diff options
Diffstat (limited to 'fs/isofs/rock.c')
| -rw-r--r-- | fs/isofs/rock.c | 565 |
1 files changed, 565 insertions, 0 deletions
diff --git a/fs/isofs/rock.c b/fs/isofs/rock.c new file mode 100644 index 000000000000..8bdd3e409543 --- /dev/null +++ b/fs/isofs/rock.c @@ -0,0 +1,565 @@ +/* + * linux/fs/isofs/rock.c + * + * (C) 1992, 1993 Eric Youngdale + * + * Rock Ridge Extensions to iso9660 + */ + +#include <linux/stat.h> +#include <linux/time.h> +#include <linux/iso_fs.h> +#include <linux/string.h> +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/pagemap.h> +#include <linux/smp_lock.h> +#include <linux/buffer_head.h> +#include <asm/page.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 +}; |