/*

  silcunixutil.c

  Author: Pekka Riikonen <priikone@poseidon.pspt.fi>

  Copyright (C) 1997 - 2000 Pekka Riikonen

  This program 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.
  
  This program 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.

*/
/*
 * These are general utility functions that doesn't belong to any specific
 * group of routines.
 */
/* $Id$ */

#include "silcincludes.h"

/* XXX lib/contrib/regex.c might cmopile on WIN32 as well */

/* Inspects the `string' for wildcards and returns regex string that can
   be used by the GNU regex library. A comma (`,') in the `string' means
   that the string is list. */

char *silc_string_regexify(const char *string)
{
  int i, len, count;
  char *regex;

  len = strlen(string);
  count = 4;
  for (i = 0; i < len; i++)
    if (string[i] == '*' || string[i] == '?')
      count++;

  regex = silc_calloc(len + count, sizeof(*regex));

  count = 0;
  regex[count] = '(';
  count++;

  for (i = 0; i < len; i++) {
    if (string[i] == '*' || string[i] == '?') {
      regex[count] = '.';
      count++;
    } else if (string[i] == ',') {
      regex[count] = '|';
      count++;
      continue;
    }

    regex[count] = string[i];
    count++;
  }

  regex[count - 1] = ')';
  regex[count] = '$';

  return regex;
}

/* Combines two regex strings into one regex string so that they can be
   used as one by the GNU regex library. The `string2' is combine into
   the `string1'. */

char *silc_string_regex_combine(const char *string1, const char *string2)
{
  char *tmp;
  int len1, len2;

  len1 = strlen(string1);
  len2 = strlen(string2);

  tmp = silc_calloc(2 + len1 + len2, sizeof(*tmp));
  strncat(tmp, string1, len1 - 2);
  strncat(tmp, "|", 1);
  strncat(tmp, string2 + 1, len2 - 1);

  return tmp;
}

/* Matches the two strings and returns TRUE if the strings match. */

int silc_string_regex_match(const char *regex, const char *string)
{
  regex_t preg;
  int ret = FALSE;
  
  if (regcomp(&preg, regex, REG_NOSUB | REG_EXTENDED) < 0)
    return FALSE;

  if (regexec(&preg, string, 0, NULL, 0) == 0)
    ret = TRUE;

  regfree(&preg);

  return ret;
}

/* Do regex match to the two strings `string1' and `string2'. If the
   `string2' matches the `string1' this returns TRUE. */

int silc_string_match(const char *string1, const char *string2)
{
  char *s1;
  int ret = FALSE;

  s1 = silc_string_regexify(string1);
  ret = silc_string_regex_match(s1, string2);
  silc_free(s1);

  return ret;
}

/* Returns the username of the user. If the global variable LOGNAME
   does not exists we will get the name from the password file. */

char *silc_get_username()
{
  char *logname = NULL;
  
  logname = getenv("LOGNAME");
  if (!logname) {
    logname = getlogin();
    if (!logname) {
      struct passwd *pw;

      pw = getpwuid(getuid());
      if (!pw) {
	fprintf(stderr, "silc_get_username: %s\n", strerror(errno));
	return NULL;
      }
      
      logname = pw->pw_name;
    }
  }
  
  return strdup(logname);
}                          

/* Returns the real name of ther user. */

char *silc_get_real_name()
{
  char *realname = NULL;
  struct passwd *pw;
    
  pw = getpwuid(getuid());
  if (!pw) {
    fprintf(stderr, "silc_get_username: %s\n", strerror(errno));
    return NULL;
  }

  if (strchr(pw->pw_gecos, ','))
    *strchr(pw->pw_gecos, ',') = 0;

  realname = strdup(pw->pw_gecos);

  return realname;
}