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_SYSCTL_H 24#include <sys/sysctl.h> 25#endif 26 27 28#ifdef HAVE_SYS_PRCTL_H 29#include <sys/prctl.h> 30#endif 31 32static void (*cont_fn)(void *); 33static char *corepath; 34 35/******************************************************************* 36report a fault 37********************************************************************/ 38static void fault_report(int sig) 39{ 40 static int counter; 41 42 if (counter) _exit(1); 43 44 counter++; 45 46 DEBUGSEP(0); 47 DEBUG(0,("INTERNAL ERROR: Signal %d in pid %d (%s)",sig,(int)sys_getpid(),samba_version_string())); 48 DEBUG(0,("\nPlease read the Trouble-Shooting section of the Samba3-HOWTO\n")); 49 DEBUG(0,("\nFrom: http://www.samba.org/samba/docs/Samba3-HOWTO.pdf\n")); 50 DEBUGSEP(0); 51 52 smb_panic("internal error"); 53 54 if (cont_fn) { 55 cont_fn(NULL); 56#ifdef SIGSEGV 57 CatchSignal(SIGSEGV,SIGNAL_CAST SIG_DFL); 58#endif 59#ifdef SIGBUS 60 CatchSignal(SIGBUS,SIGNAL_CAST SIG_DFL); 61#endif 62#ifdef SIGABRT 63 CatchSignal(SIGABRT,SIGNAL_CAST SIG_DFL); 64#endif 65 return; /* this should cause a core dump */ 66 } 67 exit(1); 68} 69 70/**************************************************************************** 71catch serious errors 72****************************************************************************/ 73static void sig_fault(int sig) 74{ 75 fault_report(sig); 76} 77 78/******************************************************************* 79setup our fault handlers 80********************************************************************/ 81void fault_setup(void (*fn)(void *)) 82{ 83 cont_fn = fn; 84 85#ifdef SIGSEGV 86 CatchSignal(SIGSEGV,SIGNAL_CAST sig_fault); 87#endif 88#ifdef SIGBUS 89 CatchSignal(SIGBUS,SIGNAL_CAST sig_fault); 90#endif 91#ifdef SIGABRT 92 CatchSignal(SIGABRT,SIGNAL_CAST sig_fault); 93#endif 94} 95 96/** 97 * Build up the default corepath as "<logbase>/cores/<progname>" 98 */ 99static char *get_default_corepath(const char *logbase, const char *progname) 100{ 101 char *tmp_corepath; 102 103 /* Setup core dir in logbase. */ 104 tmp_corepath = talloc_asprintf(NULL, "%s/cores", logbase); 105 if (!tmp_corepath) 106 return NULL; 107 108 if ((mkdir(tmp_corepath, 0700) == -1) && errno != EEXIST) 109 goto err_out; 110 111 if (chmod(tmp_corepath, 0700) == -1) 112 goto err_out; 113 114 talloc_free(tmp_corepath); 115 116 /* Setup progname-specific core subdir */ 117 tmp_corepath = talloc_asprintf(NULL, "%s/cores/%s", logbase, progname); 118 if (!tmp_corepath) 119 return NULL; 120 121 if (mkdir(tmp_corepath, 0700) == -1 && errno != EEXIST) 122 goto err_out; 123 124 if (chown(tmp_corepath, getuid(), getgid()) == -1) 125 goto err_out; 126 127 if (chmod(tmp_corepath, 0700) == -1) 128 goto err_out; 129 130 return tmp_corepath; 131 132 err_out: 133 talloc_free(tmp_corepath); 134 return NULL; 135} 136 137/** 138 * Get the FreeBSD corepath. 139 * 140 * On FreeBSD the current working directory is ignored when creating a core 141 * file. Instead the core directory is controlled via sysctl. This consults 142 * the value of "kern.corefile" so the correct corepath can be printed out 143 * before dump_core() calls abort. 144 */ 145#if (defined(FREEBSD) && defined(HAVE_SYSCTLBYNAME)) 146static char *get_freebsd_corepath(void) 147{ 148 char *tmp_corepath = NULL; 149 char *end = NULL; 150 size_t len = 128; 151 int ret; 152 153 /* Loop with increasing sizes so we don't allocate too much. */ 154 do { 155 if (len > 1024) { 156 goto err_out; 157 } 158 159 tmp_corepath = (char *)talloc_realloc(NULL, tmp_corepath, 160 char, len); 161 if (!tmp_corepath) { 162 return NULL; 163 } 164 165 ret = sysctlbyname("kern.corefile", tmp_corepath, &len, NULL, 166 0); 167 if (ret == -1) { 168 if (errno != ENOMEM) { 169 DEBUG(0, ("sysctlbyname failed getting " 170 "kern.corefile %s\n", 171 strerror(errno))); 172 goto err_out; 173 } 174 175 /* Not a large enough array, try a bigger one. */ 176 len = len << 1; 177 } 178 } while (ret == -1); 179 180 /* Strip off the common filename expansion */ 181 if ((end = strrchr_m(tmp_corepath, '/'))) { 182 *end = '\0'; 183 } 184 185 return tmp_corepath; 186 187 err_out: 188 if (tmp_corepath) { 189 talloc_free(tmp_corepath); 190 } 191 return NULL; 192} 193#endif 194 195/** 196 * Try getting system-specific corepath if one exists. 197 * 198 * If the system doesn't define a corepath, then the default is used. 199 */ 200static char *get_corepath(const char *logbase, const char *progname) 201{ 202#if (defined(FREEBSD) && defined(HAVE_SYSCTLBYNAME)) 203 204 /* @todo: Add support for the linux corepath. */ 205 206 char *tmp_corepath = NULL; 207 tmp_corepath = get_freebsd_corepath(); 208 209 /* If this has been set correctly, we're done. */ 210 if (tmp_corepath) { 211 return tmp_corepath; 212 } 213#endif 214 215 /* Fall back to the default. */ 216 return get_default_corepath(logbase, progname); 217} 218 219/******************************************************************* 220make all the preparations to safely dump a core file 221********************************************************************/ 222 223void dump_core_setup(const char *progname) 224{ 225 char *logbase = NULL; 226 char *end = NULL; 227 228 if (lp_logfile() && *lp_logfile()) { 229 if (asprintf(&logbase, "%s", lp_logfile()) < 0) { 230 return; 231 } 232 if ((end = strrchr_m(logbase, '/'))) { 233 *end = '\0'; 234 } 235 } else { 236 /* We will end up here if the log file is given on the command 237 * line by the -l option but the "log file" option is not set 238 * in smb.conf. 239 */ 240 if (asprintf(&logbase, "%s", get_dyn_LOGFILEBASE()) < 0) { 241 return; 242 } 243 } 244 245 SMB_ASSERT(progname != NULL); 246 247 corepath = get_corepath(logbase, progname); 248 if (!corepath) { 249 DEBUG(0, ("Unable to setup corepath for %s: %s\n", progname, 250 strerror(errno))); 251 goto out; 252 } 253 254 255#ifdef HAVE_GETRLIMIT 256#ifdef RLIMIT_CORE 257 { 258 struct rlimit rlp; 259 getrlimit(RLIMIT_CORE, &rlp); 260 rlp.rlim_cur = MAX(16*1024*1024,rlp.rlim_cur); 261 setrlimit(RLIMIT_CORE, &rlp); 262 getrlimit(RLIMIT_CORE, &rlp); 263 DEBUG(3,("Maximum core file size limits now %d(soft) %d(hard)\n", 264 (int)rlp.rlim_cur,(int)rlp.rlim_max)); 265 } 266#endif 267#endif 268 269#if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE) 270 /* On Linux we lose the ability to dump core when we change our user 271 * ID. We know how to dump core safely, so let's make sure we have our 272 * dumpable flag set. 273 */ 274 prctl(PR_SET_DUMPABLE, 1); 275#endif 276 277 /* FIXME: if we have a core-plus-pid facility, configurably set 278 * this up here. 279 */ 280 out: 281 SAFE_FREE(logbase); 282} 283 284 void dump_core(void) 285{ 286 static bool called; 287 288 if (called) { 289 DEBUG(0, ("dump_core() called recursive\n")); 290 exit(1); 291 } 292 called = true; 293 294 /* Note that even if core dumping has been disabled, we still set up 295 * the core path. This is to handle the case where core dumping is 296 * turned on in smb.conf and the relevant daemon is not restarted. 297 */ 298 if (!lp_enable_core_files()) { 299 DEBUG(0, ("Exiting on internal error (core file administratively disabled)\n")); 300 exit(1); 301 } 302 303#if DUMP_CORE 304 /* If we're running as non root we might not be able to dump the core 305 * file to the corepath. There must not be an unbecome_root() before 306 * we call abort(). */ 307 if (geteuid() != 0) { 308 become_root(); 309 } 310 311 if (corepath == NULL) { 312 DEBUG(0, ("Can not dump core: corepath not set up\n")); 313 exit(1); 314 } 315 316 if (*corepath != '\0') { 317 /* The chdir might fail if we dump core before we finish 318 * processing the config file. 319 */ 320 if (chdir(corepath) != 0) { 321 DEBUG(0, ("unable to change to %s\n", corepath)); 322 DEBUGADD(0, ("refusing to dump core\n")); 323 exit(1); 324 } 325 326 DEBUG(0,("dumping core in %s\n", corepath)); 327 } 328 329 umask(~(0700)); 330 dbgflush(); 331 332 /* Ensure we don't have a signal handler for abort. */ 333#ifdef SIGABRT 334 CatchSignal(SIGABRT,SIGNAL_CAST SIG_DFL); 335#endif 336 337 abort(); 338 339#else /* DUMP_CORE */ 340 exit(1); 341#endif /* DUMP_CORE */ 342} 343 344