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kern_prot.c revision 1.105 
      1 /*	$NetBSD: kern_prot.c,v 1.105 2007/12/20 23:03:08 dsl Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1982, 1986, 1989, 1990, 1991, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  * (c) UNIX System Laboratories, Inc.
      7  * All or some portions of this file are derived from material licensed
      8  * to the University of California by American Telephone and Telegraph
      9  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
     10  * the permission of UNIX System Laboratories, Inc.
     11  *
     12  * Redistribution and use in source and binary forms, with or without
     13  * modification, are permitted provided that the following conditions
     14  * are met:
     15  * 1. Redistributions of source code must retain the above copyright
     16  *    notice, this list of conditions and the following disclaimer.
     17  * 2. Redistributions in binary form must reproduce the above copyright
     18  *    notice, this list of conditions and the following disclaimer in the
     19  *    documentation and/or other materials provided with the distribution.
     20  * 3. Neither the name of the University nor the names of its contributors
     21  *    may be used to endorse or promote products derived from this software
     22  *    without specific prior written permission.
     23  *
     24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     34  * SUCH DAMAGE.
     35  *
     36  *	@(#)kern_prot.c	8.9 (Berkeley) 2/14/95
     37  */
     38 
     39 /*
     40  * System calls related to processes and protection
     41  */
     42 
     43 #include <sys/cdefs.h>
     44 __KERNEL_RCSID(0, "$NetBSD: kern_prot.c,v 1.105 2007/12/20 23:03:08 dsl Exp $");
     45 
     46 #include "opt_compat_43.h"
     47 
     48 #include <sys/param.h>
     49 #include <sys/acct.h>
     50 #include <sys/systm.h>
     51 #include <sys/ucred.h>
     52 #include <sys/proc.h>
     53 #include <sys/timeb.h>
     54 #include <sys/times.h>
     55 #include <sys/pool.h>
     56 #include <sys/prot.h>
     57 #include <sys/syslog.h>
     58 #include <sys/resourcevar.h>
     59 #include <sys/kauth.h>
     60 
     61 #include <sys/mount.h>
     62 #include <sys/syscallargs.h>
     63 
     64 int	sys_getpid(struct lwp *, const void *, register_t *);
     65 int	sys_getpid_with_ppid(struct lwp *, const void *, register_t *);
     66 int	sys_getuid(struct lwp *, const void *, register_t *);
     67 int	sys_getuid_with_euid(struct lwp *, const void *, register_t *);
     68 int	sys_getgid(struct lwp *, const void *, register_t *);
     69 int	sys_getgid_with_egid(struct lwp *, const void *, register_t *);
     70 
     71 /* ARGSUSED */
     72 int
     73 sys_getpid(struct lwp *l, const void *v, register_t *retval)
     74 {
     75 	struct proc *p = l->l_proc;
     76 
     77 	*retval = p->p_pid;
     78 	return (0);
     79 }
     80 
     81 /* ARGSUSED */
     82 int
     83 sys_getpid_with_ppid(struct lwp *l, const void *v, register_t *retval)
     84 {
     85 	struct proc *p = l->l_proc;
     86 
     87 	retval[0] = p->p_pid;
     88 	mutex_enter(&proclist_lock);
     89 	retval[1] = p->p_pptr->p_pid;
     90 	mutex_exit(&proclist_lock);
     91 	return (0);
     92 }
     93 
     94 /* ARGSUSED */
     95 int
     96 sys_getppid(struct lwp *l, const void *v, register_t *retval)
     97 {
     98 	struct proc *p = l->l_proc;
     99 
    100 	mutex_enter(&proclist_lock);
    101 	*retval = p->p_pptr->p_pid;
    102 	mutex_exit(&proclist_lock);
    103 	return (0);
    104 }
    105 
    106 /* Get process group ID; note that POSIX getpgrp takes no parameter */
    107 int
    108 sys_getpgrp(struct lwp *l, const void *v, register_t *retval)
    109 {
    110 	struct proc *p = l->l_proc;
    111 
    112 	mutex_enter(&proclist_lock);
    113 	*retval = p->p_pgrp->pg_id;
    114 	mutex_exit(&proclist_lock);
    115 	return (0);
    116 }
    117 
    118 /*
    119  * Return the process group ID of the session leader (session ID)
    120  * for the specified process.
    121  */
    122 int
    123 sys_getsid(struct lwp *l, const struct sys_getsid_args *uap, register_t *retval)
    124 {
    125 	/* {
    126 		syscalldarg(pid_t) pid;
    127 	} */
    128 	pid_t pid = SCARG(uap, pid);
    129 	struct proc *p;
    130 	int error = 0;
    131 
    132 	mutex_enter(&proclist_lock);
    133 	if (pid == 0)
    134 		*retval = l->l_proc->p_session->s_sid;
    135 	else if ((p = p_find(pid, PFIND_LOCKED)) != NULL)
    136 		*retval = p->p_session->s_sid;
    137 	else
    138 		error = ESRCH;
    139 	mutex_exit(&proclist_lock);
    140 
    141 	return error;
    142 }
    143 
    144 int
    145 sys_getpgid(struct lwp *l, const struct sys_getpgid_args *uap, register_t *retval)
    146 {
    147 	/* {
    148 		syscallarg(pid_t) pid;
    149 	} */
    150 	pid_t pid = SCARG(uap, pid);
    151 	struct proc *p;
    152 	int error = 0;
    153 
    154 	mutex_enter(&proclist_lock);
    155 	if (pid == 0)
    156 		*retval = l->l_proc->p_pgid;
    157 	else if ((p = p_find(pid, PFIND_LOCKED)) != NULL)
    158 		*retval = p->p_pgid;
    159 	else
    160 		error = ESRCH;
    161 	mutex_exit(&proclist_lock);
    162 
    163 	return error;
    164 }
    165 
    166 /* ARGSUSED */
    167 int
    168 sys_getuid(struct lwp *l, const void *v, register_t *retval)
    169 {
    170 
    171 	*retval = kauth_cred_getuid(l->l_cred);
    172 	return (0);
    173 }
    174 
    175 /* ARGSUSED */
    176 int
    177 sys_getuid_with_euid(struct lwp *l, const void *v, register_t *retval)
    178 {
    179 
    180 	retval[0] = kauth_cred_getuid(l->l_cred);
    181 	retval[1] = kauth_cred_geteuid(l->l_cred);
    182 	return (0);
    183 }
    184 
    185 /* ARGSUSED */
    186 int
    187 sys_geteuid(struct lwp *l, const void *v, register_t *retval)
    188 {
    189 
    190 	*retval = kauth_cred_geteuid(l->l_cred);
    191 	return (0);
    192 }
    193 
    194 /* ARGSUSED */
    195 int
    196 sys_getgid(struct lwp *l, const void *v, register_t *retval)
    197 {
    198 
    199 	*retval = kauth_cred_getgid(l->l_cred);
    200 	return (0);
    201 }
    202 
    203 /* ARGSUSED */
    204 int
    205 sys_getgid_with_egid(struct lwp *l, const void *v, register_t *retval)
    206 {
    207 
    208 	retval[0] = kauth_cred_getgid(l->l_cred);
    209 	retval[1] = kauth_cred_getegid(l->l_cred);
    210 	return (0);
    211 }
    212 
    213 /*
    214  * Get effective group ID.  The "egid" is groups[0], and could be obtained
    215  * via getgroups.  This syscall exists because it is somewhat painful to do
    216  * correctly in a library function.
    217  */
    218 /* ARGSUSED */
    219 int
    220 sys_getegid(struct lwp *l, const void *v, register_t *retval)
    221 {
    222 
    223 	*retval = kauth_cred_getegid(l->l_cred);
    224 	return (0);
    225 }
    226 
    227 int
    228 sys_getgroups(struct lwp *l, const struct sys_getgroups_args *uap, register_t *retval)
    229 {
    230 	/* {
    231 		syscallarg(int) gidsetsize;
    232 		syscallarg(gid_t *) gidset;
    233 	} */
    234 
    235 	*retval = kauth_cred_ngroups(l->l_cred);
    236 	if (SCARG(uap, gidsetsize) == 0)
    237 		return 0;
    238 	if (SCARG(uap, gidsetsize) < *retval)
    239 		return EINVAL;
    240 
    241 	return kauth_cred_getgroups(l->l_cred, SCARG(uap, gidset), *retval,
    242 	    UIO_USERSPACE);
    243 }
    244 
    245 /* ARGSUSED */
    246 int
    247 sys_setsid(struct lwp *l, const void *v, register_t *retval)
    248 {
    249 	struct proc *p = l->l_proc;
    250 	int error;
    251 
    252 	error = enterpgrp(p, p->p_pid, p->p_pid, 1);
    253 	*retval = p->p_pid;
    254 	return (error);
    255 }
    256 
    257 
    258 /*
    259  * set process group (setpgid/old setpgrp)
    260  *
    261  * caller does setpgid(targpid, targpgid)
    262  *
    263  * pgid must be in valid range (EINVAL)
    264  * pid must be caller or child of caller (ESRCH)
    265  * if a child
    266  *	pid must be in same session (EPERM)
    267  *	pid can't have done an exec (EACCES)
    268  * if pgid != pid
    269  * 	there must exist some pid in same session having pgid (EPERM)
    270  * pid must not be session leader (EPERM)
    271  *
    272  * Permission checks now in enterpgrp()
    273  */
    274 /* ARGSUSED */
    275 int
    276 sys_setpgid(struct lwp *l, const struct sys_setpgid_args *uap, register_t *retval)
    277 {
    278 	/* {
    279 		syscallarg(int) pid;
    280 		syscallarg(int) pgid;
    281 	} */
    282 	struct proc *p = l->l_proc;
    283 	pid_t targp, pgid;
    284 
    285 	if (SCARG(uap, pgid) < 0)
    286 		return EINVAL;
    287 	if ((targp = SCARG(uap, pid)) == 0)
    288 		targp = p->p_pid;
    289 	if ((pgid = SCARG(uap, pgid)) == 0)
    290 		pgid = targp;
    291 
    292 	return enterpgrp(p, targp, pgid, 0);
    293 }
    294 
    295 /*
    296  * Set real, effective and saved uids to the requested values.
    297  * non-root callers can only ever change uids to values that match
    298  * one of the processes current uid values.
    299  * This is further restricted by the flags argument.
    300  */
    301 
    302 int
    303 do_setresuid(struct lwp *l, uid_t r, uid_t e, uid_t sv, u_int flags)
    304 {
    305 	struct proc *p = l->l_proc;
    306 	kauth_cred_t cred, ncred;
    307 
    308 	ncred = kauth_cred_alloc();
    309 
    310 	/* Get a write lock on the process credential. */
    311 	proc_crmod_enter();
    312 	cred = p->p_cred;
    313 
    314 	/*
    315 	 * Check that the new value is one of the allowed existing values,
    316 	 * or that we have root privilege.
    317 	 */
    318 	if ((r != -1
    319 	    && !((flags & ID_R_EQ_R) && r == kauth_cred_getuid(cred))
    320 	    && !((flags & ID_R_EQ_E) && r == kauth_cred_geteuid(cred))
    321 	    && !((flags & ID_R_EQ_S) && r == kauth_cred_getsvuid(cred))) ||
    322 	    (e != -1
    323 	    && !((flags & ID_E_EQ_R) && e == kauth_cred_getuid(cred))
    324 	    && !((flags & ID_E_EQ_E) && e == kauth_cred_geteuid(cred))
    325 	    && !((flags & ID_E_EQ_S) && e == kauth_cred_getsvuid(cred))) ||
    326 	    (sv != -1
    327 	    && !((flags & ID_S_EQ_R) && sv == kauth_cred_getuid(cred))
    328 	    && !((flags & ID_S_EQ_E) && sv == kauth_cred_geteuid(cred))
    329 	    && !((flags & ID_S_EQ_S) && sv == kauth_cred_getsvuid(cred)))) {
    330 		int error;
    331 
    332 		error = kauth_authorize_process(cred, KAUTH_PROCESS_SETID,
    333 		    p, NULL, NULL, NULL);
    334 		if (error != 0) {
    335 		 	proc_crmod_leave(cred, ncred, false);
    336 			return error;
    337 		}
    338 	}
    339 
    340 	/* If nothing has changed, short circuit the request */
    341 	if ((r == -1 || r == kauth_cred_getuid(cred))
    342 	    && (e == -1 || e == kauth_cred_geteuid(cred))
    343 	    && (sv == -1 || sv == kauth_cred_getsvuid(cred))) {
    344 		proc_crmod_leave(cred, ncred, false);
    345 		return 0;
    346 	}
    347 
    348 	kauth_cred_clone(cred, ncred);
    349 
    350 	if (r != -1 && r != kauth_cred_getuid(ncred)) {
    351 		/* Update count of processes for this user */
    352 		(void)chgproccnt(kauth_cred_getuid(ncred), -1);
    353 		(void)chgproccnt(r, 1);
    354 		kauth_cred_setuid(ncred, r);
    355 	}
    356 	if (sv != -1)
    357 		kauth_cred_setsvuid(ncred, sv);
    358 	if (e != -1)
    359 		kauth_cred_seteuid(ncred, e);
    360 
    361 	/* Broadcast our credentials to the process and other LWPs. */
    362  	proc_crmod_leave(ncred, cred, true);
    363 
    364 	return 0;
    365 }
    366 
    367 /*
    368  * Set real, effective and saved gids to the requested values.
    369  * non-root callers can only ever change gids to values that match
    370  * one of the processes current gid values.
    371  * This is further restricted by the flags argument.
    372  */
    373 
    374 int
    375 do_setresgid(struct lwp *l, gid_t r, gid_t e, gid_t sv, u_int flags)
    376 {
    377 	struct proc *p = l->l_proc;
    378 	kauth_cred_t cred, ncred;
    379 
    380 	ncred = kauth_cred_alloc();
    381 
    382 	/* Get a write lock on the process credential. */
    383 	proc_crmod_enter();
    384 	cred = p->p_cred;
    385 
    386 	/*
    387 	 * check new value is one of the allowed existing values.
    388 	 * otherwise, check if we have root privilege.
    389 	 */
    390 	if ((r != -1
    391 	    && !((flags & ID_R_EQ_R) && r == kauth_cred_getgid(cred))
    392 	    && !((flags & ID_R_EQ_E) && r == kauth_cred_getegid(cred))
    393 	    && !((flags & ID_R_EQ_S) && r == kauth_cred_getsvgid(cred))) ||
    394 	    (e != -1
    395 	    && !((flags & ID_E_EQ_R) && e == kauth_cred_getgid(cred))
    396 	    && !((flags & ID_E_EQ_E) && e == kauth_cred_getegid(cred))
    397 	    && !((flags & ID_E_EQ_S) && e == kauth_cred_getsvgid(cred))) ||
    398 	    (sv != -1
    399 	    && !((flags & ID_S_EQ_R) && sv == kauth_cred_getgid(cred))
    400 	    && !((flags & ID_S_EQ_E) && sv == kauth_cred_getegid(cred))
    401 	    && !((flags & ID_S_EQ_S) && sv == kauth_cred_getsvgid(cred)))) {
    402 		int error;
    403 
    404 		error = kauth_authorize_process(cred, KAUTH_PROCESS_SETID,
    405 		    p, NULL, NULL, NULL);
    406 		if (error != 0) {
    407 		 	proc_crmod_leave(cred, ncred, false);
    408 			return error;
    409 		}
    410 	}
    411 
    412 	/* If nothing has changed, short circuit the request */
    413 	if ((r == -1 || r == kauth_cred_getgid(cred))
    414 	    && (e == -1 || e == kauth_cred_getegid(cred))
    415 	    && (sv == -1 || sv == kauth_cred_getsvgid(cred))) {
    416 	 	proc_crmod_leave(cred, ncred, false);
    417 		return 0;
    418 	}
    419 
    420 	kauth_cred_clone(cred, ncred);
    421 
    422 	if (r != -1)
    423 		kauth_cred_setgid(ncred, r);
    424 	if (sv != -1)
    425 		kauth_cred_setsvgid(ncred, sv);
    426 	if (e != -1)
    427 		kauth_cred_setegid(ncred, e);
    428 
    429 	/* Broadcast our credentials to the process and other LWPs. */
    430  	proc_crmod_leave(ncred, cred, true);
    431 
    432 	return 0;
    433 }
    434 
    435 /* ARGSUSED */
    436 int
    437 sys_setuid(struct lwp *l, const struct sys_setuid_args *uap, register_t *retval)
    438 {
    439 	/* {
    440 		syscallarg(uid_t) uid;
    441 	} */
    442 	uid_t uid = SCARG(uap, uid);
    443 
    444 	return do_setresuid(l, uid, uid, uid,
    445 			    ID_R_EQ_R | ID_E_EQ_R | ID_S_EQ_R);
    446 }
    447 
    448 /* ARGSUSED */
    449 int
    450 sys_seteuid(struct lwp *l, const struct sys_seteuid_args *uap, register_t *retval)
    451 {
    452 	/* {
    453 		syscallarg(uid_t) euid;
    454 	} */
    455 
    456 	return do_setresuid(l, -1, SCARG(uap, euid), -1, ID_E_EQ_R | ID_E_EQ_S);
    457 }
    458 
    459 int
    460 sys_setreuid(struct lwp *l, const struct sys_setreuid_args *uap, register_t *retval)
    461 {
    462 	/* {
    463 		syscallarg(uid_t) ruid;
    464 		syscallarg(uid_t) euid;
    465 	} */
    466 	kauth_cred_t cred = l->l_cred;
    467 	uid_t ruid, euid, svuid;
    468 
    469 	ruid = SCARG(uap, ruid);
    470 	euid = SCARG(uap, euid);
    471 
    472 	if (ruid == -1)
    473 		ruid = kauth_cred_getuid(cred);
    474 	if (euid == -1)
    475 		euid = kauth_cred_geteuid(cred);
    476 
    477 	/* Saved uid is set to the new euid if the ruid changed */
    478 	svuid = (ruid == kauth_cred_getuid(cred)) ? -1 : euid;
    479 
    480 	return do_setresuid(l, ruid, euid, svuid,
    481 			    ID_R_EQ_R | ID_R_EQ_E |
    482 			    ID_E_EQ_R | ID_E_EQ_E | ID_E_EQ_S |
    483 			    ID_S_EQ_R | ID_S_EQ_E | ID_S_EQ_S);
    484 }
    485 
    486 /* ARGSUSED */
    487 int
    488 sys_setgid(struct lwp *l, const struct sys_setgid_args *uap, register_t *retval)
    489 {
    490 	/* {
    491 		syscallarg(gid_t) gid;
    492 	} */
    493 	gid_t gid = SCARG(uap, gid);
    494 
    495 	return do_setresgid(l, gid, gid, gid,
    496 			    ID_R_EQ_R | ID_E_EQ_R | ID_S_EQ_R);
    497 }
    498 
    499 /* ARGSUSED */
    500 int
    501 sys_setegid(struct lwp *l, const struct sys_setegid_args *uap, register_t *retval)
    502 {
    503 	/* {
    504 		syscallarg(gid_t) egid;
    505 	} */
    506 
    507 	return do_setresgid(l, -1, SCARG(uap, egid), -1, ID_E_EQ_R | ID_E_EQ_S);
    508 }
    509 
    510 int
    511 sys_setregid(struct lwp *l, const struct sys_setregid_args *uap, register_t *retval)
    512 {
    513 	/* {
    514 		syscallarg(gid_t) rgid;
    515 		syscallarg(gid_t) egid;
    516 	} */
    517 	kauth_cred_t cred = l->l_cred;
    518 	gid_t rgid, egid, svgid;
    519 
    520 	rgid = SCARG(uap, rgid);
    521 	egid = SCARG(uap, egid);
    522 
    523 	if (rgid == -1)
    524 		rgid = kauth_cred_getgid(cred);
    525 	if (egid == -1)
    526 		egid = kauth_cred_getegid(cred);
    527 
    528 	/* Saved gid is set to the new egid if the rgid changed */
    529 	svgid = rgid == kauth_cred_getgid(cred) ? -1 : egid;
    530 
    531 	return do_setresgid(l, rgid, egid, svgid,
    532 			ID_R_EQ_R | ID_R_EQ_E |
    533 			ID_E_EQ_R | ID_E_EQ_E | ID_E_EQ_S |
    534 			ID_S_EQ_R | ID_S_EQ_E | ID_S_EQ_S);
    535 }
    536 
    537 int
    538 sys_issetugid(struct lwp *l, const void *v, register_t *retval)
    539 {
    540 	struct proc *p = l->l_proc;
    541 
    542 	/*
    543 	 * Note: OpenBSD sets a P_SUGIDEXEC flag set at execve() time,
    544 	 * we use PK_SUGID because we consider changing the owners as
    545 	 * "tainting" as well.
    546 	 * This is significant for procs that start as root and "become"
    547 	 * a user without an exec - programs cannot know *everything*
    548 	 * that libc *might* have put in their data segment.
    549 	 */
    550 	*retval = (p->p_flag & PK_SUGID) != 0;
    551 	return (0);
    552 }
    553 
    554 /* ARGSUSED */
    555 int
    556 sys_setgroups(struct lwp *l, const struct sys_setgroups_args *uap, register_t *retval)
    557 {
    558 	/* {
    559 		syscallarg(int) gidsetsize;
    560 		syscallarg(const gid_t *) gidset;
    561 	} */
    562 	kauth_cred_t ncred;
    563 	int error;
    564 
    565 	ncred = kauth_cred_alloc();
    566 	error = kauth_cred_setgroups(ncred, SCARG(uap, gidset),
    567 	    SCARG(uap, gidsetsize), -1, UIO_USERSPACE);
    568 	if (error != 0) {
    569 		kauth_cred_free(ncred);
    570 		return error;
    571 	}
    572 
    573 	return kauth_proc_setgroups(l, ncred);
    574 }
    575 
    576 /*
    577  * Get login name, if available.
    578  */
    579 /* ARGSUSED */
    580 int
    581 sys___getlogin(struct lwp *l, const struct sys___getlogin_args *uap, register_t *retval)
    582 {
    583 	/* {
    584 		syscallarg(char *) namebuf;
    585 		syscallarg(size_t) namelen;
    586 	} */
    587 	struct proc *p = l->l_proc;
    588 	char login[sizeof(p->p_session->s_login)];
    589 	int namelen = SCARG(uap, namelen);
    590 
    591 	if (namelen > sizeof(login))
    592 		namelen = sizeof(login);
    593 	mutex_enter(&proclist_lock);
    594 	memcpy(login, p->p_session->s_login, namelen);
    595 	mutex_exit(&proclist_lock);
    596 	return (copyout(login, (void *)SCARG(uap, namebuf), namelen));
    597 }
    598 
    599 /*
    600  * Set login name.
    601  */
    602 /* ARGSUSED */
    603 int
    604 sys___setlogin(struct lwp *l, const struct sys___setlogin_args *uap, register_t *retval)
    605 {
    606 	/* {
    607 		syscallarg(const char *) namebuf;
    608 	} */
    609 	struct proc *p = l->l_proc;
    610 	struct session *sp;
    611 	char newname[sizeof sp->s_login + 1];
    612 	int error;
    613 
    614 	if ((error = kauth_authorize_process(l->l_cred, KAUTH_PROCESS_SETID,
    615 	    p, NULL, NULL, NULL)) != 0)
    616 		return (error);
    617 	error = copyinstr(SCARG(uap, namebuf), &newname, sizeof newname, NULL);
    618 	if (error != 0)
    619 		return (error == ENAMETOOLONG ? EINVAL : error);
    620 
    621 	mutex_enter(&proclist_lock);
    622 	sp = p->p_session;
    623 	if (sp->s_flags & S_LOGIN_SET && p->p_pid != sp->s_sid &&
    624 	    strncmp(newname, sp->s_login, sizeof sp->s_login) != 0)
    625 		log(LOG_WARNING, "%s (pid %d) changing logname from "
    626 		    "%.*s to %s\n", p->p_comm, p->p_pid,
    627 		    (int)sizeof sp->s_login, sp->s_login, newname);
    628 	sp->s_flags |= S_LOGIN_SET;
    629 	strncpy(sp->s_login, newname, sizeof sp->s_login);
    630 	mutex_exit(&proclist_lock);
    631 	return (0);
    632 }
    633 
    634