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 /* 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 !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     } header;
 135 #endif
 136
 137     /* This extra padding has no special purpose, and this structure layout
 138        is private and subject to change without affecting the official ABI.
 139        We just have it here in case it might be convenient for some
 140        implementation-specific instrumentation hack or suchlike.  */
 141     void *__padding[16];
 142   };
 143
 144   /* This descriptor's link on the `stack_used' or `__stack_user' list.  */
 145   list_t list;
 146
 147   /* Thread ID - which is also a 'is this thread descriptor (and
 148      therefore stack) used' flag.  */
 149   pid_t tid;
 150
 151   /* Process ID - thread group ID in kernel speak.  */
 152   pid_t pid;
 153
 154   /* List of robust mutexes the thread is holding.  */
 155 #ifdef __PTHREAD_MUTEX_HAVE_PREV
 156   void *robust_prev;
 157   struct robust_list_head robust_head;
 158
 159   /* The list above is strange.  It is basically a double linked list
 160      but the pointer to the next/previous element of the list points
 161      in the middle of the object, the __next element.  Whenever
 162      casting to __pthread_list_t we need to adjust the pointer
 163      first.  */
 164 # define QUEUE_PTR_ADJUST (offsetof (__pthread_list_t, __next))
 165
 166 # define ENQUEUE_MUTEX_BOTH(mutex, val)                                       \
 167   do {                                                                        \
 168     __pthread_list_t *next = (__pthread_list_t *)                             \
 169       ((((uintptr_t) THREAD_GETMEM (THREAD_SELF, robust_head.list)) & ~1ul)   \
 170        - QUEUE_PTR_ADJUST);                                                   \
 171     next->__prev = (void *) &mutex->__data.__list.__next;                     \
 172     mutex->__data.__list.__next = THREAD_GETMEM (THREAD_SELF,                 \
 173                                                  robust_head.list);           \
 174     mutex->__data.__list.__prev = (void *) &THREAD_SELF->robust_head;         \
 175     THREAD_SETMEM (THREAD_SELF, robust_head.list,                             \
 176                    (void *) (((uintptr_t) &mutex->__data.__list.__next)       \
 177                              | val));                                         \
 178   } while (0)
 179 # define DEQUEUE_MUTEX(mutex) \
 180   do {                                                                        \
 181     __pthread_list_t *next = (__pthread_list_t *)                             \
 182       ((char *) (((uintptr_t) mutex->__data.__list.__next) & ~1ul)            \
 183        - QUEUE_PTR_ADJUST);                                                   \
 184     next->__prev = mutex->__data.__list.__prev;                               \
 185     __pthread_list_t *prev = (__pthread_list_t *)                             \
 186       ((char *) (((uintptr_t) mutex->__data.__list.__prev) & ~1ul)            \
 187        - QUEUE_PTR_ADJUST);                                                   \
 188     prev->__next = mutex->__data.__list.__next;                               \
 189     mutex->__data.__list.__prev = NULL;                                       \
 190     mutex->__data.__list.__next = NULL;                                       \
 191   } while (0)
 192 #else
 193   union
 194   {
 195     __pthread_slist_t robust_list;
 196     struct robust_list_head robust_head;
 197   };
 198
 199 # define ENQUEUE_MUTEX_BOTH(mutex, val)                                       \
 200   do {                                                                        \
 201     mutex->__data.__list.__next                                               \
 202       = THREAD_GETMEM (THREAD_SELF, robust_list.__next);                      \
 203     THREAD_SETMEM (THREAD_SELF, robust_list.__next,                           \
 204                    (void *) (((uintptr_t) &mutex->__data.__list) | val));     \
 205   } while (0)
 206 # define DEQUEUE_MUTEX(mutex) \
 207   do {                                                                        \
 208     __pthread_slist_t *runp = (__pthread_slist_t *)                           \
 209       (((uintptr_t) THREAD_GETMEM (THREAD_SELF, robust_list.__next)) & ~1ul); \
 210     if (runp == &mutex->__data.__list)                                        \
 211       THREAD_SETMEM (THREAD_SELF, robust_list.__next, runp->__next);          \
 212     else                                                                      \
 213       {                                                                       \
 214         __pthread_slist_t *next = (__pthread_slist_t *)               \
 215           (((uintptr_t) runp->__next) & ~1ul);                                \
 216         while (next != &mutex->__data.__list)                                 \
 217           {                                                                   \
 218             runp = next;                                                      \
 219             next = (__pthread_slist_t *) (((uintptr_t) runp->__next) & ~1ul); \
 220           }                                                                   \
 221                                                                               \
 222         runp->__next = next->__next;                                          \
 223         mutex->__data.__list.__next = NULL;                                   \
 224       }                                                                       \
 225   } while (0)
 226 #endif
 227 #define ENQUEUE_MUTEX(mutex) ENQUEUE_MUTEX_BOTH (mutex, 0)
 228 #define ENQUEUE_MUTEX_PI(mutex) ENQUEUE_MUTEX_BOTH (mutex, 1)
 229
 230   /* List of cleanup buffers.  */
 231   struct _pthread_cleanup_buffer *cleanup;
 232
 233   /* Unwind information.  */
 234   struct pthread_unwind_buf *cleanup_jmp_buf;
 235 #define HAVE_CLEANUP_JMP_BUF
 236
 237   /* Flags determining processing of cancellation.  */
 238   int cancelhandling;
 239   /* Bit set if cancellation is disabled.  */
 240 #define CANCELSTATE_BIT         0
 241 #define CANCELSTATE_BITMASK     0x01
 242   /* Bit set if asynchronous cancellation mode is selected.  */
 243 #define CANCELTYPE_BIT          1
 244 #define CANCELTYPE_BITMASK      0x02
 245   /* Bit set if canceling has been initiated.  */
 246 #define CANCELING_BIT           2
 247 #define CANCELING_BITMASK       0x04
 248   /* Bit set if canceled.  */
 249 #define CANCELED_BIT            3
 250 #define CANCELED_BITMASK        0x08
 251   /* Bit set if thread is exiting.  */
 252 #define EXITING_BIT             4
 253 #define EXITING_BITMASK         0x10
 254   /* Bit set if thread terminated and TCB is freed.  */
 255 #define TERMINATED_BIT          5
 256 #define TERMINATED_BITMASK      0x20
 257   /* Bit set if thread is supposed to change XID.  */
 258 #define SETXID_BIT              6
 259 #define SETXID_BITMASK          0x40
 260   /* Mask for the rest.  Helps the compiler to optimize.  */
 261 #define CANCEL_RESTMASK         0xffffff80
 262
 263 #define CANCEL_ENABLED_AND_CANCELED(value) \
 264   (((value) & (CANCELSTATE_BITMASK | CANCELED_BITMASK | EXITING_BITMASK       \
 265                | CANCEL_RESTMASK | TERMINATED_BITMASK)) == CANCELED_BITMASK)
 266 #define CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS(value) \
 267   (((value) & (CANCELSTATE_BITMASK | CANCELTYPE_BITMASK | CANCELED_BITMASK    \
 268                | EXITING_BITMASK | CANCEL_RESTMASK | TERMINATED_BITMASK))     \
 269    == (CANCELTYPE_BITMASK | CANCELED_BITMASK))
 270
 271   /* We allocate one block of references here.  This should be enough
 272      to avoid allocating any memory dynamically for most applications.  */
 273   struct pthread_key_data
 274   {
 275     /* Sequence number.  We use uintptr_t to not require padding on
 276        32- and 64-bit machines.  On 64-bit machines it helps to avoid
 277        wrapping, too.  */
 278     uintptr_t seq;
 279
 280     /* Data pointer.  */
 281     void *data;
 282   } specific_1stblock[PTHREAD_KEY_2NDLEVEL_SIZE];
 283
 284   /* Two-level array for the thread-specific data.  */
 285   struct pthread_key_data *specific[PTHREAD_KEY_1STLEVEL_SIZE];
 286
 287   /* Flag which is set when specific data is set.  */
 288   bool specific_used;
 289
 290   /* True if events must be reported.  */
 291   bool report_events;
 292
 293   /* True if the user provided the stack.  */
 294   bool user_stack;
 295
 296   /* True if thread must stop at startup time.  */
 297   bool stopped_start;
 298
 299   /* The parent's cancel handling at the time of the pthread_create
 300      call.  This might be needed to undo the effects of a cancellation.  */
 301   int parent_cancelhandling;
 302
 303   /* Lock to synchronize access to the descriptor.  */
 304   lll_lock_t lock;
 305
 306   /* Lock for synchronizing setxid calls.  */
 307   lll_lock_t setxid_futex;
 308
 309 #if HP_TIMING_AVAIL
 310   /* Offset of the CPU clock at start thread start time.  */
 311   hp_timing_t cpuclock_offset;
 312 #endif
 313
 314   /* If the thread waits to join another one the ID of the latter is
 315      stored here.
 316
 317      In case a thread is detached this field contains a pointer of the
 318      TCB if the thread itself.  This is something which cannot happen
 319      in normal operation.  */
 320   struct pthread *joinid;
 321   /* Check whether a thread is detached.  */
 322 #define IS_DETACHED(pd) ((pd)->joinid == (pd))
 323
 324   /* Flags.  Including those copied from the thread attribute.  */
 325   int flags;
 326
 327   /* The result of the thread function.  */
 328   void *result;
 329
 330   /* Scheduling parameters for the new thread.  */
 331   struct sched_param schedparam;
 332   int schedpolicy;
 333
 334   /* Start position of the code to be executed and the argument passed
 335      to the function.  */
 336   void *(*start_routine) (void *);
 337   void *arg;
 338
 339   /* Debug state.  */
 340   td_eventbuf_t eventbuf;
 341   /* Next descriptor with a pending event.  */
 342   struct pthread *nextevent;
 343
 344 #ifdef HAVE_FORCED_UNWIND
 345   /* Machine-specific unwind info.  */
 346   struct _Unwind_Exception exc;
 347 #endif
 348
 349   /* If nonzero pointer to area allocated for the stack and its
 350      size.  */
 351   void *stackblock;
 352   size_t stackblock_size;
 353   /* Size of the included guard area.  */
 354   size_t guardsize;
 355   /* This is what the user specified and what we will report.  */
 356   size_t reported_guardsize;
 357
 358   /* Thread Priority Protection data.  */
 359   struct priority_protection_data *tpp;
 360
 361   /* Resolver state.  */
 362   struct __res_state res;
 363
 364   /* This member must be last.  */
 365   char end_padding[];
 366
 367 #define PTHREAD_STRUCT_END_PADDING \
 368   (sizeof (struct pthread) - offsetof (struct pthread, end_padding))
 369 } __attribute ((aligned (TCB_ALIGNMENT)));
 370
 371
 372 #endif  /* descr.h */