tools/testing/selftests/bpf/get_cgroup_id_user.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (c) 2018 Facebook
   3
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <string.h>
   7 #include <errno.h>
   8 #include <fcntl.h>
   9 #include <syscall.h>
  10 #include <unistd.h>
  11 #include <linux/perf_event.h>
  12 #include <sys/ioctl.h>
  13 #include <sys/time.h>
  14 #include <sys/types.h>
  15 #include <sys/stat.h>
  16
  17 #include <linux/bpf.h>
  18 #include <bpf/bpf.h>
  19 #include <bpf/libbpf.h>
  20
  21 #include "cgroup_helpers.h"
  22 #include "testing_helpers.h"
  23
  24 #define CHECK(condition, tag, format...) ({             \
  25         int __ret = !!(condition);                      \
  26         if (__ret) {                                    \
  27                 printf("%s:FAIL:%s ", __func__, tag);   \
  28                 printf(format);                         \
  29         } else {                                        \
  30                 printf("%s:PASS:%s\n", __func__, tag);  \
  31         }                                               \
  32         __ret;                                          \
  33 })
  34
  35 static int bpf_find_map(const char *test, struct bpf_object *obj,
  36                         const char *name)
  37 {
  38         struct bpf_map *map;
  39
  40         map = bpf_object__find_map_by_name(obj, name);
  41         if (!map)
  42                 return -1;
  43         return bpf_map__fd(map);
  44 }
  45
  46 #define TEST_CGROUP "/test-bpf-get-cgroup-id/"
  47
  48 int main(int argc, char **argv)
  49 {
  50         const char *probe_name = "syscalls/sys_enter_nanosleep";
  51         const char *file = "get_cgroup_id_kern.o";
  52         int err, bytes, efd, prog_fd, pmu_fd;
  53         int cgroup_fd, cgidmap_fd, pidmap_fd;
  54         struct perf_event_attr attr = {};
  55         struct bpf_object *obj;
  56         __u64 kcgid = 0, ucgid;
  57         __u32 key = 0, pid;
  58         int exit_code = 1;
  59         char buf[256];
  60         const struct timespec req = {
  61                 .tv_sec = 1,
  62                 .tv_nsec = 0,
  63         };
  64
  65         cgroup_fd = cgroup_setup_and_join(TEST_CGROUP);
  66         if (CHECK(cgroup_fd < 0, "cgroup_setup_and_join", "err %d errno %d\n", cgroup_fd, errno))
  67                 return 1;
  68
  69         /* Use libbpf 1.0 API mode */
  70         libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
  71
  72         err = bpf_prog_test_load(file, BPF_PROG_TYPE_TRACEPOINT, &obj, &prog_fd);
  73         if (CHECK(err, "bpf_prog_test_load", "err %d errno %d\n", err, errno))
  74                 goto cleanup_cgroup_env;
  75
  76         cgidmap_fd = bpf_find_map(__func__, obj, "cg_ids");
  77         if (CHECK(cgidmap_fd < 0, "bpf_find_map", "err %d errno %d\n",
  78                   cgidmap_fd, errno))
  79                 goto close_prog;
  80
  81         pidmap_fd = bpf_find_map(__func__, obj, "pidmap");
  82         if (CHECK(pidmap_fd < 0, "bpf_find_map", "err %d errno %d\n",
  83                   pidmap_fd, errno))
  84                 goto close_prog;
  85
  86         pid = getpid();
  87         bpf_map_update_elem(pidmap_fd, &key, &pid, 0);
  88
  89         snprintf(buf, sizeof(buf),
  90                  "/sys/kernel/debug/tracing/events/%s/id", probe_name);
  91         efd = open(buf, O_RDONLY, 0);
  92         if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno))
  93                 goto close_prog;
  94         bytes = read(efd, buf, sizeof(buf));
  95         close(efd);
  96         if (CHECK(bytes <= 0 || bytes >= sizeof(buf), "read",
  97                   "bytes %d errno %d\n", bytes, errno))
  98                 goto close_prog;
  99
 100         attr.config = strtol(buf, NULL, 0);
 101         attr.type = PERF_TYPE_TRACEPOINT;
 102         attr.sample_type = PERF_SAMPLE_RAW;
 103         attr.sample_period = 1;
 104         attr.wakeup_events = 1;
 105
 106         /* attach to this pid so the all bpf invocations will be in the
 107          * cgroup associated with this pid.
 108          */
 109         pmu_fd = syscall(__NR_perf_event_open, &attr, getpid(), -1, -1, 0);
 110         if (CHECK(pmu_fd < 0, "perf_event_open", "err %d errno %d\n", pmu_fd,
 111                   errno))
 112                 goto close_prog;
 113
 114         err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
 115         if (CHECK(err, "perf_event_ioc_enable", "err %d errno %d\n", err,
 116                   errno))
 117                 goto close_pmu;
 118
 119         err = ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd);
 120         if (CHECK(err, "perf_event_ioc_set_bpf", "err %d errno %d\n", err,
 121                   errno))
 122                 goto close_pmu;
 123
 124         /* trigger some syscalls */
 125         syscall(__NR_nanosleep, &req, NULL);
 126
 127         err = bpf_map_lookup_elem(cgidmap_fd, &key, &kcgid);
 128         if (CHECK(err, "bpf_map_lookup_elem", "err %d errno %d\n", err, errno))
 129                 goto close_pmu;
 130
 131         ucgid = get_cgroup_id(TEST_CGROUP);
 132         if (CHECK(kcgid != ucgid, "compare_cgroup_id",
 133                   "kern cgid %llx user cgid %llx", kcgid, ucgid))
 134                 goto close_pmu;
 135
 136         exit_code = 0;
 137         printf("%s:PASS\n", argv[0]);
 138
 139 close_pmu:
 140         close(pmu_fd);
 141 close_prog:
 142         bpf_object__close(obj);
 143 cleanup_cgroup_env:
 144         cleanup_cgroup_environment();
 145         return exit_code;
 146 }