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