path: root/plugins/check_curl.c

/*****************************************************************************
*
* Monitoring check_curl plugin
*
* License: GPL
* Copyright (c) 1999-2019 Monitoring Plugins Development Team
*
* Description:
*
* This file contains the check_curl plugin
*
* This plugin tests the HTTP service on the specified host. It can test
* normal (http) and secure (https) servers, follow redirects, search for
* strings and regular expressions, check connection times, and report on
* certificate expiration times.
*
* This plugin uses functions from the curl library, see
* http://curl.haxx.se
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*
*
*****************************************************************************/
const char *progname = "check_curl";

const char *copyright = "2006-2019";
const char *email = "devel@monitoring-plugins.org";

#include <ctype.h>

#include "common.h"
#include "utils.h"

#ifndef LIBCURL_PROTOCOL_HTTP
#error libcurl compiled without HTTP support, compiling check_curl plugin does not makes a lot of sense
#endif

#include "curl/curl.h"
#include "curl/easy.h"

#include "picohttpparser.h"

#include "uriparser/Uri.h"

#include <arpa/inet.h>

#if defined(HAVE_SSL) && defined(USE_OPENSSL)
#include <openssl/opensslv.h>
#endif

#include <netdb.h>

#define MAKE_LIBCURL_VERSION(major, minor, patch) ((major)*0x10000 + (minor)*0x100 + (patch))

#define DEFAULT_BUFFER_SIZE 2048
#define DEFAULT_SERVER_URL "/"
#define HTTP_EXPECT "HTTP/"
#define INET_ADDR_MAX_SIZE INET6_ADDRSTRLEN
enum {
  MAX_IPV4_HOSTLENGTH = 255,
  HTTP_PORT = 80,
  HTTPS_PORT = 443,
  MAX_PORT = 65535,
  DEFAULT_MAX_REDIRS = 15
};

enum {
  STICKY_NONE = 0,
  STICKY_HOST = 1,
  STICKY_PORT = 2
};

enum {
  FOLLOW_HTTP_CURL = 0,
  FOLLOW_LIBCURL = 1
};

/* for buffers for header and body */
typedef struct {
  char *buf;
  size_t buflen;
  size_t bufsize;
} curlhelp_write_curlbuf;

/* for buffering the data sent in PUT */
typedef struct {
  char *buf;
  size_t buflen;
  off_t pos;
} curlhelp_read_curlbuf;

/* for parsing the HTTP status line */
typedef struct {
  int http_major;   /* major version of the protocol, always 1 (HTTP/0.9
                     * never reached the big internet most likely) */
  int http_minor;   /* minor version of the protocol, usually 0 or 1 */
  int http_code;    /* HTTP return code as in RFC 2145 */
  int http_subcode; /* Microsoft IIS extension, HTTP subcodes, see
                     * http://support.microsoft.com/kb/318380/en-us */
  const char *msg;  /* the human readable message */
  char *first_line; /* a copy of the first line */
} curlhelp_statusline;

/* to know the underlying SSL library used by libcurl */
typedef enum curlhelp_ssl_library {
  CURLHELP_SSL_LIBRARY_UNKNOWN,
  CURLHELP_SSL_LIBRARY_OPENSSL,
  CURLHELP_SSL_LIBRARY_LIBRESSL,
  CURLHELP_SSL_LIBRARY_GNUTLS,
  CURLHELP_SSL_LIBRARY_NSS
} curlhelp_ssl_library;

enum {
  REGS = 2,
  MAX_RE_SIZE = 1024
};
#include "regex.h"
regex_t preg;
regmatch_t pmatch[REGS];
char regexp[MAX_RE_SIZE];
int cflags = REG_NOSUB | REG_EXTENDED | REG_NEWLINE;
int errcode;
int invert_regex = 0;

char *server_address = NULL;
char *host_name = NULL;
char *server_url = 0;
char server_ip[DEFAULT_BUFFER_SIZE];
struct curl_slist *server_ips = NULL;
int specify_port = FALSE;
unsigned short server_port = HTTP_PORT;
unsigned short virtual_port = 0;
int host_name_length;
char output_header_search[30] = "";
char output_string_search[30] = "";
char *warning_thresholds = NULL;
char *critical_thresholds = NULL;
int days_till_exp_warn, days_till_exp_crit;
thresholds *thlds;
char user_agent[DEFAULT_BUFFER_SIZE];
int verbose = 0;
int show_extended_perfdata = FALSE;
int show_body = FALSE;
int min_page_len = 0;
int max_page_len = 0;
int redir_depth = 0;
int max_depth = DEFAULT_MAX_REDIRS;
char *http_method = NULL;
char *http_post_data = NULL;
char *http_content_type = NULL;
CURL *curl;
struct curl_slist *header_list = NULL;
curlhelp_write_curlbuf body_buf;
curlhelp_write_curlbuf header_buf;
curlhelp_statusline status_line;
curlhelp_read_curlbuf put_buf;
char http_header[DEFAULT_BUFFER_SIZE];
long code;
long socket_timeout = DEFAULT_SOCKET_TIMEOUT;
double total_time;
double time_connect;
double time_appconnect;
double time_headers;
double time_firstbyte;
char errbuf[CURL_ERROR_SIZE+1];
CURLcode res;
char url[DEFAULT_BUFFER_SIZE];
char msg[DEFAULT_BUFFER_SIZE];
char perfstring[DEFAULT_BUFFER_SIZE];
char header_expect[MAX_INPUT_BUFFER] = "";
char string_expect[MAX_INPUT_BUFFER] = "";
char server_expect[MAX_INPUT_BUFFER] = HTTP_EXPECT;
int server_expect_yn = 0;
char user_auth[MAX_INPUT_BUFFER] = "";
char proxy_auth[MAX_INPUT_BUFFER] = "";
char **http_opt_headers;
int http_opt_headers_count = 0;
int display_html = FALSE;
int onredirect = STATE_OK;
int followmethod = FOLLOW_HTTP_CURL;
int followsticky = STICKY_NONE;
int use_ssl = FALSE;
int use_sni = TRUE;
int check_cert = FALSE;
typedef union {
  struct curl_slist* to_info;
  struct curl_certinfo* to_certinfo;
} cert_ptr_union;
cert_ptr_union cert_ptr;
int ssl_version = CURL_SSLVERSION_DEFAULT;
char *client_cert = NULL;
char *client_privkey = NULL;
char *ca_cert = NULL;
int verify_peer_and_host = FALSE;
int is_openssl_callback = FALSE;
#if defined(HAVE_SSL) && defined(USE_OPENSSL)
X509 *cert = NULL;
#endif /* defined(HAVE_SSL) && defined(USE_OPENSSL) */
int no_body = FALSE;
int maximum_age = -1;
int address_family = AF_UNSPEC;
curlhelp_ssl_library ssl_library = CURLHELP_SSL_LIBRARY_UNKNOWN;
int curl_http_version = CURL_HTTP_VERSION_NONE;
int automatic_decompression = FALSE;

int process_arguments (int, char**);
void handle_curl_option_return_code (CURLcode res, const char* option);
int check_http (void);
void redir (curlhelp_write_curlbuf*);
char *perfd_time (double microsec);
char *perfd_time_connect (double microsec);
char *perfd_time_ssl (double microsec);
char *perfd_time_firstbyte (double microsec);
char *perfd_time_headers (double microsec);
char *perfd_time_transfer (double microsec);
char *perfd_size (int page_len);
void print_help (void);
void print_usage (void);
void print_curl_version (void);
int curlhelp_initwritebuffer (curlhelp_write_curlbuf*);
int curlhelp_buffer_write_callback (void*, size_t , size_t , void*);
void curlhelp_freewritebuffer (curlhelp_write_curlbuf*);
int curlhelp_initreadbuffer (curlhelp_read_curlbuf *, const char *, size_t);
int curlhelp_buffer_read_callback (void *, size_t , size_t , void *);
void curlhelp_freereadbuffer (curlhelp_read_curlbuf *);
curlhelp_ssl_library curlhelp_get_ssl_library (CURL*);
const char* curlhelp_get_ssl_library_string (curlhelp_ssl_library);
int net_noopenssl_check_certificate (cert_ptr_union*, int, int);

int curlhelp_parse_statusline (const char*, curlhelp_statusline *);
void curlhelp_free_statusline (curlhelp_statusline *);
char *get_header_value (const struct phr_header* headers, const size_t nof_headers, const char* header);
int check_document_dates (const curlhelp_write_curlbuf *, char (*msg)[DEFAULT_BUFFER_SIZE]);
int get_content_length (const curlhelp_write_curlbuf* header_buf, const curlhelp_write_curlbuf* body_buf);

#if defined(HAVE_SSL) && defined(USE_OPENSSL)
int np_net_ssl_check_certificate(X509 *certificate, int days_till_exp_warn, int days_till_exp_crit);
#endif /* defined(HAVE_SSL) && defined(USE_OPENSSL) */

void remove_newlines (char *);
void test_file (char *);

int
main (int argc, char **argv)
{
  int result = STATE_UNKNOWN;

  setlocale (LC_ALL, "");
  bindtextdomain (PACKAGE, LOCALEDIR);
  textdomain (PACKAGE);

  /* Parse extra opts if any */
  argv = np_extra_opts (&argc, argv, progname);

  /* set defaults */
  snprintf( user_agent, DEFAULT_BUFFER_SIZE, "%s/v%s (monitoring-plugins %s, %s)",
    progname, NP_VERSION, VERSION, curl_version());

  /* parse arguments */
  if (process_arguments (argc, argv) == ERROR)
    usage4 (_("Could not parse arguments"));

  if (display_html == TRUE)
    printf ("<A HREF=\"%s://%s:%d%s\" target=\"_blank\">",
      use_ssl ? "https" : "http",
      host_name ? host_name : server_address,
      virtual_port ? virtual_port : server_port,
      server_url);

  result = check_http ();
  return result;
}

#ifdef HAVE_SSL
#ifdef USE_OPENSSL

int verify_callback(int preverify_ok, X509_STORE_CTX *x509_ctx)
{
  /* TODO: we get all certificates of the chain, so which ones
   * should we test?
   * TODO: is the last certificate always the server certificate?
   */
  cert = X509_STORE_CTX_get_current_cert(x509_ctx);
#if OPENSSL_VERSION_NUMBER >= 0x10100000L
  X509_up_ref(cert);
#endif
  if (verbose>=2) {
    puts("* SSL verify callback with certificate:");
    X509_NAME *subject, *issuer;
    printf("*   issuer:\n");
    issuer = X509_get_issuer_name( cert );
    X509_NAME_print_ex_fp(stdout, issuer, 5, XN_FLAG_MULTILINE);
    printf("* curl verify_callback:\n*   subject:\n");
    subject = X509_get_subject_name( cert );
    X509_NAME_print_ex_fp(stdout, subject, 5, XN_FLAG_MULTILINE);
    puts("");
  }
  return 1;
}

CURLcode sslctxfun(CURL *curl, SSL_CTX *sslctx, void *parm)
{
  SSL_CTX_set_verify(sslctx, SSL_VERIFY_PEER, verify_callback);

  return CURLE_OK;
}

#endif /* USE_OPENSSL */
#endif /* HAVE_SSL */

/* returns a string "HTTP/1.x" or "HTTP/2" */
static char *string_statuscode (int major, int minor)
{
  static char buf[10];

  switch (major) {
    case 1:
      snprintf (buf, sizeof (buf), "HTTP/%d.%d", major, minor);
      break;
    case 2:
    case 3:
      snprintf (buf, sizeof (buf), "HTTP/%d", major);
      break;
    default:
      /* assuming here HTTP/N with N>=4 */
      snprintf (buf, sizeof (buf), "HTTP/%d", major);
      break;
  }

  return buf;
}

/* Checks if the server 'reply' is one of the expected 'statuscodes' */
static int
expected_statuscode (const char *reply, const char *statuscodes)
{
  char *expected, *code;
  int result = 0;

  if ((expected = strdup (statuscodes)) == NULL)
    die (STATE_UNKNOWN, _("HTTP UNKNOWN - Memory allocation error\n"));

  for (code = strtok (expected, ","); code != NULL; code = strtok (NULL, ","))
    if (strstr (reply, code) != NULL) {
      result = 1;
      break;
    }

  free (expected);
  return result;
}

void
handle_curl_option_return_code (CURLcode res, const char* option)
{
  if (res != CURLE_OK) {
    snprintf (msg, DEFAULT_BUFFER_SIZE, _("Error while setting cURL option '%s': cURL returned %d - %s"),
      option, res, curl_easy_strerror(res));
    die (STATE_CRITICAL, "HTTP CRITICAL - %s\n", msg);
  }
}

int
lookup_host (const char *host, char *buf, size_t buflen)
{
  struct addrinfo hints, *res, *result;
  int errcode;
  void *ptr;

  memset (&hints, 0, sizeof (hints));
  hints.ai_family = address_family;
  hints.ai_socktype = SOCK_STREAM;
  hints.ai_flags |= AI_CANONNAME;

  errcode = getaddrinfo (host, NULL, &hints, &result);
  if (errcode != 0)
    return errcode;
  
  res = result;

  while (res) {
  inet_ntop (res->ai_family, res->ai_addr->sa_data, buf, buflen);
  switch (res->ai_family) {
    case AF_INET:
      ptr = &((struct sockaddr_in *) res->ai_addr)->sin_addr;
      break;
    case AF_INET6:
      ptr = &((struct sockaddr_in6 *) res->ai_addr)->sin6_addr;
    break;
    }
    inet_ntop (res->ai_family, ptr, buf, buflen);
    if (verbose >= 1)
      printf ("* getaddrinfo IPv%d address: %s\n",
        res->ai_family == PF_INET6 ? 6 : 4, buf);
    res = res->ai_next;
  }
  
  freeaddrinfo(result);

  return 0;
}

int
check_http (void)
{
  int result = STATE_OK;
  int page_len = 0;
  int i;
  char *force_host_header = NULL;
  struct curl_slist *host = NULL;
  char addrstr[100];
  char dnscache[DEFAULT_BUFFER_SIZE];

  /* initialize curl */
  if (curl_global_init (CURL_GLOBAL_DEFAULT) != CURLE_OK)
    die (STATE_UNKNOWN, "HTTP UNKNOWN - curl_global_init failed\n");

  if ((curl = curl_easy_init()) == NULL)
    die (STATE_UNKNOWN, "HTTP UNKNOWN - curl_easy_init failed\n");

  if (verbose >= 1)
    handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_VERBOSE, TRUE), "CURLOPT_VERBOSE");

  /* print everything on stdout like check_http would do */
  handle_curl_option_return_code (curl_easy_setopt(curl, CURLOPT_STDERR, stdout), "CURLOPT_STDERR");

  if (automatic_decompression)
#if LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 21, 6)
    handle_curl_option_return_code (curl_easy_setopt(curl, CURLOPT_ACCEPT_ENCODING, ""), "CURLOPT_ACCEPT_ENCODING");
#else
    handle_curl_option_return_code (curl_easy_setopt(curl, CURLOPT_ENCODING, ""), "CURLOPT_ENCODING");
#endif /* LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 21, 6) */

  /* initialize buffer for body of the answer */
  if (curlhelp_initwritebuffer(&body_buf) < 0)
    die (STATE_UNKNOWN, "HTTP CRITICAL - out of memory allocating buffer for body\n");
  handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_WRITEFUNCTION, (curl_write_callback)curlhelp_buffer_write_callback), "CURLOPT_WRITEFUNCTION");
  handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_WRITEDATA, (void *)&body_buf), "CURLOPT_WRITEDATA");

  /* initialize buffer for header of the answer */
  if (curlhelp_initwritebuffer( &header_buf ) < 0)
    die (STATE_UNKNOWN, "HTTP CRITICAL - out of memory allocating buffer for header\n" );
  handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_HEADERFUNCTION, (curl_write_callback)curlhelp_buffer_write_callback), "CURLOPT_HEADERFUNCTION");
  handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_WRITEHEADER, (void *)&header_buf), "CURLOPT_WRITEHEADER");

  /* set the error buffer */
  handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_ERRORBUFFER, errbuf), "CURLOPT_ERRORBUFFER");

  /* set timeouts */
  handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_CONNECTTIMEOUT, socket_timeout), "CURLOPT_CONNECTTIMEOUT");
  handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_TIMEOUT, socket_timeout), "CURLOPT_TIMEOUT");

  // fill dns resolve cache to make curl connect to the given server_address instead of the host_name, only required for ssl, because we use the host_name later on to make SNI happy
  if(use_ssl && host_name != NULL) {
      if ( (res=lookup_host (server_address, addrstr, 100)) != 0) {
        snprintf (msg, DEFAULT_BUFFER_SIZE, _("Unable to lookup IP address for '%s': getaddrinfo returned %d - %s"),
          server_address, res, gai_strerror (res));
        die (STATE_CRITICAL, "HTTP CRITICAL - %s\n", msg);
      }
      snprintf (dnscache, DEFAULT_BUFFER_SIZE, "%s:%d:%s", host_name, server_port, addrstr);
      host = curl_slist_append(NULL, dnscache);
      curl_easy_setopt(curl, CURLOPT_RESOLVE, host);
      if (verbose>=1)
        printf ("* curl CURLOPT_RESOLVE: %s\n", dnscache);
  }

  /* compose URL: use the address we want to connect to, set Host: header later */
  snprintf (url, DEFAULT_BUFFER_SIZE, "%s://%s:%d%s",
      use_ssl ? "https" : "http",
      use_ssl & host_name != NULL ? host_name : server_address,
      server_port,
      server_url
  );

  if (verbose>=1)
    printf ("* curl CURLOPT_URL: %s\n", url);
  handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_URL, url), "CURLOPT_URL");

  /* extract proxy information for legacy proxy https requests */
  if (!strcmp(http_method, "CONNECT") || strstr(server_url, "http") == server_url) {
    handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_PROXY, server_address), "CURLOPT_PROXY");
    handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_PROXYPORT, (long)server_port), "CURLOPT_PROXYPORT");
    if (verbose>=2)
      printf ("* curl CURLOPT_PROXY: %s:%d\n", server_address, server_port);
    http_method = "GET";
    handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_URL, server_url), "CURLOPT_URL");
  }

  /* disable body for HEAD request */
  if (http_method && !strcmp (http_method, "HEAD" )) {
    no_body = TRUE;
  }

  /* set HTTP protocol version */
  handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_HTTP_VERSION, curl_http_version), "CURLOPT_HTTP_VERSION");

  /* set HTTP method */
  if (http_method) {
    if (!strcmp(http_method, "POST"))
      handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_POST, 1), "CURLOPT_POST");
    else if (!strcmp(http_method, "PUT"))
      handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_UPLOAD, 1), "CURLOPT_UPLOAD");
    else
      handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_CUSTOMREQUEST, http_method), "CURLOPT_CUSTOMREQUEST");
  }

  /* check if Host header is explicitly set in options */
  if (http_opt_headers_count) {
    for (i = 0; i < http_opt_headers_count ; i++) {
      if (strncmp(http_opt_headers[i], "Host:", 5) == 0) {
        force_host_header = http_opt_headers[i];
      }
    }
  }

  /* set hostname (virtual hosts), not needed if CURLOPT_CONNECT_TO is used, but left in anyway */
  if(host_name != NULL && force_host_header == NULL) {
    if((virtual_port != HTTP_PORT && !use_ssl) || (virtual_port != HTTPS_PORT && use_ssl)) {
      snprintf(http_header, DEFAULT_BUFFER_SIZE, "Host: %s:%d", host_name, virtual_port);
    } else {
      snprintf(http_header, DEFAULT_BUFFER_SIZE, "Host: %s", host_name);
    }
    header_list = curl_slist_append (header_list, http_header);
  }

  /* always close connection, be nice to servers */
  snprintf (http_header, DEFAULT_BUFFER_SIZE, "Connection: close");
  header_list = curl_slist_append (header_list, http_header);

  /* attach additional headers supplied by the user */
  /* optionally send any other header tag */
  if (http_opt_headers_count) {
    for (i = 0; i < http_opt_headers_count ; i++) {
      header_list = curl_slist_append (header_list, http_opt_headers[i]);
    }
    /* This cannot be free'd here because a redirection will then try to access this and segfault */
    /* Covered in a testcase in tests/check_http.t */
    /* free(http_opt_headers); */
  }

  /* set HTTP headers */
  handle_curl_option_return_code (curl_easy_setopt( curl, CURLOPT_HTTPHEADER, header_list ), "CURLOPT_HTTPHEADER");

#ifdef LIBCURL_FEATURE_SSL

  /* set SSL version, warn about unsecure or unsupported versions */
  if (use_ssl) {
    handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_SSLVERSION, ssl_version), "CURLOPT_SSLVERSION");
  }

  /* client certificate and key to present to server (SSL) */
  if (client_cert)
    handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_SSLCERT, client_cert), "CURLOPT_SSLCERT");
  if (client_privkey)
    handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_SSLKEY, client_privkey), "CURLOPT_SSLKEY");
  if (ca_cert) {
    handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_CAINFO, ca_cert), "CURLOPT_CAINFO");
  }
  if (ca_cert || verify_peer_and_host) {
    /* per default if we have a CA verify both the peer and the
     * hostname in the certificate, can be switched off later */
    handle_curl_option_return_code (curl_easy_setopt( curl, CURLOPT_SSL_VERIFYPEER, 1), "CURLOPT_SSL_VERIFYPEER");
    handle_curl_option_return_code (curl_easy_setopt( curl, CURLOPT_SSL_VERIFYHOST, 2), "CURLOPT_SSL_VERIFYHOST");
  } else {
    /* backward-compatible behaviour, be tolerant in checks
     * TODO: depending on more options have aspects we want
     * to be less tolerant about ssl verfications
     */
    handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_SSL_VERIFYPEER, 0), "CURLOPT_SSL_VERIFYPEER");
    handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_SSL_VERIFYHOST, 0), "CURLOPT_SSL_VERIFYHOST");
  }

  /* detect SSL library used by libcurl */
  ssl_library = curlhelp_get_ssl_library (curl);

  /* try hard to get a stack of certificates to verify against */
  if (check_cert) {
#if LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 19, 1)
    /* inform curl to report back certificates */
    switch (ssl_library) {
      case CURLHELP_SSL_LIBRARY_OPENSSL:
      case CURLHELP_SSL_LIBRARY_LIBRESSL:
        /* set callback to extract certificate with OpenSSL context function (works with
         * OpenSSL-style libraries only!) */
#ifdef USE_OPENSSL
        /* libcurl and monitoring plugins built with OpenSSL, good */
        handle_curl_option_return_code (curl_easy_setopt(curl, CURLOPT_SSL_CTX_FUNCTION, sslctxfun), "CURLOPT_SSL_CTX_FUNCTION");
        is_openssl_callback = TRUE;
#else /* USE_OPENSSL */
#endif /* USE_OPENSSL */
        /* libcurl is built with OpenSSL, monitoring plugins, so falling
         * back to manually extracting certificate information */
        handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_CERTINFO, 1L), "CURLOPT_CERTINFO");
        break;

      case CURLHELP_SSL_LIBRARY_NSS:
#if LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 34, 0)
        /* NSS: support for CERTINFO is implemented since 7.34.0 */
        handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_CERTINFO, 1L), "CURLOPT_CERTINFO");
#else /* LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 34, 0) */
        die (STATE_CRITICAL, "HTTP CRITICAL - Cannot retrieve certificates (libcurl linked with SSL library '%s' is too old)\n", curlhelp_get_ssl_library_string (ssl_library));
#endif /* LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 34, 0) */
        break;

      case CURLHELP_SSL_LIBRARY_GNUTLS:
#if LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 42, 0)
        /* GnuTLS: support for CERTINFO is implemented since 7.42.0 */
        handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_CERTINFO, 1L), "CURLOPT_CERTINFO");
#else /* LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 42, 0) */
        die (STATE_CRITICAL, "HTTP CRITICAL - Cannot retrieve certificates (libcurl linked with SSL library '%s' is too old)\n", curlhelp_get_ssl_library_string (ssl_library));
#endif /* LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 42, 0) */
        break;

      case CURLHELP_SSL_LIBRARY_UNKNOWN:
      default:
        die (STATE_CRITICAL, "HTTP CRITICAL - Cannot retrieve certificates (unknown SSL library '%s', must implement first)\n", curlhelp_get_ssl_library_string (ssl_library));
        break;
    }
#else /* LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 19, 1) */
    /* old libcurl, our only hope is OpenSSL, otherwise we are out of luck */
    if (ssl_library == CURLHELP_SSL_LIBRARY_OPENSSL || ssl_library == CURLHELP_SSL_LIBRARY_LIBRESSL)
      handle_curl_option_return_code (curl_easy_setopt(curl, CURLOPT_SSL_CTX_FUNCTION, sslctxfun), "CURLOPT_SSL_CTX_FUNCTION");
    else
      die (STATE_CRITICAL, "HTTP CRITICAL - Cannot retrieve certificates (no CURLOPT_SSL_CTX_FUNCTION, no OpenSSL library or libcurl too old and has no CURLOPT_CERTINFO)\n");
#endif /* LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 19, 1) */
  }

#endif /* LIBCURL_FEATURE_SSL */

  /* set default or user-given user agent identification */
  handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_USERAGENT, user_agent), "CURLOPT_USERAGENT");

  /* proxy-authentication */
  if (strcmp(proxy_auth, ""))
    handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_PROXYUSERPWD, proxy_auth), "CURLOPT_PROXYUSERPWD");

  /* authentication */
  if (strcmp(user_auth, ""))
    handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_USERPWD, user_auth), "CURLOPT_USERPWD");

  /* TODO: parameter auth method, bitfield of following methods:
   * CURLAUTH_BASIC (default)
   * CURLAUTH_DIGEST
   * CURLAUTH_DIGEST_IE
   * CURLAUTH_NEGOTIATE
   * CURLAUTH_NTLM
   * CURLAUTH_NTLM_WB
   *
   * convenience tokens for typical sets of methods:
   * CURLAUTH_ANYSAFE: most secure, without BASIC
   * or CURLAUTH_ANY: most secure, even BASIC if necessary
   *
   * handle_curl_option_return_code (curl_easy_setopt( curl, CURLOPT_HTTPAUTH, (long)CURLAUTH_DIGEST ), "CURLOPT_HTTPAUTH");
   */

  /* handle redirections */
  if (onredirect == STATE_DEPENDENT) {
    if( followmethod == FOLLOW_LIBCURL ) {
      handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_FOLLOWLOCATION, 1), "CURLOPT_FOLLOWLOCATION");

      /* default -1 is infinite, not good, could lead to zombie plugins!
         Setting it to one bigger than maximal limit to handle errors nicely below
       */
      handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_MAXREDIRS, max_depth+1), "CURLOPT_MAXREDIRS");

      /* for now allow only http and https (we are a http(s) check plugin in the end) */
#if LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 19, 4)
      handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_REDIR_PROTOCOLS, CURLPROTO_HTTP | CURLPROTO_HTTPS), "CURLOPT_REDIRECT_PROTOCOLS");
#endif /* LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 19, 4) */

      /* TODO: handle the following aspects of redirection, make them
       * command line options too later:
        CURLOPT_POSTREDIR: method switch
        CURLINFO_REDIRECT_URL: custom redirect option
        CURLOPT_REDIRECT_PROTOCOLS: allow people to step outside safe protocols
        CURLINFO_REDIRECT_COUNT: get the number of redirects, print it, maybe a range option here is nice like for expected page size?
      */
    } else {
      /* old style redirection is handled below */
    }
  }

  /* no-body */
  if (no_body)
    handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_NOBODY, 1), "CURLOPT_NOBODY");

  /* IPv4 or IPv6 forced DNS resolution */
  if (address_family == AF_UNSPEC)
    handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_WHATEVER), "CURLOPT_IPRESOLVE(CURL_IPRESOLVE_WHATEVER)");
  else if (address_family == AF_INET)
    handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V4), "CURLOPT_IPRESOLVE(CURL_IPRESOLVE_V4)");
#if defined (USE_IPV6) && defined (LIBCURL_FEATURE_IPV6)
  else if (address_family == AF_INET6)
    handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V6), "CURLOPT_IPRESOLVE(CURL_IPRESOLVE_V6)");
#endif

  /* either send http POST data (any data, not only POST)*/
  if (!strcmp(http_method, "POST") ||!strcmp(http_method, "PUT")) {
    /* set content of payload for POST and PUT */
    if (http_content_type) {
      snprintf (http_header, DEFAULT_BUFFER_SIZE, "Content-Type: %s", http_content_type);
      header_list = curl_slist_append (header_list, http_header);
    }
    /* NULL indicates "HTTP Continue" in libcurl, provide an empty string
     * in case of no POST/PUT data */
    if (!http_post_data)
      http_post_data = "";
    if (!strcmp(http_method, "POST")) {
      /* POST method, set payload with CURLOPT_POSTFIELDS */
      handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_POSTFIELDS, http_post_data), "CURLOPT_POSTFIELDS");
    } else if (!strcmp(http_method, "PUT")) {
      handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_READFUNCTION, (curl_read_callback)curlhelp_buffer_read_callback), "CURLOPT_READFUNCTION");
      curlhelp_initreadbuffer (&put_buf, http_post_data, strlen (http_post_data));
      handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_READDATA, (void *)&put_buf), "CURLOPT_READDATA");
      handle_curl_option_return_code (curl_easy_setopt (curl, CURLOPT_INFILESIZE, (curl_off_t)strlen (http_post_data)), "CURLOPT_INFILESIZE");
    }
  }

  /* do the request */
  res = curl_easy_perform(curl);

  if (verbose>=2 && http_post_data)
    printf ("**** REQUEST CONTENT ****\n%s\n", http_post_data);

  /* free header and server IP resolve lists, we don't need it anymore */
  curl_slist_free_all (header_list); header_list = NULL;
  curl_slist_free_all (server_ips); server_ips = NULL;

  /* Curl errors, result in critical Nagios state */
  if (res != CURLE_OK) {
    snprintf (msg, DEFAULT_BUFFER_SIZE, _("Invalid HTTP response received from host on port %d: cURL returned %d - %s"),
      server_port, res, errbuf[0] ? errbuf : curl_easy_strerror(res));
    die (STATE_CRITICAL, "HTTP CRITICAL - %s\n", msg);
  }

  /* certificate checks */
#ifdef LIBCURL_FEATURE_SSL
  if (use_ssl == TRUE) {
    if (check_cert == TRUE) {
      if (is_openssl_callback) {
#ifdef USE_OPENSSL
        /* check certificate with OpenSSL functions, curl has been built against OpenSSL
         * and we actually have OpenSSL in the monitoring tools
         */
        result = np_net_ssl_check_certificate(cert, days_till_exp_warn, days_till_exp_crit);
        return result;
#else /* USE_OPENSSL */
        die (STATE_CRITICAL, "HTTP CRITICAL - Cannot retrieve certificates - OpenSSL callback used and not linked against OpenSSL\n");
#endif /* USE_OPENSSL */
      } else {
        int i;
        struct curl_slist *slist;

        cert_ptr.to_info = NULL;
        res = curl_easy_getinfo (curl, CURLINFO_CERTINFO, &cert_ptr.to_info);
        if (!res && cert_ptr.to_info) {
#ifdef USE_OPENSSL
          /* We have no OpenSSL in libcurl, but we can use OpenSSL for X509 cert parsing
           * We only check the first certificate and assume it's the one of the server
           */
          const char* raw_cert = NULL;
          for (i = 0; i < cert_ptr.to_certinfo->num_of_certs; i++) {
            for (slist = cert_ptr.to_certinfo->certinfo[i]; slist; slist = slist->next) {
              if (verbose >= 2)
                printf ("%d ** %s\n", i, slist->data);
              if (strncmp (slist->data, "Cert:", 5) == 0) {
                raw_cert = &slist->data[5];
                goto GOT_FIRST_CERT;
              }
            }
          }
GOT_FIRST_CERT:
          if (!raw_cert) {
            snprintf (msg, DEFAULT_BUFFER_SIZE, _("Cannot retrieve certificates from CERTINFO information - certificate data was empty"));
            die (STATE_CRITICAL, "HTTP CRITICAL - %s\n", msg);
          }
          BIO* cert_BIO = BIO_new (BIO_s_mem());
          BIO_write (cert_BIO, raw_cert, strlen(raw_cert));
          cert = PEM_read_bio_X509 (cert_BIO, NULL, NULL, NULL);
          if (!cert) {
            snprintf (msg, DEFAULT_BUFFER_SIZE, _("Cannot read certificate from CERTINFO information - BIO error"));
            die (STATE_CRITICAL, "HTTP CRITICAL - %s\n", msg);
          }
          BIO_free (cert_BIO);
          result = np_net_ssl_check_certificate(cert, days_till_exp_warn, days_till_exp_crit);
          return result;
#else /* USE_OPENSSL */
          /* We assume we don't have OpenSSL and np_net_ssl_check_certificate at our disposal,
           * so we use the libcurl CURLINFO data
           */
          result = net_noopenssl_check_certificate(&cert_ptr, days_till_exp_warn, days_till_exp_crit);
          return result;
#endif /* USE_OPENSSL */
        } else {
          snprintf (msg, DEFAULT_BUFFER_SIZE, _("Cannot retrieve certificates - cURL returned %d - %s"),
            res, curl_easy_strerror(res));
          die (STATE_CRITICAL, "HTTP CRITICAL - %s\n", msg);
        }
      }
    }
  }
#endif /* LIBCURL_FEATURE_SSL */

  /* we got the data and we executed the request in a given time, so we can append
   * performance data to the answer always
   */
  handle_curl_option_return_code (curl_easy_getinfo (curl, CURLINFO_TOTAL_TIME, &total_time), "CURLINFO_TOTAL_TIME");
  page_len = get_content_length(&header_buf, &body_buf);
  if(show_extended_perfdata) {
    handle_curl_option_return_code (curl_easy_getinfo(curl, CURLINFO_CONNECT_TIME, &time_connect), "CURLINFO_CONNECT_TIME");
    handle_curl_option_return_code (curl_easy_getinfo(curl, CURLINFO_APPCONNECT_TIME, &time_appconnect), "CURLINFO_APPCONNECT_TIME");
    handle_curl_option_return_code (curl_easy_getinfo(curl, CURLINFO_PRETRANSFER_TIME, &time_headers), "CURLINFO_PRETRANSFER_TIME");
    handle_curl_option_return_code (curl_easy_getinfo(curl, CURLINFO_STARTTRANSFER_TIME, &time_firstbyte), "CURLINFO_STARTTRANSFER_TIME");
    snprintf(perfstring, DEFAULT_BUFFER_SIZE, "%s %s %s %s %s %s %s",
      perfd_time(total_time),
      perfd_size(page_len),
      perfd_time_connect(time_connect),
      use_ssl == TRUE ? perfd_time_ssl (time_appconnect-time_connect) : "",
      perfd_time_headers(time_headers - time_appconnect),
      perfd_time_firstbyte(time_firstbyte - time_headers),
      perfd_time_transfer(total_time-time_firstbyte)
    );
  } else {
    snprintf(perfstring, DEFAULT_BUFFER_SIZE, "%s %s",
      perfd_time(total_time),
      perfd_size(page_len)
    );
  }

  /* return a CRITICAL status if we couldn't read any data */
  if (strlen(header_buf.buf) == 0 && strlen(body_buf.buf) == 0)
    die (STATE_CRITICAL, _("HTTP CRITICAL - No header received from host\n"));

  /* get status line of answer, check sanity of HTTP code */
  if (curlhelp_parse_statusline (header_buf.buf, &status_line) < 0) {
    snprintf (msg, DEFAULT_BUFFER_SIZE, "Unparsable status line in %.3g seconds response time|%s\n",
      total_time, perfstring);
    /* we cannot know the major/minor version here for sure as we cannot parse the first line */
    die (STATE_CRITICAL, "HTTP CRITICAL HTTP/x.x %ld unknown - %s", code, msg);
  }

  /* get result code from cURL */
  handle_curl_option_return_code (curl_easy_getinfo (curl, CURLINFO_RESPONSE_CODE, &code), "CURLINFO_RESPONSE_CODE");
  if (verbose>=2)
    printf ("* curl CURLINFO_RESPONSE_CODE is %ld\n", code);

  /* print status line, header, body if verbose */
  if (verbose >= 2) {
    printf ("**** HEADER ****\n%s\n**** CONTENT ****\n%s\n", header_buf.buf,
                (no_body ? "  [[ skipped ]]" : body_buf.buf));
  }

  /* make sure the status line matches the response we are looking for */
  if (!expected_statuscode(status_line.first_line, server_expect)) {
    if (server_port == HTTP_PORT)
      snprintf(msg, DEFAULT_BUFFER_SIZE, _("Invalid HTTP response received from host: %s\n"), status_line.first_line);
    else
      snprintf(msg, DEFAULT_BUFFER_SIZE, _("Invalid HTTP response received from host on port %d: %s\n"), server_port, status_line.first_line);
    die (STATE_CRITICAL, "HTTP CRITICAL - %s%s%s", msg,
      show_body ? "\n" : "",
      show_body ? body_buf.buf : "");
  }

  if( server_expect_yn  )  {
    snprintf(msg, DEFAULT_BUFFER_SIZE, _("Status line output matched \"%s\" - "), server_expect);
    if (verbose)
      printf ("%s\n",msg);
    result = STATE_OK;
  }
  else {
    /* illegal return codes result in a critical state */
    if (code >= 600 || code < 100) {
      die (STATE_CRITICAL, _("HTTP CRITICAL: Invalid Status (%d, %.40s)\n"), status_line.http_code, status_line.msg);
    /* server errors result in a critical state */
        } else if (code >= 500) {
      result = STATE_CRITICAL;
        /* client errors result in a warning state */
    } else if (code >= 400) {
      result = STATE_WARNING;
    /* check redirected page if specified */
    } else if (code >= 300) {
      if (onredirect == STATE_DEPENDENT) {
        if( followmethod == FOLLOW_LIBCURL ) {
          code = status_line.http_code;
        } else {
          /* old check_http style redirection, if we come
           * back here, we are in the same status as with
           * the libcurl method
           */
          redir (&header_buf);
        }
      } else {
        /* this is a specific code in the command line to
         * be returned when a redirection is encoutered
         */
      }
      result = max_state_alt (onredirect, result);
    /* all other codes are considered ok */
    } else {
      result = STATE_OK;
    }
  }

  /* libcurl redirection internally, handle error states here */
  if( followmethod == FOLLOW_LIBCURL ) {
    handle_curl_option_return_code (curl_easy_getinfo (curl, CURLINFO_REDIRECT_COUNT, &redir_depth), "CURLINFO_REDIRECT_COUNT");
    if (verbose >= 2)
      printf(_("* curl LIBINFO_REDIRECT_COUNT is %d\n"), redir_depth);
    if (redir_depth > max_depth) {
      snprintf (msg, DEFAULT_BUFFER_SIZE, "maximum redirection depth %d exceeded in libcurl",
        max_depth);
      die (STATE_WARNING, "HTTP WARNING - %s", msg);
    }
  }

  /* check status codes, set exit status accordingly */
  if( status_line.http_code != code ) {
    die (STATE_CRITICAL, _("HTTP CRITICAL %s %d %s - different HTTP codes (cUrl has %ld)\n"),
      string_statuscode (status_line.http_major, status_line.http_minor),
      status_line.http_code, status_line.msg, code);
  }

  if (maximum_age >= 0) {
    result = max_state_alt(check_document_dates(&header_buf, &msg), result);
  }

  /* Page and Header content checks go here */

  if (strlen (header_expect)) {
    if (!strstr (header_buf.buf, header_expect)) {
      strncpy(&output_header_search[0],header_expect,sizeof(output_header_search));
      if(output_header_search[sizeof(output_header_search)-1]!='\0') {
        bcopy("...",&output_header_search[sizeof(output_header_search)-4],4);
      }
      snprintf (msg, DEFAULT_BUFFER_SIZE, _("%sheader '%s' not found on '%s://%s:%d%s', "), msg, output_header_search, use_ssl ? "https" : "http", host_name ? host_name : server_address, server_port, server_url);
      result = STATE_CRITICAL;
    }
  }

  if (strlen (string_expect)) {
    if (!strstr (body_buf.buf, string_expect)) {
      strncpy(&output_string_search[0],string_expect,sizeof(output_string_search));
      if(output_string_search[sizeof(output_string_search)-1]!='\0') {
        bcopy("...",&output_string_search[sizeof(output_string_search)-4],4);
      }
      snprintf (msg, DEFAULT_BUFFER_SIZE, _("%sstring '%s' not found on '%s://%s:%d%s', "), msg, output_string_search, use_ssl ? "https" : "http", host_name ? host_name : server_address, server_port, server_url);
      result = STATE_CRITICAL;
    }
  }

  if (strlen (regexp)) {
    errcode = regexec (&preg, body_buf.buf, REGS, pmatch, 0);
    if ((errcode == 0 && invert_regex == 0) || (errcode == REG_NOMATCH && invert_regex == 1)) {
      /* OK - No-op to avoid changing the logic around it */
      result = max_state_alt(STATE_OK, result);
    }
    else if ((errcode == REG_NOMATCH && invert_regex == 0) || (errcode == 0 && invert_regex == 1)) {
      if (invert_regex == 0)
        snprintf (msg, DEFAULT_BUFFER_SIZE, _("%spattern not found, "), msg);
      else
        snprintf (msg, DEFAULT_BUFFER_SIZE, _("%spattern found, "), msg);
      result = STATE_CRITICAL;
    }
    else {
      regerror (errcode, &preg, errbuf, MAX_INPUT_BUFFER);
      snprintf (msg, DEFAULT_BUFFER_SIZE, _("%sExecute Error: %s, "), msg, errbuf);
      result = STATE_UNKNOWN;
    }
  }

  /* make sure the page is of an appropriate size */
  if ((max_page_len > 0) && (page_len > max_page_len)) {
    snprintf (msg, DEFAULT_BUFFER_SIZE, _("%spage size %d too large, "), msg, page_len);
    result = max_state_alt(STATE_WARNING, result);
  } else if ((min_page_len > 0) && (page_len < min_page_len)) {
    snprintf (msg, DEFAULT_BUFFER_SIZE, _("%spage size %d too small, "), msg, page_len);
    result = max_state_alt(STATE_WARNING, result);
  }

  /* -w, -c: check warning and critical level */
  result = max_state_alt(get_status(total_time, thlds), result);

  /* Cut-off trailing characters */
  if(msg[strlen(msg)-2] == ',')
    msg[strlen(msg)-2] = '\0';
  else
    msg[strlen(msg)-3] = '\0';

  /* TODO: separate _() msg and status code: die (result, "HTTP %s: %s\n", state_text(result), msg); */
  die (result, "HTTP %s: %s %d %s%s%s - %d bytes in %.3f second response time %s|%s\n%s%s",
    state_text(result), string_statuscode (status_line.http_major, status_line.http_minor),
    status_line.http_code, status_line.msg,
    strlen(msg) > 0 ? " - " : "",
    msg, page_len, total_time,
    (display_html ? "</A>" : ""),
    perfstring,
    (show_body ? body_buf.buf : ""),
    (show_body ? "\n" : "") );

  /* proper cleanup after die? */
  curlhelp_free_statusline(&status_line);
  curl_easy_cleanup (curl);
  curl_global_cleanup ();
  curlhelp_freewritebuffer (&body_buf);
  curlhelp_freewritebuffer (&header_buf);
  if (!strcmp (http_method, "PUT")) {
    curlhelp_freereadbuffer (&put_buf);
  }

  return result;
}

int
uri_strcmp (const UriTextRangeA range, const char* s)
{
  if (!range.first) return -1;
  if (range.afterLast - range.first < strlen (s)) return -1;
  return strncmp (s, range.first, min( range.afterLast - range.first, strlen (s)));
}

char*
uri_string (const UriTextRangeA range, char* buf, size_t buflen)
{
  if (!range.first) return "(null)";
  strncpy (buf, range.first, max (buflen-1, range.afterLast - range.first));
  buf[max (buflen-1, range.afterLast - range.first)] = '\0';
  buf[range.afterLast - range.first] = '\0';
  return buf;
}

void
redir (curlhelp_write_curlbuf* header_buf)
{
  char *location = NULL;
  curlhelp_statusline status_line;
  struct phr_header headers[255];
  size_t nof_headers = 255;
  size_t msglen;
  char buf[DEFAULT_BUFFER_SIZE];
  char ipstr[INET_ADDR_MAX_SIZE];
  int new_port;
  char *new_host;
  char *new_url;

  int res = phr_parse_response (header_buf->buf, header_buf->buflen,
    &status_line.http_major, &status_line.http_minor, &status_line.http_code, &status_line.msg, &msglen,
    headers, &nof_headers, 0);

  location = get_header_value (headers, nof_headers, "location");

  if (verbose >= 2)
    printf(_("* Seen redirect location %s\n"), location);

  if (++redir_depth > max_depth)
    die (STATE_WARNING,
         _("HTTP WARNING - maximum redirection depth %d exceeded - %s%s\n"),
         max_depth, location, (display_html ? "</A>" : ""));

  UriParserStateA state;
  UriUriA uri;
  state.uri = &uri;
  if (uriParseUriA (&state, location) != URI_SUCCESS) {
    if (state.errorCode == URI_ERROR_SYNTAX) {
      die (STATE_UNKNOWN,
           _("HTTP UNKNOWN - Could not parse redirect location '%s'%s\n"),
           location, (display_html ? "</A>" : ""));
    } else if (state.errorCode == URI_ERROR_MALLOC) {
      die (STATE_UNKNOWN, _("HTTP UNKNOWN - Could not allocate URL\n"));
    }
  }

  if (verbose >= 2) {
    printf (_("** scheme: %s\n"),
      uri_string (uri.scheme, buf, DEFAULT_BUFFER_SIZE));
    printf (_("** host: %s\n"),
      uri_string (uri.hostText, buf, DEFAULT_BUFFER_SIZE));
    printf (_("** port: %s\n"),
      uri_string (uri.portText, buf, DEFAULT_BUFFER_SIZE));
    if (uri.hostData.ip4) {
      inet_ntop (AF_INET, uri.hostData.ip4->data, ipstr, sizeof (ipstr));
      printf (_("** IPv4: %s\n"), ipstr);
    }
    if (uri.hostData.ip6) {
      inet_ntop (AF_INET, uri.hostData.ip6->data, ipstr, sizeof (ipstr));
      printf (_("** IPv6: %s\n"), ipstr);
    }
    if (uri.pathHead) {
      printf (_("** path: "));
      const UriPathSegmentA* p = uri.pathHead;
      for (; p; p = p->next) {
        printf ("/%s", uri_string (p->text, buf, DEFAULT_BUFFER_SIZE));
      }
      puts ("");
    }
    if (uri.query.first) {
      printf (_("** query: %s\n"),
      uri_string (uri.query, buf, DEFAULT_BUFFER_SIZE));
    }
    if (uri.fragment.first) {
      printf (_("** fragment: %s\n"),
      uri_string (uri.fragment, buf, DEFAULT_BUFFER_SIZE));
    }
  }

  use_ssl = !uri_strcmp (uri.scheme, "https");

  /* we do a sloppy test here only, because uriparser would have failed
   * above, if the port would be invalid, we just check for MAX_PORT
   */
  if (uri.portText.first) {
    new_port = atoi (uri_string (uri.portText, buf, DEFAULT_BUFFER_SIZE));
  } else {
    new_port = HTTP_PORT;
    if (use_ssl)
      new_port = HTTPS_PORT;
  }
  if (new_port > MAX_PORT)
    die (STATE_UNKNOWN,
         _("HTTP UNKNOWN - Redirection to port above %d - %s%s\n"),
         MAX_PORT, location, display_html ? "</A>" : "");

  /* by RFC 7231 relative URLs in Location should be taken relative to
   * the original URL, so wy try to form a new absolute URL here
   */
  if (!uri.scheme.first && !uri.hostText.first) {
    new_host = strdup (host_name ? host_name : server_address);
  } else {
    new_host = strdup (uri_string (uri.hostText, buf, DEFAULT_BUFFER_SIZE));
  }

  /* compose new path */
  /* TODO: handle fragments and query part of URL */
  new_url = (char *)calloc( 1, DEFAULT_BUFFER_SIZE);
  if (uri.pathHead) {
    const UriPathSegmentA* p = uri.pathHead;
    for (; p; p = p->next) {
      strncat (new_url, "/", DEFAULT_BUFFER_SIZE);
      strncat (new_url, uri_string (p->text, buf, DEFAULT_BUFFER_SIZE), DEFAULT_BUFFER_SIZE-1);
    }
  }

  if (server_port==new_port &&
      !strncmp(server_address, new_host, MAX_IPV4_HOSTLENGTH) &&
      (host_name && !strncmp(host_name, new_host, MAX_IPV4_HOSTLENGTH)) &&
      !strcmp(server_url, new_url))
    die (STATE_CRITICAL,
         _("HTTP CRITICAL - redirection creates an infinite loop - %s://%s:%d%s%s\n"),
         use_ssl ? "https" : "http", new_host, new_port, new_url, (display_html ? "</A>" : ""));

  /* set new values for redirected request */

  if (!(followsticky & STICKY_HOST)) {
    free (server_address);
    server_address = strndup (new_host, MAX_IPV4_HOSTLENGTH);
  }
  if (!(followsticky & STICKY_PORT)) {
    server_port = (unsigned short)new_port;
  }

  free (host_name);
  host_name = strndup (new_host, MAX_IPV4_HOSTLENGTH);

  /* reset virtual port */
  virtual_port = server_port;

  free(new_host);
  free (server_url);
  server_url = new_url;

  uriFreeUriMembersA (&uri);

  if (verbose)
    printf (_("Redirection to %s://%s:%d%s\n"), use_ssl ? "https" : "http",
            host_name ? host_name : server_address, server_port, server_url);

  /* TODO: the hash component MUST be taken from the original URL and
   * attached to the URL in Location
   */

  check_http ();
}

/* check whether a file exists */
void
test_file (char *path)
{
  if (access(path, R_OK) == 0)
    return;
  usage2 (_("file does not exist or is not readable"), path);
}

int
process_arguments (int argc, char **argv)
{
  char *p;
  int c = 1;
  char *temp;

  enum {
    INVERT_REGEX = CHAR_MAX + 1,
    SNI_OPTION,
    MAX_REDIRS_OPTION,
    CA_CERT_OPTION,
    HTTP_VERSION_OPTION,
    AUTOMATIC_DECOMPRESSION
  };

  int option = 0;
  int got_plus = 0;
  static struct option longopts[] = {
    STD_LONG_OPTS,
    {"link", no_argument, 0, 'L'},
    {"nohtml", no_argument, 0, 'n'},
    {"ssl", optional_argument, 0, 'S'},
    {"sni", no_argument, 0, SNI_OPTION},
    {"post", required_argument, 0, 'P'},
    {"method", required_argument, 0, 'j'},
    {"IP-address", required_argument, 0, 'I'},
    {"url", required_argument, 0, 'u'},
    {"port", required_argument, 0, 'p'},
    {"authorization", required_argument, 0, 'a'},
    {"proxy-authorization", required_argument, 0, 'b'},
    {"header-string", required_argument, 0, 'd'},
    {"string", required_argument, 0, 's'},
    {"expect", required_argument, 0, 'e'},
    {"regex", required_argument, 0, 'r'},
    {"ereg", required_argument, 0, 'r'},
    {"eregi", required_argument, 0, 'R'},
    {"linespan", no_argument, 0, 'l'},
    {"onredirect", required_argument, 0, 'f'},
    {"certificate", required_argument, 0, 'C'},
    {"client-cert", required_argument, 0, 'J'},
    {"private-key", required_argument, 0, 'K'},
    {"ca-cert", required_argument, 0, CA_CERT_OPTION},
    {"verify-cert", no_argument, 0, 'D'},
    {"useragent", required_argument, 0, 'A'},
    {"header", required_argument, 0, 'k'},
    {"no-body", no_argument, 0, 'N'},
    {"max-age", required_argument, 0, 'M'},
    {"content-type", required_argument, 0, 'T'},
    {"pagesize", required_argument, 0, 'm'},
    {"invert-regex", no_argument, NULL, INVERT_REGEX},
    {"use-ipv4", no_argument, 0, '4'},
    {"use-ipv6", no_argument, 0, '6'},
    {"extended-perfdata", no_argument, 0, 'E'},
    {"show-body", no_argument, 0, 'B'},
    {"max-redirs", required_argument, 0, MAX_REDIRS_OPTION},
    {"http-version", required_argument, 0, HTTP_VERSION_OPTION},
    {"enable-automatic-decompression", no_argument, 0, AUTOMATIC_DECOMPRESSION},
    {0, 0, 0, 0}
  };

  if (argc < 2)
    return ERROR;

  /* support check_http compatible arguments */
  for (c = 1; c < argc; c++) {
    if (strcmp ("-to", argv[c]) == 0)
      strcpy (argv[c], "-t");
    if (strcmp ("-hn", argv[c]) == 0)
      strcpy (argv[c], "-H");
    if (strcmp ("-wt", argv[c]) == 0)
      strcpy (argv[c], "-w");
    if (strcmp ("-ct", argv[c]) == 0)
      strcpy (argv[c], "-c");
    if (strcmp ("-nohtml", argv[c]) == 0)
      strcpy (argv[c], "-n");
  }

  server_url = strdup(DEFAULT_SERVER_URL);

  while (1) {
    c = getopt_long (argc, argv, "Vvh46t:c:w:A:k:H:P:j:T:I:a:b:d:e:p:s:R:r:u:f:C:J:K:DnlLS::m:M:NEB", longopts, &option);
    if (c == -1 || c == EOF || c == 1)
      break;

    switch (c) {
    case 'h':
      print_help();
      exit(STATE_UNKNOWN);
      break;
    case 'V':
      print_revision(progname, NP_VERSION);
      print_curl_version();
      exit(STATE_UNKNOWN);
      break;
    case 'v':
      verbose++;
      break;
    case 't': /* timeout period */
      if (!is_intnonneg (optarg))
        usage2 (_("Timeout interval must be a positive integer"), optarg);
      else
        socket_timeout = (int)strtol (optarg, NULL, 10);
      break;
    case 'c': /* critical time threshold */
      critical_thresholds = optarg;
      break;
    case 'w': /* warning time threshold */
      warning_thresholds = optarg;
      break;
    case 'H': /* virtual host */
      host_name = strdup (optarg);
      if (host_name[0] == '[') {
        if ((p = strstr (host_name, "]:")) != NULL) { /* [IPv6]:port */
          virtual_port = atoi (p + 2);
          /* cut off the port */
          host_name_length = strlen (host_name) - strlen (p) - 1;
          free (host_name);
          host_name = strndup (optarg, host_name_length);
	}
      } else if ((p = strchr (host_name, ':')) != NULL
                 && strchr (++p, ':') == NULL) { /* IPv4:port or host:port */
          virtual_port = atoi (p);
          /* cut off the port */
          host_name_length = strlen (host_name) - strlen (p) - 1;
          free (host_name);
          host_name = strndup (optarg, host_name_length);
        }
      break;
    case 'I': /* internet address */
      server_address = strdup (optarg);
      break;
    case 'u': /* URL path */
      server_url = strdup (optarg);
      break;
    case 'p': /* Server port */
      if (!is_intnonneg (optarg))
        usage2 (_("Invalid port number, expecting a non-negative number"), optarg);
      else {
        if( strtol(optarg, NULL, 10) > MAX_PORT)
          usage2 (_("Invalid port number, supplied port number is too big"), optarg);
        server_port = (unsigned short)strtol(optarg, NULL, 10);
        specify_port = TRUE;
      }
      break;
    case 'a': /* authorization info */
      strncpy (user_auth, optarg, MAX_INPUT_BUFFER - 1);
      user_auth[MAX_INPUT_BUFFER - 1] = 0;
      break;
    case 'b': /* proxy-authorization info */
      strncpy (proxy_auth, optarg, MAX_INPUT_BUFFER - 1);
      proxy_auth[MAX_INPUT_BUFFER - 1] = 0;
      break;
    case 'P': /* HTTP POST data in URL encoded format; ignored if settings already */
      if (! http_post_data)
        http_post_data = strdup (optarg);
      if (! http_method)
        http_method = strdup("POST");
      break;
    case 'j': /* Set HTTP method */
      if (http_method)
        free(http_method);
      http_method = strdup (optarg);
      break;
    case 'A': /* useragent */
      strncpy (user_agent, optarg, DEFAULT_BUFFER_SIZE);
      user_agent[DEFAULT_BUFFER_SIZE-1] = '\0';
      break;
    case 'k': /* Additional headers */
      if (http_opt_headers_count == 0)
        http_opt_headers = malloc (sizeof (char *) * (++http_opt_headers_count));
      else
        http_opt_headers = realloc (http_opt_headers, sizeof (char *) * (++http_opt_headers_count));
      http_opt_headers[http_opt_headers_count - 1] = optarg;
      break;
    case 'L': /* show html link */
      display_html = TRUE;
      break;
    case 'n': /* do not show html link */
      display_html = FALSE;
      break;
    case 'C': /* Check SSL cert validity */
#ifdef LIBCURL_FEATURE_SSL
      if ((temp=strchr(optarg,','))!=NULL) {
        *temp='\0';
        if (!is_intnonneg (optarg))
          usage2 (_("Invalid certificate expiration period"), optarg);
        days_till_exp_warn = atoi(optarg);
        *temp=',';
        temp++;
        if (!is_intnonneg (temp))
          usage2 (_("Invalid certificate expiration period"), temp);
        days_till_exp_crit = atoi (temp);
      }
      else {
        days_till_exp_crit=0;
        if (!is_intnonneg (optarg))
          usage2 (_("Invalid certificate expiration period"), optarg);
        days_till_exp_warn = atoi (optarg);
      }
      check_cert = TRUE;
      goto enable_ssl;
#endif
    case 'J': /* use client certificate */
#ifdef LIBCURL_FEATURE_SSL
      test_file(optarg);
      client_cert = optarg;
      goto enable_ssl;
#endif
    case 'K': /* use client private key */
#ifdef LIBCURL_FEATURE_SSL
      test_file(optarg);
      client_privkey = optarg;
      goto enable_ssl;
#endif
#ifdef LIBCURL_FEATURE_SSL
    case CA_CERT_OPTION: /* use CA chain file */
      test_file(optarg);
      ca_cert = optarg;
      goto enable_ssl;
#endif
#ifdef LIBCURL_FEATURE_SSL
    case 'D': /* verify peer certificate & host */
      verify_peer_and_host = TRUE;
      break;
#endif
    case 'S': /* use SSL */
#ifdef LIBCURL_FEATURE_SSL
    enable_ssl:
      use_ssl = TRUE;
      /* ssl_version initialized to CURL_SSLVERSION_DEFAULT as a default.
       * Only set if it's non-zero.  This helps when we include multiple
       * parameters, like -S and -C combinations */
      ssl_version = CURL_SSLVERSION_DEFAULT;
      if (c=='S' && optarg != NULL) {
        char *plus_ptr = strchr(optarg, '+');
        if (plus_ptr) {
          got_plus = 1;
          *plus_ptr = '\0';
        }

        if (optarg[0] == '2')
          ssl_version = CURL_SSLVERSION_SSLv2;
        else if (optarg[0] == '3')
          ssl_version = CURL_SSLVERSION_SSLv3;
        else if (!strcmp (optarg, "1") || !strcmp (optarg, "1.0"))
#if LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 34, 0)
          ssl_version = CURL_SSLVERSION_TLSv1_0;
#else
          ssl_version = CURL_SSLVERSION_DEFAULT;
#endif /* LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 34, 0) */
        else if (!strcmp (optarg, "1.1"))
#if LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 34, 0)
          ssl_version = CURL_SSLVERSION_TLSv1_1;
#else
          ssl_version = CURL_SSLVERSION_DEFAULT;
#endif /* LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 34, 0) */
        else if (!strcmp (optarg, "1.2"))
#if LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 34, 0)
          ssl_version = CURL_SSLVERSION_TLSv1_2;
#else
          ssl_version = CURL_SSLVERSION_DEFAULT;
#endif /* LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 34, 0) */
        else if (!strcmp (optarg, "1.3"))
#if LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 52, 0)
          ssl_version = CURL_SSLVERSION_TLSv1_3;
#else
          ssl_version = CURL_SSLVERSION_DEFAULT;
#endif /* LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 52, 0) */
        else
          usage4 (_("Invalid option - Valid SSL/TLS versions: 2, 3, 1, 1.1, 1.2, 1.3 (with optional '+' suffix)"));
      }
#if LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 54, 0)
      if (got_plus) {
        switch (ssl_version) {
          case CURL_SSLVERSION_TLSv1_3:
            ssl_version |= CURL_SSLVERSION_MAX_TLSv1_3;
            break;
          case CURL_SSLVERSION_TLSv1_2:
          case CURL_SSLVERSION_TLSv1_1:
          case CURL_SSLVERSION_TLSv1_0:
            ssl_version |= CURL_SSLVERSION_MAX_DEFAULT;
            break;
        }
      } else {
        switch (ssl_version) {
          case CURL_SSLVERSION_TLSv1_3:
            ssl_version |= CURL_SSLVERSION_MAX_TLSv1_3;
            break;
          case CURL_SSLVERSION_TLSv1_2:
            ssl_version |= CURL_SSLVERSION_MAX_TLSv1_2;
            break;
          case CURL_SSLVERSION_TLSv1_1:
            ssl_version |= CURL_SSLVERSION_MAX_TLSv1_1;
            break;
          case CURL_SSLVERSION_TLSv1_0:
            ssl_version |= CURL_SSLVERSION_MAX_TLSv1_0;
            break;
        }
      }
#endif /* LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 54, 0) */
      if (verbose >= 2)
        printf(_("* Set SSL/TLS version to %d\n"), ssl_version);
      if (specify_port == FALSE)
        server_port = HTTPS_PORT;
      break;
#else /* LIBCURL_FEATURE_SSL */
      /* -C -J and -K fall through to here without SSL */
      usage4 (_("Invalid option - SSL is not available"));
      break;
    case SNI_OPTION: /* --sni is parsed, but ignored, the default is TRUE with libcurl */
      use_sni = TRUE;
      break;
#endif /* LIBCURL_FEATURE_SSL */
    case MAX_REDIRS_OPTION:
      if (!is_intnonneg (optarg))
        usage2 (_("Invalid max_redirs count"), optarg);
      else {
        max_depth = atoi (optarg);
      }
      break;    
    case 'f': /* onredirect */
      if (!strcmp (optarg, "ok"))
        onredirect = STATE_OK;
      else if (!strcmp (optarg, "warning"))
        onredirect = STATE_WARNING;
      else if (!strcmp (optarg, "critical"))
        onredirect = STATE_CRITICAL;
      else if (!strcmp (optarg, "unknown"))
        onredirect = STATE_UNKNOWN;
      else if (!strcmp (optarg, "follow"))
        onredirect = STATE_DEPENDENT;
      else if (!strcmp (optarg, "stickyport"))
        onredirect = STATE_DEPENDENT, followmethod = FOLLOW_HTTP_CURL, followsticky = STICKY_HOST|STICKY_PORT;
      else if (!strcmp (optarg, "sticky"))
        onredirect = STATE_DEPENDENT, followmethod = FOLLOW_HTTP_CURL, followsticky = STICKY_HOST;
      else if (!strcmp (optarg, "follow"))
        onredirect = STATE_DEPENDENT, followmethod = FOLLOW_HTTP_CURL, followsticky = STICKY_NONE;
      else if (!strcmp (optarg, "curl"))
        onredirect = STATE_DEPENDENT, followmethod = FOLLOW_LIBCURL;
      else usage2 (_("Invalid onredirect option"), optarg);
      if (verbose >= 2)
        printf(_("* Following redirects set to %s\n"), state_text(onredirect));
      break;
    case 'd': /* string or substring */
      strncpy (header_expect, optarg, MAX_INPUT_BUFFER - 1);
      header_expect[MAX_INPUT_BUFFER - 1] = 0;
      break;
    case 's': /* string or substring */
      strncpy (string_expect, optarg, MAX_INPUT_BUFFER - 1);
      string_expect[MAX_INPUT_BUFFER - 1] = 0;
      break;
    case 'e': /* string or substring */
      strncpy (server_expect, optarg, MAX_INPUT_BUFFER - 1);
      server_expect[MAX_INPUT_BUFFER - 1] = 0;
      server_expect_yn = 1;
      break;
    case 'T': /* Content-type */
      http_content_type = strdup (optarg);
     break;
    case 'l': /* linespan */
      cflags &= ~REG_NEWLINE;
      break;
    case 'R': /* regex */
      cflags |= REG_ICASE;
    case 'r': /* regex */
      strncpy (regexp, optarg, MAX_RE_SIZE - 1);
      regexp[MAX_RE_SIZE - 1] = 0;
      errcode = regcomp (&preg, regexp, cflags);
      if (errcode != 0) {
        (void) regerror (errcode, &preg, errbuf, MAX_INPUT_BUFFER);
        printf (_("Could Not Compile Regular Expression: %s"), errbuf);
        return ERROR;
      }
      break;
    case INVERT_REGEX:
      invert_regex = 1;
      break;
    case '4':
      address_family = AF_INET;
      break;
    case '6':
#if defined (USE_IPV6) && defined (LIBCURL_FEATURE_IPV6)
      address_family = AF_INET6;
#else
      usage4 (_("IPv6 support not available"));
#endif
      break;
    case 'm': /* min_page_length */
      {
      char *tmp;
      if (strchr(optarg, ':') != (char *)NULL) {
        /* range, so get two values, min:max */
        tmp = strtok(optarg, ":");
        if (tmp == NULL) {
          printf("Bad format: try \"-m min:max\"\n");
          exit (STATE_WARNING);
        } else
          min_page_len = atoi(tmp);

        tmp = strtok(NULL, ":");
        if (tmp == NULL) {
          printf("Bad format: try \"-m min:max\"\n");
          exit (STATE_WARNING);
        } else
          max_page_len = atoi(tmp);
      } else
        min_page_len = atoi (optarg);
      break;
      }
    case 'N': /* no-body */
      no_body = TRUE;
      break;
    case 'M': /* max-age */
    {
      int L = strlen(optarg);
      if (L && optarg[L-1] == 'm')
        maximum_age = atoi (optarg) * 60;
      else if (L && optarg[L-1] == 'h')
        maximum_age = atoi (optarg) * 60 * 60;
      else if (L && optarg[L-1] == 'd')
        maximum_age = atoi (optarg) * 60 * 60 * 24;
      else if (L && (optarg[L-1] == 's' ||
                     isdigit (optarg[L-1])))
        maximum_age = atoi (optarg);
      else {
        fprintf (stderr, "unparsable max-age: %s\n", optarg);
        exit (STATE_WARNING);
      }
      if (verbose >= 2)
        printf ("* Maximal age of document set to %d seconds\n", maximum_age);
    }
    break;
    case 'E': /* show extended perfdata */
      show_extended_perfdata = TRUE;
      break;
    case 'B': /* print body content after status line */
      show_body = TRUE;
      break;
    case HTTP_VERSION_OPTION:
      curl_http_version = CURL_HTTP_VERSION_NONE;
      if (strcmp (optarg, "1.0") == 0) {
        curl_http_version = CURL_HTTP_VERSION_1_0;
      } else if (strcmp (optarg, "1.1") == 0) {
        curl_http_version = CURL_HTTP_VERSION_1_1;
      } else if ((strcmp (optarg, "2.0") == 0) || (strcmp (optarg, "2") == 0)) {
#if LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 33, 0)
        curl_http_version = CURL_HTTP_VERSION_2_0;
#else
        curl_http_version = CURL_HTTP_VERSION_NONE;
#endif /* LIBCURL_VERSION_NUM >= MAKE_LIBCURL_VERSION(7, 33, 0) */
      } else {
        fprintf (stderr, "unkown http-version parameter: %s\n", optarg);
        exit (STATE_WARNING);
      }
      break;
    case AUTOMATIC_DECOMPRESSION:
      automatic_decompression = TRUE;
      break;
    case '?':
      /* print short usage statement if args not parsable */
      usage5 ();
      break;
    }
  }

  c = optind;

  if (server_address == NULL && c < argc)
    server_address = strdup (argv[c++]);

  if (host_name == NULL && c < argc)
    host_name = strdup (argv[c++]);

  if (server_address == NULL) {
    if (host_name == NULL)
      usage4 (_("You must specify a server address or host name"));
    else
      server_address = strdup (host_name);
  }

  set_thresholds(&thlds, warning_thresholds, critical_thresholds);

  if (critical_thresholds && thlds->critical->end>(double)socket_timeout)
    socket_timeout = (int)thlds->critical->end + 1;
  if (verbose >= 2)
    printf ("* Socket timeout set to %ld seconds\n", socket_timeout);

  if (http_method == NULL)
    http_method = strdup ("GET");

  if (client_cert && !client_privkey)
    usage4 (_("If you use a client certificate you must also specify a private key file"));

  if (virtual_port == 0)
    virtual_port = server_port;
  else {
    if ((use_ssl && server_port == HTTPS_PORT) || (!use_ssl && server_port == HTTP_PORT))
      if(specify_port == FALSE)
        server_port = virtual_port;
  }

  return TRUE;
}

char *perfd_time (double elapsed_time)
{
  return fperfdata ("time", elapsed_time, "s",
            thlds->warning?TRUE:FALSE, thlds->warning?thlds->warning->end:0,
            thlds->critical?TRUE:FALSE, thlds->critical?thlds->critical->end:0,
                   TRUE, 0, TRUE, socket_timeout);
}

char *perfd_time_connect (double elapsed_time_connect)
{
  return fperfdata ("time_connect", elapsed_time_connect, "s", FALSE, 0, FALSE, 0, FALSE, 0, TRUE, socket_timeout);
}

char *perfd_time_ssl (double elapsed_time_ssl)
{
  return fperfdata ("time_ssl", elapsed_time_ssl, "s", FALSE, 0, FALSE, 0, FALSE, 0, TRUE, socket_timeout);
}

char *perfd_time_headers (double elapsed_time_headers)
{
  return fperfdata ("time_headers", elapsed_time_headers, "s", FALSE, 0, FALSE, 0, FALSE, 0, TRUE, socket_timeout);
}

char *perfd_time_firstbyte (double elapsed_time_firstbyte)
{
  return fperfdata ("time_firstbyte", elapsed_time_firstbyte, "s", FALSE, 0, FALSE, 0, FALSE, 0, TRUE, socket_timeout);
}

char *perfd_time_transfer (double elapsed_time_transfer)
{
  return fperfdata ("time_transfer", elapsed_time_transfer, "s", FALSE, 0, FALSE, 0, FALSE, 0, TRUE, socket_timeout);
}

char *perfd_size (int page_len)
{
  return perfdata ("size", page_len, "B",
            (min_page_len>0?TRUE:FALSE), min_page_len,
            (min_page_len>0?TRUE:FALSE), 0,
            TRUE, 0, FALSE, 0);
}

void
print_help (void)
{
  print_revision (progname, NP_VERSION);

  printf ("Copyright (c) 1999 Ethan Galstad <nagios@nagios.org>\n");
  printf (COPYRIGHT, copyright, email);

  printf ("%s\n", _("This plugin tests the HTTP service on the specified host. It can test"));
  printf ("%s\n", _("normal (http) and secure (https) servers, follow redirects, search for"));
  printf ("%s\n", _("strings and regular expressions, check connection times, and report on"));
  printf ("%s\n", _("certificate expiration times."));
  printf ("\n");
  printf ("%s\n", _("It makes use of libcurl to do so. It tries to be as compatible to check_http"));
  printf ("%s\n", _("as possible."));

  printf ("\n\n");

  print_usage ();

  printf (_("NOTE: One or both of -H and -I must be specified"));

  printf ("\n");

  printf (UT_HELP_VRSN);
  printf (UT_EXTRA_OPTS);

  printf (" %s\n", "-H, --hostname=ADDRESS");
  printf ("    %s\n", _("Host name argument for servers using host headers (virtual host)"));
  printf ("    %s\n", _("Append a port to include it in the header (eg: example.com:5000)"));
  printf (" %s\n", "-I, --IP-address=ADDRESS");
  printf ("    %s\n", _("IP address or name (use numeric address if possible to bypass DNS lookup)."));
  printf (" %s\n", "-p, --port=INTEGER");
  printf ("    %s", _("Port number (default: "));
  printf ("%d)\n", HTTP_PORT);

  printf (UT_IPv46);

#ifdef LIBCURL_FEATURE_SSL
  printf (" %s\n", "-S, --ssl=VERSION[+]");
  printf ("    %s\n", _("Connect via SSL. Port defaults to 443. VERSION is optional, and prevents"));
  printf ("    %s\n", _("auto-negotiation (2 = SSLv2, 3 = SSLv3, 1 = TLSv1, 1.1 = TLSv1.1,"));
  printf ("    %s\n", _("1.2 = TLSv1.2, 1.3 = TLSv1.3). With a '+' suffix, newer versions are also accepted."));
  printf ("    %s\n", _("Note: SSLv2 and SSLv3 are deprecated and are usually disabled in libcurl"));
  printf (" %s\n", "--sni");
  printf ("    %s\n", _("Enable SSL/TLS hostname extension support (SNI)"));
#if LIBCURL_VERSION_NUM >= 0x071801
  printf ("    %s\n", _("Note: --sni is the default in libcurl as SSLv2 and SSLV3 are deprecated and"));
  printf ("    %s\n", _("      SNI only really works since TLSv1.0"));
#else
  printf ("    %s\n", _("Note: SNI is not supported in libcurl before 7.18.1"));
#endif
  printf (" %s\n", "-C, --certificate=INTEGER[,INTEGER]");
  printf ("    %s\n", _("Minimum number of days a certificate has to be valid. Port defaults to 443"));
  printf ("    %s\n", _("(when this option is used the URL is not checked.)"));
  printf (" %s\n", "-J, --client-cert=FILE");
  printf ("   %s\n", _("Name of file that contains the client certificate (PEM format)"));
  printf ("   %s\n", _("to be used in establishing the SSL session"));
  printf (" %s\n", "-K, --private-key=FILE");
  printf ("   %s\n", _("Name of file containing the private key (PEM format)"));
  printf ("   %s\n", _("matching the client certificate"));
  printf (" %s\n", "--ca-cert=FILE");
  printf ("   %s\n", _("CA certificate file to verify peer against"));
  printf (" %s\n", "-D, --verify-cert");
  printf ("   %s\n", _("Verify the peer's SSL certificate and hostname"));
#endif

  printf (" %s\n", "-e, --expect=STRING");
  printf ("    %s\n", _("Comma-delimited list of strings, at least one of them is expected in"));
  printf ("    %s", _("the first (status) line of the server response (default: "));
  printf ("%s)\n", HTTP_EXPECT);
  printf ("    %s\n", _("If specified skips all other status line logic (ex: 3xx, 4xx, 5xx processing)"));
  printf (" %s\n", "-d, --header-string=STRING");
  printf ("    %s\n", _("String to expect in the response headers"));
  printf (" %s\n", "-s, --string=STRING");
  printf ("    %s\n", _("String to expect in the content"));
  printf (" %s\n", "-u, --url=PATH");
  printf ("    %s\n", _("URL to GET or POST (default: /)"));
  printf (" %s\n", "-P, --post=STRING");
  printf ("    %s\n", _("URL encoded http POST data"));
  printf (" %s\n", "-j, --method=STRING  (for example: HEAD, OPTIONS, TRACE, PUT, DELETE, CONNECT)");
  printf ("    %s\n", _("Set HTTP method."));
  printf (" %s\n", "-N, --no-body");
  printf ("    %s\n", _("Don't wait for document body: stop reading after headers."));
  printf ("    %s\n", _("(Note that this still does an HTTP GET or POST, not a HEAD.)"));
  printf (" %s\n", "-M, --max-age=SECONDS");
  printf ("    %s\n", _("Warn if document is more than SECONDS old. the number can also be of"));
  printf ("    %s\n", _("the form \"10m\" for minutes, \"10h\" for hours, or \"10d\" for days."));
  printf (" %s\n", "-T, --content-type=STRING");
  printf ("    %s\n", _("specify Content-Type header media type when POSTing\n"));
  printf (" %s\n", "-l, --linespan");
  printf ("    %s\n", _("Allow regex to span newlines (must precede -r or -R)"));
  printf (" %s\n", "-r, --regex, --ereg=STRING");
  printf ("    %s\n", _("Search page for regex STRING"));
  printf (" %s\n", "-R, --eregi=STRING");
  printf ("    %s\n", _("Search page for case-insensitive regex STRING"));
  printf (" %s\n", "--invert-regex");
  printf ("    %s\n", _("Return CRITICAL if found, OK if not\n"));
  printf (" %s\n", "-a, --authorization=AUTH_PAIR");
  printf ("    %s\n", _("Username:password on sites with basic authentication"));
  printf (" %s\n", "-b, --proxy-authorization=AUTH_PAIR");
  printf ("    %s\n", _("Username:password on proxy-servers with basic authentication"));
  printf (" %s\n", "-A, --useragent=STRING");
  printf ("    %s\n", _("String to be sent in http header as \"User Agent\""));
  printf (" %s\n", "-k, --header=STRING");
  printf ("    %s\n", _("Any other tags to be sent in http header. Use multiple times for additional headers"));
  printf (" %s\n", "-E, --extended-perfdata");
  printf ("    %s\n", _("Print additional performance data"));
  printf (" %s\n", "-B, --show-body");
  printf ("    %s\n", _("Print body content below status line"));
  printf (" %s\n", "-L, --link");
  printf ("    %s\n", _("Wrap output in HTML link (obsoleted by urlize)"));
  printf (" %s\n", "-f, --onredirect=<ok|warning|critical|follow|sticky|stickyport|curl>");
  printf ("    %s\n", _("How to handle redirected pages. sticky is like follow but stick to the"));
  printf ("    %s\n", _("specified IP address. stickyport also ensures port stays the same."));
  printf ("    %s\n", _("follow uses the old redirection algorithm of check_http."));
  printf ("    %s\n", _("curl uses CURL_FOLLOWLOCATION built into libcurl."));
  printf (" %s\n", "--max-redirs=INTEGER");
  printf ("    %s", _("Maximal number of redirects (default: "));
  printf ("%d)\n", DEFAULT_MAX_REDIRS);
  printf (" %s\n", "-m, --pagesize=INTEGER<:INTEGER>");
  printf ("    %s\n", _("Minimum page size required (bytes) : Maximum page size required (bytes)"));
  printf ("\n");
  printf (" %s\n", "--http-version=VERSION");
  printf ("    %s\n", _("Connect via specific HTTP protocol."));
  printf ("    %s\n", _("1.0 = HTTP/1.0, 1.1 = HTTP/1.1, 2.0 = HTTP/2 (HTTP/2 will fail without -S)"));
  printf (" %s\n", "--enable-automatic-decompression");
  printf ("    %s\n", _("Enable automatic decompression of body (CURLOPT_ACCEPT_ENCODING)."));
  printf ("\n");

  printf (UT_WARN_CRIT);

  printf (UT_CONN_TIMEOUT, DEFAULT_SOCKET_TIMEOUT);

  printf (UT_VERBOSE);

  printf ("\n");
  printf ("%s\n", _("Notes:"));
  printf (" %s\n", _("This plugin will attempt to open an HTTP connection with the host."));
  printf (" %s\n", _("Successful connects return STATE_OK, refusals and timeouts return STATE_CRITICAL"));
  printf (" %s\n", _("other errors return STATE_UNKNOWN.  Successful connects, but incorrect response"));
  printf (" %s\n", _("messages from the host result in STATE_WARNING return values.  If you are"));
  printf (" %s\n", _("checking a virtual server that uses 'host headers' you must supply the FQDN"));
  printf (" %s\n", _("(fully qualified domain name) as the [host_name] argument."));

#ifdef LIBCURL_FEATURE_SSL
  printf ("\n");
  printf (" %s\n", _("This plugin can also check whether an SSL enabled web server is able to"));
  printf (" %s\n", _("serve content (optionally within a specified time) or whether the X509 "));
  printf (" %s\n", _("certificate is still valid for the specified number of days."));
  printf ("\n");
  printf (" %s\n", _("Please note that this plugin does not check if the presented server"));
  printf (" %s\n", _("certificate matches the hostname of the server, or if the certificate"));
  printf (" %s\n", _("has a valid chain of trust to one of the locally installed CAs."));
  printf ("\n");
  printf ("%s\n", _("Examples:"));
  printf (" %s\n\n", "CHECK CONTENT: check_curl -w 5 -c 10 --ssl -H www.verisign.com");
  printf (" %s\n", _("When the 'www.verisign.com' server returns its content within 5 seconds,"));
  printf (" %s\n", _("a STATE_OK will be returned. When the server returns its content but exceeds"));
  printf (" %s\n", _("the 5-second threshold, a STATE_WARNING will be returned. When an error occurs,"));
  printf (" %s\n", _("a STATE_CRITICAL will be returned."));
  printf ("\n");
  printf (" %s\n\n", "CHECK CERTIFICATE: check_curl -H www.verisign.com -C 14");
  printf (" %s\n", _("When the certificate of 'www.verisign.com' is valid for more than 14 days,"));
  printf (" %s\n", _("a STATE_OK is returned. When the certificate is still valid, but for less than"));
  printf (" %s\n", _("14 days, a STATE_WARNING is returned. A STATE_CRITICAL will be returned when"));
  printf (" %s\n\n", _("the certificate is expired."));
  printf ("\n");
  printf (" %s\n\n", "CHECK CERTIFICATE: check_curl -H www.verisign.com -C 30,14");
  printf (" %s\n", _("When the certificate of 'www.verisign.com' is valid for more than 30 days,"));
  printf (" %s\n", _("a STATE_OK is returned. When the certificate is still valid, but for less than"));
  printf (" %s\n", _("30 days, but more than 14 days, a STATE_WARNING is returned."));
  printf (" %s\n", _("A STATE_CRITICAL will be returned when certificate expires in less than 14 days"));
#endif

  printf ("\n %s\n", "CHECK WEBSERVER CONTENT VIA PROXY:");
  printf (" %s\n", _("It is recommended to use an environment proxy like:"));
  printf (" %s\n", _("http_proxy=http://192.168.100.35:3128 ./check_curl -H www.monitoring-plugins.org"));
  printf (" %s\n", _("legacy proxy requests in check_http style still work:"));
  printf (" %s\n", _("check_curl -I 192.168.100.35 -p 3128 -u http://www.monitoring-plugins.org/ -H www.monitoring-plugins.org"));

#ifdef LIBCURL_FEATURE_SSL
  printf ("\n %s\n", "CHECK SSL WEBSERVER CONTENT VIA PROXY USING HTTP 1.1 CONNECT: ");
  printf (" %s\n", _("It is recommended to use an environment proxy like:"));
  printf (" %s\n", _("https_proxy=http://192.168.100.35:3128 ./check_curl -H www.verisign.com -S"));
  printf (" %s\n", _("legacy proxy requests in check_http style still work:"));
  printf (" %s\n", _("check_curl -I 192.168.100.35 -p 3128 -u https://www.verisign.com/ -S -j CONNECT -H www.verisign.com "));
  printf (" %s\n", _("all these options are needed: -I <proxy> -p <proxy-port> -u <check-url> -S(sl) -j CONNECT -H <webserver>"));
  printf (" %s\n", _("a STATE_OK will be returned. When the server returns its content but exceeds"));
  printf (" %s\n", _("the 5-second threshold, a STATE_WARNING will be returned. When an error occurs,"));
  printf (" %s\n", _("a STATE_CRITICAL will be returned."));

#endif

  printf (UT_SUPPORT);

}



void
print_usage (void)
{
  printf ("%s\n", _("Usage:"));
  printf (" %s -H <vhost> | -I <IP-address> [-u <uri>] [-p <port>]\n",progname);
  printf ("       [-J <client certificate file>] [-K <private key>] [--ca-cert <CA certificate file>] [-D]\n");
  printf ("       [-w <warn time>] [-c <critical time>] [-t <timeout>] [-L] [-E] [-a auth]\n");
  printf ("       [-b proxy_auth] [-f <ok|warning|critcal|follow|sticky|stickyport|curl>]\n");
  printf ("       [-e <expect>] [-d string] [-s string] [-l] [-r <regex> | -R <case-insensitive regex>]\n");
  printf ("       [-P string] [-m <min_pg_size>:<max_pg_size>] [-4|-6] [-N] [-M <age>]\n");
  printf ("       [-A string] [-k string] [-S <version>] [--sni]\n");
  printf ("       [-T <content-type>] [-j method]\n");
  printf ("       [--http-version=<version>]\n");
  printf (" %s -H <vhost> | -I <IP-address> -C <warn_age>[,<crit_age>]\n",progname);
  printf ("       [-p <port>] [-t <timeout>] [-4|-6] [--sni]\n");
  printf ("\n");
#ifdef LIBCURL_FEATURE_SSL
  printf ("%s\n", _("In the first form, make an HTTP request."));
  printf ("%s\n\n", _("In the second form, connect to the server and check the TLS certificate."));
#endif
  printf ("%s\n", _("WARNING: check_curl is experimental. Please use"));
  printf ("%s\n\n", _("check_http if you need a stable version."));
}

void
print_curl_version (void)
{
  printf( "%s\n", curl_version());
}

int
curlhelp_initwritebuffer (curlhelp_write_curlbuf *buf)
{
  buf->bufsize = DEFAULT_BUFFER_SIZE;
  buf->buflen = 0;
  buf->buf = (char *)malloc ((size_t)buf->bufsize);
  if (buf->buf == NULL) return -1;
  return 0;
}

int
curlhelp_buffer_write_callback (void *buffer, size_t size, size_t nmemb, void *stream)
{
  curlhelp_write_curlbuf *buf = (curlhelp_write_curlbuf *)stream;

  while (buf->bufsize < buf->buflen + size * nmemb + 1) {
    buf->bufsize *= buf->bufsize * 2;
    buf->buf = (char *)realloc (buf->buf, buf->bufsize);
    if (buf->buf == NULL) return -1;
  }

  memcpy (buf->buf + buf->buflen, buffer, size * nmemb);
  buf->buflen += size * nmemb;
  buf->buf[buf->buflen] = '\0';

  return (int)(size * nmemb);
}

int
curlhelp_buffer_read_callback (void *buffer, size_t size, size_t nmemb, void *stream)
{
  curlhelp_read_curlbuf *buf = (curlhelp_read_curlbuf *)stream;

  size_t n = min (nmemb * size, buf->buflen - buf->pos);

  memcpy (buffer, buf->buf + buf->pos, n);
  buf->pos += n;

  return (int)n;
}

void
curlhelp_freewritebuffer (curlhelp_write_curlbuf *buf)
{
  free (buf->buf);
  buf->buf = NULL;
}

int
curlhelp_initreadbuffer (curlhelp_read_curlbuf *buf, const char *data, size_t datalen)
{
  buf->buflen = datalen;
  buf->buf = (char *)malloc ((size_t)buf->buflen);
  if (buf->buf == NULL) return -1;
  memcpy (buf->buf, data, datalen);
  buf->pos = 0;
  return 0;
}

void
curlhelp_freereadbuffer (curlhelp_read_curlbuf *buf)
{
  free (buf->buf);
  buf->buf = NULL;
}

/* TODO: where to put this, it's actually part of sstrings2 (logically)?
 */
const char*
strrstr2(const char *haystack, const char *needle)
{
  int counter;
  size_t len;
  const char *prev_pos;
  const char *pos;

  if (haystack == NULL || needle == NULL)
    return NULL;

  if (haystack[0] == '\0' || needle[0] == '\0')
    return NULL;

  counter = 0;
  prev_pos = NULL;
  pos = haystack;
  len = strlen (needle);
  for (;;) {
    pos = strstr (pos, needle);
    if (pos == NULL) {
      if (counter == 0)
        return NULL;
      else
        return prev_pos;
    }
    counter++;
    prev_pos = pos;
    pos += len;
    if (*pos == '\0') return prev_pos;
  }
}

int
curlhelp_parse_statusline (const char *buf, curlhelp_statusline *status_line)
{
  char *first_line_end;
  char *p;
  size_t first_line_len;
  char *pp;
  const char *start;
  char *first_line_buf;

  /* find last start of a new header */
  start = strrstr2 (buf, "\r\nHTTP/");
  if (start != NULL) {
    start += 2;
    buf = start;
  }

  first_line_end = strstr(buf, "\r\n");
  if (first_line_end == NULL) return -1;

  first_line_len = (size_t)(first_line_end - buf);
  status_line->first_line = (char *)malloc (first_line_len + 1);
  if (status_line->first_line == NULL) return -1;
  memcpy (status_line->first_line, buf, first_line_len);
  status_line->first_line[first_line_len] = '\0';
  first_line_buf = strdup( status_line->first_line );

  /* protocol and version: "HTTP/x.x" SP or "HTTP/2" SP */

  p = strtok(first_line_buf, "/");
  if( p == NULL ) { free( first_line_buf ); return -1; }
  if( strcmp( p, "HTTP" ) != 0 ) { free( first_line_buf ); return -1; }

  p = strtok( NULL, " " );
  if( p == NULL ) { free( first_line_buf ); return -1; }
  if( strchr( p, '.' ) != NULL ) {

    /* HTTP 1.x case */
    char *ppp;
    ppp = strtok( p, "." );
    status_line->http_major = (int)strtol( p, &pp, 10 );
    if( *pp != '\0' ) { free( first_line_buf ); return -1; }
    ppp = strtok( NULL, " " );
    status_line->http_minor = (int)strtol( p, &pp, 10 );
    if( *pp != '\0' ) { free( first_line_buf ); return -1; }
    p += 4; /* 1.x SP */
  } else {
    /* HTTP 2 case */
    status_line->http_major = (int)strtol( p, &pp, 10 );
    status_line->http_minor = 0;
    p += 2; /* 2 SP */
  }

  /* status code: "404" or "404.1", then SP */

  p = strtok( p, " " );
  if( p == NULL ) { free( first_line_buf ); return -1; }
  if( strchr( p, '.' ) != NULL ) {
    char *ppp;
    ppp = strtok( p, "." );
    status_line->http_code = (int)strtol( ppp, &pp, 10 );
    if( *pp != '\0' ) { free( first_line_buf ); return -1; }
    ppp = strtok( NULL, "" );
    status_line->http_subcode = (int)strtol( ppp, &pp, 10 );
    if( *pp != '\0' ) { free( first_line_buf ); return -1; }
    p += 6; /* 400.1 SP */
  } else {
    status_line->http_code = (int)strtol( p, &pp, 10 );
    status_line->http_subcode = -1;
    if( *pp != '\0' ) { free( first_line_buf ); return -1; }
    p += 4; /* 400 SP */
  }

  /* Human readable message: "Not Found" CRLF */

  p = strtok( p, "" );
  if( p == NULL ) { status_line->msg = ""; return 0; }
  status_line->msg = status_line->first_line + ( p - first_line_buf );
  free( first_line_buf );

  return 0;
}

void
curlhelp_free_statusline (curlhelp_statusline *status_line)
{
  free (status_line->first_line);
}

void
remove_newlines (char *s)
{
  char *p;

  for (p = s; *p != '\0'; p++)
    if (*p == '\r' || *p == '\n')
      *p = ' ';
}

char *
get_header_value (const struct phr_header* headers, const size_t nof_headers, const char* header)
{
  int i;
  for( i = 0; i < nof_headers; i++ ) {
    if(headers[i].name != NULL && strncasecmp( header, headers[i].name, max( headers[i].name_len, 4 ) ) == 0 ) {
      return strndup( headers[i].value, headers[i].value_len );
    }
  }
  return NULL;
}

int
check_document_dates (const curlhelp_write_curlbuf *header_buf, char (*msg)[DEFAULT_BUFFER_SIZE])
{
  char *server_date = NULL;
  char *document_date = NULL;
  int date_result = STATE_OK;
  curlhelp_statusline status_line;
  struct phr_header headers[255];
  size_t nof_headers = 255;
  size_t msglen;

  int res = phr_parse_response (header_buf->buf, header_buf->buflen,
    &status_line.http_major, &status_line.http_minor, &status_line.http_code, &status_line.msg, &msglen,
    headers, &nof_headers, 0);

  server_date = get_header_value (headers, nof_headers, "date");
  document_date = get_header_value (headers, nof_headers, "last-modified");

  if (!server_date || !*server_date) {
    snprintf (*msg, DEFAULT_BUFFER_SIZE, _("%sServer date unknown, "), *msg);
    date_result = max_state_alt(STATE_UNKNOWN, date_result);
  } else if (!document_date || !*document_date) {
    snprintf (*msg, DEFAULT_BUFFER_SIZE, _("%sDocument modification date unknown, "), *msg);
    date_result = max_state_alt(STATE_CRITICAL, date_result);
  } else {
    time_t srv_data = curl_getdate (server_date, NULL);
    time_t doc_data = curl_getdate (document_date, NULL);
    if (verbose >= 2)
      printf ("* server date: '%s' (%d), doc_date: '%s' (%d)\n", server_date, (int)srv_data, document_date, (int)doc_data);
    if (srv_data <= 0) {
      snprintf (*msg, DEFAULT_BUFFER_SIZE, _("%sServer date \"%100s\" unparsable, "), *msg, server_date);
      date_result = max_state_alt(STATE_CRITICAL, date_result);
    } else if (doc_data <= 0) {
      snprintf (*msg, DEFAULT_BUFFER_SIZE, _("%sDocument date \"%100s\" unparsable, "), *msg, document_date);
      date_result = max_state_alt(STATE_CRITICAL, date_result);
    } else if (doc_data > srv_data + 30) {
      snprintf (*msg, DEFAULT_BUFFER_SIZE, _("%sDocument is %d seconds in the future, "), *msg, (int)doc_data - (int)srv_data);
      date_result = max_state_alt(STATE_CRITICAL, date_result);
    } else if (doc_data < srv_data - maximum_age) {
      int n = (srv_data - doc_data);
      if (n > (60 * 60 * 24 * 2)) {
        snprintf (*msg, DEFAULT_BUFFER_SIZE, _("%sLast modified %.1f days ago, "), *msg, ((float) n) / (60 * 60 * 24));
        date_result = max_state_alt(STATE_CRITICAL, date_result);
      } else {
        snprintf (*msg, DEFAULT_BUFFER_SIZE, _("%sLast modified %d:%02d:%02d ago, "), *msg, n / (60 * 60), (n / 60) % 60, n % 60);
        date_result = max_state_alt(STATE_CRITICAL, date_result);
      }
    }
  }

  if (server_date) free (server_date);
  if (document_date) free (document_date);

  return date_result;
}


int
get_content_length (const curlhelp_write_curlbuf* header_buf, const curlhelp_write_curlbuf* body_buf)
{
  const char *s;
  int content_length = 0;
  char *copy;
  struct phr_header headers[255];
  size_t nof_headers = 255;
  size_t msglen;
  char *content_length_s = NULL;
  curlhelp_statusline status_line;

  int res = phr_parse_response (header_buf->buf, header_buf->buflen,
    &status_line.http_major, &status_line.http_minor, &status_line.http_code, &status_line.msg, &msglen,
    headers, &nof_headers, 0);

  content_length_s = get_header_value (headers, nof_headers, "content-length");
  if (!content_length_s) {
    return header_buf->buflen + body_buf->buflen;
  }
  content_length_s += strspn (content_length_s, " \t");
  content_length = atoi (content_length_s);
  if (content_length != body_buf->buflen) {
    /* TODO: should we warn if the actual and the reported body length don't match? */
  }

  if (content_length_s) free (content_length_s);

  return header_buf->buflen + body_buf->buflen;
}

/* TODO: is there a better way in libcurl to check for the SSL library? */
curlhelp_ssl_library
curlhelp_get_ssl_library (CURL* curl)
{
  curl_version_info_data* version_data;
  char *ssl_version;
  char *library;
  curlhelp_ssl_library ssl_library = CURLHELP_SSL_LIBRARY_UNKNOWN;

  version_data = curl_version_info (CURLVERSION_NOW);
  if (version_data == NULL) return CURLHELP_SSL_LIBRARY_UNKNOWN;

  ssl_version = strdup (version_data->ssl_version);
  if (ssl_version == NULL ) return CURLHELP_SSL_LIBRARY_UNKNOWN;

  library = strtok (ssl_version, "/");
  if (library == NULL) return CURLHELP_SSL_LIBRARY_UNKNOWN;

  if (strcmp (library, "OpenSSL") == 0)
    ssl_library = CURLHELP_SSL_LIBRARY_OPENSSL;
  else if (strcmp (library, "LibreSSL") == 0)
    ssl_library = CURLHELP_SSL_LIBRARY_LIBRESSL;
  else if (strcmp (library, "GnuTLS") == 0)
    ssl_library = CURLHELP_SSL_LIBRARY_GNUTLS;
  else if (strcmp (library, "NSS") == 0)
    ssl_library = CURLHELP_SSL_LIBRARY_NSS;

  if (verbose >= 2)
    printf ("* SSL library string is : %s %s (%d)\n", version_data->ssl_version, library, ssl_library);

  free (ssl_version);

  return ssl_library;
}

const char*
curlhelp_get_ssl_library_string (curlhelp_ssl_library ssl_library)
{
  switch (ssl_library) {
    case CURLHELP_SSL_LIBRARY_OPENSSL:
      return "OpenSSL";
    case CURLHELP_SSL_LIBRARY_LIBRESSL:
      return "LibreSSL";
    case CURLHELP_SSL_LIBRARY_GNUTLS:
      return "GnuTLS";
    case CURLHELP_SSL_LIBRARY_NSS:
      return "NSS";
    case CURLHELP_SSL_LIBRARY_UNKNOWN:
    default:
      return "unknown";
  }
}

#ifdef LIBCURL_FEATURE_SSL
#ifndef USE_OPENSSL
time_t
parse_cert_date (const char *s)
{
  struct tm tm;
  time_t date;
  char *res;

  if (!s) return -1;

  /* Jan 17 14:25:12 2020 GMT */
  res = strptime (s, "%Y-%m-%d %H:%M:%S GMT", &tm);
  /* Sep 11 12:00:00 2020 GMT */
  if (res == NULL) strptime (s, "%Y %m %d %H:%M:%S GMT", &tm);
  date = mktime (&tm);

  return date;
}

/* TODO: this needs cleanup in the sslutils.c, maybe we the #else case to
 * OpenSSL could be this function
 */
int
net_noopenssl_check_certificate (cert_ptr_union* cert_ptr, int days_till_exp_warn, int days_till_exp_crit)
{
  int i;
  struct curl_slist* slist;
  int cname_found = 0;
  char* start_date_str = NULL;
  char* end_date_str = NULL;
  time_t start_date;
  time_t end_date;
	char *tz;
	float time_left;
	int days_left;
	int time_remaining;
	char timestamp[50] = "";
	int status = STATE_UNKNOWN;

  if (verbose >= 2)
    printf ("**** REQUEST CERTIFICATES ****\n");

  for (i = 0; i < cert_ptr->to_certinfo->num_of_certs; i++) {
    for (slist = cert_ptr->to_certinfo->certinfo[i]; slist; slist = slist->next) {
      /* find first common name in subject,
       * TODO: check alternative subjects for
       * TODO: have a decent parser here and not a hack
       * multi-host certificate, check wildcards
       */
      if (strncasecmp (slist->data, "Subject:", 8) == 0) {
        int d = 3;
        char* p = strstr (slist->data, "CN=");
        if (p == NULL) {
          d = 5;
          p = strstr (slist->data, "CN = ");
        }
        if (p != NULL) {
          if (strncmp (host_name, p+d, strlen (host_name)) == 0) {
            cname_found = 1;
          }
        }
      } else if (strncasecmp (slist->data, "Start Date:", 11) == 0) {
        start_date_str = &slist->data[11];
      } else if (strncasecmp (slist->data, "Expire Date:", 12) == 0) {
        end_date_str = &slist->data[12];
      } else if (strncasecmp (slist->data, "Cert:", 5) == 0) {
        goto HAVE_FIRST_CERT;
      }
      if (verbose >= 2)
        printf ("%d ** %s\n", i, slist->data);
    }
  }
HAVE_FIRST_CERT:

  if (verbose >= 2)
    printf ("**** REQUEST CERTIFICATES ****\n");

  if (!cname_found) {
		printf("%s\n",_("CRITICAL - Cannot retrieve certificate subject."));
		return STATE_CRITICAL;
  }

  start_date = parse_cert_date (start_date_str);
  if (start_date <= 0) {
    snprintf (msg, DEFAULT_BUFFER_SIZE, _("WARNING - Unparsable 'Start Date' in certificate: '%s'"),
      start_date_str);
    puts (msg);
    return STATE_WARNING;
  }

  end_date = parse_cert_date (end_date_str);
  if (end_date <= 0) {
    snprintf (msg, DEFAULT_BUFFER_SIZE, _("WARNING - Unparsable 'Expire Date' in certificate: '%s'"),
      start_date_str);
    puts (msg);
    return STATE_WARNING;
  }

  time_left = difftime (end_date, time(NULL));
	days_left = time_left / 86400;
	tz = getenv("TZ");
	setenv("TZ", "GMT", 1);
	tzset();
	strftime(timestamp, 50, "%c %z", localtime(&end_date));
	if (tz)
		setenv("TZ", tz, 1);
	else
		unsetenv("TZ");
	tzset();

	if (days_left > 0 && days_left <= days_till_exp_warn) {
		printf (_("%s - Certificate '%s' expires in %d day(s) (%s).\n"), (days_left>days_till_exp_crit)?"WARNING":"CRITICAL", host_name, days_left, timestamp);
		if (days_left > days_till_exp_crit)
			status = STATE_WARNING;
		else
			status = STATE_CRITICAL;
	} else if (days_left == 0 && time_left > 0) {
		if (time_left >= 3600)
			time_remaining = (int) time_left / 3600;
		else
			time_remaining = (int) time_left / 60;

		printf (_("%s - Certificate '%s' expires in %u %s (%s)\n"),
			(days_left>days_till_exp_crit) ? "WARNING" : "CRITICAL", host_name, time_remaining,
			time_left >= 3600 ? "hours" : "minutes", timestamp);

		if ( days_left > days_till_exp_crit)
			status = STATE_WARNING;
		else
			status = STATE_CRITICAL;
	} else if (time_left < 0) {
		printf(_("CRITICAL - Certificate '%s' expired on %s.\n"), host_name, timestamp);
		status=STATE_CRITICAL;
	} else if (days_left == 0) {
		printf (_("%s - Certificate '%s' just expired (%s).\n"), (days_left>days_till_exp_crit)?"WARNING":"CRITICAL", host_name, timestamp);
		if (days_left > days_till_exp_crit)
			status = STATE_WARNING;
		else
			status = STATE_CRITICAL;
	} else {
		printf(_("OK - Certificate '%s' will expire on %s.\n"), host_name, timestamp);
		status = STATE_OK;
	}
	return status;
}
#endif /* USE_OPENSSL */
#endif /* LIBCURL_FEATURE_SSL */