mongoose.c

static void ns_add_to_set(sock_t sock, fd_set *set, sock_t *max_fd) {
  if (sock != INVALID_SOCKET) {
    FD_SET(sock, set);
    if (*max_fd == INVALID_SOCKET || sock > *max_fd) {
      *max_fd = sock;
    }
  }
}

time_t ns_mgr_poll(struct ns_mgr *mgr, int milli) {
  struct ns_connection *conn, *tmp_conn;
  struct timeval tv;
  fd_set read_set, write_set;
  sock_t max_fd = INVALID_SOCKET;
  time_t current_time = time(NULL);

  FD_ZERO(&read_set);
  FD_ZERO(&write_set);
  ns_add_to_set(mgr->ctl[1], &read_set, &max_fd);

  for (conn = mgr->active_connections; conn != NULL; conn = tmp_conn) {
    tmp_conn = conn->next;
    if (!(conn->flags & (NSF_LISTENING | NSF_CONNECTING))) {
      ns_call(conn, NS_POLL, &current_time);
    }
    if (!(conn->flags & NSF_WANT_WRITE)) {
      //DBG(("%p read_set", conn));
      ns_add_to_set(conn->sock, &read_set, &max_fd);
    }
    if (((conn->flags & NSF_CONNECTING) && !(conn->flags & NSF_WANT_READ)) ||
        (conn->send_iobuf.len > 0 && !(conn->flags & NSF_CONNECTING) &&
         !(conn->flags & NSF_BUFFER_BUT_DONT_SEND))) {
      //DBG(("%p write_set", conn));
      ns_add_to_set(conn->sock, &write_set, &max_fd);
    }
    if (conn->flags & NSF_CLOSE_IMMEDIATELY) {
      ns_close_conn(conn);
    }
  }

  tv.tv_sec = milli / 1000;
  tv.tv_usec = (milli % 1000) * 1000;

  if (select((int) max_fd + 1, &read_set, &write_set, NULL, &tv) > 0) {
    // select() might have been waiting for a long time, reset current_time
    // now to prevent last_io_time being set to the past.
    current_time = time(NULL);

    // Read wakeup messages
    if (mgr->ctl[1] != INVALID_SOCKET &&
        FD_ISSET(mgr->ctl[1], &read_set)) {
      struct ctl_msg ctl_msg;
      int len = (int) recv(mgr->ctl[1], (char *) &ctl_msg, sizeof(ctl_msg), 0);
      send(mgr->ctl[1], ctl_msg.message, 1, 0);
      if (len >= (int) sizeof(ctl_msg.callback) && ctl_msg.callback != NULL) {
        struct ns_connection *c;
        for (c = ns_next(mgr, NULL); c != NULL; c = ns_next(mgr, c)) {
          ctl_msg.callback(c, NS_POLL, ctl_msg.message);
        }
      }
    }

    for (conn = mgr->active_connections; conn != NULL; conn = tmp_conn) {
      tmp_conn = conn->next;
      if (FD_ISSET(conn->sock, &read_set)) {
        if (conn->flags & NSF_LISTENING) {
          if (conn->flags & NSF_UDP) {
            ns_handle_udp(conn);
          } else {
            // We're not looping here, and accepting just one connection at
            // a time. The reason is that eCos does not respect non-blocking
            // flag on a listening socket and hangs in a loop.
            accept_conn(conn);
          }
        } else {
          conn->last_io_time = current_time;
          ns_read_from_socket(conn);
        }
      }

      if (FD_ISSET(conn->sock, &write_set)) {
        if (conn->flags & NSF_CONNECTING) {
          ns_read_from_socket(conn);
        } else if (!(conn->flags & NSF_BUFFER_BUT_DONT_SEND)) {
          conn->last_io_time = current_time;
          ns_write_to_socket(conn);
        }
      }
    }
  }

  for (conn = mgr->active_connections; conn != NULL; conn = tmp_conn) {
    tmp_conn = conn->next;
    if ((conn->flags & NSF_CLOSE_IMMEDIATELY) ||
        (conn->send_iobuf.len == 0 &&
          (conn->flags & NSF_FINISHED_SENDING_DATA))) {
      ns_close_conn(conn);
    }
  }

  return current_time;
}

struct ns_connection *ns_connect(struct ns_mgr *mgr, const char *address,
                                 ns_callback_t callback, void *user_data) {
  sock_t sock = INVALID_SOCKET;
  struct ns_connection *nc = NULL;
  union socket_address sa;
  char cert[100], ca_cert[100];
  int rc, use_ssl, proto;

  ns_parse_address(address, &sa, &proto, &use_ssl, cert, ca_cert);
  if ((sock = socket(AF_INET, proto, 0)) == INVALID_SOCKET) {
    return NULL;
  }
  ns_set_non_blocking_mode(sock);
  rc = (proto == SOCK_DGRAM) ? 0 : connect(sock, &sa.sa, sizeof(sa.sin));

  if (rc != 0 && ns_is_error(rc)) {
    closesocket(sock);
    return NULL;
  } else if ((nc = ns_add_sock(mgr, sock, callback, user_data)) == NULL) {
    closesocket(sock);
    return NULL;
  }

  nc->sa = sa;   // Important, cause UDP conns will use sendto()
  nc->flags = (proto == SOCK_DGRAM) ? NSF_UDP : NSF_CONNECTING;

#ifdef NS_ENABLE_SSL
  if (use_ssl) {
    if ((nc->ssl_ctx = SSL_CTX_new(SSLv23_client_method())) == NULL ||
        ns_use_cert(nc->ssl_ctx, cert) != 0 ||
        ns_use_ca_cert(nc->ssl_ctx, ca_cert) != 0 ||
        (nc->ssl = SSL_new(nc->ssl_ctx)) == NULL) {
      ns_close_conn(nc);
      return NULL;
    } else {
      SSL_set_fd(nc->ssl, sock);
    }
  }
#endif

  return nc;
}

struct ns_connection *ns_add_sock(struct ns_mgr *s, sock_t sock,
                                  ns_callback_t callback, void *user_data) {
  struct ns_connection *conn;
  if ((conn = (struct ns_connection *) NS_MALLOC(sizeof(*conn))) != NULL) {
    memset(conn, 0, sizeof(*conn));
    ns_set_non_blocking_mode(sock);
    ns_set_close_on_exec(sock);
    conn->sock = sock;
    conn->user_data = user_data;
    conn->callback = callback;
    conn->mgr = s;
    conn->last_io_time = time(NULL);
    ns_add_conn(s, conn);
    DBG(("%p %d", conn, sock));
  }
  return conn;
}

struct ns_connection *ns_next(struct ns_mgr *s, struct ns_connection *conn) {
  return conn == NULL ? s->active_connections : conn->next;
}

void ns_broadcast(struct ns_mgr *mgr, ns_callback_t cb,void *data, size_t len) {
  struct ctl_msg ctl_msg;
  if (mgr->ctl[0] != INVALID_SOCKET && data != NULL &&
      len < sizeof(ctl_msg.message)) {
    ctl_msg.callback = cb;
    memcpy(ctl_msg.message, data, len);
    send(mgr->ctl[0], (char *) &ctl_msg,
         offsetof(struct ctl_msg, message) + len, 0);
    recv(mgr->ctl[0], (char *) &len, 1, 0);
  }
}

void ns_mgr_init(struct ns_mgr *s, void *user_data) {
  memset(s, 0, sizeof(*s));
  s->ctl[0] = s->ctl[1] = INVALID_SOCKET;
  s->user_data = user_data;

#ifdef _WIN32
  { WSADATA data; WSAStartup(MAKEWORD(2, 2), &data); }
#else
  // Ignore SIGPIPE signal, so if client cancels the request, it
  // won't kill the whole process.
  signal(SIGPIPE, SIG_IGN);
#endif

#ifndef NS_DISABLE_SOCKETPAIR
  do {
    ns_socketpair2(s->ctl, SOCK_DGRAM);
  } while (s->ctl[0] == INVALID_SOCKET);
#endif

#ifdef NS_ENABLE_SSL
  {static int init_done; if (!init_done) { SSL_library_init(); init_done++; }}
#endif
}

void ns_mgr_free(struct ns_mgr *s) {
  struct ns_connection *conn, *tmp_conn;

  DBG(("%p", s));
  if (s == NULL) return;
  // Do one last poll, see https://github.com/cesanta/mongoose/issues/286
  ns_mgr_poll(s, 0);

  if (s->ctl[0] != INVALID_SOCKET) closesocket(s->ctl[0]);
  if (s->ctl[1] != INVALID_SOCKET) closesocket(s->ctl[1]);
  s->ctl[0] = s->ctl[1] = INVALID_SOCKET;

  for (conn = s->active_connections; conn != NULL; conn = tmp_conn) {
    tmp_conn = conn->next;
    ns_close_conn(conn);
  }
}
// net_skeleton end
#endif  // NOEMBED_NET_SKELETON

#include <ctype.h>

#ifdef _WIN32         //////////////// Windows specific defines and includes
#include <io.h>       // For _lseeki64
#include <direct.h>   // For _mkdir
#ifndef S_ISDIR
#define S_ISDIR(x) ((x) & _S_IFDIR)
#endif
#ifdef stat
#undef stat
#endif
#ifdef lseek
#undef lseek
#endif
#ifdef popen
#undef popen
#endif
#ifdef pclose
#undef pclose
#endif
#define stat(x, y) mg_stat((x), (y))
#define fopen(x, y) mg_fopen((x), (y))
#define open(x, y) mg_open((x), (y))
#define lseek(x, y, z) _lseeki64((x), (y), (z))
#define popen(x, y) _popen((x), (y))
#define pclose(x) _pclose(x)
#define mkdir(x, y) _mkdir(x)
#ifndef __func__
#define STRX(x) #x
#define STR(x) STRX(x)
#define __func__ __FILE__ ":" STR(__LINE__)
#endif
/* MINGW has adopted the MSVC formatting for 64-bit ints as of gcc 4.4 till 4.8*/
#if (defined(__MINGW32__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4 && __GNUC_MINOR__ < 8))) || defined(_MSC_VER)
#define INT64_FMT   "I64d"
#else
#define INT64_FMT   "lld"
#endif
#define stat(x, y) mg_stat((x), (y))
#define fopen(x, y) mg_fopen((x), (y))
#define open(x, y) mg_open((x), (y))
#define flockfile(x)      ((void) (x))
#define funlockfile(x)    ((void) (x))
typedef struct _stati64 file_stat_t;
typedef HANDLE process_id_t;
#else                    ////////////// UNIX specific defines and includes
#include <dirent.h>
#include <dlfcn.h>
#include <inttypes.h>
#include <pwd.h>
#define O_BINARY 0
#define INT64_FMT PRId64
typedef struct stat file_stat_t;
typedef pid_t process_id_t;
#endif                  //////// End of platform-specific defines and includes

#include "mongoose.h"

#define MAX_REQUEST_SIZE 16384
#define IOBUF_SIZE 8192
#define MAX_PATH_SIZE 8192
#define DEFAULT_CGI_PATTERN "**.cgi$|**.pl$|**.php$"
#define CGI_ENVIRONMENT_SIZE 8192
#define MAX_CGI_ENVIR_VARS 64
#define ENV_EXPORT_TO_CGI "MONGOOSE_CGI"
#define PASSWORDS_FILE_NAME ".htpasswd"

#ifndef MONGOOSE_USE_WEBSOCKET_PING_INTERVAL
#define MONGOOSE_USE_WEBSOCKET_PING_INTERVAL 5
#endif

// Extra HTTP headers to send in every static file reply
#if !defined(MONGOOSE_USE_EXTRA_HTTP_HEADERS)
#define MONGOOSE_USE_EXTRA_HTTP_HEADERS ""
#endif

#ifndef MONGOOSE_POST_SIZE_LIMIT
#define MONGOOSE_POST_SIZE_LIMIT 0
#endif

#ifndef MONGOOSE_IDLE_TIMEOUT_SECONDS
#define MONGOOSE_IDLE_TIMEOUT_SECONDS 300
#endif

#ifdef NS_DISABLE_SOCKETPAIR
#define MONGOOSE_NO_CGI
#endif

#ifdef MONGOOSE_NO_FILESYSTEM
#define MONGOOSE_NO_AUTH
#define MONGOOSE_NO_CGI
#define MONGOOSE_NO_DAV
#define MONGOOSE_NO_DIRECTORY_LISTING
#define MONGOOSE_NO_LOGGING
#define MONGOOSE_NO_SSI
#define MONGOOSE_NO_DL
#endif

struct vec {
  const char *ptr;
  int len;
};

// For directory listing and WevDAV support
struct dir_entry {
  struct connection *conn;
  char *file_name;
  file_stat_t st;
};

// NOTE(lsm): this enum shoulds be in sync with the config_options.
enum {
  ACCESS_CONTROL_LIST,
#ifndef MONGOOSE_NO_FILESYSTEM
  ACCESS_LOG_FILE,
#ifndef MONGOOSE_NO_AUTH
  AUTH_DOMAIN,
#endif
#ifndef MONGOOSE_NO_CGI
  CGI_INTERPRETER,
  CGI_PATTERN,
#endif
  DAV_AUTH_FILE,
  DOCUMENT_ROOT,
#ifndef MONGOOSE_NO_DIRECTORY_LISTING
  ENABLE_DIRECTORY_LISTING,
#endif
#endif
  ENABLE_PROXY,
  EXTRA_MIME_TYPES,
#if !defined(MONGOOSE_NO_FILESYSTEM) && !defined(MONGOOSE_NO_AUTH)
  GLOBAL_AUTH_FILE,
#endif
#ifndef MONGOOSE_NO_FILESYSTEM
  HIDE_FILES_PATTERN,
  HEXDUMP_FILE,
  INDEX_FILES,
#endif
  LISTENING_PORT,
#ifndef _WIN32
  RUN_AS_USER,
#endif
#ifndef MONGOOSE_NO_SSI
  SSI_PATTERN,
#endif
  URL_REWRITES,
  NUM_OPTIONS
};

static const char *static_config_options[] = {
  "access_control_list", NULL,
#ifndef MONGOOSE_NO_FILESYSTEM
  "access_log_file", NULL,
#ifndef MONGOOSE_NO_AUTH
  "auth_domain", "mydomain.com",
#endif
#ifndef MONGOOSE_NO_CGI
  "cgi_interpreter", NULL,
  "cgi_pattern", DEFAULT_CGI_PATTERN,
#endif
  "dav_auth_file", NULL,
  "document_root",  NULL,
#ifndef MONGOOSE_NO_DIRECTORY_LISTING
  "enable_directory_listing", "yes",
#endif
#endif
  "enable_proxy", NULL,
  "extra_mime_types", NULL,
#if !defined(MONGOOSE_NO_FILESYSTEM) && !defined(MONGOOSE_NO_AUTH)
  "global_auth_file", NULL,
#endif
#ifndef MONGOOSE_NO_FILESYSTEM
  "hide_files_patterns", NULL,
  "hexdump_file", NULL,
  "index_files","index.html,index.htm,index.shtml,index.cgi,index.php",
#endif
  "listening_port", NULL,
#ifndef _WIN32
  "run_as_user", NULL,
#endif
#ifndef MONGOOSE_NO_SSI
  "ssi_pattern", "**.shtml$|**.shtm$",
#endif
  "url_rewrites", NULL,
  NULL
};

struct mg_server {
  struct ns_mgr ns_mgr;
  union socket_address lsa;   // Listening socket address
  mg_handler_t event_handler;
  char *config_options[NUM_OPTIONS];
};

// Local endpoint representation
union endpoint {
  int fd;                     // Opened regular local file
  struct ns_connection *nc;   // CGI or proxy->target connection
};

enum endpoint_type {
 EP_NONE, EP_FILE, EP_CGI, EP_USER, EP_PUT, EP_CLIENT, EP_PROXY
};

#define MG_HEADERS_SENT NSF_USER_1
#define MG_LONG_RUNNING NSF_USER_2
#define MG_CGI_CONN NSF_USER_3
#define MG_PROXY_CONN NSF_USER_4
#define MG_PROXY_DONT_PARSE NSF_USER_5

struct connection {
  struct ns_connection *ns_conn;  // NOTE(lsm): main.c depends on this order
  struct mg_connection mg_conn;
  struct mg_server *server;
  union endpoint endpoint;
  enum endpoint_type endpoint_type;
  char *path_info;
  char *request;
  int64_t num_bytes_recv; // Total number of bytes received
  int64_t cl;             // Reply content length, for Range support
  int request_len;  // Request length, including last \r\n after last header
};

#define MG_CONN_2_CONN(c) ((struct connection *) ((char *) (c) - \
  offsetof(struct connection, mg_conn)))

static void open_local_endpoint(struct connection *conn, int skip_user);
static void close_local_endpoint(struct connection *conn);
static void mg_ev_handler(struct ns_connection *nc, int ev, void *p);

static const struct {
  const char *extension;
  size_t ext_len;
  const char *mime_type;
} static_builtin_mime_types[] = {
  {".html", 5, "text/html"},
  {".htm", 4, "text/html"},
  {".shtm", 5, "text/html"},
  {".shtml", 6, "text/html"},
  {".css", 4, "text/css"},
  {".js",  3, "application/x-javascript"},
  {".ico", 4, "image/x-icon"},
  {".gif", 4, "image/gif"},
  {".jpg", 4, "image/jpeg"},
  {".jpeg", 5, "image/jpeg"},
  {".png", 4, "image/png"},
  {".svg", 4, "image/svg+xml"},
  {".txt", 4, "text/plain"},
  {".torrent", 8, "application/x-bittorrent"},
  {".wav", 4, "audio/x-wav"},
  {".mp3", 4, "audio/x-mp3"},
  {".mid", 4, "audio/mid"},
  {".m3u", 4, "audio/x-mpegurl"},
  {".ogg", 4, "application/ogg"},
  {".ram", 4, "audio/x-pn-realaudio"},
  {".xml", 4, "text/xml"},
  {".json",  5, "application/json"},
  {".xslt", 5, "application/xml"},
  {".xsl", 4, "application/xml"},
  {".ra",  3, "audio/x-pn-realaudio"},
  {".doc", 4, "application/msword"},
  {".exe", 4, "application/octet-stream"},
  {".zip", 4, "application/x-zip-compressed"},
  {".xls", 4, "application/excel"},
  {".tgz", 4, "application/x-tar-gz"},
  {".tar", 4, "application/x-tar"},
  {".gz",  3, "application/x-gunzip"},
  {".arj", 4, "application/x-arj-compressed"},
  {".rar", 4, "application/x-rar-compressed"},
  {".rtf", 4, "application/rtf"},
  {".pdf", 4, "application/pdf"},
  {".swf", 4, "application/x-shockwave-flash"},
  {".mpg", 4, "video/mpeg"},
  {".webm", 5, "video/webm"},
  {".mpeg", 5, "video/mpeg"},
  {".mov", 4, "video/quicktime"},
  {".mp4", 4, "video/mp4"},
  {".m4v", 4, "video/x-m4v"},
  {".asf", 4, "video/x-ms-asf"},
  {".avi", 4, "video/x-msvideo"},
  {".bmp", 4, "image/bmp"},
  {".ttf", 4, "application/x-font-ttf"},
  {NULL,  0, NULL}
};

#ifndef MONGOOSE_NO_THREADS
void *mg_start_thread(void *(*f)(void *), void *p) {
  return ns_start_thread(f, p);
}
#endif  // MONGOOSE_NO_THREADS

#ifndef MONGOOSE_NO_MMAP
#ifdef _WIN32
static void *mmap(void *addr, int64_t len, int prot, int flags, int fd,
                  int offset) {
  HANDLE fh = (HANDLE) _get_osfhandle(fd);
  HANDLE mh = CreateFileMapping(fh, 0, PAGE_READONLY, 0, 0, 0);
  void *p = MapViewOfFile(mh, FILE_MAP_READ, 0, 0, (size_t) len);
  CloseHandle(mh);
  return p;
}
#define munmap(x, y)  UnmapViewOfFile(x)
#define MAP_FAILED NULL
#define MAP_PRIVATE 0
#define PROT_READ 0
#else
#include <sys/mman.h>
#endif

void *mg_mmap(FILE *fp, size_t size) {
  void *p = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fileno(fp), 0);
  return p == MAP_FAILED ? NULL : p;
}

void mg_munmap(void *p, size_t size) {
  munmap(p, size);
}
#endif  // MONGOOSE_NO_MMAP

#if defined(_WIN32) && !defined(MONGOOSE_NO_FILESYSTEM)
// Encode 'path' which is assumed UTF-8 string, into UNICODE string.
// wbuf and wbuf_len is a target buffer and its length.
static void to_wchar(const char *path, wchar_t *wbuf, size_t wbuf_len) {
  char buf[MAX_PATH_SIZE * 2], buf2[MAX_PATH_SIZE * 2], *p;

  strncpy(buf, path, sizeof(buf));
  buf[sizeof(buf) - 1] = '\0';

  // Trim trailing slashes. Leave backslash for paths like "X:\"
  p = buf + strlen(buf) - 1;
  while (p > buf && p[-1] != ':' && (p[0] == '\\' || p[0] == '/')) *p-- = '\0';

  // Convert to Unicode and back. If doubly-converted string does not
  // match the original, something is fishy, reject.
  memset(wbuf, 0, wbuf_len * sizeof(wchar_t));
  MultiByteToWideChar(CP_UTF8, 0, buf, -1, wbuf, (int) wbuf_len);
  WideCharToMultiByte(CP_UTF8, 0, wbuf, (int) wbuf_len, buf2, sizeof(buf2),
                      NULL, NULL);
  if (strcmp(buf, buf2) != 0) {
    wbuf[0] = L'\0';
  }
}

static int mg_stat(const char *path, file_stat_t *st) {
  wchar_t wpath[MAX_PATH_SIZE];
  to_wchar(path, wpath, ARRAY_SIZE(wpath));
  DBG(("[%ls] -> %d", wpath, _wstati64(wpath, st)));
  return _wstati64(wpath, st);
}

static FILE *mg_fopen(const char *path, const char *mode) {
  wchar_t wpath[MAX_PATH_SIZE], wmode[10];
  to_wchar(path, wpath, ARRAY_SIZE(wpath));
  to_wchar(mode, wmode, ARRAY_SIZE(wmode));
  return _wfopen(wpath, wmode);
}

static int mg_open(const char *path, int flag) {
  wchar_t wpath[MAX_PATH_SIZE];
  to_wchar(path, wpath, ARRAY_SIZE(wpath));
  return _wopen(wpath, flag);
}
#endif // _WIN32 && !MONGOOSE_NO_FILESYSTEM

// A helper function for traversing a comma separated list of values.
// It returns a list pointer shifted to the next value, or NULL if the end
// of the list found.
// Value is stored in val vector. If value has form "x=y", then eq_val
// vector is initialized to point to the "y" part, and val vector length
// is adjusted to point only to "x".
static const char *next_option(const char *list, struct vec *val,
                               struct vec *eq_val) {
  if (list == NULL || *list == '\0') {
    // End of the list
    list = NULL;
  } else {
    val->ptr = list;
    if ((list = strchr(val->ptr, ',')) != NULL) {
      // Comma found. Store length and shift the list ptr
      val->len = list - val->ptr;
      list++;
    } else {
      // This value is the last one
      list = val->ptr + strlen(val->ptr);
      val->len = list - val->ptr;
    }

    if (eq_val != NULL) {
      // Value has form "x=y", adjust pointers and lengths
      // so that val points to "x", and eq_val points to "y".
      eq_val->len = 0;
      eq_val->ptr = (const char *) memchr(val->ptr, '=', val->len);
      if (eq_val->ptr != NULL) {
        eq_val->ptr++;  // Skip over '=' character
        eq_val->len = val->ptr + val->len - eq_val->ptr;
        val->len = (eq_val->ptr - val->ptr) - 1;
      }
    }
  }

  return list;
}

// Like snprintf(), but never returns negative value, or a value
// that is larger than a supplied buffer.
static int mg_vsnprintf(char *buf, size_t buflen, const char *fmt, va_list ap) {
  int n;
  if (buflen < 1) return 0;
  n = vsnprintf(buf, buflen, fmt, ap);
  if (n < 0) {
    n = 0;
  } else if (n >= (int) buflen) {
    n = (int) buflen - 1;
  }
  buf[n] = '\0';
  return n;
}

static int mg_snprintf(char *buf, size_t buflen, const char *fmt, ...) {
  va_list ap;
  int n;
  va_start(ap, fmt);
  n = mg_vsnprintf(buf, buflen, fmt, ap);
  va_end(ap);
  return n;
}

// Check whether full request is buffered. Return:
//   -1  if request is malformed
//    0  if request is not yet fully buffered
//   >0  actual request length, including last \r\n\r\n
static int get_request_len(const char *s, int buf_len) {
  const unsigned char *buf = (unsigned char *) s;
  int i;

  for (i = 0; i < buf_len; i++) {
    // Control characters are not allowed but >=128 are.
    // Abort scan as soon as one malformed character is found.
    if (!isprint(buf[i]) && buf[i] != '\r' && buf[i] != '\n' && buf[i] < 128) {
      return -1;
    } else if (buf[i] == '\n' && i + 1 < buf_len && buf[i + 1] == '\n') {
      return i + 2;
    } else if (buf[i] == '\n' && i + 2 < buf_len && buf[i + 1] == '\r' &&
               buf[i + 2] == '\n') {
      return i + 3;
    }
  }

  return 0;
}

// Skip the characters until one of the delimiters characters found.
// 0-terminate resulting word. Skip the rest of the delimiters if any.
// Advance pointer to buffer to the next word. Return found 0-terminated word.
static char *skip(char **buf, const char *delimiters) {
  char *p, *begin_word, *end_word, *end_delimiters;

  begin_word = *buf;
  end_word = begin_word + strcspn(begin_word, delimiters);
  end_delimiters = end_word + strspn(end_word, delimiters);

  for (p = end_word; p < end_delimiters; p++) {
    *p = '\0';
  }

  *buf = end_delimiters;

  return begin_word;
}

// Parse HTTP headers from the given buffer, advance buffer to the point
// where parsing stopped.
static void parse_http_headers(char **buf, struct mg_connection *ri) {
  size_t i;

  for (i = 0; i < ARRAY_SIZE(ri->http_headers); i++) {
    ri->http_headers[i].name = skip(buf, ": ");
    ri->http_headers[i].value = skip(buf, "\r\n");
    if (ri->http_headers[i].name[0] == '\0')
      break;
    ri->num_headers = i + 1;
  }
}

static const char *status_code_to_str(int status_code) {
  switch (status_code) {

    case 100: return "Continue";
    case 101: return "Switching Protocols";
    case 102: return "Processing";

    case 200: return "OK";
    case 201: return "Created";
    case 202: return "Accepted";
    case 203: return "Non-Authoritative Information";
    case 204: return "No Content";
    case 205: return "Reset Content";
    case 206: return "Partial Content";
    case 207: return "Multi-Status";
    case 208: return "Already Reported";
    case 226: return "IM Used";

    case 300: return "Multiple Choices";
    case 301: return "Moved Permanently";
    case 302: return "Found";
    case 303: return "See Other";
    case 304: return "Not Modified";
    case 305: return "Use Proxy";
    case 306: return "Switch Proxy";
    case 307: return "Temporary Redirect";
    case 308: return "Permanent Redirect";

    case 400: return "Bad Request";
    case 401: return "Unauthorized";
    case 402: return "Payment Required";
    case 403: return "Forbidden";
    case 404: return "Not Found";
    case 405: return "Method Not Allowed";
    case 406: return "Not Acceptable";
    case 407: return "Proxy Authentication Required";
    case 408: return "Request Timeout";
    case 409: return "Conflict";
    case 410: return "Gone";
    case 411: return "Length Required";
    case 412: return "Precondition Failed";
    case 413: return "Payload Too Large";
    case 414: return "URI Too Long";
    case 415: return "Unsupported Media Type";
    case 416: return "Requested Range Not Satisfiable";
    case 417: return "Expectation Failed";
    case 418: return "I\'m a teapot";
    case 422: return "Unprocessable Entity";
    case 423: return "Locked";
    case 424: return "Failed Dependency";
    case 426: return "Upgrade Required";
    case 428: return "Precondition Required";
    case 429: return "Too Many Requests";
    case 431: return "Request Header Fields Too Large";
    case 451: return "Unavailable For Legal Reasons";

    case 500: return "Internal Server Error";
    case 501: return "Not Implemented";
    case 502: return "Bad Gateway";
    case 503: return "Service Unavailable";
    case 504: return "Gateway Timeout";
    case 505: return "HTTP Version Not Supported";
    case 506: return "Variant Also Negotiates";
    case 507: return "Insufficient Storage";
    case 508: return "Loop Detected";
    case 510: return "Not Extended";
    case 511: return "Network Authentication Required";

    default:  return "Server Error";
  }
}

static int call_user(struct connection *conn, enum mg_event ev) {
  return conn != NULL && conn->server != NULL &&
    conn->server->event_handler != NULL ?
    conn->server->event_handler(&conn->mg_conn, ev) : MG_FALSE;
}

static void send_http_error(struct connection *conn, int code,
                            const char *fmt, ...) {
  const char *message = status_code_to_str(code);
  const char *rewrites = conn->server->config_options[URL_REWRITES];
  char headers[200], body[200];
  struct vec a, b;
  va_list ap;
  int body_len, headers_len, match_code;

  conn->mg_conn.status_code = code;

  // Invoke error handler if it is set
  if (call_user(conn, MG_HTTP_ERROR) == MG_TRUE) {
    close_local_endpoint(conn);
    return;
  }

  // Handle error code rewrites
  while ((rewrites = next_option(rewrites, &a, &b)) != NULL) {
    if ((match_code = atoi(a.ptr)) > 0 && match_code == code) {
      struct mg_connection *c = &conn->mg_conn;
      c->status_code = 302;
      mg_printf(c, "HTTP/1.1 %d Moved\r\n"
                "Location: %.*s?code=%d&orig_uri=%s&query_string=%s\r\n\r\n",
                c->status_code, b.len, b.ptr, code, c->uri,
                c->query_string == NULL ? "" : c->query_string);
      close_local_endpoint(conn);
      return;
    }
  }

  body_len = mg_snprintf(body, sizeof(body), "%d %s\n", code, message);
  if (fmt != NULL) {
    va_start(ap, fmt);
    body_len += mg_vsnprintf(body + body_len, sizeof(body) - body_len, fmt, ap);
    va_end(ap);
  }
  if ((code >= 300 && code <= 399) || code == 204) {
    // 3xx errors do not have body
    body_len = 0;
  }
  headers_len = mg_snprintf(headers, sizeof(headers),
                            "HTTP/1.1 %d %s\r\nContent-Length: %d\r\n"
                            "Content-Type: text/plain\r\n\r\n",
                            code, message, body_len);
  ns_send(conn->ns_conn, headers, headers_len);
  ns_send(conn->ns_conn, body, body_len);
  close_local_endpoint(conn);  // This will write to the log file
}

static void write_chunk(struct connection *conn, const char *buf, int len) {
  char chunk_size[50];
  int n = mg_snprintf(chunk_size, sizeof(chunk_size), "%X\r\n", len);
  ns_send(conn->ns_conn, chunk_size, n);
  ns_send(conn->ns_conn, buf, len);
  ns_send(conn->ns_conn, "\r\n", 2);
}

size_t mg_printf(struct mg_connection *conn, const char *fmt, ...) {
  struct connection *c = MG_CONN_2_CONN(conn);
  va_list ap;

  va_start(ap, fmt);
  ns_vprintf(c->ns_conn, fmt, ap);
  va_end(ap);

  return c->ns_conn->send_iobuf.len;
}

static void ns_forward(struct ns_connection *from, struct ns_connection *to) {
  DBG(("%p -> %p %lu bytes", from, to, (unsigned long)from->recv_iobuf.len));
  ns_send(to, from->recv_iobuf.buf, from->recv_iobuf.len);
  iobuf_remove(&from->recv_iobuf, from->recv_iobuf.len);
}

#ifndef MONGOOSE_NO_CGI
#ifdef _WIN32
struct threadparam {
  sock_t s;
  HANDLE hPipe;
};

static int wait_until_ready(sock_t sock, int for_read) {
  fd_set set;
  FD_ZERO(&set);
  FD_SET(sock, &set);
  select(sock + 1, for_read ? &set : 0, for_read ? 0 : &set, 0, 0);
  return 1;
}

static void *push_to_stdin(void *arg) {
  struct threadparam *tp = (struct threadparam *)arg;
  int n, sent, stop = 0;
  DWORD k;
  char buf[IOBUF_SIZE];

  while (!stop && wait_until_ready(tp->s, 1) &&
         (n = recv(tp->s, buf, sizeof(buf), 0)) > 0) {
    if (n == -1 && GetLastError() == WSAEWOULDBLOCK) continue;
    for (sent = 0; !stop && sent < n; sent += k) {
      if (!WriteFile(tp->hPipe, buf + sent, n - sent, &k, 0)) stop = 1;
    }
  }
  DBG(("%s", "FORWARED EVERYTHING TO CGI"));
  CloseHandle(tp->hPipe);
  free(tp);
  _endthread();
  return NULL;
}

static void *pull_from_stdout(void *arg) {
  struct threadparam *tp = (struct threadparam *)arg;
  int k = 0, stop = 0;
  DWORD n, sent;
  char buf[IOBUF_SIZE];

  while (!stop && ReadFile(tp->hPipe, buf, sizeof(buf), &n, NULL)) {
    for (sent = 0; !stop && sent < n; sent += k) {
      if (wait_until_ready(tp->s, 0) &&
          (k = send(tp->s, buf + sent, n - sent, 0)) <= 0) stop = 1;
    }
  }
  DBG(("%s", "EOF FROM CGI"));
  CloseHandle(tp->hPipe);
  shutdown(tp->s, 2);  // Without this, IO thread may get truncated data
  closesocket(tp->s);
  free(tp);
  _endthread();
  return NULL;
}

static void spawn_stdio_thread(sock_t sock, HANDLE hPipe,
                               void *(*func)(void *)) {
  struct threadparam *tp = (struct threadparam *)malloc(sizeof(*tp));
  if (tp != NULL) {
    tp->s = sock;
    tp->hPipe = hPipe;
    mg_start_thread(func, tp);
  }
}

static void abs_path(const char *utf8_path, char *abs_path, size_t len) {
  wchar_t buf[MAX_PATH_SIZE], buf2[MAX_PATH_SIZE];
  to_wchar(utf8_path, buf, ARRAY_SIZE(buf));
  GetFullPathNameW(buf, ARRAY_SIZE(buf2), buf2, NULL);
  WideCharToMultiByte(CP_UTF8, 0, buf2, wcslen(buf2) + 1, abs_path, len, 0, 0);
}

static process_id_t start_process(char *interp, const char *cmd,
                                  const char *env, const char *envp[],
                                  const char *dir, sock_t sock) {
  STARTUPINFOW si;
  PROCESS_INFORMATION pi;
  HANDLE a[2], b[2], me = GetCurrentProcess();
  wchar_t wcmd[MAX_PATH_SIZE], full_dir[MAX_PATH_SIZE];
  char buf[MAX_PATH_SIZE], buf4[MAX_PATH_SIZE], buf5[MAX_PATH_SIZE],
       cmdline[MAX_PATH_SIZE], *p;
  DWORD flags = DUPLICATE_CLOSE_SOURCE | DUPLICATE_SAME_ACCESS;
  FILE *fp;

  memset(&si, 0, sizeof(si));
  memset(&pi, 0, sizeof(pi));

  si.cb = sizeof(si);
  si.dwFlags = STARTF_USESTDHANDLES | STARTF_USESHOWWINDOW;
  si.wShowWindow = SW_HIDE;
  si.hStdError = GetStdHandle(STD_ERROR_HANDLE);

  CreatePipe(&a[0], &a[1], NULL, 0);
  CreatePipe(&b[0], &b[1], NULL, 0);
  DuplicateHandle(me, a[0], me, &si.hStdInput, 0, TRUE, flags);
  DuplicateHandle(me, b[1], me, &si.hStdOutput, 0, TRUE, flags);

  if (interp == NULL && (fp = fopen(cmd, "r")) != NULL) {
    buf[0] = buf[1] = '\0';
    fgets(buf, sizeof(buf), fp);
    buf[sizeof(buf) - 1] = '\0';
    if (buf[0] == '#' && buf[1] == '!') {
      interp = buf + 2;
      for (p = interp + strlen(interp) - 1;
           isspace(* (uint8_t *) p) && p > interp; p--) *p = '\0';
    }
    fclose(fp);
  }

  if (interp != NULL) {
    abs_path(interp, buf4, ARRAY_SIZE(buf4));
    interp = buf4;
  }
  abs_path(dir, buf5, ARRAY_SIZE(buf5));
  to_wchar(dir, full_dir, ARRAY_SIZE(full_dir));
  mg_snprintf(cmdline, sizeof(cmdline), "%s%s\"%s\"",
              interp ? interp : "", interp ? " " : "", cmd);
  to_wchar(cmdline, wcmd, ARRAY_SIZE(wcmd));

  if (CreateProcessW(NULL, wcmd, NULL, NULL, TRUE, CREATE_NEW_PROCESS_GROUP,
                     (void *) env, full_dir, &si, &pi) != 0) {
    spawn_stdio_thread(sock, a[1], push_to_stdin);
    spawn_stdio_thread(sock, b[0], pull_from_stdout);
  } else {
    CloseHandle(a[1]);
    CloseHandle(b[0]);
    closesocket(sock);
  }
  DBG(("CGI command: [%ls] -> %p", wcmd, pi.hProcess));

  // Not closing a[0] and b[1] because we've used DUPLICATE_CLOSE_SOURCE
  CloseHandle(si.hStdOutput);
  CloseHandle(si.hStdInput);
  //CloseHandle(pi.hThread);
  //CloseHandle(pi.hProcess);

  return pi.hProcess;