uapp/fsck-msdosfs/boot.c

37 	u_char block[DOSBOOTBLOCKSIZE];
43 	if ((size_t)read(dosfs, block, sizeof block) != sizeof block) {
44 		perr("could not read boot block");
48 	if (block[510] != 0x55 || block[511] != 0xaa) {
49 		pfatal("Invalid signature in boot block: %02x%02x",
50 		    block[511], block[510]);
57 	/* decode bios parameter block */
58 	boot->bpbBytesPerSec = block[11] + (block[12] << 8);
59 	boot->bpbSecPerClust = block[13];
60 	boot->bpbResSectors = block[14] + (block[15] << 8);
61 	boot->bpbFATs = block[16];
62 	boot->bpbRootDirEnts = block[17] + (block[18] << 8);
63 	boot->bpbSectors = block[19] + (block[20] << 8);
64 	boot->bpbMedia = block[21];
65 	boot->bpbFATsmall = block[22] + (block[23] << 8);
66 	boot->SecPerTrack = block[24] + (block[25] << 8);
67 	boot->bpbHeads = block[26] + (block[27] << 8);
68 	boot->bpbHiddenSecs = block[28] + (block[29] << 8) +
69 	    (block[30] << 16) + (block[31] << 24);
70 	boot->bpbHugeSectors = block[32] + (block[33] << 8) +
71 	    (block[34] << 16) + (block[35] << 24);
78 		boot->FATsecs = block[36] + (block[37] << 8)
79 				+ (block[38] << 16) + (block[39] << 24);
80 		if (block[40] & 0x80)
81 			boot->ValidFat = block[40] & 0x0f;
84 		if (block[42] || block[43]) {
87 			       block[43], block[42]);
90 		boot->bpbRootClust = block[44] + (block[45] << 8)
91 			       + (block[46] << 16) + (block[47] << 24);
92 		boot->bpbFSInfo = block[48] + (block[49] << 8);
93 		boot->bpbBackup = block[50] + (block[51] << 8);
98 			perr("could not read fsinfo block");
111 			pwarn("Invalid signature in fsinfo block\n");
149 		backup[65] = block[65];				/* XXX */
150 		if (memcmp(block + 11, backup + 11, 79)) {
160 			pfatal("backup (block %d) mismatch with primary bootblock:\n",
163 				if (block[i] != backup[i])
165 					       i, block[i], backup[i]);
233 	if (block[dirtybyte] & 0x01) {
239 		block[dirtybyte] &= ~0x01;
241 			|| write(dosfs, block, sizeof block) != sizeof block) {
242 			perr("could not write boot block");
259 		perr("could not read fsinfo block");
281 	 * support for FAT32) doesn't maintain the FSINFO block
284 	 * Therefor, we handle the FSINFO block only informally,