/*
 * Copyright (c) 2015, 2016 Nicira, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <config.h>

#include <ctype.h>
#include <errno.h>
#include <float.h>
#include <getopt.h>
#include <inttypes.h>
#include <signal.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "command-line.h"
#include "compiler.h"
#include "db-ctl-base.h"
#include "dirs.h"
#include "fatal-signal.h"
#include "openvswitch/dynamic-string.h"
#include "openvswitch/json.h"
#include "openvswitch/shash.h"
#include "openvswitch/vlog.h"
#include "ovn/lib/ovn-sb-idl.h"
#include "ovn/lib/ovn-util.h"
#include "ovsdb-data.h"
#include "ovsdb-idl.h"
#include "poll-loop.h"
#include "process.h"
#include "sset.h"
#include "stream-ssl.h"
#include "stream.h"
#include "table.h"
#include "timeval.h"
#include "util.h"

VLOG_DEFINE_THIS_MODULE(sbctl);

struct sbctl_context;

/* --db: The database server to contact. */
static const char *db;

/* --oneline: Write each command's output as a single line? */
static bool oneline;

/* --dry-run: Do not commit any changes. */
static bool dry_run;

/* --timeout: Time to wait for a connection to 'db'. */
static int timeout;

/* Format for table output. */
static struct table_style table_style = TABLE_STYLE_DEFAULT;

/* The IDL we're using and the current transaction, if any.
 * This is for use by sbctl_exit() only, to allow it to clean up.
 * Other code should use its context arguments. */
static struct ovsdb_idl *the_idl;
static struct ovsdb_idl_txn *the_idl_txn;
OVS_NO_RETURN static void sbctl_exit(int status);

static void sbctl_cmd_init(void);
OVS_NO_RETURN static void usage(void);
static void parse_options(int argc, char *argv[], struct shash *local_options);
static void run_prerequisites(struct ctl_command[], size_t n_commands,
                              struct ovsdb_idl *);
static bool do_sbctl(const char *args, struct ctl_command *, size_t n,
                     struct ovsdb_idl *);

int
main(int argc, char *argv[])
{
    struct ovsdb_idl *idl;
    struct ctl_command *commands;
    struct shash local_options;
    unsigned int seqno;
    size_t n_commands;
    char *args;

    set_program_name(argv[0]);
    fatal_ignore_sigpipe();
    vlog_set_levels(NULL, VLF_CONSOLE, VLL_WARN);
    vlog_set_levels_from_string_assert("reconnect:warn");
    sbrec_init();

    sbctl_cmd_init();

    /* Log our arguments.  This is often valuable for debugging systems. */
    args = process_escape_args(argv);
    VLOG(ctl_might_write_to_db(argv) ? VLL_INFO : VLL_DBG, "Called as %s", args);

    /* Parse command line. */
    shash_init(&local_options);
    parse_options(argc, argv, &local_options);
    commands = ctl_parse_commands(argc - optind, argv + optind, &local_options,
                                  &n_commands);

    if (timeout) {
        time_alarm(timeout);
    }

    /* Initialize IDL. */
    idl = the_idl = ovsdb_idl_create(db, &sbrec_idl_class, false, false);
    run_prerequisites(commands, n_commands, idl);

    /* Execute the commands.
     *
     * 'seqno' is the database sequence number for which we last tried to
     * execute our transaction.  There's no point in trying to commit more than
     * once for any given sequence number, because if the transaction fails
     * it's because the database changed and we need to obtain an up-to-date
     * view of the database before we try the transaction again. */
    seqno = ovsdb_idl_get_seqno(idl);
    for (;;) {
        ovsdb_idl_run(idl);
        if (!ovsdb_idl_is_alive(idl)) {
            int retval = ovsdb_idl_get_last_error(idl);
            ctl_fatal("%s: database connection failed (%s)",
                        db, ovs_retval_to_string(retval));
        }

        if (seqno != ovsdb_idl_get_seqno(idl)) {
            seqno = ovsdb_idl_get_seqno(idl);
            if (do_sbctl(args, commands, n_commands, idl)) {
                free(args);
                exit(EXIT_SUCCESS);
            }
        }

        if (seqno == ovsdb_idl_get_seqno(idl)) {
            ovsdb_idl_wait(idl);
            poll_block();
        }
    }
}

static void
parse_options(int argc, char *argv[], struct shash *local_options)
{
    enum {
        OPT_DB = UCHAR_MAX + 1,
        OPT_ONELINE,
        OPT_NO_SYSLOG,
        OPT_DRY_RUN,
        OPT_LOCAL,
        OPT_COMMANDS,
        OPT_OPTIONS,
        VLOG_OPTION_ENUMS,
        TABLE_OPTION_ENUMS
    };
    static const struct option global_long_options[] = {
        {"db", required_argument, NULL, OPT_DB},
        {"no-syslog", no_argument, NULL, OPT_NO_SYSLOG},
        {"dry-run", no_argument, NULL, OPT_DRY_RUN},
        {"oneline", no_argument, NULL, OPT_ONELINE},
        {"timeout", required_argument, NULL, 't'},
        {"help", no_argument, NULL, 'h'},
        {"commands", no_argument, NULL, OPT_COMMANDS},
        {"options", no_argument, NULL, OPT_OPTIONS},
        {"version", no_argument, NULL, 'V'},
        VLOG_LONG_OPTIONS,
        STREAM_SSL_LONG_OPTIONS,
        TABLE_LONG_OPTIONS,
        {NULL, 0, NULL, 0},
    };
    const int n_global_long_options = ARRAY_SIZE(global_long_options) - 1;
    char *tmp, *short_options;

    struct option *options;
    size_t allocated_options;
    size_t n_options;
    size_t i;

    tmp = ovs_cmdl_long_options_to_short_options(global_long_options);
    short_options = xasprintf("+%s", tmp);
    free(tmp);

    /* We want to parse both global and command-specific options here, but
     * getopt_long() isn't too convenient for the job.  We copy our global
     * options into a dynamic array, then append all of the command-specific
     * options. */
    options = xmemdup(global_long_options, sizeof global_long_options);
    allocated_options = ARRAY_SIZE(global_long_options);
    n_options = n_global_long_options;
    ctl_add_cmd_options(&options, &n_options, &allocated_options, OPT_LOCAL);
    table_style.format = TF_LIST;

    for (;;) {
        int idx;
        int c;

        c = getopt_long(argc, argv, short_options, options, &idx);
        if (c == -1) {
            break;
        }

        switch (c) {
        case OPT_DB:
            db = optarg;
            break;

        case OPT_ONELINE:
            oneline = true;
            break;

        case OPT_NO_SYSLOG:
            vlog_set_levels(&this_module, VLF_SYSLOG, VLL_WARN);
            break;

        case OPT_DRY_RUN:
            dry_run = true;
            break;

        case OPT_LOCAL:
            if (shash_find(local_options, options[idx].name)) {
                ctl_fatal("'%s' option specified multiple times",
                            options[idx].name);
            }
            shash_add_nocopy(local_options,
                             xasprintf("--%s", options[idx].name),
                             nullable_xstrdup(optarg));
            break;

        case 'h':
            usage();

        case OPT_COMMANDS:
            ctl_print_commands();

        case OPT_OPTIONS:
            ctl_print_options(global_long_options);

        case 'V':
            ovs_print_version(0, 0);
            printf("DB Schema %s\n", sbrec_get_db_version());
            exit(EXIT_SUCCESS);

        case 't':
            timeout = strtoul(optarg, NULL, 10);
            if (timeout < 0) {
                ctl_fatal("value %s on -t or --timeout is invalid", optarg);
            }
            break;

        VLOG_OPTION_HANDLERS
        TABLE_OPTION_HANDLERS(&table_style)
        STREAM_SSL_OPTION_HANDLERS

        case '?':
            exit(EXIT_FAILURE);

        default:
            abort();
        }
    }
    free(short_options);

    if (!db) {
        db = default_sb_db();
    }

    for (i = n_global_long_options; options[i].name; i++) {
        free(CONST_CAST(char *, options[i].name));
    }
    free(options);
}

static void
usage(void)
{
    printf("\
%s: OVN southbound DB management utility\n\
\n\
For debugging and testing only, not for use in production.\n\
\n\
usage: %s [OPTIONS] COMMAND [ARG...]\n\
\n\
General commands:\n\
  show                        print overview of database contents\n\
\n\
Chassis commands:\n\
  chassis-add CHASSIS ENCAP-TYPE ENCAP-IP  create a new chassis named\n\
                                           CHASSIS with ENCAP-TYPE tunnels\n\
                                           and ENCAP-IP\n\
  chassis-del CHASSIS         delete CHASSIS and all of its encaps\n\
                              and gateway_ports\n\
\n\
Port binding commands:\n\
  lsp-bind PORT CHASSIS       bind logical port PORT to CHASSIS\n\
  lsp-unbind PORT             reset the port binding of logical port PORT\n\
\n\
Logical flow commands:\n\
  lflow-list [DATAPATH]       List logical flows for all or a single datapath\n\
  dump-flows [DATAPATH]       Alias for lflow-list\n\
\n\
%s\
\n\
Options:\n\
  --db=DATABASE               connect to DATABASE\n\
                              (default: %s)\n\
  -t, --timeout=SECS          wait at most SECS seconds\n\
  --dry-run                   do not commit changes to database\n\
  --oneline                   print exactly one line of output per command\n",
           program_name, program_name, ctl_get_db_cmd_usage(),
           default_sb_db());
    vlog_usage();
    printf("\
  --no-syslog             equivalent to --verbose=sbctl:syslog:warn\n");
    printf("\n\
Other options:\n\
  -h, --help                  display this help message\n\
  -V, --version               display version information\n");
    stream_usage("database", true, true, false);
    exit(EXIT_SUCCESS);
}


/* ovs-sbctl specific context.  Inherits the 'struct ctl_context' as base. */
struct sbctl_context {
    struct ctl_context base;

    /* A cache of the contents of the database.
     *
     * A command that needs to use any of this information must first call
     * sbctl_context_populate_cache().  A command that changes anything that
     * could invalidate the cache must either call
     * sbctl_context_invalidate_cache() or manually update the cache to
     * maintain its correctness. */
    bool cache_valid;
    /* Maps from chassis name to struct sbctl_chassis. */
    struct shash chassis;
    /* Maps from lport name to struct sbctl_port_binding. */
    struct shash port_bindings;
};

/* Casts 'base' into 'struct sbctl_context'. */
static struct sbctl_context *
sbctl_context_cast(struct ctl_context *base)
{
    return CONTAINER_OF(base, struct sbctl_context, base);
}

struct sbctl_chassis {
    const struct sbrec_chassis *ch_cfg;
};

struct sbctl_port_binding {
    const struct sbrec_port_binding *bd_cfg;
};

static void
sbctl_context_invalidate_cache(struct ctl_context *ctx)
{
    struct sbctl_context *sbctl_ctx = sbctl_context_cast(ctx);

    if (!sbctl_ctx->cache_valid) {
        return;
    }
    sbctl_ctx->cache_valid = false;
    shash_destroy_free_data(&sbctl_ctx->chassis);
    shash_destroy_free_data(&sbctl_ctx->port_bindings);
}

static void
sbctl_context_populate_cache(struct ctl_context *ctx)
{
    struct sbctl_context *sbctl_ctx = sbctl_context_cast(ctx);
    const struct sbrec_chassis *chassis_rec;
    const struct sbrec_port_binding *port_binding_rec;
    struct sset chassis, port_bindings;

    if (sbctl_ctx->cache_valid) {
        /* Cache is already populated. */
        return;
    }
    sbctl_ctx->cache_valid = true;
    shash_init(&sbctl_ctx->chassis);
    shash_init(&sbctl_ctx->port_bindings);
    sset_init(&chassis);
    SBREC_CHASSIS_FOR_EACH(chassis_rec, ctx->idl) {
        struct sbctl_chassis *ch;

        if (!sset_add(&chassis, chassis_rec->name)) {
            VLOG_WARN("database contains duplicate chassis name (%s)",
                      chassis_rec->name);
            continue;
        }

        ch = xmalloc(sizeof *ch);
        ch->ch_cfg = chassis_rec;
        shash_add(&sbctl_ctx->chassis, chassis_rec->name, ch);
    }
    sset_destroy(&chassis);

    sset_init(&port_bindings);
    SBREC_PORT_BINDING_FOR_EACH(port_binding_rec, ctx->idl) {
        struct sbctl_port_binding *bd;

        if (!sset_add(&port_bindings, port_binding_rec->logical_port)) {
            VLOG_WARN("database contains duplicate port binding for logical "
                      "port (%s)",
                      port_binding_rec->logical_port);
            continue;
        }

        bd = xmalloc(sizeof *bd);
        bd->bd_cfg = port_binding_rec;
        shash_add(&sbctl_ctx->port_bindings, port_binding_rec->logical_port,
                  bd);
    }
    sset_destroy(&port_bindings);
}

static void
check_conflicts(struct sbctl_context *sbctl_ctx, const char *name,
                char *msg)
{
    if (shash_find(&sbctl_ctx->chassis, name)) {
        ctl_fatal("%s because a chassis named %s already exists",
                    msg, name);
    }
    free(msg);
}

static struct sbctl_chassis *
find_chassis(struct sbctl_context *sbctl_ctx, const char *name,
             bool must_exist)
{
    struct sbctl_chassis *sbctl_ch;

    ovs_assert(sbctl_ctx->cache_valid);

    sbctl_ch = shash_find_data(&sbctl_ctx->chassis, name);
    if (must_exist && !sbctl_ch) {
        ctl_fatal("no chassis named %s", name);
    }

    return sbctl_ch;
}

static struct sbctl_port_binding *
find_port_binding(struct sbctl_context *sbctl_ctx, const char *name,
                  bool must_exist)
{
    struct sbctl_port_binding *bd;

    ovs_assert(sbctl_ctx->cache_valid);

    bd = shash_find_data(&sbctl_ctx->port_bindings, name);
    if (must_exist && !bd) {
        ctl_fatal("no port named %s", name);
    }

    return bd;
}

static void
pre_get_info(struct ctl_context *ctx)
{
    ovsdb_idl_add_column(ctx->idl, &sbrec_chassis_col_name);
    ovsdb_idl_add_column(ctx->idl, &sbrec_chassis_col_encaps);

    ovsdb_idl_add_column(ctx->idl, &sbrec_encap_col_type);
    ovsdb_idl_add_column(ctx->idl, &sbrec_encap_col_ip);

    ovsdb_idl_add_column(ctx->idl, &sbrec_port_binding_col_logical_port);
    ovsdb_idl_add_column(ctx->idl, &sbrec_port_binding_col_chassis);

    ovsdb_idl_add_column(ctx->idl, &sbrec_logical_flow_col_logical_datapath);
    ovsdb_idl_add_column(ctx->idl, &sbrec_logical_flow_col_pipeline);
    ovsdb_idl_add_column(ctx->idl, &sbrec_logical_flow_col_actions);
    ovsdb_idl_add_column(ctx->idl, &sbrec_logical_flow_col_priority);
    ovsdb_idl_add_column(ctx->idl, &sbrec_logical_flow_col_table_id);
    ovsdb_idl_add_column(ctx->idl, &sbrec_logical_flow_col_match);
    ovsdb_idl_add_column(ctx->idl, &sbrec_logical_flow_col_external_ids);

    ovsdb_idl_add_column(ctx->idl, &sbrec_datapath_binding_col_external_ids);
}

static struct cmd_show_table cmd_show_tables[] = {
    {&sbrec_table_chassis,
     &sbrec_chassis_col_name,
     {&sbrec_chassis_col_hostname,
      &sbrec_chassis_col_encaps,
      NULL},
     {&sbrec_table_port_binding,
      &sbrec_port_binding_col_logical_port,
      &sbrec_port_binding_col_chassis}},

    {&sbrec_table_encap,
     &sbrec_encap_col_type,
     {&sbrec_encap_col_ip,
      &sbrec_encap_col_options,
      NULL},
     {NULL, NULL, NULL}},

    {NULL, NULL, {NULL, NULL, NULL}, {NULL, NULL, NULL}},
};

static void
sbctl_init(struct ctl_context *ctx OVS_UNUSED)
{
}

static void
cmd_chassis_add(struct ctl_context *ctx)
{
    struct sbctl_context *sbctl_ctx = sbctl_context_cast(ctx);
    bool may_exist = shash_find(&ctx->options, "--may-exist") != NULL;
    const char *ch_name, *encap_types, *encap_ip;

    ch_name = ctx->argv[1];
    encap_types = ctx->argv[2];
    encap_ip = ctx->argv[3];

    sbctl_context_populate_cache(ctx);
    if (may_exist) {
        struct sbctl_chassis *sbctl_ch;

        sbctl_ch = find_chassis(sbctl_ctx, ch_name, false);
        if (sbctl_ch) {
            return;
        }
    }
    check_conflicts(sbctl_ctx, ch_name,
                    xasprintf("cannot create a chassis named %s", ch_name));

    struct sset encap_set;
    sset_from_delimited_string(&encap_set, encap_types, ",");

    size_t n_encaps = sset_count(&encap_set);
    struct sbrec_encap **encaps = xmalloc(n_encaps * sizeof *encaps);
    const struct smap options = SMAP_CONST1(&options, "csum", "true");
    const char *encap_type;
    int i = 0;
    SSET_FOR_EACH (encap_type, &encap_set){
        encaps[i] = sbrec_encap_insert(ctx->txn);

        sbrec_encap_set_type(encaps[i], encap_type);
        sbrec_encap_set_ip(encaps[i], encap_ip);
        sbrec_encap_set_options(encaps[i], &options);
        i++;
    }
    sset_destroy(&encap_set);

    struct sbrec_chassis *ch = sbrec_chassis_insert(ctx->txn);
    sbrec_chassis_set_name(ch, ch_name);
    sbrec_chassis_set_encaps(ch, encaps, n_encaps);
    free(encaps);

    sbctl_context_invalidate_cache(ctx);
}

static void
cmd_chassis_del(struct ctl_context *ctx)
{
    struct sbctl_context *sbctl_ctx = sbctl_context_cast(ctx);
    bool must_exist = !shash_find(&ctx->options, "--if-exists");
    struct sbctl_chassis *sbctl_ch;

    sbctl_context_populate_cache(ctx);
    sbctl_ch = find_chassis(sbctl_ctx, ctx->argv[1], must_exist);
    if (sbctl_ch) {
        if (sbctl_ch->ch_cfg) {
            size_t i;

            for (i = 0; i < sbctl_ch->ch_cfg->n_encaps; i++) {
                sbrec_encap_delete(sbctl_ch->ch_cfg->encaps[i]);
            }
            sbrec_chassis_delete(sbctl_ch->ch_cfg);
        }
        shash_find_and_delete(&sbctl_ctx->chassis, ctx->argv[1]);
        free(sbctl_ch);
    }
}

static void
cmd_lsp_bind(struct ctl_context *ctx)
{
    struct sbctl_context *sbctl_ctx = sbctl_context_cast(ctx);
    bool may_exist = shash_find(&ctx->options, "--may-exist") != NULL;
    struct sbctl_chassis *sbctl_ch;
    struct sbctl_port_binding *sbctl_bd;
    char *lport_name, *ch_name;

    /* port_binding must exist, chassis must exist! */
    lport_name = ctx->argv[1];
    ch_name = ctx->argv[2];

    sbctl_context_populate_cache(ctx);
    sbctl_bd = find_port_binding(sbctl_ctx, lport_name, true);
    sbctl_ch = find_chassis(sbctl_ctx, ch_name, true);

    if (sbctl_bd->bd_cfg->chassis) {
        if (may_exist && sbctl_bd->bd_cfg->chassis == sbctl_ch->ch_cfg) {
            return;
        } else {
            ctl_fatal("lport (%s) has already been binded to chassis (%s)",
                      lport_name, sbctl_bd->bd_cfg->chassis->name);
        }
    }
    sbrec_port_binding_set_chassis(sbctl_bd->bd_cfg, sbctl_ch->ch_cfg);
    sbctl_context_invalidate_cache(ctx);
}

static void
cmd_lsp_unbind(struct ctl_context *ctx)
{
    struct sbctl_context *sbctl_ctx = sbctl_context_cast(ctx);
    bool must_exist = !shash_find(&ctx->options, "--if-exists");
    struct sbctl_port_binding *sbctl_bd;
    char *lport_name;

    lport_name = ctx->argv[1];
    sbctl_context_populate_cache(ctx);
    sbctl_bd = find_port_binding(sbctl_ctx, lport_name, must_exist);
    if (sbctl_bd) {
        sbrec_port_binding_set_chassis(sbctl_bd->bd_cfg, NULL);
    }
}

enum {
    PL_INGRESS,
    PL_EGRESS,
};

/* Help ensure we catch any future pipeline values */
static int
pipeline_encode(const char *pl)
{
    if (!strcmp(pl, "ingress")) {
        return PL_INGRESS;
    } else if (!strcmp(pl, "egress")) {
        return PL_EGRESS;
    }

    OVS_NOT_REACHED();
}

static int
lflow_cmp(const void *lf1_, const void *lf2_)
{
    const struct sbrec_logical_flow *const *lf1p = lf1_;
    const struct sbrec_logical_flow *const *lf2p = lf2_;
    const struct sbrec_logical_flow *lf1 = *lf1p;
    const struct sbrec_logical_flow *lf2 = *lf2p;

    int pl1 = pipeline_encode(lf1->pipeline);
    int pl2 = pipeline_encode(lf2->pipeline);

#define CMP(expr) \
    do { \
        int res; \
        res = (expr); \
        if (res) { \
            return res; \
        } \
    } while (0)

    CMP(uuid_compare_3way(&lf1->logical_datapath->header_.uuid,
                          &lf2->logical_datapath->header_.uuid));
    CMP(pl1 - pl2);
    CMP(lf1->table_id > lf2->table_id ? 1 :
            (lf1->table_id < lf2->table_id ? -1 : 0));
    CMP(lf1->priority > lf2->priority ? -1 :
            (lf1->priority < lf2->priority ? 1 : 0));
    CMP(strcmp(lf1->match, lf2->match));

#undef CMP

    return 0;
}

static void
cmd_lflow_list(struct ctl_context *ctx)
{
    const char *datapath = ctx->argc == 2 ? ctx->argv[1] : NULL;
    struct uuid datapath_uuid = { .parts = { 0, }};
    const struct sbrec_logical_flow **lflows;
    const struct sbrec_logical_flow *lflow;
    size_t n_flows = 0, n_capacity = 64;

    if (datapath && !uuid_from_string(&datapath_uuid, datapath)) {
        VLOG_ERR("Invalid format of datapath UUID");
        return;
    }

    lflows = xmalloc(sizeof *lflows * n_capacity);
    SBREC_LOGICAL_FLOW_FOR_EACH (lflow, ctx->idl) {
        if (n_flows == n_capacity) {
            lflows = x2nrealloc(lflows, &n_capacity, sizeof *lflows);
        }
        lflows[n_flows] = lflow;
        n_flows++;
    }

    qsort(lflows, n_flows, sizeof *lflows, lflow_cmp);

    const char *cur_pipeline = "";
    size_t i;
    for (i = 0; i < n_flows; i++) {
        lflow = lflows[i];
        if (datapath && !uuid_equals(&datapath_uuid,
                                     &lflow->logical_datapath->header_.uuid)) {
            continue;
        }
        if (strcmp(cur_pipeline, lflow->pipeline)) {
            printf("Datapath: \"%s\" ("UUID_FMT")  Pipeline: %s\n",
                   smap_get_def(&lflow->logical_datapath->external_ids,
                                "name", ""),
                   UUID_ARGS(&lflow->logical_datapath->header_.uuid),
                   lflow->pipeline);
            cur_pipeline = lflow->pipeline;
        }

        printf("  table=%-2" PRId64 "(%-19s), priority=%-5" PRId64
               ", match=(%s), action=(%s)\n",
               lflow->table_id,
               smap_get_def(&lflow->external_ids, "stage-name", ""),
               lflow->priority, lflow->match, lflow->actions);
    }

    free(lflows);
}


static const struct ctl_table_class tables[] = {
    {&sbrec_table_sb_global,
     {{&sbrec_table_sb_global, NULL, NULL},
      {NULL, NULL, NULL}}},

    {&sbrec_table_chassis,
     {{&sbrec_table_chassis, &sbrec_chassis_col_name, NULL},
      {NULL, NULL, NULL}}},

    {&sbrec_table_encap,
     {{NULL, NULL, NULL},
      {NULL, NULL, NULL}}},

    {&sbrec_table_logical_flow,
     {{&sbrec_table_logical_flow, NULL,
       &sbrec_logical_flow_col_logical_datapath},
      {NULL, NULL, NULL}}},

    {&sbrec_table_multicast_group,
     {{NULL, NULL, NULL},
      {NULL, NULL, NULL}}},

    {&sbrec_table_datapath_binding,
     {{NULL, NULL, NULL},
      {NULL, NULL, NULL}}},

    {&sbrec_table_port_binding,
     {{&sbrec_table_port_binding, &sbrec_port_binding_col_logical_port, NULL},
      {NULL, NULL, NULL}}},

    {&sbrec_table_mac_binding,
     {{&sbrec_table_mac_binding, &sbrec_mac_binding_col_logical_port, NULL},
      {NULL, NULL, NULL}}},

    {&sbrec_table_address_set,
     {{&sbrec_table_address_set, &sbrec_address_set_col_name, NULL},
      {NULL, NULL, NULL}}},

    {NULL, {{NULL, NULL, NULL}, {NULL, NULL, NULL}}}
};


static void
sbctl_context_init_command(struct sbctl_context *sbctl_ctx,
                           struct ctl_command *command)
{
    ctl_context_init_command(&sbctl_ctx->base, command);
}

static void
sbctl_context_init(struct sbctl_context *sbctl_ctx,
                   struct ctl_command *command, struct ovsdb_idl *idl,
                   struct ovsdb_idl_txn *txn,
                   struct ovsdb_symbol_table *symtab)
{
    ctl_context_init(&sbctl_ctx->base, command, idl, txn, symtab,
                     sbctl_context_invalidate_cache);
    sbctl_ctx->cache_valid = false;
}

static void
sbctl_context_done_command(struct sbctl_context *sbctl_ctx,
                           struct ctl_command *command)
{
    ctl_context_done_command(&sbctl_ctx->base, command);
}

static void
sbctl_context_done(struct sbctl_context *sbctl_ctx,
                   struct ctl_command *command)
{
    ctl_context_done(&sbctl_ctx->base, command);
}

static void
run_prerequisites(struct ctl_command *commands, size_t n_commands,
                  struct ovsdb_idl *idl)
{
    ovsdb_idl_add_table(idl, &sbrec_table_sb_global);

    for (struct ctl_command *c = commands; c < &commands[n_commands]; c++) {
        if (c->syntax->prerequisites) {
            struct sbctl_context sbctl_ctx;

            ds_init(&c->output);
            c->table = NULL;

            sbctl_context_init(&sbctl_ctx, c, idl, NULL, NULL);
            (c->syntax->prerequisites)(&sbctl_ctx.base);
            sbctl_context_done(&sbctl_ctx, c);

            ovs_assert(!c->output.string);
            ovs_assert(!c->table);
        }
    }
}

static bool
do_sbctl(const char *args, struct ctl_command *commands, size_t n_commands,
         struct ovsdb_idl *idl)
{
    struct ovsdb_idl_txn *txn;
    enum ovsdb_idl_txn_status status;
    struct ovsdb_symbol_table *symtab;
    struct sbctl_context sbctl_ctx;
    struct ctl_command *c;
    struct shash_node *node;
    char *error = NULL;

    txn = the_idl_txn = ovsdb_idl_txn_create(idl);
    if (dry_run) {
        ovsdb_idl_txn_set_dry_run(txn);
    }

    ovsdb_idl_txn_add_comment(txn, "ovs-sbctl: %s", args);

    const struct sbrec_sb_global *sb = sbrec_sb_global_first(idl);
    if (!sb) {
        /* XXX add verification that table is empty */
        sb = sbrec_sb_global_insert(txn);
    }

    symtab = ovsdb_symbol_table_create();
    for (c = commands; c < &commands[n_commands]; c++) {
        ds_init(&c->output);
        c->table = NULL;
    }
    sbctl_context_init(&sbctl_ctx, NULL, idl, txn, symtab);
    for (c = commands; c < &commands[n_commands]; c++) {
        sbctl_context_init_command(&sbctl_ctx, c);
        if (c->syntax->run) {
            (c->syntax->run)(&sbctl_ctx.base);
        }
        sbctl_context_done_command(&sbctl_ctx, c);

        if (sbctl_ctx.base.try_again) {
            sbctl_context_done(&sbctl_ctx, NULL);
            goto try_again;
        }
    }
    sbctl_context_done(&sbctl_ctx, NULL);

    SHASH_FOR_EACH (node, &symtab->sh) {
        struct ovsdb_symbol *symbol = node->data;
        if (!symbol->created) {
            ctl_fatal("row id \"%s\" is referenced but never created (e.g. "
                      "with \"-- --id=%s create ...\")",
                      node->name, node->name);
        }
        if (!symbol->strong_ref) {
            if (!symbol->weak_ref) {
                VLOG_WARN("row id \"%s\" was created but no reference to it "
                          "was inserted, so it will not actually appear in "
                          "the database", node->name);
            } else {
                VLOG_WARN("row id \"%s\" was created but only a weak "
                          "reference to it was inserted, so it will not "
                          "actually appear in the database", node->name);
            }
        }
    }

    status = ovsdb_idl_txn_commit_block(txn);
    if (status == TXN_UNCHANGED || status == TXN_SUCCESS) {
        for (c = commands; c < &commands[n_commands]; c++) {
            if (c->syntax->postprocess) {
                sbctl_context_init(&sbctl_ctx, c, idl, txn, symtab);
                (c->syntax->postprocess)(&sbctl_ctx.base);
                sbctl_context_done(&sbctl_ctx, c);
            }
        }
    }
    error = xstrdup(ovsdb_idl_txn_get_error(txn));

    switch (status) {
    case TXN_UNCOMMITTED:
    case TXN_INCOMPLETE:
        OVS_NOT_REACHED();

    case TXN_ABORTED:
        /* Should not happen--we never call ovsdb_idl_txn_abort(). */
        ctl_fatal("transaction aborted");

    case TXN_UNCHANGED:
    case TXN_SUCCESS:
        break;

    case TXN_TRY_AGAIN:
        goto try_again;

    case TXN_ERROR:
        ctl_fatal("transaction error: %s", error);

    case TXN_NOT_LOCKED:
        /* Should not happen--we never call ovsdb_idl_set_lock(). */
        ctl_fatal("database not locked");

    default:
        OVS_NOT_REACHED();
    }
    free(error);

    ovsdb_symbol_table_destroy(symtab);

    for (c = commands; c < &commands[n_commands]; c++) {
        struct ds *ds = &c->output;

        if (c->table) {
            table_print(c->table, &table_style);
        } else if (oneline) {
            size_t j;

            ds_chomp(ds, '\n');
            for (j = 0; j < ds->length; j++) {
                int ch = ds->string[j];
                switch (ch) {
                case '\n':
                    fputs("\\n", stdout);
                    break;

                case '\\':
                    fputs("\\\\", stdout);
                    break;

                default:
                    putchar(ch);
                }
            }
            putchar('\n');
        } else {
            fputs(ds_cstr(ds), stdout);
        }
        ds_destroy(&c->output);
        table_destroy(c->table);
        free(c->table);

        shash_destroy_free_data(&c->options);
    }
    free(commands);
    ovsdb_idl_txn_destroy(txn);
    ovsdb_idl_destroy(idl);

    return true;

try_again:
    /* Our transaction needs to be rerun, or a prerequisite was not met.  Free
     * resources and return so that the caller can try again. */
    if (txn) {
        ovsdb_idl_txn_abort(txn);
        ovsdb_idl_txn_destroy(txn);
        the_idl_txn = NULL;
    }
    ovsdb_symbol_table_destroy(symtab);
    for (c = commands; c < &commands[n_commands]; c++) {
        ds_destroy(&c->output);
        table_destroy(c->table);
        free(c->table);
    }
    free(error);
    return false;
}

/* Frees the current transaction and the underlying IDL and then calls
 * exit(status).
 *
 * Freeing the transaction and the IDL is not strictly necessary, but it makes
 * for a clean memory leak report from valgrind in the normal case.  That makes
 * it easier to notice real memory leaks. */
static void
sbctl_exit(int status)
{
    if (the_idl_txn) {
        ovsdb_idl_txn_abort(the_idl_txn);
        ovsdb_idl_txn_destroy(the_idl_txn);
    }
    ovsdb_idl_destroy(the_idl);
    exit(status);
}

static const struct ctl_command_syntax sbctl_commands[] = {
    { "init", 0, 0, "", NULL, sbctl_init, NULL, "", RW },

    /* Chassis commands. */
    {"chassis-add", 3, 3, "CHASSIS ENCAP-TYPE ENCAP-IP", pre_get_info,
     cmd_chassis_add, NULL, "--may-exist", RW},
    {"chassis-del", 1, 1, "CHASSIS", pre_get_info, cmd_chassis_del, NULL,
     "--if-exists", RW},

    /* Port binding commands. */
    {"lsp-bind", 2, 2, "PORT CHASSIS", pre_get_info, cmd_lsp_bind, NULL,
     "--may-exist", RW},
    {"lsp-unbind", 1, 1, "PORT", pre_get_info, cmd_lsp_unbind, NULL,
     "--if-exists", RW},

    /* Logical flow commands */
    {"lflow-list", 0, 1, "[DATAPATH]", pre_get_info, cmd_lflow_list, NULL,
     "", RO},
    {"dump-flows", 0, 1, "[DATAPATH]", pre_get_info, cmd_lflow_list, NULL,
     "", RO}, /* Friendly alias for lflow-list */

    /* SSL commands (To Be Added). */

    {NULL, 0, 0, NULL, NULL, NULL, NULL, NULL, RO},
};

/* Registers sbctl and common db commands. */
static void
sbctl_cmd_init(void)
{
    ctl_init(tables, cmd_show_tables, sbctl_exit);
    ctl_register_commands(sbctl_commands);
}
