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#define _GNU_SOURCE
#include <stdio.h>
#include <signal.h>
#include <unistd.h>
#include <sys/ucontext.h>
#include <asm/unistd.h>
#define VAL1 0x11223344
#define VAL2 0x44332211
static void handler1(int sig, siginfo_t *si, ucontext_t *uc)
{
/* Since the handler will be called as kill leaves the kernel,
this is replacing the kill syscall's return value. */
if (uc->uc_mcontext.gregs[REG_EAX] != 0)
printf("FAILED: handler2 expected eax == 0, not %d\n", uc->uc_mcontext.gregs[REG_EAX]);
uc->uc_mcontext.gregs[REG_EAX] = VAL1;
asm volatile (
"movl $0, %%edx\n"
"movl $0, %%esi\n"
"movl $0, %%edi\n"
: : : "edx", "esi", "edi");
}
static void handler2(int sig, struct sigcontext sc)
{
/* Since the handler will be called as kill leaves the kernel,
this is replacing the kill syscall's return value. */
if (sc.eax != 0)
printf("FAILED: handler2 expected eax == 0, not %p\n", (void*)sc.eax);
sc.eax = VAL2;
asm volatile (
"movl $0, %%edx\n"
"movl $0, %%esi\n"
"movl $0, %%edi\n"
: : : "edx", "esi", "edi");
}
int main()
{
struct sigaction sa;
int ret;
int v2, v3, v4;
sa.sa_handler = (void*)handler1;
sa.sa_flags = SA_SIGINFO;
sigfillset(&sa.sa_mask);
sigaction(SIGUSR1, &sa, NULL);
sa.sa_handler = (void*)handler2;
sa.sa_flags = 0;
sigfillset(&sa.sa_mask);
sigaction(SIGUSR2, &sa, NULL);
asm volatile (
//"movl $0x11111111, %%ebp\n"
"movl $0x22222222, %%edx\n"
"movl $0x33333333, %%esi\n"
"movl $0x44444444, %%edi\n"
"int $0x80"
: "=a" (ret), "=d" (v2), "=S" (v3), "=D" (v4)
: "0" (__NR_kill), "b" (getpid()), "c" (SIGUSR1));
printf("v2=%x v3=%x v4=%x\n", v2, v3, v4);
if (ret == VAL1)
printf("PASS %x\n", ret);
else
printf("FAIL ret=%x not %x\n", ret, VAL1);
asm volatile (
//"movl $0x11111111, %%ebp\n"
"movl $0x22222222, %%edx\n"
"movl $0x33333333, %%esi\n"
"movl $0x44444444, %%edi\n"
"int $0x80"
: "=a" (ret), "=d" (v2), "=S" (v3), "=D" (v4)
: "0" (__NR_kill), "b" (getpid()), "c" (SIGUSR2));
printf("v2=%x v3=%x v4=%x\n", v2, v3, v4);
if (ret == VAL2)
printf("PASS %x\n", ret);
else
printf("FAIL ret=%x not %x\n", ret, VAL2);
return 0;
}
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