sanitizer_coverage_mapping_libcdep.cc revision 6d1862363c88c183b0ed7740fca876342cf0474b
1//===-- sanitizer_coverage_mapping.cc -------------------------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// Mmap-based implementation of sanitizer coverage. 11// 12// This is part of the implementation of code coverage that does not require 13// __sanitizer_cov_dump() call. Data is stored in 2 files per process. 14// 15// $pid.sancov.map describes process memory layout in the following text-based 16// format: 17// <pointer size in bits> // 1 line, 32 or 64 18// <mapping start> <mapping end> <base address> <dso name> // repeated 19// ... 20// Mapping lines are NOT sorted. This file is updated every time memory layout 21// is changed (i.e. in dlopen() and dlclose() interceptors). 22// 23// $pid.sancov.raw is a binary dump of PC values, sizeof(uptr) each. Again, not 24// sorted. This file is extended by 64Kb at a time and mapped into memory. It 25// contains one or more 0 words at the end, up to the next 64Kb aligned offset. 26// 27// To convert these 2 files to the usual .sancov format, run sancov.py rawunpack 28// $pid.sancov.raw. 29// 30//===----------------------------------------------------------------------===// 31 32#include "sanitizer_allocator_internal.h" 33#include "sanitizer_libc.h" 34#include "sanitizer_procmaps.h" 35 36namespace __sanitizer { 37 38static const uptr kMaxNumberOfModules = 1 << 14; 39static const uptr kMaxTextSize = 64 * 1024; 40 41struct CachedMapping { 42 public: 43 bool NeedsUpdate(uptr pc) { 44 int new_pid = internal_getpid(); 45 if (last_pid == new_pid && pc && pc >= last_range_start && 46 pc < last_range_end) 47 return false; 48 last_pid = new_pid; 49 return true; 50 } 51 52 void SetModuleRange(uptr start, uptr end) { 53 last_range_start = start; 54 last_range_end = end; 55 } 56 57 private: 58 uptr last_range_start, last_range_end; 59 int last_pid; 60}; 61 62static CachedMapping cached_mapping; 63static StaticSpinMutex mapping_mu; 64 65void CovUpdateMapping(uptr caller_pc) { 66 if (!common_flags()->coverage || !common_flags()->coverage_direct) return; 67 68 SpinMutexLock l(&mapping_mu); 69 70 if (!cached_mapping.NeedsUpdate(caller_pc)) 71 return; 72 73 InternalScopedString text(kMaxTextSize); 74 InternalScopedBuffer<char> modules_data(kMaxNumberOfModules * 75 sizeof(LoadedModule)); 76 LoadedModule *modules = (LoadedModule *)modules_data.data(); 77 CHECK(modules); 78 int n_modules = GetListOfModules(modules, kMaxNumberOfModules, 79 /* filter */ 0); 80 81 text.append("%d\n", sizeof(uptr) * 8); 82 for (int i = 0; i < n_modules; ++i) { 83 const char *module_name = StripModuleName(modules[i].full_name()); 84 for (unsigned j = 0; j < modules[i].n_ranges(); ++j) { 85 if (modules[i].address_range_executable(j)) { 86 uptr start = modules[i].address_range_start(j); 87 uptr end = modules[i].address_range_end(j); 88 uptr base = modules[i].base_address(); 89 text.append("%zx %zx %zx %s\n", start, end, base, module_name); 90 if (caller_pc && caller_pc >= start && caller_pc < end) 91 cached_mapping.SetModuleRange(start, end); 92 } 93 } 94 } 95 96 int err; 97 InternalScopedString tmp_path(64 + 98 internal_strlen(common_flags()->coverage_dir)); 99 uptr res = internal_snprintf((char *)tmp_path.data(), tmp_path.size(), 100 "%s/%zd.sancov.map.tmp", common_flags()->coverage_dir, 101 internal_getpid()); 102 CHECK_LE(res, tmp_path.size()); 103 uptr map_fd = OpenFile(tmp_path.data(), true); 104 if (internal_iserror(map_fd)) { 105 Report(" Coverage: failed to open %s for writing\n", tmp_path.data()); 106 Die(); 107 } 108 109 res = internal_write(map_fd, text.data(), text.length()); 110 if (internal_iserror(res, &err)) { 111 Printf("sancov.map write failed: %d\n", err); 112 Die(); 113 } 114 internal_close(map_fd); 115 116 InternalScopedString path(64 + internal_strlen(common_flags()->coverage_dir)); 117 res = internal_snprintf((char *)path.data(), path.size(), "%s/%zd.sancov.map", 118 common_flags()->coverage_dir, internal_getpid()); 119 CHECK_LE(res, path.size()); 120 res = internal_rename(tmp_path.data(), path.data()); 121 if (internal_iserror(res, &err)) { 122 Printf("sancov.map rename failed: %d\n", err); 123 Die(); 124 } 125} 126 127} // namespace __sanitizer 128