/* data-compat.c - Compatibility interfaces for data objects.

 * Copyright (C) 2002, 2003, 2004, 2007 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://gnu.org/licenses/>.

 * SPDX-License-Identifier: LGPL-2.1-or-later

 */

#if HAVE_CONFIG_H

#include <config.h>

#endif

#include <errno.h>

#ifdef HAVE_SYS_TIME_H

# include <sys/time.h>

#endif

#ifdef HAVE_SYS_STAT_H

# include <sys/stat.h>

#endif

#include <stdlib.h>

#include "data.h"

#include "util.h"

#include "debug.h"

/* Create a new data buffer filled with LENGTH bytes starting from

   OFFSET within the file FNAME or stream STREAM (exactly one must be

   non-zero).  */

gpgme_error_t

gpgme_data_new_from_filepart (gpgme_data_t *r_dh, const char *fname,

			      FILE *stream, gpgme_off_t offset, size_t length)

{

  gpgme_error_t err;

  char *buf = NULL;

  int res;

  TRACE_BEG  (DEBUG_DATA, "gpgme_data_new_from_filepart", r_dh,

	      "file_name=%s, stream=%p, offset=%lli, length=%zu",

	      fname, stream, (long long int)offset, length);

  if (stream && fname)

    return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));

  if (fname)

    stream = fopen (fname, "rb");

  if (!stream)

    return TRACE_ERR (gpg_error_from_syserror ());

#ifdef HAVE_FSEEKO

  res = fseeko (stream, offset, SEEK_SET);

#else

  /* FIXME: Check for overflow, or at least bail at compilation.  */

  res = fseek (stream, offset, SEEK_SET);

#endif

  if (res)

    {

      int saved_err = gpg_error_from_syserror ();

      if (fname)

	fclose (stream);

      return TRACE_ERR (saved_err);

    }

  buf = malloc (length);

  if (!buf)

    {

      int saved_err = gpg_error_from_syserror ();

      if (fname)

	fclose (stream);

      return TRACE_ERR (saved_err);

    }

  while (fread (buf, length, 1, stream) < 1

	 && ferror (stream) && errno == EINTR);

  if (ferror (stream))

    {

      int saved_err = gpg_error_from_syserror ();

      if (buf)

	free (buf);

      if (fname)

	fclose (stream);

      return TRACE_ERR (saved_err);

    }

  if (fname)

    fclose (stream);

  err = gpgme_data_new (r_dh);

  if (err)

    {

      if (buf)

	free (buf);

      return err;

    }

  (*r_dh)->data.mem.buffer = buf;

  (*r_dh)->data.mem.size = length;

  (*r_dh)->data.mem.length = length;

  TRACE_SUC ("r_dh=%p", *r_dh);

  return 0;

}

/* Create a new data buffer filled with the content of file FNAME.

   COPY must be non-zero (delayed reads are not supported yet).  */

gpgme_error_t

gpgme_data_new_from_file (gpgme_data_t *r_dh, const char *fname, int copy)

{

  gpgme_error_t err;

  struct stat statbuf;

  TRACE_BEG  (DEBUG_DATA, "gpgme_data_new_from_file", r_dh,

	      "file_name=%s, copy=%i (%s)", fname, copy, copy ? "yes" : "no");

  if (!fname || !copy)

    return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));

  if (stat (fname, &statbuf) < 0)

    return TRACE_ERR (gpg_error_from_syserror ());

  err = gpgme_data_new_from_filepart (r_dh, fname, NULL, 0, statbuf.st_size);

  return TRACE_ERR (err);

}

static int

gpgme_error_to_errno (gpgme_error_t err)

{

  int res = gpg_err_code_to_errno (gpg_err_code (err));

  if (!err)

    {

      switch (gpg_err_code (err))

	{

	case GPG_ERR_EOF:

	  res = 0;

	  break;

	case GPG_ERR_INV_VALUE:

	  res = EINVAL;

	  break;

	case GPG_ERR_NOT_SUPPORTED:

	  res = ENOSYS;

	  break;

	default:

	  /* FIXME: Yeah, well.  */

	  res = EINVAL;

	  break;

	}

    }

  TRACE (DEBUG_DATA, "gpgme:gpgme_error_to_errno", NULL,

	  "mapping %s <%s> to: %s", gpgme_strerror (err),

	  gpgme_strsource (err), strerror (res));

  gpg_err_set_errno (res);

  return res ? -1 : 0;

}

static gpgme_ssize_t

old_user_read (gpgme_data_t dh, void *buffer, size_t size)

{

  gpgme_error_t err;

  size_t amt;

  TRACE_BEG  (DEBUG_DATA, "gpgme:old_user_read", dh,

	      "buffer=%p, size=%zu", buffer, size);

  err = (*dh->data.old_user.cb) (dh->data.old_user.handle,

				 buffer, size, &amt;;

  if (err)

    return TRACE_SYSRES (gpgme_error_to_errno (err));

  return TRACE_SYSRES ((int)amt);

}

static gpgme_off_t

old_user_seek (gpgme_data_t dh, gpgme_off_t offset, int whence)

{

  gpgme_error_t err;

  TRACE_BEG  (DEBUG_DATA, "gpgme:old_user_seek", dh,

	      "offset=%llu, whence=%i", (long long int)offset, whence);

  if (whence != SEEK_SET || offset)

    {

      gpg_err_set_errno (EINVAL);

      return TRACE_SYSRES (-1);

    }

  err = (*dh->data.old_user.cb) (dh->data.old_user.handle, NULL, 0, NULL);

  if (err)

    return TRACE_SYSRES (gpgme_error_to_errno (err));

  return TRACE_SYSRES (0);

}

static struct _gpgme_data_cbs old_user_cbs =

  {

    old_user_read,

    NULL,

    old_user_seek,

    NULL

  };

/* Create a new data buffer which retrieves the data from the callback

   function READ_CB.  */

gpgme_error_t

gpgme_data_new_with_read_cb (gpgme_data_t *r_dh,

                             int (*read_cb) (void *, char *, size_t, size_t *),

                             void *read_cb_value)

{

  gpgme_error_t err;

  TRACE_BEG  (DEBUG_DATA, "gpgme_data_new_with_read_cb", r_dh,

	      "read_cb=%p/%p", read_cb, read_cb_value);

  err = _gpgme_data_new (r_dh, &old_user_cbs);

  if (err)

    return TRACE_ERR (err);

  (*r_dh)->data.old_user.cb = read_cb;

  (*r_dh)->data.old_user.handle = read_cb_value;

  return TRACE_ERR (0);

}