release/src/router/mysql/sql/signal_handler.cc

   1 /* Copyright (c) 2011, 2012, Oracle and/or its affiliates. All rights reserved.
   2
   3    This program is free software; you can redistribute it and/or modify
   4    it under the terms of the GNU General Public License as published by
   5    the Free Software Foundation; version 2 of the License.
   6
   7    This program is distributed in the hope that it will be useful,
   8    but WITHOUT ANY WARRANTY; without even the implied warranty of
   9    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10    GNU General Public License for more details.
  11
  12    You should have received a copy of the GNU General Public License
  13    along with this program; if not, write to the Free Software
  14    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA */
  15
  16 #include "my_global.h"
  17 #include <signal.h>
  18
  19 #include "mysql_priv.h"
  20 #include "my_stacktrace.h"
  21
  22 #ifdef __WIN__
  23 #include <crtdbg.h>
  24 #define SIGNAL_FMT "exception 0x%x"
  25 #else
  26 #define SIGNAL_FMT "signal %d"
  27 #endif
  28
  29 /*
  30   We are handling signals in this file.
  31   Any global variables we read should be 'volatile sig_atomic_t'
  32   to guarantee that we read some consistent value.
  33  */
  34 static volatile sig_atomic_t segfaulted= 0;
  35 extern ulong max_used_connections;
  36 extern volatile sig_atomic_t calling_initgroups;
  37 #ifdef HAVE_NPTL
  38 extern volatile sig_atomic_t ld_assume_kernel_is_set;
  39 #endif
  40
  41 /**
  42  * Handler for fatal signals
  43  *
  44  * Fatal events (seg.fault, bus error etc.) will trigger
  45  * this signal handler.  The handler will try to dump relevant
  46  * debugging information to stderr and dump a core image.
  47  *
  48  * Signal handlers can only use a set of 'safe' system calls
  49  * and library functions.  A list of safe calls in POSIX systems
  50  * are available at:
  51  *  http://pubs.opengroup.org/onlinepubs/009695399/functions/xsh_chap02_04.html
  52  * For MS Windows, guidelines are available at:
  53  *  http://msdn.microsoft.com/en-us/library/xdkz3x12(v=vs.71).aspx
  54  *
  55  * @param sig Signal number
  56 */
  57 extern "C" sig_handler handle_fatal_signal(int sig)
  58 {
  59   if (segfaulted)
  60   {
  61     my_safe_printf_stderr("Fatal " SIGNAL_FMT " while backtracing\n", sig);
  62     _exit(1); /* Quit without running destructors */
  63   }
  64
  65   segfaulted = 1;
  66
  67 #ifdef __WIN__
  68   SYSTEMTIME utc_time;
  69   GetSystemTime(&utc_time);
  70   const long hrs=  utc_time.wHour;
  71   const long mins= utc_time.wMinute;
  72   const long secs= utc_time.wSecond;
  73 #else
  74   /* Using time() instead of my_time() to avoid looping */
  75   const time_t curr_time= time(NULL);
  76   /* Calculate time of day */
  77   const long tmins = curr_time / 60;
  78   const long thrs  = tmins / 60;
  79   const long hrs   = thrs  % 24;
  80   const long mins  = tmins % 60;
  81   const long secs  = curr_time % 60;
  82 #endif
  83
  84   char hrs_buf[3]= "00";
  85   char mins_buf[3]= "00";
  86   char secs_buf[3]= "00";
  87   my_safe_itoa(10, hrs, &hrs_buf[2]);
  88   my_safe_itoa(10, mins, &mins_buf[2]);
  89   my_safe_itoa(10, secs, &secs_buf[2]);
  90
  91   my_safe_printf_stderr("%s:%s:%s UTC - mysqld got " SIGNAL_FMT " ;\n",
  92                         hrs_buf, mins_buf, secs_buf, sig);
  93
  94   my_safe_printf_stderr("%s",
  95     "This could be because you hit a bug. It is also possible that this binary\n"
  96     "or one of the libraries it was linked against is corrupt, improperly built,\n"
  97     "or misconfigured. This error can also be caused by malfunctioning hardware.\n");
  98
  99   my_safe_printf_stderr("%s",
 100     "We will try our best to scrape up some info that will hopefully help\n"
 101     "diagnose the problem, but since we have already crashed, \n"
 102     "something is definitely wrong and this may fail.\n\n");
 103
 104   my_safe_printf_stderr("key_buffer_size=%lu\n",
 105                         (ulong) dflt_key_cache->key_cache_mem_size);
 106
 107   my_safe_printf_stderr("read_buffer_size=%ld\n",
 108                         (long) global_system_variables.read_buff_size);
 109
 110   my_safe_printf_stderr("max_used_connections=%lu\n",
 111                         (ulong) max_used_connections);
 112
 113   my_safe_printf_stderr("max_threads=%u\n",
 114                         (uint) thread_scheduler.max_threads);
 115
 116   my_safe_printf_stderr("thread_count=%u\n", (uint) thread_count);
 117
 118   my_safe_printf_stderr("connection_count=%u\n", (uint) connection_count);
 119
 120   my_safe_printf_stderr("It is possible that mysqld could use up to \n"
 121                         "key_buffer_size + "
 122                         "(read_buffer_size + sort_buffer_size)*max_threads = "
 123                         "%lu K  bytes of memory\n",
 124                         ((ulong) dflt_key_cache->key_cache_mem_size +
 125                          (global_system_variables.read_buff_size +
 126                           global_system_variables.sortbuff_size) *
 127                          thread_scheduler.max_threads +
 128                          max_connections * sizeof(THD)) / 1024);
 129
 130   my_safe_printf_stderr("%s",
 131     "Hope that's ok; if not, decrease some variables in the equation.\n\n");
 132
 133 #if defined(HAVE_LINUXTHREADS)
 134 #define UNSAFE_DEFAULT_LINUX_THREADS 200
 135   if (sizeof(char*) == 4 && thread_count > UNSAFE_DEFAULT_LINUX_THREADS)
 136   {
 137     my_safe_printf_stderr(
 138       "You seem to be running 32-bit Linux and have "
 139       "%d concurrent connections.\n"
 140       "If you have not changed STACK_SIZE in LinuxThreads "
 141       "and built the binary \n"
 142       "yourself, LinuxThreads is quite likely to steal "
 143       "a part of the global heap for\n"
 144       "the thread stack. Please read "
 145       "http://dev.mysql.com/doc/mysql/en/linux-installation.html\n\n"
 146       thread_count);
 147   }
 148 #endif /* HAVE_LINUXTHREADS */
 149
 150 #ifdef HAVE_STACKTRACE
 151   THD *thd=current_thd;
 152
 153   if (!(test_flags & TEST_NO_STACKTRACE))
 154   {
 155     my_safe_printf_stderr("Thread pointer: 0x%p\n", thd);
 156     my_safe_printf_stderr("%s",
 157       "Attempting backtrace. You can use the following "
 158       "information to find out\n"
 159       "where mysqld died. If you see no messages after this, something went\n"
 160       "terribly wrong...\n");
 161     my_print_stacktrace(thd ? (uchar*) thd->thread_stack : NULL,
 162                         my_thread_stack_size);
 163   }
 164   if (thd)
 165   {
 166     const char *kreason= "UNKNOWN";
 167     switch (thd->killed) {
 168     case THD::NOT_KILLED:
 169       kreason= "NOT_KILLED";
 170       break;
 171     case THD::KILL_BAD_DATA:
 172       kreason= "KILL_BAD_DATA";
 173       break;
 174     case THD::KILL_CONNECTION:
 175       kreason= "KILL_CONNECTION";
 176       break;
 177     case THD::KILL_QUERY:
 178       kreason= "KILL_QUERY";
 179       break;
 180     case THD::KILLED_NO_VALUE:
 181       kreason= "KILLED_NO_VALUE";
 182       break;
 183     }
 184     my_safe_printf_stderr("%s", "\n"
 185       "Trying to get some variables.\n"
 186       "Some pointers may be invalid and cause the dump to abort.\n");
 187
 188     my_safe_printf_stderr("Query (%p): ", thd->query());
 189     my_safe_print_str(thd->query(), min(1024U, thd->query_length()));
 190     my_safe_printf_stderr("Connection ID (thread ID): %lu\n",
 191                           (ulong) thd->thread_id);
 192     my_safe_printf_stderr("Status: %s\n\n", kreason);
 193   }
 194   my_safe_printf_stderr("%s",
 195     "The manual page at "
 196     "http://dev.mysql.com/doc/mysql/en/crashing.html contains\n"
 197     "information that should help you find out what is causing the crash.\n");
 198
 199 #endif /* HAVE_STACKTRACE */
 200
 201 #ifdef HAVE_INITGROUPS
 202   if (calling_initgroups)
 203   {
 204     my_safe_printf_stderr("%s", "\n"
 205       "This crash occured while the server was calling initgroups(). This is\n"
 206       "often due to the use of a mysqld that is statically linked against \n"
 207       "glibc and configured to use LDAP in /etc/nsswitch.conf.\n"
 208       "You will need to either upgrade to a version of glibc that does not\n"
 209       "have this problem (2.3.4 or later when used with nscd),\n"
 210       "disable LDAP in your nsswitch.conf, or use a "
 211       "mysqld that is not statically linked.\n");
 212   }
 213 #endif
 214
 215 #ifdef HAVE_NPTL
 216   if (thd_lib_detected == THD_LIB_LT && !ld_assume_kernel_is_set)
 217   {
 218     my_safe_printf_stderr("%s",
 219       "You are running a statically-linked LinuxThreads binary on an NPTL\n"
 220       "system. This can result in crashes on some distributions due to "
 221       "LT/NPTL conflicts.\n"
 222       "You should either build a dynamically-linked binary, "
 223       "or force LinuxThreads\n"
 224       "to be used with the LD_ASSUME_KERNEL environment variable.\n"
 225       "Please consult the documentation for your distribution "
 226       "on how to do that.\n");
 227   }
 228 #endif
 229
 230   if (locked_in_memory)
 231   {
 232     my_safe_printf_stderr("%s", "\n"
 233       "The \"--memlock\" argument, which was enabled, "
 234       "uses system calls that are\n"
 235       "unreliable and unstable on some operating systems and "
 236       "operating-system versions (notably, some versions of Linux).\n"
 237       "This crash could be due to use of those buggy OS calls.\n"
 238       "You should consider whether you really need the "
 239       "\"--memlock\" parameter and/or consult the OS distributer about "
 240       "\"mlockall\" bugs.\n");
 241   }
 242
 243 #ifdef HAVE_WRITE_CORE
 244   if (test_flags & TEST_CORE_ON_SIGNAL)
 245   {
 246     my_safe_printf_stderr("%s", "Writing a core file\n");
 247     my_write_core(sig);
 248   }
 249 #endif
 250
 251 #ifndef __WIN__
 252   /*
 253      Quit, without running destructors (etc.)
 254      On Windows, do not terminate, but pass control to exception filter.
 255   */
 256   _exit(1);  // Using _exit(), since exit() is not async signal safe
 257 #endif
 258 }