Add a stub implementation of condvars

Makefile

@@ -290,6 +290,10 @@ LIBC_TOP_HALF_MUSL_SOURCES += \
         thread/pthread_barrierattr_destroy.c \
         thread/pthread_barrierattr_init.c \
         thread/pthread_barrierattr_setpshared.c \
+        thread/pthread_condattr_destroy.c \
+        thread/pthread_condattr_init.c \
+        thread/pthread_condattr_setclock.c \
+        thread/pthread_condattr_setpshared.c \
         thread/pthread_mutex_destroy.c \
         thread/pthread_mutex_init.c \
         thread/pthread_mutexattr_destroy.c \
@@ -322,10 +326,6 @@ LIBC_TOP_HALF_MUSL_SOURCES += \
         thread/pthread_cond_signal.c \
         thread/pthread_cond_timedwait.c \
         thread/pthread_cond_wait.c \
-        thread/pthread_condattr_destroy.c \
-        thread/pthread_condattr_init.c \
-        thread/pthread_condattr_setclock.c \
-        thread/pthread_condattr_setpshared.c \
         thread/pthread_create.c \
         thread/pthread_detach.c \
         thread/pthread_equal.c \
@@ -376,6 +376,7 @@ ifeq ($(THREAD_MODEL), single)
 # pthreads stubs for single-threaded environment
 LIBC_TOP_HALF_MUSL_SOURCES += \
     $(STUB_PTHREADS_DIR)/barrier.c \
+    $(STUB_PTHREADS_DIR)/condvar.c \
     $(STUB_PTHREADS_DIR)/mutex.c \
     $(STUB_PTHREADS_DIR)/stub-pthreads-good.c
 endif

expected/wasm32-wasip1/defined-symbols.txt

@@ -178,6 +178,7 @@ __pow_log_data
 __powf_log2_data
 __progname
 __progname_full
+__pthread_cond_timedwait
 __pthread_mutex_consistent
 __pthread_mutex_lock
 __pthread_mutex_timedlock
@@ -949,8 +950,18 @@ pthread_barrierattr_destroy
 pthread_barrierattr_getpshared
 pthread_barrierattr_init
 pthread_barrierattr_setpshared
+pthread_cond_broadcast
+pthread_cond_destroy
+pthread_cond_init
+pthread_cond_signal
+pthread_cond_timedwait
+pthread_cond_wait
+pthread_condattr_destroy
 pthread_condattr_getclock
 pthread_condattr_getpshared
+pthread_condattr_init
+pthread_condattr_setclock
+pthread_condattr_setpshared
 pthread_mutex_consistent
 pthread_mutex_destroy
 pthread_mutex_init

expected/wasm32-wasip2/defined-symbols.txt

@@ -181,6 +181,7 @@ __pow_log_data
 __powf_log2_data
 __progname
 __progname_full
+__pthread_cond_timedwait
 __pthread_mutex_consistent
 __pthread_mutex_lock
 __pthread_mutex_timedlock
@@ -1082,8 +1083,18 @@ pthread_barrierattr_destroy
 pthread_barrierattr_getpshared
 pthread_barrierattr_init
 pthread_barrierattr_setpshared
+pthread_cond_broadcast
+pthread_cond_destroy
+pthread_cond_init
+pthread_cond_signal
+pthread_cond_timedwait
+pthread_cond_wait
+pthread_condattr_destroy
 pthread_condattr_getclock
 pthread_condattr_getpshared
+pthread_condattr_init
+pthread_condattr_setclock
+pthread_condattr_setpshared
 pthread_mutex_consistent
 pthread_mutex_destroy
 pthread_mutex_init

stub-pthreads/condvar.c

@@ -0,0 +1,36 @@
+#include "pthread_impl.h"
+#include <time.h>
+
+int pthread_cond_init(pthread_cond_t *restrict c, const pthread_condattr_t *restrict a)
+{
+	return 0;
+}
+int pthread_cond_destroy(pthread_cond_t *c)
+{
+	return 0;
+}
+int pthread_cond_broadcast(pthread_cond_t *c)
+{
+	return 0;
+}
+int pthread_cond_signal(pthread_cond_t *c)
+{
+	return 0;
+}
+int pthread_cond_wait(pthread_cond_t *restrict c, pthread_mutex_t *restrict m)
+{
+	/* Because there is no other thread that can signal us, this is a deadlock immediately.
+	The other possible choice is to return immediately (spurious wakeup), but that is likely to
+	just result in the program spinning forever on a condition that cannot become true. */
+	__builtin_trap();
+}
+int __pthread_cond_timedwait(pthread_cond_t *restrict c, pthread_mutex_t *restrict m, const struct timespec *restrict ts)
+{
+	/* Error check mutexes must detect if they're not locked (UB for others) */
+	if (!m->_m_count) return EPERM;
+	int ret = clock_nanosleep(CLOCK_REALTIME, TIMER_ABSTIME, ts, 0);
+	if (ret == 0) return ETIMEDOUT;
+	if (ret != EINTR) return ret;
+	return 0;
+}
+weak_alias(__pthread_cond_timedwait, pthread_cond_timedwait);