lib/util/fault.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Critical Fault handling
   4    Copyright (C) Andrew Tridgell 1992-1998
   5    Copyright (C) Tim Prouty 2009
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "replace.h"
  22 #include "system/filesys.h"
  23 #include "system/wait.h"
  24 #include "version.h"
  25
  26 #ifdef HAVE_SYS_SYSCTL_H
  27 #include <sys/sysctl.h>
  28 #endif
  29
  30
  31 #ifdef HAVE_SYS_PRCTL_H
  32 #include <sys/prctl.h>
  33 #endif
  34
  35 #include "debug.h"
  36 #include "lib/util/signal.h" /* Avoid /usr/include/signal.h */
  37 #include "substitute.h"
  38 #include "fault.h"
  39
  40 static struct {
  41         bool disabled;
  42         smb_panic_handler_t panic_handler;
  43 } fault_state;
  44
  45
  46 /*******************************************************************
  47 setup variables used for fault handling
  48 ********************************************************************/
  49 void fault_configure(smb_panic_handler_t panic_handler)
  50 {
  51         fault_state.panic_handler = panic_handler;
  52 }
  53
  54
  55 /**
  56    disable setting up fault handlers
  57    This is used for the bind9 dlz module, as we
  58    don't want a Samba module in bind9 to override the bind
  59    fault handling
  60 **/
  61 _PUBLIC_ void fault_setup_disable(void)
  62 {
  63         fault_state.disabled = true;
  64 }
  65
  66
  67 /*******************************************************************
  68 report a fault
  69 ********************************************************************/
  70 static void fault_report(int sig)
  71 {
  72         static int counter;
  73
  74         if (counter) _exit(1);
  75
  76         counter++;
  77
  78         DEBUGSEP(0);
  79         DEBUG(0,("INTERNAL ERROR: Signal %d in pid %d (%s)",sig,(int)getpid(),SAMBA_VERSION_STRING));
  80         DEBUG(0,("\nPlease read the Trouble-Shooting section of the Samba HOWTO\n"));
  81         DEBUGSEP(0);
  82
  83         smb_panic("internal error");
  84
  85         /* smb_panic() never returns, so this is really redundant */
  86         exit(1);
  87 }
  88
  89 /****************************************************************************
  90 catch serious errors
  91 ****************************************************************************/
  92 static void sig_fault(int sig)
  93 {
  94         fault_report(sig);
  95 }
  96
  97 /*******************************************************************
  98 setup our fault handlers
  99 ********************************************************************/
 100 void fault_setup(void)
 101 {
 102         if (fault_state.disabled) {
 103                 return;
 104         }
 105 #if !defined(HAVE_DISABLE_FAULT_HANDLING)
 106 #ifdef SIGSEGV
 107         CatchSignal(SIGSEGV, sig_fault);
 108 #endif
 109 #ifdef SIGBUS
 110         CatchSignal(SIGBUS, sig_fault);
 111 #endif
 112 #ifdef SIGABRT
 113         CatchSignal(SIGABRT, sig_fault);
 114 #endif
 115 #endif
 116 }
 117
 118 _PUBLIC_ const char *panic_action = NULL;
 119
 120 /*
 121    default smb_panic() implementation
 122 */
 123 static void smb_panic_default(const char *why) _NORETURN_;
 124 static void smb_panic_default(const char *why)
 125 {
 126 #if defined(HAVE_PRCTL) && defined(PR_SET_PTRACER)
 127         /*
 128          * Make sure all children can attach a debugger.
 129          */
 130         prctl(PR_SET_PTRACER, getpid(), 0, 0, 0);
 131 #endif
 132
 133         if (panic_action && *panic_action) {
 134                 char cmdstring[200];
 135                 if (strlcpy(cmdstring, panic_action, sizeof(cmdstring)) < sizeof(cmdstring)) {
 136                         int result;
 137                         char pidstr[20];
 138                         snprintf(pidstr, sizeof(pidstr), "%d", (int) getpid());
 139                         all_string_sub(cmdstring, "%d", pidstr, sizeof(cmdstring));
 140                         DEBUG(0, ("smb_panic(): calling panic action [%s]\n", cmdstring));
 141                         result = system(cmdstring);
 142
 143                         if (result == -1)
 144                                 DEBUG(0, ("smb_panic(): fork failed in panic action: %s\n",
 145                                           strerror(errno)));
 146                         else
 147                                 DEBUG(0, ("smb_panic(): action returned status %d\n",
 148                                           WEXITSTATUS(result)));
 149                 }
 150         }
 151         DEBUG(0,("PANIC: %s\n", why));
 152
 153 #ifdef SIGABRT
 154         CatchSignal(SIGABRT, SIG_DFL);
 155 #endif
 156         abort();
 157 }
 158
 159
 160 /**
 161    Something really nasty happened - panic !
 162 **/
 163 _PUBLIC_ void smb_panic(const char *why)
 164 {
 165         if (fault_state.panic_handler) {
 166                 fault_state.panic_handler(why);
 167                 _exit(1);
 168         }
 169         smb_panic_default(why);
 170 }