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Fixed root directory check to ensure we don't select a disk format with too few root directory entries

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This commit is contained in:
Jeff Parsons 2017-06-19 18:12:33 -07:00 • committed by Jeff Parsons
commit 4e0d3d46da
2 changed files with 23 additions and 27 deletions
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49
modules/diskdump/lib/diskdump.js
View file

@ -961,13 +961,13 @@ DiskDump.updateManifest = function(disk, sManifestFile, sDiskPath, sOutputFile,
}
if (!sIDDisk) {
for (i = 1; i < 1000; i++) {
for (i = 1; i < 10000; i++) {
sIDDisk = i.toString();
if (sIDDisk.length < 2) sIDDisk = '0' + sIDDisk;
sIDDisk = "disk" + sIDDisk;
if (sXML.indexOf(' id="' + sIDDisk + '"') < 0) break;
}
if (i == 1000) {
if (i == 10000) {
err = new Error("manifest already contains " + i + " disks");
}
}
@ -2408,24 +2408,25 @@ DiskDump.prototype.buildImageFromFiles = function(aFiles, done)
*/
for (var iBPB = 0; iBPB < DiskDump.aDefaultBPBs.length; iBPB++) {
/*
* Use slice() to copy the default BPB, as a precaution (to avoid any changes to the default).
* Use slice() to copy the BPB, to ensure we don't alter the original.
*/
abBoot = DiskDump.aDefaultBPBs[iBPB].slice();
/*
* If this BPB is for a hard drive but a disk size was not specified, skip it.
*/
if ((abBoot[0x15] == 0xF8) != (this.kbTarget >= 10000)) continue;
cbSector = abBoot[0x0B] | (abBoot[0x0C] << 8);
cSectorsPerCluster = abBoot[0x0D];
if ((abBoot[DiskAPI.BPB.MEDIA_TYPE] == DiskAPI.FAT.MEDIA_FIXED) != (this.kbTarget >= 10000)) continue;
cRootEntries = abBoot[DiskAPI.BPB.ROOT_DIRENTS] | (abBoot[DiskAPI.BPB.ROOT_DIRENTS + 1] << 8);
if (aFiles.length > cRootEntries) continue;
cbSector = abBoot[DiskAPI.BPB.SECTOR_BYTES] | (abBoot[DiskAPI.BPB.SECTOR_BYTES + 1] << 8);
cSectorsPerCluster = abBoot[DiskAPI.BPB.CLUSTER_SECS];
cbCluster = cbSector * cSectorsPerCluster;
cFATs = abBoot[0x10];
cFATSectors = abBoot[0x16] | (abBoot[0x17] << 8);
cRootEntries = abBoot[0x11] | (abBoot[0x12] << 8);
cRootSectors = (((cRootEntries * 0x20) + cbSector - 1) / cbSector) | 0;
cTotalSectors = abBoot[0x13] | (abBoot[0x14] << 8);
cSectorsPerTrack = abBoot[0x18] | (abBoot[0x19] << 8);
cHeads = abBoot[0x1A] | (abBoot[0x1B] << 8);
cDataSectors = cTotalSectors - cRootSectors - cFATs * cFATSectors + 1;
cFATs = abBoot[DiskAPI.BPB.TOTAL_FATS];
cFATSectors = abBoot[DiskAPI.BPB.FAT_SECS] | (abBoot[DiskAPI.BPB.FAT_SECS + 1] << 8);
cRootSectors = (((cRootEntries * DiskAPI.DIRENT.LENGTH) + cbSector - 1) / cbSector) | 0;
cTotalSectors = abBoot[DiskAPI.BPB.TOTAL_SECS] | (abBoot[DiskAPI.BPB.TOTAL_SECS + 1] << 8);
cSectorsPerTrack = abBoot[DiskAPI.BPB.TRACK_SECS] | (abBoot[DiskAPI.BPB.TRACK_SECS + 1] << 8);
cHeads = abBoot[DiskAPI.BPB.TOTAL_HEADS] | (abBoot[DiskAPI.BPB.TOTAL_HEADS + 1] << 8);
cDataSectors = cTotalSectors - (cRootSectors + cFATs * cFATSectors + 1);
cbAvail = cDataSectors * cbSector;
if (!nTargetSectors) {
if (cbTotal <= cbAvail) {
@ -2441,13 +2442,7 @@ DiskDump.prototype.buildImageFromFiles = function(aFiles, done)
}
if (iBPB == DiskDump.aDefaultBPBs.length) {
err = new Error("file(s) too large for disk image (" + cbTotal + " vs. " + cbAvail + " bytes)");
done(err);
return false;
}
if (aFiles.length > cRootEntries) {
err = new Error("too many files for disk image (" + aFiles.length + " vs. " + cRootEntries + " max)");
err = new Error("too many file(s) for disk image (" + aFiles.length + " files, " + cbTotal + " bytes)");
done(err);
return false;
}
@ -2481,8 +2476,8 @@ DiskDump.prototype.buildImageFromFiles = function(aFiles, done)
/*
* Output a boot sector.
*/
abBoot[DiskAPI.BOOT.SIG_OFFSET] = 0x55;
abBoot[DiskAPI.BOOT.SIG_OFFSET + 1] = 0xAA;
abBoot[DiskAPI.BOOT.SIG_OFFSET] = DiskAPI.BOOT.SIGNATURE & 0xff; // 0x55
abBoot[DiskAPI.BOOT.SIG_OFFSET + 1] = (DiskAPI.BOOT.SIGNATURE >> 8) & 0xff; // 0xAA
abSector = this.buildData(cbSector, abBoot);
offDisk += this.copyData(offDisk, abSector);
@ -2493,7 +2488,7 @@ DiskDump.prototype.buildImageFromFiles = function(aFiles, done)
* BPB at offset 0x15. For old BPB-less diskettes, this is where you must look for the media type.
*/
var abFAT = [];
this.buildFATEntry(abFAT, 0, abBoot[0x15] | 0xF00);
this.buildFATEntry(abFAT, 0, abBoot[DiskAPI.BPB.MEDIA_TYPE] | 0xF00);
this.buildFATEntry(abFAT, 1, 0xFFF);
this.buildFAT(abFAT, aFiles, 2, cbCluster);
@ -2516,10 +2511,10 @@ DiskDump.prototype.buildImageFromFiles = function(aFiles, done)
* PC-DOS 1.0 requires ALL unused directory entries to start with 0xE5; 0x00 isn't good enough,
* so we must loop through all the remaining directory entries and zap them with 0xE5.
*/
var offRoot = cEntries * 32;
var offRoot = cEntries * DiskAPI.DIRENT.LENGTH;
while (cEntries++ < cRootEntries) {
abRoot[offRoot] = 0xE5;
offRoot += 32;
abRoot[offRoot] = DiskAPI.DIRENT.INVALID; // 0xE5
offRoot += DiskAPI.DIRENT.LENGTH; // 0x20 (32)
}
/*

1
modules/shared/lib/diskapi.js
View file

@ -186,6 +186,7 @@ DiskAPI.FAT = {
MEDIA_360KB: 0xFD, // 5.25-inch, 2-sided, 9-sector, 40-track
MEDIA_720KB: 0xF9, // 3.5-inch, 2-sided, 9-sector, 80-track
MEDIA_1200KB: 0xF9, // 3.5-inch, 2-sided, 15-sector, 80-track
MEDIA_FIXED: 0xF8, // fixed disk (aka hard drive)
MEDIA_1440KB: 0xF0, // 3.5-inch, 2-sided, 18-sector, 80-track
MEDIA_2880KB: 0xF0 // 3.5-inch, 2-sided, 36-sector, 80-track
};