nptl/descr.h

   1 /* Copyright (C) 2002-2014 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 #ifndef _DESCR_H
  20 #define _DESCR_H        1
  21
  22 #include <limits.h>
  23 #include <sched.h>
  24 #include <setjmp.h>
  25 #include <stdbool.h>
  26 #include <sys/types.h>
  27 #include <hp-timing.h>
  28 #define __need_list_t
  29 #include <list.h>
  30 #include <lowlevellock.h>
  31 #include <pthreaddef.h>
  32 #include <dl-sysdep.h>
  33 #include "../nptl_db/thread_db.h"
  34 #include <tls.h>
  35 #ifdef HAVE_FORCED_UNWIND
  36 # include <unwind.h>
  37 #endif
  38 #define __need_res_state
  39 #include <resolv.h>
  40 #include <kernel-features.h>
  41
  42 #ifndef TCB_ALIGNMENT
  43 # define TCB_ALIGNMENT  sizeof (double)
  44 #endif
  45
  46
  47 /* We keep thread specific data in a special data structure, a two-level
  48    array.  The top-level array contains pointers to dynamically allocated
  49    arrays of a certain number of data pointers.  So we can implement a
  50    sparse array.  Each dynamic second-level array has
  51         PTHREAD_KEY_2NDLEVEL_SIZE
  52    entries.  This value shouldn't be too large.  */
  53 #define PTHREAD_KEY_2NDLEVEL_SIZE       32
  54
  55 /* We need to address PTHREAD_KEYS_MAX key with PTHREAD_KEY_2NDLEVEL_SIZE
  56    keys in each subarray.  */
  57 #define PTHREAD_KEY_1STLEVEL_SIZE \
  58   ((PTHREAD_KEYS_MAX + PTHREAD_KEY_2NDLEVEL_SIZE - 1) \
  59    / PTHREAD_KEY_2NDLEVEL_SIZE)
  60
  61
  62
  63
  64 /* Internal version of the buffer to store cancellation handler
  65    information.  */
  66 struct pthread_unwind_buf
  67 {
  68   struct
  69   {
  70     __jmp_buf jmp_buf;
  71     int mask_was_saved;
  72   } cancel_jmp_buf[1];
  73
  74   union
  75   {
  76     /* This is the placeholder of the public version.  */
  77     void *pad[4];
  78
  79     struct
  80     {
  81       /* Pointer to the previous cleanup buffer.  */
  82       struct pthread_unwind_buf *prev;
  83
  84       /* Backward compatibility: state of the old-style cleanup
  85          handler at the time of the previous new-style cleanup handler
  86          installment.  */
  87       struct _pthread_cleanup_buffer *cleanup;
  88
  89       /* Cancellation type before the push call.  */
  90       int canceltype;
  91     } data;
  92   } priv;
  93 };
  94
  95
  96 /* Opcodes and data types for communication with the signal handler to
  97    change user/group IDs.  */
  98 struct xid_command
  99 {
 100   int syscall_no;
 101   long int id[3];
 102   volatile int cntr;
 103 };
 104
 105
 106 /* Data structure used by the kernel to find robust futexes.  */
 107 struct robust_list_head
 108 {
 109   void *list;
 110   long int futex_offset;
 111   void *list_op_pending;
 112 };
 113
 114
 115 /* Data strcture used to handle thread priority protection.  */
 116 struct priority_protection_data
 117 {
 118   int priomax;
 119   unsigned int priomap[];
 120 };
 121
 122
 123 /* Thread descriptor data structure.  */
 124 struct pthread
 125 {
 126   union
 127   {
 128 #if !TLS_DTV_AT_TP
 129     /* This overlaps the TCB as used for TLS without threads (see tls.h).  */
 130     tcbhead_t header;
 131 #else
 132     struct
 133     {
 134       /* multiple_threads is enabled either when the process has spawned at
 135          least one thread or when a single-threaded process cancels itself.
 136          This enables additional code to introduce locking before doing some
 137          compare_and_exchange operations and also enable cancellation points.
 138          The concepts of multiple threads and cancellation points ideally
 139          should be separate, since it is not necessary for multiple threads to
 140          have been created for cancellation points to be enabled, as is the
 141          case is when single-threaded process cancels itself.
 142
 143          Since enabling multiple_threads enables additional code in
 144          cancellation points and compare_and_exchange operations, there is a
 145          potential for an unneeded performance hit when it is enabled in a
 146          single-threaded, self-canceling process.  This is OK though, since a
 147          single-threaded process will enable async cancellation only when it
 148          looks to cancel itself and is hence going to end anyway.  */
 149       int multiple_threads;
 150       int gscope_flag;
 151 # ifndef __ASSUME_PRIVATE_FUTEX
 152       int private_futex;
 153 # endif
 154     } header;
 155 #endif
 156
 157     /* This extra padding has no special purpose, and this structure layout
 158        is private and subject to change without affecting the official ABI.
 159        We just have it here in case it might be convenient for some
 160        implementation-specific instrumentation hack or suchlike.  */
 161     void *__padding[24];
 162   };
 163
 164   /* This descriptor's link on the `stack_used' or `__stack_user' list.  */
 165   list_t list;
 166
 167   /* Thread ID - which is also a 'is this thread descriptor (and
 168      therefore stack) used' flag.  */
 169   pid_t tid;
 170
 171   /* Process ID - thread group ID in kernel speak.  */
 172   pid_t pid;
 173
 174   /* List of robust mutexes the thread is holding.  */
 175 #ifdef __PTHREAD_MUTEX_HAVE_PREV
 176   void *robust_prev;
 177   struct robust_list_head robust_head;
 178
 179   /* The list above is strange.  It is basically a double linked list
 180      but the pointer to the next/previous element of the list points
 181      in the middle of the object, the __next element.  Whenever
 182      casting to __pthread_list_t we need to adjust the pointer
 183      first.  */
 184 # define QUEUE_PTR_ADJUST (offsetof (__pthread_list_t, __next))
 185
 186 # define ENQUEUE_MUTEX_BOTH(mutex, val)                                       \
 187   do {                                                                        \
 188     __pthread_list_t *next = (__pthread_list_t *)                             \
 189       ((((uintptr_t) THREAD_GETMEM (THREAD_SELF, robust_head.list)) & ~1ul)   \
 190        - QUEUE_PTR_ADJUST);                                                   \
 191     next->__prev = (void *) &mutex->__data.__list.__next;                     \
 192     mutex->__data.__list.__next = THREAD_GETMEM (THREAD_SELF,                 \
 193                                                  robust_head.list);           \
 194     mutex->__data.__list.__prev = (void *) &THREAD_SELF->robust_head;         \
 195     THREAD_SETMEM (THREAD_SELF, robust_head.list,                             \
 196                    (void *) (((uintptr_t) &mutex->__data.__list.__next)       \
 197                              | val));                                         \
 198   } while (0)
 199 # define DEQUEUE_MUTEX(mutex) \
 200   do {                                                                        \
 201     __pthread_list_t *next = (__pthread_list_t *)                             \
 202       ((char *) (((uintptr_t) mutex->__data.__list.__next) & ~1ul)            \
 203        - QUEUE_PTR_ADJUST);                                                   \
 204     next->__prev = mutex->__data.__list.__prev;                               \
 205     __pthread_list_t *prev = (__pthread_list_t *)                             \
 206       ((char *) (((uintptr_t) mutex->__data.__list.__prev) & ~1ul)            \
 207        - QUEUE_PTR_ADJUST);                                                   \
 208     prev->__next = mutex->__data.__list.__next;                               \
 209     mutex->__data.__list.__prev = NULL;                                       \
 210     mutex->__data.__list.__next = NULL;                                       \
 211   } while (0)
 212 #else
 213   union
 214   {
 215     __pthread_slist_t robust_list;
 216     struct robust_list_head robust_head;
 217   };
 218
 219 # define ENQUEUE_MUTEX_BOTH(mutex, val)                                       \
 220   do {                                                                        \
 221     mutex->__data.__list.__next                                               \
 222       = THREAD_GETMEM (THREAD_SELF, robust_list.__next);                      \
 223     THREAD_SETMEM (THREAD_SELF, robust_list.__next,                           \
 224                    (void *) (((uintptr_t) &mutex->__data.__list) | val));     \
 225   } while (0)
 226 # define DEQUEUE_MUTEX(mutex) \
 227   do {                                                                        \
 228     __pthread_slist_t *runp = (__pthread_slist_t *)                           \
 229       (((uintptr_t) THREAD_GETMEM (THREAD_SELF, robust_list.__next)) & ~1ul); \
 230     if (runp == &mutex->__data.__list)                                        \
 231       THREAD_SETMEM (THREAD_SELF, robust_list.__next, runp->__next);          \
 232     else                                                                      \
 233       {                                                                       \
 234         __pthread_slist_t *next = (__pthread_slist_t *)               \
 235           (((uintptr_t) runp->__next) & ~1ul);                                \
 236         while (next != &mutex->__data.__list)                                 \
 237           {                                                                   \
 238             runp = next;                                                      \
 239             next = (__pthread_slist_t *) (((uintptr_t) runp->__next) & ~1ul); \
 240           }                                                                   \
 241                                                                               \
 242         runp->__next = next->__next;                                          \
 243         mutex->__data.__list.__next = NULL;                                   \
 244       }                                                                       \
 245   } while (0)
 246 #endif
 247 #define ENQUEUE_MUTEX(mutex) ENQUEUE_MUTEX_BOTH (mutex, 0)
 248 #define ENQUEUE_MUTEX_PI(mutex) ENQUEUE_MUTEX_BOTH (mutex, 1)
 249
 250   /* List of cleanup buffers.  */
 251   struct _pthread_cleanup_buffer *cleanup;
 252
 253   /* Unwind information.  */
 254   struct pthread_unwind_buf *cleanup_jmp_buf;
 255 #define HAVE_CLEANUP_JMP_BUF
 256
 257   /* Flags determining processing of cancellation.  */
 258   int cancelhandling;
 259   /* Bit set if cancellation is disabled.  */
 260 #define CANCELSTATE_BIT         0
 261 #define CANCELSTATE_BITMASK     (0x01 << CANCELSTATE_BIT)
 262   /* Bit set if asynchronous cancellation mode is selected.  */
 263 #define CANCELTYPE_BIT          1
 264 #define CANCELTYPE_BITMASK      (0x01 << CANCELTYPE_BIT)
 265   /* Bit set if canceling has been initiated.  */
 266 #define CANCELING_BIT           2
 267 #define CANCELING_BITMASK       (0x01 << CANCELING_BIT)
 268   /* Bit set if canceled.  */
 269 #define CANCELED_BIT            3
 270 #define CANCELED_BITMASK        (0x01 << CANCELED_BIT)
 271   /* Bit set if thread is exiting.  */
 272 #define EXITING_BIT             4
 273 #define EXITING_BITMASK         (0x01 << EXITING_BIT)
 274   /* Bit set if thread terminated and TCB is freed.  */
 275 #define TERMINATED_BIT          5
 276 #define TERMINATED_BITMASK      (0x01 << TERMINATED_BIT)
 277   /* Bit set if thread is supposed to change XID.  */
 278 #define SETXID_BIT              6
 279 #define SETXID_BITMASK          (0x01 << SETXID_BIT)
 280   /* Mask for the rest.  Helps the compiler to optimize.  */
 281 #define CANCEL_RESTMASK         0xffffff80
 282
 283 #define CANCEL_ENABLED_AND_CANCELED(value) \
 284   (((value) & (CANCELSTATE_BITMASK | CANCELED_BITMASK | EXITING_BITMASK       \
 285                | CANCEL_RESTMASK | TERMINATED_BITMASK)) == CANCELED_BITMASK)
 286 #define CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS(value) \
 287   (((value) & (CANCELSTATE_BITMASK | CANCELTYPE_BITMASK | CANCELED_BITMASK    \
 288                | EXITING_BITMASK | CANCEL_RESTMASK | TERMINATED_BITMASK))     \
 289    == (CANCELTYPE_BITMASK | CANCELED_BITMASK))
 290
 291   /* Flags.  Including those copied from the thread attribute.  */
 292   int flags;
 293
 294   /* We allocate one block of references here.  This should be enough
 295      to avoid allocating any memory dynamically for most applications.  */
 296   struct pthread_key_data
 297   {
 298     /* Sequence number.  We use uintptr_t to not require padding on
 299        32- and 64-bit machines.  On 64-bit machines it helps to avoid
 300        wrapping, too.  */
 301     uintptr_t seq;
 302
 303     /* Data pointer.  */
 304     void *data;
 305   } specific_1stblock[PTHREAD_KEY_2NDLEVEL_SIZE];
 306
 307   /* Two-level array for the thread-specific data.  */
 308   struct pthread_key_data *specific[PTHREAD_KEY_1STLEVEL_SIZE];
 309
 310   /* Flag which is set when specific data is set.  */
 311   bool specific_used;
 312
 313   /* True if events must be reported.  */
 314   bool report_events;
 315
 316   /* True if the user provided the stack.  */
 317   bool user_stack;
 318
 319   /* True if thread must stop at startup time.  */
 320   bool stopped_start;
 321
 322   /* The parent's cancel handling at the time of the pthread_create
 323      call.  This might be needed to undo the effects of a cancellation.  */
 324   int parent_cancelhandling;
 325
 326   /* Lock to synchronize access to the descriptor.  */
 327   int lock;
 328
 329   /* Lock for synchronizing setxid calls.  */
 330   int setxid_futex;
 331
 332 #if HP_TIMING_AVAIL
 333   /* Offset of the CPU clock at start thread start time.  */
 334   hp_timing_t cpuclock_offset;
 335 #endif
 336
 337   /* If the thread waits to join another one the ID of the latter is
 338      stored here.
 339
 340      In case a thread is detached this field contains a pointer of the
 341      TCB if the thread itself.  This is something which cannot happen
 342      in normal operation.  */
 343   struct pthread *joinid;
 344   /* Check whether a thread is detached.  */
 345 #define IS_DETACHED(pd) ((pd)->joinid == (pd))
 346
 347   /* The result of the thread function.  */
 348   void *result;
 349
 350   /* Scheduling parameters for the new thread.  */
 351   struct sched_param schedparam;
 352   int schedpolicy;
 353
 354   /* Start position of the code to be executed and the argument passed
 355      to the function.  */
 356   void *(*start_routine) (void *);
 357   void *arg;
 358
 359   /* Debug state.  */
 360   td_eventbuf_t eventbuf;
 361   /* Next descriptor with a pending event.  */
 362   struct pthread *nextevent;
 363
 364 #ifdef HAVE_FORCED_UNWIND
 365   /* Machine-specific unwind info.  */
 366   struct _Unwind_Exception exc;
 367 #endif
 368
 369   /* If nonzero pointer to area allocated for the stack and its
 370      size.  */
 371   void *stackblock;
 372   size_t stackblock_size;
 373   /* Size of the included guard area.  */
 374   size_t guardsize;
 375   /* This is what the user specified and what we will report.  */
 376   size_t reported_guardsize;
 377
 378   /* Thread Priority Protection data.  */
 379   struct priority_protection_data *tpp;
 380
 381   /* Resolver state.  */
 382   struct __res_state res;
 383
 384   /* This member must be last.  */
 385   char end_padding[];
 386
 387 #define PTHREAD_STRUCT_END_PADDING \
 388   (sizeof (struct pthread) - offsetof (struct pthread, end_padding))
 389 } __attribute ((aligned (TCB_ALIGNMENT)));
 390
 391
 392 #endif  /* descr.h */