/*

 * CDDL HEADER START

 *

 * The contents of this file are subject to the terms of the

 * Common Development and Distribution License (the "License").

 * You may not use this file except in compliance with the License.

 *

 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE

 * or http://www.opensolaris.org/os/licensing.

 * See the License for the specific language governing permissions

 * and limitations under the License.

 *

 * When distributing Covered Code, include this CDDL HEADER in each

 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.

 * If applicable, add the following below this CDDL HEADER, with the

 * fields enclosed by brackets "[]" replaced with your own identifying

 * information: Portions Copyright [yyyy] [name of copyright owner]

 *

 * CDDL HEADER END

 */

/*

 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.

 * Use is subject to license terms.

 */

/*	Copyright (c) 1988 AT&T	*/

/*	  All Rights Reserved  	*/

/*

 * Compatibility routines to read and write alternate

 * utmp-like files.  These routines are only used in

 * the case where utmpname() is used to change to a file

 * other than /var/adm/utmp or /var/adm/wtmp.  In this case,

 * we assume that someone really wants to read old utmp-format

 * files.  Otherwise, the getutent, setutent, getutid, setutline,

 * and pututline functions are actually wrappers around the

 * equivalent function operating on utmpx-like files.

 */

#include "lint.h"

#include <stdio.h>

#include <sys/param.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <utmpx.h>

#include <errno.h>

#include <fcntl.h>

#include <string.h>

#include <strings.h>

#include <stdlib.h>

#include <unistd.h>

#include <ctype.h>

#include <utime.h>

#include <sys/wait.h>

#define	IDLEN	4	/* length of id field in utmp */

#define	SC_WILDC	0xff	/* wild char for utmp ids */

#define	MAXVAL	255	/* max value for an id 'character' */

#ifdef ut_time

#undef ut_time

#endif

static void	utmp_frec2api(const struct futmp *, struct utmp *);

static void	utmp_api2frec(const struct utmp *, struct futmp *);

struct utmp 	*_compat_getutent(void);

struct utmp	*_compat_getutid(const struct utmp *);

struct utmp	*_compat_getutline(const struct utmp *);

struct utmp	*_compat_pututline(const struct utmp *);

void		_compat_setutent(void);

void		_compat_endutent(void);

void		_compat_updwtmp(const char *, struct utmp *);

struct utmp	*_compat_makeut(struct utmp *);

struct utmp	*_compat_modut(struct utmp *);

static void	unlockut(void);

static int	idcmp(const char *, const char *);

static int	allocid(char *, unsigned char *);

static int	lockut(void);

static int fd = -1;	/* File descriptor for the utmp file. */

/*

 * name of the current utmp-like file - set by utmpname (getutx.c)

 * only if running in backward compatibility mode

 * We don't modify this, but we can't declare it const or lint will freak.

 */

extern char _compat_utmpfile[];

#ifdef ERRDEBUG

static long loc_utmp;	/* Where in "utmp" the current "ubuf" was found. */

#endif

static struct futmp fubuf;	/* Copy of last entry read in. */

static struct utmp ubuf;	/* Last entry returned to client */

/*

 * In the 64-bit world, the utmp data structure grows because of

 * the ut_time field (a time_t) at the end of it.

 */

static void

utmp_frec2api(const struct futmp *src, struct utmp *dst)

{

	if (src == NULL)

		return;

	(void) strncpy(dst->ut_user, src->ut_user, sizeof (dst->ut_user));

	(void) strncpy(dst->ut_line, src->ut_line, sizeof (dst->ut_line));

	(void) memcpy(dst->ut_id, src->ut_id, sizeof (dst->ut_id));

	dst->ut_pid = src->ut_pid;

	dst->ut_type = src->ut_type;

	dst->ut_exit.e_termination = src->ut_exit.e_termination;

	dst->ut_exit.e_exit = src->ut_exit.e_exit;

	dst->ut_time = (time_t)src->ut_time;

}

static void

utmp_api2frec(const struct utmp *src, struct futmp *dst)

{

	if (src == NULL)

		return;

	(void) strncpy(dst->ut_user, src->ut_user, sizeof (dst->ut_user));

	(void) strncpy(dst->ut_line, src->ut_line, sizeof (dst->ut_line));

	(void) memcpy(dst->ut_id, src->ut_id, sizeof (dst->ut_id));

	dst->ut_pid = src->ut_pid;

	dst->ut_type = src->ut_type;

	dst->ut_exit.e_termination = src->ut_exit.e_termination;

	dst->ut_exit.e_exit = src->ut_exit.e_exit;

	dst->ut_time = (time32_t)src->ut_time;

}

/*

 * "getutent_frec" gets the raw version of the next entry in the utmp file.

 */

static struct futmp *

getutent_frec(void)

{

	/*

	 * If the "utmp" file is not open, attempt to open it for

	 * reading.  If there is no file, attempt to create one.  If

	 * both attempts fail, return NULL.  If the file exists, but

	 * isn't readable and writeable, do not attempt to create.

	 */

	if (fd < 0) {

		if ((fd = open(_compat_utmpfile, O_RDWR|O_CREAT, 0644)) < 0) {

			/*

			 * If the open failed for permissions, try opening

			 * it only for reading.  All "pututline()" later

			 * will fail the writes.

			 */

			if ((fd = open(_compat_utmpfile, O_RDONLY)) < 0)

				return (NULL);

		}

	}

	/* Try to read in the next entry from the utmp file.  */

	if (read(fd, &fubuf, sizeof (fubuf)) != sizeof (fubuf)) {

		bzero(&fubuf, sizeof (fubuf));

		return (NULL);

	}

	/* Save the location in the file where this entry was found. */

	(void) lseek(fd, 0L, 1);

	return (&fubuf);

}

/*

 * "_compat_getutent" gets the next entry in the utmp file.

 */

struct utmp *

_compat_getutent(void)

{

	struct futmp *futp;

	futp = getutent_frec();

	utmp_frec2api(&fubuf, &ubuf);

	if (futp == NULL)

		return (NULL);

	return (&ubuf);

}

/*

 * "_compat_getutid" finds the specified entry in the utmp file.  If

 * it can't find it, it returns NULL.

 */

struct utmp *

_compat_getutid(const struct utmp *entry)

{

	short type;

	utmp_api2frec(&ubuf, &fubuf);

	/*

	 * Start looking for entry.  Look in our current buffer before

	 * reading in new entries.

	 */

	do {

		/*

		 * If there is no entry in "ubuf", skip to the read.

		 */

		if (fubuf.ut_type != EMPTY) {

			switch (entry->ut_type) {

			/*

			 * Do not look for an entry if the user sent

			 * us an EMPTY entry.

			 */

			case EMPTY:

				return (NULL);

			/*

			 * For RUN_LVL, BOOT_TIME, DOWN_TIME,

			 * OLD_TIME, and NEW_TIME entries, only the

			 * types have to match.  If they do, return

			 * the address of internal buffer.

			 */

			case RUN_LVL:

			case BOOT_TIME:

			case DOWN_TIME:

			case OLD_TIME:

			case NEW_TIME:

				if (entry->ut_type == fubuf.ut_type) {

					utmp_frec2api(&fubuf, &ubuf);

					return (&ubuf);

				}

				break;

			/*

			 * For INIT_PROCESS, LOGIN_PROCESS, USER_PROCESS,

			 * and DEAD_PROCESS the type of the entry in "fubuf",

			 * must be one of the above and id's must match.

			 */

			case INIT_PROCESS:

			case LOGIN_PROCESS:

			case USER_PROCESS:

			case DEAD_PROCESS:

				if (((type = fubuf.ut_type) == INIT_PROCESS ||

				    type == LOGIN_PROCESS ||

				    type == USER_PROCESS ||

				    type == DEAD_PROCESS) &&

				    fubuf.ut_id[0] == entry->ut_id[0] &&

				    fubuf.ut_id[1] == entry->ut_id[1] &&

				    fubuf.ut_id[2] == entry->ut_id[2] &&

				    fubuf.ut_id[3] == entry->ut_id[3]) {

					utmp_frec2api(&fubuf, &ubuf);

					return (&ubuf);

				}

				break;

			/* Do not search for illegal types of entry. */

			default:

				return (NULL);

			}

		}

	} while (getutent_frec() != NULL);

	/* the proper entry wasn't found. */

	utmp_frec2api(&fubuf, &ubuf);

	return (NULL);

}

/*

 * "_compat_getutline" searches the "utmp" file for a LOGIN_PROCESS or

 * USER_PROCESS with the same "line" as the specified "entry".

 */

struct utmp *

_compat_getutline(const struct utmp *entry)

{

	utmp_api2frec(&ubuf, &fubuf);

	do {

		/*

		 * If the current entry is the one we are interested in,

		 * return a pointer to it.

		 */

		if (fubuf.ut_type != EMPTY &&

		    (fubuf.ut_type == LOGIN_PROCESS ||

		    fubuf.ut_type == USER_PROCESS) &&

		    strncmp(&entry->ut_line[0], &fubuf.ut_line[0],

		    sizeof (fubuf.ut_line)) == 0) {

			utmp_frec2api(&fubuf, &ubuf);

			return (&ubuf);

		}

	} while (getutent_frec() != NULL);

	utmp_frec2api(&fubuf, &ubuf);

	return (NULL);

}

/*

 * "_compat_pututline" writes the structure sent into the utmp file

 * If there is already an entry with the same id, then it is

 * overwritten, otherwise a new entry is made at the end of the

 * utmp file.

 */

struct utmp *

_compat_pututline(const struct utmp *entry)

{

	int fc;

	struct utmp *answer;

	struct utmp tmpbuf;

	struct futmp ftmpbuf;

	/*

	 * Copy the user supplied entry into our temporary buffer to

	 * avoid the possibility that the user is actually passing us

	 * the address of "ubuf".

	 */

	tmpbuf = *entry;

	utmp_api2frec(entry, &ftmpbuf);

	(void) getutent_frec();

	if (fd < 0) {

#ifdef	ERRDEBUG

		gdebug("pututline: Unable to create utmp file.\n");

#endif

		return (NULL);

	}

	/* Make sure file is writable */

	if ((fc = fcntl(fd, F_GETFL, NULL)) == -1 || (fc & O_RDWR) != O_RDWR)

		return (NULL);

	/*

	 * Find the proper entry in the utmp file.  Start at the current

	 * location.  If it isn't found from here to the end of the

	 * file, then reset to the beginning of the file and try again.

	 * If it still isn't found, then write a new entry at the end of

	 * the file.  (Making sure the location is an integral number of

	 * utmp structures into the file incase the file is scribbled.)

	 */

	if (_compat_getutid(&tmpbuf) == NULL) {

#ifdef	ERRDEBUG

		gdebug("1st getutid() failed. fd: %d", fd);

#endif

		_compat_setutent();

		if (_compat_getutid(&tmpbuf) == NULL) {

#ifdef	ERRDEBUG

			loc_utmp = lseek(fd, 0L, 1);

			gdebug("2nd getutid() failed. fd: %d loc_utmp: %ld\n",

			    fd, loc_utmp);

#endif

			(void) fcntl(fd, F_SETFL, fc | O_APPEND);

		} else

			(void) lseek(fd, -(long)sizeof (struct futmp), 1);

	} else

		(void) lseek(fd, -(long)sizeof (struct futmp), 1);

	/*

	 * Write out the user supplied structure.  If the write fails,

	 * then the user probably doesn't have permission to write the

	 * utmp file.

	 */

	if (write(fd, &ftmpbuf, sizeof (ftmpbuf)) != sizeof (ftmpbuf)) {

#ifdef	ERRDEBUG

		gdebug("pututline failed: write-%d\n", errno);

#endif

		answer = NULL;

	} else {

		/*

		 * Copy the new user structure into ubuf so that it will

		 * be up to date in the future.

		 */

		fubuf = ftmpbuf;

		utmp_frec2api(&fubuf, &ubuf);

		answer = &ubuf;

#ifdef	ERRDEBUG

		gdebug("id: %c%c loc: %ld\n", fubuf.ut_id[0],

		    fubuf.ut_id[1], fubuf.ut_id[2], fubuf.ut_id[3],

		    loc_utmp);

#endif

	}

	(void) fcntl(fd, F_SETFL, fc);

	return (answer);

}

/*

 * "_compat_setutent" just resets the utmp file back to the beginning.

 */

void

_compat_setutent(void)

{

	if (fd != -1)

		(void) lseek(fd, 0L, 0);

	/*

	 * Zero the stored copy of the last entry read, since we are

	 * resetting to the beginning of the file.

	 */

	bzero(&ubuf, sizeof (ubuf));

	bzero(&fubuf, sizeof (fubuf));

}

/*

 * "_compat_endutent" closes the utmp file.

 */

void

_compat_endutent(void)

{

	if (fd != -1)

		(void) close(fd);

	fd = -1;

	bzero(&ubuf, sizeof (ubuf));

	bzero(&fubuf, sizeof (fubuf));

}

/*

 * If one of wtmp and wtmpx files exist, create the other, and the record.

 * If they both exist add the record.

 */

void

_compat_updwtmp(const char *file, struct utmp *ut)

{

	struct futmp fut;

	int fd;

	fd = open(file, O_WRONLY | O_APPEND);

	if (fd < 0) {

		if ((fd = open(file, O_WRONLY|O_CREAT, 0644)) < 0)

			return;

	}

	(void) lseek(fd, 0, 2);

	utmp_api2frec(ut, &fut);

	(void) write(fd, &fut, sizeof (fut));

	(void) close(fd);

}

/*

 * makeut - create a utmp entry, recycling an id if a wild card is

 *	specified.

 *

 *	args:	utmp - point to utmp structure to be created

 */

struct utmp *

_compat_makeut(struct utmp *utmp)

{

	int i;

	struct utmp *utp;	/* "current" utmp entry being examined */

	int wild;		/* flag, true iff wild card char seen */

	/* the last id we matched that was NOT a dead proc */

	unsigned char saveid[IDLEN];

	wild = 0;

	for (i = 0; i < IDLEN; i++)

		if ((unsigned char)utmp->ut_id[i] == SC_WILDC) {

			wild = 1;

			break;

		}

	if (wild) {

		/*

		 * try to lock the utmp file, only needed if we're

		 * doing wildcard matching

		 */

		if (lockut())

			return (0);

		_compat_setutent();

		/* find the first alphanumeric character */

		for (i = 0; i < MAXVAL; ++i)

			if (isalnum(i))

				break;

		(void) memset(saveid, i, IDLEN);

		while ((utp = _compat_getutent()) != 0) {

			if (idcmp(utmp->ut_id, utp->ut_id))

				continue;

			if (utp->ut_type == DEAD_PROCESS)

				break;

			(void) memcpy(saveid, utp->ut_id, IDLEN);

		}

		if (utp) {

			/*

			 * found an unused entry, reuse it

			 */

			(void) memcpy(utmp->ut_id, utp->ut_id, IDLEN);

			utp = _compat_pututline(utmp);

			if (utp)

				_compat_updwtmp(WTMP_FILE, utp);

			_compat_endutent();

			unlockut();

			return (utp);

		} else {

			/*

			 * nothing available, try to allocate an id

			 */

			if (allocid(utmp->ut_id, saveid)) {

				_compat_endutent();

				unlockut();

				return (NULL);

			} else {

				utp = _compat_pututline(utmp);

				if (utp)

					_compat_updwtmp(WTMP_FILE, utp);

				_compat_endutent();

				unlockut();

				return (utp);

			}

		}

	} else {

		utp = _compat_pututline(utmp);

		if (utp)