1 /* -*- linux-c -*- --------------------------------------------------------- * 2 * 3 * linux/fs/autofs/root.c 4 * 5 * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved 6 * 7 * This file is part of the Linux kernel and is made available under 8 * the terms of the GNU General Public License, version 2, or at your 9 * option, any later version, incorporated herein by reference. 10 * 11 * ------------------------------------------------------------------------- */ 12 13 #include <linux/errno.h> 14 #include <linux/stat.h> 15 #include <linux/param.h> 16 #include <linux/time.h> 17 #include <linux/smp_lock.h> 18 #include "autofs_i.h" 19 20 static int autofs_root_readdir(struct file *,void *,filldir_t); 21 static struct dentry *autofs_root_lookup(struct inode *,struct dentry *, struct nameidata *); 22 static int autofs_root_symlink(struct inode *,struct dentry *,const char *); 23 static int autofs_root_unlink(struct inode *,struct dentry *); 24 static int autofs_root_rmdir(struct inode *,struct dentry *); 25 static int autofs_root_mkdir(struct inode *,struct dentry *,int); 26 static int autofs_root_ioctl(struct inode *, struct file *,unsigned int,unsigned long); 27 28 struct file_operations autofs_root_operations = { 29 .read = generic_read_dir, 30 .readdir = autofs_root_readdir, 31 .ioctl = autofs_root_ioctl, 32 }; 33 34 struct inode_operations autofs_root_inode_operations = { 35 .lookup = autofs_root_lookup, 36 .unlink = autofs_root_unlink, 37 .symlink = autofs_root_symlink, 38 .mkdir = autofs_root_mkdir, 39 .rmdir = autofs_root_rmdir, 40 }; 41 42 static int autofs_root_readdir(struct file *filp, void *dirent, filldir_t filldir) 43 { 44 struct autofs_dir_ent *ent = NULL; 45 struct autofs_dirhash *dirhash; 46 struct autofs_sb_info *sbi; 47 struct inode * inode = filp->f_dentry->d_inode; 48 off_t onr, nr; 49 50 lock_kernel(); 51 52 sbi = autofs_sbi(inode->i_sb); 53 dirhash = &sbi->dirhash; 54 nr = filp->f_pos; 55 56 switch(nr) 57 { 58 case 0: 59 if (filldir(dirent, ".", 1, nr, inode->i_ino, DT_DIR) < 0) 60 goto out; 61 filp->f_pos = ++nr; 62 /* fall through */ 63 case 1: 64 if (filldir(dirent, "..", 2, nr, inode->i_ino, DT_DIR) < 0) 65 goto out; 66 filp->f_pos = ++nr; 67 /* fall through */ 68 default: 69 while ( onr = nr, ent = autofs_hash_enum(dirhash,&nr,ent) ) { 70 if ( !ent->dentry || d_mountpoint(ent->dentry) ) { 71 if (filldir(dirent,ent->name,ent->len,onr,ent->ino,DT_UNKNOWN) < 0) 72 goto out; 73 filp->f_pos = nr; 74 } 75 } 76 break; 77 } 78 79 out: 80 unlock_kernel(); 81 return 0; 82 } 83 84 static int try_to_fill_dentry(struct dentry *dentry, struct super_block *sb, struct autofs_sb_info *sbi) 85 { 86 struct inode * inode; 87 struct autofs_dir_ent *ent; 88 int status = 0; 89 90 if ( !(ent = autofs_hash_lookup(&sbi->dirhash, &dentry->d_name)) ) { 91 do { 92 if ( status && dentry->d_inode ) { 93 if ( status != -ENOENT ) 94 printk("autofs warning: lookup failure on positive dentry, status = %d, name = %s\n", status, dentry->d_name.name); 95 return 0; /* Try to get the kernel to invalidate this dentry */ 96 } 97 98 /* Turn this into a real negative dentry? */ 99 if (status == -ENOENT) { 100 dentry->d_time = jiffies + AUTOFS_NEGATIVE_TIMEOUT; 101 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING; 102 return 1; 103 } else if (status) { 104 /* Return a negative dentry, but leave it "pending" */ 105 return 1; 106 } 107 status = autofs_wait(sbi, &dentry->d_name); 108 } while (!(ent = autofs_hash_lookup(&sbi->dirhash, &dentry->d_name)) ); 109 } 110 111 /* Abuse this field as a pointer to the directory entry, used to 112 find the expire list pointers */ 113 dentry->d_time = (unsigned long) ent; 114 115 if (!dentry->d_inode) { 116 inode = iget(sb, ent->ino); 117 if (!inode) { 118 /* Failed, but leave pending for next time */ 119 return 1; 120 } 121 dentry->d_inode = inode; 122 } 123 124 /* If this is a directory that isn't a mount point, bitch at the 125 daemon and fix it in user space */ 126 if ( S_ISDIR(dentry->d_inode->i_mode) && !d_mountpoint(dentry) ) { 127 return !autofs_wait(sbi, &dentry->d_name); 128 } 129 130 /* We don't update the usages for the autofs daemon itself, this 131 is necessary for recursive autofs mounts */ 132 if ( !autofs_oz_mode(sbi) ) { 133 autofs_update_usage(&sbi->dirhash,ent); 134 } 135 136 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING; 137 return 1; 138 } 139 140 141 /* 142 * Revalidate is called on every cache lookup. Some of those 143 * cache lookups may actually happen while the dentry is not 144 * yet completely filled in, and revalidate has to delay such 145 * lookups.. 146 */ 147 static int autofs_revalidate(struct dentry * dentry, struct nameidata *nd) 148 { 149 struct inode * dir; 150 struct autofs_sb_info *sbi; 151 struct autofs_dir_ent *ent; 152 int res; 153 154 lock_kernel(); 155 dir = dentry->d_parent->d_inode; 156 sbi = autofs_sbi(dir->i_sb); 157 158 /* Pending dentry */ 159 if ( dentry->d_flags & DCACHE_AUTOFS_PENDING ) { 160 if (autofs_oz_mode(sbi)) 161 res = 1; 162 else 163 res = try_to_fill_dentry(dentry, dir->i_sb, sbi); 164 unlock_kernel(); 165 return res; 166 } 167 168 /* Negative dentry.. invalidate if "old" */ 169 if (!dentry->d_inode) { 170 unlock_kernel(); 171 return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT); 172 } 173 174 /* Check for a non-mountpoint directory */ 175 if ( S_ISDIR(dentry->d_inode->i_mode) && !d_mountpoint(dentry) ) { 176 if (autofs_oz_mode(sbi)) 177 res = 1; 178 else 179 res = try_to_fill_dentry(dentry, dir->i_sb, sbi); 180 unlock_kernel(); 181 return res; 182 } 183 184 /* Update the usage list */ 185 if ( !autofs_oz_mode(sbi) ) { 186 ent = (struct autofs_dir_ent *) dentry->d_time; 187 if ( ent ) 188 autofs_update_usage(&sbi->dirhash,ent); 189 } 190 unlock_kernel(); 191 return 1; 192 } 193 194 static struct dentry_operations autofs_dentry_operations = { 195 .d_revalidate = autofs_revalidate, 196 }; 197 198 static struct dentry *autofs_root_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) 199 { 200 struct autofs_sb_info *sbi; 201 int oz_mode; 202 203 DPRINTK(("autofs_root_lookup: name = ")); 204 lock_kernel(); 205 autofs_say(dentry->d_name.name,dentry->d_name.len); 206 207 if (dentry->d_name.len > NAME_MAX) { 208 unlock_kernel(); 209 return ERR_PTR(-ENAMETOOLONG);/* File name too long to exist */ 210 } 211 212 sbi = autofs_sbi(dir->i_sb); 213 214 oz_mode = autofs_oz_mode(sbi); 215 DPRINTK(("autofs_lookup: pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d\n", 216 current->pid, process_group(current), sbi->catatonic, oz_mode)); 217 218 /* 219 * Mark the dentry incomplete, but add it. This is needed so 220 * that the VFS layer knows about the dentry, and we can count 221 * on catching any lookups through the revalidate. 222 * 223 * Let all the hard work be done by the revalidate function that 224 * needs to be able to do this anyway.. 225 * 226 * We need to do this before we release the directory semaphore. 227 */ 228 dentry->d_op = &autofs_dentry_operations; 229 dentry->d_flags |= DCACHE_AUTOFS_PENDING; 230 d_add(dentry, NULL); 231 232 up(&dir->i_sem); 233 autofs_revalidate(dentry, nd); 234 down(&dir->i_sem); 235 236 /* 237 * If we are still pending, check if we had to handle 238 * a signal. If so we can force a restart.. 239 */ 240 if (dentry->d_flags & DCACHE_AUTOFS_PENDING) { 241 /* See if we were interrupted */ 242 if (signal_pending(current)) { 243 sigset_t *sigset = ¤t->pending.signal; 244 if (sigismember (sigset, SIGKILL) || 245 sigismember (sigset, SIGQUIT) || 246 sigismember (sigset, SIGINT)) { 247 unlock_kernel(); 248 return ERR_PTR(-ERESTARTNOINTR); 249 } 250 } 251 } 252 unlock_kernel(); 253 254 /* 255 * If this dentry is unhashed, then we shouldn't honour this 256 * lookup even if the dentry is positive. Returning ENOENT here 257 * doesn't do the right thing for all system calls, but it should 258 * be OK for the operations we permit from an autofs. 259 */ 260 if ( dentry->d_inode && d_unhashed(dentry) ) 261 return ERR_PTR(-ENOENT); 262 263 return NULL; 264 } 265 266 static int autofs_root_symlink(struct inode *dir, struct dentry *dentry, const char *symname) 267 { 268 struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb); 269 struct autofs_dirhash *dh = &sbi->dirhash; 270 struct autofs_dir_ent *ent; 271 unsigned int n; 272 int slsize; 273 struct autofs_symlink *sl; 274 275 DPRINTK(("autofs_root_symlink: %s <- ", symname)); 276 autofs_say(dentry->d_name.name,dentry->d_name.len); 277 278 lock_kernel(); 279 if ( !autofs_oz_mode(sbi) ) { 280 unlock_kernel(); 281 return -EACCES; 282 } 283 284 if ( autofs_hash_lookup(dh, &dentry->d_name) ) { 285 unlock_kernel(); 286 return -EEXIST; 287 } 288 289 n = find_first_zero_bit(sbi->symlink_bitmap,AUTOFS_MAX_SYMLINKS); 290 if ( n >= AUTOFS_MAX_SYMLINKS ) { 291 unlock_kernel(); 292 return -ENOSPC; 293 } 294 295 set_bit(n,sbi->symlink_bitmap); 296 sl = &sbi->symlink[n]; 297 sl->len = strlen(symname); 298 sl->data = kmalloc(slsize = sl->len+1, GFP_KERNEL); 299 if ( !sl->data ) { 300 clear_bit(n,sbi->symlink_bitmap); 301 unlock_kernel(); 302 return -ENOSPC; 303 } 304 305 ent = kmalloc(sizeof(struct autofs_dir_ent), GFP_KERNEL); 306 if ( !ent ) { 307 kfree(sl->data); 308 clear_bit(n,sbi->symlink_bitmap); 309 unlock_kernel(); 310 return -ENOSPC; 311 } 312 313 ent->name = kmalloc(dentry->d_name.len+1, GFP_KERNEL); 314 if ( !ent->name ) { 315 kfree(sl->data); 316 kfree(ent); 317 clear_bit(n,sbi->symlink_bitmap); 318 unlock_kernel(); 319 return -ENOSPC; 320 } 321 322 memcpy(sl->data,symname,slsize); 323 sl->mtime = get_seconds(); 324 325 ent->ino = AUTOFS_FIRST_SYMLINK + n; 326 ent->hash = dentry->d_name.hash; 327 memcpy(ent->name, dentry->d_name.name, 1+(ent->len = dentry->d_name.len)); 328 ent->dentry = NULL; /* We don't keep the dentry for symlinks */ 329 330 autofs_hash_insert(dh,ent); 331 d_instantiate(dentry, iget(dir->i_sb,ent->ino)); 332 unlock_kernel(); 333 return 0; 334 } 335 336 /* 337 * NOTE! 338 * 339 * Normal filesystems would do a "d_delete()" to tell the VFS dcache 340 * that the file no longer exists. However, doing that means that the 341 * VFS layer can turn the dentry into a negative dentry, which we 342 * obviously do not want (we're dropping the entry not because it 343 * doesn't exist, but because it has timed out). 344 * 345 * Also see autofs_root_rmdir().. 346 */ 347 static int autofs_root_unlink(struct inode *dir, struct dentry *dentry) 348 { 349 struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb); 350 struct autofs_dirhash *dh = &sbi->dirhash; 351 struct autofs_dir_ent *ent; 352 unsigned int n; 353 354 /* This allows root to remove symlinks */ 355 lock_kernel(); 356 if ( !autofs_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) ) { 357 unlock_kernel(); 358 return -EACCES; 359 } 360 361 ent = autofs_hash_lookup(dh, &dentry->d_name); 362 if ( !ent ) { 363 unlock_kernel(); 364 return -ENOENT; 365 } 366 367 n = ent->ino - AUTOFS_FIRST_SYMLINK; 368 if ( n >= AUTOFS_MAX_SYMLINKS ) { 369 unlock_kernel(); 370 return -EISDIR; /* It's a directory, dummy */ 371 } 372 if ( !test_bit(n,sbi->symlink_bitmap) ) { 373 unlock_kernel(); 374 return -EINVAL; /* Nonexistent symlink? Shouldn't happen */ 375 } 376 377 dentry->d_time = (unsigned long)(struct autofs_dirhash *)NULL; 378 autofs_hash_delete(ent); 379 clear_bit(n,sbi->symlink_bitmap); 380 kfree(sbi->symlink[n].data); 381 d_drop(dentry); 382 383 unlock_kernel(); 384 return 0; 385 } 386 387 static int autofs_root_rmdir(struct inode *dir, struct dentry *dentry) 388 { 389 struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb); 390 struct autofs_dirhash *dh = &sbi->dirhash; 391 struct autofs_dir_ent *ent; 392 393 lock_kernel(); 394 if ( !autofs_oz_mode(sbi) ) { 395 unlock_kernel(); 396 return -EACCES; 397 } 398 399 ent = autofs_hash_lookup(dh, &dentry->d_name); 400 if ( !ent ) { 401 unlock_kernel(); 402 return -ENOENT; 403 } 404 405 if ( (unsigned int)ent->ino < AUTOFS_FIRST_DIR_INO ) { 406 unlock_kernel(); 407 return -ENOTDIR; /* Not a directory */ 408 } 409 410 if ( ent->dentry != dentry ) { 411 printk("autofs_rmdir: odentry != dentry for entry %s\n", dentry->d_name.name); 412 } 413 414 dentry->d_time = (unsigned long)(struct autofs_dir_ent *)NULL; 415 autofs_hash_delete(ent); 416 dir->i_nlink--; 417 d_drop(dentry); 418 unlock_kernel(); 419 420 return 0; 421 } 422 423 static int autofs_root_mkdir(struct inode *dir, struct dentry *dentry, int mode) 424 { 425 struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb); 426 struct autofs_dirhash *dh = &sbi->dirhash; 427 struct autofs_dir_ent *ent; 428 ino_t ino; 429 430 lock_kernel(); 431 if ( !autofs_oz_mode(sbi) ) { 432 unlock_kernel(); 433 return -EACCES; 434 } 435 436 ent = autofs_hash_lookup(dh, &dentry->d_name); 437 if ( ent ) { 438 unlock_kernel(); 439 return -EEXIST; 440 } 441 442 if ( sbi->next_dir_ino < AUTOFS_FIRST_DIR_INO ) { 443 printk("autofs: Out of inode numbers -- what the heck did you do??\n"); 444 unlock_kernel(); 445 return -ENOSPC; 446 } 447 ino = sbi->next_dir_ino++; 448 449 ent = kmalloc(sizeof(struct autofs_dir_ent), GFP_KERNEL); 450 if ( !ent ) { 451 unlock_kernel(); 452 return -ENOSPC; 453 } 454 455 ent->name = kmalloc(dentry->d_name.len+1, GFP_KERNEL); 456 if ( !ent->name ) { 457 kfree(ent); 458 unlock_kernel(); 459 return -ENOSPC; 460 } 461 462 ent->hash = dentry->d_name.hash; 463 memcpy(ent->name, dentry->d_name.name, 1+(ent->len = dentry->d_name.len)); 464 ent->ino = ino; 465 ent->dentry = dentry; 466 autofs_hash_insert(dh,ent); 467 468 dir->i_nlink++; 469 d_instantiate(dentry, iget(dir->i_sb,ino)); 470 unlock_kernel(); 471 472 return 0; 473 } 474 475 /* Get/set timeout ioctl() operation */ 476 static inline int autofs_get_set_timeout(struct autofs_sb_info *sbi, 477 unsigned long __user *p) 478 { 479 unsigned long ntimeout; 480 481 if (get_user(ntimeout, p) || 482 put_user(sbi->exp_timeout / HZ, p)) 483 return -EFAULT; 484 485 if ( ntimeout > ULONG_MAX/HZ ) 486 sbi->exp_timeout = 0; 487 else 488 sbi->exp_timeout = ntimeout * HZ; 489 490 return 0; 491 } 492 493 /* Return protocol version */ 494 static inline int autofs_get_protover(int __user *p) 495 { 496 return put_user(AUTOFS_PROTO_VERSION, p); 497 } 498 499 /* Perform an expiry operation */ 500 static inline int autofs_expire_run(struct super_block *sb, 501 struct autofs_sb_info *sbi, 502 struct vfsmount *mnt, 503 struct autofs_packet_expire __user *pkt_p) 504 { 505 struct autofs_dir_ent *ent; 506 struct autofs_packet_expire pkt; 507 508 memset(&pkt,0,sizeof pkt); 509 510 pkt.hdr.proto_version = AUTOFS_PROTO_VERSION; 511 pkt.hdr.type = autofs_ptype_expire; 512 513 if ( !sbi->exp_timeout || 514 !(ent = autofs_expire(sb,sbi,mnt)) ) 515 return -EAGAIN; 516 517 pkt.len = ent->len; 518 memcpy(pkt.name, ent->name, pkt.len); 519 pkt.name[pkt.len] = '\0'; 520 521 if ( copy_to_user(pkt_p, &pkt, sizeof(struct autofs_packet_expire)) ) 522 return -EFAULT; 523 524 return 0; 525 } 526 527 /* 528 * ioctl()'s on the root directory is the chief method for the daemon to 529 * generate kernel reactions 530 */ 531 static int autofs_root_ioctl(struct inode *inode, struct file *filp, 532 unsigned int cmd, unsigned long arg) 533 { 534 struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb); 535 void __user *argp = (void __user *)arg; 536 537 DPRINTK(("autofs_ioctl: cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n",cmd,arg,sbi,process_group(current))); 538 539 if ( _IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) || 540 _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT ) 541 return -ENOTTY; 542 543 if ( !autofs_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) ) 544 return -EPERM; 545 546 switch(cmd) { 547 case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */ 548 return autofs_wait_release(sbi,(autofs_wqt_t)arg,0); 549 case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */ 550 return autofs_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT); 551 case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */ 552 autofs_catatonic_mode(sbi); 553 return 0; 554 case AUTOFS_IOC_PROTOVER: /* Get protocol version */ 555 return autofs_get_protover(argp); 556 case AUTOFS_IOC_SETTIMEOUT: 557 return autofs_get_set_timeout(sbi, argp); 558 case AUTOFS_IOC_EXPIRE: 559 return autofs_expire_run(inode->i_sb, sbi, filp->f_vfsmnt, 560 argp); 561 default: 562 return -ENOSYS; 563 } 564 } 565