/* server.c - The G13 Assuan server
 * Copyright (C) 2009 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 3 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, see <http://www.gnu.org/licenses/>.
 */

#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <errno.h>
#include <assert.h>

#include "g13.h"
#include <assuan.h>
#include "i18n.h"
#include "keyblob.h"
#include "./server.h"
#include "./mount.h"


/* Local data for this server module.  A pointer to this is stored in
   the CTRL object of each connection.  */
struct server_local_s 
{
  /* The Assuan contect we are working on.  */
  assuan_context_t assuan_ctx;

  char *mountpoint;  /* Malloced current mountpoint.  */

};


/* Cookie definition for assuan data line output.  */
static ssize_t data_line_cookie_write (void *cookie,
                                       const void *buffer, size_t size);
static int data_line_cookie_close (void *cookie);
static es_cookie_io_functions_t data_line_cookie_functions =
  {
    NULL,
    data_line_cookie_write,
    NULL,
    data_line_cookie_close
  };


/* The filepointer for status message used in non-server mode.  */
/* static FILE *statusfp;  FIXME; */




static int command_has_option (const char *cmd, const char *cmdopt);




#define set_error(e,t) assuan_set_error (ctx, gpg_error (e), (t))




/* Skip over options.  
   Blanks after the options are also removed.  */
static char *
skip_options (const char *line)
{
  while (spacep (line))
    line++;
  while ( *line == '-' && line[1] == '-' )
    {
      while (*line && !spacep (line))
        line++;
      while (spacep (line))
        line++;
    }
  return (char*)line;
}


/* Check whether the option NAME appears in LINE.  */
static int
has_option (const char *line, const char *name)
{
  const char *s;
  int n = strlen (name);

  s = strstr (line, name);
  if (s && s >= skip_options (line))
    return 0;
  return (s && (s == line || spacep (s-1)) && (!s[n] || spacep (s+n)));
}


/* A write handler used by es_fopencookie to write Assuan data
   lines.  */
static ssize_t
data_line_cookie_write (void *cookie, const void *buffer, size_t size)
{
  assuan_context_t ctx = cookie;

  if (assuan_send_data (ctx, buffer, size))
    {
      errno = EIO;
      return -1;
    }

  return size;
}

/* A close handler used by es_fopencookie to write Assuan data
   lines.  */
static int
data_line_cookie_close (void *cookie)
{
  assuan_context_t ctx = cookie;

  if (assuan_send_data (ctx, NULL, 0))
    {
      errno = EIO;
      return -1;
    }

  return 0;
}


/* The handler for Assuan OPTION commands.  */
static gpg_error_t
option_handler (assuan_context_t ctx, const char *key, const char *value)
{
  ctrl_t ctrl = assuan_get_pointer (ctx);
  gpg_error_t err = 0;

  if (!strcmp (key, "putenv"))
    {
      /* Change the session's environment to be used for the
         Pinentry.  Valid values are:
          <NAME>            Delete envvar NAME
          <KEY>=            Set envvar NAME to the empty string
          <KEY>=<VALUE>     Set envvar NAME to VALUE
      */
      err = session_env_putenv (opt.session_env, value);
    }
  else if (!strcmp (key, "display"))
    {
      err = session_env_setenv (opt.session_env, "DISPLAY", value);
    }
  else if (!strcmp (key, "ttyname"))
    {
      err = session_env_setenv (opt.session_env, "GPG_TTY", value);
    }
  else if (!strcmp (key, "ttytype"))
    {
      err = session_env_setenv (opt.session_env, "TERM", value);
    }
  else if (!strcmp (key, "lc-ctype"))
    {
      xfree (opt.lc_ctype);
      opt.lc_ctype = xtrystrdup (value);
      if (!opt.lc_ctype)
        err = gpg_error_from_syserror ();
    }
  else if (!strcmp (key, "lc-messages"))
    {
      xfree (opt.lc_messages);
      opt.lc_messages = xtrystrdup (value);
      if (!opt.lc_messages)
        err = gpg_error_from_syserror ();
    }
  else if (!strcmp (key, "xauthority"))
    {
      err = session_env_setenv (opt.session_env, "XAUTHORITY", value);
    }
  else if (!strcmp (key, "pinentry-user-data"))
    {
      err = session_env_setenv (opt.session_env, "PINENTRY_USER_DATA", value);
    }
  else if (!strcmp (key, "enable-audit-log"))
    {
      /* This is not yet used.  */
      /* int i = *value? atoi (value) : 0; */
      /* ctrl->server_local->enable_audit_log = i; */
    }
  else if (!strcmp (key, "allow-pinentry-notify"))
    {
      ; /* We always allow it.  */
    }
  else
    err = gpg_error (GPG_ERR_UNKNOWN_OPTION);

  return err;
}


/* The handler for an Assuan RESET command.  */
static void
reset_notify (assuan_context_t ctx)
{
  ctrl_t ctrl = assuan_get_pointer (ctx);

  xfree (ctrl->server_local->mountpoint);
  ctrl->server_local->mountpoint = NULL;

  assuan_close_input_fd (ctx);
  assuan_close_output_fd (ctx);
}


/* Helper to print a message while leaving a command.  */
static gpg_error_t
leave_cmd (assuan_context_t ctx, gpg_error_t err)
{
  if (err)
    {
      const char *name = assuan_get_command_name (ctx);
      if (!name)
        name = "?";
      if (gpg_err_source (err) == GPG_ERR_SOURCE_DEFAULT)
        log_error ("command '%s' failed: %s\n", name,
                   gpg_strerror (err));
      else
        log_error ("command '%s' failed: %s <%s>\n", name,
                   gpg_strerror (err), gpg_strsource (err));
    }
  return err;
}



/* RECIPIENT <userID>

   FIXME - description. 
   All RECIPIENT commands are cumulative until a RESET or an
   successful CREATE command.
 */
static gpg_error_t
cmd_recipient (assuan_context_t ctx, char *line)
{
  ctrl_t ctrl = assuan_get_pointer (ctx);
  gpg_error_t err;

  (void)ctrl;
  err = gpg_error (GPG_ERR_NOT_IMPLEMENTED);
  /* err = gpgsm_add_to_certlist (ctrl, line, 0, */
  /*                              &ctrl->server_local->recplist, 0); */
  /* if (err) */
  /*   { */
  /*     gpgsm_status2 (ctrl, STATUS_INV_RECP, */
  /*                    get_inv_recpsgnr_code (rc), line, NULL); */
  /*   } */

  return leave_cmd (ctx, err);
}


/* SIGNER <userID>

   FIXME - description. 
 */
static gpg_error_t
cmd_signer (assuan_context_t ctx, char *line)
{
  ctrl_t ctrl = assuan_get_pointer (ctx);
  gpg_error_t err;

  (void)ctrl;

  err = gpg_error (GPG_ERR_NOT_IMPLEMENTED);
  return leave_cmd (ctx, err);
}


/* SETMOUNTPOINT [options] [<dirname>]

   Set DIRNAME as the new mount point for future operations.  
 */
static gpg_error_t
cmd_setmountpoint (assuan_context_t ctx, char *line)
{
  ctrl_t ctrl = assuan_get_pointer (ctx);
  gpg_error_t err = 0;
  char *p, *pend;
  size_t len;

  line = skip_options (line);
  for (p=line; *p && !spacep (p); p++)
    ;
  pend = p;
  while (spacep(p))
    p++;
  if (*p)
    {
      err = gpg_error (GPG_ERR_ASS_SYNTAX);
      goto leave;
    }
  *pend = 0;

  /* Unescape the line and check for embedded Nul bytes.  */
  len = percent_plus_unescape_inplace (line, 0);
  line[len] = 0;
  if (memchr (line, 0, len))
    {
      err = gpg_error (GPG_ERR_INV_NAME);
      goto leave;
    }

  xfree (ctrl->server_local->mountpoint);
  if (!len)  /* Reset mountpoint.  */
    ctrl->server_local->mountpoint = NULL;
  else
    {
      ctrl->server_local->mountpoint = xtrystrdup (line);
      if (!ctrl->server_local->mountpoint)
        err = gpg_error_from_syserror ();
    }

  if (!err)
    log_debug ("mountpoint is now `%s'\n", 
               ctrl->server_local->mountpoint
               ? ctrl->server_local->mountpoint: "[none]");

 leave:
  return leave_cmd (ctx, err);
}


/* MOUNT [options] <containername>

   Mount CONTAINERNAME onto the current mount point.  CONTAINERNAME is
   the name of a file in the g13 format and must be percent-plus
   escaped to allow for arbitrary names.  The mount poiunt must have
   been set already.


   A reason why we use a separate command for the mount point is to
   allow for longer filenames (an assuan command line is limited to
   ~1000 byte. 
 */
static gpg_error_t
cmd_mount (assuan_context_t ctx, char *line)
{
  ctrl_t ctrl = assuan_get_pointer (ctx);
  gpg_error_t err = 0;
  char *p, *pend;
  size_t len;

  line = skip_options (line);
  for (p=line; *p && !spacep (p); p++)
    ;
  pend = p;
  while (spacep(p))
    p++;
  if (*p || pend == line)
    {
      err = gpg_error (GPG_ERR_ASS_SYNTAX);
      goto leave;
    }
  *pend = 0;

  /* Unescape the line and check for embedded Nul bytes.  */
  len = percent_plus_unescape_inplace (line, 0);
  line[len] = 0;
  if (!len || memchr (line, 0, len))
    {
      err = gpg_error (GPG_ERR_INV_NAME);
      goto leave;
    }
    
  /* Perform the mount.  */
  err = g13_mount_container (ctrl, line, ctrl->server_local->mountpoint);

 leave:
  return leave_cmd (ctx, err);
}


/* GETINFO <what>

   Multipurpose function to return a variety of information.
   Supported values for WHAT are:

     version     - Return the version of the program.
     pid         - Return the process id of the server.
     cmd_has_option CMD OPT
                 - Returns OK if the command CMD implements the option OPT.

 */
static gpg_error_t
cmd_getinfo (assuan_context_t ctx, char *line)
{
  gpg_error_t err = 0;

  if (!strcmp (line, "version"))
    {
      const char *s = PACKAGE_VERSION;
      err = assuan_send_data (ctx, s, strlen (s));
    }
  else if (!strcmp (line, "pid"))
    {
      char numbuf[50];

      snprintf (numbuf, sizeof numbuf, "%lu", (unsigned long)getpid ());
      err = assuan_send_data (ctx, numbuf, strlen (numbuf));
    }
  else if (!strncmp (line, "cmd_has_option", 14)
           && (line[14] == ' ' || line[14] == '\t' || !line[14]))
    {
      char *cmd, *cmdopt;
      line += 14;
      while (*line == ' ' || *line == '\t')
        line++;
      if (!*line)
        err = gpg_error (GPG_ERR_MISSING_VALUE);
      else
        {
          cmd = line;
          while (*line && (*line != ' ' && *line != '\t'))
            line++;
          if (!*line)
            err = gpg_error (GPG_ERR_MISSING_VALUE);
          else
            {
              *line++ = 0;
              while (*line == ' ' || *line == '\t')
                line++;
              if (!*line)
                err = gpg_error (GPG_ERR_MISSING_VALUE);
              else
                {
                  cmdopt = line;
                  if (!command_has_option (cmd, cmdopt))
                    err = gpg_error (GPG_ERR_GENERAL);
                }
            }
        }
    }
  else
    err = set_error (GPG_ERR_ASS_PARAMETER, "unknown value for WHAT");

  return leave_cmd (ctx, err);
}



/* Return true if the command CMD implements the option CMDOPT.  */
static int
command_has_option (const char *cmd, const char *cmdopt)
{
  (void)cmd;
  (void)cmdopt;
      
  return 0;
}


/* Tell the Assuan library about our commands.  */
static int
register_commands (assuan_context_t ctx)
{
  static struct {
    const char *name;
    gpg_error_t (*handler)(assuan_context_t, char *line);
  } table[] =  {
    { "RECIPIENT",     cmd_recipient },
    { "SIGNER",        cmd_signer },
    { "MOUNT",         cmd_mount },
    { "SETMOUNTPOINT", cmd_setmountpoint },
    { "INPUT",         NULL }, 
    { "OUTPUT",        NULL }, 
    { "GETINFO",       cmd_getinfo },
    { NULL }
  };
  gpg_error_t err;
  int i;

  for (i=0; table[i].name; i++)
    {
      err = assuan_register_command (ctx, table[i].name, table[i].handler);
      if (err)
        return err;
    } 
  return 0;
}


/* Startup the server. DEFAULT_RECPLIST is the list of recipients as
   set from the command line or config file.  We only require those
   marked as encrypt-to. */
gpg_error_t
g13_server (ctrl_t ctrl)
{
  gpg_error_t err;
  int filedes[2];
  assuan_context_t ctx = NULL;
  static const char hello[] = ("GNU Privacy Guard's G13 server "
                               PACKAGE_VERSION " ready");

  /* We use a pipe based server so that we can work from scripts.
     assuan_init_pipe_server will automagically detect when we are
     called with a socketpair and ignore FIELDES in this case. */
  filedes[0] = 0;
  filedes[1] = 1;
  err = assuan_new (&ctx);
  if (err)
    {
      log_error ("failed to allocate an Assuan context: %s\n",
                 gpg_strerror (err));
      goto leave;
    }

  err = assuan_init_pipe_server (ctx, filedes);
  if (err)
    {
      log_error ("failed to initialize the server: %s\n", gpg_strerror (err));
      goto leave;
    }

  err = register_commands (ctx);
  if (err)
    {
      log_error ("failed to the register commands with Assuan: %s\n",
                 gpg_strerror (err));
      goto leave;
    }

  assuan_set_pointer (ctx, ctrl);

  if (opt.verbose || opt.debug)
    {
      char *tmp = NULL;
      const char *s1 = getenv ("GPG_AGENT_INFO");

      tmp = xtryasprintf ("Home: %s\n"
                          "Config: %s\n"
                          "AgentInfo: %s\n"
                          "%s",
                          opt.homedir,
                          opt.config_filename,
                          s1?s1:"[not set]",
                          hello);
      if (tmp)
        {
          assuan_set_hello_line (ctx, tmp);
          xfree (tmp);
        }
    }
  else
    assuan_set_hello_line (ctx, hello);

  assuan_register_reset_notify (ctx, reset_notify);
  assuan_register_option_handler (ctx, option_handler);

  ctrl->server_local = xtrycalloc (1, sizeof *ctrl->server_local);
  if (!ctrl->server_local)
    {
      err = gpg_error_from_syserror ();
      goto leave;
    }
  ctrl->server_local->assuan_ctx = ctx;

  if (DBG_ASSUAN)
    assuan_set_log_stream (ctx, log_get_stream ());

  while ( !(err = assuan_accept (ctx)) )
    {
      err = assuan_process (ctx);
      if (err)
        log_info ("Assuan processing failed: %s\n", gpg_strerror (err));
    }
  if (err == -1)
    err = 0;
  else
    log_info ("Assuan accept problem: %s\n", gpg_strerror (err));
  
 leave:
  if (ctrl->server_local)
    {
      xfree (ctrl->server_local);
      ctrl->server_local = NULL;
    }

  assuan_release (ctx);
  return err;
}



/* gpg_error_t */
/* gpgsm_status2 (ctrl_t ctrl, int no, ...) */
/* { */
/*   gpg_error_t err = 0; */
/*   va_list arg_ptr; */
/*   const char *text; */

/*   va_start (arg_ptr, no); */

/*   if (ctrl->no_server && ctrl->status_fd == -1) */
/*     ; /\* No status wanted. *\/ */
/*   else if (ctrl->no_server) */
/*     { */
/*       if (!statusfp) */
/*         { */
/*           if (ctrl->status_fd == 1) */
/*             statusfp = stdout; */
/*           else if (ctrl->status_fd == 2) */
/*             statusfp = stderr; */
/*           else */
/*             statusfp = fdopen (ctrl->status_fd, "w"); */
      
/*           if (!statusfp) */
/*             { */
/*               log_fatal ("can't open fd %d for status output: %s\n", */
/*                          ctrl->status_fd, strerror(errno)); */
/*             } */
/*         } */
      
/*       fputs ("[GNUPG:] ", statusfp); */
/*       fputs (get_status_string (no), statusfp); */
    
/*       while ( (text = va_arg (arg_ptr, const char*) )) */
/*         { */
/*           putc ( ' ', statusfp ); */
/*           for (; *text; text++)  */
/*             { */
/*               if (*text == '\n') */
/*                 fputs ( "\\n", statusfp ); */
/*               else if (*text == '\r') */
/*                 fputs ( "\\r", statusfp ); */
/*               else  */
/*                 putc ( *(const byte *)text,  statusfp ); */
/*             } */
/*         } */
/*       putc ('\n', statusfp); */
/*       fflush (statusfp); */
/*     } */
/*   else  */
/*     { */
/*       assuan_context_t ctx = ctrl->server_local->assuan_ctx; */
/*       char buf[950], *p; */
/*       size_t n; */

/*       p = buf;  */
/*       n = 0; */
/*       while ( (text = va_arg (arg_ptr, const char *)) ) */
/*         { */
/*           if (n) */
/*             { */
/*               *p++ = ' '; */
/*               n++; */
/*             } */
/*           for ( ; *text && n < DIM (buf)-2; n++) */
/*             *p++ = *text++; */
/*         } */
/*       *p = 0; */
/*       err = assuan_write_status (ctx, get_status_string (no), buf); */
/*     } */

/*   va_end (arg_ptr); */
/*   return err; */
/* } */

/* gpg_error_t */
/* gpgsm_status (ctrl_t ctrl, int no, const char *text) */
/* { */
/*   return gpgsm_status2 (ctrl, no, text, NULL); */
/* } */

/* gpg_error_t */
/* gpgsm_status_with_err_code (ctrl_t ctrl, int no, const char *text, */
/*                             gpg_err_code_t ec) */
/* { */
/*   char buf[30]; */

/*   sprintf (buf, "%u", (unsigned int)ec); */
/*   if (text) */
/*     return gpgsm_status2 (ctrl, no, text, buf, NULL); */
/*   else */
/*     return gpgsm_status2 (ctrl, no, buf, NULL); */
/* } */


/* Helper to notify the client about Pinentry events.  Returns an gpg
   error code. */
gpg_error_t
g13_proxy_pinentry_notify (ctrl_t ctrl, const unsigned char *line)
{
  if (!ctrl || !ctrl->server_local)
    return 0;
  return assuan_inquire (ctrl->server_local->assuan_ctx, line, NULL, NULL, 0);
}