src/lib-master/master-service.c

	master-service.c revision 7fe37c2b0e4cd2a39896ab16e47eb418a59e3934
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen/* Copyright (c) 2005-2010 Dovecot authors, see the included COPYING file */
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen#include "lib.h"
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen#include "lib-signals.h"
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen#include "ioloop.h"
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen#include "array.h"
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen#include "env-util.h"
63a61b7a739ae0f3f520215137d9c50f94d0f34fTimo Sirainen#include "home-expand.h"
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen#include "process-title.h"
18565c69efcd7db003dbf27cf625ed822e889fb1Timo Sirainen#include "restrict-access.h"
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen#include "fd-close-on-exec.h"
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen#include "settings-parser.h"
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen#include "syslog-util.h"
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen#include "master-login.h"
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen#include "master-service-private.h"
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen#include "master-service-settings.h"
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen
01cbf4ac5d44137ab434791be7f838d98d0fcf3bTimo Sirainen#include <stdlib.h>
01cbf4ac5d44137ab434791be7f838d98d0fcf3bTimo Sirainen#include <unistd.h>
7f773564b94e6054a40d3785cb63c29f1e4d4deeTimo Sirainen#include <sys/stat.h>
8af07808ba203f8709e2ff9eaf2291e1c4a4d53dTimo Sirainen#include <syslog.h>
01cbf4ac5d44137ab434791be7f838d98d0fcf3bTimo Sirainen
63a61b7a739ae0f3f520215137d9c50f94d0f34fTimo Sirainen#define DEFAULT_CONFIG_FILE_PATH SYSCONFDIR"/dovecot.conf"
345212e8f61ebf14ff4f80df26df9e655eb5121eTimo Sirainen
63a61b7a739ae0f3f520215137d9c50f94d0f34fTimo Sirainen/* getenv(MASTER_CONFIG_FILE_ENV) provides path to configuration file/socket */
63a61b7a739ae0f3f520215137d9c50f94d0f34fTimo Sirainen#define MASTER_CONFIG_FILE_ENV "CONFIG_FILE"
63a61b7a739ae0f3f520215137d9c50f94d0f34fTimo Sirainen
63a61b7a739ae0f3f520215137d9c50f94d0f34fTimo Sirainen/* getenv(MASTER_DOVECOT_VERSION_ENV) provides master's version number */
63a61b7a739ae0f3f520215137d9c50f94d0f34fTimo Sirainen#define MASTER_DOVECOT_VERSION_ENV "DOVECOT_VERSION"
63a61b7a739ae0f3f520215137d9c50f94d0f34fTimo Sirainen
63a61b7a739ae0f3f520215137d9c50f94d0f34fTimo Sirainen/* when we're full of connections, how often to check if login state has
63a61b7a739ae0f3f520215137d9c50f94d0f34fTimo Sirainen   changed. we normally notice it immediately because of a signal, so this is
63a61b7a739ae0f3f520215137d9c50f94d0f34fTimo Sirainen   just a fallback against race conditions. */
8af07808ba203f8709e2ff9eaf2291e1c4a4d53dTimo Sirainen#define MASTER_SERVICE_STATE_CHECK_MSECS 1000
8af07808ba203f8709e2ff9eaf2291e1c4a4d53dTimo Sirainen
8af07808ba203f8709e2ff9eaf2291e1c4a4d53dTimo Sirainen/* If die callback hasn't managed to stop the service for this many seconds,
8af07808ba203f8709e2ff9eaf2291e1c4a4d53dTimo Sirainen   force it. */
8af07808ba203f8709e2ff9eaf2291e1c4a4d53dTimo Sirainen#define MASTER_SERVICE_DIE_TIMEOUT_MSECS (30*1000)
01cbf4ac5d44137ab434791be7f838d98d0fcf3bTimo Sirainen
01cbf4ac5d44137ab434791be7f838d98d0fcf3bTimo Sirainenstruct master_service *master_service;
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen
7f773564b94e6054a40d3785cb63c29f1e4d4deeTimo Sirainenstatic void master_service_io_listeners_close(struct master_service *service);
7f773564b94e6054a40d3785cb63c29f1e4d4deeTimo Sirainenstatic void master_service_refresh_login_state(struct master_service *service);
7f773564b94e6054a40d3785cb63c29f1e4d4deeTimo Sirainen
7f773564b94e6054a40d3785cb63c29f1e4d4deeTimo Sirainenconst char *master_service_getopt_string(void)
7f773564b94e6054a40d3785cb63c29f1e4d4deeTimo Sirainen{
7f773564b94e6054a40d3785cb63c29f1e4d4deeTimo Sirainen    return "c:ko:Os:L";
7f773564b94e6054a40d3785cb63c29f1e4d4deeTimo Sirainen}
7f773564b94e6054a40d3785cb63c29f1e4d4deeTimo Sirainen
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainenstatic void sig_die(const siginfo_t *si, void *context)
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen{
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    struct master_service *service = context;
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    /* SIGINT comes either from master process or from keyboard. we don't
01cbf4ac5d44137ab434791be7f838d98d0fcf3bTimo Sirainen       want to log it in either case.*/
01cbf4ac5d44137ab434791be7f838d98d0fcf3bTimo Sirainen    if (si->si_signo != SIGINT) {
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen        i_warning("Killed with signal %d (by pid=%s uid=%s code=%s)",
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen              si->si_signo, dec2str(si->si_pid),
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen              dec2str(si->si_uid),
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen              lib_signal_code_to_str(si->si_signo, si->si_code));
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    } else if ((service->flags & MASTER_SERVICE_FLAG_STANDALONE) == 0) {
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen        /* SIGINT came from master. die only if we're not handling
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen           any clients currently. */
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen        if (service->master_status.available_count !=
01cbf4ac5d44137ab434791be7f838d98d0fcf3bTimo Sirainen            service->total_available_count)
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen            return;
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    }
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    io_loop_stop(service->ioloop);
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen}
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainenstatic void
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainensig_state_changed(const siginfo_t *si ATTR_UNUSED, void *context)
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen{
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    struct master_service *service = context;
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    master_service_refresh_login_state(service);
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen}
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainenstatic void master_service_verify_version(struct master_service *service)
345212e8f61ebf14ff4f80df26df9e655eb5121eTimo Sirainen{
345212e8f61ebf14ff4f80df26df9e655eb5121eTimo Sirainen    if (service->version_string != NULL &&
345212e8f61ebf14ff4f80df26df9e655eb5121eTimo Sirainen        strcmp(service->version_string, PACKAGE_VERSION) != 0) {
345212e8f61ebf14ff4f80df26df9e655eb5121eTimo Sirainen        i_fatal("Dovecot version mismatch: "
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen            "Master is v%s, %s is v"PACKAGE_VERSION" "
345212e8f61ebf14ff4f80df26df9e655eb5121eTimo Sirainen            "(if you don't care, set version_ignore=yes)",
345212e8f61ebf14ff4f80df26df9e655eb5121eTimo Sirainen            service->version_string, service->name);
345212e8f61ebf14ff4f80df26df9e655eb5121eTimo Sirainen    }
345212e8f61ebf14ff4f80df26df9e655eb5121eTimo Sirainen}
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainenstruct master_service *
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainenmaster_service_init(const char *name, enum master_service_flags flags,
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen            int *argc, char **argv[], const char *getopt_str)
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen{
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    struct master_service *service;
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    const char *str;
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    i_assert(name != NULL);
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen#ifdef DEBUG
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    if (getenv("GDB") == NULL &&
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen        (flags & MASTER_SERVICE_FLAG_STANDALONE) == 0) {
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen        int count;
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen        str = getenv("SOCKET_COUNT");
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen        count = str == NULL ? 0 : atoi(str);
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen        fd_debug_verify_leaks(MASTER_LISTEN_FD_FIRST + count, 1024);
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    }
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen#endif
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    if ((flags & MASTER_SERVICE_FLAG_STANDALONE) == 0) {
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen        /* make sure we can dump core, at least until
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen           privileges are dropped. (i'm not really sure why this
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen           is needed, because doing the same just before exec
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen           doesn't help, and exec shouldn't affect this with
b2ecd50bb98c44816cb07c17aa17fae2b425f941Timo Sirainen           non-setuid/gid binaries..) */
db7c9201c88e3d9bee10485194ee5b0c67249916Timo Sirainen        restrict_access_allow_coredumps(TRUE);
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    }
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    /* NOTE: we start rooted, so keep the code minimal until
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen       restrict_access_by_env() is called */
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    lib_init();
b2ecd50bb98c44816cb07c17aa17fae2b425f941Timo Sirainen    /* Set a logging prefix temporarily. This will be ignored once the log
b2ecd50bb98c44816cb07c17aa17fae2b425f941Timo Sirainen       is properly initialized */
db7c9201c88e3d9bee10485194ee5b0c67249916Timo Sirainen    i_set_failure_prefix(t_strdup_printf("%s(init): ", name));
18565c69efcd7db003dbf27cf625ed822e889fb1Timo Sirainen
18565c69efcd7db003dbf27cf625ed822e889fb1Timo Sirainen    /* ignore these signals as early as possible */
18565c69efcd7db003dbf27cf625ed822e889fb1Timo Sirainen        lib_signals_ignore(SIGPIPE, TRUE);
18565c69efcd7db003dbf27cf625ed822e889fb1Timo Sirainen        lib_signals_ignore(SIGALRM, FALSE);
18565c69efcd7db003dbf27cf625ed822e889fb1Timo Sirainen
18565c69efcd7db003dbf27cf625ed822e889fb1Timo Sirainen    if (getenv(MASTER_UID_ENV) == NULL)
18565c69efcd7db003dbf27cf625ed822e889fb1Timo Sirainen        flags |= MASTER_SERVICE_FLAG_STANDALONE;
18565c69efcd7db003dbf27cf625ed822e889fb1Timo Sirainen
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    process_title_init(argv);
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    service = i_new(struct master_service, 1);
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    service->argc = *argc;
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    service->argv = *argv;
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    service->name = i_strdup(name);
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    /* keep getopt_str first in case it contains "+" */
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    service->getopt_str = getopt_str == NULL ?
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen        i_strdup(master_service_getopt_string()) :
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen        i_strconcat(getopt_str, master_service_getopt_string(), NULL);
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    service->flags = flags;
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    service->ioloop = io_loop_create();
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    service->service_count_left = (unsigned int)-1;
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    service->config_fd = -1;
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    service->config_path = getenv(MASTER_CONFIG_FILE_ENV);
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    if (service->config_path == NULL) {
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen        service->config_path = DEFAULT_CONFIG_FILE_PATH;
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen        service->config_path_is_default = TRUE;
8fcff4c5b52f24d9c681805fdf06b486f1d0fcbeTimo Sirainen    }

    if ((flags & MASTER_SERVICE_FLAG_STANDALONE) == 0) {
        service->version_string = getenv(MASTER_DOVECOT_VERSION_ENV);
        service->socket_count = 1;
    } else {
        service->version_string = PACKAGE_VERSION;
    }
    str = getenv("SOCKET_COUNT");
    if (str != NULL)
        service->socket_count = atoi(str);
    str = getenv("SSL_SOCKET_COUNT");
    if (str != NULL)
        service->ssl_socket_count = atoi(str);

    /* set up some kind of logging until we know exactly how and where
       we want to log */
    if (getenv("LOG_SERVICE") != NULL)
        i_set_failure_internal();
    if (getenv("USER") != NULL) {
        i_set_failure_prefix(t_strdup_printf("%s(%s): ",
                             name, getenv("USER")));
    } else {
        i_set_failure_prefix(t_strdup_printf("%s: ", name));
    }

    master_service_verify_version(service);
    return service;
}

int master_getopt(struct master_service *service)
{
    int c;

    while ((c = getopt(service->argc, service->argv,
               service->getopt_str)) > 0) {
        if (!master_service_parse_option(service, c, optarg))
            break;
    }
    return c;
}

void master_service_init_log(struct master_service *service,
                 const char *prefix)
{
    const char *path;

    if ((service->flags & MASTER_SERVICE_FLAG_STANDALONE) != 0 &&
        (service->flags & MASTER_SERVICE_FLAG_DONT_LOG_TO_STDERR) == 0) {
        i_set_failure_file("/dev/stderr", "");
        return;
    }

    if (getenv("LOG_SERVICE") != NULL && !service->log_directly) {
        /* logging via log service */
        i_set_failure_internal();
        i_set_failure_prefix(prefix);
        return;
    }

    if (service->set == NULL) {
        i_set_failure_file("/dev/stderr", prefix);
        return;
    }

    if (*service->set->log_path == '\0') {
        /* log to syslog */
        int facility;

        if (!syslog_facility_find(service->set->syslog_facility,
                      &facility))
            facility = LOG_MAIL;
        i_set_failure_syslog("dovecot", LOG_NDELAY, facility);
        i_set_failure_prefix(prefix);
    } else {
        /* log to file or stderr */
        path = home_expand(service->set->log_path);
        i_set_failure_file(path, prefix);
    }

    path = home_expand(service->set->info_log_path);
    if (*path != '\0')
        i_set_info_file(path);

    path = home_expand(service->set->debug_log_path);
    if (*path != '\0')
        i_set_debug_file(path);
    i_set_failure_timestamp_format(service->set->log_timestamp);
}

void master_service_set_die_with_master(struct master_service *service,
                    bool set)
{
    service->die_with_master = set;
}

void master_service_set_die_callback(struct master_service *service,
                     void (*callback)(void))
{
    service->die_callback = callback;
}

bool master_service_parse_option(struct master_service *service,
                 int opt, const char *arg)
{
    switch (opt) {
    case 'c':
        service->config_path = arg;
        service->config_path_is_default = FALSE;
        break;
    case 'k':
        service->keep_environment = TRUE;
        break;
    case 'o':
        if (!array_is_created(&service->config_overrides))
            i_array_init(&service->config_overrides, 16);
        array_append(&service->config_overrides, &arg, 1);
        break;
    case 'O':
        service->flags |= MASTER_SERVICE_FLAG_NO_CONFIG_SETTINGS;
        break;
    case 's':
        if (str_to_uint(arg, &service->socket_count) < 0)
            i_fatal("Invalid socket count: %s", arg);
        break;
    case 'L':
        service->log_directly = TRUE;
        break;
    default:
        return FALSE;
    }
    return TRUE;
}

static void master_service_error(struct master_service *service)
{
    master_service_stop_new_connections(service);
    if (service->master_status.available_count ==
        service->total_available_count || service->die_with_master) {
        if (service->die_callback == NULL)
            master_service_stop(service);
        else {
            service->to_die =
                timeout_add(MASTER_SERVICE_DIE_TIMEOUT_MSECS,
                        master_service_stop,
                        service);
            service->die_callback();
        }
    }
}

static void master_status_error(void *context)
{
    struct master_service *service = context;

    /* status fd is a write-only pipe, so if we're here it means the
       master wants us to die (or died itself). don't die until all
       service connections are finished. */
    io_remove(&service->io_status_error);

    /* the log fd may also be closed already, don't die when trying to
       log later */
    i_set_failure_ignore_errors(TRUE);

    master_service_error(service);
}

void master_service_init_finish(struct master_service *service)
{
    struct stat st;
    const char *value;
    unsigned int count;

    i_assert(service->total_available_count == 0);
    i_assert(service->service_count_left == (unsigned int)-1);

    /* set default signal handlers */
    lib_signals_init();
        lib_signals_set_handler(SIGINT, TRUE, sig_die, service);
    lib_signals_set_handler(SIGTERM, TRUE, sig_die, service);
    if ((service->flags & MASTER_SERVICE_FLAG_TRACK_LOGIN_STATE) != 0) {
        lib_signals_set_handler(SIGUSR1, TRUE,
                    sig_state_changed, service);
    }

    if ((service->flags & MASTER_SERVICE_FLAG_STANDALONE) == 0) {
        if (fstat(MASTER_STATUS_FD, &st) < 0 || !S_ISFIFO(st.st_mode))
            i_fatal("Must be started by dovecot master process");

        /* initialize master_status structure */
        value = getenv(MASTER_UID_ENV);
        if (value == NULL ||
            str_to_uint(value, &service->master_status.uid) < 0)
            i_fatal(MASTER_UID_ENV" missing");
        service->master_status.pid = getpid();

        /* set the default limit */
        value = getenv(MASTER_CLIENT_LIMIT_ENV);
        if (value == NULL || str_to_uint(value, &count) < 0 ||
            count == 0)
            i_fatal(MASTER_CLIENT_LIMIT_ENV" missing");
        master_service_set_client_limit(service, count);

        /* set the default service count */
        value = getenv(MASTER_SERVICE_COUNT_ENV);
        if (value != NULL && str_to_uint(value, &count) == 0 &&
            count > 0)
            master_service_set_service_count(service, count);

        /* start listening errors for status fd, it means master died */
        service->io_status_error = io_add(MASTER_STATUS_FD, IO_ERROR,
                          master_status_error, service);
    } else {
        master_service_set_client_limit(service, 1);
        master_service_set_service_count(service, 1);
    }

    master_service_io_listeners_add(service);

    if ((service->flags & MASTER_SERVICE_FLAG_STD_CLIENT) != 0) {
        /* we already have a connection to be served */
        service->master_status.available_count--;
    }
    master_status_update(service);
}

void master_service_env_clean(bool preserve_home)
{
    const char *user, *tz, *home;
#ifdef DEBUG
    bool gdb = getenv("GDB") != NULL;
#endif

    user = getenv("USER");
    if (user != NULL)
        user = t_strconcat("USER=", user, NULL);
    tz = getenv("TZ");
    if (tz != NULL)
        tz = t_strconcat("TZ=", tz, NULL);
    home = preserve_home ? getenv("HOME") : NULL;
    if (home != NULL)
        home = t_strconcat("HOME=", home, NULL);

    /* Note that if the original environment was set with env_put(), the
       environment strings will be invalid after env_clean(). That's why
       we t_strconcat() them above. */
    env_clean();

    if (user != NULL) env_put(user);
    if (tz != NULL) env_put(tz);
    if (home != NULL) env_put(home);
#ifdef DEBUG
    if (gdb) env_put("GDB=1");
#endif
}

void master_service_set_client_limit(struct master_service *service,
                     unsigned int client_limit)
{
    unsigned int used;

    i_assert(service->master_status.available_count ==
         service->total_available_count);

    used = service->total_available_count -
        service->master_status.available_count;
    i_assert(client_limit >= used);

    service->total_available_count = client_limit;
    service->master_status.available_count = client_limit - used;
}

unsigned int master_service_get_client_limit(struct master_service *service)
{
    return service->total_available_count;
}

void master_service_set_service_count(struct master_service *service,
                      unsigned int count)
{
    unsigned int used;

    used = service->total_available_count -
        service->master_status.available_count;
    i_assert(count >= used);

    if (service->total_available_count > count) {
        service->total_available_count = count;
        service->master_status.available_count = count - used;
    }
    service->service_count_left = count;
}

unsigned int master_service_get_service_count(struct master_service *service)
{
    return service->service_count_left;
}

unsigned int master_service_get_socket_count(struct master_service *service)
{
    return service->socket_count;
}

void master_service_set_avail_overflow_callback(struct master_service *service,
                        void (*callback)(void))
{
    service->avail_overflow_callback = callback;
}

const char *master_service_get_config_path(struct master_service *service)
{
    return service->config_path;
}

const char *master_service_get_version_string(struct master_service *service)
{
    return service->version_string;
}

const char *master_service_get_name(struct master_service *service)
{
    return service->name;
}

void master_service_run(struct master_service *service,
            master_service_connection_callback_t *callback)
{
    service->callback = callback;
    io_loop_run(service->ioloop);
    service->callback = NULL;
}

void master_service_stop(struct master_service *service)
{
        io_loop_stop(service->ioloop);
}

void master_service_stop_new_connections(struct master_service *service)
{
    unsigned int current_count;

    if (service->stopping)
        return;

    service->stopping = TRUE;
    master_service_io_listeners_remove(service);
    master_service_io_listeners_close(service);

    /* make sure we stop after servicing current connections */
    current_count = service->total_available_count -
        service->master_status.available_count;
    service->service_count_left = current_count;
    service->total_available_count = current_count;

    if (current_count == 0)
        master_service_stop(service);
    else {
        /* notify master that we're not accepting any more
           connections */
        service->master_status.available_count = 0;
        master_status_update(service);
    }
    if (service->login != NULL)
        master_login_stop(service->login);
}

void master_service_anvil_send(struct master_service *service, const char *cmd)
{
    ssize_t ret;

    if ((service->flags & MASTER_SERVICE_FLAG_STANDALONE) != 0)
        return;

    ret = write(MASTER_ANVIL_FD, cmd, strlen(cmd));
    if (ret < 0) {
        if (errno == EPIPE) {
            /* anvil process was probably recreated, don't bother
               logging an error about losing connection to it */
            return;
        }
        i_error("write(anvil) failed: %m");
    } else if (ret == 0)
        i_error("write(anvil) failed: EOF");
    else {
        i_assert((size_t)ret == strlen(cmd));
    }
}

void master_service_client_connection_destroyed(struct master_service *service)
{
    /* we can listen again */
    master_service_io_listeners_add(service);

    i_assert(service->total_available_count > 0);
    i_assert(service->service_count_left > 0);

    if (service->service_count_left == service->total_available_count) {
        service->total_available_count--;
                service->service_count_left--;
    } else {
        if (service->service_count_left != (unsigned int)-1)
            service->service_count_left--;

        i_assert(service->master_status.available_count <
             service->total_available_count);
        service->master_status.available_count++;
    }

    if (service->service_count_left == 0) {
        i_assert(service->master_status.available_count ==
             service->total_available_count);
        master_service_stop(service);
    } else if ((service->io_status_error == NULL ||
            service->listeners == NULL) &&
           service->master_status.available_count ==
           service->total_available_count) {
        /* we've finished handling all clients, and
           a) master has closed the connection
           b) there are no listeners (std-client?) */
        master_service_stop(service);
    } else {
        master_status_update(service);
    }
}

static void master_service_set_login_state(struct master_service *service,
                       enum master_login_state state)
{
    if (service->to_overflow_state != NULL)
        timeout_remove(&service->to_overflow_state);

    switch (state) {
    case MASTER_LOGIN_STATE_NONFULL:
        service->call_avail_overflow = FALSE;
        if (service->master_status.available_count > 0)
            return;

        /* some processes should now be able to handle new connections,
           although we can't. but there may be race conditions, so
           make sure that we'll check again soon if the state has
           changed to "full" without our knowledge. */
        service->to_overflow_state =
            timeout_add(MASTER_SERVICE_STATE_CHECK_MSECS,
                    master_service_refresh_login_state,
                    service);
        return;
    case MASTER_LOGIN_STATE_FULL:
        /* make sure we're listening for more connections */
        service->call_avail_overflow = TRUE;
        master_service_io_listeners_add(service);
        return;
    }
    i_error("Invalid master login state: %d", state);
}

static void master_service_refresh_login_state(struct master_service *service)
{
    int ret;

    ret = lseek(MASTER_LOGIN_NOTIFY_FD, 0, SEEK_CUR);
    if (ret < 0)
        i_error("lseek(login notify fd) failed: %m");
    else
        master_service_set_login_state(service, ret);
}

void master_service_close_config_fd(struct master_service *service)
{
    if (service->config_fd != -1) {
        if (close(service->config_fd) < 0)
            i_error("close(master config fd) failed: %m");
        service->config_fd = -1;
    }
}

void master_service_deinit(struct master_service **_service)
{
    struct master_service *service = *_service;

    *_service = NULL;

    master_service_io_listeners_remove(service);

    master_service_close_config_fd(service);
    if (service->to_die != NULL)
        timeout_remove(&service->to_die);
    if (service->to_overflow_state != NULL)
        timeout_remove(&service->to_overflow_state);
    if (service->to_status != NULL)
        timeout_remove(&service->to_status);
    if (service->io_status_error != NULL)
        io_remove(&service->io_status_error);
    if (service->io_status_write != NULL)
        io_remove(&service->io_status_write);
    if (array_is_created(&service->config_overrides))
        array_free(&service->config_overrides);

    if (service->set_parser != NULL) {
        settings_parser_deinit(&service->set_parser);
        pool_unref(&service->set_pool);
    }
    lib_signals_deinit();
    io_loop_destroy(&service->ioloop);

    i_free(service->listeners);
    i_free(service->getopt_str);
    i_free(service->name);
    i_free(service);

    lib_deinit();
}

static void master_service_listen(struct master_service_listener *l)
{
    struct master_service *service = l->service;
    struct master_service_connection conn;

    if (service->master_status.available_count == 0) {
        /* we are full. stop listening for now, unless overflow
           callback destroys one of the existing connections */
        if (service->call_avail_overflow &&
            service->avail_overflow_callback != NULL) {
            service->delay_status_updates = TRUE;
            service->avail_overflow_callback();
            service->delay_status_updates = FALSE;
        }

        if (service->master_status.available_count == 0) {
            master_service_io_listeners_remove(service);
            return;
        }
    }

    memset(&conn, 0, sizeof(conn));
    conn.listen_fd = l->fd;
    conn.fd = net_accept(l->fd, &conn.remote_ip, &conn.remote_port);
    if (conn.fd < 0) {
        if (conn.fd == -1)
            return;

        if (errno != ENOTSOCK) {
            i_error("net_accept() failed: %m");
            master_service_error(service);
            return;
        }
        /* it's not a socket. probably a fifo. use the "listener"
           as the connection fd and stop the listener. */
        conn.fd = l->fd;
        conn.listen_fd = l->fd;
        conn.fifo = TRUE;

        io_remove(&l->io);
        l->fd = -1;
    }
    conn.ssl = l->ssl;
    net_set_nonblock(conn.fd, TRUE);

    i_assert(service->master_status.available_count > 0);
    service->master_status.available_count--;
    master_status_update(service);

    service->callback(&conn);
}

static void io_listeners_init(struct master_service *service)
{
    unsigned int i;

    if (service->socket_count == 0)
        return;

    service->listeners =
        i_new(struct master_service_listener, service->socket_count);

    for (i = 0; i < service->socket_count; i++) {
        struct master_service_listener *l = &service->listeners[i];

        l->service = service;
        l->fd = MASTER_LISTEN_FD_FIRST + i;

        if (i >= service->socket_count - service->ssl_socket_count)
            l->ssl = TRUE;
    }
}

void master_service_io_listeners_add(struct master_service *service)
{
    unsigned int i;

    if (service->stopping)
        return;

    if (service->listeners == NULL)
        io_listeners_init(service);

    for (i = 0; i < service->socket_count; i++) {
        struct master_service_listener *l = &service->listeners[i];

        if (l->io == NULL && l->fd != -1) {
            l->io = io_add(MASTER_LISTEN_FD_FIRST + i, IO_READ,
                       master_service_listen, l);
        }
    }
}

void master_service_io_listeners_remove(struct master_service *service)
{
    unsigned int i;

    if (service->listeners != NULL) {
        for (i = 0; i < service->socket_count; i++) {
            if (service->listeners[i].io != NULL)
                io_remove(&service->listeners[i].io);
        }
    }
}

static void master_service_io_listeners_close(struct master_service *service)
{
    unsigned int i;

    if (service->listeners != NULL) {
        /* close via listeners. some fds might be pipes that are
           currently handled as clients. we don't want to close them. */
        for (i = 0; i < service->socket_count; i++) {
            if (service->listeners[i].fd != -1) {
                if (close(service->listeners[i].fd) < 0) {
                    i_error("close(listener %d) failed: %m",
                        service->listeners[i].fd);
                }
            }
        }
    } else {
        for (i = 0; i < service->socket_count; i++) {
            int fd = MASTER_LISTEN_FD_FIRST + i;

            if (close(fd) < 0)
                i_error("close(listener %d) failed: %m", fd);
        }
    }
}

static bool master_status_update_is_important(struct master_service *service)
{
    if (service->master_status.available_count == 0)
        return TRUE;
    if (!service->initial_status_sent)
        return TRUE;
    return FALSE;
}

void master_status_update(struct master_service *service)
{
    ssize_t ret;
    bool important_update;

    important_update = master_status_update_is_important(service);
    if (service->master_status.pid == 0 || service->delay_status_updates ||
        service->master_status.available_count ==
        service->last_sent_status_avail_count) {
        /* a) closed, b) updating to same state */
        if (service->to_status != NULL)
            timeout_remove(&service->to_status);
        return;
    }
    if (ioloop_time == service->last_sent_status_time &&
        !important_update) {
        /* don't spam master */
        if (service->to_status != NULL)
            timeout_reset(service->to_status);
        else {
            service->to_status =
                timeout_add(1000, master_status_update,
                        service);
        }
        return;
    }

    if (service->to_status != NULL)
        timeout_remove(&service->to_status);

    ret = write(MASTER_STATUS_FD, &service->master_status,
            sizeof(service->master_status));
    if (ret > 0) {
        /* success */
        if (service->io_status_write != NULL) {
            /* delayed important update sent successfully */
            io_remove(&service->io_status_write);
        }
        service->last_sent_status_time = ioloop_time;
        service->last_sent_status_avail_count =
            service->master_status.available_count;
        service->initial_status_sent = TRUE;
    } else if (ret == 0) {
        /* shouldn't happen? */
        i_error("write(master_status_fd) returned 0");
        service->master_status.pid = 0;
    } else if (errno != EAGAIN) {
        /* failure */
        if (errno != EPIPE)
            i_error("write(master_status_fd) failed: %m");
        service->master_status.pid = 0;
    } else if (important_update) {
        /* reader is busy, but it's important to get this notification
           through. send it when possible. */
        if (service->io_status_write == NULL) {
            service->io_status_write =
                io_add(MASTER_STATUS_FD, IO_WRITE,
                       master_status_update, service);
        }
    }
}