1 /* x86 variant of the amd64-solaris/context_rflags.c test. */
2 
3 #include <assert.h>
4 #include <signal.h>
5 #include <stdio.h>
6 #include <stdlib.h>
7 #include <unistd.h>
8 #include <sys/regset.h>
9 #include <sys/syscall.h>
10 #include <sys/ucontext.h>
11 
12 #define OBIT(eflags) (!!((eflags) & (1 << 11)))
13 #define SBIT(eflags) (!!((eflags) & (1 << 7)))
14 
15 static siginfo_t si;
16 static ucontext_t uc;
17 
18 static void sighandler(int sig, siginfo_t *sip, void *arg)
19 {
20    si = *sip;
21    uc = *((ucontext_t *) arg);
22 }
23 
24 int main(void)
25 {
26    struct sigaction sa;
27    pid_t pid;
28    int eflags;
29 
30    sa.sa_sigaction = sighandler;
31    sa.sa_flags = SA_SIGINFO;
32    if (sigfillset(&sa.sa_mask)) {
33       perror("sigfillset");
34       return 1;
35    }
36    if (sigaction(SIGUSR1, &sa, NULL)) {
37       perror("sigaction");
38       return 1;
39    }
40 
41    pid = getpid();
42 
43    __asm__ __volatile__(
44       /* Set overflow and sign flags. */
45       "movl   $1, %%edx\n"
46       "addl   $0x7fffffff, %%edx\n"
47 
48       /* Prepare syscall parameters. */
49       "pushl  %[sig]\n"
50       "pushl  %[pid]\n"
51       "pushl  $0xdeadbeef\n"
52       "movl   %[scall], %%eax\n"
53 
54       /* Trigger the signal handler. */
55       "int    $0x91\n"
56       "pushfl\n"
57       "popl   %%edx\n"
58       "addl   $12, %%esp\n"
59       : "=d" (eflags)
60       : [scall] "i" (SYS_kill), [pid] "a" (pid), [sig] "i" (SIGUSR1)
61       : "cc", "memory");
62 
63    printf("Values in the signal handler:\n");
64    printf("  overflow=%d, sign=%d\n",
65           OBIT(uc.uc_mcontext.gregs[EFL]), SBIT(uc.uc_mcontext.gregs[EFL]));
66 
67    printf("Values after the return from the signal handler:\n");
68    printf("  overflow=%d, sign=%d\n", OBIT(eflags), SBIT(eflags));
69 
70    return 0;
71 }
72 
73