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 <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
  37 static int target_fd;
  38 static char target_fname[W_MAX_PATH];
  39
  40 static int hv_start_fcopy(struct hv_start_fcopy *smsg)
  41 {
  42         int error = HV_E_FAIL;
  43         char *q, *p;
  44
  45         /*
  46          * If possile append a path seperator to the path.
  47          */
  48         if (strlen((char *)smsg->path_name) < (W_MAX_PATH - 2))
  49                 strcat((char *)smsg->path_name, "/");
  50
  51         p = (char *)smsg->path_name;
  52         snprintf(target_fname, sizeof(target_fname), "%s/%s",
  53                 (char *)smsg->path_name, smsg->file_name);
  54
  55         syslog(LOG_INFO, "Target file name: %s", target_fname);
  56         /*
  57          * Check to see if the path is already in place; if not,
  58          * create if required.
  59          */
  60         while ((q = strchr(p, '/')) != NULL) {
  61                 if (q == p) {
  62                         p++;
  63                         continue;
  64                 }
  65                 *q = '\0';
  66                 if (access((char *)smsg->path_name, F_OK)) {
  67                         if (smsg->copy_flags & CREATE_PATH) {
  68                                 if (mkdir((char *)smsg->path_name, 0755)) {
  69                                         syslog(LOG_ERR, "Failed to create %s",
  70                                                 (char *)smsg->path_name);
  71                                         goto done;
  72                                 }
  73                         } else {
  74                                 syslog(LOG_ERR, "Invalid path: %s",
  75                                         (char *)smsg->path_name);
  76                                 goto done;
  77                         }
  78                 }
  79                 p = q + 1;
  80                 *q = '/';
  81         }
  82
  83         if (!access(target_fname, F_OK)) {
  84                 syslog(LOG_INFO, "File: %s exists", target_fname);
  85                 if (!(smsg->copy_flags & OVER_WRITE)) {
  86                         error = HV_ERROR_ALREADY_EXISTS;
  87                         goto done;
  88                 }
  89         }
  90
  91         target_fd = open(target_fname, O_RDWR | O_CREAT | O_CLOEXEC, 0744);
  92         if (target_fd == -1) {
  93                 syslog(LOG_INFO, "Open Failed: %s", strerror(errno));
  94                 goto done;
  95         }
  96
  97         error = 0;
  98 done:
  99         return error;
 100 }
 101
 102 static int hv_copy_data(struct hv_do_fcopy *cpmsg)
 103 {
 104         ssize_t bytes_written;
 105
 106         bytes_written = pwrite(target_fd, cpmsg->data, cpmsg->size,
 107                                 cpmsg->offset);
 108
 109         if (bytes_written != cpmsg->size)
 110                 return HV_E_FAIL;
 111
 112         return 0;
 113 }
 114
 115 static int hv_copy_finished(void)
 116 {
 117         close(target_fd);
 118         return 0;
 119 }
 120 static int hv_copy_cancel(void)
 121 {
 122         close(target_fd);
 123         unlink(target_fname);
 124         return 0;
 125
 126 }
 127
 128 int main(void)
 129 {
 130         int fd, fcopy_fd, len;
 131         int error;
 132         int version = FCOPY_CURRENT_VERSION;
 133         char *buffer[4096 * 2];
 134         struct hv_fcopy_hdr *in_msg;
 135
 136         if (daemon(1, 0)) {
 137                 syslog(LOG_ERR, "daemon() failed; error: %s", strerror(errno));
 138                 exit(EXIT_FAILURE);
 139         }
 140
 141         openlog("HV_FCOPY", 0, LOG_USER);
 142         syslog(LOG_INFO, "HV_FCOPY starting; pid is:%d", getpid());
 143
 144         fcopy_fd = open("/dev/vmbus/hv_fcopy", O_RDWR);
 145
 146         if (fcopy_fd < 0) {
 147                 syslog(LOG_ERR, "open /dev/vmbus/hv_fcopy failed; error: %d %s",
 148                         errno, strerror(errno));
 149                 exit(EXIT_FAILURE);
 150         }
 151
 152         /*
 153          * Register with the kernel.
 154          */
 155         if ((write(fcopy_fd, &version, sizeof(int))) != sizeof(int)) {
 156                 syslog(LOG_ERR, "Registration failed: %s", strerror(errno));
 157                 exit(EXIT_FAILURE);
 158         }
 159
 160         while (1) {
 161                 /*
 162                  * In this loop we process fcopy messages after the
 163                  * handshake is complete.
 164                  */
 165                 len = pread(fcopy_fd, buffer, (4096 * 2), 0);
 166                 if (len < 0) {
 167                         syslog(LOG_ERR, "pread failed: %s", strerror(errno));
 168                         exit(EXIT_FAILURE);
 169                 }
 170                 in_msg = (struct hv_fcopy_hdr *)buffer;
 171
 172                 switch (in_msg->operation) {
 173                 case START_FILE_COPY:
 174                         error = hv_start_fcopy((struct hv_start_fcopy *)in_msg);
 175                         break;
 176                 case WRITE_TO_FILE:
 177                         error = hv_copy_data((struct hv_do_fcopy *)in_msg);
 178                         break;
 179                 case COMPLETE_FCOPY:
 180                         error = hv_copy_finished();
 181                         break;
 182                 case CANCEL_FCOPY:
 183                         error = hv_copy_cancel();
 184                         break;
 185
 186                 default:
 187                         syslog(LOG_ERR, "Unknown operation: %d",
 188                                 in_msg->operation);
 189
 190                 }
 191
 192                 if (pwrite(fcopy_fd, &error, sizeof(int), 0) != sizeof(int)) {
 193                         syslog(LOG_ERR, "pwrite failed: %s", strerror(errno));
 194                         exit(EXIT_FAILURE);
 195                 }
 196         }
 197 }