iso9660 endianness cleanup patch

H. Peter Anvin
2001-05-01T05:31:26Z

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Hi guys,

I was looking over the iso9660 code, and noticed that it was doing
endianness conversion via ad hoc *functions*, not even inlines; nor did
it take any advantage of the fact that iso9660 is bi-endian (has "all"
data in both bigendian and littleendian format.)

The attached patch fixes both. It is against 2.4.4, but from the looks
of it it should patch against -ac as well.

-hpa

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--- linux-2.4.4/include/linux/iso_fs.h Fri Apr 27 15:48:20 2001
+++ linux-2.4.4-ciso/include/linux/iso_fs.h Mon Apr 30 20:09:31 2001
@@ -165,14 +165,51 @@
#define ISOFS_SUPER_MAGIC 0x9660

#ifdef __KERNEL__
-extern int isonum_711(char *);
-extern int isonum_712(char *);
-extern int isonum_721(char *);
-extern int isonum_722(char *);
-extern int isonum_723(char *);
-extern int isonum_731(char *);
-extern int isonum_732(char *);
-extern int isonum_733(char *);
+/* Number conversion inlines, named after the section in ISO 9660
+ they correspond to. */
+
+#include <asm/byteorder.h>
+
+extern inline int isonum_711(char *p)
+{
+ return *(u8 *)p;
+}
+extern inline int isonum_712(char *p)
+{
+ return *(s8 *)p;
+}
+extern inline int isonum_721(char *p)
+{
+ return le16_to_cpu(*(u16 *)p);
+}
+extern inline int isonum_722(char *p)
+{
+ return be16_to_cpu(*(u16 *)p);
+}
+extern inline int isonum_723(char *p)
+{
+#ifdef __BIG_ENDIAN
+ return be16_to_cpu(*(u16 *)(p+2));
+#else
+ return le16_to_cpu(*(u16 *)p);
+#endif
+}
+extern inline int isonum_731(char *p)
+{
+ return le32_to_cpu(*(u32 *)p);
+}
+extern inline int isonum_732(char *p)
+{
+ return be32_to_cpu(*(u32 *)p);
+}
+extern inline int isonum_733(char *p)
+{
+#ifdef __BIG_ENDIAN
+ return be32_to_cpu(*(u32 *)(p+4));
+#else
+ return le32_to_cpu(*(u32 *)p);
+#endif
+}
extern int iso_date(char *, int);

extern int parse_rock_ridge_inode(struct iso_directory_record *, struct inode *);
--- linux-2.4.4/fs/isofs/util.c Wed Nov 29 10:11:38 2000
+++ linux-2.4.4-ciso/fs/isofs/util.c Mon Apr 30 20:04:24 2001
@@ -1,90 +1,9 @@
/*
* linux/fs/isofs/util.c
- *
- * The special functions in the file are numbered according to the section
- * of the iso 9660 standard in which they are described. isonum_733 will
- * convert numbers according to section 7.3.3, etc.
- *
- * isofs special functions. This file was lifted in its entirety from
- * the 386BSD iso9660 filesystem, by Pace Willisson <pace@blitz.com>.
*/

#include <linux/time.h>
-
-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)
-{
-#if 0
- if (p[0] != p[3] || p[1] != p[2]) {
- fprintf (stderr, "invalid format 7.2.3 number\n");
- exit (1);
- }
-#endif
- 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)
-{
-#if 0
- int i;
-
- for (i = 0; i < 4; i++) {
- if (p[i] != p[7-i]) {
- fprintf (stderr, "bad format 7.3.3 number\n");
- exit (1);
- }
- }
-#endif
- return (isonum_731 (p));
-}
+#include <linux/iso_fs.h>

/*
* We have to convert from a MM/DD/YY format to the Unix ctime format.