fs/coda/psdev.c

   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 <linux/coda_psdev.h>
  42
  43 #include "coda_linux.h"
  44
  45 #include "coda_int.h"
  46
  47 /* statistics */
  48 int           coda_hard;         /* allows signals during upcalls */
  49 unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */
  50
  51
  52 struct venus_comm coda_comms[MAX_CODADEVS];
  53 static struct class *coda_psdev_class;
  54
  55 /*
  56  * Device operations
  57  */
  58
  59 static __poll_t coda_psdev_poll(struct file *file, poll_table * wait)
  60 {
  61         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
  62         __poll_t mask = EPOLLOUT | EPOLLWRNORM;
  63
  64         poll_wait(file, &vcp->vc_waitq, wait);
  65         mutex_lock(&vcp->vc_mutex);
  66         if (!list_empty(&vcp->vc_pending))
  67                 mask |= EPOLLIN | EPOLLRDNORM;
  68         mutex_unlock(&vcp->vc_mutex);
  69
  70         return mask;
  71 }
  72
  73 static long coda_psdev_ioctl(struct file * filp, unsigned int cmd, unsigned long arg)
  74 {
  75         unsigned int data;
  76
  77         switch(cmd) {
  78         case CIOC_KERNEL_VERSION:
  79                 data = CODA_KERNEL_VERSION;
  80                 return put_user(data, (int __user *) arg);
  81         default:
  82                 return -ENOTTY;
  83         }
  84
  85         return 0;
  86 }
  87
  88 /*
  89  *      Receive a message written by Venus to the psdev
  90  */
  91
  92 static ssize_t coda_psdev_write(struct file *file, const char __user *buf,
  93                                 size_t nbytes, loff_t *off)
  94 {
  95         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
  96         struct upc_req *req = NULL;
  97         struct upc_req *tmp;
  98         struct list_head *lh;
  99         struct coda_in_hdr hdr;
 100         ssize_t retval = 0, count = 0;
 101         int error;
 102
 103         /* Peek at the opcode, uniquefier */
 104         if (copy_from_user(&hdr, buf, 2 * sizeof(u_long)))
 105                 return -EFAULT;
 106
 107         if (DOWNCALL(hdr.opcode)) {
 108                 union outputArgs *dcbuf;
 109                 int size = sizeof(*dcbuf);
 110
 111                 if  ( nbytes < sizeof(struct coda_out_hdr) ) {
 112                         pr_warn("coda_downcall opc %d uniq %d, not enough!\n",
 113                                 hdr.opcode, hdr.unique);
 114                         count = nbytes;
 115                         goto out;
 116                 }
 117                 if ( nbytes > size ) {
 118                         pr_warn("downcall opc %d, uniq %d, too much!",
 119                                 hdr.opcode, hdr.unique);
 120                         nbytes = size;
 121                 }
 122                 CODA_ALLOC(dcbuf, union outputArgs *, nbytes);
 123                 if (copy_from_user(dcbuf, buf, nbytes)) {
 124                         CODA_FREE(dcbuf, nbytes);
 125                         retval = -EFAULT;
 126                         goto out;
 127                 }
 128
 129                 /* what downcall errors does Venus handle ? */
 130                 error = coda_downcall(vcp, hdr.opcode, dcbuf);
 131
 132                 CODA_FREE(dcbuf, nbytes);
 133                 if (error) {
 134                         pr_warn("%s: coda_downcall error: %d\n",
 135                                 __func__, error);
 136                         retval = error;
 137                         goto out;
 138                 }
 139                 count = nbytes;
 140                 goto out;
 141         }
 142
 143         /* Look for the message on the processing queue. */
 144         mutex_lock(&vcp->vc_mutex);
 145         list_for_each(lh, &vcp->vc_processing) {
 146                 tmp = list_entry(lh, struct upc_req , uc_chain);
 147                 if (tmp->uc_unique == hdr.unique) {
 148                         req = tmp;
 149                         list_del(&req->uc_chain);
 150                         break;
 151                 }
 152         }
 153         mutex_unlock(&vcp->vc_mutex);
 154
 155         if (!req) {
 156                 pr_warn("%s: msg (%d, %d) not found\n",
 157                         __func__, hdr.opcode, hdr.unique);
 158                 retval = -ESRCH;
 159                 goto out;
 160         }
 161
 162         /* move data into response buffer. */
 163         if (req->uc_outSize < nbytes) {
 164                 pr_warn("%s: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d.\n",
 165                         __func__, req->uc_outSize, (long)nbytes,
 166                         hdr.opcode, hdr.unique);
 167                 nbytes = req->uc_outSize; /* don't have more space! */
 168         }
 169         if (copy_from_user(req->uc_data, buf, nbytes)) {
 170                 req->uc_flags |= CODA_REQ_ABORT;
 171                 wake_up(&req->uc_sleep);
 172                 retval = -EFAULT;
 173                 goto out;
 174         }
 175
 176         /* adjust outsize. is this useful ?? */
 177         req->uc_outSize = nbytes;
 178         req->uc_flags |= CODA_REQ_WRITE;
 179         count = nbytes;
 180
 181         /* Convert filedescriptor into a file handle */
 182         if (req->uc_opcode == CODA_OPEN_BY_FD) {
 183                 struct coda_open_by_fd_out *outp =
 184                         (struct coda_open_by_fd_out *)req->uc_data;
 185                 if (!outp->oh.result)
 186                         outp->fh = fget(outp->fd);
 187         }
 188
 189         wake_up(&req->uc_sleep);
 190 out:
 191         return(count ? count : retval);
 192 }
 193
 194 /*
 195  *      Read a message from the kernel to Venus
 196  */
 197
 198 static ssize_t coda_psdev_read(struct file * file, char __user * buf,
 199                                size_t nbytes, loff_t *off)
 200 {
 201         DECLARE_WAITQUEUE(wait, current);
 202         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
 203         struct upc_req *req;
 204         ssize_t retval = 0, count = 0;
 205
 206         if (nbytes == 0)
 207                 return 0;
 208
 209         mutex_lock(&vcp->vc_mutex);
 210
 211         add_wait_queue(&vcp->vc_waitq, &wait);
 212         set_current_state(TASK_INTERRUPTIBLE);
 213
 214         while (list_empty(&vcp->vc_pending)) {
 215                 if (file->f_flags & O_NONBLOCK) {
 216                         retval = -EAGAIN;
 217                         break;
 218                 }
 219                 if (signal_pending(current)) {
 220                         retval = -ERESTARTSYS;
 221                         break;
 222                 }
 223                 mutex_unlock(&vcp->vc_mutex);
 224                 schedule();
 225                 mutex_lock(&vcp->vc_mutex);
 226         }
 227
 228         set_current_state(TASK_RUNNING);
 229         remove_wait_queue(&vcp->vc_waitq, &wait);
 230
 231         if (retval)
 232                 goto out;
 233
 234         req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain);
 235         list_del(&req->uc_chain);
 236
 237         /* Move the input args into userspace */
 238         count = req->uc_inSize;
 239         if (nbytes < req->uc_inSize) {
 240                 pr_warn("%s: Venus read %ld bytes of %d in message\n",
 241                         __func__, (long)nbytes, req->uc_inSize);
 242                 count = nbytes;
 243         }
 244
 245         if (copy_to_user(buf, req->uc_data, count))
 246                 retval = -EFAULT;
 247
 248         /* If request was not a signal, enqueue and don't free */
 249         if (!(req->uc_flags & CODA_REQ_ASYNC)) {
 250                 req->uc_flags |= CODA_REQ_READ;
 251                 list_add_tail(&(req->uc_chain), &vcp->vc_processing);
 252                 goto out;
 253         }
 254
 255         CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
 256         kfree(req);
 257 out:
 258         mutex_unlock(&vcp->vc_mutex);
 259         return (count ? count : retval);
 260 }
 261
 262 static int coda_psdev_open(struct inode * inode, struct file * file)
 263 {
 264         struct venus_comm *vcp;
 265         int idx, err;
 266
 267         if (task_active_pid_ns(current) != &init_pid_ns)
 268                 return -EINVAL;
 269
 270         if (current_user_ns() != &init_user_ns)
 271                 return -EINVAL;
 272
 273         idx = iminor(inode);
 274         if (idx < 0 || idx >= MAX_CODADEVS)
 275                 return -ENODEV;
 276
 277         err = -EBUSY;
 278         vcp = &coda_comms[idx];
 279         mutex_lock(&vcp->vc_mutex);
 280
 281         if (!vcp->vc_inuse) {
 282                 vcp->vc_inuse++;
 283
 284                 INIT_LIST_HEAD(&vcp->vc_pending);
 285                 INIT_LIST_HEAD(&vcp->vc_processing);
 286                 init_waitqueue_head(&vcp->vc_waitq);
 287                 vcp->vc_sb = NULL;
 288                 vcp->vc_seq = 0;
 289
 290                 file->private_data = vcp;
 291                 err = 0;
 292         }
 293
 294         mutex_unlock(&vcp->vc_mutex);
 295         return err;
 296 }
 297
 298
 299 static int coda_psdev_release(struct inode * inode, struct file * file)
 300 {
 301         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
 302         struct upc_req *req, *tmp;
 303
 304         if (!vcp || !vcp->vc_inuse ) {
 305                 pr_warn("%s: Not open.\n", __func__);
 306                 return -1;
 307         }
 308
 309         mutex_lock(&vcp->vc_mutex);
 310
 311         /* Wakeup clients so they can return. */
 312         list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) {
 313                 list_del(&req->uc_chain);
 314
 315                 /* Async requests need to be freed here */
 316                 if (req->uc_flags & CODA_REQ_ASYNC) {
 317                         CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
 318                         kfree(req);
 319                         continue;
 320                 }
 321                 req->uc_flags |= CODA_REQ_ABORT;
 322                 wake_up(&req->uc_sleep);
 323         }
 324
 325         list_for_each_entry_safe(req, tmp, &vcp->vc_processing, uc_chain) {
 326                 list_del(&req->uc_chain);
 327
 328                 req->uc_flags |= CODA_REQ_ABORT;
 329                 wake_up(&req->uc_sleep);
 330         }
 331
 332         file->private_data = NULL;
 333         vcp->vc_inuse--;
 334         mutex_unlock(&vcp->vc_mutex);
 335         return 0;
 336 }
 337
 338
 339 static const struct file_operations coda_psdev_fops = {
 340         .owner          = THIS_MODULE,
 341         .read           = coda_psdev_read,
 342         .write          = coda_psdev_write,
 343         .poll           = coda_psdev_poll,
 344         .unlocked_ioctl = coda_psdev_ioctl,
 345         .open           = coda_psdev_open,
 346         .release        = coda_psdev_release,
 347         .llseek         = noop_llseek,
 348 };
 349
 350 static int init_coda_psdev(void)
 351 {
 352         int i, err = 0;
 353         if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) {
 354                 pr_err("%s: unable to get major %d\n",
 355                        __func__, CODA_PSDEV_MAJOR);
 356               return -EIO;
 357         }
 358         coda_psdev_class = class_create(THIS_MODULE, "coda");
 359         if (IS_ERR(coda_psdev_class)) {
 360                 err = PTR_ERR(coda_psdev_class);
 361                 goto out_chrdev;
 362         }
 363         for (i = 0; i < MAX_CODADEVS; i++) {
 364                 mutex_init(&(&coda_comms[i])->vc_mutex);
 365                 device_create(coda_psdev_class, NULL,
 366                               MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i);
 367         }
 368         coda_sysctl_init();
 369         goto out;
 370
 371 out_chrdev:
 372         unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
 373 out:
 374         return err;
 375 }
 376
 377 MODULE_AUTHOR("Jan Harkes, Peter J. Braam");
 378 MODULE_DESCRIPTION("Coda Distributed File System VFS interface");
 379 MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR);
 380 MODULE_LICENSE("GPL");
 381 MODULE_VERSION("6.6");
 382
 383 static int __init init_coda(void)
 384 {
 385         int status;
 386         int i;
 387
 388         status = coda_init_inodecache();
 389         if (status)
 390                 goto out2;
 391         status = init_coda_psdev();
 392         if ( status ) {
 393                 pr_warn("Problem (%d) in init_coda_psdev\n", status);
 394                 goto out1;
 395         }
 396
 397         status = register_filesystem(&coda_fs_type);
 398         if (status) {
 399                 pr_warn("failed to register filesystem!\n");
 400                 goto out;
 401         }
 402         return 0;
 403 out:
 404         for (i = 0; i < MAX_CODADEVS; i++)
 405                 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
 406         class_destroy(coda_psdev_class);
 407         unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
 408         coda_sysctl_clean();
 409 out1:
 410         coda_destroy_inodecache();
 411 out2:
 412         return status;
 413 }
 414
 415 static void __exit exit_coda(void)
 416 {
 417         int err, i;
 418
 419         err = unregister_filesystem(&coda_fs_type);
 420         if (err != 0)
 421                 pr_warn("failed to unregister filesystem\n");
 422         for (i = 0; i < MAX_CODADEVS; i++)
 423                 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
 424         class_destroy(coda_psdev_class);
 425         unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
 426         coda_sysctl_clean();
 427         coda_destroy_inodecache();
 428 }
 429
 430 module_init(init_coda);
 431 module_exit(exit_coda);
 432