I need to write some gdb macros that need to different between 32 and 64 bit architectures. I'm looking for a way to determine in gdb whether the debugged executable is 32 or 64 bit.
info target includes info about file type
e.g. file type elf32-i386
but this is embedded in a longer output.
Being new to gdb macros, I don't know how to process that output, or find another way to get this.
Please, no python gdb for the time being.
Python API example
frame = gdb.selected_frame()
arch = frame.architecture()
print(arch.name())
Sample outputs:
i386 for a 32 bit ELFi386:x86-64 for a 64 bit ELFDocs: https://sourceware.org/gdb/onlinedocs/gdb/Architectures-In-Python.html
Tested on GDB 7.7.1, Ubuntu 14.04 AMD64.
Here is your solution, not 'contaminated' with python:
define set-program-arch
set logging file tmp.gdb
set logging overwrite on
set logging redirect on
set logging on
set pagination off
info target
set pagination on
set logging off
set logging redirect off
set logging overwrite off
shell echo -n 'set $program_arch="' > tmp2.gdb
shell grep 'file type' tmp.gdb | sed "s/\.$//g" | cut -d ' ' -f 4 | tr -d '\n' >> tmp2.gdb
shell echo '"' >> tmp2.gdb
source tmp2.gdb
shell rm -f tmp2.tmp tmp.gdb
end
This sets variable program_arch to ELF type of the binary being debugged (e.g. elf64-x86-64). Enjoy!
Actually, I found an extremely simple answer:
if sizeof(uintptr_t) == 4
set $arch = 32
else
set $arch = 64
end
unitptr_t a typo? Shouldn't that be uint not unit? Also, why do you use sizeof(uintptr_t) instead of sizeof(void *) or even sizeof(unsigned int *)? The latter might work better for C, C++, and Objective-C, not just C++11 and C99 with <stdint.h> included.Please, no python gdb for the time being.
I don't believe you can achieve what you want without python-gdb, and it is trivial to achieve what you want with it. So consider relaxing your restriction.