htl/pt-internal.h

   1 /* Internal definitions for pthreads library.
   2    Copyright (C) 2000-2023 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   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    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _PT_INTERNAL_H
  20 #define _PT_INTERNAL_H  1
  21
  22 #include <pthread.h>
  23 #include <stddef.h>
  24 #include <sched.h>
  25 #include <signal.h>
  26 #include <assert.h>
  27 #include <bits/types/res_state.h>
  28
  29 #include <atomic.h>
  30
  31 #include <pt-key.h>
  32
  33 #include <pt-sysdep.h>
  34 #include <pt-machdep.h>
  35
  36 #if IS_IN (libpthread)
  37 # include <ldsodefs.h>
  38 #endif
  39
  40 #include <tls.h>
  41
  42 /* Thread state.  */
  43 enum pthread_state
  44 {
  45   /* The thread is running and joinable.  */
  46   PTHREAD_JOINABLE = 0,
  47   /* The thread is running and detached.  */
  48   PTHREAD_DETACHED,
  49   /* A joinable thread exited and its return code is available.  */
  50   PTHREAD_EXITED,
  51 };
  52
  53 #ifndef PTHREAD_KEY_MEMBERS
  54 # define PTHREAD_KEY_MEMBERS
  55 #endif
  56
  57 #ifndef PTHREAD_SYSDEP_MEMBERS
  58 # define PTHREAD_SYSDEP_MEMBERS
  59 #endif
  60
  61 /* This structure describes a POSIX thread.  */
  62 struct __pthread
  63 {
  64   /* Thread ID.  */
  65   pthread_t thread;
  66
  67   unsigned int nr_refs;         /* Detached threads have a self reference only,
  68                                    while joinable threads have two references.
  69                                    These are used to keep the structure valid at
  70                                    thread destruction.  Detaching/joining a thread
  71                                    drops a reference.  */
  72
  73   /* Cancellation.  */
  74   pthread_mutex_t cancel_lock;  /* Protect cancel_xxx members.  */
  75   void (*cancel_hook) (void *); /* Called to unblock a thread blocking
  76                                    in a cancellation point (namely,
  77                                    __pthread_cond_timedwait_internal).  */
  78   void *cancel_hook_arg;
  79   int cancel_state;
  80   int cancel_type;
  81   int cancel_pending;
  82
  83   /* Thread stack.  */
  84   void *stackaddr;
  85   size_t stacksize;
  86   size_t guardsize;
  87   int stack;                    /* Nonzero if the stack was allocated.  */
  88
  89   /* Exit status.  */
  90   void *status;
  91
  92   /* Thread state.  */
  93   enum pthread_state state;
  94   pthread_mutex_t state_lock;   /* Locks the state.  */
  95   pthread_cond_t state_cond;    /* Signalled when the state changes.  */
  96   bool terminated;              /* Whether the kernel thread is over
  97                                    and we can reuse this structure.  */
  98
  99   /* Resolver state.  */
 100   struct __res_state res_state;
 101
 102   /* Indicates whether is a C11 thread created by thrd_creat.  */
 103   bool c11;
 104
 105   /* Initial sigset for the thread.  */
 106   sigset_t init_sigset;
 107
 108   /* Thread context.  */
 109   struct pthread_mcontext mcontext;
 110
 111   PTHREAD_KEY_MEMBERS
 112
 113   PTHREAD_SYSDEP_MEMBERS
 114
 115   tcbhead_t *tcb;
 116
 117   /* Queue links.  Since PREVP is used to determine if a thread has been
 118      awaken, it must be protected by the queue lock.  */
 119   struct __pthread *next, **prevp;
 120 };
 121
 122 /* Enqueue an element THREAD on the queue *HEAD.  */
 123 static inline void
 124 __pthread_enqueue (struct __pthread **head, struct __pthread *thread)
 125 {
 126   assert (thread->prevp == 0);
 127
 128   thread->next = *head;
 129   thread->prevp = head;
 130   if (*head)
 131     (*head)->prevp = &thread->next;
 132   *head = thread;
 133 }
 134
 135 /* Dequeue the element THREAD from the queue it is connected to.  */
 136 static inline void
 137 __pthread_dequeue (struct __pthread *thread)
 138 {
 139   assert (thread);
 140   assert (thread->prevp);
 141
 142   if (thread->next)
 143     thread->next->prevp = thread->prevp;
 144   *thread->prevp = thread->next;
 145   thread->prevp = 0;
 146 }
 147
 148 /* Iterate over QUEUE storing each element in ELEMENT.  */
 149 #define __pthread_queue_iterate(queue, element)                         \
 150   for (struct __pthread *__pdi_next = (queue);                          \
 151        ((element) = __pdi_next)                                         \
 152          && ((__pdi_next = __pdi_next->next),                           \
 153              1);                                                        \
 154        )
 155
 156 /* Iterate over QUEUE dequeuing each element, storing it in
 157    ELEMENT.  */
 158 #define __pthread_dequeuing_iterate(queue, element)                     \
 159   for (struct __pthread *__pdi_next = (queue);                          \
 160        ((element) = __pdi_next)                                         \
 161          && ((__pdi_next = __pdi_next->next),                           \
 162              ((element)->prevp = 0),                                    \
 163              1);                                                        \
 164        )
 165
 166 /* The total number of threads currently active.  */
 167 extern unsigned int __pthread_total;
 168
 169 /* Concurrency hint.  */
 170 extern int __pthread_concurrency;
 171
 172 /* The size of the thread ID lookup table.  */
 173 extern int __pthread_max_threads;
 174
 175 #define __pthread_getid(thread) \
 176   ({ struct __pthread *__t = NULL;                                           \
 177      __libc_rwlock_rdlock (GL (dl_pthread_threads_lock));                    \
 178      if (thread <= __pthread_max_threads)                                    \
 179        __t = GL (dl_pthread_threads)[thread - 1];                            \
 180      __libc_rwlock_unlock (GL (dl_pthread_threads_lock));                    \
 181      __t; })
 182
 183 #define __pthread_setid(thread, pthread) \
 184   __libc_rwlock_wrlock (GL (dl_pthread_threads_lock));                       \
 185   GL (dl_pthread_threads)[thread - 1] = pthread;                             \
 186   __libc_rwlock_unlock (GL (dl_pthread_threads_lock));
 187
 188 /* Similar to pthread_self, but returns the thread descriptor instead
 189    of the thread ID.  */
 190 #ifndef _pthread_self
 191 extern struct __pthread *_pthread_self (void);
 192 #endif
 193
 194 /* Stores the stack of cleanup handlers for the thread.  */
 195 extern __thread struct __pthread_cancelation_handler *__pthread_cleanup_stack;
 196 \f
 197
 198 /* Initialize the pthreads library.  */
 199 extern void ___pthread_init (void);
 200
 201 /* Internal version of pthread_create.  Rather than return the new
 202    tid, we return the whole __pthread structure in *PTHREAD.  */
 203 extern int __pthread_create_internal (struct __pthread **__restrict pthread,
 204                                       const pthread_attr_t *__restrict attr,
 205                                       void *(*start_routine) (void *),
 206                                       void *__restrict arg);
 207
 208 /* Allocate a new thread structure and a pthread thread ID (but not a
 209    kernel thread or a stack).  THREAD has one reference.  */
 210 extern int __pthread_alloc (struct __pthread **thread);
 211
 212 /* Deallocate the content of the thread structure.  This is the dual of
 213    __pthread_alloc (N.B. it does not call __pthread_stack_dealloc nor
 214    __pthread_thread_terminate).  THREAD loses one reference, and if
 215    if the reference counter drops to 0 this returns 1, and the caller has
 216    to call __pthread_dealloc_finish when it is really finished with using
 217    THREAD.  */
 218 extern void __pthread_dealloc (struct __pthread *thread);
 219
 220 /* Confirm deallocating the thread structure.  Before calling this
 221    the structure will not be reused yet.  */
 222 extern void __pthread_dealloc_finish (struct __pthread *pthread);
 223
 224
 225 /* Allocate a stack of size STACKSIZE.  The stack base shall be
 226    returned in *STACKADDR.  */
 227 extern int __pthread_stack_alloc (void **stackaddr, size_t stacksize);
 228
 229 /* Deallocate the stack STACKADDR of size STACKSIZE.  */
 230 extern void __pthread_stack_dealloc (void *stackaddr, size_t stacksize);
 231
 232
 233 /* Setup thread THREAD's context.  */
 234 extern int __pthread_setup (struct __pthread *__restrict thread,
 235                             void (*entry_point) (struct __pthread *,
 236                                                  void *(*)(void *),
 237                                                  void *),
 238                             void *(*start_routine) (void *),
 239                             void *__restrict arg);
 240
 241
 242 /* Allocate a kernel thread (and any miscellaneous system dependent
 243    resources) for THREAD; it must not be placed on the run queue.  */
 244 extern int __pthread_thread_alloc (struct __pthread *thread);
 245
 246 /* Start THREAD making it eligible to run.  */
 247 extern int __pthread_thread_start (struct __pthread *thread);
 248
 249 /* Terminate the kernel thread associated with THREAD, and deallocate its
 250    stack as well as any other kernel resource associated with it.
 251    In addition, THREAD looses one reference.
 252
 253    This function can be called by any thread, including the target thread.
 254    Since some resources that are destroyed along the kernel thread are
 255    stored in thread-local variables, the conditions required for this
 256    function to behave correctly are a bit unusual : as long as the target
 257    thread hasn't been started, any thread can terminate it, but once it
 258    has started, no other thread can terminate it, so that thread-local
 259    variables created by that thread are correctly released.  */
 260 extern void __pthread_thread_terminate (struct __pthread *thread);
 261
 262
 263 /* Called by a thread just before it calls the provided start
 264    routine.  */
 265 extern void __pthread_startup (void);
 266
 267 /* Block THREAD.  */
 268 extern void __pthread_block (struct __pthread *thread);
 269
 270 /* Block THREAD until *ABSTIME is reached.  */
 271 extern error_t __pthread_timedblock (struct __pthread *__restrict thread,
 272                                      const struct timespec *__restrict abstime,
 273                                      clockid_t clock_id);
 274
 275 /* Block THREAD with interrupts.  */
 276 extern error_t __pthread_block_intr (struct __pthread *thread);
 277
 278 /* Block THREAD until *ABSTIME is reached, with interrupts.  */
 279 extern error_t __pthread_timedblock_intr (struct __pthread *__restrict thread,
 280                                           const struct timespec *__restrict abstime,
 281                                           clockid_t clock_id);
 282
 283 /* Wakeup THREAD.  */
 284 extern void __pthread_wakeup (struct __pthread *thread);
 285
 286
 287 /* Perform a cancelation.  The CANCEL_LOCK member of the given thread must
 288    be locked before calling this function, which must unlock it.  */
 289 extern int __pthread_do_cancel (struct __pthread *thread);
 290
 291
 292 /* Initialize the thread specific data structures.  THREAD must be the
 293    calling thread.  */
 294 extern error_t __pthread_init_specific (struct __pthread *thread);
 295
 296 /* Call the destructors on all of the thread specific data in THREAD.
 297    THREAD must be the calling thread.  */
 298 extern void __pthread_destroy_specific (struct __pthread *thread);
 299
 300
 301 /* Initialize newly create thread *THREAD's signal state data
 302    structures.  */
 303 extern error_t __pthread_sigstate_init (struct __pthread *thread);
 304
 305 /* Destroy the signal state data structures associcated with thread
 306    *THREAD.  */
 307 extern void __pthread_sigstate_destroy (struct __pthread *thread);
 308
 309 /* Modify thread *THREAD's signal state.  */
 310 extern error_t __pthread_sigstate (struct __pthread *__restrict thread, int how,
 311                                    const sigset_t *__restrict set,
 312                                    sigset_t *__restrict oset,
 313                                    int clear_pending);
 314
 315 /* If supported, check that MUTEX is locked by the caller.  */
 316 extern int __pthread_mutex_checklocked (pthread_mutex_t *mtx);
 317 \f
 318
 319 /* Default thread attributes.  */
 320 extern struct __pthread_attr __pthread_default_attr;
 321
 322 /* Default barrier attributes.  */
 323 extern const struct __pthread_barrierattr __pthread_default_barrierattr;
 324
 325 /* Default rdlock attributes.  */
 326 extern const struct __pthread_rwlockattr __pthread_default_rwlockattr;
 327
 328 /* Default condition attributes.  */
 329 extern const struct __pthread_condattr __pthread_default_condattr;
 330
 331 /* Semaphore encoding.
 332    See nptl implementation for the details.  */
 333 struct new_sem
 334 {
 335 #if __HAVE_64B_ATOMICS
 336   /* The data field holds both value (in the least-significant 32 bits) and
 337      nwaiters.  */
 338 # if __BYTE_ORDER == __LITTLE_ENDIAN
 339 #  define SEM_VALUE_OFFSET 0
 340 # elif __BYTE_ORDER == __BIG_ENDIAN
 341 #  define SEM_VALUE_OFFSET 1
 342 # else
 343 #  error Unsupported byte order.
 344 # endif
 345 # define SEM_NWAITERS_SHIFT 32
 346 # define SEM_VALUE_MASK (~(unsigned int)0)
 347   uint64_t data;
 348   int pshared;
 349 #define __SEMAPHORE_INITIALIZER(value, pshared) \
 350   { (value), (pshared) }
 351 #else
 352 # define SEM_VALUE_SHIFT 1
 353 # define SEM_NWAITERS_MASK ((unsigned int)1)
 354   unsigned int value;
 355   unsigned int nwaiters;
 356   int pshared;
 357 #define __SEMAPHORE_INITIALIZER(value, pshared) \
 358   { (value) << SEM_VALUE_SHIFT, 0, (pshared) }
 359 #endif
 360 };
 361
 362 extern int __sem_waitfast (struct new_sem *isem, int definitive_result);
 363
 364 #endif /* pt-internal.h */