nptl/init.c

   1 /* Copyright (C) 2002, 2003, 2004, 2005, 2006 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 #ifndef __NR_set_tid_address
  39 /* XXX For the time being...  Once we can rely on the kernel headers
  40    having the definition remove these lines.  */
  41 #if defined __s390__
  42 # define __NR_set_tid_address   252
  43 #elif defined __ia64__
  44 # define __NR_set_tid_address   1233
  45 #elif defined __i386__
  46 # define __NR_set_tid_address   258
  47 #elif defined __x86_64__
  48 # define __NR_set_tid_address   218
  49 #elif defined __powerpc__
  50 # define __NR_set_tid_address   232
  51 #elif defined __sparc__
  52 # define __NR_set_tid_address   166
  53 #else
  54 # error "define __NR_set_tid_address"
  55 #endif
  56 #endif
  57
  58
  59 /* Size and alignment of static TLS block.  */
  60 size_t __static_tls_size;
  61 size_t __static_tls_align_m1;
  62
  63 #ifndef __ASSUME_SET_ROBUST_LIST
  64 /* Negative if we do not have the system call and we can use it.  */
  65 int __set_robust_list_avail;
  66 # define set_robust_list_not_avail() \
  67   __set_robust_list_avail = -1
  68 #else
  69 # define set_robust_list_not_avail() do { } while (0)
  70 #endif
  71
  72 /* Version of the library, used in libthread_db to detect mismatches.  */
  73 static const char nptl_version[] __attribute_used__ = VERSION;
  74
  75
  76 #if defined USE_TLS && !defined SHARED
  77 extern void __libc_setup_tls (size_t tcbsize, size_t tcbalign);
  78 #endif
  79
  80
  81 #ifdef SHARED
  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   };
 141 # define ptr_pthread_functions &pthread_functions
 142 #else
 143 # define ptr_pthread_functions NULL
 144 #endif
 145
 146
 147 /* For asynchronous cancellation we use a signal.  This is the handler.  */
 148 static void
 149 sigcancel_handler (int sig, siginfo_t *si, void *ctx)
 150 {
 151   /* Safety check.  It would be possible to call this function for
 152      other signals and send a signal from another process.  This is not
 153      correct and might even be a security problem.  Try to catch as
 154      many incorrect invocations as possible.  */
 155   if (sig != SIGCANCEL
 156 #ifdef __ASSUME_CORRECT_SI_PID
 157       /* Kernels before 2.5.75 stored the thread ID and not the process
 158          ID in si_pid so we skip this test.  */
 159       || si->si_pid != THREAD_GETMEM (THREAD_SELF, pid)
 160 #endif
 161       || si->si_code != SI_TKILL)
 162     return;
 163
 164   struct pthread *self = THREAD_SELF;
 165
 166   int oldval = THREAD_GETMEM (self, cancelhandling);
 167   while (1)
 168     {
 169       /* We are canceled now.  When canceled by another thread this flag
 170          is already set but if the signal is directly send (internally or
 171          from another process) is has to be done here.  */
 172       int newval = oldval | CANCELING_BITMASK | CANCELED_BITMASK;
 173
 174       if (oldval == newval || (oldval & EXITING_BITMASK) != 0)
 175         /* Already canceled or exiting.  */
 176         break;
 177
 178       int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
 179                                               oldval);
 180       if (curval == oldval)
 181         {
 182           /* Set the return value.  */
 183           THREAD_SETMEM (self, result, PTHREAD_CANCELED);
 184
 185           /* Make sure asynchronous cancellation is still enabled.  */
 186           if ((newval & CANCELTYPE_BITMASK) != 0)
 187             /* Run the registered destructors and terminate the thread.  */
 188             __do_cancel ();
 189
 190           break;
 191         }
 192
 193       oldval = curval;
 194     }
 195 }
 196
 197
 198 struct xid_command *__xidcmd attribute_hidden;
 199
 200 /* For asynchronous cancellation we use a signal.  This is the handler.  */
 201 static void
 202 sighandler_setxid (int sig, siginfo_t *si, void *ctx)
 203 {
 204   /* Safety check.  It would be possible to call this function for
 205      other signals and send a signal from another process.  This is not
 206      correct and might even be a security problem.  Try to catch as
 207      many incorrect invocations as possible.  */
 208   if (sig != SIGSETXID
 209 #ifdef __ASSUME_CORRECT_SI_PID
 210       /* Kernels before 2.5.75 stored the thread ID and not the process
 211          ID in si_pid so we skip this test.  */
 212       || si->si_pid != THREAD_GETMEM (THREAD_SELF, pid)
 213 #endif
 214       || si->si_code != SI_TKILL)
 215     return;
 216
 217   INTERNAL_SYSCALL_DECL (err);
 218   INTERNAL_SYSCALL_NCS (__xidcmd->syscall_no, err, 3, __xidcmd->id[0],
 219                         __xidcmd->id[1], __xidcmd->id[2]);
 220
 221   if (atomic_decrement_val (&__xidcmd->cntr) == 0)
 222     lll_futex_wake (&__xidcmd->cntr, 1);
 223
 224   /* Reset the SETXID flag.  */
 225   struct pthread *self = THREAD_SELF;
 226   int flags = THREAD_GETMEM (self, cancelhandling);
 227   THREAD_SETMEM (self, cancelhandling, flags & ~SETXID_BITMASK);
 228
 229   /* And release the futex.  */
 230   self->setxid_futex = 1;
 231   lll_futex_wake (&self->setxid_futex, 1);
 232 }
 233
 234
 235 /* When using __thread for this, we do it in libc so as not
 236    to give libpthread its own TLS segment just for this.  */
 237 extern void **__libc_dl_error_tsd (void) __attribute__ ((const));
 238
 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   /* Set initial thread's stack block from 0 up to __libc_stack_end.
 283      It will be bigger than it actually is, but for unwind.c/pt-longjmp.c
 284      purposes this is good enough.  */
 285   THREAD_SETMEM (pd, stackblock_size, (size_t) __libc_stack_end);
 286
 287   /* Initialize the list of all running threads with the main thread.  */
 288   INIT_LIST_HEAD (&__stack_user);
 289   list_add (&pd->list, &__stack_user);
 290
 291
 292   /* Install the cancellation signal handler.  If for some reason we
 293      cannot install the handler we do not abort.  Maybe we should, but
 294      it is only asynchronous cancellation which is affected.  */
 295   struct sigaction sa;
 296   sa.sa_sigaction = sigcancel_handler;
 297   sa.sa_flags = SA_SIGINFO;
 298   __sigemptyset (&sa.sa_mask);
 299
 300   (void) __libc_sigaction (SIGCANCEL, &sa, NULL);
 301
 302   /* Install the handle to change the threads' uid/gid.  */
 303   sa.sa_sigaction = sighandler_setxid;
 304   sa.sa_flags = SA_SIGINFO | SA_RESTART;
 305
 306   (void) __libc_sigaction (SIGSETXID, &sa, NULL);
 307
 308   /* The parent process might have left the signals blocked.  Just in
 309      case, unblock it.  We reuse the signal mask in the sigaction
 310      structure.  It is already cleared.  */
 311   __sigaddset (&sa.sa_mask, SIGCANCEL);
 312   __sigaddset (&sa.sa_mask, SIGSETXID);
 313   (void) INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_UNBLOCK, &sa.sa_mask,
 314                            NULL, _NSIG / 8);
 315
 316   /* Get the size of the static and alignment requirements for the TLS
 317      block.  */
 318   size_t static_tls_align;
 319   _dl_get_tls_static_info (&__static_tls_size, &static_tls_align);
 320
 321   /* Make sure the size takes all the alignments into account.  */
 322   if (STACK_ALIGN > static_tls_align)
 323     static_tls_align = STACK_ALIGN;
 324   __static_tls_align_m1 = static_tls_align - 1;
 325
 326   __static_tls_size = roundup (__static_tls_size, static_tls_align);
 327
 328   /* Determine the default allowed stack size.  This is the size used
 329      in case the user does not specify one.  */
 330   struct rlimit limit;
 331   if (getrlimit (RLIMIT_STACK, &limit) != 0
 332       || limit.rlim_cur == RLIM_INFINITY)
 333     /* The system limit is not usable.  Use an architecture-specific
 334        default.  */
 335     limit.rlim_cur = ARCH_STACK_DEFAULT_SIZE;
 336   else if (limit.rlim_cur < PTHREAD_STACK_MIN)
 337     /* The system limit is unusably small.
 338        Use the minimal size acceptable.  */
 339     limit.rlim_cur = PTHREAD_STACK_MIN;
 340
 341   /* Make sure it meets the minimum size that allocate_stack
 342      (allocatestack.c) will demand, which depends on the page size.  */
 343   const uintptr_t pagesz = __sysconf (_SC_PAGESIZE);
 344   const size_t minstack = pagesz + __static_tls_size + MINIMAL_REST_STACK;
 345   if (limit.rlim_cur < minstack)
 346     limit.rlim_cur = minstack;
 347
 348   /* Round the resource limit up to page size.  */
 349   limit.rlim_cur = (limit.rlim_cur + pagesz - 1) & -pagesz;
 350   __default_stacksize = limit.rlim_cur;
 351
 352 #ifdef SHARED
 353   /* Transfer the old value from the dynamic linker's internal location.  */
 354   *__libc_dl_error_tsd () = *(*GL(dl_error_catch_tsd)) ();
 355   GL(dl_error_catch_tsd) = &__libc_dl_error_tsd;
 356
 357   /* Make __rtld_lock_{,un}lock_recursive use pthread_mutex_{,un}lock,
 358      keep the lock count from the ld.so implementation.  */
 359   GL(dl_rtld_lock_recursive) = (void *) INTUSE (__pthread_mutex_lock);
 360   GL(dl_rtld_unlock_recursive) = (void *) INTUSE (__pthread_mutex_unlock);
 361   unsigned int rtld_lock_count = GL(dl_load_lock).mutex.__data.__count;
 362   GL(dl_load_lock).mutex.__data.__count = 0;
 363   while (rtld_lock_count-- > 0)
 364     INTUSE (__pthread_mutex_lock) (&GL(dl_load_lock).mutex);
 365
 366   GL(dl_make_stack_executable_hook) = &__make_stacks_executable;
 367 #endif
 368
 369   GL(dl_init_static_tls) = &__pthread_init_static_tls;
 370
 371   /* Register the fork generation counter with the libc.  */
 372 #ifndef TLS_MULTIPLE_THREADS_IN_TCB
 373   __libc_multiple_threads_ptr =
 374 #endif
 375     __libc_pthread_init (&__fork_generation, __reclaim_stacks,
 376                          ptr_pthread_functions);
 377
 378   /* Determine whether the machine is SMP or not.  */
 379   __is_smp = is_smp_system ();
 380 }
 381 strong_alias (__pthread_initialize_minimal_internal,
 382               __pthread_initialize_minimal)