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Topic created on: December 30, 2008 10:17 CST by zzo .

I am writing a customised ELF file loader for IDA Pro.

Can someone please explain how to do relocation fixups correctly with functions listed in fixup.hpp? It's not really any clear about that from docs/samples. :( A well commented example will do too.

nezumi		January 1, 2009 14:38.04 CST
use set_fixup (ea_t source, fixup_data_t *fp), where ea_t - the address of the cell that has to be changed, fp - type of the relocation and target offset/displacement (see the fixup_data_t definition in fixup.hpp); there is a good example in SDK, open \ldr\dos\dos.cpp and see doRelocs() function. it applies relocations, calling set_fixup() for every fixup element. IDA kernel memorizes this and patchs the loaded file by itself.

zzo		January 2, 2009 06:06.58 CST
as for that example, doRelocs() function does patch the loaded data itself by using put_word() call (line 166). also, it shows only segment fixups, and i'm having troubles with MIPS's HI16/LO16 fixups. :( can you please elaborate on fields of fixup_data_t structure? it's a bit unclear about "offset" and "displacement" fields -- when we should use the first and when the second, and how the fixup is applied in both cases. thanks!!

abuse007		January 21, 2009 23:25.01 CST
What do you mean by MIPS Hi16/Lo16 Fixups?

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