src/lmtp/commands.c

	commands.c revision 78a5b3e697af5db96fe0dffed600b0d6370bb8e5
b9f30617c2c96d54acbc4f85ed17b939c4f28916Timo Sirainen/* Copyright (c) 2009-2010 Dovecot authors, see the included COPYING file */
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen
1358e2c58ce29231485a5cfa454756d429ad3d2cTimo Sirainen#include "lib.h"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#include "ioloop.h"
d176f84ce5ca2073f4dfbafb457b9c74f6bf0d76Timo Sirainen#include "array.h"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#include "str.h"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#include "strescape.h"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#include "hostpid.h"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#include "istream.h"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#include "istream-concat.h"
d63b4241643b6014d49ff356f14e0f3ee43068a8Timo Sirainen#include "ostream.h"
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen#include "istream-dot.h"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#include "safe-mkstemp.h"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#include "master-service.h"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#include "rfc822-parser.h"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#include "message-date.h"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#include "auth-master.h"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#include "mail-storage-service.h"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#include "index/raw/raw-storage.h"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#include "lda-settings.h"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#include "lmtp-settings.h"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#include "mail-namespace.h"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#include "mail-deliver.h"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#include "main.h"
02a0492affdff138f43903c19ca366363923044dTimo Sirainen#include "client.h"
02a0492affdff138f43903c19ca366363923044dTimo Sirainen#include "commands.h"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#include "lmtp-proxy.h"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#include <stdlib.h>
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#define ERRSTR_TEMP_MAILBOX_FAIL "451 4.3.0 <%s> Temporary internal error"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#define ERRSTR_TEMP_USERDB_FAIL_PREFIX "451 4.3.0 <%s> "
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#define ERRSTR_TEMP_USERDB_FAIL \
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    ERRSTR_TEMP_USERDB_FAIL_PREFIX "Temporary user lookup failure"
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen#define LMTP_PROXY_DEFAULT_TIMEOUT_MSECS (1000*30)
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainenint cmd_lhlo(struct client *client, const char *args)
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen{
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    struct rfc822_parser_context parser;
6c2ce1d5bf17b21e804a079eb0f973b7ab83e0d8Timo Sirainen    string_t *domain = t_str_new(128);
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    const char *p;
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    int ret = 0;
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    if (*args == '\0') {
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen        client_send_line(client, "501 Missing hostname");
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen        return 0;
97db4761382024093f441e4bc78ba8b6a056504dTimo Sirainen    }
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    /* domain / address-literal */
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    rfc822_parser_init(&parser, (const unsigned char *)args, strlen(args),
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen               NULL);
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    if (*args != '[')
02a0492affdff138f43903c19ca366363923044dTimo Sirainen        ret = rfc822_parse_dot_atom(&parser, domain);
02a0492affdff138f43903c19ca366363923044dTimo Sirainen    else {
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen        for (p = args+1; *p != ']'; p++) {
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen            if (*p == '\\' || *p == '[')
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen                break;
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen        }
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen        if (strcmp(p, "]") != 0)
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen            ret = -1;
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    }
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    if (ret < 0) {
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen        str_truncate(domain, 0);
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen        str_append(domain, "invalid");
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    }
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    client_state_reset(client);
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    client_send_line(client, "250-%s", client->my_domain);
6c2ce1d5bf17b21e804a079eb0f973b7ab83e0d8Timo Sirainen    client_send_line(client, "250-8BITMIME");
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    client_send_line(client, "250-ENHANCEDSTATUSCODES");
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    client_send_line(client, "250 PIPELINING");
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    client->state.lhlo = p_strdup(client->state_pool, str_c(domain));
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    return 0;
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen}
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainenint cmd_mail(struct client *client, const char *args)
383d0e8c24451468d6bea17e4b55d74de744abe6Timo Sirainen{
383d0e8c24451468d6bea17e4b55d74de744abe6Timo Sirainen    const char *addr, *const *argv;
383d0e8c24451468d6bea17e4b55d74de744abe6Timo Sirainen    unsigned int len;
383d0e8c24451468d6bea17e4b55d74de744abe6Timo Sirainen
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen    if (client->state.mail_from != NULL) {
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen        client_send_line(client, "503 5.5.1 MAIL already given");
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen        return 0;
7ceee001c11865a88a311c50c4430867b2d32ce6Timo Sirainen    }
7ceee001c11865a88a311c50c4430867b2d32ce6Timo Sirainen
7ceee001c11865a88a311c50c4430867b2d32ce6Timo Sirainen    argv = t_strsplit(args, " ");
7ceee001c11865a88a311c50c4430867b2d32ce6Timo Sirainen    addr = argv[0] == NULL ? "" : argv[0];
7ceee001c11865a88a311c50c4430867b2d32ce6Timo Sirainen    len = strlen(addr);
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen    if (strncasecmp(addr, "FROM:<", 6) != 0 || addr[len-1] != '>') {
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen        client_send_line(client, "501 5.5.4 Invalid parameters");
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen        return 0;
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen    }
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    for (argv++; *argv != NULL; argv++) {
ce8a6f53ea3ce91b759a54b771e1779564de19a1Timo Sirainen        if (strcasecmp(*argv, "BODY=7BIT") == 0)
ce8a6f53ea3ce91b759a54b771e1779564de19a1Timo Sirainen            client->mail_body_7bit = TRUE;
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen        else if (strcasecmp(*argv, "BODY=8BITMIME") == 0)
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen            client->mail_body_8bitmime = TRUE;
02a0492affdff138f43903c19ca366363923044dTimo Sirainen        else {
02a0492affdff138f43903c19ca366363923044dTimo Sirainen            client_send_line(client,
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen                "501 5.5.4 Unsupported options");
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen            return 0;
02a0492affdff138f43903c19ca366363923044dTimo Sirainen        }
02a0492affdff138f43903c19ca366363923044dTimo Sirainen    }
1cbc0c6372d24168962698c5f4d3e15df8943ebfTimo Sirainen
1cbc0c6372d24168962698c5f4d3e15df8943ebfTimo Sirainen    client->state.mail_from =
1cbc0c6372d24168962698c5f4d3e15df8943ebfTimo Sirainen        p_strndup(client->state_pool, addr + 6, len - 7);
1cbc0c6372d24168962698c5f4d3e15df8943ebfTimo Sirainen    p_array_init(&client->state.rcpt_to, client->state_pool, 64);
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    client_send_line(client, "250 2.1.0 OK");
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    return 0;
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen}
1cbc0c6372d24168962698c5f4d3e15df8943ebfTimo Sirainen
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainenstatic bool
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainenclient_proxy_rcpt_parse_fields(struct lmtp_proxy_settings *set,
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen                   const char *const *args, const char **address)
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen{
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    const char *p, *key, *value;
1cbc0c6372d24168962698c5f4d3e15df8943ebfTimo Sirainen    bool proxying = FALSE, port_set = FALSE;
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    for (; *args != NULL; args++) {
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen        p = strchr(*args, '=');
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen        if (p == NULL) {
97db4761382024093f441e4bc78ba8b6a056504dTimo Sirainen            key = *args;
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen            value = "";
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen        } else {
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen            key = t_strdup_until(*args, p);
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen            value = p + 1;
97db4761382024093f441e4bc78ba8b6a056504dTimo Sirainen        }
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen        if (strcmp(key, "proxy") == 0)
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen            proxying = TRUE;
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen        else if (strcmp(key, "host") == 0)
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen            set->host = value;
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen        else if (strcmp(key, "port") == 0) {
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen            set->port = atoi(value);
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen            port_set = TRUE;
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen        } else if (strcmp(key, "proxy_timeout") == 0)
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen            set->timeout_msecs = atoi(value)*1000;
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen        else if (strcmp(key, "protocol") == 0) {
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen            if (strcmp(value, "lmtp") == 0)
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen                set->protocol = LMTP_CLIENT_PROTOCOL_LMTP;
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen            else if (strcmp(value, "smtp") == 0) {
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen                set->protocol = LMTP_CLIENT_PROTOCOL_SMTP;
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen                if (!port_set)
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen                    set->port = 25;
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen            } else {
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen                i_error("proxy: Unknown protocol %s", value);
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen                return FALSE;
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen            }
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen        } else if (strcmp(key, "user") == 0) {
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen            /* changing the username */
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen            *address = value;
97db4761382024093f441e4bc78ba8b6a056504dTimo Sirainen        } else {
97db4761382024093f441e4bc78ba8b6a056504dTimo Sirainen            /* just ignore it */
97db4761382024093f441e4bc78ba8b6a056504dTimo Sirainen        }
97db4761382024093f441e4bc78ba8b6a056504dTimo Sirainen    }
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    if (proxying && set->host == NULL) {
1358e2c58ce29231485a5cfa454756d429ad3d2cTimo Sirainen        i_error("proxy: host not given");
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen        return FALSE;
d176f84ce5ca2073f4dfbafb457b9c74f6bf0d76Timo Sirainen    }
97db4761382024093f441e4bc78ba8b6a056504dTimo Sirainen    return proxying;
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen}
1358e2c58ce29231485a5cfa454756d429ad3d2cTimo Sirainen
7ceee001c11865a88a311c50c4430867b2d32ce6Timo Sirainenstatic bool
1358e2c58ce29231485a5cfa454756d429ad3d2cTimo Sirainenclient_proxy_is_ourself(const struct client *client,
1358e2c58ce29231485a5cfa454756d429ad3d2cTimo Sirainen            const struct lmtp_proxy_settings *set)
1358e2c58ce29231485a5cfa454756d429ad3d2cTimo Sirainen{
97db4761382024093f441e4bc78ba8b6a056504dTimo Sirainen    struct ip_addr ip;
97db4761382024093f441e4bc78ba8b6a056504dTimo Sirainen
97db4761382024093f441e4bc78ba8b6a056504dTimo Sirainen    if (set->port != client->local_port)
97db4761382024093f441e4bc78ba8b6a056504dTimo Sirainen        return FALSE;
97db4761382024093f441e4bc78ba8b6a056504dTimo Sirainen
97db4761382024093f441e4bc78ba8b6a056504dTimo Sirainen    if (net_addr2ip(set->host, &ip) < 0)
97db4761382024093f441e4bc78ba8b6a056504dTimo Sirainen        return FALSE;
97db4761382024093f441e4bc78ba8b6a056504dTimo Sirainen    if (!net_ip_compare(&ip, &client->local_ip))
1358e2c58ce29231485a5cfa454756d429ad3d2cTimo Sirainen        return FALSE;
d176f84ce5ca2073f4dfbafb457b9c74f6bf0d76Timo Sirainen    return TRUE;
b215a8a123623782554a83f3025ef4e771bd8f01Timo Sirainen}
d176f84ce5ca2073f4dfbafb457b9c74f6bf0d76Timo Sirainen
97db4761382024093f441e4bc78ba8b6a056504dTimo Sirainenstatic bool client_proxy_rcpt(struct client *client, const char *address,
97db4761382024093f441e4bc78ba8b6a056504dTimo Sirainen                  const char *username)
97db4761382024093f441e4bc78ba8b6a056504dTimo Sirainen{
97db4761382024093f441e4bc78ba8b6a056504dTimo Sirainen    struct auth_master_connection *auth_conn;
a64adf62fa33f2463a86f990217b0c9078531a40Timo Sirainen    struct lmtp_proxy_settings set;
    struct auth_user_info info;
    struct mail_storage_service_input input;
    const char *args, *const *fields, *errstr, *orig_username = username;
    pool_t pool;
    int ret;

    memset(&input, 0, sizeof(input));
    input.module = input.service = "lmtp";
    mail_storage_service_init_settings(storage_service, &input);

    memset(&info, 0, sizeof(info));
    info.service = master_service_get_name(master_service);
    info.local_ip = client->local_ip;
    info.remote_ip = client->remote_ip;
    info.local_port = client->local_port;
    info.remote_port = client->remote_port;

    pool = pool_alloconly_create("auth lookup", 1024);
    auth_conn = mail_storage_service_get_auth_conn(storage_service);
    ret = auth_master_pass_lookup(auth_conn, username, &info,
                      pool, &fields);
    if (ret <= 0) {
        errstr = ret < 0 && fields[0] != NULL ? t_strdup(fields[0]) :
            t_strdup_printf(ERRSTR_TEMP_USERDB_FAIL, address);
        pool_unref(&pool);
        if (ret < 0) {
            client_send_line(client, "%s", errstr);
            return TRUE;
        } else {
            /* user not found from passdb. try userdb also. */
            return FALSE;
        }
    }

    memset(&set, 0, sizeof(set));
    set.port = client->local_port;
    set.protocol = LMTP_CLIENT_PROTOCOL_LMTP;
    set.timeout_msecs = LMTP_PROXY_DEFAULT_TIMEOUT_MSECS;

    if (!client_proxy_rcpt_parse_fields(&set, fields, &username)) {
        /* not proxying this user */
        pool_unref(&pool);
        return FALSE;
    }
    if (strcmp(username, orig_username) == 0 &&
        client_proxy_is_ourself(client, &set)) {
        i_error("Proxying to <%s> loops to itself", username);
        client_send_line(client, "554 5.4.6 <%s> "
                 "Proxying loops to itself", address);
        pool_unref(&pool);
        return FALSE;
    }

    if (client->proxy == NULL) {
        client->proxy = lmtp_proxy_init(client->set->hostname,
                        dns_client_socket_path,
                        client->output);
        if (client->mail_body_8bitmime)
            args = " BODY=8BITMIME";
        else if (client->mail_body_7bit)
            args = " BODY=7BIT";
        else
            args = "";
        lmtp_proxy_mail_from(client->proxy, t_strdup_printf(
            "<%s>%s", client->state.mail_from, args));
    }
    if (lmtp_proxy_add_rcpt(client->proxy, address, &set) < 0)
        client_send_line(client, ERRSTR_TEMP_REMOTE_FAILURE);
    else
        client_send_line(client, "250 2.1.5 OK");
    pool_unref(&pool);
    return TRUE;
}

static const char *lmtp_unescape_address(const char *name)
{
    string_t *str;
    const char *p;

    if (*name != '"')
        return name;

    /* quoted-string local-part. drop the quotes unless there's a
       '@' character inside or there's an error. */
    str = t_str_new(128);
    for (p = name+1; *p != '"'; p++) {
        if (*p == '\0')
            return name;
        if (*p == '\\') {
            if (p[1] == '\0') {
                /* error */
                return name;
            }
            p++;
        }
        if (*p == '@')
            return name;
        str_append_c(str, *p);
    }
    p++;
    if (*p != '@' && *p != '\0')
        return name;

    str_append(str, p);
    return str_c(str);
}

static void rcpt_address_parse(struct client *client, const char *address,
                   const char **username_r, const char **detail_r)
{
    const char *p, *p2;

    *username_r = address;
    *detail_r = "";

    if (*client->set->recipient_delimiter == '\0')
        return;

    p = strstr(address, client->set->recipient_delimiter);
    if (p != NULL) {
        /* user+detail@domain */
        *username_r = t_strdup_until(*username_r, p);
        p2 = strchr(p, '@');
        if (p2 == NULL)
            *detail_r = p+1;
        else {
            *detail_r = t_strdup_until(p+1, p2);
            *username_r = t_strconcat(*username_r, p2, NULL);
        }
    }
}

int cmd_rcpt(struct client *client, const char *args)
{
    struct mail_recipient rcpt;
    struct mail_storage_service_input input;
    const char *address, *username, *detail, *prefix;
    const char *error = NULL, *arg, *const *argv;
    unsigned int len;
    int ret = 0;

    if (client->state.mail_from == NULL) {
        client_send_line(client, "503 5.5.1 MAIL needed first");
        return 0;
    }

    argv = t_strsplit(args, " ");
    arg = argv[0] == NULL ? "" : argv[0];
    len = strlen(arg);
    if (strncasecmp(arg, "TO:<", 4) != 0 || arg[len-1] != '>') {
        client_send_line(client, "501 5.5.4 Invalid parameters");
        return 0;
    }
    argv++;

    memset(&rcpt, 0, sizeof(rcpt));
    address = lmtp_unescape_address(t_strndup(arg + 4, len - 5));

    if (*argv != NULL) {
        client_send_line(client, "501 5.5.4 Unsupported options");
        return 0;
    }
    rcpt_address_parse(client, address, &username, &detail);

    if (client->lmtp_set->lmtp_proxy) {
        if (client_proxy_rcpt(client, address, username))
            return 0;
    }

    memset(&input, 0, sizeof(input));
    input.module = input.service = "lmtp";
    input.username = username;
    input.local_ip = client->local_ip;
    input.remote_ip = client->remote_ip;

    ret = mail_storage_service_lookup(storage_service, &input,
                      &rcpt.service_user, &error);

    if (ret < 0) {
        prefix = t_strdup_printf(ERRSTR_TEMP_USERDB_FAIL_PREFIX,
                     username);
        client_send_line(client, "%s%s", prefix, error);
        return 0;
    }
    if (ret == 0) {
        client_send_line(client,
                 "550 5.1.1 <%s> User doesn't exist: %s",
                 address, username);
        return 0;
    }

    rcpt.address = p_strdup(client->state_pool, address);
    rcpt.detail = p_strdup(client->state_pool, detail);
    array_append(&client->state.rcpt_to, &rcpt, 1);

    client_send_line(client, "250 2.1.5 OK");
    return 0;
}

int cmd_quit(struct client *client, const char *args ATTR_UNUSED)
{
    client_destroy(client, "221 2.0.0", "Client quit");
    return -1;
}

int cmd_vrfy(struct client *client, const char *args ATTR_UNUSED)
{
    client_send_line(client, "252 2.3.3 Try RCPT instead");
    return 0;
}

int cmd_rset(struct client *client, const char *args ATTR_UNUSED)
{
    client_state_reset(client);
    client_send_line(client, "250 2.0.0 OK");
    return 0;
}

int cmd_noop(struct client *client, const char *args ATTR_UNUSED)
{
    client_send_line(client, "250 2.0.0 OK");
    return 0;
}

static int
client_deliver(struct client *client, const struct mail_recipient *rcpt,
           struct mail *src_mail)
{
    struct mail_deliver_context dctx;
    struct mail_storage *storage;
    const struct mail_storage_service_input *input;
    void **sets;
    const char *error, *username;
    enum mail_error mail_error;
    int ret;

    input = mail_storage_service_user_get_input(rcpt->service_user);
    username = t_strdup(input->username);

    i_set_failure_prefix(t_strdup_printf("lmtp(%s, %s): ",
                         my_pid, username));
    if (mail_storage_service_next(storage_service, rcpt->service_user,
                      &client->state.dest_user) < 0) {
        client_send_line(client, ERRSTR_TEMP_MAILBOX_FAIL,
                 rcpt->address);
        return -1;
    }
    sets = mail_storage_service_user_get_set(rcpt->service_user);

    memset(&dctx, 0, sizeof(dctx));
    dctx.pool = pool_alloconly_create("mail delivery", 1024);
    dctx.set = sets[1];
    dctx.session_id = client->state.session_id;
    dctx.src_mail = src_mail;
    dctx.src_envelope_sender = client->state.mail_from;
    dctx.dest_user = client->state.dest_user;
    dctx.dest_addr = rcpt->address;
    dctx.dest_mailbox_name = *rcpt->detail == '\0' ? "INBOX" : rcpt->detail;
    dctx.save_dest_mail = array_count(&client->state.rcpt_to) > 1 &&
        client->state.first_saved_mail == NULL;

    if (mail_deliver(&dctx, &storage) == 0) {
        if (dctx.dest_mail != NULL) {
            i_assert(client->state.first_saved_mail == NULL);
            client->state.first_saved_mail = dctx.dest_mail;
        }
        client_send_line(client, "250 2.0.0 <%s> %s Saved",
                 rcpt->address, client->state.session_id);
        ret = 0;
    } else if (storage == NULL) {
        /* This shouldn't happen */
        i_error("BUG: Saving failed to unknown storage");
        client_send_line(client, ERRSTR_TEMP_MAILBOX_FAIL,
                 rcpt->address);
        ret = -1;
    } else {
        error = mail_storage_get_last_error(storage, &mail_error);
        if (mail_error == MAIL_ERROR_NOSPACE) {
            client_send_line(client, "%s <%s> %s",
                     dctx.set->quota_full_tempfail ?
                     "452 4.2.2" : "552 5.2.2",
                     rcpt->address, error);
        } else {
            client_send_line(client, "451 4.2.0 <%s> %s",
                     rcpt->address, error);
        }
        ret = -1;
    }
    pool_unref(&dctx.pool);
    return ret;
}

static bool client_deliver_next(struct client *client, struct mail *src_mail)
{
    const struct mail_recipient *rcpts;
    unsigned int count;
    int ret;

    rcpts = array_get(&client->state.rcpt_to, &count);
    while (client->state.rcpt_idx < count) {
        ret = client_deliver(client, &rcpts[client->state.rcpt_idx],
                     src_mail);
        i_set_failure_prefix(t_strdup_printf("lmtp(%s): ", my_pid));

        client->state.rcpt_idx++;
        if (ret == 0)
            return TRUE;
        /* failed. try the next one. */
        if (client->state.dest_user != NULL)
            mail_user_unref(&client->state.dest_user);
    }
    return FALSE;
}

static void client_rcpt_fail_all(struct client *client)
{
    const struct mail_recipient *rcpt;

    array_foreach(&client->state.rcpt_to, rcpt) {
        client_send_line(client, ERRSTR_TEMP_MAILBOX_FAIL,
                 rcpt->address);
    }
}

static struct istream *client_get_input(struct client *client)
{
    struct client_state *state = &client->state;
    struct istream *cinput, *inputs[3];

    inputs[0] = i_stream_create_from_data(state->added_headers,
                          strlen(state->added_headers));

    if (state->mail_data_output != NULL) {
        o_stream_unref(&state->mail_data_output);
        inputs[1] = i_stream_create_fd(state->mail_data_fd,
                           MAIL_READ_FULL_BLOCK_SIZE,
                           FALSE);
        i_stream_set_init_buffer_size(inputs[1],
                          MAIL_READ_FULL_BLOCK_SIZE);
    } else {
        inputs[1] = i_stream_create_from_data(state->mail_data->data,
                              state->mail_data->used);
    }
    inputs[2] = NULL;

    cinput = i_stream_create_concat(inputs);
    i_stream_unref(&inputs[0]);
    i_stream_unref(&inputs[1]);
    return cinput;
}

static int client_open_raw_mail(struct client *client, struct istream *input)
{
    static const char *wanted_headers[] = {
        "From", "To", "Message-ID", "Subject", "Return-Path",
        NULL
    };
    struct mailbox *box;
    struct raw_mailbox *raw_box;
    struct mailbox_header_lookup_ctx *headers_ctx;
    enum mail_error error;

    client->state.raw_box = box =
        mailbox_alloc(client->raw_mail_user->namespaces->list,
                  "Dovecot Delivery Mail",
                  MAILBOX_FLAG_NO_INDEX_FILES);
    if (mailbox_open_stream(box, input) < 0 ||
        mailbox_sync(box, 0) < 0) {
        i_error("Can't open delivery mail as raw: %s",
            mail_storage_get_last_error(box->storage, &error));
        mailbox_free(&box);
        client_rcpt_fail_all(client);
        return -1;
    }
    raw_box = (struct raw_mailbox *)box;
    raw_box->envelope_sender = client->state.mail_from;

    client->state.raw_trans = mailbox_transaction_begin(box, 0);

    headers_ctx = mailbox_header_lookup_init(box, wanted_headers);
    client->state.raw_mail = mail_alloc(client->state.raw_trans,
                        0, headers_ctx);
    mailbox_header_lookup_unref(&headers_ctx);
    mail_set_seq(client->state.raw_mail, 1);
    return 0;
}

static void
client_input_data_write_local(struct client *client, struct istream *input)
{
    struct mail *src_mail;
    uid_t old_uid, first_uid;

    if (client_open_raw_mail(client, input) < 0)
        return;

    old_uid = geteuid();
    src_mail = client->state.raw_mail;
    while (client_deliver_next(client, src_mail)) {
        if (client->state.first_saved_mail == NULL ||
            client->state.first_saved_mail == src_mail)
            mail_user_unref(&client->state.dest_user);
        else {
            /* use the first saved message to save it elsewhere too.
               this might allow hard linking the files. */
            client->state.dest_user = NULL;
            src_mail = client->state.first_saved_mail;
            first_uid = geteuid();
            i_assert(first_uid != 0);
        }
    }

    if (client->state.first_saved_mail != NULL) {
        struct mail *mail = client->state.first_saved_mail;
        struct mailbox_transaction_context *trans = mail->transaction;
        struct mailbox *box = trans->box;
        struct mail_user *user = box->storage->user;

        /* just in case these functions are going to write anything,
           change uid back to user's own one */
        if (first_uid != old_uid) {
            if (seteuid(0) < 0)
                i_fatal("seteuid(0) failed: %m");
            if (seteuid(first_uid) < 0)
                i_fatal("seteuid() failed: %m");
        }

        mail_free(&mail);
        mailbox_transaction_rollback(&trans);
        mailbox_free(&box);
        mail_user_unref(&user);
    }

    if (old_uid == 0) {
        /* switch back to running as root, since that's what we're
           practically doing anyway. it's also important in case we
           lose e.g. config connection and need to reconnect to it. */
        if (seteuid(0) < 0)
            i_fatal("seteuid(0) failed: %m");
    }
}

static void client_input_data_finish(struct client *client)
{
    client_io_reset(client);
    client_state_reset(client);
    if (i_stream_have_bytes_left(client->input))
        client_input_handle(client);
}

static void client_proxy_finish(bool timeout, void *context)
{
    struct client *client = context;

    lmtp_proxy_deinit(&client->proxy);
    if (timeout) {
        client_destroy(client,
            t_strdup_printf("421 4.4.2 %s", client->my_domain),
            "Disconnected for inactivity");
    } else {
        client_input_data_finish(client);
    }
}

static const char *client_get_added_headers(struct client *client)
{
    string_t *str = t_str_new(200);
    const char *host, *rcpt_to = NULL;

    if (array_count(&client->state.rcpt_to) == 1) {
        const struct mail_recipient *rcpt =
            array_idx(&client->state.rcpt_to, 0);

        rcpt_to = rcpt->address;
    }

    str_printfa(str, "Return-Path: <%s>\r\n", client->state.mail_from);
    if (rcpt_to != NULL)
        str_printfa(str, "Delivered-To: <%s>\r\n", rcpt_to);

    str_printfa(str, "Received: from %s", client->state.lhlo);
    if ((host = net_ip2addr(&client->remote_ip)) != NULL)
        str_printfa(str, " ([%s])", host);
    str_printfa(str, "\r\n\tby %s ("PACKAGE_NAME") with LMTP id %s",
            client->my_domain, client->state.session_id);

    str_append(str, "\r\n\t");
    if (rcpt_to != NULL)
        str_printfa(str, "for <%s>", rcpt_to);
    str_printfa(str, "; %s\r\n", message_date_create(ioloop_time));
    return str_c(str);
}

static bool client_input_data_write(struct client *client)
{
    struct istream *input;
    bool ret = TRUE;

    i_stream_destroy(&client->dot_input);

    input = client_get_input(client);
    client_input_data_write_local(client, input);
    if (client->proxy != NULL) {
        lmtp_proxy_start(client->proxy, input, NULL,
                 client_proxy_finish, client);
        ret = FALSE;
    }
    i_stream_unref(&input);
    return ret;
}

static int client_input_add_file(struct client *client,
                 const unsigned char *data, size_t size)
{
    struct client_state *state = &client->state;
    string_t *path;
    ssize_t ret;
    int fd;

    if (state->mail_data_output != NULL) {
        /* continue writing to file */
        if (o_stream_send(state->mail_data_output,
                  data, size) != (ssize_t)size)
            return -1;
        return 0;
    }

    /* move everything to a temporary file. FIXME: it really shouldn't
       be in /tmp.. */
    path = t_str_new(256);
    str_append(path, "/tmp/dovecot.lmtp.");
    fd = safe_mkstemp_hostpid(path, 0600, (uid_t)-1, (gid_t)-1);
    if (fd == -1)
        return -1;

    /* we just want the fd, unlink it */
    if (unlink(str_c(path)) < 0) {
        /* shouldn't happen.. */
        i_error("unlink(%s) failed: %m", str_c(path));
        (void)close(fd);
        return -1;
    }

    state->mail_data_fd = fd;
    state->mail_data_output = o_stream_create_fd_file(fd, 0, FALSE);
    o_stream_cork(state->mail_data_output);

    ret = o_stream_send(state->mail_data_output,
                state->mail_data->data, state->mail_data->used);
    if (ret != (ssize_t)state->mail_data->used)
        return -1;
    if (o_stream_send(client->state.mail_data_output,
              data, size) != (ssize_t)size)
        return -1;
    return 0;
}

static int
client_input_add(struct client *client, const unsigned char *data, size_t size)
{
    if (client->state.mail_data->used + size <=
        CLIENT_MAIL_DATA_MAX_INMEMORY_SIZE &&
        client->state.mail_data_output == NULL) {
        buffer_append(client->state.mail_data, data, size);
        return 0;
    } else {
        return client_input_add_file(client, data, size);
    }
}

static void client_input_data_handle(struct client *client)
{
    const unsigned char *data;
    size_t size;
    ssize_t ret;

    while ((ret = i_stream_read(client->dot_input)) > 0 || ret == -2) {
        data = i_stream_get_data(client->dot_input, &size);
        if (client_input_add(client, data, size) < 0) {
            client_destroy(client, "451 4.3.0",
                       "Temporary internal failure");
            return;
        }
        i_stream_skip(client->dot_input, size);
    }
    if (ret == 0)
        return;

    if (client_input_data_write(client))
        client_input_data_finish(client);
}

static void client_input_data(struct client *client)
{
    if (client_input_read(client) < 0)
        return;

    client_input_data_handle(client);
}

int cmd_data(struct client *client, const char *args ATTR_UNUSED)
{
    if (client->state.mail_from == NULL) {
        client_send_line(client, "503 5.5.1 MAIL needed first");
        return 0;
    }
    if (array_count(&client->state.rcpt_to) == 0 && client->proxy == NULL) {
        client_send_line(client, "554 5.5.1 No valid recipients");
        return 0;
    }

    client->state.added_headers =
        p_strdup(client->state_pool, client_get_added_headers(client));

    i_assert(client->state.mail_data == NULL);
    client->state.mail_data = buffer_create_dynamic(default_pool, 1024*64);

    i_assert(client->dot_input == NULL);
    client->dot_input = i_stream_create_dot(client->input, TRUE);
    client_send_line(client, "354 OK");

    io_remove(&client->io);
    if (array_count(&client->state.rcpt_to) == 0) {
        timeout_remove(&client->to_idle);
        lmtp_proxy_start(client->proxy, client->dot_input,
                 client->state.added_headers,
                 client_proxy_finish, client);
        i_stream_unref(&client->dot_input);
    } else {
        client->io = io_add(client->fd_in, IO_READ,
                    client_input_data, client);
        client_input_data_handle(client);
    }
    return -1;
}