Print stack trace on exceptions

if libunwind is found.

Useful for debugging logs.

1 files changed, 120 insertions, 0 deletions

diff --git a/src/common/stack_trace.cpp b/src/common/stack_trace.cpp
new file mode 100644
index 000000000..1a65ca656
--- /dev/null
+++ b/src/common/stack_trace.cpp
@@ -0,0 +1,120 @@
+// Copyright (c) 2016, The Monero Project
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "common/stack_trace.h"
+#include "misc_log_ex.h"
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+#include <cxxabi.h>
+#include <dlfcn.h>
+
+// from http://stackoverflow.com/questions/11665829/how-can-i-print-stack-trace-for-caught-exceptions-in-c-code-injection-in-c
+#ifdef STATICLIB
+#define CXA_THROW __wrap___cxa_throw
+extern "C" void __real___cxa_throw(void *ex, void *info, void (*dest)(void*));
+#else
+#define CXA_THROW __cxa_throw
+#endif
+
+extern "C" void CXA_THROW(void *ex, void *info, void (*dest)(void*))
+{
+
+  int status;
+  char *dsym = abi::__cxa_demangle(((const std::type_info*)info)->name(), NULL, NULL, &status);
+  tools::log_stack_trace((std::string("Exception: ")+((!status && dsym) ? dsym : (const char*)info)).c_str());
+  free(dsym);
+
+#ifdef STATICLIB
+  __real___cxa_throw(ex, info, dest);
+#else
+  static void (*const rethrow)(void*, void*, void(*)(void*)) __attribute__((noreturn)) = (void(*)(void*, void*, void(*)(void*)))dlsym(RTLD_NEXT, "__cxa_throw");
+  rethrow(ex, info, dest);
+#endif
+}
+
+namespace
+{
+  std::string stack_trace_log;
+}
+
+namespace tools
+{
+
+void set_stack_trace_log(const std::string &log)
+{
+  stack_trace_log = log;
+}
+
+void log_stack_trace(const char *msg)
+{
+#ifdef HAVE_LIBUNWIND
+  unw_context_t ctx;
+  unw_cursor_t cur;
+  unw_word_t ip, off;
+  unsigned level;
+  char sym[512], *dsym;
+  int status;
+  const char *log = stack_trace_log.empty() ? NULL : stack_trace_log.c_str();
+
+  if (msg)
+    LOG_PRINT2(log, msg, LOG_LEVEL_0);
+  LOG_PRINT2(log, "Unwinded call stack:", LOG_LEVEL_0);
+  if (unw_getcontext(&ctx) < 0) {
+    LOG_PRINT2(log, "Failed to create unwind context", LOG_LEVEL_0);
+    return;
+  }
+  if (unw_init_local(&cur, &ctx) < 0) {
+    LOG_PRINT2(log, "Failed to find the first unwind frame", LOG_LEVEL_0);
+    return;
+  }
+  for (level = 1; level < 999; ++level) { // 999 for safety
+    int ret = unw_step(&cur);
+    if (ret < 0) {
+      LOG_PRINT2(log, "Failed to find the next frame", LOG_LEVEL_0);
+      return;
+    }
+    if (ret == 0)
+      break;
+    if (unw_get_reg(&cur, UNW_REG_IP, &ip) < 0) {
+      LOG_PRINT2(log, "  " << std::setw(4) << level, LOG_LEVEL_0);
+      continue;
+    }
+    if (unw_get_proc_name(&cur, sym, sizeof(sym), &off) < 0) {
+      LOG_PRINT2(log, "  " << std::setw(4) << level << std::setbase(16) << std::setw(20) << "0x" << ip, LOG_LEVEL_0);
+      continue;
+    }
+    dsym = abi::__cxa_demangle(sym, NULL, NULL, &status);
+    LOG_PRINT2(log, "  " << std::setw(4) << level << std::setbase(16) << std::setw(20) << "0x" << ip << " " << (!status && dsym ? dsym : sym) << " + " << "0x" << off, LOG_LEVEL_0);
+    free(dsym);
+  }
+#else
+#warning libunwind disabled, no stack traces
+#endif
+}
+
+}  // namespace tools