nptl/nptl-init.c

   1 /* Copyright (C) 2002-2007, 2008, 2009, 2011 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <assert.h>
  21 #include <errno.h>
  22 #include <limits.h>
  23 #include <signal.h>
  24 #include <stdlib.h>
  25 #include <unistd.h>
  26 #include <sys/param.h>
  27 #include <sys/resource.h>
  28 #include <pthreadP.h>
  29 #include <atomic.h>
  30 #include <ldsodefs.h>
  31 #include <tls.h>
  32 #include <list.h>
  33 #include <fork.h>
  34 #include <version.h>
  35 #include <shlib-compat.h>
  36 #include <smp.h>
  37 #include <lowlevellock.h>
  38 #include <kernel-features.h>
  39
  40
  41 /* Size and alignment of static TLS block.  */
  42 size_t __static_tls_size;
  43 size_t __static_tls_align_m1;
  44
  45 #ifndef __ASSUME_SET_ROBUST_LIST
  46 /* Negative if we do not have the system call and we can use it.  */
  47 int __set_robust_list_avail;
  48 # define set_robust_list_not_avail() \
  49   __set_robust_list_avail = -1
  50 #else
  51 # define set_robust_list_not_avail() do { } while (0)
  52 #endif
  53
  54 #ifndef __ASSUME_FUTEX_CLOCK_REALTIME
  55 /* Nonzero if we do not have FUTEX_CLOCK_REALTIME.  */
  56 int __have_futex_clock_realtime;
  57 # define __set_futex_clock_realtime() \
  58   __have_futex_clock_realtime = 1
  59 #else
  60 #define __set_futex_clock_realtime() do { } while (0)
  61 #endif
  62
  63 /* Version of the library, used in libthread_db to detect mismatches.  */
  64 static const char nptl_version[] __attribute_used__ = VERSION;
  65
  66
  67 #ifndef SHARED
  68 extern void __libc_setup_tls (size_t tcbsize, size_t tcbalign);
  69 #endif
  70
  71 #ifdef SHARED
  72 static
  73 #else
  74 extern
  75 #endif
  76 void __nptl_set_robust (struct pthread *);
  77
  78 #ifdef SHARED
  79 static void nptl_freeres (void);
  80
  81
  82 static const struct pthread_functions pthread_functions =
  83   {
  84     .ptr_pthread_attr_destroy = __pthread_attr_destroy,
  85 # if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1)
  86     .ptr___pthread_attr_init_2_0 = __pthread_attr_init_2_0,
  87 # endif
  88     .ptr___pthread_attr_init_2_1 = __pthread_attr_init_2_1,
  89     .ptr_pthread_attr_getdetachstate = __pthread_attr_getdetachstate,
  90     .ptr_pthread_attr_setdetachstate = __pthread_attr_setdetachstate,
  91     .ptr_pthread_attr_getinheritsched = __pthread_attr_getinheritsched,
  92     .ptr_pthread_attr_setinheritsched = __pthread_attr_setinheritsched,
  93     .ptr_pthread_attr_getschedparam = __pthread_attr_getschedparam,
  94     .ptr_pthread_attr_setschedparam = __pthread_attr_setschedparam,
  95     .ptr_pthread_attr_getschedpolicy = __pthread_attr_getschedpolicy,
  96     .ptr_pthread_attr_setschedpolicy = __pthread_attr_setschedpolicy,
  97     .ptr_pthread_attr_getscope = __pthread_attr_getscope,
  98     .ptr_pthread_attr_setscope = __pthread_attr_setscope,
  99     .ptr_pthread_condattr_destroy = __pthread_condattr_destroy,
 100     .ptr_pthread_condattr_init = __pthread_condattr_init,
 101     .ptr___pthread_cond_broadcast = __pthread_cond_broadcast,
 102     .ptr___pthread_cond_destroy = __pthread_cond_destroy,
 103     .ptr___pthread_cond_init = __pthread_cond_init,
 104     .ptr___pthread_cond_signal = __pthread_cond_signal,
 105     .ptr___pthread_cond_wait = __pthread_cond_wait,
 106     .ptr___pthread_cond_timedwait = __pthread_cond_timedwait,
 107 # if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_3_2)
 108     .ptr___pthread_cond_broadcast_2_0 = __pthread_cond_broadcast_2_0,
 109     .ptr___pthread_cond_destroy_2_0 = __pthread_cond_destroy_2_0,
 110     .ptr___pthread_cond_init_2_0 = __pthread_cond_init_2_0,
 111     .ptr___pthread_cond_signal_2_0 = __pthread_cond_signal_2_0,
 112     .ptr___pthread_cond_wait_2_0 = __pthread_cond_wait_2_0,
 113     .ptr___pthread_cond_timedwait_2_0 = __pthread_cond_timedwait_2_0,
 114 # endif
 115     .ptr_pthread_equal = __pthread_equal,
 116     .ptr___pthread_exit = __pthread_exit,
 117     .ptr_pthread_getschedparam = __pthread_getschedparam,
 118     .ptr_pthread_setschedparam = __pthread_setschedparam,
 119     .ptr_pthread_mutex_destroy = INTUSE(__pthread_mutex_destroy),
 120     .ptr_pthread_mutex_init = INTUSE(__pthread_mutex_init),
 121     .ptr_pthread_mutex_lock = INTUSE(__pthread_mutex_lock),
 122     .ptr_pthread_mutex_unlock = INTUSE(__pthread_mutex_unlock),
 123     .ptr_pthread_self = __pthread_self,
 124     .ptr_pthread_setcancelstate = __pthread_setcancelstate,
 125     .ptr_pthread_setcanceltype = __pthread_setcanceltype,
 126     .ptr___pthread_cleanup_upto = __pthread_cleanup_upto,
 127     .ptr___pthread_once = __pthread_once_internal,
 128     .ptr___pthread_rwlock_rdlock = __pthread_rwlock_rdlock_internal,
 129     .ptr___pthread_rwlock_wrlock = __pthread_rwlock_wrlock_internal,
 130     .ptr___pthread_rwlock_unlock = __pthread_rwlock_unlock_internal,
 131     .ptr___pthread_key_create = __pthread_key_create_internal,
 132     .ptr___pthread_getspecific = __pthread_getspecific_internal,
 133     .ptr___pthread_setspecific = __pthread_setspecific_internal,
 134     .ptr__pthread_cleanup_push_defer = __pthread_cleanup_push_defer,
 135     .ptr__pthread_cleanup_pop_restore = __pthread_cleanup_pop_restore,
 136     .ptr_nthreads = &__nptl_nthreads,
 137     .ptr___pthread_unwind = &__pthread_unwind,
 138     .ptr__nptl_deallocate_tsd = __nptl_deallocate_tsd,
 139     .ptr__nptl_setxid = __nptl_setxid,
 140     /* For now only the stack cache needs to be freed.  */
 141     .ptr_freeres = nptl_freeres,
 142     .ptr_set_robust = __nptl_set_robust
 143   };
 144 # define ptr_pthread_functions &pthread_functions
 145 #else
 146 # define ptr_pthread_functions NULL
 147 #endif
 148
 149
 150 #ifdef SHARED
 151 /* This function is called indirectly from the freeres code in libc.  */
 152 static void
 153 __libc_freeres_fn_section
 154 nptl_freeres (void)
 155 {
 156   __unwind_freeres ();
 157   __free_stacks (0);
 158 }
 159
 160
 161 static
 162 #endif
 163 void
 164 __nptl_set_robust (struct pthread *self)
 165 {
 166   INTERNAL_SYSCALL_DECL (err);
 167   INTERNAL_SYSCALL (set_robust_list, err, 2, &self->robust_head,
 168                     sizeof (struct robust_list_head));
 169 }
 170
 171
 172 /* For asynchronous cancellation we use a signal.  This is the handler.  */
 173 static void
 174 sigcancel_handler (int sig, siginfo_t *si, void *ctx)
 175 {
 176 #ifdef __ASSUME_CORRECT_SI_PID
 177   /* Determine the process ID.  It might be negative if the thread is
 178      in the middle of a fork() call.  */
 179   pid_t pid = THREAD_GETMEM (THREAD_SELF, pid);
 180   if (__builtin_expect (pid < 0, 0))
 181     pid = -pid;
 182 #endif
 183
 184   /* Safety check.  It would be possible to call this function for
 185      other signals and send a signal from another process.  This is not
 186      correct and might even be a security problem.  Try to catch as
 187      many incorrect invocations as possible.  */
 188   if (sig != SIGCANCEL
 189 #ifdef __ASSUME_CORRECT_SI_PID
 190       /* Kernels before 2.5.75 stored the thread ID and not the process
 191          ID in si_pid so we skip this test.  */
 192       || si->si_pid != pid
 193 #endif
 194       || si->si_code != SI_TKILL)
 195     return;
 196
 197   struct pthread *self = THREAD_SELF;
 198
 199   int oldval = THREAD_GETMEM (self, cancelhandling);
 200   while (1)
 201     {
 202       /* We are canceled now.  When canceled by another thread this flag
 203          is already set but if the signal is directly send (internally or
 204          from another process) is has to be done here.  */
 205       int newval = oldval | CANCELING_BITMASK | CANCELED_BITMASK;
 206
 207       if (oldval == newval || (oldval & EXITING_BITMASK) != 0)
 208         /* Already canceled or exiting.  */
 209         break;
 210
 211       int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
 212                                               oldval);
 213       if (curval == oldval)
 214         {
 215           /* Set the return value.  */
 216           THREAD_SETMEM (self, result, PTHREAD_CANCELED);
 217
 218           /* Make sure asynchronous cancellation is still enabled.  */
 219           if ((newval & CANCELTYPE_BITMASK) != 0)
 220             /* Run the registered destructors and terminate the thread.  */
 221             __do_cancel ();
 222
 223           break;
 224         }
 225
 226       oldval = curval;
 227     }
 228 }
 229
 230
 231 struct xid_command *__xidcmd attribute_hidden;
 232
 233 /* For asynchronous cancellation we use a signal.  This is the handler.  */
 234 static void
 235 sighandler_setxid (int sig, siginfo_t *si, void *ctx)
 236 {
 237 #ifdef __ASSUME_CORRECT_SI_PID
 238   /* Determine the process ID.  It might be negative if the thread is
 239      in the middle of a fork() call.  */
 240   pid_t pid = THREAD_GETMEM (THREAD_SELF, pid);
 241   if (__builtin_expect (pid < 0, 0))
 242     pid = -pid;
 243 #endif
 244
 245   /* Safety check.  It would be possible to call this function for
 246      other signals and send a signal from another process.  This is not
 247      correct and might even be a security problem.  Try to catch as
 248      many incorrect invocations as possible.  */
 249   if (sig != SIGSETXID
 250 #ifdef __ASSUME_CORRECT_SI_PID
 251       /* Kernels before 2.5.75 stored the thread ID and not the process
 252          ID in si_pid so we skip this test.  */
 253       || si->si_pid != pid
 254 #endif
 255       || si->si_code != SI_TKILL)
 256     return;
 257
 258   INTERNAL_SYSCALL_DECL (err);
 259   INTERNAL_SYSCALL_NCS (__xidcmd->syscall_no, err, 3, __xidcmd->id[0],
 260                         __xidcmd->id[1], __xidcmd->id[2]);
 261
 262   /* Reset the SETXID flag.  */
 263   struct pthread *self = THREAD_SELF;
 264   int flags, newval;
 265   do
 266     {
 267       flags = THREAD_GETMEM (self, cancelhandling);
 268       newval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling,
 269                                           flags & ~SETXID_BITMASK, flags);
 270     }
 271   while (flags != newval);
 272
 273   /* And release the futex.  */
 274   self->setxid_futex = 1;
 275   lll_futex_wake (&self->setxid_futex, 1, LLL_PRIVATE);
 276
 277   if (atomic_decrement_val (&__xidcmd->cntr) == 0)
 278     lll_futex_wake (&__xidcmd->cntr, 1, LLL_PRIVATE);
 279 }
 280
 281
 282 /* When using __thread for this, we do it in libc so as not
 283    to give libpthread its own TLS segment just for this.  */
 284 extern void **__libc_dl_error_tsd (void) __attribute__ ((const));
 285
 286
 287 /* This can be set by the debugger before initialization is complete.  */
 288 static bool __nptl_initial_report_events __attribute_used__;
 289
 290 void
 291 __pthread_initialize_minimal_internal (void)
 292 {
 293 #ifndef SHARED
 294   /* Unlike in the dynamically linked case the dynamic linker has not
 295      taken care of initializing the TLS data structures.  */
 296   __libc_setup_tls (TLS_TCB_SIZE, TLS_TCB_ALIGN);
 297
 298   /* We must prevent gcc from being clever and move any of the
 299      following code ahead of the __libc_setup_tls call.  This function
 300      will initialize the thread register which is subsequently
 301      used.  */
 302   __asm __volatile ("");
 303 #endif
 304
 305   /* Minimal initialization of the thread descriptor.  */
 306   struct pthread *pd = THREAD_SELF;
 307   INTERNAL_SYSCALL_DECL (err);
 308   pd->pid = pd->tid = INTERNAL_SYSCALL (set_tid_address, err, 1, &pd->tid);
 309   THREAD_SETMEM (pd, specific[0], &pd->specific_1stblock[0]);
 310   THREAD_SETMEM (pd, user_stack, true);
 311   if (LLL_LOCK_INITIALIZER != 0)
 312     THREAD_SETMEM (pd, lock, LLL_LOCK_INITIALIZER);
 313 #if HP_TIMING_AVAIL
 314   THREAD_SETMEM (pd, cpuclock_offset, GL(dl_cpuclock_offset));
 315 #endif
 316
 317   /* Initialize the robust mutex data.  */
 318 #ifdef __PTHREAD_MUTEX_HAVE_PREV
 319   pd->robust_prev = &pd->robust_head;
 320 #endif
 321   pd->robust_head.list = &pd->robust_head;
 322 #ifdef __NR_set_robust_list
 323   pd->robust_head.futex_offset = (offsetof (pthread_mutex_t, __data.__lock)
 324                                   - offsetof (pthread_mutex_t,
 325                                               __data.__list.__next));
 326   int res = INTERNAL_SYSCALL (set_robust_list, err, 2, &pd->robust_head,
 327                               sizeof (struct robust_list_head));
 328   if (INTERNAL_SYSCALL_ERROR_P (res, err))
 329 #endif
 330     set_robust_list_not_avail ();
 331
 332 #ifndef __ASSUME_PRIVATE_FUTEX
 333   /* Private futexes are always used (at least internally) so that
 334      doing the test once this early is beneficial.  */
 335   {
 336     int word = 0;
 337     word = INTERNAL_SYSCALL (futex, err, 3, &word,
 338                             FUTEX_WAKE | FUTEX_PRIVATE_FLAG, 1);
 339     if (!INTERNAL_SYSCALL_ERROR_P (word, err))
 340       THREAD_SETMEM (pd, header.private_futex, FUTEX_PRIVATE_FLAG);
 341   }
 342
 343   /* Private futexes have been introduced earlier than the
 344      FUTEX_CLOCK_REALTIME flag.  We don't have to run the test if we
 345      know the former are not supported.  This also means we know the
 346      kernel will return ENOSYS for unknown operations.  */
 347   if (THREAD_GETMEM (pd, header.private_futex) != 0)
 348 #endif
 349 #ifndef __ASSUME_FUTEX_CLOCK_REALTIME
 350     {
 351       int word = 0;
 352       /* NB: the syscall actually takes six parameters.  The last is the
 353          bit mask.  But since we will not actually wait at all the value
 354          is irrelevant.  Given that passing six parameters is difficult
 355          on some architectures we just pass whatever random value the
 356          calling convention calls for to the kernel.  It causes no harm.  */
 357       word = INTERNAL_SYSCALL (futex, err, 5, &word,
 358                                FUTEX_WAIT_BITSET | FUTEX_CLOCK_REALTIME
 359                                | FUTEX_PRIVATE_FLAG, 1, NULL, 0);
 360       assert (INTERNAL_SYSCALL_ERROR_P (word, err));
 361       if (INTERNAL_SYSCALL_ERRNO (word, err) != ENOSYS)
 362         __set_futex_clock_realtime ();
 363     }
 364 #endif
 365
 366   /* Set initial thread's stack block from 0 up to __libc_stack_end.
 367      It will be bigger than it actually is, but for unwind.c/pt-longjmp.c
 368      purposes this is good enough.  */
 369   THREAD_SETMEM (pd, stackblock_size, (size_t) __libc_stack_end);
 370
 371   /* Initialize the list of all running threads with the main thread.  */
 372   INIT_LIST_HEAD (&__stack_user);
 373   list_add (&pd->list, &__stack_user);
 374
 375   /* Before initializing __stack_user, the debugger could not find us and
 376      had to set __nptl_initial_report_events.  Propagate its setting.  */
 377   THREAD_SETMEM (pd, report_events, __nptl_initial_report_events);
 378
 379   /* Install the cancellation signal handler.  If for some reason we
 380      cannot install the handler we do not abort.  Maybe we should, but
 381      it is only asynchronous cancellation which is affected.  */
 382   struct sigaction sa;
 383   sa.sa_sigaction = sigcancel_handler;
 384   sa.sa_flags = SA_SIGINFO;
 385   __sigemptyset (&sa.sa_mask);
 386
 387   (void) __libc_sigaction (SIGCANCEL, &sa, NULL);
 388
 389   /* Install the handle to change the threads' uid/gid.  */
 390   sa.sa_sigaction = sighandler_setxid;
 391   sa.sa_flags = SA_SIGINFO | SA_RESTART;
 392
 393   (void) __libc_sigaction (SIGSETXID, &sa, NULL);
 394
 395   /* The parent process might have left the signals blocked.  Just in
 396      case, unblock it.  We reuse the signal mask in the sigaction
 397      structure.  It is already cleared.  */
 398   __sigaddset (&sa.sa_mask, SIGCANCEL);
 399   __sigaddset (&sa.sa_mask, SIGSETXID);
 400   (void) INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_UNBLOCK, &sa.sa_mask,
 401                            NULL, _NSIG / 8);
 402
 403   /* Get the size of the static and alignment requirements for the TLS
 404      block.  */
 405   size_t static_tls_align;
 406   _dl_get_tls_static_info (&__static_tls_size, &static_tls_align);
 407
 408   /* Make sure the size takes all the alignments into account.  */
 409   if (STACK_ALIGN > static_tls_align)
 410     static_tls_align = STACK_ALIGN;
 411   __static_tls_align_m1 = static_tls_align - 1;
 412
 413   __static_tls_size = roundup (__static_tls_size, static_tls_align);
 414
 415   /* Determine the default allowed stack size.  This is the size used
 416      in case the user does not specify one.  */
 417   struct rlimit limit;
 418   if (getrlimit (RLIMIT_STACK, &limit) != 0
 419       || limit.rlim_cur == RLIM_INFINITY)
 420     /* The system limit is not usable.  Use an architecture-specific
 421        default.  */
 422     limit.rlim_cur = ARCH_STACK_DEFAULT_SIZE;
 423   else if (limit.rlim_cur < PTHREAD_STACK_MIN)
 424     /* The system limit is unusably small.
 425        Use the minimal size acceptable.  */
 426     limit.rlim_cur = PTHREAD_STACK_MIN;
 427
 428   /* Make sure it meets the minimum size that allocate_stack
 429      (allocatestack.c) will demand, which depends on the page size.  */
 430   const uintptr_t pagesz = __sysconf (_SC_PAGESIZE);
 431   const size_t minstack = pagesz + __static_tls_size + MINIMAL_REST_STACK;
 432   if (limit.rlim_cur < minstack)
 433     limit.rlim_cur = minstack;
 434
 435   /* Round the resource limit up to page size.  */
 436   limit.rlim_cur = (limit.rlim_cur + pagesz - 1) & -pagesz;
 437   __default_stacksize = limit.rlim_cur;
 438
 439 #ifdef SHARED
 440   /* Transfer the old value from the dynamic linker's internal location.  */
 441   *__libc_dl_error_tsd () = *(*GL(dl_error_catch_tsd)) ();
 442   GL(dl_error_catch_tsd) = &__libc_dl_error_tsd;
 443
 444   /* Make __rtld_lock_{,un}lock_recursive use pthread_mutex_{,un}lock,
 445      keep the lock count from the ld.so implementation.  */
 446   GL(dl_rtld_lock_recursive) = (void *) INTUSE (__pthread_mutex_lock);
 447   GL(dl_rtld_unlock_recursive) = (void *) INTUSE (__pthread_mutex_unlock);
 448   unsigned int rtld_lock_count = GL(dl_load_lock).mutex.__data.__count;
 449   GL(dl_load_lock).mutex.__data.__count = 0;
 450   while (rtld_lock_count-- > 0)
 451     INTUSE (__pthread_mutex_lock) (&GL(dl_load_lock).mutex);
 452
 453   GL(dl_make_stack_executable_hook) = &__make_stacks_executable;
 454 #endif
 455
 456   GL(dl_init_static_tls) = &__pthread_init_static_tls;
 457
 458   GL(dl_wait_lookup_done) = &__wait_lookup_done;
 459
 460   /* Register the fork generation counter with the libc.  */
 461 #ifndef TLS_MULTIPLE_THREADS_IN_TCB
 462   __libc_multiple_threads_ptr =
 463 #endif
 464     __libc_pthread_init (&__fork_generation, __reclaim_stacks,
 465                          ptr_pthread_functions);
 466
 467   /* Determine whether the machine is SMP or not.  */
 468   __is_smp = is_smp_system ();
 469 }
 470 strong_alias (__pthread_initialize_minimal_internal,
 471               __pthread_initialize_minimal)