nptl/descr.h

   1 /* Copyright (C) 2002-2016 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 #include <unwind.h>
  36 #define __need_res_state
  37 #include <resolv.h>
  38 #include <kernel-features.h>
  39
  40 #ifndef TCB_ALIGNMENT
  41 # define TCB_ALIGNMENT  sizeof (double)
  42 #endif
  43
  44
  45 /* We keep thread specific data in a special data structure, a two-level
  46    array.  The top-level array contains pointers to dynamically allocated
  47    arrays of a certain number of data pointers.  So we can implement a
  48    sparse array.  Each dynamic second-level array has
  49         PTHREAD_KEY_2NDLEVEL_SIZE
  50    entries.  This value shouldn't be too large.  */
  51 #define PTHREAD_KEY_2NDLEVEL_SIZE       32
  52
  53 /* We need to address PTHREAD_KEYS_MAX key with PTHREAD_KEY_2NDLEVEL_SIZE
  54    keys in each subarray.  */
  55 #define PTHREAD_KEY_1STLEVEL_SIZE \
  56   ((PTHREAD_KEYS_MAX + PTHREAD_KEY_2NDLEVEL_SIZE - 1) \
  57    / PTHREAD_KEY_2NDLEVEL_SIZE)
  58
  59
  60
  61
  62 /* Internal version of the buffer to store cancellation handler
  63    information.  */
  64 struct pthread_unwind_buf
  65 {
  66   struct
  67   {
  68     __jmp_buf jmp_buf;
  69     int mask_was_saved;
  70   } cancel_jmp_buf[1];
  71
  72   union
  73   {
  74     /* This is the placeholder of the public version.  */
  75     void *pad[4];
  76
  77     struct
  78     {
  79       /* Pointer to the previous cleanup buffer.  */
  80       struct pthread_unwind_buf *prev;
  81
  82       /* Backward compatibility: state of the old-style cleanup
  83          handler at the time of the previous new-style cleanup handler
  84          installment.  */
  85       struct _pthread_cleanup_buffer *cleanup;
  86
  87       /* Cancellation type before the push call.  */
  88       int canceltype;
  89     } data;
  90   } priv;
  91 };
  92
  93
  94 /* Opcodes and data types for communication with the signal handler to
  95    change user/group IDs.  */
  96 struct xid_command
  97 {
  98   int syscall_no;
  99   long int id[3];
 100   volatile int cntr;
 101   volatile int error; /* -1: no call yet, 0: success seen, >0: error seen.  */
 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       /* multiple_threads is enabled either when the process has spawned at
 134          least one thread or when a single-threaded process cancels itself.
 135          This enables additional code to introduce locking before doing some
 136          compare_and_exchange operations and also enable cancellation points.
 137          The concepts of multiple threads and cancellation points ideally
 138          should be separate, since it is not necessary for multiple threads to
 139          have been created for cancellation points to be enabled, as is the
 140          case is when single-threaded process cancels itself.
 141
 142          Since enabling multiple_threads enables additional code in
 143          cancellation points and compare_and_exchange operations, there is a
 144          potential for an unneeded performance hit when it is enabled in a
 145          single-threaded, self-canceling process.  This is OK though, since a
 146          single-threaded process will enable async cancellation only when it
 147          looks to cancel itself and is hence going to end anyway.  */
 148       int multiple_threads;
 149       int gscope_flag;
 150 # ifndef __ASSUME_PRIVATE_FUTEX
 151       int private_futex;
 152 # endif
 153     } header;
 154 #endif
 155
 156     /* This extra padding has no special purpose, and this structure layout
 157        is private and subject to change without affecting the official ABI.
 158        We just have it here in case it might be convenient for some
 159        implementation-specific instrumentation hack or suchlike.  */
 160     void *__padding[24];
 161   };
 162
 163   /* This descriptor's link on the `stack_used' or `__stack_user' list.  */
 164   list_t list;
 165
 166   /* Thread ID - which is also a 'is this thread descriptor (and
 167      therefore stack) used' flag.  */
 168   pid_t tid;
 169
 170   /* Process ID - thread group ID in kernel speak.  */
 171   pid_t pid;
 172
 173   /* List of robust mutexes the thread is holding.  */
 174 #ifdef __PTHREAD_MUTEX_HAVE_PREV
 175   void *robust_prev;
 176   struct robust_list_head robust_head;
 177
 178   /* The list above is strange.  It is basically a double linked list
 179      but the pointer to the next/previous element of the list points
 180      in the middle of the object, the __next element.  Whenever
 181      casting to __pthread_list_t we need to adjust the pointer
 182      first.  */
 183 # define QUEUE_PTR_ADJUST (offsetof (__pthread_list_t, __next))
 184
 185 # define ENQUEUE_MUTEX_BOTH(mutex, val)                                       \
 186   do {                                                                        \
 187     __pthread_list_t *next = (__pthread_list_t *)                             \
 188       ((((uintptr_t) THREAD_GETMEM (THREAD_SELF, robust_head.list)) & ~1ul)   \
 189        - QUEUE_PTR_ADJUST);                                                   \
 190     next->__prev = (void *) &mutex->__data.__list.__next;                     \
 191     mutex->__data.__list.__next = THREAD_GETMEM (THREAD_SELF,                 \
 192                                                  robust_head.list);           \
 193     mutex->__data.__list.__prev = (void *) &THREAD_SELF->robust_head;         \
 194     THREAD_SETMEM (THREAD_SELF, robust_head.list,                             \
 195                    (void *) (((uintptr_t) &mutex->__data.__list.__next)       \
 196                              | val));                                         \
 197   } while (0)
 198 # define DEQUEUE_MUTEX(mutex) \
 199   do {                                                                        \
 200     __pthread_list_t *next = (__pthread_list_t *)                             \
 201       ((char *) (((uintptr_t) mutex->__data.__list.__next) & ~1ul)            \
 202        - QUEUE_PTR_ADJUST);                                                   \
 203     next->__prev = mutex->__data.__list.__prev;                               \
 204     __pthread_list_t *prev = (__pthread_list_t *)                             \
 205       ((char *) (((uintptr_t) mutex->__data.__list.__prev) & ~1ul)            \
 206        - QUEUE_PTR_ADJUST);                                                   \
 207     prev->__next = mutex->__data.__list.__next;                               \
 208     mutex->__data.__list.__prev = NULL;                                       \
 209     mutex->__data.__list.__next = NULL;                                       \
 210   } while (0)
 211 #else
 212   union
 213   {
 214     __pthread_slist_t robust_list;
 215     struct robust_list_head robust_head;
 216   };
 217
 218 # define ENQUEUE_MUTEX_BOTH(mutex, val)                                       \
 219   do {                                                                        \
 220     mutex->__data.__list.__next                                               \
 221       = THREAD_GETMEM (THREAD_SELF, robust_list.__next);                      \
 222     THREAD_SETMEM (THREAD_SELF, robust_list.__next,                           \
 223                    (void *) (((uintptr_t) &mutex->__data.__list) | val));     \
 224   } while (0)
 225 # define DEQUEUE_MUTEX(mutex) \
 226   do {                                                                        \
 227     __pthread_slist_t *runp = (__pthread_slist_t *)                           \
 228       (((uintptr_t) THREAD_GETMEM (THREAD_SELF, robust_list.__next)) & ~1ul); \
 229     if (runp == &mutex->__data.__list)                                        \
 230       THREAD_SETMEM (THREAD_SELF, robust_list.__next, runp->__next);          \
 231     else                                                                      \
 232       {                                                                       \
 233         __pthread_slist_t *next = (__pthread_slist_t *)               \
 234           (((uintptr_t) runp->__next) & ~1ul);                                \
 235         while (next != &mutex->__data.__list)                                 \
 236           {                                                                   \
 237             runp = next;                                                      \
 238             next = (__pthread_slist_t *) (((uintptr_t) runp->__next) & ~1ul); \
 239           }                                                                   \
 240                                                                               \
 241         runp->__next = next->__next;                                          \
 242         mutex->__data.__list.__next = NULL;                                   \
 243       }                                                                       \
 244   } while (0)
 245 #endif
 246 #define ENQUEUE_MUTEX(mutex) ENQUEUE_MUTEX_BOTH (mutex, 0)
 247 #define ENQUEUE_MUTEX_PI(mutex) ENQUEUE_MUTEX_BOTH (mutex, 1)
 248
 249   /* List of cleanup buffers.  */
 250   struct _pthread_cleanup_buffer *cleanup;
 251
 252   /* Unwind information.  */
 253   struct pthread_unwind_buf *cleanup_jmp_buf;
 254 #define HAVE_CLEANUP_JMP_BUF
 255
 256   /* Flags determining processing of cancellation.  */
 257   int cancelhandling;
 258   /* Bit set if cancellation is disabled.  */
 259 #define CANCELSTATE_BIT         0
 260 #define CANCELSTATE_BITMASK     (0x01 << CANCELSTATE_BIT)
 261   /* Bit set if asynchronous cancellation mode is selected.  */
 262 #define CANCELTYPE_BIT          1
 263 #define CANCELTYPE_BITMASK      (0x01 << CANCELTYPE_BIT)
 264   /* Bit set if canceling has been initiated.  */
 265 #define CANCELING_BIT           2
 266 #define CANCELING_BITMASK       (0x01 << CANCELING_BIT)
 267   /* Bit set if canceled.  */
 268 #define CANCELED_BIT            3
 269 #define CANCELED_BITMASK        (0x01 << CANCELED_BIT)
 270   /* Bit set if thread is exiting.  */
 271 #define EXITING_BIT             4
 272 #define EXITING_BITMASK         (0x01 << EXITING_BIT)
 273   /* Bit set if thread terminated and TCB is freed.  */
 274 #define TERMINATED_BIT          5
 275 #define TERMINATED_BITMASK      (0x01 << TERMINATED_BIT)
 276   /* Bit set if thread is supposed to change XID.  */
 277 #define SETXID_BIT              6
 278 #define SETXID_BITMASK          (0x01 << SETXID_BIT)
 279   /* Mask for the rest.  Helps the compiler to optimize.  */
 280 #define CANCEL_RESTMASK         0xffffff80
 281
 282 #define CANCEL_ENABLED_AND_CANCELED(value) \
 283   (((value) & (CANCELSTATE_BITMASK | CANCELED_BITMASK | EXITING_BITMASK       \
 284                | CANCEL_RESTMASK | TERMINATED_BITMASK)) == CANCELED_BITMASK)
 285 #define CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS(value) \
 286   (((value) & (CANCELSTATE_BITMASK | CANCELTYPE_BITMASK | CANCELED_BITMASK    \
 287                | EXITING_BITMASK | CANCEL_RESTMASK | TERMINATED_BITMASK))     \
 288    == (CANCELTYPE_BITMASK | CANCELED_BITMASK))
 289
 290   /* Flags.  Including those copied from the thread attribute.  */
 291   int flags;
 292
 293   /* We allocate one block of references here.  This should be enough
 294      to avoid allocating any memory dynamically for most applications.  */
 295   struct pthread_key_data
 296   {
 297     /* Sequence number.  We use uintptr_t to not require padding on
 298        32- and 64-bit machines.  On 64-bit machines it helps to avoid
 299        wrapping, too.  */
 300     uintptr_t seq;
 301
 302     /* Data pointer.  */
 303     void *data;
 304   } specific_1stblock[PTHREAD_KEY_2NDLEVEL_SIZE];
 305
 306   /* Two-level array for the thread-specific data.  */
 307   struct pthread_key_data *specific[PTHREAD_KEY_1STLEVEL_SIZE];
 308
 309   /* Flag which is set when specific data is set.  */
 310   bool specific_used;
 311
 312   /* True if events must be reported.  */
 313   bool report_events;
 314
 315   /* True if the user provided the stack.  */
 316   bool user_stack;
 317
 318   /* True if thread must stop at startup time.  */
 319   bool stopped_start;
 320
 321   /* The parent's cancel handling at the time of the pthread_create
 322      call.  This might be needed to undo the effects of a cancellation.  */
 323   int parent_cancelhandling;
 324
 325   /* Lock to synchronize access to the descriptor.  */
 326   int lock;
 327
 328   /* Lock for synchronizing setxid calls.  */
 329   unsigned int setxid_futex;
 330
 331 #if HP_TIMING_AVAIL
 332   /* Offset of the CPU clock at start thread start time.  */
 333   hp_timing_t cpuclock_offset;
 334 #endif
 335
 336   /* If the thread waits to join another one the ID of the latter is
 337      stored here.
 338
 339      In case a thread is detached this field contains a pointer of the
 340      TCB if the thread itself.  This is something which cannot happen
 341      in normal operation.  */
 342   struct pthread *joinid;
 343   /* Check whether a thread is detached.  */
 344 #define IS_DETACHED(pd) ((pd)->joinid == (pd))
 345
 346   /* The result of the thread function.  */
 347   void *result;
 348
 349   /* Scheduling parameters for the new thread.  */
 350   struct sched_param schedparam;
 351   int schedpolicy;
 352
 353   /* Start position of the code to be executed and the argument passed
 354      to the function.  */
 355   void *(*start_routine) (void *);
 356   void *arg;
 357
 358   /* Debug state.  */
 359   td_eventbuf_t eventbuf;
 360   /* Next descriptor with a pending event.  */
 361   struct pthread *nextevent;
 362
 363   /* Machine-specific unwind info.  */
 364   struct _Unwind_Exception exc;
 365
 366   /* If nonzero pointer to area allocated for the stack and its
 367      size.  */
 368   void *stackblock;
 369   size_t stackblock_size;
 370   /* Size of the included guard area.  */
 371   size_t guardsize;
 372   /* This is what the user specified and what we will report.  */
 373   size_t reported_guardsize;
 374
 375   /* Thread Priority Protection data.  */
 376   struct priority_protection_data *tpp;
 377
 378   /* Resolver state.  */
 379   struct __res_state res;
 380
 381   /* This member must be last.  */
 382   char end_padding[];
 383
 384 #define PTHREAD_STRUCT_END_PADDING \
 385   (sizeof (struct pthread) - offsetof (struct pthread, end_padding))
 386 } __attribute ((aligned (TCB_ALIGNMENT)));
 387
 388
 389 #endif  /* descr.h */