1 /* ----------------------------------------------------------------------- *
2 *
3 * Copyright 2003-2009 H. Peter Anvin - All Rights Reserved
4 * Copyright 2009-2010 Intel Corporation; author: H. Peter Anvin
5 * Copyright 2010 Shao Miller
6 * Copyright 2010-2012 Michal Soltys
7 *
8 * Permission is hereby granted, free of charge, to any person
9 * obtaining a copy of this software and associated documentation
10 * files (the "Software"), to deal in the Software without
11 * restriction, including without limitation the rights to use,
12 * copy, modify, merge, publish, distribute, sublicense, and/or
13 * sell copies of the Software, and to permit persons to whom
14 * the Software is furnished to do so, subject to the following
15 * conditions:
16 *
17 * The above copyright notice and this permission notice shall
18 * be included in all copies or substantial portions of the Software.
19 *
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
21 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
22 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
23 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
24 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
25 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
26 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
27 * OTHER DEALINGS IN THE SOFTWARE.
28 *
29 * ----------------------------------------------------------------------- */
30
31 #include <com32.h>
32 #include <fcntl.h>
33 #include <stdint.h>
34 #include <stdio.h>
35 #include <errno.h>
36 #include <unistd.h>
37 #include <string.h>
38 #include <fs.h>
39 #include <syslinux/disk.h>
40 #include <syslinux/pmapi.h>
41 #include "utility.h"
42
43 static const char *bpbtypes[] = {
44 [0] = "unknown",
45 [1] = "2.0",
46 [2] = "3.0",
47 [3] = "3.2",
48 [4] = "3.4",
49 [5] = "4.0",
50 [6] = "8.0 (NT+)",
51 [7] = "7.0",
52 [8] = "exFAT",
53 };
54
wait_key(void)55 void wait_key(void)
56 {
57 int cnt;
58 char junk;
59
60 /* drain */
61 do {
62 errno = 0;
63 cnt = read(0, &junk, 1);
64 } while (cnt > 0 || (cnt < 0 && errno == EAGAIN));
65
66 /* wait */
67 do {
68 errno = 0;
69 cnt = read(0, &junk, 1);
70 } while (!cnt || (cnt < 0 && errno == EAGAIN));
71 }
72
guid_is0(const struct guid * guid)73 int guid_is0(const struct guid *guid)
74 {
75 return
76 !(guid->data1 ||
77 guid->data2 ||
78 guid->data3 ||
79 guid->data4);
80 }
81
82 /*
83 * mode explanation:
84 *
85 * cnul - "strict" mode, never returning higher value than obtained from cbios
86 * cadd - if the disk is larger than reported geometry /and/ if the geometry has
87 * less cylinders than 1024 - it means that the total size is somewhere
88 * between cs and cs+1; in this particular case, we bump the cs to be able
89 * to return matching chs triplet
90 * cmax - assume we can use any cylinder value
91 *
92 * by default cadd seems most reasonable, giving consistent results with e.g.
93 * sfdisk's behavior
94 */
lba2chs(disk_chs * dst,const struct disk_info * di,uint64_t lba,int mode)95 void lba2chs(disk_chs *dst, const struct disk_info *di, uint64_t lba, int mode)
96 {
97 uint32_t c, h, s, t;
98 uint32_t cs, hs, ss;
99
100 /*
101 * Not much reason here, but if we have no valid CHS geometry, we assume
102 * "typical" ones to have something to return.
103 */
104 if (di->cbios) {
105 cs = di->cyl;
106 hs = di->head;
107 ss = di->spt;
108 if (mode == L2C_CADD) {
109 if (cs < 1024 && di->lbacnt > cs*hs*ss)
110 cs++;
111 } else if (mode == L2C_CMAX)
112 cs = 1024;
113 } else {
114 if (di->disk & 0x80) {
115 cs = 1024;
116 hs = 255;
117 ss = 63;
118 } else {
119 cs = 80;
120 hs = 2;
121 ss = 18;
122 }
123 }
124
125 if (lba >= cs*hs*ss) {
126 s = ss;
127 h = hs - 1;
128 c = cs - 1;
129 } else {
130 s = (lba % ss) + 1;
131 t = lba / ss;
132 h = t % hs;
133 c = t / hs;
134 }
135
136 (*dst)[0] = h;
137 (*dst)[1] = s | ((c & 0x300) >> 2);
138 (*dst)[2] = c;
139 }
140
get_file_lba(const char * filename)141 uint32_t get_file_lba(const char *filename)
142 {
143 struct com32_filedata fd;
144 uint32_t lba = 0;
145 int size = 65536;
146 char *buf;
147
148 buf = lmalloc(size);
149 if (!buf)
150 return 0;
151
152 /* Put the filename in the bounce buffer */
153 strlcpy(buf, filename, size);
154
155 if (open_file(buf, O_RDONLY, &fd) <= 0) {
156 goto fail; /* Filename not found */
157 }
158
159 /* Since the first member is the LBA, we simply cast */
160 lba = *((uint32_t *) MK_PTR(0, fd.handle));
161
162 /* Call comapi_close() to free the structure */
163 close_file(fd.handle);
164
165 fail:
166 lfree(buf);
167 return lba;
168 }
169
170 /* drive offset detection */
drvoff_detect(int type)171 int drvoff_detect(int type)
172 {
173 if (bpbV40 <= type && type <= bpbVNT) {
174 return 0x24;
175 } else if (type == bpbV70) {
176 return 0x40;
177 } else if (type == bpbEXF) {
178 return 0x6F;
179 }
180
181 return -1;
182 }
183
184 /*
185 * heuristics could certainly be improved
186 */
bpb_detect(const uint8_t * sec,const char * tag)187 int bpb_detect(const uint8_t *sec, const char *tag)
188 {
189 int a, b, c, jmp = -1, rev = 0;
190
191 /* exFAT mess first (media descriptor is 0 here) */
192 if (!memcmp(sec + 0x03, "EXFAT ", 8)) {
193 rev = bpbEXF;
194 goto out;
195 }
196
197 /* media descriptor check */
198 if ((sec[0x15] & 0xF0) != 0xF0)
199 goto out;
200
201 if (sec[0] == 0xEB) /* jump short */
202 jmp = 2 + *(int8_t *)(sec + 1);
203 else if (sec[0] == 0xE9) /* jump near */
204 jmp = 3 + *(int16_t *)(sec + 1);
205
206 if (jmp < 0) /* no boot code at all ? */
207 goto nocode;
208
209 /* sanity */
210 if (jmp < 0x18 || jmp > 0x1F0)
211 goto out;
212
213 /* detect by jump */
214 if (jmp >= 0x18 && jmp < 0x1E)
215 rev = bpbV20;
216 else if (jmp >= 0x1E && jmp < 0x20)
217 rev = bpbV30;
218 else if (jmp >= 0x20 && jmp < 0x24)
219 rev = bpbV32;
220 else if (jmp >= 0x24 && jmp < 0x46)
221 rev = bpbV34;
222
223 /* TODO: some better V2 - V3.4 checks ? */
224
225 if (rev)
226 goto out;
227 /*
228 * BPB info:
229 * 2.0 == 0x0B - 0x17
230 * 3.0 == 2.0 + 0x18 - 0x1D
231 * 3.2 == 3.0 + 0x1E - 0x1F
232 * 3.4 ==!2.0 + 0x18 - 0x23
233 * 4.0 == 3.4 + 0x24 - 0x45
234 * NT ==~3.4 + 0x24 - 0x53
235 * 7.0 == 3.4 + 0x24 - 0x59
236 */
237
238 nocode:
239 a = memcmp(sec + 0x03, "NTFS", 4);
240 b = memcmp(sec + 0x36, "FAT", 3);
241 c = memcmp(sec + 0x52, "FAT", 3); /* ext. DOS 7+ bs */
242
243 if ((sec[0x26] & 0xFE) == 0x28 && !b) {
244 rev = bpbV40;
245 } else if (sec[0x26] == 0x80 && !a) {
246 rev = bpbVNT;
247 } else if ((sec[0x42] & 0xFE) == 0x28 && !c) {
248 rev = bpbV70;
249 }
250
251 out:
252 printf("BPB detection (%s): %s\n", tag, bpbtypes[rev]);
253 return rev;
254 }
255
256 /* vim: set ts=8 sts=4 sw=4 noet: */
257