mirror of
https://github.com/ioacademy-jikim/debugging
synced 2025-06-08 08:26:14 +00:00
68 lines
1.5 KiB
C
68 lines
1.5 KiB
C
/* Test if rflags values are correctly propagated in and out of a signal
|
|
handler. Note that we actually test only the propagation of the overflow
|
|
and sign flags. */
|
|
|
|
#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(rflags) (!!((rflags) & (1 << 11)))
|
|
#define SBIT(rflags) (!!((rflags) & (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;
|
|
long rflags;
|
|
|
|
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"
|
|
|
|
/* Trigger the signal handler. */
|
|
"syscall\n"
|
|
"pushfq\n"
|
|
"popq %%rdx\n"
|
|
: "=d" (rflags)
|
|
: "a" (SYS_kill), "D" (pid), "S" (SIGUSR1)
|
|
: "cc", "memory");
|
|
|
|
printf("Values in the signal handler:\n");
|
|
printf(" overflow=%d, sign=%d\n",
|
|
OBIT(uc.uc_mcontext.gregs[REG_RFL]),
|
|
SBIT(uc.uc_mcontext.gregs[REG_RFL]));
|
|
|
|
printf("Values after the return from the signal handler:\n");
|
|
printf(" overflow=%d, sign=%d\n", OBIT(rflags), SBIT(rflags));
|
|
|
|
return 0;
|
|
}
|
|
|