/* x86 variant of the amd64-solaris/context_rflags2.c test. */
#include <assert.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/ucontext.h>
#define OBIT(eflags) (!!((eflags) & (1 << 11)))
#define SBIT(eflags) (!!((eflags) & (1 << 7)))
static siginfo_t si;
static ucontext_t uc;
void break_out(void);
static void sighandler(int sig, siginfo_t *sip, ucontext_t *ucp)
{
si = *sip;
uc = *ucp;
/* Break out of the endless loop. */
*(uintptr_t*)&ucp->uc_mcontext.gregs[EIP] = (uintptr_t)break_out;
}
int main(void)
{
struct sigaction sa;
int eflags;
int x1;
/* Uninitialised, but we know px[0] is 0x0. */
int *px = malloc(sizeof(*px));
x1 = px[0] + 1;
sa.sa_handler = sighandler;
sa.sa_flags = SA_SIGINFO;
if (sigfillset(&sa.sa_mask)) {
perror("sigfillset");
return 1;
}
if (sigaction(SIGALRM, &sa, NULL)) {
perror("sigaction");
return 1;
}
alarm(2);
__asm__ __volatile__(
/* Set overflow and sign flags. */
"movl %[x1], %%edx\n"
"addl $0x7fffffff, %%edx\n"
/* Loopity loop, this is where the SIGALRM is triggered. */
"1:\n"
"jmp 1b\n"
"break_out:\n"
"pushfl\n"
"popl %%edx\n"
: "=d" (eflags)
: [x1] "m" (x1)
: "cc", "memory");
/* Check that the overflow and sign flags are uninitialised.
Note: This actually fails because the eflags are only approximate
(always initialised) in the signal handler. */
if (!OBIT(uc.uc_mcontext.gregs[EFL]) || !SBIT(uc.uc_mcontext.gregs[EFL]))
assert(0);
/* Check that the overflow and sign flags are uninitialised. */
if (!OBIT(eflags) || !SBIT(eflags))
assert(0);
return 0;
}