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 #ifdef __ASSUME_CORRECT_SI_PID
 152   /* Determine the process ID.  It might be negative if the thread is
 153      in the middle of a fork() call.  */
 154   pid_t pid = THREAD_GETMEM (THREAD_SELF, pid);
 155   if (__builtin_expect (pid < 0, 0))
 156     pid = -pid;
 157 #endif
 158
 159   /* Safety check.  It would be possible to call this function for
 160      other signals and send a signal from another process.  This is not
 161      correct and might even be a security problem.  Try to catch as
 162      many incorrect invocations as possible.  */
 163   if (sig != SIGCANCEL
 164 #ifdef __ASSUME_CORRECT_SI_PID
 165       /* Kernels before 2.5.75 stored the thread ID and not the process
 166          ID in si_pid so we skip this test.  */
 167       || si->si_pid != pid
 168 #endif
 169       || si->si_code != SI_TKILL)
 170     return;
 171
 172   struct pthread *self = THREAD_SELF;
 173
 174   int oldval = THREAD_GETMEM (self, cancelhandling);
 175   while (1)
 176     {
 177       /* We are canceled now.  When canceled by another thread this flag
 178          is already set but if the signal is directly send (internally or
 179          from another process) is has to be done here.  */
 180       int newval = oldval | CANCELING_BITMASK | CANCELED_BITMASK;
 181
 182       if (oldval == newval || (oldval & EXITING_BITMASK) != 0)
 183         /* Already canceled or exiting.  */
 184         break;
 185
 186       int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
 187                                               oldval);
 188       if (curval == oldval)
 189         {
 190           /* Set the return value.  */
 191           THREAD_SETMEM (self, result, PTHREAD_CANCELED);
 192
 193           /* Make sure asynchronous cancellation is still enabled.  */
 194           if ((newval & CANCELTYPE_BITMASK) != 0)
 195             /* Run the registered destructors and terminate the thread.  */
 196             __do_cancel ();
 197
 198           break;
 199         }
 200
 201       oldval = curval;
 202     }
 203 }
 204
 205
 206 struct xid_command *__xidcmd attribute_hidden;
 207
 208 /* For asynchronous cancellation we use a signal.  This is the handler.  */
 209 static void
 210 sighandler_setxid (int sig, siginfo_t *si, void *ctx)
 211 {
 212 #ifdef __ASSUME_CORRECT_SI_PID
 213   /* Determine the process ID.  It might be negative if the thread is
 214      in the middle of a fork() call.  */
 215   pid_t pid = THREAD_GETMEM (THREAD_SELF, pid);
 216   if (__builtin_expect (pid < 0, 0))
 217     pid = -pid;
 218 #endif
 219
 220   /* Safety check.  It would be possible to call this function for
 221      other signals and send a signal from another process.  This is not
 222      correct and might even be a security problem.  Try to catch as
 223      many incorrect invocations as possible.  */
 224   if (sig != SIGSETXID
 225 #ifdef __ASSUME_CORRECT_SI_PID
 226       /* Kernels before 2.5.75 stored the thread ID and not the process
 227          ID in si_pid so we skip this test.  */
 228       || si->si_pid != pid
 229 #endif
 230       || si->si_code != SI_TKILL)
 231     return;
 232
 233   INTERNAL_SYSCALL_DECL (err);
 234   INTERNAL_SYSCALL_NCS (__xidcmd->syscall_no, err, 3, __xidcmd->id[0],
 235                         __xidcmd->id[1], __xidcmd->id[2]);
 236
 237   if (atomic_decrement_val (&__xidcmd->cntr) == 0)
 238     lll_futex_wake (&__xidcmd->cntr, 1);
 239
 240   /* Reset the SETXID flag.  */
 241   struct pthread *self = THREAD_SELF;
 242   int flags = THREAD_GETMEM (self, cancelhandling);
 243   THREAD_SETMEM (self, cancelhandling, flags & ~SETXID_BITMASK);
 244
 245   /* And release the futex.  */
 246   self->setxid_futex = 1;
 247   lll_futex_wake (&self->setxid_futex, 1);
 248 }
 249
 250
 251 /* When using __thread for this, we do it in libc so as not
 252    to give libpthread its own TLS segment just for this.  */
 253 extern void **__libc_dl_error_tsd (void) __attribute__ ((const));
 254
 255
 256 void
 257 __pthread_initialize_minimal_internal (void)
 258 {
 259 #ifndef SHARED
 260   /* Unlike in the dynamically linked case the dynamic linker has not
 261      taken care of initializing the TLS data structures.  */
 262   __libc_setup_tls (TLS_TCB_SIZE, TLS_TCB_ALIGN);
 263
 264   /* We must prevent gcc from being clever and move any of the
 265      following code ahead of the __libc_setup_tls call.  This function
 266      will initialize the thread register which is subsequently
 267      used.  */
 268   __asm __volatile ("");
 269 #endif
 270
 271   /* Minimal initialization of the thread descriptor.  */
 272   struct pthread *pd = THREAD_SELF;
 273   INTERNAL_SYSCALL_DECL (err);
 274   pd->pid = pd->tid = INTERNAL_SYSCALL (set_tid_address, err, 1, &pd->tid);
 275   THREAD_SETMEM (pd, specific[0], &pd->specific_1stblock[0]);
 276   THREAD_SETMEM (pd, user_stack, true);
 277   if (LLL_LOCK_INITIALIZER != 0)
 278     THREAD_SETMEM (pd, lock, LLL_LOCK_INITIALIZER);
 279 #if HP_TIMING_AVAIL
 280   THREAD_SETMEM (pd, cpuclock_offset, GL(dl_cpuclock_offset));
 281 #endif
 282
 283   /* Initialize the robust mutex data.  */
 284 #ifdef __PTHREAD_MUTEX_HAVE_PREV
 285   pd->robust_prev = &pd->robust_head;
 286 #endif
 287   pd->robust_head.list = &pd->robust_head;
 288 #ifdef __NR_set_robust_list
 289   pd->robust_head.futex_offset = (offsetof (pthread_mutex_t, __data.__lock)
 290                                   - offsetof (pthread_mutex_t,
 291                                               __data.__list.__next));
 292   int res = INTERNAL_SYSCALL (set_robust_list, err, 2, &pd->robust_head,
 293                               sizeof (struct robust_list_head));
 294   if (INTERNAL_SYSCALL_ERROR_P (res, err))
 295 #endif
 296     set_robust_list_not_avail ();
 297
 298   /* Set initial thread's stack block from 0 up to __libc_stack_end.
 299      It will be bigger than it actually is, but for unwind.c/pt-longjmp.c
 300      purposes this is good enough.  */
 301   THREAD_SETMEM (pd, stackblock_size, (size_t) __libc_stack_end);
 302
 303   /* Initialize the list of all running threads with the main thread.  */
 304   INIT_LIST_HEAD (&__stack_user);
 305   list_add (&pd->list, &__stack_user);
 306
 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   /* Register the fork generation counter with the libc.  */
 388 #ifndef TLS_MULTIPLE_THREADS_IN_TCB
 389   __libc_multiple_threads_ptr =
 390 #endif
 391     __libc_pthread_init (&__fork_generation, __reclaim_stacks,
 392                          ptr_pthread_functions);
 393
 394   /* Determine whether the machine is SMP or not.  */
 395   __is_smp = is_smp_system ();
 396 }
 397 strong_alias (__pthread_initialize_minimal_internal,
 398               __pthread_initialize_minimal)