Adding upstream version 0.0~git20221206.8b7148f.upstream/0.0_git20221206.8b7148f

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 29 insertions, 0 deletions

diff --git a/libc-top-half/musl/src/stdio/getc.h b/libc-top-half/musl/src/stdio/getc.h
new file mode 100644
index 0000000..e62e3f0
--- /dev/null
+++ b/libc-top-half/musl/src/stdio/getc.h
@@ -0,0 +1,29 @@
+#include "stdio_impl.h"
+#if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT)
+#include "pthread_impl.h"
+
+#ifdef __GNUC__
+__attribute__((__noinline__))
+#endif
+static int locking_getc(FILE *f)
+{
+	if (a_cas(&f->lock, 0, MAYBE_WAITERS-1)) __lockfile(f);
+	int c = getc_unlocked(f);
+	if (a_swap(&f->lock, 0) & MAYBE_WAITERS)
+		__wake(&f->lock, 1, 1);
+	return c;
+}
+#endif
+
+static inline int do_getc(FILE *f)
+{
+#if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT)
+	int l = f->lock;
+	if (l < 0 || l && (l & ~MAYBE_WAITERS) == __pthread_self()->tid)
+		return getc_unlocked(f);
+	return locking_getc(f);
+#else
+	// With no threads, locking is unnecessary.
+	return getc_unlocked(f);
+#endif
+}