diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/util/mmap_cache.h | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/src/util/mmap_cache.h b/src/util/mmap_cache.h new file mode 100644 index 00000000..0a4044a7 --- /dev/null +++ b/src/util/mmap_cache.h @@ -0,0 +1,117 @@ +/* + 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_PTR (void *)0xffffffff +#define MC_INVALID_VAL 0xffffffff + +/* + * 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_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]; +}; + +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 */ +}; +#pragma pack() + + +#endif /* _MMAP_CACHE_H_ */ |