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1// Check that ASan plays well with easy cases of makecontext/swapcontext.2 3// RUN: %clangxx_asan -O0 %s -o %t && %run %t4// RUN: %clangxx_asan -O3 %s -o %t && %run %t5// RUN: %clangxx_asan -fsanitize-address-use-after-return=never -O0 %s -o %t && %run %t6// RUN: %clangxx_asan -fsanitize-address-use-after-return=never -O3 %s -o %t && %run %t7//8// This test is too sublte to try on non-x86 arch for now.9// Android and musl do not support swapcontext.10// REQUIRES: x86-target-arch && glibc-2.2711 12#include <assert.h>13#include <memory.h>14#include <stdio.h>15#include <ucontext.h>16#include <unistd.h>17 18ucontext_t orig_context;19ucontext_t child_context;20 21const int kStackSize = 1 << 20;22 23__attribute__((noinline)) void Throw() { throw 1; }24 25__attribute__((noinline)) void ThrowAndCatch() {26  try {27    Throw();28  } catch (int a) {29    printf("ThrowAndCatch: %d\n", a);30  }31}32 33void Child(int mode, int a, int b, int c) {34  char x[32] = {0}; // Stack gets poisoned.35  printf("Child: %d\n", x);36  assert(a == 'a');37  assert(b == 'b');38  assert(c == 'c');39  ThrowAndCatch(); // Simulate __asan_handle_no_return().40  // (a) Do nothing, just return to parent function.41  // (b) Jump into the original function. Stack remains poisoned unless we do42  //     something.43  if (mode == 1) {44    if (swapcontext(&child_context, &orig_context) < 0) {45      perror("swapcontext");46      _exit(0);47    }48  }49}50 51int Run(int arg, int mode, char *child_stack) {52  printf("Child stack: %p\n", child_stack);53  // Setup child context.54  getcontext(&child_context);55  child_context.uc_stack.ss_sp = child_stack;56  child_context.uc_stack.ss_size = kStackSize / 2;57  if (mode == 0) {58    child_context.uc_link = &orig_context;59  }60  makecontext(&child_context, (void (*)())Child, 4, mode, 'a', 'b', 'c');61  if (swapcontext(&orig_context, &child_context) < 0) {62    perror("swapcontext");63    return 0;64  }65  // Touch childs's stack to make sure it's unpoisoned.66  for (int i = 0; i < kStackSize; i++) {67    child_stack[i] = i;68  }69  return child_stack[arg];70}71 72ucontext_t poll_context;73ucontext_t poller_context;74 75void Poll() {76  swapcontext(&poll_context, &poller_context);77 78  {79    char x = 0;80    printf("POLL: %p\n", &x);81  }82 83  swapcontext(&poll_context, &poller_context);84}85 86void DoRunPoll(char *poll_stack) {87  getcontext(&poll_context);88  poll_context.uc_stack.ss_sp = poll_stack;89  poll_context.uc_stack.ss_size = kStackSize / 2;90  makecontext(&poll_context, Poll, 0);91 92  getcontext(&poller_context);93 94  swapcontext(&poller_context, &poll_context);95  swapcontext(&poller_context, &poll_context);96 97  // Touch poll's stack to make sure it's unpoisoned.98  for (int i = 0; i < kStackSize; i++) {99    poll_stack[i] = i;100  }101}102 103void RunPoll() {104  char *poll_stack = new char[kStackSize];105 106  for (size_t i = 0; i < 2; ++i) {107    DoRunPoll(poll_stack);108  }109 110  delete[] poll_stack;111}112 113int main(int argc, char **argv) {114  char stack[kStackSize + 1];115  int ret = 0;116  ret += Run(argc - 1, 0, stack);117  ret += Run(argc - 1, 1, stack);118  char *heap = new char[kStackSize + 1];119  ret += Run(argc - 1, 0, heap);120  ret += Run(argc - 1, 1, heap);121 122  RunPoll();123  delete[] heap;124  return ret;125}126