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internal.h
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/**
* @file
*
* @brief Internal definitions and macros for mmapstorage and its unit tests
*
* @copyright BSD License (see LICENSE.md or https://www.libelektra.org)
*
*/
#ifndef ELEKTRA_PLUGIN_MMAPSTORAGE_INTERNAL_H
#define ELEKTRA_PLUGIN_MMAPSTORAGE_INTERNAL_H
#define SIZEOF_KEY (sizeof (Key))
#define SIZEOF_KEY_PTR (sizeof (Key *))
#define SIZEOF_KEYSET (sizeof (KeySet))
#define SIZEOF_MMAPHEADER (sizeof (MmapHeader))
#define SIZEOF_MMAPMETADATA (sizeof (MmapMetaData))
#define SIZEOF_MMAPFOOTER (sizeof (MmapFooter))
#define OFFSET_MAGIC_KEYSET (SIZEOF_MMAPHEADER)
#ifdef ELEKTRA_ENABLE_OPTIMIZATIONS
/** Squeeze OPMPHM structs between other magic data, to automatically trigger verification fail on non-OPMPHM builds. */
#define OFFSET_MAGIC_OPMPHM (OFFSET_MAGIC_KEYSET + SIZEOF_KEYSET)
#define OFFSET_MAGIC_OPMPHMPREDICTOR (OFFSET_MAGIC_OPMPHM + sizeof (Opmphm))
#define OFFSET_MAGIC_KEY (OFFSET_MAGIC_OPMPHMPREDICTOR + sizeof (OpmphmPredictor))
#else
#define OFFSET_MAGIC_KEY (OFFSET_MAGIC_KEYSET + SIZEOF_KEYSET)
#endif
#define OFFSET_MAGIC_MMAPMETADATA (OFFSET_MAGIC_KEY + SIZEOF_KEY)
#ifdef ELEKTRA_ENABLE_OPTIMIZATIONS
#define OFFSET_OPMPHM (OFFSET_MAGIC_MMAPMETADATA + SIZEOF_MMAPMETADATA)
#define OFFSET_OPMPHMPREDICTOR (OFFSET_OPMPHM + sizeof (Opmphm))
#define OFFSET_MMAPMETADATA (OFFSET_OPMPHMPREDICTOR + sizeof (OpmphmPredictor))
#else
#define OFFSET_MMAPMETADATA (OFFSET_MAGIC_MMAPMETADATA + SIZEOF_MMAPMETADATA)
#endif
#define OFFSET_GLOBAL_KEYSET (OFFSET_MMAPMETADATA + SIZEOF_MMAPMETADATA)
#define OFFSET_KEYSET (OFFSET_GLOBAL_KEYSET + SIZEOF_KEYSET)
/** Minimum size (lower bound) of mapped region (header, metadata, footer) */
#ifdef ELEKTRA_ENABLE_OPTIMIZATIONS
#define ELEKTRA_MMAP_MINSIZE \
(SIZEOF_MMAPHEADER + (SIZEOF_MMAPMETADATA * 2) + (SIZEOF_KEYSET * 2) + (sizeof (Opmphm) * 2) + (sizeof (OpmphmPredictor) * 2) + \
SIZEOF_KEY + SIZEOF_MMAPFOOTER)
#else
#define ELEKTRA_MMAP_MINSIZE (SIZEOF_MMAPHEADER + (SIZEOF_MMAPMETADATA * 2) + (SIZEOF_KEYSET * 2) + SIZEOF_KEY + SIZEOF_MMAPFOOTER)
#endif
/** Magic byte order marker, as used by UTF. */
#define ELEKTRA_MMAP_MAGIC_BOM (0xFEFF)
/** Magic number used in mmap format (8 bytes). Previously used: 0x0A6172746B656C45 */
#define ELEKTRA_MAGIC_MMAP_NUMBER (0x0A3472746B656C45)
/** Mmap format version (1 byte). Increment on breaking changes to invalidate old files. */
#define ELEKTRA_MMAP_FORMAT_VERSION (3)
/** Mmap temp file template */
#define ELEKTRA_MMAP_TMP_NAME "/tmp/elektraMmapTmpXXXXXX"
/** Buffer size for file I/O */
#define ELEKTRA_MMAP_BUFSIZE (4096)
#define STDOUT_FILENAME ("/dev/stdout")
#define STDIN_FILENAME ("/dev/stdin")
/** Suppress warnings in cache mode to debug level */
#define ELEKTRA_MMAP_LOG_WARNING(...) \
if (test_bit (mode, MODE_GLOBALCACHE)) \
{ \
ELEKTRA_LOG_DEBUG (__VA_ARGS__); \
} \
else \
{ \
ELEKTRA_LOG_WARNING (__VA_ARGS__); \
}
/** Flags for mmap file format. We intentionally do not use enums,
such that the flags can be fit into uint8_t. */
/** Defines whether file was written with checksum on or off. */
#define MMAP_FLAG_CHECKSUM (1)
/** Defines whether file was written with config timestamps (global cache mode). */
#define MMAP_FLAG_TIMESTAMPS (1 << 1)
/** Defines whether file was written with opmphm data structures. */
#define MMAP_FLAG_OPMPHM (1 << 2)
/**
* Internal MmapAddr structure.
* Used for functions passing around relevant pointers into the mmap region.
* The write functions increment the pointers by the number of bytes written,
* such that the next iteration or function writes to the correct (free) place.
*/
struct _mmapAddr
{
// clang-format off
KeySet * const globalKsPtr; /**<Pointer to the global KeySet struct. */
KeySet * const ksPtr; /**<Pointer to the (main) KeySet struct. */
char * metaKsPtr; /**<Pointer to the current meta KeySet structs. */
char * globalKsArrayPtr; /**<Pointer to the current global KeySet->array. */
char * ksArrayPtr; /**<Pointer to the current KeySet->array. */
char * metaKsArrayPtr; /**<Pointer to the current meta KeySet->array. */
char * keyPtr; /**<Pointer to the current Key struct. */
char * dataPtr; /**<Pointer to the data region, where Key->key and Key->data is stored. */
const uintptr_t mmapAddrInt; /**<Address of the mapped region as integer. */
// clang-format on
};
typedef struct _mmapAddr MmapAddr;
/* Header, metadata and footer needed for mmap file format */
typedef struct _mmapHeader MmapHeader;
typedef struct _mmapMetaData MmapMetaData;
typedef struct _mmapFooter MmapFooter;
/**
* Mmap information header
*
* Changes to this struct can/will break compatibility with existing files.
* If a breaking changed needs to be introduced, change `ELEKTRA_MAGIC_MMAP_NUMBER`
* to a previously unused value and increment `ELEKTRA_MMAP_FORMAT_VERSION`
* to avoid undefined behaviour.
*
* Shall contain only fixed-width types.
*/
struct _mmapHeader
{
// clang-format off
uint64_t mmapMagicNumber; /**<Magic number for consistency check */
uint64_t allocSize; /**<Size of the complete allocation in bytes */
uint64_t cksumSize; /**<Size of the critical data for checksum (structs, pointers, sizes)*/
uint32_t checksum; /**<Checksum of the data */
uint8_t formatFlags; /**<Mmap format flags (e.g. checksum ON/OFF) */
uint8_t formatVersion; /**<Mmap format version */
// two bytes which are otherwise padding or packed away are reserved for future use
uint8_t reservedA; /**<Reserved byte for future use */
uint8_t reservedB; /**<Reserved byte for future use */
// clang-format on
};
#define STATIC_SIZEOF_MMAPHEADER 32
#define STATIC_HEADER_OFFSETOF_MAGICNUMBER 0
#define STATIC_HEADER_OFFSETOF_ALLOCSIZE 8
#define STATIC_HEADER_OFFSETOF_CHECKSUMSIZE 16
#define STATIC_HEADER_OFFSETOF_CHECKSUM 24
#define STATIC_HEADER_OFFSETOF_FORMATFLAGS 28
#define STATIC_HEADER_OFFSETOF_FORMATVERSION 29
#define STATIC_HEADER_OFFSETOF_RESERVED_A 30
#define STATIC_HEADER_OFFSETOF_RESERVED_B 31
/**
* Mmap meta-data
*/
struct _mmapMetaData
{
// clang-format off
size_t numKeySets; /**<Number of KeySets inlcuding meta KS */
size_t ksAlloc; /**<Sum of all KeySet->alloc sizes */
size_t numKeys; /**<Number of Keys including meta Keys */
// clang-format on
};
/**
* Mmap information footer
*
* shall contain only fixed-width types
*/
struct _mmapFooter
{
// clang-format off
uint64_t mmapMagicNumber; /**<Magic number for consistency check */
// clang-format on
};
#define STATIC_SIZEOF_MMAPFOOTER 8
#define STATIC_FOOTER_OFFSETOF_MAGICNUMBER 0
#endif