nptl/descr.h

   1 /* Copyright (C) 2002-2015 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   volatile int error; /* -1: no call yet, 0: success seen, >0: error seen.  */
 104 };
 105
 106
 107 /* Data structure used by the kernel to find robust futexes.  */
 108 struct robust_list_head
 109 {
 110   void *list;
 111   long int futex_offset;
 112   void *list_op_pending;
 113 };
 114
 115
 116 /* Data strcture used to handle thread priority protection.  */
 117 struct priority_protection_data
 118 {
 119   int priomax;
 120   unsigned int priomap[];
 121 };
 122
 123
 124 /* Thread descriptor data structure.  */
 125 struct pthread
 126 {
 127   union
 128   {
 129 #if !TLS_DTV_AT_TP
 130     /* This overlaps the TCB as used for TLS without threads (see tls.h).  */
 131     tcbhead_t header;
 132 #else
 133     struct
 134     {
 135       /* multiple_threads is enabled either when the process has spawned at
 136          least one thread or when a single-threaded process cancels itself.
 137          This enables additional code to introduce locking before doing some
 138          compare_and_exchange operations and also enable cancellation points.
 139          The concepts of multiple threads and cancellation points ideally
 140          should be separate, since it is not necessary for multiple threads to
 141          have been created for cancellation points to be enabled, as is the
 142          case is when single-threaded process cancels itself.
 143
 144          Since enabling multiple_threads enables additional code in
 145          cancellation points and compare_and_exchange operations, there is a
 146          potential for an unneeded performance hit when it is enabled in a
 147          single-threaded, self-canceling process.  This is OK though, since a
 148          single-threaded process will enable async cancellation only when it
 149          looks to cancel itself and is hence going to end anyway.  */
 150       int multiple_threads;
 151       int gscope_flag;
 152 # ifndef __ASSUME_PRIVATE_FUTEX
 153       int private_futex;
 154 # endif
 155     } header;
 156 #endif
 157
 158     /* This extra padding has no special purpose, and this structure layout
 159        is private and subject to change without affecting the official ABI.
 160        We just have it here in case it might be convenient for some
 161        implementation-specific instrumentation hack or suchlike.  */
 162     void *__padding[24];
 163   };
 164
 165   /* This descriptor's link on the `stack_used' or `__stack_user' list.  */
 166   list_t list;
 167
 168   /* Thread ID - which is also a 'is this thread descriptor (and
 169      therefore stack) used' flag.  */
 170   pid_t tid;
 171
 172   /* Process ID - thread group ID in kernel speak.  */
 173   pid_t pid;
 174
 175   /* List of robust mutexes the thread is holding.  */
 176 #ifdef __PTHREAD_MUTEX_HAVE_PREV
 177   void *robust_prev;
 178   struct robust_list_head robust_head;
 179
 180   /* The list above is strange.  It is basically a double linked list
 181      but the pointer to the next/previous element of the list points
 182      in the middle of the object, the __next element.  Whenever
 183      casting to __pthread_list_t we need to adjust the pointer
 184      first.  */
 185 # define QUEUE_PTR_ADJUST (offsetof (__pthread_list_t, __next))
 186
 187 # define ENQUEUE_MUTEX_BOTH(mutex, val)                                       \
 188   do {                                                                        \
 189     __pthread_list_t *next = (__pthread_list_t *)                             \
 190       ((((uintptr_t) THREAD_GETMEM (THREAD_SELF, robust_head.list)) & ~1ul)   \
 191        - QUEUE_PTR_ADJUST);                                                   \
 192     next->__prev = (void *) &mutex->__data.__list.__next;                     \
 193     mutex->__data.__list.__next = THREAD_GETMEM (THREAD_SELF,                 \
 194                                                  robust_head.list);           \
 195     mutex->__data.__list.__prev = (void *) &THREAD_SELF->robust_head;         \
 196     THREAD_SETMEM (THREAD_SELF, robust_head.list,                             \
 197                    (void *) (((uintptr_t) &mutex->__data.__list.__next)       \
 198                              | val));                                         \
 199   } while (0)
 200 # define DEQUEUE_MUTEX(mutex) \
 201   do {                                                                        \
 202     __pthread_list_t *next = (__pthread_list_t *)                             \
 203       ((char *) (((uintptr_t) mutex->__data.__list.__next) & ~1ul)            \
 204        - QUEUE_PTR_ADJUST);                                                   \
 205     next->__prev = mutex->__data.__list.__prev;                               \
 206     __pthread_list_t *prev = (__pthread_list_t *)                             \
 207       ((char *) (((uintptr_t) mutex->__data.__list.__prev) & ~1ul)            \
 208        - QUEUE_PTR_ADJUST);                                                   \
 209     prev->__next = mutex->__data.__list.__next;                               \
 210     mutex->__data.__list.__prev = NULL;                                       \
 211     mutex->__data.__list.__next = NULL;                                       \
 212   } while (0)
 213 #else
 214   union
 215   {
 216     __pthread_slist_t robust_list;
 217     struct robust_list_head robust_head;
 218   };
 219
 220 # define ENQUEUE_MUTEX_BOTH(mutex, val)                                       \
 221   do {                                                                        \
 222     mutex->__data.__list.__next                                               \
 223       = THREAD_GETMEM (THREAD_SELF, robust_list.__next);                      \
 224     THREAD_SETMEM (THREAD_SELF, robust_list.__next,                           \
 225                    (void *) (((uintptr_t) &mutex->__data.__list) | val));     \
 226   } while (0)
 227 # define DEQUEUE_MUTEX(mutex) \
 228   do {                                                                        \
 229     __pthread_slist_t *runp = (__pthread_slist_t *)                           \
 230       (((uintptr_t) THREAD_GETMEM (THREAD_SELF, robust_list.__next)) & ~1ul); \
 231     if (runp == &mutex->__data.__list)                                        \
 232       THREAD_SETMEM (THREAD_SELF, robust_list.__next, runp->__next);          \
 233     else                                                                      \
 234       {                                                                       \
 235         __pthread_slist_t *next = (__pthread_slist_t *)               \
 236           (((uintptr_t) runp->__next) & ~1ul);                                \
 237         while (next != &mutex->__data.__list)                                 \
 238           {                                                                   \
 239             runp = next;                                                      \
 240             next = (__pthread_slist_t *) (((uintptr_t) runp->__next) & ~1ul); \
 241           }                                                                   \
 242                                                                               \
 243         runp->__next = next->__next;                                          \
 244         mutex->__data.__list.__next = NULL;                                   \
 245       }                                                                       \
 246   } while (0)
 247 #endif
 248 #define ENQUEUE_MUTEX(mutex) ENQUEUE_MUTEX_BOTH (mutex, 0)
 249 #define ENQUEUE_MUTEX_PI(mutex) ENQUEUE_MUTEX_BOTH (mutex, 1)
 250
 251   /* List of cleanup buffers.  */
 252   struct _pthread_cleanup_buffer *cleanup;
 253
 254   /* Unwind information.  */
 255   struct pthread_unwind_buf *cleanup_jmp_buf;
 256 #define HAVE_CLEANUP_JMP_BUF
 257
 258   /* Flags determining processing of cancellation.  */
 259   int cancelhandling;
 260   /* Bit set if cancellation is disabled.  */
 261 #define CANCELSTATE_BIT         0
 262 #define CANCELSTATE_BITMASK     (0x01 << CANCELSTATE_BIT)
 263   /* Bit set if asynchronous cancellation mode is selected.  */
 264 #define CANCELTYPE_BIT          1
 265 #define CANCELTYPE_BITMASK      (0x01 << CANCELTYPE_BIT)
 266   /* Bit set if canceling has been initiated.  */
 267 #define CANCELING_BIT           2
 268 #define CANCELING_BITMASK       (0x01 << CANCELING_BIT)
 269   /* Bit set if canceled.  */
 270 #define CANCELED_BIT            3
 271 #define CANCELED_BITMASK        (0x01 << CANCELED_BIT)
 272   /* Bit set if thread is exiting.  */
 273 #define EXITING_BIT             4
 274 #define EXITING_BITMASK         (0x01 << EXITING_BIT)
 275   /* Bit set if thread terminated and TCB is freed.  */
 276 #define TERMINATED_BIT          5
 277 #define TERMINATED_BITMASK      (0x01 << TERMINATED_BIT)
 278   /* Bit set if thread is supposed to change XID.  */
 279 #define SETXID_BIT              6
 280 #define SETXID_BITMASK          (0x01 << SETXID_BIT)
 281   /* Mask for the rest.  Helps the compiler to optimize.  */
 282 #define CANCEL_RESTMASK         0xffffff80
 283
 284 #define CANCEL_ENABLED_AND_CANCELED(value) \
 285   (((value) & (CANCELSTATE_BITMASK | CANCELED_BITMASK | EXITING_BITMASK       \
 286                | CANCEL_RESTMASK | TERMINATED_BITMASK)) == CANCELED_BITMASK)
 287 #define CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS(value) \
 288   (((value) & (CANCELSTATE_BITMASK | CANCELTYPE_BITMASK | CANCELED_BITMASK    \
 289                | EXITING_BITMASK | CANCEL_RESTMASK | TERMINATED_BITMASK))     \
 290    == (CANCELTYPE_BITMASK | CANCELED_BITMASK))
 291
 292   /* Flags.  Including those copied from the thread attribute.  */
 293   int flags;
 294
 295   /* We allocate one block of references here.  This should be enough
 296      to avoid allocating any memory dynamically for most applications.  */
 297   struct pthread_key_data
 298   {
 299     /* Sequence number.  We use uintptr_t to not require padding on
 300        32- and 64-bit machines.  On 64-bit machines it helps to avoid
 301        wrapping, too.  */
 302     uintptr_t seq;
 303
 304     /* Data pointer.  */
 305     void *data;
 306   } specific_1stblock[PTHREAD_KEY_2NDLEVEL_SIZE];
 307
 308   /* Two-level array for the thread-specific data.  */
 309   struct pthread_key_data *specific[PTHREAD_KEY_1STLEVEL_SIZE];
 310
 311   /* Flag which is set when specific data is set.  */
 312   bool specific_used;
 313
 314   /* True if events must be reported.  */
 315   bool report_events;
 316
 317   /* True if the user provided the stack.  */
 318   bool user_stack;
 319
 320   /* True if thread must stop at startup time.  */
 321   bool stopped_start;
 322
 323   /* The parent's cancel handling at the time of the pthread_create
 324      call.  This might be needed to undo the effects of a cancellation.  */
 325   int parent_cancelhandling;
 326
 327   /* Lock to synchronize access to the descriptor.  */
 328   int lock;
 329
 330   /* Lock for synchronizing setxid calls.  */
 331   int setxid_futex;
 332
 333 #if HP_TIMING_AVAIL
 334   /* Offset of the CPU clock at start thread start time.  */
 335   hp_timing_t cpuclock_offset;
 336 #endif
 337
 338   /* If the thread waits to join another one the ID of the latter is
 339      stored here.
 340
 341      In case a thread is detached this field contains a pointer of the
 342      TCB if the thread itself.  This is something which cannot happen
 343      in normal operation.  */
 344   struct pthread *joinid;
 345   /* Check whether a thread is detached.  */
 346 #define IS_DETACHED(pd) ((pd)->joinid == (pd))
 347
 348   /* The result of the thread function.  */
 349   void *result;
 350
 351   /* Scheduling parameters for the new thread.  */
 352   struct sched_param schedparam;
 353   int schedpolicy;
 354
 355   /* Start position of the code to be executed and the argument passed
 356      to the function.  */
 357   void *(*start_routine) (void *);
 358   void *arg;
 359
 360   /* Debug state.  */
 361   td_eventbuf_t eventbuf;
 362   /* Next descriptor with a pending event.  */
 363   struct pthread *nextevent;
 364
 365 #ifdef HAVE_FORCED_UNWIND
 366   /* Machine-specific unwind info.  */
 367   struct _Unwind_Exception exc;
 368 #endif
 369
 370   /* If nonzero pointer to area allocated for the stack and its
 371      size.  */
 372   void *stackblock;
 373   size_t stackblock_size;
 374   /* Size of the included guard area.  */
 375   size_t guardsize;
 376   /* This is what the user specified and what we will report.  */
 377   size_t reported_guardsize;
 378
 379   /* Thread Priority Protection data.  */
 380   struct priority_protection_data *tpp;
 381
 382   /* Resolver state.  */
 383   struct __res_state res;
 384
 385   /* This member must be last.  */
 386   char end_padding[];
 387
 388 #define PTHREAD_STRUCT_END_PADDING \
 389   (sizeof (struct pthread) - offsetof (struct pthread, end_padding))
 390 } __attribute ((aligned (TCB_ALIGNMENT)));
 391
 392
 393 #endif  /* descr.h */