url.c

harvest是一个下载html网页得机器人

static char rcsid[] = "$Id: url.c,v 2.3 2000/01/21 17:37:33 sxw Exp $";
/*
 *  url.c - URL processing code
 *
 *  DEBUG: section  20, level 1         Common liburl URL processing
 *  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
 *    (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 <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <ctype.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <errno.h>
#include "util.h"
#include "url.h"
#ifdef USE_CCACHE
#include "ccache.h"
#endif

#define BIG_BUFSIZ (BUFSIZ<<3)

/* Global variables */
int liburl_conform_rfc1738 = 0;
int liburl_sleep_time;
#ifdef USE_LOCAL_CACHE
int use_local_cache = 1;
#else
int use_local_cache = 0;
#endif

/* Local Functions */
static void Tolower();
static void remove_dot();
static void remove_dotdot();
static URL *url_parse();
static char *shsafe_path();
static void get_lmt();

#ifdef OLD_CODE
static int compare_fullhost();
#endif

/* NOTE these rely on the order of 'enum url_types' in ../include/url.h */
struct _url_table url_table[] = {
	{
		"unknown", 0, 0
	},			/* URL_UNKNOWN, */
	{
		"file", 0, 0
	},			/* URL_FILE,    */
	{
		"ftp", 21, ftp_get
	},			/* URL_FTP,     */
	{
		"gopher", 70, gopher_get
	},			/* URL_GOPHER,  */
	{
		"http", 80, http_get
	},			/* URL_HTTP,    */
	{
		"news", 119, news_get
	},			/* URL_NEWS,    */
	{
		"nop", 0, 0
	},			/* URL_NOP,     */
	{
		"telnet", 25, 0
	},			/* URL_TELNET,  */
	{
		"wais", 0, 0
	},			/* URL_WAIS,    */
	{
		"x-", 0, 0
	},			/* URL_X,       */
	{
		"mailto", 0, 0
	},			/* URL_MAILTO,  */
};

static int init_called = 0;

struct local_trans_table {
	char *from;
	char *to;
	struct local_trans_table *next;
};
static struct local_trans_table *LocalTransTable = NULL;


void url_initLocalServers()
{
	FILE *fp = NULL;
	char *from = NULL;
	char *to = NULL;
	char *t = NULL;
	char *buf = NULL;
	struct local_trans_table *x;

	LocalTransTable = NULL;
	if ((t = getenv("HARVEST_URL_LOCAL_MAPPINGS")) == NULL)
		return;
	Debug(20, 1, ("url_initLocalServers: OPEN URLTABLE: %s\n", t));
	if ((fp = fopen(t, "r")) == NULL)
		return;
	from = xmalloc(BUFSIZ);
	to = xmalloc(BUFSIZ);
	buf = xmalloc(BUFSIZ);
	while (fgets(buf, BUFSIZ, fp)) {
		if ((t = strchr(buf, '\n')))
			*t = '\0';
		if (sscanf(buf, "%s %s", from, to) != 2)
			continue;
		Debug(20, 1, ("url_initLocalServers: READ URLTABLE: %s --> %s\n",
			from, to));
		x = (struct local_trans_table *)
		    xmalloc(sizeof(struct local_trans_table));
		x->from = xstrdup(from);
		x->to = xstrdup(to);
		x->next = LocalTransTable;
		LocalTransTable = x;
	}
	fclose(fp);
	xfree(from);
	xfree(to);
	xfree(buf);
}


void init_url()
{
	char *s;

	if (init_called)
		return;

	init_called = 1;
	liburl_sleep_time = 1;	/* hard-coded default */
	if ((s = getenv("HARVEST_URL_DELAY")) != NULL)
		liburl_sleep_time = atoi(s);
	if (liburl_sleep_time < 0)
		liburl_sleep_time = 1;
	if ((s = getenv("HARVEST_GATHERER_DBS")) != NULL)
		urldb_init(s);

#ifdef USE_LOCAL_CACHE
	if (use_local_cache)
		init_cache();
#endif
#ifdef USE_CCACHE
	url_initCache(10, 600);
#endif
	url_initLocalServers();
}


void url_purge()
{
	if (!init_called)
		init_url();
#ifdef USE_LOCAL_CACHE
	if (use_local_cache)
		expire_cache();
#endif
}


void finish_url()
{
#ifdef USE_LOCAL_CACHE
	if (use_local_cache)
		finish_cache();
#endif
#ifdef USE_CCACHE
	url_shutdowncache();
#endif
}


/*
 *  url_open() - Parses and initializes the given url into a URL structure.
 *  Returns a pointer to the structure on success; or returns NULL if the
 *  URL is not parseable, or if the URL's host is not valid.
 */
URL *url_open(url)
     char *url;
{
	static URL *up = NULL;
	static char buf[BUFSIZ];
	struct local_trans_table *l;
	char *s, *local_filename = NULL;
	char local_filename_buf[1024];
	struct stat sb;

	Debug(20, 1, ("url_open: %s\n", url));

	if (!init_called) {
		init_url();
	}
	if ((up = url_parse(url)) == NULL) {
		url_close(up);
		return (NULL);
	}
	for (l = LocalTransTable; !local_filename && l; l = l->next) {
		if (strchr(l->from, '*')) {
			/* Do wildcard based mapping */
			if (url_matchAndSub(l->from, up->url, l->to, local_filename_buf,
				1024) == 0 ) {
				Debug(20, 1, ("Local Mapping: '%s' matched '%s'\n", up->url,
					l->from));
				local_filename = (char *) xmalloc(strlen(local_filename_buf)+1);
				strcpy(local_filename, local_filename_buf);
				Debug(20, 1, ("Mapped to: '%s'\n", local_filename));
			}
		} else if (!strncasecmp(up->url, l->from, strlen(l->from))) {
			Debug(20, 1, ("Local Mapping: '%s' matched '%s'\n",
				up->url, l->from));
			s = up->url + strlen(l->from);
			local_filename = (char *) xmalloc(strlen(l->to) +
				strlen(s) + 1);
			sprintf(local_filename, "%s%s", l->to, s);
		}
		if (local_filename) {
			int fd=-1;

			/* no HTTP involved, so unescape URI */
			rfc1738_unescape(local_filename);

			/* expand tilde to homedir */
			if (url_tildeExpand(local_filename, local_filename_buf,
					    1024) == 0) {
				xfree(local_filename);
				local_filename = (char *)
				  xmalloc(strlen(local_filename_buf)+1);
				strcpy(local_filename, local_filename_buf);
				Debug(20, 1, ("Tilde expanded to %s\n",
					      local_filename));
			}

			/*
			 *  Don't use the mapping if the file is unreadable,
			 *  if fstat() fails, if it's a special file, or if
			 *  it's executable.
			 */
			if (stat(local_filename, &sb) < 0 ||
			    !S_ISREG(sb.st_mode) ||
			    (sb.st_mode & S_IXUSR) ||
			    (fd = open(local_filename, O_RDONLY, 0)) < 0) {
				xfree(local_filename);
				local_filename = NULL;
			}
			if (fd >= 0)
				(void) close(fd);
		}

		/* Special hacks for news: URLs.  We want to change     */
		/* news:comp.sex.html into                              */
		/* /var/spool/nov/comp/sex/html/.overview               */
		/* The local mapping should be:                         */
		/*    news:overview     /var/spool/nov/                 */
		if (!strncasecmp("news:overview", l->from, 13)) {
			if (up->type == URL_NEWS && (strchr(up->url, '@') == 0)) {
				int fd;
				char *group_path;
				local_filename = xmalloc(strlen(l->to) +
				    strlen(up->pathname) + 20);
				group_path = xstrdup(up->pathname);
				for (s = group_path; *s; s++)	/* dots to slashes */
					if (*s == '.')
						*s = '/';
				sprintf(local_filename, "%s%s/.overview",
				    l->to, group_path);
				xfree(group_path);
				if ((fd = open(local_filename, O_RDONLY, 0)) < 0 ||
				    fstat(fd, &sb) < 0 || !S_ISREG(sb.st_mode) ||
				    (sb.st_mode & S_IXUSR)) {
					xfree(local_filename);
					local_filename = NULL;
				}
				if (fd >= 0)
					(void) close(fd);
			}
		}
	}

	if (local_filename != NULL
	    && (s = xstrdup(local_filename))) {
		Debug(20, 1, ("url_open: Local Mapping succeeded: %s -> %s\n",
			up->url, local_filename));
		if (up->type == URL_HTTP)
			up->http_mime_hdr = xstrdup("text/html");
		up->filename = s;	/* point to the symlink */
		up->shsafe_filename = shsafe_path(up->filename);
		up->flags |= URL_FLAG_LOCAL_MAPPED;
		xfree(local_filename);
		local_filename = NULL;
		return (up);
	}
	/* Type-specific additions to the URL */
	Debug(20, 5, ("url_open: type=%d\n", up->type));
	switch (up->type) {
	case URL_FILE:
		up->filename = xstrdup(up->pathname);
		up->shsafe_filename = shsafe_path(up->filename);

		break;
	case URL_FTP:

		/*      If no userinfo yet, see if we can get it from the
		 * **   FTPAuth.cf file (which came from FTP-Auth: in
		 * **   gatherer.cf.                                    */