git.r.bdr.sh - rbdr/mobius/blob - hotline/transaction_handlers.go

   1 package hotline
   2
   3 import (
   4         "bytes"
   5         "encoding/binary"
   6         "errors"
   7         "fmt"
   8         "gopkg.in/yaml.v3"
   9         "math/big"
  10         "os"
  11         "path"
  12         "path/filepath"
  13         "sort"
  14         "strings"
  15         "time"
  16 )
  17
  18 type TransactionType struct {
  19         Handler        func(*ClientConn, *Transaction) ([]Transaction, error) // function for handling the transaction type
  20         Name           string                                                 // Name of transaction as it will appear in logging
  21         RequiredFields []requiredField
  22 }
  23
  24 var TransactionHandlers = map[uint16]TransactionType{
  25         // Server initiated
  26         tranChatMsg: {
  27                 Name: "tranChatMsg",
  28         },
  29         // Server initiated
  30         tranNotifyChangeUser: {
  31                 Name: "tranNotifyChangeUser",
  32         },
  33         tranError: {
  34                 Name: "tranError",
  35         },
  36         tranShowAgreement: {
  37                 Name: "tranShowAgreement",
  38         },
  39         tranUserAccess: {
  40                 Name: "tranUserAccess",
  41         },
  42         tranNotifyDeleteUser: {
  43                 Name: "tranNotifyDeleteUser",
  44         },
  45         tranAgreed: {
  46                 Name:    "tranAgreed",
  47                 Handler: HandleTranAgreed,
  48         },
  49         tranChatSend: {
  50                 Name:    "tranChatSend",
  51                 Handler: HandleChatSend,
  52                 RequiredFields: []requiredField{
  53                         {
  54                                 ID:     fieldData,
  55                                 minLen: 0,
  56                         },
  57                 },
  58         },
  59         tranDelNewsArt: {
  60                 Name:    "tranDelNewsArt",
  61                 Handler: HandleDelNewsArt,
  62         },
  63         tranDelNewsItem: {
  64                 Name:    "tranDelNewsItem",
  65                 Handler: HandleDelNewsItem,
  66         },
  67         tranDeleteFile: {
  68                 Name:    "tranDeleteFile",
  69                 Handler: HandleDeleteFile,
  70         },
  71         tranDeleteUser: {
  72                 Name:    "tranDeleteUser",
  73                 Handler: HandleDeleteUser,
  74         },
  75         tranDisconnectUser: {
  76                 Name:    "tranDisconnectUser",
  77                 Handler: HandleDisconnectUser,
  78         },
  79         tranDownloadFile: {
  80                 Name:    "tranDownloadFile",
  81                 Handler: HandleDownloadFile,
  82         },
  83         tranDownloadFldr: {
  84                 Name:    "tranDownloadFldr",
  85                 Handler: HandleDownloadFolder,
  86         },
  87         tranGetClientInfoText: {
  88                 Name:    "tranGetClientInfoText",
  89                 Handler: HandleGetClientInfoText,
  90         },
  91         tranGetFileInfo: {
  92                 Name:    "tranGetFileInfo",
  93                 Handler: HandleGetFileInfo,
  94         },
  95         tranGetFileNameList: {
  96                 Name:    "tranGetFileNameList",
  97                 Handler: HandleGetFileNameList,
  98         },
  99         tranGetMsgs: {
 100                 Name:    "tranGetMsgs",
 101                 Handler: HandleGetMsgs,
 102         },
 103         tranGetNewsArtData: {
 104                 Name:    "tranGetNewsArtData",
 105                 Handler: HandleGetNewsArtData,
 106         },
 107         tranGetNewsArtNameList: {
 108                 Name:    "tranGetNewsArtNameList",
 109                 Handler: HandleGetNewsArtNameList,
 110         },
 111         tranGetNewsCatNameList: {
 112                 Name:    "tranGetNewsCatNameList",
 113                 Handler: HandleGetNewsCatNameList,
 114         },
 115         tranGetUser: {
 116                 Name:    "tranGetUser",
 117                 Handler: HandleGetUser,
 118         },
 119         tranGetUserNameList: {
 120                 Name:    "tranHandleGetUserNameList",
 121                 Handler: HandleGetUserNameList,
 122         },
 123         tranInviteNewChat: {
 124                 Name:    "tranInviteNewChat",
 125                 Handler: HandleInviteNewChat,
 126         },
 127         tranInviteToChat: {
 128                 Name:    "tranInviteToChat",
 129                 Handler: HandleInviteToChat,
 130         },
 131         tranJoinChat: {
 132                 Name:    "tranJoinChat",
 133                 Handler: HandleJoinChat,
 134         },
 135         tranKeepAlive: {
 136                 Name:    "tranKeepAlive",
 137                 Handler: HandleKeepAlive,
 138         },
 139         tranLeaveChat: {
 140                 Name:    "tranJoinChat",
 141                 Handler: HandleLeaveChat,
 142         },
 143         tranListUsers: {
 144                 Name:    "tranListUsers",
 145                 Handler: HandleListUsers,
 146         },
 147         tranMoveFile: {
 148                 Name:    "tranMoveFile",
 149                 Handler: HandleMoveFile,
 150         },
 151         tranNewFolder: {
 152                 Name:    "tranNewFolder",
 153                 Handler: HandleNewFolder,
 154         },
 155         tranNewNewsCat: {
 156                 Name:    "tranNewNewsCat",
 157                 Handler: HandleNewNewsCat,
 158         },
 159         tranNewNewsFldr: {
 160                 Name:    "tranNewNewsFldr",
 161                 Handler: HandleNewNewsFldr,
 162         },
 163         tranNewUser: {
 164                 Name:    "tranNewUser",
 165                 Handler: HandleNewUser,
 166         },
 167         tranUpdateUser: {
 168                 Name:    "tranUpdateUser",
 169                 Handler: HandleUpdateUser,
 170         },
 171         tranOldPostNews: {
 172                 Name:    "tranOldPostNews",
 173                 Handler: HandleTranOldPostNews,
 174         },
 175         tranPostNewsArt: {
 176                 Name:    "tranPostNewsArt",
 177                 Handler: HandlePostNewsArt,
 178         },
 179         tranRejectChatInvite: {
 180                 Name:    "tranRejectChatInvite",
 181                 Handler: HandleRejectChatInvite,
 182         },
 183         tranSendInstantMsg: {
 184                 Name:    "tranSendInstantMsg",
 185                 Handler: HandleSendInstantMsg,
 186                 RequiredFields: []requiredField{
 187                         {
 188                                 ID:     fieldData,
 189                                 minLen: 0,
 190                         },
 191                         {
 192                                 ID: fieldUserID,
 193                         },
 194                 },
 195         },
 196         tranSetChatSubject: {
 197                 Name:    "tranSetChatSubject",
 198                 Handler: HandleSetChatSubject,
 199         },
 200         tranMakeFileAlias: {
 201                 Name:    "tranMakeFileAlias",
 202                 Handler: HandleMakeAlias,
 203                 RequiredFields: []requiredField{
 204                         {ID: fieldFileName, minLen: 1},
 205                         {ID: fieldFilePath, minLen: 1},
 206                         {ID: fieldFileNewPath, minLen: 1},
 207                 },
 208         },
 209         tranSetClientUserInfo: {
 210                 Name:    "tranSetClientUserInfo",
 211                 Handler: HandleSetClientUserInfo,
 212         },
 213         tranSetFileInfo: {
 214                 Name:    "tranSetFileInfo",
 215                 Handler: HandleSetFileInfo,
 216         },
 217         tranSetUser: {
 218                 Name:    "tranSetUser",
 219                 Handler: HandleSetUser,
 220         },
 221         tranUploadFile: {
 222                 Name:    "tranUploadFile",
 223                 Handler: HandleUploadFile,
 224         },
 225         tranUploadFldr: {
 226                 Name:    "tranUploadFldr",
 227                 Handler: HandleUploadFolder,
 228         },
 229         tranUserBroadcast: {
 230                 Name:    "tranUserBroadcast",
 231                 Handler: HandleUserBroadcast,
 232         },
 233         tranDownloadBanner: {
 234                 Name:    "tranDownloadBanner",
 235                 Handler: HandleDownloadBanner,
 236         },
 237 }
 238
 239 func HandleChatSend(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 240         if !cc.Authorize(accessSendChat) {
 241                 res = append(res, cc.NewErrReply(t, "You are not allowed to participate in chat."))
 242                 return res, err
 243         }
 244
 245         // Truncate long usernames
 246         trunc := fmt.Sprintf("%13s", cc.UserName)
 247         formattedMsg := fmt.Sprintf("\r%.14s:  %s", trunc, t.GetField(fieldData).Data)
 248
 249         // By holding the option key, Hotline chat allows users to send /me formatted messages like:
 250         // *** Halcyon does stuff
 251         // This is indicated by the presence of the optional field fieldChatOptions set to a value of 1.
 252         // Most clients do not send this option for normal chat messages.
 253         if t.GetField(fieldChatOptions).Data != nil && bytes.Equal(t.GetField(fieldChatOptions).Data, []byte{0, 1}) {
 254                 formattedMsg = fmt.Sprintf("\r*** %s %s", cc.UserName, t.GetField(fieldData).Data)
 255         }
 256
 257         // The ChatID field is used to identify messages as belonging to a private chat.
 258         // All clients *except* Frogblast omit this field for public chat, but Frogblast sends a value of 00 00 00 00.
 259         chatID := t.GetField(fieldChatID).Data
 260         if chatID != nil && !bytes.Equal([]byte{0, 0, 0, 0}, chatID) {
 261                 chatInt := binary.BigEndian.Uint32(chatID)
 262                 privChat := cc.Server.PrivateChats[chatInt]
 263
 264                 clients := sortedClients(privChat.ClientConn)
 265
 266                 // send the message to all connected clients of the private chat
 267                 for _, c := range clients {
 268                         res = append(res, *NewTransaction(
 269                                 tranChatMsg,
 270                                 c.ID,
 271                                 NewField(fieldChatID, chatID),
 272                                 NewField(fieldData, []byte(formattedMsg)),
 273                         ))
 274                 }
 275                 return res, err
 276         }
 277
 278         for _, c := range sortedClients(cc.Server.Clients) {
 279                 // Filter out clients that do not have the read chat permission
 280                 if c.Authorize(accessReadChat) {
 281                         res = append(res, *NewTransaction(tranChatMsg, c.ID, NewField(fieldData, []byte(formattedMsg))))
 282                 }
 283         }
 284
 285         return res, err
 286 }
 287
 288 // HandleSendInstantMsg sends instant message to the user on the current server.
 289 // Fields used in the request:
 290 //
 291 //      103     User ID
 292 //      113     Options
 293 //              One of the following values:
 294 //              - User message (myOpt_UserMessage = 1)
 295 //              - Refuse message (myOpt_RefuseMessage = 2)
 296 //              - Refuse chat (myOpt_RefuseChat  = 3)
 297 //              - Automatic response (myOpt_AutomaticResponse = 4)"
 298 //      101     Data    Optional
 299 //      214     Quoting message Optional
 300 //
 301 // Fields used in the reply:
 302 // None
 303 func HandleSendInstantMsg(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 304         if !cc.Authorize(accessSendPrivMsg) {
 305                 res = append(res, cc.NewErrReply(t, "You are not allowed to send private messages."))
 306                 return res, err
 307         }
 308
 309         msg := t.GetField(fieldData)
 310         ID := t.GetField(fieldUserID)
 311
 312         reply := NewTransaction(
 313                 tranServerMsg,
 314                 &ID.Data,
 315                 NewField(fieldData, msg.Data),
 316                 NewField(fieldUserName, cc.UserName),
 317                 NewField(fieldUserID, *cc.ID),
 318                 NewField(fieldOptions, []byte{0, 1}),
 319         )
 320
 321         // Later versions of Hotline include the original message in the fieldQuotingMsg field so
 322         //  the receiving client can display both the received message and what it is in reply to
 323         if t.GetField(fieldQuotingMsg).Data != nil {
 324                 reply.Fields = append(reply.Fields, NewField(fieldQuotingMsg, t.GetField(fieldQuotingMsg).Data))
 325         }
 326
 327         id, _ := byteToInt(ID.Data)
 328         otherClient, ok := cc.Server.Clients[uint16(id)]
 329         if !ok {
 330                 return res, errors.New("invalid client ID")
 331         }
 332
 333         // Check if target user has "Refuse private messages" flag
 334         flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(otherClient.Flags)))
 335         if flagBitmap.Bit(userFLagRefusePChat) == 1 {
 336                 res = append(res,
 337                         *NewTransaction(
 338                                 tranServerMsg,
 339                                 cc.ID,
 340                                 NewField(fieldData, []byte(string(otherClient.UserName)+" does not accept private messages.")),
 341                                 NewField(fieldUserName, otherClient.UserName),
 342                                 NewField(fieldUserID, *otherClient.ID),
 343                                 NewField(fieldOptions, []byte{0, 2}),
 344                         ),
 345                 )
 346         } else {
 347                 res = append(res, *reply)
 348         }
 349
 350         // Respond with auto reply if other client has it enabled
 351         if len(otherClient.AutoReply) > 0 {
 352                 res = append(res,
 353                         *NewTransaction(
 354                                 tranServerMsg,
 355                                 cc.ID,
 356                                 NewField(fieldData, otherClient.AutoReply),
 357                                 NewField(fieldUserName, otherClient.UserName),
 358                                 NewField(fieldUserID, *otherClient.ID),
 359                                 NewField(fieldOptions, []byte{0, 1}),
 360                         ),
 361                 )
 362         }
 363
 364         res = append(res, cc.NewReply(t))
 365
 366         return res, err
 367 }
 368
 369 func HandleGetFileInfo(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 370         fileName := t.GetField(fieldFileName).Data
 371         filePath := t.GetField(fieldFilePath).Data
 372
 373         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
 374         if err != nil {
 375                 return res, err
 376         }
 377
 378         fw, err := newFileWrapper(cc.Server.FS, fullFilePath, 0)
 379         if err != nil {
 380                 return res, err
 381         }
 382
 383         res = append(res, cc.NewReply(t,
 384                 NewField(fieldFileName, []byte(fw.name)),
 385                 NewField(fieldFileTypeString, fw.ffo.FlatFileInformationFork.friendlyType()),
 386                 NewField(fieldFileCreatorString, fw.ffo.FlatFileInformationFork.friendlyCreator()),
 387                 NewField(fieldFileComment, fw.ffo.FlatFileInformationFork.Comment),
 388                 NewField(fieldFileType, fw.ffo.FlatFileInformationFork.TypeSignature),
 389                 NewField(fieldFileCreateDate, fw.ffo.FlatFileInformationFork.CreateDate),
 390                 NewField(fieldFileModifyDate, fw.ffo.FlatFileInformationFork.ModifyDate),
 391                 NewField(fieldFileSize, fw.totalSize()),
 392         ))
 393         return res, err
 394 }
 395
 396 // HandleSetFileInfo updates a file or folder name and/or comment from the Get Info window
 397 // Fields used in the request:
 398 // * 201        File name
 399 // * 202        File path       Optional
 400 // * 211        File new name   Optional
 401 // * 210        File comment    Optional
 402 // Fields used in the reply:    None
 403 func HandleSetFileInfo(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 404         fileName := t.GetField(fieldFileName).Data
 405         filePath := t.GetField(fieldFilePath).Data
 406
 407         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
 408         if err != nil {
 409                 return res, err
 410         }
 411
 412         fi, err := cc.Server.FS.Stat(fullFilePath)
 413         if err != nil {
 414                 return res, err
 415         }
 416
 417         hlFile, err := newFileWrapper(cc.Server.FS, fullFilePath, 0)
 418         if err != nil {
 419                 return res, err
 420         }
 421         if t.GetField(fieldFileComment).Data != nil {
 422                 switch mode := fi.Mode(); {
 423                 case mode.IsDir():
 424                         if !cc.Authorize(accessSetFolderComment) {
 425                                 res = append(res, cc.NewErrReply(t, "You are not allowed to set comments for folders."))
 426                                 return res, err
 427                         }
 428                 case mode.IsRegular():
 429                         if !cc.Authorize(accessSetFileComment) {
 430                                 res = append(res, cc.NewErrReply(t, "You are not allowed to set comments for files."))
 431                                 return res, err
 432                         }
 433                 }
 434
 435                 if err := hlFile.ffo.FlatFileInformationFork.setComment(t.GetField(fieldFileComment).Data); err != nil {
 436                         return res, err
 437                 }
 438                 w, err := hlFile.infoForkWriter()
 439                 if err != nil {
 440                         return res, err
 441                 }
 442                 _, err = w.Write(hlFile.ffo.FlatFileInformationFork.MarshalBinary())
 443                 if err != nil {
 444                         return res, err
 445                 }
 446         }
 447
 448         fullNewFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, t.GetField(fieldFileNewName).Data)
 449         if err != nil {
 450                 return nil, err
 451         }
 452
 453         fileNewName := t.GetField(fieldFileNewName).Data
 454
 455         if fileNewName != nil {
 456                 switch mode := fi.Mode(); {
 457                 case mode.IsDir():
 458                         if !cc.Authorize(accessRenameFolder) {
 459                                 res = append(res, cc.NewErrReply(t, "You are not allowed to rename folders."))
 460                                 return res, err
 461                         }
 462                         err = os.Rename(fullFilePath, fullNewFilePath)
 463                         if os.IsNotExist(err) {
 464                                 res = append(res, cc.NewErrReply(t, "Cannot rename folder "+string(fileName)+" because it does not exist or cannot be found."))
 465                                 return res, err
 466                         }
 467                 case mode.IsRegular():
 468                         if !cc.Authorize(accessRenameFile) {
 469                                 res = append(res, cc.NewErrReply(t, "You are not allowed to rename files."))
 470                                 return res, err
 471                         }
 472                         fileDir, err := readPath(cc.Server.Config.FileRoot, filePath, []byte{})
 473                         if err != nil {
 474                                 return nil, err
 475                         }
 476                         hlFile.name = string(fileNewName)
 477                         err = hlFile.move(fileDir)
 478                         if os.IsNotExist(err) {
 479                                 res = append(res, cc.NewErrReply(t, "Cannot rename file "+string(fileName)+" because it does not exist or cannot be found."))
 480                                 return res, err
 481                         }
 482                         if err != nil {
 483                                 return res, err
 484                         }
 485                 }
 486         }
 487
 488         res = append(res, cc.NewReply(t))
 489         return res, err
 490 }
 491
 492 // HandleDeleteFile deletes a file or folder
 493 // Fields used in the request:
 494 // * 201        File name
 495 // * 202        File path
 496 // Fields used in the reply: none
 497 func HandleDeleteFile(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 498         fileName := t.GetField(fieldFileName).Data
 499         filePath := t.GetField(fieldFilePath).Data
 500
 501         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
 502         if err != nil {
 503                 return res, err
 504         }
 505
 506         hlFile, err := newFileWrapper(cc.Server.FS, fullFilePath, 0)
 507         if err != nil {
 508                 return res, err
 509         }
 510
 511         fi, err := hlFile.dataFile()
 512         if err != nil {
 513                 res = append(res, cc.NewErrReply(t, "Cannot delete file "+string(fileName)+" because it does not exist or cannot be found."))
 514                 return res, nil
 515         }
 516
 517         switch mode := fi.Mode(); {
 518         case mode.IsDir():
 519                 if !cc.Authorize(accessDeleteFolder) {
 520                         res = append(res, cc.NewErrReply(t, "You are not allowed to delete folders."))
 521                         return res, err
 522                 }
 523         case mode.IsRegular():
 524                 if !cc.Authorize(accessDeleteFile) {
 525                         res = append(res, cc.NewErrReply(t, "You are not allowed to delete files."))
 526                         return res, err
 527                 }
 528         }
 529
 530         if err := hlFile.delete(); err != nil {
 531                 return res, err
 532         }
 533
 534         res = append(res, cc.NewReply(t))
 535         return res, err
 536 }
 537
 538 // HandleMoveFile moves files or folders. Note: seemingly not documented
 539 func HandleMoveFile(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 540         fileName := string(t.GetField(fieldFileName).Data)
 541
 542         filePath, err := readPath(cc.Server.Config.FileRoot, t.GetField(fieldFilePath).Data, t.GetField(fieldFileName).Data)
 543         if err != nil {
 544                 return res, err
 545         }
 546
 547         fileNewPath, err := readPath(cc.Server.Config.FileRoot, t.GetField(fieldFileNewPath).Data, nil)
 548         if err != nil {
 549                 return res, err
 550         }
 551
 552         cc.logger.Infow("Move file", "src", filePath+"/"+fileName, "dst", fileNewPath+"/"+fileName)
 553
 554         hlFile, err := newFileWrapper(cc.Server.FS, filePath, 0)
 555         if err != nil {
 556                 return res, err
 557         }
 558
 559         fi, err := hlFile.dataFile()
 560         if err != nil {
 561                 res = append(res, cc.NewErrReply(t, "Cannot delete file "+fileName+" because it does not exist or cannot be found."))
 562                 return res, err
 563         }
 564         if err != nil {
 565                 return res, err
 566         }
 567         switch mode := fi.Mode(); {
 568         case mode.IsDir():
 569                 if !cc.Authorize(accessMoveFolder) {
 570                         res = append(res, cc.NewErrReply(t, "You are not allowed to move folders."))
 571                         return res, err
 572                 }
 573         case mode.IsRegular():
 574                 if !cc.Authorize(accessMoveFile) {
 575                         res = append(res, cc.NewErrReply(t, "You are not allowed to move files."))
 576                         return res, err
 577                 }
 578         }
 579         if err := hlFile.move(fileNewPath); err != nil {
 580                 return res, err
 581         }
 582         // TODO: handle other possible errors; e.g. fileWrapper delete fails due to fileWrapper permission issue
 583
 584         res = append(res, cc.NewReply(t))
 585         return res, err
 586 }
 587
 588 func HandleNewFolder(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 589         if !cc.Authorize(accessCreateFolder) {
 590                 res = append(res, cc.NewErrReply(t, "You are not allowed to create folders."))
 591                 return res, err
 592         }
 593         folderName := string(t.GetField(fieldFileName).Data)
 594
 595         folderName = path.Join("/", folderName)
 596
 597         var subPath string
 598
 599         // fieldFilePath is only present for nested paths
 600         if t.GetField(fieldFilePath).Data != nil {
 601                 var newFp FilePath
 602                 _, err := newFp.Write(t.GetField(fieldFilePath).Data)
 603                 if err != nil {
 604                         return nil, err
 605                 }
 606
 607                 for _, pathItem := range newFp.Items {
 608                         subPath = filepath.Join("/", subPath, string(pathItem.Name))
 609                 }
 610         }
 611         newFolderPath := path.Join(cc.Server.Config.FileRoot, subPath, folderName)
 612
 613         // TODO: check path and folder name lengths
 614
 615         if _, err := cc.Server.FS.Stat(newFolderPath); !os.IsNotExist(err) {
 616                 msg := fmt.Sprintf("Cannot create folder \"%s\" because there is already a file or folder with that name.", folderName)
 617                 return []Transaction{cc.NewErrReply(t, msg)}, nil
 618         }
 619
 620         // TODO: check for disallowed characters to maintain compatibility for original client
 621
 622         if err := cc.Server.FS.Mkdir(newFolderPath, 0777); err != nil {
 623                 msg := fmt.Sprintf("Cannot create folder \"%s\" because an error occurred.", folderName)
 624                 return []Transaction{cc.NewErrReply(t, msg)}, nil
 625         }
 626
 627         res = append(res, cc.NewReply(t))
 628         return res, err
 629 }
 630
 631 func HandleSetUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 632         if !cc.Authorize(accessModifyUser) {
 633                 res = append(res, cc.NewErrReply(t, "You are not allowed to modify accounts."))
 634                 return res, err
 635         }
 636
 637         login := DecodeUserString(t.GetField(fieldUserLogin).Data)
 638         userName := string(t.GetField(fieldUserName).Data)
 639
 640         newAccessLvl := t.GetField(fieldUserAccess).Data
 641
 642         account := cc.Server.Accounts[login]
 643         account.Name = userName
 644         copy(account.Access[:], newAccessLvl)
 645
 646         // If the password field is cleared in the Hotline edit user UI, the SetUser transaction does
 647         // not include fieldUserPassword
 648         if t.GetField(fieldUserPassword).Data == nil {
 649                 account.Password = hashAndSalt([]byte(""))
 650         }
 651         if len(t.GetField(fieldUserPassword).Data) > 1 {
 652                 account.Password = hashAndSalt(t.GetField(fieldUserPassword).Data)
 653         }
 654
 655         out, err := yaml.Marshal(&account)
 656         if err != nil {
 657                 return res, err
 658         }
 659         if err := os.WriteFile(filepath.Join(cc.Server.ConfigDir, "Users", login+".yaml"), out, 0666); err != nil {
 660                 return res, err
 661         }
 662
 663         // Notify connected clients logged in as the user of the new access level
 664         for _, c := range cc.Server.Clients {
 665                 if c.Account.Login == login {
 666                         // Note: comment out these two lines to test server-side deny messages
 667                         newT := NewTransaction(tranUserAccess, c.ID, NewField(fieldUserAccess, newAccessLvl))
 668                         res = append(res, *newT)
 669
 670                         flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(c.Flags)))
 671                         if c.Authorize(accessDisconUser) {
 672                                 flagBitmap.SetBit(flagBitmap, userFlagAdmin, 1)
 673                         } else {
 674                                 flagBitmap.SetBit(flagBitmap, userFlagAdmin, 0)
 675                         }
 676                         binary.BigEndian.PutUint16(c.Flags, uint16(flagBitmap.Int64()))
 677
 678                         c.Account.Access = account.Access
 679
 680                         cc.sendAll(
 681                                 tranNotifyChangeUser,
 682                                 NewField(fieldUserID, *c.ID),
 683                                 NewField(fieldUserFlags, c.Flags),
 684                                 NewField(fieldUserName, c.UserName),
 685                                 NewField(fieldUserIconID, c.Icon),
 686                         )
 687                 }
 688         }
 689
 690         res = append(res, cc.NewReply(t))
 691         return res, err
 692 }
 693
 694 func HandleGetUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 695         if !cc.Authorize(accessOpenUser) {
 696                 res = append(res, cc.NewErrReply(t, "You are not allowed to view accounts."))
 697                 return res, err
 698         }
 699
 700         account := cc.Server.Accounts[string(t.GetField(fieldUserLogin).Data)]
 701         if account == nil {
 702                 res = append(res, cc.NewErrReply(t, "Account does not exist."))
 703                 return res, err
 704         }
 705
 706         res = append(res, cc.NewReply(t,
 707                 NewField(fieldUserName, []byte(account.Name)),
 708                 NewField(fieldUserLogin, negateString(t.GetField(fieldUserLogin).Data)),
 709                 NewField(fieldUserPassword, []byte(account.Password)),
 710                 NewField(fieldUserAccess, account.Access[:]),
 711         ))
 712         return res, err
 713 }
 714
 715 func HandleListUsers(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 716         if !cc.Authorize(accessOpenUser) {
 717                 res = append(res, cc.NewErrReply(t, "You are not allowed to view accounts."))
 718                 return res, err
 719         }
 720
 721         var userFields []Field
 722         for _, acc := range cc.Server.Accounts {
 723                 b := make([]byte, 0, 100)
 724                 n, err := acc.Read(b)
 725                 if err != nil {
 726                         return res, err
 727                 }
 728
 729                 userFields = append(userFields, NewField(fieldData, b[:n]))
 730         }
 731
 732         res = append(res, cc.NewReply(t, userFields...))
 733         return res, err
 734 }
 735
 736 // HandleUpdateUser is used by the v1.5+ multi-user editor to perform account editing for multiple users at a time.
 737 // An update can be a mix of these actions:
 738 // * Create user
 739 // * Delete user
 740 // * Modify user (including renaming the account login)
 741 //
 742 // The Transaction sent by the client includes one data field per user that was modified.  This data field in turn
 743 // contains another data field encoded in its payload with a varying number of sub fields depending on which action is
 744 // performed.  This seems to be the only place in the Hotline protocol where a data field contains another data field.
 745 func HandleUpdateUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 746         for _, field := range t.Fields {
 747                 subFields, err := ReadFields(field.Data[0:2], field.Data[2:])
 748                 if err != nil {
 749                         return res, err
 750                 }
 751
 752                 if len(subFields) == 1 {
 753                         login := DecodeUserString(getField(fieldData, &subFields).Data)
 754                         cc.logger.Infow("DeleteUser", "login", login)
 755
 756                         if !cc.Authorize(accessDeleteUser) {
 757                                 res = append(res, cc.NewErrReply(t, "You are not allowed to delete accounts."))
 758                                 return res, err
 759                         }
 760
 761                         if err := cc.Server.DeleteUser(login); err != nil {
 762                                 return res, err
 763                         }
 764                         continue
 765                 }
 766
 767                 login := DecodeUserString(getField(fieldUserLogin, &subFields).Data)
 768
 769                 // check if the login dataFile; if so, we know we are updating an existing user
 770                 if acc, ok := cc.Server.Accounts[login]; ok {
 771                         cc.logger.Infow("UpdateUser", "login", login)
 772
 773                         // account dataFile, so this is an update action
 774                         if !cc.Authorize(accessModifyUser) {
 775                                 res = append(res, cc.NewErrReply(t, "You are not allowed to modify accounts."))
 776                                 return res, err
 777                         }
 778
 779                         if getField(fieldUserPassword, &subFields) != nil {
 780                                 newPass := getField(fieldUserPassword, &subFields).Data
 781                                 acc.Password = hashAndSalt(newPass)
 782                         } else {
 783                                 acc.Password = hashAndSalt([]byte(""))
 784                         }
 785
 786                         if getField(fieldUserAccess, &subFields) != nil {
 787                                 copy(acc.Access[:], getField(fieldUserAccess, &subFields).Data)
 788                         }
 789
 790                         err = cc.Server.UpdateUser(
 791                                 DecodeUserString(getField(fieldData, &subFields).Data),
 792                                 DecodeUserString(getField(fieldUserLogin, &subFields).Data),
 793                                 string(getField(fieldUserName, &subFields).Data),
 794                                 acc.Password,
 795                                 acc.Access,
 796                         )
 797                         if err != nil {
 798                                 return res, err
 799                         }
 800                 } else {
 801                         cc.logger.Infow("CreateUser", "login", login)
 802
 803                         if !cc.Authorize(accessCreateUser) {
 804                                 res = append(res, cc.NewErrReply(t, "You are not allowed to create new accounts."))
 805                                 return res, err
 806                         }
 807
 808                         newAccess := accessBitmap{}
 809                         copy(newAccess[:], getField(fieldUserAccess, &subFields).Data[:])
 810
 811                         // Prevent account from creating new account with greater permission
 812                         for i := 0; i < 64; i++ {
 813                                 if newAccess.IsSet(i) {
 814                                         if !cc.Authorize(i) {
 815                                                 return append(res, cc.NewErrReply(t, "Cannot create account with more access than yourself.")), err
 816                                         }
 817                                 }
 818                         }
 819
 820                         err := cc.Server.NewUser(login, string(getField(fieldUserName, &subFields).Data), string(getField(fieldUserPassword, &subFields).Data), newAccess)
 821                         if err != nil {
 822                                 return []Transaction{}, err
 823                         }
 824                 }
 825         }
 826
 827         res = append(res, cc.NewReply(t))
 828         return res, err
 829 }
 830
 831 // HandleNewUser creates a new user account
 832 func HandleNewUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 833         if !cc.Authorize(accessCreateUser) {
 834                 res = append(res, cc.NewErrReply(t, "You are not allowed to create new accounts."))
 835                 return res, err
 836         }
 837
 838         login := DecodeUserString(t.GetField(fieldUserLogin).Data)
 839
 840         // If the account already dataFile, reply with an error
 841         if _, ok := cc.Server.Accounts[login]; ok {
 842                 res = append(res, cc.NewErrReply(t, "Cannot create account "+login+" because there is already an account with that login."))
 843                 return res, err
 844         }
 845
 846         newAccess := accessBitmap{}
 847         copy(newAccess[:], t.GetField(fieldUserAccess).Data[:])
 848
 849         // Prevent account from creating new account with greater permission
 850         for i := 0; i < 64; i++ {
 851                 if newAccess.IsSet(i) {
 852                         if !cc.Authorize(i) {
 853                                 res = append(res, cc.NewErrReply(t, "Cannot create account with more access than yourself."))
 854                                 return res, err
 855                         }
 856                 }
 857         }
 858
 859         if err := cc.Server.NewUser(login, string(t.GetField(fieldUserName).Data), string(t.GetField(fieldUserPassword).Data), newAccess); err != nil {
 860                 return []Transaction{}, err
 861         }
 862
 863         res = append(res, cc.NewReply(t))
 864         return res, err
 865 }
 866
 867 func HandleDeleteUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 868         if !cc.Authorize(accessDeleteUser) {
 869                 res = append(res, cc.NewErrReply(t, "You are not allowed to delete accounts."))
 870                 return res, err
 871         }
 872
 873         // TODO: Handle case where account doesn't exist; e.g. delete race condition
 874         login := DecodeUserString(t.GetField(fieldUserLogin).Data)
 875
 876         if err := cc.Server.DeleteUser(login); err != nil {
 877                 return res, err
 878         }
 879
 880         res = append(res, cc.NewReply(t))
 881         return res, err
 882 }
 883
 884 // HandleUserBroadcast sends an Administrator Message to all connected clients of the server
 885 func HandleUserBroadcast(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 886         if !cc.Authorize(accessBroadcast) {
 887                 res = append(res, cc.NewErrReply(t, "You are not allowed to send broadcast messages."))
 888                 return res, err
 889         }
 890
 891         cc.sendAll(
 892                 tranServerMsg,
 893                 NewField(fieldData, t.GetField(tranGetMsgs).Data),
 894                 NewField(fieldChatOptions, []byte{0}),
 895         )
 896
 897         res = append(res, cc.NewReply(t))
 898         return res, err
 899 }
 900
 901 // HandleGetClientInfoText returns user information for the specific user.
 902 //
 903 // Fields used in the request:
 904 // 103  User ID
 905 //
 906 // Fields used in the reply:
 907 // 102  User name
 908 // 101  Data            User info text string
 909 func HandleGetClientInfoText(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 910         if !cc.Authorize(accessGetClientInfo) {
 911                 res = append(res, cc.NewErrReply(t, "You are not allowed to get client info."))
 912                 return res, err
 913         }
 914
 915         clientID, _ := byteToInt(t.GetField(fieldUserID).Data)
 916
 917         clientConn := cc.Server.Clients[uint16(clientID)]
 918         if clientConn == nil {
 919                 return append(res, cc.NewErrReply(t, "User not found.")), err
 920         }
 921
 922         res = append(res, cc.NewReply(t,
 923                 NewField(fieldData, []byte(clientConn.String())),
 924                 NewField(fieldUserName, clientConn.UserName),
 925         ))
 926         return res, err
 927 }
 928
 929 func HandleGetUserNameList(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 930         res = append(res, cc.NewReply(t, cc.Server.connectedUsers()...))
 931
 932         return res, err
 933 }
 934
 935 func HandleTranAgreed(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 936         cc.Agreed = true
 937
 938         if t.GetField(fieldUserName).Data != nil {
 939                 if cc.Authorize(accessAnyName) {
 940                         cc.UserName = t.GetField(fieldUserName).Data
 941                 } else {
 942                         cc.UserName = []byte(cc.Account.Name)
 943                 }
 944         }
 945
 946         cc.Icon = t.GetField(fieldUserIconID).Data
 947
 948         cc.logger = cc.logger.With("name", string(cc.UserName))
 949         cc.logger.Infow("Login successful", "clientVersion", fmt.Sprintf("%v", func() int { i, _ := byteToInt(cc.Version); return i }()))
 950
 951         options := t.GetField(fieldOptions).Data
 952         optBitmap := big.NewInt(int64(binary.BigEndian.Uint16(options)))
 953
 954         flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(cc.Flags)))
 955
 956         // Check refuse private PM option
 957         if optBitmap.Bit(refusePM) == 1 {
 958                 flagBitmap.SetBit(flagBitmap, userFlagRefusePM, 1)
 959                 binary.BigEndian.PutUint16(cc.Flags, uint16(flagBitmap.Int64()))
 960         }
 961
 962         // Check refuse private chat option
 963         if optBitmap.Bit(refuseChat) == 1 {
 964                 flagBitmap.SetBit(flagBitmap, userFLagRefusePChat, 1)
 965                 binary.BigEndian.PutUint16(cc.Flags, uint16(flagBitmap.Int64()))
 966         }
 967
 968         // Check auto response
 969         if optBitmap.Bit(autoResponse) == 1 {
 970                 cc.AutoReply = t.GetField(fieldAutomaticResponse).Data
 971         } else {
 972                 cc.AutoReply = []byte{}
 973         }
 974
 975         trans := cc.notifyOthers(
 976                 *NewTransaction(
 977                         tranNotifyChangeUser, nil,
 978                         NewField(fieldUserName, cc.UserName),
 979                         NewField(fieldUserID, *cc.ID),
 980                         NewField(fieldUserIconID, cc.Icon),
 981                         NewField(fieldUserFlags, cc.Flags),
 982                 ),
 983         )
 984         res = append(res, trans...)
 985
 986         if cc.Server.Config.BannerFile != "" {
 987                 res = append(res, *NewTransaction(tranServerBanner, cc.ID, NewField(fieldBannerType, []byte("JPEG"))))
 988         }
 989
 990         res = append(res, cc.NewReply(t))
 991
 992         return res, err
 993 }
 994
 995 const defaultNewsDateFormat = "Jan02 15:04" // Jun23 20:49
 996 //  "Mon, 02 Jan 2006 15:04:05 MST"
 997
 998 const defaultNewsTemplate = `From %s (%s):
 999
1000 %s
1001
1002 __________________________________________________________`
1003
1004 // HandleTranOldPostNews updates the flat news
1005 // Fields used in this request:
1006 // 101  Data
1007 func HandleTranOldPostNews(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1008         if !cc.Authorize(accessNewsPostArt) {
1009                 res = append(res, cc.NewErrReply(t, "You are not allowed to post news."))
1010                 return res, err
1011         }
1012
1013         cc.Server.flatNewsMux.Lock()
1014         defer cc.Server.flatNewsMux.Unlock()
1015
1016         newsDateTemplate := defaultNewsDateFormat
1017         if cc.Server.Config.NewsDateFormat != "" {
1018                 newsDateTemplate = cc.Server.Config.NewsDateFormat
1019         }
1020
1021         newsTemplate := defaultNewsTemplate
1022         if cc.Server.Config.NewsDelimiter != "" {
1023                 newsTemplate = cc.Server.Config.NewsDelimiter
1024         }
1025
1026         newsPost := fmt.Sprintf(newsTemplate+"\r", cc.UserName, time.Now().Format(newsDateTemplate), t.GetField(fieldData).Data)
1027         newsPost = strings.Replace(newsPost, "\n", "\r", -1)
1028
1029         // update news in memory
1030         cc.Server.FlatNews = append([]byte(newsPost), cc.Server.FlatNews...)
1031
1032         // update news on disk
1033         if err := cc.Server.FS.WriteFile(filepath.Join(cc.Server.ConfigDir, "MessageBoard.txt"), cc.Server.FlatNews, 0644); err != nil {
1034                 return res, err
1035         }
1036
1037         // Notify all clients of updated news
1038         cc.sendAll(
1039                 tranNewMsg,
1040                 NewField(fieldData, []byte(newsPost)),
1041         )
1042
1043         res = append(res, cc.NewReply(t))
1044         return res, err
1045 }
1046
1047 func HandleDisconnectUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1048         if !cc.Authorize(accessDisconUser) {
1049                 res = append(res, cc.NewErrReply(t, "You are not allowed to disconnect users."))
1050                 return res, err
1051         }
1052
1053         clientConn := cc.Server.Clients[binary.BigEndian.Uint16(t.GetField(fieldUserID).Data)]
1054
1055         if clientConn.Authorize(accessCannotBeDiscon) {
1056                 res = append(res, cc.NewErrReply(t, clientConn.Account.Login+" is not allowed to be disconnected."))
1057                 return res, err
1058         }
1059
1060         // If fieldOptions is set, then the client IP is banned in addition to disconnected.
1061         // 00 01 = temporary ban
1062         // 00 02 = permanent ban
1063         if t.GetField(fieldOptions).Data != nil {
1064                 switch t.GetField(fieldOptions).Data[1] {
1065                 case 1:
1066                         // send message: "You are temporarily banned on this server"
1067                         cc.logger.Infow("Disconnect & temporarily ban " + string(clientConn.UserName))
1068
1069                         res = append(res, *NewTransaction(
1070                                 tranServerMsg,
1071                                 clientConn.ID,
1072                                 NewField(fieldData, []byte("You are temporarily banned on this server")),
1073                                 NewField(fieldChatOptions, []byte{0, 0}),
1074                         ))
1075
1076                         banUntil := time.Now().Add(tempBanDuration)
1077                         cc.Server.banList[strings.Split(clientConn.RemoteAddr, ":")[0]] = &banUntil
1078                         cc.Server.writeBanList()
1079                 case 2:
1080                         // send message: "You are permanently banned on this server"
1081                         cc.logger.Infow("Disconnect & ban " + string(clientConn.UserName))
1082
1083                         res = append(res, *NewTransaction(
1084                                 tranServerMsg,
1085                                 clientConn.ID,
1086                                 NewField(fieldData, []byte("You are permanently banned on this server")),
1087                                 NewField(fieldChatOptions, []byte{0, 0}),
1088                         ))
1089
1090                         cc.Server.banList[strings.Split(clientConn.RemoteAddr, ":")[0]] = nil
1091                         cc.Server.writeBanList()
1092                 }
1093         }
1094
1095         // TODO: remove this awful hack
1096         go func() {
1097                 time.Sleep(1 * time.Second)
1098                 clientConn.Disconnect()
1099         }()
1100
1101         return append(res, cc.NewReply(t)), err
1102 }
1103
1104 // HandleGetNewsCatNameList returns a list of news categories for a path
1105 // Fields used in the request:
1106 // 325  News path       (Optional)
1107 func HandleGetNewsCatNameList(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1108         if !cc.Authorize(accessNewsReadArt) {
1109                 res = append(res, cc.NewErrReply(t, "You are not allowed to read news."))
1110                 return res, err
1111         }
1112
1113         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1114         cats := cc.Server.GetNewsCatByPath(pathStrs)
1115
1116         // To store the keys in slice in sorted order
1117         keys := make([]string, len(cats))
1118         i := 0
1119         for k := range cats {
1120                 keys[i] = k
1121                 i++
1122         }
1123         sort.Strings(keys)
1124
1125         var fieldData []Field
1126         for _, k := range keys {
1127                 cat := cats[k]
1128                 b, _ := cat.MarshalBinary()
1129                 fieldData = append(fieldData, NewField(
1130                         fieldNewsCatListData15,
1131                         b,
1132                 ))
1133         }
1134
1135         res = append(res, cc.NewReply(t, fieldData...))
1136         return res, err
1137 }
1138
1139 func HandleNewNewsCat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1140         if !cc.Authorize(accessNewsCreateCat) {
1141                 res = append(res, cc.NewErrReply(t, "You are not allowed to create news categories."))
1142                 return res, err
1143         }
1144
1145         name := string(t.GetField(fieldNewsCatName).Data)
1146         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1147
1148         cats := cc.Server.GetNewsCatByPath(pathStrs)
1149         cats[name] = NewsCategoryListData15{
1150                 Name:     name,
1151                 Type:     []byte{0, 3},
1152                 Articles: map[uint32]*NewsArtData{},
1153                 SubCats:  make(map[string]NewsCategoryListData15),
1154         }
1155
1156         if err := cc.Server.writeThreadedNews(); err != nil {
1157                 return res, err
1158         }
1159         res = append(res, cc.NewReply(t))
1160         return res, err
1161 }
1162
1163 // Fields used in the request:
1164 // 322  News category name
1165 // 325  News path
1166 func HandleNewNewsFldr(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1167         if !cc.Authorize(accessNewsCreateFldr) {
1168                 res = append(res, cc.NewErrReply(t, "You are not allowed to create news folders."))
1169                 return res, err
1170         }
1171
1172         name := string(t.GetField(fieldFileName).Data)
1173         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1174
1175         cc.logger.Infof("Creating new news folder %s", name)
1176
1177         cats := cc.Server.GetNewsCatByPath(pathStrs)
1178         cats[name] = NewsCategoryListData15{
1179                 Name:     name,
1180                 Type:     []byte{0, 2},
1181                 Articles: map[uint32]*NewsArtData{},
1182                 SubCats:  make(map[string]NewsCategoryListData15),
1183         }
1184         if err := cc.Server.writeThreadedNews(); err != nil {
1185                 return res, err
1186         }
1187         res = append(res, cc.NewReply(t))
1188         return res, err
1189 }
1190
1191 // HandleGetNewsArtData gets the list of article names at the specified news path.
1192
1193 // Fields used in the request:
1194 // 325  News path       Optional
1195
1196 // Fields used in the reply:
1197 // 321  News article list data  Optional
1198 func HandleGetNewsArtNameList(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1199         if !cc.Authorize(accessNewsReadArt) {
1200                 res = append(res, cc.NewErrReply(t, "You are not allowed to read news."))
1201                 return res, err
1202         }
1203         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1204
1205         var cat NewsCategoryListData15
1206         cats := cc.Server.ThreadedNews.Categories
1207
1208         for _, fp := range pathStrs {
1209                 cat = cats[fp]
1210                 cats = cats[fp].SubCats
1211         }
1212
1213         nald := cat.GetNewsArtListData()
1214
1215         res = append(res, cc.NewReply(t, NewField(fieldNewsArtListData, nald.Payload())))
1216         return res, err
1217 }
1218
1219 // HandleGetNewsArtData requests information about the specific news article.
1220 // Fields used in the request:
1221 //
1222 // Request fields
1223 // 325  News path
1224 // 326  News article ID
1225 // 327  News article data flavor
1226 //
1227 // Fields used in the reply:
1228 // 328  News article title
1229 // 329  News article poster
1230 // 330  News article date
1231 // 331  Previous article ID
1232 // 332  Next article ID
1233 // 335  Parent article ID
1234 // 336  First child article ID
1235 // 327  News article data flavor        "Should be “text/plain”
1236 // 333  News article data       Optional (if data flavor is “text/plain”)
1237 func HandleGetNewsArtData(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1238         if !cc.Authorize(accessNewsReadArt) {
1239                 res = append(res, cc.NewErrReply(t, "You are not allowed to read news."))
1240                 return res, err
1241         }
1242
1243         var cat NewsCategoryListData15
1244         cats := cc.Server.ThreadedNews.Categories
1245
1246         for _, fp := range ReadNewsPath(t.GetField(fieldNewsPath).Data) {
1247                 cat = cats[fp]
1248                 cats = cats[fp].SubCats
1249         }
1250
1251         // The official Hotline clients will send the article ID as 2 bytes if possible, but
1252         // some third party clients such as Frogblast and Heildrun will always send 4 bytes
1253         convertedID, err := byteToInt(t.GetField(fieldNewsArtID).Data)
1254         if err != nil {
1255                 return res, err
1256         }
1257
1258         art := cat.Articles[uint32(convertedID)]
1259         if art == nil {
1260                 res = append(res, cc.NewReply(t))
1261                 return res, err
1262         }
1263
1264         res = append(res, cc.NewReply(t,
1265                 NewField(fieldNewsArtTitle, []byte(art.Title)),
1266                 NewField(fieldNewsArtPoster, []byte(art.Poster)),
1267                 NewField(fieldNewsArtDate, art.Date),
1268                 NewField(fieldNewsArtPrevArt, art.PrevArt),
1269                 NewField(fieldNewsArtNextArt, art.NextArt),
1270                 NewField(fieldNewsArtParentArt, art.ParentArt),
1271                 NewField(fieldNewsArt1stChildArt, art.FirstChildArt),
1272                 NewField(fieldNewsArtDataFlav, []byte("text/plain")),
1273                 NewField(fieldNewsArtData, []byte(art.Data)),
1274         ))
1275         return res, err
1276 }
1277
1278 // HandleDelNewsItem deletes an existing threaded news folder or category from the server.
1279 // Fields used in the request:
1280 // 325  News path
1281 // Fields used in the reply:
1282 // None
1283 func HandleDelNewsItem(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1284         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1285
1286         cats := cc.Server.ThreadedNews.Categories
1287         delName := pathStrs[len(pathStrs)-1]
1288         if len(pathStrs) > 1 {
1289                 for _, fp := range pathStrs[0 : len(pathStrs)-1] {
1290                         cats = cats[fp].SubCats
1291                 }
1292         }
1293
1294         if bytes.Equal(cats[delName].Type, []byte{0, 3}) {
1295                 if !cc.Authorize(accessNewsDeleteCat) {
1296                         return append(res, cc.NewErrReply(t, "You are not allowed to delete news categories.")), nil
1297                 }
1298         } else {
1299                 if !cc.Authorize(accessNewsDeleteFldr) {
1300                         return append(res, cc.NewErrReply(t, "You are not allowed to delete news folders.")), nil
1301                 }
1302         }
1303
1304         delete(cats, delName)
1305
1306         if err := cc.Server.writeThreadedNews(); err != nil {
1307                 return res, err
1308         }
1309
1310         return append(res, cc.NewReply(t)), nil
1311 }
1312
1313 func HandleDelNewsArt(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1314         if !cc.Authorize(accessNewsDeleteArt) {
1315                 res = append(res, cc.NewErrReply(t, "You are not allowed to delete news articles."))
1316                 return res, err
1317         }
1318
1319         // Request Fields
1320         // 325  News path
1321         // 326  News article ID
1322         // 337  News article – recursive delete       Delete child articles (1) or not (0)
1323         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1324         ID, err := byteToInt(t.GetField(fieldNewsArtID).Data)
1325         if err != nil {
1326                 return res, err
1327         }
1328
1329         // TODO: Delete recursive
1330         cats := cc.Server.GetNewsCatByPath(pathStrs[:len(pathStrs)-1])
1331
1332         catName := pathStrs[len(pathStrs)-1]
1333         cat := cats[catName]
1334
1335         delete(cat.Articles, uint32(ID))
1336
1337         cats[catName] = cat
1338         if err := cc.Server.writeThreadedNews(); err != nil {
1339                 return res, err
1340         }
1341
1342         res = append(res, cc.NewReply(t))
1343         return res, err
1344 }
1345
1346 // Request fields
1347 // 325  News path
1348 // 326  News article ID                                                 ID of the parent article?
1349 // 328  News article title
1350 // 334  News article flags
1351 // 327  News article data flavor                Currently “text/plain”
1352 // 333  News article data
1353 func HandlePostNewsArt(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1354         if !cc.Authorize(accessNewsPostArt) {
1355                 res = append(res, cc.NewErrReply(t, "You are not allowed to post news articles."))
1356                 return res, err
1357         }
1358
1359         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1360         cats := cc.Server.GetNewsCatByPath(pathStrs[:len(pathStrs)-1])
1361
1362         catName := pathStrs[len(pathStrs)-1]
1363         cat := cats[catName]
1364
1365         artID, err := byteToInt(t.GetField(fieldNewsArtID).Data)
1366         if err != nil {
1367                 return res, err
1368         }
1369         convertedArtID := uint32(artID)
1370         bs := make([]byte, 4)
1371         binary.LittleEndian.PutUint32(bs, convertedArtID)
1372
1373         newArt := NewsArtData{
1374                 Title:         string(t.GetField(fieldNewsArtTitle).Data),
1375                 Poster:        string(cc.UserName),
1376                 Date:          toHotlineTime(time.Now()),
1377                 PrevArt:       []byte{0, 0, 0, 0},
1378                 NextArt:       []byte{0, 0, 0, 0},
1379                 ParentArt:     bs,
1380                 FirstChildArt: []byte{0, 0, 0, 0},
1381                 DataFlav:      []byte("text/plain"),
1382                 Data:          string(t.GetField(fieldNewsArtData).Data),
1383         }
1384
1385         var keys []int
1386         for k := range cat.Articles {
1387                 keys = append(keys, int(k))
1388         }
1389
1390         nextID := uint32(1)
1391         if len(keys) > 0 {
1392                 sort.Ints(keys)
1393                 prevID := uint32(keys[len(keys)-1])
1394                 nextID = prevID + 1
1395
1396                 binary.BigEndian.PutUint32(newArt.PrevArt, prevID)
1397
1398                 // Set next article ID
1399                 binary.BigEndian.PutUint32(cat.Articles[prevID].NextArt, nextID)
1400         }
1401
1402         // Update parent article with first child reply
1403         parentID := convertedArtID
1404         if parentID != 0 {
1405                 parentArt := cat.Articles[parentID]
1406
1407                 if bytes.Equal(parentArt.FirstChildArt, []byte{0, 0, 0, 0}) {
1408                         binary.BigEndian.PutUint32(parentArt.FirstChildArt, nextID)
1409                 }
1410         }
1411
1412         cat.Articles[nextID] = &newArt
1413
1414         cats[catName] = cat
1415         if err := cc.Server.writeThreadedNews(); err != nil {
1416                 return res, err
1417         }
1418
1419         res = append(res, cc.NewReply(t))
1420         return res, err
1421 }
1422
1423 // HandleGetMsgs returns the flat news data
1424 func HandleGetMsgs(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1425         if !cc.Authorize(accessNewsReadArt) {
1426                 res = append(res, cc.NewErrReply(t, "You are not allowed to read news."))
1427                 return res, err
1428         }
1429
1430         res = append(res, cc.NewReply(t, NewField(fieldData, cc.Server.FlatNews)))
1431
1432         return res, err
1433 }
1434
1435 func HandleDownloadFile(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1436         if !cc.Authorize(accessDownloadFile) {
1437                 res = append(res, cc.NewErrReply(t, "You are not allowed to download files."))
1438                 return res, err
1439         }
1440
1441         fileName := t.GetField(fieldFileName).Data
1442         filePath := t.GetField(fieldFilePath).Data
1443         resumeData := t.GetField(fieldFileResumeData).Data
1444
1445         var dataOffset int64
1446         var frd FileResumeData
1447         if resumeData != nil {
1448                 if err := frd.UnmarshalBinary(t.GetField(fieldFileResumeData).Data); err != nil {
1449                         return res, err
1450                 }
1451                 // TODO: handle rsrc fork offset
1452                 dataOffset = int64(binary.BigEndian.Uint32(frd.ForkInfoList[0].DataSize[:]))
1453         }
1454
1455         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
1456         if err != nil {
1457                 return res, err
1458         }
1459
1460         hlFile, err := newFileWrapper(cc.Server.FS, fullFilePath, dataOffset)
1461         if err != nil {
1462                 return res, err
1463         }
1464
1465         xferSize := hlFile.ffo.TransferSize(0)
1466
1467         ft := cc.newFileTransfer(FileDownload, fileName, filePath, xferSize)
1468
1469         // TODO: refactor to remove this
1470         if resumeData != nil {
1471                 var frd FileResumeData
1472                 if err := frd.UnmarshalBinary(t.GetField(fieldFileResumeData).Data); err != nil {
1473                         return res, err
1474                 }
1475                 ft.fileResumeData = &frd
1476         }
1477
1478         // Optional field for when a HL v1.5+ client requests file preview
1479         // Used only for TEXT, JPEG, GIFF, BMP or PICT files
1480         // The value will always be 2
1481         if t.GetField(fieldFileTransferOptions).Data != nil {
1482                 ft.options = t.GetField(fieldFileTransferOptions).Data
1483                 xferSize = hlFile.ffo.FlatFileDataForkHeader.DataSize[:]
1484         }
1485
1486         res = append(res, cc.NewReply(t,
1487                 NewField(fieldRefNum, ft.refNum[:]),
1488                 NewField(fieldWaitingCount, []byte{0x00, 0x00}), // TODO: Implement waiting count
1489                 NewField(fieldTransferSize, xferSize),
1490                 NewField(fieldFileSize, hlFile.ffo.FlatFileDataForkHeader.DataSize[:]),
1491         ))
1492
1493         return res, err
1494 }
1495
1496 // Download all files from the specified folder and sub-folders
1497 func HandleDownloadFolder(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1498         if !cc.Authorize(accessDownloadFile) {
1499                 res = append(res, cc.NewErrReply(t, "You are not allowed to download folders."))
1500                 return res, err
1501         }
1502
1503         fullFilePath, err := readPath(cc.Server.Config.FileRoot, t.GetField(fieldFilePath).Data, t.GetField(fieldFileName).Data)
1504         if err != nil {
1505                 return res, err
1506         }
1507
1508         transferSize, err := CalcTotalSize(fullFilePath)
1509         if err != nil {
1510                 return res, err
1511         }
1512         itemCount, err := CalcItemCount(fullFilePath)
1513         if err != nil {
1514                 return res, err
1515         }
1516
1517         fileTransfer := cc.newFileTransfer(FolderDownload, t.GetField(fieldFileName).Data, t.GetField(fieldFilePath).Data, transferSize)
1518
1519         var fp FilePath
1520         _, err = fp.Write(t.GetField(fieldFilePath).Data)
1521         if err != nil {
1522                 return res, err
1523         }
1524
1525         res = append(res, cc.NewReply(t,
1526                 NewField(fieldRefNum, fileTransfer.ReferenceNumber),
1527                 NewField(fieldTransferSize, transferSize),
1528                 NewField(fieldFolderItemCount, itemCount),
1529                 NewField(fieldWaitingCount, []byte{0x00, 0x00}), // TODO: Implement waiting count
1530         ))
1531         return res, err
1532 }
1533
1534 // Upload all files from the local folder and its subfolders to the specified path on the server
1535 // Fields used in the request
1536 // 201  File name
1537 // 202  File path
1538 // 108  transfer size   Total size of all items in the folder
1539 // 220  Folder item count
1540 // 204  File transfer options   "Optional Currently set to 1" (TODO: ??)
1541 func HandleUploadFolder(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1542         var fp FilePath
1543         if t.GetField(fieldFilePath).Data != nil {
1544                 if _, err = fp.Write(t.GetField(fieldFilePath).Data); err != nil {
1545                         return res, err
1546                 }
1547         }
1548
1549         // Handle special cases for Upload and Drop Box folders
1550         if !cc.Authorize(accessUploadAnywhere) {
1551                 if !fp.IsUploadDir() && !fp.IsDropbox() {
1552                         res = append(res, cc.NewErrReply(t, fmt.Sprintf("Cannot accept upload of the folder \"%v\" because you are only allowed to upload to the \"Uploads\" folder.", string(t.GetField(fieldFileName).Data))))
1553                         return res, err
1554                 }
1555         }
1556
1557         fileTransfer := cc.newFileTransfer(FolderUpload,
1558                 t.GetField(fieldFileName).Data,
1559                 t.GetField(fieldFilePath).Data,
1560                 t.GetField(fieldTransferSize).Data,
1561         )
1562
1563         fileTransfer.FolderItemCount = t.GetField(fieldFolderItemCount).Data
1564
1565         res = append(res, cc.NewReply(t, NewField(fieldRefNum, fileTransfer.ReferenceNumber)))
1566         return res, err
1567 }
1568
1569 // HandleUploadFile
1570 // Fields used in the request:
1571 // 201  File name
1572 // 202  File path
1573 // 204  File transfer options   "Optional
1574 // Used only to resume download, currently has value 2"
1575 // 108  File transfer size      "Optional used if download is not resumed"
1576 func HandleUploadFile(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1577         if !cc.Authorize(accessUploadFile) {
1578                 res = append(res, cc.NewErrReply(t, "You are not allowed to upload files."))
1579                 return res, err
1580         }
1581
1582         fileName := t.GetField(fieldFileName).Data
1583         filePath := t.GetField(fieldFilePath).Data
1584         transferOptions := t.GetField(fieldFileTransferOptions).Data
1585         transferSize := t.GetField(fieldTransferSize).Data // not sent for resume
1586
1587         var fp FilePath
1588         if filePath != nil {
1589                 if _, err = fp.Write(filePath); err != nil {
1590                         return res, err
1591                 }
1592         }
1593
1594         // Handle special cases for Upload and Drop Box folders
1595         if !cc.Authorize(accessUploadAnywhere) {
1596                 if !fp.IsUploadDir() && !fp.IsDropbox() {
1597                         res = append(res, cc.NewErrReply(t, fmt.Sprintf("Cannot accept upload of the file \"%v\" because you are only allowed to upload to the \"Uploads\" folder.", string(fileName))))
1598                         return res, err
1599                 }
1600         }
1601         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
1602         if err != nil {
1603                 return res, err
1604         }
1605
1606         if _, err := cc.Server.FS.Stat(fullFilePath); err == nil {
1607                 res = append(res, cc.NewErrReply(t, fmt.Sprintf("Cannot accept upload because there is already a file named \"%v\".  Try choosing a different name.", string(fileName))))
1608                 return res, err
1609         }
1610
1611         ft := cc.newFileTransfer(FileUpload, fileName, filePath, transferSize)
1612
1613         replyT := cc.NewReply(t, NewField(fieldRefNum, ft.ReferenceNumber))
1614
1615         // client has requested to resume a partially transferred file
1616         if transferOptions != nil {
1617
1618                 fileInfo, err := cc.Server.FS.Stat(fullFilePath + incompleteFileSuffix)
1619                 if err != nil {
1620                         return res, err
1621                 }
1622
1623                 offset := make([]byte, 4)
1624                 binary.BigEndian.PutUint32(offset, uint32(fileInfo.Size()))
1625
1626                 fileResumeData := NewFileResumeData([]ForkInfoList{
1627                         *NewForkInfoList(offset),
1628                 })
1629
1630                 b, _ := fileResumeData.BinaryMarshal()
1631
1632                 ft.TransferSize = offset
1633
1634                 replyT.Fields = append(replyT.Fields, NewField(fieldFileResumeData, b))
1635         }
1636
1637         res = append(res, replyT)
1638         return res, err
1639 }
1640
1641 func HandleSetClientUserInfo(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1642         if len(t.GetField(fieldUserIconID).Data) == 4 {
1643                 cc.Icon = t.GetField(fieldUserIconID).Data[2:]
1644         } else {
1645                 cc.Icon = t.GetField(fieldUserIconID).Data
1646         }
1647         if cc.Authorize(accessAnyName) {
1648                 cc.UserName = t.GetField(fieldUserName).Data
1649         }
1650
1651         // the options field is only passed by the client versions > 1.2.3.
1652         options := t.GetField(fieldOptions).Data
1653         if options != nil {
1654                 optBitmap := big.NewInt(int64(binary.BigEndian.Uint16(options)))
1655                 flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(cc.Flags)))
1656
1657                 flagBitmap.SetBit(flagBitmap, userFlagRefusePM, optBitmap.Bit(refusePM))
1658                 binary.BigEndian.PutUint16(cc.Flags, uint16(flagBitmap.Int64()))
1659
1660                 flagBitmap.SetBit(flagBitmap, userFLagRefusePChat, optBitmap.Bit(refuseChat))
1661                 binary.BigEndian.PutUint16(cc.Flags, uint16(flagBitmap.Int64()))
1662
1663                 // Check auto response
1664                 if optBitmap.Bit(autoResponse) == 1 {
1665                         cc.AutoReply = t.GetField(fieldAutomaticResponse).Data
1666                 } else {
1667                         cc.AutoReply = []byte{}
1668                 }
1669         }
1670
1671         for _, c := range sortedClients(cc.Server.Clients) {
1672                 res = append(res, *NewTransaction(
1673                         tranNotifyChangeUser,
1674                         c.ID,
1675                         NewField(fieldUserID, *cc.ID),
1676                         NewField(fieldUserIconID, cc.Icon),
1677                         NewField(fieldUserFlags, cc.Flags),
1678                         NewField(fieldUserName, cc.UserName),
1679                 ))
1680         }
1681
1682         return res, err
1683 }
1684
1685 // HandleKeepAlive responds to keepalive transactions with an empty reply
1686 // * HL 1.9.2 Client sends keepalive msg every 3 minutes
1687 // * HL 1.2.3 Client doesn't send keepalives
1688 func HandleKeepAlive(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1689         res = append(res, cc.NewReply(t))
1690
1691         return res, err
1692 }
1693
1694 func HandleGetFileNameList(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1695         fullPath, err := readPath(
1696                 cc.Server.Config.FileRoot,
1697                 t.GetField(fieldFilePath).Data,
1698                 nil,
1699         )
1700         if err != nil {
1701                 return res, err
1702         }
1703
1704         var fp FilePath
1705         if t.GetField(fieldFilePath).Data != nil {
1706                 if _, err = fp.Write(t.GetField(fieldFilePath).Data); err != nil {
1707                         return res, err
1708                 }
1709         }
1710
1711         // Handle special case for drop box folders
1712         if fp.IsDropbox() && !cc.Authorize(accessViewDropBoxes) {
1713                 res = append(res, cc.NewErrReply(t, "You are not allowed to view drop boxes."))
1714                 return res, err
1715         }
1716
1717         fileNames, err := getFileNameList(fullPath, cc.Server.Config.IgnoreFiles)
1718         if err != nil {
1719                 return res, err
1720         }
1721
1722         res = append(res, cc.NewReply(t, fileNames...))
1723
1724         return res, err
1725 }
1726
1727 // =================================
1728 //     Hotline private chat flow
1729 // =================================
1730 // 1. ClientA sends tranInviteNewChat to server with user ID to invite
1731 // 2. Server creates new ChatID
1732 // 3. Server sends tranInviteToChat to invitee
1733 // 4. Server replies to ClientA with new Chat ID
1734 //
1735 // A dialog box pops up in the invitee client with options to accept or decline the invitation.
1736 // If Accepted is clicked:
1737 // 1. ClientB sends tranJoinChat with fieldChatID
1738
1739 // HandleInviteNewChat invites users to new private chat
1740 func HandleInviteNewChat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1741         if !cc.Authorize(accessOpenChat) {
1742                 res = append(res, cc.NewErrReply(t, "You are not allowed to request private chat."))
1743                 return res, err
1744         }
1745
1746         // Client to Invite
1747         targetID := t.GetField(fieldUserID).Data
1748         newChatID := cc.Server.NewPrivateChat(cc)
1749
1750         // Check if target user has "Refuse private chat" flag
1751         binary.BigEndian.Uint16(targetID)
1752         targetClient := cc.Server.Clients[binary.BigEndian.Uint16(targetID)]
1753
1754         flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(targetClient.Flags)))
1755         if flagBitmap.Bit(userFLagRefusePChat) == 1 {
1756                 res = append(res,
1757                         *NewTransaction(
1758                                 tranServerMsg,
1759                                 cc.ID,
1760                                 NewField(fieldData, []byte(string(targetClient.UserName)+" does not accept private chats.")),
1761                                 NewField(fieldUserName, targetClient.UserName),
1762                                 NewField(fieldUserID, *targetClient.ID),
1763                                 NewField(fieldOptions, []byte{0, 2}),
1764                         ),
1765                 )
1766         } else {
1767                 res = append(res,
1768                         *NewTransaction(
1769                                 tranInviteToChat,
1770                                 &targetID,
1771                                 NewField(fieldChatID, newChatID),
1772                                 NewField(fieldUserName, cc.UserName),
1773                                 NewField(fieldUserID, *cc.ID),
1774                         ),
1775                 )
1776         }
1777
1778         res = append(res,
1779                 cc.NewReply(t,
1780                         NewField(fieldChatID, newChatID),
1781                         NewField(fieldUserName, cc.UserName),
1782                         NewField(fieldUserID, *cc.ID),
1783                         NewField(fieldUserIconID, cc.Icon),
1784                         NewField(fieldUserFlags, cc.Flags),
1785                 ),
1786         )
1787
1788         return res, err
1789 }
1790
1791 func HandleInviteToChat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1792         if !cc.Authorize(accessOpenChat) {
1793                 res = append(res, cc.NewErrReply(t, "You are not allowed to request private chat."))
1794                 return res, err
1795         }
1796
1797         // Client to Invite
1798         targetID := t.GetField(fieldUserID).Data
1799         chatID := t.GetField(fieldChatID).Data
1800
1801         res = append(res,
1802                 *NewTransaction(
1803                         tranInviteToChat,
1804                         &targetID,
1805                         NewField(fieldChatID, chatID),
1806                         NewField(fieldUserName, cc.UserName),
1807                         NewField(fieldUserID, *cc.ID),
1808                 ),
1809         )
1810         res = append(res,
1811                 cc.NewReply(
1812                         t,
1813                         NewField(fieldChatID, chatID),
1814                         NewField(fieldUserName, cc.UserName),
1815                         NewField(fieldUserID, *cc.ID),
1816                         NewField(fieldUserIconID, cc.Icon),
1817                         NewField(fieldUserFlags, cc.Flags),
1818                 ),
1819         )
1820
1821         return res, err
1822 }
1823
1824 func HandleRejectChatInvite(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1825         chatID := t.GetField(fieldChatID).Data
1826         chatInt := binary.BigEndian.Uint32(chatID)
1827
1828         privChat := cc.Server.PrivateChats[chatInt]
1829
1830         resMsg := append(cc.UserName, []byte(" declined invitation to chat")...)
1831
1832         for _, c := range sortedClients(privChat.ClientConn) {
1833                 res = append(res,
1834                         *NewTransaction(
1835                                 tranChatMsg,
1836                                 c.ID,
1837                                 NewField(fieldChatID, chatID),
1838                                 NewField(fieldData, resMsg),
1839                         ),
1840                 )
1841         }
1842
1843         return res, err
1844 }
1845
1846 // HandleJoinChat is sent from a v1.8+ Hotline client when the joins a private chat
1847 // Fields used in the reply:
1848 // * 115        Chat subject
1849 // * 300        User name with info (Optional)
1850 // * 300        (more user names with info)
1851 func HandleJoinChat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1852         chatID := t.GetField(fieldChatID).Data
1853         chatInt := binary.BigEndian.Uint32(chatID)
1854
1855         privChat := cc.Server.PrivateChats[chatInt]
1856
1857         // Send tranNotifyChatChangeUser to current members of the chat to inform of new user
1858         for _, c := range sortedClients(privChat.ClientConn) {
1859                 res = append(res,
1860                         *NewTransaction(
1861                                 tranNotifyChatChangeUser,
1862                                 c.ID,
1863                                 NewField(fieldChatID, chatID),
1864                                 NewField(fieldUserName, cc.UserName),
1865                                 NewField(fieldUserID, *cc.ID),
1866                                 NewField(fieldUserIconID, cc.Icon),
1867                                 NewField(fieldUserFlags, cc.Flags),
1868                         ),
1869                 )
1870         }
1871
1872         privChat.ClientConn[cc.uint16ID()] = cc
1873
1874         replyFields := []Field{NewField(fieldChatSubject, []byte(privChat.Subject))}
1875         for _, c := range sortedClients(privChat.ClientConn) {
1876                 user := User{
1877                         ID:    *c.ID,
1878                         Icon:  c.Icon,
1879                         Flags: c.Flags,
1880                         Name:  string(c.UserName),
1881                 }
1882
1883                 replyFields = append(replyFields, NewField(fieldUsernameWithInfo, user.Payload()))
1884         }
1885
1886         res = append(res, cc.NewReply(t, replyFields...))
1887         return res, err
1888 }
1889
1890 // HandleLeaveChat is sent from a v1.8+ Hotline client when the user exits a private chat
1891 // Fields used in the request:
1892 //   - 114      fieldChatID
1893 //
1894 // Reply is not expected.
1895 func HandleLeaveChat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1896         chatID := t.GetField(fieldChatID).Data
1897         chatInt := binary.BigEndian.Uint32(chatID)
1898
1899         privChat, ok := cc.Server.PrivateChats[chatInt]
1900         if !ok {
1901                 return res, nil
1902         }
1903
1904         delete(privChat.ClientConn, cc.uint16ID())
1905
1906         // Notify members of the private chat that the user has left
1907         for _, c := range sortedClients(privChat.ClientConn) {
1908                 res = append(res,
1909                         *NewTransaction(
1910                                 tranNotifyChatDeleteUser,
1911                                 c.ID,
1912                                 NewField(fieldChatID, chatID),
1913                                 NewField(fieldUserID, *cc.ID),
1914                         ),
1915                 )
1916         }
1917
1918         return res, err
1919 }
1920
1921 // HandleSetChatSubject is sent from a v1.8+ Hotline client when the user sets a private chat subject
1922 // Fields used in the request:
1923 // * 114        Chat ID
1924 // * 115        Chat subject    Chat subject string
1925 // Reply is not expected.
1926 func HandleSetChatSubject(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1927         chatID := t.GetField(fieldChatID).Data
1928         chatInt := binary.BigEndian.Uint32(chatID)
1929
1930         privChat := cc.Server.PrivateChats[chatInt]
1931         privChat.Subject = string(t.GetField(fieldChatSubject).Data)
1932
1933         for _, c := range sortedClients(privChat.ClientConn) {
1934                 res = append(res,
1935                         *NewTransaction(
1936                                 tranNotifyChatSubject,
1937                                 c.ID,
1938                                 NewField(fieldChatID, chatID),
1939                                 NewField(fieldChatSubject, t.GetField(fieldChatSubject).Data),
1940                         ),
1941                 )
1942         }
1943
1944         return res, err
1945 }
1946
1947 // HandleMakeAlias makes a filer alias using the specified path.
1948 // Fields used in the request:
1949 // 201  File name
1950 // 202  File path
1951 // 212  File new path   Destination path
1952 //
1953 // Fields used in the reply:
1954 // None
1955 func HandleMakeAlias(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1956         if !cc.Authorize(accessMakeAlias) {
1957                 res = append(res, cc.NewErrReply(t, "You are not allowed to make aliases."))
1958                 return res, err
1959         }
1960         fileName := t.GetField(fieldFileName).Data
1961         filePath := t.GetField(fieldFilePath).Data
1962         fileNewPath := t.GetField(fieldFileNewPath).Data
1963
1964         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
1965         if err != nil {
1966                 return res, err
1967         }
1968
1969         fullNewFilePath, err := readPath(cc.Server.Config.FileRoot, fileNewPath, fileName)
1970         if err != nil {
1971                 return res, err
1972         }
1973
1974         cc.logger.Debugw("Make alias", "src", fullFilePath, "dst", fullNewFilePath)
1975
1976         if err := cc.Server.FS.Symlink(fullFilePath, fullNewFilePath); err != nil {
1977                 res = append(res, cc.NewErrReply(t, "Error creating alias"))
1978                 return res, nil
1979         }
1980
1981         res = append(res, cc.NewReply(t))
1982         return res, err
1983 }
1984
1985 // HandleDownloadBanner handles requests for a new banner from the server
1986 // Fields used in the request:
1987 // None
1988 // Fields used in the reply:
1989 // 107  fieldRefNum                     Used later for transfer
1990 // 108  fieldTransferSize       Size of data to be downloaded
1991 func HandleDownloadBanner(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1992         fi, err := cc.Server.FS.Stat(filepath.Join(cc.Server.ConfigDir, cc.Server.Config.BannerFile))
1993         if err != nil {
1994                 return res, err
1995         }
1996
1997         ft := cc.newFileTransfer(bannerDownload, []byte{}, []byte{}, make([]byte, 4))
1998
1999         binary.BigEndian.PutUint32(ft.TransferSize, uint32(fi.Size()))
2000
2001         res = append(res, cc.NewReply(t,
2002                 NewField(fieldRefNum, ft.refNum[:]),
2003                 NewField(fieldTransferSize, ft.TransferSize),
2004         ))
2005
2006         return res, err
2007 }