freebsd-dev/lib/libc/gen/getpwent.c

/*
 * Copyright (c) 1988, 1993
 *	The Regents of the University of California.  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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)getpwent.c	8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */

#include <sys/param.h>
#include <fcntl.h>
#include <db.h>
#include <syslog.h>
#include <pwd.h>
#include <utmp.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>

static struct passwd _pw_passwd;	/* password structure */
static DB *_pw_db;			/* password database */
static int _pw_keynum;			/* key counter */
static int _pw_stayopen;		/* keep fd's open */
#ifdef YP
struct _namelist {
	char *name;
	struct _namelist *next;
};
static struct passwd _pw_copy;
struct _pw_cache {
	struct passwd pw_entry;
	struct _namelist *namelist;
	struct _pw_cache *next;
};
static int _pluscnt, _minuscnt;
static struct _pw_cache *_plushead = NULL, *_minushead = NULL;
static void _createcaches(), _freecaches();
static int _yp_enabled;			/* set true when yp enabled */
static int _pw_stepping_yp;		/* set true when stepping thru map */
#endif
static int __hashpw(), __initdb();

static int _havemaster(const char *);
static int _getyppass(struct passwd *, const char *, const char *);
static int _nextyppass(struct passwd *);

struct passwd *
getpwent()
{
	DBT key;
	char bf[sizeof(_pw_keynum) + 1];
	int rv;

	if (!_pw_db && !__initdb())
		return((struct passwd *)NULL);

#ifdef YP
	if(_pw_stepping_yp) {
		_pw_passwd = _pw_copy;
		return (_nextyppass(&_pw_passwd) ? &_pw_passwd : 0);
	}
#endif

tryagain:
	++_pw_keynum;
	bf[0] = _PW_KEYBYNUM;
	bcopy((char *)&_pw_keynum, bf + 1, sizeof(_pw_keynum));
	key.data = (u_char *)bf;
	key.size = sizeof(_pw_keynum) + 1;
	rv = __hashpw(&key);
	if(!rv) return (struct passwd *)NULL;
#ifdef YP
	if(_pw_passwd.pw_name[0] == '+' || _pw_passwd.pw_name[0] == '-') {
		_pw_copy = _pw_passwd;
		return (_nextyppass(&_pw_passwd) ? &_pw_passwd : 0);
	}
#else
	/* Ignore YP password file entries when YP is disabled. */
	if(_pw_passwd.pw_name[0] == '+' || _pw_passwd.pw_name[0] == '-') {
		goto tryagain;
	}
#endif
	return(&_pw_passwd);
}

struct passwd *
getpwnam(name)
	const char *name;
{
	DBT key;
	int len, rval;
	char bf[UT_NAMESIZE + 2];

	if (!_pw_db && !__initdb())
		return((struct passwd *)NULL);

	bf[0] = _PW_KEYBYNAME;
	len = strlen(name);
	bcopy(name, bf + 1, MIN(len, UT_NAMESIZE));
	key.data = (u_char *)bf;
	key.size = len + 1;
	rval = __hashpw(&key);

#ifdef YP
	if (!rval && _yp_enabled)
		rval = _getyppass(&_pw_passwd, name, "passwd.byname");
#endif
	/*
	 * Prevent login attempts when YP is not enabled but YP entries
	 * are in /etc/master.passwd.
	 */
	if (rval && (_pw_passwd.pw_name[0] == '+'||
			_pw_passwd.pw_name[0] == '-')) rval = 0;

	endpwent();
	return(rval ? &_pw_passwd : (struct passwd *)NULL);
}

struct passwd *
#ifdef __STDC__
getpwuid(uid_t uid)
#else
getpwuid(uid)
	int uid;
#endif
{
	DBT key;
	int keyuid, rval;
	char bf[sizeof(keyuid) + 1];

	if (!_pw_db && !__initdb())
		return((struct passwd *)NULL);

	bf[0] = _PW_KEYBYUID;
	keyuid = uid;
	bcopy(&keyuid, bf + 1, sizeof(keyuid));
	key.data = (u_char *)bf;
	key.size = sizeof(keyuid) + 1;
	rval = __hashpw(&key);

#ifdef YP
	if (!rval && _yp_enabled) {
		char ypbuf[16];	/* big enough for 32-bit uids and then some */
		snprintf(ypbuf, sizeof ypbuf, "%u", (unsigned)uid);
		rval = _getyppass(&_pw_passwd, ypbuf, "passwd.byuid");
	}
#endif
	/*
	 * Prevent login attempts when YP is not enabled but YP entries
	 * are in /etc/master.passwd.
	 */
	if (rval && (_pw_passwd.pw_name[0] == '+'||
			_pw_passwd.pw_name[0] == '-')) rval = 0;

	endpwent();
	return(rval ? &_pw_passwd : (struct passwd *)NULL);
}

int
setpassent(stayopen)
	int stayopen;
{
	_pw_keynum = 0;
#ifdef YP
	_pw_stepping_yp = 0;
#endif
	_pw_stayopen = stayopen;
	return(1);
}

int
setpwent()
{
	_pw_keynum = 0;
#ifdef YP
	_pw_stepping_yp = 0;
#endif
	_pw_stayopen = 0;
	return(1);
}

void
endpwent()
{
	_pw_keynum = 0;
#ifdef YP
	_pw_stepping_yp = 0;
#endif
	if (_pw_db) {
		(void)(_pw_db->close)(_pw_db);
		_pw_db = (DB *)NULL;
#ifdef YP
		_freecaches();
#endif
	}
}

static
__initdb()
{
	static int warned;
	char *p;

	p = (geteuid()) ? _PATH_MP_DB : _PATH_SMP_DB;
	_pw_db = dbopen(p, O_RDONLY, 0, DB_HASH, NULL);
	if (_pw_db) {
#ifdef YP
		DBT key, data;
		char buf[] = { _PW_KEYYPENABLED };
		key.data = buf;
		key.size = 1;
		if ((_pw_db->get)(_pw_db, &key, &data, 0)) {
			_yp_enabled = 0;
		} else {
			_yp_enabled = (int)*((char *)data.data) - 2;
			_createcaches();
		}
#endif
		return(1);
	}
	if (!warned)
		syslog(LOG_ERR, "%s: %m", p);
	return(0);
}

static
__hashpw(key)
	DBT *key;
{
	register char *p, *t;
	static u_int max;
	static char *line;
	DBT data;

	if ((_pw_db->get)(_pw_db, key, &data, 0))
		return(0);
	p = (char *)data.data;
	if (data.size > max && !(line = realloc(line, max += 1024)))
		return(0);

	t = line;
#define	EXPAND(e)	e = t; while (*t++ = *p++);
	EXPAND(_pw_passwd.pw_name);
	EXPAND(_pw_passwd.pw_passwd);
	bcopy(p, (char *)&_pw_passwd.pw_uid, sizeof(int));
	p += sizeof(int);
	bcopy(p, (char *)&_pw_passwd.pw_gid, sizeof(int));
	p += sizeof(int);
	bcopy(p, (char *)&_pw_passwd.pw_change, sizeof(time_t));
	p += sizeof(time_t);
	EXPAND(_pw_passwd.pw_class);
	EXPAND(_pw_passwd.pw_gecos);
	EXPAND(_pw_passwd.pw_dir);
	EXPAND(_pw_passwd.pw_shell);
	bcopy(p, (char *)&_pw_passwd.pw_expire, sizeof(time_t));
	p += sizeof(time_t);
	bcopy(p, (char *)&_pw_passwd.pw_fields, sizeof _pw_passwd.pw_fields);
	p += sizeof _pw_passwd.pw_fields;
	return(1);
}

#ifdef YP
/*
 * Build special +@netgroup and -@netgroup caches. We also handle ordinary
 * +user/-user entries, *and* +@group/-@group entries, which are special
 * cases of the +@netgroup/-@netgroup substitutions: if we can't find
 * netgroup 'foo', we look for a regular user group called 'foo' and
 * match against that instead. The netgroup takes precedence since the
 * +group/-group support is basically just a hack to make Justin T. Gibbs
 * happy. :) Sorting out all the funny business here lets us have a
 * yp_enabled flag with a simple on or off value instead of the somewhat
 * bogus setup we had before.
 *
 * We cache everything here in one shot so that we only have to scan
 * each netgroup/group once. The alternative is to use innetgr() inside the
 * NIS lookup functions, which would make retrieving the whole password
 * database though getpwent() very slow. +user/-user entries are treated
 * like @groups/@netgroups with only one member.
 */
#include <grp.h>
static void
_createcaches()
{
	DBT key, data;
	int i;
	char bf[UT_NAMESIZE + 2];
	char entry[UT_NAMESIZE];
	struct _pw_cache *p, *m;
	struct _namelist *n, *namehead;
	char *user, *host, *domain;
	struct group *grp;

	/*
	 * Assume that the database has already been initialized
	 * but be paranoid and check that YP is in fact enabled.
	 */

	if (!_yp_enabled)
		return;
	/*
	 * For the plus list, we have to store both the linked list of
	 * names and the +entries from the password database so we can
	 * do the substitution later if we find a match.
	 */
	bf[0] = _PW_KEYPLUSCNT;
	key.data = (u_char*)bf;
	key.size = 1;
	if (!(_pw_db->get)(_pw_db, &key, &data, 0)) {
		_pluscnt = (int)*((char *)data.data);
		for (i = 0; i < _pluscnt; i++) {
			bf[0] = _PW_KEYPLUSBYNUM;
			bcopy(&i, bf + 1, sizeof(i) + 1);
			key.size = (sizeof(i)) + 1;
			if (__hashpw(&key)) {
				p = (struct _pw_cache *)malloc(sizeof (struct _pw_cache));
				if (strlen(_pw_passwd.pw_name) > 2 && _pw_passwd.pw_name[1] == '@') {
					setnetgrent(_pw_passwd.pw_name+2);
					namehead = NULL;
					while(getnetgrent(&host, &user, &domain)) {
						n = (struct _namelist *)malloc(sizeof (struct _namelist));
						n->name = strdup(user);
						n->next = namehead;
						namehead = n;
					}
					/* 
					 * If netgroup 'foo' doesn't exist,
					 * try group 'foo' instead.
					 */
					if (namehead == NULL && (grp = getgrnam(_pw_passwd.pw_name+2)) != NULL) {
						while(*grp->gr_mem) {
							n = (struct _namelist *)malloc(sizeof (struct _namelist));
							n->name = strdup(*grp->gr_mem);
							n->next = namehead;
							namehead = n;
							grp->gr_mem++;
						}
					}
				} else {
					if (_pw_passwd.pw_name[1] != '@') {
						namehead = (struct _namelist *)malloc(sizeof (struct _namelist));
						namehead->name = strdup(_pw_passwd.pw_name+1);
						namehead->next = NULL;
					}
				}
				p->namelist = namehead;
				p->pw_entry.pw_name = strdup(_pw_passwd.pw_name);
				p->pw_entry.pw_passwd = strdup(_pw_passwd.pw_passwd);
				p->pw_entry.pw_uid = _pw_passwd.pw_uid;
				p->pw_entry.pw_gid = _pw_passwd.pw_gid;
				p->pw_entry.pw_expire = _pw_passwd.pw_expire;
				p->pw_entry.pw_change = _pw_passwd.pw_change;
				p->pw_entry.pw_class = strdup(_pw_passwd.pw_class);
				p->pw_entry.pw_gecos = strdup(_pw_passwd.pw_gecos);
				p->pw_entry.pw_dir = strdup(_pw_passwd.pw_dir);
				p->pw_entry.pw_shell = strdup(_pw_passwd.pw_shell);
				p->pw_entry.pw_fields = _pw_passwd.pw_fields;
				p->next = _plushead;
				_plushead = p;
			}
		}
	}

	/*
	 * All we need for the minuslist is the usernames.
	 * The actual -entries data can be ignored since no substitution
	 * will be done: anybody on the minus list is treated like a
	 * non-person.
	 */
	bf[0] = _PW_KEYMINUSCNT;
	key.data = (u_char*)bf;
	key.size = 1;
	if (!(_pw_db->get)(_pw_db, &key, &data, 0)) {
		_minuscnt = (int)*((char *)data.data);
		for (i = 0; i < _minuscnt; i++) {
			bf[0] = _PW_KEYMINUSBYNUM;
			bcopy(&i, bf + 1, sizeof(i) + 1);
			key.size = (sizeof(i)) + 1;
			if (__hashpw(&key)) {
				m = (struct _pw_cache *)malloc(sizeof (struct _pw_cache));
				if (strlen (_pw_passwd.pw_name) > 2 && _pw_passwd.pw_name[1] == '@') {
					namehead = NULL;
					setnetgrent(_pw_passwd.pw_name+2);
					while(getnetgrent(&host, &user, &domain)) {
						n = (struct _namelist *)malloc(sizeof (struct _namelist));
						n->name = strdup(user);
						n->next = namehead;
						namehead = n;
					}
					/* 
					 * If netgroup 'foo' doesn't exist,
					 * try group 'foo' instead.
					 */
					if (namehead == NULL && (grp = getgrnam(_pw_passwd.pw_name+2)) != NULL) {
						while(*grp->gr_mem) {
							n = (struct _namelist *)malloc(sizeof (struct _namelist));
							n->name = strdup(*grp->gr_mem);
							n->next = namehead;
							namehead = n;
							grp->gr_mem++;
						}
					}
				} else {
					if (_pw_passwd.pw_name[1] != '@') {
						namehead = (struct _namelist *)malloc(sizeof (struct _namelist));
						namehead->name = strdup(_pw_passwd.pw_name+1);
						namehead->next = NULL;
					}
				}
				m->namelist = namehead;
				m->next = _minushead;
				_minushead = m;
			}
		}
	}
	endgrent();
	endnetgrent();
}

/*
 * Free the +@netgroup/-@netgroup caches. Should be called
 * from endpwent(). We have to blow away both the list of
 * netgroups and the attached linked lists of usernames.
 */
static void
_freecaches()
{
struct _pw_cache *p, *m;
struct _namelist *n;

	while (_plushead) {
			while(_plushead->namelist) {
				n = _plushead->namelist->next;
				free(_plushead->namelist);
				_plushead->namelist = n;
			}
		p = _plushead->next;
		free(_plushead);
		_plushead = p;
	}

	while(_minushead) {
			while(_minushead->namelist) {
				n = _minushead->namelist->next;
				free(_minushead->namelist);
				_minushead->namelist = n;
			}
		m = _minushead->next;
		free(_minushead);
		_minushead = m;
	}
	_pluscnt = _minuscnt = 0;
}

static void
_pw_breakout_yp(struct passwd *pw, char *result, int master)
{
	char *s;

	s = strsep(&result, ":"); /* name */
	if(!(pw->pw_fields & _PWF_NAME) || (pw->pw_name[0] == '+')) {
		pw->pw_name = s;
		pw->pw_fields |= _PWF_NAME;
	}

	s = strsep(&result, ":"); /* password */
	if(!(pw->pw_fields & _PWF_PASSWD)) {
		pw->pw_passwd = s;
		pw->pw_fields |= _PWF_PASSWD;
	}

	s = strsep(&result, ":"); /* uid */
	if(!(pw->pw_fields & _PWF_UID)) {
		pw->pw_uid = atoi(s);
		pw->pw_fields |= _PWF_UID;
	}

	s = strsep(&result, ":"); /* gid */
	if(!(pw->pw_fields & _PWF_GID))  {
		pw->pw_gid = atoi(s);
		pw->pw_fields |= _PWF_GID;
	}

	if (master) {
		s = strsep(&result, ":"); /* class */
		if(!(pw->pw_fields & _PWF_CLASS))  {
			pw->pw_class = s;
			pw->pw_fields |= _PWF_CLASS;
		}

		s = strsep(&result, ":"); /* change */
		if(!(pw->pw_fields & _PWF_CHANGE))  {
			pw->pw_change = atol(s);
			pw->pw_fields |= _PWF_CHANGE;
		}

		s = strsep(&result, ":"); /* expire */
		if(!(pw->pw_fields & _PWF_EXPIRE))  {
			pw->pw_expire = atol(s);
			pw->pw_fields |= _PWF_EXPIRE;
		}
	}

	s = strsep(&result, ":"); /* gecos */
	if(!(pw->pw_fields & _PWF_GECOS)) {
		pw->pw_gecos = s;
		pw->pw_fields |= _PWF_GECOS;
	}

	s = strsep(&result, ":"); /* dir */
	if(!(pw->pw_fields & _PWF_DIR)) {
		pw->pw_dir = s;
		pw->pw_fields |= _PWF_DIR;
	}

	s = strsep(&result, ":"); /* shell */
	if(!(pw->pw_fields & _PWF_SHELL)) {
		pw->pw_shell = s;
		pw->pw_fields |= _PWF_SHELL;
	}
}

static char *_pw_yp_domain;

static int
_havemaster(const char *_pw_yp_domain)
{
	char *result;
	static char *key;
	int resultlen;
	static int keylen;
	
	if (yp_first(_pw_yp_domain, "master.passwd.byname",
		      &key, &keylen, &result, &resultlen))
		return 0;
	
	return 1;
}

static int
_getyppass(struct passwd *pw, const char *name, const char *map)
{
	char *result, *s;
	static char resultbuf[1024];
	int resultlen;
	char mastermap[1024];
	int gotmaster = 0;
	struct _pw_cache *m, *p;
	struct _namelist *n;

	if(!_pw_yp_domain) {
		if(yp_get_default_domain(&_pw_yp_domain))
		  return 0;
	}

	sprintf(mastermap,"%s",map);

	/* Don't even bother with this if we aren't root. */
	if (!geteuid())
		if (_havemaster(_pw_yp_domain)) {
			sprintf(mastermap,"master.%s", map);
			gotmaster++;
		}

	if(yp_match(_pw_yp_domain, &mastermap, name, strlen(name), 
		    &result, &resultlen))
		return 0;

	s = strchr(result, '\n');
	if(s) *s = '\0';

	if(resultlen >= sizeof resultbuf) return 0;
	strcpy(resultbuf, result);
	s = strsep(&result,":");
	_pw_passwd.pw_fields = 0;
	if (_minuscnt && _minushead) {
		m = _minushead;
		while (m) {
			n = m->namelist;
			while (n) {
				if (!strcmp(n->name, s) || *n->name == '\0') {
					free(result);
					return (0);
				}
				n = n->next;
			}
			m = m->next;
		}
	}
	if (_pluscnt && _plushead) {
		p = _plushead;
		while (p) {
			n = p->namelist;
			while (n) {
				if (!strcmp(n->name, s) || *n->name == '\0')
					bcopy((char *)&p->pw_entry,
					(char *)&_pw_passwd, sizeof(p->pw_entry));
				n = n->next;
			}
			p = p->next;
		}
	}
	free(result);
	result = resultbuf;
	_pw_breakout_yp(pw, resultbuf, gotmaster);

	return 1;
}

static int
_nextyppass(struct passwd *pw)
{
	static char *key, *s;
	static int keylen;
	char *lastkey, *result;
	static char resultbuf[1024];
	int resultlen;
	int rv;
	char *map = "passwd.byname";
	int gotmaster = 0;
	struct _pw_cache *m, *p;
	struct _namelist *n;

	if(!_pw_yp_domain) {
		if(yp_get_default_domain(&_pw_yp_domain))
		  return 0;
	}

	/* Don't even bother with this if we aren't root. */
	if (!geteuid())
		if(_havemaster(_pw_yp_domain)) {
			map = "master.passwd.byname";
			gotmaster++;
		}

	if(!_pw_stepping_yp) {
		if(key) free(key);
			rv = yp_first(_pw_yp_domain, map,
				      &key, &keylen, &result, &resultlen);
		if(rv) {
			return 0;
		}
		_pw_stepping_yp = 1;
		goto unpack;
	} else {
tryagain:
		lastkey = key;
			rv = yp_next(_pw_yp_domain, map, key, keylen,
			     &key, &keylen, &result, &resultlen);
		free(lastkey);
unpack:
		if(rv) {
			_pw_stepping_yp = 0;
			return 0;
		}

		if(resultlen > sizeof(resultbuf)) {
			free(result);
			goto tryagain;
		}

		strcpy(resultbuf, result);
		s = strsep(&result,":");
		_pw_passwd.pw_fields = 0;
		if (_minuscnt && _minushead) {
			m = _minushead;
			while (m) {
				n = m->namelist;
				while (n) {
					if (!strcmp(n->name, s) || *n->name == '\0') {
						free(result);
						goto tryagain;
					}
					n = n->next;
				}
				m = m->next;
			}
		}
		if (_pluscnt && _plushead) {
			p = _plushead;
			while (p) {
				n = p->namelist;
				while (n) {
					if (!strcmp(n->name, s) || *n->name == '\0')
						bcopy((char *)&p->pw_entry,
						(char*)&_pw_passwd, sizeof(p->pw_entry));
					n = n->next;
				}
				p = p->next;
			}
		}
		free(result);
		if(result = strchr(resultbuf, '\n')) *result = '\0';
		_pw_breakout_yp(pw, resultbuf, gotmaster);
	}
	return 1;
}
		
#endif /* YP */