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    *chroot = CFGPTR(CFG_VFS_CHROOT);
  38          int    chrootLen;
  39         char    *cwd = CFGPTR(CFG_VFS_CWD);
  40          int    cwdLen;
  41
  42
  43         ENTER("sPath", Path);
  44
  45         // Memory File
  46         if(Path[0] == '$') {
  47                 ret = malloc(strlen(Path)+1);
  48                 if(!ret) {
  49                         Warning("VFS_GetAbsPath - malloc() returned NULL");
  50                         return NULL;
  51                 }
  52                 strcpy(ret, Path);
  53                 LEAVE('p', ret);
  54                 return ret;
  55         }
  56
  57         if( chroot == NULL ) {
  58                 chroot = "";
  59                 chrootLen = 0;
  60         } else {
  61                 chrootLen = strlen(chroot);
  62         }
  63
  64         // Check if the path is already absolute
  65         if(Path[0] == '/') {
  66                 ret = malloc(chrootLen + pathLen + 1);
  67                 if(!ret) {
  68                         Warning("VFS_GetAbsPath - malloc() returned NULL");
  69                         return NULL;
  70                 }
  71                 strcpy(ret, chroot);
  72                 strcpy(ret+chrootLen, Path);
  73         } else {
  74                 if(cwd == NULL) {
  75                         cwd = "/";
  76                         cwdLen = 1;
  77                 }
  78                 else {
  79                         cwdLen = strlen(cwd);
  80                 }
  81                 // Prepend the current directory
  82                 ret = malloc( cwdLen + 1 + pathLen + 1 );
  83                 strcpy(ret, cwd);
  84                 ret[cwdLen] = '/';
  85                 strcpy(&ret[cwdLen+1], Path);
  86                 //Log("ret = '%s'\n", ret);
  87         }
  88
  89         // Parse Path
  90         pathComps[iPos++] = tmpStr = ret+1;
  91         while(*tmpStr)
  92         {
  93                 if(*tmpStr++ == '/')
  94                 {
  95                         pathComps[iPos++] = tmpStr;
  96                         if(iPos == MAX_PATH_SLASHES) {
  97                                 LOG("Path '%s' has too many elements", Path);
  98                                 free(ret);
  99                                 LEAVE('n');
 100                                 return NULL;
 101                         }
 102                 }
 103         }
 104         pathComps[iPos] = NULL;
 105
 106         // Cleanup
 107         iPos2 = iPos = 0;
 108         while(pathComps[iPos])
 109         {
 110                 tmpStr = pathComps[iPos];
 111                 // Always Increment iPos
 112                 iPos++;
 113                 // ..
 114                 if(tmpStr[0] == '.' && tmpStr[1] == '.' && (tmpStr[2] == '/' || tmpStr[2] == '\0') )
 115                 {
 116                         if(iPos2 != 0)
 117                                 iPos2 --;
 118                         continue;
 119                 }
 120                 // .
 121                 if(tmpStr[0] == '.' && (tmpStr[1] == '/' || tmpStr[1] == '\0') )
 122                 {
 123                         continue;
 124                 }
 125                 // Empty
 126                 if(tmpStr[0] == '/' || tmpStr[0] == '\0')
 127                 {
 128                         continue;
 129                 }
 130
 131                 // Set New Position
 132                 pathComps[iPos2] = tmpStr;
 133                 iPos2++;
 134         }
 135         pathComps[iPos2] = NULL;
 136
 137         // Build New Path
 138         iPos2 = 1;      iPos = 0;
 139         ret[0] = '/';
 140         while(pathComps[iPos])
 141         {
 142                 tmpStr = pathComps[iPos];
 143                 while(*tmpStr && *tmpStr != '/')
 144                 {
 145                         ret[iPos2++] = *tmpStr;
 146                         tmpStr++;
 147                 }
 148                 ret[iPos2++] = '/';
 149                 iPos++;
 150         }
 151         if(iPos2 > 1)
 152                 ret[iPos2-1] = 0;
 153         else
 154                 ret[iPos2] = 0;
 155
 156         LEAVE('s', ret);
 157         //Log("VFS_GetAbsPath: RETURN '%s'", ret);
 158         return ret;
 159 }
 160
 161 /**
 162  * \fn char *VFS_ParsePath(char *Path, char **TruePath)
 163  * \brief Parses a path, resolving sysmlinks and applying permissions
 164  */
 165 tVFS_Node *VFS_ParsePath(char *Path, char **TruePath)
 166 {
 167         tVFS_Mount      *mnt;
 168         tVFS_Mount      *longestMount = gRootMount;     // Root is first
 169          int    cmp, retLength = 0;
 170          int    ofs, nextSlash;
 171         tVFS_Node       *curNode, *tmpNode;
 172         char    *tmp;
 173
 174         ENTER("sPath pTruePath", Path, TruePath);
 175
 176         // Memory File
 177         if(Path[0] == '$') {
 178                 if(TruePath) {
 179                         *TruePath = malloc(strlen(Path)+1);
 180                         strcpy(*TruePath, Path);
 181                 }
 182                 curNode = gVFS_MemRoot.FindDir(&gVFS_MemRoot, Path);
 183                 LEAVE('p', curNode);
 184                 return curNode;
 185         }
 186         // For root we always fast return
 187
 188         if(Path[0] == '/' && Path[1] == '\0') {
 189                 if(TruePath) {
 190                         *TruePath = malloc( gRootMount->MountPointLen+1 );
 191                         strcpy(*TruePath, gRootMount->MountPoint);
 192                 }
 193                 LEAVE('p', gRootMount->RootNode);
 194                 return gRootMount->RootNode;
 195         }
 196
 197         // Check if there is anything mounted
 198         if(!gMounts) {
 199                 Warning("WTF! There's nothing mounted?");
 200                 return NULL;
 201         }
 202
 203         // Find Mountpoint
 204         for(mnt = gMounts;
 205                 mnt;
 206                 mnt = mnt->Next)
 207         {
 208                 // Quick Check
 209                 if( Path[mnt->MountPointLen] != '/' && Path[mnt->MountPointLen] != '\0')
 210                         continue;
 211                 // Length Check - If the length is smaller than the longest match sofar
 212                 if(mnt->MountPointLen < longestMount->MountPointLen)    continue;
 213                 // String Compare
 214                 cmp = strcmp(Path, mnt->MountPoint);
 215
 216                 #if OPEN_MOUNT_ROOT
 217                 // Fast Break - Request Mount Root
 218                 if(cmp == 0) {
 219                         if(TruePath) {
 220                                 *TruePath = malloc( mnt->MountPointLen+1 );
 221                                 strcpy(*TruePath, mnt->MountPoint);
 222                         }
 223                         LEAVE('p', mnt->RootNode);
 224                         return mnt->RootNode;
 225                 }
 226                 #endif
 227                 // Not a match, continue
 228                 if(cmp != '/')  continue;
 229                 longestMount = mnt;
 230         }
 231
 232         // Sanity Check
 233         /*if(!longestMount) {
 234                 Log("VFS_ParsePath - ERROR: No Root Node\n");
 235                 return NULL;
 236         }*/
 237
 238         // Save to shorter variable
 239         mnt = longestMount;
 240
 241         LOG("mnt = {MountPoint:\"%s\"}", mnt->MountPoint);
 242
 243         // Initialise String
 244         if(TruePath)
 245         {
 246                 *TruePath = malloc( mnt->MountPointLen+1 );
 247                 strcpy(*TruePath, mnt->MountPoint);
 248                 retLength = mnt->MountPointLen;
 249         }
 250
 251         curNode = mnt->RootNode;
 252         curNode->ReferenceCount ++;
 253         // Parse Path
 254         ofs = mnt->MountPointLen+1;
 255         for(; (nextSlash = strpos(&Path[ofs], '/')) != -1; Path[nextSlash]='/',ofs = nextSlash + 1)
 256         {
 257                 nextSlash += ofs;
 258                 Path[nextSlash] = '\0';
 259
 260                 // Check for empty string
 261                 if( Path[ofs] == '\0' ) continue;
 262
 263                 // Check permissions on root of filesystem
 264                 if( !VFS_CheckACL(curNode, VFS_PERM_EXECUTE) ) {
 265                         curNode->Close( curNode );
 266                         if(TruePath) {
 267                                 free(*TruePath);
 268                                 *TruePath = NULL;
 269                         }
 270                         //Log("Permissions fail on '%s'", Path);
 271                         LEAVE('n');
 272                         return NULL;
 273                 }
 274
 275                 // Check if the node has a FindDir method
 276                 if(!curNode->FindDir) {
 277                         if(curNode->Close)      curNode->Close(curNode);
 278                         if(TruePath) {
 279                                 free(*TruePath);
 280                                 *TruePath = NULL;
 281                         }
 282                         Path[nextSlash] = '/';
 283                         //Log("FindDir fail on '%s'", Path);
 284                         LEAVE('n');
 285                         return NULL;
 286                 }
 287                 LOG("FindDir(%p, '%s')", curNode, &Path[ofs]);
 288                 // Get Child Node
 289                 tmpNode = curNode->FindDir(curNode, &Path[ofs]);
 290                 LOG("tmpNode = %p", tmpNode);
 291                 if(curNode->Close)
 292                         curNode->Close(curNode);
 293                 curNode = tmpNode;
 294
 295                 // Error Check
 296                 if(!curNode) {
 297                         LOG("Node '%s' not found in dir '%s'", &Path[ofs], Path);
 298                         if(TruePath) {
 299                                 free(*TruePath);
 300                                 *TruePath = NULL;
 301                         }
 302                         //Log("Child fail on '%s' ('%s)", Path, &Path[ofs]);
 303                         Path[nextSlash] = '/';
 304                         LEAVE('n');
 305                         return NULL;
 306                 }
 307
 308                 // Handle Symbolic Links
 309                 if(curNode->Flags & VFS_FFLAG_SYMLINK) {
 310                         if(TruePath) {
 311                                 free(*TruePath);
 312                                 *TruePath = NULL;
 313                         }
 314                         tmp = malloc( curNode->Size + 1 );
 315                         curNode->Read( curNode, 0, curNode->Size, tmp );
 316                         tmp[ curNode->Size ] = '\0';
 317
 318                         // Parse Symlink Path
 319                         curNode = VFS_ParsePath(tmp, TruePath);
 320
 321                         // Error Check
 322                         if(!curNode) {
 323                                 Log("Symlink fail '%s'", tmp);
 324                                 free(tmp);      // Free temp string
 325                                 LEAVE('n');
 326                                 return NULL;
 327                         }
 328
 329                         // Set Path Variable
 330                         if(TruePath) {
 331                                 *TruePath = tmp;
 332                                 retLength = strlen(tmp);
 333                         } else {
 334                                 free(tmp);      // Free temp string
 335                         }
 336
 337                         continue;
 338                 }
 339
 340                 // Handle Non-Directories
 341                 if( !(curNode->Flags & VFS_FFLAG_DIRECTORY) )
 342                 {
 343                         Warning("VFS_ParsePath - File in directory context");
 344                         if(TruePath)    free(*TruePath);
 345                         LEAVE('n');
 346                         return NULL;
 347                 }
 348
 349                 // Check if path needs extending
 350                 if(!TruePath)   continue;
 351
 352                 // Increase buffer space
 353                 tmp = realloc( *TruePath, retLength + strlen(&Path[ofs]) + 1 + 1 );
 354                 // Check if allocation succeeded
 355                 if(!tmp) {
 356                         Warning("VFS_ParsePath -  Unable to reallocate true path buffer");
 357                         free(*TruePath);
 358                         if(curNode->Close)      curNode->Close(curNode);
 359                         LEAVE('n');
 360                         return NULL;
 361                 }
 362                 *TruePath = tmp;
 363                 // Append to path
 364                 (*TruePath)[retLength] = '/';
 365                 strcpy(*TruePath+retLength+1, &Path[ofs]);
 366                 // - Extend Path
 367                 retLength += strlen(&Path[ofs])+1;
 368         }
 369
 370         // Get last node
 371         LOG("VFS_ParsePath: FindDir(%p, '%s')", curNode, &Path[ofs]);
 372         tmpNode = curNode->FindDir(curNode, &Path[ofs]);
 373         LOG("tmpNode = %p", tmpNode);
 374         if(curNode->Close)      curNode->Close(curNode);
 375         // Check if file was found
 376         if(!tmpNode) {
 377                 LOG("Node '%s' not found in dir '%s'", &Path[ofs], Path);
 378                 //Log("Child fail '%s' ('%s')", Path, &Path[ofs]);
 379                 if(TruePath)    free(*TruePath);
 380                 if(curNode->Close)      curNode->Close(curNode);
 381                 LEAVE('n');
 382                 return NULL;
 383         }
 384
 385         if(TruePath)
 386         {
 387                 // Increase buffer space
 388                 tmp = realloc(*TruePath, retLength + strlen(&Path[ofs]) + 1 + 1);
 389                 // Check if allocation succeeded
 390                 if(!tmp) {
 391                         Warning("VFS_ParsePath -  Unable to reallocate true path buffer");
 392                         free(*TruePath);
 393                         if(tmpNode->Close)      tmpNode->Close(curNode);
 394                         LEAVE('n');
 395                         return NULL;
 396                 }
 397                 *TruePath = tmp;
 398                 // Append to path
 399                 (*TruePath)[retLength] = '/';
 400                 strcpy(*TruePath + retLength + 1, &Path[ofs]);
 401                 // - Extend Path
 402                 //retLength += strlen(tmpNode->Name) + 1;
 403         }
 404
 405         LEAVE('p', tmpNode);
 406         return tmpNode;
 407 }
 408
 409 /**
 410  * \fn int VFS_Open(char *Path, Uint Mode)
 411  * \brief Open a file
 412  */
 413 int VFS_Open(char *Path, Uint Mode)
 414 {
 415         tVFS_Node       *node;
 416         char    *absPath;
 417          int    i;
 418
 419         ENTER("sPath xMode", Path, Mode);
 420
 421         // Get absolute path
 422         absPath = VFS_GetAbsPath(Path);
 423         LOG("absPath = \"%s\"", absPath);
 424         // Parse path and get mount point
 425         node = VFS_ParsePath(absPath, NULL);
 426         // Free generated path
 427         free(absPath);
 428
 429         if(!node) {
 430                 LOG("Cannot find node");
 431                 LEAVE('i', -1);
 432                 return -1;
 433         }
 434
 435         // Check for symlinks
 436         if( !(Mode & VFS_OPENFLAG_NOLINK) && (node->Flags & VFS_FFLAG_SYMLINK) )
 437         {
 438                 if( !node->Read ) {
 439                         Warning("No read method on symlink");
 440                         LEAVE('i', -1);
 441                         return -1;
 442                 }
 443                 absPath = malloc(node->Size+1); // Allocate Buffer
 444                 node->Read( node, 0, node->Size, absPath );     // Read Path
 445
 446                 absPath[ node->Size ] = '\0';   // End String
 447                 if(node->Close) node->Close( node );    // Close old node
 448                 node = VFS_ParsePath(absPath, NULL);    // Get new node
 449                 free( absPath );        // Free allocated path
 450         }
 451
 452         if(!node) {
 453                 LOG("Cannot find node");
 454                 LEAVE('i', -1);
 455                 return -1;
 456         }
 457
 458         i = 0;
 459         i |= (Mode & VFS_OPENFLAG_EXEC) ? VFS_PERM_EXECUTE : 0;
 460         i |= (Mode & VFS_OPENFLAG_READ) ? VFS_PERM_READ : 0;
 461         i |= (Mode & VFS_OPENFLAG_WRITE) ? VFS_PERM_WRITE : 0;
 462
 463         LOG("i = 0b%b", i);
 464
 465         // Permissions Check
 466         if( !VFS_CheckACL(node, i) ) {
 467                 node->Close( node );
 468                 Log("VFS_Open: Permissions Failed");
 469                 LEAVE('i', -1);
 470                 return -1;
 471         }
 472
 473         // Check for a user open
 474         if(Mode & VFS_OPENFLAG_USER)
 475         {
 476                 // Allocate Buffer
 477                 if( MM_GetPhysAddr( (Uint)gaUserHandles ) == 0 )
 478                 {
 479                         Uint    addr, size;
 480                         size = CFGINT(CFG_VFS_MAXFILES) * sizeof(tVFS_Handle);
 481                         for(addr = 0; addr < size; addr += 0x1000)
 482                                 MM_Allocate( (Uint)gaUserHandles + addr );
 483                         memset( gaUserHandles, 0, size );
 484                 }
 485                 // Get a handle
 486                 for(i=0;i<CFGINT(CFG_VFS_MAXFILES);i++)
 487                 {
 488                         if(gaUserHandles[i].Node)       continue;
 489                         gaUserHandles[i].Node = node;
 490                         gaUserHandles[i].Position = 0;
 491                         gaUserHandles[i].Mode = Mode;
 492                         LEAVE('i', i);
 493                         return i;
 494                 }
 495         }
 496         else
 497         {
 498                 // Allocate space if not already
 499                 if( MM_GetPhysAddr( (Uint)gaKernelHandles ) == 0 )
 500                 {
 501                         Uint    addr, size;
 502                         size = MAX_KERNEL_FILES * sizeof(tVFS_Handle);
 503                         for(addr = 0; addr < size; addr += 0x1000)
 504                                 MM_Allocate( (Uint)gaKernelHandles + addr );
 505                         memset( gaKernelHandles, 0, size );
 506                 }
 507                 // Get a handle
 508                 for(i=0;i<MAX_KERNEL_FILES;i++)
 509                 {
 510                         if(gaKernelHandles[i].Node)     continue;
 511                         gaKernelHandles[i].Node = node;
 512                         gaKernelHandles[i].Position = 0;
 513                         gaKernelHandles[i].Mode = Mode;
 514                         LEAVE('x', i|VFS_KERNEL_FLAG);
 515                         return i|VFS_KERNEL_FLAG;
 516                 }
 517         }
 518
 519         Log("VFS_Open: Out of handles");
 520         LEAVE('i', -1);
 521         return -1;
 522 }
 523
 524 /**
 525  * \fn void VFS_Close(int FD)
 526  * \brief Closes an open file handle
 527  */
 528 void VFS_Close(int FD)
 529 {
 530         tVFS_Handle     *h;
 531
 532         // Get handle
 533         h = VFS_GetHandle(FD);
 534         if(h == NULL) {
 535                 Warning("Invalid file handle passed to VFS_Close, 0x%x\n", FD);
 536                 return;
 537         }
 538
 539         if(h->Node->Close)
 540                 h->Node->Close( h->Node );
 541
 542         h->Node = NULL;
 543 }
 544
 545 /**
 546  * \fn int VFS_ChDir(char *New)
 547  * \brief Change current working directory
 548  */
 549 int VFS_ChDir(char *New)
 550 {
 551         char    *buf;
 552          int    fd;
 553         tVFS_Handle     *h;
 554
 555         // Create Absolute
 556         buf = VFS_GetAbsPath(New);
 557         if(buf == NULL) {
 558                 Log("VFS_ChDir: Path expansion failed");
 559                 return -1;
 560         }
 561
 562         // Check if path exists
 563         fd = VFS_Open(buf, VFS_OPENFLAG_EXEC);
 564         if(fd == -1) {
 565                 Log("VFS_ChDir: Path is invalid");
 566                 return -1;
 567         }
 568
 569         // Get node so we can check for directory
 570         h = VFS_GetHandle(fd);
 571         if( !(h->Node->Flags & VFS_FFLAG_DIRECTORY) ) {
 572                 Log("VFS_ChDir: Path is not a directory");
 573                 VFS_Close(fd);
 574                 return -1;
 575         }
 576
 577         // Close file
 578         VFS_Close(fd);
 579
 580         // Free old working directory
 581         if( CFGPTR(CFG_VFS_CWD) )
 582                 free( CFGPTR(CFG_VFS_CWD) );
 583         // Set new
 584         CFGPTR(CFG_VFS_CWD) = buf;
 585
 586         Log("Updated CWD to '%s'", buf);
 587
 588         return 1;
 589 }
 590
 591 /**
 592  * \fn int VFS_ChRoot(char *New)
 593  * \brief Change current root directory
 594  */
 595 int VFS_ChRoot(char *New)
 596 {
 597         char    *buf;
 598          int    fd;
 599         tVFS_Handle     *h;
 600
 601         if(New[0] == '/' && New[1] == '\0')
 602                 return 1;       // What a useless thing to ask!
 603
 604         // Create Absolute
 605         buf = VFS_GetAbsPath(New);
 606         if(buf == NULL) {
 607                 LOG("Path expansion failed");
 608                 return -1;
 609         }
 610
 611         // Check if path exists
 612         fd = VFS_Open(buf, VFS_OPENFLAG_EXEC);
 613         if(fd == -1) {
 614                 LOG("Path is invalid");
 615                 return -1;
 616         }
 617
 618         // Get node so we can check for directory
 619         h = VFS_GetHandle(fd);
 620         if( !(h->Node->Flags & VFS_FFLAG_DIRECTORY) ) {
 621                 LOG("Path is not a directory");
 622                 VFS_Close(fd);
 623                 return -1;
 624         }
 625
 626         // Close file
 627         VFS_Close(fd);
 628
 629         // Free old working directory
 630         if( CFGPTR(CFG_VFS_CHROOT) )
 631                 free( CFGPTR(CFG_VFS_CHROOT) );
 632         // Set new
 633         CFGPTR(CFG_VFS_CHROOT) = buf;
 634
 635         LOG("Updated Root to '%s'", buf);
 636
 637         return 1;
 638 }
 639
 640 /**
 641  * \fn tVFS_Handle *VFS_GetHandle(int FD)
 642  * \brief Gets a pointer to the handle information structure
 643  */
 644 tVFS_Handle *VFS_GetHandle(int FD)
 645 {
 646         tVFS_Handle     *h;
 647
 648         if(FD < 0)      return NULL;
 649
 650         if(FD & VFS_KERNEL_FLAG) {
 651                 FD &= (VFS_KERNEL_FLAG - 1);
 652                 if(FD >= MAX_KERNEL_FILES)      return NULL;
 653                 h = &gaKernelHandles[ FD ];
 654         } else {
 655                 if(FD >= CFGINT(CFG_VFS_MAXFILES))      return NULL;
 656                 h = &gaUserHandles[ FD ];
 657         }
 658
 659         if(h->Node == NULL)     return NULL;
 660         return h;
 661 }