CopyHFSMeta/SparseBundle.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4 #include <unistd.h>
   5 #include <fcntl.h>
   6 #include <err.h>
   7 #include <errno.h>
   8 #include <unistd.h>
   9 #include <sys/stat.h>
  10 #include <sys/fcntl.h>
  11 #include <removefile.h>
  12
  13 #include <CoreFoundation/CoreFoundation.h>
  14 #include <System/sys/fsctl.h>
  15
  16 #include "hfsmeta.h"
  17 #include "Sparse.h"
  18
  19 /*
  20  * Routines to maniupulate a sparse bundle.
  21  * N.B.:  The sparse bundle format it uses is a subset of
  22  * the real sparse bundle format:  no partition map, and
  23  * no encryption.
  24  */
  25
  26 #ifndef MIN
  27 # define MIN(a, b) \
  28         ({ __typeof(a) __a = (a); __typeof(b) __b = (b); \
  29                 __a < __b ? __a : __b; })
  30 #endif
  31
  32 /*
  33  * Context for the sparse bundle routines.  The path name,
  34  * size of the band files, and cached file descriptor and
  35  * band numbers, to reduce the amount of pathname lookups
  36  * required.
  37  */
  38 struct SparseBundleContext {
  39         char *pathname;
  40         size_t bandSize;
  41         int cfd;        // Cached file descriptor
  42         int cBandNum;   // cached bandfile number
  43 };
  44
  45 static const int kBandSize = 8388608;
  46
  47 // Prototype bundle Info.plist file
  48 static const char *bundlePrototype =
  49 "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
  50 "<!DOCTYPE plist PUBLIC \"-//Apple//DTD PLIST 1.0//EN\" \"http://www.apple.com/DTDs/PropertyList-1.0.dtd\">\n"
  51 "<plist version=\"1.0\">\n"
  52 "<dict>\n"
  53                 "\t<key>CFBundleInfoDictionaryVersion</key>\n"
  54                 "\t<string>6.0</string>\n"
  55                 "\t<key>band-size</key>\n"
  56                 "\t<integer>%d</integer>\n"
  57                 "\t<key>bundle-backingstore-version</key>\n"
  58                 "\t<integer>1</integer>\n"
  59                 "\t<key>diskimage-bundle-type</key>\n"
  60                 "\t<string>com.apple.diskimage.sparsebundle</string>\n"
  61                 "\t<key>size</key>\n"
  62                 "\t<integer>%llu</integer>\n"
  63 "</dict>\n"
  64         "</plist>\n";
  65
  66
  67 /*
  68  * Read from a sparse bundle.  If the band file doesn't exist, or is shorter than
  69  * what we need to get from it, we pad out with 0's.
  70  */
  71 static ssize_t
  72 doSparseRead(struct IOWrapper *context, off_t offset, void *buffer, off_t len)
  73 {
  74         struct SparseBundleContext *ctx = context->context;
  75         off_t blockSize = ctx->bandSize;
  76         ssize_t nread = 0;
  77         ssize_t retval = -1;
  78
  79         while (nread < len) {
  80                 off_t bandNum = (offset + nread) / blockSize;   // Which band file to use
  81                 off_t bandOffset = (offset + nread) % blockSize;        // how far to go into the file
  82                 ssize_t amount = MIN(len - nread, blockSize - bandOffset);      // How many bytes to write in this band file
  83                 char *bandName;
  84                 ssize_t n;
  85                 int fd;
  86
  87                 asprintf(&bandName, "%s/bands/%llx", ctx->pathname, bandNum);
  88                 if (!bandName) {
  89                         warn("Cannot allocate memory for path '%s/bands/%llx'", ctx->pathname, bandNum);
  90                         retval = -1;
  91                         goto done;
  92                 }
  93                 fd = open(bandName, O_RDONLY);
  94                 if (fd == -1) {
  95                         if (errno == ENOENT) {
  96                                 // Doesn't exist, so we just write zeroes
  97                                 free(bandName);
  98                                 memset(buffer + nread, 0, amount);
  99                                 nread += amount;
 100                                 continue;
 101                         }
 102                         warn("Cannot open band file %s for offset %llu", bandName, offset + nread);
 103                         retval = -1;
 104                         free(bandName);
 105                         goto done;
 106                 }
 107
 108                 n = pread(fd, (char*)buffer + nread, amount, bandOffset);
 109                 if (n == -1) {
 110                         warn("Cannot read from band file %s for offset %llu for amount %zu", bandName, offset+nread, amount);
 111                         close(fd);
 112                         free(bandName);
 113                         goto done;
 114                 }
 115                 if (n < amount) {       // hit EOF, pad out with zeroes
 116                         memset(buffer + nread + amount, 0, amount - n);
 117                 }
 118                 free(bandName);
 119                 close(fd);
 120                 nread += n;
 121         }
 122         retval = nread;
 123 done:
 124         return retval;
 125
 126 }
 127
 128 /*
 129  * Write a chunk of data to a bundle.
 130  */
 131 static ssize_t
 132 doSparseWrite(IOWrapper_t *context, off_t offset, void *buffer, off_t len)
 133 {
 134         struct SparseBundleContext *ctx = context->context;
 135         off_t blockSize = ctx->bandSize;
 136         ssize_t written = 0;
 137         ssize_t retval = -1;
 138
 139         while (written < len) {
 140                 off_t bandNum = (offset + written) / blockSize; // Which band file to use
 141                 off_t bandOffset = (offset + written) % blockSize;      // how far to go into the file
 142                 size_t amount = MIN(len - written, blockSize - bandOffset);     // How many bytes to write in this band file
 143                 ssize_t nwritten;
 144                 int fd;
 145
 146                 if (ctx->cfd == -1 || ctx->cBandNum != bandNum) {
 147                         char *bandName = NULL;
 148
 149                         if (ctx->cfd != -1) {
 150                                 close(ctx->cfd);
 151                                 ctx->cfd = -1;
 152                         }
 153                         asprintf(&bandName, "%s/bands/%llx", ctx->pathname, bandNum);
 154                         if (!bandName) {
 155                                 warnx("Cannot allocate memory for band %s/bands/%llx", ctx->pathname, bandNum);
 156                                 retval = -1;
 157                                 goto done;
 158                         }
 159
 160                         fd = open(bandName, O_WRONLY | O_CREAT, 0666);
 161                         if (fd == -1) {
 162                                 warn("Cannot open band file %s for offset %llu", bandName, offset + written);
 163                                 free(bandName);
 164                                 retval = -1;
 165                                 goto done;
 166                         }
 167                         /*
 168                          * When we create a new band file, we sync the volume
 169                          * it's on, so that we can ensure that the band file is present
 170                          * on disk.  (Otherwise, with a crash, we can end up with the
 171                          * data not where we expected.)  In this case, however, we probably
 172                          * don't need to wait for it -- just start the sync.
 173                          */
 174                         fsync_volume_np(fd, 0);
 175                         fcntl(fd, F_NOCACHE, 1);
 176                         free(bandName);
 177                         bandName = NULL;
 178                         ctx->cfd = fd;
 179                         ctx->cBandNum = bandNum;
 180                 } else {
 181                         fd = ctx->cfd;
 182                 }
 183                 nwritten = pwrite(fd, (char*)buffer + written, amount, bandOffset);
 184                 if (nwritten == -1) {
 185                         warn("Cannot write to band file %s/band/%llx for offset %llu for amount %zu", ctx->pathname, bandNum, offset+written, amount);
 186                         close(fd);
 187                         ctx->cfd = -1;
 188                         retval = -1;
 189                         goto done;
 190                 }
 191                 // Sync the data out.
 192                 fsync(fd);
 193                 written += nwritten;
 194         }
 195         retval = written;
 196 done:
 197         return retval;
 198
 199 }
 200
 201 /*
 202  * Write a given extent (<start, length> pair) from an input device to the
 203  * sparse bundle.  We also use a block to update progress.
 204  */
 205 static ssize_t
 206 WriteExtentToSparse(struct IOWrapper * context, DeviceInfo_t *devp, off_t start, off_t len, void (^bp)(off_t))
 207 {
 208         const ssize_t bufSize = 1024 * 1024;
 209         uint8_t *buffer = NULL;
 210         ssize_t retval = 0;
 211         off_t total = 0;
 212
 213         if (debug) printf("Writing extent <%lld, %lld>\n", start, len);
 214         buffer = malloc(bufSize);
 215         if (buffer == NULL) {
 216                 warn("%s(%s):  Could not allocate %zu bytes for buffer", __FILE__, __FUNCTION__, bufSize);
 217                 retval = -1;
 218                 goto done;
 219         }
 220
 221         while (total < len) {
 222                 ssize_t nread;
 223                 ssize_t nwritten;
 224                 ssize_t amt = MIN(bufSize, len - total);
 225                 nread = UnalignedRead(devp, buffer, amt, start + total);
 226                 if (nread == -1) {
 227                         warn("Cannot read from device at offset %lld", start + total);
 228                         retval = -1;
 229                         break;
 230                 }
 231                 if (nread < amt) {
 232                         warnx("Short read from source device -- got %zd, expected %zd", nread, amt);
 233                 }
 234                 nwritten = doSparseWrite(context, start + total, buffer, nread);
 235                 if (nwritten == -1) {
 236                         retval = -1;
 237                         break;
 238                 }
 239                 bp(nread);
 240                 total += nread;
 241         }
 242         if (debug) printf("\twrote %lld\n", total);
 243 done:
 244         if (buffer)
 245                 free(buffer);
 246         return retval;
 247 }
 248
 249 static const CFStringRef kBandSizeKey = CFSTR("band-size");
 250 static const CFStringRef kDevSizeKey = CFSTR("size");
 251
 252 /*
 253  * We need to be able to get the size of the "device" from a sparse bundle;
 254  * we do this by using CF routines to parse the Info.plist file, and then
 255  * get the two keys we care about:  band-size (size of the band files), and
 256  * size (size -- in bytes -- of the "disk").
 257  */
 258 static int
 259 GetSizesFromPlist(const char *path, size_t *bandSize, off_t *devSize)
 260 {
 261         int retval = -1;
 262         CFReadStreamRef inFile = NULL;
 263         CFURLRef inFileURL = NULL;
 264         CFStringRef cfPath = NULL;
 265         CFPropertyListRef cfDict = NULL;
 266         CFNumberRef cfVal = NULL;
 267         int tmpInt;
 268         long long tmpLL;
 269
 270
 271         inFileURL = CFURLCreateFromFileSystemRepresentation(NULL, (const UInt8 *)path, strlen(path), FALSE);
 272         if (inFileURL == NULL) {
 273                 if (debug) warn("Cannot create url from pathname %s", path);
 274                 goto done;
 275         }
 276
 277         inFile = CFReadStreamCreateWithFile(NULL, inFileURL);
 278         if (inFile == NULL) {
 279                 if (debug) warn("cannot create read stream from path %s", path);
 280                 goto done;
 281         }
 282
 283         if (CFReadStreamOpen(inFile) == FALSE) {
 284                 if (debug) warn("cannot open read stream");
 285                 goto done;
 286         }
 287
 288         cfDict = CFPropertyListCreateWithStream(NULL, inFile, 0, 0, NULL, NULL);
 289         if (cfDict == NULL) {
 290                 if (debug) warnx("cannot create propertly list from stream for path %s", path);
 291                 goto done;
 292         }
 293
 294         cfVal = CFDictionaryGetValue(cfDict, kBandSizeKey);
 295         if (cfVal == NULL) {
 296                 if (debug) warnx("cannot get bandsize key from plist");
 297                 goto done;
 298         }
 299
 300         if (CFNumberGetValue(cfVal, kCFNumberIntType, &tmpInt) == false) {
 301                 if (debug) warnx("cannot get value from band size number");
 302                 goto done;
 303         } else {
 304                 *bandSize = tmpInt;
 305         }
 306
 307         cfVal = CFDictionaryGetValue(cfDict, kDevSizeKey);
 308         if (cfVal == NULL) {
 309                 if (debug) warnx("cannot get dev size key from plist");
 310                 goto done;
 311         }
 312         if (CFNumberGetValue(cfVal, kCFNumberLongLongType, &tmpLL) == false) {
 313                 goto done;
 314         } else {
 315                 *devSize = tmpLL;
 316         }
 317         retval = 0;
 318
 319 done:
 320
 321         if (cfPath)
 322                 CFRelease(cfPath);
 323         if (inFileURL)
 324                 CFRelease(inFileURL);
 325         if (inFile)
 326                 CFRelease(inFile);
 327         if (cfDict)
 328                 CFRelease(cfDict);
 329         return retval;
 330 }
 331
 332 #define kProgressName "HC.progress.txt"
 333
 334 /*
 335  * Get the progress state from a sparse bundle.  If it's not there, then
 336  * no progress.
 337  */
 338 static off_t
 339 GetProgress(struct IOWrapper *context)
 340 {
 341         struct SparseBundleContext *ctx = context->context;
 342         FILE *fp = NULL;
 343         off_t retval = 0;
 344         char progFile[strlen(ctx->pathname) + sizeof(kProgressName) + 2];       // '/' and NUL
 345
 346         sprintf(progFile, "%s/%s", ctx->pathname, kProgressName);
 347         fp = fopen(progFile, "r");
 348         if (fp == NULL) {
 349                 goto done;
 350         }
 351         if (fscanf(fp, "%llu", &retval) != 1) {
 352                 retval = 0;
 353         }
 354         fclose(fp);
 355 done:
 356         return retval;
 357 }
 358
 359 /*
 360  * Write the progress information out.  This involves writing a file in
 361  * the sparse bundle with the amount -- in bytes -- we've written so far.
 362  */
 363 static void
 364 SetProgress(struct IOWrapper *context, off_t prog)
 365 {
 366         struct SparseBundleContext *ctx = context->context;
 367         FILE *fp = NULL;
 368         char progFile[strlen(ctx->pathname) + sizeof(kProgressName) + 2];       // '/' and NUL
 369
 370         sprintf(progFile, "%s/%s", ctx->pathname, kProgressName);
 371         if (prog == 0) {
 372                 remove(progFile);
 373         } else {
 374                 fp = fopen(progFile, "w");
 375                 if (fp) {
 376                         (void)fprintf(fp, "%llu\n", prog);
 377                         fclose(fp);
 378                 }
 379         }
 380         return;
 381 }
 382
 383 /*
 384  * Clean up.  This is used when we have to initialize the bundle, but don't
 385  * have any progress information -- in that case, we don't want to have any
 386  * of the old band files laying around.  We use removefile() to recursively
 387  * remove them, but keep the bands directory.
 388  */
 389 int
 390 doCleanup(struct IOWrapper *ctx)
 391 {
 392         struct SparseBundleContext *context = ctx->context;
 393         int rv = 0;
 394         char bandsDir[strlen(context->pathname) + sizeof("/bands") + 1];        // 1 for NUL
 395
 396         sprintf(bandsDir, "%s/bands", context->pathname);
 397
 398         if (debug)
 399                 fprintf(stderr, "Cleaning up, about to call removefile\n");
 400         rv = removefile(bandsDir, NULL, REMOVEFILE_RECURSIVE | REMOVEFILE_KEEP_PARENT);
 401         if (debug)
 402                 fprintf(stderr, "removefile returned %d\n", rv);
 403
 404         return (rv == 0) ? 0 : -1;
 405 }
 406
 407 /*
 408  * Initialize the IOWrapper structure for a sparse bundle.  This will
 409  * create the bundle directory (but not its parents!) if needed, and
 410  * will populate it out.  It checks to see if there is an existing bundle
 411  * of the same name, and, if so, ensures that the izes are correct.  Then
 412  * it sets up all the function pointers.
 413  */
 414 struct IOWrapper *
 415 InitSparseBundle(const char *path, DeviceInfo_t *devp)
 416 {
 417         struct SparseBundleContext ctx = { 0 };
 418         IOWrapper_t *wrapper = NULL;
 419         struct stat sb;
 420         char *tmpname = NULL;
 421         int tmplen;
 422
 423         if (strstr(path, ".sparsebundle") == NULL) {
 424                 asprintf(&ctx.pathname, "%s.sparsebundle", path);
 425         } else {
 426                 ctx.pathname = strdup(path);
 427         }
 428
 429         if (ctx.pathname == NULL) {
 430                 return NULL;
 431         }
 432
 433         if (lstat(ctx.pathname, &sb) == -1) {
 434                 if (errno != ENOENT) {
 435                         warn("cannot check sparse bundle %s", ctx.pathname);
 436                         goto done;
 437                 }
 438                 if (mkdir(ctx.pathname, 0777) == -1) {
 439                         warn("cannot create sparse bundle %s", ctx.pathname);
 440                         goto done;
 441                 }
 442         } else if ((sb.st_mode & S_IFMT) != S_IFDIR) {
 443                 warnx("sparse bundle object %s is not a directory", ctx.pathname);
 444                 goto done;
 445         }
 446         /* NB! All names we create inside the bundle directory are shorter
 447          * then "Info.plist", we re-use the buffer allocated here for
 448          * multiple file names. */
 449         tmplen = asprintf(&tmpname, "%s/Info.plist", ctx.pathname);
 450         if (tmpname == NULL) {
 451                 goto done;
 452         }
 453
 454         if (stat(tmpname, &sb) != -1) {
 455                 size_t bandSize = 0;
 456                 off_t devSize = 0;
 457                 if (GetSizesFromPlist(tmpname, &bandSize, &devSize) == -1) {
 458                         warnx("Existing sparse bundle can't be parsed");
 459                         goto done;
 460                 }
 461                 if (debug)
 462                         printf("Existing sparse bundle size = %lld, bandsize = %zu\n", devSize, bandSize);
 463
 464                 if (devSize != devp->size) {
 465                         warnx("Existing sparse bundle size (%lld) != dev size (%lld)", devSize, devp->size);
 466                         goto done;
 467                 }
 468                 ctx.bandSize = bandSize;
 469         } else {
 470                 FILE *fp = fopen(tmpname, "w");
 471                 if (fp == NULL) {
 472                         warn("cannot create sparse bundle info plist %s", tmpname);
 473                         goto done;
 474                 }
 475                 ctx.bandSize = kBandSize;
 476                 if (fprintf(fp, bundlePrototype, kBandSize, devp->size) < 0) {
 477                         warn("failed to set bundle information in %s", tmpname);
 478                         fclose(fp); /* eat error return */
 479                         goto done;
 480                 }
 481                 if (fclose(fp) != 0) {
 482                         warn("failed to update bundle information in %s", tmpname);
 483                         goto done;
 484                 }
 485                 snprintf(tmpname, tmplen + 1, "%s/Info.bckup", ctx.pathname);
 486                 if ((int)strlen(tmpname) == tmplen) { /* Only update backup if we get the full path */
 487                         /* Failure to create a backup is not fatal */
 488                         fp = fopen(tmpname, "w");
 489                         if (fp) {
 490                                 if ((fprintf(fp, bundlePrototype, kBandSize, devp->size) < 0) ||
 491                                         (fclose(fp) < 0)) {
 492                                         unlink(tmpname);
 493                                 }
 494                         }
 495                 } else {
 496                         warn("Cannot create backup bundle information file in %s", tmpname);
 497                 }
 498                 if ((snprintf(tmpname, tmplen + 1, "%s/bands", ctx.pathname) > tmplen) ||
 499                         (mkdir(tmpname, 0777) == -1)) {
 500                         warn("cannot create bands directory in sparse bundle %s", ctx.pathname);
 501                         goto done;
 502                 }
 503                 if (snprintf(tmpname, tmplen + 1, "%s/token", ctx.pathname) <= tmplen) {
 504                         close(open(tmpname, O_CREAT | O_TRUNC, 0666));
 505                 }
 506         }
 507
 508         wrapper = malloc(sizeof(*wrapper));
 509         if (wrapper) {
 510                 struct SparseBundleContext *wrapped_ctx;
 511
 512                 wrapped_ctx = malloc(sizeof(*wrapped_ctx));
 513                 if (wrapped_ctx) {
 514                         *wrapped_ctx = ctx;
 515                         wrapped_ctx->cfd = -1;
 516
 517                         wrapper->writer = &WriteExtentToSparse;
 518                         wrapper->reader = &doSparseRead;
 519                         wrapper->getprog = &GetProgress;
 520                         wrapper->setprog = &SetProgress;
 521                         wrapper->cleanup = &doCleanup;
 522                         wrapper->context = wrapped_ctx;
 523                 } else {
 524                         free(wrapper);
 525                         wrapper = NULL;
 526                 }
 527         }
 528 done:
 529         if (wrapper == NULL) {
 530                 if (ctx.pathname)
 531                         free(ctx.pathname);
 532         }
 533
 534         free(tmpname);
 535         return wrapper;
 536 }