xref: /openbmc/linux/fs/coda/psdev.c (revision d0e22329) 
1 /*
2  *      	An implementation of a loadable kernel mode driver providing
3  *		multiple kernel/user space bidirectional communications links.
4  *
5  * 		Author: 	Alan Cox <alan@lxorguk.ukuu.org.uk>
6  *
7  *		This program is free software; you can redistribute it and/or
8  *		modify it under the terms of the GNU General Public License
9  *		as published by the Free Software Foundation; either version
10  *		2 of the License, or (at your option) any later version.
11  *
12  *              Adapted to become the Linux 2.0 Coda pseudo device
13  *              Peter  Braam  <braam@maths.ox.ac.uk>
14  *              Michael Callahan <mjc@emmy.smith.edu>
15  *
16  *              Changes for Linux 2.1
17  *              Copyright (c) 1997 Carnegie-Mellon University
18  */
19 
20 #include <linux/module.h>
21 #include <linux/errno.h>
22 #include <linux/kernel.h>
23 #include <linux/major.h>
24 #include <linux/time.h>
25 #include <linux/sched/signal.h>
26 #include <linux/slab.h>
27 #include <linux/ioport.h>
28 #include <linux/fcntl.h>
29 #include <linux/delay.h>
30 #include <linux/skbuff.h>
31 #include <linux/proc_fs.h>
32 #include <linux/vmalloc.h>
33 #include <linux/fs.h>
34 #include <linux/file.h>
35 #include <linux/poll.h>
36 #include <linux/init.h>
37 #include <linux/list.h>
38 #include <linux/mutex.h>
39 #include <linux/device.h>
40 #include <linux/pid_namespace.h>
41 #include <asm/io.h>
42 #include <linux/poll.h>
43 #include <linux/uaccess.h>
44 
45 #include <linux/coda.h>
46 #include <linux/coda_psdev.h>
47 
48 #include "coda_linux.h"
49 
50 #include "coda_int.h"
51 
52 /* statistics */
53 int           coda_hard;         /* allows signals during upcalls */
54 unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */
55 
56 
57 struct venus_comm coda_comms[MAX_CODADEVS];
58 static struct class *coda_psdev_class;
59 
60 /*
61  * Device operations
62  */
63 
64 static __poll_t coda_psdev_poll(struct file *file, poll_table * wait)
65 {
66         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
67 	__poll_t mask = EPOLLOUT | EPOLLWRNORM;
68 
69 	poll_wait(file, &vcp->vc_waitq, wait);
70 	mutex_lock(&vcp->vc_mutex);
71 	if (!list_empty(&vcp->vc_pending))
72                 mask |= EPOLLIN | EPOLLRDNORM;
73 	mutex_unlock(&vcp->vc_mutex);
74 
75 	return mask;
76 }
77 
78 static long coda_psdev_ioctl(struct file * filp, unsigned int cmd, unsigned long arg)
79 {
80 	unsigned int data;
81 
82 	switch(cmd) {
83 	case CIOC_KERNEL_VERSION:
84 		data = CODA_KERNEL_VERSION;
85 		return put_user(data, (int __user *) arg);
86 	default:
87 		return -ENOTTY;
88 	}
89 
90 	return 0;
91 }
92 
93 /*
94  *	Receive a message written by Venus to the psdev
95  */
96 
97 static ssize_t coda_psdev_write(struct file *file, const char __user *buf,
98 				size_t nbytes, loff_t *off)
99 {
100         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
101         struct upc_req *req = NULL;
102         struct upc_req *tmp;
103 	struct list_head *lh;
104 	struct coda_in_hdr hdr;
105 	ssize_t retval = 0, count = 0;
106 	int error;
107 
108         /* Peek at the opcode, uniquefier */
109 	if (copy_from_user(&hdr, buf, 2 * sizeof(u_long)))
110 	        return -EFAULT;
111 
112         if (DOWNCALL(hdr.opcode)) {
113 		union outputArgs *dcbuf;
114 		int size = sizeof(*dcbuf);
115 
116 		if  ( nbytes < sizeof(struct coda_out_hdr) ) {
117 			pr_warn("coda_downcall opc %d uniq %d, not enough!\n",
118 				hdr.opcode, hdr.unique);
119 			count = nbytes;
120 			goto out;
121 		}
122 		if ( nbytes > size ) {
123 			pr_warn("downcall opc %d, uniq %d, too much!",
124 				hdr.opcode, hdr.unique);
125 		        nbytes = size;
126 		}
127 		CODA_ALLOC(dcbuf, union outputArgs *, nbytes);
128 		if (copy_from_user(dcbuf, buf, nbytes)) {
129 			CODA_FREE(dcbuf, nbytes);
130 			retval = -EFAULT;
131 			goto out;
132 		}
133 
134 		/* what downcall errors does Venus handle ? */
135 		error = coda_downcall(vcp, hdr.opcode, dcbuf);
136 
137 		CODA_FREE(dcbuf, nbytes);
138 		if (error) {
139 			pr_warn("%s: coda_downcall error: %d\n",
140 				__func__, error);
141 			retval = error;
142 			goto out;
143 		}
144 		count = nbytes;
145 		goto out;
146 	}
147 
148 	/* Look for the message on the processing queue. */
149 	mutex_lock(&vcp->vc_mutex);
150 	list_for_each(lh, &vcp->vc_processing) {
151 		tmp = list_entry(lh, struct upc_req , uc_chain);
152 		if (tmp->uc_unique == hdr.unique) {
153 			req = tmp;
154 			list_del(&req->uc_chain);
155 			break;
156 		}
157 	}
158 	mutex_unlock(&vcp->vc_mutex);
159 
160 	if (!req) {
161 		pr_warn("%s: msg (%d, %d) not found\n",
162 			__func__, hdr.opcode, hdr.unique);
163 		retval = -ESRCH;
164 		goto out;
165 	}
166 
167         /* move data into response buffer. */
168 	if (req->uc_outSize < nbytes) {
169 		pr_warn("%s: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d.\n",
170 			__func__, req->uc_outSize, (long)nbytes,
171 			hdr.opcode, hdr.unique);
172 		nbytes = req->uc_outSize; /* don't have more space! */
173 	}
174         if (copy_from_user(req->uc_data, buf, nbytes)) {
175 		req->uc_flags |= CODA_REQ_ABORT;
176 		wake_up(&req->uc_sleep);
177 		retval = -EFAULT;
178 		goto out;
179 	}
180 
181 	/* adjust outsize. is this useful ?? */
182 	req->uc_outSize = nbytes;
183 	req->uc_flags |= CODA_REQ_WRITE;
184 	count = nbytes;
185 
186 	/* Convert filedescriptor into a file handle */
187 	if (req->uc_opcode == CODA_OPEN_BY_FD) {
188 		struct coda_open_by_fd_out *outp =
189 			(struct coda_open_by_fd_out *)req->uc_data;
190 		if (!outp->oh.result)
191 			outp->fh = fget(outp->fd);
192 	}
193 
194         wake_up(&req->uc_sleep);
195 out:
196         return(count ? count : retval);
197 }
198 
199 /*
200  *	Read a message from the kernel to Venus
201  */
202 
203 static ssize_t coda_psdev_read(struct file * file, char __user * buf,
204 			       size_t nbytes, loff_t *off)
205 {
206 	DECLARE_WAITQUEUE(wait, current);
207         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
208         struct upc_req *req;
209 	ssize_t retval = 0, count = 0;
210 
211 	if (nbytes == 0)
212 		return 0;
213 
214 	mutex_lock(&vcp->vc_mutex);
215 
216 	add_wait_queue(&vcp->vc_waitq, &wait);
217 	set_current_state(TASK_INTERRUPTIBLE);
218 
219 	while (list_empty(&vcp->vc_pending)) {
220 		if (file->f_flags & O_NONBLOCK) {
221 			retval = -EAGAIN;
222 			break;
223 		}
224 		if (signal_pending(current)) {
225 			retval = -ERESTARTSYS;
226 			break;
227 		}
228 		mutex_unlock(&vcp->vc_mutex);
229 		schedule();
230 		mutex_lock(&vcp->vc_mutex);
231 	}
232 
233 	set_current_state(TASK_RUNNING);
234 	remove_wait_queue(&vcp->vc_waitq, &wait);
235 
236 	if (retval)
237 		goto out;
238 
239 	req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain);
240 	list_del(&req->uc_chain);
241 
242 	/* Move the input args into userspace */
243 	count = req->uc_inSize;
244 	if (nbytes < req->uc_inSize) {
245 		pr_warn("%s: Venus read %ld bytes of %d in message\n",
246 			__func__, (long)nbytes, req->uc_inSize);
247 		count = nbytes;
248         }
249 
250 	if (copy_to_user(buf, req->uc_data, count))
251 	        retval = -EFAULT;
252 
253 	/* If request was not a signal, enqueue and don't free */
254 	if (!(req->uc_flags & CODA_REQ_ASYNC)) {
255 		req->uc_flags |= CODA_REQ_READ;
256 		list_add_tail(&(req->uc_chain), &vcp->vc_processing);
257 		goto out;
258 	}
259 
260 	CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
261 	kfree(req);
262 out:
263 	mutex_unlock(&vcp->vc_mutex);
264 	return (count ? count : retval);
265 }
266 
267 static int coda_psdev_open(struct inode * inode, struct file * file)
268 {
269 	struct venus_comm *vcp;
270 	int idx, err;
271 
272 	if (task_active_pid_ns(current) != &init_pid_ns)
273 		return -EINVAL;
274 
275 	if (current_user_ns() != &init_user_ns)
276 		return -EINVAL;
277 
278 	idx = iminor(inode);
279 	if (idx < 0 || idx >= MAX_CODADEVS)
280 		return -ENODEV;
281 
282 	err = -EBUSY;
283 	vcp = &coda_comms[idx];
284 	mutex_lock(&vcp->vc_mutex);
285 
286 	if (!vcp->vc_inuse) {
287 		vcp->vc_inuse++;
288 
289 		INIT_LIST_HEAD(&vcp->vc_pending);
290 		INIT_LIST_HEAD(&vcp->vc_processing);
291 		init_waitqueue_head(&vcp->vc_waitq);
292 		vcp->vc_sb = NULL;
293 		vcp->vc_seq = 0;
294 
295 		file->private_data = vcp;
296 		err = 0;
297 	}
298 
299 	mutex_unlock(&vcp->vc_mutex);
300 	return err;
301 }
302 
303 
304 static int coda_psdev_release(struct inode * inode, struct file * file)
305 {
306 	struct venus_comm *vcp = (struct venus_comm *) file->private_data;
307 	struct upc_req *req, *tmp;
308 
309 	if (!vcp || !vcp->vc_inuse ) {
310 		pr_warn("%s: Not open.\n", __func__);
311 		return -1;
312 	}
313 
314 	mutex_lock(&vcp->vc_mutex);
315 
316 	/* Wakeup clients so they can return. */
317 	list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) {
318 		list_del(&req->uc_chain);
319 
320 		/* Async requests need to be freed here */
321 		if (req->uc_flags & CODA_REQ_ASYNC) {
322 			CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
323 			kfree(req);
324 			continue;
325 		}
326 		req->uc_flags |= CODA_REQ_ABORT;
327 		wake_up(&req->uc_sleep);
328 	}
329 
330 	list_for_each_entry_safe(req, tmp, &vcp->vc_processing, uc_chain) {
331 		list_del(&req->uc_chain);
332 
333 		req->uc_flags |= CODA_REQ_ABORT;
334 		wake_up(&req->uc_sleep);
335 	}
336 
337 	file->private_data = NULL;
338 	vcp->vc_inuse--;
339 	mutex_unlock(&vcp->vc_mutex);
340 	return 0;
341 }
342 
343 
344 static const struct file_operations coda_psdev_fops = {
345 	.owner		= THIS_MODULE,
346 	.read		= coda_psdev_read,
347 	.write		= coda_psdev_write,
348 	.poll		= coda_psdev_poll,
349 	.unlocked_ioctl	= coda_psdev_ioctl,
350 	.open		= coda_psdev_open,
351 	.release	= coda_psdev_release,
352 	.llseek		= noop_llseek,
353 };
354 
355 static int init_coda_psdev(void)
356 {
357 	int i, err = 0;
358 	if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) {
359 		pr_err("%s: unable to get major %d\n",
360 		       __func__, CODA_PSDEV_MAJOR);
361               return -EIO;
362 	}
363 	coda_psdev_class = class_create(THIS_MODULE, "coda");
364 	if (IS_ERR(coda_psdev_class)) {
365 		err = PTR_ERR(coda_psdev_class);
366 		goto out_chrdev;
367 	}
368 	for (i = 0; i < MAX_CODADEVS; i++) {
369 		mutex_init(&(&coda_comms[i])->vc_mutex);
370 		device_create(coda_psdev_class, NULL,
371 			      MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i);
372 	}
373 	coda_sysctl_init();
374 	goto out;
375 
376 out_chrdev:
377 	unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
378 out:
379 	return err;
380 }
381 
382 MODULE_AUTHOR("Jan Harkes, Peter J. Braam");
383 MODULE_DESCRIPTION("Coda Distributed File System VFS interface");
384 MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR);
385 MODULE_LICENSE("GPL");
386 MODULE_VERSION("6.6");
387 
388 static int __init init_coda(void)
389 {
390 	int status;
391 	int i;
392 
393 	status = coda_init_inodecache();
394 	if (status)
395 		goto out2;
396 	status = init_coda_psdev();
397 	if ( status ) {
398 		pr_warn("Problem (%d) in init_coda_psdev\n", status);
399 		goto out1;
400 	}
401 
402 	status = register_filesystem(&coda_fs_type);
403 	if (status) {
404 		pr_warn("failed to register filesystem!\n");
405 		goto out;
406 	}
407 	return 0;
408 out:
409 	for (i = 0; i < MAX_CODADEVS; i++)
410 		device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
411 	class_destroy(coda_psdev_class);
412 	unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
413 	coda_sysctl_clean();
414 out1:
415 	coda_destroy_inodecache();
416 out2:
417 	return status;
418 }
419 
420 static void __exit exit_coda(void)
421 {
422         int err, i;
423 
424 	err = unregister_filesystem(&coda_fs_type);
425 	if (err != 0)
426 		pr_warn("failed to unregister filesystem\n");
427 	for (i = 0; i < MAX_CODADEVS; i++)
428 		device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
429 	class_destroy(coda_psdev_class);
430 	unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
431 	coda_sysctl_clean();
432 	coda_destroy_inodecache();
433 }
434 
435 module_init(init_coda);
436 module_exit(exit_coda);
437 
438