xref: /openbmc/linux/tools/hv/hv_fcopy_daemon.c (revision 8684014d)
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 
38 static int target_fd;
39 static char target_fname[W_MAX_PATH];
40 
41 static int hv_start_fcopy(struct hv_start_fcopy *smsg)
42 {
43 	int error = HV_E_FAIL;
44 	char *q, *p;
45 
46 	/*
47 	 * If possile append a path seperator to the path.
48 	 */
49 	if (strlen((char *)smsg->path_name) < (W_MAX_PATH - 2))
50 		strcat((char *)smsg->path_name, "/");
51 
52 	p = (char *)smsg->path_name;
53 	snprintf(target_fname, sizeof(target_fname), "%s/%s",
54 		(char *)smsg->path_name, smsg->file_name);
55 
56 	syslog(LOG_INFO, "Target file name: %s", target_fname);
57 	/*
58 	 * Check to see if the path is already in place; if not,
59 	 * create if required.
60 	 */
61 	while ((q = strchr(p, '/')) != NULL) {
62 		if (q == p) {
63 			p++;
64 			continue;
65 		}
66 		*q = '\0';
67 		if (access((char *)smsg->path_name, F_OK)) {
68 			if (smsg->copy_flags & CREATE_PATH) {
69 				if (mkdir((char *)smsg->path_name, 0755)) {
70 					syslog(LOG_ERR, "Failed to create %s",
71 						(char *)smsg->path_name);
72 					goto done;
73 				}
74 			} else {
75 				syslog(LOG_ERR, "Invalid path: %s",
76 					(char *)smsg->path_name);
77 				goto done;
78 			}
79 		}
80 		p = q + 1;
81 		*q = '/';
82 	}
83 
84 	if (!access(target_fname, F_OK)) {
85 		syslog(LOG_INFO, "File: %s exists", target_fname);
86 		if (!(smsg->copy_flags & OVER_WRITE)) {
87 			error = HV_ERROR_ALREADY_EXISTS;
88 			goto done;
89 		}
90 	}
91 
92 	target_fd = open(target_fname,
93 			 O_RDWR | O_CREAT | O_TRUNC | O_CLOEXEC, 0744);
94 	if (target_fd == -1) {
95 		syslog(LOG_INFO, "Open Failed: %s", strerror(errno));
96 		goto done;
97 	}
98 
99 	error = 0;
100 done:
101 	return error;
102 }
103 
104 static int hv_copy_data(struct hv_do_fcopy *cpmsg)
105 {
106 	ssize_t bytes_written;
107 
108 	bytes_written = pwrite(target_fd, cpmsg->data, cpmsg->size,
109 				cpmsg->offset);
110 
111 	if (bytes_written != cpmsg->size)
112 		return HV_E_FAIL;
113 
114 	return 0;
115 }
116 
117 static int hv_copy_finished(void)
118 {
119 	close(target_fd);
120 	return 0;
121 }
122 static int hv_copy_cancel(void)
123 {
124 	close(target_fd);
125 	unlink(target_fname);
126 	return 0;
127 
128 }
129 
130 void print_usage(char *argv[])
131 {
132 	fprintf(stderr, "Usage: %s [options]\n"
133 		"Options are:\n"
134 		"  -n, --no-daemon        stay in foreground, don't daemonize\n"
135 		"  -h, --help             print this help\n", argv[0]);
136 }
137 
138 int main(int argc, char *argv[])
139 {
140 	int fd, fcopy_fd, len;
141 	int error;
142 	int daemonize = 1, long_index = 0, opt;
143 	int version = FCOPY_CURRENT_VERSION;
144 	char *buffer[4096 * 2];
145 	struct hv_fcopy_hdr *in_msg;
146 
147 	static struct option long_options[] = {
148 		{"help",	no_argument,	   0,  'h' },
149 		{"no-daemon",	no_argument,	   0,  'n' },
150 		{0,		0,		   0,  0   }
151 	};
152 
153 	while ((opt = getopt_long(argc, argv, "hn", long_options,
154 				  &long_index)) != -1) {
155 		switch (opt) {
156 		case 'n':
157 			daemonize = 0;
158 			break;
159 		case 'h':
160 		default:
161 			print_usage(argv);
162 			exit(EXIT_FAILURE);
163 		}
164 	}
165 
166 	if (daemonize && daemon(1, 0)) {
167 		syslog(LOG_ERR, "daemon() failed; error: %s", strerror(errno));
168 		exit(EXIT_FAILURE);
169 	}
170 
171 	openlog("HV_FCOPY", 0, LOG_USER);
172 	syslog(LOG_INFO, "HV_FCOPY starting; pid is:%d", getpid());
173 
174 	fcopy_fd = open("/dev/vmbus/hv_fcopy", O_RDWR);
175 
176 	if (fcopy_fd < 0) {
177 		syslog(LOG_ERR, "open /dev/vmbus/hv_fcopy failed; error: %d %s",
178 			errno, strerror(errno));
179 		exit(EXIT_FAILURE);
180 	}
181 
182 	/*
183 	 * Register with the kernel.
184 	 */
185 	if ((write(fcopy_fd, &version, sizeof(int))) != sizeof(int)) {
186 		syslog(LOG_ERR, "Registration failed: %s", strerror(errno));
187 		exit(EXIT_FAILURE);
188 	}
189 
190 	while (1) {
191 		/*
192 		 * In this loop we process fcopy messages after the
193 		 * handshake is complete.
194 		 */
195 		len = pread(fcopy_fd, buffer, (4096 * 2), 0);
196 		if (len < 0) {
197 			syslog(LOG_ERR, "pread failed: %s", strerror(errno));
198 			exit(EXIT_FAILURE);
199 		}
200 		in_msg = (struct hv_fcopy_hdr *)buffer;
201 
202 		switch (in_msg->operation) {
203 		case START_FILE_COPY:
204 			error = hv_start_fcopy((struct hv_start_fcopy *)in_msg);
205 			break;
206 		case WRITE_TO_FILE:
207 			error = hv_copy_data((struct hv_do_fcopy *)in_msg);
208 			break;
209 		case COMPLETE_FCOPY:
210 			error = hv_copy_finished();
211 			break;
212 		case CANCEL_FCOPY:
213 			error = hv_copy_cancel();
214 			break;
215 
216 		default:
217 			syslog(LOG_ERR, "Unknown operation: %d",
218 				in_msg->operation);
219 
220 		}
221 
222 		if (pwrite(fcopy_fd, &error, sizeof(int), 0) != sizeof(int)) {
223 			syslog(LOG_ERR, "pwrite failed: %s", strerror(errno));
224 			exit(EXIT_FAILURE);
225 		}
226 	}
227 }
228