osl_core.h

   1 /*
   2  * Copyright (C) 2007 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file osl_core.h Object storage layer details, not visible to users. */
   8
   9 #include "rbtree.h"
  10 #include "osl.h"
  11 #include "string.h"
  12 #include "hash.h"
  13
  14 /** Internal representation of a column of an osl table. */
  15 struct osl_column {
  16         /** The memory mapping of this comumn (only used for mapped columns). */
  17         struct osl_object data_map;
  18         /** The root of the rbtree (only used for columns with rbtrees). */
  19         struct rb_root rbtree;
  20         /** The index in the array of rb nodes (only used for columns with rbtrees). */
  21         unsigned rbtree_num;
  22         /** Index for volatile_objects of struct osl_row. */
  23         unsigned volatile_num;
  24         /**
  25          * Starting point of the data for this column within the index
  26          * (only used for mapped columns).
  27          */
  28         uint16_t index_offset;
  29         /**
  30          * The hash value of the name of this column.
  31          *
  32          * This is only used for mapped and disk storage columns).
  33          */
  34         HASH_TYPE name_hash[HASH_SIZE];
  35 };
  36
  37 /** Internal representation of an osl table */
  38 struct osl_table {
  39         /** Pointer to the table description */
  40         const struct osl_table_description *desc;
  41         /** The size of the index header of this table. */
  42         uint16_t index_header_size;
  43         /** Contains the mapping of the table's index file */
  44         struct osl_object index_map;
  45         /** Total number of rows, including invalid rows. */
  46         unsigned num_rows;
  47         /** Keeps track of the number of invalid rows in the table. */
  48         uint32_t num_invalid_rows;
  49         /** Number of columns of type \p OSL_MAPPED_STORAGE. */
  50         unsigned num_mapped_columns;
  51         /** Number of columns of type \p OSL_NO_STORAGE. */
  52         unsigned num_volatile_columns;
  53         /** Number of columns of type \p OSL_DISK_STORAGE. */
  54         unsigned num_disk_storage_columns;
  55         /** Number of columns with associated rbtree. */
  56         unsigned num_rbtrees;
  57         /**
  58          * The number of the column that determines the name of the disk
  59          * storage objcts.
  60          */
  61         unsigned disk_storage_name_column;
  62         /** The number of bytes of an index entry of a row. */
  63         unsigned row_index_size;
  64         /** Pointer to the internal representation of the columns. */
  65         struct osl_column *columns;
  66 };
  67
  68 /** Internal representation of a row of an osl table */
  69 struct osl_row {
  70         /**
  71          * The row number.
  72          *
  73          * It is only used if there is at least one mapped column.
  74          */
  75         off_t num;
  76         /** Array of size \a num_volatile_columns. */
  77         struct osl_object *volatile_objects;
  78 };
  79
  80 int read_table_desc(struct osl_object *map, struct osl_table_description *desc);
  81 int init_table_structure(const struct osl_table_description *desc,
  82                 struct osl_table **table_ptr);
  83 int row_is_invalid(struct osl_table *t, uint32_t row_num);
  84 int get_mapped_object(const struct osl_table *t, unsigned col_num,
  85         uint32_t row_num, struct osl_object *obj);
  86 int para_truncate(const char *filename, off_t size);
  87 int unmap_table(struct osl_table *t, enum osl_close_flags flags);
  88 int init_rbtrees(struct osl_table *t);
  89
  90 /**
  91  * Flags to be specified for map_table().
  92  *
  93  * \sa map_table().
  94  */
  95 enum map_table_flags {
  96         /**
  97          * Check whether the entries in the table index match the entries in
  98          * the table desctiption.
  99          */
 100         MAP_TBL_FL_VERIFY_INDEX = 1,
 101         /** Do not complain even if the dirty flag is set. */
 102         MAP_TBL_FL_IGNORE_DIRTY = 2,
 103         /** Use read-only mappings. */
 104         MAP_TBL_FL_MAP_RDONLY = 4
 105 };
 106
 107 int map_table(struct osl_table *t, enum map_table_flags flags);
 108 void clear_rbtrees(struct osl_table *t);
 109 int mark_row_invalid(struct osl_table *t, uint32_t row_num);
 110
 111
 112 /**
 113  * Get the description of a column by column number
 114  *
 115  * \param d Pointer to the table description.
 116  * \param col_num The number of the column to get the desctiption for.
 117  *
 118  * \return The table description.
 119  *
 120  * \sa struct osl_column_description.
 121  */
 122 _static_inline_ struct osl_column_description *get_column_description(
 123                 const struct osl_table_description *d, unsigned col_num)
 124 {
 125         return &d->column_descriptions[col_num];
 126 }
 127
 128 /**
 129  * Format of the header of the index file of an osl table.
 130  *
 131  * Bytes 16-31 are currently unused.
 132  *
 133  * \sa enum index_column_desc_offsets, HASH_SIZE, osl_table_flags.
 134  */
 135 enum index_header_offsets {
 136         /** Bytes 0-8: PARASLASH. */
 137         IDX_PARA_MAGIC = 0,
 138         /** Byte 9: Dirty flag (nonzero if table is mapped). */
 139         IDX_DIRTY_FLAG = 9,
 140         /** Byte 10: osl table version number. */
 141         IDX_VERSION = 10,
 142         /** Byte 11: Table flags.*/
 143         IDX_TABLE_FLAGS = 11,
 144         /** Byte 12,13: Number of columns. */
 145         IDX_NUM_COLUMNS,
 146         /** Byte 14,15 Size of the index header. */
 147         IDX_HEADER_SIZE = 14,
 148         /** Column descriptions start here. */
 149         IDX_COLUMN_DESCRIPTIONS = 32
 150 };
 151
 152 /**
 153  * Format of the column description in the index header.
 154  *
 155  * \sa index_header_offsets.
 156  */
 157 enum index_column_desc_offsets {
 158         /** Bytes 0,1: Storage_type. */
 159         IDX_CD_STORAGE_TYPE = 0,
 160         /** Bytes 2,3: Storage_flags. */
 161         IDX_CD_STORAGE_FLAGS = 2,
 162         /** Bytes 4 - 7: Data_size (only used for fixed size columns). */
 163         IDX_CD_DATA_SIZE = 4,
 164         /** Bytes 8 - ... Name of the column. */
 165         IDX_CD_NAME = 8,
 166 };
 167
 168 /** Magic string contained in the header of the index file of each osl table. */
 169 #define PARA_MAGIC "PARASLASH"
 170
 171 /**
 172  * The minimal number of bytes for a column in the index header.
 173  *
 174  * The column name starts at byte IDX_CD_NAME and must at least contain one
 175  * character, plus the terminating NULL byte.
 176   */
 177 #define MIN_IDX_COLUMN_DESCRIPTION_SIZE (IDX_CD_NAME + 2)
 178
 179 /**
 180  * Get the number of bytes used for a column in the index header.
 181  *
 182  * \param name The name of the column.
 183  *
 184  * The amount of space used for a column in the index header of a table depends
 185  * on the (length of the) name of the column.
 186  *
 187  * \return The total number of bytes needed to store one column of this name.
 188  */
 189 _static_inline_ size_t index_column_description_size(const char *name)
 190 {
 191         return MIN_IDX_COLUMN_DESCRIPTION_SIZE + strlen(name) - 1;
 192 }
 193
 194 #define CURRENT_TABLE_VERSION 1
 195 #define MIN_TABLE_VERSION 1
 196 #define MAX_TABLE_VERSION 1
 197 /** An index header must be at least that many bytes long. */
 198 #define MIN_INDEX_HEADER_SIZE(num_cols) (MIN_IDX_COLUMN_DESCRIPTION_SIZE \
 199         * num_cols + IDX_COLUMN_DESCRIPTIONS)
 200
 201 /**
 202  * Get the number of rows from the size of the memory mapping.
 203  *
 204  * \param t Pointer to an open table.
 205  *
 206  * \return The number of rows, including invalid rows.
 207  */
 208 _static_inline_ unsigned table_num_rows(const struct osl_table *t)
 209 {
 210         return (t->index_map.size - t->index_header_size)
 211                 / t->row_index_size;
 212 }
 213
 214 /**
 215  * Get the path of the index file from a table description.
 216  *
 217  * \param d The table description.
 218  *
 219  * \return The full path of the index file. Result must be freed by
 220  * the caller.
 221  */
 222 _static_inline_ char *index_filename(const struct osl_table_description *d)
 223 {
 224         return make_message("%s/%s/index", d->dir, d->name);
 225 }
 226
 227 /**
 228  * Get the path of storage of a column.
 229  *
 230  * \param t Pointer to an initialized table.
 231  * \param col_num The number of the column to get the path for.
 232  *
 233  * \return The full path of the mapped data file (mapped storage) or the
 234  * data directory (disk storage). Result must be freed by the caller.
 235  *
 236  * \sa osl_storage_type.
 237  */
 238 _static_inline_ char *column_filename(const struct osl_table *t, unsigned col_num)
 239 {
 240         char asc[2 * HASH_SIZE + 1];
 241         hash_to_asc(t->columns[col_num].name_hash, asc);
 242         return make_message("%s/%s/%s", t->desc->dir, t->desc->name, asc);
 243 }
 244
 245 /**
 246  * Get the start of an index entry
 247  *
 248  * \param t Pointer to a table which has been mapped.
 249  * \param row_num The number of the row whose index entry should be retrieved.
 250  * \param row_index Result pointer.
 251  *
 252  * \return Positive on success, \p -E_INDEX_CORRUPTION otherwise.
 253  *
 254  * \sa get_cell_index().
 255  */
 256 _static_inline_ int get_row_index(const struct osl_table *t, uint32_t row_num,
 257                 char **row_index)
 258 {
 259         uint32_t index_offset;
 260         index_offset = t->index_header_size + t->row_index_size * row_num;
 261         if (index_offset + 8 > t->index_map.size) {
 262                 *row_index = NULL;
 263                 return -E_INDEX_CORRUPTION;
 264         }
 265         *row_index = (char *)(t->index_map.data) + index_offset;
 266         return 1;
 267 }
 268
 269 /**
 270  * Get the index entry of a row/column pair.
 271  *
 272  * \param t Pointer to a table which has been mapped.
 273  * \param row_num The number of the row whose index entry should be retrieved.
 274  * \param col_num The number of the column whose index entry should be retrieved.
 275  * \param cell_index Result pointer.
 276  *
 277  * \return Positive on success, \p -E_INDEX_CORRUPTION otherwise.
 278  *
 279  * \sa get_row_index().
 280  */
 281 _static_inline_ int get_cell_index(const struct osl_table *t, uint32_t row_num,
 282                 uint32_t col_num, char **cell_index)
 283 {
 284         int ret = get_row_index(t, row_num, cell_index);
 285         if (ret < 0)
 286                 return ret;
 287         *cell_index += t->columns[col_num].index_offset;
 288         return ret;
 289 }
 290
 291 /**
 292  * Change an index entry of a column after object was added.
 293  *
 294  * \param row_index Pointer to the index of the row to update.
 295  * \param col Pointer to the column.
 296  * \param map_size The new size of the data file.
 297  * \param object_size The size of the object just appended to the data file.
 298  *
 299  * This is called right after an object was appended to the data file for a
 300  * mapped column.
 301  *
 302  * \sa get_row_index().
 303  */
 304 _static_inline_ void update_cell_index(char *row_index, struct osl_column *col,
 305                 uint32_t map_size, uint32_t object_size)
 306 {
 307         write_u32(row_index + col->index_offset, map_size - object_size - 1);
 308         write_u32(row_index + col->index_offset + 4, object_size + 1);
 309 }
 310
 311 /**
 312  * Get the full path of a disk storage object
 313  *
 314  * \param t Pointer to an initialized table.
 315  * \param col_num The number of the column the disk storage object belongs to.
 316  * \param ds_name The disk storage name of the object.
 317  *
 318  * \return Pointer to the full path which must be freed by the caller.
 319  *
 320  * \sa column_filename(), disk_storage_name_of_row().
 321  */
 322 _static_inline_ char *disk_storage_path(const struct osl_table *t,
 323                 unsigned col_num, const char *ds_name)
 324 {
 325         char *dirname = column_filename(t, col_num);
 326         char *filename = make_message("%s/%s", dirname, ds_name);
 327         free(dirname);
 328         return filename;
 329 }
 330
 331 /**
 332  * Get the column description of the next column of a given type.
 333  *
 334  * \param type the desired storage type.
 335  * \param col_num the column to start the search.
 336  * \param t the osl table.
 337  * \param cd result is returned here.
 338  *
 339  * \return On success, \a cd contains the column description of the next column
 340  * of type \a type, and the number of that column is returned.  Otherwise, \a
 341  * cd is set to \p NULL and the function returns t->num_columns + 1.
 342  *
 343  * \sa FOR_EACH_COLUMN_OF_TYPE, FOR_EACH_MAPPED_COLUMN, FOR_EACH_RBTREE_COLUMN,
 344  * FOR_EACH_DISK_STORAGE_COLUMN, FOR_EACH_VOLATILE_COLUMN, osl_storage_type.
 345  */
 346 _static_inline_ int next_column_of_type(enum osl_storage_type type, int col_num,
 347                 const struct osl_table *t,
 348                 const struct osl_column_description **cd)
 349 {
 350         *cd = NULL;
 351         while (col_num < t->desc->num_columns) {
 352                 *cd = get_column_description(t->desc, col_num);
 353                 if ((*cd)->storage_type == type)
 354                         break;
 355                 col_num++;
 356         }
 357         return col_num;
 358 }
 359
 360 /**
 361  * Find the next column with an associated rbtree.
 362  *
 363  * \param col_num The column to start the search.
 364  * \param t The osl table.
 365  * \param cd Result is returned here.
 366
 367  * \return On success, \a cd contains the column description of the next column
 368  * with associated rbtree, and the number of that column is returned.
 369  * Otherwise, \a cd is set to \p NULL and the function returns t->num_columns +
 370  * 1.
 371  *
 372  * \sa FOR_EACH_COLUMN_OF_TYPE, FOR_EACH_MAPPED_COLUMN, FOR_EACH_RBTREE_COLUMN,
 373  * FOR_EACH_DISK_STORAGE_COLUMN, FOR_EACH_VOLATILE_COLUMN, osl_storage_flags.
 374  */
 375 _static_inline_ int next_rbtree_column(int col_num, const struct osl_table *t,
 376                 const struct osl_column_description **cd)
 377 {
 378         *cd = NULL;
 379         while (col_num < t->desc->num_columns) {
 380                 *cd = get_column_description(t->desc, col_num);
 381                 if ((*cd)->storage_flags & OSL_RBTREE)
 382                         break;
 383                 col_num++;
 384         }
 385         return col_num;
 386 }
 387
 388
 389 /* quite some dirty hacks */
 390
 391 /** Round up size of struct osl_row to multiple of 8 */
 392 #define RB_NODES_OFFSET ((sizeof(struct osl_row) + 7) / 8 * 8)
 393
 394 /**
 395  * Allocate a new osl row.
 396  *
 397  * \param num_rbtrees The number of rbtrees for this row.
 398  *
 399  * \return A pointer to a zeroed-out area suitable for holding an osl row
 400  * with \a num_rbtrees rbtree columns.
 401  */
 402 _static_inline_ struct osl_row *allocate_row(unsigned num_rbtrees)
 403 {
 404         size_t s = RB_NODES_OFFSET + num_rbtrees * sizeof(struct rb_node);
 405         return para_calloc(s);
 406 }
 407
 408 /**
 409  * Compute the pointer to a rbtree node embedded in a osl row.
 410  *
 411  * \param row The row to extract the rbtree pointer from.
 412  * \param rbtree_num The number of the rbtree node to extract.
 413  *
 414  * \return A pointer to the \a rbtree_num th node contained in \a row.
 415  */
 416 _static_inline_ struct rb_node *get_rb_node_pointer(const struct osl_row *row, uint32_t rbtree_num)
 417 {
 418         return ((struct rb_node *)(((char *)row) + RB_NODES_OFFSET)) + rbtree_num;
 419 }
 420
 421 /**
 422  * Get a pointer to the struct containing the given rbtree node.
 423  *
 424  * \param node Pointer to the rbtree node.
 425  * \param rbtree_num Number of \a node in the array of rbtree nodes.
 426  *
 427  * \return A pointer to the row containing \a node.
 428  */
 429 _static_inline_ struct osl_row *get_row_pointer(const struct rb_node *node,
 430                 unsigned rbtree_num)
 431 {
 432         node -= rbtree_num;
 433         return (struct osl_row *)(((char *)node) - RB_NODES_OFFSET);
 434 }
 435
 436 /**
 437  * Compute a cryptographic hash of an osl object.
 438  *
 439  * \param obj the Object to compute the hash value from.
 440  * \param hash Result is returned here.
 441  */
 442 static inline void hash_object(const struct osl_object *obj, HASH_TYPE *hash)
 443 {
 444         return hash_function(obj->data, obj->size, hash);
 445 }
 446
 447 /**
 448  * Get the relative path of an object, given the hash value.
 449  *
 450  * \param t Pointer to an initialized osl table.
 451  * \param hash An arbitrary hash value.
 452  *
 453  * This function is typically called with \a hash being the hash of the object
 454  * stored in the disk storage name column of a row.  If the OSL_LARGE_TABLE
 455  * flag is set, the first two hex digits get separated with a slash from the
 456  * remaining digits.
 457  *
 458  * \return The relative path for all disk storage objects corresponding to \a
 459  * hash.
 460  *
 461  * \sa struct osl_table:disk_storage_name_column.
 462  */
 463 static inline char *disk_storage_name_of_hash(const struct osl_table *t, HASH_TYPE *hash)
 464 {
 465         char asc[2 * HASH_SIZE + 2];
 466
 467         hash_to_asc(hash, asc);
 468         if (t->desc->flags & OSL_LARGE_TABLE)
 469                 return make_message("%.2s/%s", asc, asc + 2);
 470         return para_strdup(asc);
 471 }
 472
 473 /**
 474  * A wrapper for rename(2).
 475  *
 476  * \param old_path The source path.
 477  * \param new_path The destination path.
 478  *
 479  * \return positive in success, \p -E_RENAME on errors.
 480  *
 481  * \sa rename(2).
 482  */
 483 static inline int para_rename(const char *old_path, const char *new_path)
 484 {
 485         if (rename(old_path, new_path) < 0)
 486                 return -E_RENAME;
 487         return 1;
 488 }
 489
 490 /**
 491  * Iterate over each column of an initialized table.
 492  *
 493  * \param col A pointer to a struct osl_column.
 494  * \param desc Pointer to the table description.
 495  * \param cd Pointer to struct osl_column_description.
 496  *
 497  * On each iteration, \a col will point to the next column of the table and \a
 498  * cd will point to the column description of this column.
 499  *
 500  * \sa struct osl_column FOR_EACH_RBTREE_COLUMN, FOR_EACH_COLUMN_OF_TYPE,
 501  * FOR_EACH_MAPPED_COLUMN, FOR_EACH_DISK_STORAGE_COLUMN,
 502  * FOR_EACH_VOLATILE_COLUMN.
 503  */
 504 #define FOR_EACH_COLUMN(col, desc, cd) \
 505         for (col = 0; col < (desc)->num_columns && \
 506                 (cd = get_column_description(desc, col)); col++)
 507
 508 /**
 509  * Iterate over each column with associated rbtree.
 510  *
 511  * \param col Same meaning as in FOR_EACH_COLUMN().
 512  * \param table Same meaning as in FOR_EACH_COLUMN().
 513  * \param cd Same meaning as in FOR_EACH_COLUMN().
 514  *
 515  * \sa osl_storage_flags::OSL_RBTREE, FOR_EACH_COLUMN, FOR_EACH_COLUMN_OF_TYPE,
 516  * FOR_EACH_MAPPED_COLUMN, FOR_EACH_DISK_STORAGE_COLUMN,
 517  * FOR_EACH_VOLATILE_COLUMN.
 518  */
 519 #define FOR_EACH_RBTREE_COLUMN(col, table, cd) \
 520         for (col = next_rbtree_column(0, table, &cd); \
 521         col < table->desc->num_columns; \
 522         col = next_rbtree_column(++col, table, &cd))
 523
 524 /**
 525  * Iterate over each column of given storage type.
 526  *
 527  * \param type The osl_storage_type to iterate over.
 528  * \param col Same meaning as in FOR_EACH_COLUMN().
 529  * \param table Same meaning as in FOR_EACH_COLUMN().
 530  * \param cd Same meaning as in FOR_EACH_COLUMN().
 531  *
 532  * \sa osl_storage_type, FOR_EACH_COLUMN, FOR_EACH_RBTREE_COLUMN,
 533  * FOR_EACH_MAPPED_COLUMN, FOR_EACH_DISK_STORAGE_COLUMN,
 534  * FOR_EACH_VOLATILE_COLUMN.
 535  */
 536 #define FOR_EACH_COLUMN_OF_TYPE(type, col, table, cd) \
 537         for (col = next_column_of_type(type, 0, table, &cd); \
 538         col < table->desc->num_columns; \
 539         col = next_column_of_type(type, ++col, table, &cd))
 540
 541 /**
 542  * Iterate over each mapped column.
 543  *
 544  * \param col Same meaning as in FOR_EACH_COLUMN().
 545  * \param table Same meaning as in FOR_EACH_COLUMN().
 546  * \param cd Same meaning as in FOR_EACH_COLUMN().
 547  *
 548  * Just like FOR_EACH_COLUMN(), but skip columns which are
 549  * not of type \p OSL_MAPPED_STORAGE.
 550  *
 551  * \sa osl_storage_flags::OSL_MAPPED_STORAGE, FOR_EACH_COLUMN,
 552  * FOR_EACH_RBTREE_COLUMN, FOR_EACH_COLUMN_OF_TYPE,
 553  * FOR_EACH_DISK_STORAGE_COLUMN, FOR_EACH_VOLATILE_COLUMN.
 554  */
 555 #define FOR_EACH_MAPPED_COLUMN(col, table, cd) \
 556         FOR_EACH_COLUMN_OF_TYPE(OSL_MAPPED_STORAGE, col, table, cd)
 557
 558 /**
 559  * Iterate over each disk storage column.
 560  *
 561  * \param col Same meaning as in FOR_EACH_COLUMN().
 562  * \param table Same meaning as in FOR_EACH_COLUMN().
 563  * \param cd Same meaning as in FOR_EACH_COLUMN().
 564  *
 565  * Just like FOR_EACH_COLUMN(), but skip columns which are
 566  * not of type \p OSL_DISK_STORAGE.
 567  *
 568  * \sa osl_storage_flags::OSL_DISK_STORAGE, FOR_EACH_COLUMN,
 569  * FOR_EACH_RBTREE_COLUMN, FOR_EACH_COLUMN_OF_TYPE, FOR_EACH_MAPPED_COLUMN,
 570  * FOR_EACH_VOLATILE_COLUMN.
 571  */
 572 #define FOR_EACH_DISK_STORAGE_COLUMN(col, table, cd) \
 573         FOR_EACH_COLUMN_OF_TYPE(OSL_DISK_STORAGE, col, table, cd)
 574
 575 /**
 576  * Iterate over each volatile column.
 577  *
 578  * \param col Same meaning as in FOR_EACH_COLUMN().
 579  * \param table Same meaning as in FOR_EACH_COLUMN().
 580  * \param cd Same meaning as in FOR_EACH_COLUMN().
 581  *
 582  * Just like FOR_EACH_COLUMN(), but skip columns which are
 583  * not of type \p OSL_NO_STORAGE.
 584  *
 585  * \sa osl_storage_flags::OSL_NO_STORAGE, FOR_EACH_COLUMN,
 586  * FOR_EACH_RBTREE_COLUMN, FOR_EACH_COLUMN_OF_TYPE, FOR_EACH_MAPPED_COLUMN,
 587  * FOR_EACH_DISK_STORAGE_COLUMN.
 588  */
 589 #define FOR_EACH_VOLATILE_COLUMN(col, table, cd) \
 590         FOR_EACH_COLUMN_OF_TYPE(OSL_NO_STORAGE, col, table, cd)