Added POSIX-style blocking I/O calls, for use by PXE TFTP API.

src/include/gpxe/posix_io.h

@@ -0,0 +1,31 @@
+#ifndef _GPXE_POSIX_IO_H
+#define _GPXE_POSIX_IO_H
+
+/** @file
+ *
+ * POSIX-like I/O
+ *
+ */
+
+#include <stdint.h>
+#include <gpxe/uaccess.h>
+
+extern int open ( const char *uri_string );
+extern ssize_t read_user ( int fd, userptr_t buffer,
+			   off_t offset, size_t len );
+extern ssize_t fsize ( int fd );
+extern int close ( int fd );
+
+/**
+ * Read data from file
+ *
+ * @v fd		File descriptor
+ * @v buf		Data buffer
+ * @v len		Maximum length to read
+ * @ret len		Actual length read, or negative error number
+ */
+static inline ssize_t read ( int fd, void *buf, size_t len ) {
+	return read_user ( fd, virt_to_user ( buf ), 0, len );
+}
+
+#endif /* _GPXE_POSIX_IO_H */