1 files changed, 61 insertions, 0 deletions
diff --git a/src/core/errno.c b/src/core/errno.c
new file mode 100644
index 000000000..83c8564bc
--- /dev/null
+++ b/src/core/errno.c
@@ -0,0 +1,61 @@
+#include "etherboot.h"
+#include "errno.h"
+#include "vsprintf.h"
+
+/** @file
+ *
+ * Error codes and descriptions.
+ *
+ * This file provides the global variable #errno and the function
+ * strerror().  These function much like their standard C library
+ * equivalents.
+ *
+ * The error numbers used by Etherboot are a superset of those defined
+ * by the PXE specification version 2.1.  See errno.h for a listing of
+ * the error values.
+ *
+ * To save space in ROM images, error string tables are optional.  Use
+ * the ERRORMSG_XXX options in config.h to select which error string
+ * tables you want to include.  If an error string table is omitted,
+ * strerror() will simply return the text "Error 0x<errno>".
+ *
+ */
+
+/**
+ * Global "last error" number.
+ *
+ * This is valid only when a function has just returned indicating a
+ * failure.
+ *
+ */
+int errno;
+
+static struct errortab errortab_start[0] __table_start(errortab);
+static struct errortab errortab_end[0] __table_end(errortab);
+
+/**
+ * Retrieve string representation of error number.
+ *
+ * @v errno		Error number
+ * @ret strerror	Pointer to error text
+ *
+ * If the error is not found in the linked-in error tables, generates
+ * a generic "Error 0x<errno>" message.
+ *
+ * The pointer returned by strerror() is valid only until the next
+ * call to strerror().
+ *
+ */
+const char * strerror ( int errno ) {
+	static char *generic_message = "Error 0x0000";
+	struct errortab *errortab;
+
+	for ( errortab = errortab_start ; errortab < errortab_end ;
+	      errortab++ ) {
+		if ( errortab->errno == errno )
+			return errortab->text;
+	}
+
+	sprintf ( generic_message + 8, "%hx", errno );
+	return generic_message;
+}