lib: c: io: implement standard FILE and DIR interfaces

lib/libc/io/stdio/fgets.c

@@ -0,0 +1,40 @@
+#include "file.h"
+
+#include <stdio.h>
+
+char *fgets(
+	char *restrict str,
+	int count,
+	struct __opaque_file *restrict stream)
+{
+	if (stream->f_flags & (FILE_EOF | FILE_ERR)) {
+		return NULL;
+	}
+
+	size_t i = 0;
+	while (1) {
+		int c = fgetc(stream);
+
+		if (c == EOF) {
+			str[i] = 0;
+			break;
+		}
+
+		str[i++] = c;
+
+		if (c == '\n') {
+			str[i] = 0;
+			break;
+		}
+	}
+
+	if (ferr(stream)) {
+		return NULL;
+	}
+
+	if (feof(stream) && i == 0) {
+		return NULL;
+	}
+
+	return str;
+}