/*

 * Copyright (C) 2013 Colin Walters <walters@verbum.org>

 *

 * SPDX-License-Identifier: LGPL-2.0+

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, write to the

 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,

 * Boston, MA 02111-1307, USA.

 */

#include "config.h"

#include "otutil.h"

#include "ostree-repo-private.h"

#include "ostree-linuxfsutil.h"

#include "ostree-sysroot-private.h"

/* @deploydir_dfd: Directory FD for ostree/deploy

 * @osname: Target osname

 * @inout_deployments: All deployments in this subdir will be appended to this array

 */

gboolean

_ostree_sysroot_list_deployment_dirs_for_os (int                  deploydir_dfd,

                                             const char          *osname,

                                             GPtrArray           *inout_deployments,

                                             GCancellable        *cancellable,

                                             GError             **error)

{

  g_auto(GLnxDirFdIterator) dfd_iter = { 0, };

  gboolean exists;

  const char *osdeploy_path = glnx_strjoina (osname, "/deploy");

  if (!ot_dfd_iter_init_allow_noent (deploydir_dfd, osdeploy_path, &dfd_iter, &exists, error))

    return FALSE;

  if (!exists)

    return TRUE;

  while (TRUE)

    {

      struct dirent *dent;

      if (!glnx_dirfd_iterator_next_dent_ensure_dtype (&dfd_iter, &dent, cancellable, error))

        return FALSE;

      if (dent == NULL)

        break;

      if (dent->d_type != DT_DIR)

        continue;

      g_autofree char *csum = NULL;

      gint deployserial;

      if (!_ostree_sysroot_parse_deploy_path_name (dent->d_name, &csum, &deployserial, error))

        return FALSE;

      g_ptr_array_add (inout_deployments, ostree_deployment_new (-1, osname, csum, deployserial, NULL, -1));

    }

  return TRUE;

}

/* Return in @out_deployments a new array of OstreeDeployment loaded from the

 * filesystem state.

 */

static gboolean

list_all_deployment_directories (OstreeSysroot       *self,

                                 GPtrArray          **out_deployments,

                                 GCancellable        *cancellable,

                                 GError             **error)

{

  g_autoptr(GPtrArray) ret_deployments =

    g_ptr_array_new_with_free_func (g_object_unref);

  g_auto(GLnxDirFdIterator) dfd_iter = { 0, };

  gboolean exists;

  if (!ot_dfd_iter_init_allow_noent (self->sysroot_fd, "ostree/deploy", &dfd_iter, &exists, error))

    return FALSE;

  if (!exists)

    return TRUE;

  while (TRUE)

    {

      struct dirent *dent;

      if (!glnx_dirfd_iterator_next_dent_ensure_dtype (&dfd_iter, &dent, cancellable, error))

        return FALSE;

      if (dent == NULL)

        break;

      if (dent->d_type != DT_DIR)

        continue;

      if (!_ostree_sysroot_list_deployment_dirs_for_os (dfd_iter.fd, dent->d_name,

                                                        ret_deployments,

                                                        cancellable, error))

        return FALSE;

    }

  ot_transfer_out_value (out_deployments, &ret_deployments);

  return TRUE;

}

static gboolean

parse_bootdir_name (const char *name,

                    char      **out_osname,

                    char      **out_csum)

{

  const char *lastdash;

  if (out_osname)

    *out_osname = NULL;

  if (out_csum)

    *out_csum = NULL;

  lastdash = strrchr (name, '-');

  if (!lastdash)

    return FALSE;

  if (!ostree_validate_checksum_string (lastdash + 1, NULL))

    return FALSE;

  if (out_osname)

    *out_osname = g_strndup (name, lastdash - name);

  if (out_csum)

    *out_csum = g_strdup (lastdash + 1);

  return TRUE;

}

static gboolean

list_all_boot_directories (OstreeSysroot       *self,

                           GPtrArray          **out_bootdirs,

                           GCancellable        *cancellable,

                           GError             **error)

{

  gboolean ret = FALSE;

  g_autoptr(GFile) boot_ostree = NULL;

  g_autoptr(GPtrArray) ret_bootdirs = NULL;

  GError *temp_error = NULL;

  boot_ostree = g_file_resolve_relative_path (self->path, "boot/ostree");

  ret_bootdirs = g_ptr_array_new_with_free_func (g_object_unref);

  g_autoptr(GFileEnumerator) dir_enum =

    g_file_enumerate_children (boot_ostree, OSTREE_GIO_FAST_QUERYINFO,

                               G_FILE_QUERY_INFO_NOFOLLOW_SYMLINKS,

                               cancellable, &temp_error);

  if (!dir_enum)

    {

      if (g_error_matches (temp_error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND))

        {

          g_clear_error (&temp_error);

          goto done;

        } 

      else

        {

          g_propagate_error (error, temp_error);

          goto out;

        }

    }

  while (TRUE)

    {

      GFileInfo *file_info = NULL;

      GFile *child = NULL;

      const char *name;

      if (!g_file_enumerator_iterate (dir_enum, &file_info, &child,

                                      NULL, error))

        goto out;

      if (file_info == NULL)

        break;

      if (g_file_info_get_file_type (file_info) != G_FILE_TYPE_DIRECTORY)

        continue;

      /* Only look at directories ending in -CHECKSUM; nothing else

       * should be in here, but let's be conservative.

       */

      name = g_file_info_get_name (file_info);

      if (!parse_bootdir_name (name, NULL, NULL))

        continue;

      g_ptr_array_add (ret_bootdirs, g_object_ref (child));

    }

 done:

  ret = TRUE;

  ot_transfer_out_value (out_bootdirs, &ret_bootdirs);

 out:

  return ret;

}

/* A sysroot has at most one active "boot version" (pair of version,subversion)

 * out of a total of 4 possible. This function deletes from the filesystem the 3

 * other versions that aren't active.

 */

static gboolean

cleanup_other_bootversions (OstreeSysroot       *self,

                            GCancellable        *cancellable,

                            GError             **error)

{

  const int cleanup_bootversion = self->bootversion == 0 ? 1 : 0;

  const int cleanup_subbootversion = self->subbootversion == 0 ? 1 : 0;

  /* Reusable buffer for path */

  g_autoptr(GString) buf = g_string_new ("");

  /* These directories are for the other major version */

  g_string_truncate (buf, 0); g_string_append_printf (buf, "boot/loader.%d", cleanup_bootversion);

  if (!glnx_shutil_rm_rf_at (self->sysroot_fd, buf->str, cancellable, error))

    return FALSE;

  g_string_truncate (buf, 0); g_string_append_printf (buf, "ostree/boot.%d", cleanup_bootversion);

  if (!glnx_shutil_rm_rf_at (self->sysroot_fd, buf->str, cancellable, error))

    return FALSE;

  g_string_truncate (buf, 0); g_string_append_printf (buf, "ostree/boot.%d.0", cleanup_bootversion);

  if (!glnx_shutil_rm_rf_at (self->sysroot_fd, buf->str, cancellable, error))

    return FALSE;

  g_string_truncate (buf, 0); g_string_append_printf (buf, "ostree/boot.%d.1", cleanup_bootversion);

  if (!glnx_shutil_rm_rf_at (self->sysroot_fd, buf->str, cancellable, error))

    return FALSE;

  /* And finally the other subbootversion */

  g_string_truncate (buf, 0); g_string_append_printf (buf, "ostree/boot.%d.%d", self->bootversion, cleanup_subbootversion);

  if (!glnx_shutil_rm_rf_at (self->sysroot_fd, buf->str, cancellable, error))

    return FALSE;

  return TRUE;

}

/* Delete a deployment directory */

gboolean

_ostree_sysroot_rmrf_deployment (OstreeSysroot *self,

                                 OstreeDeployment *deployment,

                                 GCancellable  *cancellable,

                                 GError       **error)

{

  g_autofree char *origin_relpath = ostree_deployment_get_origin_relpath (deployment);

  g_autofree char *deployment_path = ostree_sysroot_get_deployment_dirpath (self, deployment);

  struct stat stbuf;

  glnx_autofd int deployment_fd = -1;

  if (!glnx_opendirat (self->sysroot_fd, deployment_path, TRUE,

                       &deployment_fd, error))

    return FALSE;

  if (!glnx_fstat (deployment_fd, &stbuf, error))

    return FALSE;

  /* This shouldn't happen, because higher levels should

   * disallow having the booted deployment not in the active

   * deployment list, but let's be extra safe. */

  if (stbuf.st_dev == self->root_device &&

      stbuf.st_ino == self->root_inode)

    return TRUE;

  /* This deployment wasn't referenced, so delete it */

  if (!_ostree_linuxfs_fd_alter_immutable_flag (deployment_fd, FALSE,

                                                cancellable, error))

    return FALSE;

  if (!glnx_shutil_rm_rf_at (self->sysroot_fd, origin_relpath, cancellable, error))

    return FALSE;

  if (!glnx_shutil_rm_rf_at (self->sysroot_fd, deployment_path, cancellable, error))

    return FALSE;

  return TRUE;

}

/* As the bootloader configuration changes, we will have leftover deployments

 * on disk.  This function deletes all deployments which aren't actively

 * referenced.

 */

static gboolean

cleanup_old_deployments (OstreeSysroot       *self,

                         GCancellable        *cancellable,

                         GError             **error)

{

  /* Gather the device/inode of the rootfs, so we can double

   * check we won't delete it.

   */

  struct stat root_stbuf;

  if (!glnx_fstatat (AT_FDCWD, "/", &root_stbuf, 0, error))

    return FALSE;

  /* Load all active deployments referenced by bootloader configuration. */

  g_autoptr(GHashTable) active_deployment_dirs =

    g_hash_table_new_full (g_str_hash, (GEqualFunc)g_str_equal, g_free, NULL);

  g_autoptr(GHashTable) active_boot_checksums =

    g_hash_table_new_full (g_str_hash, (GEqualFunc)g_str_equal, g_free, NULL);

  for (guint i = 0; i < self->deployments->len; i++)

    {

      OstreeDeployment *deployment = self->deployments->pdata[i];

      char *deployment_path = ostree_sysroot_get_deployment_dirpath (self, deployment);

      char *bootcsum = g_strdup (ostree_deployment_get_bootcsum (deployment));

      /* Transfer ownership */

      g_hash_table_replace (active_deployment_dirs, deployment_path, deployment_path);

      g_hash_table_replace (active_boot_checksums, bootcsum, bootcsum);

    }

  /* Find all deployment directories, both active and inactive */

  g_autoptr(GPtrArray) all_deployment_dirs = NULL;

  if (!list_all_deployment_directories (self, &all_deployment_dirs,

                                        cancellable, error))

    return FALSE;

  g_assert (all_deployment_dirs); /* Pacify static analysis */

  for (guint i = 0; i < all_deployment_dirs->len; i++)

    {

      OstreeDeployment *deployment = all_deployment_dirs->pdata[i];

      g_autofree char *deployment_path = ostree_sysroot_get_deployment_dirpath (self, deployment);

      if (g_hash_table_lookup (active_deployment_dirs, deployment_path))

        continue;

      if (!_ostree_sysroot_rmrf_deployment (self, deployment, cancellable, error))

        return FALSE;

    }

  /* Clean up boot directories */

  g_autoptr(GPtrArray) all_boot_dirs = NULL;

  if (!list_all_boot_directories (self, &all_boot_dirs,

                                  cancellable, error))

    return FALSE;

  for (guint i = 0; i < all_boot_dirs->len; i++)

    {

      GFile *bootdir = all_boot_dirs->pdata[i];

      g_autofree char *osname = NULL;

      g_autofree char *bootcsum = NULL;

      if (!parse_bootdir_name (glnx_basename (gs_file_get_path_cached (bootdir)),

                               &osname, &bootcsum))

        g_assert_not_reached ();

      if (g_hash_table_lookup (active_boot_checksums, bootcsum))

        continue;

      if (!glnx_shutil_rm_rf_at (AT_FDCWD, gs_file_get_path_cached (bootdir), cancellable, error))

        return FALSE;

    }

  return TRUE;

}

/* Delete the ref bindings for a non-active boot version */

static gboolean

cleanup_ref_prefix (OstreeRepo         *repo,

                    int                 bootversion,

                    int                 subbootversion,

                    GCancellable       *cancellable,

                    GError            **error)

{

  g_autofree char *prefix = g_strdup_printf ("ostree/%d/%d", bootversion, subbootversion);

  g_autoptr(GHashTable) refs = NULL;

  if (!ostree_repo_list_refs_ext (repo, prefix, &refs, OSTREE_REPO_LIST_REFS_EXT_NONE, cancellable, error))

    return FALSE;

  GLNX_HASH_TABLE_FOREACH (refs, const char *, ref)

    {

      if (!ostree_repo_set_ref_immediate (repo, NULL, ref, NULL, cancellable, error))

        return FALSE;

    }

  return TRUE;

}

/* libostree holds a ref for each deployment's exact checksum to avoid it being

 * GC'd even if the origin ref changes.  This function resets those refs

 * to match active deployments.

 */

static gboolean

generate_deployment_refs (OstreeSysroot       *self,

                          OstreeRepo          *repo,

                          int                  bootversion,

                          int                  subbootversion,

                          GPtrArray           *deployments,

                          GCancellable        *cancellable,

                          GError             **error)

{

  int cleanup_bootversion = (bootversion == 0) ? 1 : 0;

  int cleanup_subbootversion = (subbootversion == 0) ? 1 : 0;

  if (!cleanup_ref_prefix (repo, cleanup_bootversion, 0,

                           cancellable, error))

    return FALSE;

  if (!cleanup_ref_prefix (repo, cleanup_bootversion, 1,

                           cancellable, error))

    return FALSE;

  if (!cleanup_ref_prefix (repo, bootversion, cleanup_subbootversion,

                           cancellable, error))

    return FALSE;

  g_autoptr(_OstreeRepoAutoTransaction) txn =

    _ostree_repo_auto_transaction_start (repo, cancellable, error);

  if (!txn)

    return FALSE;

  for (guint i = 0; i < deployments->len; i++)

    {

      OstreeDeployment *deployment = deployments->pdata[i];

      g_autofree char *refname = g_strdup_printf ("ostree/%d/%d/%u",

                                               bootversion, subbootversion,

                                               i);

      ostree_repo_transaction_set_refspec (repo, refname, ostree_deployment_get_csum (deployment));

    }

  if (!ostree_repo_commit_transaction (repo, NULL, cancellable, error))

    return FALSE;

  return TRUE;

}

/**

 * ostree_sysroot_cleanup_prune_repo:

 * @sysroot: Sysroot

 * @options: Flags controlling pruning

 * @out_objects_total: (out): Number of objects found

 * @out_objects_pruned: (out): Number of objects deleted

 * @out_pruned_object_size_total: (out): Storage size in bytes of objects deleted

 * @cancellable: Cancellable

 * @error: Error

 *

 * Prune the system repository.  This is a thin wrapper

 * around ostree_repo_prune_from_reachable(); the primary

 * addition is that this function automatically gathers

 * all deployed commits into the reachable set.

 *

 * You generally want to at least set the `OSTREE_REPO_PRUNE_FLAGS_REFS_ONLY`

 * flag in @options.  A commit traversal depth of `0` is assumed.

 *

 * Locking: exclusive

 * Since: 2018.6

 */

gboolean

ostree_sysroot_cleanup_prune_repo (OstreeSysroot          *sysroot,

                                   OstreeRepoPruneOptions *options,

                                   gint                   *out_objects_total,

                                   gint                   *out_objects_pruned,

                                   guint64                *out_pruned_object_size_total,

                                   GCancellable           *cancellable,

                                   GError                **error)

{

  GLNX_AUTO_PREFIX_ERROR ("Pruning system repository", error);

  OstreeRepo *repo = ostree_sysroot_repo (sysroot);

  const guint depth = 0; /* Historical default */

  if (!_ostree_sysroot_ensure_writable (sysroot, error))

    return FALSE;

  /* Hold an exclusive lock by default across gathering refs and doing

   * the prune.

   */

  g_autoptr(OstreeRepoAutoLock) lock =

    _ostree_repo_auto_lock_push (repo, OSTREE_REPO_LOCK_EXCLUSIVE, cancellable, error);

  if (!lock)

    return FALSE;

  /* Ensure reachable has refs, but default to depth 0.  This is

   * what we've always done for the system repo, but perhaps down

   * the line we could add a depth flag to the repo config or something?

   */

  if (!ostree_repo_traverse_reachable_refs (repo, depth, options->reachable, cancellable, error))

    return FALSE;

  /* Since ostree was created we've been generating "deployment refs" in

   * generate_deployment_refs() that look like ostree/0/1 etc. to ensure that

   * anything doing a direct prune won't delete commits backing deployments.

   * This bit might allow us to eventually drop that behavior, although we'd

   * have to be very careful to ensure that all software is updated to use

   * `ostree_sysroot_cleanup_prune_repo()`.

   */

  for (guint i = 0; i < sysroot->deployments->len; i++)

    {

      const char *checksum = ostree_deployment_get_csum (sysroot->deployments->pdata[i]);

      if (!ostree_repo_traverse_commit_union (repo, checksum, depth, options->reachable,

                                              cancellable, error))

        return FALSE;

    }

  if (!ostree_repo_prune_from_reachable (repo, options,

                                         out_objects_total, out_objects_pruned,

                                         out_pruned_object_size_total,

                                         cancellable, error))

    return FALSE;

  return TRUE;

}

/**

 * ostree_sysroot_cleanup:

 * @self: Sysroot

 * @cancellable: Cancellable

 * @error: Error

 *

 * Delete any state that resulted from a partially completed

 * transaction, such as incomplete deployments.

 */

gboolean

ostree_sysroot_cleanup (OstreeSysroot       *self,

                        GCancellable        *cancellable,

                        GError             **error)

{

  return _ostree_sysroot_cleanup_internal (self, TRUE, cancellable, error);

}

/**

 * ostree_sysroot_prepare_cleanup:

 * @self: Sysroot

 * @cancellable: Cancellable

 * @error: Error

 *

 * Like ostree_sysroot_cleanup() in that it cleans up incomplete deployments

 * and old boot versions, but does NOT prune the repository.

 */

gboolean

ostree_sysroot_prepare_cleanup (OstreeSysroot  *self,

                                GCancellable   *cancellable,

                                GError        **error)

{

  return _ostree_sysroot_cleanup_internal (self, FALSE, cancellable, error);

}

gboolean

_ostree_sysroot_cleanup_internal (OstreeSysroot              *self,

                                  gboolean                    do_prune_repo,

                                  GCancellable               *cancellable,

                                  GError                    **error)

{

  g_return_val_if_fail (OSTREE_IS_SYSROOT (self), FALSE);

  g_return_val_if_fail (self->loadstate == OSTREE_SYSROOT_LOAD_STATE_LOADED, FALSE);

  if (!_ostree_sysroot_ensure_writable (self, error))

    return FALSE;

  if (!cleanup_other_bootversions (self, cancellable, error))

    return glnx_prefix_error (error, "Cleaning bootversions");

  if (!cleanup_old_deployments (self, cancellable, error))

    return glnx_prefix_error (error, "Cleaning deployments");

  OstreeRepo *repo = ostree_sysroot_repo (self);

  if (!generate_deployment_refs (self, repo,

                                 self->bootversion,

                                 self->subbootversion,

                                 self->deployments,

                                 cancellable, error))

    return glnx_prefix_error (error, "Generating deployment refs");

  if (do_prune_repo)

    {

      gint n_objects_total;

      gint n_objects_pruned;

      guint64 freed_space;

      g_autoptr(GHashTable) reachable = ostree_repo_traverse_new_reachable ();

      OstreeRepoPruneOptions opts = { OSTREE_REPO_PRUNE_FLAGS_REFS_ONLY, reachable };

      if (!ostree_sysroot_cleanup_prune_repo (self, &opts, &n_objects_total,

                                              &n_objects_pruned, &freed_space,

                                              cancellable, error))

        return FALSE;

      /* TODO remove printf in library */

      if (freed_space > 0)

        {

          g_autofree char *freed_space_str = g_format_size_full (freed_space, 0);

          g_print ("Freed objects: %s\n", freed_space_str);

        }

    }

  return TRUE;

}