UserSettings checks ~/.ssh and /etc/ssh for configuration files. The config
+// files are parsed and cached the first time Get() or GetStrict() is called.
+type UserSettings struct {
+	IgnoreErrors         bool
+	IgnoreMatchDirective bool
+	customConfig         *Config
+	customConfigFinder   configFinder
+	systemConfig         *Config
+	systemConfigFinder   configFinder
+	userConfig           *Config
+	userConfigFinder     configFinder
+	loadConfigs          sync.Once
+	onceErr              error
+}
+
+func homedir() string {
+	user, err := osuser.Current()
+	if err == nil {
+		return user.HomeDir
+	} else {
+		return os.Getenv("HOME")
+	}
+}
+
+func userConfigFinder() string {
+	return filepath.Join(homedir(), ".ssh", "config")
+}
+
+// DefaultUserSettings is the default UserSettings and is used by Get and
+// GetStrict. It checks both $HOME/.ssh/config and /etc/ssh/ssh_config for keys,
+// and it will return parse errors (if any) instead of swallowing them.
+var DefaultUserSettings = &UserSettings{
+	IgnoreErrors:         false,
+	IgnoreMatchDirective: false,
+	systemConfigFinder:   systemConfigFinder,
+	userConfigFinder:     userConfigFinder,
+}
+
+func systemConfigFinder() string {
+	return filepath.Join("/", "etc", "ssh", "ssh_config")
+}
+
+func findVal(c *Config, alias, key string) (string, error) {
+	if c == nil {
+		return "", nil
+	}
+	val, err := c.Get(alias, key)
+	if err != nil || val == "" {
+		return "", err
+	}
+	if err := validate(key, val); err != nil {
+		return "", err
+	}
+	return val, nil
+}
+
+func findAll(c *Config, alias, key string) ([]string, error) {
+	if c == nil {
+		return nil, nil
+	}
+	return c.GetAll(alias, key)
+}
+
+// Get finds the first value for key within a declaration that matches the
+// alias. Get returns the empty string if no value was found, or if IgnoreErrors
+// is false and we could not parse the configuration file. Use GetStrict to
+// disambiguate the latter cases.
+//
+// The match for key is case insensitive.
+//
+// Get is a wrapper around DefaultUserSettings.Get.
+func Get(alias, key string) string {
+	return DefaultUserSettings.Get(alias, key)
+}
+
+// GetAll retrieves zero or more directives for key for the given alias. GetAll
+// returns nil if no value was found, or if IgnoreErrors is false and we could
+// not parse the configuration file. Use GetAllStrict to disambiguate the
+// latter cases.
+//
+// In most cases you want to use Get or GetStrict, which returns a single value.
+// However, a subset of ssh configuration values (IdentityFile, for example)
+// allow you to specify multiple directives.
+//
+// The match for key is case insensitive.
+//
+// GetAll is a wrapper around DefaultUserSettings.GetAll.
+func GetAll(alias, key string) []string {
+	return DefaultUserSettings.GetAll(alias, key)
+}
+
+// GetStrict finds the first value for key within a declaration that matches the
+// alias. If key has a default value and no matching configuration is found, the
+// default will be returned. For more information on default values and the way
+// patterns are matched, see the manpage for ssh_config.
+//
+// The returned error will be non-nil if and only if a user's configuration file
+// or the system configuration file could not be parsed, and u.IgnoreErrors is
+// false.
+//
+// GetStrict is a wrapper around DefaultUserSettings.GetStrict.
+func GetStrict(alias, key string) (string, error) {
+	return DefaultUserSettings.GetStrict(alias, key)
+}
+
+// GetAllStrict retrieves zero or more directives for key for the given alias.
+//
+// In most cases you want to use Get or GetStrict, which returns a single value.
+// However, a subset of ssh configuration values (IdentityFile, for example)
+// allow you to specify multiple directives.
+//
+// The returned error will be non-nil if and only if a user's configuration file
+// or the system configuration file could not be parsed, and u.IgnoreErrors is
+// false.
+//
+// GetAllStrict is a wrapper around DefaultUserSettings.GetAllStrict.
+func GetAllStrict(alias, key string) ([]string, error) {
+	return DefaultUserSettings.GetAllStrict(alias, key)
+}
+
+// Get finds the first value for key within a declaration that matches the
+// alias. Get returns the empty string if no value was found, or if IgnoreErrors
+// is false and we could not parse the configuration file. Use GetStrict to
+// disambiguate the latter cases.
+//
+// The match for key is case insensitive.
+func (u *UserSettings) Get(alias, key string) string {
+	val, err := u.GetStrict(alias, key)
+	if err != nil {
+		return ""
+	}
+	return val
+}
+
+// GetAll retrieves zero or more directives for key for the given alias. GetAll
+// returns nil if no value was found, or if IgnoreErrors is false and we could
+// not parse the configuration file. Use GetStrict to disambiguate the latter
+// cases.
+//
+// The match for key is case insensitive.
+func (u *UserSettings) GetAll(alias, key string) []string {
+	val, _ := u.GetAllStrict(alias, key)
+	return val
+}
+
+// GetStrict finds the first value for key within a declaration that matches the
+// alias. If key has a default value and no matching configuration is found, the
+// default will be returned. For more information on default values and the way
+// patterns are matched, see the manpage for ssh_config.
+//
+// error will be non-nil if and only if a user's configuration file or the
+// system configuration file could not be parsed, and u.IgnoreErrors is false.
+func (u *UserSettings) GetStrict(alias, key string) (string, error) {
+	u.doLoadConfigs()
+	//lint:ignore S1002 I prefer it this way
+	if u.onceErr != nil && u.IgnoreErrors == false {
+		return "", u.onceErr
+	}
+	// TODO this is getting repetitive
+	if u.customConfig != nil {
+		val, err := findVal(u.customConfig, alias, key)
+		if err != nil || val != "" {
+			return val, err
+		}
+	}
+	val, err := findVal(u.userConfig, alias, key)
+	if err != nil || val != "" {
+		return val, err
+	}
+	val2, err2 := findVal(u.systemConfig, alias, key)
+	if err2 != nil || val2 != "" {
+		return val2, err2
+	}
+	return Default(key), nil
+}
+
+// GetAllStrict retrieves zero or more directives for key for the given alias.
+// If key has a default value and no matching configuration is found, the
+// default will be returned. For more information on default values and the way
+// patterns are matched, see the manpage for ssh_config.
+//
+// The returned error will be non-nil if and only if a user's configuration file
+// or the system configuration file could not be parsed, and u.IgnoreErrors is
+// false.
+func (u *UserSettings) GetAllStrict(alias, key string) ([]string, error) {
+	u.doLoadConfigs()
+	//lint:ignore S1002 I prefer it this way
+	if u.onceErr != nil && u.IgnoreErrors == false {
+		return nil, u.onceErr
+	}
+	if u.customConfig != nil {
+		val, err := findAll(u.customConfig, alias, key)
+		if err != nil || val != nil {
+			return val, err
+		}
+	}
+	val, err := findAll(u.userConfig, alias, key)
+	if err != nil || val != nil {
+		return val, err
+	}
+	val2, err2 := findAll(u.systemConfig, alias, key)
+	if err2 != nil || val2 != nil {
+		return val2, err2
+	}
+	// TODO: IdentityFile has multiple default values that we should return.
+	if def := Default(key); def != "" {
+		return []string{def}, nil
+	}
+	return []string{}, nil
+}
+
+// ConfigFinder will invoke f to try to find a ssh config file in a custom
+// location on disk, instead of in /etc/ssh or $HOME/.ssh. f should return the
+// name of a file containing SSH configuration.
+//
+// ConfigFinder must be invoked before any calls to Get or GetStrict and panics
+// if f is nil. Most users should not need to use this function.
+func (u *UserSettings) ConfigFinder(f func() string) {
+	if f == nil {
+		panic("cannot call ConfigFinder with nil function")
+	}
+	u.customConfigFinder = f
+}
+
+func (u *UserSettings) doLoadConfigs() {
+	u.loadConfigs.Do(func() {
+		var filename string
+		var err error
+		if u.customConfigFinder != nil {
+			filename = u.customConfigFinder()
+			u.customConfig, err = parseFile(filename, u.IgnoreMatchDirective)
+			// IsNotExist should be returned because a user specified this
+			// function - not existing likely means they made an error
+			// We should also respect the ignore flag
+			if err != nil && !u.IgnoreErrors {
+				u.onceErr = err
+			}
+			return
+		}
+		if u.userConfigFinder == nil {
+			filename = userConfigFinder()
+		} else {
+			filename = u.userConfigFinder()
+		}
+		u.userConfig, err = parseFile(filename, u.IgnoreMatchDirective)
+		//lint:ignore S1002 I prefer it this way
+		if err != nil && os.IsNotExist(err) == false {
+			u.onceErr = err
+			return
+		}
+		if u.systemConfigFinder == nil {
+			filename = systemConfigFinder()
+		} else {
+			filename = u.systemConfigFinder()
+		}
+		u.systemConfig, err = parseFile(filename, u.IgnoreMatchDirective)
+		//lint:ignore S1002 I prefer it this way
+		if err != nil && os.IsNotExist(err) == false {
+			u.onceErr = err
+			return
+		}
+	},
+	)
+}
+
+func parseFile(filename string, ignoreMatchDirective bool) (*Config, error) {
+	return parseWithDepth(filename, ignoreMatchDirective, 0)
+}
+
+func parseWithDepth(filename string, ignoreMatchDirective bool, depth uint8) (*Config, error) {
+	b, err := os.ReadFile(filename)
+	if err != nil {
+		return nil, err
+	}
+	return decodeBytes(b, isSystem(filename), ignoreMatchDirective, depth)
+}
+
+func isSystem(filename string) bool {
+	// TODO: not sure this is the best way to detect a system repo
+	return strings.HasPrefix(filepath.Clean(filename), "/etc/ssh")
+}
+
+// Decode reads r into a Config, or returns an error if r could not be parsed as
+// an SSH config file.
+func Decode(r io.Reader, ignoreMatchDirective bool) (*Config, error) {
+	b, err := io.ReadAll(r)
+	if err != nil {
+		return nil, err
+	}
+	return decodeBytes(b, false, ignoreMatchDirective, 0)
+}
+
+// DecodeBytes reads b into a Config, or returns an error if r could not be
+// parsed as an SSH config file.
+func DecodeBytes(b []byte, ignoreMatchDirective bool) (*Config, error) {
+	return decodeBytes(b, false, ignoreMatchDirective, 0)
+}
+
+func decodeBytes(b []byte, system, ignoreMatchDirective bool, depth uint8) (c *Config, err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			if _, ok := r.(runtime.Error); ok {
+				panic(r)
+			}
+			if e, ok := r.(error); ok && e == ErrDepthExceeded {
+				err = e
+				return
+			}
+			err = errors.New(r.(string))
+		}
+	}()
+
+	c = parseSSH(lexSSH(b), system, ignoreMatchDirective, depth)
+	return c, err
+}
+
+// Config represents an SSH config file.
+type Config struct {
+	// A list of hosts to match against. The file begins with an implicit
+	// "Host *" declaration matching all hosts.
+	Hosts                []*Host
+	depth                uint8
+	position             Position
+	ignoreMatchDirective bool
+}
+
+// Get finds the first value in the configuration that matches the alias and
+// contains key. Get returns the empty string if no value was found, or if the
+// Config contains an invalid conditional Include value.
+//
+// The match for key is case insensitive.
+func (c *Config) Get(alias, key string) (string, error) {
+	lowerKey := strings.ToLower(key)
+	for _, host := range c.Hosts {
+		if !host.Matches(alias) {
+			continue
+		}
+		for _, node := range host.Nodes {
+			switch t := node.(type) {
+			case *Empty:
+				continue
+			case *KV:
+				// "keys are case insensitive" per the spec
+				lkey := strings.ToLower(t.Key)
+				if lkey == "match" && !c.ignoreMatchDirective {
+					panic("can't handle Match directives")
+				}
+				if lkey == lowerKey {
+					return t.Value, nil
+				}
+			case *Include:
+				val := t.Get(alias, key)
+				if val != "" {
+					return val, nil
+				}
+			default:
+				return "", fmt.Errorf("unknown Node type %v", t)
+			}
+		}
+	}
+	return "", nil
+}
+
+// GetAll returns all values in the configuration that match the alias and
+// contains key, or nil if none are present.
+func (c *Config) GetAll(alias, key string) ([]string, error) {
+	lowerKey := strings.ToLower(key)
+	all := []string(nil)
+	for _, host := range c.Hosts {
+		if !host.Matches(alias) {
+			continue
+		}
+		for _, node := range host.Nodes {
+			switch t := node.(type) {
+			case *Empty:
+				continue
+			case *KV:
+				// "keys are case insensitive" per the spec
+				lkey := strings.ToLower(t.Key)
+				if lkey == "match" {
+					panic("can't handle Match directives")
+				}
+				if lkey == lowerKey {
+					all = append(all, t.Value)
+				}
+			case *Include:
+				val, _ := t.GetAll(alias, key)
+				if len(val) > 0 {
+					all = append(all, val...)
+				}
+			default:
+				return nil, fmt.Errorf("unknown Node type %v", t)
+			}
+		}
+	}
+
+	return all, nil
+}
+
+// String returns a string representation of the Config file.
+func (c Config) String() string {
+	return marshal(c).String()
+}
+
+func (c Config) MarshalText() ([]byte, error) {
+	return marshal(c).Bytes(), nil
+}
+
+func marshal(c Config) *bytes.Buffer {
+	var buf bytes.Buffer
+	for i := range c.Hosts {
+		buf.WriteString(c.Hosts[i].String())
+	}
+	return &buf
+}
+
+// Pattern is a pattern in a Host declaration. Patterns are read-only values;
+// create a new one with NewPattern().
+type Pattern struct {
+	str   string // Its appearance in the file, not the value that gets compiled.
+	regex *regexp.Regexp
+	not   bool // True if this is a negated match
+}
+
+// String prints the string representation of the pattern.
+func (p Pattern) String() string {
+	return p.str
+}
+
+// Copied from regexp.go with * and ? removed.
+var specialBytes = []byte(`\.+()|[]{}^$`)
+
+func special(b byte) bool {
+	return bytes.IndexByte(specialBytes, b) >= 0
+}
+
+// NewPattern creates a new Pattern for matching hosts. NewPattern("*") creates
+// a Pattern that matches all hosts.
+//
+// From the manpage, a pattern consists of zero or more non-whitespace
+// characters, `*' (a wildcard that matches zero or more characters), or `?' (a
+// wildcard that matches exactly one character). For example, to specify a set
+// of declarations for any host in the ".co.uk" set of domains, the following
+// pattern could be used:
+//
+//	Host *.co.uk
+//
+// The following pattern would match any host in the 192.168.0.[0-9] network range:
+//
+//	Host 192.168.0.?
+func NewPattern(s string) (*Pattern, error) {
+	if s == "" {
+		return nil, errors.New("ssh_config: empty pattern")
+	}
+	negated := false
+	if s[0] == '!' {
+		negated = true
+		s = s[1:]
+	}
+	var buf bytes.Buffer
+	buf.WriteByte('^')
+	for i := 0; i < len(s); i++ {
+		// A byte loop is correct because all metacharacters are ASCII.
+		switch b := s[i]; b {
+		case '*':
+			buf.WriteString(".*")
+		case '?':
+			buf.WriteString(".?")
+		default:
+			// borrowing from QuoteMeta here.
+			if special(b) {
+				buf.WriteByte('\\')
+			}
+			buf.WriteByte(b)
+		}
+	}
+	buf.WriteByte('$')
+	r, err := regexp.Compile(buf.String())
+	if err != nil {
+		return nil, err
+	}
+	return &Pattern{str: s, regex: r, not: negated}, nil
+}
+
+// Host describes a Host directive and the keywords that follow it.
+type Host struct {
+	// A list of host patterns that should match this host.
+	Patterns []*Pattern
+	// A Node is either a key/value pair or a comment line.
+	Nodes []Node
+	// EOLComment is the comment (if any) terminating the Host line.
+	EOLComment string
+	// Whitespace if any between the Host declaration and a trailing comment.
+	spaceBeforeComment string
+
+	hasEquals    bool
+	leadingSpace int // TODO: handle spaces vs tabs here.
+	// The file starts with an implicit "Host *" declaration.
+	implicit bool
+}
+
+// Matches returns true if the Host matches for the given alias. For
+// a description of the rules that provide a match, see the manpage for
+// ssh_config.
+func (h *Host) Matches(alias string) bool {
+	found := false
+	for i := range h.Patterns {
+		if h.Patterns[i].regex.MatchString(alias) {
+			if h.Patterns[i].not {
+				// Negated match. "A pattern entry may be negated by prefixing
+				// it with an exclamation mark (`!'). If a negated entry is
+				// matched, then the Host entry is ignored, regardless of
+				// whether any other patterns on the line match. Negated matches
+				// are therefore useful to provide exceptions for wildcard
+				// matches."
+				return false
+			}
+			found = true
+		}
+	}
+	return found
+}
+
+// String prints h as it would appear in a config file. Minor tweaks may be
+// present in the whitespace in the printed file.
+func (h *Host) String() string {
+	var buf strings.Builder
+	//lint:ignore S1002 I prefer to write it this way
+	if h.implicit == false {
+		buf.WriteString(strings.Repeat(" ", int(h.leadingSpace)))
+		buf.WriteString("Host")
+		if h.hasEquals {
+			buf.WriteString(" = ")
+		} else {
+			buf.WriteString(" ")
+		}
+		for i, pat := range h.Patterns {
+			buf.WriteString(pat.String())
+			if i < len(h.Patterns)-1 {
+				buf.WriteString(" ")
+			}
+		}
+		buf.WriteString(h.spaceBeforeComment)
+		if h.EOLComment != "" {
+			buf.WriteByte('#')
+			buf.WriteString(h.EOLComment)
+		}
+		buf.WriteByte('\n')
+	}
+	for i := range h.Nodes {
+		buf.WriteString(h.Nodes[i].String())
+		buf.WriteByte('\n')
+	}
+	return buf.String()
+}
+
+// Node represents a line in a Config.
+type Node interface {
+	Pos() Position
+	String() string
+}
+
+// KV is a line in the config file that contains a key, a value, and possibly
+// a comment.
+type KV struct {
+	Key   string
+	Value string
+	// Whitespace after the value but before any comment
+	spaceAfterValue string
+	Comment         string
+	hasEquals       bool
+	leadingSpace    int // Space before the key. TODO handle spaces vs tabs.
+	position        Position
+}
+
+// Pos returns k's Position.
+func (k *KV) Pos() Position {
+	return k.position
+}
+
+// String prints k as it was parsed in the config file.
+func (k *KV) String() string {
+	if k == nil {
+		return ""
+	}
+	equals := " "
+	if k.hasEquals {
+		equals = " = "
+	}
+	line := strings.Repeat(" ", int(k.leadingSpace)) + k.Key + equals + k.Value + k.spaceAfterValue
+	if k.Comment != "" {
+		line += "#" + k.Comment
+	}
+	return line
+}
+
+// Empty is a line in the config file that contains only whitespace or comments.
+type Empty struct {
+	Comment      string
+	leadingSpace int // TODO handle spaces vs tabs.
+	position     Position
+}
+
+// Pos returns e's Position.
+func (e *Empty) Pos() Position {
+	return e.position
+}
+
+// String prints e as it was parsed in the config file.
+func (e *Empty) String() string {
+	if e == nil {
+		return ""
+	}
+	if e.Comment == "" {
+		return ""
+	}
+	return fmt.Sprintf("%s#%s", strings.Repeat(" ", int(e.leadingSpace)), e.Comment)
+}
+
+// Include holds the result of an Include directive, including the config files
+// that have been parsed as part of that directive. At most 5 levels of Include
+// statements will be parsed.
+type Include struct {
+	// Comment is the contents of any comment at the end of the Include
+	// statement.
+	Comment string
+	// an include directive can include several different files, and wildcards
+	directives []string
+
+	mu sync.Mutex
+	// 1:1 mapping between matches and keys in files array; matches preserves
+	// ordering
+	matches []string
+	// actual filenames are listed here
+	files        map[string]*Config
+	leadingSpace int
+	position     Position
+	depth        uint8
+	hasEquals    bool
+}
+
+const maxRecurseDepth = 5
+
+// ErrDepthExceeded is returned if too many Include directives are parsed.
+// Usually this indicates a recursive loop (an Include directive pointing to the
+// file it contains).
+var ErrDepthExceeded = errors.New("ssh_config: max recurse depth exceeded")
+
+func removeDups(arr []string) []string {
+	// Use map to record duplicates as we find them.
+	encountered := make(map[string]bool, len(arr))
+	result := make([]string, 0)
+
+	for v := range arr {
+		//lint:ignore S1002 I prefer it this way
+		if encountered[arr[v]] == false {
+			encountered[arr[v]] = true
+			result = append(result, arr[v])
+		}
+	}
+	return result
+}
+
+// NewInclude creates a new Include with a list of file globs to include.
+// Configuration files are parsed greedily (e.g. as soon as this function runs).
+// Any error encountered while parsing nested configuration files will be
+// returned.
+func NewInclude(directives []string, hasEquals bool, pos Position, comment string, system, ignoreMatchDirective bool, depth uint8,
+) (*Include, error) {
+	if depth > maxRecurseDepth {
+		return nil, ErrDepthExceeded
+	}
+	inc := &Include{
+		Comment:      comment,
+		directives:   directives,
+		files:        make(map[string]*Config),
+		position:     pos,
+		leadingSpace: pos.Col - 1,
+		depth:        depth,
+		hasEquals:    hasEquals,
+	}
+	// no need for inc.mu.Lock() since nothing else can access this inc
+	matches := make([]string, 0)
+	for i := range directives {
+		var path string
+		if filepath.IsAbs(directives[i]) {
+			path = directives[i]
+		} else if system {
+			path = filepath.Join("/etc/ssh", directives[i])
+		} else {
+			path = filepath.Join(homedir(), ".ssh", directives[i])
+		}
+		theseMatches, err := filepath.Glob(path)
+		if err != nil {
+			return nil, err
+		}
+		matches = append(matches, theseMatches...)
+	}
+	matches = removeDups(matches)
+	inc.matches = matches
+	for i := range matches {
+		config, err := parseWithDepth(matches[i], ignoreMatchDirective, depth)
+		if err != nil {
+			return nil, err
+		}
+		inc.files[matches[i]] = config
+	}
+	return inc, nil
+}
+
+// Pos returns the position of the Include directive in the larger file.
+func (i *Include) Pos() Position {
+	return i.position
+}
+
+// Get finds the first value in the Include statement matching the alias and the
+// given key.
+func (inc *Include) Get(alias, key string) string {
+	inc.mu.Lock()
+	defer inc.mu.Unlock()
+	// TODO: we search files in any order which is not correct
+	for i := range inc.matches {
+		cfg := inc.files[inc.matches[i]]
+		if cfg == nil {
+			panic("nil cfg")
+		}
+		val, err := cfg.Get(alias, key)
+		if err == nil && val != "" {
+			return val
+		}
+	}
+	return ""
+}
+
+// GetAll finds all values in the Include statement matching the alias and the
+// given key.
+func (inc *Include) GetAll(alias, key string) ([]string, error) {
+	inc.mu.Lock()
+	defer inc.mu.Unlock()
+	var vals []string
+
+	// TODO: we search files in any order which is not correct
+	for i := range inc.matches {
+		cfg := inc.files[inc.matches[i]]
+		if cfg == nil {
+			panic("nil cfg")
+		}
+		val, err := cfg.GetAll(alias, key)
+		if err == nil && len(val) != 0 {
+			// In theory if SupportsMultiple was false for this key we could
+			// stop looking here. But the caller has asked us to find all
+			// instances of the keyword (and could use Get() if they wanted) so
+			// let's keep looking.
+			vals = append(vals, val...)
+		}
+	}
+	return vals, nil
+}
+
+// String prints out a string representation of this Include directive. Note
+// included Config files are not printed as part of this representation.
+func (inc *Include) String() string {
+	equals := " "
+	if inc.hasEquals {
+		equals = " = "
+	}
+	line := fmt.Sprintf("%sInclude%s%s", strings.Repeat(" ", int(inc.leadingSpace)), equals, strings.Join(inc.directives, " "))
+	if inc.Comment != "" {
+		line += " #" + inc.Comment
+	}
+	return line
+}
+
+var matchAll *Pattern
+
+func init() {
+	var err error
+	matchAll, err = NewPattern("*")
+	if err != nil {
+		panic(err)
+	}
+}
+
+func newConfig() *Config {
+	return &Config{
+		Hosts: []*Host{
+			&Host{
+				implicit: true,
+				Patterns: []*Pattern{matchAll},
+				Nodes:    make([]Node, 0),
+			},
+		},
+		depth: 0,
+	}
+}