2 * Utilities and interfaces for managing POSIX threads within FRR.
3 * Copyright (C) 2017 Cumulus Networks, Inc.
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
15 * You should have received a copy of the GNU General Public License along
16 * with this program; see the file COPYING; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22 #ifdef HAVE_PTHREAD_NP_H
23 #include <pthread_np.h>
27 #include "frr_pthread.h"
32 #include "libfrr_trace.h"
34 DEFINE_MTYPE_STATIC(LIB
, FRR_PTHREAD
, "FRR POSIX Thread");
35 DEFINE_MTYPE_STATIC(LIB
, PTHREAD_PRIM
, "POSIX sync primitives");
37 /* default frr_pthread start/stop routine prototypes */
38 static void *fpt_run(void *arg
);
39 static int fpt_halt(struct frr_pthread
*fpt
, void **res
);
42 static void frr_pthread_destroy_nolock(struct frr_pthread
*fpt
);
44 /* default frr_pthread attributes */
45 const struct frr_pthread_attr frr_pthread_attr_default
= {
50 /* list to keep track of all frr_pthreads */
51 static pthread_mutex_t frr_pthread_list_mtx
= PTHREAD_MUTEX_INITIALIZER
;
52 static struct list
*frr_pthread_list
;
54 /* ------------------------------------------------------------------------ */
56 void frr_pthread_init(void)
58 frr_with_mutex(&frr_pthread_list_mtx
) {
59 frr_pthread_list
= list_new();
63 void frr_pthread_finish(void)
65 frr_pthread_stop_all();
67 frr_with_mutex(&frr_pthread_list_mtx
) {
68 struct listnode
*n
, *nn
;
69 struct frr_pthread
*fpt
;
71 for (ALL_LIST_ELEMENTS(frr_pthread_list
, n
, nn
, fpt
)) {
72 listnode_delete(frr_pthread_list
, fpt
);
73 frr_pthread_destroy_nolock(fpt
);
76 list_delete(&frr_pthread_list
);
80 struct frr_pthread
*frr_pthread_new(const struct frr_pthread_attr
*attr
,
81 const char *name
, const char *os_name
)
83 struct frr_pthread
*fpt
= NULL
;
85 attr
= attr
? attr
: &frr_pthread_attr_default
;
87 fpt
= XCALLOC(MTYPE_FRR_PTHREAD
, sizeof(struct frr_pthread
));
88 /* initialize mutex */
89 pthread_mutex_init(&fpt
->mtx
, NULL
);
90 /* create new thread master */
91 fpt
->master
= thread_master_create(name
);
94 name
= (name
? name
: "Anonymous thread");
95 fpt
->name
= XSTRDUP(MTYPE_FRR_PTHREAD
, name
);
97 strlcpy(fpt
->os_name
, os_name
, OS_THREAD_NAMELEN
);
99 strlcpy(fpt
->os_name
, name
, OS_THREAD_NAMELEN
);
100 /* initialize startup synchronization primitives */
101 fpt
->running_cond_mtx
= XCALLOC(
102 MTYPE_PTHREAD_PRIM
, sizeof(pthread_mutex_t
));
103 fpt
->running_cond
= XCALLOC(MTYPE_PTHREAD_PRIM
,
104 sizeof(pthread_cond_t
));
105 pthread_mutex_init(fpt
->running_cond_mtx
, NULL
);
106 pthread_cond_init(fpt
->running_cond
, NULL
);
108 frr_with_mutex(&frr_pthread_list_mtx
) {
109 listnode_add(frr_pthread_list
, fpt
);
115 static void frr_pthread_destroy_nolock(struct frr_pthread
*fpt
)
117 thread_master_free(fpt
->master
);
118 pthread_mutex_destroy(&fpt
->mtx
);
119 pthread_mutex_destroy(fpt
->running_cond_mtx
);
120 pthread_cond_destroy(fpt
->running_cond
);
121 XFREE(MTYPE_FRR_PTHREAD
, fpt
->name
);
122 XFREE(MTYPE_PTHREAD_PRIM
, fpt
->running_cond_mtx
);
123 XFREE(MTYPE_PTHREAD_PRIM
, fpt
->running_cond
);
124 XFREE(MTYPE_FRR_PTHREAD
, fpt
);
127 void frr_pthread_destroy(struct frr_pthread
*fpt
)
129 frr_with_mutex(&frr_pthread_list_mtx
) {
130 listnode_delete(frr_pthread_list
, fpt
);
133 frr_pthread_destroy_nolock(fpt
);
136 int frr_pthread_set_name(struct frr_pthread
*fpt
)
140 #ifdef HAVE_PTHREAD_SETNAME_NP
142 ret
= pthread_setname_np(fpt
->thread
, fpt
->os_name
);
143 # elif defined(__NetBSD__)
144 ret
= pthread_setname_np(fpt
->thread
, fpt
->os_name
, NULL
);
146 #elif defined(HAVE_PTHREAD_SET_NAME_NP)
147 pthread_set_name_np(fpt
->thread
, fpt
->os_name
);
153 static void *frr_pthread_inner(void *arg
)
155 struct frr_pthread
*fpt
= arg
;
157 rcu_thread_start(fpt
->rcu_thread
);
158 return fpt
->attr
.start(fpt
);
161 int frr_pthread_run(struct frr_pthread
*fpt
, const pthread_attr_t
*attr
)
164 sigset_t oldsigs
, blocksigs
;
166 assert(frr_is_after_fork
|| !"trying to start thread before fork()");
168 /* Ensure we never handle signals on a background thread by blocking
169 * everything here (new thread inherits signal mask)
171 sigfillset(&blocksigs
);
172 pthread_sigmask(SIG_BLOCK
, &blocksigs
, &oldsigs
);
174 frrtrace(1, frr_libfrr
, frr_pthread_run
, fpt
->name
);
176 fpt
->rcu_thread
= rcu_thread_prepare();
177 ret
= pthread_create(&fpt
->thread
, attr
, frr_pthread_inner
, fpt
);
179 /* Restore caller's signals */
180 pthread_sigmask(SIG_SETMASK
, &oldsigs
, NULL
);
183 * Per pthread_create(3), the contents of fpt->thread are undefined if
184 * pthread_create() did not succeed. Reset this value to zero.
187 rcu_thread_unprepare(fpt
->rcu_thread
);
188 memset(&fpt
->thread
, 0x00, sizeof(fpt
->thread
));
194 void frr_pthread_wait_running(struct frr_pthread
*fpt
)
196 frr_with_mutex(fpt
->running_cond_mtx
) {
197 while (!fpt
->running
)
198 pthread_cond_wait(fpt
->running_cond
,
199 fpt
->running_cond_mtx
);
203 void frr_pthread_notify_running(struct frr_pthread
*fpt
)
205 frr_with_mutex(fpt
->running_cond_mtx
) {
207 pthread_cond_signal(fpt
->running_cond
);
211 int frr_pthread_stop(struct frr_pthread
*fpt
, void **result
)
213 frrtrace(1, frr_libfrr
, frr_pthread_stop
, fpt
->name
);
215 int ret
= (*fpt
->attr
.stop
)(fpt
, result
);
216 memset(&fpt
->thread
, 0x00, sizeof(fpt
->thread
));
220 void frr_pthread_stop_all(void)
222 frr_with_mutex(&frr_pthread_list_mtx
) {
224 struct frr_pthread
*fpt
;
225 for (ALL_LIST_ELEMENTS_RO(frr_pthread_list
, n
, fpt
)) {
226 if (atomic_load_explicit(&fpt
->running
,
227 memory_order_relaxed
))
228 frr_pthread_stop(fpt
, NULL
);
234 * ----------------------------------------------------------------------------
236 * ----------------------------------------------------------------------------
239 /* dummy task for sleeper pipe */
240 static void fpt_dummy(struct thread
*thread
)
244 /* poison pill task to end event loop */
245 static void fpt_finish(struct thread
*thread
)
247 struct frr_pthread
*fpt
= THREAD_ARG(thread
);
249 atomic_store_explicit(&fpt
->running
, false, memory_order_relaxed
);
252 /* stop function, called from other threads to halt this one */
253 static int fpt_halt(struct frr_pthread
*fpt
, void **res
)
255 thread_add_event(fpt
->master
, &fpt_finish
, fpt
, 0, NULL
);
256 pthread_join(fpt
->thread
, res
);
262 * Entry pthread function & main event loop.
264 * Upon thread start the following actions occur:
266 * - frr_pthread's owner field is set to pthread ID.
267 * - All signals are blocked (except for unblockable signals).
268 * - Pthread's threadmaster is set to never handle pending signals
269 * - Poker pipe for poll() is created and queued as I/O source
270 * - The frr_pthread->running_cond condition variable is signalled to indicate
271 * that the previous actions have completed. It is not safe to assume any of
272 * the above have occurred before receiving this signal.
274 * After initialization is completed, the event loop begins running. Each tick,
275 * the following actions are performed before running the usual event system
278 * - Verify that the running boolean is set
279 * - Verify that there are no pending cancellation requests
280 * - Verify that there are tasks scheduled
282 * So long as the conditions are met, the event loop tick is run and the
283 * returned task is executed.
285 * If any of these conditions are not met, the event loop exits, closes the
286 * pipes and dies without running any cleanup functions.
288 static void *fpt_run(void *arg
)
290 struct frr_pthread
*fpt
= arg
;
291 fpt
->master
->owner
= pthread_self();
293 zlog_tls_buffer_init();
297 thread_add_read(fpt
->master
, &fpt_dummy
, NULL
, sleeper
[0], NULL
);
299 fpt
->master
->handle_signals
= false;
301 frr_pthread_set_name(fpt
);
303 frr_pthread_notify_running(fpt
);
306 while (atomic_load_explicit(&fpt
->running
, memory_order_relaxed
)) {
307 pthread_testcancel();
308 if (thread_fetch(fpt
->master
, &task
)) {
316 zlog_tls_buffer_fini();