source3/lib/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 "includes.h"
  22
  23 #ifdef HAVE_SYS_PRCTL_H
  24 #include <sys/prctl.h>
  25 #endif
  26
  27 static void (*cont_fn)(void *);
  28 static char *corepath;
  29
  30 /*******************************************************************
  31 report a fault
  32 ********************************************************************/
  33 static void fault_report(int sig)
  34 {
  35         static int counter;
  36
  37         if (counter) _exit(1);
  38
  39         counter++;
  40
  41         DEBUGSEP(0);
  42         DEBUG(0,("INTERNAL ERROR: Signal %d in pid %d (%s)",sig,(int)sys_getpid(),samba_version_string()));
  43         DEBUG(0,("\nPlease read the Trouble-Shooting section of the Samba3-HOWTO\n"));
  44         DEBUG(0,("\nFrom: http://www.samba.org/samba/docs/Samba3-HOWTO.pdf\n"));
  45         DEBUGSEP(0);
  46
  47         smb_panic("internal error");
  48
  49         if (cont_fn) {
  50                 cont_fn(NULL);
  51 #ifdef SIGSEGV
  52                 CatchSignal(SIGSEGV,SIGNAL_CAST SIG_DFL);
  53 #endif
  54 #ifdef SIGBUS
  55                 CatchSignal(SIGBUS,SIGNAL_CAST SIG_DFL);
  56 #endif
  57 #ifdef SIGABRT
  58                 CatchSignal(SIGABRT,SIGNAL_CAST SIG_DFL);
  59 #endif
  60                 return; /* this should cause a core dump */
  61         }
  62         exit(1);
  63 }
  64
  65 /****************************************************************************
  66 catch serious errors
  67 ****************************************************************************/
  68 static void sig_fault(int sig)
  69 {
  70         fault_report(sig);
  71 }
  72
  73 /*******************************************************************
  74 setup our fault handlers
  75 ********************************************************************/
  76 void fault_setup(void (*fn)(void *))
  77 {
  78         cont_fn = fn;
  79
  80 #ifdef SIGSEGV
  81         CatchSignal(SIGSEGV,SIGNAL_CAST sig_fault);
  82 #endif
  83 #ifdef SIGBUS
  84         CatchSignal(SIGBUS,SIGNAL_CAST sig_fault);
  85 #endif
  86 #ifdef SIGABRT
  87         CatchSignal(SIGABRT,SIGNAL_CAST sig_fault);
  88 #endif
  89 }
  90
  91 /**
  92  * Build up the default corepath as "<logbase>/cores/<progname>"
  93  */
  94 static char *get_default_corepath(const char *logbase, const char *progname)
  95 {
  96         char *tmp_corepath;
  97
  98         /* Setup core dir in logbase. */
  99         tmp_corepath = talloc_asprintf(NULL, "%s/cores", logbase);
 100         if (!tmp_corepath)
 101                 return NULL;
 102
 103         if ((mkdir(tmp_corepath, 0700) == -1) && errno != EEXIST)
 104                 goto err_out;
 105
 106         if (chmod(tmp_corepath, 0700) == -1)
 107                 goto err_out;
 108
 109         talloc_free(tmp_corepath);
 110
 111         /* Setup progname-specific core subdir */
 112         tmp_corepath = talloc_asprintf(NULL, "%s/cores/%s", logbase, progname);
 113         if (!tmp_corepath)
 114                 return NULL;
 115
 116         if (mkdir(tmp_corepath, 0700) == -1 && errno != EEXIST)
 117                 goto err_out;
 118
 119         if (chown(tmp_corepath, getuid(), getgid()) == -1)
 120                 goto err_out;
 121
 122         if (chmod(tmp_corepath, 0700) == -1)
 123                 goto err_out;
 124
 125         return tmp_corepath;
 126
 127  err_out:
 128         talloc_free(tmp_corepath);
 129         return NULL;
 130 }
 131
 132 /**
 133  * Get the FreeBSD corepath.
 134  *
 135  * On FreeBSD the current working directory is ignored when creating a core
 136  * file.  Instead the core directory is controlled via sysctl.  This consults
 137  * the value of "kern.corefile" so the correct corepath can be printed out
 138  * before dump_core() calls abort.
 139  */
 140 #if (defined(FREEBSD) && defined(HAVE_SYSCTLBYNAME))
 141 static char *get_freebsd_corepath(void)
 142 {
 143         char *tmp_corepath = NULL;
 144         char *end = NULL;
 145         size_t len = 128;
 146         int ret;
 147
 148         /* Loop with increasing sizes so we don't allocate too much. */
 149         do {
 150                 if (len > 1024)  {
 151                         goto err_out;
 152                 }
 153
 154                 tmp_corepath = (char *)talloc_realloc(NULL, tmp_corepath,
 155                                                       char, len);
 156                 if (!tmp_corepath) {
 157                         return NULL;
 158                 }
 159
 160                 ret = sysctlbyname("kern.corefile", tmp_corepath, &len, NULL,
 161                                    0);
 162                 if (ret == -1) {
 163                         if (errno != ENOMEM) {
 164                                 DEBUG(0, ("sysctlbyname failed getting "
 165                                           "kern.corefile %s\n",
 166                                           strerror(errno)));
 167                                 goto err_out;
 168                         }
 169
 170                         /* Not a large enough array, try a bigger one. */
 171                         len = len << 1;
 172                 }
 173         } while (ret == -1);
 174
 175         /* Strip off the common filename expansion */
 176         if ((end = strrchr_m(tmp_corepath, '/'))) {
 177                 *end = '\0';
 178         }
 179
 180         return tmp_corepath;
 181
 182  err_out:
 183         if (tmp_corepath) {
 184                 talloc_free(tmp_corepath);
 185         }
 186         return NULL;
 187 }
 188 #endif
 189
 190 /**
 191  * Try getting system-specific corepath if one exists.
 192  *
 193  * If the system doesn't define a corepath, then the default is used.
 194  */
 195 static char *get_corepath(const char *logbase, const char *progname)
 196 {
 197 #if (defined(FREEBSD) && defined(HAVE_SYSCTLBYNAME))
 198
 199         /* @todo: Add support for the linux corepath. */
 200
 201         char *tmp_corepath = NULL;
 202         tmp_corepath = get_freebsd_corepath();
 203
 204         /* If this has been set correctly, we're done. */
 205         if (tmp_corepath) {
 206                 return tmp_corepath;
 207         }
 208 #endif
 209
 210         /* Fall back to the default. */
 211         return get_default_corepath(logbase, progname);
 212 }
 213
 214 /*******************************************************************
 215 make all the preparations to safely dump a core file
 216 ********************************************************************/
 217
 218 void dump_core_setup(const char *progname)
 219 {
 220         char *logbase = NULL;
 221         char *end = NULL;
 222
 223         if (lp_logfile() && *lp_logfile()) {
 224                 if (asprintf(&logbase, "%s", lp_logfile()) < 0) {
 225                         return;
 226                 }
 227                 if ((end = strrchr_m(logbase, '/'))) {
 228                         *end = '\0';
 229                 }
 230         } else {
 231                 /* We will end up here if the log file is given on the command
 232                  * line by the -l option but the "log file" option is not set
 233                  * in smb.conf.
 234                  */
 235                 if (asprintf(&logbase, "%s", get_dyn_LOGFILEBASE()) < 0) {
 236                         return;
 237                 }
 238         }
 239
 240         SMB_ASSERT(progname != NULL);
 241
 242         corepath = get_corepath(logbase, progname);
 243         if (!corepath) {
 244                 DEBUG(0, ("Unable to setup corepath for %s: %s\n", progname,
 245                           strerror(errno)));
 246                 goto out;
 247         }
 248
 249
 250 #ifdef HAVE_GETRLIMIT
 251 #ifdef RLIMIT_CORE
 252         {
 253                 struct rlimit rlp;
 254                 getrlimit(RLIMIT_CORE, &rlp);
 255                 rlp.rlim_cur = MAX(16*1024*1024,rlp.rlim_cur);
 256                 setrlimit(RLIMIT_CORE, &rlp);
 257                 getrlimit(RLIMIT_CORE, &rlp);
 258                 DEBUG(3,("Maximum core file size limits now %d(soft) %d(hard)\n",
 259                          (int)rlp.rlim_cur,(int)rlp.rlim_max));
 260         }
 261 #endif
 262 #endif
 263
 264 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
 265         /* On Linux we lose the ability to dump core when we change our user
 266          * ID. We know how to dump core safely, so let's make sure we have our
 267          * dumpable flag set.
 268          */
 269         prctl(PR_SET_DUMPABLE, 1);
 270 #endif
 271
 272         /* FIXME: if we have a core-plus-pid facility, configurably set
 273          * this up here.
 274          */
 275  out:
 276         SAFE_FREE(logbase);
 277 }
 278
 279  void dump_core(void)
 280 {
 281         static bool called;
 282
 283         if (called) {
 284                 DEBUG(0, ("dump_core() called recursive\n"));
 285                 exit(1);
 286         }
 287         called = true;
 288
 289         /* Note that even if core dumping has been disabled, we still set up
 290          * the core path. This is to handle the case where core dumping is
 291          * turned on in smb.conf and the relevant daemon is not restarted.
 292          */
 293         if (!lp_enable_core_files()) {
 294                 DEBUG(0, ("Exiting on internal error (core file administratively disabled)\n"));
 295                 exit(1);
 296         }
 297
 298 #if DUMP_CORE
 299         /* If we're running as non root we might not be able to dump the core
 300          * file to the corepath.  There must not be an unbecome_root() before
 301          * we call abort(). */
 302         if (geteuid() != 0) {
 303                 become_root();
 304         }
 305
 306         if (corepath == NULL) {
 307                 DEBUG(0, ("Can not dump core: corepath not set up\n"));
 308                 exit(1);
 309         }
 310
 311         if (*corepath != '\0') {
 312                 /* The chdir might fail if we dump core before we finish
 313                  * processing the config file.
 314                  */
 315                 if (chdir(corepath) != 0) {
 316                         DEBUG(0, ("unable to change to %s\n", corepath));
 317                         DEBUGADD(0, ("refusing to dump core\n"));
 318                         exit(1);
 319                 }
 320
 321                 DEBUG(0,("dumping core in %s\n", corepath));
 322         }
 323
 324         umask(~(0700));
 325         dbgflush();
 326
 327         /* Ensure we don't have a signal handler for abort. */
 328 #ifdef SIGABRT
 329         CatchSignal(SIGABRT,SIGNAL_CAST SIG_DFL);
 330 #endif
 331
 332         abort();
 333
 334 #else /* DUMP_CORE */
 335         exit(1);
 336 #endif /* DUMP_CORE */
 337 }
 338