Kernel/drv/fifo.c

   1 /* AcessOS
   2  * FIFO Pipe Driver
   3  */
   4 #include <common.h>
   5 #include <modules.h>
   6 #include <fs_devfs.h>
   7
   8 // === CONSTANTS ===
   9 #define DEFAULT_RING_SIZE       2048
  10 #define PF_BLOCKING             1
  11
  12 // === TYPES ===
  13 typedef struct sPipe {
  14         struct sPipe    *Next;
  15         char    *Name;
  16         tVFS_Node       Node;
  17         Uint    Flags;
  18          int    ReadPos;
  19          int    WritePos;
  20          int    BufSize;
  21         char    *Buffer;
  22 } tPipe;
  23
  24 // === PROTOTYPES ===
  25  int    FIFO_Install(char **Arguments);
  26  int    FIFO_IOCtl(tVFS_Node *Node, int Id, void *Data);
  27 char    *FIFO_ReadDir(tVFS_Node *Node, int Id);
  28 tVFS_Node       *FIFO_FindDir(tVFS_Node *Node, char *Filename);
  29  int    FIFO_MkNod(tVFS_Node *Node, char *Name, Uint Flags);
  30 void    FIFO_Close(tVFS_Node *Node);
  31  int    FIFO_Relink(tVFS_Node *Node, char *OldName, char *NewName);
  32 Uint64  FIFO_Read(tVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer);
  33 Uint64  FIFO_Write(tVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer);
  34 tPipe   *FIFO_Int_NewPipe(int Size, char *Name);
  35
  36 // === GLOBALS ===
  37 MODULE_DEFINE(0, 0x0032, FIFO, FIFO_Install, NULL, NULL);
  38 tDevFS_Driver   gFIFO_DriverInfo = {
  39         NULL, "fifo",
  40         {
  41         .NumACLs = 1,
  42         .ACLs = &gVFS_ACL_EveryoneRW,
  43         .Flags = VFS_FFLAG_DIRECTORY,
  44         .ReadDir = FIFO_ReadDir,
  45         .FindDir = FIFO_FindDir,
  46         .MkNod = FIFO_MkNod,
  47         .Relink = FIFO_Relink,
  48         .IOCtl = FIFO_IOCtl
  49         }
  50 };
  51 tVFS_Node       gFIFO_AnonNode = {
  52         .NumACLs = 1,
  53         .ACLs = &gVFS_ACL_EveryoneRW,
  54         };
  55 tPipe   *gFIFO_NamedPipes = NULL;
  56
  57 // === CODE ===
  58 /**
  59  * \fn int FIFO_Install(char **Options)
  60  * \brief Installs the FIFO Driver
  61  */
  62 int FIFO_Install(char **Options)
  63 {
  64         DevFS_AddDevice( &gFIFO_DriverInfo );
  65         return 0;
  66 }
  67
  68 /**
  69  * \fn int FIFO_IOCtl(tVFS_Node *Node, int Id, void *Data)
  70  */
  71 int FIFO_IOCtl(tVFS_Node *Node, int Id, void *Data)
  72 {
  73         return 0;
  74 }
  75
  76 /**
  77  * \fn char *FIFO_ReadDir(tVFS_Node *Node, int Id)
  78  * \brief Reads from the FIFO root
  79  */
  80 char *FIFO_ReadDir(tVFS_Node *Node, int Id)
  81 {
  82         tPipe   *tmp = gFIFO_NamedPipes;
  83         // Entry 0 is Anon Pipes
  84         if(Id == 0)     return strdup("anon");
  85
  86         // Find the id'th node
  87         while(--Id && tmp)      tmp = tmp->Next;
  88         // If node found, return it
  89         if(tmp) return strdup(tmp->Name);
  90         // else error return
  91         return NULL;
  92 }
  93
  94 /**
  95  * \fn tVFS_Node *FIFO_FindDir(tVFS_Node *Node, char *Filename)
  96  * \brief Find a file in the FIFO root
  97  * \note Creates an anon pipe if anon is requested
  98  */
  99 tVFS_Node *FIFO_FindDir(tVFS_Node *Node, char *Filename)
 100 {
 101         tPipe   *tmp;
 102         if(!Filename)   return NULL;
 103
 104         // NULL String Check
 105         if(Filename[0] == '\0') return NULL;
 106
 107         // Anon Pipe
 108         if(Filename[0] == 'a' && Filename[1] == 'n'
 109         && Filename[2] == 'o' && Filename[3] == 'n'
 110         && Filename[4] == '\0') {
 111                 tmp = FIFO_Int_NewPipe(DEFAULT_RING_SIZE, "anon");
 112                 return &tmp->Node;
 113         }
 114
 115         // Check Named List
 116         tmp = gFIFO_NamedPipes;
 117         while(tmp)
 118         {
 119                 if(strcmp(tmp->Name, Filename) == 0)
 120                         return &tmp->Node;
 121                 tmp = tmp->Next;
 122         }
 123         return NULL;
 124 }
 125
 126 /**
 127  * \fn int FIFO_MkNod(tVFS_Node *Node, char *Name, Uint Flags)
 128  */
 129 int FIFO_MkNod(tVFS_Node *Node, char *Name, Uint Flags)
 130 {
 131         return 0;
 132 }
 133
 134 /**
 135  * \fn void FIFO_Close(vfs_node *Node)
 136  */
 137 void FIFO_Close(tVFS_Node *Node)
 138 {
 139         tPipe   *pipe;
 140         if(!Node->ImplPtr)      return ;
 141
 142         Node->ReferenceCount --;
 143         if(Node->ReferenceCount)        return ;
 144
 145         pipe = Node->ImplPtr;
 146
 147         if(strcmp(pipe->Name, "anon") == 0) {
 148                 free(Node->ImplPtr);
 149                 return ;
 150         }
 151
 152         return ;
 153 }
 154
 155 /**
 156  * \fn int FIFO_Relink(tVFS_Node *Node, char *OldName, char *NewName)
 157  * \brief Relink a file (Deletes named pipes)
 158  */
 159 int FIFO_Relink(tVFS_Node *Node, char *OldName, char *NewName)
 160 {
 161         tPipe   *pipe, *tmp;
 162
 163         if(Node != &gFIFO_DriverInfo.RootNode)  return 0;
 164
 165         // Can't relink anon
 166         if(strcmp(OldName, "anon"))     return 0;
 167
 168         // Find node
 169         for(pipe = gFIFO_NamedPipes;
 170                 pipe;
 171                 pipe = pipe->Next)
 172         {
 173                 if(strcmp(pipe->Name, OldName) == 0)
 174                         break;
 175         }
 176         if(!pipe)       return 0;
 177
 178         // Relink a named pipe
 179         if(NewName) {
 180                 // Check new name
 181                 for(tmp = gFIFO_NamedPipes;
 182                         tmp;
 183                         tmp = tmp->Next)
 184                 {
 185                         if(strcmp(tmp->Name, NewName) == 0)     return 0;
 186                 }
 187                 // Create new name
 188                 free(pipe->Name);
 189                 pipe->Name = malloc(strlen(NewName)+1);
 190                 strcpy(pipe->Name, NewName);
 191                 return 1;
 192         }
 193
 194         // Unlink the pipe
 195         if(Node->ImplPtr) {
 196                 free(Node->ImplPtr);
 197                 return 1;
 198         }
 199
 200         return 0;
 201 }
 202
 203 /**
 204  * \fn Uint64 FIFO_Read(tVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer)
 205  * \brief Read from a fifo pipe
 206  */
 207 Uint64 FIFO_Read(tVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer)
 208 {
 209         tPipe   *pipe = Node->ImplPtr;
 210         Uint    len;
 211         Uint    remaining = Length;
 212
 213         if(!pipe)       return 0;
 214
 215         while(remaining)
 216         {
 217                 // Wait for buffer to fill
 218                 if(pipe->Flags & PF_BLOCKING)
 219                         while(pipe->ReadPos == pipe->WritePos)
 220                                 Threads_Yield();
 221                 else
 222                         if(pipe->ReadPos == pipe->WritePos)
 223                                 return 0;
 224
 225                 // Read buffer
 226                 if(pipe->WritePos - pipe->ReadPos < remaining)
 227                         len = pipe->WritePos - pipe->ReadPos;
 228                 else
 229                         len = remaining;
 230
 231                 // Check if read overflows buffer
 232                 if(len > pipe->BufSize - pipe->ReadPos)
 233                 {
 234                         int ofs = pipe->BufSize - pipe->ReadPos;
 235                         memcpy(Buffer, &pipe->Buffer[pipe->ReadPos], ofs);
 236                         memcpy(Buffer + ofs, &pipe->Buffer, len-ofs);
 237                 }
 238                 else
 239                 {
 240                         memcpy(Buffer, &pipe->Buffer[pipe->ReadPos], len);
 241                 }
 242
 243                 // Increment read position
 244                 pipe->ReadPos += len;
 245                 pipe->ReadPos %= pipe->BufSize;
 246
 247                 // Decrement Remaining Bytes
 248                 remaining -= len;
 249                 // Increment Buffer address
 250                 Buffer += len;
 251         }
 252
 253         return Length;
 254
 255 }
 256
 257 /**
 258  * \fn Uint64 FIFO_Write(tVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer)
 259  * \brief Write to a fifo pipe
 260  */
 261 Uint64 FIFO_Write(tVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer)
 262 {
 263         tPipe   *pipe = Node->ImplPtr;
 264         Uint    len;
 265         Uint    remaining = Length;
 266
 267         if(!pipe)       return 0;
 268
 269         while(remaining)
 270         {
 271                 // Wait for buffer to empty
 272                 if(pipe->Flags & PF_BLOCKING)
 273                         while(pipe->ReadPos == (pipe->WritePos+1)%pipe->BufSize)
 274                                 Threads_Yield();
 275                 else
 276                         if(pipe->ReadPos == (pipe->WritePos+1)%pipe->BufSize)
 277                                 return 0;
 278
 279                 // Write buffer
 280                 if(pipe->ReadPos - pipe->WritePos < remaining)
 281                         len = pipe->ReadPos - pipe->WritePos;
 282                 else
 283                         len = remaining;
 284
 285                 // Check if write overflows buffer
 286                 if(len > pipe->BufSize - pipe->WritePos)
 287                 {
 288                         int ofs = pipe->BufSize - pipe->WritePos;
 289                         memcpy(&pipe->Buffer[pipe->WritePos], Buffer, ofs);
 290                         memcpy(&pipe->Buffer, Buffer + ofs, len-ofs);
 291                 }
 292                 else
 293                 {
 294                         memcpy(&pipe->Buffer[pipe->WritePos], Buffer, len);
 295                 }
 296
 297                 // Increment read position
 298                 pipe->WritePos += len;
 299                 pipe->WritePos %= pipe->BufSize;
 300
 301                 // Decrement Remaining Bytes
 302                 remaining -= len;
 303                 // Increment Buffer address
 304                 Buffer += len;
 305         }
 306
 307         return Length;
 308 }
 309
 310 // --- HELPERS ---
 311 /**
 312  * \fn tPipe *FIFO_Int_NewPipe(int Size, char *Name)
 313  * \brief Create a new pipe
 314  */
 315 tPipe *FIFO_Int_NewPipe(int Size, char *Name)
 316 {
 317         tPipe   *ret;
 318          int    allocsize = sizeof(tPipe) + sizeof(tVFS_ACL) + Size;
 319
 320         ret = malloc(allocsize);
 321         if(!ret)        return NULL;
 322
 323         // Clear Return
 324         memset(ret, 0, allocsize);
 325
 326         ret->Name = Name;
 327
 328         // Allocate Buffer
 329         ret->BufSize = Size;
 330         ret->Buffer = (void*)( (Uint)ret + sizeof(tPipe) + sizeof(tVFS_ACL) );
 331         if(!ret->Buffer) {
 332                 free(ret);
 333                 return NULL;
 334         }
 335
 336         // Set Node
 337         ret->Node.Size = 0;
 338         ret->Node.ImplPtr = ret;
 339         ret->Node.UID = Threads_GetUID();
 340         ret->Node.GID = Threads_GetGID();
 341         ret->Node.NumACLs = 1;
 342         ret->Node.ACLs = (void*)( (Uint)ret + sizeof(tPipe) );
 343                 ret->Node.ACLs->Group = 0;
 344                 ret->Node.ACLs->ID = ret->Node.UID;
 345                 ret->Node.ACLs->Inv = 0;
 346                 ret->Node.ACLs->Perms = -1;
 347         ret->Node.CTime
 348                 = ret->Node.MTime
 349                 = ret->Node.ATime = now();
 350         ret->Node.Read = FIFO_Read;
 351         ret->Node.Write = FIFO_Write;
 352         ret->Node.Close = FIFO_Close;
 353
 354         return ret;
 355 }