/*-
 * Copyright (c) 1992 Keith Muller.
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Keith Muller of the University of California, San Diego.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*-
 * Copyright (c) 2002 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#include <sys/types.h>
#include <sys/param.h>

#include <assert.h>
#include <grp.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "pwcache.h"

/*
 * routines that control user, group, uid and gid caches (for the archive
 * member print routine).
 * IMPORTANT:
 * these routines cache BOTH hits and misses, a major performance improvement
 */

/*
 * function pointers to various name lookup routines.
 * these may be changed as necessary.
 */
static int (*_pwcache_setgroupent)(int) = setgroupent;
static void (*_pwcache_endgrent)(void) = endgrent;
static struct group *(*_pwcache_getgrnam)(const char *) = getgrnam;
static struct group *(*_pwcache_getgrgid)(gid_t) = getgrgid;
static int (*_pwcache_setpassent)(int) = setpassent;
static void (*_pwcache_endpwent)(void) = endpwent;
static struct passwd *(*_pwcache_getpwnam)(const char *) = getpwnam;
static struct passwd *(*_pwcache_getpwuid)(uid_t) = getpwuid;

/*
 * internal state
 */
static int pwopn;    /* is password file open */
static int gropn;    /* is group file open */
static UIDC **uidtb; /* uid to name cache */
static GIDC **gidtb; /* gid to name cache */
static UIDC **usrtb; /* user name to uid cache */
static GIDC **grptb; /* group name to gid cache */

static int uidtb_fail; /* uidtb_start() failed ? */
static int gidtb_fail; /* gidtb_start() failed ? */
static int usrtb_fail; /* usrtb_start() failed ? */
static int grptb_fail; /* grptb_start() failed ? */

static u_int st_hash(const char *, size_t, int);
static int uidtb_start(void);
static int gidtb_start(void);
static int usrtb_start(void);
static int grptb_start(void);

static u_int st_hash(const char *name, size_t len, int tabsz) {
  u_int key = 0;

  _DIAGASSERT(name != NULL);

  while (len--) {
    key += *name++;
    key = (key << 8) | (key >> 24);
  }

  return (key % tabsz);
}

/*
 * uidtb_start
 *	creates an empty uidtb
 * Return:
 *	0 if ok, -1 otherwise
 */
static int uidtb_start(void) {

  if (uidtb != NULL)
    return (0);
  if (uidtb_fail)
    return (-1);
  if ((uidtb = (UIDC **)calloc(UID_SZ, sizeof(UIDC *))) == NULL) {
    ++uidtb_fail;
    return (-1);
  }
  return (0);
}

/*
 * gidtb_start
 *	creates an empty gidtb
 * Return:
 *	0 if ok, -1 otherwise
 */
static int gidtb_start(void) {

  if (gidtb != NULL)
    return (0);
  if (gidtb_fail)
    return (-1);
  if ((gidtb = (GIDC **)calloc(GID_SZ, sizeof(GIDC *))) == NULL) {
    ++gidtb_fail;
    return (-1);
  }
  return (0);
}

/*
 * usrtb_start
 *	creates an empty usrtb
 * Return:
 *	0 if ok, -1 otherwise
 */
static int usrtb_start(void) {

  if (usrtb != NULL)
    return (0);
  if (usrtb_fail)
    return (-1);
  if ((usrtb = (UIDC **)calloc(UNM_SZ, sizeof(UIDC *))) == NULL) {
    ++usrtb_fail;
    return (-1);
  }
  return (0);
}

/*
 * grptb_start
 *	creates an empty grptb
 * Return:
 *	0 if ok, -1 otherwise
 */
static int grptb_start(void) {

  if (grptb != NULL)
    return (0);
  if (grptb_fail)
    return (-1);
  if ((grptb = (GIDC **)calloc(GNM_SZ, sizeof(GIDC *))) == NULL) {
    ++grptb_fail;
    return (-1);
  }
  return (0);
}

/*
 * user_from_uid()
 *	caches the name (if any) for the uid. If noname clear, we always
 *	return the stored name (if valid or invalid match).
 *	We use a simple hash table.
 * Return
 *	Pointer to stored name (or a empty string)
 */
const char *user_from_uid(uid_t uid, int noname) {
  struct passwd *pw;
  UIDC *ptr, **pptr;

  if ((uidtb == NULL) && (uidtb_start() < 0))
    return (NULL);

  /*
   * see if we have this uid cached
   */
  pptr = uidtb + (uid % UID_SZ);
  ptr = *pptr;

  if ((ptr != NULL) && (ptr->valid > 0) && (ptr->uid == uid)) {
    /*
     * have an entry for this uid
     */
    if (!noname || (ptr->valid == VALID))
      return (ptr->name);
    return (NULL);
  }

  /*
   * No entry for this uid, we will add it
   */
  if (!pwopn) {
    if (_pwcache_setpassent != NULL)
      (*_pwcache_setpassent)(1);
    ++pwopn;
  }

  if (ptr == NULL)
    *pptr = ptr = (UIDC *)malloc(sizeof(UIDC));

  if ((pw = (*_pwcache_getpwuid)(uid)) == NULL) {
    /*
     * no match for this uid in the local password file
     * a string that is the uid in numeric format
     */
    if (ptr == NULL)
      return (NULL);
    ptr->uid = uid;
    (void)snprintf(ptr->name, UNMLEN, "%lu", (long)uid);
    ptr->valid = INVALID;
    if (noname)
      return (NULL);
  } else {
    /*
     * there is an entry for this uid in the password file
     */
    if (ptr == NULL)
      return (pw->pw_name);
    ptr->uid = uid;
    (void)strlcpy(ptr->name, pw->pw_name, UNMLEN);
    ptr->valid = VALID;
  }
  return (ptr->name);
}

/*
 * group_from_gid()
 *	caches the name (if any) for the gid. If noname clear, we always
 *	return the stored name (if valid or invalid match).
 *	We use a simple hash table.
 * Return
 *	Pointer to stored name (or a empty string)
 */
const char *group_from_gid(gid_t gid, int noname) {
  struct group *gr;
  GIDC *ptr, **pptr;

  if ((gidtb == NULL) && (gidtb_start() < 0))
    return (NULL);

  /*
   * see if we have this gid cached
   */
  pptr = gidtb + (gid % GID_SZ);
  ptr = *pptr;

  if ((ptr != NULL) && (ptr->valid > 0) && (ptr->gid == gid)) {
    /*
     * have an entry for this gid
     */
    if (!noname || (ptr->valid == VALID))
      return (ptr->name);
    return (NULL);
  }

  /*
   * No entry for this gid, we will add it
   */
  if (!gropn) {
    if (_pwcache_setgroupent != NULL)
      (*_pwcache_setgroupent)(1);
    ++gropn;
  }

  if (ptr == NULL)
    *pptr = ptr = (GIDC *)malloc(sizeof(GIDC));

  if ((gr = (*_pwcache_getgrgid)(gid)) == NULL) {
    /*
     * no match for this gid in the local group file, put in
     * a string that is the gid in numberic format
     */
    if (ptr == NULL)
      return (NULL);
    ptr->gid = gid;
    (void)snprintf(ptr->name, GNMLEN, "%lu", (long)gid);
    ptr->valid = INVALID;
    if (noname)
      return (NULL);
  } else {
    /*
     * there is an entry for this group in the group file
     */
    if (ptr == NULL)
      return (gr->gr_name);
    ptr->gid = gid;
    (void)strlcpy(ptr->name, gr->gr_name, GNMLEN);
    ptr->valid = VALID;
  }
  return (ptr->name);
}

/*
 * uid_from_user()
 *	caches the uid for a given user name. We use a simple hash table.
 * Return
 *	the uid (if any) for a user name, or a -1 if no match can be found
 */
int uid_from_user(const char *name, uid_t *uid) {
  struct passwd *pw;
  UIDC *ptr, **pptr;
  size_t namelen;

  /*
   * return -1 for mangled names
   */
  if (name == NULL || ((namelen = strlen(name)) == 0))
    return (-1);
  if ((usrtb == NULL) && (usrtb_start() < 0))
    return (-1);

  /*
   * look up in hash table, if found and valid return the uid,
   * if found and invalid, return a -1
   */
  pptr = usrtb + st_hash(name, namelen, UNM_SZ);
  ptr = *pptr;

  if ((ptr != NULL) && (ptr->valid > 0) && !strcmp(name, ptr->name)) {
    if (ptr->valid == INVALID)
      return (-1);
    *uid = ptr->uid;
    return (0);
  }

  if (!pwopn) {
    if (_pwcache_setpassent != NULL)
      (*_pwcache_setpassent)(1);
    ++pwopn;
  }

  if (ptr == NULL)
    *pptr = ptr = (UIDC *)malloc(sizeof(UIDC));

  /*
   * no match, look it up, if no match store it as an invalid entry,
   * or store the matching uid
   */
  if (ptr == NULL) {
    if ((pw = (*_pwcache_getpwnam)(name)) == NULL)
      return (-1);
    *uid = pw->pw_uid;
    return (0);
  }
  (void)strlcpy(ptr->name, name, UNMLEN);
  if ((pw = (*_pwcache_getpwnam)(name)) == NULL) {
    ptr->valid = INVALID;
    return (-1);
  }
  ptr->valid = VALID;
  *uid = ptr->uid = pw->pw_uid;
  return (0);
}

/*
 * gid_from_group()
 *	caches the gid for a given group name. We use a simple hash table.
 * Return
 *	the gid (if any) for a group name, or a -1 if no match can be found
 */
int gid_from_group(const char *name, gid_t *gid) {
  struct group *gr;
  GIDC *ptr, **pptr;
  size_t namelen;

  /*
   * return -1 for mangled names
   */
  if (name == NULL || ((namelen = strlen(name)) == 0))
    return (-1);
  if ((grptb == NULL) && (grptb_start() < 0))
    return (-1);

  /*
   * look up in hash table, if found and valid return the uid,
   * if found and invalid, return a -1
   */
  pptr = grptb + st_hash(name, namelen, GID_SZ);
  ptr = *pptr;

  if ((ptr != NULL) && (ptr->valid > 0) && !strcmp(name, ptr->name)) {
    if (ptr->valid == INVALID)
      return (-1);
    *gid = ptr->gid;
    return (0);
  }

  if (!gropn) {
    if (_pwcache_setgroupent != NULL)
      (*_pwcache_setgroupent)(1);
    ++gropn;
  }

  if (ptr == NULL)
    *pptr = ptr = (GIDC *)malloc(sizeof(GIDC));

  /*
   * no match, look it up, if no match store it as an invalid entry,
   * or store the matching gid
   */
  if (ptr == NULL) {
    if ((gr = (*_pwcache_getgrnam)(name)) == NULL)
      return (-1);
    *gid = gr->gr_gid;
    return (0);
  }

  (void)strlcpy(ptr->name, name, GNMLEN);
  if ((gr = (*_pwcache_getgrnam)(name)) == NULL) {
    ptr->valid = INVALID;
    return (-1);
  }
  ptr->valid = VALID;
  *gid = ptr->gid = gr->gr_gid;
  return (0);
}

#define FLUSHTB(arr, len, fail)                                                \
  do {                                                                         \
    if (arr != NULL) {                                                         \
      for (i = 0; i < len; i++)                                                \
        if (arr[i] != NULL)                                                    \
          free(arr[i]);                                                        \
      arr = NULL;                                                              \
    }                                                                          \
    fail = 0;                                                                  \
  } while (/* CONSTCOND */ 0);

int pwcache_userdb(int (*a_setpassent)(int), void (*a_endpwent)(void),
                   struct passwd *(*a_getpwnam)(const char *),
                   struct passwd *(*a_getpwuid)(uid_t)) {
  int i;

  /* a_setpassent and a_endpwent may be NULL */
  if (a_getpwnam == NULL || a_getpwuid == NULL)
    return (-1);

  if (_pwcache_endpwent != NULL)
    (*_pwcache_endpwent)();
  FLUSHTB(uidtb, UID_SZ, uidtb_fail);
  FLUSHTB(usrtb, UNM_SZ, usrtb_fail);
  pwopn = 0;
  _pwcache_setpassent = a_setpassent;
  _pwcache_endpwent = a_endpwent;
  _pwcache_getpwnam = a_getpwnam;
  _pwcache_getpwuid = a_getpwuid;

  return (0);
}

int pwcache_groupdb(int (*a_setgroupent)(int), void (*a_endgrent)(void),
                    struct group *(*a_getgrnam)(const char *),
                    struct group *(*a_getgrgid)(gid_t)) {
  int i;

  /* a_setgroupent and a_endgrent may be NULL */
  if (a_getgrnam == NULL || a_getgrgid == NULL)
    return (-1);

  if (_pwcache_endgrent != NULL)
    (*_pwcache_endgrent)();
  FLUSHTB(gidtb, GID_SZ, gidtb_fail);
  FLUSHTB(grptb, GNM_SZ, grptb_fail);
  gropn = 0;
  _pwcache_setgroupent = a_setgroupent;
  _pwcache_endgrent = a_endgrent;
  _pwcache_getgrnam = a_getgrnam;
  _pwcache_getgrgid = a_getgrgid;

  return (0);
}
