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05c06f31 PA |
1 | /* This testcase is part of GDB, the GNU debugger. |
2 | ||
88b9d363 | 3 | Copyright 2021-2022 Free Software Foundation, Inc. |
05c06f31 PA |
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 3 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, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU General Public License | |
16 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
17 | ||
18 | #define _GNU_SOURCE | |
19 | #include <assert.h> | |
20 | #include <pthread.h> | |
21 | #include <stdlib.h> | |
22 | #include <stdio.h> | |
23 | #include <unistd.h> | |
24 | #include <string.h> | |
25 | ||
26 | #define THREADS 20 | |
27 | ||
28 | static volatile unsigned int global_var = 123; | |
29 | ||
30 | /* Wrapper around pthread_create. */ | |
31 | ||
32 | static void | |
33 | create_thread (pthread_t *child, | |
34 | void *(*start_routine) (void *), void *arg) | |
35 | { | |
36 | int rc; | |
37 | ||
38 | while ((rc = pthread_create (child, NULL, start_routine, arg)) != 0) | |
39 | { | |
40 | fprintf (stderr, "unexpected error from pthread_create: %s (%d)\n", | |
41 | strerror (rc), rc); | |
42 | sleep (1); | |
43 | } | |
44 | } | |
45 | ||
46 | /* Data passed to threads on creation. This is allocated on the heap | |
47 | and ownership transferred from parent to child. */ | |
48 | ||
49 | struct thread_arg | |
50 | { | |
51 | /* The thread's parent. */ | |
52 | pthread_t parent; | |
53 | ||
54 | /* Whether to call pthread_join on the parent. */ | |
55 | int join_parent; | |
56 | }; | |
57 | ||
58 | /* Entry point for threads. */ | |
59 | ||
60 | static void * | |
61 | thread_fn (void *arg) | |
62 | { | |
63 | struct thread_arg *p = arg; | |
64 | ||
65 | /* Passing no argument makes the thread exit immediately. */ | |
66 | if (p == NULL) | |
67 | return NULL; | |
68 | ||
69 | if (p->join_parent) | |
70 | assert (pthread_join (p->parent, NULL) == 0); | |
71 | ||
72 | /* Spawn a number of threads that exit immediately, and then join | |
73 | them. The idea is to maximize the time window when we mostly | |
74 | have threads exiting. */ | |
75 | { | |
76 | pthread_t child[THREADS]; | |
77 | int i; | |
78 | ||
79 | /* Passing no argument makes the thread exit immediately. */ | |
80 | for (i = 0; i < THREADS; i++) | |
81 | create_thread (&child[i], thread_fn, NULL); | |
82 | ||
83 | for (i = 0; i < THREADS; i++) | |
84 | pthread_join (child[i], NULL); | |
85 | } | |
86 | ||
87 | /* Spawn a new thread that joins us, and exit. The idea here is to | |
88 | not have any thread that stays around forever. */ | |
89 | { | |
90 | pthread_t child; | |
91 | ||
92 | p->parent = pthread_self (); | |
93 | p->join_parent = 1; | |
94 | create_thread (&child, thread_fn, p); | |
95 | } | |
96 | ||
97 | return NULL; | |
98 | } | |
99 | ||
100 | int | |
101 | main (void) | |
102 | { | |
103 | int i; | |
104 | ||
105 | for (i = 0; i < 4; i++) | |
106 | { | |
107 | struct thread_arg *p; | |
108 | pthread_t child; | |
109 | ||
110 | p = malloc (sizeof *p); | |
111 | p->parent = pthread_self (); | |
112 | /* Only join the parent once. */ | |
113 | if (i == 0) | |
114 | p->join_parent = 1; | |
115 | else | |
116 | p->join_parent = 0; | |
117 | create_thread (&child, thread_fn, p); | |
118 | } | |
119 | ||
120 | /* Exit the leader to make sure that we can access memory with the | |
121 | leader gone. */ | |
122 | pthread_exit (NULL); | |
123 | } |