2 * Copyright (c) 2017 Conrad Meyer <cem@FreeBSD.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #include <sys/param.h>
28 #include <sys/endian.h>
43 * https://docs.microsoft.com/en-us/windows/win32/fileio/exfat-specification
50 uint64_t ev_part_offset;
51 uint64_t ev_vol_length;
52 uint32_t ev_fat_offset;
53 uint32_t ev_fat_length;
54 uint32_t ev_cluster_offset;
55 uint32_t ev_cluster_count;
56 uint32_t ev_rootdir_cluster;
57 uint32_t ev_vol_serial;
58 uint16_t ev_fs_revision;
59 uint16_t ev_vol_flags;
60 uint8_t ev_log_bytes_per_sect;
61 uint8_t ev_log_sect_per_clust;
64 uint8_t ev_percent_used;
69 #define XDE_TYPE_INUSE_MASK 0x80 /* 1=in use */
70 #define XDE_TYPE_INUSE_SHIFT 7
71 #define XDE_TYPE_CATEGORY_MASK 0x40 /* 0=primary */
72 #define XDE_TYPE_CATEGORY_SHIFT 6
73 #define XDE_TYPE_IMPORTNC_MASK 0x20 /* 0=critical */
74 #define XDE_TYPE_IMPORTNC_SHIFT 5
75 #define XDE_TYPE_CODE_MASK 0x1f
76 /* InUse=0, ..., TypeCode=0: EOD. */
77 #define XDE_TYPE_EOD 0x00
78 #define XDE_TYPE_ALLOC_BITMAP (XDE_TYPE_INUSE_MASK | 0x01)
79 #define XDE_TYPE_UPCASE_TABLE (XDE_TYPE_INUSE_MASK | 0x02)
80 #define XDE_TYPE_VOL_LABEL (XDE_TYPE_INUSE_MASK | 0x03)
81 #define XDE_TYPE_FILE (XDE_TYPE_INUSE_MASK | 0x05)
82 #define XDE_TYPE_VOL_GUID (XDE_TYPE_INUSE_MASK | XDE_TYPE_IMPORTNC_MASK)
83 #define XDE_TYPE_STREAM_EXT (XDE_TYPE_INUSE_MASK | XDE_TYPE_CATEGORY_MASK)
84 #define XDE_TYPE_FILE_NAME (XDE_TYPE_INUSE_MASK | XDE_TYPE_CATEGORY_MASK | 0x01)
85 #define XDE_TYPE_VENDOR (XDE_TYPE_INUSE_MASK | XDE_TYPE_CATEGORY_MASK | XDE_TYPE_IMPORTNC_MASK)
86 #define XDE_TYPE_VENDOR_ALLOC (XDE_TYPE_INUSE_MASK | XDE_TYPE_CATEGORY_MASK | XDE_TYPE_IMPORTNC_MASK | 0x01)
88 uint8_t xde_generic_[19];
91 * Count of "secondary" dirents following this one.
93 * A single logical entity may be composed of a
94 * sequence of several dirents, starting with a primary
95 * one; the rest are secondary dirents.
97 uint8_t xde_secondary_count_;
98 uint16_t xde_set_chksum_;
99 uint16_t xde_prim_flags_;
100 uint8_t xde_prim_generic_[14];
101 } __packed xde_primary_;
102 struct exde_secondary {
103 uint8_t xde_sec_flags_;
104 uint8_t xde_sec_generic_[18];
105 } __packed xde_secondary_;
107 uint32_t xde_first_cluster;
108 uint64_t xde_data_len;
110 #define xde_generic u.xde_generic_
111 #define xde_secondary_count u.xde_primary_.xde_secondary_count
112 #define xde_set_chksum u.xde_primary_.xde_set_chksum_
113 #define xde_prim_flags u.xde_primary_.xde_prim_flags_
114 #define xde_sec_flags u.xde_secondary_.xde_sec_flags_
115 _Static_assert(sizeof(struct exfat_dirent) == 32, "spec");
117 struct exfat_de_label {
118 uint8_t xdel_type; /* XDE_TYPE_VOL_LABEL */
119 uint8_t xdel_char_cnt; /* Length of UCS-2 label */
120 uint16_t xdel_vol_lbl[11];
121 uint8_t xdel_reserved[8];
123 _Static_assert(sizeof(struct exfat_de_label) == 32, "spec");
125 #define MAIN_BOOT_REGION_SECT 0
126 #define BACKUP_BOOT_REGION_SECT 12
128 #define SUBREGION_CHKSUM_SECT 11
130 #define FIRST_CLUSTER 2
131 #define BAD_BLOCK_SENTINEL 0xfffffff7u
132 #define END_CLUSTER_SENTINEL 0xffffffffu
135 read_sectn(FILE *fp, off_t sect, unsigned count, unsigned bytespersec)
137 return (read_buf(fp, sect * bytespersec, bytespersec * count));
141 read_sect(FILE *fp, off_t sect, unsigned bytespersec)
143 return (read_sectn(fp, sect, 1, bytespersec));
147 * Compute the byte-by-byte multi-sector checksum of the given boot region
148 * (MAIN or BACKUP), for a given bytespersec (typically 512 or 4096).
150 * Endian-safe; result is host endian.
153 exfat_compute_boot_chksum(FILE *fp, unsigned region, unsigned bytespersec,
156 unsigned char *sector;
161 for (sect = 0; sect < 11; sect++) {
162 sector = read_sect(fp, region + sect, bytespersec);
165 for (n = 0; n < bytespersec; n++) {
174 checksum = ((checksum & 1) ? 0x80000000u : 0u) +
175 (checksum >> 1) + (uint32_t)sector[n];
185 convert_label(const uint16_t *ucs2label /* LE */, unsigned ucs2len, char
186 *label_out, size_t label_sz)
189 char *label_out_orig;
193 /* Currently hardcoded in fstyp.c as 256 or so. */
194 assert(label_sz > 1);
198 * Kind of seems bogus, but the spec allows an empty label
199 * entry with the same meaning as no label.
205 warnx("exfat: Bogus volume label length: %u", ucs2len);
209 /* dstname="" means convert to the current locale. */
210 cd = iconv_open("", EXFAT_ENC);
211 if (cd == (iconv_t)-1) {
212 warn("exfat: Could not open iconv");
216 label_out_orig = label_out;
218 /* Dummy up the byte pointer and byte length iconv's API wants. */
219 label = (const void *)ucs2label;
220 srcleft = ucs2len * sizeof(*ucs2label);
222 rc = iconv(cd, __DECONST(char **, &label), &srcleft, &label_out,
224 if (rc == (size_t)-1) {
225 warn("exfat: iconv()");
226 *label_out_orig = '\0';
228 /* NUL-terminate result (iconv advances label_out). */
238 * Using the FAT table, look up the next cluster in this chain.
241 exfat_fat_next(FILE *fp, const struct exfat_vbr *ev, unsigned BPS,
244 uint32_t fat_offset_sect, clsect, clsectoff;
245 uint32_t *fatsect, nextclust;
247 fat_offset_sect = le32toh(ev->ev_fat_offset);
248 clsect = fat_offset_sect + (cluster / (BPS / sizeof(cluster)));
249 clsectoff = (cluster % (BPS / sizeof(cluster)));
251 /* XXX This is pretty wasteful without a block cache for the FAT. */
252 fatsect = read_sect(fp, clsect, BPS);
253 nextclust = le32toh(fatsect[clsectoff]);
260 exfat_find_label(FILE *fp, const struct exfat_vbr *ev, unsigned BPS,
261 char *label_out, size_t label_sz)
263 uint32_t rootdir_cluster, sects_per_clust, cluster_offset_sect;
265 struct exfat_dirent *declust, *it;
267 cluster_offset_sect = le32toh(ev->ev_cluster_offset);
268 rootdir_cluster = le32toh(ev->ev_rootdir_cluster);
269 sects_per_clust = (1u << ev->ev_log_sect_per_clust);
271 if (rootdir_cluster < FIRST_CLUSTER) {
272 warnx("%s: invalid rootdir cluster %u < %d", __func__,
273 rootdir_cluster, FIRST_CLUSTER);
278 for (; rootdir_cluster != END_CLUSTER_SENTINEL;
279 rootdir_cluster = exfat_fat_next(fp, ev, BPS, rootdir_cluster)) {
280 if (rootdir_cluster == BAD_BLOCK_SENTINEL) {
281 warnx("%s: Bogus bad block in root directory chain",
286 rootdir_sect = (rootdir_cluster - FIRST_CLUSTER) *
287 sects_per_clust + cluster_offset_sect;
288 declust = read_sectn(fp, rootdir_sect, sects_per_clust, BPS);
290 it < declust + (sects_per_clust * BPS / sizeof(*it)); it++) {
294 * Simplistic directory traversal; doesn't do any
295 * validation of "MUST" requirements in spec.
297 switch (it->xde_type) {
301 case XDE_TYPE_VOL_LABEL: {
302 struct exfat_de_label *lde = (void*)it;
303 convert_label(lde->xdel_vol_lbl,
304 lde->xdel_char_cnt, label_out, label_sz);
318 fstyp_exfat(FILE *fp, char *label, size_t size, const char *devpath)
320 struct exfat_vbr *ev;
322 unsigned bytespersec;
328 ev = (struct exfat_vbr *)read_buf(fp, 0, 512);
329 if (ev == NULL || strncmp(ev->ev_fsname, "EXFAT ", 8) != 0)
332 if (ev->ev_log_bytes_per_sect < 9 || ev->ev_log_bytes_per_sect > 12) {
333 warnx("exfat: Invalid BytesPerSectorShift");
337 bytespersec = (1u << ev->ev_log_bytes_per_sect);
339 error = exfat_compute_boot_chksum(fp, MAIN_BOOT_REGION_SECT,
340 bytespersec, &chksum);
344 cksect = read_sect(fp, MAIN_BOOT_REGION_SECT + SUBREGION_CHKSUM_SECT,
348 * Technically the entire sector should be full of repeating 4-byte
349 * checksum pattern, but we only verify the first.
351 if (chksum != le32toh(cksect[0])) {
352 warnx("exfat: Found checksum 0x%08x != computed 0x%08x",
353 le32toh(cksect[0]), chksum);
359 exfat_find_label(fp, ev, bytespersec, label, size);