/usr/include/urcu/tls-compat.h is in liburcu-dev 0.9.1-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 | #ifndef _URCU_TLS_COMPAT_H
#define _URCU_TLS_COMPAT_H
/*
* urcu/tls-compat.h
*
* Userspace RCU library - Thread-Local Storage Compatibility Header
*
* Copyright 2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdlib.h>
#include <urcu/config.h>
#include <urcu/compiler.h>
#include <urcu/arch.h>
#ifdef __cplusplus
extern "C" {
#endif
#ifdef CONFIG_RCU_TLS /* Based on ax_tls.m4 */
/*
* Hint: How to define/declare TLS variables of compound types
* such as array or function pointers?
*
* Answer: Use typedef to assign a type_name to the compound type.
* Example: Define a TLS variable which is an int array with len=4:
*
* typedef int my_int_array_type[4];
* DEFINE_URCU_TLS(my_int_array_type, var_name);
*
* Another example:
* typedef void (*call_rcu_flavor)(struct rcu_head *, XXXX);
* DECLARE_URCU_TLS(call_rcu_flavor, p_call_rcu);
*
* NOTE: URCU_TLS() is NOT async-signal-safe, you can't use it
* inside any function which can be called from signal handler.
*
* But if pthread_getspecific() is async-signal-safe in your
* platform, you can make URCU_TLS() async-signal-safe via:
* ensuring the first call to URCU_TLS() of a given TLS variable of
* all threads is called earliest from a non-signal handler function.
*
* Example: In any thread, the first call of URCU_TLS(rcu_reader)
* is called from rcu_register_thread(), so we can ensure all later
* URCU_TLS(rcu_reader) in any thread is async-signal-safe.
*
* Moreover, URCU_TLS variables should not be touched from signal
* handlers setup with with sigaltstack(2).
*/
# define DECLARE_URCU_TLS(type, name) \
CONFIG_RCU_TLS type name
# define DEFINE_URCU_TLS(type, name) \
CONFIG_RCU_TLS type name
# define URCU_TLS(name) (name)
#else /* #ifndef CONFIG_RCU_TLS */
/*
* The *_1() macros ensure macro parameters are expanded.
*/
# include <pthread.h>
struct urcu_tls {
pthread_key_t key;
pthread_mutex_t init_mutex;
int init_done;
};
# define DECLARE_URCU_TLS_1(type, name) \
type *__tls_access_ ## name(void)
# define DECLARE_URCU_TLS(type, name) \
DECLARE_URCU_TLS_1(type, name)
/*
* Note: we don't free memory at process exit, since it will be dealt
* with by the OS.
*/
# define DEFINE_URCU_TLS_1(type, name) \
type *__tls_access_ ## name(void) \
{ \
static struct urcu_tls __tls_ ## name = { \
.init_mutex = PTHREAD_MUTEX_INITIALIZER,\
.init_done = 0, \
}; \
void *__tls_p; \
if (!__tls_ ## name.init_done) { \
/* Mutex to protect concurrent init */ \
pthread_mutex_lock(&__tls_ ## name.init_mutex); \
if (!__tls_ ## name.init_done) { \
(void) pthread_key_create(&__tls_ ## name.key, \
free); \
cmm_smp_wmb(); /* create key before write init_done */ \
__tls_ ## name.init_done = 1; \
} \
pthread_mutex_unlock(&__tls_ ## name.init_mutex); \
} \
cmm_smp_rmb(); /* read init_done before getting key */ \
__tls_p = pthread_getspecific(__tls_ ## name.key); \
if (caa_unlikely(__tls_p == NULL)) { \
__tls_p = calloc(1, sizeof(type)); \
(void) pthread_setspecific(__tls_ ## name.key, \
__tls_p); \
} \
return __tls_p; \
}
# define DEFINE_URCU_TLS(type, name) \
DEFINE_URCU_TLS_1(type, name)
# define URCU_TLS_1(name) (*__tls_access_ ## name())
# define URCU_TLS(name) URCU_TLS_1(name)
#endif /* #else #ifndef CONFIG_RCU_TLS */
#ifdef __cplusplus
}
#endif
#endif /* _URCU_TLS_COMPAT_H */
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