1/*
2 * An implementation of host to guest copy functionality for Linux.
3 *
4 * Copyright (C) 2014, Microsoft, Inc.
5 *
6 * Author : K. Y. Srinivasan <kys@microsoft.com>
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 as published
10 * by the Free Software Foundation.
11 *
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
15 * NON INFRINGEMENT.  See the GNU General Public License for more
16 * details.
17 */
18
19
20#include <sys/types.h>
21#include <sys/socket.h>
22#include <sys/poll.h>
23#include <linux/types.h>
24#include <linux/kdev_t.h>
25#include <stdio.h>
26#include <stdlib.h>
27#include <unistd.h>
28#include <string.h>
29#include <ctype.h>
30#include <errno.h>
31#include <linux/hyperv.h>
32#include <syslog.h>
33#include <sys/stat.h>
34#include <fcntl.h>
35#include <dirent.h>
36#include <getopt.h>
37
38static int target_fd;
39static char target_fname[W_MAX_PATH];
40
41static int hv_start_fcopy(struct hv_start_fcopy *smsg)
42{
43	int error = HV_E_FAIL;
44	char *q, *p;
45
46	p = (char *)smsg->path_name;
47	snprintf(target_fname, sizeof(target_fname), "%s/%s",
48		 (char *)smsg->path_name, (char *)smsg->file_name);
49
50	syslog(LOG_INFO, "Target file name: %s", target_fname);
51	/*
52	 * Check to see if the path is already in place; if not,
53	 * create if required.
54	 */
55	while ((q = strchr(p, '/')) != NULL) {
56		if (q == p) {
57			p++;
58			continue;
59		}
60		*q = '\0';
61		if (access((char *)smsg->path_name, F_OK)) {
62			if (smsg->copy_flags & CREATE_PATH) {
63				if (mkdir((char *)smsg->path_name, 0755)) {
64					syslog(LOG_ERR, "Failed to create %s",
65						(char *)smsg->path_name);
66					goto done;
67				}
68			} else {
69				syslog(LOG_ERR, "Invalid path: %s",
70					(char *)smsg->path_name);
71				goto done;
72			}
73		}
74		p = q + 1;
75		*q = '/';
76	}
77
78	if (!access(target_fname, F_OK)) {
79		syslog(LOG_INFO, "File: %s exists", target_fname);
80		if (!(smsg->copy_flags & OVER_WRITE)) {
81			error = HV_ERROR_ALREADY_EXISTS;
82			goto done;
83		}
84	}
85
86	target_fd = open(target_fname,
87			 O_RDWR | O_CREAT | O_TRUNC | O_CLOEXEC, 0744);
88	if (target_fd == -1) {
89		syslog(LOG_INFO, "Open Failed: %s", strerror(errno));
90		goto done;
91	}
92
93	error = 0;
94done:
95	return error;
96}
97
98static int hv_copy_data(struct hv_do_fcopy *cpmsg)
99{
100	ssize_t bytes_written;
101
102	bytes_written = pwrite(target_fd, cpmsg->data, cpmsg->size,
103				cpmsg->offset);
104
105	if (bytes_written != cpmsg->size)
106		return HV_E_FAIL;
107
108	return 0;
109}
110
111static int hv_copy_finished(void)
112{
113	close(target_fd);
114	return 0;
115}
116static int hv_copy_cancel(void)
117{
118	close(target_fd);
119	unlink(target_fname);
120	return 0;
121
122}
123
124void print_usage(char *argv[])
125{
126	fprintf(stderr, "Usage: %s [options]\n"
127		"Options are:\n"
128		"  -n, --no-daemon        stay in foreground, don't daemonize\n"
129		"  -h, --help             print this help\n", argv[0]);
130}
131
132int main(int argc, char *argv[])
133{
134	int fcopy_fd, len;
135	int error;
136	int daemonize = 1, long_index = 0, opt;
137	int version = FCOPY_CURRENT_VERSION;
138	char *buffer[4096 * 2];
139	struct hv_fcopy_hdr *in_msg;
140
141	static struct option long_options[] = {
142		{"help",	no_argument,	   0,  'h' },
143		{"no-daemon",	no_argument,	   0,  'n' },
144		{0,		0,		   0,  0   }
145	};
146
147	while ((opt = getopt_long(argc, argv, "hn", long_options,
148				  &long_index)) != -1) {
149		switch (opt) {
150		case 'n':
151			daemonize = 0;
152			break;
153		case 'h':
154		default:
155			print_usage(argv);
156			exit(EXIT_FAILURE);
157		}
158	}
159
160	if (daemonize && daemon(1, 0)) {
161		syslog(LOG_ERR, "daemon() failed; error: %s", strerror(errno));
162		exit(EXIT_FAILURE);
163	}
164
165	openlog("HV_FCOPY", 0, LOG_USER);
166	syslog(LOG_INFO, "HV_FCOPY starting; pid is:%d", getpid());
167
168	fcopy_fd = open("/dev/vmbus/hv_fcopy", O_RDWR);
169
170	if (fcopy_fd < 0) {
171		syslog(LOG_ERR, "open /dev/vmbus/hv_fcopy failed; error: %d %s",
172			errno, strerror(errno));
173		exit(EXIT_FAILURE);
174	}
175
176	/*
177	 * Register with the kernel.
178	 */
179	if ((write(fcopy_fd, &version, sizeof(int))) != sizeof(int)) {
180		syslog(LOG_ERR, "Registration failed: %s", strerror(errno));
181		exit(EXIT_FAILURE);
182	}
183
184	while (1) {
185		/*
186		 * In this loop we process fcopy messages after the
187		 * handshake is complete.
188		 */
189		len = pread(fcopy_fd, buffer, (4096 * 2), 0);
190		if (len < 0) {
191			syslog(LOG_ERR, "pread failed: %s", strerror(errno));
192			exit(EXIT_FAILURE);
193		}
194		in_msg = (struct hv_fcopy_hdr *)buffer;
195
196		switch (in_msg->operation) {
197		case START_FILE_COPY:
198			error = hv_start_fcopy((struct hv_start_fcopy *)in_msg);
199			break;
200		case WRITE_TO_FILE:
201			error = hv_copy_data((struct hv_do_fcopy *)in_msg);
202			break;
203		case COMPLETE_FCOPY:
204			error = hv_copy_finished();
205			break;
206		case CANCEL_FCOPY:
207			error = hv_copy_cancel();
208			break;
209
210		default:
211			syslog(LOG_ERR, "Unknown operation: %d",
212				in_msg->operation);
213
214		}
215
216		if (pwrite(fcopy_fd, &error, sizeof(int), 0) != sizeof(int)) {
217			syslog(LOG_ERR, "pwrite failed: %s", strerror(errno));
218			exit(EXIT_FAILURE);
219		}
220	}
221}
222