| /* 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; |
| } |
| |