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(filp: file, wait_address: &vcp->vc_waitq, p: wait); |
64 | mutex_lock(&vcp->vc_mutex); |
65 | if (!list_empty(head: &vcp->vc_pending)) |
66 | mask |= EPOLLIN | EPOLLRDNORM; |
67 | mutex_unlock(lock: &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(to: &hdr, from: buf, n: 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(ptr: dcbuf)) { |
128 | retval = PTR_ERR(ptr: dcbuf); |
129 | goto out; |
130 | } |
131 | |
132 | /* what downcall errors does Venus handle ? */ |
133 | error = coda_downcall(vcp, opcode: hdr.opcode, out: dcbuf, nbytes); |
134 | |
135 | kvfree(addr: 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(entry: &req->uc_chain); |
153 | break; |
154 | } |
155 | } |
156 | mutex_unlock(lock: &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(to: req->uc_data, from: buf, n: 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(fd: 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(wq_head: &vcp->vc_waitq, wq_entry: &wait); |
218 | set_current_state(TASK_INTERRUPTIBLE); |
219 | |
220 | while (list_empty(head: &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(lock: &vcp->vc_mutex); |
230 | schedule(); |
231 | mutex_lock(&vcp->vc_mutex); |
232 | } |
233 | |
234 | set_current_state(TASK_RUNNING); |
235 | remove_wait_queue(wq_head: &vcp->vc_waitq, wq_entry: &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(entry: &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(to: buf, from: req->uc_data, n: 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(new: &(req->uc_chain), head: &vcp->vc_processing); |
258 | goto out; |
259 | } |
260 | |
261 | kvfree(addr: req->uc_data); |
262 | kfree(objp: req); |
263 | out: |
264 | mutex_unlock(lock: &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(list: &vcp->vc_pending); |
291 | INIT_LIST_HEAD(list: &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(lock: &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(entry: &req->uc_chain); |
320 | |
321 | /* Async requests need to be freed here */ |
322 | if (req->uc_flags & CODA_REQ_ASYNC) { |
323 | kvfree(addr: req->uc_data); |
324 | kfree(objp: 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(entry: &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(lock: &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, name: "coda" , fops: &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(name: "coda" ); |
365 | if (IS_ERR(ptr: coda_psdev_class)) { |
366 | err = PTR_ERR(ptr: 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(cls: coda_psdev_class, NULL, |
372 | MKDEV(CODA_PSDEV_MAJOR, i), NULL, fmt: "cfs%d" , i); |
373 | } |
374 | coda_sysctl_init(); |
375 | goto out; |
376 | |
377 | out_chrdev: |
378 | unregister_chrdev(CODA_PSDEV_MAJOR, name: "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(cls: coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i)); |
412 | class_destroy(cls: coda_psdev_class); |
413 | unregister_chrdev(CODA_PSDEV_MAJOR, name: "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(cls: coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i)); |
430 | class_destroy(cls: coda_psdev_class); |
431 | unregister_chrdev(CODA_PSDEV_MAJOR, name: "coda" ); |
432 | coda_sysctl_clean(); |
433 | coda_destroy_inodecache(); |
434 | } |
435 | |
436 | module_init(init_coda); |
437 | module_exit(exit_coda); |
438 | |
439 | |