mmap.c (9357B)
1// SPDX-License-Identifier: GPL-2.0 2#include <test_progs.h> 3#include <sys/mman.h> 4#include "test_mmap.skel.h" 5 6struct map_data { 7 __u64 val[512 * 4]; 8}; 9 10static 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 16void 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_obj_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 298cleanup: 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}