Drivers: hv: Implement the file copy service

Implement the file copy service for Linux guests on Hyper-V. This permits the
host to copy a file (over VMBUS) into the guest. This facility is part of
"guest integration services" supported on the Windows platform.
Here is a link that provides additional details on this functionality:

http://technet.microsoft.com/en-us/library/dn464282.aspx

In V1 version of the patch I have addressed comments from
Olaf Hering <olaf@aepfle.de> and Dan Carpenter <dan.carpenter@oracle.com>

In V2 version of this patch I did some minor cleanup (making some globals
static). In V4 version of the patch I have addressed all of Olaf's
most recent set of comments/concerns.

In V5 version of the patch I had addressed Greg's most recent comments.
I would like to thank Greg for suggesting that I use misc device; it has
significantly simplified the code.

In V6 version of the patch I have cleaned up error message based on Olaf's
comments. I have also rebased the patch based on the current tip.

In this version of the patch, I have addressed the latest comments from Greg.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hv/Makefile

@@ -5,4 +5,4 @@ obj-$(CONFIG_HYPERV_BALLOON)	+= hv_balloon.o
 hv_vmbus-y := vmbus_drv.o \
 		 hv.o connection.o channel.o \
 		 channel_mgmt.o ring_buffer.o
-hv_utils-y := hv_util.o hv_kvp.o hv_snapshot.o
+hv_utils-y := hv_util.o hv_kvp.o hv_snapshot.o hv_fcopy.o

drivers/hv/hv_util.c

@@ -28,6 +28,7 @@
 #include <linux/reboot.h>
 #include <linux/hyperv.h>
 
+#include "hyperv_vmbus.h"
 
 #define SD_MAJOR	3
 #define SD_MINOR	0
@@ -82,6 +83,12 @@ static struct hv_util_service util_vss = {
 	.util_deinit = hv_vss_deinit,
 };
 
+static struct hv_util_service util_fcopy = {
+	.util_cb = hv_fcopy_onchannelcallback,
+	.util_init = hv_fcopy_init,
+	.util_deinit = hv_fcopy_deinit,
+};
+
 static void perform_shutdown(struct work_struct *dummy)
 {
 	orderly_poweroff(true);
@@ -401,6 +408,10 @@ static const struct hv_vmbus_device_id id_table[] = {
 	{ HV_VSS_GUID,
 	  .driver_data = (unsigned long)&util_vss
 	},
+	/* File copy GUID */
+	{ HV_FCOPY_GUID,
+	  .driver_data = (unsigned long)&util_fcopy
+	},
 	{ },
 };
 

drivers/hv/hyperv_vmbus.h

@@ -669,5 +669,9 @@ int vmbus_set_event(struct vmbus_channel *channel);
 
 void vmbus_on_event(unsigned long data);
 
+int hv_fcopy_init(struct hv_util_service *);
+void hv_fcopy_deinit(void);
+void hv_fcopy_onchannelcallback(void *);
+
 
 #endif /* _HYPERV_VMBUS_H */

include/linux/hyperv.h

@@ -30,7 +30,6 @@
 #include <linux/types.h>
 #include <linux/scatterlist.h>
 #include <linux/list.h>
-#include <linux/uuid.h>
 #include <linux/timer.h>
 #include <linux/workqueue.h>
 #include <linux/completion.h>
@@ -1049,6 +1048,17 @@ void vmbus_driver_unregister(struct hv_driver *hv_driver);
 			0xB7, 0x6B, 0x6F, 0xD0, 0xBE, 0x52, 0x8C, 0xDA \
 		}
 
+/*
+ * Guest File Copy Service
+ * {34D14BE3-DEE4-41c8-9AE7-6B174977C192}
+ */
+
+#define HV_FCOPY_GUID \
+	.guid = { \
+			0xE3, 0x4B, 0xD1, 0x34, 0xE4, 0xDE, 0xC8, 0x41, \
+			0x9A, 0xE7, 0x6B, 0x17, 0x49, 0x77, 0xC1, 0x92 \
+		}
+
 /*
  * Common header for Hyper-V ICs
  */

include/uapi/linux/hyperv.h

@@ -25,6 +25,8 @@
 #ifndef _UAPI_HYPERV_H
 #define _UAPI_HYPERV_H
 
+#include <linux/uuid.h>
+
 /*
  * Framework version for util services.
  */
@@ -93,6 +95,50 @@ struct hv_vss_msg {
 	};
 } __attribute__((packed));
 
+/*
+ * Implementation of a host to guest copy facility.
+ */
+
+#define FCOPY_VERSION_0 0
+#define FCOPY_CURRENT_VERSION FCOPY_VERSION_0
+#define W_MAX_PATH 260
+
+enum hv_fcopy_op {
+	START_FILE_COPY = 0,
+	WRITE_TO_FILE,
+	COMPLETE_FCOPY,
+	CANCEL_FCOPY,
+};
+
+struct hv_fcopy_hdr {
+	__u32 operation;
+	uuid_le service_id0; /* currently unused */
+	uuid_le service_id1; /* currently unused */
+} __attribute__((packed));
+
+#define OVER_WRITE	0x1
+#define CREATE_PATH	0x2
+
+struct hv_start_fcopy {
+	struct hv_fcopy_hdr hdr;
+	__u16 file_name[W_MAX_PATH];
+	__u16 path_name[W_MAX_PATH];
+	__u32 copy_flags;
+	__u64 file_size;
+} __attribute__((packed));
+
+/*
+ * The file is chunked into fragments.
+ */
+#define DATA_FRAGMENT	(6 * 1024)
+
+struct hv_do_fcopy {
+	struct hv_fcopy_hdr hdr;
+	__u64	offset;
+	__u32	size;
+	__u8	data[DATA_FRAGMENT];
+};
+
 /*
  * An implementation of HyperV key value pair (KVP) functionality for Linux.
  *

tools/hv/hv_fcopy_daemon.c

+/*
+ * An implementation of host to guest copy functionality for Linux.
+ *
+ * Copyright (C) 2014, Microsoft, Inc.
+ *
+ * Author : K. Y. Srinivasan <kys@microsoft.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT.  See the GNU General Public License for more
+ * details.
+ */
+
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/poll.h>
+#include <linux/types.h>
+#include <linux/kdev_t.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <ctype.h>
+#include <errno.h>
+#include <linux/hyperv.h>
+#include <syslog.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <dirent.h>
+
+static int target_fd;
+static char target_fname[W_MAX_PATH];
+
+static int hv_start_fcopy(struct hv_start_fcopy *smsg)
+{
+	int error = HV_E_FAIL;
+	char *q, *p;
+
+	/*
+	 * If possile append a path seperator to the path.
+	 */
+	if (strlen((char *)smsg->path_name) < (W_MAX_PATH - 2))
+		strcat((char *)smsg->path_name, "/");
+
+	p = (char *)smsg->path_name;
+	snprintf(target_fname, sizeof(target_fname), "%s/%s",
+		(char *)smsg->path_name, smsg->file_name);
+
+	syslog(LOG_INFO, "Target file name: %s", target_fname);
+	/*
+	 * Check to see if the path is already in place; if not,
+	 * create if required.
+	 */
+	while ((q = strchr(p, '/')) != NULL) {
+		if (q == p) {
+			p++;
+			continue;
+		}
+		*q = '\0';
+		if (access((char *)smsg->path_name, F_OK)) {
+			if (smsg->copy_flags & CREATE_PATH) {
+				if (mkdir((char *)smsg->path_name, 0755)) {
+					syslog(LOG_ERR, "Failed to create %s",
+						(char *)smsg->path_name);
+					goto done;
+				}
+			} else {
+				syslog(LOG_ERR, "Invalid path: %s",
+					(char *)smsg->path_name);
+				goto done;
+			}
+		}
+		p = q + 1;
+		*q = '/';
+	}
+
+	if (!access(target_fname, F_OK)) {
+		syslog(LOG_INFO, "File: %s exists", target_fname);
+		if (!smsg->copy_flags & OVER_WRITE)
+			goto done;
+	}
+
+	target_fd = open(target_fname, O_RDWR | O_CREAT | O_CLOEXEC, 0744);
+	if (target_fd == -1) {
+		syslog(LOG_INFO, "Open Failed: %s", strerror(errno));
+		goto done;
+	}
+
+	error = 0;
+done:
+	return error;
+}
+
+static int hv_copy_data(struct hv_do_fcopy *cpmsg)
+{
+	ssize_t bytes_written;
+
+	bytes_written = pwrite(target_fd, cpmsg->data, cpmsg->size,
+				cpmsg->offset);
+
+	if (bytes_written != cpmsg->size)
+		return HV_E_FAIL;
+
+	return 0;
+}
+
+static int hv_copy_finished(void)
+{
+	close(target_fd);
+	return 0;
+}
+static int hv_copy_cancel(void)
+{
+	close(target_fd);
+	unlink(target_fname);
+	return 0;
+
+}
+
+int main(void)
+{
+	int fd, fcopy_fd, len;
+	int error;
+	int version = FCOPY_CURRENT_VERSION;
+	char *buffer[4096 * 2];
+	struct hv_fcopy_hdr *in_msg;
+
+	if (daemon(1, 0)) {
+		syslog(LOG_ERR, "daemon() failed; error: %s", strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	openlog("HV_FCOPY", 0, LOG_USER);
+	syslog(LOG_INFO, "HV_FCOPY starting; pid is:%d", getpid());
+
+	fcopy_fd = open("/dev/vmbus/hv_fcopy", O_RDWR);
+
+	if (fcopy_fd < 0) {
+		syslog(LOG_ERR, "open /dev/vmbus/hv_fcopy failed; error: %d %s",
+			errno, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	/*
+	 * Register with the kernel.
+	 */
+	if ((write(fcopy_fd, &version, sizeof(int))) != sizeof(int)) {
+		syslog(LOG_ERR, "Registration failed: %s", strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	while (1) {
+		/*
+		 * In this loop we process fcopy messages after the
+		 * handshake is complete.
+		 */
+		len = pread(fcopy_fd, buffer, (4096 * 2), 0);
+		if (len < 0) {
+			syslog(LOG_ERR, "pread failed: %s", strerror(errno));
+			exit(EXIT_FAILURE);
+		}
+		in_msg = (struct hv_fcopy_hdr *)buffer;
+
+		switch (in_msg->operation) {
+		case START_FILE_COPY:
+			error = hv_start_fcopy((struct hv_start_fcopy *)in_msg);
+			break;
+		case WRITE_TO_FILE:
+			error = hv_copy_data((struct hv_do_fcopy *)in_msg);
+			break;
+		case COMPLETE_FCOPY:
+			error = hv_copy_finished();
+			break;
+		case CANCEL_FCOPY:
+			error = hv_copy_cancel();
+			break;
+
+		default:
+			syslog(LOG_ERR, "Unknown operation: %d",
+				in_msg->operation);
+
+		}
+
+		if (pwrite(fcopy_fd, &error, sizeof(int), 0) != sizeof(int)) {
+			syslog(LOG_ERR, "pwrite failed: %s", strerror(errno));
+			exit(EXIT_FAILURE);
+		}
+	}
+}