/*
     This file is part of libmicrohttpd
     Copyright (C) 2007, 2008 Christian Grothoff (and other contributing authors)
     Copyright (C) 2016-2022 Evgeny Grin (Karlson2k)

     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Lesser General Public
     License as published by the Free Software Foundation; either
     version 2.1 of the License, or (at your option) any later version.

     This library 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
     Lesser General Public License for more details.

     You should have received a copy of the GNU Lesser General Public
     License along with this library; if not, write to the Free Software
     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*/
/**
 * @file https_fileserver_example.c
 * @brief a simple HTTPS file server using TLS.
 *
 * Usage :
 *
 *  'http_fileserver_example HTTP-PORT SECONDS-TO-RUN'
 *
 * The certificate & key are required by the server to operate, omitting the
 * path arguments will cause the server to use the hard coded example certificate & key.
 *
 * 'certtool' may be used to generate these if required.
 *
 * @author Sagie Amir
 * @author Karlson2k (Evgeny Grin)
 */

#include "platform.h"
#include <microhttpd.h>
#include <sys/stat.h>

#define BUF_SIZE 1024
#define MAX_URL_LEN 255

#define EMPTY_PAGE \
  "<html><head><title>File not found</title></head><body>File not found</body></html>"

/* test server key */
static const char key_pem[] =
  "-----BEGIN PRIVATE KEY-----\n\
MIIEvgIBADANBgkqhkiG9w0BAQEFAASCBKgwggSkAgEAAoIBAQCff7amw9zNSE+h\n\
rOMhBrzbbsJluUP3gmd8nOKY5MUimoPkxmAXfp2L0il+MPZT/ZEmo11q0k6J2jfG\n\
UBQ+oZW9ahNZ9gCDjbYlBblo/mqTai+LdeLO3qk53d0zrZKXvCO6sA3uKpG2WR+g\n\
+sNKxfYpIHCpanqBU6O+degIV/+WKy3nQ2Fwp7K5HUNj1u0pg0QQ18yf68LTnKFU\n\
HFjZmmaaopWki5wKSBieHivzQy6w+04HSTogHHRK/y/UcoJNSG7xnHmoPPo1vLT8\n\
CMRIYnSSgU3wJ43XBJ80WxrC2dcoZjV2XZz+XdQwCD4ZrC1ihykcAmiQA+sauNm7\n\
dztOMkGzAgMBAAECggEAIbKDzlvXDG/YkxnJqrKXt+yAmak4mNQuNP+YSCEdHSBz\n\
+SOILa6MbnvqVETX5grOXdFp7SWdfjZiTj2g6VKOJkSA7iKxHRoVf2DkOTB3J8np\n\
XZd8YaRdMGKVV1O2guQ20Dxd1RGdU18k9YfFNsj4Jtw5sTFTzHr1P0n9ybV9xCXp\n\
znSxVfRg8U6TcMHoRDJR9EMKQMO4W3OQEmreEPoGt2/+kMuiHjclxLtbwDxKXTLP\n\
pD0gdg3ibvlufk/ccKl/yAglDmd0dfW22oS7NgvRKUve7tzDxY1Q6O5v8BCnLFSW\n\
D+z4hS1PzooYRXRkM0xYudvPkryPyu+1kEpw3fNsoQKBgQDRfXJo82XQvlX8WPdZ\n\
Ts3PfBKKMVu3Wf8J3SYpuvYT816qR3ot6e4Ivv5ZCQkdDwzzBKe2jAv6JddMJIhx\n\
pkGHc0KKOodd9HoBewOd8Td++hapJAGaGblhL5beIidLKjXDjLqtgoHRGlv5Cojo\n\
zHa7Viel1eOPPcBumhp83oJ+mQKBgQDC6PmdETZdrW3QPm7ZXxRzF1vvpC55wmPg\n\
pRfTRM059jzRzAk0QiBgVp3yk2a6Ob3mB2MLfQVDgzGf37h2oO07s5nspSFZTFnM\n\
KgSjFy0xVOAVDLe+0VpbmLp1YUTYvdCNowaoTE7++5rpePUDu3BjAifx07/yaSB+\n\
W+YPOfOuKwKBgQCGK6g5G5qcJSuBIaHZ6yTZvIdLRu2M8vDral5k3793a6m3uWvB\n\
OFAh/eF9ONJDcD5E7zhTLEMHhXDs7YEN+QODMwjs6yuDu27gv97DK5j1lEsrLUpx\n\
XgRjAE3KG2m7NF+WzO1K74khWZaKXHrvTvTEaxudlO3X8h7rN3u7ee9uEQKBgQC2\n\
wI1zeTUZhsiFTlTPWfgppchdHPs6zUqq0wFQ5Zzr8Pa72+zxY+NJkU2NqinTCNsG\n\
ePykQ/gQgk2gUrt595AYv2De40IuoYk9BlTMuql0LNniwsbykwd/BOgnsSlFdEy8\n\
0RQn70zOhgmNSg2qDzDklJvxghLi7zE5aV9//V1/ewKBgFRHHZN1a8q/v8AAOeoB\n\
ROuXfgDDpxNNUKbzLL5MO5odgZGi61PBZlxffrSOqyZoJkzawXycNtoBP47tcVzT\n\
QPq5ZOB3kjHTcN7dRLmPWjji9h4O3eHCX67XaPVMSWiMuNtOZIg2an06+jxGFhLE\n\
qdJNJ1DkyUc9dN2cliX4R+rG\n\
-----END PRIVATE KEY-----";

/* test server CA signed certificates */
static const char cert_pem[] =
  "-----BEGIN CERTIFICATE-----\n\
MIIFSzCCAzOgAwIBAgIBBDANBgkqhkiG9w0BAQsFADCBgTELMAkGA1UEBhMCUlUx\n\
DzANBgNVBAgMBk1vc2NvdzEPMA0GA1UEBwwGTW9zY293MRswGQYDVQQKDBJ0ZXN0\n\
LWxpYm1pY3JvaHR0cGQxITAfBgkqhkiG9w0BCQEWEm5vYm9keUBleGFtcGxlLm9y\n\
ZzEQMA4GA1UEAwwHdGVzdC1DQTAgFw0yMjA0MjAxODQzMDJaGA8yMTIyMDMyNjE4\n\
NDMwMlowZTELMAkGA1UEBhMCUlUxDzANBgNVBAgMBk1vc2NvdzEPMA0GA1UEBwwG\n\
TW9zY293MRswGQYDVQQKDBJ0ZXN0LWxpYm1pY3JvaHR0cGQxFzAVBgNVBAMMDnRl\n\
c3QtbWhkc2VydmVyMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAn3+2\n\
psPczUhPoazjIQa8227CZblD94JnfJzimOTFIpqD5MZgF36di9IpfjD2U/2RJqNd\n\
atJOido3xlAUPqGVvWoTWfYAg422JQW5aP5qk2ovi3Xizt6pOd3dM62Sl7wjurAN\n\
7iqRtlkfoPrDSsX2KSBwqWp6gVOjvnXoCFf/list50NhcKeyuR1DY9btKYNEENfM\n\
n+vC05yhVBxY2ZpmmqKVpIucCkgYnh4r80MusPtOB0k6IBx0Sv8v1HKCTUhu8Zx5\n\
qDz6Nby0/AjESGJ0koFN8CeN1wSfNFsawtnXKGY1dl2c/l3UMAg+GawtYocpHAJo\n\
kAPrGrjZu3c7TjJBswIDAQABo4HmMIHjMAsGA1UdDwQEAwIFoDAMBgNVHRMBAf8E\n\
AjAAMBYGA1UdJQEB/wQMMAoGCCsGAQUFBwMBMDEGA1UdEQQqMCiCDnRlc3QtbWhk\n\
c2VydmVyhwR/AAABhxAAAAAAAAAAAAAAAAAAAAABMB0GA1UdDgQWBBQ57Z06WJae\n\
8fJIHId4QGx/HsRgDDAoBglghkgBhvhCAQ0EGxYZVGVzdCBsaWJtaWNyb2h0dHBk\n\
IHNlcnZlcjARBglghkgBhvhCAQEEBAMCBkAwHwYDVR0jBBgwFoAUWHVDwKVqMcOF\n\
Nd0arI3/QB3W6SwwDQYJKoZIhvcNAQELBQADggIBAI7Lggm/XzpugV93H5+KV48x\n\
X+Ct8unNmPCSzCaI5hAHGeBBJpvD0KME5oiJ5p2wfCtK5Dt9zzf0S0xYdRKqU8+N\n\
aKIvPoU1hFixXLwTte1qOp6TviGvA9Xn2Fc4n36dLt6e9aiqDnqPbJgBwcVO82ll\n\
HJxVr3WbrAcQTB3irFUMqgAke/Cva9Bw79VZgX4ghb5EnejDzuyup4pHGzV10Myv\n\
hdg+VWZbAxpCe0S4eKmstZC7mWsFCLeoRTf/9Pk1kQ6+azbTuV/9QOBNfFi8QNyb\n\
18jUjmm8sc2HKo8miCGqb2sFqaGD918hfkWmR+fFkzQ3DZQrT+eYbKq2un3k0pMy\n\
UySy8SRn1eadfab+GwBVb68I9TrPRMrJsIzysNXMX4iKYl2fFE/RSNnaHtPw0C8y\n\
B7memyxPRl+H2xg6UjpoKYh3+8e44/XKm0rNIzXjrwA8f8gnw2TbqmMDkj1YqGnC\n\
SCj5A27zUzaf2pT/YsnQXIWOJjVvbEI+YKj34wKWyTrXA093y8YI8T3mal7Kr9YM\n\
WiIyPts0/aVeziM0Gunglz+8Rj1VesL52FTurobqusPgM/AME82+qb/qnxuPaCKj\n\
OT1qAbIblaRuWqCsid8BzP7ZQiAnAWgMRSUg1gzDwSwRhrYQRRWAyn/Qipzec+27\n\
/w0gW9EVWzFhsFeGEssi\n\
-----END CERTIFICATE-----";

static ssize_t
file_reader (void *cls, uint64_t pos, char *buf, size_t max)
{
  FILE *file = (FILE *) cls;
  size_t bytes_read;

  /* 'fseek' may not support files larger 2GiB, depending on platform.
   * For production code, make sure that 'pos' has valid values, supported by
   * 'fseek', or use 'fseeko' or similar function. */
  if (0 != fseek (file, (long) pos, SEEK_SET))
    return MHD_CONTENT_READER_END_WITH_ERROR;
  bytes_read = fread (buf, 1, max, file);
  if (0 == bytes_read)
    return (0 != ferror (file)) ? MHD_CONTENT_READER_END_WITH_ERROR :
           MHD_CONTENT_READER_END_OF_STREAM;
  return (ssize_t) bytes_read;
}


static void
file_free_callback (void *cls)
{
  FILE *file = cls;
  fclose (file);
}


/* HTTP access handler call back */
static enum MHD_Result
http_ahc (void *cls,
          struct MHD_Connection *connection,
          const char *url,
          const char *method,
          const char *version,
          const char *upload_data,
          size_t *upload_data_size, void **req_cls)
{
  static int aptr;
  struct MHD_Response *response;
  enum MHD_Result ret;
  FILE *file;
  int fd;
  struct stat buf;
  (void) cls;               /* Unused. Silent compiler warning. */
  (void) version;           /* Unused. Silent compiler warning. */
  (void) upload_data;       /* Unused. Silent compiler warning. */
  (void) upload_data_size;  /* Unused. Silent compiler warning. */

  if (0 != strcmp (method, MHD_HTTP_METHOD_GET))
    return MHD_NO;              /* unexpected method */
  if (&aptr != *req_cls)
  {
    /* do never respond on first call */
    *req_cls = &aptr;
    return MHD_YES;
  }
  *req_cls = NULL;                  /* reset when done */

  file = fopen (&url[1], "rb");
  if (NULL != file)
  {
    fd = fileno (file);
    if (-1 == fd)
    {
      (void) fclose (file);
      return MHD_NO;     /* internal error */
    }
    if ( (0 != fstat (fd, &buf)) ||
         (! S_ISREG (buf.st_mode)) )
    {
      /* not a regular file, refuse to serve */
      fclose (file);
      file = NULL;
    }
  }

  if (NULL == file)
  {
    response =
      MHD_create_response_from_buffer_static (strlen (EMPTY_PAGE),
                                              (const void *) EMPTY_PAGE);
    ret = MHD_queue_response (connection, MHD_HTTP_NOT_FOUND, response);
    MHD_destroy_response (response);
  }
  else
  {
    response = MHD_create_response_from_callback ((size_t) buf.st_size,
                                                  32 * 1024,   /* 32k page size */
                                                  &file_reader, file,
                                                  &file_free_callback);
    if (NULL == response)
    {
      fclose (file);
      return MHD_NO;
    }
    ret = MHD_queue_response (connection, MHD_HTTP_OK, response);
    MHD_destroy_response (response);
  }
  return ret;
}


int
main (int argc, char *const *argv)
{
  struct MHD_Daemon *TLS_daemon;
  int port;

  if (argc != 2)
  {
    printf ("%s PORT\n", argv[0]);
    return 1;
  }
  port = atoi (argv[1]);
  if ( (1 > port) ||
       (port > UINT16_MAX) )
  {
    fprintf (stderr,
             "Port must be a number between 1 and 65535\n");
    return 1;
  }

  TLS_daemon =
    MHD_start_daemon (MHD_USE_THREAD_PER_CONNECTION
                      | MHD_USE_INTERNAL_POLLING_THREAD | MHD_USE_ERROR_LOG
                      | MHD_USE_TLS,
                      (uint16_t) port,
                      NULL, NULL,
                      &http_ahc, NULL,
                      MHD_OPTION_CONNECTION_TIMEOUT, 256,
                      MHD_OPTION_HTTPS_MEM_KEY, key_pem,
                      MHD_OPTION_HTTPS_MEM_CERT, cert_pem,
                      MHD_OPTION_END);
  if (NULL == TLS_daemon)
  {
    fprintf (stderr, "Error: failed to start TLS_daemon.\n");
    return 1;
  }
  printf ("MHD daemon listening on port %u\n",
          (unsigned int) port);

  (void) getc (stdin);

  MHD_stop_daemon (TLS_daemon);
  return 0;
}