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98f14af8 | 1 | /* |
a45dc974 | 2 | * Utilities and interfaces for managing POSIX threads within FRR. |
d8a8a8de | 3 | * Copyright (C) 2017 Cumulus Networks, Inc. |
896014f4 DL |
4 | * |
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. | |
9 | * | |
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. | |
14 | * | |
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 | |
98f14af8 QY |
18 | */ |
19 | ||
20 | #include <zebra.h> | |
21 | #include <pthread.h> | |
324be174 DL |
22 | #ifdef HAVE_PTHREAD_NP_H |
23 | #include <pthread_np.h> | |
24 | #endif | |
b2140cb7 | 25 | #include <sched.h> |
98f14af8 QY |
26 | |
27 | #include "frr_pthread.h" | |
28 | #include "memory.h" | |
1ac267a2 | 29 | #include "linklist.h" |
98f14af8 | 30 | |
eaf58ba9 DL |
31 | DEFINE_MTYPE_STATIC(LIB, FRR_PTHREAD, "FRR POSIX Thread") |
32 | DEFINE_MTYPE_STATIC(LIB, PTHREAD_PRIM, "POSIX sync primitives") | |
98f14af8 | 33 | |
a45dc974 QY |
34 | /* default frr_pthread start/stop routine prototypes */ |
35 | static void *fpt_run(void *arg); | |
36 | static int fpt_halt(struct frr_pthread *fpt, void **res); | |
98f14af8 | 37 | |
9af949cc QY |
38 | /* misc sigs */ |
39 | static void frr_pthread_destroy_nolock(struct frr_pthread *fpt); | |
40 | ||
a45dc974 | 41 | /* default frr_pthread attributes */ |
2b64873d | 42 | const struct frr_pthread_attr frr_pthread_attr_default = { |
a45dc974 QY |
43 | .start = fpt_run, |
44 | .stop = fpt_halt, | |
a45dc974 QY |
45 | }; |
46 | ||
1ac267a2 DL |
47 | /* list to keep track of all frr_pthreads */ |
48 | static pthread_mutex_t frr_pthread_list_mtx = PTHREAD_MUTEX_INITIALIZER; | |
49 | static struct list *frr_pthread_list; | |
a45dc974 | 50 | |
98f14af8 QY |
51 | /* ------------------------------------------------------------------------ */ |
52 | ||
4d762f26 | 53 | void frr_pthread_init(void) |
98f14af8 | 54 | { |
00dffa8c | 55 | frr_with_mutex(&frr_pthread_list_mtx) { |
1ac267a2 | 56 | frr_pthread_list = list_new(); |
d62a17ae | 57 | } |
98f14af8 QY |
58 | } |
59 | ||
4d762f26 | 60 | void frr_pthread_finish(void) |
98f14af8 | 61 | { |
54baf432 QY |
62 | frr_pthread_stop_all(); |
63 | ||
00dffa8c | 64 | frr_with_mutex(&frr_pthread_list_mtx) { |
9af949cc QY |
65 | struct listnode *n, *nn; |
66 | struct frr_pthread *fpt; | |
67 | ||
68 | for (ALL_LIST_ELEMENTS(frr_pthread_list, n, nn, fpt)) { | |
69 | listnode_delete(frr_pthread_list, fpt); | |
70 | frr_pthread_destroy_nolock(fpt); | |
71 | } | |
72 | ||
6a154c88 | 73 | list_delete(&frr_pthread_list); |
d62a17ae | 74 | } |
98f14af8 QY |
75 | } |
76 | ||
2b64873d | 77 | struct frr_pthread *frr_pthread_new(const struct frr_pthread_attr *attr, |
57019528 | 78 | const char *name, const char *os_name) |
98f14af8 | 79 | { |
d62a17ae | 80 | struct frr_pthread *fpt = NULL; |
81 | ||
a45dc974 QY |
82 | attr = attr ? attr : &frr_pthread_attr_default; |
83 | ||
1ac267a2 DL |
84 | fpt = XCALLOC(MTYPE_FRR_PTHREAD, sizeof(struct frr_pthread)); |
85 | /* initialize mutex */ | |
86 | pthread_mutex_init(&fpt->mtx, NULL); | |
87 | /* create new thread master */ | |
88 | fpt->master = thread_master_create(name); | |
89 | /* set attributes */ | |
90 | fpt->attr = *attr; | |
91 | name = (name ? name : "Anonymous thread"); | |
92 | fpt->name = XSTRDUP(MTYPE_FRR_PTHREAD, name); | |
93 | if (os_name) | |
e77cc2a9 | 94 | strlcpy(fpt->os_name, os_name, OS_THREAD_NAMELEN); |
b8dccd94 | 95 | else |
e77cc2a9 | 96 | strlcpy(fpt->os_name, name, OS_THREAD_NAMELEN); |
1ac267a2 DL |
97 | /* initialize startup synchronization primitives */ |
98 | fpt->running_cond_mtx = XCALLOC( | |
99 | MTYPE_PTHREAD_PRIM, sizeof(pthread_mutex_t)); | |
100 | fpt->running_cond = XCALLOC(MTYPE_PTHREAD_PRIM, | |
101 | sizeof(pthread_cond_t)); | |
102 | pthread_mutex_init(fpt->running_cond_mtx, NULL); | |
103 | pthread_cond_init(fpt->running_cond, NULL); | |
104 | ||
00dffa8c | 105 | frr_with_mutex(&frr_pthread_list_mtx) { |
1ac267a2 | 106 | listnode_add(frr_pthread_list, fpt); |
d62a17ae | 107 | } |
d62a17ae | 108 | |
109 | return fpt; | |
98f14af8 QY |
110 | } |
111 | ||
9af949cc | 112 | static void frr_pthread_destroy_nolock(struct frr_pthread *fpt) |
98f14af8 | 113 | { |
54baf432 | 114 | thread_master_free(fpt->master); |
d8a8a8de | 115 | pthread_mutex_destroy(&fpt->mtx); |
a45dc974 QY |
116 | pthread_mutex_destroy(fpt->running_cond_mtx); |
117 | pthread_cond_destroy(fpt->running_cond); | |
0a22ddfb | 118 | XFREE(MTYPE_FRR_PTHREAD, fpt->name); |
a45dc974 QY |
119 | XFREE(MTYPE_PTHREAD_PRIM, fpt->running_cond_mtx); |
120 | XFREE(MTYPE_PTHREAD_PRIM, fpt->running_cond); | |
d62a17ae | 121 | XFREE(MTYPE_FRR_PTHREAD, fpt); |
98f14af8 QY |
122 | } |
123 | ||
9af949cc QY |
124 | void frr_pthread_destroy(struct frr_pthread *fpt) |
125 | { | |
126 | frr_with_mutex(&frr_pthread_list_mtx) { | |
127 | listnode_delete(frr_pthread_list, fpt); | |
128 | } | |
129 | ||
130 | frr_pthread_destroy_nolock(fpt); | |
131 | } | |
132 | ||
c80bedb8 | 133 | int frr_pthread_set_name(struct frr_pthread *fpt) |
d8a8a8de | 134 | { |
57019528 CS |
135 | int ret = 0; |
136 | ||
e9d938b8 DL |
137 | #ifdef HAVE_PTHREAD_SETNAME_NP |
138 | # ifdef GNU_LINUX | |
c80bedb8 | 139 | ret = pthread_setname_np(fpt->thread, fpt->os_name); |
a64c953a | 140 | # elif defined(__NetBSD__) |
c80bedb8 | 141 | ret = pthread_setname_np(fpt->thread, fpt->os_name, NULL); |
e9d938b8 DL |
142 | # endif |
143 | #elif defined(HAVE_PTHREAD_SET_NAME_NP) | |
c80bedb8 | 144 | pthread_set_name_np(fpt->thread, fpt->os_name); |
57019528 | 145 | #endif |
57019528 CS |
146 | |
147 | return ret; | |
d8a8a8de QY |
148 | } |
149 | ||
3e41733f DL |
150 | static void *frr_pthread_inner(void *arg) |
151 | { | |
152 | struct frr_pthread *fpt = arg; | |
153 | ||
154 | rcu_thread_start(fpt->rcu_thread); | |
155 | return fpt->attr.start(fpt); | |
156 | } | |
157 | ||
a45dc974 | 158 | int frr_pthread_run(struct frr_pthread *fpt, const pthread_attr_t *attr) |
98f14af8 | 159 | { |
d62a17ae | 160 | int ret; |
98f14af8 | 161 | |
3e41733f DL |
162 | fpt->rcu_thread = rcu_thread_prepare(); |
163 | ret = pthread_create(&fpt->thread, attr, frr_pthread_inner, fpt); | |
98f14af8 | 164 | |
a45dc974 QY |
165 | /* |
166 | * Per pthread_create(3), the contents of fpt->thread are undefined if | |
167 | * pthread_create() did not succeed. Reset this value to zero. | |
168 | */ | |
3e41733f DL |
169 | if (ret < 0) { |
170 | rcu_thread_unprepare(fpt->rcu_thread); | |
d62a17ae | 171 | memset(&fpt->thread, 0x00, sizeof(fpt->thread)); |
3e41733f | 172 | } |
98f14af8 | 173 | |
d62a17ae | 174 | return ret; |
98f14af8 QY |
175 | } |
176 | ||
a45dc974 | 177 | void frr_pthread_wait_running(struct frr_pthread *fpt) |
98f14af8 | 178 | { |
00dffa8c | 179 | frr_with_mutex(fpt->running_cond_mtx) { |
a45dc974 QY |
180 | while (!fpt->running) |
181 | pthread_cond_wait(fpt->running_cond, | |
182 | fpt->running_cond_mtx); | |
183 | } | |
98f14af8 QY |
184 | } |
185 | ||
a45dc974 | 186 | void frr_pthread_notify_running(struct frr_pthread *fpt) |
98f14af8 | 187 | { |
00dffa8c | 188 | frr_with_mutex(fpt->running_cond_mtx) { |
a45dc974 QY |
189 | fpt->running = true; |
190 | pthread_cond_signal(fpt->running_cond); | |
191 | } | |
98f14af8 QY |
192 | } |
193 | ||
a45dc974 QY |
194 | int frr_pthread_stop(struct frr_pthread *fpt, void **result) |
195 | { | |
196 | int ret = (*fpt->attr.stop)(fpt, result); | |
197 | memset(&fpt->thread, 0x00, sizeof(fpt->thread)); | |
198 | return ret; | |
199 | } | |
200 | ||
4d762f26 | 201 | void frr_pthread_stop_all(void) |
98f14af8 | 202 | { |
00dffa8c | 203 | frr_with_mutex(&frr_pthread_list_mtx) { |
1ac267a2 DL |
204 | struct listnode *n; |
205 | struct frr_pthread *fpt; | |
54baf432 QY |
206 | for (ALL_LIST_ELEMENTS_RO(frr_pthread_list, n, fpt)) { |
207 | if (atomic_load_explicit(&fpt->running, | |
208 | memory_order_relaxed)) | |
209 | frr_pthread_stop(fpt, NULL); | |
210 | } | |
d62a17ae | 211 | } |
98f14af8 | 212 | } |
b2140cb7 | 213 | |
a45dc974 QY |
214 | /* |
215 | * ---------------------------------------------------------------------------- | |
216 | * Default Event Loop | |
217 | * ---------------------------------------------------------------------------- | |
218 | */ | |
219 | ||
220 | /* dummy task for sleeper pipe */ | |
221 | static int fpt_dummy(struct thread *thread) | |
222 | { | |
223 | return 0; | |
224 | } | |
225 | ||
226 | /* poison pill task to end event loop */ | |
227 | static int fpt_finish(struct thread *thread) | |
228 | { | |
229 | struct frr_pthread *fpt = THREAD_ARG(thread); | |
985e36a6 | 230 | |
a45dc974 QY |
231 | atomic_store_explicit(&fpt->running, false, memory_order_relaxed); |
232 | return 0; | |
233 | } | |
234 | ||
235 | /* stop function, called from other threads to halt this one */ | |
236 | static int fpt_halt(struct frr_pthread *fpt, void **res) | |
237 | { | |
238 | thread_add_event(fpt->master, &fpt_finish, fpt, 0, NULL); | |
239 | pthread_join(fpt->thread, res); | |
a45dc974 QY |
240 | |
241 | return 0; | |
242 | } | |
243 | ||
a6275055 QY |
244 | /* |
245 | * Entry pthread function & main event loop. | |
246 | * | |
247 | * Upon thread start the following actions occur: | |
248 | * | |
249 | * - frr_pthread's owner field is set to pthread ID. | |
250 | * - All signals are blocked (except for unblockable signals). | |
251 | * - Pthread's threadmaster is set to never handle pending signals | |
252 | * - Poker pipe for poll() is created and queued as I/O source | |
253 | * - The frr_pthread->running_cond condition variable is signalled to indicate | |
254 | * that the previous actions have completed. It is not safe to assume any of | |
255 | * the above have occurred before receiving this signal. | |
256 | * | |
257 | * After initialization is completed, the event loop begins running. Each tick, | |
258 | * the following actions are performed before running the usual event system | |
259 | * tick function: | |
260 | * | |
261 | * - Verify that the running boolean is set | |
262 | * - Verify that there are no pending cancellation requests | |
263 | * - Verify that there are tasks scheduled | |
264 | * | |
265 | * So long as the conditions are met, the event loop tick is run and the | |
266 | * returned task is executed. | |
267 | * | |
268 | * If any of these conditions are not met, the event loop exits, closes the | |
269 | * pipes and dies without running any cleanup functions. | |
270 | */ | |
a45dc974 QY |
271 | static void *fpt_run(void *arg) |
272 | { | |
273 | struct frr_pthread *fpt = arg; | |
274 | fpt->master->owner = pthread_self(); | |
275 | ||
276 | int sleeper[2]; | |
277 | pipe(sleeper); | |
278 | thread_add_read(fpt->master, &fpt_dummy, NULL, sleeper[0], NULL); | |
279 | ||
280 | fpt->master->handle_signals = false; | |
281 | ||
c80bedb8 | 282 | frr_pthread_set_name(fpt); |
57019528 | 283 | |
a45dc974 QY |
284 | frr_pthread_notify_running(fpt); |
285 | ||
286 | struct thread task; | |
287 | while (atomic_load_explicit(&fpt->running, memory_order_relaxed)) { | |
a6275055 | 288 | pthread_testcancel(); |
a45dc974 QY |
289 | if (thread_fetch(fpt->master, &task)) { |
290 | thread_call(&task); | |
291 | } | |
292 | } | |
293 | ||
294 | close(sleeper[1]); | |
295 | close(sleeper[0]); | |
296 | ||
297 | return NULL; | |
298 | } |