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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/fs/isofs/rock.c

560 строки
15 KiB
C
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/*
* linux/fs/isofs/rock.c
*
* (C) 1992, 1993 Eric Youngdale
*
* Rock Ridge Extensions to iso9660
*/
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/smp_lock.h>
#include "isofs.h"
#include "rock.h"
/* These functions are designed to read the system areas of a directory record
* and extract relevant information. There are different functions provided
* depending upon what information we need at the time. One function fills
* out an inode structure, a second one extracts a filename, a third one
* returns a symbolic link name, and a fourth one returns the extent number
* for the file. */
#define SIG(A,B) ((A) | ((B) << 8)) /* isonum_721() */
/* This is a way of ensuring that we have something in the system
use fields that is compatible with Rock Ridge */
#define CHECK_SP(FAIL) \
if(rr->u.SP.magic[0] != 0xbe) FAIL; \
if(rr->u.SP.magic[1] != 0xef) FAIL; \
ISOFS_SB(inode->i_sb)->s_rock_offset=rr->u.SP.skip;
/* We define a series of macros because each function must do exactly the
same thing in certain places. We use the macros to ensure that everything
is done correctly */
#define CONTINUE_DECLS \
int cont_extent = 0, cont_offset = 0, cont_size = 0; \
void *buffer = NULL
#define CHECK_CE \
{cont_extent = isonum_733(rr->u.CE.extent); \
cont_offset = isonum_733(rr->u.CE.offset); \
cont_size = isonum_733(rr->u.CE.size);}
#define SETUP_ROCK_RIDGE(DE,CHR,LEN) \
{LEN= sizeof(struct iso_directory_record) + DE->name_len[0]; \
if(LEN & 1) LEN++; \
CHR = ((unsigned char *) DE) + LEN; \
LEN = *((unsigned char *) DE) - LEN; \
if (LEN<0) LEN=0; \
if (ISOFS_SB(inode->i_sb)->s_rock_offset!=-1) \
{ \
LEN-=ISOFS_SB(inode->i_sb)->s_rock_offset; \
CHR+=ISOFS_SB(inode->i_sb)->s_rock_offset; \
if (LEN<0) LEN=0; \
} \
}
#define MAYBE_CONTINUE(LABEL,DEV) \
{if (buffer) { kfree(buffer); buffer = NULL; } \
if (cont_extent){ \
int block, offset, offset1; \
struct buffer_head * pbh; \
buffer = kmalloc(cont_size,GFP_KERNEL); \
if (!buffer) goto out; \
block = cont_extent; \
offset = cont_offset; \
offset1 = 0; \
pbh = sb_bread(DEV->i_sb, block); \
if(pbh){ \
if (offset > pbh->b_size || offset + cont_size > pbh->b_size){ \
brelse(pbh); \
goto out; \
} \
memcpy(buffer + offset1, pbh->b_data + offset, cont_size - offset1); \
brelse(pbh); \
chr = (unsigned char *) buffer; \
len = cont_size; \
cont_extent = 0; \
cont_size = 0; \
cont_offset = 0; \
goto LABEL; \
} \
printk("Unable to read rock-ridge attributes\n"); \
}}
/* return length of name field; 0: not found, -1: to be ignored */
int get_rock_ridge_filename(struct iso_directory_record * de,
char * retname, struct inode * inode)
{
int len;
unsigned char * chr;
CONTINUE_DECLS;
int retnamlen = 0, truncate=0;
if (!ISOFS_SB(inode->i_sb)->s_rock) return 0;
*retname = 0;
SETUP_ROCK_RIDGE(de, chr, len);
repeat:
{
struct rock_ridge * rr;
int sig;
while (len > 2){ /* There may be one byte for padding somewhere */
rr = (struct rock_ridge *) chr;
if (rr->len < 3) goto out; /* Something got screwed up here */
sig = isonum_721(chr);
chr += rr->len;
len -= rr->len;
if (len < 0) goto out; /* corrupted isofs */
switch(sig){
case SIG('R','R'):
if((rr->u.RR.flags[0] & RR_NM) == 0) goto out;
break;
case SIG('S','P'):
CHECK_SP(goto out);
break;
case SIG('C','E'):
CHECK_CE;
break;
case SIG('N','M'):
if (truncate) break;
if (rr->len < 5) break;
/*
* If the flags are 2 or 4, this indicates '.' or '..'.
* We don't want to do anything with this, because it
* screws up the code that calls us. We don't really
* care anyways, since we can just use the non-RR
* name.
*/
if (rr->u.NM.flags & 6) {
break;
}
if (rr->u.NM.flags & ~1) {
printk("Unsupported NM flag settings (%d)\n",rr->u.NM.flags);
break;
}
if((strlen(retname) + rr->len - 5) >= 254) {
truncate = 1;
break;
}
strncat(retname, rr->u.NM.name, rr->len - 5);
retnamlen += rr->len - 5;
break;
case SIG('R','E'):
if (buffer) kfree(buffer);
return -1;
default:
break;
}
}
}
MAYBE_CONTINUE(repeat,inode);
if (buffer) kfree(buffer);
return retnamlen; /* If 0, this file did not have a NM field */
out:
if(buffer) kfree(buffer);
return 0;
}
static int
parse_rock_ridge_inode_internal(struct iso_directory_record *de,
struct inode *inode, int regard_xa)
{
int len;
unsigned char * chr;
int symlink_len = 0;
CONTINUE_DECLS;
if (!ISOFS_SB(inode->i_sb)->s_rock) return 0;
SETUP_ROCK_RIDGE(de, chr, len);
if (regard_xa)
{
chr+=14;
len-=14;
if (len<0) len=0;
}
repeat:
{
int cnt, sig;
struct inode * reloc;
struct rock_ridge * rr;
int rootflag;
while (len > 2){ /* There may be one byte for padding somewhere */
rr = (struct rock_ridge *) chr;
if (rr->len < 3) goto out; /* Something got screwed up here */
sig = isonum_721(chr);
chr += rr->len;
len -= rr->len;
if (len < 0) goto out; /* corrupted isofs */
switch(sig){
#ifndef CONFIG_ZISOFS /* No flag for SF or ZF */
case SIG('R','R'):
if((rr->u.RR.flags[0] &
(RR_PX | RR_TF | RR_SL | RR_CL)) == 0) goto out;
break;
#endif
case SIG('S','P'):
CHECK_SP(goto out);
break;
case SIG('C','E'):
CHECK_CE;
break;
case SIG('E','R'):
ISOFS_SB(inode->i_sb)->s_rock = 1;
printk(KERN_DEBUG "ISO 9660 Extensions: ");
{ int p;
for(p=0;p<rr->u.ER.len_id;p++) printk("%c",rr->u.ER.data[p]);
}
printk("\n");
break;
case SIG('P','X'):
inode->i_mode = isonum_733(rr->u.PX.mode);
inode->i_nlink = isonum_733(rr->u.PX.n_links);
inode->i_uid = isonum_733(rr->u.PX.uid);
inode->i_gid = isonum_733(rr->u.PX.gid);
break;
case SIG('P','N'):
{ int high, low;
high = isonum_733(rr->u.PN.dev_high);
low = isonum_733(rr->u.PN.dev_low);
/*
* The Rock Ridge standard specifies that if sizeof(dev_t) <= 4,
* then the high field is unused, and the device number is completely
* stored in the low field. Some writers may ignore this subtlety,
* and as a result we test to see if the entire device number is
* stored in the low field, and use that.
*/
if((low & ~0xff) && high == 0) {
inode->i_rdev = MKDEV(low >> 8, low & 0xff);
} else {
inode->i_rdev = MKDEV(high, low);
}
}
break;
case SIG('T','F'):
/* Some RRIP writers incorrectly place ctime in the TF_CREATE field.
Try to handle this correctly for either case. */
cnt = 0; /* Rock ridge never appears on a High Sierra disk */
if(rr->u.TF.flags & TF_CREATE) {
inode->i_ctime.tv_sec = iso_date(rr->u.TF.times[cnt++].time, 0);
inode->i_ctime.tv_nsec = 0;
}
if(rr->u.TF.flags & TF_MODIFY) {
inode->i_mtime.tv_sec = iso_date(rr->u.TF.times[cnt++].time, 0);
inode->i_mtime.tv_nsec = 0;
}
if(rr->u.TF.flags & TF_ACCESS) {
inode->i_atime.tv_sec = iso_date(rr->u.TF.times[cnt++].time, 0);
inode->i_atime.tv_nsec = 0;
}
if(rr->u.TF.flags & TF_ATTRIBUTES) {
inode->i_ctime.tv_sec = iso_date(rr->u.TF.times[cnt++].time, 0);
inode->i_ctime.tv_nsec = 0;
}
break;
case SIG('S','L'):
{int slen;
struct SL_component * slp;
struct SL_component * oldslp;
slen = rr->len - 5;
slp = &rr->u.SL.link;
inode->i_size = symlink_len;
while (slen > 1){
rootflag = 0;
switch(slp->flags &~1){
case 0:
inode->i_size += slp->len;
break;
case 2:
inode->i_size += 1;
break;
case 4:
inode->i_size += 2;
break;
case 8:
rootflag = 1;
inode->i_size += 1;
break;
default:
printk("Symlink component flag not implemented\n");
}
slen -= slp->len + 2;
oldslp = slp;
slp = (struct SL_component *) (((char *) slp) + slp->len + 2);
if(slen < 2) {
if( ((rr->u.SL.flags & 1) != 0)
&& ((oldslp->flags & 1) == 0) ) inode->i_size += 1;
break;
}
/*
* If this component record isn't continued, then append a '/'.
*/
if (!rootflag && (oldslp->flags & 1) == 0)
inode->i_size += 1;
}
}
symlink_len = inode->i_size;
break;
case SIG('R','E'):
printk(KERN_WARNING "Attempt to read inode for relocated directory\n");
goto out;
case SIG('C','L'):
ISOFS_I(inode)->i_first_extent = isonum_733(rr->u.CL.location);
reloc = isofs_iget(inode->i_sb, ISOFS_I(inode)->i_first_extent, 0);
if (!reloc)
goto out;
inode->i_mode = reloc->i_mode;
inode->i_nlink = reloc->i_nlink;
inode->i_uid = reloc->i_uid;
inode->i_gid = reloc->i_gid;
inode->i_rdev = reloc->i_rdev;
inode->i_size = reloc->i_size;
inode->i_blocks = reloc->i_blocks;
inode->i_atime = reloc->i_atime;
inode->i_ctime = reloc->i_ctime;
inode->i_mtime = reloc->i_mtime;
iput(reloc);
break;
#ifdef CONFIG_ZISOFS
case SIG('Z','F'):
if ( !ISOFS_SB(inode->i_sb)->s_nocompress ) {
int algo;
algo = isonum_721(rr->u.ZF.algorithm);
if ( algo == SIG('p','z') ) {
int block_shift = isonum_711(&rr->u.ZF.parms[1]);
if ( block_shift < PAGE_CACHE_SHIFT || block_shift > 17 ) {
printk(KERN_WARNING "isofs: Can't handle ZF block size of 2^%d\n", block_shift);
} else {
/* Note: we don't change i_blocks here */
ISOFS_I(inode)->i_file_format = isofs_file_compressed;
/* Parameters to compression algorithm (header size, block size) */
ISOFS_I(inode)->i_format_parm[0] = isonum_711(&rr->u.ZF.parms[0]);
ISOFS_I(inode)->i_format_parm[1] = isonum_711(&rr->u.ZF.parms[1]);
inode->i_size = isonum_733(rr->u.ZF.real_size);
}
} else {
printk(KERN_WARNING "isofs: Unknown ZF compression algorithm: %c%c\n",
rr->u.ZF.algorithm[0], rr->u.ZF.algorithm[1]);
}
}
break;
#endif
default:
break;
}
}
}
MAYBE_CONTINUE(repeat,inode);
out:
if(buffer) kfree(buffer);
return 0;
}
static char *get_symlink_chunk(char *rpnt, struct rock_ridge *rr, char *plimit)
{
int slen;
int rootflag;
struct SL_component *oldslp;
struct SL_component *slp;
slen = rr->len - 5;
slp = &rr->u.SL.link;
while (slen > 1) {
rootflag = 0;
switch (slp->flags & ~1) {
case 0:
if (slp->len > plimit - rpnt)
return NULL;
memcpy(rpnt, slp->text, slp->len);
rpnt+=slp->len;
break;
case 2:
if (rpnt >= plimit)
return NULL;
*rpnt++='.';
break;
case 4:
if (2 > plimit - rpnt)
return NULL;
*rpnt++='.';
*rpnt++='.';
break;
case 8:
if (rpnt >= plimit)
return NULL;
rootflag = 1;
*rpnt++='/';
break;
default:
printk("Symlink component flag not implemented (%d)\n",
slp->flags);
}
slen -= slp->len + 2;
oldslp = slp;
slp = (struct SL_component *) ((char *) slp + slp->len + 2);
if (slen < 2) {
/*
* If there is another SL record, and this component
* record isn't continued, then add a slash.
*/
if ((!rootflag) && (rr->u.SL.flags & 1) &&
!(oldslp->flags & 1)) {
if (rpnt >= plimit)
return NULL;
*rpnt++='/';
}
break;
}
/*
* If this component record isn't continued, then append a '/'.
*/
if (!rootflag && !(oldslp->flags & 1)) {
if (rpnt >= plimit)
return NULL;
*rpnt++='/';
}
}
return rpnt;
}
int parse_rock_ridge_inode(struct iso_directory_record * de,
struct inode * inode)
{
int result=parse_rock_ridge_inode_internal(de,inode,0);
/* if rockridge flag was reset and we didn't look for attributes
* behind eventual XA attributes, have a look there */
if ((ISOFS_SB(inode->i_sb)->s_rock_offset==-1)
&&(ISOFS_SB(inode->i_sb)->s_rock==2))
{
result=parse_rock_ridge_inode_internal(de,inode,14);
}
return result;
}
/* readpage() for symlinks: reads symlink contents into the page and either
makes it uptodate and returns 0 or returns error (-EIO) */
static int rock_ridge_symlink_readpage(struct file *file, struct page *page)
{
struct inode *inode = page->mapping->host;
struct iso_inode_info *ei = ISOFS_I(inode);
char *link = kmap(page);
unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
struct buffer_head *bh;
char *rpnt = link;
unsigned char *pnt;
struct iso_directory_record *raw_inode;
CONTINUE_DECLS;
unsigned long block, offset;
int sig;
int len;
unsigned char *chr;
struct rock_ridge *rr;
if (!ISOFS_SB(inode->i_sb)->s_rock)
goto error;
block = ei->i_iget5_block;
lock_kernel();
bh = sb_bread(inode->i_sb, block);
if (!bh)
goto out_noread;
offset = ei->i_iget5_offset;
pnt = (unsigned char *) bh->b_data + offset;
raw_inode = (struct iso_directory_record *) pnt;
/*
* If we go past the end of the buffer, there is some sort of error.
*/
if (offset + *pnt > bufsize)
goto out_bad_span;
/* Now test for possible Rock Ridge extensions which will override
some of these numbers in the inode structure. */
SETUP_ROCK_RIDGE(raw_inode, chr, len);
repeat:
while (len > 2) { /* There may be one byte for padding somewhere */
rr = (struct rock_ridge *) chr;
if (rr->len < 3)
goto out; /* Something got screwed up here */
sig = isonum_721(chr);
chr += rr->len;
len -= rr->len;
if (len < 0)
goto out; /* corrupted isofs */
switch (sig) {
case SIG('R', 'R'):
if ((rr->u.RR.flags[0] & RR_SL) == 0)
goto out;
break;
case SIG('S', 'P'):
CHECK_SP(goto out);
break;
case SIG('S', 'L'):
rpnt = get_symlink_chunk(rpnt, rr,
link + (PAGE_SIZE - 1));
if (rpnt == NULL)
goto out;
break;
case SIG('C', 'E'):
/* This tells is if there is a continuation record */
CHECK_CE;
default:
break;
}
}
MAYBE_CONTINUE(repeat, inode);
if (buffer)
kfree(buffer);
if (rpnt == link)
goto fail;
brelse(bh);
*rpnt = '\0';
unlock_kernel();
SetPageUptodate(page);
kunmap(page);
unlock_page(page);
return 0;
/* error exit from macro */
out:
if (buffer)
kfree(buffer);
goto fail;
out_noread:
printk("unable to read i-node block");
goto fail;
out_bad_span:
printk("symlink spans iso9660 blocks\n");
fail:
brelse(bh);
unlock_kernel();
error:
SetPageError(page);
kunmap(page);
unlock_page(page);
return -EIO;
}
struct address_space_operations isofs_symlink_aops = {
.readpage = rock_ridge_symlink_readpage
};
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