193 lines · cpp
1//===-- sanitizer_procmaps_common.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-exception6//7//===----------------------------------------------------------------------===//8//9// Information about the process mappings (common parts).10//===----------------------------------------------------------------------===//11 12#include "sanitizer_platform.h"13 14#if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD || \15 SANITIZER_SOLARIS16 17#include "sanitizer_common.h"18#include "sanitizer_placement_new.h"19#include "sanitizer_procmaps.h"20 21namespace __sanitizer {22 23static ProcSelfMapsBuff cached_proc_self_maps;24static StaticSpinMutex cache_lock;25 26static int TranslateDigit(char c) {27 if (c >= '0' && c <= '9')28 return c - '0';29 if (c >= 'a' && c <= 'f')30 return c - 'a' + 10;31 if (c >= 'A' && c <= 'F')32 return c - 'A' + 10;33 return -1;34}35 36// Parse a number and promote 'p' up to the first non-digit character.37static uptr ParseNumber(const char **p, int base) {38 uptr n = 0;39 int d;40 CHECK(base >= 2 && base <= 16);41 while ((d = TranslateDigit(**p)) >= 0 && d < base) {42 n = n * base + d;43 (*p)++;44 }45 return n;46}47 48bool IsDecimal(char c) {49 int d = TranslateDigit(c);50 return d >= 0 && d < 10;51}52 53uptr ParseDecimal(const char **p) {54 return ParseNumber(p, 10);55}56 57bool IsHex(char c) {58 int d = TranslateDigit(c);59 return d >= 0 && d < 16;60}61 62uptr ParseHex(const char **p) {63 return ParseNumber(p, 16);64}65 66void MemoryMappedSegment::AddAddressRanges(LoadedModule *module) {67 // data_ should be unused on this platform68 CHECK(!data_);69 module->addAddressRange(start, end, IsExecutable(), IsWritable());70}71 72MemoryMappingLayout::MemoryMappingLayout(bool cache_enabled) {73 // FIXME: in the future we may want to cache the mappings on demand only.74 if (cache_enabled)75 CacheMemoryMappings();76 77 // Read maps after the cache update to capture the maps/unmaps happening in78 // the process of updating.79 ReadProcMaps(&data_.proc_self_maps);80 if (cache_enabled && data_.proc_self_maps.mmaped_size == 0)81 LoadFromCache();82 83 Reset();84}85 86bool MemoryMappingLayout::Error() const {87 return data_.current == nullptr;88}89 90MemoryMappingLayout::~MemoryMappingLayout() {91 // Only unmap the buffer if it is different from the cached one. Otherwise92 // it will be unmapped when the cache is refreshed.93 if (data_.proc_self_maps.data != cached_proc_self_maps.data)94 UnmapOrDie(data_.proc_self_maps.data, data_.proc_self_maps.mmaped_size);95}96 97void MemoryMappingLayout::Reset() {98 data_.current = data_.proc_self_maps.data;99}100 101// static102void MemoryMappingLayout::CacheMemoryMappings() {103 ProcSelfMapsBuff new_proc_self_maps;104 ReadProcMaps(&new_proc_self_maps);105 // Don't invalidate the cache if the mappings are unavailable.106 if (new_proc_self_maps.mmaped_size == 0)107 return;108 SpinMutexLock l(&cache_lock);109 if (cached_proc_self_maps.mmaped_size)110 UnmapOrDie(cached_proc_self_maps.data, cached_proc_self_maps.mmaped_size);111 cached_proc_self_maps = new_proc_self_maps;112}113 114void MemoryMappingLayout::LoadFromCache() {115 SpinMutexLock l(&cache_lock);116 if (cached_proc_self_maps.data)117 data_.proc_self_maps = cached_proc_self_maps;118}119 120void MemoryMappingLayout::DumpListOfModules(121 InternalMmapVectorNoCtor<LoadedModule> *modules) {122 Reset();123 InternalMmapVector<char> module_name(kMaxPathLength);124 MemoryMappedSegment segment(module_name.data(), module_name.size());125 for (uptr i = 0; Next(&segment); i++) {126 const char *cur_name = segment.filename;127 if (cur_name[0] == '\0')128 continue;129 // Don't subtract 'cur_beg' from the first entry:130 // * If a binary is compiled w/o -pie, then the first entry in131 // process maps is likely the binary itself (all dynamic libs132 // are mapped higher in address space). For such a binary,133 // instruction offset in binary coincides with the actual134 // instruction address in virtual memory (as code section135 // is mapped to a fixed memory range).136 // * If a binary is compiled with -pie, all the modules are137 // mapped high at address space (in particular, higher than138 // shadow memory of the tool), so the module can't be the139 // first entry.140 uptr base_address = (i ? segment.start : 0) - segment.offset;141 LoadedModule cur_module;142 cur_module.set(cur_name, base_address);143 segment.AddAddressRanges(&cur_module);144 modules->push_back(cur_module);145 }146}147 148#if SANITIZER_LINUX || SANITIZER_ANDROID || SANITIZER_SOLARIS149void GetMemoryProfile(fill_profile_f cb, uptr *stats) {150 char *smaps = nullptr;151 uptr smaps_cap = 0;152 uptr smaps_len = 0;153 if (!ReadFileToBuffer("/proc/self/smaps", &smaps, &smaps_cap, &smaps_len))154 return;155 ParseUnixMemoryProfile(cb, stats, smaps, smaps_len);156 UnmapOrDie(smaps, smaps_cap);157}158 159void ParseUnixMemoryProfile(fill_profile_f cb, uptr *stats, char *smaps,160 uptr smaps_len) {161 uptr start = 0;162 bool file = false;163 const char *pos = smaps;164 char *end = smaps + smaps_len;165 if (smaps_len < 2)166 return;167 // The following parsing can crash on almost every line168 // in the case of malformed/truncated input.169 // Fixing that is hard b/c e.g. ParseDecimal does not170 // even accept end of the buffer and assumes well-formed input.171 // So instead we patch end of the input a bit,172 // it does not affect well-formed complete inputs.173 *--end = 0;174 *--end = '\n';175 while (pos < end) {176 if (IsHex(pos[0])) {177 start = ParseHex(&pos);178 for (; *pos != '/' && *pos > '\n'; pos++) {}179 file = *pos == '/';180 } else if (internal_strncmp(pos, "Rss:", 4) == 0) {181 while (pos < end && !IsDecimal(*pos)) pos++;182 uptr rss = ParseDecimal(&pos) * 1024;183 cb(start, rss, file, stats);184 }185 while (*pos++ != '\n') {}186 }187}188#endif189 190} // namespace __sanitizer191 192#endif193