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//===-- sanitizer_procmaps_common.cpp -------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Information about the process mappings (common parts).
//===----------------------------------------------------------------------===//
#include "sanitizer_platform.h"
#if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD || \
SANITIZER_SOLARIS
#include "sanitizer_common.h"
#include "sanitizer_placement_new.h"
#include "sanitizer_procmaps.h"
namespace __sanitizer {
static ProcSelfMapsBuff cached_proc_self_maps;
static StaticSpinMutex cache_lock;
static int TranslateDigit(char c) {
if (c >= '0' && c <= '9')
return c - '0';
if (c >= 'a' && c <= 'f')
return c - 'a' + 10;
if (c >= 'A' && c <= 'F')
return c - 'A' + 10;
return -1;
}
// Parse a number and promote 'p' up to the first non-digit character.
static uptr ParseNumber(const char **p, int base) {
uptr n = 0;
int d;
CHECK(base >= 2 && base <= 16);
while ((d = TranslateDigit(**p)) >= 0 && d < base) {
n = n * base + d;
(*p)++;
}
return n;
}
bool IsDecimal(char c) {
int d = TranslateDigit(c);
return d >= 0 && d < 10;
}
uptr ParseDecimal(const char **p) {
return ParseNumber(p, 10);
}
bool IsHex(char c) {
int d = TranslateDigit(c);
return d >= 0 && d < 16;
}
uptr ParseHex(const char **p) {
return ParseNumber(p, 16);
}
void MemoryMappedSegment::AddAddressRanges(LoadedModule *module) {
// data_ should be unused on this platform
CHECK(!data_);
module->addAddressRange(start, end, IsExecutable(), IsWritable());
}
MemoryMappingLayout::MemoryMappingLayout(bool cache_enabled) {
// FIXME: in the future we may want to cache the mappings on demand only.
if (cache_enabled)
CacheMemoryMappings();
// Read maps after the cache update to capture the maps/unmaps happening in
// the process of updating.
ReadProcMaps(&data_.proc_self_maps);
if (cache_enabled && data_.proc_self_maps.mmaped_size == 0)
LoadFromCache();
Reset();
}
bool MemoryMappingLayout::Error() const {
return data_.current == nullptr;
}
MemoryMappingLayout::~MemoryMappingLayout() {
// Only unmap the buffer if it is different from the cached one. Otherwise
// it will be unmapped when the cache is refreshed.
if (data_.proc_self_maps.data != cached_proc_self_maps.data)
UnmapOrDie(data_.proc_self_maps.data, data_.proc_self_maps.mmaped_size);
}
void MemoryMappingLayout::Reset() {
data_.current = data_.proc_self_maps.data;
}
// static
void MemoryMappingLayout::CacheMemoryMappings() {
ProcSelfMapsBuff new_proc_self_maps;
ReadProcMaps(&new_proc_self_maps);
// Don't invalidate the cache if the mappings are unavailable.
if (new_proc_self_maps.mmaped_size == 0)
return;
SpinMutexLock l(&cache_lock);
if (cached_proc_self_maps.mmaped_size)
UnmapOrDie(cached_proc_self_maps.data, cached_proc_self_maps.mmaped_size);
cached_proc_self_maps = new_proc_self_maps;
}
void MemoryMappingLayout::LoadFromCache() {
SpinMutexLock l(&cache_lock);
if (cached_proc_self_maps.data)
data_.proc_self_maps = cached_proc_self_maps;
}
void MemoryMappingLayout::DumpListOfModules(
InternalMmapVectorNoCtor<LoadedModule> *modules) {
Reset();
InternalMmapVector<char> module_name(kMaxPathLength);
MemoryMappedSegment segment(module_name.data(), module_name.size());
for (uptr i = 0; Next(&segment); i++) {
const char *cur_name = segment.filename;
if (cur_name[0] == '\0')
continue;
// Don't subtract 'cur_beg' from the first entry:
// * If a binary is compiled w/o -pie, then the first entry in
// process maps is likely the binary itself (all dynamic libs
// are mapped higher in address space). For such a binary,
// instruction offset in binary coincides with the actual
// instruction address in virtual memory (as code section
// is mapped to a fixed memory range).
// * If a binary is compiled with -pie, all the modules are
// mapped high at address space (in particular, higher than
// shadow memory of the tool), so the module can't be the
// first entry.
uptr base_address = (i ? segment.start : 0) - segment.offset;
LoadedModule cur_module;
cur_module.set(cur_name, base_address);
segment.AddAddressRanges(&cur_module);
modules->push_back(cur_module);
}
}
void GetMemoryProfile(fill_profile_f cb, uptr *stats) {
char *smaps = nullptr;
uptr smaps_cap = 0;
uptr smaps_len = 0;
if (!ReadFileToBuffer("/proc/self/smaps", &smaps, &smaps_cap, &smaps_len))
return;
ParseUnixMemoryProfile(cb, stats, smaps, smaps_len);
UnmapOrDie(smaps, smaps_cap);
}
void ParseUnixMemoryProfile(fill_profile_f cb, uptr *stats, char *smaps,
uptr smaps_len) {
uptr start = 0;
bool file = false;
const char *pos = smaps;
char *end = smaps + smaps_len;
if (smaps_len < 2)
return;
// The following parsing can crash on almost every line
// in the case of malformed/truncated input.
// Fixing that is hard b/c e.g. ParseDecimal does not
// even accept end of the buffer and assumes well-formed input.
// So instead we patch end of the input a bit,
// it does not affect well-formed complete inputs.
*--end = 0;
*--end = '\n';
while (pos < end) {
if (IsHex(pos[0])) {
start = ParseHex(&pos);
for (; *pos != '/' && *pos > '\n'; pos++) {}
file = *pos == '/';
} else if (internal_strncmp(pos, "Rss:", 4) == 0) {
while (pos < end && !IsDecimal(*pos)) pos++;
uptr rss = ParseDecimal(&pos) * 1024;
cb(start, rss, file, stats);
}
while (*pos++ != '\n') {}
}
}
} // namespace __sanitizer
#endif
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