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
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
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
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
126 dcbuf = vmemdup_user(buf, nbytes);
127 if (IS_ERR(dcbuf)) {
128 retval = PTR_ERR(dcbuf);
129 goto out;
130 }
131
132 /* what downcall errors does Venus handle ? */
133 error = coda_downcall(vcp, hdr.opcode, dcbuf, nbytes);
134
135 kvfree(dcbuf);
136 if (error) {
137 pr_warn("%s: coda_downcall error: %d\n",
138 __func__, error);
139 retval = error;
140 goto out;
141 }
142 count = nbytes;
143 goto out;
144 }
145
146 /* Look for the message on the processing queue. */
147 mutex_lock(&vcp->vc_mutex);
148 list_for_each(lh, &vcp->vc_processing) {
149 tmp = list_entry(lh, struct upc_req , uc_chain);
150 if (tmp->uc_unique == hdr.unique) {
151 req = tmp;
152 list_del(&req->uc_chain);
153 break;
154 }
155 }
156 mutex_unlock(&vcp->vc_mutex);
157
158 if (!req) {
159 pr_warn("%s: msg (%d, %d) not found\n",
160 __func__, hdr.opcode, hdr.unique);
161 retval = -ESRCH;
162 goto out;
163 }
164
165 /* move data into response buffer. */
166 if (req->uc_outSize < nbytes) {
167 pr_warn("%s: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d.\n",
168 __func__, req->uc_outSize, (long)nbytes,
169 hdr.opcode, hdr.unique);
170 nbytes = req->uc_outSize; /* don't have more space! */
171 }
172 if (copy_from_user(req->uc_data, buf, nbytes)) {
173 req->uc_flags |= CODA_REQ_ABORT;
174 wake_up(&req->uc_sleep);
175 retval = -EFAULT;
176 goto out;
177 }
178
179 /* adjust outsize. is this useful ?? */
180 req->uc_outSize = nbytes;
181 req->uc_flags |= CODA_REQ_WRITE;
182 count = nbytes;
183
184 /* Convert filedescriptor into a file handle */
185 if (req->uc_opcode == CODA_OPEN_BY_FD) {
186 struct coda_open_by_fd_out *outp =
187 (struct coda_open_by_fd_out *)req->uc_data;
188 if (!outp->oh.result) {
189 outp->fh = fget(outp->fd);
190 if (!outp->fh)
191 return -EBADF;
192 }
193 }
194
195 wake_up(&req->uc_sleep);
196 out:
197 return(count ? count : retval);
198 }
199
200 /*
201 * Read a message from the kernel to Venus
202 */
203
204 static ssize_t coda_psdev_read(struct file * file, char __user * buf,
205 size_t nbytes, loff_t *off)
206 {
207 DECLARE_WAITQUEUE(wait, current);
208 struct venus_comm *vcp = (struct venus_comm *) file->private_data;
209 struct upc_req *req;
210 ssize_t retval = 0, count = 0;
211
212 if (nbytes == 0)
213 return 0;
214
215 mutex_lock(&vcp->vc_mutex);
216
217 add_wait_queue(&vcp->vc_waitq, &wait);
218 set_current_state(TASK_INTERRUPTIBLE);
219
220 while (list_empty(&vcp->vc_pending)) {
221 if (file->f_flags & O_NONBLOCK) {
222 retval = -EAGAIN;
223 break;
224 }
225 if (signal_pending(current)) {
226 retval = -ERESTARTSYS;
227 break;
228 }
229 mutex_unlock(&vcp->vc_mutex);
230 schedule();
231 mutex_lock(&vcp->vc_mutex);
232 }
233
234 set_current_state(TASK_RUNNING);
235 remove_wait_queue(&vcp->vc_waitq, &wait);
236
237 if (retval)
238 goto out;
239
240 req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain);
241 list_del(&req->uc_chain);
242
243 /* Move the input args into userspace */
244 count = req->uc_inSize;
245 if (nbytes < req->uc_inSize) {
246 pr_warn("%s: Venus read %ld bytes of %d in message\n",
247 __func__, (long)nbytes, req->uc_inSize);
248 count = nbytes;
249 }
250
251 if (copy_to_user(buf, req->uc_data, count))
252 retval = -EFAULT;
253
254 /* If request was not a signal, enqueue and don't free */
255 if (!(req->uc_flags & CODA_REQ_ASYNC)) {
256 req->uc_flags |= CODA_REQ_READ;
257 list_add_tail(&(req->uc_chain), &vcp->vc_processing);
258 goto out;
259 }
260
261 kvfree(req->uc_data);
262 kfree(req);
263 out:
264 mutex_unlock(&vcp->vc_mutex);
265 return (count ? count : retval);
266 }
267
268 static int coda_psdev_open(struct inode * inode, struct file * file)
269 {
270 struct venus_comm *vcp;
271 int idx, err;
272
273 if (task_active_pid_ns(current) != &init_pid_ns)
274 return -EINVAL;
275
276 if (current_user_ns() != &init_user_ns)
277 return -EINVAL;
278
279 idx = iminor(inode);
280 if (idx < 0 || idx >= MAX_CODADEVS)
281 return -ENODEV;
282
283 err = -EBUSY;
284 vcp = &coda_comms[idx];
285 mutex_lock(&vcp->vc_mutex);
286
287 if (!vcp->vc_inuse) {
288 vcp->vc_inuse++;
289
290 INIT_LIST_HEAD(&vcp->vc_pending);
291 INIT_LIST_HEAD(&vcp->vc_processing);
292 init_waitqueue_head(&vcp->vc_waitq);
293 vcp->vc_sb = NULL;
294 vcp->vc_seq = 0;
295
296 file->private_data = vcp;
297 err = 0;
298 }
299
300 mutex_unlock(&vcp->vc_mutex);
301 return err;
302 }
303
304
305 static int coda_psdev_release(struct inode * inode, struct file * file)
306 {
307 struct venus_comm *vcp = (struct venus_comm *) file->private_data;
308 struct upc_req *req, *tmp;
309
310 if (!vcp || !vcp->vc_inuse ) {
311 pr_warn("%s: Not open.\n", __func__);
312 return -1;
313 }
314
315 mutex_lock(&vcp->vc_mutex);
316
317 /* Wakeup clients so they can return. */
318 list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) {
319 list_del(&req->uc_chain);
320
321 /* Async requests need to be freed here */
322 if (req->uc_flags & CODA_REQ_ASYNC) {
323 kvfree(req->uc_data);
324 kfree(req);
325 continue;
326 }
327 req->uc_flags |= CODA_REQ_ABORT;
328 wake_up(&req->uc_sleep);
329 }
330
331 list_for_each_entry_safe(req, tmp, &vcp->vc_processing, uc_chain) {
332 list_del(&req->uc_chain);
333
334 req->uc_flags |= CODA_REQ_ABORT;
335 wake_up(&req->uc_sleep);
336 }
337
338 file->private_data = NULL;
339 vcp->vc_inuse--;
340 mutex_unlock(&vcp->vc_mutex);
341 return 0;
342 }
343
344
345 static const struct file_operations coda_psdev_fops = {
346 .owner = THIS_MODULE,
347 .read = coda_psdev_read,
348 .write = coda_psdev_write,
349 .poll = coda_psdev_poll,
350 .unlocked_ioctl = coda_psdev_ioctl,
351 .open = coda_psdev_open,
352 .release = coda_psdev_release,
353 .llseek = noop_llseek,
354 };
355
356 static int __init init_coda_psdev(void)
357 {
358 int i, err = 0;
359 if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) {
360 pr_err("%s: unable to get major %d\n",
361 __func__, CODA_PSDEV_MAJOR);
362 return -EIO;
363 }
364 coda_psdev_class = class_create("coda");
365 if (IS_ERR(coda_psdev_class)) {
366 err = PTR_ERR(coda_psdev_class);
367 goto out_chrdev;
368 }
369 for (i = 0; i < MAX_CODADEVS; i++) {
370 mutex_init(&(&coda_comms[i])->vc_mutex);
371 device_create(coda_psdev_class, NULL,
372 MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i);
373 }
374 coda_sysctl_init();
375 goto out;
376
377 out_chrdev:
378 unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
379 out:
380 return err;
381 }
382
383 MODULE_AUTHOR("Jan Harkes, Peter J. Braam");
384 MODULE_DESCRIPTION("Coda Distributed File System VFS interface");
385 MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR);
386 MODULE_LICENSE("GPL");
387 MODULE_VERSION("7.2");
388
389 static int __init init_coda(void)
390 {
391 int status;
392 int i;
393
394 status = coda_init_inodecache();
395 if (status)
396 goto out2;
397 status = init_coda_psdev();
398 if ( status ) {
399 pr_warn("Problem (%d) in init_coda_psdev\n", status);
400 goto out1;
401 }
402
403 status = register_filesystem(&coda_fs_type);
404 if (status) {
405 pr_warn("failed to register filesystem!\n");
406 goto out;
407 }
408 return 0;
409 out:
410 for (i = 0; i < MAX_CODADEVS; i++)
411 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
412 class_destroy(coda_psdev_class);
413 unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
414 coda_sysctl_clean();
415 out1:
416 coda_destroy_inodecache();
417 out2:
418 return status;
419 }
420
421 static void __exit exit_coda(void)
422 {
423 int err, i;
424
425 err = unregister_filesystem(&coda_fs_type);
426 if (err != 0)
427 pr_warn("failed to unregister filesystem\n");
428 for (i = 0; i < MAX_CODADEVS; i++)
429 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
430 class_destroy(coda_psdev_class);
431 unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
432 coda_sysctl_clean();
433 coda_destroy_inodecache();
434 }
435
436 module_init(init_coda);
437 module_exit(exit_coda);
438
439
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