1 /* $OpenBSD: compat_dir.c,v 1.4 2003/08/14 16:55:24 fgsch Exp $ */
2
3 /*
4 * Copyright (c) 2000 Constantine Sapuntzakis
5 * 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. The name of the author may not be used to endorse or promote products
13 * derived from this software without specific prior written permission
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 *
26 */
27
28 #include <sys/param.h>
29 #include <sys/systm.h>
30 #include <sys/namei.h>
31 #include <sys/proc.h>
32 #include <sys/file.h>
33 #include <sys/stat.h>
34 #include <sys/filedesc.h>
35 #include <sys/ioctl.h>
36 #include <sys/kernel.h>
37 #include <sys/malloc.h>
38 #include <sys/vnode.h>
39 #include <sys/dirent.h>
40
41 #include <compat/common/compat_dir.h>
42
43 int
44 readdir_with_callback(fp, off, nbytes, appendfunc, arg)
45 struct file *fp;
46 off_t *off;
47 u_long nbytes;
48 int (*appendfunc)(void *, struct dirent *, off_t);
49 void *arg;
50 {
51 struct dirent *bdp;
52 caddr_t inp, buf;
53 int buflen;
54 struct uio auio;
55 struct iovec aiov;
56 int eofflag = 0;
57 u_long *cookies = NULL, *cookiep;
58 int ncookies = 0;
59 int error, len, reclen;
60 off_t newoff = *off;
61 struct vnode *vp;
62 struct vattr va;
63
64 if ((fp->f_flag & FREAD) == 0)
65 return (EBADF);
66
67 vp = (struct vnode *)fp->f_data;
68
69 if (vp->v_type != VDIR)
70 return (EINVAL);
71
72 if ((error = VOP_GETATTR(vp, &va, fp->f_cred, curproc)) != 0)
73 return (error);
74
75 buflen = min(MAXBSIZE, nbytes);
76 buflen = max(buflen, va.va_blocksize);
77 buf = malloc(buflen, M_TEMP, M_WAITOK);
78 error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, curproc);
79 if (error)
80 goto out;
81
82 again:
83 aiov.iov_base = buf;
84 aiov.iov_len = buflen;
85 auio.uio_iov = &aiov;
86 auio.uio_iovcnt = 1;
87 auio.uio_rw = UIO_READ;
88 auio.uio_segflg = UIO_SYSSPACE;
89 auio.uio_procp = curproc;
90 auio.uio_resid = buflen;
91 auio.uio_offset = newoff;
92
93 if (cookies) {
94 free(cookies, M_TEMP);
95 cookies = NULL;
96 }
97
98 error = VOP_READDIR(vp, &auio, fp->f_cred, &eofflag, &ncookies,
99 &cookies);
100 if (error)
101 goto out;
102
103 if ((len = buflen - auio.uio_resid) <= 0)
104 goto eof;
105
106 cookiep = cookies;
107 inp = buf;
108
109 if (cookies) {
110 /*
111 * When using cookies, the vfs has the option of reading from
112 * a different offset than that supplied (UFS truncates the
113 * offset to a block boundary to make sure that it never reads
114 * partway through a directory entry, even if the directory
115 * has been compacted).
116 */
117 while (len > 0 && ncookies > 0 && *cookiep <= newoff) {
118 bdp = (struct dirent *)inp;
119 len -= bdp->d_reclen;
120 inp += bdp->d_reclen;
121 cookiep++;
122 ncookies--;
123 }
124 }
125
126 for (; len > 0; len -= reclen, inp += reclen) {
127 if (cookiep && ncookies == 0)
128 break;
129
130 bdp = (struct dirent *)inp;
131 reclen = bdp->d_reclen;
132
133 if (len < reclen)
134 break;
135
136 if (reclen & 3) {
137 error = EFAULT;
138 goto out;
139 }
140
141 /* Skip holes */
142 if (bdp->d_fileno != 0) {
143 if ((error = (*appendfunc) (arg, bdp,
144 (cookiep) ? *cookiep : (newoff + reclen))) != 0) {
145 if (error == ENOMEM)
146 error = 0;
147 break;
148 }
149 }
150
151 if (cookiep) {
152 newoff = *cookiep++;
153 ncookies--;
154 } else
155 newoff += reclen;
156 }
157
158 if (len <= 0 && !eofflag)
159 goto again;
160
161 eof:
162 out:
163 if (error == 0)
164 *off = newoff;
165
166 if (cookies)
167 free(cookies, M_TEMP);
168
169 VOP_UNLOCK(vp, 0, curproc);
170 free(buf, M_TEMP);
171 return (error);
172 }