xref: /openbmc/linux/fs/coda/psdev.c (revision 8f762fe5) 
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/uaccess.h>
43 
44 #include <linux/coda.h>
45 #include <linux/coda_psdev.h>
46 
47 #include "coda_linux.h"
48 
49 #include "coda_int.h"
50 
51 /* statistics */
52 int           coda_hard;         /* allows signals during upcalls */
53 unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */
54 
55 
56 struct venus_comm coda_comms[MAX_CODADEVS];
57 static struct class *coda_psdev_class;
58 
59 /*
60  * Device operations
61  */
62 
63 static __poll_t coda_psdev_poll(struct file *file, poll_table * wait)
64 {
65         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
66 	__poll_t mask = EPOLLOUT | EPOLLWRNORM;
67 
68 	poll_wait(file, &vcp->vc_waitq, wait);
69 	mutex_lock(&vcp->vc_mutex);
70 	if (!list_empty(&vcp->vc_pending))
71                 mask |= EPOLLIN | EPOLLRDNORM;
72 	mutex_unlock(&vcp->vc_mutex);
73 
74 	return mask;
75 }
76 
77 static long coda_psdev_ioctl(struct file * filp, unsigned int cmd, unsigned long arg)
78 {
79 	unsigned int data;
80 
81 	switch(cmd) {
82 	case CIOC_KERNEL_VERSION:
83 		data = CODA_KERNEL_VERSION;
84 		return put_user(data, (int __user *) arg);
85 	default:
86 		return -ENOTTY;
87 	}
88 
89 	return 0;
90 }
91 
92 /*
93  *	Receive a message written by Venus to the psdev
94  */
95 
96 static ssize_t coda_psdev_write(struct file *file, const char __user *buf,
97 				size_t nbytes, loff_t *off)
98 {
99         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
100         struct upc_req *req = NULL;
101         struct upc_req *tmp;
102 	struct list_head *lh;
103 	struct coda_in_hdr hdr;
104 	ssize_t retval = 0, count = 0;
105 	int error;
106 
107         /* Peek at the opcode, uniquefier */
108 	if (copy_from_user(&hdr, buf, 2 * sizeof(u_long)))
109 	        return -EFAULT;
110 
111         if (DOWNCALL(hdr.opcode)) {
112 		union outputArgs *dcbuf;
113 		int size = sizeof(*dcbuf);
114 
115 		if  ( nbytes < sizeof(struct coda_out_hdr) ) {
116 			pr_warn("coda_downcall opc %d uniq %d, not enough!\n",
117 				hdr.opcode, hdr.unique);
118 			count = nbytes;
119 			goto out;
120 		}
121 		if ( nbytes > size ) {
122 			pr_warn("downcall opc %d, uniq %d, too much!",
123 				hdr.opcode, hdr.unique);
124 		        nbytes = size;
125 		}
126 		CODA_ALLOC(dcbuf, union outputArgs *, nbytes);
127 		if (copy_from_user(dcbuf, buf, nbytes)) {
128 			CODA_FREE(dcbuf, nbytes);
129 			retval = -EFAULT;
130 			goto out;
131 		}
132 
133 		/* what downcall errors does Venus handle ? */
134 		error = coda_downcall(vcp, hdr.opcode, dcbuf);
135 
136 		CODA_FREE(dcbuf, nbytes);
137 		if (error) {
138 			pr_warn("%s: coda_downcall error: %d\n",
139 				__func__, error);
140 			retval = error;
141 			goto out;
142 		}
143 		count = nbytes;
144 		goto out;
145 	}
146 
147 	/* Look for the message on the processing queue. */
148 	mutex_lock(&vcp->vc_mutex);
149 	list_for_each(lh, &vcp->vc_processing) {
150 		tmp = list_entry(lh, struct upc_req , uc_chain);
151 		if (tmp->uc_unique == hdr.unique) {
152 			req = tmp;
153 			list_del(&req->uc_chain);
154 			break;
155 		}
156 	}
157 	mutex_unlock(&vcp->vc_mutex);
158 
159 	if (!req) {
160 		pr_warn("%s: msg (%d, %d) not found\n",
161 			__func__, hdr.opcode, hdr.unique);
162 		retval = -ESRCH;
163 		goto out;
164 	}
165 
166         /* move data into response buffer. */
167 	if (req->uc_outSize < nbytes) {
168 		pr_warn("%s: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d.\n",
169 			__func__, req->uc_outSize, (long)nbytes,
170 			hdr.opcode, hdr.unique);
171 		nbytes = req->uc_outSize; /* don't have more space! */
172 	}
173         if (copy_from_user(req->uc_data, buf, nbytes)) {
174 		req->uc_flags |= CODA_REQ_ABORT;
175 		wake_up(&req->uc_sleep);
176 		retval = -EFAULT;
177 		goto out;
178 	}
179 
180 	/* adjust outsize. is this useful ?? */
181 	req->uc_outSize = nbytes;
182 	req->uc_flags |= CODA_REQ_WRITE;
183 	count = nbytes;
184 
185 	/* Convert filedescriptor into a file handle */
186 	if (req->uc_opcode == CODA_OPEN_BY_FD) {
187 		struct coda_open_by_fd_out *outp =
188 			(struct coda_open_by_fd_out *)req->uc_data;
189 		if (!outp->oh.result)
190 			outp->fh = fget(outp->fd);
191 	}
192 
193         wake_up(&req->uc_sleep);
194 out:
195         return(count ? count : retval);
196 }
197 
198 /*
199  *	Read a message from the kernel to Venus
200  */
201 
202 static ssize_t coda_psdev_read(struct file * file, char __user * buf,
203 			       size_t nbytes, loff_t *off)
204 {
205 	DECLARE_WAITQUEUE(wait, current);
206         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
207         struct upc_req *req;
208 	ssize_t retval = 0, count = 0;
209 
210 	if (nbytes == 0)
211 		return 0;
212 
213 	mutex_lock(&vcp->vc_mutex);
214 
215 	add_wait_queue(&vcp->vc_waitq, &wait);
216 	set_current_state(TASK_INTERRUPTIBLE);
217 
218 	while (list_empty(&vcp->vc_pending)) {
219 		if (file->f_flags & O_NONBLOCK) {
220 			retval = -EAGAIN;
221 			break;
222 		}
223 		if (signal_pending(current)) {
224 			retval = -ERESTARTSYS;
225 			break;
226 		}
227 		mutex_unlock(&vcp->vc_mutex);
228 		schedule();
229 		mutex_lock(&vcp->vc_mutex);
230 	}
231 
232 	set_current_state(TASK_RUNNING);
233 	remove_wait_queue(&vcp->vc_waitq, &wait);
234 
235 	if (retval)
236 		goto out;
237 
238 	req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain);
239 	list_del(&req->uc_chain);
240 
241 	/* Move the input args into userspace */
242 	count = req->uc_inSize;
243 	if (nbytes < req->uc_inSize) {
244 		pr_warn("%s: Venus read %ld bytes of %d in message\n",
245 			__func__, (long)nbytes, req->uc_inSize);
246 		count = nbytes;
247         }
248 
249 	if (copy_to_user(buf, req->uc_data, count))
250 	        retval = -EFAULT;
251 
252 	/* If request was not a signal, enqueue and don't free */
253 	if (!(req->uc_flags & CODA_REQ_ASYNC)) {
254 		req->uc_flags |= CODA_REQ_READ;
255 		list_add_tail(&(req->uc_chain), &vcp->vc_processing);
256 		goto out;
257 	}
258 
259 	CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
260 	kfree(req);
261 out:
262 	mutex_unlock(&vcp->vc_mutex);
263 	return (count ? count : retval);
264 }
265 
266 static int coda_psdev_open(struct inode * inode, struct file * file)
267 {
268 	struct venus_comm *vcp;
269 	int idx, err;
270 
271 	if (task_active_pid_ns(current) != &init_pid_ns)
272 		return -EINVAL;
273 
274 	if (current_user_ns() != &init_user_ns)
275 		return -EINVAL;
276 
277 	idx = iminor(inode);
278 	if (idx < 0 || idx >= MAX_CODADEVS)
279 		return -ENODEV;
280 
281 	err = -EBUSY;
282 	vcp = &coda_comms[idx];
283 	mutex_lock(&vcp->vc_mutex);
284 
285 	if (!vcp->vc_inuse) {
286 		vcp->vc_inuse++;
287 
288 		INIT_LIST_HEAD(&vcp->vc_pending);
289 		INIT_LIST_HEAD(&vcp->vc_processing);
290 		init_waitqueue_head(&vcp->vc_waitq);
291 		vcp->vc_sb = NULL;
292 		vcp->vc_seq = 0;
293 
294 		file->private_data = vcp;
295 		err = 0;
296 	}
297 
298 	mutex_unlock(&vcp->vc_mutex);
299 	return err;
300 }
301 
302 
303 static int coda_psdev_release(struct inode * inode, struct file * file)
304 {
305 	struct venus_comm *vcp = (struct venus_comm *) file->private_data;
306 	struct upc_req *req, *tmp;
307 
308 	if (!vcp || !vcp->vc_inuse ) {
309 		pr_warn("%s: Not open.\n", __func__);
310 		return -1;
311 	}
312 
313 	mutex_lock(&vcp->vc_mutex);
314 
315 	/* Wakeup clients so they can return. */
316 	list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) {
317 		list_del(&req->uc_chain);
318 
319 		/* Async requests need to be freed here */
320 		if (req->uc_flags & CODA_REQ_ASYNC) {
321 			CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
322 			kfree(req);
323 			continue;
324 		}
325 		req->uc_flags |= CODA_REQ_ABORT;
326 		wake_up(&req->uc_sleep);
327 	}
328 
329 	list_for_each_entry_safe(req, tmp, &vcp->vc_processing, uc_chain) {
330 		list_del(&req->uc_chain);
331 
332 		req->uc_flags |= CODA_REQ_ABORT;
333 		wake_up(&req->uc_sleep);
334 	}
335 
336 	file->private_data = NULL;
337 	vcp->vc_inuse--;
338 	mutex_unlock(&vcp->vc_mutex);
339 	return 0;
340 }
341 
342 
343 static const struct file_operations coda_psdev_fops = {
344 	.owner		= THIS_MODULE,
345 	.read		= coda_psdev_read,
346 	.write		= coda_psdev_write,
347 	.poll		= coda_psdev_poll,
348 	.unlocked_ioctl	= coda_psdev_ioctl,
349 	.open		= coda_psdev_open,
350 	.release	= coda_psdev_release,
351 	.llseek		= noop_llseek,
352 };
353 
354 static int init_coda_psdev(void)
355 {
356 	int i, err = 0;
357 	if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) {
358 		pr_err("%s: unable to get major %d\n",
359 		       __func__, CODA_PSDEV_MAJOR);
360               return -EIO;
361 	}
362 	coda_psdev_class = class_create(THIS_MODULE, "coda");
363 	if (IS_ERR(coda_psdev_class)) {
364 		err = PTR_ERR(coda_psdev_class);
365 		goto out_chrdev;
366 	}
367 	for (i = 0; i < MAX_CODADEVS; i++) {
368 		mutex_init(&(&coda_comms[i])->vc_mutex);
369 		device_create(coda_psdev_class, NULL,
370 			      MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i);
371 	}
372 	coda_sysctl_init();
373 	goto out;
374 
375 out_chrdev:
376 	unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
377 out:
378 	return err;
379 }
380 
381 MODULE_AUTHOR("Jan Harkes, Peter J. Braam");
382 MODULE_DESCRIPTION("Coda Distributed File System VFS interface");
383 MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR);
384 MODULE_LICENSE("GPL");
385 MODULE_VERSION("6.6");
386 
387 static int __init init_coda(void)
388 {
389 	int status;
390 	int i;
391 
392 	status = coda_init_inodecache();
393 	if (status)
394 		goto out2;
395 	status = init_coda_psdev();
396 	if ( status ) {
397 		pr_warn("Problem (%d) in init_coda_psdev\n", status);
398 		goto out1;
399 	}
400 
401 	status = register_filesystem(&coda_fs_type);
402 	if (status) {
403 		pr_warn("failed to register filesystem!\n");
404 		goto out;
405 	}
406 	return 0;
407 out:
408 	for (i = 0; i < MAX_CODADEVS; i++)
409 		device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
410 	class_destroy(coda_psdev_class);
411 	unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
412 	coda_sysctl_clean();
413 out1:
414 	coda_destroy_inodecache();
415 out2:
416 	return status;
417 }
418 
419 static void __exit exit_coda(void)
420 {
421         int err, i;
422 
423 	err = unregister_filesystem(&coda_fs_type);
424 	if (err != 0)
425 		pr_warn("failed to unregister filesystem\n");
426 	for (i = 0; i < MAX_CODADEVS; i++)
427 		device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
428 	class_destroy(coda_psdev_class);
429 	unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
430 	coda_sysctl_clean();
431 	coda_destroy_inodecache();
432 }
433 
434 module_init(init_coda);
435 module_exit(exit_coda);
436 
437