source4/smbd/process_thread.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    thread model: standard (1 thread per client connection)
   5
   6    Copyright (C) Andrew Tridgell 2003-2005
   7    Copyright (C) James J Myers 2003 <myersjj@samba.org>
   8    Copyright (C) Stefan (metze) Metzmacher 2004
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 2 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program; if not, write to the Free Software
  22    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  23 */
  24
  25 #include "includes.h"
  26 #include "version.h"
  27 #include <pthread.h>
  28 #ifdef HAVE_BACKTRACE
  29 #include <execinfo.h>
  30 #endif
  31 #include "system/wait.h"
  32 #include "system/filesys.h"
  33 #include "lib/events/events.h"
  34 #include "dlinklist.h"
  35 #include "smb_server/smb_server.h"
  36 #include "mutex.h"
  37
  38 struct new_conn_state {
  39         struct event_context *ev;
  40         struct socket_context *sock;
  41         void (*new_conn)(struct event_context *, struct socket_context *, uint32_t , void *);
  42         void *private;
  43 };
  44
  45 static void *thread_connection_fn(void *thread_parm)
  46 {
  47         struct new_conn_state *new_conn = talloc_get_type(thread_parm, struct new_conn_state);
  48
  49         new_conn->new_conn(new_conn->ev, new_conn->sock, pthread_self(), new_conn->private);
  50
  51         /* run this connection from here */
  52         event_loop_wait(new_conn->ev);
  53
  54         talloc_free(new_conn);
  55
  56         return NULL;
  57 }
  58
  59 /*
  60   called when a listening socket becomes readable
  61 */
  62 static void thread_accept_connection(struct event_context *ev,
  63                                      struct socket_context *sock,
  64                                      void (*new_conn)(struct event_context *, struct socket_context *,
  65                                                       uint32_t , void *),
  66                                      void *private)
  67 {
  68         NTSTATUS status;
  69         int rc;
  70         pthread_t thread_id;
  71         pthread_attr_t thread_attr;
  72         struct new_conn_state *state;
  73         struct event_context *ev2;
  74
  75         ev2 = event_context_init(ev);
  76         if (ev2 == NULL) return;
  77
  78         state = talloc(ev2, struct new_conn_state);
  79         if (state == NULL) {
  80                 talloc_free(ev2);
  81                 return;
  82         }
  83
  84         state->new_conn = new_conn;
  85         state->private  = private;
  86         state->ev       = ev2;
  87
  88         /* accept an incoming connection. */
  89         status = socket_accept(sock, &state->sock);
  90         if (!NT_STATUS_IS_OK(status)) {
  91                 talloc_free(ev2);
  92                 return;
  93         }
  94
  95         talloc_steal(state, state->sock);
  96
  97         pthread_attr_init(&thread_attr);
  98         pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED);
  99         rc = pthread_create(&thread_id, &thread_attr, thread_connection_fn, state);
 100         pthread_attr_destroy(&thread_attr);
 101         if (rc == 0) {
 102                 DEBUG(4,("accept_connection_thread: created thread_id=%lu for fd=%d\n",
 103                         (unsigned long int)thread_id, socket_get_fd(sock)));
 104         } else {
 105                 DEBUG(0,("accept_connection_thread: thread create failed for fd=%d, rc=%d\n", socket_get_fd(sock), rc));
 106                 talloc_free(ev2);
 107         }
 108 }
 109
 110
 111 struct new_task_state {
 112         struct event_context *ev;
 113         void (*new_task)(struct event_context *, uint32_t , void *);
 114         void *private;
 115 };
 116
 117 static void *thread_task_fn(void *thread_parm)
 118 {
 119         struct new_task_state *new_task = talloc_get_type(thread_parm, struct new_task_state);
 120
 121         new_task->new_task(new_task->ev, pthread_self(), new_task->private);
 122
 123         /* run this connection from here */
 124         event_loop_wait(new_task->ev);
 125
 126         talloc_free(new_task);
 127
 128         return NULL;
 129 }
 130
 131 /*
 132   called when a new task is needed
 133 */
 134 static void thread_new_task(struct event_context *ev,
 135                             void (*new_task)(struct event_context *, uint32_t , void *),
 136                             void *private)
 137 {
 138         int rc;
 139         pthread_t thread_id;
 140         pthread_attr_t thread_attr;
 141         struct new_task_state *state;
 142         struct event_context *ev2;
 143
 144         ev2 = event_context_init(ev);
 145         if (ev2 == NULL) return;
 146
 147         state = talloc(ev2, struct new_task_state);
 148         if (state == NULL) {
 149                 talloc_free(ev2);
 150                 return;
 151         }
 152
 153         state->new_task = new_task;
 154         state->private  = private;
 155         state->ev       = ev2;
 156
 157         pthread_attr_init(&thread_attr);
 158         pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED);
 159         rc = pthread_create(&thread_id, &thread_attr, thread_task_fn, state);
 160         pthread_attr_destroy(&thread_attr);
 161         if (rc == 0) {
 162                 DEBUG(4,("thread_new_task: created thread_id=%lu\n",
 163                          (unsigned long int)thread_id));
 164         } else {
 165                 DEBUG(0,("thread_new_task: thread create failed rc=%d\n", rc));
 166                 talloc_free(ev2);
 167         }
 168 }
 169
 170 /* called when a task goes down */
 171 static void thread_terminate(struct event_context *event_ctx, const char *reason)
 172 {
 173         DEBUG(10,("thread_terminate: reason[%s]\n",reason));
 174
 175         talloc_free(event_ctx);
 176
 177         /* terminate this thread */
 178         pthread_exit(NULL);  /* thread cleanup routine will do actual cleanup */
 179 }
 180
 181 /*
 182   mutex init function for thread model
 183 */
 184 static int thread_mutex_init(smb_mutex_t *mutex, const char *name)
 185 {
 186         pthread_mutex_t m = PTHREAD_MUTEX_INITIALIZER;
 187         mutex->mutex = memdup(&m, sizeof(m));
 188         if (! mutex->mutex) {
 189                 errno = ENOMEM;
 190                 return -1;
 191         }
 192         return pthread_mutex_init((pthread_mutex_t *)mutex->mutex, NULL);
 193 }
 194
 195 /*
 196   mutex destroy function for thread model
 197 */
 198 static int thread_mutex_destroy(smb_mutex_t *mutex, const char *name)
 199 {
 200         return pthread_mutex_destroy((pthread_mutex_t *)mutex->mutex);
 201 }
 202
 203 static void mutex_start_timer(struct timeval *tp1)
 204 {
 205         gettimeofday(tp1,NULL);
 206 }
 207
 208 static double mutex_end_timer(struct timeval tp1)
 209 {
 210         struct timeval tp2;
 211         gettimeofday(&tp2,NULL);
 212         return((tp2.tv_sec - tp1.tv_sec) +
 213                (tp2.tv_usec - tp1.tv_usec)*1.0e-6);
 214 }
 215
 216 /*
 217   mutex lock function for thread model
 218 */
 219 static int thread_mutex_lock(smb_mutex_t *mutexP, const char *name)
 220 {
 221         pthread_mutex_t *mutex = (pthread_mutex_t *)mutexP->mutex;
 222         int rc;
 223         double t;
 224         struct timeval tp1;
 225         /* Test below is ONLY for debugging */
 226         if ((rc = pthread_mutex_trylock(mutex))) {
 227                 if (rc == EBUSY) {
 228                         mutex_start_timer(&tp1);
 229                         printf("mutex lock: thread %d, lock %s not available\n",
 230                                 (uint32_t)pthread_self(), name);
 231                         print_suspicious_usage("mutex_lock", name);
 232                         pthread_mutex_lock(mutex);
 233                         t = mutex_end_timer(tp1);
 234                         printf("mutex lock: thread %d, lock %s now available, waited %g seconds\n",
 235                                 (uint32_t)pthread_self(), name, t);
 236                         return 0;
 237                 }
 238                 printf("mutex lock: thread %d, lock %s failed rc=%d\n",
 239                                 (uint32_t)pthread_self(), name, rc);
 240                 SMB_ASSERT(errno == 0); /* force error */
 241         }
 242         return 0;
 243 }
 244
 245 /*
 246    mutex unlock for thread model
 247 */
 248 static int thread_mutex_unlock(smb_mutex_t *mutex, const char *name)
 249 {
 250         return pthread_mutex_unlock((pthread_mutex_t *)mutex->mutex);
 251 }
 252
 253 /*****************************************************************
 254  Read/write lock routines.
 255 *****************************************************************/
 256 /*
 257   rwlock init function for thread model
 258 */
 259 static int thread_rwlock_init(smb_rwlock_t *rwlock, const char *name)
 260 {
 261         pthread_rwlock_t m = PTHREAD_RWLOCK_INITIALIZER;
 262         rwlock->rwlock = memdup(&m, sizeof(m));
 263         if (! rwlock->rwlock) {
 264                 errno = ENOMEM;
 265                 return -1;
 266         }
 267         return pthread_rwlock_init((pthread_rwlock_t *)rwlock->rwlock, NULL);
 268 }
 269
 270 /*
 271   rwlock destroy function for thread model
 272 */
 273 static int thread_rwlock_destroy(smb_rwlock_t *rwlock, const char *name)
 274 {
 275         return pthread_rwlock_destroy((pthread_rwlock_t *)rwlock->rwlock);
 276 }
 277
 278 /*
 279   rwlock lock for read function for thread model
 280 */
 281 static int thread_rwlock_lock_read(smb_rwlock_t *rwlockP, const char *name)
 282 {
 283         pthread_rwlock_t *rwlock = (pthread_rwlock_t *)rwlockP->rwlock;
 284         int rc;
 285         double t;
 286         struct timeval tp1;
 287         /* Test below is ONLY for debugging */
 288         if ((rc = pthread_rwlock_tryrdlock(rwlock))) {
 289                 if (rc == EBUSY) {
 290                         mutex_start_timer(&tp1);
 291                         printf("rwlock lock_read: thread %d, lock %s not available\n",
 292                                 (uint32_t)pthread_self(), name);
 293                         print_suspicious_usage("rwlock_lock_read", name);
 294                         pthread_rwlock_rdlock(rwlock);
 295                         t = mutex_end_timer(tp1);
 296                         printf("rwlock lock_read: thread %d, lock %s now available, waited %g seconds\n",
 297                                 (uint32_t)pthread_self(), name, t);
 298                         return 0;
 299                 }
 300                 printf("rwlock lock_read: thread %d, lock %s failed rc=%d\n",
 301                                 (uint32_t)pthread_self(), name, rc);
 302                 SMB_ASSERT(errno == 0); /* force error */
 303         }
 304         return 0;
 305 }
 306
 307 /*
 308   rwlock lock for write function for thread model
 309 */
 310 static int thread_rwlock_lock_write(smb_rwlock_t *rwlockP, const char *name)
 311 {
 312         pthread_rwlock_t *rwlock = (pthread_rwlock_t *)rwlockP->rwlock;
 313         int rc;
 314         double t;
 315         struct timeval tp1;
 316         /* Test below is ONLY for debugging */
 317         if ((rc = pthread_rwlock_trywrlock(rwlock))) {
 318                 if (rc == EBUSY) {
 319                         mutex_start_timer(&tp1);
 320                         printf("rwlock lock_write: thread %d, lock %s not available\n",
 321                                 (uint32_t)pthread_self(), name);
 322                         print_suspicious_usage("rwlock_lock_write", name);
 323                         pthread_rwlock_wrlock(rwlock);
 324                         t = mutex_end_timer(tp1);
 325                         printf("rwlock lock_write: thread %d, lock %s now available, waited %g seconds\n",
 326                                 (uint32_t)pthread_self(), name, t);
 327                         return 0;
 328                 }
 329                 printf("rwlock lock_write: thread %d, lock %s failed rc=%d\n",
 330                                 (uint32_t)pthread_self(), name, rc);
 331                 SMB_ASSERT(errno == 0); /* force error */
 332         }
 333         return 0;
 334 }
 335
 336
 337 /*
 338    rwlock unlock for thread model
 339 */
 340 static int thread_rwlock_unlock(smb_rwlock_t *rwlock, const char *name)
 341 {
 342         return pthread_rwlock_unlock((pthread_rwlock_t *)rwlock->rwlock);
 343 }
 344
 345 /*****************************************************************
 346  Log suspicious usage (primarily for possible thread-unsafe behavior.
 347 *****************************************************************/
 348 static void thread_log_suspicious_usage(const char* from, const char* info)
 349 {
 350         DEBUG(1,("log_suspicious_usage: from %s info='%s'\n", from, info));
 351 #ifdef HAVE_BACKTRACE
 352         {
 353                 void *addresses[10];
 354                 int num_addresses = backtrace(addresses, 8);
 355                 char **bt_symbols = backtrace_symbols(addresses, num_addresses);
 356                 int i;
 357
 358                 if (bt_symbols) {
 359                         for (i=0; i<num_addresses; i++) {
 360                                 DEBUG(1,("log_suspicious_usage: %s%s\n", DEBUGTAB(1), bt_symbols[i]));
 361                         }
 362                         free(bt_symbols);
 363                 }
 364         }
 365 #endif
 366 }
 367
 368 /*****************************************************************
 369  Log suspicious usage to stdout (primarily for possible thread-unsafe behavior.
 370  Used in mutex code where DEBUG calls would cause recursion.
 371 *****************************************************************/
 372 static void thread_print_suspicious_usage(const char* from, const char* info)
 373 {
 374         printf("log_suspicious_usage: from %s info='%s'\n", from, info);
 375 #ifdef HAVE_BACKTRACE
 376         {
 377                 void *addresses[10];
 378                 int num_addresses = backtrace(addresses, 8);
 379                 char **bt_symbols = backtrace_symbols(addresses, num_addresses);
 380                 int i;
 381
 382                 if (bt_symbols) {
 383                         for (i=0; i<num_addresses; i++) {
 384                                 printf("log_suspicious_usage: %s%s\n", DEBUGTAB(1), bt_symbols[i]);
 385                         }
 386                         free(bt_symbols);
 387                 }
 388         }
 389 #endif
 390 }
 391
 392 static uint32_t thread_get_task_id(void)
 393 {
 394         return (uint32_t)pthread_self();
 395 }
 396
 397 static void thread_log_task_id(int fd)
 398 {
 399         char *s;
 400
 401         asprintf(&s, "thread %u: ", (uint32_t)pthread_self());
 402         write(fd, s, strlen(s));
 403         free(s);
 404 }
 405
 406 /****************************************************************************
 407 catch serious errors
 408 ****************************************************************************/
 409 static void thread_sig_fault(int sig)
 410 {
 411         DEBUG(0,("===============================================================\n"));
 412         DEBUG(0,("TERMINAL ERROR: Recursive signal %d in thread %lu (%s)\n",sig,(unsigned long int)pthread_self(),SAMBA_VERSION_STRING));
 413         DEBUG(0,("===============================================================\n"));
 414         exit(1); /* kill the whole server for now */
 415 }
 416
 417 /*******************************************************************
 418 setup our recursive fault handlers
 419 ********************************************************************/
 420 static void thread_fault_setup(void)
 421 {
 422 #ifdef SIGSEGV
 423         CatchSignal(SIGSEGV,SIGNAL_CAST thread_sig_fault);
 424 #endif
 425 #ifdef SIGBUS
 426         CatchSignal(SIGBUS,SIGNAL_CAST thread_sig_fault);
 427 #endif
 428 #ifdef SIGABRT
 429         CatchSignal(SIGABRT,SIGNAL_CAST thread_sig_fault);
 430 #endif
 431 }
 432
 433 /*******************************************************************
 434 report a fault in a thread
 435 ********************************************************************/
 436 static void thread_fault_handler(int sig)
 437 {
 438         static int counter;
 439
 440         /* try to catch recursive faults */
 441         thread_fault_setup();
 442
 443         counter++;      /* count number of faults that have occurred */
 444
 445         DEBUG(0,("===============================================================\n"));
 446         DEBUG(0,("INTERNAL ERROR: Signal %d in thread %lu (%s)\n",sig,(unsigned long int)pthread_self(),SAMBA_VERSION_STRING));
 447         DEBUG(0,("Please read the file BUGS.txt in the distribution\n"));
 448         DEBUG(0,("===============================================================\n"));
 449 #ifdef HAVE_BACKTRACE
 450         {
 451                 void *addresses[10];
 452                 int num_addresses = backtrace(addresses, 8);
 453                 char **bt_symbols = backtrace_symbols(addresses, num_addresses);
 454                 int i;
 455
 456                 if (bt_symbols) {
 457                         for (i=0; i<num_addresses; i++) {
 458                                 DEBUG(1,("fault_report: %s%s\n", DEBUGTAB(1), bt_symbols[i]));
 459                         }
 460                         free(bt_symbols);
 461                 }
 462         }
 463 #endif
 464         pthread_exit(NULL); /* terminate failing thread only */
 465 }
 466
 467 /*
 468   called when the process model is selected
 469 */
 470 static void thread_model_init(struct event_context *event_context)
 471 {
 472         struct mutex_ops m_ops;
 473         struct debug_ops d_ops;
 474
 475         ZERO_STRUCT(m_ops);
 476         ZERO_STRUCT(d_ops);
 477
 478         /* register mutex/rwlock handlers */
 479         m_ops.mutex_init = thread_mutex_init;
 480         m_ops.mutex_lock = thread_mutex_lock;
 481         m_ops.mutex_unlock = thread_mutex_unlock;
 482         m_ops.mutex_destroy = thread_mutex_destroy;
 483
 484         m_ops.rwlock_init = thread_rwlock_init;
 485         m_ops.rwlock_lock_write = thread_rwlock_lock_write;
 486         m_ops.rwlock_lock_read = thread_rwlock_lock_read;
 487         m_ops.rwlock_unlock = thread_rwlock_unlock;
 488         m_ops.rwlock_destroy = thread_rwlock_destroy;
 489
 490         register_mutex_handlers("thread", &m_ops);
 491
 492         register_fault_handler("thread", thread_fault_handler);
 493
 494         d_ops.log_suspicious_usage = thread_log_suspicious_usage;
 495         d_ops.print_suspicious_usage = thread_print_suspicious_usage;
 496         d_ops.get_task_id = thread_get_task_id;
 497         d_ops.log_task_id = thread_log_task_id;
 498
 499         register_debug_handlers("thread", &d_ops);
 500 }
 501
 502
 503 static const struct model_ops thread_ops = {
 504         .name                   = "thread",
 505         .model_init             = thread_model_init,
 506         .accept_connection      = thread_accept_connection,
 507         .new_task               = thread_new_task,
 508         .terminate              = thread_terminate,
 509 };
 510
 511 /*
 512   initialise the thread process model, registering ourselves with the model subsystem
 513  */
 514 NTSTATUS process_model_thread_init(void)
 515 {
 516         NTSTATUS ret;
 517
 518         /* register ourselves with the PROCESS_MODEL subsystem. */
 519         ret = register_process_model(&thread_ops);
 520         if (!NT_STATUS_IS_OK(ret)) {
 521                 DEBUG(0,("Failed to register process_model 'thread'!\n"));
 522                 return ret;
 523         }
 524
 525         return ret;
 526 }