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shell2http.go
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shell2http.go
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package main
import (
"bytes"
"context"
"flag"
"fmt"
"html"
"io"
"io/ioutil"
"log"
"mime/multipart"
"net"
"net/http"
"os"
"os/exec"
"regexp"
"runtime"
"strconv"
"strings"
"time"
"github.com/mattn/go-shellwords"
"github.com/msoap/raphanus"
raphanuscommon "github.com/msoap/raphanus/common"
)
var version = "dev"
const (
// defaultPort - default port for http-server
defaultPort = 8080
// shBasicAuthVar - name of env var for basic auth credentials
shBasicAuthVar = "SH_BASIC_AUTH"
// defaultShellPOSIX - shell executable by default in POSIX systems
defaultShellPOSIX = "sh"
// defaultShellWindows - shell executable by default in Windows
defaultShellWindows = "cmd"
// defaultShellPlan9 - shell executable by default in Plan9
defaultShellPlan9 = "rc"
maxHTTPCode = 1000
maxMemoryForUploadFile = 65536
)
// indexTmpl - template for index page
const indexTmpl = `<!DOCTYPE html>
<!-- Served by shell2http/%s -->
<html>
<head>
<title>❯ shell2http</title>
<style>
body {
font-family: sans-serif;
}
li {
list-style-type: none;
}
li:before {
content: "❯";
padding-right: 5px;
}
</style>
</head>
<body>
<h1>shell2http</h1>
<ul>
%s
</ul>
Get from: <a href="https://github.com/msoap/shell2http">github.com/msoap/shell2http</a>
</body>
</html>
`
// command - one command
type command struct {
path string
cmd string
httpMethod string
handler http.HandlerFunc
}
// parsePathAndCommands - get all commands with pathes
func parsePathAndCommands(args []string) ([]command, error) {
var cmdHandlers []command
if len(args) < 2 || len(args)%2 == 1 {
return cmdHandlers, fmt.Errorf("requires a pair of path and shell command")
}
pathRe := regexp.MustCompile(`^(?:([A-Z]+):)?(/\S*)$`)
uniqPaths := map[string]bool{}
for i := 0; i < len(args); i += 2 {
path, cmd := args[i], args[i+1]
if uniqPaths[path] {
return nil, fmt.Errorf("a duplicate path was detected: %q", path)
}
pathParts := pathRe.FindStringSubmatch(path)
if len(pathParts) != 3 {
return nil, fmt.Errorf("the path %q must begin with the prefix /, and with optional METHOD: prefix", path)
}
cmdHandlers = append(cmdHandlers, command{path: pathParts[2], cmd: cmd, httpMethod: pathParts[1]})
uniqPaths[path] = true
}
return cmdHandlers, nil
}
// getShellAndParams - get default shell and command
func getShellAndParams(cmd string, appConfig Config) (shell string, params []string, err error) {
shell, params = appConfig.defaultShell, []string{appConfig.defaultShOpt, cmd} // sh -c "cmd"
// custom shell
switch {
case appConfig.shell != appConfig.defaultShell && appConfig.shell != "":
shell = appConfig.shell
case appConfig.shell == "":
cmdLine, err := shellwords.Parse(cmd)
if err != nil {
return shell, params, fmt.Errorf("failed to parse %q: %s", cmd, err)
}
shell, params = cmdLine[0], cmdLine[1:]
}
return shell, params, nil
}
// getShellHandler - get handler function for one shell command
func getShellHandler(appConfig Config, shell string, params []string, cacheTTL raphanus.DB) func(http.ResponseWriter, *http.Request) {
reStatusCode := regexp.MustCompile(`^\d+`)
return func(rw http.ResponseWriter, req *http.Request) {
shellOut, exitCode, err := execShellCommand(appConfig, shell, params, req, cacheTTL)
if err != nil {
log.Printf("out: %s, exec error: %s", string(shellOut), err)
}
customStatusCode := 0
outText := string(shellOut)
if err != nil && !appConfig.showErrors {
outText = fmt.Sprintf("%s\nexec error: %s", string(shellOut), err)
} else {
if appConfig.setCGI {
var headers map[string]string
outText, headers = parseCGIHeaders(outText)
for headerKey, headerValue := range headers {
switch headerKey {
case "Status":
statusParts := reStatusCode.FindAllString(headerValue, -1)
if len(statusParts) > 0 {
statusCode, err := strconv.Atoi(statusParts[0])
if err == nil && statusCode > 0 && statusCode < maxHTTPCode {
customStatusCode = statusCode
continue
}
}
case "Location":
customStatusCode = http.StatusFound
}
rw.Header().Set(headerKey, headerValue)
}
}
}
rw.Header().Set("X-Shell2http-Exit-Code", strconv.Itoa(exitCode))
if customStatusCode > 0 {
rw.WriteHeader(customStatusCode)
} else if exitCode > 0 && appConfig.intServerErr {
rw.WriteHeader(http.StatusInternalServerError)
}
responseWrite(rw, outText)
}
}
// execShellCommand - execute shell command, returns bytes out and error
func execShellCommand(appConfig Config, shell string, params []string, req *http.Request, cacheTTL raphanus.DB) ([]byte, int, error) {
if appConfig.cache > 0 {
if cacheData, err := cacheTTL.GetBytes(req.RequestURI); err != raphanuscommon.ErrKeyNotExists && err != nil {
log.Printf("get from cache failed: %s", err)
} else if err == nil {
// cache hit
return cacheData, 0, nil // TODO: save exit code in cache
}
}
ctx := req.Context()
if appConfig.timeout > 0 {
var cancelFn context.CancelFunc
ctx, cancelFn = context.WithTimeout(ctx, time.Duration(appConfig.timeout)*time.Second)
defer cancelFn()
}
osExecCommand := exec.CommandContext(ctx, shell, params...) // #nosec
proxySystemEnv(osExecCommand, appConfig)
finalizer := func() {}
if appConfig.setForm {
var err error
if finalizer, err = getForm(osExecCommand, req, appConfig.formCheckRe); err != nil {
log.Printf("parse form failed: %s", err)
}
}
var (
waitPipeWrite bool
pipeErrCh = make(chan error)
shellOut []byte
err error
)
if appConfig.setCGI {
setCGIEnv(osExecCommand, req, appConfig)
// get request body data data to stdin of script (if not parse form vars above)
if (req.Method == "POST" || req.Method == "PUT" || req.Method == "PATCH") && !appConfig.setForm {
if stdin, pipeErr := osExecCommand.StdinPipe(); pipeErr != nil {
log.Println("write request body data to shell failed:", pipeErr)
} else {
waitPipeWrite = true
go func() {
if _, pipeErr := io.Copy(stdin, req.Body); pipeErr != nil {
pipeErrCh <- pipeErr
return
}
pipeErrCh <- stdin.Close()
}()
}
}
}
if appConfig.includeStderr {
shellOut, err = osExecCommand.CombinedOutput()
} else {
var stderrBuf bytes.Buffer
osExecCommand.Stderr = &stderrBuf
shellOut, err = osExecCommand.Output()
if stderrBuf.Len() > 0 {
log.Printf("stderr: %s", stderrBuf.String())
}
}
if waitPipeWrite {
if pipeErr := <-pipeErrCh; pipeErr != nil {
log.Println("write request body data to shell failed:", pipeErr)
}
}
finalizer()
if appConfig.cache > 0 {
if cacheErr := cacheTTL.SetBytes(req.RequestURI, shellOut, appConfig.cache); cacheErr != nil {
log.Printf("set to cache failed: %s", cacheErr)
}
}
exitCode := osExecCommand.ProcessState.ExitCode()
return shellOut, exitCode, err
}
// setupHandlers - setup http handlers
func setupHandlers(cmdHandlers []command, appConfig Config, cacheTTL raphanus.DB) ([]command, error) {
resultHandlers := []command{}
indexLiHTML := []string{}
existsRootPath := false
// map[path][http-method]handler
groupedCmd := map[string]map[string]http.HandlerFunc{}
cmdsForLog := map[string][]string{}
for _, row := range cmdHandlers {
path, cmd := row.path, row.cmd
shell, params, err := getShellAndParams(cmd, appConfig)
if err != nil {
return nil, err
}
existsRootPath = existsRootPath || path == "/"
methodDesc := ""
if row.httpMethod != "" {
methodDesc = row.httpMethod + ": "
}
indexLiHTML = append(indexLiHTML, fmt.Sprintf(`<li><a href=".%s">%s%s</a> <span style="color: #888">- %s<span></li>`, path, methodDesc, path, html.EscapeString(cmd)))
cmdsForLog[path] = append(cmdsForLog[path], cmd)
handler := mwMethodOnly(getShellHandler(appConfig, shell, params, cacheTTL), row.httpMethod)
if _, ok := groupedCmd[path]; !ok {
groupedCmd[path] = map[string]http.HandlerFunc{}
}
groupedCmd[path][row.httpMethod] = handler
}
for path, cmds := range groupedCmd {
handler, err := mwMultiMethod(cmds)
if err != nil {
return nil, err
}
resultHandlers = append(resultHandlers, command{
path: path,
handler: handler,
cmd: strings.Join(cmdsForLog[path], "; "),
})
}
// --------------
if appConfig.addExit {
resultHandlers = append(resultHandlers, command{
path: "/exit",
cmd: "/exit",
handler: func(rw http.ResponseWriter, _ *http.Request) {
responseWrite(rw, "Bye...")
go os.Exit(0)
},
})
indexLiHTML = append(indexLiHTML, fmt.Sprintf(`<li><a href=".%s">%s</a></li>`, "/exit", "/exit"))
}
// --------------
if !appConfig.noIndex && !existsRootPath {
indexHTML := fmt.Sprintf(indexTmpl, version, strings.Join(indexLiHTML, "\n"))
resultHandlers = append(resultHandlers, command{
path: "/",
cmd: "index page",
handler: func(rw http.ResponseWriter, req *http.Request) {
if req.URL.Path != "/" {
log.Printf("%s - 404", req.URL.Path)
http.NotFound(rw, req)
return
}
responseWrite(rw, indexHTML)
},
})
}
return resultHandlers, nil
}
// responseWrite - write text to response
func responseWrite(rw io.Writer, text string) {
if _, err := io.WriteString(rw, text); err != nil {
log.Printf("print string failed: %s", err)
}
}
// setCGIEnv - set some CGI variables
func setCGIEnv(cmd *exec.Cmd, req *http.Request, appConfig Config) {
// set HTTP_* variables
for headerName, headerValue := range req.Header {
envName := strings.ToUpper(strings.Replace(headerName, "-", "_", -1))
if envName == "PROXY" {
continue
}
cmd.Env = append(cmd.Env, fmt.Sprintf("HTTP_%s=%s", envName, headerValue[0]))
}
remoteHost, remotePort, err := net.SplitHostPort(req.RemoteAddr)
if err != nil {
log.Printf("failed to parse remote address %s: %s", req.RemoteAddr, err)
}
CGIVars := [...]struct {
cgiName, value string
}{
{"PATH_INFO", req.URL.Path},
{"QUERY_STRING", req.URL.RawQuery},
{"REMOTE_ADDR", remoteHost},
{"REMOTE_PORT", remotePort},
{"REQUEST_METHOD", req.Method},
{"REQUEST_URI", req.RequestURI},
{"SCRIPT_NAME", req.URL.Path},
{"SERVER_NAME", appConfig.host},
{"SERVER_PORT", strconv.Itoa(appConfig.port)},
{"SERVER_PROTOCOL", req.Proto},
{"SERVER_SOFTWARE", "shell2http"},
}
for _, row := range CGIVars {
cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%s", row.cgiName, row.value))
}
}
/*
parse headers from script output:
Header-name1: value1\n
Header-name2: value2\n
\n
text
*/
func parseCGIHeaders(shellOut string) (string, map[string]string) {
parts := regexp.MustCompile(`\r?\n\r?\n`).Split(shellOut, 2)
if len(parts) == 2 {
headerRe := regexp.MustCompile(`^([^:\s]+):\s*(\S.*)$`)
headerLines := regexp.MustCompile(`\r?\n`).Split(parts[0], -1)
headersMap := map[string]string{}
for _, headerLine := range headerLines {
headerParts := headerRe.FindStringSubmatch(headerLine)
if len(headerParts) == 3 {
headersMap[headerParts[1]] = headerParts[2]
} else {
// headers is not valid, return all text
return shellOut, nil
}
}
return parts[1], headersMap
}
// headers don't found, return all text
return shellOut, nil
}
// getForm - parse form into environment vars, also handle uploaded files
func getForm(cmd *exec.Cmd, req *http.Request, checkFormRe *regexp.Regexp) (func(), error) {
tempDir := ""
safeFileNameRe := regexp.MustCompile(`[^\.\w\-]+`)
finalizer := func() {
if tempDir != "" {
if err := os.RemoveAll(tempDir); err != nil {
log.Println(err)
}
}
}
if err := req.ParseForm(); err != nil {
return finalizer, err
}
if isMultipartFormData(req.Header) {
if err := req.ParseMultipartForm(maxMemoryForUploadFile); err != nil {
return finalizer, err
}
}
for key, values := range req.Form {
if checkFormRe != nil {
checkedValues := []string{}
for _, v := range values {
if checkFormRe.MatchString(v) {
checkedValues = append(checkedValues, v)
}
}
values = checkedValues
}
if len(values) == 0 {
continue
}
value := strings.Join(values, ",")
cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%s", "v_"+key, value))
}
// handle uploaded files, save all to temporary files and set variables filename_XXX, filepath_XXX
if req.MultipartForm != nil {
for key, value := range req.MultipartForm.File {
if len(value) == 1 {
var (
uplFile multipart.File
outFile *os.File
err error
reqFileName = value[0].Filename
)
errCreate := errChain(func() error {
uplFile, err = value[0].Open()
return err
}, func() error {
tempDir, err = ioutil.TempDir("", "shell2http_")
return err
}, func() error {
prefix := safeFileNameRe.ReplaceAllString(reqFileName, "")
outFile, err = ioutil.TempFile(tempDir, prefix+"_")
return err
}, func() error {
_, err = io.Copy(outFile, uplFile)
return err
})
errClose := errChainAll(func() error {
if uplFile != nil {
return uplFile.Close()
}
return nil
}, func() error {
if outFile != nil {
return outFile.Close()
}
return nil
})
if errClose != nil {
return finalizer, errClose
}
if errCreate != nil {
return finalizer, errCreate
}
cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%s", "filepath_"+key, outFile.Name()))
cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%s", "filename_"+key, reqFileName))
}
}
}
return finalizer, nil
}
// isMultipartFormData - check header for multipart/form-data
func isMultipartFormData(headers http.Header) bool {
if contentType, ok := headers["Content-Type"]; ok && len(contentType) == 1 && strings.HasPrefix(contentType[0], "multipart/form-data; ") {
return true
}
return false
}
// proxySystemEnv - proxy some system vars
func proxySystemEnv(cmd *exec.Cmd, appConfig Config) {
varsNames := []string{"PATH", "HOME", "LANG", "USER", "TMPDIR"}
if runtime.GOOS == "windows" {
varsNames = append(varsNames, "USERNAME", "USERPROFILE", "HOMEDRIVE", "HOMEPATH", "TEMP", "TMP", "PATHEXT", "COMSPEC", "OS")
}
if appConfig.exportVars != "" {
varsNames = append(varsNames, strings.Split(appConfig.exportVars, ",")...)
}
for _, envRaw := range os.Environ() {
env := strings.SplitN(envRaw, "=", 2)
if env[0] != shBasicAuthVar {
if appConfig.exportAllVars {
cmd.Env = append(cmd.Env, envRaw)
} else {
for _, envVarName := range varsNames {
if strings.ToUpper(env[0]) == envVarName {
cmd.Env = append(cmd.Env, envRaw)
}
}
}
}
}
}
// errChain - handle errors on few functions
func errChain(chainFuncs ...func() error) error {
for _, fn := range chainFuncs {
if err := fn(); err != nil {
return err
}
}
return nil
}
// errChainAll - handle errors on few functions, exec all func and returns the first error
func errChainAll(chainFuncs ...func() error) error {
var resErr error
for _, fn := range chainFuncs {
if err := fn(); err != nil {
resErr = err
}
}
return resErr
}
func main() {
appConfig, err := getConfig()
if err != nil {
log.Fatal(err)
}
cmdHandlers, err := parsePathAndCommands(flag.Args())
if err != nil {
log.Fatalf("failed to parse arguments: %s", err)
}
var cacheTTL raphanus.DB
if appConfig.cache > 0 {
cacheTTL = raphanus.New()
}
cmdHandlers, err = setupHandlers(cmdHandlers, *appConfig, cacheTTL)
if err != nil {
log.Fatal(err)
}
for _, handler := range cmdHandlers {
handlerFunc := handler.handler
if len(appConfig.auth.users) > 0 {
handlerFunc = mwBasicAuth(handlerFunc, appConfig.auth)
}
if appConfig.oneThread {
handlerFunc = mwOneThread(handlerFunc)
}
handlerFunc = mwLogging(mwCommonHeaders(handlerFunc))
http.HandleFunc(handler.path, handlerFunc)
log.Printf("register: %s (%s)\n", handler.path, handler.cmd)
}
listener, err := net.Listen("tcp", net.JoinHostPort(appConfig.host, strconv.Itoa(appConfig.port)))
if err != nil {
log.Fatal(err)
}
log.Printf("listen %s\n", appConfig.readableURL(listener.Addr()))
if len(appConfig.cert) > 0 && len(appConfig.key) > 0 {
log.Fatal(http.ServeTLS(listener, nil, appConfig.cert, appConfig.key))
} else {
log.Fatal(http.Serve(listener, nil))
}
}