#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <dirent.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <openssl/sha.h>
#include <openssl/bio.h>
#include <openssl/buffer.h>
#include <openssl/evp.h>
#include <openssl/md5.h>

#include "sld.hh"

SLDaemon *SLDaemon::instance_ = 0;

SLDaemon::SLDaemon() : socket_fs_(0) {
  options_.conffile = "/etc/sldrc";
}

SLDaemon &SLDaemon::Instance() {
  if (instance_ == 0)
    instance_ = new SLDaemon();
  return *instance_;
}

void SLDaemon::usage(const char *argv0) const {
  std::cerr << "usage: "
	    << argv0
	    << " [-f conffile] [-d scriptdir] [-h] [-v] [-l login]"
	    << "[-p pass] [-H host] [-P port] [-V]"
	    << std::endl
	    << "  -f conffile  : read and load conf file (def: /etc/sldrc)." << std::endl
	    << "  -d scriptdir : Scripts directory." << std::endl
	    << "  -h           : Print this usage." << std::endl
	    << "  -v           : Verbose mode." << std::endl
	    << "  -l host      : Set login to host." << std::endl
	    << "  -p secret    : Set pass to secret." << std::endl
	    << "  -H name      : Set server host to name." << std::endl
	    << "  -P number    : Set server port to number." << std::endl
	    << "  -V           : Print version and exit." << std::endl;
}

SLDaemon::Options *SLDaemon::getoptions(int argc, char *argv[]) const {
  Options opt, *mopt;

  for (int i = 1; i < argc; ++i) {
    if (!strcmp(argv[i], "-h")) {
      usage(*argv);
      throw Error(ERR_USAGE);
    }
    else if (!strcmp(argv[i], "-v")) {
      opt.verbose = 1;
    }
    else if (!strcmp(argv[i], "-V")) {
      std::cout << "sl daemon version : " << VERSION << std::endl;
      exit(ERR_OK);
    }
    else if (!strcmp(argv[i], "-H")) {
      if (++i >= argc)
	throw Error(ERR_USAGE, "No enough argument for option -h");
      opt.server = string(argv[i]);
    }
    else if (!strcmp(argv[i], "-P")) {
      if (++i >= argc)
	throw Error(ERR_USAGE, "No enough argument for option -p");
      char *endptr;
      opt.port = strtol(argv[i], &endptr, 10);
      if (!(*argv[i] != '\0' && *endptr == '\0'))
	throw Error(ERR_USAGE, "Unable to convert port to a number");
    }
    else if (!strcmp(argv[i], "-f")) {
      if (++i >= argc)
	throw Error(ERR_USAGE, "No enough argument for option -f");
      opt.conffile = string(argv[i]);
    }
    else if (!strcmp(argv[i], "-d")) {
      if (++i >= argc)
	throw Error(ERR_USAGE, "No enough argument for option -d");
      opt.scriptdir = string(argv[i]);
    }
    else if (!strcmp(argv[i], "-l")) {
      if (++i >= argc)
	throw Error(ERR_USAGE, "No enough argument for option -l");
      opt.login = string(argv[i]);
    }
    else if (!strcmp(argv[i], "-p")) {
      if (++i >= argc)
	throw Error(ERR_USAGE, "No enough argument for option -p");
      opt.pass = string(argv[i]);
    }
    else
      throw Error(ERR_USAGE, (string) "Invalid options : " + argv[i]);
  }
  mopt = new Options();
  *mopt = opt;
  return mopt;
}

SLDaemon::Options *SLDaemon::getoptions(const string file) const {
  ifstream fs;
  char line[MAX_CONF_LINE_SIZE];
  int i=0;
  char name[11], value[MAX_CONF_LINE_SIZE - 10 + 1];
  SLDaemon::Options o;

  fs.open(file.c_str(), ifstream::in);

  if (!fs.is_open())
    return 0;

  while (fs.good()) {
    fs.getline(line, MAX_CONF_LINE_SIZE);
    if (fs.eof())
      break;
    sscanf(line, "%10[^=]=%2039s\n", name, value); //TODO: fix magic number

    if (!strcasecmp(name, "host"))
      o.login = value;
    else if (!strcasecmp(name, "pass"))
      o.pass = value;
    else if (!strcasecmp(name, "server"))
      o.server = value;
    else if (!strcasecmp(name, "port"))
      o.port = atoi(value);
    else if (!strcasecmp(name, "scriptdir"))
      o.scriptdir = value;
    else if (!strcasecmp(name, "verbose"))
      o.verbose = atoi(value);
    else
      std::cerr << "Invalid line " << i << ": " << line;
  }

  fs.close();

  return new SLDaemon::Options(o);
}

void SLDaemon::applyoptions(const Options *opt) {
  assert(opt);
  if (opt->server != "") options_.server = opt->server;
  if (opt->port != 0) options_.port = opt->port;
  if (opt->login != "") options_.login = opt->login;
  if (opt->pass != "") options_.pass = opt->pass;
  if (opt->verbose != 3) options_.verbose = opt->verbose;
  if (opt->conffile != "") options_.conffile = opt->conffile;
  if (opt->scriptdir != "") options_.scriptdir = opt->scriptdir;
}

void SLDaemon::check_options() const {
  // print info in verbose mode
  if (verbose()) {
    std::cout << "Server host is : " << options_.server << "." << std::endl;
    std::cout << "Server port is : " << options_.port << "." << std::endl;
    std::cout << "Daemon login is : " << options_.login << "." << std::endl;
    std::cout << "Daemon pass is : " << options_.pass << "." << std::endl;
    std::cout << "Daemon scripts directory is : " << options_.scriptdir << "." << std::endl;
    std::cout << "Verbose mode : " << verbose() << "." << std::endl;
  }

  // Check validy of arguement
  if (options_.server == "")
    throw Error(ERR_BADPARAM, "No server address specified");
  if (options_.port == 0)
    throw Error(ERR_BADPARAM, "No server port specified");
  if (options_.port < 1 || options_.port > 65535)
    throw Error(ERR_BADPARAM, "Bad server port number (1 - 65535)");
  if (options_.login == "")
    throw Error(ERR_BADPARAM, "No login specified");
  if (options_.pass == "")
    throw Error(ERR_BADPARAM, "No pass specified");
  if (options_.scriptdir == "")
    throw Error(ERR_BADPARAM, "No scripts directory specified");

  // Check dir script exist
  if (euidaccess(options_.scriptdir.c_str(), W_OK))
    throw Error(ERR_BADPARAM, "Unable to write into script directory");
}
void SLDaemon::run() {
  char *line;

  check_options();
  clean_dir(options_.scriptdir);
  connect();
  auth();
  while (1) {
    line = recvln();
    // call right handler
    try {
      if (!strcmp(line, "EXIT\n"))
	cmd_exit();
      else if (!strcmp(line, "VERSION\n"))
	cmd_version();
      else if (!strcmp(line, "STATUS\n"))
	cmd_status();
      else if (!strcmp(line, "LIST\n"))
	cmd_list();
      else if (!strcmp(line, "KILLALL\n"))
	cmd_killall();
      else if (!strcmp(line, "KILL\n"))
	cmd_kill(line);
      else if (!strncmp(line, "EXEC ", 4))
	cmd_exec(line);
      else if (!strncmp(line, "FILE ", 5))
	cmd_file(line);
      else if (!strcmp(line, "UPDATE\n"))
	cmd_update();
      else
	sendln("Invalid command.");
    }
    catch (const Error &e) {
      sendln(e.message());
      std::cerr << "!! " << e.message() << std::endl;
    }
    delete[] line;
  }
}

//******************************************************************************
// network functions
//******************************************************************************

void SLDaemon::connect() {
  struct sockaddr_in daddr;
  struct hostent *h;

  // close existing connexion
  if (socket_fs_ == 0)
    disconnect();

  // retrieve remote host info
  h = gethostbyname(options_.server.c_str());
  if (h == 0)
    throw Error(ERR_NET, hstrerror(h_errno));

  // create socket
  socket_fd_ = socket(PF_INET, SOCK_STREAM, 0);
  if (socket_fd_ == -1)
    throw Error(ERR_NET, strerror(errno));

  daddr.sin_family = AF_INET;
  daddr.sin_port = htons(options_.port);
  daddr.sin_addr = *((struct in_addr *) h->h_addr);
  memset(daddr.sin_zero, '\0', sizeof daddr.sin_zero);

  // connect
  if (::connect(socket_fd_, (struct sockaddr *) &daddr, sizeof daddr) == -1)
    throw Error(ERR_NET, strerror(errno));

  // initialize socket stream
  if ((socket_fs_ = fdopen(socket_fd_, "r+")) == 0)
    throw Error(ERR_NET, strerror(errno));
}

void SLDaemon::disconnect() {
  if (socket_fs_ == 0)
    return;
  if (fclose(socket_fs_))
    throw Error(ERR_NET, strerror(errno));
  socket_fs_ = 0;
}

void SLDaemon::send(long int i) {
  fprintf(socket_fs_, "%li", i);
}

void SLDaemon::send(const string str, bool buf) {
  send(str.c_str(), str.length(), buf);
}

void SLDaemon::send(const char *data, size_t len, bool buf) {
  if (len == 0)
    return;
  if (fwrite(data, 1, len, socket_fs_) != len)
    throw Error(ERR_NET, strerror(errno));
  if (!buf && fflush(socket_fs_))
    throw Error(ERR_NET, strerror(errno));
}

void SLDaemon::sendln(const string &s) {
  if (!fprintf(socket_fs_, "%s\n", s.c_str()))
    throw Error(ERR_NET, strerror(errno));
  if (verbose())
    std::cout << SND_DATA << s << std::endl;
}

char *SLDaemon::recv(size_t size) {
  char *data = new char[size];

  if (fread(data, 1, size, socket_fs_) != size) {
    delete[] data;
    throw Error(ERR_NET, strerror(errno));
  }
  return data;
}

void SLDaemon::recv(size_t size, const string &filename) {
  char *data = recv(size);
  FILE *fs = fopen(filename.c_str(), "w");
  if (fs == 0)
    throw Error(ERR_FILE, (string) "recv: fopen: " + strerror(errno));
  if (fwrite(data, 1, size, fs) != size)
    throw Error(ERR_FILE, (string) "recv: fwrite: " + strerror(errno));
  if (fclose(fs))
    throw Error(ERR_FILE, (string) "recv: fclose: " + strerror(errno));
}

char *SLDaemon::recvln() {
  char *line = new char[MAX_LINE_SIZE];

  if (fgets(line, MAX_LINE_SIZE, socket_fs_) == 0) {
    delete[] line;
    throw Error(ERR_FILE, (string) "recvln: " + strerror(errno));
  }
  if (verbose())
    std::cout << RCV_DATA << line;

  return line;
}

void SLDaemon::flush() {
  if (fflush(socket_fs_))
    throw Error(ERR_NET, strerror(errno));
}

//******************************************************************************
// protocol functions
//******************************************************************************

void SLDaemon::auth() {
  unsigned char md[SHA_DIGEST_LENGTH];
  char buf[MAX_LINE_SIZE];
  char *buf2 = "";
  BIO *bmem, *b64;
  BUF_MEM *bptr;

  SHA1((const unsigned char *) options_.pass.c_str(), options_.pass.length(), md);

  b64 = BIO_new(BIO_f_base64());
  bmem = BIO_new(BIO_s_mem());
  b64 = BIO_push(b64, bmem);
  BIO_write(b64, md, SHA_DIGEST_LENGTH);
  BIO_flush(b64);
  BIO_get_mem_ptr(b64, &bptr);

  if (bptr->length > 0) {
    buf2 = new char[bptr->length];
    memcpy(buf2, bptr->data, bptr->length-1);
    buf2[bptr->length-1] = 0;
  }

  snprintf(buf, MAX_LINE_SIZE, "HOST %s", options_.login.c_str());
  sendln(buf);

  snprintf(buf, MAX_LINE_SIZE, "PASS %s", buf2);
  sendln(buf);

  if (bptr->length > 0)
    delete[] buf2;

  BIO_free_all(b64);

  return;
}

//******************************************************************************
// command functions
//******************************************************************************

void SLDaemon::cmd_exit() {
  sendln("Bye.");
  disconnect();
  exit(ERR_OK);
}

void SLDaemon::cmd_version() {
  sendln(VERSION);
}

void SLDaemon::cmd_exec(const char *line) {
  assert(line);

  // build path
  char buf[MAX_LINE_SIZE];
  if (sscanf(line, "EXEC %512s\n", buf) != 1) {  //FIXME: Bad static magic number
    sendln("EXEC: Syntax error.");
    return;
  }
  string path = options_.scriptdir + "/" +  buf;

  // Check transversal path attack
  if (strchr(buf, '/')) {
    sendln("EXEC: Invalid character in job name.");
    return;
  }

  // Check if file exist
  struct stat st;
  int ret = lstat(path.c_str(), &st);
  if (ret) {
    char msg[MAX_LINE_SIZE];
    snprintf(msg, MAX_LINE_SIZE, "EXEC: %s: %s.", buf, strerror(errno));
    sendln(msg);
    return;
  }
  // check for exec flag
  if (st.st_mode & S_IXUSR != S_IXUSR) {
    sendln("EXEC: no exec flag.");
    return;
  }
  // check file owner
  if (st.st_uid != getuid()) {
    sendln("EXEC: Bad file owner.");
    return;
  }

  // flush before fork
  flush();

  //Create new process
  pid_t pid = fork();
  if (pid == -1) {
    sendln((string) "EXEC: Unable to fork: " + strerror(errno) + ".");
    return;
  }

  // Father job
  if (pid > 0) {
    // reg job
    SLDaemon::Job j(pid, buf, time(0));
    jobs_.insert(j);

    // send job info
    snprintf(buf, MAX_LINE_SIZE,
	     "EXEC: %s, pid: %d, start at: %ld.",
	     j.name.c_str(), j.pid, j.start_time);
    sendln(buf);

    // allow sun to start
    if (kill(pid, SIGCONT)) {
      perror("sld: cmd_exec");
      jobs_.erase(j);
    }
  }
  // Son job
  else if (pid == 0) {
    // Wait father registration stuff before doing something else
    // so we suspend execution
    if (kill(getpid(), SIGSTOP)) {
      perror("sld: cmd_exec");
      return;
    }

    // try to run job
    if (dup2(socket_fd_, STDOUT_FILENO) == -1) {
      perror(">> dup2");
      exit(ERR_UNKNOWN);
    }
    if (dup2(socket_fd_, STDERR_FILENO) == -1) {
      perror(">> dup2");
      exit(ERR_UNKNOWN);
    }
    execl(path.c_str(), basename(path.c_str()), 0);
    perror(string("sld: execl " + path).c_str());
    exit(ERR_UNKNOWN);
  }
}

void SLDaemon::cmd_file(const char *line) {
  char *buf;
  int ret;

  assert(line);

  // get filename
  char filename[MAX_LINE_SIZE];
  if (sscanf(line, "FILE %512s\n", filename) != 1) { //FIXME: bad magic size
    sendln("FILE: Syntax error.");
    return;
  }

  // Check transversal path attack
  if (strchr(filename, '/')) {
    sendln("FILE: Invalid character in filename.");
    return;
  }

  string target = options_.scriptdir + "/" + filename;

  //get size
  int size;
  buf = recvln();
  ret = sscanf(buf, "SIZE %i\n", &size);
  delete[] buf;
  if (ret != 1) {
    sendln("FILE: Invalid size parameter.");
    return;
  }

  //get md5
  char md5[MAX_LINE_SIZE];
  buf = recvln();
  ret = sscanf(buf, "MD5 %512s\n", md5); //FIXME: bad magic size
  delete[] buf;
  if (ret != 1) {
    sendln("FILE: Invalid md5 parameter.");
    return;
  }

  //get data
  try {
    recv(size, target);
  }
  catch (const Error &err) {
    if (err.code() == ERR_FILE) {
      sendln("FILE: Data transfer error.");
      return;
    }
    throw;
  }

  // check MD5
  if (SLDaemon::md5(target) != string(md5)) {
    sendln("FILE: file " + target + ": Invalid MD5.");
    unlink(target.c_str());
    return;
 }

  // proceed chown
  if (chown(target.c_str(), getuid(), getgid())) {
    sendln("FILE: chown of " + target + ": Unable to chown.");
    unlink(target.c_str());
    return;
  }

  // proceed chmod
  if (chmod(target.c_str(), S_IRUSR | S_IWUSR | S_IXUSR)) {
    sendln("FILE: chmod of " + target + ": Unable to chmod.");
    unlink(target.c_str());
    return;
  }

  sendln("FILE: Transfer of " + target + ": OK.");
}

void SLDaemon::cmd_update() {
  char *buf;
  int ret;

  // get filename
  const string &target = getbinpath();

  //get size
  int size;
  buf = recvln();
  ret = sscanf(buf, "SIZE %i\n", &size);
  delete[] buf;
  if (ret != 1) {
    sendln("UPDATE: Syntax error.");
    return;
  }

  //get md5
  char md5[MAX_LINE_SIZE];
  buf = recvln();
  ret = sscanf(buf, "MD5 %512s\n", md5); //FIXME: bad magic size
  delete[] buf;
  if (ret != 1) {
    sendln("UPDATE: Invalid md5 parameter.");
    return;
  }

  // find tempory filename
  char tempsld[PATH_MAX] = "/tmp/sldXXXXXX";
  int tempsld_fd = mkstemp(tempsld);

  if (tempsld_fd == 0) {
    sendln((string) "UPDATE: mkstemp: " + strerror(errno) + ".");
    return;
  }
  close(tempsld_fd);

  //get data
  try {
    recv(size, tempsld);
  }
  catch (const Error &err) {
    if (err.code() == ERR_FILE) {
      sendln("UPDATE: " + err.message() + ".");
      unlink(tempsld);
      return;
    }
    throw;
  }

  // check MD5
  if (SLDaemon::md5(tempsld) != string(md5)) {
    sendln((string) "UPDATE: file " + tempsld + ": Invalid MD5.");
    unlink(tempsld);
    return;
 }

  // copy file to its right destination
  unlink(target.c_str());
  cp(tempsld, target.c_str());


  // check MD5
  if (SLDaemon::md5(target.c_str()) != string(md5)) {
    sendln("UPDATE: file " + target + ": Invalid MD5.");
    unlink(tempsld);
    return;
 }


  // proceed chown
  if (chown(target.c_str(), getuid(), getgid())) {
    sendln("FILE: chown of " + target + ": Unable to chown.");
    unlink(target.c_str());
    return;
  }

  // proceed chmod
  if (chmod(target.c_str(), S_IRUSR | S_IWUSR | S_IXUSR)) {
    sendln("FILE: chmod of " + target + ": Unable to chmod.");
    unlink(target.c_str());
    return;
  }

  sendln("UPDATE: Transfer of " + target + ": OK.");
}

void SLDaemon::cmd_list() {
  FILE *fls = popen(string("ls -1A " + options_.scriptdir).c_str(), "r");
  if (fls == 0) {
    sendln("LIST: Unable to list " + options_.scriptdir + ".");
    return;
  }

  char buf[255];
  size_t len;
  try {
    while ((len = fread(buf, 1, 255, fls)) > 0)
      send(buf, len);
    sendln("LIST: data send.");
  }
  catch (...) {
    pclose(fls);
    throw;
  }
}

void SLDaemon::cmd_status() {
  t_job::iterator i;
  time_t t = time(0);
  char buf[MAX_LINE_SIZE];

  if (jobs_.size() == 0)
    return;

  sendln("STATUS of");
  for (i = jobs_.begin(); i != jobs_.end(); ++i) {
    snprintf(buf, MAX_LINE_SIZE,
	     " job: %s, pid: %d, start at: %ld, since: %ld seconds.",
	     i->name.c_str(), i->pid, i->start_time,t - i->start_time);
    sendln(buf);
  }
}

void SLDaemon::cmd_kill(const char *line) {
  t_job::iterator i;
  char buf[MAX_LINE_SIZE];

  // retrieve pid
  int pid;
  if (sscanf(line, "KILL %i\n", &pid) != 1) {
    sendln("KILL: Syntax error.");
    return;
  }

  for (i = jobs_.begin(); i != jobs_.end(); ++i)
    if (pid == i->pid) {
      int ret = kill(i->pid, SIGKILL);
      snprintf(buf, MAX_LINE_SIZE, "KILL: kill -SIGKILL %d (%s), return %d (%s).",
	       i->pid, i->name.c_str(), ret, ((ret == -1) ? strerror(errno) : "OK" ));
      sendln(buf);
    }
}

void SLDaemon::cmd_killall() {
  t_job::iterator i;
  char buf[MAX_LINE_SIZE];

  for (i = jobs_.begin(); i != jobs_.end(); ++i) {
    int ret = kill(i->pid, SIGKILL);
    snprintf(buf, MAX_LINE_SIZE, "KILL: kill -SIGKILL %d (%s), return %d (%s).",
	     i->pid, i->name.c_str(), ret, ((ret == -1) ? strerror(errno) : "OK" ));
    sendln(buf);
  }
}

//******************************************************************************
// others functions
//******************************************************************************

string SLDaemon::md5(const string &file) const {
  MD5_CTX ctx;
  FILE *fs;
  size_t len;
  char buf[512];
  char md[MD5_DIGEST_LENGTH];
  char digest[MD5_DIGEST_LENGTH * 2 + 1];

  if (!MD5_Init(&ctx))
    return "";
  if ((fs = fopen(file.c_str(), "r")) == 0)
    return "";
  while ((len = fread(buf, 1, 512, fs)) > 0)
    if (!MD5_Update(&ctx, buf, len))
      break;
  if (!MD5_Final((unsigned char*)md, &ctx))
    return "";
  for(len = 0; len < MD5_DIGEST_LENGTH; ++len) {
    sprintf(digest + (len * 2), "%02x", (unsigned char) md[len]);
  }
  digest[MD5_DIGEST_LENGTH * 2] = 0;
  return string(digest);
}

void SLDaemon::clean_dir(const string &dir) const {
  DIR *ds;
  struct dirent *de;

  ds = opendir(dir.c_str());
  if (ds == 0)
    throw Error(ERR_FILE, "clear_dir: Unable to read dir script");

  while ((de = readdir(ds))) {
    if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, ".."))
      continue;
    if (remove(de->d_name)) {
      closedir(ds);
      throw Error(ERR_FILE,(string) "clear_dir: remove("+ de->d_name + "): " + strerror(errno));
    }
  }
  closedir(ds);
}

//******************************************************************************
// Class Options functions
//******************************************************************************

SLDaemon::Options::Options() {
  this->port = 0;
  this->verbose = 3;
}

void SLDaemon::Options::print() {
  std::cout << "server: " << server << std::endl;
  std::cout << "port: " << port << std::endl;
  std::cout << "host login: " << login << std::endl;
  std::cout << "host pass: " << pass << std::endl;
  std::cout << "script directory: " << scriptdir << std::endl;
  std::cout << "configuration file: " << conffile << std::endl;
  std::cout << "verbose level: " << verbose << std::endl;
}

//******************************************************************************
// Class Job functions
//******************************************************************************

SLDaemon::Job::Job(int p, const string &s, time_t t) : pid(p), name(s), start_time(t) {}

bool SLDaemon::Job::operator()(const SLDaemon::Job &a, const SLDaemon::Job &b) {
  return a.pid < b.pid;
}

//******************************************************************************
// Friends Class functions
//******************************************************************************

void sigchild(int) {
  int status;
  SLDaemon &d = SLDaemon::Instance();
  typedef SLDaemon::t_job t_job;
  t_job::iterator i;
  t_job &jobs_ = d.jobs_;
  pid_t pid;

  // Retrieve a pid
  while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
    time_t t = time(0);
    for (i = jobs_.begin(); i != jobs_.end(); ++i) {
      if (i->pid == pid) {
	char buf[MAX_LINE_SIZE];
	snprintf(buf, MAX_LINE_SIZE,
		 "JOB: %s, pid: %d, end at: %ld, since: %ld, return: %d\n",
		 i->name.c_str(), i->pid,  t, t - i->start_time,
		 WEXITSTATUS(status));
	write(d.socket_fd_, buf, strlen(buf));
	if (d.verbose())
	  std::cout << SND_DATA << buf;
	jobs_.erase(i);
	break;
      }
    }
  }
}