Make read_user() non-blocking, and add select() call.

1 files changed, 54 insertions, 0 deletions

diff --git a/src/include/gpxe/posix_io.h b/src/include/gpxe/posix_io.h
index a5cf0c753..9984db005 100644
--- a/src/include/gpxe/posix_io.h
+++ b/src/include/gpxe/posix_io.h
@@ -10,13 +10,67 @@
 #include <stdint.h>
 #include <gpxe/uaccess.h>
 
+/** Minimum file descriptor that will ever be allocated */
+#define POSIX_FD_MIN ( 1 )
+
+/** Maximum file descriptor that will ever be allocated */
+#define POSIX_FD_MAX ( 31 )
+
+/** File descriptor set as used for select() */
+typedef uint32_t fd_set;
+
 extern int open ( const char *uri_string );
 extern ssize_t read_user ( int fd, userptr_t buffer,
 			   off_t offset, size_t len );
+extern int select ( fd_set *readfds, int wait );
 extern ssize_t fsize ( int fd );
 extern int close ( int fd );
 
 /**
+ * Zero a file descriptor set
+ *
+ * @v set		File descriptor set
+ */
+static inline __attribute__ (( always_inline )) void
+FD_ZERO ( fd_set *set ) {
+	*set = 0;
+}
+
+/**
+ * Set a bit within a file descriptor set
+ *
+ * @v fd		File descriptor
+ * @v set		File descriptor set
+ */
+static inline __attribute__ (( always_inline )) void
+FD_SET ( int fd, fd_set *set ) {
+	*set |= ( 1 << fd );
+}
+
+/**
+ * Clear a bit within a file descriptor set
+ *
+ * @v fd		File descriptor
+ * @v set		File descriptor set
+ */
+static inline __attribute__ (( always_inline )) void
+FD_CLR ( int fd, fd_set *set ) {
+	*set &= ~( 1 << fd );
+}
+
+/**
+ * Test a bit within a file descriptor set
+ *
+ * @v fd		File descriptor
+ * @v set		File descriptor set
+ * @ret is_set		Corresponding bit is set
+ */
+static inline __attribute__ (( always_inline )) int
+FD_ISSET ( int fd, fd_set *set ) {
+	return ( *set & ( 1 << fd ) );
+}
+
+/**
  * Read data from file
  *
  * @v fd		File descriptor