3 files changed, 45 insertions, 0 deletions
diff --git a/system/lib/libc/musl/src/stdio/__overflow.c b/system/lib/libc/musl/src/stdio/__overflow.c
new file mode 100644
index 00000000..3bb37923
--- /dev/null
+++ b/system/lib/libc/musl/src/stdio/__overflow.c
@@ -0,0 +1,10 @@
+#include "stdio_impl.h"
+
+int __overflow(FILE *f, int _c)
+{
+	unsigned char c = _c;
+	if (!f->wend && __towrite(f)) return EOF;
+	if (f->wpos < f->wend && c != f->lbf) return *f->wpos++ = c;
+	if (f->write(f, &c, 1)!=1) return EOF;
+	return c;
+}
diff --git a/system/lib/libc/musl/src/stdio/__toread.c b/system/lib/libc/musl/src/stdio/__toread.c
new file mode 100644
index 00000000..2e804f64
--- /dev/null
+++ b/system/lib/libc/musl/src/stdio/__toread.c
@@ -0,0 +1,24 @@
+#include <stdio_impl.h>
+
+int __toread(FILE *f)
+{
+	f->mode |= f->mode-1;
+	if (f->wpos > f->buf) f->write(f, 0, 0);
+	f->wpos = f->wbase = f->wend = 0;
+	if (f->flags & (F_EOF|F_NORD)) {
+		if (f->flags & F_NORD) f->flags |= F_ERR;
+		return EOF;
+	}
+	f->rpos = f->rend = f->buf;
+	return 0;
+}
+
+static const int dummy = 0;
+weak_alias(dummy, __towrite_used);
+
+void __stdio_exit(void);
+
+void __seek_on_exit()
+{
+	if (!__towrite_used) __stdio_exit();
+}
diff --git a/system/lib/libc/musl/src/stdio/__uflow.c b/system/lib/libc/musl/src/stdio/__uflow.c
new file mode 100644
index 00000000..e28922c2
--- /dev/null
+++ b/system/lib/libc/musl/src/stdio/__uflow.c
@@ -0,0 +1,11 @@
+#include "stdio_impl.h"
+
+/* This function will never be called if there is already data
+ * buffered for reading. Thus we can get by with very few branches. */
+
+int __uflow(FILE *f)
+{
+	unsigned char c;
+	if ((f->rend || !__toread(f)) && f->read(f, &c, 1)==1) return c;
+	return EOF;
+}