view src/core/ngx_cycle.c @ 6133:af7eba90645d

Win32: shared memory base addresses and remapping. Two mechanisms are implemented to make it possible to store pointers in shared memory on Windows, in particular on Windows Vista and later versions with ASLR: - The ngx_shm_remap() function added to allow remapping of a shared memory zone to the address originally used for it in the master process. While important, it doesn't solve the problem by itself as in many cases it's not possible to use the address because of conflicts with other allocations. - We now create mappings at the same address in all processes by starting mappings at predefined addresses normally unused by newborn processes. These two mechanisms combined allow to use shared memory on Windows almost without problems, including reloads. Based on the patch by Sergey Brester: http://mailman.nginx.org/pipermail/nginx-devel/2015-April/006836.html
author Maxim Dounin <mdounin@mdounin.ru>
date Mon, 27 Apr 2015 18:25:42 +0300
parents 859ce1c41f64
children 4f6efabcb09b
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>


static void ngx_destroy_cycle_pools(ngx_conf_t *conf);
static ngx_int_t ngx_init_zone_pool(ngx_cycle_t *cycle,
    ngx_shm_zone_t *shm_zone);
static ngx_int_t ngx_test_lockfile(u_char *file, ngx_log_t *log);
static void ngx_clean_old_cycles(ngx_event_t *ev);


volatile ngx_cycle_t  *ngx_cycle;
ngx_array_t            ngx_old_cycles;

static ngx_pool_t     *ngx_temp_pool;
static ngx_event_t     ngx_cleaner_event;

ngx_uint_t             ngx_test_config;
ngx_uint_t             ngx_quiet_mode;


/* STUB NAME */
static ngx_connection_t  dumb;
/* STUB */


ngx_cycle_t *
ngx_init_cycle(ngx_cycle_t *old_cycle)
{
    void                *rv;
    char               **senv, **env;
    ngx_uint_t           i, n;
    ngx_log_t           *log;
    ngx_time_t          *tp;
    ngx_conf_t           conf;
    ngx_pool_t          *pool;
    ngx_cycle_t         *cycle, **old;
    ngx_shm_zone_t      *shm_zone, *oshm_zone;
    ngx_list_part_t     *part, *opart;
    ngx_open_file_t     *file;
    ngx_listening_t     *ls, *nls;
    ngx_core_conf_t     *ccf, *old_ccf;
    ngx_core_module_t   *module;
    char                 hostname[NGX_MAXHOSTNAMELEN];

    ngx_timezone_update();

    /* force localtime update with a new timezone */

    tp = ngx_timeofday();
    tp->sec = 0;

    ngx_time_update();


    log = old_cycle->log;

    pool = ngx_create_pool(NGX_CYCLE_POOL_SIZE, log);
    if (pool == NULL) {
        return NULL;
    }
    pool->log = log;

    cycle = ngx_pcalloc(pool, sizeof(ngx_cycle_t));
    if (cycle == NULL) {
        ngx_destroy_pool(pool);
        return NULL;
    }

    cycle->pool = pool;
    cycle->log = log;
    cycle->old_cycle = old_cycle;

    cycle->conf_prefix.len = old_cycle->conf_prefix.len;
    cycle->conf_prefix.data = ngx_pstrdup(pool, &old_cycle->conf_prefix);
    if (cycle->conf_prefix.data == NULL) {
        ngx_destroy_pool(pool);
        return NULL;
    }

    cycle->prefix.len = old_cycle->prefix.len;
    cycle->prefix.data = ngx_pstrdup(pool, &old_cycle->prefix);
    if (cycle->prefix.data == NULL) {
        ngx_destroy_pool(pool);
        return NULL;
    }

    cycle->conf_file.len = old_cycle->conf_file.len;
    cycle->conf_file.data = ngx_pnalloc(pool, old_cycle->conf_file.len + 1);
    if (cycle->conf_file.data == NULL) {
        ngx_destroy_pool(pool);
        return NULL;
    }
    ngx_cpystrn(cycle->conf_file.data, old_cycle->conf_file.data,
                old_cycle->conf_file.len + 1);

    cycle->conf_param.len = old_cycle->conf_param.len;
    cycle->conf_param.data = ngx_pstrdup(pool, &old_cycle->conf_param);
    if (cycle->conf_param.data == NULL) {
        ngx_destroy_pool(pool);
        return NULL;
    }


    n = old_cycle->paths.nelts ? old_cycle->paths.nelts : 10;

    cycle->paths.elts = ngx_pcalloc(pool, n * sizeof(ngx_path_t *));
    if (cycle->paths.elts == NULL) {
        ngx_destroy_pool(pool);
        return NULL;
    }

    cycle->paths.nelts = 0;
    cycle->paths.size = sizeof(ngx_path_t *);
    cycle->paths.nalloc = n;
    cycle->paths.pool = pool;


    if (old_cycle->open_files.part.nelts) {
        n = old_cycle->open_files.part.nelts;
        for (part = old_cycle->open_files.part.next; part; part = part->next) {
            n += part->nelts;
        }

    } else {
        n = 20;
    }

    if (ngx_list_init(&cycle->open_files, pool, n, sizeof(ngx_open_file_t))
        != NGX_OK)
    {
        ngx_destroy_pool(pool);
        return NULL;
    }


    if (old_cycle->shared_memory.part.nelts) {
        n = old_cycle->shared_memory.part.nelts;
        for (part = old_cycle->shared_memory.part.next; part; part = part->next)
        {
            n += part->nelts;
        }

    } else {
        n = 1;
    }

    if (ngx_list_init(&cycle->shared_memory, pool, n, sizeof(ngx_shm_zone_t))
        != NGX_OK)
    {
        ngx_destroy_pool(pool);
        return NULL;
    }

    n = old_cycle->listening.nelts ? old_cycle->listening.nelts : 10;

    cycle->listening.elts = ngx_pcalloc(pool, n * sizeof(ngx_listening_t));
    if (cycle->listening.elts == NULL) {
        ngx_destroy_pool(pool);
        return NULL;
    }

    cycle->listening.nelts = 0;
    cycle->listening.size = sizeof(ngx_listening_t);
    cycle->listening.nalloc = n;
    cycle->listening.pool = pool;


    ngx_queue_init(&cycle->reusable_connections_queue);


    cycle->conf_ctx = ngx_pcalloc(pool, ngx_max_module * sizeof(void *));
    if (cycle->conf_ctx == NULL) {
        ngx_destroy_pool(pool);
        return NULL;
    }


    if (gethostname(hostname, NGX_MAXHOSTNAMELEN) == -1) {
        ngx_log_error(NGX_LOG_EMERG, log, ngx_errno, "gethostname() failed");
        ngx_destroy_pool(pool);
        return NULL;
    }

    /* on Linux gethostname() silently truncates name that does not fit */

    hostname[NGX_MAXHOSTNAMELEN - 1] = '\0';
    cycle->hostname.len = ngx_strlen(hostname);

    cycle->hostname.data = ngx_pnalloc(pool, cycle->hostname.len);
    if (cycle->hostname.data == NULL) {
        ngx_destroy_pool(pool);
        return NULL;
    }

    ngx_strlow(cycle->hostname.data, (u_char *) hostname, cycle->hostname.len);


    for (i = 0; ngx_modules[i]; i++) {
        if (ngx_modules[i]->type != NGX_CORE_MODULE) {
            continue;
        }

        module = ngx_modules[i]->ctx;

        if (module->create_conf) {
            rv = module->create_conf(cycle);
            if (rv == NULL) {
                ngx_destroy_pool(pool);
                return NULL;
            }
            cycle->conf_ctx[ngx_modules[i]->index] = rv;
        }
    }


    senv = environ;


    ngx_memzero(&conf, sizeof(ngx_conf_t));
    /* STUB: init array ? */
    conf.args = ngx_array_create(pool, 10, sizeof(ngx_str_t));
    if (conf.args == NULL) {
        ngx_destroy_pool(pool);
        return NULL;
    }

    conf.temp_pool = ngx_create_pool(NGX_CYCLE_POOL_SIZE, log);
    if (conf.temp_pool == NULL) {
        ngx_destroy_pool(pool);
        return NULL;
    }


    conf.ctx = cycle->conf_ctx;
    conf.cycle = cycle;
    conf.pool = pool;
    conf.log = log;
    conf.module_type = NGX_CORE_MODULE;
    conf.cmd_type = NGX_MAIN_CONF;

#if 0
    log->log_level = NGX_LOG_DEBUG_ALL;
#endif

    if (ngx_conf_param(&conf) != NGX_CONF_OK) {
        environ = senv;
        ngx_destroy_cycle_pools(&conf);
        return NULL;
    }

    if (ngx_conf_parse(&conf, &cycle->conf_file) != NGX_CONF_OK) {
        environ = senv;
        ngx_destroy_cycle_pools(&conf);
        return NULL;
    }

    if (ngx_test_config && !ngx_quiet_mode) {
        ngx_log_stderr(0, "the configuration file %s syntax is ok",
                       cycle->conf_file.data);
    }

    for (i = 0; ngx_modules[i]; i++) {
        if (ngx_modules[i]->type != NGX_CORE_MODULE) {
            continue;
        }

        module = ngx_modules[i]->ctx;

        if (module->init_conf) {
            if (module->init_conf(cycle, cycle->conf_ctx[ngx_modules[i]->index])
                == NGX_CONF_ERROR)
            {
                environ = senv;
                ngx_destroy_cycle_pools(&conf);
                return NULL;
            }
        }
    }

    if (ngx_process == NGX_PROCESS_SIGNALLER) {
        return cycle;
    }

    ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);

    if (ngx_test_config) {

        if (ngx_create_pidfile(&ccf->pid, log) != NGX_OK) {
            goto failed;
        }

    } else if (!ngx_is_init_cycle(old_cycle)) {

        /*
         * we do not create the pid file in the first ngx_init_cycle() call
         * because we need to write the demonized process pid
         */

        old_ccf = (ngx_core_conf_t *) ngx_get_conf(old_cycle->conf_ctx,
                                                   ngx_core_module);
        if (ccf->pid.len != old_ccf->pid.len
            || ngx_strcmp(ccf->pid.data, old_ccf->pid.data) != 0)
        {
            /* new pid file name */

            if (ngx_create_pidfile(&ccf->pid, log) != NGX_OK) {
                goto failed;
            }

            ngx_delete_pidfile(old_cycle);
        }
    }


    if (ngx_test_lockfile(cycle->lock_file.data, log) != NGX_OK) {
        goto failed;
    }


    if (ngx_create_paths(cycle, ccf->user) != NGX_OK) {
        goto failed;
    }


    if (ngx_log_open_default(cycle) != NGX_OK) {
        goto failed;
    }

    /* open the new files */

    part = &cycle->open_files.part;
    file = part->elts;

    for (i = 0; /* void */ ; i++) {

        if (i >= part->nelts) {
            if (part->next == NULL) {
                break;
            }
            part = part->next;
            file = part->elts;
            i = 0;
        }

        if (file[i].name.len == 0) {
            continue;
        }

        file[i].fd = ngx_open_file(file[i].name.data,
                                   NGX_FILE_APPEND,
                                   NGX_FILE_CREATE_OR_OPEN,
                                   NGX_FILE_DEFAULT_ACCESS);

        ngx_log_debug3(NGX_LOG_DEBUG_CORE, log, 0,
                       "log: %p %d \"%s\"",
                       &file[i], file[i].fd, file[i].name.data);

        if (file[i].fd == NGX_INVALID_FILE) {
            ngx_log_error(NGX_LOG_EMERG, log, ngx_errno,
                          ngx_open_file_n " \"%s\" failed",
                          file[i].name.data);
            goto failed;
        }

#if !(NGX_WIN32)
        if (fcntl(file[i].fd, F_SETFD, FD_CLOEXEC) == -1) {
            ngx_log_error(NGX_LOG_EMERG, log, ngx_errno,
                          "fcntl(FD_CLOEXEC) \"%s\" failed",
                          file[i].name.data);
            goto failed;
        }
#endif
    }

    cycle->log = &cycle->new_log;
    pool->log = &cycle->new_log;


    /* create shared memory */

    part = &cycle->shared_memory.part;
    shm_zone = part->elts;

    for (i = 0; /* void */ ; i++) {

        if (i >= part->nelts) {
            if (part->next == NULL) {
                break;
            }
            part = part->next;
            shm_zone = part->elts;
            i = 0;
        }

        if (shm_zone[i].shm.size == 0) {
            ngx_log_error(NGX_LOG_EMERG, log, 0,
                          "zero size shared memory zone \"%V\"",
                          &shm_zone[i].shm.name);
            goto failed;
        }

        shm_zone[i].shm.log = cycle->log;

        opart = &old_cycle->shared_memory.part;
        oshm_zone = opart->elts;

        for (n = 0; /* void */ ; n++) {

            if (n >= opart->nelts) {
                if (opart->next == NULL) {
                    break;
                }
                opart = opart->next;
                oshm_zone = opart->elts;
                n = 0;
            }

            if (shm_zone[i].shm.name.len != oshm_zone[n].shm.name.len) {
                continue;
            }

            if (ngx_strncmp(shm_zone[i].shm.name.data,
                            oshm_zone[n].shm.name.data,
                            shm_zone[i].shm.name.len)
                != 0)
            {
                continue;
            }

            if (shm_zone[i].tag == oshm_zone[n].tag
                && shm_zone[i].shm.size == oshm_zone[n].shm.size
                && !shm_zone[i].noreuse)
            {
                shm_zone[i].shm.addr = oshm_zone[n].shm.addr;
#if (NGX_WIN32)
                shm_zone[i].shm.handle = oshm_zone[n].shm.handle;
#endif

                if (shm_zone[i].init(&shm_zone[i], oshm_zone[n].data)
                    != NGX_OK)
                {
                    goto failed;
                }

                goto shm_zone_found;
            }

            ngx_shm_free(&oshm_zone[n].shm);

            break;
        }

        if (ngx_shm_alloc(&shm_zone[i].shm) != NGX_OK) {
            goto failed;
        }

        if (ngx_init_zone_pool(cycle, &shm_zone[i]) != NGX_OK) {
            goto failed;
        }

        if (shm_zone[i].init(&shm_zone[i], NULL) != NGX_OK) {
            goto failed;
        }

    shm_zone_found:

        continue;
    }


    /* handle the listening sockets */

    if (old_cycle->listening.nelts) {
        ls = old_cycle->listening.elts;
        for (i = 0; i < old_cycle->listening.nelts; i++) {
            ls[i].remain = 0;
        }

        nls = cycle->listening.elts;
        for (n = 0; n < cycle->listening.nelts; n++) {

            for (i = 0; i < old_cycle->listening.nelts; i++) {
                if (ls[i].ignore) {
                    continue;
                }

                if (ngx_cmp_sockaddr(nls[n].sockaddr, nls[n].socklen,
                                     ls[i].sockaddr, ls[i].socklen, 1)
                    == NGX_OK)
                {
                    nls[n].fd = ls[i].fd;
                    nls[n].previous = &ls[i];
                    ls[i].remain = 1;

                    if (ls[i].backlog != nls[n].backlog) {
                        nls[n].listen = 1;
                    }

#if (NGX_HAVE_DEFERRED_ACCEPT && defined SO_ACCEPTFILTER)

                    /*
                     * FreeBSD, except the most recent versions,
                     * could not remove accept filter
                     */
                    nls[n].deferred_accept = ls[i].deferred_accept;

                    if (ls[i].accept_filter && nls[n].accept_filter) {
                        if (ngx_strcmp(ls[i].accept_filter,
                                       nls[n].accept_filter)
                            != 0)
                        {
                            nls[n].delete_deferred = 1;
                            nls[n].add_deferred = 1;
                        }

                    } else if (ls[i].accept_filter) {
                        nls[n].delete_deferred = 1;

                    } else if (nls[n].accept_filter) {
                        nls[n].add_deferred = 1;
                    }
#endif

#if (NGX_HAVE_DEFERRED_ACCEPT && defined TCP_DEFER_ACCEPT)

                    if (ls[i].deferred_accept && !nls[n].deferred_accept) {
                        nls[n].delete_deferred = 1;

                    } else if (ls[i].deferred_accept != nls[n].deferred_accept)
                    {
                        nls[n].add_deferred = 1;
                    }
#endif
                    break;
                }
            }

            if (nls[n].fd == (ngx_socket_t) -1) {
                nls[n].open = 1;
#if (NGX_HAVE_DEFERRED_ACCEPT && defined SO_ACCEPTFILTER)
                if (nls[n].accept_filter) {
                    nls[n].add_deferred = 1;
                }
#endif
#if (NGX_HAVE_DEFERRED_ACCEPT && defined TCP_DEFER_ACCEPT)
                if (nls[n].deferred_accept) {
                    nls[n].add_deferred = 1;
                }
#endif
            }
        }

    } else {
        ls = cycle->listening.elts;
        for (i = 0; i < cycle->listening.nelts; i++) {
            ls[i].open = 1;
#if (NGX_HAVE_DEFERRED_ACCEPT && defined SO_ACCEPTFILTER)
            if (ls[i].accept_filter) {
                ls[i].add_deferred = 1;
            }
#endif
#if (NGX_HAVE_DEFERRED_ACCEPT && defined TCP_DEFER_ACCEPT)
            if (ls[i].deferred_accept) {
                ls[i].add_deferred = 1;
            }
#endif
        }
    }

    if (ngx_open_listening_sockets(cycle) != NGX_OK) {
        goto failed;
    }

    if (!ngx_test_config) {
        ngx_configure_listening_sockets(cycle);
    }


    /* commit the new cycle configuration */

    if (!ngx_use_stderr) {
        (void) ngx_log_redirect_stderr(cycle);
    }

    pool->log = cycle->log;

    for (i = 0; ngx_modules[i]; i++) {
        if (ngx_modules[i]->init_module) {
            if (ngx_modules[i]->init_module(cycle) != NGX_OK) {
                /* fatal */
                exit(1);
            }
        }
    }


    /* close and delete stuff that lefts from an old cycle */

    /* free the unnecessary shared memory */

    opart = &old_cycle->shared_memory.part;
    oshm_zone = opart->elts;

    for (i = 0; /* void */ ; i++) {

        if (i >= opart->nelts) {
            if (opart->next == NULL) {
                goto old_shm_zone_done;
            }
            opart = opart->next;
            oshm_zone = opart->elts;
            i = 0;
        }

        part = &cycle->shared_memory.part;
        shm_zone = part->elts;

        for (n = 0; /* void */ ; n++) {

            if (n >= part->nelts) {
                if (part->next == NULL) {
                    break;
                }
                part = part->next;
                shm_zone = part->elts;
                n = 0;
            }

            if (oshm_zone[i].shm.name.len == shm_zone[n].shm.name.len
                && ngx_strncmp(oshm_zone[i].shm.name.data,
                               shm_zone[n].shm.name.data,
                               oshm_zone[i].shm.name.len)
                == 0)
            {
                goto live_shm_zone;
            }
        }

        ngx_shm_free(&oshm_zone[i].shm);

    live_shm_zone:

        continue;
    }

old_shm_zone_done:


    /* close the unnecessary listening sockets */

    ls = old_cycle->listening.elts;
    for (i = 0; i < old_cycle->listening.nelts; i++) {

        if (ls[i].remain || ls[i].fd == (ngx_socket_t) -1) {
            continue;
        }

        if (ngx_close_socket(ls[i].fd) == -1) {
            ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
                          ngx_close_socket_n " listening socket on %V failed",
                          &ls[i].addr_text);
        }

#if (NGX_HAVE_UNIX_DOMAIN)

        if (ls[i].sockaddr->sa_family == AF_UNIX) {
            u_char  *name;

            name = ls[i].addr_text.data + sizeof("unix:") - 1;

            ngx_log_error(NGX_LOG_WARN, cycle->log, 0,
                          "deleting socket %s", name);

            if (ngx_delete_file(name) == NGX_FILE_ERROR) {
                ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_socket_errno,
                              ngx_delete_file_n " %s failed", name);
            }
        }

#endif
    }


    /* close the unnecessary open files */

    part = &old_cycle->open_files.part;
    file = part->elts;

    for (i = 0; /* void */ ; i++) {

        if (i >= part->nelts) {
            if (part->next == NULL) {
                break;
            }
            part = part->next;
            file = part->elts;
            i = 0;
        }

        if (file[i].fd == NGX_INVALID_FILE || file[i].fd == ngx_stderr) {
            continue;
        }

        if (ngx_close_file(file[i].fd) == NGX_FILE_ERROR) {
            ngx_log_error(NGX_LOG_EMERG, log, ngx_errno,
                          ngx_close_file_n " \"%s\" failed",
                          file[i].name.data);
        }
    }

    ngx_destroy_pool(conf.temp_pool);

    if (ngx_process == NGX_PROCESS_MASTER || ngx_is_init_cycle(old_cycle)) {

        /*
         * perl_destruct() frees environ, if it is not the same as it was at
         * perl_construct() time, therefore we save the previous cycle
         * environment before ngx_conf_parse() where it will be changed.
         */

        env = environ;
        environ = senv;

        ngx_destroy_pool(old_cycle->pool);
        cycle->old_cycle = NULL;

        environ = env;

        return cycle;
    }


    if (ngx_temp_pool == NULL) {
        ngx_temp_pool = ngx_create_pool(128, cycle->log);
        if (ngx_temp_pool == NULL) {
            ngx_log_error(NGX_LOG_EMERG, cycle->log, 0,
                          "could not create ngx_temp_pool");
            exit(1);
        }

        n = 10;
        ngx_old_cycles.elts = ngx_pcalloc(ngx_temp_pool,
                                          n * sizeof(ngx_cycle_t *));
        if (ngx_old_cycles.elts == NULL) {
            exit(1);
        }
        ngx_old_cycles.nelts = 0;
        ngx_old_cycles.size = sizeof(ngx_cycle_t *);
        ngx_old_cycles.nalloc = n;
        ngx_old_cycles.pool = ngx_temp_pool;

        ngx_cleaner_event.handler = ngx_clean_old_cycles;
        ngx_cleaner_event.log = cycle->log;
        ngx_cleaner_event.data = &dumb;
        dumb.fd = (ngx_socket_t) -1;
    }

    ngx_temp_pool->log = cycle->log;

    old = ngx_array_push(&ngx_old_cycles);
    if (old == NULL) {
        exit(1);
    }
    *old = old_cycle;

    if (!ngx_cleaner_event.timer_set) {
        ngx_add_timer(&ngx_cleaner_event, 30000);
        ngx_cleaner_event.timer_set = 1;
    }

    return cycle;


failed:

    if (!ngx_is_init_cycle(old_cycle)) {
        old_ccf = (ngx_core_conf_t *) ngx_get_conf(old_cycle->conf_ctx,
                                                   ngx_core_module);
        if (old_ccf->environment) {
            environ = old_ccf->environment;
        }
    }

    /* rollback the new cycle configuration */

    part = &cycle->open_files.part;
    file = part->elts;

    for (i = 0; /* void */ ; i++) {

        if (i >= part->nelts) {
            if (part->next == NULL) {
                break;
            }
            part = part->next;
            file = part->elts;
            i = 0;
        }

        if (file[i].fd == NGX_INVALID_FILE || file[i].fd == ngx_stderr) {
            continue;
        }

        if (ngx_close_file(file[i].fd) == NGX_FILE_ERROR) {
            ngx_log_error(NGX_LOG_EMERG, log, ngx_errno,
                          ngx_close_file_n " \"%s\" failed",
                          file[i].name.data);
        }
    }

    if (ngx_test_config) {
        ngx_destroy_cycle_pools(&conf);
        return NULL;
    }

    ls = cycle->listening.elts;
    for (i = 0; i < cycle->listening.nelts; i++) {
        if (ls[i].fd == (ngx_socket_t) -1 || !ls[i].open) {
            continue;
        }

        if (ngx_close_socket(ls[i].fd) == -1) {
            ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
                          ngx_close_socket_n " %V failed",
                          &ls[i].addr_text);
        }
    }

    ngx_destroy_cycle_pools(&conf);

    return NULL;
}


static void
ngx_destroy_cycle_pools(ngx_conf_t *conf)
{
    ngx_destroy_pool(conf->temp_pool);
    ngx_destroy_pool(conf->pool);
}


static ngx_int_t
ngx_init_zone_pool(ngx_cycle_t *cycle, ngx_shm_zone_t *zn)
{
    u_char           *file;
    ngx_slab_pool_t  *sp;

    sp = (ngx_slab_pool_t *) zn->shm.addr;

    if (zn->shm.exists) {

        if (sp == sp->addr) {
            return NGX_OK;
        }

#if (NGX_WIN32)

        /* remap at the required address */

        if (ngx_shm_remap(&zn->shm, sp->addr) != NGX_OK) {
            return NGX_ERROR;
        }

        sp = (ngx_slab_pool_t *) zn->shm.addr;

        if (sp == sp->addr) {
            return NGX_OK;
        }

#endif

        ngx_log_error(NGX_LOG_EMERG, cycle->log, 0,
                      "shared zone \"%V\" has no equal addresses: %p vs %p",
                      &zn->shm.name, sp->addr, sp);
        return NGX_ERROR;
    }

    sp->end = zn->shm.addr + zn->shm.size;
    sp->min_shift = 3;
    sp->addr = zn->shm.addr;

#if (NGX_HAVE_ATOMIC_OPS)

    file = NULL;

#else

    file = ngx_pnalloc(cycle->pool, cycle->lock_file.len + zn->shm.name.len);
    if (file == NULL) {
        return NGX_ERROR;
    }

    (void) ngx_sprintf(file, "%V%V%Z", &cycle->lock_file, &zn->shm.name);

#endif

    if (ngx_shmtx_create(&sp->mutex, &sp->lock, file) != NGX_OK) {
        return NGX_ERROR;
    }

    ngx_slab_init(sp);

    return NGX_OK;
}


ngx_int_t
ngx_create_pidfile(ngx_str_t *name, ngx_log_t *log)
{
    size_t      len;
    ngx_uint_t  create;
    ngx_file_t  file;
    u_char      pid[NGX_INT64_LEN + 2];

    if (ngx_process > NGX_PROCESS_MASTER) {
        return NGX_OK;
    }

    ngx_memzero(&file, sizeof(ngx_file_t));

    file.name = *name;
    file.log = log;

    create = ngx_test_config ? NGX_FILE_CREATE_OR_OPEN : NGX_FILE_TRUNCATE;

    file.fd = ngx_open_file(file.name.data, NGX_FILE_RDWR,
                            create, NGX_FILE_DEFAULT_ACCESS);

    if (file.fd == NGX_INVALID_FILE) {
        ngx_log_error(NGX_LOG_EMERG, log, ngx_errno,
                      ngx_open_file_n " \"%s\" failed", file.name.data);
        return NGX_ERROR;
    }

    if (!ngx_test_config) {
        len = ngx_snprintf(pid, NGX_INT64_LEN + 2, "%P%N", ngx_pid) - pid;

        if (ngx_write_file(&file, pid, len, 0) == NGX_ERROR) {
            return NGX_ERROR;
        }
    }

    if (ngx_close_file(file.fd) == NGX_FILE_ERROR) {
        ngx_log_error(NGX_LOG_ALERT, log, ngx_errno,
                      ngx_close_file_n " \"%s\" failed", file.name.data);
    }

    return NGX_OK;
}


void
ngx_delete_pidfile(ngx_cycle_t *cycle)
{
    u_char           *name;
    ngx_core_conf_t  *ccf;

    ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);

    name = ngx_new_binary ? ccf->oldpid.data : ccf->pid.data;

    if (ngx_delete_file(name) == NGX_FILE_ERROR) {
        ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
                      ngx_delete_file_n " \"%s\" failed", name);
    }
}


ngx_int_t
ngx_signal_process(ngx_cycle_t *cycle, char *sig)
{
    ssize_t           n;
    ngx_int_t         pid;
    ngx_file_t        file;
    ngx_core_conf_t  *ccf;
    u_char            buf[NGX_INT64_LEN + 2];

    ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0, "signal process started");

    ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);

    ngx_memzero(&file, sizeof(ngx_file_t));

    file.name = ccf->pid;
    file.log = cycle->log;

    file.fd = ngx_open_file(file.name.data, NGX_FILE_RDONLY,
                            NGX_FILE_OPEN, NGX_FILE_DEFAULT_ACCESS);

    if (file.fd == NGX_INVALID_FILE) {
        ngx_log_error(NGX_LOG_ERR, cycle->log, ngx_errno,
                      ngx_open_file_n " \"%s\" failed", file.name.data);
        return 1;
    }

    n = ngx_read_file(&file, buf, NGX_INT64_LEN + 2, 0);

    if (ngx_close_file(file.fd) == NGX_FILE_ERROR) {
        ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
                      ngx_close_file_n " \"%s\" failed", file.name.data);
    }

    if (n == NGX_ERROR) {
        return 1;
    }

    while (n-- && (buf[n] == CR || buf[n] == LF)) { /* void */ }

    pid = ngx_atoi(buf, ++n);

    if (pid == NGX_ERROR) {
        ngx_log_error(NGX_LOG_ERR, cycle->log, 0,
                      "invalid PID number \"%*s\" in \"%s\"",
                      n, buf, file.name.data);
        return 1;
    }

    return ngx_os_signal_process(cycle, sig, pid);

}


static ngx_int_t
ngx_test_lockfile(u_char *file, ngx_log_t *log)
{
#if !(NGX_HAVE_ATOMIC_OPS)
    ngx_fd_t  fd;

    fd = ngx_open_file(file, NGX_FILE_RDWR, NGX_FILE_CREATE_OR_OPEN,
                       NGX_FILE_DEFAULT_ACCESS);

    if (fd == NGX_INVALID_FILE) {
        ngx_log_error(NGX_LOG_EMERG, log, ngx_errno,
                      ngx_open_file_n " \"%s\" failed", file);
        return NGX_ERROR;
    }

    if (ngx_close_file(fd) == NGX_FILE_ERROR) {
        ngx_log_error(NGX_LOG_ALERT, log, ngx_errno,
                      ngx_close_file_n " \"%s\" failed", file);
    }

    if (ngx_delete_file(file) == NGX_FILE_ERROR) {
        ngx_log_error(NGX_LOG_ALERT, log, ngx_errno,
                      ngx_delete_file_n " \"%s\" failed", file);
    }

#endif

    return NGX_OK;
}


void
ngx_reopen_files(ngx_cycle_t *cycle, ngx_uid_t user)
{
    ngx_fd_t          fd;
    ngx_uint_t        i;
    ngx_list_part_t  *part;
    ngx_open_file_t  *file;

    part = &cycle->open_files.part;
    file = part->elts;

    for (i = 0; /* void */ ; i++) {

        if (i >= part->nelts) {
            if (part->next == NULL) {
                break;
            }
            part = part->next;
            file = part->elts;
            i = 0;
        }

        if (file[i].name.len == 0) {
            continue;
        }

        if (file[i].flush) {
            file[i].flush(&file[i], cycle->log);
        }

        fd = ngx_open_file(file[i].name.data, NGX_FILE_APPEND,
                           NGX_FILE_CREATE_OR_OPEN, NGX_FILE_DEFAULT_ACCESS);

        ngx_log_debug3(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
                       "reopen file \"%s\", old:%d new:%d",
                       file[i].name.data, file[i].fd, fd);

        if (fd == NGX_INVALID_FILE) {
            ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
                          ngx_open_file_n " \"%s\" failed", file[i].name.data);
            continue;
        }

#if !(NGX_WIN32)
        if (user != (ngx_uid_t) NGX_CONF_UNSET_UINT) {
            ngx_file_info_t  fi;

            if (ngx_file_info((const char *) file[i].name.data, &fi)
                == NGX_FILE_ERROR)
            {
                ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
                              ngx_file_info_n " \"%s\" failed",
                              file[i].name.data);

                if (ngx_close_file(fd) == NGX_FILE_ERROR) {
                    ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
                                  ngx_close_file_n " \"%s\" failed",
                                  file[i].name.data);
                }

                continue;
            }

            if (fi.st_uid != user) {
                if (chown((const char *) file[i].name.data, user, -1) == -1) {
                    ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
                                  "chown(\"%s\", %d) failed",
                                  file[i].name.data, user);

                    if (ngx_close_file(fd) == NGX_FILE_ERROR) {
                        ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
                                      ngx_close_file_n " \"%s\" failed",
                                      file[i].name.data);
                    }

                    continue;
                }
            }

            if ((fi.st_mode & (S_IRUSR|S_IWUSR)) != (S_IRUSR|S_IWUSR)) {

                fi.st_mode |= (S_IRUSR|S_IWUSR);

                if (chmod((const char *) file[i].name.data, fi.st_mode) == -1) {
                    ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
                                  "chmod() \"%s\" failed", file[i].name.data);

                    if (ngx_close_file(fd) == NGX_FILE_ERROR) {
                        ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
                                      ngx_close_file_n " \"%s\" failed",
                                      file[i].name.data);
                    }

                    continue;
                }
            }
        }

        if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1) {
            ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
                          "fcntl(FD_CLOEXEC) \"%s\" failed",
                          file[i].name.data);

            if (ngx_close_file(fd) == NGX_FILE_ERROR) {
                ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
                              ngx_close_file_n " \"%s\" failed",
                              file[i].name.data);
            }

            continue;
        }
#endif

        if (ngx_close_file(file[i].fd) == NGX_FILE_ERROR) {
            ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
                          ngx_close_file_n " \"%s\" failed",
                          file[i].name.data);
        }

        file[i].fd = fd;
    }

    (void) ngx_log_redirect_stderr(cycle);
}


ngx_shm_zone_t *
ngx_shared_memory_add(ngx_conf_t *cf, ngx_str_t *name, size_t size, void *tag)
{
    ngx_uint_t        i;
    ngx_shm_zone_t   *shm_zone;
    ngx_list_part_t  *part;

    part = &cf->cycle->shared_memory.part;
    shm_zone = part->elts;

    for (i = 0; /* void */ ; i++) {

        if (i >= part->nelts) {
            if (part->next == NULL) {
                break;
            }
            part = part->next;
            shm_zone = part->elts;
            i = 0;
        }

        if (name->len != shm_zone[i].shm.name.len) {
            continue;
        }

        if (ngx_strncmp(name->data, shm_zone[i].shm.name.data, name->len)
            != 0)
        {
            continue;
        }

        if (tag != shm_zone[i].tag) {
            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                            "the shared memory zone \"%V\" is "
                            "already declared for a different use",
                            &shm_zone[i].shm.name);
            return NULL;
        }

        if (shm_zone[i].shm.size == 0) {
            shm_zone[i].shm.size = size;
        }

        if (size && size != shm_zone[i].shm.size) {
            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                            "the size %uz of shared memory zone \"%V\" "
                            "conflicts with already declared size %uz",
                            size, &shm_zone[i].shm.name, shm_zone[i].shm.size);
            return NULL;
        }

        return &shm_zone[i];
    }

    shm_zone = ngx_list_push(&cf->cycle->shared_memory);

    if (shm_zone == NULL) {
        return NULL;
    }

    shm_zone->data = NULL;
    shm_zone->shm.log = cf->cycle->log;
    shm_zone->shm.size = size;
    shm_zone->shm.name = *name;
    shm_zone->shm.exists = 0;
    shm_zone->init = NULL;
    shm_zone->tag = tag;
    shm_zone->noreuse = 0;

    return shm_zone;
}


static void
ngx_clean_old_cycles(ngx_event_t *ev)
{
    ngx_uint_t     i, n, found, live;
    ngx_log_t     *log;
    ngx_cycle_t  **cycle;

    log = ngx_cycle->log;
    ngx_temp_pool->log = log;

    ngx_log_debug0(NGX_LOG_DEBUG_CORE, log, 0, "clean old cycles");

    live = 0;

    cycle = ngx_old_cycles.elts;
    for (i = 0; i < ngx_old_cycles.nelts; i++) {

        if (cycle[i] == NULL) {
            continue;
        }

        found = 0;

        for (n = 0; n < cycle[i]->connection_n; n++) {
            if (cycle[i]->connections[n].fd != (ngx_socket_t) -1) {
                found = 1;

                ngx_log_debug1(NGX_LOG_DEBUG_CORE, log, 0, "live fd:%d", n);

                break;
            }
        }

        if (found) {
            live = 1;
            continue;
        }

        ngx_log_debug1(NGX_LOG_DEBUG_CORE, log, 0, "clean old cycle: %d", i);

        ngx_destroy_pool(cycle[i]->pool);
        cycle[i] = NULL;
    }

    ngx_log_debug1(NGX_LOG_DEBUG_CORE, log, 0, "old cycles status: %d", live);

    if (live) {
        ngx_add_timer(ev, 30000);

    } else {
        ngx_destroy_pool(ngx_temp_pool);
        ngx_temp_pool = NULL;
        ngx_old_cycles.nelts = 0;
    }
}