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 /* Version of the library, used in libthread_db to detect mismatches.  */
  64 static const char nptl_version[] __attribute_used__ = VERSION;
  65
  66
  67 #if defined USE_TLS && !defined SHARED
  68 extern void __libc_setup_tls (size_t tcbsize, size_t tcbalign);
  69 #endif
  70
  71
  72 #ifdef SHARED
  73 static const struct pthread_functions pthread_functions =
  74   {
  75     .ptr_pthread_attr_destroy = __pthread_attr_destroy,
  76 # if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1)
  77     .ptr___pthread_attr_init_2_0 = __pthread_attr_init_2_0,
  78 # endif
  79     .ptr___pthread_attr_init_2_1 = __pthread_attr_init_2_1,
  80     .ptr_pthread_attr_getdetachstate = __pthread_attr_getdetachstate,
  81     .ptr_pthread_attr_setdetachstate = __pthread_attr_setdetachstate,
  82     .ptr_pthread_attr_getinheritsched = __pthread_attr_getinheritsched,
  83     .ptr_pthread_attr_setinheritsched = __pthread_attr_setinheritsched,
  84     .ptr_pthread_attr_getschedparam = __pthread_attr_getschedparam,
  85     .ptr_pthread_attr_setschedparam = __pthread_attr_setschedparam,
  86     .ptr_pthread_attr_getschedpolicy = __pthread_attr_getschedpolicy,
  87     .ptr_pthread_attr_setschedpolicy = __pthread_attr_setschedpolicy,
  88     .ptr_pthread_attr_getscope = __pthread_attr_getscope,
  89     .ptr_pthread_attr_setscope = __pthread_attr_setscope,
  90     .ptr_pthread_condattr_destroy = __pthread_condattr_destroy,
  91     .ptr_pthread_condattr_init = __pthread_condattr_init,
  92     .ptr___pthread_cond_broadcast = __pthread_cond_broadcast,
  93     .ptr___pthread_cond_destroy = __pthread_cond_destroy,
  94     .ptr___pthread_cond_init = __pthread_cond_init,
  95     .ptr___pthread_cond_signal = __pthread_cond_signal,
  96     .ptr___pthread_cond_wait = __pthread_cond_wait,
  97     .ptr___pthread_cond_timedwait = __pthread_cond_timedwait,
  98 # if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_3_2)
  99     .ptr___pthread_cond_broadcast_2_0 = __pthread_cond_broadcast_2_0,
 100     .ptr___pthread_cond_destroy_2_0 = __pthread_cond_destroy_2_0,
 101     .ptr___pthread_cond_init_2_0 = __pthread_cond_init_2_0,
 102     .ptr___pthread_cond_signal_2_0 = __pthread_cond_signal_2_0,
 103     .ptr___pthread_cond_wait_2_0 = __pthread_cond_wait_2_0,
 104     .ptr___pthread_cond_timedwait_2_0 = __pthread_cond_timedwait_2_0,
 105 # endif
 106     .ptr_pthread_equal = __pthread_equal,
 107     .ptr___pthread_exit = __pthread_exit,
 108     .ptr_pthread_getschedparam = __pthread_getschedparam,
 109     .ptr_pthread_setschedparam = __pthread_setschedparam,
 110     .ptr_pthread_mutex_destroy = INTUSE(__pthread_mutex_destroy),
 111     .ptr_pthread_mutex_init = INTUSE(__pthread_mutex_init),
 112     .ptr_pthread_mutex_lock = INTUSE(__pthread_mutex_lock),
 113     .ptr_pthread_mutex_unlock = INTUSE(__pthread_mutex_unlock),
 114     .ptr_pthread_self = __pthread_self,
 115     .ptr_pthread_setcancelstate = __pthread_setcancelstate,
 116     .ptr_pthread_setcanceltype = __pthread_setcanceltype,
 117     .ptr___pthread_cleanup_upto = __pthread_cleanup_upto,
 118     .ptr___pthread_once = __pthread_once_internal,
 119     .ptr___pthread_rwlock_rdlock = __pthread_rwlock_rdlock_internal,
 120     .ptr___pthread_rwlock_wrlock = __pthread_rwlock_wrlock_internal,
 121     .ptr___pthread_rwlock_unlock = __pthread_rwlock_unlock_internal,
 122     .ptr___pthread_key_create = __pthread_key_create_internal,
 123     .ptr___pthread_getspecific = __pthread_getspecific_internal,
 124     .ptr___pthread_setspecific = __pthread_setspecific_internal,
 125     .ptr__pthread_cleanup_push_defer = __pthread_cleanup_push_defer,
 126     .ptr__pthread_cleanup_pop_restore = __pthread_cleanup_pop_restore,
 127     .ptr_nthreads = &__nptl_nthreads,
 128     .ptr___pthread_unwind = &__pthread_unwind,
 129     .ptr__nptl_deallocate_tsd = __nptl_deallocate_tsd,
 130     .ptr__nptl_setxid = __nptl_setxid
 131   };
 132 # define ptr_pthread_functions &pthread_functions
 133 #else
 134 # define ptr_pthread_functions NULL
 135 #endif
 136
 137
 138 /* For asynchronous cancellation we use a signal.  This is the handler.  */
 139 static void
 140 sigcancel_handler (int sig, siginfo_t *si, void *ctx)
 141 {
 142   /* Safety check.  It would be possible to call this function for
 143      other signals and send a signal from another process.  This is not
 144      correct and might even be a security problem.  Try to catch as
 145      many incorrect invocations as possible.  */
 146   if (sig != SIGCANCEL
 147 #ifdef __ASSUME_CORRECT_SI_PID
 148       /* Kernels before 2.5.75 stored the thread ID and not the process
 149          ID in si_pid so we skip this test.  */
 150       || si->si_pid != THREAD_GETMEM (THREAD_SELF, pid)
 151 #endif
 152       || si->si_code != SI_TKILL)
 153     return;
 154
 155   struct pthread *self = THREAD_SELF;
 156
 157   int oldval = THREAD_GETMEM (self, cancelhandling);
 158   while (1)
 159     {
 160       /* We are canceled now.  When canceled by another thread this flag
 161          is already set but if the signal is directly send (internally or
 162          from another process) is has to be done here.  */
 163       int newval = oldval | CANCELING_BITMASK | CANCELED_BITMASK;
 164
 165       if (oldval == newval || (oldval & EXITING_BITMASK) != 0)
 166         /* Already canceled or exiting.  */
 167         break;
 168
 169       int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
 170                                               oldval);
 171       if (curval == oldval)
 172         {
 173           /* Set the return value.  */
 174           THREAD_SETMEM (self, result, PTHREAD_CANCELED);
 175
 176           /* Make sure asynchronous cancellation is still enabled.  */
 177           if ((newval & CANCELTYPE_BITMASK) != 0)
 178             /* Run the registered destructors and terminate the thread.  */
 179             __do_cancel ();
 180
 181           break;
 182         }
 183
 184       oldval = curval;
 185     }
 186 }
 187
 188
 189 struct xid_command *__xidcmd attribute_hidden;
 190
 191 /* For asynchronous cancellation we use a signal.  This is the handler.  */
 192 static void
 193 sighandler_setxid (int sig, siginfo_t *si, void *ctx)
 194 {
 195   /* Safety check.  It would be possible to call this function for
 196      other signals and send a signal from another process.  This is not
 197      correct and might even be a security problem.  Try to catch as
 198      many incorrect invocations as possible.  */
 199   if (sig != SIGSETXID
 200 #ifdef __ASSUME_CORRECT_SI_PID
 201       /* Kernels before 2.5.75 stored the thread ID and not the process
 202          ID in si_pid so we skip this test.  */
 203       || si->si_pid != THREAD_GETMEM (THREAD_SELF, pid)
 204 #endif
 205       || si->si_code != SI_TKILL)
 206     return;
 207
 208   INTERNAL_SYSCALL_DECL (err);
 209   INTERNAL_SYSCALL_NCS (__xidcmd->syscall_no, err, 3, __xidcmd->id[0],
 210                         __xidcmd->id[1], __xidcmd->id[2]);
 211
 212   if (atomic_decrement_val (&__xidcmd->cntr) == 0)
 213     lll_futex_wake (&__xidcmd->cntr, 1);
 214
 215   /* Reset the SETXID flag.  */
 216   struct pthread *self = THREAD_SELF;
 217   int flags = THREAD_GETMEM (self, cancelhandling);
 218   THREAD_SETMEM (self, cancelhandling, flags & ~SETXID_BITMASK);
 219
 220   /* And release the futex.  */
 221   self->setxid_futex = 1;
 222   lll_futex_wake (&self->setxid_futex, 1);
 223 }
 224
 225
 226 /* When using __thread for this, we do it in libc so as not
 227    to give libpthread its own TLS segment just for this.  */
 228 extern void **__libc_dl_error_tsd (void) __attribute__ ((const));
 229
 230
 231 void
 232 __pthread_initialize_minimal_internal (void)
 233 {
 234 #ifndef SHARED
 235   /* Unlike in the dynamically linked case the dynamic linker has not
 236      taken care of initializing the TLS data structures.  */
 237   __libc_setup_tls (TLS_TCB_SIZE, TLS_TCB_ALIGN);
 238
 239   /* We must prevent gcc from being clever and move any of the
 240      following code ahead of the __libc_setup_tls call.  This function
 241      will initialize the thread register which is subsequently
 242      used.  */
 243   __asm __volatile ("");
 244 #endif
 245
 246   /* Minimal initialization of the thread descriptor.  */
 247   struct pthread *pd = THREAD_SELF;
 248   INTERNAL_SYSCALL_DECL (err);
 249   pd->pid = pd->tid = INTERNAL_SYSCALL (set_tid_address, err, 1, &pd->tid);
 250 #ifdef __PTHREAD_MUTEX_HAVE_PREV
 251   pd->robust_list.__prev = &pd->robust_list;
 252 #endif
 253   pd->robust_list.__next = &pd->robust_list;
 254   THREAD_SETMEM (pd, specific[0], &pd->specific_1stblock[0]);
 255   THREAD_SETMEM (pd, user_stack, true);
 256   if (LLL_LOCK_INITIALIZER != 0)
 257     THREAD_SETMEM (pd, lock, LLL_LOCK_INITIALIZER);
 258 #if HP_TIMING_AVAIL
 259   THREAD_SETMEM (pd, cpuclock_offset, GL(dl_cpuclock_offset));
 260 #endif
 261
 262   /* Set initial thread's stack block from 0 up to __libc_stack_end.
 263      It will be bigger than it actually is, but for unwind.c/pt-longjmp.c
 264      purposes this is good enough.  */
 265   THREAD_SETMEM (pd, stackblock_size, (size_t) __libc_stack_end);
 266
 267   /* Initialize the list of all running threads with the main thread.  */
 268   INIT_LIST_HEAD (&__stack_user);
 269   list_add (&pd->list, &__stack_user);
 270
 271
 272   /* Install the cancellation signal handler.  If for some reason we
 273      cannot install the handler we do not abort.  Maybe we should, but
 274      it is only asynchronous cancellation which is affected.  */
 275   struct sigaction sa;
 276   sa.sa_sigaction = sigcancel_handler;
 277   sa.sa_flags = SA_SIGINFO;
 278   __sigemptyset (&sa.sa_mask);
 279
 280   (void) __libc_sigaction (SIGCANCEL, &sa, NULL);
 281
 282   /* Install the handle to change the threads' uid/gid.  */
 283   sa.sa_sigaction = sighandler_setxid;
 284   sa.sa_flags = SA_SIGINFO | SA_RESTART;
 285
 286   (void) __libc_sigaction (SIGSETXID, &sa, NULL);
 287
 288   /* The parent process might have left the signals blocked.  Just in
 289      case, unblock it.  We reuse the signal mask in the sigaction
 290      structure.  It is already cleared.  */
 291   __sigaddset (&sa.sa_mask, SIGCANCEL);
 292   __sigaddset (&sa.sa_mask, SIGSETXID);
 293   (void) INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_UNBLOCK, &sa.sa_mask,
 294                            NULL, _NSIG / 8);
 295
 296   /* Get the size of the static and alignment requirements for the TLS
 297      block.  */
 298   size_t static_tls_align;
 299   _dl_get_tls_static_info (&__static_tls_size, &static_tls_align);
 300
 301   /* Make sure the size takes all the alignments into account.  */
 302   if (STACK_ALIGN > static_tls_align)
 303     static_tls_align = STACK_ALIGN;
 304   __static_tls_align_m1 = static_tls_align - 1;
 305
 306   __static_tls_size = roundup (__static_tls_size, static_tls_align);
 307
 308   /* Determine the default allowed stack size.  This is the size used
 309      in case the user does not specify one.  */
 310   struct rlimit limit;
 311   if (getrlimit (RLIMIT_STACK, &limit) != 0
 312       || limit.rlim_cur == RLIM_INFINITY)
 313     /* The system limit is not usable.  Use an architecture-specific
 314        default.  */
 315     limit.rlim_cur = ARCH_STACK_DEFAULT_SIZE;
 316   else if (limit.rlim_cur < PTHREAD_STACK_MIN)
 317     /* The system limit is unusably small.
 318        Use the minimal size acceptable.  */
 319     limit.rlim_cur = PTHREAD_STACK_MIN;
 320
 321   /* Make sure it meets the minimum size that allocate_stack
 322      (allocatestack.c) will demand, which depends on the page size.  */
 323   const uintptr_t pagesz = __sysconf (_SC_PAGESIZE);
 324   const size_t minstack = pagesz + __static_tls_size + MINIMAL_REST_STACK;
 325   if (limit.rlim_cur < minstack)
 326     limit.rlim_cur = minstack;
 327
 328   /* Round the resource limit up to page size.  */
 329   limit.rlim_cur = (limit.rlim_cur + pagesz - 1) & -pagesz;
 330   __default_stacksize = limit.rlim_cur;
 331
 332 #ifdef SHARED
 333   /* Transfer the old value from the dynamic linker's internal location.  */
 334   *__libc_dl_error_tsd () = *(*GL(dl_error_catch_tsd)) ();
 335   GL(dl_error_catch_tsd) = &__libc_dl_error_tsd;
 336
 337   /* Make __rtld_lock_{,un}lock_recursive use pthread_mutex_{,un}lock,
 338      keep the lock count from the ld.so implementation.  */
 339   GL(dl_rtld_lock_recursive) = (void *) INTUSE (__pthread_mutex_lock);
 340   GL(dl_rtld_unlock_recursive) = (void *) INTUSE (__pthread_mutex_unlock);
 341   unsigned int rtld_lock_count = GL(dl_load_lock).mutex.__data.__count;
 342   GL(dl_load_lock).mutex.__data.__count = 0;
 343   while (rtld_lock_count-- > 0)
 344     INTUSE (__pthread_mutex_lock) (&GL(dl_load_lock).mutex);
 345
 346   GL(dl_make_stack_executable_hook) = &__make_stacks_executable;
 347 #endif
 348
 349   GL(dl_init_static_tls) = &__pthread_init_static_tls;
 350
 351   /* Register the fork generation counter with the libc.  */
 352 #ifndef TLS_MULTIPLE_THREADS_IN_TCB
 353   __libc_multiple_threads_ptr =
 354 #endif
 355     __libc_pthread_init (&__fork_generation, __reclaim_stacks,
 356                          ptr_pthread_functions);
 357
 358   /* Determine whether the machine is SMP or not.  */
 359   __is_smp = is_smp_system ();
 360 }
 361 strong_alias (__pthread_initialize_minimal_internal,
 362               __pthread_initialize_minimal)