git.ozlabs.org Git - ccan/blob - ccan/tdb2/test/layout.c

   1 /* TDB tools to create various canned database layouts. */
   2 #include "layout.h"
   3 #include <stdlib.h>
   4 #include <string.h>
   5 #include <assert.h>
   6 #include "logging.h"
   7
   8 struct tdb_layout *new_tdb_layout(void)
   9 {
  10         struct tdb_layout *layout = malloc(sizeof(*layout));
  11         layout->num_elems = 0;
  12         layout->elem = NULL;
  13         return layout;
  14 }
  15
  16 static void add(struct tdb_layout *layout, union tdb_layout_elem elem)
  17 {
  18         layout->elem = realloc(layout->elem,
  19                                sizeof(layout->elem[0])
  20                                * (layout->num_elems+1));
  21         layout->elem[layout->num_elems++] = elem;
  22 }
  23
  24 void tdb_layout_add_zone(struct tdb_layout *layout,
  25                          unsigned int zone_bits,
  26                          bool fill_prev)
  27 {
  28         union tdb_layout_elem elem;
  29         if (fill_prev)
  30                 tdb_layout_add_free(layout, 0);
  31         elem.base.type = ZONE;
  32         elem.zone.zone_bits = zone_bits;
  33         add(layout, elem);
  34 }
  35
  36 void tdb_layout_add_free(struct tdb_layout *layout, tdb_len_t len)
  37 {
  38         union tdb_layout_elem elem;
  39         elem.base.type = FREE;
  40         elem.free.len = len;
  41         add(layout, elem);
  42 }
  43
  44 static struct tdb_data dup_key(struct tdb_data key)
  45 {
  46         struct tdb_data ret;
  47         ret.dsize = key.dsize;
  48         ret.dptr = malloc(ret.dsize);
  49         memcpy(ret.dptr, key.dptr, ret.dsize);
  50         return ret;
  51 }
  52
  53 void tdb_layout_add_used(struct tdb_layout *layout,
  54                          TDB_DATA key, TDB_DATA data,
  55                          tdb_len_t extra)
  56 {
  57         union tdb_layout_elem elem;
  58         elem.base.type = DATA;
  59         elem.used.key = dup_key(key);
  60         elem.used.data = dup_key(data);
  61         elem.used.extra = extra;
  62         add(layout, elem);
  63 }
  64
  65 static tdb_len_t free_record_len(tdb_len_t len)
  66 {
  67         return sizeof(struct tdb_used_record) + len;
  68 }
  69
  70 static tdb_len_t data_record_len(struct tle_used *used)
  71 {
  72         tdb_len_t len;
  73         len = sizeof(struct tdb_used_record)
  74                 + used->key.dsize + used->data.dsize + used->extra;
  75         assert(len >= sizeof(struct tdb_free_record));
  76         return len;
  77 }
  78
  79 static tdb_len_t hashtable_len(struct tle_hashtable *htable)
  80 {
  81         return sizeof(struct tdb_used_record)
  82                 + (sizeof(tdb_off_t) << TDB_SUBLEVEL_HASH_BITS)
  83                 + htable->extra;
  84 }
  85
  86 static tdb_len_t zone_header_len(struct tle_zone *zone)
  87 {
  88         return sizeof(struct free_zone_header)
  89                 + sizeof(tdb_off_t) * (BUCKETS_FOR_ZONE(zone->zone_bits)+1);
  90 }
  91
  92 static void set_free_record(void *mem, tdb_len_t len)
  93 {
  94         /* We do all the work in add_to_freetable */
  95 }
  96
  97 static void set_data_record(void *mem, struct tdb_context *tdb,
  98                             struct tle_zone *last_zone,
  99                             struct tle_used *used)
 100 {
 101         struct tdb_used_record *u = mem;
 102
 103         set_header(tdb, u, used->key.dsize, used->data.dsize,
 104                    used->key.dsize + used->data.dsize + used->extra,
 105                    tdb_hash(tdb, used->key.dptr, used->key.dsize),
 106                    last_zone->zone_bits);
 107         memcpy(u + 1, used->key.dptr, used->key.dsize);
 108         memcpy((char *)(u + 1) + used->key.dsize,
 109                used->data.dptr, used->data.dsize);
 110 }
 111
 112 static void set_hashtable(void *mem, struct tdb_context *tdb,
 113                           struct tle_zone *last_zone,
 114                           struct tle_hashtable *htable)
 115 {
 116         struct tdb_used_record *u = mem;
 117         tdb_len_t len = sizeof(tdb_off_t) << TDB_SUBLEVEL_HASH_BITS;
 118
 119         set_header(tdb, u, 0, len, len + htable->extra, 0,
 120                    last_zone->zone_bits);
 121         memset(u + 1, 0, len);
 122 }
 123
 124 static void set_zone(void *mem, struct tdb_context *tdb,
 125                      struct tle_zone *zone)
 126 {
 127         struct free_zone_header *fz = mem;
 128         memset(fz, 0, zone_header_len(zone));
 129         fz->zone_bits = zone->zone_bits;
 130 }
 131
 132 static void add_to_freetable(struct tdb_context *tdb,
 133                              struct tle_zone *last_zone,
 134                              tdb_off_t eoff,
 135                              tdb_off_t elen)
 136 {
 137         add_free_record(tdb, last_zone->zone_bits, eoff,
 138                         sizeof(struct tdb_used_record) + elen);
 139 }
 140
 141 static tdb_off_t hbucket_off(tdb_off_t group_start, unsigned ingroup)
 142 {
 143         return group_start
 144                 + (ingroup % (1 << TDB_HASH_GROUP_BITS)) * sizeof(tdb_off_t);
 145 }
 146
 147 /* Get bits from a value. */
 148 static uint32_t bits(uint64_t val, unsigned start, unsigned num)
 149 {
 150         assert(num <= 32);
 151         return (val >> start) & ((1U << num) - 1);
 152 }
 153
 154 /* We take bits from the top: that way we can lock whole sections of the hash
 155  * by using lock ranges. */
 156 static uint32_t use_bits(uint64_t h, unsigned num, unsigned *used)
 157 {
 158         *used += num;
 159         return bits(h, 64 - *used, num);
 160 }
 161
 162 static tdb_off_t encode_offset(tdb_off_t new_off, unsigned bucket,
 163                                uint64_t h)
 164 {
 165         return bucket
 166                 | new_off
 167                 | ((uint64_t)bits(h, 64 - TDB_OFF_UPPER_STEAL_EXTRA,
 168                                   TDB_OFF_UPPER_STEAL_EXTRA)
 169                    << TDB_OFF_HASH_EXTRA_BIT);
 170 }
 171
 172 /* FIXME: Our hash table handling here is primitive: we don't expand! */
 173 static void add_to_hashtable(struct tdb_context *tdb,
 174                              tdb_off_t eoff,
 175                              struct tdb_data key)
 176 {
 177         uint64_t h = tdb_hash(tdb, key.dptr, key.dsize);
 178         tdb_off_t b_off, group_start;
 179         unsigned i, group, in_group;
 180         unsigned used = 0;
 181
 182         group = use_bits(h, TDB_TOPLEVEL_HASH_BITS-TDB_HASH_GROUP_BITS, &used);
 183         in_group = use_bits(h, TDB_HASH_GROUP_BITS, &used);
 184
 185         group_start = offsetof(struct tdb_header, hashtable)
 186                 + group * (sizeof(tdb_off_t) << TDB_HASH_GROUP_BITS);
 187
 188         for (i = 0; i < (1 << TDB_HASH_GROUP_BITS); i++) {
 189                 unsigned bucket = (in_group + i) % (1 << TDB_HASH_GROUP_BITS);
 190
 191                 b_off = hbucket_off(group_start, bucket);
 192                 if (tdb_read_off(tdb, b_off) == 0) {
 193                         tdb_write_off(tdb, b_off,
 194                                       encode_offset(eoff, bucket, h));
 195                         return;
 196                 }
 197         }
 198         abort();
 199 }
 200
 201 /* FIXME: Support TDB_CONVERT */
 202 struct tdb_context *tdb_layout_get(struct tdb_layout *layout)
 203 {
 204         unsigned int i;
 205         tdb_off_t off, len;
 206         tdb_len_t zone_left;
 207         char *mem;
 208         struct tdb_context *tdb;
 209         struct tle_zone *last_zone = NULL;
 210
 211         assert(layout->elem[0].base.type == ZONE);
 212
 213         zone_left = 0;
 214         off = sizeof(struct tdb_header);
 215
 216         /* First pass of layout: calc lengths */
 217         for (i = 0; i < layout->num_elems; i++) {
 218                 union tdb_layout_elem *e = &layout->elem[i];
 219                 e->base.off = off;
 220                 switch (e->base.type) {
 221                 case ZONE:
 222                         assert(zone_left == 0);
 223                         len = zone_header_len(&e->zone);
 224                         zone_left = 1ULL << e->zone.zone_bits;
 225                         break;
 226                 case FREE:
 227                         if (e->free.len == 0)
 228                                 e->free.len = zone_left
 229                                         - sizeof(struct tdb_used_record);
 230                         len = free_record_len(e->free.len);
 231                         break;
 232                 case DATA:
 233                         len = data_record_len(&e->used);
 234                         break;
 235                 case HASHTABLE:
 236                         len = hashtable_len(&e->hashtable);
 237                         break;
 238                 }
 239                 off += len;
 240                 assert(zone_left >= len);
 241                 zone_left -= len;
 242         }
 243
 244         /* Fill final zone with free record. */
 245         if (zone_left != 0) {
 246                 tdb_layout_add_free(layout,
 247                                     zone_left
 248                                     - sizeof(struct tdb_used_record));
 249                 layout->elem[layout->num_elems-1].base.off = off;
 250                 off += zone_left;
 251         }
 252
 253         mem = malloc(off+1);
 254         /* Now populate our header, cribbing from a real TDB header. */
 255         tdb = tdb_open(NULL, TDB_INTERNAL, O_RDWR, 0, &tap_log_attr);
 256         memcpy(mem, tdb->map_ptr, sizeof(struct tdb_header));
 257
 258         /* Mug the tdb we have to make it use this. */
 259         free(tdb->map_ptr);
 260         tdb->map_ptr = mem;
 261         tdb->map_size = off+1;
 262
 263         for (i = 0; i < layout->num_elems; i++) {
 264                 union tdb_layout_elem *e = &layout->elem[i];
 265                 switch (e->base.type) {
 266                 case ZONE:
 267                         set_zone(mem + e->base.off, tdb, &e->zone);
 268                         last_zone = &e->zone;
 269                         break;
 270                 case FREE:
 271                         set_free_record(mem + e->base.off, e->free.len);
 272                         break;
 273                 case DATA:
 274                         set_data_record(mem + e->base.off, tdb, last_zone,
 275                                         &e->used);
 276                         break;
 277                 case HASHTABLE:
 278                         set_hashtable(mem + e->base.off, tdb, last_zone,
 279                                       &e->hashtable);
 280                         break;
 281                 }
 282         }
 283
 284         /* Now fill the free and hash tables. */
 285         for (i = 0; i < layout->num_elems; i++) {
 286                 union tdb_layout_elem *e = &layout->elem[i];
 287                 switch (e->base.type) {
 288                 case ZONE:
 289                         last_zone = &e->zone;
 290                         break;
 291                 case FREE:
 292                         add_to_freetable(tdb, last_zone,
 293                                          e->base.off, e->free.len);
 294                         break;
 295                 case DATA:
 296                         add_to_hashtable(tdb, e->base.off, e->used.key);
 297                         break;
 298                 default:
 299                         break;
 300                 }
 301         }
 302
 303         /* Write tailer. */
 304         ((uint8_t *)tdb->map_ptr)[tdb->map_size-1] = last_zone->zone_bits;
 305         return tdb;
 306 }