1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *  * Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *  * Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in
12 *    the documentation and/or other materials provided with the
13 *    distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#pragma once
30
31#include <pthread.h>
32#include <stdatomic.h>
33
34#include "private/bionic_lock.h"
35#include "private/bionic_tls.h"
36
37// Has the thread been detached by a pthread_join or pthread_detach call?
38#define PTHREAD_ATTR_FLAG_DETACHED 0x00000001
39
40// Has the thread been joined by another thread?
41#define PTHREAD_ATTR_FLAG_JOINED 0x00000002
42
43// Used for pthread_attr_setinheritsched. We need two flags for this apparent
44// boolean because our historical behavior matches neither of the POSIX choices.
45#define PTHREAD_ATTR_FLAG_INHERIT 0x00000004
46#define PTHREAD_ATTR_FLAG_EXPLICIT 0x00000008
47
48class pthread_key_data_t {
49 public:
50  uintptr_t seq; // Use uintptr_t just for alignment, as we use pointer below.
51  void* data;
52};
53
54enum ThreadJoinState {
55  THREAD_NOT_JOINED,
56  THREAD_EXITED_NOT_JOINED,
57  THREAD_JOINED,
58  THREAD_DETACHED
59};
60
61class thread_local_dtor;
62
63class pthread_internal_t {
64 public:
65  class pthread_internal_t* next;
66  class pthread_internal_t* prev;
67
68  pid_t tid;
69
70 private:
71  pid_t cached_pid_;
72
73 public:
74  pid_t invalidate_cached_pid() {
75    pid_t old_value;
76    get_cached_pid(&old_value);
77    set_cached_pid(0);
78    return old_value;
79  }
80
81  void set_cached_pid(pid_t value) {
82    cached_pid_ = value;
83  }
84
85  bool get_cached_pid(pid_t* cached_pid) {
86    *cached_pid = cached_pid_;
87    return (*cached_pid != 0);
88  }
89
90  pthread_attr_t attr;
91
92  _Atomic(ThreadJoinState) join_state;
93
94  __pthread_cleanup_t* cleanup_stack;
95
96  void* (*start_routine)(void*);
97  void* start_routine_arg;
98  void* return_value;
99
100  void* alternate_signal_stack;
101
102  Lock startup_handshake_lock;
103
104  size_t mmap_size;
105
106  thread_local_dtor* thread_local_dtors;
107
108  void* tls[BIONIC_TLS_SLOTS];
109
110  pthread_key_data_t key_data[BIONIC_PTHREAD_KEY_COUNT];
111
112  /*
113   * The dynamic linker implements dlerror(3), which makes it hard for us to implement this
114   * per-thread buffer by simply using malloc(3) and free(3).
115   */
116#define __BIONIC_DLERROR_BUFFER_SIZE 512
117  char dlerror_buffer[__BIONIC_DLERROR_BUFFER_SIZE];
118
119  bionic_tls* bionic_tls;
120};
121
122__LIBC_HIDDEN__ int __init_thread(pthread_internal_t* thread);
123__LIBC_HIDDEN__ bool __init_tls(pthread_internal_t* thread);
124__LIBC_HIDDEN__ void __init_thread_stack_guard(pthread_internal_t* thread);
125__LIBC_HIDDEN__ void __init_alternate_signal_stack(pthread_internal_t*);
126
127__LIBC_HIDDEN__ pthread_t           __pthread_internal_add(pthread_internal_t* thread);
128__LIBC_HIDDEN__ pthread_internal_t* __pthread_internal_find(pthread_t pthread_id);
129__LIBC_HIDDEN__ void                __pthread_internal_remove(pthread_internal_t* thread);
130__LIBC_HIDDEN__ void                __pthread_internal_remove_and_free(pthread_internal_t* thread);
131
132// Make __get_thread() inlined for performance reason. See http://b/19825434.
133static inline __always_inline pthread_internal_t* __get_thread() {
134  void** tls = __get_tls();
135  if (__predict_true(tls)) {
136    return reinterpret_cast<pthread_internal_t*>(tls[TLS_SLOT_THREAD_ID]);
137  }
138
139  // This happens when called during libc initialization before TLS has been initialized.
140  return nullptr;
141}
142
143static inline __always_inline bionic_tls& __get_bionic_tls() {
144  return *__get_thread()->bionic_tls;
145}
146
147__LIBC_HIDDEN__ void pthread_key_clean_all(void);
148
149// Address space is precious on LP32, so use the minimum unit: one page.
150// On LP64, we could use more but there's no obvious advantage to doing
151// so, and the various media processes use RLIMIT_AS as a way to limit
152// the amount of allocation they'll do.
153#define PTHREAD_GUARD_SIZE PAGE_SIZE
154
155// SIGSTKSZ (8KiB) is not big enough.
156// An snprintf to a stack buffer of size PATH_MAX consumes ~7KiB of stack.
157// Also, on 64-bit, logging uses more than 8KiB by itself:
158// https://code.google.com/p/android/issues/detail?id=187064
159#define SIGNAL_STACK_SIZE_WITHOUT_GUARD (16 * 1024)
160
161// Traditionally we gave threads a 1MiB stack. When we started
162// allocating per-thread alternate signal stacks to ease debugging of
163// stack overflows, we subtracted the same amount we were using there
164// from the default thread stack size. This should keep memory usage
165// roughly constant.
166#define PTHREAD_STACK_SIZE_DEFAULT ((1 * 1024 * 1024) - SIGNAL_STACK_SIZE_WITHOUT_GUARD)
167
168// Leave room for a guard page in the internally created signal stacks.
169#define SIGNAL_STACK_SIZE (SIGNAL_STACK_SIZE_WITHOUT_GUARD + PTHREAD_GUARD_SIZE)
170
171// Needed by fork.
172__LIBC_HIDDEN__ extern void __bionic_atfork_run_prepare();
173__LIBC_HIDDEN__ extern void __bionic_atfork_run_child();
174__LIBC_HIDDEN__ extern void __bionic_atfork_run_parent();
175