xref: /freebsd/sys/compat/linux/linux_util.c (revision c1839039b193b48c8eb7520c75487f0bd4340c3b)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1994 Christos Zoulas
5  * Copyright (c) 1995 Frank van der Linden
6  * Copyright (c) 1995 Scott Bartram
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. The name of the author may not be used to endorse or promote products
18  *    derived from this software without specific prior written permission
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
21  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
24  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
29  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30  *
31  *	from: svr4_util.c,v 1.5 1995/01/22 23:44:50 christos Exp
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #include <sys/param.h>
38 #include <sys/types.h>
39 #include <sys/bus.h>
40 #include <sys/conf.h>
41 #include <sys/fcntl.h>
42 #include <sys/jail.h>
43 #include <sys/malloc.h>
44 #include <sys/namei.h>
45 #include <sys/proc.h>
46 #include <sys/stat.h>
47 #include <sys/syscallsubr.h>
48 #include <sys/vnode.h>
49 
50 #include <machine/stdarg.h>
51 
52 #include <compat/linux/linux_dtrace.h>
53 #include <compat/linux/linux_mib.h>
54 #include <compat/linux/linux_util.h>
55 
56 MALLOC_DEFINE(M_LINUX, "linux", "Linux mode structures");
57 MALLOC_DEFINE(M_EPOLL, "lepoll", "Linux events structures");
58 
59 FEATURE(linuxulator_v4l, "V4L ioctl wrapper support in the linuxulator");
60 FEATURE(linuxulator_v4l2, "V4L2 ioctl wrapper support in the linuxulator");
61 
62 /**
63  * Special DTrace provider for the linuxulator.
64  *
65  * In this file we define the provider for the entire linuxulator. All
66  * modules (= files of the linuxulator) use it.
67  *
68  * We define a different name depending on the emulated bitsize, see
69  * ../../<ARCH>/linux{,32}/linux.h, e.g.:
70  *      native bitsize          = linuxulator
71  *      amd64, 32bit emulation  = linuxulator32
72  */
73 LIN_SDT_PROVIDER_DEFINE(linuxulator);
74 LIN_SDT_PROVIDER_DEFINE(linuxulator32);
75 
76 char linux_emul_path[MAXPATHLEN] = "/compat/linux";
77 
78 SYSCTL_STRING(_compat_linux, OID_AUTO, emul_path, CTLFLAG_RWTUN,
79     linux_emul_path, sizeof(linux_emul_path),
80     "Linux runtime environment path");
81 
82 int
83 linux_pwd_onexec(struct thread *td)
84 {
85 	struct nameidata nd;
86 	struct pwd *pwd;
87 	int error;
88 
89 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, linux_emul_path);
90 	error = namei(&nd);
91 	if (error != 0) {
92 		/*
93 		 * Do not bother if we are in chroot or jail.
94 		 */
95 		pwd = pwd_hold(td);
96 		if (pwd->pwd_rdir != rootvnode) {
97 			pwd_drop(pwd);
98 			return (0);
99 		}
100 		pwd_drop(pwd);
101 		return (error);
102 	}
103 	NDFREE_PNBUF(&nd);
104 	pwd_altroot(td, nd.ni_vp);
105 	vrele(nd.ni_vp);
106 	return (0);
107 }
108 
109 void
110 linux_pwd_onexec_native(struct thread *td)
111 {
112 
113 	pwd_altroot(td, NULL);
114 }
115 
116 void
117 linux_msg(const struct thread *td, const char *fmt, ...)
118 {
119 	va_list ap;
120 	struct proc *p;
121 
122 	if (linux_debug == 0)
123 		return;
124 
125 	p = td->td_proc;
126 	printf("linux: jid %d pid %d (%s): ", p->p_ucred->cr_prison->pr_id,
127 	    (int)p->p_pid, p->p_comm);
128 	va_start(ap, fmt);
129 	vprintf(fmt, ap);
130 	va_end(ap);
131 	printf("\n");
132 }
133 
134 struct device_element
135 {
136 	TAILQ_ENTRY(device_element) list;
137 	struct linux_device_handler entry;
138 };
139 
140 static TAILQ_HEAD(, device_element) devices =
141 	TAILQ_HEAD_INITIALIZER(devices);
142 
143 static struct linux_device_handler null_handler =
144 	{ "mem", "mem", "null", "null", 1, 3, 1};
145 
146 DATA_SET(linux_device_handler_set, null_handler);
147 
148 char *
149 linux_driver_get_name_dev(device_t dev)
150 {
151 	struct device_element *de;
152 	const char *device_name = device_get_name(dev);
153 
154 	if (device_name == NULL)
155 		return (NULL);
156 	TAILQ_FOREACH(de, &devices, list) {
157 		if (strcmp(device_name, de->entry.bsd_driver_name) == 0)
158 			return (de->entry.linux_driver_name);
159 	}
160 
161 	return (NULL);
162 }
163 
164 int
165 linux_driver_get_major_minor(const char *node, int *major, int *minor)
166 {
167 	struct device_element *de;
168 	unsigned long devno;
169 	size_t sz;
170 
171 	if (node == NULL || major == NULL || minor == NULL)
172 		return (1);
173 
174 	sz = sizeof("pts/") - 1;
175 	if (strncmp(node, "pts/", sz) == 0 && node[sz] != '\0') {
176 		/*
177 		 * Linux checks major and minors of the slave device
178 		 * to make sure it's a pty device, so let's make him
179 		 * believe it is.
180 		 */
181 		devno = strtoul(node + sz, NULL, 10);
182 		*major = 136 + (devno / 256);
183 		*minor = devno % 256;
184 		return (0);
185 	}
186 
187 	sz = sizeof("dri/card") - 1;
188 	if (strncmp(node, "dri/card", sz) == 0 && node[sz] != '\0') {
189 		devno = strtoul(node + sz, NULL, 10);
190 		*major = 226 + (devno / 256);
191 		*minor = devno % 256;
192 		return (0);
193 	}
194 	sz = sizeof("dri/controlD") - 1;
195 	if (strncmp(node, "dri/controlD", sz) == 0 && node[sz] != '\0') {
196 		devno = strtoul(node + sz, NULL, 10);
197 		*major = 226 + (devno / 256);
198 		*minor = devno % 256;
199 		return (0);
200 	}
201 	sz = sizeof("dri/renderD") - 1;
202 	if (strncmp(node, "dri/renderD", sz) == 0 && node[sz] != '\0') {
203 		devno = strtoul(node + sz, NULL, 10);
204 		*major = 226 + (devno / 256);
205 		*minor = devno % 256;
206 		return (0);
207 	}
208 	sz = sizeof("drm/") - 1;
209 	if (strncmp(node, "drm/", sz) == 0 && node[sz] != '\0') {
210 		devno = strtoul(node + sz, NULL, 10);
211 		*major = 226 + (devno / 256);
212 		*minor = devno % 256;
213 		return (0);
214 	}
215 
216 	TAILQ_FOREACH(de, &devices, list) {
217 		if (strcmp(node, de->entry.bsd_device_name) == 0) {
218 			*major = de->entry.linux_major;
219 			*minor = de->entry.linux_minor;
220 			return (0);
221 		}
222 	}
223 
224 	return (1);
225 }
226 
227 int
228 linux_vn_get_major_minor(const struct vnode *vp, int *major, int *minor)
229 {
230 	int error;
231 
232 	if (vp->v_type != VCHR)
233 		return (ENOTBLK);
234 	dev_lock();
235 	if (vp->v_rdev == NULL) {
236 		dev_unlock();
237 		return (ENXIO);
238 	}
239 	error = linux_driver_get_major_minor(devtoname(vp->v_rdev),
240 	    major, minor);
241 	dev_unlock();
242 	return (error);
243 }
244 
245 void
246 translate_vnhook_major_minor(struct vnode *vp, struct stat *sb)
247 {
248 	int major, minor;
249 
250 	if (vn_isdisk(vp)) {
251 		sb->st_mode &= ~S_IFMT;
252 		sb->st_mode |= S_IFBLK;
253 	}
254 
255 	/*
256 	 * Return the same st_dev for every devfs instance.  The reason
257 	 * for this is to work around an idiosyncrasy of glibc getttynam()
258 	 * implementation: it checks whether st_dev returned for fd 0
259 	 * is the same as st_dev returned for the target of /proc/self/fd/0
260 	 * symlink, and with linux chroots having their own devfs instance,
261 	 * the check will fail if you chroot into it.
262 	 */
263 	if (rootdevmp != NULL && vp->v_mount->mnt_vfc == rootdevmp->mnt_vfc)
264 		sb->st_dev = rootdevmp->mnt_stat.f_fsid.val[0];
265 
266 	if (linux_vn_get_major_minor(vp, &major, &minor) == 0)
267 		sb->st_rdev = makedev(major, minor);
268 }
269 
270 char *
271 linux_get_char_devices(void)
272 {
273 	struct device_element *de;
274 	char *temp, *string, *last;
275 	char formated[256];
276 	int current_size = 0, string_size = 1024;
277 
278 	string = malloc(string_size, M_LINUX, M_WAITOK);
279 	string[0] = '\000';
280 	last = "";
281 	TAILQ_FOREACH(de, &devices, list) {
282 		if (!de->entry.linux_char_device)
283 			continue;
284 		temp = string;
285 		if (strcmp(last, de->entry.bsd_driver_name) != 0) {
286 			last = de->entry.bsd_driver_name;
287 
288 			snprintf(formated, sizeof(formated), "%3d %s\n",
289 				 de->entry.linux_major,
290 				 de->entry.linux_device_name);
291 			if (strlen(formated) + current_size
292 			    >= string_size) {
293 				string_size *= 2;
294 				string = malloc(string_size,
295 				    M_LINUX, M_WAITOK);
296 				bcopy(temp, string, current_size);
297 				free(temp, M_LINUX);
298 			}
299 			strcat(string, formated);
300 			current_size = strlen(string);
301 		}
302 	}
303 
304 	return (string);
305 }
306 
307 void
308 linux_free_get_char_devices(char *string)
309 {
310 
311 	free(string, M_LINUX);
312 }
313 
314 static int linux_major_starting = 200;
315 
316 int
317 linux_device_register_handler(struct linux_device_handler *d)
318 {
319 	struct device_element *de;
320 
321 	if (d == NULL)
322 		return (EINVAL);
323 
324 	de = malloc(sizeof(*de), M_LINUX, M_WAITOK);
325 	if (d->linux_major < 0) {
326 		d->linux_major = linux_major_starting++;
327 	}
328 	bcopy(d, &de->entry, sizeof(*d));
329 
330 	/* Add the element to the list, sorted on span. */
331 	TAILQ_INSERT_TAIL(&devices, de, list);
332 
333 	return (0);
334 }
335 
336 int
337 linux_device_unregister_handler(struct linux_device_handler *d)
338 {
339 	struct device_element *de;
340 
341 	if (d == NULL)
342 		return (EINVAL);
343 
344 	TAILQ_FOREACH(de, &devices, list) {
345 		if (bcmp(d, &de->entry, sizeof(*d)) == 0) {
346 			TAILQ_REMOVE(&devices, de, list);
347 			free(de, M_LINUX);
348 
349 			return (0);
350 		}
351 	}
352 
353 	return (EINVAL);
354 }
355