example with FAT16 and 32k cluster size, a simple write of 32k will crash libfat.
i traced down the problem to be in the last commit, reverting one change fixes it, see below:
is this a valid fix or is there something else to it?
--- libfat-105-x/source/fatfile.c 2009-10-08 22:06:48.000000000 +0200
+++ libfat/source/fatfile.c 2009-10-22 03:15:50.744005200 +0200
@@ -757,12 +757,14 @@
}
}
- size_t chunkSize = partition->bytesPerCluster;
remain);
// Write whole clusters
while ((remain >= partition->bytesPerCluster) && flagNoError) {
uint32_t chunkEnd;
uint32_t nextChunkStart = position.cluster;
+ size_t chunkSize = 0;
do {
chunkEnd = nextChunkStart;
libfat crash if cluster size equal and aligned to write size
Re: libfat crash if cluster size equal and aligned to write size
ah, the fix is not proper, it causes all files to allocate more clusters than used
so the problem remains
so the problem remains
Re: libfat crash if cluster size equal and aligned to write size
Ok i think i made a proper fix that solves both problems that i posted. Should i go ahead and post the diff here? It's not as short as the previous one and i don't know if this is the right place and if anyone is interested? Do only I get corrupted files using libfat?
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Re: libfat crash if cluster size equal and aligned to write size
Add it to the patch tracker @ http://sourceforge.net/tracker/?group_i ... tid=668553
I was just about to have a look at that but if you've already solved it then I can move on to something else![Smile :)](./images/smilies/icon_smile.gif)
I was just about to have a look at that but if you've already solved it then I can move on to something else
![Smile :)](./images/smilies/icon_smile.gif)
Re: libfat crash if cluster size equal and aligned to write size
ok, submitted.
https://sourceforge.net/tracker/?func=d ... tid=668553
it of course needs a thorough review and testing.
also i made a wrapper for linux to use libfat in a user process which i used to test and debug the code, do you want me to upload that too somewhere?
https://sourceforge.net/tracker/?func=d ... tid=668553
it of course needs a thorough review and testing.
also i made a wrapper for linux to use libfat in a user process which i used to test and debug the code, do you want me to upload that too somewhere?
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Re: libfat crash if cluster size equal and aligned to write size
Good catch on the bug, thanks for the patch. It's been committed and released now in libfat 1.0.6.
It would be interesting to see your wrapper for testing, mostly I test on hardware atm.
It would be interesting to see your wrapper for testing, mostly I test on hardware atm.
Re: libfat crash if cluster size equal and aligned to write size
Ok, you can find the linux wrapper for testing here:
http://cfg-loader.googlecode.com/files/ ... -linux.tgz
I have already updated it to version 1.0.6 of libfat.
To try it out run this:
cd libfat-106-linux/source
make
cd ../test
make
sh runtest.sh
runtest.sh is this:
dd if=/dev/zero of=fat.dat bs=1M count=10
mkdosfs fat.dat
file fat.dat
./testfat
dosfsck fat.dat
exit
# optional:
mkdir mnt
mount fat.dat mnt -o loop
ls -l mnt
umount mnt
rmdir mnt
hope it helps.
Oh and almost forgot, the dosfsck will complain with:
dosfsck 3.0.1, 23 Nov 2008, FAT32, LFN
FATs differ but appear to be intact. Use which FAT ?
1) Use first FAT
2) Use second FAT
? 1
Leaving file system unchanged.
fat.dat: 11 files, 1164/5101 clusters
Which is another little issue that needs fixing, but this one is not so critical.
http://cfg-loader.googlecode.com/files/ ... -linux.tgz
I have already updated it to version 1.0.6 of libfat.
To try it out run this:
cd libfat-106-linux/source
make
cd ../test
make
sh runtest.sh
runtest.sh is this:
dd if=/dev/zero of=fat.dat bs=1M count=10
mkdosfs fat.dat
file fat.dat
./testfat
dosfsck fat.dat
exit
# optional:
mkdir mnt
mount fat.dat mnt -o loop
ls -l mnt
umount mnt
rmdir mnt
hope it helps.
Oh and almost forgot, the dosfsck will complain with:
dosfsck 3.0.1, 23 Nov 2008, FAT32, LFN
FATs differ but appear to be intact. Use which FAT ?
1) Use first FAT
2) Use second FAT
? 1
Leaving file system unchanged.
fat.dat: 11 files, 1164/5101 clusters
Which is another little issue that needs fixing, but this one is not so critical.
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