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