/* SSSD Mmap Cache Common header Copyright (C) Simo Sorce 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 . */ #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) \ (((uint8_t *)(ptr) - (uint8_t *)(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 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_ */