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Cocoo
#1 Jun 9 2018 08:50pm
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Looking to start finding memory addresses with specific spots in memory and learning how to do things like changing the value in that spot.
Any idea on where to get started?

So far I've opened up specific files that would go into a car and was able to read values and stuff but now I want to write/find/change.
Any suggestions would help :)
Cocoo
#2 Jun 10 2018 10:36am
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Was told to specify a little. I need to to see if I can get more throughput by checking if the values in memory are garbage or not. If I can pinpoint which values are being passed through memory as garbage and focus primarily on data, I could use a pointer to get the core data opposed to having the trash passed through speeding up the process.
tussilago
#3 Jun 10 2018 03:12pm
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Generally, heap analysis should be done with tools that make this sort of work much much easier.

Quote (Cocoo @ Jun 10 2018 05:36pm)
by checking if the values in memory are garbage or not.


Are you concerned with memory leaks or what do you mean by garbage? I'd be happy to elaborate more on this topic with you if you explain a bit more about your question :)

Cocoo
#4 Jun 10 2018 07:48pm
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Quote (tussilago @ Jun 10 2018 02:12pm)
Generally, heap analysis should be done with tools that make this sort of work much much easier.



Are you concerned with memory leaks or what do you mean by garbage? I'd be happy to elaborate more on this topic with you if you explain a bit more about your question :)


So there's a pre-buffer time that starts and once a value is hit it starts recording. The pre-buffer values are still in memory and aren't essentially cleared. I want to just point to the necessary data if that makes sense?
tussilago
#5 Jun 13 2018 07:11am
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Hmm, I still don't quite understand your question entirely. Have you posted it on stackoverflow?

By the way, what language are you working with?
Cocoo
#6 Jun 13 2018 03:33pm
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Quote (tussilago @ Jun 13 2018 06:11am)
Hmm, I still don't quite understand your question entirely. Have you posted it on stackoverflow?

By the way, what language are you working with?


C#, basically my question is I don't know how to use little/big endian (address) to get the value (hexadecimal) out of the location. I have no idea where to start. We have a prebuffer time which sends garbage data through first and after a select time the actual data we need is passed through and that's all we care about. I want to just focus on that and push all the garbage values out but to do that I need to know how to find the address (little/big Endian) and confirm the data values are accurate (hexadecimal).
waraholic
#7 Jun 13 2018 05:23pm
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Quote (Cocoo @ Jun 13 2018 04:33pm)
C#, basically my question is I don't know how to use little/big endian (address) to get the value (hexadecimal) out of the location. I have no idea where to start. We have a prebuffer time which sends garbage data through first and after a select time the actual data we need is passed through and that's all we care about. I want to just focus on that and push all the garbage values out but to do that I need to know how to find the address (little/big Endian) and confirm the data values are accurate (hexadecimal).


You shouldn't be doing anything like this in c#. You're not explaining your homework very well. You could just post the whole thing here and someone may help you.

If the problem is that you need to read a memory address from hex you can see this answer: https://stackoverflow.com/questions/30476131/c-sharp-read-pointer-address-value
If the problem is that you don't know what little and big endian are you can use this: https://searchnetworking.techtarget.com/definition/big-endian-and-little-endian
If the problem is something else you can use this: https://www.google.com
Cocoo
#8 Jun 13 2018 08:25pm
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Quote (waraholic @ Jun 13 2018 04:23pm)
You shouldn't be doing anything like this in c#. You're not explaining your homework very well. You could just post the whole thing here and someone may help you.

If the problem is that you need to read a memory address from hex you can see this answer: https://stackoverflow.com/questions/30476131/c-sharp-read-pointer-address-value
If the problem is that you don't know what little and big endian are you can use this: https://searchnetworking.techtarget.com/definition/big-endian-and-little-endian
If the problem is something else you can use this: https://www.google.com/


It's not homework, and okay I guess this will help clarify. Cars use different testing tools to read data such as emission controls and sensors. The little/big endian passes in the data which is generally garbage values first, and we have to translate it from hexadecimal. The issue is the memory address and finding the exact spot as well as the specific values. It's not really homework... the first link is more helpful but not what I'm looking for because I don't know the address or how to get it... Let's start there?
waraholic
#9 Jun 14 2018 03:42pm
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Quote (Cocoo @ Jun 13 2018 09:25pm)
It's not homework, and okay I guess this will help clarify. Cars use different testing tools to read data such as emission controls and sensors. The little/big endian passes in the data which is generally garbage values first, and we have to translate it from hexadecimal. The issue is the memory address and finding the exact spot as well as the specific values. It's not really homework... the first link is more helpful but not what I'm looking for because I don't know the address or how to get it... Let's start there?


Is this a hard coded memory address? If so I would imagine it is documented somewhere. If not you're going to have to analyze all of the pointers which is going to be annoying grunt work and should be done with a tool like tussilago said.

Sorry, I'm really still not understanding the question you're asking.

Quote
The little/big endian passes in the data which is generally garbage values first, and we have to translate it from hexadecimal.

So you're given a memory address and the data in it is changing? Is that correct? What does this data represent?

Quote
The issue is the memory address and finding the exact spot as well as the specific values.

What is the issue? You don't know the memory address? You don't know what it is pointing at?
Cocoo
#10 Jun 14 2018 04:33pm
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Quote (waraholic @ Jun 14 2018 02:42pm)
Is this a hard coded memory address? If so I would imagine it is documented somewhere. If not you're going to have to analyze all of the pointers which is going to be annoying grunt work and should be done with a tool like tussilago said.

Sorry, I'm really still not understanding the question you're asking.


So you're given a memory address and the data in it is changing? Is that correct? What does this data represent?


What is the issue? You don't know the memory address? You don't know what it is pointing at?


Bing bing bing finally we're getting somewhere, it's not a hardcoded address, I have to find the address :P so yes analyzing is what I have to that you for suggesting that tool :D
Indeed, the data is changing because new data is passed through, the data represents garbage pre-recording data that is un-necessary until about a few minutes in which is what I need to get out. I need to say for example if ( value >= 1010 (the hex value) )
return 10;

But then I need it to continue it'll be taking fragments of the endian.

Hope this clarifies but as we talk this is getting easier :D appreciate it!
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