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utmpx.c revision 1.6 
      1 /*	$NetBSD: utmpx.c,v 1.6 2002/04/15 16:47:03 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 1.6 2002/04/15 16:47:03 christos Exp $");
     42 #endif /* LIBC_SCCS and not lint */
     43 
     44 #include <sys/types.h>
     45 #include <sys/param.h>
     46 #include <sys/wait.h>
     47 #include <sys/socket.h>
     48 #include <sys/time.h>
     49 #include <sys/stat.h>
     50 
     51 #include <stdio.h>
     52 #include <stdlib.h>
     53 #include <string.h>
     54 #include <vis.h>
     55 #include <utmp.h>
     56 #include <utmpx.h>
     57 #include <unistd.h>
     58 #include <fcntl.h>
     59 
     60 static FILE *fp;
     61 static struct utmpx ut;
     62 static char utfile[MAXPATHLEN] = _PATH_UTMPX;
     63 
     64 static struct utmpx *utmp_update(const struct utmpx *);
     65 
     66 static const char vers[] = "utmpx-1.00";
     67 
     68 void
     69 setutxent()
     70 {
     71 	(void)memset(&ut, 0, sizeof(ut));
     72 	if (fp == NULL)
     73 		return;
     74 	(void)fseeko(fp, (off_t)sizeof(ut), SEEK_SET);
     75 }
     76 
     77 
     78 void
     79 endutxent()
     80 {
     81 	(void)memset(&ut, 0, sizeof(ut));
     82 	if (fp != NULL)
     83 		(void)fclose(fp);
     84 }
     85 
     86 
     87 struct utmpx *
     88 getutxent()
     89 {
     90 	if (fp == NULL) {
     91 		struct stat st;
     92 
     93 		if ((fp = fopen(utfile, "r+")) == NULL)
     94 			if ((fp = fopen(utfile, "w+")) == NULL)
     95 				if ((fp = fopen(utfile, "r")) == NULL)
     96 					goto fail;
     97 
     98 		/* get file size in order to check if new file */
     99 		if (fstat(fileno(fp), &st) == -1)
    100 			goto failclose;
    101 
    102 		if (st.st_size == 0) {
    103 			/* new file, add signature record */
    104 			(void)memset(&ut, 0, sizeof(ut));
    105 			ut.ut_type = SIGNATURE;
    106 			(void)memcpy(ut.ut_user, vers, sizeof(vers));
    107 			if (fwrite(&ut, sizeof(ut), 1, fp) != 1)
    108 				goto failclose;
    109 		} else {
    110 			/* old file, read signature record */
    111 			if (fread(&ut, sizeof(ut), 1, fp) != 1)
    112 				goto failclose;
    113 			if (memcmp(ut.ut_user, vers, sizeof(vers)) != 0 ||
    114 			    ut.ut_type != SIGNATURE)
    115 				goto failclose;
    116 		}
    117 	}
    118 
    119 	if (fread(&ut, sizeof(ut), 1, fp) != 1)
    120 		goto fail;
    121 
    122 	return &ut;
    123 failclose:
    124 	(void)fclose(fp);
    125 fail:
    126 	(void)memset(&ut, 0, sizeof(ut));
    127 	return NULL;
    128 }
    129 
    130 
    131 struct utmpx *
    132 getutxid(const struct utmpx *utx)
    133 {
    134 	if (utx->ut_type == EMPTY)
    135 		return NULL;
    136 
    137 	do {
    138 		if (ut.ut_type == EMPTY)
    139 			continue;
    140 		switch (utx->ut_type) {
    141 		case EMPTY:
    142 			return NULL;
    143 		case RUN_LVL:
    144 		case BOOT_TIME:
    145 		case OLD_TIME:
    146 		case NEW_TIME:
    147 			if (ut.ut_type == utx->ut_type)
    148 				return &ut;
    149 			break;
    150 		case INIT_PROCESS:
    151 		case LOGIN_PROCESS:
    152 		case USER_PROCESS:
    153 		case DEAD_PROCESS:
    154 			switch (ut.ut_type) {
    155 			case INIT_PROCESS:
    156 			case LOGIN_PROCESS:
    157 			case USER_PROCESS:
    158 			case DEAD_PROCESS:
    159 				if (memcmp(ut.ut_id, utx->ut_id,
    160 				    sizeof(ut.ut_id)) == 0)
    161 					return &ut;
    162 				break;
    163 			default:
    164 				break;
    165 			}
    166 			break;
    167 		default:
    168 			return NULL;
    169 		}
    170 	}
    171 	while (getutxent() != NULL);
    172 	return NULL;
    173 }
    174 
    175 
    176 struct utmpx *
    177 getutxline(const struct utmpx *utx)
    178 {
    179 	do {
    180 		switch (ut.ut_type) {
    181 		case EMPTY:
    182 			break;
    183 		case LOGIN_PROCESS:
    184 		case USER_PROCESS:
    185 			if (strncmp(ut.ut_line, utx->ut_line,
    186 			    sizeof(ut.ut_line)) == 0)
    187 				return &ut;
    188 			break;
    189 		default:
    190 			break;
    191 		}
    192 	}
    193 	while (getutxent() != NULL);
    194 	return NULL;
    195 }
    196 
    197 
    198 struct utmpx *
    199 pututxline(const struct utmpx *utx)
    200 {
    201 	struct utmpx temp, *u = NULL;
    202 	int gotlock = 0;
    203 
    204 	if (strcmp(_PATH_UTMPX, utfile) == 0 && geteuid() != 0)
    205 		return utmp_update(utx);
    206 
    207 	if (utx == NULL)
    208 		return NULL;
    209 
    210 	(void)memcpy(&temp, utx, sizeof(temp));
    211 
    212 	if (fp == NULL) {
    213 		(void)getutxent();
    214 		if (fp == NULL)
    215 			return NULL;
    216 	}
    217 
    218 	if (getutxid(&temp) == NULL) {
    219 		setutxent();
    220 		if (getutxid(&temp) == NULL) {
    221 			if (lockf(fileno(fp), F_LOCK, (off_t)0) == -1)
    222 				return NULL;
    223 			gotlock++;
    224 			if (fseeko(fp, (off_t)0, SEEK_END) == -1)
    225 				goto fail;
    226 		}
    227 	}
    228 
    229 	if (!gotlock) {
    230 		/* we are not appending */
    231 		if (fseeko(fp, -(off_t)sizeof(ut), SEEK_CUR) == -1)
    232 			return NULL;
    233 	}
    234 
    235 	if (fwrite(&temp, sizeof (temp), 1, fp) != 1)
    236 		goto fail;
    237 
    238 	if (fflush(fp) == -1)
    239 		goto fail;
    240 
    241 	u = memcpy(&ut, &temp, sizeof(ut));
    242 fail:
    243 	if (gotlock) {
    244 		if (lockf(fileno(fp), F_ULOCK, (off_t)0) == -1)
    245 			return NULL;
    246 	}
    247 	return u;
    248 }
    249 
    250 
    251 static struct utmpx *
    252 utmp_update(const struct utmpx *utx)
    253 {
    254 	char buf[sizeof(*utx) * 4 + 1];
    255 	pid_t pid;
    256 	int status;
    257 
    258 	(void)strvisx(buf, (const char *)(const void *)utx, sizeof(*utx),
    259 	    VIS_WHITE);
    260 	switch (pid = fork()) {
    261 	case 0:
    262 		(void)execl(_PATH_UTMP_UPDATE,
    263 		    strrchr(_PATH_UTMP_UPDATE, '/') + 1, buf);
    264 		exit(1);
    265 		/*NOTREACHED*/
    266 	case -1:
    267 		return NULL;
    268 	default:
    269 		if (waitpid(pid, &status, 0) == -1)
    270 			return NULL;
    271 		if (WIFEXITED(status) && WEXITSTATUS(status) == 0)
    272 			return memcpy(&ut, utx, sizeof(ut));
    273 		return NULL;
    274 	}
    275 
    276 }
    277 
    278 void
    279 updwtmpx(const char *file, const struct utmpx *utx)
    280 {
    281 	int fd = open(file, O_WRONLY | O_APPEND);
    282 	if (fd == -1) {
    283 		if ((fd = open(file, O_CREAT | O_WRONLY, 0644)) == -1)
    284 			return;
    285 		(void)memset(&ut, 0, sizeof(ut));
    286 		ut.ut_type = SIGNATURE;
    287 		(void)memcpy(ut.ut_user, vers, sizeof(vers));
    288 		(void)write(fd, &ut, sizeof(ut));
    289 	}
    290 	(void)write(fd, utx, sizeof(*utx));
    291 	(void)close(fd);
    292 }
    293 
    294 
    295 /*
    296  * The following are extensions and not part of the X/Open spec
    297  */
    298 int
    299 utmpxname(const char *fname)
    300 {
    301 	size_t len = strlen(fname);
    302 
    303 	if (len >= sizeof(utfile))
    304 		return 0;
    305 
    306 	/* must end in x! */
    307 	if (fname[len - 1] != 'x')
    308 		return 0;
    309 
    310 	(void)strcpy(utfile, fname);
    311 	endutxent();
    312 	return 1;
    313 }
    314 
    315 
    316 void
    317 getutmp(const struct utmpx *ux, struct utmp *u)
    318 {
    319 	(void)memcpy(u->ut_name, ux->ut_name, sizeof(u->ut_name));
    320 	(void)memcpy(u->ut_line, ux->ut_line, sizeof(u->ut_line));
    321 	(void)memcpy(u->ut_host, ux->ut_host, sizeof(u->ut_host));
    322 	u->ut_time = ux->ut_tv.tv_sec;
    323 }
    324 
    325 void
    326 getutmpx(const struct utmp *u, struct utmpx *ux)
    327 {
    328 	(void)memcpy(ux->ut_name, u->ut_name, sizeof(u->ut_name));
    329 	(void)memcpy(ux->ut_line, u->ut_line, sizeof(u->ut_line));
    330 	(void)memcpy(ux->ut_host, u->ut_host, sizeof(u->ut_host));
    331 	ux->ut_tv.tv_sec = u->ut_time;
    332 	ux->ut_tv.tv_usec = 0;
    333 	(void)memset(&ux->ut_ss, 0, sizeof(ux->ut_ss));
    334 	ux->ut_pid = 0;
    335 	ux->ut_type = USER_PROCESS;
    336 	ux->ut_session = 0;
    337 	ux->ut_exit.e_termination = 0;
    338 	ux->ut_exit.e_exit = 0;
    339 }
    340