/*
 * Copyright (C) Joerg Lenneis 2003
 * Copyright (c) Frank Lahm 2009
 * All Rights Reserved.  See COPYING.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif /* HAVE_CONFIG_H */

#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/file.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>

#include <bstrlib.h>

#include <atalk/cnid_bdb_private.h>
#include <atalk/errchk.h>
#include <atalk/logger.h>
#include <atalk/netatalk_conf.h>
#include <atalk/util.h>

#include "db_param.h"
#include "dbd.h"
#include "dbif.h"
#include "pack.h"
#include "comm.h"

/*
   Note: DB_INIT_LOCK is here so we can run the db_* utilities while netatalk is running.
   It's a likey performance hit, but it might we worth it.
 */
#define DBOPTIONS (DB_CREATE | DB_INIT_LOG | DB_INIT_MPOOL | DB_INIT_LOCK | DB_INIT_TXN)

static DBD *dbd;
static int exit_sig = 0;
static int db_locked;
static bstring dbpath;
static struct db_param *dbp;
static struct vol *vol;

static void sig_exit(int signo)
{
    exit_sig = signo;
    return;
}

static void block_sigs_onoff(int block)
{
    sigset_t set;
    sigemptyset(&set);
    sigaddset(&set, SIGINT);
    sigaddset(&set, SIGTERM);

    if (block) {
        sigprocmask(SIG_BLOCK, &set, NULL);
    } else {
        sigprocmask(SIG_UNBLOCK, &set, NULL);
    }

    return;
}

/*!
 * @file
 * @brief CNID DBD (Database Daemon) Backend startup routines
 *
 * The dbd_XXX and comm_XXX functions all obey the same protocol for return values:
 *
 * - 1: Success, if transactions are used commit.
 * - 0: Failure, but we continue to serve requests. If transactions are used abort/rollback.
 * - -1: Fatal error, either from the database or from the socket.
 *   Abort the transaction if applicable (which might fail as well) and then exit.
 *
 * We always try to notify the client process about the outcome, the result field
 * of the cnid_dbd_rply structure contains further details.
*/

/*!
 * @brief Get lock on db lock file
 *
 * @param[in] cmd     lock command:
 *                     - LOCK_FREE:   close lockfd
 *                     - LOCK_UNLOCK: unlock lockm keep lockfd open
 *                     - LOCK_EXCL:   F_WRLCK on lockfd
 *                     - LOCK_SHRD:   F_RDLCK on lockfd
 * @param[in] dbpath  path to lockfile, only used on first call,
 *                     later the stored fd is used
 * @returns           depending on lock command:
 *                     - LOCK_FREE/LOCK_UNLOCK return 0 on success, -1 on error
 *                     - LOCK_EXCL/LOCK_SHRD return LOCK_EXCL or LOCK_SHRD respectively on
 *                       success, 0 if the lock couldn't be acquired, -1 on other errors
 */
static int get_lock(int cmd, const char *dbpath)
{
    static int lockfd = -1;
    int ret;
    char lockpath[PATH_MAX];
    struct stat st;
    LOG(log_debug, logtype_cnid, "get_lock(%s, \"%s\")",
        cmd == LOCK_EXCL ? "LOCK_EXCL" :
        cmd == LOCK_SHRD ? "LOCK_SHRD" :
        cmd == LOCK_FREE ? "LOCK_FREE" :
        cmd == LOCK_UNLOCK ? "LOCK_UNLOCK" : "UNKNOWN",
        dbpath ? dbpath : "");

    switch (cmd) {
    case LOCK_FREE:
        if (lockfd == -1) {
            return -1;
        }

        close(lockfd);
        lockfd = -1;
        return 0;

    case LOCK_UNLOCK:
        if (lockfd == -1) {
            return -1;
        }

        return unlock(lockfd, 0, SEEK_SET, 0);

    case LOCK_EXCL:
    case LOCK_SHRD:
        if (lockfd == -1) {
            if (dbpath == NULL) {
                LOG(log_error, logtype_cnid, "get_lock: dbpath is NULL");
                return -1;
            }

            if ((strlen(dbpath) + strlen(&LOCKFILENAME[1])) > (PATH_MAX - 1)) {
                LOG(log_error, logtype_cnid, ".AppleDB pathname too long");
                return -1;
            }

            strncpy(lockpath, dbpath, PATH_MAX - 1);
            strcat(lockpath, "/");
            strcat(lockpath, LOCKFILENAME);

            if ((lockfd = open(lockpath, O_RDWR | O_CREAT, 0644)) < 0) {
                LOG(log_error, logtype_cnid, "Error opening lockfile: %s", strerror(errno));
                return -1;
            }

            if ((stat(dbpath, &st)) != 0) {
                LOG(log_error, logtype_cnid, "Error statting lockfile: %s", strerror(errno));
                return -1;
            }

            if ((chown(lockpath, st.st_uid, st.st_gid)) != 0) {
                LOG(log_error, logtype_cnid, "Error inheriting lockfile permissions: %s",
                    strerror(errno));
                return -1;
            }
        }

        if (cmd == LOCK_EXCL) {
            ret = write_lock(lockfd, 0, SEEK_SET, 0);
        } else {
            ret = read_lock(lockfd, 0, SEEK_SET, 0);
        }

        if (ret != 0) {
            if (cmd == LOCK_SHRD) {
                LOG(log_error, logtype_cnid, "Volume CNID db is locked, try again...");
            }

            return 0;
        }

        LOG(log_debug, logtype_cnid, "get_lock: got %s lock",
            cmd == LOCK_EXCL ? "LOCK_EXCL" : "LOCK_SHRD");
        return cmd;

    default:
        return -1;
    } /* switch(cmd) */
}

static int open_db(void)
{
    EC_INIT;

    /* Get db lock */
    if ((db_locked = get_lock(LOCK_EXCL, bdata(dbpath))) != LOCK_EXCL) {
        LOG(log_error, logtype_cnid, "main: fatal db lock error");
        EC_FAIL;
    }

    if (NULL == (dbd = dbif_init(bdata(dbpath), "cnid2.db"))) {
        EC_FAIL;
    }

    /* Only recover if we got the lock */
    if (dbif_env_open(dbd, dbp, DBOPTIONS | DB_RECOVER) < 0) {
        EC_FAIL;
    }

    LOG(log_debug, logtype_cnid, "Finished initializing BerkeleyDB environment");

    if (dbif_open(dbd, dbp, 0) < 0) {
        EC_FAIL;
    }

    LOG(log_debug, logtype_cnid, "Finished opening BerkeleyDB databases");
EC_CLEANUP:

    if (ret != 0) {
        if (dbd) {
            (void)dbif_close(dbd);
            dbd = NULL;
        }
    }

    EC_EXIT;
}

static int delete_db(void)
{
    EC_INIT;
    int cwd = -1;
    EC_ZERO(get_lock(LOCK_FREE, bdata(dbpath)));
    EC_NEG1(cwd = open(".", O_RDONLY));

    if (chdir(cfrombstr(dbpath)) < 0) {
        LOG(log_error, logtype_cnid, "delete_db: could not chdir to \"%s\": %s",
            bdata(dbpath), strerror(errno));
        EC_FAIL;
    }

    if (system("rm -f cnid2.db lock log.* __db.*") < 0) {
        LOG(log_error, logtype_cnid, "delete_db: could not rm things");
    }

    if ((db_locked = get_lock(LOCK_EXCL, bdata(dbpath))) != LOCK_EXCL) {
        LOG(log_error, logtype_cnid, "main: fatal db lock error");
        EC_FAIL;
    }

    LOG(log_warning, logtype_cnid,
        "Recreated CNID BerkeleyDB databases of volume \"%s\"", vol->v_localname);
EC_CLEANUP:

    if (cwd != -1) {
        if (fchdir(cwd) < 0) {
            LOG(log_error, logtype_default, "Can't fchdir(%d): %s", cwd, strerror(errno));
        }

        close(cwd);
    }

    EC_EXIT;
}


/*!
 * @brief Close dbd if open, delete it, reopen
 *
 * Also tries to copy the rootinfo key, that would allow for keeping the db stamp
 * and last used CNID
 */
static int reinit_db(void)
{
    EC_INIT;
    DBT key, data;
    bool copyRootInfo = false;

    if (dbd) {
        memset(&key, 0, sizeof(key));
        memset(&data, 0, sizeof(data));
        key.data = ROOTINFO_KEY;
        key.size = ROOTINFO_KEYLEN;

        if (dbif_get(dbd, DBIF_CNID, &key, &data, 0) <= 0) {
            LOG(log_error, logtype_cnid,
                "dbif_copy_rootinfokey: Error getting rootinfo record");
            copyRootInfo = false;
        } else {
            copyRootInfo = true;
        }

        (void)dbif_close(dbd);
    }

    EC_ZERO_LOG(delete_db());
    EC_ZERO_LOG(open_db());

    if (copyRootInfo == true) {
        memset(&key, 0, sizeof(key));
        key.data = ROOTINFO_KEY;
        key.size = ROOTINFO_KEYLEN;

        if (dbif_put(dbd, DBIF_CNID, &key, &data, 0) != 0) {
            LOG(log_error, logtype_cnid,
                "dbif_copy_rootinfokey: Error writing rootinfo key");
            EC_FAIL;
        }
    }

EC_CLEANUP:
    EC_EXIT;
}

static int loop(struct db_param *dbp)
{
    struct cnid_dbd_rqst rqst;
    struct cnid_dbd_rply rply;
    time_t timeout;
    int ret, cret;
    int count;
    time_t now, time_next_flush, time_last_rqst;
    char timebuf[64];
    static char namebuf[MAXPATHLEN + 1];
    sigset_t set;
    sigemptyset(&set);
    sigprocmask(SIG_SETMASK, NULL, &set);
    sigdelset(&set, SIGINT);
    sigdelset(&set, SIGTERM);
    count = 0;
    now = time(NULL);
    time_next_flush = now + dbp->flush_interval;
    time_last_rqst = now;
    rqst.name = namebuf;
    strftime(timebuf, 63, "%b %d %H:%M:%S.", localtime(&time_next_flush));
    LOG(log_debug, logtype_cnid,
        "Checkpoint interval: %d seconds. Next checkpoint: %s",
        dbp->flush_interval, timebuf);

    while (1) {
        timeout = MIN(time_next_flush, time_last_rqst + dbp->idle_timeout);

        if (timeout > now) {
            timeout -= now;
        } else {
            timeout = 1;
        }

        if ((cret = comm_rcv(&rqst, timeout, &set, &now)) < 0) {
            return -1;
        }

        if (cret == 0) {
            /* comm_rcv returned from select without receiving anything. */
            if (exit_sig) {
                /* Received signal (TERM|INT) */
                return 0;
            }

            if (now - time_last_rqst >= dbp->idle_timeout && comm_nbe() <= 0) {
                /* Idle timeout */
                return 0;
            }

            /* still active connections, reset time_last_rqst */
            time_last_rqst = now;
        } else {
            /* We got a request */
            time_last_rqst = now;
            memset(&rply, 0, sizeof(rply));

            switch (rqst.op) {
            /* ret gets set here */
            case CNID_DBD_OP_OPEN:
            case CNID_DBD_OP_CLOSE:
                /* open/close are noops for now. */
                rply.namelen = 0;
                ret = 1;
                break;

            case CNID_DBD_OP_ADD:
                ret = dbd_add(dbd, &rqst, &rply);
                break;

            case CNID_DBD_OP_GET:
                ret = dbd_get(dbd, &rqst, &rply);
                break;

            case CNID_DBD_OP_RESOLVE:
                ret = dbd_resolve(dbd, &rqst, &rply);
                break;

            case CNID_DBD_OP_LOOKUP:
                ret = dbd_lookup(dbd, &rqst, &rply);
                break;

            case CNID_DBD_OP_UPDATE:
                ret = dbd_update(dbd, &rqst, &rply);
                break;

            case CNID_DBD_OP_DELETE:
                ret = dbd_delete(dbd, &rqst, &rply, DBIF_CNID);
                break;

            case CNID_DBD_OP_GETSTAMP:
                ret = dbd_getstamp(dbd, &rqst, &rply);
                break;

            case CNID_DBD_OP_REBUILD_ADD:
                ret = dbd_rebuild_add(dbd, &rqst, &rply);
                break;

            case CNID_DBD_OP_SEARCH:
                ret = dbd_search(dbd, &rqst, &rply);
                break;

            case CNID_DBD_OP_WIPE:
                ret = reinit_db();
                break;

            default:
                LOG(log_error, logtype_cnid, "loop: unknown op %d", rqst.op);
                ret = -1;
                break;
            }

            if ((cret = comm_snd(&rply)) < 0 || ret < 0) {
                dbif_txn_abort(dbd);
                return -1;
            }

            if (ret == 0 || cret == 0) {
                if (dbif_txn_abort(dbd) < 0) {
                    return -1;
                }
            } else {
                ret = dbif_txn_commit(dbd);

                if (ret < 0) {
                    return -1;
                } else if (ret > 0)
                    /* We had a designated txn because we wrote to the db */
                {
                    count++;
                }
            }
        } /* got a request */

        /*
          Shall we checkpoint bdb ?
          "flush_interval" seconds passed ?
        */
        if (now >= time_next_flush) {
            LOG(log_info, logtype_cnid, "Checkpointing BerkeleyDB for volume '%s'",
                dbp->dir);

            if (dbif_txn_checkpoint(dbd, 0, 0, 0) < 0) {
                return -1;
            }

            count = 0;
            time_next_flush = now + dbp->flush_interval;
            strftime(timebuf, 63, "%b %d %H:%M:%S.", localtime(&time_next_flush));
            LOG(log_debug, logtype_cnid,
                "Checkpoint interval: %d seconds. Next checkpoint: %s",
                dbp->flush_interval, timebuf);
        }

        /*
           Shall we checkpoint bdb ?
           Have we commited "count" more changes than "flush_frequency" ?
        */
        if (count > dbp->flush_frequency) {
            LOG(log_info, logtype_cnid,
                "Checkpointing BerkeleyDB after %d writes for volume '%s'", count, dbp->dir);

            if (dbif_txn_checkpoint(dbd, 0, 0, 0) < 0) {
                return -1;
            }

            count = 0;
        }
    } /* while(1) */
}

/* ------------------------ */
static void switch_to_user(char *dir)
{
    struct stat st;

    if (dir == NULL) {
        LOG(log_error, logtype_cnid, "switch_to_user: dir is NULL");
        exit(1);
    }

    if (chdir(dir) < 0) {
        LOG(log_error, logtype_cnid, "chdir to %s failed: %s", dir, strerror(errno));
        exit(1);
    }

    if (stat(".", &st) < 0) {
        LOG(log_error, logtype_cnid, "error in stat for %s: %s", dir, strerror(errno));
        exit(1);
    }

    if (setgroups(0, NULL) < 0) {
        LOG(log_error, logtype_cnid, "error in setgroups: %s", strerror(errno));
        exit(1);
    }

    if (!getuid()) {
        LOG(log_debug, logtype_cnid, "Setting uid/gid to %i/%i", st.st_uid, st.st_gid);

        if (setgid(st.st_gid) < 0 || setuid(st.st_uid) < 0) {
            LOG(log_error, logtype_cnid, "uid/gid: %s", strerror(errno));
            exit(1);
        }
    }
}


/* ----------------------- */
static void set_signal(void)
{
    struct sigaction sv;
    sv.sa_handler = sig_exit;
    sv.sa_flags = 0;
    sigemptyset(&sv.sa_mask);
    sigaddset(&sv.sa_mask, SIGINT);
    sigaddset(&sv.sa_mask, SIGTERM);

    if (sigaction(SIGINT, &sv, NULL) < 0 || sigaction(SIGTERM, &sv, NULL) < 0) {
        LOG(log_error, logtype_cnid, "main: sigaction: %s", strerror(errno));
        exit(1);
    }

    sv.sa_handler = SIG_IGN;
    sigemptyset(&sv.sa_mask);

    if (sigaction(SIGPIPE, &sv, NULL) < 0) {
        LOG(log_error, logtype_cnid, "main: sigaction: %s", strerror(errno));
        exit(1);
    }
}

static uid_t uid_from_name(const char *name)
{
    struct passwd *pwd;
    pwd = getpwnam(name);

    if (pwd == NULL) {
        return 0;
    }

    return pwd->pw_uid;
}

/* ------------------------ */
int main(int argc, char *argv[])
{
    EC_INIT;
    int ctrlfd = -1, clntfd = -1;
    AFPObj obj = { 0 };
    char *volpath = NULL;
    char *username = NULL;

    while ((ret = getopt(argc, argv, ":F:l:p:t:u:vV")) != -1) {
        switch (ret) {
        case 'F':
            if (obj.cmdlineconfigfile) {
                free((void *)obj.cmdlineconfigfile);
            }

            obj.cmdlineconfigfile = strdup(optarg);
            break;

        case 'p':
            if (volpath) {
                free((void *)volpath);
            }

            volpath = strdup(optarg);
            break;

        case 'l':
            clntfd = atoi(optarg);
            break;

        case 't':
            ctrlfd = atoi(optarg);
            break;

        case 'u':
            if (username) {
                free((void *)username);
            }

            username = strdup(optarg);
            break;

        case 'v':
        case 'V':
            if (obj.cmdlineconfigfile) {
                free((void *)obj.cmdlineconfigfile);
            }

            if (volpath) {
                free((void *)volpath);
            }

            if (username) {
                free((void *)username);
            }

            printf("cnid_dbd (Netatalk %s)\n", VERSION);
            return -1;

        case ':':
            break;
        }
    }

    if (ctrlfd == -1 || clntfd == -1 || !volpath) {
        LOG(log_error, logtype_cnid, "main: bad IPC fds");

        if (obj.cmdlineconfigfile) {
            free((void *)obj.cmdlineconfigfile);
        }

        if (volpath) {
            free((void *)volpath);
        }

        if (username) {
            free((void *)username);
        }

        exit(EXIT_FAILURE);
    }

    EC_ZERO(afp_config_parse(&obj, "cnid_dbd"));

    if (username) {
        strlcpy(obj.username, username, MAXUSERLEN);
        obj.uid = uid_from_name(username);

        if (!obj.uid) {
            EC_FAIL_LOG("unknown user: '%s'", username);
        }
    }

    LOG(log_debug, logtype_cnid, "user: %s, path %s",
        username ? username : "-", volpath);
    EC_ZERO(load_volumes(&obj, LV_ALL));
    EC_NULL(vol = getvolbypath(&obj, volpath));
    EC_ZERO(load_charset(vol));
    pack_setvol(vol);
    EC_NULL(dbpath = bfromcstr(vol->v_dbpath));
    EC_ZERO(bcatcstr(dbpath, "/.AppleDB"));
    LOG(log_debug, logtype_cnid, "db dir: \"%s\"", bdata(dbpath));
    switch_to_user(bdata(dbpath));
    set_signal();
    /* SIGINT and SIGTERM are always off, unless we are in pselect */
    block_sigs_onoff(1);

    if ((dbp = db_param_read(bdata(dbpath))) == NULL) {
        EC_FAIL;
    }

    LOG(log_maxdebug, logtype_cnid, "Finished parsing db_param config file");

    if (open_db() != 0) {
        LOG(log_error, logtype_cnid, "Failed to open CNID database for volume \"%s\"",
            vol->v_localname);
        EC_ZERO_LOG(reinit_db());
    }

    if (comm_init(dbp, ctrlfd, clntfd) < 0) {
        ret = -1;
        goto close_db;
    }

    if (loop(dbp) < 0) {
        ret = -1;
        goto close_db;
    }

close_db:

    if (dbif_close(dbd) < 0) {
        ret = -1;
    }

    if (dbif_env_remove(bdata(dbpath)) < 0) {
        ret = -1;
    }

EC_CLEANUP:

    if (obj.cmdlineconfigfile) {
        free((void *)obj.cmdlineconfigfile);
    }

    if (volpath) {
        free((void *)volpath);
    }

    if (username) {
        free((void *)username);
    }

    if (ret != 0) {
        exit(1);
    }

    if (exit_sig) {
        LOG(log_info, logtype_cnid, "main: Exiting on signal %i", exit_sig);
    } else {
        LOG(log_info, logtype_cnid, "main: Idle timeout, exiting");
    }

    EC_EXIT;
}
