libguestfs/p2v/conversion.c

/* virt-p2v
 * Copyright (C) 2009-2017 Red Hat Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

/**
 * This file manages the p2v conversion.
 *
 * The conversion is actually done by L<virt-v2v(1)> running on the
 * remote conversion server.  This file manages running the remote
 * command and provides callbacks for displaying the output.
 *
 * When virt-p2v operates in GUI mode, this code runs in a separate
 * thread.  When virt-p2v operates in kernel mode, this runs
 * synchronously in the main thread.
 */

#include <config.h>

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <fcntl.h>
#include <inttypes.h>
#include <unistd.h>
#include <time.h>
#include <errno.h>
#include <error.h>
#include <locale.h>
#include <libintl.h>
#include <netdb.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>

#include <pthread.h>

#include <glib.h>

#include <libxml/xmlwriter.h>

#include "ignore-value.h"
#include "getprogname.h"

#include "miniexpect.h"
#include "p2v.h"

#ifndef HAVE_XMLBUFFERDETACH
/* Added in libxml2 2.8.0.  This is mostly a copy of the function from
 * upstream libxml2, which is under a more permissive license.
 */
static xmlChar *
xmlBufferDetach (xmlBufferPtr buf)
{
  xmlChar *ret;

  if (buf == NULL)
    return NULL;
  if (buf->alloc == XML_BUFFER_ALLOC_IMMUTABLE)
    return NULL;

  ret = buf->content;
  buf->content = NULL;
  buf->size = 0;
  buf->use = 0;

  return ret;
}
#endif

/* How long to wait for qemu-nbd to start (seconds). */
#define WAIT_QEMU_NBD_TIMEOUT 10

/* Data per NBD connection / physical disk. */
struct data_conn {
  mexp_h *h;                /* miniexpect handle to ssh */
  pid_t nbd_pid;            /* qemu pid */
  int nbd_local_port;       /* local NBD port on physical machine */
  int nbd_remote_port;      /* remote NBD port on conversion server */
};

static pid_t start_qemu_nbd (int nbd_local_port, const char *device);
static int wait_qemu_nbd (int nbd_local_port, int timeout_seconds);
static void cleanup_data_conns (struct data_conn *data_conns, size_t nr);
static void generate_name (struct config *, const char *filename);
static void generate_libvirt_xml (struct config *, struct data_conn *, const char *filename);
static void generate_wrapper_script (struct config *, const char *remote_dir, const char *filename);
static void generate_system_data (const char *dmesg_file, const char *lscpu_file, const char *lspci_file, const char *lsscsi_file, const char *lsusb_file);
static const char *map_interface_to_network (struct config *, const char *interface);
static void print_quoted (FILE *fp, const char *s);

static char *conversion_error;

static void set_conversion_error (const char *fs, ...)
  __attribute__((format(printf,1,2)));

static void
set_conversion_error (const char *fs, ...)
{
  va_list args;
  char *msg;
  int len;

  va_start (args, fs);
  len = vasprintf (&msg, fs, args);
  va_end (args);

  if (len < 0)
    error (EXIT_FAILURE, errno,
           "vasprintf (original error format string: %s)", fs);

  free (conversion_error);
  conversion_error = msg;
}

const char *
get_conversion_error (void)
{
  return conversion_error;
}

static pthread_mutex_t running_mutex = PTHREAD_MUTEX_INITIALIZER;
static int running = 0;
static pthread_mutex_t cancel_requested_mutex = PTHREAD_MUTEX_INITIALIZER;
static int cancel_requested = 0;
static mexp_h *control_h = NULL;

static int
is_running (void)
{
  int r;
  pthread_mutex_lock (&running_mutex);
  r = running;
  pthread_mutex_unlock (&running_mutex);
  return r;
}

static void
set_running (int r)
{
  pthread_mutex_lock (&running_mutex);
  running = r;
  pthread_mutex_unlock (&running_mutex);
}

static int
is_cancel_requested (void)
{
  int r;
  pthread_mutex_lock (&cancel_requested_mutex);
  r = cancel_requested;
  pthread_mutex_unlock (&cancel_requested_mutex);
  return r;
}

static void
set_cancel_requested (int r)
{
  pthread_mutex_lock (&cancel_requested_mutex);
  cancel_requested = r;

  /* Send ^C to the remote so that virt-v2v "knows" the connection has
   * been cancelled.  mexp_send_interrupt is a single write(2) call.
   */
  if (r && control_h)
    ignore_value (mexp_send_interrupt (control_h));

  pthread_mutex_unlock (&cancel_requested_mutex);
}

static void
set_control_h (mexp_h *new_h)
{
  pthread_mutex_lock (&cancel_requested_mutex);
  control_h = new_h;
  pthread_mutex_unlock (&cancel_requested_mutex);
}

#pragma GCC diagnostic ignored "-Wsuggest-attribute=noreturn"
int
start_conversion (struct config *config,
                  void (*notify_ui) (int type, const char *data))
{
  int ret = -1;
  int status;
  size_t i, len;
  const size_t nr_disks = guestfs_int_count_strings (config->disks);
  time_t now;
  struct tm tm;
  CLEANUP_FREE struct data_conn *data_conns = NULL;
  CLEANUP_FREE char *remote_dir = NULL;
  char tmpdir[]           = "/tmp/p2v.XXXXXX";
  char name_file[]        = "/tmp/p2v.XXXXXX/name";
  char libvirt_xml_file[] = "/tmp/p2v.XXXXXX/physical.xml";
  char wrapper_script[]   = "/tmp/p2v.XXXXXX/virt-v2v-wrapper.sh";
  char dmesg_file[]       = "/tmp/p2v.XXXXXX/dmesg";
  char lscpu_file[]       = "/tmp/p2v.XXXXXX/lscpu";
  char lspci_file[]       = "/tmp/p2v.XXXXXX/lspci";
  char lsscsi_file[]      = "/tmp/p2v.XXXXXX/lsscsi";
  char lsusb_file[]       = "/tmp/p2v.XXXXXX/lsusb";
  int inhibit_fd = -1;

#if DEBUG_STDERR
  print_config (config, stderr);
  fprintf (stderr, "\n");
#endif

  set_control_h (NULL);
  set_running (1);
  set_cancel_requested (0);

  inhibit_fd = inhibit_power_saving ();
#ifdef DEBUG_STDERR
  if (inhibit_fd == -1)
    fprintf (stderr, "warning: virt-p2v cannot inhibit power saving during conversion.\n");
#endif

  data_conns = malloc (sizeof (struct data_conn) * nr_disks);
  if (data_conns == NULL)
    error (EXIT_FAILURE, errno, "malloc");

  for (i = 0; config->disks[i] != NULL; ++i) {
    data_conns[i].h = NULL;
    data_conns[i].nbd_pid = 0;
    data_conns[i].nbd_local_port = -1;
    data_conns[i].nbd_remote_port = -1;
  }

  /* Start the data connections and qemu-nbd processes, one per disk. */
  for (i = 0; config->disks[i] != NULL; ++i) {
    CLEANUP_FREE char *device = NULL;

    if (notify_ui) {
      CLEANUP_FREE char *msg;
      if (asprintf (&msg,
                    _("Opening data connection for %s ..."),
                    config->disks[i]) == -1)
        error (EXIT_FAILURE, errno, "asprintf");
      notify_ui (NOTIFY_STATUS, msg);
    }

    data_conns[i].h = open_data_connection (config,
                                            &data_conns[i].nbd_local_port,
                                            &data_conns[i].nbd_remote_port);
    if (data_conns[i].h == NULL) {
      const char *err = get_ssh_error ();

      set_conversion_error ("could not open data connection over SSH to the conversion server: %s", err);
      goto out;
    }

    if (config->disks[i][0] == '/') {
      device = strdup (config->disks[i]);
      if (!device) {
        perror ("strdup");
        cleanup_data_conns (data_conns, nr_disks);
        exit (EXIT_FAILURE);
      }
    }
    else if (asprintf (&device, "/dev/%s", config->disks[i]) == -1) {
      perror ("asprintf");
      cleanup_data_conns (data_conns, nr_disks);
      exit (EXIT_FAILURE);
    }

#if DEBUG_STDERR
    fprintf (stderr,
             "%s: data connection for %s: SSH remote port %d, local port %d\n",
             getprogname (), device,
             data_conns[i].nbd_remote_port, data_conns[i].nbd_local_port);
#endif

    /* Start qemu-nbd listening on the given port number. */
    data_conns[i].nbd_pid =
      start_qemu_nbd (data_conns[i].nbd_local_port, device);
    if (data_conns[i].nbd_pid == 0)
      goto out;

    /* Wait for qemu-nbd to listen */
    if (wait_qemu_nbd (data_conns[i].nbd_local_port,
                       WAIT_QEMU_NBD_TIMEOUT) == -1)
      goto out;
  }

  /* Create a remote directory name which will be used for libvirt
   * XML, log files and other stuff.  We don't delete this directory
   * after the run because (a) it's useful for debugging and (b) it
   * only contains small files.
   *
   * NB: This path MUST NOT require shell quoting.
   */
  time (&now);
  gmtime_r (&now, &tm);
  if (asprintf (&remote_dir,
                "/tmp/virt-p2v-%04d%02d%02d-XXXXXXXX",
                tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday) == -1) {
    perror ("asprintf");
    cleanup_data_conns (data_conns, nr_disks);
    exit (EXIT_FAILURE);
  }
  len = strlen (remote_dir);
  guestfs_int_random_string (&remote_dir[len-8], 8);
  if (notify_ui)
    notify_ui (NOTIFY_LOG_DIR, remote_dir);

  /* Generate the local temporary directory. */
  if (mkdtemp (tmpdir) == NULL) {
    perror ("mkdtemp");
    cleanup_data_conns (data_conns, nr_disks);
    exit (EXIT_FAILURE);
  }
  memcpy (name_file, tmpdir, strlen (tmpdir));
  memcpy (libvirt_xml_file, tmpdir, strlen (tmpdir));
  memcpy (wrapper_script, tmpdir, strlen (tmpdir));
  memcpy (dmesg_file, tmpdir, strlen (tmpdir));
  memcpy (lscpu_file, tmpdir, strlen (tmpdir));
  memcpy (lspci_file, tmpdir, strlen (tmpdir));
  memcpy (lsscsi_file, tmpdir, strlen (tmpdir));
  memcpy (lsusb_file, tmpdir, strlen (tmpdir));

  /* Generate the static files. */
  generate_name (config, name_file);
  generate_libvirt_xml (config, data_conns, libvirt_xml_file);
  generate_wrapper_script (config, remote_dir, wrapper_script);
  generate_system_data (dmesg_file,
                        lscpu_file, lspci_file, lsscsi_file, lsusb_file);

  /* Open the control connection.  This also creates remote_dir. */
  if (notify_ui)
    notify_ui (NOTIFY_STATUS, _("Setting up the control connection ..."));

  set_control_h (start_remote_connection (config, remote_dir));
  if (control_h == NULL) {
    set_conversion_error ("could not open control connection over SSH to the conversion server: %s",
                          get_ssh_error ());
    goto out;
  }

  /* Copy the static files to the remote dir. */
  if (scp_file (config, name_file, remote_dir) == -1) {
    set_conversion_error ("scp: %s to %s: %s",
                          name_file, remote_dir, get_ssh_error ());
    goto out;
  }
  if (scp_file (config, libvirt_xml_file, remote_dir) == -1) {
    set_conversion_error ("scp: %s to %s: %s",
                          libvirt_xml_file, remote_dir, get_ssh_error ());
    goto out;
  }
  if (scp_file (config, wrapper_script, remote_dir) == -1) {
    set_conversion_error ("scp: %s to %s: %s",
                          wrapper_script, remote_dir, get_ssh_error ());
    goto out;
  }
  /* It's not essential that these files are copied. */
  ignore_value (scp_file (config, dmesg_file, remote_dir));
  ignore_value (scp_file (config, lscpu_file, remote_dir));
  ignore_value (scp_file (config, lspci_file, remote_dir));
  ignore_value (scp_file (config, lsscsi_file, remote_dir));
  ignore_value (scp_file (config, lsusb_file, remote_dir));

  /* Do the conversion.  This runs until virt-v2v exits. */
  if (notify_ui)
    notify_ui (NOTIFY_STATUS, _("Doing conversion ..."));

  if (mexp_printf (control_h,
                   /* To simplify things in the wrapper script, it
                    * writes virt-v2v's exit status to
                    * /remote_dir/status, and here we read that and
                    * exit the ssh shell with the same status.
                    */
                   "%s/virt-v2v-wrapper.sh; "
                   "exit $(< %s/status)\n",
                   remote_dir, remote_dir) == -1) {
    set_conversion_error ("mexp_printf: virt-v2v: %m");
    goto out;
  }

  /* Read output from the virt-v2v process and echo it through the
   * notify function, until virt-v2v closes the connection.
   */
  while (!is_cancel_requested ()) {
    char buf[257];
    ssize_t r;

    r = read (mexp_get_fd (control_h), buf, sizeof buf - 1);
    if (r == -1) {
      /* See comment about this in miniexpect.c. */
      if (errno == EIO)
        break;                  /* EOF */
      set_conversion_error ("read: %m");
      goto out;
    }
    if (r == 0)
      break;                    /* EOF */
    buf[r] = '\0';
    if (notify_ui)
      notify_ui (NOTIFY_REMOTE_MESSAGE, buf);
  }

  if (is_cancel_requested ()) {
    set_conversion_error ("cancelled by user");
    if (notify_ui)
      notify_ui (NOTIFY_STATUS, _("Conversion cancelled by user."));
    goto out;
  }

  if (notify_ui)
    notify_ui (NOTIFY_STATUS, _("Control connection closed by remote."));

  ret = 0;
 out:
  if (control_h) {
    mexp_h *h = control_h;
    set_control_h (NULL);
    status = mexp_close (h);

    if (status == -1) {
      set_conversion_error ("mexp_close: %m");
      ret = -1;
    }
    else if (ret == 0 &&
             WIFEXITED (status) &&
             WEXITSTATUS (status) != 0) {
      set_conversion_error ("virt-v2v exited with status %d",
                            WEXITSTATUS (status));
      ret = -1;
    }
  }
  cleanup_data_conns (data_conns, nr_disks);

  if (inhibit_fd >= 0)
    close (inhibit_fd);

  set_running (0);

  return ret;
}

int
conversion_is_running (void)
{
  return is_running ();
}

void
cancel_conversion (void)
{
  set_cancel_requested (1);
}

/**
 * Start a local L<qemu-nbd(1)> process.
 *
 * Returns the process ID (E<gt> 0) or C<0> if there is an error.
 */
static pid_t
start_qemu_nbd (int port, const char *device)
{
  pid_t pid;
  char port_str[64];

  snprintf (port_str, sizeof port_str, "%d", port);

  pid = fork ();
  if (pid == -1) {
    set_conversion_error ("fork: %m");
    return 0;
  }

  if (pid == 0) {               /* Child. */
    close (0);
    open ("/dev/null", O_RDONLY);

    execlp ("qemu-nbd",
            "qemu-nbd",
            "-r",               /* readonly (vital!) */
            "-p", port_str,     /* listening port */
            "-t",               /* persistent */
            "-f", "raw",        /* force raw format */
            "-b", "localhost",  /* listen only on loopback interface */
            "--cache=unsafe",   /* use unsafe caching for speed */
            device,             /* a device like /dev/sda */
            NULL);
    perror ("qemu-nbd");
    _exit (EXIT_FAILURE);
  }

  /* Parent. */
  return pid;
}

static int bind_source_port (int sockfd, int family, int source_port);

/**
 * Connect to C<hostname:dest_port>, resolving the address using
 * L<getaddrinfo(3)>.
 *
 * This also sets the source port of the connection to the first free
 * port number E<ge> C<source_port>.
 *
 * This may involve multiple connections - to IPv4 and IPv6 for
 * instance.
 */
static int
connect_with_source_port (const char *hostname, int dest_port, int source_port)
{
  struct addrinfo hints;
  struct addrinfo *results, *rp;
  char dest_port_str[16];
  int r, sockfd = -1;
  int reuseaddr = 1;

  snprintf (dest_port_str, sizeof dest_port_str, "%d", dest_port);

  memset (&hints, 0, sizeof hints);
  hints.ai_family = AF_UNSPEC;     /* allow IPv4 or IPv6 */
  hints.ai_socktype = SOCK_STREAM;
  hints.ai_flags = AI_NUMERICSERV; /* numeric dest port number */
  hints.ai_protocol = 0;           /* any protocol */

  r = getaddrinfo (hostname, dest_port_str, &hints, &results);
  if (r != 0) {
    set_conversion_error ("getaddrinfo: %s/%s: %s",
                          hostname, dest_port_str, gai_strerror (r));
    return -1;
  }

  for (rp = results; rp != NULL; rp = rp->ai_next) {
    sockfd = socket (rp->ai_family, rp->ai_socktype, rp->ai_protocol);
    if (sockfd == -1)
      continue;

    /* If we run p2v repeatedly (say, running the tests in a loop),
     * there's a decent chance we'll end up trying to bind() to a port
     * that is in TIME_WAIT from a prior run.  Handle that gracefully
     * with SO_REUSEADDR.
     */
    if (setsockopt (sockfd, SOL_SOCKET, SO_REUSEADDR,
                    &reuseaddr, sizeof reuseaddr) == -1)
      perror ("warning: setsockopt");

    /* Need to bind the source port. */
    if (bind_source_port (sockfd, rp->ai_family, source_port) == -1) {
      close (sockfd);
      sockfd = -1;
      continue;
    }

    /* Connect. */
    if (connect (sockfd, rp->ai_addr, rp->ai_addrlen) == -1) {
      set_conversion_error ("waiting for qemu-nbd to start: "
                            "connect to %s/%s: %m",
                            hostname, dest_port_str);
      close (sockfd);
      sockfd = -1;
      continue;
    }

    break;
  }

  freeaddrinfo (results);
  return sockfd;
}

static int
bind_source_port (int sockfd, int family, int source_port)
{
  struct addrinfo hints;
  struct addrinfo *results, *rp;
  char source_port_str[16];
  int r;

  snprintf (source_port_str, sizeof source_port_str, "%d", source_port);

  memset (&hints, 0, sizeof (hints));
  hints.ai_family = family;
  hints.ai_socktype = SOCK_STREAM;
  hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV; /* numeric port number */
  hints.ai_protocol = 0;                        /* any protocol */

  r = getaddrinfo ("localhost", source_port_str, &hints, &results);
  if (r != 0) {
    set_conversion_error ("getaddrinfo (bind): localhost/%s: %s",
                          source_port_str, gai_strerror (r));
    return -1;
  }

  for (rp = results; rp != NULL; rp = rp->ai_next) {
    if (bind (sockfd, rp->ai_addr, rp->ai_addrlen) == 0)
      goto bound;
  }

  set_conversion_error ("waiting for qemu-nbd to start: "
                        "bind to source port %d: %m",
                        source_port);
  freeaddrinfo (results);
  return -1;

 bound:
  freeaddrinfo (results);
  return 0;
}

static int
wait_qemu_nbd (int nbd_local_port, int timeout_seconds)
{
  int sockfd = -1;
  int result = -1;
  time_t start_t, now_t;
  struct timespec half_sec = { .tv_sec = 0, .tv_nsec = 500000000 };
  struct timeval timeout = { .tv_usec = 0 };
  char magic[8]; /* NBDMAGIC */
  size_t bytes_read = 0;
  ssize_t recvd;

  time (&start_t);

  for (;;) {
    time (&now_t);

    if (now_t - start_t >= timeout_seconds)
      goto cleanup;

    /* Source port for probing qemu-nbd should be one greater than
     * nbd_local_port.  It's not guaranteed to always bind to this port,
     * but it will hint the kernel to start there and try incrementally
     * higher ports if needed.  This avoids the case where the kernel
     * selects nbd_local_port as our source port, and we immediately
     * connect to ourself.  See:
     * https://bugzilla.redhat.com/show_bug.cgi?id=1167774#c9
     */
    sockfd = connect_with_source_port ("localhost", nbd_local_port,
                                       nbd_local_port+1);
    if (sockfd >= 0)
      break;

    nanosleep (&half_sec, NULL);
  }

  time (&now_t);
  timeout.tv_sec = (start_t + timeout_seconds) - now_t;
  setsockopt (sockfd, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof timeout);

  do {
    recvd = recv (sockfd, magic, sizeof magic - bytes_read, 0);

    if (recvd == -1) {
      set_conversion_error ("waiting for qemu-nbd to start: recv: %m");
      goto cleanup;
    }

    bytes_read += recvd;
  } while (bytes_read < sizeof magic);

  if (memcmp (magic, "NBDMAGIC", sizeof magic) != 0) {
    set_conversion_error ("waiting for qemu-nbd to start: "
                          "'NBDMAGIC' was not received from qemu-nbd");
    goto cleanup;
  }

  result = 0;
 cleanup:
  close (sockfd);

  return result;
}

static void
cleanup_data_conns (struct data_conn *data_conns, size_t nr)
{
  size_t i;

  for (i = 0; i < nr; ++i) {
    if (data_conns[i].h != NULL) {
      /* Because there is no SSH prompt (ssh -N), the only way to kill
       * these ssh connections is to send a signal.  Just closing the
       * pipe doesn't do anything.
       */
      kill (mexp_get_pid (data_conns[i].h), SIGHUP);
      mexp_close (data_conns[i].h);
    }

    if (data_conns[i].nbd_pid > 0) {
      /* Kill qemu-nbd process and clean up. */
      kill (data_conns[i].nbd_pid, SIGTERM);
      waitpid (data_conns[i].nbd_pid, NULL, 0);
    }
  }
}

/* Macros "inspired" by lib/launch-libvirt.c */
/* <element */
#define start_element(element)						\
  if (xmlTextWriterStartElement (xo, BAD_CAST (element)) == -1)         \
    error (EXIT_FAILURE, errno, "xmlTextWriterStartElement");		\
  do

/* finish current </element> */
#define end_element()						\
  while (0);							\
  do {								\
    if (xmlTextWriterEndElement (xo) == -1)			\
      error (EXIT_FAILURE, errno, "xmlTextWriterEndElement");	\
  } while (0)

/* <element/> */
#define empty_element(element)					\
  do { start_element(element) {} end_element (); } while (0)

/* key=value attribute of the current element. */
#define attribute(key,value)                                            \
  do {                                                                  \
    if (xmlTextWriterWriteAttribute (xo, BAD_CAST (key), BAD_CAST (value)) == -1) \
    error (EXIT_FAILURE, errno, "xmlTextWriterWriteAttribute");         \
  } while (0)

/* key=value, but value is a printf-style format string. */
#define attribute_format(key,fs,...)                                    \
  do {                                                                  \
    if (xmlTextWriterWriteFormatAttribute (xo, BAD_CAST (key),          \
                                           fs, ##__VA_ARGS__) == -1)	\
      error (EXIT_FAILURE, errno, "xmlTextWriterWriteFormatAttribute"); \
  } while (0)

/* A string, eg. within an element. */
#define string(str)                                             \
  do {                                                          \
    if (xmlTextWriterWriteString (xo, BAD_CAST (str)) == -1)	\
      error (EXIT_FAILURE, errno, "xmlTextWriterWriteString");	\
  } while (0)

/* A string, using printf-style formatting. */
#define string_format(fs,...)                                           \
  do {                                                                  \
    if (xmlTextWriterWriteFormatString (xo, fs, ##__VA_ARGS__) == -1)   \
      error (EXIT_FAILURE, errno, "xmlTextWriterWriteFormatString");    \
  } while (0)

/* An XML comment. */
#define comment(str)						\
  do {                                                          \
    if (xmlTextWriterWriteComment (xo, BAD_CAST (str)) == -1)	\
      error (EXIT_FAILURE, errno, "xmlTextWriterWriteComment");	\
  } while (0)

/**
 * Write the libvirt XML for this physical machine.
 *
 * Note this is not actually input for libvirt.  It's input for
 * virt-v2v on the conversion server.  Virt-v2v will (if necessary)
 * generate the final libvirt XML.
 */
static void
generate_libvirt_xml (struct config *config, struct data_conn *data_conns,
                      const char *filename)
{
  uint64_t memkb;
  CLEANUP_XMLFREETEXTWRITER xmlTextWriterPtr xo = NULL;
  size_t i;

  xo = xmlNewTextWriterFilename (filename, 0);
  if (xo == NULL)
    error (EXIT_FAILURE, errno, "xmlNewTextWriterFilename");

  if (xmlTextWriterSetIndent (xo, 1) == -1 ||
      xmlTextWriterSetIndentString (xo, BAD_CAST "  ") == -1)
    error (EXIT_FAILURE, errno, "could not set XML indent");
  if (xmlTextWriterStartDocument (xo, NULL, NULL, NULL) == -1)
    error (EXIT_FAILURE, errno, "xmlTextWriterStartDocument");

  memkb = config->memory / 1024;

  comment
    (" NOTE!\n"
     "\n"
     "  This libvirt XML is generated by the virt-p2v front end, in\n"
     "  order to communicate with the backend virt-v2v process running\n"
     "  on the conversion server.  It is a minimal description of the\n"
     "  physical machine.  If the target of the conversion is libvirt,\n"
     "  then virt-v2v will generate the real target libvirt XML, which\n"
     "  has only a little to do with the XML in this file.\n"
     "\n"
     "  TL;DR: Don't try to load this XML into libvirt. ");

  start_element ("domain") {
    attribute ("type", "physical");

    start_element ("name") {
      string (config->guestname);
    } end_element ();

    start_element ("memory") {
      attribute ("unit", "KiB");
      string_format ("%" PRIu64, memkb);
    } end_element ();

    start_element ("currentMemory") {
      attribute ("unit", "KiB");
      string_format ("%" PRIu64, memkb);
    } end_element ();

    start_element ("vcpu") {
      string_format ("%d", config->vcpus);
    } end_element ();

    start_element ("os") {
      start_element ("type") {
        attribute ("arch", host_cpu);
        string ("hvm");
      } end_element ();
    } end_element ();

    start_element ("features") {
      if (config->flags & FLAG_ACPI) empty_element ("acpi");
      if (config->flags & FLAG_APIC) empty_element ("apic");
      if (config->flags & FLAG_PAE)  empty_element ("pae");
    } end_element ();

    start_element ("devices") {

      for (i = 0; config->disks[i] != NULL; ++i) {
        char target_dev[64];

        if (config->disks[i][0] == '/') {
        target_sd:
          memcpy (target_dev, "sd", 2);
          guestfs_int_drive_name (i, &target_dev[2]);
        } else {
          if (strlen (config->disks[i]) <= sizeof (target_dev) - 1)
            strcpy (target_dev, config->disks[i]);
          else
            goto target_sd;
        }

        start_element ("disk") {
          attribute ("type", "network");
          attribute ("device", "disk");
          start_element ("driver") {
            attribute ("name", "qemu");
            attribute ("type", "raw");
          } end_element ();
          start_element ("source") {
            attribute ("protocol", "nbd");
            start_element ("host") {
              attribute ("name", "localhost");
              attribute_format ("port", "%d", data_conns[i].nbd_remote_port);
            } end_element ();
          } end_element ();
          start_element ("target") {
            attribute ("dev", target_dev);
            /* XXX Need to set bus to "ide" or "scsi" here. */
          } end_element ();
        } end_element ();
      }

      if (config->removable) {
        for (i = 0; config->removable[i] != NULL; ++i) {
          start_element ("disk") {
            attribute ("type", "network");
            attribute ("device", "cdrom");
            start_element ("driver") {
              attribute ("name", "qemu");
              attribute ("type", "raw");
            } end_element ();
            start_element ("target") {
              attribute ("dev", config->removable[i]);
            } end_element ();
          } end_element ();
        }
      }

      if (config->interfaces) {
        for (i = 0; config->interfaces[i] != NULL; ++i) {
          const char *target_network;
          CLEANUP_FREE char *mac_filename = NULL;
          CLEANUP_FREE char *mac = NULL;

          target_network =
            map_interface_to_network (config, config->interfaces[i]);

          if (asprintf (&mac_filename, "/sys/class/net/%s/address",
                        config->interfaces[i]) == -1)
            error (EXIT_FAILURE, errno, "asprintf");
          if (g_file_get_contents (mac_filename, &mac, NULL, NULL)) {
            const size_t len = strlen (mac);

            if (len > 0 && mac[len-1] == '\n')
              mac[len-1] = '\0';
          }

          start_element ("interface") {
            attribute ("type", "network");
            start_element ("source") {
              attribute ("network", target_network);
            } end_element ();
            start_element ("target") {
              attribute ("dev", config->interfaces[i]);
            } end_element ();
            if (mac) {
              start_element ("mac") {
                attribute ("address", mac);
              } end_element ();
            }
          } end_element ();
        }
      }

    } end_element (); /* </devices> */

  } end_element (); /* </domain> */

  if (xmlTextWriterEndDocument (xo) == -1)
    error (EXIT_FAILURE, errno, "xmlTextWriterEndDocument");
}

/**
 * Using C<config-E<gt>network_map>, map the interface to a target
 * network name.  If no map is found, return C<default>.  See
 * L<virt-p2v(1)> documentation of C<"p2v.network"> for how the
 * network map works.
 *
 * Note this returns a static string which is only valid as long as
 * C<config-E<gt>network_map> is not freed.
 */
static const char *
map_interface_to_network (struct config *config, const char *interface)
{
  size_t i, len;

  if (config->network_map == NULL)
    return "default";

  for (i = 0; config->network_map[i] != NULL; ++i) {
    /* The default map maps everything. */
    if (strchr (config->network_map[i], ':') == NULL)
      return config->network_map[i];

    /* interface: ? */
    len = strlen (interface);
    if (STRPREFIX (config->network_map[i], interface) &&
        config->network_map[i][len] == ':')
      return &config->network_map[i][len+1];
  }

  /* No mapping found. */
  return "default";
}

/**
 * Write the guest name into C<filename>.
 */
static void
generate_name (struct config *config, const char *filename)
{
  FILE *fp;

  fp = fopen (filename, "w");
  if (fp == NULL)
    error (EXIT_FAILURE, errno, "fopen: %s", filename);
  fprintf (fp, "%s\n", config->guestname);
  fclose (fp);
}

/**
 * Construct the virt-v2v wrapper script.
 *
 * This will be sent to the remote server, and is easier than trying
 * to "type" a long and complex single command line into the ssh
 * connection when we start the conversion.
 */
static void
generate_wrapper_script (struct config *config, const char *remote_dir,
                         const char *filename)
{
  FILE *fp;

  fp = fopen (filename, "w");
  if (fp == NULL)
    error (EXIT_FAILURE, errno, "fopen: %s", filename);

  fprintf (fp, "#!/bin/bash -\n");
  fprintf (fp, "\n");

  fprintf (fp, "cd %s\n", remote_dir);
  fprintf (fp, "\n");

  /* The virt-v2v command, as a shell function called "v2v". */
  fprintf (fp, "v2v ()\n");
  fprintf (fp, "{\n");
  if (config->sudo)
    fprintf (fp, "sudo -n ");
  fprintf (fp, "virt-v2v -v -x");
  if (feature_colours_option)
    fprintf (fp, " --colours");
  fprintf (fp, " -i libvirtxml");

  if (config->output) {         /* -o */
    fprintf (fp, " -o ");
    print_quoted (fp, config->output);
  }

  switch (config->output_allocation) { /* -oa */
  case OUTPUT_ALLOCATION_NONE:
    /* nothing */
    break;
  case OUTPUT_ALLOCATION_SPARSE:
    fprintf (fp, " -oa sparse");
    break;
  case OUTPUT_ALLOCATION_PREALLOCATED:
    fprintf (fp, " -oa preallocated");
    break;
  default:
    abort ();
  }

  if (config->output_format) {  /* -of */
    fprintf (fp, " -of ");
    print_quoted (fp, config->output_format);
  }

  if (config->output_storage) { /* -os */
    fprintf (fp, " -os ");
    print_quoted (fp, config->output_storage);
  }

  fprintf (fp, " --root first");
  fprintf (fp, " physical.xml");
  fprintf (fp, " </dev/null");  /* no stdin */
  fprintf (fp, "\n");
  fprintf (fp,
           "# Save the exit code of virt-v2v into the 'status' file.\n");
  fprintf (fp, "echo $? > status\n");
  fprintf (fp, "}\n");
  fprintf (fp, "\n");

  fprintf (fp,
           "# Write a pre-emptive error status, in case the virt-v2v\n"
           "# command doesn't get to run at all.  This will be\n"
           "# overwritten with the true exit code when virt-v2v runs.\n");
  fprintf (fp, "echo 99 > status\n");
  fprintf (fp, "\n");

  fprintf (fp, "log=virt-v2v-conversion-log.txt\n");
  fprintf (fp, "rm -f $log\n");
  fprintf (fp, "\n");

  fprintf (fp,
           "# Log the environment where virt-v2v will run.\n");
  fprintf (fp, "printenv > environment\n");
  fprintf (fp, "\n");

  fprintf (fp,
           "# Run virt-v2v.  Send stdout back to virt-p2v.  Send stdout\n"
           "# and stderr (debugging info) to the log file.\n");
  fprintf (fp, "v2v 2>> $log | tee -a $log\n");
  fprintf (fp, "\n");

  fprintf (fp,
           "# If virt-v2v failed then the error message (sent to stderr)\n"
           "# will not be seen in virt-p2v.  Send the last few lines of\n"
           "# the log back to virt-p2v in this case.\n");
  fprintf (fp,
           "if [ \"$(< status)\" -ne 0 ]; then\n"
           "    echo\n"
           "    echo\n"
           "    echo\n"
           "    echo -ne '\\e[1;31m'\n"
           "    echo '***' virt-v2v command failed '***'\n"
           "    echo\n"
           "    echo The full log is available on the conversion server in:\n"
           "    echo '   ' %s/$log\n"
           "    echo Only the last 50 lines are shown below.\n"
           "    echo -ne '\\e[0m'\n"
           "    echo\n"
           "    echo\n"
           "    echo\n"
           "    tail -50 $log\n"
           "fi\n",
           remote_dir);

  fprintf (fp, "\n");
  fprintf (fp, "# EOF\n");
  fclose (fp);

  if (chmod (filename, 0755) == -1)
    error (EXIT_FAILURE, errno, "chmod: %s", filename);
}

/**
 * Print a shell-quoted string on C<fp>.
 */
static void
print_quoted (FILE *fp, const char *s)
{
  fprintf (fp, "\"");
  while (*s) {
    if (*s == '$' || *s == '`' || *s == '\\' || *s == '"')
      fprintf (fp, "\\");
    fprintf (fp, "%c", *s);
    ++s;
  }
  fprintf (fp, "\"");
}

/**
 * Collect data about the system running virt-p2v such as the dmesg
 * output and lists of PCI devices.  This is useful for diagnosis when
 * things go wrong.
 *
 * If any command fails, this is non-fatal.
 */
static void
generate_system_data (const char *dmesg_file,
                      const char *lscpu_file,
                      const char *lspci_file,
                      const char *lsscsi_file,
                      const char *lsusb_file)
{
  CLEANUP_FREE char *cmd = NULL;

  if (asprintf (&cmd,
                "dmesg >%s 2>&1; "
                "lscpu >%s 2>&1; "
                "lspci -vvv >%s 2>&1; "
                "lsscsi -v >%s 2>&1; "
                "lsusb -v >%s 2>&1",
                dmesg_file, lscpu_file, lspci_file, lsscsi_file, lsusb_file)
      == -1)
    error (EXIT_FAILURE, errno, "asprintf");

  ignore_value (system (cmd));
}