1 /* 2 * Copyright (c) 1993 Jan-Simon Pendry 3 * Copyright (c) 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Jan-Simon Pendry. 8 * 9 * %sccs.include.redist.c% 10 * 11 * @(#)procfs_vnops.c 8.5 (Berkeley) 01/27/94 12 * 13 * From: 14 * $Id: procfs_vnops.c,v 3.2 1993/12/15 09:40:17 jsp Exp $ 15 */ 16 17 /* 18 * procfs vnode interface 19 */ 20 21 #include <sys/param.h> 22 #include <sys/systm.h> 23 #include <sys/time.h> 24 #include <sys/kernel.h> 25 #include <sys/file.h> 26 #include <sys/proc.h> 27 #include <sys/vnode.h> 28 #include <sys/namei.h> 29 #include <sys/malloc.h> 30 #include <sys/dirent.h> 31 #include <sys/resourcevar.h> 32 #include <miscfs/procfs/procfs.h> 33 #include <vm/vm.h> /* for PAGE_SIZE */ 34 35 /* 36 * Vnode Operations. 37 * 38 */ 39 40 /* 41 * This is a list of the valid names in the 42 * process-specific sub-directories. It is 43 * used in procfs_lookup and procfs_readdir 44 */ 45 static struct pfsnames { 46 u_short d_namlen; 47 char d_name[PROCFS_NAMELEN]; 48 pfstype d_pfstype; 49 } procent[] = { 50 #define N(s) sizeof(s)-1, s 51 /* namlen, nam, type */ 52 { N("file"), Pfile }, 53 { N("mem"), Pmem }, 54 { N("regs"), Pregs }, 55 { N("fpregs"), Pfpregs }, 56 { N("ctl"), Pctl }, 57 { N("status"), Pstatus }, 58 { N("note"), Pnote }, 59 { N("notepg"), Pnotepg }, 60 #undef N 61 }; 62 #define Nprocent (sizeof(procent)/sizeof(procent[0])) 63 64 static pid_t atopid __P((const char *, u_int)); 65 66 /* 67 * set things up for doing i/o on 68 * the pfsnode (vp). (vp) is locked 69 * on entry, and should be left locked 70 * on exit. 71 * 72 * for procfs we don't need to do anything 73 * in particular for i/o. all that is done 74 * is to support exclusive open on process 75 * memory images. 76 */ 77 procfs_open(ap) 78 struct vop_open_args *ap; 79 { 80 struct pfsnode *pfs = VTOPFS(ap->a_vp); 81 82 switch (pfs->pfs_type) { 83 case Pmem: 84 if (PFIND(pfs->pfs_pid) == 0) 85 return (ENOENT); /* was ESRCH, jsp */ 86 87 if ((pfs->pfs_flags & FWRITE) && (ap->a_mode & O_EXCL) || 88 (pfs->pfs_flags & O_EXCL) && (ap->a_mode & FWRITE)) 89 return (EBUSY); 90 91 92 if (ap->a_mode & FWRITE) 93 pfs->pfs_flags = ap->a_mode & (FWRITE|O_EXCL); 94 95 return (0); 96 97 default: 98 break; 99 } 100 101 return (0); 102 } 103 104 /* 105 * close the pfsnode (vp) after doing i/o. 106 * (vp) is not locked on entry or exit. 107 * 108 * nothing to do for procfs other than undo 109 * any exclusive open flag (see _open above). 110 */ 111 procfs_close(ap) 112 struct vop_close_args *ap; 113 { 114 struct pfsnode *pfs = VTOPFS(ap->a_vp); 115 116 switch (pfs->pfs_type) { 117 case Pmem: 118 if ((ap->a_fflag & FWRITE) && (pfs->pfs_flags & O_EXCL)) 119 pfs->pfs_flags &= ~(FWRITE|O_EXCL); 120 break; 121 } 122 123 return (0); 124 } 125 126 /* 127 * do an ioctl operation on pfsnode (vp). 128 * (vp) is not locked on entry or exit. 129 */ 130 procfs_ioctl(ap) 131 struct vop_ioctl_args *ap; 132 { 133 134 return (ENOTTY); 135 } 136 137 /* 138 * do block mapping for pfsnode (vp). 139 * since we don't use the buffer cache 140 * for procfs this function should never 141 * be called. in any case, it's not clear 142 * what part of the kernel ever makes use 143 * of this function. for sanity, this is the 144 * usual no-op bmap, although returning 145 * (EIO) would be a reasonable alternative. 146 */ 147 procfs_bmap(ap) 148 struct vop_bmap_args *ap; 149 { 150 151 if (ap->a_vpp != NULL) 152 *ap->a_vpp = ap->a_vp; 153 if (ap->a_bnp != NULL) 154 *ap->a_bnp = ap->a_bn; 155 return (0); 156 } 157 158 /* 159 * _inactive is called when the pfsnode 160 * is vrele'd and the reference count goes 161 * to zero. (vp) will be on the vnode free 162 * list, so to get it back vget() must be 163 * used. 164 * 165 * for procfs, check if the process is still 166 * alive and if it isn't then just throw away 167 * the vnode by calling vgone(). this may 168 * be overkill and a waste of time since the 169 * chances are that the process will still be 170 * there and PFIND is not free. 171 * 172 * (vp) is not locked on entry or exit. 173 */ 174 procfs_inactive(ap) 175 struct vop_inactive_args *ap; 176 { 177 struct pfsnode *pfs = VTOPFS(ap->a_vp); 178 179 if (PFIND(pfs->pfs_pid) == 0) 180 vgone(ap->a_vp); 181 182 return (0); 183 } 184 185 /* 186 * _reclaim is called when getnewvnode() 187 * wants to make use of an entry on the vnode 188 * free list. at this time the filesystem needs 189 * to free any private data and remove the node 190 * from any private lists. 191 */ 192 procfs_reclaim(ap) 193 struct vop_reclaim_args *ap; 194 { 195 int error; 196 197 error = procfs_freevp(ap->a_vp); 198 return (error); 199 } 200 201 /* 202 * Return POSIX pathconf information applicable to special devices. 203 */ 204 procfs_pathconf(ap) 205 struct vop_pathconf_args /* { 206 struct vnode *a_vp; 207 int a_name; 208 int *a_retval; 209 } */ *ap; 210 { 211 212 switch (ap->a_name) { 213 case _PC_LINK_MAX: 214 *ap->a_retval = LINK_MAX; 215 return (0); 216 case _PC_MAX_CANON: 217 *ap->a_retval = MAX_CANON; 218 return (0); 219 case _PC_MAX_INPUT: 220 *ap->a_retval = MAX_INPUT; 221 return (0); 222 case _PC_PIPE_BUF: 223 *ap->a_retval = PIPE_BUF; 224 return (0); 225 case _PC_CHOWN_RESTRICTED: 226 *ap->a_retval = 1; 227 return (0); 228 case _PC_VDISABLE: 229 *ap->a_retval = _POSIX_VDISABLE; 230 return (0); 231 default: 232 return (EINVAL); 233 } 234 /* NOTREACHED */ 235 } 236 237 /* 238 * _print is used for debugging. 239 * just print a readable description 240 * of (vp). 241 */ 242 procfs_print(ap) 243 struct vop_print_args *ap; 244 { 245 struct pfsnode *pfs = VTOPFS(ap->a_vp); 246 247 printf("tag VT_PROCFS, pid %d, mode %x, flags %x\n", 248 pfs->pfs_pid, 249 pfs->pfs_mode, pfs->pfs_flags); 250 } 251 252 /* 253 * _abortop is called when operations such as 254 * rename and create fail. this entry is responsible 255 * for undoing any side-effects caused by the lookup. 256 * this will always include freeing the pathname buffer. 257 */ 258 procfs_abortop(ap) 259 struct vop_abortop_args *ap; 260 { 261 262 if ((ap->a_cnp->cn_flags & (HASBUF | SAVESTART)) == HASBUF) 263 FREE(ap->a_cnp->cn_pnbuf, M_NAMEI); 264 return (0); 265 } 266 267 /* 268 * generic entry point for unsupported operations 269 */ 270 procfs_badop() 271 { 272 273 return (EIO); 274 } 275 276 /* 277 * Invent attributes for pfsnode (vp) and store 278 * them in (vap). 279 * Directories lengths are returned as zero since 280 * any real length would require the genuine size 281 * to be computed, and nothing cares anyway. 282 * 283 * this is relatively minimal for procfs. 284 */ 285 procfs_getattr(ap) 286 struct vop_getattr_args *ap; 287 { 288 struct pfsnode *pfs = VTOPFS(ap->a_vp); 289 struct vattr *vap = ap->a_vap; 290 struct proc *procp; 291 int error; 292 293 /* first check the process still exists */ 294 procp = PFIND(pfs->pfs_pid); 295 if (procp == 0) 296 return (ENOENT); 297 298 error = 0; 299 300 /* start by zeroing out the attributes */ 301 VATTR_NULL(vap); 302 303 /* next do all the common fields */ 304 vap->va_type = ap->a_vp->v_type; 305 vap->va_mode = pfs->pfs_mode; 306 vap->va_fileid = pfs->pfs_fileno; 307 vap->va_flags = 0; 308 vap->va_blocksize = PAGE_SIZE; 309 vap->va_bytes = vap->va_size = 0; 310 311 /* 312 * Make all times be current TOD. 313 * It would be possible to get the process start 314 * time from the p_stat structure, but there's 315 * no "file creation" time stamp anyway, and the 316 * p_stat structure is not addressible if u. gets 317 * swapped out for that process. 318 */ 319 microtime(&vap->va_ctime); 320 vap->va_atime = vap->va_mtime = vap->va_ctime; 321 322 /* 323 * now do the object specific fields 324 * 325 * The size could be set from struct reg, but it's hardly 326 * worth the trouble, and it puts some (potentially) machine 327 * dependent data into this machine-independent code. If it 328 * becomes important then this function should break out into 329 * a per-file stat function in the corresponding .c file. 330 */ 331 332 switch (pfs->pfs_type) { 333 case Proot: 334 vap->va_nlink = 2; 335 vap->va_uid = 0; 336 vap->va_gid = 0; 337 break; 338 339 case Pproc: 340 vap->va_nlink = 2; 341 vap->va_uid = procp->p_ucred->cr_uid; 342 vap->va_gid = procp->p_ucred->cr_gid; 343 break; 344 345 case Pfile: 346 error = EOPNOTSUPP; 347 break; 348 349 case Pmem: 350 vap->va_nlink = 1; 351 vap->va_bytes = vap->va_size = 352 ctob(procp->p_vmspace->vm_tsize + 353 procp->p_vmspace->vm_dsize + 354 procp->p_vmspace->vm_ssize); 355 vap->va_uid = procp->p_ucred->cr_uid; 356 vap->va_gid = procp->p_ucred->cr_gid; 357 break; 358 359 case Pregs: 360 case Pfpregs: 361 case Pctl: 362 case Pstatus: 363 case Pnote: 364 case Pnotepg: 365 vap->va_nlink = 1; 366 vap->va_uid = procp->p_ucred->cr_uid; 367 vap->va_gid = procp->p_ucred->cr_gid; 368 break; 369 370 default: 371 panic("procfs_getattr"); 372 } 373 374 return (error); 375 } 376 377 procfs_setattr(ap) 378 struct vop_setattr_args *ap; 379 { 380 /* 381 * just fake out attribute setting 382 * it's not good to generate an error 383 * return, otherwise things like creat() 384 * will fail when they try to set the 385 * file length to 0. worse, this means 386 * that echo $note > /proc/$pid/note will fail. 387 */ 388 389 return (0); 390 } 391 392 /* 393 * implement access checking. 394 * 395 * something very similar to this code is duplicated 396 * throughout the 4bsd kernel and should be moved 397 * into kern/vfs_subr.c sometime. 398 * 399 * actually, the check for super-user is slightly 400 * broken since it will allow read access to write-only 401 * objects. this doesn't cause any particular trouble 402 * but does mean that the i/o entry points need to check 403 * that the operation really does make sense. 404 */ 405 procfs_access(ap) 406 struct vop_access_args *ap; 407 { 408 struct vattr *vap; 409 struct vattr vattr; 410 int error; 411 412 /* 413 * If you're the super-user, 414 * you always get access. 415 */ 416 if (ap->a_cred->cr_uid == (uid_t) 0) 417 return (0); 418 vap = &vattr; 419 if (error = VOP_GETATTR(ap->a_vp, vap, ap->a_cred, ap->a_p)) 420 return (error); 421 422 /* 423 * Access check is based on only one of owner, group, public. 424 * If not owner, then check group. If not a member of the 425 * group, then check public access. 426 */ 427 if (ap->a_cred->cr_uid != vap->va_uid) { 428 gid_t *gp; 429 int i; 430 431 (ap->a_mode) >>= 3; 432 gp = ap->a_cred->cr_groups; 433 for (i = 0; i < ap->a_cred->cr_ngroups; i++, gp++) 434 if (vap->va_gid == *gp) 435 goto found; 436 ap->a_mode >>= 3; 437 found: 438 ; 439 } 440 441 if ((vap->va_mode & ap->a_mode) == ap->a_mode) 442 return (0); 443 444 return (EACCES); 445 } 446 447 /* 448 * lookup. this is incredibly complicated in the 449 * general case, however for most pseudo-filesystems 450 * very little needs to be done. 451 * 452 * unless you want to get a migraine, just make sure your 453 * filesystem doesn't do any locking of its own. otherwise 454 * read and inwardly digest ufs_lookup(). 455 */ 456 procfs_lookup(ap) 457 struct vop_lookup_args *ap; 458 { 459 struct componentname *cnp = ap->a_cnp; 460 struct vnode **vpp = ap->a_vpp; 461 struct vnode *dvp = ap->a_dvp; 462 char *pname = cnp->cn_nameptr; 463 int error = 0; 464 pid_t pid; 465 struct vnode *nvp; 466 struct pfsnode *pfs; 467 struct proc *procp; 468 pfstype pfs_type; 469 int i; 470 471 if (cnp->cn_namelen == 1 && *pname == '.') { 472 *vpp = dvp; 473 VREF(dvp); 474 /*VOP_LOCK(dvp);*/ 475 return (0); 476 } 477 478 *vpp = NULL; 479 480 pfs = VTOPFS(dvp); 481 switch (pfs->pfs_type) { 482 case Proot: 483 if (cnp->cn_flags & ISDOTDOT) 484 return (EIO); 485 486 if (CNEQ(cnp, "curproc", 7)) 487 pid = cnp->cn_proc->p_pid; 488 else 489 pid = atopid(pname, cnp->cn_namelen); 490 if (pid == NO_PID) 491 return (ENOENT); 492 493 procp = PFIND(pid); 494 if (procp == 0) 495 return (ENOENT); 496 497 error = procfs_allocvp(dvp->v_mount, &nvp, pid, Pproc); 498 if (error) 499 return (error); 500 501 nvp->v_type = VDIR; 502 pfs = VTOPFS(nvp); 503 504 *vpp = nvp; 505 return (0); 506 507 case Pproc: 508 if (cnp->cn_flags & ISDOTDOT) { 509 error = procfs_root(dvp->v_mount, vpp); 510 return (error); 511 } 512 513 procp = PFIND(pfs->pfs_pid); 514 if (procp == 0) 515 return (ENOENT); 516 517 for (i = 0; i < Nprocent; i++) { 518 struct pfsnames *dp = &procent[i]; 519 520 if (cnp->cn_namelen == dp->d_namlen && 521 bcmp(pname, dp->d_name, dp->d_namlen) == 0) { 522 pfs_type = dp->d_pfstype; 523 goto found; 524 } 525 } 526 return (ENOENT); 527 528 found: 529 if (pfs_type == Pfile) { 530 nvp = procfs_findtextvp(procp); 531 if (nvp) { 532 VREF(nvp); 533 VOP_LOCK(nvp); 534 } else { 535 error = ENXIO; 536 } 537 } else { 538 error = procfs_allocvp(dvp->v_mount, &nvp, 539 pfs->pfs_pid, pfs_type); 540 if (error) 541 return (error); 542 543 nvp->v_type = VREG; 544 pfs = VTOPFS(nvp); 545 } 546 *vpp = nvp; 547 return (error); 548 549 default: 550 return (ENOTDIR); 551 } 552 } 553 554 /* 555 * readdir returns directory entries from pfsnode (vp). 556 * 557 * the strategy here with procfs is to generate a single 558 * directory entry at a time (struct pfsdent) and then 559 * copy that out to userland using uiomove. a more efficent 560 * though more complex implementation, would try to minimize 561 * the number of calls to uiomove(). for procfs, this is 562 * hardly worth the added code complexity. 563 * 564 * this should just be done through read() 565 */ 566 procfs_readdir(ap) 567 struct vop_readdir_args *ap; 568 { 569 struct uio *uio = ap->a_uio; 570 struct pfsdent d; 571 struct pfsdent *dp = &d; 572 struct pfsnode *pfs; 573 int error; 574 int count; 575 int i; 576 577 pfs = VTOPFS(ap->a_vp); 578 579 if (uio->uio_resid < UIO_MX) 580 return (EINVAL); 581 if (uio->uio_offset & (UIO_MX-1)) 582 return (EINVAL); 583 if (uio->uio_offset < 0) 584 return (EINVAL); 585 586 error = 0; 587 count = 0; 588 i = uio->uio_offset / UIO_MX; 589 590 switch (pfs->pfs_type) { 591 /* 592 * this is for the process-specific sub-directories. 593 * all that is needed to is copy out all the entries 594 * from the procent[] table (top of this file). 595 */ 596 case Pproc: { 597 while (uio->uio_resid >= UIO_MX) { 598 struct pfsnames *dt; 599 600 if (i >= Nprocent) 601 break; 602 603 dt = &procent[i]; 604 605 dp->d_reclen = UIO_MX; 606 dp->d_fileno = PROCFS_FILENO(pfs->pfs_pid, dt->d_pfstype); 607 dp->d_type = DT_REG; 608 dp->d_namlen = dt->d_namlen; 609 bcopy(dt->d_name, dp->d_name, sizeof(dt->d_name)-1); 610 error = uiomove((caddr_t) dp, UIO_MX, uio); 611 if (error) 612 break; 613 count += UIO_MX; 614 i++; 615 } 616 617 break; 618 619 } 620 621 /* 622 * this is for the root of the procfs filesystem 623 * what is needed is a special entry for "curproc" 624 * followed by an entry for each process on allproc 625 #ifdef PROCFS_ZOMBIE 626 * and zombproc. 627 #endif 628 */ 629 630 case Proot: { 631 int pcnt; 632 #ifdef PROCFS_ZOMBIE 633 int doingzomb = 0; 634 #endif 635 volatile struct proc *p; 636 637 p = allproc; 638 639 #define PROCFS_XFILES 1 /* number of other entries, like "curproc" */ 640 pcnt = PROCFS_XFILES; 641 642 while (p && uio->uio_resid >= UIO_MX) { 643 bzero((char *) dp, UIO_MX); 644 dp->d_type = DT_DIR; 645 dp->d_reclen = UIO_MX; 646 647 switch (i) { 648 case 0: 649 /* ship out entry for "curproc" */ 650 dp->d_fileno = PROCFS_FILENO(PID_MAX+1, Pproc); 651 dp->d_namlen = sprintf(dp->d_name, "curproc"); 652 break; 653 654 default: 655 if (pcnt >= i) { 656 dp->d_fileno = PROCFS_FILENO(p->p_pid, Pproc); 657 dp->d_namlen = sprintf(dp->d_name, "%ld", (long) p->p_pid); 658 } 659 660 p = p->p_next; 661 662 #ifdef PROCFS_ZOMBIE 663 if (p == 0 && doingzomb == 0) { 664 doingzomb = 1; 665 p = zombproc; 666 } 667 #endif 668 669 if (pcnt++ < i) 670 continue; 671 672 break; 673 } 674 error = uiomove((caddr_t) dp, UIO_MX, uio); 675 if (error) 676 break; 677 count += UIO_MX; 678 i++; 679 } 680 681 break; 682 683 } 684 685 default: 686 error = ENOTDIR; 687 break; 688 } 689 690 uio->uio_offset = i * UIO_MX; 691 692 return (error); 693 } 694 695 /* 696 * convert decimal ascii to pid_t 697 */ 698 static pid_t 699 atopid(b, len) 700 const char *b; 701 u_int len; 702 { 703 pid_t p = 0; 704 705 while (len--) { 706 char c = *b++; 707 if (c < '0' || c > '9') 708 return (NO_PID); 709 p = 10 * p + (c - '0'); 710 if (p > PID_MAX) 711 return (NO_PID); 712 } 713 714 return (p); 715 } 716 717 /* 718 * procfs vnode operations. 719 */ 720 int (**procfs_vnodeop_p)(); 721 struct vnodeopv_entry_desc procfs_vnodeop_entries[] = { 722 { &vop_default_desc, vn_default_error }, 723 { &vop_lookup_desc, procfs_lookup }, /* lookup */ 724 { &vop_create_desc, procfs_create }, /* create */ 725 { &vop_mknod_desc, procfs_mknod }, /* mknod */ 726 { &vop_open_desc, procfs_open }, /* open */ 727 { &vop_close_desc, procfs_close }, /* close */ 728 { &vop_access_desc, procfs_access }, /* access */ 729 { &vop_getattr_desc, procfs_getattr }, /* getattr */ 730 { &vop_setattr_desc, procfs_setattr }, /* setattr */ 731 { &vop_read_desc, procfs_read }, /* read */ 732 { &vop_write_desc, procfs_write }, /* write */ 733 { &vop_ioctl_desc, procfs_ioctl }, /* ioctl */ 734 { &vop_select_desc, procfs_select }, /* select */ 735 { &vop_mmap_desc, procfs_mmap }, /* mmap */ 736 { &vop_fsync_desc, procfs_fsync }, /* fsync */ 737 { &vop_seek_desc, procfs_seek }, /* seek */ 738 { &vop_remove_desc, procfs_remove }, /* remove */ 739 { &vop_link_desc, procfs_link }, /* link */ 740 { &vop_rename_desc, procfs_rename }, /* rename */ 741 { &vop_mkdir_desc, procfs_mkdir }, /* mkdir */ 742 { &vop_rmdir_desc, procfs_rmdir }, /* rmdir */ 743 { &vop_symlink_desc, procfs_symlink }, /* symlink */ 744 { &vop_readdir_desc, procfs_readdir }, /* readdir */ 745 { &vop_readlink_desc, procfs_readlink }, /* readlink */ 746 { &vop_abortop_desc, procfs_abortop }, /* abortop */ 747 { &vop_inactive_desc, procfs_inactive }, /* inactive */ 748 { &vop_reclaim_desc, procfs_reclaim }, /* reclaim */ 749 { &vop_lock_desc, procfs_lock }, /* lock */ 750 { &vop_unlock_desc, procfs_unlock }, /* unlock */ 751 { &vop_bmap_desc, procfs_bmap }, /* bmap */ 752 { &vop_strategy_desc, procfs_strategy }, /* strategy */ 753 { &vop_print_desc, procfs_print }, /* print */ 754 { &vop_islocked_desc, procfs_islocked }, /* islocked */ 755 { &vop_pathconf_desc, procfs_pathconf }, /* pathconf */ 756 { &vop_advlock_desc, procfs_advlock }, /* advlock */ 757 { &vop_blkatoff_desc, procfs_blkatoff }, /* blkatoff */ 758 { &vop_valloc_desc, procfs_valloc }, /* valloc */ 759 { &vop_vfree_desc, procfs_vfree }, /* vfree */ 760 { &vop_truncate_desc, procfs_truncate }, /* truncate */ 761 { &vop_update_desc, procfs_update }, /* update */ 762 { (struct vnodeop_desc*)NULL, (int(*)())NULL } 763 }; 764 struct vnodeopv_desc procfs_vnodeop_opv_desc = 765 { &procfs_vnodeop_p, procfs_vnodeop_entries }; 766