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
  37
  38 /* Size and alignment of static TLS block.  */
  39 size_t __static_tls_size;
  40 size_t __static_tls_align_m1;
  41
  42 #ifndef __ASSUME_SET_ROBUST_LIST
  43 /* Negative if we do not have the system call and we can use it.  */
  44 int __set_robust_list_avail;
  45 # define set_robust_list_not_avail() \
  46   __set_robust_list_avail = -1
  47 #else
  48 # define set_robust_list_not_avail() do { } while (0)
  49 #endif
  50
  51 /* Version of the library, used in libthread_db to detect mismatches.  */
  52 static const char nptl_version[] __attribute_used__ = VERSION;
  53
  54
  55 #ifndef SHARED
  56 extern void __libc_setup_tls (size_t tcbsize, size_t tcbalign);
  57 #endif
  58
  59
  60 #ifdef SHARED
  61 static const struct pthread_functions pthread_functions =
  62   {
  63     .ptr_pthread_attr_destroy = __pthread_attr_destroy,
  64 # if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1)
  65     .ptr___pthread_attr_init_2_0 = __pthread_attr_init_2_0,
  66 # endif
  67     .ptr___pthread_attr_init_2_1 = __pthread_attr_init_2_1,
  68     .ptr_pthread_attr_getdetachstate = __pthread_attr_getdetachstate,
  69     .ptr_pthread_attr_setdetachstate = __pthread_attr_setdetachstate,
  70     .ptr_pthread_attr_getinheritsched = __pthread_attr_getinheritsched,
  71     .ptr_pthread_attr_setinheritsched = __pthread_attr_setinheritsched,
  72     .ptr_pthread_attr_getschedparam = __pthread_attr_getschedparam,
  73     .ptr_pthread_attr_setschedparam = __pthread_attr_setschedparam,
  74     .ptr_pthread_attr_getschedpolicy = __pthread_attr_getschedpolicy,
  75     .ptr_pthread_attr_setschedpolicy = __pthread_attr_setschedpolicy,
  76     .ptr_pthread_attr_getscope = __pthread_attr_getscope,
  77     .ptr_pthread_attr_setscope = __pthread_attr_setscope,
  78     .ptr_pthread_condattr_destroy = __pthread_condattr_destroy,
  79     .ptr_pthread_condattr_init = __pthread_condattr_init,
  80     .ptr___pthread_cond_broadcast = __pthread_cond_broadcast,
  81     .ptr___pthread_cond_destroy = __pthread_cond_destroy,
  82     .ptr___pthread_cond_init = __pthread_cond_init,
  83     .ptr___pthread_cond_signal = __pthread_cond_signal,
  84     .ptr___pthread_cond_wait = __pthread_cond_wait,
  85     .ptr___pthread_cond_timedwait = __pthread_cond_timedwait,
  86 # if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_3_2)
  87     .ptr___pthread_cond_broadcast_2_0 = __pthread_cond_broadcast_2_0,
  88     .ptr___pthread_cond_destroy_2_0 = __pthread_cond_destroy_2_0,
  89     .ptr___pthread_cond_init_2_0 = __pthread_cond_init_2_0,
  90     .ptr___pthread_cond_signal_2_0 = __pthread_cond_signal_2_0,
  91     .ptr___pthread_cond_wait_2_0 = __pthread_cond_wait_2_0,
  92     .ptr___pthread_cond_timedwait_2_0 = __pthread_cond_timedwait_2_0,
  93 # endif
  94     .ptr_pthread_equal = __pthread_equal,
  95     .ptr___pthread_exit = __pthread_exit,
  96     .ptr_pthread_getschedparam = __pthread_getschedparam,
  97     .ptr_pthread_setschedparam = __pthread_setschedparam,
  98     .ptr_pthread_mutex_destroy = INTUSE(__pthread_mutex_destroy),
  99     .ptr_pthread_mutex_init = INTUSE(__pthread_mutex_init),
 100     .ptr_pthread_mutex_lock = INTUSE(__pthread_mutex_lock),
 101     .ptr_pthread_mutex_unlock = INTUSE(__pthread_mutex_unlock),
 102     .ptr_pthread_self = __pthread_self,
 103     .ptr_pthread_setcancelstate = __pthread_setcancelstate,
 104     .ptr_pthread_setcanceltype = __pthread_setcanceltype,
 105     .ptr___pthread_cleanup_upto = __pthread_cleanup_upto,
 106     .ptr___pthread_once = __pthread_once_internal,
 107     .ptr___pthread_rwlock_rdlock = __pthread_rwlock_rdlock_internal,
 108     .ptr___pthread_rwlock_wrlock = __pthread_rwlock_wrlock_internal,
 109     .ptr___pthread_rwlock_unlock = __pthread_rwlock_unlock_internal,
 110     .ptr___pthread_key_create = __pthread_key_create_internal,
 111     .ptr___pthread_getspecific = __pthread_getspecific_internal,
 112     .ptr___pthread_setspecific = __pthread_setspecific_internal,
 113     .ptr__pthread_cleanup_push_defer = __pthread_cleanup_push_defer,
 114     .ptr__pthread_cleanup_pop_restore = __pthread_cleanup_pop_restore,
 115     .ptr_nthreads = &__nptl_nthreads,
 116     .ptr___pthread_unwind = &__pthread_unwind,
 117     .ptr__nptl_deallocate_tsd = __nptl_deallocate_tsd,
 118     .ptr__nptl_setxid = __nptl_setxid,
 119     /* For now only the stack cache needs to be freed.  */
 120     .ptr_freeres = __free_stack_cache,
 121     .ptr_wait_lookup_done = __wait_lookup_done
 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);
 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);
 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 void
 239 __pthread_initialize_minimal_internal (void)
 240 {
 241 #ifndef SHARED
 242   /* Unlike in the dynamically linked case the dynamic linker has not
 243      taken care of initializing the TLS data structures.  */
 244   __libc_setup_tls (TLS_TCB_SIZE, TLS_TCB_ALIGN);
 245
 246   /* We must prevent gcc from being clever and move any of the
 247      following code ahead of the __libc_setup_tls call.  This function
 248      will initialize the thread register which is subsequently
 249      used.  */
 250   __asm __volatile ("");
 251 #endif
 252
 253   /* Minimal initialization of the thread descriptor.  */
 254   struct pthread *pd = THREAD_SELF;
 255   INTERNAL_SYSCALL_DECL (err);
 256   pd->pid = pd->tid = INTERNAL_SYSCALL (set_tid_address, err, 1, &pd->tid);
 257   THREAD_SETMEM (pd, specific[0], &pd->specific_1stblock[0]);
 258   THREAD_SETMEM (pd, user_stack, true);
 259   if (LLL_LOCK_INITIALIZER != 0)
 260     THREAD_SETMEM (pd, lock, LLL_LOCK_INITIALIZER);
 261 #if HP_TIMING_AVAIL
 262   THREAD_SETMEM (pd, cpuclock_offset, GL(dl_cpuclock_offset));
 263 #endif
 264
 265   /* Initialize the robust mutex data.  */
 266 #ifdef __PTHREAD_MUTEX_HAVE_PREV
 267   pd->robust_prev = &pd->robust_head;
 268 #endif
 269   pd->robust_head.list = &pd->robust_head;
 270 #ifdef __NR_set_robust_list
 271   pd->robust_head.futex_offset = (offsetof (pthread_mutex_t, __data.__lock)
 272                                   - offsetof (pthread_mutex_t,
 273                                               __data.__list.__next));
 274   int res = INTERNAL_SYSCALL (set_robust_list, err, 2, &pd->robust_head,
 275                               sizeof (struct robust_list_head));
 276   if (INTERNAL_SYSCALL_ERROR_P (res, err))
 277 #endif
 278     set_robust_list_not_avail ();
 279
 280   /* Set initial thread's stack block from 0 up to __libc_stack_end.
 281      It will be bigger than it actually is, but for unwind.c/pt-longjmp.c
 282      purposes this is good enough.  */
 283   THREAD_SETMEM (pd, stackblock_size, (size_t) __libc_stack_end);
 284
 285   /* Initialize the list of all running threads with the main thread.  */
 286   INIT_LIST_HEAD (&__stack_user);
 287   list_add (&pd->list, &__stack_user);
 288
 289
 290   /* Install the cancellation signal handler.  If for some reason we
 291      cannot install the handler we do not abort.  Maybe we should, but
 292      it is only asynchronous cancellation which is affected.  */
 293   struct sigaction sa;
 294   sa.sa_sigaction = sigcancel_handler;
 295   sa.sa_flags = SA_SIGINFO;
 296   __sigemptyset (&sa.sa_mask);
 297
 298   (void) __libc_sigaction (SIGCANCEL, &sa, NULL);
 299
 300   /* Install the handle to change the threads' uid/gid.  */
 301   sa.sa_sigaction = sighandler_setxid;
 302   sa.sa_flags = SA_SIGINFO | SA_RESTART;
 303
 304   (void) __libc_sigaction (SIGSETXID, &sa, NULL);
 305
 306   /* The parent process might have left the signals blocked.  Just in
 307      case, unblock it.  We reuse the signal mask in the sigaction
 308      structure.  It is already cleared.  */
 309   __sigaddset (&sa.sa_mask, SIGCANCEL);
 310   __sigaddset (&sa.sa_mask, SIGSETXID);
 311   (void) INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_UNBLOCK, &sa.sa_mask,
 312                            NULL, _NSIG / 8);
 313
 314   /* Get the size of the static and alignment requirements for the TLS
 315      block.  */
 316   size_t static_tls_align;
 317   _dl_get_tls_static_info (&__static_tls_size, &static_tls_align);
 318
 319   /* Make sure the size takes all the alignments into account.  */
 320   if (STACK_ALIGN > static_tls_align)
 321     static_tls_align = STACK_ALIGN;
 322   __static_tls_align_m1 = static_tls_align - 1;
 323
 324   __static_tls_size = roundup (__static_tls_size, static_tls_align);
 325
 326   /* Determine the default allowed stack size.  This is the size used
 327      in case the user does not specify one.  */
 328   struct rlimit limit;
 329   if (getrlimit (RLIMIT_STACK, &limit) != 0
 330       || limit.rlim_cur == RLIM_INFINITY)
 331     /* The system limit is not usable.  Use an architecture-specific
 332        default.  */
 333     limit.rlim_cur = ARCH_STACK_DEFAULT_SIZE;
 334   else if (limit.rlim_cur < PTHREAD_STACK_MIN)
 335     /* The system limit is unusably small.
 336        Use the minimal size acceptable.  */
 337     limit.rlim_cur = PTHREAD_STACK_MIN;
 338
 339   /* Make sure it meets the minimum size that allocate_stack
 340      (allocatestack.c) will demand, which depends on the page size.  */
 341   const uintptr_t pagesz = __sysconf (_SC_PAGESIZE);
 342   const size_t minstack = pagesz + __static_tls_size + MINIMAL_REST_STACK;
 343   if (limit.rlim_cur < minstack)
 344     limit.rlim_cur = minstack;
 345
 346   /* Round the resource limit up to page size.  */
 347   limit.rlim_cur = (limit.rlim_cur + pagesz - 1) & -pagesz;
 348   __default_stacksize = limit.rlim_cur;
 349
 350 #ifdef SHARED
 351   /* Transfer the old value from the dynamic linker's internal location.  */
 352   *__libc_dl_error_tsd () = *(*GL(dl_error_catch_tsd)) ();
 353   GL(dl_error_catch_tsd) = &__libc_dl_error_tsd;
 354
 355   /* Make __rtld_lock_{,un}lock_recursive use pthread_mutex_{,un}lock,
 356      keep the lock count from the ld.so implementation.  */
 357   GL(dl_rtld_lock_recursive) = (void *) INTUSE (__pthread_mutex_lock);
 358   GL(dl_rtld_unlock_recursive) = (void *) INTUSE (__pthread_mutex_unlock);
 359   unsigned int rtld_lock_count = GL(dl_load_lock).mutex.__data.__count;
 360   GL(dl_load_lock).mutex.__data.__count = 0;
 361   while (rtld_lock_count-- > 0)
 362     INTUSE (__pthread_mutex_lock) (&GL(dl_load_lock).mutex);
 363
 364   GL(dl_make_stack_executable_hook) = &__make_stacks_executable;
 365 #endif
 366
 367   GL(dl_init_static_tls) = &__pthread_init_static_tls;
 368
 369   /* Register the fork generation counter with the libc.  */
 370 #ifndef TLS_MULTIPLE_THREADS_IN_TCB
 371   __libc_multiple_threads_ptr =
 372 #endif
 373     __libc_pthread_init (&__fork_generation, __reclaim_stacks,
 374                          ptr_pthread_functions);
 375
 376   /* Determine whether the machine is SMP or not.  */
 377   __is_smp = is_smp_system ();
 378 }
 379 strong_alias (__pthread_initialize_minimal_internal,
 380               __pthread_initialize_minimal)