[9/9] petitboot: Make device instance constant

--- a/discover/device-handler.c
+++ b/discover/device-handler.c
@@ -54,7 +54,7 @@  static struct device device = {
 };
 
 int device_handler_get_current_devices(struct device_handler *handler,
-		struct device **devices)
+		const struct device **devices)
 
 {
 	*devices = &device;
--- a/discover/device-handler.h
+++ b/discover/device-handler.h
@@ -25,7 +25,7 @@  struct device_handler *device_handler_in
 void device_handler_destroy(struct device_handler *devices);
 
 int device_handler_get_current_devices(struct device_handler *handler,
-		struct device **devices);
+		const struct device **devices);
 
 int device_handler_event(struct device_handler *handler,
 		struct udev_event *event);
--- a/discover/discover-server.c
+++ b/discover/discover-server.c
@@ -89,7 +89,7 @@  static int client_write_message(struct d
 }
 
 static int write_add_message(struct discover_server *server,
-		struct client *client, struct device *dev)
+		struct client *client, const struct device *dev)
 {
 	struct pb_protocol_message *message;
 	int len;
@@ -127,7 +127,7 @@  static int write_remove_message(struct d
 static int discover_server_process(void *arg)
 {
 	struct discover_server *server = arg;
-	struct device *devices;
+	const struct device *devices;
 	struct client *client;
 	int fd, i, n_devices;
 
--- a/lib/pb-protocol/pb-protocol.c
+++ b/lib/pb-protocol/pb-protocol.c
@@ -85,7 +85,8 @@  int pb_protocol_serialise_string(char *p
  * @param[out] str	Pointer to resuling string
  * @return		zero on success, non-zero on failure
  */
-static int read_string(void *ctx, char **pos, unsigned int *len, char **str)
+static int read_string(void *ctx, const char **pos, unsigned int *len,
+	char **str)
 {
 	uint32_t str_len, read_len;
 
@@ -113,9 +114,10 @@  static int read_string(void *ctx, char *
 }
 
 char *pb_protocol_deserialise_string(void *ctx,
-		struct pb_protocol_message *message)
+		const struct pb_protocol_message *message)
 {
-	char *buf, *str;
+	const char *buf;
+	char *str;
 	unsigned int len;
 
 	len = message->payload_len;
@@ -134,7 +136,7 @@  static int optional_strlen(const char *s
 	return strlen(str);
 }
 
-int pb_protocol_device_len(struct device *dev)
+int pb_protocol_device_len(const struct device *dev)
 {
 	struct boot_option *opt;
 	int len;
@@ -158,7 +160,7 @@  int pb_protocol_device_len(struct device
 	return len;
 }
 
-int pb_protocol_serialise_device(struct device *dev, char *buf, int buf_len)
+int pb_protocol_serialise_device(const struct device *dev, char *buf, int buf_len)
 {
 	struct boot_option *opt;
 	uint32_t n;
@@ -277,10 +279,10 @@  struct pb_protocol_message *pb_protocol_
 
 
 struct device *pb_protocol_deserialise_device(void *ctx,
-		struct pb_protocol_message *message)
+		const struct pb_protocol_message *message)
 {
 	struct device *dev;
-	char *pos;
+	const char *pos;
 	int i, n_options;
 	unsigned int len;
 
--- a/lib/pb-protocol/pb-protocol.h
+++ b/lib/pb-protocol/pb-protocol.h
@@ -43,13 +43,13 @@  struct boot_option {
 
 struct boot_option *boot_option_copy(void* ctx, const struct boot_option *opt);
 
-int pb_protocol_device_len(struct device *dev);
+int pb_protocol_device_len(const struct device *dev);
 
 int pb_protocol_serialise_string(char *pos, const char *str);
 char *pb_protocol_deserialise_string(void *ctx,
-		struct pb_protocol_message *message);
+		const struct pb_protocol_message *message);
 
-int pb_protocol_serialise_device(struct device *dev, char *buf, int buf_len);
+int pb_protocol_serialise_device(const struct device *dev, char *buf, int buf_len);
 
 int pb_protocol_write_message(int fd, struct pb_protocol_message *message);
 
@@ -59,6 +59,6 @@  struct pb_protocol_message *pb_protocol_
 struct pb_protocol_message *pb_protocol_read_message(void *ctx, int fd);
 
 struct device *pb_protocol_deserialise_device(void *ctx,
-		struct pb_protocol_message *message);
+		const struct pb_protocol_message *message);
 
 #endif /* _PB_PROTOCOL_H */