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