Drizzled Public API Documentation

signal_handler.cc
1 /* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
2  * vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
3  *
4  * Copyright (C) 2008 Sun Microsystems, Inc.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; version 2 of the License.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18  */
19 
20 #include <config.h>
21 
22 #include <signal.h>
23 
24 #include <drizzled/signal_handler.h>
25 #include <drizzled/drizzled.h>
26 #include <drizzled/session.h>
27 #include <drizzled/session/cache.h>
28 #include <drizzled/internal/my_sys.h>
29 #include <drizzled/probes.h>
30 #include <drizzled/plugin.h>
31 #include <drizzled/plugin/scheduler.h>
32 #include <drizzled/current_session.h>
33 #include <drizzled/util/backtrace.h>
34 #include <drizzled/statistics_variables.h>
35 #include <drizzled/system_variables.h>
36 
37 using namespace drizzled;
38 
39 static uint32_t killed_threads;
40 static bool segfaulted= false;
41 
42 /*
43  * We declare these extern "C" because they are passed to system callback functions
44  * and Sun Studio does not like it when those don't have C linkage. We prefix them
45  * because extern "C"-ing something effectively removes the namespace from the
46  * linker symbols, meaning they would be exporting symbols like "print_signal_warning
47  */
48 extern "C"
49 {
50 
51 void drizzled_print_signal_warning(int sig)
52 {
53  if (global_system_variables.log_warnings)
54  errmsg_printf(error::WARN, _("Got signal %d from thread %"PRIu32),
55  sig, global_thread_id);
56 #ifndef HAVE_BSD_SIGNALS
57  sigset_t set;
58  sigemptyset(&set);
59 
60  struct sigaction sa;
61  sa.sa_handler= drizzled_print_signal_warning;
62  sa.sa_mask= set;
63  sa.sa_flags= 0;
64  sigaction(sig, &sa, NULL); /* int. thread system calls */
65 #endif
66  if (sig == SIGALRM)
67  alarm(2); /* reschedule alarm */
68 }
69 
71 void drizzled_end_thread_signal(int )
72 {
73  Session *session= current_session;
74  if (session)
75  {
76  Session::shared_ptr session_ptr(session::Cache::find(session->getSessionId()));
77  if (not session_ptr) // We need to make we have a lock on session before we do anything with it.
78  return;
79 
80  killed_threads++;
81 
82  // We need to get the ID before we kill off the session
83  session_ptr->scheduler->killSessionNow(session_ptr);
84  DRIZZLE_CONNECTION_DONE(session_ptr->getSessionId());
85  }
86 }
87 
88 static void write_core(int sig)
89 {
90  signal(sig, SIG_DFL);
91 #ifdef HAVE_gcov
92  /*
93  For GCOV build, crashing will prevent the writing of code coverage
94  information from this process, causing gcov output to be incomplete.
95  So we force the writing of coverage information here before terminating.
96  */
97  extern void __gcov_flush(void);
98  __gcov_flush();
99 #endif
100  pthread_kill(pthread_self(), sig);
101 #if defined(P_MYID) && !defined(SCO)
102  /* On Solaris, the above kill is not enough */
103  sigsend(P_PID,P_MYID,sig);
104 #endif
105 }
106 
107 void drizzled_handle_segfault(int sig)
108 {
109  time_t curr_time;
110  struct tm tm;
111 
112  /*
113  Strictly speaking, one needs a mutex here
114  but since we have got SIGSEGV already, things are a mess
115  so not having the mutex is not as bad as possibly using a buggy
116  mutex - so we keep things simple
117  */
118  if (segfaulted)
119  {
120  fprintf(stderr, _("Fatal signal %d while backtracing\n"), sig);
121  exit(1);
122  }
123 
124  segfaulted= true;
125 
126  curr_time= time(NULL);
127  if(curr_time == (time_t)-1)
128  {
129  fprintf(stderr, _("Fatal: time() call failed\n"));
130  exit(1);
131  }
132 
133  localtime_r(&curr_time, &tm);
134 
135  fprintf(stderr,_("%02d%02d%02d %2d:%02d:%02d - drizzled got signal %d;\n"
136  "This could be because you hit a bug. It is also possible that "
137  "this binary\n or one of the libraries it was linked against is "
138  "corrupt, improperly built,\n or misconfigured. This error can "
139  "also be caused by malfunctioning hardware.\n"),
140  tm.tm_year % 100, tm.tm_mon+1, tm.tm_mday,
141  tm.tm_hour, tm.tm_min, tm.tm_sec,
142  sig);
143  fprintf(stderr, _("We will try our best to scrape up some info that "
144  "will hopefully help diagnose\n"
145  "the problem, but since we have already crashed, "
146  "something is definitely wrong\nand this may fail.\n\n"));
147  fprintf(stderr, "read_buffer_size=%ld\n", (long) global_system_variables.read_buff_size);
148  fprintf(stderr, "max_used_connections=%"PRIu64"\n", current_global_counters.max_used_connections);
149  fprintf(stderr, "connection_count=%u\n", uint32_t(connection_count));
150  fprintf(stderr, _("It is possible that drizzled could use up to \n"
151  "(read_buffer_size + sort_buffer_size)*thread_count\n"
152  "bytes of memory\n"
153  "Hope that's ok; if not, decrease some variables in the "
154  "equation.\n\n"));
155 
156  call_backtrace();
157 
158  write_core(sig);
159 
160  exit(1);
161 }
162 
163 } /* extern "C" */