Function rewriteConfig

app/redis-6.2.6/src/config.c:1677–1722

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. * The force_all flag overrides this behavior and forces everything to be * written. This is current

 *
 * On error -1 is returned and errno is set accordingly, otherwise 0. */
int rewriteConfig(char *path, int force_all) {
    struct rewriteConfigState *state;
    sds newcontent;
    int retval;

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

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

    /* Iterate the configs that are standard */
    for (standardConfig *config = configs; config->name != NULL; config++) {
        config->interface.rewrite(config->data, config->name, state);
    }

    rewriteConfigBindOption(state);
    rewriteConfigOctalOption(state,"unixsocketperm",server.unixsocketperm,CONFIG_DEFAULT_UNIX_SOCKET_PERM);
    rewriteConfigStringOption(state,"logfile",server.logfile,CONFIG_DEFAULT_LOGFILE);
    rewriteConfigSaveOption(state);
    rewriteConfigUserOption(state);
    rewriteConfigDirOption(state);
    rewriteConfigSlaveofOption(state,"replicaof");
    rewriteConfigStringOption(state,"cluster-config-file",server.cluster_configfile,CONFIG_DEFAULT_CLUSTER_CONFIG_FILE);
    rewriteConfigNotifykeyspaceeventsOption(state);
    rewriteConfigClientoutputbufferlimitOption(state);
    rewriteConfigOOMScoreAdjValuesOption(state);

    /* Rewrite Sentinel config if in Sentinel mode. */
    if (server.sentinel_mode) rewriteConfigSentinelOption(state);

    /* 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;
}

/*-----------------------------------------------------------------------------
 * Configs that fit one of the major types and require no special handling