Commit | Line | Data |
---|---|---|
b878f05a | 1 | /* |
ab5be9fa | 2 | * Copyright (C) 2018 Jérémie Galarneau <jeremie.galarneau@efficios.com> |
b878f05a | 3 | * |
ab5be9fa | 4 | * SPDX-License-Identifier: GPL-2.0-only |
b878f05a | 5 | * |
b878f05a JG |
6 | */ |
7 | ||
8 | #include "thread.h" | |
9 | #include <urcu/list.h> | |
10 | #include <urcu/ref.h> | |
11 | #include <pthread.h> | |
12 | #include <common/macros.h> | |
13 | #include <common/error.h> | |
14 | #include <common/defaults.h> | |
15 | ||
16 | static struct thread_list { | |
17 | struct cds_list_head head; | |
18 | pthread_mutex_t lock; | |
19 | } thread_list = { | |
20 | .head = CDS_LIST_HEAD_INIT(thread_list.head), | |
21 | .lock = PTHREAD_MUTEX_INITIALIZER, | |
22 | }; | |
23 | ||
24 | struct lttng_thread { | |
25 | struct urcu_ref ref; | |
26 | struct cds_list_head node; | |
27 | pthread_t thread; | |
28 | const char *name; | |
29 | /* Main thread function */ | |
30 | lttng_thread_entry_point entry; | |
31 | /* | |
32 | * Thread-specific shutdown method. Allows threads to implement their | |
33 | * own shutdown mechanism as some of them use a structured message | |
34 | * passed through a command queue and some rely on a dedicated "quit" | |
35 | * pipe. | |
36 | */ | |
37 | lttng_thread_shutdown_cb shutdown; | |
38 | lttng_thread_cleanup_cb cleanup; | |
39 | /* Thread implementation-specific data. */ | |
40 | void *data; | |
41 | }; | |
42 | ||
43 | static | |
44 | void lttng_thread_destroy(struct lttng_thread *thread) | |
45 | { | |
46 | if (thread->cleanup) { | |
47 | thread->cleanup(thread->data); | |
48 | } | |
49 | free(thread); | |
50 | } | |
51 | ||
52 | static | |
53 | void lttng_thread_release(struct urcu_ref *ref) | |
54 | { | |
55 | lttng_thread_destroy(container_of(ref, struct lttng_thread, ref)); | |
56 | } | |
57 | ||
58 | static | |
59 | void *launch_thread(void *data) | |
60 | { | |
61 | void *ret; | |
62 | struct lttng_thread *thread = (struct lttng_thread *) data; | |
63 | ||
f5fb86c1 JG |
64 | logger_set_thread_name(thread->name, true); |
65 | DBG("Entering thread entry point"); | |
b878f05a | 66 | ret = thread->entry(thread->data); |
f5fb86c1 | 67 | DBG("Thread entry point has returned"); |
b878f05a JG |
68 | return ret; |
69 | } | |
70 | ||
71 | struct lttng_thread *lttng_thread_create(const char *name, | |
72 | lttng_thread_entry_point entry, | |
73 | lttng_thread_shutdown_cb shutdown, | |
74 | lttng_thread_cleanup_cb cleanup, | |
75 | void *thread_data) | |
76 | { | |
77 | int ret; | |
78 | struct lttng_thread *thread; | |
79 | ||
80 | thread = zmalloc(sizeof(*thread)); | |
81 | if (!thread) { | |
21fa020e | 82 | goto error_alloc; |
b878f05a JG |
83 | } |
84 | ||
85 | urcu_ref_init(&thread->ref); | |
86 | CDS_INIT_LIST_HEAD(&thread->node); | |
87 | /* | |
88 | * Thread names are assumed to be statically allocated strings. | |
89 | * It is unnecessary to copy this attribute. | |
90 | */ | |
91 | thread->name = name; | |
92 | thread->entry = entry; | |
93 | thread->shutdown = shutdown; | |
94 | thread->cleanup = cleanup; | |
95 | thread->data = thread_data; | |
96 | ||
97 | pthread_mutex_lock(&thread_list.lock); | |
98 | /* | |
99 | * Add the thread at the head of the list to shutdown threads in the | |
100 | * opposite order of their creation. A reference is taken for the | |
101 | * thread list which will be released on shutdown of the thread. | |
102 | */ | |
103 | cds_list_add(&thread->node, &thread_list.head); | |
104 | (void) lttng_thread_get(thread); | |
105 | ||
106 | ret = pthread_create(&thread->thread, default_pthread_attr(), | |
107 | launch_thread, thread); | |
108 | if (ret) { | |
109 | PERROR("Failed to create \"%s\" thread", thread->name); | |
110 | goto error_pthread_create; | |
111 | } | |
112 | ||
113 | pthread_mutex_unlock(&thread_list.lock); | |
114 | return thread; | |
115 | ||
116 | error_pthread_create: | |
117 | cds_list_del(&thread->node); | |
118 | /* Release list reference. */ | |
119 | lttng_thread_put(thread); | |
120 | pthread_mutex_unlock(&thread_list.lock); | |
b878f05a JG |
121 | /* Release initial reference. */ |
122 | lttng_thread_put(thread); | |
21fa020e | 123 | error_alloc: |
b878f05a JG |
124 | return NULL; |
125 | } | |
126 | ||
127 | bool lttng_thread_get(struct lttng_thread *thread) | |
128 | { | |
129 | return urcu_ref_get_unless_zero(&thread->ref); | |
130 | } | |
131 | ||
132 | void lttng_thread_put(struct lttng_thread *thread) | |
133 | { | |
0f68efb6 JG |
134 | if (!thread) { |
135 | return; | |
136 | } | |
b878f05a JG |
137 | assert(thread->ref.refcount); |
138 | urcu_ref_put(&thread->ref, lttng_thread_release); | |
139 | } | |
140 | ||
141 | const char *lttng_thread_get_name(const struct lttng_thread *thread) | |
142 | { | |
143 | return thread->name; | |
144 | } | |
145 | ||
146 | static | |
147 | bool _lttng_thread_shutdown(struct lttng_thread *thread) | |
148 | { | |
149 | int ret; | |
150 | void *status; | |
151 | bool result = true; | |
152 | ||
153 | DBG("Shutting down \"%s\" thread", thread->name); | |
154 | if (thread->shutdown) { | |
155 | result = thread->shutdown(thread->data); | |
156 | if (!result) { | |
157 | result = false; | |
158 | goto end; | |
159 | } | |
160 | } | |
161 | ||
162 | ret = pthread_join(thread->thread, &status); | |
163 | if (ret) { | |
164 | PERROR("Failed to join \"%s\" thread", thread->name); | |
165 | result = false; | |
19d3c73e | 166 | goto end; |
b878f05a | 167 | } |
d1ba29d2 | 168 | DBG("Joined thread \"%s\"", thread->name); |
b878f05a JG |
169 | end: |
170 | return result; | |
171 | } | |
172 | ||
173 | bool lttng_thread_shutdown(struct lttng_thread *thread) | |
174 | { | |
d1ba29d2 JG |
175 | const bool result = _lttng_thread_shutdown(thread); |
176 | ||
177 | if (result) { | |
178 | /* Release the list's reference to the thread. */ | |
179 | pthread_mutex_lock(&thread_list.lock); | |
180 | cds_list_del(&thread->node); | |
181 | lttng_thread_put(thread); | |
182 | pthread_mutex_unlock(&thread_list.lock); | |
183 | } | |
b878f05a JG |
184 | return result; |
185 | } | |
186 | ||
187 | void lttng_thread_list_shutdown_orphans(void) | |
188 | { | |
189 | struct lttng_thread *thread, *tmp; | |
190 | ||
191 | pthread_mutex_lock(&thread_list.lock); | |
192 | cds_list_for_each_entry_safe(thread, tmp, &thread_list.head, node) { | |
193 | bool result; | |
194 | const long ref = uatomic_read(&thread->ref.refcount); | |
195 | ||
196 | if (ref != 1) { | |
197 | /* | |
198 | * Other external references to the thread exist, skip. | |
199 | */ | |
200 | continue; | |
201 | } | |
202 | ||
203 | result = _lttng_thread_shutdown(thread); | |
204 | if (!result) { | |
205 | ERR("Failed to shutdown thread \"%s\"", thread->name); | |
206 | } | |
207 | } | |
208 | pthread_mutex_unlock(&thread_list.lock); | |
209 | } |