1/*
2 * Stack size mapping is decreased through mlock/munlock call.
3 *
4 * This is to test kernel if it has a problem with shortening [stack]
5 * mapping through several loops of mlock/munlock of /proc/self/maps.
6 *
7 * From:
8 * munlock     76KiB bfef2000-bff05000 rw-p 00000000 00:00 0          [stack]
9 *
10 * To:
11 * munlock     44KiB bfefa000-bff05000 rw-p 00000000 00:00 0          [stack]
12 *
13 * with more iterations - could drop to 0KiB.
14 *
15 * Copyright (C) 2010  Red Hat, Inc.
16 * This program is free software; you can redistribute it and/or
17 * modify it under the terms of version 2 of the GNU General Public
18 * License as published by the Free Software Foundation.
19 *
20 * This program is distributed in the hope that it would be useful,
21 * but WITHOUT ANY WARRANTY; without even the implied warranty of
22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
23 *
24 * Further, this software is distributed without any warranty that it
25 * is free of the rightful claim of any third person regarding
26 * infringement or the like.  Any license provided herein, whether
27 * implied or otherwise, applies only to this software file.  Patent
28 * licenses, if any, provided herein do not apply to combinations of
29 * this program with other software, or any other product whatsoever.
30 *
31 * You should have received a copy of the GNU General Public License
32 * along with this program; if not, write the Free Software
33 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
34 * 02110-1301, USA.
35 */
36#include <sys/mman.h>
37#include <stdio.h>
38#include <string.h>
39#include "test.h"
40
41#define KB 1024
42
43char *TCID = "mlock03";
44int TST_TOTAL = 1;
45
46static void setup(void);
47static void cleanup(void);
48
49int main(int argc, char *argv[])
50{
51	int lc;
52	long from, to;
53	long first = -1, last = -1;
54	char b[KB];
55	FILE *fp;
56
57	tst_parse_opts(argc, argv, NULL, NULL);
58
59	setup();
60
61	for (lc = 0; TEST_LOOPING(lc); lc++) {
62		fp = fopen("/proc/self/maps", "r");
63		if (fp == NULL)
64			tst_brkm(TBROK | TERRNO, cleanup, "fopen");
65		while (!feof(fp)) {
66			if (!fgets(b, KB - 1, fp))
67				break;
68			b[strlen(b) - 1] = '\0';
69			sscanf(b, "%lx-%lx", &from, &to);
70
71			/* Record the initial stack size. */
72			if (lc == 0 && strstr(b, "[stack]") != NULL)
73				first = (to - from) / KB;
74
75			switch (lc & 1) {
76			case 0:
77				if (mlock((const void *)from, to - from) == -1)
78					tst_resm(TINFO | TERRNO,
79						 "mlock failed");
80				break;
81			case 1:
82				if (munlock((void *)from, to - from) == -1)
83					tst_resm(TINFO | TERRNO,
84						 "munlock failed");
85				break;
86			default:
87				break;
88			}
89			tst_resm(TINFO, "%s from %lx to %0lx",
90				 (lc & 1) ? "munlock" : "mlock", from, to);
91
92			/* Record the final stack size. */
93			if (strstr(b, "[stack]") != NULL)
94				last = (to - from) / KB;
95		}
96		fclose(fp);
97	}
98	tst_resm(TINFO, "starting stack size is %ld", first);
99	tst_resm(TINFO, "final stack size is %ld", last);
100	if (last < first)
101		tst_resm(TFAIL, "stack size is decreased.");
102	else
103		tst_resm(TPASS, "stack size is not decreased.");
104
105	cleanup();
106	tst_exit();
107}
108
109void setup(void)
110{
111	tst_require_root();
112
113	tst_sig(FORK, DEF_HANDLER, cleanup);
114	TEST_PAUSE;
115}
116
117void cleanup(void)
118{
119}
120