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I have a CS project that I need to diffuse a bomb (the Mr.Evil bomb if you have ever heard about it), but I am having problems with gdb when I want to set break points to lines. After I open the file in gdb and try to break a t a random line I get this problem: 

 gdb bomb 
 (gdb) break 15
 No symbol table is loaded.  Use the "file" command.

In addition, even when i use the "file" command I get 

 "/auto/bunter_usr/bomb": not in executable format: File format not recognized

I realized that the problem is because my professor has not used the -g flag when he has compiled the file. In the situation I am, is there a way to set breakpoints to lines?

FranXh
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2 Answers2

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"/auto/bunter_usr/bomb": not in executable format: File format not recognized
I realized that the problem is because my professor has not used the -g flag

Your realization is incorrect. An executable compiled without -g would not produce above message.

Most likely, the file you are pointing GDB at is a shell script, which invokes the real executable (perhaps after setting some environment variables, or adding some command line flags). You want to debug the real executable, not the shell script.

Employed Russian
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u need to desassemble the binary and check for memory location and set breakpoints for those locations.

here's how you gonna do it : gdb> b *0x80456789

here's a cheat sheet for reference http://csapp.cs.cmu.edu/public/docs/gdbnotes-ia32.pdf

Himz
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