Implement afs events.
[paraslash.git] / osl.c
1 /*
2 * Copyright (C) 2007 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file osl.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 * Map a file into memory.
161 *
162 * \param path Name of the regular file to map.
163 * \param open_mode Either \p O_RDONLY or \p O_RDWR.
164 * \param obj On success, the mapping is returned here.
165 *
166 * \return Positive on success, negative on errors. Possible errors include: \p
167 * E_FSTAT, any errors returned by para_open(), \p E_EMPTY, \p E_MMAP.
168 *
169 * \sa para_open(), mmap(2).
170 */
171 int mmap_full_file(const char *path, int open_mode, struct osl_object *obj)
172 {
173 int fd, ret, mmap_prot, mmap_flags;
174 struct stat file_status;
175
176 if (open_mode == O_RDONLY) {
177 mmap_prot = PROT_READ;
178 mmap_flags = MAP_PRIVATE;
179 } else {
180 mmap_prot = PROT_READ | PROT_WRITE;
181 mmap_flags = MAP_SHARED;
182 }
183 ret = para_open(path, open_mode, 0);
184 if (ret < 0)
185 return ret;
186 fd = ret;
187 ret = -E_FSTAT;
188 if (fstat(fd, &file_status) < 0)
189 goto out;
190 obj->size = file_status.st_size;
191 ret = -E_EMPTY;
192 PARA_DEBUG_LOG("%s: size %zu\n", path, obj->size);
193 if (!obj->size)
194 goto out;
195 obj->data = mmap(NULL, obj->size, mmap_prot, mmap_flags, fd, 0);
196 if (obj->data == MAP_FAILED) {
197 obj->data = NULL;
198 ret = -E_MMAP;
199 goto out;
200 }
201 ret = 1;
202 out:
203 close(fd);
204 return ret;
205 }
206
207 /**
208 * Traverse the given directory recursively.
209 *
210 * \param dirname The directory to traverse.
211 * \param func The function to call for each entry.
212 * \param private_data Pointer to an arbitrary data structure.
213 *
214 * For each regular file under \a dirname, the supplied function \a func is
215 * called. The full path of the regular file and the \a private_data pointer
216 * are passed to \a func. Directories for which the calling process has no
217 * permissions to change to are silently ignored.
218 *
219 * \return On success, 1 is returned. Otherwise, this function returns a
220 * negative value which indicates the kind of the error.
221 */
222 int for_each_file_in_dir(const char *dirname,
223 int (*func)(const char *, const void *), const void *private_data)
224 {
225 DIR *dir;
226 struct dirent *entry;
227 int cwd_fd, ret2, ret = para_opendir(dirname, &dir, &cwd_fd);
228
229 if (ret < 0)
230 return ret == -E_CHDIR_PERM? 1 : ret;
231 /* scan cwd recursively */
232 while ((entry = readdir(dir))) {
233 mode_t m;
234 char *tmp;
235 struct stat s;
236
237 if (!strcmp(entry->d_name, "."))
238 continue;
239 if (!strcmp(entry->d_name, ".."))
240 continue;
241 if (lstat(entry->d_name, &s) == -1)
242 continue;
243 m = s.st_mode;
244 if (!S_ISREG(m) && !S_ISDIR(m))
245 continue;
246 tmp = make_message("%s/%s", dirname, entry->d_name);
247 if (!S_ISDIR(m)) {
248 ret = func(tmp, private_data);
249 free(tmp);
250 if (ret < 0)
251 goto out;
252 continue;
253 }
254 /* directory */
255 ret = for_each_file_in_dir(tmp, func, private_data);
256 free(tmp);
257 if (ret < 0)
258 goto out;
259 }
260 ret = 1;
261 out:
262 closedir(dir);
263 ret2 = para_fchdir(cwd_fd);
264 if (ret2 < 0 && ret >= 0)
265 ret = ret2;
266 close(cwd_fd);
267 return ret;
268 }
269
270 static int verify_name(const char *name)
271 {
272 if (!name)
273 return -E_BAD_NAME;
274 if (!*name)
275 return -E_BAD_NAME;
276 if (strchr(name, '/'))
277 return -E_BAD_NAME;
278 if (!strcmp(name, ".."))
279 return -E_BAD_NAME;
280 if (!strcmp(name, "."))
281 return -E_BAD_NAME;
282 return 1;
283 }
284
285 /**
286 * Compare two osl objects pointing to unsigned integers of 32 bit size.
287 *
288 * \param obj1 Pointer to the first integer.
289 * \param obj2 Pointer to the second integer.
290 *
291 * \return The values required for an osl compare function.
292 *
293 * \sa osl_compare_func, osl_hash_compare().
294 */
295 int uint32_compare(const struct osl_object *obj1, const struct osl_object *obj2)
296 {
297 uint32_t d1 = read_u32((const char *)obj1->data);
298 uint32_t d2 = read_u32((const char *)obj2->data);
299
300 if (d1 < d2)
301 return 1;
302 if (d1 > d2)
303 return -1;
304 return 0;
305 }
306
307 /**
308 * Compare two osl objects pointing to hash values.
309 *
310 * \param obj1 Pointer to the first hash object.
311 * \param obj2 Pointer to the second hash object.
312 *
313 * \return The values required for an osl compare function.
314 *
315 * \sa osl_compare_func, uint32_compare().
316 */
317 int osl_hash_compare(const struct osl_object *obj1, const struct osl_object *obj2)
318 {
319 return hash_compare((HASH_TYPE *)obj1->data, (HASH_TYPE *)obj2->data);
320 }
321
322 static char *disk_storage_dirname(const struct osl_table *t, unsigned col_num,
323 const char *ds_name)
324 {
325 char *dirname, *column_name = column_filename(t, col_num);
326
327 if (!(t->desc->flags & OSL_LARGE_TABLE))
328 return column_name;
329 dirname = make_message("%s/%.2s", column_name, ds_name);
330 free(column_name);
331 return dirname;
332 }
333
334 static char *disk_storage_name_of_object(const struct osl_table *t,
335 const struct osl_object *obj)
336 {
337 HASH_TYPE hash[HASH_SIZE];
338 hash_object(obj, hash);
339 return disk_storage_name_of_hash(t, hash);
340 }
341
342 static int disk_storage_name_of_row(const struct osl_table *t,
343 const struct osl_row *row, char **name)
344 {
345 struct osl_object obj;
346 int ret = osl_get_object(t, row, t->disk_storage_name_column, &obj);
347
348 if (ret < 0)
349 return ret;
350 *name = disk_storage_name_of_object(t, &obj);
351 return 1;
352 }
353
354 static void column_name_hash(const char *col_name, HASH_TYPE *hash)
355 {
356 return hash_function(col_name, strlen(col_name), hash);
357 }
358
359 static int init_column_descriptions(struct osl_table *t)
360 {
361 int i, j, ret;
362 const struct osl_column_description *cd;
363
364 ret = -E_BAD_TABLE_DESC;
365 ret = verify_name(t->desc->name);
366 if (ret < 0)
367 goto err;
368 ret = -E_BAD_DB_DIR;
369 if (!t->desc->dir && (t->num_disk_storage_columns || t->num_mapped_columns))
370 goto err;
371 /* the size of the index header without column descriptions */
372 t->index_header_size = IDX_COLUMN_DESCRIPTIONS;
373 FOR_EACH_COLUMN(i, t->desc, cd) {
374 struct osl_column *col = t->columns + i;
375 if (cd->storage_flags & OSL_RBTREE) {
376 if (!cd->compare_function)
377 return -E_NO_COMPARE_FUNC;
378 }
379 if (cd->storage_type == OSL_NO_STORAGE)
380 continue;
381 ret = -E_NO_COLUMN_NAME;
382 if (!cd->name || !cd->name[0])
383 goto err;
384 ret = verify_name(cd->name);
385 if (ret < 0)
386 goto err;
387 t->index_header_size += index_column_description_size(cd->name);
388 column_name_hash(cd->name, col->name_hash);
389 ret = -E_DUPLICATE_COL_NAME;
390 for (j = i + 1; j < t->desc->num_columns; j++) {
391 const char *name2 = get_column_description(t->desc,
392 j)->name;
393 if (cd->name && name2 && !strcmp(cd->name, name2))
394 goto err;
395 }
396 }
397 return 1;
398 err:
399 return ret;
400 }
401
402 /**
403 * Initialize a struct table from given table description.
404 *
405 * \param desc The description of the osl table.
406 * \param table_ptr Result is returned here.
407 *
408 * This function performs several sanity checks on \p desc and returns if any
409 * of these tests fail. On success, a struct \p osl_table is allocated and
410 * initialized with data derived from \p desc.
411 *
412 * \return Positive on success, negative on errors. Possible errors include: \p
413 * E_BAD_TABLE_DESC, \p E_NO_COLUMN_DESC, \p E_NO_COLUMNS, \p
414 * E_BAD_STORAGE_TYPE, \p E_BAD_STORAGE_FLAGS, \p E_BAD_STORAGE_SIZE, \p
415 * E_NO_UNIQUE_RBTREE_COLUMN, \p E_NO_RBTREE_COL.
416 *
417 * \sa struct osl_table.
418 */
419 int init_table_structure(const struct osl_table_description *desc,
420 struct osl_table **table_ptr)
421 {
422 const struct osl_column_description *cd;
423 struct osl_table *t = para_calloc(sizeof(*t));
424 int i, ret = -E_BAD_TABLE_DESC, have_disk_storage_name_column = 0;
425
426 if (!desc)
427 goto err;
428 PARA_DEBUG_LOG("creating table structure for '%s' from table "
429 "description\n", desc->name);
430 ret = -E_NO_COLUMN_DESC;
431 if (!desc->column_descriptions)
432 goto err;
433 ret = -E_NO_COLUMNS;
434 if (!desc->num_columns)
435 goto err;
436 t->columns = para_calloc(desc->num_columns * sizeof(struct osl_column));
437 t->desc = desc;
438 FOR_EACH_COLUMN(i, t->desc, cd) {
439 enum osl_storage_type st = cd->storage_type;
440 enum osl_storage_flags sf = cd->storage_flags;
441 struct osl_column *col = &t->columns[i];
442
443 ret = -E_BAD_STORAGE_TYPE;
444 if (st != OSL_MAPPED_STORAGE && st != OSL_DISK_STORAGE
445 && st != OSL_NO_STORAGE)
446 goto err;
447 ret = -E_BAD_STORAGE_FLAGS;
448 if (st == OSL_DISK_STORAGE && sf & OSL_RBTREE)
449 goto err;
450 ret = -E_BAD_STORAGE_SIZE;
451 if (sf & OSL_FIXED_SIZE && !cd->data_size)
452 goto err;
453 switch (st) {
454 case OSL_DISK_STORAGE:
455 t->num_disk_storage_columns++;
456 break;
457 case OSL_MAPPED_STORAGE:
458 t->num_mapped_columns++;
459 col->index_offset = t->row_index_size;
460 t->row_index_size += 8;
461 break;
462 case OSL_NO_STORAGE:
463 col->volatile_num = t->num_volatile_columns;
464 t->num_volatile_columns++;
465 break;
466 }
467 if (sf & OSL_RBTREE) {
468 col->rbtree_num = t->num_rbtrees;
469 t->num_rbtrees++;
470 if ((sf & OSL_UNIQUE) && (st == OSL_MAPPED_STORAGE)) {
471 if (!have_disk_storage_name_column)
472 t->disk_storage_name_column = i;
473 have_disk_storage_name_column = 1;
474 }
475 }
476 }
477 ret = -E_NO_UNIQUE_RBTREE_COLUMN;
478 if (t->num_disk_storage_columns && !have_disk_storage_name_column)
479 goto err;
480 ret = -E_NO_RBTREE_COL;
481 if (!t->num_rbtrees)
482 goto err;
483 /* success */
484 PARA_DEBUG_LOG("OK. Index entry size: %u\n", t->row_index_size);
485 ret = init_column_descriptions(t);
486 if (ret < 0)
487 goto err;
488 *table_ptr = t;
489 return 1;
490 err:
491 free(t->columns);
492 free(t);
493 return ret;
494 }
495
496 /**
497 * Read the table description from index header.
498 *
499 * \param map The memory mapping of the index file.
500 * \param desc The values found in the index header are returned here.
501 *
502 * Read the index header, check for the paraslash magic string and the table version number.
503 * Read all information stored in the index header into \a desc.
504 *
505 * \return Positive on success, negative on errors.
506 *
507 * \sa struct osl_table_description, osl_create_table.
508 */
509 int read_table_desc(struct osl_object *map, struct osl_table_description *desc)
510 {
511 char *buf = map->data;
512 uint8_t version;
513 uint16_t header_size;
514 int ret, i;
515 unsigned offset;
516 struct osl_column_description *cd;
517
518 if (map->size < MIN_INDEX_HEADER_SIZE(1))
519 return -E_SHORT_TABLE;
520 if (strncmp(buf + IDX_PARA_MAGIC, PARA_MAGIC, strlen(PARA_MAGIC)))
521 return -E_NO_MAGIC;
522 version = read_u8(buf + IDX_VERSION);
523 if (version < MIN_TABLE_VERSION || version > MAX_TABLE_VERSION)
524 return -E_VERSION_MISMATCH;
525 desc->num_columns = read_u8(buf + IDX_TABLE_FLAGS);
526 desc->flags = read_u8(buf + IDX_TABLE_FLAGS);
527 desc->num_columns = read_u16(buf + IDX_NUM_COLUMNS);
528 PARA_DEBUG_LOG("%u columns\n", desc->num_columns);
529 if (!desc->num_columns)
530 return -E_NO_COLUMNS;
531 header_size = read_u16(buf + IDX_HEADER_SIZE);
532 if (map->size < header_size)
533 return -E_BAD_SIZE;
534 desc->column_descriptions = para_calloc(desc->num_columns
535 * sizeof(struct osl_column_description));
536 offset = IDX_COLUMN_DESCRIPTIONS;
537 FOR_EACH_COLUMN(i, desc, cd) {
538 char *null_byte;
539
540 ret = -E_SHORT_TABLE;
541 if (map->size < offset + MIN_IDX_COLUMN_DESCRIPTION_SIZE) {
542 PARA_ERROR_LOG("map size = %zu < %u = offset + min desc size\n",
543 map->size, offset + MIN_IDX_COLUMN_DESCRIPTION_SIZE);
544 goto err;
545 }
546 cd->storage_type = read_u16(buf + offset + IDX_CD_STORAGE_TYPE);
547 cd->storage_flags = read_u16(buf + offset +
548 IDX_CD_STORAGE_FLAGS);
549 cd->data_size = read_u32(buf + offset + IDX_CD_DATA_SIZE);
550 null_byte = memchr(buf + offset + IDX_CD_NAME, '\0',
551 map->size - offset - IDX_CD_NAME);
552 ret = -E_INDEX_CORRUPTION;
553 if (!null_byte)
554 goto err;
555 cd->name = para_strdup(buf + offset + IDX_CD_NAME);
556 offset += index_column_description_size(cd->name);
557 }
558 if (offset != header_size) {
559 ret = -E_INDEX_CORRUPTION;
560 PARA_ERROR_LOG("real header size = %u != %u = stored header size\n",
561 offset, header_size);
562 goto err;
563 }
564 return 1;
565 err:
566 FOR_EACH_COLUMN(i, desc, cd)
567 free(cd->name);
568 return ret;
569 }
570
571 /*
572 * check whether the table description given by \p t->desc matches the on-disk
573 * table structure stored in the index of \a t.
574 */
575 static int compare_table_descriptions(struct osl_table *t)
576 {
577 int i, ret;
578 struct osl_table_description desc;
579 const struct osl_column_description *cd1, *cd2;
580
581 /* read the on-disk structure into desc */
582 ret = read_table_desc(&t->index_map, &desc);
583 if (ret < 0)
584 return ret;
585 ret = -E_BAD_TABLE_FLAGS;
586 if (desc.flags != t->desc->flags)
587 goto out;
588 ret = -E_BAD_COLUMN_NUM;
589 if (desc.num_columns != t->desc->num_columns)
590 goto out;
591 FOR_EACH_COLUMN(i, t->desc, cd1) {
592 cd2 = get_column_description(&desc, i);
593 ret = -E_BAD_STORAGE_TYPE;
594 if (cd1->storage_type != cd2->storage_type)
595 goto out;
596 ret = -E_BAD_STORAGE_FLAGS;
597 if (cd1->storage_flags != cd2->storage_flags) {
598 PARA_ERROR_LOG("sf1 = %u != %u = sf2\n",
599 cd1->storage_flags, cd2->storage_flags);
600 goto out;
601 }
602 ret = -E_BAD_DATA_SIZE;
603 if (cd1->storage_flags & OSL_FIXED_SIZE)
604 if (cd1->data_size != cd2->data_size)
605 goto out;
606 ret = -E_BAD_COLUMN_NAME;
607 if (strcmp(cd1->name, cd2->name))
608 goto out;
609 }
610 PARA_DEBUG_LOG("table description of '%s' matches on-disk data, good\n",
611 t->desc->name);
612 ret = 1;
613 out:
614 FOR_EACH_COLUMN(i, &desc, cd1)
615 free(cd1->name);
616 free(desc.column_descriptions);
617 return ret;
618 }
619
620 static int create_table_index(struct osl_table *t)
621 {
622 char *buf, *filename;
623 int i, ret;
624 size_t size = t->index_header_size;
625 const struct osl_column_description *cd;
626 unsigned offset;
627
628 PARA_INFO_LOG("creating %zu byte index for table %s\n", size,
629 t->desc->name);
630 buf = para_calloc(size);
631 sprintf(buf + IDX_PARA_MAGIC, "%s", PARA_MAGIC);
632 write_u8(buf + IDX_TABLE_FLAGS, t->desc->flags);
633 write_u8(buf + IDX_DIRTY_FLAG, 0);
634 write_u8(buf + IDX_VERSION, CURRENT_TABLE_VERSION);
635 write_u16(buf + IDX_NUM_COLUMNS, t->desc->num_columns);
636 write_u16(buf + IDX_HEADER_SIZE, t->index_header_size);
637 offset = IDX_COLUMN_DESCRIPTIONS;
638 FOR_EACH_COLUMN(i, t->desc, cd) {
639 write_u16(buf + offset + IDX_CD_STORAGE_TYPE,
640 cd->storage_type);
641 write_u16(buf + offset + IDX_CD_STORAGE_FLAGS,
642 cd->storage_flags);
643 if (cd->storage_flags & OSL_FIXED_SIZE)
644 write_u32(buf + offset + IDX_CD_DATA_SIZE,
645 cd->data_size);
646 strcpy(buf + offset + IDX_CD_NAME, cd->name);
647 offset += index_column_description_size(cd->name);
648 }
649 assert(offset = size);
650 filename = index_filename(t->desc);
651 ret = para_write_file(filename, buf, size);
652 free(buf);
653 free(filename);
654 return ret;
655 }
656
657 /**
658 * Create a new osl table.
659 *
660 * \param desc Pointer to the table description.
661 *
662 * \return Standard.
663 */
664 int osl_create_table(const struct osl_table_description *desc)
665 {
666 const struct osl_column_description *cd;
667 char *table_dir = NULL, *filename;
668 struct osl_table *t;
669 int i, ret = init_table_structure(desc, &t);
670
671 if (ret < 0)
672 return ret;
673 PARA_INFO_LOG("creating %s\n", desc->name);
674 FOR_EACH_COLUMN(i, t->desc, cd) {
675 if (cd->storage_type == OSL_NO_STORAGE)
676 continue;
677 if (!table_dir) {
678 ret = para_mkdir(desc->dir, 0777);
679 if (ret < 0 && !is_errno(-ret, EEXIST))
680 goto out;
681 table_dir = make_message("%s/%s", desc->dir,
682 desc->name);
683 ret = para_mkdir(table_dir, 0777);
684 if (ret < 0)
685 goto out;
686 }
687 filename = column_filename(t, i);
688 PARA_INFO_LOG("filename: %s\n", filename);
689 if (cd->storage_type == OSL_MAPPED_STORAGE) {
690 ret = para_open(filename, O_RDWR | O_CREAT | O_EXCL,
691 0644);
692 free(filename);
693 if (ret < 0)
694 goto out;
695 close(ret);
696 continue;
697 }
698 /* DISK STORAGE */
699 ret = para_mkdir(filename, 0777);
700 free(filename);
701 if (ret < 0)
702 goto out;
703 }
704 if (t->num_mapped_columns) {
705 ret = create_table_index(t);
706 if (ret < 0)
707 goto out;
708 }
709 ret = 1;
710 out:
711 free(table_dir);
712 free(t->columns);
713 free(t);
714 return ret;
715 }
716
717 static int table_is_dirty(struct osl_table *t)
718 {
719 char *buf = (char *)t->index_map.data + IDX_DIRTY_FLAG;
720 uint8_t dirty = read_u8(buf) & 0x1;
721 return !!dirty;
722 }
723
724 static void mark_table_dirty(struct osl_table *t)
725 {
726 char *buf = (char *)t->index_map.data + IDX_DIRTY_FLAG;
727 write_u8(buf, read_u8(buf) | 1);
728 }
729
730 static void mark_table_clean(struct osl_table *t)
731 {
732 char *buf = (char *)t->index_map.data + IDX_DIRTY_FLAG;
733 write_u8(buf, read_u8(buf) & 0xfe);
734 }
735
736 static void unmap_column(struct osl_table *t, unsigned col_num)
737 {
738 struct osl_object map = t->columns[col_num].data_map;
739 int ret;
740 if (!map.data)
741 return;
742 ret = para_munmap(map.data, map.size);
743 assert(ret > 0);
744 map.data = NULL;
745 }
746
747 /**
748 * Unmap all mapped files of an osl table.
749 *
750 * \param t Pointer to a mapped table.
751 * \param flags Options for unmapping.
752 *
753 * \return Positive on success, negative on errors.
754 *
755 * \sa map_table(), enum osl_close_flags, para_munmap().
756 */
757 int unmap_table(struct osl_table *t, enum osl_close_flags flags)
758 {
759 unsigned i;
760 const struct osl_column_description *cd;
761 int ret;
762
763 if (!t->num_mapped_columns) /* can this ever happen? */
764 return 1;
765 PARA_DEBUG_LOG("unmapping table '%s'\n", t->desc->name);
766 if (!t->index_map.data)
767 return -E_NOT_MAPPED;
768 if (flags & OSL_MARK_CLEAN)
769 mark_table_clean(t);
770 ret = para_munmap(t->index_map.data, t->index_map.size);
771 if (ret < 0)
772 return ret;
773 t->index_map.data = NULL;
774 if (!t->num_rows)
775 return 1;
776 FOR_EACH_MAPPED_COLUMN(i, t, cd)
777 unmap_column(t, i);
778 return 1;
779 }
780
781 static int map_column(struct osl_table *t, unsigned col_num)
782 {
783 struct stat statbuf;
784 char *filename = column_filename(t, col_num);
785 int ret = -E_STAT;
786 if (stat(filename, &statbuf) < 0) {
787 free(filename);
788 return ret;
789 }
790 if (!(S_IFREG & statbuf.st_mode)) {
791 free(filename);
792 return ret;
793 }
794 ret = mmap_full_file(filename, O_RDWR,
795 &t->columns[col_num].data_map);
796 free(filename);
797 return ret;
798 }
799
800 /**
801 * Map the index file and all columns of type \p OSL_MAPPED_STORAGE into memory.
802 *
803 * \param t Pointer to an initialized table structure.
804 * \param flags Mapping options.
805 *
806 * \return Negative return value on errors; on success the number of rows
807 * (including invalid rows) is returned.
808 *
809 * \sa unmap_table(), enum map_table_flags, osl_open_table(), mmap(2).
810 */
811 int map_table(struct osl_table *t, enum map_table_flags flags)
812 {
813 char *filename;
814 const struct osl_column_description *cd;
815 int i = 0, ret, num_rows = 0;
816
817 if (!t->num_mapped_columns)
818 return 0;
819 if (t->index_map.data)
820 return -E_ALREADY_MAPPED;
821 filename = index_filename(t->desc);
822 PARA_DEBUG_LOG("mapping table '%s' (index: %s)\n", t->desc->name, filename);
823 ret = mmap_full_file(filename, flags & MAP_TBL_FL_MAP_RDONLY?
824 O_RDONLY : O_RDWR, &t->index_map);
825 free(filename);
826 if (ret < 0)
827 return ret;
828 if (flags & MAP_TBL_FL_VERIFY_INDEX) {
829 ret = compare_table_descriptions(t);
830 if (ret < 0)
831 goto err;
832 }
833 ret = -E_BUSY;
834 if (!(flags & MAP_TBL_FL_IGNORE_DIRTY)) {
835 if (table_is_dirty(t)) {
836 PARA_ERROR_LOG("%s is dirty\n", t->desc->name);
837 goto err;
838 }
839 }
840 mark_table_dirty(t);
841 num_rows = table_num_rows(t);
842 if (!num_rows)
843 return num_rows;
844 /* map data files */
845 FOR_EACH_MAPPED_COLUMN(i, t, cd) {
846 ret = map_column(t, i);
847 if (ret < 0)
848 goto err;
849 }
850 return num_rows;
851 err: /* unmap what is already mapped */
852 for (i--; i >= 0; i--) {
853 struct osl_object map = t->columns[i].data_map;
854 para_munmap(map.data, map.size);
855 map.data = NULL;
856 }
857 para_munmap(t->index_map.data, t->index_map.size);
858 t->index_map.data = NULL;
859 return ret;
860 }
861
862 /**
863 * Retrieve a mapped object by row and column number.
864 *
865 * \param t Pointer to an open osl table.
866 * \param col_num Number of the mapped column containing the object to retrieve.
867 * \param row_num Number of the row containing the object to retrieve.
868 * \param obj The result is returned here.
869 *
870 * It is considered an error if \a col_num does not refer to a column
871 * of storage type \p OSL_MAPPED_STORAGE.
872 *
873 * \return Positive on success, negative on errors. Possible errors include:
874 * \p E_BAD_ROW_NUM, \p E_INVALID_OBJECT.
875 *
876 * \sa osl_storage_type.
877 */
878 int get_mapped_object(const struct osl_table *t, unsigned col_num,
879 uint32_t row_num, struct osl_object *obj)
880 {
881 struct osl_column *col = &t->columns[col_num];
882 uint32_t offset;
883 char *header;
884 char *cell_index;
885 int ret;
886
887 if (t->num_rows <= row_num)
888 return -E_BAD_ROW_NUM;
889 ret = get_cell_index(t, row_num, col_num, &cell_index);
890 if (ret < 0)
891 return ret;
892 offset = read_u32(cell_index);
893 obj->size = read_u32(cell_index + 4) - 1;
894 header = col->data_map.data + offset;
895 obj->data = header + 1;
896 if (read_u8(header) == 0xff) {
897 PARA_ERROR_LOG("col %u, size %zu, offset %u\n", col_num,
898 obj->size, offset);
899 return -E_INVALID_OBJECT;
900 }
901 return 1;
902 }
903
904 static int search_rbtree(const struct osl_object *obj,
905 const struct osl_table *t, unsigned col_num,
906 struct rb_node **result, struct rb_node ***rb_link)
907 {
908 struct osl_column *col = &t->columns[col_num];
909 struct rb_node **new = &col->rbtree.rb_node, *parent = NULL;
910 const struct osl_column_description *cd =
911 get_column_description(t->desc, col_num);
912 enum osl_storage_type st = cd->storage_type;
913 while (*new) {
914 struct osl_row *this_row = get_row_pointer(*new,
915 col->rbtree_num);
916 int ret;
917 struct osl_object this_obj;
918 parent = *new;
919 if (st == OSL_MAPPED_STORAGE) {
920 ret = get_mapped_object(t, col_num, this_row->num,
921 &this_obj);
922 if (ret < 0)
923 return ret;
924 } else
925 this_obj = this_row->volatile_objects[col->volatile_num];
926 ret = cd->compare_function(obj, &this_obj);
927 if (!ret) {
928 if (result)
929 *result = get_rb_node_pointer(this_row,
930 col->rbtree_num);
931 return 1;
932 }
933 if (ret < 0)
934 new = &((*new)->rb_left);
935 else
936 new = &((*new)->rb_right);
937 }
938 if (result)
939 *result = parent;
940 if (rb_link)
941 *rb_link = new;
942 return -E_RB_KEY_NOT_FOUND;
943 }
944
945 static int insert_rbtree(struct osl_table *t, unsigned col_num,
946 const struct osl_row *row, const struct osl_object *obj)
947 {
948 struct rb_node *parent, **rb_link;
949 unsigned rbtree_num;
950 struct rb_node *n;
951 int ret = search_rbtree(obj, t, col_num, &parent, &rb_link);
952
953 if (ret > 0)
954 return -E_RB_KEY_EXISTS;
955 rbtree_num = t->columns[col_num].rbtree_num;
956 n = get_rb_node_pointer(row, rbtree_num);
957 rb_link_node(n, parent, rb_link);
958 rb_insert_color(n, &t->columns[col_num].rbtree);
959 return 1;
960 }
961
962 static void remove_rb_node(struct osl_table *t, unsigned col_num,
963 const struct osl_row *row)
964 {
965 struct osl_column *col = &t->columns[col_num];
966 const struct osl_column_description *cd =
967 get_column_description(t->desc, col_num);
968 enum osl_storage_flags sf = cd->storage_flags;
969 struct rb_node *victim, *splice_out_node, *tmp;
970 if (!(sf & OSL_RBTREE))
971 return;
972 /*
973 * Which node is removed/spliced out actually depends on how many
974 * children the victim node has: If it has no children, it gets
975 * deleted. If it has one child, it gets spliced out. If it has two
976 * children, its successor (which has at most a right child) gets
977 * spliced out.
978 */
979 victim = get_rb_node_pointer(row, col->rbtree_num);
980 if (victim->rb_left && victim->rb_right)
981 splice_out_node = rb_next(victim);
982 else
983 splice_out_node = victim;
984 /* Go up to the root and decrement the size of each node in the path. */
985 for (tmp = splice_out_node; tmp; tmp = rb_parent(tmp))
986 tmp->size--;
987 rb_erase(victim, &col->rbtree);
988 }
989
990 static int add_row_to_rbtrees(struct osl_table *t, uint32_t row_num,
991 struct osl_object *volatile_objs, struct osl_row **row_ptr)
992 {
993 unsigned i;
994 int ret;
995 struct osl_row *row = allocate_row(t->num_rbtrees);
996 const struct osl_column_description *cd;
997
998 row->num = row_num;
999 row->volatile_objects = volatile_objs;
1000 FOR_EACH_RBTREE_COLUMN(i, t, cd) {
1001 if (cd->storage_type == OSL_MAPPED_STORAGE) {
1002 struct osl_object obj;
1003 ret = get_mapped_object(t, i, row_num, &obj);
1004 if (ret < 0)
1005 goto err;
1006 ret = insert_rbtree(t, i, row, &obj);
1007 } else { /* volatile */
1008 const struct osl_object *obj
1009 = volatile_objs + t->columns[i].volatile_num;
1010 ret = insert_rbtree(t, i, row, obj);
1011 }
1012 if (ret < 0)
1013 goto err;
1014 }
1015 if (row_ptr)
1016 *row_ptr = row;
1017 return 1;
1018 err: /* rollback changes, i.e. remove added entries from rbtrees */
1019 while (i)
1020 remove_rb_node(t, i--, row);
1021 free(row);
1022 return ret;
1023 }
1024
1025 static void free_volatile_objects(const struct osl_table *t,
1026 enum osl_close_flags flags)
1027 {
1028 int i, j;
1029 struct rb_node *n;
1030 struct osl_column *rb_col;
1031 const struct osl_column_description *cd;
1032
1033 if (!t->num_volatile_columns)
1034 return;
1035 /* find the first rbtree column (any will do) */
1036 FOR_EACH_RBTREE_COLUMN(i, t, cd)
1037 break;
1038 rb_col = t->columns + i;
1039 /* walk that rbtree and free all volatile objects */
1040 for (n = rb_first(&rb_col->rbtree); n; n = rb_next(n)) {
1041 struct osl_row *r = get_row_pointer(n, rb_col->rbtree_num);
1042 if (flags & OSL_FREE_VOLATILE)
1043 for (j = 0; j < t->num_volatile_columns; j++)
1044 free(r->volatile_objects[j].data);
1045 free(r->volatile_objects);
1046 }
1047 }
1048
1049 /**
1050 * Erase all rbtree nodes and free resources.
1051 *
1052 * \param t Pointer to an open osl table.
1053 *
1054 * This function is called by osl_close_table().
1055 */
1056 void clear_rbtrees(struct osl_table *t)
1057 {
1058 const struct osl_column_description *cd;
1059 unsigned i, rbtrees_cleared = 0;
1060
1061 FOR_EACH_RBTREE_COLUMN(i, t, cd) {
1062 struct osl_column *col = &t->columns[i];
1063 struct rb_node *n;
1064 rbtrees_cleared++;
1065 for (n = rb_first(&col->rbtree); n;) {
1066 struct osl_row *r;
1067 rb_erase(n, &col->rbtree);
1068 if (rbtrees_cleared == t->num_rbtrees) {
1069 r = get_row_pointer(n, col->rbtree_num);
1070 n = rb_next(n);
1071 free(r);
1072 } else
1073 n = rb_next(n);
1074 }
1075 }
1076
1077 }
1078
1079 /**
1080 * Close an osl table.
1081 *
1082 * \param t Pointer to the table to be closed.
1083 * \param flags Options for what should be cleaned up.
1084 *
1085 * If osl_open_table() succeeds, the resulting table pointer must later be
1086 * passed to this function in order to flush all changes to the file system and
1087 * to free the resources that were allocated by osl_open_table().
1088 *
1089 * \return Positive on success, negative on errors. Possible errors: \p E_BAD_TABLE,
1090 * errors returned by unmap_table().
1091 *
1092 * \sa osl_open_table(), unmap_table().
1093 */
1094 int osl_close_table(struct osl_table *t, enum osl_close_flags flags)
1095 {
1096 int ret;
1097
1098 if (!t)
1099 return -E_BAD_TABLE;
1100 free_volatile_objects(t, flags);
1101 clear_rbtrees(t);
1102 ret = unmap_table(t, flags);
1103 if (ret < 0)
1104 PARA_ERROR_LOG("unmap_table failed: %d\n", ret);
1105 free(t->columns);
1106 free(t);
1107 return ret;
1108 }
1109
1110 /**
1111 * Find out whether the given row number corresponds to an invalid row.
1112 *
1113 * \param t Pointer to the osl table.
1114 * \param row_num The number of the row in question.
1115 *
1116 * By definition, a row is considered invalid if all its index entries
1117 * are invalid.
1118 *
1119 * \return Positive if \a row_num corresponds to an invalid row,
1120 * zero if it corresponds to a valid row, negative on errors.
1121 */
1122 int row_is_invalid(struct osl_table *t, uint32_t row_num)
1123 {
1124 char *row_index;
1125 int i, ret = get_row_index(t, row_num, &row_index);
1126
1127 if (ret < 0)
1128 return ret;
1129 for (i = 0; i < t->row_index_size; i++) {
1130 if ((unsigned char)row_index[i] != 0xff)
1131 return 0;
1132 }
1133 PARA_INFO_LOG("row %d is invalid\n", row_num);
1134 return 1;
1135 }
1136
1137 /**
1138 * Invalidate a row of an osl table.
1139 *
1140 * \param t Pointer to an open osl table.
1141 * \param row_num Number of the row to mark as invalid.
1142 *
1143 * This function marks each mapped object in the index entry of \a row as
1144 * invalid.
1145 *
1146 * \return Positive on success, negative on errors.
1147 */
1148 int mark_row_invalid(struct osl_table *t, uint32_t row_num)
1149 {
1150 char *row_index;
1151 int ret = get_row_index(t, row_num, &row_index);
1152
1153 if (ret < 0)
1154 return ret;
1155 PARA_INFO_LOG("marking row %d as invalid\n", row_num);
1156 memset(row_index, 0xff, t->row_index_size);
1157 return 1;
1158 }
1159
1160 /**
1161 * Initialize all rbtrees and compute number of invalid rows.
1162 *
1163 * \param t The table containing the rbtrees to be initialized.
1164 *
1165 * \return Positive on success, negative on errors.
1166 */
1167 int init_rbtrees(struct osl_table *t)
1168 {
1169 int i, ret;
1170 const struct osl_column_description *cd;
1171
1172 /* create rbtrees */
1173 FOR_EACH_RBTREE_COLUMN(i, t, cd)
1174 t->columns[i].rbtree = RB_ROOT;
1175 /* add valid rows to rbtrees */
1176 t->num_invalid_rows = 0;
1177 for (i = 0; i < t->num_rows; i++) {
1178 ret = row_is_invalid(t, i);
1179 if (ret < 0)
1180 return ret;
1181 if (ret) {
1182 t->num_invalid_rows++;
1183 continue;
1184 }
1185 ret = add_row_to_rbtrees(t, i, NULL, NULL);
1186 if (ret < 0)
1187 return ret;
1188 }
1189 return 1;
1190 }
1191
1192 /**
1193 * Open an osl table.
1194 *
1195 * Each osl table must be opened before its data can be accessed.
1196 *
1197 * \param table_desc Describes the table to be opened.
1198 * \param result Contains a pointer to the open table on success.
1199 *
1200 * The table description given by \a desc should coincide with the
1201 * description used at creation time.
1202 *
1203 * \return Standard.
1204 */
1205 int osl_open_table(const struct osl_table_description *table_desc,
1206 struct osl_table **result)
1207 {
1208 int i, ret;
1209 struct osl_table *t;
1210 const struct osl_column_description *cd;
1211
1212 PARA_INFO_LOG("opening table %s\n", table_desc->name);
1213 ret = init_table_structure(table_desc, &t);
1214 if (ret < 0)
1215 return ret;
1216 FOR_EACH_DISK_STORAGE_COLUMN(i, t, cd) {
1217 /* check if directory exists */
1218 char *dirname = column_filename(t, i);
1219 struct stat statbuf;
1220 ret = stat(dirname, &statbuf);
1221 free(dirname);
1222 if (ret < 0) {
1223 ret = -ERRNO_TO_PARA_ERROR(errno);
1224 goto err;
1225 }
1226 ret = -ERRNO_TO_PARA_ERROR(ENOTDIR);
1227 if (!S_ISDIR(statbuf.st_mode))
1228 goto err;
1229 }
1230 ret = map_table(t, MAP_TBL_FL_VERIFY_INDEX);
1231 if (ret < 0)
1232 goto err;
1233 t->num_rows = ret;
1234 PARA_DEBUG_LOG("num rows: %d\n", t->num_rows);
1235 ret = init_rbtrees(t);
1236 if (ret < 0) {
1237 osl_close_table(t, OSL_MARK_CLEAN); /* ignore further errors */
1238 return ret;
1239 }
1240 *result = t;
1241 return 1;
1242 err:
1243 free(t->columns);
1244 free(t);
1245 return ret;
1246 }
1247
1248 static int create_disk_storage_object_dir(const struct osl_table *t,
1249 unsigned col_num, const char *ds_name)
1250 {
1251 char *dirname;
1252 int ret;
1253
1254 if (!(t->desc->flags & OSL_LARGE_TABLE))
1255 return 1;
1256 dirname = disk_storage_dirname(t, col_num, ds_name);
1257 ret = para_mkdir(dirname, 0777);
1258 free(dirname);
1259 if (ret < 0 && !is_errno(-ret, EEXIST))
1260 return ret;
1261 return 1;
1262 }
1263
1264 static int write_disk_storage_file(const struct osl_table *t, unsigned col_num,
1265 const struct osl_object *obj, const char *ds_name)
1266 {
1267 int ret;
1268 char *filename;
1269
1270 ret = create_disk_storage_object_dir(t, col_num, ds_name);
1271 if (ret < 0)
1272 return ret;
1273 filename = disk_storage_path(t, col_num, ds_name);
1274 ret = para_write_file(filename, obj->data, obj->size);
1275 free(filename);
1276 return ret;
1277 }
1278
1279 static int append_map_file(const struct osl_table *t, unsigned col_num,
1280 const struct osl_object *obj, uint32_t *new_size)
1281 {
1282 char *filename = column_filename(t, col_num);
1283 int ret;
1284 char header = 0; /* zero means valid object */
1285
1286 // PARA_DEBUG_LOG("appending %zu + 1 byte\n", obj->size);
1287 ret = append_file(filename, &header, 1, obj->data, obj->size,
1288 new_size);
1289 free(filename);
1290 return ret;
1291 }
1292
1293 static int append_row_index(const struct osl_table *t, char *row_index)
1294 {
1295 char *filename;
1296 int ret;
1297
1298 if (!t->num_mapped_columns)
1299 return 1;
1300 filename = index_filename(t->desc);
1301 ret = append_file(filename, NULL, 0, row_index,
1302 t->row_index_size, NULL);
1303 free(filename);
1304 return ret;
1305 }
1306
1307 /**
1308 * A wrapper for truncate(2)
1309 *
1310 * \param path Name of the regular file to truncate
1311 * \param size Number of bytes to \b shave \b off
1312 *
1313 * Truncate the regular file named by \a path by \a size bytes.
1314 *
1315 * \return Positive on success, negative on errors. Possible errors include: \p
1316 * E_STAT, \p E_BAD_SIZE, \p E_TRUNC.
1317 *
1318 * \sa truncate(2)
1319 */
1320 int para_truncate(const char *path, off_t size)
1321 {
1322 int ret;
1323 struct stat statbuf;
1324
1325 ret = -E_STAT;
1326 if (stat(path, &statbuf) < 0)
1327 goto out;
1328 ret = -E_BAD_SIZE;
1329 if (statbuf.st_size < size)
1330 goto out;
1331 ret = -E_TRUNC;
1332 if (truncate(path, statbuf.st_size - size) < 0)
1333 goto out;
1334 ret = 1;
1335 out:
1336 return ret;
1337 }
1338
1339 static int truncate_mapped_file(const struct osl_table *t, unsigned col_num,
1340 off_t size)
1341 {
1342 char *filename = column_filename(t, col_num);
1343 int ret = para_truncate(filename, size);
1344 free(filename);
1345 return ret;
1346 }
1347
1348 static int delete_disk_storage_file(const struct osl_table *t, unsigned col_num,
1349 const char *ds_name)
1350 {
1351 char *dirname, *filename = disk_storage_path(t, col_num, ds_name);
1352 int ret = unlink(filename), err = errno;
1353
1354 free(filename);
1355 if (ret < 0)
1356 return -ERRNO_TO_PARA_ERROR(err);
1357 if (!(t->desc->flags & OSL_LARGE_TABLE))
1358 return 1;
1359 dirname = disk_storage_dirname(t, col_num, ds_name);
1360 rmdir(dirname);
1361 free(dirname);
1362 return 1;
1363 }
1364
1365 /**
1366 * Add a new row to an osl table and retrieve this row.
1367 *
1368 * \param t Pointer to an open osl table.
1369 * \param objects Array of objects to be added.
1370 * \param row Result pointer.
1371 *
1372 * The \a objects parameter must point to an array containing one object per
1373 * column. The order of the objects in the array is given by the table
1374 * description of \a table. Several sanity checks are performed during object
1375 * insertion and the function returns without modifying the table if any of
1376 * these tests fail. In fact, it is atomic in the sense that it either
1377 * succeeds or leaves the table unchanged (i.e. either all or none of the
1378 * objects are added to the table).
1379 *
1380 * It is considered an error if an object is added to a column with associated
1381 * rbtree if this object is equal to an object already contained in that column
1382 * (i.e. the compare function for the column's rbtree returns zero).
1383 *
1384 * Possible errors include: \p E_RB_KEY_EXISTS, \p E_BAD_DATA_SIZE.
1385 *
1386 * \return Positive on success, negative on errors.
1387 *
1388 * \sa struct osl_table_description, osl_compare_func, osl_add_row().
1389 */
1390 int osl_add_and_get_row(struct osl_table *t, struct osl_object *objects,
1391 struct osl_row **row)
1392 {
1393 int i, ret;
1394 char *ds_name = NULL;
1395 struct rb_node **rb_parents = NULL, ***rb_links = NULL;
1396 char *new_row_index = NULL;
1397 struct osl_object *volatile_objs = NULL;
1398 const struct osl_column_description *cd;
1399
1400 if (!t)
1401 return -E_BAD_TABLE;
1402 rb_parents = para_malloc(t->num_rbtrees * sizeof(struct rn_node*));
1403 rb_links = para_malloc(t->num_rbtrees * sizeof(struct rn_node**));
1404 if (t->num_mapped_columns)
1405 new_row_index = para_malloc(t->row_index_size);
1406 /* pass 1: sanity checks */
1407 // PARA_DEBUG_LOG("sanity tests: %p:%p\n", objects[0].data,
1408 // objects[1].data);
1409 FOR_EACH_COLUMN(i, t->desc, cd) {
1410 enum osl_storage_type st = cd->storage_type;
1411 enum osl_storage_flags sf = cd->storage_flags;
1412
1413 // ret = -E_NULL_OBJECT;
1414 // if (!objects[i])
1415 // goto out;
1416 if (st == OSL_DISK_STORAGE)
1417 continue;
1418 if (sf & OSL_RBTREE) {
1419 unsigned rbtree_num = t->columns[i].rbtree_num;
1420 ret = -E_RB_KEY_EXISTS;
1421 // PARA_DEBUG_LOG("checking whether %p exists\n",
1422 // objects[i].data);
1423 if (search_rbtree(objects + i, t, i,
1424 &rb_parents[rbtree_num],
1425 &rb_links[rbtree_num]) > 0)
1426 goto out;
1427 }
1428 if (sf & OSL_FIXED_SIZE) {
1429 // PARA_DEBUG_LOG("fixed size. need: %zu, have: %d\n",
1430 // objects[i].size, cd->data_size);
1431 ret = -E_BAD_DATA_SIZE;
1432 if (objects[i].size != cd->data_size)
1433 goto out;
1434 }
1435 }
1436 if (t->num_disk_storage_columns)
1437 ds_name = disk_storage_name_of_object(t,
1438 &objects[t->disk_storage_name_column]);
1439 ret = unmap_table(t, OSL_MARK_CLEAN);
1440 if (ret < 0)
1441 goto out;
1442 // PARA_DEBUG_LOG("sanity tests passed%s\n", "");
1443 /* pass 2: create data files, append map data */
1444 FOR_EACH_COLUMN(i, t->desc, cd) {
1445 enum osl_storage_type st = cd->storage_type;
1446 if (st == OSL_NO_STORAGE)
1447 continue;
1448 if (st == OSL_MAPPED_STORAGE) {
1449 uint32_t new_size;
1450 struct osl_column *col = &t->columns[i];
1451 // PARA_DEBUG_LOG("appending object of size %zu\n",
1452 // objects[i].size);
1453 ret = append_map_file(t, i, objects + i, &new_size);
1454 if (ret < 0)
1455 goto rollback;
1456 update_cell_index(new_row_index, col, new_size,
1457 objects[i].size);
1458 continue;
1459 }
1460 /* DISK_STORAGE */
1461 ret = write_disk_storage_file(t, i, objects + i, ds_name);
1462 if (ret < 0)
1463 goto rollback;
1464 }
1465 ret = append_row_index(t, new_row_index);
1466 if (ret < 0)
1467 goto rollback;
1468 ret = map_table(t, MAP_TBL_FL_VERIFY_INDEX);
1469 if (ret < 0) { /* truncate index and rollback changes */
1470 char *filename = index_filename(t->desc);
1471 para_truncate(filename, t->row_index_size);
1472 free(filename);
1473 goto rollback;
1474 }
1475 /* pass 3: add entry to rbtrees */
1476 if (t->num_volatile_columns) {
1477 volatile_objs = para_calloc(t->num_volatile_columns
1478 * sizeof(struct osl_object));
1479 FOR_EACH_VOLATILE_COLUMN(i, t, cd)
1480 volatile_objs[t->columns[i].volatile_num] = objects[i];
1481 }
1482 t->num_rows++;
1483 // PARA_DEBUG_LOG("adding new entry as row #%d\n", t->num_rows - 1);
1484 ret = add_row_to_rbtrees(t, t->num_rows - 1, volatile_objs, row);
1485 if (ret < 0)
1486 goto out;
1487 // PARA_DEBUG_LOG("added new entry as row #%d\n", t->num_rows - 1);
1488 ret = 1;
1489 goto out;
1490 rollback: /* rollback all changes made, ignore further errors */
1491 for (i--; i >= 0; i--) {
1492 cd = get_column_description(t->desc, i);
1493 enum osl_storage_type st = cd->storage_type;
1494 if (st == OSL_NO_STORAGE)
1495 continue;
1496
1497 if (st == OSL_MAPPED_STORAGE)
1498 truncate_mapped_file(t, i, objects[i].size);
1499 else /* disk storage */
1500 delete_disk_storage_file(t, i, ds_name);
1501 }
1502 /* ignore error and return previous error value */
1503 map_table(t, MAP_TBL_FL_VERIFY_INDEX);
1504 out:
1505 free(new_row_index);
1506 free(ds_name);
1507 free(rb_parents);
1508 free(rb_links);
1509 return ret;
1510 }
1511
1512 /**
1513 * Add a new row to an osl table.
1514 *
1515 * \param t Same meaning as osl_add_and_get_row().
1516 * \param objects Same meaning as osl_add_and_get_row().
1517 *
1518 * \return The return value of the underlying call to osl_add_and_get_row().
1519 *
1520 * This is equivalent to osl_add_and_get_row(t, objects, NULL).
1521 */
1522 int osl_add_row(struct osl_table *t, struct osl_object *objects)
1523 {
1524 return osl_add_and_get_row(t, objects, NULL);
1525 }
1526
1527 /**
1528 * Retrieve an object identified by row and column
1529 *
1530 * \param t Pointer to an open osl table.
1531 * \param r Pointer to the row.
1532 * \param col_num The column number.
1533 * \param object The result pointer.
1534 *
1535 * The column determined by \a col_num must be of type \p OSL_MAPPED_STORAGE
1536 * or \p OSL_NO_STORAGE, i.e. no disk storage objects may be retrieved by this
1537 * function.
1538 *
1539 * \return Positive if object was found, negative on errors. Possible errors
1540 * include: \p E_BAD_TABLE, \p E_BAD_STORAGE_TYPE.
1541 *
1542 * \sa osl_storage_type, osl_open_disk_object().
1543 */
1544 int osl_get_object(const struct osl_table *t, const struct osl_row *r,
1545 unsigned col_num, struct osl_object *object)
1546 {
1547 const struct osl_column_description *cd;
1548
1549 if (!t)
1550 return -E_BAD_TABLE;
1551 cd = get_column_description(t->desc, col_num);
1552 /* col must not be disk storage */
1553 if (cd->storage_type == OSL_DISK_STORAGE)
1554 return -E_BAD_STORAGE_TYPE;
1555 if (cd->storage_type == OSL_MAPPED_STORAGE)
1556 return get_mapped_object(t, col_num, r->num, object);
1557 /* volatile */
1558 *object = r->volatile_objects[t->columns[col_num].volatile_num];
1559 return 1;
1560 }
1561
1562 static int mark_mapped_object_invalid(const struct osl_table *t,
1563 uint32_t row_num, unsigned col_num)
1564 {
1565 struct osl_object obj;
1566 char *p;
1567 int ret = get_mapped_object(t, col_num, row_num, &obj);
1568
1569 if (ret < 0)
1570 return ret;
1571 p = obj.data;
1572 p--;
1573 *p = 0xff;
1574 return 1;
1575 }
1576
1577 /**
1578 * Delete a row from an osl table.
1579 *
1580 * \param t Pointer to an open osl table.
1581 * \param row Pointer to the row to delete.
1582 *
1583 * This removes all disk storage objects, removes all rbtree nodes, and frees
1584 * all volatile objects belonging to the given row. For mapped columns, the
1585 * data is merely marked invalid and may be pruned from time to time by
1586 * para_fsck.
1587 *
1588 * \return Positive on success, negative on errors. Possible errors include:
1589 * \p E_BAD_TABLE, errors returned by osl_get_object().
1590 */
1591 int osl_del_row(struct osl_table *t, struct osl_row *row)
1592 {
1593 struct osl_row *r = row;
1594 int i, ret;
1595 const struct osl_column_description *cd;
1596
1597 if (!t)
1598 return -E_BAD_TABLE;
1599 PARA_INFO_LOG("deleting row %p\n", row);
1600
1601 if (t->num_disk_storage_columns) {
1602 char *ds_name;
1603 ret = disk_storage_name_of_row(t, r, &ds_name);
1604 if (ret < 0)
1605 goto out;
1606 FOR_EACH_DISK_STORAGE_COLUMN(i, t, cd)
1607 delete_disk_storage_file(t, i, ds_name);
1608 free(ds_name);
1609 }
1610 FOR_EACH_COLUMN(i, t->desc, cd) {
1611 struct osl_column *col = t->columns + i;
1612 enum osl_storage_type st = cd->storage_type;
1613 remove_rb_node(t, i, r);
1614 if (st == OSL_MAPPED_STORAGE) {
1615 mark_mapped_object_invalid(t, r->num, i);
1616 continue;
1617 }
1618 if (st == OSL_NO_STORAGE)
1619 free(r->volatile_objects[col->volatile_num].data);
1620 }
1621 if (t->num_mapped_columns) {
1622 ret = mark_row_invalid(t, r->num);
1623 if (ret < 0)
1624 goto out;
1625 t->num_invalid_rows++;
1626 } else
1627 t->num_rows--;
1628 ret = 1;
1629 out:
1630 free(r->volatile_objects);
1631 free(r);
1632 return ret;
1633 }
1634
1635 /* test if column has an rbtree */
1636 static int check_rbtree_col(const struct osl_table *t, unsigned col_num,
1637 struct osl_column **col)
1638 {
1639 if (!t)
1640 return -E_BAD_TABLE;
1641 if (!(get_column_description(t->desc, col_num)->storage_flags & OSL_RBTREE))
1642 return -E_BAD_STORAGE_FLAGS;
1643 *col = t->columns + col_num;
1644 return 1;
1645 }
1646
1647 /**
1648 * Get the row that contains the given object.
1649 *
1650 * \param t Pointer to an open osl table.
1651 * \param col_num The number of the column to be searched.
1652 * \param obj The object to be looked up.
1653 * \param result Points to the row containing \a obj.
1654 *
1655 * Lookup \a obj in \a t and return the row containing \a obj. The column
1656 * specified by \a col_num must have an associated rbtree.
1657 *
1658 * \return Positive on success, negative on errors. If an error occurred, \a
1659 * result is set to \p NULL. Possible errors include: \p E_BAD_TABLE, \p
1660 * E_BAD_STORAGE_FLAGS, errors returned by get_mapped_object(), \p
1661 * E_RB_KEY_NOT_FOUND.
1662 *
1663 * \sa osl_storage_flags
1664 */
1665 int osl_get_row(const struct osl_table *t, unsigned col_num,
1666 const struct osl_object *obj, struct osl_row **result)
1667 {
1668 int ret;
1669 struct rb_node *node;
1670 struct osl_row *row;
1671 struct osl_column *col;
1672
1673 *result = NULL;
1674 ret = check_rbtree_col(t, col_num, &col);
1675 if (ret < 0)
1676 return ret;
1677 ret = search_rbtree(obj, t, col_num, &node, NULL);
1678 if (ret < 0)
1679 return ret;
1680 row = get_row_pointer(node, t->columns[col_num].rbtree_num);
1681 *result = row;
1682 return 1;
1683 }
1684
1685 static int rbtree_loop(struct osl_column *col, void *private_data,
1686 osl_rbtree_loop_func *func)
1687 {
1688 struct rb_node *n, *tmp;
1689
1690 /* this for-loop is safe against removal of an entry */
1691 for (n = rb_first(&col->rbtree), tmp = n? rb_next(n) : NULL;
1692 n;
1693 n = tmp, tmp = tmp? rb_next(tmp) : NULL) {
1694 struct osl_row *r = get_row_pointer(n, col->rbtree_num);
1695 int ret = func(r, private_data);
1696 if (ret < 0)
1697 return ret;
1698 }
1699 return 1;
1700 }
1701
1702 static int rbtree_loop_reverse(struct osl_column *col, void *private_data,
1703 osl_rbtree_loop_func *func)
1704 {
1705 struct rb_node *n, *tmp;
1706
1707 /* safe against removal of an entry */
1708 for (n = rb_last(&col->rbtree), tmp = n? rb_prev(n) : NULL;
1709 n;
1710 n = tmp, tmp = tmp? rb_prev(tmp) : NULL) {
1711 struct osl_row *r = get_row_pointer(n, col->rbtree_num);
1712 int ret = func(r, private_data);
1713 if (ret < 0)
1714 return ret;
1715 }
1716 return 1;
1717 }
1718
1719 /**
1720 * Loop over all nodes in an rbtree.
1721 *
1722 * \param t Pointer to an open osl table.
1723 * \param col_num The column to use for iterating over the elements.
1724 * \param private_data Pointer that gets passed to \a func.
1725 * \param func The function to be called for each node in the rbtree.
1726 *
1727 * This function does an in-order walk of the rbtree associated with \a
1728 * col_num. It is an error if the \p OSL_RBTREE flag is not set for this
1729 * column. For each node in the rbtree, the given function \a func is called
1730 * with two pointers as arguments: The first osl_row* argument points to the
1731 * row that contains the object corresponding to the rbtree node currently
1732 * traversed, and the \a private_data pointer is passed verbatim to \a func as the
1733 * second argument. The loop terminates either if \a func returns a negative
1734 * value, or if all nodes of the tree have been visited.
1735 *
1736 *
1737 * \return Positive on success, negative on errors. If the termination of the
1738 * loop was caused by \a func returning a negative value, this value is
1739 * returned.
1740 *
1741 * \sa osl_storage_flags, osl_rbtree_loop_reverse(), osl_compare_func.
1742 */
1743 int osl_rbtree_loop(const struct osl_table *t, unsigned col_num,
1744 void *private_data, osl_rbtree_loop_func *func)
1745 {
1746 struct osl_column *col;
1747
1748 int ret = check_rbtree_col(t, col_num, &col);
1749 if (ret < 0)
1750 return ret;
1751 return rbtree_loop(col, private_data, func);
1752 }
1753
1754 /**
1755 * Loop over all nodes in an rbtree in reverse order.
1756 *
1757 * \param t Identical meaning as in \p osl_rbtree_loop().
1758 * \param col_num Identical meaning as in \p osl_rbtree_loop().
1759 * \param private_data Identical meaning as in \p osl_rbtree_loop().
1760 * \param func Identical meaning as in \p osl_rbtree_loop().
1761 *
1762 * This function is identical to \p osl_rbtree_loop(), the only difference
1763 * is that the tree is walked in reverse order.
1764 *
1765 * \return The same return value as \p osl_rbtree_loop().
1766 *
1767 * \sa osl_rbtree_loop().
1768 */
1769 int osl_rbtree_loop_reverse(const struct osl_table *t, unsigned col_num,
1770 void *private_data, osl_rbtree_loop_func *func)
1771 {
1772 struct osl_column *col;
1773
1774 int ret = check_rbtree_col(t, col_num, &col);
1775 if (ret < 0)
1776 return ret;
1777 return rbtree_loop_reverse(col, private_data, func);
1778 }
1779
1780 /* TODO: Rollback changes on errors */
1781 static int rename_disk_storage_objects(struct osl_table *t,
1782 struct osl_object *old_obj, struct osl_object *new_obj)
1783 {
1784 int i, ret;
1785 const struct osl_column_description *cd;
1786 char *old_ds_name, *new_ds_name;
1787
1788 if (!t->num_disk_storage_columns)
1789 return 1; /* nothing to do */
1790 if (old_obj->size == new_obj->size && !memcmp(new_obj->data,
1791 old_obj->data, new_obj->size))
1792 return 1; /* object did not change */
1793 old_ds_name = disk_storage_name_of_object(t, old_obj);
1794 new_ds_name = disk_storage_name_of_object(t, new_obj);
1795 FOR_EACH_DISK_STORAGE_COLUMN(i, t, cd) {
1796 char *old_filename, *new_filename;
1797 ret = create_disk_storage_object_dir(t, i, new_ds_name);
1798 if (ret < 0)
1799 goto out;
1800 old_filename = disk_storage_path(t, i, old_ds_name);
1801 new_filename = disk_storage_path(t, i, new_ds_name);
1802 ret = para_rename(old_filename, new_filename);
1803 free(old_filename);
1804 free(new_filename);
1805 if (ret < 0)
1806 goto out;
1807 }
1808 ret = 1;
1809 out:
1810 free(old_ds_name);
1811 free(new_ds_name);
1812 return ret;
1813
1814 }
1815
1816 /**
1817 * Change an object in an osl table.
1818 *
1819 * \param t Pointer to an open osl table.
1820 * \param r Pointer to the row containing the object to be updated.
1821 * \param col_num Number of the column containing the object to be updated.
1822 * \param obj Pointer to the replacement object.
1823 *
1824 * This function gets rid of all references to the old object. This includes
1825 * removal of the rbtree node in case there is an rbtree associated with \a
1826 * col_num. It then inserts \a obj into the table and the rbtree if necessary.
1827 *
1828 * If the \p OSL_RBTREE flag is set for \a col_num, you \b MUST call this
1829 * function in order to change the contents of an object, even for volatile or
1830 * mapped columns of constant size (which may be updated directly if \p
1831 * OSL_RBTREE is not set). Otherwise the rbtree might become corrupted.
1832 *
1833 * \return Standard
1834 */
1835 int osl_update_object(struct osl_table *t, const struct osl_row *r,
1836 unsigned col_num, struct osl_object *obj)
1837 {
1838 struct osl_column *col;
1839 const struct osl_column_description *cd;
1840 int ret;
1841
1842 if (!t)
1843 return -E_BAD_TABLE;
1844 col = &t->columns[col_num];
1845 cd = get_column_description(t->desc, col_num);
1846 PARA_DEBUG_LOG("updating column %u of %s\n", col_num, t->desc->name);
1847 if (cd->storage_flags & OSL_RBTREE) {
1848 if (search_rbtree(obj, t, col_num, NULL, NULL) > 0)
1849 return -E_RB_KEY_EXISTS;
1850 }
1851 if (cd->storage_flags & OSL_FIXED_SIZE) {
1852 if (obj->size != cd->data_size)
1853 return -E_BAD_DATA_SIZE;
1854 }
1855 remove_rb_node(t, col_num, r);
1856 if (cd->storage_type == OSL_NO_STORAGE) { /* TODO: If fixed size, reuse object? */
1857 free(r->volatile_objects[col->volatile_num].data);
1858 r->volatile_objects[col->volatile_num] = *obj;
1859 } else if (cd->storage_type == OSL_DISK_STORAGE) {
1860 char *ds_name;
1861 ret = disk_storage_name_of_row(t, r, &ds_name);
1862 if (ret < 0)
1863 return ret;
1864 ret = delete_disk_storage_file(t, col_num, ds_name);
1865 if (ret < 0 && !is_errno(-ret, ENOENT)) {
1866 free(ds_name);
1867 return ret;
1868 }
1869 ret = write_disk_storage_file(t, col_num, obj, ds_name);
1870 free(ds_name);
1871 if (ret < 0)
1872 return ret;
1873 } else { /* mapped storage */
1874 struct osl_object old_obj;
1875 ret = get_mapped_object(t, col_num, r->num, &old_obj);
1876 if (ret < 0)
1877 return ret;
1878 /*
1879 * If the updated column is the disk storage name column, the
1880 * disk storage name changes, so we have to rename all disk
1881 * storage objects accordingly.
1882 */
1883 if (col_num == t->disk_storage_name_column) {
1884 ret = rename_disk_storage_objects(t, &old_obj, obj);
1885 if (ret < 0)
1886 return ret;
1887 }
1888 if (cd->storage_flags & OSL_FIXED_SIZE)
1889 memcpy(old_obj.data, obj->data, cd->data_size);
1890 else { /* TODO: if the size doesn't change, use old space */
1891 uint32_t new_data_map_size;
1892 char *row_index;
1893 ret = get_row_index(t, r->num, &row_index);
1894 if (ret < 0)
1895 return ret;
1896 ret = mark_mapped_object_invalid(t, r->num, col_num);
1897 if (ret < 0)
1898 return ret;
1899 unmap_column(t, col_num);
1900 ret = append_map_file(t, col_num, obj,
1901 &new_data_map_size);
1902 if (ret < 0)
1903 return ret;
1904 ret = map_column(t, col_num);
1905 if (ret < 0)
1906 return ret;
1907 update_cell_index(row_index, col, new_data_map_size,
1908 obj->size);
1909 }
1910 }
1911 if (cd->storage_flags & OSL_RBTREE) {
1912 ret = insert_rbtree(t, col_num, r, obj);
1913 if (ret < 0)
1914 return ret;
1915 }
1916 return 1;
1917 }
1918
1919 /**
1920 * Retrieve an object of type \p OSL_DISK_STORAGE by row and column.
1921 *
1922 * \param t Pointer to an open osl table.
1923 * \param r Pointer to the row containing the object.
1924 * \param col_num The column number.
1925 * \param obj Points to the result upon successful return.
1926 *
1927 * For columns of type \p OSL_DISK_STORAGE, this function must be used to
1928 * retrieve one of its containing objects. Afterwards, osl_close_disk_object()
1929 * must be called in order to deallocate the resources.
1930 *
1931 * \return Positive on success, negative on errors. Possible errors include:
1932 * \p E_BAD_TABLE, \p E_BAD_STORAGE_TYPE, errors returned by osl_get_object().
1933 *
1934 * \sa osl_get_object(), osl_storage_type, osl_close_disk_object().
1935 */
1936 int osl_open_disk_object(const struct osl_table *t, const struct osl_row *r,
1937 unsigned col_num, struct osl_object *obj)
1938 {
1939 const struct osl_column_description *cd;
1940 char *ds_name, *filename;
1941 int ret;
1942
1943 if (!t)
1944 return -E_BAD_TABLE;
1945 cd = get_column_description(t->desc, col_num);
1946 if (cd->storage_type != OSL_DISK_STORAGE)
1947 return -E_BAD_STORAGE_TYPE;
1948
1949 ret = disk_storage_name_of_row(t, r, &ds_name);
1950 if (ret < 0)
1951 return ret;
1952 filename = disk_storage_path(t, col_num, ds_name);
1953 free(ds_name);
1954 PARA_DEBUG_LOG("filename: %s\n", filename);
1955 ret = mmap_full_file(filename, O_RDONLY, obj);
1956 free(filename);
1957 return ret;
1958 }
1959
1960 /**
1961 * Free resources that were allocated during osl_open_disk_object().
1962 *
1963 * \param obj Pointer to the object previously returned by open_disk_object().
1964 *
1965 * \return The return value of the underlying call to para_munmap().
1966 *
1967 * \sa para_munmap().
1968 */
1969 int osl_close_disk_object(struct osl_object *obj)
1970 {
1971 return para_munmap(obj->data, obj->size);
1972 }
1973
1974 /**
1975 * Get the number of rows of the given table.
1976 *
1977 * \param t Pointer to an open osl table.
1978 * \param num_rows Result is returned here.
1979 *
1980 * The number of rows returned via \a num_rows excluding any invalid rows.
1981 *
1982 * \return Positive on success, \p -E_BAD_TABLE if \a t is \p NULL.
1983 */
1984 int osl_get_num_rows(const struct osl_table *t, unsigned *num_rows)
1985 {
1986 if (!t)
1987 return -E_BAD_TABLE;
1988 assert(t->num_rows >= t->num_invalid_rows);
1989 *num_rows = t->num_rows - t->num_invalid_rows;
1990 return 1;
1991 }
1992
1993 /**
1994 * Get the rank of a row.
1995 *
1996 * \param t An open osl table.
1997 * \param r The row to get the rank of.
1998 * \param col_num The number of an rbtree column.
1999 * \param rank Result pointer.
2000 *
2001 * The rank is, by definition, the position of the row in the linear order
2002 * determined by an in-order tree walk of the rbtree associated with column
2003 * number \a col_num of \a table.
2004 *
2005 * \return Positive on success, negative on errors.
2006 *
2007 * \sa osl_get_nth_row().
2008 */
2009 int osl_get_rank(const struct osl_table *t, struct osl_row *r,
2010 unsigned col_num, unsigned *rank)
2011 {
2012 struct osl_object obj;
2013 struct osl_column *col;
2014 struct rb_node *node;
2015 int ret = check_rbtree_col(t, col_num, &col);
2016
2017 if (ret < 0)
2018 return ret;
2019 ret = osl_get_object(t, r, col_num, &obj);
2020 if (ret < 0)
2021 return ret;
2022 ret = search_rbtree(&obj, t, col_num, &node, NULL);
2023 if (ret < 0)
2024 return ret;
2025 ret = rb_rank(node, rank);
2026 if (ret < 0)
2027 return -E_BAD_ROW;
2028 return 1;
2029 }
2030
2031 /**
2032 * Get the row with n-th greatest value.
2033 *
2034 * \param t Pointer to an open osl table.
2035 * \param col_num The column number.
2036 * \param n The rank of the desired row.
2037 * \param result Row is returned here.
2038 *
2039 * Retrieve the n-th order statistic with respect to the compare function
2040 * of the rbtree column \a col_num. In other words, get that row with
2041 * \a n th greatest value in column \a col_num. It's an error if
2042 * \a col_num is not a rbtree column, or if \a n is larger than the
2043 * number of rows in the table.
2044 *
2045 * \return Positive on success, negative on errors. Possible errors:
2046 * \p E_BAD_TABLE, \p E_BAD_STORAGE_FLAGS, \p E_RB_KEY_NOT_FOUND.
2047 *
2048 * \sa osl_storage_flags, osl_compare_func, osl_get_row(),
2049 * osl_rbtree_last_row(), osl_rbtree_first_row(), osl_get_rank().
2050 */
2051 int osl_get_nth_row(const struct osl_table *t, unsigned col_num,
2052 unsigned n, struct osl_row **result)
2053 {
2054 struct osl_column *col;
2055 struct rb_node *node;
2056 int ret = check_rbtree_col(t, col_num, &col);
2057
2058 if (ret < 0)
2059 return ret;
2060 node = rb_nth(col->rbtree.rb_node, n);
2061 if (!node)
2062 return -E_RB_KEY_NOT_FOUND;
2063 *result = get_row_pointer(node, col->rbtree_num);
2064 return 1;
2065 }
2066
2067 /**
2068 * Get the row corresponding to the smallest rbtree node of a column.
2069 *
2070 * \param t An open rbtree table.
2071 * \param col_num The number of the rbtree column.
2072 * \param result A pointer to the first row is returned here.
2073 *
2074 * The rbtree node of the smallest object (with respect to the corresponding
2075 * compare function) is selected and the row containing this object is
2076 * returned. It is an error if \a col_num refers to a column without an
2077 * associated rbtree.
2078 *
2079 * \return Positive on success, negative on errors.
2080 *
2081 * \sa osl_get_nth_row(), osl_rbtree_last_row().
2082 */
2083 int osl_rbtree_first_row(const struct osl_table *t, unsigned col_num,
2084 struct osl_row **result)
2085 {
2086 return osl_get_nth_row(t, col_num, 1, result);
2087 }
2088
2089 /**
2090 * Get the row corresponding to the greatest rbtree node of a column.
2091 *
2092 * \param t The same meaning as in \p osl_rbtree_first_row().
2093 * \param col_num The same meaning as in \p osl_rbtree_first_row().
2094 * \param result The same meaning as in \p osl_rbtree_first_row().
2095 *
2096 * This function works just like osl_rbtree_first_row(), the only difference
2097 * is that the row containing the greatest rather than the smallest object is
2098 * returned.
2099 *
2100 * \return Positive on success, negative on errors.
2101 *
2102 * \sa osl_get_nth_row(), osl_rbtree_first_row().
2103 */
2104 int osl_rbtree_last_row(const struct osl_table *t, unsigned col_num,
2105 struct osl_row **result)
2106 {
2107 unsigned num_rows;
2108 int ret = osl_get_num_rows(t, &num_rows);
2109
2110 if (ret < 0)
2111 return ret;
2112 return osl_get_nth_row(t, col_num, num_rows, result);
2113 }