1 /*
2 * Copyright (c) International Business Machines Corp., 2004
3 * Copyright (c) Linux Test Project, 2004-2017
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
13 * the GNU General Public License for more details.
14 */
15
16 /*
17 * DESCRIPTION
18 * hugeshmdt01 - check that largr shared memory is detached correctly
19 *
20 * ALGORITHM
21 * create a large shared memory resource
22 * attach it to the current process and give it a value
23 * call shmdt() using the TEST macro
24 * check the return code
25 * if failure, issue a FAIL message.
26 * otherwise,
27 * if doing functionality testing
28 * attempt to write a value to the large shared memory address
29 * this should generate a SIGSEGV which will be caught in
30 * the signal handler
31 * if correct,
32 * issue a PASS message
33 * otherwise
34 * issue a FAIL message
35 * call cleanup
36 *
37 * HISTORY
38 * 03/2001 - Written by Wayne Boyer
39 * 04/2004 - Updated by Robbie Williamson
40 */
41
42 #include <setjmp.h>
43 #include <limits.h>
44 #include "hugetlb.h"
45 #include "hugetlb.h"
46
47 static size_t shm_size;
48 static int shm_id_1 = -1;
49 struct shmid_ds buf;
50 static int *shared;
51 static int pass;
52 static sigjmp_buf env;
53
54 static long hugepages = 128;
55 static struct tst_option options[] = {
56 {"s:", &nr_opt, "-s num Set the number of the been allocated hugepages"},
57 {NULL, NULL, NULL}
58 };
59
60 static void check_functionality(void);
61 static void sighandler(int sig);
62
hugeshmdt_test(void)63 static void hugeshmdt_test(void)
64 {
65 struct sigaction sa;
66
67 sa.sa_handler = sighandler;
68 sigaction(SIGSEGV, &sa, NULL);
69
70 if (shmdt(shared) == -1)
71 tst_res(TFAIL | TERRNO, "shmdt");
72 else
73 check_functionality();
74
75 /* reattach the shared memory segment in case we are looping */
76 shared = shmat(shm_id_1, 0, 0);
77 if (shared == (void *)-1)
78 tst_brk(TBROK | TERRNO, "shmat #2: reattach");
79
80 /* also reset pass */
81 pass = 0;
82 }
83
check_functionality(void)84 static void check_functionality(void)
85 {
86 /* stat the shared memory segment */
87 if (shmctl(shm_id_1, IPC_STAT, &buf) == -1)
88 tst_brk(TBROK | TERRNO, "shmctl");
89
90 if (buf.shm_nattch != 0) {
91 tst_res(TFAIL, "# of attaches is incorrect");
92 return;
93 }
94
95 /*
96 * Try writing to the shared memory. This should generate a
97 * SIGSEGV which will be caught below.
98 *
99 * This is wrapped by the sigsetjmp() call that will take care of
100 * restoring the program's context in an elegant way in conjunction
101 * with the call to siglongjmp() in the signal handler.
102 *
103 * An attempt to do the assignment without using the sigsetjmp()
104 * and siglongjmp() calls will result in an infinite loop. Program
105 * control is returned to the assignment statement after the execution
106 * of the signal handler and another SIGSEGV will be generated.
107 */
108
109 if (sigsetjmp(env, 1) == 0)
110 *shared = 2;
111
112 if (pass)
113 tst_res(TPASS, "huge shared memory detached correctly");
114 else
115 tst_res(TFAIL, "huge shared memory was not detached "
116 "correctly");
117 }
118
sighandler(int sig)119 static void sighandler(int sig)
120 {
121 /* if we have received a SIGSEGV, we are almost done */
122 if (sig == SIGSEGV) {
123 /* set the global variable and jump back */
124 pass = 1;
125 siglongjmp(env, 1);
126 } else {
127 tst_brk(TBROK, "unexpected signal received: %d", sig);
128 }
129 }
130
setup(void)131 void setup(void)
132 {
133 long hpage_size;
134
135 save_nr_hugepages();
136 if (nr_opt)
137 hugepages = SAFE_STRTOL(nr_opt, 0, LONG_MAX);
138
139 set_sys_tune("nr_hugepages", hugepages, 1);
140 hpage_size = SAFE_READ_MEMINFO("Hugepagesize:") * 1024;
141
142 shm_size = hpage_size * hugepages / 2;
143 update_shm_size(&shm_size);
144 shmkey = getipckey();
145
146 /* create a shared memory resource with read and write permissions */
147 shm_id_1 = shmget(shmkey, shm_size,
148 SHM_HUGETLB | SHM_RW | IPC_CREAT | IPC_EXCL);
149 if (shm_id_1 == -1)
150 tst_brk(TBROK | TERRNO, "shmget");
151
152 /* attach the shared memory segment */
153 shared = shmat(shm_id_1, 0, 0);
154 if (shared == (void *)-1)
155 tst_brk(TBROK | TERRNO, "shmat #1");
156
157 /* give a value to the shared memory integer */
158 *shared = 4;
159 }
160
cleanup(void)161 void cleanup(void)
162 {
163 rm_shm(shm_id_1);
164 restore_nr_hugepages();
165 }
166
167 static struct tst_test test = {
168 .needs_root = 1,
169 .options = options,
170 .setup = setup,
171 .cleanup = cleanup,
172 .test_all = hugeshmdt_test,
173 };
174