libsanitizer/sanitizer_common/sanitizer_coverage_libcdep_new.cc

   1 //===-- sanitizer_coverage_libcdep_new.cc ---------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 // Sanitizer Coverage Controller for Trace PC Guard.
   8
   9 #include "sanitizer_platform.h"
  10
  11 #if !SANITIZER_FUCHSIA
  12 #include "sancov_flags.h"
  13 #include "sanitizer_allocator_internal.h"
  14 #include "sanitizer_atomic.h"
  15 #include "sanitizer_common.h"
  16 #include "sanitizer_file.h"
  17
  18 using namespace __sanitizer;
  19
  20 using AddressRange = LoadedModule::AddressRange;
  21
  22 namespace __sancov {
  23 namespace {
  24
  25 static const u64 Magic64 = 0xC0BFFFFFFFFFFF64ULL;
  26 static const u64 Magic32 = 0xC0BFFFFFFFFFFF32ULL;
  27 static const u64 Magic = SANITIZER_WORDSIZE == 64 ? Magic64 : Magic32;
  28
  29 static fd_t OpenFile(const char* path) {
  30   error_t err;
  31   fd_t fd = OpenFile(path, WrOnly, &err);
  32   if (fd == kInvalidFd)
  33     Report("SanitizerCoverage: failed to open %s for writing (reason: %d)\n",
  34            path, err);
  35   return fd;
  36 }
  37
  38 static void GetCoverageFilename(char* path, const char* name,
  39                                 const char* extension) {
  40   CHECK(name);
  41   internal_snprintf(path, kMaxPathLength, "%s/%s.%zd.%s",
  42                     common_flags()->coverage_dir, name, internal_getpid(),
  43                     extension);
  44 }
  45
  46 static void WriteModuleCoverage(char* file_path, const char* module_name,
  47                                 const uptr* pcs, uptr len) {
  48   GetCoverageFilename(file_path, StripModuleName(module_name), "sancov");
  49   fd_t fd = OpenFile(file_path);
  50   WriteToFile(fd, &Magic, sizeof(Magic));
  51   WriteToFile(fd, pcs, len * sizeof(*pcs));
  52   CloseFile(fd);
  53   Printf("SanitizerCoverage: %s: %zd PCs written\n", file_path, len);
  54 }
  55
  56 static void SanitizerDumpCoverage(const uptr* unsorted_pcs, uptr len) {
  57   if (!len) return;
  58
  59   char* file_path = static_cast<char*>(InternalAlloc(kMaxPathLength));
  60   char* module_name = static_cast<char*>(InternalAlloc(kMaxPathLength));
  61   uptr* pcs = static_cast<uptr*>(InternalAlloc(len * sizeof(uptr)));
  62
  63   internal_memcpy(pcs, unsorted_pcs, len * sizeof(uptr));
  64   Sort(pcs, len);
  65
  66   bool module_found = false;
  67   uptr last_base = 0;
  68   uptr module_start_idx = 0;
  69
  70   for (uptr i = 0; i < len; ++i) {
  71     const uptr pc = pcs[i];
  72     if (!pc) continue;
  73
  74     if (!__sanitizer_get_module_and_offset_for_pc(pc, nullptr, 0, &pcs[i])) {
  75       Printf("ERROR: unknown pc 0x%x (may happen if dlclose is used)\n", pc);
  76       continue;
  77     }
  78     uptr module_base = pc - pcs[i];
  79
  80     if (module_base != last_base || !module_found) {
  81       if (module_found) {
  82         WriteModuleCoverage(file_path, module_name, &pcs[module_start_idx],
  83                             i - module_start_idx);
  84       }
  85
  86       last_base = module_base;
  87       module_start_idx = i;
  88       module_found = true;
  89       __sanitizer_get_module_and_offset_for_pc(pc, module_name, kMaxPathLength,
  90                                                &pcs[i]);
  91     }
  92   }
  93
  94   if (module_found) {
  95     WriteModuleCoverage(file_path, module_name, &pcs[module_start_idx],
  96                         len - module_start_idx);
  97   }
  98
  99   InternalFree(file_path);
 100   InternalFree(module_name);
 101   InternalFree(pcs);
 102 }
 103
 104 // Collects trace-pc guard coverage.
 105 // This class relies on zero-initialization.
 106 class TracePcGuardController {
 107  public:
 108   void Initialize() {
 109     CHECK(!initialized);
 110
 111     initialized = true;
 112     InitializeSancovFlags();
 113
 114     pc_vector.Initialize(0);
 115   }
 116
 117   void InitTracePcGuard(u32* start, u32* end) {
 118     if (!initialized) Initialize();
 119     CHECK(!*start);
 120     CHECK_NE(start, end);
 121
 122     u32 i = pc_vector.size();
 123     for (u32* p = start; p < end; p++) *p = ++i;
 124     pc_vector.resize(i);
 125   }
 126
 127   void TracePcGuard(u32* guard, uptr pc) {
 128     u32 idx = *guard;
 129     if (!idx) return;
 130     // we start indices from 1.
 131     atomic_uintptr_t* pc_ptr =
 132         reinterpret_cast<atomic_uintptr_t*>(&pc_vector[idx - 1]);
 133     if (atomic_load(pc_ptr, memory_order_relaxed) == 0)
 134       atomic_store(pc_ptr, pc, memory_order_relaxed);
 135   }
 136
 137   void Reset() {
 138     internal_memset(&pc_vector[0], 0, sizeof(pc_vector[0]) * pc_vector.size());
 139   }
 140
 141   void Dump() {
 142     if (!initialized || !common_flags()->coverage) return;
 143     __sanitizer_dump_coverage(pc_vector.data(), pc_vector.size());
 144   }
 145
 146  private:
 147   bool initialized;
 148   InternalMmapVectorNoCtor<uptr> pc_vector;
 149 };
 150
 151 static TracePcGuardController pc_guard_controller;
 152
 153 }  // namespace
 154 }  // namespace __sancov
 155
 156 namespace __sanitizer {
 157 void InitializeCoverage(bool enabled, const char *dir) {
 158   static bool coverage_enabled = false;
 159   if (coverage_enabled)
 160     return;  // May happen if two sanitizer enable coverage in the same process.
 161   coverage_enabled = enabled;
 162   Atexit(__sanitizer_cov_dump);
 163   AddDieCallback(__sanitizer_cov_dump);
 164 }
 165 } // namespace __sanitizer
 166
 167 extern "C" {
 168 SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_dump_coverage(  // NOLINT
 169     const uptr* pcs, uptr len) {
 170   return __sancov::SanitizerDumpCoverage(pcs, len);
 171 }
 172
 173 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_pc_guard, u32* guard) {
 174   if (!*guard) return;
 175   __sancov::pc_guard_controller.TracePcGuard(guard, GET_CALLER_PC() - 1);
 176 }
 177
 178 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_pc_guard_init,
 179                              u32* start, u32* end) {
 180   if (start == end || *start) return;
 181   __sancov::pc_guard_controller.InitTracePcGuard(start, end);
 182 }
 183
 184 SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_dump_trace_pc_guard_coverage() {
 185   __sancov::pc_guard_controller.Dump();
 186 }
 187 SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov_dump() {
 188   __sanitizer_dump_trace_pc_guard_coverage();
 189 }
 190 SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov_reset() {
 191   __sancov::pc_guard_controller.Reset();
 192 }
 193 // Default empty implementations (weak). Users should redefine them.
 194 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_cmp, void) {}
 195 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_cmp1, void) {}
 196 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_cmp2, void) {}
 197 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_cmp4, void) {}
 198 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_cmp8, void) {}
 199 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_const_cmp1, void) {}
 200 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_const_cmp2, void) {}
 201 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_const_cmp4, void) {}
 202 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_const_cmp8, void) {}
 203 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_switch, void) {}
 204 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_div4, void) {}
 205 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_div8, void) {}
 206 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_gep, void) {}
 207 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_pc_indir, void) {}
 208 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_8bit_counters_init, void) {}
 209 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_pcs_init, void) {}
 210 }  // extern "C"
 211 // Weak definition for code instrumented with -fsanitize-coverage=stack-depth
 212 // and later linked with code containing a strong definition.
 213 // E.g., -fsanitize=fuzzer-no-link
 214 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 215 SANITIZER_TLS_INITIAL_EXEC_ATTRIBUTE uptr __sancov_lowest_stack;
 216
 217 #endif  // !SANITIZER_FUCHSIA