macos support

Makefile

@@ -4,7 +4,7 @@ all: cramfsswap strip
 debian: cramfsswap
 
 cramfsswap: cramfsswap.c
-	gcc -Wall -g -O -o cramfsswap -lz cramfsswap.c
+	gcc -std=c89 -Wall -g -O -o cramfsswap -lz cramfsswap.c
 
 strip:
 	strip cramfsswap

cramfsswap.c

@@ -11,8 +11,7 @@
 #include <stdio.h>
 #include <inttypes.h>
 #include <sys/stat.h>
-#include <linux/cramfs_fs.h>
-#include <byteswap.h>
+#include "linux/cramfs_fs.h"
 #include <zlib.h> /* for crc32 */
 #include <sys/mman.h>
 #include <fcntl.h>
@@ -23,6 +22,17 @@
 #define MAXFILES	4096
 #define BLKSIZE		4096	/* Should this be a command line option? */
 
+#define bswap_16(value) \
+((((value) & 0xff) << 8) | ((value) >> 8))
+
+#define bswap_32(value) \
+(((uint32_t)bswap_16((uint16_t)((value) & 0xffff)) << 16) | \
+(uint32_t)bswap_16((uint16_t)((value) >> 16)))
+
+#define bswap_64(value) \
+(((uint64_t)bswap_32((uint32_t)((value) & 0xffffffff)) \
+<< 32) | \
+(uint64_t)bswap_32((uint32_t)((value) >> 32)))
 
 int main(int argc, char *argv[])
 {

linux/cramfs_fs.h

@@ -0,0 +1,118 @@
+#ifndef __CRAMFS_H
+#define __CRAMFS_H
+
+#ifndef __KERNEL__
+
+typedef unsigned char u8;
+typedef unsigned short u16;
+typedef unsigned int u32;
+
+#endif
+
+#define CRAMFS_MAGIC		0x28cd3d45	/* some random number */
+#define CRAMFS_SIGNATURE	"Compressed ROMFS"
+
+/*
+ * Width of various bitfields in struct cramfs_inode.
+ * Primarily used to generate warnings in mkcramfs.
+ */
+#define CRAMFS_MODE_WIDTH 16
+#define CRAMFS_UID_WIDTH 16
+#define CRAMFS_SIZE_WIDTH 24
+#define CRAMFS_GID_WIDTH 8
+#define CRAMFS_NAMELEN_WIDTH 6
+#define CRAMFS_OFFSET_WIDTH 26
+
+/*
+ * Since inode.namelen is a unsigned 6-bit number, the maximum cramfs
+ * path length is 63 << 2 = 252.
+ */
+#define CRAMFS_MAXPATHLEN (((1 << CRAMFS_NAMELEN_WIDTH) - 1) << 2)
+
+/*
+ * Reasonably terse representation of the inode data.
+ */
+struct cramfs_inode {
+	u32 mode:CRAMFS_MODE_WIDTH, uid:CRAMFS_UID_WIDTH;
+	/* SIZE for device files is i_rdev */
+	u32 size:CRAMFS_SIZE_WIDTH, gid:CRAMFS_GID_WIDTH;
+	/* NAMELEN is the length of the file name, divided by 4 and
+           rounded up.  (cramfs doesn't support hard links.) */
+	/* OFFSET: For symlinks and non-empty regular files, this
+	   contains the offset (divided by 4) of the file data in
+	   compressed form (starting with an array of block pointers;
+	   see README).  For non-empty directories it is the offset
+	   (divided by 4) of the inode of the first file in that
+	   directory.  For anything else, offset is zero. */
+	u32 namelen:CRAMFS_NAMELEN_WIDTH, offset:CRAMFS_OFFSET_WIDTH;
+};
+
+struct cramfs_info {
+	u32 crc;
+	u32 edition;
+	u32 blocks;
+	u32 files;
+};
+
+/*
+ * Superblock information at the beginning of the FS.
+ */
+struct cramfs_super {
+	u32 magic;			/* 0x28cd3d45 - random number */
+	u32 size;			/* length in bytes */
+	u32 flags;			/* feature flags */
+	u32 future;			/* reserved for future use */
+	u8 signature[16];		/* "Compressed ROMFS" */
+	struct cramfs_info fsid;	/* unique filesystem info */
+	u8 name[16];			/* user-defined name */
+	struct cramfs_inode root;	/* root inode data */
+};
+
+/*
+ * Feature flags
+ *
+ * 0x00000000 - 0x000000ff: features that work for all past kernels
+ * 0x00000100 - 0xffffffff: features that don't work for past kernels
+ */
+#define CRAMFS_FLAG_FSID_VERSION_2	0x00000001	/* fsid version #2 */
+#define CRAMFS_FLAG_SORTED_DIRS		0x00000002	/* sorted dirs */
+#define CRAMFS_FLAG_HOLES		0x00000100	/* support for holes */
+#define CRAMFS_FLAG_WRONG_SIGNATURE	0x00000200	/* reserved */
+#define CRAMFS_FLAG_SHIFTED_ROOT_OFFSET	0x00000400	/* shifted root fs */
+#define CRAMFS_FLAG_EXT_BLOCK_POINTERS	0x00000800	/* block pointer extensions */
+
+/*
+ * Valid values in super.flags.  Currently we refuse to mount
+ * if (flags & ~CRAMFS_SUPPORTED_FLAGS).  Maybe that should be
+ * changed to test super.future instead.
+ */
+#define CRAMFS_SUPPORTED_FLAGS	( 0x000000ff \
+				| CRAMFS_FLAG_HOLES \
+				| CRAMFS_FLAG_WRONG_SIGNATURE \
+				| CRAMFS_FLAG_SHIFTED_ROOT_OFFSET \
+				| CRAMFS_FLAG_EXT_BLOCK_POINTERS )
+
+/*
+ * Block pointer flags
+ *
+ * The maximum block offset that needs to be represented is roughly:
+ *
+ *   (1 << CRAMFS_OFFSET_WIDTH) * 4 +
+ *   (1 << CRAMFS_SIZE_WIDTH) / PAGE_SIZE * (4 + PAGE_SIZE)
+ *   = 0x11004000
+ *
+ * That leaves room for 3 flag bits in the block pointer table.
+ */
+#define CRAMFS_BLK_FLAG_UNCOMPRESSED	(1 << 31)
+#define CRAMFS_BLK_FLAG_DIRECT_PTR	(1 << 30)
+
+#define CRAMFS_BLK_FLAGS	( CRAMFS_BLK_FLAG_UNCOMPRESSED \
+				| CRAMFS_BLK_FLAG_DIRECT_PTR )
+
+/*
+ * Direct blocks are at least 4-byte aligned.
+ * Pointers to direct blocks are shifted down by 2 bits.
+ */
+#define CRAMFS_BLK_DIRECT_PTR_SHIFT	2
+
+#endif