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. */
64struct 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. */
96struct 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. */
106struct 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. */
115struct priority_protection_data
116{
117 int priomax;
118 unsigned int priomap[];
119};
120
121
122/* Thread descriptor data structure. */
123struct 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 */
390