ext2fs_readwrite.c revision 1.79
1 /* $NetBSD: ext2fs_readwrite.c,v 1.79 2024/10/19 14:13:44 jakllsch Exp $ */ 2 3 /*- 4 * Copyright (c) 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * @(#)ufs_readwrite.c 8.8 (Berkeley) 8/4/94 32 * Modified for ext2fs by Manuel Bouyer. 33 */ 34 35 /*- 36 * Copyright (c) 1997 Manuel Bouyer. 37 * 38 * Redistribution and use in source and binary forms, with or without 39 * modification, are permitted provided that the following conditions 40 * are met: 41 * 1. Redistributions of source code must retain the above copyright 42 * notice, this list of conditions and the following disclaimer. 43 * 2. Redistributions in binary form must reproduce the above copyright 44 * notice, this list of conditions and the following disclaimer in the 45 * documentation and/or other materials provided with the distribution. 46 * 47 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 48 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 49 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 50 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 51 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 52 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 53 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 54 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 55 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 56 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 57 * 58 * @(#)ufs_readwrite.c 8.8 (Berkeley) 8/4/94 59 * Modified for ext2fs by Manuel Bouyer. 60 */ 61 62 #include <sys/cdefs.h> 63 __KERNEL_RCSID(0, "$NetBSD: ext2fs_readwrite.c,v 1.79 2024/10/19 14:13:44 jakllsch Exp $"); 64 65 #include <sys/param.h> 66 #include <sys/systm.h> 67 #include <sys/resourcevar.h> 68 #include <sys/kernel.h> 69 #include <sys/file.h> 70 #include <sys/stat.h> 71 #include <sys/buf.h> 72 #include <sys/proc.h> 73 #include <sys/mount.h> 74 #include <sys/vnode.h> 75 #include <sys/signalvar.h> 76 #include <sys/kauth.h> 77 #include <sys/bitops.h> 78 79 #include <ufs/ufs/inode.h> 80 #include <ufs/ufs/ufsmount.h> 81 #include <ufs/ufs/ufs_extern.h> 82 #include <ufs/ext2fs/ext2fs.h> 83 #include <ufs/ext2fs/ext2fs_extern.h> 84 85 static int ext2fs_post_read_update(struct vnode *, int, int); 86 static int ext2fs_post_write_update(struct vnode *, struct uio *, int, 87 kauth_cred_t, off_t, int, int); 88 89 /* 90 * Vnode op for reading. 91 */ 92 /* ARGSUSED */ 93 int 94 ext2fs_read(void *v) 95 { 96 struct vop_read_args /* { 97 struct vnode *a_vp; 98 struct uio *a_uio; 99 int a_ioflag; 100 kauth_cred_t a_cred; 101 } */ *ap = v; 102 struct vnode *vp; 103 struct inode *ip; 104 struct uio *uio; 105 struct ufsmount *ump; 106 vsize_t bytelen; 107 int advice; 108 int error; 109 110 vp = ap->a_vp; 111 ip = VTOI(vp); 112 ump = ip->i_ump; 113 uio = ap->a_uio; 114 error = 0; 115 116 KASSERT(uio->uio_rw == UIO_READ); 117 KASSERT(vp->v_type == VREG || vp->v_type == VDIR); 118 119 /* XXX Eliminate me by refusing directory reads from userland. */ 120 if (vp->v_type == VDIR) 121 return ext2fs_bufrd(vp, uio, ap->a_ioflag, ap->a_cred); 122 123 if ((uint64_t)uio->uio_offset > ump->um_maxfilesize) 124 return EFBIG; 125 if (uio->uio_resid == 0) 126 return 0; 127 if (uio->uio_offset >= ext2fs_size(ip)) 128 goto out; 129 130 KASSERT(vp->v_type == VREG); 131 advice = IO_ADV_DECODE(ap->a_ioflag); 132 while (uio->uio_resid > 0) { 133 bytelen = MIN(ext2fs_size(ip) - uio->uio_offset, 134 uio->uio_resid); 135 if (bytelen == 0) 136 break; 137 138 error = ubc_uiomove(&vp->v_uobj, uio, bytelen, advice, 139 UBC_READ | UBC_PARTIALOK | UBC_VNODE_FLAGS(vp)); 140 if (error) 141 break; 142 } 143 144 out: 145 error = ext2fs_post_read_update(vp, ap->a_ioflag, error); 146 return error; 147 } 148 149 /* 150 * UFS op for reading via the buffer cache 151 */ 152 int 153 ext2fs_bufrd(struct vnode *vp, struct uio *uio, int ioflag, kauth_cred_t cred) 154 { 155 struct inode *ip; 156 struct ufsmount *ump; 157 struct m_ext2fs *fs; 158 struct buf *bp; 159 off_t bytesinfile; 160 daddr_t lbn, nextlbn; 161 long size, xfersize, blkoffset; 162 int error; 163 164 KASSERT(uio->uio_rw == UIO_READ); 165 KASSERT(VOP_ISLOCKED(vp)); 166 KASSERT(vp->v_type == VDIR || vp->v_type == VLNK); 167 168 ip = VTOI(vp); 169 ump = ip->i_ump; 170 fs = ip->i_e2fs; 171 error = 0; 172 173 KASSERT(vp->v_type != VLNK || 174 ext2fs_size(ip) >= ump->um_maxsymlinklen); 175 KASSERT(vp->v_type != VLNK || ump->um_maxsymlinklen != 0 || 176 ext2fs_nblock(ip) != 0); 177 178 if (uio->uio_offset > ump->um_maxfilesize) 179 return EFBIG; 180 if (uio->uio_resid == 0) 181 return 0; 182 if (uio->uio_offset >= ext2fs_size(ip)) 183 goto out; 184 185 for (error = 0, bp = NULL; uio->uio_resid > 0; bp = NULL) { 186 bytesinfile = ext2fs_size(ip) - uio->uio_offset; 187 if (bytesinfile <= 0) 188 break; 189 lbn = ext2_lblkno(fs, uio->uio_offset); 190 nextlbn = lbn + 1; 191 size = fs->e2fs_bsize; 192 blkoffset = ext2_blkoff(fs, uio->uio_offset); 193 xfersize = fs->e2fs_bsize - blkoffset; 194 if (uio->uio_resid < xfersize) 195 xfersize = uio->uio_resid; 196 if (bytesinfile < xfersize) 197 xfersize = bytesinfile; 198 199 if (ext2_lblktosize(fs, nextlbn) >= ext2fs_size(ip)) 200 error = bread(vp, lbn, size, 0, &bp); 201 else { 202 int nextsize = fs->e2fs_bsize; 203 error = breadn(vp, lbn, 204 size, &nextlbn, &nextsize, 1, 0, &bp); 205 } 206 if (error) 207 break; 208 209 /* 210 * We should only get non-zero b_resid when an I/O error 211 * has occurred, which should cause us to break above. 212 * However, if the short read did not cause an error, 213 * then we want to ensure that we do not uiomove bad 214 * or uninitialized data. 215 */ 216 size -= bp->b_resid; 217 if (size < xfersize) { 218 if (size == 0) 219 break; 220 xfersize = size; 221 } 222 error = uiomove((char *)bp->b_data + blkoffset, xfersize, uio); 223 if (error) 224 break; 225 brelse(bp, 0); 226 } 227 if (bp != NULL) 228 brelse(bp, 0); 229 230 out: 231 error = ext2fs_post_read_update(vp, ioflag, error); 232 return error; 233 } 234 235 static int 236 ext2fs_post_read_update(struct vnode *vp, int ioflag, int oerror) 237 { 238 struct inode *ip = VTOI(vp); 239 int error = oerror; 240 241 if (!(vp->v_mount->mnt_flag & MNT_NOATIME)) { 242 ip->i_flag |= IN_ACCESS; 243 if ((ioflag & IO_SYNC) == IO_SYNC) 244 error = ext2fs_update(vp, NULL, NULL, UPDATE_WAIT); 245 } 246 247 /* Read error overrides any inode update error. */ 248 if (oerror) 249 error = oerror; 250 return error; 251 } 252 253 /* 254 * Vnode op for writing. 255 */ 256 int 257 ext2fs_write(void *v) 258 { 259 struct vop_write_args /* { 260 struct vnode *a_vp; 261 struct uio *a_uio; 262 int a_ioflag; 263 kauth_cred_t a_cred; 264 } */ *ap = v; 265 struct vnode *vp; 266 struct uio *uio; 267 struct inode *ip; 268 struct m_ext2fs *fs; 269 struct ufsmount *ump; 270 off_t osize; 271 int blkoffset, error, ioflag, resid; 272 vsize_t bytelen; 273 off_t oldoff = 0; /* XXX */ 274 bool async; 275 int advice; 276 const unsigned int fshift = ilog2(MAXPHYS); 277 278 ioflag = ap->a_ioflag; 279 advice = IO_ADV_DECODE(ioflag); 280 uio = ap->a_uio; 281 vp = ap->a_vp; 282 ip = VTOI(vp); 283 ump = ip->i_ump; 284 error = 0; 285 286 KASSERT(uio->uio_rw == UIO_WRITE); 287 KASSERT(vp->v_type == VREG); 288 289 if (ioflag & IO_APPEND) 290 uio->uio_offset = ext2fs_size(ip); 291 if ((ip->i_e2fs_flags & EXT2_APPEND) && 292 uio->uio_offset != ext2fs_size(ip)) 293 return EPERM; 294 295 fs = ip->i_e2fs; 296 if (uio->uio_offset < 0 || 297 (uint64_t)uio->uio_offset + uio->uio_resid > ump->um_maxfilesize) 298 return EFBIG; 299 if (uio->uio_resid == 0) 300 return 0; 301 302 async = vp->v_mount->mnt_flag & MNT_ASYNC; 303 resid = uio->uio_resid; 304 osize = ext2fs_size(ip); 305 306 KASSERT(vp->v_type == VREG); 307 while (uio->uio_resid > 0) { 308 oldoff = uio->uio_offset; 309 blkoffset = ext2_blkoff(fs, uio->uio_offset); 310 bytelen = MIN(fs->e2fs_bsize - blkoffset, uio->uio_resid); 311 312 if (vp->v_size < oldoff + bytelen) { 313 uvm_vnp_setwritesize(vp, oldoff + bytelen); 314 } 315 error = ufs_balloc_range(vp, uio->uio_offset, bytelen, 316 ap->a_cred, 0); 317 if (error) 318 break; 319 error = ubc_uiomove(&vp->v_uobj, uio, bytelen, advice, 320 UBC_WRITE | UBC_VNODE_FLAGS(vp)); 321 if (error) 322 break; 323 324 /* 325 * update UVM's notion of the size now that we've 326 * copied the data into the vnode's pages. 327 */ 328 329 if (vp->v_size < uio->uio_offset) { 330 uvm_vnp_setsize(vp, uio->uio_offset); 331 } 332 333 /* 334 * flush what we just wrote if necessary. 335 * XXXUBC simplistic async flushing. 336 */ 337 338 if (!async && oldoff >> fshift != uio->uio_offset >> fshift) { 339 rw_enter(vp->v_uobj.vmobjlock, RW_WRITER); 340 error = VOP_PUTPAGES(vp, (oldoff >> fshift) << fshift, 341 (uio->uio_offset >> fshift) << fshift, 342 PGO_CLEANIT | PGO_LAZY); 343 } 344 } 345 if (error == 0 && ioflag & IO_SYNC) { 346 rw_enter(vp->v_uobj.vmobjlock, RW_WRITER); 347 error = VOP_PUTPAGES(vp, trunc_page(oldoff), 348 round_page(ext2_blkroundup(fs, uio->uio_offset)), 349 PGO_CLEANIT | PGO_SYNCIO); 350 } 351 352 error = ext2fs_post_write_update(vp, uio, ioflag, ap->a_cred, osize, 353 resid, error); 354 return error; 355 } 356 357 /* 358 * UFS op for writing via the buffer cache 359 */ 360 int 361 ext2fs_bufwr(struct vnode *vp, struct uio *uio, int ioflag, kauth_cred_t cred) 362 { 363 struct inode *ip; 364 struct ufsmount *ump; 365 struct m_ext2fs *fs; 366 struct buf *bp; 367 int flags; 368 off_t osize; 369 daddr_t lbn; 370 int resid, blkoffset, xfersize; 371 int error; 372 373 KASSERT(VOP_ISLOCKED(vp) == LK_EXCLUSIVE); 374 KASSERT(vp->v_type == VDIR || vp->v_type == VLNK); 375 KASSERT(vp->v_type != VDIR || ISSET(ioflag, IO_SYNC)); 376 KASSERT(uio->uio_rw == UIO_WRITE); 377 378 ip = VTOI(vp); 379 ump = ip->i_ump; 380 fs = ip->i_e2fs; 381 error = 0; 382 383 if (uio->uio_offset < 0 || 384 uio->uio_resid > ump->um_maxfilesize || 385 uio->uio_offset > (ump->um_maxfilesize - uio->uio_resid)) 386 return EFBIG; 387 if (uio->uio_resid == 0) 388 return 0; 389 390 flags = ioflag & IO_SYNC ? B_SYNC : 0; 391 resid = uio->uio_resid; 392 osize = ext2fs_size(ip); 393 394 for (error = 0; uio->uio_resid > 0;) { 395 lbn = ext2_lblkno(fs, uio->uio_offset); 396 blkoffset = ext2_blkoff(fs, uio->uio_offset); 397 xfersize = MIN(fs->e2fs_bsize - blkoffset, uio->uio_resid); 398 if (xfersize < fs->e2fs_bsize) 399 flags |= B_CLRBUF; 400 else 401 flags &= ~B_CLRBUF; 402 error = ext2fs_balloc(ip, lbn, blkoffset + xfersize, cred, &bp, 403 flags); 404 if (error) 405 break; 406 if (ext2fs_size(ip) < uio->uio_offset + xfersize) { 407 error = ext2fs_setsize(ip, uio->uio_offset + xfersize); 408 if (error) 409 break; 410 } 411 error = uiomove((char *)bp->b_data + blkoffset, xfersize, uio); 412 413 /* 414 * update UVM's notion of the size now that we've 415 * copied the data into the vnode's pages. 416 */ 417 418 if (vp->v_size < uio->uio_offset) { 419 uvm_vnp_setsize(vp, uio->uio_offset); 420 } 421 422 if (ioflag & IO_SYNC) 423 (void)bwrite(bp); 424 else if (xfersize + blkoffset == fs->e2fs_bsize) 425 bawrite(bp); 426 else 427 bdwrite(bp); 428 if (error || xfersize == 0) 429 break; 430 } 431 432 error = ext2fs_post_write_update(vp, uio, ioflag, cred, osize, resid, 433 error); 434 return error; 435 } 436 437 static int 438 ext2fs_post_write_update(struct vnode *vp, struct uio *uio, int ioflag, 439 kauth_cred_t cred, off_t osize, int resid, int oerror) 440 { 441 struct inode *ip = VTOI(vp); 442 int error = oerror; 443 444 /* Trigger ctime and mtime updates, and atime if MNT_RELATIME. */ 445 ip->i_flag |= IN_CHANGE | IN_UPDATE; 446 if (vp->v_mount->mnt_flag & MNT_RELATIME) 447 ip->i_flag |= IN_ACCESS; 448 449 /* 450 * If we successfully wrote any data and we are not the superuser, 451 * we clear the setuid and setgid bits as a precaution against 452 * tampering. 453 */ 454 if (resid > uio->uio_resid && cred) { 455 if (ip->i_e2fs_mode & ISUID) { 456 if (kauth_authorize_vnode(cred, 457 KAUTH_VNODE_RETAIN_SUID, vp, NULL, EPERM) != 0) 458 ip->i_e2fs_mode &= ISUID; 459 } 460 461 if (ip->i_e2fs_mode & ISGID) { 462 if (kauth_authorize_vnode(cred, 463 KAUTH_VNODE_RETAIN_SGID, vp, NULL, EPERM) != 0) 464 ip->i_e2fs_mode &= ~ISGID; 465 } 466 } 467 468 /* 469 * Update the size on disk: truncate back to original size on 470 * error, or reflect the new size on success. 471 */ 472 if (error) { 473 (void) ext2fs_truncate(vp, osize, ioflag & IO_SYNC, cred); 474 uio->uio_offset -= resid - uio->uio_resid; 475 uio->uio_resid = resid; 476 } else if (resid > uio->uio_resid && (ioflag & IO_SYNC) == IO_SYNC) 477 error = ext2fs_update(vp, NULL, NULL, UPDATE_WAIT); 478 479 /* Make sure the vnode uvm size matches the inode file size. */ 480 KASSERT(vp->v_size == ext2fs_size(ip)); 481 482 /* Write error overrides any inode update error. */ 483 if (oerror) 484 error = oerror; 485 return error; 486 } 487
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