xref: /freebsd/stand/libsa/ufsread.c (revision f81cdf24ba5436367377f7c8e8f51f6df2a75ca7)
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 #include <ufs/ufs/dinode.h>
48 #include <ufs/ufs/dir.h>
49 #include <ufs/ffs/fs.h>
50 
51 #ifdef UFS_SMALL_CGBASE
52 /* XXX: Revert to old (broken for over 1.5Tb filesystems) version of cgbase
53    (see sys/ufs/ffs/fs.h rev 1.39) so that small boot loaders (e.g. boot2) can
54    support both UFS1 and UFS2. */
55 #undef cgbase
56 #define cgbase(fs, c)   ((ufs2_daddr_t)((fs)->fs_fpg * (c)))
57 #endif
58 
59 typedef	uint32_t	ufs_ino_t;
60 
61 /*
62  * We use 4k `virtual' blocks for filesystem data, whatever the actual
63  * filesystem block size. FFS blocks are always a multiple of 4k.
64  */
65 #define VBLKSHIFT	12
66 #define VBLKSIZE	(1 << VBLKSHIFT)
67 #define VBLKMASK	(VBLKSIZE - 1)
68 #define DBPERVBLK	(VBLKSIZE / DEV_BSIZE)
69 #define INDIRPERVBLK(fs) (NINDIR(fs) / ((fs)->fs_bsize >> VBLKSHIFT))
70 #define IPERVBLK(fs)	(INOPB(fs) / ((fs)->fs_bsize >> VBLKSHIFT))
71 #define INO_TO_VBA(fs, ipervblk, x) \
72     (fsbtodb(fs, cgimin(fs, ino_to_cg(fs, x))) + \
73     (((x) % (fs)->fs_ipg) / (ipervblk) * DBPERVBLK))
74 #define INO_TO_VBO(ipervblk, x) ((x) % ipervblk)
75 #define FS_TO_VBA(fs, fsb, off) (fsbtodb(fs, fsb) + \
76     ((off) / VBLKSIZE) * DBPERVBLK)
77 #define FS_TO_VBO(fs, fsb, off) ((off) & VBLKMASK)
78 
79 /* Buffers that must not span a 64k boundary. */
80 struct dmadat {
81 	char blkbuf[VBLKSIZE];	/* filesystem blocks */
82 	char indbuf[VBLKSIZE];	/* indir blocks */
83 	char sbbuf[SBLOCKSIZE];	/* superblock */
84 	char secbuf[DEV_BSIZE];	/* for MBR/disklabel */
85 };
86 static struct dmadat *dmadat;
87 
88 static ufs_ino_t lookup(const char *);
89 static ssize_t fsread(ufs_ino_t, void *, size_t);
90 
91 static uint8_t ls, dsk_meta;
92 static uint32_t fs_off;
93 
94 static __inline uint8_t
95 fsfind(const char *name, ufs_ino_t * ino)
96 {
97 	static char buf[DEV_BSIZE];
98 	static struct direct d;
99 	char *s;
100 	ssize_t n;
101 
102 	fs_off = 0;
103 	while ((n = fsread(*ino, buf, DEV_BSIZE)) > 0)
104 		for (s = buf; s < buf + DEV_BSIZE;) {
105 			memcpy(&d, s, sizeof(struct direct));
106 			if (ls)
107 				printf("%s ", d.d_name);
108 			else if (!strcmp(name, d.d_name)) {
109 				*ino = d.d_ino;
110 				return d.d_type;
111 			}
112 			s += d.d_reclen;
113 		}
114 	if (n != -1 && ls)
115 		printf("\n");
116 	return 0;
117 }
118 
119 static ufs_ino_t
120 lookup(const char *path)
121 {
122 	static char name[UFS_MAXNAMLEN + 1];
123 	const char *s;
124 	ufs_ino_t ino;
125 	ssize_t n;
126 	uint8_t dt;
127 
128 	ino = UFS_ROOTINO;
129 	dt = DT_DIR;
130 	for (;;) {
131 		if (*path == '/')
132 			path++;
133 		if (!*path)
134 			break;
135 		for (s = path; *s && *s != '/'; s++);
136 		if ((n = s - path) > UFS_MAXNAMLEN)
137 			return 0;
138 		ls = *path == '?' && n == 1 && !*s;
139 		memcpy(name, path, n);
140 		name[n] = 0;
141 		if (dt != DT_DIR) {
142 			printf("%s: not a directory.\n", name);
143 			return (0);
144 		}
145 		if ((dt = fsfind(name, &ino)) <= 0)
146 			break;
147 		path = s;
148 	}
149 	return dt == DT_REG ? ino : 0;
150 }
151 
152 /*
153  * Possible superblock locations ordered from most to least likely.
154  */
155 static int sblock_try[] = SBLOCKSEARCH;
156 
157 #if defined(UFS2_ONLY)
158 #define DIP(field) dp2.field
159 #elif defined(UFS1_ONLY)
160 #define DIP(field) dp1.field
161 #else
162 #define DIP(field) fs.fs_magic == FS_UFS1_MAGIC ? dp1.field : dp2.field
163 #endif
164 
165 static ssize_t
166 fsread_size(ufs_ino_t inode, void *buf, size_t nbyte, size_t *fsizep)
167 {
168 #ifndef UFS2_ONLY
169 	static struct ufs1_dinode dp1;
170 	ufs1_daddr_t addr1;
171 #endif
172 #ifndef UFS1_ONLY
173 	static struct ufs2_dinode dp2;
174 #endif
175 	static struct fs fs;
176 	static ufs_ino_t inomap;
177 	char *blkbuf;
178 	void *indbuf;
179 	char *s;
180 	size_t n, nb, size, off, vboff;
181 	ufs_lbn_t lbn;
182 	ufs2_daddr_t addr2, vbaddr;
183 	static ufs2_daddr_t blkmap, indmap;
184 	u_int u;
185 
186 	/* Basic parameter validation. */
187 	if ((buf == NULL && nbyte != 0) || dmadat == NULL)
188 		return (-1);
189 
190 	blkbuf = dmadat->blkbuf;
191 	indbuf = dmadat->indbuf;
192 
193 	/*
194 	 * Force probe if inode is zero to ensure we have a valid fs, otherwise
195 	 * when probing multiple paritions, reads from subsequent parititions
196 	 * will incorrectly succeed.
197 	 */
198 	if (!dsk_meta || inode == 0) {
199 		inomap = 0;
200 		dsk_meta = 0;
201 		for (n = 0; sblock_try[n] != -1; n++) {
202 			if (dskread(dmadat->sbbuf, sblock_try[n] / DEV_BSIZE,
203 			    SBLOCKSIZE / DEV_BSIZE))
204 				return -1;
205 			memcpy(&fs, dmadat->sbbuf, sizeof(struct fs));
206 			if ((
207 #if defined(UFS1_ONLY)
208 			    fs.fs_magic == FS_UFS1_MAGIC
209 #elif defined(UFS2_ONLY)
210 			    (fs.fs_magic == FS_UFS2_MAGIC &&
211 			    fs.fs_sblockloc == sblock_try[n])
212 #else
213 			    fs.fs_magic == FS_UFS1_MAGIC ||
214 			    (fs.fs_magic == FS_UFS2_MAGIC &&
215 			    fs.fs_sblockloc == sblock_try[n])
216 #endif
217 			    ) &&
218 			    fs.fs_bsize <= MAXBSIZE &&
219 			    fs.fs_bsize >= (int32_t)sizeof(struct fs))
220 				break;
221 		}
222 		if (sblock_try[n] == -1) {
223 			return -1;
224 		}
225 		dsk_meta++;
226 	} else
227 		memcpy(&fs, dmadat->sbbuf, sizeof(struct fs));
228 	if (!inode)
229 		return 0;
230 	if (inomap != inode) {
231 		n = IPERVBLK(&fs);
232 		if (dskread(blkbuf, INO_TO_VBA(&fs, n, inode), DBPERVBLK))
233 			return -1;
234 		n = INO_TO_VBO(n, inode);
235 #if defined(UFS1_ONLY)
236 		memcpy(&dp1, (struct ufs1_dinode *)(void *)blkbuf + n,
237 		    sizeof(dp1));
238 #elif defined(UFS2_ONLY)
239 		memcpy(&dp2, (struct ufs2_dinode *)(void *)blkbuf + n,
240 		    sizeof(dp2));
241 #else
242 		if (fs.fs_magic == FS_UFS1_MAGIC)
243 			memcpy(&dp1, (struct ufs1_dinode *)(void *)blkbuf + n,
244 			    sizeof(dp1));
245 		else
246 			memcpy(&dp2, (struct ufs2_dinode *)(void *)blkbuf + n,
247 			    sizeof(dp2));
248 #endif
249 		inomap = inode;
250 		fs_off = 0;
251 		blkmap = indmap = 0;
252 	}
253 	s = buf;
254 	size = DIP(di_size);
255 	n = size - fs_off;
256 	if (nbyte > n)
257 		nbyte = n;
258 	nb = nbyte;
259 	while (nb) {
260 		lbn = lblkno(&fs, fs_off);
261 		off = blkoff(&fs, fs_off);
262 		if (lbn < UFS_NDADDR) {
263 			addr2 = DIP(di_db[lbn]);
264 		} else if (lbn < UFS_NDADDR + NINDIR(&fs)) {
265 			n = INDIRPERVBLK(&fs);
266 			addr2 = DIP(di_ib[0]);
267 			u = (u_int)(lbn - UFS_NDADDR) / n * DBPERVBLK;
268 			vbaddr = fsbtodb(&fs, addr2) + u;
269 			if (indmap != vbaddr) {
270 				if (dskread(indbuf, vbaddr, DBPERVBLK))
271 					return -1;
272 				indmap = vbaddr;
273 			}
274 			n = (lbn - UFS_NDADDR) & (n - 1);
275 #if defined(UFS1_ONLY)
276 			memcpy(&addr1, (ufs1_daddr_t *)indbuf + n,
277 			    sizeof(ufs1_daddr_t));
278 			addr2 = addr1;
279 #elif defined(UFS2_ONLY)
280 			memcpy(&addr2, (ufs2_daddr_t *)indbuf + n,
281 			    sizeof(ufs2_daddr_t));
282 #else
283 			if (fs.fs_magic == FS_UFS1_MAGIC) {
284 				memcpy(&addr1, (ufs1_daddr_t *)indbuf + n,
285 				    sizeof(ufs1_daddr_t));
286 				addr2 = addr1;
287 			} else
288 				memcpy(&addr2, (ufs2_daddr_t *)indbuf + n,
289 				    sizeof(ufs2_daddr_t));
290 #endif
291 		} else
292 			return -1;
293 		vbaddr = fsbtodb(&fs, addr2) + (off >> VBLKSHIFT) * DBPERVBLK;
294 		vboff = off & VBLKMASK;
295 		n = sblksize(&fs, (off_t)size, lbn) - (off & ~VBLKMASK);
296 		if (n > VBLKSIZE)
297 			n = VBLKSIZE;
298 		if (blkmap != vbaddr) {
299 			if (dskread(blkbuf, vbaddr, n >> DEV_BSHIFT))
300 				return -1;
301 			blkmap = vbaddr;
302 		}
303 		n -= vboff;
304 		if (n > nb)
305 			n = nb;
306 		memcpy(s, blkbuf + vboff, n);
307 		s += n;
308 		fs_off += n;
309 		nb -= n;
310 	}
311 
312 	if (fsizep != NULL)
313 		*fsizep = size;
314 
315 	return nbyte;
316 }
317 
318 static ssize_t
319 fsread(ufs_ino_t inode, void *buf, size_t nbyte)
320 {
321 
322 	return fsread_size(inode, buf, nbyte, NULL);
323 }
324 
325