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|
package git
import (
"bufio"
"io"
"net/url"
"os"
"path/filepath"
"regexp"
"strings"
"github.com/mitchellh/go-homedir"
)
var (
sshConfigLineRE = regexp.MustCompile(`\A\s*(?P<keyword>[A-Za-z][A-Za-z0-9]*)(?:\s+|\s*=\s*)(?P<argument>.+)`)
sshTokenRE = regexp.MustCompile(`%[%h]`)
)
// SSHAliasMap encapsulates the translation of SSH hostname aliases
type SSHAliasMap map[string]string
// Translator returns a function that applies hostname aliases to URLs
func (m SSHAliasMap) Translator() func(*url.URL) *url.URL {
return func(u *url.URL) *url.URL {
if u.Scheme != "ssh" {
return u
}
resolvedHost, ok := m[u.Hostname()]
if !ok {
return u
}
if strings.EqualFold(u.Hostname(), "gitlab.com") && strings.EqualFold(resolvedHost, "ssh.gitlab.com") {
return u
}
newURL, _ := url.Parse(u.String())
newURL.Host = resolvedHost
return newURL
}
}
type sshParser struct {
homeDir string
aliasMap SSHAliasMap
hosts []string
open func(string) (io.Reader, error)
glob func(string) ([]string, error)
}
func (p *sshParser) read(fileName string) error {
var file io.Reader
if p.open == nil {
f, err := os.Open(fileName)
if err != nil {
return err
}
defer f.Close()
file = f
} else {
var err error
file, err = p.open(fileName)
if err != nil {
return err
}
}
if len(p.hosts) == 0 {
p.hosts = []string{"*"}
}
scanner := bufio.NewScanner(file)
for scanner.Scan() {
m := sshConfigLineRE.FindStringSubmatch(scanner.Text())
if len(m) < 3 {
continue
}
keyword, arguments := strings.ToLower(m[1]), m[2]
switch keyword {
case "host":
p.hosts = strings.Fields(arguments)
case "hostname":
for _, host := range p.hosts {
for _, name := range strings.Fields(arguments) {
if p.aliasMap == nil {
p.aliasMap = make(SSHAliasMap)
}
p.aliasMap[host] = sshExpandTokens(name, host)
}
}
case "include":
for _, arg := range strings.Fields(arguments) {
path := p.absolutePath(fileName, arg)
var fileNames []string
if p.glob == nil {
paths, _ := filepath.Glob(path)
for _, p := range paths {
if s, err := os.Stat(p); err == nil && !s.IsDir() {
fileNames = append(fileNames, p)
}
}
} else {
var err error
fileNames, err = p.glob(path)
if err != nil {
continue
}
}
for _, fileName := range fileNames {
_ = p.read(fileName)
}
}
}
}
return scanner.Err()
}
func (p *sshParser) absolutePath(parentFile, path string) string {
if filepath.IsAbs(path) || strings.HasPrefix(filepath.ToSlash(path), "/") {
return path
}
if strings.HasPrefix(path, "~") {
return filepath.Join(p.homeDir, strings.TrimPrefix(path, "~"))
}
if strings.HasPrefix(filepath.ToSlash(parentFile), "/etc/ssh") {
return filepath.Join("/etc/ssh", path)
}
return filepath.Join(p.homeDir, ".ssh", path)
}
// ParseSSHConfig constructs a map of SSH hostname aliases based on user and
// system configuration files
func ParseSSHConfig() SSHAliasMap {
configFiles := []string{
"/etc/ssh_config",
"/etc/ssh/ssh_config",
}
p := sshParser{}
if homeDir, err := homedir.Dir(); err == nil {
userConfig := filepath.Join(homeDir, ".ssh", "config")
configFiles = append([]string{userConfig}, configFiles...)
p.homeDir = homeDir
}
for _, file := range configFiles {
_ = p.read(file)
}
return p.aliasMap
}
func sshExpandTokens(text, host string) string {
return sshTokenRE.ReplaceAllStringFunc(text, func(match string) string {
switch match {
case "%h":
return host
case "%%":
return "%"
}
return ""
})
}
|
