text: /*	$NetBSD: pwcache.c,v 1.31 2010/03/23 20:28:59 drochner Exp $	*/
  
  /*-
   * 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.
   */
  
  #if HAVE_NBTOOL_CONFIG_H
  #include "nbtool_config.h"
  /*
   * XXX Undefine the renames of these functions so that we don't
   * XXX rename the versions found in the host's <pwd.h> by mistake!
   */
  #undef group_from_gid
  #undef user_from_uid
  #endif
  
  #include <sys/cdefs.h>
  #if defined(LIBC_SCCS) && !defined(lint)
  #if 0
  static char sccsid[] = "@(#)cache.c	8.1 (Berkeley) 5/31/93";
  #else
  __RCSID("$NetBSD: pwcache.c,v 1.31 2010/03/23 20:28:59 drochner Exp $");
  #endif
  #endif /* LIBC_SCCS and not lint */
  __FBSDID("$FreeBSD: head/contrib/libc-pwcache/pwcache.c 241731 2012-10-19 12:44:22Z brooks $");
  
  #include "namespace.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>
  
  #define	_DIAGASSERT(x)	assert((x))
  
  #if HAVE_NBTOOL_CONFIG_H
  /* XXX Now, re-apply the renaming that we undid above. */
  #define	group_from_gid	__nbcompat_group_from_gid
  #define	user_from_uid	__nbcompat_user_from_uid
  #endif
  
  #ifdef __weak_alias
  __weak_alias(user_from_uid,_user_from_uid)
  __weak_alias(group_from_gid,_group_from_gid)
  __weak_alias(pwcache_groupdb,_pwcache_groupdb)
  #endif
  
  #if !HAVE_PWCACHE_USERDB || HAVE_NBTOOL_CONFIG_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 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 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 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 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);
  }
  
  
  #ifdef TEST_PWCACHE
  
  struct passwd *
  test_getpwnam(const char *name)
  {
  	static struct passwd foo;
  
  	memset(&foo, 0, sizeof(foo));
  	if (strcmp(name, "toor") == 0) {
  		foo.pw_uid = 666;
  		return &foo;
  	}
  	return (getpwnam(name));
  }
  
  int
  main(int argc, char *argv[])
  {
  	uid_t	u;
  	int	r, i;
  
  	printf("pass 1 (default userdb)\n");
  	for (i = 1; i < argc; i++) {
  		printf("i: %d, pwopn %d usrtb_fail %d usrtb %p\n",
  		    i, pwopn, usrtb_fail, usrtb);
  		r = uid_from_user(argv[i], &u);
  		if (r == -1)
  			printf("  uid_from_user %s: failed\n", argv[i]);
  		else
  			printf("  uid_from_user %s: %d\n", argv[i], u);
  	}
  	printf("pass 1 finish: pwopn %d usrtb_fail %d usrtb %p\n",
  		    pwopn, usrtb_fail, usrtb);
  
  	puts("");
  	printf("pass 2 (replacement userdb)\n");
  	printf("pwcache_userdb returned %d\n",
  	    pwcache_userdb(setpassent, test_getpwnam, getpwuid));
  	printf("pwopn %d usrtb_fail %d usrtb %p\n", pwopn, usrtb_fail, usrtb);
  
  	for (i = 1; i < argc; i++) {
  		printf("i: %d, pwopn %d usrtb_fail %d usrtb %p\n",
  		    i, pwopn, usrtb_fail, usrtb);
  		u = -1;
  		r = uid_from_user(argv[i], &u);
  		if (r == -1)
  			printf("  uid_from_user %s: failed\n", argv[i]);
  		else
  			printf("  uid_from_user %s: %d\n", argv[i], u);
  	}
  	printf("pass 2 finish: pwopn %d usrtb_fail %d usrtb %p\n",
  		    pwopn, usrtb_fail, usrtb);
  
  	puts("");
  	printf("pass 3 (null pointers)\n");
  	printf("pwcache_userdb returned %d\n",
  	    pwcache_userdb(NULL, NULL, NULL));
  
  	return (0);
  }
  #endif	/* TEST_PWCACHE */
  #endif	/* !HAVE_PWCACHE_USERDB */
  