/* passwd.c - Passphrase changing function

   Copyright (C) 2010 g10 Code GmbH

   This file is part of GPGME.

   GPGME is free software; you can redistribute it and/or modify it

   under the terms of the GNU Lesser General Public License as

   published by the Free Software Foundation; either version 2.1 of

   the License, or (at your option) any later version.

   GPGME 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

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with this program; if not, see <https://www.gnu.org/licenses/>.

 */

#if HAVE_CONFIG_H

#include <config.h>

#endif

#include <stdlib.h>

#include "gpgme.h"

#include "debug.h"

#include "context.h"

#include "ops.h"

typedef struct

{

  /* The error code from a FAILURE status line or 0.  */

  gpg_error_t failure_code;

  int success_seen;

  int error_seen;

} *op_data_t;

/* Parse an error status line and return the error code.  */

static gpgme_error_t

parse_error (char *args)

{

  gpgme_error_t err;

  char *where = strchr (args, ' ');

  char *which;

  if (where)

    {

      *where = '\0';

      which = where + 1;

      where = strchr (which, ' ');

      if (where)

	*where = '\0';

      where = args;

    }

  else

    return trace_gpg_error (GPG_ERR_INV_ENGINE);

  err = atoi (which);

  if (!strcmp (where, "keyedit.passwd"))

    return err;

  return 0;

}

static gpgme_error_t

passwd_status_handler (void *priv, gpgme_status_code_t code, char *args)

{

  gpgme_ctx_t ctx = (gpgme_ctx_t) priv;

  gpgme_error_t err;

  void *hook;

  op_data_t opd;

  err = _gpgme_op_data_lookup (ctx, OPDATA_PASSWD, &hook, -1, NULL);

  opd = hook;

  if (err)

    return err;

  switch (code)

    {

    case GPGME_STATUS_ERROR:

      err = parse_error (args);

      if (err)

        opd->error_seen = 1;

      break;

    case GPGME_STATUS_SUCCESS:

      opd->success_seen = 1;

      break;

    case GPGME_STATUS_FAILURE:

      opd->failure_code = _gpgme_parse_failure (args);

      break;

    case GPGME_STATUS_EOF:

      /* In case the OpenPGP engine does not properly implement the

         passwd command we won't get a success status back and thus we

         conclude that this operation is not supported.  This is for

         example the case for GnuPG < 2.0.16.  Note that this test is

         obsolete for assuan based engines because they will properly

         return an error for an unknown command.  */

      if (ctx->protocol == GPGME_PROTOCOL_OpenPGP

          && !opd->error_seen && !opd->success_seen)

        err = gpg_error (GPG_ERR_NOT_SUPPORTED);

      else if (opd->failure_code)

        err = opd->failure_code;

      break;

    default:

      break;

    }

  return err;

}

static gpgme_error_t

passwd_start (gpgme_ctx_t ctx, int synchronous, gpgme_key_t key,

              unsigned int flags)

{

  gpgme_error_t err;

  void *hook;

  op_data_t opd;

  if (!key)

    return gpg_error (GPG_ERR_INV_VALUE);

  if (flags)

    return gpg_error (GPG_ERR_INV_FLAG);

  err = _gpgme_op_reset (ctx, synchronous);

  if (err)

    return err;

  err = _gpgme_op_data_lookup (ctx, OPDATA_PASSWD, &hook, sizeof (*opd), NULL);

  opd = hook;

  if (err)

    return err;

  opd->success_seen = 0;

  opd->error_seen = 0;

  _gpgme_engine_set_status_handler (ctx->engine, passwd_status_handler, ctx);

  if (ctx->passphrase_cb)

    {

      err = _gpgme_engine_set_command_handler

        (ctx->engine, _gpgme_passphrase_command_handler, ctx, NULL);

      if (err)

        return err;

    }

  return _gpgme_engine_op_passwd (ctx->engine, key, flags);

}

/* Change the passphrase for KEY.  FLAGS is reserved for future use

   and must be passed as 0.  The engine is expected to present a user

   interface to enter the old and the new passphrase.  This is the

   asynchronous variant.

   Note that if ever the need arises to supply a passphrase we can do

   this with a flag value and the passphrase callback feature.  */

gpgme_error_t

gpgme_op_passwd_start (gpgme_ctx_t ctx, gpgme_key_t key, unsigned int flags)

{

  gpg_error_t err;

  TRACE_BEG2 (DEBUG_CTX, "gpgme_op_passwd_start", ctx,

	      "key=%p, flags=0x%x", key, flags);

  if (!ctx)

    return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));

  err = passwd_start (ctx, 0, key, flags);

  return TRACE_ERR (err);

}

/* Change the passphrase for KEY.  FLAGS is reserved for future use

   and must be passed as 0.  This is the synchronous variant.  */

gpgme_error_t

gpgme_op_passwd (gpgme_ctx_t ctx, gpgme_key_t key, unsigned int flags)

{

  gpgme_error_t err;

  TRACE_BEG2 (DEBUG_CTX, "gpgme_op_passwd", ctx,

	      "key=%p, flags=0x%x", key, flags);

  if (!ctx)

    return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));

  err = passwd_start (ctx, 1, key, flags);

  if (!err)

    err = _gpgme_wait_one (ctx);

  return TRACE_ERR (err);

}