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_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
 284cleanup:
 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}
 291