zoneminder/src/zm_fifo_stream.cpp

//
// ZoneMinder Fifo Debug
// Copyright (C) 2019 ZoneMinder LLC
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//

#include "zm_fifo_stream.h"
#include "zm_fifo.h"
#include "zm_monitor.h"
#include "zm_signal.h"
#include <fcntl.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <unistd.h>

#define RAW_BUFFER 512
bool FifoStream::sendRAWFrames() {
  static unsigned char buffer[RAW_BUFFER];
  int fd = open(stream_path.c_str(), O_RDONLY);
  if ( fd < 0 ) {
    Error("Can't open %s: %s", stream_path.c_str(), strerror(errno));
    return false;
  }
  while ( (bytes_read = read(fd, buffer, RAW_BUFFER)) ) {
    if ( bytes_read == 0 )
      continue;
    if ( bytes_read < 0 ) {
      Error("Problem during reading: %s", strerror(errno));
      close(fd);
      return false;
    }
    if ( fwrite(buffer, bytes_read, 1, stdout) != 1 ) {
      if ( !zm_terminate ) 
        Error("Problem during writing: %s", strerror(errno));
      close(fd);
      return false;
    }
    fflush(stdout);
  }
  close(fd);
  return true;
}

bool FifoStream::sendMJEGFrames() {
  static unsigned char buffer[ZM_MAX_IMAGE_SIZE];
  int fd = open(stream_path.c_str(), O_RDONLY);
  if ( fd < 0 ) {
    Error("Can't open %s: %s", stream_path.c_str(), strerror(errno));
    return false;
  }
  total_read = 0;
  while (
      (bytes_read = read(fd, buffer+total_read, ZM_MAX_IMAGE_SIZE-total_read))
      ) {
    if ( bytes_read < 0 ) {
      Error("Problem during reading: %s", strerror(errno));
      close(fd);
      return false;
    }
    total_read += bytes_read;
  }
  close(fd);

  if ( (total_read == 0) || (frame_count%frame_mod != 0) )
    return true;

  if ( fprintf(stdout,
        "--" BOUNDARY "\r\n"
      "Content-Type: image/jpeg\r\n"
      "Content-Length: %d\r\n\r\n",
      total_read) < 0 ) {
    Error("Problem during writing: %s", strerror(errno));
    return false;
  }

  if ( fwrite(buffer, total_read, 1, stdout) != 1 ) {
    Error("Problem during reading: %s", strerror(errno));
    return false;
  }
  fprintf(stdout, "\r\n\r\n");
  fflush(stdout);
  last_frame_sent = now;
  frame_count++;
  return true;
}

void FifoStream::setStreamStart(const std::string &path) {
  stream_path = path;
}

void FifoStream::setStreamStart(int monitor_id, const char *format) {
  std::string diag_path;
  std::shared_ptr<Monitor> monitor = Monitor::Load(monitor_id, false, Monitor::QUERY);

  if (!strcmp(format, "reference")) {
    diag_path = stringtf("%s/diagpipe-r-%u.jpg", staticConfig.PATH_SOCKS.c_str(), monitor->Id());
    stream_type = MJPEG;
  } else if (!strcmp(format, "delta")) {
    diag_path = stringtf("%s/diagpipe-d-%u.jpg", staticConfig.PATH_SOCKS.c_str(), monitor->Id());
    stream_type = MJPEG;
  } else {
    if (strcmp(format, "raw")) {
      Warning("Unknown or unspecified format.  Defaulting to raw");
    }

    diag_path = stringtf("%s/dbgpipe-%u.log", staticConfig.PATH_SOCKS.c_str(), monitor->Id());
    stream_type = RAW;
  }

  setStreamStart(diag_path);
}

void FifoStream::runStream() {
  if (stream_type == MJPEG) {
    fprintf(stdout, "Content-Type: multipart/x-mixed-replace;boundary=" BOUNDARY "\r\n\r\n");
  } else {
    fprintf(stdout, "Content-Type: text/html\r\n\r\n");
  }

  /* only 1 person can read from a fifo at a time, so use a lock */
  std::string lock_file = stringtf("%s.rlock", stream_path.c_str());
  Fifo::file_create_if_missing(lock_file, false);
  Debug(1, "Locking %s", lock_file.c_str());

  int fd_lock = open(lock_file.c_str(), O_RDONLY);
  if (fd_lock < 0) {
    Error("Can't open %s: %s", lock_file.c_str(), strerror(errno));
    return;
  }

  int res = flock(fd_lock, LOCK_EX | LOCK_NB);
  while ((res < 0 and errno == EAGAIN) and (!zm_terminate)) {
    Warning("Flocking problem on %s: - %s", lock_file.c_str(), strerror(errno));
    sleep(1);
    res = flock(fd_lock, LOCK_EX | LOCK_NB);
  }

  if (res < 0) {
    Error("Flocking problem on %d != %d %s: - %s", EAGAIN, res, lock_file.c_str(), strerror(errno));
    close(fd_lock);
    return;
  }

  while (!zm_terminate) {
    now = std::chrono::system_clock::now();
    checkCommandQueue();

    if (stream_type == MJPEG) {
      if (!sendMJEGFrames())
        zm_terminate = true;
    } else {
      if (!sendRAWFrames())
        zm_terminate = true;
    }
  }

  close(fd_lock);
}