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6 .TH NVLIST_ALLOC 9F "Feb 15, 2016"
7 .SH NAME
8 nvlist_alloc, nvlist_free, nvlist_size, nvlist_pack, nvlist_unpack, nvlist_dup,
9 nv_alloc_init, nv_alloc_fini, nvlist_xalloc, nvlist_xpack, nvlist_xunpack,
10 nvlist_xdup, nvlist_merge \- Manage a name-value pair list
11 .SH SYNOPSIS
12 .LP
13 .nf
14 #include <sys/nvpair.h>
15
16 List Manipulation:
17
18 \fBint\fR \fBnvlist_alloc\fR(\fBnvlist_t **\fR\fInvlp\fR, \fBuint_t\fR \fInvflag\fR,
19 \fBint\fR \fIkmflag\fR);
20 .fi
21
22 .LP
23 .nf
24 \fBint\fR \fBnvlist_xalloc\fR(\fBnvlist_t **\fR\fInvlp\fR, \fBuint_t\fR \fInvflag\fR, \fBnv_alloc_t *\fR\fInva\fR);
25 .fi
26
27 .LP
28 .nf
29 \fBvoid\fR \fBnvlist_free\fR(\fBnvlist_t *\fR\fInvl\fR);
30 .fi
31
32 .LP
33 .nf
34 \fBint\fR \fBnvlist_size\fR(\fBnvlist_t *\fR\fInvl\fR, \fBsize_t *\fR\fIsize\fR, \fBint\fR \fIencoding\fR);
35 .fi
36
37 .LP
38 .nf
39 \fBint\fR \fBnvlist_pack\fR(\fBnvlist_t *\fR\fInvl\fR, \fBchar **\fR\fIbufp\fR, \fBsize_t *\fR\fIbuflen\fR, \fBint\fR \fIencoding\fR,
40 \fBint\fR \fIflag\fR);
41 .fi
42
43 .LP
44 .nf
45 \fBint\fR \fBnvlist_xpack\fR(\fBnvlist_t *\fR\fInvl\fR, \fBchar **\fR\fIbufp\fR, \fBsize_t *\fR\fIbuflen\fR, \fBint\fR \fIencoding\fR,
46 \fBnv_alloc_t *\fR\fInva\fR);
47 .fi
48
49 .LP
50 .nf
51 \fBint\fR \fBnvlist_unpack\fR(\fBchar *\fR\fIbuf\fR, \fBsize_t\fR \fIbuflen\fR, \fBnvlist_t **\fR\fInvlp\fR, \fBint\fR \fIflag\fR);
52 .fi
53
54 .LP
55 .nf
56 \fBint\fR \fBnvlist_xunpack\fR(\fBchar *\fR\fIbuf\fR, \fBsize_t\fR \fIbuflen\fR, \fBnvlist_t **\fR\fInvlp\fR,
57 \fBnv_alloc_t *\fR\fInva\fR);
58 .fi
59
60 .LP
61 .nf
62 \fBint\fR \fBnvlist_dup\fR(\fBnvlist_t *\fR\fInvl\fR, \fBnvlist_t **\fR\fInvlp\fR, \fBint\fR \fIflag\fR);
63 .fi
64
65 .LP
66 .nf
67 \fBint\fR \fBnvlist_xdup\fR(\fBnvlist_t *\fR\fInvl\fR, \fBnvlist_t **\fR\fInvlp\fR, \fBnv_alloc_t *\fR\fInva\fR);
68 .fi
69
70 .LP
71 .nf
72 \fBint\fR \fBnvlist_merge\fR(\fBnvlist_t *\fR\fIdst\fR, \fBnvlist_t *\fR\fInvl\fR, \fBint\fR \fIflag\fR);
73 .fi
74
75 .LP
76 .nf
77 Pluggable Allocator Configuration:
78
79 \fBnv_alloc_t *\fR\fBnvlist_lookup_nv_alloc\fR(\fBnvlist_t *);\fR
80 .fi
81
82 .LP
83 .nf
84 \fBint\fR \fBnv_alloc_init\fR(\fBnv_alloc_t *\fR\fInva\fR,
85 \fBconst nv_alloc_ops_t *\fR \fInvo,\fR/* args */ ...);
86 .fi
87
88 .LP
89 .nf
90 \fBvoid\fR \fBnv_alloc_reset\fR(\fBnv_alloc_t *\fR\fInva\fR);
91 .fi
92
93 .LP
94 .nf
95 \fBvoid\fR \fBnv_alloc_fini\fR(\fBnv_alloc_t *\fR\fInva\fR);
96 .fi
97
98 .LP
99 .nf
100 Pluggable Allocation Initialization with Fixed Allocator:
101
102 \fBint\fR \fBnv_alloc_init\fR(\fBnv_alloc_t *\fR\fInva\fR,
103 \fBnv_fixed_ops\fR, \fBvoid *\fR \fIbufptr\fR, \fBsize_t\fR sz);
104 .fi
105
106 .SH INTERFACE LEVEL
107 .sp
108 .LP
109 Solaris DDI specific (Solaris DDI)
110 .SH PARAMETERS
111 .sp
112 .ne 2
113 .na
114 \fB\fInvlp\fR\fR
115 .ad
116 .RS 12n
117 Address of a pointer to list of name-value pairs (\fBnvlist_t\fR).
118 .RE
119
120 .sp
121 .ne 2
122 .na
123 \fB\fInvflag\fR\fR
124 .ad
125 .RS 12n
126 Specify bit fields defining \fBnvlist_t\fR properties:
127 .sp
128 .ne 2
129 .na
130 \fB\fBNV_UNIQUE_NAME\fR\fR
131 .ad
132 .RS 23n
133 \fBnvpair\fR names are unique.
134 .RE
135
136 .sp
137 .ne 2
138 .na
139 \fB\fBNV_UNIQUE_NAME_TYPE\fR\fR
140 .ad
141 .RS 23n
142 Name-data type combination is unique
143 .RE
144
145 .RE
146
147 .sp
148 .ne 2
149 .na
150 \fB\fIkmflag\fR\fR
151 .ad
152 .RS 12n
153 Kernel memory allocation policy, either \fBKM_SLEEP\fR or \fBKM_NOSLEEP\fR.
154 .RE
155
156 .sp
157 .ne 2
158 .na
159 \fB\fInvl\fR\fR
160 .ad
161 .RS 12n
162 \fBnvlist_t\fR to be processed.
163 .RE
164
165 .sp
166 .ne 2
167 .na
168 \fB\fIdst\fR\fR
169 .ad
170 .RS 12n
171 Destination \fBnvlist_t\fR.
172 .RE
173
174 .sp
175 .ne 2
176 .na
177 \fB\fIsize\fR\fR
178 .ad
179 .RS 12n
180 Pointer to buffer to contain the encoded size.
181 .RE
182
183 .sp
184 .ne 2
185 .na
186 \fB\fIbufp\fR\fR
187 .ad
188 .RS 12n
189 Address of buffer to pack \fBnvlist\fR into. Must be 8-byte aligned. If NULL,
190 library will allocate memory.
191 .RE
192
193 .sp
194 .ne 2
195 .na
196 \fB\fIbuf\fR\fR
197 .ad
198 .RS 12n
199 Buffer containing packed \fBnvlist_t\fR.
200 .RE
201
202 .sp
203 .ne 2
204 .na
205 \fB\fIbuflen\fR\fR
206 .ad
207 .RS 12n
208 Size of buffer \fIbufp\fR or \fIbuf\fR points to.
209 .RE
210
211 .sp
212 .ne 2
213 .na
214 \fB\fIencoding\fR\fR
215 .ad
216 .RS 12n
217 Encoding method for packing.
218 .RE
219
220 .sp
221 .ne 2
222 .na
223 \fB\fInvo\fR\fR
224 .ad
225 .RS 12n
226 Pluggable allocator operations pointer (nv_alloc_ops_t).
227 .RE
228
229 .sp
230 .ne 2
231 .na
232 \fB\fInva\fR\fR
233 .ad
234 .RS 12n
235 Points to a nv_alloc_t structure to be used for the specified \fBnvlist_t\fR.
236 .RE
237
238 .SH DESCRIPTION
239 .sp
240 .LP
241 List Manipulation:
242 .sp
243 .LP
244 The \fBnvlist_alloc()\fR function allocates a new name-value pair list and
245 updates \fInvlp\fR to point to the handle. The argument \fInvflag\fR specifies
246 \fBnvlist_t\fR properties to remain persistent across packing, unpacking, and
247 duplication.
248 .sp
249 .LP
250 If \fBNV_UNIQUE_NAME\fR is specified for nvflag, existing nvpairs with matching
251 names are removed before the new nvpair is added. If \fBNV_UNIQUE_NAME_TYPE\fR
252 is specified for nvflag, existing nvpairs with matching names and data types
253 are removed before the new nvpair is added. See \fBnvlist_add_byte\fR(9F) for
254 more details.
255 .sp
256 .LP
257 The \fBnvlist_xalloc()\fR function differs from \fBnvlist_alloc()\fR in that
258 \fBnvlist_xalloc()\fR can use a different allocator, as described in the
259 Pluggable Allocators section.
260 .sp
261 .LP
262 The \fBnvlist_free()\fR function frees a name-value pair list. If \fInvl\fR
263 is a null pointer, no action occurs.
264 .sp
265 .LP
266 The \fBnvlist_size()\fR function returns the minimum size of a contiguous
267 buffer large enough to pack \fInvl\fR. The \fIencoding\fR parameter specifies
268 the method of encoding when packing \fInvl\fR. Supported encoding methods are:
269 .sp
270 .ne 2
271 .na
272 \fB\fBNV_ENCODE_NATIVE\fR\fR
273 .ad
274 .RS 20n
275 Straight \fBbcopy()\fR as described in \fBbcopy\fR(9F).
276 .RE
277
278 .sp
279 .ne 2
280 .na
281 \fB\fBNV_ENCODE_XDR\fR\fR
282 .ad
283 .RS 20n
284 Use XDR encoding, suitable for sending to another host.
285 .RE
286
287 .sp
288 .LP
289 The \fBnvlist_pack()\fR function packs \fInvl\fR into contiguous memory
290 starting at *\fIbufp\fR. The \fIencoding\fR parameter specifies the method of
291 encoding (see above).
292 .RS +4
293 .TP
294 .ie t \(bu
295 .el o
296 If *\fIbufp\fR is not NULL, *\fIbufp\fR is expected to be a caller-allocated
297 buffer of size *\fIbuflen\fR. The \fIkmflag\fR argument is ignored.
298 .RE
299 .RS +4
300 .TP
301 .ie t \(bu
302 .el o
303 If *\fIbufp\fR is NULL, the library allocates memory and updates *\fIbufp\fR to
304 point to the memory and updates *\fIbuflen\fR to contain the size of the
305 allocated memory. The value of \fIkmflag\fR indicates the memory allocation
306 policy
307 .RE
308 .sp
309 .LP
310 The \fBnvlist_xpack()\fR function differs from \fBnvlist_pack()\fR in that
311 \fBnvlist_xpack()\fR can use a different allocator.
312 .sp
313 .LP
314 The \fBnvlist_unpack()\fR function takes a buffer with a packed \fBnvlist_t\fR
315 and unpacks it into a searchable \fBnvlist_t\fR. The library allocates memory
316 for \fBnvlist_t\fR. The caller is responsible for freeing the memory by calling
317 \fBnvlist_free()\fR.
318 .sp
319 .LP
320 The \fBnvlist_xunpack()\fR function differs from \fBnvlist_unpack()\fR in that
321 \fBnvlist_xunpack()\fR can use a different allocator.
322 .sp
323 .LP
324 The \fBnvlist_dup()\fR function makes a copy of \fInvl\fR and updates
325 \fInvlp\fR to point to the copy.
326 .sp
327 .LP
328 The \fBnvlist_xdup()\fR function differs from \fBnvlist_dup()\fR in that
329 \fBnvlist_xdup()\fR can use a different allocator.
330 .sp
331 .LP
332 The \fBnvlist_merge()\fR function adds copies of all name-value pairs from
333 \fBnvlist_t\fR \fInvl\fR to \fBnvlist_t dst\fR. Name-value pairs in dst are
334 replaced with name-value pairs from \fBnvl\fR which have identical names (if
335 dst has the type \fBNV_UNIQUE_NAME\fR), or identical names and types (if dst
336 has the type \fBNV_UNIQUE_NAME_TYPE\fR).
337 .sp
338 .LP
339 The \fBnvlist_lookup_nv_alloc()\fR function retrieves the pointer to the
340 allocator used when manipulating a name-value pair list.
341 .SS "PLUGGABLE ALLOCATORS"
342 .sp
343 .LP
344 Using Pluggable Allocators:
345 .sp
346 .LP
347 The \fBnv_alloc_init()\fR, \fBnv_alloc_reset()\fR and \fBnv_alloc_fini()\fR
348 functions provide an interface that specifies the allocator to be used when
349 manipulating a name-value pair list.
350 .sp
351 .LP
352 The \fBnv_alloc_init()\fR determines allocator properties and puts them into
353 the \fInva\fR argument. You need to specify the \fInv_arg\fR argument, the
354 \fInvo\fR argument and an optional variable argument list. The optional
355 arguments are passed to the (*\fBnv_ao_init()\fR) function.
356 .sp
357 .LP
358 The \fInva\fR argument must be passed to \fBnvlist_xalloc()\fR,
359 \fBnvlist_xpack()\fR, \fBnvlist_xunpack()\fR and \fBnvlist_xdup()\fR.
360 .sp
361 .LP
362 The \fBnv_alloc_reset()\fR function resets the allocator properties to the data
363 specified by \fBnv_alloc_init()\fR. When no (*\fBnv_ao_reset()\fR) function is
364 specified, \fBnv_alloc_reset()\fR is without effect.
365 .sp
366 .LP
367 The \fBnv_alloc_fini()\fR destroys the allocator properties determined by
368 \fBnv_alloc_init()\fR. When a (*\fBnv_ao_fini()\fR) routine is specified, it is
369 called from \fBnv_alloc_fini()\fR.
370 .sp
371 .LP
372 The disposition of the allocated objects and the memory used to store them is
373 left to the allocator implementation.
374 .sp
375 .LP
376 The `nv_alloc_sleep' and `nv_alloc_nosleep' nv_alloc_t pointers may be used
377 with nvlist_xalloc to mimic the behavior of nvlist_alloc with KM_SLEEP and
378 KM_NOSLEEP, respectively.
379 .sp
380 .in +2
381 .nf
382 o nv_alloc_nosleep
383 o nv_alloc_sleep
384 .fi
385 .in -2
386
387 .sp
388 .LP
389 The nvpair framework provides a fixed-buffer allocator, accessible via
390 nv_fixed_ops.
391 .sp
392 .in +2
393 .nf
394 o nv_fixed_ops
395 .fi
396 .in -2
397
398 .sp
399 .LP
400 Given a buffer size and address, the fixed-buffer allocator allows for the
401 creation of nvlists in contexts where malloc or kmem_alloc services may not be
402 available. The fixed-buffer allocator is designed primarily to support the
403 creation of nvlists.
404 .sp
405 .LP
406 Memory freed using \fBnvlist_free()\fR, pair-removal, or similar routines is
407 not reclaimed.
408 .sp
409 .LP
410 When used to initialize the fixed-buffer allocator, nv_alloc_init should be
411 called as follows:
412 .sp
413 .in +2
414 .nf
415 int nv_alloc_init(nv_alloc_t *nva, const nv_alloc_ops_t *nvo,
416 void *bufptr, size_t sz);
417 .fi
418 .in -2
419
420 .sp
421 .LP
422 When invoked on a fixed-buffer, the \fBnv_alloc_reset()\fR function resets the
423 fixed buffer and prepares it for re-use. The framework consumer is responsible
424 for freeing the buffer passed to \fBnv_alloc_init()\fR.
425 .SS "CREATING PLUGGABLE ALLOCATORS"
426 .sp
427 .LP
428 Any producer of name-value pairs may possibily specify his own allocator
429 routines. You must provide the following pluggable allocator operations in the
430 allocator implementation.
431 .sp
432 .in +2
433 .nf
434 int (*nv_ao_init)(nv_alloc_t *nva, va_list nv_valist);
435 void (*nv_ao_fini)(nv_alloc_t *nva);
436 void *(*nv_ao_alloc)(nv_alloc_t *nva, size_t sz);
437 void (*nv_ao_reset)(nv_alloc_t *nva);
438 void (*nv_ao_free)(nv_alloc_t *nva, void *buf, size_t sz);
439 .fi
440 .in -2
441
442 .sp
443 .LP
444 The \fInva\fR argument of the allocator implementation is always the first
445 argument.
446 .sp
447 .LP
448 The optional (*\fBnv_ao_init()\fR ) function is responsible for filling the
449 data specified by \fBnv_alloc_init()\fR into the \fBnva_arg()\fR argument. The
450 (*\fBnv_ao_init()\fR) function is called only when \fBnv_alloc_init()\fR is
451 executed.
452 .sp
453 .LP
454 The optional (*\fBnv_ao_fini()\fR) function is responsible for the cleanup of
455 the allocator implementation. It is called by \fBnv_alloc_fini()\fR.
456 .sp
457 .LP
458 The required (*\fBnv_ao_alloc()\fR) function is used in the nvpair allocation
459 framework for memory allocation. The sz argument specifies the size of the
460 requested buffer.
461 .sp
462 .LP
463 The optional (*\fBnv_ao_reset()\fR) function is responsible for resetting the
464 nva_arg argument to the data specified by \fBnv_alloc_init()\fR.
465 .sp
466 .LP
467 The required (*\fBnv_ao_free()\fR) function is used in the nvpair allocator
468 framework for memory de-allocation. The argument buf is a pointer to a block
469 previously allocated by (*\fBnv_ao_alloc()\fR) function. The size argument sz
470 must exactly match the original allocation.
471 .sp
472 .LP
473 The disposition of the allocated objects and the memory used to store them is
474 left to the allocator implementation.
475 .SH RETURN VALUES
476 .sp
477 .LP
478 For \fBnvlist_alloc()\fR, \fBnvlist_dup()\fR, \fBnvlist_xalloc()\fR, and
479 \fBnvlist_xdup()\fR:
480 .sp
481 .ne 2
482 .na
483 \fB\fB0\fR\fR
484 .ad
485 .RS 10n
486 success
487 .RE
488
489 .sp
490 .ne 2
491 .na
492 \fB\fBEINVAL\fR\fR
493 .ad
494 .RS 10n
495 invalid argument
496 .RE
497
498 .sp
499 .ne 2
500 .na
501 \fB\fBENOMEM\fR\fR
502 .ad
503 .RS 10n
504 insufficient memory
505 .RE
506
507 .sp
508 .LP
509 For \fBnvlist_pack()\fR, \fBnvlist_unpack()\fR, \fBnvlist_xpack()\fR, and
510 \fBnvlist_xunpack()\fR:
511 .sp
512 .ne 2
513 .na
514 \fB\fB0\fR\fR
515 .ad
516 .RS 11n
517 success
518 .RE
519
520 .sp
521 .ne 2
522 .na
523 \fB\fBEINVAL\fR\fR
524 .ad
525 .RS 11n
526 invalid argument
527 .RE
528
529 .sp
530 .ne 2
531 .na
532 \fB\fBENOMEM\fR\fR
533 .ad
534 .RS 11n
535 insufficient memory
536 .RE
537
538 .sp
539 .ne 2
540 .na
541 \fB\fBEFAULT\fR\fR
542 .ad
543 .RS 11n
544 encode/decode error
545 .RE
546
547 .sp
548 .ne 2
549 .na
550 \fB\fBENOTSUP\fR\fR
551 .ad
552 .RS 11n
553 encode/decode method not supported
554 .RE
555
556 .sp
557 .LP
558 For \fBnvlist_size()\fR:
559 .sp
560 .ne 2
561 .na
562 \fB\fB0\fR\fR
563 .ad
564 .RS 10n
565 success
566 .RE
567
568 .sp
569 .ne 2
570 .na
571 \fB\fBEINVAL\fR\fR
572 .ad
573 .RS 10n
574 invalid argument
575 .RE
576
577 .sp
578 .LP
579 For \fBnvlist_lookup_nv_alloc()\fR:
580 .sp
581 .LP
582 pointer to the allocator
583 .SH USAGE
584 .sp
585 .LP
586 The fixed-buffer allocator is very simple allocator. It uses a pre-allocated
587 buffer for memory allocations and it can be used in interrupt context. You are
588 responsible for allocation and de-allocation for the pre-allocated buffer.
589 .SH EXAMPLES
590 .sp
591 .in +2
592 .nf
593 /*
594 * using the fixed-buffer allocator.
595 */
596 #include <sys/nvpair.h>
597
598 /* initialize the nvpair allocator framework */
599 static nv_alloc_t *
600 init(char *buf, size_t size)
601 {
602 nv_alloc_t *nvap;
603
604 if ((nvap = kmem_alloc(sizeof(nv_alloc_t), KM_SLEEP)) == NULL)
605 return (NULL);
606
607 if (nv_alloc_init(nvap, nv_fixed_ops, buf, size) == 0)
608 return (nvap);
609
610 return (NULL);
611 }
612
613 static void
614 fini(nv_alloc_t *nvap)
615 {
616 nv_alloc_fini(nvap);
617 kmem_free(nvap, sizeof(nv_alloc_t));
618 }
619 static int
620 interrupt_context(nv_alloc_t *nva)
621 {
622 nvlist_t *nvl;
623 int error;
624
625 if ((error = nvlist_xalloc(&nvl, NV_UNIQUE_NAME, nva)) != 0)
626 return (-1);
627
628 if ((error = nvlist_add_int32(nvl, "name", 1234)) == 0)
629 error = send_nvl(nvl);
630
631 nvlist_free(nvl);
632 return (error);
633 }
634 .fi
635 .in -2
636
637 .SH CONTEXT
638 .sp
639 .LP
640 The \fBnvlist_alloc()\fR, \fBnvlist_pack()\fR, \fBnvlist_unpack()\fR, and
641 \fBnvlist_dup()\fR functions can be called from interrupt context only if the
642 \fBKM_NOSLEEP\fR flag is set. They can be called from user context with any
643 valid flag.
644 .sp
645 .LP
646 The \fBnvlist_xalloc()\fR, \fBnvlist_xpack()\fR, \fBnvlist_xunpack()\fR, and
647 \fBnvlist_xdup()\fR functions can be called from interrupt context only if (1)
648 the default allocator is used and the \fBKM_NOSLEEP\fR flag is set or (2) the
649 specified allocator did not sleep for free memory (for example, it uses a
650 pre-allocated buffer for memory allocations).
651 .sp
652 .LP
653 These functions can be called from user or kernel context with any valid flag.