1 /* ufs_vnops.c 4.56 83/05/21 */ 2 3 #include "../h/param.h" 4 #include "../h/systm.h" 5 #include "../h/dir.h" 6 #include "../h/user.h" 7 #include "../h/kernel.h" 8 #include "../h/file.h" 9 #include "../h/stat.h" 10 #include "../h/inode.h" 11 #include "../h/fs.h" 12 #include "../h/buf.h" 13 #include "../h/proc.h" 14 #include "../h/quota.h" 15 #include "../h/descrip.h" 16 #include "../h/uio.h" 17 #include "../h/socket.h" 18 #include "../h/socketvar.h" 19 #include "../h/nami.h" 20 21 /* 22 * Change current working directory (``.''). 23 */ 24 chdir() 25 { 26 27 chdirec(&u.u_cdir); 28 } 29 30 /* 31 * Change notion of root (``/'') directory. 32 */ 33 chroot() 34 { 35 36 if (suser()) 37 chdirec(&u.u_rdir); 38 } 39 40 /* 41 * Common routine for chroot and chdir. 42 */ 43 chdirec(ipp) 44 register struct inode **ipp; 45 { 46 register struct inode *ip; 47 struct a { 48 char *fname; 49 }; 50 51 ip = namei(uchar, LOOKUP, 1); 52 if (ip == NULL) 53 return; 54 if ((ip->i_mode&IFMT) != IFDIR) { 55 u.u_error = ENOTDIR; 56 goto bad; 57 } 58 if (access(ip, IEXEC)) 59 goto bad; 60 iunlock(ip); 61 if (*ipp) 62 irele(*ipp); 63 *ipp = ip; 64 return; 65 66 bad: 67 iput(ip); 68 } 69 70 /* 71 * Open system call. 72 */ 73 open() 74 { 75 register struct inode *ip; 76 register struct a { 77 char *fname; 78 int flags; 79 int mode; 80 } *uap; 81 int checkpermissions = 1, flags; 82 83 uap = (struct a *)u.u_ap; 84 flags = uap->flags + 1; 85 if ((flags&FTRUNCATE) && (flags&FWRITE) == 0) { 86 u.u_error = EINVAL; 87 return; 88 } 89 if (flags&FCREATE) { 90 ip = namei(uchar, CREATE, 1); 91 if (ip == NULL) { 92 if (u.u_error) 93 return; 94 ip = maknode(uap->mode&07777&(~ISVTX)); 95 checkpermissions = 0; 96 flags &= ~FTRUNCATE; 97 } 98 } else 99 ip = namei(uchar, LOOKUP, 1); 100 if (ip == NULL) 101 return; 102 open1(ip, flags, checkpermissions); 103 } 104 105 #ifndef NOCOMPAT 106 /* 107 * Creat system call. 108 */ 109 ocreat() 110 { 111 register struct inode *ip; 112 register struct a { 113 char *fname; 114 int fmode; 115 } *uap; 116 117 uap = (struct a *)u.u_ap; 118 ip = namei(uchar, CREATE, 1); 119 if (ip == NULL) { 120 if (u.u_error) 121 return; 122 ip = maknode(uap->fmode&07777&(~ISVTX)); 123 if (ip == NULL) 124 return; 125 open1(ip, FWRITE, 0); 126 } else 127 open1(ip, FWRITE|FTRUNCATE, 1); 128 } 129 #endif 130 131 /* 132 * Common code for open and creat. 133 * Check permissions (if we haven't done so already), 134 * allocate an open file structure, and call 135 * the device open routine, if any. 136 */ 137 open1(ip, mode, checkpermissions) 138 register struct inode *ip; 139 register mode; 140 { 141 register struct file *fp; 142 int i, flags; 143 144 if (checkpermissions) { 145 if (mode&FREAD) 146 if (access(ip, IREAD)) 147 goto bad; 148 if (mode&FWRITE) { 149 if (access(ip, IWRITE)) 150 goto bad; 151 if ((ip->i_mode&IFMT) == IFDIR) { 152 u.u_error = EISDIR; 153 goto bad; 154 } 155 } 156 } 157 158 /* 159 * Check locking on inode. Release "inode lock" 160 * while doing so in case we block inside flocki. 161 */ 162 flags = 0; 163 if (mode&(FSHLOCK|FEXLOCK)) { 164 iunlock(ip); 165 flags = flocki(ip, 0, mode); 166 ilock(ip); 167 if (u.u_error) 168 goto bad; 169 } 170 if (mode&FTRUNCATE) 171 itrunc(ip, (u_long)0); 172 iunlock(ip); 173 if ((fp = falloc()) == NULL) 174 goto out; 175 fp->f_flag = mode & FMODES; 176 fp->f_type = DTYPE_FILE; 177 i = u.u_r.r_val1; 178 fp->f_inode = ip; 179 u.u_error = openi(ip, mode); 180 if (u.u_error == 0) { 181 u.u_pofile[i] = flags; 182 return; 183 } 184 u.u_ofile[i] = NULL; 185 fp->f_count--; 186 out: 187 irele(ip); 188 return; 189 bad: 190 iput(ip); 191 } 192 193 /* 194 * Mknod system call 195 */ 196 mknod() 197 { 198 register struct inode *ip; 199 register struct a { 200 char *fname; 201 int fmode; 202 int dev; 203 } *uap; 204 205 uap = (struct a *)u.u_ap; 206 if (suser()) { 207 ip = namei(uchar, CREATE, 0); 208 if (ip != NULL) { 209 u.u_error = EEXIST; 210 goto out; 211 } 212 } 213 if (u.u_error) 214 return; 215 ip = maknode(uap->fmode); 216 if (ip == NULL) 217 return; 218 if (uap->dev) { 219 /* 220 * Want to be able to use this to make badblock 221 * inodes, so don't truncate the dev number. 222 */ 223 ip->i_rdev = uap->dev; 224 ip->i_flag |= IACC|IUPD|ICHG; 225 } 226 227 out: 228 iput(ip); 229 } 230 231 /* 232 * link system call 233 */ 234 link() 235 { 236 register struct inode *ip, *xp; 237 register struct a { 238 char *target; 239 char *linkname; 240 } *uap; 241 242 uap = (struct a *)u.u_ap; 243 ip = namei(uchar, LOOKUP, 1); /* well, this routine is doomed anyhow */ 244 if (ip == NULL) 245 return; 246 if ((ip->i_mode&IFMT) == IFDIR && !suser()) { 247 iput(ip); 248 return; 249 } 250 ip->i_nlink++; 251 ip->i_flag |= ICHG; 252 iupdat(ip, &time, &time, 1); 253 iunlock(ip); 254 u.u_dirp = (caddr_t)uap->linkname; 255 xp = namei(uchar, CREATE, 0); 256 if (xp != NULL) { 257 u.u_error = EEXIST; 258 iput(xp); 259 goto out; 260 } 261 if (u.u_error) 262 goto out; 263 if (u.u_pdir->i_dev != ip->i_dev) { 264 iput(u.u_pdir); 265 u.u_error = EXDEV; 266 goto out; 267 } 268 u.u_error = direnter(ip); 269 out: 270 if (u.u_error) { 271 ip->i_nlink--; 272 ip->i_flag |= ICHG; 273 } 274 irele(ip); 275 } 276 277 /* 278 * symlink -- make a symbolic link 279 */ 280 symlink() 281 { 282 register struct a { 283 char *target; 284 char *linkname; 285 } *uap; 286 register struct inode *ip; 287 register char *tp; 288 register c, nc; 289 290 uap = (struct a *)u.u_ap; 291 tp = uap->target; 292 nc = 0; 293 while (c = fubyte(tp)) { 294 if (c < 0) { 295 u.u_error = EFAULT; 296 return; 297 } 298 tp++; 299 nc++; 300 } 301 u.u_dirp = uap->linkname; 302 ip = namei(uchar, CREATE, 0); 303 if (ip) { 304 iput(ip); 305 u.u_error = EEXIST; 306 return; 307 } 308 if (u.u_error) 309 return; 310 ip = maknode(IFLNK | 0777); 311 if (ip == NULL) 312 return; 313 u.u_error = rdwri(UIO_WRITE, ip, uap->target, nc, 0, 0, (int *)0); 314 /* handle u.u_error != 0 */ 315 iput(ip); 316 } 317 318 /* 319 * Unlink system call. 320 * Hard to avoid races here, especially 321 * in unlinking directories. 322 */ 323 unlink() 324 { 325 struct a { 326 char *fname; 327 }; 328 register struct inode *ip, *dp; 329 330 ip = namei(uchar, DELETE | LOCKPARENT, 0); 331 if (ip == NULL) 332 return; 333 dp = u.u_pdir; 334 if ((ip->i_mode&IFMT) == IFDIR && !suser()) 335 goto out; 336 /* 337 * Don't unlink a mounted file. 338 */ 339 if (ip->i_dev != dp->i_dev) { 340 u.u_error = EBUSY; 341 goto out; 342 } 343 if (ip->i_flag&ITEXT) 344 xrele(ip); /* try once to free text */ 345 if (dirremove()) { 346 ip->i_nlink--; 347 ip->i_flag |= ICHG; 348 } 349 out: 350 if (dp == ip) 351 irele(ip); 352 else 353 iput(ip); 354 iput(dp); 355 } 356 357 /* 358 * Seek system call 359 */ 360 lseek() 361 { 362 register struct file *fp; 363 register struct a { 364 int fd; 365 off_t off; 366 int sbase; 367 } *uap; 368 369 uap = (struct a *)u.u_ap; 370 fp = getf(uap->fd); 371 if (fp == NULL) 372 return; 373 if (fp->f_type == DTYPE_SOCKET) { 374 u.u_error = ESPIPE; 375 return; 376 } 377 if (uap->sbase == FSEEK_RELATIVE) 378 uap->off += fp->f_offset; 379 else if (uap->sbase == FSEEK_EOF) 380 uap->off += fp->f_inode->i_size; 381 fp->f_offset = uap->off; 382 u.u_r.r_off = uap->off; 383 } 384 385 /* 386 * Access system call 387 */ 388 saccess() 389 { 390 register svuid, svgid; 391 register struct inode *ip; 392 register struct a { 393 char *fname; 394 int fmode; 395 } *uap; 396 397 uap = (struct a *)u.u_ap; 398 svuid = u.u_uid; 399 svgid = u.u_gid; 400 u.u_uid = u.u_ruid; 401 u.u_gid = u.u_rgid; 402 ip = namei(uchar, LOOKUP, 1); 403 if (ip != NULL) { 404 if ((uap->fmode&FACCESS_READ) && access(ip, IREAD)) 405 goto done; 406 if ((uap->fmode&FACCESS_WRITE) && access(ip, IWRITE)) 407 goto done; 408 if ((uap->fmode&FACCESS_EXECUTE) && access(ip, IEXEC)) 409 goto done; 410 done: 411 iput(ip); 412 } 413 u.u_uid = svuid; 414 u.u_gid = svgid; 415 } 416 417 /* 418 * the fstat system call. 419 */ 420 fstat() 421 { 422 register struct file *fp; 423 register struct a { 424 int fd; 425 struct stat *sb; 426 } *uap; 427 428 uap = (struct a *)u.u_ap; 429 fp = getf(uap->fd); 430 if (fp == NULL) 431 return; 432 if (fp->f_type == DTYPE_SOCKET) 433 u.u_error = sostat(fp->f_socket, uap->sb); 434 else 435 stat1(fp->f_inode, uap->sb); 436 } 437 438 /* 439 * Stat system call. This version follows links. 440 */ 441 stat() 442 { 443 register struct inode *ip; 444 register struct a { 445 char *fname; 446 struct stat *sb; 447 } *uap; 448 449 uap = (struct a *)u.u_ap; 450 ip = namei(uchar, LOOKUP, 1); 451 if (ip == NULL) 452 return; 453 stat1(ip, uap->sb); 454 iput(ip); 455 } 456 457 /* 458 * Lstat system call. This version does not follow links. 459 */ 460 lstat() 461 { 462 register struct inode *ip; 463 register struct a { 464 char *fname; 465 struct stat *sb; 466 } *uap; 467 468 uap = (struct a *)u.u_ap; 469 ip = namei(uchar, LOOKUP, 0); 470 if (ip == NULL) 471 return; 472 stat1(ip, uap->sb); 473 iput(ip); 474 } 475 476 /* 477 * The basic routine for fstat and stat: 478 * get the inode and pass appropriate parts back. 479 */ 480 stat1(ip, ub) 481 register struct inode *ip; 482 struct stat *ub; 483 { 484 struct stat ds; 485 486 IUPDAT(ip, &time, &time, 0); 487 /* 488 * Copy from inode table 489 */ 490 ds.st_dev = ip->i_dev; 491 ds.st_ino = ip->i_number; 492 ds.st_mode = ip->i_mode; 493 ds.st_nlink = ip->i_nlink; 494 ds.st_uid = ip->i_uid; 495 ds.st_gid = ip->i_gid; 496 ds.st_rdev = (dev_t)ip->i_rdev; 497 ds.st_size = ip->i_size; 498 ds.st_atime = ip->i_atime; 499 ds.st_spare1 = 0; 500 ds.st_mtime = ip->i_mtime; 501 ds.st_spare2 = 0; 502 ds.st_ctime = ip->i_ctime; 503 ds.st_spare3 = 0; 504 /* this doesn't belong here */ 505 if ((ip->i_mode&IFMT) == IFBLK) 506 ds.st_blksize = BLKDEV_IOSIZE; 507 else if ((ip->i_mode&IFMT) == IFCHR) 508 ds.st_blksize = MAXBSIZE; 509 else 510 ds.st_blksize = ip->i_fs->fs_bsize; 511 ds.st_blocks = ip->i_blocks; 512 ds.st_spare4[0] = ds.st_spare4[1] = 0; 513 u.u_error = copyout((caddr_t)&ds, (caddr_t)ub, sizeof(ds)); 514 } 515 516 /* 517 * Return target name of a symbolic link 518 */ 519 readlink() 520 { 521 register struct inode *ip; 522 register struct a { 523 char *name; 524 char *buf; 525 int count; 526 } *uap = (struct a *)u.u_ap; 527 int resid; 528 529 ip = namei(uchar, LOOKUP, 0); 530 if (ip == NULL) 531 return; 532 if ((ip->i_mode&IFMT) != IFLNK) { 533 u.u_error = ENXIO; 534 goto out; 535 } 536 u.u_error = rdwri(UIO_READ, ip, uap->buf, uap->count, 0, 0, &resid); 537 out: 538 iput(ip); 539 u.u_r.r_val1 = uap->count - resid; 540 } 541 542 /* 543 * Change mode of a file given path name. 544 */ 545 chmod() 546 { 547 struct inode *ip; 548 struct a { 549 char *fname; 550 int fmode; 551 } *uap; 552 553 uap = (struct a *)u.u_ap; 554 if ((ip = owner(1)) == NULL) 555 return; 556 chmod1(ip, uap->fmode); 557 iput(ip); 558 } 559 560 /* 561 * Change mode of a file given a file descriptor. 562 */ 563 fchmod() 564 { 565 struct a { 566 int fd; 567 int fmode; 568 } *uap; 569 register struct inode *ip; 570 register struct file *fp; 571 572 uap = (struct a *)u.u_ap; 573 fp = getf(uap->fd); 574 if (fp == NULL) 575 return; 576 if (fp->f_type == DTYPE_SOCKET) { 577 u.u_error = EINVAL; 578 return; 579 } 580 ip = fp->f_inode; 581 if (u.u_uid != ip->i_uid && !suser()) 582 return; 583 ilock(ip); 584 chmod1(ip, uap->fmode); 585 iunlock(ip); 586 } 587 588 /* 589 * Change the mode on a file. 590 * Inode must be locked before calling. 591 */ 592 chmod1(ip, mode) 593 register struct inode *ip; 594 register int mode; 595 { 596 register int *gp; 597 598 ip->i_mode &= ~07777; 599 if (u.u_uid) { 600 mode &= ~ISVTX; 601 if (!groupmember(ip->i_gid)) 602 mode &= ~ISGID; 603 } 604 ip->i_mode |= mode&07777; 605 ip->i_flag |= ICHG; 606 if (ip->i_flag&ITEXT && (ip->i_mode&ISVTX)==0) 607 xrele(ip); 608 } 609 610 /* 611 * Set ownership given a path name. 612 */ 613 chown() 614 { 615 struct inode *ip; 616 struct a { 617 char *fname; 618 int uid; 619 int gid; 620 } *uap; 621 622 uap = (struct a *)u.u_ap; 623 if (!suser() || (ip = owner(0)) == NULL) 624 return; 625 u.u_error = chown1(ip, uap->uid, uap->gid); 626 iput(ip); 627 } 628 629 /* 630 * Set ownership given a file descriptor. 631 */ 632 fchown() 633 { 634 struct a { 635 int fd; 636 int uid; 637 int gid; 638 } *uap; 639 register struct inode *ip; 640 register struct file *fp; 641 642 uap = (struct a *)u.u_ap; 643 fp = getf(uap->fd); 644 if (fp == NULL) 645 return; 646 if (fp->f_type == DTYPE_SOCKET) { 647 u.u_error = EINVAL; 648 return; 649 } 650 ip = fp->f_inode; 651 if (!suser()) 652 return; 653 ilock(ip); 654 u.u_error = chown1(ip, uap->uid, uap->gid); 655 iunlock(ip); 656 } 657 658 /* 659 * Perform chown operation on inode ip; 660 * inode must be locked prior to call. 661 */ 662 chown1(ip, uid, gid) 663 register struct inode *ip; 664 int uid, gid; 665 { 666 #ifdef QUOTA 667 register long change; 668 #endif 669 670 if (uid == -1) 671 uid = ip->i_uid; 672 if (gid == -1) 673 gid = ip->i_gid; 674 #ifdef QUOTA 675 if (ip->i_uid != uid) /* this just speeds things a little */ 676 change = 0; 677 else 678 change = ip->i_blocks; 679 (void) chkdq(ip, -change, 1); 680 (void) chkiq(ip->i_dev, ip, ip->i_uid, 1); 681 dqrele(ip->i_dquot); 682 #endif 683 ip->i_uid = uid; 684 ip->i_gid = gid; 685 ip->i_flag |= ICHG; 686 if (u.u_ruid != 0) 687 ip->i_mode &= ~(ISUID|ISGID); 688 #ifdef QUOTA 689 ip->i_dquot = inoquota(ip); 690 (void) chkdq(ip, change, 1); 691 (void) chkiq(ip->i_dev, (struct inode *)NULL, uid, 1); 692 return (u.u_error); /* should == 0 ALWAYS !! */ 693 #else 694 return (0); 695 #endif 696 } 697 698 #ifndef NOCOMPAT 699 /* 700 * Set IUPD and IACC times on file. 701 * Can't set ICHG. 702 */ 703 outime() 704 { 705 register struct a { 706 char *fname; 707 time_t *tptr; 708 } *uap = (struct a *)u.u_ap; 709 register struct inode *ip; 710 time_t tv[2]; 711 struct timeval tv0, tv1; 712 713 if ((ip = owner(1)) == NULL) 714 return; 715 u.u_error = copyin((caddr_t)uap->tptr, (caddr_t)tv, sizeof (tv)); 716 if (u.u_error == 0) { 717 ip->i_flag |= IACC|IUPD|ICHG; 718 tv0.tv_sec = tv[0]; tv0.tv_usec = 0; 719 tv1.tv_sec = tv[1]; tv1.tv_usec = 0; 720 iupdat(ip, &tv0, &tv1, 0); 721 } 722 iput(ip); 723 } 724 #endif 725 726 utimes() 727 { 728 register struct a { 729 char *fname; 730 struct timeval *tptr; 731 } *uap = (struct a *)u.u_ap; 732 register struct inode *ip; 733 struct timeval tv[2]; 734 735 if ((ip = owner(1)) == NULL) 736 return; 737 u.u_error = copyin((caddr_t)uap->tptr, (caddr_t)tv, sizeof (tv)); 738 if (u.u_error == 0) { 739 ip->i_flag |= IACC|IUPD|ICHG; 740 iupdat(ip, &tv[0], &tv[1], 0); 741 } 742 iput(ip); 743 } 744 745 /* 746 * Flush any pending I/O. 747 */ 748 sync() 749 { 750 751 update(); 752 } 753 754 /* 755 * Apply an advisory lock on a file descriptor. 756 */ 757 flock() 758 { 759 struct a { 760 int fd; 761 int how; 762 } *uap; 763 register struct file *fp; 764 register int cmd, flags; 765 766 uap = (struct a *)u.u_ap; 767 fp = getf(uap->fd); 768 if (fp == NULL) 769 return; 770 if (fp->f_type == DTYPE_SOCKET) { /* XXX */ 771 u.u_error = EINVAL; 772 return; 773 } 774 cmd = uap->how; 775 flags = u.u_pofile[uap->fd] & (UF_SHLOCK|UF_EXLOCK); 776 if (cmd&FUNLOCK) { 777 if (flags == 0) { 778 u.u_error = EINVAL; 779 return; 780 } 781 funlocki(fp->f_inode, flags); 782 u.u_pofile[uap->fd] &= ~(UF_SHLOCK|UF_EXLOCK); 783 return; 784 } 785 /* 786 * No reason to write lock a file we've already 787 * write locked, similarly with a read lock. 788 */ 789 if ((flags&UF_EXLOCK) && (cmd&FEXLOCK) || 790 (flags&UF_SHLOCK) && (cmd&FSHLOCK)) 791 return; 792 u.u_pofile[uap->fd] = flocki(fp->f_inode, u.u_pofile[uap->fd], cmd); 793 } 794 795 /* 796 * Truncate a file given its path name. 797 */ 798 truncate() 799 { 800 struct a { 801 char *fname; 802 u_long length; 803 } *uap = (struct a *)u.u_ap; 804 struct inode *ip; 805 806 ip = namei(uchar, LOOKUP, 1); 807 if (ip == NULL) 808 return; 809 if (access(ip, IWRITE)) 810 goto bad; 811 if ((ip->i_mode&IFMT) == IFDIR) { 812 u.u_error = EISDIR; 813 goto bad; 814 } 815 itrunc(ip, uap->length); 816 bad: 817 iput(ip); 818 } 819 820 /* 821 * Truncate a file given a file descriptor. 822 */ 823 ftruncate() 824 { 825 struct a { 826 int fd; 827 u_long length; 828 } *uap = (struct a *)u.u_ap; 829 struct inode *ip; 830 struct file *fp; 831 832 fp = getf(uap->fd); 833 if (fp == NULL) 834 return; 835 if (fp->f_type == DTYPE_SOCKET) { 836 u.u_error = EINVAL; 837 return; 838 } 839 if ((fp->f_flag&FWRITE) == 0) { 840 u.u_error = EINVAL; 841 return; 842 } 843 ip = fp->f_inode; 844 ilock(ip); 845 itrunc(ip, uap->length); 846 iunlock(ip); 847 } 848 849 /* 850 * Synch an open file. 851 */ 852 fsync() 853 { 854 struct a { 855 int fd; 856 } *uap = (struct a *)u.u_ap; 857 struct inode *ip; 858 struct file *fp; 859 860 fp = getf(uap->fd); 861 if (fp == NULL) 862 return; 863 if (fp->f_type == DTYPE_SOCKET) { 864 u.u_error = EINVAL; 865 return; 866 } 867 ip = fp->f_inode; 868 ilock(ip); 869 syncip(ip); 870 iunlock(ip); 871 } 872 873 /* 874 * Rename system call. 875 * rename("foo", "bar"); 876 * is essentially 877 * unlink("bar"); 878 * link("foo", "bar"); 879 * unlink("foo"); 880 * but ``atomically''. Can't do full commit without saving state in the 881 * inode on disk which isn't feasible at this time. Best we can do is 882 * always guarantee the target exists. 883 * 884 * Basic algorithm is: 885 * 886 * 1) Bump link count on source while we're linking it to the 887 * target. This also insure the inode won't be deleted out 888 * from underneath us while we work. 889 * 2) Link source to destination. If destination already exists, 890 * delete it first. 891 * 3) Unlink source reference to inode if still around. 892 * 4) If a directory was moved and the parent of the destination 893 * is different from the source, patch the ".." entry in the 894 * directory. 895 * 896 * Source and destination must either both be directories, or both 897 * not be directories. If target is a directory, it must be empty. 898 */ 899 rename() 900 { 901 struct a { 902 char *from; 903 char *to; 904 } *uap; 905 register struct inode *ip, *xp, *dp; 906 int oldparent, parentdifferent, doingdirectory; 907 int error = 0; 908 909 uap = (struct a *)u.u_ap; 910 ip = namei(uchar, DELETE | LOCKPARENT, 0); 911 if (ip == NULL) 912 return; 913 dp = u.u_pdir; 914 oldparent = 0, doingdirectory = 0; 915 if ((ip->i_mode&IFMT) == IFDIR) { 916 register struct direct *d; 917 918 d = &u.u_dent; 919 /* 920 * Avoid ".", "..", and aliases of "." for obvious reasons. 921 */ 922 if ((d->d_namlen == 1 && d->d_name[0] == '.') || 923 (d->d_namlen == 2 && bcmp(d->d_name, "..", 2) == 0) || 924 (dp == ip)) { 925 iput(dp); 926 if (dp == ip) 927 irele(ip); 928 else 929 iput(ip); 930 u.u_error = EINVAL; 931 return; 932 } 933 oldparent = dp->i_number; 934 doingdirectory++; 935 } 936 iput(dp); 937 938 /* 939 * 1) Bump link count while we're moving stuff 940 * around. If we crash somewhere before 941 * completing our work, the link count 942 * may be wrong, but correctable. 943 */ 944 ip->i_nlink++; 945 ip->i_flag |= ICHG; 946 iupdat(ip, &time, &time, 1); 947 iunlock(ip); 948 949 /* 950 * When the target exists, both the directory 951 * and target inodes are returned locked. 952 */ 953 u.u_dirp = (caddr_t)uap->to; 954 xp = namei(uchar, CREATE | LOCKPARENT, 0); 955 if (u.u_error) { 956 error = u.u_error; 957 goto out; 958 } 959 dp = u.u_pdir; 960 /* 961 * If ".." must be changed (ie the directory gets a new 962 * parent) then the user must have write permission. 963 */ 964 parentdifferent = oldparent != dp->i_number; 965 if (doingdirectory && parentdifferent && access(ip, IWRITE)) 966 goto bad; 967 /* 968 * 2) If target doesn't exist, link the target 969 * to the source and unlink the source. 970 * Otherwise, rewrite the target directory 971 * entry to reference the source inode and 972 * expunge the original entry's existence. 973 */ 974 if (xp == NULL) { 975 if (dp->i_dev != ip->i_dev) { 976 error = EXDEV; 977 goto bad; 978 } 979 /* 980 * Disallow rename(foo, foo/bar). 981 */ 982 if (dp->i_number == ip->i_number) { 983 error = EEXIST; 984 goto bad; 985 } 986 /* 987 * Account for ".." in directory. 988 * When source and destination have the 989 * same parent we don't fool with the 990 * link count -- this isn't required 991 * because we do a similar check below. 992 */ 993 if (doingdirectory && parentdifferent) { 994 dp->i_nlink++; 995 dp->i_flag |= ICHG; 996 iupdat(dp, &time, &time, 1); 997 } 998 error = direnter(ip); 999 if (error) 1000 goto out; 1001 } else { 1002 if (xp->i_dev != dp->i_dev || xp->i_dev != ip->i_dev) { 1003 error = EXDEV; 1004 goto bad; 1005 } 1006 /* 1007 * Short circuit rename(foo, foo). 1008 */ 1009 if (xp->i_number == ip->i_number) 1010 goto bad; 1011 /* 1012 * Target must be empty if a directory 1013 * and have no links to it. 1014 * Also, insure source and target are 1015 * compatible (both directories, or both 1016 * not directories). 1017 */ 1018 if ((xp->i_mode&IFMT) == IFDIR) { 1019 if (!dirempty(xp) || xp->i_nlink > 2) { 1020 error = ENOTEMPTY; 1021 goto bad; 1022 } 1023 if (!doingdirectory) { 1024 error = ENOTDIR; 1025 goto bad; 1026 } 1027 } else if (doingdirectory) { 1028 error = EISDIR; 1029 goto bad; 1030 } 1031 dirrewrite(dp, ip); 1032 if (u.u_error) { 1033 error = u.u_error; 1034 goto bad1; 1035 } 1036 /* 1037 * Adjust the link count of the target to 1038 * reflect the dirrewrite above. If this is 1039 * a directory it is empty and there are 1040 * no links to it, so we can squash the inode and 1041 * any space associated with it. We disallowed 1042 * renaming over top of a directory with links to 1043 * it above, as we've no way to determine if 1044 * we've got a link or the directory itself, and 1045 * if we get a link, then ".." will be screwed up. 1046 */ 1047 xp->i_nlink--; 1048 if (doingdirectory) { 1049 if (--xp->i_nlink != 0) 1050 panic("rename: linked directory"); 1051 itrunc(xp, (u_long)0); 1052 } 1053 xp->i_flag |= ICHG; 1054 iput(xp); 1055 xp = NULL; 1056 } 1057 1058 /* 1059 * 3) Unlink the source. 1060 */ 1061 u.u_dirp = uap->from; 1062 dp = namei(uchar, DELETE, 0); 1063 /* 1064 * Insure directory entry still exists and 1065 * has not changed since the start of all 1066 * this. If either has occured, forget about 1067 * about deleting the original entry and just 1068 * adjust the link count in the inode. 1069 */ 1070 if (dp == NULL || u.u_dent.d_ino != ip->i_number) { 1071 ip->i_nlink--; 1072 ip->i_flag |= ICHG; 1073 } else { 1074 /* 1075 * If source is a directory, must adjust 1076 * link count of parent directory also. 1077 * If target didn't exist and source and 1078 * target have the same parent, then we 1079 * needn't touch the link count, it all 1080 * balances out in the end. Otherwise, we 1081 * must do so to reflect deletion of ".." 1082 * done above. 1083 */ 1084 if (doingdirectory && (xp != NULL || parentdifferent)) { 1085 dp->i_nlink--; 1086 dp->i_flag |= ICHG; 1087 } 1088 if (dirremove()) { 1089 ip->i_nlink--; 1090 ip->i_flag |= ICHG; 1091 } 1092 if (error == 0) /* conservative */ 1093 error = u.u_error; 1094 } 1095 irele(ip); 1096 if (dp) 1097 iput(dp); 1098 1099 /* 1100 * 4) Renaming a directory with the parent 1101 * different requires ".." to be rewritten. 1102 * The window is still there for ".." to 1103 * be inconsistent, but this is unavoidable, 1104 * and a lot shorter than when it was done 1105 * in a user process. 1106 */ 1107 if (doingdirectory && parentdifferent && error == 0) { 1108 struct dirtemplate dirbuf; 1109 1110 u.u_dirp = uap->to; 1111 ip = namei(uchar, LOOKUP | LOCKPARENT, 0); 1112 if (ip == NULL) { 1113 printf("rename: .. went away\n"); 1114 return; 1115 } 1116 dp = u.u_pdir; 1117 if ((ip->i_mode&IFMT) != IFDIR) { 1118 printf("rename: .. not a directory\n"); 1119 goto stuck; 1120 } 1121 error = rdwri(UIO_READ, ip, (caddr_t)&dirbuf, 1122 sizeof (struct dirtemplate), (off_t)0, 1, (int *)0); 1123 if (error == 0) { 1124 dirbuf.dotdot_ino = dp->i_number; 1125 (void) rdwri(UIO_WRITE, ip, (caddr_t)&dirbuf, 1126 sizeof (struct dirtemplate), (off_t)0, 1, (int *)0); 1127 } 1128 stuck: 1129 irele(dp); 1130 iput(ip); 1131 } 1132 goto done; 1133 1134 bad: 1135 iput(dp); 1136 bad1: 1137 if (xp) 1138 iput(xp); 1139 out: 1140 ip->i_nlink--; 1141 ip->i_flag |= ICHG; 1142 irele(ip); 1143 done: 1144 if (error) 1145 u.u_error = error; 1146 } 1147 1148 /* 1149 * Make a new file. 1150 */ 1151 struct inode * 1152 maknode(mode) 1153 int mode; 1154 { 1155 register struct inode *ip; 1156 ino_t ipref; 1157 1158 if ((mode & IFMT) == IFDIR) 1159 ipref = dirpref(u.u_pdir->i_fs); 1160 else 1161 ipref = u.u_pdir->i_number; 1162 ip = ialloc(u.u_pdir, ipref, mode); 1163 if (ip == NULL) { 1164 iput(u.u_pdir); 1165 return (NULL); 1166 } 1167 #ifdef QUOTA 1168 if (ip->i_dquot != NODQUOT) 1169 panic("maknode: dquot"); 1170 #endif 1171 ip->i_flag |= IACC|IUPD|ICHG; 1172 if ((mode & IFMT) == 0) 1173 mode |= IFREG; 1174 ip->i_mode = mode & ~u.u_cmask; 1175 ip->i_nlink = 1; 1176 ip->i_uid = u.u_uid; 1177 ip->i_gid = u.u_pdir->i_gid; 1178 if (ip->i_mode & ISGID && !groupmember(ip->i_gid)) 1179 ip->i_mode &= ~ISGID; 1180 #ifdef QUOTA 1181 ip->i_dquot = inoquota(ip); 1182 #endif 1183 1184 /* 1185 * Make sure inode goes to disk before directory entry. 1186 */ 1187 iupdat(ip, &time, &time, 1); 1188 u.u_error = direnter(ip); 1189 if (u.u_error) { 1190 /* 1191 * Write error occurred trying to update directory 1192 * so must deallocate the inode. 1193 */ 1194 ip->i_nlink = 0; 1195 ip->i_flag |= ICHG; 1196 iput(ip); 1197 return (NULL); 1198 } 1199 return (ip); 1200 } 1201