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