1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * It tests the mlock/mlock2() when they are invoked
4 * on randomly memory region.
5 */
6 #include <unistd.h>
7 #include <sys/resource.h>
8 #include <sys/capability.h>
9 #include <sys/mman.h>
10 #include <linux/mman.h>
11 #include <fcntl.h>
12 #include <string.h>
13 #include <sys/ipc.h>
14 #include <sys/shm.h>
15 #include <time.h>
16 #include "mlock2.h"
17
18 #define CHUNK_UNIT (128 * 1024)
19 #define MLOCK_RLIMIT_SIZE (CHUNK_UNIT * 2)
20 #define MLOCK_WITHIN_LIMIT_SIZE CHUNK_UNIT
21 #define MLOCK_OUTOF_LIMIT_SIZE (CHUNK_UNIT * 3)
22
23 #define TEST_LOOP 100
24 #define PAGE_ALIGN(size, ps) (((size) + ((ps) - 1)) & ~((ps) - 1))
25
set_cap_limits(rlim_t max)26 int set_cap_limits(rlim_t max)
27 {
28 struct rlimit new;
29 cap_t cap = cap_init();
30
31 new.rlim_cur = max;
32 new.rlim_max = max;
33 if (setrlimit(RLIMIT_MEMLOCK, &new)) {
34 perror("setrlimit() returns error\n");
35 return -1;
36 }
37
38 /* drop capabilities including CAP_IPC_LOCK */
39 if (cap_set_proc(cap)) {
40 perror("cap_set_proc() returns error\n");
41 return -2;
42 }
43
44 return 0;
45 }
46
get_proc_locked_vm_size(void)47 int get_proc_locked_vm_size(void)
48 {
49 FILE *f;
50 int ret = -1;
51 char line[1024] = {0};
52 unsigned long lock_size = 0;
53
54 f = fopen("/proc/self/status", "r");
55 if (!f) {
56 perror("fopen");
57 return -1;
58 }
59
60 while (fgets(line, 1024, f)) {
61 if (strstr(line, "VmLck")) {
62 ret = sscanf(line, "VmLck:\t%8lu kB", &lock_size);
63 if (ret <= 0) {
64 printf("sscanf() on VmLck error: %s: %d\n",
65 line, ret);
66 fclose(f);
67 return -1;
68 }
69 fclose(f);
70 return (int)(lock_size << 10);
71 }
72 }
73
74 perror("cannot parse VmLck in /proc/self/status\n");
75 fclose(f);
76 return -1;
77 }
78
79 /*
80 * Get the MMUPageSize of the memory region including input
81 * address from proc file.
82 *
83 * return value: on error case, 0 will be returned.
84 * Otherwise the page size(in bytes) is returned.
85 */
get_proc_page_size(unsigned long addr)86 int get_proc_page_size(unsigned long addr)
87 {
88 FILE *smaps;
89 char *line;
90 unsigned long mmupage_size = 0;
91 size_t size;
92
93 smaps = seek_to_smaps_entry(addr);
94 if (!smaps) {
95 printf("Unable to parse /proc/self/smaps\n");
96 return 0;
97 }
98
99 while (getline(&line, &size, smaps) > 0) {
100 if (!strstr(line, "MMUPageSize")) {
101 free(line);
102 line = NULL;
103 size = 0;
104 continue;
105 }
106
107 /* found the MMUPageSize of this section */
108 if (sscanf(line, "MMUPageSize: %8lu kB",
109 &mmupage_size) < 1) {
110 printf("Unable to parse smaps entry for Size:%s\n",
111 line);
112 break;
113 }
114
115 }
116 free(line);
117 if (smaps)
118 fclose(smaps);
119 return mmupage_size << 10;
120 }
121
122 /*
123 * Test mlock/mlock2() on provided memory chunk.
124 * It expects the mlock/mlock2() to be successful (within rlimit)
125 *
126 * With allocated memory chunk [p, p + alloc_size), this
127 * test will choose start/len randomly to perform mlock/mlock2
128 * [start, start + len] memory range. The range is within range
129 * of the allocated chunk.
130 *
131 * The memory region size alloc_size is within the rlimit.
132 * So we always expect a success of mlock/mlock2.
133 *
134 * VmLck is assumed to be 0 before this test.
135 *
136 * return value: 0 - success
137 * else: failure
138 */
test_mlock_within_limit(char * p,int alloc_size)139 int test_mlock_within_limit(char *p, int alloc_size)
140 {
141 int i;
142 int ret = 0;
143 int locked_vm_size = 0;
144 struct rlimit cur;
145 int page_size = 0;
146
147 getrlimit(RLIMIT_MEMLOCK, &cur);
148 if (cur.rlim_cur < alloc_size) {
149 printf("alloc_size[%d] < %u rlimit,lead to mlock failure\n",
150 alloc_size, (unsigned int)cur.rlim_cur);
151 return -1;
152 }
153
154 srand(time(NULL));
155 for (i = 0; i < TEST_LOOP; i++) {
156 /*
157 * - choose mlock/mlock2 randomly
158 * - choose lock_size randomly but lock_size < alloc_size
159 * - choose start_offset randomly but p+start_offset+lock_size
160 * < p+alloc_size
161 */
162 int is_mlock = !!(rand() % 2);
163 int lock_size = rand() % alloc_size;
164 int start_offset = rand() % (alloc_size - lock_size);
165
166 if (is_mlock)
167 ret = mlock(p + start_offset, lock_size);
168 else
169 ret = mlock2_(p + start_offset, lock_size,
170 MLOCK_ONFAULT);
171
172 if (ret) {
173 printf("%s() failure at |%p(%d)| mlock:|%p(%d)|\n",
174 is_mlock ? "mlock" : "mlock2",
175 p, alloc_size,
176 p + start_offset, lock_size);
177 return ret;
178 }
179 }
180
181 /*
182 * Check VmLck left by the tests.
183 */
184 locked_vm_size = get_proc_locked_vm_size();
185 page_size = get_proc_page_size((unsigned long)p);
186 if (page_size == 0) {
187 printf("cannot get proc MMUPageSize\n");
188 return -1;
189 }
190
191 if (locked_vm_size > PAGE_ALIGN(alloc_size, page_size) + page_size) {
192 printf("test_mlock_within_limit() left VmLck:%d on %d chunk\n",
193 locked_vm_size, alloc_size);
194 return -1;
195 }
196
197 return 0;
198 }
199
200
201 /*
202 * We expect the mlock/mlock2() to be fail (outof limitation)
203 *
204 * With allocated memory chunk [p, p + alloc_size), this
205 * test will randomly choose start/len and perform mlock/mlock2
206 * on [start, start+len] range.
207 *
208 * The memory region size alloc_size is above the rlimit.
209 * And the len to be locked is higher than rlimit.
210 * So we always expect a failure of mlock/mlock2.
211 * No locked page number should be increased as a side effect.
212 *
213 * return value: 0 - success
214 * else: failure
215 */
test_mlock_outof_limit(char * p,int alloc_size)216 int test_mlock_outof_limit(char *p, int alloc_size)
217 {
218 int i;
219 int ret = 0;
220 int locked_vm_size = 0, old_locked_vm_size = 0;
221 struct rlimit cur;
222
223 getrlimit(RLIMIT_MEMLOCK, &cur);
224 if (cur.rlim_cur >= alloc_size) {
225 printf("alloc_size[%d] >%u rlimit, violates test condition\n",
226 alloc_size, (unsigned int)cur.rlim_cur);
227 return -1;
228 }
229
230 old_locked_vm_size = get_proc_locked_vm_size();
231 srand(time(NULL));
232 for (i = 0; i < TEST_LOOP; i++) {
233 int is_mlock = !!(rand() % 2);
234 int lock_size = (rand() % (alloc_size - cur.rlim_cur))
235 + cur.rlim_cur;
236 int start_offset = rand() % (alloc_size - lock_size);
237
238 if (is_mlock)
239 ret = mlock(p + start_offset, lock_size);
240 else
241 ret = mlock2_(p + start_offset, lock_size,
242 MLOCK_ONFAULT);
243 if (ret == 0) {
244 printf("%s() succeeds? on %p(%d) mlock%p(%d)\n",
245 is_mlock ? "mlock" : "mlock2",
246 p, alloc_size,
247 p + start_offset, lock_size);
248 return -1;
249 }
250 }
251
252 locked_vm_size = get_proc_locked_vm_size();
253 if (locked_vm_size != old_locked_vm_size) {
254 printf("tests leads to new mlocked page: old[%d], new[%d]\n",
255 old_locked_vm_size,
256 locked_vm_size);
257 return -1;
258 }
259
260 return 0;
261 }
262
main(int argc,char ** argv)263 int main(int argc, char **argv)
264 {
265 char *p = NULL;
266 int ret = 0;
267
268 if (set_cap_limits(MLOCK_RLIMIT_SIZE))
269 return -1;
270
271 p = malloc(MLOCK_WITHIN_LIMIT_SIZE);
272 if (p == NULL) {
273 perror("malloc() failure\n");
274 return -1;
275 }
276 ret = test_mlock_within_limit(p, MLOCK_WITHIN_LIMIT_SIZE);
277 if (ret)
278 return ret;
279 munlock(p, MLOCK_WITHIN_LIMIT_SIZE);
280 free(p);
281
282
283 p = malloc(MLOCK_OUTOF_LIMIT_SIZE);
284 if (p == NULL) {
285 perror("malloc() failure\n");
286 return -1;
287 }
288 ret = test_mlock_outof_limit(p, MLOCK_OUTOF_LIMIT_SIZE);
289 if (ret)
290 return ret;
291 munlock(p, MLOCK_OUTOF_LIMIT_SIZE);
292 free(p);
293
294 return 0;
295 }
296