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 "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                 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
 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
 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
 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
 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
 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
 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