/* virt-v2v
 * Copyright (C) 2009-2016 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 module implements various C<virsh>-like commands, but with
 * non-broken authentication handling.
 */

#include <config.h>

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <errno.h>
#include <libintl.h>

#include <caml/alloc.h>
#include <caml/fail.h>
#include <caml/memory.h>
#include <caml/mlvalues.h>

#ifdef HAVE_LIBVIRT
#include <libvirt/libvirt.h>
#include <libvirt/virterror.h>
#endif

#include "guestfs.h"
#include "guestfs-internal-frontend.h"

#pragma GCC diagnostic ignored "-Wmissing-prototypes"

#ifdef HAVE_LIBVIRT

#define ERROR_MESSAGE_LEN 512

static void
ignore_errors (void *ignore, virErrorPtr ignore2)
{
  /* empty */
}

/* Get the remote domain state (running, etc.).  Use virDomainGetState
 * which is most efficient, but if it's not implemented, fall back to
 * virDomainGetInfo.  See equivalent code in virsh.
 */
static int
get_dom_state (virDomainPtr dom)
{
  int state, reason;
  virErrorPtr err;
  virDomainInfo info;

  if (virDomainGetState (dom, &state, &reason, 0) == 0)
    return state;

  err = virGetLastError ();
  if (!err || err->code != VIR_ERR_NO_SUPPORT)
    return -1;

  if (virDomainGetInfo (dom, &info) == 0)
    return info.state;

  return -1;
}

/* See src/libvirt-auth.c for why we need this. */
static int
libvirt_auth_default_wrapper (virConnectCredentialPtr cred,
                              unsigned int ncred,
                              void *passwordvp)
{
  const char *password = passwordvp;
  unsigned int i;

  if (password) {
    /* If --password-file was specified on the command line, and the
     * libvirt handler is asking for a password, return that.
     */
    for (i = 0; i < ncred; ++i) {
      if (cred[i].type == VIR_CRED_PASSPHRASE) {
        cred[i].result = strdup (password);
        cred[i].resultlen = strlen (password);
      }
      else {
        cred[i].result = NULL;
        cred[i].resultlen = 0;
      }
    }
    return 0;
  }
  else {
    /* No --password-file so call the default handler. */
    return virConnectAuthPtrDefault->cb (cred, ncred,
                                         virConnectAuthPtrDefault->cbdata);
  }
}

virStoragePoolPtr
connect_and_load_pool (value connv, value poolnamev)
{
  CAMLparam2 (connv, poolnamev);
  const char *conn_uri = NULL;
  const char *poolname;
  /* We have to assemble the error on the stack because a dynamic
   * string couldn't be freed.
   */
  char errmsg[ERROR_MESSAGE_LEN];
  virErrorPtr err;
  virConnectPtr conn;
  virStoragePoolPtr pool;

  if (connv != Val_int (0))
    conn_uri = String_val (Field (connv, 0)); /* Some conn */

  /* We have to call the default authentication handler, not least
   * since it handles all the PolicyKit crap.  However it also makes
   * coding this simpler.
   */
  conn = virConnectOpenAuth (conn_uri, virConnectAuthPtrDefault,
                             VIR_CONNECT_RO);
  if (conn == NULL) {
    if (conn_uri)
      snprintf (errmsg, sizeof errmsg,
                _("cannot open libvirt connection '%s'"), conn_uri);
    else
      snprintf (errmsg, sizeof errmsg, _("cannot open libvirt connection"));
    caml_invalid_argument (errmsg);
  }

  /* Suppress default behaviour of printing errors to stderr.  Note
   * you can't set this to NULL to ignore errors; setting it to NULL
   * restores the default error handler ...
   */
  virConnSetErrorFunc (conn, NULL, ignore_errors);

  /* Look up the pool. */
  poolname = String_val (poolnamev);

  pool = virStoragePoolLookupByUUIDString (conn, poolname);

  if (!pool)
    pool = virStoragePoolLookupByName (conn, poolname);

  if (!pool) {
    err = virGetLastError ();
    snprintf (errmsg, sizeof errmsg,
              _("cannot find libvirt pool '%s': %s\n\nUse `virsh pool-list --all' to list all available pools, and `virsh pool-dumpxml <pool>' to display details about a particular pool.\n\nTo set the pool which virt-v2v uses, add the `-os <pool>' option."),
              poolname, err->message);
    virConnectClose (conn);
    caml_invalid_argument (errmsg);
  }

  CAMLreturnT (virStoragePoolPtr, pool);
}

value
v2v_dumpxml (value passwordv, value connv, value domnamev)
{
  CAMLparam3 (passwordv, connv, domnamev);
  CAMLlocal1 (retv);
  const char *password = NULL;
  const char *conn_uri = NULL;
  const char *domname;
  virConnectAuth authdata;
  /* We have to assemble the error on the stack because a dynamic
   * string couldn't be freed.
   */
  char errmsg[ERROR_MESSAGE_LEN];
  virErrorPtr err;
  virConnectPtr conn;
  virDomainPtr dom;
  int is_test_uri = 0;
  char *xml;

  if (passwordv != Val_int (0))
    password = String_val (Field (passwordv, 0)); /* Some password */

  if (connv != Val_int (0)) {
    conn_uri = String_val (Field (connv, 0)); /* Some conn */
    is_test_uri = STRPREFIX (conn_uri, "test:");
  }

  /* Set up authentication wrapper. */
  authdata = *virConnectAuthPtrDefault;
  authdata.cb = libvirt_auth_default_wrapper;
  authdata.cbdata = (void *) password;

  /* Note this cannot be a read-only connection since we need to use
   * the VIR_DOMAIN_XML_SECURE flag below.
   */
  conn = virConnectOpenAuth (conn_uri, &authdata, 0);
  if (conn == NULL) {
    if (conn_uri)
      snprintf (errmsg, sizeof errmsg,
                _("cannot open libvirt connection '%s'"), conn_uri);
    else
      snprintf (errmsg, sizeof errmsg, _("cannot open libvirt connection"));
    caml_invalid_argument (errmsg);
  }

  /* Suppress default behaviour of printing errors to stderr.  Note
   * you can't set this to NULL to ignore errors; setting it to NULL
   * restores the default error handler ...
   */
  virConnSetErrorFunc (conn, NULL, ignore_errors);

  /* Look up the domain. */
  domname = String_val (domnamev);

  dom = virDomainLookupByUUIDString (conn, domname);

  if (!dom)
    dom = virDomainLookupByName (conn, domname);

  if (!dom) {
    err = virGetLastError ();
    snprintf (errmsg, sizeof errmsg,
              _("cannot find libvirt domain '%s': %s"), domname, err->message);
    virConnectClose (conn);
    caml_invalid_argument (errmsg);
  }

  /* As a side-effect we check that the domain is shut down.  Of course
   * this is only appropriate for virt-v2v.  (RHBZ#1138586)
   */
  if (!is_test_uri) {
    const int state = get_dom_state (dom);

    if (state == VIR_DOMAIN_RUNNING ||
        state == VIR_DOMAIN_BLOCKED ||
        state == VIR_DOMAIN_PAUSED) {
      snprintf (errmsg, sizeof errmsg,
                _("libvirt domain '%s' is running or paused.  It must be shut down in order to perform virt-v2v conversion"),
                domname);
      virDomainFree (dom);
      virConnectClose (conn);
      caml_invalid_argument (errmsg);
    }
  }

  /* Use VIR_DOMAIN_XML_SECURE to get passwords (RHBZ#1174123). */
  xml = virDomainGetXMLDesc (dom, VIR_DOMAIN_XML_SECURE);
  if (xml == NULL) {
    err = virGetLastError ();
    snprintf (errmsg, sizeof errmsg,
              _("cannot fetch XML description of guest '%s': %s"),
              domname, err->message);
    virDomainFree (dom);
    virConnectClose (conn);
    caml_invalid_argument (errmsg);
  }
  virDomainFree (dom);
  virConnectClose (conn);

  retv = caml_copy_string (xml);
  free (xml);

  CAMLreturn (retv);
}

value
v2v_pool_dumpxml (value connv, value poolnamev)
{
  CAMLparam2 (connv, poolnamev);
  CAMLlocal1 (retv);
  /* We have to assemble the error on the stack because a dynamic
   * string couldn't be freed.
   */
  char errmsg[ERROR_MESSAGE_LEN];
  virErrorPtr err;
  virConnectPtr conn;
  virStoragePoolPtr pool;
  char *xml;

  /* Look up the pool. */
  pool = connect_and_load_pool (connv, poolnamev);
  conn = virStoragePoolGetConnect (pool);

  xml = virStoragePoolGetXMLDesc (pool, 0);
  if (xml == NULL) {
    err = virGetLastError ();
    snprintf (errmsg, sizeof errmsg,
              _("cannot fetch XML description of pool '%s': %s"),
              String_val (poolnamev), err->message);
    virStoragePoolFree (pool);
    virConnectClose (conn);
    caml_invalid_argument (errmsg);
  }
  virStoragePoolFree (pool);
  virConnectClose (conn);

  retv = caml_copy_string (xml);
  free (xml);

  CAMLreturn (retv);
}

value
v2v_vol_dumpxml (value connv, value poolnamev, value volnamev)
{
  CAMLparam3 (connv, poolnamev, volnamev);
  CAMLlocal1 (retv);
  const char *volname;
  /* We have to assemble the error on the stack because a dynamic
   * string couldn't be freed.
   */
  char errmsg[ERROR_MESSAGE_LEN];
  virErrorPtr err;
  virConnectPtr conn;
  virStoragePoolPtr pool;
  virStorageVolPtr vol;
  char *xml;

  /* Look up the pool. */
  pool = connect_and_load_pool (connv, poolnamev);
  conn = virStoragePoolGetConnect (pool);

  /* Look up the volume. */
  volname = String_val (volnamev);

  vol = virStorageVolLookupByName (pool, volname);

  if (!vol) {
    err = virGetLastError ();
    snprintf (errmsg, sizeof errmsg,
              _("cannot find libvirt volume '%s': %s"), volname, err->message);
    virStoragePoolFree (pool);
    virConnectClose (conn);
    caml_invalid_argument (errmsg);
  }

  xml = virStorageVolGetXMLDesc (vol, 0);
  if (xml == NULL) {
    err = virGetLastError ();
    snprintf (errmsg, sizeof errmsg,
              _("cannot fetch XML description of volume '%s': %s"),
              volname, err->message);
    virStorageVolFree (vol);
    virStoragePoolFree (pool);
    virConnectClose (conn);
    caml_invalid_argument (errmsg);
  }
  virStorageVolFree (vol);
  virStoragePoolFree (pool);
  virConnectClose (conn);

  retv = caml_copy_string (xml);
  free (xml);

  CAMLreturn (retv);
}

value
v2v_capabilities (value connv, value unitv)
{
  CAMLparam2 (connv, unitv);
  CAMLlocal1 (capabilitiesv);
  const char *conn_uri = NULL;
  char *capabilities;
  /* We have to assemble the error on the stack because a dynamic
   * string couldn't be freed.
   */
  char errmsg[ERROR_MESSAGE_LEN];
  virErrorPtr err;
  virConnectPtr conn;

  if (connv != Val_int (0))
    conn_uri = String_val (Field (connv, 0)); /* Some conn */

  /* We have to call the default authentication handler, not least
   * since it handles all the PolicyKit crap.  However it also makes
   * coding this simpler.
   */
  conn = virConnectOpenAuth (conn_uri, virConnectAuthPtrDefault,
                             VIR_CONNECT_RO);
  if (conn == NULL) {
    if (conn_uri)
      snprintf (errmsg, sizeof errmsg,
                _("cannot open libvirt connection '%s'"), conn_uri);
    else
      snprintf (errmsg, sizeof errmsg, _("cannot open libvirt connection"));
    caml_invalid_argument (errmsg);
  }

  /* Suppress default behaviour of printing errors to stderr.  Note
   * you can't set this to NULL to ignore errors; setting it to NULL
   * restores the default error handler ...
   */
  virConnSetErrorFunc (conn, NULL, ignore_errors);

  capabilities = virConnectGetCapabilities (conn);
  if (!capabilities) {
    err = virGetLastError ();
    snprintf (errmsg, sizeof errmsg,
              _("cannot get libvirt hypervisor capabilities: %s"),
              err->message);
    virConnectClose (conn);
    caml_invalid_argument (errmsg);
  }

  capabilitiesv = caml_copy_string (capabilities);
  free (capabilities);

  virConnectClose (conn);

  CAMLreturn (capabilitiesv);
}

value
v2v_domain_exists (value connv, value domnamev)
{
  CAMLparam2 (connv, domnamev);
  const char *conn_uri = NULL;
  const char *domname;
  /* We have to assemble the error on the stack because a dynamic
   * string couldn't be freed.
   */
  char errmsg[ERROR_MESSAGE_LEN];
  virErrorPtr err;
  virConnectPtr conn;
  virDomainPtr dom;
  int domain_exists;

  if (connv != Val_int (0))
    conn_uri = String_val (Field (connv, 0)); /* Some conn */

  /* We have to call the default authentication handler, not least
   * since it handles all the PolicyKit crap.  However it also makes
   * coding this simpler.
   */
  conn = virConnectOpenAuth (conn_uri, virConnectAuthPtrDefault,
                             VIR_CONNECT_RO);
  if (conn == NULL) {
    if (conn_uri)
      snprintf (errmsg, sizeof errmsg,
                _("cannot open libvirt connection '%s'"), conn_uri);
    else
      snprintf (errmsg, sizeof errmsg, _("cannot open libvirt connection"));
    caml_invalid_argument (errmsg);
  }

  /* Suppress default behaviour of printing errors to stderr.  Note
   * you can't set this to NULL to ignore errors; setting it to NULL
   * restores the default error handler ...
   */
  virConnSetErrorFunc (conn, NULL, ignore_errors);

  /* Look up the domain. */
  domname = String_val (domnamev);
  dom = virDomainLookupByName (conn, domname);

  if (dom) {
    domain_exists = 1;
    virDomainFree (dom);
  }
  else {
    err = virGetLastError ();
    if (err->code == VIR_ERR_NO_DOMAIN)
      domain_exists = 0;
    else {
      snprintf (errmsg, sizeof errmsg,
                _("cannot find libvirt domain '%s': %s"),
                domname, err->message);
      virConnectClose (conn);
      caml_invalid_argument (errmsg);
    }
  }

  virConnectClose (conn);

  CAMLreturn (Val_bool (domain_exists));
}

/* XXX This function is stuffed here for convenience (accessing
 * libvirt), not because it belongs logically with the rest of the
 * functions in this file.
 */
value
v2v_libvirt_get_version (value unitv)
{
  CAMLparam1 (unitv);
  CAMLlocal1 (rv);
  int major, minor, release;
  /* We have to assemble the error on the stack because a dynamic
   * string couldn't be freed.
   */
  char errmsg[ERROR_MESSAGE_LEN];
  unsigned long ver;
  virErrorPtr err;

  if (virGetVersion (&ver, NULL, NULL) == -1) {
    err = virGetLastError ();
    snprintf (errmsg, sizeof errmsg,
              _("cannot get libvirt library version: %s"),
              err->message);
    caml_invalid_argument (errmsg);
  }

  major = ver / 1000000UL;
  minor = ver / 1000UL % 1000UL;
  release = ver % 1000UL;

  rv = caml_alloc (3, 0);
  Store_field (rv, 0, Val_int (major));
  Store_field (rv, 1, Val_int (minor));
  Store_field (rv, 2, Val_int (release));

  CAMLreturn (rv);
}

#else /* !HAVE_LIBVIRT */

#define NO_LIBVIRT(proto)                                               \
  proto __attribute__((noreturn));                                      \
  proto                                                                 \
  {                                                                     \
    caml_invalid_argument ("virt-v2v was compiled without libvirt support"); \
  }

NO_LIBVIRT (value v2v_dumpxml (value connv, value domv))
NO_LIBVIRT (value v2v_pool_dumpxml (value connv, value poolv))
NO_LIBVIRT (value v2v_vol_dumpxml (value connv, value poolnamev, value volnamev))
NO_LIBVIRT (value v2v_capabilities (value connv, value unitv))
NO_LIBVIRT (value v2v_domain_exists (value connv, value domnamev))
NO_LIBVIRT (value v2v_libvirt_get_version (value unitv))

#endif /* !HAVE_LIBVIRT */