xref: /freebsd/sys/compat/linux/linux_util.c (revision 2a9021898c4ee2154787da862c238cfeccd655df)
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/types.h>
36 #include <sys/bus.h>
37 #include <sys/conf.h>
38 #include <sys/fcntl.h>
39 #include <sys/jail.h>
40 #include <sys/malloc.h>
41 #include <sys/namei.h>
42 #include <sys/proc.h>
43 #include <sys/stat.h>
44 #include <sys/syscallsubr.h>
45 #include <sys/vnode.h>
46 
47 #include <machine/stdarg.h>
48 
49 #include <compat/linux/linux_dtrace.h>
50 #include <compat/linux/linux_mib.h>
51 #include <compat/linux/linux_util.h>
52 
53 MALLOC_DEFINE(M_LINUX, "linux", "Linux mode structures");
54 MALLOC_DEFINE(M_EPOLL, "lepoll", "Linux events structures");
55 
56 FEATURE(linuxulator_v4l, "V4L ioctl wrapper support in the linuxulator");
57 FEATURE(linuxulator_v4l2, "V4L2 ioctl wrapper support in the linuxulator");
58 
59 /**
60  * Special DTrace provider for the linuxulator.
61  *
62  * In this file we define the provider for the entire linuxulator. All
63  * modules (= files of the linuxulator) use it.
64  *
65  * We define a different name depending on the emulated bitsize, see
66  * ../../<ARCH>/linux{,32}/linux.h, e.g.:
67  *      native bitsize          = linuxulator
68  *      amd64, 32bit emulation  = linuxulator32
69  */
70 LIN_SDT_PROVIDER_DEFINE(linuxulator);
71 LIN_SDT_PROVIDER_DEFINE(linuxulator32);
72 
73 char linux_emul_path[MAXPATHLEN] = "/compat/linux";
74 
75 SYSCTL_STRING(_compat_linux, OID_AUTO, emul_path, CTLFLAG_RWTUN,
76     linux_emul_path, sizeof(linux_emul_path),
77     "Linux runtime environment path");
78 
79 int
80 linux_pwd_onexec(struct thread *td)
81 {
82 	struct nameidata nd;
83 	struct pwd *pwd;
84 	int error;
85 
86 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, linux_emul_path);
87 	error = namei(&nd);
88 	if (error != 0) {
89 		/*
90 		 * Do not bother if we are in chroot or jail.
91 		 */
92 		pwd = pwd_hold(td);
93 		if (pwd->pwd_rdir != rootvnode) {
94 			pwd_drop(pwd);
95 			return (0);
96 		}
97 		pwd_drop(pwd);
98 		return (error);
99 	}
100 	NDFREE_PNBUF(&nd);
101 	pwd_altroot(td, nd.ni_vp);
102 	vrele(nd.ni_vp);
103 	return (0);
104 }
105 
106 void
107 linux_pwd_onexec_native(struct thread *td)
108 {
109 
110 	pwd_altroot(td, NULL);
111 }
112 
113 void
114 linux_msg(const struct thread *td, const char *fmt, ...)
115 {
116 	va_list ap;
117 	struct proc *p;
118 
119 	if (linux_debug == 0)
120 		return;
121 
122 	p = td->td_proc;
123 	printf("linux: jid %d pid %d (%s): ", p->p_ucred->cr_prison->pr_id,
124 	    (int)p->p_pid, p->p_comm);
125 	va_start(ap, fmt);
126 	vprintf(fmt, ap);
127 	va_end(ap);
128 	printf("\n");
129 }
130 
131 struct device_element
132 {
133 	TAILQ_ENTRY(device_element) list;
134 	struct linux_device_handler entry;
135 };
136 
137 static TAILQ_HEAD(, device_element) devices =
138 	TAILQ_HEAD_INITIALIZER(devices);
139 
140 static struct linux_device_handler null_handler =
141 	{ "mem", "mem", "null", "null", 1, 3, 1};
142 
143 DATA_SET(linux_device_handler_set, null_handler);
144 
145 char *
146 linux_driver_get_name_dev(device_t dev)
147 {
148 	struct device_element *de;
149 	const char *device_name = device_get_name(dev);
150 
151 	if (device_name == NULL)
152 		return (NULL);
153 	TAILQ_FOREACH(de, &devices, list) {
154 		if (strcmp(device_name, de->entry.bsd_driver_name) == 0)
155 			return (de->entry.linux_driver_name);
156 	}
157 
158 	return (NULL);
159 }
160 
161 int
162 linux_driver_get_major_minor(const char *node, int *major, int *minor)
163 {
164 	struct device_element *de;
165 	unsigned long devno;
166 	size_t sz;
167 
168 	if (node == NULL || major == NULL || minor == NULL)
169 		return (1);
170 
171 	sz = sizeof("pts/") - 1;
172 	if (strncmp(node, "pts/", sz) == 0 && node[sz] != '\0') {
173 		/*
174 		 * Linux checks major and minors of the slave device
175 		 * to make sure it's a pty device, so let's make him
176 		 * believe it is.
177 		 */
178 		devno = strtoul(node + sz, NULL, 10);
179 		*major = 136 + (devno / 256);
180 		*minor = devno % 256;
181 		return (0);
182 	}
183 
184 	sz = sizeof("dri/card") - 1;
185 	if (strncmp(node, "dri/card", sz) == 0 && node[sz] != '\0') {
186 		devno = strtoul(node + sz, NULL, 10);
187 		*major = 226 + (devno / 256);
188 		*minor = devno % 256;
189 		return (0);
190 	}
191 	sz = sizeof("dri/controlD") - 1;
192 	if (strncmp(node, "dri/controlD", sz) == 0 && node[sz] != '\0') {
193 		devno = strtoul(node + sz, NULL, 10);
194 		*major = 226 + (devno / 256);
195 		*minor = devno % 256;
196 		return (0);
197 	}
198 	sz = sizeof("dri/renderD") - 1;
199 	if (strncmp(node, "dri/renderD", sz) == 0 && node[sz] != '\0') {
200 		devno = strtoul(node + sz, NULL, 10);
201 		*major = 226 + (devno / 256);
202 		*minor = devno % 256;
203 		return (0);
204 	}
205 	sz = sizeof("drm/") - 1;
206 	if (strncmp(node, "drm/", sz) == 0 && node[sz] != '\0') {
207 		devno = strtoul(node + sz, NULL, 10);
208 		*major = 226 + (devno / 256);
209 		*minor = devno % 256;
210 		return (0);
211 	}
212 
213 	TAILQ_FOREACH(de, &devices, list) {
214 		if (strcmp(node, de->entry.bsd_device_name) == 0) {
215 			*major = de->entry.linux_major;
216 			*minor = de->entry.linux_minor;
217 			return (0);
218 		}
219 	}
220 
221 	return (1);
222 }
223 
224 int
225 linux_vn_get_major_minor(const struct vnode *vp, int *major, int *minor)
226 {
227 	int error;
228 
229 	if (vp->v_type != VCHR)
230 		return (ENOTBLK);
231 	dev_lock();
232 	if (vp->v_rdev == NULL) {
233 		dev_unlock();
234 		return (ENXIO);
235 	}
236 	error = linux_driver_get_major_minor(devtoname(vp->v_rdev),
237 	    major, minor);
238 	dev_unlock();
239 	return (error);
240 }
241 
242 void
243 translate_vnhook_major_minor(struct vnode *vp, struct stat *sb)
244 {
245 	int major, minor;
246 
247 	if (vn_isdisk(vp)) {
248 		sb->st_mode &= ~S_IFMT;
249 		sb->st_mode |= S_IFBLK;
250 	}
251 
252 	/*
253 	 * Return the same st_dev for every devfs instance.  The reason
254 	 * for this is to work around an idiosyncrasy of glibc getttynam()
255 	 * implementation: it checks whether st_dev returned for fd 0
256 	 * is the same as st_dev returned for the target of /proc/self/fd/0
257 	 * symlink, and with linux chroots having their own devfs instance,
258 	 * the check will fail if you chroot into it.
259 	 */
260 	if (rootdevmp != NULL && vp->v_mount->mnt_vfc == rootdevmp->mnt_vfc)
261 		sb->st_dev = rootdevmp->mnt_stat.f_fsid.val[0];
262 
263 	if (linux_vn_get_major_minor(vp, &major, &minor) == 0)
264 		sb->st_rdev = makedev(major, minor);
265 }
266 
267 char *
268 linux_get_char_devices(void)
269 {
270 	struct device_element *de;
271 	char *temp, *string, *last;
272 	char formated[256];
273 	int current_size = 0, string_size = 1024;
274 
275 	string = malloc(string_size, M_LINUX, M_WAITOK);
276 	string[0] = '\000';
277 	last = "";
278 	TAILQ_FOREACH(de, &devices, list) {
279 		if (!de->entry.linux_char_device)
280 			continue;
281 		temp = string;
282 		if (strcmp(last, de->entry.bsd_driver_name) != 0) {
283 			last = de->entry.bsd_driver_name;
284 
285 			snprintf(formated, sizeof(formated), "%3d %s\n",
286 				 de->entry.linux_major,
287 				 de->entry.linux_device_name);
288 			if (strlen(formated) + current_size
289 			    >= string_size) {
290 				string_size *= 2;
291 				string = malloc(string_size,
292 				    M_LINUX, M_WAITOK);
293 				bcopy(temp, string, current_size);
294 				free(temp, M_LINUX);
295 			}
296 			strcat(string, formated);
297 			current_size = strlen(string);
298 		}
299 	}
300 
301 	return (string);
302 }
303 
304 void
305 linux_free_get_char_devices(char *string)
306 {
307 
308 	free(string, M_LINUX);
309 }
310 
311 static int linux_major_starting = 200;
312 
313 int
314 linux_device_register_handler(struct linux_device_handler *d)
315 {
316 	struct device_element *de;
317 
318 	if (d == NULL)
319 		return (EINVAL);
320 
321 	de = malloc(sizeof(*de), M_LINUX, M_WAITOK);
322 	if (d->linux_major < 0) {
323 		d->linux_major = linux_major_starting++;
324 	}
325 	bcopy(d, &de->entry, sizeof(*d));
326 
327 	/* Add the element to the list, sorted on span. */
328 	TAILQ_INSERT_TAIL(&devices, de, list);
329 
330 	return (0);
331 }
332 
333 int
334 linux_device_unregister_handler(struct linux_device_handler *d)
335 {
336 	struct device_element *de;
337 
338 	if (d == NULL)
339 		return (EINVAL);
340 
341 	TAILQ_FOREACH(de, &devices, list) {
342 		if (bcmp(d, &de->entry, sizeof(*d)) == 0) {
343 			TAILQ_REMOVE(&devices, de, list);
344 			free(de, M_LINUX);
345 
346 			return (0);
347 		}
348 	}
349 
350 	return (EINVAL);
351 }
352