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gems-kernel/source/THIRDPARTY/xnu/bsd/kern/decmpfs.c
Sam Sneed f5727805f2 add darwin/xnu functionality
2024-06-03 11:29:39 -05:00

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/*
* Copyright (c) 2008-2018 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@
*/
#if !FS_COMPRESSION
/* We need these symbols even though compression is turned off */
#define UNUSED_SYMBOL(x) asm(".global _" #x "\n.set _" #x ", 0\n");
UNUSED_SYMBOL(register_decmpfs_decompressor)
UNUSED_SYMBOL(unregister_decmpfs_decompressor)
UNUSED_SYMBOL(decmpfs_init)
UNUSED_SYMBOL(decmpfs_read_compressed)
UNUSED_SYMBOL(decmpfs_cnode_cmp_type)
UNUSED_SYMBOL(decmpfs_cnode_get_vnode_state)
UNUSED_SYMBOL(decmpfs_cnode_get_vnode_cached_size)
UNUSED_SYMBOL(decmpfs_cnode_get_vnode_cached_nchildren)
UNUSED_SYMBOL(decmpfs_cnode_get_vnode_cached_total_size)
UNUSED_SYMBOL(decmpfs_lock_compressed_data)
UNUSED_SYMBOL(decmpfs_cnode_free)
UNUSED_SYMBOL(decmpfs_cnode_alloc)
UNUSED_SYMBOL(decmpfs_cnode_destroy)
UNUSED_SYMBOL(decmpfs_decompress_file)
UNUSED_SYMBOL(decmpfs_unlock_compressed_data)
UNUSED_SYMBOL(decmpfs_cnode_init)
UNUSED_SYMBOL(decmpfs_cnode_set_vnode_state)
UNUSED_SYMBOL(decmpfs_hides_xattr)
UNUSED_SYMBOL(decmpfs_ctx)
UNUSED_SYMBOL(decmpfs_file_is_compressed)
UNUSED_SYMBOL(decmpfs_update_attributes)
UNUSED_SYMBOL(decmpfs_hides_rsrc)
UNUSED_SYMBOL(decmpfs_pagein_compressed)
UNUSED_SYMBOL(decmpfs_validate_compressed_file)
#else /* FS_COMPRESSION */
#include <sys/kernel.h>
#include <sys/vnode_internal.h>
#include <sys/file_internal.h>
#include <sys/stat.h>
#include <sys/fcntl.h>
#include <sys/xattr.h>
#include <sys/namei.h>
#include <sys/user.h>
#include <sys/mount_internal.h>
#include <sys/ubc.h>
#include <sys/decmpfs.h>
#include <sys/uio_internal.h>
#include <libkern/OSByteOrder.h>
#include <libkern/section_keywords.h>
#include <sys/fsctl.h>
#include <sys/kdebug_triage.h>
#include <ptrauth.h>
#pragma mark --- debugging ---
#define COMPRESSION_DEBUG 0
#define COMPRESSION_DEBUG_VERBOSE 0
#define MALLOC_DEBUG 0
#if COMPRESSION_DEBUG
static char*
vnpath(vnode_t vp, char *path, int len)
{
int origlen = len;
path[0] = 0;
vn_getpath(vp, path, &len);
path[origlen - 1] = 0;
return path;
}
#endif
#define ErrorLog(x, args...) \
printf("%s:%d:%s: " x, __FILE_NAME__, __LINE__, __FUNCTION__, ## args)
#if COMPRESSION_DEBUG
#define ErrorLogWithPath(x, args...) do { \
char *path = zalloc(ZV_NAMEI); \
printf("%s:%d:%s: %s: " x, __FILE_NAME__, __LINE__, __FUNCTION__, \
vnpath(vp, path, PATH_MAX), ## args); \
zfree(ZV_NAMEI, path); \
} while(0)
#else
#define ErrorLogWithPath(x, args...) do { \
(void*)vp; \
printf("%s:%d:%s: %s: " x, __FILE_NAME__, __LINE__, __FUNCTION__, \
"<private>", ## args); \
} while(0)
#endif
#if COMPRESSION_DEBUG
#define DebugLog ErrorLog
#define DebugLogWithPath ErrorLogWithPath
#else
#define DebugLog(x...) do { } while(0)
#define DebugLogWithPath(x...) do { } while(0)
#endif
#if COMPRESSION_DEBUG_VERBOSE
#define VerboseLog ErrorLog
#define VerboseLogWithPath ErrorLogWithPath
#else
#define VerboseLog(x...) do { } while(0)
#define VerboseLogWithPath(x...) do { } while(0)
#endif
#define decmpfs_ktriage_record(code, arg) ktriage_record(thread_tid(current_thread()), KDBG_TRIAGE_EVENTID(KDBG_TRIAGE_SUBSYS_DECMPFS, KDBG_TRIAGE_RESERVED, code), arg);
enum ktriage_decmpfs_error_codes {
KTRIAGE_DECMPFS_PREFIX = 0,
KTRIAGE_DECMPFS_IVALID_OFFSET,
KTRIAGE_DECMPFS_COMPRESSOR_NOT_REGISTERED,
KTRIAGE_DECMPFS_FETCH_CALLBACK_FAILED,
KTRIAGE_DECMPFS_FETCH_HEADER_FAILED,
KTRIAGE_DECMPFS_UBC_UPL_MAP_FAILED,
KTRIAGE_DECMPFS_FETCH_UNCOMPRESSED_DATA_FAILED,
KTRIAGE_DECMPFS_MAX
};
const char *ktriage_decmpfs_strings[] = {
[KTRIAGE_DECMPFS_PREFIX] = "decmpfs - ",
[KTRIAGE_DECMPFS_IVALID_OFFSET] = "pagein offset is invalid\n",
[KTRIAGE_DECMPFS_COMPRESSOR_NOT_REGISTERED] = "compressor is not registered\n",
[KTRIAGE_DECMPFS_FETCH_CALLBACK_FAILED] = "fetch callback failed\n",
[KTRIAGE_DECMPFS_FETCH_HEADER_FAILED] = "fetch decmpfs xattr failed\n",
[KTRIAGE_DECMPFS_UBC_UPL_MAP_FAILED] = "failed to map a UBC UPL\n",
[KTRIAGE_DECMPFS_FETCH_UNCOMPRESSED_DATA_FAILED] = "failed to fetch uncompressed data\n",
};
ktriage_strings_t ktriage_decmpfs_subsystem_strings = {KTRIAGE_DECMPFS_MAX, ktriage_decmpfs_strings};
#pragma mark --- globals ---
static LCK_GRP_DECLARE(decmpfs_lockgrp, "VFSCOMP");
static LCK_RW_DECLARE(decompressorsLock, &decmpfs_lockgrp);
static LCK_MTX_DECLARE(decompress_channel_mtx, &decmpfs_lockgrp);
static const decmpfs_registration *decompressors[CMP_MAX]; /* the registered compressors */
static int decompress_channel; /* channel used by decompress_file to wake up waiters */
vfs_context_t decmpfs_ctx;
#pragma mark --- decmp_get_func ---
#define offsetof_func(func) ((uintptr_t)offsetof(decmpfs_registration, func))
static void *
_func_from_offset(uint32_t type, uintptr_t offset, uint32_t discriminator)
{
/* get the function at the given offset in the registration for the given type */
const decmpfs_registration *reg = decompressors[type];
switch (reg->decmpfs_registration) {
case DECMPFS_REGISTRATION_VERSION_V1:
if (offset > offsetof_func(free_data)) {
return NULL;
}
break;
case DECMPFS_REGISTRATION_VERSION_V3:
if (offset > offsetof_func(get_flags)) {
return NULL;
}
break;
default:
return NULL;
}
void *ptr = *(void * const *)((uintptr_t)reg + offset);
if (ptr != NULL) {
/* Resign as a function-in-void* */
ptr = ptrauth_auth_and_resign(ptr, ptrauth_key_asia, discriminator, ptrauth_key_asia, 0);
}
return ptr;
}
extern void IOServicePublishResource( const char * property, boolean_t value );
extern boolean_t IOServiceWaitForMatchingResource( const char * property, uint64_t timeout );
extern boolean_t IOCatalogueMatchingDriversPresent( const char * property );
static void *
_decmp_get_func(vnode_t vp, uint32_t type, uintptr_t offset, uint32_t discriminator)
{
/*
* this function should be called while holding a shared lock to decompressorsLock,
* and will return with the lock held
*/
if (type >= CMP_MAX) {
return NULL;
}
if (decompressors[type] != NULL) {
// the compressor has already registered but the function might be null
return _func_from_offset(type, offset, discriminator);
}
// does IOKit know about a kext that is supposed to provide this type?
char providesName[80];
snprintf(providesName, sizeof(providesName), "com.apple.AppleFSCompression.providesType%u", type);
if (IOCatalogueMatchingDriversPresent(providesName)) {
// there is a kext that says it will register for this type, so let's wait for it
char resourceName[80];
uint64_t delay = 10000000ULL; // 10 milliseconds.
snprintf(resourceName, sizeof(resourceName), "com.apple.AppleFSCompression.Type%u", type);
ErrorLogWithPath("waiting for %s\n", resourceName);
while (decompressors[type] == NULL) {
lck_rw_unlock_shared(&decompressorsLock); // we have to unlock to allow the kext to register
if (IOServiceWaitForMatchingResource(resourceName, delay)) {
lck_rw_lock_shared(&decompressorsLock);
break;
}
if (!IOCatalogueMatchingDriversPresent(providesName)) {
//
ErrorLogWithPath("the kext with %s is no longer present\n", providesName);
lck_rw_lock_shared(&decompressorsLock);
break;
}
ErrorLogWithPath("still waiting for %s\n", resourceName);
delay *= 2;
lck_rw_lock_shared(&decompressorsLock);
}
// IOKit says the kext is loaded, so it should be registered too!
if (decompressors[type] == NULL) {
ErrorLogWithPath("we found %s, but the type still isn't registered\n", providesName);
return NULL;
}
// it's now registered, so let's return the function
return _func_from_offset(type, offset, discriminator);
}
// the compressor hasn't registered, so it never will unless someone manually kextloads it
ErrorLogWithPath("tried to access a compressed file of unregistered type %d\n", type);
return NULL;
}
#define decmp_get_func(vp, type, func) (typeof(decompressors[0]->func))_decmp_get_func(vp, type, offsetof_func(func), ptrauth_function_pointer_type_discriminator(typeof(decompressors[0]->func)))
#pragma mark --- utilities ---
#if COMPRESSION_DEBUG
static int
vnsize(vnode_t vp, uint64_t *size)
{
struct vnode_attr va;
VATTR_INIT(&va);
VATTR_WANTED(&va, va_data_size);
int error = vnode_getattr(vp, &va, decmpfs_ctx);
if (error != 0) {
ErrorLogWithPath("vnode_getattr err %d\n", error);
return error;
}
*size = va.va_data_size;
return 0;
}
#endif /* COMPRESSION_DEBUG */
#pragma mark --- cnode routines ---
ZONE_DEFINE(decmpfs_cnode_zone, "decmpfs_cnode",
sizeof(struct decmpfs_cnode), ZC_NONE);
decmpfs_cnode *
decmpfs_cnode_alloc(void)
{
return zalloc(decmpfs_cnode_zone);
}
void
decmpfs_cnode_free(decmpfs_cnode *dp)
{
zfree(decmpfs_cnode_zone, dp);
}
void
decmpfs_cnode_init(decmpfs_cnode *cp)
{
memset(cp, 0, sizeof(*cp));
lck_rw_init(&cp->compressed_data_lock, &decmpfs_lockgrp, NULL);
}
void
decmpfs_cnode_destroy(decmpfs_cnode *cp)
{
lck_rw_destroy(&cp->compressed_data_lock, &decmpfs_lockgrp);
}
bool
decmpfs_trylock_compressed_data(decmpfs_cnode *cp, int exclusive)
{
void *thread = current_thread();
bool retval = false;
if (cp->lockowner == thread) {
/* this thread is already holding an exclusive lock, so bump the count */
cp->lockcount++;
retval = true;
} else if (exclusive) {
if ((retval = lck_rw_try_lock_exclusive(&cp->compressed_data_lock))) {
cp->lockowner = thread;
cp->lockcount = 1;
}
} else {
if ((retval = lck_rw_try_lock_shared(&cp->compressed_data_lock))) {
cp->lockowner = (void *)-1;
}
}
return retval;
}
void
decmpfs_lock_compressed_data(decmpfs_cnode *cp, int exclusive)
{
void *thread = current_thread();
if (cp->lockowner == thread) {
/* this thread is already holding an exclusive lock, so bump the count */
cp->lockcount++;
} else if (exclusive) {
lck_rw_lock_exclusive(&cp->compressed_data_lock);
cp->lockowner = thread;
cp->lockcount = 1;
} else {
lck_rw_lock_shared(&cp->compressed_data_lock);
cp->lockowner = (void *)-1;
}
}
void
decmpfs_unlock_compressed_data(decmpfs_cnode *cp, __unused int exclusive)
{
void *thread = current_thread();
if (cp->lockowner == thread) {
/* this thread is holding an exclusive lock, so decrement the count */
if ((--cp->lockcount) > 0) {
/* the caller still has outstanding locks, so we're done */
return;
}
cp->lockowner = NULL;
}
lck_rw_done(&cp->compressed_data_lock);
}
uint32_t
decmpfs_cnode_get_vnode_state(decmpfs_cnode *cp)
{
return cp->cmp_state;
}
void
decmpfs_cnode_set_vnode_state(decmpfs_cnode *cp, uint32_t state, int skiplock)
{
if (!skiplock) {
decmpfs_lock_compressed_data(cp, 1);
}
cp->cmp_state = (uint8_t)state;
if (state == FILE_TYPE_UNKNOWN) {
/* clear out the compression type too */
cp->cmp_type = 0;
}
if (!skiplock) {
decmpfs_unlock_compressed_data(cp, 1);
}
}
static void
decmpfs_cnode_set_vnode_cmp_type(decmpfs_cnode *cp, uint32_t cmp_type, int skiplock)
{
if (!skiplock) {
decmpfs_lock_compressed_data(cp, 1);
}
cp->cmp_type = cmp_type;
if (!skiplock) {
decmpfs_unlock_compressed_data(cp, 1);
}
}
static void
decmpfs_cnode_set_vnode_minimal_xattr(decmpfs_cnode *cp, int minimal_xattr, int skiplock)
{
if (!skiplock) {
decmpfs_lock_compressed_data(cp, 1);
}
cp->cmp_minimal_xattr = !!minimal_xattr;
if (!skiplock) {
decmpfs_unlock_compressed_data(cp, 1);
}
}
uint64_t
decmpfs_cnode_get_vnode_cached_size(decmpfs_cnode *cp)
{
return cp->uncompressed_size;
}
uint64_t
decmpfs_cnode_get_vnode_cached_nchildren(decmpfs_cnode *cp)
{
return cp->nchildren;
}
uint64_t
decmpfs_cnode_get_vnode_cached_total_size(decmpfs_cnode *cp)
{
return cp->total_size;
}
void
decmpfs_cnode_set_vnode_cached_size(decmpfs_cnode *cp, uint64_t size)
{
while (1) {
uint64_t old = cp->uncompressed_size;
if (OSCompareAndSwap64(old, size, (UInt64*)&cp->uncompressed_size)) {
return;
} else {
/* failed to write our value, so loop */
}
}
}
void
decmpfs_cnode_set_vnode_cached_nchildren(decmpfs_cnode *cp, uint64_t nchildren)
{
while (1) {
uint64_t old = cp->nchildren;
if (OSCompareAndSwap64(old, nchildren, (UInt64*)&cp->nchildren)) {
return;
} else {
/* failed to write our value, so loop */
}
}
}
void
decmpfs_cnode_set_vnode_cached_total_size(decmpfs_cnode *cp, uint64_t total_sz)
{
while (1) {
uint64_t old = cp->total_size;
if (OSCompareAndSwap64(old, total_sz, (UInt64*)&cp->total_size)) {
return;
} else {
/* failed to write our value, so loop */
}
}
}
static uint64_t
decmpfs_cnode_get_decompression_flags(decmpfs_cnode *cp)
{
return cp->decompression_flags;
}
static void
decmpfs_cnode_set_decompression_flags(decmpfs_cnode *cp, uint64_t flags)
{
while (1) {
uint64_t old = cp->decompression_flags;
if (OSCompareAndSwap64(old, flags, (UInt64*)&cp->decompression_flags)) {
return;
} else {
/* failed to write our value, so loop */
}
}
}
uint32_t
decmpfs_cnode_cmp_type(decmpfs_cnode *cp)
{
return cp->cmp_type;
}
#pragma mark --- decmpfs state routines ---
static int
decmpfs_fetch_compressed_header(vnode_t vp, decmpfs_cnode *cp, decmpfs_header **hdrOut, int returnInvalid, size_t *hdr_size)
{
/*
* fetches vp's compression xattr, converting it into a decmpfs_header; returns 0 or errno
* if returnInvalid == 1, returns the header even if the type was invalid (out of range),
* and return ERANGE in that case
*/
size_t read_size = 0;
size_t attr_size = 0;
size_t alloc_size = 0;
uio_t attr_uio = NULL;
int err = 0;
char *data = NULL;
const bool no_additional_data = ((cp != NULL)
&& (cp->cmp_type != 0)
&& (cp->cmp_minimal_xattr != 0));
UIO_STACKBUF(uio_buf, 1);
decmpfs_header *hdr = NULL;
/*
* Trace the following parameters on entry with event-id 0x03120004
*
* @vp->v_id: vnode-id for which to fetch compressed header.
* @no_additional_data: If set true then xattr didn't have any extra data.
* @returnInvalid: return the header even though the type is out of range.
*/
DECMPFS_EMIT_TRACE_ENTRY(DECMPDBG_FETCH_COMPRESSED_HEADER, vp->v_id,
no_additional_data, returnInvalid);
if (no_additional_data) {
/* this file's xattr didn't have any extra data when we fetched it, so we can synthesize a header from the data in the cnode */
alloc_size = sizeof(decmpfs_header);
data = kalloc_data(sizeof(decmpfs_header), Z_WAITOK);
if (!data) {
err = ENOMEM;
goto out;
}
hdr = (decmpfs_header*)data;
hdr->attr_size = sizeof(decmpfs_disk_header);
hdr->compression_magic = DECMPFS_MAGIC;
hdr->compression_type = cp->cmp_type;
if (hdr->compression_type == DATALESS_PKG_CMPFS_TYPE) {
if (!vnode_isdir(vp)) {
err = EINVAL;
goto out;
}
hdr->_size.value = DECMPFS_PKG_VALUE_FROM_SIZE_COUNT(
decmpfs_cnode_get_vnode_cached_size(cp),
decmpfs_cnode_get_vnode_cached_nchildren(cp));
} else if (vnode_isdir(vp)) {
hdr->_size.value = decmpfs_cnode_get_vnode_cached_nchildren(cp);
} else {
hdr->_size.value = decmpfs_cnode_get_vnode_cached_size(cp);
}
} else {
/* figure out how big the xattr is on disk */
err = vn_getxattr(vp, DECMPFS_XATTR_NAME, NULL, &attr_size, XATTR_NOSECURITY, decmpfs_ctx);
if (err != 0) {
goto out;
}
alloc_size = attr_size + sizeof(hdr->attr_size);
if (attr_size < sizeof(decmpfs_disk_header) || attr_size > MAX_DECMPFS_XATTR_SIZE) {
err = EINVAL;
goto out;
}
/* allocation includes space for the extra attr_size field of a compressed_header */
data = (char *)kalloc_data(alloc_size, Z_WAITOK);
if (!data) {
err = ENOMEM;
goto out;
}
/* read the xattr into our buffer, skipping over the attr_size field at the beginning */
attr_uio = uio_createwithbuffer(1, 0, UIO_SYSSPACE, UIO_READ, &uio_buf[0], sizeof(uio_buf));
uio_addiov(attr_uio, CAST_USER_ADDR_T(data + sizeof(hdr->attr_size)), attr_size);
err = vn_getxattr(vp, DECMPFS_XATTR_NAME, attr_uio, &read_size, XATTR_NOSECURITY, decmpfs_ctx);
if (err != 0) {
goto out;
}
if (read_size != attr_size) {
err = EINVAL;
goto out;
}
hdr = (decmpfs_header*)data;
hdr->attr_size = (uint32_t)attr_size;
/* swap the fields to native endian */
hdr->compression_magic = OSSwapLittleToHostInt32(hdr->compression_magic);
hdr->compression_type = OSSwapLittleToHostInt32(hdr->compression_type);
hdr->uncompressed_size = OSSwapLittleToHostInt64(hdr->uncompressed_size);
}
if (hdr->compression_magic != DECMPFS_MAGIC) {
ErrorLogWithPath("invalid compression_magic 0x%08x, should be 0x%08x\n", hdr->compression_magic, DECMPFS_MAGIC);
err = EINVAL;
goto out;
}
/*
* Special-case the DATALESS compressor here; that is a valid type,
* even through there will never be an entry in the decompressor
* handler table for it. If we don't do this, then the cmp_state
* for this cnode will end up being marked NOT_COMPRESSED, and
* we'll be stuck in limbo.
*/
if (hdr->compression_type >= CMP_MAX && !decmpfs_type_is_dataless(hdr->compression_type)) {
if (returnInvalid) {
/* return the header even though the type is out of range */
err = ERANGE;
} else {
ErrorLogWithPath("compression_type %d out of range\n", hdr->compression_type);
err = EINVAL;
}
goto out;
}
out:
if (err && (err != ERANGE)) {
DebugLogWithPath("err %d\n", err);
kfree_data(data, alloc_size);
*hdrOut = NULL;
} else {
*hdrOut = hdr;
*hdr_size = alloc_size;
}
/*
* Trace the following parameters on return with event-id 0x03120004.
*
* @vp->v_id: vnode-id for which to fetch compressed header.
* @err: value returned from this function.
*/
DECMPFS_EMIT_TRACE_RETURN(DECMPDBG_FETCH_COMPRESSED_HEADER, vp->v_id, err);
return err;
}
static int
decmpfs_fast_get_state(decmpfs_cnode *cp)
{
/*
* return the cached state
* this should *only* be called when we know that decmpfs_file_is_compressed has already been called,
* because this implies that the cached state is valid
*/
int cmp_state = decmpfs_cnode_get_vnode_state(cp);
switch (cmp_state) {
case FILE_IS_NOT_COMPRESSED:
case FILE_IS_COMPRESSED:
case FILE_IS_CONVERTING:
return cmp_state;
case FILE_TYPE_UNKNOWN:
/*
* we should only get here if decmpfs_file_is_compressed was not called earlier on this vnode,
* which should not be possible
*/
ErrorLog("decmpfs_fast_get_state called on unknown file\n");
return FILE_IS_NOT_COMPRESSED;
default:
/* */
ErrorLog("unknown cmp_state %d\n", cmp_state);
return FILE_IS_NOT_COMPRESSED;
}
}
static int
decmpfs_fast_file_is_compressed(decmpfs_cnode *cp)
{
int cmp_state = decmpfs_cnode_get_vnode_state(cp);
switch (cmp_state) {
case FILE_IS_NOT_COMPRESSED:
return 0;
case FILE_IS_COMPRESSED:
case FILE_IS_CONVERTING:
return 1;
case FILE_TYPE_UNKNOWN:
/*
* we should only get here if decmpfs_file_is_compressed was not called earlier on this vnode,
* which should not be possible
*/
ErrorLog("decmpfs_fast_get_state called on unknown file\n");
return 0;
default:
/* */
ErrorLog("unknown cmp_state %d\n", cmp_state);
return 0;
}
}
errno_t
decmpfs_validate_compressed_file(vnode_t vp, decmpfs_cnode *cp)
{
/* give a compressor a chance to indicate that a compressed file is invalid */
decmpfs_header *hdr = NULL;
size_t alloc_size = 0;
errno_t err = decmpfs_fetch_compressed_header(vp, cp, &hdr, 0, &alloc_size);
if (err) {
/* we couldn't get the header */
if (decmpfs_fast_get_state(cp) == FILE_IS_NOT_COMPRESSED) {
/* the file is no longer compressed, so return success */
err = 0;
}
goto out;
}
if (!decmpfs_type_is_dataless(hdr->compression_type)) {
lck_rw_lock_shared(&decompressorsLock);
decmpfs_validate_compressed_file_func validate = decmp_get_func(vp, hdr->compression_type, validate);
if (validate) { /* make sure this validation function is valid */
/* is the data okay? */
err = validate(vp, decmpfs_ctx, hdr);
} else if (decmp_get_func(vp, hdr->compression_type, fetch) == NULL) {
/* the type isn't registered */
err = EIO;
} else {
/* no validate registered, so nothing to do */
err = 0;
}
lck_rw_unlock_shared(&decompressorsLock);
}
out:
if (hdr != NULL) {
kfree_data(hdr, alloc_size);
}
#if COMPRESSION_DEBUG
if (err) {
DebugLogWithPath("decmpfs_validate_compressed_file ret %d, vp->v_flag %d\n", err, vp->v_flag);
}
#endif
return err;
}
int
decmpfs_file_is_compressed(vnode_t vp, decmpfs_cnode *cp)
{
/*
* determines whether vp points to a compressed file
*
* to speed up this operation, we cache the result in the cnode, and do as little as possible
* in the case where the cnode already has a valid cached state
*
*/
int ret = 0;
int error = 0;
uint32_t cmp_state;
struct vnode_attr va_fetch;
decmpfs_header *hdr = NULL;
size_t alloc_size = 0;
mount_t mp = NULL;
int cnode_locked = 0;
int saveInvalid = 0; // save the header data even though the type was out of range
uint64_t decompression_flags = 0;
bool is_mounted, is_local_fs;
if (vnode_isnamedstream(vp)) {
/*
* named streams can't be compressed
* since named streams of the same file share the same cnode,
* we don't want to get/set the state in the cnode, just return 0
*/
return 0;
}
/* examine the cached a state in this cnode */
cmp_state = decmpfs_cnode_get_vnode_state(cp);
switch (cmp_state) {
case FILE_IS_NOT_COMPRESSED:
return 0;
case FILE_IS_COMPRESSED:
return 1;
case FILE_IS_CONVERTING:
/* treat the file as compressed, because this gives us a way to block future reads until decompression is done */
return 1;
case FILE_TYPE_UNKNOWN:
/* the first time we encountered this vnode, so we need to check it out */
break;
default:
/* unknown state, assume file is not compressed */
ErrorLogWithPath("unknown cmp_state %d\n", cmp_state);
return 0;
}
is_mounted = false;
is_local_fs = false;
mp = vnode_mount(vp);
if (mp) {
is_mounted = true;
}
if (is_mounted) {
is_local_fs = ((mp->mnt_flag & MNT_LOCAL));
}
/*
* Trace the following parameters on entry with event-id 0x03120014.
*
* @vp->v_id: vnode-id of the file being queried.
* @is_mounted: set to true if @vp belongs to a mounted fs.
* @is_local_fs: set to true if @vp belongs to local fs.
*/
DECMPFS_EMIT_TRACE_ENTRY(DECMPDBG_FILE_IS_COMPRESSED, vp->v_id,
is_mounted, is_local_fs);
if (!is_mounted) {
/*
* this should only be true before we mount the root filesystem
* we short-cut this return to avoid the call to getattr below, which
* will fail before root is mounted
*/
ret = FILE_IS_NOT_COMPRESSED;
goto done;
}
if (!is_local_fs) {
/* compression only supported on local filesystems */
ret = FILE_IS_NOT_COMPRESSED;
goto done;
}
/* lock our cnode data so that another caller doesn't change the state under us */
decmpfs_lock_compressed_data(cp, 1);
cnode_locked = 1;
VATTR_INIT(&va_fetch);
VATTR_WANTED(&va_fetch, va_flags);
error = vnode_getattr(vp, &va_fetch, decmpfs_ctx);
if (error) {
/* failed to get the bsd flags so the file is not compressed */
ret = FILE_IS_NOT_COMPRESSED;
goto done;
}
if (va_fetch.va_flags & UF_COMPRESSED) {
/* UF_COMPRESSED is on, make sure the file has the DECMPFS_XATTR_NAME xattr */
error = decmpfs_fetch_compressed_header(vp, cp, &hdr, 1, &alloc_size);
if ((hdr != NULL) && (error == ERANGE)) {
saveInvalid = 1;
}
if (error) {
/* failed to get the xattr so the file is not compressed */
ret = FILE_IS_NOT_COMPRESSED;
goto done;
}
/*
* We got the xattr, so the file is at least tagged compressed.
* For DATALESS, regular files and directories can be "compressed".
* For all other types, only files are allowed.
*/
if (!vnode_isreg(vp) &&
!(decmpfs_type_is_dataless(hdr->compression_type) && vnode_isdir(vp))) {
ret = FILE_IS_NOT_COMPRESSED;
goto done;
}
ret = FILE_IS_COMPRESSED;
goto done;
}
/* UF_COMPRESSED isn't on, so the file isn't compressed */
ret = FILE_IS_NOT_COMPRESSED;
done:
if (((ret == FILE_IS_COMPRESSED) || saveInvalid) && hdr) {
/*
* cache the uncompressed size away in the cnode
*/
if (!cnode_locked) {
/*
* we should never get here since the only place ret is set to FILE_IS_COMPRESSED
* is after the call to decmpfs_lock_compressed_data above
*/
decmpfs_lock_compressed_data(cp, 1);
cnode_locked = 1;
}
if (vnode_isdir(vp)) {
decmpfs_cnode_set_vnode_cached_size(cp, 64);
decmpfs_cnode_set_vnode_cached_nchildren(cp, decmpfs_get_directory_entries(hdr));
if (hdr->compression_type == DATALESS_PKG_CMPFS_TYPE) {
decmpfs_cnode_set_vnode_cached_total_size(cp, DECMPFS_PKG_SIZE(hdr->_size));
}
} else {
decmpfs_cnode_set_vnode_cached_size(cp, hdr->uncompressed_size);
}
decmpfs_cnode_set_vnode_state(cp, ret, 1);
decmpfs_cnode_set_vnode_cmp_type(cp, hdr->compression_type, 1);
/* remember if the xattr's size was equal to the minimal xattr */
if (hdr->attr_size == sizeof(decmpfs_disk_header)) {
decmpfs_cnode_set_vnode_minimal_xattr(cp, 1, 1);
}
if (ret == FILE_IS_COMPRESSED) {
/* update the ubc's size for this file */
ubc_setsize(vp, hdr->uncompressed_size);
/* update the decompression flags in the decmpfs cnode */
lck_rw_lock_shared(&decompressorsLock);
decmpfs_get_decompression_flags_func get_flags = decmp_get_func(vp, hdr->compression_type, get_flags);
if (get_flags) {
decompression_flags = get_flags(vp, decmpfs_ctx, hdr);
}
lck_rw_unlock_shared(&decompressorsLock);
decmpfs_cnode_set_decompression_flags(cp, decompression_flags);
}
} else {
/* we might have already taken the lock above; if so, skip taking it again by passing cnode_locked as the skiplock parameter */
decmpfs_cnode_set_vnode_state(cp, ret, cnode_locked);
}
if (cnode_locked) {
decmpfs_unlock_compressed_data(cp, 1);
}
if (hdr != NULL) {
kfree_data(hdr, alloc_size);
}
/*
* Trace the following parameters on return with event-id 0x03120014.
*
* @vp->v_id: vnode-id of the file being queried.
* @return: set to 1 is file is compressed.
*/
switch (ret) {
case FILE_IS_NOT_COMPRESSED:
DECMPFS_EMIT_TRACE_RETURN(DECMPDBG_FILE_IS_COMPRESSED, vp->v_id, 0);
return 0;
case FILE_IS_COMPRESSED:
case FILE_IS_CONVERTING:
DECMPFS_EMIT_TRACE_RETURN(DECMPDBG_FILE_IS_COMPRESSED, vp->v_id, 1);
return 1;
default:
/* unknown state, assume file is not compressed */
DECMPFS_EMIT_TRACE_RETURN(DECMPDBG_FILE_IS_COMPRESSED, vp->v_id, 0);
ErrorLogWithPath("unknown ret %d\n", ret);
return 0;
}
}
int
decmpfs_update_attributes(vnode_t vp, struct vnode_attr *vap)
{
int error = 0;
if (VATTR_IS_ACTIVE(vap, va_flags)) {
/* the BSD flags are being updated */
if (vap->va_flags & UF_COMPRESSED) {
/* the compressed bit is being set, did it change? */
struct vnode_attr va_fetch;
int old_flags = 0;
VATTR_INIT(&va_fetch);
VATTR_WANTED(&va_fetch, va_flags);
error = vnode_getattr(vp, &va_fetch, decmpfs_ctx);
if (error) {
return error;
}
old_flags = va_fetch.va_flags;
if (!(old_flags & UF_COMPRESSED)) {
/*
* Compression bit was turned on, make sure the file has the DECMPFS_XATTR_NAME attribute.
* This precludes anyone from using the UF_COMPRESSED bit for anything else, and it enforces
* an order of operation -- you must first do the setxattr and then the chflags.
*/
if (VATTR_IS_ACTIVE(vap, va_data_size)) {
/*
* don't allow the caller to set the BSD flag and the size in the same call
* since this doesn't really make sense
*/
vap->va_flags &= ~UF_COMPRESSED;
return 0;
}
decmpfs_header *hdr = NULL;
size_t alloc_size = 0;
error = decmpfs_fetch_compressed_header(vp, NULL, &hdr, 1, &alloc_size);
if (error == 0) {
/*
* Allow the flag to be set since the decmpfs attribute
* is present.
*
* If we're creating a dataless file we do not want to
* truncate it to zero which allows the file resolver to
* have more control over when truncation should happen.
* All other types of compressed files are truncated to
* zero.
*/
if (!decmpfs_type_is_dataless(hdr->compression_type)) {
VATTR_SET_ACTIVE(vap, va_data_size);
vap->va_data_size = 0;
}
} else if (error == ERANGE) {
/* the file had a decmpfs attribute but the type was out of range, so don't muck with the file's data size */
} else {
/* no DECMPFS_XATTR_NAME attribute, so deny the update */
vap->va_flags &= ~UF_COMPRESSED;
}
if (hdr != NULL) {
kfree_data(hdr, alloc_size);
}
}
}
}
return 0;
}
static int
wait_for_decompress(decmpfs_cnode *cp)
{
int state;
lck_mtx_lock(&decompress_channel_mtx);
do {
state = decmpfs_fast_get_state(cp);
if (state != FILE_IS_CONVERTING) {
/* file is not decompressing */
lck_mtx_unlock(&decompress_channel_mtx);
return state;
}
msleep((caddr_t)&decompress_channel, &decompress_channel_mtx, PINOD, "wait_for_decompress", NULL);
} while (1);
}
#pragma mark --- decmpfs hide query routines ---
int
decmpfs_hides_rsrc(vfs_context_t ctx, decmpfs_cnode *cp)
{
/*
* WARNING!!!
* callers may (and do) pass NULL for ctx, so we should only use it
* for this equality comparison
*
* This routine should only be called after a file has already been through decmpfs_file_is_compressed
*/
if (ctx == decmpfs_ctx) {
return 0;
}
if (!decmpfs_fast_file_is_compressed(cp)) {
return 0;
}
/* all compressed files hide their resource fork */
return 1;
}
int
decmpfs_hides_xattr(vfs_context_t ctx, decmpfs_cnode *cp, const char *xattr)
{
/*
* WARNING!!!
* callers may (and do) pass NULL for ctx, so we should only use it
* for this equality comparison
*
* This routine should only be called after a file has already been through decmpfs_file_is_compressed
*/
if (ctx == decmpfs_ctx) {
return 0;
}
if (strncmp(xattr, XATTR_RESOURCEFORK_NAME, sizeof(XATTR_RESOURCEFORK_NAME) - 1) == 0) {
return decmpfs_hides_rsrc(ctx, cp);
}
if (!decmpfs_fast_file_is_compressed(cp)) {
/* file is not compressed, so don't hide this xattr */
return 0;
}
if (strncmp(xattr, DECMPFS_XATTR_NAME, sizeof(DECMPFS_XATTR_NAME) - 1) == 0) {
/* it's our xattr, so hide it */
return 1;
}
/* don't hide this xattr */
return 0;
}
#pragma mark --- registration/validation routines ---
static inline int
registration_valid(const decmpfs_registration *registration)
{
return registration && ((registration->decmpfs_registration == DECMPFS_REGISTRATION_VERSION_V1) || (registration->decmpfs_registration == DECMPFS_REGISTRATION_VERSION_V3));
}
errno_t
register_decmpfs_decompressor(uint32_t compression_type, const decmpfs_registration *registration)
{
/* called by kexts to register decompressors */
errno_t ret = 0;
int locked = 0;
char resourceName[80];
if ((compression_type >= CMP_MAX) || !registration_valid(registration)) {
ret = EINVAL;
goto out;
}
lck_rw_lock_exclusive(&decompressorsLock); locked = 1;
/* make sure the registration for this type is zero */
if (decompressors[compression_type] != NULL) {
ret = EEXIST;
goto out;
}
decompressors[compression_type] = registration;
snprintf(resourceName, sizeof(resourceName), "com.apple.AppleFSCompression.Type%u", compression_type);
IOServicePublishResource(resourceName, TRUE);
out:
if (locked) {
lck_rw_unlock_exclusive(&decompressorsLock);
}
return ret;
}
errno_t
unregister_decmpfs_decompressor(uint32_t compression_type, decmpfs_registration *registration)
{
/* called by kexts to unregister decompressors */
errno_t ret = 0;
int locked = 0;
char resourceName[80];
if ((compression_type >= CMP_MAX) || !registration_valid(registration)) {
ret = EINVAL;
goto out;
}
lck_rw_lock_exclusive(&decompressorsLock); locked = 1;
if (decompressors[compression_type] != registration) {
ret = EEXIST;
goto out;
}
decompressors[compression_type] = NULL;
snprintf(resourceName, sizeof(resourceName), "com.apple.AppleFSCompression.Type%u", compression_type);
IOServicePublishResource(resourceName, FALSE);
out:
if (locked) {
lck_rw_unlock_exclusive(&decompressorsLock);
}
return ret;
}
static int
compression_type_valid(vnode_t vp, decmpfs_header *hdr)
{
/* fast pre-check to determine if the given compressor has checked in */
int ret = 0;
/* every compressor must have at least a fetch function */
lck_rw_lock_shared(&decompressorsLock);
if (decmp_get_func(vp, hdr->compression_type, fetch) != NULL) {
ret = 1;
}
lck_rw_unlock_shared(&decompressorsLock);
return ret;
}
#pragma mark --- compression/decompression routines ---
static int
decmpfs_fetch_uncompressed_data(vnode_t vp, decmpfs_cnode *cp, decmpfs_header *hdr, off_t offset, user_ssize_t size, int nvec, decmpfs_vector *vec, uint64_t *bytes_read)
{
/* get the uncompressed bytes for the specified region of vp by calling out to the registered compressor */
int err = 0;
*bytes_read = 0;
if (offset >= (off_t)hdr->uncompressed_size) {
/* reading past end of file; nothing to do */
err = 0;
goto out;
}
if (offset < 0) {
/* tried to read from before start of file */
err = EINVAL;
goto out;
}
if (hdr->uncompressed_size - offset < size) {
/* adjust size so we don't read past the end of the file */
size = (user_ssize_t)(hdr->uncompressed_size - offset);
}
if (size == 0) {
/* nothing to read */
err = 0;
goto out;
}
/*
* Trace the following parameters on entry with event-id 0x03120008.
*
* @vp->v_id: vnode-id of the file being decompressed.
* @hdr->compression_type: compression type.
* @offset: offset from where to fetch uncompressed data.
* @size: amount of uncompressed data to fetch.
*
* Please NOTE: @offset and @size can overflow in theory but
* here it is safe.
*/
DECMPFS_EMIT_TRACE_ENTRY(DECMPDBG_FETCH_UNCOMPRESSED_DATA, vp->v_id,
hdr->compression_type, (int)offset, (int)size);
lck_rw_lock_shared(&decompressorsLock);
decmpfs_fetch_uncompressed_data_func fetch = decmp_get_func(vp, hdr->compression_type, fetch);
if (fetch) {
err = fetch(vp, decmpfs_ctx, hdr, offset, size, nvec, vec, bytes_read);
lck_rw_unlock_shared(&decompressorsLock);
if (err == 0) {
uint64_t decompression_flags = decmpfs_cnode_get_decompression_flags(cp);
if (decompression_flags & DECMPFS_FLAGS_FORCE_FLUSH_ON_DECOMPRESS) {
#if !defined(__i386__) && !defined(__x86_64__)
int i;
for (i = 0; i < nvec; i++) {
assert(vec[i].size >= 0 && vec[i].size <= UINT_MAX);
flush_dcache64((addr64_t)(uintptr_t)vec[i].buf, (unsigned int)vec[i].size, FALSE);
}
#endif
}
} else {
decmpfs_ktriage_record(KTRIAGE_DECMPFS_FETCH_CALLBACK_FAILED, err);
}
} else {
decmpfs_ktriage_record(KTRIAGE_DECMPFS_COMPRESSOR_NOT_REGISTERED, hdr->compression_type);
err = ENOTSUP;
lck_rw_unlock_shared(&decompressorsLock);
}
/*
* Trace the following parameters on return with event-id 0x03120008.
*
* @vp->v_id: vnode-id of the file being decompressed.
* @bytes_read: amount of uncompressed bytes fetched in bytes.
* @err: value returned from this function.
*
* Please NOTE: @bytes_read can overflow in theory but here it is safe.
*/
DECMPFS_EMIT_TRACE_RETURN(DECMPDBG_FETCH_UNCOMPRESSED_DATA, vp->v_id,
(int)*bytes_read, err);
out:
return err;
}
static kern_return_t
commit_upl(upl_t upl, upl_offset_t pl_offset, size_t uplSize, int flags, int abort)
{
kern_return_t kr = 0;
#if CONFIG_IOSCHED
upl_unmark_decmp(upl);
#endif /* CONFIG_IOSCHED */
/* commit the upl pages */
if (abort) {
VerboseLog("aborting upl, flags 0x%08x\n", flags);
kr = ubc_upl_abort_range(upl, pl_offset, (upl_size_t)uplSize, flags);
if (kr != KERN_SUCCESS) {
ErrorLog("ubc_upl_abort_range error %d\n", (int)kr);
}
} else {
VerboseLog("committing upl, flags 0x%08x\n", flags | UPL_COMMIT_CLEAR_DIRTY);
kr = ubc_upl_commit_range(upl, pl_offset, (upl_size_t)uplSize, flags | UPL_COMMIT_CLEAR_DIRTY | UPL_COMMIT_WRITTEN_BY_KERNEL);
if (kr != KERN_SUCCESS) {
ErrorLog("ubc_upl_commit_range error %d\n", (int)kr);
}
}
return kr;
}
errno_t
decmpfs_pagein_compressed(struct vnop_pagein_args *ap, int *is_compressed, decmpfs_cnode *cp)
{
/* handles a page-in request from vfs for a compressed file */
int err = 0;
vnode_t vp = ap->a_vp;
upl_t pl = ap->a_pl;
upl_offset_t pl_offset = ap->a_pl_offset;
off_t f_offset = ap->a_f_offset;
size_t size = ap->a_size;
int flags = ap->a_flags;
off_t uplPos = 0;
user_ssize_t uplSize = 0;
user_ssize_t rounded_uplSize = 0;
size_t verify_block_size = 0;
void *data = NULL;
decmpfs_header *hdr = NULL;
size_t alloc_size = 0;
uint64_t cachedSize = 0;
uint32_t fs_bsize = 0;
int cmpdata_locked = 0;
int num_valid_pages = 0;
int num_invalid_pages = 0;
bool file_tail_page_valid = false;
if (!decmpfs_trylock_compressed_data(cp, 0)) {
return EAGAIN;
}
cmpdata_locked = 1;
if (flags & ~(UPL_IOSYNC | UPL_NOCOMMIT | UPL_NORDAHEAD)) {
DebugLogWithPath("pagein: unknown flags 0x%08x\n", (flags & ~(UPL_IOSYNC | UPL_NOCOMMIT | UPL_NORDAHEAD)));
}
err = decmpfs_fetch_compressed_header(vp, cp, &hdr, 0, &alloc_size);
if (err != 0) {
decmpfs_ktriage_record(KTRIAGE_DECMPFS_FETCH_HEADER_FAILED, err);
goto out;
}
cachedSize = hdr->uncompressed_size;
if (!compression_type_valid(vp, hdr)) {
/* compressor not registered */
decmpfs_ktriage_record(KTRIAGE_DECMPFS_COMPRESSOR_NOT_REGISTERED, hdr->compression_type);
err = ENOTSUP;
goto out;
}
/*
* can't page-in from a negative offset
* or if we're starting beyond the EOF
* or if the file offset isn't page aligned
* or the size requested isn't a multiple of PAGE_SIZE
*/
if (f_offset < 0 || f_offset >= cachedSize ||
(f_offset & PAGE_MASK_64) || (size & PAGE_MASK) || (pl_offset & PAGE_MASK)) {
decmpfs_ktriage_record(KTRIAGE_DECMPFS_IVALID_OFFSET, 0);
err = EINVAL;
goto out;
}
/*
* If the verify block size is larger than the page size, the UPL needs
* to be aligned to it, Since the UPL has been created by the filesystem,
* we will only check if the passed in UPL length conforms to the
* alignment requirements.
*/
err = VNOP_VERIFY(vp, f_offset, NULL, 0, &verify_block_size, NULL,
VNODE_VERIFY_DEFAULT, NULL);
if (err) {
ErrorLogWithPath("VNOP_VERIFY returned error = %d\n", err);
goto out;
} else if (verify_block_size) {
if (vp->v_mount->mnt_vfsstat.f_bsize > PAGE_SIZE) {
fs_bsize = vp->v_mount->mnt_vfsstat.f_bsize;
}
if (verify_block_size & (verify_block_size - 1)) {
ErrorLogWithPath("verify block size (%zu) is not power of 2, no verification will be done\n", verify_block_size);
err = EINVAL;
} else if (size % verify_block_size) {
ErrorLogWithPath("upl size (%zu) is not a multiple of verify block size (%zu)\n", (size_t)size, verify_block_size);
err = EINVAL;
} else if (fs_bsize) {
/*
* Filesystems requesting verification have to provide
* values for block sizes which are powers of 2.
*/
if (fs_bsize & (fs_bsize - 1)) {
ErrorLogWithPath("FS block size (%u) is greater than PAGE_SIZE (%d) and is not power of 2, no verification will be done\n",
fs_bsize, PAGE_SIZE);
err = EINVAL;
} else if (fs_bsize > verify_block_size) {
ErrorLogWithPath("FS block size (%u) is greater than verify block size (%zu), no verification will be done\n",
fs_bsize, verify_block_size);
err = EINVAL;
}
}
if (err) {
goto out;
}
}
#if CONFIG_IOSCHED
/* Mark the UPL as the requesting UPL for decompression */
upl_mark_decmp(pl);
#endif /* CONFIG_IOSCHED */
/* map the upl so we can fetch into it */
kern_return_t kr = ubc_upl_map(pl, (vm_offset_t*)&data);
if ((kr != KERN_SUCCESS) || (data == NULL)) {
decmpfs_ktriage_record(KTRIAGE_DECMPFS_UBC_UPL_MAP_FAILED, kr);
err = ENOSPC;
data = NULL;
#if CONFIG_IOSCHED
upl_unmark_decmp(pl);
#endif /* CONFIG_IOSCHED */
goto out;
}
uplPos = f_offset;
off_t max_size = cachedSize - f_offset;
if (size < max_size) {
rounded_uplSize = uplSize = size;
file_tail_page_valid = true;
} else {
uplSize = (user_ssize_t)max_size;
if (fs_bsize) {
/* First round up to fs_bsize */
rounded_uplSize = (uplSize + (fs_bsize - 1)) & ~(fs_bsize - 1);
/* then to PAGE_SIZE */
rounded_uplSize = MIN(size, round_page((vm_offset_t)rounded_uplSize));
} else {
rounded_uplSize = round_page((vm_offset_t)uplSize);
}
}
/* do the fetch */
decmpfs_vector vec;
decompress:
/* the mapped data pointer points to the first page of the page list, so we want to start filling in at an offset of pl_offset */
vec = (decmpfs_vector) {
.buf = (char*)data + pl_offset,
.size = size,
};
uint64_t did_read = 0;
if (decmpfs_fast_get_state(cp) == FILE_IS_CONVERTING) {
ErrorLogWithPath("unexpected pagein during decompress\n");
/*
* if the file is converting, this must be a recursive call to pagein from underneath a call to decmpfs_decompress_file;
* pretend that it succeeded but don't do anything since we're just going to write over the pages anyway
*/
err = 0;
} else {
if (verify_block_size <= PAGE_SIZE) {
err = decmpfs_fetch_uncompressed_data(vp, cp, hdr, uplPos, uplSize, 1, &vec, &did_read);
/* zero out whatever wasn't read */
if (did_read < rounded_uplSize) {
memset((char*)vec.buf + did_read, 0, (size_t)(rounded_uplSize - did_read));
}
} else {
off_t l_uplPos = uplPos;
off_t l_pl_offset = pl_offset;
user_ssize_t l_uplSize = uplSize;
upl_page_info_t *pl_info = ubc_upl_pageinfo(pl);
err = 0;
/*
* When the system page size is less than the "verify block size",
* the UPL passed may not consist solely of absent pages.
* We have to detect the "absent" pages and only decompress
* into those absent/invalid page ranges.
*
* Things that will change in each iteration of the loop :
*
* l_pl_offset = where we are inside the UPL [0, caller_upl_created_size)
* l_uplPos = the file offset the l_pl_offset corresponds to.
* l_uplSize = the size of the upl still unprocessed;
*
* In this picture, we have to do the transfer on 2 ranges
* (One 2 page range and one 3 page range) and the loop
* below will skip the first two pages and then identify
* the next two as invalid and fill those in and
* then skip the next one and then do the last pages.
*
* uplPos(file_offset)
* | uplSize
* 0 V<--------------> file_size
* |--------------------------------------------------->
* | | |V|V|I|I|V|I|I|I|
* ^
* | upl
* <------------------->
* |
* pl_offset
*
* uplSize will be clipped in case the UPL range exceeds
* the file size.
*
*/
while (l_uplSize) {
uint64_t l_did_read = 0;
int pl_offset_pg = (int)(l_pl_offset / PAGE_SIZE);
int pages_left_in_upl;
int start_pg;
int last_pg;
/*
* l_uplSize may start off less than the size of the upl,
* we have to round it up to PAGE_SIZE to calculate
* how many more pages are left.
*/
pages_left_in_upl = (int)(round_page((vm_offset_t)l_uplSize) / PAGE_SIZE);
/*
* scan from the beginning of the upl looking for the first
* non-valid page.... this will become the first page in
* the request we're going to make to
* 'decmpfs_fetch_uncompressed_data'... if all
* of the pages are valid, we won't call through
* to 'decmpfs_fetch_uncompressed_data'
*/
for (start_pg = 0; start_pg < pages_left_in_upl; start_pg++) {
if (!upl_valid_page(pl_info, pl_offset_pg + start_pg)) {
break;
}
}
num_valid_pages += start_pg;
/*
* scan from the starting invalid page looking for
* a valid page before the end of the upl is
* reached, if we find one, then it will be the
* last page of the request to 'decmpfs_fetch_uncompressed_data'
*/
for (last_pg = start_pg; last_pg < pages_left_in_upl; last_pg++) {
if (upl_valid_page(pl_info, pl_offset_pg + last_pg)) {
break;
}
}
if (start_pg < last_pg) {
off_t inval_offset = start_pg * PAGE_SIZE;
int inval_pages = last_pg - start_pg;
int inval_size = inval_pages * PAGE_SIZE;
decmpfs_vector l_vec;
num_invalid_pages += inval_pages;
if (inval_offset) {
did_read += inval_offset;
l_pl_offset += inval_offset;
l_uplPos += inval_offset;
l_uplSize -= inval_offset;
}
l_vec = (decmpfs_vector) {
.buf = (char*)data + l_pl_offset,
.size = inval_size,
};
err = decmpfs_fetch_uncompressed_data(vp, cp, hdr, l_uplPos,
MIN(l_uplSize, inval_size), 1, &l_vec, &l_did_read);
if (!err && (l_did_read != inval_size) && (l_uplSize > inval_size)) {
ErrorLogWithPath("Unexpected size fetch of decompressed data, l_uplSize = %d, l_did_read = %d, inval_size = %d\n",
(int)l_uplSize, (int)l_did_read, (int)inval_size);
err = EINVAL;
}
} else {
/* no invalid pages left */
l_did_read = l_uplSize;
if (!file_tail_page_valid) {
file_tail_page_valid = true;
}
}
if (err) {
break;
}
did_read += l_did_read;
l_pl_offset += l_did_read;
l_uplPos += l_did_read;
l_uplSize -= l_did_read;
}
/* Zero out the region after EOF in the last page (if needed) */
if (!err && !file_tail_page_valid && (uplSize < rounded_uplSize)) {
memset((char*)vec.buf + uplSize, 0, (size_t)(rounded_uplSize - uplSize));
}
}
}
if (err) {
decmpfs_ktriage_record(KTRIAGE_DECMPFS_FETCH_UNCOMPRESSED_DATA_FAILED, err)
DebugLogWithPath("decmpfs_fetch_uncompressed_data err %d\n", err);
int cmp_state = decmpfs_fast_get_state(cp);
if (cmp_state == FILE_IS_CONVERTING) {
DebugLogWithPath("cmp_state == FILE_IS_CONVERTING\n");
cmp_state = wait_for_decompress(cp);
if (cmp_state == FILE_IS_COMPRESSED) {
DebugLogWithPath("cmp_state == FILE_IS_COMPRESSED\n");
/* a decompress was attempted but it failed, let's try calling fetch again */
goto decompress;
}
}
if (cmp_state == FILE_IS_NOT_COMPRESSED) {
DebugLogWithPath("cmp_state == FILE_IS_NOT_COMPRESSED\n");
/* the file was decompressed after we started reading it */
*is_compressed = 0; /* instruct caller to fall back to its normal path */
}
}
if (!err && verify_block_size) {
size_t cur_verify_block_size = verify_block_size;
if ((err = VNOP_VERIFY(vp, uplPos, vec.buf, rounded_uplSize, &cur_verify_block_size, NULL, 0, NULL))) {
ErrorLogWithPath("Verification failed with error %d, uplPos = %lld, uplSize = %d, did_read = %d, valid_pages = %d, invalid_pages = %d, tail_page_valid = %d\n",
err, (long long)uplPos, (int)rounded_uplSize, (int)did_read, num_valid_pages, num_invalid_pages, file_tail_page_valid);
}
/* XXX : If the verify block size changes, redo the read */
}
#if CONFIG_IOSCHED
upl_unmark_decmp(pl);
#endif /* CONFIG_IOSCHED */
kr = ubc_upl_unmap(pl); data = NULL; /* make sure to set data to NULL so we don't try to unmap again below */
if (kr != KERN_SUCCESS) {
ErrorLogWithPath("ubc_upl_unmap error %d\n", (int)kr);
} else {
if (!err) {
/* commit our pages */
kr = commit_upl(pl, pl_offset, (size_t)rounded_uplSize, UPL_COMMIT_FREE_ON_EMPTY, 0 /* commit */);
/* If there were any pages after the page containing EOF, abort them. */
if (rounded_uplSize < size) {
kr = commit_upl(pl, (upl_offset_t)(pl_offset + rounded_uplSize), (size_t)(size - rounded_uplSize),
UPL_ABORT_FREE_ON_EMPTY | UPL_ABORT_ERROR, 1 /* abort */);
}
}
}
out:
if (data) {
ubc_upl_unmap(pl);
}
if (hdr != NULL) {
kfree_data(hdr, alloc_size);
}
if (cmpdata_locked) {
decmpfs_unlock_compressed_data(cp, 0);
}
if (err) {
#if 0
if (err != ENXIO && err != ENOSPC) {
char *path = zalloc(ZV_NAMEI);
panic("%s: decmpfs_pagein_compressed: err %d", vnpath(vp, path, PATH_MAX), err);
zfree(ZV_NAMEI, path);
}
#endif /* 0 */
ErrorLogWithPath("err %d\n", err);
}
return err;
}
errno_t
decmpfs_read_compressed(struct vnop_read_args *ap, int *is_compressed, decmpfs_cnode *cp)
{
/* handles a read request from vfs for a compressed file */
uio_t uio = ap->a_uio;
vnode_t vp = ap->a_vp;
int err = 0;
int countInt = 0;
off_t uplPos = 0;
user_ssize_t uplSize = 0;
user_ssize_t uplRemaining = 0;
off_t curUplPos = 0;
user_ssize_t curUplSize = 0;
kern_return_t kr = KERN_SUCCESS;
int abort_read = 0;
void *data = NULL;
uint64_t did_read = 0;
upl_t upl = NULL;
upl_page_info_t *pli = NULL;
decmpfs_header *hdr = NULL;
size_t alloc_size = 0;
uint64_t cachedSize = 0;
off_t uioPos = 0;
user_ssize_t uioRemaining = 0;
size_t verify_block_size = 0;
size_t alignment_size = PAGE_SIZE;
int cmpdata_locked = 0;
decmpfs_lock_compressed_data(cp, 0); cmpdata_locked = 1;
uplPos = uio_offset(uio);
uplSize = uio_resid(uio);
VerboseLogWithPath("uplPos %lld uplSize %lld\n", uplPos, uplSize);
cachedSize = decmpfs_cnode_get_vnode_cached_size(cp);
if ((uint64_t)uplPos + uplSize > cachedSize) {
/* truncate the read to the size of the file */
uplSize = (user_ssize_t)(cachedSize - uplPos);
}
/* give the cluster layer a chance to fill in whatever it already has */
countInt = (uplSize > INT_MAX) ? INT_MAX : (int)uplSize;
err = cluster_copy_ubc_data(vp, uio, &countInt, 0);
if (err != 0) {
goto out;
}
/* figure out what's left */
uioPos = uio_offset(uio);
uioRemaining = uio_resid(uio);
if ((uint64_t)uioPos + uioRemaining > cachedSize) {
/* truncate the read to the size of the file */
uioRemaining = (user_ssize_t)(cachedSize - uioPos);
}
if (uioRemaining <= 0) {
/* nothing left */
goto out;
}
err = decmpfs_fetch_compressed_header(vp, cp, &hdr, 0, &alloc_size);
if (err != 0) {
goto out;
}
if (!compression_type_valid(vp, hdr)) {
err = ENOTSUP;
goto out;
}
uplPos = uioPos;
uplSize = uioRemaining;
#if COMPRESSION_DEBUG
DebugLogWithPath("uplPos %lld uplSize %lld\n", (uint64_t)uplPos, (uint64_t)uplSize);
#endif
lck_rw_lock_shared(&decompressorsLock);
decmpfs_adjust_fetch_region_func adjust_fetch = decmp_get_func(vp, hdr->compression_type, adjust_fetch);
if (adjust_fetch) {
/* give the compressor a chance to adjust the portion of the file that we read */
adjust_fetch(vp, decmpfs_ctx, hdr, &uplPos, &uplSize);
VerboseLogWithPath("adjusted uplPos %lld uplSize %lld\n", (uint64_t)uplPos, (uint64_t)uplSize);
}
lck_rw_unlock_shared(&decompressorsLock);
/* clip the adjusted size to the size of the file */
if ((uint64_t)uplPos + uplSize > cachedSize) {
/* truncate the read to the size of the file */
uplSize = (user_ssize_t)(cachedSize - uplPos);
}
if (uplSize <= 0) {
/* nothing left */
goto out;
}
/*
* since we're going to create a upl for the given region of the file,
* make sure we're on page boundaries
*/
/* If the verify block size is larger than the page size, the UPL needs to aligned to it */
err = VNOP_VERIFY(vp, uplPos, NULL, 0, &verify_block_size, NULL, VNODE_VERIFY_DEFAULT, NULL);
if (err) {
goto out;
} else if (verify_block_size) {
if (verify_block_size & (verify_block_size - 1)) {
ErrorLogWithPath("verify block size is not power of 2, no verification will be done\n");
verify_block_size = 0;
} else if (verify_block_size > PAGE_SIZE) {
alignment_size = verify_block_size;
}
}
if (uplPos & (alignment_size - 1)) {
/* round position down to page boundary */
uplSize += (uplPos & (alignment_size - 1));
uplPos &= ~(alignment_size - 1);
}
/* round size up to alignement_size multiple */
uplSize = (uplSize + (alignment_size - 1)) & ~(alignment_size - 1);
VerboseLogWithPath("new uplPos %lld uplSize %lld\n", (uint64_t)uplPos, (uint64_t)uplSize);
uplRemaining = uplSize;
curUplPos = uplPos;
curUplSize = 0;
while (uplRemaining > 0) {
/* start after the last upl */
curUplPos += curUplSize;
/* clip to max upl size */
curUplSize = uplRemaining;
if (curUplSize > MAX_UPL_SIZE_BYTES) {
curUplSize = MAX_UPL_SIZE_BYTES;
}
/* create the upl */
kr = ubc_create_upl_kernel(vp, curUplPos, (int)curUplSize, &upl, &pli, UPL_SET_LITE, VM_KERN_MEMORY_FILE);
if (kr != KERN_SUCCESS) {
ErrorLogWithPath("ubc_create_upl error %d\n", (int)kr);
err = EINVAL;
goto out;
}
VerboseLogWithPath("curUplPos %lld curUplSize %lld\n", (uint64_t)curUplPos, (uint64_t)curUplSize);
#if CONFIG_IOSCHED
/* Mark the UPL as the requesting UPL for decompression */
upl_mark_decmp(upl);
#endif /* CONFIG_IOSCHED */
/* map the upl */
kr = ubc_upl_map(upl, (vm_offset_t*)&data);
if (kr != KERN_SUCCESS) {
commit_upl(upl, 0, curUplSize, UPL_ABORT_FREE_ON_EMPTY, 1);
#if 0
char *path = zalloc(ZV_NAMEI);
panic("%s: decmpfs_read_compressed: ubc_upl_map error %d", vnpath(vp, path, PATH_MAX), (int)kr);
zfree(ZV_NAMEI, path);
#else /* 0 */
ErrorLogWithPath("ubc_upl_map kr=0x%x\n", (int)kr);
#endif /* 0 */
err = EINVAL;
goto out;
}
/* make sure the map succeeded */
if (!data) {
commit_upl(upl, 0, curUplSize, UPL_ABORT_FREE_ON_EMPTY, 1);
ErrorLogWithPath("ubc_upl_map mapped null\n");
err = EINVAL;
goto out;
}
/* fetch uncompressed data into the mapped upl */
decmpfs_vector vec;
decompress:
vec = (decmpfs_vector){ .buf = data, .size = curUplSize };
err = decmpfs_fetch_uncompressed_data(vp, cp, hdr, curUplPos, curUplSize, 1, &vec, &did_read);
if (err) {
ErrorLogWithPath("decmpfs_fetch_uncompressed_data err %d\n", err);
/* maybe the file is converting to decompressed */
int cmp_state = decmpfs_fast_get_state(cp);
if (cmp_state == FILE_IS_CONVERTING) {
ErrorLogWithPath("cmp_state == FILE_IS_CONVERTING\n");
cmp_state = wait_for_decompress(cp);
if (cmp_state == FILE_IS_COMPRESSED) {
ErrorLogWithPath("cmp_state == FILE_IS_COMPRESSED\n");
/* a decompress was attempted but it failed, let's try fetching again */
goto decompress;
}
}
if (cmp_state == FILE_IS_NOT_COMPRESSED) {
ErrorLogWithPath("cmp_state == FILE_IS_NOT_COMPRESSED\n");
/* the file was decompressed after we started reading it */
abort_read = 1; /* we're not going to commit our data */
*is_compressed = 0; /* instruct caller to fall back to its normal path */
}
kr = KERN_FAILURE;
did_read = 0;
}
/* zero out the remainder of the last page */
memset((char*)data + did_read, 0, (size_t)(curUplSize - did_read));
if (!err && verify_block_size) {
size_t cur_verify_block_size = verify_block_size;
if ((err = VNOP_VERIFY(vp, curUplPos, data, curUplSize, &cur_verify_block_size, NULL, 0, NULL))) {
ErrorLogWithPath("Verification failed with error %d\n", err);
abort_read = 1;
}
/* XXX : If the verify block size changes, redo the read */
}
kr = ubc_upl_unmap(upl);
if (kr == KERN_SUCCESS) {
if (abort_read) {
kr = commit_upl(upl, 0, curUplSize, UPL_ABORT_FREE_ON_EMPTY, 1);
} else {
VerboseLogWithPath("uioPos %lld uioRemaining %lld\n", (uint64_t)uioPos, (uint64_t)uioRemaining);
if (uioRemaining) {
off_t uplOff = uioPos - curUplPos;
if (uplOff < 0) {
ErrorLogWithPath("uplOff %lld should never be negative\n", (int64_t)uplOff);
err = EINVAL;
} else if (uplOff > INT_MAX) {
ErrorLogWithPath("uplOff %lld too large\n", (int64_t)uplOff);
err = EINVAL;
} else {
off_t count = curUplPos + curUplSize - uioPos;
if (count < 0) {
/* this upl is entirely before the uio */
} else {
if (count > uioRemaining) {
count = uioRemaining;
}
int icount = (count > INT_MAX) ? INT_MAX : (int)count;
int io_resid = icount;
err = cluster_copy_upl_data(uio, upl, (int)uplOff, &io_resid);
int copied = icount - io_resid;
VerboseLogWithPath("uplOff %lld count %lld copied %lld\n", (uint64_t)uplOff, (uint64_t)count, (uint64_t)copied);
if (err) {
ErrorLogWithPath("cluster_copy_upl_data err %d\n", err);
}
uioPos += copied;
uioRemaining -= copied;
}
}
}
kr = commit_upl(upl, 0, curUplSize, UPL_COMMIT_FREE_ON_EMPTY | UPL_COMMIT_INACTIVATE, 0);
if (err) {
goto out;
}
}
} else {
ErrorLogWithPath("ubc_upl_unmap error %d\n", (int)kr);
}
uplRemaining -= curUplSize;
}
out:
if (hdr != NULL) {
kfree_data(hdr, alloc_size);
}
if (cmpdata_locked) {
decmpfs_unlock_compressed_data(cp, 0);
}
if (err) {/* something went wrong */
ErrorLogWithPath("err %d\n", err);
return err;
}
#if COMPRESSION_DEBUG
uplSize = uio_resid(uio);
if (uplSize) {
VerboseLogWithPath("still %lld bytes to copy\n", uplSize);
}
#endif
return 0;
}
int
decmpfs_free_compressed_data(vnode_t vp, decmpfs_cnode *cp)
{
/*
* call out to the decompressor to free remove any data associated with this compressed file
* then delete the file's compression xattr
*/
decmpfs_header *hdr = NULL;
size_t alloc_size = 0;
/*
* Trace the following parameters on entry with event-id 0x03120010.
*
* @vp->v_id: vnode-id of the file for which to free compressed data.
*/
DECMPFS_EMIT_TRACE_ENTRY(DECMPDBG_FREE_COMPRESSED_DATA, vp->v_id);
int err = decmpfs_fetch_compressed_header(vp, cp, &hdr, 0, &alloc_size);
if (err) {
ErrorLogWithPath("decmpfs_fetch_compressed_header err %d\n", err);
} else {
lck_rw_lock_shared(&decompressorsLock);
decmpfs_free_compressed_data_func free_data = decmp_get_func(vp, hdr->compression_type, free_data);
if (free_data) {
err = free_data(vp, decmpfs_ctx, hdr);
} else {
/* nothing to do, so no error */
err = 0;
}
lck_rw_unlock_shared(&decompressorsLock);
if (err != 0) {
ErrorLogWithPath("decompressor err %d\n", err);
}
}
/*
* Trace the following parameters on return with event-id 0x03120010.
*
* @vp->v_id: vnode-id of the file for which to free compressed data.
* @err: value returned from this function.
*/
DECMPFS_EMIT_TRACE_RETURN(DECMPDBG_FREE_COMPRESSED_DATA, vp->v_id, err);
/* delete the xattr */
err = vn_removexattr(vp, DECMPFS_XATTR_NAME, 0, decmpfs_ctx);
if (hdr != NULL) {
kfree_data(hdr, alloc_size);
}
return err;
}
#pragma mark --- file conversion routines ---
static int
unset_compressed_flag(vnode_t vp)
{
int err = 0;
struct vnode_attr va;
struct fsioc_cas_bsdflags cas;
int i;
# define MAX_CAS_BSDFLAGS_LOOPS 4
/* UF_COMPRESSED should be manipulated only with FSIOC_CAS_BSDFLAGS */
for (i = 0; i < MAX_CAS_BSDFLAGS_LOOPS; i++) {
VATTR_INIT(&va);
VATTR_WANTED(&va, va_flags);
err = vnode_getattr(vp, &va, decmpfs_ctx);
if (err != 0) {
ErrorLogWithPath("vnode_getattr err %d, num retries %d\n", err, i);
goto out;
}
cas.expected_flags = va.va_flags;
cas.new_flags = va.va_flags & ~UF_COMPRESSED;
err = VNOP_IOCTL(vp, FSIOC_CAS_BSDFLAGS, (caddr_t)&cas, FWRITE, decmpfs_ctx);
if ((err == 0) && (va.va_flags == cas.actual_flags)) {
goto out;
}
if ((err != 0) && (err != EAGAIN)) {
break;
}
}
/* fallback to regular chflags if FSIOC_CAS_BSDFLAGS is not supported */
if (err == ENOTTY) {
VATTR_INIT(&va);
VATTR_SET(&va, va_flags, cas.new_flags);
err = vnode_setattr(vp, &va, decmpfs_ctx);
if (err != 0) {
ErrorLogWithPath("vnode_setattr err %d\n", err);
}
} else if (va.va_flags != cas.actual_flags) {
ErrorLogWithPath("FSIOC_CAS_BSDFLAGS err: flags mismatc. actual (%x) expected (%x), num retries %d\n", cas.actual_flags, va.va_flags, i);
} else if (err != 0) {
ErrorLogWithPath("FSIOC_CAS_BSDFLAGS err %d, num retries %d\n", err, i);
}
out:
return err;
}
int
decmpfs_decompress_file(vnode_t vp, decmpfs_cnode *cp, off_t toSize, int truncate_okay, int skiplock)
{
/* convert a compressed file to an uncompressed file */
int err = 0;
char *data = NULL;
uio_t uio_w = 0;
off_t offset = 0;
uint32_t old_state = 0;
uint32_t new_state = 0;
int update_file_state = 0;
size_t allocSize = 0;
decmpfs_header *hdr = NULL;
size_t hdr_size = 0;
int cmpdata_locked = 0;
off_t remaining = 0;
uint64_t uncompressed_size = 0;
/*
* Trace the following parameters on entry with event-id 0x03120000.
*
* @vp->v_id: vnode-id of the file being decompressed.
* @toSize: uncompress given bytes of the file.
* @truncate_okay: on error it is OK to truncate.
* @skiplock: compressed data is locked, skip locking again.
*
* Please NOTE: @toSize can overflow in theory but here it is safe.
*/
DECMPFS_EMIT_TRACE_ENTRY(DECMPDBG_DECOMPRESS_FILE, vp->v_id,
(int)toSize, truncate_okay, skiplock);
if (!skiplock) {
decmpfs_lock_compressed_data(cp, 1); cmpdata_locked = 1;
}
decompress:
old_state = decmpfs_fast_get_state(cp);
switch (old_state) {
case FILE_IS_NOT_COMPRESSED:
{
/* someone else decompressed the file */
err = 0;
goto out;
}
case FILE_TYPE_UNKNOWN:
{
/* the file is in an unknown state, so update the state and retry */
(void)decmpfs_file_is_compressed(vp, cp);
/* try again */
goto decompress;
}
case FILE_IS_COMPRESSED:
{
/* the file is compressed, so decompress it */
break;
}
default:
{
/*
* this shouldn't happen since multiple calls to decmpfs_decompress_file lock each other out,
* and when decmpfs_decompress_file returns, the state should be always be set back to
* FILE_IS_NOT_COMPRESSED or FILE_IS_UNKNOWN
*/
err = EINVAL;
goto out;
}
}
err = decmpfs_fetch_compressed_header(vp, cp, &hdr, 0, &hdr_size);
if (err != 0) {
goto out;
}
uncompressed_size = hdr->uncompressed_size;
if (toSize == -1) {
toSize = hdr->uncompressed_size;
}
if (toSize == 0) {
/* special case truncating the file to zero bytes */
goto nodecmp;
} else if ((uint64_t)toSize > hdr->uncompressed_size) {
/* the caller is trying to grow the file, so we should decompress all the data */
toSize = hdr->uncompressed_size;
}
allocSize = MIN(64 * 1024, (size_t)toSize);
data = (char *)kalloc_data(allocSize, Z_WAITOK);
if (!data) {
err = ENOMEM;
goto out;
}
uio_w = uio_create(1, 0LL, UIO_SYSSPACE, UIO_WRITE);
if (!uio_w) {
err = ENOMEM;
goto out;
}
uio_w->uio_flags |= UIO_FLAGS_IS_COMPRESSED_FILE;
remaining = toSize;
/* tell the buffer cache that this is an empty file */
ubc_setsize(vp, 0);
/* if we got here, we need to decompress the file */
decmpfs_cnode_set_vnode_state(cp, FILE_IS_CONVERTING, 1);
while (remaining > 0) {
/* loop decompressing data from the file and writing it into the data fork */
uint64_t bytes_read = 0;
decmpfs_vector vec = { .buf = data, .size = (user_ssize_t)MIN(allocSize, remaining) };
err = decmpfs_fetch_uncompressed_data(vp, cp, hdr, offset, vec.size, 1, &vec, &bytes_read);
if (err != 0) {
ErrorLogWithPath("decmpfs_fetch_uncompressed_data err %d\n", err);
goto out;
}
if (bytes_read == 0) {
/* we're done reading data */
break;
}
uio_reset(uio_w, offset, UIO_SYSSPACE, UIO_WRITE);
err = uio_addiov(uio_w, CAST_USER_ADDR_T(data), (user_size_t)bytes_read);
if (err != 0) {
ErrorLogWithPath("uio_addiov err %d\n", err);
err = ENOMEM;
goto out;
}
err = VNOP_WRITE(vp, uio_w, 0, decmpfs_ctx);
if (err != 0) {
/* if the write failed, truncate the file to zero bytes */
ErrorLogWithPath("VNOP_WRITE err %d\n", err);
break;
}
offset += bytes_read;
remaining -= bytes_read;
}
if (err == 0) {
if (offset != toSize) {
ErrorLogWithPath("file decompressed to %lld instead of %lld\n", offset, toSize);
err = EINVAL;
goto out;
}
}
if (err == 0) {
/* sync the data and metadata */
err = VNOP_FSYNC(vp, MNT_WAIT, decmpfs_ctx);
if (err != 0) {
ErrorLogWithPath("VNOP_FSYNC err %d\n", err);
goto out;
}
}
if (err != 0) {
/* write, setattr, or fsync failed */
ErrorLogWithPath("aborting decompress, err %d\n", err);
if (truncate_okay) {
/* truncate anything we might have written */
int error = vnode_setsize(vp, 0, 0, decmpfs_ctx);
ErrorLogWithPath("vnode_setsize err %d\n", error);
}
goto out;
}
nodecmp:
/* if we're truncating the file to zero bytes, we'll skip ahead to here */
/* unset the compressed flag */
unset_compressed_flag(vp);
/* free the compressed data associated with this file */
err = decmpfs_free_compressed_data(vp, cp);
if (err != 0) {
ErrorLogWithPath("decmpfs_free_compressed_data err %d\n", err);
}
/*
* even if free_compressed_data or vnode_getattr/vnode_setattr failed, return success
* since we succeeded in writing all of the file data to the data fork
*/
err = 0;
/* if we got this far, the file was successfully decompressed */
update_file_state = 1;
new_state = FILE_IS_NOT_COMPRESSED;
#if COMPRESSION_DEBUG
{
uint64_t filesize = 0;
vnsize(vp, &filesize);
DebugLogWithPath("new file size %lld\n", filesize);
}
#endif
out:
if (hdr != NULL) {
kfree_data(hdr, hdr_size);
}
kfree_data(data, allocSize);
if (uio_w) {
uio_free(uio_w);
}
if (err != 0) {
/* if there was a failure, reset compression flags to unknown and clear the buffer cache data */
update_file_state = 1;
new_state = FILE_TYPE_UNKNOWN;
if (uncompressed_size) {
ubc_setsize(vp, 0);
ubc_setsize(vp, uncompressed_size);
}
}
if (update_file_state) {
lck_mtx_lock(&decompress_channel_mtx);
decmpfs_cnode_set_vnode_state(cp, new_state, 1);
wakeup((caddr_t)&decompress_channel); /* wake up anyone who might have been waiting for decompression */
lck_mtx_unlock(&decompress_channel_mtx);
}
if (cmpdata_locked) {
decmpfs_unlock_compressed_data(cp, 1);
}
/*
* Trace the following parameters on return with event-id 0x03120000.
*
* @vp->v_id: vnode-id of the file being decompressed.
* @err: value returned from this function.
*/
DECMPFS_EMIT_TRACE_RETURN(DECMPDBG_DECOMPRESS_FILE, vp->v_id, err);
return err;
}
#pragma mark --- Type1 compressor ---
/*
* The "Type1" compressor stores the data fork directly in the compression xattr
*/
static int
decmpfs_validate_compressed_file_Type1(__unused vnode_t vp, __unused vfs_context_t ctx, decmpfs_header *hdr)
{
int err = 0;
if (hdr->uncompressed_size + sizeof(decmpfs_disk_header) != (uint64_t)hdr->attr_size) {
err = EINVAL;
goto out;
}
out:
return err;
}
static int
decmpfs_fetch_uncompressed_data_Type1(__unused vnode_t vp, __unused vfs_context_t ctx, decmpfs_header *hdr, off_t offset, user_ssize_t size, int nvec, decmpfs_vector *vec, uint64_t *bytes_read)
{
int err = 0;
int i;
user_ssize_t remaining;
if (hdr->uncompressed_size + sizeof(decmpfs_disk_header) != (uint64_t)hdr->attr_size) {
err = EINVAL;
goto out;
}
#if COMPRESSION_DEBUG
static int dummy = 0; // prevent syslog from coalescing printfs
DebugLogWithPath("%d memcpy %lld at %lld\n", dummy++, size, (uint64_t)offset);
#endif
remaining = size;
for (i = 0; (i < nvec) && (remaining > 0); i++) {
user_ssize_t curCopy = vec[i].size;
if (curCopy > remaining) {
curCopy = remaining;
}
memcpy(vec[i].buf, hdr->attr_bytes + offset, curCopy);
offset += curCopy;
remaining -= curCopy;
}
if ((bytes_read) && (err == 0)) {
*bytes_read = (size - remaining);
}
out:
return err;
}
SECURITY_READ_ONLY_EARLY(static decmpfs_registration) Type1Reg =
{
.decmpfs_registration = DECMPFS_REGISTRATION_VERSION,
.validate = decmpfs_validate_compressed_file_Type1,
.adjust_fetch = NULL,/* no adjust necessary */
.fetch = decmpfs_fetch_uncompressed_data_Type1,
.free_data = NULL,/* no free necessary */
.get_flags = NULL/* no flags */
};
#pragma mark --- decmpfs initialization ---
void
decmpfs_init(void)
{
static int done = 0;
if (done) {
return;
}
decmpfs_ctx = vfs_context_create(vfs_context_kernel());
register_decmpfs_decompressor(CMP_Type1, &Type1Reg);
ktriage_register_subsystem_strings(KDBG_TRIAGE_SUBSYS_DECMPFS, &ktriage_decmpfs_subsystem_strings);
done = 1;
}
#endif /* FS_COMPRESSION */
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