I have a closed-source binary (minecraft-pi). For a given section of the assembly like so:
a2ed4: e92d45f8 push {r3, r4, r5, r6, r7, r8, sl, lr}
a2ed8: e1a04000 mov r4, r0
a2edc: e59d0024 ldr r0, [sp, #36] ; 0x24
a2ee0: e352007f cmp r2, #127 ; 0x7f
a2ee4: d3a02000 movle r2, #0
a2ee8: c3a02001 movgt r2, #1
a2eec: e1922fa0 orrs r2, r2, r0, lsr #31
a2ef0: 1a000015 bne a2f4c
conveniently there's another binary libminecraftpe.so that has code with symbols while containing similar disassembled instructions, and similar relative placement among functions e.g.:
0013a3ac <_ZN5Level11hasChunksAtEiiiiii>:
13a3ac: e92d 43f8 stmdb sp!, {r3, r4, r5, r6, r7, r8, r9, lr}
13a3b0: 2a7f cmp r2, #127 ; 0x7f
13a3b2: 4604 mov r4, r0
13a3b4: 9809 ldr r0, [sp, #36] ; 0x24
13a3b6: bfd4 ite le
13a3b8: 2200 movle r2, #0
13a3ba: 2201 movgt r2, #1
13a3bc: ea52 72d0 orrs.w r2, r2, r0, lsr #31
13a3c0: d119 bne.n 13a3f6 <_ZN5Level11hasChunksAtEiiiiii+0x4a>
(_ZN5Level11hasChunksAtEiiiiii ~ Level::hasChunksAt(int, int, int, int, int, int) according to c++filt).
This matches up because despite one being ARM + Linux and the other ARM/Thumb + Android, they come from roughly the same codebase.
It's thus appealing to build a symbol file for minecraft-pi by hand and use it in gdb. Even when primarily stepping through assembly it would be very helpful if I could set breakpoints on function names and see informative backtraces.
So if I have written up a map of addresses to symbol names, how can I generate a corresponding symbol file binary (to be loaded in gdb via the symbol-file command, or even embedded into the executable)?
I'm familiar with human-readable debug symbol formats like Breakpad syms, but are there tools for generating a DWARF binary in this manner?
I found other questions on Stack Exchange related to IDA integration, dwarfexport, pwndebug, and unstrip (included in links below). florisschabert/unstrip has ARM support but seems to be geared toward inserting symbols based on Objective-C standard libraries, which isn't applicable here. Using IDA with dwarfexport could be an option, but I'd prefer a command-line solution that I could script. I'm basically looking for advice on generally recommended practices before I try out these various tools with limited documentation.
Links:
