/* gpgme.c - GnuPG Made Easy.
   Copyright (C) 2000 Werner Koch (dd9jn)
   Copyright (C) 2001, 2002, 2003, 2004, 2005, 2007, 2012,
                 2014, 2015 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 <http://www.gnu.org/licenses/>.
 */

#if HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#ifdef HAVE_LOCALE_H
#include <locale.h>
#endif

#include "util.h"
#include "context.h"
#include "ops.h"
#include "wait.h"
#include "debug.h"
#include "priv-io.h"
#include "sys-util.h"


/* The default locale.  */
DEFINE_STATIC_LOCK (def_lc_lock);
static char *def_lc_ctype;
static char *def_lc_messages;


gpgme_error_t _gpgme_selftest = GPG_ERR_NOT_OPERATIONAL;

/* Protects all reference counters in result structures.  All other
   accesses to a result structure are read only.  */
DEFINE_STATIC_LOCK (result_ref_lock);


/* Set the global flag NAME to VALUE.  Return 0 on success.  Note that
   this function does not use gpgme_error and thus a non-zero return
   value merely means "error".  Certain flags may be set before
   gpgme_check_version is called.  See the manual for a description of
   supported flags.  The caller must assure that this function is
   called only by one thread at a time.  */
int
gpgme_set_global_flag (const char *name, const char *value)
{
  if (!name || !value)
    return -1;
  else if (!strcmp (name, "debug"))
    return _gpgme_debug_set_debug_envvar (value);
  else if (!strcmp (name, "disable-gpgconf"))
    {
      _gpgme_dirinfo_disable_gpgconf ();
      return 0;
    }
  else if (!strcmp (name, "gpgconf-name"))
    return _gpgme_set_default_gpgconf_name (value);
  else if (!strcmp (name, "gpg-name"))
    return _gpgme_set_default_gpg_name (value);
  else if (!strcmp (name, "w32-inst-dir"))
    return _gpgme_set_override_inst_dir (value);
  else
    return -1;
}


/* Set the flag NAME for CTX to VALUE.  The supported flags are:
 *
 * - full-status :: With a value of "1" the status callback set by
 *                  gpgme_set_status_cb returns all status lines
 *                  except for PROGRESS lines.  With the default of
 *                  "0" the status callback is only called in certain
 *                  situations.
 */
gpgme_error_t
gpgme_set_ctx_flag (gpgme_ctx_t ctx, const char *name, const char *value)
{
  if (!ctx || !name || !value)
    return gpg_error (GPG_ERR_INV_VALUE);
  else if (!strcmp (name, "full-status"))
    {
      ctx->full_status = *value? !!atoi (value) : 0;
    }
  else
    return gpg_error (GPG_ERR_UNKNOWN_NAME);

  return 0;
}



/* Create a new context as an environment for GPGME crypto
   operations.  */
gpgme_error_t
gpgme_new (gpgme_ctx_t *r_ctx)
{
  gpgme_error_t err;
  gpgme_ctx_t ctx;
  TRACE_BEG (DEBUG_CTX, "gpgme_new", r_ctx);

  if (_gpgme_selftest)
    return TRACE_ERR (_gpgme_selftest);

  if (!r_ctx)
    return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));

  ctx = calloc (1, sizeof *ctx);
  if (!ctx)
    return TRACE_ERR (gpg_error_from_syserror ());

  INIT_LOCK (ctx->lock);

  err = _gpgme_engine_info_copy (&ctx->engine_info);
  if (!err && !ctx->engine_info)
    err = gpg_error (GPG_ERR_NO_ENGINE);
  if (err)
    {
      free (ctx);
      return TRACE_ERR (err);
    }

  ctx->keylist_mode = GPGME_KEYLIST_MODE_LOCAL;
  ctx->include_certs = GPGME_INCLUDE_CERTS_DEFAULT;
  ctx->protocol = GPGME_PROTOCOL_OpenPGP;
  ctx->sub_protocol = GPGME_PROTOCOL_DEFAULT;
  _gpgme_fd_table_init (&ctx->fdt);

  LOCK (def_lc_lock);
  if (def_lc_ctype)
    {
      ctx->lc_ctype = strdup (def_lc_ctype);
      if (!ctx->lc_ctype)
	{
          int saved_err = gpg_error_from_syserror ();
	  UNLOCK (def_lc_lock);
	  _gpgme_engine_info_release (ctx->engine_info);
	  free (ctx);
	  return TRACE_ERR (saved_err);
	}
    }
  else
    def_lc_ctype = NULL;

  if (def_lc_messages)
    {
      ctx->lc_messages = strdup (def_lc_messages);
      if (!ctx->lc_messages)
	{
          int saved_err = gpg_error_from_syserror ();
	  UNLOCK (def_lc_lock);
	  if (ctx->lc_ctype)
	    free (ctx->lc_ctype);
	  _gpgme_engine_info_release (ctx->engine_info);
	  free (ctx);
	  return TRACE_ERR (saved_err);
	}
    }
  else
    def_lc_messages = NULL;
  UNLOCK (def_lc_lock);

  *r_ctx = ctx;

  return TRACE_SUC1 ("ctx=%p", ctx);
}


gpgme_error_t
_gpgme_cancel_with_err (gpgme_ctx_t ctx, gpg_error_t ctx_err,
			gpg_error_t op_err)
{
  gpgme_error_t err;
  struct gpgme_io_event_done_data data;

  TRACE_BEG2 (DEBUG_CTX, "_gpgme_cancel_with_err", ctx, "ctx_err=%i, op_err=%i",
	      ctx_err, op_err);

  if (ctx_err)
    {
      err = _gpgme_engine_cancel (ctx->engine);
      if (err)
	return TRACE_ERR (err);
    }
  else
    {
      err = _gpgme_engine_cancel_op (ctx->engine);
      if (err)
	return TRACE_ERR (err);
    }

  data.err = ctx_err;
  data.op_err = op_err;

  _gpgme_engine_io_event (ctx->engine, GPGME_EVENT_DONE, &data);

  return TRACE_ERR (0);
}


/* Cancel a pending asynchronous operation.  */
gpgme_error_t
gpgme_cancel (gpgme_ctx_t ctx)
{
  gpg_error_t err;

  TRACE_BEG (DEBUG_CTX, "gpgme_cancel", ctx);

  if (!ctx)
    return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));

  err = _gpgme_cancel_with_err (ctx, gpg_error (GPG_ERR_CANCELED), 0);

  return TRACE_ERR (err);
}


/* Cancel a pending operation asynchronously.  */
gpgme_error_t
gpgme_cancel_async (gpgme_ctx_t ctx)
{
  TRACE_BEG (DEBUG_CTX, "gpgme_cancel_async", ctx);

  if (!ctx)
    return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));

  LOCK (ctx->lock);
  ctx->canceled = 1;
  UNLOCK (ctx->lock);

  return TRACE_ERR (0);
}


/* Release all resources associated with the given context.  */
void
gpgme_release (gpgme_ctx_t ctx)
{
  TRACE (DEBUG_CTX, "gpgme_release", ctx);

  if (!ctx)
    return;

  _gpgme_engine_release (ctx->engine);
  ctx->engine = NULL;
  _gpgme_fd_table_deinit (&ctx->fdt);
  _gpgme_release_result (ctx);
  _gpgme_signers_clear (ctx);
  _gpgme_sig_notation_clear (ctx);
  if (ctx->signers)
    free (ctx->signers);
  if (ctx->lc_ctype)
    free (ctx->lc_ctype);
  if (ctx->lc_messages)
    free (ctx->lc_messages);
  _gpgme_engine_info_release (ctx->engine_info);
  ctx->engine_info = NULL;
  DESTROY_LOCK (ctx->lock);
  free (ctx);
}


void
gpgme_result_ref (void *result)
{
  struct ctx_op_data *data;

  if (! result)
    return;

  data = (void*)((char*)result - sizeof (struct ctx_op_data));

  assert (data->magic == CTX_OP_DATA_MAGIC);

  LOCK (result_ref_lock);
  data->references++;
  UNLOCK (result_ref_lock);
}


void
gpgme_result_unref (void *result)
{
  struct ctx_op_data *data;

  if (! result)
    return;

  data = (void*)((char*)result - sizeof (struct ctx_op_data));

  assert (data->magic == CTX_OP_DATA_MAGIC);

  LOCK (result_ref_lock);
  if (--data->references)
    {
      UNLOCK (result_ref_lock);
      return;
    }
  UNLOCK (result_ref_lock);

  if (data->cleanup)
    (*data->cleanup) (data->hook);
  free (data);
}


void
_gpgme_release_result (gpgme_ctx_t ctx)
{
  struct ctx_op_data *data = ctx->op_data;

  while (data)
    {
      struct ctx_op_data *next_data = data->next;
      data->next = NULL;
      gpgme_result_unref (data->hook);
      data = next_data;
    }
  ctx->op_data = NULL;
}


gpgme_error_t
gpgme_set_protocol (gpgme_ctx_t ctx, gpgme_protocol_t protocol)
{
  TRACE_BEG2 (DEBUG_CTX, "gpgme_set_protocol", ctx, "protocol=%i (%s)",
	      protocol, gpgme_get_protocol_name (protocol)
	      ? gpgme_get_protocol_name (protocol) : "invalid");

  if (protocol != GPGME_PROTOCOL_OpenPGP
      && protocol != GPGME_PROTOCOL_CMS
      && protocol != GPGME_PROTOCOL_GPGCONF
      && protocol != GPGME_PROTOCOL_ASSUAN
      && protocol != GPGME_PROTOCOL_G13
      && protocol != GPGME_PROTOCOL_UISERVER
      && protocol != GPGME_PROTOCOL_SPAWN)
    return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));

  if (!ctx)
    return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));

  if (ctx->protocol != protocol)
    {
      /* Shut down the engine when switching protocols.  */
      if (ctx->engine)
	{
	  TRACE_LOG1 ("releasing ctx->engine=%p", ctx->engine);
	  _gpgme_engine_release (ctx->engine);
	  ctx->engine = NULL;
	}

      ctx->protocol = protocol;
    }
  return TRACE_ERR (0);
}


gpgme_protocol_t
gpgme_get_protocol (gpgme_ctx_t ctx)
{
  TRACE2 (DEBUG_CTX, "gpgme_get_protocol", ctx,
	  "ctx->protocol=%i (%s)", ctx->protocol,
	  gpgme_get_protocol_name (ctx->protocol)
	  ? gpgme_get_protocol_name (ctx->protocol) : "invalid");

  return ctx->protocol;
}


gpgme_error_t
gpgme_set_sub_protocol (gpgme_ctx_t ctx, gpgme_protocol_t protocol)
{
  TRACE2 (DEBUG_CTX, "gpgme_set_sub_protocol", ctx, "protocol=%i (%s)",
	  protocol, gpgme_get_protocol_name (protocol)
	  ? gpgme_get_protocol_name (protocol) : "invalid");

  if (!ctx)
    return gpg_error (GPG_ERR_INV_VALUE);

  ctx->sub_protocol = protocol;
  return 0;
}


gpgme_protocol_t
gpgme_get_sub_protocol (gpgme_ctx_t ctx)
{
  TRACE2 (DEBUG_CTX, "gpgme_get_sub_protocol", ctx,
	  "ctx->sub_protocol=%i (%s)", ctx->sub_protocol,
	  gpgme_get_protocol_name (ctx->sub_protocol)
	  ? gpgme_get_protocol_name (ctx->sub_protocol) : "invalid");

  return ctx->sub_protocol;
}


const char *
gpgme_get_protocol_name (gpgme_protocol_t protocol)
{
  switch (protocol)
    {
    case GPGME_PROTOCOL_OpenPGP:
      return "OpenPGP";

    case GPGME_PROTOCOL_CMS:
      return "CMS";

    case GPGME_PROTOCOL_GPGCONF:
      return "GPGCONF";

    case GPGME_PROTOCOL_ASSUAN:
      return "Assuan";

    case GPGME_PROTOCOL_G13:
      return "G13";

    case GPGME_PROTOCOL_UISERVER:
      return "UIServer";

    case GPGME_PROTOCOL_SPAWN:
      return "Spawn";

    case GPGME_PROTOCOL_DEFAULT:
      return "default";

    case GPGME_PROTOCOL_UNKNOWN:
      return "unknown";

    default:
      return NULL;
    }
}

/* Enable or disable the use of an ascii armor for all output.  */
void
gpgme_set_armor (gpgme_ctx_t ctx, int use_armor)
{
  TRACE2 (DEBUG_CTX, "gpgme_set_armor", ctx, "use_armor=%i (%s)",
	  use_armor, use_armor ? "yes" : "no");

  if (!ctx)
    return;

  ctx->use_armor = use_armor;
}


/* Return the state of the armor flag.  */
int
gpgme_get_armor (gpgme_ctx_t ctx)
{
  TRACE2 (DEBUG_CTX, "gpgme_get_armor", ctx, "ctx->use_armor=%i (%s)",
	  ctx->use_armor, ctx->use_armor ? "yes" : "no");
  return ctx->use_armor;
}


/* Enable or disable the use of the special textmode.  Textmode is for
  example used for the RFC2015 signatures; note that the updated RFC
  3156 mandates that the MUA does some preparations so that textmode
  is not needed anymore.  */
void
gpgme_set_textmode (gpgme_ctx_t ctx, int use_textmode)
{
  TRACE2 (DEBUG_CTX, "gpgme_set_textmode", ctx, "use_textmode=%i (%s)",
	  use_textmode, use_textmode ? "yes" : "no");

  if (!ctx)
    return;

  ctx->use_textmode = use_textmode;
}

/* Return the state of the textmode flag.  */
int
gpgme_get_textmode (gpgme_ctx_t ctx)
{
  TRACE2 (DEBUG_CTX, "gpgme_get_textmode", ctx, "ctx->use_textmode=%i (%s)",
	  ctx->use_textmode, ctx->use_textmode ? "yes" : "no");
  return ctx->use_textmode;
}


/* Enable offline mode for this context. In offline mode dirmngr
  will be disabled. */
void
gpgme_set_offline (gpgme_ctx_t ctx, int offline)
{
  TRACE2 (DEBUG_CTX, "gpgme_set_offline", ctx, "offline=%i (%s)",
          offline, offline ? "yes" : "no");

  if (!ctx)
    return;

  ctx->offline = offline;
}

/* Return the state of the offline flag.  */
int
gpgme_get_offline (gpgme_ctx_t ctx)
{
  TRACE2 (DEBUG_CTX, "gpgme_get_offline", ctx, "ctx->offline=%i (%s)",
          ctx->offline, ctx->offline ? "yes" : "no");
  return ctx->offline;
}


/* Set the number of certifications to include in an S/MIME message.
   The default is GPGME_INCLUDE_CERTS_DEFAULT.  -1 means all certs,
   and -2 means all certs except the root cert.  */
void
gpgme_set_include_certs (gpgme_ctx_t ctx, int nr_of_certs)
{
  if (!ctx)
    return;

  if (nr_of_certs == GPGME_INCLUDE_CERTS_DEFAULT)
    ctx->include_certs = GPGME_INCLUDE_CERTS_DEFAULT;
  else if (nr_of_certs < -2)
    ctx->include_certs = -2;
  else
    ctx->include_certs = nr_of_certs;

  TRACE2 (DEBUG_CTX, "gpgme_set_include_certs", ctx, "nr_of_certs=%i%s",
	  nr_of_certs, nr_of_certs == ctx->include_certs ? "" : " (-2)");
}


/* Get the number of certifications to include in an S/MIME
   message.  */
int
gpgme_get_include_certs (gpgme_ctx_t ctx)
{
  TRACE1 (DEBUG_CTX, "gpgme_get_include_certs", ctx, "ctx->include_certs=%i",
	  ctx->include_certs);
  return ctx->include_certs;
}


/* This function changes the default behaviour of the keylisting
   functions.  MODE is a bitwise-OR of the GPGME_KEYLIST_* flags.  The
   default mode is GPGME_KEYLIST_MODE_LOCAL.  */
gpgme_error_t
gpgme_set_keylist_mode (gpgme_ctx_t ctx, gpgme_keylist_mode_t mode)
{
  TRACE1 (DEBUG_CTX, "gpgme_set_keylist_mode", ctx, "keylist_mode=0x%x",
	  mode);

  if (!ctx)
    return gpg_error (GPG_ERR_INV_VALUE);

  ctx->keylist_mode = mode;
  return 0;
}

/* This function returns the default behaviour of the keylisting
   functions.  */
gpgme_keylist_mode_t
gpgme_get_keylist_mode (gpgme_ctx_t ctx)
{
  TRACE1 (DEBUG_CTX, "gpgme_get_keylist_mode", ctx,
	  "ctx->keylist_mode=0x%x", ctx->keylist_mode);
  return ctx->keylist_mode;
}


/* Set the pinentry mode for CTX to MODE. */
gpgme_error_t
gpgme_set_pinentry_mode (gpgme_ctx_t ctx, gpgme_pinentry_mode_t mode)
{
  TRACE1 (DEBUG_CTX, "gpgme_set_pinentry_mode", ctx, "pinentry_mode=%u",
	  (unsigned int)mode);

  if (!ctx)
    return gpg_error (GPG_ERR_INV_VALUE);

  switch (mode)
    {
    case GPGME_PINENTRY_MODE_DEFAULT:
    case GPGME_PINENTRY_MODE_ASK:
    case GPGME_PINENTRY_MODE_CANCEL:
    case GPGME_PINENTRY_MODE_ERROR:
    case GPGME_PINENTRY_MODE_LOOPBACK:
      break;
    default:
      return gpg_error (GPG_ERR_INV_VALUE);
    }

  ctx->pinentry_mode = mode;
  return 0;
}


/* Get the pinentry mode of CTX.  */
gpgme_pinentry_mode_t
gpgme_get_pinentry_mode (gpgme_ctx_t ctx)
{
  TRACE1 (DEBUG_CTX, "gpgme_get_pinentry_mode", ctx,
	  "ctx->pinentry_mode=%u", (unsigned int)ctx->pinentry_mode);
  return ctx->pinentry_mode;
}


/* This function sets a callback function to be used to pass a
   passphrase to gpg.  */
void
gpgme_set_passphrase_cb (gpgme_ctx_t ctx, gpgme_passphrase_cb_t cb,
			 void *cb_value)
{
  TRACE2 (DEBUG_CTX, "gpgme_set_passphrase_cb", ctx,
	  "passphrase_cb=%p/%p", cb, cb_value);

  if (!ctx)
    return;

  ctx->passphrase_cb = cb;
  ctx->passphrase_cb_value = cb_value;
}


/* This function returns the callback function to be used to pass a
   passphrase to the crypto engine.  */
void
gpgme_get_passphrase_cb (gpgme_ctx_t ctx, gpgme_passphrase_cb_t *r_cb,
			 void **r_cb_value)
{
  TRACE2 (DEBUG_CTX, "gpgme_get_passphrase_cb", ctx,
	  "ctx->passphrase_cb=%p/%p",
	  ctx->passphrase_cb, ctx->passphrase_cb_value);
  if (r_cb)
    *r_cb = ctx->passphrase_cb;
  if (r_cb_value)
    *r_cb_value = ctx->passphrase_cb_value;
}


/* This function sets a callback function to be used as a progress
   indicator.  */
void
gpgme_set_progress_cb (gpgme_ctx_t ctx, gpgme_progress_cb_t cb, void *cb_value)
{
  TRACE2 (DEBUG_CTX, "gpgme_set_progress_cb", ctx, "progress_cb=%p/%p",
	  cb, cb_value);

  if (!ctx)
    return;

  ctx->progress_cb = cb;
  ctx->progress_cb_value = cb_value;
}


/* This function returns the callback function to be used as a
   progress indicator.  */
void
gpgme_get_progress_cb (gpgme_ctx_t ctx, gpgme_progress_cb_t *r_cb,
		       void **r_cb_value)
{
  TRACE2 (DEBUG_CTX, "gpgme_get_progress_cb", ctx, "ctx->progress_cb=%p/%p",
	  ctx->progress_cb, ctx->progress_cb_value);
  if (r_cb)
    *r_cb = ctx->progress_cb;
  if (r_cb_value)
    *r_cb_value = ctx->progress_cb_value;
}


/* This function sets a callback function to be used as a status
   message forwarder.  */
void
gpgme_set_status_cb (gpgme_ctx_t ctx, gpgme_status_cb_t cb, void *cb_value)
{
  TRACE2 (DEBUG_CTX, "gpgme_set_status_cb", ctx, "status_cb=%p/%p",
	  cb, cb_value);

  if (!ctx)
    return;

  ctx->status_cb = cb;
  ctx->status_cb_value = cb_value;
}


/* This function returns the callback function to be used as a
   status message forwarder.  */
void
gpgme_get_status_cb (gpgme_ctx_t ctx, gpgme_status_cb_t *r_cb,
		       void **r_cb_value)
{
  TRACE2 (DEBUG_CTX, "gpgme_get_status_cb", ctx, "ctx->status_cb=%p/%p",
	  ctx ? ctx->status_cb : NULL, ctx ? ctx->status_cb_value : NULL);

  if (r_cb)
    *r_cb = NULL;

  if (r_cb_value)
    *r_cb_value = NULL;

  if (!ctx || !ctx->status_cb)
    return;

  if (r_cb)
    *r_cb = ctx->status_cb;
  if (r_cb_value)
    *r_cb_value = ctx->status_cb_value;
}


/* Set the I/O callback functions for CTX to IO_CBS.  */
void
gpgme_set_io_cbs (gpgme_ctx_t ctx, gpgme_io_cbs_t io_cbs)
{
  if (!ctx)
    return;

  if (io_cbs)
    {
      TRACE6 (DEBUG_CTX, "gpgme_set_io_cbs", ctx,
	      "io_cbs=%p (add=%p/%p, remove=%p, event=%p/%p",
	      io_cbs, io_cbs->add, io_cbs->add_priv, io_cbs->remove,
	      io_cbs->event, io_cbs->event_priv);
      ctx->io_cbs = *io_cbs;
    }
  else
    {
      TRACE1 (DEBUG_CTX, "gpgme_set_io_cbs", ctx,
	      "io_cbs=%p (default)", io_cbs);
      ctx->io_cbs.add = NULL;
      ctx->io_cbs.add_priv = NULL;
      ctx->io_cbs.remove = NULL;
      ctx->io_cbs.event = NULL;
      ctx->io_cbs.event_priv = NULL;
    }
}


/* This function provides access to the internal read function; it is
   normally not used.  */
gpgme_ssize_t
gpgme_io_read (int fd, void *buffer, size_t count)
{
  int ret;
  TRACE_BEG2 (DEBUG_GLOBAL, "gpgme_io_read", fd,
	      "buffer=%p, count=%u", buffer, count);

  ret = _gpgme_io_read (fd, buffer, count);

  return TRACE_SYSRES (ret);
}


/* This function provides access to the internal write function.  It
   is to be used by user callbacks to return data to gpgme.  See
   gpgme_passphrase_cb_t and gpgme_edit_cb_t.  */
gpgme_ssize_t
gpgme_io_write (int fd, const void *buffer, size_t count)
{
  int ret;
  TRACE_BEG2 (DEBUG_GLOBAL, "gpgme_io_write", fd,
	      "buffer=%p, count=%u", buffer, count);

  ret = _gpgme_io_write (fd, buffer, count);

  return TRACE_SYSRES (ret);
}

/* This function provides access to the internal write function.  It
   is to be used by user callbacks to return data to gpgme.  See
   gpgme_passphrase_cb_t and gpgme_edit_cb_t.  Note that this is a
   variant of gpgme_io_write which guarantees that all COUNT bytes are
   written or an error is return.  Returns: 0 on success or -1 on
   error and the sets errno. */
int
gpgme_io_writen (int fd, const void *buffer_arg, size_t count)
{
  const char *buffer = buffer_arg;
  int ret = 0;
  TRACE_BEG2 (DEBUG_GLOBAL, "gpgme_io_writen", fd,
	      "buffer=%p, count=%u", buffer, count);
  while (count)
    {
      ret = _gpgme_io_write (fd, buffer, count);
      if (ret < 0)
        break;
      buffer += ret;
      count -= ret;
      ret = 0;
    }
  return TRACE_SYSRES (ret);
}


/* This function returns the callback function for I/O.  */
void
gpgme_get_io_cbs (gpgme_ctx_t ctx, gpgme_io_cbs_t io_cbs)
{
  TRACE6 (DEBUG_CTX, "gpgme_get_io_cbs", ctx,
	  "io_cbs=%p, ctx->io_cbs.add=%p/%p, .remove=%p, .event=%p/%p",
	  io_cbs, io_cbs->add, io_cbs->add_priv, io_cbs->remove,
	  io_cbs->event, io_cbs->event_priv);

  *io_cbs = ctx->io_cbs;
}


/* This function sets the locale for the context CTX, or the default
   locale if CTX is a null pointer.  */
gpgme_error_t
gpgme_set_locale (gpgme_ctx_t ctx, int category, const char *value)
{
  int failed = 0;
  char *new_lc_ctype = NULL;
  char *new_lc_messages = NULL;

  TRACE_BEG2 (DEBUG_CTX, "gpgme_set_locale", ctx,
	       "category=%i, value=%s", category, value ? value : "(null)");

#define PREPARE_ONE_LOCALE(lcat, ucat)				\
  if (!failed && value						\
      && (category == LC_ALL || category == LC_ ## ucat))	\
    {								\
      new_lc_ ## lcat = strdup (value);				\
      if (!new_lc_ ## lcat)					\
        failed = 1;						\
    }

#ifdef LC_CTYPE
  PREPARE_ONE_LOCALE (ctype, CTYPE);
#endif
#ifdef LC_MESSAGES
  PREPARE_ONE_LOCALE (messages, MESSAGES);
#endif

  if (failed)
    {
      int saved_err = gpg_error_from_syserror ();

      if (new_lc_ctype)
	free (new_lc_ctype);
      if (new_lc_messages)
	free (new_lc_messages);

      return TRACE_ERR (saved_err);
    }

#define SET_ONE_LOCALE(lcat, ucat)			\
  if (category == LC_ALL || category == LC_ ## ucat)	\
    {							\
      if (ctx)						\
	{						\
	  if (ctx->lc_ ## lcat)				\
	    free (ctx->lc_ ## lcat);			\
	  ctx->lc_ ## lcat = new_lc_ ## lcat;		\
	}						\
      else						\
	{						\
	  if (def_lc_ ## lcat)				\
	    free (def_lc_ ## lcat);			\
	  def_lc_ ## lcat = new_lc_ ## lcat;		\
	}						\
    }

  if (!ctx)
    LOCK (def_lc_lock);
#ifdef LC_CTYPE
  SET_ONE_LOCALE (ctype, CTYPE);
#endif
#ifdef LC_MESSAGES
  SET_ONE_LOCALE (messages, MESSAGES);
#endif
  if (!ctx)
    UNLOCK (def_lc_lock);

  return TRACE_ERR (0);
}


/* Get the information about the configured engines.  A pointer to the
   first engine in the statically allocated linked list is returned.
   The returned data is valid until the next gpgme_ctx_set_engine_info.  */
gpgme_engine_info_t
gpgme_ctx_get_engine_info (gpgme_ctx_t ctx)
{
  TRACE1 (DEBUG_CTX, "gpgme_ctx_get_engine_info", ctx,
	  "ctx->engine_info=%p", ctx->engine_info);
  return ctx->engine_info;
}


/* Set the engine info for the context CTX, protocol PROTO, to the
   file name FILE_NAME and the home directory HOME_DIR.  */
gpgme_error_t
gpgme_ctx_set_engine_info (gpgme_ctx_t ctx, gpgme_protocol_t proto,
			   const char *file_name, const char *home_dir)
{
  gpgme_error_t err;
  TRACE_BEG4 (DEBUG_CTX, "gpgme_ctx_set_engine_info", ctx,
	      "protocol=%i (%s), file_name=%s, home_dir=%s",
	      proto, gpgme_get_protocol_name (proto)
	      ? gpgme_get_protocol_name (proto) : "unknown",
	      file_name ? file_name : "(default)",
	      home_dir ? home_dir : "(default)");

  if (!ctx)
    return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));

  /* Shut down the engine when changing engine info.  */
  if (ctx->engine)
    {
      TRACE_LOG1 ("releasing ctx->engine=%p", ctx->engine);
      _gpgme_engine_release (ctx->engine);
      ctx->engine = NULL;
    }
  err = _gpgme_set_engine_info (ctx->engine_info, proto,
				file_name, home_dir);
  return TRACE_ERR (err);
}


/* Clear all notation data from the context.  */
void
_gpgme_sig_notation_clear (gpgme_ctx_t ctx)
{
  gpgme_sig_notation_t notation;

  if (!ctx)
    return;

  notation = ctx->sig_notations;
  while (notation)
    {
      gpgme_sig_notation_t next_notation = notation->next;
      _gpgme_sig_notation_free (notation);
      notation = next_notation;
    }
  ctx->sig_notations = NULL;
}

void
gpgme_sig_notation_clear (gpgme_ctx_t ctx)
{
  TRACE (DEBUG_CTX, "gpgme_sig_notation_clear", ctx);

  if (!ctx)
    return;

  _gpgme_sig_notation_clear (ctx);
}


/* Add the human-readable notation data with name NAME and value VALUE
   to the context CTX, using the flags FLAGS.  If NAME is NULL, then
   VALUE should be a policy URL.  The flag
   GPGME_SIG_NOTATION_HUMAN_READABLE is forced to be true for notation
   data, and false for policy URLs.  */
gpgme_error_t
gpgme_sig_notation_add (gpgme_ctx_t ctx, const char *name,
			const char *value, gpgme_sig_notation_flags_t flags)
{
  gpgme_error_t err;
  gpgme_sig_notation_t notation;
  gpgme_sig_notation_t *lastp;

  TRACE_BEG3 (DEBUG_CTX, "gpgme_sig_notation_add", ctx,
	      "name=%s, value=%s, flags=0x%x",
	      name ? name : "(null)", value ? value : "(null)",
	      flags);

  if (!ctx)
    return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));

  if (name)
    flags |= GPGME_SIG_NOTATION_HUMAN_READABLE;
  else
    flags &= ~GPGME_SIG_NOTATION_HUMAN_READABLE;

  err = _gpgme_sig_notation_create (&notation, name, name ? strlen (name) : 0,
				    value, value ? strlen (value) : 0, flags);
  if (err)
    return TRACE_ERR (err);

  lastp = &ctx->sig_notations;
  while (*lastp)
    lastp = &(*lastp)->next;

  *lastp = notation;
  return TRACE_ERR (0);
}


/* Get the sig notations for this context.  */
gpgme_sig_notation_t
gpgme_sig_notation_get (gpgme_ctx_t ctx)
{
  if (!ctx)
    {
      TRACE (DEBUG_CTX, "gpgme_sig_notation_get", ctx);
      return NULL;
    }
  TRACE1 (DEBUG_CTX, "gpgme_sig_notation_get", ctx,
	  "ctx->sig_notations=%p", ctx->sig_notations);

  return ctx->sig_notations;
}



/* Return a public key algorithm string made of the algorithm and size
   or the curve name.  May return NULL on error.  Caller must free the
   result using gpgme_free.  */
char *
gpgme_pubkey_algo_string (gpgme_subkey_t subkey)
{
  const char *prefix = NULL;
  char *result;

  if (!subkey)
    {
      gpg_err_set_errno (EINVAL);
      return NULL;
    }

  switch (subkey->pubkey_algo)
    {
    case GPGME_PK_RSA:
    case GPGME_PK_RSA_E:
    case GPGME_PK_RSA_S: prefix = "rsa"; break;
    case GPGME_PK_ELG_E: prefix = "elg"; break;
    case GPGME_PK_DSA:	 prefix = "dsa"; break;
    case GPGME_PK_ELG:   prefix = "xxx"; break;
    case GPGME_PK_ECC:
    case GPGME_PK_ECDH:
    case GPGME_PK_ECDSA:
    case GPGME_PK_EDDSA: prefix = "";    break;
    }

  if (prefix && *prefix)
    {
      char buffer[40];
      snprintf (buffer, sizeof buffer, "%s%u", prefix, subkey->length);
      result = strdup (buffer);
    }
  else if (prefix && subkey->curve && *subkey->curve)
    result = strdup (subkey->curve);
  else if (prefix)
    result =  strdup ("E_error");
  else
    result = strdup  ("unknown");

  return result;
}


const char *
gpgme_pubkey_algo_name (gpgme_pubkey_algo_t algo)
{
  switch (algo)
    {
    case GPGME_PK_RSA:   return "RSA";
    case GPGME_PK_RSA_E: return "RSA-E";
    case GPGME_PK_RSA_S: return "RSA-S";
    case GPGME_PK_ELG_E: return "ELG-E";
    case GPGME_PK_DSA:   return "DSA";
    case GPGME_PK_ECC:   return "ECC";
    case GPGME_PK_ELG:   return "ELG";
    case GPGME_PK_ECDSA: return "ECDSA";
    case GPGME_PK_ECDH:  return "ECDH";
    case GPGME_PK_EDDSA: return "EdDSA";
    default:             return NULL;
    }
}


const char *
gpgme_hash_algo_name (gpgme_hash_algo_t algo)
{
  switch (algo)
    {
    case GPGME_MD_MD5:
      return "MD5";

    case GPGME_MD_SHA1:
      return "SHA1";

    case GPGME_MD_RMD160:
      return "RIPEMD160";

    case GPGME_MD_MD2:
      return "MD2";

    case GPGME_MD_TIGER:
      return "TIGER192";

    case GPGME_MD_HAVAL:
      return "HAVAL";

    case GPGME_MD_SHA256:
      return "SHA256";

    case GPGME_MD_SHA384:
      return "SHA384";

    case GPGME_MD_SHA512:
      return "SHA512";

    case GPGME_MD_SHA224:
      return "SHA224";

    case GPGME_MD_MD4:
      return "MD4";

    case GPGME_MD_CRC32:
      return "CRC32";

    case GPGME_MD_CRC32_RFC1510:
      return "CRC32RFC1510";

    case GPGME_MD_CRC24_RFC2440:
      return "CRC24RFC2440";

    default:
      return NULL;
    }
}