BUG#24566529: BACKPORT BUG#23575445 TO 5.6

Stack traces were not printed by our signal handler on FreeBSD
since we didn't find backtrace(). However, since FreeBSD 10.0
backtrace() is available, but it requires the execinfo library.

This patch fixes the problem by adding -lexecinfo when
doing CMake configure checks and when linking the server
(if execinfo exists). Note that the number of stack frames
returned by backtrace() seems very limited - at least on
FreeBSD 10.2.

Also, the PTR_SANE macro which tries to check if a pointer
is invalid (used when printing pointer values in stack traces)
gave false negatives on OSX/FreeBSD. On these platforms we
now simply check if the pointer is non-null. This also removes
a sbrk() deprecation warning when building on OS X. (It was
before only disabled with building using XCode).

cmake/os/WindowsCache.cmake

@@ -34,7 +34,6 @@ SET(HAVE_BACKTRACE_SYMBOLS_FD CACHE  INTERNAL "")
 SET(HAVE_BMOVE CACHE  INTERNAL "")
 SET(HAVE_BSD_SIGNALS CACHE  INTERNAL "")
 SET(HAVE_BSEARCH 1 CACHE  INTERNAL "")
-SET(HAVE_BSS_START CACHE  INTERNAL "")
 SET(HAVE_CHOWN CACHE  INTERNAL "")
 SET(HAVE_CLOCK_GETTIME CACHE  INTERNAL "")
 SET(HAVE_COMPRESS CACHE  INTERNAL "")

config.h.cmake

@@ -290,7 +290,6 @@
 #cmakedefine HAVE_AIO_READ 1
 /* Symbols we may use */
 /* used by stacktrace functions */
-#cmakedefine HAVE_BSS_START 1
 #cmakedefine HAVE_BACKTRACE 1
 #cmakedefine HAVE_BACKTRACE_SYMBOLS 1
 #cmakedefine HAVE_BACKTRACE_SYMBOLS_FD 1

configure.cmake

@@ -289,10 +289,14 @@ IF(UNIX)
   IF(NOT LIBRT)
     MY_SEARCH_LIBS(clock_gettime rt LIBRT)
   ENDIF()
+  MY_SEARCH_LIBS(backtrace execinfo LIBEXECINFO)
+
   FIND_PACKAGE(Threads)
 
   SET(CMAKE_REQUIRED_LIBRARIES 
-    ${LIBM} ${LIBNSL} ${LIBBIND} ${LIBCRYPT} ${LIBSOCKET} ${LIBDL} ${CMAKE_THREAD_LIBS_INIT} ${LIBRT})
+    ${LIBM} ${LIBNSL} ${LIBBIND} ${LIBCRYPT} ${LIBSOCKET} ${LIBDL}
+    ${CMAKE_THREAD_LIBS_INIT} ${LIBRT} ${LIBEXECINFO}
+  )
   # Need explicit pthread for gcc -fsanitize=address
   IF(CMAKE_USE_PTHREADS_INIT AND CMAKE_C_FLAGS MATCHES "-fsanitize=")
     SET(CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES} pthread)
@@ -1077,14 +1081,6 @@ CHECK_CXX_SOURCE_COMPILES("
   HAVE_ABI_CXA_DEMANGLE)
 ENDIF()
 
-CHECK_C_SOURCE_COMPILES("
-  int main(int argc, char **argv) 
-  {
-    extern char *__bss_start;
-    return __bss_start ? 1 : 0;
-  }"
-HAVE_BSS_START)
-
 CHECK_C_SOURCE_COMPILES("
     int main()
     {

mysys/CMakeLists.txt

@@ -1,4 +1,4 @@
-# Copyright (c) 2006, 2015, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2006, 2016, Oracle and/or its affiliates. All rights reserved.
 # 
 # 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
@@ -60,7 +60,7 @@ ENDIF()
 
 ADD_CONVENIENCE_LIBRARY(mysys ${MYSYS_SOURCES})
 TARGET_LINK_LIBRARIES(mysys dbug strings ${ZLIB_LIBRARY} 
- ${LIBNSL} ${LIBM} ${LIBRT})
+ ${LIBNSL} ${LIBM} ${LIBRT} ${LIBEXECINFO})
 DTRACE_INSTRUMENT(mysys)
 
 # Need explicit pthread for gcc -fsanitize=address

mysys/stacktrace.c

@@ -33,19 +33,20 @@
 #include <execinfo.h>
 #endif
 
+#ifdef __linux__
+/* __bss_start doesn't seem to work on FreeBSD and doesn't exist on OSX/Solaris. */
 #define PTR_SANE(p) ((p) && (char*)(p) >= heap_start && (char*)(p) <= heap_end)
-
 static char *heap_start;
-
-#ifdef HAVE_BSS_START
 extern char *__bss_start;
-#endif
+#else
+#define PTR_SANE(p) (p)
+#endif /* __linux */
 
 void my_init_stacktrace()
 {
-#ifdef HAVE_BSS_START
+#ifdef __linux__
   heap_start = (char*) &__bss_start;
-#endif
+#endif /* __linux__ */
 }
 
 #ifdef __linux__
@@ -134,14 +135,15 @@ static int safe_print_str(const char *addr, int max_len)
 
 void my_safe_print_str(const char* val, int max_len)
 {
+#ifdef __linux__
+/* Only needed by the linux version of PTR_SANE */
   char *heap_end;
 
-#ifdef __linux__
   if (!safe_print_str(val, max_len))
     return;
-#endif
 
   heap_end= (char*) sbrk(0);
+#endif
 
   if (!PTR_SANE(val))
   {