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 #ifndef 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     /* For now only the stack cache needs to be freed.  */
 141     .ptr_freeres = __free_stack_cache
 142   };
 143 # define ptr_pthread_functions &pthread_functions
 144 #else
 145 # define ptr_pthread_functions NULL
 146 #endif
 147
 148
 149 /* For asynchronous cancellation we use a signal.  This is the handler.  */
 150 static void
 151 sigcancel_handler (int sig, siginfo_t *si, void *ctx)
 152 {
 153 #ifdef __ASSUME_CORRECT_SI_PID
 154   /* Determine the process ID.  It might be negative if the thread is
 155      in the middle of a fork() call.  */
 156   pid_t pid = THREAD_GETMEM (THREAD_SELF, pid);
 157   if (__builtin_expect (pid < 0, 0))
 158     pid = -pid;
 159 #endif
 160
 161   /* Safety check.  It would be possible to call this function for
 162      other signals and send a signal from another process.  This is not
 163      correct and might even be a security problem.  Try to catch as
 164      many incorrect invocations as possible.  */
 165   if (sig != SIGCANCEL
 166 #ifdef __ASSUME_CORRECT_SI_PID
 167       /* Kernels before 2.5.75 stored the thread ID and not the process
 168          ID in si_pid so we skip this test.  */
 169       || si->si_pid != pid
 170 #endif
 171       || si->si_code != SI_TKILL)
 172     return;
 173
 174   struct pthread *self = THREAD_SELF;
 175
 176   int oldval = THREAD_GETMEM (self, cancelhandling);
 177   while (1)
 178     {
 179       /* We are canceled now.  When canceled by another thread this flag
 180          is already set but if the signal is directly send (internally or
 181          from another process) is has to be done here.  */
 182       int newval = oldval | CANCELING_BITMASK | CANCELED_BITMASK;
 183
 184       if (oldval == newval || (oldval & EXITING_BITMASK) != 0)
 185         /* Already canceled or exiting.  */
 186         break;
 187
 188       int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
 189                                               oldval);
 190       if (curval == oldval)
 191         {
 192           /* Set the return value.  */
 193           THREAD_SETMEM (self, result, PTHREAD_CANCELED);
 194
 195           /* Make sure asynchronous cancellation is still enabled.  */
 196           if ((newval & CANCELTYPE_BITMASK) != 0)
 197             /* Run the registered destructors and terminate the thread.  */
 198             __do_cancel ();
 199
 200           break;
 201         }
 202
 203       oldval = curval;
 204     }
 205 }
 206
 207
 208 struct xid_command *__xidcmd attribute_hidden;
 209
 210 /* For asynchronous cancellation we use a signal.  This is the handler.  */
 211 static void
 212 sighandler_setxid (int sig, siginfo_t *si, void *ctx)
 213 {
 214 #ifdef __ASSUME_CORRECT_SI_PID
 215   /* Determine the process ID.  It might be negative if the thread is
 216      in the middle of a fork() call.  */
 217   pid_t pid = THREAD_GETMEM (THREAD_SELF, pid);
 218   if (__builtin_expect (pid < 0, 0))
 219     pid = -pid;
 220 #endif
 221
 222   /* Safety check.  It would be possible to call this function for
 223      other signals and send a signal from another process.  This is not
 224      correct and might even be a security problem.  Try to catch as
 225      many incorrect invocations as possible.  */
 226   if (sig != SIGSETXID
 227 #ifdef __ASSUME_CORRECT_SI_PID
 228       /* Kernels before 2.5.75 stored the thread ID and not the process
 229          ID in si_pid so we skip this test.  */
 230       || si->si_pid != pid
 231 #endif
 232       || si->si_code != SI_TKILL)
 233     return;
 234
 235   INTERNAL_SYSCALL_DECL (err);
 236   INTERNAL_SYSCALL_NCS (__xidcmd->syscall_no, err, 3, __xidcmd->id[0],
 237                         __xidcmd->id[1], __xidcmd->id[2]);
 238
 239   if (atomic_decrement_val (&__xidcmd->cntr) == 0)
 240     lll_futex_wake (&__xidcmd->cntr, 1);
 241
 242   /* Reset the SETXID flag.  */
 243   struct pthread *self = THREAD_SELF;
 244   int flags = THREAD_GETMEM (self, cancelhandling);
 245   THREAD_SETMEM (self, cancelhandling, flags & ~SETXID_BITMASK);
 246
 247   /* And release the futex.  */
 248   self->setxid_futex = 1;
 249   lll_futex_wake (&self->setxid_futex, 1);
 250 }
 251
 252
 253 /* When using __thread for this, we do it in libc so as not
 254    to give libpthread its own TLS segment just for this.  */
 255 extern void **__libc_dl_error_tsd (void) __attribute__ ((const));
 256
 257
 258 void
 259 __pthread_initialize_minimal_internal (void)
 260 {
 261 #ifndef SHARED
 262   /* Unlike in the dynamically linked case the dynamic linker has not
 263      taken care of initializing the TLS data structures.  */
 264   __libc_setup_tls (TLS_TCB_SIZE, TLS_TCB_ALIGN);
 265
 266   /* We must prevent gcc from being clever and move any of the
 267      following code ahead of the __libc_setup_tls call.  This function
 268      will initialize the thread register which is subsequently
 269      used.  */
 270   __asm __volatile ("");
 271 #endif
 272
 273   /* Minimal initialization of the thread descriptor.  */
 274   struct pthread *pd = THREAD_SELF;
 275   INTERNAL_SYSCALL_DECL (err);
 276   pd->pid = pd->tid = INTERNAL_SYSCALL (set_tid_address, err, 1, &pd->tid);
 277   THREAD_SETMEM (pd, specific[0], &pd->specific_1stblock[0]);
 278   THREAD_SETMEM (pd, user_stack, true);
 279   if (LLL_LOCK_INITIALIZER != 0)
 280     THREAD_SETMEM (pd, lock, LLL_LOCK_INITIALIZER);
 281 #if HP_TIMING_AVAIL
 282   THREAD_SETMEM (pd, cpuclock_offset, GL(dl_cpuclock_offset));
 283 #endif
 284
 285   /* Initialize the robust mutex data.  */
 286 #ifdef __PTHREAD_MUTEX_HAVE_PREV
 287   pd->robust_prev = &pd->robust_head;
 288 #endif
 289   pd->robust_head.list = &pd->robust_head;
 290 #ifdef __NR_set_robust_list
 291   pd->robust_head.futex_offset = (offsetof (pthread_mutex_t, __data.__lock)
 292                                   - offsetof (pthread_mutex_t,
 293                                               __data.__list.__next));
 294   int res = INTERNAL_SYSCALL (set_robust_list, err, 2, &pd->robust_head,
 295                               sizeof (struct robust_list_head));
 296   if (INTERNAL_SYSCALL_ERROR_P (res, err))
 297 #endif
 298     set_robust_list_not_avail ();
 299
 300   /* Set initial thread's stack block from 0 up to __libc_stack_end.
 301      It will be bigger than it actually is, but for unwind.c/pt-longjmp.c
 302      purposes this is good enough.  */
 303   THREAD_SETMEM (pd, stackblock_size, (size_t) __libc_stack_end);
 304
 305   /* Initialize the list of all running threads with the main thread.  */
 306   INIT_LIST_HEAD (&__stack_user);
 307   list_add (&pd->list, &__stack_user);
 308
 309
 310   /* Install the cancellation signal handler.  If for some reason we
 311      cannot install the handler we do not abort.  Maybe we should, but
 312      it is only asynchronous cancellation which is affected.  */
 313   struct sigaction sa;
 314   sa.sa_sigaction = sigcancel_handler;
 315   sa.sa_flags = SA_SIGINFO;
 316   __sigemptyset (&sa.sa_mask);
 317
 318   (void) __libc_sigaction (SIGCANCEL, &sa, NULL);
 319
 320   /* Install the handle to change the threads' uid/gid.  */
 321   sa.sa_sigaction = sighandler_setxid;
 322   sa.sa_flags = SA_SIGINFO | SA_RESTART;
 323
 324   (void) __libc_sigaction (SIGSETXID, &sa, NULL);
 325
 326   /* The parent process might have left the signals blocked.  Just in
 327      case, unblock it.  We reuse the signal mask in the sigaction
 328      structure.  It is already cleared.  */
 329   __sigaddset (&sa.sa_mask, SIGCANCEL);
 330   __sigaddset (&sa.sa_mask, SIGSETXID);
 331   (void) INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_UNBLOCK, &sa.sa_mask,
 332                            NULL, _NSIG / 8);
 333
 334   /* Get the size of the static and alignment requirements for the TLS
 335      block.  */
 336   size_t static_tls_align;
 337   _dl_get_tls_static_info (&__static_tls_size, &static_tls_align);
 338
 339   /* Make sure the size takes all the alignments into account.  */
 340   if (STACK_ALIGN > static_tls_align)
 341     static_tls_align = STACK_ALIGN;
 342   __static_tls_align_m1 = static_tls_align - 1;
 343
 344   __static_tls_size = roundup (__static_tls_size, static_tls_align);
 345
 346   /* Determine the default allowed stack size.  This is the size used
 347      in case the user does not specify one.  */
 348   struct rlimit limit;
 349   if (getrlimit (RLIMIT_STACK, &limit) != 0
 350       || limit.rlim_cur == RLIM_INFINITY)
 351     /* The system limit is not usable.  Use an architecture-specific
 352        default.  */
 353     limit.rlim_cur = ARCH_STACK_DEFAULT_SIZE;
 354   else if (limit.rlim_cur < PTHREAD_STACK_MIN)
 355     /* The system limit is unusably small.
 356        Use the minimal size acceptable.  */
 357     limit.rlim_cur = PTHREAD_STACK_MIN;
 358
 359   /* Make sure it meets the minimum size that allocate_stack
 360      (allocatestack.c) will demand, which depends on the page size.  */
 361   const uintptr_t pagesz = __sysconf (_SC_PAGESIZE);
 362   const size_t minstack = pagesz + __static_tls_size + MINIMAL_REST_STACK;
 363   if (limit.rlim_cur < minstack)
 364     limit.rlim_cur = minstack;
 365
 366   /* Round the resource limit up to page size.  */
 367   limit.rlim_cur = (limit.rlim_cur + pagesz - 1) & -pagesz;
 368   __default_stacksize = limit.rlim_cur;
 369
 370 #ifdef SHARED
 371   /* Transfer the old value from the dynamic linker's internal location.  */
 372   *__libc_dl_error_tsd () = *(*GL(dl_error_catch_tsd)) ();
 373   GL(dl_error_catch_tsd) = &__libc_dl_error_tsd;
 374
 375   /* Make __rtld_lock_{,un}lock_recursive use pthread_mutex_{,un}lock,
 376      keep the lock count from the ld.so implementation.  */
 377   GL(dl_rtld_lock_recursive) = (void *) INTUSE (__pthread_mutex_lock);
 378   GL(dl_rtld_unlock_recursive) = (void *) INTUSE (__pthread_mutex_unlock);
 379   unsigned int rtld_lock_count = GL(dl_load_lock).mutex.__data.__count;
 380   GL(dl_load_lock).mutex.__data.__count = 0;
 381   while (rtld_lock_count-- > 0)
 382     INTUSE (__pthread_mutex_lock) (&GL(dl_load_lock).mutex);
 383
 384   GL(dl_make_stack_executable_hook) = &__make_stacks_executable;
 385 #endif
 386
 387   GL(dl_init_static_tls) = &__pthread_init_static_tls;
 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)