4 files changed, 30 insertions, 15 deletions
diff --git a/src/stdio/fgetc.c b/src/stdio/fgetc.c
index e1224164..2578afcc 100644
--- a/src/stdio/fgetc.c
+++ b/src/stdio/fgetc.c
@@ -1,11 +1,7 @@
-#include "stdio_impl.h"
+#include <stdio.h>
+#include "getc.h"
 
 int fgetc(FILE *f)
 {
-	int c;
-	if (f->lock < 0 || !__lockfile(f))
-		return getc_unlocked(f);
-	c = getc_unlocked(f);
-	__unlockfile(f);
-	return c;
+	return do_getc(f);
 }
diff --git a/src/stdio/getc.c b/src/stdio/getc.c
index b3f351d1..8409fc23 100644
--- a/src/stdio/getc.c
+++ b/src/stdio/getc.c
@@ -1,13 +1,9 @@
-#include "stdio_impl.h"
+#include <stdio.h>
+#include "getc.h"
 
 int getc(FILE *f)
 {
-	int c;
-	if (f->lock < 0 || !__lockfile(f))
-		return getc_unlocked(f);
-	c = getc_unlocked(f);
-	__unlockfile(f);
-	return c;
+	return do_getc(f);
 }
 
 weak_alias(getc, _IO_getc);
diff --git a/src/stdio/getc.h b/src/stdio/getc.h
new file mode 100644
index 00000000..0657ab6f
--- /dev/null
+++ b/src/stdio/getc.h
@@ -0,0 +1,22 @@
+#include "stdio_impl.h"
+#include "pthread_impl.h"
+
+#ifdef __GNUC__
+__attribute__((__noinline__))
+#endif
+static int locking_getc(FILE *f, int tid)
+{
+	if (a_cas(&f->lock, 0, tid)) __lockfile(f);
+	int c = getc_unlocked(f);
+	if (a_swap(&f->lock, 0) & MAYBE_WAITERS)
+		__wake(&f->lock, 1, 1);
+	return c;
+}
+
+static inline int do_getc(FILE *f)
+{
+	int tid, l = f->lock;
+	if (l < 0 || (l & ~MAYBE_WAITERS) == (tid=__pthread_self()->tid))
+		return getc_unlocked(f);
+	return locking_getc(f, tid);
+}
diff --git a/src/stdio/getchar.c b/src/stdio/getchar.c
index c1012658..df395ca9 100644
--- a/src/stdio/getchar.c
+++ b/src/stdio/getchar.c
@@ -1,6 +1,7 @@
 #include <stdio.h>
+#include "getc.h"
 
 int getchar(void)
 {
-	return fgetc(stdin);
+	return do_getc(stdin);
 }