xref: /illumos-gate/usr/src/cmd/fs.d/pcfs/fstyp/fstyp.c (revision c719c59a)
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 
27 /*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 /*
31  * Portions of this source code were derived from Berkeley 4.3 BSD
32  * under license from the Regents of the University of California.
33  */
34 
35 #pragma ident	"%Z%%M%	%I%	%E% SMI"
36 
37 /*
38  * fstyp
39  *
40  * Designed to work with block devices (e.g., /dev/diskette), not
41  * raw devices (e.g., /dev/rdiskette)
42  */
43 #include <sys/param.h>
44 #include <sys/types.h>
45 #include <sys/mntent.h>
46 #include <errno.h>
47 #include <sys/fs/pc_fs.h>
48 #include <sys/fs/pc_label.h>
49 #include <sys/stat.h>
50 #include <sys/vfs.h>
51 
52 #include <stdio.h>
53 #include <sys/mnttab.h>
54 
55 #include <locale.h>
56 
57 extern offset_t llseek();
58 
59 
60 #define	PC_BPSEC(a)	((a[12]<<8)+a[11])	/* bytes per sector */
61 #define	PC_SPC(a)	(a[13])			/* sectors per cluster */
62 #define	PC_RESSEC(a)	((a[15]<<8)+a[14])	/* reserved sectors */
63 #define	PC_NFAT(a)	(a[16])			/* number of fats */
64 #define	PC_NROOTENT(a)	((a[18]<<8)+a[17])	/* number of root dir entries */
65 #define	PC_MEDIA(a)	(a[21])			/* media descriptor */
66 #define	PC_SPT(a)	((a[25]<<8)+a[24])	/* sectors per track */
67 #define	PC_NHEAD(a)	((a[27]<<8)+a[26])	/* number of heads */
68 #define	PC_HIDSEC(a)	((a[29]<<8)+a[28])	/* number of hidden sectors */
69 #define	PC_DRVNUM(a)	(a[36])			/* drive number */
70 #define	PC_LAB_ADDR(a)	(&a[43])		/* addr of volume label */
71 #define	LABEL_SIZE 11				/* size of volume label */
72 
73 /*
74  * Parse out all the following forms as unsigned quantities. It would
75  * not be unusual for them to be large enough that the high bit would be
76  * set and they would then be misinterpreted as negative quantities.
77  *
78  * The values are:
79  *	number of sectors
80  *	big number of sectors (MSDOS4.0 and later)
81  *	sectors/FAT
82  *	big sectors/FAT (FAT32 only)
83  */
84 #define	PC_NSEC(a)	((unsigned short)((a[20]<<8)+a[19]))
85 #define	PC_BIGNSEC(a)	((unsigned)((a[35]<<24)+(a[34]<<16)+(a[33]<<8)+a[32]))
86 #define	PC_SPF(a)	((unsigned short)((a[23]<<8)+a[22]))
87 #define	PC_BIGSPF(a)	((unsigned)((a[39]<<24)+(a[38]<<16)+(a[37]<<8)+a[36]))
88 
89 /*
90  * Boolean macros
91  */
92 #define	PC_EXTSIG(a)	(a[38] == 0x29)	/* do we have an extended BPB? */
93 #define	PC_EXTSIG32(a)	(a[66] == 0x29)	/* do we have FAT32 w/ extended BPB? */
94 
95 int	vflag = 0;		/* verbose output */
96 int	errflag = 0;
97 char	*cbasename;
98 char	*special;
99 char	*fstype;
100 
101 static void usage(void);
102 static void dumpfs(char *name);
103 static int valid_media(unsigned char media_type);
104 
105 int
106 main(int argc, char *argv[])
107 {
108 	int	c;
109 
110 	(void) setlocale(LC_ALL, "");
111 #if !defined(TEXT_DOMAIN)
112 #define	TEXT_DOMAIN "SYS_TEST"
113 #endif
114 	(void) textdomain(TEXT_DOMAIN);
115 
116 	cbasename = argv[0];
117 	while ((c = getopt(argc, argv, "v")) != EOF) {
118 		switch (c) {
119 
120 		case 'v':		/* dump super block */
121 			vflag++;
122 			break;
123 
124 		case '?':
125 			errflag++;
126 		}
127 	}
128 	if (errflag || argc <= optind) {
129 		usage();
130 		exit(31+1);
131 	}
132 	special = argv[optind];
133 	dumpfs(special);
134 
135 	return (0);
136 }
137 
138 
139 static void
140 usage(void)
141 {
142 	(void) fprintf(stderr, gettext("pcfs usage: fstyp [-v] special\n"));
143 }
144 
145 static void
146 dumpfs(char *name)
147 {
148 	unsigned char	buf[DEV_BSIZE];
149 	char	label[LABEL_SIZE+1];
150 	unsigned char	media;
151 
152 	close(0);
153 	if (open(name, 0) != 0) {
154 		perror(name);
155 		exit(1);
156 	}
157 	llseek(0, (offset_t)0, 0);
158 	if (read(0, buf, sizeof (buf)) != sizeof (buf)) {
159 
160 		/*
161 		 * As an fstyp command, this can get called for a device from
162 		 * any filesystem (or for that matter, a bogus device). The
163 		 * read() returns EINVAL when it's not a pcfs. In this case,
164 		 * don't print an error message.
165 		 */
166 		if (errno != EINVAL) {
167 			perror(name);
168 		}
169 		exit(1);
170 	}
171 
172 	media = (unsigned char)PC_MEDIA(buf);
173 	if (!valid_media(media))
174 		exit(31+1);
175 	if (!well_formed(buf))
176 		exit(31+1);
177 	printf("%s\n", "pcfs");
178 
179 	if (!vflag)
180 		exit(0);
181 
182 	printf("Bytes Per Sector  %d\t\tSectors Per Cluster    %d\n",
183 		(unsigned short)PC_BPSEC(buf), (unsigned char)PC_SPC(buf));
184 	printf("Reserved Sectors  %d\t\tNumber of FATs         %d\n",
185 		(unsigned short)PC_RESSEC(buf), (unsigned char)PC_NFAT(buf));
186 	printf("Root Dir Entries  %d\t\tNumber of Sectors      %d\n",
187 		(unsigned short)PC_NROOTENT(buf), (unsigned short)PC_NSEC(buf));
188 	printf("Sectors Per FAT   %d\t\tSectors Per Track      %d\n",
189 		(unsigned short)PC_SPF(buf), (unsigned short)PC_SPT(buf));
190 	printf("Number of Heads   %d\t\tNumber Hidden Sectors  %d\n",
191 		(unsigned short)PC_NHEAD(buf), (unsigned short)PC_HIDSEC(buf));
192 	strncpy(label, PC_LAB_ADDR(buf), LABEL_SIZE);
193 	label[LABEL_SIZE+1] = 0;
194 	printf("Volume Label: %s\n", label);
195 	printf("Drive Number: 0x%x\n", (unsigned char)PC_DRVNUM(buf));
196 	printf("Media Type: 0x%x   ", media);
197 
198 	switch (media) {
199 	case MD_FIXED:
200 		printf("\"Fixed\" Disk\n");
201 		break;
202 	case SS8SPT:
203 		printf("Single Sided, 8 Sectors Per Track\n");
204 		break;
205 	case DS8SPT:
206 		printf("Double Sided, 8 Sectors Per Track\n");
207 		break;
208 	case SS9SPT:
209 		printf("Single Sided, 9 Sectors Per Track\n");
210 		break;
211 	case DS9SPT:
212 		printf("Double Sided, 9 Sectors Per Track\n");
213 		break;
214 	case DS18SPT:
215 		printf("Double Sided, 18 Sectors Per Track\n");
216 		break;
217 	case DS9_15SPT:
218 		printf("Double Sided, 9-15 Sectors Per Track\n");
219 		break;
220 	default:
221 		printf("Unknown Media Type\n");
222 	}
223 
224 	close(0);
225 	exit(0);
226 }
227 
228 static int
229 valid_media(unsigned char media_type)
230 {
231 	switch (media_type) {
232 
233 	case MD_FIXED:
234 	case SS8SPT:
235 	case DS8SPT:
236 	case SS9SPT:
237 	case DS9SPT:
238 	case DS18SPT:
239 	case DS9_15SPT:
240 		return (1);
241 	default:
242 		return (0);
243 	}
244 }
245 
246 int
247 well_formed(unsigned char bs[])
248 {
249 	int fatmatch;
250 
251 	if (PC_EXTSIG(bs)) {
252 		fatmatch = ((bs[PCFS_TYPESTRING_OFFSET16] == 'F' &&
253 			bs[PCFS_TYPESTRING_OFFSET16 + 1] == 'A' &&
254 			bs[PCFS_TYPESTRING_OFFSET16 + 2] == 'T') &&
255 			(PC_SPF(bs) > 0) &&
256 			((PC_NSEC(bs) == 0 && PC_BIGNSEC(bs) > 0) ||
257 			    PC_NSEC(bs) > 0));
258 	} else if (PC_EXTSIG32(bs)) {
259 		fatmatch = ((bs[PCFS_TYPESTRING_OFFSET32] == 'F' &&
260 			bs[PCFS_TYPESTRING_OFFSET32 + 1] == 'A' &&
261 			bs[PCFS_TYPESTRING_OFFSET32 + 2] == 'T') &&
262 			(PC_SPF(bs) == 0 && PC_BIGSPF(bs) > 0) &&
263 			((PC_NSEC(bs) == 0 && PC_BIGNSEC(bs) > 0) ||
264 			    PC_NSEC(bs) > 0));
265 	} else {
266 		fatmatch = (PC_NSEC(bs) > 0 && PC_SPF(bs) > 0);
267 	}
268 
269 	return (fatmatch && PC_BPSEC(bs) > 0 && PC_BPSEC(bs) % 512 == 0 &&
270 		PC_SPC(bs) > 0 && PC_RESSEC(bs) >= 1 && PC_NFAT(bs) > 0);
271 }
272