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acddc0ed | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
98f14af8 | 2 | /* |
a45dc974 | 3 | * Utilities and interfaces for managing POSIX threads within FRR. |
d8a8a8de | 4 | * Copyright (C) 2017 Cumulus Networks, Inc. |
98f14af8 QY |
5 | */ |
6 | ||
7 | #include <zebra.h> | |
8 | #include <pthread.h> | |
324be174 DL |
9 | #ifdef HAVE_PTHREAD_NP_H |
10 | #include <pthread_np.h> | |
11 | #endif | |
b2140cb7 | 12 | #include <sched.h> |
98f14af8 QY |
13 | |
14 | #include "frr_pthread.h" | |
15 | #include "memory.h" | |
1ac267a2 | 16 | #include "linklist.h" |
0bdeb5e5 | 17 | #include "zlog.h" |
38554d3a | 18 | #include "libfrr.h" |
912d45a1 | 19 | #include "libfrr_trace.h" |
98f14af8 | 20 | |
bf8d3d6a DL |
21 | DEFINE_MTYPE_STATIC(LIB, FRR_PTHREAD, "FRR POSIX Thread"); |
22 | DEFINE_MTYPE_STATIC(LIB, PTHREAD_PRIM, "POSIX sync primitives"); | |
98f14af8 | 23 | |
a45dc974 QY |
24 | /* default frr_pthread start/stop routine prototypes */ |
25 | static void *fpt_run(void *arg); | |
26 | static int fpt_halt(struct frr_pthread *fpt, void **res); | |
98f14af8 | 27 | |
9af949cc QY |
28 | /* misc sigs */ |
29 | static void frr_pthread_destroy_nolock(struct frr_pthread *fpt); | |
30 | ||
a45dc974 | 31 | /* default frr_pthread attributes */ |
2b64873d | 32 | const struct frr_pthread_attr frr_pthread_attr_default = { |
a45dc974 QY |
33 | .start = fpt_run, |
34 | .stop = fpt_halt, | |
a45dc974 QY |
35 | }; |
36 | ||
1ac267a2 DL |
37 | /* list to keep track of all frr_pthreads */ |
38 | static pthread_mutex_t frr_pthread_list_mtx = PTHREAD_MUTEX_INITIALIZER; | |
39 | static struct list *frr_pthread_list; | |
a45dc974 | 40 | |
98f14af8 QY |
41 | /* ------------------------------------------------------------------------ */ |
42 | ||
4d762f26 | 43 | void frr_pthread_init(void) |
98f14af8 | 44 | { |
cb1991af | 45 | frr_with_mutex (&frr_pthread_list_mtx) { |
1ac267a2 | 46 | frr_pthread_list = list_new(); |
d62a17ae | 47 | } |
98f14af8 QY |
48 | } |
49 | ||
4d762f26 | 50 | void frr_pthread_finish(void) |
98f14af8 | 51 | { |
54baf432 QY |
52 | frr_pthread_stop_all(); |
53 | ||
cb1991af | 54 | frr_with_mutex (&frr_pthread_list_mtx) { |
9af949cc QY |
55 | struct listnode *n, *nn; |
56 | struct frr_pthread *fpt; | |
57 | ||
58 | for (ALL_LIST_ELEMENTS(frr_pthread_list, n, nn, fpt)) { | |
59 | listnode_delete(frr_pthread_list, fpt); | |
60 | frr_pthread_destroy_nolock(fpt); | |
61 | } | |
62 | ||
6a154c88 | 63 | list_delete(&frr_pthread_list); |
d62a17ae | 64 | } |
98f14af8 QY |
65 | } |
66 | ||
2b64873d | 67 | struct frr_pthread *frr_pthread_new(const struct frr_pthread_attr *attr, |
57019528 | 68 | const char *name, const char *os_name) |
98f14af8 | 69 | { |
d62a17ae | 70 | struct frr_pthread *fpt = NULL; |
71 | ||
a45dc974 QY |
72 | attr = attr ? attr : &frr_pthread_attr_default; |
73 | ||
1ac267a2 DL |
74 | fpt = XCALLOC(MTYPE_FRR_PTHREAD, sizeof(struct frr_pthread)); |
75 | /* initialize mutex */ | |
76 | pthread_mutex_init(&fpt->mtx, NULL); | |
77 | /* create new thread master */ | |
ce50d11c | 78 | fpt->master = event_master_create(name); |
1ac267a2 DL |
79 | /* set attributes */ |
80 | fpt->attr = *attr; | |
81 | name = (name ? name : "Anonymous thread"); | |
82 | fpt->name = XSTRDUP(MTYPE_FRR_PTHREAD, name); | |
83 | if (os_name) | |
e77cc2a9 | 84 | strlcpy(fpt->os_name, os_name, OS_THREAD_NAMELEN); |
b8dccd94 | 85 | else |
e77cc2a9 | 86 | strlcpy(fpt->os_name, name, OS_THREAD_NAMELEN); |
1ac267a2 DL |
87 | /* initialize startup synchronization primitives */ |
88 | fpt->running_cond_mtx = XCALLOC( | |
89 | MTYPE_PTHREAD_PRIM, sizeof(pthread_mutex_t)); | |
90 | fpt->running_cond = XCALLOC(MTYPE_PTHREAD_PRIM, | |
91 | sizeof(pthread_cond_t)); | |
92 | pthread_mutex_init(fpt->running_cond_mtx, NULL); | |
93 | pthread_cond_init(fpt->running_cond, NULL); | |
94 | ||
cb1991af | 95 | frr_with_mutex (&frr_pthread_list_mtx) { |
1ac267a2 | 96 | listnode_add(frr_pthread_list, fpt); |
d62a17ae | 97 | } |
d62a17ae | 98 | |
99 | return fpt; | |
98f14af8 QY |
100 | } |
101 | ||
9af949cc | 102 | static void frr_pthread_destroy_nolock(struct frr_pthread *fpt) |
98f14af8 | 103 | { |
ce50d11c | 104 | event_master_free(fpt->master); |
d8a8a8de | 105 | pthread_mutex_destroy(&fpt->mtx); |
a45dc974 QY |
106 | pthread_mutex_destroy(fpt->running_cond_mtx); |
107 | pthread_cond_destroy(fpt->running_cond); | |
0a22ddfb | 108 | XFREE(MTYPE_FRR_PTHREAD, fpt->name); |
a45dc974 QY |
109 | XFREE(MTYPE_PTHREAD_PRIM, fpt->running_cond_mtx); |
110 | XFREE(MTYPE_PTHREAD_PRIM, fpt->running_cond); | |
d62a17ae | 111 | XFREE(MTYPE_FRR_PTHREAD, fpt); |
98f14af8 QY |
112 | } |
113 | ||
9af949cc QY |
114 | void frr_pthread_destroy(struct frr_pthread *fpt) |
115 | { | |
cb1991af | 116 | frr_with_mutex (&frr_pthread_list_mtx) { |
9af949cc QY |
117 | listnode_delete(frr_pthread_list, fpt); |
118 | } | |
119 | ||
120 | frr_pthread_destroy_nolock(fpt); | |
121 | } | |
122 | ||
c80bedb8 | 123 | int frr_pthread_set_name(struct frr_pthread *fpt) |
d8a8a8de | 124 | { |
57019528 CS |
125 | int ret = 0; |
126 | ||
e9d938b8 DL |
127 | #ifdef HAVE_PTHREAD_SETNAME_NP |
128 | # ifdef GNU_LINUX | |
c80bedb8 | 129 | ret = pthread_setname_np(fpt->thread, fpt->os_name); |
a64c953a | 130 | # elif defined(__NetBSD__) |
c80bedb8 | 131 | ret = pthread_setname_np(fpt->thread, fpt->os_name, NULL); |
e9d938b8 DL |
132 | # endif |
133 | #elif defined(HAVE_PTHREAD_SET_NAME_NP) | |
c80bedb8 | 134 | pthread_set_name_np(fpt->thread, fpt->os_name); |
57019528 | 135 | #endif |
57019528 CS |
136 | |
137 | return ret; | |
d8a8a8de QY |
138 | } |
139 | ||
3e41733f DL |
140 | static void *frr_pthread_inner(void *arg) |
141 | { | |
142 | struct frr_pthread *fpt = arg; | |
143 | ||
144 | rcu_thread_start(fpt->rcu_thread); | |
145 | return fpt->attr.start(fpt); | |
146 | } | |
147 | ||
a45dc974 | 148 | int frr_pthread_run(struct frr_pthread *fpt, const pthread_attr_t *attr) |
98f14af8 | 149 | { |
d62a17ae | 150 | int ret; |
f4635e33 MS |
151 | sigset_t oldsigs, blocksigs; |
152 | ||
38554d3a DL |
153 | assert(frr_is_after_fork || !"trying to start thread before fork()"); |
154 | ||
f4635e33 MS |
155 | /* Ensure we never handle signals on a background thread by blocking |
156 | * everything here (new thread inherits signal mask) | |
157 | */ | |
158 | sigfillset(&blocksigs); | |
159 | pthread_sigmask(SIG_BLOCK, &blocksigs, &oldsigs); | |
98f14af8 | 160 | |
c7bb4f00 | 161 | frrtrace(1, frr_libfrr, frr_pthread_run, fpt->name); |
87879a5e | 162 | |
3e41733f DL |
163 | fpt->rcu_thread = rcu_thread_prepare(); |
164 | ret = pthread_create(&fpt->thread, attr, frr_pthread_inner, fpt); | |
98f14af8 | 165 | |
f4635e33 MS |
166 | /* Restore caller's signals */ |
167 | pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); | |
168 | ||
a45dc974 QY |
169 | /* |
170 | * Per pthread_create(3), the contents of fpt->thread are undefined if | |
171 | * pthread_create() did not succeed. Reset this value to zero. | |
172 | */ | |
3e41733f DL |
173 | if (ret < 0) { |
174 | rcu_thread_unprepare(fpt->rcu_thread); | |
d62a17ae | 175 | memset(&fpt->thread, 0x00, sizeof(fpt->thread)); |
3e41733f | 176 | } |
98f14af8 | 177 | |
d62a17ae | 178 | return ret; |
98f14af8 QY |
179 | } |
180 | ||
a45dc974 | 181 | void frr_pthread_wait_running(struct frr_pthread *fpt) |
98f14af8 | 182 | { |
cb1991af | 183 | frr_with_mutex (fpt->running_cond_mtx) { |
a45dc974 QY |
184 | while (!fpt->running) |
185 | pthread_cond_wait(fpt->running_cond, | |
186 | fpt->running_cond_mtx); | |
187 | } | |
98f14af8 QY |
188 | } |
189 | ||
a45dc974 | 190 | void frr_pthread_notify_running(struct frr_pthread *fpt) |
98f14af8 | 191 | { |
cb1991af | 192 | frr_with_mutex (fpt->running_cond_mtx) { |
a45dc974 QY |
193 | fpt->running = true; |
194 | pthread_cond_signal(fpt->running_cond); | |
195 | } | |
98f14af8 QY |
196 | } |
197 | ||
a45dc974 QY |
198 | int frr_pthread_stop(struct frr_pthread *fpt, void **result) |
199 | { | |
c7bb4f00 | 200 | frrtrace(1, frr_libfrr, frr_pthread_stop, fpt->name); |
87879a5e | 201 | |
a45dc974 QY |
202 | int ret = (*fpt->attr.stop)(fpt, result); |
203 | memset(&fpt->thread, 0x00, sizeof(fpt->thread)); | |
204 | return ret; | |
205 | } | |
206 | ||
4d762f26 | 207 | void frr_pthread_stop_all(void) |
98f14af8 | 208 | { |
cb1991af | 209 | frr_with_mutex (&frr_pthread_list_mtx) { |
1ac267a2 DL |
210 | struct listnode *n; |
211 | struct frr_pthread *fpt; | |
54baf432 QY |
212 | for (ALL_LIST_ELEMENTS_RO(frr_pthread_list, n, fpt)) { |
213 | if (atomic_load_explicit(&fpt->running, | |
214 | memory_order_relaxed)) | |
215 | frr_pthread_stop(fpt, NULL); | |
216 | } | |
d62a17ae | 217 | } |
98f14af8 | 218 | } |
b2140cb7 | 219 | |
a45dc974 QY |
220 | /* |
221 | * ---------------------------------------------------------------------------- | |
222 | * Default Event Loop | |
223 | * ---------------------------------------------------------------------------- | |
224 | */ | |
225 | ||
226 | /* dummy task for sleeper pipe */ | |
e6685141 | 227 | static void fpt_dummy(struct event *thread) |
a45dc974 | 228 | { |
a45dc974 QY |
229 | } |
230 | ||
231 | /* poison pill task to end event loop */ | |
e6685141 | 232 | static void fpt_finish(struct event *thread) |
a45dc974 | 233 | { |
e16d030c | 234 | struct frr_pthread *fpt = EVENT_ARG(thread); |
985e36a6 | 235 | |
a45dc974 | 236 | atomic_store_explicit(&fpt->running, false, memory_order_relaxed); |
a45dc974 QY |
237 | } |
238 | ||
239 | /* stop function, called from other threads to halt this one */ | |
240 | static int fpt_halt(struct frr_pthread *fpt, void **res) | |
241 | { | |
907a2395 | 242 | event_add_event(fpt->master, &fpt_finish, fpt, 0, NULL); |
a45dc974 | 243 | pthread_join(fpt->thread, res); |
a45dc974 QY |
244 | |
245 | return 0; | |
246 | } | |
247 | ||
a6275055 QY |
248 | /* |
249 | * Entry pthread function & main event loop. | |
250 | * | |
251 | * Upon thread start the following actions occur: | |
252 | * | |
253 | * - frr_pthread's owner field is set to pthread ID. | |
254 | * - All signals are blocked (except for unblockable signals). | |
255 | * - Pthread's threadmaster is set to never handle pending signals | |
256 | * - Poker pipe for poll() is created and queued as I/O source | |
257 | * - The frr_pthread->running_cond condition variable is signalled to indicate | |
258 | * that the previous actions have completed. It is not safe to assume any of | |
259 | * the above have occurred before receiving this signal. | |
260 | * | |
261 | * After initialization is completed, the event loop begins running. Each tick, | |
262 | * the following actions are performed before running the usual event system | |
263 | * tick function: | |
264 | * | |
265 | * - Verify that the running boolean is set | |
266 | * - Verify that there are no pending cancellation requests | |
267 | * - Verify that there are tasks scheduled | |
268 | * | |
269 | * So long as the conditions are met, the event loop tick is run and the | |
270 | * returned task is executed. | |
271 | * | |
272 | * If any of these conditions are not met, the event loop exits, closes the | |
273 | * pipes and dies without running any cleanup functions. | |
274 | */ | |
a45dc974 QY |
275 | static void *fpt_run(void *arg) |
276 | { | |
277 | struct frr_pthread *fpt = arg; | |
278 | fpt->master->owner = pthread_self(); | |
279 | ||
0bdeb5e5 DL |
280 | zlog_tls_buffer_init(); |
281 | ||
a45dc974 QY |
282 | int sleeper[2]; |
283 | pipe(sleeper); | |
907a2395 | 284 | event_add_read(fpt->master, &fpt_dummy, NULL, sleeper[0], NULL); |
a45dc974 QY |
285 | |
286 | fpt->master->handle_signals = false; | |
287 | ||
c80bedb8 | 288 | frr_pthread_set_name(fpt); |
57019528 | 289 | |
a45dc974 QY |
290 | frr_pthread_notify_running(fpt); |
291 | ||
e6685141 | 292 | struct event task; |
a45dc974 | 293 | while (atomic_load_explicit(&fpt->running, memory_order_relaxed)) { |
a6275055 | 294 | pthread_testcancel(); |
de2754be DS |
295 | if (event_fetch(fpt->master, &task)) { |
296 | event_call(&task); | |
a45dc974 QY |
297 | } |
298 | } | |
299 | ||
300 | close(sleeper[1]); | |
301 | close(sleeper[0]); | |
302 | ||
0bdeb5e5 DL |
303 | zlog_tls_buffer_fini(); |
304 | ||
a45dc974 QY |
305 | return NULL; |
306 | } |