summaryrefslogtreecommitdiffstats
path: root/src/H5Plapl.c
blob: 6c8049314654c5120fe22221c6cf7b4cacaaa1c3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * Copyright by the Board of Trustees of the University of Illinois.         *
 * All rights reserved.                                                      *
 *                                                                           *
 * This file is part of HDF5.  The full HDF5 copyright notice, including     *
 * terms governing use, modification, and redistribution, is contained in    *
 * the files COPYING and Copyright.html.  COPYING can be found at the root   *
 * of the source code distribution tree; Copyright.html can be found at the  *
 * root level of an installed copy of the electronic HDF5 document set and   *
 * is linked from the top-level documents page.  It can also be found at     *
 * http://hdfgroup.org/HDF5/doc/Copyright.html.  If you do not have          *
 * access to either file, you may request a copy from help@hdfgroup.org.     *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*-------------------------------------------------------------------------
 *
 * Created:		H5Plapl.c
 *			July 14 2006
 *			James Laird <jlaird@ncsa.uiuc.edu>
 *
 * Purpose:		Link access property list class routines
 *
 *-------------------------------------------------------------------------
 */

/****************/
/* Module Setup */
/****************/
#define H5P_PACKAGE		/*suppress error about including H5Ppkg	  */

/***********/
/* Headers */
/***********/
#include "H5private.h"		/* Generic Functions			*/
#include "H5Eprivate.h"		/* Error handling		  	*/
#include "H5Iprivate.h"		/* IDs			  		*/
#include "H5Lprivate.h"		/* Links		  		*/
#include "H5MMprivate.h"	/* Memory management			*/
#include "H5Ppkg.h"		/* Property lists		  	*/


/****************/
/* Local Macros */
/****************/

/* ========  Link access properties ======== */
/* Definitions for number of soft links to traverse */
#define H5L_ACS_NLINKS_SIZE        sizeof(size_t)
#define H5L_ACS_NLINKS_DEF         H5L_NUM_LINKS /*max symlinks to follow per lookup  */
/* Definitions for external link prefix */
#define H5L_ACS_ELINK_PREFIX_SIZE        sizeof(char *)
#define H5L_ACS_ELINK_PREFIX_DEF         NULL /*default is no prefix */
#define H5L_ACS_ELINK_PREFIX_DEL         H5P_lacc_elink_pref_del
#define H5L_ACS_ELINK_PREFIX_COPY        H5P_lacc_elink_pref_copy
#define H5L_ACS_ELINK_PREFIX_CLOSE       H5P_lacc_elink_pref_close

/* Definitions for setting fapl of external link access */
#define H5L_ACS_ELINK_FAPL_SIZE        	sizeof(hid_t)
#define H5L_ACS_ELINK_FAPL_DEF         	H5P_DEFAULT
#define H5L_ACS_ELINK_FAPL_DEL		H5P_lacc_elink_fapl_del
#define H5L_ACS_ELINK_FAPL_COPY        	H5P_lacc_elink_fapl_copy
#define H5L_ACS_ELINK_FAPL_CLOSE       	H5P_lacc_elink_fapl_close

/* Definitions for file access flags for external link traversal */
#define H5L_ACS_ELINK_FLAGS_SIZE        sizeof(unsigned)
#define H5L_ACS_ELINK_FLAGS_DEF         H5F_ACC_DEFAULT

/* Definitions for callback function for external link traversal */
#define H5L_ACS_ELINK_CB_SIZE           sizeof(H5L_elink_cb_t)
#define H5L_ACS_ELINK_CB_DEF            {NULL,NULL}

/******************/
/* Local Typedefs */
/******************/


/********************/
/* Package Typedefs */
/********************/


/********************/
/* Local Prototypes */
/********************/

/* Property class callbacks */
static herr_t H5P_lacc_reg_prop(H5P_genclass_t *pclass);

/* Property list callbacks */
static herr_t H5P_lacc_elink_pref_del(hid_t prop_id, const char* name, size_t size, void* value);
static herr_t H5P_lacc_elink_pref_copy(const char* name, size_t size, void* value);
static herr_t H5P_lacc_elink_pref_close(const char* name, size_t size, void* value);

static herr_t H5P_lacc_elink_fapl_del(hid_t prop_id, const char* name, size_t size, void* value);
static herr_t H5P_lacc_elink_fapl_copy(const char* name, size_t size, void* value);
static herr_t H5P_lacc_elink_fapl_close(const char* name, size_t size, void* value);


/*********************/
/* Package Variables */
/*********************/

/* Dataset creation property list class library initialization object */
const H5P_libclass_t H5P_CLS_LACC[1] = {{
    "link access",		/* Class name for debugging     */
    &H5P_CLS_ROOT_g,		/* Parent class ID              */
    &H5P_CLS_LINK_ACCESS_g,	/* Pointer to class ID          */
    &H5P_LST_LINK_ACCESS_g,	/* Pointer to default property list ID */
    H5P_lacc_reg_prop,		/* Default property registration routine */
    NULL,		        /* Class creation callback      */
    NULL,		        /* Class creation callback info */
    NULL,			/* Class copy callback          */
    NULL,		        /* Class copy callback info     */
    NULL,			/* Class close callback         */
    NULL 		        /* Class close callback info    */
}};


/*****************************/
/* Library Private Variables */
/*****************************/


/*******************/
/* Local Variables */
/*******************/



/*-------------------------------------------------------------------------
 * Function:    H5P_lacc_reg_prop
 *
 * Purpose:     Register the dataset creation property list class's properties
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Quincey Koziol
 *              October 31, 2006
 *
 * Modifications:
 *	Vailin Choi, Sept. 12th 2008
 *	Register the setting of file access property list for link access
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5P_lacc_reg_prop(H5P_genclass_t *pclass)
{
    size_t nlinks = H5L_ACS_NLINKS_DEF; 	   /* Default number of soft links to traverse */
    char *elink_prefix = H5L_ACS_ELINK_PREFIX_DEF; /* Default external link prefix string */
    hid_t def_fapl_id = H5L_ACS_ELINK_FAPL_DEF;    /* Default fapl for external link access */
    unsigned elink_flags = H5L_ACS_ELINK_FLAGS_DEF; /* Default file access flags for external link traversal */
    H5L_elink_cb_t elink_cb = H5L_ACS_ELINK_CB_DEF; /* Default external link traversal callback */

    herr_t ret_value = SUCCEED;         	   /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Register property for number of links traversed */
    if(H5P_register_real(pclass, H5L_ACS_NLINKS_NAME, H5L_ACS_NLINKS_SIZE, &nlinks, NULL, NULL, NULL, NULL, NULL, NULL, NULL) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")

    /* Register property for external link prefix */
    if(H5P_register_real(pclass, H5L_ACS_ELINK_PREFIX_NAME, H5L_ACS_ELINK_PREFIX_SIZE, &elink_prefix, NULL, NULL, NULL, H5L_ACS_ELINK_PREFIX_DEL, H5L_ACS_ELINK_PREFIX_COPY, NULL, H5L_ACS_ELINK_PREFIX_CLOSE) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")

    /* Register fapl for link access */
    if(H5P_register_real(pclass, H5L_ACS_ELINK_FAPL_NAME, H5L_ACS_ELINK_FAPL_SIZE, &def_fapl_id, NULL, NULL, NULL, H5L_ACS_ELINK_FAPL_DEL, H5L_ACS_ELINK_FAPL_COPY, NULL, H5L_ACS_ELINK_FAPL_CLOSE) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")

    /* Register property for external link file access flags */
    if(H5P_register_real(pclass, H5L_ACS_ELINK_FLAGS_NAME, H5L_ACS_ELINK_FLAGS_SIZE, &elink_flags, NULL, NULL, NULL, NULL, NULL, NULL, NULL) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")

    /* Register property for external link file traversal callback */
    if(H5P_register_real(pclass, H5L_ACS_ELINK_CB_NAME, H5L_ACS_ELINK_CB_SIZE, &elink_cb, NULL, NULL, NULL, NULL, NULL, NULL, NULL) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5P_lacc_reg_prop() */


/*--------------------------------------------------------------------------
 * Function:	H5P_lacc_elink_fapl_del
 *
 * Purpose:	Close the FAPL for link access
 *
 * Return:	Success:	Non-negative
 * 		Failure:	Negative
 *
 * Programmer:	Vailin Choi
 *		Tuesday, Sept 23, 2008
 *
 *--------------------------------------------------------------------------
 */
/* ARGSUSED */
static herr_t
H5P_lacc_elink_fapl_del(hid_t UNUSED prop_id, const char UNUSED *name, size_t UNUSED size, void *value)
{
    hid_t          l_fapl_id;
    herr_t         ret_value = SUCCEED;

    FUNC_ENTER_NOAPI(FAIL)

    HDassert(value);

    l_fapl_id = (*(const hid_t *)value);

    if((l_fapl_id > H5P_DEFAULT) && (H5I_dec_ref(l_fapl_id) < 0))
	HGOTO_ERROR(H5E_PLIST, H5E_CANTRELEASE, FAIL, "unable to close atom for file access property list")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5P_lacc_elink_fapl_del() */


/*--------------------------------------------------------------------------
 * Function:	H5P_lacc_elink_fapl_copy
 *
 * Purpose:	Copy the FAPL for link access
 *
 * Return:	Success:	Non-negative
 * 		Failure:	Negative
 *
 * Programmer:	Vailin Choi
 *		Tuesday, Sept 23, 2008
 *
 *--------------------------------------------------------------------------
 */
/* ARGSUSED */
static herr_t
H5P_lacc_elink_fapl_copy(const char UNUSED *name, size_t UNUSED size, void *value)
{
    hid_t          l_fapl_id;
    herr_t         ret_value = SUCCEED;

    FUNC_ENTER_NOAPI(FAIL)

    HDassert(value);

    l_fapl_id = (*(const hid_t *)value);

    if(l_fapl_id > H5P_DEFAULT) {
        H5P_genplist_t *l_fapl_plist;

        if(NULL == (l_fapl_plist = (H5P_genplist_t *)H5P_object_verify(l_fapl_id, H5P_FILE_ACCESS)))
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "can't get property list")

	if(((*(hid_t *)value) = H5P_copy_plist(l_fapl_plist, FALSE)) < 0)
	    HGOTO_ERROR(H5E_INTERNAL, H5E_CANTINIT, FAIL, "unable to copy file access properties")
    } /* end if */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5P_lacc_elink_fapl_copy() */


/*--------------------------------------------------------------------------
 * Function:	H5P_lacc_elink_fapl_close
 *
 * Purpose:	Close the FAPL for link access
 *
 * Return:	Success:	Non-negative
 * 		Failure:	Negative
 *
 * Programmer:	Vailin Choi
 *		Tuesday, Sept 23, 2008
 *
 *---------------------------------------------------------------------------
 */
/* ARGSUSED */
static herr_t
H5P_lacc_elink_fapl_close(const char UNUSED *name, size_t UNUSED size, void *value)
{
    hid_t		l_fapl_id;
    herr_t     		ret_value = SUCCEED;

    FUNC_ENTER_NOAPI_NOINIT

    HDassert(value);

    l_fapl_id = (*(const hid_t *)value);
    if((l_fapl_id > H5P_DEFAULT) && (H5I_dec_ref(l_fapl_id) < 0))
	HGOTO_ERROR(H5E_PLIST, H5E_CANTRELEASE, FAIL, "unable to close atom for file access property list")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5P_lacc_elink_fapl_close() */


/*-------------------------------------------------------------------------
 * Function:    H5P_lacc_elink_pref_del
 *
 * Purpose:     Frees memory used to store the external link prefix string
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Quincey Koziol
 *              November 2, 2006
 *
 *-------------------------------------------------------------------------
 */
/* ARGSUSED */
static herr_t
H5P_lacc_elink_pref_del(hid_t UNUSED prop_id, const char UNUSED *name, size_t UNUSED size, void *value)
{
    FUNC_ENTER_NOAPI_NOINIT_NOERR

    HDassert(value);

    H5MM_xfree(*(void **)value);

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5P_lacc_elink_pref_del() */


/*-------------------------------------------------------------------------
 * Function:    H5P_lacc_elink_pref_copy
 *
 * Purpose:     Creates a copy of the external link prefix string
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Quincey Koziol
 *              November 2, 2006
 *
 *-------------------------------------------------------------------------
 */
/* ARGSUSED */
static herr_t
H5P_lacc_elink_pref_copy(const char UNUSED *name, size_t UNUSED size, void *value)
{
    FUNC_ENTER_NOAPI_NOINIT_NOERR

    HDassert(value);

    *(char **)value = H5MM_xstrdup(*(const char **)value);

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5P_lacc_elink_pref_copy() */


/*-------------------------------------------------------------------------
 * Function:    H5P_lacc_elink_pref_close
 *
 * Purpose:     Frees memory used to store the external link prefix string
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Quincey Koziol
 *              November 2, 2006
 *
 *-------------------------------------------------------------------------
 */
/* ARGSUSED */
static herr_t
H5P_lacc_elink_pref_close(const char UNUSED *name, size_t UNUSED size, void *value)
{
    FUNC_ENTER_NOAPI_NOINIT_NOERR

    HDassert(value);

    H5MM_xfree(*(void **)value);

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5P_lacc_elink_pref_close() */


/*-------------------------------------------------------------------------
 * Function:    H5Pset_nlinks
 *
 * Purpose:     Set the number of soft or UD link traversals allowed before
 *              the library assumes it has found a cycle and aborts the
 *              traversal.
 *
 *              The limit on soft or UD link traversals is designed to
 *              terminate link traversal if one or more links form a cycle.
 *              However, users may have a file with a legitimate path
 *              formed of a large number of soft or user-defined links.
 *              This property can be used to allow traversal of as many
 *              links as desired.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	James Laird
 *              Friday, July 14, 2006
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Pset_nlinks(hid_t plist_id, size_t nlinks)
{
    H5P_genplist_t *plist;              /* Property list pointer */
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE2("e", "iz", plist_id, nlinks);

    if(nlinks <= 0)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "number of links must be positive");

    /* Get the plist structure */
    if(NULL == (plist = H5P_object_verify(plist_id, H5P_LINK_ACCESS)))
        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")

    /* Set number of links */
    if(H5P_set(plist, H5L_ACS_NLINKS_NAME, &nlinks) < 0)
        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set nlink info")

done:
    FUNC_LEAVE_API(ret_value)
} /* end H5Pset_nlinks() */


/*-------------------------------------------------------------------------
 * Function:    H5Pget_nlinks
 *
 * Purpose:	Gets the number of soft or user-defined links that can be
 *              traversed before a failure occurs.
 *
 *              Retrieves the current setting for the nlinks property on
 *              the given property list.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	James Laird
 *              Friday, July 14, 2006
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Pget_nlinks(hid_t plist_id, size_t *nlinks)
{
    H5P_genplist_t *plist;              /* Property list pointer */
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE2("e", "i*z", plist_id, nlinks);

    if(!nlinks)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid pointer passed in");

    /* Get the plist structure */
    if(NULL == (plist = H5P_object_verify(plist_id, H5P_LINK_ACCESS)))
        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")

    /* Get the current number of links */
    if(H5P_get(plist, H5L_ACS_NLINKS_NAME, nlinks) < 0)
        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get number of links")

done:
    FUNC_LEAVE_API(ret_value)
}


/*-------------------------------------------------------------------------
 * Function:    H5Pset_elink_prefix
 *
 * Purpose:     Set a prefix to be applied to the path of any external links
 *              traversed.  The prefix is appended to the filename stored
 *              in the external link.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	James Laird
 *              Thursday, August 3, 2006
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Pset_elink_prefix(hid_t plist_id, const char *prefix)
{
    H5P_genplist_t *plist;              /* Property list pointer */
    char *my_prefix;                    /* Copy of prefix string */
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE2("e", "i*s", plist_id, prefix);

    /* Get the plist structure */
    if(NULL == (plist = H5P_object_verify(plist_id, H5P_LINK_ACCESS)))
        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")

    /* Get current prefix value */
    if(H5P_get(plist, H5L_ACS_ELINK_PREFIX_NAME, &my_prefix) < 0)
        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get prefix info")

    /* Free existing prefix, if there is one */
    H5MM_xfree(my_prefix);

    /* Make a copy of the user's prefix string */
    if(NULL == (my_prefix = H5MM_xstrdup(prefix)))
        HGOTO_ERROR(H5E_PLIST, H5E_CANTCOPY, FAIL, "can't copy prefix")

    /* Set prefix */
    if(H5P_set(plist, H5L_ACS_ELINK_PREFIX_NAME, &my_prefix) < 0)
        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set prefix info")

done:
    FUNC_LEAVE_API(ret_value)
} /* end H5Pset_elink_prefix() */


/*-------------------------------------------------------------------------
 * Function:    H5Pget_elink_prefix
 *
 * Purpose:	Gets the prefix to be applied to any external link
 *              traversals made using this property list.
 *
 *              If the pointer is not NULL, it points to a user-allocated
 *              buffer.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	James Laird
 *              Thursday, August 3, 2006
 *
 *-------------------------------------------------------------------------
 */
ssize_t
H5Pget_elink_prefix(hid_t plist_id, char *prefix, size_t size)
{
    H5P_genplist_t *plist;              /* Property list pointer */
    char *my_prefix;                    /* Library's copy of the prefix */
    size_t	len;                    /* Length of prefix string */
    ssize_t 	ret_value;              /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE3("Zs", "i*sz", plist_id, prefix, size);

    /* Get the plist structure */
    if(NULL == (plist = H5P_object_verify(plist_id, H5P_LINK_ACCESS)))
        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")

    /* Get the current prefix */
    if(H5P_get(plist, H5L_ACS_ELINK_PREFIX_NAME, &my_prefix) < 0)
        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get external link prefix")

    /* Check for prefix being set */
    if(my_prefix) {
        /* Copy to user's buffer, if given */
        len = HDstrlen(my_prefix);
        if(prefix) {
            HDstrncpy(prefix, my_prefix, MIN(len + 1, size));
            if(len >= size)
                prefix[size - 1] = '\0';
        } /* end if */
    } /* end if */
    else
        len = 0;

    /* Set return value */
    ret_value = (ssize_t)len;

done:
    FUNC_LEAVE_API(ret_value)
} /* end H5Pget_elink_prefix() */

/*-------------------------------------------------------------------------
 * Function:    H5Pset_elink_fapl
 *
 * Purpose:     Sets the file access property list for link access
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:
 *              Vailin Choi; Tuesday, September 12th, 2008
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Pset_elink_fapl(hid_t lapl_id, hid_t fapl_id)
{
    H5P_genplist_t 	*plist, *fapl_plist;	/* Property list pointer */
    hid_t		l_fapl_id, new_fapl_id;
    herr_t 		ret_value = SUCCEED;         		/* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE2("e", "ii", lapl_id, fapl_id);

    /* Check arguments */
    if(NULL == (plist = H5P_object_verify(lapl_id, H5P_LINK_ACCESS)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a link access property list");

    /* Get the current file access property list for the link access */
    if(H5P_get(plist, H5L_ACS_ELINK_FAPL_NAME, &l_fapl_id) < 0)
        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get fapl")

    /* Close the current file access property list if set */
    if((l_fapl_id > H5P_DEFAULT) && (H5I_dec_ref(l_fapl_id) < 0))
	HGOTO_ERROR(H5E_PLIST, H5E_CANTRELEASE, FAIL, "unable to close atom for file access property list")

    if(NULL == (fapl_plist = H5P_object_verify(fapl_id, H5P_FILE_ACCESS)))
	HGOTO_ERROR(H5E_PLIST, H5E_BADTYPE, FAIL, "not a file access property list");

    /* Make a copy of the property list for FAPL_ID */
    if((new_fapl_id = H5P_copy_plist(fapl_plist, FALSE)) < 0)
	HGOTO_ERROR(H5E_PLIST, H5E_CANTINIT, FAIL, "unable to copy file access properties")

    /* Set the file access property list for the link access */
    if(H5P_set(plist, H5L_ACS_ELINK_FAPL_NAME, &new_fapl_id) < 0)
        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set fapl for link")

done:
    FUNC_LEAVE_API(ret_value)
} /* end H5Pset_elink_fapl() */


/*-------------------------------------------------------------------------
 * Function:    H5Pget_elink_fapl
 *
 * Purpose:	Gets the file access property list identifier that is
 *		set for link access property.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:
 *              Vailin Choi; Tuesday, September 12th, 2008
 *
 *-------------------------------------------------------------------------
 */
hid_t
H5Pget_elink_fapl(hid_t lapl_id)
{
    H5P_genplist_t 	*plist, *fapl_plist; 	/* Property list pointer */
    hid_t		l_fapl_id;
    hid_t		ret_value=FAIL;		/* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE1("i", "i", lapl_id);

    /* Get the plist structure */
    if(NULL == (plist = H5P_object_verify(lapl_id, H5P_LINK_ACCESS)))
        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")

    if(H5P_get(plist, H5L_ACS_ELINK_FAPL_NAME, &l_fapl_id) < 0)
        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get fapl for links")

    if(l_fapl_id > H5P_DEFAULT) {
	if(NULL==(fapl_plist = H5P_object_verify(l_fapl_id, H5P_FILE_ACCESS)))
	    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file access property list");

	if((ret_value = H5P_copy_plist(fapl_plist, TRUE)) < 0)
	    HGOTO_ERROR(H5E_INTERNAL, H5E_CANTINIT, FAIL, "unable to copy file access properties")
    } else
	ret_value = l_fapl_id;

done:
    FUNC_LEAVE_API(ret_value);
} /* end H5Pget_elink_fapl() */


/*-------------------------------------------------------------------------
 * Function:    H5Pset_elink_acc_flags
 *
 * Purpose:     Sets the file access flags to be used when traversing an
 *              external link.  This should be either H5F_ACC_RDONLY or
 *              H5F_ACC_RDWR, or H5F_ACC_DEFAULT to unset the value.
 *
 * Return:  Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              Tuesday, December 9, 2008
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Pset_elink_acc_flags(hid_t lapl_id, unsigned flags)
{
    H5P_genplist_t *plist;              /* Property list pointer */
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE2("e", "iIu", lapl_id, flags);

    /* Check that flags are valid */
    if((flags != H5F_ACC_RDWR) && (flags != H5F_ACC_RDONLY) && (flags != H5F_ACC_DEFAULT))
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid file open flags")

    /* Get the plist structure */
    if(NULL == (plist = H5P_object_verify(lapl_id, H5P_LINK_ACCESS)))
        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")

    /* Set flags */
    if(H5P_set(plist, H5L_ACS_ELINK_FLAGS_NAME, &flags) < 0)
        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set access flags")

done:
    FUNC_LEAVE_API(ret_value)
} /* end H5Pset_elink_acc_flags() */


/*-------------------------------------------------------------------------
 * Function:    H5Pget_elink_acc_flags
 *
 * Purpose:     Gets the file access flags to be used when traversing an
 *              external link.
 *
 * Return:  Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              Tuesday, December 9, 2008
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Pget_elink_acc_flags(hid_t lapl_id, unsigned *flags)
{
    H5P_genplist_t *plist;              /* Property list pointer */
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE2("e", "i*Iu", lapl_id, flags);

    /* Get the plist structure */
    if(NULL == (plist = H5P_object_verify(lapl_id, H5P_LINK_ACCESS)))
        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")

    /* Get flags */
    if (flags)
        if(H5P_get(plist, H5L_ACS_ELINK_FLAGS_NAME, flags)<0)
            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, 0, "can't get access flags")

done:
    FUNC_LEAVE_API(ret_value)
} /* end H5Pget_elink_acc_flags() */


/*-------------------------------------------------------------------------
 * Function:    H5Pset_elink_cb
 *
 * Purpose:     Sets the file access flags to be used when traversing an
 *              external link.  This should be either H5F_ACC_RDONLY or
 *              H5F_ACC_RDWR.
 *
 * Return:  Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              Tuesday, December 15, 2008
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Pset_elink_cb(hid_t lapl_id, H5L_elink_traverse_t func, void *op_data)
{
    H5P_genplist_t  *plist;                 /* Property list pointer */
    H5L_elink_cb_t  cb_info;                /* Callback info struct */
    herr_t          ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE3("e", "ix*x", lapl_id, func, op_data);

    /* Check if the callback function is NULL and the user data is non-NULL.
     * This is almost certainly an error as the user data will not be used. */
    if(!func && op_data)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "callback is NULL while user data is not")

    /* Get the plist structure */
    if(NULL == (plist = H5P_object_verify(lapl_id, H5P_LINK_ACCESS)))
        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")

    /* Populate the callback info struct */
    cb_info.func = func;
    cb_info.user_data = op_data;

    /* Set callback info */
    if(H5P_set(plist, H5L_ACS_ELINK_CB_NAME, &cb_info) < 0)
        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set callback info")

done:
    FUNC_LEAVE_API(ret_value)
} /* end H5Pset_elink_acc_flags() */


/*-------------------------------------------------------------------------
 * Function:    H5Pget_elink_cb
 *
 * Purpose:     Gets the file access flags to be used when traversing an
 *              external link.
 *
 * Return:  Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              Tuesday, December 15, 2008
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Pget_elink_cb(hid_t lapl_id, H5L_elink_traverse_t *func, void **op_data)
{
    H5P_genplist_t  *plist;                 /* Property list pointer */
    H5L_elink_cb_t  cb_info;                /* Callback info struct */
    herr_t          ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE3("e", "i*x**x", lapl_id, func, op_data);

    /* Get the plist structure */
    if(NULL == (plist = H5P_object_verify(lapl_id, H5P_LINK_ACCESS)))
        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")

    /* Get callback_info */
    if(H5P_get(plist, H5L_ACS_ELINK_CB_NAME, &cb_info)<0)
        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get callback info")

    if(func)
        *func = cb_info.func;

    if(op_data)
        *op_data = cb_info.user_data;

done:
    FUNC_LEAVE_API(ret_value)
} /* end H5Pget_elink_cb() */