port_user.c

Go to the documentation of this file.

/*
 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com)
 * Licensed under the GPL
 */

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <termios.h>
#include <unistd.h>
#include <netinet/in.h>
#include "chan_user.h"
#include <os.h>
#include "port.h"
#include <um_malloc.h>

struct port_chan {
    int raw;
    struct termios tt;
    void *kernel_data;
    char dev[sizeof("32768\0")];
};

static void *port_init(char *str, int device, const struct chan_opts *opts)
{
    struct port_chan *data;
    void *kern_data;
    char *end;
    int port;

    if (*str != ':') {
        printk(UM_KERN_ERR "port_init : channel type 'port' must "
               "specify a port number\n");
        return NULL;
    }
    str++;
    port = strtoul(str, &end, 0);
    if ((*end != '\0') || (end == str)) {
        printk(UM_KERN_ERR "port_init : couldn't parse port '%s'\n",
               str);
        return NULL;
    }

    kern_data = port_data(port);
    if (kern_data == NULL)
        return NULL;

    data = uml_kmalloc(sizeof(*data), UM_GFP_KERNEL);
    if (data == NULL)
        goto err;

    *data = ((struct port_chan) { .raw          = opts->raw,
                      .kernel_data  = kern_data });
    sprintf(data->dev, "%d", port);

    return data;
 err:
    port_kern_free(kern_data);
    return NULL;
}

static void port_free(void *d)
{
    struct port_chan *data = d;

    port_kern_free(data->kernel_data);
    kfree(data);
}

static int port_open(int input, int output, int primary, void *d,
             char **dev_out)
{
    struct port_chan *data = d;
    int fd, err;

    fd = port_wait(data->kernel_data);
    if ((fd >= 0) && data->raw) {
        CATCH_EINTR(err = tcgetattr(fd, &data->tt));
        if (err)
            return err;

        err = raw(fd);
        if (err)
            return err;
    }
    *dev_out = data->dev;
    return fd;
}

static void port_close(int fd, void *d)
{
    struct port_chan *data = d;

    port_remove_dev(data->kernel_data);
    os_close_file(fd);
}

const struct chan_ops port_ops = {
    .type       = "port",
    .init       = port_init,
    .open       = port_open,
    .close      = port_close,
    .read           = generic_read,
    .write      = generic_write,
    .console_write  = generic_console_write,
    .window_size    = generic_window_size,
    .free       = port_free,
    .winch      = 1,
};

int port_listen_fd(int port)
{
    struct sockaddr_in addr;
    int fd, err, arg;

    fd = socket(PF_INET, SOCK_STREAM, 0);
    if (fd == -1)
        return -errno;

    arg = 1;
    if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &arg, sizeof(arg)) < 0) {
        err = -errno;
        goto out;
    }

    addr.sin_family = AF_INET;
    addr.sin_port = htons(port);
    addr.sin_addr.s_addr = htonl(INADDR_ANY);
    if (bind(fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
        err = -errno;
        goto out;
    }

    if (listen(fd, 1) < 0) {
        err = -errno;
        goto out;
    }

    err = os_set_fd_block(fd, 0);
    if (err < 0)
        goto out;

    return fd;
 out:
    close(fd);
    return err;
}

struct port_pre_exec_data {
    int sock_fd;
    int pipe_fd;
};

static void port_pre_exec(void *arg)
{
    struct port_pre_exec_data *data = arg;

    dup2(data->sock_fd, 0);
    dup2(data->sock_fd, 1);
    dup2(data->sock_fd, 2);
    close(data->sock_fd);
    dup2(data->pipe_fd, 3);
    shutdown(3, SHUT_RD);
    close(data->pipe_fd);
}

int port_connection(int fd, int *socket, int *pid_out)
{
    int new, err;
    char *argv[] = { "/usr/sbin/in.telnetd", "-L",
             "/usr/lib/uml/port-helper", NULL };
    struct port_pre_exec_data data;

    new = accept(fd, NULL, 0);
    if (new < 0)
        return -errno;

    err = os_pipe(socket, 0, 0);
    if (err < 0)
        goto out_close;

    data = ((struct port_pre_exec_data)
        { .sock_fd          = new,
          .pipe_fd      = socket[1] });

    err = run_helper(port_pre_exec, &data, argv);
    if (err < 0)
        goto out_shutdown;

    *pid_out = err;
    return new;

 out_shutdown:
    shutdown(socket[0], SHUT_RDWR);
    close(socket[0]);
    shutdown(socket[1], SHUT_RDWR);
    close(socket[1]);
 out_close:
    close(new);
    return err;
}