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      1 /*	$NetBSD: kern_sig_16.c,v 1.10 2024/12/10 10:52:05 mlelstv Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2006, 2007, 2008 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Andrew Doran.
      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  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 /*
     33  * Copyright (c) 1982, 1986, 1989, 1991, 1993
     34  *	The Regents of the University of California.  All rights reserved.
     35  * (c) UNIX System Laboratories, Inc.
     36  * All or some portions of this file are derived from material licensed
     37  * to the University of California by American Telephone and Telegraph
     38  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
     39  * the permission of UNIX System Laboratories, Inc.
     40  *
     41  * Redistribution and use in source and binary forms, with or without
     42  * modification, are permitted provided that the following conditions
     43  * are met:
     44  * 1. Redistributions of source code must retain the above copyright
     45  *    notice, this list of conditions and the following disclaimer.
     46  * 2. Redistributions in binary form must reproduce the above copyright
     47  *    notice, this list of conditions and the following disclaimer in the
     48  *    documentation and/or other materials provided with the distribution.
     49  * 3. Neither the name of the University nor the names of its contributors
     50  *    may be used to endorse or promote products derived from this software
     51  *    without specific prior written permission.
     52  *
     53  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     54  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     55  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     56  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     57  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     58  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     59  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     60  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     61  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     62  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     63  * SUCH DAMAGE.
     64  *
     65  *	@(#)kern_sig.c	8.14 (Berkeley) 5/14/95
     66  */
     67 
     68 #include <sys/cdefs.h>
     69 __KERNEL_RCSID(0, "$NetBSD: kern_sig_16.c,v 1.10 2024/12/10 10:52:05 mlelstv Exp $");
     70 
     71 #if defined(_KERNEL_OPT)
     72 #include "opt_compat_netbsd.h"
     73 #endif
     74 
     75 #include <sys/param.h>
     76 #include <sys/exec.h>
     77 #include <sys/kernel.h>
     78 #include <sys/rwlock.h>
     79 #include <sys/signalvar.h>
     80 #include <sys/proc.h>
     81 #include <sys/pool.h>
     82 #include <sys/syscall.h>
     83 #include <sys/syscallvar.h>
     84 #include <sys/syscallargs.h>
     85 #include <sys/kauth.h>
     86 #include <sys/wait.h>
     87 #include <sys/kmem.h>
     88 #include <sys/compat_stub.h>
     89 
     90 #include <uvm/uvm_object.h>
     91 #include <uvm/uvm_prot.h>
     92 #include <uvm/uvm_pager.h>
     93 
     94 #include <compat/common/compat_mod.h>
     95 
     96 #ifdef COMPAT_NETBSD32
     97 # ifndef __aarch64__
     98 #  define COMPAT_SIGCONTEXT
     99 # endif
    100 #else /* COMPAT_NETBSD32 */
    101 # if !defined(__amd64__) && !defined(__aarch64__)
    102 #  define COMPAT_SIGCONTEXT
    103 # endif
    104 #endif /* COMPAT_NETBSD32 */
    105 
    106 #ifdef COMPAT_SIGCONTEXT
    107 extern char sigcode[], esigcode[];
    108 struct uvm_object *emul_netbsd_object;
    109 #endif
    110 
    111 static const struct syscall_package kern_sig_16_syscalls[] = {
    112 #ifdef COMPAT_SIGCONTEXT
    113 	{ SYS_compat_16___sigaction14, 0,
    114 	    (sy_call_t *)compat_16_sys___sigaction14 },
    115 	/* compat_16_sigreturn14 is in MD code! */
    116 	{ SYS_compat_16___sigreturn14, 0,
    117 	    (sy_call_t *)compat_16_sys___sigreturn14 },
    118 #endif
    119 	{ 0, 0, NULL }
    120 };
    121 
    122 int
    123 compat_16_sys___sigaction14(struct lwp *l,
    124     const struct compat_16_sys___sigaction14_args *uap, register_t *retval)
    125 {
    126 	/* {
    127 		syscallarg(int)				signum;
    128 		syscallarg(const struct sigaction *)	nsa;
    129 		syscallarg(struct sigaction *)		osa;
    130 	} */
    131 	struct sigaction	nsa, osa;
    132 	int			error;
    133 
    134 	if (SCARG(uap, nsa)) {
    135 		error = copyin(SCARG(uap, nsa), &nsa, sizeof(nsa));
    136 		if (error)
    137 			return (error);
    138 	}
    139 	error = sigaction1(l, SCARG(uap, signum),
    140 	    SCARG(uap, nsa) ? &nsa : 0, SCARG(uap, osa) ? &osa : 0,
    141 	    NULL, 0);
    142 	if (error)
    143 		return (error);
    144 	if (SCARG(uap, osa)) {
    145 		error = copyout(&osa, SCARG(uap, osa), sizeof(osa));
    146 		if (error)
    147 			return (error);
    148 	}
    149 	return (0);
    150 }
    151 
    152 int
    153 kern_sig_16_init(void)
    154 {
    155 	int error;
    156 
    157 	error = syscall_establish(NULL, kern_sig_16_syscalls);
    158 	if (error)
    159 		return error;
    160 #if defined(COMPAT_SIGCONTEXT)
    161 	KASSERT(emul_netbsd.e_sigobject == NULL);
    162 	rw_enter(&exec_lock, RW_WRITER);
    163 	emul_netbsd.e_sigcode = sigcode;
    164 	emul_netbsd.e_esigcode = esigcode;
    165 	emul_netbsd.e_sigobject = &emul_netbsd_object;
    166 	error = exec_sigcode_alloc(&emul_netbsd);
    167 	if (error) {
    168 		emul_netbsd.e_sigcode = NULL;
    169 		emul_netbsd.e_esigcode = NULL;
    170 		emul_netbsd.e_sigobject = NULL;
    171 	}
    172 	rw_exit(&exec_lock);
    173 	if (error)
    174 		return error;
    175 	MODULE_HOOK_SET(sendsig_sigcontext_16_hook, sendsig_sigcontext);
    176 #endif
    177 
    178 	return 0;
    179 }
    180 
    181 int
    182 kern_sig_16_fini(void)
    183 {
    184 	proc_t *p;
    185 	int error;
    186 
    187 	error = syscall_disestablish(NULL, kern_sig_16_syscalls);
    188 	if (error)
    189 		return error;
    190 	/*
    191 	 * Ensure sendsig_sigcontext() is not being used.
    192 	 * module_lock prevents the flag being set on any
    193 	 * further processes while we are here.  See
    194 	 * sigaction1() for the opposing half.
    195 	 */
    196 	mutex_enter(&proc_lock);
    197 	PROCLIST_FOREACH(p, &allproc) {
    198 		if ((p->p_lflag & PL_SIGCOMPAT) != 0) {
    199 			break;
    200 		}
    201 	}
    202 	mutex_exit(&proc_lock);
    203 	if (p != NULL) {
    204 		syscall_establish(NULL, kern_sig_16_syscalls);
    205 		return EBUSY;
    206 	}
    207 
    208 #if defined(COMPAT_SIGCONTEXT)
    209 	/*
    210 	 * The sigobject may persist if still in use, but
    211 	 * is reference counted so will die eventually.
    212 	 */
    213 	rw_enter(&exec_lock, RW_WRITER);
    214 	exec_sigcode_free(&emul_netbsd);
    215 	emul_netbsd_object = NULL;
    216 	emul_netbsd.e_sigcode = NULL;
    217 	emul_netbsd.e_esigcode = NULL;
    218 	emul_netbsd.e_sigobject = NULL;
    219 	rw_exit(&exec_lock);
    220 
    221 	MODULE_HOOK_UNSET(sendsig_sigcontext_16_hook);
    222 #endif
    223 	return 0;
    224 }
    225 
    226