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