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      1 /*	$NetBSD: netbsd32_rlimit.c,v 1.2 2021/01/19 03:20:13 simonb Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1998, 2001, 2008, 2018 Matthew R. Green
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     22  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  *
     28  * from: NetBSD: netbsd32_netbsd.c,v 1.218 2018/08/10 21:44:58 pgoyette Exp
     29  */
     30 
     31 /* rlimit netbsd32 related code */
     32 
     33 #include <sys/cdefs.h>
     34 __KERNEL_RCSID(0, "$NetBSD: netbsd32_rlimit.c,v 1.2 2021/01/19 03:20:13 simonb Exp $");
     35 
     36 #include <sys/param.h>
     37 #include <sys/systm.h>
     38 #include <sys/resource.h>
     39 #include <sys/exec.h>
     40 
     41 #include <compat/netbsd32/netbsd32.h>
     42 #include <compat/netbsd32/netbsd32_syscall.h>
     43 #include <compat/netbsd32/netbsd32_syscallargs.h>
     44 #include <compat/netbsd32/netbsd32_conv.h>
     45 
     46 #define LIMITCHECK(a, b) ((a) != RLIM_INFINITY && (a) > (b))
     47 
     48 static void
     49 fixlimit(int which, struct rlimit *alim)
     50 {
     51 	switch (which) {
     52 	case RLIMIT_DATA:
     53 		if (LIMITCHECK(alim->rlim_cur, MAXDSIZ32))
     54 			alim->rlim_cur = MAXDSIZ32;
     55 		if (LIMITCHECK(alim->rlim_max, MAXDSIZ32))
     56 			alim->rlim_max = MAXDSIZ32;
     57 		return;
     58 	case RLIMIT_STACK:
     59 		if (LIMITCHECK(alim->rlim_cur, MAXSSIZ32))
     60 			alim->rlim_cur = MAXSSIZ32;
     61 		if (LIMITCHECK(alim->rlim_max, MAXSSIZ32))
     62 			alim->rlim_max = MAXSSIZ32;
     63 		return;
     64 	default:
     65 		return;
     66 	}
     67 }
     68 
     69 int
     70 netbsd32_getrlimit(struct lwp *l, const struct netbsd32_getrlimit_args *uap,
     71     register_t *retval)
     72 {
     73 	/* {
     74 		syscallarg(int) which;
     75 		syscallarg(netbsd32_rlimitp_t) rlp;
     76 	} */
     77 	int which = SCARG(uap, which);
     78 	struct rlimit alim;
     79 
     80 	if ((u_int)which >= RLIM_NLIMITS)
     81 		return EINVAL;
     82 
     83 	alim = l->l_proc->p_rlimit[which];
     84 
     85 	fixlimit(which, &alim);
     86 
     87 	return copyout(&alim, SCARG_P32(uap, rlp), sizeof(alim));
     88 }
     89 
     90 int
     91 netbsd32_setrlimit(struct lwp *l, const struct netbsd32_setrlimit_args *uap,
     92     register_t *retval)
     93 {
     94 	/* {
     95 		syscallarg(int) which;
     96 		syscallarg(const netbsd32_rlimitp_t) rlp;
     97 	} */
     98 		int which = SCARG(uap, which);
     99 	struct rlimit alim;
    100 	int error;
    101 
    102 	if ((u_int)which >= RLIM_NLIMITS)
    103 		return EINVAL;
    104 
    105 	error = copyin(SCARG_P32(uap, rlp), &alim, sizeof(struct rlimit));
    106 	if (error)
    107 		return error;
    108 
    109 	fixlimit(which, &alim);
    110 
    111 	return dosetrlimit(l, l->l_proc, which, &alim);
    112 }
    113 
    114 void
    115 netbsd32_adjust_limits(struct proc *p)
    116 {
    117 	static const struct {
    118 		int id;
    119 		rlim_t lim;
    120 	} lm[] = {
    121 		{ RLIMIT_DATA,	MAXDSIZ32 },
    122 		{ RLIMIT_STACK, MAXSSIZ32 },
    123 	};
    124 	size_t i;
    125 	struct plimit *lim;
    126 	struct rlimit *rlim;
    127 
    128 	/*
    129 	 * We can only reduce the current limits, we cannot stop external
    130 	 * processes from changing them (eg via sysctl) later on.
    131 	 * So there is no point trying to lock out such changes here.
    132 	 *
    133 	 * If we assume that rlim_cur/max are accessed using atomic
    134 	 * operations, we don't need to lock against any other updates
    135 	 * that might happen if the plimit structure is shared writable
    136 	 * between multiple processes.
    137 	 */
    138 
    139 	/* Scan to determine is any limits are out of range */
    140 	lim = p->p_limit;
    141 	for (i = 0; ; i++) {
    142 		if (i >= __arraycount(lm))
    143 			/* All in range */
    144 			return;
    145 		rlim = lim->pl_rlimit + lm[i].id;
    146 		if (LIMITCHECK(rlim->rlim_cur, lm[i].lim))
    147 			break;
    148 		if (LIMITCHECK(rlim->rlim_max, lm[i].lim))
    149 			break;
    150 	}
    151 
    152 	lim_privatise(p);
    153 
    154 	lim = p->p_limit;
    155 	for (i = 0; i < __arraycount(lm); i++) {
    156 		rlim = lim->pl_rlimit + lm[i].id;
    157 		if (LIMITCHECK(rlim->rlim_cur, lm[i].lim))
    158 			rlim->rlim_cur = lm[i].lim;
    159 		if (LIMITCHECK(rlim->rlim_max, lm[i].lim))
    160 			rlim->rlim_max = lm[i].lim;
    161 	}
    162 }
    163