On 7/13/06, Rahul Sharma <[EMAIL PROTECTED]> wrote:
/*    $OpenBSD: db.c,v 1.10 2004/09/16 18:35:42 deraadt Exp $    */

/*
 * Persistent database management routines for DHCPD.
 */

/*
 * Copyright (c) 1995, 1996 The Internet Software Consortium.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. Neither the name of The Internet Software Consortium 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 INTERNET SOFTWARE CONSORTIUM 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 INTERNET SOFTWARE CONSORTIUM 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.
 *
 * This software has been written for the Internet Software Consortium
 * by Ted Lemon <[EMAIL PROTECTED]> in cooperation with Vixie
 * Enterprises.  To learn more about the Internet Software Consortium,
 * see ``http://www.vix.com/isc''.  To learn more about Vixie
 * Enterprises, see ``http://www.vix.com''.
 */

#include "dhcpd.h"

FILE *db_file;
FILE *abc;
static int counting = 0;
static int count = 0;
time_t write_time;

/*
 * Write the specified lease to the current lease database file.
 */
int
write_lease(struct lease *lease)
{
    struct tm *t;
    char tbuf[64];
    int errors = 0;
    int i;

    if (counting)
        ++count;
    errno = 0;
    fprintf(db_file, "lease %s {\n", piaddr(lease->ip_addr));
    fprintf(abc,"%s\t",piaddr(lease->ip_addr));
    if (errno)
        ++errors;

    t = gmtime(&lease->starts);
    snprintf(tbuf, sizeof(tbuf), "%d %d/%02d/%02d %02d:%02d:%02d;",
        t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
        t->tm_hour, t->tm_min, t->tm_sec);

    errno = 0;
    fprintf(db_file, "\tstarts %s\n", tbuf);
    fprintf(abc, "%s\t", tbuf);
    if (errno)
        ++errors;

    t = gmtime(&lease->ends);
    snprintf(tbuf, sizeof(tbuf), "%d %d/%02d/%02d %02d:%02d:%02d;",
        t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
        t->tm_hour, t->tm_min, t->tm_sec);

    errno = 0;
    fprintf(db_file, "\tends %s", tbuf);
    fprintf(abc, "%s\t", tbuf);
    if (errno)
        ++errors;

    if (lease->hardware_addr.hlen) {
        errno = 0;
        fprintf(db_file, "\n\thardware %s %s;",
            hardware_types[lease->hardware_addr.htype],
            print_hw_addr(lease->hardware_addr.htype,
            lease->hardware_addr.hlen,
            lease->hardware_addr.haddr));

            fprintf(abc,"%s\n",
            print_hw_addr(lease->hardware_addr.htype,
            lease->hardware_addr.hlen,
            lease->hardware_addr.haddr));


        if (errno)
            ++errors;
    }

    if (lease->uid_len) {
        int j;

        errno = 0;
        fprintf(db_file, "\n\tuid %2.2x", lease->uid[0]);
        if (errno)
            ++errors;

        for (j = 1; j < lease->uid_len; j++) {
            errno = 0;
            fprintf(db_file, ":%2.2x", lease->uid[j]);
            if (errno)
                ++errors;
        }
        putc(';', db_file);
    }

    if (lease->flags & BOOTP_LEASE) {
        errno = 0;
        fprintf(db_file, "\n\tdynamic-bootp;");
        if (errno)
            ++errors;
    }

    if (lease->flags & ABANDONED_LEASE) {
        errno = 0;
        fprintf(db_file, "\n\tabandoned;");
        if (errno)
            ++errors;
    }

    if (lease->client_hostname) {
        for (i = 0; lease->client_hostname[i]; i++)
            if (lease->client_hostname[i] < 33 ||
                lease->client_hostname[i] > 126)
                goto bad_client_hostname;
        errno = 0;
        fprintf(db_file, "\n\tclient-hostname \"%s\";",
            lease->client_hostname);
        if (errno)
            ++errors;
    }

bad_client_hostname:
    if (lease->hostname) {
        for (i = 0; lease->hostname[i]; i++)
            if (lease->hostname[i] < 33 ||
                lease->hostname[i] > 126)
                goto bad_hostname;
        errno = 0;
        fprintf(db_file, "\n\thostname \"%s\";",
            lease->hostname);
        if (errno)
            ++errors;
    }

bad_hostname:
    errno = 0;
    fputs("\n}\n", db_file);
    if (errno)
        ++errors;

    if (errors)
        note("write_lease: unable to write lease %s",
            piaddr(lease->ip_addr));

    return (!errors);
}

/*
 * Commit any leases that have been written out...
 */
int
commit_leases(void)
{
    /*
     * Commit any outstanding writes to the lease database file. We need to
     * do this even if we're rewriting the file below, just in case the
     * rewrite fails.
     */
    if (fflush(db_file) == EOF) {
        note("commit_leases: unable to commit: %m");
        return (0);
    }

    if (fsync(fileno(db_file)) == -1) {
        note("commit_leases: unable to commit: %m");
        return (0);
    }

    /*
     * If we've written more than a thousand leases or if we haven't
     * rewritten the lease database in over an hour, rewrite it now.
     */
    if (count > 1000 || (count && cur_time - write_time > 3600)) {
        count = 0;
        write_time = cur_time;
        new_lease_file();
    }

    return (1);
}

void
db_startup(void)
{
    int db_fd,pqr;

    /* open lease file. once we dropped privs it has to stay open */
    db_fd = open(path_dhcpd_db, O_WRONLY|O_CREAT, 0664);
    if (db_fd == -1)
        error("Can't create new lease file: %m");
    if ((db_file = fdopen(db_fd, "w")) == NULL)
        error("Can't fdopen new lease file!");

    pqr = open("/var/db/log_dhcpd", O_WRONLY|O_CREAT, 0664);
    if (pqr == -1)
        error("Can't create new lease file: %m");
    if ((abc = fdopen(pqr, "w")) == NULL)
        error("Can't fdopen new lease file!");


    /* Read in the existing lease file... */
    read_leases();
    time(&write_time);

    new_lease_file();
}

void
new_lease_file(void)
{
    fflush(db_file);
    rewind(db_file);

    /*
     * Write an introduction so people don't complain about time being off.
     */
    fprintf(db_file, "# All times in this file are in UTC (GMT), "
        "not your local timezone.\n");
    fprintf(db_file, "# The format of this file is documented in "
        "the dhcpd.leases(5) manual page.\n\n");

    /* Write out all the leases that we know of... */
    counting = 0;
    write_leases();

    fflush(db_file);
    ftruncate(fileno(db_file), ftello(db_file));
    fsync(fileno(db_file));

    counting = 1;
}



On 7/13/06, Rahul Sharma <[EMAIL PROTECTED]> wrote:
>
> Hi all,
> I am using dhcpd on openBSD.
> I wanted to make a log file of my own from which enteries will never
> vanish.
> Though I can use dhcpd.leases and parse it to get the values but i wanted
> to it from the sourse itself.
>
> What i have done so far ->
>
> I have made changes in db.c
> 1. in function db_startup()
> 2.write_lease(struct lease *lease)
>
> I am attaching db.c file with changes with it.
> wherever u find "FILE *abc or  int pqr".i have added those lines
> it is compiling allright but is not writing into the file.
>
> Plz Help some one..........................
> Rahul

I notice that when you open the file we see:

void
db_startup(void)
{
  int db_fd,pqr; <-- FAIL

  /* open lease file. once we dropped privs it has to stay open */
  db_fd = open(path_dhcpd_db, O_WRONLY|O_CREAT, 0664);

That is, you are opening the file locally, so the other routines can't
get at it.

This is a nice exercise, but parsing from leases.conf is probably a
much better idea because it won't require constant patching as future
versions come out.

-Nick

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