source: storage_xml.c @ 0b9daac

/********************************************************************\
  * BitlBee -- An IRC to other IM-networks gateway                     *
  *                                                                    *
  * Copyright 2002-2012 Wilmer van der Gaast and others                *
  \********************************************************************/

/* Storage backend that uses an XMLish format for all data. */

/*
  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., 51 Franklin St.,
  Fifth Floor, Boston, MA  02110-1301  USA
*/

#define BITLBEE_CORE
#include "bitlbee.h"
#include "lib/base64.h"
#include "lib/arc.h"
#include "lib/md5.h"
#include "lib/xmltree.h"

#include <glib/gstdio.h>

typedef enum {
        XML_PASS_CHECK_ONLY = -1,
        XML_PASS_UNKNOWN = 0,
        XML_PASS_WRONG,
        XML_PASS_OK
} xml_pass_st;

/* To make it easier later when extending the format: */
#define XML_FORMAT_VERSION "1"

struct xml_parsedata {
        irc_t *irc;
        char given_nick[MAX_NICK_LENGTH + 1];
        char *given_pass;
};

static void xml_init(void)
{
        if (g_access(global.conf->configdir, F_OK) != 0) {
                log_message(LOGLVL_WARNING,
                            "The configuration directory `%s' does not exist. Configuration won't be saved.",
                            global.conf->configdir);
        } else if (g_access(global.conf->configdir, F_OK) != 0 ||
                   g_access(global.conf->configdir, W_OK) != 0) {
                log_message(LOGLVL_WARNING, "Permission problem: Can't read/write from/to `%s'.",
                            global.conf->configdir);
        }
}

static void handle_settings(struct xt_node *node, set_t **head)
{
        struct xt_node *c;

        for (c = node->children; (c = xt_find_node(c, "setting")); c = c->next) {
                char *name = xt_find_attr(c, "name");

                if (!name) {
                        continue;
                }

                if (strcmp(node->name, "account") == 0) {
                        set_t *s = set_find(head, name);
                        if (s && (s->flags & ACC_SET_ONLINE_ONLY)) {
                                continue; /* U can't touch this! */
                        }
                }
                set_setstr(head, name, c->text);
        }
}

static xt_status handle_account(struct xt_node *node, gpointer data)
{
        struct xml_parsedata *xd = data;
        char *protocol, *handle, *server, *password = NULL, *autoconnect, *tag;
        char *pass_b64 = NULL;
        unsigned char *pass_cr = NULL;
        int pass_len, local = 0;
        struct prpl *prpl = NULL;
        account_t *acc;
        struct xt_node *c;

        handle = xt_find_attr(node, "handle");
        pass_b64 = xt_find_attr(node, "password");
        server = xt_find_attr(node, "server");
        autoconnect = xt_find_attr(node, "autoconnect");
        tag = xt_find_attr(node, "tag");

        protocol = xt_find_attr(node, "protocol");
        if (protocol) {
                prpl = find_protocol(protocol);
                local = protocol_account_islocal(protocol);
        }

        if (!handle || !pass_b64 || !protocol || !prpl) {
                return XT_ABORT;
        } else if ((pass_len = base64_decode(pass_b64, (unsigned char **) &pass_cr)) &&
                   arc_decode(pass_cr, pass_len, &password, xd->given_pass) >= 0) {
                acc = account_add(xd->irc->b, prpl, handle, password);
                if (server) {
                        set_setstr(&acc->set, "server", server);
                }
                if (autoconnect) {
                        set_setstr(&acc->set, "auto_connect", autoconnect);
                }
                if (tag) {
                        set_setstr(&acc->set, "tag", tag);
                }
                if (local) {
                        acc->flags |= ACC_FLAG_LOCAL;
                }
        } else {
                return XT_ABORT;
        }

        g_free(pass_cr);
        g_free(password);

        handle_settings(node, &acc->set);

        for (c = node->children; (c = xt_find_node(c, "buddy")); c = c->next) {
                char *handle, *nick;

                handle = xt_find_attr(c, "handle");
                nick = xt_find_attr(c, "nick");

                if (handle && nick) {
                        nick_set_raw(acc, handle, nick);
                } else {
                        return XT_ABORT;
                }
        }
        return XT_HANDLED;
}

static xt_status handle_channel(struct xt_node *node, gpointer data)
{
        struct xml_parsedata *xd = data;
        irc_channel_t *ic;
        char *name, *type;

        name = xt_find_attr(node, "name");
        type = xt_find_attr(node, "type");

        if (!name || !type) {
                return XT_ABORT;
        }

        /* The channel may exist already, for example if it's &bitlbee.
           Also, it's possible that the user just reconnected and the
           IRC client already rejoined all channels it was in. They
           should still get the right settings. */
        if ((ic = irc_channel_by_name(xd->irc, name)) ||
            (ic = irc_channel_new(xd->irc, name))) {
                set_setstr(&ic->set, "type", type);
        }

        handle_settings(node, &ic->set);

        return XT_HANDLED;
}

static const struct xt_handler_entry handlers[] = {
        { "account", "user", handle_account, },
        { "channel", "user", handle_channel, },
        { NULL,      NULL,   NULL, },
};

static storage_status_t xml_load_real(irc_t *irc, const char *my_nick, const char *password, xml_pass_st action)
{
        struct xml_parsedata xd[1];
        char *fn, buf[2048];
        int fd, st;
        struct xt_parser *xp = NULL;
        struct xt_node *node;
        storage_status_t ret = STORAGE_OTHER_ERROR;

        xd->irc = irc;
        strncpy(xd->given_nick, my_nick, MAX_NICK_LENGTH);
        xd->given_nick[MAX_NICK_LENGTH] = '\0';
        nick_lc(NULL, xd->given_nick);
        xd->given_pass = (char *) password;

        fn = g_strconcat(global.conf->configdir, xd->given_nick, ".xml", NULL);
        if ((fd = open(fn, O_RDONLY)) < 0) {
                ret = STORAGE_NO_SUCH_USER;
                goto error;
        }

        xp = xt_new(handlers, xd);
        while ((st = read(fd, buf, sizeof(buf))) > 0) {
                st = xt_feed(xp, buf, st);
                if (st != 1) {
                        break;
                }
        }
        close(fd);
        if (st != 0) {
                goto error;
        }

        node = xp->root;
        if (node == NULL || node->next != NULL || strcmp(node->name, "user") != 0) {
                goto error;
        }

        {
                char *nick = xt_find_attr(node, "nick");
                char *pass = xt_find_attr(node, "password");

                if (!nick || !pass) {
                        goto error;
                } else if ((st = md5_verify_password(xd->given_pass, pass)) != 0) {
                        ret = STORAGE_INVALID_PASSWORD;
                        goto error;
                }
        }

        if (action == XML_PASS_CHECK_ONLY) {
                ret = STORAGE_OK;
                goto error;
        }

        /* DO NOT call xt_handle() before verifying the password! */
        if (xt_handle(xp, NULL, 1) == XT_HANDLED) {
                ret = STORAGE_OK;
        }

        handle_settings(node, &xd->irc->b->set);

error:
        xt_free(xp);
        g_free(fn);
        return ret;
}

static storage_status_t xml_load(irc_t *irc, const char *password)
{
        return xml_load_real(irc, irc->user->nick, password, XML_PASS_UNKNOWN);
}

static storage_status_t xml_check_pass(const char *my_nick, const char *password)
{
        return xml_load_real(NULL, my_nick, password, XML_PASS_CHECK_ONLY);
}


static gboolean xml_generate_nick(gpointer key, gpointer value, gpointer data);
static void xml_generate_settings(struct xt_node *cur, set_t **head);

struct xt_node *xml_generate(irc_t *irc)
{
        char *pass_buf = NULL;
        account_t *acc;
        md5_byte_t pass_md5[21];
        md5_state_t md5_state;
        GSList *l;
        struct xt_node *root, *cur;

        /* Generate a salted md5sum of the password. Use 5 bytes for the salt
           (to prevent dictionary lookups of passwords) to end up with a 21-
           byte password hash, more convenient for base64 encoding. */
        random_bytes(pass_md5 + 16, 5);
        md5_init(&md5_state);
        md5_append(&md5_state, (md5_byte_t *) irc->password, strlen(irc->password));
        md5_append(&md5_state, pass_md5 + 16, 5);   /* Add the salt. */
        md5_finish(&md5_state, pass_md5);
        /* Save the hash in base64-encoded form. */
        pass_buf = base64_encode(pass_md5, 21);

        root = cur = xt_new_node("user", NULL, NULL);
        xt_add_attr(cur, "nick", irc->user->nick);
        xt_add_attr(cur, "password", pass_buf);
        xt_add_attr(cur, "version", XML_FORMAT_VERSION);

        g_free(pass_buf);

        xml_generate_settings(cur, &irc->b->set);

        for (acc = irc->b->accounts; acc; acc = acc->next) {
                unsigned char *pass_cr;
                char *pass_b64;
                int pass_len;

                pass_len = arc_encode(acc->pass, strlen(acc->pass), (unsigned char **) &pass_cr, irc->password, 12);
                pass_b64 = base64_encode(pass_cr, pass_len);
                g_free(pass_cr);

                cur = xt_new_node("account", NULL, NULL);
                xt_add_attr(cur, "protocol", acc->prpl->name);
                xt_add_attr(cur, "handle", acc->user);
                xt_add_attr(cur, "password", pass_b64);
                xt_add_attr(cur, "autoconnect", acc->auto_connect ? "true" : "false");
                xt_add_attr(cur, "tag", acc->tag);
                if (acc->server && acc->server[0]) {
                        xt_add_attr(cur, "server", acc->server);
                }

                g_free(pass_b64);

                /* This probably looks pretty strange. g_hash_table_foreach
                   is quite a PITA already (but it can't get much better in
                   C without using #define, I'm afraid), and it
                   doesn't seem to be possible to abort the foreach on write
                   errors, so instead let's use the _find function and
                   return TRUE on write errors. Which means, if we found
                   something, there was an error. :-) */
                g_hash_table_find(acc->nicks, xml_generate_nick, cur);

                xml_generate_settings(cur, &acc->set);

                xt_add_child(root, cur);
        }

        for (l = irc->channels; l; l = l->next) {
                irc_channel_t *ic = l->data;

                if (ic->flags & IRC_CHANNEL_TEMP) {
                        continue;
                }

                cur = xt_new_node("channel", NULL, NULL);
                xt_add_attr(cur, "name", ic->name);
                xt_add_attr(cur, "type", set_getstr(&ic->set, "type"));

                xml_generate_settings(cur, &ic->set);

                xt_add_child(root, cur);
        }

        return root;
}

static gboolean xml_generate_nick(gpointer key, gpointer value, gpointer data)
{
        struct xt_node *node = xt_new_node("buddy", NULL, NULL);

        xt_add_attr(node, "handle", key);
        xt_add_attr(node, "nick", value);
        xt_add_child((struct xt_node *) data, node);

        return FALSE;
}

static void xml_generate_settings(struct xt_node *cur, set_t **head)
{
        set_t *set;

        for (set = *head; set; set = set->next) {
                if (set->value && !(set->flags & SET_NOSAVE)) {
                        struct xt_node *xset;
                        xt_add_child(cur, xset = xt_new_node("setting", set->value, NULL));
                        xt_add_attr(xset, "name", set->key);
                }
        }
}

static storage_status_t xml_save(irc_t *irc, int overwrite)
{
        storage_status_t ret = STORAGE_OK;
        char path[512], *path2 = NULL, *xml = NULL;
        struct xt_node *tree = NULL;
        size_t len;
        int fd;

        path2 = g_strdup(irc->user->nick);
        nick_lc(NULL, path2);
        g_snprintf(path, sizeof(path) - 20, "%s%s%s", global.conf->configdir, path2, ".xml");
        g_free(path2);

        if (!overwrite && g_access(path, F_OK) == 0) {
                return STORAGE_ALREADY_EXISTS;
        }

        strcat(path, ".XXXXXX");
        if ((fd = mkstemp(path)) < 0) {
                irc_rootmsg(irc, "Error while opening configuration file.");
                return STORAGE_OTHER_ERROR;
        }

        tree = xml_generate(irc);
        xml = xt_to_string_i(tree);
        len = strlen(xml);
        if (write(fd, xml, len) != len ||
            fsync(fd) != 0 ||   /* #559 */
            close(fd) != 0) {
                goto error;
        }

        path2 = g_strndup(path, strlen(path) - 7);
        if (rename(path, path2) != 0) {
                g_free(path2);
                goto error;
        }
        g_free(path2);

        goto finish;

error:
        irc_rootmsg(irc, "Write error. Disk full?");
        ret = STORAGE_OTHER_ERROR;

finish:
        close(fd);
        unlink(path);
        g_free(xml);
        xt_free_node(tree);

        return ret;
}


static storage_status_t xml_remove(const char *nick, const char *password)
{
        char s[512], *lc;
        storage_status_t status;

        status = xml_check_pass(nick, password);
        if (status != STORAGE_OK) {
                return status;
        }

        lc = g_strdup(nick);
        nick_lc(NULL, lc);
        g_snprintf(s, 511, "%s%s%s", global.conf->configdir, lc, ".xml");
        g_free(lc);

        if (unlink(s) == -1) {
                return STORAGE_OTHER_ERROR;
        }

        return STORAGE_OK;
}

storage_t storage_xml = {
        .name = "xml",
        .init = xml_init,
        .check_pass = xml_check_pass,
        .remove = xml_remove,
        .load = xml_load,
        .save = xml_save
};