/* version.c -  version check
 *	Copyright (C) 2000 Werner Koch (dd9jn)
 *      Copyright (C) 2001 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 General Public License as published by
 * the Free Software Foundation; either version 2 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 */

#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include "gpgme.h"
#include "context.h"
#include "rungpg.h"
#include "sema.h"
#include "util.h"
#include "key.h" /* for key_cache_init */
#include "io.h"

static const char *get_engine_info (void);


static void
do_subsystem_inits (void)
{
    static int done = 0;

    if (done)
        return;
    _gpgme_sema_subsystem_init ();
    _gpgme_key_cache_init ();
}



static const char*
parse_version_number ( const char *s, int *number )
{
    int val = 0;

    if ( *s == '0' && isdigit(s[1]) )
	return NULL; /* leading zeros are not allowed */
    for ( ; isdigit(*s); s++ ) {
	val *= 10;
	val += *s - '0';
    }
    *number = val;
    return val < 0? NULL : s;
}


static const char *
parse_version_string( const char *s, int *major, int *minor, int *micro )
{
    s = parse_version_number ( s, major );
    if ( !s || *s != '.' )
	return NULL;
    s++;
    s = parse_version_number ( s, minor );
    if ( !s || *s != '.' )
	return NULL;
    s++;
    s = parse_version_number ( s, micro );
    if ( !s )
	return NULL;
    return s; /* patchlevel */
}

const char *
_gpgme_compare_versions (const char *my_version,
			 const char *req_version)
{
  int my_major, my_minor, my_micro;
  int rq_major, rq_minor, rq_micro;
  const char *my_plvl, *rq_plvl;

  if (!req_version)
    return my_version;

  my_plvl = parse_version_string (my_version, &my_major, &my_minor, &my_micro);
  if (!my_plvl)
    return NULL;	/* Very strange: our own version is bogus.  */
  rq_plvl = parse_version_string(req_version,
				 &rq_major, &rq_minor, &rq_micro);
  if (!rq_plvl)
    return NULL;	/* Requested version string is invalid.  */

  if (my_major > rq_major
	|| (my_major == rq_major && my_minor > rq_minor)
      || (my_major == rq_major && my_minor == rq_minor 
	  && my_micro > rq_micro)
      || (my_major == rq_major && my_minor == rq_minor
	  && my_micro == rq_micro
	  && strcmp( my_plvl, rq_plvl ) >= 0))
    {
      return my_version;
    }
  return NULL;
}


/**
 * gpgme_check_version:
 * @req_version: A string with a version
 * 
 * Check that the the version of the library is at minimum the requested one
 * and return the version string; return NULL if the condition is not
 * met.  If a NULL is passed to this function, no check is done and
 * the version string is simply returned.  It is a pretty good idea to
 * run this function as soon as possible, because it also intializes 
 * some subsystems.  In a multithreaded environment if should be called
 * before the first thread is created.
 * 
 * Return value: The version string or NULL
 **/
const char *
gpgme_check_version (const char *req_version)
{
  do_subsystem_inits ();
  return _gpgme_compare_versions (VERSION, req_version);
}

/**
 * gpgme_get_engine_info:
 *  
 * Return information about the underlying crypto engine.  This is an
 * XML string with various information.  To get the version of the
 * crypto engine it should be sufficient to grep for the first
 * <literal>version</literal> tag and use it's content.  A string is
 * always returned even if the crypto engine is not installed; in this
 * case a XML string with some error information is returned.
 * 
 * Return value: A XML string with information about the crypto engine.
 **/
const char *
gpgme_get_engine_info ()
{
    do_subsystem_inits ();
    return get_engine_info ();
}

/**
 * gpgme_check_engine:
 * 
 * Check whether the installed crypto engine matches the requirement of
 * GPGME.
 *
 * Return value: 0 or an error code.
 **/
GpgmeError
gpgme_check_engine ()
{
    const char *info = gpgme_get_engine_info ();
    const char *s, *s2;

    s = strstr (info, "<version>");
    if (s) {
        s += 9;
        s2 = strchr (s, '<');
        if (s2) {
            char *ver = xtrymalloc (s2 - s + 1);
            if (!ver)
                return mk_error (Out_Of_Core);
            memcpy (ver, s, s2-s);
            ver[s2-s] = 0;
            s = _gpgme_compare_versions ( ver, NEED_GPG_VERSION );
            xfree (ver);
            if (s)
                return 0;
        }
    }
    return mk_error (Invalid_Engine);
}



#define LINELENGTH 80

char *
_gpgme_get_program_version (const char *const path)
{
  char line[LINELENGTH] = "";
  int linelen = 0;
  char *mark = NULL;
  int rp[2];
  pid_t pid;
  int nread;
  char *argv[] = {(char *) path, "--version", 0};
  struct spawn_fd_item_s pfd[] = { {0, -1}, {-1, -1} };
  struct spawn_fd_item_s cfd[] = { {0, -1}, {-1, 1 /* STDOUT_FILENO */},
				   {-1, -1} };
  int status, signal;

  if (!path)
    return NULL;

  if (_gpgme_io_pipe (rp, 1) < 0)
    return NULL;

  pfd[0].fd = rp[1];
  cfd[0].fd = rp[0];
  cfd[1].fd = rp[1];

  pid = _gpgme_io_spawn (path, argv, cfd, pfd);
  if (pid < 0)
    {
      _gpgme_io_close (rp[0]);
      _gpgme_io_close (rp[1]);
      return NULL;
    }

  do
    {
      nread = _gpgme_io_read (rp[0], &line[linelen], LINELENGTH - linelen - 1);
      if (nread > 0)
	{
	  line[linelen + nread] = '\0';
	  mark = strchr (&line[linelen], '\n');
	  if (mark)
	    {
	      *mark = '\0';
	      break;
	    }
	  linelen += nread;
	}
    }
  while (nread > 0 && linelen < LINELENGTH - 1);

  _gpgme_io_close (rp[0]);
  _gpgme_io_waitpid (pid, 1, &status, &signal);

  if (mark)
    {
      mark = strrchr (line, ' ');
      if (!mark)
	return NULL;
      return xtrystrdup (mark + 1);
    }

  return NULL;
}

static const char *
get_engine_info (void)
{
    static const char *engine_info =NULL;
    GpgmeError err = 0;
    const char *path = NULL;
    char *version;

    /* FIXME: make sure that only one instance does run */
    if (engine_info)
        return engine_info;

    path = _gpgme_get_gpg_path ();
    if (!path)
      {
	engine_info = "<GnupgInfo>\n"
	  "  <error>Not supported</error>\n"
	  "</GnupgInfo>\n";
	goto leave;
      }
    version = _gpgme_get_program_version (path);

    if (version) {
        const char *fmt;
        char *p;

        fmt = "<GnupgInfo>\n"
              " <engine>\n"
              "  <version>%s</version>\n"
              "  <path>%s</path>\n"
              " </engine>\n"
              "</GnupgInfo>\n";
        /*(yes, I know that we allocating 2 extra bytes)*/
        p = xtrymalloc ( strlen(fmt) + strlen(path)
                         + strlen (version) + 1);
        if (!p) {
            err = mk_error (Out_Of_Core);
            goto leave;
        }
        sprintf (p, fmt, version, path);
        engine_info = p;
        xfree (version);
    }
    else {
        err = mk_error (General_Error);
    }

 leave:
    if (err) {
        const char *fmt;
        const char *errstr = gpgme_strerror (err);
        char *p;

        fmt = "<GnupgInfo>\n"
            " <engine>\n"
            "  <error>%s</error>\n"                
            "  <path>%s</path>\n"
            " </engine>\n"
            "</GnupgInfo>\n";

        p = xtrymalloc ( strlen(fmt) + strlen(errstr) + strlen(path) + 1);
        if (p) { 
            sprintf (p, fmt, errstr, path);
            engine_info = p;
        }
        else {
            engine_info = "<GnupgInfo>\n"
                          "  <error>Out of core</error>\n"
                          "</GnupgInfo>\n";
        }
    }
    return engine_info;
}