1 #define _GNU_SOURCE 2 3 #include <stdio.h> 4 #include <signal.h> 5 #include <unistd.h> 6 #include <sys/ucontext.h> 7 #include <asm/unistd.h> 8 9 #define VAL1 0x11223344 10 #define VAL2 0x44332211 11 12 static void handler1(int sig, siginfo_t *si, ucontext_t *uc) 13 { 14 /* Since the handler will be called as kill leaves the kernel, 15 this is replacing the kill syscall's return value. */ 16 if (uc->uc_mcontext.gregs[REG_EAX] != 0) 17 printf("FAILED: handler2 expected eax == 0, not %d\n", uc->uc_mcontext.gregs[REG_EAX]); 18 uc->uc_mcontext.gregs[REG_EAX] = VAL1; 19 20 asm volatile ( 21 "movl $0, %%edx\n" 22 "movl $0, %%esi\n" 23 "movl $0, %%edi\n" 24 : : : "edx", "esi", "edi"); 25 } 26 27 static void handler2(int sig, struct sigcontext sc) 28 { 29 /* Since the handler will be called as kill leaves the kernel, 30 this is replacing the kill syscall's return value. */ 31 if (sc.eax != 0) 32 printf("FAILED: handler2 expected eax == 0, not %p\n", (void*)sc.eax); 33 34 sc.eax = VAL2; 35 36 asm volatile ( 37 "movl $0, %%edx\n" 38 "movl $0, %%esi\n" 39 "movl $0, %%edi\n" 40 : : : "edx", "esi", "edi"); 41 } 42 43 int main() 44 { 45 struct sigaction sa; 46 int ret; 47 int v2, v3, v4; 48 49 sa.sa_handler = (void*)handler1; 50 sa.sa_flags = SA_SIGINFO; 51 sigfillset(&sa.sa_mask); 52 53 sigaction(SIGUSR1, &sa, NULL); 54 55 sa.sa_handler = (void*)handler2; 56 sa.sa_flags = 0; 57 sigfillset(&sa.sa_mask); 58 59 sigaction(SIGUSR2, &sa, NULL); 60 61 asm volatile ( 62 //"movl $0x11111111, %%ebp\n" 63 "movl $0x22222222, %%edx\n" 64 "movl $0x33333333, %%esi\n" 65 "movl $0x44444444, %%edi\n" 66 "int $0x80" 67 : "=a" (ret), "=d" (v2), "=S" (v3), "=D" (v4) 68 : "0" (__NR_kill), "b" (getpid()), "c" (SIGUSR1)); 69 printf("v2=%x v3=%x v4=%x\n", v2, v3, v4); 70 71 if (ret == VAL1) 72 printf("PASS %x\n", ret); 73 else 74 printf("FAIL ret=%x not %x\n", ret, VAL1); 75 76 asm volatile ( 77 //"movl $0x11111111, %%ebp\n" 78 "movl $0x22222222, %%edx\n" 79 "movl $0x33333333, %%esi\n" 80 "movl $0x44444444, %%edi\n" 81 "int $0x80" 82 : "=a" (ret), "=d" (v2), "=S" (v3), "=D" (v4) 83 : "0" (__NR_kill), "b" (getpid()), "c" (SIGUSR2)); 84 printf("v2=%x v3=%x v4=%x\n", v2, v3, v4); 85 86 if (ret == VAL2) 87 printf("PASS %x\n", ret); 88 else 89 printf("FAIL ret=%x not %x\n", ret, VAL2); 90 91 return 0; 92 } 93
