text: /* $OpenBSD: user.c,v 1.81 2011/04/16 07:41:08 sobrado Exp $ */
  /* $NetBSD: user.c,v 1.69 2003/04/14 17:40:07 agc Exp $ */
  
  /*
   * Copyright (c) 1999 Alistair G. Crooks.  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 Alistair G. Crooks.
   * 4. The name of the author may not be used to endorse or promote
   *    products derived from this software without specific prior written
   *    permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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/param.h>
  #include <sys/stat.h>
  
  #include <ctype.h>
  #include <dirent.h>
  #include <err.h>
  #include <fcntl.h>
  #include <grp.h>
  #ifdef EXTENSIONS
  #include <login_cap.h>
  #endif
  #include <paths.h>
  #include <pwd.h>
  #include <stdarg.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <syslog.h>
  #include <time.h>
  #include <unistd.h>
  #include <util.h>
  
  #include "defs.h"
  #include "usermgmt.h"
  
  
  /* this struct describes a uid range */
  typedef struct range_t {
  	uid_t	r_from;		/* low uid */
  	uid_t	r_to;		/* high uid */
  } range_t;
  
  /* this struct encapsulates the user information */
  typedef struct user_t {
  	int		u_flags;		/* see below */
  	uid_t		u_uid;			/* uid of user */
  	char	       *u_password;		/* encrypted password */
  	char	       *u_comment;		/* comment field */
  	char	       *u_home;		/* home directory */
  	char	       *u_primgrp;		/* primary group */
  	int		u_groupc;		/* # of secondary groups */
  	const char     *u_groupv[NGROUPS_MAX];	/* secondary groups */
  	char	       *u_shell;		/* user's shell */
  	char	       *u_basedir;		/* base directory for home */
  	char	       *u_expire;		/* when account will expire */
  	char	       *u_inactive;		/* when password will expire */
  	char	       *u_skeldir;		/* directory for startup files */
  	char	       *u_class;		/* login class */
  	unsigned int	u_rsize;		/* size of range array */
  	unsigned int	u_rc;			/* # of ranges */
  	range_t	       *u_rv;			/* the ranges */
  	unsigned int	u_defrc;		/* # of ranges in defaults */
  	int		u_preserve;		/* preserve uids on deletion */
  } user_t;
  
  /* flags for which fields of the user_t replace the passwd entry */
  enum {
  	F_COMMENT	= 0x0001,
  	F_DUPUID	= 0x0002,
  	F_EXPIRE	= 0x0004,
  	F_GROUP		= 0x0008,
  	F_HOMEDIR	= 0x0010,
  	F_MKDIR		= 0x0020,
  	F_INACTIVE	= 0x0040,
  	F_PASSWORD	= 0x0080,
  	F_SECGROUP	= 0x0100,
  	F_SHELL		= 0x0200,
  	F_UID		= 0x0400,
  	F_USERNAME	= 0x0800,
  	F_CLASS		= 0x1000
  };
  
  #define CONFFILE	"/etc/usermgmt.conf"
  
  #ifndef DEF_GROUP
  #define DEF_GROUP	"users"
  #endif
  
  #ifndef DEF_BASEDIR
  #define DEF_BASEDIR	"/home"
  #endif
  
  #ifndef DEF_SKELDIR
  #define DEF_SKELDIR	"/etc/skel"
  #endif
  
  #ifndef DEF_SHELL
  #define DEF_SHELL	_PATH_KSHELL
  #endif
  
  #ifndef DEF_COMMENT
  #define DEF_COMMENT	""
  #endif
  
  #ifndef DEF_LOWUID
  #define DEF_LOWUID	1000
  #endif
  
  #ifndef DEF_HIGHUID
  #define DEF_HIGHUID	60000
  #endif
  
  #ifndef DEF_INACTIVE
  #define DEF_INACTIVE	0
  #endif
  
  #ifndef DEF_EXPIRE
  #define DEF_EXPIRE	NULL
  #endif
  
  #ifndef DEF_CLASS
  #define DEF_CLASS	""
  #endif
  
  #ifndef WAITSECS
  #define WAITSECS	10
  #endif
  
  #ifndef NOBODY_UID
  #define NOBODY_UID	32767
  #endif
  
  /* some useful constants */
  enum {
  	MaxShellNameLen = 256,
  	MaxFileNameLen = MAXPATHLEN,
  	MaxUserNameLen = _PW_NAME_LEN,
  	MaxCommandLen = 2048,
  	PasswordLength = _PASSWORD_LEN,
  
  	DES_Len = 13,
  
  	LowGid = DEF_LOWUID,
  	HighGid = DEF_HIGHUID
  };
  
  /* Full paths of programs used here */
  #define CHMOD		"/bin/chmod"
  #define CHOWN		"/sbin/chown"
  #define MKDIR		"/bin/mkdir"
  #define MV		"/bin/mv"
  #define NOLOGIN		"/sbin/nologin"
  #define PAX		"/bin/pax"
  #define RM		"/bin/rm"
  
  #define UNSET_INACTIVE	"Null (unset)"
  #define UNSET_EXPIRY	"Null (unset)"
  
  static int asystem(const char *fmt, ...)
  	__attribute__((__format__(__printf__, 1, 2)));
  
  static int	verbose;
  
  /* if *cpp is non-null, free it, then assign `n' chars of `s' to it */
  static void
  memsave(char **cpp, const char *s, size_t n)
  {
  	if (*cpp != NULL) {
  		FREE(*cpp);
  	}
  	NEWARRAY(char, *cpp, n + 1, exit(1));
  	(void) memcpy(*cpp, s, n);
  	(*cpp)[n] = '\0';
  }
  
  /* a replacement for system(3) */
  static int
  asystem(const char *fmt, ...)
  {
  	va_list	vp;
  	char	buf[MaxCommandLen];
  	int	ret;
  
  	va_start(vp, fmt);
  	(void) vsnprintf(buf, sizeof(buf), fmt, vp);
  	va_end(vp);
  	if (verbose) {
  		(void) printf("Command: %s\n", buf);
  	}
  	if ((ret = system(buf)) != 0) {
  		warnx("[Warning] can't system `%s'", buf);
  	}
  	return ret;
  }
  
  /* remove a users home directory, returning 1 for success (ie, no problems encountered) */
  static int
  removehomedir(const char *user, uid_t uid, const char *dir)
  {
  	struct stat st;
  
  	/* userid not root? */
  	if (uid == 0) {
  		warnx("Not deleting home directory `%s'; userid is 0", dir);
  		return 0;
  	}
  
  	/* directory exists (and is a directory!) */
  	if (stat(dir, &st) < 0) {
  		warnx("Home directory `%s' doesn't exist", dir);
  		return 0;
  	}
  	if (!S_ISDIR(st.st_mode)) {
  		warnx("Home directory `%s' is not a directory", dir);
  		return 0;
  	}
  
  	/* userid matches directory owner? */
  	if (st.st_uid != uid) {
  		warnx("User `%s' doesn't own directory `%s', not removed",
  		    user, dir);
  		return 0;
  	}
  
  	(void) seteuid(uid);
  	/* we add the "|| true" to keep asystem() quiet if there is a non-zero exit status. */
  	(void) asystem("%s -rf %s > /dev/null 2>&1 || true", RM, dir);
  	(void) seteuid(0);
  	if (rmdir(dir) < 0) {
  		warnx("Unable to remove all files in `%s'", dir);
  		return 0;
  	}
  	return 1;
  }
  
  /* return 1 if all of `s' is numeric */
  static int
  is_number(char *s)
  {
  	for ( ; *s ; s++) {
  		if (!isdigit((unsigned char) *s)) {
  			return 0;
  		}
  	}
  	return 1;
  }
  
  /*
   * check that the effective uid is 0 - called from funcs which will
   * modify data and config files.
   */
  static void
  checkeuid(void)
  {
  	if (geteuid() != 0) {
  		errx(EXIT_FAILURE, "Program must be run as root");
  	}
  }
  
  /* copy any dot files into the user's home directory */
  static int
  copydotfiles(char *skeldir, uid_t uid, gid_t gid, char *dir)
  {
  	struct dirent	*dp;
  	DIR		*dirp;
  	int		n;
  
  	if ((dirp = opendir(skeldir)) == NULL) {
  		warn("can't open source . files dir `%s'", skeldir);
  		return 0;
  	}
  	for (n = 0; (dp = readdir(dirp)) != NULL && n == 0 ; ) {
  		if (strcmp(dp->d_name, ".") == 0 ||
  		    strcmp(dp->d_name, "..") == 0) {
  			continue;
  		}
  		n = 1;
  	}
  	(void) closedir(dirp);
  	if (n == 0) {
  		warnx("No \"dot\" initialisation files found");
  	} else {
  		(void) asystem("cd %s && %s -rw -pe %s . %s",
  				skeldir, PAX, (verbose) ? "-v" : "", dir);
  	}
  	(void) asystem("%s -R -P %u:%u %s", CHOWN, uid, gid, dir);
  	(void) asystem("%s -R u+w %s", CHMOD, dir);
  	return n;
  }
  
  /* create a group entry with gid `gid' */
  static int
  creategid(char *group, gid_t gid, const char *name)
  {
  	struct stat	st;
  	FILE		*from;
  	FILE		*to;
  	char		*buf;
  	char		f[MaxFileNameLen];
  	int		fd, ret;
  	int		wroteit = 0;
  	size_t		len;
  
  	if (getgrnam(group) != NULL) {
  		warnx("group `%s' already exists", group);
  		return 0;
  	}
  	if ((from = fopen(_PATH_GROUP, "r")) == NULL) {
  		warn("can't create gid for `%s': can't open `%s'", group,
  		    _PATH_GROUP);
  		return 0;
  	}
  	if (flock(fileno(from), LOCK_EX | LOCK_NB) < 0) {
  		warn("can't lock `%s'", _PATH_GROUP);
  	}
  	(void) fstat(fileno(from), &st);
  	(void) snprintf(f, sizeof(f), "%s.XXXXXXXX", _PATH_GROUP);
  	if ((fd = mkstemp(f)) < 0) {
  		(void) fclose(from);
  		warn("can't create gid: mkstemp failed");
  		return 0;
  	}
  	if ((to = fdopen(fd, "w")) == NULL) {
  		(void) fclose(from);
  		(void) close(fd);
  		(void) unlink(f);
  		warn("can't create gid: fdopen `%s' failed", f);
  		return 0;
  	}
  	while ((buf = fgetln(from, &len)) != NULL && len > 0) {
  		ret = 0;
  		if (buf[0] == '+' && wroteit == 0) {
  			ret = fprintf(to, "%s:*:%u:%s\n", group, gid, name);
  			wroteit = 1;
  		}
  		if (ret == -1 ||
  		    fprintf(to, "%*.*s", (int)len, (int)len, buf) != len) {
  			(void) fclose(from);
  			(void) fclose(to);
  			(void) unlink(f);
  			warn("can't create gid: short write to `%s'", f);
  			return 0;
  		}
  	}
  	ret = 0;
  	if (wroteit == 0)
  		ret = fprintf(to, "%s:*:%u:%s\n", group, gid, name);
  	(void) fclose(from);
  	if (fclose(to) == EOF || ret == -1) {
  		(void) unlink(f);
  		warn("can't create gid: short write to `%s'", f);
  		return 0;
  	}
  	if (rename(f, _PATH_GROUP) < 0) {
  		(void) unlink(f);
  		warn("can't create gid: can't rename `%s' to `%s'", f,
  		    _PATH_GROUP);
  		return 0;
  	}
  	(void) chmod(_PATH_GROUP, st.st_mode & 07777);
  	syslog(LOG_INFO, "new group added: name=%s, gid=%d", group, gid);
  	return 1;
  }
  
  /* modify the group entry with name `group' to be newent */
  static int
  modify_gid(char *group, char *newent)
  {
  	struct stat	st;
  	FILE		*from;
  	FILE		*to;
  	char		buf[LINE_MAX];
  	char		f[MaxFileNameLen];
  	char		*colon;
  	int		groupc;
  	int		entc;
  	int		fd;
  	int		cc;
  
  	if ((from = fopen(_PATH_GROUP, "r")) == NULL) {
  		warn("can't modify gid for `%s': can't open `%s'", group,
  		    _PATH_GROUP);
  		return 0;
  	}
  	if (flock(fileno(from), LOCK_EX | LOCK_NB) < 0) {
  		warn("can't lock `%s'", _PATH_GROUP);
  	}
  	(void) fstat(fileno(from), &st);
  	(void) snprintf(f, sizeof(f), "%s.XXXXXXXX", _PATH_GROUP);
  	if ((fd = mkstemp(f)) < 0) {
  		(void) fclose(from);
  		warn("can't modify gid: mkstemp failed");
  		return 0;
  	}
  	if ((to = fdopen(fd, "w")) == NULL) {
  		(void) fclose(from);
  		(void) close(fd);
  		(void) unlink(f);
  		warn("can't modify gid: fdopen `%s' failed", f);
  		return 0;
  	}
  	groupc = strlen(group);
  	while (fgets(buf, sizeof(buf), from) != NULL) {
  		cc = strlen(buf);
  		if (cc > 0 && buf[cc - 1] != '\n' && !feof(from)) {
  			while (fgetc(from) != '\n' && !feof(from))
  				cc++;
  			warnx("%s: line `%s' too long (%d bytes), skipping",
  			    _PATH_GROUP, buf, cc);
  			continue;
  		}
  		if ((colon = strchr(buf, ':')) == NULL) {
  			/*
  			 * The only valid entry with no column is the all-YP
  			 * line.
  			 */
  			if (strcmp(buf, "+\n") != 0) {
  				warnx("badly formed entry `%.*s'", cc - 1, buf);
  				continue;
  			}
  		} else {
  			entc = (int)(colon - buf);
  			if (entc == groupc && strncmp(group, buf, entc) == 0) {
  				if (newent == NULL) {
  					continue;
  				} else {
  					cc = strlcpy(buf, newent, sizeof(buf));
  					if (cc >= sizeof(buf)) {
  						warnx("group `%s' entry too long",
  						    newent);
  						return (0);
  					}
  				}
  			}
  		}
  		if (fwrite(buf, cc, 1, to) != 1) {
  			(void) fclose(from);
  			(void) fclose(to);
  			(void) unlink(f);
  			warn("can't modify gid: short write to `%s'", f);
  			return 0;
  		}
  	}
  	(void) fclose(from);
  	if (fclose(to) == EOF) {
  		(void) unlink(f);
  		warn("can't modify gid: short write to `%s'", f);
  		return 0;
  	}
  	if (rename(f, _PATH_GROUP) < 0) {
  		(void) unlink(f);
  		warn("can't modify gid: can't rename `%s' to `%s'", f, _PATH_GROUP);
  		return 0;
  	}
  	(void) chmod(_PATH_GROUP, st.st_mode & 07777);
  	if (newent == NULL) {
  		syslog(LOG_INFO, "group deleted: name=%s", group);
  	} else {
  		syslog(LOG_INFO, "group information modified: name=%s", group);
  	}
  	return 1;
  }
  
  /* modify the group entries for all `groups', by adding `user' */
  static int
  append_group(char *user, int ngroups, const char **groups)
  {
  	struct group	*grp;
  	struct stat	st;
  	FILE		*from;
  	FILE		*to;
  	char		buf[LINE_MAX];
  	char		f[MaxFileNameLen];
  	char		*colon;
  	int		fd;
  	int		cc;
  	int		i;
  	int		j;
  
  	for (i = 0 ; i < ngroups ; i++) {
  		if ((grp = getgrnam(groups[i])) == NULL) {
  			warnx("can't append group `%s' for user `%s'",
  			    groups[i], user);
  		} else {
  			for (j = 0 ; grp->gr_mem[j] ; j++) {
  				if (strcmp(user, grp->gr_mem[j]) == 0) {
  					/* already in it */
  					groups[i] = "";
  				}
  			}
  		}
  	}
  	if ((from = fopen(_PATH_GROUP, "r")) == NULL) {
  		warn("can't append group for `%s': can't open `%s'", user,
  		    _PATH_GROUP);
  		return 0;
  	}
  	if (flock(fileno(from), LOCK_EX | LOCK_NB) < 0) {
  		warn("can't lock `%s'", _PATH_GROUP);
  	}
  	(void) fstat(fileno(from), &st);
  	(void) snprintf(f, sizeof(f), "%s.XXXXXXXX", _PATH_GROUP);
  	if ((fd = mkstemp(f)) < 0) {
  		(void) fclose(from);
  		warn("can't append group: mkstemp failed");
  		return 0;
  	}
  	if ((to = fdopen(fd, "w")) == NULL) {
  		(void) fclose(from);
  		(void) close(fd);
  		(void) unlink(f);
  		warn("can't append group: fdopen `%s' failed", f);
  		return 0;
  	}
  	while (fgets(buf, sizeof(buf), from) != NULL) {
  		cc = strlen(buf);
  		if (cc > 0 && buf[cc - 1] != '\n' && !feof(from)) {
  			while (fgetc(from) != '\n' && !feof(from))
  				cc++;
  			warnx("%s: line `%s' too long (%d bytes), skipping",
  			    _PATH_GROUP, buf, cc);
  			continue;
  		}
  		if ((colon = strchr(buf, ':')) == NULL) {
  			warnx("badly formed entry `%s'", buf);
  			continue;
  		}
  		for (i = 0 ; i < ngroups ; i++) {
  			j = (int)(colon - buf);
  			if (strncmp(groups[i], buf, j) == 0 &&
  			    groups[i][j] == '\0') {
  				while (isspace(buf[cc - 1]))
  					cc--;
  				buf[(j = cc)] = '\0';
  				if (buf[strlen(buf) - 1] != ':')
  					strlcat(buf, ",", sizeof(buf));
  				cc = strlcat(buf, user, sizeof(buf)) + 1;
  				if (cc >= sizeof(buf)) {
  					warnx("Warning: group `%s' would "
  					    "become too long, not modifying",
  					    groups[i]);
  					cc = j + 1;
  				}
  				buf[cc - 1] = '\n';
  				buf[cc] = '\0';
  			}
  		}
  		if (fwrite(buf, cc, 1, to) != 1) {
  			(void) fclose(from);
  			(void) fclose(to);
  			(void) unlink(f);
  			warn("can't append group: short write to `%s'", f);
  			return 0;
  		}
  	}
  	(void) fclose(from);
  	if (fclose(to) == EOF) {
  		(void) unlink(f);
  		warn("can't append group: short write to `%s'", f);
  		return 0;
  	}
  	if (rename(f, _PATH_GROUP) < 0) {
  		(void) unlink(f);
  		warn("can't append group: can't rename `%s' to `%s'", f, _PATH_GROUP);
  		return 0;
  	}
  	(void) chmod(_PATH_GROUP, st.st_mode & 07777);
  	return 1;
  }
  
  /* return 1 if `login' is a valid login name */
  static int
  valid_login(char *login_name)
  {
  	unsigned char	*cp;
  
  	/* The first character cannot be a hyphen */
  	if (*login_name == '-')
  		return 0;
  
  	for (cp = login_name ; *cp ; cp++) {
  		/* We allow '$' as the last character for samba */
  		if (!isalnum(*cp) && *cp != '.' && *cp != '_' && *cp != '-' &&
  		    !(*cp == '$' && *(cp + 1) == '\0')) {
  			return 0;
  		}
  	}
  	if ((char *)cp - login_name > MaxUserNameLen)
  		return 0;
  	return 1;
  }
  
  /* return 1 if `group' is a valid group name */
  static int
  valid_group(char *group)
  {
  	unsigned char	*cp;
  
  	for (cp = group ; *cp ; cp++) {
  		if (!isalnum(*cp) && *cp != '.' && *cp != '_' && *cp != '-') {
  			return 0;
  		}
  	}
  	if ((char *)cp - group > MaxUserNameLen)
  		return 0;
  	return 1;
  }
  
  #ifdef EXTENSIONS
  /* return 1 if `class' exists */
  static int
  valid_class(char *class)
  {
  	login_cap_t *lc;
  
  	if ((lc = login_getclass(class)) != NULL)
  		login_close(lc);
  	return lc != NULL;
  }
  #endif
  
  /* find the next gid in the range lo .. hi */
  static int
  getnextgid(uid_t *gidp, uid_t lo, uid_t hi)
  {
  	for (*gidp = lo ; *gidp < hi ; *gidp += 1) {
  		if (getgrgid((gid_t)*gidp) == NULL) {
  			return 1;
  		}
  	}
  	return 0;
  }
  
  #ifdef EXTENSIONS
  /* save a range of uids */
  static int
  save_range(user_t *up, char *cp)
  {
  	int	from;
  	int	to;
  	int	i;
  
  	if (up->u_rsize == 0) {
  		up->u_rsize = 32;
  		NEWARRAY(range_t, up->u_rv, up->u_rsize, return(0));
  	} else if (up->u_rc == up->u_rsize) {
  		up->u_rsize *= 2;
  		RENEW(range_t, up->u_rv, up->u_rsize, return(0));
  	}
  	if (up->u_rv && sscanf(cp, "%d..%d", &from, &to) == 2) {
  		for (i = up->u_defrc ; i < up->u_rc ; i++) {
  			if (up->u_rv[i].r_from == from && up->u_rv[i].r_to == to) {
  				break;
  			}
  		}
  		if (i == up->u_rc) {
  			up->u_rv[up->u_rc].r_from = from;
  			up->u_rv[up->u_rc].r_to = to;
  			up->u_rc += 1;
  		}
  	} else {
  		warnx("Bad range `%s'", cp);
  		return 0;
  	}
  	return 1;
  }
  #endif
  
  /* set the defaults in the defaults file */
  static int
  setdefaults(user_t *up)
  {
  	char	template[MaxFileNameLen];
  	FILE	*fp;
  	int	ret;
  	int	fd;
  #ifdef EXTENSIONS
  	int	i;
  #endif
  
  	(void) snprintf(template, sizeof(template), "%s.XXXXXXXX", CONFFILE);
  	if ((fd = mkstemp(template)) < 0) {
  		warnx("can't mkstemp `%s' for writing", CONFFILE);
  		return 0;
  	}
  	if ((fp = fdopen(fd, "w")) == NULL) {
  		warn("can't fdopen `%s' for writing", CONFFILE);
  		return 0;
  	}
  	ret = 1;
  	if (fprintf(fp, "group\t\t%s\n", up->u_primgrp) <= 0 ||
  	    fprintf(fp, "base_dir\t%s\n", up->u_basedir) <= 0 ||
  	    fprintf(fp, "skel_dir\t%s\n", up->u_skeldir) <= 0 ||
  	    fprintf(fp, "shell\t\t%s\n", up->u_shell) <= 0 ||
  #ifdef EXTENSIONS
  	    fprintf(fp, "class\t\t%s\n", up->u_class) <= 0 ||
  #endif
  	    fprintf(fp, "inactive\t%s\n", (up->u_inactive == NULL) ? UNSET_INACTIVE : up->u_inactive) <= 0 ||
  	    fprintf(fp, "expire\t\t%s\n", (up->u_expire == NULL) ? UNSET_EXPIRY : up->u_expire) <= 0 ||
  	    fprintf(fp, "preserve\t%s\n", (up->u_preserve == 0) ? "false" : "true") <= 0) {
  		warn("can't write to `%s'", CONFFILE);
  		ret = 0;
  	}
  #ifdef EXTENSIONS
  	for (i = (up->u_defrc != up->u_rc) ? up->u_defrc : 0 ; i < up->u_rc ; i++) {
  		if (fprintf(fp, "range\t\t%d..%d\n", up->u_rv[i].r_from, up->u_rv[i].r_to) <= 0) {
  			warn("can't write to `%s'", CONFFILE);
  			ret = 0;
  		}
  	}
  #endif
  	if (fclose(fp) == EOF) {
  		warn("can't write to `%s'", CONFFILE);
  		ret = 0;
  	}
  	if (ret) {
  		ret = ((rename(template, CONFFILE) == 0) && (chmod(CONFFILE, 0644) == 0));
  	}
  	return ret;
  }
  
  /* read the defaults file */
  static void
  read_defaults(user_t *up)
  {
  	struct stat	st;
  	size_t		lineno;
  	size_t		len;
  	FILE		*fp;
  	unsigned char	*cp;
  	unsigned char	*s;
  
  	memsave(&up->u_primgrp, DEF_GROUP, strlen(DEF_GROUP));
  	memsave(&up->u_basedir, DEF_BASEDIR, strlen(DEF_BASEDIR));
  	memsave(&up->u_skeldir, DEF_SKELDIR, strlen(DEF_SKELDIR));
  	memsave(&up->u_shell, DEF_SHELL, strlen(DEF_SHELL));
  	memsave(&up->u_comment, DEF_COMMENT, strlen(DEF_COMMENT));
  #ifdef EXTENSIONS
  	memsave(&up->u_class, DEF_CLASS, strlen(DEF_CLASS));
  #endif
  	up->u_rsize = 16;
  	up->u_defrc = 0;
  	NEWARRAY(range_t, up->u_rv, up->u_rsize, exit(1));
  	up->u_inactive = DEF_INACTIVE;
  	up->u_expire = DEF_EXPIRE;
  	if ((fp = fopen(CONFFILE, "r")) == NULL) {
  		if (stat(CONFFILE, &st) < 0 && !setdefaults(up)) {
  			warn("can't create `%s' defaults file", CONFFILE);
  		}
  		fp = fopen(CONFFILE, "r");
  	}
  	if (fp != NULL) {
  		while ((s = fparseln(fp, &len, &lineno, NULL, 0)) != NULL) {
  			if (strncmp(s, "group", 5) == 0) {
  				for (cp = s + 5 ; isspace(*cp) ; cp++) {
  				}
  				memsave(&up->u_primgrp, cp, strlen(cp));
  			} else if (strncmp(s, "base_dir", 8) == 0) {
  				for (cp = s + 8 ; isspace(*cp) ; cp++) {
  				}
  				memsave(&up->u_basedir, cp, strlen(cp));
  			} else if (strncmp(s, "skel_dir", 8) == 0) {
  				for (cp = s + 8 ; isspace(*cp) ; cp++) {
  				}
  				memsave(&up->u_skeldir, cp, strlen(cp));
  			} else if (strncmp(s, "shell", 5) == 0) {
  				for (cp = s + 5 ; isspace(*cp) ; cp++) {
  				}
  				memsave(&up->u_shell, cp, strlen(cp));
  			} else if (strncmp(s, "password", 8) == 0) {
  				for (cp = s + 8 ; isspace(*cp) ; cp++) {
  				}
  				memsave(&up->u_password, cp, strlen(cp));
  #ifdef EXTENSIONS
  			} else if (strncmp(s, "class", 5) == 0) {
  				for (cp = s + 5 ; isspace(*cp) ; cp++) {
  				}
  				memsave(&up->u_class, cp, strlen(cp));
  #endif
  			} else if (strncmp(s, "inactive", 8) == 0) {
  				for (cp = s + 8 ; isspace(*cp) ; cp++) {
  				}
  				if (strcmp(cp, UNSET_INACTIVE) == 0) {
  					if (up->u_inactive) {
  						FREE(up->u_inactive);
  					}
  					up->u_inactive = NULL;
  				} else {
  					memsave(&up->u_inactive, cp, strlen(cp));
  				}
  #ifdef EXTENSIONS
  			} else if (strncmp(s, "range", 5) == 0) {
  				for (cp = s + 5 ; isspace(*cp) ; cp++) {
  				}
  				(void) save_range(up, cp);
  #endif
  #ifdef EXTENSIONS
  			} else if (strncmp(s, "preserve", 8) == 0) {
  				for (cp = s + 8 ; isspace(*cp) ; cp++) {
  				}
  				up->u_preserve = (strncmp(cp, "true", 4) == 0) ? 1 :
  						  (strncmp(cp, "yes", 3) == 0) ? 1 :
  						   atoi(cp);
  #endif
  			} else if (strncmp(s, "expire", 6) == 0) {
  				for (cp = s + 6 ; isspace(*cp) ; cp++) {
  				}
  				if (strcmp(cp, UNSET_EXPIRY) == 0) {
  					if (up->u_expire) {
  						FREE(up->u_expire);
  					}
  					up->u_expire = NULL;
  				} else {
  					memsave(&up->u_expire, cp, strlen(cp));
  				}
  			}
  			(void) free(s);
  		}
  		(void) fclose(fp);
  	}
  	if (up->u_rc == 0) {
  		up->u_rv[up->u_rc].r_from = DEF_LOWUID;
  		up->u_rv[up->u_rc].r_to = DEF_HIGHUID;
  		up->u_rc += 1;
  	}
  	up->u_defrc = up->u_rc;
  }
  
  /* return the next valid unused uid */
  static int
  getnextuid(int sync_uid_gid, uid_t *uid, uid_t low_uid, uid_t high_uid)
  {
  	for (*uid = low_uid ; *uid <= high_uid ; (*uid)++) {
  		if (getpwuid((uid_t)(*uid)) == NULL && *uid != NOBODY_UID) {
  			if (sync_uid_gid) {
  				if (getgrgid((gid_t)(*uid)) == NULL) {
  					return 1;
  				}
  			} else {
  				return 1;
  			}
  		}
  	}
  	return 0;
  }
  
  /* structure which defines a password type */
  typedef struct passwd_type_t {
  	const char     *type;		/* optional type descriptor */
  	int		desc_length;	/* length of type descriptor */
  	int		length;		/* length of password */
  } passwd_type_t;
  
  #define BLF "$2a"
  #define MD5 "$1"
  #define DES ""
  
  static passwd_type_t	passwd_types[] = {
  	{ BLF,	3,	54	},	/* Blowfish */
  	{ MD5,	2,	34	},	/* MD5 */
  	{ DES,	0,	DES_Len	},	/* standard DES */
  	{ NULL,	-1,	-1	}	/* none - terminate search */
  };
  
  /* return non-zero if it's a valid password - check length for cipher type */
  static int
  valid_password_length(char *newpasswd)
  {
  	passwd_type_t  *pwtp;
  
  	for (pwtp = passwd_types ; pwtp->desc_length >= 0 ; pwtp++) {
  		if (strncmp(newpasswd, pwtp->type, pwtp->desc_length) == 0) {
  			char *p;
  
  			if (strcmp(pwtp->type, BLF) != 0) {
  				return strlen(newpasswd) == pwtp->length;
  			}
  			/* Skip first three `$'. */
  			if ((p = strchr(newpasswd, '$')) == NULL ||
  			    *(++p) == '$' || (p = strchr(p, '$')) == NULL ||
  			    *(++p) == '$' || (p = strchr(p, '$')) == NULL)
  				continue;
  			return (strlen(p) - 1);
  		}
  	}
  	return 0;
  }
  
  /* look for a valid time, return 0 if it was specified but bad */
  static int
  scantime(time_t *tp, char *s)
  {
  	struct tm	tm;
  
  	*tp = 0;
  	if (s != NULL) {
  		(void) memset(&tm, 0, sizeof(tm));
  		tm.tm_isdst = -1;
  		if (strptime(s, "%c", &tm) != NULL) {
  			*tp = mktime(&tm);
  		} else if (strptime(s, "%B %d %Y", &tm) != NULL) {
  			*tp = mktime(&tm);
  		} else if (isdigit((unsigned char) s[0]) != 0) {
  			*tp = atoi(s);
  		} else {
  			return 0;
  		}
  	}
  	return 1;
  }
  
  /* compute the extra length '&' expansion consumes */
  static size_t
  expand_len(const char *p, const char *username)
  {
  	size_t alen;
  	size_t ulen;
  
  	ulen = strlen(username);
  	for (alen = 0; *p != '\0'; p++)
  		if (*p == '&')
  			alen += ulen - 1;
  	return alen;
  }
  
  /* add a user */
  static int
  adduser(char *login_name, user_t *up)
  {
  	struct group	*grp;
  	struct stat	st;
  	time_t		expire;
  	time_t		inactive;
  	char		password[PasswordLength + 1];
  	char		home[MaxFileNameLen];
  	char		buf[LINE_MAX];
  	int		sync_uid_gid;
  	int		masterfd;
  	int		ptmpfd;
  	gid_t		gid;
  	int		cc;
  	int		i, yp = 0;
  	FILE		*fp;
  
  	if (!valid_login(login_name)) {
  		errx(EXIT_FAILURE, "`%s' is not a valid login name", login_name);
  	}
  #ifdef EXTENSIONS
  	if (!valid_class(up->u_class)) {
  		errx(EXIT_FAILURE, "No such login class `%s'", up->u_class);
  	}
  #endif
  	if ((masterfd = open(_PATH_MASTERPASSWD, O_RDONLY)) < 0) {
  		err(EXIT_FAILURE, "can't open `%s'", _PATH_MASTERPASSWD);
  	}
  	if (flock(masterfd, LOCK_EX | LOCK_NB) < 0) {
  		err(EXIT_FAILURE, "can't lock `%s'", _PATH_MASTERPASSWD);
  	}
  	pw_init();
  	if ((ptmpfd = pw_lock(WAITSECS)) < 0) {
  		(void) close(masterfd);
  		err(EXIT_FAILURE, "can't obtain pw_lock");
  	}
  	if ((fp = fdopen(masterfd, "r")) == NULL) {
  		(void) close(masterfd);
  		(void) close(ptmpfd);
  		pw_abort();
  		err(EXIT_FAILURE, "can't fdopen `%s' for reading",
  		    _PATH_MASTERPASSWD);
  	}
  	while (fgets(buf, sizeof(buf), fp) != NULL) {
  		cc = strlen(buf);
  		/*
  		 * Stop copying the file at the yp entry; we want to
  		 * put the new user before it, and preserve entries
  		 * after the yp entry.
  		 */
  		if (cc > 1 && buf[0] == '+' && buf[1] == ':') {
  			yp = 1;
  			break;
  		}
  		if (write(ptmpfd, buf, (size_t)(cc)) != cc) {
  			(void) fclose(fp);
  			(void) close(ptmpfd);
  			pw_abort();
  			err(EXIT_FAILURE, "short write to /etc/ptmp (not %d chars)", cc);
  		}
  	}
  	if (ferror(fp)) {
  		(void) fclose(fp);
  		(void) close(ptmpfd);
  		pw_abort();
  		err(EXIT_FAILURE, "read error on %s", _PATH_MASTERPASSWD);
  	}
  	/* if no uid was specified, get next one in [low_uid..high_uid] range */
  	sync_uid_gid = (strcmp(up->u_primgrp, "=uid") == 0);
  	if (up->u_uid == UID_MAX) {
  		int got_id = 0;
  
  		/*
  		 * Look for a free UID in the command line ranges (if any).
  		 * These start after the ranges specified in the config file.
  		 */
  		for (i = up->u_defrc; got_id == 0 && i < up->u_rc ; i++) {
  			got_id = getnextuid(sync_uid_gid, &up->u_uid,
  			    up->u_rv[i].r_from, up->u_rv[i].r_to);
  	 	}
  		/*
  		 * If there were no free UIDs in the command line ranges,
  		 * try the ranges from the config file (there will always
  		 * be at least one default).
  		 */
  		if (got_id == 0) {
  			for (i = 0; got_id == 0 && i < up->u_defrc; i++) {
  				got_id = getnextuid(sync_uid_gid, &up->u_uid,
  				    up->u_rv[i].r_from, up->u_rv[i].r_to);
  			}
  		}
  		if (got_id == 0) {
  			(void) close(ptmpfd);
  			pw_abort();
  			errx(EXIT_FAILURE, "can't get next uid for %u", up->u_uid);
  		}
  	}
  	/* check uid isn't already allocated */
  	if (!(up->u_flags & F_DUPUID) && getpwuid((uid_t)(up->u_uid)) != NULL) {
  		(void) close(ptmpfd);
  		pw_abort();
  		errx(EXIT_FAILURE, "uid %u is already in use", up->u_uid);
  	}
  	/* if -g=uid was specified, check gid is unused */
  	if (sync_uid_gid) {
  		if (getgrgid((gid_t)(up->u_uid)) != NULL) {
  			(void) close(ptmpfd);
  			pw_abort();
  			errx(EXIT_FAILURE, "gid %u is already in use", up->u_uid);
  		}
  		gid = up->u_uid;
  	} else if ((grp = getgrnam(up->u_primgrp)) != NULL) {
  		gid = grp->gr_gid;
  	} else if (is_number(up->u_primgrp) &&
  		   (grp = getgrgid((gid_t)atoi(up->u_primgrp))) != NULL) {
  		gid = grp->gr_gid;
  	} else {
  		(void) close(ptmpfd);
  		pw_abort();
  		errx(EXIT_FAILURE, "group %s not found", up->u_primgrp);
  	}
  	/* check name isn't already in use */
  	if (!(up->u_flags & F_DUPUID) && getpwnam(login_name) != NULL) {
  		(void) close(ptmpfd);
  		pw_abort();
  		errx(EXIT_FAILURE, "already a `%s' user", login_name);
  	}
  	if (up->u_flags & F_HOMEDIR) {
  		if (strlcpy(home, up->u_home, sizeof(home)) >= sizeof(home)) {
  			(void) close(ptmpfd);
  			pw_abort();
  			errx(EXIT_FAILURE, "home directory `%s' too long",
  			    up->u_home);
  		}
  	} else {
  		/* if home directory hasn't been given, make it up */
  		if (snprintf(home, sizeof(home), "%s/%s", up->u_basedir,
  		    login_name) >= sizeof(home)) {
  			(void) close(ptmpfd);
  			pw_abort();
  			errx(EXIT_FAILURE, "home directory `%s/%s' too long",
  			    up->u_basedir, login_name);
  		}
  	}
  	if (!scantime(&inactive, up->u_inactive)) {
  		warnx("Warning: inactive time `%s' invalid, password expiry off",
  				up->u_inactive);
  	}
  	if (!scantime(&expire, up->u_expire)) {
  		warnx("Warning: expire time `%s' invalid, account expiry off",
  				up->u_expire);
  	}
  	if (lstat(home, &st) < 0 && !(up->u_flags & F_MKDIR) &&
  	    strcmp(home, _PATH_NONEXISTENT) != 0) {
  		warnx("Warning: home directory `%s' doesn't exist, and -m was"
  		    " not specified", home);
  	}
  	if (up->u_password != NULL && valid_password_length(up->u_password)) {
  		(void) strlcpy(password, up->u_password, sizeof(password));
  	} else {
  		(void) memset(password, '*', DES_Len);
  		password[DES_Len] = 0;
  		if (up->u_password != NULL) {
  			warnx("Password `%s' is invalid: setting it to `%s'",
  				up->u_password, password);
  		}
  	}
  	cc = snprintf(buf, sizeof(buf), "%s:%s:%d:%d:%s:%ld:%ld:%s:%s:%s\n",
  	    login_name,
  	    password,
  	    up->u_uid,
  	    gid,
  #ifdef EXTENSIONS
  	    up->u_class,
  #else
  	    "",
  #endif
  	    (long) inactive,
  	    (long) expire,
  	    up->u_comment,
  	    home,
  	    up->u_shell);
  	if (cc >= sizeof(buf) || cc < 0 ||
  	    cc + expand_len(up->u_comment, login_name) >= 1023) {
  		(void) close(ptmpfd);
  		pw_abort();
  		errx(EXIT_FAILURE, "can't add `%s', line too long", buf);
  	}
  	if (write(ptmpfd, buf, (size_t) cc) != cc) {
  		(void) close(ptmpfd);
  		pw_abort();
  		err(EXIT_FAILURE, "can't add `%s'", buf);
  	}
  	if (yp) {
  		/* put back the + line */
  		cc = snprintf(buf, sizeof(buf), "+:*::::::::\n");
  		if (cc == -1 || cc >= sizeof(buf)) {
  			(void) close(ptmpfd);
  			pw_abort();
  			errx(EXIT_FAILURE, "can't add `%s', line too long", buf);
  		}
  		if (write(ptmpfd, buf, (size_t) cc) != cc) {
  			(void) close(ptmpfd);
  			pw_abort();
  			err(EXIT_FAILURE, "can't add `%s'", buf);
  		}
  		/* copy the entries following it, if any */
  		while (fgets(buf, sizeof(buf), fp) != NULL) {
  			cc = strlen(buf);
  			if (write(ptmpfd, buf, (size_t)(cc)) != cc) {
  				(void) fclose(fp);
  				(void) close(ptmpfd);
  				pw_abort();
  				err(EXIT_FAILURE, "short write to /etc/ptmp (not %d chars)", cc);
  			}
  		}
  		if (ferror(fp)) {
  			(void) fclose(fp);
  			(void) close(ptmpfd);
  			pw_abort();
  			err(EXIT_FAILURE, "read error on %s", _PATH_MASTERPASSWD);
  		}
  	}
  	if (up->u_flags & F_MKDIR) {
  		if (lstat(home, &st) == 0) {
  			(void) close(ptmpfd);
  			pw_abort();
  			errx(EXIT_FAILURE, "home directory `%s' already exists",
  			    home);
  		} else {
  			if (asystem("%s -p %s", MKDIR, home) != 0) {
  				(void) close(ptmpfd);
  				pw_abort();
  				err(EXIT_FAILURE, "can't mkdir `%s'", home);
  			}
  			(void) copydotfiles(up->u_skeldir, up->u_uid, gid, home);
  		}
  	}
  	if (strcmp(up->u_primgrp, "=uid") == 0 &&
  	    getgrnam(login_name) == NULL &&
  	    !creategid(login_name, gid, login_name)) {
  		(void) close(ptmpfd);
  		pw_abort();
  		errx(EXIT_FAILURE, "can't create gid %d for login name %s",
  		    gid, login_name);
  	}
  	if (up->u_groupc > 0 && !append_group(login_name, up->u_groupc, up->u_groupv)) {
  		(void) close(ptmpfd);
  		pw_abort();
  		errx(EXIT_FAILURE, "can't append `%s' to new groups", login_name);
  	}
  	(void) close(ptmpfd);
  	if (pw_mkdb(yp ? NULL : login_name, 0) < 0) {
  		pw_abort();
  		err(EXIT_FAILURE, "pw_mkdb failed");
  	}
  	syslog(LOG_INFO, "new user added: name=%s, uid=%d, gid=%d, home=%s, shell=%s",
  		login_name, up->u_uid, gid, home, up->u_shell);
  	return 1;
  }
  
  /* remove a user from the groups file */
  static int
  rm_user_from_groups(char *login_name)
  {
  	struct stat	st;
  	size_t		login_len;
  	FILE		*from;
  	FILE		*to;
  	char		buf[LINE_MAX];
  	char		f[MaxFileNameLen];
  	char		*cp, *ep;
  	int		fd;
  	int		cc;
  
  	login_len = strlen(login_name);
  	if ((from = fopen(_PATH_GROUP, "r")) == NULL) {
  		warn("can't remove gid for `%s': can't open `%s'",
  		    login_name, _PATH_GROUP);
  		return 0;
  	}
  	if (flock(fileno(from), LOCK_EX | LOCK_NB) < 0) {
  		warn("can't lock `%s'", _PATH_GROUP);
  	}
  	(void) fstat(fileno(from), &st);
  	(void) snprintf(f, sizeof(f), "%s.XXXXXXXX", _PATH_GROUP);
  	if ((fd = mkstemp(f)) < 0) {
  		(void) fclose(from);
  		warn("can't remove gid for `%s': mkstemp failed", login_name);
  		return 0;
  	}
  	if ((to = fdopen(fd, "w")) == NULL) {
  		(void) fclose(from);
  		(void) close(fd);
  		(void) unlink(f);
  		warn("can't remove gid for `%s': fdopen `%s' failed",
  		    login_name, f);
  		return 0;
  	}
  	while (fgets(buf, sizeof(buf), from) > 0) {
  		cc = strlen(buf);
  		if (cc > 0 && buf[cc - 1] != '\n' && !feof(from)) {
  			while (fgetc(from) != '\n' && !feof(from))
  				cc++;
  			warnx("%s: line `%s' too long (%d bytes), skipping",
  			    _PATH_GROUP, buf, cc);
  			continue;
  		}
  
  		/* Break out the group list. */
  		for (cp = buf, cc = 0; *cp != '\0' && cc < 3; cp++) {
  			if (*cp == ':')
  				cc++;
  		}
  		if (cc != 3) {
  			buf[strcspn(buf, "\n")] = '\0';
  			warnx("Malformed entry `%s'. Skipping", buf);
  			continue;
  		}
  		while ((cp = strstr(cp, login_name)) != NULL) {
  			if ((cp[-1] == ':' || cp[-1] == ',') &&
  			    (cp[login_len] == ',' || cp[login_len] == '\n')) {
  				ep = cp + login_len;
  				if (cp[login_len] == ',')
  					ep++;
  				else if (cp[-1] == ',')
  					cp--;
  				memmove(cp, ep, strlen(ep) + 1);
  			} else {
  				if ((cp = strchr(cp, ',')) == NULL)
  					break;
  				cp++;
  			}
  		}
  		if (fwrite(buf, strlen(buf), 1, to) != 1) {
  			(void) fclose(from);
  			(void) fclose(to);
  			(void) unlink(f);
  			warn("can't remove gid for `%s': short write to `%s'",
  			    login_name, f);
  			return 0;
  		}
  	}
  	(void) fchmod(fileno(to), st.st_mode & 07777);
  	(void) fclose(from);
  	if (fclose(to) == EOF) {
  		(void) unlink(f);
  		warn("can't remove gid for `%s': short write to `%s'",
  		    login_name, f);
  		return 0;
  	}
  	if (rename(f, _PATH_GROUP) < 0) {
  		(void) unlink(f);
  		warn("can't remove gid for `%s': can't rename `%s' to `%s'",
  		    login_name, f, _PATH_GROUP);
  		return 0;
  	}
  	return 1;
  }
  
  /* check that the user or group is local, not from YP/NIS */
  static int
  is_local(char *name, const char *file)
  {
  	FILE	       *fp;
  	char		buf[LINE_MAX];
  	size_t		len;
  	int		ret;
  	int		cc;
  
  	if ((fp = fopen(file, "r")) == NULL) {
  		err(EXIT_FAILURE, "can't open `%s'", file);
  	}
  	len = strlen(name);
  	for (ret = 0 ; fgets(buf, sizeof(buf), fp) != NULL ; ) {
  		cc = strlen(buf);
  		if (cc > 0 && buf[cc - 1] != '\n' && !feof(fp)) {
  			while (fgetc(fp) != '\n' && !feof(fp))
  				cc++;
  			warnx("%s: line `%s' too long (%d bytes), skipping",
  			    file, buf, cc);
  			continue;
  		}
  		if (strncmp(buf, name, len) == 0 && buf[len] == ':') {
  			ret = 1;
  			break;
  		}
  	}
  	(void) fclose(fp);
  	return ret;
  }
  
  /* modify a user */
  static int
  moduser(char *login_name, char *newlogin, user_t *up)
  {
  	struct passwd	*pwp;
  	struct group	*grp;
  	const char	*homedir;
  	char		buf[LINE_MAX];
  	size_t		colonc, loginc;
  	size_t		cc;
  	FILE		*master;
  	char		newdir[MaxFileNameLen];
  	char		*colon;
  	int		len;
  	int		masterfd;
  	int		ptmpfd;
  	int		rval;
  
  	if (!valid_login(newlogin)) {
  		errx(EXIT_FAILURE, "`%s' is not a valid login name", login_name);
  	}
  	if ((pwp = getpwnam(login_name)) == NULL) {
  		errx(EXIT_FAILURE, "No such user `%s'", login_name);
  	}
  	if (!is_local(login_name, _PATH_MASTERPASSWD)) {
  		errx(EXIT_FAILURE, "User `%s' must be a local user", login_name);
  	}
  	/* keep dir name in case we need it for '-m' */
  	homedir = pwp->pw_dir;
  
  	if ((masterfd = open(_PATH_MASTERPASSWD, O_RDONLY)) < 0) {
  		err(EXIT_FAILURE, "can't open `%s'", _PATH_MASTERPASSWD);
  	}
  	if (flock(masterfd, LOCK_EX | LOCK_NB) < 0) {
  		err(EXIT_FAILURE, "can't lock `%s'", _PATH_MASTERPASSWD);
  	}
  	pw_init();
  	if ((ptmpfd = pw_lock(WAITSECS)) < 0) {
  		(void) close(masterfd);
  		err(EXIT_FAILURE, "can't obtain pw_lock");
  	}
  	if ((master = fdopen(masterfd, "r")) == NULL) {
  		(void) close(masterfd);
  		(void) close(ptmpfd);
  		pw_abort();
  		err(EXIT_FAILURE, "can't fdopen fd for %s", _PATH_MASTERPASSWD);
  	}
  	if (up != NULL) {
  		if (up->u_flags & F_USERNAME) {
  			/* if changing name, check new name isn't already in use */
  			if (strcmp(login_name, newlogin) != 0 && getpwnam(newlogin) != NULL) {
  				(void) close(ptmpfd);
  				pw_abort();
  				errx(EXIT_FAILURE, "already a `%s' user", newlogin);
  			}
  			pwp->pw_name = newlogin;
  
  			/*
  			 * Provide a new directory name in case the
  			 * home directory is to be moved.
  			 */
  			if (up->u_flags & F_MKDIR) {
  				(void) snprintf(newdir, sizeof(newdir),
  				    "%s/%s", up->u_basedir, newlogin);
  				pwp->pw_dir = newdir;
  			}
  		}
  		if (up->u_flags & F_PASSWORD) {
  			if (up->u_password != NULL) {
  				if (!valid_password_length(up->u_password)) {
  					(void) close(ptmpfd);
  					pw_abort();
  					errx(EXIT_FAILURE, "Invalid password: `%s'",
  						up->u_password);
  				}
  				pwp->pw_passwd = up->u_password;
  			}
  		}
  		if (up->u_flags & F_UID) {
  			/* check uid isn't already allocated */
  			if (!(up->u_flags & F_DUPUID) && getpwuid((uid_t)(up->u_uid)) != NULL) {
  				(void) close(ptmpfd);
  				pw_abort();
  				errx(EXIT_FAILURE, "uid %u is already in use", up->u_uid);
  			}
  			pwp->pw_uid = up->u_uid;
  		}
  		if (up->u_flags & F_GROUP) {
  			/* if -g=uid was specified, check gid is unused */
  			if (strcmp(up->u_primgrp, "=uid") == 0) {
  				if (getgrgid((gid_t)(up->u_uid)) != NULL) {
  					(void) close(ptmpfd);
  					pw_abort();
  					errx(EXIT_FAILURE, "gid %u is already in use", up->u_uid);
  				}
  				pwp->pw_gid = up->u_uid;
  			} else if ((grp = getgrnam(up->u_primgrp)) != NULL) {
  				pwp->pw_gid = grp->gr_gid;
  			} else if (is_number(up->u_primgrp) &&
  				   (grp = getgrgid((gid_t)atoi(up->u_primgrp))) != NULL) {
  				pwp->pw_gid = grp->gr_gid;
  			} else {
  				(void) close(ptmpfd);
  				pw_abort();
  				errx(EXIT_FAILURE, "group %s not found", up->u_primgrp);
  			}
  		}
  		if (up->u_flags & F_INACTIVE) {
  			if (!scantime(&pwp->pw_change, up->u_inactive)) {
  				warnx("Warning: inactive time `%s' invalid, password expiry off",
  					up->u_inactive);
  			}
  		}
  		if (up->u_flags & F_EXPIRE) {
  			if (!scantime(&pwp->pw_expire, up->u_expire)) {
  				warnx("Warning: expire time `%s' invalid, account expiry off",
  					up->u_expire);
  			}
  		}
  		if (up->u_flags & F_COMMENT)
  			pwp->pw_gecos = up->u_comment;
  		if (up->u_flags & F_HOMEDIR)
  			pwp->pw_dir = up->u_home;
  		if (up->u_flags & F_SHELL)
  			pwp->pw_shell = up->u_shell;
  #ifdef EXTENSIONS
  		if (up->u_flags & F_CLASS) {
  			if (!valid_class(up->u_class)) {
  				(void) close(ptmpfd);
  				pw_abort();
  				errx(EXIT_FAILURE,
  				    "No such login class `%s'", up->u_class);
  			}
  			pwp->pw_class = up->u_class;
  		}
  #endif
  	}
  	loginc = strlen(login_name);
  	while (fgets(buf, sizeof(buf), master) != NULL) {
  		if ((colon = strchr(buf, ':')) == NULL) {
  			warnx("Malformed entry `%s'. Skipping", buf);
  			continue;
  		}
  		colonc = (size_t)(colon - buf);
  		if (strncmp(login_name, buf, loginc) == 0 && loginc == colonc) {
  			if (up != NULL) {
  				if ((len = snprintf(buf, sizeof(buf),
  				    "%s:%s:%d:%d:%s:%ld:%ld:%s:%s:%s\n",
  				    newlogin,
  				    pwp->pw_passwd,
  				    pwp->pw_uid,
  				    pwp->pw_gid,
  #ifdef EXTENSIONS
  				    pwp->pw_class,
  #else
  				    "",
  #endif
  				    (long)pwp->pw_change,
  				    (long)pwp->pw_expire,
  				    pwp->pw_gecos,
  				    pwp->pw_dir,
  				    pwp->pw_shell)) >= sizeof(buf) || len < 0 ||
  				    len + expand_len(pwp->pw_gecos, newlogin)
  				    >= 1023) {
  					(void) close(ptmpfd);
  					pw_abort();
  					errx(EXIT_FAILURE, "can't add `%s', "
  					    "line too long (%d bytes)", buf,
  					    len + expand_len(pwp->pw_gecos,
  					    newlogin));
  				}
  				if (write(ptmpfd, buf, len) != len) {
  					(void) close(ptmpfd);
  					pw_abort();
  					err(EXIT_FAILURE, "can't add `%s'", buf);
  				}
  			}
  		} else {
  			len = strlen(buf);
  			if ((cc = write(ptmpfd, buf, len)) != len) {
  				(void) close(masterfd);
  				(void) close(ptmpfd);
  				pw_abort();
  				err(EXIT_FAILURE, "short write to /etc/ptmp (%lld not %lld chars)",
  				    (long long)cc, (long long)len);
  			}
  		}
  	}
  	if (up != NULL) {
  		if ((up->u_flags & F_MKDIR) &&
  		    asystem("%s %s %s", MV, homedir, pwp->pw_dir) != 0) {
  			(void) close(ptmpfd);
  			pw_abort();
  			err(EXIT_FAILURE, "can't move `%s' to `%s'",
  			    homedir, pwp->pw_dir);
  		}
  		if (up->u_groupc > 0 &&
  		    !append_group(newlogin, up->u_groupc, up->u_groupv)) {
  			(void) close(ptmpfd);
  			pw_abort();
  			errx(EXIT_FAILURE, "can't append `%s' to new groups",
  			    newlogin);
  		}
  	}
  	(void) close(ptmpfd);
  	if (up != NULL && strcmp(login_name, newlogin) == 0)
  		rval = pw_mkdb(login_name, 0);
  	else
  		rval = pw_mkdb(NULL, 0);
  	if (rval == -1) {
  		pw_abort();
  		err(EXIT_FAILURE, "pw_mkdb failed");
  	}
  	if (up == NULL) {
  		syslog(LOG_INFO, "user removed: name=%s", login_name);
  	} else if (strcmp(login_name, newlogin) == 0) {
  		syslog(LOG_INFO, "user information modified: name=%s, uid=%d, gid=%d, home=%s, shell=%s",
  			login_name, pwp->pw_uid, pwp->pw_gid, pwp->pw_dir, pwp->pw_shell);
  	} else {
  		syslog(LOG_INFO, "user information modified: name=%s, new name=%s, uid=%d, gid=%d, home=%s, shell=%s",
  			login_name, newlogin, pwp->pw_uid, pwp->pw_gid, pwp->pw_dir, pwp->pw_shell);
  	}
  	return 1;
  }
  
  
  #ifdef EXTENSIONS
  /* see if we can find out the user struct */
  static struct passwd *
  find_user_info(char *name)
  {
  	struct passwd	*pwp;
  
  	if ((pwp = getpwnam(name)) != NULL) {
  		return pwp;
  	}
  	if (is_number(name) && (pwp = getpwuid((uid_t)atoi(name))) != NULL) {
  		return pwp;
  	}
  	return NULL;
  }
  #endif
  
  #ifdef EXTENSIONS
  /* see if we can find out the group struct */
  static struct group *
  find_group_info(char *name)
  {
  	struct group	*grp;
  
  	if ((grp = getgrnam(name)) != NULL) {
  		return grp;
  	}
  	if (is_number(name) && (grp = getgrgid((gid_t)atoi(name))) != NULL) {
  		return grp;
  	}
  	return NULL;
  }
  #endif
  
  /* print out usage message, and then exit */
  void
  usermgmt_usage(const char *prog)
  {
  	if (strcmp(prog, "useradd") == 0) {
  		(void) fprintf(stderr, "usage: %s -D [-b base-directory] "
  		    "[-e expiry-time] [-f inactive-time]\n"
  		    "               [-g gid | name | =uid] [-k skel-directory] "
  		    "[-L login-class]\n"
  		    "               [-r low..high] [-s shell]\n", prog);
  		(void) fprintf(stderr, "       %s [-mov] [-b base-directory] "
  		    "[-c comment] [-d home-directory]\n"
  		    "               [-e expiry-time] [-f inactive-time]\n"
  		    "               [-G secondary-group[,group,...]] "
  		    "[-g gid | name | =uid]\n"
  		    "               [-k skel-directory] [-L login-class] "
  		    "[-p password] [-r low..high]\n"
  		    "               [-s shell] [-u uid] user\n", prog);
  	} else if (strcmp(prog, "usermod") == 0) {
  		(void) fprintf(stderr, "usage: %s [-mov] "
  		    "[-c comment] [-d home-directory] [-e expiry-time]\n"
  		    "               [-f inactive-time] "
  		    "[-G secondary-group[,group,...]]\n"
  		    "               [-g gid | name | =uid] [-L login-class] "
  		    "[-l new-login]\n"
  		    "               [-p password] [-s shell] [-u uid] user\n",
  		    prog);
  	} else if (strcmp(prog, "userdel") == 0) {
  		(void) fprintf(stderr, "usage: %s -D [-p preserve-value]\n",
  		    prog);
  		(void) fprintf(stderr, "       %s [-prv] user\n", prog);
  #ifdef EXTENSIONS
  	} else if (strcmp(prog, "userinfo") == 0) {
  		(void) fprintf(stderr, "usage: %s [-e] user\n", prog);
  #endif
  	} else if (strcmp(prog, "groupadd") == 0) {
  		(void) fprintf(stderr, "usage: %s [-ov] [-g gid] group\n",
  		    prog);
  	} else if (strcmp(prog, "groupdel") == 0) {
  		(void) fprintf(stderr, "usage: %s [-v] group\n", prog);
  	} else if (strcmp(prog, "groupmod") == 0) {
  		(void) fprintf(stderr, "usage: %s [-ov] [-g gid] [-n newname] "
  		    "group\n", prog);
  	} else if (strcmp(prog, "user") == 0 || strcmp(prog, "group") == 0) {
  		(void) fprintf(stderr, "usage: %s [add | del | mod"
  #ifdef EXTENSIONS
  		" | info"
  #endif
  		"] ...\n",
  		    prog);
  #ifdef EXTENSIONS
  	} else if (strcmp(prog, "groupinfo") == 0) {
  		(void) fprintf(stderr, "usage: %s [-e] group\n", prog);
  #endif
  	} else {
  		(void) fprintf(stderr, "This program must be called as {user,group}{add,del,mod,info},\n%s is not an understood name.\n", prog);
  	}
  	exit(EXIT_FAILURE);
  	/* NOTREACHED */
  }
  
  #ifdef EXTENSIONS
  #define ADD_OPT_EXTENSIONS	"p:r:vL:"
  #else
  #define ADD_OPT_EXTENSIONS	
  #endif
  
  int
  useradd(int argc, char **argv)
  {
  	user_t	u;
  	int	defaultfield;
  	int	bigD;
  	int	c;
  #ifdef EXTENSIONS
  	int	i;
  #endif
  
  	(void) memset(&u, 0, sizeof(u));
  	read_defaults(&u);
  	u.u_uid = UID_MAX;
  	defaultfield = bigD = 0;
  	while ((c = getopt(argc, argv, "DG:b:c:d:e:f:g:k:mou:s:" ADD_OPT_EXTENSIONS)) != -1) {
  		switch(c) {
  		case 'D':
  			bigD = 1;
  			break;
  		case 'G':
  			while ((u.u_groupv[u.u_groupc] = strsep(&optarg, ",")) != NULL &&
  			    u.u_groupc < NGROUPS_MAX - 2) {
  				if (u.u_groupv[u.u_groupc][0] != 0) {
  					u.u_groupc++;
  				}
  			}
  			if (optarg != NULL) {
  				warnx("Truncated list of secondary groups to %d entries", NGROUPS_MAX - 2);
  			}
  			break;
  		case 'b':
  			defaultfield = 1;
  			memsave(&u.u_basedir, optarg, strlen(optarg));
  			break;
  		case 'c':
  			memsave(&u.u_comment, optarg, strlen(optarg));
  			break;
  		case 'd':
  			memsave(&u.u_home, optarg, strlen(optarg));
  			u.u_flags |= F_HOMEDIR;
  			break;
  		case 'e':
  			defaultfield = 1;
  			memsave(&u.u_expire, optarg, strlen(optarg));
  			break;
  		case 'f':
  			defaultfield = 1;
  			memsave(&u.u_inactive, optarg, strlen(optarg));
  			break;
  		case 'g':
  			defaultfield = 1;
  			memsave(&u.u_primgrp, optarg, strlen(optarg));
  			break;
  		case 'k':
  			defaultfield = 1;
  			memsave(&u.u_skeldir, optarg, strlen(optarg));
  			break;
  #ifdef EXTENSIONS
  		case 'L':
  			defaultfield = 1;
  			memsave(&u.u_class, optarg, strlen(optarg));
  			break;
  #endif
  		case 'm':
  			u.u_flags |= F_MKDIR;
  			break;
  		case 'o':
  			u.u_flags |= F_DUPUID;
  			break;
  #ifdef EXTENSIONS
  		case 'p':
  			memsave(&u.u_password, optarg, strlen(optarg));
  			memset(optarg, 'X', strlen(optarg));
  			break;
  #endif
  #ifdef EXTENSIONS
  		case 'r':
  			defaultfield = 1;
  			(void) save_range(&u, optarg);
  			break;
  #endif
  		case 's':
  			defaultfield = 1;
  			memsave(&u.u_shell, optarg, strlen(optarg));
  			break;
  		case 'u':
  			if (!is_number(optarg)) {
  				errx(EXIT_FAILURE, "When using [-u uid], the uid must be numeric");
  			}
  			u.u_uid = atoi(optarg);
  			break;
  #ifdef EXTENSIONS
  		case 'v':
  			verbose = 1;
  			break;
  #endif
  		default:
  			usermgmt_usage("useradd");
  			/* NOTREACHED */
  		}
  	}
  	if (bigD) {
  		if (defaultfield) {
  			checkeuid();
  			return setdefaults(&u) ? EXIT_SUCCESS : EXIT_FAILURE;
  		}
  		(void) printf("group\t\t%s\n", u.u_primgrp);
  		(void) printf("base_dir\t%s\n", u.u_basedir);
  		(void) printf("skel_dir\t%s\n", u.u_skeldir);
  		(void) printf("shell\t\t%s\n", u.u_shell);
  #ifdef EXTENSIONS
  		(void) printf("class\t\t%s\n", u.u_class);
  #endif
  		(void) printf("inactive\t%s\n", (u.u_inactive == NULL) ? UNSET_INACTIVE : u.u_inactive);
  		(void) printf("expire\t\t%s\n", (u.u_expire == NULL) ? UNSET_EXPIRY : u.u_expire);
  #ifdef EXTENSIONS
  		for (i = 0 ; i < u.u_rc ; i++) {
  			(void) printf("range\t\t%d..%d\n", u.u_rv[i].r_from, u.u_rv[i].r_to);
  		}
  #endif
  		return EXIT_SUCCESS;
  	}
  	argc -= optind;
  	argv += optind;
  	if (argc != 1) {
  		usermgmt_usage("useradd");
  	}
  	checkeuid();
  	openlog("useradd", LOG_PID, LOG_USER);
  	return adduser(*argv, &u) ? EXIT_SUCCESS : EXIT_FAILURE;
  }
  
  #ifdef EXTENSIONS
  #define MOD_OPT_EXTENSIONS	"p:vL:"
  #else
  #define MOD_OPT_EXTENSIONS	
  #endif
  
  int
  usermod(int argc, char **argv)
  {
  	user_t	u;
  	char	newuser[MaxUserNameLen + 1];
  	int	c, have_new_user;
  
  	(void) memset(&u, 0, sizeof(u));
  	(void) memset(newuser, 0, sizeof(newuser));
  	read_defaults(&u);
  	free(u.u_primgrp);
  	u.u_primgrp = NULL;
  	have_new_user = 0;
  	while ((c = getopt(argc, argv, "G:c:d:e:f:g:l:mos:u:" MOD_OPT_EXTENSIONS)) != -1) {
  		switch(c) {
  		case 'G':
  			while ((u.u_groupv[u.u_groupc] = strsep(&optarg, ",")) != NULL &&
  			    u.u_groupc < NGROUPS_MAX - 2) {
  				if (u.u_groupv[u.u_groupc][0] != 0) {
  					u.u_groupc++;
  				}
  			}
  			if (optarg != NULL) {
  			  	warnx("Truncated list of secondary groups to %d entries", NGROUPS_MAX - 2);
  			}
  			u.u_flags |= F_SECGROUP;
  			break;
  		case 'c':
  			memsave(&u.u_comment, optarg, strlen(optarg));
  			u.u_flags |= F_COMMENT;
  			break;
  		case 'd':
  			memsave(&u.u_home, optarg, strlen(optarg));
  			u.u_flags |= F_HOMEDIR;
  			break;
  		case 'e':
  			memsave(&u.u_expire, optarg, strlen(optarg));
  			u.u_flags |= F_EXPIRE;
  			break;
  		case 'f':
  			memsave(&u.u_inactive, optarg, strlen(optarg));
  			u.u_flags |= F_INACTIVE;
  			break;
  		case 'g':
  			memsave(&u.u_primgrp, optarg, strlen(optarg));
  			u.u_flags |= F_GROUP;
  			break;
  		case 'l':
  			if (strlcpy(newuser, optarg, sizeof(newuser)) >=
  			    sizeof(newuser))
  				errx(EXIT_FAILURE, "username `%s' too long",
  				    optarg);
  			have_new_user = 1;
  			u.u_flags |= F_USERNAME;
  			break;
  #ifdef EXTENSIONS
  		case 'L':
  			memsave(&u.u_class, optarg, strlen(optarg));
  			u.u_flags |= F_CLASS;
  			break;
  #endif
  		case 'm':
  			u.u_flags |= F_MKDIR;
  			break;
  		case 'o':
  			u.u_flags |= F_DUPUID;
  			break;
  #ifdef EXTENSIONS
  		case 'p':
  			memsave(&u.u_password, optarg, strlen(optarg));
  			memset(optarg, 'X', strlen(optarg));
  			u.u_flags |= F_PASSWORD;
  			break;
  #endif
  		case 's':
  			memsave(&u.u_shell, optarg, strlen(optarg));
  			u.u_flags |= F_SHELL;
  			break;
  		case 'u':
  			if (!is_number(optarg)) {
  				errx(EXIT_FAILURE, "When using [-u uid], the uid must be numeric");
  			}
  			u.u_uid = atoi(optarg);
  			u.u_flags |= F_UID;
  			break;
  #ifdef EXTENSIONS
  		case 'v':
  			verbose = 1;
  			break;
  #endif
  		default:
  			usermgmt_usage("usermod");
  			/* NOTREACHED */
  		}
  	}
  	if ((u.u_flags & F_MKDIR) && !(u.u_flags & F_HOMEDIR) &&
  	    !(u.u_flags & F_USERNAME)) {
  		warnx("option 'm' useless without 'd' or 'l' -- ignored");
  		u.u_flags &= ~F_MKDIR;
  	}
  	argc -= optind;
  	argv += optind;
  	if (argc != 1) {
  		usermgmt_usage("usermod");
  	}
  	checkeuid();
  	openlog("usermod", LOG_PID, LOG_USER);
  	return moduser(*argv, (have_new_user) ? newuser : *argv, &u) ?
  	    EXIT_SUCCESS : EXIT_FAILURE;
  }
  
  #ifdef EXTENSIONS
  #define DEL_OPT_EXTENSIONS	"Dp:v"
  #else
  #define DEL_OPT_EXTENSIONS	
  #endif
  
  int
  userdel(int argc, char **argv)
  {
  	struct passwd	*pwp;
  	user_t		u;
  	char		password[PasswordLength + 1];
  	int		defaultfield;
  	int		rmhome;
  	int		bigD;
  	int		c;
  
  	(void) memset(&u, 0, sizeof(u));
  	read_defaults(&u);
  	defaultfield = bigD = rmhome = 0;
  	while ((c = getopt(argc, argv, "r" DEL_OPT_EXTENSIONS)) != -1) {
  		switch(c) {
  #ifdef EXTENSIONS
  		case 'D':
  			bigD = 1;
  			break;
  #endif
  #ifdef EXTENSIONS
  		case 'p':
  			defaultfield = 1;
  			u.u_preserve = (strcmp(optarg, "true") == 0) ? 1 :
  					(strcmp(optarg, "yes") == 0) ? 1 :
  					 atoi(optarg);
  			break;
  #endif
  		case 'r':
  			rmhome = 1;
  			break;
  #ifdef EXTENSIONS
  		case 'v':
  			verbose = 1;
  			break;
  #endif
  		default:
  			usermgmt_usage("userdel");
  			/* NOTREACHED */
  		}
  	}
  #ifdef EXTENSIONS
  	if (bigD) {
  		if (defaultfield) {
  			checkeuid();
  			return setdefaults(&u) ? EXIT_SUCCESS : EXIT_FAILURE;
  		}
  		(void) printf("preserve\t%s\n", (u.u_preserve) ? "true" : "false");
  		return EXIT_SUCCESS;
  	}
  #endif
  	argc -= optind;
  	argv += optind;
  	if (argc != 1) {
  		usermgmt_usage("userdel");
  	}
  	checkeuid();
  	if ((pwp = getpwnam(*argv)) == NULL) {
  		warnx("No such user `%s'", *argv);
  		return EXIT_FAILURE;
  	}
  	if (rmhome)
  		(void)removehomedir(pwp->pw_name, pwp->pw_uid, pwp->pw_dir);
  	if (u.u_preserve) {
  		u.u_flags |= F_SHELL;
  		memsave(&u.u_shell, NOLOGIN, strlen(NOLOGIN));
  		(void) memset(password, '*', DES_Len);
  		password[DES_Len] = 0;
  		memsave(&u.u_password, password, strlen(password));
  		u.u_flags |= F_PASSWORD;
  		openlog("userdel", LOG_PID, LOG_USER);
  		return moduser(*argv, *argv, &u) ? EXIT_SUCCESS : EXIT_FAILURE;
  	}
  	if (!rm_user_from_groups(*argv)) {
  		return 0;
  	}
  	openlog("userdel", LOG_PID, LOG_USER);
  	return moduser(*argv, *argv, NULL) ? EXIT_SUCCESS : EXIT_FAILURE;
  }
  
  #ifdef EXTENSIONS
  #define GROUP_ADD_OPT_EXTENSIONS	"v"
  #else
  #define GROUP_ADD_OPT_EXTENSIONS	
  #endif
  
  /* add a group */
  int
  groupadd(int argc, char **argv)
  {
  	int	dupgid;
  	int	gid;
  	int	c;
  
  	gid = GID_MAX;
  	dupgid = 0;
  	while ((c = getopt(argc, argv, "g:o" GROUP_ADD_OPT_EXTENSIONS)) != -1) {
  		switch(c) {
  		case 'g':
  			if (!is_number(optarg)) {
  				errx(EXIT_FAILURE, "When using [-g gid], the gid must be numeric");
  			}
  			gid = atoi(optarg);
  			break;
  		case 'o':
  			dupgid = 1;
  			break;
  #ifdef EXTENSIONS
  		case 'v':
  			verbose = 1;
  			break;
  #endif
  		default:
  			usermgmt_usage("groupadd");
  			/* NOTREACHED */
  		}
  	}
  	argc -= optind;
  	argv += optind;
  	if (argc != 1) {
  		usermgmt_usage("groupadd");
  	}
  	checkeuid();
  	if (!valid_group(*argv)) {
  		errx(EXIT_FAILURE, "invalid group name `%s'", *argv);
  	}
  	if (gid < 0 && !getnextgid(&gid, LowGid, HighGid)) {
  		errx(EXIT_FAILURE, "can't add group: can't get next gid");
  	}
  	if (!dupgid && getgrgid((gid_t) gid) != NULL) {
  		errx(EXIT_FAILURE, "can't add group: gid %d is a duplicate", gid);
  	}
  	openlog("groupadd", LOG_PID, LOG_USER);
  	if (!creategid(*argv, gid, "")) {
  		errx(EXIT_FAILURE, "can't add group: problems with %s file",
  		    _PATH_GROUP);
  	}
  	return EXIT_SUCCESS;
  }
  
  #ifdef EXTENSIONS
  #define GROUP_DEL_OPT_EXTENSIONS	"v"
  #else
  #define GROUP_DEL_OPT_EXTENSIONS	
  #endif
  
  /* remove a group */
  int
  groupdel(int argc, char **argv)
  {
  	int	c;
  
  	while ((c = getopt(argc, argv, "" GROUP_DEL_OPT_EXTENSIONS)) != -1) {
  		switch(c) {
  #ifdef EXTENSIONS
  		case 'v':
  			verbose = 1;
  			break;
  #endif
  		default:
  			usermgmt_usage("groupdel");
  			/* NOTREACHED */
  		}
  	}
  	argc -= optind;
  	argv += optind;
  	if (argc != 1) {
  		usermgmt_usage("groupdel");
  	}
  	checkeuid();
  	openlog("groupdel", LOG_PID, LOG_USER);
  	if (getgrnam(*argv) == NULL) {
  		warnx("No such group: `%s'", *argv);
  		return EXIT_FAILURE;
  	}
  	if (!modify_gid(*argv, NULL)) {
  		err(EXIT_FAILURE, "can't change %s file", _PATH_GROUP);
  	}
  	return EXIT_SUCCESS;
  }
  
  #ifdef EXTENSIONS
  #define GROUP_MOD_OPT_EXTENSIONS	"v"
  #else
  #define GROUP_MOD_OPT_EXTENSIONS	
  #endif
  
  /* modify a group */
  int
  groupmod(int argc, char **argv)
  {
  	struct group	*grp;
  	char		buf[LINE_MAX];
  	char		*newname;
  	char		**cpp;
  	int		dupgid;
  	int		gid;
  	int		cc;
  	int		c;
  
  	gid = GID_MAX;
  	dupgid = 0;
  	newname = NULL;
  	while ((c = getopt(argc, argv, "g:on:" GROUP_MOD_OPT_EXTENSIONS)) != -1) {
  		switch(c) {
  		case 'g':
  			if (!is_number(optarg)) {
  				errx(EXIT_FAILURE, "When using [-g gid], the gid must be numeric");
  			}
  			gid = atoi(optarg);
  			break;
  		case 'o':
  			dupgid = 1;
  			break;
  		case 'n':
  			memsave(&newname, optarg, strlen(optarg));
  			break;
  #ifdef EXTENSIONS
  		case 'v':
  			verbose = 1;
  			break;
  #endif
  		default:
  			usermgmt_usage("groupmod");
  			/* NOTREACHED */
  		}
  	}
  	argc -= optind;
  	argv += optind;
  	if (argc != 1) {
  		usermgmt_usage("groupmod");
  	}
  	checkeuid();
  	if (gid < 0 && newname == NULL) {
  		errx(EXIT_FAILURE, "Nothing to change");
  	}
  	if (dupgid && gid < 0) {
  		errx(EXIT_FAILURE, "Duplicate which gid?");
  	}
  	if ((grp = getgrnam(*argv)) == NULL) {
  		errx(EXIT_FAILURE, "can't find group `%s' to modify", *argv);
  	}
  	if (!is_local(*argv, _PATH_GROUP)) {
  		errx(EXIT_FAILURE, "Group `%s' must be a local group", *argv);
  	}
  	if (newname != NULL && !valid_group(newname)) {
  		errx(EXIT_FAILURE, "invalid group name `%s'", newname);
  	}
  	if ((cc = snprintf(buf, sizeof(buf), "%s:%s:%u:",
  	    (newname) ? newname : grp->gr_name, grp->gr_passwd,
  	    (gid < 0) ? grp->gr_gid : gid)) >= sizeof(buf) || cc < 0)
  		errx(EXIT_FAILURE, "group `%s' entry too long", grp->gr_name);
  
  	for (cpp = grp->gr_mem ; *cpp ; cpp++) {
  		cc = strlcat(buf, *cpp, sizeof(buf)) + 1;
  		if (cc >= sizeof(buf))
  			errx(EXIT_FAILURE, "group `%s' entry too long",
  			    grp->gr_name);
  		if (cpp[1] != NULL) {
  			buf[cc - 1] = ',';
  			buf[cc] = '\0';
  		}
  	}
  	cc = strlcat(buf, "\n", sizeof(buf));
  	if (cc >= sizeof(buf))
  		errx(EXIT_FAILURE, "group `%s' entry too long", grp->gr_name);
  
  	openlog("groupmod", LOG_PID, LOG_USER);
  	if (!modify_gid(*argv, buf))
  		err(EXIT_FAILURE, "can't change %s file", _PATH_GROUP);
  	return EXIT_SUCCESS;
  }
  
  #ifdef EXTENSIONS
  /* display user information */
  int
  userinfo(int argc, char **argv)
  {
  	struct passwd	*pwp;
  	struct group	*grp;
  	char		**cpp;
  	int		exists;
  	int		i;
  
  	exists = 0;
  	while ((i = getopt(argc, argv, "ev")) != -1) {
  		switch(i) {
  		case 'e':
  			exists = 1;
  			break;
  		case 'v':
  			verbose = 1;
  			break;
  		default:
  			usermgmt_usage("userinfo");
  			/* NOTREACHED */
  		}
  	}
  	argc -= optind;
  	argv += optind;
  	if (argc != 1) {
  		usermgmt_usage("userinfo");
  	}
  	pwp = find_user_info(*argv);
  	if (exists) {
  		exit((pwp) ? EXIT_SUCCESS : EXIT_FAILURE);
  	}
  	if (pwp == NULL) {
  		errx(EXIT_FAILURE, "can't find user `%s'", *argv);
  	}
  	(void) printf("login\t%s\n", pwp->pw_name);
  	(void) printf("passwd\t%s\n", pwp->pw_passwd);
  	(void) printf("uid\t%u\n", pwp->pw_uid);
  	if ((grp = getgrgid(pwp->pw_gid)) == NULL)
  		(void) printf("groups\t%u", pwp->pw_gid);
  	else
  		(void) printf("groups\t%s", grp->gr_name);
  	while ((grp = getgrent()) != NULL) {
  		for (cpp = grp->gr_mem ; *cpp ; cpp++) {
  			if (strcmp(*cpp, pwp->pw_name) == 0 &&
  			    grp->gr_gid != pwp->pw_gid)
  				(void) printf(" %s", grp->gr_name);
  		}
  	}
  	(void) fputc('\n', stdout);
  	(void) printf("change\t%s", pwp->pw_change ? ctime(&pwp->pw_change) : "NEVER\n");
  #ifdef EXTENSIONS
  	(void) printf("class\t%s\n", pwp->pw_class);
  #endif
  	(void) printf("gecos\t%s\n", pwp->pw_gecos);
  	(void) printf("dir\t%s\n", pwp->pw_dir);
  	(void) printf("shell\t%s\n", pwp->pw_shell);
  	(void) printf("expire\t%s", pwp->pw_expire ? ctime(&pwp->pw_expire) : "NEVER\n");
  	return EXIT_SUCCESS;
  }
  #endif
  
  #ifdef EXTENSIONS
  /* display user information */
  int
  groupinfo(int argc, char **argv)
  {
  	struct group	*grp;
  	char		**cpp;
  	int		exists;
  	int		i;
  
  	exists = 0;
  	while ((i = getopt(argc, argv, "ev")) != -1) {
  		switch(i) {
  		case 'e':
  			exists = 1;
  			break;
  		case 'v':
  			verbose = 1;
  			break;
  		default:
  			usermgmt_usage("groupinfo");
  			/* NOTREACHED */
  		}
  	}
  	argc -= optind;
  	argv += optind;
  	if (argc != 1) {
  		usermgmt_usage("groupinfo");
  	}
  	grp = find_group_info(*argv);
  	if (exists) {
  		exit((grp) ? EXIT_SUCCESS : EXIT_FAILURE);
  	}
  	if (grp == NULL) {
  		errx(EXIT_FAILURE, "can't find group `%s'", *argv);
  	}
  	(void) printf("name\t%s\n", grp->gr_name);
  	(void) printf("passwd\t%s\n", grp->gr_passwd);
  	(void) printf("gid\t%u\n", grp->gr_gid);
  	(void) printf("members\t");
  	for (cpp = grp->gr_mem ; *cpp ; cpp++) {
  		(void) printf("%s ", *cpp);
  	}
  	(void) fputc('\n', stdout);
  	return EXIT_SUCCESS;
  }
  #endif
  