xref: /freebsd/sys/compat/linux/linux_sysctl.c (revision 2008043f386721d58158e37e0d7e50df8095942d)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2001 Marcel Moolenaar
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 AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, 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 
29 #include <sys/param.h>
30 #include <sys/lock.h>
31 #include <sys/malloc.h>
32 #include <sys/mutex.h>
33 #include <sys/sysctl.h>
34 #include <sys/sbuf.h>
35 #include <sys/vnode.h>
36 
37 #ifdef COMPAT_LINUX32
38 #include <machine/../linux32/linux.h>
39 #include <machine/../linux32/linux32_proto.h>
40 #else
41 #include <machine/../linux/linux.h>
42 #include <machine/../linux/linux_proto.h>
43 #endif
44 
45 #include <compat/linux/linux_dtrace.h>
46 #include <compat/linux/linux_misc.h>
47 #include <compat/linux/linux_util.h>
48 
49 #define	LINUX_CTL_KERN		1
50 #define	LINUX_CTL_VM		2
51 #define	LINUX_CTL_NET		3
52 #define	LINUX_CTL_PROC		4
53 #define	LINUX_CTL_FS		5
54 #define	LINUX_CTL_DEBUG		6
55 #define	LINUX_CTL_DEV		7
56 #define	LINUX_CTL_BUS		8
57 
58 /* CTL_KERN names */
59 #define	LINUX_KERN_OSTYPE	1
60 #define	LINUX_KERN_OSRELEASE	2
61 #define	LINUX_KERN_OSREV	3
62 #define	LINUX_KERN_VERSION	4
63 
64 /* DTrace init */
65 LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE);
66 
67 /**
68  * DTrace probes in this module.
69  */
70 LIN_SDT_PROBE_DEFINE1(sysctl, handle_string, copyout_error, "int");
71 LIN_SDT_PROBE_DEFINE1(sysctl, linux_sysctl, copyin_error, "int");
72 LIN_SDT_PROBE_DEFINE2(sysctl, linux_sysctl, wrong_length, "int", "int");
73 LIN_SDT_PROBE_DEFINE1(sysctl, linux_sysctl, unsupported_sysctl, "char *");
74 
75 #ifdef LINUX_LEGACY_SYSCALLS
76 static int
77 handle_string(struct l___sysctl_args *la, char *value)
78 {
79 	int error;
80 
81 	if (la->oldval != 0) {
82 		l_int len = strlen(value);
83 		error = copyout(value, PTRIN(la->oldval), len + 1);
84 		if (!error && la->oldlenp != 0)
85 			error = copyout(&len, PTRIN(la->oldlenp), sizeof(len));
86 		if (error) {
87 			LIN_SDT_PROBE1(sysctl, handle_string, copyout_error,
88 			    error);
89 			return (error);
90 		}
91 	}
92 
93 	if (la->newval != 0)
94 		return (ENOTDIR);
95 
96 	return (0);
97 }
98 
99 int
100 linux_sysctl(struct thread *td, struct linux_sysctl_args *args)
101 {
102 	struct l___sysctl_args la;
103 	struct sbuf *sb;
104 	l_int *mib;
105 	char *sysctl_string;
106 	int error, i;
107 
108 	error = copyin(args->args, &la, sizeof(la));
109 	if (error) {
110 		LIN_SDT_PROBE1(sysctl, linux_sysctl, copyin_error, error);
111 		return (error);
112 	}
113 
114 	if (la.nlen <= 0 || la.nlen > LINUX_CTL_MAXNAME) {
115 		LIN_SDT_PROBE2(sysctl, linux_sysctl, wrong_length, la.nlen,
116 		    LINUX_CTL_MAXNAME);
117 		return (ENOTDIR);
118 	}
119 
120 	mib = malloc(la.nlen * sizeof(l_int), M_LINUX, M_WAITOK);
121 	error = copyin(PTRIN(la.name), mib, la.nlen * sizeof(l_int));
122 	if (error) {
123 		LIN_SDT_PROBE1(sysctl, linux_sysctl, copyin_error, error);
124 		free(mib, M_LINUX);
125 		return (error);
126 	}
127 
128 	switch (mib[0]) {
129 	case LINUX_CTL_KERN:
130 		if (la.nlen < 2)
131 			break;
132 
133 		switch (mib[1]) {
134 		case LINUX_KERN_VERSION:
135 			error = handle_string(&la, version);
136 			free(mib, M_LINUX);
137 			return (error);
138 		default:
139 			break;
140 		}
141 		break;
142 	default:
143 		break;
144 	}
145 
146 	sb = sbuf_new(NULL, NULL, 20 + la.nlen * 5, SBUF_AUTOEXTEND);
147 	if (sb == NULL) {
148 		linux_msg(td, "sysctl is not implemented");
149 		LIN_SDT_PROBE1(sysctl, linux_sysctl, unsupported_sysctl,
150 		    "unknown sysctl, ENOMEM during lookup");
151 	} else {
152 		sbuf_printf(sb, "sysctl ");
153 		for (i = 0; i < la.nlen; i++)
154 			sbuf_printf(sb, "%c%d", (i) ? ',' : '{', mib[i]);
155 		sbuf_printf(sb, "} is not implemented");
156 		sbuf_finish(sb);
157 		sysctl_string = sbuf_data(sb);
158 		linux_msg(td, "%s", sysctl_string);
159 		LIN_SDT_PROBE1(sysctl, linux_sysctl, unsupported_sysctl,
160 		    sysctl_string);
161 		sbuf_delete(sb);
162 	}
163 
164 	free(mib, M_LINUX);
165 
166 	return (ENOTDIR);
167 }
168 #endif
169