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.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 <asm/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 */
53int           coda_hard;         /* allows signals during upcalls */
54unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */
55
56
57struct venus_comm coda_comms[MAX_CODADEVS];
58static struct class *coda_psdev_class;
59
60/*
61 * Device operations
62 */
63
64static unsigned int coda_psdev_poll(struct file *file, poll_table * wait)
65{
66        struct venus_comm *vcp = (struct venus_comm *) file->private_data;
67	unsigned int mask = POLLOUT | POLLWRNORM;
68
69	poll_wait(file, &vcp->vc_waitq, wait);
70	mutex_lock(&vcp->vc_mutex);
71	if (!list_empty(&vcp->vc_pending))
72                mask |= POLLIN | POLLRDNORM;
73	mutex_unlock(&vcp->vc_mutex);
74
75	return mask;
76}
77
78static 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
97static 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);
195out:
196        return(count ? count : retval);
197}
198
199/*
200 *	Read a message from the kernel to Venus
201 */
202
203static 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);
262out:
263	mutex_unlock(&vcp->vc_mutex);
264	return (count ? count : retval);
265}
266
267static 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
304static 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
344static 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
355static 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
376out_chrdev:
377	unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
378out:
379	return err;
380}
381
382MODULE_AUTHOR("Jan Harkes, Peter J. Braam");
383MODULE_DESCRIPTION("Coda Distributed File System VFS interface");
384MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR);
385MODULE_LICENSE("GPL");
386MODULE_VERSION("6.6");
387
388static 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;
408out:
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();
414out1:
415	coda_destroy_inodecache();
416out2:
417	return status;
418}
419
420static 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
435module_init(init_coda);
436module_exit(exit_coda);
437
438