source: branches/minix3-book/drivers/libdriver/drvlib.c@ 15

Last change on this file since 15 was 4, checked in by Mattia Monga, 14 years ago

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1/* IBM device driver utility functions. Author: Kees J. Bot
2 * 7 Dec 1995
3 * Entry point:
4 * partition: partition a disk to the partition table(s) on it.
5 */
6
7#include "driver.h"
8#include "drvlib.h"
9#include <unistd.h>
10
11/* Extended partition? */
12#define ext_part(s) ((s) == 0x05 || (s) == 0x0F)
13
14FORWARD _PROTOTYPE( void extpartition, (struct driver *dp, int extdev,
15 unsigned long extbase) );
16FORWARD _PROTOTYPE( int get_part_table, (struct driver *dp, int device,
17 unsigned long offset, struct part_entry *table));
18FORWARD _PROTOTYPE( void sort, (struct part_entry *table) );
19
20#ifndef CD_SECTOR_SIZE
21#define CD_SECTOR_SIZE 2048
22#endif
23
24/*============================================================================*
25 * partition *
26 *============================================================================*/
27PUBLIC void partition(dp, device, style, atapi)
28struct driver *dp; /* device dependent entry points */
29int device; /* device to partition */
30int style; /* partitioning style: floppy, primary, sub. */
31int atapi; /* atapi device */
32{
33/* This routine is called on first open to initialize the partition tables
34 * of a device. It makes sure that each partition falls safely within the
35 * device's limits. Depending on the partition style we are either making
36 * floppy partitions, primary partitions or subpartitions. Only primary
37 * partitions are sorted, because they are shared with other operating
38 * systems that expect this.
39 */
40 struct part_entry table[NR_PARTITIONS], *pe;
41 int disk, par;
42 struct device *dv;
43 unsigned long base, limit, part_limit;
44
45 /* Get the geometry of the device to partition */
46 if ((dv = (*dp->dr_prepare)(device)) == NIL_DEV
47 || cmp64u(dv->dv_size, 0) == 0) return;
48 base = div64u(dv->dv_base, SECTOR_SIZE);
49 limit = base + div64u(dv->dv_size, SECTOR_SIZE);
50
51 /* Read the partition table for the device. */
52 if(!get_part_table(dp, device, 0L, table)) {
53 return;
54 }
55
56 /* Compute the device number of the first partition. */
57 switch (style) {
58 case P_FLOPPY:
59 device += MINOR_fd0p0;
60 break;
61 case P_PRIMARY:
62 sort(table); /* sort a primary partition table */
63 device += 1;
64 break;
65 case P_SUB:
66 disk = device / DEV_PER_DRIVE;
67 par = device % DEV_PER_DRIVE - 1;
68 device = MINOR_d0p0s0 + (disk * NR_PARTITIONS + par) * NR_PARTITIONS;
69 }
70
71 /* Find an array of devices. */
72 if ((dv = (*dp->dr_prepare)(device)) == NIL_DEV) return;
73
74 /* Set the geometry of the partitions from the partition table. */
75 for (par = 0; par < NR_PARTITIONS; par++, dv++) {
76 /* Shrink the partition to fit within the device. */
77 pe = &table[par];
78 part_limit = pe->lowsec + pe->size;
79 if (part_limit < pe->lowsec) part_limit = limit;
80 if (part_limit > limit) part_limit = limit;
81 if (pe->lowsec < base) pe->lowsec = base;
82 if (part_limit < pe->lowsec) part_limit = pe->lowsec;
83
84 dv->dv_base = mul64u(pe->lowsec, SECTOR_SIZE);
85 dv->dv_size = mul64u(part_limit - pe->lowsec, SECTOR_SIZE);
86
87 if (style == P_PRIMARY) {
88 /* Each Minix primary partition can be subpartitioned. */
89 if (pe->sysind == MINIX_PART)
90 partition(dp, device + par, P_SUB, atapi);
91
92 /* An extended partition has logical partitions. */
93 if (ext_part(pe->sysind))
94 extpartition(dp, device + par, pe->lowsec);
95 }
96 }
97}
98
99/*============================================================================*
100 * extpartition *
101 *============================================================================*/
102PRIVATE void extpartition(dp, extdev, extbase)
103struct driver *dp; /* device dependent entry points */
104int extdev; /* extended partition to scan */
105unsigned long extbase; /* sector offset of the base extended partition */
106{
107/* Extended partitions cannot be ignored alas, because people like to move
108 * files to and from DOS partitions. Avoid reading this code, it's no fun.
109 */
110 struct part_entry table[NR_PARTITIONS], *pe;
111 int subdev, disk, par;
112 struct device *dv;
113 unsigned long offset, nextoffset;
114
115 disk = extdev / DEV_PER_DRIVE;
116 par = extdev % DEV_PER_DRIVE - 1;
117 subdev = MINOR_d0p0s0 + (disk * NR_PARTITIONS + par) * NR_PARTITIONS;
118
119 offset = 0;
120 do {
121 if (!get_part_table(dp, extdev, offset, table)) return;
122 sort(table);
123
124 /* The table should contain one logical partition and optionally
125 * another extended partition. (It's a linked list.)
126 */
127 nextoffset = 0;
128 for (par = 0; par < NR_PARTITIONS; par++) {
129 pe = &table[par];
130 if (ext_part(pe->sysind)) {
131 nextoffset = pe->lowsec;
132 } else
133 if (pe->sysind != NO_PART) {
134 if ((dv = (*dp->dr_prepare)(subdev)) == NIL_DEV) return;
135
136 dv->dv_base = mul64u(extbase + offset + pe->lowsec,
137 SECTOR_SIZE);
138 dv->dv_size = mul64u(pe->size, SECTOR_SIZE);
139
140 /* Out of devices? */
141 if (++subdev % NR_PARTITIONS == 0) return;
142 }
143 }
144 } while ((offset = nextoffset) != 0);
145}
146
147/*============================================================================*
148 * get_part_table *
149 *============================================================================*/
150PRIVATE int get_part_table(dp, device, offset, table)
151struct driver *dp;
152int device;
153unsigned long offset; /* sector offset to the table */
154struct part_entry *table; /* four entries */
155{
156/* Read the partition table for the device, return true iff there were no
157 * errors.
158 */
159 iovec_t iovec1;
160 off_t position;
161 static unsigned char partbuf[CD_SECTOR_SIZE];
162
163 position = offset << SECTOR_SHIFT;
164 iovec1.iov_addr = (vir_bytes) partbuf;
165 iovec1.iov_size = CD_SECTOR_SIZE;
166 if ((*dp->dr_prepare)(device) != NIL_DEV) {
167 (void) (*dp->dr_transfer)(SELF, DEV_GATHER, position, &iovec1, 1);
168 }
169 if (iovec1.iov_size != 0) {
170 return 0;
171 }
172 if (partbuf[510] != 0x55 || partbuf[511] != 0xAA) {
173 /* Invalid partition table. */
174 return 0;
175 }
176 memcpy(table, (partbuf + PART_TABLE_OFF), NR_PARTITIONS * sizeof(table[0]));
177 return 1;
178}
179
180/*===========================================================================*
181 * sort *
182 *===========================================================================*/
183PRIVATE void sort(table)
184struct part_entry *table;
185{
186/* Sort a partition table. */
187 struct part_entry *pe, tmp;
188 int n = NR_PARTITIONS;
189
190 do {
191 for (pe = table; pe < table + NR_PARTITIONS-1; pe++) {
192 if (pe[0].sysind == NO_PART
193 || (pe[0].lowsec > pe[1].lowsec
194 && pe[1].sysind != NO_PART)) {
195 tmp = pe[0]; pe[0] = pe[1]; pe[1] = tmp;
196 }
197 }
198 } while (--n > 0);
199}
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