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27 lines
1.1 KiB
HTML
27 lines
1.1 KiB
HTML
<html><head><link rel="stylesheet" href="style.css"></head><body><div class="page">
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<h1>20140921 - Using GDB Without Source and With Runtime Changing of Code</h1>
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<br>
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Getting disassembly of code generated at runtime to verify dynamic code generation can be a slow process.
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On Linux, I just use gdb.
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Using gdb requires setting the breakpoint for run-time generated code
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after that code is generated by the application
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(if there is an easier way, I don't know it).
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Here is a quick example,<br>
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<br>
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<tt>
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Find the entry point of the ELF: readelf -a filename<br>
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Look for "Entry point address:" and write down address<br>
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Start gdb: gdb filename<br>
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Insert breakpoint, this example using 0x2c3 as entry point: break *0x2c3<br>
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Start program which will break at above entry point: run<br>
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Show disassembly with raw bytes example: disassemble /r 0x2c3,0x300<br>
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The "=>" shows the instruction pointer<br>
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Set another breakpoint to something after run-time generated code<br>
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Use the "continue" command to continue to that breakpoint<br>
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Show disassembly of the run-time generated code</tt><br>
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</div></body></html>
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