check_fstab (guestfs_h *g, struct inspect_fs *fs)
{
  CLEANUP_FREE_STRING_LIST char **entries = NULL;
  char **entry;
  char augpath[256];
  CLEANUP_HASH_FREE Hash_table *md_map;

  /* Generate a map of MD device paths listed in /etc/mdadm.conf to MD device
   * paths in the guestfs appliance */
  if (map_md_devices (g, &md_map) == -1) return -1;

  entries = guestfs_aug_match (g, "/files/etc/fstab/*[label() != '#comment']");
  if (entries == NULL)
    return -1;

  if (entries[0] == NULL) {
    error (g, _("could not parse /etc/fstab or empty file"));
    return -1;
  }

  for (entry = entries; *entry != NULL; entry++) {
    snprintf (augpath, sizeof augpath, "%s/spec", *entry);
    CLEANUP_FREE char *spec = guestfs_aug_get (g, augpath);
    if (spec == NULL)
      return -1;

    /* Ignore /dev/fd (floppy disks) (RHBZ#642929) and CD-ROM drives. */
    if ((STRPREFIX (spec, "/dev/fd") && c_isdigit (spec[7])) ||
        STREQ (spec, "/dev/floppy") ||
        STREQ (spec, "/dev/cdrom"))
      continue;

    snprintf (augpath, sizeof augpath, "%s/file", *entry);
    CLEANUP_FREE char *mp = guestfs_aug_get (g, augpath);
    if (mp == NULL)
      return -1;

    /* Ignore certain mountpoints. */
    if (STRPREFIX (mp, "/dev/") ||
        STREQ (mp, "/dev") ||
        STRPREFIX (mp, "/media/") ||
        STRPREFIX (mp, "/proc/") ||
        STREQ (mp, "/proc") ||
        STRPREFIX (mp, "/selinux/") ||
        STREQ (mp, "/selinux") ||
        STRPREFIX (mp, "/sys/") ||
        STREQ (mp, "/sys"))
      continue;

    /* Resolve UUID= and LABEL= to the actual device. */
    CLEANUP_FREE char *mountable = NULL;
    if (STRPREFIX (spec, "UUID="))
      mountable = guestfs_findfs_uuid (g, &spec[5]);
    else if (STRPREFIX (spec, "LABEL="))
      mountable = guestfs_findfs_label (g, &spec[6]);
    /* Ignore "/.swap" (Pardus) and pseudo-devices like "tmpfs". */
    else if (STREQ (spec, "/dev/root"))
      /* Resolve /dev/root to the current device. */
      mountable = safe_strdup (g, fs->mountable);
    else if (STRPREFIX (spec, "/dev/"))
      /* Resolve guest block device names. */
      mountable = resolve_fstab_device (g, spec, md_map);

    /* If we haven't resolved the device successfully by this point,
     * we don't care, just ignore it.
     */
    if (mountable == NULL)
      continue;

    snprintf (augpath, sizeof augpath, "%s/vfstype", *entry);
    CLEANUP_FREE char *vfstype = guestfs_aug_get (g, augpath);
    if (vfstype == NULL) return -1;

    if (STREQ (vfstype, "btrfs")) {
      snprintf (augpath, sizeof augpath, "%s/opt", *entry);
      CLEANUP_FREE_STRING_LIST char **opts = guestfs_aug_match (g, augpath);
      if (opts == NULL) return -1;

      for (char **opt = opts; *opt; opt++) {
        CLEANUP_FREE char *optname = guestfs_aug_get (g, augpath);
        if (optname == NULL) return -1;

        if (STREQ (optname, "subvol")) {
          snprintf (augpath, sizeof augpath, "%s/value", *opt);
          CLEANUP_FREE char *subvol = guestfs_aug_get (g, augpath);
          if (subvol == NULL) return -1;

          char *new = safe_asprintf (g, "btrfsvol:%s/%s", mountable, subvol);
          free (mountable);
          mountable = new;
        }
      }
    }

    if  (add_fstab_entry (g, fs, mountable, mp) == -1) return -1;
  }

  return 0;
}


mdadm_app_free(void *x)
{
  mdadm_app *a = x;
  free(a->mdadm);
  free(a->app);
  free(a);
}

inspection: Don't segfault if /etc/SuSE-release is an empty file.

Related to CVE-2013-2124.

Thanks: Olaf Hering.


resolve_fstab_device (guestfs_h *g, const char *spec, Hash_table *md_map)
{
  char *device = NULL;
  char *type, *slice, *disk, *part;
  int r;

  if (STRPREFIX (spec, "/dev/mapper/") && guestfs_exists (g, spec) > 0) {
    /* LVM2 does some strange munging on /dev/mapper paths for VGs and
     * LVs which contain '-' character:
     *
     * ><fs> lvcreate LV--test VG--test 32
     * ><fs> debug ls /dev/mapper
     * VG----test-LV----test
     *
     * This makes it impossible to reverse those paths directly, so
     * we have implemented lvm_canonical_lv_name in the daemon.
     */
    device = guestfs_lvm_canonical_lv_name (g, spec);
  }
  else if (match3 (g, spec, re_xdev, &type, &disk, &part)) {
    r = resolve_fstab_device_xdev (g, type, disk, part, &device);
    free (type);
    free (disk);
    free (part);
    if (r == -1)
      return NULL;
  }
  else if (match2 (g, spec, re_cciss, &disk, &part)) {
    r = resolve_fstab_device_cciss (g, disk, part, &device);
    free (disk);
    free (part);
    if (r == -1)
      return NULL;
  }
  else if (md_map && (disk = match1 (g, spec, re_mdN)) != NULL) {
    mdadm_app entry;
    entry.mdadm = disk;

    mdadm_app *app = hash_lookup (md_map, &entry);
    if (app) device = safe_strdup (g, app->app);

    free (disk);
  }
  else if (match3 (g, spec, re_freebsd, &disk, &slice, &part)) {
    /* FreeBSD disks are organized quite differently.  See:
     * http://www.freebsd.org/doc/handbook/disk-organization.html
     * FreeBSD "partitions" are exposed as quasi-extended partitions
     * numbered from 5 in Linux.  I have no idea what happens when you
     * have multiple "slices" (the FreeBSD term for MBR partitions).
     */
    int disk_i = guestfs___parse_unsigned_int (g, disk);
    int slice_i = guestfs___parse_unsigned_int (g, slice);
    int part_i = part[0] - 'a' /* counting from 0 */;
    free (disk);
    free (slice);
    free (part);

    if (disk_i != -1 && disk_i <= 26 &&
        slice_i > 0 && slice_i <= 1 /* > 4 .. see comment above */ &&
        part_i >= 0 && part_i < 26) {
      device = safe_asprintf (g, "/dev/sd%c%d", disk_i + 'a', part_i + 5);
    }
  }
  else if ((part = match1 (g, spec, re_diskbyid)) != NULL) {
    r = resolve_fstab_device_diskbyid (g, part, &device);
    free (part);
    if (r == -1)
      return NULL;
  }

  /* Didn't match device pattern, return original spec unchanged. */
  if (device == NULL)
    device = safe_strdup (g, spec);

  return device;
}


compile_regexps (void)
{
  const char *err;
  int offset;

#define COMPILE(re,pattern,options)                                     \
  do {                                                                  \
    re = pcre_compile ((pattern), (options), &err, &offset, NULL);      \
    if (re == NULL) {                                                   \
      ignore_value (write (2, err, strlen (err)));                      \
      abort ();                                                         \
    }                                                                   \
  } while (0)

  COMPILE (re_fedora, "Fedora release (\\d+)", 0);
  COMPILE (re_rhel_old,
           "Red Hat.*release (\\d+).*Update (\\d+)", 0);
  COMPILE (re_rhel,
           "Red Hat.*release (\\d+)\\.(\\d+)", 0);
  COMPILE (re_rhel_no_minor,
           "Red Hat.*release (\\d+)", 0);
  COMPILE (re_centos_old,
           "CentOS.*release (\\d+).*Update (\\d+)", 0);
  COMPILE (re_centos,
           "CentOS.*release (\\d+)\\.(\\d+)", 0);
  COMPILE (re_centos_no_minor,
           "CentOS.*release (\\d+)", 0);
  COMPILE (re_scientific_linux_old,
           "Scientific Linux.*release (\\d+).*Update (\\d+)", 0);
  COMPILE (re_scientific_linux,
           "Scientific Linux.*release (\\d+)\\.(\\d+)", 0);
  COMPILE (re_scientific_linux_no_minor,
           "Scientific Linux.*release (\\d+)", 0);
  COMPILE (re_major_minor, "(\\d+)\\.(\\d+)", 0);
  COMPILE (re_xdev, "^/dev/(h|s|v|xv)d([a-z]+)(\\d*)$", 0);
  COMPILE (re_cciss, "^/dev/(cciss/c\\d+d\\d+)(?:p(\\d+))?$", 0);
  COMPILE (re_mdN, "^(/dev/md\\d+)$", 0);
  COMPILE (re_freebsd, "^/dev/ad(\\d+)s(\\d+)([a-z])$", 0);
  COMPILE (re_diskbyid, "^/dev/disk/by-id/.*-part(\\d+)$", 0);
  COMPILE (re_netbsd, "^NetBSD (\\d+)\\.(\\d+)", 0);
  COMPILE (re_opensuse, "^(openSUSE|SuSE Linux|SUSE LINUX) ", 0);
  COMPILE (re_sles, "^SUSE (Linux|LINUX) Enterprise ", 0);
  COMPILE (re_nld, "^Novell Linux Desktop ", 0);
  COMPILE (re_opensuse_version, "^VERSION = (\\d+)\\.(\\d+)", 0);
  COMPILE (re_sles_version, "^VERSION = (\\d+)", 0);
  COMPILE (re_sles_patchlevel, "^PATCHLEVEL = (\\d+)", 0);
}


uuid_hash(const void *x, size_t table_size)
{
  const md_uuid *a = x;

  size_t h = a->uuid[0];
  for (size_t i = 1; i < 4; i++) {
    h ^= a->uuid[i];
  }

  return h % table_size;
}


is_partition (guestfs_h *g, const char *partition)
{
  CLEANUP_FREE char *device = NULL;

  guestfs_push_error_handler (g, NULL, NULL);

  if ((device = guestfs_part_to_dev (g, partition)) == NULL) {
    guestfs_pop_error_handler (g);
    return 0;
  }

  if (guestfs_device_index (g, device) == -1) {
    guestfs_pop_error_handler (g);
    return 0;
  }

  guestfs_pop_error_handler (g);

  return 1;
}


check_hostname_freebsd (guestfs_h *g, struct inspect_fs *fs)
{
  const char *filename = "/etc/rc.conf";
  int64_t size;
  CLEANUP_FREE_STRING_LIST char **lines = NULL;
  size_t i;

  /* Don't trust guestfs_read_lines not to break with very large files.
   * Check the file size is something reasonable first.
   */
  size = guestfs_filesize (g, filename);
  if (size == -1)
    /* guestfs_filesize failed and has already set error in handle */
    return -1;
  if (size > MAX_SMALL_FILE_SIZE) {
    error (g, _("size of %s is unreasonably large (%" PRIi64 " bytes)"),
           filename, size);
    return -1;
  }

  lines = guestfs_read_lines (g, filename);
  if (lines == NULL)
    return -1;

  for (i = 0; lines[i] != NULL; ++i) {
    if (STRPREFIX (lines[i], "hostname=\"") ||
        STRPREFIX (lines[i], "hostname='")) {
      size_t len = strlen (lines[i]) - 10 - 1;
      fs->hostname = safe_strndup (g, &lines[i][10], len);
      break;
    } else if (STRPREFIX (lines[i], "hostname=")) {
      size_t len = strlen (lines[i]) - 9;
      fs->hostname = safe_strndup (g, &lines[i][9], len);
      break;
    }
  }

  return 0;
}


check_hostname_unix (guestfs_h *g, struct inspect_fs *fs)
{
  switch (fs->type) {
  case OS_TYPE_LINUX:
  case OS_TYPE_HURD:
    /* Red Hat-derived would be in /etc/sysconfig/network or
     * /etc/hostname (RHEL 7+, F18+).  Debian-derived in the file
     * /etc/hostname.  Very old Debian and SUSE use /etc/HOSTNAME.
     * It's best to just look for each of these files in turn, rather
     * than try anything clever based on distro.
     */
    if (guestfs_is_file (g, "/etc/HOSTNAME")) {
      fs->hostname = guestfs___first_line_of_file (g, "/etc/HOSTNAME");
      if (fs->hostname == NULL)
        return -1;
      if (STREQ (fs->hostname, "")) {
        free (fs->hostname);
        fs->hostname = NULL;
      }
    }

    if (!fs->hostname && guestfs_is_file (g, "/etc/hostname")) {
      fs->hostname = guestfs___first_line_of_file (g, "/etc/hostname");
      if (fs->hostname == NULL)
        return -1;
      if (STREQ (fs->hostname, "")) {
        free (fs->hostname);
        fs->hostname = NULL;
      }
    }

    if (!fs->hostname && guestfs_is_file (g, "/etc/sysconfig/network")) {
      const char *configfiles[] = { "/etc/sysconfig/network", NULL };
      if (inspect_with_augeas (g, fs, configfiles,
                               check_hostname_redhat) == -1)
        return -1;
    }
    break;

  case OS_TYPE_FREEBSD:
  case OS_TYPE_NETBSD:
    /* /etc/rc.conf contains the hostname, but there is no Augeas lens
     * for this file.
     */
    if (guestfs_is_file (g, "/etc/rc.conf")) {
      if (check_hostname_freebsd (g, fs) == -1)
        return -1;
    }
    break;

  case OS_TYPE_WINDOWS: /* not here, see check_windows_system_registry */
  case OS_TYPE_DOS:
  case OS_TYPE_OPENBSD:
  case OS_TYPE_UNKNOWN:
    /* nothing */;
  }

  return 0;
}


parse_uuid (const char *str, uint32_t *uuid)
{
  size_t hit = 0; /* number of Hex digIT */
  char c;
  size_t i;
  int n;

  for (i = 0; i < 4; i++)
    uuid[i] = 0;

  while ((c = *str++)) {
    if (c >= '0' && c <= '9')
      n = c - '0';
    else if (c >= 'a' && c <= 'f')
      n = 10 + c - 'a';
    else if (c >= 'A' && c <= 'F')
      n = 10 + c - 'A';
    else if (strchr (":. -", c))
      continue;
    else
      return -1;

    if (hit < 32) {
      uuid[hit / 8] <<= 4;
      uuid[hit / 8] += n;
    }
    hit++;
  }
  if (hit == 32) return 0;

  return -1;
}


guestfs___check_netbsd_root (guestfs_h *g, struct inspect_fs *fs)
{

  if (guestfs_exists (g, "/etc/release") > 0) {
    char *major, *minor;
    if (parse_release_file (g, fs, "/etc/release") == -1)
      return -1;

    if (match2 (g, fs->product_name, re_netbsd, &major, &minor)) {
      fs->type = OS_TYPE_NETBSD;
      fs->major_version = guestfs___parse_unsigned_int (g, major);
      free (major);
      if (fs->major_version == -1) {
        free (minor);
        return -1;
      }
      fs->minor_version = guestfs___parse_unsigned_int (g, minor);
      free (minor);
      if (fs->minor_version == -1)
        return -1;
    }
  } else {
    return -1;
  }

  /* Determine the architecture. */
  check_architecture (g, fs);

  /* We already know /etc/fstab exists because it's part of the test above. */
  const char *configfiles[] = { "/etc/fstab", NULL };
  if (inspect_with_augeas (g, fs, configfiles, check_fstab) == -1)
    return -1;

  /* Determine hostname. */
  if (check_hostname_unix (g, fs) == -1)
    return -1;

  return 0;
}


check_architecture (guestfs_h *g, struct inspect_fs *fs)
{
  const char *binaries[] =
    { "/bin/bash", "/bin/ls", "/bin/echo", "/bin/rm", "/bin/sh" };
  size_t i;
  char *arch;

  for (i = 0; i < sizeof binaries / sizeof binaries[0]; ++i) {
    if (guestfs_is_file (g, binaries[i]) > 0) {
      /* Ignore errors from file_architecture call. */
      guestfs_push_error_handler (g, NULL, NULL);
      arch = guestfs_file_architecture (g, binaries[i]);
      guestfs_pop_error_handler (g);

      if (arch) {
        /* String will be owned by handle, freed by
         * guestfs___free_inspect_info.
         */
        fs->arch = arch;
        break;
      }
    }
  }
}


add_fstab_entry (guestfs_h *g, struct inspect_fs *fs,
                 const char *mountable, const char *mountpoint)
{
  /* Add this to the fstab entry in 'fs'.
   * Note these are further filtered by guestfs_inspect_get_mountpoints
   * and guestfs_inspect_get_filesystems.
   */
  size_t n = fs->nr_fstab + 1;
  struct inspect_fstab_entry *p;

  p = realloc (fs->fstab, n * sizeof (struct inspect_fstab_entry));
  if (p == NULL) {
    perrorf (g, "realloc");
    return -1;
  }

  fs->fstab = p;
  fs->nr_fstab = n;

  /* These are owned by the handle and freed by guestfs___free_inspect_info. */
  fs->fstab[n-1].mountable = safe_strdup (g, mountable);
  fs->fstab[n-1].mountpoint = safe_strdup (g, mountpoint);

  debug (g, "fstab: mountable=%s mountpoint=%s", mountable, mountpoint);

  return 0;
}


mdadm_app_hash(const void *x, size_t table_size)
{
  const mdadm_app *a = x;
  return hash_pjw(a->mdadm, table_size);
}


map_md_devices(guestfs_h *g, Hash_table **map)
{
  CLEANUP_HASH_FREE Hash_table *app_map = NULL;
  CLEANUP_FREE_STRING_LIST char **matches = NULL;
  ssize_t n_app_md_devices;

  *map = NULL;

  /* Get a map of md device uuids to their device names in the appliance */
  n_app_md_devices = map_app_md_devices (g, &app_map);
  if (n_app_md_devices == -1) goto error;

  /* Nothing to do if there are no md devices */
  if (n_app_md_devices == 0)
    return 0;

  /* Get all arrays listed in mdadm.conf */
  matches = guestfs_aug_match(g, "/files/etc/mdadm.conf/array");
  if (!matches) goto error;

  /* Log a debug message if we've got md devices, but nothing in mdadm.conf */
  if (matches[0] == NULL) {
    debug(g, "Appliance has MD devices, but augeas returned no array matches "
             "in mdadm.conf");
    return 0;
  }

  *map = hash_initialize(16, NULL, mdadm_app_hash, mdadm_app_cmp,
                                   mdadm_app_free);
  if (!*map) g->abort_cb();

  for (char **m = matches; *m != NULL; m++) {
    /* Get device name and uuid for each array */
    CLEANUP_FREE char *dev_path = safe_asprintf (g, "%s/devicename", *m);
    char *dev = guestfs_aug_get (g, dev_path);
    if (!dev) goto error;

    CLEANUP_FREE char *uuid_path = safe_asprintf (g, "%s/uuid", *m);
    CLEANUP_FREE char *uuid = guestfs_aug_get (g, uuid_path);
    if (!uuid) {
      free (dev);
      continue;
    }

    /* Parse the uuid into an md_uuid structure so we can look it up in the
     * uuid->appliance device map */
    md_uuid mdadm;
    mdadm.path = dev;
    if (parse_uuid(uuid, mdadm.uuid) == -1) {
      /* Invalid uuid. Weird, but not fatal. */
      debug(g, "inspect-os: mdadm.conf contains invalid uuid for %s: %s",
            dev, uuid);
      free (dev);
      continue;
    }

    /* If there's a corresponding uuid in the appliance, create a new
     * entry in the transitive map */
    md_uuid *app = hash_lookup(app_map, &mdadm);
    if (app) {
      mdadm_app *entry = safe_malloc(g, sizeof(mdadm_app));
      entry->mdadm = dev;
      entry->app = safe_strdup(g, app->path);

      switch (hash_insert_if_absent(*map, entry, NULL)) {
        case -1:
          g->abort_cb();

        case 0:
          /* Duplicate uuid in for md device is weird, but not fatal. */
          debug(g, "inspect-os: mdadm.conf contains multiple entries for %s",
                app->path);
          mdadm_app_free(entry);
          continue;
      }
    } else
      free (dev);
  }

  return 0;

error:
  if (*map) hash_free (*map);

  return -1;
}


md_uuid_free(void *x)
{
  md_uuid *a = x;
  free(a->path);
  free(a);
}


parse_release_file (guestfs_h *g, struct inspect_fs *fs,
                    const char *release_filename)
{
  fs->product_name = guestfs___first_line_of_file (g, release_filename);
  if (fs->product_name == NULL)
    return -1;
  if (STREQ (fs->product_name, "")) {
    free (fs->product_name);
    fs->product_name = NULL;
    error (g, _("release file %s is empty or malformed"), release_filename);
    return -1;
  }
  return 0;
}


uuid_cmp(const void *x, const void *y)
{
  const md_uuid *a = x;
  const md_uuid *b = y;

  for (size_t i = 0; i < 1; i++) {
    if (a->uuid[i] != b->uuid[i]) return 0;
  }

  return 1;
}


guestfs___check_linux_root (guestfs_h *g, struct inspect_fs *fs)
{
  int r;

  fs->type = OS_TYPE_LINUX;

  if (guestfs_exists (g, "/etc/lsb-release") > 0) {
    r = parse_lsb_release (g, fs);
    if (r == -1)        /* error */
      return -1;
    if (r == 1)         /* ok - detected the release from this file */
      goto skip_release_checks;
  }

  if (guestfs_exists (g, "/etc/redhat-release") > 0) {
    fs->distro = OS_DISTRO_REDHAT_BASED; /* Something generic Red Hat-like. */

    if (parse_release_file (g, fs, "/etc/redhat-release") == -1)
      return -1;

    char *major, *minor;
    if ((major = match1 (g, fs->product_name, re_fedora)) != NULL) {
      fs->distro = OS_DISTRO_FEDORA;
      fs->major_version = guestfs___parse_unsigned_int (g, major);
      free (major);
      if (fs->major_version == -1)
        return -1;
    }
    else if (match2 (g, fs->product_name, re_rhel_old, &major, &minor) ||
             match2 (g, fs->product_name, re_rhel, &major, &minor)) {
      fs->distro = OS_DISTRO_RHEL;
      fs->major_version = guestfs___parse_unsigned_int (g, major);
      free (major);
      if (fs->major_version == -1) {
        free (minor);
        return -1;
      }
      fs->minor_version = guestfs___parse_unsigned_int (g, minor);
      free (minor);
      if (fs->minor_version == -1)
        return -1;
    }
    else if ((major = match1 (g, fs->product_name, re_rhel_no_minor)) != NULL) {
      fs->distro = OS_DISTRO_RHEL;
      fs->major_version = guestfs___parse_unsigned_int (g, major);
      free (major);
      if (fs->major_version == -1)
        return -1;
      fs->minor_version = 0;
    }
    else if (match2 (g, fs->product_name, re_centos_old, &major, &minor) ||
             match2 (g, fs->product_name, re_centos, &major, &minor)) {
      fs->distro = OS_DISTRO_CENTOS;
      fs->major_version = guestfs___parse_unsigned_int (g, major);
      free (major);
      if (fs->major_version == -1) {
        free (minor);
        return -1;
      }
      fs->minor_version = guestfs___parse_unsigned_int (g, minor);
      free (minor);
      if (fs->minor_version == -1)
        return -1;
    }
    else if ((major = match1 (g, fs->product_name, re_centos_no_minor)) != NULL) {
      fs->distro = OS_DISTRO_CENTOS;
      fs->major_version = guestfs___parse_unsigned_int (g, major);
      free (major);
      if (fs->major_version == -1)
        return -1;
      fs->minor_version = 0;
    }
    else if (match2 (g, fs->product_name, re_scientific_linux_old, &major, &minor) ||
             match2 (g, fs->product_name, re_scientific_linux, &major, &minor)) {
      fs->distro = OS_DISTRO_SCIENTIFIC_LINUX;
      fs->major_version = guestfs___parse_unsigned_int (g, major);
      free (major);
      if (fs->major_version == -1) {
        free (minor);
        return -1;
      }
      fs->minor_version = guestfs___parse_unsigned_int (g, minor);
      free (minor);
      if (fs->minor_version == -1)
        return -1;
    }
    else if ((major = match1 (g, fs->product_name, re_scientific_linux_no_minor)) != NULL) {
      fs->distro = OS_DISTRO_SCIENTIFIC_LINUX;
      fs->major_version = guestfs___parse_unsigned_int (g, major);
      free (major);
      if (fs->major_version == -1)
        return -1;
      fs->minor_version = 0;
    }
  }
  else if (guestfs_exists (g, "/etc/debian_version") > 0) {
    fs->distro = OS_DISTRO_DEBIAN;

    if (parse_release_file (g, fs, "/etc/debian_version") == -1)
      return -1;

    if (guestfs___parse_major_minor (g, fs) == -1)
      return -1;
  }
  else if (guestfs_exists (g, "/etc/pardus-release") > 0) {
    fs->distro = OS_DISTRO_PARDUS;

    if (parse_release_file (g, fs, "/etc/pardus-release") == -1)
      return -1;

    if (guestfs___parse_major_minor (g, fs) == -1)
      return -1;
  }
  else if (guestfs_exists (g, "/etc/arch-release") > 0) {
    fs->distro = OS_DISTRO_ARCHLINUX;

    /* /etc/arch-release file is empty and I can't see a way to
     * determine the actual release or product string.
     */
  }
  else if (guestfs_exists (g, "/etc/gentoo-release") > 0) {
    fs->distro = OS_DISTRO_GENTOO;

    if (parse_release_file (g, fs, "/etc/gentoo-release") == -1)
      return -1;

    if (guestfs___parse_major_minor (g, fs) == -1)
      return -1;
  }
  else if (guestfs_exists (g, "/etc/meego-release") > 0) {
    fs->distro = OS_DISTRO_MEEGO;

    if (parse_release_file (g, fs, "/etc/meego-release") == -1)
      return -1;

    if (guestfs___parse_major_minor (g, fs) == -1)
      return -1;
  }
  else if (guestfs_exists (g, "/etc/slackware-version") > 0) {
    fs->distro = OS_DISTRO_SLACKWARE;

    if (parse_release_file (g, fs, "/etc/slackware-version") == -1)
      return -1;

    if (guestfs___parse_major_minor (g, fs) == -1)
      return -1;
  }
  else if (guestfs_exists (g, "/etc/ttylinux-target") > 0) {
    fs->distro = OS_DISTRO_TTYLINUX;

    if (parse_release_file (g, fs, "/etc/ttylinux-target") == -1)
      return -1;

    if (guestfs___parse_major_minor (g, fs) == -1)
      return -1;
  }
  else if (guestfs_exists (g, "/etc/SuSE-release") > 0) {
    fs->distro = OS_DISTRO_SUSE_BASED;

    if (parse_suse_release (g, fs, "/etc/SuSE-release") == -1)
      return -1;

  }
  /* Buildroot (http://buildroot.net) is an embedded Linux distro
   * toolkit.  It is used by specific distros such as Cirros.
   */
  else if (guestfs_exists (g, "/etc/br-version") > 0) {
    if (guestfs_exists (g, "/usr/share/cirros/logo") > 0)
      fs->distro = OS_DISTRO_CIRROS;
    else
      fs->distro = OS_DISTRO_BUILDROOT;

    /* /etc/br-version has the format YYYY.MM[-git/hg/svn release] */
    if (parse_release_file (g, fs, "/etc/br-version") == -1)
      return -1;

    if (guestfs___parse_major_minor (g, fs) == -1)
      return -1;
  }

 skip_release_checks:;

  /* Determine the architecture. */
  check_architecture (g, fs);

  /* We already know /etc/fstab exists because it's part of the test
   * for Linux root above.  We must now parse this file to determine
   * which filesystems are used by the operating system and how they
   * are mounted.
   */
  const char *configfiles[] = { "/etc/fstab", "/etc/mdadm.conf", NULL };
  if (inspect_with_augeas (g, fs, configfiles, check_fstab) == -1)
    return -1;

  /* Determine hostname. */
  if (check_hostname_unix (g, fs) == -1)
    return -1;

  return 0;
}


guestfs___check_freebsd_root (guestfs_h *g, struct inspect_fs *fs)
{
  fs->type = OS_TYPE_FREEBSD;

  /* FreeBSD has no authoritative version file.  The version number is
   * in /etc/motd, which the system administrator might edit, but
   * we'll use that anyway.
   */

  if (guestfs_exists (g, "/etc/motd") > 0) {
    if (parse_release_file (g, fs, "/etc/motd") == -1)
      return -1;

    if (guestfs___parse_major_minor (g, fs) == -1)
      return -1;
  }

  /* Determine the architecture. */
  check_architecture (g, fs);

  /* We already know /etc/fstab exists because it's part of the test above. */
  const char *configfiles[] = { "/etc/fstab", NULL };
  if (inspect_with_augeas (g, fs, configfiles, check_fstab) == -1)
    return -1;

  /* Determine hostname. */
  if (check_hostname_unix (g, fs) == -1)
    return -1;

  return 0;
}


parse_lsb_release (guestfs_h *g, struct inspect_fs *fs)
{
  const char *filename = "/etc/lsb-release";
  int64_t size;
  CLEANUP_FREE_STRING_LIST char **lines = NULL;
  size_t i;
  int r = 0;

  /* Don't trust guestfs_head_n not to break with very large files.
   * Check the file size is something reasonable first.
   */
  size = guestfs_filesize (g, filename);
  if (size == -1)
    /* guestfs_filesize failed and has already set error in handle */
    return -1;
  if (size > MAX_SMALL_FILE_SIZE) {
    error (g, _("size of %s is unreasonably large (%" PRIi64 " bytes)"),
           filename, size);
    return -1;
  }

  lines = guestfs_head_n (g, 10, filename);
  if (lines == NULL)
    return -1;

  for (i = 0; lines[i] != NULL; ++i) {
    if (fs->distro == 0 &&
        STREQ (lines[i], "DISTRIB_ID=Ubuntu")) {
      fs->distro = OS_DISTRO_UBUNTU;
      r = 1;
    }
    else if (fs->distro == 0 &&
             STREQ (lines[i], "DISTRIB_ID=LinuxMint")) {
      fs->distro = OS_DISTRO_LINUX_MINT;
      r = 1;
    }
    else if (fs->distro == 0 &&
             STREQ (lines[i], "DISTRIB_ID=MandrivaLinux")) {
      fs->distro = OS_DISTRO_MANDRIVA;
      r = 1;
    }
    else if (fs->distro == 0 &&
             STREQ (lines[i], "DISTRIB_ID=\"Mageia\"")) {
      fs->distro = OS_DISTRO_MAGEIA;
      r = 1;
    }
    else if (STRPREFIX (lines[i], "DISTRIB_RELEASE=")) {
      char *major, *minor;
      if (match2 (g, &lines[i][16], re_major_minor, &major, &minor)) {
        fs->major_version = guestfs___parse_unsigned_int (g, major);
        free (major);
        if (fs->major_version == -1) {
          free (minor);
          return -1;
        }
        fs->minor_version = guestfs___parse_unsigned_int (g, minor);
        free (minor);
        if (fs->minor_version == -1)
          return -1;
      }
    }
    else if (fs->product_name == NULL &&
             (STRPREFIX (lines[i], "DISTRIB_DESCRIPTION=\"") ||
              STRPREFIX (lines[i], "DISTRIB_DESCRIPTION='"))) {
      size_t len = strlen (lines[i]) - 21 - 1;
      fs->product_name = safe_strndup (g, &lines[i][21], len);
      r = 1;
    }
    else if (fs->product_name == NULL &&
             STRPREFIX (lines[i], "DISTRIB_DESCRIPTION=")) {
      size_t len = strlen (lines[i]) - 20;
      fs->product_name = safe_strndup (g, &lines[i][20], len);
      r = 1;
    }
  }

  /* The unnecessary construct in the next line is required to
   * workaround -Wstrict-overflow warning in gcc 4.5.1.
   */
  return r ? 1 : 0;
}


guestfs___check_hurd_root (guestfs_h *g, struct inspect_fs *fs)
{
  fs->type = OS_TYPE_HURD;

  if (guestfs_exists (g, "/etc/debian_version") > 0) {
    fs->distro = OS_DISTRO_DEBIAN;

    if (parse_release_file (g, fs, "/etc/debian_version") == -1)
      return -1;

    if (guestfs___parse_major_minor (g, fs) == -1)
      return -1;
  }

  /* Arch Hurd also exists, but inconveniently it doesn't have
   * the normal /etc/arch-release file.  XXX
   */

  /* Determine the architecture. */
  check_architecture (g, fs);

  /* XXX Check for /etc/fstab. */

  /* Determine hostname. */
  if (check_hostname_unix (g, fs) == -1)
    return -1;

  return 0;
}


resolve_fstab_device_diskbyid (guestfs_h *g, const char *part,
                               char **device_ret)
{
  int nr_devices;
  char *device;

  /* For /dev/disk/by-id there is a limit to what we can do because
   * original SCSI ID information has likely been lost.  This
   * heuristic will only work for guests that have a single block
   * device.
   *
   * So the main task here is to make sure the assumptions above are
   * true.
   *
   * XXX Use hints from virt-p2v if available.
   * See also: https://bugzilla.redhat.com/show_bug.cgi?id=836573#c3
   */

  nr_devices = guestfs_nr_devices (g);
  if (nr_devices == -1)
    return -1;

  /* If #devices isn't 1, give up trying to translate this fstab entry. */
  if (nr_devices != 1)
    return 0;

  /* Make the partition name and check it exists. */
  device = safe_asprintf (g, "/dev/sda%s", part);
  if (!is_partition (g, device)) {
    free (device);
    return 0;
  }

  *device_ret = device;
  return 0;
}


resolve_fstab_device_cciss (guestfs_h *g, const char *disk, const char *part,
                            char **device_ret)
{
  char *device;
  CLEANUP_FREE_STRING_LIST char **devices = NULL;
  size_t i;
  struct drive *drv;

  /* disk: (cciss/c\d+d\d+)
   * part: (\d+)?
   */

  devices = guestfs_list_devices (g);
  if (devices == NULL)
    return -1;

  /* Check any hints we were passed for a non-heuristic mapping */
  ITER_DRIVES (g, i, drv) {
    if (drv->name && STREQ (drv->name, disk)) {
      if (part) {
        device = safe_asprintf (g, "%s%s", devices[i], part);
        if (!is_partition (g, device)) {
          free (device);
          return 0;
        }
        *device_ret = device;
      }
      else
        *device_ret = safe_strdup (g, devices[i]);
      break;
    }
  }

  /* We don't try to guess mappings for cciss devices */
  return 0;
}


void __cleanup_sighand(struct sighand_struct *sighand)
{
	if (refcount_dec_and_test(&sighand->count)) {
		signalfd_cleanup(sighand);
		/*
		 * sighand_cachep is SLAB_TYPESAFE_BY_RCU so we can free it
		 * without an RCU grace period, see __lock_task_sighand().
		 */
		kmem_cache_free(sighand_cachep, sighand);
	}
}

fork: fix copy_process(CLONE_PARENT) race with the exiting ->real_parent

current->group_leader->exit_signal may change during copy_process() if
current->real_parent exits.

Move the assignment inside tasklist_lock to avoid the race.

Signed-off-by: Eddy Wu <eddy_wu@trendmicro.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>


static void set_max_threads(unsigned int max_threads_suggested)
{
	u64 threads;
	unsigned long nr_pages = totalram_pages();

	/*
	 * The number of threads shall be limited such that the thread
	 * structures may only consume a small part of the available memory.
	 */
	if (fls64(nr_pages) + fls64(PAGE_SIZE) > 64)
		threads = MAX_THREADS;
	else
		threads = div64_u64((u64) nr_pages * (u64) PAGE_SIZE,
				    (u64) THREAD_SIZE * 8UL);

	if (threads > max_threads_suggested)
		threads = max_threads_suggested;

	max_threads = clamp_t(u64, threads, MIN_THREADS, MAX_THREADS);
}


SYSCALL_DEFINE2(clone3, struct clone_args __user *, uargs, size_t, size)
{
	int err;

	struct kernel_clone_args kargs;
	pid_t set_tid[MAX_PID_NS_LEVEL];

	kargs.set_tid = set_tid;

	err = copy_clone_args_from_user(&kargs, uargs, size);
	if (err)
		return err;

	if (!clone3_args_valid(&kargs))
		return -EINVAL;

	return kernel_clone(&kargs);
}


static void check_mm(struct mm_struct *mm)
{
	int i;

	BUILD_BUG_ON_MSG(ARRAY_SIZE(resident_page_types) != NR_MM_COUNTERS,
			 "Please make sure 'struct resident_page_types[]' is updated as well");

	for (i = 0; i < NR_MM_COUNTERS; i++) {
		long x = atomic_long_read(&mm->rss_stat.count[i]);

		if (unlikely(x))
			pr_alert("BUG: Bad rss-counter state mm:%p type:%s val:%ld\n",
				 mm, resident_page_types[i], x);
	}

	if (mm_pgtables_bytes(mm))
		pr_alert("BUG: non-zero pgtables_bytes on freeing mm: %ld\n",
				mm_pgtables_bytes(mm));

#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
	VM_BUG_ON_MM(mm->pmd_huge_pte, mm);
#endif
}


static int __init coredump_filter_setup(char *s)
{
	default_dump_filter =
		(simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) &
		MMF_DUMP_FILTER_MASK;
	return 1;
}


SYSCALL_DEFINE0(fork)
{
#ifdef CONFIG_MMU
	struct kernel_clone_args args = {
		.exit_signal = SIGCHLD,
	};

	return kernel_clone(&args);
#else
	/* can not support in nommu mode */
	return -EINVAL;
#endif
}


static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
{
	struct task_struct *tsk;
	unsigned long *stack;
	struct vm_struct *stack_vm_area __maybe_unused;
	int err;

	if (node == NUMA_NO_NODE)
		node = tsk_fork_get_node(orig);
	tsk = alloc_task_struct_node(node);
	if (!tsk)
		return NULL;

	stack = alloc_thread_stack_node(tsk, node);
	if (!stack)
		goto free_tsk;

	if (memcg_charge_kernel_stack(tsk))
		goto free_stack;

	stack_vm_area = task_stack_vm_area(tsk);

	err = arch_dup_task_struct(tsk, orig);

	/*
	 * arch_dup_task_struct() clobbers the stack-related fields.  Make
	 * sure they're properly initialized before using any stack-related
	 * functions again.
	 */
	tsk->stack = stack;
#ifdef CONFIG_VMAP_STACK
	tsk->stack_vm_area = stack_vm_area;
#endif
#ifdef CONFIG_THREAD_INFO_IN_TASK
	refcount_set(&tsk->stack_refcount, 1);
#endif

	if (err)
		goto free_stack;

	err = scs_prepare(tsk, node);
	if (err)
		goto free_stack;

#ifdef CONFIG_SECCOMP
	/*
	 * We must handle setting up seccomp filters once we're under
	 * the sighand lock in case orig has changed between now and
	 * then. Until then, filter must be NULL to avoid messing up
	 * the usage counts on the error path calling free_task.
	 */
	tsk->seccomp.filter = NULL;
#endif

	setup_thread_stack(tsk, orig);
	clear_user_return_notifier(tsk);
	clear_tsk_need_resched(tsk);
	set_task_stack_end_magic(tsk);

#ifdef CONFIG_STACKPROTECTOR
	tsk->stack_canary = get_random_canary();
#endif
	if (orig->cpus_ptr == &orig->cpus_mask)
		tsk->cpus_ptr = &tsk->cpus_mask;

	/*
	 * One for the user space visible state that goes away when reaped.
	 * One for the scheduler.
	 */
	refcount_set(&tsk->rcu_users, 2);
	/* One for the rcu users */
	refcount_set(&tsk->usage, 1);
#ifdef CONFIG_BLK_DEV_IO_TRACE
	tsk->btrace_seq = 0;
#endif
	tsk->splice_pipe = NULL;
	tsk->task_frag.page = NULL;
	tsk->wake_q.next = NULL;

	account_kernel_stack(tsk, 1);

	kcov_task_init(tsk);

#ifdef CONFIG_FAULT_INJECTION
	tsk->fail_nth = 0;
#endif

#ifdef CONFIG_BLK_CGROUP
	tsk->throttle_queue = NULL;
	tsk->use_memdelay = 0;
#endif

#ifdef CONFIG_MEMCG
	tsk->active_memcg = NULL;
#endif
	return tsk;

free_stack:
	free_thread_stack(tsk);
free_tsk:
	free_task_struct(tsk);
	return NULL;
}


static void __delayed_free_task(struct rcu_head *rhp)
{
	struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);

	free_task(tsk);
}


void __mmdrop(struct mm_struct *mm)
{
	BUG_ON(mm == &init_mm);
	WARN_ON_ONCE(mm == current->mm);
	WARN_ON_ONCE(mm == current->active_mm);
	mm_free_pgd(mm);
	destroy_context(mm);
	mmu_notifier_subscriptions_destroy(mm);
	check_mm(mm);
	put_user_ns(mm->user_ns);
	free_mm(mm);
}


static bool clone3_args_valid(struct kernel_clone_args *kargs)
{
	/* Verify that no unknown flags are passed along. */
	if (kargs->flags &
	    ~(CLONE_LEGACY_FLAGS | CLONE_CLEAR_SIGHAND | CLONE_INTO_CGROUP))
		return false;

	/*
	 * - make the CLONE_DETACHED bit reuseable for clone3
	 * - make the CSIGNAL bits reuseable for clone3
	 */
	if (kargs->flags & (CLONE_DETACHED | CSIGNAL))
		return false;

	if ((kargs->flags & (CLONE_SIGHAND | CLONE_CLEAR_SIGHAND)) ==
	    (CLONE_SIGHAND | CLONE_CLEAR_SIGHAND))
		return false;

	if ((kargs->flags & (CLONE_THREAD | CLONE_PARENT)) &&
	    kargs->exit_signal)
		return false;

	if (!clone3_stack_valid(kargs))
		return false;

	return true;
}


static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
{
	struct sighand_struct *sig;

	if (clone_flags & CLONE_SIGHAND) {
		refcount_inc(&current->sighand->count);
		return 0;
	}
	sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
	RCU_INIT_POINTER(tsk->sighand, sig);
	if (!sig)
		return -ENOMEM;

	refcount_set(&sig->count, 1);
	spin_lock_irq(&current->sighand->siglock);
	memcpy(sig->action, current->sighand->action, sizeof(sig->action));
	spin_unlock_irq(&current->sighand->siglock);

	/* Reset all signal handler not set to SIG_IGN to SIG_DFL. */
	if (clone_flags & CLONE_CLEAR_SIGHAND)
		flush_signal_handlers(tsk, 0);

	return 0;
}


static void copy_oom_score_adj(u64 clone_flags, struct task_struct *tsk)
{
	/* Skip if kernel thread */
	if (!tsk->mm)
		return;

	/* Skip if spawning a thread or using vfork */
	if ((clone_flags & (CLONE_VM | CLONE_THREAD | CLONE_VFORK)) != CLONE_VM)
		return;

	/* We need to synchronize with __set_oom_adj */
	mutex_lock(&oom_adj_mutex);
	set_bit(MMF_MULTIPROCESS, &tsk->mm->flags);
	/* Update the values in case they were changed after copy_signal */
	tsk->signal->oom_score_adj = current->signal->oom_score_adj;
	tsk->signal->oom_score_adj_min = current->signal->oom_score_adj_min;
	mutex_unlock(&oom_adj_mutex);
}


static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
{
	mmap_write_lock(oldmm);
	RCU_INIT_POINTER(mm->exe_file, get_mm_exe_file(oldmm));
	mmap_write_unlock(oldmm);
	return 0;
}


static void rt_mutex_init_task(struct task_struct *p)
{
	raw_spin_lock_init(&p->pi_lock);
#ifdef CONFIG_RT_MUTEXES
	p->pi_waiters = RB_ROOT_CACHED;
	p->pi_top_task = NULL;
	p->pi_blocked_on = NULL;
#endif
}


static void task_struct_whitelist(unsigned long *offset, unsigned long *size)
{
	/* Fetch thread_struct whitelist for the architecture. */
	arch_thread_struct_whitelist(offset, size);

	/*
	 * Handle zero-sized whitelist or empty thread_struct, otherwise
	 * adjust offset to position of thread_struct in task_struct.
	 */
	if (unlikely(*size == 0))
		*offset = 0;
	else
		*offset += offsetof(struct task_struct, thread);
}


static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp)
{
	struct fs_struct *fs = current->fs;

	if (!(unshare_flags & CLONE_FS) || !fs)
		return 0;

	/* don't need lock here; in the worst case we'll do useless copy */
	if (fs->users == 1)
		return 0;

	*new_fsp = copy_fs_struct(fs);
	if (!*new_fsp)
		return -ENOMEM;

	return 0;
}


static int free_vm_stack_cache(unsigned int cpu)
{
	struct vm_struct **cached_vm_stacks = per_cpu_ptr(cached_stacks, cpu);
	int i;

	for (i = 0; i < NR_CACHED_STACKS; i++) {
		struct vm_struct *vm_stack = cached_vm_stacks[i];

		if (!vm_stack)
			continue;

		vfree(vm_stack->addr);
		cached_vm_stacks[i] = NULL;
	}

	return 0;
}


SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr)
{
	current->clear_child_tid = tidptr;

	return task_pid_vnr(current);
}


int unshare_files(struct files_struct **displaced)
{
	struct task_struct *task = current;
	struct files_struct *copy = NULL;
	int error;

	error = unshare_fd(CLONE_FILES, NR_OPEN_MAX, &copy);
	if (error || !copy) {
		*displaced = NULL;
		return error;
	}
	*displaced = task->files;
	task_lock(task);
	task->files = copy;
	task_unlock(task);
	return 0;
}


void vm_area_free(struct vm_area_struct *vma)
{
	kmem_cache_free(vm_area_cachep, vma);
}


static unsigned long *alloc_thread_stack_node(struct task_struct *tsk,
						  int node)
{
	unsigned long *stack;
	stack = kmem_cache_alloc_node(thread_stack_cache, THREADINFO_GFP, node);
	stack = kasan_reset_tag(stack);
	tsk->stack = stack;
	return stack;
}


struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig)
{
	struct vm_area_struct *new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);

	if (new) {
		ASSERT_EXCLUSIVE_WRITER(orig->vm_flags);
		ASSERT_EXCLUSIVE_WRITER(orig->vm_file);
		/*
		 * orig->shared.rb may be modified concurrently, but the clone
		 * will be reinitialized.
		 */
		*new = data_race(*orig);
		INIT_LIST_HEAD(&new->anon_vma_chain);
		new->vm_next = new->vm_prev = NULL;
	}
	return new;
}


static void mm_init_uprobes_state(struct mm_struct *mm)
{
#ifdef CONFIG_UPROBES
	mm->uprobes_state.xol_area = NULL;
#endif
}


SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
		 int __user *, parent_tidptr,
		 int __user *, child_tidptr,
		 unsigned long, tls)
#endif
{
	struct kernel_clone_args args = {
		.flags		= (lower_32_bits(clone_flags) & ~CSIGNAL),
		.pidfd		= parent_tidptr,
		.child_tid	= child_tidptr,
		.parent_tid	= parent_tidptr,
		.exit_signal	= (lower_32_bits(clone_flags) & CSIGNAL),
		.stack		= newsp,
		.tls		= tls,
	};

	return kernel_clone(&args);
}


void exec_mm_release(struct task_struct *tsk, struct mm_struct *mm)
{
	futex_exec_release(tsk);
	mm_release(tsk, mm);
}


static int check_unshare_flags(unsigned long unshare_flags)
{
	if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
				CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
				CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET|
				CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP|
				CLONE_NEWTIME))
		return -EINVAL;
	/*
	 * Not implemented, but pretend it works if there is nothing
	 * to unshare.  Note that unsharing the address space or the
	 * signal handlers also need to unshare the signal queues (aka
	 * CLONE_THREAD).
	 */
	if (unshare_flags & (CLONE_THREAD | CLONE_SIGHAND | CLONE_VM)) {
		if (!thread_group_empty(current))
			return -EINVAL;
	}
	if (unshare_flags & (CLONE_SIGHAND | CLONE_VM)) {
		if (refcount_read(&current->sighand->count) > 1)
			return -EINVAL;
	}
	if (unshare_flags & CLONE_VM) {
		if (!current_is_single_threaded())
			return -EINVAL;
	}

	return 0;
}


struct task_struct *fork_idle(int cpu)
{
	struct task_struct *task;
	struct kernel_clone_args args = {
		.flags = CLONE_VM,
	};

	task = copy_process(&init_struct_pid, 0, cpu_to_node(cpu), &args);
	if (!IS_ERR(task)) {
		init_idle_pids(task);
		init_idle(task, cpu);
	}

	return task;
}


static inline void free_signal_struct(struct signal_struct *sig)
{
	taskstats_tgid_free(sig);
	sched_autogroup_exit(sig);
	/*
	 * __mmdrop is not safe to call from softirq context on x86 due to
	 * pgd_dtor so postpone it to the async context
	 */
	if (sig->oom_mm)
		mmdrop_async(sig->oom_mm);
	kmem_cache_free(signal_cachep, sig);
}


static void free_thread_stack(struct task_struct *tsk)
{
	kmem_cache_free(thread_stack_cache, tsk->stack);
}


void mmput(struct mm_struct *mm)
{
	might_sleep();

	if (atomic_dec_and_test(&mm->mm_users))
		__mmput(mm);
}


void __init fork_init(void)
{
	int i;
#ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
#ifndef ARCH_MIN_TASKALIGN
#define ARCH_MIN_TASKALIGN	0
#endif
	int align = max_t(int, L1_CACHE_BYTES, ARCH_MIN_TASKALIGN);
	unsigned long useroffset, usersize;

	/* create a slab on which task_structs can be allocated */
	task_struct_whitelist(&useroffset, &usersize);
	task_struct_cachep = kmem_cache_create_usercopy("task_struct",
			arch_task_struct_size, align,
			SLAB_PANIC|SLAB_ACCOUNT,
			useroffset, usersize, NULL);
#endif

	/* do the arch specific task caches init */
	arch_task_cache_init();

	set_max_threads(MAX_THREADS);

	init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2;
	init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2;
	init_task.signal->rlim[RLIMIT_SIGPENDING] =
		init_task.signal->rlim[RLIMIT_NPROC];

	for (i = 0; i < UCOUNT_COUNTS; i++) {
		init_user_ns.ucount_max[i] = max_threads/2;
	}

#ifdef CONFIG_VMAP_STACK
	cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vm_stack_cache",
			  NULL, free_vm_stack_cache);
#endif

	scs_init();

	lockdep_init_task(&init_task);
	uprobes_init();
}


int nr_processes(void)
{
	int cpu;
	int total = 0;

	for_each_possible_cpu(cpu)
		total += per_cpu(process_counts, cpu);

	return total;
}


static inline void put_signal_struct(struct signal_struct *sig)
{
	if (refcount_dec_and_test(&sig->sigcnt))
		free_signal_struct(sig);
}


void __put_task_struct(struct task_struct *tsk)
{
	WARN_ON(!tsk->exit_state);
	WARN_ON(refcount_read(&tsk->usage));
	WARN_ON(tsk == current);

	io_uring_free(tsk);
	cgroup_free(tsk);
	task_numa_free(tsk, true);
	security_task_free(tsk);
	exit_creds(tsk);
	delayacct_tsk_free(tsk);
	put_signal_struct(tsk->signal);

	if (!profile_handoff_task(tsk))
		free_task(tsk);
}


static __poll_t pidfd_poll(struct file *file, struct poll_table_struct *pts)
{
	struct pid *pid = file->private_data;
	__poll_t poll_flags = 0;

	poll_wait(file, &pid->wait_pidfd, pts);

	/*
	 * Inform pollers only when the whole thread group exits.
	 * If the thread group leader exits before all other threads in the
	 * group, then poll(2) should block, similar to the wait(2) family.
	 */
	if (thread_group_exited(pid))
		poll_flags = EPOLLIN | EPOLLRDNORM;

	return poll_flags;
}


static void mm_init_aio(struct mm_struct *mm)
{
#ifdef CONFIG_AIO
	spin_lock_init(&mm->ioctx_lock);
	mm->ioctx_table = NULL;
#endif
}


static inline void init_task_pid_links(struct task_struct *task)
{
	enum pid_type type;

	for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) {
		INIT_HLIST_NODE(&task->pid_links[type]);
	}
}


static void mmdrop_async(struct mm_struct *mm)
{
	if (unlikely(atomic_dec_and_test(&mm->mm_count))) {
		INIT_WORK(&mm->async_put_work, mmdrop_async_fn);
		schedule_work(&mm->async_put_work);
	}
}


void walk_process_tree(struct task_struct *top, proc_visitor visitor, void *data)
{
	struct task_struct *leader, *parent, *child;
	int res;

	read_lock(&tasklist_lock);
	leader = top = top->group_leader;
down:
	for_each_thread(leader, parent) {
		list_for_each_entry(child, &parent->children, sibling) {
			res = visitor(child, data);
			if (res) {
				if (res < 0)
					goto out;
				leader = child;
				goto down;
			}
up:
			;
		}
	}

	if (leader != top) {
		child = leader;
		parent = child->real_parent;
		leader = parent->group_leader;
		goto up;
	}
out:
	read_unlock(&tasklist_lock);
}


struct vm_area_struct *vm_area_alloc(struct mm_struct *mm)
{
	struct vm_area_struct *vma;

	vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
	if (vma)
		vma_init(vma, mm);
	return vma;
}


struct mm_struct *get_task_mm(struct task_struct *task)
{
	struct mm_struct *mm;

	task_lock(task);
	mm = task->mm;
	if (mm) {
		if (task->flags & PF_KTHREAD)
			mm = NULL;
		else
			mmget(mm);
	}
	task_unlock(task);
	return mm;
}


static __always_inline void delayed_free_task(struct task_struct *tsk)
{
	if (IS_ENABLED(CONFIG_MEMCG))
		call_rcu(&tsk->rcu, __delayed_free_task);
	else
		free_task(tsk);
}


static inline void free_task_struct(struct task_struct *tsk)
{
	kmem_cache_free(task_struct_cachep, tsk);
}


SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
{
	return ksys_unshare(unshare_flags);
}


static void mm_release(struct task_struct *tsk, struct mm_struct *mm)
{
	uprobe_free_utask(tsk);

	/* Get rid of any cached register state */
	deactivate_mm(tsk, mm);

	/*
	 * Signal userspace if we're not exiting with a core dump
	 * because we want to leave the value intact for debugging
	 * purposes.
	 */
	if (tsk->clear_child_tid) {
		if (!(tsk->signal->flags & SIGNAL_GROUP_COREDUMP) &&
		    atomic_read(&mm->mm_users) > 1) {
			/*
			 * We don't check the error code - if userspace has
			 * not set up a proper pointer then tough luck.
			 */
			put_user(0, tsk->clear_child_tid);
			do_futex(tsk->clear_child_tid, FUTEX_WAKE,
					1, NULL, NULL, 0, 0);
		}
		tsk->clear_child_tid = NULL;
	}

	/*
	 * All done, finally we can wake up parent and return this mm to him.
	 * Also kthread_stop() uses this completion for synchronization.
	 */
	if (tsk->vfork_done)
		complete_vfork_done(tsk);
}


static int memcg_charge_kernel_stack(struct task_struct *tsk)
{
#ifdef CONFIG_VMAP_STACK
	struct vm_struct *vm = task_stack_vm_area(tsk);
	int ret;

	BUILD_BUG_ON(IS_ENABLED(CONFIG_VMAP_STACK) && PAGE_SIZE % 1024 != 0);

	if (vm) {
		int i;

		BUG_ON(vm->nr_pages != THREAD_SIZE / PAGE_SIZE);

		for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) {
			/*
			 * If memcg_kmem_charge_page() fails, page->mem_cgroup
			 * pointer is NULL, and memcg_kmem_uncharge_page() in
			 * free_thread_stack() will ignore this page.
			 */
			ret = memcg_kmem_charge_page(vm->pages[i], GFP_KERNEL,
						     0);
			if (ret)
				return ret;
		}
	}
#endif
	return 0;
}


int sysctl_max_threads(struct ctl_table *table, int write,
		       void *buffer, size_t *lenp, loff_t *ppos)
{
	struct ctl_table t;
	int ret;
	int threads = max_threads;
	int min = 1;
	int max = MAX_THREADS;

	t = *table;
	t.data = &threads;
	t.extra1 = &min;
	t.extra2 = &max;

	ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
	if (ret || !write)
		return ret;

	max_threads = threads;

	return 0;
}


struct mm_struct *mm_access(struct task_struct *task, unsigned int mode)
{
	struct mm_struct *mm;
	int err;

	err =  mutex_lock_killable(&task->signal->exec_update_mutex);
	if (err)
		return ERR_PTR(err);

	mm = get_task_mm(task);
	if (mm && mm != current->mm &&
			!ptrace_may_access(task, mode)) {
		mmput(mm);
		mm = ERR_PTR(-EACCES);
	}
	mutex_unlock(&task->signal->exec_update_mutex);

	return mm;
}


static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
	struct user_namespace *user_ns)
{
	mm->mmap = NULL;
	mm->mm_rb = RB_ROOT;
	mm->vmacache_seqnum = 0;
	atomic_set(&mm->mm_users, 1);
	atomic_set(&mm->mm_count, 1);
	mmap_init_lock(mm);
	INIT_LIST_HEAD(&mm->mmlist);
	mm->core_state = NULL;
	mm_pgtables_bytes_init(mm);
	mm->map_count = 0;
	mm->locked_vm = 0;
	atomic_set(&mm->has_pinned, 0);
	atomic64_set(&mm->pinned_vm, 0);
	memset(&mm->rss_stat, 0, sizeof(mm->rss_stat));
	spin_lock_init(&mm->page_table_lock);
	spin_lock_init(&mm->arg_lock);
	mm_init_cpumask(mm);
	mm_init_aio(mm);
	mm_init_owner(mm, p);
	RCU_INIT_POINTER(mm->exe_file, NULL);
	mmu_notifier_subscriptions_init(mm);
	init_tlb_flush_pending(mm);
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
	mm->pmd_huge_pte = NULL;
#endif
	mm_init_uprobes_state(mm);

	if (current->mm) {
		mm->flags = current->mm->flags & MMF_INIT_MASK;
		mm->def_flags = current->mm->def_flags & VM_INIT_DEF_MASK;
	} else {
		mm->flags = default_dump_filter;
		mm->def_flags = 0;
	}

	if (mm_alloc_pgd(mm))
		goto fail_nopgd;

	if (init_new_context(p, mm))
		goto fail_nocontext;

	mm->user_ns = get_user_ns(user_ns);
	return mm;

fail_nocontext:
	mm_free_pgd(mm);
fail_nopgd:
	free_mm(mm);
	return NULL;
}


struct pid *pidfd_pid(const struct file *file)
{
	if (file->f_op == &pidfd_fops)
		return file->private_data;

	return ERR_PTR(-EBADF);
}


static int copy_files(unsigned long clone_flags, struct task_struct *tsk)
{
	struct files_struct *oldf, *newf;
	int error = 0;

	/*
	 * A background process may not have any files ...
	 */
	oldf = current->files;
	if (!oldf)
		goto out;

	if (clone_flags & CLONE_FILES) {
		atomic_inc(&oldf->count);
		goto out;
	}

	newf = dup_fd(oldf, NR_OPEN_MAX, &error);
	if (!newf)
		goto out;

	tsk->files = newf;
	error = 0;
out:
	return error;
}


SYSCALL_DEFINE0(vfork)
{
	struct kernel_clone_args args = {
		.flags		= CLONE_VFORK | CLONE_VM,
		.exit_signal	= SIGCHLD,
	};

	return kernel_clone(&args);
}


static inline void __mmput(struct mm_struct *mm)
{
	VM_BUG_ON(atomic_read(&mm->mm_users));

	uprobe_clear_state(mm);
	exit_aio(mm);
	ksm_exit(mm);
	khugepaged_exit(mm); /* must run before exit_mmap */
	exit_mmap(mm);
	mm_put_huge_zero_page(mm);
	set_mm_exe_file(mm, NULL);
	if (!list_empty(&mm->mmlist)) {
		spin_lock(&mmlist_lock);
		list_del(&mm->mmlist);
		spin_unlock(&mmlist_lock);
	}
	if (mm->binfmt)
		module_put(mm->binfmt->module);
	mmdrop(mm);
}


static int pidfd_release(struct inode *inode, struct file *file)
{
	struct pid *pid = file->private_data;

	file->private_data = NULL;
	put_pid(pid);
	return 0;
}


static inline void mm_free_pgd(struct mm_struct *mm)
{
	pgd_free(mm, mm->pgd);
}


static void account_kernel_stack(struct task_struct *tsk, int account)
{
	void *stack = task_stack_page(tsk);
	struct vm_struct *vm = task_stack_vm_area(tsk);

	/* All stack pages are in the same node. */
	if (vm)
		mod_lruvec_page_state(vm->pages[0], NR_KERNEL_STACK_KB,
				      account * (THREAD_SIZE / 1024));
	else
		mod_lruvec_slab_state(stack, NR_KERNEL_STACK_KB,
				      account * (THREAD_SIZE / 1024));
}


static void sighand_ctor(void *data)
{
	struct sighand_struct *sighand = data;

	spin_lock_init(&sighand->siglock);
	init_waitqueue_head(&sighand->signalfd_wqh);
}


static inline int mm_alloc_pgd(struct mm_struct *mm)
{
	mm->pgd = pgd_alloc(mm);
	if (unlikely(!mm->pgd))
		return -ENOMEM;
	return 0;
}


static int copy_fs(unsigned long clone_flags, struct task_struct *tsk)
{
	struct fs_struct *fs = current->fs;
	if (clone_flags & CLONE_FS) {
		/* tsk->fs is already what we want */
		spin_lock(&fs->lock);
		if (fs->in_exec) {
			spin_unlock(&fs->lock);
			return -EAGAIN;
		}
		fs->users++;
		spin_unlock(&fs->lock);
		return 0;
	}
	tsk->fs = copy_fs_struct(fs);
	if (!tsk->fs)
		return -ENOMEM;
	return 0;
}


static int copy_io(unsigned long clone_flags, struct task_struct *tsk)
{
#ifdef CONFIG_BLOCK
	struct io_context *ioc = current->io_context;
	struct io_context *new_ioc;

	if (!ioc)
		return 0;
	/*
	 * Share io context with parent, if CLONE_IO is set
	 */
	if (clone_flags & CLONE_IO) {
		ioc_task_link(ioc);
		tsk->io_context = ioc;
	} else if (ioprio_valid(ioc->ioprio)) {
		new_ioc = get_task_io_context(tsk, GFP_KERNEL, NUMA_NO_NODE);
		if (unlikely(!new_ioc))
			return -ENOMEM;

		new_ioc->ioprio = ioc->ioprio;
		put_io_context(new_ioc);
	}
#endif
	return 0;
}


pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
{
	struct kernel_clone_args args = {
		.flags		= ((lower_32_bits(flags) | CLONE_VM |
				    CLONE_UNTRACED) & ~CSIGNAL),
		.exit_signal	= (lower_32_bits(flags) & CSIGNAL),
		.stack		= (unsigned long)fn,
		.stack_size	= (unsigned long)arg,
	};

	return kernel_clone(&args);
}


int __weak arch_dup_task_struct(struct task_struct *dst,
					       struct task_struct *src)
{
	*dst = *src;
	return 0;
}


static void complete_vfork_done(struct task_struct *tsk)
{
	struct completion *vfork;

	task_lock(tsk);
	vfork = tsk->vfork_done;
	if (likely(vfork)) {
		tsk->vfork_done = NULL;
		complete(vfork);
	}
	task_unlock(tsk);
}


static inline void free_thread_stack(struct task_struct *tsk)
{
#ifdef CONFIG_VMAP_STACK
	struct vm_struct *vm = task_stack_vm_area(tsk);

	if (vm) {
		int i;

		for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++)
			memcg_kmem_uncharge_page(vm->pages[i], 0);

		for (i = 0; i < NR_CACHED_STACKS; i++) {
			if (this_cpu_cmpxchg(cached_stacks[i],
					NULL, tsk->stack_vm_area) != NULL)
				continue;

			return;
		}

		vfree_atomic(tsk->stack);
		return;
	}
#endif

	__free_pages(virt_to_page(tsk->stack), THREAD_SIZE_ORDER);
}


static __latent_entropy struct task_struct *copy_process(
					struct pid *pid,
					int trace,
					int node,
					struct kernel_clone_args *args)
{
	int pidfd = -1, retval;
	struct task_struct *p;
	struct multiprocess_signals delayed;
	struct file *pidfile = NULL;
	u64 clone_flags = args->flags;
	struct nsproxy *nsp = current->nsproxy;

	/*
	 * Don't allow sharing the root directory with processes in a different
	 * namespace
	 */
	if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
		return ERR_PTR(-EINVAL);

	if ((clone_flags & (CLONE_NEWUSER|CLONE_FS)) == (CLONE_NEWUSER|CLONE_FS))
		return ERR_PTR(-EINVAL);

	/*
	 * Thread groups must share signals as well, and detached threads
	 * can only be started up within the thread group.
	 */
	if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND))
		return ERR_PTR(-EINVAL);

	/*
	 * Shared signal handlers imply shared VM. By way of the above,
	 * thread groups also imply shared VM. Blocking this case allows
	 * for various simplifications in other code.
	 */
	if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM))
		return ERR_PTR(-EINVAL);

	/*
	 * Siblings of global init remain as zombies on exit since they are
	 * not reaped by their parent (swapper). To solve this and to avoid
	 * multi-rooted process trees, prevent global and container-inits
	 * from creating siblings.
	 */
	if ((clone_flags & CLONE_PARENT) &&
				current->signal->flags & SIGNAL_UNKILLABLE)
		return ERR_PTR(-EINVAL);

	/*
	 * If the new process will be in a different pid or user namespace
	 * do not allow it to share a thread group with the forking task.
	 */
	if (clone_flags & CLONE_THREAD) {
		if ((clone_flags & (CLONE_NEWUSER | CLONE_NEWPID)) ||
		    (task_active_pid_ns(current) != nsp->pid_ns_for_children))
			return ERR_PTR(-EINVAL);
	}

	/*
	 * If the new process will be in a different time namespace
	 * do not allow it to share VM or a thread group with the forking task.
	 */
	if (clone_flags & (CLONE_THREAD | CLONE_VM)) {
		if (nsp->time_ns != nsp->time_ns_for_children)
			return ERR_PTR(-EINVAL);
	}

	if (clone_flags & CLONE_PIDFD) {
		/*
		 * - CLONE_DETACHED is blocked so that we can potentially
		 *   reuse it later for CLONE_PIDFD.
		 * - CLONE_THREAD is blocked until someone really needs it.
		 */
		if (clone_flags & (CLONE_DETACHED | CLONE_THREAD))
			return ERR_PTR(-EINVAL);
	}

	/*
	 * Force any signals received before this point to be delivered
	 * before the fork happens.  Collect up signals sent to multiple
	 * processes that happen during the fork and delay them so that
	 * they appear to happen after the fork.
	 */
	sigemptyset(&delayed.signal);
	INIT_HLIST_NODE(&delayed.node);

	spin_lock_irq(&current->sighand->siglock);
	if (!(clone_flags & CLONE_THREAD))
		hlist_add_head(&delayed.node, &current->signal->multiprocess);
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);
	retval = -ERESTARTNOINTR;
	if (signal_pending(current))
		goto fork_out;

	retval = -ENOMEM;
	p = dup_task_struct(current, node);
	if (!p)
		goto fork_out;

	/*
	 * This _must_ happen before we call free_task(), i.e. before we jump
	 * to any of the bad_fork_* labels. This is to avoid freeing
	 * p->set_child_tid which is (ab)used as a kthread's data pointer for
	 * kernel threads (PF_KTHREAD).
	 */
	p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? args->child_tid : NULL;
	/*
	 * Clear TID on mm_release()?
	 */
	p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? args->child_tid : NULL;

	ftrace_graph_init_task(p);

	rt_mutex_init_task(p);

	lockdep_assert_irqs_enabled();
#ifdef CONFIG_PROVE_LOCKING
	DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled);
#endif
	retval = -EAGAIN;
	if (atomic_read(&p->real_cred->user->processes) >=
			task_rlimit(p, RLIMIT_NPROC)) {
		if (p->real_cred->user != INIT_USER &&
		    !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN))
			goto bad_fork_free;
	}
	current->flags &= ~PF_NPROC_EXCEEDED;

	retval = copy_creds(p, clone_flags);
	if (retval < 0)
		goto bad_fork_free;

	/*
	 * If multiple threads are within copy_process(), then this check
	 * triggers too late. This doesn't hurt, the check is only there
	 * to stop root fork bombs.
	 */
	retval = -EAGAIN;
	if (data_race(nr_threads >= max_threads))
		goto bad_fork_cleanup_count;

	delayacct_tsk_init(p);	/* Must remain after dup_task_struct() */
	p->flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER | PF_IDLE);
	p->flags |= PF_FORKNOEXEC;
	INIT_LIST_HEAD(&p->children);
	INIT_LIST_HEAD(&p->sibling);
	rcu_copy_process(p);
	p->vfork_done = NULL;
	spin_lock_init(&p->alloc_lock);

	init_sigpending(&p->pending);

	p->utime = p->stime = p->gtime = 0;
#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
	p->utimescaled = p->stimescaled = 0;
#endif
	prev_cputime_init(&p->prev_cputime);

#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
	seqcount_init(&p->vtime.seqcount);
	p->vtime.starttime = 0;
	p->vtime.state = VTIME_INACTIVE;
#endif

#ifdef CONFIG_IO_URING
	p->io_uring = NULL;
#endif

#if defined(SPLIT_RSS_COUNTING)
	memset(&p->rss_stat, 0, sizeof(p->rss_stat));
#endif

	p->default_timer_slack_ns = current->timer_slack_ns;

#ifdef CONFIG_PSI
	p->psi_flags = 0;
#endif

	task_io_accounting_init(&p->ioac);
	acct_clear_integrals(p);

	posix_cputimers_init(&p->posix_cputimers);

	p->io_context = NULL;
	audit_set_context(p, NULL);
	cgroup_fork(p);
#ifdef CONFIG_NUMA
	p->mempolicy = mpol_dup(p->mempolicy);
	if (IS_ERR(p->mempolicy)) {
		retval = PTR_ERR(p->mempolicy);
		p->mempolicy = NULL;
		goto bad_fork_cleanup_threadgroup_lock;
	}
#endif
#ifdef CONFIG_CPUSETS
	p->cpuset_mem_spread_rotor = NUMA_NO_NODE;
	p->cpuset_slab_spread_rotor = NUMA_NO_NODE;
	seqcount_spinlock_init(&p->mems_allowed_seq, &p->alloc_lock);
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
	memset(&p->irqtrace, 0, sizeof(p->irqtrace));
	p->irqtrace.hardirq_disable_ip	= _THIS_IP_;
	p->irqtrace.softirq_enable_ip	= _THIS_IP_;
	p->softirqs_enabled		= 1;
	p->softirq_context		= 0;
#endif

	p->pagefault_disabled = 0;

#ifdef CONFIG_LOCKDEP
	lockdep_init_task(p);
#endif

#ifdef CONFIG_DEBUG_MUTEXES
	p->blocked_on = NULL; /* not blocked yet */
#endif
#ifdef CONFIG_BCACHE
	p->sequential_io	= 0;
	p->sequential_io_avg	= 0;
#endif

	/* Perform scheduler related setup. Assign this task to a CPU. */
	retval = sched_fork(clone_flags, p);
	if (retval)
		goto bad_fork_cleanup_policy;

	retval = perf_event_init_task(p);
	if (retval)
		goto bad_fork_cleanup_policy;
	retval = audit_alloc(p);
	if (retval)
		goto bad_fork_cleanup_perf;
	/* copy all the process information */
	shm_init_task(p);
	retval = security_task_alloc(p, clone_flags);
	if (retval)
		goto bad_fork_cleanup_audit;
	retval = copy_semundo(clone_flags, p);
	if (retval)
		goto bad_fork_cleanup_security;
	retval = copy_files(clone_flags, p);
	if (retval)
		goto bad_fork_cleanup_semundo;
	retval = copy_fs(clone_flags, p);
	if (retval)
		goto bad_fork_cleanup_files;
	retval = copy_sighand(clone_flags, p);
	if (retval)
		goto bad_fork_cleanup_fs;
	retval = copy_signal(clone_flags, p);
	if (retval)
		goto bad_fork_cleanup_sighand;
	retval = copy_mm(clone_flags, p);
	if (retval)
		goto bad_fork_cleanup_signal;
	retval = copy_namespaces(clone_flags, p);
	if (retval)
		goto bad_fork_cleanup_mm;
	retval = copy_io(clone_flags, p);
	if (retval)
		goto bad_fork_cleanup_namespaces;
	retval = copy_thread(clone_flags, args->stack, args->stack_size, p, args->tls);
	if (retval)
		goto bad_fork_cleanup_io;

	stackleak_task_init(p);

	if (pid != &init_struct_pid) {
		pid = alloc_pid(p->nsproxy->pid_ns_for_children, args->set_tid,
				args->set_tid_size);
		if (IS_ERR(pid)) {
			retval = PTR_ERR(pid);
			goto bad_fork_cleanup_thread;
		}
	}

	/*
	 * This has to happen after we've potentially unshared the file
	 * descriptor table (so that the pidfd doesn't leak into the child
	 * if the fd table isn't shared).
	 */
	if (clone_flags & CLONE_PIDFD) {
		retval = get_unused_fd_flags(O_RDWR | O_CLOEXEC);
		if (retval < 0)
			goto bad_fork_free_pid;

		pidfd = retval;

		pidfile = anon_inode_getfile("[pidfd]", &pidfd_fops, pid,
					      O_RDWR | O_CLOEXEC);
		if (IS_ERR(pidfile)) {
			put_unused_fd(pidfd);
			retval = PTR_ERR(pidfile);
			goto bad_fork_free_pid;
		}
		get_pid(pid);	/* held by pidfile now */

		retval = put_user(pidfd, args->pidfd);
		if (retval)
			goto bad_fork_put_pidfd;
	}

#ifdef CONFIG_BLOCK
	p->plug = NULL;
#endif
	futex_init_task(p);

	/*
	 * sigaltstack should be cleared when sharing the same VM
	 */
	if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM)
		sas_ss_reset(p);

	/*
	 * Syscall tracing and stepping should be turned off in the
	 * child regardless of CLONE_PTRACE.
	 */
	user_disable_single_step(p);
	clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE);
#ifdef TIF_SYSCALL_EMU
	clear_tsk_thread_flag(p, TIF_SYSCALL_EMU);
#endif
	clear_tsk_latency_tracing(p);

	/* ok, now we should be set up.. */
	p->pid = pid_nr(pid);
	if (clone_flags & CLONE_THREAD) {
		p->group_leader = current->group_leader;
		p->tgid = current->tgid;
	} else {
		p->group_leader = p;
		p->tgid = p->pid;
	}

	p->nr_dirtied = 0;
	p->nr_dirtied_pause = 128 >> (PAGE_SHIFT - 10);
	p->dirty_paused_when = 0;

	p->pdeath_signal = 0;
	INIT_LIST_HEAD(&p->thread_group);
	p->task_works = NULL;

	/*
	 * Ensure that the cgroup subsystem policies allow the new process to be
	 * forked. It should be noted that the new process's css_set can be changed
	 * between here and cgroup_post_fork() if an organisation operation is in
	 * progress.
	 */
	retval = cgroup_can_fork(p, args);
	if (retval)
		goto bad_fork_put_pidfd;

	/*
	 * From this point on we must avoid any synchronous user-space
	 * communication until we take the tasklist-lock. In particular, we do
	 * not want user-space to be able to predict the process start-time by
	 * stalling fork(2) after we recorded the start_time but before it is
	 * visible to the system.
	 */

	p->start_time = ktime_get_ns();
	p->start_boottime = ktime_get_boottime_ns();

	/*
	 * Make it visible to the rest of the system, but dont wake it up yet.
	 * Need tasklist lock for parent etc handling!
	 */
	write_lock_irq(&tasklist_lock);

	/* CLONE_PARENT re-uses the old parent */
	if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) {
		p->real_parent = current->real_parent;
		p->parent_exec_id = current->parent_exec_id;
		if (clone_flags & CLONE_THREAD)
			p->exit_signal = -1;
		else
			p->exit_signal = current->group_leader->exit_signal;
	} else {
		p->real_parent = current;
		p->parent_exec_id = current->self_exec_id;
		p->exit_signal = args->exit_signal;
	}

	klp_copy_process(p);

	spin_lock(&current->sighand->siglock);

	/*
	 * Copy seccomp details explicitly here, in case they were changed
	 * before holding sighand lock.
	 */
	copy_seccomp(p);

	rseq_fork(p, clone_flags);

	/* Don't start children in a dying pid namespace */
	if (unlikely(!(ns_of_pid(pid)->pid_allocated & PIDNS_ADDING))) {
		retval = -ENOMEM;
		goto bad_fork_cancel_cgroup;
	}

	/* Let kill terminate clone/fork in the middle */
	if (fatal_signal_pending(current)) {
		retval = -EINTR;
		goto bad_fork_cancel_cgroup;
	}

	/* past the last point of failure */
	if (pidfile)
		fd_install(pidfd, pidfile);

	init_task_pid_links(p);
	if (likely(p->pid)) {
		ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace);

		init_task_pid(p, PIDTYPE_PID, pid);
		if (thread_group_leader(p)) {
			init_task_pid(p, PIDTYPE_TGID, pid);
			init_task_pid(p, PIDTYPE_PGID, task_pgrp(current));
			init_task_pid(p, PIDTYPE_SID, task_session(current));

			if (is_child_reaper(pid)) {
				ns_of_pid(pid)->child_reaper = p;
				p->signal->flags |= SIGNAL_UNKILLABLE;
			}
			p->signal->shared_pending.signal = delayed.signal;
			p->signal->tty = tty_kref_get(current->signal->tty);
			/*
			 * Inherit has_child_subreaper flag under the same
			 * tasklist_lock with adding child to the process tree
			 * for propagate_has_child_subreaper optimization.
			 */
			p->signal->has_child_subreaper = p->real_parent->signal->has_child_subreaper ||
							 p->real_parent->signal->is_child_subreaper;
			list_add_tail(&p->sibling, &p->real_parent->children);
			list_add_tail_rcu(&p->tasks, &init_task.tasks);
			attach_pid(p, PIDTYPE_TGID);
			attach_pid(p, PIDTYPE_PGID);
			attach_pid(p, PIDTYPE_SID);
			__this_cpu_inc(process_counts);
		} else {
			current->signal->nr_threads++;
			atomic_inc(&current->signal->live);
			refcount_inc(&current->signal->sigcnt);
			task_join_group_stop(p);
			list_add_tail_rcu(&p->thread_group,
					  &p->group_leader->thread_group);
			list_add_tail_rcu(&p->thread_node,
					  &p->signal->thread_head);
		}
		attach_pid(p, PIDTYPE_PID);
		nr_threads++;
	}
	total_forks++;
	hlist_del_init(&delayed.node);
	spin_unlock(&current->sighand->siglock);
	syscall_tracepoint_update(p);
	write_unlock_irq(&tasklist_lock);

	proc_fork_connector(p);
	sched_post_fork(p);
	cgroup_post_fork(p, args);
	perf_event_fork(p);

	trace_task_newtask(p, clone_flags);
	uprobe_copy_process(p, clone_flags);

	copy_oom_score_adj(clone_flags, p);

	return p;

bad_fork_cancel_cgroup:
	spin_unlock(&current->sighand->siglock);
	write_unlock_irq(&tasklist_lock);
	cgroup_cancel_fork(p, args);
bad_fork_put_pidfd:
	if (clone_flags & CLONE_PIDFD) {
		fput(pidfile);
		put_unused_fd(pidfd);
	}
bad_fork_free_pid:
	if (pid != &init_struct_pid)
		free_pid(pid);
bad_fork_cleanup_thread:
	exit_thread(p);
bad_fork_cleanup_io:
	if (p->io_context)
		exit_io_context(p);
bad_fork_cleanup_namespaces:
	exit_task_namespaces(p);
bad_fork_cleanup_mm:
	if (p->mm) {
		mm_clear_owner(p->mm, p);
		mmput(p->mm);
	}
bad_fork_cleanup_signal:
	if (!(clone_flags & CLONE_THREAD))
		free_signal_struct(p->signal);
bad_fork_cleanup_sighand:
	__cleanup_sighand(p->sighand);
bad_fork_cleanup_fs:
	exit_fs(p); /* blocking */
bad_fork_cleanup_files:
	exit_files(p); /* blocking */
bad_fork_cleanup_semundo:
	exit_sem(p);
bad_fork_cleanup_security:
	security_task_free(p);
bad_fork_cleanup_audit:
	audit_free(p);
bad_fork_cleanup_perf:
	perf_event_free_task(p);
bad_fork_cleanup_policy:
	lockdep_free_task(p);
#ifdef CONFIG_NUMA
	mpol_put(p->mempolicy);
bad_fork_cleanup_threadgroup_lock:
#endif
	delayacct_tsk_free(p);
bad_fork_cleanup_count:
	atomic_dec(&p->cred->user->processes);
	exit_creds(p);
bad_fork_free:
	p->state = TASK_DEAD;
	put_task_stack(p);
	delayed_free_task(p);
fork_out:
	spin_lock_irq(&current->sighand->siglock);
	hlist_del_init(&delayed.node);
	spin_unlock_irq(&current->sighand->siglock);
	return ERR_PTR(retval);
}


static void release_task_stack(struct task_struct *tsk)
{
	if (WARN_ON(tsk->state != TASK_DEAD))
		return;  /* Better to leak the stack than to free prematurely */

	account_kernel_stack(tsk, -1);
	free_thread_stack(tsk);
	tsk->stack = NULL;
#ifdef CONFIG_VMAP_STACK
	tsk->stack_vm_area = NULL;
#endif
}


void set_task_stack_end_magic(struct task_struct *tsk)
{
	unsigned long *stackend;

	stackend = end_of_stack(tsk);
	*stackend = STACK_END_MAGIC;	/* for overflow detection */
}


void thread_stack_cache_init(void)
{
	thread_stack_cache = kmem_cache_create_usercopy("thread_stack",
					THREAD_SIZE, THREAD_SIZE, 0, 0,
					THREAD_SIZE, NULL);
	BUG_ON(thread_stack_cache == NULL);
}


static inline void rcu_copy_process(struct task_struct *p)
{
#ifdef CONFIG_PREEMPT_RCU
	p->rcu_read_lock_nesting = 0;
	p->rcu_read_unlock_special.s = 0;
	p->rcu_blocked_node = NULL;
	INIT_LIST_HEAD(&p->rcu_node_entry);
#endif /* #ifdef CONFIG_PREEMPT_RCU */
#ifdef CONFIG_TASKS_RCU
	p->rcu_tasks_holdout = false;
	INIT_LIST_HEAD(&p->rcu_tasks_holdout_list);
	p->rcu_tasks_idle_cpu = -1;
#endif /* #ifdef CONFIG_TASKS_RCU */
#ifdef CONFIG_TASKS_TRACE_RCU
	p->trc_reader_nesting = 0;
	p->trc_reader_special.s = 0;
	INIT_LIST_HEAD(&p->trc_holdout_list);
#endif /* #ifdef CONFIG_TASKS_TRACE_RCU */
}


pid_t kernel_clone(struct kernel_clone_args *args)
{
	u64 clone_flags = args->flags;
	struct completion vfork;
	struct pid *pid;
	struct task_struct *p;
	int trace = 0;
	pid_t nr;

	/*
	 * For legacy clone() calls, CLONE_PIDFD uses the parent_tid argument
	 * to return the pidfd. Hence, CLONE_PIDFD and CLONE_PARENT_SETTID are
	 * mutually exclusive. With clone3() CLONE_PIDFD has grown a separate
	 * field in struct clone_args and it still doesn't make sense to have
	 * them both point at the same memory location. Performing this check
	 * here has the advantage that we don't need to have a separate helper
	 * to check for legacy clone().
	 */
	if ((args->flags & CLONE_PIDFD) &&
	    (args->flags & CLONE_PARENT_SETTID) &&
	    (args->pidfd == args->parent_tid))
		return -EINVAL;

	/*
	 * Determine whether and which event to report to ptracer.  When
	 * called from kernel_thread or CLONE_UNTRACED is explicitly
	 * requested, no event is reported; otherwise, report if the event
	 * for the type of forking is enabled.
	 */
	if (!(clone_flags & CLONE_UNTRACED)) {
		if (clone_flags & CLONE_VFORK)
			trace = PTRACE_EVENT_VFORK;
		else if (args->exit_signal != SIGCHLD)
			trace = PTRACE_EVENT_CLONE;
		else
			trace = PTRACE_EVENT_FORK;

		if (likely(!ptrace_event_enabled(current, trace)))
			trace = 0;
	}

	p = copy_process(NULL, trace, NUMA_NO_NODE, args);
	add_latent_entropy();

	if (IS_ERR(p))
		return PTR_ERR(p);

	/*
	 * Do this prior waking up the new thread - the thread pointer
	 * might get invalid after that point, if the thread exits quickly.
	 */
	trace_sched_process_fork(current, p);

	pid = get_task_pid(p, PIDTYPE_PID);
	nr = pid_vnr(pid);

	if (clone_flags & CLONE_PARENT_SETTID)
		put_user(nr, args->parent_tid);

	if (clone_flags & CLONE_VFORK) {
		p->vfork_done = &vfork;
		init_completion(&vfork);
		get_task_struct(p);
	}

	wake_up_new_task(p);

	/* forking complete and child started to run, tell ptracer */
	if (unlikely(trace))
		ptrace_event_pid(trace, pid);

	if (clone_flags & CLONE_VFORK) {
		if (!wait_for_vfork_done(p, &vfork))
			ptrace_event_pid(PTRACE_EVENT_VFORK_DONE, pid);
	}

	put_pid(pid);
	return nr;
}


int ksys_unshare(unsigned long unshare_flags)
{
	struct fs_struct *fs, *new_fs = NULL;
	struct files_struct *fd, *new_fd = NULL;
	struct cred *new_cred = NULL;
	struct nsproxy *new_nsproxy = NULL;
	int do_sysvsem = 0;
	int err;

	/*
	 * If unsharing a user namespace must also unshare the thread group
	 * and unshare the filesystem root and working directories.
	 */
	if (unshare_flags & CLONE_NEWUSER)
		unshare_flags |= CLONE_THREAD | CLONE_FS;
	/*
	 * If unsharing vm, must also unshare signal handlers.
	 */
	if (unshare_flags & CLONE_VM)
		unshare_flags |= CLONE_SIGHAND;
	/*
	 * If unsharing a signal handlers, must also unshare the signal queues.
	 */
	if (unshare_flags & CLONE_SIGHAND)
		unshare_flags |= CLONE_THREAD;
	/*
	 * If unsharing namespace, must also unshare filesystem information.
	 */
	if (unshare_flags & CLONE_NEWNS)
		unshare_flags |= CLONE_FS;

	err = check_unshare_flags(unshare_flags);
	if (err)
		goto bad_unshare_out;
	/*
	 * CLONE_NEWIPC must also detach from the undolist: after switching
	 * to a new ipc namespace, the semaphore arrays from the old
	 * namespace are unreachable.
	 */
	if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM))
		do_sysvsem = 1;
	err = unshare_fs(unshare_flags, &new_fs);
	if (err)
		goto bad_unshare_out;
	err = unshare_fd(unshare_flags, NR_OPEN_MAX, &new_fd);
	if (err)
		goto bad_unshare_cleanup_fs;
	err = unshare_userns(unshare_flags, &new_cred);
	if (err)
		goto bad_unshare_cleanup_fd;
	err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy,
					 new_cred, new_fs);
	if (err)
		goto bad_unshare_cleanup_cred;

	if (new_fs || new_fd || do_sysvsem || new_cred || new_nsproxy) {
		if (do_sysvsem) {
			/*
			 * CLONE_SYSVSEM is equivalent to sys_exit().
			 */
			exit_sem(current);
		}
		if (unshare_flags & CLONE_NEWIPC) {
			/* Orphan segments in old ns (see sem above). */
			exit_shm(current);
			shm_init_task(current);
		}

		if (new_nsproxy)
			switch_task_namespaces(current, new_nsproxy);

		task_lock(current);

		if (new_fs) {
			fs = current->fs;
			spin_lock(&fs->lock);
			current->fs = new_fs;
			if (--fs->users)
				new_fs = NULL;
			else
				new_fs = fs;
			spin_unlock(&fs->lock);
		}

		if (new_fd) {
			fd = current->files;
			current->files = new_fd;
			new_fd = fd;
		}

		task_unlock(current);

		if (new_cred) {
			/* Install the new user namespace */
			commit_creds(new_cred);
			new_cred = NULL;
		}
	}

	perf_event_namespaces(current);

bad_unshare_cleanup_cred:
	if (new_cred)
		put_cred(new_cred);
bad_unshare_cleanup_fd:
	if (new_fd)
		put_files_struct(new_fd);

bad_unshare_cleanup_fs:
	if (new_fs)
		free_fs_struct(new_fs);

bad_unshare_out:
	return err;
}


static inline void init_idle_pids(struct task_struct *idle)
{
	enum pid_type type;

	for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) {
		INIT_HLIST_NODE(&idle->pid_links[type]); /* not really needed */
		init_task_pid(idle, type, &init_struct_pid);
	}
}


int unshare_fd(unsigned long unshare_flags, unsigned int max_fds,
	       struct files_struct **new_fdp)
{
	struct files_struct *fd = current->files;
	int error = 0;

	if ((unshare_flags & CLONE_FILES) &&
	    (fd && atomic_read(&fd->count) > 1)) {
		*new_fdp = dup_fd(fd, max_fds, &error);
		if (!*new_fdp)
			return error;
	}

	return 0;
}


noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs,
					      struct clone_args __user *uargs,
					      size_t usize)
{
	int err;
	struct clone_args args;
	pid_t *kset_tid = kargs->set_tid;

	BUILD_BUG_ON(offsetofend(struct clone_args, tls) !=
		     CLONE_ARGS_SIZE_VER0);
	BUILD_BUG_ON(offsetofend(struct clone_args, set_tid_size) !=
		     CLONE_ARGS_SIZE_VER1);
	BUILD_BUG_ON(offsetofend(struct clone_args, cgroup) !=
		     CLONE_ARGS_SIZE_VER2);
	BUILD_BUG_ON(sizeof(struct clone_args) != CLONE_ARGS_SIZE_VER2);

	if (unlikely(usize > PAGE_SIZE))
		return -E2BIG;
	if (unlikely(usize < CLONE_ARGS_SIZE_VER0))
		return -EINVAL;

	err = copy_struct_from_user(&args, sizeof(args), uargs, usize);
	if (err)
		return err;

	if (unlikely(args.set_tid_size > MAX_PID_NS_LEVEL))
		return -EINVAL;

	if (unlikely(!args.set_tid && args.set_tid_size > 0))
		return -EINVAL;

	if (unlikely(args.set_tid && args.set_tid_size == 0))
		return -EINVAL;

	/*
	 * Verify that higher 32bits of exit_signal are unset and that
	 * it is a valid signal
	 */
	if (unlikely((args.exit_signal & ~((u64)CSIGNAL)) ||
		     !valid_signal(args.exit_signal)))
		return -EINVAL;

	if ((args.flags & CLONE_INTO_CGROUP) &&
	    (args.cgroup > INT_MAX || usize < CLONE_ARGS_SIZE_VER2))
		return -EINVAL;

	*kargs = (struct kernel_clone_args){
		.flags		= args.flags,
		.pidfd		= u64_to_user_ptr(args.pidfd),
		.child_tid	= u64_to_user_ptr(args.child_tid),
		.parent_tid	= u64_to_user_ptr(args.parent_tid),
		.exit_signal	= args.exit_signal,
		.stack		= args.stack,
		.stack_size	= args.stack_size,
		.tls		= args.tls,
		.set_tid_size	= args.set_tid_size,
		.cgroup		= args.cgroup,
	};

	if (args.set_tid &&
		copy_from_user(kset_tid, u64_to_user_ptr(args.set_tid),
			(kargs->set_tid_size * sizeof(pid_t))))
		return -EFAULT;

	kargs->set_tid = kset_tid;

	return 0;
}


void free_task(struct task_struct *tsk)
{
	scs_release(tsk);

#ifndef CONFIG_THREAD_INFO_IN_TASK
	/*
	 * The task is finally done with both the stack and thread_info,
	 * so free both.
	 */
	release_task_stack(tsk);
#else
	/*
	 * If the task had a separate stack allocation, it should be gone
	 * by now.
	 */
	WARN_ON_ONCE(refcount_read(&tsk->stack_refcount) != 0);
#endif
	rt_mutex_debug_task_free(tsk);
	ftrace_graph_exit_task(tsk);
	arch_release_task_struct(tsk);
	if (tsk->flags & PF_KTHREAD)
		free_kthread_struct(tsk);
	free_task_struct(tsk);
}


init_task_pid(struct task_struct *task, enum pid_type type, struct pid *pid)
{
	if (type == PIDTYPE_PID)
		task->thread_pid = pid;
	else
		task->signal->pids[type] = pid;
}


static inline struct task_struct *alloc_task_struct_node(int node)
{
	return kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node);
}


static void pidfd_show_fdinfo(struct seq_file *m, struct file *f)
{
	struct pid *pid = f->private_data;
	struct pid_namespace *ns;
	pid_t nr = -1;

	if (likely(pid_has_task(pid, PIDTYPE_PID))) {
		ns = proc_pid_ns(file_inode(m->file)->i_sb);
		nr = pid_nr_ns(pid, ns);
	}

	seq_put_decimal_ll(m, "Pid:\t", nr);

#ifdef CONFIG_PID_NS
	seq_put_decimal_ll(m, "\nNSpid:\t", nr);
	if (nr > 0) {
		int i;

		/* If nr is non-zero it means that 'pid' is valid and that
		 * ns, i.e. the pid namespace associated with the procfs
		 * instance, is in the pid namespace hierarchy of pid.
		 * Start at one below the already printed level.
		 */
		for (i = ns->level + 1; i <= pid->level; i++)
			seq_put_decimal_ll(m, "\t", pid->numbers[i].nr);
	}
#endif
	seq_putc(m, '\n');
}


static void posix_cpu_timers_init_group(struct signal_struct *sig)
{
	struct posix_cputimers *pct = &sig->posix_cputimers;
	unsigned long cpu_limit;

	cpu_limit = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
	posix_cputimers_group_init(pct, cpu_limit);
}


static int wait_for_vfork_done(struct task_struct *child,
				struct completion *vfork)
{
	int killed;

	freezer_do_not_count();
	cgroup_enter_frozen();
	killed = wait_for_completion_killable(vfork);
	cgroup_leave_frozen(false);
	freezer_count();

	if (killed) {
		task_lock(child);
		child->vfork_done = NULL;
		task_unlock(child);
	}

	put_task_struct(child);
	return killed;
}


void __init proc_caches_init(void)
{
	unsigned int mm_size;

	sighand_cachep = kmem_cache_create("sighand_cache",
			sizeof(struct sighand_struct), 0,
			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_TYPESAFE_BY_RCU|
			SLAB_ACCOUNT, sighand_ctor);
	signal_cachep = kmem_cache_create("signal_cache",
			sizeof(struct signal_struct), 0,
			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
			NULL);
	files_cachep = kmem_cache_create("files_cache",
			sizeof(struct files_struct), 0,
			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
			NULL);
	fs_cachep = kmem_cache_create("fs_cache",
			sizeof(struct fs_struct), 0,
			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
			NULL);

	/*
	 * The mm_cpumask is located at the end of mm_struct, and is
	 * dynamically sized based on the maximum CPU number this system
	 * can have, taking hotplug into account (nr_cpu_ids).
	 */
	mm_size = sizeof(struct mm_struct) + cpumask_size();

	mm_cachep = kmem_cache_create_usercopy("mm_struct",
			mm_size, ARCH_MIN_MMSTRUCT_ALIGN,
			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
			offsetof(struct mm_struct, saved_auxv),
			sizeof_field(struct mm_struct, saved_auxv),
			NULL);
	vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC|SLAB_ACCOUNT);
	mmap_init();
	nsproxy_cache_init();
}


struct mm_struct *copy_init_mm(void)
{
	return dup_mm(NULL, &init_mm);
}


static void mmdrop_async_fn(struct work_struct *work)
{
	struct mm_struct *mm;

	mm = container_of(work, struct mm_struct, async_put_work);
	__mmdrop(mm);
}


static struct mm_struct *dup_mm(struct task_struct *tsk,
				struct mm_struct *oldmm)
{
	struct mm_struct *mm;
	int err;

	mm = allocate_mm();
	if (!mm)
		goto fail_nomem;

	memcpy(mm, oldmm, sizeof(*mm));

	if (!mm_init(mm, tsk, mm->user_ns))
		goto fail_nomem;

	err = dup_mmap(mm, oldmm);
	if (err)
		goto free_pt;

	mm->hiwater_rss = get_mm_rss(mm);
	mm->hiwater_vm = mm->total_vm;

	if (mm->binfmt && !try_module_get(mm->binfmt->module))
		goto free_pt;

	return mm;

free_pt:
	/* don't put binfmt in mmput, we haven't got module yet */
	mm->binfmt = NULL;
	mm_init_owner(mm, NULL);
	mmput(mm);

fail_nomem:
	return NULL;
}


static __always_inline void mm_clear_owner(struct mm_struct *mm,
					   struct task_struct *p)
{
#ifdef CONFIG_MEMCG
	if (mm->owner == p)
		WRITE_ONCE(mm->owner, NULL);
#endif
}


void put_task_stack(struct task_struct *tsk)
{
	if (refcount_dec_and_test(&tsk->stack_refcount))
		release_task_stack(tsk);
}


void __weak arch_release_task_struct(struct task_struct *tsk)
{
}


static inline bool clone3_stack_valid(struct kernel_clone_args *kargs)
{
	if (kargs->stack == 0) {
		if (kargs->stack_size > 0)
			return false;
	} else {
		if (kargs->stack_size == 0)
			return false;

		if (!access_ok((void __user *)kargs->stack, kargs->stack_size))
			return false;

#if !defined(CONFIG_STACK_GROWSUP) && !defined(CONFIG_IA64)
		kargs->stack += kargs->stack_size;
#endif
	}

	return true;
}


static void copy_seccomp(struct task_struct *p)
{
#ifdef CONFIG_SECCOMP
	/*
	 * Must be called with sighand->lock held, which is common to
	 * all threads in the group. Holding cred_guard_mutex is not
	 * needed because this new task is not yet running and cannot
	 * be racing exec.
	 */
	assert_spin_locked(&current->sighand->siglock);

	/* Ref-count the new filter user, and assign it. */
	get_seccomp_filter(current);
	p->seccomp = current->seccomp;

	/*
	 * Explicitly enable no_new_privs here in case it got set
	 * between the task_struct being duplicated and holding the
	 * sighand lock. The seccomp state and nnp must be in sync.
	 */
	if (task_no_new_privs(current))
		task_set_no_new_privs(p);

	/*
	 * If the parent gained a seccomp mode after copying thread
	 * flags and between before we held the sighand lock, we have
	 * to manually enable the seccomp thread flag here.
	 */
	if (p->seccomp.mode != SECCOMP_MODE_DISABLED)
		set_tsk_thread_flag(p, TIF_SECCOMP);
#endif
}


static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
{
	struct signal_struct *sig;

	if (clone_flags & CLONE_THREAD)
		return 0;

	sig = kmem_cache_zalloc(signal_cachep, GFP_KERNEL);
	tsk->signal = sig;
	if (!sig)
		return -ENOMEM;

	sig->nr_threads = 1;
	atomic_set(&sig->live, 1);
	refcount_set(&sig->sigcnt, 1);

	/* list_add(thread_node, thread_head) without INIT_LIST_HEAD() */
	sig->thread_head = (struct list_head)LIST_HEAD_INIT(tsk->thread_node);
	tsk->thread_node = (struct list_head)LIST_HEAD_INIT(sig->thread_head);

	init_waitqueue_head(&sig->wait_chldexit);
	sig->curr_target = tsk;
	init_sigpending(&sig->shared_pending);
	INIT_HLIST_HEAD(&sig->multiprocess);
	seqlock_init(&sig->stats_lock);
	prev_cputime_init(&sig->prev_cputime);

#ifdef CONFIG_POSIX_TIMERS
	INIT_LIST_HEAD(&sig->posix_timers);
	hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	sig->real_timer.function = it_real_fn;
#endif

	task_lock(current->group_leader);
	memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim);
	task_unlock(current->group_leader);

	posix_cpu_timers_init_group(sig);

	tty_audit_fork(sig);
	sched_autogroup_fork(sig);

	sig->oom_score_adj = current->signal->oom_score_adj;
	sig->oom_score_adj_min = current->signal->oom_score_adj_min;

	mutex_init(&sig->cred_guard_mutex);
	mutex_init(&sig->exec_update_mutex);

	return 0;
}


int lockdep_tasklist_lock_is_held(void)
{
	return lockdep_is_held(&tasklist_lock);
}


static __latent_entropy int dup_mmap(struct mm_struct *mm,
					struct mm_struct *oldmm)
{
	struct vm_area_struct *mpnt, *tmp, *prev, **pprev;
	struct rb_node **rb_link, *rb_parent;
	int retval;
	unsigned long charge;
	LIST_HEAD(uf);

	uprobe_start_dup_mmap();
	if (mmap_write_lock_killable(oldmm)) {
		retval = -EINTR;
		goto fail_uprobe_end;
	}
	flush_cache_dup_mm(oldmm);
	uprobe_dup_mmap(oldmm, mm);
	/*
	 * Not linked in yet - no deadlock potential:
	 */
	mmap_write_lock_nested(mm, SINGLE_DEPTH_NESTING);

	/* No ordering required: file already has been exposed. */
	RCU_INIT_POINTER(mm->exe_file, get_mm_exe_file(oldmm));

	mm->total_vm = oldmm->total_vm;
	mm->data_vm = oldmm->data_vm;
	mm->exec_vm = oldmm->exec_vm;
	mm->stack_vm = oldmm->stack_vm;

	rb_link = &mm->mm_rb.rb_node;
	rb_parent = NULL;
	pprev = &mm->mmap;
	retval = ksm_fork(mm, oldmm);
	if (retval)
		goto out;
	retval = khugepaged_fork(mm, oldmm);
	if (retval)
		goto out;

	prev = NULL;
	for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) {
		struct file *file;

		if (mpnt->vm_flags & VM_DONTCOPY) {
			vm_stat_account(mm, mpnt->vm_flags, -vma_pages(mpnt));
			continue;
		}
		charge = 0;
		/*
		 * Don't duplicate many vmas if we've been oom-killed (for
		 * example)
		 */
		if (fatal_signal_pending(current)) {
			retval = -EINTR;
			goto out;
		}
		if (mpnt->vm_flags & VM_ACCOUNT) {
			unsigned long len = vma_pages(mpnt);

			if (security_vm_enough_memory_mm(oldmm, len)) /* sic */
				goto fail_nomem;
			charge = len;
		}
		tmp = vm_area_dup(mpnt);
		if (!tmp)
			goto fail_nomem;
		retval = vma_dup_policy(mpnt, tmp);
		if (retval)
			goto fail_nomem_policy;
		tmp->vm_mm = mm;
		retval = dup_userfaultfd(tmp, &uf);
		if (retval)
			goto fail_nomem_anon_vma_fork;
		if (tmp->vm_flags & VM_WIPEONFORK) {
			/*
			 * VM_WIPEONFORK gets a clean slate in the child.
			 * Don't prepare anon_vma until fault since we don't
			 * copy page for current vma.
			 */
			tmp->anon_vma = NULL;
		} else if (anon_vma_fork(tmp, mpnt))
			goto fail_nomem_anon_vma_fork;
		tmp->vm_flags &= ~(VM_LOCKED | VM_LOCKONFAULT);
		file = tmp->vm_file;
		if (file) {
			struct inode *inode = file_inode(file);
			struct address_space *mapping = file->f_mapping;

			get_file(file);
			if (tmp->vm_flags & VM_DENYWRITE)
				put_write_access(inode);
			i_mmap_lock_write(mapping);
			if (tmp->vm_flags & VM_SHARED)
				mapping_allow_writable(mapping);
			flush_dcache_mmap_lock(mapping);
			/* insert tmp into the share list, just after mpnt */
			vma_interval_tree_insert_after(tmp, mpnt,
					&mapping->i_mmap);
			flush_dcache_mmap_unlock(mapping);
			i_mmap_unlock_write(mapping);
		}

		/*
		 * Clear hugetlb-related page reserves for children. This only
		 * affects MAP_PRIVATE mappings. Faults generated by the child
		 * are not guaranteed to succeed, even if read-only
		 */
		if (is_vm_hugetlb_page(tmp))
			reset_vma_resv_huge_pages(tmp);

		/*
		 * Link in the new vma and copy the page table entries.
		 */
		*pprev = tmp;
		pprev = &tmp->vm_next;
		tmp->vm_prev = prev;
		prev = tmp;

		__vma_link_rb(mm, tmp, rb_link, rb_parent);
		rb_link = &tmp->vm_rb.rb_right;
		rb_parent = &tmp->vm_rb;

		mm->map_count++;
		if (!(tmp->vm_flags & VM_WIPEONFORK))
			retval = copy_page_range(tmp, mpnt);

		if (tmp->vm_ops && tmp->vm_ops->open)
			tmp->vm_ops->open(tmp);

		if (retval)
			goto out;
	}
	/* a new mm has just been created */
	retval = arch_dup_mmap(oldmm, mm);
out:
	mmap_write_unlock(mm);
	flush_tlb_mm(oldmm);
	mmap_write_unlock(oldmm);
	dup_userfaultfd_complete(&uf);
fail_uprobe_end:
	uprobe_end_dup_mmap();
	return retval;
fail_nomem_anon_vma_fork:
	mpol_put(vma_policy(tmp));
fail_nomem_policy:
	vm_area_free(tmp);
fail_nomem:
	retval = -ENOMEM;
	vm_unacct_memory(charge);
	goto out;
}


struct file *get_task_exe_file(struct task_struct *task)
{
	struct file *exe_file = NULL;
	struct mm_struct *mm;

	task_lock(task);
	mm = task->mm;
	if (mm) {
		if (!(task->flags & PF_KTHREAD))
			exe_file = get_mm_exe_file(mm);
	}
	task_unlock(task);
	return exe_file;
}


static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
{
#ifdef CONFIG_VMAP_STACK
	void *stack;
	int i;

	for (i = 0; i < NR_CACHED_STACKS; i++) {
		struct vm_struct *s;

		s = this_cpu_xchg(cached_stacks[i], NULL);

		if (!s)
			continue;

		/* Clear the KASAN shadow of the stack. */
		kasan_unpoison_shadow(s->addr, THREAD_SIZE);

		/* Clear stale pointers from reused stack. */
		memset(s->addr, 0, THREAD_SIZE);

		tsk->stack_vm_area = s;
		tsk->stack = s->addr;
		return s->addr;
	}

	/*
	 * Allocated stacks are cached and later reused by new threads,
	 * so memcg accounting is performed manually on assigning/releasing
	 * stacks to tasks. Drop __GFP_ACCOUNT.
	 */
	stack = __vmalloc_node_range(THREAD_SIZE, THREAD_ALIGN,
				     VMALLOC_START, VMALLOC_END,
				     THREADINFO_GFP & ~__GFP_ACCOUNT,
				     PAGE_KERNEL,
				     0, node, __builtin_return_address(0));

	/*
	 * We can't call find_vm_area() in interrupt context, and
	 * free_thread_stack() can be called in interrupt context,
	 * so cache the vm_struct.
	 */
	if (stack) {
		tsk->stack_vm_area = find_vm_area(stack);
		tsk->stack = stack;
	}
	return stack;
#else
	struct page *page = alloc_pages_node(node, THREADINFO_GFP,
					     THREAD_SIZE_ORDER);

	if (likely(page)) {
		tsk->stack = kasan_reset_tag(page_address(page));
		return tsk->stack;
	}
	return NULL;
#endif
}


void __init __weak arch_task_cache_init(void) { }


void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
{
	struct file *old_exe_file;

	/*
	 * It is safe to dereference the exe_file without RCU as
	 * this function is only called if nobody else can access
	 * this mm -- see comment above for justification.
	 */
	old_exe_file = rcu_dereference_raw(mm->exe_file);

	if (new_exe_file)
		get_file(new_exe_file);
	rcu_assign_pointer(mm->exe_file, new_exe_file);
	if (old_exe_file)
		fput(old_exe_file);
}


static int copy_mm(unsigned long clone_flags, struct task_struct *tsk)
{
	struct mm_struct *mm, *oldmm;
	int retval;

	tsk->min_flt = tsk->maj_flt = 0;
	tsk->nvcsw = tsk->nivcsw = 0;
#ifdef CONFIG_DETECT_HUNG_TASK
	tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw;
	tsk->last_switch_time = 0;
#endif

	tsk->mm = NULL;
	tsk->active_mm = NULL;

	/*
	 * Are we cloning a kernel thread?
	 *
	 * We need to steal a active VM for that..
	 */
	oldmm = current->mm;
	if (!oldmm)
		return 0;

	/* initialize the new vmacache entries */
	vmacache_flush(tsk);

	if (clone_flags & CLONE_VM) {
		mmget(oldmm);
		mm = oldmm;
		goto good_mm;
	}

	retval = -ENOMEM;
	mm = dup_mm(tsk, current->mm);
	if (!mm)
		goto fail_nomem;

good_mm:
	tsk->mm = mm;
	tsk->active_mm = mm;
	return 0;

fail_nomem:
	return retval;
}


struct mm_struct *mm_alloc(void)
{
	struct mm_struct *mm;

	mm = allocate_mm();
	if (!mm)
		return NULL;

	memset(mm, 0, sizeof(*mm));
	return mm_init(mm, current, current_user_ns());
}


static void mmput_async_fn(struct work_struct *work)
{
	struct mm_struct *mm = container_of(work, struct mm_struct,
					    async_put_work);

	__mmput(mm);
}


struct file *get_mm_exe_file(struct mm_struct *mm)
{
	struct file *exe_file;

	rcu_read_lock();
	exe_file = rcu_dereference(mm->exe_file);
	if (exe_file && !get_file_rcu(exe_file))
		exe_file = NULL;
	rcu_read_unlock();
	return exe_file;
}


static void mm_init_owner(struct mm_struct *mm, struct task_struct *p)
{
#ifdef CONFIG_MEMCG
	mm->owner = p;
#endif
}


void exit_mm_release(struct task_struct *tsk, struct mm_struct *mm)
{
	futex_exit_release(tsk);
	mm_release(tsk, mm);
}


UINT rdpgfx_read_header(wStream* s, RDPGFX_HEADER* header)
{
	if (Stream_GetRemainingLength(s) < 8)
	{
		WLog_ERR(TAG, "calloc failed!");
		return CHANNEL_RC_NO_MEMORY;
	}

	Stream_Read_UINT16(s, header->cmdId);     /* cmdId (2 bytes) */
	Stream_Read_UINT16(s, header->flags);     /* flags (2 bytes) */
	Stream_Read_UINT32(s, header->pduLength); /* pduLength (4 bytes) */
	return CHANNEL_RC_OK;
}

Fixed input sanitation in rdpgfx_recv_solid_fill_pdu

The input rectangle must be checked for plausibility.

Thanks to Sunglin and HuanGMz of the Knownsec 404 security team and pangzi of pwnzen


UINT rdpgfx_write_header(wStream* s, const RDPGFX_HEADER* header)
{
	Stream_Write_UINT16(s, header->cmdId);     /* cmdId (2 bytes) */
	Stream_Write_UINT16(s, header->flags);     /* flags (2 bytes) */
	Stream_Write_UINT32(s, header->pduLength); /* pduLength (4 bytes) */
	return CHANNEL_RC_OK;
}


const char* rdpgfx_get_cmd_id_string(UINT16 cmdId)
{
	if (cmdId <= RDPGFX_CMDID_MAPSURFACETOSCALEDWINDOW)
		return RDPGFX_CMDID_STRINGS[cmdId];
	else
		return "RDPGFX_CMDID_UNKNOWN";
}


UINT rdpgfx_write_rect16(wStream* s, const RECTANGLE_16* rect16)
{
	Stream_Write_UINT16(s, rect16->left);   /* left (2 bytes) */
	Stream_Write_UINT16(s, rect16->top);    /* top (2 bytes) */
	Stream_Write_UINT16(s, rect16->right);  /* right (2 bytes) */
	Stream_Write_UINT16(s, rect16->bottom); /* bottom (2 bytes) */
	return CHANNEL_RC_OK;
}


const char* rdpgfx_get_codec_id_string(UINT16 codecId)
{
	switch (codecId)
	{
		case RDPGFX_CODECID_UNCOMPRESSED:
			return "RDPGFX_CODECID_UNCOMPRESSED";

		case RDPGFX_CODECID_CAVIDEO:
			return "RDPGFX_CODECID_CAVIDEO";

		case RDPGFX_CODECID_CLEARCODEC:
			return "RDPGFX_CODECID_CLEARCODEC";

		case RDPGFX_CODECID_PLANAR:
			return "RDPGFX_CODECID_PLANAR";

		case RDPGFX_CODECID_AVC420:
			return "RDPGFX_CODECID_AVC420";

		case RDPGFX_CODECID_AVC444:
			return "RDPGFX_CODECID_AVC444";

		case RDPGFX_CODECID_AVC444v2:
			return "RDPGFX_CODECID_AVC444v2";

		case RDPGFX_CODECID_ALPHA:
			return "RDPGFX_CODECID_ALPHA";

		case RDPGFX_CODECID_CAPROGRESSIVE:
			return "RDPGFX_CODECID_CAPROGRESSIVE";

		case RDPGFX_CODECID_CAPROGRESSIVE_V2:
			return "RDPGFX_CODECID_CAPROGRESSIVE_V2";
	}

	return "RDPGFX_CODECID_UNKNOWN";
}


UINT rdpgfx_write_color32(wStream* s, const RDPGFX_COLOR32* color32)
{
	Stream_Write_UINT8(s, color32->B);  /* B (1 byte) */
	Stream_Write_UINT8(s, color32->G);  /* G (1 byte) */
	Stream_Write_UINT8(s, color32->R);  /* R (1 byte) */
	Stream_Write_UINT8(s, color32->XA); /* XA (1 byte) */
	return CHANNEL_RC_OK;
}


UINT rdpgfx_write_point16(wStream* s, const RDPGFX_POINT16* point16)
{
	Stream_Write_UINT16(s, point16->x); /* x (2 bytes) */
	Stream_Write_UINT16(s, point16->y); /* y (2 bytes) */
	return CHANNEL_RC_OK;
}


UINT rdpgfx_read_color32(wStream* s, RDPGFX_COLOR32* color32)
{
	if (Stream_GetRemainingLength(s) < 4)
	{
		WLog_ERR(TAG, "not enough data!");
		return ERROR_INVALID_DATA;
	}

	Stream_Read_UINT8(s, color32->B);  /* B (1 byte) */
	Stream_Read_UINT8(s, color32->G);  /* G (1 byte) */
	Stream_Read_UINT8(s, color32->R);  /* R (1 byte) */
	Stream_Read_UINT8(s, color32->XA); /* XA (1 byte) */
	return CHANNEL_RC_OK;
}


UINT rdpgfx_read_rect16(wStream* s, RECTANGLE_16* rect16)
{
	if (Stream_GetRemainingLength(s) < 8)
	{
		WLog_ERR(TAG, "not enough data!");
		return ERROR_INVALID_DATA;
	}

	Stream_Read_UINT16(s, rect16->left);   /* left (2 bytes) */
	Stream_Read_UINT16(s, rect16->top);    /* top (2 bytes) */
	Stream_Read_UINT16(s, rect16->right);  /* right (2 bytes) */
	Stream_Read_UINT16(s, rect16->bottom); /* bottom (2 bytes) */
	if (rect16->left >= rect16->right)
		return ERROR_INVALID_DATA;
	if (rect16->top >= rect16->bottom)
		return ERROR_INVALID_DATA;
	return CHANNEL_RC_OK;
}


UINT rdpgfx_read_point16(wStream* s, RDPGFX_POINT16* pt16)
{
	if (Stream_GetRemainingLength(s) < 4)
	{
		WLog_ERR(TAG, "not enough data!");
		return ERROR_INVALID_DATA;
	}

	Stream_Read_UINT16(s, pt16->x); /* x (2 bytes) */
	Stream_Read_UINT16(s, pt16->y); /* y (2 bytes) */
	return CHANNEL_RC_OK;
}


BOOL update_recv_play_sound(rdpUpdate* update, wStream* s)
{
	PLAY_SOUND_UPDATE play_sound;

	if (!update_read_play_sound(s, &play_sound))
		return FALSE;

	return IFCALLRESULT(FALSE, update->PlaySound, update->context, &play_sound);
}

Fixed oob read in update_recv

properly use update_type_to_string to print update type.
Thanks to hac425 CVE-2020-11019


POINTER_CACHED_UPDATE* update_read_pointer_cached(rdpUpdate* update, wStream* s)
{
	POINTER_CACHED_UPDATE* pointer = calloc(1, sizeof(POINTER_CACHED_UPDATE));

	if (!pointer)
		goto fail;

	if (Stream_GetRemainingLength(s) < 2)
		goto fail;

	Stream_Read_UINT16(s, pointer->cacheIndex); /* cacheIndex (2 bytes) */
	return pointer;
fail:
	free_pointer_cached_update(update->context, pointer);
	return NULL;
}