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
 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(THIS_MODULE, "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