1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) International Business Machines Corp., 2004
4 * Copyright (c) Linux Test Project, 2004-2017
5 *
6 * DESCRIPTION
7 * hugeshmdt01 - check that largr shared memory is detached correctly
8 *
9 * ALGORITHM
10 * create a large shared memory resource
11 * attach it to the current process and give it a value
12 * call shmdt() using the TEST macro
13 * check the return code
14 * if failure, issue a FAIL message.
15 * otherwise,
16 * if doing functionality testing
17 * attempt to write a value to the large shared memory address
18 * this should generate a SIGSEGV which will be caught in
19 * the signal handler
20 * if correct,
21 * issue a PASS message
22 * otherwise
23 * issue a FAIL message
24 * call cleanup
25 *
26 * HISTORY
27 * 03/2001 - Written by Wayne Boyer
28 * 04/2004 - Updated by Robbie Williamson
29 */
30
31 #include <setjmp.h>
32 #include <limits.h>
33 #include "hugetlb.h"
34
35 static size_t shm_size;
36 static int shm_id_1 = -1;
37 struct shmid_ds buf;
38 static int *shared;
39 static int pass;
40 static sigjmp_buf env;
41
42 static struct tst_option options[] = {
43 {"s:", &nr_opt, "-s num Set the number of the been allocated hugepages"},
44 {NULL, NULL, NULL}
45 };
46
47 static void check_functionality(void);
48 static void sighandler(int sig);
49
hugeshmdt_test(void)50 static void hugeshmdt_test(void)
51 {
52 struct sigaction sa;
53
54 sa.sa_handler = sighandler;
55 sigaction(SIGSEGV, &sa, NULL);
56
57 if (shmdt(shared) == -1)
58 tst_res(TFAIL | TERRNO, "shmdt");
59 else
60 check_functionality();
61
62 /* reattach the shared memory segment in case we are looping */
63 shared = shmat(shm_id_1, 0, 0);
64 if (shared == (void *)-1)
65 tst_brk(TBROK | TERRNO, "shmat #2: reattach");
66
67 /* also reset pass */
68 pass = 0;
69 }
70
check_functionality(void)71 static void check_functionality(void)
72 {
73 /* stat the shared memory segment */
74 if (shmctl(shm_id_1, IPC_STAT, &buf) == -1)
75 tst_brk(TBROK | TERRNO, "shmctl");
76
77 if (buf.shm_nattch != 0) {
78 tst_res(TFAIL, "# of attaches is incorrect");
79 return;
80 }
81
82 /*
83 * Try writing to the shared memory. This should generate a
84 * SIGSEGV which will be caught below.
85 *
86 * This is wrapped by the sigsetjmp() call that will take care of
87 * restoring the program's context in an elegant way in conjunction
88 * with the call to siglongjmp() in the signal handler.
89 *
90 * An attempt to do the assignment without using the sigsetjmp()
91 * and siglongjmp() calls will result in an infinite loop. Program
92 * control is returned to the assignment statement after the execution
93 * of the signal handler and another SIGSEGV will be generated.
94 */
95
96 if (sigsetjmp(env, 1) == 0)
97 *shared = 2;
98
99 if (pass)
100 tst_res(TPASS, "huge shared memory detached correctly");
101 else
102 tst_res(TFAIL, "huge shared memory was not detached "
103 "correctly");
104 }
105
sighandler(int sig)106 static void sighandler(int sig)
107 {
108 /* if we have received a SIGSEGV, we are almost done */
109 if (sig == SIGSEGV) {
110 /* set the global variable and jump back */
111 pass = 1;
112 siglongjmp(env, 1);
113 } else {
114 tst_brk(TBROK, "unexpected signal received: %d", sig);
115 }
116 }
117
setup(void)118 void setup(void)
119 {
120 long hpage_size;
121
122 if (tst_hugepages == 0)
123 tst_brk(TCONF, "No enough hugepages for testing.");
124
125 hpage_size = SAFE_READ_MEMINFO("Hugepagesize:") * 1024;
126
127 shm_size = hpage_size * tst_hugepages / 2;
128 update_shm_size(&shm_size);
129 shmkey = getipckey();
130
131 /* create a shared memory resource with read and write permissions */
132 shm_id_1 = shmget(shmkey, shm_size,
133 SHM_HUGETLB | SHM_RW | IPC_CREAT | IPC_EXCL);
134 if (shm_id_1 == -1)
135 tst_brk(TBROK | TERRNO, "shmget");
136
137 /* attach the shared memory segment */
138 shared = shmat(shm_id_1, 0, 0);
139 if (shared == (void *)-1)
140 tst_brk(TBROK | TERRNO, "shmat #1");
141
142 /* give a value to the shared memory integer */
143 *shared = 4;
144 }
145
cleanup(void)146 void cleanup(void)
147 {
148 rm_shm(shm_id_1);
149 }
150
151 static struct tst_test test = {
152 .needs_root = 1,
153 .options = options,
154 .setup = setup,
155 .cleanup = cleanup,
156 .test_all = hugeshmdt_test,
157 .request_hugepages = 128,
158 };
159