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/*
SSSD
Mmap Cache Common header
Copyright (C) Simo Sorce <ssorce@redhat.com> 2011
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _MMAP_CACHE_H_
#define _MMAP_CACHE_H_
#include "util/murmurhash3.h"
/* NOTE: all the code here assumes that writing a uint32_t nto mmapped
* memory is an atomic operation and can't be split in multiple
* non-atomic operations */
typedef uint32_t rel_ptr_t;
/* align macros */
#define MC_8 sizeof(uint8_t)
#define MC_32 sizeof(uint32_t)
#define MC_64 sizeof(uint64_t)
#define MC_ALIGN32(size) ( ((size) + MC_32 -1) & (~(MC_32 -1)) )
#define MC_ALIGN64(size) ( ((size) + MC_64 -1) & (~(MC_64 -1)) )
#define MC_HEADER_SIZE MC_ALIGN64(sizeof(struct sss_mc_header))
#define MC_HT_SIZE(elems) ( (elems) * MC_32 )
#define MC_HT_ELEMS(size) ( (size) / MC_32 )
#define MC_DT_SIZE(elems, payload) ( (elems) * (payload) )
#define MC_FT_SIZE(elems) ( (elems) / 8 )
/* ^^ 8 bits per byte so we need just elems/8 bytes to represent all blocks */
#define MC_PTR_ADD(ptr, bytes) (void *)((uint8_t *)(ptr) + (bytes))
#define MC_PTR_DIFF(ptr, base) ((uint8_t *)(ptr) - (uint8_t *)(base))
#define MC_INVALID_VAL64 ((uint64_t)-1)
#define MC_INVALID_VAL32 ((uint32_t)-1)
#define MC_INVALID_VAL8 ((uint8_t)-1)
#define MC_INVALID_VAL MC_INVALID_VAL32
/*
* 32 seem a good compromise for slot size
* 4 blocks are enough for the average passwd entry of 42 bytes
* passwd records have 84 bytes of overhead, 128 - 82 = 46 bytes
* 3 blocks can contain a very minimal entry, 96 - 82 = 14 bytes
*
* 3 blocks are enough for groups w/o users (private user groups)
* group records have 68 bytes of overhead, 96 - 66 = 30 bytes
*/
#define MC_SLOT_SIZE 32
#define MC_SIZE_TO_SLOTS(len) (((len) + (MC_SLOT_SIZE - 1)) / MC_SLOT_SIZE)
#define MC_PTR_TO_SLOT(base, ptr) (MC_PTR_DIFF(ptr, base) / MC_SLOT_SIZE)
#define MC_SLOT_TO_PTR(base, slot, type) \
(type *)((base) + ((slot) * MC_SLOT_SIZE))
#define MC_VALID_BARRIER(val) (((val) & 0xff000000) == 0xf0000000)
#define MC_CHECK_RECORD_LENGTH(mc_ctx, rec) \
((rec)->len >= MC_HEADER_SIZE && (rec)->len != MC_INVALID_VAL32 \
&& ((rec)->len <= ((mc_ctx)->dt_size \
- MC_PTR_DIFF(rec, (mc_ctx)->data_table))))
#define SSS_MC_MAJOR_VNO 0
#define SSS_MC_MINOR_VNO 4
#define SSS_MC_HEADER_UNINIT 0 /* after ftruncate or before reset */
#define SSS_MC_HEADER_ALIVE 1 /* current and in use */
#define SSS_MC_HEADER_RECYCLED 2 /* file was recycled, reopen asap */
#pragma pack(1)
struct sss_mc_header {
uint32_t b1; /* barrier 1 */
uint32_t major_vno; /* major version number */
uint32_t minor_vno; /* minor version number */
uint32_t status; /* database status */
uint32_t seed; /* random seed used to avoid collision attacks */
uint32_t dt_size; /* data table size */
uint32_t ft_size; /* free table size */
uint32_t ht_size; /* hash table size */
rel_ptr_t data_table; /* data table pointer relative to mmap base */
rel_ptr_t free_table; /* free table pointer relative to mmap base */
rel_ptr_t hash_table; /* hash table pointer relative to mmap base */
rel_ptr_t reserved; /* reserved for future changes */
uint32_t b2; /* barrier 2 */
};
struct sss_mc_rec {
uint32_t b1; /* barrier 1 */
uint32_t len; /* total record length including record data */
uint64_t expire; /* record expiration time (cast to time_t) */
rel_ptr_t next; /* ptr of next record rel to data_table */
uint32_t hash1; /* val of first hash (usually name of record) */
uint32_t hash2; /* val of second hash (usually id of record) */
uint32_t b2; /* barrier 2 - 32 bytes mark, fits a slot */
char data[0];
};
/* FIXME: Function sss_mc_find_record currently relies on fact that
* offset of strs is the same in both sss_mc_pwd_data and sss_mc_grp_data. */
struct sss_mc_pwd_data {
rel_ptr_t name; /* ptr to name string, rel. to struct base addr */
uint32_t uid;
uint32_t gid;
uint32_t strs_len; /* length of strs */
char strs[0]; /* concatenation of all passwd strings, each
* string is zero terminated ordered as follows:
* name, passwd, gecos, dir, shell */
};
struct sss_mc_grp_data {
rel_ptr_t name; /* ptr to name string, rel. to struct base addr */
uint32_t gid;
uint32_t members; /* number of members in strs */
uint32_t strs_len; /* length of strs */
char strs[0]; /* concatenation of all group strings, each
* string is zero terminated ordered as follows:
* name, passwd, member1, member2, ... */
};
#pragma pack()
#endif /* _MMAP_CACHE_H_ */
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