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         if (mkdir(corepath,0700) == -1) {
 123                 if (errno != EEXIST) {
 124                         SAFE_FREE(corepath);
 125                         SAFE_FREE(logbase);
 126                         return;
 127                 }
 128         }
 129         if (chmod(corepath,0700) == -1) {
 130                 SAFE_FREE(corepath);
 131                 SAFE_FREE(logbase);
 132                 return;
 133         }
 134
 135         SAFE_FREE(corepath);
 136         if (asprintf(&corepath, "%s/cores/%s",
 137                         logbase, progname) < 0) {
 138                 SAFE_FREE(logbase);
 139                 return;
 140         }
 141         if (mkdir(corepath,0700) == -1) {
 142                 if (errno != EEXIST) {
 143                         SAFE_FREE(corepath);
 144                         SAFE_FREE(logbase);
 145                         return;
 146                 }
 147         }
 148
 149         if (sys_chown(corepath,getuid(),getgid()) == -1) {
 150                 SAFE_FREE(corepath);
 151                 SAFE_FREE(logbase);
 152                 return;
 153         }
 154         if (chmod(corepath,0700) == -1) {
 155                 SAFE_FREE(corepath);
 156                 SAFE_FREE(logbase);
 157                 return;
 158         }
 159
 160         SAFE_FREE(logbase);
 161
 162 #ifdef HAVE_GETRLIMIT
 163 #ifdef RLIMIT_CORE
 164         {
 165                 struct rlimit rlp;
 166                 getrlimit(RLIMIT_CORE, &rlp);
 167                 rlp.rlim_cur = MAX(16*1024*1024,rlp.rlim_cur);
 168                 setrlimit(RLIMIT_CORE, &rlp);
 169                 getrlimit(RLIMIT_CORE, &rlp);
 170                 DEBUG(3,("Maximum core file size limits now %d(soft) %d(hard)\n",
 171                          (int)rlp.rlim_cur,(int)rlp.rlim_max));
 172         }
 173 #endif
 174 #endif
 175
 176 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
 177         /* On Linux we lose the ability to dump core when we change our user
 178          * ID. We know how to dump core safely, so let's make sure we have our
 179          * dumpable flag set.
 180          */
 181         prctl(PR_SET_DUMPABLE, 1);
 182 #endif
 183
 184         /* FIXME: if we have a core-plus-pid facility, configurably set
 185          * this up here.
 186          */
 187 }
 188
 189  void dump_core(void)
 190 {
 191         static bool called;
 192
 193         if (called) {
 194                 DEBUG(0, ("dump_core() called recursive\n"));
 195                 exit(1);
 196         }
 197         called = true;
 198
 199         /* Note that even if core dumping has been disabled, we still set up
 200          * the core path. This is to handle the case where core dumping is
 201          * turned on in smb.conf and the relevant daemon is not restarted.
 202          */
 203         if (!lp_enable_core_files()) {
 204                 DEBUG(0, ("Exiting on internal error (core file administratively disabled)\n"));
 205                 exit(1);
 206         }
 207
 208 #if DUMP_CORE
 209         /* If we're running as non root we might not be able to dump the core
 210          * file to the corepath.  There must not be an unbecome_root() before
 211          * we call abort(). */
 212         if (geteuid() != 0) {
 213                 become_root();
 214         }
 215
 216         if (corepath == NULL) {
 217                 DEBUG(0, ("Can not dump core: corepath not set up\n"));
 218                 exit(1);
 219         }
 220
 221         if (*corepath != '\0') {
 222                 /* The chdir might fail if we dump core before we finish
 223                  * processing the config file.
 224                  */
 225                 if (chdir(corepath) != 0) {
 226                         DEBUG(0, ("unable to change to %s\n", corepath));
 227                         DEBUGADD(0, ("refusing to dump core\n"));
 228                         exit(1);
 229                 }
 230
 231                 DEBUG(0,("dumping core in %s\n", corepath));
 232         }
 233
 234         umask(~(0700));
 235         dbgflush();
 236
 237         /* Ensure we don't have a signal handler for abort. */
 238 #ifdef SIGABRT
 239         CatchSignal(SIGABRT,SIGNAL_CAST SIG_DFL);
 240 #endif
 241
 242         abort();
 243
 244 #else /* DUMP_CORE */
 245         exit(1);
 246 #endif /* DUMP_CORE */
 247 }
 248