| /* This changes the definition of ucontext_t */ |
| #define _XOPEN_SOURCE 1 |
| #include <stdio.h> |
| #include <unistd.h> |
| #include <signal.h> |
| #include <string.h> |
| #include <stdbool.h> |
| #include <valgrind.h> |
| |
| #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(void) |
| { |
| int foo; |
| bottom_of_stack = &foo - 4; |
| /* EAX is used by compiler-generated code to |
| * increment ran_after_fault, so we need to |
| * preserve it in our asm section */ |
| unsigned long saved_eax; |
| |
| /* Set up registers with known values which will be tested in the signal handler */ |
| __asm__ volatile("movl %%eax, %0" : "=m"(saved_eax)); |
| __asm__ volatile("movl $0xfeed0101,%eax"); |
| __asm__ volatile("movl $0xfeed0202,%ebx"); |
| __asm__ volatile("movl $0xfeed0303,%ecx"); |
| __asm__ volatile("movl $0xfeed0404,%edx"); |
| __asm__ volatile("movl $0xfeed0505,%edi"); |
| __asm__ volatile("movl $0xfeed0606,%esi"); |
| __asm__ volatile("hlt"); |
| __asm__ volatile("movl %0, %%eax" : : "m"(saved_eax)); |
| ran_after_fault++; |
| } |
| |
| void this_function_int3s(void) |
| { |
| int foo; |
| bottom_of_stack = &foo - 4; |
| unsigned long saved_eax; |
| |
| /* Set up registers with known values which will be tested in the signal handler */ |
| __asm__ volatile("movl %%eax, %0" : "=m"(saved_eax)); |
| __asm__ volatile("movl $0xfeed0101,%eax"); |
| __asm__ volatile("movl $0xfeed0202,%ebx"); |
| __asm__ volatile("movl $0xfeed0303,%ecx"); |
| __asm__ volatile("movl $0xfeed0404,%edx"); |
| __asm__ volatile("movl $0xfeed0505,%edi"); |
| __asm__ volatile("movl $0xfeed0606,%esi"); |
| __asm__ volatile("int $3"); |
| __asm__ volatile("movl %0, %%eax" : : "m"(saved_eax)); |
| 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 various registers were saved in the signal ucontext */ |
| ASSERT_EQ(uc->uc_mcontext->__ss.__eax, 0xfeed0101); |
| ASSERT_EQ(uc->uc_mcontext->__ss.__ebx, 0xfeed0202); |
| ASSERT_EQ(uc->uc_mcontext->__ss.__ecx, 0xfeed0303); |
| ASSERT_EQ(uc->uc_mcontext->__ss.__edx, 0xfeed0404); |
| ASSERT_EQ(uc->uc_mcontext->__ss.__edi, 0xfeed0505); |
| ASSERT_EQ(uc->uc_mcontext->__ss.__esi, 0xfeed0606); |
| |
| /* Test that the saved EBP and ESP point into roughly the right |
| * part of the stack */ |
| ASSERT_GTE(uc->uc_mcontext->__ss.__ebp, bottom_of_stack); |
| ASSERT_LTE(uc->uc_mcontext->__ss.__ebp, top_of_stack); |
| ASSERT_GTE(uc->uc_mcontext->__ss.__esp, bottom_of_stack); |
| ASSERT_LTE(uc->uc_mcontext->__ss.__esp, top_of_stack); |
| |
| /* Test that the saved EIP 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.__eip, calling_fn); |
| ASSERT_LTE(uc->uc_mcontext->__ss.__eip, calling_fn+400); |
| |
| /* |
| printf(" RFLAGS 0x%016llx\n", (unsigned long long)uc->uc_mcontext->__ss.__rflags); |
| */ |
| |
| /* |
| * Test that the EIP 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.__eip += (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(); |
| else |
| this_function_halts(); |
| ASSERT_EQ(ran_after_fault, 1); |
| |
| fprintf(stderr, "PASS\n"); |
| return 0; |
| } |