1d2912cb1SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only
21da177e4SLinus Torvalds /*
31da177e4SLinus Torvalds * linux/fs/adfs/dir_f.c
41da177e4SLinus Torvalds *
51da177e4SLinus Torvalds * Copyright (C) 1997-1999 Russell King
61da177e4SLinus Torvalds *
71da177e4SLinus Torvalds * E and F format directory handling
81da177e4SLinus Torvalds */
91da177e4SLinus Torvalds #include "adfs.h"
101da177e4SLinus Torvalds #include "dir_f.h"
111da177e4SLinus Torvalds
121da177e4SLinus Torvalds /*
131da177e4SLinus Torvalds * Read an (unaligned) value of length 1..4 bytes
141da177e4SLinus Torvalds */
adfs_readval(unsigned char * p,int len)151da177e4SLinus Torvalds static inline unsigned int adfs_readval(unsigned char *p, int len)
161da177e4SLinus Torvalds {
171da177e4SLinus Torvalds unsigned int val = 0;
181da177e4SLinus Torvalds
191da177e4SLinus Torvalds switch (len) {
201da177e4SLinus Torvalds case 4: val |= p[3] << 24;
21df561f66SGustavo A. R. Silva fallthrough;
221da177e4SLinus Torvalds case 3: val |= p[2] << 16;
23df561f66SGustavo A. R. Silva fallthrough;
241da177e4SLinus Torvalds case 2: val |= p[1] << 8;
25df561f66SGustavo A. R. Silva fallthrough;
261da177e4SLinus Torvalds default: val |= p[0];
271da177e4SLinus Torvalds }
281da177e4SLinus Torvalds return val;
291da177e4SLinus Torvalds }
301da177e4SLinus Torvalds
adfs_writeval(unsigned char * p,int len,unsigned int val)311da177e4SLinus Torvalds static inline void adfs_writeval(unsigned char *p, int len, unsigned int val)
321da177e4SLinus Torvalds {
331da177e4SLinus Torvalds switch (len) {
341da177e4SLinus Torvalds case 4: p[3] = val >> 24;
35df561f66SGustavo A. R. Silva fallthrough;
361da177e4SLinus Torvalds case 3: p[2] = val >> 16;
37df561f66SGustavo A. R. Silva fallthrough;
381da177e4SLinus Torvalds case 2: p[1] = val >> 8;
39df561f66SGustavo A. R. Silva fallthrough;
401da177e4SLinus Torvalds default: p[0] = val;
411da177e4SLinus Torvalds }
421da177e4SLinus Torvalds }
431da177e4SLinus Torvalds
441da177e4SLinus Torvalds #define ror13(v) ((v >> 13) | (v << 19))
451da177e4SLinus Torvalds
461da177e4SLinus Torvalds #define dir_u8(idx) \
471da177e4SLinus Torvalds ({ int _buf = idx >> blocksize_bits; \
481da177e4SLinus Torvalds int _off = idx - (_buf << blocksize_bits);\
491da177e4SLinus Torvalds *(u8 *)(bh[_buf]->b_data + _off); \
501da177e4SLinus Torvalds })
511da177e4SLinus Torvalds
521da177e4SLinus Torvalds #define dir_u32(idx) \
531da177e4SLinus Torvalds ({ int _buf = idx >> blocksize_bits; \
541da177e4SLinus Torvalds int _off = idx - (_buf << blocksize_bits);\
551da177e4SLinus Torvalds *(__le32 *)(bh[_buf]->b_data + _off); \
561da177e4SLinus Torvalds })
571da177e4SLinus Torvalds
581da177e4SLinus Torvalds #define bufoff(_bh,_idx) \
591da177e4SLinus Torvalds ({ int _buf = _idx >> blocksize_bits; \
601da177e4SLinus Torvalds int _off = _idx - (_buf << blocksize_bits);\
61016936b3SRussell King (void *)(_bh[_buf]->b_data + _off); \
621da177e4SLinus Torvalds })
631da177e4SLinus Torvalds
641da177e4SLinus Torvalds /*
651da177e4SLinus Torvalds * There are some algorithms that are nice in
661da177e4SLinus Torvalds * assembler, but a bitch in C... This is one
671da177e4SLinus Torvalds * of them.
681da177e4SLinus Torvalds */
691da177e4SLinus Torvalds static u8
adfs_dir_checkbyte(const struct adfs_dir * dir)701da177e4SLinus Torvalds adfs_dir_checkbyte(const struct adfs_dir *dir)
711da177e4SLinus Torvalds {
721da177e4SLinus Torvalds struct buffer_head * const *bh = dir->bh;
731da177e4SLinus Torvalds const int blocksize_bits = dir->sb->s_blocksize_bits;
741da177e4SLinus Torvalds union { __le32 *ptr32; u8 *ptr8; } ptr, end;
751da177e4SLinus Torvalds u32 dircheck = 0;
761da177e4SLinus Torvalds int last = 5 - 26;
771da177e4SLinus Torvalds int i = 0;
781da177e4SLinus Torvalds
791da177e4SLinus Torvalds /*
801da177e4SLinus Torvalds * Accumulate each word up to the last whole
811da177e4SLinus Torvalds * word of the last directory entry. This
821da177e4SLinus Torvalds * can spread across several buffer heads.
831da177e4SLinus Torvalds */
841da177e4SLinus Torvalds do {
851da177e4SLinus Torvalds last += 26;
861da177e4SLinus Torvalds do {
871da177e4SLinus Torvalds dircheck = le32_to_cpu(dir_u32(i)) ^ ror13(dircheck);
881da177e4SLinus Torvalds
891da177e4SLinus Torvalds i += sizeof(u32);
901da177e4SLinus Torvalds } while (i < (last & ~3));
911da177e4SLinus Torvalds } while (dir_u8(last) != 0);
921da177e4SLinus Torvalds
931da177e4SLinus Torvalds /*
941da177e4SLinus Torvalds * Accumulate the last few bytes. These
951da177e4SLinus Torvalds * bytes will be within the same bh.
961da177e4SLinus Torvalds */
971da177e4SLinus Torvalds if (i != last) {
981da177e4SLinus Torvalds ptr.ptr8 = bufoff(bh, i);
991da177e4SLinus Torvalds end.ptr8 = ptr.ptr8 + last - i;
1001da177e4SLinus Torvalds
101e5949050SHarvey Harrison do {
1021da177e4SLinus Torvalds dircheck = *ptr.ptr8++ ^ ror13(dircheck);
103e5949050SHarvey Harrison } while (ptr.ptr8 < end.ptr8);
1041da177e4SLinus Torvalds }
1051da177e4SLinus Torvalds
1061da177e4SLinus Torvalds /*
1071da177e4SLinus Torvalds * The directory tail is in the final bh
1081da177e4SLinus Torvalds * Note that contary to the RISC OS PRMs,
1091da177e4SLinus Torvalds * the first few bytes are NOT included
1101da177e4SLinus Torvalds * in the check. All bytes are in the
1111da177e4SLinus Torvalds * same bh.
1121da177e4SLinus Torvalds */
1131da177e4SLinus Torvalds ptr.ptr8 = bufoff(bh, 2008);
1141da177e4SLinus Torvalds end.ptr8 = ptr.ptr8 + 36;
1151da177e4SLinus Torvalds
1161da177e4SLinus Torvalds do {
1171da177e4SLinus Torvalds __le32 v = *ptr.ptr32++;
1181da177e4SLinus Torvalds dircheck = le32_to_cpu(v) ^ ror13(dircheck);
1191da177e4SLinus Torvalds } while (ptr.ptr32 < end.ptr32);
1201da177e4SLinus Torvalds
1211da177e4SLinus Torvalds return (dircheck ^ (dircheck >> 8) ^ (dircheck >> 16) ^ (dircheck >> 24)) & 0xff;
1221da177e4SLinus Torvalds }
1231da177e4SLinus Torvalds
adfs_f_validate(struct adfs_dir * dir)124ffc8df34SRussell King static int adfs_f_validate(struct adfs_dir *dir)
125ffc8df34SRussell King {
126ffc8df34SRussell King struct adfs_dirheader *head = dir->dirhead;
127ffc8df34SRussell King struct adfs_newdirtail *tail = dir->newtail;
128ffc8df34SRussell King
129ffc8df34SRussell King if (head->startmasseq != tail->endmasseq ||
1307a0e4048SRussell King tail->dirlastmask || tail->reserved[0] || tail->reserved[1] ||
131ffc8df34SRussell King (memcmp(&head->startname, "Nick", 4) &&
132ffc8df34SRussell King memcmp(&head->startname, "Hugo", 4)) ||
133ffc8df34SRussell King memcmp(&head->startname, &tail->endname, 4) ||
134ffc8df34SRussell King adfs_dir_checkbyte(dir) != tail->dircheckbyte)
135ffc8df34SRussell King return -EIO;
136ffc8df34SRussell King
137ffc8df34SRussell King return 0;
138ffc8df34SRussell King }
139ffc8df34SRussell King
1405ed70bb4SRussell King /* Read and check that a directory is valid */
adfs_f_read(struct super_block * sb,u32 indaddr,unsigned int size,struct adfs_dir * dir)1419318731bSRussell King static int adfs_f_read(struct super_block *sb, u32 indaddr, unsigned int size,
1429318731bSRussell King struct adfs_dir *dir)
1431da177e4SLinus Torvalds {
1441da177e4SLinus Torvalds const unsigned int blocksize_bits = sb->s_blocksize_bits;
145419a6e5eSRussell King int ret;
1461da177e4SLinus Torvalds
1479318731bSRussell King if (size && size != ADFS_NEWDIR_SIZE)
1489318731bSRussell King return -EIO;
1491da177e4SLinus Torvalds
1509318731bSRussell King ret = adfs_dir_read_buffers(sb, indaddr, ADFS_NEWDIR_SIZE, dir);
151419a6e5eSRussell King if (ret)
152419a6e5eSRussell King return ret;
1531da177e4SLinus Torvalds
154016936b3SRussell King dir->dirhead = bufoff(dir->bh, 0);
155016936b3SRussell King dir->newtail = bufoff(dir->bh, 2007);
1561da177e4SLinus Torvalds
157ffc8df34SRussell King if (adfs_f_validate(dir))
1581da177e4SLinus Torvalds goto bad_dir;
1591da177e4SLinus Torvalds
1609318731bSRussell King dir->parent_id = adfs_readval(dir->newtail->dirparent, 3);
1619318731bSRussell King
1621da177e4SLinus Torvalds return 0;
1631da177e4SLinus Torvalds
1641da177e4SLinus Torvalds bad_dir:
1655ed70bb4SRussell King adfs_error(sb, "dir %06x is corrupted", indaddr);
1661dd9f5baSRussell King adfs_dir_relse(dir);
1671da177e4SLinus Torvalds
1681da177e4SLinus Torvalds return -EIO;
1691da177e4SLinus Torvalds }
1701da177e4SLinus Torvalds
1711da177e4SLinus Torvalds /*
1721da177e4SLinus Torvalds * convert a disk-based directory entry to a Linux ADFS directory entry
1731da177e4SLinus Torvalds */
1741da177e4SLinus Torvalds static inline void
adfs_dir2obj(struct adfs_dir * dir,struct object_info * obj,struct adfs_direntry * de)175da23ef05SStuart Swales adfs_dir2obj(struct adfs_dir *dir, struct object_info *obj,
176da23ef05SStuart Swales struct adfs_direntry *de)
1771da177e4SLinus Torvalds {
178adb514a4SRussell King unsigned int name_len;
179adb514a4SRussell King
180adb514a4SRussell King for (name_len = 0; name_len < ADFS_F_NAME_LEN; name_len++) {
181adb514a4SRussell King if (de->dirobname[name_len] < ' ')
182adb514a4SRussell King break;
183adb514a4SRussell King
184adb514a4SRussell King obj->name[name_len] = de->dirobname[name_len];
185adb514a4SRussell King }
186adb514a4SRussell King
187adb514a4SRussell King obj->name_len = name_len;
1885ed70bb4SRussell King obj->indaddr = adfs_readval(de->dirinddiscadd, 3);
1891da177e4SLinus Torvalds obj->loadaddr = adfs_readval(de->dirload, 4);
1901da177e4SLinus Torvalds obj->execaddr = adfs_readval(de->direxec, 4);
1911da177e4SLinus Torvalds obj->size = adfs_readval(de->dirlen, 4);
1921da177e4SLinus Torvalds obj->attr = de->newdiratts;
193da23ef05SStuart Swales
194411c49bcSRussell King adfs_object_fixup(dir, obj);
1951da177e4SLinus Torvalds }
1961da177e4SLinus Torvalds
1971da177e4SLinus Torvalds /*
1981da177e4SLinus Torvalds * convert a Linux ADFS directory entry to a disk-based directory entry
1991da177e4SLinus Torvalds */
2001da177e4SLinus Torvalds static inline void
adfs_obj2dir(struct adfs_direntry * de,struct object_info * obj)2011da177e4SLinus Torvalds adfs_obj2dir(struct adfs_direntry *de, struct object_info *obj)
2021da177e4SLinus Torvalds {
2035ed70bb4SRussell King adfs_writeval(de->dirinddiscadd, 3, obj->indaddr);
2041da177e4SLinus Torvalds adfs_writeval(de->dirload, 4, obj->loadaddr);
2051da177e4SLinus Torvalds adfs_writeval(de->direxec, 4, obj->execaddr);
2061da177e4SLinus Torvalds adfs_writeval(de->dirlen, 4, obj->size);
2071da177e4SLinus Torvalds de->newdiratts = obj->attr;
2081da177e4SLinus Torvalds }
2091da177e4SLinus Torvalds
2101da177e4SLinus Torvalds /*
2111da177e4SLinus Torvalds * get a directory entry. Note that the caller is responsible
2121da177e4SLinus Torvalds * for holding the relevant locks.
2131da177e4SLinus Torvalds */
2141da177e4SLinus Torvalds static int
__adfs_dir_get(struct adfs_dir * dir,int pos,struct object_info * obj)2151da177e4SLinus Torvalds __adfs_dir_get(struct adfs_dir *dir, int pos, struct object_info *obj)
2161da177e4SLinus Torvalds {
2171da177e4SLinus Torvalds struct adfs_direntry de;
218a317120bSRussell King int ret;
2191da177e4SLinus Torvalds
220a317120bSRussell King ret = adfs_dir_copyfrom(&de, dir, pos, 26);
221a317120bSRussell King if (ret)
222a317120bSRussell King return ret;
2231da177e4SLinus Torvalds
2241da177e4SLinus Torvalds if (!de.dirobname[0])
2251da177e4SLinus Torvalds return -ENOENT;
2261da177e4SLinus Torvalds
227da23ef05SStuart Swales adfs_dir2obj(dir, obj, &de);
2281da177e4SLinus Torvalds
2291da177e4SLinus Torvalds return 0;
2301da177e4SLinus Torvalds }
2311da177e4SLinus Torvalds
2321da177e4SLinus Torvalds static int
adfs_f_setpos(struct adfs_dir * dir,unsigned int fpos)2331da177e4SLinus Torvalds adfs_f_setpos(struct adfs_dir *dir, unsigned int fpos)
2341da177e4SLinus Torvalds {
2351da177e4SLinus Torvalds if (fpos >= ADFS_NUM_DIR_ENTRIES)
2361da177e4SLinus Torvalds return -ENOENT;
2371da177e4SLinus Torvalds
2381da177e4SLinus Torvalds dir->pos = 5 + fpos * 26;
2391da177e4SLinus Torvalds return 0;
2401da177e4SLinus Torvalds }
2411da177e4SLinus Torvalds
2421da177e4SLinus Torvalds static int
adfs_f_getnext(struct adfs_dir * dir,struct object_info * obj)2431da177e4SLinus Torvalds adfs_f_getnext(struct adfs_dir *dir, struct object_info *obj)
2441da177e4SLinus Torvalds {
2451da177e4SLinus Torvalds unsigned int ret;
2461da177e4SLinus Torvalds
2471da177e4SLinus Torvalds ret = __adfs_dir_get(dir, dir->pos, obj);
2481da177e4SLinus Torvalds if (ret == 0)
2491da177e4SLinus Torvalds dir->pos += 26;
2501da177e4SLinus Torvalds
2511da177e4SLinus Torvalds return ret;
2521da177e4SLinus Torvalds }
2531da177e4SLinus Torvalds
adfs_f_iterate(struct adfs_dir * dir,struct dir_context * ctx)2544287e4deSRussell King static int adfs_f_iterate(struct adfs_dir *dir, struct dir_context *ctx)
2554287e4deSRussell King {
2564287e4deSRussell King struct object_info obj;
2574287e4deSRussell King int pos = 5 + (ctx->pos - 2) * 26;
2584287e4deSRussell King
2594287e4deSRussell King while (ctx->pos < 2 + ADFS_NUM_DIR_ENTRIES) {
2604287e4deSRussell King if (__adfs_dir_get(dir, pos, &obj))
2614287e4deSRussell King break;
2624287e4deSRussell King if (!dir_emit(ctx, obj.name, obj.name_len,
2634287e4deSRussell King obj.indaddr, DT_UNKNOWN))
2644287e4deSRussell King break;
2654287e4deSRussell King pos += 26;
2664287e4deSRussell King ctx->pos++;
2674287e4deSRussell King }
2684287e4deSRussell King return 0;
2694287e4deSRussell King }
2704287e4deSRussell King
adfs_f_update(struct adfs_dir * dir,struct object_info * obj)271cc625ccdSRussell King static int adfs_f_update(struct adfs_dir *dir, struct object_info *obj)
2721da177e4SLinus Torvalds {
273cc625ccdSRussell King struct adfs_direntry de;
274cc625ccdSRussell King int offset, ret;
2751da177e4SLinus Torvalds
276cc625ccdSRussell King offset = 5 - (int)sizeof(de);
277cc625ccdSRussell King
278cc625ccdSRussell King do {
279cc625ccdSRussell King offset += sizeof(de);
280cc625ccdSRussell King ret = adfs_dir_copyfrom(&de, dir, offset, sizeof(de));
281cc625ccdSRussell King if (ret) {
282cc625ccdSRussell King adfs_error(dir->sb, "error reading directory entry");
283cc625ccdSRussell King return -ENOENT;
2841da177e4SLinus Torvalds }
285cc625ccdSRussell King if (!de.dirobname[0]) {
286cc625ccdSRussell King adfs_error(dir->sb, "unable to locate entry to update");
287cc625ccdSRussell King return -ENOENT;
288cc625ccdSRussell King }
289cc625ccdSRussell King } while (adfs_readval(de.dirinddiscadd, 3) != obj->indaddr);
2901da177e4SLinus Torvalds
291cc625ccdSRussell King /* Update the directory entry with the new object state */
292cc625ccdSRussell King adfs_obj2dir(&de, obj);
293cc625ccdSRussell King
294cc625ccdSRussell King /* Write the directory entry back to the directory */
295aacc954cSRussell King return adfs_dir_copyto(dir, offset, &de, 26);
296aacc954cSRussell King }
2971da177e4SLinus Torvalds
adfs_f_commit(struct adfs_dir * dir)298aacc954cSRussell King static int adfs_f_commit(struct adfs_dir *dir)
299aacc954cSRussell King {
300aacc954cSRussell King int ret;
301aacc954cSRussell King
302aacc954cSRussell King /* Increment directory sequence number */
303016936b3SRussell King dir->dirhead->startmasseq += 1;
304016936b3SRussell King dir->newtail->endmasseq += 1;
3051da177e4SLinus Torvalds
306aacc954cSRussell King /* Update directory check byte */
307aacc954cSRussell King dir->newtail->dircheckbyte = adfs_dir_checkbyte(dir);
3081da177e4SLinus Torvalds
309aacc954cSRussell King /* Make sure the directory still validates correctly */
310ffc8df34SRussell King ret = adfs_f_validate(dir);
311ffc8df34SRussell King if (ret)
312aacc954cSRussell King adfs_msg(dir->sb, KERN_ERR, "error: update broke directory");
313ffc8df34SRussell King
314ffc8df34SRussell King return ret;
3151da177e4SLinus Torvalds }
3161da177e4SLinus Torvalds
3170125f504SJulia Lawall const struct adfs_dir_ops adfs_f_dir_ops = {
3181da177e4SLinus Torvalds .read = adfs_f_read,
3194287e4deSRussell King .iterate = adfs_f_iterate,
3201da177e4SLinus Torvalds .setpos = adfs_f_setpos,
3211da177e4SLinus Torvalds .getnext = adfs_f_getnext,
3221da177e4SLinus Torvalds .update = adfs_f_update,
323aacc954cSRussell King .commit = adfs_f_commit,
3241da177e4SLinus Torvalds };
325