xref: /illumos-gate/usr/src/stand/lib/fs/nfs/getdents.c (revision 45ede40b2394db7967e59f19288fae9b62efd4aa)
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 directory reading ...
27  */
28 
29 #include <rpc/types.h>
30 #include <rpc/auth.h>
31 #include <rpc/xdr.h>
32 #include "clnt.h"
33 #include <rpc/rpc_msg.h>
34 #include <sys/t_lock.h>
35 #include "nfs_inet.h"
36 #include <rpc/rpc.h>
37 #include "brpc.h"
38 #include <rpcsvc/nfs_prot.h>
39 #include <sys/types.h>
40 #include <sys/stat.h>
41 #include <sys/bootvfs.h>
42 #include <sys/sysmacros.h>
43 #include "socket_inet.h"
44 #include <sys/salib.h>
45 #include <sys/bootdebug.h>
46 
47 #define	MAXDENTS 16
48 #define	MINSIZ 20
49 
50 /*
51  * Boot needs to be cleaned up to use either dirent32 or dirent64,
52  * in the meantime use dirent_t and always round to 8 bytes
53  */
54 #define	BDIRENT_RECLEN(namelen) \
55 	((offsetof(dirent_t, d_name[0]) + 1 + (namelen) + 7) & ~ 7)
56 
57 #define	dprintf	if (boothowto & RB_DEBUG) printf
58 
59 /*
60  *  Get directory entries:
61  *
62  *	Uses the nfs "READDIR" operation to read directory entries
63  *	into a local buffer.  These are then translated into file
64  *	system independent "dirent" structs and returned in the
65  *	caller's buffer.  Returns the number of entries converted
66  *	(-1 if there's an error).
67  *
68  *	Although the xdr functions can allocate memory, we have
69  *	a limited heap so we allocate our own space,
70  *	assuming the worst case of 256 byte names.
71  *	This is a space hog in our local buffer, so we want
72  *	the number of buffers to be small. To make sure we don't
73  *	get more names than we can handle, we tell the rpc
74  *	routine that we only have space for MAXDENT names if
75  *	they are all the minimum size. This keeps the return
76  *	packet unfragmented, but may result in lots of reads
77  *	to process a large directory. Since this is standalone
78  *	we don't worry about speed. With MAXDENTs at 16, the
79  *	local buffer is 4k.
80  */
81 
82 int
83 nfsgetdents(struct nfs_file *nfp, struct dirent *dep, unsigned size)
84 {
85 	entry *ep;
86 	readdirargs rda;
87 	readdirres  res;
88 	enum clnt_stat status;
89 	struct {
90 		entry etlist[MAXDENTS];
91 		char names[MAXDENTS][NFS_MAXNAMLEN+1];
92 	} rdbuf;
93 	uint32_t offset;
94 	int j, cnt = 0;
95 	struct timeval zero_timeout = {0, 0};	/* default */
96 
97 	bzero((caddr_t)&res, sizeof (res));
98 	bzero((caddr_t)&rda, sizeof (rda));
99 	bzero((caddr_t)rdbuf.etlist, sizeof (rdbuf.etlist));
100 	bcopy((caddr_t)&nfp->fh.fh2, (caddr_t)&rda.dir, NFS_FHSIZE);
101 	bcopy((caddr_t)nfp->cookie.cookie2, (caddr_t)rda.cookie,
102 						sizeof (nfscookie));
103 
104 	while (!res.readdirres_u.reply.eof) {
105 		/*
106 		 *  Keep issuing nfs calls until EOF is reached on
107 		 *  the directory or the user buffer is filled.
108 		 */
109 
110 		for (j = 0; j < MAXDENTS; j++) {
111 			/*
112 			 *  Link our buffers together for the benefit of
113 			 *  XDR.  We do this each time we issue the rpc call
114 			 *  JIC the xdr decode
115 			 *  routines screw up the linkage!
116 			 */
117 
118 			rdbuf.etlist[j].name = rdbuf.names[(MAXDENTS-1) - j];
119 			rdbuf.etlist[j].nextentry =
120 				(j < (MAXDENTS-1)) ? &rdbuf.etlist[j+1] : 0;
121 		}
122 
123 		res.readdirres_u.reply.entries = rdbuf.etlist;
124 		/*
125 		 * Cannot give the whole buffer unless every name is
126 		 * 256 bytes! Assume the worst case of all 1 byte names.
127 		 * This results in MINSIZ bytes/name in the xdr stream.
128 		 */
129 		rda.count = sizeof (res) + MAXDENTS*MINSIZ;
130 		bzero((caddr_t)rdbuf.names, sizeof (rdbuf.names));
131 
132 		status = CLNT_CALL(root_CLIENT, NFSPROC_READDIR,
133 		    xdr_readdirargs, (caddr_t)&rda,
134 		    xdr_readdirres, (caddr_t)&res, zero_timeout);
135 
136 		if (status != RPC_SUCCESS) {
137 			dprintf("nfs_getdents: RPC error\n");
138 			return (-1);
139 		}
140 		if (res.status != NFS_OK) {
141 			/*
142 			 *  The most common failure here would be trying to
143 			 *  issue a getdents call on a non-directory!
144 			 */
145 
146 			nfs_error(res.status);
147 			return (-1);
148 		}
149 
150 		for (ep = rdbuf.etlist; ep; ep = ep->nextentry) {
151 			/*
152 			 *  Step thru all entries returned by NFS, converting
153 			 *  to the cannonical form and copying out to the
154 			 *  user's buffer.
155 			 */
156 
157 			int n;
158 
159 			/*
160 			 * catch the case user called at EOF
161 			 */
162 			if ((n = strlen(ep->name)) == 0)
163 				return (cnt);
164 
165 			n = BDIRENT_RECLEN(n);
166 
167 			if (n > size)
168 				return (cnt);
169 			size -= n;
170 
171 			(void) strlcpy(dep->d_name, ep->name,
172 			    strlen(ep->name) + 1);
173 			dep->d_ino = ep->fileid;
174 			bcopy(ep->cookie, &offset, sizeof (nfscookie));
175 			dep->d_off = offset;
176 			dep->d_reclen = (ushort_t)n;
177 
178 			dep = (struct dirent *)((char *)dep + n);
179 			bcopy(ep->cookie, rda.cookie, sizeof (nfscookie));
180 			bcopy(ep->cookie, nfp->cookie.cookie2,
181 							sizeof (nfscookie));
182 			cnt++;
183 		}
184 	}
185 
186 	return (cnt);
187 }
188