source: otr.c @ 2370ec2

  /********************************************************************\
  * BitlBee -- An IRC to other IM-networks gateway                     *
  *                                                                    *
  * Copyright 2002-2010 Wilmer van der Gaast and others                *
  \********************************************************************/

/*
  OTR support (cf. http://www.cypherpunks.ca/otr/)
  
  (c) 2008-2010 Sven Moritz Hallberg <pesco@khjk.org>
  (c) 2008 funded by stonedcoder.org
    
  files used to store OTR data:
    <configdir>/<nick>.otr_keys
    <configdir>/<nick>.otr_fprints
    
  top-level todos: (search for TODO for more ;-))
    integrate otr_load/otr_save with existing storage backends
    per-account policy settings
    per-user policy settings
*/

/*
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License with
  the Debian GNU/Linux distribution in /usr/share/common-licenses/GPL;
  if not, write to the Free Software Foundation, Inc., 59 Temple Place,
  Suite 330, Boston, MA  02111-1307  USA
*/

#include "bitlbee.h"
#include "irc.h"
#include "otr.h"
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <assert.h>
#include <signal.h>


/** OTR interface routines for the OtrlMessageAppOps struct: **/

OtrlPolicy op_policy(void *opdata, ConnContext *context);

void op_create_privkey(void *opdata, const char *accountname, const char *protocol);

int op_is_logged_in(void *opdata, const char *accountname, const char *protocol,
        const char *recipient);

void op_inject_message(void *opdata, const char *accountname, const char *protocol,
        const char *recipient, const char *message);

int op_display_otr_message(void *opdata, const char *accountname, const char *protocol,
        const char *username, const char *msg);

void op_new_fingerprint(void *opdata, OtrlUserState us, const char *accountname,
        const char *protocol, const char *username, unsigned char fingerprint[20]);

void op_write_fingerprints(void *opdata);

void op_gone_secure(void *opdata, ConnContext *context);

void op_gone_insecure(void *opdata, ConnContext *context);

void op_still_secure(void *opdata, ConnContext *context, int is_reply);

void op_log_message(void *opdata, const char *message);

int op_max_message_size(void *opdata, ConnContext *context);

const char *op_account_name(void *opdata, const char *account, const char *protocol);


/** otr sub-command handlers: **/

static void cmd_otr(irc_t *irc, char **args);
void cmd_otr_connect(irc_t *irc, char **args);
void cmd_otr_disconnect(irc_t *irc, char **args);
void cmd_otr_reconnect(irc_t *irc, char **args);
void cmd_otr_smp(irc_t *irc, char **args);
void cmd_otr_smpq(irc_t *irc, char **args);
void cmd_otr_trust(irc_t *irc, char **args);
void cmd_otr_info(irc_t *irc, char **args);
void cmd_otr_keygen(irc_t *irc, char **args);
void cmd_otr_forget(irc_t *irc, char **args);

const command_t otr_commands[] = {
        { "connect",     1, &cmd_otr_connect,    0 },
        { "disconnect",  1, &cmd_otr_disconnect, 0 },
        { "reconnect",   1, &cmd_otr_reconnect,  0 },
        { "smp",         2, &cmd_otr_smp,        0 },
        { "smpq",        3, &cmd_otr_smpq,       0 },
        { "trust",       6, &cmd_otr_trust,      0 },
        { "info",        0, &cmd_otr_info,       0 },
        { "keygen",      1, &cmd_otr_keygen,     0 },
        { "forget",      2, &cmd_otr_forget,     0 },
        { NULL }
};

typedef struct {
        void *fst;
        void *snd;
} pair_t;       

static OtrlMessageAppOps otr_ops;   /* collects interface functions required by OTR */


/** misc. helpers/subroutines: **/

/* check whether we are already generating a key for a given account */
int keygen_in_progress(irc_t *irc, const char *handle, const char *protocol);

/* start background process to generate a (new) key for a given account */
void otr_keygen(irc_t *irc, const char *handle, const char *protocol);

/* main function for the forked keygen slave */
void keygen_child_main(OtrlUserState us, int infd, int outfd);

/* mainloop handler for when a keygen finishes */
gboolean keygen_finish_handler(gpointer data, gint fd, b_input_condition cond);

/* copy the contents of file a to file b, overwriting it if it exists */
void copyfile(const char *a, const char *b);

/* read one line of input from a stream, excluding trailing newline */
void myfgets(char *s, int size, FILE *stream);

/* some yes/no handlers */
void yes_keygen(void *data);
void yes_forget_fingerprint(void *data);
void yes_forget_context(void *data);
void yes_forget_key(void *data);

/* helper to make sure accountname and protocol match the incoming "opdata" */
struct im_connection *check_imc(void *opdata, const char *accountname,
        const char *protocol);

/* determine the nick for a given handle/protocol pair
   returns "handle/protocol" if not found */
const char *peernick(irc_t *irc, const char *handle, const char *protocol);

/* turn a hexadecimal digit into its numerical value */
int hexval(char a);

/* determine the irc_user_t for a given handle/protocol pair
   returns NULL if not found */
irc_user_t *peeruser(irc_t *irc, const char *handle, const char *protocol);

/* handle SMP TLVs from a received message */
void otr_handle_smp(struct im_connection *ic, const char *handle, OtrlTLV *tlvs);

/* combined handler for the 'otr smp' and 'otr smpq' commands */
void otr_smp_or_smpq(irc_t *irc, const char *nick, const char *question,
                const char *secret);

/* update op/voice flag of given user according to encryption state and settings
   returns 0 if neither op_buddies nor voice_buddies is set to "encrypted",
   i.e. msgstate should be announced seperately */
int otr_update_modeflags(irc_t *irc, irc_user_t *u);

/* show general info about the OTR subsystem; called by 'otr info' */
void show_general_otr_info(irc_t *irc);

/* show info about a given OTR context */
void show_otr_context_info(irc_t *irc, ConnContext *ctx);

/* show the list of fingerprints associated with a given context */
void show_fingerprints(irc_t *irc, ConnContext *ctx);

/* find a fingerprint by prefix (given as any number of hex strings) */
Fingerprint *match_fingerprint(irc_t *irc, ConnContext *ctx, const char **args);

/* find a private key by fingerprint prefix (given as any number of hex strings) */
OtrlPrivKey *match_privkey(irc_t *irc, const char **args);

/* functions to be called for certain events */
static const struct irc_plugin otr_plugin;


/*** routines declared in otr.h: ***/

#ifdef OTR_BI
#define init_plugin otr_init
#endif

void init_plugin(void)
{
        OTRL_INIT;
        
        /* fill global OtrlMessageAppOps */
        otr_ops.policy = &op_policy;
        otr_ops.create_privkey = &op_create_privkey;
        otr_ops.is_logged_in = &op_is_logged_in;
        otr_ops.inject_message = &op_inject_message;
        otr_ops.notify = NULL;
        otr_ops.display_otr_message = &op_display_otr_message;
        otr_ops.update_context_list = NULL;
        otr_ops.protocol_name = NULL;
        otr_ops.protocol_name_free = NULL;
        otr_ops.new_fingerprint = &op_new_fingerprint;
        otr_ops.write_fingerprints = &op_write_fingerprints;
        otr_ops.gone_secure = &op_gone_secure;
        otr_ops.gone_insecure = &op_gone_insecure;
        otr_ops.still_secure = &op_still_secure;
        otr_ops.log_message = &op_log_message;
        otr_ops.max_message_size = &op_max_message_size;
        otr_ops.account_name = &op_account_name;
        otr_ops.account_name_free = NULL;
        
        root_command_add( "otr", 1, cmd_otr, 0 );
        register_irc_plugin( &otr_plugin );
}

gboolean otr_irc_new(irc_t *irc)
{
        set_t *s;
        GSList *l;
        
        irc->otr = g_new0(otr_t, 1);
        irc->otr->us = otrl_userstate_create();
        
        s = set_add( &irc->b->set, "otr_color_encrypted", "true", set_eval_bool, irc );
        
        s = set_add( &irc->b->set, "otr_policy", "oppurtunistic", set_eval_list, irc );
        l = g_slist_prepend( NULL, "never" );
        l = g_slist_prepend( l, "opportunistic" );
        l = g_slist_prepend( l, "manual" );
        l = g_slist_prepend( l, "always" );
        s->eval_data = l;
        
        return TRUE;
}

void otr_irc_free(irc_t *irc)
{
        otr_t *otr = irc->otr;
        otrl_userstate_free(otr->us);
        if(otr->keygen) {
                kill(otr->keygen, SIGTERM);
                waitpid(otr->keygen, NULL, 0);
                /* TODO: remove stale keygen tempfiles */
        }
        if(otr->to)
                fclose(otr->to);
        if(otr->from)
                fclose(otr->from);
        while(otr->todo) {
                kg_t *p = otr->todo;
                otr->todo = p->next;
                g_free(p);
        }
        g_free(otr);
}

void otr_load(irc_t *irc)
{
        char s[512];
        account_t *a;
        gcry_error_t e;
        gcry_error_t enoent = gcry_error_from_errno(ENOENT);
        int kg=0;

        g_snprintf(s, 511, "%s%s.otr_keys", global.conf->configdir, irc->user->nick);
        e = otrl_privkey_read(irc->otr->us, s);
        if(e && e!=enoent) {
                irc_usermsg(irc, "otr load: %s: %s", s, gcry_strerror(e));
        }
        g_snprintf(s, 511, "%s%s.otr_fprints", global.conf->configdir, irc->user->nick);
        e = otrl_privkey_read_fingerprints(irc->otr->us, s, NULL, NULL);
        if(e && e!=enoent) {
                irc_usermsg(irc, "otr load: %s: %s", s, gcry_strerror(e));
        }
        
        /* check for otr keys on all accounts */
        for(a=irc->b->accounts; a; a=a->next) {
                kg = otr_check_for_key(a) || kg;
        }
        if(kg) {
                irc_usermsg(irc, "Notice: "
                        "The accounts above do not have OTR encryption keys associated with them, yet. "
                        "These keys are now being generated in the background. "
                        "You will be notified as they are completed. "
                        "It is not necessary to wait; "
                        "BitlBee can be used normally during key generation. "
                        "You may safely ignore this message if you don't know what OTR is. ;)");
        }
}

void otr_save(irc_t *irc)
{
        char s[512];
        gcry_error_t e;

        g_snprintf(s, 511, "%s%s.otr_fprints", global.conf->configdir, irc->user->nick);
        e = otrl_privkey_write_fingerprints(irc->otr->us, s);
        if(e) {
                irc_usermsg(irc, "otr save: %s: %s", s, gcry_strerror(e));
        }
        chmod(s, 0600);
}

void otr_remove(const char *nick)
{
        char s[512];
        
        g_snprintf(s, 511, "%s%s.otr_keys", global.conf->configdir, nick);
        unlink(s);
        g_snprintf(s, 511, "%s%s.otr_fprints", global.conf->configdir, nick);
        unlink(s);
}

void otr_rename(const char *onick, const char *nnick)
{
        char s[512], t[512];
        
        g_snprintf(s, 511, "%s%s.otr_keys", global.conf->configdir, onick);
        g_snprintf(t, 511, "%s%s.otr_keys", global.conf->configdir, nnick);
        rename(s,t);
        g_snprintf(s, 511, "%s%s.otr_fprints", global.conf->configdir, onick);
        g_snprintf(t, 511, "%s%s.otr_fprints", global.conf->configdir, nnick);
        rename(s,t);
}

int otr_check_for_key(account_t *a)
{
        irc_t *irc = a->bee->ui_data;
        OtrlPrivKey *k;
        
        /* don't do OTR on certain (not classic IM) protocols, e.g. twitter */
        if(a->prpl->options & OPT_NOOTR) {
                return 0;
        }
        
        k = otrl_privkey_find(irc->otr->us, a->user, a->prpl->name);
        if(k) {
                irc_usermsg(irc, "otr: %s/%s ready", a->user, a->prpl->name);
                return 0;
        } if(keygen_in_progress(irc, a->user, a->prpl->name)) {
                irc_usermsg(irc, "otr: keygen for %s/%s already in progress", a->user, a->prpl->name);
                return 0;
        } else {
                irc_usermsg(irc, "otr: starting background keygen for %s/%s", a->user, a->prpl->name);
                otr_keygen(irc, a->user, a->prpl->name);
                return 1;
        }
}

char *otr_filter_msg_in(irc_user_t *iu, char *msg, int flags)
{
        int ignore_msg;
        char *newmsg = NULL;
        OtrlTLV *tlvs = NULL;
        char *colormsg;
        irc_t *irc = iu->irc;
        struct im_connection *ic = iu->bu->ic;
        
        /* don't do OTR on certain (not classic IM) protocols, e.g. twitter */
        if(ic->acc->prpl->options & OPT_NOOTR) {
                return msg;
        }
        
        ignore_msg = otrl_message_receiving(irc->otr->us, &otr_ops, ic,
                ic->acc->user, ic->acc->prpl->name, iu->bu->handle, msg, &newmsg,
                &tlvs, NULL, NULL);

        otr_handle_smp(ic, iu->bu->handle, tlvs);
        
        if(ignore_msg) {
                /* this was an internal OTR protocol message */
                return NULL;
        } else if(!newmsg) {
                /* this was a non-OTR message */
                return g_strdup(msg);
        } else {
                /* OTR has processed this message */
                ConnContext *context = otrl_context_find(irc->otr->us, iu->bu->handle,
                        ic->acc->user, ic->acc->prpl->name, 0, NULL, NULL, NULL);
                if(context && context->msgstate == OTRL_MSGSTATE_ENCRYPTED &&
                   set_getbool(&ic->bee->set, "otr_color_encrypted")) {
                        /* color according to f'print trust */
                        int color;
                        const char *trust = context->active_fingerprint->trust;
                        if(trust && trust[0] != '\0')
                                color=3;   /* green */
                        else
                                color=5;   /* red */

                        if(newmsg[0] == ',') {
                                /* could be a problem with the color code */
                                /* insert a space between color spec and message */
                                colormsg = g_strdup_printf("\x03%.2d %s\x0F", color, newmsg);
                        } else {
                                colormsg = g_strdup_printf("\x03%.2d%s\x0F", color, newmsg);
                        }
                } else {
                        colormsg = g_strdup(newmsg);
                }
                otrl_message_free(newmsg);
                return colormsg;
        }
}

char *otr_filter_msg_out(irc_user_t *iu, char *msg, int flags)
{       
        int st;
        char *otrmsg = NULL;
        ConnContext *ctx = NULL;
        irc_t *irc = iu->irc;
        struct im_connection *ic = iu->bu->ic;

        /* don't do OTR on certain (not classic IM) protocols, e.g. twitter */
        if(ic->acc->prpl->options & OPT_NOOTR) {
                return msg;
        }
        
        st = otrl_message_sending(irc->otr->us, &otr_ops, ic,
                ic->acc->user, ic->acc->prpl->name, iu->bu->handle,
                msg, NULL, &otrmsg, NULL, NULL);
        if(st) {
                return NULL;
        }

        ctx = otrl_context_find(irc->otr->us,
                        iu->bu->handle, ic->acc->user, ic->acc->prpl->name,
                        1, NULL, NULL, NULL);

        if(otrmsg) {
                if(!ctx) {
                        otrl_message_free(otrmsg);
                        return NULL;
                }
                st = otrl_message_fragment_and_send(&otr_ops, ic, ctx,
                        otrmsg, OTRL_FRAGMENT_SEND_ALL, NULL);
                otrl_message_free(otrmsg);
        } else {
                /* note: otrl_message_sending handles policy, so that if REQUIRE_ENCRYPTION is set,
                   this case does not occur */
                return msg;
        }
        
        /* TODO: Error reporting should be done here now (if st!=0), probably. */
        
        return NULL;
}

static const struct irc_plugin otr_plugin =
{
        otr_irc_new,
        otr_irc_free,
        otr_filter_msg_out,
        otr_filter_msg_in,
        otr_load,
        otr_save,
        otr_remove,
};

static void cmd_otr(irc_t *irc, char **args)
{
        const command_t *cmd;
        
        if(!args[0])
                return;
        
        if(!args[1])
                return;
        
        for(cmd=otr_commands; cmd->command; cmd++) {
                if(strcmp(cmd->command, args[1]) == 0)
                        break;
        }
        
        if(!cmd->command) {
                irc_usermsg(irc, "%s: unknown subcommand \"%s\", see \x02help otr\x02",
                        args[0], args[1]);
                return;
        }
        
        if(!args[cmd->required_parameters+1]) {
                irc_usermsg(irc, "%s %s: not enough arguments (%d req.)",
                        args[0], args[1], cmd->required_parameters);
                return;
        }
        
        cmd->execute(irc, args+1);
}


/*** OTR "MessageAppOps" callbacks for global.otr_ui: ***/

OtrlPolicy op_policy(void *opdata, ConnContext *context)
{
        struct im_connection *ic = check_imc(opdata, context->accountname, context->protocol);
        irc_t *irc = ic->bee->ui_data;
        const char *p;
        
        /* policy override during keygen: if we're missing the key for context but are currently
           generating it, then that's as much as we can do. => temporarily return NEVER. */
        if(keygen_in_progress(irc, context->accountname, context->protocol) &&
           !otrl_privkey_find(irc->otr->us, context->accountname, context->protocol))
                return OTRL_POLICY_NEVER;

        p = set_getstr(&ic->bee->set, "otr_policy");
        if(!strcmp(p, "never"))
                return OTRL_POLICY_NEVER;
        if(!strcmp(p, "opportunistic"))
                return OTRL_POLICY_OPPORTUNISTIC;
        if(!strcmp(p, "manual"))
                return OTRL_POLICY_MANUAL;
        if(!strcmp(p, "always"))
                return OTRL_POLICY_ALWAYS;
        
        return OTRL_POLICY_OPPORTUNISTIC;
}

void op_create_privkey(void *opdata, const char *accountname,
        const char *protocol)
{
        struct im_connection *ic = check_imc(opdata, accountname, protocol);
        irc_t *irc = ic->bee->ui_data;
        
        /* will fail silently if keygen already in progress */
        otr_keygen(irc, accountname, protocol);
}

int op_is_logged_in(void *opdata, const char *accountname,
        const char *protocol, const char *recipient)
{
        struct im_connection *ic = check_imc(opdata, accountname, protocol);
        bee_user_t *bu;

        /* lookup the irc_user_t for the given recipient */
        bu = bee_user_by_handle(ic->bee, ic, recipient);
        if(bu) {
                if(bu->flags & BEE_USER_ONLINE)
                        return 1;
                else
                        return 0;
        } else {
                return -1;
        }
}

void op_inject_message(void *opdata, const char *accountname,
        const char *protocol, const char *recipient, const char *message)
{
        struct im_connection *ic = check_imc(opdata, accountname, protocol);
        irc_t *irc = ic->bee->ui_data;

        if (strcmp(accountname, recipient) == 0) {
                /* huh? injecting messages to myself? */
                irc_usermsg(irc, "note to self: %s", message);
        } else {
                /* need to drop some consts here :-( */
                /* TODO: get flags into op_inject_message?! */
                ic->acc->prpl->buddy_msg(ic, (char *)recipient, (char *)message, 0);
                /* ignoring return value :-/ */
        }
}

int op_display_otr_message(void *opdata, const char *accountname,
        const char *protocol, const char *username, const char *message)
{
        struct im_connection *ic = check_imc(opdata, accountname, protocol);
        char *msg = g_strdup(message);
        irc_t *irc = ic->bee->ui_data;

        strip_html(msg);
        irc_usermsg(irc, "otr: %s", msg);

        g_free(msg);
        return 0;
}

void op_new_fingerprint(void *opdata, OtrlUserState us,
        const char *accountname, const char *protocol,
        const char *username, unsigned char fingerprint[20])
{
        struct im_connection *ic = check_imc(opdata, accountname, protocol);
        irc_t *irc = ic->bee->ui_data;
        char hunam[45];         /* anybody looking? ;-) */
        
        otrl_privkey_hash_to_human(hunam, fingerprint);
        irc_usermsg(irc, "new fingerprint for %s: %s",
                peernick(irc, username, protocol), hunam);
}

void op_write_fingerprints(void *opdata)
{
        struct im_connection *ic = (struct im_connection *)opdata;
        irc_t *irc = ic->bee->ui_data;

        otr_save(irc);
}

void op_gone_secure(void *opdata, ConnContext *context)
{
        struct im_connection *ic =
                check_imc(opdata, context->accountname, context->protocol);
        irc_user_t *u;
        irc_t *irc = ic->bee->ui_data;
        const char *trust;

        u = peeruser(irc, context->username, context->protocol);
        if(!u) {
                log_message(LOGLVL_ERROR,
                        "BUG: otr.c: op_gone_secure: irc_user_t for %s/%s/%s not found!",
                        context->username, context->protocol, context->accountname);
                return;
        }
        
        trust = context->active_fingerprint->trust;
        if(trust && trust[0])
                u->flags |= IRC_USER_OTR_ENCRYPTED | IRC_USER_OTR_TRUSTED;
        else
                u->flags = ( u->flags & ~IRC_USER_OTR_TRUSTED ) | IRC_USER_OTR_ENCRYPTED;
        if(!otr_update_modeflags(irc, u))
                irc_usermsg(irc, "conversation with %s is now off the record", u->nick);
}

void op_gone_insecure(void *opdata, ConnContext *context)
{
        struct im_connection *ic =
                check_imc(opdata, context->accountname, context->protocol);
        irc_t *irc = ic->bee->ui_data;
        irc_user_t *u;

        u = peeruser(irc, context->username, context->protocol);
        if(!u) {
                log_message(LOGLVL_ERROR,
                        "BUG: otr.c: op_gone_insecure: irc_user_t for %s/%s/%s not found!",
                        context->username, context->protocol, context->accountname);
                return;
        }
        u->flags &= ~( IRC_USER_OTR_ENCRYPTED | IRC_USER_OTR_TRUSTED );
        if(!otr_update_modeflags(irc, u))
                irc_usermsg(irc, "conversation with %s is now in the clear", u->nick);
}

void op_still_secure(void *opdata, ConnContext *context, int is_reply)
{
        struct im_connection *ic =
                check_imc(opdata, context->accountname, context->protocol);
        irc_t *irc = ic->bee->ui_data;
        irc_user_t *u;

        u = peeruser(irc, context->username, context->protocol);
        if(!u) {
                log_message(LOGLVL_ERROR,
                        "BUG: otr.c: op_still_secure: irc_user_t for %s/%s/%s not found!",
                        context->username, context->protocol, context->accountname);
                return;
        }
        if(context->active_fingerprint->trust[0])
                u->flags |= IRC_USER_OTR_ENCRYPTED | IRC_USER_OTR_TRUSTED;
        else
                u->flags = ( u->flags & ~IRC_USER_OTR_TRUSTED ) | IRC_USER_OTR_ENCRYPTED;
        if(!otr_update_modeflags(irc, u))
                irc_usermsg(irc, "otr connection with %s has been refreshed", u->nick);
}

void op_log_message(void *opdata, const char *message)
{
        char *msg = g_strdup(message);
        
        strip_html(msg);
        log_message(LOGLVL_INFO, "otr: %s", msg);
        g_free(msg);
}

int op_max_message_size(void *opdata, ConnContext *context)
{
        struct im_connection *ic =
                check_imc(opdata, context->accountname, context->protocol);

        return ic->acc->prpl->mms;
}

const char *op_account_name(void *opdata, const char *account, const char *protocol)
{
        struct im_connection *ic = (struct im_connection *)opdata;
        irc_t *irc = ic->bee->ui_data;

        return peernick(irc, account, protocol);
}


/*** OTR sub-command handlers ***/

void cmd_otr_reconnect(irc_t *irc, char **args)
{
        cmd_otr_disconnect(irc, args);
        cmd_otr_connect(irc, args);
}

void cmd_otr_disconnect(irc_t *irc, char **args)
{
        irc_user_t *u;

        u = irc_user_by_name(irc, args[1]);
        if(!u || !u->bu || !u->bu->ic) {
                irc_usermsg(irc, "%s: unknown user", args[1]);
                return;
        }
        
        otrl_message_disconnect(irc->otr->us, &otr_ops,
                u->bu->ic, u->bu->ic->acc->user, u->bu->ic->acc->prpl->name, u->bu->handle);
        
        /* for some reason, libotr (3.1.0) doesn't do this itself: */
        if(u->flags & IRC_USER_OTR_ENCRYPTED) {
                ConnContext *ctx;
                ctx = otrl_context_find(irc->otr->us, u->bu->handle, u->bu->ic->acc->user,
                        u->bu->ic->acc->prpl->name, 0, NULL, NULL, NULL);
                if(ctx)
                        op_gone_insecure(u->bu->ic, ctx);
                else /* huh? */
                        u->flags &= ( IRC_USER_OTR_ENCRYPTED | IRC_USER_OTR_TRUSTED );
        }
}

void cmd_otr_connect(irc_t *irc, char **args)
{
        irc_user_t *u;

        u = irc_user_by_name(irc, args[1]);
        if(!u || !u->bu || !u->bu->ic) {
                irc_usermsg(irc, "%s: unknown user", args[1]);
                return;
        }
        if(!(u->bu->flags & BEE_USER_ONLINE)) {
                irc_usermsg(irc, "%s is offline", args[1]);
                return;
        }
        
        bee_user_msg(irc->b, u->bu, "?OTR?v2?", 0);
}

void cmd_otr_smp(irc_t *irc, char **args)
{
        otr_smp_or_smpq(irc, args[1], NULL, args[2]);   /* no question */
}

void cmd_otr_smpq(irc_t *irc, char **args)
{
        otr_smp_or_smpq(irc, args[1], args[2], args[3]);
}

void cmd_otr_trust(irc_t *irc, char **args)
{
        irc_user_t *u;
        ConnContext *ctx;
        unsigned char raw[20];
        Fingerprint *fp;
        int i,j;
        
        u = irc_user_by_name(irc, args[1]);
        if(!u || !u->bu || !u->bu->ic) {
                irc_usermsg(irc, "%s: unknown user", args[1]);
                return;
        }
        
        ctx = otrl_context_find(irc->otr->us, u->bu->handle,
                u->bu->ic->acc->user, u->bu->ic->acc->prpl->name, 0, NULL, NULL, NULL);
        if(!ctx) {
                irc_usermsg(irc, "%s: no otr context with user", args[1]);
                return;
        }
        
        /* convert given fingerprint to raw representation */
        for(i=0; i<5; i++) {
                for(j=0; j<4; j++) {
                        char *p = args[2+i]+(2*j);
                        char *q = p+1;
                        int x, y;
                        
                        if(!*p || !*q) {
                                irc_usermsg(irc, "failed: truncated fingerprint block %d", i+1);
                                return;
                        }
                        
                        x = hexval(*p);
                        y = hexval(*q);
                        if(x<0) {
                                irc_usermsg(irc, "failed: %d. hex digit of block %d out of range", 2*j+1, i+1);
                                return;
                        }
                        if(y<0) {
                                irc_usermsg(irc, "failed: %d. hex digit of block %d out of range", 2*j+2, i+1);
                                return;
                        }

                        raw[i*4+j] = x*16 + y;
                }
        }
        fp = otrl_context_find_fingerprint(ctx, raw, 0, NULL);
        if(!fp) {
                irc_usermsg(irc, "failed: no such fingerprint for %s", args[1]);
        } else {
                char *trust = args[7] ? args[7] : "affirmed";
                otrl_context_set_trust(fp, trust);
                irc_usermsg(irc, "fingerprint match, trust set to \"%s\"", trust);
                if(u->flags & IRC_USER_OTR_ENCRYPTED)
                        u->flags |= IRC_USER_OTR_TRUSTED;
                otr_update_modeflags(irc, u);
        }
}

void cmd_otr_info(irc_t *irc, char **args)
{
        if(!args[1]) {
                show_general_otr_info(irc);
        } else {
                char *arg = g_strdup(args[1]);
                char *myhandle, *handle=NULL, *protocol;
                ConnContext *ctx;
                
                /* interpret arg as 'user/protocol/account' if possible */
                protocol = strchr(arg, '/');
                myhandle = NULL;
                if(protocol) {
                        *(protocol++) = '\0';
                        myhandle = strchr(protocol, '/');
                }
                if(protocol && myhandle) {
                        *(myhandle++) = '\0';
                        handle = arg;
                        ctx = otrl_context_find(irc->otr->us, handle, myhandle, protocol, 0, NULL, NULL, NULL);
                        if(!ctx) {
                                irc_usermsg(irc, "no such context");
                                g_free(arg);
                                return;
                        }
                } else {
                        irc_user_t *u = irc_user_by_name(irc, args[1]);
                        if(!u || !u->bu || !u->bu->ic) {
                                irc_usermsg(irc, "%s: unknown user", args[1]);
                                g_free(arg);
                                return;
                        }
                        ctx = otrl_context_find(irc->otr->us, u->bu->handle, u->bu->ic->acc->user,
                                u->bu->ic->acc->prpl->name, 0, NULL, NULL, NULL);
                        if(!ctx) {
                                irc_usermsg(irc, "no otr context with %s", args[1]);
                                g_free(arg);
                                return;
                        }
                }
        
                /* show how we resolved the (nick) argument, if we did */
                if(handle!=arg) {
                        irc_usermsg(irc, "%s is %s/%s; we are %s/%s to them", args[1],
                                ctx->username, ctx->protocol, ctx->accountname, ctx->protocol);
                }
                show_otr_context_info(irc, ctx);
                g_free(arg);
        }
}

void cmd_otr_keygen(irc_t *irc, char **args)
{
        int i, n;
        account_t *a;
        
        n = atoi(args[1]);
        if(n<0 || (!n && strcmp(args[1], "0"))) {
                irc_usermsg(irc, "%s: invalid account number", args[1]);
                return;
        }
        
        a = irc->b->accounts;
        for(i=0; i<n && a; i++, a=a->next);
        if(!a) {
                irc_usermsg(irc, "%s: no such account", args[1]);
                return;
        }
        
        if(keygen_in_progress(irc, a->user, a->prpl->name)) {
                irc_usermsg(irc, "keygen for account %d already in progress", n);
                return;
        }
        
        if(otrl_privkey_find(irc->otr->us, a->user, a->prpl->name)) {
                char *s = g_strdup_printf("account %d already has a key, replace it?", n);
                query_add(irc, NULL, s, yes_keygen, NULL, NULL, a);
                g_free(s);
        } else {
                otr_keygen(irc, a->user, a->prpl->name);
        }
}

void yes_forget_fingerprint(void *data)
{
        pair_t *p = (pair_t *)data;
        irc_t *irc = (irc_t *)p->fst;
        Fingerprint *fp = (Fingerprint *)p->snd;

        g_free(p);
        
        if(fp == fp->context->active_fingerprint) {
                irc_usermsg(irc, "that fingerprint is active, terminate otr connection first");
                return;
        }
                
        otrl_context_forget_fingerprint(fp, 0);
}

void yes_forget_context(void *data)
{
        pair_t *p = (pair_t *)data;
        irc_t *irc = (irc_t *)p->fst;
        ConnContext *ctx = (ConnContext *)p->snd;

        g_free(p);
        
        if(ctx->msgstate == OTRL_MSGSTATE_ENCRYPTED) {
                irc_usermsg(irc, "active otr connection with %s, terminate it first",
                        peernick(irc, ctx->username, ctx->protocol));
                return;
        }
                
        if(ctx->msgstate == OTRL_MSGSTATE_FINISHED)
                otrl_context_force_plaintext(ctx);
        otrl_context_forget(ctx);
}

void yes_forget_key(void *data)
{
        OtrlPrivKey *key = (OtrlPrivKey *)data;
        
        otrl_privkey_forget(key);
        /* Hm, libotr doesn't seem to offer a function for explicitly /writing/
           keyfiles. So the key will be back on the next load... */
        /* TODO: Actually erase forgotten keys from storage? */
}

void cmd_otr_forget(irc_t *irc, char **args)
{
        if(!strcmp(args[1], "fingerprint"))
        {
                irc_user_t *u;
                ConnContext *ctx;
                Fingerprint *fp;
                char human[54];
                char *s;
                pair_t *p;
                
                if(!args[3]) {
                        irc_usermsg(irc, "otr %s %s: not enough arguments (2 req.)", args[0], args[1]);
                        return;
                }
                
                /* TODO: allow context specs ("user/proto/account") in 'otr forget fingerprint'? */
                u = irc_user_by_name(irc, args[2]);
                if(!u || !u->bu || !u->bu->ic) {
                        irc_usermsg(irc, "%s: unknown user", args[2]);
                        return;
                }
                
                ctx = otrl_context_find(irc->otr->us, u->bu->handle, u->bu->ic->acc->user,
                        u->bu->ic->acc->prpl->name, 0, NULL, NULL, NULL);
                if(!ctx) {
                        irc_usermsg(irc, "no otr context with %s", args[2]);
                        return;
                }
                
                fp = match_fingerprint(irc, ctx, ((const char **)args)+3);
                if(!fp) {
                        /* match_fingerprint does error messages */
                        return;
                }
                
                if(fp == ctx->active_fingerprint) {
                        irc_usermsg(irc, "that fingerprint is active, terminate otr connection first");
                        return;
                }
                
                otrl_privkey_hash_to_human(human, fp->fingerprint);
                s = g_strdup_printf("about to forget fingerprint %s, are you sure?", human);
                p = g_malloc(sizeof(pair_t));
                if(!p)
                        return;
                p->fst = irc;
                p->snd = fp;
                query_add(irc, NULL, s, yes_forget_fingerprint, NULL, NULL, p);
                g_free(s);
        }
        
        else if(!strcmp(args[1], "context"))
        {
                irc_user_t *u;
                ConnContext *ctx;
                char *s;
                pair_t *p;
                
                /* TODO: allow context specs ("user/proto/account") in 'otr forget contex'? */
                u = irc_user_by_name(irc, args[2]);
                if(!u || !u->bu || !u->bu->ic) {
                        irc_usermsg(irc, "%s: unknown user", args[2]);
                        return;
                }
                
                ctx = otrl_context_find(irc->otr->us, u->bu->handle, u->bu->ic->acc->user,
                        u->bu->ic->acc->prpl->name, 0, NULL, NULL, NULL);
                if(!ctx) {
                        irc_usermsg(irc, "no otr context with %s", args[2]);
                        return;
                }
                
                if(ctx->msgstate == OTRL_MSGSTATE_ENCRYPTED) {
                        irc_usermsg(irc, "active otr connection with %s, terminate it first", args[2]);
                        return;
                }
                
                s = g_strdup_printf("about to forget otr data about %s, are you sure?", args[2]);
                p = g_malloc(sizeof(pair_t));
                if(!p)
                        return;
                p->fst = irc;
                p->snd = ctx;
                query_add(irc, NULL, s, yes_forget_context, NULL, NULL, p);
                g_free(s);
        }
        
        else if(!strcmp(args[1], "key"))
        {
                OtrlPrivKey *key;
                char *s;
                
                key = match_privkey(irc, ((const char **)args)+2);
                if(!key) {
                        /* match_privkey does error messages */
                        return;
                }
                
                s = g_strdup_printf("about to forget the private key for %s/%s, are you sure?",
                        key->accountname, key->protocol);
                query_add(irc, NULL, s, yes_forget_key, NULL, NULL, key);
                g_free(s);
        }
        
        else
        {
                irc_usermsg(irc, "otr %s: unknown subcommand \"%s\", see \x02help otr forget\x02",
                        args[0], args[1]);
        }
}


/*** local helpers / subroutines: ***/

/* Socialist Millionaires' Protocol */
void otr_handle_smp(struct im_connection *ic, const char *handle, OtrlTLV *tlvs)
{
        irc_t *irc = ic->bee->ui_data;
        OtrlUserState us = irc->otr->us;
        OtrlMessageAppOps *ops = &otr_ops;
        OtrlTLV *tlv = NULL;
        ConnContext *context;
        NextExpectedSMP nextMsg;
        irc_user_t *u;
        bee_user_t *bu;

        bu = bee_user_by_handle(ic->bee, ic, handle);
        if(!bu || !(u = bu->ui_data)) return;
        context = otrl_context_find(us, handle,
                ic->acc->user, ic->acc->prpl->name, 1, NULL, NULL, NULL);
        if(!context) {
                /* huh? out of memory or what? */
                irc_usermsg(irc, "smp: failed to get otr context for %s", u->nick);
                otrl_message_abort_smp(us, ops, u->bu->ic, context);
                otrl_sm_state_free(context->smstate);
                return;
        }
        nextMsg = context->smstate->nextExpected;

        if (context->smstate->sm_prog_state == OTRL_SMP_PROG_CHEATED) {
                irc_usermsg(irc, "smp %s: opponent violated protocol, aborting",
                        u->nick);
                otrl_message_abort_smp(us, ops, u->bu->ic, context);
                otrl_sm_state_free(context->smstate);
                return;
        }

        tlv = otrl_tlv_find(tlvs, OTRL_TLV_SMP1Q);
        if (tlv) {
                if (nextMsg != OTRL_SMP_EXPECT1) {
                        irc_usermsg(irc, "smp %s: spurious SMP1Q received, aborting", u->nick);
                        otrl_message_abort_smp(us, ops, u->bu->ic, context);
                        otrl_sm_state_free(context->smstate);
                } else {
                        char *question = g_strndup((char *)tlv->data, tlv->len);
                        irc_usermsg(irc, "smp: initiated by %s with question: \x02\"%s\"\x02", u->nick,
                                question);
                        irc_usermsg(irc, "smp: respond with \x02otr smp %s <answer>\x02",
                                u->nick);
                        g_free(question);
                        /* smp stays in EXPECT1 until user responds */
                }
        }
        tlv = otrl_tlv_find(tlvs, OTRL_TLV_SMP1);
        if (tlv) {
                if (nextMsg != OTRL_SMP_EXPECT1) {
                        irc_usermsg(irc, "smp %s: spurious SMP1 received, aborting", u->nick);
                        otrl_message_abort_smp(us, ops, u->bu->ic, context);
                        otrl_sm_state_free(context->smstate);
                } else {
                        irc_usermsg(irc, "smp: initiated by %s"
                                " - respond with \x02otr smp %s <secret>\x02",
                                u->nick, u->nick);
                        /* smp stays in EXPECT1 until user responds */
                }
        }
        tlv = otrl_tlv_find(tlvs, OTRL_TLV_SMP2);
        if (tlv) {
                if (nextMsg != OTRL_SMP_EXPECT2) {
                        irc_usermsg(irc, "smp %s: spurious SMP2 received, aborting", u->nick);
                        otrl_message_abort_smp(us, ops, u->bu->ic, context);
                        otrl_sm_state_free(context->smstate);
                } else {
                        /* SMP2 received, otrl_message_receiving will have sent SMP3 */
                        context->smstate->nextExpected = OTRL_SMP_EXPECT4;
                }
        }
        tlv = otrl_tlv_find(tlvs, OTRL_TLV_SMP3);
        if (tlv) {
                if (nextMsg != OTRL_SMP_EXPECT3) {
                        irc_usermsg(irc, "smp %s: spurious SMP3 received, aborting", u->nick);
                        otrl_message_abort_smp(us, ops, u->bu->ic, context);
                        otrl_sm_state_free(context->smstate);
                } else {
                        /* SMP3 received, otrl_message_receiving will have sent SMP4 */
                        if(context->smstate->sm_prog_state == OTRL_SMP_PROG_SUCCEEDED) {
                                if(context->smstate->received_question) {
                                        irc_usermsg(irc, "smp %s: correct answer, you are trusted",
                                                u->nick);
                                } else {
                                        irc_usermsg(irc, "smp %s: secrets proved equal, fingerprint trusted",
                                                u->nick);
                                }
                        } else {
                                if(context->smstate->received_question) {
                                        irc_usermsg(irc, "smp %s: wrong answer, you are not trusted",
                                                u->nick);
                                } else {
                                        irc_usermsg(irc, "smp %s: secrets did not match, fingerprint not trusted",
                                                u->nick);
                                }
                        }
                        otrl_sm_state_free(context->smstate);
                        /* smp is in back in EXPECT1 */
                }
        }
        tlv = otrl_tlv_find(tlvs, OTRL_TLV_SMP4);
        if (tlv) {
                if (nextMsg != OTRL_SMP_EXPECT4) {
                        irc_usermsg(irc, "smp %s: spurious SMP4 received, aborting", u->nick);
                        otrl_message_abort_smp(us, ops, u->bu->ic, context);
                        otrl_sm_state_free(context->smstate);
                } else {
                        /* SMP4 received, otrl_message_receiving will have set fp trust */
                        if(context->smstate->sm_prog_state == OTRL_SMP_PROG_SUCCEEDED) {
                                irc_usermsg(irc, "smp %s: secrets proved equal, fingerprint trusted",
                                        u->nick);
                        } else {
                                irc_usermsg(irc, "smp %s: secrets did not match, fingerprint not trusted",
                                        u->nick);
                        }
                        otrl_sm_state_free(context->smstate);
                        /* smp is in back in EXPECT1 */
                }
        }
        tlv = otrl_tlv_find(tlvs, OTRL_TLV_SMP_ABORT);
        if (tlv) {
                irc_usermsg(irc, "smp: received abort from %s", u->nick);
                otrl_sm_state_free(context->smstate);
                /* smp is in back in EXPECT1 */
        }
}

/* combined handler for the 'otr smp' and 'otr smpq' commands */
void otr_smp_or_smpq(irc_t *irc, const char *nick, const char *question,
                const char *secret)
{
        irc_user_t *u;
        ConnContext *ctx;

        u = irc_user_by_name(irc, nick);
        if(!u || !u->bu || !u->bu->ic) {
                irc_usermsg(irc, "%s: unknown user", nick);
                return;
        }
        if(!(u->bu->flags & BEE_USER_ONLINE)) {
                irc_usermsg(irc, "%s is offline", nick);
                return;
        }
        
        ctx = otrl_context_find(irc->otr->us, u->bu->handle,
                u->bu->ic->acc->user, u->bu->ic->acc->prpl->name, 0, NULL, NULL, NULL);
        if(!ctx || ctx->msgstate != OTRL_MSGSTATE_ENCRYPTED) {
                irc_usermsg(irc, "smp: otr inactive with %s, try \x02otr connect"
                                " %s\x02", nick, nick);
                return;
        }

        if(ctx->smstate->nextExpected != OTRL_SMP_EXPECT1) {
                log_message(LOGLVL_INFO,
                        "SMP already in phase %d, sending abort before reinitiating",
                        ctx->smstate->nextExpected+1);
                otrl_message_abort_smp(irc->otr->us, &otr_ops, u->bu->ic, ctx);
                otrl_sm_state_free(ctx->smstate);
        }

        if(question) {
                /* this was 'otr smpq', just initiate */
                irc_usermsg(irc, "smp: initiating with %s...", u->nick);
                otrl_message_initiate_smp_q(irc->otr->us, &otr_ops, u->bu->ic, ctx,
                        question, (unsigned char *)secret, strlen(secret));
                /* smp is now in EXPECT2 */
        } else {
                /* this was 'otr smp', initiate or reply */
                /* warning: the following assumes that smstates are cleared whenever an SMP
                   is completed or aborted! */ 
                if(ctx->smstate->secret == NULL) {
                        irc_usermsg(irc, "smp: initiating with %s...", u->nick);
                        otrl_message_initiate_smp(irc->otr->us, &otr_ops,
                                u->bu->ic, ctx, (unsigned char *)secret, strlen(secret));
                        /* smp is now in EXPECT2 */
                } else {
                        /* if we're still in EXPECT1 but smstate is initialized, we must have
                           received the SMP1, so let's issue a response */
                        irc_usermsg(irc, "smp: responding to %s...", u->nick);
                        otrl_message_respond_smp(irc->otr->us, &otr_ops,
                                u->bu->ic, ctx, (unsigned char *)secret, strlen(secret));
                        /* smp is now in EXPECT3 */
                }
        }
}

/* helper to assert that account and protocol names given to ops below always
   match the im_connection passed through as opdata */
struct im_connection *check_imc(void *opdata, const char *accountname,
        const char *protocol)
{
        struct im_connection *ic = (struct im_connection *)opdata;

        if (strcmp(accountname, ic->acc->user) != 0) {
                log_message(LOGLVL_WARNING,
                        "otr: internal account name mismatch: '%s' vs '%s'",
                        accountname, ic->acc->user);
        }
        if (strcmp(protocol, ic->acc->prpl->name) != 0) {
                log_message(LOGLVL_WARNING,
                        "otr: internal protocol name mismatch: '%s' vs '%s'",
                        protocol, ic->acc->prpl->name);
        }
        
        return ic;
}

irc_user_t *peeruser(irc_t *irc, const char *handle, const char *protocol)
{
        GSList *l;
        
        for(l=irc->b->users; l; l = l->next) {
                bee_user_t *bu = l->data;
                struct prpl *prpl;
                if(!bu->ui_data || !bu->ic || !bu->handle)
                        continue;
                prpl = bu->ic->acc->prpl;
                if(strcmp(prpl->name, protocol) == 0
                        && prpl->handle_cmp(bu->handle, handle) == 0) {
                        return bu->ui_data;
                }
        }
        
        return NULL;
}

int hexval(char a)
{
        int x=tolower(a);
        
        if(x>='a' && x<='f')
                x = x - 'a' + 10;
        else if(x>='0' && x<='9')
                x = x - '0';
        else
                return -1;
        
        return x;
}

const char *peernick(irc_t *irc, const char *handle, const char *protocol)
{
        static char fallback[512];
        
        irc_user_t *u = peeruser(irc, handle, protocol);
        if(u) {
                return u->nick;
        } else {
                g_snprintf(fallback, 511, "%s/%s", handle, protocol);
                return fallback;
        }
}

int otr_update_modeflags(irc_t *irc, irc_user_t *u)
{
        return 1;
}

void show_fingerprints(irc_t *irc, ConnContext *ctx)
{
        char human[45];
        Fingerprint *fp;
        const char *trust;
        int count=0;
        
        for(fp=&ctx->fingerprint_root; fp; fp=fp->next) {
                if(!fp->fingerprint)
                        continue;
                count++;
                otrl_privkey_hash_to_human(human, fp->fingerprint);
                if(!fp->trust || fp->trust[0] == '\0') {
                        trust="untrusted";
                } else {
                        trust=fp->trust;
                }
                if(fp == ctx->active_fingerprint) {
                        irc_usermsg(irc, "    \x02%s (%s)\x02", human, trust);
                } else {
                        irc_usermsg(irc, "    %s (%s)", human, trust);
                }
        }
        if(count==0)
                irc_usermsg(irc, "    (none)");
}

Fingerprint *match_fingerprint(irc_t *irc, ConnContext *ctx, const char **args)
{
        Fingerprint *fp, *fp2;
        char human[45];
        char prefix[45], *p;
        int n;
        int i,j;
        
        /* assemble the args into a prefix in standard "human" form */
        n=0;
        p=prefix;
        for(i=0; args[i]; i++) {
                for(j=0; args[i][j]; j++) {
                        char c = toupper(args[i][j]);
                        
                        if(n>=40) {
                                irc_usermsg(irc, "too many fingerprint digits given, expected at most 40");
                                return NULL;
                        }
                        
                        if( (c>='A' && c<='F') || (c>='0' && c<='9') ) {
                                *(p++) = c;
                        } else {
                                irc_usermsg(irc, "invalid hex digit '%c' in block %d", args[i][j], i+1);
                                return NULL;
                        }
                        
                        n++;
                        if(n%8 == 0)
                                *(p++) = ' ';
                }
        }
        *p = '\0';
        
        /* find first fingerprint with the given prefix */
        n = strlen(prefix);
        for(fp=&ctx->fingerprint_root; fp; fp=fp->next) {
                if(!fp->fingerprint)
                        continue;
                otrl_privkey_hash_to_human(human, fp->fingerprint);
                if(!strncmp(prefix, human, n))
                        break;
        }
        if(!fp) {
                irc_usermsg(irc, "%s: no match", prefix);
                return NULL;
        }
        
        /* make sure the match, if any, is unique */
        for(fp2=fp->next; fp2; fp2=fp2->next) {
                if(!fp2->fingerprint)
                        continue;
                otrl_privkey_hash_to_human(human, fp2->fingerprint);
                if(!strncmp(prefix, human, n))
                        break;
        }
        if(fp2) {
                irc_usermsg(irc, "%s: multiple matches", prefix);
                return NULL;
        }
        
        return fp;
}

OtrlPrivKey *match_privkey(irc_t *irc, const char **args)
{
        OtrlPrivKey *k, *k2;
        char human[45];
        char prefix[45], *p;
        int n;
        int i,j;
        
        /* assemble the args into a prefix in standard "human" form */
        n=0;
        p=prefix;
        for(i=0; args[i]; i++) {
                for(j=0; args[i][j]; j++) {
                        char c = toupper(args[i][j]);
                        
                        if(n>=40) {
                                irc_usermsg(irc, "too many fingerprint digits given, expected at most 40");
                                return NULL;
                        }
                        
                        if( (c>='A' && c<='F') || (c>='0' && c<='9') ) {
                                *(p++) = c;
                        } else {
                                irc_usermsg(irc, "invalid hex digit '%c' in block %d", args[i][j], i+1);
                                return NULL;
                        }
                        
                        n++;
                        if(n%8 == 0)
                                *(p++) = ' ';
                }
        }
        *p = '\0';
        
        /* find first key which matches the given prefix */
        n = strlen(prefix);
        for(k=irc->otr->us->privkey_root; k; k=k->next) {
                p = otrl_privkey_fingerprint(irc->otr->us, human, k->accountname, k->protocol);
                if(!p) /* gah! :-P */
                        continue;
                if(!strncmp(prefix, human, n))
                        break;
        }
        if(!k) {
                irc_usermsg(irc, "%s: no match", prefix);
                return NULL;
        }
        
        /* make sure the match, if any, is unique */
        for(k2=k->next; k2; k2=k2->next) {
                p = otrl_privkey_fingerprint(irc->otr->us, human, k2->accountname, k2->protocol);
                if(!p) /* gah! :-P */
                        continue;
                if(!strncmp(prefix, human, n))
                        break;
        }
        if(k2) {
                irc_usermsg(irc, "%s: multiple matches", prefix);
                return NULL;
        }
        
        return k;
}

void show_general_otr_info(irc_t *irc)
{
        ConnContext *ctx;
        OtrlPrivKey *key;
        char human[45];
        kg_t *kg;

        /* list all privkeys (including ones being generated) */
        irc_usermsg(irc, "\x1fprivate keys:\x1f");
        for(key=irc->otr->us->privkey_root; key; key=key->next) {
                const char *hash;
                
                switch(key->pubkey_type) {
                case OTRL_PUBKEY_TYPE_DSA:
                        irc_usermsg(irc, "  %s/%s - DSA", key->accountname, key->protocol);
                        break;
                default:
                        irc_usermsg(irc, "  %s/%s - type %d", key->accountname, key->protocol,
                                key->pubkey_type);
                }

                /* No, it doesn't make much sense to search for the privkey again by
                   account/protocol, but libotr currently doesn't provide a direct routine
                   for hashing a given 'OtrlPrivKey'... */
                hash = otrl_privkey_fingerprint(irc->otr->us, human, key->accountname, key->protocol);
                if(hash) /* should always succeed */
                        irc_usermsg(irc, "    %s", human);
        }
        if(irc->otr->sent_accountname) {
                irc_usermsg(irc, "  %s/%s - DSA", irc->otr->sent_accountname,
                        irc->otr->sent_protocol);
                irc_usermsg(irc, "    (being generated)");
        }
        for(kg=irc->otr->todo; kg; kg=kg->next) {
                irc_usermsg(irc, "  %s/%s - DSA", kg->accountname, kg->protocol);
                irc_usermsg(irc, "    (queued)");
        }
        if(key == irc->otr->us->privkey_root &&
           !irc->otr->sent_accountname &&
           kg == irc->otr->todo)
                irc_usermsg(irc, "  (none)");

        /* list all contexts */
        irc_usermsg(irc, "%s", "");
        irc_usermsg(irc, "\x1f" "connection contexts:\x1f (bold=currently encrypted)");
        for(ctx=irc->otr->us->context_root; ctx; ctx=ctx->next) {\
                irc_user_t *u;
                char *userstring;
                
                u = peeruser(irc, ctx->username, ctx->protocol);
                if(u)
                        userstring = g_strdup_printf("%s/%s/%s (%s)",
                                ctx->username, ctx->protocol, ctx->accountname, u->nick);
                else
                        userstring = g_strdup_printf("%s/%s/%s",
                                ctx->username, ctx->protocol, ctx->accountname);
                
                if(ctx->msgstate == OTRL_MSGSTATE_ENCRYPTED) {
                        irc_usermsg(irc, "  \x02%s\x02", userstring);
                } else {
                        irc_usermsg(irc, "  %s", userstring);
                }
                
                g_free(userstring);
        }
        if(ctx == irc->otr->us->context_root)
                irc_usermsg(irc, "  (none)");
}

void show_otr_context_info(irc_t *irc, ConnContext *ctx)
{
        switch(ctx->otr_offer) {
        case OFFER_NOT:
                irc_usermsg(irc, "  otr offer status: none sent");
                break;
        case OFFER_SENT:
                irc_usermsg(irc, "  otr offer status: awaiting reply");
                break;
        case OFFER_ACCEPTED:
                irc_usermsg(irc, "  otr offer status: accepted our offer");
                break;
        case OFFER_REJECTED:
                irc_usermsg(irc, "  otr offer status: ignored our offer");
                break;
        default:
                irc_usermsg(irc, "  otr offer status: %d", ctx->otr_offer);
        }

        switch(ctx->msgstate) {
        case OTRL_MSGSTATE_PLAINTEXT:
                irc_usermsg(irc, "  connection state: cleartext");
                break;
        case OTRL_MSGSTATE_ENCRYPTED:
                irc_usermsg(irc, "  connection state: encrypted (v%d)", ctx->protocol_version);
                break;
        case OTRL_MSGSTATE_FINISHED:
                irc_usermsg(irc, "  connection state: shut down");
                break;
        default:
                irc_usermsg(irc, "  connection state: %d", ctx->msgstate);
        }

        irc_usermsg(irc, "  fingerprints: (bold=active)");      
        show_fingerprints(irc, ctx);
}

int keygen_in_progress(irc_t *irc, const char *handle, const char *protocol)
{
        kg_t *kg;
        
        if(!irc->otr->sent_accountname || !irc->otr->sent_protocol)
                return 0;

        /* are we currently working on this key? */
        if(!strcmp(handle, irc->otr->sent_accountname) &&
           !strcmp(protocol, irc->otr->sent_protocol))
                return 1;
        
        /* do we have it queued for later? */
        for(kg=irc->otr->todo; kg; kg=kg->next) {
                if(!strcmp(handle, kg->accountname) &&
                   !strcmp(protocol, kg->protocol))
                        return 1;
        }
        
        return 0;
}

void otr_keygen(irc_t *irc, const char *handle, const char *protocol)
{
        /* do nothing if a key for the requested account is already being generated */
        if(keygen_in_progress(irc, handle, protocol))
                return;

        /* see if we already have a keygen child running. if not, start one and put a
           handler on its output. */
        if(!irc->otr->keygen || waitpid(irc->otr->keygen, NULL, WNOHANG)) {
                pid_t p;
                int to[2], from[2];
                FILE *tof, *fromf;
                
                if(pipe(to) < 0 || pipe(from) < 0) {
                        irc_usermsg(irc, "otr keygen: couldn't create pipe: %s", strerror(errno));
                        return;
                }
                
                tof = fdopen(to[1], "w");
                fromf = fdopen(from[0], "r");
                if(!tof || !fromf) {
                        irc_usermsg(irc, "otr keygen: couldn't streamify pipe: %s", strerror(errno));
                        return;
                }
                
                p = fork();
                if(p<0) {
                        irc_usermsg(irc, "otr keygen: couldn't fork: %s", strerror(errno));
                        return;
                }
                
                if(!p) {
                        /* child process */
                        signal(SIGTERM, exit);
                        keygen_child_main(irc->otr->us, to[0], from[1]);
                        exit(0);
                }
                
                irc->otr->keygen = p;
                irc->otr->to = tof;
                irc->otr->from = fromf;
                irc->otr->sent_accountname = NULL;
                irc->otr->sent_protocol = NULL;
                irc->otr->todo = NULL;
                b_input_add(from[0], B_EV_IO_READ, keygen_finish_handler, irc);
        }
        
        /* is the keygen slave currently working? */
        if(irc->otr->sent_accountname) {
                /* enqueue our job for later transmission */
                kg_t **kg = &irc->otr->todo;
                while(*kg)
                        kg=&((*kg)->next);
                *kg = g_new0(kg_t, 1);
                (*kg)->accountname = g_strdup(handle);
                (*kg)->protocol = g_strdup(protocol);
        } else {
                /* send our job over and remember it */
                fprintf(irc->otr->to, "%s\n%s\n", handle, protocol);
                fflush(irc->otr->to);
                irc->otr->sent_accountname = g_strdup(handle);
                irc->otr->sent_protocol = g_strdup(protocol);
        }
}

void keygen_child_main(OtrlUserState us, int infd, int outfd)
{
        FILE *input, *output;
        char filename[128], accountname[512], protocol[512];
        gcry_error_t e;
        int tempfd;
        
        input = fdopen(infd, "r");
        output = fdopen(outfd, "w");
        
        while(!feof(input) && !ferror(input) && !feof(output) && !ferror(output)) {
                myfgets(accountname, 512, input);
                myfgets(protocol, 512, input);
                
                strncpy(filename, "/tmp/bitlbee-XXXXXX", 128);
                tempfd = mkstemp(filename);
                close(tempfd);

                e = otrl_privkey_generate(us, filename, accountname, protocol);
                if(e) {
                        fprintf(output, "\n");  /* this means failure */
                        fprintf(output, "otr keygen: %s\n", gcry_strerror(e));
                        unlink(filename);
                } else {
                        fprintf(output, "%s\n", filename);
                        fprintf(output, "otr keygen for %s/%s complete\n", accountname, protocol);
                }
                fflush(output);
        }
        
        fclose(input);
        fclose(output);
}

gboolean keygen_finish_handler(gpointer data, gint fd, b_input_condition cond)
{
        irc_t *irc = (irc_t *)data;
        char filename[512], msg[512];

        myfgets(filename, 512, irc->otr->from);
        myfgets(msg, 512, irc->otr->from);
        
        irc_usermsg(irc, "%s", msg);
        if(filename[0]) {
                char *kf = g_strdup_printf("%s%s.otr_keys", global.conf->configdir, irc->user->nick);
                char *tmp = g_strdup_printf("%s.new", kf);
                copyfile(filename, tmp);
                unlink(filename);
                rename(tmp,kf);
                otrl_privkey_read(irc->otr->us, kf);
                g_free(kf);
                g_free(tmp);
        }
        
        /* forget this job */
        g_free(irc->otr->sent_accountname);
        g_free(irc->otr->sent_protocol);
        irc->otr->sent_accountname = NULL;
        irc->otr->sent_protocol = NULL;
        
        /* see if there are any more in the queue */
        if(irc->otr->todo) {
                kg_t *p = irc->otr->todo;
                /* send the next one over */
                fprintf(irc->otr->to, "%s\n%s\n", p->accountname, p->protocol);
                fflush(irc->otr->to);
                irc->otr->sent_accountname = p->accountname;
                irc->otr->sent_protocol = p->protocol;
                irc->otr->todo = p->next;
                g_free(p);
                return TRUE;   /* keep watching */
        } else {
                /* okay, the slave is idle now, so kill him */
                fclose(irc->otr->from);
                fclose(irc->otr->to);
                irc->otr->from = irc->otr->to = NULL;
                kill(irc->otr->keygen, SIGTERM);
                waitpid(irc->otr->keygen, NULL, 0);
                irc->otr->keygen = 0;
                return FALSE;  /* unregister ourselves */
        }
}

void copyfile(const char *a, const char *b)
{
        int fda, fdb;
        int n;
        char buf[1024];
        
        fda = open(a, O_RDONLY);
        fdb = open(b, O_WRONLY | O_CREAT | O_TRUNC, 0600);
        
        while((n=read(fda, buf, 1024)) > 0)
                write(fdb, buf, n);
        
        close(fda);
        close(fdb);     
}

void myfgets(char *s, int size, FILE *stream)
{
        if(!fgets(s, size, stream)) {
                s[0] = '\0';
        } else {
                int n = strlen(s);
                if(n>0 && s[n-1] == '\n')
                        s[n-1] = '\0';
        }
}

void yes_keygen(void *data)
{
        account_t *acc = (account_t *)data;
        irc_t *irc = acc->bee->ui_data;
        
        if(keygen_in_progress(irc, acc->user, acc->prpl->name)) {
                irc_usermsg(irc, "keygen for %s/%s already in progress",
                        acc->user, acc->prpl->name);
        } else {
                irc_usermsg(irc, "starting background keygen for %s/%s",
                        acc->user, acc->prpl->name);
                irc_usermsg(irc, "you will be notified when it completes");
                otr_keygen(irc, acc->user, acc->prpl->name);
        }
}