1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 2003 Poul-Henning Kamp
5 * All rights reserved.
6 * Copyright (c) 2022 Alexander Motin <mav@FreeBSD.org>
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. The names of the authors may not be used to endorse or promote
17 * products derived from this software without specific prior written
18 * permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #include <sys/types.h>
34 #include <sys/sysctl.h>
35 #include <errno.h>
36 #include <stdlib.h>
37 #include <string.h>
38 #include "libgeom.h"
39
40 /*
41 * Amount of extra space we allocate to try and anticipate the size of
42 * confxml.
43 */
44 #define GEOM_GETXML_SLACK 4096
45
46 /*
47 * Number of times to retry in the face of the size of confxml exceeding
48 * that of our buffer.
49 */
50 #define GEOM_GETXML_RETRIES 4
51
52 /*
53 * Size of confxml buffer to request via getxml control request. It is
54 * expected to be sufficient for single geom and its parents. In case of
55 * overflow fall back to requesting full confxml via sysctl interface.
56 */
57 #define GEOM_GETXML_BUFFER 65536
58
59 char *
geom_getxml(void)60 geom_getxml(void)
61 {
62 char *p;
63 size_t l = 0;
64 int mib[3];
65 size_t sizep;
66 int retries;
67
68 sizep = sizeof(mib) / sizeof(*mib);
69 if (sysctlnametomib("kern.geom.confxml", mib, &sizep) != 0)
70 return (NULL);
71 if (sysctl(mib, sizep, NULL, &l, NULL, 0) != 0)
72 return (NULL);
73 l += GEOM_GETXML_SLACK;
74
75 for (retries = 0; retries < GEOM_GETXML_RETRIES; retries++) {
76 p = malloc(l);
77 if (p == NULL)
78 return (NULL);
79 if (sysctl(mib, sizep, p, &l, NULL, 0) == 0)
80 return (reallocf(p, strlen(p) + 1));
81
82 free(p);
83
84 if (errno != ENOMEM)
85 return (NULL);
86
87 /*
88 * Our buffer wasn't big enough. Make it bigger and
89 * try again.
90 */
91 l *= 2;
92 }
93
94 return (NULL);
95 }
96
97 char *
geom_getxml_geom(const char * class,const char * geom,int parents)98 geom_getxml_geom(const char *class, const char *geom, int parents)
99 {
100 struct gctl_req *r;
101 char *p;
102 const char *errstr;
103 int nargs = 0;
104
105 p = malloc(GEOM_GETXML_BUFFER);
106 if (p == NULL)
107 return (NULL);
108 r = gctl_get_handle();
109 gctl_ro_param(r, "class", -1, class);
110 gctl_ro_param(r, "verb", -1, "getxml");
111 gctl_ro_param(r, "parents", sizeof(parents), &parents);
112 if (geom) {
113 gctl_ro_param(r, "arg0", -1, geom);
114 nargs = 1;
115 }
116 gctl_ro_param(r, "nargs", sizeof(nargs), &nargs);
117 p[0] = '\0';
118 gctl_add_param(r, "output", GEOM_GETXML_BUFFER, p,
119 GCTL_PARAM_WR | GCTL_PARAM_ASCII);
120 errstr = gctl_issue(r);
121 if (errstr != NULL && errstr[0] != '\0') {
122 gctl_free(r);
123 free(p);
124 return (geom_getxml());
125 }
126 gctl_free(r);
127 return (p);
128 }
129