Sylpheed

/*

 * Sylpheed -- a GTK+ based, lightweight, and fast e-mail client

 * Copyright (C) 1999-2004 Hiroyuki Yamamoto

 *

 * 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

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

 */

#ifdef HAVE_CONFIG_H

#  include "config.h"

#endif

#include "defs.h"

#include <glib.h>

#include <glib/gi18n.h>

#include <stdio.h>

#include <string.h>

#include <stdarg.h>

#include <ctype.h>

#include <unistd.h>

#include <time.h>

#include <errno.h>

#include "pop.h"

#include "md5.h"

#include "prefs_account.h"

#include "utils.h"

#include "recv.h"

static gint pop3_greeting_recv                (Pop3Session *session,

                                         const gchar *msg);

static gint pop3_getauth_user_send        (Pop3Session *session);

static gint pop3_getauth_pass_send        (Pop3Session *session);

static gint pop3_getauth_apop_send        (Pop3Session *session);

#if USE_SSL

static gint pop3_stls_send                (Pop3Session *session);

static gint pop3_stls_recv                (Pop3Session *session);

#endif

static gint pop3_getrange_stat_send        (Pop3Session *session);

static gint pop3_getrange_stat_recv        (Pop3Session *session,

                                         const gchar *msg);

static gint pop3_getrange_last_send        (Pop3Session *session);

static gint pop3_getrange_last_recv        (Pop3Session *session,

                                         const gchar *msg);

static gint pop3_getrange_uidl_send        (Pop3Session *session);

static gint pop3_getrange_uidl_recv        (Pop3Session *session,

                                         const gchar *data,

                                         guint        len);

static gint pop3_getsize_list_send        (Pop3Session *session);

static gint pop3_getsize_list_recv        (Pop3Session *session,

                                         const gchar *data,

                                         guint        len);

static gint pop3_retr_send                (Pop3Session *session);

static gint pop3_retr_recv                (Pop3Session *session,

                                         const gchar *data,

                                         guint        len);

static gint pop3_delete_send                (Pop3Session *session);

static gint pop3_delete_recv                (Pop3Session *session);

static gint pop3_logout_send                (Pop3Session *session);

static void pop3_gen_send                (Pop3Session        *session,

                                         const gchar        *format, ...);

static void pop3_session_destroy        (Session        *session);

static gint pop3_write_msg_to_file        (const gchar        *file,

                                         const gchar        *data,

                                         guint                 len);

static Pop3State pop3_lookup_next        (Pop3Session        *session);

static Pop3ErrorValue pop3_ok                (Pop3Session        *session,

                                         const gchar        *msg);

static gint pop3_session_recv_msg                (Session        *session,

                                                 const gchar        *msg);

static gint pop3_session_recv_data_finished        (Session        *session,

                                                 guchar                *data,

                                                 guint                 len);

static gint pop3_greeting_recv(Pop3Session *session, const gchar *msg)

{

        session->state = POP3_GREETING;

        session->greeting = g_strdup(msg);

        return PS_SUCCESS;

}

#if USE_SSL

static gint pop3_stls_send(Pop3Session *session)

{

        session->state = POP3_STLS;

        pop3_gen_send(session, "STLS");

        return PS_SUCCESS;

}

static gint pop3_stls_recv(Pop3Session *session)

{

        if (session_start_tls(SESSION(session)) < 0) {

                session->error_val = PS_SOCKET;

                return -1;

        }

        return PS_SUCCESS;

}

#endif /* USE_SSL */

static gint pop3_getauth_user_send(Pop3Session *session)

{

        g_return_val_if_fail(session->user != NULL, -1);

        session->state = POP3_GETAUTH_USER;

        pop3_gen_send(session, "USER %s", session->user);

        return PS_SUCCESS;

}

static gint pop3_getauth_pass_send(Pop3Session *session)

{

        g_return_val_if_fail(session->pass != NULL, -1);

        session->state = POP3_GETAUTH_PASS;

        pop3_gen_send(session, "PASS %s", session->pass);

        return PS_SUCCESS;

}

static gint pop3_getauth_apop_send(Pop3Session *session)

{

        gchar *start, *end;

        gchar *apop_str;

        gchar md5sum[33];

        g_return_val_if_fail(session->user != NULL, -1);

        g_return_val_if_fail(session->pass != NULL, -1);

        session->state = POP3_GETAUTH_APOP;

        if ((start = strchr(session->greeting, '<')) == NULL) {

                log_warning(_("Required APOP timestamp not found "

                              "in greeting\n"));

                session->error_val = PS_PROTOCOL;

                return -1;

        }

        if ((end = strchr(start, '>')) == NULL || end == start + 1) {

                log_warning(_("Timestamp syntax error in greeting\n"));

                session->error_val = PS_PROTOCOL;

                return -1;

        }

        *(end + 1) = '\0';

        apop_str = g_strconcat(start, session->pass, NULL);

        md5_hex_digest(md5sum, apop_str);

        g_free(apop_str);

        pop3_gen_send(session, "APOP %s %s", session->user, md5sum);

        return PS_SUCCESS;

}

static gint pop3_getrange_stat_send(Pop3Session *session)

{

        session->state = POP3_GETRANGE_STAT;

        pop3_gen_send(session, "STAT");

        return PS_SUCCESS;

}

static gint pop3_getrange_stat_recv(Pop3Session *session, const gchar *msg)

{

        if (sscanf(msg, "%d %d", &session->count, &session->total_bytes) != 2) {

                log_warning(_("POP3 protocol error\n"));

                session->error_val = PS_PROTOCOL;

                return -1;

        } else {

                if (session->count == 0) {

                        session->uidl_is_valid = TRUE;

                } else {

                        session->msg = g_new0(Pop3MsgInfo, session->count + 1);

                        session->cur_msg = 1;

                }

        }

        return PS_SUCCESS;

}

static gint pop3_getrange_last_send(Pop3Session *session)

{

        session->state = POP3_GETRANGE_LAST;

        pop3_gen_send(session, "LAST");

        return PS_SUCCESS;

}

static gint pop3_getrange_last_recv(Pop3Session *session, const gchar *msg)

{

        gint last;

        if (sscanf(msg, "%d", &last) == 0) {

                log_warning(_("POP3 protocol error\n"));

                session->error_val = PS_PROTOCOL;

                return -1;

        } else {

                if (session->count > last) {

                        session->new_msg_exist = TRUE;

                        session->cur_msg = last + 1;

                } else

                        session->cur_msg = 0;

        }

        return PS_SUCCESS;

}

static gint pop3_getrange_uidl_send(Pop3Session *session)

{

        session->state = POP3_GETRANGE_UIDL;

        pop3_gen_send(session, "UIDL");

        return PS_SUCCESS;

}

static gint pop3_getrange_uidl_recv(Pop3Session *session, const gchar *data,

                                    guint len)

{

        gchar id[IDLEN + 1];

        gchar buf[POPBUFSIZE];

        gint buf_len;

        gint num;

        time_t recv_time;

        const gchar *p = data;

        const gchar *lastp = data + len;

        const gchar *newline;

        while (p < lastp) {

                if ((newline = memchr(p, '\r', lastp - p)) == NULL)

                        return -1;

                buf_len = MIN(newline - p, sizeof(buf) - 1);

                memcpy(buf, p, buf_len);

                buf[buf_len] = '\0';

                p = newline + 1;

                if (p < lastp && *p == '\n') p++;

                if (sscanf(buf, "%d %" Xstr(IDLEN) "s", &num, id) != 2 ||

                    num <= 0 || num > session->count) {

                        log_warning(_("invalid UIDL response: %s\n"), buf);

                        continue;

                }

                session->msg[num].uidl = g_strdup(id);

                recv_time = (time_t)g_hash_table_lookup(session->uidl_table, id);

                session->msg[num].recv_time = recv_time;

                if (!session->ac_prefs->getall && recv_time != RECV_TIME_NONE)

                        session->msg[num].received = TRUE;

                if (!session->new_msg_exist &&

                    (session->ac_prefs->getall || recv_time == RECV_TIME_NONE ||

                     session->ac_prefs->rmmail)) {

                        session->cur_msg = num;

                        session->new_msg_exist = TRUE;

                }

        }

        session->uidl_is_valid = TRUE;

        return PS_SUCCESS;

}

static gint pop3_getsize_list_send(Pop3Session *session)

{

        session->state = POP3_GETSIZE_LIST;

        pop3_gen_send(session, "LIST");

        return PS_SUCCESS;

}

static gint pop3_getsize_list_recv(Pop3Session *session, const gchar *data,

                                   guint len)

{

        gchar buf[POPBUFSIZE];

        gint buf_len;

        guint num, size;

        const gchar *p = data;

        const gchar *lastp = data + len;

        const gchar *newline;

        while (p < lastp) {

                if ((newline = memchr(p, '\r', lastp - p)) == NULL)

                        return -1;

                buf_len = MIN(newline - p, sizeof(buf) - 1);

                memcpy(buf, p, buf_len);

                buf[buf_len] = '\0';

                p = newline + 1;

                if (p < lastp && *p == '\n') p++;

                if (sscanf(buf, "%u %u", &num, &size) != 2) {

                        session->error_val = PS_PROTOCOL;

                        return -1;

                }

                if (num > 0 && num <= session->count)

                        session->msg[num].size = size;

                if (num > 0 && num < session->cur_msg)

                        session->cur_total_bytes += size;

        }

        return PS_SUCCESS;

}

static gint pop3_retr_send(Pop3Session *session)

{

        session->state = POP3_RETR;

        pop3_gen_send(session, "RETR %d", session->cur_msg);

        return PS_SUCCESS;

}

static gint pop3_retr_recv(Pop3Session *session, const gchar *data, guint len)

{

        gchar *file;

        gint drop_ok;

        file = get_tmp_file();

        if (pop3_write_msg_to_file(file, data, len) < 0) {

                g_free(file);

                session->error_val = PS_IOERR;

                return -1;

        }

        drop_ok = session->drop_message(session, file);

        unlink(file);

        g_free(file);

        if (drop_ok < 0) {

                session->error_val = PS_IOERR;

                return -1;

        }

        session->cur_total_bytes += session->msg[session->cur_msg].size;

        session->cur_total_recv_bytes += session->msg[session->cur_msg].size;

        session->cur_total_num++;

        session->msg[session->cur_msg].received = TRUE;

        session->msg[session->cur_msg].recv_time =

                drop_ok == DROP_DONT_RECEIVE ? RECV_TIME_KEEP

                        : drop_ok == DROP_DELETE ? RECV_TIME_DELETE

                        : session->current_time;

        return PS_SUCCESS;

}

static gint pop3_delete_send(Pop3Session *session)

{

        session->state = POP3_DELETE;

        pop3_gen_send(session, "DELE %d", session->cur_msg);

        return PS_SUCCESS;

}

static gint pop3_delete_recv(Pop3Session *session)

{

        session->msg[session->cur_msg].deleted = TRUE;

        return PS_SUCCESS;

}

static gint pop3_logout_send(Pop3Session *session)

{

        session->state = POP3_LOGOUT;

        pop3_gen_send(session, "QUIT");

        return PS_SUCCESS;

}

static void pop3_gen_send(Pop3Session *session, const gchar *format, ...)

{

        gchar buf[POPBUFSIZE + 1];

        va_list args;

        va_start(args, format);

        g_vsnprintf(buf, sizeof(buf) - 2, format, args);

        va_end(args);

        if (!g_ascii_strncasecmp(buf, "PASS ", 5))

                log_print("POP3> PASS ********\n");

        else

                log_print("POP3> %s\n", buf);

        session_send_msg(SESSION(session), SESSION_MSG_NORMAL, buf);

}

Session *pop3_session_new(PrefsAccount *account)

{

        Pop3Session *session;

        g_return_val_if_fail(account != NULL, NULL);

        session = g_new0(Pop3Session, 1);

        session_init(SESSION(session));

        SESSION(session)->type = SESSION_POP3;

        SESSION(session)->recv_msg = pop3_session_recv_msg;

        SESSION(session)->recv_data_finished = pop3_session_recv_data_finished;

        SESSION(session)->send_data_finished = NULL;

        SESSION(session)->destroy = pop3_session_destroy;

        session->state = POP3_READY;

        session->ac_prefs = account;

        session->uidl_table = pop3_get_uidl_table(account);

        session->current_time = time(NULL);

        session->error_val = PS_SUCCESS;

        session->error_msg = NULL;

        return SESSION(session);

}

static void pop3_session_destroy(Session *session)

{

        Pop3Session *pop3_session = POP3_SESSION(session);

        gint n;

        g_return_if_fail(session != NULL);

        for (n = 1; n <= pop3_session->count; n++)

                g_free(pop3_session->msg[n].uidl);

        g_free(pop3_session->msg);

        if (pop3_session->uidl_table) {

                hash_free_strings(pop3_session->uidl_table);

                g_hash_table_destroy(pop3_session->uidl_table);

        }

        g_free(pop3_session->greeting);

        g_free(pop3_session->user);

        g_free(pop3_session->pass);

        g_free(pop3_session->error_msg);

}

GHashTable *pop3_get_uidl_table(PrefsAccount *ac_prefs)

{

        GHashTable *table;

        gchar *path;

        FILE *fp;

        gchar buf[POPBUFSIZE];

        gchar uidl[POPBUFSIZE];

        time_t recv_time;

        time_t now;

        table = g_hash_table_new(g_str_hash, g_str_equal);

        path = g_strconcat(get_rc_dir(), G_DIR_SEPARATOR_S,

                           UIDL_DIR, G_DIR_SEPARATOR_S, ac_prefs->recv_server,

                           "-", ac_prefs->userid, NULL);

        if ((fp = fopen(path, "rb")) == NULL) {

                if (ENOENT != errno) FILE_OP_ERROR(path, "fopen");

                g_free(path);

                return table;

        }

        g_free(path);

        now = time(NULL);

        while (fgets(buf, sizeof(buf), fp) != NULL) {

                strretchomp(buf);

                recv_time = RECV_TIME_NONE;

                if (sscanf(buf, "%s\t%ld", uidl, &recv_time) != 2) {

                        if (sscanf(buf, "%s", uidl) != 1)

                                continue;

                        else

                                recv_time = now;

                }

                if (recv_time == RECV_TIME_NONE)

                        recv_time = RECV_TIME_RECEIVED;

                g_hash_table_insert(table, g_strdup(uidl),

                                    GINT_TO_POINTER(recv_time));

        }

        fclose(fp);

        return table;

}

gint pop3_write_uidl_list(Pop3Session *session)

{

        gchar *path;

        FILE *fp;

        Pop3MsgInfo *msg;

        gint n;

        if (!session->uidl_is_valid) return 0;

        path = g_strconcat(get_rc_dir(), G_DIR_SEPARATOR_S,

                           "uidl", G_DIR_SEPARATOR_S,

                           session->ac_prefs->recv_server,

                           "-", session->ac_prefs->userid, NULL);

        if ((fp = fopen(path, "wb")) == NULL) {

                FILE_OP_ERROR(path, "fopen");

                g_free(path);

                return -1;

        }

        for (n = 1; n <= session->count; n++) {

                msg = &session->msg[n];

                if (msg->uidl && msg->received && !msg->deleted)

                        fprintf(fp, "%s\t%ld\n", msg->uidl, msg->recv_time);

        }

        if (fclose(fp) == EOF) FILE_OP_ERROR(path, "fclose");

        g_free(path);

        return 0;

}

static gint pop3_write_msg_to_file(const gchar *file, const gchar *data,

                                   guint len)

{

        FILE *fp;

        const gchar *prev, *cur;

        g_return_val_if_fail(file != NULL, -1);

        if ((fp = fopen(file, "wb")) == NULL) {

                FILE_OP_ERROR(file, "fopen");

                return -1;

        }

        if (change_file_mode_rw(fp, file) < 0)

                FILE_OP_ERROR(file, "chmod");

        /* +------------------+----------------+--------------------------+ *

         * ^data              ^prev            ^cur             data+len-1^ */

        prev = data;

        while ((cur = (gchar *)my_memmem(prev, len - (prev - data), "\r\n", 2))

               != NULL) {

                if ((cur > prev && fwrite(prev, cur - prev, 1, fp) < 1) ||

                    fputc('\n', fp) == EOF) {

                        FILE_OP_ERROR(file, "fwrite");

                        g_warning("can't write to file: %s\n", file);

                        fclose(fp);

                        unlink(file);

                        return -1;

                }

                if (cur == data + len - 1) {

                        prev = cur + 1;

                        break;

                }

                if (*(cur + 1) == '\n')

                        prev = cur + 2;

                else

                        prev = cur + 1;

                if (prev - data < len - 1 && *prev == '.' && *(prev + 1) == '.')

                        prev++;

                if (prev - data >= len)

                        break;

        }

        if (prev - data < len &&

            fwrite(prev, len - (prev - data), 1, fp) < 1) {

                FILE_OP_ERROR(file, "fwrite");

                g_warning("can't write to file: %s\n", file);

                fclose(fp);

                unlink(file);

                return -1;

        }

        if (data[len - 1] != '\r' && data[len - 1] != '\n') {

                if (fputc('\n', fp) == EOF) {

                        FILE_OP_ERROR(file, "fputc");

                        g_warning("can't write to file: %s\n", file);

                        fclose(fp);

                        unlink(file);

                        return -1;

                }

        }

        if (fclose(fp) == EOF) {

                FILE_OP_ERROR(file, "fclose");

                unlink(file);

                return -1;

        }

        return 0;

}

static Pop3State pop3_lookup_next(Pop3Session *session)

{

        Pop3MsgInfo *msg;

        PrefsAccount *ac = session->ac_prefs;

        gint size;

        gboolean size_limit_over;

        for (;;) {

                msg = &session->msg[session->cur_msg];

                size = msg->size;

                size_limit_over =

                    (ac->enable_size_limit &&

                     ac->size_limit > 0 &&

                     size > ac->size_limit * 1024);

                if (msg->recv_time == RECV_TIME_DELETE ||

                    (ac->rmmail &&

                     msg->recv_time != RECV_TIME_NONE &&

                     msg->recv_time != RECV_TIME_KEEP &&

                     session->current_time - msg->recv_time >=

                     ac->msg_leave_time * 24 * 60 * 60)) {

                        log_print(_("POP3: Deleting expired message %d\n"),

                                  session->cur_msg);

                        pop3_delete_send(session);

                        return POP3_DELETE;

                }

                if (size_limit_over)

                        log_print

                                (_("POP3: Skipping message %d (%d bytes)\n"),

                                  session->cur_msg, size);

                if (size == 0 || msg->received || size_limit_over) {

                        session->cur_total_bytes += size;

                        if (session->cur_msg == session->count) {

                                pop3_logout_send(session);

                                return POP3_LOGOUT;

                        } else

                                session->cur_msg++;

                } else

                        break;

        }

        pop3_retr_send(session);

        return POP3_RETR;

}

static Pop3ErrorValue pop3_ok(Pop3Session *session, const gchar *msg)

{

        Pop3ErrorValue ok;

        log_print("POP3< %s\n", msg);

        if (!strncmp(msg, "+OK", 3))

                ok = PS_SUCCESS;

        else if (!strncmp(msg, "-ERR", 4)) {

                if (strstr(msg + 4, "lock") ||

                    strstr(msg + 4, "Lock") ||

                    strstr(msg + 4, "LOCK") ||

                    strstr(msg + 4, "wait")) {

                        log_warning(_("mailbox is locked\n"));

                        ok = PS_LOCKBUSY;

                } else if (strcasestr(msg + 4, "timeout")) {

                        log_warning(_("session timeout\n"));

                        ok = PS_ERROR;

                } else {

                        switch (session->state) {

#if USE_SSL

                        case POP3_STLS:

                                log_warning(_("can't start TLS session\n"));

                                ok = PS_ERROR;

                                break;

#endif

                        case POP3_GETAUTH_USER:

                        case POP3_GETAUTH_PASS:

                        case POP3_GETAUTH_APOP:

                                log_warning(_("error occurred on authentication\n"));

                                ok = PS_AUTHFAIL;

                                break;

                        case POP3_GETRANGE_LAST:

                        case POP3_GETRANGE_UIDL:

                                log_warning(_("command not supported\n"));

                                ok = PS_NOTSUPPORTED;

                                break;

                        default:

                                log_warning(_("error occurred on POP3 session\n"));

                                ok = PS_ERROR;

                        }

                }

                g_free(session->error_msg);

                session->error_msg = g_strdup(msg);

                fprintf(stderr, "POP3: %s\n", msg);

        } else

                ok = PS_PROTOCOL;

        session->error_val = ok;

        return ok;

}

static gint pop3_session_recv_msg(Session *session, const gchar *msg)

{

        Pop3Session *pop3_session = POP3_SESSION(session);

        Pop3ErrorValue val = PS_SUCCESS;

        const guchar *body;

        body = msg;

        if (pop3_session->state != POP3_GETRANGE_UIDL_RECV &&

            pop3_session->state != POP3_GETSIZE_LIST_RECV) {

                val = pop3_ok(pop3_session, msg);

                if (val != PS_SUCCESS) {

                        if (val != PS_NOTSUPPORTED) {

                                pop3_session->state = POP3_ERROR;

                                return -1;

                        }

                }

                if (*body == '+' || *body == '-')

                        body++;

                while (isalpha(*body))

                        body++;

                while (isspace(*body))

                        body++;

        }

        switch (pop3_session->state) {

        case POP3_READY:

        case POP3_GREETING:

                pop3_greeting_recv(pop3_session, body);

#if USE_SSL

                if (pop3_session->ac_prefs->ssl_pop == SSL_STARTTLS)

                        pop3_stls_send(pop3_session);

                else

#endif

                if (pop3_session->ac_prefs->use_apop_auth)

                        pop3_getauth_apop_send(pop3_session);

                else

                        pop3_getauth_user_send(pop3_session);

                break;

#if USE_SSL

        case POP3_STLS:

                if (pop3_stls_recv(pop3_session) != PS_SUCCESS)

                        return -1;

                if (pop3_session->ac_prefs->use_apop_auth)

                        pop3_getauth_apop_send(pop3_session);

                else

                        pop3_getauth_user_send(pop3_session);

                break;

#endif

        case POP3_GETAUTH_USER:

                pop3_getauth_pass_send(pop3_session);

                break;

        case POP3_GETAUTH_PASS:

        case POP3_GETAUTH_APOP:

                pop3_getrange_stat_send(pop3_session);

                break;

        case POP3_GETRANGE_STAT:

                if (pop3_getrange_stat_recv(pop3_session, body) < 0)

                        return -1;

                if (pop3_session->count > 0)

                        pop3_getrange_uidl_send(pop3_session);

                else

                        pop3_logout_send(pop3_session);

                break;

        case POP3_GETRANGE_LAST:

                if (val == PS_NOTSUPPORTED)

                        pop3_session->error_val = PS_SUCCESS;

                else if (pop3_getrange_last_recv(pop3_session, body) < 0)

                        return -1;

                if (pop3_session->cur_msg > 0)

                        pop3_getsize_list_send(pop3_session);

                else

                        pop3_logout_send(pop3_session);

                break;

        case POP3_GETRANGE_UIDL:

                if (val == PS_NOTSUPPORTED) {

                        pop3_session->error_val = PS_SUCCESS;

                        pop3_getrange_last_send(pop3_session);

                } else {

                        pop3_session->state = POP3_GETRANGE_UIDL_RECV;

                        session_recv_data(session, 0, ".\r\n");

                }

                break;

        case POP3_GETSIZE_LIST:

                pop3_session->state = POP3_GETSIZE_LIST_RECV;

                session_recv_data(session, 0, ".\r\n");

                break;

        case POP3_RETR:

                pop3_session->state = POP3_RETR_RECV;

                session_recv_data(session, 0, ".\r\n");

                break;

        case POP3_DELETE:

                pop3_delete_recv(pop3_session);

                if (pop3_session->cur_msg == pop3_session->count)

                        pop3_logout_send(pop3_session);

                else {

                        pop3_session->cur_msg++;

                        if (pop3_lookup_next(pop3_session) == POP3_ERROR)

                                return -1;

                }

                break;

        case POP3_LOGOUT:

                session_disconnect(session);

                break;

        case POP3_ERROR:

        default:

                return -1;

        }

        return 0;

}

static gint pop3_session_recv_data_finished(Session *session, guchar *data,

                                            guint len)

{

        Pop3Session *pop3_session = POP3_SESSION(session);

        Pop3ErrorValue val = PS_SUCCESS;

        switch (pop3_session->state) {

        case POP3_GETRANGE_UIDL_RECV:

                val = pop3_getrange_uidl_recv(pop3_session, data, len);

                if (val == PS_SUCCESS) {

                        if (pop3_session->new_msg_exist)

                                pop3_getsize_list_send(pop3_session);

                        else

                                pop3_logout_send(pop3_session);

                } else

                        return -1;

                break;

        case POP3_GETSIZE_LIST_RECV:

                val = pop3_getsize_list_recv(pop3_session, data, len);

                if (val == PS_SUCCESS) {

                        if (pop3_lookup_next(pop3_session) == POP3_ERROR)

                                return -1;

                } else

                        return -1;

                break;

        case POP3_RETR_RECV:

                if (pop3_retr_recv(pop3_session, data, len) < 0)

                        return -1;

                if (pop3_session->msg[pop3_session->cur_msg].recv_time

                    == RECV_TIME_DELETE ||

                    (pop3_session->ac_prefs->rmmail &&

                     pop3_session->ac_prefs->msg_leave_time == 0 &&

                     pop3_session->msg[pop3_session->cur_msg].recv_time

                     != RECV_TIME_KEEP))

                        pop3_delete_send(pop3_session);

                else if (pop3_session->cur_msg == pop3_session->count)

                        pop3_logout_send(pop3_session);

                else {

                        pop3_session->cur_msg++;

                        if (pop3_lookup_next(pop3_session) == POP3_ERROR)

                                return -1;

                }

                break;

        case POP3_ERROR:

        default:

                return -1;

        }

        return 0;

}