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#include <elf.h>
int ifunc(void);
/* We have to write our own libc-like initialization code,
* and also invoke it ourselves before we do anything else. */
extern Elf64_Rela __rela_iplt_start;
extern Elf64_Rela __rela_iplt_end;
static void init(void)
{
Elf64_Rela *p_r;
for (p_r = &__rela_iplt_start; p_r != &__rela_iplt_end; ++p_r)
{
if (ELF64_R_TYPE(p_r->r_info) == R_X86_64_IRELATIVE)
{
void **site = (void**) p_r->r_offset;
void *(*resolver)(void) = (void*) p_r->r_addend;
*site = resolver();
}
}
}
int _start(void) __attribute__((noreturn));
int _start(void)
{
__asm__ volatile ("callq init\n\
callq ifunc\n\
movq %%rax, %%rdi \n\
movq $60, %%rax # exit \n\
syscall"
: : : "%rax", "%rdi" );
__builtin_unreachable();
}
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