/*********************************************************************
 *
 * File        :  $Source: /cvsroot/ijbswa/current/urlmatch.c,v $
 *
 * Purpose     :  Declares functions to match URLs against URL
 *                patterns.
 *
 * Copyright   :  Written by and Copyright (C) 2001-2025
 *                the Privoxy team. https://www.privoxy.org/
 *
 *                Based on the Internet Junkbuster originally written
 *                by and Copyright (C) 1997 Anonymous Coders and
 *                Junkbusters Corporation.  http://www.junkbusters.com
 *
 *                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.
 *
 *                The GNU General Public License should be included with
 *                this file.  If not, you can view it at
 *                http://www.gnu.org/copyleft/gpl.html
 *                or write to the Free Software Foundation, Inc., 59
 *                Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 *********************************************************************/


#include "config.h"

#ifndef _WIN32
#include <stdio.h>
#include <sys/types.h>
#endif

#include <stdlib.h>
#include <ctype.h>
#include <assert.h>
#include <string.h>

#if !defined(_WIN32)
#include <unistd.h>
#endif

#include "project.h"
#include "urlmatch.h"
#include "ssplit.h"
#include "miscutil.h"
#include "errlog.h"

enum regex_anchoring
{
   NO_ANCHORING,
   LEFT_ANCHORED,
   RIGHT_ANCHORED,
   RIGHT_ANCHORED_HOST
};
static jb_err compile_vanilla_host_pattern(struct pattern_spec *url, const char *host_pattern);
#ifdef FEATURE_PCRE_HOST_PATTERNS
static jb_err compile_pcre_host_pattern(struct pattern_spec *url, const char *host_pattern);
#endif

/*********************************************************************
 *
 * Function    :  free_http_request
 *
 * Description :  Freez a http_request structure
 *
 * Parameters  :
 *          1  :  http = points to a http_request structure to free
 *
 * Returns     :  N/A
 *
 *********************************************************************/
void free_http_request(struct http_request *http)
{
   assert(http);

   freez(http->cmd);
   freez(http->ocmd);
   freez(http->gpc);
   freez(http->host);
   freez(http->url);
   freez(http->hostport);
   freez(http->path);
   freez(http->version);
   freez(http->host_ip_addr_str);
   freez(http->dbuffer);
   freez(http->dvec);
   http->dcount = 0;
}


/*********************************************************************
 *
 * Function    :  init_domain_components
 *
 * Description :  Splits the domain name so we can compare it
 *                against wildcards. It used to be part of
 *                parse_http_url, but was separated because the
 *                same code is required in chat() in case of
 *                intercepted requests.
 *
 * Parameters  :
 *          1  :  http = pointer to the http structure to hold elements.
 *
 * Returns     :  JB_ERR_OK on success
 *                JB_ERR_PARSE on malformed command/URL
 *                             or >100 domains deep.
 *
 *********************************************************************/
jb_err init_domain_components(struct http_request *http)
{
   char *vec[BUFFER_SIZE];
   size_t size;
   char *p;

   assert(http->dbuffer == NULL);
   http->dbuffer = strdup_or_die(http->host);

   /* map to lower case */
   for (p = http->dbuffer; *p ; p++)
   {
      *p = (char)privoxy_tolower(*p);
   }

   /* split the domain name into components */
   http->dcount = ssplit(http->dbuffer, ".", vec, SZ(vec));

   if (http->dcount <= 0)
   {
      /*
       * Error: More than SZ(vec) components in domain
       *    or: no components in domain
       */
      log_error(LOG_LEVEL_ERROR, "More than SZ(vec) components in domain or none at all.");
      return JB_ERR_PARSE;
   }

   /* save a copy of the pointers in dvec */
   size = (size_t)http->dcount * sizeof(*http->dvec);

   assert(http->dvec == NULL);
   http->dvec = malloc_or_die(size);

   memcpy(http->dvec, vec, size);

   return JB_ERR_OK;
}


/*********************************************************************
 *
 * Function    :  url_requires_percent_encoding
 *
 * Description :  Checks if an URL contains invalid characters
 *                according to RFC 3986 that should be percent-encoded.
 *                Does not verify whether or not the passed string
 *                actually is a valid URL.
 *
 * Parameters  :
 *          1  :  url = URL to check
 *
 * Returns     :  True in case of valid URLs, false otherwise
 *
 *********************************************************************/
int url_requires_percent_encoding(const char *url)
{
   static const char allowed_characters[128] = {
      '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
      '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
      '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
      '\0', '\0', '\0', '!',  '\0', '#',  '$',  '%',  '&',  '\'',
      '(',  ')',  '*',  '+',  ',',  '-',  '.',  '/',  '0',  '1',
      '2',  '3',  '4',  '5',  '6',  '7',  '8',  '9',  ':',  ';',
      '\0', '=',  '\0', '?',  '@',  'A',  'B',  'C',  'D',  'E',
      'F',  'G',  'H',  'I',  'J',  'K',  'L',  'M',  'N',  'O',
      'P',  'Q',  'R',  'S',  'T',  'U',  'V',  'W',  'X',  'Y',
      'Z',  '[',  '\0', ']',  '\0', '_',  '\0', 'a',  'b',  'c',
      'd',  'e',  'f',  'g',  'h',  'i',  'j',  'k',  'l',  'm',
      'n',  'o',  'p',  'q',  'r',  's',  't',  'u',  'v',  'w',
      'x',  'y',  'z',  '\0', '\0', '\0', '~',  '\0'
   };

   while (*url != '\0')
   {
      const unsigned int i = (unsigned char)*url++;
      if (i >= sizeof(allowed_characters) || '\0' == allowed_characters[i])
      {
         return TRUE;
      }
   }

   return FALSE;

}


/*********************************************************************
 *
 * Function    :  parse_http_url
 *
 * Description :  Parse out the host and port from the URL.  Find the
 *                hostname & path, port (if ':'), and/or password (if '@')
 *
 * Parameters  :
 *          1  :  url = URL (or is it URI?) to break down
 *          2  :  http = pointer to the http structure to hold elements.
 *                       Must be initialized with valid values (like NULLs).
 *          3  :  require_protocol = Whether or not URLs without
 *                                   protocol are acceptable.
 *
 * Returns     :  JB_ERR_OK on success
 *                JB_ERR_PARSE on malformed command/URL
 *                             or >100 domains deep.
 *
 *********************************************************************/
jb_err parse_http_url(const char *url, struct http_request *http, int require_protocol)
{
   int host_available = 1; /* A proxy can dream. */

   /*
    * Save our initial URL
    */
   http->url = strdup_or_die(url);

   /*
    * Check for * URI. If found, we're done.
    */
   if (*http->url == '*')
   {
      http->path = strdup_or_die("*");
      http->hostport = strdup_or_die("");
      if (http->url[1] != '\0')
      {
         return JB_ERR_PARSE;
      }
      return JB_ERR_OK;
   }


   /*
    * Split URL into protocol, hostport, path.
    */
   {
      char *buf;
      char *url_noproto;
      char *url_path;

      buf = strdup_or_die(url);

      /* Find the start of the URL in our scratch space */
      url_noproto = buf;
      if (strncmpic(url_noproto, "http://",  7) == 0)
      {
         url_noproto += 7;
      }
      else if (strncmpic(url_noproto, "https://", 8) == 0)
      {
         /*
          * Should only happen when called from cgi_show_url_info()
          * or when the request was https-inspected and the request
          * line got rewritten.
          */
         url_noproto += 8;
         http->ssl = 1;
      }
      else if (*url_noproto == '/')
      {
        /*
         * Short request line without protocol and host.
         * Most likely because the client's request
         * was intercepted and redirected into Privoxy.
         */
         http->host = NULL;
         host_available = 0;
      }
      else if (require_protocol)
      {
         freez(buf);
         return JB_ERR_PARSE;
      }

      url_path = strchr(url_noproto, '/');
      if (url_path != NULL)
      {
         /*
          * Got a path.
          *
          * If FEATURE_HTTPS_INSPECTION isn't available, ignore the
          * path for https URLs so that we get consistent behaviour
          * if a https URL is parsed. When the URL is actually
          * retrieved, https hides the path part.
          */
         http->path = strdup_or_die(
#ifndef FEATURE_HTTPS_INSPECTION
            http->ssl ? "/" :
#endif
            url_path
         );
         *url_path = '\0';
         http->hostport = string_tolower(url_noproto);
      }
      else
      {
         /*
          * Repair broken HTTP requests that don't contain a path,
          * or CONNECT requests
          */
         http->path = strdup_or_die("/");
         http->hostport = string_tolower(url_noproto);
      }

      freez(buf);

      if (http->hostport == NULL)
      {
         return JB_ERR_PARSE;
      }
   }

   if (!host_available)
   {
      if (!require_protocol)
      {
         log_error(LOG_LEVEL_ERROR, "No host found in request line.");
         return JB_ERR_PARSE;
      }
      /* Without host, there is nothing left to do here */
      return JB_ERR_OK;
   }

   /*
    * Split hostport into user/password (ignored), host, port.
    */
   {
      char *buf;
      char *host;
      char *port;

      buf = strdup_or_die(http->hostport);

      /* check if url contains username and/or password */
      host = strchr(buf, '@');
      if (host != NULL)
      {
         /* Contains username/password, skip it and the @ sign. */
         host++;
      }
      else
      {
         /* No username or password. */
         host = buf;
      }

      /* Move after hostname before port number */
      if (*host == '[')
      {
         /* Numeric IPv6 address delimited by brackets */
         host++;
         port = strchr(host, ']');

         if (port == NULL)
         {
            /* Missing closing bracket */
            freez(buf);
            return JB_ERR_PARSE;
         }

         *port++ = '\0';

         if (*port == '\0')
         {
            port = NULL;
         }
         else if (*port != ':')
         {
            /* Garbage after closing bracket */
            freez(buf);
            return JB_ERR_PARSE;
         }
      }
      else
      {
         /* Plain non-escaped hostname */
         port = strchr(host, ':');
      }

      /* check if url contains port */
      if (port != NULL)
      {
         /* Contains port */
         char *endptr;
         long parsed_port;
         /* Terminate hostname and point to start of port string */
         *port++ = '\0';
         parsed_port = strtol(port, &endptr, 10);
         if ((parsed_port <= 0) || (parsed_port > 65535) || (*endptr != '\0'))
         {
            log_error(LOG_LEVEL_ERROR, "Invalid port in URL: %s.", url);
            freez(buf);
            return JB_ERR_PARSE;
         }
         http->port = (int)parsed_port;
      }
      else
      {
         /* No port specified. */
         http->port = (http->ssl ? 443 : 80);
      }

      http->host = strdup_or_die(host);

      freez(buf);
   }

   /* Split domain name so we can compare it against wildcards */
   return init_domain_components(http);

}


/*********************************************************************
 *
 * Function    :  unknown_method
 *
 * Description :  Checks whether a method is unknown.
 *
 * Parameters  :
 *          1  :  method = points to a http method
 *
 * Returns     :  TRUE if it's unknown, FALSE otherwise.
 *
 *********************************************************************/
static int unknown_method(const char *method)
{
   static const char * const known_http_methods[] = {
      /* Basic HTTP request type */
      "GET", "HEAD", "POST", "PUT", "DELETE", "OPTIONS", "TRACE", "CONNECT",
      /* webDAV extensions (RFC2518) */
      "PROPFIND", "PROPPATCH", "MOVE", "COPY", "MKCOL", "LOCK", "UNLOCK",
      /*
       * Microsoft webDAV extension for Exchange 2000.  See:
       * http://lists.w3.org/Archives/Public/w3c-dist-auth/2002JanMar/0001.html
       * http://msdn.microsoft.com/library/en-us/wss/wss/_webdav_methods.asp
       */
      "BCOPY", "BMOVE", "BDELETE", "BPROPFIND", "BPROPPATCH",
      /*
       * Another Microsoft webDAV extension for Exchange 2000.  See:
       * http://systems.cs.colorado.edu/grunwald/MobileComputing/Papers/draft-cohen-gena-p-base-00.txt
       * http://lists.w3.org/Archives/Public/w3c-dist-auth/2002JanMar/0001.html
       * http://msdn.microsoft.com/library/en-us/wss/wss/_webdav_methods.asp
       */
      "SUBSCRIBE", "UNSUBSCRIBE", "NOTIFY", "POLL",
      /*
       * Yet another WebDAV extension, this time for
       * Web Distributed Authoring and Versioning (RFC3253)
       */
      "VERSION-CONTROL", "REPORT", "CHECKOUT", "CHECKIN", "UNCHECKOUT",
      "MKWORKSPACE", "UPDATE", "LABEL", "MERGE", "BASELINE-CONTROL", "MKACTIVITY",
      /*
       * The PATCH method is defined by RFC5789, the format of the
       * actual patch in the body depends on the application, but from
       * Privoxy's point of view it doesn't matter.
       */
      "PATCH",
   };
   int i;

   for (i = 0; i < SZ(known_http_methods); i++)
   {
      if (0 == strcmpic(method, known_http_methods[i]))
      {
         return FALSE;
      }
   }

   return TRUE;

}


/*********************************************************************
 *
 * Function    :  normalize_http_version
 *
 * Description :  Take a supported HTTP version string and remove
 *                leading zeroes etc., reject unsupported versions.
 *
 *                This is an explicit RFC 2616 (3.1) MUST and
 *                RFC 7230 mandates that intermediaries send their
 *                own HTTP-version in forwarded messages.
 *
 * Parameters  :
 *          1  :  http_version = HTTP version string
 *
 * Returns     :  JB_ERR_OK on success
 *                JB_ERR_PARSE if the HTTP version is unsupported
 *
 *********************************************************************/
static jb_err normalize_http_version(char *http_version)
{
   unsigned int major_version;
   unsigned int minor_version;

   if (2 != sscanf(http_version, "HTTP/%u.%u", &major_version, &minor_version))
   {
      log_error(LOG_LEVEL_ERROR, "Unsupported HTTP version: %s", http_version);
      return JB_ERR_PARSE;
   }

   if (major_version != 1 || (minor_version != 0 && minor_version != 1))
   {
      log_error(LOG_LEVEL_ERROR, "The only supported HTTP "
         "versions are 1.0 and 1.1. This rules out: %s", http_version);
      return JB_ERR_PARSE;
   }

   assert(strlen(http_version) >= 8);
   snprintf(http_version, 9, "HTTP/%u.%u", major_version, minor_version);

   return JB_ERR_OK;

}


/*********************************************************************
 *
 * Function    :  parse_http_request
 *
 * Description :  Parse out the host and port from the URL.  Find the
 *                hostname & path, port (if ':'), and/or password (if '@')
 *
 * Parameters  :
 *          1  :  req = HTTP request line to break down
 *          2  :  http = pointer to the http structure to hold elements
 *
 * Returns     :  JB_ERR_OK on success
 *                JB_ERR_CGI_PARAMS on malformed command/URL
 *                                  or >100 domains deep.
 *
 *********************************************************************/
jb_err parse_http_request(const char *req, struct http_request *http)
{
   char *buf;
   char *v[3];
   int n;
   jb_err err;

   memset(http, '\0', sizeof(*http));

   buf = strdup_or_die(req);

   n = ssplit(buf, " \r\n", v, SZ(v));
   if (n != 3)
   {
      freez(buf);
      return JB_ERR_PARSE;
   }

   /*
    * Fail in case of unknown methods
    * which we might not handle correctly.
    *
    * XXX: There should be a config option
    * to forward requests with unknown methods
    * anyway. Most of them don't need special
    * steps.
    */
   if (unknown_method(v[0]))
   {
      log_error(LOG_LEVEL_ERROR, "Unknown HTTP method detected: %s", v[0]);
      freez(buf);
      return JB_ERR_PARSE;
   }

   if (JB_ERR_OK != normalize_http_version(v[2]))
   {
      freez(buf);
      return JB_ERR_PARSE;
   }

   http->ssl = !strcmpic(v[0], "CONNECT");

   err = parse_http_url(v[1], http, !http->ssl);
   if (err)
   {
      freez(buf);
      return err;
   }

   /*
    * Copy the details into the structure
    */
   http->cmd = strdup_or_die(req);
   http->gpc = strdup_or_die(v[0]);
   http->version = strdup_or_die(v[2]);
   http->ocmd = strdup_or_die(http->cmd);

   freez(buf);

   return JB_ERR_OK;

}


/*********************************************************************
 *
 * Function    :  compile_pattern
 *
 * Description :  Compiles a host, domain or TAG pattern.
 *
 * Parameters  :
 *          1  :  pattern = The pattern to compile.
 *          2  :  anchoring = How the regex should be modified
 *                            before compilation. Can be either
 *                            one of NO_ANCHORING, LEFT_ANCHORED,
 *                            RIGHT_ANCHORED or RIGHT_ANCHORED_HOST.
 *          3  :  url     = In case of failures, the spec member is
 *                          logged and the structure freed.
 *          4  :  regex   = Where the compiled regex should be stored.
 *
 * Returns     :  JB_ERR_OK - Success
 *                JB_ERR_PARSE - Cannot parse regex
 *
 *********************************************************************/
static jb_err compile_pattern(const char *pattern, enum regex_anchoring anchoring,
                              struct pattern_spec *url, pcre2_code **regex)
{
   PCRE2_UCHAR error_message[120];
   int errcode;
   const char *fmt = NULL;
   char *rebuf;
   size_t rebuf_size;
   PCRE2_SIZE error_offset;
   int ret;

   assert(pattern);

   if (pattern[0] == '\0')
   {
      *regex = NULL;
      return JB_ERR_OK;
   }

   switch (anchoring)
   {
      case NO_ANCHORING:
         fmt = "%s";
         break;
      case RIGHT_ANCHORED:
         fmt = "%s$";
         break;
      case RIGHT_ANCHORED_HOST:
         fmt = "%s\\.?$";
         break;
      case LEFT_ANCHORED:
         fmt = "^%s";
         break;
      default:
         log_error(LOG_LEVEL_FATAL,
            "Invalid anchoring in compile_pattern %d", anchoring);
   }
   rebuf_size = strlen(pattern) + strlen(fmt);
   rebuf = malloc_or_die(rebuf_size);

   snprintf(rebuf, rebuf_size, fmt, pattern);

   *regex = pcre2_compile((const unsigned char *)rebuf,
      PCRE2_ZERO_TERMINATED, PCRE2_CASELESS, &errcode,
      &error_offset, NULL);
   if (*regex == NULL)
   {
      pcre2_get_error_message(errcode, error_message, sizeof(error_message));
      log_error(LOG_LEVEL_ERROR, "Failed to compile '%s' (%s) from '%s': %s",
         pattern, rebuf, url->spec, error_message);
      freez(rebuf);

      return JB_ERR_PARSE;
   }

#ifndef DISABLE_PCRE_JIT_COMPILATION
   /* Try to enable JIT compilation but continue if it's unsupported. */
   if ((ret = pcre2_jit_compile(*regex, PCRE2_JIT_COMPLETE)) &&
       (ret != PCRE2_ERROR_JIT_BADOPTION))
   {
      pcre2_get_error_message(ret, error_message, sizeof(error_message));
      log_error(LOG_LEVEL_ERROR,
         "Failed to JIT-compile '%s' (%s) from '%s': %s",
         pattern, rebuf, url->spec, error_message);
      freez(rebuf);

      return JB_ERR_PARSE;
   }
#endif

   freez(rebuf);

   return JB_ERR_OK;

}


/*********************************************************************
 *
 * Function    :  compile_url_pattern
 *
 * Description :  Compiles the three parts of an URL pattern.
 *
 * Parameters  :
 *          1  :  url = Target pattern_spec to be filled in.
 *          2  :  buf = The url pattern to compile. Will be messed up.
 *
 * Returns     :  JB_ERR_OK - Success
 *                JB_ERR_MEMORY - Out of memory
 *                JB_ERR_PARSE - Cannot parse regex
 *
 *********************************************************************/
static jb_err compile_url_pattern(struct pattern_spec *url, char *buf)
{
   char *p;
   const size_t prefix_length = 18;

#ifdef FEATURE_PCRE_HOST_PATTERNS
   if (strncmpic(buf, "PCRE-HOST-PATTERN:", prefix_length) == 0)
   {
      url->pattern.url_spec.host_regex_type = PCRE_HOST_PATTERN;
      /* Overwrite the "PCRE-HOST-PATTERN:" prefix */
      memmove(buf, buf+prefix_length, strlen(buf+prefix_length)+1);
   }
   else
   {
      url->pattern.url_spec.host_regex_type = VANILLA_HOST_PATTERN;
   }
#else
   if (strncmpic(buf, "PCRE-HOST-PATTERN:", prefix_length) == 0)
   {
      log_error(LOG_LEVEL_ERROR,
         "PCRE-HOST-PATTERN detected while Privoxy has been compiled "
         "without FEATURE_PCRE_HOST_PATTERNS: %s",
         buf);
      /* Overwrite the "PCRE-HOST-PATTERN:" prefix */
      memmove(buf, buf+prefix_length, strlen(buf+prefix_length)+1);
      /*
       * The pattern will probably not work as expected.
       * We don't simply return JB_ERR_PARSE here so the
       * regression tests can be loaded with and without
       * FEATURE_PCRE_HOST_PATTERNS.
       */
   }
#endif

   p = strchr(buf, '/');
   if (NULL != p)
   {
      /*
       * Only compile the regex if it consists of more than
       * a single slash, otherwise it wouldn't affect the result.
       */
      if (p[1] != '\0')
      {
         /*
          * XXX: does it make sense to compile the slash at the beginning?
          */
         jb_err err = compile_pattern(p, LEFT_ANCHORED, url, &url->pattern.url_spec.preg);

         if (JB_ERR_OK != err)
         {
            return err;
         }
      }
      *p = '\0';
   }

   /*
    * IPv6 numeric hostnames can contain colons, thus we need
    * to delimit the hostname before the real port separator.
    * As brackets are already used in the hostname pattern,
    * we use angle brackets ('<', '>') instead.
    */
   if ((buf[0] == '<') && (NULL != (p = strchr(buf + 1, '>'))))
   {
      *p++ = '\0';
      buf++;

      if (*p == '\0')
      {
         /* IPv6 address without port number */
         p = NULL;
      }
      else if (*p != ':')
      {
         /* Garbage after address delimiter */
         return JB_ERR_PARSE;
      }
   }
   else
   {
      p = strchr(buf, ':');
   }

   if (NULL != p)
   {
      *p++ = '\0';
      url->pattern.url_spec.port_list = strdup_or_die(p);
   }
   else
   {
      url->pattern.url_spec.port_list = NULL;
   }

   if (buf[0] != '\0')
   {
#ifdef FEATURE_PCRE_HOST_PATTERNS
      if (url->pattern.url_spec.host_regex_type == PCRE_HOST_PATTERN)
      {
         return compile_pcre_host_pattern(url, buf);
      }
      else
#endif
      {
         return compile_vanilla_host_pattern(url, buf);
      }
   }

   return JB_ERR_OK;

}


#ifdef FEATURE_PCRE_HOST_PATTERNS
/*********************************************************************
 *
 * Function    :  compile_pcre_host_pattern
 *
 * Description :  Parses and compiles a pcre host pattern.
 *
 * Parameters  :
 *          1  :  url = Target pattern_spec to be filled in.
 *          2  :  host_pattern = Host pattern to compile.
 *
 * Returns     :  JB_ERR_OK - Success
 *                JB_ERR_MEMORY - Out of memory
 *                JB_ERR_PARSE - Cannot parse regex
 *
 *********************************************************************/
static jb_err compile_pcre_host_pattern(struct pattern_spec *url, const char *host_pattern)
{
   return compile_pattern(host_pattern, RIGHT_ANCHORED_HOST, url, &url->pattern.url_spec.host_regex);
}
#endif /* def FEATURE_PCRE_HOST_PATTERNS */


/*********************************************************************
 *
 * Function    :  compile_vanilla_host_pattern
 *
 * Description :  Parses and "compiles" an old-school host pattern.
 *
 * Parameters  :
 *          1  :  url = Target pattern_spec to be filled in.
 *          2  :  host_pattern = Host pattern to parse.
 *
 * Returns     :  JB_ERR_OK - Success
 *                JB_ERR_PARSE - Cannot parse regex
 *
 *********************************************************************/
static jb_err compile_vanilla_host_pattern(struct pattern_spec *url, const char *host_pattern)
{
   char *v[150];
   size_t size;
   char *p;

   /*
    * Parse domain part
    */
   if (host_pattern[strlen(host_pattern) - 1] == '.')
   {
      url->pattern.url_spec.unanchored |= ANCHOR_RIGHT;
   }
   if (host_pattern[0] == '.')
   {
      url->pattern.url_spec.unanchored |= ANCHOR_LEFT;
   }

   /*
    * Split domain into components
    */
   url->pattern.url_spec.dbuffer = strdup_or_die(host_pattern);

   /*
    * Map to lower case
    */
   for (p = url->pattern.url_spec.dbuffer; *p ; p++)
   {
      *p = (char)privoxy_tolower(*p);
   }

   /*
    * Split the domain name into components
    */
   url->pattern.url_spec.dcount = ssplit(url->pattern.url_spec.dbuffer, ".", v, SZ(v));

   if (url->pattern.url_spec.dcount < 0)
   {
      free_pattern_spec(url);
      return JB_ERR_PARSE;
   }
   else if (url->pattern.url_spec.dcount != 0)
   {
      /*
       * Save a copy of the pointers in dvec
       */
      size = (size_t)url->pattern.url_spec.dcount * sizeof(*url->pattern.url_spec.dvec);

      url->pattern.url_spec.dvec = malloc_or_die(size);

      memcpy(url->pattern.url_spec.dvec, v, size);
   }
   /*
    * else dcount == 0 in which case we needn't do anything,
    * since dvec will never be accessed and the pattern will
    * match all domains.
    */
   return JB_ERR_OK;
}


/*********************************************************************
 *
 * Function    :  simplematch
 *
 * Description :  String matching, with a (greedy) '*' wildcard that
 *                stands for zero or more arbitrary characters and
 *                character classes in [], which take both enumerations
 *                and ranges.
 *
 * Parameters  :
 *          1  :  pattern = pattern for matching
 *          2  :  text    = text to be matched
 *
 * Returns     :  0 if match, else nonzero
 *
 *********************************************************************/
static int simplematch(const char *pattern, const char *text)
{
   const unsigned char *pat = (const unsigned char *)pattern;
   const unsigned char *txt = (const unsigned char *)text;
   const unsigned char *fallback = pat;
   int wildcard = 0;

   unsigned char lastchar = 'a';
   unsigned i;
   unsigned char charmap[32];

   while (*txt)
   {

      /* EOF pattern but !EOF text? */
      if (*pat == '\0')
      {
         if (wildcard)
         {
            pat = fallback;
         }
         else
         {
            return 1;
         }
      }

      /* '*' in the pattern?  */
      if (*pat == '*')
      {

         /* The pattern ends afterwards? Speed up the return. */
         if (*++pat == '\0')
         {
            return 0;
         }

         /* Else, set wildcard mode and remember position after '*' */
         wildcard = 1;
         fallback = pat;
      }

      /* Character range specification? */
      if (*pat == '[')
      {
         memset(charmap, '\0', sizeof(charmap));

         while (*++pat != ']')
         {
            if (!*pat)
            {
               return 1;
            }
            else if (*pat == '-')
            {
               if ((*++pat == ']') || *pat == '\0')
               {
                  return(1);
               }
               for (i = lastchar; i <= *pat; i++)
               {
                  charmap[i / 8] |= (unsigned char)(1 << (i % 8));
               }
            }
            else
            {
               charmap[*pat / 8] |= (unsigned char)(1 << (*pat % 8));
               lastchar = *pat;
            }
         }
      } /* -END- if Character range specification */


      /*
       * Char match, or char range match?
       */
      if ((*pat == *txt)
       || (*pat == '?')
       || ((*pat == ']') && (charmap[*txt / 8] & (1 << (*txt % 8)))))
      {
         /*
          * Success: Go ahead
          */
         pat++;
      }
      else if (!wildcard)
      {
         /*
          * No match && no wildcard: No luck
          */
         return 1;
      }
      else if (pat != fallback)
      {
         /*
          * Increment text pointer if in char range matching
          */
         if (*pat == ']')
         {
            txt++;
         }
         /*
          * Wildcard mode && nonmatch beyond fallback: Rewind pattern
          */
         pat = fallback;
         /*
          * Restart matching from current text pointer
          */
         continue;
      }
      txt++;
   }

   /* Cut off extra '*'s */
   if (*pat == '*') pat++;

   /* If this is the pattern's end, fine! */
   return(*pat);

}


/*********************************************************************
 *
 * Function    :  pcre2_pattern_matches
 *
 * Description :  Checks if a compiled pcre2 pattern matches a string.
 *
 * Parameters  :
 *          1  :  pattern = The compiled pattern
 *          2  :  string = The string to check
 *
 * Returns     :  TRUE for yes, FALSE otherwise.
 *
 *********************************************************************/
static int pcre2_pattern_matches(const pcre2_code *pattern, const char *string)
{
   PCRE2_SIZE offset;
   int ret;
   pcre2_match_data *pcre2_matches;

   assert(pattern != NULL);
   assert(string != NULL);

   offset = 0;

   pcre2_matches = pcre2_match_data_create_from_pattern(pattern, NULL);
   if (NULL == pcre2_matches)
   {
      log_error(LOG_LEVEL_ERROR,
         "Out of memory while matching pattern against %s", string);
      return FALSE;
   }

   ret = pcre2_match(pattern, (const unsigned char *)string, strlen(string),
      offset, 0, pcre2_matches, NULL);

   pcre2_match_data_free(pcre2_matches);

   return (ret >= 0);
}


/*********************************************************************
 *
 * Function    :  regex_matches
 *
 * Description :  Checks if a compiled regex pattern matches a string.
 *
 * Parameters  :
 *          1  :  pattern = The compiled pattern
 *          2  :  string = The string to check
 *
 * Returns     :  TRUE for yes, FALSE otherwise.
 *
 *********************************************************************/
int regex_matches(const pcre2_code *pattern, const char *string)
{
   return pcre2_pattern_matches(pattern, string);
}

/*********************************************************************
 *
 * Function    :  simple_domaincmp
 *
 * Description :  Domain-wise Compare fqdn's.  The comparison is
 *                both left- and right-anchored.  The individual
 *                domain names are compared with simplematch().
 *                This is only used by domain_match.
 *
 * Parameters  :
 *          1  :  pv = array of patterns to compare
 *          2  :  fv = array of domain components to compare
 *          3  :  len = length of the arrays (both arrays are the
 *                      same length - if they weren't, it couldn't
 *                      possibly be a match).
 *
 * Returns     :  0 => domains are equivalent, else no match.
 *
 *********************************************************************/
static int simple_domaincmp(char **pv, char **fv, int len)
{
   int n;

   for (n = 0; n < len; n++)
   {
      if (simplematch(pv[n], fv[n]))
      {
         return 1;
      }
   }

   return 0;

}


/*********************************************************************
 *
 * Function    :  domain_match
 *
 * Description :  Domain-wise Compare fqdn's. Governed by the bimap in
 *                p.pattern->unachored, the comparison is un-, left-,
 *                right-anchored, or both.
 *                The individual domain names are compared with
 *                simplematch().
 *
 * Parameters  :
 *          1  :  p = a domain that may contain a '*' as a wildcard.
 *          2  :  fqdn = domain name against which the patterns are compared.
 *
 * Returns     :  0 => domains are equivalent, else no match.
 *
 *********************************************************************/
static int domain_match(const struct pattern_spec *p, const struct http_request *fqdn)
{
   char **pv, **fv;  /* vectors  */
   int    plen, flen;
   int unanchored = p->pattern.url_spec.unanchored & (ANCHOR_RIGHT | ANCHOR_LEFT);

   plen = p->pattern.url_spec.dcount;
   flen = fqdn->dcount;

   if (flen < plen)
   {
      /* fqdn is too short to match this pattern */
      return 1;
   }

   pv   = p->pattern.url_spec.dvec;
   fv   = fqdn->dvec;

   if (unanchored == ANCHOR_LEFT)
   {
      /*
       * Right anchored.
       *
       * Convert this into a fully anchored pattern with
       * the fqdn and pattern the same length
       */
      fv += (flen - plen); /* flen - plen >= 0 due to check above */
      return simple_domaincmp(pv, fv, plen);
   }
   else if (unanchored == 0)
   {
      /* Fully anchored, check length */
      if (flen != plen)
      {
         return 1;
      }
      return simple_domaincmp(pv, fv, plen);
   }
   else if (unanchored == ANCHOR_RIGHT)
   {
      /* Left anchored, ignore all extra in fqdn */
      return simple_domaincmp(pv, fv, plen);
   }
   else
   {
      /* Unanchored */
      int n;
      int maxn = flen - plen;
      for (n = 0; n <= maxn; n++)
      {
         if (!simple_domaincmp(pv, fv, plen))
         {
            return 0;
         }
         /*
          * Doesn't match from start of fqdn
          * Try skipping first part of fqdn
          */
         fv++;
      }
      return 1;
   }

}


/*********************************************************************
 *
 * Function    :  create_pattern_spec
 *
 * Description :  Creates a "pattern_spec" structure from a string.
 *                When finished, free with free_pattern_spec().
 *
 * Parameters  :
 *          1  :  pattern = Target pattern_spec to be filled in.
 *                          Will be zeroed before use.
 *          2  :  buf = Source pattern, null terminated.  NOTE: The
 *                      contents of this buffer are destroyed by this
 *                      function.  If this function succeeds, the
 *                      buffer is copied to pattern->spec.  If this
 *                      function fails, the contents of the buffer
 *                      are lost forever.
 *
 * Returns     :  JB_ERR_OK - Success
 *                JB_ERR_PARSE - Cannot parse regex (Detailed message
 *                               written to system log)
 *
 *********************************************************************/
jb_err create_pattern_spec(struct pattern_spec *pattern, char *buf)
{
   static const struct
   {
      /** The tag pattern prefix to match */
      const char *prefix;

      /** The length of the prefix to match */
      const size_t prefix_length;

      /** The pattern flag */
      const unsigned flag;
   } tag_pattern[] = {
      { "TAG:",              4, PATTERN_SPEC_TAG_PATTERN},
#ifdef FEATURE_CLIENT_TAGS
      { "CLIENT-TAG:",      11, PATTERN_SPEC_CLIENT_TAG_PATTERN},
#endif
      { "NO-REQUEST-TAG:",  15, PATTERN_SPEC_NO_REQUEST_TAG_PATTERN},
      { "NO-RESPONSE-TAG:", 16, PATTERN_SPEC_NO_RESPONSE_TAG_PATTERN}
   };
   int i;

   assert(pattern);
   assert(buf);

   memset(pattern, '\0', sizeof(*pattern));

   /* Remember the original specification for the CGI pages. */
   pattern->spec = strdup_or_die(buf);

   /* Check if it's a tag pattern */
   for (i = 0; i < SZ(tag_pattern); i++)
   {
      if (0 == strncmpic(pattern->spec, tag_pattern[i].prefix, tag_pattern[i].prefix_length))
      {
         /* The regex starts after the prefix */
         const char *tag_regex = buf + tag_pattern[i].prefix_length;

         pattern->flags |= tag_pattern[i].flag;

         return compile_pattern(tag_regex, NO_ANCHORING, pattern,
            &pattern->pattern.tag_regex);
      }
   }

   /* If it isn't a tag pattern it must be an URL pattern. */
   pattern->flags |= PATTERN_SPEC_URL_PATTERN;

   return compile_url_pattern(pattern, buf);

}


/*********************************************************************
 *
 * Function    :  free_pattern_spec
 *
 * Description :  Called from the "unloaders".  Freez the pattern
 *                structure elements.
 *
 * Parameters  :
 *          1  :  pattern = pointer to a pattern_spec structure.
 *
 * Returns     :  N/A
 *
 *********************************************************************/
void free_pattern_spec(struct pattern_spec *pattern)
{
   if (pattern == NULL) return;

   freez(pattern->spec);

   if (!(pattern->flags & PATTERN_SPEC_URL_PATTERN))
   {
      if (pattern->pattern.tag_regex)
      {
         pcre2_code_free(pattern->pattern.tag_regex);
      }
      return;
   }

#ifdef FEATURE_PCRE_HOST_PATTERNS
   if (pattern->pattern.url_spec.host_regex)
   {
      pcre2_code_free(pattern->pattern.url_spec.host_regex);
   }
#endif /* def FEATURE_PCRE_HOST_PATTERNS */
   freez(pattern->pattern.url_spec.dbuffer);
   freez(pattern->pattern.url_spec.dvec);
   pattern->pattern.url_spec.dcount = 0;
   freez(pattern->pattern.url_spec.port_list);
   if (pattern->pattern.url_spec.preg)
   {
      pcre2_code_free(pattern->pattern.url_spec.preg);
   }
}


/*********************************************************************
 *
 * Function    :  port_matches
 *
 * Description :  Compares a port against a port list.
 *
 * Parameters  :
 *          1  :  port      = The port to check.
 *          2  :  port_list = The list of port to compare with.
 *
 * Returns     :  TRUE for yes, FALSE otherwise.
 *
 *********************************************************************/
static int port_matches(const int port, const char *port_list)
{
   return ((NULL == port_list) || match_portlist(port_list, port));
}


/*********************************************************************
 *
 * Function    :  host_matches
 *
 * Description :  Compares a host against a host pattern.
 *
 * Parameters  :
 *          1  :  url = The URL to match
 *          2  :  pattern = The URL pattern
 *
 * Returns     :  TRUE for yes, FALSE otherwise.
 *
 *********************************************************************/
static int host_matches(const struct http_request *http,
                        const struct pattern_spec *pattern)
{
   assert(http->host != NULL);
#ifdef FEATURE_PCRE_HOST_PATTERNS
   if (pattern->pattern.url_spec.host_regex_type == PCRE_HOST_PATTERN)
   {
      return ((NULL == pattern->pattern.url_spec.host_regex)
         || regex_matches(pattern->pattern.url_spec.host_regex, http->host));
   }
#endif
   return ((NULL == pattern->pattern.url_spec.dbuffer) || (0 == domain_match(pattern, http)));
}


/*********************************************************************
 *
 * Function    :  path_matches
 *
 * Description :  Compares a path against a path pattern.
 *
 * Parameters  :
 *          1  :  path = The path to match
 *          2  :  pattern = The URL pattern
 *
 * Returns     :  TRUE for yes, FALSE otherwise.
 *
 *********************************************************************/
static int path_matches(const char *path, const struct pattern_spec *pattern)
{
   return ((NULL == pattern->pattern.url_spec.preg)
      || regex_matches(pattern->pattern.url_spec.preg, path));
}


/*********************************************************************
 *
 * Function    :  url_match
 *
 * Description :  Compare a URL against a URL pattern.
 *
 * Parameters  :
 *          1  :  pattern = a URL pattern
 *          2  :  url = URL to match
 *
 * Returns     :  Nonzero if the URL matches the pattern, else 0.
 *
 *********************************************************************/
int url_match(const struct pattern_spec *pattern,
              const struct http_request *http)
{
   if (!(pattern->flags & PATTERN_SPEC_URL_PATTERN))
   {
      /* It's not an URL pattern and thus shouldn't be matched against URLs */
      return 0;
   }

   return (port_matches(http->port, pattern->pattern.url_spec.port_list)
      && host_matches(http, pattern) && path_matches(http->path, pattern));

}


/*********************************************************************
 *
 * Function    :  match_portlist
 *
 * Description :  Check if a given number is covered by a comma
 *                separated list of numbers and ranges (a,b-c,d,..)
 *
 * Parameters  :
 *          1  :  portlist = String with list
 *          2  :  port = port to check
 *
 * Returns     :  0 => no match
 *                1 => match
 *
 *********************************************************************/
int match_portlist(const char *portlist, int port)
{
   char *min, *max, *next, *portlist_copy;

   min = portlist_copy = strdup_or_die(portlist);

   /*
    * Zero-terminate first item and remember offset for next
    */
   if (NULL != (next = strchr(portlist_copy, (int) ',')))
   {
      *next++ = '\0';
   }

   /*
    * Loop through all items, checking for match
    */
   while (NULL != min)
   {
      if (NULL == (max = strchr(min, (int) '-')))
      {
         /*
          * No dash, check for equality
          */
         if (port == atoi(min))
         {
            freez(portlist_copy);
            return(1);
         }
      }
      else
      {
         /*
          * This is a range, so check if between min and max,
          * or, if max was omitted, between min and 65K
          */
         *max++ = '\0';
         if (port >= atoi(min) && port <= (atoi(max) ? atoi(max) : 65535))
         {
            freez(portlist_copy);
            return(1);
         }

      }

      /*
       * Jump to next item
       */
      min = next;

      /*
       * Zero-terminate next item and remember offset for n+1
       */
      if ((NULL != next) && (NULL != (next = strchr(next, (int) ','))))
      {
         *next++ = '\0';
      }
   }

   freez(portlist_copy);
   return 0;

}


/*********************************************************************
 *
 * Function    :  parse_forwarder_address
 *
 * Description :  Parse out the username, password, host and port from
 *                a forwarder address.
 *
 * Parameters  :
 *          1  :  address = The forwarder address to parse.
 *          2  :  hostname = Used to return the hostname. NULL on error.
 *          3  :  port = Used to return the port. Untouched if no port
 *                       is specified.
 *          4  :  username = Used to return the username if any.
 *          5  :  password = Used to return the password if any.
 *
 * Returns     :  JB_ERR_OK on success
 *                JB_ERR_MEMORY on out of memory
 *                JB_ERR_PARSE on malformed address.
 *
 *********************************************************************/
jb_err parse_forwarder_address(char *address, char **hostname, int *port,
                               char **username, char **password)
{
   char *p;
   char *tmp;

   tmp = *hostname = strdup_or_die(address);

   /* Parse username and password */
   if (username && password && (NULL != (p = strchr(*hostname, '@'))))
   {
      *p++ = '\0';
      *username = strdup_or_die(*hostname);
      *hostname = strdup_or_die(p);

      if (NULL != (p = strchr(*username, ':')))
      {
         *p++ = '\0';
         *password = strdup_or_die(p);
      }
      freez(tmp);
   }

   /* Parse hostname and port */
   p = *hostname;
   if ((*p == '[') && (NULL == strchr(p, ']')))
   {
      /* XXX: Should do some more validity checks here. */
      return JB_ERR_PARSE;
   }

   if ((**hostname == '[') && (NULL != (p = strchr(*hostname, ']'))))
   {
      *p++ = '\0';
      memmove(*hostname, (*hostname + 1), (size_t)(p - *hostname));
      if (*p == ':')
      {
         *port = (int)strtol(++p, NULL, 0);
      }
   }
   else if (NULL != (p = strchr(*hostname, ':')))
   {
      *p++ = '\0';
      *port = (int)strtol(p, NULL, 0);
   }

   return JB_ERR_OK;

}


/*
  Local Variables:
  tab-width: 3
  end:
*/
