xref: /freebsd/sys/compat/linux/linux_util.c (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)
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 #include <sys/param.h>
36 #include <sys/types.h>
37 #include <sys/bus.h>
38 #include <sys/conf.h>
39 #include <sys/fcntl.h>
40 #include <sys/jail.h>
41 #include <sys/malloc.h>
42 #include <sys/namei.h>
43 #include <sys/proc.h>
44 #include <sys/stat.h>
45 #include <sys/syscallsubr.h>
46 #include <sys/vnode.h>
47 
48 #include <machine/stdarg.h>
49 
50 #include <compat/linux/linux_dtrace.h>
51 #include <compat/linux/linux_mib.h>
52 #include <compat/linux/linux_util.h>
53 
54 MALLOC_DEFINE(M_LINUX, "linux", "Linux mode structures");
55 MALLOC_DEFINE(M_EPOLL, "lepoll", "Linux events structures");
56 
57 FEATURE(linuxulator_v4l, "V4L ioctl wrapper support in the linuxulator");
58 FEATURE(linuxulator_v4l2, "V4L2 ioctl wrapper support in the linuxulator");
59 
60 /**
61  * Special DTrace provider for the linuxulator.
62  *
63  * In this file we define the provider for the entire linuxulator. All
64  * modules (= files of the linuxulator) use it.
65  *
66  * We define a different name depending on the emulated bitsize, see
67  * ../../<ARCH>/linux{,32}/linux.h, e.g.:
68  *      native bitsize          = linuxulator
69  *      amd64, 32bit emulation  = linuxulator32
70  */
71 LIN_SDT_PROVIDER_DEFINE(linuxulator);
72 LIN_SDT_PROVIDER_DEFINE(linuxulator32);
73 
74 char linux_emul_path[MAXPATHLEN] = "/compat/linux";
75 
76 SYSCTL_STRING(_compat_linux, OID_AUTO, emul_path, CTLFLAG_RWTUN,
77     linux_emul_path, sizeof(linux_emul_path),
78     "Linux runtime environment path");
79 
80 int
81 linux_pwd_onexec(struct thread *td)
82 {
83 	struct nameidata nd;
84 	struct pwd *pwd;
85 	int error;
86 
87 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, linux_emul_path);
88 	error = namei(&nd);
89 	if (error != 0) {
90 		/*
91 		 * Do not bother if we are in chroot or jail.
92 		 */
93 		pwd = pwd_hold(td);
94 		if (pwd->pwd_rdir != rootvnode) {
95 			pwd_drop(pwd);
96 			return (0);
97 		}
98 		pwd_drop(pwd);
99 		return (error);
100 	}
101 	NDFREE_PNBUF(&nd);
102 	pwd_altroot(td, nd.ni_vp);
103 	vrele(nd.ni_vp);
104 	return (0);
105 }
106 
107 void
108 linux_pwd_onexec_native(struct thread *td)
109 {
110 
111 	pwd_altroot(td, NULL);
112 }
113 
114 void
115 linux_msg(const struct thread *td, const char *fmt, ...)
116 {
117 	va_list ap;
118 	struct proc *p;
119 
120 	if (linux_debug == 0)
121 		return;
122 
123 	p = td->td_proc;
124 	printf("linux: jid %d pid %d (%s): ", p->p_ucred->cr_prison->pr_id,
125 	    (int)p->p_pid, p->p_comm);
126 	va_start(ap, fmt);
127 	vprintf(fmt, ap);
128 	va_end(ap);
129 	printf("\n");
130 }
131 
132 struct device_element
133 {
134 	TAILQ_ENTRY(device_element) list;
135 	struct linux_device_handler entry;
136 };
137 
138 static TAILQ_HEAD(, device_element) devices =
139 	TAILQ_HEAD_INITIALIZER(devices);
140 
141 static struct linux_device_handler null_handler =
142 	{ "mem", "mem", "null", "null", 1, 3, 1};
143 
144 DATA_SET(linux_device_handler_set, null_handler);
145 
146 char *
147 linux_driver_get_name_dev(device_t dev)
148 {
149 	struct device_element *de;
150 	const char *device_name = device_get_name(dev);
151 
152 	if (device_name == NULL)
153 		return (NULL);
154 	TAILQ_FOREACH(de, &devices, list) {
155 		if (strcmp(device_name, de->entry.bsd_driver_name) == 0)
156 			return (de->entry.linux_driver_name);
157 	}
158 
159 	return (NULL);
160 }
161 
162 int
163 linux_driver_get_major_minor(const char *node, int *major, int *minor)
164 {
165 	struct device_element *de;
166 	unsigned long devno;
167 	size_t sz;
168 
169 	if (node == NULL || major == NULL || minor == NULL)
170 		return (1);
171 
172 	sz = sizeof("pts/") - 1;
173 	if (strncmp(node, "pts/", sz) == 0 && node[sz] != '\0') {
174 		/*
175 		 * Linux checks major and minors of the slave device
176 		 * to make sure it's a pty device, so let's make him
177 		 * believe it is.
178 		 */
179 		devno = strtoul(node + sz, NULL, 10);
180 		*major = 136 + (devno / 256);
181 		*minor = devno % 256;
182 		return (0);
183 	}
184 
185 	sz = sizeof("dri/card") - 1;
186 	if (strncmp(node, "dri/card", sz) == 0 && node[sz] != '\0') {
187 		devno = strtoul(node + sz, NULL, 10);
188 		*major = 226 + (devno / 256);
189 		*minor = devno % 256;
190 		return (0);
191 	}
192 	sz = sizeof("dri/controlD") - 1;
193 	if (strncmp(node, "dri/controlD", sz) == 0 && node[sz] != '\0') {
194 		devno = strtoul(node + sz, NULL, 10);
195 		*major = 226 + (devno / 256);
196 		*minor = devno % 256;
197 		return (0);
198 	}
199 	sz = sizeof("dri/renderD") - 1;
200 	if (strncmp(node, "dri/renderD", sz) == 0 && node[sz] != '\0') {
201 		devno = strtoul(node + sz, NULL, 10);
202 		*major = 226 + (devno / 256);
203 		*minor = devno % 256;
204 		return (0);
205 	}
206 	sz = sizeof("drm/") - 1;
207 	if (strncmp(node, "drm/", sz) == 0 && node[sz] != '\0') {
208 		devno = strtoul(node + sz, NULL, 10);
209 		*major = 226 + (devno / 256);
210 		*minor = devno % 256;
211 		return (0);
212 	}
213 
214 	TAILQ_FOREACH(de, &devices, list) {
215 		if (strcmp(node, de->entry.bsd_device_name) == 0) {
216 			*major = de->entry.linux_major;
217 			*minor = de->entry.linux_minor;
218 			return (0);
219 		}
220 	}
221 
222 	return (1);
223 }
224 
225 int
226 linux_vn_get_major_minor(const struct vnode *vp, int *major, int *minor)
227 {
228 	int error;
229 
230 	if (vp->v_type != VCHR)
231 		return (ENOTBLK);
232 	dev_lock();
233 	if (vp->v_rdev == NULL) {
234 		dev_unlock();
235 		return (ENXIO);
236 	}
237 	error = linux_driver_get_major_minor(devtoname(vp->v_rdev),
238 	    major, minor);
239 	dev_unlock();
240 	return (error);
241 }
242 
243 void
244 translate_vnhook_major_minor(struct vnode *vp, struct stat *sb)
245 {
246 	int major, minor;
247 
248 	if (vn_isdisk(vp)) {
249 		sb->st_mode &= ~S_IFMT;
250 		sb->st_mode |= S_IFBLK;
251 	}
252 
253 	/*
254 	 * Return the same st_dev for every devfs instance.  The reason
255 	 * for this is to work around an idiosyncrasy of glibc getttynam()
256 	 * implementation: it checks whether st_dev returned for fd 0
257 	 * is the same as st_dev returned for the target of /proc/self/fd/0
258 	 * symlink, and with linux chroots having their own devfs instance,
259 	 * the check will fail if you chroot into it.
260 	 */
261 	if (rootdevmp != NULL && vp->v_mount->mnt_vfc == rootdevmp->mnt_vfc)
262 		sb->st_dev = rootdevmp->mnt_stat.f_fsid.val[0];
263 
264 	if (linux_vn_get_major_minor(vp, &major, &minor) == 0)
265 		sb->st_rdev = makedev(major, minor);
266 }
267 
268 char *
269 linux_get_char_devices(void)
270 {
271 	struct device_element *de;
272 	char *temp, *string, *last;
273 	char formated[256];
274 	int current_size = 0, string_size = 1024;
275 
276 	string = malloc(string_size, M_LINUX, M_WAITOK);
277 	string[0] = '\000';
278 	last = "";
279 	TAILQ_FOREACH(de, &devices, list) {
280 		if (!de->entry.linux_char_device)
281 			continue;
282 		temp = string;
283 		if (strcmp(last, de->entry.bsd_driver_name) != 0) {
284 			last = de->entry.bsd_driver_name;
285 
286 			snprintf(formated, sizeof(formated), "%3d %s\n",
287 				 de->entry.linux_major,
288 				 de->entry.linux_device_name);
289 			if (strlen(formated) + current_size
290 			    >= string_size) {
291 				string_size *= 2;
292 				string = malloc(string_size,
293 				    M_LINUX, M_WAITOK);
294 				bcopy(temp, string, current_size);
295 				free(temp, M_LINUX);
296 			}
297 			strcat(string, formated);
298 			current_size = strlen(string);
299 		}
300 	}
301 
302 	return (string);
303 }
304 
305 void
306 linux_free_get_char_devices(char *string)
307 {
308 
309 	free(string, M_LINUX);
310 }
311 
312 static int linux_major_starting = 200;
313 
314 int
315 linux_device_register_handler(struct linux_device_handler *d)
316 {
317 	struct device_element *de;
318 
319 	if (d == NULL)
320 		return (EINVAL);
321 
322 	de = malloc(sizeof(*de), M_LINUX, M_WAITOK);
323 	if (d->linux_major < 0) {
324 		d->linux_major = linux_major_starting++;
325 	}
326 	bcopy(d, &de->entry, sizeof(*d));
327 
328 	/* Add the element to the list, sorted on span. */
329 	TAILQ_INSERT_TAIL(&devices, de, list);
330 
331 	return (0);
332 }
333 
334 int
335 linux_device_unregister_handler(struct linux_device_handler *d)
336 {
337 	struct device_element *de;
338 
339 	if (d == NULL)
340 		return (EINVAL);
341 
342 	TAILQ_FOREACH(de, &devices, list) {
343 		if (bcmp(d, &de->entry, sizeof(*d)) == 0) {
344 			TAILQ_REMOVE(&devices, de, list);
345 			free(de, M_LINUX);
346 
347 			return (0);
348 		}
349 	}
350 
351 	return (EINVAL);
352 }
353