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#undef _GNU_SOURCE
#define _GNU_SOURCE 1
#include <signal.h>
#include <stdio.h>
#include <sys/ucontext.h>
static char* rip_at_sig = NULL;
static void int_handler(int signum, siginfo_t *si, void *uc_arg)
{
ucontext_t *uc = (ucontext_t *)uc_arg;
/* Note that uc->uc_mcontext is an embedded struct, not a pointer */
mcontext_t *mc = &(uc->uc_mcontext);
void *pc = (void*)mc->gregs[REG_RIP];
printf("in int_handler, RIP is ...\n");
rip_at_sig = pc;
}
static void register_handler(int sig, void *handler)
{
struct sigaction sa;
sa.sa_flags = SA_RESTART | SA_SIGINFO;
sigfillset(&sa.sa_mask);
sa.sa_sigaction = handler;
sigaction(sig, &sa, NULL);
}
int main(void) {
char *intaddr = NULL;
puts("main");
register_handler(SIGTRAP, int_handler);
asm volatile(
"movabsq $zz_int, %%rdx\n"
"mov %%rdx, %0\n"
"zz_int:\n"
"int $3\n"
: /* no outputs */
: "m" (intaddr) /* input: address of var to store target addr to */
: /* clobbers */ "rdx"
);
/* intaddr is the address of the int 3 insn. rip_at_sig is the PC
after the exception, which should be the next insn along.
Hence: */
if (intaddr != NULL && rip_at_sig != NULL
&& rip_at_sig == intaddr+1)
printf("PASS\n");
else
printf("FAIL\n");
return 0;
}
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