/*      $OpenBSD: parser.c,v 1.4 2018/10/15 11:30:01 florian Exp $ */

/*
 * Copyright (c) 2004 Esben Norby <norby@openbsd.org>
 * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <netinet/in.h>
#include <err.h>
#include <errno.h>
#include <event.h>
#include <limits.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "iscsid.h"
#include "iscsictl.h"

enum token_type {
        NOTOKEN,
        ENDTOKEN,
        KEYWORD,
        ADDRESS,
        NAME,
        FLAG
};

struct token {
        enum token_type          type;
        const char              *keyword;
        int                      value;
        const struct token      *next;
};

static const struct token t_main[];
static const struct token t_show[];
static const struct token t_log[];
static const struct token t_discovery[];
static const struct token t_session[];
static const struct token t_vscsi[];

static const struct token t_main[] = {
        {KEYWORD,       "reload",       RELOAD,         NULL},
        {KEYWORD,       "discover",     DISCOVERY,      t_discovery},
        {KEYWORD,       "show",         SHOW_SUM,       t_show},
        {KEYWORD,       "log",          NONE,           t_log},
        {ENDTOKEN,      "",             NONE,           NULL}
};

static const struct token t_show[] = {
        {NOTOKEN,       "",             NONE,           NULL},
        {KEYWORD,       "summary",      SHOW_SUM,       NULL},
        {KEYWORD,       "session",      SHOW_SESS,      t_session},
        {KEYWORD,       "vscsi",        NONE,           t_vscsi},
        {ENDTOKEN,      "",             NONE,           NULL}
};

static const struct token t_log[] = {
        {KEYWORD,       "verbose",      LOG_VERBOSE,            NULL},
        {KEYWORD,       "brief",        LOG_BRIEF,              NULL},
        {ENDTOKEN,      "",             NONE,                   NULL}
};

static const struct token t_discovery[] = {
        {ADDRESS,       "",             NONE,                   NULL},
        {ENDTOKEN,      "",             NONE,                   NULL}
};

static const struct token t_session[] = {
        {NAME,          "",             NONE,                   NULL},
        {ENDTOKEN,      "",             NONE,                   NULL}
};

static const struct token t_vscsi[] = {
        {KEYWORD,       "stats",        SHOW_VSCSI_STATS,       NULL},
        {ENDTOKEN,      "",             NONE,                   NULL}
};

static struct parse_result      res;

struct parse_result *
parse(int argc, char *argv[])
{
        const struct token      *table = t_main;
        const struct token      *match;

        bzero(&res, sizeof(res));

        while (argc >= 0) {
                if ((match = match_token(argv[0], table)) == NULL) {
                        fprintf(stderr, "valid commands/args:\n");
                        show_valid_args(table);
                        return (NULL);
                }

                argc--;
                argv++;

                if (match->type == NOTOKEN || match->next == NULL)
                        break;

                table = match->next;
        }

        if (argc > 0) {
                fprintf(stderr, "superfluous argument: %s\n", argv[0]);
                return (NULL);
        }

        return (&res);
}

const struct token *
match_token(const char *word, const struct token *table)
{
        u_int                    i, match;
        const struct token      *t = NULL;

        match = 0;

        for (i = 0; table[i].type != ENDTOKEN; i++) {
                switch (table[i].type) {
                case NOTOKEN:
                        if (word == NULL || strlen(word) == 0) {
                                match++;
                                t = &table[i];
                        }
                        break;
                case KEYWORD:
                        if (word != NULL && strncmp(word, table[i].keyword,
                            strlen(word)) == 0) {
                                match++;
                                t = &table[i];
                                if (t->value)
                                        res.action = t->value;
                        }
                        break;
                case FLAG:
                        if (word != NULL && strncmp(word, table[i].keyword,
                            strlen(word)) == 0) {
                                match++;
                                t = &table[i];
                                res.flags |= t->value;
                        }
                        break;
                case ADDRESS:
                        if (!parse_addr(word, &res.addr)) {
                                match++;
                                t = &table[i];
                                if (t->value)
                                        res.action = t->value;
                        }
                        break;
                case NAME:
                        if (word != NULL && strlen(word) > 0) {
                                if (strlcpy(res.name, word, sizeof(res.name)) >=
                                    sizeof(res.name))
                                        errx(1, "name too long");
                                match++;
                                t = &table[i];
                        }
                        break;
                case ENDTOKEN:
                        break;
                }
        }

        if (match != 1) {
                if (word == NULL)
                        fprintf(stderr, "missing argument:\n");
                else if (match > 1)
                        fprintf(stderr, "ambiguous argument: %s\n", word);
                else if (match < 1)
                        fprintf(stderr, "unknown argument: %s\n", word);
                return (NULL);
        }

        return (t);
}

void
show_valid_args(const struct token *table)
{
        int     i;

        for (i = 0; table[i].type != ENDTOKEN; i++) {
                switch (table[i].type) {
                case NOTOKEN:
                        fprintf(stderr, "  <cr>\n");
                        break;
                case KEYWORD:
                case FLAG:
                        fprintf(stderr, "  %s\n", table[i].keyword);
                        break;
                case ADDRESS:
                        fprintf(stderr, "  <address>\n");
                        break;
                case NAME:
                        fprintf(stderr, "  <name>\n");
                        break;
                case ENDTOKEN:
                        break;
                }
        }
}

int
parse_addr(const char *word, struct sockaddr_storage *sa)
{
        struct addrinfo hints, *addrs;
        int rv;

        bzero(&hints, sizeof(hints));
        hints.ai_family = PF_UNSPEC;
        hints.ai_socktype = SOCK_STREAM;
        hints.ai_protocol = IPPROTO_TCP;

        if ((rv = getaddrinfo(word, "iscsi", &hints, &addrs)) == 0) {
                bcopy(addrs->ai_addr, sa, addrs->ai_addrlen);
                freeaddrinfo(addrs);
                return (0);
        }

        errx(1, "parse_host: %s", gai_strerror(rv));
}