std::string CaptureFD::readIncremental() {
std::string filename = file_.path().string();
// Yes, I know that I could just keep the file open instead. So sue me.
folly::File f(openNoInt(filename.c_str(), O_RDONLY), true);
auto size = size_t(lseek(f.fd(), 0, SEEK_END) - readOffset_);
std::unique_ptr<char[]> buf(new char[size]);
auto bytes_read = folly::preadFull(f.fd(), buf.get(), size, readOffset_);
PCHECK(ssize_t(size) == bytes_read);
readOffset_ += off_t(size);
chunkCob_(StringPiece(buf.get(), buf.get() + size));
return std::string(buf.get(), size);
}
Symbolizer::Symbolizer(ElfCacheBase* cache)
: cache_(cache ?: defaultElfCache()) {
}
void Symbolizer::symbolize(const uintptr_t* addresses,
SymbolizedFrame* frames,
size_t addressCount) {
size_t remaining = 0;
for (size_t i = 0; i < addressCount; ++i) {
auto& frame = frames[i];
if (!frame.found) {
++remaining;
frame.clear();
}
}
if (remaining == 0) { // we're done
return;
}
int fd = openNoInt("/proc/self/maps", O_RDONLY);
if (fd == -1) {
return;
}
char buf[PATH_MAX + 100]; // Long enough for any line
LineReader reader(fd, buf, sizeof(buf));
while (remaining != 0) {
StringPiece line;
if (reader.readLine(line) != LineReader::kReading) {
break;
}
// Parse line
uintptr_t from;
uintptr_t to;
StringPiece fileName;
if (!parseProcMapsLine(line, from, to, fileName)) {
continue;
}
bool first = true;
std::shared_ptr<ElfFile> elfFile;
// See if any addresses are here
for (size_t i = 0; i < addressCount; ++i) {
auto& frame = frames[i];
if (frame.found) {
continue;
}
uintptr_t address = addresses[i];
if (from > address || address >= to) {
continue;
}
// Found
frame.found = true;
--remaining;
// Open the file on first use
if (first) {
first = false;
elfFile = cache_->getFile(fileName);
}
if (!elfFile) {
continue;
}
// Undo relocation
frame.set(elfFile, address - from);
}
}
closeNoInt(fd);
}
void Symbolizer::symbolize(const uintptr_t* addresses,
SymbolizedFrame* frames,
size_t addressCount) {
size_t remaining = 0;
for (size_t i = 0; i < addressCount; ++i) {
auto& frame = frames[i];
if (!frame.found) {
++remaining;
frame.name.clear();
frame.location = Dwarf::LocationInfo();
}
}
if (remaining == 0) { // we're done
return;
}
int fd = openNoInt("/proc/self/maps", O_RDONLY);
if (fd == -1) {
return;
}
char buf[PATH_MAX + 100]; // Long enough for any line
LineReader reader(fd, buf, sizeof(buf));
char fileNameBuf[PATH_MAX];
while (remaining != 0) {
StringPiece line;
if (reader.readLine(line) != LineReader::kReading) {
break;
}
// Parse line
uintptr_t from;
uintptr_t to;
StringPiece fileName;
if (!parseProcMapsLine(line, from, to, fileName)) {
continue;
}
bool first = true;
ElfFile* elfFile = nullptr;
// See if any addresses are here
for (size_t i = 0; i < addressCount; ++i) {
auto& frame = frames[i];
if (frame.found) {
continue;
}
uintptr_t address = addresses[i];
if (from > address || address >= to) {
continue;
}
// Found
frame.found = true;
--remaining;
// Open the file on first use
if (first) {
first = false;
if (fileCount_ < kMaxFiles &&
!fileName.empty() &&
fileName.size() < sizeof(fileNameBuf)) {
memcpy(fileNameBuf, fileName.data(), fileName.size());
fileNameBuf[fileName.size()] = '\0';
auto& f = files_[fileCount_++];
if (f.openNoThrow(fileNameBuf) != -1) {
elfFile = &f;
}
}
}
if (!elfFile) {
continue;
}
// Undo relocation
uintptr_t fileAddress = address - from + elfFile->getBaseAddress();
auto sym = elfFile->getDefinitionByAddress(fileAddress);
if (!sym.first) {
continue;
}
auto name = elfFile->getSymbolName(sym);
if (name) {
frame.name = name;
}
Dwarf(elfFile).findAddress(fileAddress, frame.location);
}
}
closeNoInt(fd);
}