/* Copyright (c) 2006-2008 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "array.h"
#include "ioloop.h"
#include "home-expand.h"
#include "unlink-directory.h"
#include "imap-match.h"
#include "mailbox-tree.h"
#include "mailbox-list-private.h"

#include <time.h>
#include <unistd.h>
#include <dirent.h>
#include <sys/stat.h>

/* 20 * (200+1) < 4096 which is the standard PATH_MAX. Having these settings
   prevents malicious user from creating eg. "a/a/a/.../a" mailbox name and
   then start renaming them to larger names from end to beginning, which
   eventually would start causing the failures when trying to use too
   long mailbox names. */
#define MAILBOX_MAX_HIERARCHY_LEVELS 20
#define MAILBOX_MAX_HIERARCHY_NAME_LENGTH 200

/* Message to show to users when critical error occurs */
#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 mailbox_list_module_register mailbox_list_module_register = { 0 };

void (*hook_mailbox_list_created)(struct mailbox_list *list);

static ARRAY_DEFINE(mailbox_list_drivers, const struct mailbox_list *);

static bool mailbox_list_driver_find(const char *name, unsigned int *idx_r)
{
	const struct mailbox_list *const *drivers;
	unsigned int i, count;

	drivers = array_get(&mailbox_list_drivers, &count);
	for (i = 0; i < count; i++) {
		if (strcasecmp(drivers[i]->name, name) == 0) {
			*idx_r = i;
			return TRUE;
		}
	}
	return FALSE;
}

void mailbox_list_register(const struct mailbox_list *list)
{
	if (!array_is_created(&mailbox_list_drivers))
		i_array_init(&mailbox_list_drivers, 4);
	else {
		unsigned int idx;

		if (mailbox_list_driver_find(list->name, &idx)) {
			i_fatal("mailbox_list_register(%s): duplicate driver",
				list->name);
		}
	}

	array_append(&mailbox_list_drivers, &list, 1);
}

void mailbox_list_unregister(const struct mailbox_list *list)
{
	unsigned int idx;

	if (!mailbox_list_driver_find(list->name, &idx)) {
		i_fatal("mailbox_list_unregister(%s): unknown driver",
			list->name);
	}
	array_delete(&mailbox_list_drivers, idx, 1);

	if (array_count(&mailbox_list_drivers) == 0)
		array_free(&mailbox_list_drivers);
}

int mailbox_list_alloc(const char *driver, struct mailbox_list **list_r,
		       const char **error_r)
{
	const struct mailbox_list *const *class_p;
	struct mailbox_list *list;
	unsigned int idx;

	if (!mailbox_list_driver_find(driver, &idx)) {
		*error_r = t_strdup_printf("Unknown mailbox list driver: %s",
					   driver);
		return -1;
	}

	class_p = array_idx(&mailbox_list_drivers, idx);
	list = *list_r = (*class_p)->v.alloc();
	array_create(&list->module_contexts, list->pool, sizeof(void *), 5);
	return 0;
}

static const char *fix_path(const char *path)
{
	size_t len = strlen(path);

	if (len > 1 && path[len-1] == '/')
		path = t_strndup(path, len-1);
	return home_expand(path);
}

int mailbox_list_settings_parse(const char *data,
				struct mailbox_list_settings *set,
				const char **layout, const char **alt_dir_r,
				const char **error_r)
{
	const char *const *tmp, *key, *value;

	i_assert(*data != '\0');

	*error_r = NULL;
	if (alt_dir_r != NULL)
		*alt_dir_r = NULL;

	/* <root dir> */
	tmp = t_strsplit(data, ":");
	set->root_dir = fix_path(*tmp);
	tmp++;

	for (; *tmp != NULL; tmp++) {
		value = strchr(*tmp, '=');
		if (value == NULL) {
			key = *tmp;
			value = "";
		} else {
			key = t_strdup_until(*tmp, value);
			value++;
		}

		if (strcmp(key, "INBOX") == 0)
			set->inbox_path = fix_path(value);
		else if (strcmp(key, "INDEX") == 0)
			set->index_dir = fix_path(value);
		else if (strcmp(key, "CONTROL") == 0)
			set->control_dir = fix_path(value);
		else if (strcmp(key, "ALT") == 0 && alt_dir_r != NULL)
			*alt_dir_r = fix_path(value);
		else if (strcmp(key, "LAYOUT") == 0)
			*layout = value;
		else if (strcmp(key, "SUBSCRIPTIONS") == 0)
			set->subscription_fname = fix_path(value);
		else if (strcmp(key, "DIRNAME") == 0)
			set->maildir_name = value;
		else {
			*error_r = t_strdup_printf("Unknown setting: %s", key);
			return -1;
		}
	}

	if (set->index_dir != NULL && strcmp(set->index_dir, "MEMORY") == 0)
		set->index_dir = "";
	return 0;
}

void mailbox_list_init(struct mailbox_list *list, struct mail_namespace *ns,
		       const struct mailbox_list_settings *set,
		       enum mailbox_list_flags flags)
{
	i_assert(set->root_dir == NULL || *set->root_dir != '\0');
	i_assert(set->subscription_fname == NULL ||
		 *set->subscription_fname != '\0');

	list->ns = ns;
	list->flags = flags;
	list->file_create_mode = (mode_t)-1;
	list->file_create_gid = (gid_t)-1;

	/* copy settings */
	list->set.root_dir = p_strdup(list->pool, set->root_dir);
	list->set.index_dir = set->index_dir == NULL ||
		strcmp(set->index_dir, set->root_dir) == 0 ? NULL :
		p_strdup(list->pool, set->index_dir);
	list->set.control_dir = set->control_dir == NULL ||
		strcmp(set->control_dir, set->root_dir) == 0 ? NULL :
		p_strdup(list->pool, set->control_dir);

	list->set.inbox_path = p_strdup(list->pool, set->inbox_path);
	list->set.subscription_fname =
		p_strdup(list->pool, set->subscription_fname);
	list->set.maildir_name = p_strdup(list->pool, set->maildir_name);

	list->set.mail_storage_flags = set->mail_storage_flags;
	list->set.lock_method = set->lock_method;

	if ((flags & MAILBOX_LIST_FLAG_DEBUG) != 0) {
		i_info("%s: root=%s, index=%s, control=%s, inbox=%s",
		       list->name, list->set.root_dir,
		       list->set.index_dir == NULL ? "" : list->set.index_dir,
		       list->set.control_dir == NULL ?
		       "" : list->set.control_dir,
		       list->set.inbox_path == NULL ?
		       "" : list->set.inbox_path);
	}

	if (hook_mailbox_list_created != NULL)
		hook_mailbox_list_created(list);

	list->set.mail_storage_flags = NULL;
	list->set.lock_method = NULL;
}

void mailbox_list_deinit(struct mailbox_list *list)
{
	i_free_and_null(list->error_string);

	list->v.deinit(list);
}

const char *mailbox_list_get_driver_name(struct mailbox_list *list)
{
	return list->name;
}

char mailbox_list_get_hierarchy_sep(struct mailbox_list *list)
{
	return list->hierarchy_sep;
}

enum mailbox_list_flags mailbox_list_get_flags(struct mailbox_list *list)
{
	return list->flags;
}

struct mail_namespace *mailbox_list_get_namespace(struct mailbox_list *list)
{
	return list->ns;
}

void mailbox_list_get_permissions(struct mailbox_list *list,
				  mode_t *mode_r, gid_t *gid_r)
{
	const char *path;
	struct stat st;

	if (list->file_create_mode != (mode_t)-1) {
		*mode_r = list->file_create_mode;
		*gid_r = list->file_create_gid;
		return;
	}

	path = mailbox_list_get_path(list, NULL, MAILBOX_LIST_PATH_TYPE_DIR);
	if (stat(path, &st) < 0) {
		if (!ENOTFOUND(errno)) {
			mailbox_list_set_critical(list, "stat(%s) failed: %m",
						  path);
		}
		/* return safe defaults */
		*mode_r = 0600;
		*gid_r = (gid_t)-1;
		return;
	}

	list->file_create_mode = st.st_mode & 0666;
	if (S_ISDIR(st.st_mode) && (st.st_mode & S_ISGID) != 0) {
		/* directory's GID is used automatically for new files */
		list->file_create_gid = (gid_t)-1;
	} else if ((st.st_mode & 0060) == 0) {
		/* group doesn't have any permissions, so don't bother
		   changing it */
		list->file_create_gid = (gid_t)-1;
	} else if (getegid() == st.st_gid) {
		/* using our own gid, no need to change it */
		list->file_create_gid = (gid_t)-1;
	} else {
		list->file_create_gid = st.st_gid;
	}

	*mode_r = list->file_create_mode;
	*gid_r = list->file_create_gid;
}

bool mailbox_list_is_valid_pattern(struct mailbox_list *list,
				   const char *pattern)
{
	return list->v.is_valid_pattern(list, pattern);
}

bool mailbox_list_is_valid_existing_name(struct mailbox_list *list,
					 const char *name)
{
	return list->v.is_valid_existing_name(list, name);
}

bool mailbox_list_is_valid_create_name(struct mailbox_list *list,
				       const char *name)
{
	return list->v.is_valid_create_name(list, name);
}

const char *mailbox_list_get_path(struct mailbox_list *list, const char *name,
				  enum mailbox_list_path_type type)
{
	mailbox_list_clear_error(list);

	return list->v.get_path(list, name, type);
}

const char *mailbox_list_get_temp_prefix(struct mailbox_list *list)
{
	return list->v.get_temp_prefix(list, FALSE);
}

const char *mailbox_list_get_global_temp_prefix(struct mailbox_list *list)
{
	return list->v.get_temp_prefix(list, TRUE);
}

const char *mailbox_list_join_refpattern(struct mailbox_list *list,
					 const char *ref, const char *pattern)
{
	if (list->v.join_refpattern != NULL)
		return list->v.join_refpattern(list, ref, pattern);

	/* the default implementation: */
	if (*ref != '\0') {
		/* merge reference and pattern */
		pattern = t_strconcat(ref, pattern, NULL);
	}
	return pattern;
}

int mailbox_list_get_mailbox_name_status(struct mailbox_list *list,
					 const char *name,
					 enum mailbox_name_status *status)
{
	mailbox_list_clear_error(list);

	if (!mailbox_list_is_valid_existing_name(list, name)) {
		*status = MAILBOX_NAME_INVALID;
		return 0;
	}

	return list->v.get_mailbox_name_status(list, name, status);
}

struct mailbox_list_iterate_context *
mailbox_list_iter_init(struct mailbox_list *list, const char *pattern,
		       enum mailbox_list_iter_flags flags)
{
	const char *patterns[2];

	patterns[0] = pattern;
	patterns[1] = NULL;
	return mailbox_list_iter_init_multiple(list, patterns, flags);
}

struct mailbox_list_iterate_context *
mailbox_list_iter_init_multiple(struct mailbox_list *list,
				const char *const *patterns,
				enum mailbox_list_iter_flags flags)
{
	i_assert(*patterns != NULL);

	mailbox_list_clear_error(list);
	return list->v.iter_init(list, patterns, flags);
}

const struct mailbox_info *
mailbox_list_iter_next(struct mailbox_list_iterate_context *ctx)
{
	return ctx->list->v.iter_next(ctx);
}

int mailbox_list_iter_deinit(struct mailbox_list_iterate_context **_ctx)
{
	struct mailbox_list_iterate_context *ctx = *_ctx;

	*_ctx = NULL;

	return ctx->list->v.iter_deinit(ctx);
}

int mailbox_list_set_subscribed(struct mailbox_list *list,
				const char *name, bool set)
{
	mailbox_list_clear_error(list);

	return list->v.set_subscribed(list, name, set);
}

int mailbox_list_delete_mailbox(struct mailbox_list *list, const char *name)
{
	if (!mailbox_list_is_valid_existing_name(list, name)) {
		mailbox_list_set_error(list, MAIL_ERROR_PARAMS,
				       "Invalid mailbox name");
		return -1;
	}
	if (strcmp(name, "INBOX") == 0) {
		mailbox_list_set_error(list, MAIL_ERROR_NOTPOSSIBLE,
				       "INBOX can't be deleted.");
		return -1;
	}
	return list->v.delete_mailbox(list, name);
}

int mailbox_list_rename_mailbox(struct mailbox_list *list,
				const char *oldname, const char *newname)
{
	if (!mailbox_list_is_valid_existing_name(list, oldname) ||
	    !mailbox_list_is_valid_create_name(list, newname)) {
		mailbox_list_set_error(list, MAIL_ERROR_PARAMS,
				       "Invalid mailbox name");
		return -1;
	}

	return list->v.rename_mailbox(list, oldname, newname);
}

static int mailbox_list_try_delete(struct mailbox_list *list, const char *dir)
{
	if (unlink_directory(dir, TRUE) == 0 || errno == ENOENT)
		return 0;

	if (errno == ENOTEMPTY) {
		/* We're most likely using NFS and we can't delete
		   .nfs* files. */
		mailbox_list_set_error(list, MAIL_ERROR_NOTPOSSIBLE,
			"Mailbox is still open in another session, "
			"can't delete it.");
	} else {
		mailbox_list_set_critical(list,
			"unlink_directory(%s) failed: %m", dir);
	}
	return -1;
}

int mailbox_list_delete_index_control(struct mailbox_list *list,
				      const char *name)
{
	const char *path, *index_dir, *dir;

	path = mailbox_list_get_path(list, name,
				     MAILBOX_LIST_PATH_TYPE_MAILBOX);

	/* delete the index directory first, so that if we crash we don't
	   leave indexes for deleted mailboxes lying around */
	index_dir = mailbox_list_get_path(list, name,
					  MAILBOX_LIST_PATH_TYPE_INDEX);
	if (*index_dir != '\0' && strcmp(index_dir, path) != 0) {
		if (mailbox_list_try_delete(list, index_dir) < 0)
			return -1;
	}

	/* control directory next */
	dir = mailbox_list_get_path(list, name, MAILBOX_LIST_PATH_TYPE_CONTROL);
	if (*dir != '\0' && strcmp(dir, path) != 0 &&
	    strcmp(dir, index_dir) != 0) {
		if (mailbox_list_try_delete(list, index_dir) < 0)
			return -1;
	}
	return 0;
}

static void node_fix_parents(struct mailbox_node *node)
{
	/* If we happened to create any of the parents, we need to mark them
	   nonexistent. */
	node = node->parent;
	for (; node != NULL; node = node->parent) {
		if ((node->flags & MAILBOX_MATCHED) == 0)
			node->flags |= MAILBOX_NONEXISTENT;
	}
}

static void
mailbox_list_iter_update_real(struct mailbox_list_iterate_context *ctx,
			      struct mailbox_tree_context *tree_ctx,
			      struct imap_match_glob *glob, bool update_only,
			      bool match_parents, const char *name)
{
	struct mail_namespace *ns = ctx->list->ns;
	struct mailbox_node *node;
	enum mailbox_info_flags create_flags, always_flags;
	enum imap_match_result match;
	const char *p;
	bool created, add_matched;

	create_flags = (update_only ||
			(ctx->flags & MAILBOX_LIST_ITER_RETURN_NO_FLAGS) == 0) ?
		(MAILBOX_NONEXISTENT | MAILBOX_NOCHILDREN) : 0;
	always_flags = MAILBOX_SUBSCRIBED;
	add_matched = TRUE;

	for (;;) {
		created = FALSE;
		match = imap_match(glob, name);
		if (match == IMAP_MATCH_YES) {
			node = update_only ?
				mailbox_tree_lookup(tree_ctx, name) :
				mailbox_tree_get(tree_ctx, name, &created);
			if (created) {
				node->flags = create_flags;
				if (create_flags != 0)
					node_fix_parents(node);
			}
			if (node != NULL) {
				if (!update_only && add_matched)
					node->flags |= MAILBOX_MATCHED;
				node->flags |= always_flags;
			}
			/* We don't want to show the parent mailboxes unless
			   something else matches them, but if they are matched
			   we want to show them having child subscriptions */
			add_matched = FALSE;
		} else {
			if ((match & IMAP_MATCH_PARENT) == 0)
				break;
			/* We've a (possibly) non-subscribed parent mailbox
			   which has a subscribed child mailbox. Make sure we
			   return the parent mailbox. */
		}

		if (!match_parents)
			break;

		/* see if parent matches */
		p = strrchr(name, ns->sep);
		if (p == NULL)
			break;

		name = t_strdup_until(name, p);
		create_flags &= ~MAILBOX_NOCHILDREN;
		always_flags = MAILBOX_CHILDREN | MAILBOX_CHILD_SUBSCRIBED;
	}
}

void mailbox_list_iter_update(struct mailbox_list_iterate_context *ctx,
			      struct mailbox_tree_context *tree_ctx,
			      struct imap_match_glob *glob, bool update_only,
			      bool match_parents, const char *name)
{
	T_FRAME(
		mailbox_list_iter_update_real(ctx, tree_ctx, glob, update_only,
					      match_parents, name);
	);
}

bool mailbox_list_name_is_too_large(const char *name, char sep)
{
	unsigned int levels = 1, level_len = 0;

	for (; *name != '\0'; name++) {
		if (*name == sep) {
			if (level_len > MAILBOX_MAX_HIERARCHY_NAME_LENGTH)
				return TRUE;
			levels++;
			level_len = 0;
		} else {
			level_len++;
		}
	}

	if (level_len > MAILBOX_MAX_HIERARCHY_NAME_LENGTH)
		return TRUE;
	if (levels > MAILBOX_MAX_HIERARCHY_LEVELS)
		return TRUE;
	return FALSE;
}

enum mailbox_list_file_type
mailbox_list_get_file_type(const struct dirent *d ATTR_UNUSED)
{
	enum mailbox_list_file_type type;

#ifdef HAVE_DIRENT_D_TYPE
	switch (d->d_type) {
	case DT_UNKNOWN:
		type = MAILBOX_LIST_FILE_TYPE_UNKNOWN;
		break;
	case DT_REG:
		type = MAILBOX_LIST_FILE_TYPE_FILE;
		break;
	case DT_DIR:
		type = MAILBOX_LIST_FILE_TYPE_DIR;
		break;
	case DT_LNK:
		type = MAILBOX_LIST_FILE_TYPE_SYMLINK;
		break;
	default:
		type = MAILBOX_LIST_FILE_TYPE_OTHER;
		break;
	}
#else
	type = MAILBOX_LIST_FILE_TYPE_UNKNOWN;
#endif
	return type;
}

const char *mailbox_list_get_last_error(struct mailbox_list *list,
					enum mail_error *error_r)
{
	*error_r = list->error;

	return list->error_string != NULL ? list->error_string :
		"Unknown internal list error";
}

void mailbox_list_clear_error(struct mailbox_list *list)
{
	i_free_and_null(list->error_string);

	list->error = MAIL_ERROR_NONE;
}

void mailbox_list_set_error(struct mailbox_list *list,
			    enum mail_error error, const char *string)
{
	i_free(list->error_string);
	list->error_string = i_strdup(string);

	list->error = error;
}

void mailbox_list_set_internal_error(struct mailbox_list *list)
{
	struct tm *tm;
	char str[256];

	tm = localtime(&ioloop_time);

	i_free(list->error_string);
	list->error_string =
		strftime(str, sizeof(str), CRITICAL_MSG_STAMP, tm) > 0 ?
		i_strdup(str) : i_strdup(CRITICAL_MSG);
	list->error = MAIL_ERROR_TEMP;
}

void mailbox_list_set_critical(struct mailbox_list *list, const char *fmt, ...)
{
	va_list va;

	va_start(va, fmt);
	i_error("%s", t_strdup_vprintf(fmt, va));
	va_end(va);

	/* 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. */
	mailbox_list_set_internal_error(list);
}

bool mailbox_list_set_error_from_errno(struct mailbox_list *list)
{
	const char *error_string;
	enum mail_error error;

	if (!mail_error_from_errno(&error, &error_string))
		return FALSE;

	mailbox_list_set_error(list, error, error_string);
	return TRUE;
}