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Initialize the mutex before making us of it from many threads. Prevents
a race in which one thread is currently initializing the mutex which is not an atomic operation whereas another thread tries to use it too early. With and ok schwarze@
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anton
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Apr 3, 2022
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,4 +1,4 @@ | ||
| /* $OpenBSD: uselocale.c,v 1.5 2017/08/16 13:52:50 schwarze Exp $ */ | ||
| /* $OpenBSD: uselocale.c,v 1.6 2022/04/03 16:52:50 anton Exp $ */ | ||
| /* | ||
| * Copyright (c) 2017 Ingo Schwarze <[email protected]> | ||
| * | ||
|
|
@@ -170,6 +170,10 @@ _test_MB_CUR_MAX(int line, int ee, size_t ar) | |
| #define TEST_R(Fn, ...) _test_##Fn(__LINE__, 0, __VA_ARGS__) | ||
| #define TEST_ER(Fn, ...) _test_##Fn(__LINE__, __VA_ARGS__) | ||
|
|
||
| static pthread_mutex_t mtx; | ||
| static pthread_mutexattr_t mtxattr; | ||
| static pthread_cond_t cond; | ||
|
|
||
| /* | ||
| * SWITCH_SIGNAL wakes the other thread. | ||
| * SWITCH_WAIT goes to sleep. | ||
|
|
@@ -179,40 +183,21 @@ _test_MB_CUR_MAX(int line, int ee, size_t ar) | |
| static void | ||
| switch_thread(int step, int flags) | ||
| { | ||
| static pthread_mutexattr_t ma; | ||
| static struct timespec t; | ||
| static pthread_cond_t *c; | ||
| static pthread_mutex_t *m; | ||
| int irc; | ||
|
|
||
| if (m == NULL) { | ||
| if ((m = malloc(sizeof(*m))) == NULL) | ||
| err(1, NULL); | ||
| if ((irc = pthread_mutexattr_init(&ma)) != 0) | ||
| errc(1, irc, "pthread_mutexattr_init"); | ||
| if ((irc = pthread_mutexattr_settype(&ma, | ||
| PTHREAD_MUTEX_STRICT_NP)) != 0) | ||
| errc(1, irc, "pthread_mutexattr_settype"); | ||
| if ((irc = pthread_mutex_init(m, &ma)) != 0) | ||
| errc(1, irc, "pthread_mutex_init"); | ||
| } | ||
| if (c == NULL) { | ||
| if ((c = malloc(sizeof(*c))) == NULL) | ||
| err(1, NULL); | ||
| if ((irc = pthread_cond_init(c, NULL)) != 0) | ||
| errc(1, irc, "pthread_cond_init"); | ||
| } | ||
| struct timespec t; | ||
| int irc; | ||
|
|
||
| if (flags & SWITCH_SIGNAL) { | ||
| if ((irc = pthread_cond_signal(c)) != 0) | ||
| if ((irc = pthread_cond_signal(&cond)) != 0) | ||
| errc(1, irc, "pthread_cond_signal(%d)", step); | ||
| } | ||
| if (flags & SWITCH_WAIT) { | ||
| if ((irc = pthread_mutex_trylock(m)) != 0) | ||
| if ((irc = pthread_mutex_trylock(&mtx)) != 0) | ||
| errc(1, irc, "pthread_mutex_trylock(%d)", step); | ||
| t.tv_sec = time(NULL) + 2; | ||
| if ((irc = pthread_cond_timedwait(c, m, &t)) != 0) | ||
| t.tv_nsec = 0; | ||
| if ((irc = pthread_cond_timedwait(&cond, &mtx, &t)) != 0) | ||
| errc(1, irc, "pthread_cond_timedwait(%d)", step); | ||
| if ((irc = pthread_mutex_unlock(m)) != 0) | ||
| if ((irc = pthread_mutex_unlock(&mtx)) != 0) | ||
| errc(1, irc, "pthread_mutex_unlock(%d)", step); | ||
| } | ||
| } | ||
|
|
@@ -442,6 +427,16 @@ main(void) | |
| unsetenv("LC_MESSAGES"); | ||
| unsetenv("LANG"); | ||
|
|
||
| if ((irc = pthread_mutexattr_init(&mtxattr)) != 0) | ||
| errc(1, irc, "pthread_mutexattr_init"); | ||
| if ((irc = pthread_mutexattr_settype(&mtxattr, | ||
| PTHREAD_MUTEX_STRICT_NP)) != 0) | ||
| errc(1, irc, "pthread_mutexattr_settype"); | ||
| if ((irc = pthread_mutex_init(&mtx, &mtxattr)) != 0) | ||
| errc(1, irc, "pthread_mutex_init"); | ||
| if ((irc = pthread_cond_init(&cond, NULL)) != 0) | ||
| errc(1, irc, "pthread_cond_init"); | ||
|
|
||
| /* First let the child do some tests. */ | ||
| if ((irc = pthread_create(&child_thread, NULL, child_func, NULL)) != 0) | ||
| errc(1, irc, "pthread_create"); | ||
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||