nptl/descr.h

   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 #ifndef _DESCR_H
  21 #define _DESCR_H        1
  22
  23 #include <limits.h>
  24 #include <sched.h>
  25 #include <setjmp.h>
  26 #include <stdbool.h>
  27 #include <sys/types.h>
  28 #include <hp-timing.h>
  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
  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 /* Thread descriptor data structure.  */
 115 struct pthread
 116 {
 117   union
 118   {
 119 #if !TLS_DTV_AT_TP
 120     /* This overlaps the TCB as used for TLS without threads (see tls.h).  */
 121     tcbhead_t header;
 122 #else
 123     struct
 124     {
 125       int multiple_threads;
 126     } header;
 127 #endif
 128
 129     /* This extra padding has no special purpose, and this structure layout
 130        is private and subject to change without affecting the official ABI.
 131        We just have it here in case it might be convenient for some
 132        implementation-specific instrumentation hack or suchlike.  */
 133     void *__padding[16];
 134   };
 135
 136   /* This descriptor's link on the `stack_used' or `__stack_user' list.  */
 137   list_t list;
 138
 139   /* Thread ID - which is also a 'is this thread descriptor (and
 140      therefore stack) used' flag.  */
 141   pid_t tid;
 142
 143   /* Process ID - thread group ID in kernel speak.  */
 144   pid_t pid;
 145
 146   /* List of robust mutexes the thread is holding.  */
 147 #ifdef __PTHREAD_MUTEX_HAVE_PREV
 148   void *robust_prev;
 149   struct robust_list_head robust_head;
 150
 151   /* The list above is strange.  It is basically a double linked list
 152      but the pointer to the next/previous element of the list points
 153      in the middle of the object, the __next element.  Whenever
 154      casting to __pthread_list_t we need to adjust the pointer
 155      first.  */
 156 # define QUEUE_PTR_ADJUST (offsetof (__pthread_list_t, __next))
 157
 158 # define ENQUEUE_MUTEX(mutex) \
 159   do {                                                                        \
 160     __pthread_list_t *next = (THREAD_GETMEM (THREAD_SELF, robust_head.list)   \
 161                               - QUEUE_PTR_ADJUST);                            \
 162     next->__prev = (void *) &mutex->__data.__list.__next;                     \
 163     mutex->__data.__list.__next = (void *) &next->__next;                     \
 164     mutex->__data.__list.__prev = (void *) &THREAD_SELF->robust_head;         \
 165     THREAD_SETMEM (THREAD_SELF, robust_head.list,                             \
 166                    &mutex->__data.__list.__next);                             \
 167   } while (0)
 168 # define DEQUEUE_MUTEX(mutex) \
 169   do {                                                                        \
 170     __pthread_list_t *next = (__pthread_list_t *)                             \
 171       ((char *) mutex->__data.__list.__next - QUEUE_PTR_ADJUST);              \
 172     next->__prev = mutex->__data.__list.__prev;                               \
 173     __pthread_list_t *prev = (__pthread_list_t *)                             \
 174       ((char *) mutex->__data.__list.__prev - QUEUE_PTR_ADJUST);              \
 175     prev->__next = mutex->__data.__list.__next;                               \
 176     mutex->__data.__list.__prev = NULL;                                       \
 177     mutex->__data.__list.__next = NULL;                                       \
 178   } while (0)
 179 #else
 180   union
 181   {
 182     __pthread_slist_t robust_list;
 183     struct robust_list_head robust_head;
 184   };
 185
 186 # define ENQUEUE_MUTEX(mutex) \
 187   do {                                                                        \
 188     mutex->__data.__list.__next                                               \
 189       = THREAD_GETMEM (THREAD_SELF, robust_list.__next);                      \
 190     THREAD_SETMEM (THREAD_SELF, robust_list.__next, &mutex->__data.__list);   \
 191   } while (0)
 192 # define DEQUEUE_MUTEX(mutex) \
 193   do {                                                                        \
 194     __pthread_slist_t *runp = THREAD_GETMEM (THREAD_SELF, robust_list.__next);\
 195     if (runp == &mutex->__data.__list)                                        \
 196       THREAD_SETMEM (THREAD_SELF, robust_list.__next, runp->__next);          \
 197     else                                                                      \
 198       {                                                                       \
 199         while (runp->__next != &mutex->__data.__list)                         \
 200           runp = runp->__next;                                                \
 201                                                                               \
 202         runp->__next = runp->__next->__next;                                  \
 203         mutex->__data.__list.__next = NULL;                                   \
 204       }                                                                       \
 205   } while (0)
 206 #endif
 207
 208   /* List of cleanup buffers.  */
 209   struct _pthread_cleanup_buffer *cleanup;
 210
 211   /* Unwind information.  */
 212   struct pthread_unwind_buf *cleanup_jmp_buf;
 213 #define HAVE_CLEANUP_JMP_BUF
 214
 215   /* Flags determining processing of cancellation.  */
 216   int cancelhandling;
 217   /* Bit set if cancellation is disabled.  */
 218 #define CANCELSTATE_BIT         0
 219 #define CANCELSTATE_BITMASK     0x01
 220   /* Bit set if asynchronous cancellation mode is selected.  */
 221 #define CANCELTYPE_BIT          1
 222 #define CANCELTYPE_BITMASK      0x02
 223   /* Bit set if canceling has been initiated.  */
 224 #define CANCELING_BIT           2
 225 #define CANCELING_BITMASK       0x04
 226   /* Bit set if canceled.  */
 227 #define CANCELED_BIT            3
 228 #define CANCELED_BITMASK        0x08
 229   /* Bit set if thread is exiting.  */
 230 #define EXITING_BIT             4
 231 #define EXITING_BITMASK         0x10
 232   /* Bit set if thread terminated and TCB is freed.  */
 233 #define TERMINATED_BIT          5
 234 #define TERMINATED_BITMASK      0x20
 235   /* Bit set if thread is supposed to change XID.  */
 236 #define SETXID_BIT              6
 237 #define SETXID_BITMASK          0x40
 238   /* Mask for the rest.  Helps the compiler to optimize.  */
 239 #define CANCEL_RESTMASK         0xffffff80
 240
 241 #define CANCEL_ENABLED_AND_CANCELED(value) \
 242   (((value) & (CANCELSTATE_BITMASK | CANCELED_BITMASK | EXITING_BITMASK       \
 243                | CANCEL_RESTMASK | TERMINATED_BITMASK)) == CANCELED_BITMASK)
 244 #define CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS(value) \
 245   (((value) & (CANCELSTATE_BITMASK | CANCELTYPE_BITMASK | CANCELED_BITMASK    \
 246                | EXITING_BITMASK | CANCEL_RESTMASK | TERMINATED_BITMASK))     \
 247    == (CANCELTYPE_BITMASK | CANCELED_BITMASK))
 248
 249   /* We allocate one block of references here.  This should be enough
 250      to avoid allocating any memory dynamically for most applications.  */
 251   struct pthread_key_data
 252   {
 253     /* Sequence number.  We use uintptr_t to not require padding on
 254        32- and 64-bit machines.  On 64-bit machines it helps to avoid
 255        wrapping, too.  */
 256     uintptr_t seq;
 257
 258     /* Data pointer.  */
 259     void *data;
 260   } specific_1stblock[PTHREAD_KEY_2NDLEVEL_SIZE];
 261
 262   /* Two-level array for the thread-specific data.  */
 263   struct pthread_key_data *specific[PTHREAD_KEY_1STLEVEL_SIZE];
 264
 265   /* Flag which is set when specific data is set.  */
 266   bool specific_used;
 267
 268   /* True if events must be reported.  */
 269   bool report_events;
 270
 271   /* True if the user provided the stack.  */
 272   bool user_stack;
 273
 274   /* True if thread must stop at startup time.  */
 275   bool stopped_start;
 276
 277   /* Lock to synchronize access to the descriptor.  */
 278   lll_lock_t lock;
 279
 280   /* Lock for synchronizing setxid calls.  */
 281   lll_lock_t setxid_futex;
 282
 283 #if HP_TIMING_AVAIL
 284   /* Offset of the CPU clock at start thread start time.  */
 285   hp_timing_t cpuclock_offset;
 286 #endif
 287
 288   /* If the thread waits to join another one the ID of the latter is
 289      stored here.
 290
 291      In case a thread is detached this field contains a pointer of the
 292      TCB if the thread itself.  This is something which cannot happen
 293      in normal operation.  */
 294   struct pthread *joinid;
 295   /* Check whether a thread is detached.  */
 296 #define IS_DETACHED(pd) ((pd)->joinid == (pd))
 297
 298   /* Flags.  Including those copied from the thread attribute.  */
 299   int flags;
 300
 301   /* The result of the thread function.  */
 302   void *result;
 303
 304   /* Scheduling parameters for the new thread.  */
 305   struct sched_param schedparam;
 306   int schedpolicy;
 307
 308   /* Start position of the code to be executed and the argument passed
 309      to the function.  */
 310   void *(*start_routine) (void *);
 311   void *arg;
 312
 313   /* Debug state.  */
 314   td_eventbuf_t eventbuf;
 315   /* Next descriptor with a pending event.  */
 316   struct pthread *nextevent;
 317
 318 #ifdef HAVE_FORCED_UNWIND
 319   /* Machine-specific unwind info.  */
 320   struct _Unwind_Exception exc;
 321 #endif
 322
 323   /* If nonzero pointer to area allocated for the stack and its
 324      size.  */
 325   void *stackblock;
 326   size_t stackblock_size;
 327   /* Size of the included guard area.  */
 328   size_t guardsize;
 329   /* This is what the user specified and what we will report.  */
 330   size_t reported_guardsize;
 331
 332   /* Resolver state.  */
 333   struct __res_state res;
 334
 335   /* This member must be last.  */
 336   char end_padding[];
 337
 338 #define PTHREAD_STRUCT_END_PADDING \
 339   (sizeof (struct pthread) - offsetof (struct pthread, end_padding))
 340 } __attribute ((aligned (TCB_ALIGNMENT)));
 341
 342
 343 #endif  /* descr.h */