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