--- /dev/null
+/*
+ * Copyright (c) 2008 Apple Inc. All rights reserved.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
+ *
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
+ */
+#ifndef _SYS_DECMPFS_H_
+#define _SYS_DECMPFS_H_ 1
+
+#define MAX_DECMPFS_XATTR_SIZE 3802
+
+/*
+ NOTE: decmpfs can only be used by thread-safe filesystems
+ */
+
+#define DECMPFS_MAGIC 0x636d7066 /* cmpf */
+
+#define DECMPFS_XATTR_NAME "com.apple.decmpfs" /* extended attribute to use for decmpfs */
+
+typedef struct __attribute__((packed)) {
+ /* this structure represents the xattr on disk; the fields below are little-endian */
+ uint32_t compression_magic;
+ uint32_t compression_type; /* see the enum below */
+ uint64_t uncompressed_size;
+ unsigned char attr_bytes[0]; /* the bytes of the attribute after the header */
+} decmpfs_disk_header;
+
+typedef struct __attribute__((packed)) {
+ /* this structure represents the xattr in memory; the fields below are host-endian */
+ uint32_t attr_size;
+ uint32_t compression_magic;
+ uint32_t compression_type;
+ uint64_t uncompressed_size;
+ unsigned char attr_bytes[0]; /* the bytes of the attribute after the header */
+} decmpfs_header;
+
+/* compression_type values */
+enum {
+ CMP_Type1 = 1, /* uncompressed data in xattr */
+
+ /* additional types defined in AppleFSCompression project */
+
+ CMP_MAX = 255
+};
+
+typedef struct {
+ void *buf;
+ user_ssize_t size;
+} decmpfs_vector;
+
+#if KERNEL
+
+#include <kern/locks.h>
+
+#if defined(__i386__) || defined(__x86_64__)
+#define DECMPFS_SUPPORTS_SWAP64 1
+/* otherwise, no OSCompareAndSwap64, so use a mutex */
+#endif
+
+typedef struct decmpfs_cnode {
+ uint8_t cmp_state;
+ uint8_t cmp_minimal_xattr; /* if non-zero, this file's com.apple.decmpfs xattr contained only the minimal decmpfs_disk_header */
+ uint32_t cmp_type;
+ uint32_t lockcount;
+ void *lockowner; /* cnode's lock owner (if a thread is currently holding an exclusive lock) */
+ uint64_t uncompressed_size;
+ lck_rw_t compressed_data_lock;
+#if !DECMPFS_SUPPORTS_SWAP64
+ /* we need a lock since we can't atomically fetch/set 64 bits */
+ lck_mtx_t uncompressed_size_mtx;
+#endif /* !DECMPFS_SUPPORTS_SWAP64 */
+} decmpfs_cnode;
+
+/* return values from decmpfs_file_is_compressed */
+enum {
+ FILE_TYPE_UNKNOWN = 0,
+ FILE_IS_NOT_COMPRESSED = 1,
+ FILE_IS_COMPRESSED = 2,
+ FILE_IS_CONVERTING = 3 /* file is converting from compressed to decompressed */
+};
+
+/* vfs entrypoints */
+extern vfs_context_t decmpfs_ctx;
+
+/* client filesystem entrypoints */
+void decmpfs_init(void);
+void decmpfs_cnode_init(decmpfs_cnode *cp);
+void decmpfs_cnode_destroy(decmpfs_cnode *cp);
+
+int decmpfs_hides_rsrc(vfs_context_t ctx, decmpfs_cnode *cp);
+int decmpfs_hides_xattr(vfs_context_t ctx, decmpfs_cnode *cp, const char *xattr);
+
+boolean_t decmpfs_trylock_compressed_data(decmpfs_cnode *cp, int exclusive);
+void decmpfs_lock_compressed_data(decmpfs_cnode *cp, int exclusive);
+void decmpfs_unlock_compressed_data(decmpfs_cnode *cp, int exclusive);
+
+uint32_t decmpfs_cnode_get_vnode_state(decmpfs_cnode *cp);
+void decmpfs_cnode_set_vnode_state(decmpfs_cnode *cp, uint32_t state, int skiplock);
+uint64_t decmpfs_cnode_get_vnode_cached_size(decmpfs_cnode *cp);
+
+int decmpfs_file_is_compressed(vnode_t vp, decmpfs_cnode *cp);
+errno_t decmpfs_validate_compressed_file(vnode_t vp, decmpfs_cnode *cp);
+int decmpfs_decompress_file(vnode_t vp, decmpfs_cnode *cp, off_t toSize, int truncate_okay, int skiplock); /* if toSize == -1, decompress the entire file */
+int decmpfs_free_compressed_data(vnode_t vp, decmpfs_cnode *cp);
+int decmpfs_update_attributes(vnode_t vp, struct vnode_attr *vap);
+/* the following two routines will set *is_compressed to 0 if the file was converted from compressed to decompressed before data could be fetched from the decompressor */
+errno_t decmpfs_pagein_compressed(struct vnop_pagein_args *ap, int *is_compressed, decmpfs_cnode *cp);
+errno_t decmpfs_read_compressed(struct vnop_read_args *ap, int *is_compressed, decmpfs_cnode *cp);
+
+/* types shared between the kernel and kexts */
+typedef int (*decmpfs_validate_compressed_file_func)(vnode_t vp, vfs_context_t ctx, decmpfs_header *hdr);
+typedef void (*decmpfs_adjust_fetch_region_func)(vnode_t vp, vfs_context_t ctx, decmpfs_header *hdr, off_t *offset, user_ssize_t *size);
+typedef int (*decmpfs_fetch_uncompressed_data_func)(vnode_t vp, vfs_context_t ctx, decmpfs_header *hdr, off_t offset, user_ssize_t size, int nvec, decmpfs_vector *vec, uint64_t *bytes_read);
+typedef int (*decmpfs_free_compressed_data_func)(vnode_t vp, vfs_context_t ctx, decmpfs_header *hdr);
+
+#define DECMPFS_REGISTRATION_VERSION 1
+typedef struct {
+ int decmpfs_registration;
+ decmpfs_validate_compressed_file_func validate;
+ decmpfs_adjust_fetch_region_func adjust_fetch;
+ decmpfs_fetch_uncompressed_data_func fetch;
+ decmpfs_free_compressed_data_func free_data;
+} decmpfs_registration;
+
+/* hooks for kexts to call */
+errno_t register_decmpfs_decompressor(uint32_t compression_type, decmpfs_registration *registration);
+errno_t unregister_decmpfs_decompressor(uint32_t compression_type, decmpfs_registration *registration);
+
+#endif /* KERNEL */
+
+#endif /* _SYS_DECMPFS_H_ */
projects / apple / xnu.git / blobdiff