Blame SOURCES/hv_fcopy_daemon.c

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