fsck.c: Fix typo.
[paraslash.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 "para.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 // PARA_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 // PARA_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 // PARA_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 // PARA_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 *, const void *), const 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_PARA_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 PARA_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 PARA_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->num_columns = read_u8(buf + IDX_TABLE_FLAGS);
477 desc->flags = read_u8(buf + IDX_TABLE_FLAGS);
478 desc->num_columns = read_u16(buf + IDX_NUM_COLUMNS);
479 PARA_DEBUG_LOG("%u columns\n", desc->num_columns);
480 if (!desc->num_columns)
481 return -E_NO_COLUMNS;
482 header_size = read_u16(buf + IDX_HEADER_SIZE);
483 if (map->size < header_size)
484 return -E_BAD_SIZE;
485 desc->column_descriptions = para_calloc(desc->num_columns
486 * sizeof(struct osl_column_description));
487 offset = IDX_COLUMN_DESCRIPTIONS;
488 FOR_EACH_COLUMN(i, desc, cd) {
489 char *null_byte;
490
491 ret = -E_SHORT_TABLE;
492 if (map->size < offset + MIN_IDX_COLUMN_DESCRIPTION_SIZE) {
493 PARA_ERROR_LOG("map size = %zu < %u = offset + min desc size\n",
494 map->size, offset + MIN_IDX_COLUMN_DESCRIPTION_SIZE);
495 goto err;
496 }
497 cd->storage_type = read_u16(buf + offset + IDX_CD_STORAGE_TYPE);
498 cd->storage_flags = read_u16(buf + offset +
499 IDX_CD_STORAGE_FLAGS);
500 cd->data_size = read_u32(buf + offset + IDX_CD_DATA_SIZE);
501 null_byte = memchr(buf + offset + IDX_CD_NAME, '\0',
502 map->size - offset - IDX_CD_NAME);
503 ret = -E_INDEX_CORRUPTION;
504 if (!null_byte)
505 goto err;
506 cd->name = para_strdup(buf + offset + IDX_CD_NAME);
507 offset += index_column_description_size(cd->name);
508 }
509 if (offset != header_size) {
510 ret = -E_INDEX_CORRUPTION;
511 PARA_ERROR_LOG("real header size = %u != %u = stored header size\n",
512 offset, header_size);
513 goto err;
514 }
515 return 1;
516 err:
517 FOR_EACH_COLUMN(i, desc, cd)
518 free(cd->name);
519 return ret;
520 }
521
522 /*
523 * check whether the table description given by \p t->desc matches the on-disk
524 * table structure stored in the index of \a t.
525 */
526 static int compare_table_descriptions(struct osl_table *t)
527 {
528 int i, ret;
529 struct osl_table_description desc;
530 const struct osl_column_description *cd1, *cd2;
531
532 /* read the on-disk structure into desc */
533 ret = read_table_desc(&t->index_map, &desc);
534 if (ret < 0)
535 return ret;
536 ret = -E_BAD_TABLE_FLAGS;
537 if (desc.flags != t->desc->flags)
538 goto out;
539 ret = -E_BAD_COLUMN_NUM;
540 if (desc.num_columns != t->desc->num_columns)
541 goto out;
542 FOR_EACH_COLUMN(i, t->desc, cd1) {
543 cd2 = get_column_description(&desc, i);
544 ret = -E_BAD_STORAGE_TYPE;
545 if (cd1->storage_type != cd2->storage_type)
546 goto out;
547 ret = -E_BAD_STORAGE_FLAGS;
548 if (cd1->storage_flags != cd2->storage_flags) {
549 PARA_ERROR_LOG("sf1 = %u != %u = sf2\n",
550 cd1->storage_flags, cd2->storage_flags);
551 goto out;
552 }
553 ret = -E_BAD_DATA_SIZE;
554 if (cd1->storage_flags & OSL_FIXED_SIZE)
555 if (cd1->data_size != cd2->data_size)
556 goto out;
557 ret = -E_BAD_COLUMN_NAME;
558 if (strcmp(cd1->name, cd2->name))
559 goto out;
560 }
561 PARA_DEBUG_LOG("table description of '%s' matches on-disk data, good\n",
562 t->desc->name);
563 ret = 1;
564 out:
565 FOR_EACH_COLUMN(i, &desc, cd1)
566 free(cd1->name);
567 free(desc.column_descriptions);
568 return ret;
569 }
570
571 static int create_table_index(struct osl_table *t)
572 {
573 char *buf, *filename;
574 int i, ret;
575 size_t size = t->index_header_size;
576 const struct osl_column_description *cd;
577 unsigned offset;
578
579 PARA_INFO_LOG("creating %zu byte index for table %s\n", size,
580 t->desc->name);
581 buf = para_calloc(size);
582 sprintf(buf + IDX_PARA_MAGIC, "%s", PARA_MAGIC);
583 write_u8(buf + IDX_TABLE_FLAGS, t->desc->flags);
584 write_u8(buf + IDX_DIRTY_FLAG, 0);
585 write_u8(buf + IDX_VERSION, CURRENT_TABLE_VERSION);
586 write_u16(buf + IDX_NUM_COLUMNS, t->desc->num_columns);
587 write_u16(buf + IDX_HEADER_SIZE, t->index_header_size);
588 offset = IDX_COLUMN_DESCRIPTIONS;
589 FOR_EACH_COLUMN(i, t->desc, cd) {
590 write_u16(buf + offset + IDX_CD_STORAGE_TYPE,
591 cd->storage_type);
592 write_u16(buf + offset + IDX_CD_STORAGE_FLAGS,
593 cd->storage_flags);
594 if (cd->storage_flags & OSL_FIXED_SIZE)
595 write_u32(buf + offset + IDX_CD_DATA_SIZE,
596 cd->data_size);
597 strcpy(buf + offset + IDX_CD_NAME, cd->name);
598 offset += index_column_description_size(cd->name);
599 }
600 assert(offset = size);
601 filename = index_filename(t->desc);
602 ret = para_write_file(filename, buf, size);
603 free(buf);
604 free(filename);
605 return ret;
606 }
607
608 /**
609 * Create a new osl table.
610 *
611 * \param desc Pointer to the table description.
612 *
613 * \return Standard.
614 */
615 int osl_create_table(const struct osl_table_description *desc)
616 {
617 const struct osl_column_description *cd;
618 char *table_dir = NULL, *filename;
619 struct osl_table *t;
620 int i, ret = init_table_structure(desc, &t);
621
622 if (ret < 0)
623 return ret;
624 PARA_INFO_LOG("creating %s\n", desc->name);
625 FOR_EACH_COLUMN(i, t->desc, cd) {
626 if (cd->storage_type == OSL_NO_STORAGE)
627 continue;
628 if (!table_dir) {
629 ret = para_mkdir(desc->dir, 0777);
630 if (ret < 0 && !is_errno(-ret, EEXIST))
631 goto out;
632 table_dir = make_message("%s/%s", desc->dir,
633 desc->name);
634 ret = para_mkdir(table_dir, 0777);
635 if (ret < 0)
636 goto out;
637 }
638 filename = column_filename(t, i);
639 PARA_INFO_LOG("filename: %s\n", filename);
640 if (cd->storage_type == OSL_MAPPED_STORAGE) {
641 ret = para_open(filename, O_RDWR | O_CREAT | O_EXCL,
642 0644);
643 free(filename);
644 if (ret < 0)
645 goto out;
646 close(ret);
647 continue;
648 }
649 /* DISK STORAGE */
650 ret = para_mkdir(filename, 0777);
651 free(filename);
652 if (ret < 0)
653 goto out;
654 }
655 if (t->num_mapped_columns) {
656 ret = create_table_index(t);
657 if (ret < 0)
658 goto out;
659 }
660 ret = 1;
661 out:
662 free(table_dir);
663 free(t->columns);
664 free(t);
665 return ret;
666 }
667
668 static int table_is_dirty(struct osl_table *t)
669 {
670 char *buf = (char *)t->index_map.data + IDX_DIRTY_FLAG;
671 uint8_t dirty = read_u8(buf) & 0x1;
672 return !!dirty;
673 }
674
675 static void mark_table_dirty(struct osl_table *t)
676 {
677 char *buf = (char *)t->index_map.data + IDX_DIRTY_FLAG;
678 write_u8(buf, read_u8(buf) | 1);
679 }
680
681 static void mark_table_clean(struct osl_table *t)
682 {
683 char *buf = (char *)t->index_map.data + IDX_DIRTY_FLAG;
684 write_u8(buf, read_u8(buf) & 0xfe);
685 }
686
687 static void unmap_column(struct osl_table *t, unsigned col_num)
688 {
689 struct osl_object map = t->columns[col_num].data_map;
690 int ret;
691 if (!map.data)
692 return;
693 ret = para_munmap(map.data, map.size);
694 assert(ret > 0);
695 map.data = NULL;
696 }
697
698 /**
699 * Unmap all mapped files of an osl table.
700 *
701 * \param t Pointer to a mapped table.
702 * \param flags Options for unmapping.
703 *
704 * \return Positive on success, negative on errors.
705 *
706 * \sa map_table(), enum osl_close_flags, para_munmap().
707 */
708 int unmap_table(struct osl_table *t, enum osl_close_flags flags)
709 {
710 unsigned i;
711 const struct osl_column_description *cd;
712 int ret;
713
714 if (!t->num_mapped_columns) /* can this ever happen? */
715 return 1;
716 PARA_DEBUG_LOG("unmapping table '%s'\n", t->desc->name);
717 if (!t->index_map.data)
718 return -E_NOT_MAPPED;
719 if (flags & OSL_MARK_CLEAN)
720 mark_table_clean(t);
721 ret = para_munmap(t->index_map.data, t->index_map.size);
722 if (ret < 0)
723 return ret;
724 t->index_map.data = NULL;
725 if (!t->num_rows)
726 return 1;
727 FOR_EACH_MAPPED_COLUMN(i, t, cd)
728 unmap_column(t, i);
729 return 1;
730 }
731
732 static int map_column(struct osl_table *t, unsigned col_num)
733 {
734 struct stat statbuf;
735 char *filename = column_filename(t, col_num);
736 int ret = -E_STAT;
737 if (stat(filename, &statbuf) < 0) {
738 free(filename);
739 return ret;
740 }
741 if (!(S_IFREG & statbuf.st_mode)) {
742 free(filename);
743 return ret;
744 }
745 ret = mmap_full_file(filename, O_RDWR,
746 &t->columns[col_num].data_map.data,
747 &t->columns[col_num].data_map.size,
748 NULL);
749 free(filename);
750 return ret;
751 }
752
753 /**
754 * Map the index file and all columns of type \p OSL_MAPPED_STORAGE into memory.
755 *
756 * \param t Pointer to an initialized table structure.
757 * \param flags Mapping options.
758 *
759 * \return Negative return value on errors; on success the number of rows
760 * (including invalid rows) is returned.
761 *
762 * \sa unmap_table(), enum map_table_flags, osl_open_table(), mmap(2).
763 */
764 int map_table(struct osl_table *t, enum map_table_flags flags)
765 {
766 char *filename;
767 const struct osl_column_description *cd;
768 int i = 0, ret, num_rows = 0;
769
770 if (!t->num_mapped_columns)
771 return 0;
772 if (t->index_map.data)
773 return -E_ALREADY_MAPPED;
774 filename = index_filename(t->desc);
775 PARA_DEBUG_LOG("mapping table '%s' (index: %s)\n", t->desc->name, filename);
776 ret = mmap_full_file(filename, flags & MAP_TBL_FL_MAP_RDONLY?
777 O_RDONLY : O_RDWR, &t->index_map.data, &t->index_map.size, NULL);
778 free(filename);
779 if (ret < 0)
780 return ret;
781 if (flags & MAP_TBL_FL_VERIFY_INDEX) {
782 ret = compare_table_descriptions(t);
783 if (ret < 0)
784 goto err;
785 }
786 ret = -E_BUSY;
787 if (!(flags & MAP_TBL_FL_IGNORE_DIRTY)) {
788 if (table_is_dirty(t)) {
789 PARA_ERROR_LOG("%s is dirty\n", t->desc->name);
790 goto err;
791 }
792 }
793 mark_table_dirty(t);
794 num_rows = table_num_rows(t);
795 if (!num_rows)
796 return num_rows;
797 /* map data files */
798 FOR_EACH_MAPPED_COLUMN(i, t, cd) {
799 ret = map_column(t, i);
800 if (ret < 0)
801 goto err;
802 }
803 return num_rows;
804 err: /* unmap what is already mapped */
805 for (i--; i >= 0; i--) {
806 struct osl_object map = t->columns[i].data_map;
807 para_munmap(map.data, map.size);
808 map.data = NULL;
809 }
810 para_munmap(t->index_map.data, t->index_map.size);
811 t->index_map.data = NULL;
812 return ret;
813 }
814
815 /**
816 * Retrieve a mapped object by row and column number.
817 *
818 * \param t Pointer to an open osl table.
819 * \param col_num Number of the mapped column containing the object to retrieve.
820 * \param row_num Number of the row containing the object to retrieve.
821 * \param obj The result is returned here.
822 *
823 * It is considered an error if \a col_num does not refer to a column
824 * of storage type \p OSL_MAPPED_STORAGE.
825 *
826 * \return Positive on success, negative on errors. Possible errors include:
827 * \p E_BAD_ROW_NUM, \p E_INVALID_OBJECT.
828 *
829 * \sa osl_storage_type.
830 */
831 int get_mapped_object(const struct osl_table *t, unsigned col_num,
832 uint32_t row_num, struct osl_object *obj)
833 {
834 struct osl_column *col = &t->columns[col_num];
835 uint32_t offset;
836 char *header;
837 char *cell_index;
838 int ret;
839
840 if (t->num_rows <= row_num)
841 return -E_BAD_ROW_NUM;
842 ret = get_cell_index(t, row_num, col_num, &cell_index);
843 if (ret < 0)
844 return ret;
845 offset = read_u32(cell_index);
846 obj->size = read_u32(cell_index + 4) - 1;
847 header = col->data_map.data + offset;
848 obj->data = header + 1;
849 if (read_u8(header) == 0xff) {
850 PARA_ERROR_LOG("col %u, size %zu, offset %u\n", col_num,
851 obj->size, offset);
852 return -E_INVALID_OBJECT;
853 }
854 return 1;
855 }
856
857 static int search_rbtree(const struct osl_object *obj,
858 const struct osl_table *t, unsigned col_num,
859 struct rb_node **result, struct rb_node ***rb_link)
860 {
861 struct osl_column *col = &t->columns[col_num];
862 struct rb_node **new = &col->rbtree.rb_node, *parent = NULL;
863 const struct osl_column_description *cd =
864 get_column_description(t->desc, col_num);
865 enum osl_storage_type st = cd->storage_type;
866 while (*new) {
867 struct osl_row *this_row = get_row_pointer(*new,
868 col->rbtree_num);
869 int ret;
870 struct osl_object this_obj;
871 parent = *new;
872 if (st == OSL_MAPPED_STORAGE) {
873 ret = get_mapped_object(t, col_num, this_row->num,
874 &this_obj);
875 if (ret < 0)
876 return ret;
877 } else
878 this_obj = this_row->volatile_objects[col->volatile_num];
879 ret = cd->compare_function(obj, &this_obj);
880 if (!ret) {
881 if (result)
882 *result = get_rb_node_pointer(this_row,
883 col->rbtree_num);
884 return 1;
885 }
886 if (ret < 0)
887 new = &((*new)->rb_left);
888 else
889 new = &((*new)->rb_right);
890 }
891 if (result)
892 *result = parent;
893 if (rb_link)
894 *rb_link = new;
895 return -E_RB_KEY_NOT_FOUND;
896 }
897
898 static int insert_rbtree(struct osl_table *t, unsigned col_num,
899 const struct osl_row *row, const struct osl_object *obj)
900 {
901 struct rb_node *parent, **rb_link;
902 unsigned rbtree_num;
903 struct rb_node *n;
904 int ret = search_rbtree(obj, t, col_num, &parent, &rb_link);
905
906 if (ret > 0)
907 return -E_RB_KEY_EXISTS;
908 rbtree_num = t->columns[col_num].rbtree_num;
909 n = get_rb_node_pointer(row, rbtree_num);
910 rb_link_node(n, parent, rb_link);
911 rb_insert_color(n, &t->columns[col_num].rbtree);
912 return 1;
913 }
914
915 static void remove_rb_node(struct osl_table *t, unsigned col_num,
916 const struct osl_row *row)
917 {
918 struct osl_column *col = &t->columns[col_num];
919 const struct osl_column_description *cd =
920 get_column_description(t->desc, col_num);
921 enum osl_storage_flags sf = cd->storage_flags;
922 struct rb_node *victim, *splice_out_node, *tmp;
923 if (!(sf & OSL_RBTREE))
924 return;
925 /*
926 * Which node is removed/spliced out actually depends on how many
927 * children the victim node has: If it has no children, it gets
928 * deleted. If it has one child, it gets spliced out. If it has two
929 * children, its successor (which has at most a right child) gets
930 * spliced out.
931 */
932 victim = get_rb_node_pointer(row, col->rbtree_num);
933 if (victim->rb_left && victim->rb_right)
934 splice_out_node = rb_next(victim);
935 else
936 splice_out_node = victim;
937 /* Go up to the root and decrement the size of each node in the path. */
938 for (tmp = splice_out_node; tmp; tmp = rb_parent(tmp))
939 tmp->size--;
940 rb_erase(victim, &col->rbtree);
941 }
942
943 static int add_row_to_rbtrees(struct osl_table *t, uint32_t row_num,
944 struct osl_object *volatile_objs, struct osl_row **row_ptr)
945 {
946 unsigned i;
947 int ret;
948 struct osl_row *row = allocate_row(t->num_rbtrees);
949 const struct osl_column_description *cd;
950
951 row->num = row_num;
952 row->volatile_objects = volatile_objs;
953 FOR_EACH_RBTREE_COLUMN(i, t, cd) {
954 if (cd->storage_type == OSL_MAPPED_STORAGE) {
955 struct osl_object obj;
956 ret = get_mapped_object(t, i, row_num, &obj);
957 if (ret < 0)
958 goto err;
959 ret = insert_rbtree(t, i, row, &obj);
960 } else { /* volatile */
961 const struct osl_object *obj
962 = volatile_objs + t->columns[i].volatile_num;
963 ret = insert_rbtree(t, i, row, obj);
964 }
965 if (ret < 0)
966 goto err;
967 }
968 if (row_ptr)
969 *row_ptr = row;
970 return 1;
971 err: /* rollback changes, i.e. remove added entries from rbtrees */
972 while (i)
973 remove_rb_node(t, i--, row);
974 free(row);
975 return ret;
976 }
977
978 static void free_volatile_objects(const struct osl_table *t,
979 enum osl_close_flags flags)
980 {
981 int i, j;
982 struct rb_node *n;
983 struct osl_column *rb_col;
984 const struct osl_column_description *cd;
985
986 if (!t->num_volatile_columns)
987 return;
988 /* find the first rbtree column (any will do) */
989 FOR_EACH_RBTREE_COLUMN(i, t, cd)
990 break;
991 rb_col = t->columns + i;
992 /* walk that rbtree and free all volatile objects */
993 for (n = rb_first(&rb_col->rbtree); n; n = rb_next(n)) {
994 struct osl_row *r = get_row_pointer(n, rb_col->rbtree_num);
995 if (flags & OSL_FREE_VOLATILE)
996 FOR_EACH_VOLATILE_COLUMN(j, t, cd) {
997 if (cd->storage_flags & OSL_DONT_FREE)
998 continue;
999 free(r->volatile_objects[
1000 t->columns[j].volatile_num].data);
1001 }
1002 // for (j = 0; j < t->num_volatile_columns; j++)
1003 // free(r->volatile_objects[j].data);
1004 free(r->volatile_objects);
1005 }
1006 }
1007
1008 /**
1009 * Erase all rbtree nodes and free resources.
1010 *
1011 * \param t Pointer to an open osl table.
1012 *
1013 * This function is called by osl_close_table().
1014 */
1015 void clear_rbtrees(struct osl_table *t)
1016 {
1017 const struct osl_column_description *cd;
1018 unsigned i, rbtrees_cleared = 0;
1019
1020 FOR_EACH_RBTREE_COLUMN(i, t, cd) {
1021 struct osl_column *col = &t->columns[i];
1022 struct rb_node *n;
1023 rbtrees_cleared++;
1024 for (n = rb_first(&col->rbtree); n;) {
1025 struct osl_row *r;
1026 rb_erase(n, &col->rbtree);
1027 if (rbtrees_cleared == t->num_rbtrees) {
1028 r = get_row_pointer(n, col->rbtree_num);
1029 n = rb_next(n);
1030 free(r);
1031 } else
1032 n = rb_next(n);
1033 }
1034 }
1035
1036 }
1037
1038 /**
1039 * Close an osl table.
1040 *
1041 * \param t Pointer to the table to be closed.
1042 * \param flags Options for what should be cleaned up.
1043 *
1044 * If osl_open_table() succeeds, the resulting table pointer must later be
1045 * passed to this function in order to flush all changes to the file system and
1046 * to free the resources that were allocated by osl_open_table().
1047 *
1048 * \return Positive on success, negative on errors. Possible errors: \p E_BAD_TABLE,
1049 * errors returned by unmap_table().
1050 *
1051 * \sa osl_open_table(), unmap_table().
1052 */
1053 int osl_close_table(struct osl_table *t, enum osl_close_flags flags)
1054 {
1055 int ret;
1056
1057 if (!t)
1058 return -E_BAD_TABLE;
1059 free_volatile_objects(t, flags);
1060 clear_rbtrees(t);
1061 ret = unmap_table(t, flags);
1062 if (ret < 0)
1063 PARA_ERROR_LOG("unmap_table failed: %d\n", ret);
1064 free(t->columns);
1065 free(t);
1066 return ret;
1067 }
1068
1069 /**
1070 * Find out whether the given row number corresponds to an invalid row.
1071 *
1072 * \param t Pointer to the osl table.
1073 * \param row_num The number of the row in question.
1074 *
1075 * By definition, a row is considered invalid if all its index entries
1076 * are invalid.
1077 *
1078 * \return Positive if \a row_num corresponds to an invalid row,
1079 * zero if it corresponds to a valid row, negative on errors.
1080 */
1081 int row_is_invalid(struct osl_table *t, uint32_t row_num)
1082 {
1083 char *row_index;
1084 int i, ret = get_row_index(t, row_num, &row_index);
1085
1086 if (ret < 0)
1087 return ret;
1088 for (i = 0; i < t->row_index_size; i++) {
1089 if ((unsigned char)row_index[i] != 0xff)
1090 return 0;
1091 }
1092 PARA_INFO_LOG("row %d is invalid\n", row_num);
1093 return 1;
1094 }
1095
1096 /**
1097 * Invalidate a row of an osl table.
1098 *
1099 * \param t Pointer to an open osl table.
1100 * \param row_num Number of the row to mark as invalid.
1101 *
1102 * This function marks each mapped object in the index entry of \a row as
1103 * invalid.
1104 *
1105 * \return Positive on success, negative on errors.
1106 */
1107 int mark_row_invalid(struct osl_table *t, uint32_t row_num)
1108 {
1109 char *row_index;
1110 int ret = get_row_index(t, row_num, &row_index);
1111
1112 if (ret < 0)
1113 return ret;
1114 PARA_INFO_LOG("marking row %d as invalid\n", row_num);
1115 memset(row_index, 0xff, t->row_index_size);
1116 return 1;
1117 }
1118
1119 /**
1120 * Initialize all rbtrees and compute number of invalid rows.
1121 *
1122 * \param t The table containing the rbtrees to be initialized.
1123 *
1124 * \return Positive on success, negative on errors.
1125 */
1126 int init_rbtrees(struct osl_table *t)
1127 {
1128 int i, ret;
1129 const struct osl_column_description *cd;
1130
1131 /* create rbtrees */
1132 FOR_EACH_RBTREE_COLUMN(i, t, cd)
1133 t->columns[i].rbtree = RB_ROOT;
1134 /* add valid rows to rbtrees */
1135 t->num_invalid_rows = 0;
1136 for (i = 0; i < t->num_rows; i++) {
1137 ret = row_is_invalid(t, i);
1138 if (ret < 0)
1139 return ret;
1140 if (ret) {
1141 t->num_invalid_rows++;
1142 continue;
1143 }
1144 ret = add_row_to_rbtrees(t, i, NULL, NULL);
1145 if (ret < 0)
1146 return ret;
1147 }
1148 return 1;
1149 }
1150
1151 /**
1152 * Open an osl table.
1153 *
1154 * Each osl table must be opened before its data can be accessed.
1155 *
1156 * \param table_desc Describes the table to be opened.
1157 * \param result Contains a pointer to the open table on success.
1158 *
1159 * The table description given by \a desc should coincide with the
1160 * description used at creation time.
1161 *
1162 * \return Standard.
1163 */
1164 int osl_open_table(const struct osl_table_description *table_desc,
1165 struct osl_table **result)
1166 {
1167 int i, ret;
1168 struct osl_table *t;
1169 const struct osl_column_description *cd;
1170
1171 PARA_INFO_LOG("opening table %s\n", table_desc->name);
1172 ret = init_table_structure(table_desc, &t);
1173 if (ret < 0)
1174 return ret;
1175 FOR_EACH_DISK_STORAGE_COLUMN(i, t, cd) {
1176 /* check if directory exists */
1177 char *dirname = column_filename(t, i);
1178 struct stat statbuf;
1179 ret = stat(dirname, &statbuf);
1180 free(dirname);
1181 if (ret < 0) {
1182 ret = -ERRNO_TO_PARA_ERROR(errno);
1183 goto err;
1184 }
1185 ret = -ERRNO_TO_PARA_ERROR(ENOTDIR);
1186 if (!S_ISDIR(statbuf.st_mode))
1187 goto err;
1188 }
1189 ret = map_table(t, MAP_TBL_FL_VERIFY_INDEX);
1190 if (ret < 0)
1191 goto err;
1192 t->num_rows = ret;
1193 PARA_DEBUG_LOG("num rows: %d\n", t->num_rows);
1194 ret = init_rbtrees(t);
1195 if (ret < 0) {
1196 osl_close_table(t, OSL_MARK_CLEAN); /* ignore further errors */
1197 return ret;
1198 }
1199 *result = t;
1200 return 1;
1201 err:
1202 free(t->columns);
1203 free(t);
1204 return ret;
1205 }
1206
1207 static int create_disk_storage_object_dir(const struct osl_table *t,
1208 unsigned col_num, const char *ds_name)
1209 {
1210 char *dirname;
1211 int ret;
1212
1213 if (!(t->desc->flags & OSL_LARGE_TABLE))
1214 return 1;
1215 dirname = disk_storage_dirname(t, col_num, ds_name);
1216 ret = para_mkdir(dirname, 0777);
1217 free(dirname);
1218 if (ret < 0 && !is_errno(-ret, EEXIST))
1219 return ret;
1220 return 1;
1221 }
1222
1223 static int write_disk_storage_file(const struct osl_table *t, unsigned col_num,
1224 const struct osl_object *obj, const char *ds_name)
1225 {
1226 int ret;
1227 char *filename;
1228
1229 ret = create_disk_storage_object_dir(t, col_num, ds_name);
1230 if (ret < 0)
1231 return ret;
1232 filename = disk_storage_path(t, col_num, ds_name);
1233 ret = para_write_file(filename, obj->data, obj->size);
1234 free(filename);
1235 return ret;
1236 }
1237
1238 static int append_map_file(const struct osl_table *t, unsigned col_num,
1239 const struct osl_object *obj, uint32_t *new_size)
1240 {
1241 char *filename = column_filename(t, col_num);
1242 int ret;
1243 char header = 0; /* zero means valid object */
1244
1245 // PARA_DEBUG_LOG("appending %zu + 1 byte\n", obj->size);
1246 ret = append_file(filename, &header, 1, obj->data, obj->size,
1247 new_size);
1248 free(filename);
1249 return ret;
1250 }
1251
1252 static int append_row_index(const struct osl_table *t, char *row_index)
1253 {
1254 char *filename;
1255 int ret;
1256
1257 if (!t->num_mapped_columns)
1258 return 1;
1259 filename = index_filename(t->desc);
1260 ret = append_file(filename, NULL, 0, row_index,
1261 t->row_index_size, NULL);
1262 free(filename);
1263 return ret;
1264 }
1265
1266 /**
1267 * A wrapper for truncate(2)
1268 *
1269 * \param path Name of the regular file to truncate
1270 * \param size Number of bytes to \b shave \b off
1271 *
1272 * Truncate the regular file named by \a path by \a size bytes.
1273 *
1274 * \return Positive on success, negative on errors. Possible errors include: \p
1275 * E_STAT, \p E_BAD_SIZE, \p E_TRUNC.
1276 *
1277 * \sa truncate(2)
1278 */
1279 int para_truncate(const char *path, off_t size)
1280 {
1281 int ret;
1282 struct stat statbuf;
1283
1284 ret = -E_STAT;
1285 if (stat(path, &statbuf) < 0)
1286 goto out;
1287 ret = -E_BAD_SIZE;
1288 if (statbuf.st_size < size)
1289 goto out;
1290 ret = -E_TRUNC;
1291 if (truncate(path, statbuf.st_size - size) < 0)
1292 goto out;
1293 ret = 1;
1294 out:
1295 return ret;
1296 }
1297
1298 static int truncate_mapped_file(const struct osl_table *t, unsigned col_num,
1299 off_t size)
1300 {
1301 char *filename = column_filename(t, col_num);
1302 int ret = para_truncate(filename, size);
1303 free(filename);
1304 return ret;
1305 }
1306
1307 static int delete_disk_storage_file(const struct osl_table *t, unsigned col_num,
1308 const char *ds_name)
1309 {
1310 char *dirname, *filename = disk_storage_path(t, col_num, ds_name);
1311 int ret = unlink(filename), err = errno;
1312
1313 free(filename);
1314 if (ret < 0)
1315 return -ERRNO_TO_PARA_ERROR(err);
1316 if (!(t->desc->flags & OSL_LARGE_TABLE))
1317 return 1;
1318 dirname = disk_storage_dirname(t, col_num, ds_name);
1319 rmdir(dirname);
1320 free(dirname);
1321 return 1;
1322 }
1323
1324 /**
1325 * Add a new row to an osl table and retrieve this row.
1326 *
1327 * \param t Pointer to an open osl table.
1328 * \param objects Array of objects to be added.
1329 * \param row Result pointer.
1330 *
1331 * The \a objects parameter must point to an array containing one object per
1332 * column. The order of the objects in the array is given by the table
1333 * description of \a table. Several sanity checks are performed during object
1334 * insertion and the function returns without modifying the table if any of
1335 * these tests fail. In fact, it is atomic in the sense that it either
1336 * succeeds or leaves the table unchanged (i.e. either all or none of the
1337 * objects are added to the table).
1338 *
1339 * It is considered an error if an object is added to a column with associated
1340 * rbtree if this object is equal to an object already contained in that column
1341 * (i.e. the compare function for the column's rbtree returns zero).
1342 *
1343 * Possible errors include: \p E_RB_KEY_EXISTS, \p E_BAD_DATA_SIZE.
1344 *
1345 * \return Positive on success, negative on errors.
1346 *
1347 * \sa struct osl_table_description, osl_compare_func, osl_add_row().
1348 */
1349 int osl_add_and_get_row(struct osl_table *t, struct osl_object *objects,
1350 struct osl_row **row)
1351 {
1352 int i, ret;
1353 char *ds_name = NULL;
1354 struct rb_node **rb_parents = NULL, ***rb_links = NULL;
1355 char *new_row_index = NULL;
1356 struct osl_object *volatile_objs = NULL;
1357 const struct osl_column_description *cd;
1358
1359 if (!t)
1360 return -E_BAD_TABLE;
1361 rb_parents = para_malloc(t->num_rbtrees * sizeof(struct rn_node*));
1362 rb_links = para_malloc(t->num_rbtrees * sizeof(struct rn_node**));
1363 if (t->num_mapped_columns)
1364 new_row_index = para_malloc(t->row_index_size);
1365 /* pass 1: sanity checks */
1366 // PARA_DEBUG_LOG("sanity tests: %p:%p\n", objects[0].data,
1367 // objects[1].data);
1368 FOR_EACH_COLUMN(i, t->desc, cd) {
1369 enum osl_storage_type st = cd->storage_type;
1370 enum osl_storage_flags sf = cd->storage_flags;
1371
1372 // ret = -E_NULL_OBJECT;
1373 // if (!objects[i])
1374 // goto out;
1375 if (st == OSL_DISK_STORAGE)
1376 continue;
1377 if (sf & OSL_RBTREE) {
1378 unsigned rbtree_num = t->columns[i].rbtree_num;
1379 ret = -E_RB_KEY_EXISTS;
1380 // PARA_DEBUG_LOG("checking whether %p exists\n",
1381 // objects[i].data);
1382 if (search_rbtree(objects + i, t, i,
1383 &rb_parents[rbtree_num],
1384 &rb_links[rbtree_num]) > 0)
1385 goto out;
1386 }
1387 if (sf & OSL_FIXED_SIZE) {
1388 // PARA_DEBUG_LOG("fixed size. need: %zu, have: %d\n",
1389 // objects[i].size, cd->data_size);
1390 ret = -E_BAD_DATA_SIZE;
1391 if (objects[i].size != cd->data_size)
1392 goto out;
1393 }
1394 }
1395 if (t->num_disk_storage_columns)
1396 ds_name = disk_storage_name_of_object(t,
1397 &objects[t->disk_storage_name_column]);
1398 ret = unmap_table(t, OSL_MARK_CLEAN);
1399 if (ret < 0)
1400 goto out;
1401 // PARA_DEBUG_LOG("sanity tests passed%s\n", "");
1402 /* pass 2: create data files, append map data */
1403 FOR_EACH_COLUMN(i, t->desc, cd) {
1404 enum osl_storage_type st = cd->storage_type;
1405 if (st == OSL_NO_STORAGE)
1406 continue;
1407 if (st == OSL_MAPPED_STORAGE) {
1408 uint32_t new_size;
1409 struct osl_column *col = &t->columns[i];
1410 // PARA_DEBUG_LOG("appending object of size %zu\n",
1411 // objects[i].size);
1412 ret = append_map_file(t, i, objects + i, &new_size);
1413 if (ret < 0)
1414 goto rollback;
1415 update_cell_index(new_row_index, col, new_size,
1416 objects[i].size);
1417 continue;
1418 }
1419 /* DISK_STORAGE */
1420 ret = write_disk_storage_file(t, i, objects + i, ds_name);
1421 if (ret < 0)
1422 goto rollback;
1423 }
1424 ret = append_row_index(t, new_row_index);
1425 if (ret < 0)
1426 goto rollback;
1427 ret = map_table(t, MAP_TBL_FL_VERIFY_INDEX);
1428 if (ret < 0) { /* truncate index and rollback changes */
1429 char *filename = index_filename(t->desc);
1430 para_truncate(filename, t->row_index_size);
1431 free(filename);
1432 goto rollback;
1433 }
1434 /* pass 3: add entry to rbtrees */
1435 if (t->num_volatile_columns) {
1436 volatile_objs = para_calloc(t->num_volatile_columns
1437 * sizeof(struct osl_object));
1438 FOR_EACH_VOLATILE_COLUMN(i, t, cd)
1439 volatile_objs[t->columns[i].volatile_num] = objects[i];
1440 }
1441 t->num_rows++;
1442 // PARA_DEBUG_LOG("adding new entry as row #%d\n", t->num_rows - 1);
1443 ret = add_row_to_rbtrees(t, t->num_rows - 1, volatile_objs, row);
1444 if (ret < 0)
1445 goto out;
1446 // PARA_DEBUG_LOG("added new entry as row #%d\n", t->num_rows - 1);
1447 ret = 1;
1448 goto out;
1449 rollback: /* rollback all changes made, ignore further errors */
1450 for (i--; i >= 0; i--) {
1451 cd = get_column_description(t->desc, i);
1452 enum osl_storage_type st = cd->storage_type;
1453 if (st == OSL_NO_STORAGE)
1454 continue;
1455
1456 if (st == OSL_MAPPED_STORAGE)
1457 truncate_mapped_file(t, i, objects[i].size);
1458 else /* disk storage */
1459 delete_disk_storage_file(t, i, ds_name);
1460 }
1461 /* ignore error and return previous error value */
1462 map_table(t, MAP_TBL_FL_VERIFY_INDEX);
1463 out:
1464 free(new_row_index);
1465 free(ds_name);
1466 free(rb_parents);
1467 free(rb_links);
1468 return ret;
1469 }
1470
1471 /**
1472 * Add a new row to an osl table.
1473 *
1474 * \param t Same meaning as osl_add_and_get_row().
1475 * \param objects Same meaning as osl_add_and_get_row().
1476 *
1477 * \return The return value of the underlying call to osl_add_and_get_row().
1478 *
1479 * This is equivalent to osl_add_and_get_row(t, objects, NULL).
1480 */
1481 int osl_add_row(struct osl_table *t, struct osl_object *objects)
1482 {
1483 return osl_add_and_get_row(t, objects, NULL);
1484 }
1485
1486 /**
1487 * Retrieve an object identified by row and column
1488 *
1489 * \param t Pointer to an open osl table.
1490 * \param r Pointer to the row.
1491 * \param col_num The column number.
1492 * \param object The result pointer.
1493 *
1494 * The column determined by \a col_num must be of type \p OSL_MAPPED_STORAGE
1495 * or \p OSL_NO_STORAGE, i.e. no disk storage objects may be retrieved by this
1496 * function.
1497 *
1498 * \return Positive if object was found, negative on errors. Possible errors
1499 * include: \p E_BAD_TABLE, \p E_BAD_STORAGE_TYPE.
1500 *
1501 * \sa osl_storage_type, osl_open_disk_object().
1502 */
1503 int osl_get_object(const struct osl_table *t, const struct osl_row *r,
1504 unsigned col_num, struct osl_object *object)
1505 {
1506 const struct osl_column_description *cd;
1507
1508 if (!t)
1509 return -E_BAD_TABLE;
1510 cd = get_column_description(t->desc, col_num);
1511 /* col must not be disk storage */
1512 if (cd->storage_type == OSL_DISK_STORAGE)
1513 return -E_BAD_STORAGE_TYPE;
1514 if (cd->storage_type == OSL_MAPPED_STORAGE)
1515 return get_mapped_object(t, col_num, r->num, object);
1516 /* volatile */
1517 *object = r->volatile_objects[t->columns[col_num].volatile_num];
1518 return 1;
1519 }
1520
1521 static int mark_mapped_object_invalid(const struct osl_table *t,
1522 uint32_t row_num, unsigned col_num)
1523 {
1524 struct osl_object obj;
1525 char *p;
1526 int ret = get_mapped_object(t, col_num, row_num, &obj);
1527
1528 if (ret < 0)
1529 return ret;
1530 p = obj.data;
1531 p--;
1532 *p = 0xff;
1533 return 1;
1534 }
1535
1536 /**
1537 * Delete a row from an osl table.
1538 *
1539 * \param t Pointer to an open osl table.
1540 * \param row Pointer to the row to delete.
1541 *
1542 * This removes all disk storage objects, removes all rbtree nodes, and frees
1543 * all volatile objects belonging to the given row. For mapped columns, the
1544 * data is merely marked invalid and may be pruned from time to time by
1545 * para_fsck.
1546 *
1547 * \return Positive on success, negative on errors. Possible errors include:
1548 * \p E_BAD_TABLE, errors returned by osl_get_object().
1549 */
1550 int osl_del_row(struct osl_table *t, struct osl_row *row)
1551 {
1552 struct osl_row *r = row;
1553 int i, ret;
1554 const struct osl_column_description *cd;
1555
1556 if (!t)
1557 return -E_BAD_TABLE;
1558 PARA_INFO_LOG("deleting row %p\n", row);
1559
1560 if (t->num_disk_storage_columns) {
1561 char *ds_name;
1562 ret = disk_storage_name_of_row(t, r, &ds_name);
1563 if (ret < 0)
1564 goto out;
1565 FOR_EACH_DISK_STORAGE_COLUMN(i, t, cd)
1566 delete_disk_storage_file(t, i, ds_name);
1567 free(ds_name);
1568 }
1569 FOR_EACH_COLUMN(i, t->desc, cd) {
1570 struct osl_column *col = t->columns + i;
1571 enum osl_storage_type st = cd->storage_type;
1572 remove_rb_node(t, i, r);
1573 if (st == OSL_MAPPED_STORAGE) {
1574 mark_mapped_object_invalid(t, r->num, i);
1575 continue;
1576 }
1577 if (st == OSL_NO_STORAGE && !(cd->storage_flags & OSL_DONT_FREE))
1578 free(r->volatile_objects[col->volatile_num].data);
1579 }
1580 if (t->num_mapped_columns) {
1581 ret = mark_row_invalid(t, r->num);
1582 if (ret < 0)
1583 goto out;
1584 t->num_invalid_rows++;
1585 } else
1586 t->num_rows--;
1587 ret = 1;
1588 out:
1589 free(r->volatile_objects);
1590 free(r);
1591 return ret;
1592 }
1593
1594 /* test if column has an rbtree */
1595 static int check_rbtree_col(const struct osl_table *t, unsigned col_num,
1596 struct osl_column **col)
1597 {
1598 if (!t)
1599 return -E_BAD_TABLE;
1600 if (!(get_column_description(t->desc, col_num)->storage_flags & OSL_RBTREE))
1601 return -E_BAD_STORAGE_FLAGS;
1602 *col = t->columns + col_num;
1603 return 1;
1604 }
1605
1606 /**
1607 * Get the row that contains the given object.
1608 *
1609 * \param t Pointer to an open osl table.
1610 * \param col_num The number of the column to be searched.
1611 * \param obj The object to be looked up.
1612 * \param result Points to the row containing \a obj.
1613 *
1614 * Lookup \a obj in \a t and return the row containing \a obj. The column
1615 * specified by \a col_num must have an associated rbtree.
1616 *
1617 * \return Positive on success, negative on errors. If an error occurred, \a
1618 * result is set to \p NULL. Possible errors include: \p E_BAD_TABLE, \p
1619 * E_BAD_STORAGE_FLAGS, errors returned by get_mapped_object(), \p
1620 * E_RB_KEY_NOT_FOUND.
1621 *
1622 * \sa osl_storage_flags
1623 */
1624 int osl_get_row(const struct osl_table *t, unsigned col_num,
1625 const struct osl_object *obj, struct osl_row **result)
1626 {
1627 int ret;
1628 struct rb_node *node;
1629 struct osl_row *row;
1630 struct osl_column *col;
1631
1632 *result = NULL;
1633 ret = check_rbtree_col(t, col_num, &col);
1634 if (ret < 0)
1635 return ret;
1636 ret = search_rbtree(obj, t, col_num, &node, NULL);
1637 if (ret < 0)
1638 return ret;
1639 row = get_row_pointer(node, t->columns[col_num].rbtree_num);
1640 *result = row;
1641 return 1;
1642 }
1643
1644 static int rbtree_loop(struct osl_column *col, void *private_data,
1645 osl_rbtree_loop_func *func)
1646 {
1647 struct rb_node *n, *tmp;
1648
1649 /* this for-loop is safe against removal of an entry */
1650 for (n = rb_first(&col->rbtree), tmp = n? rb_next(n) : NULL;
1651 n;
1652 n = tmp, tmp = tmp? rb_next(tmp) : NULL) {
1653 struct osl_row *r = get_row_pointer(n, col->rbtree_num);
1654 int ret = func(r, private_data);
1655 if (ret < 0)
1656 return ret;
1657 }
1658 return 1;
1659 }
1660
1661 static int rbtree_loop_reverse(struct osl_column *col, void *private_data,
1662 osl_rbtree_loop_func *func)
1663 {
1664 struct rb_node *n, *tmp;
1665
1666 /* safe against removal of an entry */
1667 for (n = rb_last(&col->rbtree), tmp = n? rb_prev(n) : NULL;
1668 n;
1669 n = tmp, tmp = tmp? rb_prev(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 /**
1679 * Loop over all nodes in an rbtree.
1680 *
1681 * \param t Pointer to an open osl table.
1682 * \param col_num The column to use for iterating over the elements.
1683 * \param private_data Pointer that gets passed to \a func.
1684 * \param func The function to be called for each node in the rbtree.
1685 *
1686 * This function does an in-order walk of the rbtree associated with \a
1687 * col_num. It is an error if the \p OSL_RBTREE flag is not set for this
1688 * column. For each node in the rbtree, the given function \a func is called
1689 * with two pointers as arguments: The first osl_row* argument points to the
1690 * row that contains the object corresponding to the rbtree node currently
1691 * traversed, and the \a private_data pointer is passed verbatim to \a func as the
1692 * second argument. The loop terminates either if \a func returns a negative
1693 * value, or if all nodes of the tree have been visited.
1694 *
1695 *
1696 * \return Positive on success, negative on errors. If the termination of the
1697 * loop was caused by \a func returning a negative value, this value is
1698 * returned.
1699 *
1700 * \sa osl_storage_flags, osl_rbtree_loop_reverse(), osl_compare_func.
1701 */
1702 int osl_rbtree_loop(const struct osl_table *t, unsigned col_num,
1703 void *private_data, osl_rbtree_loop_func *func)
1704 {
1705 struct osl_column *col;
1706
1707 int ret = check_rbtree_col(t, col_num, &col);
1708 if (ret < 0)
1709 return ret;
1710 return rbtree_loop(col, private_data, func);
1711 }
1712
1713 /**
1714 * Loop over all nodes in an rbtree in reverse order.
1715 *
1716 * \param t Identical meaning as in \p osl_rbtree_loop().
1717 * \param col_num Identical meaning as in \p osl_rbtree_loop().
1718 * \param private_data Identical meaning as in \p osl_rbtree_loop().
1719 * \param func Identical meaning as in \p osl_rbtree_loop().
1720 *
1721 * This function is identical to \p osl_rbtree_loop(), the only difference
1722 * is that the tree is walked in reverse order.
1723 *
1724 * \return The same return value as \p osl_rbtree_loop().
1725 *
1726 * \sa osl_rbtree_loop().
1727 */
1728 int osl_rbtree_loop_reverse(const struct osl_table *t, unsigned col_num,
1729 void *private_data, osl_rbtree_loop_func *func)
1730 {
1731 struct osl_column *col;
1732
1733 int ret = check_rbtree_col(t, col_num, &col);
1734 if (ret < 0)
1735 return ret;
1736 return rbtree_loop_reverse(col, private_data, func);
1737 }
1738
1739 /* TODO: Rollback changes on errors */
1740 static int rename_disk_storage_objects(struct osl_table *t,
1741 struct osl_object *old_obj, struct osl_object *new_obj)
1742 {
1743 int i, ret;
1744 const struct osl_column_description *cd;
1745 char *old_ds_name, *new_ds_name;
1746
1747 if (!t->num_disk_storage_columns)
1748 return 1; /* nothing to do */
1749 if (old_obj->size == new_obj->size && !memcmp(new_obj->data,
1750 old_obj->data, new_obj->size))
1751 return 1; /* object did not change */
1752 old_ds_name = disk_storage_name_of_object(t, old_obj);
1753 new_ds_name = disk_storage_name_of_object(t, new_obj);
1754 FOR_EACH_DISK_STORAGE_COLUMN(i, t, cd) {
1755 char *old_filename, *new_filename;
1756 ret = create_disk_storage_object_dir(t, i, new_ds_name);
1757 if (ret < 0)
1758 goto out;
1759 old_filename = disk_storage_path(t, i, old_ds_name);
1760 new_filename = disk_storage_path(t, i, new_ds_name);
1761 ret = para_rename(old_filename, new_filename);
1762 free(old_filename);
1763 free(new_filename);
1764 if (ret < 0)
1765 goto out;
1766 }
1767 ret = 1;
1768 out:
1769 free(old_ds_name);
1770 free(new_ds_name);
1771 return ret;
1772
1773 }
1774
1775 /**
1776 * Change an object in an osl table.
1777 *
1778 * \param t Pointer to an open osl table.
1779 * \param r Pointer to the row containing the object to be updated.
1780 * \param col_num Number of the column containing the object to be updated.
1781 * \param obj Pointer to the replacement object.
1782 *
1783 * This function gets rid of all references to the old object. This includes
1784 * removal of the rbtree node in case there is an rbtree associated with \a
1785 * col_num. It then inserts \a obj into the table and the rbtree if necessary.
1786 *
1787 * If the \p OSL_RBTREE flag is set for \a col_num, you \b MUST call this
1788 * function in order to change the contents of an object, even for volatile or
1789 * mapped columns of constant size (which may be updated directly if \p
1790 * OSL_RBTREE is not set). Otherwise the rbtree might become corrupted.
1791 *
1792 * \return Standard
1793 */
1794 int osl_update_object(struct osl_table *t, const struct osl_row *r,
1795 unsigned col_num, struct osl_object *obj)
1796 {
1797 struct osl_column *col;
1798 const struct osl_column_description *cd;
1799 int ret;
1800
1801 if (!t)
1802 return -E_BAD_TABLE;
1803 col = &t->columns[col_num];
1804 cd = get_column_description(t->desc, col_num);
1805 PARA_DEBUG_LOG("updating column %u of %s\n", col_num, t->desc->name);
1806 if (cd->storage_flags & OSL_RBTREE) {
1807 if (search_rbtree(obj, t, col_num, NULL, NULL) > 0)
1808 return -E_RB_KEY_EXISTS;
1809 }
1810 if (cd->storage_flags & OSL_FIXED_SIZE) {
1811 if (obj->size != cd->data_size)
1812 return -E_BAD_DATA_SIZE;
1813 }
1814 remove_rb_node(t, col_num, r);
1815 if (cd->storage_type == OSL_NO_STORAGE) { /* TODO: If fixed size, reuse object? */
1816 free(r->volatile_objects[col->volatile_num].data);
1817 r->volatile_objects[col->volatile_num] = *obj;
1818 } else if (cd->storage_type == OSL_DISK_STORAGE) {
1819 char *ds_name;
1820 ret = disk_storage_name_of_row(t, r, &ds_name);
1821 if (ret < 0)
1822 return ret;
1823 ret = delete_disk_storage_file(t, col_num, ds_name);
1824 if (ret < 0 && !is_errno(-ret, ENOENT)) {
1825 free(ds_name);
1826 return ret;
1827 }
1828 ret = write_disk_storage_file(t, col_num, obj, ds_name);
1829 free(ds_name);
1830 if (ret < 0)
1831 return ret;
1832 } else { /* mapped storage */
1833 struct osl_object old_obj;
1834 ret = get_mapped_object(t, col_num, r->num, &old_obj);
1835 if (ret < 0)
1836 return ret;
1837 /*
1838 * If the updated column is the disk storage name column, the
1839 * disk storage name changes, so we have to rename all disk
1840 * storage objects accordingly.
1841 */
1842 if (col_num == t->disk_storage_name_column) {
1843 ret = rename_disk_storage_objects(t, &old_obj, obj);
1844 if (ret < 0)
1845 return ret;
1846 }
1847 if (cd->storage_flags & OSL_FIXED_SIZE)
1848 memcpy(old_obj.data, obj->data, cd->data_size);
1849 else { /* TODO: if the size doesn't change, use old space */
1850 uint32_t new_data_map_size;
1851 char *row_index;
1852 ret = get_row_index(t, r->num, &row_index);
1853 if (ret < 0)
1854 return ret;
1855 ret = mark_mapped_object_invalid(t, r->num, col_num);
1856 if (ret < 0)
1857 return ret;
1858 unmap_column(t, col_num);
1859 ret = append_map_file(t, col_num, obj,
1860 &new_data_map_size);
1861 if (ret < 0)
1862 return ret;
1863 ret = map_column(t, col_num);
1864 if (ret < 0)
1865 return ret;
1866 update_cell_index(row_index, col, new_data_map_size,
1867 obj->size);
1868 }
1869 }
1870 if (cd->storage_flags & OSL_RBTREE) {
1871 ret = insert_rbtree(t, col_num, r, obj);
1872 if (ret < 0)
1873 return ret;
1874 }
1875 return 1;
1876 }
1877
1878 /**
1879 * Retrieve an object of type \p OSL_DISK_STORAGE by row and column.
1880 *
1881 * \param t Pointer to an open osl table.
1882 * \param r Pointer to the row containing the object.
1883 * \param col_num The column number.
1884 * \param obj Points to the result upon successful return.
1885 *
1886 * For columns of type \p OSL_DISK_STORAGE, this function must be used to
1887 * retrieve one of its containing objects. Afterwards, osl_close_disk_object()
1888 * must be called in order to deallocate the resources.
1889 *
1890 * \return Positive on success, negative on errors. Possible errors include:
1891 * \p E_BAD_TABLE, \p E_BAD_STORAGE_TYPE, errors returned by osl_get_object().
1892 *
1893 * \sa osl_get_object(), osl_storage_type, osl_close_disk_object().
1894 */
1895 int osl_open_disk_object(const struct osl_table *t, const struct osl_row *r,
1896 unsigned col_num, struct osl_object *obj)
1897 {
1898 const struct osl_column_description *cd;
1899 char *ds_name, *filename;
1900 int ret;
1901
1902 if (!t)
1903 return -E_BAD_TABLE;
1904 cd = get_column_description(t->desc, col_num);
1905 if (cd->storage_type != OSL_DISK_STORAGE)
1906 return -E_BAD_STORAGE_TYPE;
1907
1908 ret = disk_storage_name_of_row(t, r, &ds_name);
1909 if (ret < 0)
1910 return ret;
1911 filename = disk_storage_path(t, col_num, ds_name);
1912 free(ds_name);
1913 PARA_DEBUG_LOG("filename: %s\n", filename);
1914 ret = mmap_full_file(filename, O_RDONLY, &obj->data, &obj->size, NULL);
1915 free(filename);
1916 return ret;
1917 }
1918
1919 /**
1920 * Free resources that were allocated during osl_open_disk_object().
1921 *
1922 * \param obj Pointer to the object previously returned by open_disk_object().
1923 *
1924 * \return The return value of the underlying call to para_munmap().
1925 *
1926 * \sa para_munmap().
1927 */
1928 int osl_close_disk_object(struct osl_object *obj)
1929 {
1930 return para_munmap(obj->data, obj->size);
1931 }
1932
1933 /**
1934 * Get the number of rows of the given table.
1935 *
1936 * \param t Pointer to an open osl table.
1937 * \param num_rows Result is returned here.
1938 *
1939 * The number of rows returned via \a num_rows excluding any invalid rows.
1940 *
1941 * \return Positive on success, \p -E_BAD_TABLE if \a t is \p NULL.
1942 */
1943 int osl_get_num_rows(const struct osl_table *t, unsigned *num_rows)
1944 {
1945 if (!t)
1946 return -E_BAD_TABLE;
1947 assert(t->num_rows >= t->num_invalid_rows);
1948 *num_rows = t->num_rows - t->num_invalid_rows;
1949 return 1;
1950 }
1951
1952 /**
1953 * Get the rank of a row.
1954 *
1955 * \param t An open osl table.
1956 * \param r The row to get the rank of.
1957 * \param col_num The number of an rbtree column.
1958 * \param rank Result pointer.
1959 *
1960 * The rank is, by definition, the position of the row in the linear order
1961 * determined by an in-order tree walk of the rbtree associated with column
1962 * number \a col_num of \a table.
1963 *
1964 * \return Positive on success, negative on errors.
1965 *
1966 * \sa osl_get_nth_row().
1967 */
1968 int osl_get_rank(const struct osl_table *t, struct osl_row *r,
1969 unsigned col_num, unsigned *rank)
1970 {
1971 struct osl_object obj;
1972 struct osl_column *col;
1973 struct rb_node *node;
1974 int ret = check_rbtree_col(t, col_num, &col);
1975
1976 if (ret < 0)
1977 return ret;
1978 ret = osl_get_object(t, r, col_num, &obj);
1979 if (ret < 0)
1980 return ret;
1981 ret = search_rbtree(&obj, t, col_num, &node, NULL);
1982 if (ret < 0)
1983 return ret;
1984 ret = rb_rank(node, rank);
1985 if (ret < 0)
1986 return -E_BAD_ROW;
1987 return 1;
1988 }
1989
1990 /**
1991 * Get the row with n-th greatest value.
1992 *
1993 * \param t Pointer to an open osl table.
1994 * \param col_num The column number.
1995 * \param n The rank of the desired row.
1996 * \param result Row is returned here.
1997 *
1998 * Retrieve the n-th order statistic with respect to the compare function
1999 * of the rbtree column \a col_num. In other words, get that row with
2000 * \a n th greatest value in column \a col_num. It's an error if
2001 * \a col_num is not a rbtree column, or if \a n is larger than the
2002 * number of rows in the table.
2003 *
2004 * \return Positive on success, negative on errors. Possible errors:
2005 * \p E_BAD_TABLE, \p E_BAD_STORAGE_FLAGS, \p E_RB_KEY_NOT_FOUND.
2006 *
2007 * \sa osl_storage_flags, osl_compare_func, osl_get_row(),
2008 * osl_rbtree_last_row(), osl_rbtree_first_row(), osl_get_rank().
2009 */
2010 int osl_get_nth_row(const struct osl_table *t, unsigned col_num,
2011 unsigned n, struct osl_row **result)
2012 {
2013 struct osl_column *col;
2014 struct rb_node *node;
2015 unsigned num_rows;
2016 int ret;
2017
2018 if (n == 0)
2019 return -E_RB_KEY_NOT_FOUND;
2020 ret = osl_get_num_rows(t, &num_rows);
2021 if (ret < 0)
2022 return ret;
2023 if (n > num_rows)
2024 return -E_RB_KEY_NOT_FOUND;
2025 ret = check_rbtree_col(t, col_num, &col);
2026 if (ret < 0)
2027 return ret;
2028 node = rb_nth(col->rbtree.rb_node, n);
2029 if (!node)
2030 return -E_RB_KEY_NOT_FOUND;
2031 *result = get_row_pointer(node, col->rbtree_num);
2032 return 1;
2033 }
2034
2035 /**
2036 * Get the row corresponding to the smallest rbtree node of a column.
2037 *
2038 * \param t An open rbtree table.
2039 * \param col_num The number of the rbtree column.
2040 * \param result A pointer to the first row is returned here.
2041 *
2042 * The rbtree node of the smallest object (with respect to the corresponding
2043 * compare function) is selected and the row containing this object is
2044 * returned. It is an error if \a col_num refers to a column without an
2045 * associated rbtree.
2046 *
2047 * \return Positive on success, negative on errors.
2048 *
2049 * \sa osl_get_nth_row(), osl_rbtree_last_row().
2050 */
2051 int osl_rbtree_first_row(const struct osl_table *t, unsigned col_num,
2052 struct osl_row **result)
2053 {
2054 return osl_get_nth_row(t, col_num, 1, result);
2055 }
2056
2057 /**
2058 * Get the row corresponding to the greatest rbtree node of a column.
2059 *
2060 * \param t The same meaning as in \p osl_rbtree_first_row().
2061 * \param col_num The same meaning as in \p osl_rbtree_first_row().
2062 * \param result The same meaning as in \p osl_rbtree_first_row().
2063 *
2064 * This function works just like osl_rbtree_first_row(), the only difference
2065 * is that the row containing the greatest rather than the smallest object is
2066 * returned.
2067 *
2068 * \return Positive on success, negative on errors.
2069 *
2070 * \sa osl_get_nth_row(), osl_rbtree_first_row().
2071 */
2072 int osl_rbtree_last_row(const struct osl_table *t, unsigned col_num,
2073 struct osl_row **result)
2074 {
2075 unsigned num_rows;
2076 int ret = osl_get_num_rows(t, &num_rows);
2077
2078 if (ret < 0)
2079 return ret;
2080 return osl_get_nth_row(t, col_num, num_rows, result);
2081 }