path: root/pigeonhole/src/lib-sieve/sieve-storage.c

/* Copyright (c) 2002-2018 Pigeonhole authors, see the included COPYING file
 */

#include "lib.h"
#include "array.h"
#include "str-sanitize.h"
#include "home-expand.h"
#include "eacces-error.h"
#include "mkdir-parents.h"
#include "ioloop.h"

#include "sieve-common.h"
#include "sieve-settings.h"
#include "sieve-error-private.h"

#include "sieve-script-private.h"
#include "sieve-storage-private.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <time.h>
#include <utime.h>

#define CRITICAL_MSG \
  "Internal error occurred. Refer to server log for more information."
#define CRITICAL_MSG_STAMP CRITICAL_MSG " [%Y-%m-%d %H:%M:%S]"

struct event_category event_category_sieve_storage = {
	.parent = &event_category_sieve,
	.name = "sieve-storage",
};

/*
 * Storage class
 */

struct sieve_storage_class_registry {
	ARRAY_TYPE(sieve_storage_class) storage_classes;
};

void sieve_storages_init(struct sieve_instance *svinst)
{
	svinst->storage_reg = p_new(svinst->pool,
				    struct sieve_storage_class_registry, 1);
	p_array_init(&svinst->storage_reg->storage_classes, svinst->pool, 8);

	sieve_storage_class_register(svinst, &sieve_file_storage);
	sieve_storage_class_register(svinst, &sieve_dict_storage);
	sieve_storage_class_register(svinst, &sieve_ldap_storage);
}

void sieve_storages_deinit(struct sieve_instance *svinst ATTR_UNUSED)
{
	/* nothing yet */
}

void sieve_storage_class_register(struct sieve_instance *svinst,
				  const struct sieve_storage *storage_class)
{
	struct sieve_storage_class_registry *reg = svinst->storage_reg;
	const struct sieve_storage *old_class;

	old_class = sieve_storage_find_class(svinst,
					     storage_class->driver_name);
	if (old_class != NULL) {
		if (old_class->v.alloc == NULL) {
			/* replacing a "support not compiled in" storage class
			 */
			sieve_storage_class_unregister(svinst, old_class);
		} else {
			i_panic("sieve_storage_class_register(%s): "
				"Already registered",
				storage_class->driver_name);
		}
	}

	array_append(&reg->storage_classes, &storage_class, 1);
}

void sieve_storage_class_unregister(struct sieve_instance *svinst,
				    const struct sieve_storage *storage_class)
{
	struct sieve_storage_class_registry *reg = svinst->storage_reg;
	const struct sieve_storage *const *classes;
	unsigned int i, count;

	classes = array_get(&reg->storage_classes, &count);
	for (i = 0; i < count; i++) {
		if (classes[i] == storage_class) {
			array_delete(&reg->storage_classes, i, 1);
			break;
		}
	}
}

const struct sieve_storage *
sieve_storage_find_class(struct sieve_instance *svinst, const char *name)
{
	struct sieve_storage_class_registry *reg = svinst->storage_reg;
	const struct sieve_storage *const *classes;
	unsigned int i, count;

	i_assert(name != NULL);

	classes = array_get(&reg->storage_classes, &count);
	for (i = 0; i < count; i++) {
		if (strcasecmp(classes[i]->driver_name, name) == 0)
			return classes[i];
	}
	return NULL;
}

/*
 * Storage instance
 */

static const char *split_next_arg(const char *const **_args)
{
	const char *const *args = *_args;
	const char *str = args[0];

	/* join arguments for escaped ";" separator */

	args++;
	while (*args != NULL && **args == '\0') {
		args++;
		if (*args == NULL) {
			/* string ends with ";", just ignore it. */
			break;
		}
		str = t_strconcat(str, ";", *args, NULL);
		args++;
	}
	*_args = args;
	return str;
}

static int
sieve_storage_driver_parse(struct sieve_instance *svinst, const char **data,
			   const struct sieve_storage **driver_r)
{
	const struct sieve_storage *storage_class = NULL;
	const char *p;

	p = strchr(*data, ':');
	if (p == NULL)
		return 0;

	/* Lookup storage driver */
	T_BEGIN {
		const char *driver;

		driver = t_strdup_until(*data, p);
		*data = p+1;

		storage_class = sieve_storage_find_class(svinst, driver);
		if (storage_class == NULL) {
			e_error(svinst->event,
				"Unknown storage driver module `%s'",
				driver);
		} else if (storage_class->v.alloc == NULL) {
			e_error(svinst->event,
				"Support not compiled in for storage driver `%s'",
				driver);
			storage_class = NULL;
		}
	} T_END;

	*driver_r = storage_class;
	return (storage_class == NULL ? -1 : 1);
}

static int
sieve_storage_data_parse(struct sieve_storage *storage, const char *data,
			 const char **location_r, const char *const **options_r)
{
	ARRAY_TYPE(const_string) options;
	const char *const *tmp;

	if (*data == '\0') {
		*options_r = NULL;
		*location_r = data;
		return 0;
	}

	/* <location> */
	tmp = t_strsplit(data, ";");
	*location_r = split_next_arg(&tmp);

	if (options_r != NULL) {
		t_array_init(&options, 8);

		/* [<option> *(';' <option>)] */
		while (*tmp != NULL) {
			const char *option = split_next_arg(&tmp);

			if (strncasecmp(option, "name=", 5) == 0) {
				if (option[5] == '\0') {
					e_error(storage->event,
						"Failed to parse storage location: "
						"Empty name not allowed");
					return -1;
				}

				if (storage->script_name == NULL) {
					if (!sieve_script_name_is_valid(option+5)) {
						e_error(storage->event,
							"Failed to parse storage location: "
							"Invalid script name `%s'.",
							str_sanitize(option+5, 80));
						return -1;
					}
					storage->script_name = p_strdup(storage->pool, option+5);
				}

			} else if (strncasecmp(option, "bindir=", 7) == 0) {
				const char *bin_dir = option+7;

				if (bin_dir[0] == '\0') {
					e_error(storage->event,
						"Failed to parse storage location: "
						"Empty bindir not allowed");
					return -1;
				}

				if (bin_dir[0] == '~') {
					/* home-relative path. change to absolute. */
					const char *home = sieve_environment_get_homedir(storage->svinst);

					if (home != NULL) {
						bin_dir = home_expand_tilde(bin_dir, home);
					} else if (bin_dir[1] == '/' || bin_dir[1] == '\0') {
						e_error(storage->event,
							"Failed to parse storage location: "
							"bindir is relative to home directory (~/), "
							"but home directory cannot be determined");
						return -1;
					}
				}

				storage->bin_dir = p_strdup(storage->pool, bin_dir);
			} else {
				array_append(&options, &option, 1);
			}
		}

		(void)array_append_space(&options);
		*options_r = array_idx(&options, 0);
	}

	return 0;
}

struct event *
sieve_storage_event_create(struct sieve_instance *svinst,
			   const struct sieve_storage *storage_class)
{
	struct event *event;

	event = event_create(svinst->event);
	event_add_category(event, &event_category_sieve_storage);
	event_add_str(event, "driver", storage_class->driver_name);
	event_set_append_log_prefix(
		event, t_strdup_printf("%s storage: ",
				       storage_class->driver_name));

	return event;
}

struct sieve_storage *
sieve_storage_alloc(struct sieve_instance *svinst, struct event *event,
		    const struct sieve_storage *storage_class, const char *data,
		    enum sieve_storage_flags flags, bool main)
{
	struct sieve_storage *storage;

	i_assert(storage_class->v.alloc != NULL);
	storage = storage_class->v.alloc();

	storage->storage_class = storage_class;
	storage->refcount = 1;
	storage->svinst = svinst;
	storage->flags = flags;
	storage->data = p_strdup_empty(storage->pool, data);
	storage->main_storage = main;

	if (event != NULL) {
		storage->event = event;
		event_ref(storage->event);
	} else {
		storage->event =
			sieve_storage_event_create(svinst, storage_class);
	}

	return storage;
}

static struct sieve_storage *
sieve_storage_init(struct sieve_instance *svinst,
		   const struct sieve_storage *storage_class, const char *data,
		   enum sieve_storage_flags flags, bool main,
		   enum sieve_error *error_r)
{
	struct sieve_storage *storage;
	const char *const *options;
	const char *location;
	struct event *event;
	enum sieve_error error;

	if (error_r != NULL)
		*error_r = SIEVE_ERROR_NONE;
	else
		error_r = &error;

	i_assert(storage_class->v.init != NULL);

	event = sieve_storage_event_create(svinst, storage_class);

	if ((flags & SIEVE_STORAGE_FLAG_SYNCHRONIZING) != 0 &&
	    !storage_class->allows_synchronization) {
		e_debug(event, "Storage does not support synchronization");
		*error_r = SIEVE_ERROR_NOT_POSSIBLE;
		event_unref(&event);
		return NULL;
	}

	if ((flags & SIEVE_STORAGE_FLAG_READWRITE) != 0 &&
	    storage_class->v.save_init == NULL) {
		e_error(event, "Storage does not support write access");
		*error_r = SIEVE_ERROR_TEMP_FAILURE;
		event_unref(&event);
		return NULL;
	}

	T_BEGIN {	
		storage = sieve_storage_alloc(svinst, event, storage_class,
					      data, flags, main);

		if (sieve_storage_data_parse(storage, data,
					     &location, &options) < 0) {
			*error_r = SIEVE_ERROR_TEMP_FAILURE;
			sieve_storage_unref(&storage);
			storage = NULL;
		} else {
			storage->location = p_strdup(storage->pool, location);

			event_add_str(event, "script_location",
				      storage->location);

			if (storage_class->v.init(storage, options,
						  error_r) < 0) {
				sieve_storage_unref(&storage);
				storage = NULL;
			}
		}
	} T_END;

	event_unref(&event);
	return storage;
}

struct sieve_storage *
sieve_storage_create(struct sieve_instance *svinst, const char *location,
		     enum sieve_storage_flags flags, enum sieve_error *error_r)
{
	const struct sieve_storage *storage_class;
	enum sieve_error error;
	const char *data;
	int ret;

	/* Dont use this function for creating a synchronizing storage */
	i_assert((flags & SIEVE_STORAGE_FLAG_SYNCHRONIZING) == 0);

	if (error_r != NULL)
		*error_r = SIEVE_ERROR_NONE;
	else
		error_r = &error;

	data = location;
	if ((ret = sieve_storage_driver_parse(svinst, &data,
					      &storage_class)) < 0) {
		*error_r = SIEVE_ERROR_TEMP_FAILURE;
		return NULL;
	}

	if (ret == 0)
		storage_class = &sieve_file_storage;

	return sieve_storage_init(svinst, storage_class, data, flags,
				  FALSE, error_r);
}

static struct sieve_storage *
sieve_storage_do_create_main(struct sieve_instance *svinst,
			     struct mail_user *user,
			     enum sieve_storage_flags flags,
			     enum sieve_error *error_r)
{
	struct sieve_storage *storage = NULL;
	const struct sieve_storage
		*sieve_class = NULL,
		*sieve_dir_class = NULL;
	const char *set_sieve, *set_sieve_dir;
	const char *data, *storage_path;
	unsigned long long int uint_setting;
	size_t size_setting;
	int ret;

	/* Sieve storage location */

	set_sieve = sieve_setting_get(svinst, "sieve");

	if (set_sieve != NULL) {
		if (*set_sieve == '\0') {
			/* disabled */
			e_debug(svinst->event, "storage: "
				"Personal storage is disabled (sieve=\"\")");
			*error_r = SIEVE_ERROR_NOT_FOUND;
			return NULL;
		}

		data = set_sieve;
		if ((ret = sieve_storage_driver_parse(svinst, &data,
						      &sieve_class)) < 0) {
			*error_r = SIEVE_ERROR_TEMP_FAILURE;
			return NULL;
		}

		if (ret > 0) {
			/* The normal case: explicit driver name */
			storage = sieve_storage_init(svinst, sieve_class, data,
						     flags, TRUE, error_r);
			if (storage == NULL)
				return NULL;
		}

		/* No driver name */
	}

	if (storage == NULL) {
		/* Script storage directory configuration (deprecated) */

		set_sieve_dir = sieve_setting_get(svinst, "sieve_dir");
		if (set_sieve_dir == NULL) {
			set_sieve_dir = sieve_setting_get(svinst,
							  "sieve_storage");
		}

		if (set_sieve_dir == NULL || *set_sieve_dir == '\0') {
			storage_path = "";
		} else {
			const char *p;

			/* Parse and check driver */
			storage_path = set_sieve_dir;
			if ((ret = sieve_storage_driver_parse(
				svinst, &storage_path, &sieve_dir_class)) < 0) {
				*error_r = SIEVE_ERROR_TEMP_FAILURE;
				return NULL;
			}

			if (ret > 0 && sieve_dir_class != &sieve_file_storage) {
				e_error(svinst->event, "storage: "
					"Cannot use deprecated sieve_dir= setting "
					"with `%s' driver for main Sieve storage",
					sieve_dir_class->driver_name);
			}

			/* Ignore any options */
			p = strchr(storage_path, ';');
			if (p != NULL)
				storage_path = t_strdup_until(storage_path, p);
		}

		storage = sieve_file_storage_init_legacy(svinst, set_sieve,
							 storage_path, flags,
							 error_r);
	}

	if (storage == NULL)
		return NULL;

	(void)sieve_storage_sync_init(storage, user);

	/* Get quota settings if storage driver provides none */

	if (storage->max_storage == 0 &&
	    sieve_setting_get_size_value(svinst, "sieve_quota_max_storage",
					 &size_setting)) {
		storage->max_storage = size_setting;
	}

	if (storage->max_scripts == 0 &&
	    sieve_setting_get_uint_value(svinst, "sieve_quota_max_scripts",
					 &uint_setting)) {
		storage->max_scripts = uint_setting;
	}

	if (storage->max_storage > 0) {
		e_debug(storage->event, "quota: "
			"Storage limit: %llu bytes",
			(unsigned long long int) storage->max_storage);
	}
	if (storage->max_scripts > 0) {
		e_debug(storage->event, "quota: "
			"Script count limit: %llu scripts",
			(unsigned long long int) storage->max_scripts);
	}
	return storage;
}

struct sieve_storage *
sieve_storage_create_main(struct sieve_instance *svinst, struct mail_user *user,
			  enum sieve_storage_flags flags,
			  enum sieve_error *error_r)
{
	struct sieve_storage *storage;
	const char *set_enabled, *set_default, *set_default_name;
	enum sieve_error error;

	if (error_r != NULL)
		*error_r = SIEVE_ERROR_NONE;
	else
		error_r = &error;

	/* Check whether Sieve is disabled for this user */
	if ((set_enabled = sieve_setting_get(svinst, "sieve_enabled")) != NULL &&
	    strcasecmp(set_enabled, "no") == 0) {
		e_debug(svinst->event,
			"Sieve is disabled for this user");
		*error_r = SIEVE_ERROR_NOT_POSSIBLE;
		return NULL;
	}

	/* Determine location for default script */
	set_default = sieve_setting_get(svinst, "sieve_default");
	if (set_default == NULL) {
		/* For backwards compatibility */
		set_default = sieve_setting_get(svinst, "sieve_global_path");
	}

	/* Attempt to locate user's main storage */
	storage = sieve_storage_do_create_main(svinst, user, flags, error_r);
	if (storage != NULL) {
		/* Success; record default script location for later use */
		storage->default_location =
			p_strdup_empty(storage->pool, set_default);

		set_default_name =
			sieve_setting_get(svinst, "sieve_default_name");
		if (set_default_name != NULL && *set_default_name != '\0' &&
		    !sieve_script_name_is_valid(set_default_name)) {
			e_error(storage->event,
				"Invalid script name `%s' for `sieve_default_name' setting.",
				str_sanitize(set_default_name, 80));
			set_default_name = NULL;
		}
		storage->default_name =
			p_strdup_empty(storage->pool, set_default_name);

		if (storage->default_location != NULL &&
			storage->default_name != NULL) {
			e_debug(storage->event,
				"Default script at `%s' is visible by name `%s'",
				storage->default_location, storage->default_name);
		}
	} else if (*error_r != SIEVE_ERROR_TEMP_FAILURE &&
		   (flags & SIEVE_STORAGE_FLAG_SYNCHRONIZING) == 0 &&
		   (flags & SIEVE_STORAGE_FLAG_READWRITE) == 0) {

		/* Failed; try using default script location
		   (not for temporary failures, read/write access, or dsync) */
		if (set_default == NULL) {
			e_debug(svinst->event, "storage: "
				"No default script location configured");
		} else {
			e_debug(svinst->event, "storage: "
				"Trying default script location `%s'",
				set_default);

			storage = sieve_storage_create(svinst, set_default, 0,
						       error_r);
			if (storage == NULL) {
				switch (*error_r) {
				case SIEVE_ERROR_NOT_FOUND:
					e_debug(svinst->event, "storage: "
						"Default script location `%s' not found",
						set_default);
					break;
				case SIEVE_ERROR_TEMP_FAILURE:
					e_error(svinst->event, "storage: "
						"Failed to access default script location `%s' "
						"(temporary failure)",
						set_default);
					break;
				default:
					e_error(svinst->event, "storage: "
						"Failed to access default script location `%s'",
						set_default);
					break;
				}
			}
		}
		if (storage != NULL)
			storage->is_default = TRUE;
	}
	return storage;
}

void sieve_storage_ref(struct sieve_storage *storage)
{
	storage->refcount++;
}

void sieve_storage_unref(struct sieve_storage **_storage)
{
	struct sieve_storage *storage = *_storage;

	i_assert(storage->refcount > 0);

	if (--storage->refcount != 0)
		return;

	if (storage->default_for != NULL) {
		i_assert(storage->is_default);
		sieve_storage_unref(&storage->default_for);
	}

	sieve_storage_sync_deinit(storage);

	if (storage->v.destroy != NULL)
		storage->v.destroy(storage);

	i_free(storage->error);
	event_unref(&storage->event);
	pool_unref(&storage->pool);
	*_storage = NULL;
}

int sieve_storage_setup_bindir(struct sieve_storage *storage, mode_t mode)
{
	const char *bin_dir = storage->bin_dir;
	struct stat st;

	if (bin_dir == NULL)
		return -1;

	if (stat(bin_dir, &st) == 0)
		return 0;

	if (errno == EACCES) {
		e_error(storage->event,
			"Failed to setup directory for binaries: "
			"%s",	eacces_error_get("stat", bin_dir));
		return -1;
	} else if (errno != ENOENT) {
		e_error(storage->event,
			"Failed to setup directory for binaries: "
			"stat(%s) failed: %m",
			bin_dir);
		return -1;
	}

	if (mkdir_parents(bin_dir, mode) == 0) {
		e_debug(storage->event,
			"Created directory for binaries: %s", bin_dir);
		return 1;
	}

	switch (errno) {
	case EEXIST:
		return 0;
	case ENOENT:
		e_error(storage->event,
			"Directory for binaries was deleted while it was being created");
		break;
	case EACCES:
		e_error(storage->event,
			"%s",	eacces_error_get_creating("mkdir_parents_chgrp", bin_dir));
		break;
	default:
		e_error(storage->event,
			"mkdir_parents_chgrp(%s) failed: %m", bin_dir);
		break;
	}

	return -1;
}

int sieve_storage_is_singular(struct sieve_storage *storage)
{
	if (storage->v.is_singular == NULL)
		return 1;
	return storage->v.is_singular(storage);
}

int sieve_storage_get_last_change(struct sieve_storage *storage,
				  time_t *last_change_r)
{
	i_assert(storage->v.get_last_change != NULL);
	return storage->v.get_last_change(storage, last_change_r);
}

void sieve_storage_set_modified(struct sieve_storage *storage, time_t mtime)
{
	if (storage->v.set_modified == NULL)
		return;

	storage->v.set_modified(storage, mtime);
}

/*
 * Script access
 */

static struct sieve_script *
sieve_storage_get_script_direct(struct sieve_storage *storage, const char *name,
				enum sieve_error *error_r)
{
	struct sieve_script *script;

	if (error_r != NULL)
		*error_r = SIEVE_ERROR_NONE;
	sieve_storage_clear_error(storage);

	/* Validate script name */
	if (name != NULL && !sieve_script_name_is_valid(name)) {
		sieve_storage_set_error(storage,
			SIEVE_ERROR_BAD_PARAMS,
			"Invalid script name `%s'.",
			str_sanitize(name, 80));
		if (error_r != NULL)
			*error_r = storage->error_code;
		return NULL;
	}

	i_assert(storage->v.get_script != NULL);
	script = storage->v.get_script(storage, name);
	return script;
}

struct sieve_script *
sieve_storage_get_script(struct sieve_storage *storage, const char *name,
			 enum sieve_error *error_r)
{
	struct sieve_instance *svinst = storage->svinst;
	struct sieve_script *script;

	script = sieve_storage_get_script_direct(storage, name, error_r);
	if (script == NULL) {
		/* Error */
		if (storage->error_code == SIEVE_ERROR_NOT_FOUND &&
		    (storage->flags & SIEVE_STORAGE_FLAG_SYNCHRONIZING) == 0 &&
		    storage->default_name != NULL &&
		    storage->default_location != NULL &&
		    strcmp(storage->default_name, name) == 0) {
			/* Not found; if this name maps to the default script,
			   try to access that instead */
			i_assert(*storage->default_location != '\0');

			e_debug(storage->event,
				"Trying default script instead");

			script = sieve_script_create(
				svinst,	storage->default_location, NULL,
				error_r);
			if (script != NULL) {
				script->storage->is_default = TRUE;
				script->storage->default_for = storage;
				sieve_storage_ref(storage);
			}

		} else if (error_r != NULL) {
			*error_r = storage->error_code;
		}
	}
	return script;
}

struct sieve_script *
sieve_storage_open_script(struct sieve_storage *storage, const char *name,
			  enum sieve_error *error_r)
{
	struct sieve_instance *svinst = storage->svinst;
	struct sieve_script *script;

	script = sieve_storage_get_script(storage, name, error_r);
	if (script == NULL)
		return NULL;

	if (sieve_script_open(script, error_r) >= 0)
		return script;

	/* Error */
	sieve_script_unref(&script);
	script = NULL;

	if (storage->error_code == SIEVE_ERROR_NOT_FOUND &&
	    (storage->flags & SIEVE_STORAGE_FLAG_SYNCHRONIZING) == 0 &&
	    storage->default_name != NULL &&
	    storage->default_location != NULL &&
	    strcmp(storage->default_name, name) == 0) {
		/* Not found; if this name maps to the default script,
		   try to open that instead */
		i_assert(*storage->default_location != '\0');

		e_debug(storage->event, "Trying default script instead");

		script = sieve_script_create_open(
			svinst, storage->default_location, NULL, error_r);
		if (script != NULL) {
			script->storage->is_default = TRUE;
			script->storage->default_for = storage;
			sieve_storage_ref(storage);
		}
	}
	return script;
}

static int
sieve_storage_check_script_direct(struct sieve_storage *storage,
				  const char *name, enum sieve_error *error_r)
				  ATTR_NULL(3)
{
	struct sieve_script *script;
	enum sieve_error error;
	int ret;

	if (error_r == NULL)
		error_r = &error;

	script = sieve_storage_get_script_direct(storage, name, error_r);
	if (script == NULL)
		return (*error_r == SIEVE_ERROR_NOT_FOUND ? 0 : -1);

	ret = sieve_script_open(script, error_r);
	sieve_script_unref(&script);
	return (ret >= 0 ? 1 : (*error_r == SIEVE_ERROR_NOT_FOUND ? 0 : -1));
}

int sieve_storage_check_script(struct sieve_storage *storage, const char *name,
			       enum sieve_error *error_r)
{
	struct sieve_script *script;
	enum sieve_error error;

	if (error_r == NULL)
		error_r = &error;

	script = sieve_storage_open_script(storage, name, error_r);
	if (script == NULL)
		return (*error_r == SIEVE_ERROR_NOT_FOUND ? 0 : -1);

	sieve_script_unref(&script);
	return 1;
}

/*
 * Script sequence
 */

struct sieve_script_sequence *
sieve_storage_get_script_sequence(struct sieve_storage *storage,
				  enum sieve_error *error_r)
{
	enum sieve_error error;

	if (error_r != NULL)
		*error_r = SIEVE_ERROR_NONE;
	else
		error_r = &error;

	i_assert(storage->v.get_script_sequence != NULL);
	return storage->v.get_script_sequence(storage, error_r);
}

/*
 * Active script
 */

static int
sieve_storage_active_script_do_get_name(struct sieve_storage *storage,
					const char **name_r, bool *default_r)
					ATTR_NULL(3)
{
	struct sieve_instance *svinst = storage->svinst;
	enum sieve_error error;
	int ret;

	if (default_r != NULL)
		*default_r = FALSE;

	i_assert(storage->v.active_script_get_name != NULL);
	ret = storage->v.active_script_get_name(storage, name_r);

	if (ret != 0 ||
	    (storage->flags & SIEVE_STORAGE_FLAG_SYNCHRONIZING) != 0 ||
	    storage->default_location == NULL ||
	    storage->default_name == NULL) {
		return ret;
	}

	*name_r = storage->default_name;

	ret = sieve_script_check(svinst, storage->default_location,
				 NULL, &error);
	if (ret <= 0)
		return ret;

	if (default_r != NULL)
		*default_r = TRUE;
	return 1;
}

int sieve_storage_active_script_get_name(struct sieve_storage *storage,
					 const char **name_r)
{
	return sieve_storage_active_script_do_get_name(storage, name_r, NULL);
}

int sieve_storage_active_script_is_default(struct sieve_storage *storage)
{
	const char *name;
	bool is_default = FALSE;
	int ret;

	ret = sieve_storage_active_script_do_get_name(storage, &name,
						      &is_default);
	return (ret < 0 ? -1 : (is_default ? 1 : 0));
}

struct sieve_script *
sieve_storage_active_script_open(struct sieve_storage *storage,
				 enum sieve_error *error_r)
{
	struct sieve_instance *svinst = storage->svinst;
	struct sieve_script *script;

	i_assert(storage->v.active_script_open != NULL);
	script = storage->v.active_script_open(storage);

	if (script != NULL ||
	    (storage->flags & SIEVE_STORAGE_FLAG_SYNCHRONIZING) != 0 ||
	    storage->default_location == NULL) {
		if (error_r != NULL)
			*error_r = storage->error_code;
		return script;
	}

	/* Try default script location */
	script = sieve_script_create_open(svinst, storage->default_location,
					  NULL, error_r);
	if (script != NULL) {
		script->storage->is_default = TRUE;
		script->storage->default_for = storage;
		sieve_storage_ref(storage);
	}
	return script;
}

int sieve_storage_deactivate(struct sieve_storage *storage, time_t mtime)
{
	int ret;

	i_assert((storage->flags & SIEVE_STORAGE_FLAG_READWRITE) != 0);

	i_assert(storage->v.deactivate != NULL);
	ret = storage->v.deactivate(storage);

	if (ret >= 0) {
		struct event_passthrough *e =
			event_create_passthrough(storage->event)->
			set_name("sieve_storage_deactivated");
		e_debug(e->event(), "Storage activated");

		sieve_storage_set_modified(storage, mtime);
		(void)sieve_storage_sync_deactivate(storage);
	} else {
		struct event_passthrough *e =
			event_create_passthrough(storage->event)->
			add_str("error", storage->error)->
			set_name("sieve_storage_deactivated");
		e_debug(e->event(), "Failed to deactivate storage: %s",
			storage->error);
	}

	return ret;
}

int sieve_storage_active_script_get_last_change(struct sieve_storage *storage,
						time_t *last_change_r)
{
	i_assert(storage->v.active_script_get_last_change != NULL);

	return storage->v.active_script_get_last_change(storage, last_change_r);
}

/*
 * Listing scripts
 */

struct sieve_storage_list_context *
sieve_storage_list_init(struct sieve_storage *storage)
{
	struct sieve_storage_list_context *lctx;

	i_assert(storage->v.list_init != NULL);
	lctx = storage->v.list_init(storage);

	if (lctx != NULL)
		lctx->storage = storage;

	return lctx;
}

const char *
sieve_storage_list_next(struct sieve_storage_list_context *lctx, bool *active_r)
{
	struct sieve_storage *storage = lctx->storage;
	struct sieve_instance *svinst = storage->svinst;
	const char *scriptname;
	bool have_default, script_active = FALSE;

	have_default = (storage->default_name != NULL &&
			storage->default_location != NULL &&
			(storage->flags &
			 SIEVE_STORAGE_FLAG_SYNCHRONIZING) == 0);

	i_assert(storage->v.list_next != NULL);
	scriptname = storage->v.list_next(lctx, &script_active);

	i_assert(!script_active || !lctx->seen_active);
	if (script_active)
		lctx->seen_active = TRUE;

	if (scriptname != NULL) {
		/* Remember when we see that the storage has its own script for
		   default */
		if (have_default &&
		    strcmp(scriptname, storage->default_name) == 0)
			lctx->seen_default = TRUE;

	} else if (have_default && !lctx->seen_default &&
		sieve_script_check(svinst, storage->default_location,
				   NULL, NULL) > 0) {

		/* Return default script at the end if it was not listed
		   thus far (storage backend has no script under default
		   name) */
		scriptname = storage->default_name;
		lctx->seen_default = TRUE;

		/* Mark default as active if no normal script is active */
		if (!lctx->seen_active) {
			script_active = TRUE;
			lctx->seen_active = TRUE;
		}
	}

	if (active_r != NULL)
		*active_r = script_active;
	return scriptname;
}

int sieve_storage_list_deinit(struct sieve_storage_list_context **_lctx)
{
	struct sieve_storage_list_context *lctx = *_lctx;
	struct sieve_storage *storage = lctx->storage;
	int ret;

	i_assert(storage->v.list_deinit != NULL);
	ret = storage->v.list_deinit(lctx);

	*_lctx = NULL;
	return ret;
}

/*
 * Saving scripts
 */

static struct event *
sieve_storage_save_create_event(struct sieve_storage *storage,
				const char *scriptname) ATTR_NULL(2)
{
	struct event *event;

	event = event_create(storage->event);
	event_add_str(event, "script_name", scriptname);
	if (scriptname == NULL) {
		event_set_append_log_prefix(event, "save: ");
	} else {
		event_set_append_log_prefix(
			event, t_strdup_printf("script `%s': save: ",
					       scriptname));
	}

	return event;
}

static void sieve_storage_save_cleanup(struct sieve_storage_save_context *sctx)
{
	if (sctx->scriptobject != NULL)
		sieve_script_unref(&sctx->scriptobject);
}

static void sieve_storage_save_deinit(struct sieve_storage_save_context **_sctx)
{
	struct sieve_storage_save_context *sctx = *_sctx;

	*_sctx = NULL;
	if (sctx == NULL)
		return;

	sieve_storage_save_cleanup(sctx);
	event_unref(&sctx->event);
	pool_unref(&sctx->pool);
}

struct sieve_storage_save_context *
sieve_storage_save_init(struct sieve_storage *storage, const char *scriptname,
			struct istream *input)
{
	struct sieve_storage_save_context *sctx;

	if (scriptname != NULL) {
		/* Validate script name */
		if (!sieve_script_name_is_valid(scriptname)) {
			sieve_storage_set_error(storage,
				SIEVE_ERROR_BAD_PARAMS,
				"Invalid Sieve script name `%s'.",
				str_sanitize(scriptname, 80));
			return NULL;
		}
	}

	i_assert((storage->flags & SIEVE_STORAGE_FLAG_READWRITE) != 0);

	i_assert(storage->v.save_alloc != NULL);
	sctx = storage->v.save_alloc(storage);
	sctx->storage = storage;

	sctx->event = sieve_storage_save_create_event(storage, scriptname);

	struct event_passthrough *e =
		event_create_passthrough(sctx->event)->
		set_name("sieve_storage_save_started");
	e_debug(e->event(), "Started saving script");

	i_assert(storage->v.save_init != NULL);
	if ((storage->v.save_init(sctx, scriptname, input)) < 0) {
		struct event_passthrough *e =
			event_create_passthrough(sctx->event)->
			add_str("error", storage->error)->
			set_name("sieve_storage_save_finished");
		e_debug(e->event(), "Failed to save script: %s",
			storage->error);

		sieve_storage_save_deinit(&sctx);
		return NULL;
	}

	sctx->mtime = (time_t)-1;

	i_assert(sctx->input != NULL);

	return sctx;
}

int sieve_storage_save_continue(struct sieve_storage_save_context *sctx)
{
	struct sieve_storage *storage = sctx->storage;
	int ret;

	i_assert(storage->v.save_continue != NULL);
	ret = storage->v.save_continue(sctx);
	if (ret < 0)
		sctx->failed = TRUE;
	return ret;
}

int sieve_storage_save_finish(struct sieve_storage_save_context *sctx)
{
	struct sieve_storage *storage = sctx->storage;
	int ret;

	i_assert(!sctx->finished);
	sctx->finished = TRUE;

	i_assert(storage->v.save_finish != NULL);
	ret = storage->v.save_finish(sctx);
	if (ret < 0) {
		struct event_passthrough *e =
			event_create_passthrough(sctx->event)->
			add_str("error", storage->error)->
			set_name("sieve_storage_save_finished");
		e_debug(e->event(), "Failed to upload script: %s",
			storage->error);

		sctx->failed = TRUE;
	}
	return ret;
}

void sieve_storage_save_set_mtime(struct sieve_storage_save_context *sctx,
				  time_t mtime)
{
	sctx->mtime = mtime;
}

struct sieve_script *
sieve_storage_save_get_tempscript(struct sieve_storage_save_context *sctx)
{
	struct sieve_storage *storage = sctx->storage;

	if (sctx->failed)
		return NULL;

	if (sctx->scriptobject != NULL)
		return sctx->scriptobject;

	i_assert(storage->v.save_get_tempscript != NULL);
	sctx->scriptobject = storage->v.save_get_tempscript(sctx);

	i_assert(sctx->scriptobject != NULL ||
		 storage->error_code != SIEVE_ERROR_NONE);
	return sctx->scriptobject;
}

bool sieve_storage_save_will_activate(struct sieve_storage_save_context *sctx)
{
	if (sctx->scriptname == NULL)
		return FALSE;

	if (sctx->active_scriptname == NULL) {
		const char *scriptname;

		if (sieve_storage_active_script_get_name(sctx->storage,
							 &scriptname) > 0) {
			sctx->active_scriptname =
				p_strdup(sctx->pool, scriptname);
		}
	}

 	/* Is the requested script active? */
	return (sctx->active_scriptname != NULL &&
		strcmp(sctx->scriptname, sctx->active_scriptname) == 0);
}

int sieve_storage_save_commit(struct sieve_storage_save_context **_sctx)
{
	struct sieve_storage_save_context *sctx = *_sctx;
	struct sieve_storage *storage;
	const char *scriptname;
	bool default_activate = FALSE;
	int ret;

	*_sctx = NULL;
	if (sctx == NULL)
		return 0;

	storage = sctx->storage;
	scriptname = sctx->scriptname;

	i_assert(!sctx->failed);
	i_assert(sctx->finished);
	i_assert(sctx->scriptname != NULL);

	/* Check whether we're replacing the default active script */
	if (storage->default_name != NULL &&
	    storage->default_location != NULL &&
	    (storage->flags & SIEVE_STORAGE_FLAG_SYNCHRONIZING) == 0 &&
	    strcmp(sctx->scriptname, storage->default_name) == 0 &&
	    sieve_storage_save_will_activate(sctx) &&
	    sieve_storage_check_script_direct(storage, storage->default_name,
					      NULL) <= 0)
		default_activate = TRUE;

	sieve_storage_save_cleanup(sctx);

	i_assert(storage->v.save_commit != NULL);
	ret = storage->v.save_commit(sctx);

	/* Implicitly activate it when we're replacing the default
	   active script */
	if (ret >= 0 && default_activate) {
		struct sieve_script *script;
		enum sieve_error error;

		script = sieve_storage_open_script(storage, scriptname, &error);
		if (script == NULL) {
			/* Somehow not actually saved */
			ret = (error == SIEVE_ERROR_NOT_FOUND ? 0 : -1);
		} else if (sieve_script_activate(script, (time_t)-1) < 0) {
			/* Failed to activate; roll back */
			ret = -1;
			(void)sieve_script_delete(script, TRUE);
		}
		if (script != NULL)
			sieve_script_unref(&script);

		if (ret < 0) {
			e_error(sctx->event,
				"Failed to implicitly activate script `%s' "
				"while replacing the default active script",
				scriptname);
		}
	}

	if (ret >= 0) {
		struct event_passthrough *e =
			event_create_passthrough(sctx->event)->
			set_name("sieve_storage_save_finished");
		e_debug(e->event(), "Finished saving script");

		/* set INBOX mailbox attribute */
		(void)sieve_storage_sync_script_save(storage, scriptname);
	} else {
		struct event_passthrough *e =
			event_create_passthrough(sctx->event)->
			add_str("error", storage->error)->
			set_name("sieve_storage_save_finished");

		e_debug(e->event(), "Failed to save script: %s",
			storage->error);
	}

	sieve_storage_save_deinit(&sctx);
	return ret;
}

void sieve_storage_save_cancel(struct sieve_storage_save_context **_sctx)
{
	struct sieve_storage_save_context *sctx = *_sctx;
	struct sieve_storage *storage;

	*_sctx = NULL;
	if (sctx == NULL)
		return;

	storage = sctx->storage;

	sctx->failed = TRUE;

	sieve_storage_save_cleanup(sctx);

	if (!sctx->finished)
		(void)sieve_storage_save_finish(sctx);

	struct event_passthrough *e =
		event_create_passthrough(sctx->event)->
		add_str("error", "Canceled")->
		set_name("sieve_storage_save_finished");
	e_debug(e->event(), "Canceled saving script");

	i_assert(storage->v.save_cancel != NULL);
	storage->v.save_cancel(sctx);

	sieve_storage_save_deinit(&sctx);
}

int sieve_storage_save_as_active(struct sieve_storage *storage,
				 struct istream *input, time_t mtime)
{
	struct event *event;
	int ret;

	event = event_create(storage->event);
	event_set_append_log_prefix(event, "active script: save: ");

	struct event_passthrough *e =
		event_create_passthrough(event)->
		set_name("sieve_storage_save_started");
	e_debug(e->event(), "Started saving active script");

	i_assert(storage->v.save_as_active != NULL);
	ret = storage->v.save_as_active(storage, input, mtime);

	if (ret >= 0) {
		struct event_passthrough *e =
			event_create_passthrough(event)->
			set_name("sieve_storage_save_finished");
		e_debug(e->event(), "Finished saving active script");
	} else {
		struct event_passthrough *e =
			event_create_passthrough(event)->
			add_str("error", storage->error)->
			set_name("sieve_storage_save_finished");
		e_debug(e->event(), "Failed to save active script: %s",
			storage->error);
	}

	event_unref(&event);
	return ret;
}

int sieve_storage_save_as(struct sieve_storage *storage, struct istream *input,
			  const char *name)
{
	struct event *event;
	int ret;

	event = sieve_storage_save_create_event(storage, name);

	struct event_passthrough *e =
		event_create_passthrough(event)->
		set_name("sieve_storage_save_started");
	e_debug(e->event(), "Started saving script");

	i_assert(storage->v.save_as != NULL);
	ret = storage->v.save_as(storage, input, name);

	if (ret >= 0) {
		struct event_passthrough *e =
			event_create_passthrough(event)->
			set_name("sieve_storage_save_finished");
		e_debug(e->event(), "Finished saving sieve script");
	} else {
		struct event_passthrough *e =
			event_create_passthrough(event)->
			add_str("error", storage->error)->
			set_name("sieve_storage_save_finished");
		e_debug(e->event(), "Failed to save script: %s",
			storage->error);
	}

	event_unref(&event);
	return ret;
}

/*
 * Checking quota
 */

bool sieve_storage_quota_validsize(struct sieve_storage *storage, size_t size,
				   uint64_t *limit_r)
{
	uint64_t max_size;

	max_size = sieve_max_script_size(storage->svinst);
	if (max_size > 0 && size > max_size) {
		*limit_r = max_size;
		return FALSE;
	}

	return TRUE;
}

uint64_t sieve_storage_quota_max_script_size(struct sieve_storage *storage)
{
	return sieve_max_script_size(storage->svinst);
}

int sieve_storage_quota_havespace(struct sieve_storage *storage,
				  const char *scriptname, size_t size,
				  enum sieve_storage_quota *quota_r,
				  uint64_t *limit_r)
{
	*quota_r = SIEVE_STORAGE_QUOTA_NONE;
	*limit_r = 0;

	/* Check the script size */
	if (!sieve_storage_quota_validsize(storage, size, limit_r)) {
		*quota_r = SIEVE_STORAGE_QUOTA_MAXSIZE;
		return 0;
	}

	/* Do we need to scan the storage (quota enabled) ? */
	if (storage->max_scripts == 0 && storage->max_storage == 0)
		return 1;

	if (storage->v.quota_havespace == NULL)
		return 1;

	return storage->v.quota_havespace(storage, scriptname, size,
					  quota_r, limit_r);
}

/*
 * Properties
 */

const char *sieve_storage_location(const struct sieve_storage *storage)
{
	return storage->location;
}

bool sieve_storage_is_default(const struct sieve_storage *storage)
{
	return storage->is_default;
}

/*
 * Error handling
 */

void sieve_storage_clear_error(struct sieve_storage *storage)
{
	i_free(storage->error);
	storage->error_code = SIEVE_ERROR_NONE;
	storage->error = NULL;
}

void sieve_storage_set_error(struct sieve_storage *storage,
			     enum sieve_error error, const char *fmt, ...)
{
	va_list va;

	sieve_storage_clear_error(storage);

	if (fmt != NULL) {
		va_start(va, fmt);
		storage->error = i_strdup_vprintf(fmt, va);
		va_end(va);
	}

	storage->error_code = error;
}

void sieve_storage_copy_error(struct sieve_storage *storage,
			      const struct sieve_storage *source)
{
	sieve_storage_clear_error(storage);
	storage->error = i_strdup(source->error);
	storage->error_code = source->error_code;
}

void sieve_storage_set_internal_error(struct sieve_storage *storage)
{
	struct tm *tm;
	char str[256];

	sieve_storage_clear_error(storage);

	/* critical errors may contain sensitive data, so let user
	   see only "Internal error" with a timestamp to make it
	   easier to look from log files the actual error message. */
	tm = localtime(&ioloop_time);

	storage->error =
		(strftime(str, sizeof(str), CRITICAL_MSG_STAMP, tm) > 0 ?
		 i_strdup(str) : i_strdup(CRITICAL_MSG));

	storage->error_code = SIEVE_ERROR_TEMP_FAILURE;
}

void sieve_storage_set_critical(struct sieve_storage *storage,
				const char *fmt, ...)
{
	va_list va;

	if (fmt != NULL) {
		if ((storage->flags & SIEVE_STORAGE_FLAG_SYNCHRONIZING) == 0) {
			va_start(va, fmt);
			e_error(storage->svinst->event, "%s storage: %s",
				storage->driver_name,
				t_strdup_vprintf(fmt, va));
			va_end(va);

			sieve_storage_set_internal_error(storage);

		} else {
			sieve_storage_clear_error(storage);

			/* no user is involved while synchronizing, so do it the
			   normal way */
			va_start(va, fmt);
			storage->error = i_strdup_vprintf(fmt, va);
			va_end(va);

			storage->error_code = SIEVE_ERROR_TEMP_FAILURE;
		}
	}
}

const char *
sieve_storage_get_last_error(struct sieve_storage *storage,
			     enum sieve_error *error_r)
{
	/* We get here only in error situations, so we have to return some
	   error. If storage->error is NULL, it means we forgot to set it at
	   some point..
	 */

	if (error_r != NULL)
		*error_r = storage->error_code;

	return storage->error != NULL ? storage->error : "Unknown error";
}