From: heinzm@redhat.com <heinzm@redhat.com>
Date: Wed, 27 Aug 2008 14:16:39 +0200
Subject: [md] add device-mapper message parser interface
Message-id: 20080827121637.427194187@redhat.com
O-Subject: [PATCH RHEL5.3 437180 03/11] dm-message.h.patch
Bugzilla: 437180

This patch introduces the device-mapper message parser interface.

It allows for parsing message strings calling callback functions with
parsed parameters being passed to those.

Heinz

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>

diff --git a/drivers/md/dm-message.h b/drivers/md/dm-message.h
new file mode 100644
index 0000000..ddc52c7
--- /dev/null
+++ b/drivers/md/dm-message.h
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2007,2008 Red Hat, Inc. All rights reserved.
+ *
+ * Module Author: Heinz Mauelshagen <heinzm@redhat.com>
+ *
+ * This file is released under the GPL.
+ *
+ */
+
+#ifndef DM_MESSAGE_H
+#define DM_MESSAGE_H
+
+/* Factor out to dm.h. */
+/* Reference to array end. */
+#define ARRAY_END(a)    ((a) + ARRAY_SIZE(a))
+
+/* Message return bits. */
+enum dm_message_return {
+	dm_msg_ret_ambiguous,		/* Action ambiguous. */
+	dm_msg_ret_inval,		/* Action invalid. */
+	dm_msg_ret_undef,		/* Action undefined. */
+
+	dm_msg_ret_option,		/* Option error. */
+	dm_msg_ret_arg,			/* Argument error. */
+	dm_msg_ret_argcount,		/* Argument count error. */
+};
+
+/* Message argument type conversions. */
+enum dm_message_argument_type {
+	dm_msg_base_t,		/* Basename string. */
+	dm_msg_str_t,		/* String. */
+	dm_msg_int_t,		/* Signed int. */
+	dm_msg_uint_t,		/* Unsigned int. */
+	dm_msg_uint64_t,	/* Unsigned int 64. */
+};
+
+/* A message option. */
+struct dm_message_option {
+	unsigned num_options;
+	char **options;
+	unsigned long *actions;
+};
+
+/* Message arguments and types. */
+struct dm_message_argument {
+	unsigned num_args;
+	unsigned long **ptr;
+	enum dm_message_argument_type types[];
+};
+
+/* Client message. */
+struct dm_msg {
+	unsigned long action;		/* Identified action. */
+	unsigned long ret;		/* Return bits. */
+	unsigned num_specs;		/* # of sepcifications listed. */
+	struct dm_msg_spec *specs;	/* Specification list. */
+	struct dm_msg_spec *spec;	/* Specification selected. */
+};
+
+/* Secification of the message. */
+struct dm_msg_spec {
+	const char *cmd;	/* Name of the command (i.e. 'bandwidth'). */
+	unsigned long action;
+	struct dm_message_option *options;
+	struct dm_message_argument *args;
+	unsigned long parm;	/* Parameter to pass through to callback. */
+	/* Function to process for action. */
+	int (*f) (struct dm_msg *msg, void *context);
+};
+
+/* Parameter access macros. */
+#define	DM_MSG_PARM(msg) ((msg)->spec->parm)
+
+#define	DM_MSG_STR_ARGS(msg, idx) ((char*) *(msg)->spec->args->ptr[idx])
+#define	DM_MSG_INT_ARGS(msg, idx) ((int) *(msg)->spec->args->ptr[idx])
+#define	DM_MSG_UINT_ARGS(msg, idx) ((unsigned) DM_MSG_INT_ARG(msg, idx))
+#define	DM_MSG_UINT64_ARGS(msg, idx) ((uint64_t)  *(msg)->spec->args->ptr[idx])
+
+#define	DM_MSG_STR_ARG(msg)	DM_MSG_STR_ARGS(msg, 0)
+#define	DM_MSG_INT_ARG(msg)	DM_MSG_INT_ARGS(msg, 0)
+#define	DM_MSG_UINT_ARG(msg)	DM_MSG_UINT_ARGS(msg, 0)
+#define	DM_MSG_UINT64_ARG(msg)	DM_MSG_UINT64_ARGS(msg, 0)
+
+
+/* Parse a message and its options and optionally call a function back. */
+int dm_message_parse(const char *caller, struct dm_msg *msg, void *context,
+		     int argc, char **argv);
+
+#endif