1 /*
2 * base_device.c
3 *
4 * Return the "base device" given a particular device; this is used to
5 * assure that we only fsck one partition on a particular drive at any
6 * one time. Otherwise, the disk heads will be seeking all over the
7 * place. If the base device can not be determined, return NULL.
8 *
9 * The base_device() function returns an allocated string which must
10 * be freed.
11 *
12 * Written by Theodore Ts'o, <tytso@mit.edu>
13 *
14 * Copyright (C) 2000 Theodore Ts'o.
15 *
16 * %Begin-Header%
17 * This file may be redistributed under the terms of the GNU Public
18 * License.
19 * %End-Header%
20 */
21 #include "config.h"
22 #include <stdio.h>
23 #if HAVE_UNISTD_H
24 #include <unistd.h>
25 #endif
26 #if HAVE_STDLIB_H
27 #include <stdlib.h>
28 #endif
29 #include <ctype.h>
30 #include <string.h>
31
32 #include "fsck.h"
33
34 /*
35 * Required for the uber-silly devfs /dev/ide/host1/bus2/target3/lun3
36 * pathames.
37 */
38 static const char *devfs_hier[] = {
39 "host", "bus", "target", "lun", 0
40 };
41
base_device(const char * device)42 char *base_device(const char *device)
43 {
44 char *str, *cp;
45 const char **hier, *disk;
46 int len;
47
48 str = malloc(strlen(device)+1);
49 if (!str)
50 return NULL;
51 strcpy(str, device);
52 cp = str;
53
54 /* Skip over /dev/; if it's not present, give up. */
55 if (strncmp(cp, "/dev/", 5) != 0)
56 goto errout;
57 cp += 5;
58
59 /* Skip over /dev/dsk/... */
60 if (strncmp(cp, "dsk/", 4) == 0)
61 cp += 4;
62
63 /*
64 * For md devices, we treat them all as if they were all
65 * on one disk, since we don't know how to parallelize them.
66 */
67 if (cp[0] == 'm' && cp[1] == 'd') {
68 *(cp+2) = 0;
69 return str;
70 }
71
72 /* Handle DAC 960 devices */
73 if (strncmp(cp, "rd/", 3) == 0) {
74 cp += 3;
75 if (cp[0] != 'c' || cp[2] != 'd' ||
76 !isdigit(cp[1]) || !isdigit(cp[3]))
77 goto errout;
78 *(cp+4) = 0;
79 return str;
80 }
81
82 /* Now let's handle /dev/hd* and /dev/sd* devices.... */
83 if ((cp[0] == 'h' || cp[0] == 's') && (cp[1] == 'd')) {
84 cp += 2;
85 /* If there's a single number after /dev/hd, skip it */
86 if (isdigit(*cp))
87 cp++;
88 /* What follows must be an alpha char, or give up */
89 if (!isalpha(*cp))
90 goto errout;
91 *(cp + 1) = 0;
92 return str;
93 }
94
95 /* Now let's handle devfs (ugh) names */
96 len = 0;
97 if (strncmp(cp, "ide/", 4) == 0)
98 len = 4;
99 if (strncmp(cp, "scsi/", 5) == 0)
100 len = 5;
101 if (len) {
102 cp += len;
103 /*
104 * Now we proceed down the expected devfs hierarchy.
105 * i.e., .../host1/bus2/target3/lun4/...
106 * If we don't find the expected token, followed by
107 * some number of digits at each level, abort.
108 */
109 for (hier = devfs_hier; *hier; hier++) {
110 len = strlen(*hier);
111 if (strncmp(cp, *hier, len) != 0)
112 goto errout;
113 cp += len;
114 while (*cp != '/' && *cp != 0) {
115 if (!isdigit(*cp))
116 goto errout;
117 cp++;
118 }
119 cp++;
120 }
121 *(cp - 1) = 0;
122 return str;
123 }
124
125 /* Now handle devfs /dev/disc or /dev/disk names */
126 disk = 0;
127 if (strncmp(cp, "discs/", 6) == 0)
128 disk = "disc";
129 else if (strncmp(cp, "disks/", 6) == 0)
130 disk = "disk";
131 if (disk) {
132 cp += 6;
133 if (strncmp(cp, disk, 4) != 0)
134 goto errout;
135 cp += 4;
136 while (*cp != '/' && *cp != 0) {
137 if (!isdigit(*cp))
138 goto errout;
139 cp++;
140 }
141 *cp = 0;
142 return str;
143 }
144
145 errout:
146 free(str);
147 return NULL;
148 }
149
150 #ifdef DEBUG
main(int argc,char ** argv)151 int main(int argc, char** argv)
152 {
153 const char *base;
154 char buf[256], *cp;
155
156 while (1) {
157 if (fgets(buf, sizeof(buf), stdin) == NULL)
158 break;
159 cp = strchr(buf, '\n');
160 if (cp)
161 *cp = 0;
162 cp = strchr(buf, '\t');
163 if (cp)
164 *cp = 0;
165 base = base_device(buf);
166 printf("%s\t%s\n", buf, base ? base : "NONE");
167 }
168 exit(0);
169 }
170 #endif
171