200 lines
6.3 KiB
C
200 lines
6.3 KiB
C
/* IBM device driver utility functions. Author: Kees J. Bot
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* 7 Dec 1995
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* Entry point:
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* partition: partition a disk to the partition table(s) on it.
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*/
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#include "driver.h"
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#include "drvlib.h"
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#include <unistd.h>
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/* Extended partition? */
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#define ext_part(s) ((s) == 0x05 || (s) == 0x0F)
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FORWARD _PROTOTYPE( void extpartition, (struct driver *dp, int extdev,
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unsigned long extbase) );
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FORWARD _PROTOTYPE( int get_part_table, (struct driver *dp, int device,
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unsigned long offset, struct part_entry *table));
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FORWARD _PROTOTYPE( void sort, (struct part_entry *table) );
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#ifndef CD_SECTOR_SIZE
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#define CD_SECTOR_SIZE 2048
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#endif
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/*============================================================================*
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* partition *
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*============================================================================*/
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PUBLIC void partition(dp, device, style, atapi)
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struct driver *dp; /* device dependent entry points */
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int device; /* device to partition */
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int style; /* partitioning style: floppy, primary, sub. */
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int atapi; /* atapi device */
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{
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/* This routine is called on first open to initialize the partition tables
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* of a device. It makes sure that each partition falls safely within the
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* device's limits. Depending on the partition style we are either making
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* floppy partitions, primary partitions or subpartitions. Only primary
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* partitions are sorted, because they are shared with other operating
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* systems that expect this.
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*/
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struct part_entry table[NR_PARTITIONS], *pe;
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int disk, par;
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struct device *dv;
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unsigned long base, limit, part_limit;
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/* Get the geometry of the device to partition */
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if ((dv = (*dp->dr_prepare)(device)) == NIL_DEV
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|| cmp64u(dv->dv_size, 0) == 0) return;
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base = div64u(dv->dv_base, SECTOR_SIZE);
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limit = base + div64u(dv->dv_size, SECTOR_SIZE);
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/* Read the partition table for the device. */
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if(!get_part_table(dp, device, 0L, table)) {
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return;
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}
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/* Compute the device number of the first partition. */
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switch (style) {
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case P_FLOPPY:
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device += MINOR_fd0p0;
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break;
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case P_PRIMARY:
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sort(table); /* sort a primary partition table */
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device += 1;
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break;
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case P_SUB:
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disk = device / DEV_PER_DRIVE;
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par = device % DEV_PER_DRIVE - 1;
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device = MINOR_d0p0s0 + (disk * NR_PARTITIONS + par) * NR_PARTITIONS;
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}
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/* Find an array of devices. */
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if ((dv = (*dp->dr_prepare)(device)) == NIL_DEV) return;
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/* Set the geometry of the partitions from the partition table. */
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for (par = 0; par < NR_PARTITIONS; par++, dv++) {
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/* Shrink the partition to fit within the device. */
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pe = &table[par];
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part_limit = pe->lowsec + pe->size;
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if (part_limit < pe->lowsec) part_limit = limit;
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if (part_limit > limit) part_limit = limit;
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if (pe->lowsec < base) pe->lowsec = base;
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if (part_limit < pe->lowsec) part_limit = pe->lowsec;
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dv->dv_base = mul64u(pe->lowsec, SECTOR_SIZE);
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dv->dv_size = mul64u(part_limit - pe->lowsec, SECTOR_SIZE);
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if (style == P_PRIMARY) {
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/* Each Minix primary partition can be subpartitioned. */
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if (pe->sysind == MINIX_PART)
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partition(dp, device + par, P_SUB, atapi);
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/* An extended partition has logical partitions. */
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if (ext_part(pe->sysind))
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extpartition(dp, device + par, pe->lowsec);
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}
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}
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}
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/*============================================================================*
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* extpartition *
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*============================================================================*/
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PRIVATE void extpartition(dp, extdev, extbase)
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struct driver *dp; /* device dependent entry points */
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int extdev; /* extended partition to scan */
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unsigned long extbase; /* sector offset of the base extended partition */
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{
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/* Extended partitions cannot be ignored alas, because people like to move
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* files to and from DOS partitions. Avoid reading this code, it's no fun.
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*/
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struct part_entry table[NR_PARTITIONS], *pe;
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int subdev, disk, par;
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struct device *dv;
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unsigned long offset, nextoffset;
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disk = extdev / DEV_PER_DRIVE;
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par = extdev % DEV_PER_DRIVE - 1;
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subdev = MINOR_d0p0s0 + (disk * NR_PARTITIONS + par) * NR_PARTITIONS;
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offset = 0;
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do {
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if (!get_part_table(dp, extdev, offset, table)) return;
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sort(table);
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/* The table should contain one logical partition and optionally
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* another extended partition. (It's a linked list.)
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*/
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nextoffset = 0;
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for (par = 0; par < NR_PARTITIONS; par++) {
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pe = &table[par];
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if (ext_part(pe->sysind)) {
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nextoffset = pe->lowsec;
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} else
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if (pe->sysind != NO_PART) {
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if ((dv = (*dp->dr_prepare)(subdev)) == NIL_DEV) return;
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dv->dv_base = mul64u(extbase + offset + pe->lowsec,
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SECTOR_SIZE);
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dv->dv_size = mul64u(pe->size, SECTOR_SIZE);
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/* Out of devices? */
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if (++subdev % NR_PARTITIONS == 0) return;
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}
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}
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} while ((offset = nextoffset) != 0);
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}
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/*============================================================================*
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* get_part_table *
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*============================================================================*/
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PRIVATE int get_part_table(dp, device, offset, table)
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struct driver *dp;
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int device;
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unsigned long offset; /* sector offset to the table */
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struct part_entry *table; /* four entries */
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{
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/* Read the partition table for the device, return true iff there were no
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* errors.
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*/
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iovec_t iovec1;
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u64_t position;
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static unsigned char partbuf[CD_SECTOR_SIZE];
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position = mul64u(offset, SECTOR_SIZE);
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iovec1.iov_addr = (vir_bytes) partbuf;
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iovec1.iov_size = CD_SECTOR_SIZE;
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if ((*dp->dr_prepare)(device) != NIL_DEV) {
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(void) (*dp->dr_transfer)(SELF, DEV_GATHER_S, position, &iovec1, 1, 0);
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}
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if (iovec1.iov_size != 0) {
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return 0;
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}
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if (partbuf[510] != 0x55 || partbuf[511] != 0xAA) {
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/* Invalid partition table. */
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return 0;
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}
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memcpy(table, (partbuf + PART_TABLE_OFF), NR_PARTITIONS * sizeof(table[0]));
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return 1;
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}
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/*===========================================================================*
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* sort *
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*===========================================================================*/
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PRIVATE void sort(table)
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struct part_entry *table;
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{
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/* Sort a partition table. */
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struct part_entry *pe, tmp;
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int n = NR_PARTITIONS;
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do {
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for (pe = table; pe < table + NR_PARTITIONS-1; pe++) {
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if (pe[0].sysind == NO_PART
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|| (pe[0].lowsec > pe[1].lowsec
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&& pe[1].sysind != NO_PART)) {
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tmp = pe[0]; pe[0] = pe[1]; pe[1] = tmp;
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}
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}
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} while (--n > 0);
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}
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