usbip: tools: Extract generic code to be shared with vudc backend

Extract the code from current stub driver backend and a common
interface for both stub driver and vudc. This allows to share most
of the usbipd code for both of them.

Based on code created in cooperation with Open Operating Systems
Student Society at University of Warsaw (O2S3@UW) consisting of:

    Igor Kotrasinski <ikotrasinsk@gmail.com>
    Karol Kosik <karo9@interia.eu>
    Ewelina Kosmider <3w3lfin@gmail.com>
    Dawid Lazarczyk <lazarczyk.dawid@gmail.com>
    Piotr Szulc <ps347277@students.mimuw.edu.pl>

Tutor and project owner:
    Krzysztof Opasiak <k.opasiak@samsung.com>

Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tools/usb/usbip/src/usbipd.c

@@ -1,6 +1,9 @@
 /*
  * Copyright (C) 2011 matt mooney <mfm@muteddisk.com>
  *               2005-2007 Takahiro Hirofuchi
+ * Copyright (C) 2015-2016 Samsung Electronics
+ *               Igor Kotrasinski <i.kotrasinsk@samsung.com>
+ *               Krzysztof Opasiak <k.opasiak@samsung.com>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -41,6 +44,7 @@
 #include <poll.h>
 
 #include "usbip_host_driver.h"
+#include "usbip_host_common.h"
 #include "usbip_common.h"
 #include "usbip_network.h"
 #include "list.h"
@@ -83,6 +87,8 @@ static const char usbipd_help_string[] =
 	"	-v, --version\n"
 	"		Show version.\n";
 
+static struct usbip_host_driver *driver;
+
 static void usbipd_help(void)
 {
 	printf("%s\n", usbipd_help_string);
@@ -107,7 +113,7 @@ static int recv_request_import(int sockfd)
 	}
 	PACK_OP_IMPORT_REQUEST(0, &req);
 
-	list_for_each(i, &host_driver->edev_list) {
+	list_for_each(i, &driver->edev_list) {
 		edev = list_entry(i, struct usbip_exported_device, node);
 		if (!strncmp(req.busid, edev->udev.busid, SYSFS_BUS_ID_SIZE)) {
 			info("found requested device: %s", req.busid);
@@ -121,7 +127,7 @@ static int recv_request_import(int sockfd)
 		usbip_net_set_nodelay(sockfd);
 
 		/* export device needs a TCP/IP socket descriptor */
-		rc = usbip_host_export_device(edev, sockfd);
+		rc = usbip_export_device(edev, sockfd);
 		if (rc < 0)
 			error = 1;
 	} else {
@@ -166,7 +172,7 @@ static int send_reply_devlist(int connfd)
 
 	reply.ndev = 0;
 	/* number of exported devices */
-	list_for_each(j, &host_driver->edev_list) {
+	list_for_each(j, &driver->edev_list) {
 		reply.ndev += 1;
 	}
 	info("exportable devices: %d", reply.ndev);
@@ -184,7 +190,7 @@ static int send_reply_devlist(int connfd)
 		return -1;
 	}
 
-	list_for_each(j, &host_driver->edev_list) {
+	list_for_each(j, &driver->edev_list) {
 		edev = list_entry(j, struct usbip_exported_device, node);
 		dump_usb_device(&edev->udev);
 		memcpy(&pdu_udev, &edev->udev, sizeof(pdu_udev));
@@ -246,7 +252,7 @@ static int recv_pdu(int connfd)
 		return -1;
 	}
 
-	ret = usbip_host_refresh_device_list();
+	ret = usbip_refresh_device_list(driver);
 	if (ret < 0) {
 		dbg("could not refresh device list: %d", ret);
 		return -1;
@@ -491,16 +497,13 @@ static int do_standalone_mode(int daemonize, int ipv4, int ipv6)
 	struct timespec timeout;
 	sigset_t sigmask;
 
-	if (usbip_host_driver_open()) {
-		err("please load " USBIP_CORE_MOD_NAME ".ko and "
-		    USBIP_HOST_DRV_NAME ".ko!");
+	if (usbip_driver_open(driver))
 		return -1;
-	}
 
 	if (daemonize) {
 		if (daemon(0, 0) < 0) {
 			err("daemonizing failed: %s", strerror(errno));
-			usbip_host_driver_close();
+			usbip_driver_close(driver);
 			return -1;
 		}
 		umask(0);
@@ -525,7 +528,7 @@ static int do_standalone_mode(int daemonize, int ipv4, int ipv6)
 
 	ai_head = do_getaddrinfo(NULL, family);
 	if (!ai_head) {
-		usbip_host_driver_close();
+		usbip_driver_close(driver);
 		return -1;
 	}
 	nsockfd = listen_all_addrinfo(ai_head, sockfdlist,
@@ -533,7 +536,7 @@ static int do_standalone_mode(int daemonize, int ipv4, int ipv6)
 	freeaddrinfo(ai_head);
 	if (nsockfd <= 0) {
 		err("failed to open a listening socket");
-		usbip_host_driver_close();
+		usbip_driver_close(driver);
 		return -1;
 	}
 
@@ -574,7 +577,7 @@ static int do_standalone_mode(int daemonize, int ipv4, int ipv6)
 
 	info("shutting down " PROGNAME);
 	free(fds);
-	usbip_host_driver_close();
+	usbip_driver_close(driver);
 
 	return 0;
 }
@@ -613,6 +616,7 @@ int main(int argc, char *argv[])
 		err("not running as root?");
 
 	cmd = cmd_standalone_mode;
+	driver = &host_driver;
 	for (;;) {
 		opt = getopt_long(argc, argv, "46DdP::t:hv", longopts, NULL);