LXR linux/tools/testing/selftests/bpf/prog

   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}
 305