1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * An implementation of host to guest copy functionality for Linux.
4 *
5 * Copyright (C) 2014, Microsoft, Inc.
6 *
7 * Author : K. Y. Srinivasan <kys@microsoft.com>
8 */
9
10
11 #include <sys/types.h>
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include <unistd.h>
15 #include <string.h>
16 #include <errno.h>
17 #include <linux/hyperv.h>
18 #include <linux/limits.h>
19 #include <syslog.h>
20 #include <sys/stat.h>
21 #include <fcntl.h>
22 #include <getopt.h>
23
24 static int target_fd;
25 static char target_fname[PATH_MAX];
26 static unsigned long long filesize;
27
hv_start_fcopy(struct hv_start_fcopy * smsg)28 static int hv_start_fcopy(struct hv_start_fcopy *smsg)
29 {
30 int error = HV_E_FAIL;
31 char *q, *p;
32
33 filesize = 0;
34 p = (char *)smsg->path_name;
35 snprintf(target_fname, sizeof(target_fname), "%s/%s",
36 (char *)smsg->path_name, (char *)smsg->file_name);
37
38 syslog(LOG_INFO, "Target file name: %s", target_fname);
39 /*
40 * Check to see if the path is already in place; if not,
41 * create if required.
42 */
43 while ((q = strchr(p, '/')) != NULL) {
44 if (q == p) {
45 p++;
46 continue;
47 }
48 *q = '\0';
49 if (access((char *)smsg->path_name, F_OK)) {
50 if (smsg->copy_flags & CREATE_PATH) {
51 if (mkdir((char *)smsg->path_name, 0755)) {
52 syslog(LOG_ERR, "Failed to create %s",
53 (char *)smsg->path_name);
54 goto done;
55 }
56 } else {
57 syslog(LOG_ERR, "Invalid path: %s",
58 (char *)smsg->path_name);
59 goto done;
60 }
61 }
62 p = q + 1;
63 *q = '/';
64 }
65
66 if (!access(target_fname, F_OK)) {
67 syslog(LOG_INFO, "File: %s exists", target_fname);
68 if (!(smsg->copy_flags & OVER_WRITE)) {
69 error = HV_ERROR_ALREADY_EXISTS;
70 goto done;
71 }
72 }
73
74 target_fd = open(target_fname,
75 O_RDWR | O_CREAT | O_TRUNC | O_CLOEXEC, 0744);
76 if (target_fd == -1) {
77 syslog(LOG_INFO, "Open Failed: %s", strerror(errno));
78 goto done;
79 }
80
81 error = 0;
82 done:
83 return error;
84 }
85
hv_copy_data(struct hv_do_fcopy * cpmsg)86 static int hv_copy_data(struct hv_do_fcopy *cpmsg)
87 {
88 ssize_t bytes_written;
89 int ret = 0;
90
91 bytes_written = pwrite(target_fd, cpmsg->data, cpmsg->size,
92 cpmsg->offset);
93
94 filesize += cpmsg->size;
95 if (bytes_written != cpmsg->size) {
96 switch (errno) {
97 case ENOSPC:
98 ret = HV_ERROR_DISK_FULL;
99 break;
100 default:
101 ret = HV_E_FAIL;
102 break;
103 }
104 syslog(LOG_ERR, "pwrite failed to write %llu bytes: %ld (%s)",
105 filesize, (long)bytes_written, strerror(errno));
106 }
107
108 return ret;
109 }
110
hv_copy_finished(void)111 static int hv_copy_finished(void)
112 {
113 close(target_fd);
114 return 0;
115 }
hv_copy_cancel(void)116 static int hv_copy_cancel(void)
117 {
118 close(target_fd);
119 unlink(target_fname);
120 return 0;
121
122 }
123
print_usage(char * argv[])124 void 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
main(int argc,char * argv[])132 int main(int argc, char *argv[])
133 {
134 int fcopy_fd;
135 int error;
136 int daemonize = 1, long_index = 0, opt;
137 int version = FCOPY_CURRENT_VERSION;
138 union {
139 struct hv_fcopy_hdr hdr;
140 struct hv_start_fcopy start;
141 struct hv_do_fcopy copy;
142 __u32 kernel_modver;
143 } buffer = { };
144 int in_handshake = 1;
145
146 static struct option long_options[] = {
147 {"help", no_argument, 0, 'h' },
148 {"no-daemon", no_argument, 0, 'n' },
149 {0, 0, 0, 0 }
150 };
151
152 while ((opt = getopt_long(argc, argv, "hn", long_options,
153 &long_index)) != -1) {
154 switch (opt) {
155 case 'n':
156 daemonize = 0;
157 break;
158 case 'h':
159 default:
160 print_usage(argv);
161 exit(EXIT_FAILURE);
162 }
163 }
164
165 if (daemonize && daemon(1, 0)) {
166 syslog(LOG_ERR, "daemon() failed; error: %s", strerror(errno));
167 exit(EXIT_FAILURE);
168 }
169
170 openlog("HV_FCOPY", 0, LOG_USER);
171 syslog(LOG_INFO, "starting; pid is:%d", getpid());
172
173 fcopy_fd = open("/dev/vmbus/hv_fcopy", O_RDWR);
174
175 if (fcopy_fd < 0) {
176 syslog(LOG_ERR, "open /dev/vmbus/hv_fcopy failed; error: %d %s",
177 errno, strerror(errno));
178 exit(EXIT_FAILURE);
179 }
180
181 /*
182 * Register with the kernel.
183 */
184 if ((write(fcopy_fd, &version, sizeof(int))) != sizeof(int)) {
185 syslog(LOG_ERR, "Registration failed: %s", strerror(errno));
186 exit(EXIT_FAILURE);
187 }
188
189 while (1) {
190 /*
191 * In this loop we process fcopy messages after the
192 * handshake is complete.
193 */
194 ssize_t len;
195
196 len = pread(fcopy_fd, &buffer, sizeof(buffer), 0);
197 if (len < 0) {
198 syslog(LOG_ERR, "pread failed: %s", strerror(errno));
199 exit(EXIT_FAILURE);
200 }
201
202 if (in_handshake) {
203 if (len != sizeof(buffer.kernel_modver)) {
204 syslog(LOG_ERR, "invalid version negotiation");
205 exit(EXIT_FAILURE);
206 }
207 in_handshake = 0;
208 syslog(LOG_INFO, "kernel module version: %u",
209 buffer.kernel_modver);
210 continue;
211 }
212
213 switch (buffer.hdr.operation) {
214 case START_FILE_COPY:
215 error = hv_start_fcopy(&buffer.start);
216 break;
217 case WRITE_TO_FILE:
218 error = hv_copy_data(&buffer.copy);
219 break;
220 case COMPLETE_FCOPY:
221 error = hv_copy_finished();
222 break;
223 case CANCEL_FCOPY:
224 error = hv_copy_cancel();
225 break;
226
227 default:
228 error = HV_E_FAIL;
229 syslog(LOG_ERR, "Unknown operation: %d",
230 buffer.hdr.operation);
231
232 }
233
234 if (pwrite(fcopy_fd, &error, sizeof(int), 0) != sizeof(int)) {
235 syslog(LOG_ERR, "pwrite failed: %s", strerror(errno));
236 exit(EXIT_FAILURE);
237 }
238 }
239 }
240