/* This changes the definition of ucontext_t */ #define _XOPEN_SOURCE 1 #include #include #include #include #include #include #define offsetof(type, fld) ((unsigned long)&((type *)0)->fld) #define stringify(x) #x static int verbose = 0; #define _ASSERT_OP(a, op, b) \ do { \ unsigned long long _a = (unsigned long long)(a); \ unsigned long long _b = (unsigned long long)(b); \ if (verbose) \ fprintf(stderr, "%s:%d: ASSERT(" stringify(a) \ " " stringify(op) " " stringify(b) ")\n", \ __FILE__, __LINE__); \ if (!(_a op _b)) { \ fprintf(stderr, "%s:%d: FAILED ASSERT((" stringify(a) \ "=0x%016llx) " stringify(op) " (" stringify(b) "=0x%016llx))\n", \ __FILE__, __LINE__, _a, _b); \ _exit(1); \ } \ } while(0) #define ASSERT_EQ(a, b) _ASSERT_OP(a, ==, b) #define ASSERT_NE(a, b) _ASSERT_OP(a, !=, b) #define ASSERT_LTE(a, b) _ASSERT_OP(a, <=, b) #define ASSERT_GTE(a, b) _ASSERT_OP(a, >=, b) #define ASSERT(e) \ do { \ if (verbose) \ fprintf(stderr, "%s:%d: ASSERT(" stringify(e) ")\n", \ __FILE__, __LINE__); \ if (!(e)) { \ fprintf(stderr, "%s:%d: FAILED ASSERT(" stringify(e) ")\n", \ __FILE__, __LINE__); \ _exit(1); \ } \ } while(0) static bool using_int3 = false; static volatile int sig_count = 0; static volatile int ran_after_fault = 0; static void *top_of_stack; static void *bottom_of_stack; void this_function_halts(unsigned long long a0, unsigned long long a1, unsigned long long a2, unsigned long long a3, unsigned long long a4, unsigned long long a5) { int foo; bottom_of_stack = &foo; /* Set up registers with known values which will be tested in the signal handler */ __asm__ volatile("movq $0xfeed01010101cafe,%rax"); __asm__ volatile("movq $0xfeed02020202cafe,%rbx"); __asm__ volatile("movq $0xfeed03030303cafe,%r10"); __asm__ volatile("movq $0xfeed04040404cafe,%r11"); __asm__ volatile("movq $0xfeed05050505cafe,%r12"); __asm__ volatile("movq $0xfeed06060606cafe,%r13"); __asm__ volatile("movq $0xfeed07070707cafe,%r14"); __asm__ volatile("movq $0xfeed08080808cafe,%r15"); __asm__ volatile("hlt"); ran_after_fault++; } void this_function_int3s(unsigned long long a0, unsigned long long a1, unsigned long long a2, unsigned long long a3, unsigned long long a4, unsigned long long a5) { int foo; bottom_of_stack = &foo; /* Set up registers with known values which will be tested in the signal handler */ __asm__ volatile("movq $0xfeed01010101cafe,%rax"); __asm__ volatile("movq $0xfeed02020202cafe,%rbx"); __asm__ volatile("movq $0xfeed03030303cafe,%r10"); __asm__ volatile("movq $0xfeed04040404cafe,%r11"); __asm__ volatile("movq $0xfeed05050505cafe,%r12"); __asm__ volatile("movq $0xfeed06060606cafe,%r13"); __asm__ volatile("movq $0xfeed07070707cafe,%r14"); __asm__ volatile("movq $0xfeed08080808cafe,%r15"); __asm__ volatile("int $3"); ran_after_fault++; } static void handle_signal(int sig, siginfo_t *si, void *vuc) { ucontext_t *uc = (ucontext_t *)vuc; if (verbose) { fprintf(stderr, "handle_signal\n"); fflush(stderr); } sig_count++; ASSERT(sig_count == 1); int expected_sig = (using_int3 ? SIGTRAP : SIGSEGV); ASSERT_EQ(sig, expected_sig); ASSERT_NE(si, NULL); ASSERT_NE(uc, NULL); ASSERT_NE(uc->uc_mcontext, NULL); /* Test that the siginfo is set up right for this signal */ ASSERT_EQ(si->si_signo, expected_sig); ASSERT_EQ(si->si_errno, 0); int expected_code = (using_int3 ? 1 : 0); ASSERT_EQ(si->si_code, expected_code); ASSERT_EQ(si->si_pid, 0); ASSERT_EQ(si->si_uid, 0); ASSERT_EQ(si->si_status, 0); ASSERT_EQ(si->si_addr, 0); ASSERT_EQ(si->si_band, 0); /* Test that RAX is saved to the signal ucontext */ ASSERT_EQ(uc->uc_mcontext->__ss.__rax, 0xfeed01010101cafe); /* Test that the registers used to pass the 1st 6 * function arguments were saved in the signal ucontext */ ASSERT_EQ(uc->uc_mcontext->__ss.__rdi, 0xbabe01010101cedeULL); ASSERT_EQ(uc->uc_mcontext->__ss.__rsi, 0xbabe02020202cedeULL); ASSERT_EQ(uc->uc_mcontext->__ss.__rdx, 0xbabe03030303cedeULL); ASSERT_EQ(uc->uc_mcontext->__ss.__rcx, 0xbabe04040404cedeULL); ASSERT_EQ(uc->uc_mcontext->__ss.__r8, 0xbabe05050505cedeULL); ASSERT_EQ(uc->uc_mcontext->__ss.__r9, 0xbabe06060606cedeULL); /* Test that the saved RBP and RSP point into roughly the right * part of the stack */ ASSERT_GTE(uc->uc_mcontext->__ss.__rbp, bottom_of_stack); ASSERT_LTE(uc->uc_mcontext->__ss.__rbp, top_of_stack); ASSERT_GTE(uc->uc_mcontext->__ss.__rsp, bottom_of_stack); ASSERT_LTE(uc->uc_mcontext->__ss.__rsp, top_of_stack); /* Test that the saved RIP points into roughly the * right part of the text segment */ char *calling_fn = (using_int3 ? (char *)&this_function_int3s : (char *)&this_function_halts); ASSERT_GTE(uc->uc_mcontext->__ss.__rip, calling_fn); ASSERT_LTE(uc->uc_mcontext->__ss.__rip, calling_fn+400); ASSERT_EQ(uc->uc_mcontext->__ss.__rbx, 0xfeed02020202cafe); ASSERT_EQ(uc->uc_mcontext->__ss.__r10, 0xfeed03030303cafe); ASSERT_EQ(uc->uc_mcontext->__ss.__r11, 0xfeed04040404cafe); ASSERT_EQ(uc->uc_mcontext->__ss.__r12, 0xfeed05050505cafe); ASSERT_EQ(uc->uc_mcontext->__ss.__r13, 0xfeed06060606cafe); ASSERT_EQ(uc->uc_mcontext->__ss.__r14, 0xfeed07070707cafe); ASSERT_EQ(uc->uc_mcontext->__ss.__r15, 0xfeed08080808cafe); /* printf(" RFLAGS 0x%016llx\n", (unsigned long long)uc->uc_mcontext->__ss.__rflags); */ /* * Test that the RIP is restored from the signal ucontext; * this should skip past the HLT/INT instruction and * allow execution to continue back out to main() */ if (verbose) { fprintf(stderr, "Setting up to return past the HLT\n"); fflush(stderr); } uc->uc_mcontext->__ss.__rip += (using_int3 ? 0 : 1); if (verbose) { fprintf(stderr, "Returning from signal handler\n"); fflush(stderr); } } int main(int argc, char **argv) { int r; struct sigaction act; top_of_stack = (void *)&act; if (argc > 1 && !strcmp(argv[1], "--verbose")) verbose = 1; if (verbose) printf("Setting up signal handler\n"); memset(&act, 0, sizeof(act)); act.sa_sigaction = handle_signal; act.sa_flags |= SA_SIGINFO; if (RUNNING_ON_VALGRIND) using_int3 = true; r = sigaction((using_int3 ? SIGTRAP : SIGSEGV), &act, NULL); ASSERT_EQ(r, 0); if (verbose) { fprintf(stderr, "Calling function with a breakpoint insn in it\n"); fflush(stderr); } if (using_int3) this_function_int3s(0xbabe01010101cedeULL, 0xbabe02020202cedeULL, 0xbabe03030303cedeULL, 0xbabe04040404cedeULL, 0xbabe05050505cedeULL, 0xbabe06060606cedeULL); else this_function_halts(0xbabe01010101cedeULL, 0xbabe02020202cedeULL, 0xbabe03030303cedeULL, 0xbabe04040404cedeULL, 0xbabe05050505cedeULL, 0xbabe06060606cedeULL); ASSERT_EQ(ran_after_fault, 1); fprintf(stderr, "PASS\n"); return 0; }