ssh/config: set the default UserKnownHostsFile in setDefaults

While at it, unfold each value of IdentityFile and UserKnownHostsFile
in setDefaults, by expanding "~" into user's home directory or joining
with "config" directory if its relative.

6 files changed, 54 insertions, 13 deletions

diff --git a/lib/ssh/config/config.go b/lib/ssh/config/config.go
index 6ba14393..de5d4e34 100644
--- a/lib/ssh/config/config.go
+++ b/lib/ssh/config/config.go
@@ -9,6 +9,7 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"path/filepath"
 	"strings"
 )
 
@@ -30,6 +31,9 @@ var (
 type Config struct {
 	envs map[string]string
 
+	// dir store the path to the "config" directory.
+	dir string
+
 	// workDir store the current working directory.
 	workDir string
 
@@ -42,6 +46,12 @@ type Config struct {
 func newConfig(file string) (cfg *Config, err error) {
 	cfg = &Config{}
 
+	// If file is empty, the dir is set to ".".
+	cfg.dir, err = filepath.Abs(filepath.Dir(file))
+	if err != nil {
+		return nil, err
+	}
+
 	cfg.workDir, err = os.Getwd()
 	if err != nil {
 		return nil, err
@@ -161,8 +171,7 @@ func (cfg *Config) Get(host string) (section *Section) {
 // This function can be useful if we want to load another SSH config file
 // without using Include directive.
 func (cfg *Config) Prepend(other *Config) {
-	newSections := make([]*Section, 0,
-		len(cfg.sections)+len(other.sections))
+	newSections := make([]*Section, 0, len(cfg.sections)+len(other.sections))
 	newSections = append(newSections, other.sections...)
 	newSections = append(newSections, cfg.sections...)
 	cfg.sections = newSections
diff --git a/lib/ssh/config/parser_test.go b/lib/ssh/config/parser_test.go
index 21bef8cd..1bb6f0e1 100644
--- a/lib/ssh/config/parser_test.go
+++ b/lib/ssh/config/parser_test.go
@@ -81,6 +81,7 @@ func TestReadLines(t *testing.T) {
 			`Port 28022`,
 			`User foo`,
 			`IdentityFile ~/.ssh/foo`,
+			`UserKnownHostsFile known_hosts`,
 			`Host *foo.local`,
 			`User allfoo`,
 			`IdentityFile ~/.ssh/allfoo`,
@@ -127,6 +128,7 @@ func TestConfigParser_load(t *testing.T) {
 			`Port 28022`,
 			`User foo`,
 			`IdentityFile ~/.ssh/foo`,
+			`UserKnownHostsFile known_hosts`,
 			`Host *foo.local`,
 			`User allfoo`,
 			`IdentityFile ~/.ssh/allfoo`,
diff --git a/lib/ssh/config/section.go b/lib/ssh/config/section.go
index 6b359bf5..79158d92 100644
--- a/lib/ssh/config/section.go
+++ b/lib/ssh/config/section.go
@@ -206,6 +206,9 @@ type Section struct {
 	// name contains the raw value after Host or Match.
 	name string
 
+	// dir store the path to the "config" directory.
+	dir string
+
 	// WorkingDir contains the directory where the SSH client started.
 	// This value is required when client want to copy file from/to
 	// remote.
@@ -248,6 +251,7 @@ func NewSection(cfg *Config, name string) (section *Section) {
 	}
 
 	if cfg != nil {
+		section.dir = cfg.dir
 		section.homeDir = cfg.homeDir
 		section.WorkingDir = cfg.workDir
 	}
@@ -481,11 +485,20 @@ func (section *Section) setDefaults() {
 	if len(section.IdentityFile) == 0 {
 		section.IdentityFile = defaultIdentityFile()
 	}
+	var (
+		file string
+		x    int
+	)
+	for x, file = range section.IdentityFile {
+		section.IdentityFile[x] = section.pathUnfold(file)
+	}
 
-	for x, identFile := range section.IdentityFile {
-		if identFile[0] == '~' {
-			section.IdentityFile[x] = strings.Replace(identFile, "~", section.homeDir, 1)
-		}
+	// Set and expand the UserKnownHostsFile.
+	if len(section.knownHostsFile) == 0 {
+		section.knownHostsFile = defaultUserKnownHostsFile()
+	}
+	for x, file = range section.knownHostsFile {
+		section.knownHostsFile[x] = section.pathUnfold(file)
 	}
 
 	var (
@@ -597,9 +610,6 @@ func (section *Section) User() string {
 // UserKnownHostsFile return list of user known_hosts file set in this
 // Section.
 func (section *Section) UserKnownHostsFile() []string {
-	if len(section.knownHostsFile) == 0 {
-		return defaultUserKnownHostsFile()
-	}
 	return section.knownHostsFile
 }
 
@@ -648,7 +658,7 @@ func (section *Section) MarshalText() (text []byte, err error) {
 				buf.WriteString(`  `)
 				buf.WriteString(key)
 				buf.WriteByte(' ')
-				buf.WriteString(section.pathUnfold(val))
+				buf.WriteString(section.pathFold(val))
 				buf.WriteByte('\n')
 			}
 			continue
@@ -674,8 +684,8 @@ func (section *Section) WriteTo(w io.Writer) (n int64, err error) {
 	return int64(c), err
 }
 
-// pathUnfold replace the home directory prefix with '~'.
-func (section *Section) pathUnfold(in string) (out string) {
+// pathFold replace the home directory prefix with '~'.
+func (section *Section) pathFold(in string) (out string) {
 	if !strings.HasPrefix(in, section.homeDir) {
 		return in
 	}
@@ -683,6 +693,24 @@ func (section *Section) pathUnfold(in string) (out string) {
 	return out
 }
 
+// pathUnfold expand the file to make it absolute.
+// If the file prefixed with '~', it will expanded into home directory.
+// If the file is relative (does not start with '/'), it will expanded based
+// on the "config" directory.
+func (section *Section) pathUnfold(in string) string {
+	if len(in) == 0 {
+		return in
+	}
+	if in[0] == '/' {
+		return in
+	}
+	if in[0] == '~' {
+		return filepath.Join(section.homeDir, in[1:])
+	}
+	// The path in is relative to the "config" directory.
+	return filepath.Join(section.dir, in)
+}
+
 // setEnv set the Environments with key and value of format "KEY=VALUE".
 func (section *Section) setEnv(env string) {
 	kv := strings.SplitN(env, "=", 2)
diff --git a/lib/ssh/config/section_test.go b/lib/ssh/config/section_test.go
index e89cc7b5..f8326ec7 100644
--- a/lib/ssh/config/section_test.go
+++ b/lib/ssh/config/section_test.go
@@ -156,7 +156,7 @@ func TestSection_UserKnownHostsFile(t *testing.T) {
 	}
 
 	var listCase = []testCase{{
-		exp: defaultUserKnownHostsFile(),
+		value: ``,
 	}, {
 		value: `~/.ssh/myhost ~/.ssh/myhost2`,
 		exp: []string{
diff --git a/lib/ssh/config/testdata/config b/lib/ssh/config/testdata/config
index 2f876502..58873a35 100644
--- a/lib/ssh/config/testdata/config
+++ b/lib/ssh/config/testdata/config
@@ -15,6 +15,7 @@ Host foo.local
 	Port 28022
 	User foo
 	IdentityFile ~/.ssh/foo
+	UserKnownHostsFile known_hosts
 
 ## Override the foo.local using wildcard.
 Host *foo.local
diff --git a/lib/ssh/config/testdata/config_get_test.txt b/lib/ssh/config/testdata/config_get_test.txt
index e87444c8..fcab297b 100644
--- a/lib/ssh/config/testdata/config_get_test.txt
+++ b/lib/ssh/config/testdata/config_get_test.txt
@@ -40,6 +40,7 @@ Host foo.local
   identityfile ~/.ssh/allfoo
   port 28022
   user allfoo
+  userknownhostsfile known_hosts
   xauthlocation /usr/X11R6/bin/xauth
 
 <<< my.foo.local