From d9831ae5329d6916667ee9beb885c3e4c35c4018 Mon Sep 17 00:00:00 2001
From: unknown <davi@mysql.com/endora.local>
Date: Thu, 7 Feb 2008 19:58:06 -0200
Subject: Bug#31891 Meaningful stack trace

On crashes generate a user-friendly resolved and demangled stack
trace when libc provides the necessary functions (newer libc on i386,
x86_64, powerpc, ia64, alpha and s390). Otherwise print a numeric
stack trace as before, relying on resolve_stack_dump utility.


configure.in:
  Add check for backtrace headers, backtrace functions and if
  __cxa_demangle (libstdc++) is available at link time.
sql/mysqld.cc:
  Print the value of the THD::killed variable when dumping. In
  some circumstances knowing if the thread was killed makes
  debugging easier.
sql/stacktrace.c:
  Use the glibc backtrace function when available and demangle
  C++ function names if the __cxa_demangle function is available.
sql/stacktrace.h:
  Locally export and wrap in C linkage the C++ function __cxa_demangle
  if available.
---
 sql/stacktrace.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)

(limited to 'sql/stacktrace.c')

diff --git a/sql/stacktrace.c b/sql/stacktrace.c
index b1267e20774..3d718dfd9d2 100644
--- a/sql/stacktrace.c
+++ b/sql/stacktrace.c
@@ -17,11 +17,16 @@
 #include "stacktrace.h"
 #include <signal.h>
 #include <my_pthread.h>
+#include <m_string.h>
 
 #ifdef HAVE_STACKTRACE
 #include <unistd.h>
 #include <strings.h>
 
+#if HAVE_EXECINFO_H
+#include <execinfo.h>
+#endif
+
 #define PTR_SANE(p) ((p) && (char*)(p) >= heap_start && (char*)(p) <= heap_end)
 
 char *heap_start;
@@ -93,9 +98,68 @@ inline uint32* find_prev_pc(uint32* pc, uchar** fp)
 }
 #endif /* defined(__alpha__) && defined(__GNUC__) */
 
+#if BACKTRACE_DEMANGLE
+static void my_demangle_symbols(char **addrs, int n)
+{
+  int status, i;
+  char *begin, *end, *demangled;
+
+  for (i= 0; i < n; i++)
+  {
+    demangled= NULL;
+    begin= strchr(addrs[i], '(');
+    end= begin ? strchr(begin, '+') : NULL;
+
+    if (begin && end)
+    {
+      *begin++= *end++= '\0';
+      demangled= my_demangle(begin, &status);
+      if (!demangled || status)
+      {
+        demangled= NULL;
+        begin[-1]= '(';
+        end[-1]= '+';
+      }
+    }
+
+    if (demangled)
+      fprintf(stderr, "%s(%s+%s\n", addrs[i], demangled, end);
+    else
+      fprintf(stderr, "%s\n", addrs[i]);
+  }
+}
+#endif
+
+
+#if HAVE_BACKTRACE
+static void backtrace_current_thread(void)
+{
+  void *addrs[128];
+  char **strings= NULL;
+  int n = backtrace(addrs, array_elements(addrs));
+#if BACKTRACE_DEMANGLE
+  if ((strings= backtrace_symbols(addrs, n)))
+  {
+    my_demangle_symbols(strings, n);
+    free(strings);
+  }
+#endif
+#if HAVE_BACKTRACE_SYMBOLS_FD
+  if (!strings)
+  {
+    backtrace_symbols_fd(addrs, n, fileno(stderr));
+  }
+#endif
+}
+#endif
+
 
 void  print_stacktrace(uchar* stack_bottom, ulong thread_stack)
 {
+#if HAVE_BACKTRACE
+  backtrace_current_thread();
+  return;
+#endif
   uchar** fp;
   uint frame_count = 0, sigreturn_frame_count;
 #if defined(__alpha__) && defined(__GNUC__)
-- 
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