Initial git checkin.
[adu.git] / osl.c
1 /*
2 * Copyright (C) 2007-2008 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file osl.c Object storage layer functions. */
8 #include <dirent.h> /* readdir() */
9 #include <assert.h>
10
11
12 #include "adu.h"
13 #include "error.h"
14 #include "fd.h"
15 #include "list.h"
16 #include "osl_core.h"
17 /**
18 * A wrapper for lseek(2).
19 *
20 * \param fd The file descriptor whose offset is to be to repositioned.
21 * \param offset A value-result parameter.
22 * \param whence Usual repositioning directive.
23 *
24 * Reposition the offset of the file descriptor \a fd to the argument \a offset
25 * according to the directive \a whence. Upon successful return, \a offset
26 * contains the resulting offset location as measured in bytes from the
27 * beginning of the file.
28 *
29 * \return Positive on success. Otherwise, the function returns \p -E_LSEEK.
30 *
31 * \sa lseek(2).
32 */
33 int para_lseek(int fd, off_t *offset, int whence)
34 {
35 *offset = lseek(fd, *offset, whence);
36 int ret = -E_LSEEK;
37 if (*offset == -1)
38 return ret;
39 return 1;
40 }
41
42 /**
43 * Wrapper for the write system call.
44 *
45 * \param fd The file descriptor to write to.
46 * \param buf The buffer to write.
47 * \param size The length of \a buf in bytes.
48 *
49 * This function writes out the given buffer and retries if an interrupt
50 * occurred during the write.
51 *
52 * \return On success, the number of bytes written is returned, otherwise, the
53 * function returns \p -E_WRITE.
54 *
55 * \sa write(2).
56 */
57 ssize_t para_write(int fd, const void *buf, size_t size)
58 {
59 ssize_t ret;
60
61 for (;;) {
62 ret = write(fd, buf, size);
63 if ((ret < 0) && (errno == EAGAIN || errno == EINTR))
64 continue;
65 return ret >= 0? ret : -E_WRITE;
66 }
67 }
68
69 /**
70 * Write the whole buffer to a file descriptor.
71 *
72 * \param fd The file descriptor to write to.
73 * \param buf The buffer to write.
74 * \param size The length of \a buf in bytes.
75 *
76 * This function writes the given buffer and continues on short writes and
77 * when interrupted by a signal.
78 *
79 * \return Positive on success, negative on errors. Possible errors: any
80 * errors returned by para_write().
81 *
82 * \sa para_write().
83 */
84 ssize_t para_write_all(int fd, const void *buf, size_t size)
85 {
86 // DEBUG_LOG("writing %zu bytes\n", size);
87 const char *b = buf;
88 while (size) {
89 ssize_t ret = para_write(fd, b, size);
90 // DEBUG_LOG("ret: %zd\n", ret);
91 if (ret < 0)
92 return ret;
93 b += ret;
94 size -= ret;
95 }
96 return 1;
97 }
98 /**
99 * Open a file, write the given buffer and close the file.
100 *
101 * \param filename Full path to the file to open.
102 * \param buf The buffer to write to the file.
103 * \param size The size of \a buf.
104 *
105 * \return Positive on success, negative on errors. Possible errors include:
106 * any errors from para_open() or para_write().
107 *
108 * \sa para_open(), para_write().
109 */
110 int para_write_file(const char *filename, const void *buf, size_t size)
111 {
112 int ret, fd;
113
114 ret = para_open(filename, O_WRONLY | O_CREAT | O_EXCL, 0644);
115 if (ret < 0)
116 return ret;
117 fd = ret;
118 ret = para_write_all(fd, buf, size);
119 if (ret < 0)
120 goto out;
121 ret = 1;
122 out:
123 close(fd);
124 return ret;
125 }
126
127 static int append_file(const char *filename, char *header, size_t header_size,
128 char *data, size_t data_size, uint32_t *new_pos)
129 {
130 int ret, fd;
131
132 // DEBUG_LOG("appending %zu + %zu bytes\n", header_size, data_size);
133 ret = para_open(filename, O_WRONLY | O_CREAT | O_APPEND, 0644);
134 if (ret < 0)
135 return ret;
136 fd = ret;
137 if (header && header_size) {
138 ret = para_write_all(fd, header, header_size);
139 if (ret < 0)
140 goto out;
141 }
142 ret = para_write_all(fd, data, data_size);
143 if (ret < 0)
144 goto out;
145 if (new_pos) {
146 off_t offset = 0;
147 ret = para_lseek(fd, &offset, SEEK_END);
148 if (ret < 0)
149 goto out;
150 // DEBUG_LOG("new file size: " FMT_OFF_T "\n", offset);
151 *new_pos = offset;
152 }
153 ret = 1;
154 out:
155 close(fd);
156 return ret;
157 }
158
159 /**
160 * Traverse the given directory recursively.
161 *
162 * \param dirname The directory to traverse.
163 * \param func The function to call for each entry.
164 * \param private_data Pointer to an arbitrary data structure.
165 *
166 * For each regular file under \a dirname, the supplied function \a func is
167 * called. The full path of the regular file and the \a private_data pointer
168 * are passed to \a func. Directories for which the calling process has no
169 * permissions to change to are silently ignored.
170 *
171 * \return Standard.
172 */
173 int for_each_file_in_dir(const char *dirname,
174 int (*func)(const char *, void *), void *private_data)
175 {
176 DIR *dir;
177 struct dirent *entry;
178 int cwd_fd, ret2, ret = para_opendir(dirname, &dir, &cwd_fd);
179
180 if (ret < 0)
181 return ret == -ERRNO_TO_ERROR(EACCES)? 1 : ret;
182 /* scan cwd recursively */
183 while ((entry = readdir(dir))) {
184 mode_t m;
185 char *tmp;
186 struct stat s;
187
188 if (!strcmp(entry->d_name, "."))
189 continue;
190 if (!strcmp(entry->d_name, ".."))
191 continue;
192 if (lstat(entry->d_name, &s) == -1)
193 continue;
194 m = s.st_mode;
195 if (!S_ISREG(m) && !S_ISDIR(m))
196 continue;
197 tmp = make_message("%s/%s", dirname, entry->d_name);
198 if (!S_ISDIR(m)) {
199 ret = func(tmp, private_data);
200 free(tmp);
201 if (ret < 0)
202 goto out;
203 continue;
204 }
205 /* directory */
206 ret = for_each_file_in_dir(tmp, func, private_data);
207 free(tmp);
208 if (ret < 0)
209 goto out;
210 }
211 ret = 1;
212 out:
213 closedir(dir);
214 ret2 = para_fchdir(cwd_fd);
215 if (ret2 < 0 && ret >= 0)
216 ret = ret2;
217 close(cwd_fd);
218 return ret;
219 }
220
221 static int verify_name(const char *name)
222 {
223 if (!name)
224 return -E_BAD_NAME;
225 if (!*name)
226 return -E_BAD_NAME;
227 if (strchr(name, '/'))
228 return -E_BAD_NAME;
229 if (!strcmp(name, ".."))
230 return -E_BAD_NAME;
231 if (!strcmp(name, "."))
232 return -E_BAD_NAME;
233 return 1;
234 }
235
236 /**
237 * Compare two osl objects pointing to unsigned integers of 32 bit size.
238 *
239 * \param obj1 Pointer to the first integer.
240 * \param obj2 Pointer to the second integer.
241 *
242 * \return The values required for an osl compare function.
243 *
244 * \sa osl_compare_func, osl_hash_compare().
245 */
246 int uint32_compare(const struct osl_object *obj1, const struct osl_object *obj2)
247 {
248 uint32_t d1 = read_u32((const char *)obj1->data);
249 uint32_t d2 = read_u32((const char *)obj2->data);
250
251 if (d1 < d2)
252 return 1;
253 if (d1 > d2)
254 return -1;
255 return 0;
256 }
257
258 /**
259 * Compare two osl objects pointing to hash values.
260 *
261 * \param obj1 Pointer to the first hash object.
262 * \param obj2 Pointer to the second hash object.
263 *
264 * \return The values required for an osl compare function.
265 *
266 * \sa osl_compare_func, uint32_compare().
267 */
268 int osl_hash_compare(const struct osl_object *obj1, const struct osl_object *obj2)
269 {
270 return hash_compare((HASH_TYPE *)obj1->data, (HASH_TYPE *)obj2->data);
271 }
272
273 static char *disk_storage_dirname(const struct osl_table *t, unsigned col_num,
274 const char *ds_name)
275 {
276 char *dirname, *column_name = column_filename(t, col_num);
277
278 if (!(t->desc->flags & OSL_LARGE_TABLE))
279 return column_name;
280 dirname = make_message("%s/%.2s", column_name, ds_name);
281 free(column_name);
282 return dirname;
283 }
284
285 static char *disk_storage_name_of_object(const struct osl_table *t,
286 const struct osl_object *obj)
287 {
288 HASH_TYPE hash[HASH_SIZE];
289 hash_object(obj, hash);
290 return disk_storage_name_of_hash(t, hash);
291 }
292
293 static int disk_storage_name_of_row(const struct osl_table *t,
294 const struct osl_row *row, char **name)
295 {
296 struct osl_object obj;
297 int ret = osl_get_object(t, row, t->disk_storage_name_column, &obj);
298
299 if (ret < 0)
300 return ret;
301 *name = disk_storage_name_of_object(t, &obj);
302 return 1;
303 }
304
305 static void column_name_hash(const char *col_name, HASH_TYPE *hash)
306 {
307 hash_function(col_name, strlen(col_name), hash);
308 }
309
310 static int init_column_descriptions(struct osl_table *t)
311 {
312 int i, j, ret;
313 const struct osl_column_description *cd;
314
315 ret = -E_BAD_TABLE_DESC;
316 ret = verify_name(t->desc->name);
317 if (ret < 0)
318 goto err;
319 ret = -E_BAD_DB_DIR;
320 if (!t->desc->dir && (t->num_disk_storage_columns || t->num_mapped_columns))
321 goto err;
322 /* the size of the index header without column descriptions */
323 t->index_header_size = IDX_COLUMN_DESCRIPTIONS;
324 FOR_EACH_COLUMN(i, t->desc, cd) {
325 struct osl_column *col = t->columns + i;
326 if (cd->storage_flags & OSL_RBTREE) {
327 if (!cd->compare_function)
328 return -E_NO_COMPARE_FUNC;
329 }
330 if (cd->storage_type == OSL_NO_STORAGE)
331 continue;
332 ret = -E_NO_COLUMN_NAME;
333 if (!cd->name || !cd->name[0])
334 goto err;
335 ret = verify_name(cd->name);
336 if (ret < 0)
337 goto err;
338 t->index_header_size += index_column_description_size(cd->name);
339 column_name_hash(cd->name, col->name_hash);
340 ret = -E_DUPLICATE_COL_NAME;
341 for (j = i + 1; j < t->desc->num_columns; j++) {
342 const char *name2 = get_column_description(t->desc,
343 j)->name;
344 if (cd->name && name2 && !strcmp(cd->name, name2))
345 goto err;
346 }
347 }
348 return 1;
349 err:
350 return ret;
351 }
352
353 /**
354 * Initialize a struct table from given table description.
355 *
356 * \param desc The description of the osl table.
357 * \param table_ptr Result is returned here.
358 *
359 * This function performs several sanity checks on \p desc and returns if any
360 * of these tests fail. On success, a struct \p osl_table is allocated and
361 * initialized with data derived from \p desc.
362 *
363 * \return Positive on success, negative on errors. Possible errors include: \p
364 * E_BAD_TABLE_DESC, \p E_NO_COLUMN_DESC, \p E_NO_COLUMNS, \p
365 * E_BAD_STORAGE_TYPE, \p E_BAD_STORAGE_FLAGS, \p E_BAD_STORAGE_SIZE, \p
366 * E_NO_UNIQUE_RBTREE_COLUMN, \p E_NO_RBTREE_COL.
367 *
368 * \sa struct osl_table.
369 */
370 int init_table_structure(const struct osl_table_description *desc,
371 struct osl_table **table_ptr)
372 {
373 const struct osl_column_description *cd;
374 struct osl_table *t = para_calloc(sizeof(*t));
375 int i, ret = -E_BAD_TABLE_DESC, have_disk_storage_name_column = 0;
376
377 if (!desc)
378 goto err;
379 DEBUG_LOG("creating table structure for '%s' from table "
380 "description\n", desc->name);
381 ret = -E_NO_COLUMN_DESC;
382 if (!desc->column_descriptions)
383 goto err;
384 ret = -E_NO_COLUMNS;
385 if (!desc->num_columns)
386 goto err;
387 t->columns = para_calloc(desc->num_columns * sizeof(struct osl_column));
388 t->desc = desc;
389 FOR_EACH_COLUMN(i, t->desc, cd) {
390 enum osl_storage_type st = cd->storage_type;
391 enum osl_storage_flags sf = cd->storage_flags;
392 struct osl_column *col = &t->columns[i];
393
394 ret = -E_BAD_STORAGE_TYPE;
395 if (st != OSL_MAPPED_STORAGE && st != OSL_DISK_STORAGE
396 && st != OSL_NO_STORAGE)
397 goto err;
398 ret = -E_BAD_STORAGE_FLAGS;
399 if (st == OSL_DISK_STORAGE && sf & OSL_RBTREE)
400 goto err;
401 ret = -E_BAD_STORAGE_SIZE;
402 if (sf & OSL_FIXED_SIZE && !cd->data_size)
403 goto err;
404 switch (st) {
405 case OSL_DISK_STORAGE:
406 t->num_disk_storage_columns++;
407 break;
408 case OSL_MAPPED_STORAGE:
409 t->num_mapped_columns++;
410 col->index_offset = t->row_index_size;
411 t->row_index_size += 8;
412 break;
413 case OSL_NO_STORAGE:
414 col->volatile_num = t->num_volatile_columns;
415 t->num_volatile_columns++;
416 break;
417 }
418 if (sf & OSL_RBTREE) {
419 col->rbtree_num = t->num_rbtrees;
420 t->num_rbtrees++;
421 if ((sf & OSL_UNIQUE) && (st == OSL_MAPPED_STORAGE)) {
422 if (!have_disk_storage_name_column)
423 t->disk_storage_name_column = i;
424 have_disk_storage_name_column = 1;
425 }
426 }
427 }
428 ret = -E_NO_UNIQUE_RBTREE_COLUMN;
429 if (t->num_disk_storage_columns && !have_disk_storage_name_column)
430 goto err;
431 ret = -E_NO_RBTREE_COL;
432 if (!t->num_rbtrees)
433 goto err;
434 /* success */
435 DEBUG_LOG("OK. Index entry size: %u\n", t->row_index_size);
436 ret = init_column_descriptions(t);
437 if (ret < 0)
438 goto err;
439 *table_ptr = t;
440 return 1;
441 err:
442 free(t->columns);
443 free(t);
444 return ret;
445 }
446
447 /**
448 * Read the table description from index header.
449 *
450 * \param map The memory mapping of the index file.
451 * \param desc The values found in the index header are returned here.
452 *
453 * Read the index header, check for the paraslash magic string and the table version number.
454 * Read all information stored in the index header into \a desc.
455 *
456 * \return Positive on success, negative on errors.
457 *
458 * \sa struct osl_table_description, osl_create_table.
459 */
460 int read_table_desc(struct osl_object *map, struct osl_table_description *desc)
461 {
462 char *buf = map->data;
463 uint8_t version;
464 uint16_t header_size;
465 int ret, i;
466 unsigned offset;
467 struct osl_column_description *cd;
468
469 if (map->size < MIN_INDEX_HEADER_SIZE(1))
470 return -E_SHORT_TABLE;
471 if (strncmp(buf + IDX_PARA_MAGIC, PARA_MAGIC, strlen(PARA_MAGIC)))
472 return -E_NO_MAGIC;
473 version = read_u8(buf + IDX_VERSION);
474 if (version < MIN_TABLE_VERSION || version > MAX_TABLE_VERSION)
475 return -E_VERSION_MISMATCH;
476 desc->flags = read_u8(buf + IDX_TABLE_FLAGS);
477 desc->num_columns = read_u16(buf + IDX_NUM_COLUMNS);
478 DEBUG_LOG("%u columns\n", desc->num_columns);
479 if (!desc->num_columns)
480 return -E_NO_COLUMNS;
481 header_size = read_u16(buf + IDX_HEADER_SIZE);
482 if (map->size < header_size)
483 return -E_BAD_SIZE;
484 desc->column_descriptions = para_calloc(desc->num_columns
485 * sizeof(struct osl_column_description));
486 offset = IDX_COLUMN_DESCRIPTIONS;
487 FOR_EACH_COLUMN(i, desc, cd) {
488 char *null_byte;
489
490 ret = -E_SHORT_TABLE;
491 if (map->size < offset + MIN_IDX_COLUMN_DESCRIPTION_SIZE) {
492 ERROR_LOG("map size = %zu < %u = offset + min desc size\n",
493 map->size, offset + MIN_IDX_COLUMN_DESCRIPTION_SIZE);
494 goto err;
495 }
496 cd->storage_type = read_u16(buf + offset + IDX_CD_STORAGE_TYPE);
497 cd->storage_flags = read_u16(buf + offset +
498 IDX_CD_STORAGE_FLAGS);
499 cd->data_size = read_u32(buf + offset + IDX_CD_DATA_SIZE);
500 null_byte = memchr(buf + offset + IDX_CD_NAME, '\0',
501 map->size - offset - IDX_CD_NAME);
502 ret = -E_INDEX_CORRUPTION;
503 if (!null_byte)
504 goto err;
505 cd->name = para_strdup(buf + offset + IDX_CD_NAME);
506 offset += index_column_description_size(cd->name);
507 }
508 if (offset != header_size) {
509 ret = -E_INDEX_CORRUPTION;
510 ERROR_LOG("real header size = %u != %u = stored header size\n",
511 offset, header_size);
512 goto err;
513 }
514 return 1;
515 err:
516 FOR_EACH_COLUMN(i, desc, cd)
517 free(cd->name);
518 return ret;
519 }
520
521 /*
522 * check whether the table description given by \p t->desc matches the on-disk
523 * table structure stored in the index of \a t.
524 */
525 static int compare_table_descriptions(struct osl_table *t)
526 {
527 int i, ret;
528 struct osl_table_description desc;
529 const struct osl_column_description *cd1, *cd2;
530
531 /* read the on-disk structure into desc */
532 ret = read_table_desc(&t->index_map, &desc);
533 if (ret < 0)
534 return ret;
535 ret = -E_BAD_TABLE_FLAGS;
536 if (desc.flags != t->desc->flags)
537 goto out;
538 ret = -E_BAD_COLUMN_NUM;
539 if (desc.num_columns > t->desc->num_columns)
540 goto out;
541 if (desc.num_columns < t->desc->num_columns) {
542 struct osl_column_description *cd;
543 unsigned diff = t->desc->num_columns - desc.num_columns;
544 INFO_LOG("extending table by %u volatile columns\n", diff);
545 desc.column_descriptions = para_realloc(desc.column_descriptions,
546 t->desc->num_columns * sizeof(struct osl_column_description));
547 for (i = desc.num_columns; i < t->desc->num_columns; i++) {
548 cd = get_column_description(&desc, i);
549 cd->storage_type = OSL_NO_STORAGE;
550 cd->name = NULL;
551 }
552 desc.num_columns += diff;
553 }
554 FOR_EACH_COLUMN(i, t->desc, cd1) {
555 cd2 = get_column_description(&desc, i);
556 ret = -E_BAD_STORAGE_TYPE;
557 if (cd1->storage_type != cd2->storage_type)
558 goto out;
559 if (cd1->storage_type == OSL_NO_STORAGE)
560 continue;
561 ret = -E_BAD_STORAGE_FLAGS;
562 if (cd1->storage_flags != cd2->storage_flags) {
563 ERROR_LOG("sf1 = %u != %u = sf2\n",
564 cd1->storage_flags, cd2->storage_flags);
565 goto out;
566 }
567 ret = -E_BAD_DATA_SIZE;
568 if (cd1->storage_flags & OSL_FIXED_SIZE)
569 if (cd1->data_size != cd2->data_size)
570 goto out;
571 ret = -E_BAD_COLUMN_NAME;
572 if (strcmp(cd1->name, cd2->name))
573 goto out;
574 }
575 DEBUG_LOG("table description of '%s' matches on-disk data, good\n",
576 t->desc->name);
577 ret = 1;
578 out:
579 FOR_EACH_COLUMN(i, &desc, cd1)
580 free(cd1->name);
581 free(desc.column_descriptions);
582 return ret;
583 }
584
585 static int create_table_index(struct osl_table *t)
586 {
587 char *buf, *filename;
588 int i, ret;
589 size_t size = t->index_header_size;
590 const struct osl_column_description *cd;
591 unsigned offset;
592
593 INFO_LOG("creating %zu byte index for table %s\n", size,
594 t->desc->name);
595 buf = para_calloc(size);
596 sprintf(buf + IDX_PARA_MAGIC, "%s", PARA_MAGIC);
597 write_u8(buf + IDX_TABLE_FLAGS, t->desc->flags);
598 write_u8(buf + IDX_DIRTY_FLAG, 0);
599 write_u8(buf + IDX_VERSION, CURRENT_TABLE_VERSION);
600 write_u16(buf + IDX_NUM_COLUMNS, t->num_mapped_columns + t->num_disk_storage_columns);
601 write_u16(buf + IDX_HEADER_SIZE, t->index_header_size);
602 offset = IDX_COLUMN_DESCRIPTIONS;
603 FOR_EACH_COLUMN(i, t->desc, cd) {
604 /* no need to store info about volatile storage */
605 if (cd->storage_type == OSL_NO_STORAGE)
606 continue;
607 write_u16(buf + offset + IDX_CD_STORAGE_TYPE,
608 cd->storage_type);
609 write_u16(buf + offset + IDX_CD_STORAGE_FLAGS,
610 cd->storage_flags);
611 if (cd->storage_flags & OSL_FIXED_SIZE)
612 write_u32(buf + offset + IDX_CD_DATA_SIZE,
613 cd->data_size);
614 strcpy(buf + offset + IDX_CD_NAME, cd->name);
615 offset += index_column_description_size(cd->name);
616 }
617 assert(offset = size);
618 filename = index_filename(t->desc);
619 ret = para_write_file(filename, buf, size);
620 free(buf);
621 free(filename);
622 return ret;
623 }
624
625 /**
626 * Create a new osl table.
627 *
628 * \param desc Pointer to the table description.
629 *
630 * \return Standard.
631 */
632 int osl_create_table(const struct osl_table_description *desc)
633 {
634 const struct osl_column_description *cd;
635 char *table_dir = NULL, *filename;
636 struct osl_table *t;
637 int i, ret = init_table_structure(desc, &t);
638
639 if (ret < 0)
640 return ret;
641 INFO_LOG("creating %s\n", desc->name);
642 FOR_EACH_COLUMN(i, t->desc, cd) {
643 if (cd->storage_type == OSL_NO_STORAGE)
644 continue;
645 if (!table_dir) {
646 ret = para_mkdir(desc->dir, 0777);
647 if (ret < 0 && !is_errno(-ret, EEXIST))
648 goto out;
649 table_dir = make_message("%s/%s", desc->dir,
650 desc->name);
651 ret = para_mkdir(table_dir, 0777);
652 if (ret < 0)
653 goto out;
654 }
655 filename = column_filename(t, i);
656 INFO_LOG("filename: %s\n", filename);
657 if (cd->storage_type == OSL_MAPPED_STORAGE) {
658 ret = para_open(filename, O_RDWR | O_CREAT | O_EXCL,
659 0644);
660 free(filename);
661 if (ret < 0)
662 goto out;
663 close(ret);
664 continue;
665 }
666 /* DISK STORAGE */
667 ret = para_mkdir(filename, 0777);
668 free(filename);
669 if (ret < 0)
670 goto out;
671 }
672 if (t->num_mapped_columns) {
673 ret = create_table_index(t);
674 if (ret < 0)
675 goto out;
676 }
677 ret = 1;
678 out:
679 free(table_dir);
680 free(t->columns);
681 free(t);
682 return ret;
683 }
684
685 static int table_is_dirty(struct osl_table *t)
686 {
687 char *buf = (char *)t->index_map.data + IDX_DIRTY_FLAG;
688 uint8_t dirty = read_u8(buf) & 0x1;
689 return !!dirty;
690 }
691
692 static void mark_table_dirty(struct osl_table *t)
693 {
694 char *buf = (char *)t->index_map.data + IDX_DIRTY_FLAG;
695 write_u8(buf, read_u8(buf) | 1);
696 }
697
698 static void mark_table_clean(struct osl_table *t)
699 {
700 char *buf = (char *)t->index_map.data + IDX_DIRTY_FLAG;
701 write_u8(buf, read_u8(buf) & 0xfe);
702 }
703
704 static void unmap_column(struct osl_table *t, unsigned col_num)
705 {
706 struct osl_object map = t->columns[col_num].data_map;
707 int ret;
708 if (!map.data)
709 return;
710 ret = para_munmap(map.data, map.size);
711 assert(ret > 0);
712 map.data = NULL;
713 }
714
715 /**
716 * Unmap all mapped files of an osl table.
717 *
718 * \param t Pointer to a mapped table.
719 * \param flags Options for unmapping.
720 *
721 * \return Positive on success, negative on errors.
722 *
723 * \sa map_table(), enum osl_close_flags, para_munmap().
724 */
725 int unmap_table(struct osl_table *t, enum osl_close_flags flags)
726 {
727 unsigned i;
728 const struct osl_column_description *cd;
729 int ret;
730
731 if (!t->num_mapped_columns) /* can this ever happen? */
732 return 1;
733 DEBUG_LOG("unmapping table '%s'\n", t->desc->name);
734 if (!t->index_map.data)
735 return -E_NOT_MAPPED;
736 if (flags & OSL_MARK_CLEAN)
737 mark_table_clean(t);
738 ret = para_munmap(t->index_map.data, t->index_map.size);
739 if (ret < 0)
740 return ret;
741 t->index_map.data = NULL;
742 if (!t->num_rows)
743 return 1;
744 FOR_EACH_MAPPED_COLUMN(i, t, cd)
745 unmap_column(t, i);
746 return 1;
747 }
748
749 static int map_column(struct osl_table *t, unsigned col_num)
750 {
751 struct stat statbuf;
752 char *filename = column_filename(t, col_num);
753 int ret = -E_STAT;
754 if (stat(filename, &statbuf) < 0) {
755 free(filename);
756 return ret;
757 }
758 if (!(S_IFREG & statbuf.st_mode)) {
759 free(filename);
760 return ret;
761 }
762 ret = mmap_full_file(filename, O_RDWR,
763 &t->columns[col_num].data_map.data,
764 &t->columns[col_num].data_map.size,
765 NULL);
766 free(filename);
767 return ret;
768 }
769
770 /**
771 * Map the index file and all columns of type \p OSL_MAPPED_STORAGE into memory.
772 *
773 * \param t Pointer to an initialized table structure.
774 * \param flags Mapping options.
775 *
776 * \return Negative return value on errors; on success the number of rows
777 * (including invalid rows) is returned.
778 *
779 * \sa unmap_table(), enum map_table_flags, osl_open_table(), mmap(2).
780 */
781 int map_table(struct osl_table *t, enum map_table_flags flags)
782 {
783 char *filename;
784 const struct osl_column_description *cd;
785 int i = 0, ret, num_rows = 0;
786
787 if (!t->num_mapped_columns)
788 return 0;
789 if (t->index_map.data)
790 return -E_ALREADY_MAPPED;
791 filename = index_filename(t->desc);
792 DEBUG_LOG("mapping table '%s' (index: %s)\n", t->desc->name, filename);
793 ret = mmap_full_file(filename, flags & MAP_TBL_FL_MAP_RDONLY?
794 O_RDONLY : O_RDWR, &t->index_map.data, &t->index_map.size, NULL);
795 free(filename);
796 if (ret < 0)
797 return ret;
798 if (flags & MAP_TBL_FL_VERIFY_INDEX) {
799 ret = compare_table_descriptions(t);
800 if (ret < 0)
801 goto err;
802 }
803 ret = -E_BUSY;
804 if (!(flags & MAP_TBL_FL_IGNORE_DIRTY)) {
805 if (table_is_dirty(t)) {
806 ERROR_LOG("%s is dirty\n", t->desc->name);
807 goto err;
808 }
809 }
810 mark_table_dirty(t);
811 num_rows = table_num_rows(t);
812 if (!num_rows)
813 return num_rows;
814 /* map data files */
815 FOR_EACH_MAPPED_COLUMN(i, t, cd) {
816 ret = map_column(t, i);
817 if (ret < 0)
818 goto err;
819 }
820 return num_rows;
821 err: /* unmap what is already mapped */
822 for (i--; i >= 0; i--) {
823 struct osl_object map = t->columns[i].data_map;
824 para_munmap(map.data, map.size);
825 map.data = NULL;
826 }
827 para_munmap(t->index_map.data, t->index_map.size);
828 t->index_map.data = NULL;
829 return ret;
830 }
831
832 /**
833 * Retrieve a mapped object by row and column number.
834 *
835 * \param t Pointer to an open osl table.
836 * \param col_num Number of the mapped column containing the object to retrieve.
837 * \param row_num Number of the row containing the object to retrieve.
838 * \param obj The result is returned here.
839 *
840 * It is considered an error if \a col_num does not refer to a column
841 * of storage type \p OSL_MAPPED_STORAGE.
842 *
843 * \return Positive on success, negative on errors. Possible errors include:
844 * \p E_BAD_ROW_NUM, \p E_INVALID_OBJECT.
845 *
846 * \sa osl_storage_type.
847 */
848 int get_mapped_object(const struct osl_table *t, unsigned col_num,
849 uint32_t row_num, struct osl_object *obj)
850 {
851 struct osl_column *col = &t->columns[col_num];
852 uint32_t offset;
853 char *header;
854 char *cell_index;
855 int ret;
856
857 if (t->num_rows <= row_num)
858 return -E_BAD_ROW_NUM;
859 ret = get_cell_index(t, row_num, col_num, &cell_index);
860 if (ret < 0)
861 return ret;
862 offset = read_u32(cell_index);
863 obj->size = read_u32(cell_index + 4) - 1;
864 header = col->data_map.data + offset;
865 obj->data = header + 1;
866 if (read_u8(header) == 0xff) {
867 ERROR_LOG("col %u, size %zu, offset %u\n", col_num,
868 obj->size, offset);
869 return -E_INVALID_OBJECT;
870 }
871 return 1;
872 }
873
874 static int search_rbtree(const struct osl_object *obj,
875 const struct osl_table *t, unsigned col_num,
876 struct rb_node **result, struct rb_node ***rb_link)
877 {
878 struct osl_column *col = &t->columns[col_num];
879 struct rb_node **new = &col->rbtree.rb_node, *parent = NULL;
880 const struct osl_column_description *cd =
881 get_column_description(t->desc, col_num);
882 enum osl_storage_type st = cd->storage_type;
883 while (*new) {
884 struct osl_row *this_row = get_row_pointer(*new,
885 col->rbtree_num);
886 int ret;
887 struct osl_object this_obj;
888 parent = *new;
889 if (st == OSL_MAPPED_STORAGE) {
890 ret = get_mapped_object(t, col_num, this_row->num,
891 &this_obj);
892 if (ret < 0)
893 return ret;
894 } else
895 this_obj = this_row->volatile_objects[col->volatile_num];
896 ret = cd->compare_function(obj, &this_obj);
897 if (!ret) {
898 if (result)
899 *result = get_rb_node_pointer(this_row,
900 col->rbtree_num);
901 return 1;
902 }
903 if (ret < 0)
904 new = &((*new)->rb_left);
905 else
906 new = &((*new)->rb_right);
907 }
908 if (result)
909 *result = parent;
910 if (rb_link)
911 *rb_link = new;
912 return -E_RB_KEY_NOT_FOUND;
913 }
914
915 static int insert_rbtree(struct osl_table *t, unsigned col_num,
916 const struct osl_row *row, const struct osl_object *obj)
917 {
918 struct rb_node *parent, **rb_link;
919 unsigned rbtree_num;
920 struct rb_node *n;
921 int ret = search_rbtree(obj, t, col_num, &parent, &rb_link);
922
923 if (ret > 0)
924 return -E_RB_KEY_EXISTS;
925 rbtree_num = t->columns[col_num].rbtree_num;
926 n = get_rb_node_pointer(row, rbtree_num);
927 rb_link_node(n, parent, rb_link);
928 rb_insert_color(n, &t->columns[col_num].rbtree);
929 return 1;
930 }
931
932 static void remove_rb_node(struct osl_table *t, unsigned col_num,
933 const struct osl_row *row)
934 {
935 struct osl_column *col = &t->columns[col_num];
936 const struct osl_column_description *cd =
937 get_column_description(t->desc, col_num);
938 enum osl_storage_flags sf = cd->storage_flags;
939 struct rb_node *victim, *splice_out_node, *tmp;
940 if (!(sf & OSL_RBTREE))
941 return;
942 /*
943 * Which node is removed/spliced out actually depends on how many
944 * children the victim node has: If it has no children, it gets
945 * deleted. If it has one child, it gets spliced out. If it has two
946 * children, its successor (which has at most a right child) gets
947 * spliced out.
948 */
949 victim = get_rb_node_pointer(row, col->rbtree_num);
950 if (victim->rb_left && victim->rb_right)
951 splice_out_node = rb_next(victim);
952 else
953 splice_out_node = victim;
954 /* Go up to the root and decrement the size of each node in the path. */
955 for (tmp = splice_out_node; tmp; tmp = rb_parent(tmp))
956 tmp->size--;
957 rb_erase(victim, &col->rbtree);
958 }
959
960 static int add_row_to_rbtrees(struct osl_table *t, uint32_t row_num,
961 struct osl_object *volatile_objs, struct osl_row **row_ptr)
962 {
963 unsigned i;
964 int ret;
965 struct osl_row *row = allocate_row(t->num_rbtrees);
966 const struct osl_column_description *cd;
967
968 row->num = row_num;
969 row->volatile_objects = volatile_objs;
970 FOR_EACH_RBTREE_COLUMN(i, t, cd) {
971 if (cd->storage_type == OSL_MAPPED_STORAGE) {
972 struct osl_object obj;
973 ret = get_mapped_object(t, i, row_num, &obj);
974 if (ret < 0)
975 goto err;
976 ret = insert_rbtree(t, i, row, &obj);
977 } else { /* volatile */
978 const struct osl_object *obj
979 = volatile_objs + t->columns[i].volatile_num;
980 ret = insert_rbtree(t, i, row, obj);
981 }
982 if (ret < 0)
983 goto err;
984 }
985 if (row_ptr)
986 *row_ptr = row;
987 return 1;
988 err: /* rollback changes, i.e. remove added entries from rbtrees */
989 while (i)
990 remove_rb_node(t, i--, row);
991 free(row);
992 return ret;
993 }
994
995 static void free_volatile_objects(const struct osl_table *t,
996 enum osl_close_flags flags)
997 {
998 int i, j;
999 struct rb_node *n;
1000 struct osl_column *rb_col;
1001 const struct osl_column_description *cd;
1002
1003 if (!t->num_volatile_columns)
1004 return;
1005 /* find the first rbtree column (any will do) */
1006 FOR_EACH_RBTREE_COLUMN(i, t, cd)
1007 break;
1008 rb_col = t->columns + i;
1009 /* walk that rbtree and free all volatile objects */
1010 for (n = rb_first(&rb_col->rbtree); n; n = rb_next(n)) {
1011 struct osl_row *r = get_row_pointer(n, rb_col->rbtree_num);
1012 if (flags & OSL_FREE_VOLATILE)
1013 FOR_EACH_VOLATILE_COLUMN(j, t, cd) {
1014 if (cd->storage_flags & OSL_DONT_FREE)
1015 continue;
1016 free(r->volatile_objects[
1017 t->columns[j].volatile_num].data);
1018 }
1019 // for (j = 0; j < t->num_volatile_columns; j++)
1020 // free(r->volatile_objects[j].data);
1021 free(r->volatile_objects);
1022 }
1023 }
1024
1025 /**
1026 * Erase all rbtree nodes and free resources.
1027 *
1028 * \param t Pointer to an open osl table.
1029 *
1030 * This function is called by osl_close_table().
1031 */
1032 void clear_rbtrees(struct osl_table *t)
1033 {
1034 const struct osl_column_description *cd;
1035 unsigned i, rbtrees_cleared = 0;
1036
1037 FOR_EACH_RBTREE_COLUMN(i, t, cd) {
1038 struct osl_column *col = &t->columns[i];
1039 struct rb_node *n;
1040 rbtrees_cleared++;
1041 for (n = rb_first(&col->rbtree); n;) {
1042 struct osl_row *r;
1043 rb_erase(n, &col->rbtree);
1044 if (rbtrees_cleared == t->num_rbtrees) {
1045 r = get_row_pointer(n, col->rbtree_num);
1046 n = rb_next(n);
1047 free(r);
1048 } else
1049 n = rb_next(n);
1050 }
1051 }
1052
1053 }
1054
1055 /**
1056 * Close an osl table.
1057 *
1058 * \param t Pointer to the table to be closed.
1059 * \param flags Options for what should be cleaned up.
1060 *
1061 * If osl_open_table() succeeds, the resulting table pointer must later be
1062 * passed to this function in order to flush all changes to the file system and
1063 * to free the resources that were allocated by osl_open_table().
1064 *
1065 * \return Positive on success, negative on errors. Possible errors: \p E_BAD_TABLE,
1066 * errors returned by unmap_table().
1067 *
1068 * \sa osl_open_table(), unmap_table().
1069 */
1070 int osl_close_table(struct osl_table *t, enum osl_close_flags flags)
1071 {
1072 int ret;
1073
1074 if (!t)
1075 return -E_BAD_TABLE;
1076 free_volatile_objects(t, flags);
1077 clear_rbtrees(t);
1078 ret = unmap_table(t, flags);
1079 if (ret < 0)
1080 ERROR_LOG("unmap_table failed: %d\n", ret);
1081 free(t->columns);
1082 free(t);
1083 return ret;
1084 }
1085
1086 /**
1087 * Find out whether the given row number corresponds to an invalid row.
1088 *
1089 * \param t Pointer to the osl table.
1090 * \param row_num The number of the row in question.
1091 *
1092 * By definition, a row is considered invalid if all its index entries
1093 * are invalid.
1094 *
1095 * \return Positive if \a row_num corresponds to an invalid row,
1096 * zero if it corresponds to a valid row, negative on errors.
1097 */
1098 int row_is_invalid(struct osl_table *t, uint32_t row_num)
1099 {
1100 char *row_index;
1101 int i, ret = get_row_index(t, row_num, &row_index);
1102
1103 if (ret < 0)
1104 return ret;
1105 for (i = 0; i < t->row_index_size; i++) {
1106 if ((unsigned char)row_index[i] != 0xff)
1107 return 0;
1108 }
1109 INFO_LOG("row %d is invalid\n", row_num);
1110 return 1;
1111 }
1112
1113 /**
1114 * Invalidate a row of an osl table.
1115 *
1116 * \param t Pointer to an open osl table.
1117 * \param row_num Number of the row to mark as invalid.
1118 *
1119 * This function marks each mapped object in the index entry of \a row as
1120 * invalid.
1121 *
1122 * \return Positive on success, negative on errors.
1123 */
1124 int mark_row_invalid(struct osl_table *t, uint32_t row_num)
1125 {
1126 char *row_index;
1127 int ret = get_row_index(t, row_num, &row_index);
1128
1129 if (ret < 0)
1130 return ret;
1131 INFO_LOG("marking row %d as invalid\n", row_num);
1132 memset(row_index, 0xff, t->row_index_size);
1133 return 1;
1134 }
1135
1136 /**
1137 * Initialize all rbtrees and compute number of invalid rows.
1138 *
1139 * \param t The table containing the rbtrees to be initialized.
1140 *
1141 * \return Positive on success, negative on errors.
1142 */
1143 int init_rbtrees(struct osl_table *t)
1144 {
1145 int i, ret;
1146 const struct osl_column_description *cd;
1147
1148 /* create rbtrees */
1149 FOR_EACH_RBTREE_COLUMN(i, t, cd)
1150 t->columns[i].rbtree = RB_ROOT;
1151 /* add valid rows to rbtrees */
1152 t->num_invalid_rows = 0;
1153 for (i = 0; i < t->num_rows; i++) {
1154 ret = row_is_invalid(t, i);
1155 if (ret < 0)
1156 return ret;
1157 if (ret) {
1158 t->num_invalid_rows++;
1159 continue;
1160 }
1161 ret = add_row_to_rbtrees(t, i, NULL, NULL);
1162 if (ret < 0)
1163 return ret;
1164 }
1165 return 1;
1166 }
1167
1168 /**
1169 * Open an osl table.
1170 *
1171 * Each osl table must be opened before its data can be accessed.
1172 *
1173 * \param table_desc Describes the table to be opened.
1174 * \param result Contains a pointer to the open table on success.
1175 *
1176 * The table description given by \a desc should coincide with the
1177 * description used at creation time.
1178 *
1179 * \return Standard.
1180 */
1181 int osl_open_table(const struct osl_table_description *table_desc,
1182 struct osl_table **result)
1183 {
1184 int i, ret;
1185 struct osl_table *t;
1186 const struct osl_column_description *cd;
1187
1188 INFO_LOG("opening table %s\n", table_desc->name);
1189 ret = init_table_structure(table_desc, &t);
1190 if (ret < 0)
1191 return ret;
1192 FOR_EACH_DISK_STORAGE_COLUMN(i, t, cd) {
1193 /* check if directory exists */
1194 char *dirname = column_filename(t, i);
1195 struct stat statbuf;
1196 ret = stat(dirname, &statbuf);
1197 free(dirname);
1198 if (ret < 0) {
1199 ret = -ERRNO_TO_ERROR(errno);
1200 goto err;
1201 }
1202 ret = -ERRNO_TO_ERROR(ENOTDIR);
1203 if (!S_ISDIR(statbuf.st_mode))
1204 goto err;
1205 }
1206 ret = map_table(t, MAP_TBL_FL_VERIFY_INDEX);
1207 if (ret < 0)
1208 goto err;
1209 t->num_rows = ret;
1210 DEBUG_LOG("num rows: %d\n", t->num_rows);
1211 ret = init_rbtrees(t);
1212 if (ret < 0) {
1213 osl_close_table(t, OSL_MARK_CLEAN); /* ignore further errors */
1214 return ret;
1215 }
1216 *result = t;
1217 return 1;
1218 err:
1219 free(t->columns);
1220 free(t);
1221 return ret;
1222 }
1223
1224 static int create_disk_storage_object_dir(const struct osl_table *t,
1225 unsigned col_num, const char *ds_name)
1226 {
1227 char *dirname;
1228 int ret;
1229
1230 if (!(t->desc->flags & OSL_LARGE_TABLE))
1231 return 1;
1232 dirname = disk_storage_dirname(t, col_num, ds_name);
1233 ret = para_mkdir(dirname, 0777);
1234 free(dirname);
1235 if (ret < 0 && !is_errno(-ret, EEXIST))
1236 return ret;
1237 return 1;
1238 }
1239
1240 static int write_disk_storage_file(const struct osl_table *t, unsigned col_num,
1241 const struct osl_object *obj, const char *ds_name)
1242 {
1243 int ret;
1244 char *filename;
1245
1246 ret = create_disk_storage_object_dir(t, col_num, ds_name);
1247 if (ret < 0)
1248 return ret;
1249 filename = disk_storage_path(t, col_num, ds_name);
1250 ret = para_write_file(filename, obj->data, obj->size);
1251 free(filename);
1252 return ret;
1253 }
1254
1255 static int append_map_file(const struct osl_table *t, unsigned col_num,
1256 const struct osl_object *obj, uint32_t *new_size)
1257 {
1258 char *filename = column_filename(t, col_num);
1259 int ret;
1260 char header = 0; /* zero means valid object */
1261
1262 // DEBUG_LOG("appending %zu + 1 byte\n", obj->size);
1263 ret = append_file(filename, &header, 1, obj->data, obj->size,
1264 new_size);
1265 free(filename);
1266 return ret;
1267 }
1268
1269 static int append_row_index(const struct osl_table *t, char *row_index)
1270 {
1271 char *filename;
1272 int ret;
1273
1274 if (!t->num_mapped_columns)
1275 return 1;
1276 filename = index_filename(t->desc);
1277 ret = append_file(filename, NULL, 0, row_index,
1278 t->row_index_size, NULL);
1279 free(filename);
1280 return ret;
1281 }
1282
1283 /**
1284 * A wrapper for truncate(2)
1285 *
1286 * \param path Name of the regular file to truncate
1287 * \param size Number of bytes to \b shave \b off
1288 *
1289 * Truncate the regular file named by \a path by \a size bytes.
1290 *
1291 * \return Positive on success, negative on errors. Possible errors include: \p
1292 * E_STAT, \p E_BAD_SIZE, \p E_TRUNC.
1293 *
1294 * \sa truncate(2)
1295 */
1296 int para_truncate(const char *path, off_t size)
1297 {
1298 int ret;
1299 struct stat statbuf;
1300
1301 ret = -E_STAT;
1302 if (stat(path, &statbuf) < 0)
1303 goto out;
1304 ret = -E_BAD_SIZE;
1305 if (statbuf.st_size < size)
1306 goto out;
1307 ret = -E_TRUNC;
1308 if (truncate(path, statbuf.st_size - size) < 0)
1309 goto out;
1310 ret = 1;
1311 out:
1312 return ret;
1313 }
1314
1315 static int truncate_mapped_file(const struct osl_table *t, unsigned col_num,
1316 off_t size)
1317 {
1318 char *filename = column_filename(t, col_num);
1319 int ret = para_truncate(filename, size);
1320 free(filename);
1321 return ret;
1322 }
1323
1324 static int delete_disk_storage_file(const struct osl_table *t, unsigned col_num,
1325 const char *ds_name)
1326 {
1327 char *dirname, *filename = disk_storage_path(t, col_num, ds_name);
1328 int ret = unlink(filename), err = errno;
1329
1330 free(filename);
1331 if (ret < 0)
1332 return -ERRNO_TO_ERROR(err);
1333 if (!(t->desc->flags & OSL_LARGE_TABLE))
1334 return 1;
1335 dirname = disk_storage_dirname(t, col_num, ds_name);
1336 rmdir(dirname);
1337 free(dirname);
1338 return 1;
1339 }
1340
1341 /**
1342 * Add a new row to an osl table and retrieve this row.
1343 *
1344 * \param t Pointer to an open osl table.
1345 * \param objects Array of objects to be added.
1346 * \param row Result pointer.
1347 *
1348 * The \a objects parameter must point to an array containing one object per
1349 * column. The order of the objects in the array is given by the table
1350 * description of \a table. Several sanity checks are performed during object
1351 * insertion and the function returns without modifying the table if any of
1352 * these tests fail. In fact, it is atomic in the sense that it either
1353 * succeeds or leaves the table unchanged (i.e. either all or none of the
1354 * objects are added to the table).
1355 *
1356 * It is considered an error if an object is added to a column with associated
1357 * rbtree if this object is equal to an object already contained in that column
1358 * (i.e. the compare function for the column's rbtree returns zero).
1359 *
1360 * Possible errors include: \p E_RB_KEY_EXISTS, \p E_BAD_DATA_SIZE.
1361 *
1362 * \return Positive on success, negative on errors.
1363 *
1364 * \sa struct osl_table_description, osl_compare_func, osl_add_row().
1365 */
1366 int osl_add_and_get_row(struct osl_table *t, struct osl_object *objects,
1367 struct osl_row **row)
1368 {
1369 int i, ret;
1370 char *ds_name = NULL;
1371 struct rb_node **rb_parents = NULL, ***rb_links = NULL;
1372 char *new_row_index = NULL;
1373 struct osl_object *volatile_objs = NULL;
1374 const struct osl_column_description *cd;
1375
1376 if (!t)
1377 return -E_BAD_TABLE;
1378 rb_parents = para_malloc(t->num_rbtrees * sizeof(struct rn_node*));
1379 rb_links = para_malloc(t->num_rbtrees * sizeof(struct rn_node**));
1380 if (t->num_mapped_columns)
1381 new_row_index = para_malloc(t->row_index_size);
1382 /* pass 1: sanity checks */
1383 // DEBUG_LOG("sanity tests: %p:%p\n", objects[0].data,
1384 // objects[1].data);
1385 FOR_EACH_COLUMN(i, t->desc, cd) {
1386 enum osl_storage_type st = cd->storage_type;
1387 enum osl_storage_flags sf = cd->storage_flags;
1388
1389 // ret = -E_NULL_OBJECT;
1390 // if (!objects[i])
1391 // goto out;
1392 if (st == OSL_DISK_STORAGE)
1393 continue;
1394 if (sf & OSL_RBTREE) {
1395 unsigned rbtree_num = t->columns[i].rbtree_num;
1396 ret = -E_RB_KEY_EXISTS;
1397 // DEBUG_LOG("checking whether %p exists\n",
1398 // objects[i].data);
1399 if (search_rbtree(objects + i, t, i,
1400 &rb_parents[rbtree_num],
1401 &rb_links[rbtree_num]) > 0)
1402 goto out;
1403 }
1404 if (sf & OSL_FIXED_SIZE) {
1405 // DEBUG_LOG("fixed size. need: %zu, have: %d\n",
1406 // objects[i].size, cd->data_size);
1407 ret = -E_BAD_DATA_SIZE;
1408 if (objects[i].size != cd->data_size)
1409 goto out;
1410 }
1411 }
1412 if (t->num_disk_storage_columns)
1413 ds_name = disk_storage_name_of_object(t,
1414 &objects[t->disk_storage_name_column]);
1415 ret = unmap_table(t, OSL_MARK_CLEAN);
1416 if (ret < 0)
1417 goto out;
1418 // DEBUG_LOG("sanity tests passed%s\n", "");
1419 /* pass 2: create data files, append map data */
1420 FOR_EACH_COLUMN(i, t->desc, cd) {
1421 enum osl_storage_type st = cd->storage_type;
1422 if (st == OSL_NO_STORAGE)
1423 continue;
1424 if (st == OSL_MAPPED_STORAGE) {
1425 uint32_t new_size;
1426 struct osl_column *col = &t->columns[i];
1427 // DEBUG_LOG("appending object of size %zu\n",
1428 // objects[i].size);
1429 ret = append_map_file(t, i, objects + i, &new_size);
1430 if (ret < 0)
1431 goto rollback;
1432 update_cell_index(new_row_index, col, new_size,
1433 objects[i].size);
1434 continue;
1435 }
1436 /* DISK_STORAGE */
1437 ret = write_disk_storage_file(t, i, objects + i, ds_name);
1438 if (ret < 0)
1439 goto rollback;
1440 }
1441 ret = append_row_index(t, new_row_index);
1442 if (ret < 0)
1443 goto rollback;
1444 ret = map_table(t, MAP_TBL_FL_VERIFY_INDEX);
1445 if (ret < 0) { /* truncate index and rollback changes */
1446 char *filename = index_filename(t->desc);
1447 para_truncate(filename, t->row_index_size);
1448 free(filename);
1449 goto rollback;
1450 }
1451 /* pass 3: add entry to rbtrees */
1452 if (t->num_volatile_columns) {
1453 volatile_objs = para_calloc(t->num_volatile_columns
1454 * sizeof(struct osl_object));
1455 FOR_EACH_VOLATILE_COLUMN(i, t, cd)
1456 volatile_objs[t->columns[i].volatile_num] = objects[i];
1457 }
1458 t->num_rows++;
1459 // DEBUG_LOG("adding new entry as row #%d\n", t->num_rows - 1);
1460 ret = add_row_to_rbtrees(t, t->num_rows - 1, volatile_objs, row);
1461 if (ret < 0)
1462 goto out;
1463 // DEBUG_LOG("added new entry as row #%d\n", t->num_rows - 1);
1464 ret = 1;
1465 goto out;
1466 rollback: /* rollback all changes made, ignore further errors */
1467 for (i--; i >= 0; i--) {
1468 cd = get_column_description(t->desc, i);
1469 enum osl_storage_type st = cd->storage_type;
1470 if (st == OSL_NO_STORAGE)
1471 continue;
1472
1473 if (st == OSL_MAPPED_STORAGE)
1474 truncate_mapped_file(t, i, objects[i].size);
1475 else /* disk storage */
1476 delete_disk_storage_file(t, i, ds_name);
1477 }
1478 /* ignore error and return previous error value */
1479 map_table(t, MAP_TBL_FL_VERIFY_INDEX);
1480 out:
1481 free(new_row_index);
1482 free(ds_name);
1483 free(rb_parents);
1484 free(rb_links);
1485 return ret;
1486 }
1487
1488 /**
1489 * Add a new row to an osl table.
1490 *
1491 * \param t Same meaning as osl_add_and_get_row().
1492 * \param objects Same meaning as osl_add_and_get_row().
1493 *
1494 * \return The return value of the underlying call to osl_add_and_get_row().
1495 *
1496 * This is equivalent to osl_add_and_get_row(t, objects, NULL).
1497 */
1498 int osl_add_row(struct osl_table *t, struct osl_object *objects)
1499 {
1500 return osl_add_and_get_row(t, objects, NULL);
1501 }
1502
1503 /**
1504 * Retrieve an object identified by row and column
1505 *
1506 * \param t Pointer to an open osl table.
1507 * \param r Pointer to the row.
1508 * \param col_num The column number.
1509 * \param object The result pointer.
1510 *
1511 * The column determined by \a col_num must be of type \p OSL_MAPPED_STORAGE
1512 * or \p OSL_NO_STORAGE, i.e. no disk storage objects may be retrieved by this
1513 * function.
1514 *
1515 * \return Positive if object was found, negative on errors. Possible errors
1516 * include: \p E_BAD_TABLE, \p E_BAD_STORAGE_TYPE.
1517 *
1518 * \sa osl_storage_type, osl_open_disk_object().
1519 */
1520 int osl_get_object(const struct osl_table *t, const struct osl_row *r,
1521 unsigned col_num, struct osl_object *object)
1522 {
1523 const struct osl_column_description *cd;
1524
1525 if (!t)
1526 return -E_BAD_TABLE;
1527 cd = get_column_description(t->desc, col_num);
1528 /* col must not be disk storage */
1529 if (cd->storage_type == OSL_DISK_STORAGE)
1530 return -E_BAD_STORAGE_TYPE;
1531 if (cd->storage_type == OSL_MAPPED_STORAGE)
1532 return get_mapped_object(t, col_num, r->num, object);
1533 /* volatile */
1534 *object = r->volatile_objects[t->columns[col_num].volatile_num];
1535 return 1;
1536 }
1537
1538 static int mark_mapped_object_invalid(const struct osl_table *t,
1539 uint32_t row_num, unsigned col_num)
1540 {
1541 struct osl_object obj;
1542 char *p;
1543 int ret = get_mapped_object(t, col_num, row_num, &obj);
1544
1545 if (ret < 0)
1546 return ret;
1547 p = obj.data;
1548 p--;
1549 *p = 0xff;
1550 return 1;
1551 }
1552
1553 /**
1554 * Delete a row from an osl table.
1555 *
1556 * \param t Pointer to an open osl table.
1557 * \param row Pointer to the row to delete.
1558 *
1559 * This removes all disk storage objects, removes all rbtree nodes, and frees
1560 * all volatile objects belonging to the given row. For mapped columns, the
1561 * data is merely marked invalid and may be pruned from time to time by
1562 * para_fsck.
1563 *
1564 * \return Positive on success, negative on errors. Possible errors include:
1565 * \p E_BAD_TABLE, errors returned by osl_get_object().
1566 */
1567 int osl_del_row(struct osl_table *t, struct osl_row *row)
1568 {
1569 struct osl_row *r = row;
1570 int i, ret;
1571 const struct osl_column_description *cd;
1572
1573 if (!t)
1574 return -E_BAD_TABLE;
1575 INFO_LOG("deleting row %p\n", row);
1576
1577 if (t->num_disk_storage_columns) {
1578 char *ds_name;
1579 ret = disk_storage_name_of_row(t, r, &ds_name);
1580 if (ret < 0)
1581 goto out;
1582 FOR_EACH_DISK_STORAGE_COLUMN(i, t, cd)
1583 delete_disk_storage_file(t, i, ds_name);
1584 free(ds_name);
1585 }
1586 FOR_EACH_COLUMN(i, t->desc, cd) {
1587 struct osl_column *col = t->columns + i;
1588 enum osl_storage_type st = cd->storage_type;
1589 remove_rb_node(t, i, r);
1590 if (st == OSL_MAPPED_STORAGE) {
1591 mark_mapped_object_invalid(t, r->num, i);
1592 continue;
1593 }
1594 if (st == OSL_NO_STORAGE && !(cd->storage_flags & OSL_DONT_FREE))
1595 free(r->volatile_objects[col->volatile_num].data);
1596 }
1597 if (t->num_mapped_columns) {
1598 ret = mark_row_invalid(t, r->num);
1599 if (ret < 0)
1600 goto out;
1601 t->num_invalid_rows++;
1602 } else
1603 t->num_rows--;
1604 ret = 1;
1605 out:
1606 free(r->volatile_objects);
1607 free(r);
1608 return ret;
1609 }
1610
1611 /* test if column has an rbtree */
1612 static int check_rbtree_col(const struct osl_table *t, unsigned col_num,
1613 struct osl_column **col)
1614 {
1615 if (!t)
1616 return -E_BAD_TABLE;
1617 if (!(get_column_description(t->desc, col_num)->storage_flags & OSL_RBTREE))
1618 return -E_BAD_STORAGE_FLAGS;
1619 *col = t->columns + col_num;
1620 return 1;
1621 }
1622
1623 /**
1624 * Get the row that contains the given object.
1625 *
1626 * \param t Pointer to an open osl table.
1627 * \param col_num The number of the column to be searched.
1628 * \param obj The object to be looked up.
1629 * \param result Points to the row containing \a obj.
1630 *
1631 * Lookup \a obj in \a t and return the row containing \a obj. The column
1632 * specified by \a col_num must have an associated rbtree.
1633 *
1634 * \return Positive on success, negative on errors. If an error occurred, \a
1635 * result is set to \p NULL. Possible errors include: \p E_BAD_TABLE, \p
1636 * E_BAD_STORAGE_FLAGS, errors returned by get_mapped_object(), \p
1637 * E_RB_KEY_NOT_FOUND.
1638 *
1639 * \sa osl_storage_flags
1640 */
1641 int osl_get_row(const struct osl_table *t, unsigned col_num,
1642 const struct osl_object *obj, struct osl_row **result)
1643 {
1644 int ret;
1645 struct rb_node *node;
1646 struct osl_row *row;
1647 struct osl_column *col;
1648
1649 *result = NULL;
1650 ret = check_rbtree_col(t, col_num, &col);
1651 if (ret < 0)
1652 return ret;
1653 ret = search_rbtree(obj, t, col_num, &node, NULL);
1654 if (ret < 0)
1655 return ret;
1656 row = get_row_pointer(node, t->columns[col_num].rbtree_num);
1657 *result = row;
1658 return 1;
1659 }
1660
1661 static int rbtree_loop(struct osl_column *col, void *private_data,
1662 osl_rbtree_loop_func *func)
1663 {
1664 struct rb_node *n, *tmp;
1665
1666 /* this for-loop is safe against removal of an entry */
1667 for (n = rb_first(&col->rbtree), tmp = n? rb_next(n) : NULL;
1668 n;
1669 n = tmp, tmp = tmp? rb_next(tmp) : NULL) {
1670 struct osl_row *r = get_row_pointer(n, col->rbtree_num);
1671 int ret = func(r, private_data);
1672 if (ret < 0)
1673 return ret;
1674 }
1675 return 1;
1676 }
1677
1678 static int rbtree_loop_reverse(struct osl_column *col, void *private_data,
1679 osl_rbtree_loop_func *func)
1680 {
1681 struct rb_node *n, *tmp;
1682
1683 /* safe against removal of an entry */
1684 for (n = rb_last(&col->rbtree), tmp = n? rb_prev(n) : NULL;
1685 n;
1686 n = tmp, tmp = tmp? rb_prev(tmp) : NULL) {
1687 struct osl_row *r = get_row_pointer(n, col->rbtree_num);
1688 int ret = func(r, private_data);
1689 if (ret < 0)
1690 return ret;
1691 }
1692 return 1;
1693 }
1694
1695 /**
1696 * Loop over all nodes in an rbtree.
1697 *
1698 * \param t Pointer to an open osl table.
1699 * \param col_num The column to use for iterating over the elements.
1700 * \param private_data Pointer that gets passed to \a func.
1701 * \param func The function to be called for each node in the rbtree.
1702 *
1703 * This function does an in-order walk of the rbtree associated with \a
1704 * col_num. It is an error if the \p OSL_RBTREE flag is not set for this
1705 * column. For each node in the rbtree, the given function \a func is called
1706 * with two pointers as arguments: The first osl_row* argument points to the
1707 * row that contains the object corresponding to the rbtree node currently
1708 * traversed, and the \a private_data pointer is passed verbatim to \a func as the
1709 * second argument. The loop terminates either if \a func returns a negative
1710 * value, or if all nodes of the tree have been visited.
1711 *
1712 *
1713 * \return Positive on success, negative on errors. If the termination of the
1714 * loop was caused by \a func returning a negative value, this value is
1715 * returned.
1716 *
1717 * \sa osl_storage_flags, osl_rbtree_loop_reverse(), osl_compare_func.
1718 */
1719 int osl_rbtree_loop(const struct osl_table *t, unsigned col_num,
1720 void *private_data, osl_rbtree_loop_func *func)
1721 {
1722 struct osl_column *col;
1723
1724 int ret = check_rbtree_col(t, col_num, &col);
1725 if (ret < 0)
1726 return ret;
1727 return rbtree_loop(col, private_data, func);
1728 }
1729
1730 /**
1731 * Loop over all nodes in an rbtree in reverse order.
1732 *
1733 * \param t Identical meaning as in \p osl_rbtree_loop().
1734 * \param col_num Identical meaning as in \p osl_rbtree_loop().
1735 * \param private_data Identical meaning as in \p osl_rbtree_loop().
1736 * \param func Identical meaning as in \p osl_rbtree_loop().
1737 *
1738 * This function is identical to \p osl_rbtree_loop(), the only difference
1739 * is that the tree is walked in reverse order.
1740 *
1741 * \return The same return value as \p osl_rbtree_loop().
1742 *
1743 * \sa osl_rbtree_loop().
1744 */
1745 int osl_rbtree_loop_reverse(const struct osl_table *t, unsigned col_num,
1746 void *private_data, osl_rbtree_loop_func *func)
1747 {
1748 struct osl_column *col;
1749
1750 int ret = check_rbtree_col(t, col_num, &col);
1751 if (ret < 0)
1752 return ret;
1753 return rbtree_loop_reverse(col, private_data, func);
1754 }
1755
1756 /* TODO: Rollback changes on errors */
1757 static int rename_disk_storage_objects(struct osl_table *t,
1758 struct osl_object *old_obj, struct osl_object *new_obj)
1759 {
1760 int i, ret;
1761 const struct osl_column_description *cd;
1762 char *old_ds_name, *new_ds_name;
1763
1764 if (!t->num_disk_storage_columns)
1765 return 1; /* nothing to do */
1766 if (old_obj->size == new_obj->size && !memcmp(new_obj->data,
1767 old_obj->data, new_obj->size))
1768 return 1; /* object did not change */
1769 old_ds_name = disk_storage_name_of_object(t, old_obj);
1770 new_ds_name = disk_storage_name_of_object(t, new_obj);
1771 FOR_EACH_DISK_STORAGE_COLUMN(i, t, cd) {
1772 char *old_filename, *new_filename;
1773 ret = create_disk_storage_object_dir(t, i, new_ds_name);
1774 if (ret < 0)
1775 goto out;
1776 old_filename = disk_storage_path(t, i, old_ds_name);
1777 new_filename = disk_storage_path(t, i, new_ds_name);
1778 ret = para_rename(old_filename, new_filename);
1779 free(old_filename);
1780 free(new_filename);
1781 if (ret < 0)
1782 goto out;
1783 }
1784 ret = 1;
1785 out:
1786 free(old_ds_name);
1787 free(new_ds_name);
1788 return ret;
1789
1790 }
1791
1792 /**
1793 * Change an object in an osl table.
1794 *
1795 * \param t Pointer to an open osl table.
1796 * \param r Pointer to the row containing the object to be updated.
1797 * \param col_num Number of the column containing the object to be updated.
1798 * \param obj Pointer to the replacement object.
1799 *
1800 * This function gets rid of all references to the old object. This includes
1801 * removal of the rbtree node in case there is an rbtree associated with \a
1802 * col_num. It then inserts \a obj into the table and the rbtree if necessary.
1803 *
1804 * If the \p OSL_RBTREE flag is set for \a col_num, you \b MUST call this
1805 * function in order to change the contents of an object, even for volatile or
1806 * mapped columns of constant size (which may be updated directly if \p
1807 * OSL_RBTREE is not set). Otherwise the rbtree might become corrupted.
1808 *
1809 * \return Standard
1810 */
1811 int osl_update_object(struct osl_table *t, const struct osl_row *r,
1812 unsigned col_num, struct osl_object *obj)
1813 {
1814 struct osl_column *col;
1815 const struct osl_column_description *cd;
1816 int ret;
1817
1818 if (!t)
1819 return -E_BAD_TABLE;
1820 col = &t->columns[col_num];
1821 cd = get_column_description(t->desc, col_num);
1822 DEBUG_LOG("updating column %u of %s\n", col_num, t->desc->name);
1823 if (cd->storage_flags & OSL_RBTREE) {
1824 if (search_rbtree(obj, t, col_num, NULL, NULL) > 0)
1825 return -E_RB_KEY_EXISTS;
1826 }
1827 if (cd->storage_flags & OSL_FIXED_SIZE) {
1828 if (obj->size != cd->data_size)
1829 return -E_BAD_DATA_SIZE;
1830 }
1831 remove_rb_node(t, col_num, r);
1832 if (cd->storage_type == OSL_NO_STORAGE) { /* TODO: If fixed size, reuse object? */
1833 free(r->volatile_objects[col->volatile_num].data);
1834 r->volatile_objects[col->volatile_num] = *obj;
1835 } else if (cd->storage_type == OSL_DISK_STORAGE) {
1836 char *ds_name;
1837 ret = disk_storage_name_of_row(t, r, &ds_name);
1838 if (ret < 0)
1839 return ret;
1840 ret = delete_disk_storage_file(t, col_num, ds_name);
1841 if (ret < 0 && !is_errno(-ret, ENOENT)) {
1842 free(ds_name);
1843 return ret;
1844 }
1845 ret = write_disk_storage_file(t, col_num, obj, ds_name);
1846 free(ds_name);
1847 if (ret < 0)
1848 return ret;
1849 } else { /* mapped storage */
1850 struct osl_object old_obj;
1851 ret = get_mapped_object(t, col_num, r->num, &old_obj);
1852 if (ret < 0)
1853 return ret;
1854 /*
1855 * If the updated column is the disk storage name column, the
1856 * disk storage name changes, so we have to rename all disk
1857 * storage objects accordingly.
1858 */
1859 if (col_num == t->disk_storage_name_column) {
1860 ret = rename_disk_storage_objects(t, &old_obj, obj);
1861 if (ret < 0)
1862 return ret;
1863 }
1864 if (cd->storage_flags & OSL_FIXED_SIZE)
1865 memcpy(old_obj.data, obj->data, cd->data_size);
1866 else { /* TODO: if the size doesn't change, use old space */
1867 uint32_t new_data_map_size;
1868 char *row_index;
1869 ret = get_row_index(t, r->num, &row_index);
1870 if (ret < 0)
1871 return ret;
1872 ret = mark_mapped_object_invalid(t, r->num, col_num);
1873 if (ret < 0)
1874 return ret;
1875 unmap_column(t, col_num);
1876 ret = append_map_file(t, col_num, obj,
1877 &new_data_map_size);
1878 if (ret < 0)
1879 return ret;
1880 ret = map_column(t, col_num);
1881 if (ret < 0)
1882 return ret;
1883 update_cell_index(row_index, col, new_data_map_size,
1884 obj->size);
1885 }
1886 }
1887 if (cd->storage_flags & OSL_RBTREE) {
1888 ret = insert_rbtree(t, col_num, r, obj);
1889 if (ret < 0)
1890 return ret;
1891 }
1892 return 1;
1893 }
1894
1895 /**
1896 * Retrieve an object of type \p OSL_DISK_STORAGE by row and column.
1897 *
1898 * \param t Pointer to an open osl table.
1899 * \param r Pointer to the row containing the object.
1900 * \param col_num The column number.
1901 * \param obj Points to the result upon successful return.
1902 *
1903 * For columns of type \p OSL_DISK_STORAGE, this function must be used to
1904 * retrieve one of its containing objects. Afterwards, osl_close_disk_object()
1905 * must be called in order to deallocate the resources.
1906 *
1907 * \return Positive on success, negative on errors. Possible errors include:
1908 * \p E_BAD_TABLE, \p E_BAD_STORAGE_TYPE, errors returned by osl_get_object().
1909 *
1910 * \sa osl_get_object(), osl_storage_type, osl_close_disk_object().
1911 */
1912 int osl_open_disk_object(const struct osl_table *t, const struct osl_row *r,
1913 unsigned col_num, struct osl_object *obj)
1914 {
1915 const struct osl_column_description *cd;
1916 char *ds_name, *filename;
1917 int ret;
1918
1919 if (!t)
1920 return -E_BAD_TABLE;
1921 cd = get_column_description(t->desc, col_num);
1922 if (cd->storage_type != OSL_DISK_STORAGE)
1923 return -E_BAD_STORAGE_TYPE;
1924
1925 ret = disk_storage_name_of_row(t, r, &ds_name);
1926 if (ret < 0)
1927 return ret;
1928 filename = disk_storage_path(t, col_num, ds_name);
1929 free(ds_name);
1930 DEBUG_LOG("filename: %s\n", filename);
1931 ret = mmap_full_file(filename, O_RDONLY, &obj->data, &obj->size, NULL);
1932 free(filename);
1933 return ret;
1934 }
1935
1936 /**
1937 * Free resources that were allocated during osl_open_disk_object().
1938 *
1939 * \param obj Pointer to the object previously returned by open_disk_object().
1940 *
1941 * \return The return value of the underlying call to para_munmap().
1942 *
1943 * \sa para_munmap().
1944 */
1945 int osl_close_disk_object(struct osl_object *obj)
1946 {
1947 return para_munmap(obj->data, obj->size);
1948 }
1949
1950 /**
1951 * Get the number of rows of the given table.
1952 *
1953 * \param t Pointer to an open osl table.
1954 * \param num_rows Result is returned here.
1955 *
1956 * The number of rows returned via \a num_rows excluding any invalid rows.
1957 *
1958 * \return Positive on success, \p -E_BAD_TABLE if \a t is \p NULL.
1959 */
1960 int osl_get_num_rows(const struct osl_table *t, unsigned *num_rows)
1961 {
1962 if (!t)
1963 return -E_BAD_TABLE;
1964 assert(t->num_rows >= t->num_invalid_rows);
1965 *num_rows = t->num_rows - t->num_invalid_rows;
1966 return 1;
1967 }
1968
1969 /**
1970 * Get the rank of a row.
1971 *
1972 * \param t An open osl table.
1973 * \param r The row to get the rank of.
1974 * \param col_num The number of an rbtree column.
1975 * \param rank Result pointer.
1976 *
1977 * The rank is, by definition, the position of the row in the linear order
1978 * determined by an in-order tree walk of the rbtree associated with column
1979 * number \a col_num of \a table.
1980 *
1981 * \return Positive on success, negative on errors.
1982 *
1983 * \sa osl_get_nth_row().
1984 */
1985 int osl_get_rank(const struct osl_table *t, struct osl_row *r,
1986 unsigned col_num, unsigned *rank)
1987 {
1988 struct osl_object obj;
1989 struct osl_column *col;
1990 struct rb_node *node;
1991 int ret = check_rbtree_col(t, col_num, &col);
1992
1993 if (ret < 0)
1994 return ret;
1995 ret = osl_get_object(t, r, col_num, &obj);
1996 if (ret < 0)
1997 return ret;
1998 ret = search_rbtree(&obj, t, col_num, &node, NULL);
1999 if (ret < 0)
2000 return ret;
2001 ret = rb_rank(node, rank);
2002 if (ret < 0)
2003 return -E_BAD_ROW;
2004 return 1;
2005 }
2006
2007 /**
2008 * Get the row with n-th greatest value.
2009 *
2010 * \param t Pointer to an open osl table.
2011 * \param col_num The column number.
2012 * \param n The rank of the desired row.
2013 * \param result Row is returned here.
2014 *
2015 * Retrieve the n-th order statistic with respect to the compare function
2016 * of the rbtree column \a col_num. In other words, get that row with
2017 * \a n th greatest value in column \a col_num. It's an error if
2018 * \a col_num is not a rbtree column, or if \a n is larger than the
2019 * number of rows in the table.
2020 *
2021 * \return Positive on success, negative on errors. Possible errors:
2022 * \p E_BAD_TABLE, \p E_BAD_STORAGE_FLAGS, \p E_RB_KEY_NOT_FOUND.
2023 *
2024 * \sa osl_storage_flags, osl_compare_func, osl_get_row(),
2025 * osl_rbtree_last_row(), osl_rbtree_first_row(), osl_get_rank().
2026 */
2027 int osl_get_nth_row(const struct osl_table *t, unsigned col_num,
2028 unsigned n, struct osl_row **result)
2029 {
2030 struct osl_column *col;
2031 struct rb_node *node;
2032 unsigned num_rows;
2033 int ret;
2034
2035 if (n == 0)
2036 return -E_RB_KEY_NOT_FOUND;
2037 ret = osl_get_num_rows(t, &num_rows);
2038 if (ret < 0)
2039 return ret;
2040 if (n > num_rows)
2041 return -E_RB_KEY_NOT_FOUND;
2042 ret = check_rbtree_col(t, col_num, &col);
2043 if (ret < 0)
2044 return ret;
2045 node = rb_nth(col->rbtree.rb_node, n);
2046 if (!node)
2047 return -E_RB_KEY_NOT_FOUND;
2048 *result = get_row_pointer(node, col->rbtree_num);
2049 return 1;
2050 }
2051
2052 /**
2053 * Get the row corresponding to the smallest rbtree node of a column.
2054 *
2055 * \param t An open rbtree table.
2056 * \param col_num The number of the rbtree column.
2057 * \param result A pointer to the first row is returned here.
2058 *
2059 * The rbtree node of the smallest object (with respect to the corresponding
2060 * compare function) is selected and the row containing this object is
2061 * returned. It is an error if \a col_num refers to a column without an
2062 * associated rbtree.
2063 *
2064 * \return Positive on success, negative on errors.
2065 *
2066 * \sa osl_get_nth_row(), osl_rbtree_last_row().
2067 */
2068 int osl_rbtree_first_row(const struct osl_table *t, unsigned col_num,
2069 struct osl_row **result)
2070 {
2071 return osl_get_nth_row(t, col_num, 1, result);
2072 }
2073
2074 /**
2075 * Get the row corresponding to the greatest rbtree node of a column.
2076 *
2077 * \param t The same meaning as in \p osl_rbtree_first_row().
2078 * \param col_num The same meaning as in \p osl_rbtree_first_row().
2079 * \param result The same meaning as in \p osl_rbtree_first_row().
2080 *
2081 * This function works just like osl_rbtree_first_row(), the only difference
2082 * is that the row containing the greatest rather than the smallest object is
2083 * returned.
2084 *
2085 * \return Positive on success, negative on errors.
2086 *
2087 * \sa osl_get_nth_row(), osl_rbtree_first_row().
2088 */
2089 int osl_rbtree_last_row(const struct osl_table *t, unsigned col_num,
2090 struct osl_row **result)
2091 {
2092 unsigned num_rows;
2093 int ret = osl_get_num_rows(t, &num_rows);
2094
2095 if (ret < 0)
2096 return ret;
2097 return osl_get_nth_row(t, col_num, num_rows, result);
2098 }