xref: /illumos-gate/usr/src/stand/lib/fs/nfs/getdents3.c (revision f3041bfa)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  *
26  *  Stuff relating to NFSv3 directory reading ...
27  */
28 
29 #pragma ident	"%Z%%M%	%I%	%E% SMI"
30 
31 #include <rpc/types.h>
32 #include <rpc/auth.h>
33 #include <rpc/xdr.h>
34 #include "clnt.h"
35 #include <rpc/rpc_msg.h>
36 #include <sys/t_lock.h>
37 #include "nfs_inet.h"
38 #include <rpc/rpc.h>
39 #include "brpc.h"
40 #include <rpcsvc/nfs_prot.h>
41 #include <sys/types.h>
42 #include <sys/stat.h>
43 #include <sys/bootvfs.h>
44 #include <sys/sysmacros.h>
45 #include "socket_inet.h"
46 #include <sys/salib.h>
47 #include <sys/bootdebug.h>
48 
49 #define	MAXDENTS 16
50 #define	MINSIZ 20
51 
52 /*
53  * Boot needs to be cleaned up to use either dirent32 or dirent64,
54  * in the meantime use dirent_t and always round to 8 bytes
55  */
56 #define	BDIRENT_RECLEN(namelen) \
57 	((offsetof(dirent_t, d_name[0]) + 1 + (namelen) + 7) & ~ 7)
58 
59 #define	dprintf	if (boothowto & RB_DEBUG) printf
60 
61 /*
62  *  Get directory entries:
63  *
64  *	Uses the nfs "READDIR" operation to read directory entries
65  *	into a local buffer.  These are then translated into file
66  *	system independent "dirent" structs and returned in the
67  *	caller's buffer.  Returns the number of entries converted
68  *	(-1 if there's an error).
69  *
70  *	Although the xdr functions can allocate memory, we have
71  *	a limited heap so we allocate our own space,
72  *	assuming the worst case of 256 byte names.
73  *	This is a space hog in our local buffer, so we want
74  *	the number of buffers to be small. To make sure we don't
75  *	get more names than we can handle, we tell the rpc
76  *	routine that we only have space for MAXDENT names if
77  *	they are all the minimum size. This keeps the return
78  *	packet unfragmented, but may result in lots of reads
79  *	to process a large directory. Since this is standalone
80  *	we don't worry about speed. With MAXDENTs at 16, the
81  *	local buffer is 4k.
82  */
83 
84 int
85 nfs3getdents(struct nfs_file *nfp, struct dirent *dep, unsigned size)
86 {
87 	int cnt = 0;
88 	entry3 *ep;
89 	READDIR3args rda;
90 	READDIR3res  res;
91 	enum clnt_stat status;
92 	struct {
93 		entry3 etlist[MAXDENTS];
94 		char names[MAXDENTS][NFS_MAXNAMLEN+1];
95 	} rdbuf;
96 	int j;
97 	struct timeval zero_timeout = {0, 0};   /* default */
98 
99 	bzero((caddr_t)&res, sizeof (res));
100 	bzero((caddr_t)&rda, sizeof (rda));
101 	bzero((caddr_t)rdbuf.etlist, sizeof (rdbuf.etlist));
102 
103 	rda.dir.data.data_len = nfp->fh.fh3.len;
104 	rda.dir.data.data_val = nfp->fh.fh3.data;
105 	rda.cookie = nfp->cookie.cookie3;
106 
107 	while (!res.READDIR3res_u.resok.reply.eof) {
108 		/*
109 		 *  Keep issuing nfs calls until EOF is reached on
110 		 *  the directory or the user buffer is filled.
111 		 */
112 
113 		for (j = 0; j < MAXDENTS; j++) {
114 			/*
115 			 *  Link our buffers together for the benefit of
116 			 *  XDR.  We do this each time we issue the rpc call
117 			 *  JIC the xdr decode
118 			 *  routines screw up the linkage!
119 			 */
120 
121 			rdbuf.etlist[j].name = rdbuf.names[(MAXDENTS-1) - j];
122 			rdbuf.etlist[j].nextentry =
123 				(j < (MAXDENTS-1)) ? &rdbuf.etlist[j+1] : 0;
124 		}
125 
126 		res.READDIR3res_u.resok.reply.entries = rdbuf.etlist;
127 		/*
128 		 * Cannot give the whole buffer unless every name is
129 		 * 256 bytes! Assume the worst case of all 1 byte names.
130 		 * This results in MINSIZ bytes/name in the xdr stream.
131 		 */
132 		rda.count = sizeof (res) + MAXDENTS*MINSIZ;
133 		bzero((caddr_t)rdbuf.names, sizeof (rdbuf.names));
134 
135 		status = CLNT_CALL(root_CLIENT, NFSPROC3_READDIR,
136 		    xdr_READDIR3args, (caddr_t)&rda,
137 		    xdr_READDIR3res, (caddr_t)&res, zero_timeout);
138 
139 		if (status != RPC_SUCCESS) {
140 			dprintf("nfs3_getdents: RPC error\n");
141 			return (-1);
142 		}
143 		if (res.status != NFS3_OK) {
144 			/*
145 			 *  The most common failure here would be trying to
146 			 *  issue a getdents call on a non-directory!
147 			 */
148 
149 			nfs3_error(res.status);
150 			return (-1);
151 		}
152 
153 		for (ep = rdbuf.etlist; ep; ep = ep->nextentry) {
154 			/*
155 			 *  Step thru all entries returned by NFS, converting
156 			 *  to the cannonical form and copying out to the
157 			 *  user's buffer.
158 			 */
159 
160 			int n;
161 
162 			/*
163 			 * catch the case user called at EOF
164 			 */
165 			if ((n = strlen(ep->name)) == 0)
166 				return (cnt);
167 
168 			n = BDIRENT_RECLEN(n);
169 
170 			if (n > size)
171 				return (cnt);
172 			size -= n;
173 
174 			(void) strcpy(dep->d_name, ep->name);
175 			dep->d_ino = ep->fileid;
176 			dep->d_off = (off_t)ep->cookie;
177 			dep->d_reclen = (ushort_t)n;
178 
179 			dep = (struct dirent *)((char *)dep + n);
180 			rda.cookie = ep->cookie;
181 			nfp->cookie.cookie3 = ep->cookie;
182 			cnt++;
183 		}
184 	}
185 
186 	return (cnt);
187 }
188