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      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  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
     23  * Use is subject to license terms.
     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 #pragma ident	"@(#)getdents.c	1.22	07/10/25 SMI"
     35 
     36 #include <sys/param.h>
     37 #include <sys/isa_defs.h>
     38 #include <sys/types.h>
     39 #include <sys/inttypes.h>
     40 #include <sys/sysmacros.h>
     41 #include <sys/cred.h>
     42 #include <sys/dirent.h>
     43 #include <sys/systm.h>
     44 #include <sys/errno.h>
     45 #include <sys/vnode.h>
     46 #include <sys/file.h>
     47 #include <sys/mode.h>
     48 #include <sys/uio.h>
     49 #include <sys/filio.h>
     50 #include <sys/debug.h>
     51 #include <sys/kmem.h>
     52 #include <sys/cmn_err.h>
     53 
     54 #if defined(_SYSCALL32_IMPL) || defined(_ILP32)
     55 
     56 /*
     57  * Get directory entries in a file system-independent format.
     58  *
     59  * The 32-bit version of this function now allocates a buffer to grab the
     60  * directory entries in dirent64 formats from VOP_READDIR routines.
     61  * The dirent64 structures are converted to dirent32 structures and
     62  * copied to the user space.
     63  *
     64  * Both 32-bit and 64-bit versions of libc use getdents64() and therefore
     65  * we don't expect any major performance impact due to the extra kmem_alloc's
     66  * and copying done in this routine.
     67  */
     68 
     69 #define	MAXGETDENTS_SIZE	(64 * 1024)
     70 
     71 /*
     72  * Native 32-bit system call for non-large-file applications.
     73  */
     74 int
     75 getdents32(int fd, void *buf, size_t count)
     76 {
     77 	vnode_t *vp;
     78 	file_t *fp;
     79 	struct uio auio;
     80 	struct iovec aiov;
     81 	register int error;
     82 	int sink;
     83 	char *newbuf;
     84 	char *obuf;
     85 	int bufsize;
     86 	int osize, nsize;
     87 	struct dirent64 *dp;
     88 	struct dirent32 *op;
     89 
     90 	if (count < sizeof (struct dirent32))
     91 		return (set_errno(EINVAL));
     92 
     93 	if ((fp = getf(fd)) == NULL)
     94 		return (set_errno(EBADF));
     95 	vp = fp->f_vnode;
     96 	if (vp->v_type != VDIR) {
     97 		releasef(fd);
     98 		return (set_errno(ENOTDIR));
     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) VOP_RWLOCK(vp, V_WRITELOCK_FALSE, NULL);
    121 	error = VOP_READDIR(vp, &auio, fp->f_cred, &sink, NULL, 0);
    122 	VOP_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 	aiov.iov_base = buf;
    215 	aiov.iov_len = count;
    216 	auio.uio_iov = &aiov;
    217 	auio.uio_iovcnt = 1;
    218 	auio.uio_loffset = fp->f_offset;
    219 	auio.uio_segflg = UIO_USERSPACE;
    220 	auio.uio_resid = count;
    221 	auio.uio_fmode = 0;
    222 	auio.uio_extflg = UIO_COPY_CACHED;
    223 	(void) VOP_RWLOCK(vp, V_WRITELOCK_FALSE, NULL);
    224 	error = VOP_READDIR(vp, &auio, fp->f_cred, &sink, NULL, 0);
    225 	VOP_RWUNLOCK(vp, V_WRITELOCK_FALSE, NULL);
    226 	if (error) {
    227 		releasef(fd);
    228 		return (set_errno(error));
    229 	}
    230 	count = count - auio.uio_resid;
    231 	fp->f_offset = auio.uio_loffset;
    232 	releasef(fd);
    233 	return (count);
    234 }
    235