1 files changed, 88 insertions, 0 deletions

diff --git a/include/uapi/linux/cramfs_fs.h b/include/uapi/linux/cramfs_fs.h
new file mode 100644
index 000000000000..e4611a9b9243
--- /dev/null
+++ b/include/uapi/linux/cramfs_fs.h
@@ -0,0 +1,88 @@
+#ifndef _UAPI__CRAMFS_H
+#define _UAPI__CRAMFS_H
+
+#include <linux/types.h>
+#include <linux/magic.h>
+
+#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 */
+
+/*
+ * 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 )
+
+
+#endif /* _UAPI__CRAMFS_H */