aboutsummaryrefslogtreecommitdiff
path: root/lib/libgeom/geom_getxml.c
blob: a6bb130fd5a7a360610a30e7a9f871d83ee8410a (plain) (blame)
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
/*-
 * SPDX-License-Identifier: BSD-3-Clause-FreeBSD
 *
 * Copyright (c) 2003 Poul-Henning Kamp
 * All rights reserved.
 * Copyright (c) 2022 Alexander Motin <mav@FreeBSD.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The names of the authors may not be used to endorse or promote
 *    products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD$
 */

#include <sys/types.h>
#include <sys/sysctl.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include "libgeom.h"

/*
 * Amount of extra space we allocate to try and anticipate the size of
 * confxml.
 */
#define	GEOM_GETXML_SLACK	4096

/*
 * Number of times to retry in the face of the size of confxml exceeding
 * that of our buffer.
 */
#define	GEOM_GETXML_RETRIES	4

/*
 * Size of confxml buffer to request via getxml control request.  It is
 * expected to be sufficient for single geom and its parents.  In case of
 * overflow fall back to requesting full confxml via sysctl interface.
 */
#define	GEOM_GETXML_BUFFER	65536

char *
geom_getxml(void)
{
	char *p;
	size_t l = 0;
	int mib[3];
	size_t sizep;
	int retries;

	sizep = sizeof(mib) / sizeof(*mib);
	if (sysctlnametomib("kern.geom.confxml", mib, &sizep) != 0)
		return (NULL);
	if (sysctl(mib, sizep, NULL, &l, NULL, 0) != 0)
		return (NULL);
	l += GEOM_GETXML_SLACK;

	for (retries = 0; retries < GEOM_GETXML_RETRIES; retries++) {
		p = malloc(l);
		if (p == NULL)
			return (NULL);
		if (sysctl(mib, sizep, p, &l, NULL, 0) == 0)
			return (reallocf(p, strlen(p) + 1));

		free(p);

		if (errno != ENOMEM)
			return (NULL);

		/*
		 * Our buffer wasn't big enough. Make it bigger and
		 * try again.
		 */
		l *= 2;
	}

	return (NULL);
}

char *
geom_getxml_geom(const char *class, const char *geom, int parents)
{
	struct gctl_req *r;
	char *p;
	const char *errstr;
	int nargs = 0;

	p = malloc(GEOM_GETXML_BUFFER);
	if (p == NULL)
		return (NULL);
	r = gctl_get_handle();
	gctl_ro_param(r, "class", -1, class);
	gctl_ro_param(r, "verb", -1, "getxml");
	gctl_ro_param(r, "parents", sizeof(parents), &parents);
	if (geom) {
		gctl_ro_param(r, "arg0", -1, geom);
		nargs = 1;
	}
	gctl_ro_param(r, "nargs", sizeof(nargs), &nargs);
	p[0] = '\0';
	gctl_add_param(r, "output", GEOM_GETXML_BUFFER, p,
	    GCTL_PARAM_WR | GCTL_PARAM_ASCII);
	errstr = gctl_issue(r);
	if (errstr != NULL && errstr[0] != '\0') {
		gctl_free(r);
		free(p);
		return (geom_getxml());
	}
	gctl_free(r);
	return (p);
}