eventl.c

Go to the documentation of this file.

/* This file is part of Pazpar2.
 Copyright (C) Index Data
 
 Pazpar2 is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free
 Software Foundation; either version 2, or (at your option) any later
 version.
 
 Pazpar2 is distributed in the hope that it will be useful, but WITHOUT ANY
 WARRANTY; without even the implied warranty of MERCHANTABILITY or
 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 for more details.
 
 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
 */
 
/*
 * Based on  ParaZ - a simple tool for harvesting performance data for
 * parallel operations using Z39.50.
 * Copyright (C) Index Data ApS
 * See LICENSE file for details.
 */
 
/*
 * Based on revision YAZ' server/eventl.c 1.29.
 */
 
#if HAVE_CONFIG_H
#include <config.h>
#endif
 
#include <math.h>
#include <stdio.h>
#include <assert.h>
 
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
 
#include <stdlib.h>
#include <errno.h>
#include <string.h>
 
#include <yaz/yconfig.h>
#include <yaz/log.h>
#include <yaz/comstack.h>
#include <yaz/xmalloc.h>
#include <yaz/mutex.h>
#include <yaz/poll.h>
#if HAVE_GETRLIMIT
#include <sys/resource.h>
#endif
#include "eventl.h"
#include "sel_thread.h"
 
#if 1
static YAZ_MUTEX g_mutex = 0;
static int no_iochans = 0;
static int no_iochans_total = 0;
 
static int iochan_use(int delta)
{
    int iochans;
    if (!g_mutex)
        yaz_mutex_create(&g_mutex);
    yaz_mutex_enter(g_mutex);
    no_iochans += delta;
    if (delta > 0)
        no_iochans_total += delta;
    iochans = no_iochans;
    yaz_mutex_leave(g_mutex);
    yaz_log(YLOG_DEBUG, "%s iochans=%d",
            delta == 0 ? "" : (delta > 0 ? "INC" : "DEC"), iochans);
    return iochans;
}
 
int iochans_count(void)
{
    return iochan_use(0);
}
 
int iochans_count_total(void)
{
    int total = 0;
    if (!g_mutex)
        return 0;
    yaz_mutex_enter(g_mutex);
    total = no_iochans_total;
    yaz_mutex_leave(g_mutex);
    return total;
}
#else
#define iochan_use(x)
#define iochans_count(x) 0
#define iochans_count_total(x) 0
#endif
 
struct iochan_man_s {
    IOCHAN channel_list;
    sel_thread_t sel_thread;
    int sel_fd;
    int no_threads;
    int log_level;
    YAZ_MUTEX iochan_mutex;
    int size_fds;
    int limit_fd;
    struct yaz_poll_fd *fds;
};
 
iochan_man_t iochan_man_create(int no_threads, int max_sockets)
{
    iochan_man_t man = xmalloc(sizeof(*man));
    man->channel_list = 0;
    man->sel_thread = 0; /* can't create sel_thread yet because we may fork */
    man->sel_fd = -1;
    man->no_threads = no_threads;
    man->log_level = yaz_log_module_level("iochan");
    man->iochan_mutex = 0;
    man->size_fds = 0;
    man->fds = 0;
    man->limit_fd = 0;
#if HAVE_GETRLIMIT
    {
        struct rlimit limit_data;
        getrlimit(RLIMIT_NOFILE, &limit_data);
        yaz_log(YLOG_LOG, "getrlimit NOFILE cur=%ld max=%ld",
                (long) limit_data.rlim_cur, (long) limit_data.rlim_max);
        man->limit_fd = limit_data.rlim_cur - 200;
    }
#endif
    if (max_sockets)
        man->limit_fd = max_sockets;
    yaz_log(YLOG_LOG, "iochan threads %d limit fd %d", no_threads,
            man->limit_fd);
    yaz_mutex_create(&man->iochan_mutex);
    return man;
}
 
IOCHAN iochan_destroy_real(IOCHAN chan)
{
    IOCHAN next = chan->next;
    if (chan->name)
        xfree(chan->name);
    xfree(chan);
    iochan_use(-1);
    return next;
}
 
void iochan_man_destroy(iochan_man_t *mp)
{
    if (*mp)
    {
        IOCHAN c;
        if ((*mp)->sel_thread)
            sel_thread_destroy((*mp)->sel_thread);
 
        yaz_mutex_enter((*mp)->iochan_mutex);
        c = (*mp)->channel_list;
        (*mp)->channel_list = NULL;
        yaz_mutex_leave((*mp)->iochan_mutex);
        while (c)
            c = iochan_destroy_real(c);
        yaz_mutex_destroy(&(*mp)->iochan_mutex);
        xfree((*mp)->fds);
        xfree(*mp);
        *mp = 0;
    }
}
 
int iochan_add(iochan_man_t man, IOCHAN chan, int slack)
{
    int r = 0, no_fds = 0;
    IOCHAN p;
 
    yaz_log(man->log_level, "iochan_add : chan=%p channel list=%p", chan,
            man->channel_list);
    yaz_mutex_enter(man->iochan_mutex);
    for (p = man->channel_list; p; p = p->next)
    {
        if (p->fd >= 0)
            no_fds++;
    }
    if (slack >= 0 && man->limit_fd > 0 && no_fds >= man->limit_fd - slack)
    {
        r = -1;
        yaz_log(YLOG_WARN, "max channels %d in use", no_fds);
    }
    else
    {
        chan->man = man;
        chan->next = man->channel_list;
        man->channel_list = chan;
    }
    yaz_mutex_leave(man->iochan_mutex);
    return r;
}
 
void iochan_destroy(IOCHAN chan)
{
    if (chan->man)
        chan->destroyed = 1;
    else
        iochan_destroy_real(chan);
}
 
IOCHAN iochan_create(int fd, IOC_CALLBACK cb, int flags, const char *name)
{
    IOCHAN new_iochan;
 
    if (!(new_iochan = (IOCHAN) xmalloc(sizeof(*new_iochan))))
        return 0;
    iochan_use(1);
    new_iochan->destroyed = 0;
    new_iochan->fd = fd;
    new_iochan->flags = flags;
    new_iochan->fun = cb;
    new_iochan->last_event = new_iochan->max_idle = 0;
    new_iochan->next = NULL;
    new_iochan->man = 0;
    new_iochan->thread_users = 0;
    new_iochan->name = name ? xstrdup(name) : 0;
    return new_iochan;
}
 
static void work_handler(void *work_data)
{
    IOCHAN p = work_data;
 
    yaz_log(p->man->log_level, "eventl: work begin chan=%p name=%s event=%d",
            p, p->name ? p->name : "", p->this_event);
 
    if (!p->destroyed && (p->this_event & EVENT_TIMEOUT))
        (*p->fun)(p, EVENT_TIMEOUT);
    if (!p->destroyed && (p->this_event & EVENT_INPUT))
        (*p->fun)(p, EVENT_INPUT);
    if (!p->destroyed && (p->this_event & EVENT_OUTPUT))
        (*p->fun)(p, EVENT_OUTPUT);
    if (!p->destroyed && (p->this_event & EVENT_EXCEPT))
        (*p->fun)(p, EVENT_EXCEPT);
 
    yaz_log(p->man->log_level, "eventl: work end chan=%p name=%s event=%d", p,
            p->name ? p->name : "", p->this_event);
}
 
static void run_fun(iochan_man_t man, IOCHAN p)
{
    if (man->sel_thread)
    {
        yaz_log(man->log_level,
                "eventl: work add chan=%p name=%s event=%d", p,
                p->name ? p->name : "", p->this_event);
        p->thread_users++;
        sel_thread_add(man->sel_thread, p);
    }
    else
        work_handler(p);
}
 
static int event_loop(iochan_man_t man, IOCHAN *iochans)
{
    do /* loop as long as there are active associations to process */
    {
        IOCHAN p, *nextp;
        IOCHAN start;
        IOCHAN inv_start;
        int res;
        struct yaz_poll_fd *fds;
        int i, no_fds = 0;
        int connection_fired = 0;
        int tv_sec = 300;
 
        yaz_mutex_enter(man->iochan_mutex);
        start = man->channel_list;
        yaz_mutex_leave(man->iochan_mutex);
        inv_start = start;
        for (p = start; p; p = p->next)
            no_fds++;
        if (man->sel_fd != -1)
            no_fds++;
        if (no_fds > man->size_fds)
        {
            man->size_fds = no_fds * 2;
            man->fds = xrealloc(man->fds, man->size_fds * sizeof(*man->fds));
        }
        fds = man->fds;
        i = 0;
        if (man->sel_fd != -1)
        {
            fds[i].fd = man->sel_fd;
            fds[i].input_mask = yaz_poll_read;
            fds[i].client_data = 0;
            i++;
        }
        for (p = start; p; p = p->next, i++)
        {
            p->poll_offset = i;
            fds[i].client_data = p;
            fds[i].fd = -1;
            fds[i].input_mask = 0;
            if (p->thread_users > 0)
                continue;
            if (p->max_idle && p->max_idle < tv_sec)
                tv_sec = p->max_idle;
            if (p->fd < 0)
                continue;
            if (p->flags & EVENT_INPUT)
                fds[i].input_mask |= yaz_poll_read;
            if (p->flags & EVENT_OUTPUT)
                fds[i].input_mask |= yaz_poll_write;
            if (p->flags & EVENT_EXCEPT)
                fds[i].input_mask |= yaz_poll_except;
            if (fds[i].input_mask)
                fds[i].fd = p->fd;
        }
        assert(i == no_fds);
        yaz_log(man->log_level, "yaz_poll begin tv_sec=%d nofds=%d", tv_sec,
                no_fds);
        res = yaz_poll(fds, no_fds, tv_sec, 0);
        yaz_log(man->log_level, "yaz_poll returned res=%d", res);
        if (res < 0)
        {
            if (errno == EINTR)
                continue;
            else
            {
                yaz_log(YLOG_ERRNO | YLOG_WARN, "poll");
                abort();
            }
        }
        if (man->sel_fd != -1)
        {
            i = 0;
            assert(fds[i].fd == man->sel_fd);
            if (fds[i].output_mask)
            {
                IOCHAN chan;
 
                yaz_log(man->log_level, "eventl: sel input on sel_fd=%d",
                        man->sel_fd);
                while ((chan = sel_thread_result(man->sel_thread)))
                {
                    yaz_log(man->log_level,
                            "eventl: got thread result chan=%p name=%s", chan,
                            chan->name ? chan->name : "");
                    chan->thread_users--;
                }
            }
        }
        if (man->log_level)
        {
            int no = 0;
            for (p = start; p; p = p->next)
                no++;
            yaz_log(man->log_level, "%d channels", no);
        }
        for (p = start; p; p = p->next)
        {
            time_t now = time(0);
            i = p->poll_offset;
 
            if (p->destroyed)
            {
                yaz_log(man->log_level,
                        "eventl: skip destroyed chan=%p name=%s", p,
                        p->name ? p->name : "");
                continue;
            }
            if (p->thread_users > 0)
            {
                yaz_log(man->log_level,
                        "eventl: skip chan=%p name=%s users=%d", p,
                        p->name ? p->name : "", p->thread_users);
                continue;
            }
            p->this_event = 0;
            if (p->max_idle && now - p->last_event > p->max_idle)
            {
                p->last_event = now;
                p->this_event |= EVENT_TIMEOUT;
            }
            if (fds[i].fd >= 0 && p->fd == fds[i].fd)
            {
                if (fds[i].output_mask & yaz_poll_read)
                {
                    p->last_event = now;
                    p->this_event |= EVENT_INPUT;
                }
                if (fds[i].output_mask & yaz_poll_write)
                {
                    p->last_event = now;
                    p->this_event |= EVENT_OUTPUT;
                }
                if (fds[i].output_mask & yaz_poll_except)
                {
                    p->last_event = now;
                    p->this_event |= EVENT_EXCEPT;
                }
            }
            /* only fire one Z39.50/SRU socket event.. except for timeout */
            if (p->this_event)
            {
                if (!(p->this_event & EVENT_TIMEOUT) &&
                    !strcmp(p->name, "connection_socket"))
                {
                    /* not a timeout and we have a Z39.50/SRU socket */
                    if (connection_fired == 0)
                        run_fun(man, p);
                    connection_fired++;
                }
                else
                    run_fun(man, p);
            }
        }
 
        assert(inv_start == start);
        yaz_mutex_enter(man->iochan_mutex);
        for (nextp = iochans; *nextp; )
        {
            IOCHAN p = *nextp;
            if (p->destroyed && p->thread_users == 0)
                *nextp = iochan_destroy_real(p);
            else
                nextp = &p->next;
        }
        yaz_mutex_leave(man->iochan_mutex);
    } while (*iochans);
    return 0;
}
 
void iochan_man_events(iochan_man_t man)
{
    if (man->no_threads > 0 && !man->sel_thread)
    {
        man->sel_thread = sel_thread_create(work_handler, 0 /*work_destroy */,
                &man->sel_fd, man->no_threads);
        yaz_log(man->log_level, "iochan_man_events. Using %d threads",
                man->no_threads);
    }
    event_loop(man, &man->channel_list);
}
 
/*
 * Local variables:
 * c-basic-offset: 4
 * c-file-style: "Stroustrup"
 * indent-tabs-mode: nil
 * End:
 * vim: shiftwidth=4 tabstop=8 expandtab
 */