fbtl/nptl-init.c

   1 /* Copyright (C) 2002-2013 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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <assert.h>
  20 #include <errno.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 <list.h>
  32 #include <fork.h>
  33 #include <version.h>
  34 #include <shlib-compat.h>
  35 #include <smp.h>
  36 #include <lowlevellock.h>
  37 #include <kernel-features.h>
  38 #include <libc-internal.h>
  39
  40 /* Size and alignment of static TLS block.  */
  41 size_t __static_tls_size;
  42 size_t __static_tls_align_m1;
  43
  44 #warning TODO whole file
  45 #if 1
  46 # define set_robust_list_not_avail() do { } while (0)
  47 #else
  48 #ifndef __ASSUME_SET_ROBUST_LIST
  49 /* Negative if we do not have the system call and we can use it.  */
  50 int __set_robust_list_avail;
  51 # define set_robust_list_not_avail() \
  52   __set_robust_list_avail = -1
  53 #else
  54 # define set_robust_list_not_avail() do { } while (0)
  55 #endif
  56
  57 #ifndef __ASSUME_FUTEX_CLOCK_REALTIME
  58 /* Nonzero if we do not have FUTEX_CLOCK_REALTIME.  */
  59 int __have_futex_clock_realtime;
  60 # define __set_futex_clock_realtime() \
  61   __have_futex_clock_realtime = 1
  62 #else
  63 #define __set_futex_clock_realtime() do { } while (0)
  64 #endif
  65 #endif
  66
  67 /* Version of the library, used in libthread_db to detect mismatches.  */
  68 static const char nptl_version[] __attribute_used__ = VERSION;
  69
  70
  71 #ifdef SHARED
  72 static
  73 #else
  74 extern
  75 #endif
  76 void __nptl_set_robust (struct pthread *);
  77
  78 #ifdef SHARED
  79 static void nptl_freeres (void);
  80
  81
  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 = __pthread_mutex_destroy,
 120     .ptr_pthread_mutex_init = __pthread_mutex_init,
 121     .ptr_pthread_mutex_lock = __pthread_mutex_lock,
 122     .ptr_pthread_mutex_unlock = __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,
 128     .ptr___pthread_rwlock_rdlock = __pthread_rwlock_rdlock,
 129     .ptr___pthread_rwlock_wrlock = __pthread_rwlock_wrlock,
 130     .ptr___pthread_rwlock_unlock = __pthread_rwlock_unlock,
 131     .ptr___pthread_key_create = __pthread_key_create,
 132     .ptr___pthread_getspecific = __pthread_getspecific,
 133     .ptr___pthread_setspecific = __pthread_setspecific,
 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 = nptl_freeres,
 142     .ptr_set_robust = __nptl_set_robust
 143   };
 144 # define ptr_pthread_functions &pthread_functions
 145 #else
 146 # define ptr_pthread_functions NULL
 147 #endif
 148
 149
 150 #ifdef SHARED
 151 /* This function is called indirectly from the freeres code in libc.  */
 152 static void
 153 __libc_freeres_fn_section
 154 nptl_freeres (void)
 155 {
 156   __unwind_freeres ();
 157   __free_stacks (0);
 158 }
 159
 160
 161 static
 162 #endif
 163 void
 164 __nptl_set_robust (struct pthread *self)
 165 {
 166 #if 0
 167   INTERNAL_SYSCALL_DECL (err);
 168   INTERNAL_SYSCALL (set_robust_list, err, 2, &self->robust_head,
 169                     sizeof (struct robust_list_head));
 170 #endif
 171 }
 172
 173
 174 /* For asynchronous cancellation we use a signal.  This is the handler.  */
 175 static void
 176 sigcancel_handler (int sig, siginfo_t *si, void *ctx)
 177 {
 178   /* Safety check.  It would be possible to call this function for
 179      other signals and send a signal from another process.  This is not
 180      correct and might even be a security problem.  Try to catch as
 181      many incorrect invocations as possible.  */
 182   if (sig != SIGCANCEL
 183       || si->si_pid != __getpid()
 184 #if 1
 185    )
 186 #else
 187       || si->si_code != SI_TKILL)
 188 #endif
 189     return;
 190
 191   struct pthread *self = THREAD_SELF;
 192
 193   int oldval = THREAD_GETMEM (self, cancelhandling);
 194   while (1)
 195     {
 196       /* We are canceled now.  When canceled by another thread this flag
 197          is already set but if the signal is directly send (internally or
 198          from another process) is has to be done here.  */
 199       int newval = oldval | CANCELING_BITMASK | CANCELED_BITMASK;
 200
 201       if (oldval == newval || (oldval & EXITING_BITMASK) != 0)
 202         /* Already canceled or exiting.  */
 203         break;
 204
 205       int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
 206                                               oldval);
 207       if (curval == oldval)
 208         {
 209           /* Set the return value.  */
 210           THREAD_SETMEM (self, result, PTHREAD_CANCELED);
 211
 212           /* Make sure asynchronous cancellation is still enabled.  */
 213           if ((newval & CANCELTYPE_BITMASK) != 0)
 214             /* Run the registered destructors and terminate the thread.  */
 215             __do_cancel ();
 216
 217           break;
 218         }
 219
 220       oldval = curval;
 221     }
 222 }
 223
 224
 225 struct xid_command *__xidcmd attribute_hidden;
 226
 227 /* We use the SIGSETXID signal in the setuid, setgid, etc. implementations to
 228    tell each thread to call the respective setxid syscall on itself.  This is
 229    the handler.  */
 230 static void
 231 sighandler_setxid (int sig, siginfo_t *si, void *ctx)
 232 {
 233 #if 0
 234   /* Safety check.  It would be possible to call this function for
 235      other signals and send a signal from another process.  This is not
 236      correct and might even be a security problem.  Try to catch as
 237      many incorrect invocations as possible.  */
 238   if (sig != SIGSETXID
 239       || si->si_pid != pid
 240       || si->si_code != SI_TKILL)
 241     return;
 242   INTERNAL_SYSCALL_DECL (err);
 243   INTERNAL_SYSCALL_NCS (__xidcmd->syscall_no, err, 3, __xidcmd->id[0],
 244                         __xidcmd->id[1], __xidcmd->id[2]);
 245 #endif
 246   /* Reset the SETXID flag.  */
 247   struct pthread *self = THREAD_SELF;
 248   int flags, newval;
 249   do
 250     {
 251       flags = THREAD_GETMEM (self, cancelhandling);
 252       newval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling,
 253                                           flags & ~SETXID_BITMASK, flags);
 254     }
 255   while (flags != newval);
 256
 257   /* And release the futex.  */
 258   self->setxid_futex = 1;
 259   lll_futex_wake (&self->setxid_futex, 1, LLL_PRIVATE);
 260
 261   if (atomic_decrement_val (&__xidcmd->cntr) == 0)
 262     lll_futex_wake ((unsigned int *)&__xidcmd->cntr, 1, LLL_PRIVATE);
 263 }
 264
 265
 266 /* When using __thread for this, we do it in libc so as not
 267    to give libpthread its own TLS segment just for this.  */
 268 extern void **__libc_dl_error_tsd (void) __attribute__ ((const));
 269
 270
 271 /* This can be set by the debugger before initialization is complete.  */
 272 static bool __nptl_initial_report_events __attribute_used__;
 273
 274 void
 275 __pthread_initialize_minimal_internal (void)
 276 {
 277   /* Minimal initialization of the thread descriptor.  */
 278   struct pthread *pd = THREAD_SELF;
 279 #if 1
 280   INLINE_SYSCALL(thr_self, 1, &(pd->ktid));
 281 #else
 282   INTERNAL_SYSCALL_DECL (err);
 283   pd->tid = INTERNAL_SYSCALL (set_tid_address, err, 1, &pd->tid);
 284 #endif
 285   THREAD_SETMEM (pd, specific[0], &pd->specific_1stblock[0]);
 286   THREAD_SETMEM (pd, user_stack, true);
 287   if (LLL_LOCK_INITIALIZER != 0)
 288     THREAD_SETMEM (pd, lock, LLL_LOCK_INITIALIZER);
 289 #if HP_TIMING_AVAIL
 290   THREAD_SETMEM (pd, cpuclock_offset, GL(dl_cpuclock_offset));
 291 #endif
 292
 293   /* Initialize the robust mutex data.  */
 294 #ifdef __PTHREAD_MUTEX_HAVE_PREV
 295   pd->robust_prev = &pd->robust_head;
 296 #endif
 297   pd->robust_head.list = &pd->robust_head;
 298 #ifdef __NR_set_robust_list
 299   pd->robust_head.futex_offset = (offsetof (pthread_mutex_t, __data.__lock)
 300                                   - offsetof (pthread_mutex_t,
 301                                               __data.__list.__next));
 302   int res = INTERNAL_SYSCALL (set_robust_list, err, 2, &pd->robust_head,
 303                               sizeof (struct robust_list_head));
 304   if (INTERNAL_SYSCALL_ERROR_P (res, err))
 305 #endif
 306     set_robust_list_not_avail ();
 307
 308 #if 0
 309 #ifndef __ASSUME_PRIVATE_FUTEX
 310   /* Private futexes are always used (at least internally) so that
 311      doing the test once this early is beneficial.  */
 312   {
 313     int word = 0;
 314     word = INTERNAL_SYSCALL (futex, err, 3, &word,
 315                             FUTEX_WAKE | FUTEX_PRIVATE_FLAG, 1);
 316     if (!INTERNAL_SYSCALL_ERROR_P (word, err))
 317       THREAD_SETMEM (pd, header.private_futex, FUTEX_PRIVATE_FLAG);
 318   }
 319
 320   /* Private futexes have been introduced earlier than the
 321      FUTEX_CLOCK_REALTIME flag.  We don't have to run the test if we
 322      know the former are not supported.  This also means we know the
 323      kernel will return ENOSYS for unknown operations.  */
 324   if (THREAD_GETMEM (pd, header.private_futex) != 0)
 325 #endif
 326 #ifndef __ASSUME_FUTEX_CLOCK_REALTIME
 327     {
 328       int word = 0;
 329       /* NB: the syscall actually takes six parameters.  The last is the
 330          bit mask.  But since we will not actually wait at all the value
 331          is irrelevant.  Given that passing six parameters is difficult
 332          on some architectures we just pass whatever random value the
 333          calling convention calls for to the kernel.  It causes no harm.  */
 334       word = INTERNAL_SYSCALL (futex, err, 5, &word,
 335                                FUTEX_WAIT_BITSET | FUTEX_CLOCK_REALTIME
 336                                | FUTEX_PRIVATE_FLAG, 1, NULL, 0);
 337       assert (INTERNAL_SYSCALL_ERROR_P (word, err));
 338       if (INTERNAL_SYSCALL_ERRNO (word, err) != ENOSYS)
 339         __set_futex_clock_realtime ();
 340     }
 341 #endif
 342 #endif
 343   /* Set initial thread's stack block from 0 up to __libc_stack_end.
 344      It will be bigger than it actually is, but for unwind.c/pt-longjmp.c
 345      purposes this is good enough.  */
 346   THREAD_SETMEM (pd, stackblock_size, (size_t) __libc_stack_end);
 347
 348   /* Initialize the list of all running threads with the main thread.  */
 349   INIT_LIST_HEAD (&__stack_user);
 350   list_add (&pd->list, &__stack_user);
 351
 352   /* Before initializing __stack_user, the debugger could not find us and
 353      had to set __nptl_initial_report_events.  Propagate its setting.  */
 354   THREAD_SETMEM (pd, report_events, __nptl_initial_report_events);
 355
 356   /* Install the cancellation signal handler.  If for some reason we
 357      cannot install the handler we do not abort.  Maybe we should, but
 358      it is only asynchronous cancellation which is affected.  */
 359   struct sigaction sa;
 360   sa.sa_sigaction = sigcancel_handler;
 361   sa.sa_flags = SA_SIGINFO;
 362   __sigemptyset (&sa.sa_mask);
 363
 364   (void) __libc_sigaction (SIGCANCEL, &sa, NULL);
 365
 366   /* Install the handle to change the threads' uid/gid.  */
 367   sa.sa_sigaction = sighandler_setxid;
 368   sa.sa_flags = SA_SIGINFO | SA_RESTART;
 369
 370   (void) __libc_sigaction (SIGSETXID, &sa, NULL);
 371
 372   /* The parent process might have left the signals blocked.  Just in
 373      case, unblock it.  We reuse the signal mask in the sigaction
 374      structure.  It is already cleared.  */
 375   __sigaddset (&sa.sa_mask, SIGCANCEL);
 376   __sigaddset (&sa.sa_mask, SIGSETXID);
 377   INLINE_SYSCALL (sigprocmask, 3, SIG_UNBLOCK, &sa.sa_mask, NULL);
 378
 379   /* Get the size of the static and alignment requirements for the TLS
 380      block.  */
 381   size_t static_tls_align;
 382   _dl_get_tls_static_info (&__static_tls_size, &static_tls_align);
 383
 384   /* Make sure the size takes all the alignments into account.  */
 385   if (STACK_ALIGN > static_tls_align)
 386     static_tls_align = STACK_ALIGN;
 387   __static_tls_align_m1 = static_tls_align - 1;
 388
 389   __static_tls_size = roundup (__static_tls_size, static_tls_align);
 390
 391   /* Determine the default allowed stack size.  This is the size used
 392      in case the user does not specify one.  */
 393   struct rlimit limit;
 394   if (__getrlimit (RLIMIT_STACK, &limit) != 0
 395       || limit.rlim_cur == RLIM_INFINITY)
 396     /* The system limit is not usable.  Use an architecture-specific
 397        default.  */
 398     limit.rlim_cur = ARCH_STACK_DEFAULT_SIZE;
 399   else if (limit.rlim_cur < PTHREAD_STACK_MIN)
 400     /* The system limit is unusably small.
 401        Use the minimal size acceptable.  */
 402     limit.rlim_cur = PTHREAD_STACK_MIN;
 403   else if (limit.rlim_cur > (4 * ARCH_STACK_DEFAULT_SIZE))
 404     /* The system limit is unusably high.
 405        Use the maximal size acceptable.  */
 406     limit.rlim_cur = (4 * ARCH_STACK_DEFAULT_SIZE);
 407
 408   /* Make sure it meets the minimum size that allocate_stack
 409      (allocatestack.c) will demand, which depends on the page size.  */
 410   const uintptr_t pagesz = GLRO(dl_pagesize);
 411   const size_t minstack = pagesz + __static_tls_size + MINIMAL_REST_STACK;
 412   if (limit.rlim_cur < minstack)
 413     limit.rlim_cur = minstack;
 414
 415   /* Round the resource limit up to page size.  */
 416   limit.rlim_cur = ALIGN_UP (limit.rlim_cur, pagesz);
 417   lll_lock (__default_pthread_attr_lock, LLL_PRIVATE);
 418   __default_pthread_attr.stacksize = limit.rlim_cur;
 419   __default_pthread_attr.guardsize = GLRO (dl_pagesize);
 420   lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE);
 421
 422 #ifdef SHARED
 423   /* Make __rtld_lock_{,un}lock_recursive use pthread_mutex_{,un}lock,
 424      keep the lock count from the ld.so implementation.  */
 425   GL(dl_rtld_lock_recursive) = (void *) __pthread_mutex_lock;
 426   GL(dl_rtld_unlock_recursive) = (void *) __pthread_mutex_unlock;
 427   unsigned int rtld_lock_count = GL(dl_load_lock).mutex.__data.__count;
 428   GL(dl_load_lock).mutex.__data.__count = 0;
 429   while (rtld_lock_count-- > 0)
 430     __pthread_mutex_lock (&GL(dl_load_lock).mutex);
 431
 432   GL(dl_make_stack_executable_hook) = &__make_stacks_executable;
 433 #endif
 434
 435   GL(dl_init_static_tls) = &__pthread_init_static_tls;
 436
 437   GL(dl_wait_lookup_done) = &__wait_lookup_done;
 438
 439   /* Register the fork generation counter with the libc.  */
 440 #ifndef TLS_MULTIPLE_THREADS_IN_TCB
 441   __libc_multiple_threads_ptr =
 442 #endif
 443     __libc_pthread_init (&__fork_generation, __reclaim_stacks,
 444                          ptr_pthread_functions);
 445
 446   /* Determine whether the machine is SMP or not.  */
 447   __is_smp = is_smp_system ();
 448 }
 449 strong_alias (__pthread_initialize_minimal_internal,
 450               __pthread_initialize_minimal)
 451
 452
 453 size_t
 454 __pthread_get_minstack (const pthread_attr_t *attr)
 455 {
 456   struct pthread_attr *iattr = (struct pthread_attr *) attr;
 457
 458   return (GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN
 459           + iattr->guardsize);
 460 }