path: root/src/handle.c

/* libguestfs
 * Copyright (C) 2009-2012 Red Hat Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <config.h>

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

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

#ifdef HAVE_LIBXML2
#include <libxml/parser.h>
#include <libxml/xmlversion.h>
#endif

#include "glthread/lock.h"

#include "guestfs.h"
#include "guestfs-internal.h"
#include "guestfs-internal-actions.h"
#include "guestfs_protocol.h"

static int parse_attach_method (guestfs_h *g, const char *method);
static int shutdown_backend (guestfs_h *g, int check_for_errors);
static void close_handles (void);

gl_lock_define_initialized (static, handles_lock);
static guestfs_h *handles = NULL;
static int atexit_handler_set = 0;

gl_lock_define_initialized (static, init_lock);

/* No initialization is required by libguestfs, but libvirt and
 * libxml2 require initialization if they might be called from
 * multiple threads.  Hence this constructor function which is called
 * when libguestfs is first loaded.
 */
static void init_libguestfs (void) __attribute__((constructor));

static void
init_libguestfs (void)
{
#if defined(HAVE_LIBVIRT) || defined(HAVE_LIBXML2)
  gl_lock_lock (init_lock);
#endif
#ifdef HAVE_LIBVIRT
  virInitialize ();
#endif
#ifdef HAVE_LIBXML2
  xmlInitParser ();
  LIBXML_TEST_VERSION;
#endif
#if defined(HAVE_LIBVIRT) || defined(HAVE_LIBXML2)
  gl_lock_unlock (init_lock);
#endif
}

guestfs_h *
guestfs_create (void)
{
  return guestfs_create_flags (0);
}

guestfs_h *
guestfs_create_flags (unsigned flags, ...)
{
  guestfs_h *g;

  g = calloc (1, sizeof (*g));
  if (!g) return NULL;

  g->state = CONFIG;

  g->fd[0] = -1;
  g->fd[1] = -1;
  g->sock = -1;

  guestfs___init_error_handler (g);
  g->abort_cb = abort;

  g->recovery_proc = 1;
  g->autosync = 1;

  g->memsize = 500;

  /* Start with large serial numbers so they are easy to spot
   * inside the protocol.
   */
  g->msg_next_serial = 0x00123400;

  /* Default is uniprocessor appliance. */
  g->smp = 1;

  g->path = strdup (GUESTFS_DEFAULT_PATH);
  if (!g->path) goto error;

  g->qemu = strdup (QEMU);
  if (!g->qemu) goto error;

  if (parse_attach_method (g, DEFAULT_ATTACH_METHOD) == -1) {
    warning (g, _("libguestfs was built with an invalid default attach-method, using 'appliance' instead"));
    g->attach_method = ATTACH_METHOD_APPLIANCE;
  }

  if (!(flags & GUESTFS_CREATE_NO_ENVIRONMENT))
    guestfs_parse_environment (g);

  if (!(flags & GUESTFS_CREATE_NO_CLOSE_ON_EXIT)) {
    g->close_on_exit = true;

    /* Link the handles onto a global list. */
    gl_lock_lock (handles_lock);
    g->next = handles;
    handles = g;
    if (!atexit_handler_set) {
      atexit (close_handles);
      atexit_handler_set = 1;
    }
    gl_lock_unlock (handles_lock);
  }

  debug (g, "create: flags = %u, handle = %p", flags, g);

  return g;

 error:
  free (g->attach_method_arg);
  free (g->path);
  free (g->qemu);
  free (g->append);
  free (g);
  return NULL;
}

static int
parse_environment (guestfs_h *g,
                   char *(*do_getenv) (const void *data, const char *),
                   const void *data)
{
  int memsize;
  char *str;

  /* Don't bother checking the return values of functions
   * that cannot return errors.
   */

  str = do_getenv (data, "LIBGUESTFS_TRACE");
  if (str != NULL && STREQ (str, "1"))
    guestfs_set_trace (g, 1);

  str = do_getenv (data, "LIBGUESTFS_DEBUG");
  if (str != NULL && STREQ (str, "1"))
    guestfs_set_verbose (g, 1);

  str = do_getenv (data, "LIBGUESTFS_TMPDIR");
  if (str)
    guestfs_set_tmpdir (g, str);

  str = do_getenv (data, "LIBGUESTFS_CACHEDIR");
  if (str)
    guestfs_set_cachedir (g, str);

  free (g->env_tmpdir);
  str = do_getenv (data, "TMPDIR");
  g->env_tmpdir = str ? safe_strdup (g, str) : NULL;

  str = do_getenv (data, "LIBGUESTFS_PATH");
  if (str)
    guestfs_set_path (g, str);

  str = do_getenv (data, "LIBGUESTFS_QEMU");
  if (str)
    guestfs_set_qemu (g, str);

  str = do_getenv (data, "LIBGUESTFS_APPEND");
  if (str)
    guestfs_set_append (g, str);

  str = do_getenv (data, "LIBGUESTFS_MEMSIZE");
  if (str) {
    if (sscanf (str, "%d", &memsize) != 1 || memsize < 128) {
      error (g, "non-numeric or too small value for LIBGUESTFS_MEMSIZE");
      return -1;
    }
    guestfs_set_memsize (g, memsize);
  }

  str = do_getenv (data, "LIBGUESTFS_ATTACH_METHOD");
  if (str) {
    if (guestfs_set_attach_method (g, str) == -1)
      return -1;
  }

  return 0;
}

static char *
call_getenv (const void *data, const char *name)
{
  return getenv (name);
}

int
guestfs__parse_environment (guestfs_h *g)
{
  return parse_environment (g, call_getenv, NULL);
}

static char *
getenv_from_strings (const void *stringsv, const char *name)
{
  char **strings = (char **) stringsv;
  size_t len = strlen (name);
  size_t i;

  for (i = 0; strings[i] != NULL; ++i)
    if (STRPREFIX (strings[i], name) && strings[i][len] == '=')
      return (char *) &strings[i][len+1];
  return NULL;
}

int
guestfs__parse_environment_list (guestfs_h *g, char * const *strings)
{
  return parse_environment (g, getenv_from_strings, strings);
}

void
guestfs_close (guestfs_h *g)
{
  struct qemu_param *qp, *qp_next;
  guestfs_h **gg;

  if (g->state == NO_HANDLE) {
    /* Not safe to call ANY callbacks here, so ... */
    fprintf (stderr, _("guestfs_close: called twice on the same handle\n"));
    return;
  }

  /* Remove the handle from the handles list. */
  if (g->close_on_exit) {
    gl_lock_lock (handles_lock);
    for (gg = &handles; *gg != g; gg = &(*gg)->next)
      ;
    *gg = g->next;
    gl_lock_unlock (handles_lock);
  }

  if (g->trace) {
    const char trace_msg[] = "close";

    guestfs___call_callbacks_message (g, GUESTFS_EVENT_TRACE,
                                      trace_msg, strlen (trace_msg));
  }

  debug (g, "closing guestfs handle %p (state %d)", g, g->state);

  /* If we are valgrinding the daemon, then we *don't* want to kill
   * the subprocess because we want the final valgrind messages sent
   * when we close sockets below.  However for normal production use,
   * killing the subprocess is the right thing to do (in case the
   * daemon or qemu is not responding).
   */
#ifndef VALGRIND_DAEMON
  if (g->state != CONFIG)
    shutdown_backend (g, 0);
#endif

  /* Run user close callbacks. */
  guestfs___call_callbacks_void (g, GUESTFS_EVENT_CLOSE);

  /* Test output file used by bindtests. */
  if (g->test_fp != NULL)
    fclose (g->test_fp);

  /* Remove temporary directory. */
  guestfs___remove_tmpdir (g);

  /* Mark the handle as dead and then free up all memory. */
  g->state = NO_HANDLE;

  free (g->events);
  g->nr_events = 0;
  g->events = NULL;

#if HAVE_FUSE
  guestfs___free_fuse (g);
#endif

  guestfs___free_inspect_info (g);
  guestfs___free_drives (g);

  for (qp = g->qemu_params; qp; qp = qp_next) {
    free (qp->qemu_param);
    free (qp->qemu_value);
    qp_next = qp->next;
    free (qp);
  }

  while (g->error_cb_stack)
    guestfs_pop_error_handler (g);

  if (g->pda)
    hash_free (g->pda);
  free (g->tmpdir);
  free (g->env_tmpdir);
  free (g->int_tmpdir);
  free (g->int_cachedir);
  free (g->last_error);
  free (g->path);
  free (g->qemu);
  free (g->append);
  free (g);
}

int
guestfs__shutdown (guestfs_h *g)
{
  return shutdown_backend (g, 1);
}

/* guestfs_shutdown calls shutdown_backend with check_for_errors = 1.
 * guestfs_close calls shutdown_backend with check_for_errors = 0.
 *
 * 'check_for_errors' is a hint to the backend about whether we care
 * about errors or not.  In the libvirt case it can be used to
 * optimize the shutdown for speed when we don't care.
 */
static int
shutdown_backend (guestfs_h *g, int check_for_errors)
{
  int ret = 0;

  if (g->state == CONFIG)
    return 0;

  /* Try to sync if autosync flag is set. */
  if (g->autosync && g->state == READY) {
    if (guestfs_internal_autosync (g) == -1)
      ret = -1;
  }

  /* Close sockets. */
  if (g->fd[0] >= 0)
    close (g->fd[0]);
  if (g->fd[1] >= 0)
    close (g->fd[1]);
  if (g->sock >= 0)
    close (g->sock);
  g->fd[0] = -1;
  g->fd[1] = -1;
  g->sock = -1;

  if (g->attach_ops->shutdown (g, check_for_errors) == -1)
    ret = -1;

  guestfs___free_drives (g);

  g->state = CONFIG;

  return ret;
}

/* Close all open handles (called from atexit(3)). */
static void
close_handles (void)
{
  while (handles) guestfs_close (handles);
}

void
guestfs_user_cancel (guestfs_h *g)
{
  g->user_cancel = 1;
}

int
guestfs__set_verbose (guestfs_h *g, int v)
{
  g->verbose = !!v;
  return 0;
}

int
guestfs__get_verbose (guestfs_h *g)
{
  return g->verbose;
}

int
guestfs__set_autosync (guestfs_h *g, int a)
{
  g->autosync = !!a;
  return 0;
}

int
guestfs__get_autosync (guestfs_h *g)
{
  return g->autosync;
}

int
guestfs__set_path (guestfs_h *g, const char *path)
{
  free (g->path);
  g->path = NULL;

  g->path =
    path == NULL ?
    safe_strdup (g, GUESTFS_DEFAULT_PATH) : safe_strdup (g, path);
  return 0;
}

const char *
guestfs__get_path (guestfs_h *g)
{
  return g->path;
}

int
guestfs__set_qemu (guestfs_h *g, const char *qemu)
{
  free (g->qemu);
  g->qemu = NULL;

  g->qemu = qemu == NULL ? safe_strdup (g, QEMU) : safe_strdup (g, qemu);
  return 0;
}

const char *
guestfs__get_qemu (guestfs_h *g)
{
  return g->qemu;
}

int
guestfs__set_append (guestfs_h *g, const char *append)
{
  free (g->append);
  g->append = NULL;

  g->append = append ? safe_strdup (g, append) : NULL;
  return 0;
}

const char *
guestfs__get_append (guestfs_h *g)
{
  return g->append;
}

int
guestfs__set_memsize (guestfs_h *g, int memsize)
{
  g->memsize = memsize;
  return 0;
}

int
guestfs__get_memsize (guestfs_h *g)
{
  return g->memsize;
}

int
guestfs__set_selinux (guestfs_h *g, int selinux)
{
  g->selinux = selinux;
  return 0;
}

int
guestfs__get_selinux (guestfs_h *g)
{
  return g->selinux;
}

struct guestfs_version *
guestfs__version (guestfs_h *g)
{
  struct guestfs_version *r;

  r = safe_malloc (g, sizeof *r);
  r->major = PACKAGE_VERSION_MAJOR;
  r->minor = PACKAGE_VERSION_MINOR;
  r->release = PACKAGE_VERSION_RELEASE;
  r->extra = safe_strdup (g, PACKAGE_VERSION_EXTRA);
  return r;
}

int
guestfs__set_trace (guestfs_h *g, int t)
{
  g->trace = !!t;
  return 0;
}

int
guestfs__get_trace (guestfs_h *g)
{
  return g->trace;
}

int
guestfs__set_direct (guestfs_h *g, int d)
{
  g->direct = !!d;
  return 0;
}

int
guestfs__get_direct (guestfs_h *g)
{
  return g->direct;
}

int
guestfs__set_recovery_proc (guestfs_h *g, int f)
{
  g->recovery_proc = !!f;
  return 0;
}

int
guestfs__get_recovery_proc (guestfs_h *g)
{
  return g->recovery_proc;
}

int
guestfs__set_network (guestfs_h *g, int v)
{
  g->enable_network = !!v;
  return 0;
}

int
guestfs__get_network (guestfs_h *g)
{
  return g->enable_network;
}

static int
parse_attach_method (guestfs_h *g, const char *method)
{
  if (STREQ (method, "appliance")) {
    g->attach_method = ATTACH_METHOD_APPLIANCE;
    free (g->attach_method_arg);
    g->attach_method_arg = NULL;
    return 0;
  }

  if (STREQ (method, "libvirt")) {
    g->attach_method = ATTACH_METHOD_LIBVIRT;
    free (g->attach_method_arg);
    g->attach_method_arg = NULL;
    return 0;
  }

  if (STRPREFIX (method, "libvirt:") && strlen (method) > 8) {
    g->attach_method = ATTACH_METHOD_LIBVIRT;
    free (g->attach_method_arg);
    g->attach_method_arg = safe_strdup (g, method + 8);
    return 0;
  }

  if (STRPREFIX (method, "unix:") && strlen (method) > 5) {
    g->attach_method = ATTACH_METHOD_UNIX;
    free (g->attach_method_arg);
    g->attach_method_arg = safe_strdup (g, method + 5);
    /* Note that we don't check the path exists until launch is called. */
    return 0;
  }

  return -1;
}

int
guestfs__set_attach_method (guestfs_h *g, const char *method)
{
  if (parse_attach_method (g, method) == -1) {
    error (g, "invalid attach method: %s", method);
    return -1;
  }

  return 0;
}

char *
guestfs__get_attach_method (guestfs_h *g)
{
  char *ret;

  switch (g->attach_method) {
  case ATTACH_METHOD_APPLIANCE:
    ret = safe_strdup (g, "appliance");
    break;

  case ATTACH_METHOD_LIBVIRT:
    if (g->attach_method_arg == NULL)
      ret = safe_strdup (g, "libvirt");
    else
      ret = safe_asprintf (g, "libvirt:%s", g->attach_method_arg);
    break;

  case ATTACH_METHOD_UNIX:
    ret = safe_asprintf (g, "unix:%s", g->attach_method_arg);
    break;

  default: /* keep GCC happy - this is not reached */
    abort ();
  }

  return ret;
}

int
guestfs__set_pgroup (guestfs_h *g, int v)
{
  g->pgroup = !!v;
  return 0;
}

int
guestfs__get_pgroup (guestfs_h *g)
{
  return g->pgroup;
}

int
guestfs__set_smp (guestfs_h *g, int v)
{
  if (v > 255) {
    error (g, "unsupported number of smp vcpus: %d", v);
    return -1;
  } else if (v >= 1) {
    g->smp = v;
    return 0;
  } else {
    error (g, "invalid smp parameter: %d", v);
    return -1;
  }
}

int
guestfs__get_smp (guestfs_h *g)
{
  return g->smp;
}