Kernel/vfs/open.c

   1 /*
   2  * AcessMicro VFS
   3  * - Open, Close and ChDir
   4  */
   5 #define DEBUG   0
   6 #include <common.h>
   7 #include "vfs.h"
   8 #include "vfs_int.h"
   9 #include "vfs_ext.h"
  10
  11 // === CONSTANTS ===
  12 #define OPEN_MOUNT_ROOT 1
  13 #define MAX_KERNEL_FILES        128
  14 #define MAX_PATH_SLASHES        256
  15
  16 // === IMPORTS ===
  17 extern tVFS_Node        gVFS_MemRoot;
  18 extern tVFS_Mount       *gRootMount;
  19
  20 // === GLOBALS ===
  21 tVFS_Handle     *gaUserHandles = (void*)MM_PPD_VFS;
  22 tVFS_Handle     *gaKernelHandles = (void*)MM_KERNEL_VFS;
  23
  24 // === CODE ===
  25 /**
  26  * \fn char *VFS_GetAbsPath(char *Path)
  27  * \brief Create an absolute path from a relative one
  28  */
  29 char *VFS_GetAbsPath(char *Path)
  30 {
  31         char    *ret;
  32          int    pathLen = strlen(Path);
  33         char    *pathComps[MAX_PATH_SLASHES];
  34         char    *tmpStr;
  35         int             iPos = 0;
  36         int             iPos2 = 0;
  37         char    *cwd = CFGPTR(CFG_VFS_CWD);
  38          int    cwdLen;
  39
  40
  41         ENTER("sPath", Path);
  42
  43         // Memory File
  44         if(Path[0] == '$') {
  45                 ret = malloc(strlen(Path)+1);
  46                 if(!ret) {
  47                         Warning("VFS_GetAbsPath - malloc() returned NULL");
  48                         return NULL;
  49                 }
  50                 strcpy(ret, Path);
  51                 LEAVE('p', ret);
  52                 return ret;
  53         }
  54
  55         // Check if the path is already absolute
  56         if(Path[0] == '/') {
  57                 ret = malloc(pathLen + 1);
  58                 if(!ret) {
  59                         Warning("VFS_GetAbsPath - malloc() returned NULL");
  60                         return NULL;
  61                 }
  62                 strcpy(ret, Path);
  63         } else {
  64                 if(cwd == NULL) {
  65                         cwd = "/";
  66                         cwdLen = 1;
  67                 }
  68                 else {
  69                         cwdLen = strlen(cwd);
  70                 }
  71                 // Prepend the current directory
  72                 ret = malloc( cwdLen + 1 + pathLen + 1 );
  73                 strcpy(ret, cwd);
  74                 ret[cwdLen] = '/';
  75                 strcpy(&ret[cwdLen+1], Path);
  76         }
  77
  78         // Parse Path
  79         pathComps[iPos++] = tmpStr = ret+1;
  80         while(*tmpStr)
  81         {
  82                 if(*tmpStr++ == '/')
  83                 {
  84                         pathComps[iPos++] = tmpStr;
  85                         if(iPos == MAX_PATH_SLASHES) {
  86                                 LOG("Path '%s' has too many elements", Path);
  87                                 free(ret);
  88                                 LEAVE('n');
  89                                 return NULL;
  90                         }
  91                 }
  92         }
  93         pathComps[iPos] = NULL;
  94
  95         // Cleanup
  96         iPos2 = iPos = 0;
  97         while(pathComps[iPos])
  98         {
  99                 tmpStr = pathComps[iPos];
 100                 // Always Increment iPos
 101                 iPos++;
 102                 // ..
 103                 if(tmpStr[0] == '.' && tmpStr[1] == '.' && (tmpStr[2] == '/' || tmpStr[2] == '\0') )
 104                 {
 105                         if(iPos2 != 0)
 106                                 iPos2 --;
 107                         continue;
 108                 }
 109                 // .
 110                 if(tmpStr[0] == '.' && (tmpStr[1] == '/' || tmpStr[1] == '\0') )
 111                 {
 112                         continue;
 113                 }
 114                 // Empty
 115                 if(tmpStr[0] == '/' || tmpStr[0] == '\0')
 116                 {
 117                         continue;
 118                 }
 119
 120                 // Set New Position
 121                 pathComps[iPos2] = tmpStr;
 122                 iPos2++;
 123         }
 124         pathComps[iPos2] = NULL;
 125
 126         // Build New Path
 127         iPos2 = 1;      iPos = 0;
 128         ret[0] = '/';
 129         while(pathComps[iPos])
 130         {
 131                 tmpStr = pathComps[iPos];
 132                 while(*tmpStr && *tmpStr != '/')
 133                 {
 134                         ret[iPos2++] = *tmpStr;
 135                         tmpStr++;
 136                 }
 137                 ret[iPos2++] = '/';
 138                 iPos++;
 139         }
 140         if(iPos2 > 1)
 141                 ret[iPos2-1] = 0;
 142         else
 143                 ret[iPos2] = 0;
 144
 145         LEAVE('s', ret);
 146         Log("VFS_GetAbsPath: RETURN '%s'", ret);
 147         return ret;
 148 }
 149
 150 /**
 151  * \fn char *VFS_ParsePath(char *Path, char **TruePath)
 152  * \brief Parses a path, resolving sysmlinks and applying permissions
 153  */
 154 tVFS_Node *VFS_ParsePath(char *Path, char **TruePath)
 155 {
 156         tVFS_Mount      *mnt;
 157         tVFS_Mount      *longestMount = gRootMount;     // Root is first
 158          int    cmp, retLength = 0;
 159          int    ofs, nextSlash;
 160         tVFS_Node       *curNode, *tmpNode;
 161         char    *tmp;
 162
 163         ENTER("sPath pTruePath", Path, TruePath);
 164
 165         // Memory File
 166         if(Path[0] == '$') {
 167                 if(TruePath) {
 168                         *TruePath = malloc(strlen(Path)+1);
 169                         strcpy(*TruePath, Path);
 170                 }
 171                 curNode = gVFS_MemRoot.FindDir(&gVFS_MemRoot, Path);
 172                 LEAVE('p', curNode);
 173                 return curNode;
 174         }
 175         // For root we always fast return
 176
 177         if(Path[0] == '/' && Path[1] == '\0') {
 178                 if(TruePath) {
 179                         *TruePath = malloc( gRootMount->MountPointLen+1 );
 180                         strcpy(*TruePath, gRootMount->MountPoint);
 181                 }
 182                 LEAVE('p', gRootMount->RootNode);
 183                 return gRootMount->RootNode;
 184         }
 185
 186         // Check if there is anything mounted
 187         if(!gMounts) {
 188                 Warning("WTF! There's nothing mounted?");
 189                 return NULL;
 190         }
 191
 192         // Find Mountpoint
 193         for(mnt = gMounts;
 194                 mnt;
 195                 mnt = mnt->Next)
 196         {
 197                 // Quick Check
 198                 if( Path[mnt->MountPointLen] != '/' && Path[mnt->MountPointLen] != '\0')
 199                         continue;
 200                 // Length Check - If the length is smaller than the longest match sofar
 201                 if(mnt->MountPointLen < longestMount->MountPointLen)    continue;
 202                 // String Compare
 203                 cmp = strcmp(Path, mnt->MountPoint);
 204
 205                 #if OPEN_MOUNT_ROOT
 206                 // Fast Break - Request Mount Root
 207                 if(cmp == 0) {
 208                         if(TruePath) {
 209                                 *TruePath = malloc( mnt->MountPointLen+1 );
 210                                 strcpy(*TruePath, mnt->MountPoint);
 211                         }
 212                         LEAVE('p', mnt->RootNode);
 213                         return mnt->RootNode;
 214                 }
 215                 #endif
 216                 // Not a match, continue
 217                 if(cmp != '/')  continue;
 218                 longestMount = mnt;
 219         }
 220
 221         // Sanity Check
 222         /*if(!longestMount) {
 223                 Log("VFS_GetTruePath - ERROR: No Root Node\n");
 224                 return NULL;
 225         }*/
 226
 227         // Save to shorter variable
 228         mnt = longestMount;
 229
 230         LOG("mnt = {MountPoint:\"%s\"}", mnt->MountPoint);
 231
 232         // Initialise String
 233         if(TruePath)
 234         {
 235                 *TruePath = malloc( mnt->MountPointLen+1 );
 236                 strcpy(*TruePath, mnt->MountPoint);
 237                 retLength = mnt->MountPointLen;
 238         }
 239
 240         curNode = mnt->RootNode;
 241         curNode->ReferenceCount ++;
 242         // Parse Path
 243         ofs = mnt->MountPointLen+1;
 244         for(; (nextSlash = strpos(&Path[ofs], '/')) != -1; Path[nextSlash]='/',ofs = nextSlash + 1)
 245         {
 246                 nextSlash += ofs;
 247                 Path[nextSlash] = '\0';
 248
 249                 // Check for empty string
 250                 if( Path[ofs] == '\0' ) continue;
 251
 252                 // Check permissions on root of filesystem
 253                 if( !VFS_CheckACL(curNode, VFS_PERM_EXECUTE) ) {
 254                         curNode->Close( curNode );
 255                         if(TruePath) {
 256                                 free(*TruePath);
 257                                 *TruePath = NULL;
 258                         }
 259                         Log("Permissions fail on '%s'", Path);
 260                         LEAVE('n');
 261                         return NULL;
 262                 }
 263
 264                 // Check if the node has a FindDir method
 265                 if(!curNode->FindDir) {
 266                         if(curNode->Close)      curNode->Close(curNode);
 267                         if(TruePath) {
 268                                 free(*TruePath);
 269                                 *TruePath = NULL;
 270                         }
 271                         Path[nextSlash] = '/';
 272                         Log("FindDir fail on '%s'", Path);
 273                         LEAVE('n');
 274                         return NULL;
 275                 }
 276                 LOG("FindDir(%p, '%s')", curNode, &Path[ofs]);
 277                 // Get Child Node
 278                 tmpNode = curNode->FindDir(curNode, &Path[ofs]);
 279                 LOG("tmpNode = %p", tmpNode);
 280                 if(curNode->Close)
 281                         curNode->Close(curNode);
 282                 curNode = tmpNode;
 283
 284                 // Error Check
 285                 if(!curNode) {
 286                         LOG("Node '%s' not found in dir '%s'", &Path[ofs], Path);
 287                         if(TruePath) {
 288                                 free(*TruePath);
 289                                 *TruePath = NULL;
 290                         }
 291                         Log("Child fail on '%s' ('%s)", Path, &Path[ofs]);
 292                         Path[nextSlash] = '/';
 293                         LEAVE('n');
 294                         return NULL;
 295                 }
 296
 297                 // Handle Symbolic Links
 298                 if(curNode->Flags & VFS_FFLAG_SYMLINK) {
 299                         if(TruePath) {
 300                                 free(*TruePath);
 301                                 *TruePath = NULL;
 302                         }
 303                         tmp = malloc( curNode->Size + 1 );
 304                         curNode->Read( curNode, 0, curNode->Size, tmp );
 305                         tmp[ curNode->Size ] = '\0';
 306
 307                         // Parse Symlink Path
 308                         curNode = VFS_ParsePath(tmp, TruePath);
 309
 310                         // Error Check
 311                         if(!curNode) {
 312                                 Log("Symlink fail '%s'", tmp);
 313                                 free(tmp);      // Free temp string
 314                                 LEAVE('n');
 315                                 return NULL;
 316                         }
 317
 318                         // Set Path Variable
 319                         if(TruePath) {
 320                                 *TruePath = tmp;
 321                                 retLength = strlen(tmp);
 322                         } else {
 323                                 free(tmp);      // Free temp string
 324                         }
 325
 326                         continue;
 327                 }
 328
 329                 // Handle Non-Directories
 330                 if( !(curNode->Flags & VFS_FFLAG_DIRECTORY) )
 331                 {
 332                         Warning("VFS_ParsePath - File in directory context");
 333                         if(TruePath)    free(*TruePath);
 334                         LEAVE('n');
 335                         return NULL;
 336                 }
 337
 338                 // Check if path needs extending
 339                 if(!TruePath)   continue;
 340
 341                 // Increase buffer space
 342                 tmp = realloc( *TruePath, retLength + strlen(&Path[ofs]) + 1 + 1 );
 343                 // Check if allocation succeeded
 344                 if(!tmp) {
 345                         Warning("VFS_ParsePath -  Unable to reallocate true path buffer");
 346                         free(*TruePath);
 347                         if(curNode->Close)      curNode->Close(curNode);
 348                         LEAVE('n');
 349                         return NULL;
 350                 }
 351                 *TruePath = tmp;
 352                 // Append to path
 353                 (*TruePath)[retLength] = '/';
 354                 strcpy(*TruePath+retLength+1, &Path[ofs]);
 355                 // - Extend Path
 356                 retLength += strlen(&Path[ofs])+1;
 357         }
 358
 359         // Get last node
 360         LOG("VFS_ParsePath: FindDir(%p, '%s')", curNode, &Path[ofs]);
 361         tmpNode = curNode->FindDir(curNode, &Path[ofs]);
 362         LOG("tmpNode = %p", tmpNode);
 363         if(curNode->Close)      curNode->Close(curNode);
 364         // Check if file was found
 365         if(!tmpNode) {
 366                 LOG("Node '%s' not found in dir '%s'", &Path[ofs], Path);
 367                 Log("Child fail '%s' ('%s')", Path, &Path[ofs]);
 368                 if(TruePath)    free(*TruePath);
 369                 if(curNode->Close)      curNode->Close(curNode);
 370                 LEAVE('n');
 371                 return NULL;
 372         }
 373
 374         if(TruePath)
 375         {
 376                 // Increase buffer space
 377                 tmp = realloc(*TruePath, retLength + strlen(&Path[ofs]) + 1 + 1);
 378                 // Check if allocation succeeded
 379                 if(!tmp) {
 380                         Warning("VFS_ParsePath -  Unable to reallocate true path buffer");
 381                         free(*TruePath);
 382                         if(tmpNode->Close)      tmpNode->Close(curNode);
 383                         LEAVE('n');
 384                         return NULL;
 385                 }
 386                 *TruePath = tmp;
 387                 // Append to path
 388                 (*TruePath)[retLength] = '/';
 389                 strcpy(*TruePath + retLength + 1, &Path[ofs]);
 390                 // - Extend Path
 391                 //retLength += strlen(tmpNode->Name) + 1;
 392         }
 393
 394         LEAVE('p', tmpNode);
 395         return tmpNode;
 396 }
 397
 398 /**
 399  * \fn int VFS_Open(char *Path, Uint Mode)
 400  * \brief Open a file
 401  */
 402 int VFS_Open(char *Path, Uint Mode)
 403 {
 404         tVFS_Node       *node;
 405         char    *absPath;
 406          int    i;
 407
 408         ENTER("sPath xMode", Path, Mode);
 409
 410         // Get absolute path
 411         absPath = VFS_GetAbsPath(Path);
 412         LOG("absPath = \"%s\"", absPath);
 413         // Parse path and get mount point
 414         node = VFS_ParsePath(absPath, NULL);
 415         // Free generated path
 416         free(absPath);
 417
 418         if(!node) {
 419                 LOG("Cannot find node");
 420                 LEAVE('i', -1);
 421                 return -1;
 422         }
 423
 424         // Check for symlinks
 425         if( !(Mode & VFS_OPENFLAG_NOLINK) && (node->Flags & VFS_FFLAG_SYMLINK) )
 426         {
 427                 if( !node->Read ) {
 428                         Warning("No read method on symlink");
 429                         LEAVE('i', -1);
 430                         return -1;
 431                 }
 432                 absPath = malloc(node->Size+1); // Allocate Buffer
 433                 node->Read( node, 0, node->Size, absPath );     // Read Path
 434
 435                 absPath[ node->Size ] = '\0';   // End String
 436                 if(node->Close) node->Close( node );    // Close old node
 437                 node = VFS_ParsePath(absPath, NULL);    // Get new node
 438                 free( absPath );        // Free allocated path
 439         }
 440
 441         if(!node) {
 442                 LOG("Cannot find node");
 443                 LEAVE('i', -1);
 444                 return -1;
 445         }
 446
 447         i = 0;
 448         i |= (Mode & VFS_OPENFLAG_EXEC) ? VFS_PERM_EXECUTE : 0;
 449         i |= (Mode & VFS_OPENFLAG_READ) ? VFS_PERM_READ : 0;
 450         i |= (Mode & VFS_OPENFLAG_WRITE) ? VFS_PERM_WRITE : 0;
 451
 452         LOG("i = 0b%b", i);
 453
 454         // Permissions Check
 455         if( !VFS_CheckACL(node, i) ) {
 456                 node->Close( node );
 457                 Log("VFS_Open: Permissions Failed");
 458                 LEAVE('i', -1);
 459                 return -1;
 460         }
 461
 462         // Check for a user open
 463         if(Mode & VFS_OPENFLAG_USER)
 464         {
 465                 // Allocate Buffer
 466                 if( MM_GetPhysAddr( (Uint)gaUserHandles ) == 0 )
 467                 {
 468                         Uint    addr, size;
 469                         Log("Allocating %i user handles", CFGINT(CFG_VFS_MAXFILES));
 470                         size = CFGINT(CFG_VFS_MAXFILES) * sizeof(tVFS_Handle);
 471                         for(addr = 0; addr < size; addr += 0x1000)
 472                                 MM_Allocate( (Uint)gaUserHandles + addr );
 473                         memset( gaUserHandles, 0, size );
 474                 }
 475                 // Get a handle
 476                 for(i=0;i<CFGINT(CFG_VFS_MAXFILES);i++)
 477                 {
 478                         if(gaUserHandles[i].Node)       continue;
 479                         gaUserHandles[i].Node = node;
 480                         gaUserHandles[i].Position = 0;
 481                         gaUserHandles[i].Mode = Mode;
 482                         LEAVE('i', i);
 483                         return i;
 484                 }
 485         }
 486         else
 487         {
 488                 // Allocate space if not already
 489                 if( MM_GetPhysAddr( (Uint)gaKernelHandles ) == 0 )
 490                 {
 491                         Uint    addr, size;
 492                         size = MAX_KERNEL_FILES * sizeof(tVFS_Handle);
 493                         for(addr = 0; addr < size; addr += 0x1000)
 494                                 MM_Allocate( (Uint)gaKernelHandles + addr );
 495                         memset( gaKernelHandles, 0, size );
 496                 }
 497                 // Get a handle
 498                 for(i=0;i<MAX_KERNEL_FILES;i++)
 499                 {
 500                         if(gaKernelHandles[i].Node)     continue;
 501                         gaKernelHandles[i].Node = node;
 502                         gaKernelHandles[i].Position = 0;
 503                         gaKernelHandles[i].Mode = Mode;
 504                         LEAVE('x', i|VFS_KERNEL_FLAG);
 505                         return i|VFS_KERNEL_FLAG;
 506                 }
 507         }
 508
 509         Log("VFS_Open: Out of handles");
 510         LEAVE('i', -1);
 511         return -1;
 512 }
 513
 514 /**
 515  * \fn void VFS_Close(int FD)
 516  * \brief Closes an open file handle
 517  */
 518 void VFS_Close(int FD)
 519 {
 520         tVFS_Handle     *h;
 521
 522         // Get handle
 523         h = VFS_GetHandle(FD);
 524         if(h == NULL) {
 525                 Warning("Invalid file handle passed to VFS_Close, 0x%x\n", FD);
 526                 return;
 527         }
 528
 529         if(h->Node->Close)
 530                 h->Node->Close( h->Node );
 531
 532         h->Node = NULL;
 533 }
 534
 535 /**
 536  * \fn int VFS_ChDir(char *New)
 537  * \brief Change current working directory
 538  */
 539 int VFS_ChDir(char *New)
 540 {
 541         char    *buf;
 542          int    fd;
 543         tVFS_Handle     *h;
 544
 545         // Create Absolute
 546         buf = VFS_GetAbsPath(New);
 547         if(buf == NULL) {
 548                 Log("VFS_ChDir: Path expansion failed");
 549                 return -1;
 550         }
 551
 552         // Check if path exists
 553         fd = VFS_Open(buf, VFS_OPENFLAG_EXEC);
 554         if(fd == -1) {
 555                 Log("VFS_ChDir: Path is invalid");
 556                 return -1;
 557         }
 558
 559         // Get node so we can check for directory
 560         h = VFS_GetHandle(fd);
 561         if( !(h->Node->Flags & VFS_FFLAG_DIRECTORY) ) {
 562                 Log("VFS_ChDir: Path is not a directory");
 563                 VFS_Close(fd);
 564                 return -1;
 565         }
 566
 567         // Close file
 568         VFS_Close(fd);
 569
 570         // Free old working directory
 571         if( CFGPTR(CFG_VFS_CWD) )
 572                 free( CFGPTR(CFG_VFS_CWD) );
 573         // Set new
 574         CFGPTR(CFG_VFS_CWD) = buf;
 575
 576         //Log("Updated CWD to '%s'", buf);
 577
 578         return 1;
 579 }
 580
 581 /**
 582  * \fn tVFS_Handle *VFS_GetHandle(int FD)
 583  * \brief Gets a pointer to the handle information structure
 584  */
 585 tVFS_Handle *VFS_GetHandle(int FD)
 586 {
 587         tVFS_Handle     *h;
 588
 589         if(FD < 0)      return NULL;
 590
 591         if(FD & VFS_KERNEL_FLAG) {
 592                 FD &= (VFS_KERNEL_FLAG - 1);
 593                 if(FD >= MAX_KERNEL_FILES)      return NULL;
 594                 h = &gaKernelHandles[ FD ];
 595         } else {
 596                 if(FD >= CFGINT(CFG_VFS_MAXFILES))      return NULL;
 597                 h = &gaUserHandles[ FD ];
 598         }
 599
 600         if(h->Node == NULL)     return NULL;
 601         return h;
 602 }