Archipelago » blktap-utils

/*

 * Copyright (c) 2010, Citrix 

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *     * Redistributions of source code must retain the above copyright

 *       notice, this list of conditions and the following disclaimer.

 *     * Redistributions in binary form must reproduce the above copyright

 *       notice, this list of conditions and the following disclaimer in the

 *       documentation and/or other materials provided with the distribution.

 *     * Neither the name of XenSource Inc. nor the names of its contributors

 *       may be used to endorse or promote products derived from this software

 *       without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER

 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include <stdio.h>

#include <string.h>

#include <unistd.h>

#include <sys/mman.h>

#include "tap-ctl.h"

int

_tap_ctl_stats_connect_and_send(pid_t pid, int minor)

{

        struct timeval timeout = { .tv_sec = 10, .tv_usec = 0 };

        tapdisk_message_t message;

        int sfd, err;

        err = tap_ctl_connect_id(pid, &sfd);

        if (err)

                return err;

        memset(&message, 0, sizeof(message));

        message.type   = TAPDISK_MESSAGE_STATS;

        message.cookie = minor;

        err = tap_ctl_write_message(sfd, &message, &timeout);

        if (err)

                return err;

        return sfd;

}

ssize_t

tap_ctl_stats(pid_t pid, int minor, char *buf, size_t size)

{

        tapdisk_message_t message;

        int sfd, err;

        size_t len;

        sfd = _tap_ctl_stats_connect_and_send(pid, minor);

        if (sfd < 0)

                return sfd;

        err = tap_ctl_read_message(sfd, &message, NULL);

        if (err)

                return err;

        len= message.u.info.length;

        if (len < 0) {

                err = len;

                goto out;

        }

        if (size < len + 1)

                len = size - 1;

        err = tap_ctl_read_raw(sfd, buf, len, NULL);

        if (err)

                goto out;

        buf[len] = 0;

out:

        close(sfd);

        return err;

}

int

tap_ctl_stats_fwrite(pid_t pid, int minor, FILE *stream)

{

        tapdisk_message_t message;

        int sfd = -1, prot, flags, err;

        size_t len, bufsz;

        char *buf = MAP_FAILED;

        prot  = PROT_READ|PROT_WRITE;

        flags = MAP_ANONYMOUS|MAP_PRIVATE;

        bufsz = sysconf(_SC_PAGE_SIZE);

        buf = mmap(NULL, bufsz, prot, flags, -1, 0);

        if (buf == MAP_FAILED) {

                buf = NULL;

                err = -ENOMEM;

                goto out;

        }

        sfd = _tap_ctl_stats_connect_and_send(pid, minor);

        if (sfd < 0) {

                err = sfd;

                goto out;

        }

        err = tap_ctl_read_message(sfd, &message, NULL);

        if (err)

                goto out;

        len = message.u.info.length;

        err = len;

        if (len < 0)

                goto out;

        while (len) {

                fd_set rfds;

                size_t in, out;

                int n;

                FD_ZERO(&rfds);

                FD_SET(sfd, &rfds);

                n = select(sfd + 1, &rfds, NULL, NULL, NULL);

                err = n;

                if (n < 0)

                        goto out;

                in = read(sfd, buf, bufsz);

                err = in;

                if (in <= 0)

                        goto out;

                len -= in;

                out = fwrite(buf, in, 1, stream);

                if (out != in) {

                        err = -errno;

                        goto out;

                }

        }

out:

        if (sfd >= 0)

                close(sfd);

        if (buf != MAP_FAILED)

                munmap(buf, bufsz);

        return err;

}