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 <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 <errno.h>
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#include <linux hyperv.h="">
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#include <linux limits.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 <getopt.h>
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static int target_fd;
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static char target_fname[PATH_MAX];
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static unsigned long long filesize;
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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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	filesize = 0;
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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, (char *)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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	int ret = 0;
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	bytes_written = pwrite(target_fd, cpmsg->data, cpmsg->size,
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				cpmsg->offset);
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	filesize += cpmsg->size;
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	if (bytes_written != cpmsg->size) {
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		switch (errno) {
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		case ENOSPC:
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			ret = HV_ERROR_DISK_FULL;
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			break;
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		default:
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			ret = HV_E_FAIL;
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			break;
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		}
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		syslog(LOG_ERR, "pwrite failed to write %llu bytes: %ld (%s)",
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		       filesize, (long)bytes_written, strerror(errno));
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	}
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	return ret;
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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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void print_usage(char *argv[])
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{
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	fprintf(stderr, "Usage: %s [options]\n"
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		"Options are:\n"
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		"  -n, --no-daemon        stay in foreground, don't daemonize\n"
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		"  -h, --help             print this help\n", argv[0]);
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}
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int main(int argc, char *argv[])
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{
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	int fcopy_fd;
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	int error;
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	int daemonize = 1, long_index = 0, opt;
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	int version = FCOPY_CURRENT_VERSION;
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	union {
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		struct hv_fcopy_hdr hdr;
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		struct hv_start_fcopy start;
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		struct hv_do_fcopy copy;
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		__u32 kernel_modver;
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	} buffer = { };
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	int in_handshake = 1;
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	static struct option long_options[] = {
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		{"help",	no_argument,	   0,  'h' },
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		{"no-daemon",	no_argument,	   0,  'n' },
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		{0,		0,		   0,  0   }
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	};
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	while ((opt = getopt_long(argc, argv, "hn", long_options,
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				  &long_index)) != -1) {
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		switch (opt) {
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		case 'n':
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			daemonize = 0;
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			break;
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		case 'h':
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		default:
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			print_usage(argv);
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			exit(EXIT_FAILURE);
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		}
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	}
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	if (daemonize && 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, "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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		ssize_t len;
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		len = pread(fcopy_fd, &buffer, sizeof(buffer), 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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		if (in_handshake) {
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			if (len != sizeof(buffer.kernel_modver)) {
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				syslog(LOG_ERR, "invalid version negotiation");
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				exit(EXIT_FAILURE);
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			}
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			in_handshake = 0;
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			syslog(LOG_INFO, "kernel module version: %u",
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			       buffer.kernel_modver);
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			continue;
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		}
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		switch (buffer.hdr.operation) {
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		case START_FILE_COPY:
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			error = hv_start_fcopy(&buffer.start);
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			break;
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		case WRITE_TO_FILE:
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			error = hv_copy_data(&buffer.copy);
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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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				buffer.hdr.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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}