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
48 class 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
54 enum ThreadJoinState {
55 THREAD_NOT_JOINED,
56 THREAD_EXITED_NOT_JOINED,
57 THREAD_JOINED,
58 THREAD_DETACHED
59 };
60
61 class thread_local_dtor;
62
63 class 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:
invalidate_cached_pid()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
set_cached_pid(pid_t value)81 void set_cached_pid(pid_t value) {
82 cached_pid_ = value;
83 }
84
get_cached_pid(pid_t * cached_pid)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.
__get_thread()133 static 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
__get_bionic_tls()143 static 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