xref: /freebsd/stand/libsa/ufsread.c (revision b0d29bc47dba79f6f38e67eabadfb4b32ffd9390)
1 /*-
2  * Copyright (c) 2002 McAfee, Inc.
3  * All rights reserved.
4  *
5  * This software was developed for the FreeBSD Project by Marshall
6  * Kirk McKusick and McAfee Research,, the Security Research Division of
7  * McAfee, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as
8  * part of the DARPA CHATS research program
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 /*-
32  * Copyright (c) 1998 Robert Nordier
33  * All rights reserved.
34  *
35  * Redistribution and use in source and binary forms are freely
36  * permitted provided that the above copyright notice and this
37  * paragraph and the following disclaimer are duplicated in all
38  * such forms.
39  *
40  * This software is provided "AS IS" and without any express or
41  * implied warranties, including, without limitation, the implied
42  * warranties of merchantability and fitness for a particular
43  * purpose.
44  */
45 
46 #include <sys/cdefs.h>
47 __FBSDID("$FreeBSD$");
48 
49 #include <ufs/ufs/dinode.h>
50 #include <ufs/ufs/dir.h>
51 #include <ufs/ffs/fs.h>
52 
53 #ifdef UFS_SMALL_CGBASE
54 /* XXX: Revert to old (broken for over 1.5Tb filesystems) version of cgbase
55    (see sys/ufs/ffs/fs.h rev 1.39) so that small boot loaders (e.g. boot2) can
56    support both UFS1 and UFS2. */
57 #undef cgbase
58 #define cgbase(fs, c)   ((ufs2_daddr_t)((fs)->fs_fpg * (c)))
59 #endif
60 
61 typedef	uint32_t	ufs_ino_t;
62 
63 /*
64  * We use 4k `virtual' blocks for filesystem data, whatever the actual
65  * filesystem block size. FFS blocks are always a multiple of 4k.
66  */
67 #define VBLKSHIFT	12
68 #define VBLKSIZE	(1 << VBLKSHIFT)
69 #define VBLKMASK	(VBLKSIZE - 1)
70 #define DBPERVBLK	(VBLKSIZE / DEV_BSIZE)
71 #define INDIRPERVBLK(fs) (NINDIR(fs) / ((fs)->fs_bsize >> VBLKSHIFT))
72 #define IPERVBLK(fs)	(INOPB(fs) / ((fs)->fs_bsize >> VBLKSHIFT))
73 #define INO_TO_VBA(fs, ipervblk, x) \
74     (fsbtodb(fs, cgimin(fs, ino_to_cg(fs, x))) + \
75     (((x) % (fs)->fs_ipg) / (ipervblk) * DBPERVBLK))
76 #define INO_TO_VBO(ipervblk, x) ((x) % ipervblk)
77 #define FS_TO_VBA(fs, fsb, off) (fsbtodb(fs, fsb) + \
78     ((off) / VBLKSIZE) * DBPERVBLK)
79 #define FS_TO_VBO(fs, fsb, off) ((off) & VBLKMASK)
80 
81 /* Buffers that must not span a 64k boundary. */
82 struct dmadat {
83 	char blkbuf[VBLKSIZE];	/* filesystem blocks */
84 	char indbuf[VBLKSIZE];	/* indir blocks */
85 	char sbbuf[SBLOCKSIZE];	/* superblock */
86 	char secbuf[DEV_BSIZE];	/* for MBR/disklabel */
87 };
88 static struct dmadat *dmadat;
89 
90 static ufs_ino_t lookup(const char *);
91 static ssize_t fsread(ufs_ino_t, void *, size_t);
92 
93 static uint8_t ls, dsk_meta;
94 static uint32_t fs_off;
95 
96 static __inline uint8_t
97 fsfind(const char *name, ufs_ino_t * ino)
98 {
99 	static char buf[DEV_BSIZE];
100 	static struct direct d;
101 	char *s;
102 	ssize_t n;
103 
104 	fs_off = 0;
105 	while ((n = fsread(*ino, buf, DEV_BSIZE)) > 0)
106 		for (s = buf; s < buf + DEV_BSIZE;) {
107 			memcpy(&d, s, sizeof(struct direct));
108 			if (ls)
109 				printf("%s ", d.d_name);
110 			else if (!strcmp(name, d.d_name)) {
111 				*ino = d.d_ino;
112 				return d.d_type;
113 			}
114 			s += d.d_reclen;
115 		}
116 	if (n != -1 && ls)
117 		printf("\n");
118 	return 0;
119 }
120 
121 static ufs_ino_t
122 lookup(const char *path)
123 {
124 	static char name[UFS_MAXNAMLEN + 1];
125 	const char *s;
126 	ufs_ino_t ino;
127 	ssize_t n;
128 	uint8_t dt;
129 
130 	ino = UFS_ROOTINO;
131 	dt = DT_DIR;
132 	for (;;) {
133 		if (*path == '/')
134 			path++;
135 		if (!*path)
136 			break;
137 		for (s = path; *s && *s != '/'; s++);
138 		if ((n = s - path) > UFS_MAXNAMLEN)
139 			return 0;
140 		ls = *path == '?' && n == 1 && !*s;
141 		memcpy(name, path, n);
142 		name[n] = 0;
143 		if (dt != DT_DIR) {
144 			printf("%s: not a directory.\n", name);
145 			return (0);
146 		}
147 		if ((dt = fsfind(name, &ino)) <= 0)
148 			break;
149 		path = s;
150 	}
151 	return dt == DT_REG ? ino : 0;
152 }
153 
154 /*
155  * Possible superblock locations ordered from most to least likely.
156  */
157 static int sblock_try[] = SBLOCKSEARCH;
158 
159 #if defined(UFS2_ONLY)
160 #define DIP(field) dp2.field
161 #elif defined(UFS1_ONLY)
162 #define DIP(field) dp1.field
163 #else
164 #define DIP(field) fs.fs_magic == FS_UFS1_MAGIC ? dp1.field : dp2.field
165 #endif
166 
167 static ssize_t
168 fsread_size(ufs_ino_t inode, void *buf, size_t nbyte, size_t *fsizep)
169 {
170 #ifndef UFS2_ONLY
171 	static struct ufs1_dinode dp1;
172 	ufs1_daddr_t addr1;
173 #endif
174 #ifndef UFS1_ONLY
175 	static struct ufs2_dinode dp2;
176 #endif
177 	static struct fs fs;
178 	static ufs_ino_t inomap;
179 	char *blkbuf;
180 	void *indbuf;
181 	char *s;
182 	size_t n, nb, size, off, vboff;
183 	ufs_lbn_t lbn;
184 	ufs2_daddr_t addr2, vbaddr;
185 	static ufs2_daddr_t blkmap, indmap;
186 	u_int u;
187 
188 	/* Basic parameter validation. */
189 	if ((buf == NULL && nbyte != 0) || dmadat == NULL)
190 		return (-1);
191 
192 	blkbuf = dmadat->blkbuf;
193 	indbuf = dmadat->indbuf;
194 
195 	/*
196 	 * Force probe if inode is zero to ensure we have a valid fs, otherwise
197 	 * when probing multiple paritions, reads from subsequent parititions
198 	 * will incorrectly succeed.
199 	 */
200 	if (!dsk_meta || inode == 0) {
201 		inomap = 0;
202 		dsk_meta = 0;
203 		for (n = 0; sblock_try[n] != -1; n++) {
204 			if (dskread(dmadat->sbbuf, sblock_try[n] / DEV_BSIZE,
205 			    SBLOCKSIZE / DEV_BSIZE))
206 				return -1;
207 			memcpy(&fs, dmadat->sbbuf, sizeof(struct fs));
208 			if ((
209 #if defined(UFS1_ONLY)
210 			    fs.fs_magic == FS_UFS1_MAGIC
211 #elif defined(UFS2_ONLY)
212 			    (fs.fs_magic == FS_UFS2_MAGIC &&
213 			    fs.fs_sblockloc == sblock_try[n])
214 #else
215 			    fs.fs_magic == FS_UFS1_MAGIC ||
216 			    (fs.fs_magic == FS_UFS2_MAGIC &&
217 			    fs.fs_sblockloc == sblock_try[n])
218 #endif
219 			    ) &&
220 			    fs.fs_bsize <= MAXBSIZE &&
221 			    fs.fs_bsize >= (int32_t)sizeof(struct fs))
222 				break;
223 		}
224 		if (sblock_try[n] == -1) {
225 			return -1;
226 		}
227 		dsk_meta++;
228 	} else
229 		memcpy(&fs, dmadat->sbbuf, sizeof(struct fs));
230 	if (!inode)
231 		return 0;
232 	if (inomap != inode) {
233 		n = IPERVBLK(&fs);
234 		if (dskread(blkbuf, INO_TO_VBA(&fs, n, inode), DBPERVBLK))
235 			return -1;
236 		n = INO_TO_VBO(n, inode);
237 #if defined(UFS1_ONLY)
238 		memcpy(&dp1, (struct ufs1_dinode *)(void *)blkbuf + n,
239 		    sizeof(dp1));
240 #elif defined(UFS2_ONLY)
241 		memcpy(&dp2, (struct ufs2_dinode *)(void *)blkbuf + n,
242 		    sizeof(dp2));
243 #else
244 		if (fs.fs_magic == FS_UFS1_MAGIC)
245 			memcpy(&dp1, (struct ufs1_dinode *)(void *)blkbuf + n,
246 			    sizeof(dp1));
247 		else
248 			memcpy(&dp2, (struct ufs2_dinode *)(void *)blkbuf + n,
249 			    sizeof(dp2));
250 #endif
251 		inomap = inode;
252 		fs_off = 0;
253 		blkmap = indmap = 0;
254 	}
255 	s = buf;
256 	size = DIP(di_size);
257 	n = size - fs_off;
258 	if (nbyte > n)
259 		nbyte = n;
260 	nb = nbyte;
261 	while (nb) {
262 		lbn = lblkno(&fs, fs_off);
263 		off = blkoff(&fs, fs_off);
264 		if (lbn < UFS_NDADDR) {
265 			addr2 = DIP(di_db[lbn]);
266 		} else if (lbn < UFS_NDADDR + NINDIR(&fs)) {
267 			n = INDIRPERVBLK(&fs);
268 			addr2 = DIP(di_ib[0]);
269 			u = (u_int)(lbn - UFS_NDADDR) / n * DBPERVBLK;
270 			vbaddr = fsbtodb(&fs, addr2) + u;
271 			if (indmap != vbaddr) {
272 				if (dskread(indbuf, vbaddr, DBPERVBLK))
273 					return -1;
274 				indmap = vbaddr;
275 			}
276 			n = (lbn - UFS_NDADDR) & (n - 1);
277 #if defined(UFS1_ONLY)
278 			memcpy(&addr1, (ufs1_daddr_t *)indbuf + n,
279 			    sizeof(ufs1_daddr_t));
280 			addr2 = addr1;
281 #elif defined(UFS2_ONLY)
282 			memcpy(&addr2, (ufs2_daddr_t *)indbuf + n,
283 			    sizeof(ufs2_daddr_t));
284 #else
285 			if (fs.fs_magic == FS_UFS1_MAGIC) {
286 				memcpy(&addr1, (ufs1_daddr_t *)indbuf + n,
287 				    sizeof(ufs1_daddr_t));
288 				addr2 = addr1;
289 			} else
290 				memcpy(&addr2, (ufs2_daddr_t *)indbuf + n,
291 				    sizeof(ufs2_daddr_t));
292 #endif
293 		} else
294 			return -1;
295 		vbaddr = fsbtodb(&fs, addr2) + (off >> VBLKSHIFT) * DBPERVBLK;
296 		vboff = off & VBLKMASK;
297 		n = sblksize(&fs, (off_t)size, lbn) - (off & ~VBLKMASK);
298 		if (n > VBLKSIZE)
299 			n = VBLKSIZE;
300 		if (blkmap != vbaddr) {
301 			if (dskread(blkbuf, vbaddr, n >> DEV_BSHIFT))
302 				return -1;
303 			blkmap = vbaddr;
304 		}
305 		n -= vboff;
306 		if (n > nb)
307 			n = nb;
308 		memcpy(s, blkbuf + vboff, n);
309 		s += n;
310 		fs_off += n;
311 		nb -= n;
312 	}
313 
314 	if (fsizep != NULL)
315 		*fsizep = size;
316 
317 	return nbyte;
318 }
319 
320 static ssize_t
321 fsread(ufs_ino_t inode, void *buf, size_t nbyte)
322 {
323 
324 	return fsread_size(inode, buf, nbyte, NULL);
325 }
326 
327