/* 
   Unix SMB/Netbios implementation.
   Version 1.9.
   Username handling
   Copyright (C) Andrew Tridgell 1992-1998
   
   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.
   
   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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/

#include "includes.h"
extern int DEBUGLEVEL;

/* internal functions */
static struct passwd *uname_string_combinations(char *s, struct passwd * (*fn) (const char *), int N);
static struct passwd *uname_string_combinations2(char *s, int offset, struct passwd * (*fn) (const char *), int N);

/****************************************************************************
get a users home directory.
****************************************************************************/
const char *get_home_dir(char *user)
{
  struct passwd *pass;

  pass = Get_Pwnam(user);

  if (!pass) return(NULL);
  return(pass->pw_dir);      
}


#if 0 /* Fix possible buffer overflow in sscanf(unixname,"%s",user) if uncomment */
/*******************************************************************
map a username from a dos name to a unix name by looking in the username
map. Note that this modifies the name in place.
This is the main function that should be called *once* on
any incoming or new username - in order to canonicalize the name.
This is being done to de-couple the case conversions from the user mapping
function. Previously, the map_username was being called
every time Get_Pwnam was called.
Returns True if username was changed, false otherwise.
********************************************************************/
BOOL map_username(const char *user)
{
  static BOOL initialised=False;
  static fstring last_from,last_to;
  FILE *f;
  char *mapfile = lp_username_map();
  char *s;
  pstring buf;
  BOOL mapped_user = False;

  if (!*user)
    return False;

  if (!*mapfile)
    return False;

  if (!initialised) {
    *last_from = *last_to = 0;
    initialised = True;
  }

  if (strequal(user,last_to))
    return False;

  if (strequal(user,last_from)) {
    DEBUG(3,("Mapped user %s to %s\n",user,last_to));
    fstrcpy(user,last_to);
    return True;
  }
  
  f = sys_fopen(mapfile,"r");
  if (!f) {
    DEBUG(0,("can't open username map %s\n",mapfile));
    return False;
  }

  DEBUG(4,("Scanning username map %s\n",mapfile));

  while((s=fgets_slash(buf,sizeof(buf),f))!=NULL) {
    char *unixname = s;
    char *dosname = strchr(unixname,'=');
    BOOL return_if_mapped = False;

    if (!dosname)
      continue;

    *dosname++ = 0;

    while (isspace(*unixname))
      unixname++;
    if ('!' == *unixname) {
      return_if_mapped = True;
      unixname++;
      while (*unixname && isspace(*unixname))
        unixname++;
    }
    
    if (!*unixname || strchr("#;",*unixname))
      continue;

    {
      int l = strlen(unixname);
      while (l && isspace(unixname[l-1])) {
        unixname[l-1] = 0;
        l--;
      }
    }

    if (strchr(dosname,'*') || user_in_list(user,dosname)) {
      DEBUG(3,("Mapped user %s to %s\n",user,unixname));
      mapped_user = True;
      fstrcpy(last_from,user);
      sscanf(unixname,"%s",user);
      fstrcpy(last_to,user);
      if(return_if_mapped) { 
        fclose(f);
        return True;
      }
    }
  }

  fclose(f);

  /*
   * Setup the last_from and last_to as an optimization so 
   * that we don't scan the file again for the same user.
   */
  fstrcpy(last_from,user);
  fstrcpy(last_to,user);

  return mapped_user;
}
#endif /* 0 */

/****************************************************************************
Get_Pwnam wrapper
****************************************************************************/
static struct passwd *_Get_Pwnam(const char *s)
{
  struct passwd *ret;

  ret = getpwnam(s);
  if (ret)
    {
#ifdef HAVE_GETPWANAM
      struct passwd_adjunct *pwret;
      pwret = getpwanam(s);
      if (pwret)
	{
	  free(ret->pw_passwd);
	  ret->pw_passwd = pwret->pwa_passwd;
	}
#endif

    }

  return(ret);
}


/****************************************************************************
a wrapper for getpwnam() that tries with all lower and all upper case 
if the initial name fails. Also tried with first letter capitalised
****************************************************************************/
struct passwd *Get_Pwnam(const char *a_user)
{
  fstring user;
  int last_char;
  int usernamelevel = lp_usernamelevel();

  struct passwd *ret;  

  if (!a_user || !(*a_user))
    return(NULL);

  StrnCpy(user,a_user,sizeof(user)-1);

  ret = _Get_Pwnam(user);
  if (ret) return(ret);

  strlower(user);
  ret = _Get_Pwnam(user);
  if (ret)  return(ret);

  strupper(user);
  ret = _Get_Pwnam(user);
  if (ret) return(ret);

  /* try with first letter capitalised */
  if (strlen(user) > 1)
    strlower(user+1);  
  ret = _Get_Pwnam(user);
  if (ret) return(ret);

  /* try with last letter capitalised */
  strlower(user);
  last_char = strlen(user)-1;
  user[last_char] = toupper(user[last_char]);
  ret = _Get_Pwnam(user);
  if (ret) return(ret);

  /* try all combinations up to usernamelevel */
  strlower(user);
  ret = uname_string_combinations(user, _Get_Pwnam, usernamelevel);
  if (ret) return(ret);

  return(NULL);
}

#if 0
/****************************************************************************
check if a user is in a netgroup user list
****************************************************************************/
static BOOL user_in_netgroup_list(char *user,char *ngname)
{
#ifdef HAVE_NETGROUP
  static char *mydomain = NULL;
  if (mydomain == NULL)
    yp_get_default_domain(&mydomain);

  if(mydomain == NULL)
  {
    DEBUG(5,("Unable to get default yp domain\n"));
  }
  else
  {
    DEBUG(5,("looking for user %s of domain %s in netgroup %s\n",
          user, mydomain, ngname));
    DEBUG(5,("innetgr is %s\n",
          innetgr(ngname, NULL, user, mydomain)
          ? "TRUE" : "FALSE"));

    if (innetgr(ngname, NULL, user, mydomain))
      return (True);
  }
#endif /* HAVE_NETGROUP */
  return False;
}

/****************************************************************************
check if a user is in a UNIX user list
****************************************************************************/
static BOOL user_in_group_list(char *user,char *gname)
{
#ifdef HAVE_GETGRNAM 
  struct group *gptr;
  char **member;  
  struct passwd *pass = Get_Pwnam(user,False);

  if (pass)
  { 
    gptr = getgrgid(pass->pw_gid);
    if (gptr && strequal(gptr->gr_name,gname))
      return(True); 
  } 

  gptr = (struct group *)getgrnam(gname);

  if (gptr)
  {
    member = gptr->gr_mem;
    while (member && *member)
    {
      if (strequal(*member,user))
        return(True);
      member++;
    }
  }
#endif /* HAVE_GETGRNAM */
  return False;
}	      

/****************************************************************************
check if a user is in a user list - can check combinations of UNIX
and netgroup lists.
****************************************************************************/
BOOL user_in_list(char *user,char *list)
{
  pstring tok;
  char *p=list;

  while (next_token(&p,tok,LIST_SEP, sizeof(tok)))
  {
    /*
     * Check raw username.
     */
    if (strequal(user,tok))
      return(True);

    /*
     * Now check to see if any combination
     * of UNIX and netgroups has been specified.
     */

    if(*tok == '@')
    {
      /*
       * Old behaviour. Check netgroup list
       * followed by UNIX list.
       */
      if(user_in_netgroup_list(user,&tok[1]))
        return True;
      if(user_in_group_list(user,&tok[1]))
        return True;
    }
    else if (*tok == '+')
    {
      if(tok[1] == '&')
      {
        /*
         * Search UNIX list followed by netgroup.
         */
        if(user_in_group_list(user,&tok[2]))
          return True;
        if(user_in_netgroup_list(user,&tok[2]))
          return True;
      }
      else
      {
        /*
         * Just search UNIX list.
         */
        if(user_in_group_list(user,&tok[1]))
          return True;
      }
    }
    else if (*tok == '&')
    {
      if(tok[1] == '&')
      {
        /*
         * Search netgroup list followed by UNIX list.
         */
        if(user_in_netgroup_list(user,&tok[2]))
          return True;
        if(user_in_group_list(user,&tok[2]))
          return True;
      }
      else
      {
        /*
         * Just search netgroup list.
         */
        if(user_in_netgroup_list(user,&tok[1]))
          return True;
      }
    }
  }
  return(False);
}
#endif /* 0 */

/* The functions below have been taken from password.c and slightly modified */
/****************************************************************************
apply a function to upper/lower case combinations
of a string and return true if one of them returns true.
try all combinations with N uppercase letters.
offset is the first char to try and change (start with 0)
it assumes the string starts lowercased
****************************************************************************/
static struct passwd *uname_string_combinations2(char *s,int offset,struct passwd *(*fn)(const char *),int N)
{
  int len = strlen(s);
  int i;
  struct passwd *ret;

#ifdef PASSWORD_LENGTH
  len = MIN(len,PASSWORD_LENGTH);
#endif

  if (N <= 0 || offset >= len)
    return(fn(s));


  for (i=offset;i<(len-(N-1));i++)

    {
      char c = s[i];
      if (!islower(c)) continue;
      s[i] = toupper(c);
      ret = uname_string_combinations2(s,i+1,fn,N-1);
      if(ret) return(ret);
      s[i] = c;
    }
  return(NULL);
}

/****************************************************************************
apply a function to upper/lower case combinations
of a string and return true if one of them returns true.
try all combinations with up to N uppercase letters.
offset is the first char to try and change (start with 0)
it assumes the string starts lowercased
****************************************************************************/
static struct passwd * uname_string_combinations(char *s,struct passwd * (*fn)(const char *),int N)
{
  int n;
  struct passwd *ret;

  for (n=1;n<=N;n++)
  {
    ret = uname_string_combinations2(s,0,fn,n);
    if(ret) return(ret);
  }
  return(NULL);
}
