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 | ||
64 | DBG("Launching \"%s\" thread", thread->name); | |
65 | ret = thread->entry(thread->data); | |
66 | DBG("Thread \"%s\" has returned", thread->name); | |
67 | return ret; | |
68 | } | |
69 | ||
70 | struct lttng_thread *lttng_thread_create(const char *name, | |
71 | lttng_thread_entry_point entry, | |
72 | lttng_thread_shutdown_cb shutdown, | |
73 | lttng_thread_cleanup_cb cleanup, | |
74 | void *thread_data) | |
75 | { | |
76 | int ret; | |
77 | struct lttng_thread *thread; | |
78 | ||
79 | thread = zmalloc(sizeof(*thread)); | |
80 | if (!thread) { | |
21fa020e | 81 | goto error_alloc; |
b878f05a JG |
82 | } |
83 | ||
84 | urcu_ref_init(&thread->ref); | |
85 | CDS_INIT_LIST_HEAD(&thread->node); | |
86 | /* | |
87 | * Thread names are assumed to be statically allocated strings. | |
88 | * It is unnecessary to copy this attribute. | |
89 | */ | |
90 | thread->name = name; | |
91 | thread->entry = entry; | |
92 | thread->shutdown = shutdown; | |
93 | thread->cleanup = cleanup; | |
94 | thread->data = thread_data; | |
95 | ||
96 | pthread_mutex_lock(&thread_list.lock); | |
97 | /* | |
98 | * Add the thread at the head of the list to shutdown threads in the | |
99 | * opposite order of their creation. A reference is taken for the | |
100 | * thread list which will be released on shutdown of the thread. | |
101 | */ | |
102 | cds_list_add(&thread->node, &thread_list.head); | |
103 | (void) lttng_thread_get(thread); | |
104 | ||
105 | ret = pthread_create(&thread->thread, default_pthread_attr(), | |
106 | launch_thread, thread); | |
107 | if (ret) { | |
108 | PERROR("Failed to create \"%s\" thread", thread->name); | |
109 | goto error_pthread_create; | |
110 | } | |
111 | ||
112 | pthread_mutex_unlock(&thread_list.lock); | |
113 | return thread; | |
114 | ||
115 | error_pthread_create: | |
116 | cds_list_del(&thread->node); | |
117 | /* Release list reference. */ | |
118 | lttng_thread_put(thread); | |
119 | pthread_mutex_unlock(&thread_list.lock); | |
b878f05a JG |
120 | /* Release initial reference. */ |
121 | lttng_thread_put(thread); | |
21fa020e | 122 | error_alloc: |
b878f05a JG |
123 | return NULL; |
124 | } | |
125 | ||
126 | bool lttng_thread_get(struct lttng_thread *thread) | |
127 | { | |
128 | return urcu_ref_get_unless_zero(&thread->ref); | |
129 | } | |
130 | ||
131 | void lttng_thread_put(struct lttng_thread *thread) | |
132 | { | |
0f68efb6 JG |
133 | if (!thread) { |
134 | return; | |
135 | } | |
b878f05a JG |
136 | assert(thread->ref.refcount); |
137 | urcu_ref_put(&thread->ref, lttng_thread_release); | |
138 | } | |
139 | ||
140 | const char *lttng_thread_get_name(const struct lttng_thread *thread) | |
141 | { | |
142 | return thread->name; | |
143 | } | |
144 | ||
145 | static | |
146 | bool _lttng_thread_shutdown(struct lttng_thread *thread) | |
147 | { | |
148 | int ret; | |
149 | void *status; | |
150 | bool result = true; | |
151 | ||
152 | DBG("Shutting down \"%s\" thread", thread->name); | |
153 | if (thread->shutdown) { | |
154 | result = thread->shutdown(thread->data); | |
155 | if (!result) { | |
156 | result = false; | |
157 | goto end; | |
158 | } | |
159 | } | |
160 | ||
161 | ret = pthread_join(thread->thread, &status); | |
162 | if (ret) { | |
163 | PERROR("Failed to join \"%s\" thread", thread->name); | |
164 | result = false; | |
19d3c73e | 165 | goto end; |
b878f05a JG |
166 | } |
167 | /* Release the list's reference to the thread. */ | |
168 | cds_list_del(&thread->node); | |
169 | lttng_thread_put(thread); | |
170 | end: | |
171 | return result; | |
172 | } | |
173 | ||
174 | bool lttng_thread_shutdown(struct lttng_thread *thread) | |
175 | { | |
176 | bool result; | |
177 | ||
178 | pthread_mutex_lock(&thread_list.lock); | |
179 | result = _lttng_thread_shutdown(thread); | |
180 | pthread_mutex_unlock(&thread_list.lock); | |
181 | return result; | |
182 | } | |
183 | ||
184 | void lttng_thread_list_shutdown_orphans(void) | |
185 | { | |
186 | struct lttng_thread *thread, *tmp; | |
187 | ||
188 | pthread_mutex_lock(&thread_list.lock); | |
189 | cds_list_for_each_entry_safe(thread, tmp, &thread_list.head, node) { | |
190 | bool result; | |
191 | const long ref = uatomic_read(&thread->ref.refcount); | |
192 | ||
193 | if (ref != 1) { | |
194 | /* | |
195 | * Other external references to the thread exist, skip. | |
196 | */ | |
197 | continue; | |
198 | } | |
199 | ||
200 | result = _lttng_thread_shutdown(thread); | |
201 | if (!result) { | |
202 | ERR("Failed to shutdown thread \"%s\"", thread->name); | |
203 | } | |
204 | } | |
205 | pthread_mutex_unlock(&thread_list.lock); | |
206 | } |