Add stacktrace generation to maxbase

The stacktrace generation is now a part of the maxbase library. The code
is the same code that was previously defined in gateway.cc as a part of
MaxScale.

maxutils/CMakeLists.txt

@@ -1,4 +1,21 @@
 project(maxutils)
 cmake_minimum_required(VERSION 2.8)
 set(CMAKE_CXX_FLAGS "-fPIC -std=c++11 -ggdb -Wall -Werror -Wno-unused-function")
+
+# Check for GLIBC. The XSI version of strerror_r return an int and the GNU version a
+# char*. Depending on this check, we make assumptions about the system.
+include(CheckCXXSourceCompiles)
+check_cxx_source_compiles("
+  #define _GNU_SOURCE 1
+  #include <string.h>\n
+  int main(){\n
+      char errbuf[200];\n
+      return strerror_r(13, errbuf, sizeof(errbuf)) == errbuf;\n
+  }\n"
+  HAVE_GLIBC)
+
+if(HAVE_GLIBC)
+  add_definitions(-DHAVE_GLIBC=1)
+endif()
+
 add_subdirectory(maxbase)

maxutils/maxbase/include/maxbase/stacktrace.hh

@@ -0,0 +1,32 @@
+#pragma once
+/*
+ * Copyright (c) 2018 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2020-01-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+#include <maxbase/ccdefs.hh>
+#include <unistd.h>
+#include <cstring>
+
+namespace maxbase
+{
+
+static inline void default_stacktrace_handler(const char* symbol, const char* command)
+{
+    write(STDOUT_FILENO, symbol, strlen(symbol));
+    write(STDOUT_FILENO, ": ", 2);
+    write(STDOUT_FILENO, command, strlen(command));
+    write(STDOUT_FILENO, "\n", 1);
+}
+
+void dump_stacktrace(void (*handler)(const char* symbol, const char* command) = default_stacktrace_handler);
+
+}

maxutils/maxbase/src/CMakeLists.txt

@@ -1,3 +1,3 @@
-add_library(maxbase STATIC eventcount.cc stopwatch.cc)
+add_library(maxbase STATIC eventcount.cc stopwatch.cc stacktrace.cc)
 set_target_properties(maxbase PROPERTIES VERSION "1.0.0" LINK_FLAGS -Wl,-z,defs)
 install(TARGETS maxbase DESTINATION lib)

maxutils/maxbase/src/stacktrace.cc

@@ -0,0 +1,154 @@
+/*
+ * Copyright (c) 2018 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2020-01-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+#include <maxbase/stacktrace.hh>
+#include <cstdlib>
+#include <cstring>
+#include <cstdio>
+
+#ifdef HAVE_GLIBC
+#include <execinfo.h>
+#include <limits.h>
+#include <stdarg.h>
+
+namespace
+{
+
+static void get_command_output(char* output, size_t size, const char* format, ...)
+{
+    va_list valist;
+    va_start(valist, format);
+    int cmd_len = vsnprintf(NULL, 0, format, valist);
+    va_end(valist);
+
+    va_start(valist, format);
+    char cmd[cmd_len + 1];
+    vsnprintf(cmd, cmd_len + 1, format, valist);
+    va_end(valist);
+
+    *output = '\0';
+    FILE* file = popen(cmd, "r");
+
+    if (file)
+    {
+        size_t nread = fread(output, 1, size, file);
+        nread = nread < size ? nread : size - 1;
+        output[nread--] = '\0';
+
+        // Trim trailing newlines
+        while (output + nread > output && output[nread] == '\n')
+        {
+            output[nread--] = '\0';
+        }
+
+        pclose(file);
+    }
+}
+
+static void extract_file_and_line(const char* symbols, char* cmd, size_t size)
+{
+    const char* filename_end = strchr(symbols, '(');
+    const char* symname_end = strchr(symbols, ')');
+
+    if (filename_end && symname_end)
+    {
+        // This appears to be a symbol in a library
+        char filename[PATH_MAX + 1];
+        char symname[512];
+        char offset[512];
+        snprintf(filename, sizeof(filename), "%.*s", (int)(filename_end - symbols), symbols);
+
+        const char* symname_start = filename_end + 1;
+
+        if (*symname_start != '+')
+        {
+            // We have a string form symbol name and an offset, we need to
+            // extract the symbol address
+
+            const char* addr_offset = symname_start;
+
+            while (addr_offset < symname_end && *addr_offset != '+')
+            {
+                addr_offset++;
+            }
+
+            snprintf(symname, sizeof(symname), "%.*s", (int)(addr_offset - symname_start), symname_start);
+
+            if (addr_offset < symname_end && *addr_offset == '+')
+            {
+                addr_offset++;
+            }
+
+            snprintf(offset, sizeof(offset), "%.*s", (int)(symname_end - addr_offset), addr_offset);
+
+            // Get the hexadecimal address of the symbol
+            get_command_output(cmd, size,
+                               "nm %s |grep ' %s$'|sed -e 's/ .*//' -e 's/^/0x/'",
+                               filename, symname);
+            long long symaddr = strtoll(cmd, NULL, 16);
+            long long offsetaddr = strtoll(offset, NULL, 16);
+
+            // Calculate the file and line now that we have the raw offset into
+            // the library
+            get_command_output(cmd, size,
+                               "addr2line -e %s 0x%x",
+                               filename, symaddr + offsetaddr);
+        }
+        else
+        {
+            // Raw offset into library
+            symname_start++;
+            snprintf(symname, sizeof(symname), "%.*s", (int)(symname_end - symname_start), symname_start);
+            get_command_output(cmd, size, "addr2line -e %s %s", filename, symname);
+        }
+    }
+}
+
+}
+
+namespace maxbase
+{
+
+void dump_stacktrace(void (*handler)(const char* symbol, const char* command))
+{
+    void *addrs[128];
+    int count = backtrace(addrs, 128);
+    char** symbols = backtrace_symbols(addrs, count);
+
+    if (symbols)
+    {
+        for (int n = 0; n < count; n++)
+        {
+            char cmd[PATH_MAX + 1024] = "<not found>";
+            extract_file_and_line(symbols[n], cmd, sizeof(cmd));
+            handler(symbols[n], cmd);
+        }
+        free(symbols);
+    }
+}
+
+}
+
+#else
+
+namespace maxbase
+{
+
+void dump_stacktrace(void (*handler)(const char*, const char*))
+{
+    // We can't dump stacktraces on non-GLIBC systems
+}
+
+}
+
+#endif