/* Copyright (C) 1996 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Thorsten Kukuk <kukuk@vt.uni-paderborn.de>, 1996.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <nss.h>
#include <pwd.h>
#include <errno.h>
#include <ctype.h>
#include <netdb.h>
#include <string.h>
#include <libc-lock.h>
#include <rpcsvc/yp.h>
#include <rpcsvc/ypclnt.h>

#include "netgroup.h"

/* Structure for remembering -@netgroup and -user members ... */
#define BLACKLIST_INITIAL_SIZE 512
#define BLACKLIST_INCREMENT 256
struct blacklist_t
  {
    char *data;
    int current;
    int size;
  };

struct ent_t
  {
    bool_t netgroup;
    bool_t nis;
    bool_t first;
    char *oldkey;
    int oldkeylen;
    FILE *stream;
    struct blacklist_t blacklist;
    struct passwd pwd;
    struct __netgrent netgrdata;
  };
typedef struct ent_t ent_t;

static ent_t ext_ent = {0, 0, 0, NULL, 0, NULL, {NULL, 0, 0},
			{NULL, NULL, 0, 0, NULL, NULL, NULL}};

/* Protect global state against multiple changers.  */
__libc_lock_define_initialized (static, lock)

/* Prototypes for local functions.  */
static void blacklist_store_name (const char *, ent_t *);
static int in_blacklist (const char *, int, ent_t *);

static void
give_pwd_free (struct passwd *pwd)
{
  if (pwd->pw_name != NULL)
    free (pwd->pw_name);
  if (pwd->pw_passwd != NULL)
    free (pwd->pw_passwd);
  if (pwd->pw_gecos != NULL)
    free (pwd->pw_gecos);
  if (pwd->pw_dir != NULL)
    free (pwd->pw_dir);
  if (pwd->pw_shell != NULL)
    free (pwd->pw_shell);

  memset (pwd, '\0', sizeof (struct passwd));
}

static size_t
pwd_need_buflen (struct passwd *pwd)
{
  size_t len = 0;

  if (pwd->pw_passwd != NULL)
    len += strlen (pwd->pw_passwd) + 1;

  if (pwd->pw_gecos != NULL)
    len += strlen (pwd->pw_gecos) + 1;

  if (pwd->pw_dir != NULL)
    len += strlen (pwd->pw_dir) + 1;

  if (pwd->pw_shell != NULL)
    len += strlen (pwd->pw_shell) + 1;

  return len;
}

static void
copy_pwd_changes (struct passwd *dest, struct passwd *src,
		  char *buffer, size_t buflen)
{
  if (src->pw_passwd != NULL && strlen (src->pw_passwd))
    {
      if (buffer == NULL)
	dest->pw_passwd = strdup (src->pw_passwd);
      else if (dest->pw_passwd &&
	       strlen (dest->pw_passwd) >= strlen (src->pw_passwd))
	strcpy (dest->pw_passwd, src->pw_passwd);
      else
	{
	  dest->pw_passwd = buffer;
	  strcpy (dest->pw_passwd, src->pw_passwd);
	  buffer += strlen (dest->pw_passwd) + 1;
	  buflen = buflen - (strlen (dest->pw_passwd) + 1);
	}
    }

  if (src->pw_gecos != NULL && strlen (src->pw_gecos))
    {
      if (buffer == NULL)
	dest->pw_gecos = strdup (src->pw_gecos);
      else if (dest->pw_gecos &&
	       strlen (dest->pw_gecos) >= strlen (src->pw_gecos))
	strcpy (dest->pw_gecos, src->pw_gecos);
      else
	{
	  dest->pw_gecos = buffer;
	  strcpy (dest->pw_gecos, src->pw_gecos);
	  buffer += strlen (dest->pw_gecos) + 1;
	  buflen = buflen - (strlen (dest->pw_gecos) + 1);
	}
    }
  if (src->pw_dir != NULL && strlen (src->pw_dir))
    {
      if (buffer == NULL)
	dest->pw_dir = strdup (src->pw_dir);
      else if (dest->pw_dir &&
	       strlen (dest->pw_dir) >= strlen (src->pw_dir))
	strcpy (dest->pw_dir, src->pw_dir);
      else
	{
	  dest->pw_dir = buffer;
	  strcpy (dest->pw_dir, src->pw_dir);
	  buffer += strlen (dest->pw_dir) + 1;
	  buflen = buflen - (strlen (dest->pw_dir) + 1);
	}
    }

  if (src->pw_shell != NULL && strlen (src->pw_shell))
    {
      if (buffer == NULL)
	dest->pw_shell = strdup (src->pw_shell);
      else if (dest->pw_shell &&
	       strlen (dest->pw_shell) >= strlen (src->pw_shell))
	strcpy (dest->pw_shell, src->pw_shell);
      else
	{
	  dest->pw_shell = buffer;
	  strcpy (dest->pw_shell, src->pw_shell);
	  buffer += strlen (dest->pw_shell) + 1;
	  buflen = buflen - (strlen (dest->pw_shell) + 1);
	}
    }
}

static enum nss_status
internal_setpwent (ent_t *ent)
{
  enum nss_status status = NSS_STATUS_SUCCESS;

  ent->nis = ent->first = ent->netgroup = 0;

  /* If something was left over free it.  */
  if (ent->netgroup)
    __internal_endnetgrent (&ent->netgrdata);

  if (ent->oldkey != NULL)
    {
      free (ent->oldkey);
      ent->oldkey = NULL;
      ent->oldkeylen = 0;
    }

  ent->blacklist.current = 0;
  if (ent->blacklist.data != NULL)
    ent->blacklist.data[0] = '\0';

  if (ent->stream == NULL)
    {
      ent->stream = fopen ("/etc/passwd", "r");

      if (ent->stream == NULL)
	status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
    }
  else
    rewind (ent->stream);

  give_pwd_free (&ent->pwd);

  return status;
}


enum nss_status
_nss_compat_setpwent (void)
{
  enum nss_status result;

  __libc_lock_lock (lock);

  result = internal_setpwent (&ext_ent);

  __libc_lock_unlock (lock);

  return result;
}


static enum nss_status
internal_endpwent (ent_t *ent)
{
  if (ent->stream != NULL)
    {
      fclose (ent->stream);
      ent->stream = NULL;
    }

  ent->nis = ent->first = ent->netgroup = 0;

  if (ent->oldkey != NULL)
    {
      free (ent->oldkey);
      ent->oldkey = NULL;
      ent->oldkeylen = 0;
    }

  ent->blacklist.current = 0;
  if (ent->blacklist.data != NULL)
    ent->blacklist.data[0] = '\0';

  give_pwd_free (&ent->pwd);

  return NSS_STATUS_SUCCESS;
}

enum nss_status
_nss_compat_endpwent (void)
{
  enum nss_status result;

  __libc_lock_lock (lock);

  if (ext_ent.netgroup)
    __internal_endnetgrent (&ext_ent.netgrdata);

  result = internal_endpwent (&ext_ent);

  __libc_lock_unlock (lock);

  return result;
}

static enum nss_status
getpwent_next_netgr (struct passwd *result, ent_t *ent, char *group,
		     char *buffer, size_t buflen)
{
  char *ypdomain, *host, *user, *domain, *outval, *p, *p2;
  int status, outvallen;
  size_t p2len;

  if (yp_get_default_domain (&ypdomain) != YPERR_SUCCESS)
    {
      ent->netgroup = 0;
      ent->first = 0;
      give_pwd_free (&ent->pwd);
      return NSS_STATUS_UNAVAIL;
    }

  if (ent->first == TRUE)
    {
      bzero (&ent->netgrdata, sizeof (struct __netgrent));
      __internal_setnetgrent (group, &ent->netgrdata);
      ent->first = FALSE;
    }

  while (1)
    {
      status = __internal_getnetgrent (&host, &user, &domain, &ent->netgrdata,
				       buffer, buflen);
      if (status != 1)
	{
	  __internal_endnetgrent (&ent->netgrdata);
	  ent->netgroup = 0;
	  give_pwd_free (&ent->pwd);
	  return NSS_STATUS_RETURN;
	}

      if (user == NULL || user[0] == '-')
	continue;

      if (domain != NULL && strcmp (ypdomain, domain) != 0)
	continue;

      if (yp_match (ypdomain, "passwd.byname", user,
		    strlen (user), &outval, &outvallen)
	  != YPERR_SUCCESS)
	continue;

      p2len = pwd_need_buflen (&ent->pwd);
      if (p2len > buflen)
	{
	  __set_errno (ERANGE);
	  return NSS_STATUS_TRYAGAIN;
	}
      p2 = buffer + (buflen - p2len);
      buflen -= p2len;
      p = strncpy (buffer, outval, buflen);
      while (isspace (*p))
	p++;
      free (outval);
      if (_nss_files_parse_pwent (p, result, buffer, buflen))
	{
	  copy_pwd_changes (result, &ent->pwd, p2, p2len);
	  break;
	}
    }

  return NSS_STATUS_SUCCESS;
}

static enum nss_status
getpwent_next_nis (struct passwd *result, ent_t *ent, char *buffer,
		   size_t buflen)
{
  char *domain, *outkey, *outval, *p, *p2;
  int outkeylen, outvallen;
  size_t p2len;

  if (yp_get_default_domain (&domain) != YPERR_SUCCESS)
    {
      ent->nis = 0;
      give_pwd_free (&ent->pwd);
      return NSS_STATUS_UNAVAIL;
    }

  p2len = pwd_need_buflen (&ent->pwd);
  if (p2len > buflen)
    {
      __set_errno (ERANGE);
      return NSS_STATUS_TRYAGAIN;
    }
  p2 = buffer + (buflen - p2len);
  buflen -= p2len;
  do
    {
      if (ent->first)
	{
	  if (yp_first (domain, "passwd.byname", &outkey, &outkeylen,
			&outval, &outvallen) != YPERR_SUCCESS)
	    {
	      ent->nis = 0;
	      give_pwd_free (&ent->pwd);
	      return NSS_STATUS_UNAVAIL;
	    }

	  ent->oldkey = outkey;
	  ent->oldkeylen = outkeylen;
	  ent->first = FALSE;
	}
      else
	{
	  if (yp_next (domain, "passwd.byname", ent->oldkey, ent->oldkeylen,
		       &outkey, &outkeylen, &outval, &outvallen)
	      != YPERR_SUCCESS)
	    {
	      ent->nis = 0;
	      give_pwd_free (&ent->pwd);
	      return NSS_STATUS_NOTFOUND;
	    }

	  free (ent->oldkey);
	  ent->oldkey = outkey;
	  ent->oldkeylen = outkeylen;
	}

      /* Copy the found data to our buffer  */
      p = strncpy (buffer, outval, buflen);

      /* ...and free the data.  */
      free (outval);

      while (isspace (*p))
	++p;
    }
  while (!_nss_files_parse_pwent (p, result, buffer, buflen));

  copy_pwd_changes (result, &ent->pwd, p2, p2len);

  if (!in_blacklist (result->pw_name, strlen (result->pw_name), ent))
    return NSS_STATUS_SUCCESS;
  else
    return NSS_STATUS_NOTFOUND;
}


static enum nss_status
getpwent_next_file (struct passwd *result, ent_t *ent,
		    char *buffer, size_t buflen)
{
  while (1)
    {
      char *p, *p2;
      size_t p2len;

      do
	{
	  p = fgets (buffer, buflen, ent->stream);
	  if (p == NULL)
	    return NSS_STATUS_NOTFOUND;

	  /* Terminate the line for any case.  */
	  buffer[buflen - 1] = '\0';

	  /* Skip leading blanks.  */
	  while (isspace (*p))
	    ++p;
	}
      while (*p == '\0' || *p == '#' || /* Ignore empty and comment lines.  */
      /* Parse the line.  If it is invalid, loop to
         get the next line of the file to parse.  */
	     !_nss_files_parse_pwent (p, result, buffer, buflen));

      if (result->pw_name[0] != '+' && result->pw_name[0] != '-')
	/* This is a real entry.  */
	break;

      /* -@netgroup */
      if (result->pw_name[0] == '-' && result->pw_name[1] == '@'
	  && result->pw_name[2] != '\0')
	{
	  char *user, *host, *domain;

	  setnetgrent (&result->pw_name[2]);
	  while (getnetgrent (&host, &user, &domain))
	    {
	      if (user != NULL && user[0] != '-')
		blacklist_store_name (user, ent);
	    }
	  endnetgrent ();
	  continue;
	}

      /* +@netgroup */
      if (result->pw_name[0] == '+' && result->pw_name[1] == '@'
	  && result->pw_name[2] != '\0')
	{
	  int status;

	  ent->netgroup = TRUE;
	  ent->first = TRUE;
	  copy_pwd_changes (&ent->pwd, result, NULL, 0);

	  status = getpwent_next_netgr (result, ent, &result->pw_name[2],
					buffer, buflen);
	  if (status == NSS_STATUS_RETURN)
	    continue;
	  else
	    return status;
	}

      /* -user */
      if (result->pw_name[0] == '-' && result->pw_name[1] != '\0'
	  && result->pw_name[1] != '@')
	{
	  blacklist_store_name (&result->pw_name[1], ent);
	  continue;
	}

      /* +user */
      if (result->pw_name[0] == '+' && result->pw_name[1] != '\0'
	  && result->pw_name[1] != '@')
	{
	  char *domain;
	  char *outval;
	  int outvallen;
	  struct passwd pwd;

	  memset (&pwd, '\0', sizeof (struct passwd));

	  if (yp_get_default_domain (&domain) != YPERR_SUCCESS)
	    /* XXX Should we regard this as an fatal error?  I don't
	       think so.  Just continue working.  --drepper@gnu  */
	    continue;

	  if (yp_match (domain, "passwd.byname", &result->pw_name[1],
			strlen (result->pw_name) - 1, &outval, &outvallen)
	      != YPERR_SUCCESS)
	    continue;

	  copy_pwd_changes (&pwd, result, NULL, 0);

	  p2len = pwd_need_buflen (&pwd);
	  if (p2len > buflen)
	    {
	      __set_errno (ERANGE);
	      return NSS_STATUS_TRYAGAIN;
	    }
	  p2 = buffer + (buflen - p2len);
	  buflen -= p2len;
	  p = strncpy (buffer, outval, buflen);
	  while (isspace (*p))
	    p++;
	  free (outval);
	  if (_nss_files_parse_pwent (p, result, buffer, buflen))
	    {
	      copy_pwd_changes (result, &pwd, p2, p2len);
	      give_pwd_free (&pwd);
	      /* We found the entry.  */
	      break;
	    }
	  else
	    {
	      /* Give buffer the old len back */
	      buflen += p2len;
	      give_pwd_free (&pwd);
	    }
	}

      /* +:... */
      if (result->pw_name[0] == '+' && result->pw_name[1] == '\0')
	{
	  ent->nis = TRUE;
	  ent->first = TRUE;
	  copy_pwd_changes (&ent->pwd, result, NULL, 0);

	  return getpwent_next_nis (result, ent, buffer, buflen);
	}
    }

  return NSS_STATUS_SUCCESS;
}


static enum nss_status
internal_getpwent_r (struct passwd *pw, ent_t *ent, char *buffer,
		     size_t buflen)
{
  if (ent->netgroup)
    {
      int status;

      /* We are searching members in a netgroup */
      /* Since this is not the first call, we don't need the group name */
      status = getpwent_next_netgr (pw, ent, NULL, buffer, buflen);
      if (status == NSS_STATUS_RETURN)
	return getpwent_next_file (pw, ent, buffer, buflen);
      else
	return status;
    }
  else if (ent->nis)
    return getpwent_next_nis (pw, ent, buffer, buflen);
  else
    return getpwent_next_file (pw, ent, buffer, buflen);
}

enum nss_status
_nss_compat_getpwent_r (struct passwd *pwd, char *buffer,
			size_t buflen)
{
  enum nss_status status = NSS_STATUS_SUCCESS;

  __libc_lock_lock (lock);

  /* Be prepared that the setpwent function was not called before.  */
  if (ext_ent.stream == NULL)
    status = internal_setpwent (&ext_ent);

  if (status == NSS_STATUS_SUCCESS)
    status = internal_getpwent_r (pwd, &ext_ent, buffer, buflen);

  __libc_lock_unlock (lock);

  return status;
}


enum nss_status
_nss_compat_getpwnam_r (const char *name, struct passwd *pwd,
			char *buffer, size_t buflen)
{
  ent_t ent = {0, 0, 0, NULL, 0, NULL, {NULL, 0, 0},
	       {NULL, NULL, 0, 0, NULL, NULL, NULL}};
  enum nss_status status;

  if (name[0] == '-' || name[0] == '+')
    return NSS_STATUS_NOTFOUND;


  status = internal_setpwent (&ent);
  if (status != NSS_STATUS_SUCCESS)
    return status;

  while ((status = internal_getpwent_r (pwd, &ent, buffer, buflen))
	 == NSS_STATUS_SUCCESS)
    if (strcmp (pwd->pw_name, name) == 0)
      break;

  internal_endpwent (&ent);
  return status;
}


enum nss_status
_nss_compat_getpwuid_r (uid_t uid, struct passwd *pwd,
			char *buffer, size_t buflen)
{
  ent_t ent = {0, 0, 0, NULL, 0, NULL, {NULL, 0, 0},
	       {NULL, NULL, 0, 0, NULL, NULL, NULL}};
  enum nss_status status;

  status = internal_setpwent (&ent);
  if (status != NSS_STATUS_SUCCESS)
    return status;

  while ((status = internal_getpwent_r (pwd, &ent, buffer, buflen))
	 == NSS_STATUS_SUCCESS)
    if (pwd->pw_uid == uid && pwd->pw_name[0] != '+' && pwd->pw_name[0] != '-')
      break;

  internal_endpwent (&ent);
  return status;
}


/* Support routines for remembering -@netgroup and -user entries.
   The names are stored in a single string with `|' as separator. */
static void
blacklist_store_name (const char *name, ent_t *ent)
{
  int namelen = strlen (name);
  char *tmp;

  /* first call, setup cache */
  if (ent->blacklist.size == 0)
    {
      ent->blacklist.size = MAX (BLACKLIST_INITIAL_SIZE, 2 * namelen);
      ent->blacklist.data = malloc (ent->blacklist.size);
      if (ent->blacklist.data == NULL)
	return;
      ent->blacklist.data[0] = '|';
      ent->blacklist.data[1] = '\0';
      ent->blacklist.current = 1;
    }
  else
    {
      if (in_blacklist (name, namelen, ent))
	return;			/* no duplicates */

      if (ent->blacklist.current + namelen + 1 >= ent->blacklist.size)
	{
	  ent->blacklist.size += MAX (BLACKLIST_INCREMENT, 2 * namelen);
	  tmp = realloc (ent->blacklist.data, ent->blacklist.size);
	  if (tmp == NULL)
	    {
	      free (ent->blacklist.data);
	      ent->blacklist.size = 0;
	      return;
	    }
	  ent->blacklist.data = tmp;
	}
    }

  tmp = stpcpy (ent->blacklist.data + ent->blacklist.current, name);
  *tmp++ = '|';
  *tmp = '\0';
  ent->blacklist.current += namelen + 1;

  return;
}

/* returns TRUE if ent->blacklist contains name, else FALSE */
static bool_t
in_blacklist (const char *name, int namelen, ent_t *ent)
{
  char buf[namelen + 3];

  if (ent->blacklist.data == NULL)
    return FALSE;

  stpcpy (stpcpy (stpcpy (buf, "|"), name), "|");
  return strstr (ent->blacklist.data, buf) != NULL;
}