comandos da aula de so2

gcc -E hello.c -o hello.i
gcc -S hello.i -o hello.s
gcc -c hello.i -o hello.o

  ``.rodata`` => read-only data
objdump -h hello.o => headers
objdump -t hello.o => tabela de simbolos
objdump -r hello.o => entradas de relocacao
objdump -D hello.o => assemblt de todas as sessoes
objdump -s hello.o => dados
objdump -s -j .rodata hello.o => dados apenas do sessao .rodata

ld -o hello hello.o -lc => linka o programa, usando libc

ld -static -o hello -L `gcc -print-file-name=` /usr/lib/crt1.o /usr/lib/crti.o hello.o /usr/lib/crtn.o -lc -lgcc
find /usr/lib -name crt1.o
ld -static -o hello -L `gcc -print-file-name=` /usr/lib/x86_64-linux-gnu/crt1.o /usr/lib/x86_64-linux-gnu/crti.o hello.o /usr/lib/x86_64-linux-gnu/crtn.o -lc -lgcc
ld -static -o hello -L `gcc -print-file-name=` /usr/lib/x86_64-linux-gnu/crt1.o /usr/lib/x86_64-linux-gnu/crti.o hello.o /usr/lib/x86_64-linux-gnu/crtn.o --start-group -lc -lgcc -lgcc_eh --end-group

./hello
objdump -hrt hello

strip hello
objdump -hrt hello

readelf -h hello

gdb hello
p main
p _start
x/x 0x400830
disassemble _start

b _start
info registers
rip => instruction pointer
cs => code segment
ss => stack segment
...
disasseble main
b main => breakpoint no main
b *0x01230123 => breakpoint no endereco
stepi => step instruction

hello.c

#include <stdio.h>

int main(){
  printf("Hello world!\n");

  return 0;
}