xref: /titanic_41/usr/src/uts/common/syscall/getdents.c (revision b3697b90e692e3e5d859fb77d285d4c056d99eda)
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 VOP_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) 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 	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) VOP_RWLOCK(vp, V_WRITELOCK_FALSE, NULL);
228 	error = VOP_READDIR(vp, &auio, fp->f_cred, &sink, NULL, 0);
229 	VOP_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 }
239