linux/tools/hv/hv_fcopy_daemon.c
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   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 <string.h>
  25#include <errno.h>
  26#include <linux/hyperv.h>
  27#include <linux/limits.h>
  28#include <syslog.h>
  29#include <sys/stat.h>
  30#include <fcntl.h>
  31#include <getopt.h>
  32
  33static int target_fd;
  34static char target_fname[PATH_MAX];
  35static unsigned long long filesize;
  36
  37static int hv_start_fcopy(struct hv_start_fcopy *smsg)
  38{
  39        int error = HV_E_FAIL;
  40        char *q, *p;
  41
  42        filesize = 0;
  43        p = (char *)smsg->path_name;
  44        snprintf(target_fname, sizeof(target_fname), "%s/%s",
  45                 (char *)smsg->path_name, (char *)smsg->file_name);
  46
  47        syslog(LOG_INFO, "Target file name: %s", target_fname);
  48        /*
  49         * Check to see if the path is already in place; if not,
  50         * create if required.
  51         */
  52        while ((q = strchr(p, '/')) != NULL) {
  53                if (q == p) {
  54                        p++;
  55                        continue;
  56                }
  57                *q = '\0';
  58                if (access((char *)smsg->path_name, F_OK)) {
  59                        if (smsg->copy_flags & CREATE_PATH) {
  60                                if (mkdir((char *)smsg->path_name, 0755)) {
  61                                        syslog(LOG_ERR, "Failed to create %s",
  62                                                (char *)smsg->path_name);
  63                                        goto done;
  64                                }
  65                        } else {
  66                                syslog(LOG_ERR, "Invalid path: %s",
  67                                        (char *)smsg->path_name);
  68                                goto done;
  69                        }
  70                }
  71                p = q + 1;
  72                *q = '/';
  73        }
  74
  75        if (!access(target_fname, F_OK)) {
  76                syslog(LOG_INFO, "File: %s exists", target_fname);
  77                if (!(smsg->copy_flags & OVER_WRITE)) {
  78                        error = HV_ERROR_ALREADY_EXISTS;
  79                        goto done;
  80                }
  81        }
  82
  83        target_fd = open(target_fname,
  84                         O_RDWR | O_CREAT | O_TRUNC | O_CLOEXEC, 0744);
  85        if (target_fd == -1) {
  86                syslog(LOG_INFO, "Open Failed: %s", strerror(errno));
  87                goto done;
  88        }
  89
  90        error = 0;
  91done:
  92        return error;
  93}
  94
  95static int hv_copy_data(struct hv_do_fcopy *cpmsg)
  96{
  97        ssize_t bytes_written;
  98        int ret = 0;
  99
 100        bytes_written = pwrite(target_fd, cpmsg->data, cpmsg->size,
 101                                cpmsg->offset);
 102
 103        filesize += cpmsg->size;
 104        if (bytes_written != cpmsg->size) {
 105                switch (errno) {
 106                case ENOSPC:
 107                        ret = HV_ERROR_DISK_FULL;
 108                        break;
 109                default:
 110                        ret = HV_E_FAIL;
 111                        break;
 112                }
 113                syslog(LOG_ERR, "pwrite failed to write %llu bytes: %ld (%s)",
 114                       filesize, (long)bytes_written, strerror(errno));
 115        }
 116
 117        return ret;
 118}
 119
 120static int hv_copy_finished(void)
 121{
 122        close(target_fd);
 123        return 0;
 124}
 125static int hv_copy_cancel(void)
 126{
 127        close(target_fd);
 128        unlink(target_fname);
 129        return 0;
 130
 131}
 132
 133void print_usage(char *argv[])
 134{
 135        fprintf(stderr, "Usage: %s [options]\n"
 136                "Options are:\n"
 137                "  -n, --no-daemon        stay in foreground, don't daemonize\n"
 138                "  -h, --help             print this help\n", argv[0]);
 139}
 140
 141int main(int argc, char *argv[])
 142{
 143        int fcopy_fd;
 144        int error;
 145        int daemonize = 1, long_index = 0, opt;
 146        int version = FCOPY_CURRENT_VERSION;
 147        union {
 148                struct hv_fcopy_hdr hdr;
 149                struct hv_start_fcopy start;
 150                struct hv_do_fcopy copy;
 151                __u32 kernel_modver;
 152        } buffer = { };
 153        int in_handshake = 1;
 154
 155        static struct option long_options[] = {
 156                {"help",        no_argument,       0,  'h' },
 157                {"no-daemon",   no_argument,       0,  'n' },
 158                {0,             0,                 0,  0   }
 159        };
 160
 161        while ((opt = getopt_long(argc, argv, "hn", long_options,
 162                                  &long_index)) != -1) {
 163                switch (opt) {
 164                case 'n':
 165                        daemonize = 0;
 166                        break;
 167                case 'h':
 168                default:
 169                        print_usage(argv);
 170                        exit(EXIT_FAILURE);
 171                }
 172        }
 173
 174        if (daemonize && daemon(1, 0)) {
 175                syslog(LOG_ERR, "daemon() failed; error: %s", strerror(errno));
 176                exit(EXIT_FAILURE);
 177        }
 178
 179        openlog("HV_FCOPY", 0, LOG_USER);
 180        syslog(LOG_INFO, "starting; pid is:%d", getpid());
 181
 182        fcopy_fd = open("/dev/vmbus/hv_fcopy", O_RDWR);
 183
 184        if (fcopy_fd < 0) {
 185                syslog(LOG_ERR, "open /dev/vmbus/hv_fcopy failed; error: %d %s",
 186                        errno, strerror(errno));
 187                exit(EXIT_FAILURE);
 188        }
 189
 190        /*
 191         * Register with the kernel.
 192         */
 193        if ((write(fcopy_fd, &version, sizeof(int))) != sizeof(int)) {
 194                syslog(LOG_ERR, "Registration failed: %s", strerror(errno));
 195                exit(EXIT_FAILURE);
 196        }
 197
 198        while (1) {
 199                /*
 200                 * In this loop we process fcopy messages after the
 201                 * handshake is complete.
 202                 */
 203                ssize_t len;
 204
 205                len = pread(fcopy_fd, &buffer, sizeof(buffer), 0);
 206                if (len < 0) {
 207                        syslog(LOG_ERR, "pread failed: %s", strerror(errno));
 208                        exit(EXIT_FAILURE);
 209                }
 210
 211                if (in_handshake) {
 212                        if (len != sizeof(buffer.kernel_modver)) {
 213                                syslog(LOG_ERR, "invalid version negotiation");
 214                                exit(EXIT_FAILURE);
 215                        }
 216                        in_handshake = 0;
 217                        syslog(LOG_INFO, "kernel module version: %u",
 218                               buffer.kernel_modver);
 219                        continue;
 220                }
 221
 222                switch (buffer.hdr.operation) {
 223                case START_FILE_COPY:
 224                        error = hv_start_fcopy(&buffer.start);
 225                        break;
 226                case WRITE_TO_FILE:
 227                        error = hv_copy_data(&buffer.copy);
 228                        break;
 229                case COMPLETE_FCOPY:
 230                        error = hv_copy_finished();
 231                        break;
 232                case CANCEL_FCOPY:
 233                        error = hv_copy_cancel();
 234                        break;
 235
 236                default:
 237                        syslog(LOG_ERR, "Unknown operation: %d",
 238                                buffer.hdr.operation);
 239
 240                }
 241
 242                if (pwrite(fcopy_fd, &error, sizeof(int), 0) != sizeof(int)) {
 243                        syslog(LOG_ERR, "pwrite failed: %s", strerror(errno));
 244                        exit(EXIT_FAILURE);
 245                }
 246        }
 247}
 248