darling-xnu/bsd/sys/decmpfs.h
2023-05-16 21:41:14 -07:00

274 lines
11 KiB
C

/*
* 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
#include <stdbool.h>
#include <sys/kdebug.h>
#include <sys/kernel_types.h>
#include <sys/vnode.h>
/*
* Please switch on @DECMPFS_ENABLE_KDEBUG_TRACES to enable tracepoints.
* Tracepoints are compiled out by default to eliminate any overhead due to
* kernel tracing.
*
* #define DECMPFS_ENABLE_KDEBUG_TRACES 1
*/
#if DECMPFS_ENABLE_KDEBUG_TRACES
#define DECMPFS_EMIT_TRACE_ENTRY(D, ...) \
KDBG_FILTERED((D) | DBG_FUNC_START, ## __VA_ARGS__)
#define DECMPFS_EMIT_TRACE_RETURN(D, ...) \
KDBG_FILTERED((D) | DBG_FUNC_END, ##__VA_ARGS__)
#else
#define DECMPFS_EMIT_TRACE_ENTRY(D, ...) do {} while (0)
#define DECMPFS_EMIT_TRACE_RETURN(D, ...) do {} while (0)
#endif /* DECMPFS_ENABLE_KDEBUG_TRACES */
/*
* KERNEL_DEBUG related definitions for decmpfs.
*
* Please NOTE: The Class DBG_FSYSTEM = 3, and Subclass DBG_DECMP = 0x12, so
* these debug codes are of the form 0x0312nnnn.
*/
#define DECMPDBG_CODE(code) FSDBG_CODE(DBG_DECMP, code)
enum {
DECMPDBG_DECOMPRESS_FILE = DECMPDBG_CODE(0),/* 0x03120000 */
DECMPDBG_FETCH_COMPRESSED_HEADER = DECMPDBG_CODE(1),/* 0x03120004 */
DECMPDBG_FETCH_UNCOMPRESSED_DATA = DECMPDBG_CODE(2),/* 0x03120008 */
DECMPDBG_FREE_COMPRESSED_DATA = DECMPDBG_CODE(4),/* 0x03120010 */
DECMPDBG_FILE_IS_COMPRESSED = DECMPDBG_CODE(5),/* 0x03120014 */
};
#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 */
/*
* This single field is to be interpreted differently depending on the
* corresponding item type.
* For regular files: it is a 64bits-encoded logical size
* For directories: it is a 64bits-encoded number of children (ie st_nlink - 2)
* For packages: it is 40bits encoded size and 24bits number of children at root
*/
typedef struct __attribute__((packed)) {
uint64_t value;
} decmpfs_raw_item_size;
#define DECMPFS_PKG_SIZE_MASK 0x000000ffffffffffULL
#define DECMPFS_PKG_COUNT_MASK 0xffffff
#define DECMPFS_PKG_CHLD_COUNT_SHIFT 40
#define DECMPFS_PKG_SIZE(x) ((x).value & DECMPFS_PKG_SIZE_MASK)
#define DECMPFS_PKG_CHLD_COUNT(x) ((uint32_t)(((x).value >> DECMPFS_PKG_CHLD_COUNT_SHIFT) & DECMPFS_PKG_COUNT_MASK))
#define DECMPFS_PKG_VALUE_FROM_SIZE_COUNT(size, count) \
(((size) & DECMPFS_PKG_SIZE_MASK) | ((uint64_t)(count) << DECMPFS_PKG_CHLD_COUNT_SHIFT))
/* Dataless file or directory */
#define DATALESS_CMPFS_TYPE 0x80000001
/* Dataless package, with number of root children and total size encoded on disk */
#define DATALESS_PKG_CMPFS_TYPE 0x80000002
static inline bool
decmpfs_type_is_dataless(uint32_t cmp_type)
{
return cmp_type == DATALESS_CMPFS_TYPE || cmp_type == DATALESS_PKG_CMPFS_TYPE;
}
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 */
union {
uint64_t uncompressed_size; /* compatility accessor */
decmpfs_raw_item_size _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;
union {
/*
* although uncompressed_size remains available for backward-compatibility reasons
* the uncompressed size and nchildren should be accessed using the inline helpers
* below
*/
uint64_t uncompressed_size;
decmpfs_raw_item_size _size;
};
unsigned char attr_bytes[0]; /* the bytes of the attribute after the header */
} decmpfs_header;
static inline uint64_t
decmpfs_get_uncompressed_size(const decmpfs_header *hdr)
{
if (hdr->compression_magic == DECMPFS_MAGIC && hdr->compression_type == DATALESS_PKG_CMPFS_TYPE) {
return DECMPFS_PKG_SIZE(hdr->_size);
}
return hdr->uncompressed_size;
}
static inline uint32_t
decmpfs_get_directory_entries(const decmpfs_header *hdr)
{
if (hdr->compression_magic == DECMPFS_MAGIC && hdr->compression_type == DATALESS_PKG_CMPFS_TYPE) {
return DECMPFS_PKG_CHLD_COUNT(hdr->_size);
}
return (uint32_t)hdr->uncompressed_size;
}
/* compression_type values */
enum {
CMP_Type1 = 1,/* uncompressed data in xattr */
/* additional types defined in AppleFSCompression project */
CMP_MAX = 255/* Highest compression_type supported */
};
typedef struct {
void *buf;
user_ssize_t size;
} decmpfs_vector;
#ifdef KERNEL
#ifdef XNU_KERNEL_PRIVATE
#include <kern/locks.h>
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 __attribute__((aligned(8)));
uint64_t nchildren __attribute__((aligned(8))); /* for dataless directories (incl. packages) */
uint64_t total_size __attribute__((aligned(8)));/* for dataless directories (incl. packages) */
uint64_t decompression_flags;
lck_rw_t compressed_data_lock;
};
#endif // XNU_KERNEL_PRIVATE
typedef struct decmpfs_cnode 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);
decmpfs_cnode *decmpfs_cnode_alloc(void);
void decmpfs_cnode_free(decmpfs_cnode *dp);
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);
bool 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);
uint64_t decmpfs_cnode_get_vnode_cached_nchildren(decmpfs_cnode *cp);
uint64_t decmpfs_cnode_get_vnode_cached_total_size(decmpfs_cnode *cp);
void decmpfs_cnode_set_vnode_cached_size(decmpfs_cnode *cp, uint64_t size);
void decmpfs_cnode_set_vnode_cached_nchildren(decmpfs_cnode *cp, uint64_t nchildren);
void decmpfs_cnode_set_vnode_cached_total_size(decmpfs_cnode *cp, uint64_t total_sz);
uint32_t decmpfs_cnode_cmp_type(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);
typedef uint64_t (*decmpfs_get_decompression_flags_func)(vnode_t vp, vfs_context_t ctx, decmpfs_header *hdr); // returns flags from the DECMPFS_FLAGS enumeration below
enum {
DECMPFS_FLAGS_FORCE_FLUSH_ON_DECOMPRESS = 1 << 0,
};
/* Versions that are supported for binary compatibility */
#define DECMPFS_REGISTRATION_VERSION_V1 1
#define DECMPFS_REGISTRATION_VERSION_V3 3
#define DECMPFS_REGISTRATION_VERSION (DECMPFS_REGISTRATION_VERSION_V3)
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_get_decompression_flags_func get_flags;
} decmpfs_registration;
/* hooks for kexts to call */
errno_t register_decmpfs_decompressor(uint32_t compression_type, const decmpfs_registration *registration);
errno_t unregister_decmpfs_decompressor(uint32_t compression_type, decmpfs_registration *registration);
#endif /* KERNEL */
#endif /* _SYS_DECMPFS_H_ */