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utmpx.c revision 1.24 
      1 /*	$NetBSD: utmpx.c,v 1.24 2006/11/26 17:33:23 christos Exp $	 */
      2 
      3 /*-
      4  * Copyright (c) 2002 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Christos Zoulas.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *        This product includes software developed by the NetBSD
     21  *        Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 #include <sys/cdefs.h>
     39 
     40 #if defined(LIBC_SCCS) && !defined(lint)
     41 __RCSID("$NetBSD: utmpx.c,v 1.24 2006/11/26 17:33:23 christos Exp $");
     42 #endif /* LIBC_SCCS and not lint */
     43 
     44 #include "namespace.h"
     45 #include <sys/types.h>
     46 #include <sys/param.h>
     47 #include <sys/socket.h>
     48 #include <sys/stat.h>
     49 #include <sys/time.h>
     50 #include <sys/wait.h>
     51 
     52 #include <assert.h>
     53 #include <db.h>
     54 #include <errno.h>
     55 #include <fcntl.h>
     56 #include <stdio.h>
     57 #include <stdlib.h>
     58 #include <string.h>
     59 #include <unistd.h>
     60 #include <utmp.h>
     61 #include <utmpx.h>
     62 #include <vis.h>
     63 
     64 static FILE *fp;
     65 static int readonly = 0;
     66 static struct utmpx ut;
     67 static char utfile[MAXPATHLEN] = _PATH_UTMPX;
     68 
     69 static struct utmpx *utmp_update(const struct utmpx *);
     70 
     71 static const char vers[] = "utmpx-1.00";
     72 
     73 void
     74 setutxent()
     75 {
     76 
     77 	(void)memset(&ut, 0, sizeof(ut));
     78 	if (fp == NULL)
     79 		return;
     80 	(void)fseeko(fp, (off_t)sizeof(ut), SEEK_SET);
     81 }
     82 
     83 
     84 void
     85 endutxent()
     86 {
     87 
     88 	(void)memset(&ut, 0, sizeof(ut));
     89 	if (fp != NULL) {
     90 		(void)fclose(fp);
     91 		fp = NULL;
     92 		readonly = 0;
     93 	}
     94 }
     95 
     96 
     97 struct utmpx *
     98 getutxent()
     99 {
    100 
    101 	if (fp == NULL) {
    102 		struct stat st;
    103 
    104 		if ((fp = fopen(utfile, "r+")) == NULL)
    105 			if ((fp = fopen(utfile, "w+")) == NULL) {
    106 				if ((fp = fopen(utfile, "r")) == NULL)
    107 					goto fail;
    108 				else
    109 					readonly = 1;
    110 			}
    111 
    112 
    113 		/* get file size in order to check if new file */
    114 		if (fstat(fileno(fp), &st) == -1)
    115 			goto failclose;
    116 
    117 		if (st.st_size == 0) {
    118 			/* new file, add signature record */
    119 			(void)memset(&ut, 0, sizeof(ut));
    120 			ut.ut_type = SIGNATURE;
    121 			(void)memcpy(ut.ut_user, vers, sizeof(vers));
    122 			if (fwrite(&ut, sizeof(ut), 1, fp) != 1)
    123 				goto failclose;
    124 		} else {
    125 			/* old file, read signature record */
    126 			if (fread(&ut, sizeof(ut), 1, fp) != 1)
    127 				goto failclose;
    128 			if (memcmp(ut.ut_user, vers, sizeof(vers)) != 0 ||
    129 			    ut.ut_type != SIGNATURE)
    130 				goto failclose;
    131 		}
    132 	}
    133 
    134 	if (fread(&ut, sizeof(ut), 1, fp) != 1)
    135 		goto fail;
    136 
    137 	return &ut;
    138 failclose:
    139 	(void)fclose(fp);
    140 fail:
    141 	(void)memset(&ut, 0, sizeof(ut));
    142 	return NULL;
    143 }
    144 
    145 
    146 struct utmpx *
    147 getutxid(const struct utmpx *utx)
    148 {
    149 
    150 	_DIAGASSERT(utx != NULL);
    151 
    152 	if (utx->ut_type == EMPTY)
    153 		return NULL;
    154 
    155 	do {
    156 		if (ut.ut_type == EMPTY)
    157 			continue;
    158 		switch (utx->ut_type) {
    159 		case EMPTY:
    160 			return NULL;
    161 		case RUN_LVL:
    162 		case BOOT_TIME:
    163 		case OLD_TIME:
    164 		case NEW_TIME:
    165 			if (ut.ut_type == utx->ut_type)
    166 				return &ut;
    167 			break;
    168 		case INIT_PROCESS:
    169 		case LOGIN_PROCESS:
    170 		case USER_PROCESS:
    171 		case DEAD_PROCESS:
    172 			switch (ut.ut_type) {
    173 			case INIT_PROCESS:
    174 			case LOGIN_PROCESS:
    175 			case USER_PROCESS:
    176 			case DEAD_PROCESS:
    177 				if (memcmp(ut.ut_id, utx->ut_id,
    178 				    sizeof(ut.ut_id)) == 0)
    179 					return &ut;
    180 				break;
    181 			default:
    182 				break;
    183 			}
    184 			break;
    185 		default:
    186 			return NULL;
    187 		}
    188 	} while (getutxent() != NULL);
    189 	return NULL;
    190 }
    191 
    192 
    193 struct utmpx *
    194 getutxline(const struct utmpx *utx)
    195 {
    196 
    197 	_DIAGASSERT(utx != NULL);
    198 
    199 	do {
    200 		switch (ut.ut_type) {
    201 		case EMPTY:
    202 			break;
    203 		case LOGIN_PROCESS:
    204 		case USER_PROCESS:
    205 			if (strncmp(ut.ut_line, utx->ut_line,
    206 			    sizeof(ut.ut_line)) == 0)
    207 				return &ut;
    208 			break;
    209 		default:
    210 			break;
    211 		}
    212 	} while (getutxent() != NULL);
    213 	return NULL;
    214 }
    215 
    216 
    217 struct utmpx *
    218 pututxline(const struct utmpx *utx)
    219 {
    220 	struct utmpx temp, *u = NULL;
    221 	int gotlock = 0;
    222 
    223 	_DIAGASSERT(utx != NULL);
    224 
    225 	if (utx == NULL)
    226 		return NULL;
    227 
    228 	if (strcmp(_PATH_UTMPX, utfile) == 0)
    229 		if ((fp != NULL && readonly) || (fp == NULL && geteuid() != 0))
    230 			return utmp_update(utx);
    231 
    232 
    233 	(void)memcpy(&temp, utx, sizeof(temp));
    234 
    235 	if (fp == NULL) {
    236 		(void)getutxent();
    237 		if (fp == NULL || readonly)
    238 			return NULL;
    239 	}
    240 
    241 	if (getutxid(&temp) == NULL) {
    242 		setutxent();
    243 		if (getutxid(&temp) == NULL) {
    244 			if (lockf(fileno(fp), F_LOCK, (off_t)0) == -1)
    245 				return NULL;
    246 			gotlock++;
    247 			if (fseeko(fp, (off_t)0, SEEK_END) == -1)
    248 				goto fail;
    249 		}
    250 	}
    251 
    252 	if (!gotlock) {
    253 		/* we are not appending */
    254 		if (fseeko(fp, -(off_t)sizeof(ut), SEEK_CUR) == -1)
    255 			return NULL;
    256 	}
    257 
    258 	if (fwrite(&temp, sizeof (temp), 1, fp) != 1)
    259 		goto fail;
    260 
    261 	if (fflush(fp) == -1)
    262 		goto fail;
    263 
    264 	u = memcpy(&ut, &temp, sizeof(ut));
    265 fail:
    266 	if (gotlock) {
    267 		if (lockf(fileno(fp), F_ULOCK, (off_t)0) == -1)
    268 			return NULL;
    269 	}
    270 	return u;
    271 }
    272 
    273 
    274 static struct utmpx *
    275 utmp_update(const struct utmpx *utx)
    276 {
    277 	char buf[sizeof(*utx) * 4 + 1];
    278 	pid_t pid;
    279 	int status;
    280 
    281 	_DIAGASSERT(utx != NULL);
    282 
    283 	(void)strvisx(buf, (const char *)(const void *)utx, sizeof(*utx),
    284 	    VIS_WHITE);
    285 	switch (pid = fork()) {
    286 	case 0:
    287 		(void)execl(_PATH_UTMP_UPDATE,
    288 		    strrchr(_PATH_UTMP_UPDATE, '/') + 1, buf, NULL);
    289 		_exit(1);
    290 		/*NOTREACHED*/
    291 	case -1:
    292 		return NULL;
    293 	default:
    294 		if (waitpid(pid, &status, 0) == -1)
    295 			return NULL;
    296 		if (WIFEXITED(status) && WEXITSTATUS(status) == 0)
    297 			return memcpy(&ut, utx, sizeof(ut));
    298 		return NULL;
    299 	}
    300 
    301 }
    302 
    303 /*
    304  * The following are extensions and not part of the X/Open spec.
    305  */
    306 int
    307 updwtmpx(const char *file, const struct utmpx *utx)
    308 {
    309 	int fd;
    310 	int saved_errno;
    311 
    312 	_DIAGASSERT(file != NULL);
    313 	_DIAGASSERT(utx != NULL);
    314 
    315 	fd = open(file, O_WRONLY|O_APPEND|O_SHLOCK);
    316 
    317 	if (fd == -1) {
    318 		if ((fd = open(file, O_CREAT|O_WRONLY|O_EXLOCK, 0644)) == -1)
    319 			return -1;
    320 		(void)memset(&ut, 0, sizeof(ut));
    321 		ut.ut_type = SIGNATURE;
    322 		(void)memcpy(ut.ut_user, vers, sizeof(vers));
    323 		if (write(fd, &ut, sizeof(ut)) == -1)
    324 			goto failed;
    325 	}
    326 	if (write(fd, utx, sizeof(*utx)) == -1)
    327 		goto failed;
    328 	if (close(fd) == -1)
    329 		return -1;
    330 	return 0;
    331 
    332   failed:
    333 	saved_errno = errno;
    334 	(void) close(fd);
    335 	errno = saved_errno;
    336 	return -1;
    337 }
    338 
    339 
    340 int
    341 utmpxname(const char *fname)
    342 {
    343 	size_t len;
    344 
    345 	_DIAGASSERT(fname != NULL);
    346 
    347 	len = strlen(fname);
    348 
    349 	if (len >= sizeof(utfile))
    350 		return 0;
    351 
    352 	/* must end in x! */
    353 	if (fname[len - 1] != 'x')
    354 		return 0;
    355 
    356 	(void)strlcpy(utfile, fname, sizeof(utfile));
    357 	endutxent();
    358 	return 1;
    359 }
    360 
    361 
    362 void
    363 getutmp(const struct utmpx *ux, struct utmp *u)
    364 {
    365 
    366 	_DIAGASSERT(ux != NULL);
    367 	_DIAGASSERT(u != NULL);
    368 
    369 	(void)memcpy(u->ut_name, ux->ut_name, sizeof(u->ut_name));
    370 	(void)memcpy(u->ut_line, ux->ut_line, sizeof(u->ut_line));
    371 	(void)memcpy(u->ut_host, ux->ut_host, sizeof(u->ut_host));
    372 	u->ut_time = ux->ut_tv.tv_sec;
    373 }
    374 
    375 void
    376 getutmpx(const struct utmp *u, struct utmpx *ux)
    377 {
    378 
    379 	_DIAGASSERT(ux != NULL);
    380 	_DIAGASSERT(u != NULL);
    381 
    382 	(void)memcpy(ux->ut_name, u->ut_name, sizeof(u->ut_name));
    383 	(void)memcpy(ux->ut_line, u->ut_line, sizeof(u->ut_line));
    384 	(void)memcpy(ux->ut_host, u->ut_host, sizeof(u->ut_host));
    385 	ux->ut_tv.tv_sec = u->ut_time;
    386 	ux->ut_tv.tv_usec = 0;
    387 	(void)memset(&ux->ut_ss, 0, sizeof(ux->ut_ss));
    388 	ux->ut_pid = 0;
    389 	ux->ut_type = USER_PROCESS;
    390 	ux->ut_session = 0;
    391 	ux->ut_exit.e_termination = 0;
    392 	ux->ut_exit.e_exit = 0;
    393 }
    394 
    395 struct lastlogx *
    396 getlastlogx(const char *fname, uid_t uid, struct lastlogx *ll)
    397 {
    398 	DBT key, data;
    399 	DB *db;
    400 
    401 	_DIAGASSERT(fname != NULL);
    402 	_DIAGASSERT(ll != NULL);
    403 
    404 	db = dbopen(fname, O_RDONLY|O_SHLOCK, 0, DB_HASH, NULL);
    405 
    406 	if (db == NULL)
    407 		return NULL;
    408 
    409 	key.data = &uid;
    410 	key.size = sizeof(uid);
    411 
    412 	if ((db->get)(db, &key, &data, 0) != 0)
    413 		goto error;
    414 
    415 	if (data.size != sizeof(*ll)) {
    416 		errno = EFTYPE;
    417 		goto error;
    418 	}
    419 
    420 	if (ll == NULL)
    421 		if ((ll = malloc(sizeof(*ll))) == NULL)
    422 			goto done;
    423 
    424 	(void)memcpy(ll, data.data, sizeof(*ll));
    425 	goto done;
    426 error:
    427 	ll = NULL;
    428 done:
    429 	(db->close)(db);
    430 	return ll;
    431 }
    432 
    433 int
    434 updlastlogx(const char *fname, uid_t uid, struct lastlogx *ll)
    435 {
    436 	DBT key, data;
    437 	int error = 0;
    438 	DB *db;
    439 
    440 	_DIAGASSERT(fname != NULL);
    441 	_DIAGASSERT(ll != NULL);
    442 
    443 	db = dbopen(fname, O_RDWR|O_CREAT|O_EXLOCK, 0644, DB_HASH, NULL);
    444 
    445 	if (db == NULL)
    446 		return -1;
    447 
    448 	key.data = &uid;
    449 	key.size = sizeof(uid);
    450 	data.data = ll;
    451 	data.size = sizeof(*ll);
    452 	if ((db->put)(db, &key, &data, 0) != 0)
    453 		error = -1;
    454 
    455 	(db->close)(db);
    456 	return error;
    457 }
    458