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Diffstat (limited to 'sbin/fsck_msdosfs/boot.c')
-rw-r--r--sbin/fsck_msdosfs/boot.c268
1 files changed, 268 insertions, 0 deletions
diff --git a/sbin/fsck_msdosfs/boot.c b/sbin/fsck_msdosfs/boot.c
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index 000000000000..5c1ae5ad1cc3
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+++ b/sbin/fsck_msdosfs/boot.c
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+/*
+ * Copyright (C) 1995, 1997 Wolfgang Solfrank
+ * Copyright (c) 1995 Martin Husemann
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by Martin Husemann
+ * and Wolfgang Solfrank.
+ * 4. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+
+#include <sys/cdefs.h>
+#ifndef lint
+__RCSID("$NetBSD: boot.c,v 1.5 1997/10/17 11:19:23 ws Exp $");
+static const char rcsid[] =
+ "$FreeBSD$";
+#endif /* not lint */
+
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include "ext.h"
+#include "fsutil.h"
+
+int
+readboot(dosfs, boot)
+ int dosfs;
+ struct bootblock *boot;
+{
+ u_char block[DOSBOOTBLOCKSIZE];
+ u_char fsinfo[2 * DOSBOOTBLOCKSIZE];
+ u_char backup[DOSBOOTBLOCKSIZE];
+ int ret = FSOK;
+
+ if (read(dosfs, block, sizeof block) < sizeof block) {
+ perror("could not read boot block");
+ return FSFATAL;
+ }
+
+ if (block[510] != 0x55 || block[511] != 0xaa) {
+ pfatal("Invalid signature in boot block: %02x%02x", block[511], block[510]);
+ return FSFATAL;
+ }
+
+ memset(boot, 0, sizeof *boot);
+ boot->ValidFat = -1;
+
+ /* decode bios parameter block */
+ boot->BytesPerSec = block[11] + (block[12] << 8);
+ boot->SecPerClust = block[13];
+ boot->ResSectors = block[14] + (block[15] << 8);
+ boot->FATs = block[16];
+ boot->RootDirEnts = block[17] + (block[18] << 8);
+ boot->Sectors = block[19] + (block[20] << 8);
+ boot->Media = block[21];
+ boot->FATsmall = block[22] + (block[23] << 8);
+ boot->SecPerTrack = block[24] + (block[25] << 8);
+ boot->Heads = block[26] + (block[27] << 8);
+ boot->HiddenSecs = block[28] + (block[29] << 8) + (block[30] << 16) + (block[31] << 24);
+ boot->HugeSectors = block[32] + (block[33] << 8) + (block[34] << 16) + (block[35] << 24);
+
+ boot->FATsecs = boot->FATsmall;
+
+ if (!boot->RootDirEnts)
+ boot->flags |= FAT32;
+ if (boot->flags & FAT32) {
+ boot->FATsecs = block[36] + (block[37] << 8)
+ + (block[38] << 16) + (block[39] << 24);
+ if (block[40] & 0x80)
+ boot->ValidFat = block[40] & 0x0f;
+
+ /* check version number: */
+ if (block[42] || block[43]) {
+ /* Correct? XXX */
+ pfatal("Unknown filesystem version: %x.%x",
+ block[43], block[42]);
+ return FSFATAL;
+ }
+ boot->RootCl = block[44] + (block[45] << 8)
+ + (block[46] << 16) + (block[47] << 24);
+ boot->FSInfo = block[48] + (block[49] << 8);
+ boot->Backup = block[50] + (block[51] << 8);
+
+ if (lseek(dosfs, boot->FSInfo * boot->BytesPerSec, SEEK_SET)
+ != boot->FSInfo * boot->BytesPerSec
+ || read(dosfs, fsinfo, sizeof fsinfo)
+ != sizeof fsinfo) {
+ perror("could not read fsinfo block");
+ return FSFATAL;
+ }
+ if (memcmp(fsinfo, "RRaA", 4)
+ || memcmp(fsinfo + 0x1e4, "rrAa", 4)
+ || fsinfo[0x1fc]
+ || fsinfo[0x1fd]
+ || fsinfo[0x1fe] != 0x55
+ || fsinfo[0x1ff] != 0xaa
+ || fsinfo[0x3fc]
+ || fsinfo[0x3fd]
+ || fsinfo[0x3fe] != 0x55
+ || fsinfo[0x3ff] != 0xaa) {
+ pwarn("Invalid signature in fsinfo block");
+ if (ask(0, "fix")) {
+ memcpy(fsinfo, "RRaA", 4);
+ memcpy(fsinfo + 0x1e4, "rrAa", 4);
+ fsinfo[0x1fc] = fsinfo[0x1fd] = 0;
+ fsinfo[0x1fe] = 0x55;
+ fsinfo[0x1ff] = 0xaa;
+ fsinfo[0x3fc] = fsinfo[0x3fd] = 0;
+ fsinfo[0x3fe] = 0x55;
+ fsinfo[0x3ff] = 0xaa;
+ if (lseek(dosfs, boot->FSInfo * boot->BytesPerSec, SEEK_SET)
+ != boot->FSInfo * boot->BytesPerSec
+ || write(dosfs, fsinfo, sizeof fsinfo)
+ != sizeof fsinfo) {
+ perror("Unable to write FSInfo");
+ return FSFATAL;
+ }
+ ret = FSBOOTMOD;
+ } else
+ boot->FSInfo = 0;
+ }
+ if (boot->FSInfo) {
+ boot->FSFree = fsinfo[0x1e8] + (fsinfo[0x1e9] << 8)
+ + (fsinfo[0x1ea] << 16)
+ + (fsinfo[0x1eb] << 24);
+ boot->FSNext = fsinfo[0x1ec] + (fsinfo[0x1ed] << 8)
+ + (fsinfo[0x1ee] << 16)
+ + (fsinfo[0x1ef] << 24);
+ }
+
+ if (lseek(dosfs, boot->Backup * boot->BytesPerSec, SEEK_SET)
+ != boot->Backup * boot->BytesPerSec
+ || read(dosfs, backup, sizeof backup) != sizeof backup) {
+ perror("could not read backup bootblock");
+ return FSFATAL;
+ }
+ if (memcmp(block, backup, DOSBOOTBLOCKSIZE)) {
+ /* Correct? XXX */
+ pfatal("backup doesn't compare to primary bootblock");
+ return FSFATAL;
+ }
+ /* Check backup FSInfo? XXX */
+ }
+
+ boot->ClusterOffset = (boot->RootDirEnts * 32 + boot->BytesPerSec - 1)
+ / boot->BytesPerSec
+ + boot->ResSectors
+ + boot->FATs * boot->FATsecs
+ - CLUST_FIRST * boot->SecPerClust;
+
+ if (boot->BytesPerSec % DOSBOOTBLOCKSIZE != 0) {
+ pfatal("Invalid sector size: %u", boot->BytesPerSec);
+ return FSFATAL;
+ }
+ if (boot->SecPerClust == 0) {
+ pfatal("Invalid cluster size: %u", boot->SecPerClust);
+ return FSFATAL;
+ }
+ if (boot->Sectors) {
+ boot->HugeSectors = 0;
+ boot->NumSectors = boot->Sectors;
+ } else
+ boot->NumSectors = boot->HugeSectors;
+ boot->NumClusters = (boot->NumSectors - boot->ClusterOffset) / boot->SecPerClust;
+
+ if (boot->flags&FAT32)
+ boot->ClustMask = CLUST32_MASK;
+ else if (boot->NumClusters < (CLUST_RSRVD&CLUST12_MASK))
+ boot->ClustMask = CLUST12_MASK;
+ else if (boot->NumClusters < (CLUST_RSRVD&CLUST16_MASK))
+ boot->ClustMask = CLUST16_MASK;
+ else {
+ pfatal("Filesystem too big (%u clusters) for non-FAT32 partition",
+ boot->NumClusters);
+ return FSFATAL;
+ }
+
+ switch (boot->ClustMask) {
+ case CLUST32_MASK:
+ boot->NumFatEntries = (boot->FATsecs * boot->BytesPerSec) / 4;
+ break;
+ case CLUST16_MASK:
+ boot->NumFatEntries = (boot->FATsecs * boot->BytesPerSec) / 2;
+ break;
+ default:
+ boot->NumFatEntries = (boot->FATsecs * boot->BytesPerSec * 2) / 3;
+ break;
+ }
+
+ if (boot->NumFatEntries < boot->NumClusters) {
+ pfatal("FAT size too small, %u entries won't fit into %u sectors\n",
+ boot->NumClusters, boot->FATsecs);
+ return FSFATAL;
+ }
+ boot->ClusterSize = boot->BytesPerSec * boot->SecPerClust;
+
+ boot->NumFiles = 1;
+ boot->NumFree = 0;
+
+ return ret;
+}
+
+int
+writefsinfo(dosfs, boot)
+ int dosfs;
+ struct bootblock *boot;
+{
+ u_char fsinfo[2 * DOSBOOTBLOCKSIZE];
+
+ if (lseek(dosfs, boot->FSInfo * boot->BytesPerSec, SEEK_SET)
+ != boot->FSInfo * boot->BytesPerSec
+ || read(dosfs, fsinfo, sizeof fsinfo) != sizeof fsinfo) {
+ perror("could not read fsinfo block");
+ return FSFATAL;
+ }
+ fsinfo[0x1e8] = (u_char)boot->FSFree;
+ fsinfo[0x1e9] = (u_char)(boot->FSFree >> 8);
+ fsinfo[0x1ea] = (u_char)(boot->FSFree >> 16);
+ fsinfo[0x1eb] = (u_char)(boot->FSFree >> 24);
+ fsinfo[0x1ec] = (u_char)boot->FSNext;
+ fsinfo[0x1ed] = (u_char)(boot->FSNext >> 8);
+ fsinfo[0x1ee] = (u_char)(boot->FSNext >> 16);
+ fsinfo[0x1ef] = (u_char)(boot->FSNext >> 24);
+ if (lseek(dosfs, boot->FSInfo * boot->BytesPerSec, SEEK_SET)
+ != boot->FSInfo * boot->BytesPerSec
+ || write(dosfs, fsinfo, sizeof fsinfo)
+ != sizeof fsinfo) {
+ perror("Unable to write FSInfo");
+ return FSFATAL;
+ }
+ /*
+ * Technically, we should return FSBOOTMOD here.
+ *
+ * However, since Win95 OSR2 (the first M$ OS that has
+ * support for FAT32) doesn't maintain the FSINFO block
+ * correctly, it has to be fixed pretty often.
+ *
+ * Therefor, we handle the FSINFO block only informally,
+ * fixing it if neccessary, but otherwise ignoring the
+ * fact that it was incorrect.
+ */
+ return 0;
+}