/* call-agent.c - divert operations to the agent
 *	Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
 *
 * This file is part of GnuPG.
 *
 * GnuPG 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.
 *
 * GnuPG 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
 */

#if 0  /* lety Emacs display a red warning */
#error fixme: this shares a lof of code with the file in ../sm
#endif

#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h> 
#include <time.h>
#include <assert.h>
#ifdef HAVE_LOCALE_H
#include <locale.h>
#endif
#include <assuan.h>

#include "gpg.h"
#include "util.h"
#include "membuf.h"
#include "options.h"
#include "i18n.h"
#include "call-agent.h"

#ifndef DBG_ASSUAN
# define DBG_ASSUAN 1
#endif

static ASSUAN_CONTEXT agent_ctx = NULL;
static int force_pipe_server = 0;

struct cipher_parm_s {
  ASSUAN_CONTEXT ctx;
  const char *ciphertext;
  size_t ciphertextlen;
};

struct genkey_parm_s {
  ASSUAN_CONTEXT ctx;
  const char *sexp;
  size_t sexplen;
};

struct learn_parm_s {
  int error;
  ASSUAN_CONTEXT ctx;
  struct membuf *data;
};


/* Try to connect to the agent via socket or fork it off and work by
   pipes.  Handle the server's initial greeting */
static int
start_agent (void)
{
  int rc = 0;
  char *infostr, *p;
  ASSUAN_CONTEXT ctx;
  char *dft_display = NULL;
  char *dft_ttyname = NULL;
  char *dft_ttytype = NULL;
  char *old_lc = NULL;
  char *dft_lc = NULL;

  if (agent_ctx)
    return 0; /* fixme: We need a context for each thread or serialize
                 the access to the agent. */

  infostr = force_pipe_server? NULL : getenv ("GPG_AGENT_INFO");
  if (!infostr)
    {
      const char *pgmname;
      const char *argv[3];
      int no_close_list[3];
      int i;

      if (opt.verbose)
        log_info (_("no running gpg-agent - starting one\n"));

      if (fflush (NULL))
        {
          gpg_error_t tmperr = gpg_error_from_errno (errno);
          log_error ("error flushing pending output: %s\n", strerror (errno));
          return tmperr;
        }

      if (!opt.agent_program || !*opt.agent_program)
        opt.agent_program = GNUPG_DEFAULT_AGENT;
      if ( !(pgmname = strrchr (opt.agent_program, '/')))
        pgmname = opt.agent_program;
      else
        pgmname++;

      argv[0] = pgmname;
      argv[1] = "--server";
      argv[2] = NULL;

      i=0;
      if (log_get_fd () != -1)
        no_close_list[i++] = log_get_fd ();
      no_close_list[i++] = fileno (stderr);
      no_close_list[i] = -1;

      /* connect to the agent and perform initial handshaking */
      rc = assuan_pipe_connect (&ctx, opt.agent_program, (char**)argv,
                                no_close_list);
    }
  else
    {
      int prot;
      int pid;

      infostr = xstrdup (infostr);
      if ( !(p = strchr (infostr, ':')) || p == infostr)
        {
          log_error (_("malformed GPG_AGENT_INFO environment variable\n"));
          xfree (infostr);
          force_pipe_server = 1;
          return start_agent ();
        }
      *p++ = 0;
      pid = atoi (p);
      while (*p && *p != ':')
        p++;
      prot = *p? atoi (p+1) : 0;
      if (prot != 1)
        {
          log_error (_("gpg-agent protocol version %d is not supported\n"),
                     prot);
          xfree (infostr);
          force_pipe_server = 1;
          return start_agent ();
        }

      rc = assuan_socket_connect (&ctx, infostr, pid);
      xfree (infostr);
      if (rc == ASSUAN_Connect_Failed)
        {
          log_error (_("can't connect to the agent - trying fall back\n"));
          force_pipe_server = 1;
          return start_agent ();
        }
    }

  if (rc)
    {
      log_error ("can't connect to the agent: %s\n", assuan_strerror (rc));
      return gpg_error (GPG_ERR_NO_AGENT);
    }
  agent_ctx = ctx;

  if (DBG_ASSUAN)
    log_debug ("connection to agent established\n");

  rc = assuan_transact (agent_ctx, "RESET", NULL, NULL, NULL, NULL, NULL, NULL);
  if (rc)
    return map_assuan_err (rc);

  dft_display = getenv ("DISPLAY");
  if (opt.display || dft_display)
    {
      char *optstr;
      if (asprintf (&optstr, "OPTION display=%s",
		    opt.display ? opt.display : dft_display) < 0)
	return gpg_error_from_errno (errno);
      rc = assuan_transact (agent_ctx, optstr, NULL, NULL, NULL, NULL, NULL,
			    NULL);
      free (optstr);
      if (rc)
	return map_assuan_err (rc);
    }
  if (!opt.ttyname)
    {
      dft_ttyname = getenv ("GPG_TTY");
      if ((!dft_ttyname || !*dft_ttyname) && ttyname (0))
        dft_ttyname = ttyname (0);
    }
  if (opt.ttyname || dft_ttyname)
    {
      char *optstr;
      if (asprintf (&optstr, "OPTION ttyname=%s",
		    opt.ttyname ? opt.ttyname : dft_ttyname) < 0)
	return gpg_error_from_errno (errno);
      rc = assuan_transact (agent_ctx, optstr, NULL, NULL, NULL, NULL, NULL,
			    NULL);
      free (optstr);
      if (rc)
	return map_assuan_err (rc);
    }
  dft_ttytype = getenv ("TERM");
  if (opt.ttytype || (dft_ttyname && dft_ttytype))
    {
      char *optstr;
      if (asprintf (&optstr, "OPTION ttytype=%s",
		    opt.ttyname ? opt.ttytype : dft_ttytype) < 0)
	return gpg_error_from_errno (errno);
      rc = assuan_transact (agent_ctx, optstr, NULL, NULL, NULL, NULL, NULL,
			    NULL);
      free (optstr);
      if (rc)
	return map_assuan_err (rc);
    }
#if defined(HAVE_SETLOCALE) && defined(LC_CTYPE)
  old_lc = setlocale (LC_CTYPE, NULL);
  if (old_lc)
    {
      old_lc = strdup (old_lc);
      if (!old_lc)
        return gpg_error_from_errno (errno);

    }
  dft_lc = setlocale (LC_CTYPE, "");
#endif
  if (opt.lc_ctype || (dft_ttyname && dft_lc))
    {
      char *optstr;
      if (asprintf (&optstr, "OPTION lc-ctype=%s",
		    opt.lc_ctype ? opt.lc_ctype : dft_lc) < 0)
	rc = gpg_error_from_errno (errno);
      else
	{
	  rc = assuan_transact (agent_ctx, optstr, NULL, NULL, NULL, NULL, NULL,
				NULL);
	  free (optstr);
	  if (rc)
	    rc = map_assuan_err (rc);
	}
    }
#if defined(HAVE_SETLOCALE) && defined(LC_CTYPE)
  if (old_lc)
    {
      setlocale (LC_CTYPE, old_lc);
      free (old_lc);
    }
#endif
  if (rc)
    return rc;
#if defined(HAVE_SETLOCALE) && defined(LC_MESSAGES)
  old_lc = setlocale (LC_MESSAGES, NULL);
  if (old_lc)
    {
      old_lc = strdup (old_lc);
      if (!old_lc)
        return gpg_error_from_errno (errno);
    }
  dft_lc = setlocale (LC_MESSAGES, "");
#endif
  if (opt.lc_messages || (dft_ttyname && dft_lc))
    {
      char *optstr;
      if (asprintf (&optstr, "OPTION lc-messages=%s",
		    opt.lc_messages ? opt.lc_messages : dft_lc) < 0)
	rc = gpg_error_from_errno (errno);
      else
	{
	  rc = assuan_transact (agent_ctx, optstr, NULL, NULL, NULL, NULL, NULL,
				NULL);
	  free (optstr);
	  if (rc)
	    rc = map_assuan_err (rc);
	}
    }
#if defined(HAVE_SETLOCALE) && defined(LC_MESSAGES)
  if (old_lc)
    {
      setlocale (LC_MESSAGES, old_lc);
      free (old_lc);
    }
#endif

  return rc;
}


static AssuanError
membuf_data_cb (void *opaque, const void *buffer, size_t length)
{
  membuf_t *data = opaque;

  if (buffer)
    put_membuf (data, buffer, length);
  return 0;
}
  


#if 0
/* Handle a KEYPARMS inquiry.  Note, we only send the data,
   assuan_transact takes care of flushing and writing the end */
static AssuanError
inq_genkey_parms (void *opaque, const char *keyword)
{
  struct genkey_parm_s *parm = opaque; 
  AssuanError rc;

  rc = assuan_send_data (parm->ctx, parm->sexp, parm->sexplen);
  return rc; 
}



/* Call the agent to generate a new key */
int
agent_genkey (KsbaConstSexp keyparms, KsbaSexp *r_pubkey)
{
  int rc;
  struct genkey_parm_s gk_parm;
  membuf_t data;
  size_t len;
  char *buf;

  *r_pubkey = NULL;
  rc = start_agent ();
  if (rc)
    return rc;

  rc = assuan_transact (agent_ctx, "RESET", NULL, NULL,
                        NULL, NULL, NULL, NULL);
  if (rc)
    return map_assuan_err (rc);

  init_membuf (&data, 1024);
  gk_parm.ctx = agent_ctx;
  gk_parm.sexp = keyparms;
  gk_parm.sexplen = gcry_sexp_canon_len (keyparms, 0, NULL, NULL);
  if (!gk_parm.sexplen)
    return gpg_error (GPG_ERR_INV_VALUE);
  rc = assuan_transact (agent_ctx, "GENKEY",
                        membuf_data_cb, &data, 
                        inq_genkey_parms, &gk_parm, NULL, NULL);
  if (rc)
    {
      xfree (get_membuf (&data, &len));
      return map_assuan_err (rc);
    }
  buf = get_membuf (&data, &len);
  if (!buf)
    return gpg_error (GPG_ERR_ENOMEM);
  if (!gcry_sexp_canon_len (buf, len, NULL, NULL))
    {
      xfree (buf);
      return gpg_error (GPG_ERR_INV_SEXP);
    }
  *r_pubkey = buf;
  return 0;
}
#endif /*0*/



/* Ask the agent whether the corresponding secret key is available for
   the given keygrip. */
int
agent_havekey (const char *hexkeygrip)
{
  int rc;
  char line[ASSUAN_LINELENGTH];

  rc = start_agent ();
  if (rc)
    return rc;

  if (!hexkeygrip || strlen (hexkeygrip) != 40)
    return gpg_error (GPG_ERR_INV_VALUE);

  snprintf (line, DIM(line)-1, "HAVEKEY %s", hexkeygrip);
  line[DIM(line)-1] = 0;

  rc = assuan_transact (agent_ctx, line, NULL, NULL, NULL, NULL, NULL, NULL);
  return map_assuan_err (rc);
}


/* Ask the agent to change the passphrase of the key identified by
   HEXKEYGRIP. */
int
agent_passwd (const char *hexkeygrip)
{
  int rc;
  char line[ASSUAN_LINELENGTH];

  rc = start_agent ();
  if (rc)
    return rc;

  if (!hexkeygrip || strlen (hexkeygrip) != 40)
    return gpg_error (GPG_ERR_INV_VALUE);

  snprintf (line, DIM(line)-1, "PASSWD %s", hexkeygrip);
  line[DIM(line)-1] = 0;

  rc = assuan_transact (agent_ctx, line, NULL, NULL, NULL, NULL, NULL, NULL);
  return map_assuan_err (rc);
}