1 //===-- sanitizer_procmaps_common.cc --------------------------------------===//
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
7 //===----------------------------------------------------------------------===//
9 // Information about the process mappings (common parts).
10 //===----------------------------------------------------------------------===//
12 #include "sanitizer_platform.h"
14 #if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD || \
15 SANITIZER_OPENBSD || SANITIZER_SOLARIS
17 #include "sanitizer_common.h"
18 #include "sanitizer_placement_new.h"
19 #include "sanitizer_procmaps.h"
21 namespace __sanitizer {
23 static ProcSelfMapsBuff cached_proc_self_maps;
24 static StaticSpinMutex cache_lock;
26 static int TranslateDigit(char c) {
27 if (c >= '0' && c <= '9')
29 if (c >= 'a' && c <= 'f')
31 if (c >= 'A' && c <= 'F')
36 // Parse a number and promote 'p' up to the first non-digit character.
37 static uptr ParseNumber(const char **p, int base) {
40 CHECK(base >= 2 && base <= 16);
41 while ((d = TranslateDigit(**p)) >= 0 && d < base) {
48 bool IsDecimal(char c) {
49 int d = TranslateDigit(c);
50 return d >= 0 && d < 10;
53 uptr ParseDecimal(const char **p) {
54 return ParseNumber(p, 10);
58 int d = TranslateDigit(c);
59 return d >= 0 && d < 16;
62 uptr ParseHex(const char **p) {
63 return ParseNumber(p, 16);
66 void MemoryMappedSegment::AddAddressRanges(LoadedModule *module) {
67 // data_ should be unused on this platform
69 module->addAddressRange(start, end, IsExecutable(), IsWritable());
72 MemoryMappingLayout::MemoryMappingLayout(bool cache_enabled) {
73 // FIXME: in the future we may want to cache the mappings on demand only.
75 CacheMemoryMappings();
77 // Read maps after the cache update to capture the maps/unmaps happening in
78 // the process of updating.
79 ReadProcMaps(&data_.proc_self_maps);
80 if (cache_enabled && data_.proc_self_maps.mmaped_size == 0)
86 bool MemoryMappingLayout::Error() const {
87 return data_.current == nullptr;
90 MemoryMappingLayout::~MemoryMappingLayout() {
91 // Only unmap the buffer if it is different from the cached one. Otherwise
92 // 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);
97 void MemoryMappingLayout::Reset() {
98 data_.current = data_.proc_self_maps.data;
102 void 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)
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;
114 void MemoryMappingLayout::LoadFromCache() {
115 SpinMutexLock l(&cache_lock);
116 if (cached_proc_self_maps.data)
117 data_.proc_self_maps = cached_proc_self_maps;
120 void MemoryMappingLayout::DumpListOfModules(
121 InternalMmapVectorNoCtor<LoadedModule> *modules) {
123 InternalScopedString 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')
129 // Don't subtract 'cur_beg' from the first entry:
130 // * If a binary is compiled w/o -pie, then the first entry in
131 // process maps is likely the binary itself (all dynamic libs
132 // are mapped higher in address space). For such a binary,
133 // instruction offset in binary coincides with the actual
134 // instruction address in virtual memory (as code section
135 // is mapped to a fixed memory range).
136 // * If a binary is compiled with -pie, all the modules are
137 // mapped high at address space (in particular, higher than
138 // shadow memory of the tool), so the module can't be the
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);
148 void GetMemoryProfile(fill_profile_f cb, uptr *stats, uptr stats_size) {
149 char *smaps = nullptr;
152 if (!ReadFileToBuffer("/proc/self/smaps", &smaps, &smaps_cap, &smaps_len))
156 const char *pos = smaps;
157 while (pos < smaps + smaps_len) {
159 start = ParseHex(&pos);
160 for (; *pos != '/' && *pos > '\n'; pos++) {}
162 } else if (internal_strncmp(pos, "Rss:", 4) == 0) {
163 while (!IsDecimal(*pos)) pos++;
164 uptr rss = ParseDecimal(&pos) * 1024;
165 cb(start, rss, file, stats, stats_size);
167 while (*pos++ != '\n') {}
169 UnmapOrDie(smaps, smaps_cap);
172 } // namespace __sanitizer