src/director/user-directory.c

	user-directory.c revision 2726de0d31ed0f1a1425e4c8d167f7681e07fc25
/* Copyright (c) 2010 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "ioloop.h"
#include "array.h"
#include "md5.h"
#include "hash.h"
#include "llist.h"
#include "mail-host.h"
#include "user-directory.h"

#define MAX_CLOCK_DRIFT_SECS 2

struct user_directory_iter {
    struct user_directory *dir;
    struct user *pos;
};

struct user_directory {
    /* const char *username => struct user* */
    struct hash_table *hash;
    /* sorted by time */
    struct user *head, *tail;

    ARRAY_DEFINE(iters, struct user_directory_iter *);

    unsigned int timeout_secs;
};

static void user_move_iters(struct user_directory *dir, struct user *user)
{
    struct user_directory_iter *const *iterp;

    array_foreach(&dir->iters, iterp) {
        if ((*iterp)->pos == user)
            (*iterp)->pos = user->next;
    }
}

static void user_free(struct user_directory *dir, struct user *user)
{
    i_assert(user->host->user_count > 0);
    user->host->user_count--;

    user_move_iters(dir, user);

    hash_table_remove(dir->hash, POINTER_CAST(user->username_hash));
    DLLIST2_REMOVE(&dir->head, &dir->tail, user);
    i_free(user);
}

static void user_directory_drop_expired(struct user_directory *dir)
{
    while (dir->head != NULL &&
           !user_directory_user_has_connections(dir, dir->head))
        user_free(dir, dir->head);
}

struct user *user_directory_lookup(struct user_directory *dir,
                   unsigned int username_hash)
{
    user_directory_drop_expired(dir);

    return hash_table_lookup(dir->hash, POINTER_CAST(username_hash));
}

struct user *
user_directory_add(struct user_directory *dir, unsigned int username_hash,
           struct mail_host *host, time_t timestamp)
{
    struct user *user;

    user = i_new(struct user, 1);
    user->username_hash = username_hash;
    user->host = host;
    user->host->user_count++;
    user->timestamp = timestamp;
    DLLIST2_APPEND(&dir->head, &dir->tail, user);

    hash_table_insert(dir->hash, POINTER_CAST(user->username_hash), user);
    return user;
}

void user_directory_refresh(struct user_directory *dir, struct user *user)
{
    user_move_iters(dir, user);

    user->timestamp = ioloop_time;
    DLLIST2_REMOVE(&dir->head, &dir->tail, user);
    DLLIST2_APPEND(&dir->head, &dir->tail, user);
}

void user_directory_remove_host(struct user_directory *dir,
                struct mail_host *host)
{
    struct user *user, *next;

    for (user = dir->head; user != NULL; user = next) {
        next = user->next;

        if (user->host == host)
            user_free(dir, user);
    }
}

unsigned int user_directory_get_username_hash(const char *username)
{
    unsigned char md5[MD5_RESULTLEN];
    unsigned int i, hash = 0;

    md5_get_digest(username, strlen(username), md5);
    for (i = 0; i < sizeof(hash); i++)
        hash = (hash << CHAR_BIT) | md5[i];
    return hash;
}

bool user_directory_user_has_connections(struct user_directory *dir,
                     struct user *user)
{
    time_t expire_timestamp = user->timestamp + dir->timeout_secs;

    return expire_timestamp - MAX_CLOCK_DRIFT_SECS >= ioloop_time;
}

struct user_directory *user_directory_init(unsigned int timeout_secs)
{
    struct user_directory *dir;

    dir = i_new(struct user_directory, 1);
    dir->timeout_secs = timeout_secs;
    dir->hash = hash_table_create(default_pool, default_pool,
                      0, NULL, NULL);
    i_array_init(&dir->iters, 8);
    return dir;
}

void user_directory_deinit(struct user_directory **_dir)
{
    struct user_directory *dir = *_dir;

    *_dir = NULL;

    i_assert(array_count(&dir->iters) == 0);

    while (dir->head != NULL)
        user_free(dir, dir->head);
    hash_table_destroy(&dir->hash);
    array_free(&dir->iters);
    i_free(dir);
}

struct user_directory_iter *
user_directory_iter_init(struct user_directory *dir)
{
    struct user_directory_iter *iter;

    iter = i_new(struct user_directory_iter, 1);
    iter->dir = dir;
    iter->pos = dir->head;
    array_append(&dir->iters, &iter, 1);
    return iter;
}

struct user *user_directory_iter_next(struct user_directory_iter *iter)
{
    struct user *user;

    user = iter->pos;
    if (user == NULL)
        return FALSE;

    iter->pos = user->next;
    return user;
}

void user_directory_iter_deinit(struct user_directory_iter **_iter)
{
    struct user_directory_iter *iter = *_iter;
    struct user_directory_iter *const *iters;
    unsigned int i, count;

    *_iter = NULL;

    iters = array_get(&iter->dir->iters, &count);
    for (i = 0; i < count; i++) {
        if (iters[i] == iter) {
            array_delete(&iter->dir->iters, i, 1);
            break;
        }
    }
    i_free(iter);
}