Annotation of sys/compat/common/compat_dir.c, Revision 1.1.1.1
1.1 nbrk 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: }
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