xref: /freebsd/sys/compat/linux/linux_util.c (revision 2008043f386721d58158e37e0d7e50df8095942d)
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/param.h>
35 #include <sys/bus.h>
36 #include <sys/conf.h>
37 #include <sys/fcntl.h>
38 #include <sys/jail.h>
39 #include <sys/malloc.h>
40 #include <sys/namei.h>
41 #include <sys/proc.h>
42 #include <sys/stat.h>
43 #include <sys/syscallsubr.h>
44 #include <sys/vnode.h>
45 
46 #include <machine/stdarg.h>
47 
48 #include <compat/linux/linux_dtrace.h>
49 #include <compat/linux/linux_mib.h>
50 #include <compat/linux/linux_util.h>
51 
52 MALLOC_DEFINE(M_LINUX, "linux", "Linux mode structures");
53 MALLOC_DEFINE(M_EPOLL, "lepoll", "Linux events structures");
54 
55 FEATURE(linuxulator_v4l, "V4L ioctl wrapper support in the linuxulator");
56 FEATURE(linuxulator_v4l2, "V4L2 ioctl wrapper support in the linuxulator");
57 
58 /**
59  * Special DTrace provider for the linuxulator.
60  *
61  * In this file we define the provider for the entire linuxulator. All
62  * modules (= files of the linuxulator) use it.
63  *
64  * We define a different name depending on the emulated bitsize, see
65  * ../../<ARCH>/linux{,32}/linux.h, e.g.:
66  *      native bitsize          = linuxulator
67  *      amd64, 32bit emulation  = linuxulator32
68  */
69 LIN_SDT_PROVIDER_DEFINE(linuxulator);
70 LIN_SDT_PROVIDER_DEFINE(linuxulator32);
71 
72 char linux_emul_path[MAXPATHLEN] = "/compat/linux";
73 
74 SYSCTL_STRING(_compat_linux, OID_AUTO, emul_path, CTLFLAG_RWTUN,
75     linux_emul_path, sizeof(linux_emul_path),
76     "Linux runtime environment path");
77 
78 int
79 linux_pwd_onexec(struct thread *td)
80 {
81 	struct nameidata nd;
82 	struct pwd *pwd;
83 	int error;
84 
85 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, linux_emul_path);
86 	error = namei(&nd);
87 	if (error != 0) {
88 		/*
89 		 * Do not bother if we are in chroot or jail.
90 		 */
91 		pwd = pwd_hold(td);
92 		if (pwd->pwd_rdir != rootvnode) {
93 			pwd_drop(pwd);
94 			return (0);
95 		}
96 		pwd_drop(pwd);
97 		return (error);
98 	}
99 	NDFREE_PNBUF(&nd);
100 	pwd_altroot(td, nd.ni_vp);
101 	vrele(nd.ni_vp);
102 	return (0);
103 }
104 
105 void
106 linux_pwd_onexec_native(struct thread *td)
107 {
108 
109 	pwd_altroot(td, NULL);
110 }
111 
112 void
113 linux_msg(const struct thread *td, const char *fmt, ...)
114 {
115 	va_list ap;
116 	struct proc *p;
117 
118 	if (linux_debug == 0)
119 		return;
120 
121 	p = td->td_proc;
122 	printf("linux: jid %d pid %d (%s): ", p->p_ucred->cr_prison->pr_id,
123 	    (int)p->p_pid, p->p_comm);
124 	va_start(ap, fmt);
125 	vprintf(fmt, ap);
126 	va_end(ap);
127 	printf("\n");
128 }
129 
130 struct device_element
131 {
132 	TAILQ_ENTRY(device_element) list;
133 	struct linux_device_handler entry;
134 };
135 
136 static TAILQ_HEAD(, device_element) devices =
137 	TAILQ_HEAD_INITIALIZER(devices);
138 
139 static struct linux_device_handler null_handler =
140 	{ "mem", "mem", "null", "null", 1, 3, 1};
141 
142 DATA_SET(linux_device_handler_set, null_handler);
143 
144 char *
145 linux_driver_get_name_dev(device_t dev)
146 {
147 	struct device_element *de;
148 	const char *device_name = device_get_name(dev);
149 
150 	if (device_name == NULL)
151 		return (NULL);
152 	TAILQ_FOREACH(de, &devices, list) {
153 		if (strcmp(device_name, de->entry.bsd_driver_name) == 0)
154 			return (de->entry.linux_driver_name);
155 	}
156 
157 	return (NULL);
158 }
159 
160 int
161 linux_driver_get_major_minor(const char *node, int *major, int *minor)
162 {
163 	struct device_element *de;
164 	unsigned long devno;
165 	size_t sz;
166 
167 	if (node == NULL || major == NULL || minor == NULL)
168 		return (1);
169 
170 	sz = sizeof("pts/") - 1;
171 	if (strncmp(node, "pts/", sz) == 0 && node[sz] != '\0') {
172 		/*
173 		 * Linux checks major and minors of the slave device
174 		 * to make sure it's a pty device, so let's make him
175 		 * believe it is.
176 		 */
177 		devno = strtoul(node + sz, NULL, 10);
178 		*major = 136 + (devno / 256);
179 		*minor = devno % 256;
180 		return (0);
181 	}
182 
183 	sz = sizeof("dri/card") - 1;
184 	if (strncmp(node, "dri/card", sz) == 0 && node[sz] != '\0') {
185 		devno = strtoul(node + sz, NULL, 10);
186 		*major = 226 + (devno / 256);
187 		*minor = devno % 256;
188 		return (0);
189 	}
190 	sz = sizeof("dri/controlD") - 1;
191 	if (strncmp(node, "dri/controlD", sz) == 0 && node[sz] != '\0') {
192 		devno = strtoul(node + sz, NULL, 10);
193 		*major = 226 + (devno / 256);
194 		*minor = devno % 256;
195 		return (0);
196 	}
197 	sz = sizeof("dri/renderD") - 1;
198 	if (strncmp(node, "dri/renderD", sz) == 0 && node[sz] != '\0') {
199 		devno = strtoul(node + sz, NULL, 10);
200 		*major = 226 + (devno / 256);
201 		*minor = devno % 256;
202 		return (0);
203 	}
204 	sz = sizeof("drm/") - 1;
205 	if (strncmp(node, "drm/", sz) == 0 && node[sz] != '\0') {
206 		devno = strtoul(node + sz, NULL, 10);
207 		*major = 226 + (devno / 256);
208 		*minor = devno % 256;
209 		return (0);
210 	}
211 
212 	TAILQ_FOREACH(de, &devices, list) {
213 		if (strcmp(node, de->entry.bsd_device_name) == 0) {
214 			*major = de->entry.linux_major;
215 			*minor = de->entry.linux_minor;
216 			return (0);
217 		}
218 	}
219 
220 	return (1);
221 }
222 
223 int
224 linux_vn_get_major_minor(const struct vnode *vp, int *major, int *minor)
225 {
226 	int error;
227 
228 	if (vp->v_type != VCHR)
229 		return (ENOTBLK);
230 	dev_lock();
231 	if (vp->v_rdev == NULL) {
232 		dev_unlock();
233 		return (ENXIO);
234 	}
235 	error = linux_driver_get_major_minor(devtoname(vp->v_rdev),
236 	    major, minor);
237 	dev_unlock();
238 	return (error);
239 }
240 
241 void
242 translate_vnhook_major_minor(struct vnode *vp, struct stat *sb)
243 {
244 	int major, minor;
245 
246 	if (vn_isdisk(vp)) {
247 		sb->st_mode &= ~S_IFMT;
248 		sb->st_mode |= S_IFBLK;
249 	}
250 
251 	/*
252 	 * Return the same st_dev for every devfs instance.  The reason
253 	 * for this is to work around an idiosyncrasy of glibc getttynam()
254 	 * implementation: it checks whether st_dev returned for fd 0
255 	 * is the same as st_dev returned for the target of /proc/self/fd/0
256 	 * symlink, and with linux chroots having their own devfs instance,
257 	 * the check will fail if you chroot into it.
258 	 */
259 	if (rootdevmp != NULL && vp->v_mount->mnt_vfc == rootdevmp->mnt_vfc)
260 		sb->st_dev = rootdevmp->mnt_stat.f_fsid.val[0];
261 
262 	if (linux_vn_get_major_minor(vp, &major, &minor) == 0)
263 		sb->st_rdev = makedev(major, minor);
264 }
265 
266 char *
267 linux_get_char_devices(void)
268 {
269 	struct device_element *de;
270 	char *temp, *string, *last;
271 	char formated[256];
272 	int current_size = 0, string_size = 1024;
273 
274 	string = malloc(string_size, M_LINUX, M_WAITOK);
275 	string[0] = '\000';
276 	last = "";
277 	TAILQ_FOREACH(de, &devices, list) {
278 		if (!de->entry.linux_char_device)
279 			continue;
280 		temp = string;
281 		if (strcmp(last, de->entry.bsd_driver_name) != 0) {
282 			last = de->entry.bsd_driver_name;
283 
284 			snprintf(formated, sizeof(formated), "%3d %s\n",
285 				 de->entry.linux_major,
286 				 de->entry.linux_device_name);
287 			if (strlen(formated) + current_size
288 			    >= string_size) {
289 				string_size *= 2;
290 				string = malloc(string_size,
291 				    M_LINUX, M_WAITOK);
292 				bcopy(temp, string, current_size);
293 				free(temp, M_LINUX);
294 			}
295 			strcat(string, formated);
296 			current_size = strlen(string);
297 		}
298 	}
299 
300 	return (string);
301 }
302 
303 void
304 linux_free_get_char_devices(char *string)
305 {
306 
307 	free(string, M_LINUX);
308 }
309 
310 static int linux_major_starting = 200;
311 
312 int
313 linux_device_register_handler(struct linux_device_handler *d)
314 {
315 	struct device_element *de;
316 
317 	if (d == NULL)
318 		return (EINVAL);
319 
320 	de = malloc(sizeof(*de), M_LINUX, M_WAITOK);
321 	if (d->linux_major < 0) {
322 		d->linux_major = linux_major_starting++;
323 	}
324 	bcopy(d, &de->entry, sizeof(*d));
325 
326 	/* Add the element to the list, sorted on span. */
327 	TAILQ_INSERT_TAIL(&devices, de, list);
328 
329 	return (0);
330 }
331 
332 int
333 linux_device_unregister_handler(struct linux_device_handler *d)
334 {
335 	struct device_element *de;
336 
337 	if (d == NULL)
338 		return (EINVAL);
339 
340 	TAILQ_FOREACH(de, &devices, list) {
341 		if (bcmp(d, &de->entry, sizeof(*d)) == 0) {
342 			TAILQ_REMOVE(&devices, de, list);
343 			free(de, M_LINUX);
344 
345 			return (0);
346 		}
347 	}
348 
349 	return (EINVAL);
350 }
351