Do you know of any good Buffer inspection library for Node.js?
It would be pretty useful to print out a Buffer along with its utf8 content.
Example:
Byte | HEX | UTF-8 | Name
-----+-----+-------+-----------
0 | 48 | H | UPPER H
1 | 65 | e | LOWER E
2 | 6c | l | LOWER L
3 | 6c | l | LOWER L
4 | 6f | o | LOWER O
5 | 20 | | WHITESPACE
6 | 57 | W | UPPER W
7 | 6f | o | LOWER O
8 | 72 | r | LOWER R
9 | 6c | l | LOWER L
10 | 64 | d | LOWER D
Yesterday I made a simple module called hex. It's like the hxd program. No config necessary, easy to use, for debugging purposes.
var hex = require("hex");
hex(buffer);
Output:
Offset 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
000000 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ
000010 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ
000020 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ
000030 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ
000040 54 41 47 42 72 65 61 6B 69 6E 67 20 54 68 65 20 TAGBreaking The
000050 4C 61 77 00 00 00 00 00 00 00 00 00 00 00 00 00 Law.............
000060 00 4A 75 64 61 73 20 50 72 69 65 73 74 00 00 00 .Judas Priest...
000070 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 42 ...............B
000080 72 69 74 69 73 68 20 53 74 65 65 6C 00 00 00 00 ritish Steel....
000090 00 00 00 00 00 00 00 00 00 00 00 00 00 31 39 38 .............198
0000A0 30 47 72 65 61 74 20 73 6F 6E 67 21 00 00 00 00 0Great song!....
0000B0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 33 89 ..............3.
Related
Background is that I have a log file that contains hex dumps that I want to convert with xxd to get that nice ASCII column that shows possible strings in the binary data.
The log file format looks like this:
My interesting hex dump:
00 53 00 6f 00 6d 00 65 00 20 00 74 00 65 00 78
00 74 00 20 00 65 00 78 00 61 00 6d 00 70 00 6c
00 65 00 20 00 75 00 73 00 69 00 6e 00 67 00 20
00 55 00 54 00 46 00 2d 00 31 00 36 00 20 00 69
00 6e 00 20 00 6f 00 72 00 64 00 65 00 72 00 20
00 74 00 6f 00 20 00 67 00 65 00 74 00 20 00 30
00 78 00 30 00 30 00 20 00 62 00 79 00 74 00 65
00 73 00 2e
Visually selecting the hex dump and do xxd -r -p followed by a xxd -g1 on the result does exactly what I'm aiming for.
However, since the number of dumps I want to convert are quite a few I would rather automate the process.
So I'm using the following substitute command to do the conversion:
:%s/\(\x\{2\} \?\)\{16\}\_.*/\=system('xxd -g1',system('xxd -r -p',submatch(0)))
The expression matches the entire hex dump in the log file. The match is sent to xxd -r -p as stdin and its output is used as stdin for xxd -g1.
Well, that's the idea at least.
The thing is that the above almost works. It produces the following result:
My interesting hex dump:
00000000: 01 53 01 6f 01 6d 01 65 01 20 01 74 01 65 01 78 .S.o.m.e. .t.e.x
00000010: 01 74 01 20 01 65 01 78 01 61 01 6d 01 70 01 6c .t. .e.x.a.m.p.l
00000020: 01 65 01 20 01 75 01 73 01 69 01 6e 01 67 01 20 .e. .u.s.i.n.g.
00000030: 01 55 01 54 01 46 01 2d 01 31 01 36 01 20 01 69 .U.T.F.-.1.6. .i
00000040: 01 6e 01 20 01 6f 01 72 01 64 01 65 01 72 01 20 .n. .o.r.d.e.r.
00000050: 01 74 01 6f 01 20 01 67 01 65 01 74 01 20 01 30 .t.o. .g.e.t. .0
00000060: 01 78 01 30 01 30 01 20 01 62 01 79 01 74 01 65 .x.0.0. .b.y.t.e
00000070: 01 73 01 2e .s..
All 00 bytes have mysteriously transformed into 01.
It should have produced the following:
My interesting hex dump:
00000000: 00 53 00 6f 00 6d 00 65 00 20 00 74 00 65 00 78 .S.o.m.e. .t.e.x
00000010: 00 74 00 20 00 65 00 78 00 61 00 6d 00 70 00 6c .t. .e.x.a.m.p.l
00000020: 00 65 00 20 00 75 00 73 00 69 00 6e 00 67 00 20 .e. .u.s.i.n.g.
00000030: 00 55 00 54 00 46 00 2d 00 31 00 36 00 20 00 69 .U.T.F.-.1.6. .i
00000040: 00 6e 00 20 00 6f 00 72 00 64 00 65 00 72 00 20 .n. .o.r.d.e.r.
00000050: 00 74 00 6f 00 20 00 67 00 65 00 74 00 20 00 30 .t.o. .g.e.t. .0
00000060: 00 78 00 30 00 30 00 20 00 62 00 79 00 74 00 65 .x.0.0. .b.y.t.e
00000070: 00 73 00 2e .s..
What am I not getting here?
Of course I can use macros and other ways of doing this, but I want to understand why my substitution command doesn't do what I expect.
Edit:
For anyone that want to achieve the same thing I provide the substitution expression that works on an entire file. The expression above was only for testing purposes using the log file example also from above.
The one below is the one that performs a correct conversion, modified based on the information Kent provided in his answer.
:%s/\(\(\x\{2\} \)\{16\}\_.\)\+/\=system('xxd -p -r | xxd -g1',submatch(0))
very likely, the problem is string conversion in the system() The input will be converted into a string by vim, so does the output of your first xxd command.
You can try to extract that hex parts into a file. then:
xxd -r -p theFile|vim -
And then calling the system('xxd -g1', alltext), you are gonna get something else than 00 too.
This doesn't work in the same way of a pipe (xxd ...|xxd...). But unfortunately, the system() function doesn't accept pipes.
If you want to fix your :s command, you need to call systemlist() on your first xxd call to get the data in binary format, then pass it to the 2nd xxd:
:%s/\(\x\{2\} \?\)\{16\}\_.*/\=system('xxd -g1',systemlist('xxd -r -p',submatch(0)))
The cmd above will generate the 00s. since there is no string conversion.
However, when working with some data format other than plain string, perhaps we can use filters instead of calling system(). It would be a lot eaiser. For your example:
2,$!xxd -r -p|xxd -g1
I'm trying to modify buffers, however when modifying them I wish them to be in utf-8 so I attempt to do this via myBuffer.toString('utf8') however if I make no changes and attempt to convert it back via Buffer.from(myBuffer, 'utf8'), I am presented with a completely new buffer on occasions.
These occasions seem to be when parsing an image file, instead of a html file.
My next step was to accept a bug or erroneous behaviour by comparing the two buffers using the following code:
//myBuffer is the buffer is wish to attempt to modify
let testParse = Buffer.from(myBuffer.toString('utf8'), 'utf8');
let editable = Buffer.compare(myBuffer, testParse);
console.log(myBuffer);
console.log(testParse);
console.log(editable);
The following snippet however refuses to work and editable is always -1 here is an example output:
<Buffer 89 50 4e 47 0d 0a 1a 0a 00 00 00 0d 49 48 44 52 00 00 01 10 00 00 00 5c 08 02 00 00 00 29 85 7d e1 00 00 15 31 49 44 41 54 78 01 ed 5d 05 94 db c8 b2 ... >
<Buffer ef bf bd 50 4e 47 0d 0a 1a 0a 00 00 00 0d 49 48 44 52 00 00 01 10 00 00 00 5c 08 02 00 00 00 29 ef bf bd 7d ef bf bd 00 00 15 31 49 44 41 54 78 01 ef ... >
-1
As you can see the buffers are completely different however returns -1
another example where the buffers are both equal:
<Buffer 3c 21 64 6f 63 74 79 70 65 20 68 74 6d 6c 3e 3c 68 74 6d 6c 20 69 74 65 6d 73 63 6f 70 65 3d 22 22 20 69 74 65 6d 74 79 70 65 3d 22 68 74 74 70 3a 2f ... >
<Buffer 3c 21 64 6f 63 74 79 70 65 20 68 74 6d 6c 3e 3c 68 74 6d 6c 20 69 74 65 6d 73 63 6f 70 65 3d 22 22 20 69 74 65 6d 74 79 70 65 3d 22 68 74 74 70 3a 2f ... >
-1
As you can see both buffers are equal and -1 is still returned.
So my question is, what am I doing wrong so that the buffers cannot be compared properly? Any suggestions/criticism are welcome.
You have to compare in the same encoding :
//:Buffer Comparison
const fs = require('fs')
fs.readFile(__dirname+"/test.jpg",(e,buffer)=>{
let testParse = Buffer.from(buffer.toString('utf8'), 'utf8');
let editable = Buffer.compare(buffer, testParse);
console.log("----: wrong method :----")
console.log(buffer);
console.log(testParse);
console.log(editable);
// You have to compare them in the same encoding :
console.log("----: right method :----")
let goodParse = Buffer.from(buffer.toString('utf8'));
let editable2 = goodParse.compare(Buffer.from(buffer.toString('utf8')));
console.log(buffer);
console.log(goodParse);
console.log(editable2);
})
As you can see, we load an image as a buffer, then it is parsed into utf8, so if you modify it, and then want to compare it to the original buffer. Since the modified was parsed to utf8 the original must also be parsed to utf8 in the moment of the comparison.
I hope you understand that explanation.
Console output:
----: wrong method :----
<Buffer ff d8 ff e0 00 10 4a 46 49 46 00 01 01 00 00 01 00 01 00 00 ff db 00 43 00 08 06 06 07 06 05 08 07 07 07 09 09 08 0a 0c 14 0d 0c 0b 0b 0c 19 12 13 0f ... >
<Buffer ef bf bd ef bf bd ef bf bd ef bf bd 00 10 4a 46 49 46 00 01 01 00 00 01 00 01 00 00 ef bf bd ef bf bd 00 43 00 08 06 06 07 06 05 08 07 07 07 09 09 08 ... >
1
----: right method :----
<Buffer ff d8 ff e0 00 10 4a 46 49 46 00 01 01 00 00 01 00 01 00 00 ff db 00 43 00 08 06 06 07 06 05 08 07 07 07 09 09 08 0a 0c 14 0d 0c 0b 0b 0c 19 12 13 0f ... >
<Buffer ef bf bd ef bf bd ef bf bd ef bf bd 00 10 4a 46 49 46 00 01 01 00 00 01 00 01 00 00 ef bf bd ef bf bd 00 43 00 08 06 06 07 06 05 08 07 07 07 09 09 08 ... >
0
I would like to know to recover deleted file from FAT. I created fat.img as below.
cd /tmp
dd if=/dev/zero of=fat.img bs=1024 count=100
mkfs.msdos fat.img
mkdir -p /tmp/fs
sudo mount -t msdos fat.img /tmp/fs -o umask=000,loop
Now i am creating file with some text.
cd/tmp/fs
echo "hello world"> name
Using hexdump to see how it was saved
cd ..
hexdump -C fat.img
00000000 eb 3c 90 6d 6b 66 73 2e 66 61 74 00 02 04 01 00 |.<.mkfs.fat.....|
00000010 02 00 02 c8 00 f8 01 00 20 00 40 00 00 00 00 00 |........ .#.....|
00000020 00 00 00 00 80 01 29 3c 69 e6 fb 4e 4f 20 4e 41 |......)<i..NO NA|
00000030 4d 45 20 20 20 20 46 41 54 31 32 20 20 20 0e 1f |ME FAT12 ..|
00000040 be 5b 7c ac 22 c0 74 0b 56 b4 0e bb 07 00 cd 10 |.[|.".t.V.......|
00000050 5e eb f0 32 e4 cd 16 cd 19 eb fe 54 68 69 73 20 |^..2.......This |
00000060 69 73 20 6e 6f 74 20 61 20 62 6f 6f 74 61 62 6c |is not a bootabl|
00000070 65 20 64 69 73 6b 2e 20 20 50 6c 65 61 73 65 20 |e disk. Please |
00000080 69 6e 73 65 72 74 20 61 20 62 6f 6f 74 61 62 6c |insert a bootabl|
00000090 65 20 66 6c 6f 70 70 79 20 61 6e 64 0d 0a 70 72 |e floppy and..pr|
000000a0 65 73 73 20 61 6e 79 20 6b 65 79 20 74 6f 20 74 |ess any key to t|
000000b0 72 79 20 61 67 61 69 6e 20 2e 2e 2e 20 0d 0a 00 |ry again ... ...|
000000c0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
000001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.|
00000200 f8 ff ff 00 f0 ff 00 00 00 00 00 00 00 00 00 00 |................|
00000210 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00000400 f8 ff ff 00 f0 ff 00 00 00 00 00 00 00 00 00 00 |................|
00000410 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00000600 4e 41 4d 45 20 20 20 20 20 20 20 20 00 00 00 00 |NAME ....|
00000610 00 00 00 00 00 00 21 86 91 4b 03 00 0c 00 00 00 |......!..K......|
00000620 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00004e00 68 65 6c 6c 6f 20 77 6f 72 6c 64 0a 00 00 00 00 |hello world.....|
00004e10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00019000
After deleting file name we can see change in hexdump
00000600 4e 41 4d 45 20 20 20 20 20 20 20 20 00 00 00 00 |.AME ....|
00000610 00 00 00 00 00 00 21 86 91 4b 03 00 0c 00 00 00 |......!..K......|
00000620 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
And here is my question do you have any suggestion how can i change fat.img to .AME to NAME to recovery my file?
how can i change fat.img to .AME to NAME to recovery my file?
The short answer is with dd, an example with the necessary caveats follows below.
Adding to Martin's answer, while manipulating the bytes to restore the file within the floppy image is a relatively straight-forward proposition with dd, computing where and what within the file allocation table(s) needs to be restored is the challenge. Walking through the use of dd to restore the file itself, knowing what bytes need attention is illustrated by the following example.
Creating a floppy image to work with saves you from having to experiment on your actual image. Simply duplicate your image you wish to work with, or create a new one within a file on your hard drive. You can do that easily with mkfs.msdos (adjust the filesystem type as needed), and then mount the file within your filesystem as follows, e.g.
$ mkfs.msdos -C /home/david/tmp/tt/floppy_144.img 1440
$ sudo mount /home/david/tmp/tt/floppy_144.img /mnt/fd
Now let's add the NAME file:
$ echo "hello world" > NAME
$ sudo cp -a NAME /mnt/fd
$ ls -l /mnt/fd
total 1
-rwxr-xr-x 1 root root 12 Dec 17 13:55 NAME
$ cat /mnt/fd/NAME
hello world
Before deleting the file from your image, hexdump the contents so you can see exactly what needs to be restored. (this is what you must compute in order to know where and what to restore with your original image, you will need to consult a reference for the precise filesystem at issue)
$ hexdump -C floppy_144.img >flpwname.txt
Now delete the file from your image and again save a hexdump showing the changes.
$ sudo rm /mnt/fd/NAME
$ hexdump -C floppy_144.img >flpwoname.txt
Now you can examing the difference with diff. What you find is you must restore more than the first name of the file that was deleted, you will need to restore the file allocation table entries so that the restored file can again be located within the filesystem (both copies of the FAT), e.g.
$ diff flpwname.txt flpwoname.txt
16c16
< 00000200 f0 ff ff 00 f0 ff 00 00 00 00 00 00 00 00 00 00 |................|
---
> 00000200 f0 ff ff 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
19c19
< 00001400 f0 ff ff 00 f0 ff 00 00 00 00 00 00 00 00 00 00 |................|
---
> 00001400 f0 ff ff 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
22c22
< 00002600 4e 41 4d 45 20 20 20 20 20 20 20 20 00 00 fa 9e |NAME ....|
---
> 00002600 e5 41 4d 45 20 20 20 20 20 20 20 20 00 00 fa 9e |.AME ....|
Note above the entries for the file allocation table(s) at 0x204 and 0x1404 were zeroed when the file was removed. Restoring the bytes to the original can be easily done with dd but pay attention to your options. Specifically your block size (bs), output block size (obs), count and seek must all be in bytes (specified by appending c) to the number and you must set the notrunc conversion option to prevent truncating your image following the changes you make. Lastly, all sizes must be specified in decimal not hexadecimal.
Further, if you are using bash, you can use a process redirection to specify the bytes to replace (e.g. if=<(printf "\xf0\xff") to write the hex bytes f0 and ff), otherwise, you will have to prepare input files containing your replacement strings. The dd commands to restore the FAT and the first character of the filename are fairly simple (consult man 1 dd for option explanation).
Below we restore the first copy of the FAT, then the second, and finally restore the first character of the filename. The seek (offset) values are just those provided by hexdump converted to decimal. (you should unmount your filesystem before making changes. you can make changes while your floppy image is mounted, but they won't be reflected until you remount)
$ sudo umount /mnt/fd
$ dd if=<(printf "\xf0\xff") of=floppy_144.img \
bs=1c obs=1c count=2c seek=516c conv=notrunc
$ dd if=<(printf "\xf0\xff") of=floppy_144.img \
bs=1c obs=1c count=2c seek=5124c conv=notrunc
$ dd if=<(printf "N") of=floppy_144.img \
bs=1c obs=1c count=1c seek=9728c conv=notrunc
Now you can create a hexdump of the repaired floppy image and compare that to the original. If all has gone as it should, there will be no difference.
$ hexdump -C floppy_144.img >flprepair.txt
$ diff flpwname.txt flprepair.txt
Finally, just remount your filesystem and confirm the file has been restored.
$ sudo mount /home/david/tmp/tt/floppy_144.img /mnt/fd
$ ls -l /mnt/fd
total 1
-rwxr-xr-x 1 root root 12 Dec 17 13:55 NAME
$ cat /mnt/fd/NAME
hello world
That's it. I hope this is what you were looking for. There are a number of tools that automate this process for you, but dd and a pencil and paper can get you by.
The full hexdumps follow for completeness:
Original/Restored
$ cat flpwname.txt
00000000 eb 3c 90 6d 6b 66 73 2e 66 61 74 00 02 01 01 00 |.<.mkfs.fat.....|
00000010 02 e0 00 40 0b f0 09 00 12 00 02 00 00 00 00 00 |...#............|
00000020 00 00 00 00 00 01 29 2c 72 18 ba 4e 4f 20 4e 41 |......),r..NO NA|
00000030 4d 45 20 20 20 20 46 41 54 31 32 20 20 20 0e 1f |ME FAT12 ..|
00000040 be 5b 7c ac 22 c0 74 0b 56 b4 0e bb 07 00 cd 10 |.[|.".t.V.......|
00000050 5e eb f0 32 e4 cd 16 cd 19 eb fe 54 68 69 73 20 |^..2.......This |
00000060 69 73 20 6e 6f 74 20 61 20 62 6f 6f 74 61 62 6c |is not a bootabl|
00000070 65 20 64 69 73 6b 2e 20 20 50 6c 65 61 73 65 20 |e disk. Please |
00000080 69 6e 73 65 72 74 20 61 20 62 6f 6f 74 61 62 6c |insert a bootabl|
00000090 65 20 66 6c 6f 70 70 79 20 61 6e 64 0d 0a 70 72 |e floppy and..pr|
000000a0 65 73 73 20 61 6e 79 20 6b 65 79 20 74 6f 20 74 |ess any key to t|
000000b0 72 79 20 61 67 61 69 6e 20 2e 2e 2e 20 0d 0a 00 |ry again ... ...|
000000c0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
000001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.|
00000200 f0 ff ff 00 f0 ff 00 00 00 00 00 00 00 00 00 00 |................|
00000210 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00001400 f0 ff ff 00 f0 ff 00 00 00 00 00 00 00 00 00 00 |................|
00001410 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00002600 4e 41 4d 45 20 20 20 20 20 20 20 20 00 00 fa 9e |NAME ....|
00002610 91 4b 91 4b 00 00 f5 9e 91 4b 03 00 0c 00 00 00 |.K.K.....K......|
00002620 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00004400 68 65 6c 6c 6f 20 77 6f 72 6c 64 0a 00 00 00 00 |hello world.....|
00004410 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00168000
After NAME Deletion
$ cat flpwoname.txt
00000000 eb 3c 90 6d 6b 66 73 2e 66 61 74 00 02 01 01 00 |.<.mkfs.fat.....|
00000010 02 e0 00 40 0b f0 09 00 12 00 02 00 00 00 00 00 |...#............|
00000020 00 00 00 00 00 01 29 2c 72 18 ba 4e 4f 20 4e 41 |......),r..NO NA|
00000030 4d 45 20 20 20 20 46 41 54 31 32 20 20 20 0e 1f |ME FAT12 ..|
00000040 be 5b 7c ac 22 c0 74 0b 56 b4 0e bb 07 00 cd 10 |.[|.".t.V.......|
00000050 5e eb f0 32 e4 cd 16 cd 19 eb fe 54 68 69 73 20 |^..2.......This |
00000060 69 73 20 6e 6f 74 20 61 20 62 6f 6f 74 61 62 6c |is not a bootabl|
00000070 65 20 64 69 73 6b 2e 20 20 50 6c 65 61 73 65 20 |e disk. Please |
00000080 69 6e 73 65 72 74 20 61 20 62 6f 6f 74 61 62 6c |insert a bootabl|
00000090 65 20 66 6c 6f 70 70 79 20 61 6e 64 0d 0a 70 72 |e floppy and..pr|
000000a0 65 73 73 20 61 6e 79 20 6b 65 79 20 74 6f 20 74 |ess any key to t|
000000b0 72 79 20 61 67 61 69 6e 20 2e 2e 2e 20 0d 0a 00 |ry again ... ...|
000000c0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
000001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.|
00000200 f0 ff ff 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
00000210 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00001400 f0 ff ff 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
00001410 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00002600 e5 41 4d 45 20 20 20 20 20 20 20 20 00 00 fa 9e |.AME ....|
00002610 91 4b 91 4b 00 00 f5 9e 91 4b 03 00 0c 00 00 00 |.K.K.....K......|
00002620 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00004400 68 65 6c 6c 6f 20 77 6f 72 6c 64 0a 00 00 00 00 |hello world.....|
00004410 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00168000
At mount time JFFS2 CLEANMARKER size change from default 0x0C (12B) to 0x0200 (512B).
I saw this behaviour when I mount my test image on target hw (NOR) and file system size increased in crazy way when I copy any file to it.
Test bench
I create a file with 512kB of "aa55" only for reference and with it the JFFS2 file system uncompressed image was created (erase block 128kB page 4kB)
dd if=<(yes $'\xaa55' |tr -d "\n") of=firma_512kB.txt bs=1024 count=512
mkdir firma/
cp firma
cp firma_512kB.txt firma/
sudo mkfs.jffs2 -v -o firma_512.jffs2 -e 0x20000 -s 0x1000 -m none -d firma/
On target the image was copied to mtd14. (It was erased previously. Look that CLEANMARKER has 0x0c size)
flash_eraseall -j /dev/mtd14
00000000 85 19 03 20 0c 00 00 00 b1 b0 1e e4 ff ff ff ff |... ............|
00000010 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
*
...
000a0000 85 19 03 20 0c 00 00 00 b1 b0 1e e4 ff ff ff ff |... ............|
000a0010 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
*
000c0000 85 19 03 20 0c 00 00 00 b1 b0 1e e4 ff ff ff ff |... ............|
000c0010 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
*
...
*
00860000 85 19 03 20 0c 00 00 00 b1 b0 1e e4 ff ff ff ff |... ............|
00860010 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
*
00880000
Image copy to mtd15 device and inspection, shows... (It could be seen that image was copy ok and CLEANMARKER size still is 0x0c)
dd if=firma_512.jffs2 of=/dev/mtd14
hexdump -C /dev/mtd14
(hexdump -C /dev/mtdblock14 gives the same result)
....
00081340 85 19 02 e0 44 10 00 00 6d 58 d1 84 02 00 00 00 |....D...mX......|
00081350 84 00 00 00 a4 81 00 00 e8 03 e8 03 00 00 08 00 |................|
00081360 a3 dc df 53 a3 dc df 53 a3 dc df 53 00 f0 07 00 |...S...S...S....|
00081370 00 10 00 00 00 10 00 00 00 00 00 00 db 7c 54 f0 |.............|T.|
00081380 3c 30 bd 6f aa 55 aa 55 aa 55 aa 55 aa 55 aa 55 |<0.o.U.U.U.U.U.U|
00081390 aa 55 aa 55 aa 55 aa 55 aa 55 aa 55 aa 55 aa 55 |.U.U.U.U.U.U.U.U|
*
00082380 aa 55 aa 55 ff ff ff ff ff ff ff ff ff ff ff ff |.U.U............|
00082390 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
*
000a0000 85 19 03 20 0c 00 00 00 b1 b0 1e e4 ff ff ff ff |... ............|
000a0010 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
*
000c0000 85 19 03 20 0c 00 00 00 b1 b0 1e e4 ff ff ff ff |... ............|
000c0010 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
And now the braindeath problem, at least for me.
mount -t jffs2 /dev/mtdblock14 /mnt/app2
dmesg
CLEANMARKER node found at 0x00000000 has totlen 0xc != normal 0x200
...
CLEANMARKER node found at 0x000c0000 has totlen 0xc != normal 0x200
CLEANMARKER node found at 0x000e0000 has totlen 0xc != normal 0x200
...
CLEANMARKER node found at 0x00860000 has totlen 0xc != normal 0x200
hexdump -C /dev/mtd14
....
00081340 85 19 02 e0 44 10 00 00 6d 58 d1 84 02 00 00 00 |....D...mX......|
00081350 84 00 00 00 a4 81 00 00 e8 03 e8 03 00 00 08 00 |................|
00081360 a3 dc df 53 a3 dc df 53 a3 dc df 53 00 f0 07 00 |...S...S...S....|
00081370 00 10 00 00 00 10 00 00 00 00 00 00 db 7c 54 f0 |.............|T.|
00081380 3c 30 bd 6f aa 55 aa 55 aa 55 aa 55 aa 55 aa 55 |<0.o.U.U.U.U.U.U|
00081390 aa 55 aa 55 aa 55 aa 55 aa 55 aa 55 aa 55 aa 55 |.U.U.U.U.U.U.U.U|
*
00082380 aa 55 aa 55 ff ff ff ff ff ff ff ff ff ff ff ff |.U.U............|
00082390 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
*
000a0000 85 19 03 20 00 02 00 00 67 db 4c ad ff ff ff ff |... ....g.L.....|
000a0010 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
*
000c0000 85 19 03 20 00 02 00 00 67 db 4c ad ff ff ff ff |... ....g.L.....|
000c0010 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
*
000e0000 85 19 03 20 00 02 00 00 67 db 4c ad ff ff ff ff |... ....g.L.....|
000e0010 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
The CLEANMARKER size change not only make a mess but waste a lot of space in device. Why at mount time it is changed? It can be avoided?
Your advise/suggestion are welcome
Target desrciption:
Linux-2.6.31
NOR: Spansion S29GL512S (Erase Sector 128kB Page Size 4kB x16dBUS)
I'm having trouble with my home made "for fun" nameserver. It's been a couple of months since I updated it so I'm a bit rusty and thought I'd ask here and see if someone else sees what's wrong. I'm getting a FORMERR when asking for a TXT record, and the same problem occur on different domains, so there's probably something wrong in the packet formatting. Anyone?
dig txt ffffff.com #ns1.ffffff.com
;; Got bad packet: FORMERR
1024 bytes
ce bf 84 00 00 01 00 01 00 02 00 00 06 66 66 66 .............fff
66 66 66 03 63 6f 6d 00 00 10 00 01 c0 0c 00 10 fff.com.........
00 01 00 00 02 58 00 13 12 57 65 6c 63 6f 6d 65 .....X...Welcome
20 74 6f 20 66 66 66 66 66 66 66 00 c0 0c 00 02 .to.fffffff.....
00 01 00 00 02 58 00 10 03 6e 73 31 06 66 66 66 .....X...ns1.fff
66 66 66 03 63 6f 6d 00 c0 0c 00 02 00 01 00 00 fff.com.........
02 58 00 10 03 6e 73 32 06 66 66 66 66 66 66 03 .X...ns2.ffffff.
63 6f 6d 00 00 00 00 00 00 00 00 00 00 00 00 00 com.............
In the example above supplied, I added an incorrect 00 (null terminator) at the end of the TXT-string. After removing the null terminator from the TXT records, the txt records now work on my nameserver.