ext2fs_readwrite.c revision 1.20
1 /* $NetBSD: ext2fs_readwrite.c,v 1.20 2001/11/08 02:39:07 lukem Exp $ */ 2 3 /*- 4 * Copyright (c) 1997 Manuel Bouyer. 5 * Copyright (c) 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)ufs_readwrite.c 8.8 (Berkeley) 8/4/94 37 * Modified for ext2fs by Manuel Bouyer. 38 */ 39 40 #include <sys/cdefs.h> 41 __KERNEL_RCSID(0, "$NetBSD: ext2fs_readwrite.c,v 1.20 2001/11/08 02:39:07 lukem Exp $"); 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/resourcevar.h> 46 #include <sys/kernel.h> 47 #include <sys/file.h> 48 #include <sys/stat.h> 49 #include <sys/buf.h> 50 #include <sys/proc.h> 51 #include <sys/conf.h> 52 #include <sys/mount.h> 53 #include <sys/vnode.h> 54 #include <sys/malloc.h> 55 #include <sys/signalvar.h> 56 57 #include <ufs/ufs/inode.h> 58 #include <ufs/ext2fs/ext2fs.h> 59 #include <ufs/ext2fs/ext2fs_extern.h> 60 61 62 #define doclusterread 0 /* XXX underway */ 63 #define doclusterwrite 0 64 65 /* 66 * Vnode op for reading. 67 */ 68 /* ARGSUSED */ 69 int 70 ext2fs_read(v) 71 void *v; 72 { 73 struct vop_read_args /* { 74 struct vnode *a_vp; 75 struct uio *a_uio; 76 int a_ioflag; 77 struct ucred *a_cred; 78 } */ *ap = v; 79 struct vnode *vp; 80 struct inode *ip; 81 struct uio *uio; 82 struct m_ext2fs *fs; 83 struct buf *bp; 84 void *win; 85 vsize_t bytelen; 86 ufs_daddr_t lbn, nextlbn; 87 off_t bytesinfile; 88 long size, xfersize, blkoffset; 89 int error; 90 91 vp = ap->a_vp; 92 ip = VTOI(vp); 93 uio = ap->a_uio; 94 95 #ifdef DIAGNOSTIC 96 if (uio->uio_rw != UIO_READ) 97 panic("%s: mode", "ext2fs_read"); 98 99 if (vp->v_type == VLNK) { 100 if ((int)ip->i_e2fs_size < vp->v_mount->mnt_maxsymlinklen || 101 (vp->v_mount->mnt_maxsymlinklen == 0 && 102 ip->i_e2fs_nblock == 0)) 103 panic("%s: short symlink", "ext2fs_read"); 104 } else if (vp->v_type != VREG && vp->v_type != VDIR) 105 panic("%s: type %d", "ext2fs_read", vp->v_type); 106 #endif 107 fs = ip->i_e2fs; 108 if ((u_int64_t)uio->uio_offset > 109 ((u_int64_t)0x80000000 * fs->e2fs_bsize - 1)) 110 return (EFBIG); 111 if (uio->uio_resid == 0) 112 return (0); 113 if (uio->uio_offset >= ip->i_e2fs_size) 114 return (0); 115 116 if (vp->v_type == VREG) { 117 error = 0; 118 while (uio->uio_resid > 0) { 119 bytelen = MIN(ip->i_e2fs_size - uio->uio_offset, 120 uio->uio_resid); 121 122 if (bytelen == 0) { 123 break; 124 } 125 win = ubc_alloc(&vp->v_uobj, uio->uio_offset, 126 &bytelen, UBC_READ); 127 error = uiomove(win, bytelen, uio); 128 ubc_release(win, 0); 129 if (error) { 130 break; 131 } 132 } 133 goto out; 134 } 135 136 for (error = 0, bp = NULL; uio->uio_resid > 0; bp = NULL) { 137 if ((bytesinfile = ip->i_e2fs_size - uio->uio_offset) <= 0) 138 break; 139 lbn = lblkno(fs, uio->uio_offset); 140 nextlbn = lbn + 1; 141 size = fs->e2fs_bsize; 142 blkoffset = blkoff(fs, uio->uio_offset); 143 xfersize = fs->e2fs_bsize - blkoffset; 144 if (uio->uio_resid < xfersize) 145 xfersize = uio->uio_resid; 146 if (bytesinfile < xfersize) 147 xfersize = bytesinfile; 148 149 if (lblktosize(fs, nextlbn) >= ip->i_e2fs_size) 150 error = bread(vp, lbn, size, NOCRED, &bp); 151 else { 152 int nextsize = fs->e2fs_bsize; 153 error = breadn(vp, lbn, 154 size, &nextlbn, &nextsize, 1, NOCRED, &bp); 155 } 156 if (error) 157 break; 158 159 /* 160 * We should only get non-zero b_resid when an I/O error 161 * has occurred, which should cause us to break above. 162 * However, if the short read did not cause an error, 163 * then we want to ensure that we do not uiomove bad 164 * or uninitialized data. 165 */ 166 size -= bp->b_resid; 167 if (size < xfersize) { 168 if (size == 0) 169 break; 170 xfersize = size; 171 } 172 error = uiomove((char *)bp->b_data + blkoffset, xfersize, uio); 173 if (error) 174 break; 175 brelse(bp); 176 } 177 if (bp != NULL) 178 brelse(bp); 179 180 out: 181 if (!(vp->v_mount->mnt_flag & MNT_NOATIME)) { 182 ip->i_flag |= IN_ACCESS; 183 if ((ap->a_ioflag & IO_SYNC) == IO_SYNC) 184 error = VOP_UPDATE(vp, NULL, NULL, UPDATE_WAIT); 185 } 186 return (error); 187 } 188 189 /* 190 * Vnode op for writing. 191 */ 192 int 193 ext2fs_write(v) 194 void *v; 195 { 196 struct vop_write_args /* { 197 struct vnode *a_vp; 198 struct uio *a_uio; 199 int a_ioflag; 200 struct ucred *a_cred; 201 } */ *ap = v; 202 struct vnode *vp; 203 struct uio *uio; 204 struct inode *ip; 205 struct m_ext2fs *fs; 206 struct buf *bp; 207 struct proc *p; 208 ufs_daddr_t lbn; 209 off_t osize; 210 int blkoffset, error, flags, ioflag, resid, xfersize; 211 vsize_t bytelen; 212 void *win; 213 off_t oldoff; 214 215 ioflag = ap->a_ioflag; 216 uio = ap->a_uio; 217 vp = ap->a_vp; 218 ip = VTOI(vp); 219 error = 0; 220 221 #ifdef DIAGNOSTIC 222 if (uio->uio_rw != UIO_WRITE) 223 panic("%s: mode", "ext2fs_write"); 224 #endif 225 226 switch (vp->v_type) { 227 case VREG: 228 if (ioflag & IO_APPEND) 229 uio->uio_offset = ip->i_e2fs_size; 230 if ((ip->i_e2fs_flags & EXT2_APPEND) && 231 uio->uio_offset != ip->i_e2fs_size) 232 return (EPERM); 233 /* FALLTHROUGH */ 234 case VLNK: 235 break; 236 case VDIR: 237 if ((ioflag & IO_SYNC) == 0) 238 panic("%s: nonsync dir write", "ext2fs_write"); 239 break; 240 default: 241 panic("%s: type", "ext2fs_write"); 242 } 243 244 fs = ip->i_e2fs; 245 if (uio->uio_offset < 0 || 246 (u_int64_t)uio->uio_offset + uio->uio_resid > 247 ((u_int64_t)0x80000000 * fs->e2fs_bsize - 1)) 248 return (EFBIG); 249 /* 250 * Maybe this should be above the vnode op call, but so long as 251 * file servers have no limits, I don't think it matters. 252 */ 253 p = uio->uio_procp; 254 if (vp->v_type == VREG && p && 255 uio->uio_offset + uio->uio_resid > 256 p->p_rlimit[RLIMIT_FSIZE].rlim_cur) { 257 psignal(p, SIGXFSZ); 258 return (EFBIG); 259 } 260 261 resid = uio->uio_resid; 262 osize = ip->i_e2fs_size; 263 264 if (vp->v_type == VREG) { 265 while (uio->uio_resid > 0) { 266 oldoff = uio->uio_offset; 267 blkoffset = blkoff(fs, uio->uio_offset); 268 bytelen = MIN(fs->e2fs_bsize - blkoffset, 269 uio->uio_resid); 270 271 error = ext2fs_balloc_range(vp, uio->uio_offset, 272 bytelen, ap->a_cred, 0); 273 if (error) { 274 break; 275 } 276 win = ubc_alloc(&vp->v_uobj, uio->uio_offset, 277 &bytelen, UBC_WRITE); 278 error = uiomove(win, bytelen, uio); 279 ubc_release(win, 0); 280 if (error) { 281 break; 282 } 283 284 /* 285 * flush what we just wrote if necessary. 286 * XXXUBC simplistic async flushing. 287 */ 288 289 if (oldoff >> 16 != uio->uio_offset >> 16) { 290 simple_lock(&vp->v_uobj.vmobjlock); 291 error = vp->v_uobj.pgops->pgo_put( 292 &vp->v_uobj, (oldoff >> 16) << 16, 293 (uio->uio_offset >> 16) << 16, PGO_CLEANIT); 294 } 295 } 296 if (error == 0 && ioflag & IO_SYNC) { 297 simple_lock(&vp->v_uobj.vmobjlock); 298 error = vp->v_uobj.pgops->pgo_put(&vp->v_uobj, oldoff, 299 oldoff + bytelen, PGO_CLEANIT|PGO_SYNCIO); 300 } 301 302 goto out; 303 } 304 305 flags = ioflag & IO_SYNC ? B_SYNC : 0; 306 for (error = 0; uio->uio_resid > 0;) { 307 lbn = lblkno(fs, uio->uio_offset); 308 blkoffset = blkoff(fs, uio->uio_offset); 309 xfersize = MIN(fs->e2fs_bsize - blkoffset, uio->uio_resid); 310 if (xfersize < fs->e2fs_bsize) 311 flags |= B_CLRBUF; 312 else 313 flags &= ~B_CLRBUF; 314 error = ext2fs_balloc(ip, 315 lbn, blkoffset + xfersize, ap->a_cred, &bp, flags); 316 if (error) 317 break; 318 if (ip->i_e2fs_size < uio->uio_offset + xfersize) { 319 ip->i_e2fs_size = uio->uio_offset + xfersize; 320 } 321 error = uiomove((char *)bp->b_data + blkoffset, xfersize, uio); 322 if (ioflag & IO_SYNC) 323 (void)bwrite(bp); 324 else if (xfersize + blkoffset == fs->e2fs_bsize) 325 bawrite(bp); 326 else 327 bdwrite(bp); 328 if (error || xfersize == 0) 329 break; 330 } 331 /* 332 * If we successfully wrote any data, and we are not the superuser 333 * we clear the setuid and setgid bits as a precaution against 334 * tampering. 335 */ 336 out: 337 ip->i_flag |= IN_CHANGE | IN_UPDATE; 338 if (resid > uio->uio_resid && ap->a_cred && ap->a_cred->cr_uid != 0) 339 ip->i_e2fs_mode &= ~(ISUID | ISGID); 340 if (error) { 341 (void) VOP_TRUNCATE(vp, osize, ioflag & IO_SYNC, ap->a_cred, 342 uio->uio_procp); 343 uio->uio_offset -= resid - uio->uio_resid; 344 uio->uio_resid = resid; 345 } else if (resid > uio->uio_resid && (ioflag & IO_SYNC) == IO_SYNC) 346 error = VOP_UPDATE(vp, NULL, NULL, UPDATE_WAIT); 347 KASSERT(vp->v_size == ip->i_e2fs_size); 348 return (error); 349 } 350
Indexes created Tue Sep 30 20:09:53 GMT 2025