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 
43 char *TCID = "mlock03";
44 int TST_TOTAL = 1;
45 
46 static void setup(void);
47 static void cleanup(void);
48 
49 int 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 
109 void setup(void)
110 {
111 	tst_require_root();
112 
113 	tst_sig(FORK, DEF_HANDLER, cleanup);
114 	TEST_PAUSE;
115 }
116 
117 void cleanup(void)
118 {
119 }
120