/* vi: set sw=4 ts=4: */
/*
 * whois - tiny client for the whois directory service
 *
 * Copyright (c) 2011 Pere Orga <gotrunks@gmail.com>
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
/* TODO
 * Add ipv6 support
 * Add proxy support
 */
//config:config WHOIS
//config:       bool "whois (6.6 kb)"
//config:       default y
//config:       help
//config:       whois is a client for the whois directory service

//applet:IF_WHOIS(APPLET(whois, BB_DIR_USR_BIN, BB_SUID_DROP))

//kbuild:lib-$(CONFIG_WHOIS) += whois.o

//usage:#define whois_trivial_usage
//usage:       "[-i] [-h SERVER] [-p PORT] NAME..."
//usage:#define whois_full_usage "\n\n"
//usage:       "Query WHOIS info about NAME\n"
//usage:     "\n        -i      Show redirect results too"
//usage:     "\n        -h,-p   Server to query"

#include "libbb.h"

enum {
        OPT_i = (1 << 0),
};

static char *query(const char *host, int port, const char *domain)
{
        int fd;
        FILE *fp;
        bool success;
        char *redir = NULL;
        const char *pfx = "";
        char linebuf[1024];
        char *buf = NULL;
        unsigned bufpos = 0;

 again:
        printf("[Querying %s:%d '%s%s']\n", host, port, pfx, domain);
        fd = create_and_connect_stream_or_die(host, port);
        success = 0;
        fdprintf(fd, "%s%s\r\n", pfx, domain);
        fp = xfdopen_for_read(fd);

        while (fgets(linebuf, sizeof(linebuf), fp)) {
                unsigned len = strcspn(linebuf, "\r\n");
                linebuf[len++] = '\n';

                buf = xrealloc(buf, bufpos + len + 1);
                memcpy(buf + bufpos, linebuf, len);
                bufpos += len;
                buf[bufpos] = '\0';

                if (!redir || !success) {
                        trim(linebuf);
                        str_tolower(linebuf);
                        if (!success) {
                                success = is_prefixed_with(linebuf, "domain:")
                                       || is_prefixed_with(linebuf, "domain name:");
                        }
                        else if (!redir) {
                                char *p = is_prefixed_with(linebuf, "whois server:");
                                if (!p)
                                        p = is_prefixed_with(linebuf, "whois:");
                                if (p)
                                        redir = xstrdup(skip_whitespace(p));
                        }
                }
        }
        fclose(fp); /* closes fd too */
        if (!success && !pfx[0]) {
                /*
                 * Looking at /etc/jwhois.conf, some whois servers use
                 * "domain = DOMAIN", "DOMAIN ID <DOMAIN>"
                 * and "domain=DOMAIN_WITHOUT_LAST_COMPONENT"
                 * formats, but those are rare.
                 * (There are a few even more contrived ones.)
                 * We are trying only "domain DOMAIN", the typical one.
                 */
                pfx = "domain ";
                bufpos = 0;
                goto again;
        }

        /* Success */
        if (redir && strcmp(redir, host) == 0) {
                /* Redirect to self does not count */
                free(redir);
                redir = NULL;
        }
        if (!redir || (option_mask32 & OPT_i)) {
                /* Output saved text */
                printf("[%s]\n%s", host, buf ? buf : "");
        }
        free(buf);
        return redir;
}

static void recursive_query(const char *host, int port, const char *domain)
{
        char *free_me = NULL;
        char *redir;
 again:
        redir = query(host, port, domain);
        free(free_me);
        if (redir) {
                printf("[Redirected to %s]\n", redir);
                host = free_me = redir;
                port = 43;
                goto again;
        }
}

/* One of "big" whois implementations has these options:
 *
 * $ whois --help
 * jwhois version 4.0, Copyright (C) 1999-2007  Free Software Foundation, Inc.
 * -v, --verbose              verbose debug output
 * -c FILE, --config=FILE     use FILE as configuration file
 * -h HOST, --host=HOST       explicitly query HOST
 * -n, --no-redirect          disable content redirection
 * -s, --no-whoisservers      disable whois-servers.net service support
 * -a, --raw                  disable reformatting of the query
 * -i, --display-redirections display all redirects instead of hiding them
 * -p PORT, --port=PORT       use port number PORT (in conjunction with HOST)
 * -r, --rwhois               force an rwhois query to be made
 * --rwhois-display=DISPLAY   sets the display option in rwhois queries
 * --rwhois-limit=LIMIT       sets the maximum number of matches to return
 *
 * Example of its output:
 * $ whois cnn.com
 * [Querying whois.verisign-grs.com]
 * [Redirected to whois.corporatedomains.com]
 * [Querying whois.corporatedomains.com]
 * [whois.corporatedomains.com]
 * ...text of the reply...
 *
 * With -i, reply from each server is printed, after all redirects are done:
 * [Querying whois.verisign-grs.com]
 * [Redirected to whois.corporatedomains.com]
 * [Querying whois.corporatedomains.com]
 * [whois.verisign-grs.com]
 * ...text of the reply...
 * [whois.corporatedomains.com]
 * ...text of the reply...
 *
 * With -a, no "DOMAIN" -> "domain DOMAIN" transformation is attempted.

 * With -n, the first reply is shown, redirects are not followed:
 * [Querying whois.verisign-grs.com]
 * [whois.verisign-grs.com]
 * ...text of the reply...
 */

int whois_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int whois_main(int argc UNUSED_PARAM, char **argv)
{
        int port = 43;
        const char *host = "whois.iana.org";

        getopt32(argv, "^" "ih:p:+" "\0" "-1", &host, &port);
        argv += optind;

        do {
                recursive_query(host, port, *argv);
        }
        while (*++argv);

        return EXIT_SUCCESS;
}