config.c

/* Configuration file parsing and CONFIG GET/SET commands implementation.
 *
 * Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *   * Neither the name of Redis nor the names of its contributors may be used
 *     to endorse or promote products derived from this software without
 *     specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "redis.h"

#include <fcntl.h>
#include <sys/stat.h>

static struct {
    const char     *name;
    const int       value;
} validSyslogFacilities[] = {
    {"user",    LOG_USER},
    {"local0",  LOG_LOCAL0},
    {"local1",  LOG_LOCAL1},
    {"local2",  LOG_LOCAL2},
    {"local3",  LOG_LOCAL3},
    {"local4",  LOG_LOCAL4},
    {"local5",  LOG_LOCAL5},
    {"local6",  LOG_LOCAL6},
    {"local7",  LOG_LOCAL7},
    {NULL, 0}
};

clientBufferLimitsConfig clientBufferLimitsDefaults[REDIS_CLIENT_LIMIT_NUM_CLASSES] = {
    {0, 0, 0}, /* normal */
    {1024*1024*256, 1024*1024*64, 60}, /* slave */
    {1024*1024*32, 1024*1024*8, 60}  /* pubsub */
};

/*-----------------------------------------------------------------------------
 * Config file parsing
 *----------------------------------------------------------------------------*/

int yesnotoi(char *s) {
    if (!strcasecmp(s,"yes")) return 1;
    else if (!strcasecmp(s,"no")) return 0;
    else return -1;
}

void appendServerSaveParams(time_t seconds, int changes) {
    server.saveparams = zrealloc(server.saveparams,sizeof(struct saveparam)*(server.saveparamslen+1));
    server.saveparams[server.saveparamslen].seconds = seconds;
    server.saveparams[server.saveparamslen].changes = changes;
    server.saveparamslen++;
}

void resetServerSaveParams() {
    zfree(server.saveparams);
    server.saveparams = NULL;
    server.saveparamslen = 0;
}

void loadServerConfigFromString(char *config) {
    char *err = NULL;
    int linenum = 0, totlines, i;
    sds *lines;

    lines = sdssplitlen(config,strlen(config),"\n",1,&totlines);

    for (i = 0; i < totlines; i++) {
        sds *argv;
        int argc;

        linenum = i+1;
        lines[i] = sdstrim(lines[i]," \t\r\n");

        /* Skip comments and blank lines */
        if (lines[i][0] == '#' || lines[i][0] == '\0') continue;

        /* Split into arguments */
        argv = sdssplitargs(lines[i],&argc);
        if (argv == NULL) {
            err = "Unbalanced quotes in configuration line";
            goto loaderr;
        }

        /* Skip this line if the resulting command vector is empty. */
        if (argc == 0) {
            sdsfreesplitres(argv,argc);
            return;
        }
        sdstolower(argv[0]);

        /* Execute config directives */
        if (!strcasecmp(argv[0],"timeout") && argc == 2) {
            server.maxidletime = atoi(argv[1]);
            if (server.maxidletime < 0) {
                err = "Invalid timeout value"; goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"tcp-keepalive") && argc == 2) {
            server.tcpkeepalive = atoi(argv[1]);
            if (server.tcpkeepalive < 0) {
                err = "Invalid tcp-keepalive value"; goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"port") && argc == 2) {
            server.port = atoi(argv[1]);
            if (server.port < 0 || server.port > 65535) {
                err = "Invalid port"; goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"bind") && argc == 2) {
            server.bindaddr = zstrdup(argv[1]);
        } else if (!strcasecmp(argv[0],"unixsocket") && argc == 2) {
            server.unixsocket = zstrdup(argv[1]);
        } else if (!strcasecmp(argv[0],"unixsocketperm") && argc == 2) {
            errno = 0;
            server.unixsocketperm = (mode_t)strtol(argv[1], NULL, 8);
            if (errno || server.unixsocketperm > 0777) {
                err = "Invalid socket file permissions"; goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"save")) {
            if (argc == 3) {
                int seconds = atoi(argv[1]);
                int changes = atoi(argv[2]);
                if (seconds < 1 || changes < 0) {
                    err = "Invalid save parameters"; goto loaderr;
                }
                appendServerSaveParams(seconds,changes);
            } else if (argc == 2 && !strcasecmp(argv[1],"")) {
                resetServerSaveParams();
            }
        } else if (!strcasecmp(argv[0],"dir") && argc == 2) {
            if (chdir(argv[1]) == -1) {
                redisLog(REDIS_WARNING,"Can't chdir to '%s': %s",
                    argv[1], strerror(errno));
                exit(1);
            }
        } else if (!strcasecmp(argv[0],"loglevel") && argc == 2) {
            if (!strcasecmp(argv[1],"debug")) server.verbosity = REDIS_DEBUG;
            else if (!strcasecmp(argv[1],"verbose")) server.verbosity = REDIS_VERBOSE;
            else if (!strcasecmp(argv[1],"notice")) server.verbosity = REDIS_NOTICE;
            else if (!strcasecmp(argv[1],"warning")) server.verbosity = REDIS_WARNING;
            else {
                err = "Invalid log level. Must be one of debug, notice, warning";
                goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"logfile") && argc == 2) {
            FILE *logfp;

            server.logfile = zstrdup(argv[1]);
            if (!strcasecmp(server.logfile,"stdout")) {
                zfree(server.logfile);
                server.logfile = NULL;
            }
            if (server.logfile) {
                /* Test if we are able to open the file. The server will not
                 * be able to abort just for this problem later... */
                logfp = fopen(server.logfile,"a");
                if (logfp == NULL) {
                    err = sdscatprintf(sdsempty(),
                        "Can't open the log file: %s", strerror(errno));
                    goto loaderr;
                }
                fclose(logfp);
            }
        } else if (!strcasecmp(argv[0],"syslog-enabled") && argc == 2) {
            if ((server.syslog_enabled = yesnotoi(argv[1])) == -1) {
                err = "argument must be 'yes' or 'no'"; goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"syslog-ident") && argc == 2) {
            if (server.syslog_ident) zfree(server.syslog_ident);
            server.syslog_ident = zstrdup(argv[1]);
        } else if (!strcasecmp(argv[0],"syslog-facility") && argc == 2) {
            int i;

            for (i = 0; validSyslogFacilities[i].name; i++) {
                if (!strcasecmp(validSyslogFacilities[i].name, argv[1])) {
                    server.syslog_facility = validSyslogFacilities[i].value;
                    break;
                }
            }

            if (!validSyslogFacilities[i].name) {
                err = "Invalid log facility. Must be one of USER or between LOCAL0-LOCAL7";
                goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"databases") && argc == 2) {
            server.dbnum = atoi(argv[1]);
            if (server.dbnum < 1) {
                err = "Invalid number of databases"; goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"include") && argc == 2) {
            loadServerConfig(argv[1],NULL);
        } else if (!strcasecmp(argv[0],"maxclients") && argc == 2) {
            server.maxclients = atoi(argv[1]);
            if (server.maxclients < 1) {
                err = "Invalid max clients limit"; goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"maxmemory") && argc == 2) {
            server.maxmemory = memtoll(argv[1],NULL);
        } else if (!strcasecmp(argv[0],"maxmemory-policy") && argc == 2) {
            if (!strcasecmp(argv[1],"volatile-lru")) {
                server.maxmemory_policy = REDIS_MAXMEMORY_VOLATILE_LRU;
            } else if (!strcasecmp(argv[1],"volatile-random")) {
                server.maxmemory_policy = REDIS_MAXMEMORY_VOLATILE_RANDOM;
            } else if (!strcasecmp(argv[1],"volatile-ttl")) {
                server.maxmemory_policy = REDIS_MAXMEMORY_VOLATILE_TTL;
            } else if (!strcasecmp(argv[1],"allkeys-lru")) {
                server.maxmemory_policy = REDIS_MAXMEMORY_ALLKEYS_LRU;
            } else if (!strcasecmp(argv[1],"allkeys-random")) {
                server.maxmemory_policy = REDIS_MAXMEMORY_ALLKEYS_RANDOM;
            } else if (!strcasecmp(argv[1],"noeviction")) {
                server.maxmemory_policy = REDIS_MAXMEMORY_NO_EVICTION;
            } else {
                err = "Invalid maxmemory policy";
                goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"maxmemory-samples") && argc == 2) {
            server.maxmemory_samples = atoi(argv[1]);
            if (server.maxmemory_samples <= 0) {
                err = "maxmemory-samples must be 1 or greater";
                goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"slaveof") && argc == 3) {
            server.masterhost = sdsnew(argv[1]);
            server.masterport = atoi(argv[2]);
            server.repl_state = REDIS_REPL_CONNECT;
        } else if (!strcasecmp(argv[0],"repl-ping-slave-period") && argc == 2) {
            server.repl_ping_slave_period = atoi(argv[1]);
            if (server.repl_ping_slave_period <= 0) {
                err = "repl-ping-slave-period must be 1 or greater";
                goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"repl-timeout") && argc == 2) {
            server.repl_timeout = atoi(argv[1]);
            if (server.repl_timeout <= 0) {
                err = "repl-timeout must be 1 or greater";
                goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"repl-disable-tcp-nodelay") && argc==2) {
            if ((server.repl_disable_tcp_nodelay = yesnotoi(argv[1])) == -1) {
                err = "argument must be 'yes' or 'no'"; goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"repl-backlog-size") && argc == 2) {
            long long size = strtoll(argv[1],NULL,10);
            if (size <= 0) {
                err = "repl-backlog-size must be 1 or greater.";
                goto loaderr;
            }
            resizeReplicationBacklog(size);
        } else if (!strcasecmp(argv[0],"repl-backlog-ttl") && argc == 2) {
            server.repl_backlog_time_limit = atoi(argv[1]);
            if (server.repl_backlog_time_limit < 0) {
                err = "repl-backlog-ttl can't be negative ";
                goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"masterauth") && argc == 2) {
        	server.masterauth = zstrdup(argv[1]);
        } else if (!strcasecmp(argv[0],"slave-serve-stale-data") && argc == 2) {
            if ((server.repl_serve_stale_data = yesnotoi(argv[1])) == -1) {
                err = "argument must be 'yes' or 'no'"; goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"slave-read-only") && argc == 2) {
            if ((server.repl_slave_ro = yesnotoi(argv[1])) == -1) {
                err = "argument must be 'yes' or 'no'"; goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"rdbcompression") && argc == 2) {
            if ((server.rdb_compression = yesnotoi(argv[1])) == -1) {
                err = "argument must be 'yes' or 'no'"; goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"rdbchecksum") && argc == 2) {
            if ((server.rdb_checksum = yesnotoi(argv[1])) == -1) {
                err = "argument must be 'yes' or 'no'"; goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"activerehashing") && argc == 2) {
            if ((server.activerehashing = yesnotoi(argv[1])) == -1) {
                err = "argument must be 'yes' or 'no'"; goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"daemonize") && argc == 2) {
            if ((server.daemonize = yesnotoi(argv[1])) == -1) {
                err = "argument must be 'yes' or 'no'"; goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"hz") && argc == 2) {
            server.hz = atoi(argv[1]);
            if (server.hz < REDIS_MIN_HZ) server.hz = REDIS_MIN_HZ;
            if (server.hz > REDIS_MAX_HZ) server.hz = REDIS_MAX_HZ;
        } else if (!strcasecmp(argv[0],"appendonly") && argc == 2) {
            int yes;

            if ((yes = yesnotoi(argv[1])) == -1) {
                err = "argument must be 'yes' or 'no'"; goto loaderr;
            }
            server.aof_state = yes ? REDIS_AOF_ON : REDIS_AOF_OFF;
        } else if (!strcasecmp(argv[0],"appendfilename") && argc == 2) {
            zfree(server.aof_filename);
            server.aof_filename = zstrdup(argv[1]);
        } else if (!strcasecmp(argv[0],"no-appendfsync-on-rewrite")
                   && argc == 2) {
            if ((server.aof_no_fsync_on_rewrite= yesnotoi(argv[1])) == -1) {
                err = "argument must be 'yes' or 'no'"; goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"appendfsync") && argc == 2) {
            if (!strcasecmp(argv[1],"no")) {
                server.aof_fsync = AOF_FSYNC_NO;
            } else if (!strcasecmp(argv[1],"always")) {
                server.aof_fsync = AOF_FSYNC_ALWAYS;
            } else if (!strcasecmp(argv[1],"everysec")) {
                server.aof_fsync = AOF_FSYNC_EVERYSEC;
            } else {
                err = "argument must be 'no', 'always' or 'everysec'";
                goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"auto-aof-rewrite-percentage") &&
                   argc == 2)
        {
            server.aof_rewrite_perc = atoi(argv[1]);
            if (server.aof_rewrite_perc < 0) {
                err = "Invalid negative percentage for AOF auto rewrite";
                goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"auto-aof-rewrite-min-size") &&
                   argc == 2)
        {
            server.aof_rewrite_min_size = memtoll(argv[1],NULL);
        } else if (!strcasecmp(argv[0],"aof-rewrite-incremental-fsync") &&
                   argc == 2)
        {
            if ((server.aof_rewrite_incremental_fsync = yesnotoi(argv[1])) == -1) {
                err = "argument must be 'yes' or 'no'"; goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"requirepass") && argc == 2) {
            if (strlen(argv[1]) > REDIS_AUTHPASS_MAX_LEN) {
                err = "Password is longer than REDIS_AUTHPASS_MAX_LEN";
                goto loaderr;
            }
            server.requirepass = zstrdup(argv[1]);
        } else if (!strcasecmp(argv[0],"pidfile") && argc == 2) {
            zfree(server.pidfile);
            server.pidfile = zstrdup(argv[1]);
        } else if (!strcasecmp(argv[0],"dbfilename") && argc == 2) {
            zfree(server.rdb_filename);
            server.rdb_filename = zstrdup(argv[1]);
        } else if (!strcasecmp(argv[0],"hash-max-ziplist-entries") && argc == 2) {
            server.hash_max_ziplist_entries = memtoll(argv[1], NULL);
        } else if (!strcasecmp(argv[0],"hash-max-ziplist-value") && argc == 2) {
            server.hash_max_ziplist_value = memtoll(argv[1], NULL);
        } else if (!strcasecmp(argv[0],"list-max-ziplist-entries") && argc == 2){
            server.list_max_ziplist_entries = memtoll(argv[1], NULL);
        } else if (!strcasecmp(argv[0],"list-max-ziplist-value") && argc == 2) {
            server.list_max_ziplist_value = memtoll(argv[1], NULL);
        } else if (!strcasecmp(argv[0],"set-max-intset-entries") && argc == 2) {
            server.set_max_intset_entries = memtoll(argv[1], NULL);
        } else if (!strcasecmp(argv[0],"zset-max-ziplist-entries") && argc == 2) {
            server.zset_max_ziplist_entries = memtoll(argv[1], NULL);
        } else if (!strcasecmp(argv[0],"zset-max-ziplist-value") && argc == 2) {
            server.zset_max_ziplist_value = memtoll(argv[1], NULL);
        } else if (!strcasecmp(argv[0],"rename-command") && argc == 3) {
            struct redisCommand *cmd = lookupCommand(argv[1]);
            int retval;

            if (!cmd) {
                err = "No such command in rename-command";
                goto loaderr;
            }

            /* If the target command name is the empty string we just
             * remove it from the command table. */
            retval = dictDelete(server.commands, argv[1]);
            redisAssert(retval == DICT_OK);

            /* Otherwise we re-add the command under a different name. */
            if (sdslen(argv[2]) != 0) {
                sds copy = sdsdup(argv[2]);

                retval = dictAdd(server.commands, copy, cmd);
                if (retval != DICT_OK) {
                    sdsfree(copy);
                    err = "Target command name already exists"; goto loaderr;
                }
            }
        } else if (!strcasecmp(argv[0],"lua-time-limit") && argc == 2) {
            server.lua_time_limit = strtoll(argv[1],NULL,10);
        } else if (!strcasecmp(argv[0],"slowlog-log-slower-than") &&
                   argc == 2)
        {
            server.slowlog_log_slower_than = strtoll(argv[1],NULL,10);
        } else if (!strcasecmp(argv[0],"slowlog-max-len") && argc == 2) {
            server.slowlog_max_len = strtoll(argv[1],NULL,10);
        } else if (!strcasecmp(argv[0],"client-output-buffer-limit") &&
                   argc == 5)
        {
            int class = getClientLimitClassByName(argv[1]);
            unsigned long long hard, soft;
            int soft_seconds;

            if (class == -1) {
                err = "Unrecognized client limit class";
                goto loaderr;
            }
            hard = memtoll(argv[2],NULL);
            soft = memtoll(argv[3],NULL);
            soft_seconds = atoi(argv[4]);
            if (soft_seconds < 0) {
                err = "Negative number of seconds in soft limit is invalid";
                goto loaderr;
            }
            server.client_obuf_limits[class].hard_limit_bytes = hard;
            server.client_obuf_limits[class].soft_limit_bytes = soft;
            server.client_obuf_limits[class].soft_limit_seconds = soft_seconds;
        } else if (!strcasecmp(argv[0],"stop-writes-on-bgsave-error") &&
                   argc == 2) {
            if ((server.stop_writes_on_bgsave_err = yesnotoi(argv[1])) == -1) {
                err = "argument must be 'yes' or 'no'"; goto loaderr;
            }
        } else if (!strcasecmp(argv[0],"slave-priority") && argc == 2) {
            server.slave_priority = atoi(argv[1]);
        } else if (!strcasecmp(argv[0],"notify-keyspace-events") && argc == 2) {
            int flags = keyspaceEventsStringToFlags(argv[1]);

            if (flags == -1) {
                err = "Invalid event class character. Use 'g$lshzxeA'.";
                goto loaderr;
            }
            server.notify_keyspace_events = flags;
        } else if (!strcasecmp(argv[0],"sentinel")) {
            /* argc == 1 is handled by main() as we need to enter the sentinel
             * mode ASAP. */
            if (argc != 1) {
                if (!server.sentinel_mode) {
                    err = "sentinel directive while not in sentinel mode";
                    goto loaderr;
                }
                err = sentinelHandleConfiguration(argv+1,argc-1);
                if (err) goto loaderr;
            }
        } else {
            err = "Bad directive or wrong number of arguments"; goto loaderr;
        }
        sdsfreesplitres(argv,argc);
    }
    sdsfreesplitres(lines,totlines);
    return;

loaderr:
    fprintf(stderr, "\n*** FATAL CONFIG FILE ERROR ***\n");
    fprintf(stderr, "Reading the configuration file, at line %d\n", linenum);
    fprintf(stderr, ">>> '%s'\n", lines[i]);
    fprintf(stderr, "%s\n", err);
    exit(1);
}

/* Load the server configuration from the specified filename.
 * The function appends the additional configuration directives stored
 * in the 'options' string to the config file before loading.
 *
 * Both filename and options can be NULL, in such a case are considered
 * empty. This way loadServerConfig can be used to just load a file or
 * just load a string. */
void loadServerConfig(char *filename, char *options) {
    sds config = sdsempty();
    char buf[REDIS_CONFIGLINE_MAX+1];

    /* Load the file content */
    if (filename) {
        FILE *fp;

        if (filename[0] == '-' && filename[1] == '\0') {
            fp = stdin;
        } else {
            if ((fp = fopen(filename,"r")) == NULL) {
                redisLog(REDIS_WARNING,
                    "Fatal error, can't open config file '%s'", filename);
                exit(1);
            }
        }
        while(fgets(buf,REDIS_CONFIGLINE_MAX+1,fp) != NULL)
            config = sdscat(config,buf);
        if (fp != stdin) fclose(fp);
    }
    /* Append the additional options */
    if (options) {
        config = sdscat(config,"\n");
        config = sdscat(config,options);
    }
    loadServerConfigFromString(config);
    sdsfree(config);
}

/*-----------------------------------------------------------------------------
 * CONFIG SET implementation
 *----------------------------------------------------------------------------*/

void configSetCommand(redisClient *c) {
    robj *o;
    long long ll;
    redisAssertWithInfo(c,c->argv[2],c->argv[2]->encoding == REDIS_ENCODING_RAW);
    redisAssertWithInfo(c,c->argv[2],c->argv[3]->encoding == REDIS_ENCODING_RAW);
    o = c->argv[3];

    if (!strcasecmp(c->argv[2]->ptr,"dbfilename")) {
        zfree(server.rdb_filename);
        server.rdb_filename = zstrdup(o->ptr);
    } else if (!strcasecmp(c->argv[2]->ptr,"requirepass")) {
        if (sdslen(o->ptr) > REDIS_AUTHPASS_MAX_LEN) goto badfmt;
        zfree(server.requirepass);
        server.requirepass = ((char*)o->ptr)[0] ? zstrdup(o->ptr) : NULL;
    } else if (!strcasecmp(c->argv[2]->ptr,"masterauth")) {
        zfree(server.masterauth);
        server.masterauth = ((char*)o->ptr)[0] ? zstrdup(o->ptr) : NULL;
    } else if (!strcasecmp(c->argv[2]->ptr,"maxmemory")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR ||
            ll < 0) goto badfmt;
        server.maxmemory = ll;
        if (server.maxmemory) {
            if (server.maxmemory < zmalloc_used_memory()) {
                redisLog(REDIS_WARNING,"WARNING: the new maxmemory value set via CONFIG SET is smaller than the current memory usage. This will result in keys eviction and/or inability to accept new write commands depending on the maxmemory-policy.");
            }
            freeMemoryIfNeeded();
        }
    } else if (!strcasecmp(c->argv[2]->ptr,"hz")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR ||
            ll < 0) goto badfmt;
        server.hz = (int) ll;
        if (server.hz < REDIS_MIN_HZ) server.hz = REDIS_MIN_HZ;
        if (server.hz > REDIS_MAX_HZ) server.hz = REDIS_MAX_HZ;
    } else if (!strcasecmp(c->argv[2]->ptr,"maxmemory-policy")) {
        if (!strcasecmp(o->ptr,"volatile-lru")) {
            server.maxmemory_policy = REDIS_MAXMEMORY_VOLATILE_LRU;
        } else if (!strcasecmp(o->ptr,"volatile-random")) {
            server.maxmemory_policy = REDIS_MAXMEMORY_VOLATILE_RANDOM;
        } else if (!strcasecmp(o->ptr,"volatile-ttl")) {
            server.maxmemory_policy = REDIS_MAXMEMORY_VOLATILE_TTL;
        } else if (!strcasecmp(o->ptr,"allkeys-lru")) {
            server.maxmemory_policy = REDIS_MAXMEMORY_ALLKEYS_LRU;
        } else if (!strcasecmp(o->ptr,"allkeys-random")) {
            server.maxmemory_policy = REDIS_MAXMEMORY_ALLKEYS_RANDOM;
        } else if (!strcasecmp(o->ptr,"noeviction")) {
            server.maxmemory_policy = REDIS_MAXMEMORY_NO_EVICTION;
        } else {
            goto badfmt;
        }
    } else if (!strcasecmp(c->argv[2]->ptr,"maxmemory-samples")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR ||
            ll <= 0) goto badfmt;
        server.maxmemory_samples = ll;
    } else if (!strcasecmp(c->argv[2]->ptr,"timeout")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR ||
            ll < 0 || ll > LONG_MAX) goto badfmt;
        server.maxidletime = ll;
    } else if (!strcasecmp(c->argv[2]->ptr,"tcp-keepalive")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR ||
            ll < 0 || ll > INT_MAX) goto badfmt;
        server.tcpkeepalive = ll;
    } else if (!strcasecmp(c->argv[2]->ptr,"appendfsync")) {
        if (!strcasecmp(o->ptr,"no")) {
            server.aof_fsync = AOF_FSYNC_NO;
        } else if (!strcasecmp(o->ptr,"everysec")) {
            server.aof_fsync = AOF_FSYNC_EVERYSEC;
        } else if (!strcasecmp(o->ptr,"always")) {
            server.aof_fsync = AOF_FSYNC_ALWAYS;
        } else {
            goto badfmt;
        }
    } else if (!strcasecmp(c->argv[2]->ptr,"no-appendfsync-on-rewrite")) {
        int yn = yesnotoi(o->ptr);

        if (yn == -1) goto badfmt;
        server.aof_no_fsync_on_rewrite = yn;
    } else if (!strcasecmp(c->argv[2]->ptr,"appendonly")) {
        int enable = yesnotoi(o->ptr);

        if (enable == -1) goto badfmt;
        if (enable == 0 && server.aof_state != REDIS_AOF_OFF) {
            stopAppendOnly();
        } else if (enable && server.aof_state == REDIS_AOF_OFF) {
            if (startAppendOnly() == REDIS_ERR) {
                addReplyError(c,
                    "Unable to turn on AOF. Check server logs.");
                return;
            }
        }
    } else if (!strcasecmp(c->argv[2]->ptr,"auto-aof-rewrite-percentage")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR || ll < 0) goto badfmt;
        server.aof_rewrite_perc = ll;
    } else if (!strcasecmp(c->argv[2]->ptr,"auto-aof-rewrite-min-size")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR || ll < 0) goto badfmt;
        server.aof_rewrite_min_size = ll;
    } else if (!strcasecmp(c->argv[2]->ptr,"aof-rewrite-incremental-fsync")) {
        int yn = yesnotoi(o->ptr);

        if (yn == -1) goto badfmt;
        server.aof_rewrite_incremental_fsync = yn;
    } else if (!strcasecmp(c->argv[2]->ptr,"save")) {
        int vlen, j;
        sds *v = sdssplitlen(o->ptr,sdslen(o->ptr)," ",1,&vlen);

        /* Perform sanity check before setting the new config:
         * - Even number of args
         * - Seconds >= 1, changes >= 0 */
        if (vlen & 1) {
            sdsfreesplitres(v,vlen);
            goto badfmt;
        }
        for (j = 0; j < vlen; j++) {
            char *eptr;
            long val;

            val = strtoll(v[j], &eptr, 10);
            if (eptr[0] != '\0' ||
                ((j & 1) == 0 && val < 1) ||
                ((j & 1) == 1 && val < 0)) {
                sdsfreesplitres(v,vlen);
                goto badfmt;
            }
        }
        /* Finally set the new config */
        resetServerSaveParams();
        for (j = 0; j < vlen; j += 2) {
            time_t seconds;
            int changes;

            seconds = strtoll(v[j],NULL,10);
            changes = strtoll(v[j+1],NULL,10);
            appendServerSaveParams(seconds, changes);
        }
        sdsfreesplitres(v,vlen);
    } else if (!strcasecmp(c->argv[2]->ptr,"slave-serve-stale-data")) {
        int yn = yesnotoi(o->ptr);

        if (yn == -1) goto badfmt;
        server.repl_serve_stale_data = yn;
    } else if (!strcasecmp(c->argv[2]->ptr,"slave-read-only")) {
        int yn = yesnotoi(o->ptr);

        if (yn == -1) goto badfmt;
        server.repl_slave_ro = yn;
    } else if (!strcasecmp(c->argv[2]->ptr,"dir")) {
        if (chdir((char*)o->ptr) == -1) {
            addReplyErrorFormat(c,"Changing directory: %s", strerror(errno));
            return;
        }
    } else if (!strcasecmp(c->argv[2]->ptr,"hash-max-ziplist-entries")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR || ll < 0) goto badfmt;
        server.hash_max_ziplist_entries = ll;
    } else if (!strcasecmp(c->argv[2]->ptr,"hash-max-ziplist-value")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR || ll < 0) goto badfmt;
        server.hash_max_ziplist_value = ll;
    } else if (!strcasecmp(c->argv[2]->ptr,"list-max-ziplist-entries")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR || ll < 0) goto badfmt;
        server.list_max_ziplist_entries = ll;
    } else if (!strcasecmp(c->argv[2]->ptr,"list-max-ziplist-value")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR || ll < 0) goto badfmt;
        server.list_max_ziplist_value = ll;
    } else if (!strcasecmp(c->argv[2]->ptr,"set-max-intset-entries")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR || ll < 0) goto badfmt;
        server.set_max_intset_entries = ll;
    } else if (!strcasecmp(c->argv[2]->ptr,"zset-max-ziplist-entries")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR || ll < 0) goto badfmt;
        server.zset_max_ziplist_entries = ll;
    } else if (!strcasecmp(c->argv[2]->ptr,"zset-max-ziplist-value")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR || ll < 0) goto badfmt;
        server.zset_max_ziplist_value = ll;
    } else if (!strcasecmp(c->argv[2]->ptr,"lua-time-limit")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR || ll < 0) goto badfmt;
        server.lua_time_limit = ll;
    } else if (!strcasecmp(c->argv[2]->ptr,"slowlog-log-slower-than")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR) goto badfmt;
        server.slowlog_log_slower_than = ll;
    } else if (!strcasecmp(c->argv[2]->ptr,"slowlog-max-len")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR || ll < 0) goto badfmt;
        server.slowlog_max_len = (unsigned)ll;
    } else if (!strcasecmp(c->argv[2]->ptr,"loglevel")) {
        if (!strcasecmp(o->ptr,"warning")) {
            server.verbosity = REDIS_WARNING;
        } else if (!strcasecmp(o->ptr,"notice")) {
            server.verbosity = REDIS_NOTICE;
        } else if (!strcasecmp(o->ptr,"verbose")) {
            server.verbosity = REDIS_VERBOSE;
        } else if (!strcasecmp(o->ptr,"debug")) {
            server.verbosity = REDIS_DEBUG;
        } else {
            goto badfmt;
        }
    } else if (!strcasecmp(c->argv[2]->ptr,"client-output-buffer-limit")) {
        int vlen, j;
        sds *v = sdssplitlen(o->ptr,sdslen(o->ptr)," ",1,&vlen);

        /* We need a multiple of 4: <class> <hard> <soft> <soft_seconds> */
        if (vlen % 4) {
            sdsfreesplitres(v,vlen);
            goto badfmt;
        }

        /* Sanity check of single arguments, so that we either refuse the
         * whole configuration string or accept it all, even if a single
         * error in a single client class is present. */
        for (j = 0; j < vlen; j++) {
            char *eptr;
            long val;

            if ((j % 4) == 0) {
                if (getClientLimitClassByName(v[j]) == -1) {
                    sdsfreesplitres(v,vlen);
                    goto badfmt;
                }
            } else {
                val = strtoll(v[j], &eptr, 10);
                if (eptr[0] != '\0' || val < 0) {
                    sdsfreesplitres(v,vlen);
                    goto badfmt;
                }
            }
        }
        /* Finally set the new config */
        for (j = 0; j < vlen; j += 4) {
            int class;
            unsigned long long hard, soft;
            int soft_seconds;

            class = getClientLimitClassByName(v[j]);
            hard = strtoll(v[j+1],NULL,10);
            soft = strtoll(v[j+2],NULL,10);
            soft_seconds = strtoll(v[j+3],NULL,10);

            server.client_obuf_limits[class].hard_limit_bytes = hard;
            server.client_obuf_limits[class].soft_limit_bytes = soft;
            server.client_obuf_limits[class].soft_limit_seconds = soft_seconds;
        }
        sdsfreesplitres(v,vlen);
    } else if (!strcasecmp(c->argv[2]->ptr,"stop-writes-on-bgsave-error")) {
        int yn = yesnotoi(o->ptr);

        if (yn == -1) goto badfmt;
        server.stop_writes_on_bgsave_err = yn;
    } else if (!strcasecmp(c->argv[2]->ptr,"repl-ping-slave-period")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR || ll <= 0) goto badfmt;
        server.repl_ping_slave_period = ll;
    } else if (!strcasecmp(c->argv[2]->ptr,"repl-timeout")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR || ll <= 0) goto badfmt;
        server.repl_timeout = ll;
    } else if (!strcasecmp(c->argv[2]->ptr,"repl-backlog-size")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR || ll <= 0) goto badfmt;
        resizeReplicationBacklog(ll);
    } else if (!strcasecmp(c->argv[2]->ptr,"repl-backlog-ttl")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR || ll < 0) goto badfmt;
        server.repl_backlog_time_limit = ll;
    } else if (!strcasecmp(c->argv[2]->ptr,"watchdog-period")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR || ll < 0) goto badfmt;
        if (ll)
            enableWatchdog(ll);
        else
            disableWatchdog();
    } else if (!strcasecmp(c->argv[2]->ptr,"rdbcompression")) {
        int yn = yesnotoi(o->ptr);

        if (yn == -1) goto badfmt;
        server.rdb_compression = yn;
    } else if (!strcasecmp(c->argv[2]->ptr,"notify-keyspace-events")) {
        int flags = keyspaceEventsStringToFlags(o->ptr);

        if (flags == -1) goto badfmt;
        server.notify_keyspace_events = flags;
    } else if (!strcasecmp(c->argv[2]->ptr,"repl-disable-tcp-nodelay")) {
        int yn = yesnotoi(o->ptr);

        if (yn == -1) goto badfmt;
        server.repl_disable_tcp_nodelay = yn;
    } else if (!strcasecmp(c->argv[2]->ptr,"slave-priority")) {
        if (getLongLongFromObject(o,&ll) == REDIS_ERR ||
            ll <= 0) goto badfmt;
        server.slave_priority = ll;
    } else {
        addReplyErrorFormat(c,"Unsupported CONFIG parameter: %s",
            (char*)c->argv[2]->ptr);
        return;
    }
    addReply(c,shared.ok);
    return;

badfmt: /* Bad format errors */
    addReplyErrorFormat(c,"Invalid argument '%s' for CONFIG SET '%s'",
            (char*)o->ptr,
            (char*)c->argv[2]->ptr);
}

/*-----------------------------------------------------------------------------
 * CONFIG GET implementation
 *----------------------------------------------------------------------------*/

#define config_get_string_field(_name,_var) do { \
    if (stringmatch(pattern,_name,0)) { \
        addReplyBulkCString(c,_name); \
        addReplyBulkCString(c,_var ? _var : ""); \
        matches++; \
    } \
} while(0);

#define config_get_bool_field(_name,_var) do { \
    if (stringmatch(pattern,_name,0)) { \
        addReplyBulkCString(c,_name); \
        addReplyBulkCString(c,_var ? "yes" : "no"); \
        matches++; \
    } \
} while(0);

#define config_get_numerical_field(_name,_var) do { \
    if (stringmatch(pattern,_name,0)) { \
        ll2string(buf,sizeof(buf),_var); \
        addReplyBulkCString(c,_name); \
        addReplyBulkCString(c,buf); \
        matches++; \
    } \
} while(0);

void configGetCommand(redisClient *c) {
    robj *o = c->argv[2];
    void *replylen = addDeferredMultiBulkLength(c);
    char *pattern = o->ptr;
    char buf[128];
    int matches = 0;
    redisAssertWithInfo(c,o,o->encoding == REDIS_ENCODING_RAW);

    /* String values */
    config_get_string_field("dbfilename",server.rdb_filename);
    config_get_string_field("requirepass",server.requirepass);
    config_get_string_field("masterauth",server.masterauth);
    config_get_string_field("bind",server.bindaddr);
    config_get_string_field("unixsocket",server.unixsocket);
    config_get_string_field("logfile",server.logfile);
    config_get_string_field("pidfile",server.pidfile);

    /* Numerical values */
    config_get_numerical_field("maxmemory",server.maxmemory);
    config_get_numerical_field("maxmemory-samples",server.maxmemory_samples);
    config_get_numerical_field("timeout",server.maxidletime);
    config_get_numerical_field("tcp-keepalive",server.tcpkeepalive);
    config_get_numerical_field("auto-aof-rewrite-percentage",
            server.aof_rewrite_perc);
    config_get_numerical_field("auto-aof-rewrite-min-size",
            server.aof_rewrite_min_size);
    config_get_numerical_field("hash-max-ziplist-entries",
            server.hash_max_ziplist_entries);
    config_get_numerical_field("hash-max-ziplist-value",
            server.hash_max_ziplist_value);
    config_get_numerical_field("list-max-ziplist-entries",
            server.list_max_ziplist_entries);
    config_get_numerical_field("list-max-ziplist-value",
            server.list_max_ziplist_value);
    config_get_numerical_field("set-max-intset-entries",
            server.set_max_intset_entries);
    config_get_numerical_field("zset-max-ziplist-entries",
            server.zset_max_ziplist_entries);
    config_get_numerical_field("zset-max-ziplist-value",
            server.zset_max_ziplist_value);
    config_get_numerical_field("lua-time-limit",server.lua_time_limit);
    config_get_numerical_field("slowlog-log-slower-than",
            server.slowlog_log_slower_than);
    config_get_numerical_field("slowlog-max-len",
            server.slowlog_max_len);
    config_get_numerical_field("port",server.port);
    config_get_numerical_field("databases",server.dbnum);
    config_get_numerical_field("repl-ping-slave-period",server.repl_ping_slave_period);
    config_get_numerical_field("repl-timeout",server.repl_timeout);
    config_get_numerical_field("repl-backlog-size",server.repl_backlog_size);
    config_get_numerical_field("repl-backlog-ttl",server.repl_backlog_time_limit);
    config_get_numerical_field("maxclients",server.maxclients);
    config_get_numerical_field("watchdog-period",server.watchdog_period);
    config_get_numerical_field("slave-priority",server.slave_priority);
    config_get_numerical_field("hz",server.hz);

    /* Bool (yes/no) values */
    config_get_bool_field("no-appendfsync-on-rewrite",
            server.aof_no_fsync_on_rewrite);
    config_get_bool_field("slave-serve-stale-data",
            server.repl_serve_stale_data);
    config_get_bool_field("slave-read-only",
            server.repl_slave_ro);
    config_get_bool_field("stop-writes-on-bgsave-error",
            server.stop_writes_on_bgsave_err);
    config_get_bool_field("daemonize", server.daemonize);
    config_get_bool_field("rdbcompression", server.rdb_compression);
    config_get_bool_field("rdbchecksum", server.rdb_checksum);
    config_get_bool_field("activerehashing", server.activerehashing);
    config_get_bool_field("repl-disable-tcp-nodelay",
            server.repl_disable_tcp_nodelay);
    config_get_bool_field("aof-rewrite-incremental-fsync",
            server.aof_rewrite_incremental_fsync);

    /* Everything we can't handle with macros follows. */

    if (stringmatch(pattern,"appendonly",0)) {
        addReplyBulkCString(c,"appendonly");
        addReplyBulkCString(c,server.aof_state == REDIS_AOF_OFF ? "no" : "yes");
        matches++;
    }
    if (stringmatch(pattern,"dir",0)) {
        char buf[1024];

        if (getcwd(buf,sizeof(buf)) == NULL)
            buf[0] = '\0';

        addReplyBulkCString(c,"dir");
        addReplyBulkCString(c,buf);
        matches++;
    }
    if (stringmatch(pattern,"maxmemory-policy",0)) {
        char *s;

        switch(server.maxmemory_policy) {
        case REDIS_MAXMEMORY_VOLATILE_LRU: s = "volatile-lru"; break;
        case REDIS_MAXMEMORY_VOLATILE_TTL: s = "volatile-ttl"; break;
        case REDIS_MAXMEMORY_VOLATILE_RANDOM: s = "volatile-random"; break;
        case REDIS_MAXMEMORY_ALLKEYS_LRU: s = "allkeys-lru"; break;
        case REDIS_MAXMEMORY_ALLKEYS_RANDOM: s = "allkeys-random"; break;
        case REDIS_MAXMEMORY_NO_EVICTION: s = "noeviction"; break;
        default: s = "unknown"; break; /* too harmless to panic */
        }
        addReplyBulkCString(c,"maxmemory-policy");
        addReplyBulkCString(c,s);
        matches++;
    }
    if (stringmatch(pattern,"appendfsync",0)) {
        char *policy;

        switch(server.aof_fsync) {
        case AOF_FSYNC_NO: policy = "no"; break;
        case AOF_FSYNC_EVERYSEC: policy = "everysec"; break;
        case AOF_FSYNC_ALWAYS: policy = "always"; break;
        default: policy = "unknown"; break; /* too harmless to panic */
        }
        addReplyBulkCString(c,"appendfsync");
        addReplyBulkCString(c,policy);
        matches++;
    }
    if (stringmatch(pattern,"save",0)) {
        sds buf = sdsempty();
        int j;

        for (j = 0; j < server.saveparamslen; j++) {
            buf = sdscatprintf(buf,"%ld %d",
                    server.saveparams[j].seconds,
                    server.saveparams[j].changes);
            if (j != server.saveparamslen-1)
                buf = sdscatlen(buf," ",1);
        }
        addReplyBulkCString(c,"save");
        addReplyBulkCString(c,buf);
        sdsfree(buf);
        matches++;
    }
    if (stringmatch(pattern,"loglevel",0)) {
        char *s;

        switch(server.verbosity) {
        case REDIS_WARNING: s = "warning"; break;
        case REDIS_VERBOSE: s = "verbose"; break;
        case REDIS_NOTICE: s = "notice"; break;
        case REDIS_DEBUG: s = "debug"; break;
        default: s = "unknown"; break; /* too harmless to panic */
        }
        addReplyBulkCString(c,"loglevel");
        addReplyBulkCString(c,s);
        matches++;
    }
    if (stringmatch(pattern,"client-output-buffer-limit",0)) {
        sds buf = sdsempty();
        int j;

        for (j = 0; j < REDIS_CLIENT_LIMIT_NUM_CLASSES; j++) {
            buf = sdscatprintf(buf,"%s %llu %llu %ld",
                    getClientLimitClassName(j),
                    server.client_obuf_limits[j].hard_limit_bytes,
                    server.client_obuf_limits[j].soft_limit_bytes,
                    (long) server.client_obuf_limits[j].soft_limit_seconds);
            if (j != REDIS_CLIENT_LIMIT_NUM_CLASSES-1)
                buf = sdscatlen(buf," ",1);
        }
        addReplyBulkCString(c,"client-output-buffer-limit");
        addReplyBulkCString(c,buf);
        sdsfree(buf);
        matches++;
    }
    if (stringmatch(pattern,"unixsocketperm",0)) {
        char buf[32];
        snprintf(buf,sizeof(buf),"%o",server.unixsocketperm);
        addReplyBulkCString(c,"unixsocketperm");
        addReplyBulkCString(c,buf);
        matches++;
    }
    if (stringmatch(pattern,"slaveof",0)) {
        char buf[256];

        addReplyBulkCString(c,"slaveof");
        if (server.masterhost)
            snprintf(buf,sizeof(buf),"%s %d",
                server.masterhost, server.masterport);
        else
            buf[0] = '\0';
        addReplyBulkCString(c,buf);
        matches++;
    }
    if (stringmatch(pattern,"notify-keyspace-events",0)) {
        robj *flagsobj = createObject(REDIS_STRING,
            keyspaceEventsFlagsToString(server.notify_keyspace_events));

        addReplyBulkCString(c,"notify-keyspace-events");
        addReplyBulk(c,flagsobj);
        decrRefCount(flagsobj);
        matches++;
    }
    setDeferredMultiBulkLength(c,replylen,matches*2);
}

/*-----------------------------------------------------------------------------
 * CONFIG REWRITE implementation
 *----------------------------------------------------------------------------*/

/* IGNORE:
 *
 * rename-command
 * include
 *
 * Special handling:
 *
 * notify-keyspace-events
 * client-output-buffer-limit
 * save
 * appendonly
 * appendfsync
 * dir
 * maxmemory-policy
 * loglevel
 * unixsocketperm
 * slaveof
 *
 * Type of config directives:
 *
 * CUSTOM
 * VERBATIM
 * YESNO
 * L
 * LL
 *
 */

/* We use the following dictionary type to store where a configuration
 * option is mentioned in the old configuration file, so it's
 * like "maxmemory" -> list of line numbers (first line is zero). */
unsigned int dictSdsHash(const void *key);
int dictSdsKeyCompare(void *privdata, const void *key1, const void *key2);
void dictSdsDestructor(void *privdata, void *val);
void dictListDestructor(void *privdata, void *val);

dictType optionToLineDictType = {
    dictSdsHash,                /* hash function */
    NULL,                       /* key dup */
    NULL,                       /* val dup */
    dictSdsKeyCompare,          /* key compare */
    dictSdsDestructor,          /* key destructor */
    dictListDestructor          /* val destructor */
};

/* The config rewrite state. */
struct rewriteConfigState {
    dict *option_to_line; /* Option -> list of config file lines map */
    int numlines;         /* Number of lines in current config */
    sds *lines;           /* Current lines as an array of sds strings */
    int has_tail;         /* True if we already added directives that were
                             not present in the original config file. */
};

/* Append the new line to the current configuration state. */
void rewriteConfigAppendLine(struct rewriteConfigState *state, sds line) {
    state->lines = zrealloc(state->lines, sizeof(char*) * (state->numlines+1));
    state->lines[state->numlines++] = line;
}

/* Populate the option -> list of line numbers map. */
void rewriteConfigAddLineNumberToOption(struct rewriteConfigState *state, sds option, int linenum) {
    list *l = dictFetchValue(state->option_to_line,option);

    if (l == NULL) {
        l = listCreate();
        dictAdd(state->option_to_line,sdsdup(option),l);
    }
    listAddNodeTail(l,(void*)(long)linenum);
}

/* Read the old file, split it into lines to populate a newly created
 * config rewrite state, and return it to the caller.
 *
 * If it is impossible to read the old file, NULL is returned.
 * If the old file does not exist at all, an empty state is returned. */
struct rewriteConfigState *rewriteConfigReadOldFile(char *path) {
    FILE *fp = fopen(path,"r");
    struct rewriteConfigState *state = zmalloc(sizeof(*state));
    char buf[REDIS_CONFIGLINE_MAX+1];
    int linenum = -1;

    if (fp == NULL && errno != ENOENT) return NULL;

    state->option_to_line = dictCreate(&optionToLineDictType,NULL);
    state->numlines = 0;
    state->lines = NULL;
    state->has_tail = 0;
    if (fp == NULL) return state;

    /* Read the old file line by line, populate the state. */
    while(fgets(buf,REDIS_CONFIGLINE_MAX+1,fp) != NULL) {
        int argc;
        sds *argv;
        sds line = sdstrim(sdsnew(buf),"\r\n\t ");

        linenum++; /* Zero based, so we init at -1 */

        /* Handle comments and empty lines. */
        if (line[0] == '#' || line[0] == '\0') {
            rewriteConfigAppendLine(state,line);
            continue;
        }

        /* Not a comment, split into arguments. */
        argv = sdssplitargs(line,&argc);
        if (argv == NULL) {
            /* Apparently the line is unparsable for some reason, for
             * instance it may have unbalanced quotes. Load it as a
             * comment. */
            sds aux = sdsnew("# ??? ");
            aux = sdscatsds(aux,line);
            sdsfree(line);
            rewriteConfigAppendLine(state,aux);
            continue;
        }

        sdstolower(argv[0]); /* We only want lowercase config directives. */

        /* Now we populate the state according to the content of this line.
         * Append the line and populate the option -> line numbers map. */
        rewriteConfigAppendLine(state,line);
        rewriteConfigAddLineNumberToOption(state,argv[0],linenum);

        sdsfreesplitres(argv,argc);
    }
    fclose(fp);
    return state;
}

/* Rewrite the specified configuration option with the new "line".
 * It progressively uses lines of the file that were already used for the same
 * configuraiton option in the old version of the file, removing that line from
 * the map of options -> line numbers.
 *
 * If there are lines associated with a given configuration option and
 * "force" is non-zero, the line is appended to the configuration file.
 * Usually "force" is true when an option has not its default value, so it
 * must be rewritten even if not present previously.
 * 
 * The first time a line is appended into a configuration file, a comment
 * is added to show that starting from that point the config file was generated
 * by CONFIG REWRITE.
 *
 * "line" is either used, or freed, so the caller does not need to free it
 * in any way. */
void rewriteConfigRewriteLine(struct rewriteConfigState *state, char *option, sds line, int force) {
    sds o = sdsnew(option);
    list *l = dictFetchValue(state->option_to_line,o);

    if (!l && !force) {
        /* Option not used previously, and we are not forced to use it. */
        sdsfree(line);
        sdsfree(o);
        return;
    }

    if (l) {
        listNode *ln = listFirst(l);
        int linenum = (long) ln->value;

        /* There are still lines in the old configuration file we can reuse
         * for this option. Replace the line with the new one. */
        listDelNode(l,ln);
        if (listLength(l) == 0) dictDelete(state->option_to_line,o);
        sdsfree(state->lines[linenum]);
        state->lines[linenum] = line;
    } else {
        /* Append a new line. */
        if (!state->has_tail) {
            rewriteConfigAppendLine(state,
                sdsnew("# Generated by CONFIG REWRITE"));
            state->has_tail = 1;
        }
        rewriteConfigAppendLine(state,line);
    }
    sdsfree(o);
}

/* Rewrite a simple "option-name <bytes>" configuration option. */
void rewriteConfigBytesOption(struct rewriteConfigState *state, char *option, long long value, long long defvalue) {
    int force = value != defvalue;
    /* TODO: check if we can write it using MB, GB, or other suffixes. */
    sds line = sdscatprintf(sdsempty(),"%s %lld",option,value);

    rewriteConfigRewriteLine(state,option,line,force);
}

/* Rewrite a yes/no option. */
void rewriteConfigYesNoOption(struct rewriteConfigState *state, char *option, int value, int defvalue) {
    int force = value != defvalue;
    sds line = sdscatprintf(sdsempty(),"%s %s",option,
        value ? "yes" : "no");

    rewriteConfigRewriteLine(state,option,line,force);
}

/* Rewrite a string option. */
void rewriteConfigStringOption(struct rewriteConfigState *state, char *option, char *value, char *defvalue) {
    int force = 1;
    sds line;

    /* String options set to NULL need to be not present at all in the
     * configuration file to be set to NULL again at the next reboot. */
    if (value == NULL) return;

    /* Compare the strings as sds strings to have a binary safe comparison. */
    if (defvalue && strcmp(value,defvalue) == 0) force = 0;

    line = sdsnew(option);
    line = sdscatlen(line, " ", 1);
    line = sdscatrepr(line, value, strlen(value));

    rewriteConfigRewriteLine(state,option,line,force);
}

/* Rewrite a numerical (long long range) option. */
void rewriteConfigNumericalOption(struct rewriteConfigState *state, char *option, long long value, long long defvalue) {
    int force = value != defvalue;
    sds line = sdscatprintf(sdsempty(),"%s %lld",option,value);

    rewriteConfigRewriteLine(state,option,line,force);
}

/* Rewrite a octal option. */
void rewriteConfigOctalOption(struct rewriteConfigState *state, char *option, int value, int defvalue) {
    int force = value != defvalue;
    sds line = sdscatprintf(sdsempty(),"%s %o",option,value);

    rewriteConfigRewriteLine(state,option,line,force);
}

/* Rewrite an enumeration option, after the "value" every enum/value pair
 * is specified, terminated by NULL. After NULL the default value is
 * specified. See how the function is used for more information. */
void rewriteConfigEnumOption(struct rewriteConfigState *state, char *option, int value, ...) {
    va_list ap;
    char *enum_name, *matching_name;
    int enum_val, def_val, force;
    sds line;
    
    va_start(ap, value);
    while(1) {
        enum_name = va_arg(ap,char*);
        enum_val = va_arg(ap,int);
        if (enum_name == NULL) {
            def_val = enum_val;
            break;
        }
        if (value == enum_val) matching_name = enum_name;
    }
    va_end(ap);
    
    force = value != def_val;
    line = sdscatprintf(sdsempty(),"%s %s",option,matching_name);
    rewriteConfigRewriteLine(state,option,line,force);
}

/* Rewrite the syslog-fability option. */
void rewriteConfigSyslogfacilityOption(struct rewriteConfigState *state) {
    int value = server.syslog_facility, j;
    int force = value != LOG_LOCAL0;
    char *name, *option = "syslog-facility";
    sds line;

    for (j = 0; validSyslogFacilities[j].name; j++) {
        if (validSyslogFacilities[j].value == value) {
            name = (char*) validSyslogFacilities[j].name;
            break;
        }
    }
    line = sdscatprintf(sdsempty(),"%s %s",option,name);
    rewriteConfigRewriteLine(state,option,line,force);
}

/* Rewrite the save option. */
void rewriteConfigSaveOption(struct rewriteConfigState *state) {
    int j;
    sds line;

    /* Note that if there are no save parameters at all, all the current
     * config line with "save" will be detected as orphaned and deleted,
     * resulting into no RDB persistence as expected. */
    for (j = 0; j < server.saveparamslen; j++) {
        line = sdscatprintf(sdsempty(),"save %ld %d",
            server.saveparams[j].seconds, server.saveparams[j].changes);
        rewriteConfigRewriteLine(state,"save",line,1);
    }
}

/* Rewrite the dir option, always using absolute paths.*/
void rewriteConfigDirOption(struct rewriteConfigState *state) {
    char cwd[1024];

    if (getcwd(cwd,sizeof(cwd)) == NULL) return; /* no rewrite on error. */
    rewriteConfigStringOption(state,"dir",cwd,NULL);
}

/* Rewrite the slaveof option. */
void rewriteConfigSlaveofOption(struct rewriteConfigState *state) {
    char *option = "slaveof";
    sds line;

    /* If this is a master, we want all the slaveof config options
     * in the file to be removed. */
    if (server.masterhost == NULL) return;
    line = sdscatprintf(sdsempty(),"%s %s %d", option,
        server.masterhost, server.masterport);
    rewriteConfigRewriteLine(state,option,line,1);
}

/* Rewrite the appendonly option. */
void rewriteConfigAppendonlyOption(struct rewriteConfigState *state) {
    int force = server.aof_state != REDIS_AOF_OFF;
    char *option = "appendonly";
    sds line;
    
    line = sdscatprintf(sdsempty(),"%s %s", option,
        (server.aof_state == REDIS_AOF_OFF) ? "no" : "yes");
    rewriteConfigRewriteLine(state,option,line,force);
}

/* Rewrite the notify-keyspace-events option. */
void rewriteConfigNotifykeyspaceeventsOption(struct rewriteConfigState *state) {
    int force = server.notify_keyspace_events != 0;
    char *option = "notify-keyspace-events";
    sds line, flags;

    flags = keyspaceEventsFlagsToString(server.notify_keyspace_events);
    line = sdscatprintf(sdsempty(),"%s %s", option, flags);
    sdsfree(flags);
    rewriteConfigRewriteLine(state,option,line,force);
}

/* Rewrite the client-output-buffer-limit option. */
void rewriteConfigClientoutputbufferlimitOption(struct rewriteConfigState *state) {
    int j;
    char *option = "client-output-buffer-limit";

    for (j = 0; j < REDIS_CLIENT_LIMIT_NUM_CLASSES; j++) {
        int force = (server.client_obuf_limits[j].hard_limit_bytes !=
                    clientBufferLimitsDefaults[j].hard_limit_bytes) ||
                    (server.client_obuf_limits[j].soft_limit_bytes !=
                    clientBufferLimitsDefaults[j].soft_limit_bytes) ||
                    (server.client_obuf_limits[j].soft_limit_seconds !=
                    clientBufferLimitsDefaults[j].soft_limit_seconds);
        sds line;

        line = sdscatprintf(sdsempty(),"%s %s %llu %llu %ld",
                option,
                getClientLimitClassName(j),
                server.client_obuf_limits[j].hard_limit_bytes,
                server.client_obuf_limits[j].soft_limit_bytes,
                (long) server.client_obuf_limits[j].soft_limit_seconds);
        rewriteConfigRewriteLine(state,option,line,force);
    }
}

/* Glue together the configuration lines in the current configuration
 * rewrite state into a single string, stripping multiple empty lines. */
sds rewriteConfigGetContentFromState(struct rewriteConfigState *state) {
    sds content = sdsempty();
    int j, was_empty = 0;

    for (j = 0; j < state->numlines; j++) {
        /* Every cluster of empty lines is turned into a single empty line. */
        if (sdslen(state->lines[j]) == 0) {
            if (was_empty) continue;
            was_empty = 1;
        } else {
            was_empty = 0;
        }
        content = sdscatsds(content,state->lines[j]);
        content = sdscatlen(content,"\n",1);
    }
    return content;
}

/* Free the configuration rewrite state. */
void rewriteConfigReleaseState(struct rewriteConfigState *state) {
    sdsfreesplitres(state->lines,state->numlines);
    dictRelease(state->option_to_line);
    zfree(state);
}

/* At the end of the rewrite process the state contains the remaining
 * map between "option name" => "lines in the original config file".
 * Lines used by the rewrite process were removed by the function
 * rewriteConfigRewriteLine(), all the other lines are "orphaned" and
 * should be replaced by empty lines.
 *
 * This function does just this, iterating all the option names and
 * blanking all the lines still associated. */
void rewriteConfigRemoveOrphaned(struct rewriteConfigState *state) {
    dictIterator *di = dictGetIterator(state->option_to_line);
    dictEntry *de;

    while((de = dictNext(di)) != NULL) {
        list *l = dictGetVal(de);

        while(listLength(l)) {
            listNode *ln = listFirst(l);
            int linenum = (long) ln->value;

            sdsfree(state->lines[linenum]);
            state->lines[linenum] = sdsempty();
            listDelNode(l,ln);
        }
    }
    dictReleaseIterator(di);
}

/* This function overwrites the old configuration file with the new content.
 *
 * 1) The old file length is obtained.
 * 2) If the new content is smaller, padding is added.
 * 3) A single write(2) call is used to replace the content of the file.
 * 4) Later the file is truncated to the length of the new content.
 *
 * This way we are sure the file is left in a consistent state even if the
 * process is stopped between any of the four operations.
 *
 * The function returns 0 on success, otherwise -1 is returned and errno
 * set accordingly. */
int rewriteConfigOverwriteFile(char *configfile, sds content) {
    int retval = 0;
    int fd = open(configfile,O_RDWR|O_CREAT);
    int content_size = sdslen(content), padding = 0;
    struct stat sb;
    sds content_padded;

    /* 1) Open the old file (or create a new one if it does not
     *    exist), get the size. */
    if (fd == -1) return -1; /* errno set by open(). */
    if (fstat(fd,&sb) == -1) {
        close(fd);
        return -1; /* errno set by fstat(). */
    }

    /* 2) Pad the content at least match the old file size. */
    content_padded = sdsdup(content);
    if (content_size < sb.st_size) {
        /* If the old file was bigger, pad the content with
         * a newline plus as many "#" chars as required. */
        padding = sb.st_size - content_size;
        content_padded = sdsgrowzero(content_padded,sb.st_size);
        content_padded[content_size] = '\n';
        memset(content_padded+content_size+1,'#',padding-1);
    }

    /* 3) Write the new content using a single write(2). */
    if (write(fd,content_padded,strlen(content_padded)) == -1) {
        retval = -1;
        goto cleanup;
    }

    /* 4) Truncate the file to the right length if we used padding. */
    if (padding) {
        if (ftruncate(fd,content_size) == -1) {
            /* Non critical error... */
        }
    }

cleanup:
    sdsfree(content_padded);
    close(fd);
    return retval;
}

/* Rewrite the configuration file at "path".
 * If the configuration file already exists, we try at best to retain comments
 * and overall structure.
 *
 * Configuration parameters that are at their default value, unless already
 * explicitly included in the old configuration file, are not rewritten.
 *
 * On error -1 is returned and errno is set accordingly, otherwise 0. */
int rewriteConfig(char *path) {
    struct rewriteConfigState *state;
    sds newcontent;
    int retval;

    /* Step 1: read the old config into our rewrite state. */
    if ((state = rewriteConfigReadOldFile(path)) == NULL) return -1;

    /* Step 2: rewrite every single option, replacing or appending it inside
     * the rewrite state. */

    /* TODO: Turn every default into a define, use it also in
     * initServerConfig(). */
    rewriteConfigYesNoOption(state,"daemonize",server.daemonize,0);
    rewriteConfigStringOption(state,"pidfile",server.pidfile,REDIS_DEFAULT_PID_FILE);
    rewriteConfigNumericalOption(state,"port",server.port,REDIS_SERVERPORT);
    rewriteConfigStringOption(state,"bindaddr",server.bindaddr,NULL);
    rewriteConfigStringOption(state,"unixsocket",server.unixsocket,NULL);
    rewriteConfigOctalOption(state,"unixsocketperm",server.unixsocketperm,0);
    rewriteConfigNumericalOption(state,"timeout",server.maxidletime,0);
    rewriteConfigNumericalOption(state,"tcp-keepalive",server.tcpkeepalive,0);
    rewriteConfigEnumOption(state,"loglevel",server.verbosity,
        "debug", REDIS_DEBUG,
        "verbose", REDIS_VERBOSE,
        "notice", REDIS_NOTICE,
        "warning", REDIS_WARNING,
        NULL, REDIS_NOTICE);
    rewriteConfigStringOption(state,"logfile",server.logfile,"stdout");
    rewriteConfigYesNoOption(state,"syslog-enabled",server.syslog_enabled,0);
    rewriteConfigStringOption(state,"syslog-ident",server.syslog_ident,REDIS_DEFAULT_SYSLOG_IDENT);
    rewriteConfigSyslogfacilityOption(state);
    rewriteConfigSaveOption(state);
    rewriteConfigNumericalOption(state,"databases",server.dbnum,REDIS_DEFAULT_DBNUM);
    rewriteConfigYesNoOption(state,"stop-writes-on-bgsave-error",server.stop_writes_on_bgsave_err,1);
    rewriteConfigYesNoOption(state,"rdbcompression",server.rdb_compression,1);
    rewriteConfigYesNoOption(state,"rdbchecksum",server.rdb_checksum,1);
    rewriteConfigStringOption(state,"dbfilename",server.rdb_filename,"dump.rdb");
    rewriteConfigDirOption(state);
    rewriteConfigSlaveofOption(state);
    rewriteConfigStringOption(state,"masterauth",server.masterauth,NULL);
    rewriteConfigYesNoOption(state,"slave-serve-stale-data",server.repl_serve_stale_data,1);
    rewriteConfigYesNoOption(state,"slave-read-only",server.repl_slave_ro,1);
    rewriteConfigNumericalOption(state,"repl-ping-slave-period",server.repl_ping_slave_period,REDIS_REPL_PING_SLAVE_PERIOD);
    rewriteConfigNumericalOption(state,"repl-timeout",server.repl_timeout,REDIS_REPL_TIMEOUT);
    rewriteConfigNumericalOption(state,"repl-backlog-size",server.repl_backlog_size,REDIS_DEFAULT_REPL_BACKLOG_SIZE);
    rewriteConfigBytesOption(state,"repl-backlog-ttl",server.repl_backlog_time_limit,REDIS_DEFAULT_REPL_BACKLOG_TIME_LIMIT);
    rewriteConfigNumericalOption(state,"slave-priority",server.slave_priority,REDIS_DEFAULT_SLAVE_PRIORITY);
    rewriteConfigStringOption(state,"requirepass",server.requirepass,NULL);
    rewriteConfigNumericalOption(state,"maxclients",server.maxclients,REDIS_MAX_CLIENTS);
    rewriteConfigBytesOption(state,"maxmemory",server.maxmemory,0);
    rewriteConfigEnumOption(state,"maxmemory-policy",server.maxmemory_policy,
        "volatile-lru", REDIS_MAXMEMORY_VOLATILE_LRU,
        "allkeys-lru", REDIS_MAXMEMORY_ALLKEYS_LRU,
        "volatile-random", REDIS_MAXMEMORY_VOLATILE_RANDOM,
        "allkeys-random", REDIS_MAXMEMORY_ALLKEYS_RANDOM,
        "volatile-ttl", REDIS_MAXMEMORY_VOLATILE_TTL,
        "noeviction", REDIS_MAXMEMORY_NO_EVICTION,
        NULL, REDIS_MAXMEMORY_VOLATILE_LRU);
    rewriteConfigNumericalOption(state,"maxmemory-samples",server.maxmemory_samples,3);
    rewriteConfigAppendonlyOption(state);
    rewriteConfigEnumOption(state,"appendfsync",server.aof_fsync,
        "eveysec", AOF_FSYNC_EVERYSEC,
        "always", AOF_FSYNC_ALWAYS,
        "no", AOF_FSYNC_NO,
        NULL, AOF_FSYNC_EVERYSEC);
    rewriteConfigYesNoOption(state,"no-appendfsync-on-rewrite",server.aof_no_fsync_on_rewrite,0);
    rewriteConfigNumericalOption(state,"auto-aof-rewrite-percentage",server.aof_rewrite_perc,REDIS_AOF_REWRITE_PERC);
    rewriteConfigBytesOption(state,"auto-aof-rewrite-min-size",server.aof_rewrite_min_size,REDIS_AOF_REWRITE_MIN_SIZE);
    rewriteConfigNumericalOption(state,"lua-time-limit",server.lua_time_limit,REDIS_LUA_TIME_LIMIT);
    rewriteConfigYesNoOption(state,"cluster-enabled",server.cluster_enabled,0);
    rewriteConfigStringOption(state,"cluster-config-file",server.cluster_configfile,REDIS_DEFAULT_CLUSTER_CONFIG_FILE);
    rewriteConfigNumericalOption(state,"cluster-node-timeout",server.cluster_node_timeout,REDIS_CLUSTER_DEFAULT_NODE_TIMEOUT);
    rewriteConfigNumericalOption(state,"slowlog-log-slower-than",server.slowlog_log_slower_than,REDIS_SLOWLOG_LOG_SLOWER_THAN);
    rewriteConfigNumericalOption(state,"slowlog-max-len",server.slowlog_max_len,REDIS_SLOWLOG_MAX_LEN);
    rewriteConfigNotifykeyspaceeventsOption(state);
    rewriteConfigNumericalOption(state,"hash-max-ziplist-entries",server.hash_max_ziplist_entries,REDIS_HASH_MAX_ZIPLIST_ENTRIES);
    rewriteConfigNumericalOption(state,"hash-max-ziplist-value",server.hash_max_ziplist_value,REDIS_HASH_MAX_ZIPLIST_VALUE);
    rewriteConfigNumericalOption(state,"list-max-ziplist-entries",server.list_max_ziplist_entries,REDIS_LIST_MAX_ZIPLIST_ENTRIES);
    rewriteConfigNumericalOption(state,"list-max-ziplist-value",server.list_max_ziplist_value,REDIS_LIST_MAX_ZIPLIST_VALUE);
    rewriteConfigNumericalOption(state,"set-max-intset-entries",server.set_max_intset_entries,REDIS_SET_MAX_INTSET_ENTRIES);
    rewriteConfigNumericalOption(state,"zset-max-ziplist-entries",server.zset_max_ziplist_entries,REDIS_ZSET_MAX_ZIPLIST_ENTRIES);
    rewriteConfigNumericalOption(state,"zset-max-ziplist-value",server.zset_max_ziplist_value,REDIS_ZSET_MAX_ZIPLIST_VALUE);
    rewriteConfigYesNoOption(state,"active-rehashing",server.activerehashing,1);
    rewriteConfigClientoutputbufferlimitOption(state);
    rewriteConfigNumericalOption(state,"hz",server.hz,REDIS_DEFAULT_HZ);
    rewriteConfigYesNoOption(state,"aof-rewrite-incremental-fsync",server.aof_rewrite_incremental_fsync,1);

    /* Step 3: remove all the orphaned lines in the old file, that is, lines
     * that were used by a config option and are no longer used, like in case
     * of multiple "save" options or duplicated options. */
    rewriteConfigRemoveOrphaned(state);

    /* Step 4: generate a new configuration file from the modified state
     * and write it into the original file. */
    newcontent = rewriteConfigGetContentFromState(state);
    retval = rewriteConfigOverwriteFile(server.configfile,newcontent);

    sdsfree(newcontent);
    rewriteConfigReleaseState(state);
    return retval;
}

/*-----------------------------------------------------------------------------
 * CONFIG command entry point
 *----------------------------------------------------------------------------*/

void configCommand(redisClient *c) {
    if (!strcasecmp(c->argv[1]->ptr,"set")) {
        if (c->argc != 4) goto badarity;
        configSetCommand(c);
    } else if (!strcasecmp(c->argv[1]->ptr,"get")) {
        if (c->argc != 3) goto badarity;
        configGetCommand(c);
    } else if (!strcasecmp(c->argv[1]->ptr,"resetstat")) {
        if (c->argc != 2) goto badarity;
        server.stat_keyspace_hits = 0;
        server.stat_keyspace_misses = 0;
        server.stat_numcommands = 0;
        server.stat_numconnections = 0;
        server.stat_expiredkeys = 0;
        server.stat_rejected_conn = 0;
        server.stat_fork_time = 0;
        server.aof_delayed_fsync = 0;
        resetCommandTableStats();
        addReply(c,shared.ok);
    } else if (!strcasecmp(c->argv[1]->ptr,"rewrite")) {
        if (c->argc != 2) goto badarity;
        if (server.configfile == NULL) {
            addReplyError(c,"The server is running without a config file");
            return;
        }
        if (rewriteConfig(server.configfile) == -1) {
            addReplyErrorFormat(c,"Rewriting config file: %s", strerror(errno));
        } else {
            addReply(c,shared.ok);
        }
    } else {
        addReplyError(c,
            "CONFIG subcommand must be one of GET, SET, RESETSTAT");
    }
    return;

badarity:
    addReplyErrorFormat(c,"Wrong number of arguments for CONFIG %s",
        (char*) c->argv[1]->ptr);
}