1 /*-
2 * Copyright (c) 2003 Poul-Henning Kamp
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. The names of the authors may not be used to endorse or promote
14 * products derived from this software without specific prior written
15 * permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $FreeBSD$
30 */
31
32 #include <sys/types.h>
33 #include <sys/sysctl.h>
34 #include <errno.h>
35 #include <stdlib.h>
36 #include <string.h>
37 #include "libgeom.h"
38
39 /*
40 * Amount of extra space we allocate to try and anticipate the size of
41 * confxml.
42 */
43 #define GEOM_GETXML_SLACK 4096
44
45 /*
46 * Number of times to retry in the face of the size of confxml exceeding
47 * that of our buffer.
48 */
49 #define GEOM_GETXML_RETRIES 4
50
51 char *
geom_getxml(void)52 geom_getxml(void)
53 {
54 char *p;
55 size_t l = 0;
56 int mib[3];
57 size_t sizep;
58 int retries;
59
60 sizep = sizeof(mib) / sizeof(*mib);
61 if (sysctlnametomib("kern.geom.confxml", mib, &sizep) != 0)
62 return (NULL);
63 if (sysctl(mib, sizep, NULL, &l, NULL, 0) != 0)
64 return (NULL);
65 l += GEOM_GETXML_SLACK;
66
67 for (retries = 0; retries < GEOM_GETXML_RETRIES; retries++) {
68 p = malloc(l);
69 if (p == NULL)
70 return (NULL);
71 if (sysctl(mib, sizep, p, &l, NULL, 0) == 0)
72 return (reallocf(p, strlen(p) + 1));
73
74 free(p);
75
76 if (errno != ENOMEM)
77 return (NULL);
78
79 /*
80 * Our buffer wasn't big enough. Make it bigger and
81 * try again.
82 */
83 l *= 2;
84 }
85
86 return (NULL);
87 }
88