cmd/vntsd/write.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */
#pragma ident   "%Z%%M% %I% %E% SMI"

/*
 * write thread - read from vcc console and  write to tcp client. There are one
 * writer and multiple readers per console. The first client who connects to
 * a console get write access.
 * Writer thread writes vcc data to all tcp clients that connected to
 * the console.
 */

#include <stdio.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <thread.h>
#include <synch.h>
#include <signal.h>
#include <assert.h>
#include <poll.h>
#include <syslog.h>
#include <libintl.h>
#include "vntsd.h"
#include "chars.h"

/* handle for writing all clients  */
typedef struct write_buf {
    uint_t  sz;     /* data size */
    char    *buf;
} write_buf_t;

/*
 * check the state of write thread. exit if no more client connects to the
 * console.
 */
static void
write_chk_status(vntsd_cons_t *consp, int status)
{

    if ((consp->status & VNTSD_CONS_DELETED) || (consp->clientpq == NULL)) {
        thr_exit(0);
    }

    switch (status) {
    case VNTSD_STATUS_VCC_IO_ERR:
        assert(consp->group != NULL);
        if (vntsd_vcc_err(consp) != VNTSD_STATUS_CONTINUE) {
            thr_exit(0);
        }
        break;
    case VNTSD_STATUS_INTR:
        thr_exit(0);
    default:
        break;

    }
}

/*
 * skip_terminal_null()
 * scan terminal null character sequence (0x5e 0x40)
 * return number of characters in the buf after skipping terminal null
 * sequence. buf size must be at least sz+1.
 */
static int
skip_terminal_null(char *buf, int sz)
{
    int     i, j;
    static int  term_null_seq = 0;

    assert(sz >= 0);

    if (term_null_seq) {
        /* skip 0x5e previously */
        term_null_seq = 0;

        if (buf[0] != 0x40) {
            /* not terminal null sequence put 0x5e back */
            for (i = sz; i > 0; i--) {
                buf[i] = buf[i-1];
            }

            buf[0] = 0x5e;

            sz++;
        } else {
            /* skip terminal null sequence */
            sz--;

            if (sz == 0) {
                return (sz);
            }

            for (i = 0; i < sz; i++) {
                buf[i] = buf[i+1];
            }
        }
    }

    for (; ; ) {
        for (i = 0; i < sz; i++) {
            if (buf[i]  == '\0') {
                return (i);
            }

            if (buf[i] == 0x5e) {
                /* possible terminal null sequence */
                if (i == sz -1) {
                    /* last character in buffer */
                    term_null_seq = 1;
                    sz--;
                    buf[i] = 0;
                    return (sz);
                }

                if (buf[i+1] == 0x40) {
                    /* found terminal null sequence */
                    sz -= 2;
                    for (j = i; j < sz -i; j++) {
                        buf[j] = buf[j+2];
                    }
                    break;
                }

                if (buf[i+1] == '\0') {
                    buf[i] = 0;
                    term_null_seq = 1;
                    return (i);
                }

            }
        }

        if (i == sz) {
            /* end of scan */
            return (sz);
        }
    }
}

/* read data from vcc */
static int
read_vcc(vntsd_cons_t *consp, char *buf, ssize_t *sz)
{
    /* read from vcc */
    *sz = read(consp->vcc_fd, buf, VNTSD_MAX_BUF_SIZE);

    if (errno == EINTR) {
        return (VNTSD_STATUS_INTR);
    }

    if ((*sz > 0)) {
        return (VNTSD_SUCCESS);
    }
    return (VNTSD_STATUS_VCC_IO_ERR);
}

/*
 * write to a client
 * this function is passed as a parameter to vntsd_que_find.
 * for each client that connected to the console, vntsd_que_find
 * applies this function.
 */
static boolean_t
write_one_client(vntsd_client_t *clientp, write_buf_t *write_buf)
{
    int rv;

    rv = vntsd_write_client(clientp, write_buf->buf, write_buf->sz);
    if (rv != VNTSD_SUCCESS) {
        (void) mutex_lock(&clientp->lock);
        clientp->status |= VNTSD_CLIENT_IO_ERR;
        assert(clientp->cons);
        (void) thr_kill(clientp->cons_tid, NULL);
        (void) mutex_unlock(&clientp->lock);
    }
    return (B_FALSE);

}

/* vntsd_write_thread() */
void*
vntsd_write_thread(vntsd_cons_t *consp)
{
    char        buf[VNTSD_MAX_BUF_SIZE+1];
    int     sz;
    int     rv;
    write_buf_t write_buf;

    D1(stderr, "t@%d vntsd_write@%d\n", thr_self(), consp->vcc_fd);

    assert(consp);
    write_chk_status(consp, VNTSD_SUCCESS);

    for (; ; ) {
        bzero(buf,  VNTSD_MAX_BUF_SIZE +1);

        /* read data */
        rv = read_vcc(consp, buf, &sz);

        write_chk_status(consp, rv);

        if (sz <= 0) {
            continue;
        }

        /* has data */
        if ((sz = skip_terminal_null(buf, sz)) == 0) {
            /* terminal null sequence */
            continue;
        }

        write_buf.sz = sz;
        write_buf.buf = buf;

        /*
         * output data to all clients connected
         * to this console
         */

        (void) mutex_lock(&consp->lock);
        (void) vntsd_que_find(consp->clientpq,
            (compare_func_t)write_one_client, &write_buf);
        (void) mutex_unlock(&consp->lock);

        write_chk_status(consp, VNTSD_SUCCESS);

    }

    /*NOTREACHED*/
    return (NULL);
}