githubmirror/libassuan

src/client.c
335 строк9 KB
Werner Koch
Make assuan_transact more robust against inquiry errors.
07 фев 2013, 23:42
07 фев 2013, 23:42f17039b
/* client.c - Functions common to all clients.
   Copyright (C) 2009 Free Software Foundation, Inc.

   This file is part of Assuan.

   Assuan 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.

   Assuan 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/>.
 */


#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdlib.h>

#include "assuan-defs.h"
#include "debug.h"

#define xtoi_1(p)   (*(p) <= '9'? (*(p)- '0'): \
                     *(p) <= 'F'? (*(p)-'A'+10):(*(p)-'a'+10))
#define xtoi_2(p)   ((xtoi_1(p) * 16) + xtoi_1((p)+1))


void
_assuan_client_finish (assuan_context_t ctx)
{
  if (ctx->inbound.fd != ASSUAN_INVALID_FD)
    {
      _assuan_close (ctx, ctx->inbound.fd);
      if (ctx->inbound.fd == ctx->outbound.fd)
        ctx->outbound.fd = ASSUAN_INVALID_FD;
      ctx->inbound.fd = ASSUAN_INVALID_FD;
    }
  if (ctx->outbound.fd != ASSUAN_INVALID_FD)
    {
      _assuan_close (ctx, ctx->outbound.fd);
      ctx->outbound.fd = ASSUAN_INVALID_FD;
    }
  if (ctx->pid != ASSUAN_INVALID_PID && ctx->pid)
    {
      _assuan_waitpid (ctx, ctx->pid, ctx->flags.no_waitpid, NULL, 0);
      ctx->pid = ASSUAN_INVALID_PID;
    }

  _assuan_uds_deinit (ctx);
}


/* Disconnect and release the context CTX.  */
void
_assuan_client_release (assuan_context_t ctx)
{
  assuan_write_line (ctx, "BYE");

  _assuan_client_finish (ctx);
}


/* This function also does deescaping for data lines.  */
gpg_error_t
assuan_client_read_response (assuan_context_t ctx,
			     char **line_r, int *linelen_r)
{
  gpg_error_t rc;
  char *line = NULL;
  int linelen = 0;

  *line_r = NULL;
  *linelen_r = 0;

  do
    {
      do
	{
	  rc = _assuan_read_line (ctx);
	}
      while (_assuan_error_is_eagain (ctx, rc));
      if (rc)
        return rc;
      line = ctx->inbound.line;
      linelen = ctx->inbound.linelen;
    }
  while (!linelen);

  /* For data lines, we deescape immediately.  The user will never
     have to worry about it.  */
  if (linelen >= 1 && line[0] == 'D' && line[1] == ' ')
    {
      char *s, *d;
      for (s=d=line; linelen; linelen--)
	{
	  if (*s == '%' && linelen > 2)
	    { /* handle escaping */
	      s++;
	      *d++ = xtoi_2 (s);
	      s += 2;
	      linelen -= 2;
	    }
	  else
	    *d++ = *s++;
	}
      *d = 0; /* add a hidden string terminator */

      linelen = d - line;
      ctx->inbound.linelen = linelen;
    }

  *line_r = line;
  *linelen_r = linelen;

  return 0;
}


gpg_error_t
assuan_client_parse_response (assuan_context_t ctx, char *line, int linelen,
			      assuan_response_t *response, int *off)
{
  *response = ASSUAN_RESPONSE_ERROR;
  *off = 0;

  if (linelen >= 1
      && line[0] == 'D' && line[1] == ' ')
    {
      *response = ASSUAN_RESPONSE_DATA; /* data line */
      *off = 2;
    }
  else if (linelen >= 1
           && line[0] == 'S'
           && (line[1] == '\0' || line[1] == ' '))
    {
      *response = ASSUAN_RESPONSE_STATUS;
      *off = 1;
      while (line[*off] == ' ')
        ++*off;
    }
  else if (linelen >= 2
           && line[0] == 'O' && line[1] == 'K'
           && (line[2] == '\0' || line[2] == ' '))
    {
      *response = ASSUAN_RESPONSE_OK;
      *off = 2;
      while (line[*off] == ' ')
        ++*off;
    }
  else if (linelen >= 3
           && line[0] == 'E' && line[1] == 'R' && line[2] == 'R'
           && (line[3] == '\0' || line[3] == ' '))
    {
      *response = ASSUAN_RESPONSE_ERROR;
      *off = 3;
      while (line[*off] == ' ')
        ++*off;
    }
  else if (linelen >= 7
           && line[0] == 'I' && line[1] == 'N' && line[2] == 'Q'
           && line[3] == 'U' && line[4] == 'I' && line[5] == 'R'
           && line[6] == 'E'
           && (line[7] == '\0' || line[7] == ' '))
    {
      *response = ASSUAN_RESPONSE_INQUIRE;
      *off = 7;
      while (line[*off] == ' ')
        ++*off;
    }
  else if (linelen >= 3
           && line[0] == 'E' && line[1] == 'N' && line[2] == 'D'
           && (line[3] == '\0' || line[3] == ' '))
    {
      *response = ASSUAN_RESPONSE_END;
      *off = 3;
    }
  else if (linelen >= 1 && line[0] == '#')
    {
      *response = ASSUAN_RESPONSE_COMMENT;
      *off = 1;
    }
  else
    return _assuan_error (ctx, GPG_ERR_ASS_INV_RESPONSE);

  return 0;
}


gpg_error_t
_assuan_read_from_server (assuan_context_t ctx, assuan_response_t *response,
			  int *off, int convey_comments)
{
  gpg_error_t rc;
  char *line;
  int linelen;

  do
    {
      *response = ASSUAN_RESPONSE_ERROR;
      *off = 0;
      rc = assuan_client_read_response (ctx, &line, &linelen);
      if (!rc)
        rc = assuan_client_parse_response (ctx, line, linelen, response, off);
    }
  while (!rc && *response == ASSUAN_RESPONSE_COMMENT && !convey_comments);

  return rc;
}


/**
 * assuan_transact:
 * @ctx: The Assuan context
 * @command: Command line to be send to the server
 * @data_cb: Callback function for data lines
 * @data_cb_arg: first argument passed to @data_cb
 * @inquire_cb: Callback function for a inquire response
 * @inquire_cb_arg: first argument passed to @inquire_cb
 * @status_cb: Callback function for a status response
 * @status_cb_arg: first argument passed to @status_cb
 *
 * FIXME: Write documentation
 *
 * Return value: 0 on success or an error code.  The error code may be
 * the one one returned by the server via error lines or from the
 * callback functions.  Take care:  If a callback returns an error
 * this function returns immediately with this error.
 **/
gpg_error_t
assuan_transact (assuan_context_t ctx,
                 const char *command,
                 gpg_error_t (*data_cb)(void *, const void *, size_t),
                 void *data_cb_arg,
                 gpg_error_t (*inquire_cb)(void*, const char *),
                 void *inquire_cb_arg,
                 gpg_error_t (*status_cb)(void*, const char *),
                 void *status_cb_arg)
{
  gpg_error_t rc;
  assuan_response_t response;
  int off;
  char *line;
  int linelen;

  rc = assuan_write_line (ctx, command);
  if (rc)
    return rc;

  if (*command == '#' || !*command)
    return 0; /* Don't expect a response for a comment line.  */

 again:
  rc = _assuan_read_from_server (ctx, &response, &off,
                                 ctx->flags.convey_comments);
  if (rc)
    return rc; /* error reading from server */

  line = ctx->inbound.line + off;
  linelen = ctx->inbound.linelen - off;

  if (response == ASSUAN_RESPONSE_ERROR)
    rc = atoi (line);
  else if (response == ASSUAN_RESPONSE_DATA)
    {
      if (!data_cb)
        rc = _assuan_error (ctx, GPG_ERR_ASS_NO_DATA_CB);
      else
        {
          rc = data_cb (data_cb_arg, line, linelen);
          if (!rc)
            goto again;
        }
    }
  else if (response == ASSUAN_RESPONSE_INQUIRE)
    {
      if (!inquire_cb)
        {
          assuan_write_line (ctx, "END"); /* get out of inquire mode */
          _assuan_read_from_server (ctx, &response, &off, 0); /* dummy read */
          rc = _assuan_error (ctx, GPG_ERR_ASS_NO_INQUIRE_CB);
        }
      else
        {
          rc = inquire_cb (inquire_cb_arg, line);
          if (!rc)
            rc = assuan_send_data (ctx, NULL, 0); /* flush and send END */
          else
            { /* Flush and send CAN.  */
              /* Note that in this error case we don't want to return
                 an error code from sending the cancel.  The dummy
                 read is to remove the response from the server which
                 we are not interested in.  */
              assuan_send_data (ctx, NULL, 1);
              _assuan_read_from_server (ctx, &response, &off, 0);
            }
          if (!rc)
            goto again;
        }
    }
  else if (response == ASSUAN_RESPONSE_STATUS)
    {
      if (status_cb)
        rc = status_cb (status_cb_arg, line);
      if (!rc)
        goto again;
    }
  else if (response == ASSUAN_RESPONSE_COMMENT && ctx->flags.convey_comments)
    {
      line -= off; /* Send line with the comment marker.  */
      if (status_cb)
        rc = status_cb (status_cb_arg, line);
      if (!rc)
        goto again;
    }
  else if (response == ASSUAN_RESPONSE_END)
    {
      if (!data_cb)
        rc = _assuan_error (ctx, GPG_ERR_ASS_NO_DATA_CB);
      else
        {
          rc = data_cb (data_cb_arg, NULL, 0);
          if (!rc)
            goto again;
        }
    }

  return rc;
}