/* $Id: sfskeygen.C,v 1.32 2001/08/19 00:27:15 dm Exp $ */

/*
 *
 * Copyright (C) 1999 Michael Kaminsky (kaminsky@lcs.mit.edu)
 * Copyright (C) 1998, 1999 David Mazieres (dm@uun.org)
 *
 * 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, 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 *
 */

#include "sfskey.h"
#include "srp.h"

str
keysave (str keyfile, const sfskey *sk, bool excl)
{
  assert (!sk->pwd || sk->cost);
  str s = export_rabin_priv (*sk->key, sk->pwd, sk->keyname, sk->cost);
  if (!s)
    panic ("export_rabin_priv failed\n");

  ptr<rabin_priv> x = import_rabin_priv (s, sk->pwd);
  assert (x);
  assert (sk->key->p == x->p);
  assert (sk->key->q == x->q);

  if (!str2file (keyfile, s, 0600, excl))
    return keyfile << ": " << strerror (errno);
  return NULL;
}

str
defkeyname (str user)
{
  if (!user && !(user = myusername ()))
    fatal << "cannot find login name\n";
  if (str host = myname ())
    return user << "@" << host;
  else
    fatal << "cannot find local host name\n";
}

str
keygen (sfskey *sk, u_int nbits, str prompt,
	bool askname, bool nopwd, bool nokbdnoise)
{
  if (!nbits)
    nbits = sfs_pubkeysize;
  if (nbits < sfs_minpubkeysize)
    return strbuf ("public keys must be at least %d bits", sfs_minpubkeysize);

  random_start ();
  rndaskcd ();

  sk->key = NULL;
  if (!sk->keyname)
    sk->keyname = defkeyname ();
  
  if (!prompt)
    prompt = sk->keyname;
  warnx << "Creating new key for " << prompt << ".\n";

  if (askname)
    sk->keyname = getline ("       Key Name: ", sk->keyname);
  else
    warnx << "       Key Name: " << sk->keyname << "\n";
  if (nopwd)
    sk->pwd = NULL;
  else if (!(sk->pwd = getpwdconfirm ("Enter passprase: ")))
    return "Aborted.";
  if (!nokbdnoise)
    rndkbd ();
  random_init ();
  if (!sk->cost)
    sk->cost = sfs_pwdcost;

  sk->key = New refcounted<rabin_priv> (rabin_keygen (nbits));

  return NULL;
}

void
sfskey_edit (int argc, char **argv)
{
  bool nopwd = false;
  u_int cost = 0;
  str outfile, comment, keyname;

  int ch;
  while ((ch = getopt (argc, argv, "Po:c:n:")) != -1)
    switch (ch) {
    case 'P':
      nopwd = true;
      break;
    case 'o':
      outfile = optarg;
      break;
    case 'c':
      if (!convertint (optarg, &cost))
	usage ();
      if (cost > sfs_maxpwdcost)
	fatal ("password cost must be far less than %d\n", sfs_minpubkeysize);
      break;
    case 'n':
      comment = optarg;
      break;
    default:
      usage ();
      break;
    }

  if (argc == optind)
    keyname = defkey ();
  else if (argc == optind + 1)
    keyname = argv[optind];
  else
    usage ();

  if ((outfile && isremote (outfile)) || (!outfile && isremote (keyname)))
    fatal ("must specify a local output file with -o\n");
  errno = EEXIST;
  if (outfile && (access (outfile, 0) >= 0 || errno != ENOENT))
    fatal << outfile << ": " << strerror (errno) << "\n";

  random_start ();

  if (outfile)
    warnx << "Copying key " << keyname << " to " << outfile << ".\n";
  else if (nopwd)
    warnx << "Removing passphrase from key " << keyname << ".\n";
  else
    warnx << "Editing passphrase on key " << keyname << ".\n";

  sfskey k;
  if (str err = keyfetch (&k, keyname))
    fatal << err << "\n";

  if (cost)
    k.cost = cost;
  if (comment)
    k.keyname = comment;
  if (nopwd)
    k.pwd = NULL;
  else if (!isremote (keyname))
    k.pwd = getpwdconfirm ("  New passphrase: ");

  random_init ();

  if (str err = keysave (outfile ? outfile : keyname, &k, outfile))
    fatal << err << "\n";
  exit (0);
}

void
sfskey_gen (int argc, char **argv)
{
  bool nopwd = false, nokbdnoise = false;
  u_int nbits = 0, cost = 0;
  str keyname, keyfile;

  int ch;
  while ((ch = getopt (argc, argv, "b:c:n:KP")) != -1)
    switch (ch) {
    case 'b':
      if (!convertint (optarg, &nbits))
	usage ();
      break;
    case 'c':
      if (!convertint (optarg, &cost))
	usage ();
      if (cost > sfs_maxpwdcost)
	fatal ("password cost must be far less than %d\n", sfs_minpubkeysize);
      break;
    case 'n':
      keyname = optarg;
      break;
    case 'K':
      nokbdnoise = true;
      break;
    case 'P':
      nopwd = true;
      break;
    default:
      usage ();
      break;
    }

  if (optind == argc) {
    agent_mkdir ();
    keyfile = defkey ();
  }
  else if (optind + 1 == argc)
    keyfile = argv[optind];
  else
    usage ();
  if (isremote (keyfile))
    fatal << keyfile << ": not local\n(Try ./" << keyfile
	  << " if you really want '@' in the file name.)\n";

  errno = EEXIST;
  if (access (keyfile, 0) >= 0 || errno != ENOENT)
    fatal << keyfile << "; " << strerror (errno) << "\n";

  sfskey k;
  k.keyname = keyname;
  k.cost = cost;
  if (str err = keygen (&k, nbits, keyfile, !keyname, nopwd, nokbdnoise))
    fatal << err << "\n";
  if (str err = keysave (keyfile, &k))
    fatal << err << "\n";

  exit (0);
}

void
sfskey_srpgen (int argc, char **argv)
{
  u_int nbits = sfs_pubkeysize;
  int ch;
  while ((ch = getopt (argc, argv, "b:c:n:KP")) != -1)
    switch (ch) {
    case 'b':
      if (!convertint (optarg, &nbits))
	usage ();
      if (nbits < srp_base::minprimsize)
	fatal ("srp primes must be at least %d bits\n",
	       srp_base::minprimsize);
      break;
    default:
      usage ();
      break;
    }
  if (optind + 1 != argc)
    usage ();

  random_set_seedfile (RANDOM_SEED);
  random_init ();

  warnx ("Generating SRP parameters.  This can take several minutes...");
  err_flush ();
  bigint N, g;
  srp_base::genparam (nbits, &N, &g);
  warnx (" done\n");

  if (!str2file (argv[optind], export_srp_params (N, g), 0444))
    fatal ("%s: %m\n", argv[optind]);
  exit (0);
}