nptl/init.c

   1 /* Copyright (C) 2002,2003,2004,2005,2006,2007 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 <limits.h>
  22 #include <signal.h>
  23 #include <stdlib.h>
  24 #include <unistd.h>
  25 #include <sys/param.h>
  26 #include <sys/resource.h>
  27 #include <pthreadP.h>
  28 #include <atomic.h>
  29 #include <ldsodefs.h>
  30 #include <tls.h>
  31 #include <fork.h>
  32 #include <version.h>
  33 #include <shlib-compat.h>
  34 #include <smp.h>
  35 #include <lowlevellock.h>
  36
  37
  38 /* Size and alignment of static TLS block.  */
  39 size_t __static_tls_size;
  40 size_t __static_tls_align_m1;
  41
  42 #ifndef __ASSUME_SET_ROBUST_LIST
  43 /* Negative if we do not have the system call and we can use it.  */
  44 int __set_robust_list_avail;
  45 # define set_robust_list_not_avail() \
  46   __set_robust_list_avail = -1
  47 #else
  48 # define set_robust_list_not_avail() do { } while (0)
  49 #endif
  50
  51 /* Version of the library, used in libthread_db to detect mismatches.  */
  52 static const char nptl_version[] __attribute_used__ = VERSION;
  53
  54
  55 #ifndef SHARED
  56 extern void __libc_setup_tls (size_t tcbsize, size_t tcbalign);
  57 #endif
  58
  59
  60 #ifdef SHARED
  61 static const struct pthread_functions pthread_functions =
  62   {
  63     .ptr_pthread_attr_destroy = __pthread_attr_destroy,
  64 # if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1)
  65     .ptr___pthread_attr_init_2_0 = __pthread_attr_init_2_0,
  66 # endif
  67     .ptr___pthread_attr_init_2_1 = __pthread_attr_init_2_1,
  68     .ptr_pthread_attr_getdetachstate = __pthread_attr_getdetachstate,
  69     .ptr_pthread_attr_setdetachstate = __pthread_attr_setdetachstate,
  70     .ptr_pthread_attr_getinheritsched = __pthread_attr_getinheritsched,
  71     .ptr_pthread_attr_setinheritsched = __pthread_attr_setinheritsched,
  72     .ptr_pthread_attr_getschedparam = __pthread_attr_getschedparam,
  73     .ptr_pthread_attr_setschedparam = __pthread_attr_setschedparam,
  74     .ptr_pthread_attr_getschedpolicy = __pthread_attr_getschedpolicy,
  75     .ptr_pthread_attr_setschedpolicy = __pthread_attr_setschedpolicy,
  76     .ptr_pthread_attr_getscope = __pthread_attr_getscope,
  77     .ptr_pthread_attr_setscope = __pthread_attr_setscope,
  78     .ptr_pthread_condattr_destroy = __pthread_condattr_destroy,
  79     .ptr_pthread_condattr_init = __pthread_condattr_init,
  80     .ptr___pthread_cond_broadcast = __pthread_cond_broadcast,
  81     .ptr___pthread_cond_destroy = __pthread_cond_destroy,
  82     .ptr___pthread_cond_init = __pthread_cond_init,
  83     .ptr___pthread_cond_signal = __pthread_cond_signal,
  84     .ptr___pthread_cond_wait = __pthread_cond_wait,
  85     .ptr___pthread_cond_timedwait = __pthread_cond_timedwait,
  86 # if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_3_2)
  87     .ptr___pthread_cond_broadcast_2_0 = __pthread_cond_broadcast_2_0,
  88     .ptr___pthread_cond_destroy_2_0 = __pthread_cond_destroy_2_0,
  89     .ptr___pthread_cond_init_2_0 = __pthread_cond_init_2_0,
  90     .ptr___pthread_cond_signal_2_0 = __pthread_cond_signal_2_0,
  91     .ptr___pthread_cond_wait_2_0 = __pthread_cond_wait_2_0,
  92     .ptr___pthread_cond_timedwait_2_0 = __pthread_cond_timedwait_2_0,
  93 # endif
  94     .ptr_pthread_equal = __pthread_equal,
  95     .ptr___pthread_exit = __pthread_exit,
  96     .ptr_pthread_getschedparam = __pthread_getschedparam,
  97     .ptr_pthread_setschedparam = __pthread_setschedparam,
  98     .ptr_pthread_mutex_destroy = INTUSE(__pthread_mutex_destroy),
  99     .ptr_pthread_mutex_init = INTUSE(__pthread_mutex_init),
 100     .ptr_pthread_mutex_lock = INTUSE(__pthread_mutex_lock),
 101     .ptr_pthread_mutex_unlock = INTUSE(__pthread_mutex_unlock),
 102     .ptr_pthread_self = __pthread_self,
 103     .ptr_pthread_setcancelstate = __pthread_setcancelstate,
 104     .ptr_pthread_setcanceltype = __pthread_setcanceltype,
 105     .ptr___pthread_cleanup_upto = __pthread_cleanup_upto,
 106     .ptr___pthread_once = __pthread_once_internal,
 107     .ptr___pthread_rwlock_rdlock = __pthread_rwlock_rdlock_internal,
 108     .ptr___pthread_rwlock_wrlock = __pthread_rwlock_wrlock_internal,
 109     .ptr___pthread_rwlock_unlock = __pthread_rwlock_unlock_internal,
 110     .ptr___pthread_key_create = __pthread_key_create_internal,
 111     .ptr___pthread_getspecific = __pthread_getspecific_internal,
 112     .ptr___pthread_setspecific = __pthread_setspecific_internal,
 113     .ptr__pthread_cleanup_push_defer = __pthread_cleanup_push_defer,
 114     .ptr__pthread_cleanup_pop_restore = __pthread_cleanup_pop_restore,
 115     .ptr_nthreads = &__nptl_nthreads,
 116     .ptr___pthread_unwind = &__pthread_unwind,
 117     .ptr__nptl_deallocate_tsd = __nptl_deallocate_tsd,
 118     .ptr__nptl_setxid = __nptl_setxid,
 119     /* For now only the stack cache needs to be freed.  */
 120     .ptr_freeres = __free_stack_cache
 121   };
 122 # define ptr_pthread_functions &pthread_functions
 123 #else
 124 # define ptr_pthread_functions NULL
 125 #endif
 126
 127
 128 /* For asynchronous cancellation we use a signal.  This is the handler.  */
 129 static void
 130 sigcancel_handler (int sig, siginfo_t *si, void *ctx)
 131 {
 132 #ifdef __ASSUME_CORRECT_SI_PID
 133   /* Determine the process ID.  It might be negative if the thread is
 134      in the middle of a fork() call.  */
 135   pid_t pid = THREAD_GETMEM (THREAD_SELF, pid);
 136   if (__builtin_expect (pid < 0, 0))
 137     pid = -pid;
 138 #endif
 139
 140   /* Safety check.  It would be possible to call this function for
 141      other signals and send a signal from another process.  This is not
 142      correct and might even be a security problem.  Try to catch as
 143      many incorrect invocations as possible.  */
 144   if (sig != SIGCANCEL
 145 #ifdef __ASSUME_CORRECT_SI_PID
 146       /* Kernels before 2.5.75 stored the thread ID and not the process
 147          ID in si_pid so we skip this test.  */
 148       || si->si_pid != pid
 149 #endif
 150       || si->si_code != SI_TKILL)
 151     return;
 152
 153   struct pthread *self = THREAD_SELF;
 154
 155   int oldval = THREAD_GETMEM (self, cancelhandling);
 156   while (1)
 157     {
 158       /* We are canceled now.  When canceled by another thread this flag
 159          is already set but if the signal is directly send (internally or
 160          from another process) is has to be done here.  */
 161       int newval = oldval | CANCELING_BITMASK | CANCELED_BITMASK;
 162
 163       if (oldval == newval || (oldval & EXITING_BITMASK) != 0)
 164         /* Already canceled or exiting.  */
 165         break;
 166
 167       int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
 168                                               oldval);
 169       if (curval == oldval)
 170         {
 171           /* Set the return value.  */
 172           THREAD_SETMEM (self, result, PTHREAD_CANCELED);
 173
 174           /* Make sure asynchronous cancellation is still enabled.  */
 175           if ((newval & CANCELTYPE_BITMASK) != 0)
 176             /* Run the registered destructors and terminate the thread.  */
 177             __do_cancel ();
 178
 179           break;
 180         }
 181
 182       oldval = curval;
 183     }
 184 }
 185
 186
 187 struct xid_command *__xidcmd attribute_hidden;
 188
 189 /* For asynchronous cancellation we use a signal.  This is the handler.  */
 190 static void
 191 sighandler_setxid (int sig, siginfo_t *si, void *ctx)
 192 {
 193 #ifdef __ASSUME_CORRECT_SI_PID
 194   /* Determine the process ID.  It might be negative if the thread is
 195      in the middle of a fork() call.  */
 196   pid_t pid = THREAD_GETMEM (THREAD_SELF, pid);
 197   if (__builtin_expect (pid < 0, 0))
 198     pid = -pid;
 199 #endif
 200
 201   /* Safety check.  It would be possible to call this function for
 202      other signals and send a signal from another process.  This is not
 203      correct and might even be a security problem.  Try to catch as
 204      many incorrect invocations as possible.  */
 205   if (sig != SIGSETXID
 206 #ifdef __ASSUME_CORRECT_SI_PID
 207       /* Kernels before 2.5.75 stored the thread ID and not the process
 208          ID in si_pid so we skip this test.  */
 209       || si->si_pid != pid
 210 #endif
 211       || si->si_code != SI_TKILL)
 212     return;
 213
 214   INTERNAL_SYSCALL_DECL (err);
 215   INTERNAL_SYSCALL_NCS (__xidcmd->syscall_no, err, 3, __xidcmd->id[0],
 216                         __xidcmd->id[1], __xidcmd->id[2]);
 217
 218   if (atomic_decrement_val (&__xidcmd->cntr) == 0)
 219     lll_private_futex_wake (&__xidcmd->cntr, 1);
 220
 221   /* Reset the SETXID flag.  */
 222   struct pthread *self = THREAD_SELF;
 223   int flags = THREAD_GETMEM (self, cancelhandling);
 224   THREAD_SETMEM (self, cancelhandling, flags & ~SETXID_BITMASK);
 225
 226   /* And release the futex.  */
 227   self->setxid_futex = 1;
 228   lll_private_futex_wake (&self->setxid_futex, 1);
 229 }
 230
 231
 232 /* When using __thread for this, we do it in libc so as not
 233    to give libpthread its own TLS segment just for this.  */
 234 extern void **__libc_dl_error_tsd (void) __attribute__ ((const));
 235
 236
 237 /* This can be set by the debugger before initialization is complete.  */
 238 static bool __nptl_initial_report_events;
 239
 240 void
 241 __pthread_initialize_minimal_internal (void)
 242 {
 243 #ifndef SHARED
 244   /* Unlike in the dynamically linked case the dynamic linker has not
 245      taken care of initializing the TLS data structures.  */
 246   __libc_setup_tls (TLS_TCB_SIZE, TLS_TCB_ALIGN);
 247
 248   /* We must prevent gcc from being clever and move any of the
 249      following code ahead of the __libc_setup_tls call.  This function
 250      will initialize the thread register which is subsequently
 251      used.  */
 252   __asm __volatile ("");
 253 #endif
 254
 255   /* Minimal initialization of the thread descriptor.  */
 256   struct pthread *pd = THREAD_SELF;
 257   INTERNAL_SYSCALL_DECL (err);
 258   pd->pid = pd->tid = INTERNAL_SYSCALL (set_tid_address, err, 1, &pd->tid);
 259   THREAD_SETMEM (pd, specific[0], &pd->specific_1stblock[0]);
 260   THREAD_SETMEM (pd, user_stack, true);
 261   if (LLL_LOCK_INITIALIZER != 0)
 262     THREAD_SETMEM (pd, lock, LLL_LOCK_INITIALIZER);
 263 #if HP_TIMING_AVAIL
 264   THREAD_SETMEM (pd, cpuclock_offset, GL(dl_cpuclock_offset));
 265 #endif
 266
 267   /* Initialize the robust mutex data.  */
 268 #ifdef __PTHREAD_MUTEX_HAVE_PREV
 269   pd->robust_prev = &pd->robust_head;
 270 #endif
 271   pd->robust_head.list = &pd->robust_head;
 272 #ifdef __NR_set_robust_list
 273   pd->robust_head.futex_offset = (offsetof (pthread_mutex_t, __data.__lock)
 274                                   - offsetof (pthread_mutex_t,
 275                                               __data.__list.__next));
 276   int res = INTERNAL_SYSCALL (set_robust_list, err, 2, &pd->robust_head,
 277                               sizeof (struct robust_list_head));
 278   if (INTERNAL_SYSCALL_ERROR_P (res, err))
 279 #endif
 280     set_robust_list_not_avail ();
 281
 282 #ifndef __ASSUME_PRIVATE_FUTEX
 283   /* Private futexes are always used (at least internally) so that
 284      doing the test once this early is beneficial.  */
 285   {
 286     int word;
 287     word = INTERNAL_SYSCALL (futex, err, 3, &word,
 288                             FUTEX_WAKE | FUTEX_PRIVATE_FLAG, 1);
 289     if (!INTERNAL_SYSCALL_ERROR_P (word, err))
 290       THREAD_SETMEM (pd, header.private_futex, FUTEX_PRIVATE_FLAG);
 291   }
 292 #endif
 293
 294   /* Set initial thread's stack block from 0 up to __libc_stack_end.
 295      It will be bigger than it actually is, but for unwind.c/pt-longjmp.c
 296      purposes this is good enough.  */
 297   THREAD_SETMEM (pd, stackblock_size, (size_t) __libc_stack_end);
 298
 299   /* Initialize the list of all running threads with the main thread.  */
 300   INIT_LIST_HEAD (&__stack_user);
 301   list_add (&pd->list, &__stack_user);
 302
 303   /* Before initializing __stack_user, the debugger could not find us and
 304      had to set __nptl_initial_report_events.  Propagate its setting.  */
 305   THREAD_SETMEM (pd, report_events, __nptl_initial_report_events);
 306
 307   /* Install the cancellation signal handler.  If for some reason we
 308      cannot install the handler we do not abort.  Maybe we should, but
 309      it is only asynchronous cancellation which is affected.  */
 310   struct sigaction sa;
 311   sa.sa_sigaction = sigcancel_handler;
 312   sa.sa_flags = SA_SIGINFO;
 313   __sigemptyset (&sa.sa_mask);
 314
 315   (void) __libc_sigaction (SIGCANCEL, &sa, NULL);
 316
 317   /* Install the handle to change the threads' uid/gid.  */
 318   sa.sa_sigaction = sighandler_setxid;
 319   sa.sa_flags = SA_SIGINFO | SA_RESTART;
 320
 321   (void) __libc_sigaction (SIGSETXID, &sa, NULL);
 322
 323   /* The parent process might have left the signals blocked.  Just in
 324      case, unblock it.  We reuse the signal mask in the sigaction
 325      structure.  It is already cleared.  */
 326   __sigaddset (&sa.sa_mask, SIGCANCEL);
 327   __sigaddset (&sa.sa_mask, SIGSETXID);
 328   (void) INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_UNBLOCK, &sa.sa_mask,
 329                            NULL, _NSIG / 8);
 330
 331   /* Get the size of the static and alignment requirements for the TLS
 332      block.  */
 333   size_t static_tls_align;
 334   _dl_get_tls_static_info (&__static_tls_size, &static_tls_align);
 335
 336   /* Make sure the size takes all the alignments into account.  */
 337   if (STACK_ALIGN > static_tls_align)
 338     static_tls_align = STACK_ALIGN;
 339   __static_tls_align_m1 = static_tls_align - 1;
 340
 341   __static_tls_size = roundup (__static_tls_size, static_tls_align);
 342
 343   /* Determine the default allowed stack size.  This is the size used
 344      in case the user does not specify one.  */
 345   struct rlimit limit;
 346   if (getrlimit (RLIMIT_STACK, &limit) != 0
 347       || limit.rlim_cur == RLIM_INFINITY)
 348     /* The system limit is not usable.  Use an architecture-specific
 349        default.  */
 350     limit.rlim_cur = ARCH_STACK_DEFAULT_SIZE;
 351   else if (limit.rlim_cur < PTHREAD_STACK_MIN)
 352     /* The system limit is unusably small.
 353        Use the minimal size acceptable.  */
 354     limit.rlim_cur = PTHREAD_STACK_MIN;
 355
 356   /* Make sure it meets the minimum size that allocate_stack
 357      (allocatestack.c) will demand, which depends on the page size.  */
 358   const uintptr_t pagesz = __sysconf (_SC_PAGESIZE);
 359   const size_t minstack = pagesz + __static_tls_size + MINIMAL_REST_STACK;
 360   if (limit.rlim_cur < minstack)
 361     limit.rlim_cur = minstack;
 362
 363   /* Round the resource limit up to page size.  */
 364   limit.rlim_cur = (limit.rlim_cur + pagesz - 1) & -pagesz;
 365   __default_stacksize = limit.rlim_cur;
 366
 367 #ifdef SHARED
 368   /* Transfer the old value from the dynamic linker's internal location.  */
 369   *__libc_dl_error_tsd () = *(*GL(dl_error_catch_tsd)) ();
 370   GL(dl_error_catch_tsd) = &__libc_dl_error_tsd;
 371
 372   /* Make __rtld_lock_{,un}lock_recursive use pthread_mutex_{,un}lock,
 373      keep the lock count from the ld.so implementation.  */
 374   GL(dl_rtld_lock_recursive) = (void *) INTUSE (__pthread_mutex_lock);
 375   GL(dl_rtld_unlock_recursive) = (void *) INTUSE (__pthread_mutex_unlock);
 376   unsigned int rtld_lock_count = GL(dl_load_lock).mutex.__data.__count;
 377   GL(dl_load_lock).mutex.__data.__count = 0;
 378   while (rtld_lock_count-- > 0)
 379     INTUSE (__pthread_mutex_lock) (&GL(dl_load_lock).mutex);
 380
 381   GL(dl_make_stack_executable_hook) = &__make_stacks_executable;
 382 #endif
 383
 384   GL(dl_init_static_tls) = &__pthread_init_static_tls;
 385
 386   GL(dl_wait_lookup_done) = &__wait_lookup_done;
 387
 388   /* Register the fork generation counter with the libc.  */
 389 #ifndef TLS_MULTIPLE_THREADS_IN_TCB
 390   __libc_multiple_threads_ptr =
 391 #endif
 392     __libc_pthread_init (&__fork_generation, __reclaim_stacks,
 393                          ptr_pthread_functions);
 394
 395   /* Determine whether the machine is SMP or not.  */
 396   __is_smp = is_smp_system ();
 397 }
 398 strong_alias (__pthread_initialize_minimal_internal,
 399               __pthread_initialize_minimal)