memcheck/tests/amd64-solaris/context_rflags.c

   1 /* Test if rflags values are correctly propagated in and out of a signal
   2    handler.  Note that we actually test only the propagation of the overflow
   3    and sign flags. */
   4
   5 #include <assert.h>
   6 #include <signal.h>
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <unistd.h>
  10 #include <sys/regset.h>
  11 #include <sys/syscall.h>
  12 #include <ucontext.h>
  13
  14 #define OBIT(rflags) (!!((rflags) & (1 << 11)))
  15 #define SBIT(rflags) (!!((rflags) & (1 << 7)))
  16
  17 static siginfo_t si;
  18 static ucontext_t uc;
  19
  20 static void sighandler(int sig, siginfo_t *sip, void *arg)
  21 {
  22    si = *sip;
  23    uc = *((ucontext_t *) arg);
  24 }
  25
  26 int main(void)
  27 {
  28    struct sigaction sa;
  29    pid_t pid;
  30    long rflags;
  31
  32    sa.sa_sigaction = sighandler;
  33    sa.sa_flags = SA_SIGINFO;
  34    if (sigfillset(&sa.sa_mask)) {
  35       perror("sigfillset");
  36       return 1;
  37    }
  38    if (sigaction(SIGUSR1, &sa, NULL)) {
  39       perror("sigaction");
  40       return 1;
  41    }
  42
  43    pid = getpid();
  44
  45    __asm__ __volatile__(
  46       /* Set overflow and sign flags. */
  47       "movl   $1, %%edx\n"
  48       "addl   $0x7fffffff, %%edx\n"
  49
  50       /* Trigger the signal handler. */
  51       "syscall\n"
  52       "pushfq\n"
  53       "popq   %%rdx\n"
  54       : "=d" (rflags)
  55       : "a" (SYS_kill), "D" (pid), "S" (SIGUSR1)
  56       : "cc", "memory");
  57
  58    printf("Values in the signal handler:\n");
  59    printf("  overflow=%d, sign=%d\n",
  60           OBIT(uc.uc_mcontext.gregs[REG_RFL]),
  61           SBIT(uc.uc_mcontext.gregs[REG_RFL]));
  62
  63    printf("Values after the return from the signal handler:\n");
  64    printf("  overflow=%d, sign=%d\n", OBIT(rflags), SBIT(rflags));
  65
  66    return 0;
  67 }
  68