KernelLand/Kernel/drv/pty.c

   1 /*
   2  * Acess2 Kernel
   3  * - By John Hodge (thePowersGang)
   4  *
   5  * drv/pty.c
   6  * - Pseudo Terminals
   7  */
   8 #define DEBUG   0
   9 #include <acess.h>
  10 #include <vfs.h>
  11 #include <fs_devfs.h>
  12 #include <drv_pty.h>
  13 #include <modules.h>
  14 #include <rwlock.h>
  15 #include <mutex.h>
  16 #include <posix_signals.h>
  17
  18 // === CONSTANTS ===
  19 #define OUTPUT_RINGBUFFER_LEN   1024    // Number of bytes in output queue before client blocks
  20 #define INPUT_RINGBUFFER_LEN    256     // Number of bytes in input queue before being dropped
  21 #define INPUT_LINE_LEN  256
  22
  23 // === TYPES ===
  24 struct sPTY
  25 {
  26         tPTY    *Next;
  27
  28         char    *Name;
  29          int    NumericName;
  30
  31         void    *OutputHandle;
  32         tPTY_OutputFcn  OutputFcn;
  33         tPTY_ReqResize  ReqResize;
  34         tPTY_ModeSet    ModeSet;
  35
  36         struct ptymode  Mode;
  37         struct ptydims  Dims;
  38
  39          int    HasHitEOF;
  40         tMutex  InputMutex;
  41          int    InputWritePos;
  42          int    InputReadPos;
  43         char    InputData[INPUT_RINGBUFFER_LEN];
  44
  45          int    LineLength;
  46         char    LineData[INPUT_LINE_LEN];
  47
  48         tMutex  OutputMutex;
  49          int    OutputWritePos;
  50          int    OutputReadPos;
  51         char    OutputData[OUTPUT_RINGBUFFER_LEN];
  52
  53         tVFS_Node       *ServerNode;
  54         tVFS_Node       ClientNode;
  55         tVFS_ACL        OwnerRW;
  56
  57         tPGID   ControllingProcGroup;
  58 };
  59
  60 // === PROTOTYPES ===
  61  int    PTY_Install(char **Arguments);
  62  int    PTY_ReadDir(tVFS_Node *Node, int Pos, char Name[FILENAME_MAX]);
  63 tVFS_Node       *PTY_FindDir(tVFS_Node *Node, const char *Name, Uint Flags);
  64
  65 size_t  _rb_write(void *buf, size_t buflen, int *rd, int *wr, const void *data, size_t len);
  66 size_t  _rb_read(void *buf, size_t buflen, int *rd, int *wr, void *data, size_t len);
  67 size_t  PTY_int_WriteInput(tPTY *PTY, const char *Input, size_t Length);
  68 size_t  PTY_int_SendInput(tPTY *PTY, const char *Input, size_t Length);
  69 // PTY_SendInput
  70 size_t  PTY_ReadClient(tVFS_Node *Node, off_t Offset, size_t Length, void *Buffer, Uint Flags);
  71 size_t  PTY_WriteClient(tVFS_Node *Node, off_t Offset, size_t Length, const void *Buffer, Uint Flags);
  72 void    PTY_ReferenceClient(tVFS_Node *Node);
  73 void    PTY_CloseClient(tVFS_Node *Node);
  74 size_t  PTY_ReadServer(tVFS_Node *Node, off_t Offset, size_t Length, void *Buffer, Uint Flags);
  75 size_t  PTY_WriteServer(tVFS_Node *Node, off_t Offset, size_t Length, const void *Buffer, Uint Flags);
  76 void    PTY_CloseServer(tVFS_Node *Node);
  77  int    PTY_IOCtl(tVFS_Node *Node, int ID, void *Arg);
  78
  79 // === GLOBALS ===
  80 MODULE_DEFINE(0, 0x100, PTY, PTY_Install, NULL, NULL);
  81 tVFS_NodeType   gPTY_NodeType_Root = {
  82         .TypeName = "PTY-Root",
  83         .ReadDir = PTY_ReadDir,
  84         .FindDir = PTY_FindDir,
  85 };
  86 tVFS_NodeType   gPTY_NodeType_Client = {
  87         .TypeName = "PTY-Client",
  88         .Read = PTY_ReadClient,
  89         .Write = PTY_WriteClient,
  90         .IOCtl = PTY_IOCtl,
  91         .Reference = PTY_ReferenceClient,
  92         .Close = PTY_CloseClient
  93 };
  94 tVFS_NodeType   gPTY_NodeType_Server = {
  95         .TypeName = "PTY-Server",
  96         .Read = PTY_ReadServer,
  97         .Write = PTY_WriteServer,
  98         .IOCtl = PTY_IOCtl,
  99         .Close = PTY_CloseServer
 100 };
 101 tDevFS_Driver   gPTY_Driver = {
 102         .Name = "pts",
 103         .RootNode = {
 104                 .Flags = VFS_FFLAG_DIRECTORY,
 105                 .Type = &gPTY_NodeType_Root,
 106                 .Size = -1
 107         }
 108 };
 109  int    giPTY_NumCount;
 110 tRWLock glPTY_NumPTYs;
 111 tPTY    *gpPTY_FirstNumPTY;
 112  int    giPTY_NamedCount;
 113 tRWLock glPTY_NamedPTYs;
 114 tPTY    *gpPTY_FirstNamedPTY;
 115
 116 // === CODE ===
 117 int PTY_Install(char **Arguments)
 118 {
 119         DevFS_AddDevice(&gPTY_Driver);
 120         return MODULE_ERR_OK;
 121 }
 122
 123 // --- Management ---
 124 tPTY *PTY_Create(const char *Name, void *Handle, tPTY_OutputFcn Output, tPTY_ReqResize ReqResize, tPTY_ModeSet ModeSet, const struct ptydims *InitialDims, const struct ptymode *InitialMode)
 125 {
 126         tPTY    **prev_np = NULL;
 127         size_t  namelen;
 128          int    idx = 1;
 129
 130         if( !Name )
 131                 Name = "";
 132
 133         if( Name[0] == '\0' )
 134         {
 135                 RWLock_AcquireWrite(&glPTY_NumPTYs);
 136                 // Get a pty ID if Name==NULL
 137                 prev_np = &gpPTY_FirstNumPTY;
 138                 for( tPTY *pty = gpPTY_FirstNumPTY; pty; prev_np = &pty->Next, pty = pty->Next )
 139                 {
 140                         if( pty->NumericName > idx )
 141                                 break;
 142                         idx ++;
 143                 }
 144                 namelen = snprintf(NULL,0, "%u", idx);
 145         }
 146         else if( Name[strlen(Name)-1] == '#' )
 147         {
 148                 // Sequenced PTYs
 149                 // - "gui#" would translate to "gui0", "gui1", "gui2", ...
 150                 //   whichever is free
 151                 prev_np = &gpPTY_FirstNamedPTY;
 152
 153                 RWLock_AcquireWrite(&glPTY_NamedPTYs);
 154                 idx = 0;
 155                 namelen = strlen(Name)-1;
 156                 for( tPTY *pty = gpPTY_FirstNamedPTY; pty; prev_np = &pty->Next, pty = pty->Next )
 157                 {
 158                          int    cmp = strncmp(pty->Name, Name, namelen);
 159                         if( cmp < 0 )
 160                                 continue ;
 161                         if( cmp > 0 )
 162                                 break;
 163
 164                         // Skip non-numbered
 165                         if( pty->Name[namelen] == '\0' )
 166                                 continue ;
 167
 168                         // Find an unused index
 169                         char    *name_end;
 170                          int    this_idx = strtol(pty->Name+namelen, &name_end, 10);
 171                         if( *name_end != '\0' )
 172                                 continue;
 173                         if( this_idx > idx )
 174                                 break;
 175                         idx ++;
 176                 }
 177
 178                 namelen += snprintf(NULL, 0, "%u", idx);
 179         }
 180         else
 181         {
 182                 prev_np = &gpPTY_FirstNamedPTY;
 183
 184                 // Check the name isn't decimal
 185                 char *end;
 186                 if( strtol(Name, &end, 10) != 0 && *end == '\0' ) {
 187                         errno = EINVAL;
 188                         return NULL;
 189                 }
 190
 191                 RWLock_AcquireWrite(&glPTY_NamedPTYs);
 192                 // Detect duplicates
 193                 for( tPTY *pty = gpPTY_FirstNamedPTY; pty; prev_np = &pty->Next, pty = pty->Next )
 194                 {
 195                          int    cmp = strcmp(pty->Name, Name);
 196                         if( cmp < 0 )
 197                                 continue;
 198                         if( cmp == 0 ) {
 199                                 RWLock_Release(&glPTY_NamedPTYs);
 200                                 errno = EEXIST;
 201                                 return NULL;
 202                         }
 203                         break;
 204                 }
 205                 namelen = strlen(Name);
 206                 idx = -1;
 207         }
 208
 209         tPTY *ret = calloc(sizeof(tPTY) + namelen + 1, 1);
 210         if(!ret) {
 211                 errno = ENOMEM;
 212                 return NULL;
 213         }
 214
 215         // - List maintainance
 216         ret->Next = *prev_np;
 217         *prev_np = ret;
 218         // - PTY Name (Used by VT)
 219         ret->Name = (char*)(ret + 1);
 220         if( idx == -1 )
 221                 strcpy(ret->Name, Name);
 222         else if( Name[0] )
 223                 sprintf(ret->Name, "%.*s%u", strlen(Name)-1, Name, idx);
 224         else
 225                 sprintf(ret->Name, "%u", idx);
 226         ret->NumericName = idx;
 227         // - Output function and handle (same again)
 228         ret->OutputHandle = Handle;
 229         ret->OutputFcn = Output;
 230         ret->ReqResize = ReqResize;
 231         ret->ModeSet = ModeSet;
 232         // - Initialise modes
 233         if( InitialDims )
 234                 ret->Dims = *InitialDims;
 235         if( InitialMode )
 236                 ret->Mode = *InitialMode;
 237         // - Client node
 238         ret->ClientNode.ImplPtr = ret;
 239         ret->ClientNode.Type = &gPTY_NodeType_Client;
 240         ret->ClientNode.UID = Threads_GetUID();
 241         ret->ClientNode.GID = Threads_GetGID();
 242         ret->ClientNode.NumACLs = 1;
 243         ret->ClientNode.ACLs = &ret->OwnerRW;
 244         // - Owner Read-Write ACL
 245         ret->OwnerRW.Ent.ID = Threads_GetUID();
 246         ret->OwnerRW.Perm.Perms = -1;
 247
 248         if( Name[0] ) {
 249                 giPTY_NamedCount ++;
 250                 RWLock_Release(&glPTY_NamedPTYs);
 251         }
 252         else {
 253                 giPTY_NumCount ++;
 254                 RWLock_Release(&glPTY_NumPTYs);
 255         }
 256
 257         return ret;
 258 }
 259
 260 int PTY_SetAttrib(tPTY *PTY, const struct ptydims *Dims, const struct ptymode *Mode, int WasClient)
 261 {
 262         if( Mode )
 263         {
 264                 // (for now) userland terminals can't be put into framebuffer mode
 265                 // - Userland PTYs are streams, framebuffer is a block
 266                 if( !PTY->OutputFcn && (Mode->OutputMode & PTYOMODE_BUFFMT) == PTYBUFFMT_FB ) {
 267                         errno = EINVAL;
 268                         return -1;
 269                 }
 270                 if( WasClient )
 271                 {
 272                         if( PTY->ModeSet && PTY->ModeSet(PTY->OutputHandle, Mode) )
 273                         {
 274                                 errno = EINVAL;
 275                                 return -1;
 276                         }
 277                         else if( !PTY->OutputFcn )
 278                         {
 279                                 Log_Warning("PTY", "TODO: Inform server of client SETMODE, halt output");
 280                                 // Block slave write until master ACKs
 281                                 // 0-length read on master indicates need to GETMODE
 282                         }
 283                 }
 284                 else
 285                 {
 286                         // Should the client be informed that the server just twiddled the modes?
 287                         Log_Warning("PTY", "Server changed mode, TODO: inform client?");
 288                 }
 289                 LOG("PTY %p mode set to {0%o, 0%o}", PTY, Mode->InputMode, Mode->OutputMode);
 290                 PTY->Mode = *Mode;
 291         }
 292         if( Dims )
 293         {
 294                 if( WasClient )
 295                 {
 296                         // Poke the server?
 297                         if( PTY->ReqResize && PTY->ReqResize(PTY->OutputHandle, Dims) )
 298                         {
 299                                 errno = EINVAL;
 300                                 return -1;
 301                         }
 302                         else if( !PTY->OutputFcn )
 303                         {
 304                                 // Inform server process... somehow
 305                                 Log_Warning("PTY", "TODO: Inform server of client resize request");
 306                         }
 307                 }
 308                 else
 309                 {
 310                         // SIGWINSZ to client
 311                         Threads_SignalGroup(PTY->ControllingProcGroup, SIGWINCH);
 312                 }
 313                 LOG("PTY %p dims set to %ix%i", PTY, Dims->W, Dims->H);
 314                 PTY->Dims = *Dims;
 315         }
 316         return 0;
 317 }
 318
 319 void PTY_Close(tPTY *PTY)
 320 {
 321
 322 }
 323
 324 size_t _rb_write(void *buf, size_t buflen, int *rd, int *wr, const void *data, size_t len)
 325 {
 326         size_t space = (*rd - *wr + buflen - 1) % buflen;
 327         len = MIN(space, len);
 328         if(*wr + len >= buflen) {
 329                 size_t prelen = buflen - *wr;
 330                 memcpy((char*)buf + *wr, data, prelen);
 331                 memcpy(buf, (char*)data + prelen, len - prelen);
 332                 *wr = len - prelen;
 333         }
 334         else {
 335                 memcpy((char*)buf + *wr, data, len);
 336                 *wr += len;
 337         }
 338         return len;
 339 }
 340 size_t _rb_read(void *buf, size_t buflen, int *rd, int *wr, void *data, size_t len)
 341 {
 342         size_t space = (*wr - *rd + buflen) % buflen;
 343         len = MIN(space, len);
 344         if(*rd + len >= buflen) {
 345                 size_t prelen = buflen - *rd;
 346                 memcpy(data, (char*)buf + *rd, prelen);
 347                 memcpy((char*)data + prelen, buf, len - prelen);
 348                 *rd = len - prelen;
 349         }
 350         else {
 351                 memcpy(data, (char*)buf + *rd, len);
 352                 *rd += len;
 353         }
 354         return len;
 355 }
 356
 357 size_t PTY_int_WriteInput(tPTY *PTY, const char *Input, size_t Length)
 358 {
 359         size_t  ret;
 360
 361         Mutex_Acquire(&PTY->InputMutex);
 362
 363         ret = _rb_write(PTY->InputData, INPUT_RINGBUFFER_LEN, &PTY->InputReadPos, &PTY->InputWritePos,
 364                 Input, Length);
 365
 366         Mutex_Release(&PTY->InputMutex);
 367
 368         VFS_MarkAvaliable(&PTY->ClientNode, 1);
 369         if(ret < Length && PTY->ServerNode)
 370                 VFS_MarkFull(PTY->ServerNode, 1);
 371
 372         return ret;
 373 }
 374
 375 size_t PTY_int_SendInput(tPTY *PTY, const char *Input, size_t Length)
 376 {
 377         size_t  ret = 1, print = 1;
 378
 379         // Input mode stuff only counts for text output mode
 380         // - Any other mode sends Uint32 keypresses
 381         if( (PTY->Mode.OutputMode & PTYOMODE_BUFFMT) != PTYBUFFMT_TEXT )
 382                 return PTY_int_WriteInput(PTY, Input, Length);
 383         // If in raw mode, flush directly
 384         if( (PTY->Mode.InputMode & PTYIMODE_RAW) )
 385                 return PTY_int_WriteInput(PTY, Input, Length);
 386
 387         if( PTY->Mode.InputMode & PTYIMODE_CANON )
 388         {
 389                 const char      char_bs = '\b';
 390                 switch(Input[0])
 391                 {
 392                 case 3: // INTR - ^C
 393                         // Send SIGINT
 394                         Threads_SignalGroup(PTY->ControllingProcGroup, SIGINT);
 395                         print = 0;
 396                         break;
 397                 case 4: // EOF - ^D
 398                         PTY_int_WriteInput(PTY, PTY->LineData, PTY->LineLength);
 399                         PTY->HasHitEOF = (PTY->LineLength == 0);
 400                         PTY->LineLength = 0;
 401                         print = 0;
 402                         break;
 403                 case 8: // Backspace
 404                         if(PTY->LineLength != 0)
 405                                 PTY->LineLength --;
 406                         break;
 407                 case 'w'-'a':   // Word erase
 408                         while(PTY->LineLength != 0 && isalnum(PTY->LineData[--PTY->LineLength]))
 409                                 PTY_WriteClient(&PTY->ClientNode, 0, 1, &char_bs, 0);
 410                         print = 0;
 411                         break;
 412                 case 'u'-'a':   // Kill
 413                         while(PTY->LineLength > 0)
 414                                 PTY_WriteClient(&PTY->ClientNode, 0, 1, &char_bs, 0);
 415                         print = 0;
 416                         break;
 417                 case 'v'-'a':
 418                         Input ++;
 419                         Length --;
 420                         ret ++;
 421                         goto _default;
 422                 case '\0':
 423                 case '\n':
 424                         if(PTY->LineLength == INPUT_LINE_LEN) {
 425                                 PTY_int_WriteInput(PTY, PTY->LineData, PTY->LineLength);
 426                                 PTY->LineLength = 0;
 427                         }
 428                         PTY->LineData[PTY->LineLength++] = '\n';
 429                         PTY_int_WriteInput(PTY, PTY->LineData, PTY->LineLength);
 430                         PTY->LineLength = 0;
 431                         break;
 432                 // TODO: Handle ^[[D and ^[[C for in-line editing, also ^[[1~/^[[4~ (home/end)
 433                 //case 0x1B:
 434                 //      break;
 435                 default:
 436                 _default:
 437                         if(PTY->LineLength == INPUT_LINE_LEN) {
 438                                 PTY_int_WriteInput(PTY, PTY->LineData, PTY->LineLength);
 439                                 PTY->LineLength = 0;
 440                         }
 441                         PTY->LineData[PTY->LineLength++] = Input[0];
 442                         break;
 443                 }
 444         }
 445         else
 446         {
 447                 #if 0
 448                 if( PTY->Mode.InputMode & PTYIMODE_NLCR )
 449                 {
 450                         if( Input[0] == '\n' ) {
 451                                 char ch = '\r';
 452                                 ret = PTY_int_WriteInput(PTY, &ch, 1);
 453                         }
 454                         else {
 455                                  int    i;
 456                                 for( i = 0; i < Length && Input[i] != '\n'; i ++ )
 457                                         ;
 458                                 ret = PTY_int_WriteInput(PTY, Input, i);
 459                         }
 460                 }
 461                 // TODO: CRNL mode?
 462                 else
 463                 #endif
 464                         ret = PTY_int_WriteInput(PTY, Input, Length);
 465         }
 466
 467         // Echo if requested
 468         if( PTY->Mode.InputMode & PTYIMODE_ECHO )
 469         {
 470                 PTY_WriteClient(&PTY->ClientNode, 0, print, Input, 0);
 471         }
 472
 473         return ret;
 474 }
 475
 476 size_t PTY_SendInput(tPTY *PTY, const char *Input, size_t Length)
 477 {
 478         size_t ret = 0;
 479         while( ret < Length && !PTY->ClientNode.BufferFull )
 480         {
 481                 // TODO: Detect blocking?
 482                 ret += PTY_int_SendInput(PTY, Input + ret, Length - ret);
 483         }
 484         return ret;
 485 }
 486
 487 // --- VFS ---
 488 int PTY_ReadDir(tVFS_Node *Node, int Pos, char Name[FILENAME_MAX])
 489 {
 490         tPTY    *pty = NULL;
 491          int    idx = Pos;
 492         if( idx < giPTY_NumCount )
 493         {
 494                 RWLock_AcquireRead(&glPTY_NumPTYs);
 495                 for( pty = gpPTY_FirstNumPTY; pty && idx; pty = pty->Next )
 496                         idx --;
 497                 RWLock_Release(&glPTY_NumPTYs);
 498         }
 499         else if( idx < (giPTY_NumCount + giPTY_NamedCount) )
 500         {
 501                 idx -= giPTY_NumCount;
 502                 RWLock_AcquireRead(&glPTY_NamedPTYs);
 503                 for( pty = gpPTY_FirstNamedPTY; pty && idx; pty = pty->Next )
 504                         idx --;
 505                 RWLock_Release(&glPTY_NamedPTYs);
 506         }
 507
 508         if( !pty ) {
 509                 return -1;
 510         }
 511
 512         strncpy(Name, pty->Name, FILENAME_MAX);
 513         return 0;
 514 }
 515
 516 tVFS_Node *PTY_FindDir(tVFS_Node *Node, const char *Name, Uint Flags)
 517 {
 518         char    *end;
 519          int    num = strtol(Name, &end, 10);
 520
 521         if( strcmp(Name, "ptmx") == 0 ) {
 522                 tVFS_Node       *ret = calloc(sizeof(tVFS_Node), 1);
 523                 ret->Size = -1;
 524                 ret->Type = &gPTY_NodeType_Server;
 525                 return ret;
 526         }
 527
 528         if( Name[0] == '\0' )
 529                 return NULL;
 530
 531         tPTY    *ret = NULL;
 532         if( num && end[0] == '\0' )
 533         {
 534                 // Numeric name
 535                 RWLock_AcquireRead(&glPTY_NumPTYs);
 536                 for( tPTY *pty = gpPTY_FirstNumPTY; pty; pty = pty->Next )
 537                 {
 538                         if( pty->NumericName > num )
 539                                 break;
 540                         if( pty->NumericName == num ) {
 541                                 ret = pty;
 542                                 break;
 543                         }
 544                 }
 545                 RWLock_Release(&glPTY_NumPTYs);
 546         }
 547         else
 548         {
 549                 // String name
 550                 RWLock_AcquireRead(&glPTY_NamedPTYs);
 551                 for( tPTY *pty = gpPTY_FirstNamedPTY; pty; pty = pty->Next )
 552                 {
 553                         int cmp = strcmp(pty->Name, Name);
 554                         if(cmp > 0)
 555                                 break;
 556                         if(cmp == 0 ) {
 557                                 ret = pty;
 558                                 break;
 559                         }
 560                 }
 561                 RWLock_Release(&glPTY_NamedPTYs);
 562         }
 563 //      Debug("PTY_FindDir('%s') returned %p", Name, &ret->ClientNode);
 564         if( ret ) {
 565                 tVFS_Node       *retnode = &ret->ClientNode;
 566                 retnode->ReferenceCount ++;
 567                 return retnode;
 568         }
 569         else
 570                 return NULL;
 571 }
 572
 573 //\! Read from the client's input
 574 size_t PTY_ReadClient(tVFS_Node *Node, off_t Offset, size_t Length, void *Buffer, Uint Flags)
 575 {
 576         tPTY *pty = Node->ImplPtr;
 577
 578         // Read from flushed queue
 579         tTime   timeout_z = 0, *timeout = (Flags & VFS_IOFLAG_NOBLOCK) ? &timeout_z : NULL;
 580          int    rv;
 581 _select:
 582         // If server has disconnected, return EIO
 583         if( pty->ServerNode && pty->ServerNode->ReferenceCount == 0 ) {
 584                 //Threads_PostSignal(SIGPIPE);
 585                 errno = EIO;
 586                 return -1;
 587         }
 588         // Wait for data to be ready
 589         rv = VFS_SelectNode(Node, VFS_SELECT_READ, timeout, "PTY_ReadClient");
 590         if(!rv) {
 591                 errno = (timeout ? EWOULDBLOCK : EINTR);
 592                 return -1;
 593         }
 594
 595         Mutex_Acquire(&pty->InputMutex);
 596         Length = _rb_read(pty->InputData, INPUT_RINGBUFFER_LEN, &pty->InputReadPos, &pty->InputWritePos,
 597                 Buffer, Length);
 598         if( Length && pty->ServerNode )
 599                 VFS_MarkFull(pty->ServerNode, 0);
 600         Mutex_Release(&pty->InputMutex);
 601
 602         if(pty->InputReadPos == pty->InputWritePos)
 603                 VFS_MarkAvaliable(Node, 0);
 604
 605         if(Length == 0 && !pty->HasHitEOF) {
 606                 goto _select;
 607         }
 608         pty->HasHitEOF = 0;
 609
 610         return Length;
 611 }
 612
 613 //\! Write to the client's output
 614 size_t PTY_WriteClient(tVFS_Node *Node, off_t Offset, size_t Length, const void *Buffer, Uint Flags)
 615 {
 616         tPTY *pty = Node->ImplPtr;
 617
 618         // If the server has terminated, send SIGPIPE
 619         if( pty->ServerNode && pty->ServerNode->ReferenceCount == 0 )
 620         {
 621                 Threads_PostSignal(SIGPIPE);
 622                 errno = EIO;
 623                 return -1;
 624         }
 625
 626         // Write to either FIFO or directly to output function
 627         if( pty->OutputFcn ) {
 628                 pty->OutputFcn(pty->OutputHandle, Length, Buffer);
 629                 return Length;
 630         }
 631
 632         // FIFO
 633         size_t remaining = Length;
 634         do
 635         {
 636                 tTime   timeout_z, *timeout = (Flags & VFS_IOFLAG_NOBLOCK) ? &timeout_z : NULL;
 637                  int    rv;
 638
 639                 rv = VFS_SelectNode(Node, VFS_SELECT_WRITE, timeout, "PTY_WriteClient");
 640                 if(!rv) {
 641                         errno = (timeout ? EWOULDBLOCK : EINTR);
 642                         return -1;
 643                 }
 644
 645                 // Write to output ringbuffer
 646                 size_t written = _rb_write(pty->OutputData, OUTPUT_RINGBUFFER_LEN,
 647                         &pty->OutputReadPos, &pty->OutputWritePos,
 648                         Buffer, remaining);
 649                 LOG("Wrote %i of %i : '%.*s'", written, remaining, written, Buffer);
 650                 VFS_MarkAvaliable(pty->ServerNode, 1);
 651                 if( (pty->OutputWritePos + 1) % OUTPUT_RINGBUFFER_LEN == pty->OutputReadPos )
 652                         VFS_MarkFull(Node, 1);
 653
 654                 remaining -= written;
 655                 Buffer = (const char*)Buffer + written;
 656         } while( remaining > 0 || (Flags & VFS_IOFLAG_NOBLOCK) );
 657
 658         return Length - remaining;
 659 }
 660
 661 void PTY_ReferenceClient(tVFS_Node *Node)
 662 {
 663         Node->ReferenceCount ++;
 664 }
 665
 666 void PTY_CloseClient(tVFS_Node *Node)
 667 {
 668         tPTY    *pty = Node->ImplPtr;
 669         Node->ReferenceCount --;
 670
 671         // Remove PID from list
 672         // TODO: Maintain list of client processes
 673
 674         // Free structure if this was the last open handle
 675         if( Node->ReferenceCount > 0 )
 676                 return ;
 677         if( pty->ServerNode && pty->ServerNode->ReferenceCount == 0 )
 678         {
 679                 // Free the structure! (Should be off the PTY list now)
 680                 free(pty->ServerNode);
 681                 free(pty);
 682         }
 683 }
 684
 685 //\! Read from the client's output
 686 size_t PTY_ReadServer(tVFS_Node *Node, off_t Offset, size_t Length, void *Buffer, Uint Flags)
 687 {
 688         tPTY *pty = Node->ImplPtr;
 689         if( !pty ) {
 690                 errno = EIO;
 691                 return -1;
 692         }
 693
 694         // TODO: Prevent two servers fighting over client's output
 695         if( pty->OutputFcn )
 696         {
 697                 // Kernel-land PTYs can't be read from userland
 698                 return 0;
 699         }
 700
 701         // Read back from fifo
 702         tTime   timeout_z = 0, *timeout = (Flags & VFS_IOFLAG_NOBLOCK) ? &timeout_z : NULL;
 703         int rv = VFS_SelectNode(Node, VFS_SELECT_READ, timeout, "PTY_ReadServer");
 704         if(!rv) {
 705                 errno = (timeout ? EWOULDBLOCK : EINTR);
 706                 return -1;
 707         }
 708
 709         Length = _rb_read(pty->OutputData, OUTPUT_RINGBUFFER_LEN,
 710                 &pty->OutputReadPos, &pty->OutputWritePos,
 711                 Buffer, Length);
 712         LOG("Read %i '%.*s'", Length, Length, Buffer);
 713         if( pty->OutputReadPos == pty->OutputWritePos )
 714                 VFS_MarkAvaliable(Node, 0);
 715         VFS_MarkFull(&pty->ClientNode, 0);
 716
 717         return Length;
 718 }
 719
 720 //\! Write to the client's input
 721 size_t PTY_WriteServer(tVFS_Node *Node, off_t Offset, size_t Length, const void *Buffer, Uint Flags)
 722 {
 723         tPTY    *pty = Node->ImplPtr;
 724         if( !pty ) {
 725                 errno = EIO;
 726                 return -1;
 727         }
 728
 729         tTime   timeout_z = 0, *timeout = (Flags & VFS_IOFLAG_NOBLOCK) ? &timeout_z : NULL;
 730         int rv = VFS_SelectNode(Node, VFS_SELECT_WRITE, timeout, "PTY_WriteServer");
 731         if(!rv) {
 732                 errno = (timeout ? EWOULDBLOCK : EINTR);
 733                 return -1;
 734         }
 735         size_t  used = 0;
 736         do {
 737                 used += PTY_SendInput(Node->ImplPtr, Buffer, Length);
 738         } while( used < Length && !(Flags & VFS_IOFLAG_NOBLOCK) );
 739
 740         if( (pty->InputWritePos+1)%INPUT_RINGBUFFER_LEN == pty->InputReadPos )
 741                 VFS_MarkFull(Node, 1);
 742         return used;
 743 }
 744
 745 void PTY_CloseServer(tVFS_Node *Node)
 746 {
 747         tPTY    *pty = Node->ImplPtr;
 748         // Dereference node
 749         Node->ReferenceCount --;
 750         // If reference count == 0, remove from main list
 751         if( Node->ReferenceCount > 0 )
 752                 return ;
 753
 754         // Locate on list and remove
 755         tPTY    **prev_np;
 756         if( pty->NumericName == -1 ) {
 757                 RWLock_AcquireWrite(&glPTY_NamedPTYs);
 758                 prev_np = &gpPTY_FirstNamedPTY;
 759         }
 760         else {
 761                 RWLock_AcquireWrite(&glPTY_NumPTYs);
 762                 prev_np = &gpPTY_FirstNumPTY;
 763         }
 764
 765         // Search list until *prev_np is equal to pty
 766         for( tPTY *tmp = *prev_np; *prev_np != pty && tmp; prev_np = &tmp->Next, tmp = tmp->Next )
 767                 ;
 768
 769         // Remove
 770         if( *prev_np != pty ) {
 771                 Log_Error("PTY", "PTY %p(%i/%s) not on list at deletion time", pty, pty->NumericName, pty->Name);
 772         }
 773         else {
 774                 *prev_np = pty->Next;
 775         }
 776
 777         // Clean up lock
 778         if( pty->NumericName == -1 ) {
 779                 RWLock_Release(&glPTY_NamedPTYs);
 780                 giPTY_NamedCount --;
 781         }
 782         else {
 783                 RWLock_Release(&glPTY_NumPTYs);
 784                 giPTY_NumCount --;
 785         }
 786
 787         // Send SIGHUP to controling PGID
 788         if( pty->ControllingProcGroup > 0 ) {
 789                 Threads_SignalGroup(pty->ControllingProcGroup, SIGHUP);
 790         }
 791
 792         // If there are no open children, we can safely free this PTY
 793         if( pty->ClientNode.ReferenceCount == 0 ) {
 794                 free(Node);
 795                 free(pty);
 796         }
 797 }
 798
 799 int PTY_IOCtl(tVFS_Node *Node, int ID, void *Data)
 800 {
 801         tPTY    *pty = Node->ImplPtr;
 802         struct ptymode  *mode = Data;
 803         struct ptydims  *dims = Data;
 804
 805         int     is_server = !pty || Node == pty->ServerNode;
 806
 807         switch(ID)
 808         {
 809         case DRV_IOCTL_TYPE:    return DRV_TYPE_TERMINAL;
 810         case DRV_IOCTL_IDENT:   memcpy(Data, "PTY\0", 4);       return 0;
 811         case DRV_IOCTL_VERSION: return 0x100;
 812         case DRV_IOCTL_LOOKUP:  return 0;
 813
 814         case PTY_IOCTL_GETMODE:
 815                 if( !pty )      return 0;
 816                 if( !CheckMem(Data, sizeof(*mode)) ) { errno = EINVAL; return -1; }
 817                 *mode = pty->Mode;
 818                 // TODO: ACK client's SETMODE
 819                 return 0;
 820         case PTY_IOCTL_SETMODE:
 821                 if( !pty )      return 0;
 822                 if( !CheckMem(Data, sizeof(*mode)) ) { errno = EINVAL; return -1; }
 823                 PTY_SetAttrib(pty, NULL, mode, !is_server);
 824                 return 0;
 825         case PTY_IOCTL_GETDIMS:
 826                 if( !pty )      return 0;
 827                 if( !CheckMem(Data, sizeof(*dims)) ) { errno = EINVAL; return -1; }
 828                 *dims = pty->Dims;
 829                 return 0;
 830         case PTY_IOCTL_SETDIMS:
 831                 if( !pty )      return 0;
 832                 if( !CheckMem(Data, sizeof(*dims)) ) { errno = EINVAL; return -1; }
 833                 PTY_SetAttrib(pty, dims, NULL, !is_server);
 834                 return 0;
 835         case PTY_IOCTL_GETID:
 836                 if( pty )
 837                 {
 838                         size_t  len = strlen(pty->Name)+1;
 839                         if( Data )
 840                         {
 841                                 if( !CheckMem(Data, len) ) { errno = EINVAL; return -1; }
 842                                 strcpy(Data, pty->Name);
 843                         }
 844                         return len;
 845                 }
 846                 return 0;
 847         case PTY_IOCTL_SETID:
 848                 if( Data && !CheckString(Data) ) { errno = EINVAL; return -1; }
 849                 if( pty )       return EALREADY;
 850                 pty = PTY_Create(Data, NULL, NULL,NULL, NULL, NULL,NULL);
 851                 if(pty == NULL)
 852                         return 1;
 853                 Node->ImplPtr = pty;
 854                 pty->ServerNode = Node;
 855                 return 0;
 856         case PTY_IOCTL_SETPGRP:
 857                 // TODO: Should this only be done by client?
 858                 if( Data )
 859                 {
 860                         if( !CheckMem(Data, sizeof(tPGID)) ) { errno = EINVAL; return -1; }
 861                         pty->ControllingProcGroup = *(tPGID*)Data;
 862                         Log_Debug("PTY", "Set controlling PGID to %i", pty->ControllingProcGroup);
 863                 }
 864                 return pty->ControllingProcGroup;
 865         }
 866         errno = ENOSYS;
 867         return -1;
 868 }
 869