gopherenum-breadth.c

harvest是一个下载html网页得机器人

static char rcsid[] = "$Id: gopherenum-breadth.c,v 2.5 2000/02/03 12:45:56 sxw Exp $";
/*
 *  gopherenum-breadth.c - RootNode URL enumerator for Gopher URLs
 *
 *  Usage: gopherenum-breadth gopher-URL
 *
 *  Outputs the following format:
 *
 *      URL of tree root
 *      URL <tab> md5
 *      ...
 *      URL <tab> md5
 *
 *  DEBUG: section  43, level 1, 5, 9   Gatherer enumeration for Gopher
 *  AUTHOR: Harvest derived
 *
 *  Harvest Indexer http://harvest.sourceforge.net/
 *  -----------------------------------------------
 *
 *  The Harvest Indexer is a continued development of code developed by
 *  the Harvest Project. Development is carried out by numerous individuals
 *  in the Internet community, and is not officially connected with the
 *  original Harvest Project or its funding sources.
 *
 *  Please mail [e-mail] if you are interested in participating
 *  in the development effort.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*  ----------------------------------------------------------------------
 *  Copyright (c) 1994, 1995.  All rights reserved.
 *
 *    The Harvest software was developed by the Internet Research Task
 *    Force Research Group on Resource Discovery (IRTF-RD):
 *
 *          Mic Bowman of Transarc Corporation.
 *          Peter Danzig of the University of Southern California.
 *          Darren R. Hardy of the University of Colorado at Boulder.
 *          Udi Manber of the University of Arizona.
 *          Michael F. Schwartz of the University of Colorado at Boulder.
 *          Duane Wessels of the University of Colorado at Boulder.
 *
 *    This copyright notice applies to software in the Harvest
 *    ``src/'' directory only.  Users should consult the individual
 *    copyright notices in the ``components/'' subdirectories for
 *    copyright information about other software bundled with the
 *    Harvest source code distribution.
 *
 *  TERMS OF USE
 *
 *    The Harvest software may be used and re-distributed without
 *    charge, provided that the software origin and research team are
 *    cited in any use of the system.  Most commonly this is
 *    accomplished by including a link to the Harvest Home Page
 *    (gopher://harvest.cs.colorado.edu/) from the query page of any
 *    Broker you deploy, as well as in the query result pages.  These
 *    links are generated automatically by the standard Broker
 *    software distribution.
 *
 *    The Harvest software is provided ``as is'', without express or
 *    implied warranty, and with no support nor obligation to assist
 *    in its use, correction, modification or enhancement.  We assume
 *    no liability with respect to the infringement of copyrights,
 *    trade secrets, or any patents, and are not responsible for
 *    consequential damages.  Proper use of the Harvest software is
 *    entirely the responsibility of the user.
 *
 *  DERIVATIVE WORKS
 *
 *    Users may make derivative works from the Harvest software, subject
 *    to the following constraints:
 *
 *      - You must include the above copyright notice and these
 *        accompanying paragraphs in all forms of derivative works,
 *        and any documentation and other materials related to such
 *        distribution and use acknowledge that the software was
 *        developed at the above institutions.
 *
 *      - You must notify IRTF-RD regarding your distribution of
 *        the derivative work.
 *
 *      - You must clearly notify users that your are distributing
 *        a modified version and not the original Harvest software.
 *
 *      - Any derivative product is also subject to these copyright
 *        and use restrictions.
 *
 *    Note that the Harvest software is NOT in the public domain.  We
 *    retain copyright, as specified above.
 *
 *  HISTORY OF FREE SOFTWARE STATUS
 *
 *    Originally we required sites to license the software in cases
 *    where they were going to build commercial products/services
 *    around Harvest.  In June 1995 we changed this policy.  We now
 *    allow people to use the core Harvest software (the code found in
 *    the Harvest ``src/'' directory) for free.  We made this change
 *    in the interest of encouraging the widest possible deployment of
 *    the technology.  The Harvest software is really a reference
 *    implementation of a set of protocols and formats, some of which
 *    we intend to standardize.  We encourage commercial
 *    re-implementations of code complying to this set of standards.
 *
 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <memory.h>
#include <string.h>
#include <signal.h>
#include <gdbm.h>
#include "util.h"
#include "url.h"
#define PUBLIC extern
#include "filter.h"

typedef struct _list_t {
    void *ptr;
    int depth;
    struct _list_t *next;
} list_t;

list_t *head = NULL;
list_t **Tail = NULL;

/* define HOST_COUNT_IP to 'count' visited hosts based on IP, not the   */
/* given hostname.  This way aliased machines will be properly          */
/* enumerated                                                           */
#define HOST_COUNT_IP

/* Global variables */
int max_depth = 0;
int cur_depth = 0;
int depth_hist[100];

/* Local variables */
static int url_max = 0;
static int nurls = 0;
static int host_max = 0;
static int nhosts = 0;
static char *tree_root = NULL;
static char *urldb_filename = NULL;
static char *hostdb_filename = NULL;
static char *md5db_filename = NULL;
static GDBM_FILE urldbf = NULL;
static GDBM_FILE hostdbf = NULL;
static GDBM_FILE md5dbf = NULL;

static FILE *not_visited = NULL;

/* Local functions */
static void usage();
static void mark_failed();
static void mark_retrieved();
static void sigdie();
static int url_in_db();
static int md5_in_db();
static int gopher_enum();

extern int RobotsTxtCheck _PARAMS((URL *));

list_t *add_to_list(url, depth)
     char *url;
     int depth;
{
    list_t *l = NULL;

    l = (list_t *) xmalloc(sizeof(list_t));
    l->ptr = (void *) xstrdup(url);
    l->next = (list_t *) NULL;
    l->depth = depth;
    *Tail = l;
    Tail = &(l->next);
    return l;
}

list_t *free_from_list(l)
     list_t *l;
{
    list_t *r = NULL;

    r = l->next;
    xfree(l->ptr);
    xfree(l);
    return r;
}

/* ---------------------------------------------------------------------- */

/*
 *  mark_failed() - Mark that a URL failed to be retrieved, so that the
 *  enumerator doesn't try it again. This option may not be wanted by
 *  some users and so should be configurable.
 */
static void mark_failed(URL *up) {
    datum k,d;

    Debug(43, 9, ("mark_failed: url='%s'",up->url));

    k.dptr = xstrdup(up->url);
    k.dsize = strlen(k.dptr) + 1;
    d.dptr = xstrdup("FailedAccess");
    d.dsize = strlen(d.dptr) + 1;

    if (!gdbm_exists(urldbf, k) && gdbm_store(urldbf, k, d, GDBM_INSERT))
        fatal("GDBM URLDB: %s: %s", k.dptr, gdbm_strerror(gdbm_errno));

    xfree(k.dptr);
    xfree(d.dptr);
}

/*
 *  mark_retrieved() - Mark that the given URL was successfully retrieved,
 *  so that the URL is not retrieved again.  This prevents cycles in the
 *  enumeration.
 */
static void mark_retrieved(up)
     URL *up;
{
    datum k, d;

    Debug(43, 9, ("mark_retrieved: url='%s', md5='%s'\n", up->url, up->md5));

    k.dptr = xstrdup(up->url);
    k.dsize = strlen(k.dptr) + 1;
    d.dptr = xstrdup(up->md5);
    d.dsize = strlen(d.dptr) + 1;

    if (!gdbm_exists(urldbf, k) && gdbm_store(urldbf, k, d, GDBM_INSERT))
	fatal("GDBM URLDB: %s: %s", k.dptr, gdbm_strerror(gdbm_errno));
    if (!gdbm_exists(md5dbf, d) && gdbm_store(md5dbf, d, k, GDBM_INSERT))
	fatal("GDBM MD5DB: %s: %s", k.dptr, gdbm_strerror(gdbm_errno));

    xfree(k.dptr);
    xfree(d.dptr);

    /* Print URL to stdout to enumerate; flush to keep pipe moving */
    fprintf(stdout, "%s\t%s\n", up->url, up->md5);	/* URL <tab> MD5 */
    fflush(stdout);

    if (nurls++ >= url_max) {
	Log("Truncating RootNode %s at %d LeafNode URLs\n",
	    tree_root, url_max);
	url_close(up);
	up = NULL;
	sigdie(0);
    }
}

/*
 *  url_in_db() - check to see if the URL is in the database
 */
static int url_in_db(url)
     char *url;
{
    datum k;
    int r;

    Debug(43, 9, ("url_in_db: checking for url='%s'\n", url));

    k.dptr = xstrdup(url);
    k.dsize = strlen(k.dptr) + 1;
    r = gdbm_exists(urldbf, k);
    xfree(k.dptr);
    return (r);
}

/*
 *  md5_in_db() - check to see if the MD5 is in the database
 */
static int md5_in_db(md5)
     char *md5;
{
    datum k;
    int r;

    k.dptr = xstrdup(md5);
    k.dsize = strlen(k.dptr) + 1;
    r = gdbm_exists(md5dbf, k);
    xfree(k.dptr);
    return (r);
}

/*
 *  host_in_db() - check to see if the host is in the database
 */
static int host_in_db(host)
     char *host;
{
    datum k;
    int r;
#ifdef HOST_COUNT_IP
    Host *h;

    h = get_host(host);
    if (!h)
	return 0;
    k.dptr = xstrdup(h->dotaddr);
#else
    k.dptr = xstrdup(host);
#endif
    k.dsize = strlen(k.dptr) + 1;
    r = gdbm_exists(hostdbf, k);
    xfree(k.dptr);
    return (r);
}

/*
 *  visit_server() - Determine if we should visit the server.  Return
 *  zero if we should not process the URL; otherwise, return non-zero.
 */
static int visit_server(up)
     URL *up;
{
    datum k, d;
#ifdef HOST_COUNT_IP
    Host *h = NULL;
#endif

    if (host_in_db(up->host))	/* Host is already in the db */
	return (1);
    if (++nhosts > host_max)
	return (0);

#ifdef HOST_COUNT_IP
    h = get_host(up->host);
    if (!h)
	return (0);
    k.dptr = xstrdup(h->dotaddr);
#else
    k.dptr = xstrdup(up->host);
#endif
    k.dsize = strlen(k.dptr) + 1;
    d.dptr = xstrdup(up->url);
    d.dsize = strlen(d.dptr) + 1;

    if (gdbm_store(hostdbf, k, d, GDBM_INSERT))
	fatal("GDBM HOSTDB: %s: %s", k.dptr, gdbm_strerror(gdbm_errno));
    xfree(k.dptr);
    xfree(d.dptr);
    return (1);
}

int url_is_allowed(url)
     char *url;
{
    URL *tup = NULL;