static CURLcode parseurlandfillconn(struct SessionHandle *data,
                                    struct connectdata *conn,
                                    bool *prot_missing,
                                    char **userp, char **passwdp,
                                    char **optionsp)
{
  char *at;
  char *fragment;
  char *path = data->state.path;
  char *query;
  int rc;
  char protobuf[16] = "";
  const char *protop = "";
  CURLcode result;
  bool rebuild_url = FALSE;

  *prot_missing = FALSE;

  /* We might pass the entire URL into the request so we need to make sure
   * there are no bad characters in there.*/
  if(strpbrk(data->change.url, "\r\n")) {
    failf(data, "Illegal characters found in URL");
    return CURLE_URL_MALFORMAT;
  }

  /*************************************************************
   * Parse the URL.
   *
   * We need to parse the url even when using the proxy, because we will need
   * the hostname and port in case we are trying to SSL connect through the
   * proxy -- and we don't know if we will need to use SSL until we parse the
   * url ...
   ************************************************************/
  if((2 == sscanf(data->change.url, "%15[^:]:%[^\n]",
                  protobuf, path)) &&
     Curl_raw_equal(protobuf, "file")) {
    if(path[0] == '/' && path[1] == '/') {
      /* Allow omitted hostname (e.g. file:/<path>).  This is not strictly
       * speaking a valid file: URL by RFC 1738, but treating file:/<path> as
       * file://localhost/<path> is similar to how other schemes treat missing
       * hostnames.  See RFC 1808. */

      /* This cannot be done with strcpy() in a portable manner, since the
         memory areas overlap! */
      memmove(path, path + 2, strlen(path + 2)+1);
    }
    /*
     * we deal with file://<host>/<path> differently since it supports no
     * hostname other than "localhost" and "127.0.0.1", which is unique among
     * the URL protocols specified in RFC 1738
     */
    if(path[0] != '/') {
      /* the URL included a host name, we ignore host names in file:// URLs
         as the standards don't define what to do with them */
      char *ptr=strchr(path, '/');
      if(ptr) {
        /* there was a slash present

           RFC1738 (section 3.1, page 5) says:

           The rest of the locator consists of data specific to the scheme,
           and is known as the "url-path". It supplies the details of how the
           specified resource can be accessed. Note that the "/" between the
           host (or port) and the url-path is NOT part of the url-path.

           As most agents use file://localhost/foo to get '/foo' although the
           slash preceding foo is a separator and not a slash for the path,
           a URL as file://localhost//foo must be valid as well, to refer to
           the same file with an absolute path.
        */

        if(ptr[1] && ('/' == ptr[1]))
          /* if there was two slashes, we skip the first one as that is then
             used truly as a separator */
          ptr++;

        /* This cannot be made with strcpy, as the memory chunks overlap! */
        memmove(path, ptr, strlen(ptr)+1);
      }
    }

    protop = "file"; /* protocol string */
  }
  else {
    /* clear path */
    path[0]=0;

    if(2 > sscanf(data->change.url,
                   "%15[^\n:]://%[^\n/?]%[^\n]",
                   protobuf,
                   conn->host.name, path)) {

      /*
       * The URL was badly formatted, let's try the browser-style _without_
       * protocol specified like 'http://'.
       */
      rc = sscanf(data->change.url, "%[^\n/?]%[^\n]", conn->host.name, path);
      if(1 > rc) {
        /*
         * We couldn't even get this format.
         * djgpp 2.04 has a sscanf() bug where 'conn->host.name' is
         * assigned, but the return value is EOF!
         */
#if defined(__DJGPP__) && (DJGPP_MINOR == 4)
        if(!(rc == -1 && *conn->host.name))
#endif
        {
          failf(data, "<url> malformed");
          return CURLE_URL_MALFORMAT;
        }
      }

      /*
       * Since there was no protocol part specified, we guess what protocol it
       * is based on the first letters of the server name.
       */

      /* Note: if you add a new protocol, please update the list in
       * lib/version.c too! */

      if(checkprefix("FTP.", conn->host.name))
        protop = "ftp";
      else if(checkprefix("DICT.", conn->host.name))
        protop = "DICT";
      else if(checkprefix("LDAP.", conn->host.name))
        protop = "LDAP";
      else if(checkprefix("IMAP.", conn->host.name))
        protop = "IMAP";
      else if(checkprefix("SMTP.", conn->host.name))
        protop = "smtp";
      else if(checkprefix("POP3.", conn->host.name))
        protop = "pop3";
      else {
        protop = "http";
      }

      *prot_missing = TRUE; /* not given in URL */
    }
    else
      protop = protobuf;
  }

  /* We search for '?' in the host name (but only on the right side of a
   * @-letter to allow ?-letters in username and password) to handle things
   * like http://example.com?param= (notice the missing '/').
   */
  at = strchr(conn->host.name, '@');
  if(at)
    query = strchr(at+1, '?');
  else
    query = strchr(conn->host.name, '?');

  if(query) {
    /* We must insert a slash before the '?'-letter in the URL. If the URL had
       a slash after the '?', that is where the path currently begins and the
       '?string' is still part of the host name.

       We must move the trailing part from the host name and put it first in
       the path. And have it all prefixed with a slash.
    */

    size_t hostlen = strlen(query);
    size_t pathlen = strlen(path);

    /* move the existing path plus the zero byte forward, to make room for
       the host-name part */
    memmove(path+hostlen+1, path, pathlen+1);

     /* now copy the trailing host part in front of the existing path */
    memcpy(path+1, query, hostlen);

    path[0]='/'; /* prepend the missing slash */
    rebuild_url = TRUE;

    *query=0; /* now cut off the hostname at the ? */
  }
  else if(!path[0]) {
    /* if there's no path set, use a single slash */
    strcpy(path, "/");
    rebuild_url = TRUE;
  }

  /* If the URL is malformatted (missing a '/' after hostname before path) we
   * insert a slash here. The only letter except '/' we accept to start a path
   * is '?'.
   */
  if(path[0] == '?') {
    /* We need this function to deal with overlapping memory areas. We know
       that the memory area 'path' points to is 'urllen' bytes big and that
       is bigger than the path. Use +1 to move the zero byte too. */
    memmove(&path[1], path, strlen(path)+1);
    path[0] = '/';
    rebuild_url = TRUE;
  }
  else if(!data->set.path_as_is) {
    /* sanitise paths and remove ../ and ./ sequences according to RFC3986 */
    char *newp = Curl_dedotdotify(path);
    if(!newp)
      return CURLE_OUT_OF_MEMORY;

    if(strcmp(newp, path)) {
      rebuild_url = TRUE;
      free(data->state.pathbuffer);
      data->state.pathbuffer = newp;
      data->state.path = newp;
      path = newp;
    }
    else
      free(newp);
  }

  /*
   * "rebuild_url" means that one or more URL components have been modified so
   * we need to generate an updated full version.  We need the corrected URL
   * when communicating over HTTP proxy and we don't know at this point if
   * we're using a proxy or not.
   */
  if(rebuild_url) {
    char *reurl;

    size_t plen = strlen(path); /* new path, should be 1 byte longer than
                                   the original */
    size_t urllen = strlen(data->change.url); /* original URL length */

    size_t prefixlen = strlen(conn->host.name);

    if(!*prot_missing)
      prefixlen += strlen(protop) + strlen("://");

    reurl = malloc(urllen + 2); /* 2 for zerobyte + slash */
    if(!reurl)
      return CURLE_OUT_OF_MEMORY;

    /* copy the prefix */
    memcpy(reurl, data->change.url, prefixlen);

    /* append the trailing piece + zerobyte */
    memcpy(&reurl[prefixlen], path, plen + 1);

    /* possible free the old one */
    if(data->change.url_alloc) {
      Curl_safefree(data->change.url);
      data->change.url_alloc = FALSE;
    }

    infof(data, "Rebuilt URL to: %s\n", reurl);

    data->change.url = reurl;
    data->change.url_alloc = TRUE; /* free this later */
  }

  /*
   * Parse the login details from the URL and strip them out of
   * the host name
   */
  result = parse_url_login(data, conn, userp, passwdp, optionsp);
  if(result)
    return result;

  if(conn->host.name[0] == '[') {
    /* This looks like an IPv6 address literal.  See if there is an address
       scope if there is no location header */
    char *percent = strchr(conn->host.name, '%');
    if(percent) {
      unsigned int identifier_offset = 3;
      char *endp;
      unsigned long scope;
      if(strncmp("%25", percent, 3) != 0) {
        infof(data,
              "Please URL encode %% as %%25, see RFC 6874.\n");
        identifier_offset = 1;
      }
      scope = strtoul(percent + identifier_offset, &endp, 10);
      if(*endp == ']') {
        /* The address scope was well formed.  Knock it out of the
           hostname. */
        memmove(percent, endp, strlen(endp)+1);
        conn->scope_id = (unsigned int)scope;
      }
      else {
        /* Zone identifier is not numeric */
#if defined(HAVE_NET_IF_H) && defined(IFNAMSIZ) && defined(HAVE_IF_NAMETOINDEX)
        char ifname[IFNAMSIZ + 2];
        char *square_bracket;
        unsigned int scopeidx = 0;
        strncpy(ifname, percent + identifier_offset, IFNAMSIZ + 2);
        /* Ensure nullbyte termination */
        ifname[IFNAMSIZ + 1] = '\0';
        square_bracket = strchr(ifname, ']');
        if(square_bracket) {
          /* Remove ']' */
          *square_bracket = '\0';
          scopeidx = if_nametoindex(ifname);
          if(scopeidx == 0) {
            infof(data, "Invalid network interface: %s; %s\n", ifname,
                  strerror(errno));
          }
        }
        if(scopeidx > 0) {
          char *p = percent + identifier_offset + strlen(ifname);

          /* Remove zone identifier from hostname */
          memmove(percent, p, strlen(p) + 1);
          conn->scope_id = scopeidx;
        }
        else
#endif /* HAVE_NET_IF_H && IFNAMSIZ */
          infof(data, "Invalid IPv6 address format\n");
      }
    }
  }

  if(data->set.scope_id)
    /* Override any scope that was set above.  */
    conn->scope_id = data->set.scope_id;

  /* Remove the fragment part of the path. Per RFC 2396, this is always the
     last part of the URI. We are looking for the first '#' so that we deal
     gracefully with non conformant URI such as http://example.com#foo#bar. */
  fragment = strchr(path, '#');
  if(fragment) {
    *fragment = 0;

    /* we know the path part ended with a fragment, so we know the full URL
       string does too and we need to cut it off from there so it isn't used
       over proxy */
    fragment = strchr(data->change.url, '#');
    if(fragment)
      *fragment = 0;
  }

  /*
   * So if the URL was A://B/C#D,
   *   protop is A
   *   conn->host.name is B
   *   data->state.path is /C
   */

  return findprotocol(data, conn, protop);
}
Unknown