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 <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 */
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
coda_psdev_poll(struct file * file,poll_table * wait)64 static 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
coda_psdev_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)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
coda_psdev_write(struct file * file,const char __user * buf,size_t nbytes,loff_t * off)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 if (!outp->fh)
193 return -EBADF;
194 }
195 }
196
197 wake_up(&req->uc_sleep);
198 out:
199 return(count ? count : retval);
200 }
201
202 /*
203 * Read a message from the kernel to Venus
204 */
205
coda_psdev_read(struct file * file,char __user * buf,size_t nbytes,loff_t * off)206 static ssize_t coda_psdev_read(struct file * file, char __user * buf,
207 size_t nbytes, loff_t *off)
208 {
209 DECLARE_WAITQUEUE(wait, current);
210 struct venus_comm *vcp = (struct venus_comm *) file->private_data;
211 struct upc_req *req;
212 ssize_t retval = 0, count = 0;
213
214 if (nbytes == 0)
215 return 0;
216
217 mutex_lock(&vcp->vc_mutex);
218
219 add_wait_queue(&vcp->vc_waitq, &wait);
220 set_current_state(TASK_INTERRUPTIBLE);
221
222 while (list_empty(&vcp->vc_pending)) {
223 if (file->f_flags & O_NONBLOCK) {
224 retval = -EAGAIN;
225 break;
226 }
227 if (signal_pending(current)) {
228 retval = -ERESTARTSYS;
229 break;
230 }
231 mutex_unlock(&vcp->vc_mutex);
232 schedule();
233 mutex_lock(&vcp->vc_mutex);
234 }
235
236 set_current_state(TASK_RUNNING);
237 remove_wait_queue(&vcp->vc_waitq, &wait);
238
239 if (retval)
240 goto out;
241
242 req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain);
243 list_del(&req->uc_chain);
244
245 /* Move the input args into userspace */
246 count = req->uc_inSize;
247 if (nbytes < req->uc_inSize) {
248 pr_warn("%s: Venus read %ld bytes of %d in message\n",
249 __func__, (long)nbytes, req->uc_inSize);
250 count = nbytes;
251 }
252
253 if (copy_to_user(buf, req->uc_data, count))
254 retval = -EFAULT;
255
256 /* If request was not a signal, enqueue and don't free */
257 if (!(req->uc_flags & CODA_REQ_ASYNC)) {
258 req->uc_flags |= CODA_REQ_READ;
259 list_add_tail(&(req->uc_chain), &vcp->vc_processing);
260 goto out;
261 }
262
263 CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
264 kfree(req);
265 out:
266 mutex_unlock(&vcp->vc_mutex);
267 return (count ? count : retval);
268 }
269
coda_psdev_open(struct inode * inode,struct file * file)270 static int coda_psdev_open(struct inode * inode, struct file * file)
271 {
272 struct venus_comm *vcp;
273 int idx, err;
274
275 if (task_active_pid_ns(current) != &init_pid_ns)
276 return -EINVAL;
277
278 if (current_user_ns() != &init_user_ns)
279 return -EINVAL;
280
281 idx = iminor(inode);
282 if (idx < 0 || idx >= MAX_CODADEVS)
283 return -ENODEV;
284
285 err = -EBUSY;
286 vcp = &coda_comms[idx];
287 mutex_lock(&vcp->vc_mutex);
288
289 if (!vcp->vc_inuse) {
290 vcp->vc_inuse++;
291
292 INIT_LIST_HEAD(&vcp->vc_pending);
293 INIT_LIST_HEAD(&vcp->vc_processing);
294 init_waitqueue_head(&vcp->vc_waitq);
295 vcp->vc_sb = NULL;
296 vcp->vc_seq = 0;
297
298 file->private_data = vcp;
299 err = 0;
300 }
301
302 mutex_unlock(&vcp->vc_mutex);
303 return err;
304 }
305
306
coda_psdev_release(struct inode * inode,struct file * file)307 static int coda_psdev_release(struct inode * inode, struct file * file)
308 {
309 struct venus_comm *vcp = (struct venus_comm *) file->private_data;
310 struct upc_req *req, *tmp;
311
312 if (!vcp || !vcp->vc_inuse ) {
313 pr_warn("%s: Not open.\n", __func__);
314 return -1;
315 }
316
317 mutex_lock(&vcp->vc_mutex);
318
319 /* Wakeup clients so they can return. */
320 list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) {
321 list_del(&req->uc_chain);
322
323 /* Async requests need to be freed here */
324 if (req->uc_flags & CODA_REQ_ASYNC) {
325 CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
326 kfree(req);
327 continue;
328 }
329 req->uc_flags |= CODA_REQ_ABORT;
330 wake_up(&req->uc_sleep);
331 }
332
333 list_for_each_entry_safe(req, tmp, &vcp->vc_processing, uc_chain) {
334 list_del(&req->uc_chain);
335
336 req->uc_flags |= CODA_REQ_ABORT;
337 wake_up(&req->uc_sleep);
338 }
339
340 file->private_data = NULL;
341 vcp->vc_inuse--;
342 mutex_unlock(&vcp->vc_mutex);
343 return 0;
344 }
345
346
347 static const struct file_operations coda_psdev_fops = {
348 .owner = THIS_MODULE,
349 .read = coda_psdev_read,
350 .write = coda_psdev_write,
351 .poll = coda_psdev_poll,
352 .unlocked_ioctl = coda_psdev_ioctl,
353 .open = coda_psdev_open,
354 .release = coda_psdev_release,
355 .llseek = noop_llseek,
356 };
357
init_coda_psdev(void)358 static int init_coda_psdev(void)
359 {
360 int i, err = 0;
361 if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) {
362 pr_err("%s: unable to get major %d\n",
363 __func__, CODA_PSDEV_MAJOR);
364 return -EIO;
365 }
366 coda_psdev_class = class_create(THIS_MODULE, "coda");
367 if (IS_ERR(coda_psdev_class)) {
368 err = PTR_ERR(coda_psdev_class);
369 goto out_chrdev;
370 }
371 for (i = 0; i < MAX_CODADEVS; i++) {
372 mutex_init(&(&coda_comms[i])->vc_mutex);
373 device_create(coda_psdev_class, NULL,
374 MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i);
375 }
376 coda_sysctl_init();
377 goto out;
378
379 out_chrdev:
380 unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
381 out:
382 return err;
383 }
384
385 MODULE_AUTHOR("Jan Harkes, Peter J. Braam");
386 MODULE_DESCRIPTION("Coda Distributed File System VFS interface");
387 MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR);
388 MODULE_LICENSE("GPL");
389 MODULE_VERSION("6.6");
390
init_coda(void)391 static int __init init_coda(void)
392 {
393 int status;
394 int i;
395
396 status = coda_init_inodecache();
397 if (status)
398 goto out2;
399 status = init_coda_psdev();
400 if ( status ) {
401 pr_warn("Problem (%d) in init_coda_psdev\n", status);
402 goto out1;
403 }
404
405 status = register_filesystem(&coda_fs_type);
406 if (status) {
407 pr_warn("failed to register filesystem!\n");
408 goto out;
409 }
410 return 0;
411 out:
412 for (i = 0; i < MAX_CODADEVS; i++)
413 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
414 class_destroy(coda_psdev_class);
415 unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
416 coda_sysctl_clean();
417 out1:
418 coda_destroy_inodecache();
419 out2:
420 return status;
421 }
422
exit_coda(void)423 static void __exit exit_coda(void)
424 {
425 int err, i;
426
427 err = unregister_filesystem(&coda_fs_type);
428 if (err != 0)
429 pr_warn("failed to unregister filesystem\n");
430 for (i = 0; i < MAX_CODADEVS; i++)
431 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
432 class_destroy(coda_psdev_class);
433 unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
434 coda_sysctl_clean();
435 coda_destroy_inodecache();
436 }
437
438 module_init(init_coda);
439 module_exit(exit_coda);
440
441