func handleRRQ(res *tftp.RRQresponse) {
started := time.Now()
path := res.Request.Path
logger.Info(fmt.Sprintf(
"GET %s blocksize %d from %s",
path,
res.Request.Blocksize,
*res.Request.Addr,
))
defer res.End()
var hookResult *hooks.HookResult
for _, hook := range HOOKS {
var err error
hookResult, err = hook(res.Request.Path, *res.Request)
if err == hooks.NO_MATCH {
continue
} else if err != nil {
if err, ok := err.(*os.PathError); ok {
res.WriteError(tftp.NOT_FOUND, err.Error())
return
}
logger.Err("Failed to execute hook for '%v' error: %v", res.Request.Path, err)
res.WriteError(tftp.UNKNOWN_ERROR, "Hook failed: "+err.Error())
return
}
break
}
if hookResult == nil {
res.WriteError(tftp.NOT_FOUND, "No hook matches")
return
}
// Consume stderr in a go routine, and defer the call to hook.Finalize.
if hookResult.Stderr != nil {
stderrReady := make(chan bool)
go func() {
defer func() {
if err := hookResult.Stderr.Close(); err != nil {
logger.Err("Failed to close error reader for %s: %s", res.Request.Path, err)
}
stderrReady <- true
}()
var bytesRead int
var err error
b := make([]byte, 4096)
for ; err != io.EOF; bytesRead, err = hookResult.Stderr.Read(b) {
if bytesRead > 0 {
logger.Warning("Hook error: %s", b[:bytesRead])
}
if err != nil {
logger.Err("Error while reading error reader: %s", err)
return
}
}
}()
if hookResult.Finalize != nil {
defer func() {
<-stderrReady
err := hookResult.Finalize()
if err != nil {
logger.Err("Hook for %v failed to finalize: %v", res.Request.Path, err)
}
}()
}
}
// Close stdout before calling Finalize.
defer func() {
err := hookResult.Stdout.Close()
if err != nil {
logger.Err("Failed to close reader for %s: %s", res.Request.Path, err)
}
}()
if res.Request.TransferSize != -1 {
res.TransferSize = hookResult.Length
}
if err := res.WriteOACK(); err != nil {
logger.Err("Failed to write OACK", err)
return
}
b := make([]byte, res.Request.Blocksize)
totalBytes := 0
for {
bytesRead, err := hookResult.Stdout.Read(b)
totalBytes += bytesRead
if err == io.EOF {
if _, err := res.Write(b[:bytesRead]); err != nil {
logger.Err("Failed to write last bytes of the reader: %s", err)
return
}
break
} else if err != nil {
logger.Err("Error while reading %s: %s", hookResult.Stdout, err)
res.WriteError(tftp.UNKNOWN_ERROR, err.Error())
return
}
if _, err := res.Write(b[:bytesRead]); err != nil {
logger.Err("Failed to write bytes for %s: %s", path, err)
return
}
}
took := time.Since(started)
speed := float64(totalBytes) / took.Seconds() / 1024 / 1024
logger.Info("Sent %v bytes in %v %f MB/s\n", totalBytes, took, speed)
}
cmd := exec.Command("sh", "-c", command)
stdout, err := cmd.StdoutPipe()
if err != nil {
return nil, -1, err
}
err = cmd.Start()
// Buffering content to avoid Reader closing after cmd.Wait()
// For more informations please see:
// http://stackoverflow.com/questions/20134095/why-do-i-get-bad-file-descriptor-in-this-go-program-using-stderr-and-ioutil-re
// Note:
// This is not a perfect solution because of buffering. (Memory usage...)
// If you have better solution ...
out, err := ioutil.ReadAll(stdout)
if err != nil {
logger.Err("Shell output buffering failed: %v", err)
}
// Use goroutine to log the exit status for debugging purposes.
// XXX: It probably is bad practice to access variables from multiple
// goroutines, but I hope it is ok in this case since the purpose is
// only to read and log the status. If not we must remove this bit.
// Please let me know if you know better.
go func() {
err := cmd.Wait()
if err != nil {
logger.Err("Command '%v' failed to execute: '%v'", command, err)
}
}()
return ioutil.NopCloser(bytes.NewReader(out)), -1, err
func main() {
flag.Usage = func() {
fmt.Fprintf(os.Stderr, "\nUsage: %s [-v] [config]\n", os.Args[0])
}
verbose := flag.Bool("v", false, "a bool")
flag.Parse()
if !*verbose {
e := logger.Initialize("hooktftp")
if e != nil {
log.Fatal("Failed to initialize logger")
}
}
if len(flag.Args()) > 0 {
CONFIG_PATH = flag.Args()[0]
}
logger.Info("Reading hooks from %s", CONFIG_PATH)
configData, err := ioutil.ReadFile(CONFIG_PATH)
if err != nil {
logger.Crit("Failed to read config: %s", err)
return
}
conf, err := config.ParseYaml(configData)
if err != nil {
logger.Crit("Failed to parse config: %s", err)
return
}
for _, hookDef := range conf.HookDefs {
logger.Notice("Compiling hook %s", hookDef)
// Create new hookDef variable for the hookDef pointer for each loop
// iteration. Go reuses the hookDef variable and if we pass pointer to
// that terrible things happen.
newPointer := hookDef
hook, err := hooks.CompileHook(&newPointer)
if err != nil {
logger.Crit("Failed to compile hook %s: %s", hookDef, err)
return
}
HOOKS = append(HOOKS, hook)
}
if conf.Port == "" {
conf.Port = "69"
}
addr, err := net.ResolveUDPAddr("udp", conf.Host+":"+conf.Port)
if err != nil {
logger.Crit("Failed to resolve address: %s", err)
return
}
server, err := tftp.NewTFTPServer(addr)
if err != nil {
logger.Crit("Failed to listen: %s", err)
return
}
logger.Notice("Listening on %s:%d", conf.Host, conf.Port)
if conf.User != "" {
err := DropPrivileges(conf.User)
if err != nil {
logger.Crit("Failed to drop privileges to '%s' error: %v", conf.User, err)
return
}
currentUser, _ := user.Current()
logger.Notice("Dropped privileges to %s", currentUser)
}
if conf.User == "" && syscall.Getuid() == 0 {
logger.Warning("Running as root and 'user' is not set in %s", CONFIG_PATH)
}
for {
res, err := server.Accept()
if err != nil {
logger.Err("Bad tftp request: %s", err)
continue
}
go handleRRQ(res)
}
logger.Close()
}
func handleRRQ(res *tftp.RRQresponse) {
started := time.Now()
path := res.Request.Path
logger.Info(fmt.Sprintf(
"GET %s blocksize %d from %s",
path,
res.Request.Blocksize,
*res.Request.Addr,
))
var reader io.ReadCloser
var len int
for _, hook := range HOOKS {
var err error
reader, len, err = hook(res.Request.Path)
if err == hooks.NO_MATCH {
continue
} else if err != nil {
if err, ok := err.(*os.PathError); ok {
res.WriteError(tftp.NOT_FOUND, err.Error())
return
}
logger.Err("Failed to execute hook for '%v' error: %v", res.Request.Path, err)
res.WriteError(tftp.UNKNOWN_ERROR, "Hook failed: "+err.Error())
return
}
defer func() {
err := reader.Close()
if err != nil {
logger.Err("Failed to close reader for %s: %s", res.Request.Path, err)
}
}()
break
}
if reader == nil {
res.WriteError(tftp.NOT_FOUND, "No hook matches")
return
}
if res.Request.TransferSize != -1 {
res.TransferSize = len
}
if err := res.WriteOACK(); err != nil {
logger.Err("Failed to write OACK", err)
return
}
b := make([]byte, res.Request.Blocksize)
totalBytes := 0
for {
bytesRead, err := reader.Read(b)
totalBytes += bytesRead
if err == io.EOF {
if _, err := res.Write(b[:bytesRead]); err != nil {
logger.Err("Failed to write last bytes of the reader: %s", err)
return
}
res.End()
break
} else if err != nil {
logger.Err("Error while reading %s: %s", reader, err)
res.WriteError(tftp.UNKNOWN_ERROR, err.Error())
return
}
if _, err := res.Write(b[:bytesRead]); err != nil {
logger.Err("Failed to write bytes for %s: %s", path, err)
return
}
}
took := time.Since(started)
speed := float64(totalBytes) / took.Seconds() / 1024 / 1024
logger.Info("Sent %v bytes in %v %f MB/s\n", totalBytes, took, speed)
}