/*
 * Copyright 1991 - 1994, Julianne Frances Haugh
 * 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. Neither the name of Julianne F. Haugh 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 JULIE HAUGH 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 JULIE HAUGH OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <config.h>

#include "rcsid.h"
RCSID("$Id: useradd.c,v 1.13 1998/04/16 19:57:51 marekm Exp $")

#include "prototypes.h"
#include "defines.h"
#include "chkname.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <errno.h>
#include <pwd.h>
#include <grp.h>
#include <ctype.h>
#include <fcntl.h>
#include <time.h>

#include "pwauth.h"
#if HAVE_LASTLOG_H
#include <lastlog.h>
#else
#include "lastlog_.h"
#endif
#include "faillog.h"

#ifndef SKEL_DIR
#define SKEL_DIR "/etc/skel"
#endif

#ifndef USER_DEFAULTS_FILE
#define USER_DEFAULTS_FILE "/etc/default/useradd"
#define NEW_USER_FILE "/etc/default/nuaddXXXXXX"
#endif

/*
 * Needed for MkLinux DR1/2/2.1 - J.
 */
#ifndef LASTLOG_FILE
#define LASTLOG_FILE "/var/log/lastlog"
#endif

/*
 * These defaults are used if there is no defaults file.
 */
static gid_t def_group = 100;
static char *def_gname = "other";
static char *def_home = "/home";
static char *def_shell = "";
static char *def_template = SKEL_DIR;
#ifdef SHADOWPWD
static long def_inactive = -1;
static char *def_expire = "";
#endif

static char	def_file[] = USER_DEFAULTS_FILE;

#define	VALID(s)	(strcspn (s, ":\n") == strlen (s))

static char *user_name = "";
static char *user_pass = "!";
static uid_t user_id;
static gid_t user_gid;
static char *user_comment = "";
static char *user_home = "";
static char *user_shell = "";
#ifdef	SHADOWPWD
static long user_expire = -1;
static int is_shadow_pwd;
#endif
#ifdef SHADOWGRP
static int is_shadow_grp;
#endif
static char *user_groups[NGROUPS_MAX+1];  /* NULL-terminated list */
static int do_grp_update = 0;  /* group files need to be updated */

static char	*Prog;

static int
	uflg = 0, /* specify user ID for new account */
	oflg = 0, /* permit non-unique user ID to be specified with -u */
	gflg = 0, /* primary group ID for new account */
	Gflg = 0, /* secondary group set for new account */
	dflg = 0, /* home directory for new account */
	bflg = 0, /* new default root of home directory */
	sflg = 0, /* shell program for new account */
	cflg = 0, /* comment (GECOS) field for new account */
	mflg = 0, /* create user's home directory if it doesn't exist */
	kflg = 0, /* specify a directory to fill new user directory */
	fflg = 0, /* days until account with expired password is locked */
	eflg = 0, /* days since 1970-01-01 when account is locked */
	Dflg = 0; /* set/show new user default values */

#ifdef AUTH_METHODS
static int Aflg = 0; /* specify authentication method for user */
static char user_auth[1024];
static char *auth_arg;
#endif

extern char *optarg;
extern int optind;

#ifdef NDBM
extern	int	pw_dbm_mode;
#ifdef	SHADOWPWD
extern	int	sp_dbm_mode;
#endif
extern	int	gr_dbm_mode;
#ifdef	SHADOWGRP
extern	int	sg_dbm_mode;
#endif
#endif

static int	home_added;

#ifdef NDBM
static int	pw_dbm_added;
static int	gr_dbm_added;
#ifdef	SHADOWPWD
static int	sp_dbm_added;
#endif
#ifdef	SHADOWGRP
static int	sg_dbm_added;
#endif
#endif	/* NDBM */

#include "groupio.h"

#ifdef	SHADOWGRP
#include "sgroupio.h"
#endif

#include "pwio.h"

#ifdef	SHADOWPWD
#include "shadowio.h"
#endif

#include "getdef.h"

/*
 * exit status values
 */
#define E_SUCCESS	0	/* success */
#define E_PW_UPDATE	1	/* can't update password file */
#define E_USAGE		2	/* bad command syntax */
#define E_BAD_ARG	3	/* invalid argument to option */
#define E_UID_IN_USE	4	/* uid already in use (and no -o) */
#define E_NOTFOUND	6	/* specified group doesn't exist */
#define E_NAME_IN_USE	9	/* username already in use */
#define E_GRP_UPDATE	10	/* can't update group file */
#define E_HOMEDIR	12	/* can't create home directory */

#ifdef SVR4
#define DGROUP	"defgroup="
#define HOME	"defparent="
#define SHELL	"defshell="
#define INACT	"definact="
#define EXPIRE	"defexpire="
#define SKEL	"defskel="
#else
#define DGROUP	"GROUP="
#define HOME	"HOME="
#define SHELL	"SHELL="
#define INACT	"INACTIVE="
#define EXPIRE	"EXPIRE="
#define SKEL	"SKEL="
#endif

/* local function prototypes */
static void fail_exit P_((int));
static struct group *getgr_nam_gid P_((const char *));
static long get_number P_((const char *));
static void get_defaults P_((void));
static void show_defaults P_((void));
static int set_defaults P_((void));
static int get_groups P_((char *));
static void usage P_((void));
static void new_pwent P_((struct passwd *));
#ifdef SHADOWPWD
static long scale_age P_((long));
static void new_spent P_((struct spwd *));
#endif
static void grp_update P_((void));
static void find_new_uid P_((void));
#ifdef AUTH_METHODS
static void convert_auth P_((char *, const char *));
static int valid_auth P_((const char *));
#endif
static void process_flags P_((int argc, char **argv));
static void close_files P_((void));
static void open_files P_((void));
static void faillog_reset P_((uid_t));
static void lastlog_reset P_((uid_t));
static void usr_update P_((void));
static void create_home P_((void));
int main P_((int, char **));

/*
 * fail_exit - undo as much as possible
 */

static void
fail_exit(int code)
{
#ifdef NDBM
	struct	passwd	pwent;

	if (pw_dbm_added) {
		pwent.pw_name = user_name;
		pwent.pw_uid = user_id;
		pw_dbm_remove(&pwent);
	}
	if (gr_dbm_added)
		fprintf(stderr, "%s: rebuild the group database\n", Prog);
#ifdef	SHADOWPWD
	if (sp_dbm_added)
		sp_dbm_remove(user_name);
#endif
#ifdef	SHADOWGRP
	if (sg_dbm_added)
		fprintf(stderr, "%s: rebuild the shadow group database\n",
			Prog);
#endif
#endif	/* NDBM */
	if (home_added)
		rmdir(user_home);

	SYSLOG((LOG_INFO, "failed adding user `%s', data deleted\n",
		user_name));
	exit(code);
}


static struct group *
getgr_nam_gid(const char *name)
{
	gid_t gid;
	char *ep;

	gid = strtol(name, &ep, 10);
	if (*name != '\0' && *ep == '\0')  /* valid numeric gid */
		return getgrgid(gid);

	return getgrnam(name);
}


static long
get_number(const char *cp)
{
	long val;
	char *ep;

	val = strtol(cp, &ep, 10);
	if (*cp != '\0' && *ep == '\0')  /* valid number */
		return val;

	fprintf(stderr, "%s: invalid numeric argument `%s'\n", Prog, cp);
	exit(E_BAD_ARG);
}

#define MATCH(x,y) (strncmp((x),(y),strlen(y)) == 0)

/*
 * get_defaults - read the defaults file
 *
 *	get_defaults() reads the defaults file for this command.  It sets
 *	the various values from the file, or uses built-in default values
 *	if the file does not exist.
 */

static void
get_defaults(void)
{
	FILE *fp;
	char buf[1024];
	char *cp, *ep;
	const struct group *grp;
	long val;

	/*
	 * Open the defaults file for reading.
	 */

	if (!(fp = fopen(def_file, "r")))
		return;

	/*
	 * Read the file a line at a time.  Only the lines that have
	 * relevant values are used, everything else can be ignored.
	 */

	while (fgets(buf, sizeof buf, fp)) {
		if ((cp = strrchr (buf, '\n')))
			*cp = '\0';

		if (!(cp = strchr(buf, '=')))
			continue;

		cp++;

		/*
		 * Primary GROUP identifier
		 */

		if (MATCH(buf, DGROUP)) {
			val = strtol(cp, &ep, 10);
			if (*cp != '\0' && *ep == '\0') {  /* valid number */
				def_group = val;
				if ((grp = getgrgid(def_group))) {
					def_gname = xstrdup(grp->gr_name);
				} else {
					fprintf(stderr, "%s: unknown gid %s\n",
						Prog, cp);
				}
			} else if ((grp = getgrnam(cp))) {
				def_group = grp->gr_gid;
				def_gname = xstrdup(cp);
			} else {
				fprintf(stderr, "%s: unknown group %s\n",
					Prog, cp);
			}
		}
		
		/*
		 * Default HOME filesystem
		 */
		 
		else if (MATCH(buf, HOME)) {
			def_home = xstrdup(cp);
		}

		/*
		 * Default Login Shell command
		 */

		else if (MATCH(buf, SHELL)) {
			def_shell = xstrdup(cp);
		}

#ifdef SHADOWPWD
		/*
		 * Default Password Inactive value
		 */

		else if (MATCH(buf, INACT)) {
			val = strtol(cp, &ep, 10);
			if (*cp != '\0' && *ep == '\0')  /* valid number */
				def_inactive = val;
			else
				def_inactive = -1;
		}
		
		/*
		 * Default account expiration date
		 */

		else if (MATCH(buf, EXPIRE)) {
			def_expire = xstrdup(cp);
		}
#endif

		/*
		 * Default Skeleton information
		 */

		else if (MATCH(buf, SKEL)) {
			if (*cp == '\0')
				cp = SKEL_DIR;
			
			def_template = xstrdup(cp);
		}
	}
}


/*
 * show_defaults - show the contents of the defaults file
 *
 *	show_defaults() displays the values that are used from the default
 *	file and the built-in values.
 */

static void
show_defaults(void)
{
#ifdef SVR4
	printf("group=%s,%ld  basedir=%s  skel=%s\n",
		def_gname, (long) def_group, def_home, def_template);

	printf("shell=%s  ", def_shell);
#ifdef SHADOWPWD
	printf("inactive=%ld  expire=%s", def_inactive, def_expire);
#endif
	printf("\n");
#else /* !SVR4 */
	printf("GROUP=%ld\n", (long) def_group);
	printf("HOME=%s\n", def_home);
#ifdef SHADOWPWD
	printf("INACTIVE=%ld\n", def_inactive);
	printf("EXPIRE=%s\n", def_expire);
#endif
	printf("SHELL=%s\n", def_shell);
	printf("SKEL=%s\n", def_template);
#endif /* !SVR4 */
}

/*
 * set_defaults - write new defaults file
 *
 *	set_defaults() re-writes the defaults file using the values that
 *	are currently set.  Duplicated lines are pruned, missing lines are
 *	added, and unrecognized lines are copied as is.
 */

static int
set_defaults(void)
{
	FILE	*ifp;
	FILE	*ofp;
	char	buf[1024];
	static	char	new_file[] = NEW_USER_FILE;
	char	*cp;
	int	out_group = 0;
	int	out_home = 0;
	int	out_inactive = 0;
	int	out_expire = 0;
	int	out_shell = 0;
	int	out_skel = 0;
#ifdef	SVR4
	int	out_gname = 0;
#endif

	/*
	 * Create a temporary file to copy the new output to.
	 */

	mktemp (new_file);
	if (!(ofp = fopen (new_file, "w"))) {
		fprintf (stderr, "%s: cannot create new defaults file\n", Prog);
		return -1;
	}

	/*
	 * Open the existing defaults file and copy the lines to the
	 * temporary file, using any new values.  Each line is checked
	 * to insure that it is not output more than once.
	 */

	if (!(ifp = fopen(def_file, "r"))) {
		fprintf(ofp, "# useradd defaults file\n");
		goto skip;
	}

	while (fgets(buf, sizeof buf, ifp)) {
		if ((cp = strrchr(buf, '\n')))
			*cp = '\0';

		if (!out_group && MATCH(buf, DGROUP)) {
			fprintf(ofp, DGROUP "%d\n", (int) def_group);
			out_group++;
		}
#ifdef	SVR4
		else if (!out_gname && MATCH(buf, "defgname=")) {
			fprintf(ofp, "defgname=%s\n", def_gname);
			out_gname++;
		}
#endif
		else if (!out_home && MATCH(buf, HOME)) {
			fprintf(ofp, HOME "%s\n", def_home);
			out_home++;
#ifdef	SHADOWPWD
		} else if (!out_inactive && MATCH(buf, INACT)) {
			fprintf(ofp, INACT "%ld\n", def_inactive);
			out_inactive++;
		} else if (!out_expire && MATCH(buf, EXPIRE)) {
			fprintf(ofp, EXPIRE "%s\n", def_expire);
			out_expire++;
		}
#endif
		else if (!out_shell && MATCH(buf, SHELL)) {
			fprintf(ofp, SHELL "%s\n", def_shell);
			out_shell++;
		}
		else if (!out_skel && MATCH(buf, SKEL)) {
			fprintf(ofp, SKEL "%s\n", def_template);
			out_skel++;
		}
		else
			fprintf(ofp, "%s\n", buf);
	}
	fclose(ifp);

skip:
	/*
	 * Check each line to insure that every line was output.  This
	 * causes new values to be added to a file which did not previously
	 * have an entry for that value.
	 */

	if (!out_group)
		fprintf(ofp, DGROUP "%d\n", (int) def_group);
	if (!out_home)
		fprintf(ofp, HOME "%s\n", def_home);
#ifdef	SHADOWPWD
	if (!out_inactive)
		fprintf(ofp, INACT "%ld\n", def_inactive);
	if (!out_expire)
		fprintf(ofp, EXPIRE "%s\n", def_expire);
#endif
	if (!out_shell)
		fprintf(ofp, SHELL "%s\n", def_shell);
	if (!out_skel)
		fprintf(ofp, SKEL "%s\n", def_template);

	/*
	 * Flush and close the file.  Check for errors to make certain
	 * the new file is intact.
	 */

	fflush(ofp);
	if (ferror(ofp) || fclose(ofp)) {
		unlink(new_file);
		return -1;
	}

	/*
	 * Rename the current default file to its backup name.
	 */

	snprintf(buf, sizeof buf, "%s-", def_file);
	if (rename(def_file, buf) && errno != ENOENT) {
		snprintf(buf, sizeof buf, "%s: rename: %s", Prog, def_file);
		perror(buf);
		unlink(new_file);
		return -1;
	}

	/*
	 * Rename the new default file to its correct name.
	 */

	if (rename(new_file, def_file)) {
		snprintf(buf, sizeof buf, "%s: rename: %s", Prog, new_file);
		perror(buf);
		return -1;
	}
#ifdef SHADOWPWD
	SYSLOG((LOG_INFO,
		"defaults: group=%d, home=%s, inactive=%ld, expire=%s\n",
		(int) def_group, def_home, def_inactive, def_expire));
#else
	SYSLOG((LOG_INFO, "defaults: group=%d, home=%s\n",
		(int) def_group, def_home));
#endif
	return 0;
}

/*
 * get_groups - convert a list of group names to an array of group IDs
 *
 *	get_groups() takes a comma-separated list of group names and
 *	converts it to a NULL-terminated array.  Any unknown group
 *	names are reported as errors.
 */

static int
get_groups(char *list)
{
	char *cp;
	const struct group *grp;
	int errors = 0;
	int ngroups = 0;

	/*
	 * Initialize the list to be empty
	 */

	user_groups[0] = (char *) 0;

	if (! *list)
		return 0;

	/*
	 * So long as there is some data to be converted, strip off
	 * each name and look it up.  A mix of numerical and string
	 * values for group identifiers is permitted.
	 */

	do {
		/*
		 * Strip off a single name from the list
		 */

		if ((cp = strchr (list, ',')))
			*cp++ = '\0';

		/*
		 * Names starting with digits are treated as numerical
		 * GID values, otherwise the string is looked up as is.
		 */

		grp = getgr_nam_gid(list);

		/*
		 * There must be a match, either by GID value or by
		 * string name.
		 */

		if (! grp) {
			fprintf (stderr, "%s: unknown group %s\n", Prog, list);
			errors++;
		}
		list = cp;

		/*
		 * If the group doesn't exist, don't dump core...
		 * Instead, try the next one.  --marekm
		 */
		if (! grp)
			continue;

#ifdef	USE_NIS
		/*
		 * Don't add this group if they are an NIS group.  Tell
		 * the user to go to the server for this group.
		 */

		if (__isgrNIS ()) {
			fprintf (stderr, "%s: group `%s' is a NIS group.\n",
				Prog, grp->gr_name);
			continue;
		}
#endif

		if (ngroups == NGROUPS_MAX) {
			fprintf(stderr,
				"%s: too many groups specified (max %d).\n",
				Prog, ngroups);
			break;
		}

		/*
		 * Add the group name to the user's list of groups.
		 */

		user_groups[ngroups++] = xstrdup(grp->gr_name);
	} while (list);

	user_groups[ngroups] = (char *) 0;

	/*
	 * Any errors in finding group names are fatal
	 */

	if (errors)
		return -1;

	return 0;
}

/*
 * usage - display usage message and exit
 */

static void
usage(void)
{
	fprintf(stderr,
		"usage: %s\t[-u uid [-o]] [-g group] [-G group,...] \n", Prog);
	fprintf(stderr,
		"\t\t[-d home] [-s shell] [-c comment] [-m [-k template]]\n");
	fprintf(stderr, "\t\t");
#ifdef SHADOWPWD
	fprintf(stderr, "[-f inactive] [-e expire %s] ", DATE_FORMAT_DESCR);
#endif
#ifdef AUTH_METHODS
	fprintf(stderr, "[-A program] ");
#endif
	fprintf(stderr, "[-p passwd] name\n");

	fprintf(stderr, "       %s\t-D [-g group] [-b base] [-s shell]"
#ifdef SHADOWPWD
		" [-f inactive] [-e expire %s]\n",
#endif
		Prog, DATE_FORMAT_DESCR);

	exit(E_USAGE);
}

/*
 * new_pwent - initialize the values in a password file entry
 *
 *	new_pwent() takes all of the values that have been entered and
 *	fills in a (struct passwd) with them.
 */

static void
new_pwent(struct passwd *pwent)
{
	memzero(pwent, sizeof *pwent);
	pwent->pw_name = user_name;
#ifdef SHADOWPWD
	if (is_shadow_pwd)
		pwent->pw_passwd = SHADOW_PASSWD_STRING;
	else
#endif
	pwent->pw_passwd = user_pass;

#ifdef ATT_AGE
	pwent->pw_age = "";
#endif
	pwent->pw_uid = user_id;
	pwent->pw_gid = user_gid;
	pwent->pw_gecos = user_comment;
#ifdef	ATT_COMMENT
	pwent->pw_comment = "";
#endif
#ifdef BSD_QUOTA
	pwent->pw_quota = "";
#endif
	pwent->pw_dir = user_home;
	pwent->pw_shell = user_shell;
}

#ifdef SHADOWPWD
static long
scale_age(long x)
{
	if (x <= 0)
		return x;

	return x * (DAY/SCALE);
}

/*
 * new_spent - initialize the values in a shadow password file entry
 *
 *	new_spent() takes all of the values that have been entered and
 *	fills in a (struct spwd) with them.
 */

static void
new_spent(struct spwd *spent)
{
	memzero(spent, sizeof *spent);
	spent->sp_namp = user_name;
	spent->sp_pwdp = user_pass;
	spent->sp_lstchg = time((time_t *) 0) / SCALE;
	spent->sp_min = scale_age(getdef_num("PASS_MIN_DAYS", -1));
	spent->sp_max = scale_age(getdef_num("PASS_MAX_DAYS", -1));
	spent->sp_warn = scale_age(getdef_num("PASS_WARN_AGE", -1));
	spent->sp_inact = scale_age(def_inactive);
	spent->sp_expire = scale_age(user_expire);
	spent->sp_flag = -1;
}
#endif

/*
 * grp_update - add user to secondary group set
 *
 *	grp_update() takes the secondary group set given in user_groups
 *	and adds the user to each group given by that set.
 */

static void
grp_update(void)
{
	const struct group *grp;
	struct group *ngrp;
#ifdef	SHADOWGRP
	const struct sgrp *sgrp;
	struct sgrp *nsgrp;
#endif

	/*
	 * Lock and open the group file.  This will load all of the group
	 * entries.
	 */

	if (! gr_lock ()) {
		fprintf (stderr, "%s: error locking group file\n", Prog);
		fail_exit(E_GRP_UPDATE);
	}
	if (! gr_open (O_RDWR)) {
		fprintf (stderr, "%s: error opening group file\n", Prog);
		fail_exit(E_GRP_UPDATE);
	}
#ifdef	SHADOWGRP
	if (is_shadow_grp && ! sgr_lock ()) {
		fprintf (stderr, "%s: error locking shadow group file\n", Prog);
		fail_exit(E_GRP_UPDATE);
	}
	if (is_shadow_grp && ! sgr_open (O_RDWR)) {
		fprintf (stderr, "%s: error opening shadow group file\n", Prog);
		fail_exit(E_GRP_UPDATE);
	}
#endif

	/*
	 * Scan through the entire group file looking for the groups that
	 * the user is a member of.
	 */

	for (gr_rewind (), grp = gr_next ();grp;grp = gr_next ()) {

		/*
		 * See if the user specified this group as one of their
		 * concurrent groups.
		 */

		if (!is_on_list(user_groups, grp->gr_name))
			continue;

		/*
		 * Make a copy - gr_update() will free() everything
		 * from the old entry, and we need it later.
		 */

		ngrp = __gr_dup(grp);
		if (!ngrp) {
			fail_exit(E_GRP_UPDATE);  /* XXX */
		}

		/* 
		 * Add the username to the list of group members and
		 * update the group entry to reflect the change.
		 */

		ngrp->gr_mem = add_list (ngrp->gr_mem, user_name);
		if (!gr_update(ngrp)) {
			fprintf(stderr, "%s: error adding new group entry\n",
				Prog);
			fail_exit(E_GRP_UPDATE);
		}
#ifdef	NDBM
		/*
		 * Update the DBM group file with the new entry as well.
		 */

		if (!gr_dbm_update(ngrp)) {
			fprintf(stderr, "%s: cannot add new dbm group entry\n",
				Prog);
			fail_exit(E_GRP_UPDATE);
		} else
			gr_dbm_added++;
#endif
		SYSLOG((LOG_INFO, "add `%s' to group `%s'\n",
			user_name, ngrp->gr_name));
	}
#ifdef NDBM
	endgrent ();
#endif

#ifdef	SHADOWGRP
	if (!is_shadow_grp)
		return;

	/*
	 * Scan through the entire shadow group file looking for the groups
	 * that the user is a member of.  The administrative list isn't
	 * modified.
	 */

	for (sgr_rewind (), sgrp = sgr_next ();sgrp;sgrp = sgr_next ()) {

		/*
		 * See if the user specified this group as one of their
		 * concurrent groups.
		 */

		if (!gr_locate(sgrp->sg_name))
			continue;

		if (!is_on_list(user_groups, sgrp->sg_name))
			continue;

		/*
		 * Make a copy - sgr_update() will free() everything
		 * from the old entry, and we need it later.
		 */

		nsgrp = __sgr_dup(sgrp);
		if (!nsgrp) {
			fail_exit(E_GRP_UPDATE);  /* XXX */
		}

		/* 
		 * Add the username to the list of group members and
		 * update the group entry to reflect the change.
		 */

		nsgrp->sg_mem = add_list (nsgrp->sg_mem, user_name);
		if (!sgr_update(nsgrp)) {
			fprintf(stderr, "%s: error adding new group entry\n",
				Prog);
			fail_exit(E_GRP_UPDATE);
		}
#ifdef	NDBM
		/*
		 * Update the DBM group file with the new entry as well.
		 */

		if (!sg_dbm_update(nsgrp)) {
			fprintf(stderr, "%s: cannot add new dbm group entry\n",
				Prog);
			fail_exit(E_GRP_UPDATE);
		} else
			sg_dbm_added++;
#endif	/* NDBM */
		SYSLOG((LOG_INFO, "add `%s' to shadow group `%s'\n",
			user_name, nsgrp->sg_name));
	}
#ifdef NDBM
	endsgent ();
#endif	/* NDBM */
#endif	/* SHADOWGRP */
}

/*
 * find_new_uid - find the next available UID
 *
 *	find_new_uid() locates the next highest unused UID in the password
 *	file, or checks the given user ID against the existing ones for
 *	uniqueness.
 */

static void
find_new_uid(void)
{
	const struct passwd *pwd;
	uid_t uid_min, uid_max;

	uid_min = getdef_num("UID_MIN", 100);
	uid_max = getdef_num("UID_MAX", 60000);

	/*
	 * Start with some UID value if the user didn't provide us with
	 * one already.
	 */

	if (! uflg)
		user_id = uid_min;

	/*
	 * Search the entire password file, either looking for this
	 * UID (if the user specified one with -u) or looking for the
	 * largest unused value.
	 */

#ifdef NO_GETPWENT
	pw_rewind();
	while ((pwd = pw_next())) {
#else  /* using getpwent() we can check against NIS users etc.  */
	setpwent();
	while ((pwd = getpwent())) {
#endif
		if (strcmp(user_name, pwd->pw_name) == 0) {
			fprintf (stderr, "%s: name %s is not unique\n",
				Prog, user_name);
			exit(E_NAME_IN_USE);
		}
		if (uflg && user_id == pwd->pw_uid) {
			fprintf (stderr, "%s: uid %d is not unique\n",
				Prog, (int) user_id);
			exit(E_UID_IN_USE);
		}
		if (! uflg && pwd->pw_uid >= user_id) {
			if (pwd->pw_uid > uid_max)
				continue;
			user_id = pwd->pw_uid + 1;
		}
	}
	/*
	 * If a user with uid equal to UID_MAX exists, the above algorithm
	 * will give us UID_MAX+1 even if not unique.  Search for the first
	 * free uid starting with UID_MIN (it's O(n*n) but can be avoided
	 * by not having users with uid equal to UID_MAX).  --marekm
	 */
	if (!uflg && user_id == uid_max + 1) {
		for (user_id = uid_min; user_id < uid_max; user_id++) {
#ifdef NO_GETPWENT
			pw_rewind();
			while ((pwd = pw_next()) && pwd->pw_uid != user_id)
				;
			if (!pwd)
				break;
#else
			if (!getpwuid(user_id))
				break;
#endif
		}
		if (user_id == uid_max) {
			fprintf(stderr, "%s: can't get unique uid\n",
				Prog);
			fail_exit(E_UID_IN_USE);
		}
	}
}

#ifdef AUTH_METHODS
/*
 * convert_auth - convert the argument list to a authentication list
 */

static void
convert_auth(char *auths, const char *list)
{
	char	*cp, *end;
	char	buf[257];

	/*
	 * Copy each method.  DEFAULT is replaced by an encrypted string
	 * if one can be found in the current authentication list.
	 */

	strcpy(buf, list);
	auths[0] = '\0';
	for (cp = buf; cp; cp = end) {
		if (auths[0])
			strcat(auths, ";");

		if ((end = strchr(cp, ',')))
			*end++ = '\0';

		if (strcmp(cp, "DEFAULT") == 0) {
			strcat(auths, user_pass);
		} else {
			strcat(auths, "@");
			strcat(auths, cp);
		}
	}
}

/*
 * valid_auth - check authentication list for validity
 */

static int
valid_auth(const char *methods)
{
	char	*cp, *end;
	char	buf[257];
	int	default_cnt = 0;

	/*
	 * Cursory checks, length and illegal characters
	 */

	if ((int) strlen (methods) > 256)
		return 0;

	if (! VALID (methods))
		return 0;

	/*
	 * Pick each method apart and check it.
	 */

	strcpy (buf, methods);
	for (cp = buf;cp;cp = end) {
		if ((end = strchr (cp, ',')))
			*end++ = '\0';

		if (strcmp (cp, "DEFAULT") == 0) {
			if (default_cnt++ > 0)
				return 0;
		}
	}
	return 1;
}
#endif  /* AUTH_METHODS */

/*
 * process_flags - perform command line argument setting
 *
 *	process_flags() interprets the command line arguments and sets
 *	the values that the user will be created with accordingly.  The
 *	values are checked for sanity.
 */

static void
process_flags(int argc, char **argv)
{
	const struct group *grp;
	int anyflag = 0;
	int arg;
	char *cp;

#ifdef SHADOWPWD
#define FLAGS "A:Du:og:G:d:s:c:mk:p:f:e:b:O:"
#else
#define FLAGS "A:Du:og:G:d:s:c:mk:p:b:O:"
#endif
	while ((arg = getopt(argc, argv, FLAGS)) != EOF) {
#undef FLAGS
		switch (arg) {
#ifdef AUTH_METHODS
		case 'A':
			if (! valid_auth (optarg)) {
				fprintf(stderr,
					"%s: invalid field `%s'\n",
					Prog, optarg);
				exit(E_BAD_ARG);
			}
			auth_arg = optarg;
			Aflg++;
			break;
#endif
		case 'b':
			if (!Dflg)
				usage ();

			if (!VALID(optarg) || optarg[0] != '/') {
				fprintf(stderr,
					"%s: invalid base directory `%s'\n",
					Prog, optarg);
				exit(E_BAD_ARG);
			}
			def_home = optarg;
			bflg++;
			break;
		case 'c':
			if (!VALID(optarg)) {
				fprintf(stderr,
					"%s: invalid comment `%s'\n",
					Prog, optarg);
				exit(E_BAD_ARG);
			}
			user_comment = optarg;
			cflg++;
			break;
		case 'd':
			if (!VALID(optarg) || optarg[0] != '/') {
				fprintf(stderr,
					"%s: invalid home directory `%s'\n",
					Prog, optarg);
				exit(E_BAD_ARG);
			}
			user_home = optarg;
			dflg++;
			break;
		case 'D':
			if (anyflag)
				usage();
			Dflg++;
			break;
#ifdef SHADOWPWD
		case 'e':
			if (*optarg) {
				user_expire = strtoday(optarg);
				if (user_expire == -1) {
					fprintf(stderr,
						"%s: invalid date `%s'\n",
						Prog, optarg);
					exit(E_BAD_ARG);
				}
			} else
				user_expire = -1;

			/*
			 * -e "" is allowed - it's a no-op without /etc/shadow
			 */
			if (*optarg && !is_shadow_pwd) {
				fprintf(stderr,
					"%s: shadow passwords required for -e\n",
					Prog);
				exit(E_USAGE);
			}
			if (Dflg)
				def_expire = optarg;
			eflg++;
			break;
		case 'f':
			def_inactive = get_number(optarg);
			/*
			 * -f -1 is allowed - it's a no-op without /etc/shadow
			 */
			if (def_inactive != -1 && !is_shadow_pwd) {
				fprintf(stderr,
					"%s: shadow passwords required for -f\n",
					Prog);
				exit(E_USAGE);
			}
			fflg++;
			break;
#endif
		case 'g':
			grp = getgr_nam_gid(optarg);
			if (!grp) {
				fprintf(stderr, "%s: unknown group %s\n",
					Prog, optarg);
				exit(E_NOTFOUND);
			}
			if (Dflg) {
				def_group = grp->gr_gid;
				def_gname = optarg;
			} else {
				user_gid = grp->gr_gid;
			}
			gflg++;
			break;
		case 'G':
			if (get_groups(optarg))
				exit(E_NOTFOUND);
			if (user_groups[0])
				do_grp_update++;
			Gflg++;
			break;
		case 'k':
			def_template = optarg;
			kflg++;
			break;
		case 'm':
			mflg++;
			break;
		case 'o':
			oflg++;
			break;
		case 'O':
			/*
			 * override login.defs defaults (-O name=value)
			 * example: -O UID_MIN=100 -O UID_MAX=499
			 * note: -O UID_MIN=10,UID_MAX=499 doesn't work yet
			 */
			cp = strchr(optarg, '=');
			if (!cp) {
				fprintf(stderr,
					"%s: -O requires NAME=VALUE\n",
					Prog);
				exit(E_BAD_ARG);
			}
			/* terminate name, point to value */
			*cp++ = '\0';
			if (putdef_str(optarg, cp) < 0)
				exit(E_BAD_ARG);
			break;
		case 'p':  /* set encrypted password */
			if (!VALID(optarg)) {
				fprintf(stderr, "%s: invalid field `%s'\n",
					Prog, optarg);
				exit(E_BAD_ARG);
			}
			user_pass = optarg;
			break;
		case 's':
			if (!VALID(optarg) || (optarg[0] &&
			    (optarg[0] != '/' && optarg[0] != '*'))) {
				fprintf(stderr, "%s: invalid shell `%s'\n",
					Prog, optarg);
				exit(E_BAD_ARG);
			}
			user_shell = optarg;
			def_shell = optarg;
			sflg++;
			break;
		case 'u':
			user_id = get_number(optarg);
			uflg++;
			break;
		default:
			usage();
		}
		anyflag++;
	}

	/*
	 * Certain options are only valid in combination with others.
	 * Check it here so that they can be specified in any order.
	 */
	if ((oflg && !uflg) || (kflg && !mflg))
		usage();

	/*
	 * Either -D or username is required.  Defaults can be set with -D
	 * for the -b, -e, -f, -g, -s options only.
	 */
	if (Dflg) {
		if (optind != argc)
			usage();

		if (uflg || oflg || Gflg || dflg || cflg || mflg)
			usage();
	} else {
		if (optind != argc - 1)
			usage();

		user_name = argv[optind];
		if (!check_user_name(user_name)) {
			fprintf(stderr, "%s: invalid user name `%s'\n",
				Prog, user_name);
			exit(E_BAD_ARG);
		}
		if (!dflg) {
			user_home = xmalloc(strlen(def_home) + strlen(user_name) + 2);
			sprintf(user_home, "%s/%s", def_home, user_name);
		}
	}

#ifdef SHADOWPWD
	if (!eflg)
		user_expire = strtoday(def_expire);
#endif

	if (!gflg)
		user_gid = def_group;

	if (!sflg)
		user_shell = def_shell;
}

/*
 * close_files - close all of the files that were opened
 *
 *	close_files() closes all of the files that were opened for this
 *	new user.  This causes any modified entries to be written out.
 */

static void
close_files(void)
{
	if (!pw_close()) {
		fprintf(stderr, "%s: cannot rewrite password file\n", Prog);
		fail_exit(E_PW_UPDATE);
	}
#ifdef	SHADOWPWD
	if (is_shadow_pwd && !spw_close()) {
		fprintf(stderr, "%s: cannot rewrite shadow password file\n",	
			Prog);
		fail_exit(E_PW_UPDATE);
	}
#endif
	if (do_grp_update) {
		if (!gr_close()) {
			fprintf(stderr, "%s: cannot rewrite group file\n",
				Prog);
			fail_exit(E_GRP_UPDATE);
		}
		gr_unlock();
#ifdef	SHADOWGRP
		if (is_shadow_grp && !sgr_close()) {
			fprintf (stderr, "%s: cannot rewrite shadow group file\n",
				Prog);
			fail_exit(E_GRP_UPDATE);
		}
		if (is_shadow_grp)
			sgr_unlock();
#endif
	}
#ifdef	SHADOWPWD
	if (is_shadow_pwd)
		spw_unlock();
#endif
	pw_unlock();
}

/*
 * open_files - lock and open the password files
 *
 *	open_files() opens the two password files.
 */

static void
open_files(void)
{
	if (!pw_lock()) {
		fprintf(stderr, "%s: unable to lock password file\n", Prog);
		exit(E_PW_UPDATE);
	}
	if (!pw_open(O_RDWR)) {
		fprintf(stderr, "%s: unable to open password file\n", Prog);
		pw_unlock();
		exit(E_PW_UPDATE);
	}
#ifdef	SHADOWPWD
	if (is_shadow_pwd && !spw_lock()) {
		fprintf(stderr, "%s: cannot lock shadow password file\n", Prog);
		pw_unlock();
		exit(E_PW_UPDATE);
	}
	if (is_shadow_pwd && !spw_open(O_RDWR)) {
		fprintf(stderr, "%s: cannot open shadow password file\n", Prog);
		spw_unlock();
		pw_unlock();
		exit(E_PW_UPDATE);
	}
#endif
}


static void
faillog_reset(uid_t uid)
{
	struct faillog fl;
	int fd;

	fd = open(FAILLOG_FILE, O_RDWR);
	if (fd >= 0) {
		memzero(&fl, sizeof(fl));
		lseek(fd, (off_t) sizeof(fl) * uid, SEEK_SET);
		write(fd, &fl, sizeof(fl));
		close(fd);
	}
}

static void
lastlog_reset(uid_t uid)
{
	struct lastlog ll;
	int fd;

	fd = open(LASTLOG_FILE, O_RDWR);
	if (fd >= 0) {
		memzero(&ll, sizeof(ll));
		lseek(fd, (off_t) sizeof(ll) * uid, SEEK_SET);
		write(fd, &ll, sizeof(ll));
		close(fd);
	}
}

/*
 * usr_update - create the user entries
 *
 *	usr_update() creates the password file entries for this user
 *	and will update the group entries if required.
 */

static void
usr_update(void)
{
	struct	passwd	pwent;
#ifdef	SHADOWPWD
	struct	spwd	spent;
#endif

	if (! oflg)
		find_new_uid ();

#ifdef AUTH_METHODS
	if (Aflg) {
		convert_auth(user_auth, auth_arg);
		user_pass = user_auth;
	}
#endif

	/*
	 * Fill in the password structure with any new fields, making
	 * copies of strings.
	 */

	new_pwent (&pwent);
#ifdef	SHADOWPWD
	new_spent (&spent);
#endif

	/*
	 * Create a syslog entry.  We need to do this now in case anything
	 * happens so we know what we were trying to accomplish.
	 */

#ifdef AUTH_METHODS
	SYSLOG((LOG_INFO,
	    "new user: name=%s, uid=%d, gid=%d, home=%s, shell=%s, auth=%s\n",
		user_name, user_id, user_gid, user_home, user_shell,
		Aflg ? auth_arg : "DEFAULT"));
#else
	SYSLOG((LOG_INFO,
		"new user: name=%s, uid=%d, gid=%d, home=%s, shell=%s\n",
		user_name, user_id, user_gid, user_home, user_shell));
#endif

#ifdef AUTH_METHODS
	/*
	 * Attempt to add the new user to any authentication programs
	 * which have been requested.  Since this is more likely to fail
	 * than the update of the password file, we do this first.
	 */

	if (Aflg && pw_auth(user_auth, pwent.pw_name, PW_ADD, (char *) 0)) {
		fprintf(stderr, "%s: error adding authentication method\n",
			Prog);
		fail_exit(E_PW_UPDATE);  /* XXX */
	}
#endif  /* AUTH_METHODS */

	/*
	 * Initialize faillog and lastlog entries for this UID in case
	 * it belongs to a previously deleted user.  We do it only if
	 * no user with this UID exists yet (entries for shared UIDs
	 * are left unchanged).  --marekm
	 */

	if (!getpwuid(user_id)) {
		faillog_reset(user_id);
		lastlog_reset(user_id);
	}

	/*
	 * Put the new (struct passwd) in the table.
	 */

	if (! pw_update (&pwent)) {
		fprintf(stderr, "%s: error adding new password entry\n", Prog);
		exit(E_PW_UPDATE);
	}

#ifdef NDBM
	/*
	 * Update the DBM files.  This creates the user before the flat
	 * files are updated.  This is safe before the password field is
	 * either locked, or set to a valid authentication string.
	 */

	if (pw_dbm_present()) {
		if (!pw_dbm_update(&pwent)) {
			fprintf(stderr,
				"%s: error updating password dbm entry\n",
				Prog);
			exit(E_PW_UPDATE);
		} else
			pw_dbm_added = 1;
	}
	endpwent();
#endif

#ifdef	SHADOWPWD
	/*
	 * Put the new (struct spwd) in the table.
	 */

	if (is_shadow_pwd && !spw_update(&spent)) {
		fprintf(stderr, "%s: error adding new shadow password entry\n",
			Prog);
		exit(E_PW_UPDATE);
	}

#ifdef	NDBM
	/* 
	 * Update the DBM files for the shadow password.  This entry is
	 * output before the entry in the flat file, but this is safe as
	 * the password is locked or the authentication string has the
	 * proper values.
	 */

	if (is_shadow_pwd && sp_dbm_present()) {
		if (!sp_dbm_update(&spent)) {
			fprintf(stderr,
				"%s: error updating shadow passwd dbm entry\n",
				Prog);
			fail_exit(E_PW_UPDATE);
		} else
			sp_dbm_added++;
		endspent();
	}
#endif
#endif	/* SHADOWPWD */

	/*
	 * Do any group file updates for this user.
	 */

	if (do_grp_update)
		grp_update();
}

/*
 * create_home - create the user's home directory
 *
 *	create_home() creates the user's home directory if it does not
 *	already exist.  It will be created mode 755 owned by the user
 *	with the user's default group.
 */

static void
create_home(void)
{
	if (access(user_home, F_OK)) {
		/* XXX - create missing parent directories.  --marekm */
		if (mkdir (user_home, 0)) {
			fprintf(stderr, "%s: cannot create directory %s\n",
				Prog, user_home);
			fail_exit(E_HOMEDIR);
		}
		chown (user_home, user_id, user_gid);
#if 1
		chmod(user_home, 0777 & ~getdef_num("UMASK", 077));
#else
		chmod (user_home, 0755);
#endif
		home_added++;
	}
}

/*
 * main - useradd command
 */

int
main(int argc, char **argv)
{
	/*
	 * Get my name so that I can use it to report errors.
	 */

	Prog = Basename(argv[0]);

	openlog(Prog, LOG_PID|LOG_CONS|LOG_NOWAIT, LOG_AUTH);

#ifdef SHADOWPWD
	is_shadow_pwd = spw_file_present();
#endif
#ifdef SHADOWGRP
	is_shadow_grp = sgr_file_present();
#endif

	/*
	 * The open routines for the NDBM files don't use read-write
	 * as the mode, so we have to clue them in.
	 */

#ifdef	NDBM
	pw_dbm_mode = O_RDWR;
#ifdef	SHADOWPWD
	sp_dbm_mode = O_RDWR;
#endif
	gr_dbm_mode = O_RDWR;
#ifdef	SHADOWGRP
	sg_dbm_mode = O_RDWR;
#endif
#endif
	get_defaults();

	process_flags(argc, argv);

	/*
	 * See if we are messing with the defaults file, or creating
	 * a new user.
	 */

	if (Dflg) {
		if (gflg || bflg || fflg || eflg || sflg)
			exit (set_defaults () ? 1:0);

		show_defaults();
		exit(E_SUCCESS);
	}

	/*
	 * Start with a quick check to see if the user exists.
	 */

	if (getpwnam(user_name)) {
		fprintf(stderr, "%s: user %s exists\n", Prog, user_name);
		exit(E_NAME_IN_USE);
	}

	/*
	 * Do the hard stuff - open the files, create the user entries,
	 * create the home directory, then close and update the files.
	 */

	open_files ();

	usr_update ();

	if (mflg) {
		create_home ();
		copy_tree (def_template, user_home, user_id, user_gid);
	}
	close_files ();
	exit(E_SUCCESS);
	/*NOTREACHED*/
}
