/* x86 variant of the amd64-solaris/context_rflags.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;
static void sighandler(int sig, siginfo_t *sip, ucontext_t *ucp)
{
si = *sip;
uc = *ucp;
}
int main(void)
{
struct sigaction sa;
pid_t pid;
int eflags;
sa.sa_handler = sighandler;
sa.sa_flags = SA_SIGINFO;
if (sigfillset(&sa.sa_mask)) {
perror("sigfillset");
return 1;
}
if (sigaction(SIGUSR1, &sa, NULL)) {
perror("sigaction");
return 1;
}
pid = getpid();
__asm__ __volatile__(
/* Set overflow and sign flags. */
"movl $1, %%edx\n"
"addl $0x7fffffff, %%edx\n"
/* Prepare syscall parameters. */
"pushl %[sig]\n"
"pushl %[pid]\n"
"pushl $0xdeadbeef\n"
"movl %[scall], %%eax\n"
/* Trigger the signal handler. */
"int $0x91\n"
"pushfl\n"
"popl %%edx\n"
"addl $12, %%esp\n"
: "=d" (eflags)
: [scall] "i" (SYS_kill), [pid] "a" (pid), [sig] "i" (SIGUSR1)
: "cc", "memory");
printf("Values in the signal handler:\n");
printf(" overflow=%d, sign=%d\n",
OBIT(uc.uc_mcontext.gregs[EFL]), SBIT(uc.uc_mcontext.gregs[EFL]));
printf("Values after the return from the signal handler:\n");
printf(" overflow=%d, sign=%d\n", OBIT(eflags), SBIT(eflags));
return 0;
}