C / C++ / MFC

26-Nov-12 20:52

Hi,
I shred a file with the implementation of Peter Gutmann's algorithm in C++
but I can't shred a folder yet.
please instuct. Thumbs Up | :thumbsup:

David Crow27-Nov-12 3:57

David Crow

27-Nov-12 3:57

MehdiHazrati wrote:
but I can't shred a folder yet.

Why not? Is the code giving an error?

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MehdiHazrati27-Nov-12 4:26

27-Nov-12 4:26

The code is resposing well, but it is usefull for file shreding, it uses WriteFile() to overwrite on the file.
For shredding a folder I must search the space of the folder & iterate this procedure for all files, and about the subfolder we need a recursive code to traverse them.
Is there any better solution to wipe a folder of shred a whole drive?

Thanks.

Richard MacCutchan27-Nov-12 4:28

27-Nov-12 4:28

You cannot 'shred' folders in this way, as they are not writable in the same way that files are.

One of these days I'm going to think of a really clever signature.

MehdiHazrati27-Nov-12 4:50

27-Nov-12 4:50

I thinked that the files of the folder could be deleted in this way and finally the empty folder that is not important can be deleted from the system instructions.
This idea is feasible, but the only concern is about the complexity for the huge folders with various subfolders; it is time consuming.

Richard MacCutchan27-Nov-12 5:05

27-Nov-12 5:05

MehdiHazrati wrote:
it is time consuming.

That's why we write programs.

One of these days I'm going to think of a really clever signature.

MehdiHazrati27-Nov-12 5:23

27-Nov-12 5:23

Is there alternative solution to do this?
Specially for wiping a drive

David Crow27-Nov-12 6:04

David Crow

27-Nov-12 6:04

MehdiHazrati wrote:
Specially for wiping a drive

Format it, perhaps?

Richard MacCutchan27-Nov-12 6:29

27-Nov-12 6:29

You can access a volume or physical disk through the CreateFile()[^] function. This would allow you to overwrite all information including the file system tables.

One of these days I'm going to think of a really clever signature.

David Crow27-Nov-12 6:03

David Crow

27-Nov-12 6:03

MehdiHazrati wrote:
This idea is feasible, but the only concern is about the complexity for the huge folders with various subfolders; it is time consuming.

Have you considered SHFileOperation() or IFileOperation()? They can recursively delete subfolders.

jschell27-Nov-12 13:08

jschell

27-Nov-12 13:08

From the other responses presumably the following is what you want to do.
1. You want to shred files.
2. You want to shred file information in the directory itself.

For 1 you iterate over files in the directory and recurse through each sub directory and shred each file. You MUST do this. There is no magic solution that would allow you to do it in some other way.

For 2 it is more complex and depends on what you want you think a 'shred' would do. At a minor level you can just rename each file before shredding it. That overwrites the name. For a real shred you would need to
1. Create an API to access the file system at a raw level
2. Parse the file block
3. Shred the relevant file info that was found by step 1. In this case 'shred' includes the same basic methodology employed to shred a file but on a very small scale. You would need to write the shred code yourself.

Note that if you choose to implement the solution above then you MUST back up your hard drive because when you mess up the code you will need to reformat the hard drive. You must also extensively test this feature as well for the same reason. Also account for different file system types (like ssd and usb.)

MehdiHazrati27-Nov-12 17:45

27-Nov-12 17:45

thank you for your instructions
but I want to know if there is any way to rewrite the folder area outright and do not delete its files one by one

Regards.

jschell28-Nov-12 8:33

jschell

28-Nov-12 8:33

MehdiHazrati wrote:
but I want to know if there is any way to rewrite the folder area outright and
do not delete its files one by one

No.

File systems do not work like that.

do-while did not work

ho_khalaf26-Nov-12 19:36

26-Nov-12 19:36

XML

#include <stdio.h>
#include <stdlib.h>

int main(void) {
    char again;
    do{
        printf("insert y or Y to repeat");
        fflush(stdout);
        scanf("%c",&again);
    }while(again=='y'||again=='Y');
}

i wrote this code to create a loop that when insert y or Y do the job again but did not work.when i enter first y the loop be end.

Andy41126-Nov-12 19:55

Andy411

26-Nov-12 19:55

As mentioned in the QA section: Please don't cross post. I decided to answer you here.

Did you take a look at "again" in the debugger? You will recognize that in the second round thru the loop it will have the value 0x0a == \r it's the carriage return from your input.

You can try something like this to catch the CR:

C++

char cr;
char again;
do
{
    printf("insert y or Y to repeat");
    fflush(stdout);

    again = getchar();
    cr = getchar();

}while(again=='y'||again=='Y');

ho_khalaf26-Nov-12 20:04

26-Nov-12 20:04

thank you very much Andy411.its work good.
what do you use

cr = getchar();

what do this code

Andy41126-Nov-12 20:08

Andy411

26-Nov-12 20:08

How do you learn C? Don't you have a book or a tutoroial with an index? Confused | :confused:

That's what google answered me:
http://www.cplusplus.com/reference/cstdio/getchar/[^]

PS: Sorry if my answer sounds a bit rude, but I am realy confused about the question what getchar does. If I were you, my first step would be asking google, bing are whatever searchmachine you want. Or taking a look inside a book. If I don't understand the description/answer there, I would ask in a forum again.

water-moon201226-Nov-12 20:20

water-moon2012

26-Nov-12 20:20

run your code ,you will get the result.
"insert y or Y to repeatY insert y or Y to repeat"
then code end.

it is useless.

C++

fflush(stdout);

you can write

C++

fflush(stdin);

eclipse

ho_khalaf26-Nov-12 8:02

26-Nov-12 8:02

is there any body work with eclipse c\c++ ide ?
I write this code in eclipse C\C++ IDE but did not work.
its work in codeblocks bud didnt work in eclipse c++ ide.

C++

XML

#include <stdio.h>
#include <stdlib.h>

int main(void) {
    int a=100;
    do{
        printf("insert a");
        scanf("%d",&a);
    }while(a<10);
    return (0);
}

Re: eclipse

Maximilien26-Nov-12 8:04

Maximilien

26-Nov-12 8:04

what is not working ? compile error ? execution error ?

Nihil obstat

Re: eclipse

ho_khalaf26-Nov-12 8:08

26-Nov-12 8:08

it compile but the console tab did not show any thing.and when i push the stop button and stop the project just show "insert a" and stop.

Re: eclipse

Richard MacCutchan26-Nov-12 8:15