xref: /freebsd/sys/compat/linux/linux_sysctl.c (revision 1de7b4b805ddbf2429da511c053686ac4591ed89)
1 /*-
2  * SPDX-License-Identifier: BSD-3-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  *    in this position and unchanged.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. The name of the author may not be used to endorse or promote products
17  *    derived from this software without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include "opt_compat.h"
35 
36 #include <sys/param.h>
37 #include <sys/kernel.h>
38 #include <sys/lock.h>
39 #include <sys/malloc.h>
40 #include <sys/mutex.h>
41 #include <sys/proc.h>
42 #include <sys/sdt.h>
43 #include <sys/sysctl.h>
44 #include <sys/systm.h>
45 #include <sys/sbuf.h>
46 
47 #ifdef COMPAT_LINUX32
48 #include <machine/../linux32/linux.h>
49 #include <machine/../linux32/linux32_proto.h>
50 #else
51 #include <machine/../linux/linux.h>
52 #include <machine/../linux/linux_proto.h>
53 #endif
54 
55 #include <compat/linux/linux_dtrace.h>
56 #include <compat/linux/linux_misc.h>
57 #include <compat/linux/linux_util.h>
58 
59 #define	LINUX_CTL_KERN		1
60 #define	LINUX_CTL_VM		2
61 #define	LINUX_CTL_NET		3
62 #define	LINUX_CTL_PROC		4
63 #define	LINUX_CTL_FS		5
64 #define	LINUX_CTL_DEBUG		6
65 #define	LINUX_CTL_DEV		7
66 #define	LINUX_CTL_BUS		8
67 
68 /* CTL_KERN names */
69 #define	LINUX_KERN_OSTYPE	1
70 #define	LINUX_KERN_OSRELEASE	2
71 #define	LINUX_KERN_OSREV	3
72 #define	LINUX_KERN_VERSION	4
73 
74 /* DTrace init */
75 LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE);
76 
77 /**
78  * DTrace probes in this module.
79  */
80 LIN_SDT_PROBE_DEFINE2(sysctl, handle_string, entry, "struct l___sysctl_args *",
81     "char *");
82 LIN_SDT_PROBE_DEFINE1(sysctl, handle_string, copyout_error, "int");
83 LIN_SDT_PROBE_DEFINE1(sysctl, handle_string, return, "int");
84 LIN_SDT_PROBE_DEFINE2(sysctl, linux_sysctl, entry, "struct l___sysctl_args *",
85     "struct thread *");
86 LIN_SDT_PROBE_DEFINE1(sysctl, linux_sysctl, copyin_error, "int");
87 LIN_SDT_PROBE_DEFINE2(sysctl, linux_sysctl, wrong_length, "int", "int");
88 LIN_SDT_PROBE_DEFINE1(sysctl, linux_sysctl, unsupported_sysctl, "char *");
89 LIN_SDT_PROBE_DEFINE1(sysctl, linux_sysctl, return, "int");
90 
91 static int
92 handle_string(struct l___sysctl_args *la, char *value)
93 {
94 	int error;
95 
96 	LIN_SDT_PROBE2(sysctl, handle_string, entry, la, value);
97 
98 	if (la->oldval != 0) {
99 		l_int len = strlen(value);
100 		error = copyout(value, PTRIN(la->oldval), len + 1);
101 		if (!error && la->oldlenp != 0)
102 			error = copyout(&len, PTRIN(la->oldlenp), sizeof(len));
103 		if (error) {
104 			LIN_SDT_PROBE1(sysctl, handle_string, copyout_error,
105 			    error);
106 			LIN_SDT_PROBE1(sysctl, handle_string, return, error);
107 			return (error);
108 		}
109 	}
110 
111 	if (la->newval != 0) {
112 		LIN_SDT_PROBE1(sysctl, handle_string, return, ENOTDIR);
113 		return (ENOTDIR);
114 	}
115 
116 	LIN_SDT_PROBE1(sysctl, handle_string, return, 0);
117 	return (0);
118 }
119 
120 int
121 linux_sysctl(struct thread *td, struct linux_sysctl_args *args)
122 {
123 	struct l___sysctl_args la;
124 	struct sbuf *sb;
125 	l_int *mib;
126 	char *sysctl_string;
127 	int error, i;
128 
129 	LIN_SDT_PROBE2(sysctl, linux_sysctl, entry, td, args->args);
130 
131 	error = copyin(args->args, &la, sizeof(la));
132 	if (error) {
133 		LIN_SDT_PROBE1(sysctl, linux_sysctl, copyin_error, error);
134 		LIN_SDT_PROBE1(sysctl, linux_sysctl, return, error);
135 		return (error);
136 	}
137 
138 	if (la.nlen <= 0 || la.nlen > LINUX_CTL_MAXNAME) {
139 		LIN_SDT_PROBE2(sysctl, linux_sysctl, wrong_length, la.nlen,
140 		    LINUX_CTL_MAXNAME);
141 		LIN_SDT_PROBE1(sysctl, linux_sysctl, return, ENOTDIR);
142 		return (ENOTDIR);
143 	}
144 
145 	mib = malloc(la.nlen * sizeof(l_int), M_LINUX, M_WAITOK);
146 	error = copyin(PTRIN(la.name), mib, la.nlen * sizeof(l_int));
147 	if (error) {
148 		LIN_SDT_PROBE1(sysctl, linux_sysctl, copyin_error, error);
149 		LIN_SDT_PROBE1(sysctl, linux_sysctl, return, error);
150 		free(mib, M_LINUX);
151 		return (error);
152 	}
153 
154 	switch (mib[0]) {
155 	case LINUX_CTL_KERN:
156 		if (la.nlen < 2)
157 			break;
158 
159 		switch (mib[1]) {
160 		case LINUX_KERN_VERSION:
161 			error = handle_string(&la, version);
162 			free(mib, M_LINUX);
163 			LIN_SDT_PROBE1(sysctl, linux_sysctl, return, error);
164 			return (error);
165 		default:
166 			break;
167 		}
168 		break;
169 	default:
170 		break;
171 	}
172 
173 	sb = sbuf_new(NULL, NULL, 20 + la.nlen * 5, SBUF_AUTOEXTEND);
174 	if (sb == NULL) {
175 		linux_msg(td, "sysctl is not implemented");
176 		LIN_SDT_PROBE1(sysctl, linux_sysctl, unsupported_sysctl,
177 		    "unknown sysctl, ENOMEM during lookup");
178 	} else {
179 		sbuf_printf(sb, "sysctl ");
180 		for (i = 0; i < la.nlen; i++)
181 			sbuf_printf(sb, "%c%d", (i) ? ',' : '{', mib[i]);
182 		sbuf_printf(sb, "} is not implemented");
183 		sbuf_finish(sb);
184 		sysctl_string = sbuf_data(sb);
185 		linux_msg(td, "%s", sbuf_data(sb));
186 		LIN_SDT_PROBE1(sysctl, linux_sysctl, unsupported_sysctl,
187 		    sysctl_string);
188 		sbuf_delete(sb);
189 	}
190 
191 	free(mib, M_LINUX);
192 
193 	LIN_SDT_PROBE1(sysctl, linux_sysctl, return, ENOTDIR);
194 	return (ENOTDIR);
195 }
196