source/smbd/process_thread.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    thread model: standard (1 thread per client connection)
   4    Copyright (C) Andrew Tridgell 2003
   5    Copyright (C) James J Myers 2003 <myersjj@samba.org>
   6    Copyright (C) Stefan (metze) Metzmacher 2004
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 #include "includes.h"
  24 #include "pthread.h"
  25 #ifdef HAVE_BACKTRACE
  26 #include "execinfo.h"
  27 #endif
  28
  29 static void *thread_connection_fn(void *thread_parm)
  30 {
  31         struct event_context *ev = thread_parm;
  32         /* wait for action */
  33         event_loop_wait(ev);
  34
  35 #if 0
  36         pthread_cleanup_pop(1);  /* will invoke terminate_mt_connection() */
  37 #endif
  38         return NULL;
  39 }
  40
  41 static int thread_get_id(struct smbsrv_request *req)
  42 {
  43         return (int)pthread_self();
  44 }
  45
  46 /*
  47   called when a listening socket becomes readable
  48 */
  49 static void thread_accept_connection(struct event_context *ev, struct fd_event *srv_fde,
  50                               time_t t, uint16_t flags)
  51 {
  52         NTSTATUS status;
  53         struct socket_context *sock;
  54         int rc;
  55         pthread_t thread_id;
  56         pthread_attr_t thread_attr;
  57         struct server_socket *server_socket = srv_fde->private;
  58         struct server_connection *conn;
  59
  60         /* accept an incoming connection. */
  61         status = socket_accept(server_socket->socket, &sock);
  62         if (!NT_STATUS_IS_OK(status)) {
  63                 DEBUG(0,("accept_connection_single: accept: %s\n",
  64                          nt_errstr(status)));
  65                 return;
  66         }
  67
  68         /* create new detached thread for this connection.  The new
  69            thread gets a new event_context with a single fd_event for
  70            receiving from the new socket. We set that thread running
  71            with the main event loop, then return. When we return the
  72            main event_context is continued.
  73         */
  74
  75         ev = event_context_init(server_socket);
  76         if (!ev) {
  77                 DEBUG(0,("thread_accept_connection: failed to create event_context!\n"));
  78                 socket_destroy(sock);
  79                 return;
  80         }
  81
  82         conn = server_setup_connection(ev, server_socket, sock, t, pthread_self());
  83         if (!conn) {
  84                 DEBUG(0,("server_setup_connection(ev, server_socket, sock, t) failed\n"));
  85                 event_context_destroy(ev);
  86                 socket_destroy(sock);
  87                 return;
  88         }
  89
  90         talloc_steal(conn, ev);
  91         talloc_steal(conn, sock);
  92
  93         /* TODO: is this MUTEX_LOCK in the right place here?
  94          *       --metze
  95          */
  96         MUTEX_LOCK_BY_ID(MUTEX_SMBD);
  97         DLIST_ADD(server_socket->connection_list,conn);
  98         MUTEX_UNLOCK_BY_ID(MUTEX_SMBD);
  99
 100         pthread_attr_init(&thread_attr);
 101         pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED);
 102         rc = pthread_create(&thread_id, &thread_attr, thread_connection_fn, ev);
 103         pthread_attr_destroy(&thread_attr);
 104         if (rc == 0) {
 105                 DEBUG(4,("accept_connection_thread: created thread_id=%lu for fd=%d\n",
 106                         (unsigned long int)thread_id, socket_get_fd(sock)));
 107         } else {
 108                 DEBUG(0,("accept_connection_thread: thread create failed for fd=%d, rc=%d\n", socket_get_fd(sock), rc));
 109                 event_context_destroy(ev);
 110                 socket_destroy(sock);
 111                 return;
 112         }
 113 }
 114
 115 /* called when a SMB connection goes down */
 116 static void thread_terminate_connection(struct server_connection *conn, const char *reason)
 117 {
 118         DEBUG(0,("thread_terminate_connection: reason[%s]\n",reason));
 119
 120         if (conn) {
 121                 talloc_free(conn);
 122         }
 123
 124         /* terminate this thread */
 125         pthread_exit(NULL);  /* thread cleanup routine will do actual cleanup */
 126 }
 127
 128 /*
 129   mutex init function for thread model
 130 */
 131 static int thread_mutex_init(smb_mutex_t *mutex, const char *name)
 132 {
 133         pthread_mutex_t m = PTHREAD_MUTEX_INITIALIZER;
 134         mutex->mutex = memdup(&m, sizeof(m));
 135         if (! mutex->mutex) {
 136                 errno = ENOMEM;
 137                 return -1;
 138         }
 139         return pthread_mutex_init((pthread_mutex_t *)mutex->mutex, NULL);
 140 }
 141
 142 /*
 143   mutex destroy function for thread model
 144 */
 145 static int thread_mutex_destroy(smb_mutex_t *mutex, const char *name)
 146 {
 147         return pthread_mutex_destroy((pthread_mutex_t *)mutex->mutex);
 148 }
 149
 150 static void mutex_start_timer(struct timeval *tp1)
 151 {
 152         gettimeofday(tp1,NULL);
 153 }
 154
 155 static double mutex_end_timer(struct timeval tp1)
 156 {
 157         struct timeval tp2;
 158         gettimeofday(&tp2,NULL);
 159         return((tp2.tv_sec - tp1.tv_sec) +
 160                (tp2.tv_usec - tp1.tv_usec)*1.0e-6);
 161 }
 162
 163 /*
 164   mutex lock function for thread model
 165 */
 166 static int thread_mutex_lock(smb_mutex_t *mutexP, const char *name)
 167 {
 168         pthread_mutex_t *mutex = (pthread_mutex_t *)mutexP->mutex;
 169         int rc;
 170         double t;
 171         struct timeval tp1;
 172         /* Test below is ONLY for debugging */
 173         if ((rc = pthread_mutex_trylock(mutex))) {
 174                 if (rc == EBUSY) {
 175                         mutex_start_timer(&tp1);
 176                         printf("mutex lock: thread %d, lock %s not available\n",
 177                                 (uint32_t)pthread_self(), name);
 178                         print_suspicious_usage("mutex_lock", name);
 179                         pthread_mutex_lock(mutex);
 180                         t = mutex_end_timer(tp1);
 181                         printf("mutex lock: thread %d, lock %s now available, waited %g seconds\n",
 182                                 (uint32_t)pthread_self(), name, t);
 183                         return 0;
 184                 }
 185                 printf("mutex lock: thread %d, lock %s failed rc=%d\n",
 186                                 (uint32_t)pthread_self(), name, rc);
 187                 SMB_ASSERT(errno == 0); /* force error */
 188         }
 189         return 0;
 190 }
 191
 192 /*
 193    mutex unlock for thread model
 194 */
 195 static int thread_mutex_unlock(smb_mutex_t *mutex, const char *name)
 196 {
 197         return pthread_mutex_unlock((pthread_mutex_t *)mutex->mutex);
 198 }
 199
 200 /*****************************************************************
 201  Read/write lock routines.
 202 *****************************************************************/
 203 /*
 204   rwlock init function for thread model
 205 */
 206 static int thread_rwlock_init(smb_rwlock_t *rwlock, const char *name)
 207 {
 208         pthread_rwlock_t m = PTHREAD_RWLOCK_INITIALIZER;
 209         rwlock->rwlock = memdup(&m, sizeof(m));
 210         if (! rwlock->rwlock) {
 211                 errno = ENOMEM;
 212                 return -1;
 213         }
 214         return pthread_rwlock_init((pthread_rwlock_t *)rwlock->rwlock, NULL);
 215 }
 216
 217 /*
 218   rwlock destroy function for thread model
 219 */
 220 static int thread_rwlock_destroy(smb_rwlock_t *rwlock, const char *name)
 221 {
 222         return pthread_rwlock_destroy((pthread_rwlock_t *)rwlock->rwlock);
 223 }
 224
 225 /*
 226   rwlock lock for read function for thread model
 227 */
 228 static int thread_rwlock_lock_read(smb_rwlock_t *rwlockP, const char *name)
 229 {
 230         pthread_rwlock_t *rwlock = (pthread_rwlock_t *)rwlockP->rwlock;
 231         int rc;
 232         double t;
 233         struct timeval tp1;
 234         /* Test below is ONLY for debugging */
 235         if ((rc = pthread_rwlock_tryrdlock(rwlock))) {
 236                 if (rc == EBUSY) {
 237                         mutex_start_timer(&tp1);
 238                         printf("rwlock lock_read: thread %d, lock %s not available\n",
 239                                 (uint32_t)pthread_self(), name);
 240                         print_suspicious_usage("rwlock_lock_read", name);
 241                         pthread_rwlock_rdlock(rwlock);
 242                         t = mutex_end_timer(tp1);
 243                         printf("rwlock lock_read: thread %d, lock %s now available, waited %g seconds\n",
 244                                 (uint32_t)pthread_self(), name, t);
 245                         return 0;
 246                 }
 247                 printf("rwlock lock_read: thread %d, lock %s failed rc=%d\n",
 248                                 (uint32_t)pthread_self(), name, rc);
 249                 SMB_ASSERT(errno == 0); /* force error */
 250         }
 251         return 0;
 252 }
 253
 254 /*
 255   rwlock lock for write function for thread model
 256 */
 257 static int thread_rwlock_lock_write(smb_rwlock_t *rwlockP, const char *name)
 258 {
 259         pthread_rwlock_t *rwlock = (pthread_rwlock_t *)rwlockP->rwlock;
 260         int rc;
 261         double t;
 262         struct timeval tp1;
 263         /* Test below is ONLY for debugging */
 264         if ((rc = pthread_rwlock_trywrlock(rwlock))) {
 265                 if (rc == EBUSY) {
 266                         mutex_start_timer(&tp1);
 267                         printf("rwlock lock_write: thread %d, lock %s not available\n",
 268                                 (uint32_t)pthread_self(), name);
 269                         print_suspicious_usage("rwlock_lock_write", name);
 270                         pthread_rwlock_wrlock(rwlock);
 271                         t = mutex_end_timer(tp1);
 272                         printf("rwlock lock_write: thread %d, lock %s now available, waited %g seconds\n",
 273                                 (uint32_t)pthread_self(), name, t);
 274                         return 0;
 275                 }
 276                 printf("rwlock lock_write: thread %d, lock %s failed rc=%d\n",
 277                                 (uint32_t)pthread_self(), name, rc);
 278                 SMB_ASSERT(errno == 0); /* force error */
 279         }
 280         return 0;
 281 }
 282
 283
 284 /*
 285    rwlock unlock for thread model
 286 */
 287 static int thread_rwlock_unlock(smb_rwlock_t *rwlock, const char *name)
 288 {
 289         return pthread_rwlock_unlock((pthread_rwlock_t *)rwlock->rwlock);
 290 }
 291
 292 /*****************************************************************
 293  Log suspicious usage (primarily for possible thread-unsafe behavior.
 294 *****************************************************************/
 295 static void thread_log_suspicious_usage(const char* from, const char* info)
 296 {
 297         DEBUG(1,("log_suspicious_usage: from %s info='%s'\n", from, info));
 298 #ifdef HAVE_BACKTRACE
 299         {
 300                 void *addresses[10];
 301                 int num_addresses = backtrace(addresses, 8);
 302                 char **bt_symbols = backtrace_symbols(addresses, num_addresses);
 303                 int i;
 304
 305                 if (bt_symbols) {
 306                         for (i=0; i<num_addresses; i++) {
 307                                 DEBUG(1,("log_suspicious_usage: %s%s\n", DEBUGTAB(1), bt_symbols[i]));
 308                         }
 309                         free(bt_symbols);
 310                 }
 311         }
 312 #endif
 313 }
 314
 315 /*****************************************************************
 316  Log suspicious usage to stdout (primarily for possible thread-unsafe behavior.
 317  Used in mutex code where DEBUG calls would cause recursion.
 318 *****************************************************************/
 319 static void thread_print_suspicious_usage(const char* from, const char* info)
 320 {
 321         printf("log_suspicious_usage: from %s info='%s'\n", from, info);
 322 #ifdef HAVE_BACKTRACE
 323         {
 324                 void *addresses[10];
 325                 int num_addresses = backtrace(addresses, 8);
 326                 char **bt_symbols = backtrace_symbols(addresses, num_addresses);
 327                 int i;
 328
 329                 if (bt_symbols) {
 330                         for (i=0; i<num_addresses; i++) {
 331                                 printf("log_suspicious_usage: %s%s\n", DEBUGTAB(1), bt_symbols[i]);
 332                         }
 333                         free(bt_symbols);
 334                 }
 335         }
 336 #endif
 337 }
 338
 339 static uint32_t thread_get_task_id(void)
 340 {
 341         return (uint32_t)pthread_self();
 342 }
 343
 344 static void thread_log_task_id(int fd)
 345 {
 346         char *s;
 347
 348         asprintf(&s, "thread %u: ", (uint32_t)pthread_self());
 349         write(fd, s, strlen(s));
 350         free(s);
 351 }
 352 /****************************************************************************
 353 catch serious errors
 354 ****************************************************************************/
 355 static void thread_sig_fault(int sig)
 356 {
 357         DEBUG(0,("===============================================================\n"));
 358         DEBUG(0,("TERMINAL ERROR: Recursive signal %d in thread %lu (%s)\n",sig,(unsigned long int)pthread_self(),SAMBA_VERSION_STRING));
 359         DEBUG(0,("===============================================================\n"));
 360         exit(1); /* kill the whole server for now */
 361 }
 362
 363 /*******************************************************************
 364 setup our recursive fault handlers
 365 ********************************************************************/
 366 static void thread_fault_setup(void)
 367 {
 368 #ifdef SIGSEGV
 369         CatchSignal(SIGSEGV,SIGNAL_CAST thread_sig_fault);
 370 #endif
 371 #ifdef SIGBUS
 372         CatchSignal(SIGBUS,SIGNAL_CAST thread_sig_fault);
 373 #endif
 374 #ifdef SIGABRT
 375         CatchSignal(SIGABRT,SIGNAL_CAST thread_sig_fault);
 376 #endif
 377 }
 378
 379 /*******************************************************************
 380 report a fault in a thread
 381 ********************************************************************/
 382 static void thread_fault_handler(int sig)
 383 {
 384         static int counter;
 385
 386         /* try to catch recursive faults */
 387         thread_fault_setup();
 388
 389         counter++;      /* count number of faults that have occurred */
 390
 391         DEBUG(0,("===============================================================\n"));
 392         DEBUG(0,("INTERNAL ERROR: Signal %d in thread %lu (%s)\n",sig,(unsigned long int)pthread_self(),SAMBA_VERSION_STRING));
 393         DEBUG(0,("Please read the file BUGS.txt in the distribution\n"));
 394         DEBUG(0,("===============================================================\n"));
 395 #ifdef HAVE_BACKTRACE
 396         {
 397                 void *addresses[10];
 398                 int num_addresses = backtrace(addresses, 8);
 399                 char **bt_symbols = backtrace_symbols(addresses, num_addresses);
 400                 int i;
 401
 402                 if (bt_symbols) {
 403                         for (i=0; i<num_addresses; i++) {
 404                                 DEBUG(1,("fault_report: %s%s\n", DEBUGTAB(1), bt_symbols[i]));
 405                         }
 406                         free(bt_symbols);
 407                 }
 408         }
 409 #endif
 410         pthread_exit(NULL); /* terminate failing thread only */
 411 }
 412
 413 /*
 414   called when the process model is selected
 415 */
 416 static void thread_model_startup(void)
 417 {
 418         struct mutex_ops m_ops;
 419         struct debug_ops d_ops;
 420
 421         ZERO_STRUCT(m_ops);
 422         ZERO_STRUCT(d_ops);
 423
 424         smbd_process_init();
 425
 426         /* register mutex/rwlock handlers */
 427         m_ops.mutex_init = thread_mutex_init;
 428         m_ops.mutex_lock = thread_mutex_lock;
 429         m_ops.mutex_unlock = thread_mutex_unlock;
 430         m_ops.mutex_destroy = thread_mutex_destroy;
 431
 432         m_ops.rwlock_init = thread_rwlock_init;
 433         m_ops.rwlock_lock_write = thread_rwlock_lock_write;
 434         m_ops.rwlock_lock_read = thread_rwlock_lock_read;
 435         m_ops.rwlock_unlock = thread_rwlock_unlock;
 436         m_ops.rwlock_destroy = thread_rwlock_destroy;
 437
 438         register_mutex_handlers("thread", &m_ops);
 439
 440         register_fault_handler("thread", thread_fault_handler);
 441
 442         d_ops.log_suspicious_usage = thread_log_suspicious_usage;
 443         d_ops.print_suspicious_usage = thread_print_suspicious_usage;
 444         d_ops.get_task_id = thread_get_task_id;
 445         d_ops.log_task_id = thread_log_task_id;
 446
 447         register_debug_handlers("thread", &d_ops);
 448 }
 449
 450 static void thread_exit_server(struct server_context *srv_ctx, const char *reason)
 451 {
 452         DEBUG(1,("thread_exit_server: reason[%s]\n",reason));
 453 }
 454
 455 /*
 456   initialise the thread process model, registering ourselves with the model subsystem
 457  */
 458 NTSTATUS process_model_thread_init(void)
 459 {
 460         NTSTATUS ret;
 461         struct model_ops ops;
 462
 463         ZERO_STRUCT(ops);
 464
 465         /* fill in our name */
 466         ops.name = "thread";
 467
 468         /* fill in all the operations */
 469         ops.model_startup = thread_model_startup;
 470         ops.accept_connection = thread_accept_connection;
 471         ops.terminate_connection = thread_terminate_connection;
 472         ops.exit_server = thread_exit_server;
 473         ops.get_id = thread_get_id;
 474
 475         /* register ourselves with the PROCESS_MODEL subsystem. */
 476         ret = register_backend("process_model", &ops);
 477         if (!NT_STATUS_IS_OK(ret)) {
 478                 DEBUG(0,("Failed to register process_model 'thread'!\n"));
 479                 return ret;
 480         }
 481
 482         return ret;
 483 }