+
+ return phys_start;
+}
+
+
+//
+// Get the embedded offset (if any) for an hfs+ volume.
+// This is pretty skanky that we have to do this but
+// that's life...
+//
+#include <sys/disk.h>
+#include <hfs/hfs_format.h>
+
+#include <machine/endian.h>
+
+#define HFS_PRI_SECTOR(blksize) (1024 / (blksize))
+#define HFS_PRI_OFFSET(blksize) ((blksize) > 1024 ? 1024 : 0)
+
+#define SWAP_BE16(x) ntohs(x)
+#define SWAP_BE32(x) ntohl(x)
+
+
+off_t
+get_embedded_offset(char *devname)
+{
+ int fd = -1;
+ off_t ret = 0;
+ char *buff = NULL, rawdev[256];
+ u_int64_t blkcnt;
+ u_int32_t blksize;
+ HFSMasterDirectoryBlock *mdbp;
+ off_t embeddedOffset;
+ struct statfs sfs;
+ struct stat st;
+
+ restart:
+ if (stat(devname, &st) != 0) {
+ fprintf(stderr, "Could not access %s (%s)\n", devname, strerror(errno));
+ ret = -1;
+ goto out;
+ }
+
+ if (S_ISCHR(st.st_mode) == 0) {
+ // hmmm, it's not the character special raw device so we
+ // should try to figure out the real device.
+ if (statfs(devname, &sfs) != 0) {
+ fprintf(stderr, "Can't find out any info about the fs for path %s (%s)\n",
+ devname, strerror(errno));
+ ret = -1;
+ goto out;
+ }
+
+ // copy the "/dev/"
+ strncpy(rawdev, sfs.f_mntfromname, 5);
+ rawdev[5] = 'r';
+ strcpy(&rawdev[6], &sfs.f_mntfromname[5]);
+ devname = &rawdev[0];
+ goto restart;
+ }
+
+ fd = open(devname, O_RDONLY);
+ if (fd < 0) {
+ fprintf(stderr, "can't open: %s (%s)\n", devname, strerror(errno));
+ ret = -1;
+ goto out;
+ }
+
+ /* Get the real physical block size. */
+ if (ioctl(fd, DKIOCGETBLOCKSIZE, (caddr_t)&blksize) != 0) {
+ fprintf(stderr, "can't get the device block size (%s). assuming 512\n", strerror(errno));
+ blksize = 512;
+ ret = -1;
+ goto out;
+ }
+
+ /* Get the number of physical blocks. */
+ if (ioctl(fd, DKIOCGETBLOCKCOUNT, (caddr_t)&blkcnt)) {
+ struct stat st;
+ fprintf(stderr, "failed to get block count. trying stat().\n");
+ if (fstat(fd, &st) != 0) {
+ ret = -1;
+ goto out;
+ }
+
+ blkcnt = st.st_size / blksize;
+ }
+
+ /*
+ * There are only 31 bits worth of block count in
+ * the buffer cache. So for large volumes a 4K
+ * physical block size is needed.
+ */
+ if (blksize == 512 && blkcnt > (u_int64_t)0x000000007fffffff) {
+ blksize = 4096;
+ }
+
+ /*
+ * At this point:
+ * blksize has our prefered physical block size
+ * blkcnt has the total number of physical blocks
+ */
+
+ buff = (char *)malloc(blksize);
+
+ if (pread(fd, buff, blksize, HFS_PRI_SECTOR(blksize)*blksize) != blksize) {
+ fprintf(stderr, "failed to read volume header @ offset %d (%s)\n",
+ HFS_PRI_SECTOR(blksize), strerror(errno));
+ ret = -1;
+ goto out;
+ }
+
+ mdbp = (HFSMasterDirectoryBlock *)buff;
+ if ( (SWAP_BE16(mdbp->drSigWord) != kHFSSigWord)
+ && (SWAP_BE16(mdbp->drSigWord) != kHFSPlusSigWord)
+ && (SWAP_BE16(mdbp->drSigWord) != kHFSXSigWord)) {
+ ret = -1;
+ goto out;
+ }
+
+ if ((SWAP_BE16(mdbp->drSigWord) == kHFSSigWord) && (SWAP_BE16(mdbp->drEmbedSigWord) != kHFSPlusSigWord)) {
+ ret = -1;
+ goto out;
+ } else if (SWAP_BE16(mdbp->drEmbedSigWord) == kHFSPlusSigWord) {
+ /* Get the embedded Volume Header */
+ embeddedOffset = SWAP_BE16(mdbp->drAlBlSt) * 512;
+ embeddedOffset += (u_int64_t)SWAP_BE16(mdbp->drEmbedExtent.startBlock) *
+ (u_int64_t)SWAP_BE32(mdbp->drAlBlkSiz);
+
+ /*
+ * If the embedded volume doesn't start on a block
+ * boundary, then switch the device to a 512-byte
+ * block size so everything will line up on a block
+ * boundary.
+ */
+ if ((embeddedOffset % blksize) != 0) {
+ fprintf(stderr, "HFS Mount: embedded volume offset not"
+ " a multiple of physical block size (%d);"
+ " switching to 512\n", blksize);
+
+ blkcnt *= (blksize / 512);
+ blksize = 512;
+ }
projects / apple / hfs.git / commitdiff
