1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * An implementation of a loadable kernel mode driver providing
4 * multiple kernel/user space bidirectional communications links.
5 *
6 * Author: Alan Cox <alan@lxorguk.ukuu.org.uk>
7 *
8 * Adapted to become the Linux 2.0 Coda pseudo device
9 * Peter Braam <braam@maths.ox.ac.uk>
10 * Michael Callahan <mjc@emmy.smith.edu>
11 *
12 * Changes for Linux 2.1
13 * Copyright (c) 1997 Carnegie-Mellon University
14 */
15
16 #include <linux/module.h>
17 #include <linux/errno.h>
18 #include <linux/kernel.h>
19 #include <linux/major.h>
20 #include <linux/time.h>
21 #include <linux/sched/signal.h>
22 #include <linux/slab.h>
23 #include <linux/ioport.h>
24 #include <linux/fcntl.h>
25 #include <linux/delay.h>
26 #include <linux/skbuff.h>
27 #include <linux/proc_fs.h>
28 #include <linux/vmalloc.h>
29 #include <linux/fs.h>
30 #include <linux/file.h>
31 #include <linux/poll.h>
32 #include <linux/init.h>
33 #include <linux/list.h>
34 #include <linux/mutex.h>
35 #include <linux/device.h>
36 #include <linux/pid_namespace.h>
37 #include <asm/io.h>
38 #include <linux/uaccess.h>
39
40 #include <linux/coda.h>
41 #include "coda_psdev.h"
42 #include "coda_linux.h"
43
44 #include "coda_int.h"
45
46 /* statistics */
47 int coda_hard; /* allows signals during upcalls */
48 unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */
49
50
51 struct venus_comm coda_comms[MAX_CODADEVS];
52 static struct class *coda_psdev_class;
53
54 /*
55 * Device operations
56 */
57
coda_psdev_poll(struct file * file,poll_table * wait)58 static __poll_t coda_psdev_poll(struct file *file, poll_table * wait)
59 {
60 struct venus_comm *vcp = (struct venus_comm *) file->private_data;
61 __poll_t mask = EPOLLOUT | EPOLLWRNORM;
62
63 poll_wait(file, &vcp->vc_waitq, wait);
64 mutex_lock(&vcp->vc_mutex);
65 if (!list_empty(&vcp->vc_pending))
66 mask |= EPOLLIN | EPOLLRDNORM;
67 mutex_unlock(&vcp->vc_mutex);
68
69 return mask;
70 }
71
coda_psdev_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)72 static long coda_psdev_ioctl(struct file * filp, unsigned int cmd, unsigned long arg)
73 {
74 unsigned int data;
75
76 switch(cmd) {
77 case CIOC_KERNEL_VERSION:
78 data = CODA_KERNEL_VERSION;
79 return put_user(data, (int __user *) arg);
80 default:
81 return -ENOTTY;
82 }
83
84 return 0;
85 }
86
87 /*
88 * Receive a message written by Venus to the psdev
89 */
90
coda_psdev_write(struct file * file,const char __user * buf,size_t nbytes,loff_t * off)91 static ssize_t coda_psdev_write(struct file *file, const char __user *buf,
92 size_t nbytes, loff_t *off)
93 {
94 struct venus_comm *vcp = (struct venus_comm *) file->private_data;
95 struct upc_req *req = NULL;
96 struct upc_req *tmp;
97 struct list_head *lh;
98 struct coda_in_hdr hdr;
99 ssize_t retval = 0, count = 0;
100 int error;
101
102 /* make sure there is enough to copy out the (opcode, unique) values */
103 if (nbytes < (2 * sizeof(u_int32_t)))
104 return -EINVAL;
105
106 /* Peek at the opcode, uniquefier */
107 if (copy_from_user(&hdr, buf, 2 * sizeof(u_int32_t)))
108 return -EFAULT;
109
110 if (DOWNCALL(hdr.opcode)) {
111 union outputArgs *dcbuf;
112 int size = sizeof(*dcbuf);
113
114 if ( nbytes < sizeof(struct coda_out_hdr) ) {
115 pr_warn("coda_downcall opc %d uniq %d, not enough!\n",
116 hdr.opcode, hdr.unique);
117 count = nbytes;
118 goto out;
119 }
120 if ( nbytes > size ) {
121 pr_warn("downcall opc %d, uniq %d, too much!",
122 hdr.opcode, hdr.unique);
123 nbytes = size;
124 }
125 dcbuf = kvmalloc(nbytes, GFP_KERNEL);
126 if (!dcbuf) {
127 retval = -ENOMEM;
128 goto out;
129 }
130 if (copy_from_user(dcbuf, buf, nbytes)) {
131 kvfree(dcbuf);
132 retval = -EFAULT;
133 goto out;
134 }
135
136 /* what downcall errors does Venus handle ? */
137 error = coda_downcall(vcp, hdr.opcode, dcbuf, nbytes);
138
139 kvfree(dcbuf);
140 if (error) {
141 pr_warn("%s: coda_downcall error: %d\n",
142 __func__, error);
143 retval = error;
144 goto out;
145 }
146 count = nbytes;
147 goto out;
148 }
149
150 /* Look for the message on the processing queue. */
151 mutex_lock(&vcp->vc_mutex);
152 list_for_each(lh, &vcp->vc_processing) {
153 tmp = list_entry(lh, struct upc_req , uc_chain);
154 if (tmp->uc_unique == hdr.unique) {
155 req = tmp;
156 list_del(&req->uc_chain);
157 break;
158 }
159 }
160 mutex_unlock(&vcp->vc_mutex);
161
162 if (!req) {
163 pr_warn("%s: msg (%d, %d) not found\n",
164 __func__, hdr.opcode, hdr.unique);
165 retval = -ESRCH;
166 goto out;
167 }
168
169 /* move data into response buffer. */
170 if (req->uc_outSize < nbytes) {
171 pr_warn("%s: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d.\n",
172 __func__, req->uc_outSize, (long)nbytes,
173 hdr.opcode, hdr.unique);
174 nbytes = req->uc_outSize; /* don't have more space! */
175 }
176 if (copy_from_user(req->uc_data, buf, nbytes)) {
177 req->uc_flags |= CODA_REQ_ABORT;
178 wake_up(&req->uc_sleep);
179 retval = -EFAULT;
180 goto out;
181 }
182
183 /* adjust outsize. is this useful ?? */
184 req->uc_outSize = nbytes;
185 req->uc_flags |= CODA_REQ_WRITE;
186 count = nbytes;
187
188 /* Convert filedescriptor into a file handle */
189 if (req->uc_opcode == CODA_OPEN_BY_FD) {
190 struct coda_open_by_fd_out *outp =
191 (struct coda_open_by_fd_out *)req->uc_data;
192 if (!outp->oh.result) {
193 outp->fh = fget(outp->fd);
194 if (!outp->fh)
195 return -EBADF;
196 }
197 }
198
199 wake_up(&req->uc_sleep);
200 out:
201 return(count ? count : retval);
202 }
203
204 /*
205 * Read a message from the kernel to Venus
206 */
207
coda_psdev_read(struct file * file,char __user * buf,size_t nbytes,loff_t * off)208 static ssize_t coda_psdev_read(struct file * file, char __user * buf,
209 size_t nbytes, loff_t *off)
210 {
211 DECLARE_WAITQUEUE(wait, current);
212 struct venus_comm *vcp = (struct venus_comm *) file->private_data;
213 struct upc_req *req;
214 ssize_t retval = 0, count = 0;
215
216 if (nbytes == 0)
217 return 0;
218
219 mutex_lock(&vcp->vc_mutex);
220
221 add_wait_queue(&vcp->vc_waitq, &wait);
222 set_current_state(TASK_INTERRUPTIBLE);
223
224 while (list_empty(&vcp->vc_pending)) {
225 if (file->f_flags & O_NONBLOCK) {
226 retval = -EAGAIN;
227 break;
228 }
229 if (signal_pending(current)) {
230 retval = -ERESTARTSYS;
231 break;
232 }
233 mutex_unlock(&vcp->vc_mutex);
234 schedule();
235 mutex_lock(&vcp->vc_mutex);
236 }
237
238 set_current_state(TASK_RUNNING);
239 remove_wait_queue(&vcp->vc_waitq, &wait);
240
241 if (retval)
242 goto out;
243
244 req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain);
245 list_del(&req->uc_chain);
246
247 /* Move the input args into userspace */
248 count = req->uc_inSize;
249 if (nbytes < req->uc_inSize) {
250 pr_warn("%s: Venus read %ld bytes of %d in message\n",
251 __func__, (long)nbytes, req->uc_inSize);
252 count = nbytes;
253 }
254
255 if (copy_to_user(buf, req->uc_data, count))
256 retval = -EFAULT;
257
258 /* If request was not a signal, enqueue and don't free */
259 if (!(req->uc_flags & CODA_REQ_ASYNC)) {
260 req->uc_flags |= CODA_REQ_READ;
261 list_add_tail(&(req->uc_chain), &vcp->vc_processing);
262 goto out;
263 }
264
265 kvfree(req->uc_data);
266 kfree(req);
267 out:
268 mutex_unlock(&vcp->vc_mutex);
269 return (count ? count : retval);
270 }
271
coda_psdev_open(struct inode * inode,struct file * file)272 static int coda_psdev_open(struct inode * inode, struct file * file)
273 {
274 struct venus_comm *vcp;
275 int idx, err;
276
277 if (task_active_pid_ns(current) != &init_pid_ns)
278 return -EINVAL;
279
280 if (current_user_ns() != &init_user_ns)
281 return -EINVAL;
282
283 idx = iminor(inode);
284 if (idx < 0 || idx >= MAX_CODADEVS)
285 return -ENODEV;
286
287 err = -EBUSY;
288 vcp = &coda_comms[idx];
289 mutex_lock(&vcp->vc_mutex);
290
291 if (!vcp->vc_inuse) {
292 vcp->vc_inuse++;
293
294 INIT_LIST_HEAD(&vcp->vc_pending);
295 INIT_LIST_HEAD(&vcp->vc_processing);
296 init_waitqueue_head(&vcp->vc_waitq);
297 vcp->vc_sb = NULL;
298 vcp->vc_seq = 0;
299
300 file->private_data = vcp;
301 err = 0;
302 }
303
304 mutex_unlock(&vcp->vc_mutex);
305 return err;
306 }
307
308
coda_psdev_release(struct inode * inode,struct file * file)309 static int coda_psdev_release(struct inode * inode, struct file * file)
310 {
311 struct venus_comm *vcp = (struct venus_comm *) file->private_data;
312 struct upc_req *req, *tmp;
313
314 if (!vcp || !vcp->vc_inuse ) {
315 pr_warn("%s: Not open.\n", __func__);
316 return -1;
317 }
318
319 mutex_lock(&vcp->vc_mutex);
320
321 /* Wakeup clients so they can return. */
322 list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) {
323 list_del(&req->uc_chain);
324
325 /* Async requests need to be freed here */
326 if (req->uc_flags & CODA_REQ_ASYNC) {
327 kvfree(req->uc_data);
328 kfree(req);
329 continue;
330 }
331 req->uc_flags |= CODA_REQ_ABORT;
332 wake_up(&req->uc_sleep);
333 }
334
335 list_for_each_entry_safe(req, tmp, &vcp->vc_processing, uc_chain) {
336 list_del(&req->uc_chain);
337
338 req->uc_flags |= CODA_REQ_ABORT;
339 wake_up(&req->uc_sleep);
340 }
341
342 file->private_data = NULL;
343 vcp->vc_inuse--;
344 mutex_unlock(&vcp->vc_mutex);
345 return 0;
346 }
347
348
349 static const struct file_operations coda_psdev_fops = {
350 .owner = THIS_MODULE,
351 .read = coda_psdev_read,
352 .write = coda_psdev_write,
353 .poll = coda_psdev_poll,
354 .unlocked_ioctl = coda_psdev_ioctl,
355 .open = coda_psdev_open,
356 .release = coda_psdev_release,
357 .llseek = noop_llseek,
358 };
359
init_coda_psdev(void)360 static int __init init_coda_psdev(void)
361 {
362 int i, err = 0;
363 if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) {
364 pr_err("%s: unable to get major %d\n",
365 __func__, CODA_PSDEV_MAJOR);
366 return -EIO;
367 }
368 coda_psdev_class = class_create(THIS_MODULE, "coda");
369 if (IS_ERR(coda_psdev_class)) {
370 err = PTR_ERR(coda_psdev_class);
371 goto out_chrdev;
372 }
373 for (i = 0; i < MAX_CODADEVS; i++) {
374 mutex_init(&(&coda_comms[i])->vc_mutex);
375 device_create(coda_psdev_class, NULL,
376 MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i);
377 }
378 coda_sysctl_init();
379 goto out;
380
381 out_chrdev:
382 unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
383 out:
384 return err;
385 }
386
387 MODULE_AUTHOR("Jan Harkes, Peter J. Braam");
388 MODULE_DESCRIPTION("Coda Distributed File System VFS interface");
389 MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR);
390 MODULE_LICENSE("GPL");
391 MODULE_VERSION("7.0");
392
init_coda(void)393 static int __init init_coda(void)
394 {
395 int status;
396 int i;
397
398 status = coda_init_inodecache();
399 if (status)
400 goto out2;
401 status = init_coda_psdev();
402 if ( status ) {
403 pr_warn("Problem (%d) in init_coda_psdev\n", status);
404 goto out1;
405 }
406
407 status = register_filesystem(&coda_fs_type);
408 if (status) {
409 pr_warn("failed to register filesystem!\n");
410 goto out;
411 }
412 return 0;
413 out:
414 for (i = 0; i < MAX_CODADEVS; i++)
415 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
416 class_destroy(coda_psdev_class);
417 unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
418 coda_sysctl_clean();
419 out1:
420 coda_destroy_inodecache();
421 out2:
422 return status;
423 }
424
exit_coda(void)425 static void __exit exit_coda(void)
426 {
427 int err, i;
428
429 err = unregister_filesystem(&coda_fs_type);
430 if (err != 0)
431 pr_warn("failed to unregister filesystem\n");
432 for (i = 0; i < MAX_CODADEVS; i++)
433 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
434 class_destroy(coda_psdev_class);
435 unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
436 coda_sysctl_clean();
437 coda_destroy_inodecache();
438 }
439
440 module_init(init_coda);
441 module_exit(exit_coda);
442
443