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   1 /*
   2  * net/sunrpc/rpc_pipe.c
   3  *
   4  * Userland/kernel interface for rpcauth_gss.
   5  * Code shamelessly plagiarized from fs/nfsd/nfsctl.c
   6  * and fs/sysfs/inode.c
   7  *
   8  * Copyright (c) 2002, Trond Myklebust <trond.myklebust@fys.uio.no>
   9  *
  10  */
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/string.h>
  14 #include <linux/pagemap.h>
  15 #include <linux/mount.h>
  16 #include <linux/namei.h>
  17 #include <linux/fsnotify.h>
  18 #include <linux/kernel.h>
  19
  20 #include <asm/ioctls.h>
  21 #include <linux/fs.h>
  22 #include <linux/poll.h>
  23 #include <linux/wait.h>
  24 #include <linux/seq_file.h>
  25
  26 #include <linux/sunrpc/clnt.h>
  27 #include <linux/workqueue.h>
  28 #include <linux/sunrpc/rpc_pipe_fs.h>
  29
  30 static struct vfsmount *rpc_mount __read_mostly;
  31 static int rpc_mount_count;
  32
  33 static struct file_system_type rpc_pipe_fs_type;
  34
  35
  36 static struct kmem_cache *rpc_inode_cachep __read_mostly;
  37
  38 #define RPC_UPCALL_TIMEOUT (30*HZ)
  39
  40 static void rpc_purge_list(struct rpc_inode *rpci, struct list_head *head,
  41                 void (*destroy_msg)(struct rpc_pipe_msg *), int err)
  42 {
  43         struct rpc_pipe_msg *msg;
  44
  45         if (list_empty(head))
  46                 return;
  47         do {
  48                 msg = list_entry(head->next, struct rpc_pipe_msg, list);
  49                 list_del(&msg->list);
  50                 msg->errno = err;
  51                 destroy_msg(msg);
  52         } while (!list_empty(head));
  53         wake_up(&rpci->waitq);
  54 }
  55
  56 static void
  57 rpc_timeout_upcall_queue(struct work_struct *work)
  58 {
  59         LIST_HEAD(free_list);
  60         struct rpc_inode *rpci =
  61                 container_of(work, struct rpc_inode, queue_timeout.work);
  62         struct inode *inode = &rpci->vfs_inode;
  63         void (*destroy_msg)(struct rpc_pipe_msg *);
  64
  65         spin_lock(&inode->i_lock);
  66         if (rpci->ops == NULL) {
  67                 spin_unlock(&inode->i_lock);
  68                 return;
  69         }
  70         destroy_msg = rpci->ops->destroy_msg;
  71         if (rpci->nreaders == 0) {
  72                 list_splice_init(&rpci->pipe, &free_list);
  73                 rpci->pipelen = 0;
  74         }
  75         spin_unlock(&inode->i_lock);
  76         rpc_purge_list(rpci, &free_list, destroy_msg, -ETIMEDOUT);
  77 }
  78
  79 /**
  80  * rpc_queue_upcall
  81  * @inode: inode of upcall pipe on which to queue given message
  82  * @msg: message to queue
  83  *
  84  * Call with an @inode created by rpc_mkpipe() to queue an upcall.
  85  * A userspace process may then later read the upcall by performing a
  86  * read on an open file for this inode.  It is up to the caller to
  87  * initialize the fields of @msg (other than @msg->list) appropriately.
  88  */
  89 int
  90 rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
  91 {
  92         struct rpc_inode *rpci = RPC_I(inode);
  93         int res = -EPIPE;
  94
  95         spin_lock(&inode->i_lock);
  96         if (rpci->ops == NULL)
  97                 goto out;
  98         if (rpci->nreaders) {
  99                 list_add_tail(&msg->list, &rpci->pipe);
 100                 rpci->pipelen += msg->len;
 101                 res = 0;
 102         } else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
 103                 if (list_empty(&rpci->pipe))
 104                         queue_delayed_work(rpciod_workqueue,
 105                                         &rpci->queue_timeout,
 106                                         RPC_UPCALL_TIMEOUT);
 107                 list_add_tail(&msg->list, &rpci->pipe);
 108                 rpci->pipelen += msg->len;
 109                 res = 0;
 110         }
 111 out:
 112         spin_unlock(&inode->i_lock);
 113         wake_up(&rpci->waitq);
 114         return res;
 115 }
 116
 117 static inline void
 118 rpc_inode_setowner(struct inode *inode, void *private)
 119 {
 120         RPC_I(inode)->private = private;
 121 }
 122
 123 static void
 124 rpc_close_pipes(struct inode *inode)
 125 {
 126         struct rpc_inode *rpci = RPC_I(inode);
 127         struct rpc_pipe_ops *ops;
 128
 129         mutex_lock(&inode->i_mutex);
 130         ops = rpci->ops;
 131         if (ops != NULL) {
 132                 LIST_HEAD(free_list);
 133
 134                 spin_lock(&inode->i_lock);
 135                 rpci->nreaders = 0;
 136                 list_splice_init(&rpci->in_upcall, &free_list);
 137                 list_splice_init(&rpci->pipe, &free_list);
 138                 rpci->pipelen = 0;
 139                 rpci->ops = NULL;
 140                 spin_unlock(&inode->i_lock);
 141                 rpc_purge_list(rpci, &free_list, ops->destroy_msg, -EPIPE);
 142                 rpci->nwriters = 0;
 143                 if (ops->release_pipe)
 144                         ops->release_pipe(inode);
 145                 cancel_delayed_work_sync(&rpci->queue_timeout);
 146         }
 147         rpc_inode_setowner(inode, NULL);
 148         mutex_unlock(&inode->i_mutex);
 149 }
 150
 151 static struct inode *
 152 rpc_alloc_inode(struct super_block *sb)
 153 {
 154         struct rpc_inode *rpci;
 155         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
 156         if (!rpci)
 157                 return NULL;
 158         return &rpci->vfs_inode;
 159 }
 160
 161 static void
 162 rpc_destroy_inode(struct inode *inode)
 163 {
 164         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
 165 }
 166
 167 static int
 168 rpc_pipe_open(struct inode *inode, struct file *filp)
 169 {
 170         struct rpc_inode *rpci = RPC_I(inode);
 171         int res = -ENXIO;
 172
 173         mutex_lock(&inode->i_mutex);
 174         if (rpci->ops != NULL) {
 175                 if (filp->f_mode & FMODE_READ)
 176                         rpci->nreaders ++;
 177                 if (filp->f_mode & FMODE_WRITE)
 178                         rpci->nwriters ++;
 179                 res = 0;
 180         }
 181         mutex_unlock(&inode->i_mutex);
 182         return res;
 183 }
 184
 185 static int
 186 rpc_pipe_release(struct inode *inode, struct file *filp)
 187 {
 188         struct rpc_inode *rpci = RPC_I(inode);
 189         struct rpc_pipe_msg *msg;
 190
 191         mutex_lock(&inode->i_mutex);
 192         if (rpci->ops == NULL)
 193                 goto out;
 194         msg = (struct rpc_pipe_msg *)filp->private_data;
 195         if (msg != NULL) {
 196                 spin_lock(&inode->i_lock);
 197                 msg->errno = -EAGAIN;
 198                 list_del(&msg->list);
 199                 spin_unlock(&inode->i_lock);
 200                 rpci->ops->destroy_msg(msg);
 201         }
 202         if (filp->f_mode & FMODE_WRITE)
 203                 rpci->nwriters --;
 204         if (filp->f_mode & FMODE_READ) {
 205                 rpci->nreaders --;
 206                 if (rpci->nreaders == 0) {
 207                         LIST_HEAD(free_list);
 208                         spin_lock(&inode->i_lock);
 209                         list_splice_init(&rpci->pipe, &free_list);
 210                         rpci->pipelen = 0;
 211                         spin_unlock(&inode->i_lock);
 212                         rpc_purge_list(rpci, &free_list,
 213                                         rpci->ops->destroy_msg, -EAGAIN);
 214                 }
 215         }
 216         if (rpci->ops->release_pipe)
 217                 rpci->ops->release_pipe(inode);
 218 out:
 219         mutex_unlock(&inode->i_mutex);
 220         return 0;
 221 }
 222
 223 static ssize_t
 224 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
 225 {
 226         struct inode *inode = filp->f_path.dentry->d_inode;
 227         struct rpc_inode *rpci = RPC_I(inode);
 228         struct rpc_pipe_msg *msg;
 229         int res = 0;
 230
 231         mutex_lock(&inode->i_mutex);
 232         if (rpci->ops == NULL) {
 233                 res = -EPIPE;
 234                 goto out_unlock;
 235         }
 236         msg = filp->private_data;
 237         if (msg == NULL) {
 238                 spin_lock(&inode->i_lock);
 239                 if (!list_empty(&rpci->pipe)) {
 240                         msg = list_entry(rpci->pipe.next,
 241                                         struct rpc_pipe_msg,
 242                                         list);
 243                         list_move(&msg->list, &rpci->in_upcall);
 244                         rpci->pipelen -= msg->len;
 245                         filp->private_data = msg;
 246                         msg->copied = 0;
 247                 }
 248                 spin_unlock(&inode->i_lock);
 249                 if (msg == NULL)
 250                         goto out_unlock;
 251         }
 252         /* NOTE: it is up to the callback to update msg->copied */
 253         res = rpci->ops->upcall(filp, msg, buf, len);
 254         if (res < 0 || msg->len == msg->copied) {
 255                 filp->private_data = NULL;
 256                 spin_lock(&inode->i_lock);
 257                 list_del(&msg->list);
 258                 spin_unlock(&inode->i_lock);
 259                 rpci->ops->destroy_msg(msg);
 260         }
 261 out_unlock:
 262         mutex_unlock(&inode->i_mutex);
 263         return res;
 264 }
 265
 266 static ssize_t
 267 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
 268 {
 269         struct inode *inode = filp->f_path.dentry->d_inode;
 270         struct rpc_inode *rpci = RPC_I(inode);
 271         int res;
 272
 273         mutex_lock(&inode->i_mutex);
 274         res = -EPIPE;
 275         if (rpci->ops != NULL)
 276                 res = rpci->ops->downcall(filp, buf, len);
 277         mutex_unlock(&inode->i_mutex);
 278         return res;
 279 }
 280
 281 static unsigned int
 282 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
 283 {
 284         struct rpc_inode *rpci;
 285         unsigned int mask = 0;
 286
 287         rpci = RPC_I(filp->f_path.dentry->d_inode);
 288         poll_wait(filp, &rpci->waitq, wait);
 289
 290         mask = POLLOUT | POLLWRNORM;
 291         if (rpci->ops == NULL)
 292                 mask |= POLLERR | POLLHUP;
 293         if (filp->private_data || !list_empty(&rpci->pipe))
 294                 mask |= POLLIN | POLLRDNORM;
 295         return mask;
 296 }
 297
 298 static int
 299 rpc_pipe_ioctl(struct inode *ino, struct file *filp,
 300                 unsigned int cmd, unsigned long arg)
 301 {
 302         struct rpc_inode *rpci = RPC_I(filp->f_path.dentry->d_inode);
 303         int len;
 304
 305         switch (cmd) {
 306         case FIONREAD:
 307                 if (rpci->ops == NULL)
 308                         return -EPIPE;
 309                 len = rpci->pipelen;
 310                 if (filp->private_data) {
 311                         struct rpc_pipe_msg *msg;
 312                         msg = (struct rpc_pipe_msg *)filp->private_data;
 313                         len += msg->len - msg->copied;
 314                 }
 315                 return put_user(len, (int __user *)arg);
 316         default:
 317                 return -EINVAL;
 318         }
 319 }
 320
 321 static const struct file_operations rpc_pipe_fops = {
 322         .owner          = THIS_MODULE,
 323         .llseek         = no_llseek,
 324         .read           = rpc_pipe_read,
 325         .write          = rpc_pipe_write,
 326         .poll           = rpc_pipe_poll,
 327         .ioctl          = rpc_pipe_ioctl,
 328         .open           = rpc_pipe_open,
 329         .release        = rpc_pipe_release,
 330 };
 331
 332 static int
 333 rpc_show_info(struct seq_file *m, void *v)
 334 {
 335         struct rpc_clnt *clnt = m->private;
 336
 337         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
 338         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
 339                         clnt->cl_prog, clnt->cl_vers);
 340         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
 341         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
 342         seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
 343         return 0;
 344 }
 345
 346 static int
 347 rpc_info_open(struct inode *inode, struct file *file)
 348 {
 349         struct rpc_clnt *clnt;
 350         int ret = single_open(file, rpc_show_info, NULL);
 351
 352         if (!ret) {
 353                 struct seq_file *m = file->private_data;
 354                 mutex_lock(&inode->i_mutex);
 355                 clnt = RPC_I(inode)->private;
 356                 if (clnt) {
 357                         kref_get(&clnt->cl_kref);
 358                         m->private = clnt;
 359                 } else {
 360                         single_release(inode, file);
 361                         ret = -EINVAL;
 362                 }
 363                 mutex_unlock(&inode->i_mutex);
 364         }
 365         return ret;
 366 }
 367
 368 static int
 369 rpc_info_release(struct inode *inode, struct file *file)
 370 {
 371         struct seq_file *m = file->private_data;
 372         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
 373
 374         if (clnt)
 375                 rpc_release_client(clnt);
 376         return single_release(inode, file);
 377 }
 378
 379 static const struct file_operations rpc_info_operations = {
 380         .owner          = THIS_MODULE,
 381         .open           = rpc_info_open,
 382         .read           = seq_read,
 383         .llseek         = seq_lseek,
 384         .release        = rpc_info_release,
 385 };
 386
 387
 388 /*
 389  * We have a single directory with 1 node in it.
 390  */
 391 enum {
 392         RPCAUTH_Root = 1,
 393         RPCAUTH_lockd,
 394         RPCAUTH_mount,
 395         RPCAUTH_nfs,
 396         RPCAUTH_portmap,
 397         RPCAUTH_statd,
 398         RPCAUTH_RootEOF
 399 };
 400
 401 /*
 402  * Description of fs contents.
 403  */
 404 struct rpc_filelist {
 405         char *name;
 406         const struct file_operations *i_fop;
 407         int mode;
 408 };
 409
 410 static struct rpc_filelist files[] = {
 411         [RPCAUTH_lockd] = {
 412                 .name = "lockd",
 413                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 414         },
 415         [RPCAUTH_mount] = {
 416                 .name = "mount",
 417                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 418         },
 419         [RPCAUTH_nfs] = {
 420                 .name = "nfs",
 421                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 422         },
 423         [RPCAUTH_portmap] = {
 424                 .name = "portmap",
 425                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 426         },
 427         [RPCAUTH_statd] = {
 428                 .name = "statd",
 429                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 430         },
 431 };
 432
 433 enum {
 434         RPCAUTH_info = 2,
 435         RPCAUTH_EOF
 436 };
 437
 438 static struct rpc_filelist authfiles[] = {
 439         [RPCAUTH_info] = {
 440                 .name = "info",
 441                 .i_fop = &rpc_info_operations,
 442                 .mode = S_IFREG | S_IRUSR,
 443         },
 444 };
 445
 446 struct vfsmount *rpc_get_mount(void)
 447 {
 448         int err;
 449
 450         err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mount, &rpc_mount_count);
 451         if (err != 0)
 452                 return ERR_PTR(err);
 453         return rpc_mount;
 454 }
 455
 456 void rpc_put_mount(void)
 457 {
 458         simple_release_fs(&rpc_mount, &rpc_mount_count);
 459 }
 460
 461 static int rpc_delete_dentry(struct dentry *dentry)
 462 {
 463         return 1;
 464 }
 465
 466 static struct dentry_operations rpc_dentry_operations = {
 467         .d_delete = rpc_delete_dentry,
 468 };
 469
 470 static int
 471 rpc_lookup_parent(char *path, struct nameidata *nd)
 472 {
 473         struct vfsmount *mnt;
 474
 475         if (path[0] == '\0')
 476                 return -ENOENT;
 477
 478         mnt = rpc_get_mount();
 479         if (IS_ERR(mnt)) {
 480                 printk(KERN_WARNING "%s: %s failed to mount "
 481                                "pseudofilesystem \n", __FILE__, __FUNCTION__);
 482                 return PTR_ERR(mnt);
 483         }
 484
 485         if (vfs_path_lookup(mnt->mnt_root, mnt, path, LOOKUP_PARENT, nd)) {
 486                 printk(KERN_WARNING "%s: %s failed to find path %s\n",
 487                                 __FILE__, __FUNCTION__, path);
 488                 rpc_put_mount();
 489                 return -ENOENT;
 490         }
 491         return 0;
 492 }
 493
 494 static void
 495 rpc_release_path(struct nameidata *nd)
 496 {
 497         path_release(nd);
 498         rpc_put_mount();
 499 }
 500
 501 static struct inode *
 502 rpc_get_inode(struct super_block *sb, int mode)
 503 {
 504         struct inode *inode = new_inode(sb);
 505         if (!inode)
 506                 return NULL;
 507         inode->i_mode = mode;
 508         inode->i_uid = inode->i_gid = 0;
 509         inode->i_blocks = 0;
 510         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 511         switch(mode & S_IFMT) {
 512                 case S_IFDIR:
 513                         inode->i_fop = &simple_dir_operations;
 514                         inode->i_op = &simple_dir_inode_operations;
 515                         inc_nlink(inode);
 516                 default:
 517                         break;
 518         }
 519         return inode;
 520 }
 521
 522 /*
 523  * FIXME: This probably has races.
 524  */
 525 static void
 526 rpc_depopulate(struct dentry *parent, int start, int eof)
 527 {
 528         struct inode *dir = parent->d_inode;
 529         struct list_head *pos, *next;
 530         struct dentry *dentry, *dvec[10];
 531         int n = 0;
 532
 533         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
 534 repeat:
 535         spin_lock(&dcache_lock);
 536         list_for_each_safe(pos, next, &parent->d_subdirs) {
 537                 dentry = list_entry(pos, struct dentry, d_u.d_child);
 538                 if (!dentry->d_inode ||
 539                                 dentry->d_inode->i_ino < start ||
 540                                 dentry->d_inode->i_ino >= eof)
 541                         continue;
 542                 spin_lock(&dentry->d_lock);
 543                 if (!d_unhashed(dentry)) {
 544                         dget_locked(dentry);
 545                         __d_drop(dentry);
 546                         spin_unlock(&dentry->d_lock);
 547                         dvec[n++] = dentry;
 548                         if (n == ARRAY_SIZE(dvec))
 549                                 break;
 550                 } else
 551                         spin_unlock(&dentry->d_lock);
 552         }
 553         spin_unlock(&dcache_lock);
 554         if (n) {
 555                 do {
 556                         dentry = dvec[--n];
 557                         if (S_ISREG(dentry->d_inode->i_mode))
 558                                 simple_unlink(dir, dentry);
 559                         else if (S_ISDIR(dentry->d_inode->i_mode))
 560                                 simple_rmdir(dir, dentry);
 561                         d_delete(dentry);
 562                         dput(dentry);
 563                 } while (n);
 564                 goto repeat;
 565         }
 566         mutex_unlock(&dir->i_mutex);
 567 }
 568
 569 static int
 570 rpc_populate(struct dentry *parent,
 571                 struct rpc_filelist *files,
 572                 int start, int eof)
 573 {
 574         struct inode *inode, *dir = parent->d_inode;
 575         void *private = RPC_I(dir)->private;
 576         struct dentry *dentry;
 577         int mode, i;
 578
 579         mutex_lock(&dir->i_mutex);
 580         for (i = start; i < eof; i++) {
 581                 dentry = d_alloc_name(parent, files[i].name);
 582                 if (!dentry)
 583                         goto out_bad;
 584                 dentry->d_op = &rpc_dentry_operations;
 585                 mode = files[i].mode;
 586                 inode = rpc_get_inode(dir->i_sb, mode);
 587                 if (!inode) {
 588                         dput(dentry);
 589                         goto out_bad;
 590                 }
 591                 inode->i_ino = i;
 592                 if (files[i].i_fop)
 593                         inode->i_fop = files[i].i_fop;
 594                 if (private)
 595                         rpc_inode_setowner(inode, private);
 596                 if (S_ISDIR(mode))
 597                         inc_nlink(dir);
 598                 d_add(dentry, inode);
 599                 fsnotify_create(dir, dentry);
 600         }
 601         mutex_unlock(&dir->i_mutex);
 602         return 0;
 603 out_bad:
 604         mutex_unlock(&dir->i_mutex);
 605         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 606                         __FILE__, __FUNCTION__, parent->d_name.name);
 607         return -ENOMEM;
 608 }
 609
 610 static int
 611 __rpc_mkdir(struct inode *dir, struct dentry *dentry)
 612 {
 613         struct inode *inode;
 614
 615         inode = rpc_get_inode(dir->i_sb, S_IFDIR | S_IRUGO | S_IXUGO);
 616         if (!inode)
 617                 goto out_err;
 618         inode->i_ino = iunique(dir->i_sb, 100);
 619         d_instantiate(dentry, inode);
 620         inc_nlink(dir);
 621         fsnotify_mkdir(dir, dentry);
 622         return 0;
 623 out_err:
 624         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
 625                         __FILE__, __FUNCTION__, dentry->d_name.name);
 626         return -ENOMEM;
 627 }
 628
 629 static int
 630 __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 631 {
 632         int error;
 633         error = simple_rmdir(dir, dentry);
 634         if (!error)
 635                 d_delete(dentry);
 636         return error;
 637 }
 638
 639 static struct dentry *
 640 rpc_lookup_create(struct dentry *parent, const char *name, int len, int exclusive)
 641 {
 642         struct inode *dir = parent->d_inode;
 643         struct dentry *dentry;
 644
 645         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 646         dentry = lookup_one_len(name, parent, len);
 647         if (IS_ERR(dentry))
 648                 goto out_err;
 649         if (!dentry->d_inode)
 650                 dentry->d_op = &rpc_dentry_operations;
 651         else if (exclusive) {
 652                 dput(dentry);
 653                 dentry = ERR_PTR(-EEXIST);
 654                 goto out_err;
 655         }
 656         return dentry;
 657 out_err:
 658         mutex_unlock(&dir->i_mutex);
 659         return dentry;
 660 }
 661
 662 static struct dentry *
 663 rpc_lookup_negative(char *path, struct nameidata *nd)
 664 {
 665         struct dentry *dentry;
 666         int error;
 667
 668         if ((error = rpc_lookup_parent(path, nd)) != 0)
 669                 return ERR_PTR(error);
 670         dentry = rpc_lookup_create(nd->dentry, nd->last.name, nd->last.len, 1);
 671         if (IS_ERR(dentry))
 672                 rpc_release_path(nd);
 673         return dentry;
 674 }
 675
 676 /**
 677  * rpc_mkdir - Create a new directory in rpc_pipefs
 678  * @path: path from the rpc_pipefs root to the new directory
 679  * @rpc_clnt: rpc client to associate with this directory
 680  *
 681  * This creates a directory at the given @path associated with
 682  * @rpc_clnt, which will contain a file named "info" with some basic
 683  * information about the client, together with any "pipes" that may
 684  * later be created using rpc_mkpipe().
 685  */
 686 struct dentry *
 687 rpc_mkdir(char *path, struct rpc_clnt *rpc_client)
 688 {
 689         struct nameidata nd;
 690         struct dentry *dentry;
 691         struct inode *dir;
 692         int error;
 693
 694         dentry = rpc_lookup_negative(path, &nd);
 695         if (IS_ERR(dentry))
 696                 return dentry;
 697         dir = nd.dentry->d_inode;
 698         if ((error = __rpc_mkdir(dir, dentry)) != 0)
 699                 goto err_dput;
 700         RPC_I(dentry->d_inode)->private = rpc_client;
 701         error = rpc_populate(dentry, authfiles,
 702                         RPCAUTH_info, RPCAUTH_EOF);
 703         if (error)
 704                 goto err_depopulate;
 705         dget(dentry);
 706 out:
 707         mutex_unlock(&dir->i_mutex);
 708         rpc_release_path(&nd);
 709         return dentry;
 710 err_depopulate:
 711         rpc_depopulate(dentry, RPCAUTH_info, RPCAUTH_EOF);
 712         __rpc_rmdir(dir, dentry);
 713 err_dput:
 714         dput(dentry);
 715         printk(KERN_WARNING "%s: %s() failed to create directory %s (errno = %d)\n",
 716                         __FILE__, __FUNCTION__, path, error);
 717         dentry = ERR_PTR(error);
 718         goto out;
 719 }
 720
 721 /**
 722  * rpc_rmdir - Remove a directory created with rpc_mkdir()
 723  * @dentry: directory to remove
 724  */
 725 int
 726 rpc_rmdir(struct dentry *dentry)
 727 {
 728         struct dentry *parent;
 729         struct inode *dir;
 730         int error;
 731
 732         parent = dget_parent(dentry);
 733         dir = parent->d_inode;
 734         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 735         rpc_depopulate(dentry, RPCAUTH_info, RPCAUTH_EOF);
 736         error = __rpc_rmdir(dir, dentry);
 737         dput(dentry);
 738         mutex_unlock(&dir->i_mutex);
 739         dput(parent);
 740         return error;
 741 }
 742
 743 /**
 744  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
 745  * @parent: dentry of directory to create new "pipe" in
 746  * @name: name of pipe
 747  * @private: private data to associate with the pipe, for the caller's use
 748  * @ops: operations defining the behavior of the pipe: upcall, downcall,
 749  *      release_pipe, and destroy_msg.
 750  *
 751  * Data is made available for userspace to read by calls to
 752  * rpc_queue_upcall().  The actual reads will result in calls to
 753  * @ops->upcall, which will be called with the file pointer,
 754  * message, and userspace buffer to copy to.
 755  *
 756  * Writes can come at any time, and do not necessarily have to be
 757  * responses to upcalls.  They will result in calls to @msg->downcall.
 758  *
 759  * The @private argument passed here will be available to all these methods
 760  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
 761  */
 762 struct dentry *
 763 rpc_mkpipe(struct dentry *parent, const char *name, void *private, struct rpc_pipe_ops *ops, int flags)
 764 {
 765         struct dentry *dentry;
 766         struct inode *dir, *inode;
 767         struct rpc_inode *rpci;
 768
 769         dentry = rpc_lookup_create(parent, name, strlen(name), 0);
 770         if (IS_ERR(dentry))
 771                 return dentry;
 772         dir = parent->d_inode;
 773         if (dentry->d_inode) {
 774                 rpci = RPC_I(dentry->d_inode);
 775                 if (rpci->private != private ||
 776                                 rpci->ops != ops ||
 777                                 rpci->flags != flags) {
 778                         dput (dentry);
 779                         dentry = ERR_PTR(-EBUSY);
 780                 }
 781                 rpci->nkern_readwriters++;
 782                 goto out;
 783         }
 784         inode = rpc_get_inode(dir->i_sb, S_IFIFO | S_IRUSR | S_IWUSR);
 785         if (!inode)
 786                 goto err_dput;
 787         inode->i_ino = iunique(dir->i_sb, 100);
 788         inode->i_fop = &rpc_pipe_fops;
 789         d_instantiate(dentry, inode);
 790         rpci = RPC_I(inode);
 791         rpci->private = private;
 792         rpci->flags = flags;
 793         rpci->ops = ops;
 794         rpci->nkern_readwriters = 1;
 795         fsnotify_create(dir, dentry);
 796         dget(dentry);
 797 out:
 798         mutex_unlock(&dir->i_mutex);
 799         return dentry;
 800 err_dput:
 801         dput(dentry);
 802         dentry = ERR_PTR(-ENOMEM);
 803         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
 804                         __FILE__, __FUNCTION__, parent->d_name.name, name,
 805                         -ENOMEM);
 806         goto out;
 807 }
 808
 809 /**
 810  * rpc_unlink - remove a pipe
 811  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
 812  *
 813  * After this call, lookups will no longer find the pipe, and any
 814  * attempts to read or write using preexisting opens of the pipe will
 815  * return -EPIPE.
 816  */
 817 int
 818 rpc_unlink(struct dentry *dentry)
 819 {
 820         struct dentry *parent;
 821         struct inode *dir;
 822         int error = 0;
 823
 824         parent = dget_parent(dentry);
 825         dir = parent->d_inode;
 826         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 827         if (--RPC_I(dentry->d_inode)->nkern_readwriters == 0) {
 828                 rpc_close_pipes(dentry->d_inode);
 829                 error = simple_unlink(dir, dentry);
 830                 if (!error)
 831                         d_delete(dentry);
 832         }
 833         dput(dentry);
 834         mutex_unlock(&dir->i_mutex);
 835         dput(parent);
 836         return error;
 837 }
 838
 839 /*
 840  * populate the filesystem
 841  */
 842 static struct super_operations s_ops = {
 843         .alloc_inode    = rpc_alloc_inode,
 844         .destroy_inode  = rpc_destroy_inode,
 845         .statfs         = simple_statfs,
 846 };
 847
 848 #define RPCAUTH_GSSMAGIC 0x67596969
 849
 850 static int
 851 rpc_fill_super(struct super_block *sb, void *data, int silent)
 852 {
 853         struct inode *inode;
 854         struct dentry *root;
 855
 856         sb->s_blocksize = PAGE_CACHE_SIZE;
 857         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 858         sb->s_magic = RPCAUTH_GSSMAGIC;
 859         sb->s_op = &s_ops;
 860         sb->s_time_gran = 1;
 861
 862         inode = rpc_get_inode(sb, S_IFDIR | 0755);
 863         if (!inode)
 864                 return -ENOMEM;
 865         root = d_alloc_root(inode);
 866         if (!root) {
 867                 iput(inode);
 868                 return -ENOMEM;
 869         }
 870         if (rpc_populate(root, files, RPCAUTH_Root + 1, RPCAUTH_RootEOF))
 871                 goto out;
 872         sb->s_root = root;
 873         return 0;
 874 out:
 875         d_genocide(root);
 876         dput(root);
 877         return -ENOMEM;
 878 }
 879
 880 static int
 881 rpc_get_sb(struct file_system_type *fs_type,
 882                 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 883 {
 884         return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
 885 }
 886
 887 static struct file_system_type rpc_pipe_fs_type = {
 888         .owner          = THIS_MODULE,
 889         .name           = "rpc_pipefs",
 890         .get_sb         = rpc_get_sb,
 891         .kill_sb        = kill_litter_super,
 892 };
 893
 894 static void
 895 init_once(struct kmem_cache * cachep, void *foo)
 896 {
 897         struct rpc_inode *rpci = (struct rpc_inode *) foo;
 898
 899         inode_init_once(&rpci->vfs_inode);
 900         rpci->private = NULL;
 901         rpci->nreaders = 0;
 902         rpci->nwriters = 0;
 903         INIT_LIST_HEAD(&rpci->in_upcall);
 904         INIT_LIST_HEAD(&rpci->in_downcall);
 905         INIT_LIST_HEAD(&rpci->pipe);
 906         rpci->pipelen = 0;
 907         init_waitqueue_head(&rpci->waitq);
 908         INIT_DELAYED_WORK(&rpci->queue_timeout,
 909                             rpc_timeout_upcall_queue);
 910         rpci->ops = NULL;
 911 }
 912
 913 int register_rpc_pipefs(void)
 914 {
 915         int err;
 916
 917         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
 918                                 sizeof(struct rpc_inode),
 919                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
 920                                                 SLAB_MEM_SPREAD),
 921                                 init_once);
 922         if (!rpc_inode_cachep)
 923                 return -ENOMEM;
 924         err = register_filesystem(&rpc_pipe_fs_type);
 925         if (err) {
 926                 kmem_cache_destroy(rpc_inode_cachep);
 927                 return err;
 928         }
 929
 930         return 0;
 931 }
 932
 933 void unregister_rpc_pipefs(void)
 934 {
 935         kmem_cache_destroy(rpc_inode_cachep);
 936         unregister_filesystem(&rpc_pipe_fs_type);
 937 }