1 // SPDX-License-Identifier: GPL-2.0
2 #include <test_progs.h>
3 #include <sys/mman.h>
4 #include "test_mmap.skel.h"
5 
6 struct map_data {
7 	__u64 val[512 * 4];
8 };
9 
10 static size_t roundup_page(size_t sz)
11 {
12 	long page_size = sysconf(_SC_PAGE_SIZE);
13 	return (sz + page_size - 1) / page_size * page_size;
14 }
15 
16 void test_mmap(void)
17 {
18 	const size_t bss_sz = roundup_page(sizeof(struct test_mmap__bss));
19 	const size_t map_sz = roundup_page(sizeof(struct map_data));
20 	const int zero = 0, one = 1, two = 2, far = 1500;
21 	const long page_size = sysconf(_SC_PAGE_SIZE);
22 	int err, duration = 0, i, data_map_fd, data_map_id, tmp_fd, rdmap_fd;
23 	struct bpf_map *data_map, *bss_map;
24 	void *bss_mmaped = NULL, *map_mmaped = NULL, *tmp0, *tmp1, *tmp2;
25 	struct test_mmap__bss *bss_data;
26 	struct bpf_map_info map_info;
27 	__u32 map_info_sz = sizeof(map_info);
28 	struct map_data *map_data;
29 	struct test_mmap *skel;
30 	__u64 val = 0;
31 
32 	skel = test_mmap__open();
33 	if (CHECK(!skel, "skel_open", "skeleton open failed\n"))
34 		return;
35 
36 	err = bpf_map__set_max_entries(skel->maps.rdonly_map, page_size);
37 	if (CHECK(err != 0, "bpf_map__set_max_entries", "bpf_map__set_max_entries failed\n"))
38 		goto cleanup;
39 
40 	/* at least 4 pages of data */
41 	err = bpf_map__set_max_entries(skel->maps.data_map,
42 				       4 * (page_size / sizeof(u64)));
43 	if (CHECK(err != 0, "bpf_map__set_max_entries", "bpf_map__set_max_entries failed\n"))
44 		goto cleanup;
45 
46 	err = test_mmap__load(skel);
47 	if (CHECK(err != 0, "skel_load", "skeleton load failed\n"))
48 		goto cleanup;
49 
50 	bss_map = skel->maps.bss;
51 	data_map = skel->maps.data_map;
52 	data_map_fd = bpf_map__fd(data_map);
53 
54 	rdmap_fd = bpf_map__fd(skel->maps.rdonly_map);
55 	tmp1 = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, rdmap_fd, 0);
56 	if (CHECK(tmp1 != MAP_FAILED, "rdonly_write_mmap", "unexpected success\n")) {
57 		munmap(tmp1, page_size);
58 		goto cleanup;
59 	}
60 	/* now double-check if it's mmap()'able at all */
61 	tmp1 = mmap(NULL, page_size, PROT_READ, MAP_SHARED, rdmap_fd, 0);
62 	if (CHECK(tmp1 == MAP_FAILED, "rdonly_read_mmap", "failed: %d\n", errno))
63 		goto cleanup;
64 
65 	/* get map's ID */
66 	memset(&map_info, 0, map_info_sz);
67 	err = bpf_map_get_info_by_fd(data_map_fd, &map_info, &map_info_sz);
68 	if (CHECK(err, "map_get_info", "failed %d\n", errno))
69 		goto cleanup;
70 	data_map_id = map_info.id;
71 
72 	/* mmap BSS map */
73 	bss_mmaped = mmap(NULL, bss_sz, PROT_READ | PROT_WRITE, MAP_SHARED,
74 			  bpf_map__fd(bss_map), 0);
75 	if (CHECK(bss_mmaped == MAP_FAILED, "bss_mmap",
76 		  ".bss mmap failed: %d\n", errno)) {
77 		bss_mmaped = NULL;
78 		goto cleanup;
79 	}
80 	/* map as R/W first */
81 	map_mmaped = mmap(NULL, map_sz, PROT_READ | PROT_WRITE, MAP_SHARED,
82 			  data_map_fd, 0);
83 	if (CHECK(map_mmaped == MAP_FAILED, "data_mmap",
84 		  "data_map mmap failed: %d\n", errno)) {
85 		map_mmaped = NULL;
86 		goto cleanup;
87 	}
88 
89 	bss_data = bss_mmaped;
90 	map_data = map_mmaped;
91 
92 	CHECK_FAIL(bss_data->in_val);
93 	CHECK_FAIL(bss_data->out_val);
94 	CHECK_FAIL(skel->bss->in_val);
95 	CHECK_FAIL(skel->bss->out_val);
96 	CHECK_FAIL(map_data->val[0]);
97 	CHECK_FAIL(map_data->val[1]);
98 	CHECK_FAIL(map_data->val[2]);
99 	CHECK_FAIL(map_data->val[far]);
100 
101 	err = test_mmap__attach(skel);
102 	if (CHECK(err, "attach_raw_tp", "err %d\n", err))
103 		goto cleanup;
104 
105 	bss_data->in_val = 123;
106 	val = 111;
107 	CHECK_FAIL(bpf_map_update_elem(data_map_fd, &zero, &val, 0));
108 
109 	usleep(1);
110 
111 	CHECK_FAIL(bss_data->in_val != 123);
112 	CHECK_FAIL(bss_data->out_val != 123);
113 	CHECK_FAIL(skel->bss->in_val != 123);
114 	CHECK_FAIL(skel->bss->out_val != 123);
115 	CHECK_FAIL(map_data->val[0] != 111);
116 	CHECK_FAIL(map_data->val[1] != 222);
117 	CHECK_FAIL(map_data->val[2] != 123);
118 	CHECK_FAIL(map_data->val[far] != 3 * 123);
119 
120 	CHECK_FAIL(bpf_map_lookup_elem(data_map_fd, &zero, &val));
121 	CHECK_FAIL(val != 111);
122 	CHECK_FAIL(bpf_map_lookup_elem(data_map_fd, &one, &val));
123 	CHECK_FAIL(val != 222);
124 	CHECK_FAIL(bpf_map_lookup_elem(data_map_fd, &two, &val));
125 	CHECK_FAIL(val != 123);
126 	CHECK_FAIL(bpf_map_lookup_elem(data_map_fd, &far, &val));
127 	CHECK_FAIL(val != 3 * 123);
128 
129 	/* data_map freeze should fail due to R/W mmap() */
130 	err = bpf_map_freeze(data_map_fd);
131 	if (CHECK(!err || errno != EBUSY, "no_freeze",
132 		  "data_map freeze succeeded: err=%d, errno=%d\n", err, errno))
133 		goto cleanup;
134 
135 	err = mprotect(map_mmaped, map_sz, PROT_READ);
136 	if (CHECK(err, "mprotect_ro", "mprotect to r/o failed %d\n", errno))
137 		goto cleanup;
138 
139 	/* unmap R/W mapping */
140 	err = munmap(map_mmaped, map_sz);
141 	map_mmaped = NULL;
142 	if (CHECK(err, "data_map_munmap", "data_map munmap failed: %d\n", errno))
143 		goto cleanup;
144 
145 	/* re-map as R/O now */
146 	map_mmaped = mmap(NULL, map_sz, PROT_READ, MAP_SHARED, data_map_fd, 0);
147 	if (CHECK(map_mmaped == MAP_FAILED, "data_mmap",
148 		  "data_map R/O mmap failed: %d\n", errno)) {
149 		map_mmaped = NULL;
150 		goto cleanup;
151 	}
152 	err = mprotect(map_mmaped, map_sz, PROT_WRITE);
153 	if (CHECK(!err, "mprotect_wr", "mprotect() succeeded unexpectedly!\n"))
154 		goto cleanup;
155 	err = mprotect(map_mmaped, map_sz, PROT_EXEC);
156 	if (CHECK(!err, "mprotect_ex", "mprotect() succeeded unexpectedly!\n"))
157 		goto cleanup;
158 	map_data = map_mmaped;
159 
160 	/* map/unmap in a loop to test ref counting */
161 	for (i = 0; i < 10; i++) {
162 		int flags = i % 2 ? PROT_READ : PROT_WRITE;
163 		void *p;
164 
165 		p = mmap(NULL, map_sz, flags, MAP_SHARED, data_map_fd, 0);
166 		if (CHECK_FAIL(p == MAP_FAILED))
167 			goto cleanup;
168 		err = munmap(p, map_sz);
169 		if (CHECK_FAIL(err))
170 			goto cleanup;
171 	}
172 
173 	/* data_map freeze should now succeed due to no R/W mapping */
174 	err = bpf_map_freeze(data_map_fd);
175 	if (CHECK(err, "freeze", "data_map freeze failed: err=%d, errno=%d\n",
176 		  err, errno))
177 		goto cleanup;
178 
179 	/* mapping as R/W now should fail */
180 	tmp1 = mmap(NULL, map_sz, PROT_READ | PROT_WRITE, MAP_SHARED,
181 		    data_map_fd, 0);
182 	if (CHECK(tmp1 != MAP_FAILED, "data_mmap", "mmap succeeded\n")) {
183 		munmap(tmp1, map_sz);
184 		goto cleanup;
185 	}
186 
187 	bss_data->in_val = 321;
188 	usleep(1);
189 	CHECK_FAIL(bss_data->in_val != 321);
190 	CHECK_FAIL(bss_data->out_val != 321);
191 	CHECK_FAIL(skel->bss->in_val != 321);
192 	CHECK_FAIL(skel->bss->out_val != 321);
193 	CHECK_FAIL(map_data->val[0] != 111);
194 	CHECK_FAIL(map_data->val[1] != 222);
195 	CHECK_FAIL(map_data->val[2] != 321);
196 	CHECK_FAIL(map_data->val[far] != 3 * 321);
197 
198 	/* check some more advanced mmap() manipulations */
199 
200 	tmp0 = mmap(NULL, 4 * page_size, PROT_READ, MAP_SHARED | MAP_ANONYMOUS,
201 			  -1, 0);
202 	if (CHECK(tmp0 == MAP_FAILED, "adv_mmap0", "errno %d\n", errno))
203 		goto cleanup;
204 
205 	/* map all but last page: pages 1-3 mapped */
206 	tmp1 = mmap(tmp0, 3 * page_size, PROT_READ, MAP_SHARED | MAP_FIXED,
207 			  data_map_fd, 0);
208 	if (CHECK(tmp0 != tmp1, "adv_mmap1", "tmp0: %p, tmp1: %p\n", tmp0, tmp1)) {
209 		munmap(tmp0, 4 * page_size);
210 		goto cleanup;
211 	}
212 
213 	/* unmap second page: pages 1, 3 mapped */
214 	err = munmap(tmp1 + page_size, page_size);
215 	if (CHECK(err, "adv_mmap2", "errno %d\n", errno)) {
216 		munmap(tmp1, 4 * page_size);
217 		goto cleanup;
218 	}
219 
220 	/* map page 2 back */
221 	tmp2 = mmap(tmp1 + page_size, page_size, PROT_READ,
222 		    MAP_SHARED | MAP_FIXED, data_map_fd, 0);
223 	if (CHECK(tmp2 == MAP_FAILED, "adv_mmap3", "errno %d\n", errno)) {
224 		munmap(tmp1, page_size);
225 		munmap(tmp1 + 2*page_size, 2 * page_size);
226 		goto cleanup;
227 	}
228 	CHECK(tmp1 + page_size != tmp2, "adv_mmap4",
229 	      "tmp1: %p, tmp2: %p\n", tmp1, tmp2);
230 
231 	/* re-map all 4 pages */
232 	tmp2 = mmap(tmp1, 4 * page_size, PROT_READ, MAP_SHARED | MAP_FIXED,
233 		    data_map_fd, 0);
234 	if (CHECK(tmp2 == MAP_FAILED, "adv_mmap5", "errno %d\n", errno)) {
235 		munmap(tmp1, 4 * page_size); /* unmap page 1 */
236 		goto cleanup;
237 	}
238 	CHECK(tmp1 != tmp2, "adv_mmap6", "tmp1: %p, tmp2: %p\n", tmp1, tmp2);
239 
240 	map_data = tmp2;
241 	CHECK_FAIL(bss_data->in_val != 321);
242 	CHECK_FAIL(bss_data->out_val != 321);
243 	CHECK_FAIL(skel->bss->in_val != 321);
244 	CHECK_FAIL(skel->bss->out_val != 321);
245 	CHECK_FAIL(map_data->val[0] != 111);
246 	CHECK_FAIL(map_data->val[1] != 222);
247 	CHECK_FAIL(map_data->val[2] != 321);
248 	CHECK_FAIL(map_data->val[far] != 3 * 321);
249 
250 	munmap(tmp2, 4 * page_size);
251 
252 	/* map all 4 pages, but with pg_off=1 page, should fail */
253 	tmp1 = mmap(NULL, 4 * page_size, PROT_READ, MAP_SHARED | MAP_FIXED,
254 		    data_map_fd, page_size /* initial page shift */);
255 	if (CHECK(tmp1 != MAP_FAILED, "adv_mmap7", "unexpected success")) {
256 		munmap(tmp1, 4 * page_size);
257 		goto cleanup;
258 	}
259 
260 	tmp1 = mmap(NULL, map_sz, PROT_READ, MAP_SHARED, data_map_fd, 0);
261 	if (CHECK(tmp1 == MAP_FAILED, "last_mmap", "failed %d\n", errno))
262 		goto cleanup;
263 
264 	test_mmap__destroy(skel);
265 	skel = NULL;
266 	CHECK_FAIL(munmap(bss_mmaped, bss_sz));
267 	bss_mmaped = NULL;
268 	CHECK_FAIL(munmap(map_mmaped, map_sz));
269 	map_mmaped = NULL;
270 
271 	/* map should be still held by active mmap */
272 	tmp_fd = bpf_map_get_fd_by_id(data_map_id);
273 	if (CHECK(tmp_fd < 0, "get_map_by_id", "failed %d\n", errno)) {
274 		munmap(tmp1, map_sz);
275 		goto cleanup;
276 	}
277 	close(tmp_fd);
278 
279 	/* this should release data map finally */
280 	munmap(tmp1, map_sz);
281 
282 	/* we need to wait for RCU grace period */
283 	for (i = 0; i < 10000; i++) {
284 		__u32 id = data_map_id - 1;
285 		if (bpf_map_get_next_id(id, &id) || id > data_map_id)
286 			break;
287 		usleep(1);
288 	}
289 
290 	/* should fail to get map FD by non-existing ID */
291 	tmp_fd = bpf_map_get_fd_by_id(data_map_id);
292 	if (CHECK(tmp_fd >= 0, "get_map_by_id_after",
293 		  "unexpectedly succeeded %d\n", tmp_fd)) {
294 		close(tmp_fd);
295 		goto cleanup;
296 	}
297 
298 cleanup:
299 	if (bss_mmaped)
300 		CHECK_FAIL(munmap(bss_mmaped, bss_sz));
301 	if (map_mmaped)
302 		CHECK_FAIL(munmap(map_mmaped, map_sz));
303 	test_mmap__destroy(skel);
304 }
305