collector.c

harvest是一个下载html网页得机器人

static char rcsid[] = "$Id: collector.c,v 2.2 2000/01/21 17:37:33 sxw Exp $";
/*
 *  collector.c -- Utility procs for add/delete/refresh objects in the Broker.
 *
 *  DEBUG: section  71, level 1         Broker collection routines
 *  AUTHOR: Harvest Derived (William G. Camargo, Darren Hardy)
 *
 *  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
 *    (http://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 "broker.h"
#include "log.h"

#define LUPDATE_SIZE MAXHOSTNAMELEN+30

/* Global variables */
extern char *Gather;
extern char *HName;
extern char *DIRpath;
extern char *ColConfig;
extern char *obj_desc;
extern int obj_desc_s;

int new_nobjs, up_nobjs, del_nobjs, ref_nobjs, recv_nobjs, ign_nobjs;
time_t max_update_time = 0;

GathererID *COL_gid = NULL;

/* Local functions */
static int COL_put_last_update();

/* -----------------------------------------------------------------
 * COL_UPD_Obj_begin() -- initialize a new summary object.
 * ----------------------------------------------------------------- */
FILE *COL_UPD_Obj_begin(entry)
     reg_t *entry;
{
	fd_t fd;

	if ((fd = SM_Create_Obj()) == ERROR) {
		errorlog("Collector: Cannot create a new object.\n");
		return NULL;
	}
	entry->FD = fd;
	return (SM_Write_Obj(fd));
}

/* ----------------------------------------------------------------- *
 * COL_Fill_Entry() -- fill in refresh rate and expiration times based
 * on given/default info.
 * ----------------------------------------------------------------- */
int COL_Fill_Entry(entry)
     reg_t *entry;
{
	/*
	 *  All Registry entries MUST have:
	 *      URL, Gatherer-Name, Gatherer-Host, Gatherer-Version,
	 *      and Update-Time
	 *  MD5's are optional, but may used in elimination searches.
	 */
	if (entry->url == NULL) {
		errorlog("%s%s: %s attribute is missing from object: %s\n",
		    COLLECT, ENTRY_ERR, "URL", entry->url);
		return ERROR;
	}
	if (entry->update_time == 0) {
		errorlog("%s%s: %s attribute is missing from object: %s\n",
		    COLLECT, ENTRY_ERR, "Update-Time", entry->url);
		return ERROR;
	}
	if (COL_gid->gn == NULL) {
		errorlog("%s%s: %s attribute is missing from object: %s\n",
		    COLLECT, ENTRY_ERR, "Gatherer-Name", entry->url);
		return ERROR;
	}
	if (COL_gid->gh == NULL) {
		errorlog("%s%s: %s attribute is missing from object: %s\n",
		    COLLECT, ENTRY_ERR, "Gatherer-Host", entry->url);
		return ERROR;
	}
	if (COL_gid->gv == NULL) {
		errorlog("%s%s: %s attribute is missing from object: %s\n",
		    COLLECT, ENTRY_ERR, "Gatherer-Version", entry->url);
		return ERROR;
	}
	COL_gid->GID = -1;
	entry->GID = RG_gid_register(COL_gid);
	if (entry->GID == -1) {
		errorlog("%s%s: illegal Gatherer ID for object.\n",
		    COLLECT, ENTRY_ERR);
		return ERROR;
	}
	/* Set default values */
	if (entry->lmt < 1)
		entry->lmt = 0;
	if (entry->refresh_rate < 1)
		entry->refresh_rate = (time_t) WEEK;

	return SUCCESS;
}

/* ----------------------------------------------------------------- *
 * COL_UPD_Obj_end() -- Add initialized summary object to the Broker.
 * ----------------------------------------------------------------- */
int COL_UPD_Obj_end(entry)
     reg_t *entry;
{
	reg_t *tmp;
	int updating = 0;

	/*
	 *  We want to see if the new object already matches any objects
	 *  in the current Registry.  If it does, then if the new object's
	 *  Update-Time is older than or the same as the Registry object's
	 *  Update-Time, then we ignore the new object.  Otherwise, we need
	 *  to replace the Registry objects with the new object.  We do this
	 *  by deleting the Registry objects, then adding the new object
	 *  to the Registry.  The RG_Cleaner() will run periodically
	 *  to compress the Registry.
	 *
	 *  If the new object is not in the Registry, then it's new
	 *  so we add it to the Registry.
	 */
	while ((tmp = RG_Object_Search_Entry(entry)) != NULL) {
		if (tmp->update_time >= entry->update_time) {
			(void) SM_Destroy_Obj(entry->FD);
			RG_Free_Entry(entry);
			ign_nobjs++;
			if (updating) del_nobjs++; /* There will be no update */
			return SUCCESS;
		} else {
			(void) RG_Clean_Entry(tmp);
			if (updating) del_nobjs++; /* One might be updated, */
			updating = 1;		   /* others are deleted.   */
		}
	}
	if (RG_Register(entry) == ERROR) {
		RG_Free_Entry(entry);
		return ERROR;
	}
	do_IND_New_Object(entry);
	LOGUPDATE(entry);
	if (updating) {
		up_nobjs++;
	} else
		new_nobjs++;
	return SUCCESS;
}

/* -----------------------------------------------------------------
 * COL_DEL_Obj() -- remove an object from the Broker.
 * ----------------------------------------------------------------- */
int COL_DEL_Obj(entry)
     reg_t *entry;
{
	reg_t *tmp;
	int err = SUCCESS;

	if ((tmp = RG_Object_Search_Entry(entry)) != NULL) {
		LOGDELETE(tmp);
		if (RG_Clean_Entry(tmp) == ERROR)
			err = ERROR;
		del_nobjs++;
	} else {
		ign_nobjs++;
	}
	RG_Free_Entry(entry);
	return (err);
}

/* -----------------------------------------------------------------
 * COL_REF_Obj -- update expiration time of an object.
 * ----------------------------------------------------------------- */
int COL_REF_Obj(entry)
     reg_t *entry;
{
	reg_t *tmp;

	/*
	 *  When refreshing the object, all we need to do is save
	 *  the new update_time, then write it to the Registry file.
	 */
	if ((tmp = RG_Object_Search_Entry(entry)) != NULL) {
		/* save new expiration time on disk */
		tmp->update_time = entry->update_time;
		replace_record(tmp);

		LOGREFRESH(entry);
		ref_nobjs++;
		RG_Free_Entry(entry);
		return SUCCESS;
	}
	ign_nobjs++;
	RG_Free_Entry(entry);
	return ERROR;
}

/* ----------------------------------------------------------------- *
 * COL_Save_Att() -- decide which attributes are needed in the registry
 * and save/free it
 * ----------------------------------------------------------------- */
int COL_Save_Att(wlk, entry)
     AVPair *wlk;
     reg_t *entry;
{
	num32 len;
	char *field_name;
	char *value;

	field_name = wlk->attribute;
	value = wlk->value;
	len = (num32) wlk->vsize;
	/* We can assume that these strcmp will only match once per object */
	if (strcmp(field_name, GATH_HOST) == 0) {
		COL_gid->gh = (char *) xmalloc(len + 1);
		memcpy(COL_gid->gh, value, len);
		COL_gid->gh[len] = '\0';
		COL_gid->ghs = len;
		return SUCCESS;
	} else if (strcmp(field_name, GATH_NAME) == 0) {
		COL_gid->gn = (char *) xmalloc(len + 1);
		memcpy(COL_gid->gn, value, len);
		COL_gid->gn[len] = '\0';
		COL_gid->gns = len;
		return SUCCESS;
	} else if (strcmp(field_name, GATH_VER) == 0) {
		COL_gid->gv = (char *) xmalloc(len + 1);
		memcpy(COL_gid->gv, value, len);
		COL_gid->gv[len] = '\0';
		COL_gid->gvs = len;
		return SUCCESS;
	} else if (strcmp(field_name, MD5) == 0) {
		entry->md5 = (char *) xmalloc(len + 1);
		memcpy(entry->md5, value, len);
		entry->md5[len] = '\0';
		entry->md5s = len;
		return SUCCESS;
	} else if (strcmp(field_name, LMT_A) == 0) {
		entry->lmt = (time_t) atol(value);
		if (entry->lmt < 1)
			entry->lmt = 0;
		return SUCCESS;
	} else if (strcmp(field_name, UPDATE_A) == 0) {
		entry->update_time = (time_t) atol(value);
		if (entry->update_time < 1)
			entry->update_time = 0;
		return SUCCESS;
	} else if (strcmp(field_name, TTL) == 0) {
		entry->ttl = (time_t) atol(value);
		if (entry->ttl < 1)
			entry->ttl = 0;
		return SUCCESS;
	} else if (strcmp(field_name, REFRESH_A) == 0) {
		entry->refresh_rate = (time_t) atol(value);
		if (entry->refresh_rate < 1)
			entry->refresh_rate = 0;
		return SUCCESS;
	} else if (strcasecmp(field_name, obj_desc) == 0) {
		if (entry->desc != NULL) {
			/* Ignore duplicate description field */
			return SUCCESS;
		}
#ifdef TRUNCATE_DESCRIPTIONS
		{
			/* Makes all descriptions one-line only */
			int maxdesc = 70, x;
			char *s;

			/* don't malloc too much; we truncate at maxdesc */
			x = ((maxdesc + 10) < len) ? (maxdesc + 10) : len;
			entry->desc = (char *) xmalloc(x + 1);
			memcpy(entry->desc, value, x);
			entry->desc[x] = '\0';
			/* See if chopping at the first newline will do it */
			if ((s = strchr(entry->desc, '\n')) != NULL)
				*s = '\0';
			if (strlen(entry->desc) > maxdesc) {
				/* we'd better just chop off the end */
				entry->desc[maxdesc - 1] = '\0';
				entry->desc[maxdesc - 2] = '.';
				entry->desc[maxdesc - 3] = '.';
				entry->desc[maxdesc - 4] = '.';
			}
			/* reassign buffer */
			s = xstrdup(entry->desc);
			xfree(entry->desc);
			entry->desc = s;
		}
#else
		entry->desc = (char *) xmalloc(len + 1);
		memcpy(entry->desc, value, len);
		entry->desc[len] = '\0';
#endif
		entry->descs = strlen(entry->desc);
		return SUCCESS;
	}
	return ERROR;
}

/* ----------------------------------------------------------------- *
 * COL_Normalize() do some thesaurus, normalization-- changes all
 * field names to lower case
 * ----------------------------------------------------------------- */
char *COL_Normalize_Name(name)
     char *name;
{
	UTIL_Make_Lower(name);
	return (name);
}

static int To_Gatherer[2];

/*
 *  COL_Create_Read_Pipe - creates a read pipe from the gather process.
 */
FILE *COL_Create_Read_Pipe(cmd)
     char *cmd;
{
	int pid;
	static FILE *fp;

	if (pipe(To_Gatherer) < 0) {
		log_errno("pipe");
		return (NULL);
	}
	/* need to use fork() rather than vfork() because of a memory leak */
	if ((pid = fork()) < 0) {
		log_errno("fork");
		return (NULL);
	}
	if (pid == 0) {		/* child */
		char *argv[64];

		/* simple parsing of the command string */
		memset(argv, '\0', sizeof(char *) * 64);
		parse_argv(argv, cmd);

		/* make 'gather' talk with the Broker */
		close(To_Gatherer[0]);
		dup2(To_Gatherer[1], 1);	/* stdout -> write pipe */

		/* close to prevent gather from getting the broker sockets */
		close_all_fds(3);

		/* stdin is /dev/null, stdout is pipe, stderr is broker.out */
		execvp(argv[0], argv);
		perror(argv[0]);
		_exit(1);
	}
	/* parent */
	close(To_Gatherer[1]);
	if ((fp = fdopen(To_Gatherer[0], "r")) == NULL) {
		errorlog("COL_Create_Read_Pipe: fdopen(%d, \"r\") failed.\n",
		    To_Gatherer[0]);
		close(To_Gatherer[0]);
		return (NULL);