/* 
 * This code is based on the ISO filesystem support in MILO (by
 * Dave Rusling).
 *
 * This is a set of functions that provides minimal filesystem
 * functionality to the Linux bootstrapper.  All we can do is
 * open and read files... but that's all we need 8-)
 */
#include <linux/stat.h>
#include <sys/types.h>

#include "string.h"
#include "iso.h"
#include "isolib.h"
#include "utils.h"

/* iso9660 support code */

#define MAX_OPEN_FILES 5

static struct inode_table_entry {
    struct iso_inode inode;
    int inumber;
    int free;
    unsigned short old_mode;
    unsigned size;
    int nlink;
    int mode;
    void *start;
} inode_table[MAX_OPEN_FILES];

static unsigned long root_inode = 0;
static struct isofs_super_block sb;
static char data_block[1024];
static char big_data_block[2048];

#ifndef S_IRWXUGO
# define S_IRWXUGO	(S_IRWXU|S_IRWXG|S_IRWXO)
# define S_IXUGO	(S_IXUSR|S_IXGRP|S_IXOTH)
# define S_IRUGO	(S_IRUSR|S_IRGRP|S_IROTH)
#endif

extern long iso_dev_read (void * buf, long offset, long size);

static int parse_rock_ridge_inode(struct iso_directory_record * de,
				  struct iso_inode * inode);
static char *get_rock_ridge_symlink(struct iso_inode *inode);
static int get_rock_ridge_filename(struct iso_directory_record * de,
				   char * retname,
				   struct iso_inode * inode);

int
isonum_711 (char * p)
{
	return (*p & 0xff);
}


int
isonum_712 (char * p)
{
	int val;

	val = *p;
	if (val & 0x80)
		val |= 0xffffff00;
	return val;
}


int
isonum_721 (char * p)
{
	return ((p[0] & 0xff) | ((p[1] & 0xff) << 8));
}

int
isonum_722 (char * p)
{
	return (((p[0] & 0xff) << 8) | (p[1] & 0xff));
}


int
isonum_723 (char * p)
{
	return isonum_721(p);
}


int
isonum_731 (char * p)
{
	return ((p[0] & 0xff)
		| ((p[1] & 0xff) << 8)
		| ((p[2] & 0xff) << 16)
		| ((p[3] & 0xff) << 24));
}


int
isonum_732 (char * p)
{
	return (((p[0] & 0xff) << 24)
		| ((p[1] & 0xff) << 16)
		| ((p[2] & 0xff) << 8)
		| (p[3] & 0xff));
}


int
isonum_733 (char * p)
{
	return isonum_731(p);
}


static int
iso_bmap (struct iso_inode *inode, int block)
{
	if (block < 0) {
		printf("iso_bmap: block<0");
		return 0;
	}
	return (inode->i_first_extent >> sb.s_blocksize_bits) + block;
}

static int
iso_breadi (struct iso_inode *ip, long blkno, long nblks, char * buffer)
{
	long i_size, abs_blkno;

	/* do some error checking */
	if (!ip || !ip->i_first_extent)
		return -1;

	i_size = ((struct inode_table_entry *) ip)->size;
	/* as in ext2.c - cons_read() doesn't really cope well with
           EOF conditions - actually it should be fixed */
	if ((blkno+nblks) * sb.s_blocksize > i_size)
		nblks = ((i_size + sb.s_blocksize)
			 / sb.s_blocksize) - blkno;

	/* figure out which iso block number(s) we're being asked for */
	abs_blkno = iso_bmap(ip, blkno);
	if (!abs_blkno)
		return -1;
	/* now try and read them (easy since ISO files are continguous) */
	return iso_dev_read(buffer, abs_blkno * sb.s_blocksize,
			    nblks * sb.s_blocksize);
}


/*
 * Release our hold on an inode.  Since this is a read-only application,
 * don't worry about putting back any changes...
 */
static void
iso_iput (struct iso_inode *ip)
{
	struct inode_table_entry *itp;

	/* Find and free the inode table slot we used... */
	itp = (struct inode_table_entry *) ip;

	itp->inumber = 0;
	itp->free = 1;
}

/*
 * Read the specified inode from the disk and return it to the user.
 * Returns NULL if the inode can't be read...
 *
 * Uses data_block
 */
static struct iso_inode *
iso_iget (int ino)
{
	int i;
	struct iso_inode *inode;
	struct inode_table_entry *itp;
	struct iso_directory_record * raw_inode;
	unsigned char *pnt = NULL;
	void *cpnt = NULL;
	int high_sierra;
	int block;

#ifdef DEBUG_ISO
	printf("iso_iget(ino=%d)\n", ino);
#endif

	/* find a free inode to play with */
	inode = NULL;
	itp = NULL;
	for (i = 0; i < MAX_OPEN_FILES; i++) {
		if (inode_table[i].free) {
			itp = &(inode_table[i]);
			inode = &(itp->inode);
			break;
		}
	}
	if ((inode == NULL) || (itp == NULL)) {
		printf("iso9660 (iget): no free inodes\n");
		return (NULL);
	}

	block = ino >> sb.s_blocksize_bits;
	if (iso_dev_read(data_block, block * sb.s_blocksize, sb.s_blocksize)
	    != sb.s_blocksize) {
		printf("iso9660: unable to read i-node block");
		return NULL;
	}

	pnt = ((unsigned char *) data_block + (ino & (sb.s_blocksize - 1)));
	raw_inode = ((struct iso_directory_record *) pnt);
	high_sierra = sb.s_high_sierra;

	if ((ino & (sb.s_blocksize - 1)) + *pnt > sb.s_blocksize){
		int frag1, offset;

		offset = (ino & (sb.s_blocksize - 1));
		frag1 = sb.s_blocksize - offset;
		cpnt = big_data_block;
		memcpy(cpnt, data_block + offset, frag1);
		offset += *pnt - sb.s_blocksize; /* DUH! pnt would get
                                                    wiped out by the
                                                    iso_dev_read here. */
		if (iso_dev_read(data_block, ++block * sb.s_blocksize,
				 sb.s_blocksize)
		    != sb.s_blocksize) {
			printf("unable to read i-node block");
			return NULL;
		}
		memcpy((char *)cpnt+frag1, data_block, offset);
		pnt = ((unsigned char *) cpnt);
		raw_inode = ((struct iso_directory_record *) pnt);
	}

	if (raw_inode->flags[-high_sierra] & 2) {
		itp->mode = S_IRUGO | S_IXUGO | S_IFDIR;
		itp->nlink = 1; /* Set to 1.  We know there are 2, but
				   the find utility tries to optimize
				   if it is 2, and it screws up.  It is
				   easier to give 1 which tells find to
				   do it the hard way. */
	} else {
		itp->mode = sb.s_mode; /* Everybody gets to read the file. */
		itp->nlink = 1;
		itp->mode |= S_IFREG;
		/*
		 * If there are no periods in the name, then set the
		 * execute permission bit
		 */
		for(i=0; i< raw_inode->name_len[0]; i++)
			if(raw_inode->name[i]=='.' || raw_inode->name[i]==';')
				break;
		if(i == raw_inode->name_len[0] || raw_inode->name[i] == ';') 
			itp->mode |= S_IXUGO; /* execute permission */
	}

	itp->size = isonum_733 (raw_inode->size);

	/* There are defective discs out there - we do this to protect
	   ourselves.  A cdrom will never contain more than 700Mb */
	if((itp->size < 0 || itp->size > 700000000) &&
	   sb.s_cruft == 'n')
	{
		printf("Warning: defective cdrom.  "