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