tools/testing/selftests/bpf/prog_tests/mmap.c

   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_and_load();
  33         if (CHECK(!skel, "skel_open_and_load", "skeleton open/load failed\n"))
  34                 return;
  35
  36         bss_map = skel->maps.bss;
  37         data_map = skel->maps.data_map;
  38         data_map_fd = bpf_map__fd(data_map);
  39
  40         rdmap_fd = bpf_map__fd(skel->maps.rdonly_map);
  41         tmp1 = mmap(NULL, 4096, PROT_READ | PROT_WRITE, MAP_SHARED, rdmap_fd, 0);
  42         if (CHECK(tmp1 != MAP_FAILED, "rdonly_write_mmap", "unexpected success\n")) {
  43                 munmap(tmp1, 4096);
  44                 goto cleanup;
  45         }
  46         /* now double-check if it's mmap()'able at all */
  47         tmp1 = mmap(NULL, 4096, PROT_READ, MAP_SHARED, rdmap_fd, 0);
  48         if (CHECK(tmp1 == MAP_FAILED, "rdonly_read_mmap", "failed: %d\n", errno))
  49                 goto cleanup;
  50
  51         /* get map's ID */
  52         memset(&map_info, 0, map_info_sz);
  53         err = bpf_obj_get_info_by_fd(data_map_fd, &map_info, &map_info_sz);
  54         if (CHECK(err, "map_get_info", "failed %d\n", errno))
  55                 goto cleanup;
  56         data_map_id = map_info.id;
  57
  58         /* mmap BSS map */
  59         bss_mmaped = mmap(NULL, bss_sz, PROT_READ | PROT_WRITE, MAP_SHARED,
  60                           bpf_map__fd(bss_map), 0);
  61         if (CHECK(bss_mmaped == MAP_FAILED, "bss_mmap",
  62                   ".bss mmap failed: %d\n", errno)) {
  63                 bss_mmaped = NULL;
  64                 goto cleanup;
  65         }
  66         /* map as R/W first */
  67         map_mmaped = mmap(NULL, map_sz, PROT_READ | PROT_WRITE, MAP_SHARED,
  68                           data_map_fd, 0);
  69         if (CHECK(map_mmaped == MAP_FAILED, "data_mmap",
  70                   "data_map mmap failed: %d\n", errno)) {
  71                 map_mmaped = NULL;
  72                 goto cleanup;
  73         }
  74
  75         bss_data = bss_mmaped;
  76         map_data = map_mmaped;
  77
  78         CHECK_FAIL(bss_data->in_val);
  79         CHECK_FAIL(bss_data->out_val);
  80         CHECK_FAIL(skel->bss->in_val);
  81         CHECK_FAIL(skel->bss->out_val);
  82         CHECK_FAIL(map_data->val[0]);
  83         CHECK_FAIL(map_data->val[1]);
  84         CHECK_FAIL(map_data->val[2]);
  85         CHECK_FAIL(map_data->val[far]);
  86
  87         err = test_mmap__attach(skel);
  88         if (CHECK(err, "attach_raw_tp", "err %d\n", err))
  89                 goto cleanup;
  90
  91         bss_data->in_val = 123;
  92         val = 111;
  93         CHECK_FAIL(bpf_map_update_elem(data_map_fd, &zero, &val, 0));
  94
  95         usleep(1);
  96
  97         CHECK_FAIL(bss_data->in_val != 123);
  98         CHECK_FAIL(bss_data->out_val != 123);
  99         CHECK_FAIL(skel->bss->in_val != 123);
 100         CHECK_FAIL(skel->bss->out_val != 123);
 101         CHECK_FAIL(map_data->val[0] != 111);
 102         CHECK_FAIL(map_data->val[1] != 222);
 103         CHECK_FAIL(map_data->val[2] != 123);
 104         CHECK_FAIL(map_data->val[far] != 3 * 123);
 105
 106         CHECK_FAIL(bpf_map_lookup_elem(data_map_fd, &zero, &val));
 107         CHECK_FAIL(val != 111);
 108         CHECK_FAIL(bpf_map_lookup_elem(data_map_fd, &one, &val));
 109         CHECK_FAIL(val != 222);
 110         CHECK_FAIL(bpf_map_lookup_elem(data_map_fd, &two, &val));
 111         CHECK_FAIL(val != 123);
 112         CHECK_FAIL(bpf_map_lookup_elem(data_map_fd, &far, &val));
 113         CHECK_FAIL(val != 3 * 123);
 114
 115         /* data_map freeze should fail due to R/W mmap() */
 116         err = bpf_map_freeze(data_map_fd);
 117         if (CHECK(!err || errno != EBUSY, "no_freeze",
 118                   "data_map freeze succeeded: err=%d, errno=%d\n", err, errno))
 119                 goto cleanup;
 120
 121         err = mprotect(map_mmaped, map_sz, PROT_READ);
 122         if (CHECK(err, "mprotect_ro", "mprotect to r/o failed %d\n", errno))
 123                 goto cleanup;
 124
 125         /* unmap R/W mapping */
 126         err = munmap(map_mmaped, map_sz);
 127         map_mmaped = NULL;
 128         if (CHECK(err, "data_map_munmap", "data_map munmap failed: %d\n", errno))
 129                 goto cleanup;
 130
 131         /* re-map as R/O now */
 132         map_mmaped = mmap(NULL, map_sz, PROT_READ, MAP_SHARED, data_map_fd, 0);
 133         if (CHECK(map_mmaped == MAP_FAILED, "data_mmap",
 134                   "data_map R/O mmap failed: %d\n", errno)) {
 135                 map_mmaped = NULL;
 136                 goto cleanup;
 137         }
 138         err = mprotect(map_mmaped, map_sz, PROT_WRITE);
 139         if (CHECK(!err, "mprotect_wr", "mprotect() succeeded unexpectedly!\n"))
 140                 goto cleanup;
 141         err = mprotect(map_mmaped, map_sz, PROT_EXEC);
 142         if (CHECK(!err, "mprotect_ex", "mprotect() succeeded unexpectedly!\n"))
 143                 goto cleanup;
 144         map_data = map_mmaped;
 145
 146         /* map/unmap in a loop to test ref counting */
 147         for (i = 0; i < 10; i++) {
 148                 int flags = i % 2 ? PROT_READ : PROT_WRITE;
 149                 void *p;
 150
 151                 p = mmap(NULL, map_sz, flags, MAP_SHARED, data_map_fd, 0);
 152                 if (CHECK_FAIL(p == MAP_FAILED))
 153                         goto cleanup;
 154                 err = munmap(p, map_sz);
 155                 if (CHECK_FAIL(err))
 156                         goto cleanup;
 157         }
 158
 159         /* data_map freeze should now succeed due to no R/W mapping */
 160         err = bpf_map_freeze(data_map_fd);
 161         if (CHECK(err, "freeze", "data_map freeze failed: err=%d, errno=%d\n",
 162                   err, errno))
 163                 goto cleanup;
 164
 165         /* mapping as R/W now should fail */
 166         tmp1 = mmap(NULL, map_sz, PROT_READ | PROT_WRITE, MAP_SHARED,
 167                     data_map_fd, 0);
 168         if (CHECK(tmp1 != MAP_FAILED, "data_mmap", "mmap succeeded\n")) {
 169                 munmap(tmp1, map_sz);
 170                 goto cleanup;
 171         }
 172
 173         bss_data->in_val = 321;
 174         usleep(1);
 175         CHECK_FAIL(bss_data->in_val != 321);
 176         CHECK_FAIL(bss_data->out_val != 321);
 177         CHECK_FAIL(skel->bss->in_val != 321);
 178         CHECK_FAIL(skel->bss->out_val != 321);
 179         CHECK_FAIL(map_data->val[0] != 111);
 180         CHECK_FAIL(map_data->val[1] != 222);
 181         CHECK_FAIL(map_data->val[2] != 321);
 182         CHECK_FAIL(map_data->val[far] != 3 * 321);
 183
 184         /* check some more advanced mmap() manipulations */
 185
 186         tmp0 = mmap(NULL, 4 * page_size, PROT_READ, MAP_SHARED | MAP_ANONYMOUS,
 187                           -1, 0);
 188         if (CHECK(tmp0 == MAP_FAILED, "adv_mmap0", "errno %d\n", errno))
 189                 goto cleanup;
 190
 191         /* map all but last page: pages 1-3 mapped */
 192         tmp1 = mmap(tmp0, 3 * page_size, PROT_READ, MAP_SHARED | MAP_FIXED,
 193                           data_map_fd, 0);
 194         if (CHECK(tmp0 != tmp1, "adv_mmap1", "tmp0: %p, tmp1: %p\n", tmp0, tmp1)) {
 195                 munmap(tmp0, 4 * page_size);
 196                 goto cleanup;
 197         }
 198
 199         /* unmap second page: pages 1, 3 mapped */
 200         err = munmap(tmp1 + page_size, page_size);
 201         if (CHECK(err, "adv_mmap2", "errno %d\n", errno)) {
 202                 munmap(tmp1, 4 * page_size);
 203                 goto cleanup;
 204         }
 205
 206         /* map page 2 back */
 207         tmp2 = mmap(tmp1 + page_size, page_size, PROT_READ,
 208                     MAP_SHARED | MAP_FIXED, data_map_fd, 0);
 209         if (CHECK(tmp2 == MAP_FAILED, "adv_mmap3", "errno %d\n", errno)) {
 210                 munmap(tmp1, page_size);
 211                 munmap(tmp1 + 2*page_size, 2 * page_size);
 212                 goto cleanup;
 213         }
 214         CHECK(tmp1 + page_size != tmp2, "adv_mmap4",
 215               "tmp1: %p, tmp2: %p\n", tmp1, tmp2);
 216
 217         /* re-map all 4 pages */
 218         tmp2 = mmap(tmp1, 4 * page_size, PROT_READ, MAP_SHARED | MAP_FIXED,
 219                     data_map_fd, 0);
 220         if (CHECK(tmp2 == MAP_FAILED, "adv_mmap5", "errno %d\n", errno)) {
 221                 munmap(tmp1, 4 * page_size); /* unmap page 1 */
 222                 goto cleanup;
 223         }
 224         CHECK(tmp1 != tmp2, "adv_mmap6", "tmp1: %p, tmp2: %p\n", tmp1, tmp2);
 225
 226         map_data = tmp2;
 227         CHECK_FAIL(bss_data->in_val != 321);
 228         CHECK_FAIL(bss_data->out_val != 321);
 229         CHECK_FAIL(skel->bss->in_val != 321);
 230         CHECK_FAIL(skel->bss->out_val != 321);
 231         CHECK_FAIL(map_data->val[0] != 111);
 232         CHECK_FAIL(map_data->val[1] != 222);
 233         CHECK_FAIL(map_data->val[2] != 321);
 234         CHECK_FAIL(map_data->val[far] != 3 * 321);
 235
 236         munmap(tmp2, 4 * page_size);
 237
 238         /* map all 4 pages, but with pg_off=1 page, should fail */
 239         tmp1 = mmap(NULL, 4 * page_size, PROT_READ, MAP_SHARED | MAP_FIXED,
 240                     data_map_fd, page_size /* initial page shift */);
 241         if (CHECK(tmp1 != MAP_FAILED, "adv_mmap7", "unexpected success")) {
 242                 munmap(tmp1, 4 * page_size);
 243                 goto cleanup;
 244         }
 245
 246         tmp1 = mmap(NULL, map_sz, PROT_READ, MAP_SHARED, data_map_fd, 0);
 247         if (CHECK(tmp1 == MAP_FAILED, "last_mmap", "failed %d\n", errno))
 248                 goto cleanup;
 249
 250         test_mmap__destroy(skel);
 251         skel = NULL;
 252         CHECK_FAIL(munmap(bss_mmaped, bss_sz));
 253         bss_mmaped = NULL;
 254         CHECK_FAIL(munmap(map_mmaped, map_sz));
 255         map_mmaped = NULL;
 256
 257         /* map should be still held by active mmap */
 258         tmp_fd = bpf_map_get_fd_by_id(data_map_id);
 259         if (CHECK(tmp_fd < 0, "get_map_by_id", "failed %d\n", errno)) {
 260                 munmap(tmp1, map_sz);
 261                 goto cleanup;
 262         }
 263         close(tmp_fd);
 264
 265         /* this should release data map finally */
 266         munmap(tmp1, map_sz);
 267
 268         /* we need to wait for RCU grace period */
 269         for (i = 0; i < 10000; i++) {
 270                 __u32 id = data_map_id - 1;
 271                 if (bpf_map_get_next_id(id, &id) || id > data_map_id)
 272                         break;
 273                 usleep(1);
 274         }
 275
 276         /* should fail to get map FD by non-existing ID */
 277         tmp_fd = bpf_map_get_fd_by_id(data_map_id);
 278         if (CHECK(tmp_fd >= 0, "get_map_by_id_after",
 279                   "unexpectedly succeeded %d\n", tmp_fd)) {
 280                 close(tmp_fd);
 281                 goto cleanup;
 282         }
 283
 284 cleanup:
 285         if (bss_mmaped)
 286                 CHECK_FAIL(munmap(bss_mmaped, bss_sz));
 287         if (map_mmaped)
 288                 CHECK_FAIL(munmap(map_mmaped, map_sz));
 289         test_mmap__destroy(skel);
 290 }