libpthread/nptl/descr.h

   1 /* Copyright (C) 2002-2006, 2007, 2008, 2009 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 #include <list.h>
  29 #include <lowlevellock.h>
  30 #include <pthreaddef.h>
  31 #include "../nptl_db/thread_db.h"
  32 #include <tls.h>
  33 #ifdef HAVE_FORCED_UNWIND
  34 # include <unwind.h>
  35 #endif
  36 #define __need_res_state
  37 #include <resolv.h>
  38 #include <bits/kernel-features.h>
  39 #include "uClibc-glue.h"
  40
  41 #ifndef TCB_ALIGNMENT
  42 # define TCB_ALIGNMENT  sizeof (double)
  43 #endif
  44
  45
  46 /* We keep thread specific data in a special data structure, a two-level
  47    array.  The top-level array contains pointers to dynamically allocated
  48    arrays of a certain number of data pointers.  So we can implement a
  49    sparse array.  Each dynamic second-level array has
  50         PTHREAD_KEY_2NDLEVEL_SIZE
  51    entries.  This value shouldn't be too large.  */
  52 #define PTHREAD_KEY_2NDLEVEL_SIZE       32
  53
  54 /* We need to address PTHREAD_KEYS_MAX key with PTHREAD_KEY_2NDLEVEL_SIZE
  55    keys in each subarray.  */
  56 #define PTHREAD_KEY_1STLEVEL_SIZE \
  57   ((PTHREAD_KEYS_MAX + PTHREAD_KEY_2NDLEVEL_SIZE - 1) \
  58    / PTHREAD_KEY_2NDLEVEL_SIZE)
  59
  60
  61
  62
  63 /* Internal version of the buffer to store cancellation handler
  64    information.  */
  65 struct pthread_unwind_buf
  66 {
  67   struct
  68   {
  69     __jmp_buf jmp_buf;
  70     int mask_was_saved;
  71   } cancel_jmp_buf[1];
  72
  73   union
  74   {
  75     /* This is the placeholder of the public version.  */
  76     void *pad[4];
  77
  78     struct
  79     {
  80       /* Pointer to the previous cleanup buffer.  */
  81       struct pthread_unwind_buf *prev;
  82
  83       /* Backward compatibility: state of the old-style cleanup
  84          handler at the time of the previous new-style cleanup handler
  85          installment.  */
  86       struct _pthread_cleanup_buffer *cleanup;
  87
  88       /* Cancellation type before the push call.  */
  89       int canceltype;
  90     } data;
  91   } priv;
  92 };
  93
  94
  95 /* Opcodes and data types for communication with the signal handler to
  96    change user/group IDs.  */
  97 struct xid_command
  98 {
  99   int syscall_no;
 100   long int id[3];
 101   volatile int cntr;
 102 };
 103
 104
 105 /* Data structure used by the kernel to find robust futexes.  */
 106 struct robust_list_head
 107 {
 108   void *list;
 109   long int futex_offset;
 110   void *list_op_pending;
 111 };
 112
 113
 114 /* Data strcture used to handle thread priority protection.  */
 115 struct priority_protection_data
 116 {
 117   int priomax;
 118   unsigned int priomap[];
 119 };
 120
 121
 122 /* Thread descriptor data structure.  */
 123 struct pthread
 124 {
 125   union
 126   {
 127 #if !defined(TLS_DTV_AT_TP)
 128     /* This overlaps the TCB as used for TLS without threads (see tls.h).  */
 129     tcbhead_t header;
 130 #else
 131     struct
 132     {
 133       int multiple_threads;
 134       int gscope_flag;
 135 # ifndef __ASSUME_PRIVATE_FUTEX
 136       int private_futex;
 137 # endif
 138     } header;
 139 #endif
 140
 141     /* This extra padding has no special purpose, and this structure layout
 142        is private and subject to change without affecting the official ABI.
 143        We just have it here in case it might be convenient for some
 144        implementation-specific instrumentation hack or suchlike.  */
 145     void *__padding[24];
 146   };
 147
 148   /* This descriptor's link on the `stack_used' or `__stack_user' list.  */
 149   list_t list;
 150
 151   /* Thread ID - which is also a 'is this thread descriptor (and
 152      therefore stack) used' flag.  */
 153   pid_t tid;
 154
 155   /* List of robust mutexes the thread is holding.  */
 156 #ifdef __PTHREAD_MUTEX_HAVE_PREV
 157   void *robust_prev;
 158   struct robust_list_head robust_head;
 159
 160   /* The list above is strange.  It is basically a double linked list
 161      but the pointer to the next/previous element of the list points
 162      in the middle of the object, the __next element.  Whenever
 163      casting to __pthread_list_t we need to adjust the pointer
 164      first.  */
 165 # define QUEUE_PTR_ADJUST (offsetof (__pthread_list_t, __next))
 166
 167 # define ENQUEUE_MUTEX_BOTH(mutex, val)                                       \
 168   do {                                                                        \
 169     __pthread_list_t *next = (__pthread_list_t *)                             \
 170       ((((uintptr_t) THREAD_GETMEM (THREAD_SELF, robust_head.list)) & ~1ul)   \
 171        - QUEUE_PTR_ADJUST);                                                   \
 172     next->__prev = (void *) &mutex->__data.__list.__next;                     \
 173     mutex->__data.__list.__next = THREAD_GETMEM (THREAD_SELF,                 \
 174                                                  robust_head.list);           \
 175     mutex->__data.__list.__prev = (void *) &THREAD_SELF->robust_head;         \
 176     THREAD_SETMEM (THREAD_SELF, robust_head.list,                             \
 177                    (void *) (((uintptr_t) &mutex->__data.__list.__next)       \
 178                              | val));                                         \
 179   } while (0)
 180 # define DEQUEUE_MUTEX(mutex) \
 181   do {                                                                        \
 182     __pthread_list_t *next = (__pthread_list_t *)                             \
 183       ((char *) (((uintptr_t) mutex->__data.__list.__next) & ~1ul)            \
 184        - QUEUE_PTR_ADJUST);                                                   \
 185     next->__prev = mutex->__data.__list.__prev;                               \
 186     __pthread_list_t *prev = (__pthread_list_t *)                             \
 187       ((char *) (((uintptr_t) mutex->__data.__list.__prev) & ~1ul)            \
 188        - QUEUE_PTR_ADJUST);                                                   \
 189     prev->__next = mutex->__data.__list.__next;                               \
 190     mutex->__data.__list.__prev = NULL;                                       \
 191     mutex->__data.__list.__next = NULL;                                       \
 192   } while (0)
 193 #else
 194   union
 195   {
 196     __pthread_slist_t robust_list;
 197     struct robust_list_head robust_head;
 198   };
 199
 200 # define ENQUEUE_MUTEX_BOTH(mutex, val)                                       \
 201   do {                                                                        \
 202     mutex->__data.__list.__next                                               \
 203       = THREAD_GETMEM (THREAD_SELF, robust_list.__next);                      \
 204     THREAD_SETMEM (THREAD_SELF, robust_list.__next,                           \
 205                    (void *) (((uintptr_t) &mutex->__data.__list) | val));     \
 206   } while (0)
 207 # define DEQUEUE_MUTEX(mutex) \
 208   do {                                                                        \
 209     __pthread_slist_t *runp = (__pthread_slist_t *)                           \
 210       (((uintptr_t) THREAD_GETMEM (THREAD_SELF, robust_list.__next)) & ~1ul); \
 211     if (runp == &mutex->__data.__list)                                        \
 212       THREAD_SETMEM (THREAD_SELF, robust_list.__next, runp->__next);          \
 213     else                                                                      \
 214       {                                                                       \
 215         __pthread_slist_t *next = (__pthread_slist_t *)               \
 216           (((uintptr_t) runp->__next) & ~1ul);                                \
 217         while (next != &mutex->__data.__list)                                 \
 218           {                                                                   \
 219             runp = next;                                                      \
 220             next = (__pthread_slist_t *) (((uintptr_t) runp->__next) & ~1ul); \
 221           }                                                                   \
 222                                                                               \
 223         runp->__next = next->__next;                                          \
 224         mutex->__data.__list.__next = NULL;                                   \
 225       }                                                                       \
 226   } while (0)
 227 #endif
 228 #define ENQUEUE_MUTEX(mutex) ENQUEUE_MUTEX_BOTH (mutex, 0)
 229 #define ENQUEUE_MUTEX_PI(mutex) ENQUEUE_MUTEX_BOTH (mutex, 1)
 230
 231   /* List of cleanup buffers.  */
 232   struct _pthread_cleanup_buffer *cleanup;
 233
 234   /* Unwind information.  */
 235   struct pthread_unwind_buf *cleanup_jmp_buf;
 236 #define HAVE_CLEANUP_JMP_BUF
 237
 238   /* Flags determining processing of cancellation.  */
 239   int cancelhandling;
 240   /* Bit set if cancellation is disabled.  */
 241 #define CANCELSTATE_BIT         0
 242 #define CANCELSTATE_BITMASK     (0x01 << CANCELSTATE_BIT)
 243   /* Bit set if asynchronous cancellation mode is selected.  */
 244 #define CANCELTYPE_BIT          1
 245 #define CANCELTYPE_BITMASK      (0x01 << CANCELTYPE_BIT)
 246   /* Bit set if canceling has been initiated.  */
 247 #define CANCELING_BIT           2
 248 #define CANCELING_BITMASK       (0x01 << CANCELING_BIT)
 249   /* Bit set if canceled.  */
 250 #define CANCELED_BIT            3
 251 #define CANCELED_BITMASK        (0x01 << CANCELED_BIT)
 252   /* Bit set if thread is exiting.  */
 253 #define EXITING_BIT             4
 254 #define EXITING_BITMASK         (0x01 << EXITING_BIT)
 255   /* Bit set if thread terminated and TCB is freed.  */
 256 #define TERMINATED_BIT          5
 257 #define TERMINATED_BITMASK      (0x01 << TERMINATED_BIT)
 258   /* Bit set if thread is supposed to change XID.  */
 259 #define SETXID_BIT              6
 260 #define SETXID_BITMASK          (0x01 << SETXID_BIT)
 261   /* Mask for the rest.  Helps the compiler to optimize.  */
 262 #define CANCEL_RESTMASK         0xffffff80
 263
 264 #define CANCEL_ENABLED_AND_CANCELED(value) \
 265   (((value) & (CANCELSTATE_BITMASK | CANCELED_BITMASK | EXITING_BITMASK       \
 266                | CANCEL_RESTMASK | TERMINATED_BITMASK)) == CANCELED_BITMASK)
 267 #define CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS(value) \
 268   (((value) & (CANCELSTATE_BITMASK | CANCELTYPE_BITMASK | CANCELED_BITMASK    \
 269                | EXITING_BITMASK | CANCEL_RESTMASK | TERMINATED_BITMASK))     \
 270    == (CANCELTYPE_BITMASK | CANCELED_BITMASK))
 271
 272   /* Flags.  Including those copied from the thread attribute.  */
 273   int flags;
 274
 275   /* We allocate one block of references here.  This should be enough
 276      to avoid allocating any memory dynamically for most applications.  */
 277   struct pthread_key_data
 278   {
 279     /* Sequence number.  We use uintptr_t to not require padding on
 280        32- and 64-bit machines.  On 64-bit machines it helps to avoid
 281        wrapping, too.  */
 282     uintptr_t seq;
 283
 284     /* Data pointer.  */
 285     void *data;
 286   } specific_1stblock[PTHREAD_KEY_2NDLEVEL_SIZE];
 287
 288   /* Two-level array for the thread-specific data.  */
 289   struct pthread_key_data *specific[PTHREAD_KEY_1STLEVEL_SIZE];
 290
 291   /* Flag which is set when specific data is set.  */
 292   bool specific_used;
 293
 294   /* True if events must be reported.  */
 295   bool report_events;
 296
 297   /* True if the user provided the stack.  */
 298   bool user_stack;
 299
 300   /* True if thread must stop at startup time.  */
 301   bool stopped_start;
 302
 303   /* The parent's cancel handling at the time of the pthread_create
 304      call.  This might be needed to undo the effects of a cancellation.  */
 305   int parent_cancelhandling;
 306
 307   /* Lock to synchronize access to the descriptor.  */
 308   int lock;
 309
 310   /* Lock for synchronizing setxid calls.  */
 311   int setxid_futex;
 312
 313 #if HP_TIMING_AVAIL
 314   /* Offset of the CPU clock at start thread start time.  */
 315   hp_timing_t cpuclock_offset;
 316 #endif
 317
 318   /* If the thread waits to join another one the ID of the latter is
 319      stored here.
 320
 321      In case a thread is detached this field contains a pointer of the
 322      TCB if the thread itself.  This is something which cannot happen
 323      in normal operation.  */
 324   struct pthread *joinid;
 325   /* Check whether a thread is detached.  */
 326 #define IS_DETACHED(pd) ((pd)->joinid == (pd))
 327
 328   /* The result of the thread function.  */
 329   void *result;
 330
 331   /* Scheduling parameters for the new thread.  */
 332   struct sched_param schedparam;
 333   int schedpolicy;
 334
 335   /* Start position of the code to be executed and the argument passed
 336      to the function.  */
 337   void *(*start_routine) (void *);
 338   void *arg;
 339
 340   /* Debug state.  */
 341   td_eventbuf_t eventbuf;
 342   /* Next descriptor with a pending event.  */
 343   struct pthread *nextevent;
 344
 345 #ifdef HAVE_FORCED_UNWIND
 346   /* Machine-specific unwind info.  */
 347   struct _Unwind_Exception exc;
 348 #endif
 349
 350   /* If nonzero pointer to area allocated for the stack and its
 351      size.  */
 352   void *stackblock;
 353   size_t stackblock_size;
 354   /* Size of the included guard area.  */
 355   size_t guardsize;
 356   /* This is what the user specified and what we will report.  */
 357   size_t reported_guardsize;
 358
 359   /* Thread Priority Protection data.  */
 360   struct priority_protection_data *tpp;
 361
 362   /* Resolver state.  */
 363   struct __res_state res;
 364
 365   /* This member must be last.  */
 366   char end_padding[];
 367
 368 #define PTHREAD_STRUCT_END_PADDING \
 369   (sizeof (struct pthread) - offsetof (struct pthread, end_padding))
 370 } __attribute ((aligned (TCB_ALIGNMENT)));
 371
 372
 373 #endif  /* descr.h */