// SPDX-License-Identifier: GPL-2.0
/*
* QNX6 file system, Linux implementation.
*
* Version : 1.0.0
*
* History :
*
* 01-02-2012 by Kai Bankett ([email protected]) : first release.
* 16-02-2012 pagemap extension by Al Viro
*
*/
#include "qnx6.h"
static unsigned qnx6_lfile_checksum(char *name, unsigned size)
{
unsigned crc = 0;
char *end = name + size;
while (name < end) {
crc = ((crc >> 1) + *(name++)) ^
((crc & 0x00000001) ? 0x80000000 : 0);
}
return crc;
}
static void *qnx6_get_folio(struct inode *dir, unsigned long n,
struct folio **foliop)
{
struct folio *folio = read_mapping_folio(dir->i_mapping, n, NULL);
if (IS_ERR(folio))
return folio;
*foliop = folio;
return kmap_local_folio(folio, 0);
}
static unsigned last_entry(struct inode *inode, unsigned long page_nr)
{
unsigned long last_byte = inode->i_size;
last_byte -= page_nr << PAGE_SHIFT;
if (last_byte > PAGE_SIZE)
last_byte = PAGE_SIZE;
return last_byte / QNX6_DIR_ENTRY_SIZE;
}
static struct qnx6_long_filename *qnx6_longname(struct super_block *sb,
struct qnx6_long_dir_entry *de,
struct folio **foliop)
{
struct qnx6_sb_info *sbi = QNX6_SB(sb);
u32 s = fs32_to_cpu(sbi, de->de_long_inode); /* in block units */
u32 n = s >> (PAGE_SHIFT - sb->s_blocksize_bits); /* in pages */
u32 offs;
struct address_space *mapping = sbi->longfile->i_mapping;
struct folio *folio = read_mapping_folio(mapping, n, NULL);
if (IS_ERR(folio))
return ERR_CAST(folio);
offs = offset_in_folio(folio, s << sb->s_blocksize_bits);
*foliop = folio;
return kmap_local_folio(folio, offs);
}
static int qnx6_dir_longfilename(struct inode *inode,
struct qnx6_long_dir_entry *de,
struct dir_context *ctx,
unsigned de_inode)
{
struct qnx6_long_filename *lf;
struct super_block *s = inode->i_sb;
struct qnx6_sb_info *sbi = QNX6_SB(s);
struct folio *folio;
int lf_size;
if (de->de_size != 0xff) {
/* error - long filename entries always have size 0xff
in direntry */
pr_err("invalid direntry size (%i).\n", de->de_size);
return 0;
}
lf = qnx6_longname(s, de, &folio);
if (IS_ERR(lf)) {
pr_err("Error reading longname\n");
return 0;
}
lf_size = fs16_to_cpu(sbi, lf->lf_size);
if (lf_size > QNX6_LONG_NAME_MAX) {
pr_debug("file %s\n", lf->lf_fname);
pr_err("Filename too long (%i)\n", lf_size);
folio_release_kmap(folio, lf);
return 0;
}
/* calc & validate longfilename checksum
mmi 3g filesystem does not have that checksum */
if (!test_opt(s, MMI_FS) && fs32_to_cpu(sbi, de->de_checksum) !=
qnx6_lfile_checksum(lf->lf_fname, lf_size))
pr_info("long filename checksum error.\n");
pr_debug("qnx6_readdir:%.*s inode:%u\n",
lf_size, lf->lf_fname, de_inode);
if (!dir_emit(ctx, lf->lf_fname, lf_size, de_inode, DT_UNKNOWN)) {
folio_release_kmap(folio, lf);
return 0;
}
folio_release_kmap(folio, lf);
/* success */
return 1;
}
static int qnx6_readdir(struct file *file, struct dir_context *ctx)
{
struct inode *inode = file_inode(file);
struct super_block *s = inode->i_sb;
struct qnx6_sb_info *sbi = QNX6_SB(s);
loff_t pos = ctx->pos & ~(QNX6_DIR_ENTRY_SIZE - 1);
unsigned long npages = dir_pages(inode);
unsigned long n = pos >> PAGE_SHIFT;
unsigned offset = (pos & ~PAGE_MASK) / QNX6_DIR_ENTRY_SIZE;
bool done = false;
ctx->pos = pos;
if (ctx->pos >= inode->i_size)
return 0;
for ( ; !done && n < npages; n++, offset = 0) {
struct qnx6_dir_entry *de;
struct folio *folio;
char *kaddr = qnx6_get_folio(inode, n, &folio);
char *limit;
if (IS_ERR(kaddr)) {
pr_err("%s(): read failed\n", __func__);
ctx->pos = (n + 1) << PAGE_SHIFT;
return PTR_ERR(kaddr);
}
de = (struct qnx6_dir_entry *)(kaddr + offset);
limit = kaddr + last_entry(inode, n);
for (; (char *)de < limit; de++, ctx->pos += QNX6_DIR_ENTRY_SIZE) {
int size = de->de_size;
u32 no_inode = fs32_to_cpu(sbi, de->de_inode);
if (!no_inode || !size)
continue;
if (size > QNX6_SHORT_NAME_MAX) {
/* long filename detected
get the filename from long filename
structure / block */
if (!qnx6_dir_longfilename(inode,
(struct qnx6_long_dir_entry *)de,
ctx, no_inode)) {
done = true;
break;
}
} else {
pr_debug("%s():%.*s inode:%u\n",
__func__, size, de->de_fname,
no_inode);
if (!dir_emit(ctx, de->de_fname, size,
no_inode, DT_UNKNOWN)) {
done = true;
break;
}
}
}
folio_release_kmap(folio, kaddr);
}
return 0;
}
/*
* check if the long filename is correct.
*/
static unsigned qnx6_long_match(int len, const char *name,
struct qnx6_long_dir_entry *de, struct inode *dir)
{
struct super_block *s = dir->i_sb;
struct qnx6_sb_info *sbi = QNX6_SB(s);
struct folio *folio;
int thislen;
struct qnx6_long_filename *lf = qnx6_longname(s, de, &folio);
if (IS_ERR(lf))
return 0;
thislen = fs16_to_cpu(sbi, lf->lf_size);
if (len != thislen) {
folio_release_kmap(folio, lf);
return 0;
}
if (memcmp(name, lf->lf_fname, len) == 0) {
folio_release_kmap(folio, lf);
return fs32_to_cpu(sbi, de->de_inode);
}
folio_release_kmap(folio, lf);
return 0;
}
/*
* check if the filename is correct.
*/
static unsigned qnx6_match(struct super_block *s, int len, const char *name,
struct qnx6_dir_entry *de)
{
struct qnx6_sb_info *sbi = QNX6_SB(s);
if (memcmp(name, de->de_fname, len) == 0)
return fs32_to_cpu(sbi, de->de_inode);
return 0;
}
unsigned qnx6_find_ino(int len, struct inode *dir, const char *name)
{
struct super_block *s = dir->i_sb;
struct qnx6_inode_info *ei = QNX6_I(dir);
struct folio *folio;
unsigned long start, n;
unsigned long npages = dir_pages(dir);
unsigned ino;
struct qnx6_dir_entry *de;
struct qnx6_long_dir_entry *lde;
if (npages == 0)
return 0;
start = ei->i_dir_start_lookup;
if (start >= npages)
start = 0;
n = start;
do {
de = qnx6_get_folio(dir, n, &folio);
if (!IS_ERR(de)) {
int limit = last_entry(dir, n);
int i;
for (i = 0; i < limit; i++, de++) {
if (len <= QNX6_SHORT_NAME_MAX) {
/* short filename */
if (len != de->de_size)
continue;
ino = qnx6_match(s, len, name, de);
if (ino)
goto found;
} else if (de->de_size == 0xff) {
/* deal with long filename */
lde = (struct qnx6_long_dir_entry *)de;
ino = qnx6_long_match(len,
name, lde, dir);
if (ino)
goto found;
} else
pr_err("undefined filename size in inode.\n");
}
folio_release_kmap(folio, de - i);
}
if (++n >= npages)
n = 0;
} while (n != start);
return 0;
found:
ei->i_dir_start_lookup = n;
folio_release_kmap(folio, de);
return ino;
}
const struct file_operations qnx6_dir_operations = {
.llseek = generic_file_llseek,
.read = generic_read_dir,
.iterate_shared = qnx6_readdir,
.fsync = generic_file_fsync,
};
const struct inode_operations qnx6_dir_inode_operations = {
.lookup = qnx6_lookup,
};
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