io-mainloop.c

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/*
 *
 *  BlueZ - Bluetooth protocol stack for Linux
 *
 *  Copyright (C) 2012-2014  Intel Corporation. All rights reserved.
 *
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library 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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <unistd.h>
#include <errno.h>
#include <sys/socket.h>

#include "mainloop.h"
#include "util.h"
#include "io.h"

struct io {
    int ref_count;                          
    int fd;                                 
    uint32_t events;                        
    bool close_on_destroy;                  
    io_callback_func_t read_callback;       
    io_destroy_func_t read_destroy;         
    void *read_data;                        
    io_callback_func_t write_callback;      
    io_destroy_func_t write_destroy;        
    void *write_data;                       
    io_callback_func_t disconnect_callback; 
    io_destroy_func_t disconnect_destroy;   
    void *disconnect_data;                  
};

static struct io *io_ref(struct io *io)
{
    if (!io)
        return NULL;

    __sync_fetch_and_add(&io->ref_count, 1);

    return io;
}

static void io_unref(struct io *io)
{
    if (!io)
        return;

    if (__sync_sub_and_fetch(&io->ref_count, 1))
        return;

    free(io);
}

static void io_cleanup(void *user_data)
{
    struct io *io = user_data;

    if (io->write_destroy)
        io->write_destroy(io->write_data);

    if (io->read_destroy)
        io->read_destroy(io->read_data);

    if (io->disconnect_destroy)
        io->disconnect_destroy(io->disconnect_data);

    if (io->close_on_destroy)
        close(io->fd);

    io->fd = -1;
}

static void io_callback(int fd, uint32_t events, void *user_data)
{
    struct io *io = user_data;

    io_ref(io);

    if ((events & (EPOLLRDHUP | EPOLLHUP | EPOLLERR))) {
        io->read_callback = NULL;
        io->write_callback = NULL;

        if (!io->disconnect_callback) {
            mainloop_remove_fd(io->fd);
            io_unref(io);
            return;
        }

        if (!io->disconnect_callback(io, io->disconnect_data)) {
            if (io->disconnect_destroy)
                io->disconnect_destroy(io->disconnect_data);

            io->disconnect_callback = NULL;
            io->disconnect_destroy = NULL;
            io->disconnect_data = NULL;

            io->events &= ~EPOLLRDHUP;

            mainloop_modify_fd(io->fd, io->events);
        }
    }

    if ((events & EPOLLIN) && io->read_callback) {
        if (!io->read_callback(io, io->read_data)) {
            if (io->read_destroy)
                io->read_destroy(io->read_data);

            io->read_callback = NULL;
            io->read_destroy = NULL;
            io->read_data = NULL;

            io->events &= ~EPOLLIN;

            mainloop_modify_fd(io->fd, io->events);
        }
    }

    if ((events & EPOLLOUT) && io->write_callback) {
        if (!io->write_callback(io, io->write_data)) {
            if (io->write_destroy)
                io->write_destroy(io->write_data);

            io->write_callback = NULL;
            io->write_destroy = NULL;
            io->write_data = NULL;

            io->events &= ~EPOLLOUT;

            mainloop_modify_fd(io->fd, io->events);
        }
    }

    io_unref(io);
}

struct io *io_new(int fd)
{
    struct io *io;

    if (fd < 0)
        return NULL;

    io = new0(struct io, 1);
    if (!io)
        return NULL;

    io->fd = fd;
    io->events = 0;
    io->close_on_destroy = false;

    if (mainloop_add_fd(io->fd, io->events, io_callback,
                        io, io_cleanup) < 0) {
        free(io);
        return NULL;
    }

    return io_ref(io);
}

void io_destroy(struct io *io)
{
    if (!io)
        return;

    io->read_callback = NULL;
    io->write_callback = NULL;
    io->disconnect_callback = NULL;

    mainloop_remove_fd(io->fd);

    io_unref(io);
}

int io_get_fd(struct io *io)
{
    if (!io)
        return -ENOTCONN;

    return io->fd;
}

bool io_set_close_on_destroy(struct io *io, bool do_close)
{
    if (!io)
        return false;

    io->close_on_destroy = do_close;

    return true;
}

bool io_set_read_handler(struct io *io, io_callback_func_t callback,
                void *user_data, io_destroy_func_t destroy)
{
    uint32_t events;

    if (!io || io->fd < 0)
        return false;

    if (io->read_destroy)
        io->read_destroy(io->read_data);

    if (callback)
        events = io->events | EPOLLIN;
    else
        events = io->events & ~EPOLLIN;

    io->read_callback = callback;
    io->read_destroy = destroy;
    io->read_data = user_data;

    if (events == io->events)
        return true;

    if (mainloop_modify_fd(io->fd, events) < 0)
        return false;

    io->events = events;

    return true;
}

bool io_set_write_handler(struct io *io, io_callback_func_t callback,
                void *user_data, io_destroy_func_t destroy)
{
    uint32_t events;

    if (!io || io->fd < 0)
        return false;

    if (io->write_destroy)
        io->write_destroy(io->write_data);

    if (callback)
        events = io->events | EPOLLOUT;
    else
        events = io->events & ~EPOLLOUT;

    io->write_callback = callback;
    io->write_destroy = destroy;
    io->write_data = user_data;

    if (events == io->events)
        return true;

    if (mainloop_modify_fd(io->fd, events) < 0)
        return false;

    io->events = events;

    return true;
}

bool io_set_disconnect_handler(struct io *io, io_callback_func_t callback,
                void *user_data, io_destroy_func_t destroy)
{
    uint32_t events;

    if (!io || io->fd < 0)
        return false;

    if (io->disconnect_destroy)
        io->disconnect_destroy(io->disconnect_data);

    if (callback)
        events = io->events | EPOLLRDHUP;
    else
        events = io->events & ~EPOLLRDHUP;

    io->disconnect_callback = callback;
    io->disconnect_destroy = destroy;
    io->disconnect_data = user_data;

    if (events == io->events)
        return true;

    if (mainloop_modify_fd(io->fd, events) < 0)
        return false;

    io->events = events;

    return true;
}

ssize_t io_send(struct io *io, const struct iovec *iov, int iovcnt)
{
    ssize_t ret;

    if (!io || io->fd < 0)
        return -ENOTCONN;

    do {
        ret = writev(io->fd, iov, iovcnt);
    } while (ret < 0 && errno == EINTR);

    if (ret < 0)
        return -errno;

    return ret;
}

bool io_shutdown(struct io *io)
{
    if (!io || io->fd < 0)
        return false;

    return shutdown(io->fd, SHUT_RDWR) == 0;
}