1 /*-
2 * Copyright (C) 2016 Bryan Drewery <bdrewery@FreeBSD.org>
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 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 /*
28 * Helper for mlock(3) to avoid EAGAIN errors
29 */
30
31 #include <sys/types.h>
32 #include <sys/sysctl.h>
33
34 #include <atf-c.h>
35 #include <errno.h>
36 #include <limits.h>
37 #include <stdio.h>
38
39 #define VM_MAX_WIRED "vm.max_user_wired"
40
41 static void
vm_max_wired_sysctl(u_long * old_value,u_long * new_value)42 vm_max_wired_sysctl(u_long *old_value, u_long *new_value)
43 {
44 size_t old_len;
45 size_t new_len = (new_value == NULL ? 0 : sizeof(*new_value));
46
47 if (old_value == NULL)
48 printf("Setting the new value to %lu\n", *new_value);
49 else {
50 ATF_REQUIRE_MSG(sysctlbyname(VM_MAX_WIRED, NULL, &old_len,
51 new_value, new_len) == 0,
52 "sysctlbyname(%s) failed: %s", VM_MAX_WIRED, strerror(errno));
53 }
54
55 ATF_REQUIRE_MSG(sysctlbyname(VM_MAX_WIRED, old_value, &old_len,
56 new_value, new_len) == 0,
57 "sysctlbyname(%s) failed: %s", VM_MAX_WIRED, strerror(errno));
58
59 if (old_value != NULL)
60 printf("Saved the old value (%lu)\n", *old_value);
61 }
62
63 void
set_vm_max_wired(u_long new_value)64 set_vm_max_wired(u_long new_value)
65 {
66 FILE *fp;
67 u_long old_value;
68
69 fp = fopen(VM_MAX_WIRED, "w");
70 if (fp == NULL) {
71 atf_tc_skip("could not open %s for writing: %s",
72 VM_MAX_WIRED, strerror(errno));
73 return;
74 }
75
76 vm_max_wired_sysctl(&old_value, NULL);
77
78 ATF_REQUIRE_MSG(fprintf(fp, "%lu", old_value) > 0,
79 "saving %s failed", VM_MAX_WIRED);
80
81 fclose(fp);
82
83 vm_max_wired_sysctl(NULL, &new_value);
84 }
85
86 void
restore_vm_max_wired(void)87 restore_vm_max_wired(void)
88 {
89 FILE *fp;
90 u_long saved_max_wired;
91
92 fp = fopen(VM_MAX_WIRED, "r");
93 if (fp == NULL) {
94 perror("fopen failed\n");
95 return;
96 }
97
98 if (fscanf(fp, "%lu", &saved_max_wired) != 1) {
99 perror("fscanf failed\n");
100 fclose(fp);
101 return;
102 }
103
104 fclose(fp);
105 printf("old value in %s: %lu\n", VM_MAX_WIRED, saved_max_wired);
106
107 if (saved_max_wired == 0) /* This will cripple the test host */
108 return;
109
110 vm_max_wired_sysctl(NULL, &saved_max_wired);
111 }
112