xref: /freebsd/sys/compat/linux/linux_util.c (revision 99fa799a19abeb70b1034f65407c276b64709bdc)
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 	int error;
83 
84 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, linux_emul_path);
85 	error = namei(&nd);
86 	if (error != 0) {
87 		/* Do not prevent execution if altroot is non-existent. */
88 		pwd_altroot(td, NULL);
89 		return (0);
90 	}
91 	NDFREE_PNBUF(&nd);
92 	pwd_altroot(td, nd.ni_vp);
93 	vrele(nd.ni_vp);
94 	return (0);
95 }
96 
97 void
98 linux_pwd_onexec_native(struct thread *td)
99 {
100 
101 	pwd_altroot(td, NULL);
102 }
103 
104 void
105 linux_msg(const struct thread *td, const char *fmt, ...)
106 {
107 	va_list ap;
108 	struct proc *p;
109 
110 	if (linux_debug == 0)
111 		return;
112 
113 	p = td->td_proc;
114 	printf("linux: jid %d pid %d (%s): ", p->p_ucred->cr_prison->pr_id,
115 	    (int)p->p_pid, p->p_comm);
116 	va_start(ap, fmt);
117 	vprintf(fmt, ap);
118 	va_end(ap);
119 	printf("\n");
120 }
121 
122 struct device_element
123 {
124 	TAILQ_ENTRY(device_element) list;
125 	struct linux_device_handler entry;
126 };
127 
128 static TAILQ_HEAD(, device_element) devices =
129 	TAILQ_HEAD_INITIALIZER(devices);
130 
131 static struct linux_device_handler null_handler =
132 	{ "mem", "mem", "null", "null", 1, 3, 1};
133 
134 DATA_SET(linux_device_handler_set, null_handler);
135 
136 char *
137 linux_driver_get_name_dev(device_t dev)
138 {
139 	struct device_element *de;
140 	const char *device_name = device_get_name(dev);
141 
142 	if (device_name == NULL)
143 		return (NULL);
144 	TAILQ_FOREACH(de, &devices, list) {
145 		if (strcmp(device_name, de->entry.bsd_driver_name) == 0)
146 			return (de->entry.linux_driver_name);
147 	}
148 
149 	return (NULL);
150 }
151 
152 int
153 linux_driver_get_major_minor(const char *node, int *major, int *minor)
154 {
155 	struct device_element *de;
156 	unsigned long devno;
157 	size_t sz;
158 
159 	if (node == NULL || major == NULL || minor == NULL)
160 		return (1);
161 
162 	sz = sizeof("pts/") - 1;
163 	if (strncmp(node, "pts/", sz) == 0 && node[sz] != '\0') {
164 		/*
165 		 * Linux checks major and minors of the slave device
166 		 * to make sure it's a pty device, so let's make him
167 		 * believe it is.
168 		 */
169 		devno = strtoul(node + sz, NULL, 10);
170 		*major = 136 + (devno / 256);
171 		*minor = devno % 256;
172 		return (0);
173 	}
174 
175 	sz = sizeof("dri/card") - 1;
176 	if (strncmp(node, "dri/card", sz) == 0 && node[sz] != '\0') {
177 		devno = strtoul(node + sz, NULL, 10);
178 		*major = 226 + (devno / 256);
179 		*minor = devno % 256;
180 		return (0);
181 	}
182 	sz = sizeof("dri/controlD") - 1;
183 	if (strncmp(node, "dri/controlD", sz) == 0 && node[sz] != '\0') {
184 		devno = strtoul(node + sz, NULL, 10);
185 		*major = 226 + (devno / 256);
186 		*minor = devno % 256;
187 		return (0);
188 	}
189 	sz = sizeof("dri/renderD") - 1;
190 	if (strncmp(node, "dri/renderD", sz) == 0 && node[sz] != '\0') {
191 		devno = strtoul(node + sz, NULL, 10);
192 		*major = 226 + (devno / 256);
193 		*minor = devno % 256;
194 		return (0);
195 	}
196 	sz = sizeof("drm/") - 1;
197 	if (strncmp(node, "drm/", sz) == 0 && node[sz] != '\0') {
198 		devno = strtoul(node + sz, NULL, 10);
199 		*major = 226 + (devno / 256);
200 		*minor = devno % 256;
201 		return (0);
202 	}
203 
204 	TAILQ_FOREACH(de, &devices, list) {
205 		if (strcmp(node, de->entry.bsd_device_name) == 0) {
206 			*major = de->entry.linux_major;
207 			*minor = de->entry.linux_minor;
208 			return (0);
209 		}
210 	}
211 
212 	return (1);
213 }
214 
215 int
216 linux_vn_get_major_minor(const struct vnode *vp, int *major, int *minor)
217 {
218 	int error;
219 
220 	if (vp->v_type != VCHR)
221 		return (ENOTBLK);
222 	dev_lock();
223 	if (vp->v_rdev == NULL) {
224 		dev_unlock();
225 		return (ENXIO);
226 	}
227 	error = linux_driver_get_major_minor(devtoname(vp->v_rdev),
228 	    major, minor);
229 	dev_unlock();
230 	return (error);
231 }
232 
233 void
234 translate_vnhook_major_minor(struct vnode *vp, struct stat *sb)
235 {
236 	int major, minor;
237 
238 	if (vn_isdisk(vp)) {
239 		sb->st_mode &= ~S_IFMT;
240 		sb->st_mode |= S_IFBLK;
241 	}
242 
243 	/*
244 	 * Return the same st_dev for every devfs instance.  The reason
245 	 * for this is to work around an idiosyncrasy of glibc getttynam()
246 	 * implementation: it checks whether st_dev returned for fd 0
247 	 * is the same as st_dev returned for the target of /proc/self/fd/0
248 	 * symlink, and with linux chroots having their own devfs instance,
249 	 * the check will fail if you chroot into it.
250 	 */
251 	if (rootdevmp != NULL && vp->v_mount->mnt_vfc == rootdevmp->mnt_vfc)
252 		sb->st_dev = rootdevmp->mnt_stat.f_fsid.val[0];
253 
254 	if (linux_vn_get_major_minor(vp, &major, &minor) == 0)
255 		sb->st_rdev = makedev(major, minor);
256 }
257 
258 char *
259 linux_get_char_devices(void)
260 {
261 	struct device_element *de;
262 	char *temp, *string, *last;
263 	char formated[256];
264 	int current_size = 0, string_size = 1024;
265 
266 	string = malloc(string_size, M_LINUX, M_WAITOK);
267 	string[0] = '\000';
268 	last = "";
269 	TAILQ_FOREACH(de, &devices, list) {
270 		if (!de->entry.linux_char_device)
271 			continue;
272 		temp = string;
273 		if (strcmp(last, de->entry.bsd_driver_name) != 0) {
274 			last = de->entry.bsd_driver_name;
275 
276 			snprintf(formated, sizeof(formated), "%3d %s\n",
277 				 de->entry.linux_major,
278 				 de->entry.linux_device_name);
279 			if (strlen(formated) + current_size
280 			    >= string_size) {
281 				string_size *= 2;
282 				string = malloc(string_size,
283 				    M_LINUX, M_WAITOK);
284 				bcopy(temp, string, current_size);
285 				free(temp, M_LINUX);
286 			}
287 			strcat(string, formated);
288 			current_size = strlen(string);
289 		}
290 	}
291 
292 	return (string);
293 }
294 
295 void
296 linux_free_get_char_devices(char *string)
297 {
298 
299 	free(string, M_LINUX);
300 }
301 
302 static int linux_major_starting = 200;
303 
304 int
305 linux_device_register_handler(struct linux_device_handler *d)
306 {
307 	struct device_element *de;
308 
309 	if (d == NULL)
310 		return (EINVAL);
311 
312 	de = malloc(sizeof(*de), M_LINUX, M_WAITOK);
313 	if (d->linux_major < 0) {
314 		d->linux_major = linux_major_starting++;
315 	}
316 	bcopy(d, &de->entry, sizeof(*d));
317 
318 	/* Add the element to the list, sorted on span. */
319 	TAILQ_INSERT_TAIL(&devices, de, list);
320 
321 	return (0);
322 }
323 
324 int
325 linux_device_unregister_handler(struct linux_device_handler *d)
326 {
327 	struct device_element *de;
328 
329 	if (d == NULL)
330 		return (EINVAL);
331 
332 	TAILQ_FOREACH(de, &devices, list) {
333 		if (bcmp(d, &de->entry, sizeof(*d)) == 0) {
334 			TAILQ_REMOVE(&devices, de, list);
335 			free(de, M_LINUX);
336 
337 			return (0);
338 		}
339 	}
340 
341 	return (EINVAL);
342 }
343