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_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_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 void
 238 __pthread_initialize_minimal_internal (void)
 239 {
 240 #ifndef SHARED
 241   /* Unlike in the dynamically linked case the dynamic linker has not
 242      taken care of initializing the TLS data structures.  */
 243   __libc_setup_tls (TLS_TCB_SIZE, TLS_TCB_ALIGN);
 244
 245   /* We must prevent gcc from being clever and move any of the
 246      following code ahead of the __libc_setup_tls call.  This function
 247      will initialize the thread register which is subsequently
 248      used.  */
 249   __asm __volatile ("");
 250 #endif
 251
 252   /* Minimal initialization of the thread descriptor.  */
 253   struct pthread *pd = THREAD_SELF;
 254   INTERNAL_SYSCALL_DECL (err);
 255   pd->pid = pd->tid = INTERNAL_SYSCALL (set_tid_address, err, 1, &pd->tid);
 256   THREAD_SETMEM (pd, specific[0], &pd->specific_1stblock[0]);
 257   THREAD_SETMEM (pd, user_stack, true);
 258   if (LLL_LOCK_INITIALIZER != 0)
 259     THREAD_SETMEM (pd, lock, LLL_LOCK_INITIALIZER);
 260 #if HP_TIMING_AVAIL
 261   THREAD_SETMEM (pd, cpuclock_offset, GL(dl_cpuclock_offset));
 262 #endif
 263
 264   /* Initialize the robust mutex data.  */
 265 #ifdef __PTHREAD_MUTEX_HAVE_PREV
 266   pd->robust_prev = &pd->robust_head;
 267 #endif
 268   pd->robust_head.list = &pd->robust_head;
 269 #ifdef __NR_set_robust_list
 270   pd->robust_head.futex_offset = (offsetof (pthread_mutex_t, __data.__lock)
 271                                   - offsetof (pthread_mutex_t,
 272                                               __data.__list.__next));
 273   int res = INTERNAL_SYSCALL (set_robust_list, err, 2, &pd->robust_head,
 274                               sizeof (struct robust_list_head));
 275   if (INTERNAL_SYSCALL_ERROR_P (res, err))
 276 #endif
 277     set_robust_list_not_avail ();
 278
 279 #ifndef __ASSUME_PRIVATE_FUTEX
 280   /* Private futexes are always used (at least internally) so that
 281      doing the test once this early is beneficial.  */
 282   {
 283     int word;
 284     word = INTERNAL_SYSCALL (futex, err, 3, &word,
 285                             FUTEX_WAKE | FUTEX_PRIVATE_FLAG, 1);
 286     if (!INTERNAL_SYSCALL_ERROR_P (word, err))
 287       THREAD_SETMEM (pd, header.private_futex, FUTEX_PRIVATE_FLAG);
 288   }
 289 #endif
 290
 291   /* Set initial thread's stack block from 0 up to __libc_stack_end.
 292      It will be bigger than it actually is, but for unwind.c/pt-longjmp.c
 293      purposes this is good enough.  */
 294   THREAD_SETMEM (pd, stackblock_size, (size_t) __libc_stack_end);
 295
 296   /* Initialize the list of all running threads with the main thread.  */
 297   INIT_LIST_HEAD (&__stack_user);
 298   list_add (&pd->list, &__stack_user);
 299
 300
 301   /* Install the cancellation signal handler.  If for some reason we
 302      cannot install the handler we do not abort.  Maybe we should, but
 303      it is only asynchronous cancellation which is affected.  */
 304   struct sigaction sa;
 305   sa.sa_sigaction = sigcancel_handler;
 306   sa.sa_flags = SA_SIGINFO;
 307   __sigemptyset (&sa.sa_mask);
 308
 309   (void) __libc_sigaction (SIGCANCEL, &sa, NULL);
 310
 311   /* Install the handle to change the threads' uid/gid.  */
 312   sa.sa_sigaction = sighandler_setxid;
 313   sa.sa_flags = SA_SIGINFO | SA_RESTART;
 314
 315   (void) __libc_sigaction (SIGSETXID, &sa, NULL);
 316
 317   /* The parent process might have left the signals blocked.  Just in
 318      case, unblock it.  We reuse the signal mask in the sigaction
 319      structure.  It is already cleared.  */
 320   __sigaddset (&sa.sa_mask, SIGCANCEL);
 321   __sigaddset (&sa.sa_mask, SIGSETXID);
 322   (void) INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_UNBLOCK, &sa.sa_mask,
 323                            NULL, _NSIG / 8);
 324
 325   /* Get the size of the static and alignment requirements for the TLS
 326      block.  */
 327   size_t static_tls_align;
 328   _dl_get_tls_static_info (&__static_tls_size, &static_tls_align);
 329
 330   /* Make sure the size takes all the alignments into account.  */
 331   if (STACK_ALIGN > static_tls_align)
 332     static_tls_align = STACK_ALIGN;
 333   __static_tls_align_m1 = static_tls_align - 1;
 334
 335   __static_tls_size = roundup (__static_tls_size, static_tls_align);
 336
 337   /* Determine the default allowed stack size.  This is the size used
 338      in case the user does not specify one.  */
 339   struct rlimit limit;
 340   if (getrlimit (RLIMIT_STACK, &limit) != 0
 341       || limit.rlim_cur == RLIM_INFINITY)
 342     /* The system limit is not usable.  Use an architecture-specific
 343        default.  */
 344     limit.rlim_cur = ARCH_STACK_DEFAULT_SIZE;
 345   else if (limit.rlim_cur < PTHREAD_STACK_MIN)
 346     /* The system limit is unusably small.
 347        Use the minimal size acceptable.  */
 348     limit.rlim_cur = PTHREAD_STACK_MIN;
 349
 350   /* Make sure it meets the minimum size that allocate_stack
 351      (allocatestack.c) will demand, which depends on the page size.  */
 352   const uintptr_t pagesz = __sysconf (_SC_PAGESIZE);
 353   const size_t minstack = pagesz + __static_tls_size + MINIMAL_REST_STACK;
 354   if (limit.rlim_cur < minstack)
 355     limit.rlim_cur = minstack;
 356
 357   /* Round the resource limit up to page size.  */
 358   limit.rlim_cur = (limit.rlim_cur + pagesz - 1) & -pagesz;
 359   __default_stacksize = limit.rlim_cur;
 360
 361 #ifdef SHARED
 362   /* Transfer the old value from the dynamic linker's internal location.  */
 363   *__libc_dl_error_tsd () = *(*GL(dl_error_catch_tsd)) ();
 364   GL(dl_error_catch_tsd) = &__libc_dl_error_tsd;
 365
 366   /* Make __rtld_lock_{,un}lock_recursive use pthread_mutex_{,un}lock,
 367      keep the lock count from the ld.so implementation.  */
 368   GL(dl_rtld_lock_recursive) = (void *) INTUSE (__pthread_mutex_lock);
 369   GL(dl_rtld_unlock_recursive) = (void *) INTUSE (__pthread_mutex_unlock);
 370   unsigned int rtld_lock_count = GL(dl_load_lock).mutex.__data.__count;
 371   GL(dl_load_lock).mutex.__data.__count = 0;
 372   while (rtld_lock_count-- > 0)
 373     INTUSE (__pthread_mutex_lock) (&GL(dl_load_lock).mutex);
 374
 375   GL(dl_make_stack_executable_hook) = &__make_stacks_executable;
 376 #endif
 377
 378   GL(dl_init_static_tls) = &__pthread_init_static_tls;
 379
 380   GL(dl_wait_lookup_done) = &__wait_lookup_done;
 381
 382   /* Register the fork generation counter with the libc.  */
 383 #ifndef TLS_MULTIPLE_THREADS_IN_TCB
 384   __libc_multiple_threads_ptr =
 385 #endif
 386     __libc_pthread_init (&__fork_generation, __reclaim_stacks,
 387                          ptr_pthread_functions);
 388
 389   /* Determine whether the machine is SMP or not.  */
 390   __is_smp = is_smp_system ();
 391 }
 392 strong_alias (__pthread_initialize_minimal_internal,
 393               __pthread_initialize_minimal)