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       *gVFS_RootMount;
  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         ENTER("sPath", Path);
  43
  44         // Memory File
  45         if(Path[0] == '$') {
  46                 ret = malloc(strlen(Path)+1);
  47                 if(!ret) {
  48                         Warning("VFS_GetAbsPath - malloc() returned NULL");
  49                         return NULL;
  50                 }
  51                 strcpy(ret, Path);
  52                 LEAVE('p', ret);
  53                 return ret;
  54         }
  55
  56         // - Fetch ChRoot
  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(pathLen + 1);
  67                 if(!ret) {
  68                         Warning("VFS_GetAbsPath - malloc() returned NULL");
  69                         return NULL;
  70                 }
  71                 strcpy(ret, Path);
  72         } else {
  73                 if(cwd == NULL) {
  74                         cwd = "/";
  75                         cwdLen = 1;
  76                 }
  77                 else {
  78                         cwdLen = strlen(cwd);
  79                 }
  80                 // Prepend the current directory
  81                 ret = malloc( cwdLen + 1 + pathLen + 1 );
  82                 strcpy(ret, cwd);
  83                 ret[cwdLen] = '/';
  84                 strcpy(&ret[cwdLen+1], Path);
  85                 //Log("ret = '%s'\n", ret);
  86         }
  87
  88         // Parse Path
  89         pathComps[iPos++] = tmpStr = ret+1;
  90         while(*tmpStr)
  91         {
  92                 if(*tmpStr++ == '/')
  93                 {
  94                         pathComps[iPos++] = tmpStr;
  95                         if(iPos == MAX_PATH_SLASHES) {
  96                                 LOG("Path '%s' has too many elements", Path);
  97                                 free(ret);
  98                                 LEAVE('n');
  99                                 return NULL;
 100                         }
 101                 }
 102         }
 103         pathComps[iPos] = NULL;
 104
 105         // Cleanup
 106         iPos2 = iPos = 0;
 107         while(pathComps[iPos])
 108         {
 109                 tmpStr = pathComps[iPos];
 110                 // Always Increment iPos
 111                 iPos++;
 112                 // ..
 113                 if(tmpStr[0] == '.' && tmpStr[1] == '.' && (tmpStr[2] == '/' || tmpStr[2] == '\0') )
 114                 {
 115                         if(iPos2 != 0)
 116                                 iPos2 --;
 117                         continue;
 118                 }
 119                 // .
 120                 if(tmpStr[0] == '.' && (tmpStr[1] == '/' || tmpStr[1] == '\0') )
 121                 {
 122                         continue;
 123                 }
 124                 // Empty
 125                 if(tmpStr[0] == '/' || tmpStr[0] == '\0')
 126                 {
 127                         continue;
 128                 }
 129
 130                 // Set New Position
 131                 pathComps[iPos2] = tmpStr;
 132                 iPos2++;
 133         }
 134         pathComps[iPos2] = NULL;
 135
 136         // Build New Path
 137         iPos2 = 1;      iPos = 0;
 138         ret[0] = '/';
 139         while(pathComps[iPos])
 140         {
 141                 tmpStr = pathComps[iPos];
 142                 while(*tmpStr && *tmpStr != '/')
 143                 {
 144                         ret[iPos2++] = *tmpStr;
 145                         tmpStr++;
 146                 }
 147                 ret[iPos2++] = '/';
 148                 iPos++;
 149         }
 150         if(iPos2 > 1)
 151                 ret[iPos2-1] = 0;
 152         else
 153                 ret[iPos2] = 0;
 154
 155
 156         // Prepend the chroot
 157         tmpStr = malloc(chrootLen + strlen(ret) + 1);
 158         strcpy( tmpStr, chroot );
 159         strcpy( tmpStr+chrootLen, ret );
 160         free(ret);
 161         ret = tmpStr;
 162
 163         LEAVE('s', ret);
 164         //Log("VFS_GetAbsPath: RETURN '%s'", ret);
 165         return ret;
 166 }
 167
 168 /**
 169  * \fn char *VFS_ParsePath(char *Path, char **TruePath)
 170  * \brief Parses a path, resolving sysmlinks and applying permissions
 171  */
 172 tVFS_Node *VFS_ParsePath(char *Path, char **TruePath)
 173 {
 174         tVFS_Mount      *mnt;
 175         tVFS_Mount      *longestMount = gVFS_RootMount; // Root is first
 176          int    cmp, retLength = 0;
 177          int    ofs, nextSlash;
 178         tVFS_Node       *curNode, *tmpNode;
 179         char    *tmp;
 180
 181         ENTER("sPath pTruePath", Path, TruePath);
 182
 183         // Memory File
 184         if(Path[0] == '$') {
 185                 if(TruePath) {
 186                         *TruePath = malloc(strlen(Path)+1);
 187                         strcpy(*TruePath, Path);
 188                 }
 189                 curNode = gVFS_MemRoot.FindDir(&gVFS_MemRoot, Path);
 190                 LEAVE('p', curNode);
 191                 return curNode;
 192         }
 193         // For root we always fast return
 194
 195         if(Path[0] == '/' && Path[1] == '\0') {
 196                 if(TruePath) {
 197                         *TruePath = malloc( gVFS_RootMount->MountPointLen+1 );
 198                         strcpy(*TruePath, gVFS_RootMount->MountPoint);
 199                 }
 200                 LEAVE('p', gVFS_RootMount->RootNode);
 201                 return gVFS_RootMount->RootNode;
 202         }
 203
 204         // Check if there is anything mounted
 205         if(!gVFS_Mounts) {
 206                 Warning("WTF! There's nothing mounted?");
 207                 return NULL;
 208         }
 209
 210         // Find Mountpoint
 211         for(mnt = gVFS_Mounts;
 212                 mnt;
 213                 mnt = mnt->Next)
 214         {
 215                 // Quick Check
 216                 if( Path[mnt->MountPointLen] != '/' && Path[mnt->MountPointLen] != '\0')
 217                         continue;
 218                 // Length Check - If the length is smaller than the longest match sofar
 219                 if(mnt->MountPointLen < longestMount->MountPointLen)    continue;
 220                 // String Compare
 221                 cmp = strcmp(Path, mnt->MountPoint);
 222
 223                 #if OPEN_MOUNT_ROOT
 224                 // Fast Break - Request Mount Root
 225                 if(cmp == 0) {
 226                         if(TruePath) {
 227                                 *TruePath = malloc( mnt->MountPointLen+1 );
 228                                 strcpy(*TruePath, mnt->MountPoint);
 229                         }
 230                         LEAVE('p', mnt->RootNode);
 231                         return mnt->RootNode;
 232                 }
 233                 #endif
 234                 // Not a match, continue
 235                 if(cmp != '/')  continue;
 236                 longestMount = mnt;
 237         }
 238
 239         // Sanity Check
 240         /*if(!longestMount) {
 241                 Log("VFS_ParsePath - ERROR: No Root Node\n");
 242                 return NULL;
 243         }*/
 244
 245         // Save to shorter variable
 246         mnt = longestMount;
 247
 248         LOG("mnt = {MountPoint:\"%s\"}", mnt->MountPoint);
 249
 250         // Initialise String
 251         if(TruePath)
 252         {
 253                 *TruePath = malloc( mnt->MountPointLen+1 );
 254                 strcpy(*TruePath, mnt->MountPoint);
 255                 retLength = mnt->MountPointLen;
 256         }
 257
 258         curNode = mnt->RootNode;
 259         curNode->ReferenceCount ++;
 260         // Parse Path
 261         ofs = mnt->MountPointLen+1;
 262         for(; (nextSlash = strpos(&Path[ofs], '/')) != -1; Path[nextSlash]='/',ofs = nextSlash + 1)
 263         {
 264                 nextSlash += ofs;
 265                 Path[nextSlash] = '\0';
 266
 267                 // Check for empty string
 268                 if( Path[ofs] == '\0' ) continue;
 269
 270                 // Check permissions on root of filesystem
 271                 if( !VFS_CheckACL(curNode, VFS_PERM_EXECUTE) ) {
 272                         curNode->Close( curNode );
 273                         if(TruePath) {
 274                                 free(*TruePath);
 275                                 *TruePath = NULL;
 276                         }
 277                         //Log("Permissions fail on '%s'", Path);
 278                         LEAVE('n');
 279                         return NULL;
 280                 }
 281
 282                 // Check if the node has a FindDir method
 283                 if(!curNode->FindDir) {
 284                         if(curNode->Close)      curNode->Close(curNode);
 285                         if(TruePath) {
 286                                 free(*TruePath);
 287                                 *TruePath = NULL;
 288                         }
 289                         Path[nextSlash] = '/';
 290                         //Log("FindDir fail on '%s'", Path);
 291                         LEAVE('n');
 292                         return NULL;
 293                 }
 294                 LOG("FindDir(%p, '%s')", curNode, &Path[ofs]);
 295                 // Get Child Node
 296                 tmpNode = curNode->FindDir(curNode, &Path[ofs]);
 297                 LOG("tmpNode = %p", tmpNode);
 298                 if(curNode->Close)
 299                         curNode->Close(curNode);
 300                 curNode = tmpNode;
 301
 302                 // Error Check
 303                 if(!curNode) {
 304                         LOG("Node '%s' not found in dir '%s'", &Path[ofs], Path);
 305                         if(TruePath) {
 306                                 free(*TruePath);
 307                                 *TruePath = NULL;
 308                         }
 309                         //Log("Child fail on '%s' ('%s)", Path, &Path[ofs]);
 310                         Path[nextSlash] = '/';
 311                         LEAVE('n');
 312                         return NULL;
 313                 }
 314
 315                 // Handle Symbolic Links
 316                 if(curNode->Flags & VFS_FFLAG_SYMLINK) {
 317                         if(TruePath) {
 318                                 free(*TruePath);
 319                                 *TruePath = NULL;
 320                         }
 321                         tmp = malloc( curNode->Size + 1 );
 322                         curNode->Read( curNode, 0, curNode->Size, tmp );
 323                         tmp[ curNode->Size ] = '\0';
 324
 325                         // Parse Symlink Path
 326                         curNode = VFS_ParsePath(tmp, TruePath);
 327
 328                         // Error Check
 329                         if(!curNode) {
 330                                 Log("Symlink fail '%s'", tmp);
 331                                 free(tmp);      // Free temp string
 332                                 LEAVE('n');
 333                                 return NULL;
 334                         }
 335
 336                         // Set Path Variable
 337                         if(TruePath) {
 338                                 *TruePath = tmp;
 339                                 retLength = strlen(tmp);
 340                         } else {
 341                                 free(tmp);      // Free temp string
 342                         }
 343
 344                         continue;
 345                 }
 346
 347                 // Handle Non-Directories
 348                 if( !(curNode->Flags & VFS_FFLAG_DIRECTORY) )
 349                 {
 350                         Warning("VFS_ParsePath - File in directory context");
 351                         if(TruePath)    free(*TruePath);
 352                         LEAVE('n');
 353                         return NULL;
 354                 }
 355
 356                 // Check if path needs extending
 357                 if(!TruePath)   continue;
 358
 359                 // Increase buffer space
 360                 tmp = realloc( *TruePath, retLength + strlen(&Path[ofs]) + 1 + 1 );
 361                 // Check if allocation succeeded
 362                 if(!tmp) {
 363                         Warning("VFS_ParsePath -  Unable to reallocate true path buffer");
 364                         free(*TruePath);
 365                         if(curNode->Close)      curNode->Close(curNode);
 366                         LEAVE('n');
 367                         return NULL;
 368                 }
 369                 *TruePath = tmp;
 370                 // Append to path
 371                 (*TruePath)[retLength] = '/';
 372                 strcpy(*TruePath+retLength+1, &Path[ofs]);
 373                 // - Extend Path
 374                 retLength += strlen(&Path[ofs])+1;
 375         }
 376
 377         // Get last node
 378         LOG("VFS_ParsePath: FindDir(%p, '%s')", curNode, &Path[ofs]);
 379         tmpNode = curNode->FindDir(curNode, &Path[ofs]);
 380         LOG("tmpNode = %p", tmpNode);
 381         if(curNode->Close)      curNode->Close(curNode);
 382         // Check if file was found
 383         if(!tmpNode) {
 384                 LOG("Node '%s' not found in dir '%s'", &Path[ofs], Path);
 385                 //Log("Child fail '%s' ('%s')", Path, &Path[ofs]);
 386                 if(TruePath)    free(*TruePath);
 387                 if(curNode->Close)      curNode->Close(curNode);
 388                 LEAVE('n');
 389                 return NULL;
 390         }
 391
 392         if(TruePath)
 393         {
 394                 // Increase buffer space
 395                 tmp = realloc(*TruePath, retLength + strlen(&Path[ofs]) + 1 + 1);
 396                 // Check if allocation succeeded
 397                 if(!tmp) {
 398                         Warning("VFS_ParsePath -  Unable to reallocate true path buffer");
 399                         free(*TruePath);
 400                         if(tmpNode->Close)      tmpNode->Close(curNode);
 401                         LEAVE('n');
 402                         return NULL;
 403                 }
 404                 *TruePath = tmp;
 405                 // Append to path
 406                 (*TruePath)[retLength] = '/';
 407                 strcpy(*TruePath + retLength + 1, &Path[ofs]);
 408                 // - Extend Path
 409                 //retLength += strlen(tmpNode->Name) + 1;
 410         }
 411
 412         LEAVE('p', tmpNode);
 413         return tmpNode;
 414 }
 415
 416 /**
 417  * \fn int VFS_Open(char *Path, Uint Mode)
 418  * \brief Open a file
 419  */
 420 int VFS_Open(char *Path, Uint Mode)
 421 {
 422         tVFS_Node       *node;
 423         char    *absPath;
 424          int    i;
 425
 426         ENTER("sPath xMode", Path, Mode);
 427
 428         // Get absolute path
 429         absPath = VFS_GetAbsPath(Path);
 430         LOG("absPath = \"%s\"", absPath);
 431         // Parse path and get mount point
 432         node = VFS_ParsePath(absPath, NULL);
 433         // Free generated path
 434         free(absPath);
 435
 436         if(!node) {
 437                 LOG("Cannot find node");
 438                 LEAVE('i', -1);
 439                 return -1;
 440         }
 441
 442         // Check for symlinks
 443         if( !(Mode & VFS_OPENFLAG_NOLINK) && (node->Flags & VFS_FFLAG_SYMLINK) )
 444         {
 445                 if( !node->Read ) {
 446                         Warning("No read method on symlink");
 447                         LEAVE('i', -1);
 448                         return -1;
 449                 }
 450                 absPath = malloc(node->Size+1); // Allocate Buffer
 451                 node->Read( node, 0, node->Size, absPath );     // Read Path
 452
 453                 absPath[ node->Size ] = '\0';   // End String
 454                 if(node->Close) node->Close( node );    // Close old node
 455                 node = VFS_ParsePath(absPath, NULL);    // Get new node
 456                 free( absPath );        // Free allocated path
 457         }
 458
 459         if(!node) {
 460                 LOG("Cannot find node");
 461                 LEAVE('i', -1);
 462                 return -1;
 463         }
 464
 465         i = 0;
 466         i |= (Mode & VFS_OPENFLAG_EXEC) ? VFS_PERM_EXECUTE : 0;
 467         i |= (Mode & VFS_OPENFLAG_READ) ? VFS_PERM_READ : 0;
 468         i |= (Mode & VFS_OPENFLAG_WRITE) ? VFS_PERM_WRITE : 0;
 469
 470         LOG("i = 0b%b", i);
 471
 472         // Permissions Check
 473         if( !VFS_CheckACL(node, i) ) {
 474                 node->Close( node );
 475                 Log("VFS_Open: Permissions Failed");
 476                 LEAVE('i', -1);
 477                 return -1;
 478         }
 479
 480         // Check for a user open
 481         if(Mode & VFS_OPENFLAG_USER)
 482         {
 483                 // Allocate Buffer
 484                 if( MM_GetPhysAddr( (Uint)gaUserHandles ) == 0 )
 485                 {
 486                         Uint    addr, size;
 487                         size = CFGINT(CFG_VFS_MAXFILES) * sizeof(tVFS_Handle);
 488                         for(addr = 0; addr < size; addr += 0x1000)
 489                                 MM_Allocate( (Uint)gaUserHandles + addr );
 490                         memset( gaUserHandles, 0, size );
 491                 }
 492                 // Get a handle
 493                 for(i=0;i<CFGINT(CFG_VFS_MAXFILES);i++)
 494                 {
 495                         if(gaUserHandles[i].Node)       continue;
 496                         gaUserHandles[i].Node = node;
 497                         gaUserHandles[i].Position = 0;
 498                         gaUserHandles[i].Mode = Mode;
 499                         LEAVE('i', i);
 500                         return i;
 501                 }
 502         }
 503         else
 504         {
 505                 // Allocate space if not already
 506                 if( MM_GetPhysAddr( (Uint)gaKernelHandles ) == 0 )
 507                 {
 508                         Uint    addr, size;
 509                         size = MAX_KERNEL_FILES * sizeof(tVFS_Handle);
 510                         for(addr = 0; addr < size; addr += 0x1000)
 511                                 MM_Allocate( (Uint)gaKernelHandles + addr );
 512                         memset( gaKernelHandles, 0, size );
 513                 }
 514                 // Get a handle
 515                 for(i=0;i<MAX_KERNEL_FILES;i++)
 516                 {
 517                         if(gaKernelHandles[i].Node)     continue;
 518                         gaKernelHandles[i].Node = node;
 519                         gaKernelHandles[i].Position = 0;
 520                         gaKernelHandles[i].Mode = Mode;
 521                         LEAVE('x', i|VFS_KERNEL_FLAG);
 522                         return i|VFS_KERNEL_FLAG;
 523                 }
 524         }
 525
 526         Log("VFS_Open: Out of handles");
 527         LEAVE('i', -1);
 528         return -1;
 529 }
 530
 531 /**
 532  * \fn void VFS_Close(int FD)
 533  * \brief Closes an open file handle
 534  */
 535 void VFS_Close(int FD)
 536 {
 537         tVFS_Handle     *h;
 538
 539         // Get handle
 540         h = VFS_GetHandle(FD);
 541         if(h == NULL) {
 542                 Warning("Invalid file handle passed to VFS_Close, 0x%x\n", FD);
 543                 return;
 544         }
 545
 546         if(h->Node->Close)
 547                 h->Node->Close( h->Node );
 548
 549         h->Node = NULL;
 550 }
 551
 552 /**
 553  * \fn int VFS_ChDir(char *New)
 554  * \brief Change current working directory
 555  */
 556 int VFS_ChDir(char *New)
 557 {
 558         char    *buf;
 559          int    fd;
 560         tVFS_Handle     *h;
 561
 562         // Create Absolute
 563         buf = VFS_GetAbsPath(New);
 564         if(buf == NULL) {
 565                 Log("VFS_ChDir: Path expansion failed");
 566                 return -1;
 567         }
 568
 569         // Check if path exists
 570         fd = VFS_Open(buf, VFS_OPENFLAG_EXEC);
 571         if(fd == -1) {
 572                 Log("VFS_ChDir: Path is invalid");
 573                 return -1;
 574         }
 575
 576         // Get node so we can check for directory
 577         h = VFS_GetHandle(fd);
 578         if( !(h->Node->Flags & VFS_FFLAG_DIRECTORY) ) {
 579                 Log("VFS_ChDir: Path is not a directory");
 580                 VFS_Close(fd);
 581                 return -1;
 582         }
 583
 584         // Close file
 585         VFS_Close(fd);
 586
 587         // Free old working directory
 588         if( CFGPTR(CFG_VFS_CWD) )
 589                 free( CFGPTR(CFG_VFS_CWD) );
 590         // Set new
 591         CFGPTR(CFG_VFS_CWD) = buf;
 592
 593         Log("Updated CWD to '%s'", buf);
 594
 595         return 1;
 596 }
 597
 598 /**
 599  * \fn int VFS_ChRoot(char *New)
 600  * \brief Change current root directory
 601  */
 602 int VFS_ChRoot(char *New)
 603 {
 604         char    *buf;
 605          int    fd;
 606         tVFS_Handle     *h;
 607
 608         if(New[0] == '/' && New[1] == '\0')
 609                 return 1;       // What a useless thing to ask!
 610
 611         // Create Absolute
 612         buf = VFS_GetAbsPath(New);
 613         if(buf == NULL) {
 614                 LOG("Path expansion failed");
 615                 return -1;
 616         }
 617
 618         // Check if path exists
 619         fd = VFS_Open(buf, VFS_OPENFLAG_EXEC);
 620         if(fd == -1) {
 621                 LOG("Path is invalid");
 622                 return -1;
 623         }
 624
 625         // Get node so we can check for directory
 626         h = VFS_GetHandle(fd);
 627         if( !(h->Node->Flags & VFS_FFLAG_DIRECTORY) ) {
 628                 LOG("Path is not a directory");
 629                 VFS_Close(fd);
 630                 return -1;
 631         }
 632
 633         // Close file
 634         VFS_Close(fd);
 635
 636         // Free old working directory
 637         if( CFGPTR(CFG_VFS_CHROOT) )
 638                 free( CFGPTR(CFG_VFS_CHROOT) );
 639         // Set new
 640         CFGPTR(CFG_VFS_CHROOT) = buf;
 641
 642         LOG("Updated Root to '%s'", buf);
 643
 644         return 1;
 645 }
 646
 647 /**
 648  * \fn tVFS_Handle *VFS_GetHandle(int FD)
 649  * \brief Gets a pointer to the handle information structure
 650  */
 651 tVFS_Handle *VFS_GetHandle(int FD)
 652 {
 653         tVFS_Handle     *h;
 654
 655         if(FD < 0)      return NULL;
 656
 657         if(FD & VFS_KERNEL_FLAG) {
 658                 FD &= (VFS_KERNEL_FLAG - 1);
 659                 if(FD >= MAX_KERNEL_FILES)      return NULL;
 660                 h = &gaKernelHandles[ FD ];
 661         } else {
 662                 if(FD >= CFGINT(CFG_VFS_MAXFILES))      return NULL;
 663                 h = &gaUserHandles[ FD ];
 664         }
 665
 666         if(h->Node == NULL)     return NULL;
 667         return h;
 668 }
 669
 670 // === EXPORTS ===
 671 EXPORT(VFS_Open);
 672 EXPORT(VFS_Close);