/* 
   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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "includes.h"
extern int DEBUGLEVEL;

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

/****************************************************************************
  Since getpwnam() makes samba really slow with the NT-domain code
  (reading /etc/passwd again and again and again), here is an implementation
  of very simple passwd cache
****************************************************************************/
#define PASSWD_HASH_SIZE 1009
/* The hashtable is rebuild every 15 seconds */
#define PASSWD_HASH_AGE 15
struct passwd_hash_entry {
  int entry;
  int next;
};

struct passwd_hash_table_s {
  struct passwd *passwds;
  int passwds_size;  
  int *names;
  int *uids;
  struct passwd_hash_entry *entries;
  int entries_size;
  struct timeval build_time;
} passwd_hash_table = {
  NULL,0,NULL,NULL,NULL,0,{0,0}
};

static int name_hash_function(const char *name) 
{
  /* I guess that there must be better hash functions. This one was the
   * first to come into mind :) */
  unsigned int value=0;
  while (*name) {
    value=(value<<8)|(unsigned char)(*name);
    if (value>1048576) value=value%PASSWD_HASH_SIZE;
    name++;
  }
  value=value%PASSWD_HASH_SIZE;
  return value;
}
    
static int uid_hash_function(uid_t uid) 
{
  return uid%PASSWD_HASH_SIZE;
}


static BOOL build_passwd_hash_table(void) 
{
  struct passwd_hash_table_s *pht=&passwd_hash_table; /* Convenience */
  int num_passwds=0;
  int num_entries=0;
  struct passwd *pass;
  int i;
  int name_i,uid_i;

  DEBUG(3,("Building passwd hash table\n"));
  /* Free the allocated strings in old hash table */
  for (i=0;i<pht->passwds_size;i++) {
    free(pht->passwds[i].pw_name);
    free(pht->passwds[i].pw_passwd);
    free(pht->passwds[i].pw_gecos);
    free(pht->passwds[i].pw_dir);
    free(pht->passwds[i].pw_shell);    
  }

  /* Initialize hash table if first table build */
  if (pht->passwds_size==0) {
    DEBUG(3,("Building passwd hash table for the first time\n"));
    pht->passwds=malloc(sizeof(struct passwd)*64); /* A reasonable default */
    pht->passwds_size=64;
  }
  if (pht->names==NULL) {
    pht->names=malloc(sizeof(struct passwd_hash_entry *)*PASSWD_HASH_SIZE);
  }
  if (pht->uids==NULL) {
    pht->uids=malloc(sizeof(struct passwd_hash_entry *)*PASSWD_HASH_SIZE);
  }
  if (pht->entries==NULL) {
    pht->entries=malloc(sizeof(struct passwd_hash_entry)*128);
    pht->entries_size=128;
  }
  if (pht->passwds==NULL || pht->names==NULL || 
      pht->uids==NULL || pht->entries==NULL) {
    goto fail;
  }
  
  /* Clear out the hash table */
  for(i=0;i<PASSWD_HASH_SIZE;i++) pht->uids[i]=-1;
  for(i=0;i<PASSWD_HASH_SIZE;i++) pht->names[i]=-1;

  /* Now do the build */
  setpwent();

  while((pass=getpwent())) {

    /* Check that we have enough space */
    if (num_passwds==pht->passwds_size) {
      struct passwd *new_passwds=NULL;
      pht->passwds_size+=pht->passwds_size/2;
      new_passwds=realloc(pht->passwds,
			   sizeof(struct passwd)*pht->passwds_size);
      if (new_passwds==NULL) goto fail;
      pht->passwds=new_passwds;
    }
    if (num_entries+1>=pht->entries_size) {
      pht->entries_size+=pht->entries_size/2;
      pht->entries=realloc(pht->entries,
			   sizeof(struct passwd_hash_entry)*pht->entries_size);
      if (pht->entries==NULL) goto fail;
    }

    /* Copy the passwd struct */
    memset(&pht->passwds[num_passwds],0,sizeof(struct passwd));
    pht->passwds[num_passwds].pw_uid=pass->pw_uid;
    pht->passwds[num_passwds].pw_gid=pass->pw_gid;  
    if (
	(pht->passwds[num_passwds].pw_name=strdup(pass->pw_name))==NULL ||
	(pht->passwds[num_passwds].pw_passwd=strdup(pass->pw_passwd))==NULL ||
	(pht->passwds[num_passwds].pw_gecos=strdup(pass->pw_gecos))==NULL ||
	(pht->passwds[num_passwds].pw_dir=strdup(pass->pw_dir))==NULL ||
	(pht->passwds[num_passwds].pw_shell=strdup(pass->pw_shell))==NULL ) {
      num_passwds++;
      goto fail;
    }
    
    /* Add to the hash table */
    /* Add the name */
    pht->entries[num_entries].entry=num_passwds;
    name_i=name_hash_function(pass->pw_name);
    pht->entries[num_entries].next=pht->names[name_i];
    pht->names[name_i]=num_entries;
    num_entries++;
    /* Add the uid */
    pht->entries[num_entries].entry=num_passwds;
    uid_i=uid_hash_function(pass->pw_uid);
    pht->entries[num_entries].next=pht->uids[uid_i];
    pht->uids[uid_i]=num_entries;
    num_entries++;

    /* This entry has been done */
    num_passwds++;
  }    
  endpwent();
  
  if (pht->passwds_size>num_passwds) {
    struct passwd *passwds;
    passwds=realloc(pht->passwds,sizeof(pht->passwds[0])*num_passwds);
    if (passwds==NULL) goto fail;
    pht->passwds=passwds;
    pht->passwds_size=num_passwds;
  }
  if (pht->entries_size>num_entries) {
    struct passwd_hash_entry *entries;
    entries=realloc(pht->entries,sizeof(pht->entries[0])*num_entries);
    if (entries==NULL) goto fail;
    pht->entries=entries;
    pht->entries_size=num_entries;
  }

  /* Mark the creation time */
  GetTimeOfDay(&pht->build_time);
  /* Everything went smoothly. */
  return True;

 fail:
  DEBUG(0,("Failed to create passwd hash table: %s",strerror(errno)));
  /* OK: now the untested part. Normally this should never happen:
   * Only running out of memory could cause this and even then
   * we have enough trouble already. */
  while (num_passwds>0) {
    num_passwds--;
    free(pht->passwds[num_passwds].pw_name);
    free(pht->passwds[num_passwds].pw_passwd);
    free(pht->passwds[num_passwds].pw_gecos);
    free(pht->passwds[num_passwds].pw_dir);
    free(pht->passwds[num_passwds].pw_shell);    
  }
  free(pht->entries);
  free(pht->uids);
  free(pht->names);
  free(pht->passwds);
  pht->passwds_size=0;
  pht->entries_size=0;    
  /* Also mark fail time, so that retry will happen after PASSWD_HASH_AGE */
  GetTimeOfDay(&pht->build_time);
  return False;
}

static BOOL have_passwd_hash(void)
{
  struct passwd_hash_table_s *pht=&passwd_hash_table;
  struct timeval tv;
  GetTimeOfDay(&tv);
  /* I'm ignoring microseconds. If you think they matter, go ahead
   * and implement them */
  if (tv.tv_sec - pht->build_time.tv_sec > PASSWD_HASH_AGE) {
    return build_passwd_hash_table();
  }
  return pht->passwds_size>0;
}

struct passwd *hashed_getpwnam(const char *name)
{
  struct passwd_hash_table_s *pht=&passwd_hash_table;

  DEBUG(5,("getpwnam(%s)\n", name));

  if (have_passwd_hash()) {
    int name_i=name_hash_function(name);
    int hash_index=pht->names[name_i];
    while(hash_index!=-1) {
      struct passwd *pass=&pht->passwds[pht->entries[hash_index].entry];
      if (strcmp(name,pass->pw_name)==0) {
	DEBUG(5,("Found: %s:%s:%d:%d:%s:%s:%s\n",
		 pass->pw_name,
		 pass->pw_passwd,
		 pass->pw_uid,
		 pass->pw_gid,
		 pass->pw_gecos,
		 pass->pw_dir,
		 pass->pw_shell));
	return pass;      
      }
      hash_index=pht->entries[hash_index].next;
    }

    /* Not found */
    DEBUG(5,("%s not found\n",name));
    return NULL;
  } 
  /* Fall back to real getpwnam() */
  return getpwnam(name);
}

/*******************************************************************
turn a uid into a user name
********************************************************************/
char *uidtoname(uid_t uid)
{
  static char name[40];
  struct passwd_hash_table_s *pht=&passwd_hash_table;
  struct passwd *pass=NULL;

  DEBUG(5,("uidtoname(%d)\n",uid));
  if (have_passwd_hash()) {
    int hash_index=pht->uids[uid_hash_function(uid)];
    while(hash_index!=-1) {
      pass=&pht->passwds[pht->entries[hash_index].entry];
      if (pass->pw_uid==uid) {
	DEBUG(5,("Found: %s:%s:%d:%d:%s:%s:%s\n",
		 pass->pw_name,
		 pass->pw_passwd,
		 pass->pw_uid,
		 pass->pw_gid,
		 pass->pw_gecos,
		 pass->pw_dir,
		 pass->pw_shell));
	return pass->pw_name;      
      }
      hash_index=pht->entries[hash_index].next;
    }
    DEBUG(5,("Hash miss"));
    pass=NULL;
  } else {
    /* No hash table, fall back to getpwuid */
    pass = getpwuid(uid);
  }
  if (pass) return(pass->pw_name);
  slprintf(name, sizeof(name) - 1, "%d",(int)uid);
  return(name);
}

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

	pass = Get_Pwnam(user, False);

	if (pass == NULL || pass->pw_dir == NULL) return(NULL);

	pstrcpy(home_dir, pass->pw_dir);
	DEBUG(10,("get_home_dir: returning %s for user %s\n", home_dir, user));
	return home_dir;
}


/*******************************************************************
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(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;
}

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

  ret = hashed_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
Note that this can change user!
****************************************************************************/
struct passwd *Get_Pwnam(char *user,BOOL allow_change)
{
  fstring user2;
  int last_char;
  int usernamelevel = lp_usernamelevel();

  struct passwd *ret;  

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

  StrnCpy(user2,user,sizeof(user2)-1);

  if (!allow_change) {
    user = &user2[0];
  }

  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);

  if (allow_change)
    fstrcpy(user,user2);

  return(NULL);
}

/****************************************************************************
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);
}

/* 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)(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)(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);
}