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                 //Log("ret = '%s'\n", ret);
  77         }
  78
  79         // Parse Path
  80         pathComps[iPos++] = tmpStr = ret+1;
  81         while(*tmpStr)
  82         {
  83                 if(*tmpStr++ == '/')
  84                 {
  85                         pathComps[iPos++] = tmpStr;
  86                         if(iPos == MAX_PATH_SLASHES) {
  87                                 LOG("Path '%s' has too many elements", Path);
  88                                 free(ret);
  89                                 LEAVE('n');
  90                                 return NULL;
  91                         }
  92                 }
  93         }
  94         pathComps[iPos] = NULL;
  95
  96         // Cleanup
  97         iPos2 = iPos = 0;
  98         while(pathComps[iPos])
  99         {
 100                 tmpStr = pathComps[iPos];
 101                 // Always Increment iPos
 102                 iPos++;
 103                 // ..
 104                 if(tmpStr[0] == '.' && tmpStr[1] == '.' && (tmpStr[2] == '/' || tmpStr[2] == '\0') )
 105                 {
 106                         if(iPos2 != 0)
 107                                 iPos2 --;
 108                         continue;
 109                 }
 110                 // .
 111                 if(tmpStr[0] == '.' && (tmpStr[1] == '/' || tmpStr[1] == '\0') )
 112                 {
 113                         continue;
 114                 }
 115                 // Empty
 116                 if(tmpStr[0] == '/' || tmpStr[0] == '\0')
 117                 {
 118                         continue;
 119                 }
 120
 121                 // Set New Position
 122                 pathComps[iPos2] = tmpStr;
 123                 iPos2++;
 124         }
 125         pathComps[iPos2] = NULL;
 126
 127         // Build New Path
 128         iPos2 = 1;      iPos = 0;
 129         ret[0] = '/';
 130         while(pathComps[iPos])
 131         {
 132                 tmpStr = pathComps[iPos];
 133                 while(*tmpStr && *tmpStr != '/')
 134                 {
 135                         ret[iPos2++] = *tmpStr;
 136                         tmpStr++;
 137                 }
 138                 ret[iPos2++] = '/';
 139                 iPos++;
 140         }
 141         if(iPos2 > 1)
 142                 ret[iPos2-1] = 0;
 143         else
 144                 ret[iPos2] = 0;
 145
 146         LEAVE('s', ret);
 147         //Log("VFS_GetAbsPath: RETURN '%s'", ret);
 148         return ret;
 149 }
 150
 151 /**
 152  * \fn char *VFS_ParsePath(char *Path, char **TruePath)
 153  * \brief Parses a path, resolving sysmlinks and applying permissions
 154  */
 155 tVFS_Node *VFS_ParsePath(char *Path, char **TruePath)
 156 {
 157         tVFS_Mount      *mnt;
 158         tVFS_Mount      *longestMount = gRootMount;     // Root is first
 159          int    cmp, retLength = 0;
 160          int    ofs, nextSlash;
 161         tVFS_Node       *curNode, *tmpNode;
 162         char    *tmp;
 163
 164         ENTER("sPath pTruePath", Path, TruePath);
 165
 166         // Memory File
 167         if(Path[0] == '$') {
 168                 if(TruePath) {
 169                         *TruePath = malloc(strlen(Path)+1);
 170                         strcpy(*TruePath, Path);
 171                 }
 172                 curNode = gVFS_MemRoot.FindDir(&gVFS_MemRoot, Path);
 173                 LEAVE('p', curNode);
 174                 return curNode;
 175         }
 176         // For root we always fast return
 177
 178         if(Path[0] == '/' && Path[1] == '\0') {
 179                 if(TruePath) {
 180                         *TruePath = malloc( gRootMount->MountPointLen+1 );
 181                         strcpy(*TruePath, gRootMount->MountPoint);
 182                 }
 183                 LEAVE('p', gRootMount->RootNode);
 184                 return gRootMount->RootNode;
 185         }
 186
 187         // Check if there is anything mounted
 188         if(!gMounts) {
 189                 Warning("WTF! There's nothing mounted?");
 190                 return NULL;
 191         }
 192
 193         // Find Mountpoint
 194         for(mnt = gMounts;
 195                 mnt;
 196                 mnt = mnt->Next)
 197         {
 198                 // Quick Check
 199                 if( Path[mnt->MountPointLen] != '/' && Path[mnt->MountPointLen] != '\0')
 200                         continue;
 201                 // Length Check - If the length is smaller than the longest match sofar
 202                 if(mnt->MountPointLen < longestMount->MountPointLen)    continue;
 203                 // String Compare
 204                 cmp = strcmp(Path, mnt->MountPoint);
 205
 206                 #if OPEN_MOUNT_ROOT
 207                 // Fast Break - Request Mount Root
 208                 if(cmp == 0) {
 209                         if(TruePath) {
 210                                 *TruePath = malloc( mnt->MountPointLen+1 );
 211                                 strcpy(*TruePath, mnt->MountPoint);
 212                         }
 213                         LEAVE('p', mnt->RootNode);
 214                         return mnt->RootNode;
 215                 }
 216                 #endif
 217                 // Not a match, continue
 218                 if(cmp != '/')  continue;
 219                 longestMount = mnt;
 220         }
 221
 222         // Sanity Check
 223         /*if(!longestMount) {
 224                 Log("VFS_ParsePath - ERROR: No Root Node\n");
 225                 return NULL;
 226         }*/
 227
 228         // Save to shorter variable
 229         mnt = longestMount;
 230
 231         LOG("mnt = {MountPoint:\"%s\"}", mnt->MountPoint);
 232
 233         // Initialise String
 234         if(TruePath)
 235         {
 236                 *TruePath = malloc( mnt->MountPointLen+1 );
 237                 strcpy(*TruePath, mnt->MountPoint);
 238                 retLength = mnt->MountPointLen;
 239         }
 240
 241         curNode = mnt->RootNode;
 242         curNode->ReferenceCount ++;
 243         // Parse Path
 244         ofs = mnt->MountPointLen+1;
 245         for(; (nextSlash = strpos(&Path[ofs], '/')) != -1; Path[nextSlash]='/',ofs = nextSlash + 1)
 246         {
 247                 nextSlash += ofs;
 248                 Path[nextSlash] = '\0';
 249
 250                 // Check for empty string
 251                 if( Path[ofs] == '\0' ) continue;
 252
 253                 // Check permissions on root of filesystem
 254                 if( !VFS_CheckACL(curNode, VFS_PERM_EXECUTE) ) {
 255                         curNode->Close( curNode );
 256                         if(TruePath) {
 257                                 free(*TruePath);
 258                                 *TruePath = NULL;
 259                         }
 260                         //Log("Permissions fail on '%s'", Path);
 261                         LEAVE('n');
 262                         return NULL;
 263                 }
 264
 265                 // Check if the node has a FindDir method
 266                 if(!curNode->FindDir) {
 267                         if(curNode->Close)      curNode->Close(curNode);
 268                         if(TruePath) {
 269                                 free(*TruePath);
 270                                 *TruePath = NULL;
 271                         }
 272                         Path[nextSlash] = '/';
 273                         //Log("FindDir fail on '%s'", Path);
 274                         LEAVE('n');
 275                         return NULL;
 276                 }
 277                 LOG("FindDir(%p, '%s')", curNode, &Path[ofs]);
 278                 // Get Child Node
 279                 tmpNode = curNode->FindDir(curNode, &Path[ofs]);
 280                 LOG("tmpNode = %p", tmpNode);
 281                 if(curNode->Close)
 282                         curNode->Close(curNode);
 283                 curNode = tmpNode;
 284
 285                 // Error Check
 286                 if(!curNode) {
 287                         LOG("Node '%s' not found in dir '%s'", &Path[ofs], Path);
 288                         if(TruePath) {
 289                                 free(*TruePath);
 290                                 *TruePath = NULL;
 291                         }
 292                         //Log("Child fail on '%s' ('%s)", Path, &Path[ofs]);
 293                         Path[nextSlash] = '/';
 294                         LEAVE('n');
 295                         return NULL;
 296                 }
 297
 298                 // Handle Symbolic Links
 299                 if(curNode->Flags & VFS_FFLAG_SYMLINK) {
 300                         if(TruePath) {
 301                                 free(*TruePath);
 302                                 *TruePath = NULL;
 303                         }
 304                         tmp = malloc( curNode->Size + 1 );
 305                         curNode->Read( curNode, 0, curNode->Size, tmp );
 306                         tmp[ curNode->Size ] = '\0';
 307
 308                         // Parse Symlink Path
 309                         curNode = VFS_ParsePath(tmp, TruePath);
 310
 311                         // Error Check
 312                         if(!curNode) {
 313                                 Log("Symlink fail '%s'", tmp);
 314                                 free(tmp);      // Free temp string
 315                                 LEAVE('n');
 316                                 return NULL;
 317                         }
 318
 319                         // Set Path Variable
 320                         if(TruePath) {
 321                                 *TruePath = tmp;
 322                                 retLength = strlen(tmp);
 323                         } else {
 324                                 free(tmp);      // Free temp string
 325                         }
 326
 327                         continue;
 328                 }
 329
 330                 // Handle Non-Directories
 331                 if( !(curNode->Flags & VFS_FFLAG_DIRECTORY) )
 332                 {
 333                         Warning("VFS_ParsePath - File in directory context");
 334                         if(TruePath)    free(*TruePath);
 335                         LEAVE('n');
 336                         return NULL;
 337                 }
 338
 339                 // Check if path needs extending
 340                 if(!TruePath)   continue;
 341
 342                 // Increase buffer space
 343                 tmp = realloc( *TruePath, retLength + strlen(&Path[ofs]) + 1 + 1 );
 344                 // Check if allocation succeeded
 345                 if(!tmp) {
 346                         Warning("VFS_ParsePath -  Unable to reallocate true path buffer");
 347                         free(*TruePath);
 348                         if(curNode->Close)      curNode->Close(curNode);
 349                         LEAVE('n');
 350                         return NULL;
 351                 }
 352                 *TruePath = tmp;
 353                 // Append to path
 354                 (*TruePath)[retLength] = '/';
 355                 strcpy(*TruePath+retLength+1, &Path[ofs]);
 356                 // - Extend Path
 357                 retLength += strlen(&Path[ofs])+1;
 358         }
 359
 360         // Get last node
 361         LOG("VFS_ParsePath: FindDir(%p, '%s')", curNode, &Path[ofs]);
 362         tmpNode = curNode->FindDir(curNode, &Path[ofs]);
 363         LOG("tmpNode = %p", tmpNode);
 364         if(curNode->Close)      curNode->Close(curNode);
 365         // Check if file was found
 366         if(!tmpNode) {
 367                 LOG("Node '%s' not found in dir '%s'", &Path[ofs], Path);
 368                 Log("Child fail '%s' ('%s')", Path, &Path[ofs]);
 369                 if(TruePath)    free(*TruePath);
 370                 if(curNode->Close)      curNode->Close(curNode);
 371                 LEAVE('n');
 372                 return NULL;
 373         }
 374
 375         if(TruePath)
 376         {
 377                 // Increase buffer space
 378                 tmp = realloc(*TruePath, retLength + strlen(&Path[ofs]) + 1 + 1);
 379                 // Check if allocation succeeded
 380                 if(!tmp) {
 381                         Warning("VFS_ParsePath -  Unable to reallocate true path buffer");
 382                         free(*TruePath);
 383                         if(tmpNode->Close)      tmpNode->Close(curNode);
 384                         LEAVE('n');
 385                         return NULL;
 386                 }
 387                 *TruePath = tmp;
 388                 // Append to path
 389                 (*TruePath)[retLength] = '/';
 390                 strcpy(*TruePath + retLength + 1, &Path[ofs]);
 391                 // - Extend Path
 392                 //retLength += strlen(tmpNode->Name) + 1;
 393         }
 394
 395         LEAVE('p', tmpNode);
 396         return tmpNode;
 397 }
 398
 399 /**
 400  * \fn int VFS_Open(char *Path, Uint Mode)
 401  * \brief Open a file
 402  */
 403 int VFS_Open(char *Path, Uint Mode)
 404 {
 405         tVFS_Node       *node;
 406         char    *absPath;
 407          int    i;
 408
 409         ENTER("sPath xMode", Path, Mode);
 410
 411         // Get absolute path
 412         absPath = VFS_GetAbsPath(Path);
 413         LOG("absPath = \"%s\"", absPath);
 414         // Parse path and get mount point
 415         node = VFS_ParsePath(absPath, NULL);
 416         // Free generated path
 417         free(absPath);
 418
 419         if(!node) {
 420                 LOG("Cannot find node");
 421                 LEAVE('i', -1);
 422                 return -1;
 423         }
 424
 425         // Check for symlinks
 426         if( !(Mode & VFS_OPENFLAG_NOLINK) && (node->Flags & VFS_FFLAG_SYMLINK) )
 427         {
 428                 if( !node->Read ) {
 429                         Warning("No read method on symlink");
 430                         LEAVE('i', -1);
 431                         return -1;
 432                 }
 433                 absPath = malloc(node->Size+1); // Allocate Buffer
 434                 node->Read( node, 0, node->Size, absPath );     // Read Path
 435
 436                 absPath[ node->Size ] = '\0';   // End String
 437                 if(node->Close) node->Close( node );    // Close old node
 438                 node = VFS_ParsePath(absPath, NULL);    // Get new node
 439                 free( absPath );        // Free allocated path
 440         }
 441
 442         if(!node) {
 443                 LOG("Cannot find node");
 444                 LEAVE('i', -1);
 445                 return -1;
 446         }
 447
 448         i = 0;
 449         i |= (Mode & VFS_OPENFLAG_EXEC) ? VFS_PERM_EXECUTE : 0;
 450         i |= (Mode & VFS_OPENFLAG_READ) ? VFS_PERM_READ : 0;
 451         i |= (Mode & VFS_OPENFLAG_WRITE) ? VFS_PERM_WRITE : 0;
 452
 453         LOG("i = 0b%b", i);
 454
 455         // Permissions Check
 456         if( !VFS_CheckACL(node, i) ) {
 457                 node->Close( node );
 458                 Log("VFS_Open: Permissions Failed");
 459                 LEAVE('i', -1);
 460                 return -1;
 461         }
 462
 463         // Check for a user open
 464         if(Mode & VFS_OPENFLAG_USER)
 465         {
 466                 // Allocate Buffer
 467                 if( MM_GetPhysAddr( (Uint)gaUserHandles ) == 0 )
 468                 {
 469                         Uint    addr, size;
 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 }