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1275 |
phoenix |
/*
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* linux/fs/hfs/part_tbl.c
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*
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* Copyright (C) 1996-1997 Paul H. Hargrove
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* This file may be distributed under the terms of the GNU General Public License.
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*
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* Original code to handle the new style Mac partition table based on
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* a patch contributed by Holger Schemel (aeglos@valinor.owl.de).
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*
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* "XXX" in a comment is a note to myself to consider changing something.
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*
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* In function preconditions the term "valid" applied to a pointer to
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* a structure means that the pointer is non-NULL and the structure it
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* points to has all fields initialized to consistent values.
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*
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* The code in this file initializes some structures which contain
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* pointers by calling memset(&foo, 0, sizeof(foo)).
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* This produces the desired behavior only due to the non-ANSI
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* assumption that the machine representation of NULL is all zeros.
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*/
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#include "hfs.h"
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/*================ File-local data types ================*/
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/*
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* The Macintosh Driver Descriptor Block
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*
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* On partitioned Macintosh media this is block 0.
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* We really only need the "magic number" to check for partitioned media.
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*/
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struct hfs_drvr_desc {
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hfs_word_t ddSig; /* The signature word */
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/* a bunch more stuff we don't need */
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};
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/*
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* The new style Mac partition map
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*
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* For each partition on the media there is a physical block (512-byte
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* block) containing one of these structures. These blocks are
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* contiguous starting at block 1.
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*/
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struct new_pmap {
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hfs_word_t pmSig; /* Signature bytes to verify
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that this is a partition
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map block */
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hfs_word_t reSigPad; /* padding */
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hfs_lword_t pmMapBlkCnt; /* (At least in block 1) this
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is the number of partition
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map blocks */
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hfs_lword_t pmPyPartStart; /* The physical block number
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of the first block in this
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partition */
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hfs_lword_t pmPartBlkCnt; /* The number of physical
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blocks in this partition */
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hfs_byte_t pmPartName[32]; /* (null terminated?) string
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giving the name of this
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partition */
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hfs_byte_t pmPartType[32]; /* (null terminated?) string
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giving the type of this
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partition */
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/* a bunch more stuff we don't need */
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};
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/*
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* The old style Mac partition map
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*
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* The partition map consists for a 2-byte signature followed by an
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* array of these structures. The map is terminated with an all-zero
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* one of these.
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*/
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struct old_pmap {
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hfs_word_t pdSig; /* Signature bytes */
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struct old_pmap_entry {
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hfs_lword_t pdStart;
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hfs_lword_t pdSize;
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hfs_lword_t pdFSID;
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} pdEntry[42];
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} __attribute__((packed));
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/*================ File-local functions ================*/
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/*
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* parse_new_part_table()
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*
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* Parse a new style partition map looking for the
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* start and length of the 'part'th HFS partition.
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*/
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static int parse_new_part_table(hfs_sysmdb sys_mdb, hfs_buffer buf,
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int part, hfs_s32 *size, hfs_s32 *start)
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{
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struct new_pmap *pm = (struct new_pmap *)hfs_buffer_data(buf);
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hfs_u32 pmap_entries = hfs_get_hl(pm->pmMapBlkCnt);
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int hfs_part = 0;
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int entry;
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for (entry = 0; (entry < pmap_entries) && !(*start); ++entry) {
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if (entry) {
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/* read the next partition map entry */
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buf = hfs_buffer_get(sys_mdb, HFS_PMAP_BLK + entry, 1);
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if (!hfs_buffer_ok(buf)) {
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hfs_warn("hfs_fs: unable to "
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"read partition map.\n");
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goto bail;
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}
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pm = (struct new_pmap *)hfs_buffer_data(buf);
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if (hfs_get_ns(pm->pmSig) !=
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htons(HFS_NEW_PMAP_MAGIC)) {
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hfs_warn("hfs_fs: invalid "
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"entry in partition map\n");
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hfs_buffer_put(buf);
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goto bail;
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}
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}
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/* look for an HFS partition */
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if (!memcmp(pm->pmPartType,"Apple_HFS",9) &&
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((hfs_part++) == part)) {
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/* Found it! */
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*start = hfs_get_hl(pm->pmPyPartStart);
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*size = hfs_get_hl(pm->pmPartBlkCnt);
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}
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hfs_buffer_put(buf);
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}
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return 0;
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bail:
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return 1;
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}
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/*
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* parse_old_part_table()
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*
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* Parse a old style partition map looking for the
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* start and length of the 'part'th HFS partition.
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*/
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static int parse_old_part_table(hfs_sysmdb sys_mdb, hfs_buffer buf,
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int part, hfs_s32 *size, hfs_s32 *start)
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{
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struct old_pmap *pm = (struct old_pmap *)hfs_buffer_data(buf);
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struct old_pmap_entry *p = &pm->pdEntry[0];
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int hfs_part = 0;
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while ((p->pdStart || p->pdSize || p->pdFSID) && !(*start)) {
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/* look for an HFS partition */
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if ((hfs_get_nl(p->pdFSID) == htonl(0x54465331)/*"TFS1"*/) &&
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((hfs_part++) == part)) {
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/* Found it! */
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*start = hfs_get_hl(p->pdStart);
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*size = hfs_get_hl(p->pdSize);
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}
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++p;
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}
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hfs_buffer_put(buf);
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return 0;
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}
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/*================ Global functions ================*/
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/*
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* hfs_part_find()
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*
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* Parse the partition map looking for the
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* start and length of the 'part'th HFS partition.
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*/
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int hfs_part_find(hfs_sysmdb sys_mdb, int part, int silent,
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hfs_s32 *size, hfs_s32 *start)
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{
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hfs_buffer buf;
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hfs_u16 sig;
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int dd_found = 0;
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int retval = 1;
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/* Read block 0 to see if this media is partitioned */
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buf = hfs_buffer_get(sys_mdb, HFS_DD_BLK, 1);
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if (!hfs_buffer_ok(buf)) {
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hfs_warn("hfs_fs: Unable to read block 0.\n");
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goto done;
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}
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sig = hfs_get_ns(((struct hfs_drvr_desc *)hfs_buffer_data(buf))->ddSig);
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hfs_buffer_put(buf);
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if (sig == htons(HFS_DRVR_DESC_MAGIC)) {
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/* We are definitely on partitioned media. */
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dd_found = 1;
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}
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buf = hfs_buffer_get(sys_mdb, HFS_PMAP_BLK, 1);
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if (!hfs_buffer_ok(buf)) {
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hfs_warn("hfs_fs: Unable to read block 1.\n");
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goto done;
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}
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*size = *start = 0;
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switch (hfs_get_ns(hfs_buffer_data(buf))) {
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case __constant_htons(HFS_OLD_PMAP_MAGIC):
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retval = parse_old_part_table(sys_mdb, buf, part, size, start);
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break;
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case __constant_htons(HFS_NEW_PMAP_MAGIC):
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retval = parse_new_part_table(sys_mdb, buf, part, size, start);
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break;
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default:
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if (dd_found) {
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/* The media claimed to have a partition map */
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if (!silent) {
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hfs_warn("hfs_fs: This disk has an "
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"unrecognized partition map type.\n");
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}
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} else {
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/* Conclude that the media is not partitioned */
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retval = 0;
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}
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goto done;
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}
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if (!retval) {
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if (*start == 0) {
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if (part) {
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hfs_warn("hfs_fs: unable to locate "
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"HFS partition number %d.\n", part);
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} else {
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hfs_warn("hfs_fs: unable to locate any "
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"HFS partitions.\n");
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}
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retval = 1;
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} else if (*size < 0) {
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hfs_warn("hfs_fs: Partition size > 1 Terabyte.\n");
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retval = 1;
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} else if (*start < 0) {
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hfs_warn("hfs_fs: Partition begins beyond 1 "
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"Terabyte.\n");
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retval = 1;
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}
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| 241 |
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}
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done:
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return retval;
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| 244 |
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}
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