SERVER-7080 Add code to emulate backtrace()

backtrace() fills a buffer provided by the caller with addresses
constituting a stack trace.  This emulation allows the display of
addresses in Solaris 10, which can be used with addr2line to see
code locations.

1 files changed, 42 insertions, 0 deletions

diff --git a/src/mongo/platform/backtrace.cpp b/src/mongo/platform/backtrace.cpp
index 9bb3fd0283c..64d593d0157 100644
--- a/src/mongo/platform/backtrace.cpp
+++ b/src/mongo/platform/backtrace.cpp
@@ -19,6 +19,7 @@
 #include "mongo/platform/backtrace.h"
 
 #include <dlfcn.h>
+#include <ucontext.h>
 
 #include "mongo/base/init.h"
 #include "mongo/base/status.h"
@@ -26,7 +27,48 @@
 namespace mongo {
 namespace pal {
 
+namespace {
+    class WalkcontextCallback {
+    public:
+        WalkcontextCallback(uintptr_t* array, int size)
+            : _position(0),
+              _count(size),
+              _addresses(array) {}
+
+        // This callback function is called from C code, and so must not throw exceptions
+        //
+        static int callbackFunction(uintptr_t address,
+                                    int signalNumber,
+                                    WalkcontextCallback* thisContext) {
+            if (thisContext->_position < thisContext->_count) {
+                thisContext->_addresses[thisContext->_position++] = address;
+                return 0;
+            }
+            return 1;
+        }
+        int getCount() const { return static_cast<int>(_position); }
+    private:
+        size_t _position;
+        size_t _count;
+        uintptr_t* _addresses;
+    };
+} // namespace
+
+    typedef int (*WalkcontextCallbackFunc)(uintptr_t address, int signalNumber, void* thisContext);
+
     int backtrace_emulation(void** array, int size) {
+        WalkcontextCallback walkcontextCallback(reinterpret_cast<uintptr_t*>(array), size);
+        ucontext_t context;
+        if (getcontext(&context) != 0) {
+            return 0;
+        }
+        int wcReturn = walkcontext(
+                &context,
+                reinterpret_cast<WalkcontextCallbackFunc>(WalkcontextCallback::callbackFunction),
+                static_cast<void*>(&walkcontextCallback));
+        if (wcReturn == 0) {
+            return walkcontextCallback.getCount();
+        }
         return 0;
     }