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 <err.h>
   7 #include "logging.h"
   8
   9 struct tdb_layout *new_tdb_layout(const char *filename)
  10 {
  11         struct tdb_layout *layout = malloc(sizeof(*layout));
  12         layout->filename = filename;
  13         layout->num_elems = 0;
  14         layout->elem = NULL;
  15         return layout;
  16 }
  17
  18 static void add(struct tdb_layout *layout, union tdb_layout_elem elem)
  19 {
  20         layout->elem = realloc(layout->elem,
  21                                sizeof(layout->elem[0])
  22                                * (layout->num_elems+1));
  23         layout->elem[layout->num_elems++] = elem;
  24 }
  25
  26 void tdb_layout_add_freelist(struct tdb_layout *layout)
  27 {
  28         union tdb_layout_elem elem;
  29         elem.base.type = FREELIST;
  30         add(layout, elem);
  31 }
  32
  33 void tdb_layout_add_free(struct tdb_layout *layout, tdb_len_t len)
  34 {
  35         union tdb_layout_elem elem;
  36         elem.base.type = FREE;
  37         elem.free.len = len;
  38         add(layout, elem);
  39 }
  40
  41 static struct tdb_data dup_key(struct tdb_data key)
  42 {
  43         struct tdb_data ret;
  44         ret.dsize = key.dsize;
  45         ret.dptr = malloc(ret.dsize);
  46         memcpy(ret.dptr, key.dptr, ret.dsize);
  47         return ret;
  48 }
  49
  50 void tdb_layout_add_used(struct tdb_layout *layout,
  51                          TDB_DATA key, TDB_DATA data,
  52                          tdb_len_t extra)
  53 {
  54         union tdb_layout_elem elem;
  55         elem.base.type = DATA;
  56         elem.used.key = dup_key(key);
  57         elem.used.data = dup_key(data);
  58         elem.used.extra = extra;
  59         add(layout, elem);
  60 }
  61
  62 static tdb_len_t free_record_len(tdb_len_t len)
  63 {
  64         return sizeof(struct tdb_used_record) + len;
  65 }
  66
  67 static tdb_len_t data_record_len(struct tle_used *used)
  68 {
  69         tdb_len_t len;
  70         len = sizeof(struct tdb_used_record)
  71                 + used->key.dsize + used->data.dsize + used->extra;
  72         assert(len >= sizeof(struct tdb_free_record));
  73         return len;
  74 }
  75
  76 static tdb_len_t hashtable_len(struct tle_hashtable *htable)
  77 {
  78         return sizeof(struct tdb_used_record)
  79                 + (sizeof(tdb_off_t) << TDB_SUBLEVEL_HASH_BITS)
  80                 + htable->extra;
  81 }
  82
  83 static tdb_len_t freelist_len(struct tle_freelist *flist)
  84 {
  85         return sizeof(struct tdb_freelist);
  86 }
  87
  88 static void set_free_record(void *mem, tdb_len_t len)
  89 {
  90         /* We do all the work in add_to_freetable */
  91 }
  92
  93 static void set_data_record(void *mem, struct tdb_context *tdb,
  94                             struct tle_used *used)
  95 {
  96         struct tdb_used_record *u = mem;
  97
  98         set_header(tdb, u, used->key.dsize, used->data.dsize,
  99                    used->key.dsize + used->data.dsize + used->extra,
 100                    tdb_hash(tdb, used->key.dptr, used->key.dsize));
 101         memcpy(u + 1, used->key.dptr, used->key.dsize);
 102         memcpy((char *)(u + 1) + used->key.dsize,
 103                used->data.dptr, used->data.dsize);
 104 }
 105
 106 static void set_hashtable(void *mem, struct tdb_context *tdb,
 107                           struct tle_hashtable *htable)
 108 {
 109         struct tdb_used_record *u = mem;
 110         tdb_len_t len = sizeof(tdb_off_t) << TDB_SUBLEVEL_HASH_BITS;
 111
 112         set_header(tdb, u, 0, len, len + htable->extra, 0);
 113         memset(u + 1, 0, len);
 114 }
 115
 116 static void set_freelist(void *mem, struct tdb_context *tdb,
 117                          struct tle_freelist *freelist)
 118 {
 119         struct tdb_freelist *flist = mem;
 120         memset(flist, 0, sizeof(*flist));
 121         set_header(tdb, &flist->hdr, 0,
 122                    sizeof(*flist) - sizeof(flist->hdr),
 123                    sizeof(*flist) - sizeof(flist->hdr), 1);
 124 }
 125
 126 static void add_to_freetable(struct tdb_context *tdb,
 127                              tdb_off_t eoff,
 128                              tdb_off_t elen)
 129 {
 130         add_free_record(tdb, eoff, sizeof(struct tdb_used_record) + elen);
 131 }
 132
 133 static tdb_off_t hbucket_off(tdb_off_t group_start, unsigned ingroup)
 134 {
 135         return group_start
 136                 + (ingroup % (1 << TDB_HASH_GROUP_BITS)) * sizeof(tdb_off_t);
 137 }
 138
 139 /* Get bits from a value. */
 140 static uint32_t bits(uint64_t val, unsigned start, unsigned num)
 141 {
 142         assert(num <= 32);
 143         return (val >> start) & ((1U << num) - 1);
 144 }
 145
 146 /* We take bits from the top: that way we can lock whole sections of the hash
 147  * by using lock ranges. */
 148 static uint32_t use_bits(uint64_t h, unsigned num, unsigned *used)
 149 {
 150         *used += num;
 151         return bits(h, 64 - *used, num);
 152 }
 153
 154 static tdb_off_t encode_offset(tdb_off_t new_off, unsigned bucket,
 155                                uint64_t h)
 156 {
 157         return bucket
 158                 | new_off
 159                 | ((uint64_t)bits(h, 64 - TDB_OFF_UPPER_STEAL_EXTRA,
 160                                   TDB_OFF_UPPER_STEAL_EXTRA)
 161                    << TDB_OFF_HASH_EXTRA_BIT);
 162 }
 163
 164 /* FIXME: Our hash table handling here is primitive: we don't expand! */
 165 static void add_to_hashtable(struct tdb_context *tdb,
 166                              tdb_off_t eoff,
 167                              struct tdb_data key)
 168 {
 169         uint64_t h = tdb_hash(tdb, key.dptr, key.dsize);
 170         tdb_off_t b_off, group_start;
 171         unsigned i, group, in_group;
 172         unsigned used = 0;
 173
 174         group = use_bits(h, TDB_TOPLEVEL_HASH_BITS-TDB_HASH_GROUP_BITS, &used);
 175         in_group = use_bits(h, TDB_HASH_GROUP_BITS, &used);
 176
 177         group_start = offsetof(struct tdb_header, hashtable)
 178                 + group * (sizeof(tdb_off_t) << TDB_HASH_GROUP_BITS);
 179
 180         for (i = 0; i < (1 << TDB_HASH_GROUP_BITS); i++) {
 181                 unsigned bucket = (in_group + i) % (1 << TDB_HASH_GROUP_BITS);
 182
 183                 b_off = hbucket_off(group_start, bucket);
 184                 if (tdb_read_off(tdb, b_off) == 0) {
 185                         tdb_write_off(tdb, b_off,
 186                                       encode_offset(eoff, bucket, h));
 187                         return;
 188                 }
 189         }
 190         abort();
 191 }
 192
 193 /* FIXME: Support TDB_CONVERT */
 194 struct tdb_context *tdb_layout_get(struct tdb_layout *layout)
 195 {
 196         unsigned int i;
 197         tdb_off_t off, len, flist_off = 0;
 198         char *mem;
 199         struct tdb_context *tdb;
 200
 201         off = sizeof(struct tdb_header);
 202
 203         /* First pass of layout: calc lengths */
 204         for (i = 0; i < layout->num_elems; i++) {
 205                 union tdb_layout_elem *e = &layout->elem[i];
 206                 e->base.off = off;
 207                 switch (e->base.type) {
 208                 case FREELIST:
 209                         assert(flist_off == 0);
 210                         flist_off = off;
 211                         len = freelist_len(&e->flist);
 212                         break;
 213                 case FREE:
 214                         len = free_record_len(e->free.len);
 215                         break;
 216                 case DATA:
 217                         len = data_record_len(&e->used);
 218                         break;
 219                 case HASHTABLE:
 220                         len = hashtable_len(&e->hashtable);
 221                         break;
 222                 default:
 223                         abort();
 224                 }
 225                 off += len;
 226         }
 227         /* Must have a free list! */
 228         assert(flist_off);
 229
 230         mem = malloc(off);
 231         /* Now populate our header, cribbing from a real TDB header. */
 232         tdb = tdb_open(NULL, TDB_INTERNAL, O_RDWR, 0, &tap_log_attr);
 233         memcpy(mem, tdb->map_ptr, sizeof(struct tdb_header));
 234
 235         /* Mug the tdb we have to make it use this. */
 236         free(tdb->map_ptr);
 237         tdb->map_ptr = mem;
 238         tdb->map_size = off;
 239         tdb->flist_off = flist_off;
 240
 241         for (i = 0; i < layout->num_elems; i++) {
 242                 union tdb_layout_elem *e = &layout->elem[i];
 243                 switch (e->base.type) {
 244                 case FREELIST:
 245                         set_freelist(mem + e->base.off, tdb, &e->flist);
 246                         break;
 247                 case FREE:
 248                         set_free_record(mem + e->base.off, e->free.len);
 249                         break;
 250                 case DATA:
 251                         set_data_record(mem + e->base.off, tdb, &e->used);
 252                         break;
 253                 case HASHTABLE:
 254                         set_hashtable(mem + e->base.off, tdb, &e->hashtable);
 255                         break;
 256                 }
 257         }
 258
 259         /* Now fill the free and hash tables. */
 260         for (i = 0; i < layout->num_elems; i++) {
 261                 union tdb_layout_elem *e = &layout->elem[i];
 262                 switch (e->base.type) {
 263                 case FREE:
 264                         add_to_freetable(tdb, e->base.off, e->free.len);
 265                         break;
 266                 case DATA:
 267                         add_to_hashtable(tdb, e->base.off, e->used.key);
 268                         break;
 269                 default:
 270                         break;
 271                 }
 272         }
 273
 274         /* Get physical if they asked for it. */
 275         if (layout->filename) {
 276                 int fd = open(layout->filename, O_WRONLY|O_TRUNC|O_CREAT,
 277                               0600);
 278                 if (fd < 0)
 279                         err(1, "opening %s for writing", layout->filename);
 280                 if (write(fd, tdb->map_ptr, tdb->map_size) != tdb->map_size)
 281                         err(1, "writing %s", layout->filename);
 282                 close(fd);
 283                 tdb_close(tdb);
 284                 /* NOMMAP is for lockcheck. */
 285                 tdb = tdb_open(layout->filename, TDB_NOMMAP, O_RDWR, 0,
 286                                &tap_log_attr);
 287         }
 288
 289         return tdb;
 290 }