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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 | /* * linux/fs/hfs/part_tbl.c * * Copyright (C) 1996-1997 Paul H. Hargrove * This file may be distributed under the terms of the GNU General Public License. * * Original code to handle the new style Mac partition table based on * a patch contributed by Holger Schemel (aeglos@valinor.owl.de). * * "XXX" in a comment is a note to myself to consider changing something. * * In function preconditions the term "valid" applied to a pointer to * a structure means that the pointer is non-NULL and the structure it * points to has all fields initialized to consistent values. * * The code in this file initializes some structures which contain * pointers by calling memset(&foo, 0, sizeof(foo)). * This produces the desired behavior only due to the non-ANSI * assumption that the machine representation of NULL is all zeros. */ #include "hfs.h" /*================ File-local data types ================*/ /* * The Macintosh Driver Descriptor Block * * On partitioned Macintosh media this is block 0. * We really only need the "magic number" to check for partitioned media. */ struct hfs_drvr_desc { hfs_word_t ddSig; /* The signature word */ /* a bunch more stuff we don't need */ }; /* * The new style Mac partition map * * For each partition on the media there is a physical block (512-byte * block) containing one of these structures. These blocks are * contiguous starting at block 1. */ struct new_pmap { hfs_word_t pmSig; /* Signature bytes to verify that this is a partition map block */ hfs_word_t reSigPad; /* padding */ hfs_lword_t pmMapBlkCnt; /* (At least in block 1) this is the number of partition map blocks */ hfs_lword_t pmPyPartStart; /* The physical block number of the first block in this partition */ hfs_lword_t pmPartBlkCnt; /* The number of physical blocks in this partition */ hfs_byte_t pmPartName[32]; /* (null terminated?) string giving the name of this partition */ hfs_byte_t pmPartType[32]; /* (null terminated?) string giving the type of this partition */ /* a bunch more stuff we don't need */ }; /* * The old style Mac partition map * * The partition map consists for a 2-byte signature followed by an * array of these structures. The map is terminated with an all-zero * one of these. */ struct old_pmap { hfs_word_t pdSig; /* Signature bytes */ struct old_pmap_entry { hfs_lword_t pdStart; hfs_lword_t pdSize; hfs_lword_t pdFSID; } pdEntry[42]; } __attribute__((packed)); /*================ File-local functions ================*/ /* * parse_new_part_table() * * Parse a new style partition map looking for the * start and length of the 'part'th HFS partition. */ static int parse_new_part_table(hfs_sysmdb sys_mdb, hfs_buffer buf, int part, hfs_s32 *size, hfs_s32 *start) { struct new_pmap *pm = (struct new_pmap *)hfs_buffer_data(buf); hfs_u32 pmap_entries = hfs_get_hl(pm->pmMapBlkCnt); int hfs_part = 0; int entry; for (entry = 0; (entry < pmap_entries) && !(*start); ++entry) { if (entry) { /* read the next partition map entry */ buf = hfs_buffer_get(sys_mdb, HFS_PMAP_BLK + entry, 1); if (!hfs_buffer_ok(buf)) { hfs_warn("hfs_fs: unable to " "read partition map.\n"); goto bail; } pm = (struct new_pmap *)hfs_buffer_data(buf); if (hfs_get_ns(pm->pmSig) != htons(HFS_NEW_PMAP_MAGIC)) { hfs_warn("hfs_fs: invalid " "entry in partition map\n"); hfs_buffer_put(buf); goto bail; } } /* look for an HFS partition */ if (!memcmp(pm->pmPartType,"Apple_HFS",9) && ((hfs_part++) == part)) { /* Found it! */ *start = hfs_get_hl(pm->pmPyPartStart); *size = hfs_get_hl(pm->pmPartBlkCnt); } hfs_buffer_put(buf); } return 0; bail: return 1; } /* * parse_old_part_table() * * Parse a old style partition map looking for the * start and length of the 'part'th HFS partition. */ static int parse_old_part_table(hfs_sysmdb sys_mdb, hfs_buffer buf, int part, hfs_s32 *size, hfs_s32 *start) { struct old_pmap *pm = (struct old_pmap *)hfs_buffer_data(buf); struct old_pmap_entry *p = &pm->pdEntry[0]; int hfs_part = 0; while ((p->pdStart || p->pdSize || p->pdFSID) && !(*start)) { /* look for an HFS partition */ if ((hfs_get_nl(p->pdFSID) == htonl(0x54465331)/*"TFS1"*/) && ((hfs_part++) == part)) { /* Found it! */ *start = hfs_get_hl(p->pdStart); *size = hfs_get_hl(p->pdSize); } ++p; } hfs_buffer_put(buf); return 0; } /*================ Global functions ================*/ /* * hfs_part_find() * * Parse the partition map looking for the * start and length of the 'part'th HFS partition. */ int hfs_part_find(hfs_sysmdb sys_mdb, int part, int silent, hfs_s32 *size, hfs_s32 *start) { hfs_buffer buf; hfs_u16 sig; int dd_found = 0; int retval = 1; /* Read block 0 to see if this media is partitioned */ buf = hfs_buffer_get(sys_mdb, HFS_DD_BLK, 1); if (!hfs_buffer_ok(buf)) { hfs_warn("hfs_fs: Unable to read block 0.\n"); goto done; } sig = hfs_get_ns(((struct hfs_drvr_desc *)hfs_buffer_data(buf))->ddSig); hfs_buffer_put(buf); if (sig == htons(HFS_DRVR_DESC_MAGIC)) { /* We are definitely on partitioned media. */ dd_found = 1; } buf = hfs_buffer_get(sys_mdb, HFS_PMAP_BLK, 1); if (!hfs_buffer_ok(buf)) { hfs_warn("hfs_fs: Unable to read block 1.\n"); goto done; } *size = *start = 0; switch (hfs_get_ns(hfs_buffer_data(buf))) { case __constant_htons(HFS_OLD_PMAP_MAGIC): retval = parse_old_part_table(sys_mdb, buf, part, size, start); break; case __constant_htons(HFS_NEW_PMAP_MAGIC): retval = parse_new_part_table(sys_mdb, buf, part, size, start); break; default: if (dd_found) { /* The media claimed to have a partition map */ if (!silent) { hfs_warn("hfs_fs: This disk has an " "unrecognized partition map type.\n"); } } else { /* Conclude that the media is not partitioned */ retval = 0; } goto done; } if (!retval) { if (*start == 0) { if (part) { hfs_warn("hfs_fs: unable to locate " "HFS partition number %d.\n", part); } else { hfs_warn("hfs_fs: unable to locate any " "HFS partitions.\n"); } retval = 1; } else if (*size < 0) { hfs_warn("hfs_fs: Partition size > 1 Terabyte.\n"); retval = 1; } else if (*start < 0) { hfs_warn("hfs_fs: Partition begins beyond 1 " "Terabyte.\n"); retval = 1; } } done: return retval; } |