compiler-rt/lib/sanitizer_common/sanitizer_coverage_libcdep_new.cpp

   1 //===-- sanitizer_coverage_libcdep_new.cpp --------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 // Sanitizer Coverage Controller for Trace PC Guard.
   9
  10 #include "sanitizer_platform.h"
  11
  12 #if !SANITIZER_FUCHSIA
  13 #  include "sancov_flags.h"
  14 #  include "sanitizer_allocator_internal.h"
  15 #  include "sanitizer_atomic.h"
  16 #  include "sanitizer_common.h"
  17 #  include "sanitizer_common/sanitizer_stacktrace.h"
  18 #  include "sanitizer_file.h"
  19 #  include "sanitizer_interface_internal.h"
  20
  21 using namespace __sanitizer;
  22
  23 using AddressRange = LoadedModule::AddressRange;
  24
  25 namespace __sancov {
  26 namespace {
  27
  28 static const u64 Magic64 = 0xC0BFFFFFFFFFFF64ULL;
  29 static const u64 Magic32 = 0xC0BFFFFFFFFFFF32ULL;
  30 static const u64 Magic = SANITIZER_WORDSIZE == 64 ? Magic64 : Magic32;
  31
  32 static fd_t OpenFile(const char* path) {
  33   error_t err;
  34   fd_t fd = OpenFile(path, WrOnly, &err);
  35   if (fd == kInvalidFd)
  36     Report("SanitizerCoverage: failed to open %s for writing (reason: %d)\n",
  37            path, err);
  38   return fd;
  39 }
  40
  41 static void GetCoverageFilename(char* path, const char* name,
  42                                 const char* extension) {
  43   CHECK(name);
  44   internal_snprintf(path, kMaxPathLength, "%s/%s.%zd.%s",
  45                     common_flags()->coverage_dir, name, internal_getpid(),
  46                     extension);
  47 }
  48
  49 static void WriteModuleCoverage(char* file_path, const char* module_name,
  50                                 const uptr* pcs, uptr len) {
  51   GetCoverageFilename(file_path, StripModuleName(module_name), "sancov");
  52   fd_t fd = OpenFile(file_path);
  53   WriteToFile(fd, &Magic, sizeof(Magic));
  54   WriteToFile(fd, pcs, len * sizeof(*pcs));
  55   CloseFile(fd);
  56   Printf("SanitizerCoverage: %s: %zd PCs written\n", file_path, len);
  57 }
  58
  59 static void SanitizerDumpCoverage(const uptr* unsorted_pcs, uptr len) {
  60   if (!len) return;
  61
  62   char* file_path = static_cast<char*>(InternalAlloc(kMaxPathLength));
  63   char* module_name = static_cast<char*>(InternalAlloc(kMaxPathLength));
  64   uptr* pcs = static_cast<uptr*>(InternalAlloc(len * sizeof(uptr)));
  65
  66   internal_memcpy(pcs, unsorted_pcs, len * sizeof(uptr));
  67   Sort(pcs, len);
  68
  69   bool module_found = false;
  70   uptr last_base = 0;
  71   uptr module_start_idx = 0;
  72
  73   for (uptr i = 0; i < len; ++i) {
  74     const uptr pc = pcs[i];
  75     if (!pc) continue;
  76
  77     if (!GetModuleAndOffsetForPc(pc, nullptr, 0, &pcs[i])) {
  78       Printf("ERROR: unknown pc 0x%zx (may happen if dlclose is used)\n", pc);
  79       continue;
  80     }
  81     uptr module_base = pc - pcs[i];
  82
  83     if (module_base != last_base || !module_found) {
  84       if (module_found) {
  85         WriteModuleCoverage(file_path, module_name, &pcs[module_start_idx],
  86                             i - module_start_idx);
  87       }
  88
  89       last_base = module_base;
  90       module_start_idx = i;
  91       module_found = true;
  92       GetModuleAndOffsetForPc(pc, module_name, kMaxPathLength, &pcs[i]);
  93     }
  94   }
  95
  96   if (module_found) {
  97     WriteModuleCoverage(file_path, module_name, &pcs[module_start_idx],
  98                         len - module_start_idx);
  99   }
 100
 101   InternalFree(file_path);
 102   InternalFree(module_name);
 103   InternalFree(pcs);
 104 }
 105
 106 // Collects trace-pc guard coverage.
 107 // This class relies on zero-initialization.
 108 class TracePcGuardController {
 109  public:
 110   void Initialize() {
 111     CHECK(!initialized);
 112
 113     initialized = true;
 114     InitializeSancovFlags();
 115
 116     pc_vector.Initialize(0);
 117   }
 118
 119   void InitTracePcGuard(u32* start, u32* end) {
 120     if (!initialized) Initialize();
 121     CHECK(!*start);
 122     CHECK_NE(start, end);
 123
 124     u32 i = pc_vector.size();
 125     for (u32* p = start; p < end; p++) *p = ++i;
 126     pc_vector.resize(i);
 127   }
 128
 129   void TracePcGuard(u32* guard, uptr pc) {
 130     u32 idx = *guard;
 131     if (!idx) return;
 132     // we start indices from 1.
 133     atomic_uintptr_t* pc_ptr =
 134         reinterpret_cast<atomic_uintptr_t*>(&pc_vector[idx - 1]);
 135     if (atomic_load(pc_ptr, memory_order_relaxed) == 0)
 136       atomic_store(pc_ptr, pc, memory_order_relaxed);
 137   }
 138
 139   void Reset() {
 140     internal_memset(&pc_vector[0], 0, sizeof(pc_vector[0]) * pc_vector.size());
 141   }
 142
 143   void Dump() {
 144     if (!initialized || !common_flags()->coverage) return;
 145     __sanitizer_dump_coverage(pc_vector.data(), pc_vector.size());
 146   }
 147
 148  private:
 149   bool initialized;
 150   InternalMmapVectorNoCtor<uptr> pc_vector;
 151 };
 152
 153 static TracePcGuardController pc_guard_controller;
 154
 155 // A basic default implementation of callbacks for
 156 // -fsanitize-coverage=inline-8bit-counters,pc-table.
 157 // Use TOOL_OPTIONS (UBSAN_OPTIONS, etc) to dump the coverage data:
 158 // * cov_8bit_counters_out=PATH to dump the 8bit counters.
 159 // * cov_pcs_out=PATH to dump the pc table.
 160 //
 161 // Most users will still need to define their own callbacks for greater
 162 // flexibility.
 163 namespace SingletonCounterCoverage {
 164
 165 static char *counters_beg, *counters_end;
 166 static const uptr *pcs_beg, *pcs_end;
 167
 168 static void DumpCoverage() {
 169   const char* file_path = common_flags()->cov_8bit_counters_out;
 170   if (file_path && internal_strlen(file_path)) {
 171     fd_t fd = OpenFile(file_path);
 172     FileCloser file_closer(fd);
 173     uptr size = counters_end - counters_beg;
 174     WriteToFile(fd, counters_beg, size);
 175     if (common_flags()->verbosity)
 176       __sanitizer::Printf("cov_8bit_counters_out: written %zd bytes to %s\n",
 177                           size, file_path);
 178   }
 179   file_path = common_flags()->cov_pcs_out;
 180   if (file_path && internal_strlen(file_path)) {
 181     fd_t fd = OpenFile(file_path);
 182     FileCloser file_closer(fd);
 183     uptr size = (pcs_end - pcs_beg) * sizeof(uptr);
 184     WriteToFile(fd, pcs_beg, size);
 185     if (common_flags()->verbosity)
 186       __sanitizer::Printf("cov_pcs_out: written %zd bytes to %s\n", size,
 187                           file_path);
 188   }
 189 }
 190
 191 static void Cov8bitCountersInit(char* beg, char* end) {
 192   counters_beg = beg;
 193   counters_end = end;
 194   Atexit(DumpCoverage);
 195 }
 196
 197 static void CovPcsInit(const uptr* beg, const uptr* end) {
 198   pcs_beg = beg;
 199   pcs_end = end;
 200 }
 201
 202 }  // namespace SingletonCounterCoverage
 203
 204 }  // namespace
 205 }  // namespace __sancov
 206
 207 namespace __sanitizer {
 208 void InitializeCoverage(bool enabled, const char *dir) {
 209   static bool coverage_enabled = false;
 210   if (coverage_enabled)
 211     return;  // May happen if two sanitizer enable coverage in the same process.
 212   coverage_enabled = enabled;
 213   Atexit(__sanitizer_cov_dump);
 214   AddDieCallback(__sanitizer_cov_dump);
 215 }
 216 } // namespace __sanitizer
 217
 218 extern "C" {
 219 SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_dump_coverage(const uptr* pcs,
 220                                                              uptr len) {
 221   return __sancov::SanitizerDumpCoverage(pcs, len);
 222 }
 223
 224 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_pc_guard, u32* guard) {
 225   if (!*guard) return;
 226   __sancov::pc_guard_controller.TracePcGuard(
 227       guard, StackTrace::GetPreviousInstructionPc(GET_CALLER_PC()));
 228 }
 229
 230 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_pc_guard_init,
 231                              u32* start, u32* end) {
 232   if (start == end || *start) return;
 233   __sancov::pc_guard_controller.InitTracePcGuard(start, end);
 234 }
 235
 236 SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_dump_trace_pc_guard_coverage() {
 237   __sancov::pc_guard_controller.Dump();
 238 }
 239 SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov_dump() {
 240   __sanitizer_dump_trace_pc_guard_coverage();
 241 }
 242 SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov_reset() {
 243   __sancov::pc_guard_controller.Reset();
 244 }
 245 // Default implementations (weak).
 246 // Either empty or very simple.
 247 // Most users should redefine them.
 248 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_cmp, void) {}
 249 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_cmp1, void) {}
 250 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_cmp2, void) {}
 251 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_cmp4, void) {}
 252 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_cmp8, void) {}
 253 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_const_cmp1, void) {}
 254 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_const_cmp2, void) {}
 255 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_const_cmp4, void) {}
 256 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_const_cmp8, void) {}
 257 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_switch, void) {}
 258 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_div4, void) {}
 259 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_div8, void) {}
 260 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_gep, void) {}
 261 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_pc_indir, void) {}
 262 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_8bit_counters_init,
 263                              char* start, char* end) {
 264   __sancov::SingletonCounterCoverage::Cov8bitCountersInit(start, end);
 265 }
 266 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_bool_flag_init, void) {}
 267 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_pcs_init, const uptr* beg,
 268                              const uptr* end) {
 269   __sancov::SingletonCounterCoverage::CovPcsInit(beg, end);
 270 }
 271 }  // extern "C"
 272 // Weak definition for code instrumented with -fsanitize-coverage=stack-depth
 273 // and later linked with code containing a strong definition.
 274 // E.g., -fsanitize=fuzzer-no-link
 275 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 276 SANITIZER_TLS_INITIAL_EXEC_ATTRIBUTE uptr __sancov_lowest_stack;
 277
 278 #endif  // !SANITIZER_FUCHSIA