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