1 /* vfs_syscalls.c 4.51 83/02/20 */ 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_spare4[0] = ds.st_spare4[1] = ds.st_spare4[2] = 0; 512 u.u_error = copyout((caddr_t)&ds, (caddr_t)ub, sizeof(ds)); 513 } 514 515 /* 516 * Return target name of a symbolic link 517 */ 518 readlink() 519 { 520 register struct inode *ip; 521 register struct a { 522 char *name; 523 char *buf; 524 int count; 525 } *uap = (struct a *)u.u_ap; 526 int resid; 527 528 ip = namei(uchar, LOOKUP, 0); 529 if (ip == NULL) 530 return; 531 if ((ip->i_mode&IFMT) != IFLNK) { 532 u.u_error = ENXIO; 533 goto out; 534 } 535 u.u_error = rdwri(UIO_READ, ip, uap->buf, uap->count, 0, 0, &resid); 536 out: 537 iput(ip); 538 u.u_r.r_val1 = uap->count - resid; 539 } 540 541 /* 542 * Change mode of a file given path name. 543 */ 544 chmod() 545 { 546 struct inode *ip; 547 struct a { 548 char *fname; 549 int fmode; 550 } *uap; 551 552 uap = (struct a *)u.u_ap; 553 if ((ip = owner(1)) == NULL) 554 return; 555 chmod1(ip, uap->fmode); 556 iput(ip); 557 } 558 559 /* 560 * Change mode of a file given a file descriptor. 561 */ 562 fchmod() 563 { 564 struct a { 565 int fd; 566 int fmode; 567 } *uap; 568 register struct inode *ip; 569 register struct file *fp; 570 571 uap = (struct a *)u.u_ap; 572 fp = getf(uap->fd); 573 if (fp == NULL) 574 return; 575 if (fp->f_type == DTYPE_SOCKET) { 576 u.u_error = EINVAL; 577 return; 578 } 579 ip = fp->f_inode; 580 if (u.u_uid != ip->i_uid && !suser()) 581 return; 582 ilock(ip); 583 chmod1(ip, uap->fmode); 584 iunlock(ip); 585 } 586 587 /* 588 * Change the mode on a file. 589 * Inode must be locked before calling. 590 */ 591 chmod1(ip, mode) 592 register struct inode *ip; 593 register int mode; 594 { 595 register int *gp; 596 597 ip->i_mode &= ~07777; 598 if (u.u_uid) { 599 mode &= ~ISVTX; 600 if (u.u_gid == ip->i_gid) 601 goto ok; 602 for (gp = u.u_groups; gp < &u.u_groups[NGROUPS]; gp++) 603 if (*gp == ip->i_gid) 604 goto ok; 605 mode &= ~ISGID; 606 ok: 607 ; 608 #ifdef MUSH 609 if (u.u_quota->q_syflags & QF_UMASK && u.u_uid != 0 && 610 (ip->i_mode & IFMT) != IFCHR) 611 mode &= ~u.u_cmask; 612 #endif 613 } 614 ip->i_mode |= mode&07777; 615 ip->i_flag |= ICHG; 616 if (ip->i_flag&ITEXT && (ip->i_mode&ISVTX)==0) 617 xrele(ip); 618 } 619 620 /* 621 * Set ownership given a path name. 622 */ 623 chown() 624 { 625 struct inode *ip; 626 struct a { 627 char *fname; 628 int uid; 629 int gid; 630 } *uap; 631 632 uap = (struct a *)u.u_ap; 633 if (!suser() || (ip = owner(0)) == NULL) 634 return; 635 chown1(ip, uap->uid, uap->gid); 636 iput(ip); 637 } 638 639 /* 640 * Set ownership given a file descriptor. 641 */ 642 fchown() 643 { 644 struct a { 645 int fd; 646 int uid; 647 int gid; 648 } *uap; 649 register struct inode *ip; 650 register struct file *fp; 651 652 uap = (struct a *)u.u_ap; 653 fp = getf(uap->fd); 654 if (fp == NULL) 655 return; 656 if (fp->f_type == DTYPE_SOCKET) { 657 u.u_error = EINVAL; 658 return; 659 } 660 ip = fp->f_inode; 661 if (!suser()) 662 return; 663 ilock(ip); 664 chown1(ip, uap->uid, uap->gid); 665 iunlock(ip); 666 } 667 668 /* 669 * Perform chown operation on inode ip; 670 * inode must be locked prior to call. 671 */ 672 chown1(ip, uid, gid) 673 register struct inode *ip; 674 int uid, gid; 675 { 676 #ifdef QUOTA 677 register long change; 678 679 /* 680 * This doesn't allow for holes in files (which hopefully don't 681 * happen often in files that we chown), and is not accurate anyway 682 * (eg: it totally ignores 3 level indir blk files - but hopefully 683 * noone who can make a file that big will have a quota) 684 */ 685 if (ip->i_uid == uid) 686 change = 0; 687 else { 688 register struct fs *fs = ip->i_fs; 689 690 if (ip->i_size > (change = NDADDR * fs->fs_bsize)) { 691 register off_t size; 692 693 size = blkroundup(fs, ip->i_size) - change; 694 change += size; 695 change += fs->fs_bsize; 696 /* this assumes NIADDR <= 2 */ 697 if (size > NINDIR(fs) * fs->fs_bsize) 698 change += fs->fs_bsize; 699 } else 700 change = fragroundup(fs, ip->i_size); 701 change /= DEV_BSIZE; 702 } 703 (void)chkdq(ip, -change, 1); 704 (void)chkiq(ip->i_dev, ip, ip->i_uid, 1); 705 dqrele(ip->i_dquot); 706 #endif 707 /* 708 * keep uid/gid's in sane range -- no err, 709 * so chown(file, uid, -1) will do something useful 710 */ 711 if (uid >= 0 && uid <= 32767) /* should have a constant */ 712 ip->i_uid = uid; 713 if (gid >= 0 && gid <= 32767) /* same here */ 714 ip->i_gid = gid; 715 ip->i_flag |= ICHG; 716 if (u.u_ruid != 0) 717 ip->i_mode &= ~(ISUID|ISGID); 718 #ifdef QUOTA 719 ip->i_dquot = inoquota(ip); 720 (void)chkdq(ip, change, 1); 721 (void)chkiq(ip->i_dev, (struct inode *)NULL, uid, 1); 722 #endif 723 } 724 725 /* 726 * Set IUPD and IACC times on file. 727 * Can't set ICHG. 728 */ 729 outime() 730 { 731 register struct a { 732 char *fname; 733 time_t *tptr; 734 } *uap; 735 register struct inode *ip; 736 time_t tv[2]; 737 struct timeval tv0, tv1; 738 739 uap = (struct a *)u.u_ap; 740 if ((ip = owner(1)) == NULL) 741 return; 742 u.u_error = copyin((caddr_t)uap->tptr, (caddr_t)tv, sizeof(tv)); 743 if (u.u_error == 0) { 744 ip->i_flag |= IACC|IUPD|ICHG; 745 tv0.tv_sec = tv[0]; tv0.tv_usec = 0; 746 tv1.tv_sec = tv[1]; tv1.tv_usec = 0; 747 iupdat(ip, &tv0, &tv1, 0); 748 } 749 iput(ip); 750 } 751 752 /* 753 * Flush any pending I/O. 754 */ 755 sync() 756 { 757 758 update(); 759 } 760 761 /* 762 * Apply an advisory lock on a file descriptor. 763 */ 764 flock() 765 { 766 struct a { 767 int fd; 768 int how; 769 } *uap; 770 register struct file *fp; 771 register int cmd, flags; 772 773 uap = (struct a *)u.u_ap; 774 fp = getf(uap->fd); 775 if (fp == NULL) 776 return; 777 if (fp->f_type == DTYPE_SOCKET) { /* XXX */ 778 u.u_error = EINVAL; 779 return; 780 } 781 cmd = uap->how; 782 flags = u.u_pofile[uap->fd] & (UF_SHLOCK|UF_EXLOCK); 783 if (cmd&FUNLOCK) { 784 if (flags == 0) { 785 u.u_error = EINVAL; 786 return; 787 } 788 funlocki(fp->f_inode, flags); 789 u.u_pofile[uap->fd] &= ~(UF_SHLOCK|UF_EXLOCK); 790 return; 791 } 792 /* 793 * No reason to write lock a file we've already 794 * write locked, similarly with a read lock. 795 */ 796 if ((flags&UF_EXLOCK) && (cmd&FEXLOCK) || 797 (flags&UF_SHLOCK) && (cmd&FSHLOCK)) 798 return; 799 u.u_pofile[uap->fd] = flocki(fp->f_inode, u.u_pofile[uap->fd], cmd); 800 } 801 802 /* 803 * Truncate a file given its path name. 804 */ 805 truncate() 806 { 807 struct a { 808 char *fname; 809 u_long length; 810 } *uap = (struct a *)u.u_ap; 811 struct inode *ip; 812 813 ip = namei(uchar, LOOKUP, 1); 814 if (ip == NULL) 815 return; 816 if (access(ip, IWRITE)) 817 goto bad; 818 if ((ip->i_mode&IFMT) == IFDIR) { 819 u.u_error = EISDIR; 820 goto bad; 821 } 822 itrunc(ip, uap->length); 823 bad: 824 iput(ip); 825 } 826 827 /* 828 * Truncate a file given a file descriptor. 829 */ 830 ftruncate() 831 { 832 struct a { 833 int fd; 834 u_long length; 835 } *uap = (struct a *)u.u_ap; 836 struct inode *ip; 837 struct file *fp; 838 839 fp = getf(uap->fd); 840 if (fp == NULL) 841 return; 842 if (fp->f_type == DTYPE_SOCKET) { 843 u.u_error = EINVAL; 844 return; 845 } 846 if ((fp->f_flag&FWRITE) == 0) { 847 u.u_error = EINVAL; 848 return; 849 } 850 ip = fp->f_inode; 851 ilock(ip); 852 itrunc(ip, uap->length); 853 iunlock(ip); 854 } 855 856 /* 857 * Synch an open file. 858 */ 859 fsync() 860 { 861 struct a { 862 int fd; 863 } *uap = (struct a *)u.u_ap; 864 struct inode *ip; 865 struct file *fp; 866 867 fp = getf(uap->fd); 868 if (fp == NULL) 869 return; 870 if (fp->f_type == DTYPE_SOCKET) { 871 u.u_error = EINVAL; 872 return; 873 } 874 ip = fp->f_inode; 875 ilock(ip); 876 syncip(ip); 877 iunlock(ip); 878 } 879 880 /* 881 * Rename system call. 882 * rename("foo", "bar"); 883 * is essentially 884 * unlink("bar"); 885 * link("foo", "bar"); 886 * unlink("foo"); 887 * but ``atomically''. Can't do full commit without saving state in the 888 * inode on disk which isn't feasible at this time. Best we can do is 889 * always guarantee the target exists. 890 * 891 * Basic algorithm is: 892 * 893 * 1) Bump link count on source while we're linking it to the 894 * target. This also insure the inode won't be deleted out 895 * from underneath us while we work. 896 * 2) Link source to destination. If destination already exists, 897 * delete it first. 898 * 3) Unlink source reference to inode if still around. 899 * 4) If a directory was moved and the parent of the destination 900 * is different from the source, patch the ".." entry in the 901 * directory. 902 * 903 * Source and destination must either both be directories, or both 904 * not be directories. If target is a directory, it must be empty. 905 */ 906 rename() 907 { 908 struct a { 909 char *from; 910 char *to; 911 } *uap; 912 register struct inode *ip, *xp, *dp; 913 int oldparent, parentdifferent, doingdirectory; 914 int error = 0; 915 916 uap = (struct a *)u.u_ap; 917 ip = namei(uchar, LOOKUP | LOCKPARENT, 0); 918 if (ip == NULL) 919 return; 920 dp = u.u_pdir; 921 oldparent = 0, doingdirectory = 0; 922 if ((ip->i_mode&IFMT) == IFDIR) { 923 register struct direct *d; 924 925 d = &u.u_dent; 926 /* 927 * Avoid "." and ".." for obvious reasons. 928 */ 929 if (d->d_name[0] == '.') { 930 if (d->d_namlen == 1 || 931 (d->d_namlen == 2 && d->d_name[1] == '.')) { 932 iput(ip); 933 u.u_error = EINVAL; 934 return; 935 } 936 } 937 oldparent = dp->i_number; 938 doingdirectory++; 939 } 940 irele(dp); 941 942 /* 943 * 1) Bump link count while we're moving stuff 944 * around. If we crash somewhere before 945 * completing our work, the link count 946 * may be wrong, but correctable. 947 */ 948 ip->i_nlink++; 949 ip->i_flag |= ICHG; 950 iupdat(ip, &time, &time, 1); 951 iunlock(ip); 952 953 /* 954 * When the target exists, both the directory 955 * and target inodes are returned locked. 956 */ 957 u.u_dirp = (caddr_t)uap->to; 958 xp = namei(uchar, CREATE | LOCKPARENT, 0); 959 if (u.u_error) { 960 error = u.u_error; 961 goto out; 962 } 963 dp = u.u_pdir; 964 /* 965 * 2) If target doesn't exist, link the target 966 * to the source and unlink the source. 967 * Otherwise, rewrite the target directory 968 * entry to reference the source inode and 969 * expunge the original entry's existence. 970 */ 971 parentdifferent = oldparent != dp->i_number; 972 if (xp == NULL) { 973 if (dp->i_dev != ip->i_dev) { 974 error = EXDEV; 975 goto bad; 976 } 977 /* 978 * Disallow rename(foo, foo/bar). 979 */ 980 if (dp->i_number == ip->i_number) { 981 error = EEXIST; 982 goto bad; 983 } 984 /* 985 * Account for ".." in directory. 986 * When source and destination have the 987 * same parent we don't fool with the 988 * link count -- this isn't required 989 * because we do a similar check below. 990 */ 991 if (doingdirectory && parentdifferent) { 992 dp->i_nlink++; 993 dp->i_flag |= ICHG; 994 iupdat(dp, &time, &time, 1); 995 } 996 error = direnter(ip); 997 if (error) 998 goto out; 999 } else { 1000 if (xp->i_dev != dp->i_dev || xp->i_dev != ip->i_dev) { 1001 error = EXDEV; 1002 goto bad; 1003 } 1004 /* 1005 * Short circuit rename(foo, foo). 1006 */ 1007 if (xp->i_number == ip->i_number) 1008 goto bad; 1009 /* 1010 * Target must be empty if a directory 1011 * and have no links to it. 1012 * Also, insure source and target are 1013 * compatible (both directories, or both 1014 * not directories). 1015 */ 1016 if ((xp->i_mode&IFMT) == IFDIR) { 1017 if (!dirempty(xp) || xp->i_nlink > 2) { 1018 error = ENOTEMPTY; 1019 goto bad; 1020 } 1021 if (!doingdirectory) { 1022 error = ENOTDIR; 1023 goto bad; 1024 } 1025 } else if (doingdirectory) { 1026 error = EISDIR; 1027 goto bad; 1028 } 1029 dirrewrite(dp, ip); 1030 if (u.u_error) { 1031 error = u.u_error; 1032 goto bad1; 1033 } 1034 /* 1035 * Adjust the link count of the target to 1036 * reflect the dirrewrite above. If this is 1037 * a directory it is empty and there are 1038 * no links to it, so we can squash the inode and 1039 * any space associated with it. We disallowed 1040 * renaming over top of a directory with links to 1041 * it above, as we've no way to determine if 1042 * we've got a link or the directory itself, and 1043 * if we get a link, then ".." will be screwed up. 1044 */ 1045 xp->i_nlink--; 1046 if (doingdirectory) { 1047 if (--xp->i_nlink != 0) 1048 panic("rename: linked directory"); 1049 itrunc(xp, (u_long)0); 1050 } 1051 xp->i_flag |= ICHG; 1052 iput(xp); 1053 xp = NULL; 1054 } 1055 1056 /* 1057 * 3) Unlink the source. 1058 */ 1059 u.u_dirp = uap->from; 1060 dp = namei(uchar, DELETE, 0); 1061 /* 1062 * Insure directory entry still exists and 1063 * has not changed since the start of all 1064 * this. If either has occured, forget about 1065 * about deleting the original entry and just 1066 * adjust the link count in the inode. 1067 */ 1068 if (dp == NULL || u.u_dent.d_ino != ip->i_number) { 1069 ip->i_nlink--; 1070 ip->i_flag |= ICHG; 1071 } else { 1072 /* 1073 * If source is a directory, must adjust 1074 * link count of parent directory also. 1075 * If target didn't exist and source and 1076 * target have the same parent, then we 1077 * needn't touch the link count, it all 1078 * balances out in the end. Otherwise, we 1079 * must do so to reflect deletion of ".." 1080 * done above. 1081 */ 1082 if (doingdirectory && (xp != NULL || parentdifferent)) { 1083 dp->i_nlink--; 1084 dp->i_flag |= ICHG; 1085 } 1086 if (dirremove()) { 1087 ip->i_nlink--; 1088 ip->i_flag |= ICHG; 1089 } 1090 if (error == 0) /* conservative */ 1091 error = u.u_error; 1092 } 1093 irele(ip); 1094 if (dp) 1095 iput(dp); 1096 1097 /* 1098 * 4) Renaming a directory with the parent 1099 * different requires ".." to be rewritten. 1100 * The window is still there for ".." to 1101 * be inconsistent, but this is unavoidable, 1102 * and a lot shorter than when it was done 1103 * in a user process. 1104 */ 1105 if (doingdirectory && parentdifferent && error == 0) { 1106 struct dirtemplate dirbuf; 1107 1108 u.u_dirp = uap->to; 1109 ip = namei(uchar, LOOKUP | LOCKPARENT, 0); 1110 if (ip == NULL) { 1111 printf("rename: .. went away\n"); 1112 return; 1113 } 1114 dp = u.u_pdir; 1115 if ((ip->i_mode&IFMT) != IFDIR) { 1116 printf("rename: .. not a directory\n"); 1117 goto stuck; 1118 } 1119 error = rdwri(UIO_READ, ip, (caddr_t)&dirbuf, 1120 sizeof (struct dirtemplate), (off_t)0, 1, (int *)0); 1121 if (error == 0) { 1122 dirbuf.dotdot_ino = dp->i_number; 1123 (void) rdwri(UIO_WRITE, ip, (caddr_t)&dirbuf, 1124 sizeof (struct dirtemplate), (off_t)0, 1, (int *)0); 1125 } 1126 stuck: 1127 irele(dp); 1128 iput(ip); 1129 } 1130 goto done; 1131 1132 bad: 1133 iput(dp); 1134 bad1: 1135 if (xp) 1136 iput(xp); 1137 out: 1138 ip->i_nlink--; 1139 ip->i_flag |= ICHG; 1140 irele(ip); 1141 done: 1142 if (error) 1143 u.u_error = error; 1144 } 1145 1146 /* 1147 * Make a new file. 1148 */ 1149 struct inode * 1150 maknode(mode) 1151 int mode; 1152 { 1153 register struct inode *ip; 1154 ino_t ipref; 1155 1156 if ((mode & IFMT) == IFDIR) 1157 ipref = dirpref(u.u_pdir->i_fs); 1158 else 1159 ipref = u.u_pdir->i_number; 1160 ip = ialloc(u.u_pdir, ipref, mode); 1161 if (ip == NULL) { 1162 iput(u.u_pdir); 1163 return (NULL); 1164 } 1165 #ifdef QUOTA 1166 if (ip->i_dquot != NODQUOT) 1167 panic("maknode: dquot"); 1168 #endif 1169 ip->i_flag |= IACC|IUPD|ICHG; 1170 if ((mode & IFMT) == 0) 1171 mode |= IFREG; 1172 ip->i_mode = mode & ~u.u_cmask; 1173 ip->i_nlink = 1; 1174 ip->i_uid = u.u_uid; 1175 ip->i_gid = u.u_pdir->i_gid; 1176 #ifdef QUOTA 1177 ip->i_dquot = inoquota(ip); 1178 #endif 1179 1180 /* 1181 * Make sure inode goes to disk before directory entry. 1182 */ 1183 iupdat(ip, &time, &time, 1); 1184 u.u_error = direnter(ip); 1185 if (u.u_error) { 1186 /* 1187 * Write error occurred trying to update directory 1188 * so must deallocate the inode. 1189 */ 1190 ip->i_nlink = 0; 1191 ip->i_flag |= ICHG; 1192 iput(ip); 1193 return (NULL); 1194 } 1195 return (ip); 1196 } 1197