kernel/syscall/getdents.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved.
  24  */
  25
  26 /*      Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T     */
  27 /*        All Rights Reserved   */
  28
  29 /*
  30  * Portions of this source code were derived from Berkeley 4.3 BSD
  31  * under license from the Regents of the University of California.
  32  */
  33
  34 #include <sys/param.h>
  35 #include <sys/isa_defs.h>
  36 #include <sys/types.h>
  37 #include <sys/inttypes.h>
  38 #include <sys/sysmacros.h>
  39 #include <sys/cred.h>
  40 #include <sys/dirent.h>
  41 #include <sys/systm.h>
  42 #include <sys/errno.h>
  43 #include <sys/vnode.h>
  44 #include <sys/file.h>
  45 #include <sys/mode.h>
  46 #include <sys/uio.h>
  47 #include <sys/filio.h>
  48 #include <sys/debug.h>
  49 #include <sys/kmem.h>
  50 #include <sys/cmn_err.h>
  51
  52 #if defined(_SYSCALL32_IMPL) || defined(_ILP32)
  53
  54 /*
  55  * Get directory entries in a file system-independent format.
  56  *
  57  * The 32-bit version of this function now allocates a buffer to grab the
  58  * directory entries in dirent64 formats from fop_readdir routines.
  59  * The dirent64 structures are converted to dirent32 structures and
  60  * copied to the user space.
  61  *
  62  * Both 32-bit and 64-bit versions of libc use getdents64() and therefore
  63  * we don't expect any major performance impact due to the extra kmem_alloc's
  64  * and copying done in this routine.
  65  */
  66
  67 /*
  68  * Native 32-bit system call for non-large-file applications.
  69  */
  70 int
  71 getdents32(int fd, void *buf, size_t count)
  72 {
  73         vnode_t *vp;
  74         file_t *fp;
  75         struct uio auio;
  76         struct iovec aiov;
  77         register int error;
  78         int sink;
  79         char *newbuf;
  80         char *obuf;
  81         int bufsize;
  82         int osize, nsize;
  83         struct dirent64 *dp;
  84         struct dirent32 *op;
  85
  86         if (count < sizeof (struct dirent32))
  87                 return (set_errno(EINVAL));
  88
  89         if ((fp = getf(fd)) == NULL)
  90                 return (set_errno(EBADF));
  91         vp = fp->f_vnode;
  92         if (vp->v_type != VDIR) {
  93                 releasef(fd);
  94                 return (set_errno(ENOTDIR));
  95         }
  96         if (!(fp->f_flag & FREAD)) {
  97                 releasef(fd);
  98                 return (set_errno(EBADF));
  99         }
 100
 101         /*
 102          * Don't let the user overcommit kernel resources.
 103          */
 104         if (count > MAXGETDENTS_SIZE)
 105                 count = MAXGETDENTS_SIZE;
 106
 107         bufsize = count;
 108         newbuf = kmem_alloc(bufsize, KM_SLEEP);
 109         obuf = kmem_alloc(bufsize, KM_SLEEP);
 110
 111         aiov.iov_base = newbuf;
 112         aiov.iov_len = count;
 113         auio.uio_iov = &aiov;
 114         auio.uio_iovcnt = 1;
 115         auio.uio_loffset = fp->f_offset;
 116         auio.uio_segflg = UIO_SYSSPACE;
 117         auio.uio_resid = count;
 118         auio.uio_fmode = 0;
 119         auio.uio_extflg = UIO_COPY_CACHED;
 120         (void) fop_rwlock(vp, V_WRITELOCK_FALSE, NULL);
 121         error = fop_readdir(vp, &auio, fp->f_cred, &sink, NULL, 0);
 122         fop_rwunlock(vp, V_WRITELOCK_FALSE, NULL);
 123         if (error)
 124                 goto out;
 125         count = count - auio.uio_resid;
 126         fp->f_offset = auio.uio_loffset;
 127
 128         dp = (struct dirent64 *)newbuf;
 129         op = (struct dirent32 *)obuf;
 130         osize = 0;
 131         nsize = 0;
 132
 133         while (nsize < count) {
 134                 uint32_t reclen, namlen;
 135
 136                 /*
 137                  * This check ensures that the 64 bit d_ino and d_off
 138                  * fields will fit into their 32 bit equivalents.
 139                  *
 140                  * Although d_off is a signed value, the check is done
 141                  * against the full 32 bits because certain file systems,
 142                  * NFS for one, allow directory cookies to use the full
 143                  * 32 bits.  We use uint64_t because there is no exact
 144                  * unsigned analog to the off64_t type of dp->d_off.
 145                  */
 146                 if (dp->d_ino > (ino64_t)UINT32_MAX ||
 147                     dp->d_off > (uint64_t)UINT32_MAX) {
 148                         error = EOVERFLOW;
 149                         goto out;
 150                 }
 151                 op->d_ino = (ino32_t)dp->d_ino;
 152                 op->d_off = (off32_t)dp->d_off;
 153                 namlen = strlen(dp->d_name);
 154                 reclen = DIRENT32_RECLEN(namlen);
 155                 op->d_reclen = (uint16_t)reclen;
 156
 157                 /* use strncpy(9f) to zero out uninitialized bytes */
 158
 159                 (void) strncpy(op->d_name, dp->d_name,
 160                     DIRENT32_NAMELEN(reclen));
 161                 nsize += (uint_t)dp->d_reclen;
 162                 osize += (uint_t)op->d_reclen;
 163                 dp = (struct dirent64 *)((char *)dp + (uint_t)dp->d_reclen);
 164                 op = (struct dirent32 *)((char *)op + (uint_t)op->d_reclen);
 165         }
 166
 167         ASSERT(osize <= count);
 168         ASSERT((char *)op <= (char *)obuf + bufsize);
 169         ASSERT((char *)dp <= (char *)newbuf + bufsize);
 170
 171         if ((error = copyout(obuf, buf, osize)) < 0)
 172                 error = EFAULT;
 173 out:
 174         kmem_free(newbuf, bufsize);
 175         kmem_free(obuf, bufsize);
 176
 177         if (error) {
 178                 releasef(fd);
 179                 return (set_errno(error));
 180         }
 181
 182         releasef(fd);
 183         return (osize);
 184 }
 185
 186 #endif  /* _SYSCALL32 || _ILP32 */
 187
 188 int
 189 getdents64(int fd, void *buf, size_t count)
 190 {
 191         vnode_t *vp;
 192         file_t *fp;
 193         struct uio auio;
 194         struct iovec aiov;
 195         register int error;
 196         int sink;
 197
 198         if (count < sizeof (struct dirent64))
 199                 return (set_errno(EINVAL));
 200
 201         /*
 202          * Don't let the user overcommit kernel resources.
 203          */
 204         if (count > MAXGETDENTS_SIZE)
 205                 count = MAXGETDENTS_SIZE;
 206
 207         if ((fp = getf(fd)) == NULL)
 208                 return (set_errno(EBADF));
 209         vp = fp->f_vnode;
 210         if (vp->v_type != VDIR) {
 211                 releasef(fd);
 212                 return (set_errno(ENOTDIR));
 213         }
 214         if (!(fp->f_flag & FREAD)) {
 215                 releasef(fd);
 216                 return (set_errno(EBADF));
 217         }
 218         aiov.iov_base = buf;
 219         aiov.iov_len = count;
 220         auio.uio_iov = &aiov;
 221         auio.uio_iovcnt = 1;
 222         auio.uio_loffset = fp->f_offset;
 223         auio.uio_segflg = UIO_USERSPACE;
 224         auio.uio_resid = count;
 225         auio.uio_fmode = 0;
 226         auio.uio_extflg = UIO_COPY_CACHED;
 227         (void) fop_rwlock(vp, V_WRITELOCK_FALSE, NULL);
 228         error = fop_readdir(vp, &auio, fp->f_cred, &sink, NULL, 0);
 229         fop_rwunlock(vp, V_WRITELOCK_FALSE, NULL);
 230         if (error) {
 231                 releasef(fd);
 232                 return (set_errno(error));
 233         }
 234         count = count - auio.uio_resid;
 235         fp->f_offset = auio.uio_loffset;
 236         releasef(fd);
 237         return (count);
 238 }