Kernel/vfs/open.c

   1 /*
   2  * AcessMicro VFS
   3  * - Open, Close and ChDir
   4  */
   5 #include <common.h>
   6 #include "vfs.h"
   7 #include "vfs_int.h"
   8 #include "vfs_ext.h"
   9
  10 #define DEBUG   0
  11
  12 #if DEBUG
  13 #else
  14 # undef ENTER
  15 # undef LOG
  16 # undef LEAVE
  17 # define ENTER(...)
  18 # define LOG(...)
  19 # define LEAVE(...)
  20 #endif
  21
  22 // === CONSTANTS ===
  23 #define OPEN_MOUNT_ROOT 1
  24 #define MAX_KERNEL_FILES        128
  25
  26 // === IMPORTS ===
  27 extern tVFS_Node        gVFS_MemRoot;
  28 extern tVFS_Mount       *gRootMount;
  29
  30 // === GLOBALS ===
  31 tVFS_Handle     *gaUserHandles = (void*)MM_PPD_VFS;
  32 tVFS_Handle     *gaKernelHandles = (void*)MM_KERNEL_VFS;
  33
  34 // === CODE ===
  35 /**
  36  * \fn char *VFS_GetAbsPath(char *Path)
  37  * \brief Create an absolute path from a relative one
  38  */
  39 char *VFS_GetAbsPath(char *Path)
  40 {
  41         char    *ret;
  42          int    pathLen = strlen(Path);
  43          int    read, write;
  44          int    pos, slashNum=0, baseLen;
  45         Uint    slashOffsets[256];
  46         char    *cwd = CFGPTR(CFG_VFS_CWD);
  47          int    cwdLen;
  48
  49         ENTER("sPath", Path);
  50
  51         // Memory File
  52         if(Path[0] == '$') {
  53                 ret = malloc(strlen(Path)+1);
  54                 if(!ret) {
  55                         Warning("VFS_GetAbsPath - malloc() returned NULL");
  56                         return NULL;
  57                 }
  58                 strcpy(ret, Path);
  59                 LEAVE('p', ret);
  60                 return ret;
  61         }
  62
  63         // Check if the path is already absolute
  64         if(Path[0] == '/') {
  65                 ret = malloc(pathLen + 1);
  66                 if(!ret) {
  67                         Warning("VFS_GetAbsPath - malloc() returned NULL");
  68                         return NULL;
  69                 }
  70                 strcpy(ret, Path);
  71                 baseLen = 1;
  72         } else {
  73                 cwdLen = strlen(cwd);
  74                 // Prepend the current directory
  75                 ret = malloc(cwdLen+pathLen+1);
  76                 strcpy(ret, cwd);
  77                 strcpy(&ret[cwdLen], Path);
  78
  79                 // Pre-fill the slash positions
  80                 pos = 0;
  81                 while( (pos = strpos( &ret[pos+1], '/' )) != -1 )
  82                         slashOffsets[slashNum++] = pos;
  83
  84                 baseLen = cwdLen;
  85         }
  86
  87         // Remove . and ..
  88         read = write = baseLen; // Cwd has already been parsed
  89         for(; read < baseLen+pathLen; read = pos+1)
  90         {
  91                 pos = strpos( &ret[read], '/' );
  92                 // If we are in the last section, force a break at the end of the itteration
  93                 if(pos == -1)   pos = baseLen+pathLen;
  94                 else    pos += read;    // Else, Adjust to absolute
  95
  96                 // Check Length
  97                 if(pos - read <= 2)
  98                 {
  99                         // Current Dir "."
 100                         if(strncmp(&ret[read], ".", pos-read) == 0)     continue;
 101                         // Parent ".."
 102                         if(strncmp(&ret[read], "..", pos-read) == 0)
 103                         {
 104                                 // If there is no higher, silently ignore
 105                                 if(!slashNum)   continue;
 106                                 // Reverse write pointer
 107                                 write = slashOffsets[ slashNum-- ];
 108                                 continue;
 109                         }
 110                 }
 111
 112
 113                 // Only copy if the positions differ
 114                 if(read != write) {
 115                         memcpy( &ret[write], &ret[read], pos-read+1 );
 116                 }
 117                 write = pos+1;
 118                 if(slashNum < 256)
 119                         slashOffsets[ slashNum++ ] = pos;
 120                 else {
 121                         LOG("Path '%s' has too many elements", Path);
 122                         free(ret);
 123                         LEAVE('n');
 124                         return NULL;
 125                 }
 126         }
 127
 128         // `ret` should now be the absolute path
 129         LEAVE('s', ret);
 130         return ret;
 131 }
 132
 133 /**
 134  * \fn char *VFS_ParsePath(char *Path, char **TruePath)
 135  * \brief Parses a path, resolving sysmlinks and applying permissions
 136  */
 137 tVFS_Node *VFS_ParsePath(char *Path, char **TruePath)
 138 {
 139         tVFS_Mount      *mnt;
 140         tVFS_Mount      *longestMount = gRootMount;     // Root is first
 141          int    cmp, retLength = 0;
 142          int    ofs, nextSlash;
 143         tVFS_Node       *curNode, *tmpNode;
 144         char    *tmp;
 145
 146         ENTER("sPath pTruePath", Path, TruePath);
 147
 148         // Memory File
 149         if(Path[0] == '$') {
 150                 if(TruePath) {
 151                         *TruePath = malloc(strlen(Path)+1);
 152                         strcpy(*TruePath, Path);
 153                 }
 154                 curNode = gVFS_MemRoot.FindDir(&gVFS_MemRoot, Path);
 155                 LEAVE('p', curNode);
 156                 return curNode;
 157         }
 158         // For root we always fast return
 159
 160         if(Path[0] == '/' && Path[1] == '\0') {
 161                 if(TruePath) {
 162                         *TruePath = malloc( gRootMount->MountPointLen+1 );
 163                         strcpy(*TruePath, gRootMount->MountPoint);
 164                 }
 165                 LEAVE('p', gRootMount->RootNode);
 166                 return gRootMount->RootNode;
 167         }
 168
 169         // Check if there is anything mounted
 170         if(!gMounts)    return NULL;
 171
 172         // Find Mountpoint
 173         for(mnt = gMounts;
 174                 mnt;
 175                 mnt = mnt->Next)
 176         {
 177                 // Quick Check
 178                 if( Path[mnt->MountPointLen] != '/' && Path[mnt->MountPointLen] != '\0')
 179                         continue;
 180                 // Length Check - If the length is smaller than the longest match sofar
 181                 if(mnt->MountPointLen < longestMount->MountPointLen)    continue;
 182                 // String Compare
 183                 cmp = strcmp(Path, mnt->MountPoint);
 184
 185                 #if OPEN_MOUNT_ROOT
 186                 // Fast Break - Request Mount Root
 187                 if(cmp == 0) {
 188                         if(TruePath) {
 189                                 *TruePath = malloc( mnt->MountPointLen+1 );
 190                                 strcpy(*TruePath, mnt->MountPoint);
 191                         }
 192                         LEAVE('p', mnt->RootNode);
 193                         return mnt->RootNode;
 194                 }
 195                 #endif
 196                 // Not a match, continue
 197                 if(cmp != '/')  continue;
 198                 longestMount = mnt;
 199         }
 200
 201         // Sanity Check
 202         /*if(!longestMount) {
 203                 Log("VFS_GetTruePath - ERROR: No Root Node\n");
 204                 return NULL;
 205         }*/
 206
 207         // Save to shorter variable
 208         mnt = longestMount;
 209
 210         LOG("mnt = {MountPoint:\"%s\"}", mnt->MountPoint);
 211
 212         // Initialise String
 213         if(TruePath)
 214         {
 215                 *TruePath = malloc( mnt->MountPointLen+1 );
 216                 strcpy(*TruePath, mnt->MountPoint);
 217                 retLength = mnt->MountPointLen;
 218         }
 219
 220         curNode = mnt->RootNode;
 221         curNode->ReferenceCount ++;
 222         // Parse Path
 223         ofs = mnt->MountPointLen+1;
 224         for(; (nextSlash = strpos(&Path[ofs], '/')) != -1; Path[nextSlash]='/',ofs = nextSlash + 1)
 225         {
 226                 nextSlash += ofs;
 227                 Path[nextSlash] = '\0';
 228
 229                 // Check for empty string
 230                 if( Path[ofs] == '\0' ) continue;
 231
 232                 // Check permissions on root of filesystem
 233                 if( !VFS_CheckACL(curNode, VFS_PERM_EXECUTE) ) {
 234                         curNode->Close( curNode );
 235                         if(TruePath) {
 236                                 free(*TruePath);
 237                                 *TruePath = NULL;
 238                         }
 239                         LEAVE('n');
 240                         return NULL;
 241                 }
 242
 243                 // Check if the node has a FindDir method
 244                 if(!curNode->FindDir) {
 245                         if(curNode->Close)      curNode->Close(curNode);
 246                         if(TruePath) {
 247                                 free(*TruePath);
 248                                 *TruePath = NULL;
 249                         }
 250                         Path[nextSlash] = '/';
 251                         LEAVE('n');
 252                         return NULL;
 253                 }
 254                 LOG("FindDir(%p, '%s')", curNode, &Path[ofs]);
 255                 // Get Child Node
 256                 tmpNode = curNode->FindDir(curNode, &Path[ofs]);
 257                 LOG("tmpNode = %p", tmpNode);
 258                 if(curNode->Close)
 259                         curNode->Close(curNode);
 260                 curNode = tmpNode;
 261
 262                 // Error Check
 263                 if(!curNode) {
 264                         LOG("Node '%s' not found in dir '%s'", &Path[ofs], Path);
 265                         if(TruePath) {
 266                                 free(*TruePath);
 267                                 *TruePath = NULL;
 268                         }
 269                         Path[nextSlash] = '/';
 270                         LEAVE('n');
 271                         return NULL;
 272                 }
 273
 274                 // Handle Symbolic Links
 275                 if(curNode->Flags & VFS_FFLAG_SYMLINK) {
 276                         if(TruePath) {
 277                                 free(*TruePath);
 278                                 *TruePath = NULL;
 279                         }
 280                         tmp = malloc( curNode->Size + 1 );
 281                         curNode->Read( curNode, 0, curNode->Size, tmp );
 282                         tmp[ curNode->Size ] = '\0';
 283
 284                         // Parse Symlink Path
 285                         curNode = VFS_ParsePath(tmp, TruePath);
 286
 287                         // Error Check
 288                         if(!curNode) {
 289                                 free(tmp);      // Free temp string
 290                                 LEAVE('n');
 291                                 return NULL;
 292                         }
 293
 294                         // Set Path Variable
 295                         if(TruePath) {
 296                                 *TruePath = tmp;
 297                                 retLength = strlen(tmp);
 298                         } else {
 299                                 free(tmp);      // Free temp string
 300                         }
 301
 302                         continue;
 303                 }
 304
 305                 // Handle Non-Directories
 306                 if( !(curNode->Flags & VFS_FFLAG_DIRECTORY) )
 307                 {
 308                         Warning("VFS_ParsePath - File in directory context");
 309                         if(TruePath)    free(*TruePath);
 310                         LEAVE('n');
 311                         return NULL;
 312                 }
 313
 314                 // Check if path needs extending
 315                 if(!TruePath)   continue;
 316
 317                 // Increase buffer space
 318                 tmp = realloc( *TruePath, retLength + strlen(&Path[ofs]) + 1 + 1 );
 319                 // Check if allocation succeeded
 320                 if(!tmp) {
 321                         Warning("VFS_ParsePath -  Unable to reallocate true path buffer");
 322                         free(*TruePath);
 323                         if(curNode->Close)      curNode->Close(curNode);
 324                         LEAVE('n');
 325                         return NULL;
 326                 }
 327                 *TruePath = tmp;
 328                 // Append to path
 329                 (*TruePath)[retLength] = '/';
 330                 strcpy(*TruePath+retLength+1, &Path[ofs]);
 331                 // - Extend Path
 332                 retLength += strlen(&Path[ofs])+1;
 333         }
 334
 335         // Get last node
 336         LOG("VFS_ParsePath: FindDir(%p, '%s')", curNode, &Path[ofs]);
 337         tmpNode = curNode->FindDir(curNode, &Path[ofs]);
 338         LOG("tmpNode = %p", tmpNode);
 339         if(curNode->Close)      curNode->Close(curNode);
 340         // Check if file was found
 341         if(!tmpNode) {
 342                 LOG("Node '%s' not found in dir '%s'", &Path[ofs], Path);
 343                 if(TruePath)    free(*TruePath);
 344                 if(curNode->Close)      curNode->Close(curNode);
 345                 LEAVE('n');
 346                 return NULL;
 347         }
 348
 349         if(TruePath)
 350         {
 351                 // Increase buffer space
 352                 tmp = realloc(*TruePath, retLength + strlen(&Path[ofs]) + 1 + 1);
 353                 // Check if allocation succeeded
 354                 if(!tmp) {
 355                         Warning("VFS_ParsePath -  Unable to reallocate true path buffer");
 356                         free(*TruePath);
 357                         if(tmpNode->Close)      tmpNode->Close(curNode);
 358                         LEAVE('n');
 359                         return NULL;
 360                 }
 361                 *TruePath = tmp;
 362                 // Append to path
 363                 (*TruePath)[retLength] = '/';
 364                 strcpy(*TruePath + retLength + 1, &Path[ofs]);
 365                 // - Extend Path
 366                 //retLength += strlen(tmpNode->Name) + 1;
 367         }
 368
 369         LEAVE('p', tmpNode);
 370         return tmpNode;
 371 }
 372
 373 /**
 374  * \fn int VFS_Open(char *Path, Uint Mode)
 375  * \brief Open a file
 376  */
 377 int VFS_Open(char *Path, Uint Mode)
 378 {
 379         tVFS_Node       *node;
 380         char    *absPath;
 381          int    i;
 382
 383         ENTER("sPath xMode", Path, Mode);
 384
 385         // Get absolute path
 386         absPath = VFS_GetAbsPath(Path);
 387         LOG("absPath = \"%s\"", absPath);
 388         // Parse path and get mount point
 389         node = VFS_ParsePath(absPath, NULL);
 390         // Free generated path
 391         free(absPath);
 392
 393         if(!node) {
 394                 LOG("Cannot find node");
 395                 LEAVE('i', -1);
 396                 return -1;
 397         }
 398
 399         // Check for symlinks
 400         if( !(Mode & VFS_OPENFLAG_NOLINK) && (node->Flags & VFS_FFLAG_SYMLINK) )
 401         {
 402                 if( !node->Read ) {
 403                         Warning("No read method on symlink");
 404                         LEAVE('i', -1);
 405                         return -1;
 406                 }
 407                 absPath = malloc(node->Size+1); // Allocate Buffer
 408                 node->Read( node, 0, node->Size, absPath );     // Read Path
 409
 410                 absPath[ node->Size ] = '\0';   // End String
 411                 if(node->Close) node->Close( node );    // Close old node
 412                 node = VFS_ParsePath(absPath, NULL);    // Get new node
 413                 free( absPath );        // Free allocated path
 414         }
 415
 416         if(!node) {
 417                 LEAVE('i', -1);
 418                 return -1;
 419         }
 420
 421         i = 0;
 422         i |= (Mode & VFS_OPENFLAG_EXEC) ? VFS_PERM_EXECUTE : 0;
 423         i |= (Mode & VFS_OPENFLAG_READ) ? VFS_PERM_READ : 0;
 424         i |= (Mode & VFS_OPENFLAG_WRITE) ? VFS_PERM_WRITE : 0;
 425
 426         LOG("i = 0b%b", i);
 427
 428         // Permissions Check
 429         if( !VFS_CheckACL(node, i) ) {
 430                 node->Close( node );
 431                 LEAVE('i', -1);
 432                 return -1;
 433         }
 434
 435         // Check for a user open
 436         if(Mode & VFS_OPENFLAG_USER)
 437         {
 438                 // Allocate Buffer
 439                 if( MM_GetPhysAddr( (Uint)gaUserHandles ) == 0 )
 440                 {
 441                         Uint    addr, size;
 442                         size = CFGINT(CFG_VFS_MAXFILES) * sizeof(tVFS_Handle);
 443                         for(addr = 0; addr < size; addr += 0x1000)
 444                                 MM_Allocate( (Uint)gaUserHandles + addr );
 445                         memset( gaUserHandles, 0, size );
 446                 }
 447                 // Get a handle
 448                 for(i=0;i<CFGINT(CFG_VFS_MAXFILES);i++)
 449                 {
 450                         if(gaUserHandles[i].Node)       continue;
 451                         gaUserHandles[i].Node = node;
 452                         gaUserHandles[i].Position = 0;
 453                         gaUserHandles[i].Mode = Mode;
 454                         LEAVE('i', i);
 455                         return i;
 456                 }
 457         }
 458         else
 459         {
 460                 // Allocate space if not already
 461                 if( MM_GetPhysAddr( (Uint)gaKernelHandles ) == 0 )
 462                 {
 463                         Uint    addr, size;
 464                         size = MAX_KERNEL_FILES * sizeof(tVFS_Handle);
 465                         for(addr = 0; addr < size; addr += 0x1000)
 466                                 MM_Allocate( (Uint)gaKernelHandles + addr );
 467                         memset( gaKernelHandles, 0, size );
 468                 }
 469                 // Get a handle
 470                 for(i=0;i<MAX_KERNEL_FILES;i++)
 471                 {
 472                         if(gaKernelHandles[i].Node)     continue;
 473                         gaKernelHandles[i].Node = node;
 474                         gaKernelHandles[i].Position = 0;
 475                         gaKernelHandles[i].Mode = Mode;
 476                         LEAVE('x', i|VFS_KERNEL_FLAG);
 477                         return i|VFS_KERNEL_FLAG;
 478                 }
 479         }
 480
 481         LEAVE('i', -1);
 482         return -1;
 483 }
 484
 485 /**
 486  * \fn void VFS_Close(int FD)
 487  * \brief Closes an open file handle
 488  */
 489 void VFS_Close(int FD)
 490 {
 491         tVFS_Handle     *h;
 492
 493         // Get handle
 494         h = VFS_GetHandle(FD);
 495         if(h == NULL) {
 496                 Warning("Invalid file handle passed to VFS_Close, 0x%x\n", FD);
 497                 return;
 498         }
 499
 500         if(h->Node->Close)
 501                 h->Node->Close( h->Node );
 502
 503         h->Node = NULL;
 504 }
 505
 506 /**
 507  * \fn int VFS_ChDir(char *New)
 508  * \brief Change current working directory
 509  */
 510 int VFS_ChDir(char *New)
 511 {
 512         char    *buf;
 513         tVFS_Node       *node;
 514
 515         // Create Absolute
 516         buf = VFS_GetAbsPath(New);
 517         if(buf == NULL) {
 518                 Log("VFS_ChDir: Path expansion failed");
 519                 return -1;
 520         }
 521
 522         // Check if path is valid
 523         node = VFS_ParsePath(buf, NULL);
 524         if(!node) {
 525                 Log("VFS_ChDir: Path is invalid");
 526                 return -1;
 527         }
 528
 529         // Check if is a directory
 530         if( !(node->Flags & VFS_FFLAG_DIRECTORY) ) {
 531                 Log("VFS_ChDir: Not a directory");
 532                 if(node->Close) node->Close(node);
 533                 return -1;
 534         }
 535         // Close node
 536         if(node->Close) node->Close(node);
 537
 538         // Free old and set new
 539         free( CFGPTR(CFG_VFS_CWD) );
 540         CFGPTR(CFG_VFS_CWD) = buf;
 541
 542         Log("Updated CWD to '%s'", buf);
 543
 544         return 1;
 545 }
 546
 547 /**
 548  * \fn tVFS_Handle *VFS_GetHandle(int FD)
 549  * \brief Gets a pointer to the handle information structure
 550  */
 551 tVFS_Handle *VFS_GetHandle(int FD)
 552 {
 553         tVFS_Handle     *h;
 554
 555         if(FD < 0)      return NULL;
 556
 557         if(FD & VFS_KERNEL_FLAG) {
 558                 FD &= (VFS_KERNEL_FLAG - 1);
 559                 if(FD >= MAX_KERNEL_FILES)      return NULL;
 560                 h = &gaKernelHandles[ FD ];
 561         } else {
 562                 if(FD >= CFGINT(CFG_VFS_MAXFILES))      return NULL;
 563                 h = &gaUserHandles[ FD ];
 564         }
 565
 566         if(h->Node == NULL)     return NULL;
 567         return h;
 568 }