source/lib/fault.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Critical Fault handling
   4    Copyright (C) Andrew Tridgell 1992-1998
   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; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "includes.h"
  21
  22 #ifdef HAVE_SYS_PRCTL_H
  23 #include <sys/prctl.h>
  24 #endif
  25
  26 static void (*cont_fn)(void *);
  27 static char *corepath;
  28
  29 /*******************************************************************
  30 report a fault
  31 ********************************************************************/
  32 static void fault_report(int sig)
  33 {
  34         static int counter;
  35
  36         if (counter) _exit(1);
  37
  38         counter++;
  39
  40         DEBUGSEP(0);
  41         DEBUG(0,("INTERNAL ERROR: Signal %d in pid %d (%s)",sig,(int)sys_getpid(),SAMBA_VERSION_STRING));
  42         DEBUG(0,("\nPlease read the Trouble-Shooting section of the Samba3-HOWTO\n"));
  43         DEBUG(0,("\nFrom: http://www.samba.org/samba/docs/Samba3-HOWTO.pdf\n"));
  44         DEBUGSEP(0);
  45
  46         smb_panic("internal error");
  47
  48         if (cont_fn) {
  49                 cont_fn(NULL);
  50 #ifdef SIGSEGV
  51                 CatchSignal(SIGSEGV,SIGNAL_CAST SIG_DFL);
  52 #endif
  53 #ifdef SIGBUS
  54                 CatchSignal(SIGBUS,SIGNAL_CAST SIG_DFL);
  55 #endif
  56 #ifdef SIGABRT
  57                 CatchSignal(SIGABRT,SIGNAL_CAST SIG_DFL);
  58 #endif
  59                 return; /* this should cause a core dump */
  60         }
  61         exit(1);
  62 }
  63
  64 /****************************************************************************
  65 catch serious errors
  66 ****************************************************************************/
  67 static void sig_fault(int sig)
  68 {
  69         fault_report(sig);
  70 }
  71
  72 /*******************************************************************
  73 setup our fault handlers
  74 ********************************************************************/
  75 void fault_setup(void (*fn)(void *))
  76 {
  77         cont_fn = fn;
  78
  79 #ifdef SIGSEGV
  80         CatchSignal(SIGSEGV,SIGNAL_CAST sig_fault);
  81 #endif
  82 #ifdef SIGBUS
  83         CatchSignal(SIGBUS,SIGNAL_CAST sig_fault);
  84 #endif
  85 #ifdef SIGABRT
  86         CatchSignal(SIGABRT,SIGNAL_CAST sig_fault);
  87 #endif
  88 }
  89
  90 /*******************************************************************
  91 make all the preparations to safely dump a core file
  92 ********************************************************************/
  93
  94 void dump_core_setup(const char *progname)
  95 {
  96         char *logbase = NULL;
  97         char *end = NULL;
  98
  99         if (lp_logfile() && *lp_logfile()) {
 100                 if (asprintf(&logbase, "%s", lp_logfile()) < 0) {
 101                         return;
 102                 }
 103                 if ((end = strrchr_m(logbase, '/'))) {
 104                         *end = '\0';
 105                 }
 106         } else {
 107                 /* We will end up here is the log file is given on the command
 108                  * line by the -l option but the "log file" option is not set
 109                  * in smb.conf.
 110                  */
 111                 if (asprintf(&logbase, "%s", get_dyn_LOGFILEBASE()) < 0) {
 112                         return;
 113                 }
 114         }
 115
 116         SMB_ASSERT(progname != NULL);
 117
 118         if (asprintf(&corepath, "%s/cores", logbase) < 0) {
 119                 SAFE_FREE(logbase);
 120                 return;
 121         }
 122         mkdir(corepath,0700);
 123
 124         SAFE_FREE(corepath);
 125         if (asprintf(&corepath, "%s/cores/%s",
 126                         logbase, progname) < 0) {
 127                 SAFE_FREE(logbase);
 128                 return;
 129         }
 130         mkdir(corepath,0700);
 131
 132         sys_chown(corepath,getuid(),getgid());
 133         chmod(corepath,0700);
 134
 135         SAFE_FREE(logbase);
 136
 137 #ifdef HAVE_GETRLIMIT
 138 #ifdef RLIMIT_CORE
 139         {
 140                 struct rlimit rlp;
 141                 getrlimit(RLIMIT_CORE, &rlp);
 142                 rlp.rlim_cur = MAX(16*1024*1024,rlp.rlim_cur);
 143                 setrlimit(RLIMIT_CORE, &rlp);
 144                 getrlimit(RLIMIT_CORE, &rlp);
 145                 DEBUG(3,("Maximum core file size limits now %d(soft) %d(hard)\n",
 146                          (int)rlp.rlim_cur,(int)rlp.rlim_max));
 147         }
 148 #endif
 149 #endif
 150
 151 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
 152         /* On Linux we lose the ability to dump core when we change our user
 153          * ID. We know how to dump core safely, so let's make sure we have our
 154          * dumpable flag set.
 155          */
 156         prctl(PR_SET_DUMPABLE, 1);
 157 #endif
 158
 159         /* FIXME: if we have a core-plus-pid facility, configurably set
 160          * this up here.
 161          */
 162 }
 163
 164  void dump_core(void)
 165 {
 166         static bool called;
 167
 168         if (called) {
 169                 DEBUG(0, ("dump_core() called recursive\n"));
 170                 exit(1);
 171         }
 172         called = true;
 173
 174         /* Note that even if core dumping has been disabled, we still set up
 175          * the core path. This is to handle the case where core dumping is
 176          * turned on in smb.conf and the relevant daemon is not restarted.
 177          */
 178         if (!lp_enable_core_files()) {
 179                 DEBUG(0, ("Exiting on internal error (core file administratively disabled)\n"));
 180                 exit(1);
 181         }
 182
 183 #if DUMP_CORE
 184         /* If we're running as non root we might not be able to dump the core
 185          * file to the corepath.  There must not be an unbecome_root() before
 186          * we call abort(). */
 187         if (geteuid() != 0) {
 188                 become_root();
 189         }
 190
 191         if (corepath == NULL) {
 192                 DEBUG(0, ("Can not dump core: corepath not set up\n"));
 193                 exit(1);
 194         }
 195
 196         if (*corepath != '\0') {
 197                 /* The chdir might fail if we dump core before we finish
 198                  * processing the config file.
 199                  */
 200                 if (chdir(corepath) != 0) {
 201                         DEBUG(0, ("unable to change to %s\n", corepath));
 202                         DEBUGADD(0, ("refusing to dump core\n"));
 203                         exit(1);
 204                 }
 205
 206                 DEBUG(0,("dumping core in %s\n", corepath));
 207         }
 208
 209         umask(~(0700));
 210         dbgflush();
 211
 212         /* Ensure we don't have a signal handler for abort. */
 213 #ifdef SIGABRT
 214         CatchSignal(SIGABRT,SIGNAL_CAST SIG_DFL);
 215 #endif
 216
 217         abort();
 218
 219 #else /* DUMP_CORE */
 220         exit(1);
 221 #endif /* DUMP_CORE */
 222 }
 223