tools/hv/hv_fcopy_daemon.c

   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 <stdio.h>
  22 #include <stdlib.h>
  23 #include <unistd.h>
  24 #include <errno.h>
  25 #include <linux/hyperv.h>
  26 #include <syslog.h>
  27 #include <sys/stat.h>
  28 #include <fcntl.h>
  29 #include <getopt.h>
  30
  31 static int target_fd;
  32 static char target_fname[W_MAX_PATH];
  33 static unsigned long long filesize;
  34
  35 static int hv_start_fcopy(struct hv_start_fcopy *smsg)
  36 {
  37         int error = HV_E_FAIL;
  38         char *q, *p;
  39
  40         filesize = 0;
  41         p = (char *)smsg->path_name;
  42         snprintf(target_fname, sizeof(target_fname), "%s/%s",
  43                  (char *)smsg->path_name, (char *)smsg->file_name);
  44
  45         syslog(LOG_INFO, "Target file name: %s", target_fname);
  46         /*
  47          * Check to see if the path is already in place; if not,
  48          * create if required.
  49          */
  50         while ((q = strchr(p, '/')) != NULL) {
  51                 if (q == p) {
  52                         p++;
  53                         continue;
  54                 }
  55                 *q = '\0';
  56                 if (access((char *)smsg->path_name, F_OK)) {
  57                         if (smsg->copy_flags & CREATE_PATH) {
  58                                 if (mkdir((char *)smsg->path_name, 0755)) {
  59                                         syslog(LOG_ERR, "Failed to create %s",
  60                                                 (char *)smsg->path_name);
  61                                         goto done;
  62                                 }
  63                         } else {
  64                                 syslog(LOG_ERR, "Invalid path: %s",
  65                                         (char *)smsg->path_name);
  66                                 goto done;
  67                         }
  68                 }
  69                 p = q + 1;
  70                 *q = '/';
  71         }
  72
  73         if (!access(target_fname, F_OK)) {
  74                 syslog(LOG_INFO, "File: %s exists", target_fname);
  75                 if (!(smsg->copy_flags & OVER_WRITE)) {
  76                         error = HV_ERROR_ALREADY_EXISTS;
  77                         goto done;
  78                 }
  79         }
  80
  81         target_fd = open(target_fname,
  82                          O_RDWR | O_CREAT | O_TRUNC | O_CLOEXEC, 0744);
  83         if (target_fd == -1) {
  84                 syslog(LOG_INFO, "Open Failed: %s", strerror(errno));
  85                 goto done;
  86         }
  87
  88         error = 0;
  89 done:
  90         return error;
  91 }
  92
  93 static int hv_copy_data(struct hv_do_fcopy *cpmsg)
  94 {
  95         ssize_t bytes_written;
  96         int ret = 0;
  97
  98         bytes_written = pwrite(target_fd, cpmsg->data, cpmsg->size,
  99                                 cpmsg->offset);
 100
 101         filesize += cpmsg->size;
 102         if (bytes_written != cpmsg->size) {
 103                 switch (errno) {
 104                 case ENOSPC:
 105                         ret = HV_ERROR_DISK_FULL;
 106                         break;
 107                 default:
 108                         ret = HV_E_FAIL;
 109                         break;
 110                 }
 111                 syslog(LOG_ERR, "pwrite failed to write %llu bytes: %ld (%s)",
 112                        filesize, (long)bytes_written, strerror(errno));
 113         }
 114
 115         return ret;
 116 }
 117
 118 static int hv_copy_finished(void)
 119 {
 120         close(target_fd);
 121         return 0;
 122 }
 123 static int hv_copy_cancel(void)
 124 {
 125         close(target_fd);
 126         unlink(target_fname);
 127         return 0;
 128
 129 }
 130
 131 void print_usage(char *argv[])
 132 {
 133         fprintf(stderr, "Usage: %s [options]\n"
 134                 "Options are:\n"
 135                 "  -n, --no-daemon        stay in foreground, don't daemonize\n"
 136                 "  -h, --help             print this help\n", argv[0]);
 137 }
 138
 139 int main(int argc, char *argv[])
 140 {
 141         int fcopy_fd;
 142         int error;
 143         int daemonize = 1, long_index = 0, opt;
 144         int version = FCOPY_CURRENT_VERSION;
 145         union {
 146                 struct hv_fcopy_hdr hdr;
 147                 struct hv_start_fcopy start;
 148                 struct hv_do_fcopy copy;
 149                 __u32 kernel_modver;
 150         } buffer = { };
 151         int in_handshake = 1;
 152
 153         static struct option long_options[] = {
 154                 {"help",        no_argument,       0,  'h' },
 155                 {"no-daemon",   no_argument,       0,  'n' },
 156                 {0,             0,                 0,  0   }
 157         };
 158
 159         while ((opt = getopt_long(argc, argv, "hn", long_options,
 160                                   &long_index)) != -1) {
 161                 switch (opt) {
 162                 case 'n':
 163                         daemonize = 0;
 164                         break;
 165                 case 'h':
 166                 default:
 167                         print_usage(argv);
 168                         exit(EXIT_FAILURE);
 169                 }
 170         }
 171
 172         if (daemonize && daemon(1, 0)) {
 173                 syslog(LOG_ERR, "daemon() failed; error: %s", strerror(errno));
 174                 exit(EXIT_FAILURE);
 175         }
 176
 177         openlog("HV_FCOPY", 0, LOG_USER);
 178         syslog(LOG_INFO, "starting; pid is:%d", getpid());
 179
 180         fcopy_fd = open("/dev/vmbus/hv_fcopy", O_RDWR);
 181
 182         if (fcopy_fd < 0) {
 183                 syslog(LOG_ERR, "open /dev/vmbus/hv_fcopy failed; error: %d %s",
 184                         errno, strerror(errno));
 185                 exit(EXIT_FAILURE);
 186         }
 187
 188         /*
 189          * Register with the kernel.
 190          */
 191         if ((write(fcopy_fd, &version, sizeof(int))) != sizeof(int)) {
 192                 syslog(LOG_ERR, "Registration failed: %s", strerror(errno));
 193                 exit(EXIT_FAILURE);
 194         }
 195
 196         while (1) {
 197                 /*
 198                  * In this loop we process fcopy messages after the
 199                  * handshake is complete.
 200                  */
 201                 ssize_t len;
 202
 203                 len = pread(fcopy_fd, &buffer, sizeof(buffer), 0);
 204                 if (len < 0) {
 205                         syslog(LOG_ERR, "pread failed: %s", strerror(errno));
 206                         exit(EXIT_FAILURE);
 207                 }
 208
 209                 if (in_handshake) {
 210                         if (len != sizeof(buffer.kernel_modver)) {
 211                                 syslog(LOG_ERR, "invalid version negotiation");
 212                                 exit(EXIT_FAILURE);
 213                         }
 214                         in_handshake = 0;
 215                         syslog(LOG_INFO, "kernel module version: %u",
 216                                buffer.kernel_modver);
 217                         continue;
 218                 }
 219
 220                 switch (buffer.hdr.operation) {
 221                 case START_FILE_COPY:
 222                         error = hv_start_fcopy(&buffer.start);
 223                         break;
 224                 case WRITE_TO_FILE:
 225                         error = hv_copy_data(&buffer.copy);
 226                         break;
 227                 case COMPLETE_FCOPY:
 228                         error = hv_copy_finished();
 229                         break;
 230                 case CANCEL_FCOPY:
 231                         error = hv_copy_cancel();
 232                         break;
 233
 234                 default:
 235                         syslog(LOG_ERR, "Unknown operation: %d",
 236                                 buffer.hdr.operation);
 237
 238                 }
 239
 240                 if (pwrite(fcopy_fd, &error, sizeof(int), 0) != sizeof(int)) {
 241                         syslog(LOG_ERR, "pwrite failed: %s", strerror(errno));
 242                         exit(EXIT_FAILURE);
 243                 }
 244         }
 245 }