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-rw-r--r--src/mongo/util/stacktrace_posix.cpp302
1 files changed, 204 insertions, 98 deletions
diff --git a/src/mongo/util/stacktrace_posix.cpp b/src/mongo/util/stacktrace_posix.cpp
index 7a63e6c26f0..c354a2d787a 100644
--- a/src/mongo/util/stacktrace_posix.cpp
+++ b/src/mongo/util/stacktrace_posix.cpp
@@ -48,6 +48,7 @@
#include "mongo/platform/compiler_gcc.h"
#include "mongo/util/log.h"
#include "mongo/util/scopeguard.h"
+#include "mongo/util/stacktrace_json.h"
#include "mongo/util/version.h"
#define MONGO_STACKTRACE_BACKEND_LIBUNWIND 1
@@ -70,16 +71,33 @@
namespace mongo {
namespace stacktrace_detail {
+namespace {
constexpr int kFrameMax = 100;
constexpr size_t kSymbolMax = 512;
constexpr StringData kUnknownFileName = "???"_sd;
+class OstreamJsonSink : public StackTraceSink {
+public:
+ explicit OstreamJsonSink(std::ostream& os) : _os(os) {}
+
+private:
+ void doWrite(StringData v) override {
+ _os << v;
+ }
+ void doWrite(uint64_t v) override {
+ _os << v;
+ }
+ std::ostream& _os;
+};
+
struct StackTraceOptions {
bool withProcessInfo = true;
bool withHumanReadable = true;
+ bool trimSoMap = true; // only include the somap entries relevant to the backtrace
};
+
// E.g., for "/foo/bar/my.txt", returns "my.txt".
StringData getBaseName(StringData path) {
size_t lastSlash = path.rfind('/');
@@ -116,19 +134,163 @@ public:
virtual void advance() = 0;
};
-template <typename T>
-struct Quoted {
- explicit Quoted(const T& v) : v(v) {}
+// World's dumbest "vector". Doesn't allocate.
+template <typename T, size_t N>
+struct ArrayAndSize {
+ using iterator = typename std::array<T, N>::iterator;
+ using reference = typename std::array<T, N>::reference;
+ using const_reference = typename std::array<T, N>::const_reference;
- friend std::ostream& operator<<(std::ostream& os, const Quoted& q) {
- return os << "\"" << q.v << "\"";
+ auto begin() {
+ return _arr.begin();
+ }
+ auto end() {
+ return _arr.begin() + _n;
+ }
+ reference operator[](size_t i) {
+ return _arr[i];
}
- const T& v;
+ auto begin() const {
+ return _arr.begin();
+ }
+ auto end() const {
+ return _arr.begin() + _n;
+ }
+ const_reference operator[](size_t i) const {
+ return _arr[i];
+ }
+
+ void push_back(const T& v) {
+ _arr[_n++] = v;
+ }
+
+ std::array<T, N> _arr;
+ size_t _n = 0;
};
/**
- * Prints a stack backtrace for the current thread to the specified ostream.
+ * Iterates through the stacktrace to extract the bases addresses for each address in the
+ * stacktrace. Returns a sorted, unique sequence of these base addresses.
+ */
+ArrayAndSize<uint64_t, kFrameMax> uniqueBases(IterationIface& source) {
+ ArrayAndSize<uint64_t, kFrameMax> bases;
+ for (source.start(source.kSymbolic); !source.done(); source.advance()) {
+ const auto& f = source.deref();
+ if (f.soFile) {
+ uintptr_t base = f.soFile->base;
+ // Push base into bases keeping it sorted and unique.
+ auto ins = std::lower_bound(bases.begin(), bases.end(), base);
+ if (ins != bases.end() && *ins == base) {
+ continue;
+ } else {
+ bases.push_back(base);
+ std::rotate(ins, bases.end() - 1, bases.end());
+ }
+ }
+ }
+ return bases;
+}
+
+void printRawAddrsLine(IterationIface& source,
+ StackTraceSink& sink,
+ const StackTraceOptions& options) {
+ for (source.start(source.kRaw); !source.done(); source.advance()) {
+ sink << " " << Hex(source.deref().address).str();
+ }
+}
+
+void appendJsonBacktrace(IterationIface& source,
+ CheapJson::Value& jsonRoot,
+ const StackTraceOptions& options) {
+ CheapJson::Value frames = jsonRoot.appendKey("backtrace").appendArr();
+ for (source.start(source.kSymbolic); !source.done(); source.advance()) {
+ const auto& f = source.deref();
+ uint64_t base = f.soFile ? f.soFile->base : 0;
+ CheapJson::Value frameObj = frames.appendObj();
+ frameObj.appendKey("b").append(Hex(base).str());
+ frameObj.appendKey("o").append(Hex(f.address - base).str());
+ if (f.symbol) {
+ frameObj.appendKey("s").append(f.symbol->name);
+ }
+ }
+}
+
+/**
+ * Most elements of `bsonProcInfo` are copied verbatim into the `jsonProcInfo` Json
+ * object. But if `bases` is non-null, The "somap" BSON Array is filtered to only
+ * include elements corresponding to the addresses in `bases`.
+ */
+void printJsonProcessInfoCommon(const BSONObj& bsonProcInfo,
+ CheapJson::Value& jsonProcInfo,
+ const ArrayAndSize<uint64_t, kFrameMax>* bases) {
+ for (const BSONElement& be : bsonProcInfo) {
+ if (bases && be.type() == BSONType::Array) {
+ if (StringData key = be.fieldNameStringData(); key == "somap") {
+ CheapJson::Value jsonArr = jsonProcInfo.appendKey(key).appendArr();
+ for (const BSONElement& ae : be.Array()) {
+ BSONObj bRec = ae.embeddedObject();
+ uint64_t soBase = Hex::fromHex(bRec.getStringField("b"));
+ if (std::binary_search(bases->begin(), bases->end(), soBase))
+ jsonArr.append(ae);
+ }
+ continue;
+ }
+ }
+ jsonProcInfo.append(be);
+ }
+}
+
+void printJsonProcessInfoTrimmed(IterationIface& source,
+ const BSONObj& bsonProcInfo,
+ CheapJson::Value& jsonProcInfo) {
+ auto bases = uniqueBases(source);
+ printJsonProcessInfoCommon(bsonProcInfo, jsonProcInfo, &bases);
+}
+
+void appendJsonProcessInfo(IterationIface& source,
+ CheapJson::Value& jsonRoot,
+ const StackTraceOptions& options) {
+ if (!options.withProcessInfo)
+ return;
+ auto bsonSoMap = globalSharedObjectMapInfo();
+ if (!bsonSoMap)
+ return;
+ const BSONObj& bsonProcInfo = bsonSoMap->obj();
+ CheapJson::Value jsonProcInfo = jsonRoot.appendKey("processInfo").appendObj();
+ if (options.trimSoMap) {
+ printJsonProcessInfoTrimmed(source, bsonProcInfo, jsonProcInfo);
+ } else {
+ printJsonProcessInfoCommon(bsonProcInfo, jsonProcInfo, nullptr);
+ }
+}
+
+void printHumanReadable(IterationIface& source,
+ StackTraceSink& sink,
+ const StackTraceOptions& options) {
+ for (source.start(source.kSymbolic); !source.done(); source.advance()) {
+ const auto& f = source.deref();
+ sink << " ";
+ if (f.soFile) {
+ sink << getBaseName(f.soFile->name);
+ sink << "(";
+ if (f.symbol) {
+ sink << f.symbol->name << "+0x" << Hex(f.address - f.symbol->base).str();
+ } else {
+ // No symbol, so fall back to the `soFile` offset.
+ sink << "+0x" << Hex(f.address - f.soFile->base).str();
+ }
+ sink << ")";
+ } else {
+ // Not even shared object information, just punt with unknown filename (SERVER-43551)
+ sink << kUnknownFileName;
+ }
+ sink << " [0x" << Hex(f.address).str() << "]\n";
+ }
+}
+
+/**
+ * Prints a stack backtrace for the current thread to the specified sink.
*
* The format of the backtrace is:
*
@@ -148,83 +310,23 @@ struct Quoted {
* the objects referenced in the "b" fields of the "backtrace" list.
*/
void printStackTraceGeneric(IterationIface& source,
- std::ostream& os,
+ StackTraceSink& sink,
const StackTraceOptions& options) {
- // TODO: make this signal-safe.
- os << std::hex << std::uppercase;
- auto sg = makeGuard([&] { os << std::dec << std::nouppercase; });
- // First, just the raw backtrace addresses.
- for (source.start(source.kRaw); !source.done(); source.advance()) {
- const auto& f = source.deref();
- os << ' ' << f.address;
- }
-
- os << "\n----- BEGIN BACKTRACE -----\n";
-
- // Display the JSON backtrace
+ // TODO(SERVER-42670): make this asynchronous signal safe.
+ printRawAddrsLine(source, sink, options);
+ sink << "\n----- BEGIN BACKTRACE -----\n";
{
- os << "{";
- os << Quoted("backtrace") << ":";
- {
- os << "[";
- StringData frameComma;
- for (source.start(source.kSymbolic); !source.done(); source.advance()) {
- const auto& f = source.deref();
- os << frameComma;
- frameComma = ","_sd;
- {
- os << "{";
- StringData fieldSep = "";
- auto addField = [&](StringData k, auto&& v) {
- os << fieldSep << Quoted(k) << ":" << Quoted(v);
- fieldSep = ","_sd;
- };
- if (f.soFile) {
- // Cast because integers obey `uppercase` and pointers don't.
- addField("b", f.soFile->base);
- addField("o", (f.address - f.soFile->base));
- if (f.symbol) {
- addField("s", f.symbol->name);
- }
- } else {
- addField("b", uintptr_t{0});
- addField("o", f.address);
- }
- os << "}";
- }
- }
- os << "]";
- }
- if (options.withProcessInfo) {
- if (auto soMap = globalSharedObjectMapInfo())
- os << "," << Quoted("processInfo") << ":" << soMap->json();
- }
- os << "}";
+ CheapJson json{sink};
+ CheapJson::Value doc = json.doc();
+ CheapJson::Value jsonRootObj = doc.appendObj();
+ appendJsonBacktrace(source, jsonRootObj, options);
+ appendJsonProcessInfo(source, jsonRootObj, options);
}
- os << "\n";
- // Display the human-readable trace
+ sink << "\n";
if (options.withHumanReadable) {
- for (source.start(source.kSymbolic); !source.done(); source.advance()) {
- const auto& f = source.deref();
- os << " ";
- if (f.soFile) {
- os << getBaseName(f.soFile->name);
- os << "(";
- if (f.symbol) {
- os << f.symbol->name << "+0x" << (f.address - f.symbol->base);
- } else {
- // No symbol, so fall back to the `soFile` offset.
- os << "+0x" << (f.address - f.soFile->base);
- }
- os << ")";
- } else {
- // Not even shared object information, just punt with unknown filename.
- os << kUnknownFileName;
- }
- os << " [0x" << f.address << "]\n";
- }
+ printHumanReadable(source, sink, options);
}
- os << "----- END BACKTRACE -----\n";
+ sink << "----- END BACKTRACE -----\n";
}
void mergeDlInfo(AddressMetadata& f) {
@@ -252,7 +354,8 @@ void mergeDlInfo(AddressMetadata& f) {
class Iteration : public IterationIface {
public:
- explicit Iteration(std::ostream& os, bool fromSignal) : _os(os), _fromSignal(fromSignal) {
+ explicit Iteration(StackTraceSink& sink, bool fromSignal)
+ : _sink(sink), _fromSignal(fromSignal) {
if (int r = unw_getcontext(&_context); r < 0) {
_os << "unw_getcontext: " << unw_strerror(r) << std::endl;
_failed = true;
@@ -270,7 +373,7 @@ private:
}
int r = unw_init_local2(&_cursor, &_context, _fromSignal ? UNW_INIT_SIGNAL_FRAME : 0);
if (r < 0) {
- _os << "unw_init_local2: " << unw_strerror(r) << std::endl;
+ _sink << "unw_init_local2: " << unw_strerror(r) << "\n";
_end = true;
return;
}
@@ -289,7 +392,7 @@ private:
int r = unw_step(&_cursor);
if (r <= 0) {
if (r < 0) {
- _os << "error: unw_step: " << unw_strerror(r) << std::endl;
+ _sink << "error: unw_step: " << unw_strerror(r) << "\n";
}
_end = true;
}
@@ -302,7 +405,7 @@ private:
_f = {};
unw_word_t pc;
if (int r = unw_get_reg(&_cursor, UNW_REG_IP, &pc); r < 0) {
- _os << "unw_get_reg: " << unw_strerror(r) << std::endl;
+ _sink << "unw_get_reg: " << unw_strerror(r) << "\n";
_end = true;
return;
}
@@ -315,7 +418,7 @@ private:
unw_word_t offset;
if (int r = unw_get_proc_name(&_cursor, _symbolBuf, sizeof(_symbolBuf), &offset);
r < 0) {
- _os << "unw_get_proc_name(" << _f.address << "): " << unw_strerror(r) << std::endl;
+ _sink << "unw_get_proc_name(" << _f.address << "): " << unw_strerror(r) << "\n";
} else {
_f.symbol = NameBase{_symbolBuf, _f.address - offset};
}
@@ -323,7 +426,7 @@ private:
}
}
- std::ostream& _os;
+ StackTraceSink& _sink;
bool _fromSignal;
Flags _flags;
@@ -339,21 +442,21 @@ private:
};
MONGO_COMPILER_NOINLINE
-void printStackTrace(std::ostream& os, bool fromSignal) {
- Iteration iteration(os, fromSignal);
- printStackTraceGeneric(iteration, os, StackTraceOptions{});
+void printStackTrace(StackTraceSink& sink, bool fromSignal) {
+ Iteration iteration(sink, fromSignal);
+ printStackTraceGeneric(iteration, sink, StackTraceOptions{});
}
#elif MONGO_STACKTRACE_BACKEND == MONGO_STACKTRACE_BACKEND_EXECINFO
class Iteration : public IterationIface {
public:
- explicit Iteration(std::ostream& os, bool fromSignal) {
+ explicit Iteration(StackTraceSink& sink, bool fromSignal) {
_n = ::backtrace(_addresses.data(), _addresses.size());
if (_n == 0) {
int err = errno;
- os << "Unable to collect backtrace addresses (errno: " << err << ' ' << strerror(err)
- << ')' << std::endl;
+ sink << "Unable to collect backtrace addresses (errno: " << err << " " << strerror(err)
+ << ")\n";
return;
}
}
@@ -394,30 +497,33 @@ private:
};
MONGO_COMPILER_NOINLINE
-void printStackTrace(std::ostream& os, bool fromSignal) {
- Iteration iteration(os, fromSignal);
- printStackTraceGeneric(iteration, os, StackTraceOptions{});
+void printStackTrace(StackTraceSink& sink, bool fromSignal) {
+ Iteration iteration(sink, fromSignal);
+ printStackTraceGeneric(iteration, sink, StackTraceOptions{});
}
#elif MONGO_STACKTRACE_BACKEND == MONGO_STACKTRACE_BACKEND_NONE
MONGO_COMPILER_NOINLINE
-void printStackTrace(std::ostream& os, bool fromSignal) {
- os << "This platform does not support printing stacktraces" << std::endl;
+void printStackTrace(StackTraceSink& sink, bool fromSignal) {
+ sink << "This platform does not support printing stacktraces\n";
}
#endif // MONGO_STACKTRACE_BACKEND
+} // namespace
} // namespace stacktrace_detail
MONGO_COMPILER_NOINLINE
void printStackTrace(std::ostream& os) {
- stacktrace_detail::printStackTrace(os, false);
+ stacktrace_detail::OstreamJsonSink sink{os};
+ stacktrace_detail::printStackTrace(sink, false);
}
MONGO_COMPILER_NOINLINE
void printStackTraceFromSignal(std::ostream& os) {
- stacktrace_detail::printStackTrace(os, true);
+ stacktrace_detail::OstreamJsonSink sink{os};
+ stacktrace_detail::printStackTrace(sink, true);
}
} // namespace mongo
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