xref: /titanic_41/usr/src/lib/libipp/libipp.c (revision fcf3ce441efd61da9bb2884968af01cb7c1452cc)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2001-2002 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include <stdio.h>
30 #include <stdlib.h>
31 #include <sys/types.h>
32 #include <sys/stat.h>
33 #include <unistd.h>
34 #include <errno.h>
35 #include <strings.h>
36 #include <string.h>
37 #include <fcntl.h>
38 #include <assert.h>
39 #include <libipp.h>
40 #include <libnvpair.h>
41 #include <ipp/ippctl.h>
42 
43 /*
44  * Debug macros
45  */
46 
47 #if	defined(DEBUG) && !defined(lint)
48 uint32_t	ipp_debug_flags =
49 /*
50  * DBG_IO |
51  */
52 DBG_ERR |
53 0;
54 
55 #define	DBG0(flags, fmt)						\
56 	do {								\
57 		if (flags & ipp_debug_flags)				\
58 			fprintf(stderr, "libipp: " __FN__ ": " fmt);	\
59 	} while (0)
60 
61 #define	DBG1(flags, fmt, a)						\
62 	do {								\
63 		if (flags & ipp_debug_flags)				\
64 			fprintf(stderr, "libipp: " __FN__ ": " fmt, a);	\
65 	} while (0)
66 
67 #define	DBG2(flags, fmt, a, b)						\
68 	do {								\
69 		if (flags & ipp_debug_flags)				\
70 			fprintf(stderr, "libipp: " __FN__ ": " fmt, a,	\
71 			    b);						\
72 	} while (0)
73 
74 #define	DBG3(flags, fmt, a, b, c)					\
75 	do {								\
76 		if (flags & ipp_debug_flags)				\
77 			fprintf(stderr, "libipp: " __FN__ ": " fmt, a,	\
78 			    b, c);					\
79 	} while (0)
80 
81 #else	/* defined(DEBUG) && !defined(lint) */
82 #define	DBG0(flags, fmt)
83 #define	DBG1(flags, fmt, a)
84 #define	DBG2(flags, fmt, a, b)
85 #define	DBG3(flags, fmt, a, b, c)
86 #endif	/* defined(DEBUG) && !defined(lint) */
87 
88 /*
89  * Control device node
90  */
91 
92 #define	IPPCTL_DEVICE	"/devices/pseudo/ippctl@0:ctl"
93 
94 /*
95  * Structures.
96  */
97 
98 typedef	struct array_desc_t {
99 	char	*name;
100 	char	**array;
101 	int	nelt;
102 } array_desc_t;
103 
104 /*
105  * Prototypes
106  */
107 
108 static int	nvlist_callback(nvlist_t *, void *);
109 static int	string_callback(nvlist_t *, void *);
110 static int	string_array_callback(nvlist_t *, void *);
111 static int	dispatch(nvlist_t **, int (*)(nvlist_t *, void *), void *);
112 
113 /*
114  * API functions
115  */
116 #define	__FN__	"ipp_action_create"
117 int
118 ipp_action_create(
119 	const char	*modname,
120 	const char	*aname,
121 	nvlist_t	**nvlpp,
122 	ipp_flags_t	flags)
123 {
124 	nvlist_t	*nvlp;
125 	int		rc;
126 
127 	/*
128 	 * Sanity check the arguments.
129 	 */
130 
131 	if (nvlpp == NULL || modname == NULL || aname == NULL) {
132 		DBG0(DBG_ERR, "bad argument\n");
133 		errno = EINVAL;
134 		return (-1);
135 	}
136 
137 	/*
138 	 * Add our data to the nvlist. (This information will be removed for
139 	 * use by ippctl).
140 	 */
141 
142 	nvlp = *nvlpp;
143 	if ((rc = nvlist_add_byte(nvlp, IPPCTL_OP,
144 	    IPPCTL_OP_ACTION_CREATE)) != 0) {
145 		DBG1(DBG_ERR, "failed to add '%s' to nvlist\n", IPPCTL_OP);
146 		goto failed;
147 	}
148 
149 	if ((rc = nvlist_add_string(nvlp, IPPCTL_MODNAME,
150 	    (char *)modname)) != 0) {
151 		DBG1(DBG_ERR, "failed to add '%s' to nvlist\n",
152 		    IPPCTL_MODNAME);
153 		goto failed;
154 	}
155 
156 	if ((rc = nvlist_add_string(nvlp, IPPCTL_ANAME, (char *)aname)) != 0) {
157 		DBG1(DBG_ERR, "failed to add '%s' to nvlist\n", IPPCTL_ANAME);
158 		goto failed;
159 	}
160 
161 	if ((rc = nvlist_add_uint32(nvlp, IPPCTL_FLAGS, flags)) != 0) {
162 		DBG1(DBG_ERR, "failed to add '%s' to nvlist\n", IPPCTL_FLAGS);
163 		goto failed;
164 	}
165 
166 	/*
167 	 * Talk to the kernel.
168 	 */
169 
170 	return (dispatch(nvlpp, nvlist_callback, (void *)nvlpp));
171 failed:
172 	errno = rc;
173 	return (-1);
174 }
175 #undef	__FN__
176 
177 #define	__FN__	"ipp_action_destroy"
178 int
179 ipp_action_destroy(
180 	const char	*aname,
181 	ipp_flags_t	flags)
182 {
183 	nvlist_t	*nvlp;
184 	int		rc;
185 
186 	/*
187 	 * Sanity check the arguments.
188 	 */
189 
190 	if (aname == NULL) {
191 		DBG0(DBG_ERR, "bad argument\n");
192 		errno = EINVAL;
193 		return (-1);
194 	}
195 
196 	/*
197 	 * Create an nvlist for our data as none is passed into the function.
198 	 */
199 
200 	if ((rc = nvlist_alloc(&nvlp, NV_UNIQUE_NAME, 0)) != 0) {
201 		DBG0(DBG_ERR, "failed to allocate nvlist\n");
202 		nvlp = NULL;
203 		goto failed;
204 	}
205 
206 	if ((rc = nvlist_add_byte(nvlp, IPPCTL_OP,
207 	    IPPCTL_OP_ACTION_DESTROY)) != 0) {
208 		DBG1(DBG_ERR, "failed to add '%s' to nvlist\n", IPPCTL_OP);
209 		goto failed;
210 	}
211 
212 	if ((rc = nvlist_add_string(nvlp, IPPCTL_ANAME, (char *)aname)) != 0) {
213 		DBG1(DBG_ERR, "failed to add '%s' to nvlist\n", IPPCTL_ANAME);
214 		goto failed;
215 	}
216 
217 	if ((rc = nvlist_add_uint32(nvlp, IPPCTL_FLAGS, flags)) != 0) {
218 		DBG1(DBG_ERR, "failed to add '%s' to nvlist\n", IPPCTL_FLAGS);
219 		goto failed;
220 	}
221 
222 	/*
223 	 * Talk to the kernel.
224 	 */
225 
226 	return (dispatch(&nvlp, NULL, NULL));
227 failed:
228 	if (nvlp != NULL)
229 		nvlist_free(nvlp);
230 	errno = rc;
231 	return (-1);
232 }
233 #undef	__FN__
234 
235 #define	__FN__	"ipp_action_modify"
236 int
237 ipp_action_modify(
238 	const char	*aname,
239 	nvlist_t	**nvlpp,
240 	ipp_flags_t	flags)
241 {
242 	nvlist_t	*nvlp;
243 	int		rc;
244 
245 	/*
246 	 * Sanity check the arguments.
247 	 */
248 
249 	if (nvlpp == NULL || aname == NULL) {
250 		DBG0(DBG_ERR, "bad argument\n");
251 		errno = EINVAL;
252 		return (-1);
253 	}
254 
255 	/*
256 	 * Add our data to the nvlist.
257 	 */
258 
259 	nvlp = *nvlpp;
260 	if ((rc = nvlist_add_byte(nvlp, IPPCTL_OP,
261 	    IPPCTL_OP_ACTION_MODIFY)) != 0) {
262 		DBG1(DBG_ERR, "failed to add '%s' to nvlist\n", IPPCTL_OP);
263 		goto failed;
264 	}
265 
266 	if ((rc = nvlist_add_string(nvlp, IPPCTL_ANAME, (char *)aname)) != 0) {
267 		DBG1(DBG_ERR, "failed to add '%s' to nvlist\n", IPPCTL_ANAME);
268 		goto failed;
269 	}
270 
271 	if ((rc = nvlist_add_uint32(nvlp, IPPCTL_FLAGS, flags)) != 0) {
272 		DBG1(DBG_ERR, "failed to add '%s' to nvlist\n", IPPCTL_FLAGS);
273 		goto failed;
274 	}
275 
276 	/*
277 	 * Talk to the kernel.
278 	 */
279 
280 	return (dispatch(nvlpp, nvlist_callback, (void *)nvlpp));
281 failed:
282 	errno = rc;
283 	return (-1);
284 }
285 #undef	__FN__
286 
287 #define	__FN__	"ipp_action_info"
288 int
289 ipp_action_info(
290 	const char	*aname,
291 	int		(*fn)(nvlist_t *, void *),
292 	void		*arg,
293 	ipp_flags_t	flags)
294 {
295 	nvlist_t	*nvlp;
296 	int		rc;
297 
298 	/*
299 	 * Sanity check the arguments.
300 	 */
301 
302 	if (aname == NULL || fn == NULL) {
303 		DBG0(DBG_ERR, "bad argument\n");
304 		errno = EINVAL;
305 		return (-1);
306 	}
307 
308 	/*
309 	 * Create an nvlist for our data.
310 	 */
311 
312 	if ((rc = nvlist_alloc(&nvlp, NV_UNIQUE_NAME, 0)) != 0) {
313 		DBG0(DBG_ERR, "failed to allocate nvlist\n");
314 		nvlp = NULL;
315 	}
316 
317 	if ((rc = nvlist_add_byte(nvlp, IPPCTL_OP,
318 	    IPPCTL_OP_ACTION_INFO)) != 0) {
319 		DBG1(DBG_ERR, "failed to add '%s' to nvlist\n", IPPCTL_OP);
320 		goto failed;
321 	}
322 
323 	if ((rc = nvlist_add_string(nvlp, IPPCTL_ANAME, (char *)aname)) != 0) {
324 		DBG1(DBG_ERR, "failed to add '%s' to nvlist\n", IPPCTL_ANAME);
325 		goto failed;
326 	}
327 
328 	if ((rc = nvlist_add_uint32(nvlp, IPPCTL_FLAGS, flags)) != 0) {
329 		DBG1(DBG_ERR, "failed to add '%s' to nvlist\n", IPPCTL_FLAGS);
330 		goto failed;
331 	}
332 
333 	/*
334 	 * Talk to the kernel.
335 	 */
336 
337 	return (dispatch(&nvlp, fn, arg));
338 failed:
339 	if (nvlp != NULL)
340 		nvlist_free(nvlp);
341 	errno = rc;
342 	return (-1);
343 }
344 #undef	__FN__
345 
346 #define	__FN__	"ipp_action_mod"
347 int
348 ipp_action_mod(
349 	const char	*aname,
350 	char		**modnamep)
351 {
352 	nvlist_t	*nvlp;
353 	int		rc;
354 
355 	/*
356 	 * Sanity check the arguments.
357 	 */
358 
359 	if (aname == NULL || modnamep == NULL) {
360 		DBG0(DBG_ERR, "bad argument\n");
361 		errno = EINVAL;
362 		return (-1);
363 	}
364 
365 	/*
366 	 * Create an nvlist for our data.
367 	 */
368 
369 	if ((rc = nvlist_alloc(&nvlp, NV_UNIQUE_NAME, 0)) != 0) {
370 		DBG0(DBG_ERR, "failed to allocate nvlist\n");
371 		nvlp = NULL;
372 		goto failed;
373 	}
374 
375 	if ((rc = nvlist_add_byte(nvlp, IPPCTL_OP,
376 	    IPPCTL_OP_ACTION_MOD)) != 0) {
377 		DBG1(DBG_ERR, "failed to add '%s' to nvlist\n", IPPCTL_OP);
378 		goto failed;
379 	}
380 
381 	if ((rc = nvlist_add_string(nvlp, IPPCTL_ANAME, (char *)aname)) != 0) {
382 		DBG1(DBG_ERR, "failed to add '%s' to nvlist\n", IPPCTL_ANAME);
383 		goto failed;
384 	}
385 
386 	/*
387 	 * Talk to the kernel.
388 	 */
389 
390 	return (dispatch(&nvlp, string_callback, (void *)modnamep));
391 failed:
392 	if (nvlp != NULL)
393 		nvlist_free(nvlp);
394 	errno = rc;
395 	return (-1);
396 }
397 #undef	__FN__
398 
399 #define	__FN__	"ipp_list_mods"
400 int
401 ipp_list_mods(
402 	char		***modname_arrayp,
403 	int		*neltp)
404 {
405 	nvlist_t	*nvlp;
406 	array_desc_t	ad;
407 	int		rc;
408 
409 	/*
410 	 * Sanity check the arguments.
411 	 */
412 
413 	if (modname_arrayp == NULL || neltp == NULL) {
414 		DBG0(DBG_ERR, "bad argument");
415 		errno = EINVAL;
416 		return (-1);
417 	}
418 
419 	/*
420 	 * Create an nvlist for our data.
421 	 */
422 
423 	if ((rc = nvlist_alloc(&nvlp, NV_UNIQUE_NAME, 0)) != 0) {
424 		DBG0(DBG_ERR, "failed to allocate nvlist\n");
425 		nvlp = NULL;
426 	}
427 
428 	if ((rc = nvlist_add_byte(nvlp, IPPCTL_OP,
429 	    IPPCTL_OP_LIST_MODS)) != 0) {
430 		DBG1(DBG_ERR, "failed to add '%s' to nvlist\n", IPPCTL_OP);
431 		goto failed;
432 	}
433 
434 	/*
435 	 * Talk to the kernel.
436 	 */
437 
438 	ad.name = IPPCTL_MODNAME_ARRAY;
439 	ad.array = NULL;
440 	ad.nelt = 0;
441 
442 	if ((rc = dispatch(&nvlp, string_array_callback, (void *)&ad)) == 0) {
443 		*modname_arrayp = ad.array;
444 		*neltp = ad.nelt;
445 	}
446 
447 	return (rc);
448 failed:
449 	if (nvlp != NULL)
450 		nvlist_free(nvlp);
451 	errno = rc;
452 	return (-1);
453 }
454 #undef	__FN__
455 
456 #define	__FN__	"ipp_mod_list_actions"
457 int
458 ipp_mod_list_actions(
459 	const char	*modname,
460 	char		***aname_arrayp,
461 	int		*neltp)
462 {
463 	nvlist_t	*nvlp;
464 	array_desc_t	ad;
465 	int		rc;
466 
467 	/*
468 	 * Sanity check the arguments.
469 	 */
470 
471 	if (modname == NULL || aname_arrayp == NULL || neltp == NULL) {
472 		DBG0(DBG_ERR, "bad argument");
473 		errno = EINVAL;
474 		return (-1);
475 	}
476 
477 	/*
478 	 * Create an nvlist for our data.
479 	 */
480 
481 	if ((rc = nvlist_alloc(&nvlp, NV_UNIQUE_NAME, 0)) != 0) {
482 		DBG0(DBG_ERR, "failed to allocate nvlist\n");
483 		nvlp = NULL;
484 	}
485 
486 	if ((rc = nvlist_add_byte(nvlp, IPPCTL_OP,
487 	    IPPCTL_OP_MOD_LIST_ACTIONS)) != 0) {
488 		DBG1(DBG_ERR, "failed to add '%s' to nvlist\n", IPPCTL_OP);
489 		goto failed;
490 	}
491 
492 	if ((rc = nvlist_add_string(nvlp, IPPCTL_MODNAME,
493 	    (char *)modname)) != 0) {
494 		DBG1(DBG_ERR, "failed to add '%s' to nvlist\n", IPPCTL_MODNAME);
495 		goto failed;
496 	}
497 
498 	/*
499 	 * Talk to the kernel.
500 	 */
501 
502 	ad.name = IPPCTL_ANAME_ARRAY;
503 	ad.array = NULL;
504 	ad.nelt = 0;
505 
506 	if ((rc = dispatch(&nvlp, string_array_callback, (void *)&ad)) == 0) {
507 		*aname_arrayp = ad.array;
508 		*neltp = ad.nelt;
509 	}
510 
511 	return (rc);
512 failed:
513 	if (nvlp != NULL)
514 		nvlist_free(nvlp);
515 	errno = rc;
516 	return (-1);
517 }
518 #undef	__FN__
519 
520 #define	__FN__	"ipp_free"
521 void
522 ipp_free(
523 	char	*buf)
524 {
525 	free(buf);
526 }
527 #undef	__FN__
528 
529 #define	__FN__	"ipp_free_array"
530 void
531 ipp_free_array(
532 	char	**array,
533 	int	nelt)
534 {
535 	int	i;
536 
537 	assert(array[nelt] == NULL);
538 
539 	for (i = 0; i < nelt; i++)
540 		free(array[i]);
541 
542 	free(array);
543 }
544 #undef	__FN__
545 
546 #define	__FN__	"nvlist_callback"
547 static int
548 nvlist_callback(
549 	nvlist_t	*nvlp,
550 	void		*arg)
551 {
552 	nvlist_t	**nvlpp = (nvlist_t **)arg;
553 	int		rc;
554 
555 	/*
556 	 * Callback function used by ipp_action_create() and
557 	 * ipp_action_modify()
558 	 */
559 
560 	DBG0(DBG_IO, "called\n");
561 
562 	assert(nvlpp != NULL);
563 	assert(*nvlpp == NULL);
564 
565 	/*
566 	 * Duplicate the nvlist and set the given pointer to point at the new
567 	 * copy.
568 	 */
569 
570 	if ((rc = nvlist_dup(nvlp, nvlpp, 0)) != 0) {
571 		DBG0(DBG_ERR, "failed to dup nvlist\n");
572 		errno = rc;
573 		return (-1);
574 	}
575 
576 	return (0);
577 }
578 #undef	__FN__
579 
580 #define	__FN__	"string_callback"
581 static int
582 string_callback(
583 	nvlist_t	*nvlp,
584 	void		*arg)
585 {
586 	char		**namep = (char **)arg;
587 	char		*name;
588 	char		*ptr;
589 	int		rc;
590 
591 	/*
592 	 * Callback function used by ipp_action_mod()
593 	 */
594 
595 	DBG0(DBG_IO, "called\n");
596 
597 	assert(namep != NULL);
598 
599 	/*
600 	 * Look up the module name from the nvlist.
601 	 */
602 
603 	if ((rc = nvlist_lookup_string(nvlp, IPPCTL_MODNAME, &ptr)) != 0) {
604 		DBG0(DBG_ERR, "failed to find string\n");
605 		errno = rc;
606 		return (-1);
607 	}
608 
609 	/*
610 	 * Allocate a duplicate string.
611 	 */
612 
613 	if ((name = strdup(ptr)) == NULL) {
614 		DBG0(DBG_ERR, "failed to duplicate string\n");
615 		return (-1);
616 	}
617 
618 	/*
619 	 * Set the given pointer to point at the string.
620 	 */
621 
622 	*namep = name;
623 	return (0);
624 }
625 #undef	__FN__
626 
627 #define	__FN__	"string_array_callback"
628 static int
629 string_array_callback(
630 	nvlist_t	*nvlp,
631 	void		*arg)
632 {
633 	array_desc_t	*adp = (array_desc_t *)arg;
634 	char		**dst;
635 	char		**src;
636 	uint_t		nelt;
637 	int		i;
638 	int		rc;
639 
640 	/*
641 	 * Callback function used by ipp_list_mods()
642 	 */
643 
644 	DBG0(DBG_IO, "called\n");
645 
646 	assert(adp != NULL);
647 
648 	/*
649 	 * Look up the module name from the nvlist.
650 	 */
651 
652 	if ((rc = nvlist_lookup_string_array(nvlp, adp->name, &src,
653 	    &nelt)) != 0) {
654 		DBG0(DBG_ERR, "failed to find array\n");
655 		errno = rc;
656 		return (-1);
657 	}
658 
659 	/*
660 	 * Allocate an array.
661 	 */
662 
663 	if ((dst = malloc((nelt + 1) * sizeof (char *))) == NULL) {
664 		DBG0(DBG_ERR, "failed to allocate new array\n");
665 		return (-1);
666 	}
667 
668 	/*
669 	 * For each string in the array, allocate a new buffer and copy
670 	 * the string into it.
671 	 */
672 
673 	for (i = 0; i < nelt; i++) {
674 		if ((dst[i] = strdup(src[i])) == NULL) {
675 			while (--i >= 0) {
676 				free(dst[i]);
677 			}
678 			free(dst);
679 			DBG0(DBG_ERR, "failed to duplicate array\n");
680 			return (-1);
681 		}
682 	}
683 	dst[nelt] = NULL;
684 
685 	/*
686 	 * Set the information to be passed back.
687 	 */
688 
689 	adp->array = dst;
690 	adp->nelt = nelt;
691 
692 	return (0);
693 }
694 #undef	__FN__
695 
696 #define	__FN__	"dispatch"
697 static int
698 dispatch(
699 	nvlist_t	**nvlpp,
700 	int		(*fn)(nvlist_t *, void *),
701 	void		*arg)
702 {
703 	char		*cbuf = NULL;
704 	char		*dbuf = NULL;
705 	size_t		cbuflen = 0;
706 	size_t		dbuflen = 0;
707 	size_t		thisbuflen = 0;
708 	size_t		nextbuflen = 0;
709 	int		rc;
710 	ippctl_ioctl_t	iioc;
711 	int		fd;
712 	nvlist_t	*cnvlp;
713 	nvlist_t	*dnvlp = NULL;
714 	int		count;
715 	int		rval;
716 
717 	/*
718 	 * Sanity check the 'command' nvlist.
719 	 */
720 
721 	cnvlp = *nvlpp;
722 	if (cnvlp == NULL) {
723 		rc = EINVAL;
724 		return (-1);
725 	}
726 
727 	/*
728 	 * Pack the nvlist and then free the original.
729 	 */
730 
731 	if ((rc = nvlist_pack(cnvlp, &cbuf, &cbuflen, NV_ENCODE_NATIVE,
732 	    0)) != 0) {
733 		DBG0(DBG_ERR, "failed to pack nvlist\n");
734 		nvlist_free(cnvlp);
735 		errno = rc;
736 		return (-1);
737 	}
738 	nvlist_free(cnvlp);
739 	*nvlpp = NULL;
740 
741 	/*
742 	 * Open the control device node.
743 	 */
744 
745 	DBG1(DBG_IO, "opening %s\n", IPPCTL_DEVICE);
746 	if ((fd = open(IPPCTL_DEVICE, O_RDWR | O_NOCTTY)) == -1) {
747 		DBG1(DBG_ERR, "failed to open %s\n", IPPCTL_DEVICE);
748 		goto command_failed;
749 	}
750 
751 	/*
752 	 * Set up an ioctl structure to point at the packed nvlist.
753 	 */
754 
755 	iioc.ii_buf = cbuf;
756 	iioc.ii_buflen = cbuflen;
757 
758 	/*
759 	 * Issue a command ioctl, passing the ioctl structure.
760 	 */
761 
762 	DBG0(DBG_IO, "command\n");
763 	if ((rc = ioctl(fd, IPPCTL_CMD, &iioc)) < 0) {
764 		DBG0(DBG_ERR, "command ioctl failed\n");
765 		goto command_failed;
766 	}
767 
768 	/*
769 	 * Get back the length of the first data buffer.
770 	 */
771 
772 	if ((nextbuflen = (size_t)rc) == 0) {
773 		DBG0(DBG_ERR, "no data buffer\n");
774 		errno = EPROTO;
775 		goto command_failed;
776 	}
777 
778 	/*
779 	 * Try to re-use the command buffer as the first data buffer.
780 	 */
781 
782 	dbuf = cbuf;
783 	thisbuflen = cbuflen;
784 
785 	count = 0;
786 	while (nextbuflen != 0) {
787 		dbuflen = nextbuflen;
788 
789 		/*
790 		 * Check whether the buffer we have is long enough for the
791 		 * next lot of data. If it isn't, allocate a new one of
792 		 * the appropriate length.
793 		 */
794 
795 		if (nextbuflen > thisbuflen) {
796 			if ((dbuf = realloc(dbuf, nextbuflen)) == NULL) {
797 				DBG0(DBG_ERR,
798 				    "failed to allocate data buffer\n");
799 				goto data_failed;
800 			}
801 			thisbuflen = nextbuflen;
802 		}
803 
804 		/*
805 		 * Set up an ioctl structure to point at the data buffer.
806 		 */
807 
808 		iioc.ii_buf = dbuf;
809 		iioc.ii_buflen = dbuflen;
810 
811 		/*
812 		 * Issue a data ioctl, passing the ioctl structure.
813 		 */
814 
815 		DBG2(DBG_IO, "data[%d]: length = %d\n", count, dbuflen);
816 		if ((rc = ioctl(fd, IPPCTL_DATA, &iioc)) < 0) {
817 			DBG0(DBG_ERR, "data ioctl failed\n");
818 			goto data_failed;
819 		}
820 
821 		/*
822 		 * Get the length of the *next* data buffer, if there is
823 		 * one.
824 		 */
825 
826 		nextbuflen = (size_t)rc;
827 		DBG1(DBG_IO, "nextbuflen = %d\n", nextbuflen);
828 
829 		/*
830 		 * Unpack the nvlist that the current data buffer should
831 		 * now contain.
832 		 */
833 
834 		if ((rc = nvlist_unpack(dbuf, dbuflen, &dnvlp, 0)) != 0) {
835 			DBG0(DBG_ERR, "failed to unpack nvlist\n");
836 			errno = rc;
837 			goto data_failed;
838 		}
839 
840 		/*
841 		 * The first data buffer should contain the kernel function's
842 		 * return code. Subsequent buffers contain nvlists which
843 		 * should be passed to the given callback function.
844 		 */
845 
846 		if (count == 0) {
847 			if ((rc = nvlist_lookup_int32(dnvlp, IPPCTL_RC,
848 			    &rval)) != 0) {
849 				DBG0(DBG_ERR, "failed to find return code\n");
850 				nvlist_free(dnvlp);
851 				errno = rc;
852 				goto data_failed;
853 			}
854 		} else {
855 			if (fn != NULL)
856 				if (fn(dnvlp, arg) != 0) {
857 
858 					/*
859 					 * The callback function returned
860 					 * a non-zero value. Abort any further
861 					 * data collection.
862 					 */
863 
864 					nvlist_free(dnvlp);
865 					free(dbuf);
866 				}
867 		}
868 
869 		/*
870 		 * Free the nvlist now that we have extracted the return
871 		 * code or called the callback function.
872 		 */
873 
874 		nvlist_free(dnvlp);
875 		dnvlp = NULL;
876 
877 		count++;
878 	}
879 
880 	/*
881 	 * Free the data buffer as data collection is now complete.
882 	 */
883 
884 	free(dbuf);
885 
886 	/*
887 	 * Close the control device.
888 	 */
889 
890 	(void) close(fd);
891 
892 	/*
893 	 * If the kernel returned an error, we should return an error.
894 	 * and set errno.
895 	 */
896 
897 	if (rval != 0) {
898 		DBG1(DBG_IO, "kernel return code = %d\n", rval);
899 		errno = rval;
900 		return (-1);
901 	}
902 
903 	return (0);
904 
905 command_failed:
906 	free(cbuf);
907 	if (fd != -1)
908 		(void) close(fd);
909 	return (-1);
910 
911 data_failed:
912 	if (dbuf != NULL)
913 		free(dbuf);
914 	(void) close(fd);
915 	return (-1);
916 }
917 #undef	__FN__
918