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