MDEV-14315 -- Reflect use of tcmalloc in a system variable and error log

  * The version of tcmalloc is written to the system variable
    'version_malloc_library' if tcmalloc is used, similarly to
    jemalloc
  * Extracted method guess_malloc_library()

2 files changed, 65 insertions, 1 deletions

diff --git a/mysys/CMakeLists.txt b/mysys/CMakeLists.txt
index b9f92124cc3..8e4882328f5 100644
--- a/mysys/CMakeLists.txt
+++ b/mysys/CMakeLists.txt
@@ -36,7 +36,8 @@ SET(MYSYS_SOURCES  array.c charset-def.c charset.c checksum.c my_default.c
 				string.c thr_alarm.c thr_lock.c thr_mutex.c
 				thr_rwlock.c thr_timer.c
                                 tree.c typelib.c base64.c my_memmem.c
-                                 my_getpagesize.c
+                                my_getpagesize.c
+                                guess_malloc_library.c
 				lf_alloc-pin.c lf_dynarray.c lf_hash.c
                                 safemalloc.c my_new.cc
 				my_atomic.c my_getncpus.c my_safehash.c my_chmod.c my_rnd.c
diff --git a/mysys/guess_malloc_library.c b/mysys/guess_malloc_library.c
new file mode 100644
index 00000000000..2e640757e11
--- /dev/null
+++ b/mysys/guess_malloc_library.c
@@ -0,0 +1,63 @@
+/* Copyright (c) 2002, 2015, Oracle and/or its affiliates.
+   Copyright (c) 2012, 2017, MariaDB Corporation.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
+
+/* guess_malloc_library() deduces, to the best of its ability,
+   the currently used malloc library and its version */
+
+#include <stddef.h>
+#include <m_string.h>
+
+char *guess_malloc_library()
+{
+#ifndef HAVE_DLOPEN
+  return (char*) MALLOC_LIBRARY;
+#else
+  static char buf[128];
+
+  if (strcmp(MALLOC_LIBRARY, "system") != 0)
+  {
+    return (char*) MALLOC_LIBRARY;
+  }
+
+  /* tcmalloc */
+  typedef const char* (*tc_version_type)(int*, int*, const char**);
+  tc_version_type tc_version_func =
+    (tc_version_type) dlsym(RTLD_DEFAULT, "tc_version");
+  if (tc_version_func)
+  {
+    int major, minor;
+    const char* ver_str = tc_version_func(&major, &minor, NULL);
+    strxnmov(buf, sizeof(buf)-1, "tcmalloc ", ver_str, NULL);
+    return buf;
+  }
+
+  /* jemalloc */
+  typedef int (*mallctl_type)(const char*, void*, size_t*, void*, size_t);
+  mallctl_type mallctl_func =
+    (mallctl_type) dlsym(RTLD_DEFAULT, "mallctl");
+  if (mallctl_func)
+  {
+    char *ver;
+    size_t len = sizeof(ver);
+    mallctl_func("version", &ver, &len, NULL, 0);
+    strxnmov(buf, sizeof(buf)-1, "jemalloc ", ver, NULL);
+    return buf;
+  }
+
+  return (char*) MALLOC_LIBRARY;
+#endif
+}
+